Explore the occurrence and nature of questionable research practices (QRPs) in the reporting of messages and conclusions in international scientific Health Services Research (HSR) publications authored by researchers from HSR institutions in the Netherlands.In a joint effort to assure the overall quality of HSR publications in the Netherlands, 13 HSR institutions in the Netherlands participated in this study. Together with these institutions, we constructed and validated an assessment instrument covering 35 possible QRPs in the reporting of messages and conclusions. Two reviewers independently assessed a random sample of 116 HSR articles authored by researchers from these institutions published in international peer-reviewed scientific journals in 2016.Netherlands, 2016.116 international peer-reviewed HSR publications.Median number of QRPs per publication, the percentage of publications with observed QRP frequencies, occurrence of specific QRPs and difference in total number of QRPs by methodological approach, type of research and study design.We identified a median of six QRPs per publication out of 35 possible QRPs. QRPs occurred most frequently in the reporting of implications for practice, recommendations for practice, contradictory evidence, study limitations and conclusions based on the results and in the context of the literature. We identified no differences in total number of QRPs in papers based on different methodological approach, type of research or study design.Given the applied nature of HSR, both the severity of the identified QRPs, and the recommendations for policy and practice in HSR publications warrant discussion. We recommend that the HSR field further define and establish its own scientific norms in publication practices to improve scientific reporting and strengthen the impact of HSR. The results of our study can serve as an empirical basis for continuous critical reflection on the reporting of messages and conclusions. Given the explorative nature of this study, we applied a broad and sensitive definition of ‘questionable research practices’ (QRPs) that allows for the identification of QRPs previously overlooked in related assessments.This study describes an assessment of publications and is therefore able to detect QRPs that go unnoticed in survey studies that rely on self-report.Although we aimed to develop a reliable measurement instrument that would guide the review process, the instrument allowed latitude for the reviewer’s interpretation.In our assessment method, we relied on consensus among assessors, which inevitably introduces some subjectivity.Because publications were selected based on the title, selection bias might have occurred.The Lancet’s series ‘Increasing value: reducing waste’. This series has stirred the international scientific community, prompting funders, regulators, academic institutions and scientific publishers to act. Funders of biomedical research have responded by organising conferences on research waste, and journal editors have initiated discussions on data sharing and open access.In 2009, Chalmers and Glasziou estimated that 85% of research funding in biomedical sciences was wasted avoidably,et al shows that estimates for the occurrence of questionable research practices in the interpretation of results in scientific publications vary from 10% of publications deriving discordant conclusions from study results to 100% of publications containing rhetorical practices resulting in spin, such as failure to compare risk with benefits in randomised controlled trials (RCTs).The HSR field is an applied field of research, and produces evidence on topics such as copayments, evaluation of quality improvement efforts, cost-effectiveness of medications, patient empowerment, therapy compliance and effects of policies. Given the growing evidence for the prevalence of QRPs in the reporting of messages and conclusions in the biomedical field,Just like biomedical researchers, health services researchers are under pressure to publish in high-impact journals to increase their citation scores and attract media attention to augment their prestige and chances for future research funding and job security.Although reporting in scientific publications is highly standardised, the discussion and conclusion sections offer researchers relative freedom when deriving messages and conclusions from study results.This study assessed scientific publications authored by researchers from 13 HSR groups, departments or institutions (hereafter referred to as ‘HSR institutions’) in the Netherlands, including both academic and non-academic institutions. These institutions all agreed to participate in an effort to assure the overall quality of HSR publications in the Netherlands.We conducted a literature review on QRPs in the reporting of messages and conclusions in biomedical research and HSR.We developed an extensive list of QRPs in the reporting of messages and conclusions. Items were based on the EQUATOR checklistsWe developed a data extraction form in Excel that contained the list of QRPs and bibliometric information, and conducted a pilot to evaluate its feasibility and usability. In the pilot, two assessors  independently assessed five international HSR publications to identify modifications needed to improve the form, and to align the interpretation of the items. The project group discussed the proposed modifications, resulting in the final version. The data extraction form  or obtained from secretaries or librarians. All lists were verified by the respective HSR institutions. These lists included both HSR and non-HSR publications.Two researchers  selected all titles from the 13 publication lists that were likely to indicate empirical or systematic assessment studies in HSR. Publications were included if their title fitted the definitions of HSR by Juttmann and Lohr and Steinwachs.The HSR publications (n=717) were assigned a random number. Per institution, the publications with unique first authors with the lowest assigned number were included in the sample. Three HSR institutions did not have enough publications with unique first authors, resulting in a selection of nine, eight and two publications for these institutions. Furthermore, two publications were excluded during assessment because they concerned research protocols. These publications were replaced by another publication authored by the same institution. One publication was excluded because its methodology was considered incomprehensible by the reviewers. Ultimately, 116 HSR publications were included (16% of tot sample).Two reviewers independently assessed all publications (RGG and TJ or RGG and JM). RGG has primarily qualitative HSR experience and is trained in health economics. TJ and JM have primarily quantitative HSR experience and are trained in public health, management, economics and law and medicine, respectively.The assessment started with a test phase. During this phase, agreements and disagreements in assessments of the first 30 publications were thoroughly discussed  to increase the accuracy of the assessments; agreement between the two reviewers  was 81% for the first 20 publications, which increased to 82% when assessing the next 10 publications. The notion emerged that it was necessary having two reviewers with complementary expertise assess each publication independently, followed by a consensus procedure and random check by the project leaders. RGG trained the third reviewer (JM).RGG assessed all included publications, while TJ assessed the first 59 publications, and JM the remaining 57. All data were entered in the data extraction form. QRPs were coded as either 1, ‘present’; 0, ‘not present’; −8, ‘not applicable to this study’ ; or −9, ‘not assessable’. To justify their assessments, the reviewers recorded their motivation for every identified QRP. At a later stage, QRPs in implications and recommendations for policy and practice were further refined into ‘not mentioned’ if no implication or recommendation was included in the publications, and ‘not sufficiently justified’, if the authors did not provide any explanation for their implications or recommendations. The reviewers held regular consensus meetings (after review of 10 publications) to discuss and reach agreement on all identified QRPs.During the consensus meetings, the reviewers compared their assessment of all items. Inconsistencies between the individually assessed QRPs were identified, discussed and adapted. Any remaining disagreements (n=2) were resolved by a senior researcher (DSK). NSK and DSK each reassessed a random sample of six publications, so 10% of all included publications (n=12). As a result, two identified QRPs were retracted, and two QRPs were added to the reassessed publications.The characteristics of the included publications were described by calculating their occurrence with the percentage or mean number of publications.We counted the total number of QRPs per publication, and the percentage of HSR publications with number of observed QRPs. The latter was visualised in a histogram. Occurrence of specific QRPs was calculated as a percentage of publications containing this particular QRP. The percentage of publications containing QRPs that were not applicable to qualitative research was calculated only for quantitative and mixed methods-based publications (n=83), .We used a Kruskal-Wallis test to calculate the difference in total number of QRPs applicable to all research designs by methodological approach  type of research  and study design  experimental, systematic review, economic evaluation, case study and meta-analyses). We used the Strengthening the Reporting of Observational Studies in Epidemiology checklist for observational studies in the reporting of this research.No patients were involved in this study. This study was designed with the input provided by the participating HSR institutions at a consensus meeting at the onset of the study, and individual interviews with the directors/leaders of the 13 participating institutions. During a progress meeting with the participating institutions, preliminary (aggregated level) results were discussed to validate and complement the interpretation of findings.A waiver for ethical approval was obtained for this study. To avoid negative consequences for the authors of the included publications, each publication was assigned a unique identification number. Extracted data were entered in SPSS using this number to separate author information from the study data.Of the 116 HSR publications, the median number of QRPs per publication was six , out of 35 possible QRPs. The distribution of the observed frequency of QRPs across publications is visualised in For each of the QRPs, we counted how often they were identified in the included publications. Online 10.1136/bmjopen-2018-027903.supp3Supplementary file 3*In 50.0% of publications, no implications for policy and practice were mentioned, and in 19.0% of publications, implications were mentioned without adequate justification.Implications for policy and practice do not adequately reflect the results in the context of the referenced literature (69.0%)*;**In 34.5% of publications, no recommendations for policy and practice were reported, and in 31.0% of publications, recommendations were mentioned without adequate justification.Recommendations for policy and practice do not adequately reflect the results in the context of the referenced literature (65.5%)**;Contradicting evidence is poorly documented (63.8%);Conclusions do not adequately reflect the findings as presented in the results section (46.6%);Possible impact of the limitations on the results is not or poorly discussed (44.0%);Conclusions are not supported by the results as presented in the context of the referenced literature (43.1%).QRPs that occurred most frequently were:The main source of evidence for supporting the results is based on the same underlying data (2.6%);Generalising findings to populations not included in the original sample is not justified (2.6%);Causative wording is used in the hypothesis/research question, although there is no theory to support causation (2.4%);Possible clinical relevance of statistically non-significant results is not addressed (2.4%);Generalising findings to time periods not included in the original study is not justified (0.0%).QRPs that occurred least frequently were:We explored the occurrence and nature of QRPs in the reporting of messages and conclusions in international scientific HSR publications authored by researchers from HSR institutions in the Netherlands, and examined the relationship between study type, methodology and design and the occurrence of QRPs. Our results indicate that HSR publications have a median of six QRPs per publication. We identified most QRPs in the reporting of implications for policy and practice, recommendations for policy and practice, contradictory evidence, study limitations and conclusions based on the results and in the context of the literature. No significant associations between number of QRPs and type of study, study design or methodological approach were identified.We applied a broad and sensitive definition of ‘questionable’, for instance by considering the absence of contradictory evidence or the absence of implications and recommendations for policy and practice as a QRP. The choice to not present contradictory evidence does not defy current publication checklists, yet this practice may hinder interpretation of findings in the full context of evidence. If authors searched for contradictory evidence, but did not mention its absence, readers of the publication would not have any clues on its existence.Knowledge on the occurrence of QRPs is often derived from survey studies, relying on self-report.Although we endeavoured to develop a reliable measurement instrument that would guide the review process, the instrument allowed latitude for the reviewer’s interpretation. Consequently, a different group of reviewers might arrive at somewhat different scoring frequencies for observed QRPs. However, because we defined each QRP in detail, it is unlikely that there would be substantial differences in the overall distribution of different types of QRPs across publications. Our consensus method contains a degree of subjectivity, and there is the risk that one reviewer’s opinion will dominate. To counteract this, NSK and DSK performed random checks on 10% of all assessments. By recording the motivation for every identified QRP, we supported the consistency of our measurement and justified our results. Because publications were selected based on the title, selection bias might have occurred. Considering we found no relationship between study characteristics and number of QRPs, it is unlikely that a different sample would have led to different results. Inevitably, reviewers sometimes assessed publications written by authors they knew professionally or personally, and as such, a positive view of a colleague’s work might have led to underestimating the QRPs in these publications.Our study results may be representative for HSR research publications internationally. Given the fact that publication in international journals is highly standardised in terms of language (English) and format, our findings can most likely be transferred to HSR communities in other countries.In HSR publications, recommendations for policy and practice warrant most attention. A study can be conducted properly, using a sound design and appropriate methodology. However, making recommendations without adequate justification could lead to incorrect inferences in policy and the management of healthcare, and undermine society’s confidence in science.Measures for safeguarding scientific soundness like those often used in biomedical research (eg, trial registration, open data policies and an improved reporting and archiving infrastructureA third of the HSR publications studied gave no recommendations for policy or practice, while another third did not provide an adequate justification for the recommendations. One could argue that HSR is an applied field of research, and that its ultimate goal should be to contribute to better health services and systems; researchers should therefore take responsibility for providing guidance to those who can act on the research findings instead of leaving them empty-handed. On the other hand, health services researchers may feel more comfortable committing to a more traditional interpretation of the role of academics, refraining from normative judgement. If the latter is the dominant viewpoint, the HSR community needs to consider the role of scientific evidence in helping decision makers address the challenges they face, and informing policies and practices. Internationally, the HSR community has been promoting further strengthening of the link between HSR and practice.In biomedical research, research being ‘new’ might contribute to a confused assessment of implications.The HSR field currently seems to adhere to the norms and expectations set by the biomedical field, even though HSR is multidisciplinary, and differences in approach and type of methodology pose serious challenges to observing these norms. Therefore, the HSR community needs to further define specific scientific norms appropriate to the field.Scientific norms are developed through the forum of a scientific community.QRPs in the reporting of messages and conclusions occur frequently in peer-reviewed international scientific HSR publications from Dutch HSR institutions. These QRPs differ in severity and cannot always be qualified as wrongful, but they do ‘raise questions’. To ensure the applicability of HSR research in policy and practice, the HSR field should reflect on scientific norms for the reporting of conclusions and the inclusion of recommendations for policy and practice. Our study can serve as an empirical basis for continuous critical reflection on the current state of research, and encourage debate on how to systematically advance the reporting of messages and conclusions in HSR.


Background: This investigation has been carried out to evaluate the knowledge, attitudes, and practices toward antibiotic resistance and antibiotic use among community pharmacists in Italy and to investigate their influencing factors. Methods: A cross-sectional telephone survey using a semi-structured interview was performed between September 2018 and April 2019 among a random sample of community pharmacists. Results: Almost two thirds (61.5%) correctly answered that the overuse of antibiotics in primary care, hospital settings, and veterinary medicine is a significant cause of antibiotic resistance. Males, those who worked a lower number of hours per week, and those who acquired information through scientific journals and educational activity were more likely to know that the overuse of antibiotics causes antibiotic resistance. More than two thirds of those pharmacists (70.8%) often or always inform the public about the risks of antibiotic resistance. Those who have been practicing for a higher number of years were more likely to act in that way, whereas pharmacy directors and those who did not need additional information on antibiotic resistance were less likely to inform the public. Conclusions: Pharmacists need to be aware of the issue of antibiotic resistance and policy makers should promote the implementation of antibiotic use public educational interventions in this setting. The antibiotics inappropriately used for the treatment of infectious diseases, their overuse in the food production industry, and incorrect patient behaviors, have led to the selection of multi-resistant microorganisms. Indeed, the threat of antibiotic resistance is increasing globally, and this has caused many infectious diseases to become untreatable, with considerable increases in treatment complexity, side effects, disability, and mortality ,2. MoreoCommunity pharmacists could play an important role in administering and providing recommendations to patients on antibiotic use, since they are a primary source of healthcare information, in the context of limited physician access, and patients often seek their services directly. The Italian Ministry of Health highlighted the importance of the pharmacists’ engagement in order to prevent the misuse of antibiotics through the implementation of public information activities during their activity . As suchSeveral investigations in different countries have assessed the knowledge, attitudes, and behavior of the general population and physicians regarding antibiotic use ,13,14,15Out of 550 community pharmacists who were contacted, 418 agreed to respond with a participation rate of 76%. Regarding the level of knowledge, a landslide majority of respondents were aware that the overuse of broad-spectrum antibiotics (98.3%), patient self-medication (96.2%), failure to comply with dosage (93.1%), and non-adherence to the antibiotic course (89.8%) were causes of antibiotic resistance. Almost two thirds (61.5%) correctly answered that the overuse of antibiotics in primary care, hospital settings, and veterinary medicine was a cause of antibiotic resistance. The results of the multivariate logistic regression analysis showed that being male  and working a lower number of hours per week  were found to be significantly associated with knowing that the overuse of antibiotics causes antibiotic resistance. Compared with pharmacists who did not receive information or used other sources, the probability of having this knowledge was 4.21 times higher among those who had acquired information through scientific journals (95% CI 1.5–11.82) and was 2.39 times higher among those who had participated in educational activity (95% CI 1.36–3.83)  believed that they could play an important role in these interventions, with a mean value of 7.8 on a scale of 1 to 10. The results of the multivariate linear regression model built to test the variables associated with this attitude, showed that male pharmacists, those who were younger, those who knew that the overuse of antibiotics in primary care, hospital settings, and veterinary medicine was a cause of antibiotic resistance, and those who worked a higher number of hours for week, were more likely to consider their role in educational interventions on antibiotic use important (Model 2 in A large proportion of the respondents (89.4%) had a positive attitude regarding the usefulness of information that they provide on antibiotic resistance, with an average value of 7.6 out of 10. The multivariate linear regression analysis showed that male pharmacists, those who have been practicing for a lower number of years, and those who knew that the overuse of antibiotics in primary care, hospital settings, and veterinary medicine was a cause of antibiotic resistance were more likely to have this positive attitude , type (50.2%), duration of treatment (43.7%), and side effects (35.7%). In addition, almost all (95%) reported that the public asked for antibiotics without a prescription for the treatment of dental infections (47.7%), cystitis (47.2%), sore throats (41.8%), influenza (42.5%), colds (29%), and fever (23.6%) and the main reasons were lack of time for clinical visits (77.1%), previous treatment experience (45.2%), having antibiotics at home (30.7%), and physician unavailable (24.1%). More than two-thirds (70.8%) often or always inform the public about the importance of following the recommended duration and dosage of antibiotic treatment. Multivariate logistic regression analysis showed that pharmacists who often or always informed the public about the risks of antibiotic resistance , those who believed the usefulness of information provided on antibiotic resistance , those who reported that the public sometimes or often asking for advice about antibiotics , and those who reported the public’s self-medication  were more likely to inform the public. Employee pharmacists, compared to owners , and those who received information by educational activity , compared to those who did not receive information, were less likely to have this behavior  often or always did this. Respondents who had been practicing for a higher number of years  were more likely to inform the public about the risks of antibiotic resistance. In addition, directors, compared to owners, , and those who did not need additional information  were less likely to inform the public  heard about the antibiotic resistance from various sources, mainly from educational activity (61.5%), scientific journals (57%), and the Internet (33.6%). A vast majority (79.3%) felt a need for additional information about antibiotic resistance.The present research is the first nationwide analysis in Italy to comprehensively assess knowledge, attitudes, and practices surrounding antibiotic use and antibiotic resistance among community pharmacists, and to also assess the effects of several characteristics.The findings of the survey demonstrated that pharmacists’ knowledge regarding the overuse of antibiotics in primary care, hospital settings, and veterinary medicine as the main cause of antibiotic resistance is lacking. This inadequate knowledge could be translated to a lack of information being disseminated to the public. However, almost all respondents were aware of the main causes of antibiotic resistance, including the overuse of broad-spectrum antibiotics, inconsistent treatment duration, and patient self-medication. The knowledge regarding the main causes of antibiotic resistance was higher than those reported in similar investigations ,19,20,21Regarding the attitudes, the results showed that a significant proportion of study participants believed that the public’s educational interventions on antibiotic use must be incorporated into their activity and that they could play an important role in those kinds of interventions. This positive perception regarding their prominent role in the delivery of antimicrobial stewardship programs has already been reported in other, similar surveys conducted in different countries ,23,24. TIn the overall results regarding the practice performed by the pharmacists, more than two thirds of the sample often or always informed the public about the importance of complying with antibiotics’ therapy durations and dosages, and almost half reported that they often or always outlined to them, the risks of antibiotic resistance. This implies that better education is required on antibiotic use and on the risks of antibiotic resistance to improve their practice. That is of particular importance, due the fact that the majority of respondents reported that the public request antibiotics without a prescription and that the most common reasons cited were lack of time for clinical visits, previous treatment experience, and a physician being unavailable. These findings are in line with those reported in a previous survey conducted by some of us in the same geographic area among the general population . The freAs the present results pointed out, the majority of participants identified educational activity and scientific journals as the two most common sources of information regarding antibiotic resistance, which are considered the most powerful forms of communication of health information. Such sources may provide possible targets for conducting interventions aimed at increasing the knowledge. Indeed, it is very important to acknowledge that these sources have played a vital role in improving the level of knowledge, since when comparing the influence of different sources of information about antibiotic resistance on the level of knowledge, educational activity and scientific journals were significantly associated with pharmacists who knew that the overuse of antibiotics causes antibiotic resistance. This result concurred with the findings of previous studies conducted among different groups of individuals on their level of knowledge related to health issues, which documented the strong impact of acquiring information from these sources ,29,30,31Results from multiple linear and logistic regression analyses showed that several other factors were significant predictors influencing the knowledge, attitudes, and practices of pharmacists. Among the different socio-demographic characteristics of the respondents, age, gender, years of experience, number of hours worked per week, and employment type, were the most important variables. Antibiotic knowledge has been found to be higher in respondents working a lower number of hours worked per week and in males. Those who considered their role in educational interventions on antibiotic use important were more likely to be males and younger, as were respondents who had been practicing for a lower number of years had a positive attitude regarding the usefulness of information that they provided on antibiotic resistance. Those with a higher number of years were more likely to inform the public about the risks of antibiotic resistance. This might be due to that their knowledge in this area relies on experience gained in practice. Finally, directors and employees, compared to owners, respectively, had a more positive attitude regarding the usefulness of information that they provided on antibiotic resistance and were less likely to often or always inform the public about the importance of following the recommended durations and dosages of antibiotic treatments. Participants who reported the public’s self-medication were more likely to often or always inform the public about the importance of complying with therapy duration and dose. This might be because community pharmacists, rather than other health professions, are more likely to perform referrals for health services, combined with the fact that pharmacies are readily accessible to consumers, and therefore, they have the chance to discourage antibiotic self-medication and make the public aware of the risks of antibiotic resistance.This current survey encountered some limitations that deserve to be taken into account while interpreting the findings. First, the cross-sectional nature of the questionnaire did not enable the researchers to establish the direction of results or cause and effect relationships between the dependent and independent variables. Second, like any other similar surveys using a semi-structured telephone interview, the accuracy of the results was heavily dependent on the honesty of the respondents, since some of them might have provided socially desirable responses, which could impact on participants’ true attitudes and practices. Interviewees were reassured that answers would be kept anonymous for analyses and this could have minimized this bias. Third, the interview’s questionnaire was a new tool and was been previously validated. Because the instrument was not validated, reproducibility and consistency were not evaluated. Despite these limitations, this study provides useful information about the need for more antibiotic education in pharmacy training programs in Italy and the strong points were that it was conducted among a random sample in the whole country with a high response rate, and therefore, the findings may be representative of the entire pharmacist population.A cross-sectional survey among a nationally representative sample of community pharmacists in Italy was performed between September 2018 and April 2019. The sample was drawn with a two-stage random cluster sampling strategy. In the first stage 500 community pharmacies located in the three geographical areas  were randomly selected from the national list. In the second stage, from each pharmacy, only one pharmacist  who directly dealt with the public was recruited for interview. The minimum calculated sample size was 323, which was determined using a 70% expected knowledge rate regarding the causes of antibiotic resistance, a confidence interval of 95%, and an error rate of 5%. Considering a non-response rate of 20%, a target sample of 405 pharmacists was finally determined.Data were collected by a semi-structured telephone interview performed by members of the research team that had been trained in the purpose of the study and data collection techniques, and who were familiar with the contents. Prior answering the questions, the nature and the purpose of the study was explained to the pharmacists, as were the data collection methods, that participation was voluntary, and that they could stop at any stage without penalty if they did not wish to continue. Participants were told that the data were collected, processed, and analyzed anonymously, and they were assured of the anonymity and confidentiality of their responses. The pharmacists provided verbal consent after learning about the study and its purpose. No remuneration or gifts were given to participants for taking part in the survey.A two-page questionnaire was used to collect the data, composed of five sections. The first section collected socio-demographic and professional characteristics, including gender, age, marital status, year of graduation, number of years in practice, and practice size. The second section assessed the pharmacists’ knowledge about the causes of antibiotic resistance, such as overuse of antibiotics, self-medication, and non-compliance with recommended dose or duration of treatment. The knowledge about the overuse of antibiotics as the cause of antibiotic resistance was explored by presenting the following three propositions: (1) The overuse of antibiotics in primary care is a cause of antibiotic resistance; (2) the overuse of antibiotics in hospital settings is a cause of antibiotic resistance; (3) the overuse of antibiotics in veterinary medicine is a cause of antibiotic resistance. These questions had “Yes,” “No,” and “Do not know” response options. The third section included three questions measuring the attitudes towards their role in public educational interventions on antibiotic use. Two questions were scored using a numerical 10-point Likert-type scale with higher values corresponding to a stronger attitude, and one used a 5-point Likert-type scale with response options ranging from “Strongly disagree” to “Strongly agree.” The fourth section collected information about antibiotic dispensation practices and communication with the public regarding antibiotic use and antibiotic resistance. The questions were measured either using a 5-point Likert-type scale ranging from “Never” to “Always” or through multiple-choice alternatives. The fifth section queried about their sources of information about the antibiotic use and if they would prefer to learn more.The survey questions were pretested to a random sample of 20 pharmacists that were not part of the study to ensure the clarity, validity, and ease of use. Ethical approval for the study protocol and questionnaire was sought from the Ethics Committee of the Teaching Hospital of the University of Campania “Luigi Vanvitelli” .t-tests, to evaluate the association between the outcomes of interest and the independents variables. The variables with p-values ≤ 0.25 at univariate analysis were included into multivariate linear and logistic regression models. Finally, a multivariate stepwise procedure was used to estimate the independent association between potential predictors and the following outcomes of interest: pharmacists who known that the overuse of antibiotics in primary care, hospital settings, and veterinary medicine was a cause of antibiotic resistance (Model 1); pharmacists who believed that they could play an important role in educational interventions on antibiotic use (Model 2); pharmacists who believed that it is important that they inform the public about the antibiotic resistance (Model 3); pharmacists who believed that it is important to inform the public about the duration and dosage recommended for the antibiotic treatment (Model 4); and pharmacists who informed often or always the public about the risks of antibiotic resistance (Model 5). The following independent variables were included in all Models: age (continuous), gender , number of years since degree (continuous), number of years in practice (continuous), number of hours worked per week (continuous), employment type , sources of information , and need of additional information about antibiotic resistance . Moreover, the following variables were also included: knowledge that the overuse of antibiotics in primary care, hospital settings, and veterinary medicine is a significant cause of antibiotic resistance  in Models 2 to 5; pharmacists who believed that it is important that they inform the public about the antibiotic resistance (continuous), pharmacists who believed that they could play an important role in educational interventions on antibiotic use (continuous), pharmacists who indicated that the public often ask for advice on antibiotic treatment , and pharmacists who indicated that the public reported self-medication  in Models 4 and 5; pharmacists who often or always informed the public about the risks of antibiotic resistance  in Model 4; and pharmacists who often or always informed the public about the importance of following the recommended duration and dosage of antibiotic treatment in Model 5. The significance level was set at 0.2 for entering and at 0.4 for removing the variables in the stepwise logistic and linear regression models. Odds ratios (ORs) and their 95% confidence intervals (CIs) were estimated from the logistic regression models. Standardized regression coefficients (β) were presented for the linear regression models. All statistical tests were two-tailed, and results were considered to be statistically significant if the p-values were less than or equal to 0.05.Data analyses were conducted using Stata statistical software version 15 . PrimariThis nationwide study reveals the current situation about the knowledge, attitudes, and practices of the Italian community pharmacists in their approach to antibiotic use. It is imperative that pharmacists become aware of the issue of antibiotic resistance and policy makers should promote the implementation of public educational interventions in this setting.


The present contribution deals with the experimental investigation of the time-dependent behavior of a typical overlay concrete subjected to tensile stresses. The latter develop in concrete overlays, which are placed on existing concrete structures as a strengthening measure, due to the shrinkage of the young overlay concrete, which is restrained by the substrate concrete. Since the tensile stresses are reduced by creep, creep in tension is investigated on sealed and unsealed specimens, loaded at different concrete ages. The creep tests as well as the companion shrinkage tests are performed in a climatic chamber at constant temperature and constant relative humidity. Since shrinkage depends on the change of moisture content, the evolution of the mass water content is determined at the center of each specimen by means of an electrolytic resistivity-based system. Together with the experimental results for compressive creep from a previous study, a consistent set of time-dependent material data, determined for the same composition of the concrete mixture and on identical specimens, is now available. It consists of the hygral and mechanical properties, creep and shrinkage strains for both sealed and drying conditions, the respective compliance functions, and the mass water contents in sealed and unsealed, loaded and load-free specimens. Strengthening measures of existing concrete structures by adding concrete overlays  are becoThe behavior of a concrete structure strengthened by an overlay is mainly characterized by overlay volume changes, related restraint effects in both the overlay and substrate concrete as well as the relaxation of the restraint stresses due to the viscoelastic material behavior of concrete. During the curing process, the early age overlay volume changes result from the exothermic process of cement hydration and related temperature changes. The macroscopic volume reduction of concrete caused by cement hydration after initial setting without moisture exchange between concrete and surrounding environment is referred to as autogenous shrinkage . At lateIt is generally accepted that creep of concrete is composed of basic and drying creep. Basic creep is defined as the creep of concrete occurring under sealed conditions, i.e., no moisture exchange with the environment, whereas drying creep is defined as the creep component additionally developing to basic creep in a loaded specimen exposed to drying . MechaniThe conclusions drawn from comparative investigations of compressive and tensile creep are not consistent ,19,20. FSeveral authors ,31,32,33Concerning the non-linearity of tensile creep, it is usually accepted that up to a certain stress/strength ratio the creep strains are proportional to the applied stress, and, above that limit the creep strains disproportionately increase as a result of progressing microcracking. The results of several researchers ,32,41,42Although several researchers investigated the influence of the moisture content on the creep behavior of concrete, there is hardly any information in the literature about the evolution of the moisture content in sealed or unsealed loaded specimens. Wyrzykowski and Lura ,44 proviIn summary, in concrete overlays (i) tensile stresses due to restrained autogenous and drying shrinkage strains develop already at early ages; (ii) the evolution of drying shrinkage strains depends on the decrease of the water content in the overlay due to hydration and migration of moisture between the overlay and the substrate concrete and (iii) the tensile stresses are reduced by tensile creep. In order to capture the described phenomena in the present experimental study on small-scale specimens, the shrinkage and tensile creep behavior of overlay concrete is determined on sealed and unsealed specimens, exposed to drying and/or loaded at concrete ages of 2, 7, and 28 days. All specimens are equipped with multi-ring sensors, embedded in the cement paste matrix, for measuring the evolution of the mass water content. Hence, the impact of the concrete age at load application on the moisture content and the influence of the moisture exchange between specimens and ambient air of lower ambient humidity on the shrinkage and tensile creep behavior of overlay concrete are studied in detail.The present study is connected to a recent study , in whicThe composition of the investigated concrete mixture is given in The air-entraining agent based on synthetic tensides was used to meet the high demands concerning the frost resistance of a concrete overlay (exposure class XF3 according to ). The lit = 0 is referred to the time when cement and water come in contact during mixing. Fresh concrete properties were determined according to the ONR 23303 [The mixing procedure was as follows: Coarse aggregates, sand, and cement were first mixed dry in a rotary pan mixer for a period of 1 minute. Then the solution of air-entraining agent and mixing water was gradually added during the next minute, followed by adding the plasticizer and continuing the mixing for another 3 min. The concrete age at NR 23303  and reveCubes with an edge length of 150 mm for determining the average cube compressive strength,Prisms with dimensions of product-units = single Prisms with dimensions of product-units = single ished in ,Cylinders with 150 mm diameter and 300 mm height for determining the average splitting tensile strength,Cylinders with 150 mm diameter and 450 mm height for determining both the average uniaxial tensile strength and compressive strength,Cylinders with 150 mm diameter and 450 mm height for the compressive creep tests, recently published in [Immediately after determining the properties of fresh concrete and a further short mixing, the following specimens were cast:®-31. About 7 All specimens were cast in steel molds, except for the cylindrical specimens of 450 mm height, which were cast in longitudinally slotted PVC molds. After casting, all specimens were covered with polyethylene sheets and stored in a climatic chamber at The average cylinder compressive strength NR 23303 , and the 12390-6 , howevers C30/37 . Similars C30/37 , the uni2 mm cf. . The tesThe normalized uniaxial tensile strength at concrete ages of 2 and 7 days amounts to about 65% and 94% of the respective strength at 28 days, whereas the respective normalized splitting tensile strength amounts to about 68% and 90% of the respective strength at 28 days. The respective normalized compressive strength amounts to about 51% and 81% of the respective strength at 28 days . These fIn addition, the water desorption isotherm, characterizing the relationship between pore relative humidity and mass water content at constant temperature, was determined on thin concrete slices for 5 different values of ambient relative humidity. The thin concrete slices were obtained from the prisms with dimensions of product-units = single Immediately after demolding, sealing, and installing displacement transducers, autogenous shrinkage was recorded for one specimen from the concrete age of 24 Six specimens each were used for the investigation of basic creep and drying creep in tension and in compression. The specimens were loaded at concrete ages of 2, 7, and 28 days to the load level of 30% of the average uniaxial tensile strength or cylinder compressive strength , respectSimilarly to Wyrzykowski and Lura , the impThe tensile creep specimens were unloaded at the age of 216 days and the measurements were finished at the age of 232 days.At the respective concrete ages at loading, creep and companion shrinkage specimens were equipped with displacement transducers and the creep specimens were mounted on top of each other either in the hydro-pneumatic compressive creep devices (described in detail in ) or in t−1 by means of a linear actuator driven by a servo motor. Each tensile creep device was controlled via a digital controller. The actual tensile load applied to the specimens was measured with a load cell arranged between the linear actuator and the upper connection point of the specimens. Both the upper and lower connection points were designed as spherical calottes. Moreover, the specimens were connected to each other with an adapter, which was designed as a two-sided spherical calotte. Hence, proper alignment of the central axes of the specimens is ensured and possible bending effects in the specimens due to eccentric tensile load application were minimized.After removing the sealing of the specimens for investigating combined autogenous and drying shrinkage and drying creep in tension and compression, the recording of measurement data was started and the creep specimens were loaded up to the prescribed load. The tensile load was applied at a constant loading rate of 1.0 kN sThe longitudinal deformations of both creep and companion shrinkage specimens were measured by means of 3 displacement transducers fixed along the perimeter of each specimen at distances of 120At the center of each cylindrical specimen a, the evurements . The 7 murements , when mourements .Preliminary tensile and compressive tests were performed on specimens with and without embedded MRSs. The results confirmed that the sensor does not influence the measured longitudinal deformations. Moreover, even when the applied tensile load was increased until failure of the specimens, neither preferred failure in the vicinity of the sensor nor a significantly reduced uniaxial tensile strength was observed. Hence, the small reduction of the cross-sectional area due to the MRS was not taken into account.ished in  and are The total strain in sealed loaded specimens consists of the instantaneous elastic strain due to load application, the basic creep strain, and the autogenous shrinkage strain. The total strain in unsealed loaded specimens consists of the instantaneous elastic strain, the basic creep strain, the drying creep strain, and the combined autogenous and drying shrinkage strain.For the sealed specimens, loaded at concrete ages of 2, 7, and 28 days, according to This behavior can be explained as follows: The sealed and unsealed specimens of the creep tests are subjected to low tensile stresses corresponding to 30% of the average uniaxial tensile strength at the respective concrete age at loading, resulting in a positive instantaneous strain. In sealed specimens, the internal relative humidity of concrete decreases with progressing time due to cement hydration and the associated self-desiccation , resultiHowever, with increasing concrete age at exposure to drying, the part of water chemically bound in the hydration products increases. Consequently, the capillary pressure acts on a stiffer solid skeleton , resultiThe creep recovery in tension is also shown in Since it is common practice in the literature and in standards to express creep in terms of the compliance function, the respective compliance function for tensile creep will be determined subsequently. For this purpose, the autogenous shrinkage strain is subtracted from the total strain of the sealed loaded specimens, i.e., iscussed ,38,63,64pression  for the The scatter of the compliance functions for creep in tension, depicted in ant load . On the ant load ,27,64,65ant load ,67. Seveant load ,27,64,65ant load .Measuring of drying shrinkage strains at early concrete ages is associated with additional difficulties, as hydration and drying occur simultaneously and may interact . Moreoveished in , is showAccording to Furthermore, the short term cycle of unloading and reloading of the specimens does not show any effect on the evolution of the mass water content for both the sealed and unsealed loaded specimens cf. a,b.The present contribution focused on the experimental investigation of the time-dependent behavior of a typical overlay concrete subjected to tensile stresses. The latter develop in concrete overlays due to shrinkage of the young overlay concrete, which is restrained by the substrate concrete. Since the tensile stresses are reduced by creep, creep in tension was investigated for sealed and drying conditions for different concrete ages at loading. Because of the dependence of shrinkage on the change of moisture content, in addition, the evolution of the mass water content was determined at the center of each specimen. Together with the experimental results for compressive creep from a previous study, a consistent set of time-dependent material data is now available. It has been determined for the same concrete mixture with the same shape and size of the specimens, the same sealing technique, the same measurement device, the same concrete age at loading and the same load level. Hence, any size effect due to different specimen sizes or any influence of different sealing techniques and measurement devices can be excluded. The set of measurement data consists of the autogenous shrinkage strain, the combined autogenous and drying shrinkage strain, the total strain, determined in tensile and compressive creep tests on sealed and unsealed specimens, loaded at concrete ages of 2, 7, and 28 days to 30% of the respective average uniaxial tensile strength or cylinder compressive strength, the respective compliance functions for creep in tension and compression and the evolution of the mass water content in sealed and unsealed specimens subjected to shrinkage and sustained tensile loading.For early concrete ages at loading, the evolution of the total strain in specimens loaded to 30% of the respective tensile strength of concrete at loading is mainly governed by shrinkage due to hydration and drying. Consequently, the total strain in the sealed and unsealed loaded specimens and the respective shrinkage strain in the load-free companion specimens evolve quite similarly.For early concrete ages at loading, the compliance function indicates a vanishing or even negative tensile creep strain, which was also observed by other researchers. Hence, the usual assumption of the additive decomposition of creep and shrinkage strains is questionable, especially for early concrete ages at loading.At least for the concrete age at loading of 28 days, for both sealed and drying specimens, the compliance for tensile loading is higher than the one for compressive loading. Similarly, the Pickett effect is more pronounced in tension than in compression.Creep recovery in tension is nearly the same for both sealed and drying conditions.The evolution of the mass water content for both sealed and drying conditions does not show any noticeable impact of load-application on the moisture content and, in the long range the results for both sealed and drying specimens, loaded in tension, are within the measuring accuracy of the MRS.The following conclusions can be drawn from the present study:The comprehensive set of material data for the investigated overlay concrete serves as valuable basis for calibrating models for the numerical simulation of the placement of concrete overlays. Appropriately calibrated numerical models will be used in parameter studies for optimizing the placement procedure of concrete overlays, starting from high-pressure water jetting of the substrate surface to the placement of the asphalt layers on the concrete overlay of the strengthened structure. Since the mechanical behavior of a concrete overlay is strongly influenced by additional physical phenomena, like thermal, hygral and chemical processes, a multiphase concrete model provides an appropriate description of the material behavior. In the latter, concrete is considered as a porous material, consisting of a solid skeleton and voids, filled by liquid water, dry air and water vapor. The multiphase model, available for this purpose, is based on the model proposed by Gawin et al. . Recentl


The aim was to gain a better understanding of the prevalence, organ involvement, clinical characteristics and long-term outcomes of medical and surgical treatments of IgG4-related disease (IgG4-RD).n = 28; 49%) or probable  IgG4-RD by histopathological criteria and IgG4 serum concentrations. Patient demographics, type of treatment and outcomes were retrieved from medical records. Patients were designated as being in remission if indicated in the chart and/or symptom- and objective finding-free for >6 months, relapsed if symptoms/findings recurred after remission, active if no remission was achieved during follow-up, and as unable to determine if the duration of follow-up was <60 days or they were lost to follow-up.Query of the Cleveland Clinic pathology database for IgG4 plasma cell staining between 2007 and 2017 yielded 1481 results, of which 57 cases were identified as highly likely (n = 119), half (n = 57) satisfied the IgG4-RD histopathological criteria; 63% were males, age 57.9 ± 14.8 years. The average follow-up was 2.7 ± 2.2 years. The pancreas was the most affected organ in our cohort (26.4%). Almost half of the patients  were managed surgically, 21.1% (n = 12) medically, and 24.6% (n = 14) received both types of treatment. Medical treatment included prednisone (45.6%), MTX (5.3%), AZA (7%) and rituximab (8.8%). Remission was achieved by 77% of patients receiving surgical, 67% receiving medical and 72% receiving both treatments.Of all patients who met the IgG4 staining criteria (+ plasma cells ≥10/high-power field or IgG4+/IgG+ ratio >40%. In our cohort, surgical treatment compared with medical treatment had a higher proportion of remission according to our outcome classification.A histological diagnosis of IgG4-RD could be made in half of the patients who had IgG4 IgG4-related disease is rare, with the pancreas being the most affected organ.+ plasma cell ≥10/high-power field or IgG4+/IgG+ ratio >40%.Histopathological criteria were met in half of cases meeting IgG4In some patients with IgG4-related disease, surgical intervention may be more effective than medical treatment.+ lymphoplasmacytic infiltrate and storiform fibrosis [IgG4-related disease (IgG4-RD) is a rare, multisystem fibro-inflammatory condition, characterized by organ mass lesions, IgG4fibrosis . Early dfibrosis , 6 by alfibrosis , 8. IgG4fibrosis , requiri+ plasma cell cut-offs vary by tissue type and affected organs [However, as a recently recognized disease, ACR-approved criteria for IgG4-RD classification are still pending. There have been several publications on consensus guidelines for the diagnosis or classification of IgG4-RD , 10–13, d organs . For exad organs , 15, butd organs . Additiod organs . The curd organs . Glucocod organs .Here, we conducted a retrospective cohort study of patients with IgG4-RD at Cleveland Clinic from 2007 to 2017, identified by histopathology, to gain a better understanding of its prevalence, patient population, organ involvement, histopathological characteristics and long-term outcomes of treatments.vs surgical specimens was made from the patients’ medical records. Confirmed by the date of the procedure and the date of the pathology report, patients who underwent surgical excision as part of therapy were designated as surgical, and their samples were from their surgical procedure. Patients who underwent only biopsy as part of the diagnostic work-up and who received only medical treatment were classified as medical. Cases were selected based on histopathology, following recently published consensus guidelines for the diagnosis of IgG4-RD [This study was approved by the Cleveland Clinic Institutional Review Board (reference no. 17-367). Patients were identified via a search of the surgical pathology database in Anatomic Pathology at the Cleveland Clinic Foundation between 2007 and 2017, for resected or biopsied pathology specimens that were stained for IgG4. Distinction of pathology reports based on biopsy  IgG4-RD , 19.+ plasma cell cut-offs for each tissue type [+ plasma cell count were classified as probable. If IgG4 serum levels were available, which was the case for 15 patients, the flow sheet from Yamamoto et al. [+ plasma cells with IgG4+ to IgG+ ratio >40% and/or >10 IgG4+ plasma cells/high-power field (hpf) were designated highly likely [IgG4-RD was classified according to previously published criteria , 9, 10 bsue type ; cases wo et al.  was folly likely . An examWe defined medical treatment as use of prednisone, MTX, AZA and rituximab, and recorded the number of medications prescribed for each patient. Surgical treatment was reserved for patients who underwent therapeutic excision of the mass as indicated by the surgery notes and verified by CT scans. Patients who underwent both medical and surgical treatment during the duration of follow-up, such as if the patient was treated medically first before undergoing surgery or received additional medical treatment such as prednisone after surgical removal, were categorized separately as both treatments.Patient age, gender, BMI, pre-existing conditions, presence of allergies, smoking status, alcohol intake, organ involved, type of treatment and outcomes were retrieved from their medical records. Patients were designated as being in remission if indicated in the chart and/or symptom- and objective finding-free for >6 months, relapsed if symptoms or findings recurred after an identified period of remission, active if no remission was achieved during follow-up, and as unable to determine if the duration of follow-up was <60 days or if the patients were lost to follow-up to identify the final outcome. The date of diagnosis for the study was defined as the date of the pathology report that demonstrated the identifying features of IgG4-RD, and the total duration of follow-up was measured from the date of the pathology report indicating IgG4-RD until the last date of a patient visit to the Clinic at the time of chart review. The duration of time until relapse was obtained from the number of days between the date of remission and the best estimate of the date of relapse by a patient visit after previously noted remission.2, Pearson and/or Fisher’s exact test was used to compare categorical variables, and Student’s two-tailed t-test was used to compare continuous variables.The statistical analysis was performed using JMP Pro v.13 . Significance level was set at an α value of 0.05. The χ+ plasma cells ≥10/hpf and/or IgG4+/IgG+ plasma cell ratio >40%  or probable IgG4-RD , based on histopathological criteria. We used the more inclusive criteria of and/or for IgG4+ plasma cells ≥ 10/hpf and/or IgG4+/IgG+ plasma cell ratio >40%, instead of requiring both conditions, because most pathology reports chose to state either the IgG4+ plasma cell count or the IgG4+/IgG+ plasma cell ratio. Also, not all patients had their serum IgG4 level measured. Of the 119 patients, 15 patients had serum levels of IgG4 available in addition to the histopathology data, and were sorted following the guideline provided by Yamamoto et al. [The search of the Cleveland Clinic pathology database for patients whose biopsy or surgical specimen was ordered an IgG4 staining between 2007 and 2017 identified 1481 pathology cases from 1101 patients. We screened for cases positive for tissue IgG4tio >40%  based on2. The racial distribution was 57.9% white and 26.3% African-American (n = 33) of patients; 54.4% (n = 31) of patients had a smoking history, mean 30.1 ± 34.1 pack years, and 45.6% (n = 26) of patients had a history of alcohol use (P = 0.4173), age (P = 0.7623), BMI (P = 0.6568) or race (P = 0.1303). The mean duration of follow-up for patient treatment and outcome after identification of IgG4-RD by histopathology was 2.7 ± 2.2 years.Baseline characteristics of highly likely and probable IgG4-RD patients were analysed in comparison, in addition to the whole group . Of 57 pAmerican . A histoohol use . We founSimilar to previous IgG4-RD reports, the pancreas was the most affected organ in our cohort (26.4%) . Other on = 26) were managed surgically, 21.1% (n = 12) medically, and 24.6% (n = 14) received both types of treatments. Medical treatment included prednisone (45.6%), MTX (5.3%), AZA (7%) and rituximab (8.8%); 58.3% of patients took more than one medication. Remission was achieved by 77% of surgical, 67% of medical, and 72% of recipients of both treatments (n = 6), aorta (n = 3), biliary ducts (n = 4), salivary glands (n = 3), thyroid glands (n = 3), lacrimal glands (n = 1), lungs (n = 1), lymph node (n = 1) and other .Almost half of the patients  who met the IgG4 plasma cell staining criteria (n = 119) satisfied the IgG4-RD histopathological criteria, with 21.1% (n = 12) displaying all three characteristics of lymphoplasmacytic infiltration, fibrosis and obliterative phlebitis. Elevated IgG4 serum levels have recently been shown in a meta-analysis to have a pooled sensitivity of 85% and specificity of 93% [+ plasma cells can be increased in tissue biopsies from a number of other diseases, such as granulomatosis with polyangiitis, multicentric Castleman disease, Rosai–Dorfman disease, marginal zone lymphoma, pancreatic adenocarcinoma [Likewise, it is important to note that only about half of the cases  who who had IgG4+ plasma cells ≥ 10/hpf or IgG4+/IgG+ ratio >40% (n = 119) satisfied the IgG4-RD histopathological criteria. In our study, although not statistically significant, surgical intervention resulted in a higher rate of remission than medical intervention. Patients treated surgically had a better remission rate by 6 months or a longer period of treatment than those with medical-only or both medical and surgical treatments. Our study illustrates the difficulty of making a precise diagnosis of IgG4 RD and the need for prospective studies that can result in better diagnosis and classification criteria and in better treatment strategies.In conclusion, IgG4-RD is a complex, systemic fibro-inflammatory condition that can affect virtually any organ system, with a prevalence of 5.2% of suspected cases. IgG staining criteria alone, in the absence of the other histopathological findings, can be misleading. We found that only about half of the cases  to Chan Mi Lee and Carmen E. Gota.


This paper presents the outcome of a project funded by Beni-suef University targeting the assessment of the addition of carbon nanotubes (CNTs) to reinforced concrete beams on exposure to elevated temperatures. Tests were carried out in compliance to ASTM E119-95a. Besides, pre and post their exposure to elevated temperature tests, the maximum bending capacity of the beams are evaluated. Standard reinforced concrete beams are cast- with and without Carbon Nanotube (CNT). Tests were performed at two temperature levels 400 °C and 600 °C working around temperature ranges expected to have significant effect on concrete endurance, using both one and two hours exposure. Results proved a positive effect for adding CNT to beams at room temperature. This improvement is slightly affected at 400 °C exposure for 2 hr. On the other hand, exposing CNT beams for 600 °C for two hours reduced the beams capacity by 14% compared to a similar reinforced beam without CNT. It is worth notice that CNT was not burnt but suffered de-bonding. Finally, this investigation implies that CNT can be used as an enhancing element to concrete ductility, with no deterioration in other mechanical characteristics on exposure to drastic thermal conditions. Many reinforcing techniques are based on fillers to fill in the pores, connect the components and transfer stresses in concrete. Fiber-reinforced concrete (FRC) is a product out of this bridging concept. Those fibers length scale ranges from micrometers to centimeters, but do not reach Nano voids filling. Nano-additions can modify the packing of Ordinary Portland Cement Concrete, improve its hardened performance3. Several studies on concrete with Nano silica (NS) and carbon Nano fibers (CNF) have been carried out in order to identify their advantages in the fresh and hardened performance5. Theoretically, Nano-fibers should be good candidates to control early age cracking, as the addition of CNF increased 30% flexural strength of fluid pastes and it does not control cracking and even increased it6. Carbon nanotubes (CNTs), known for superb material properties and the elegant structure9, are of great potential to be extensively dispersed into cement filling up the pores and modifying the structures at the Nano scale. In order to mitigate early age cracking, small amounts of micro-fibers can be incorporated11. In order to gain superior comprehension of interaction between CNTs, C-S-H and resulted a systematic evaluation, mechanical enhancement on the method of the CNTs in the concrete system and CNTs bring about the mechanical enhancement necessary a series of reviews can be found18.Concrete components are not perfectly bonded, consequently, pre-cracks and pores often exist in hardened concrete19. Such interfaces will act as crack blunting mechanisms at the very nascent stage crack growth. CNTs can be widely distributed in the concrete paste; in addition, interaction of CNTs with the paste will be more intense than that of the larger fibers.It is expected that using carbon nanotubes shall enhance the concrete mix behavior. It is well known that Concrete as a cementitious composite is held together by a complex network of nanoparticles known as calcium silicate hydrate (CSH). Due to their Nano-scale characteristics, CNTs shall interact most intimately with CSH. The large surface energy, and the large number of atoms present at the nanotube surface shall promote the formation of an interface with C-S-H. Thus, leading to optimum condition for stress transfer. Carbon nanotubes have high flexibility, and are capable of bending in circles, thus, forming bridges crossing the micro- and Nano-cracks developed in the cement composites. CNTs interact with the C–S–H, generating bridges that enable the CNTs to increase the strength of the cement composites, and stitch the concrete crack20. Employed methods mainly involve continuum approaches such as mesh less method21 and finite element method22. Discussions about fire safety issue are rare. Structural void is a critical concern about strength of solid materials such as epoxy, concrete and bonded composites25. Adding fibers to bridge voids or cracks is an effective way to mechanical enhancement29. The materials interface can be quantified by its strength defined as bond quality or adhesion strength31. The bond quality can be measured by multi-scale experiments33 and predicted by molecular dynamics simulations35. It has been revealed that the bilayer materials interface is typically the weakest part in a composite system and is susceptible to external conditioning. In steel bar reinforcement, corruption that degrades bond quality is also a necessary concern37. Nanostructures of the fiber-cement interface38 have been found to be important for adhesion strength. When concrete remains exposed to fire for a long period, losses of its mechanical properties occur39. In the case of unprotected concrete, the mechanical properties decrease dramatically when the concrete is exposed to a high temperature39. A reduction in the fire resistance rating was observed in the reduced cross-section via the good protection layer during elevated temperature exposure tests40. On the other hand agglomeration has to be avoided during mixing42. This article will focus on the effect of elevated temperatures on the CNT reinforced concrete beams. Mechanical characterization is performed pre and post exposure to 400 °C and 600 °C for one and two hours.Multi-scale modeling techniques are developed and applied to simulate material behaviors of CNT-reinforced concrete42.The specimens used were 10 reinforced concrete beams with rectangular cross-sections with a size 150 mm (width) × 150 mm (height) × 700 mm length. Typical reinforcement pattern is used in all beams: 2 bars 8 mm diameter for both top and bottom reinforcement. Stirrups of 8-mm-diameter are used for shear resistance, and are spaced at 8 cm centre to centre as shown in Fig. 41 investigated the optimization of mixing procedure, and thus, sonication was adopted to ensure proper dispersion. The experiment will be divided into two parts. The effects of CNTs on the flexural and shear strength of normal strength concrete were studied. In this experiment, five groups of specimens will be tested under one point loading to determine the flexural and shear strength of concrete. Each group will consist of three rectangular specimens of dimensions 150 × 150 × 700 mm. The first group will act as the control group, with no CNTs, and the other groups will contain 0.05% of CNTs from cement weight. The following table shows the details of the experiment. Optimized samples from above experimental programs will be thermally evaluated according to ASTM 11943 fire exposure testing curve Fig. Special attention is drawn to mixing procedure, to avoid de-agglomeration problems, Extensive earlier work3 full capacity. Sand, dolomite, and cement were dry mixed first. Figures Ordinary Portland cement (OPC) - ASTM Type I- is used in all mixes, along with natural aggregates and tape water. Concrete design compressive strength is 30 MPa. Mixing was performed using a concrete rotating drum mixer of 0.125 m44. Figure Constant quantity of CNT fibres - 0.05% from cement weight- was added to the design mixes. Multi-walled carbon nanotubes (MWCNTs) are hollow tubular channels prepared by an Egyptian team in Beni Suef University, all technical data is detailed in previous publicationFigure Three points flexural tests are performed using a 1000 KN universal testing machine, while elevated temperature tests are conducted using a 1200 °C electrical furnace. Vertical displacements of the tested beams are recorded using a linear variable differential transformer at the middle of the beam, whereas dial gauges were used to measure the vertical displacement at the same location. Strains are monitored at two different locations expected to undergo critical flexural strain and the other at the maximum shear as shown in Fig. Flexure tests results are displayed and compared for both CNT and RC beams. Pre and post-thermal exposure samples are tested to evaluated the loss in flexural capacity of both concrete beams types due to these high ranges of temperature exposure.27, as CNTs can be spread widely in concrete mix; thus, the interaction of CNTs with concrete will be more intense than using larger size fibres8.First crack versus loads are displayed in Fig. Exposure to 400 °C for 1 hour does not have a significant effect on the first crack load, while increasing the fire exposure to 2 hours duration reduced the first crack load to 0.77 of the RC control beam at ambient temperature. Similar reduction is noticed for 600 °C exposure for 1 hour. On the other hand, increasing thermal exposure duration of the 600 °C for 2 hours lead to an earlier observation of the first crack at 0.68 of the crack load of RC control beam.Hence, CNT beam to RC beam first crack load is: 1.35, 1.09 and 0.84, for room temperature and 400 °C for 1 and 2 hours respectively. Exposure to 600 °C for 2 hours has a dramatic effect on first crack load, reaching 0.45 from CNT- beam first crack load at ambient temperature. This can be attributed to the conversion of the CNT to CO2 at high temperature through the reaction of carbon with oxygen from the atmosphere.Figures Figures Comparing the reduction in maximum flexural load, for all cases compared to the control reinforced beam For CNT concrete beams (without CNT) at ambient temperature: exposure of CNT beam to 400 °C for one hour, lead to reduction in maximum flexural load by 11%. Extending temperature exposure for 2 hours increased this reduction to 23%. Exposure to 600 °C for one hour, lead to reduction in maximum flexural load 33%. Extending exposure for 2 hours increased this reduction to 39%. At both 400 °C and 600 °C both CNT beams lost half their original strength.As for shear strains CNT beams expressed higher shear strains Fig. It is worth notice that for 600 °C one hour CNT beams Fig. The maximum shear strain for CNT beam is 71% of the RC beam for 600 °C fire tests two hours exposure, CNT shear strains are 67% from RC beams strains.Figure On the other hand ductility of CNT reinforced concrete beams improved by about 30% from normal temperature conditions, on exposure to 400 °C for two hours, then ductility was lost after 2 hours exposure to 600 °C.The mechanical characterization of all tested CNT and RC beams is summarized in Table The presented is a pioneer research project investigating the elevated temperatures effect on CNT reinforced concrete beams. Discussed results of testing groups of CNT-RC beams lead to the following conclusions:20.Adding a ratio of 0.05% CNT from cement weight lead to an increase of 25% in the load carrying capacity of the tested beams.At normal temperature conditions, CNT controlled shear strains, along with the higher load capacities.CNT noticeably improved the flexure strength of concrete at normal temperature conditions, through improving both: the load carrying capacity, and ductility index. The Nano-scale characteristics of CNTs shall interact most intimately with CSH. Besides, the considerably huge surface energy and large number of atoms on the nanotube surface shall enhance the interface with C-S-H, generating bridges that enable the CNTs to increase the flexural strength of the cement composites and improve the beams ductilityUsing CNT in RC beams increased the first crack load by 35% compared to regular RC beams at ambient temperature. This enhancement was limited to 9% on increasing temperature for 400 °C for one hour exposure on the other hand the beam lost 16% from its first crack load if the duration extended to 2 hours.Two hours exposure to 600 °C has a catastrophic effect on the deterioration of the first crack load, reaching less than half the recorded value for the same beam at ambient temperature.It can be confidently concluded that, high thermal exposure significantly affected the flexural strength of CNT reinforced beams. Although all beams still maintained higher failure load than the corresponding RC beams except at 600 °C two hours exposure, CNT tolerated less maximum load than the corresponding RC -same conditions by 14%, this can be attributed to the complete combustion of CNT inside the beams, and creation of corresponding voids.Although using CNT in RC beams has a positive impact on their flexural crack resistance, exposure to high temperature for long duration (reaching 2 hours) lead to a negative effect on this crack resistance, consequently applying CNT in concrete needs special attention -if intended to be used in buildings susceptible to fire hazards. This negative effect reaches an extreme at 600 °C, as discussed in details later.


Fiber-reinforced polymer (FRP) jacketing/wrapping has become an attractive strengthening technique for concrete columns. Wrapping an existing concrete column with continuous FRP jackets with the fiber in the jacket being oriented in the hoop direction is referred to as FRP full wrapping strengthening technique. In practice, however, strengthening concrete columns with vertically discontinuous FRP strips is also favored and this technique is referred to as FRP partial wrapping strengthening technique. Existing research has demonstrated that FRP partial wrapping strengthening technique is a promising and economical alternative to the FRP full wrapping strengthening technique. Although extensive experimental investigations have hitherto been conducted on partially FRP-confined concrete columns, the confinement mechanics of confined concrete in partially FRP-confined circular columns remains unclear. In this paper, an experimental program consisting of fifteen column specimens was conducted and the test results were presented. A reliable three-dimensional (3D) finite element (FE) approach for modeling of partially FRP-confined circular columns was established. In the proposed FE approach, an accurate plastic-damage model for concrete under multiaxial compression is employed. The accuracy of the proposed FE approach was verified by comparisons between the numerical results and the test results. Numerical results from the verified FE approach were then presented to gain an improved understanding of the behavior of confined concrete in partially FRP-confined concrete columns. Over the past two decades, fiber-reinforced polymer (FRP) has become a favorite material for the strengthening of existing concrete columns. The FRP strengthening technique for a concrete column is predominantly referred to as FRP full wrapping strengthening technique in which an existing deteriorated concrete column is fully wrapped with FRP jacket along the height of the column a. The reAlternatively, partially FRP-confined concrete columns, usually wrapped with FRP strips, refer to FRP-confined concrete columns with discontinuous FRP jackets along their longitudinal axis b. StrengIn real application, however, the lateral confinement can be provided by many different approaches, including simple transverse steel reinforcement e.g., ,29,30), ,30, 29,3To obtain in-depth understanding of partially FRP-confined concrete, the strains and stresses along the generatrix (column height) need to be understood appropriately. The strains distribution along the column height can be tackled by several strain gauges or particle image velocimetry (PIV) technique. However, laboratory tests were incapable of clarifying the distribution of stresses  along the column height, because of the limitations of laboratory measurements. To overcome the obstacles associated with laboratory studies as noted previously, a robust three-dimensional (3D) finite element (FE) approach based on improved concrete plastic-damage model (CDPM)  was emplAgainst the above background, an experimental program was conducted to study axial compressive behavior of circular columns wrapped with CFRP strips. In total, 15 columns were fabricated and tested. The PIV technique was utilized to measure strains in the specimens. The test results of the experimental program were presented and discussed. The improved CDPM was employed for FE analysis of partially FRP-confined concrete columns. The accuracy of the proposed FE approach was verified by comparing the numerical results and the test results. The axial and confining pressure distributions based on numerical results were presented to verify the existing “arching action” and to illustrate the confinement mechanics of partially FRP-confined concrete.A total of 15 cylindrical column specimens were prepared and tested to investigate the behavior of partially FRP-confined circular columns. All specimens had a diameter of 150 mm and a height of 300 mm. The main column parameters investigated in present study are the FRP strip width, clear spacing of two adjacent FRP strips and FRP thickness. The column specimens were wrapped with different numbers of FRP strips  with different widths  and thicknesses . The design of strip number and strip width led to nine different clear spacing ratios in present study . Note thsf′/sf) . The detsf′/sf) , which sNormal concrete made of river sand and natural gravels was utilized to cast the column specimens. Standard cylinders were also cast with the same batch concrete to determine the mechanical properties of the unconfined concrete. After the concrete columns had been cured at room temperature for 28 days, columns were wrapped with carbon FRP (CFRP) strips using a wet layup process, with fibers oriented only in the hoop direction. A 150-mm-long overlapping zone between the starting end and the finishing end of each strip could ensure the fully-developed tensile strength of the FRP.Unidirectional high-tensile-strength carbon fiber sheets, with a nominal layer thickness of 0.167 mm, were utilized to form the FRP strips. FRP tensile tests were conducted to determine the material properties of FRP strips. In the tensile test, a unidirectional one-layer CFRP coupon was employed. The test procedure followed what is specified by the ASTM standard . Five flThe concrete mix proportioning is 1:0.71:2.02:3.59 (cement:water:fine aggregate:coarse aggregate). The properties of unconfined concrete were obtained from compression tests on three standard concrete cylinders in accordance with ASTM C469  and the geoPIV) by tracking the texture  of geoPIV test patches instead of seed particles. A displacement field can then be calculated from the correlation of a reference surface and a displaced or deformed surface. It is worth noting that validation experiments using the PIV code reported by White et al. ..X axis) For the first finding, it is not surprising that both the axial strain and hoop strain at the mid-plain of the two adjacent FRP strips are larger than those at the mid-plain of each FRP strip as the concrete between FRP strips is easier to experience crushing failure. This clearly demonstrates an experimental observation that the ultimate axial strain in partially FRP-confined concrete is larger than that in fully FRP-confined concrete if the axial strain is averaged from mid-height axial shortening. This also implies the ultimate axial strain of partially FRP-confined concrete will be underestimated by the analysis-oriented model  which isParametric studies on partially FRP-confined concrete based on the FE approach can be conducted to gain in-depth understandings on the confinement mechanics. Further research on confinement mechanics of partially FRP-confined concrete wrapped with continuous FRP strip spirals is necessary. To validate the FE approach, pressure measurement technique  is favo(1)The peak stress of confined concrete increases with an increase in width of FRP strip. The ultimate axial strain of concrete, the FRP hoop rupture strain and the slope of the second-segment are independent of the clear spacing of adjacent FRP strips. The compressive strength increases with an increase in the FRP strip thickness while the slope of the second-segment is independent of the strip layer.(2)Based on digital image correlation technique, it is found that both the axial strains and hoop strains are larger at the mid-plain of the two adjacent FRP strips than those at the mid-plain of each FRP strip.(3)A finite element model based on modified concrete damage plasticity model was utilized to simulate the partially FRP-confined concrete. it is found that the FE approach is capable of closely predicting the ultimate axial strain and providing conservative axial compressive strength.(4)Both the axial stress and radial stress at the section edge in the mid-plain of each FRP strip level are larger than those at the mid-plain level of the two adjacent FRP strips. In the mid-plain of each FRP strip, the axial stress distribution along the radial direction is more uniform than that in the mid-plain of the two adjacent FRP strips, indicating that the area of ineffectively confined concrete is largest and the area of effectively confined concrete core is smallest at the mid-plain of the two adjacent FRP strips. This also suggests that the plausibility of the arching action assumption.(5)Both the axial and radial stresses in the mid-plain of each FRP strip are larger than those in the mid-plain of each FRP strip. The deviation of radial stress of concrete increases with an increase in FRP hoop strain. This indicates that the confining stress becomes much more nonuniform with the increase of concrete expansion.(6)The trend of axial strain and hoop strain distributions provided by the FE approach are in accordance with the experimental observations: the axial strain and hoop strain at the mid-plain of the two adjacent FRP strips are larger than those at the mid-plain of each FRP strip.Test results based on the 15 FRP-strengthened cylindrical concrete column partially wrapped with FRP strips have been presented in this paper. Novel PIV technique was adopted to measure axial and hoop strains in the specimens. Never-seen axial and hoop strain variations along the columns were presented. A finite element model based on concrete damage plasticity model was established and validated by the test results. The confinement mechanics of partially FRP-confined concrete was then investigated by the FE approach. Based on the combined test results and numerical results, the following conclusions were drawn:


Chaetomium was reduced, while that of harmful fungi such as Verticillium, Fusarium, and Colletotrichum were increased. The composition of X18 and Y138 fungal community in the same sampling period after continuous cropping was similar, although that of the same sweet potato variety significantly differed with the sampling period. Overall, our results indicate that continuous cropping alters the fungal community structure of the sweet potato rhizospheric soil, such that the content of beneficial fungi decrease, while that of harmful fungi increase, thereby increasing soil-borne diseases and reducing the yield and quality of sweet potato. Furthermore, these effects are different for different sweet potato varieties. Thus, during actual production, attention should be paid to maintain the stability of sweet potato rhizospheric soil micro-ecology through rotation or application of microbial fertilizers and soil amendments to alleviate continuous cropping obstacles.Soil microorganisms play an important role in the ecosystem, and have a certain relationship with the continuous cropping obstacles, which are common with sweet potato. However, there are few reports on the effects of continuous cropping of sweet potato on the microbial community structure in the rhizospheric soil. Here, we investigated the effects of continuous cropping of sweet potato on the fungal community structure in rhizospheric soil, in order to provide theoretical basis for prevention and control of continuous cropping obstacles. This study used X18 and Y138 varieties as experimental materials. Soil samples were collected during the early period of planting and harvest in two consecutive years, and fungi were analyzed using Illumina Miseq. Results showed that the fungi diversity and richness in rhizospheric soil of X18 and Y138 were significantly increased after continuous cropping; the most dominant fungi phylum was Ascomycota, which decreased significantly after continuous cropping. In addition, the content of beneficial fungi such as  Ipomoea batatas (L.) Lam.] is an important global food, feed, and industrial raw material. It is a high-yield and high-efficiency crop that is drought-tolerant and resistant to ridges, exhibiting strong adaptability. The cultivation area and yield of sweet potato are second only to rice, wheat, and corn  and Yizi 138  as experimental materials. And X18 is mostly used for starch processing. Y138 is a variety that people like to eat for its high sugar content. Both are important sweet potato varieties, and have high market demand.The experimental site was located in the Dishang test station of Institute of Cereal and Oil Grops, Hebei Academy of Agriculture and Forestry Sciences at Shijiazhuang, Hebei Province, China . This region has an average temperature of 12.5°C and a mean annual precipitation of 494 mm. The pH of the tested soil was 8.40, the available nitrogen was 85.83 mg kg2, and the planting management was the same as for the field. Rhizospheric soil was collected 30 days after planting and 7 days before harvest, respectively. According to the sampling method of The experiment began in 2015. Sweet potato seedlings were planted on May 6 and harvested on October 7 each year, and planted for two consecutive years. We adopted a random block design, with three experimental repetitions. The ridge distance was 85 cm, seedling spacing was 25 cm for five rows, length of the plot was 6 m, and the area was 25.5 m® Soil DNA Kit  according to the manufacturer’s protocols. The fungal 18S rRNA gene was amplified by PCR  using primers 817F 5′-barcode-817F TTAGCATGGAATAATRRAATAGGA)-3′ and 1196R 5′-TCTGGACCTGGTGAGTTTCC-3′, where barcode was an eight-base sequence unique to each sample. PCR reactions and the extraction and purification of amplicons were performed according to the report by ®3.0 (Life Invitrogen) and every 24 amplicons whose barcodes were different were mixed equally. The pooled DNA product was used to construct Illumina Pair-End library following Illumina’s genomic DNA library preparation procedure. Then the amplicon library was paired-end sequenced (2 × 250) on an Illumina MiSeq platform  according to the standard protocols.Microbial DNA was extracted from the samples using the E.Z.N.A.http://drive5.com/uparse/) and chimeric sequences were identified and removed using UCHIME. The phylogenetic affiliation of each 18S rRNA gene sequence was analyzed by RDP ClassifierHigh-quality sequences were obtained by quality control and filtering of sequence quality as described by The richness and diversity indexes were generated based on Mothur v.1.21.1 , includiThe collected samples were subjected to high-throughput sequencing using the MiSeq platform, and the sequencing results are shown in Analysis of fungal community structure showed that the fungus diversity of sweet potato rhizospheric soil increased significantly after continuous cropping. Additionally, the fungal content of rhizospheric soil was significantly different between X18 and Y138 in different continuous cropping periods.p < 0.05). Moreover, continuous cropping had a greater effect on the Ascomycota content of X18 rhizospheric soil than that of Y138. After continuous cropping for 2 years, the content of Ascomycota of X18 decreased by 21.37 and 37.77%, respectively at the early stage of planting and harvest, and Y138 decreased by 8.13 and 23.28%, respectively. (p < 0.05). The content of Basidiomycota was second to Ascomycota, and also decreased with increase in continuous cropping time; slight increase was observed in the early harvest of 2016. The content of Incertae Sedis and Chytridiomycota increased with continuous cropping of sweet potato. The increment of both was more in X18 rhizospheric soil than in Y138 by 1.4 and 2.3 times of Y138, respectively. Blastocladiomycota is one of the nondominant fungi. After continuous cropping for 2 years, the content of Blastocladiomycota of X18 increased by 0.40 and 0.33% in the early stage of planting and harvest, respectively, and Y138 increased by 0.40 and 0.14%, respectively.At the phylum level , AscomycSome protozoa such as Ciliophora were also detected in the rhizospheric soil of sweet potato.Verticillium, Chaetomium, Colletotrichum, Guehomyces, Fusarium, Volutella, and Sordariales_norank.At the genus level , the domVerticillium, Colletotrichum, Fusarium, and Guehomyces showed a tendency of first decreasing and then increasing with the increase in continuous cropping time. The former three are important plant pathogens .athogens . With thSordariales_norank in rhizospheric soil of X18 and Y138 was not significantly different, with more content in the early stage of planting and less in the early stage of harvest. Moreover, the content of Sordariales_norank in each period of 2016 was significantly increased compared with that in each period of 2015 (p < 0.05), and the content was the highest in the early stage of planting in 2016, accounting for 32.9 and 35.8%, respectively in X18 and Y138.The content of The changes of fungal community structure in the rhizospheric soil of X18 and Y138 after continuous cropping can be seen more clearly from the relative scale value and color change of heatmap , At the The number of fungal OTUs shared by X18 and Y138 samples for each sampling period was 86 . In the We next carried out the PCoA of X18 and Y138 rhizospheric soil fungi . The twoIn the cluster analysis , all samThe Illumina Miseq high-throughput technique was used to analyze the fungal community structure of sweet potato rhizospheric soil after continuous cropping. It was found that the number of OTUs and the Chao, Ace, and Shannon indexes increased after continuous cropping, indicating that sweet potato continuous cropping lead to an increase in the diversity and richness of fungi in the rhizospheric soil, which was consistent with the results of previous studies on the changes of fungal community structure in the rhizospheric soil of Panax notoginseng and American ginseng . Moreovep < 0.05), which was consistent with the results of Verticillium, Chaetomium, Colletotrichum, Guehomyces, Fusarium, Volutella, and Sordariales_norank. Among them, Chaetomium is a beneficial fungus with biocontrol effect . Thus, continuous cropping resulted in an imbalance of fungal community structure in the rhizospheric soil of sweet potato, with a reduction in the beneficial fungal content and increase in the content of harmful or pathogenic fungi. These results are consistent with a previous study (The dominant genus in the X18 and Y138 rhizospheric soil were l effect , and itsn plants , Colletopathogen , and Fusroot rot , were inroot rot , which ius study . Therefous study  can be uContinuous cropping also led to differences in the fungal community composition of the rhizospheric soil among different sweet potato varieties, since the OTU, Ace, Chao and Shannon indexes of X18 after continuous cropping were higher than those of Y138.Based on cluster analysis and PCoA, it was found that the rhizospheric soil fungus community structure of sweet potato was significantly different in different sampling periods after continuous cropping, but the difference between the two varieties was relatively small in the same sampling period, indicating that the sampling period or season also had some influence on the rhizospheric soil fungus community structure .The changes of microbial community structure in rhizospheric soil are crucially related to the continuous cropping obstacles of sweet potato. This study provide a theoretical basis for alleviating the continuous cropping obstacles of sweet potato and study the mechanism of continuous cropping obstacles and biological control of sweet potato root rot, and the study has important practical significance to guide agricultural practices. This will also become an important aspect of sweet potato research. Further research on the application of microbial methods, such as the development of special microbial fertilizer for sweet potato, to prevent and control the continuous cropping obstacles of sweet potato is needed.Continuous cropping obstacles are caused by complex factors within the soil-crop-microbial system, and needs to be solved through a combination of multiple analytical methods. There are many factors related to continuous cropping obstacles, such as soil enzyme activity, soil physical and chemical properties, and root exudates . Some stIn conclusion, continuous cropping of sweet potato led to the most dominant fungi phylum Ascomycota decreased significantly and the fungi diversity and richness in rhizospheric soil of sweet potato increased significantly. In addition, continuous cropping altered the fungal community structure of the sweet potato rhizospheric soil, such that the content of beneficial fungi decreased, while that of harmful fungi increased, thereby increasing soil-borne diseases and reducing the yield and quality of sweet potato. Furthermore, these effects were different for different sweet potato varieties. Thus, during actual production, attention should be paid to maintain the stability of sweet potato rhizospheric soil microecology through rotation or application of microbial fertilizers and soil amendments to alleviate continuous cropping obstacles.The complete data sets generated in our study have been deposited in the NCBI Sequence Read Archive database under accession number SRP215026.ZM, LL, and ZJG designed this experiment. ZL, CL, XW, QT, WJ, and JH executed the experiment. ZYG, MH, and YH finished the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.