id
stringlengths 11
17
| article_id
stringlengths 8
11
| path
stringlengths 11
60
| section_title
stringlengths 1
1.33k
| educational_score
float64 0
5.16
| domain
stringclasses 4
values | document_type
stringclasses 5
values | domain_scores
sequencelengths 0
3
| document_type_scores
sequencelengths 0
4
| text
stringlengths 1
110k
| authors
sequencelengths 0
8.02k
| article_url
stringlengths 3
63
| license_type
stringclasses 1
value | license_url
stringclasses 15
values | language
stringclasses 45
values | language_score
float64 0
1
|
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
39057070_p37 | 39057070 | sec[3]/p[7] | 4. Discussion | 4.316406 | biomedical | Study | [
0.9990234375,
0.00040435791015625,
0.00035953521728515625
] | [
0.7802734375,
0.00160980224609375,
0.217529296875,
0.0004639625549316406
] | On the other hand, Vit E deficiency is related to a greater synthesis of the platelet-activating factor (PAF), which is produced by perivascular mast cells. The increase in the PAF leads to inflammation and high immunothrombosis in COVID-19 patients . This has been associated with the antiphospholipid antibody syndrome (aPLs), which is an autoimmune thrombophilia mediated by autoantibodies directed against plasma phospholipid-binding proteins, mainly β2 glycoprotein I and prothrombin . The exact mechanism by which these aPLs induce thrombosis is still not well understood in SARS-CoV-2 infection. In this sense, the results in different studies are controversial; for example, some papers report an increase while others a decrease . However, there is evidence of an increase in aPLs antibodies in SARS-CoV-2 infection . In this regard, a study that measured the concentration of aCL IgG antibodies in the positive serum of COVID-19 before and after vaccination with different vaccines or following SARS-CoV-2 infection was not clinically pathogenic for the risk of thrombosis . However, another study demonstrated that vaccination did not trigger early autoantibody production . Despite the above, treatment with Vit E has shown that it may inhibit the synthesis of the PAF, which induces platelet aggregation . Although the relationship between aPLs and SARS-CoV-2 infection is not solid, a healthy diet containing PAF inhibitors, such as Vit E and flavonoids, could have an effect not only on inflammation but also the reduction in OS, thus preventing the harmful effects of thrombosis . | [
"María Elena Soto",
"Linaloe Manzano-Pech",
"Verónica Guarner-Lans",
"Adrían Palacios-Chavarría",
"Rafael Ricardo Valdez-Vázquez",
"Raúl Martínez-Memije",
"Mohammed El-Hafidi",
"Félix Leao Rodríguez-Fierros",
"Israel Pérez-Torres"
] | https://doi.org/10.3390/cimb46070429 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057070_p38 | 39057070 | sec[4]/p[0] | 5. Conclusions | 4.042969 | biomedical | Study | [
0.99951171875,
0.00019872188568115234,
0.00014591217041015625
] | [
0.99853515625,
0.0005512237548828125,
0.0007772445678710938,
0.00007742643356323242
] | In conclusion, these results suggest that treatment with Vit E as monotherapy can contribute to restoring the FA profile of the PLs, which is modified by the SARS-CoV-2 infection, and this leads to a decrease in LPO, OS, and the inflammatory process. Therefore, treatment with Vit E could be used as an adjuvant therapy for a SARS-CoV-2 infection. | [
"María Elena Soto",
"Linaloe Manzano-Pech",
"Verónica Guarner-Lans",
"Adrían Palacios-Chavarría",
"Rafael Ricardo Valdez-Vázquez",
"Raúl Martínez-Memije",
"Mohammed El-Hafidi",
"Félix Leao Rodríguez-Fierros",
"Israel Pérez-Torres"
] | https://doi.org/10.3390/cimb46070429 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057070_p39 | 39057070 | sec[4]/sec[0]/p[0] | 5.1. Perspectives | 3.935547 | biomedical | Study | [
0.99951171875,
0.00014257431030273438,
0.00020456314086914062
] | [
0.9072265625,
0.06903076171875,
0.02313232421875,
0.0005350112915039062
] | Although there are currently different vaccines against SARS-CoV-2 that allow us to reduce the severity of the infection, the administration of Vit E as an adjuvant therapy can decrease the oxidation of PLs in the cell membrane and contribute to increasing the innate immune response. Treatment with Vit E could also restore and decrease the intricate disturbance in the metabolism of lipids, which is an important step in the process of infection and replication of SARS-CoV-2. | [
"María Elena Soto",
"Linaloe Manzano-Pech",
"Verónica Guarner-Lans",
"Adrían Palacios-Chavarría",
"Rafael Ricardo Valdez-Vázquez",
"Raúl Martínez-Memije",
"Mohammed El-Hafidi",
"Félix Leao Rodríguez-Fierros",
"Israel Pérez-Torres"
] | https://doi.org/10.3390/cimb46070429 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
39057070_p40 | 39057070 | sec[4]/sec[1]/p[0] | 5.2. Study Limitations | 4.078125 | biomedical | Study | [
0.99951171875,
0.0002002716064453125,
0.00021350383758544922
] | [
0.99951171875,
0.0002658367156982422,
0.00021648406982421875,
0.00005525350570678711
] | A limitation of this study is the small group of patients with COVID-19 that were included. Another limitation of this study is that the analysis of the FA of the FAAIPFs for gas chromatography cannot evaluate changes in each of the phospholipid fractions, including phosphatidylcholine, sphingomyelin, phosphatidylserine, phosphatidylethanolamine, sphingomyelin, phosphatidylserine, phosphatidylethanolamine, and phosphatidylinositol in the serum of the COVID-19 patients; it only gives us an approximation of the FA alterations in the TPLs in the serum of patients with COVID-19 and their modification by treatment with Vit E. To evaluate the specific changes, it would be necessary to separately evaluate each of the fractions of the aforementioned FAAIPF, such as thin-layer chromatography followed by HPLC-MS. | [
"María Elena Soto",
"Linaloe Manzano-Pech",
"Verónica Guarner-Lans",
"Adrían Palacios-Chavarría",
"Rafael Ricardo Valdez-Vázquez",
"Raúl Martínez-Memije",
"Mohammed El-Hafidi",
"Félix Leao Rodríguez-Fierros",
"Israel Pérez-Torres"
] | https://doi.org/10.3390/cimb46070429 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
39057509_p0 | 39057509 | sec[0]/p[0] | 1. Introduction | 4.074219 | biomedical | Review | [
0.9794921875,
0.0026721954345703125,
0.0176544189453125
] | [
0.145263671875,
0.01383209228515625,
0.84033203125,
0.000507354736328125
] | Since the time of Florence Nightingale, the public image of nurses has been one of the main challenges for the profession . People’s perception of nursing often depends on their views regarding the roles, values, and professional activities of nurses, and the responsibilities that nurses have towards society . The nursing profession has evolved significantly in recent years , with nurses constituting a dominant part of the healthcare system both in terms of quantity and the nature of their roles . However, despite the rapid advancements in education, research, and clinical and organizational competence , the public image of nurses has not kept pace . The media image of nurses is a source of concern due to its impact on recruitment into the profession, patient satisfaction and quality of care, nurse motivation and job performance, quality of work life, intention to leave the profession, healthcare policies, and funding for nursing services . Although research plays a significant role, the public image of nurses is influenced by other factors, including mass communication, culture, stereotypes, and nurses’ self-esteem . Therefore, the scientific community has agreed on the importance of conducting studies that evaluate the public perception of nursing , as it has been shown that there is a direct correlation between the positive perception of the profession and the quality of nursing care . Since 2020, studies aimed at evaluating the image of nurses have significantly increased, recognizing the key role of nurses during the COVID-19 pandemic . With nurses being on the frontline alongside patients during the pandemic, the public’s perception on social media seems to portray an image of nurses that reflects the professionalism and values of the profession . It is no coincidence that nurses have been represented with artistic images depicting the values of courage and professional dedication in the service of life. The results of some Italian studies in 2023 showed an improvement in the public image compared to previous studies, probably due to the influence of the mass media and the pandemic experience. However, despite these results, the attractiveness of the nursing profession in Italy remains quite low . According to the 2023 Italian Health Report, to develop the territory according to the National Recovery and Resilience Plan (PNRR), between 40,000 and 80,000 nurses are needed, but finding them is currently difficult; the attractiveness of the profession is low, and only 1% of students choose this degree course compared to an average of 3% in other EU countries . In light of these data, the National Federation of Nursing Orders had proposed actions to the Italian government to address the nursing shortage, including improving postgraduate training with clinical specialization master’s degrees, greater recognition of nurses within organizations, and a remuneration system specific to the role . For these reasons, one of the long-term challenges for nursing is to assess and maintain a favorable public image that respects the utility and value of the profession . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
39057509_p1 | 39057509 | sec[0]/p[1] | 1. Introduction | 1.952148 | biomedical | Other | [
0.77978515625,
0.0032176971435546875,
0.2171630859375
] | [
0.06036376953125,
0.935546875,
0.0037479400634765625,
0.0005726814270019531
] | The Nursing Attitudes Questionnaire (NAQ) is an instrument that assesses people’s perceptions of the nursing profession . The NAQ was adapted by Toth et al. from a previous instrument developed by Hoskins . The validity and reliability of the instrument have been tested in previous studies . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
39057509_p2 | 39057509 | sec[0]/p[2] | 1. Introduction | 2.212891 | biomedical | Other | [
0.8203125,
0.00402069091796875,
0.1756591796875
] | [
0.1522216796875,
0.845703125,
0.0016355514526367188,
0.0005631446838378906
] | It is a Likert scale instrument composed of 30 items, with five points, where one means strongly disagree and five means strongly agree. The NAQ scores therefore range from 30 to 150 points, where higher scores indicate a more favorable attitude towards nursing care, while lower scores reflect a less positive perception. Seven items are recoded before statistical analysis . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999995 |
39057509_p3 | 39057509 | sec[0]/p[3] | 1. Introduction | 3.962891 | biomedical | Study | [
0.994140625,
0.0009350776672363281,
0.004985809326171875
] | [
0.99609375,
0.0021877288818359375,
0.0017709732055664062,
0.00010347366333007812
] | The instrument measures attitudes towards nurses using statements that reflect the roles of the professional, including values, responsibilities, characteristics of nurses/nursing, professionalism, and societal stereotypes. A panel of experts supported the content validity of this instrument, while construct validity was established using the contrastive group approach. Cronbach’s alpha ranged from 0.75 to 0.80 in previous studies . The original language instrument was tested among the population of nursing students, and the calculations were determined on each individual item and not by domain. The content validity for each domain was supported by a group of experts, who added 12 items to a previous instrument called the “Hoskins Questionnaire” . Neither in the study by Toth et al. nor in subsequent studies were the factor analysis calculations highlighted . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
39057509_p4 | 39057509 | sec[0]/p[4] | 1. Introduction | 1.962891 | biomedical | Study | [
0.5537109375,
0.0011119842529296875,
0.445068359375
] | [
0.9443359375,
0.054656982421875,
0.000732421875,
0.0003294944763183594
] | In Italy, the instrument has been tested with a sample from the entertainment world (VIP) , on high school students during orientation meetings for university access, and specifically to the Nursing Degree Course , and in the post-COVID-19 pandemic period on the Italian population from North to South Italy . Italian studies used the NAQ in its original form and, like previous studies , the areas were determined based on the work of a panel of experts and supported by internal consistency analysis. No factor analysis calculations were performed; only internal consistency was analyzed (α = 0.89) . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
39057509_p5 | 39057509 | sec[0]/p[5] | 1. Introduction | 1.801758 | other | Study | [
0.39892578125,
0.0014371871948242188,
0.599609375
] | [
0.91064453125,
0.08782958984375,
0.0010576248168945312,
0.0005574226379394531
] | The aim of this paper is to provide literature with an Italian instrument that evaluates the public image of the nursing profession as perceived by ordinary people who are not professionals. For this reason, interviews were conducted with Italian citizens using survey-like methods. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999995 |
39057509_p6 | 39057509 | sec[0]/p[6] | 1. Introduction | 1.895508 | biomedical | Study | [
0.7490234375,
0.0016317367553710938,
0.2496337890625
] | [
0.75,
0.24755859375,
0.0017461776733398438,
0.0006961822509765625
] | The finality is to validate the Italian version of the NAQ and test its psychometric properties on the Italian population. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
39057509_p7 | 39057509 | sec[1]/sec[0]/p[0] | 2.1. Translation Procedures | 3.150391 | biomedical | Study | [
0.986328125,
0.001007080078125,
0.01275634765625
] | [
0.99658203125,
0.0030117034912109375,
0.0002624988555908203,
0.00009036064147949219
] | To establish the content validity of the NAQ scale, a forward–back translation procedure was applied. The White and Elander criteria were used as in the pilot study . Firstly, the NAQ scale was translated into Italian and submitted to a panel of experts (5 nurses with expertise in nursing education and research) who compared the original English version of the scale with the Italian version and ensured the semantic and cultural consistency of the items. Secondly, an English lecturer translated the Italian version into English as a blind. Finally, the back-translated and the original instrument were compared by a native speaker. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p8 | 39057509 | sec[1]/sec[0]/p[1] | 2.1. Translation Procedures | 1.960938 | biomedical | Study | [
0.9580078125,
0.0016641616821289062,
0.040130615234375
] | [
0.96484375,
0.0311279296875,
0.0035037994384765625,
0.0004868507385253906
] | The reliability of the NAQ has been tested in previous studies . However, these studies used scores from the entire NAQ to compare demographic data or interventions. No factor analysis was performed to test the construct validity. It is unclear which items contribute to which factor or dimension of the concept, “attitude towards nursing care” . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
39057509_p9 | 39057509 | sec[1]/sec[1]/p[0] | 2.2. Sampling Procedures | 1.780273 | biomedical | Study | [
0.95751953125,
0.0016002655029296875,
0.040771484375
] | [
0.9775390625,
0.0216522216796875,
0.000579833984375,
0.0003979206085205078
] | Adults from heterogeneous professions were included in the study. In contrast with previous studies , the sampling was collected in Italy and the questionnaire was completed by citizens from the north to the south of the country. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999999 |
39057509_p10 | 39057509 | sec[1]/sec[2]/p[0] | 2.3. Sample Description | 2.121094 | biomedical | Study | [
0.97509765625,
0.0018215179443359375,
0.0229949951171875
] | [
0.99658203125,
0.0030269622802734375,
0.00023758411407470703,
0.00017070770263671875
] | A non-probabilistic sample of 564 individuals voluntarily participated in the research. The validation study included people interviewed in the post-pandemic period across the entire Italian territory. The data were extracted from a database of 1345 observations collected from 2017 to January 2023. However, to avoid biases contingent on the changed public perception of nurses engaged in the fight against COVID-19, only questionnaires from the post-pandemic period were considered. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p11 | 39057509 | sec[1]/sec[3]/p[0] | 2.4. Collection Procedures and Additional Variables | 1.59375 | biomedical | Other | [
0.82568359375,
0.0018863677978515625,
0.1722412109375
] | [
0.239501953125,
0.75830078125,
0.0011625289916992188,
0.0009527206420898438
] | The research project that activated the studies on the image of the nurse was authorized by the Unibo Bioethics Committee on 8 February 2017 prot. 13221. Sampling was collected on a voluntary basis after explaining the purpose of the studies. Anonymity is guaranteed, and there is no information in the database that can be traced back to the identity of the sample. Documents and access to the data were only granted to the author responsible for the research projects. The questionnaires were completed on an online platform in self-administration mode. The respondents were given ample time to reflect and answer the questions. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p12 | 39057509 | sec[1]/sec[4]/p[0] | 2.5. Statistical Methods | 2.179688 | biomedical | Study | [
0.94091796875,
0.0010051727294921875,
0.058197021484375
] | [
0.98095703125,
0.0181427001953125,
0.0005435943603515625,
0.0002371072769165039
] | Statistical analysis was conducted using SPSS 29.0, Jamovi 2.3.18, and Office 2003 Excel. The scores of items 4, 9, 15, 17, 19, 23, and 27 (7 items) in the “Stereotypes” domain were recoded prior to statistical analysis. The recoding scheme for the Likert scale scores was as follows: 5 = 1, 4 = 2, 3 = 3, 2 = 4, 1 = 5 . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
39057509_p13 | 39057509 | sec[1]/sec[4]/p[1] | 2.5. Statistical Methods | 3.181641 | biomedical | Study | [
0.99462890625,
0.0003886222839355469,
0.0049896240234375
] | [
0.99853515625,
0.0010709762573242188,
0.00019311904907226562,
0.00004607439041137695
] | In the first phase, descriptive statistics of the questionnaire on the characteristics of the sample were calculated, the normality of the distributions were related to each of the items, and the total questionnaire score was verified by calculating skewness and kurtosis indices . The significance of some socio-demographic variables was determined using the t -test. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p14 | 39057509 | sec[1]/sec[4]/p[2] | 2.5. Statistical Methods | 3.412109 | biomedical | Study | [
0.99169921875,
0.0002880096435546875,
0.00788116455078125
] | [
0.98583984375,
0.01372528076171875,
0.0004520416259765625,
0.0000807046890258789
] | Pearson’s correlation coefficient (r) was used to assess the degree of association between each item and the overall scale (item-to-total correlation). Acceptable values for this index (r) were considered to be greater than 0.30 . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p15 | 39057509 | sec[1]/sec[4]/p[3] | 2.5. Statistical Methods | 2.730469 | biomedical | Study | [
0.95849609375,
0.0007176399230957031,
0.04083251953125
] | [
0.99609375,
0.003162384033203125,
0.00045680999755859375,
0.00007665157318115234
] | Subsequently, to verify the internal consistency of the questionnaire, Cronbach’s alpha coefficient was calculated . To evaluate the contribution of each item to the reliability of the scale, the changes in alpha values with the item deleted were determined . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999999 |
39057509_p16 | 39057509 | sec[1]/sec[4]/p[4] | 2.5. Statistical Methods | 3 | biomedical | Study | [
0.92724609375,
0.0005021095275878906,
0.0721435546875
] | [
0.974609375,
0.0249176025390625,
0.00055694580078125,
0.00012218952178955078
] | Before proceeding with the factor analysis, tests for adequacy and sample size were conducted using the Kaiser–Meyer–Olkin (KMO) measure, accepting values > 0.60, and Bartlett’s test of sphericity, highlighting its significance . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
39057509_p17 | 39057509 | sec[1]/sec[4]/p[5] | 2.5. Statistical Methods | 2.777344 | biomedical | Study | [
0.96240234375,
0.0005450248718261719,
0.037017822265625
] | [
0.9638671875,
0.03546142578125,
0.0006570816040039062,
0.00020706653594970703
] | Exploratory factor analysis (EFA) was conducted with two objectives as follows: instrumental reduction by eliminating unnecessary items and identification of the main factors for data reduction. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p18 | 39057509 | sec[1]/sec[4]/p[6] | 2.5. Statistical Methods | 2.482422 | other | Study | [
0.370361328125,
0.0011157989501953125,
0.62841796875
] | [
0.98046875,
0.018218994140625,
0.000888824462890625,
0.0002269744873046875
] | The questionnaire was analyzed with the following four sections using orthogonal varimax rotation: 1. Role and Professionalism; 2. Stereotypes; 3. Values and Advocacy; 4. Motivation and Satisfaction. Internal consistency (α), sample adequacy (KMO), and the strength of the relationship between variables (Bartlett’s test of sphericity) were calculated for all sections. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
39057509_p19 | 39057509 | sec[1]/sec[4]/p[7] | 2.5. Statistical Methods | 3.167969 | biomedical | Study | [
0.99658203125,
0.00037217140197753906,
0.0029621124267578125
] | [
0.98779296875,
0.011688232421875,
0.0006227493286132812,
0.0001354217529296875
] | Spearman’s correlation coefficient (Rho) was used to determine the relationships between the summary variable and the research instrument. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
39057509_p20 | 39057509 | sec[2]/sec[0]/p[0] | 3.1. Demographic Characteristics of the Sample | 3.0625 | biomedical | Study | [
0.99072265625,
0.0034084320068359375,
0.00591278076171875
] | [
0.9990234375,
0.0010099411010742188,
0.00008893013000488281,
0.00010520219802856445
] | The sample consisted of 26.4% ( n = 149) males and 73.6% ( n = 415) females. The age group for 34.9% ( n = 197) was between 20 and 30 years, 20.7% ( n = 117) were between 31 and 40 years, 22.7% ( n = 128) were between 41 and 50 years, 14.9% ( n = 84) were between 51 and 60 years, and 6.0% ( n = 34) were between 61 and 70 years. Up to 51.4% ( n = 290) had a high school diploma, 28.9% ( n = 163) had a university degree, 11.0% ( n = 62) had a middle school degree, 7.1% ( n = 40) had a postgraduate degree, and 1.2% ( n = 7) had a primary school degree. Regarding employment, 34.2% ( n = 193) of the sample were civil servants, 18.8% ( n = 106) were private employees, 22.7% ( n = 128) were students, 11.0% ( n = 62) were self-employed, 3.7% ( n = 21) were unemployed, 4.1% ( n = 23) were retired, and 4.1% ( n = 23) were housewives. Approximately 46.5% ( n = 262) have had at least one hospital admission and 71.3% ( n = 402) have had contact with a nurse ( Table 1 ). | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p21 | 39057509 | sec[2]/sec[0]/p[1] | 3.1. Demographic Characteristics of the Sample | 3.890625 | biomedical | Study | [
0.9951171875,
0.0014476776123046875,
0.0032939910888671875
] | [
0.99951171875,
0.00034117698669433594,
0.00016057491302490234,
0.00006324052810668945
] | Before proceeding with the calculations to determine the psychometric properties of the instrument, a t -test was used to calculate any statistically significant differences in the items between the citizens who have had and those who have not had at least one hospital admission. The item, “Nurses are adequately paid for the work they do”, showed a significant difference ( p = 0.023). Both groups, although with a point < 3, expressed a mean of 2.63 ± 1.95 for the group with at least one admission versus 2.31 ± 1.293 for those who had never been hospitalized. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p22 | 39057509 | sec[2]/sec[1]/p[0] | 3.2. Psychometric Properties of the Instrument | 2.498047 | biomedical | Study | [
0.8330078125,
0.001361846923828125,
0.1656494140625
] | [
0.98876953125,
0.01016998291015625,
0.0007319450378417969,
0.0001518726348876953
] | The Cronbach’s alpha in the 30 items was 0.893 and varied between 0.88 and 0.89 among the factors identified in the theoretical structure of the NAQ . No changes in the internal consistency reliability were found after eliminating each item one by one. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999995 |
39057509_p23 | 39057509 | sec[2]/sec[1]/p[1] | 3.2. Psychometric Properties of the Instrument | 2.546875 | biomedical | Study | [
0.7529296875,
0.0014734268188476562,
0.2454833984375
] | [
0.99169921875,
0.007717132568359375,
0.00043892860412597656,
0.0001252889633178711
] | Skewness and kurtosis showed a normal distribution in the item responses in most items, and a weak tendency towards higher levels of agreement (mean score < 3.50) in the items 4, 9, 15, 17, 19 (Stereotypes domain), 18 (Role and Professionalism domain), 12, and 28 (Motivation and Satisfaction domain). With regard to these items, no statistical transformations were adopted because the skewness and kurtosis deviation were not critical and the methods used in the data analysis were not influenced by the data distribution . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
39057509_p24 | 39057509 | sec[2]/sec[1]/p[2] | 3.2. Psychometric Properties of the Instrument | 2.355469 | biomedical | Study | [
0.552734375,
0.0014276504516601562,
0.44580078125
] | [
0.98681640625,
0.0124969482421875,
0.00041031837463378906,
0.0001569986343383789
] | From Table 1 , it can also be observed that the item-to-total correlation index greatly exceeds 0.30 for all 30 items, indicating a high degree of correlation between each item and the overall scale ( p ≤ 0.001). The item with the lowest value (<0.50) is item 18, “Men make good nurses,” with a correlation of 0.496. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
39057509_p25 | 39057509 | sec[2]/sec[1]/p[3] | 3.2. Psychometric Properties of the Instrument | 2.193359 | biomedical | Study | [
0.73486328125,
0.0011224746704101562,
0.26416015625
] | [
0.9189453125,
0.07940673828125,
0.0012950897216796875,
0.0003933906555175781
] | The sample adequacy test (KMO) ranges from good (0.80–0.90) to excellent (>0.90) across all items. The numbering alongside the items in Table 2 respects the original sequencing of the original instrument ( Table 2 ). | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
39057509_p26 | 39057509 | sec[2]/sec[2]/p[0] | 3.3. Exploratory Factor Analysis | 4.023438 | biomedical | Study | [
0.99169921875,
0.0002313852310180664,
0.008026123046875
] | [
0.9990234375,
0.0009288787841796875,
0.0001652240753173828,
0.000029742717742919922
] | The NAQ was subjected to Exploratory Factor Analysis (EFA) using the principal axis extraction method. The number of factors to be extracted was chosen based on the scree plot method and the eigenvalue greater than 1.0 method . In the scree plot, component 1 recorded an eigenvalue of 10.226 with a variance percentage of 34.08%, component 2 had an eigenvalue of 5.002 and a variance of 16.67%, component 3 had an eigenvalue of 1.714 and a variance of 5.71%, and component 4 had an eigenvalue of 1.219 and a variance of 4.06%. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p27 | 39057509 | sec[2]/sec[2]/p[1] | 3.3. Exploratory Factor Analysis | 2.753906 | biomedical | Study | [
0.95166015625,
0.00054168701171875,
0.048004150390625
] | [
0.9619140625,
0.037322998046875,
0.0005521774291992188,
0.00018036365509033203
] | Exploratory factor analysis (EFA), with varimax rotation, showed through the Scree Plot, a four-factor model showing 53.9% variance in the scale . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p28 | 39057509 | sec[2]/sec[2]/p[2] | 3.3. Exploratory Factor Analysis | 3.300781 | biomedical | Study | [
0.98388671875,
0.0003807544708251953,
0.0155029296875
] | [
0.99072265625,
0.00910186767578125,
0.0003037452697753906,
0.00007617473602294922
] | The criteria for performing the factor analysis were a verified KMO of 0.930 and the Bartlett’s sphericity test showing a p -value of <0.001 (chi squared = 10,786 and df = 435) . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999999 |
39057509_p29 | 39057509 | sec[2]/sec[2]/p[3] | 3.3. Exploratory Factor Analysis | 2.220703 | biomedical | Study | [
0.8515625,
0.0011014938354492188,
0.1473388671875
] | [
0.95458984375,
0.0447998046875,
0.0005068778991699219,
0.0002665519714355469
] | There were six random eigenvalues from the parallel analysis that were greater than 1.0. For the NAQ-IV, an initial four-factor solution was chosen for better grouping of items along content dimensions, as parallel analysis tends to overestimate the number of extracted factors . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999995 |
39057509_p30 | 39057509 | sec[2]/sec[2]/p[4] | 3.3. Exploratory Factor Analysis | 3.287109 | biomedical | Study | [
0.99267578125,
0.0003323554992675781,
0.00676727294921875
] | [
0.99853515625,
0.0012340545654296875,
0.00018215179443359375,
0.00004571676254272461
] | EFA was performed using the varimax rotation method, and the correlation matrix showed correlations of more than |0.45| between most of the factors ( Table 3 ). | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
39057509_p31 | 39057509 | sec[2]/sec[3]/p[0] | 3.4. Confirmatory Factor Analysis | 1.866211 | biomedical | Study | [
0.7607421875,
0.0014486312866210938,
0.2379150390625
] | [
0.52587890625,
0.470458984375,
0.0029315948486328125,
0.000911712646484375
] | Confirmatory factor analysis (CFA) seems to confirm the structure based on the data collected. The numerical sequencing of the table respects the Italian version of the tool (NAQ-IV). | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p32 | 39057509 | sec[2]/sec[3]/p[1] | 3.4. Confirmatory Factor Analysis | 4.089844 | biomedical | Study | [
0.9892578125,
0.0002923011779785156,
0.010589599609375
] | [
0.9990234375,
0.0008463859558105469,
0.00018107891082763672,
0.000028967857360839844
] | The goodness-of-fit of the four-factor solution assessed in the CFA used several criteria as follows: chi squared/degrees of freedom (χ 2 /df), and root mean square error of approximation (RMSEA). The test for exact fit thus indicated an χ 2 = 2.567 ( p ≤ 0.001), SRMR 0.0939, RMSEA 0.0981 , TLI 0.777, and CFI 0.795. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999995 |
39057509_p33 | 39057509 | sec[3]/p[0] | 4. Discussion | 3.15625 | biomedical | Study | [
0.92333984375,
0.0015249252319335938,
0.074951171875
] | [
0.99853515625,
0.0010156631469726562,
0.0005135536193847656,
0.00008803606033325195
] | This study contributes to the literature by examining an Italian instrument for assessing the public image of nurses. The study revealed that participants had a positive image of nurses, as highlighted in the literature . The investigated areas included the role and professionalism of nurses in socio-health contexts, stereotypes, values, and advocacy, and the motivations and satisfactions perceived by nursing professionals operating in Italy. Regarding the stereotype domain, the study showed negative correlations with the other three areas. This demonstrates the positive perception that citizens have in light of the evolving competencies of the nursing profession, which was also promoted by mass media during the pandemic period . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 1 |
39057509_p34 | 39057509 | sec[3]/p[1] | 4. Discussion | 1.671875 | other | Other | [
0.446533203125,
0.003612518310546875,
0.5498046875
] | [
0.01332855224609375,
0.98583984375,
0.000720977783203125,
0.00031185150146484375
] | It was necessary to validate a useful tool to assess the public image of nurses in Italy to monitor how territorial policies can positively influence the attractiveness of the profession for young people , better patient satisfaction and quality of nursing care, and improved quality of work life . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
39057509_p35 | 39057509 | sec[3]/p[2] | 4. Discussion | 1.685547 | other | Other | [
0.389404296875,
0.00167083740234375,
0.60888671875
] | [
0.07037353515625,
0.927734375,
0.0012903213500976562,
0.0004756450653076172
] | The Italian version of the NAQ, named NAQ-IV, appears to be a valid instrument for investigating the perception that ordinary people have of the image of nurses. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
39057509_p36 | 39057509 | sec[3]/p[3] | 4. Discussion | 4.085938 | biomedical | Study | [
0.99560546875,
0.00041961669921875,
0.004138946533203125
] | [
0.99951171875,
0.00023639202117919922,
0.0003249645233154297,
0.000037610530853271484
] | The psychometric characteristics of the NAQ-IV show a four-factor aggregation and good internal consistency of the items. In the past, other studies have used the NAQ by reducing the items and extrapolating factors. In 2016, Hoeve et al. used the questionnaire on a population of nursing students in the Netherlands. The research aimed to evaluate the orientation and attitudes of a cohort of first-year students towards nursing at the beginning of the educational program. To this end, the authors reduced the NAQ items from 30 to 18 and extrapolated two factors from the questionnaire, namely “Nursing Agency” (14 items α = 0.74) and “Advocacy and Empathy” (4 items α = 0.63). In this study, Confirmatory Factor Analysis (CFA) showed a fit with X 2 = 3.69; CFI = 0.90; RMSEA = 0.046; α = 0.79. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
39057509_p37 | 39057509 | sec[3]/p[4] | 4. Discussion | 2.871094 | biomedical | Study | [
0.93505859375,
0.001010894775390625,
0.063720703125
] | [
0.990234375,
0.0063934326171875,
0.003208160400390625,
0.00015687942504882812
] | From 2017 to 2023, studies were conducted in Italy using the NAQ. These studies aimed to evaluate the perception of ordinary people towards the image of nurses and nursing care. The authors focused on an overall result of the 30 items of the NAQ and on the areas named by Toth et al. in 1998. The areas indicated by Toth et al. mentioned the number of items per area in the article without clearly indicating which questions they were. Furthermore, the study did not include factor analysis calculations. For this reason, in the Italian studies, the content validity of the areas suggested by Toth et al. was supported by a panel of experts who reviewed the NAQ questions and assigned the most appropriate items for each area. No factor analysis calculations were performed, only overall internal consistency calculations and correlation coefficients between areas . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p38 | 39057509 | sec[3]/p[5] | 4. Discussion | 1.912109 | biomedical | Study | [
0.77880859375,
0.0014743804931640625,
0.219482421875
] | [
0.80224609375,
0.1876220703125,
0.0092315673828125,
0.0008339881896972656
] | Therefore, the NAQ-IV has only one comparative study, that of Hoeve et al. , which, although it presented factor analysis calculations, used the NAQ with reduced items. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p39 | 39057509 | sec[3]/p[6] | 4. Discussion | 4.117188 | biomedical | Study | [
0.9970703125,
0.000736236572265625,
0.0020732879638671875
] | [
0.9951171875,
0.00048661231994628906,
0.00443267822265625,
0.00008505582809448242
] | The NAQ-IV, although it presents 14 items in the first factor, shows no evidence of similarity with the first factor explored by Hoeve et al. as their study did not report the constituent items. However, the methodology for naming the areas in the Italian version of the NAQ followed the study by Hoeve et al. . A team of four researchers examined the NAQ items to verify that their formulation reflected the concept measured—the image of nurses and the attitude of the sample towards nursing. The specific meaning of each item was examined to establish face validity. The identified domains are confirmed by previous studies on the NAQ, phylogenesis, and the organizational, educational, and care models of the nursing profession. The areas “Role and Professionalism” and “Stereotypes” express the concepts highlighted by the study of Toth et al. as well as Bolan and Grainger , while “Values and Advocacy” refers to the extent to which nurses speak and act for patients, specifically addressing unmet patient needs, making it a value for the profession to satisfy these needs . Regarding nurse motivation and satisfaction, a significant intrinsic relationship between these two elements was found to improve nursing care and its related image . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p40 | 39057509 | sec[3]/p[7] | 4. Discussion | 4.089844 | biomedical | Study | [
0.99658203125,
0.0006184577941894531,
0.0026454925537109375
] | [
0.9990234375,
0.000270843505859375,
0.0004253387451171875,
0.00004279613494873047
] | The Cronbach’s alpha coefficient on the total NAQ-IV scale used in interviews with the general public recorded a value of 0.89, with a range from 0.88 to 0.89. These results seem consistent with previous studies where the sample consisted only of nursing students. In fact, research on Canadian students showed an alpha variation from 0.80 to 0.82 , while Toth et al.’s study found a range from 0.75 to 0.80 . Therefore, the NAQ-IV appears to be a reliable instrument for assessing the perception of the image of nurses and nursing care among the general public. Furthermore, there seems to be no indication to eliminate any item based on the loading of the EFA elements . A good variability of responses was found, therefore it can be stated that the formulation of the items does not generate a preferred response towards higher or lower levels of agreement, which could confirm the assumption of variability of the Likert scale . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
39057509_p41 | 39057509 | sec[4]/p[0] | 5. Limits | 2.333984 | biomedical | Study | [
0.9052734375,
0.0011892318725585938,
0.09375
] | [
0.994140625,
0.005157470703125,
0.00035643577575683594,
0.00011217594146728516
] | A strength of the study is the use of an online platform for the questionnaire, which allowed participants from all over the country to express their opinions. However, self-completion of a digital questionnaire did not allow us to reach citizens without smartphones or those who do not use social media. Another limitation is determined by the sample size and consequently by the sample selection method. It was not possible to randomize the participants in the study, and the sample is heterogeneous in sociodemographic characteristics, with even significant percentage differences. Regarding the instrument, further studies are recommended to evaluate its reliability, especially in the case of changes in the professional profile or the Italian socio-healthcare welfare system. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p42 | 39057509 | sec[5]/p[0] | 6. Conclusions | 4.070313 | biomedical | Study | [
0.9970703125,
0.0005826950073242188,
0.0022678375244140625
] | [
0.99951171875,
0.00035190582275390625,
0.00028061866760253906,
0.000055670738220214844
] | This study demonstrated a satisfactory psychometric property in the Italian version of the Nursing Attitudes Questionnaire. With respect to previous validation works, the NAQ-IV investigated the perception of the image of the nursing profession and nursing care on a population that was not exclusively student but heterogeneous in terms of profession, culture, and age. Specifically, the NAQ-IV structured four factors investigating the respondents’ perceived role, professionalism, stereotypes, values, advocacy, motivation and satisfaction with the nursing profession. The instrument could be useful to investigate how society perceives the role and functions of the nurse and what value they attach to the profession. In previous Italian studies, the NAQ has provided significant insights into the motivations that make the profession unattractive to young people who need to undertake education to enter the workforce . | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p43 | 39057509 | sec[5]/p[1] | 6. Conclusions | 2.484375 | biomedical | Other | [
0.67822265625,
0.0025806427001953125,
0.319091796875
] | [
0.11962890625,
0.87255859375,
0.007266998291015625,
0.0005068778991699219
] | The NAQ-IV could be an interesting instrument to assess the internationally perceived image and nursing care among ordinary people. An international multi-center approach could therefore be useful to confirm the theoretical framework in the structure of the NAQ-IV. For future research, longitudinal studies are recommended to monitor changes in public perception over time, particularly in response to policy changes and societal shifts. Additionally, expanding this research internationally could provide comparative insights and further validate the NAQ-IV in different cultural contexts. Practical implications include the potential use of the NAQ-IV by healthcare organizations and policymakers to assess and improve the public image of nursing, thereby enhancing the profession’s attractiveness and addressing the current nursing shortage. | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057509_p44 | 39057509 | sec[5]/p[2] | 6. Conclusions | 2.3125 | biomedical | Other | [
0.8095703125,
0.002017974853515625,
0.1884765625
] | [
0.1785888671875,
0.8134765625,
0.0076141357421875,
0.0005044937133789062
] | In summary, the NAQ-IV is a valuable instrument for investigating the perception of the nursing profession among the general public in Italy. Its use can contribute significantly to understanding and improving the factors that influence the public image of nursing, ultimately leading to better recruitment, retention, and overall quality of nursing care. Further research and international collaboration are recommended to expand the utility and applicability of the NAQ-IV in diverse settings (“see Appendix A ”). | [
"Ivan Rubbi",
"Luana Conte",
"Gianandrea Pasquinelli",
"Paola Ferri",
"Elsa Vitale",
"Roberto Lupo",
"Valeria Cremonini"
] | https://doi.org/10.3390/healthcare12141366 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057445_p0 | 39057445 | sec[0]/p[0] | 1. Introduction | 4.0625 | biomedical | Other | [
0.9951171875,
0.00040984153747558594,
0.0045318603515625
] | [
0.285400390625,
0.53564453125,
0.178466796875,
0.0008044242858886719
] | Sonication or ultrasonication is the application of ultrasound energy to a sample, which most often consists of a fluid with dispersed particles. There are two main ways for sonication, namely, by using an ultrasonic bath or a probe sonicator. In the first mode, the fluid in a vessel is set in a water-containing ultrasonic bath; in the second, the ultrasonic probe is immersed in the fluid of interest. Applications of ultrasound may be roughly divided into low-power (<1 W/cm 2 ) and high-frequency (>100 kHz) regimes, as well as in high-power (>1 W/cm 2 ) and low-frequency (20–100 kHz) regimes, being the first mainly used for non-destructive analysis or materials characterization, while the second is used in industrial processes as well as to produce chemical reactions and changes in the microstructure of materials . | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057445_p1 | 39057445 | sec[0]/p[1] | 1. Introduction | 4.054688 | biomedical | Review | [
0.994140625,
0.0004639625549316406,
0.00543975830078125
] | [
0.279052734375,
0.315673828125,
0.404052734375,
0.0010843276977539062
] | According to the Royal Society of Chemistry , propagation of ultrasonic waves (typically >20 kHz) in a liquid medium results in agitation along with alternating high-pressure (compression) and low-pressure (rarefaction) cycles. During rarefaction, high-intensity sonic waves create small vacuum bubbles or voids in the liquid, which then collapse violently (cavitation) during compression, creating very high local temperatures and stresses. Thus, prolonged high-intensity sonication may produce chemical reactions in a sample. High-intensity sonication has been exploited in many applications, including cleaning, drilling, soldering, chemical processes, emulsification, deagglomeration, extraction, cell disruption , dispersion of nanoparticles in nanofluids and others, as those found in food science and processing . | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057445_p2 | 39057445 | sec[0]/p[2] | 1. Introduction | 4.234375 | biomedical | Study | [
0.99853515625,
0.00034165382385253906,
0.0012302398681640625
] | [
0.98779296875,
0.0003314018249511719,
0.01190185546875,
0.00009530782699584961
] | An application of sonication of particular interest to this work is the possible manipulation or tailoring of the microstructure of complex fluids, including gels. Gels appear in many everyday products, such as cosmetics, pharmaceuticals, detergents, coatings and foods, among many others. Therefore, tuning the flow or rheological properties of gels using ultrasound may be of practical relevance. Interestingly, scarce work has been conducted to understand the gel structural changes and its concomitant rheological behavior arising from sonication. In this regard, Seshadri et al. studied the effect of high-intensity ultrasound (40 W) at various times on the rheological and optical properties of high-methoxyl pectin (HMP) dispersions. These authors found that ultrasonically pretreated pectin dispersions formed weaker gels with increasing sonication power and time and resulted in more transparent gels. The results were attributed to an overall reduction in the average molecular weight of pectin due to cavitational effects. Rajabali et al. reported degradation of hydrogels made from acrylic acid and acrylamide; in this case, degradation was inferred from a decrease in the viscosity of the hydrogel with sonication time. Later, Prajapat and Gogate reported depolymerization of a polyacrylic acid solution submitted to ultrasound irradiation. In this case, depolymerization was deduced from a reduction in the intrinsic viscosity of the solution with sonication time. Zheng et al. also analyzed the effects of sonication at different powers (120, 240, 360 and 480 W) on the rheological properties of HMP dispersions and showed that their viscosity was reduced significantly with increasing sonication power and time; meanwhile, the overall pseudoplastic behavior of the gel was retained. Zheng et al. suggested that the cavitation effect damaged the structure of HMP as ultrasonic power increased, leading to a significantly decreased strength of the gel. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999994 |
39057445_p3 | 39057445 | sec[0]/p[3] | 1. Introduction | 4.109375 | biomedical | Study | [
0.9990234375,
0.00018286705017089844,
0.0008540153503417969
] | [
0.998046875,
0.0002644062042236328,
0.0016841888427734375,
0.0000432133674621582
] | Recently, Gibaud et al. introduced what they called “rheoacoustic” gels; that is, colloidal gels sensitive to ultrasonic vibrations. These authors used a combination of rheological and structural characterization to evidence and quantify a strong softening, including decreased yield stress and accelerated shear-induced fluidization, in three different colloidal gels submitted to ultrasonic vibrations (with submicron amplitude and frequencies in the range between 20 and 500 kHz). The softening was attributed to micron-sized cracks within the gel network, which could or could not fully heal, depending on the acoustic intensity, once vibrations are turned off. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
39057445_p4 | 39057445 | sec[0]/p[4] | 1. Introduction | 4.3125 | biomedical | Study | [
0.9990234375,
0.00035953521728515625,
0.0005984306335449219
] | [
0.99853515625,
0.0002465248107910156,
0.0009288787841796875,
0.00006729364395141602
] | The purpose of this work is twofold; the first one is to understand the effects of high-power sonication on the molecular characteristics of Carbopol ® and its rheological behavior in microgels. The second is to explore the possibility of manipulation or tailoring the microstructure of Carbopol ® and its rheological behavior in dispersions and microgels in particular, as well as complex fluids, in general, by systematic high-power ultrasound irradiation. Carbopol ® polymers are used in a variety of applications encompassing the cosmetics, pharmaceutical, paint and food industries as a thickening, gelling, suspending, dispersing and stabilizing agent. Thus, the effects of sonication time at a fixed power on the molecular characteristics of Ultrez 10 and its rheological behavior in a 0.25 wt.% dispersion in bi-distilled water and the resulting microgel after neutralization were analyzed by rheometry, molecular weight measurements via static light scattering (SLS), Fourier transform infrared (FTIR) spectroscopy and confocal microscopy. The precursor dispersion and the microgel were sonicated in a commercial ultrasound bath at constant power at various times. We observed a softening of the microgel microstructure consisting of a systematic decrease in its shear modulus, yield stress and viscosity with increasing sonication time, while the Herschel–Bulkley behavior was maintained. SLS measurements evidenced a reduction in M w of polyacrylic acid with sonication time. Separately, FTIR measurements indicate that sonication produces scission in the C-C links of the Ultrez 10 backbone, which results in chains with the same chemistry but lower molecular weight. Finally, confocal microscopic measurements revealed a concomitant diminution of the size of the microsponge domains resulting from a reduction in the molecular weight of polyacrylic acid with sonication time. Overall, results in this work indicate that both the microstructure and rheological behavior of microgels, in particular, and complex fluids in general, may be manipulated or tailored by high-power ultrasonication. Special interest may be paid to naturally occurring or synthetic polymers whose high molecular weight results in high-viscosity solutions and gels that limit their applications. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
39057445_p5 | 39057445 | sec[1]/sec[0]/p[0] | 2.1. Rheological Behavior of Non-Sonicated and Sonicated Microgels: Small Amplitude Oscillatory Shear Measurements | 3.912109 | biomedical | Study | [
0.998046875,
0.00019752979278564453,
0.0017805099487304688
] | [
0.9990234375,
0.0006380081176757812,
0.00024962425231933594,
0.000044465065002441406
] | To assess the changes in rheological behavior of the Ultrez 10 microgels due to ultrasound treatment, we performed oscillatory shear and rotational steady shear measurements. We first discuss the viscoelastic response in small amplitude oscillatory shear (SAOS) measurements and, afterward, the steady shear behavior of the microgels. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
39057445_p6 | 39057445 | sec[1]/sec[0]/p[1] | 2.1. Rheological Behavior of Non-Sonicated and Sonicated Microgels: Small Amplitude Oscillatory Shear Measurements | 4.25 | biomedical | Study | [
0.9990234375,
0.00037026405334472656,
0.0007333755493164062
] | [
0.99951171875,
0.00014650821685791016,
0.0003540515899658203,
0.00005346536636352539
] | Figure 1 a shows the absolute value of the complex shear modulus (| G* |) measured in stress amplitude sweeps at an angular frequency ( ω ) of 6.28 rad/s for the non-sonicated, SM0, and sonicated microgels samples, namely, SM60, SM120 and SM180 (the number in the labels represents the sonication time in minutes). Clearly, |G*| decreases with increasing the sonication time; its value in the linear viscoelastic region (LVR) decreases ~25%, from about 192 Pa for SM0 up to 159 Pa for SM180, evidencing a weakening or softening of the microgel microstructure due to the imposed ultrasound irradiation. Figure 1 b indicates that the softening of the microgel microstructure can be attributed to a decrease in its elastic response or elastic modulus ( G′ ) since the loss modulus ( G″ ) barely changes in the LVR with increasing the sonication time. In addition, the limit of the LVR and the crossover point between G′ and G″ decrease with increasing sonication time, which indicates that ultrasound treatment promotes anticipated fluidization. Lastly, Figure 1 c shows the frequency sweep for the microgel with different sonication times (the complex viscosity η* is included for completeness). Note that the value of the G′ / G″ ratios for different sonication times is of the order of ten or higher in the range of frequency analyzed, indicating that the 0.25 wt.% Ultrez 10 microgel remains a strong gel for the periods of irradiation in this work. On its side, η* , which is a more representative parameter for fluid-like samples and indicates the overall resistance to shear deformation, decreases systematically with sonication time. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057445_p7 | 39057445 | sec[1]/sec[1]/p[0] | 2.2. Rheological Behavior of Non-Sonicated and Sonicated Microgels: Steady Shear Measurements | 4.164063 | biomedical | Study | [
0.9970703125,
0.00041294097900390625,
0.002613067626953125
] | [
0.99951171875,
0.00013625621795654297,
0.00026226043701171875,
0.00003910064697265625
] | The flow curves of the microgel for different sonication times obtained under steady shear measurements are shown in Figure 2 , which includes the flow curves for SM0 and SM180 obtained in up and down shear stress cycles. First, it can be seen that SM0 and SM180 up and down flow curves superpose very well, respectively, indicating that the microgel is originally non-thixotropic and that sonication does not induce thixotropy. The same behavior was observed for all up and down flow curves . Also, as the share rate tends to zero, all flow curves extrapolate to a critical shear stress value, i.e., the yield stress of the microgels. Irrespective of the sonication time, they are all very well described by the H-B constitutive model, σ = σ y + m γ ˙ n , where σ is the shear stress, σ y is the yield stress, m is the consistency index, γ ˙ is the shear rate, and n is the shear rate sensitivity index, in agreement with previous reports for similar non-sonicated microgels . The H-B parameters for the microgels with different sonication times appear in Table 1 . | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
39057445_p8 | 39057445 | sec[1]/sec[1]/p[1] | 2.2. Rheological Behavior of Non-Sonicated and Sonicated Microgels: Steady Shear Measurements | 4.167969 | biomedical | Study | [
0.99755859375,
0.0002808570861816406,
0.00199127197265625
] | [
0.99951171875,
0.00015532970428466797,
0.0002586841583251953,
0.00003129243850708008
] | A significant decrease is observed, however, in the consistency index and yield stress of the microgel, that is, the first in an exponential way and the second linearly with increasing sonication time . Regarding the power–law or shear-thinning index of the microgel, this remains almost constant, with a more significant variation for SM180. This anomalous behavior is evidenced in Figure 3 b, where the different flow curves have been superposed by plotting σ / σ y as a function of the shear rate (see references ). Note that the SM180 flow curve departs from the superposed ones, indicating a dramatic change in the gel microstructure at long sonication times. Gutowski et al. interpreted different scaling among low- and high-concentration Ultrez 10 microgels as a signal of a meaningful change in the mesostructure of the materials, which agrees with the result in this work (see discussion in Section 2.5 below). | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
39057445_p9 | 39057445 | sec[1]/sec[1]/p[2] | 2.2. Rheological Behavior of Non-Sonicated and Sonicated Microgels: Steady Shear Measurements | 4.097656 | biomedical | Study | [
0.99853515625,
0.00019693374633789062,
0.00142669677734375
] | [
0.9990234375,
0.00028824806213378906,
0.0005645751953125,
0.000038504600524902344
] | The softening of the microgel microstructure and its nearly constant pseudoplastic behavior upon submission to sonication is consistent with previous reports for other gel systems . From X-ray scattering measurements in their colloidal gels during sonication, Gibaud et al. attributed this softening to micron-sized cracks within the gel network; these authors concluded that the gel network is fractured by ultrasonic vibrations and suggested that a more complete picture of the gel microstructure remained to be obtained. In Section 2.4 and Section 2.5 , we provide such a picture based on measurements of changes in the molecular characteristics of Ultrez 10 after sonication and confocal microscopy. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057445_p10 | 39057445 | sec[1]/sec[2]/p[0] | 2.3. Rheometry of the Sonicated Ultrez 10 Dispersion and Its Microgel | 4.207031 | biomedical | Study | [
0.9990234375,
0.0003459453582763672,
0.0004296302795410156
] | [
0.99951171875,
0.00016832351684570312,
0.0002281665802001953,
0.00005358457565307617
] | In a different experiment to assess ultrasound irradiation-induced damage of the molecular structure of polyacrylic acid, we sonicated a 0.25 wt.% Ultrez 10 dispersion for 180 min (SD180) before proceeding to neutralization to form the microgel (SDM180). Figure 4 displays the steady-state flow curve of such dispersion before and after sonication. Both flow curves exhibit a slight non-Newtonian behavior characterized by power–law relationships ( σ = m γ ˙ n where σ is the shear stress, m is the consistency index, γ ˙ is the shear rate, and n is the shear rate sensitivity index). It can be observed that SD180 is a little less viscous than the non-sonicated one (SD0), as expected, because of possible ultrasound damage on the Ultrez 10 macromolecules, which would result in a decrease in its M w (see discussion below). Concomitantly, a softening effect of the microgel microstructure is expected. Measurements of the pH at the same temperature in the dispersion before and after sonication were 2.40 ± 0.03, which indicates that ultrasound treatment does not influence the amount of ionized carboxyl groups in the dispersion. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
39057445_p11 | 39057445 | sec[1]/sec[2]/p[1] | 2.3. Rheometry of the Sonicated Ultrez 10 Dispersion and Its Microgel | 4.179688 | biomedical | Study | [
0.9990234375,
0.00026154518127441406,
0.0007777214050292969
] | [
0.99951171875,
0.0001722574234008789,
0.00017333030700683594,
0.00003898143768310547
] | Figure 5 a,b show the stress amplitude sweep at an angular frequency ( ω ) of 6.28 rad/s and the frequency sweep at 3 Pa, respectively, for the microgel (SDM180) obtained from the SD180 dispersion . The slight decrease in the G′ value is apparent for SDM180 in comparison with the SM180 sample, while the G″ value does not change. If ultrasound irradiation breaks polyacrylic acid macromolecules, the small decrease in G’ could be attributed to the formation of the SDM180 microgel from shorter molecules, i.e., with reduced molecular weight, leading to a slightly softer microgel structure than the SM180 microgel, which was composed of raw Ultrez 10. This result would agree with reports suggesting that stronger hydrogels result from increasing the degree of cross-linking and/or the molecular weight of the polymer . | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999999 |
39057445_p12 | 39057445 | sec[1]/sec[3]/p[0] | 2.4. Molecular Weight Measurements and FTIR of Ultrez 10 before and after Sonication | 4.214844 | biomedical | Study | [
0.99951171875,
0.000164031982421875,
0.0005202293395996094
] | [
0.98388671875,
0.003658294677734375,
0.0121917724609375,
0.00013077259063720703
] | Molecules dissolved in water can undergo pyrolysis and free radical attack when submitted to sonication . Also, macromolecules may be broken in their main chain due to sonication . The exact mechanism leading to chain scission is still not fully clear. One of the most accepted theories is that the shear forces generated by the rapid motion of the solvent on cavitation collapse are responsible for the breakage of the chemical bonds within the polymer . Another mechanism suggests, however, that there is an elongational field, rather than a shear field, during bubble collapse . In any event, bond scission occurs near the center of gravity of the macromolecules due to the high shear/elongation rates generated in the process. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057445_p13 | 39057445 | sec[1]/sec[3]/p[1] | 2.4. Molecular Weight Measurements and FTIR of Ultrez 10 before and after Sonication | 4.15625 | biomedical | Study | [
0.99951171875,
0.0002340078353881836,
0.0004432201385498047
] | [
0.99951171875,
0.00012218952178955078,
0.00047326087951660156,
0.000044345855712890625
] | Different authors have reported the degradation of polymer molecules when submitted to sonication. For example, Schittenhelm and Kulicke used ultrasonic degradation to create a homologous series of molar masses for establishing structure–property relationships in cellulose derivatives. These authors reported a diminution of molecular mass and polydispersity for hydroxyethylsulfoethyl cellulose with increasing the sonication time. More recently, Zhong et al. reported a decrease in the average molecular weight of schizophyllan and degradation products with a narrower molecular weight distribution after ultrasonic treatment. Also, the original non-Newtoninan shear-thinning behavior of untreated schizophyllan changed to a Newtonian one for the resulting fractions. To investigate the effect of ultrasound on the molecular structure of Ultrez 10 and its effect on microgel formation in this work, weight-average molecular weight ( M w ) measurements using static light scattering (SLS) and Fourier transform infrared spectroscopy (FTIR) were performed on the raw and sonicated polymer as shown below. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999995 |
39057445_p14 | 39057445 | sec[1]/sec[3]/p[2] | 2.4. Molecular Weight Measurements and FTIR of Ultrez 10 before and after Sonication | 4.164063 | biomedical | Study | [
0.998046875,
0.00023651123046875,
0.0018100738525390625
] | [
0.99951171875,
0.0002391338348388672,
0.00014388561248779297,
0.000027835369110107422
] | To determine the M w by SLS, the refractive index, n , of Ultrez 10 dispersions is measured as a function of its concentration, c ; the results are presented in Table 2 and plotted in Figure 6 a, respectively, for the SD0 and SD180 dispersions. The d n /d c values for each sample are obtained by linear fitting of the data, and the resulting equations are embedded in the Figure 6 a. These values are used to calculate the optical constant, K , which is necessary to obtain the Kc / R θ values, also presented in Table 2 and plotted in Figure 6 b versus c . The Rayleigh’s ratios, R θ , are calculated using the refractive indexes of water and toluene as well as the Rayleigh’s ratio of toluene. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057445_p15 | 39057445 | sec[1]/sec[3]/p[3] | 2.4. Molecular Weight Measurements and FTIR of Ultrez 10 before and after Sonication | 4.1875 | biomedical | Study | [
0.9990234375,
0.00024044513702392578,
0.0008068084716796875
] | [
0.99951171875,
0.0002111196517944336,
0.00018548965454101562,
0.00003606081008911133
] | In Figure 6 b, the dotted lines indicate the fittings to the Debye equation for SD0 and SD180. M w and A 2 are calculated from the ordinate to the origin and the slope of each linear relationship for SD0 and SD180 samples, respectively; the resulting values are reported in Table 3 . Clearly, the lowest M w corresponds to the SD180 sample, which is less than half the value corresponding to SD0; this reflects the effect of ultrasound treatment on the molecular structure of Ultrez 10. Interestingly, A 2 changes from positive for SD0 to negative for SD180, indicating that polymer-solvent interactions are favored before sonication; meanwhile, polymer–polymer interactions are promoted after sonication . | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057445_p16 | 39057445 | sec[1]/sec[3]/p[4] | 2.4. Molecular Weight Measurements and FTIR of Ultrez 10 before and after Sonication | 4.378906 | biomedical | Study | [
0.99951171875,
0.0004050731658935547,
0.00027251243591308594
] | [
0.9990234375,
0.00021767616271972656,
0.0006709098815917969,
0.00010836124420166016
] | The change in sign in A 2 for the sonicated polymer has also been related to a change in the chemical structure of the macromolecule due to depolymerization induced by prolonged periods of sonication . Figure 7 shows the Fourier transform infrared (FTIR) spectra of the lyophilized Ultrez 10 obtained from the SD0 and SD180 dispersions, respectively. For both samples, the peaks centered around 1705 and 1240 cm −1 , corresponding to the stretching of C=O and C-O bonds, respectively, along with the broad band from 3700 to 2400 cm −1 , indicating the presence of carboxylic groups. In particular, the small band between 2700 and 2400 cm −1 indicates dimer formation (overtone) or hydrogen bonding, which is characteristic of the polyacrylic acid in its solid (powder) state. In addition, the peaks located at low wavenumbers represent the wagging of C-H, which indicates the presence of C=C. Thus, the increase in the height of these peaks for SD180 suggests the scission of the C-C links in the backbone and the concomitant formation of C=C bonds at the ends of the new shorter and less polar polymer chains, which is consistent with the reduction in the molecular weight of Ultrez 10 and the change in sign of A 2 . These results are consistent with previous reports on the effect of sonication on the molecular structure of other water-soluble polymers . In addition, the reduction in the M w of the Ultrez 10 in the aqueous solutions and microgels, as well as their change in the rheological properties, agree well with that induced by ultrasound treatment for schizophyllan , water-soluble polymers and sodium alginate . | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999999 |
39057445_p17 | 39057445 | sec[1]/sec[3]/p[5] | 2.4. Molecular Weight Measurements and FTIR of Ultrez 10 before and after Sonication | 4.183594 | biomedical | Study | [
0.99951171875,
0.00029015541076660156,
0.00038814544677734375
] | [
0.99951171875,
0.0001729726791381836,
0.0002429485321044922,
0.00005042552947998047
] | On the other hand, Figure 8 shows the FTIR spectra of the sonicated (SD180) and non-sonicated (SD0) aqueous dispersions, which appear remarkably well superimposed. The broad band from 3700 to 2900 cm −1 , along with the peak centered at 1700 cm −1 attributed to O-H and C=O stretchings, respectively, are characteristic of carboxylic acid groups present along the backbone of polyacrylic acid. More importantly, the lack of a band for both SD0 and SD180 samples from 2800 to 2500 cm −1 , typical of carboxylic acids in their solid and liquid state, is indicative of complete dissociation of the carboxylic acid groups , which is consistent with the pH = 2.40 ± 0.03 measured for both the SD0 and SD180 samples. Thus, this result suggests that the softening of the microgel may be attributed only to a decrease in the molecular weight of Ultrez 10 macromolecules due to depolymerization occurring in their main backbone. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
39057445_p18 | 39057445 | sec[1]/sec[3]/p[6] | 2.4. Molecular Weight Measurements and FTIR of Ultrez 10 before and after Sonication | 4.1875 | biomedical | Study | [
0.9990234375,
0.0003173351287841797,
0.0008897781372070312
] | [
0.99951171875,
0.00013816356658935547,
0.0002715587615966797,
0.00003898143768310547
] | A separate test of similarity between SM180 and SDM180 microgels is obtained from steady-state flow measurements. Figure 9 shows the up and down flow curves of the SDM180 microgel as compared to SM0 and SM180 ones. First, note that the SDM180 and SM180 exhibit almost the same flow behavior, i.e., they are very well described by the same H-B model. Then, the up and down SDM180 flow curves superimpose with the corresponding SM180, indicating that ultrasound treatment before gel formation does not induce thixotropy either. Interestingly, this is consistent with the viscous response obtained from the oscillatory measurements in Figure 5 , where the G ″ values are similar for the SM180 and SDM180 microgels. Thus, these results further demonstrate that sonication of the precursor dispersion (that results in the SDM180 microgel) or the already formed gel (SM180) produces softer microgels as compared to the non-sonicated one, with SM180 and SDM180 showing similar shear rheological properties . | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999999 |
39057445_p19 | 39057445 | sec[1]/sec[3]/p[7] | 2.4. Molecular Weight Measurements and FTIR of Ultrez 10 before and after Sonication | 3.763672 | biomedical | Study | [
0.998046875,
0.00021278858184814453,
0.0016269683837890625
] | [
0.99853515625,
0.0009775161743164062,
0.00020122528076171875,
0.00004881620407104492
] | Although our study was carried out at constant power, it is expected that increasing the sonication power and time (this last implicitly introduces more energy) results in a decrease in the rheological properties. There may be a limit to this decrease, provided there is a limiting degree of depolymerization . Also, further input of energy by increasing power and time of sonication may result in the collapse of the 3D network comprising the gel microstructure. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
39057445_p20 | 39057445 | sec[1]/sec[4]/p[0] | 2.5. Confocal Microscopy of Non-Sonicated and Sonicated Ultrez 10 Microgels | 4.222656 | biomedical | Study | [
0.9990234375,
0.0003216266632080078,
0.0005316734313964844
] | [
0.99951171875,
0.00012314319610595703,
0.00038933753967285156,
0.00005131959915161133
] | Confocal microscopy observations of the non-sonicated and sonicated Ultrez 10 microgels were performed to evidence changes in their microstructure due to sonication. Figure 10 a–e show the resulting characteristic microstructure of SM0, SM60, SM120, SM180 and SDM180 microgels, respectively. It can be observed that microgel microstructure becomes more open or less compact with increasing the sonication time, as well as for the SDM180 sample. The domains appear to increase in size with sonication time, leaving a less compact or more porous structure with more free solvent. Interestingly, the structure of the microgels with longer sonication time resembles that of less concentrated microgels (see, for example, ). Oelschlaeger et al. analyzed the microstructure of Ultrez 10 microgels and its relationship with macroelasticity. These authors found that the bulk shear modulus, | G* |, strongly depends on the fraction of compact regions formed by aggregated particles in which less free solvent is available . It is expected that decreasing such compact regions and more free solvent with increasing the sonication time results in enhanced lubrication among sponges and the concomitant decrease in viscoelastic characteristics of the microgel, these represented by the shear modulus, viscosity and yield stress, in agreement with results in Figure 1 , Figure 2 and Figure 3 . Also, the SLS measurements presented above corroborate the change in molecular weight of Ultrez 10 macromolecules due to sonication, which results in softer microgels. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
39057445_p21 | 39057445 | sec[2]/p[0] | 3. Conclusions | 4.160156 | biomedical | Study | [
0.9990234375,
0.00031113624572753906,
0.0005917549133300781
] | [
0.99951171875,
0.00013339519500732422,
0.00037217140197753906,
0.000049233436584472656
] | The effect of sonication on the molecular structure of polyacrylic acid (Carbopol ® Ultrez 10) and its rheological behavior in aqueous dispersions and microgels containing 0.25 wt.% of the polymer was analyzed in this work by rheometry, molecular weight measurements via static light scattering (SLS), Fourier transform infrared (FTIR) spectroscopy and confocal microscopy. For this, the precursor dispersion and the microgel were sonicated in a commercial ultrasound bath at a fixed power and at various times. The shear modulus, yield stress and viscosity of the microgel decreased systematically with an increase in the sonication time, reflecting a softening of the microgel microstructure. Meanwhile, the overall rheological behavior remained Herschel–Bulkley-like. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
39057445_p22 | 39057445 | sec[2]/p[1] | 3. Conclusions | 4.230469 | biomedical | Study | [
0.99951171875,
0.0003192424774169922,
0.0003695487976074219
] | [
0.99853515625,
0.0002301931381225586,
0.001064300537109375,
0.00006729364395141602
] | SLS measurements evidenced a reduction in the molecular weight of polyacrylic acid with sonication time; this reduced to almost one-third of its original value after 180 min. FTIR measurements show that sonication produces scission in the C-C links of the Carbopol ® backbone, which results in chains with the same chemistry but lower molecular weight. Confocal microscopy measurements revealed a diminution of the size of the microsponge domains with increasing sonication time, which is reflected in a softer microstructure resulting from the reduction in the molecular weight of polyacrylic acid. Finally, the results in this work indicate that both the microstructure and rheological behavior of microgels, in particular, and complex fluids, in general, may be manipulated or tailored by high-power ultrasonication. Special interest may be paid to naturally occurring or synthetic polymers whose high molecular weight results in high-viscosity solutions and gels that limit their applications. Future work considers additional characterization of the microgels after being submitted to variable ultrasound power, as well as its application to other gel-forming polymers of practical interest. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
39057445_p23 | 39057445 | sec[3]/p[0] | 4. Materials and Methods | 4.113281 | biomedical | Study | [
0.9990234375,
0.00020813941955566406,
0.0006346702575683594
] | [
0.99755859375,
0.00200653076171875,
0.0003218650817871094,
0.00006961822509765625
] | The polymer utilized in this work was a polyacrylic acid, Carbopol ® Ultrez 10 (Lubrizol Corporation, Wickliffe, OH, USA). Carbopol ® resins are hydrophilic cross-linked acrylic acid polymers differing in cross-link density. The more highly cross-linked members of the Carbopol ® family are rigid particles, while the more lightly cross-linked members are delivered as micron-sized powder particles, which can largely swell, being these last best representatives of microgels . When the resin is mixed with water, an acid dispersion is obtained. Upon neutralization with a suitable base, the protons in the carboxylate groups are substituted by the cation of the base, and the molecules adopt a highly expanded configuration. The as-formed, highly swollen and deformable particles resemble individual sponges that give rise to elastoviscoplastic microgels . | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057445_p24 | 39057445 | sec[3]/p[1] | 4. Materials and Methods | 4.253906 | biomedical | Study | [
0.9990234375,
0.0003638267517089844,
0.0005917549133300781
] | [
0.99951171875,
0.00023448467254638672,
0.0002732276916503906,
0.00005561113357543945
] | The structure and rheological behavior of Carbopol ® dispersions and microgels are dependent on their preparation conditions, including the type of mixing, mixing procedure and pH . Excessive shear during mixing affects the microstructure and rheological behavior of the as-formed microgels. Particularly, excessive shear of Carbopol ® Ultrez 10 microgels has been reported to produce thixotropy . Therefore, dispersions and microgels in this work were prepared, respectively, following a standard procedure to obtain non-thixotropic or simple yield-stress microgels . For this, Carbopol ® Ultrez 10 was dissolved at 0.25 wt.% in bi-distilled water under continuous stirring at 500 rpm for 1 h with a twisted three-blade turbine impeller. Since Carbopol ® microgels are sensitive to fungus and bacteria, we added 0.5 wt.% of phenoxyethanol as a preservative to the dispersion to ample the microgel’s useful lifetime from a few days up to two weeks. (It is noteworthy here that after this lapse, the microgels start to age even though they do not show evidence of fungus and/or bacteria for several months.) Then, the dispersion containing preservative was neutralized with a 5 mol/L NaOH aqueous solution to obtain a pH = 7.02 ± 0.02 while keeping the same stirring conditions until the gel was well formed and free of air bubbles (0.5 h). It is known that the rheological behavior of Carbopol microgels is very sensitive to pH, with a broad maximum or plateau at around pH 5–10, and there is a considerable decrease in the yield stress and viscosity out of this range . In this work, we used the neutral pH since it produces a jammed structure of swelled sponges that raises the characteristic gel behavior . Once prepared, the microgel sample was maintained at rest in a dark place at ambient temperature for one day. Afterward, beakers containing 70 mL of microgel were subjected to sonication for 0, 60, 120 and 180 min, respectively, in a water-containing ultrasonic cleaner (Cole-Parmer ® , Vernon Hills, IL, USA) of 1.5 L of capacity and 150 Watts of sonic power. Sonication started at room temperature (~26 °C), which increased up to 63 °C after 180 min due to the energy dissipated by the ultrasonic treatment. This temperature rise does not affect the molecular characteristics of Ultrez 10 aqueous dispersions and microgels since thermal depolymerization of polyacrylic acid aqueous solutions occurs at above 180 °C and high pH conditions (~10) . The samples with different sonication times are labeled as sonicated microgels: SM0, SM60, SM120 and SM180, respectively. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057445_p25 | 39057445 | sec[3]/p[2] | 4. Materials and Methods | 3.921875 | biomedical | Study | [
0.99755859375,
0.00019752979278564453,
0.0020542144775390625
] | [
0.9970703125,
0.0029315948486328125,
0.00018215179443359375,
0.000057637691497802734
] | For comparison, another microgel was prepared from a previously sonicated dispersion. In this case, a dispersion containing the same concentration of Ultrez 10 (0.25 wt.%) was prepared as stated above and left to rest for one day. Next, the dispersion was divided into two parts, and one of these submitted to 180 min of sonication. Then, the sonicated dispersion was neutralized to obtain another microgel sample labeled as sonicated dispersion microgel: SDM180. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057445_p26 | 39057445 | sec[3]/sec[0]/p[0] | 4.1. Rheological Characterization | 4.152344 | biomedical | Study | [
0.99951171875,
0.0002868175506591797,
0.00040268898010253906
] | [
0.99951171875,
0.000148773193359375,
0.0004017353057861328,
0.000049233436584472656
] | The rheological behavior of the microgels was assessed via small-amplitude oscillatory shear (SAOS) and steady shear measurements using an AR G2 stress-controlled rheometer (TA Instruments, New Castle, DE, USA) and the parallel-plate geometry. Since this type of microgel is very prone to slip at the shearing surfaces, the plates were covered with sandpaper # 150 to suppress slip . As for the neat dispersions (with and without sonication), their flow behavior was analyzed by using a double-gap Couette cell attached to the AR G2 rheometer. All the flow experiments were performed at 25 °C; for this, the rheometer was equipped with Peltier systems for temperature control of both the parallel-plate geometry and double-gap cell. Finally, despite the fact that this microgel preparation procedure resulted in reproducible rheological behavior for up to two weeks , all steady and dynamic flow experiments were carried out using fresh samples and preceded by a conditioning pre-shear of the microgel at 100 s −1 for 60 s, followed by one minute at rest to eliminate any possible aging affect and to start the rheological experiments with similar gel microstructure . | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057445_p27 | 39057445 | sec[3]/sec[1]/p[0] | 4.2. Determination of Weight-Average Molecular Weight (M w ) of Ultrez 10 | 4.191406 | biomedical | Study | [
0.9990234375,
0.000270843505859375,
0.0006422996520996094
] | [
0.99951171875,
0.00022161006927490234,
0.00022161006927490234,
0.000042438507080078125
] | To assess possible changes in the molecular characteristics of Carbopol ® Ultrez 10 due to sonication, its M w and the second virial coefficient ( A 2 ) before and after sonication were determined at a temperature of 25 °C by static light scattering (SLS, Litesizer™ 500, Anton Paar GmBH, Graz, Austria). The SLS technique was chosen as it allows the measurement of absolute M w and has been successfully used to measure the M w of other polyelectrolyte molecules . M w and A 2 are obtained from the following: (1) K c R θ = 1 M w + 2 A 2 c where K is the optical constant, c is the concentration of Carbopol ® Ultrez 10 in the solution, and R θ is the Rayleigh ratio. The K and R θ were calculated as follows : (2) K = 2 π 2 λ 4 N A n 0 d n d c 2 (3) R θ = ( I s − I 0 ) n 0 2 I T n T 2 R T | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
39057445_p28 | 39057445 | sec[3]/sec[1]/p[1] | 4.2. Determination of Weight-Average Molecular Weight (M w ) of Ultrez 10 | 4.15625 | biomedical | Study | [
0.9951171875,
0.0002799034118652344,
0.00466156005859375
] | [
0.98388671875,
0.0153656005859375,
0.0005679130554199219,
0.00010263919830322266
] | In Equation (2), λ = 658 nm is the wavelength of the incident light, N A is Avogadro’s number, n 0 = 1.332485 is the refractive index of solvent (bidistilled water), and d n /d c is the rate of change in the refractive index as a function of concentration. In Equation (3), I S and I 0 are the scattered light intensities of solutions and solvent, respectively; I T is the dispersed light intensity of a standard (toluene in this case); n T = 1.48983 is the refractive index of toluene; and R T = 1.14574 × 10 −5 cm −1 is the Rayleigh’s ratio of toluene. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057445_p29 | 39057445 | sec[3]/sec[1]/p[2] | 4.2. Determination of Weight-Average Molecular Weight (M w ) of Ultrez 10 | 4.152344 | biomedical | Study | [
0.99951171875,
0.00027298927307128906,
0.00040912628173828125
] | [
0.99951171875,
0.00015354156494140625,
0.00022208690643310547,
0.000046253204345703125
] | To measure the molecular weight of the Ultrez 10 before and after sonication, six aqueous dissolutions were prepared from the sonicated (SD180) and non-sonicated (SD180) dispersions, both with an initial concentration of 2.5 mg/mL. The dissolutions were prepared at 10, 20, 30, 40, 60 and 80%, for which the refractive index as a function of Ultrez 10 concentration was first determined using a refractometer (Abbemat 550, Anton Paar, Graz, Austria). For the refractive index determination, 0.3 mL of each sample measured with a micropipette was placed in the refractometer. The refractive index of the bidistilled water used to prepare the microgels and dissolution was then found to be n = 1.332485 (see Table 2 ). These data were used to compute the Kc / R θ values and afterward to determine the molecular weight using the SLS technique. For this, 1.2 mL of each dissolution was added into a clean cuvette of quartz, which was, in turn, inserted in the Litesizer to start measurements. All experiments were carried out at 25 °C. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999999 |
39057445_p30 | 39057445 | sec[3]/sec[2]/p[0] | 4.3. Confocal Microscopy | 4.125 | biomedical | Study | [
0.99951171875,
0.00021064281463623047,
0.00038743019104003906
] | [
0.99951171875,
0.0002930164337158203,
0.00024771690368652344,
0.00004315376281738281
] | The changes in microgel microstructure, along with sonication time, were assessed by confocal microscopy using an LSM 800 (Zeiss Group, Oberkochen, Germany) microscope with a green light excitation λ = 532 nm and the Efficient Navigation Software (version 2.6 Blue edition, Zeiss group, Oberkochen, Germany). For this, a few drops of a 1.1 × 10 −4 M Rhodamine 6G (Sigma-Aldrich, St. Louis, MO, USA) aqueous solution were added to the samples and gently mixed to obtain uniform red-colored microgels. Then, the microgel samples were placed on glass slides for observation. The micrographs were acquired with apochromatic objectives of 20× and 40× with numerical apertures of 0.8 and 1.3, respectively. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
39057445_p31 | 39057445 | sec[3]/sec[3]/p[0] | 4.4. Fourier Transform Infrared Spectroscopy | 4.152344 | biomedical | Study | [
0.99951171875,
0.00024247169494628906,
0.0003256797790527344
] | [
0.99951171875,
0.0002868175506591797,
0.00023448467254638672,
0.00005054473876953125
] | The identification of the functional groups of the non-sonicated and sonicated lyophilized Ultrez 10 samples was carried out by Fourier transform infrared spectroscopy (FTIR) using a IRAffinity spectrometer (Shimadzu, Kyoto, Japan) with an Attenuated Total Reflection (ATR) accessory in the absorbance mode, and in the wavenumber range from 600 to 3800 cm −1 , with 4 cm −1 resolution, 16 scans. To obtain the FTIR spectrum of the Carbopol ® Ultrez 10 before and after sonication, the dispersions SD0 and SD180 were dried by lyophilization. For this, 100 mL of the dispersion was placed in a lyophilization vessel, frozen at −10 °C, and then introduced into a lyophilizer (FreeZone 6, LABCONCO, Kansas City, MO, USA). Freeze drying was carried out for eight hours/day for three days at a vacuum pressure of 7 × 10 −3 mBar and a temperature of −25 °C. At the end of each day, the vessel was placed in a freezer to continue the process the next day. Then, 1 mg of the lyophilized Ultrez 10 powders was placed and gently pressed against a high-refractive-index diamond prism located in the ATR accessory to measure the infrared spectrum. | [
"José Pérez-González",
"Yusef Muñoz-Castro",
"Francisco Rodríguez-González",
"Benjamín M. Marín-Santibáñez",
"Esteban F. Medina-Bañuelos"
] | https://doi.org/10.3390/gels10070420 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
PMC11276206_p0 | PMC11276206 | sec[0]/p[0] | 1. Introduction | 1.164063 | other | Other | [
0.006923675537109375,
0.0005078315734863281,
0.99267578125
] | [
0.00531005859375,
0.9931640625,
0.0010061264038085938,
0.0004563331604003906
] | Food prices in developing countries show a cyclical pattern of seasonal fluctuations . In a typical normal year, food prices are lowest during the harvest season and then gradually rise and peak in the lean season before the next harvest. With new foods coming to the market, prices decline and enter the next volatility cycle . The price fluctuation pattern is mainly related to the food production cycle and the seasonality of supply, which objectively creates conditions for farmers’ intertemporal food sales for arbitrage. | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
PMC11276206_p1 | PMC11276206 | sec[0]/p[1] | 1. Introduction | 1.078125 | other | Other | [
0.00209808349609375,
0.0005431175231933594,
0.99755859375
] | [
0.003997802734375,
0.994140625,
0.001068115234375,
0.00074005126953125
] | Even so, most Chinese farmers show a negative attitude towards food sales. They sell their hard-earned food in the shortest time and most convenient way at low prices. It does not look like they care about the benefit opportunities. In 2020, China comprehensively won the battle against poverty, and 98.99 million rural poor were lifted out of poverty by the current standard . Nevertheless, many small farmers are still living just above the poverty line, and food sales have the most direct impact on their production returns. Conversely, the negativity of Chinese farmers towards food sales has been observed in both academia and reality . | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999995 |
PMC11276206_p2 | PMC11276206 | sec[0]/p[2] | 1. Introduction | 1.104492 | other | Other | [
0.00445556640625,
0.00038433074951171875,
0.9951171875
] | [
0.0276641845703125,
0.96923828125,
0.0020427703857421875,
0.0008668899536132812
] | Explanations for farmers’ negativity in food sales focus on liquidity, storage, and transaction cost constraints . Storing food for opportunistic sale is only feasible if there are adequate funding sources, enough storage space and facilities, and relatively low transaction costs. Other factors that may have impacts include planting size , storage losses , and risk preference . However, food sales behavior cannot be simply explained by a single factor or perspective from economic interests, it is a comprehensive psychological choice under external uncertainty and is closely related to farmers’ risk perception and risk preference . | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
PMC11276206_p3 | PMC11276206 | sec[0]/p[3] | 1. Introduction | 1.098633 | other | Other | [
0.004611968994140625,
0.00031113624572753906,
0.9951171875
] | [
0.297607421875,
0.69775390625,
0.0024929046630859375,
0.001972198486328125
] | We contribute a new insight that farmers’ negativity in the timing of food sales is based on the risk perception of intertemporal sales under utility comparison. On the one hand, Chinese farmers’ cultivated land is fragmented on a small scale, and the income from food sales accounts for a low proportion of the total household income , so farmers perceive that the utility brought by intertemporal food sales is insufficient; on the other hand, most of the farmers are averse to risk , and based on the fact that food prices in the previous years did not always rise over time or rose at a small rate, the aversion to negative return may induce farmers to sell food negatively. Further, consider the amplification of risk perception by constraints, such as liquidity, storage, and transaction costs, which leads farmers to perceive the utility of the risk returns from intertemporal sales to be lower than the utility of the certainty returns from current sales. The negative food sale is in fact a rational, constrained “second-best” choice for farmers. | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999995 |
PMC11276206_p4 | PMC11276206 | sec[0]/p[4] | 1. Introduction | 2.888672 | other | Review | [
0.05389404296875,
0.0012884140014648438,
0.94482421875
] | [
0.1619873046875,
0.04803466796875,
0.78857421875,
0.0012454986572265625
] | Regarding the economic behavior of farm households, it has been widely recognized in the existing literature that risk perception and risk preference are central variables in individual risk behavior decisions . Using mathematical models, Pratt pioneered the idea that an individual’s risk behavior depends on risk perception and risk preference. Kahneman and Tversky proposed in prospect theory that risk perception and risk preference are the two main factors influencing an individual’s decision making and that they are inseparably linked. Risk perception is the decision maker’s judgment and evaluation of the magnitude of risk. Slovic defined risk perception as the process by which people rely on their intuition to make risk judgments and assessments of the unknown, whereas risk preference is the psychological response of the decision maker to risk. Although the importance of risk perception and risk preference in individual risk decision making is unanimously recognized, there is still a debate on the relationship between the two and the influence of their behavioral effects . Sitkin and Weingart argued that risk preference affects the relative salience of situational threats or opportunities, leading to biased risk perception. Lusk and Coble considered that risk perception is more influential than risk preference in the acceptance of GM foods. | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999995 |
PMC11276206_p5 | PMC11276206 | sec[0]/p[5] | 1. Introduction | 3.060547 | other | Study | [
0.11944580078125,
0.0007958412170410156,
0.8798828125
] | [
0.986328125,
0.006786346435546875,
0.0068206787109375,
0.0002918243408203125
] | We reveal the separate roles and the mechanism between risk perception and risk preference in influencing farmers’ food sale decisions. Previous studies, including prospect theory, tend to discuss the two together in a mishmash without directly examining the causal mechanisms of the behavioral effects, and a decoupled description of the two is needed if we are to accurately analyze the effects of risk perception and risk preference on farmers’ food sale behavior. Specifically, in the context of food sales by farmers, risk perception and risk preference are the main dimensions for farmers to consider the risk of food storage and sales, but for farmers who are mostly risk averse, risk perception plays a more important role in the actual food sales process. This is consistent with the findings of Kahneman and Lovallo , Weber et al. , and Lusk and Coble . With the application of new technologies, farmers first systematically use the information they have gathered to assess the magnitude of the risk of food sales, rather than considering directly based on risk preference. For example, Barrett and Dorosh stated that the risk perception of price uncertainty reduces the incentives for poor farmers to store food in Madagascar. Through a randomized controlled experiment, Burke et al. showed that credit constraints amplified the risk perception of Kenyan farmers, leading to “sell low and buy high” for food. | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
PMC11276206_p6 | PMC11276206 | sec[0]/p[6] | 1. Introduction | 1.055664 | other | Other | [
0.016143798828125,
0.00092315673828125,
0.98291015625
] | [
0.0201263427734375,
0.9677734375,
0.01047515869140625,
0.00157928466796875
] | The remainder of the article is organized as follows. The second part constructs the theoretical framework and conducts the mechanism analysis; the third part presents the data sources and the choice of an econometric model; the fourth part reports and analyzes the estimation results; and the last part concludes the full article. | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
PMC11276206_p7 | PMC11276206 | sec[1]/sec[0]/p[0] | 2.1. Theoretical Framework of Risk Perception and Farmers’ Timing of Food Sales | 2.964844 | other | Study | [
0.07989501953125,
0.0006051063537597656,
0.91943359375
] | [
0.98681640625,
0.01012420654296875,
0.0027790069580078125,
0.0003495216369628906
] | Based on the expected utility theory, this paper draws on Cardell and Michelson’s analysis to develop a theoretical model of the relationship between risk perception and farmers’ timing choices for food sales. As the basis of individual decision-making theory under uncertain conditions, although some of the shortcomings have been challenged by the “Allais Paradox” and prospect theory, the expected utility theory (EUT) can still provide a more complete explanation under assumptions of rationality, risk aversion, and long-term decisions , while food farmers fulfill the assumptions. First, farmers tend to be rational. Farmers systematically use the information they have collected to assess and consider the impact of implementing the behavior before making decisions to sell food, and although farmers’ decisions show irrationality, they are essentially rational choices under the constraints of external conditions. Secondly, farm households are basically risk averse . Farmers’ risk preference is risk averse and is considered to be a consistent and unchanging psychological trait . When faced with the complexity and variety of agricultural risks, farmers tend to show more risk-averse attitudes and shy away from agricultural production activities with higher expected returns . Risk minimization tends to be a more important decision-making objective for most farmers than profit maximization. Again, farmers tend to be consistent in their long-term decision making. Most farmers have much experience in agricultural activities, and their responses to losses and profits from food sales are relatively rational, and long-term practice tends to stabilize farmers’ mindsets. | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
PMC11276206_p8 | PMC11276206 | sec[1]/sec[0]/p[1] | 2.1. Theoretical Framework of Risk Perception and Farmers’ Timing of Food Sales | 2.121094 | other | Study | [
0.03497314453125,
0.0003573894500732422,
0.96484375
] | [
0.7646484375,
0.2330322265625,
0.0017023086547851562,
0.0006642341613769531
] | First, based on the above analysis, we assume that farmers are rational, risk averse, and price takers in input and output markets and that they are in a perfectly competitive market with identical storage, credit conditions, and zero cost. At harvest time, the price p h is known, but the price of lean season p l is unknown. Storage returns r = p l − p h p h ; if r > 0, then it should be stored, but the randomness of lean season prices exposes farmers to price risk and, realistically, farmers face additional costs, such as credit and storage. We assume that farmers have Von Neumann–Morgenstern (VNM) utility function to calculate the deterministic equivalent rate of return for the farmer. The risk premium equation is as follows: (1) E U w 1 + r = U w 1 + C where w represents the farmer’s wealth, r represents the risk–return ratio of intertemporal sales, and C is the certainty equivalent rate of the return that the farmer is willing to forgo regarding intertemporal sales. Assuming that the utility function U ( w 1 + r ) is a second-order continuous derivable, a second-order Taylor expansion on the left side of the equal sign in Equation (1) at the mean w 1 + r ¯ yields the following: (2) U w 1 + r ≈ U w 1 + r ¯ + U ′ w r − r ¯ + 1 2 U ″ w r − r ¯ 2 | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
PMC11276206_p9 | PMC11276206 | sec[1]/sec[0]/p[2] | 2.1. Theoretical Framework of Risk Perception and Farmers’ Timing of Food Sales | 2.425781 | biomedical | Other | [
0.5732421875,
0.0009975433349609375,
0.425537109375
] | [
0.341064453125,
0.6572265625,
0.0012035369873046875,
0.0006670951843261719
] | In Equation (2), U ′ = ∂ U ∂ w , U ″ = ∂ U 2 ∂ w 2 . Taking the expectation in Equation (2) yields the following: (3) E U w 1 + r ≈ U w 1 + r ¯ + U ′ w ∗ E r − r ¯ + 1 2 U ″ w 2 σ 2 | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
PMC11276206_p10 | PMC11276206 | sec[1]/sec[0]/p[3] | 2.1. Theoretical Framework of Risk Perception and Farmers’ Timing of Food Sales | 1.265625 | other | Other | [
0.00949859619140625,
0.00036835670471191406,
0.990234375
] | [
0.078369140625,
0.919921875,
0.0010356903076171875,
0.0009140968322753906
] | In Equation (3), σ 2 is the risk–return variance of a farmer’s choice for intertemporal sales, representing farmers’ risk perception of intemporal sales. The greater the farmer’s perceived risk of intertemporal sales, the greater σ 2 . Since E r − r ¯ = 0 , Equation (3) reduces to the following: (4) E U w 1 + r ≈ U w 1 + r ¯ + 1 2 U ″ w 2 σ 2 | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
PMC11276206_p11 | PMC11276206 | sec[1]/sec[0]/p[4] | 2.1. Theoretical Framework of Risk Perception and Farmers’ Timing of Food Sales | 2.177734 | other | Other | [
0.42236328125,
0.0011463165283203125,
0.57666015625
] | [
0.35546875,
0.64208984375,
0.0013780593872070312,
0.0008692741394042969
] | Also, a first-order Taylor expansion on the right side of the equality sign in Equation (5) at w 1 + r ¯ yields the following: (5) U w 1 + r ≈ U w 1 + r ¯ + U ′ w C − r ¯ | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
PMC11276206_p12 | PMC11276206 | sec[1]/sec[0]/p[5] | 2.1. Theoretical Framework of Risk Perception and Farmers’ Timing of Food Sales | 2.365234 | biomedical | Other | [
0.611328125,
0.001117706298828125,
0.387451171875
] | [
0.408203125,
0.58935546875,
0.0015859603881835938,
0.0008020401000976562
] | Joining Equations (4) and (5), we obtain the following: (6) C ≈ r ¯ − − 1 2 w U ′ ′ U ′ σ 2 | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
PMC11276206_p13 | PMC11276206 | sec[1]/sec[0]/p[6] | 2.1. Theoretical Framework of Risk Perception and Farmers’ Timing of Food Sales | 1.738281 | other | Study | [
0.026458740234375,
0.0003116130828857422,
0.97314453125
] | [
0.5341796875,
0.463134765625,
0.0016908645629882812,
0.000823974609375
] | We set the absolute risk aversion coefficient as A = − U ″ U ′ , which denotes the amount of wealth a farmer is willing to give up in order to hedge the risk of losing 1 unit quantity of wealth; the relative risk aversion coefficient, R = − w U ″ U ′ , denotes the proportion of wealth that a farmer is willing to give up in order to avoid the risk of a 1 percent loss of wealth. Logically, A varies greatly with the amount of individual wealth and does not completely portray the risk preference of farmers; the degree of aversion to the risk of proportional loss of wealth, R , is more reflective of the inherent attitude of farmers to risk, and this paper uses R to refer to the risk preference of farmers. A higher R value means that farmers are more risk averse and have a lower risk preference. Therefore, the certainty equivalent return C can be expressed as follows: (7) C ≈ r ¯ − 1 2 R σ 2 | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999998 |
PMC11276206_p14 | PMC11276206 | sec[1]/sec[0]/p[7] | 2.1. Theoretical Framework of Risk Perception and Farmers’ Timing of Food Sales | 1.18457 | other | Other | [
0.012603759765625,
0.0004048347473144531,
0.98681640625
] | [
0.223388671875,
0.77294921875,
0.0021343231201171875,
0.001438140869140625
] | From the theoretical mechanism, an increase in R and σ 2 in Equation (7) implies a decrease in C , i.e., the value of intertemporal food sales diminishes as the farmer’s risk preference decreases and risk perception increases, thus reducing the likelihood that the farmer will choose intertemporal food sales. This leads to the following two research hypotheses: | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
PMC11276206_p15 | PMC11276206 | sec[1]/sec[0]/p[8] | 2.1. Theoretical Framework of Risk Perception and Farmers’ Timing of Food Sales | 2.255859 | other | Study | [
0.053863525390625,
0.000431060791015625,
0.94580078125
] | [
0.8896484375,
0.1053466796875,
0.00406646728515625,
0.000698089599609375
] | In the framework of expected utility theory and its variants, risk preference is only a descriptive label that technically refers to the curvature of the utility function. When farmers are mostly risk averse, which is considered to be a consistent and invariant psychological trait, then U w ′ > 0 , U w ″ < 0 , R can be approximated as a positive constant; the deterministic rate of return C is actually more susceptible to risk perception σ 2 . Risk aversion is explained at the core of psychology as “risk taking demands a premium return” , while the intertemporal food sales by farmers are based on the pursuit of premium returns. Compared with the relatively fixed risk-averse attitude in food sales, farmers’ perception of the magnitude of risk in intertemporal sales is more helpful in balancing return and risk, which is also in line with the microeconomic assumption of rational individual risk behavior at the same time. As pointed out by Weber et al. , individual risk behavior is mainly related to differences in risk perception rather than risk preference. This leads to the following research hypothesis, H 3 : | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999995 |
PMC11276206_p16 | PMC11276206 | sec[1]/sec[1]/p[0] | 2.2. Analysis of the Moderating Mechanism of Risk Preference | 1.098633 | other | Other | [
0.00862884521484375,
0.0003650188446044922,
0.9912109375
] | [
0.11395263671875,
0.88232421875,
0.002613067626953125,
0.0012407302856445312
] | Farmers’ risk decision-making behavior is not only directly affected by risk perception but also by the interaction effect between risk perception and risk preference. The impact of risk perception on farmers’ timing of food sales varies according to risk preference, and combining the analysis of the theoretical framework and farmers’ risk characteristics, the moderating mechanisms of risk preference are mainly based on two paths: theoretical and practical. | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999996 |
PMC11276206_p17 | PMC11276206 | sec[1]/sec[1]/p[1] | 2.2. Analysis of the Moderating Mechanism of Risk Preference | 3.474609 | other | Study | [
0.19677734375,
0.0007448196411132812,
0.80224609375
] | [
0.97802734375,
0.015960693359375,
0.005947113037109375,
0.00027251243591308594
] | First, the theoretical path. From the theoretical mechanisms of related studies, risk preference and risk perception are generally negatively correlated. Vlek and Stallen point out that the higher a person’s risk preference is, the more likely he or she is to underestimate the risk of certain situations, which in turn reduces risk perception. Sitkin and Weingart conclude through behavioral experiments that individuals with a higher risk preference, whose risk perception tends to be lower, and people with a low risk preference may be very sensitive to risk. Specifically, with regard to the timing of food sales, farmers with lower risk preferences will pay extra attention to the risk factors in intertemporal food sales and thus have higher risk perceptions, while farmers with high risk preferences are more likely to recognize and assess positive factors and thus overestimate the probability of obtaining returns from their food sales, and this overestimation of returns directly affects their risk perception of food sales. Meanwhile, based on the analysis of certainty equivalence in the theoretical framework, the juxtaposition of risk preference and risk perception in Equation (7) negatively affects farmers’ choice of intertemporal food sales, and the increase in either risk aversion or the risk perception level will make farmers tend to give up intertemporal food sales, whereas the certainty equivalence of farmers’ expectations is relatively constant when other conditions are unchanged, and there may be a substitution effect between risk preference and risk perception. As R rises, the lower the risk preference, the smaller the decrease in the likelihood of farmers abandoning intertemporal food sales as risk perception increases, i.e., risk preference has a moderating effect on risk perception affecting farmers’ intertemporal food sales. | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
PMC11276206_p18 | PMC11276206 | sec[1]/sec[1]/p[2] | 2.2. Analysis of the Moderating Mechanism of Risk Preference | 1.067383 | other | Other | [
0.003696441650390625,
0.0003867149353027344,
0.99609375
] | [
0.0307159423828125,
0.966796875,
0.0013132095336914062,
0.0009684562683105469
] | Second, the practical path. Small farmers in China who rely on food farming are still at the poverty line. Most of them do not have the strength to take risks and are indeed risk averse and have a low risk preference. Farmers with a low risk preference and a high risk perception react more sensitively to possible losses during food sales and are less concerned with less rewarding but relatively secure options. It follows that intertemporal food sales with higher food sales risk may vary significantly with farmers’ risk preference, whereas the difference may not be significant for two-phase food sales with lower food sales risk. | [
"Tan Tian",
"Xia Zhao"
] | https://doi.org/10.3390/foods13142243 | N/A | https://creativecommons.org/licenses/by/4.0/ | en | 0.999997 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.