BN-Bond-Embedded Triplet Terpolymers with Small Singlet-Triplet Energy Gaps for Suppressing Non-Radiative Recombination and Improving Blend Morphology in Organic Solar Cells

Suppressing the photon energy loss (E_loss ), especially the non-radiative loss, is of importance to further improve the device performance of organic solar cells (OSCs). However, typical π-conjugated semiconductors possess a large singlet-triplet energy gap (ΔE_ST ), leading to a lower triplet state than charge transfer state and contributing to a non-radiative loss channel of the photocurrent by the triplet state. Herein, a series of triplet polymer donors are developed by introducing a BNIDT block into the PM6 polymer backbone. The high electron affinity of BNIDT and the opposite resonance effect of the BN bond in BNIDT results in a lowered highest occupied molecular orbital (HOMO) and a largely reduced ΔE_ST . Moreover, the morphology of the active blends is also optimized by fine-tuning the BNIDT content. Therefore, non-radiative recombination via the terminal triplet loss channels and morphology traps is effectively suppressed. The PNB-3 (with 3% BNIDT):L8-BO device exhibits both small ΔE_ST and optimized morphology, favoring more efficient charge transfer and transport. Finally, the simultaneously enhanced V_oc of 0.907 V, J_sc of 26.59 mA cm^-2 , and FF of 78.86% contribute to a champion PCE of 19.02%. Therefore, introducing BN bonds into benchmark polymers is a possible avenue toward higher-performance of OSCs.

A Nitroxide Radical Conjugated Polymer as an Additive to Reduce Nonradiative Energy Loss in Organic Solar Cells

Nonfullerene-acceptor-based organic solar cells (NFA-OSCs) are now set off to the 20% power conversion efficiency milestone. To achieve this, minimizing all loss channels, including nonradiative photovoltage losses, seems a necessity. Nonradiative recombination, to a great extent, is known to be an inherent material property due to vibrationally induced decay of charge-transfer (CT) states or their back electron transfer to the triplet excitons. Herein, it is shown that the use of a new conjugated nitroxide radical polymer with 2,2,6,6-tetramethyl piperidine-1-oxyl side groups (GDTA) as an additive results in an improvement of the photovoltaic performance of NFA-OSCs based on different active layer materials. Upon the addition of GDTA, the open-circuit voltage (V_OC ), fill factor (FF), and short-circuit current density (J_SC ) improve simultaneously. This approach is applied to several material systems including state-of-the-art donor/acceptor pairs showing improvement from 15.8% to 17.6% (in the case of PM6:Y6) and from 17.5% to 18.3% (for PM6:BTP-eC9). Then, the possible reasons behind the observed improvements are discussed. The results point toward the suppression of the CT state to triplet excitons loss channel. This work presents a facile, promising, and generic approach to further improve the performance of NFA-OSCs.

High-efficiency organic solar cells processed from a real green solvent

The fabrication of organic solar cells (OSCs) depends heavily on the use of highly toxic chlorinated solvents, which are incompatible with industrial manufacturing. The reported alternative solvents such as non-halogenated aromatic hydrocarbons and cyclic ethers are also not really "green" according to the "Globally Harmonized System of Classification and Labelling of Chemicals" of the United Nations. Therefore, processing from real green solvents such as water, alcohols, or anisole will constitute a big breakthrough for OSCs. However, it is fundamentally challenging to obtain high-performance photovoltaic materials processable from these solvents. Herein, we propose the incorporation of a B-N covalent bond, which has a dipole moment of 1.84 Debye, into the conjugated backbone of polymer donors to fabricate high-efficiency OSCs from anisole, a real green and eco-compatible solvent recommended by the United Nations. Based on a newly developed B-N-based polymer, the OSCs with a record-high efficiency of 15.65% in the 0.04 cm² device and 14.01% in the 1.10 cm² device have thus been realized via real green processing.

A Polyfluoroalkyl-Containing Non-fullerene Acceptor Enables Self-Stratification in Organic Solar Cells

The elaborate control of the vertical phase distribution within an active layer is critical to ensuring the high performance of organic solar cells (OSCs), but is challenging. Herein, a self-stratification active layer is realised by adding a novel polyfluoroalkyl-containing non-fullerene small-molecule acceptor (NFSMA), EH-C₈ F₁₇ , as the guest into PM6:BTP-eC9 blend. A favourable vertical morphology was obtained with an upper acceptor-enriched thin layer and a lower undisturbed bulk heterojunction layer. Consequently, a power conversion efficiency of 18.03 % was achieved, higher than the efficiency of 17.40 % for the device without EH-C₈ F₁₇ . Additionally, benefiting from the improved charge transport and collection realised by this self-stratification strategy, the OSC with a thickness of 350 nm had an impressive PCE of 16.89 %. The results of the study indicate that polyfluoroalkyl-containing NFSMA-assisted self-stratification within the active layer is effective for realising an ideal morphology for high-performance OSCs.

Enhancing anaerobic digestion of food waste with granular activated carbon immobilized with riboflavin

Previous studies have shown that anaerobic digestion of food waste can be enhanced by addition of conductive materials that stimulate direct interspecies electron transfer (DIET) between bacteria and methanogens. However, at extremely high organic loading rates (OLRs), volatile fatty acids (VFAs) still tend to accumulate even in the presence of conductive materials because of an imbalance between the formation of fermentation products and the rate of methanogenesis. In this study, granular activated carbon (GAC) immobilized with riboflavin (GAC-riboflavin) was added to an anaerobic digester treating food waste. The GAC-riboflavin reactor operated stably at OLRs as high as 11.5 kgCOD/ (m³·d) and kept VFA concentrations below 69.4 mM, COD removal efficiencies, methane production rates, and biogas methane concentrations were much higher in the GAC-riboflavin reactor than the GAC- and non-amended reactors. Transcripts associated with genes that code for proteins involved in DIET based metabolism were somewhat more highly expressed by Methanothrix in the GAC-riboflavin reactor. However, it is unlikely that riboflavin acted as an electron shuttle to stimulate DIET. Rather, it seemed to provide nutrients that enhanced the growth of microorganisms involved in the anaerobic digestion process, including those that are capable of DIET.

The association between medical student research engagement with learning outcomes

Medical student research engagement has been considered as a critical component of undergraduate medical education. However, evidence on the association between medical student research engagement with learning outcomes is lacking. The objectives of our study are: (1) to outline the landscape of medical student research engagement in China; (2) to explore the association between medical student research engagement and learning outcomes, and whether this association is different among students with different characteristics. A paper questionnaire was developed, piloted, and administered to medical students at 33 medical schools in China. Research engagement was measured by the times students engaged in research projects while learning outcomes referred to learning outcomes contained in the Standards for Basic Medical Education in China. Chi-square tests were used to measure statistical significance between research engagement and the characteristics of participants. We analysed relationships between research engagement and learning outcomes using multivariate linear regression with medical school fixed effects. The overall response rate was 86.7%. 10,062 medical students completed the questionnaire, 55.5% of which had participated in one or more research projects. Research engagement differed by the length of the program, gender, and academic performance. Research engagement was also positively associated with students' overall learning outcomes, especially in the Science and Scholarship domain (once, β = 0.20, P < 0.001; twice or more, β = 0.43, P < 0.001) and the Professionalism domain (once, β = 0.12, P < 0.05; twice or more, β = 0.25, P < 0.01). The relationships between research engagement and learning outcomes differed significantly by gender. Medical student research engagement is significantly positively associated with medical students' learning outcomes, especially in the Science and Scholarship domain and the Professionalism domain. Besides, men benefit more from engaging in research projects, particularly in the Science and scholarship domain.

Prosocial modelling matters: the association between parent and faculty involvement in fighting COVID-19 with medical students' career commitment

BACKGROUND

Role models are essential in medical education, yet empirical research is relatively insufficient on the influence of prosocial modelling on medical students' career commitment. The prosocial behaviour of medical staff involved in the fight against the novel coronavirus disease 2019 (COVID-19) at the beginning of 2020 presents an opportunity to fill the research gap. We explored and compared the different associations of the two most important role models for medical students - parents and faculty- with medical students' career commitment.

METHODS

The cross-sectional study was conducted with 99,559 undergraduate students majoring in clinical medicine in mainland China. Questions were asked to collect information about participants in the battle against COVID-19, medical students' determination to practice medicine after graduation, as well as students' socio-demographic characteristics. Chi-square tests and hierarchical regressions were performed to examine the associations between parent and faculty involvement and students' career commitment.

RESULTS

The results showed statistically significant associations between prosocial modelling during the COVID-19 pandemic in China and students' intention to pursue medical careers. The association of faculty involvement (OR = 1.165, p < .001) with students' career commitment was greater than that of parents (OR = 0.970, p > .05). For faculty involvement, the association was stronger among male students (OR = 1.323, p < .001) and students who were already determined to be doctors (OR = 1.219, p < .001) before the pandemic.

CONCLUSIONS

Our study provides new evidence on the potential roles of parents and faculty in shaping medical students' career commitment. Encouraging faculty to act as positive role models could help medical students increase their intention to become doctors.KEY MESSAGESProsocial modelling could enhance students' intention to pursue medical careers.The association of prosocial behaviour of faculty is larger than that of parents on medical students.Those who have prior medical career commitment are much more likely to persist in the medical profession, and prosocial modelling of faculty is positively associated with their medical career commitment.

[Comparative study of the effects between second toe tibial dorsal artery flap and second toe tibial plantar proper artery flap in repairing finger skin and soft tissue defects]

Objective: To compare the effects between second toe tibial dorsal artery flap (2-TDAF) and second toe tibial plantar proper artery flap (2-TPPAF) in repairing finger skin and soft tissue defects. Methods: A retrospective cohort study was conducted. From January 2019 to June 2020, 27 patients with skin and soft tissue defects at the fingertips with area of 1.5 cm×1.2 cm-2.6 cm×1.8 cm after debridement who met the inclusion criteria were admitted to Suzhou Ruihua Orthopaedic Hospital, including 21 males and 6 females, aged 19-59 (37±10) years. According to flap repair methods used in the defective fingers, the patients were divided into 2-TDAF group (12 cases) and 2-TPPAF group (15 cases). The area of 2-TDAF ranged from 1.5 cm×1.2 cm to 2.5 cm×1.6 cm, and the area of 2-TPPAF ranged from 1.7 cm×1.3 cm to 2.6 cm×1.8 cm. Full-thickness skin grafts from the medial side of the ipsilateral leg were grafted to the wounds in donor sites, and the wounds in donor sites of skin grafts were directly sutured. Flap arterial diameter, flap excision time, flap survival situation of patients in 2 weeks after operation, and follow-up time were recorded. At the last follow-up, the two-point discrimination distance of flap graft site, total action motion (TAM) of the finger joints, and wound healing of the flap donor site were recorded; the Vancouver scar scale (VSS) was used to score the scar in donor area of the second toe and the recipient area of fingers; the appearance and self-satisfaction subscales of the Michigan hand outcomes questionnaire (MHQ) were used to evaluate the affected finger. Data were statistically analyzed with independent sample t test or Fisher's exact probability test. Results: The flap artery diameter of patients in 2-TDAF group was 0.35-0.80 (0.56±0.14) mm and the flap cutting time was (14.0±2.7) min, which were significantly shorter than 0.80-1.35 (1.02±0.16) mm and (19.7±3.4) min in 2-TPPAF group (with t values of 7.81 and 4.79, respectively, P<0.01). The flaps of patients in the 2 groups in recipient areas survived well in 2 weeks after operation, and the wounds in donor areas of flaps of patients in the 2 groups healed well at the last follow-up. There was no statistically significant difference in the postoperative follow-up time, and two-point discrimination distance of flap graft site, TAM of the finger joints, VSS score of scar in the second toe donor site and the finger recipient site, and the appearance and self-satisfaction of MHQ scores of the affected finger at the last follow-up (P>0.05). Conclusions: Compared with 2-TPPAF, 2-TDAF has a shallower anatomical layer and shorter time for surgical flap removal, which can preserve the proper arteries and nerves at the base of the toes and reduce the damage to the donor site.

Therapeutic effect of low frequency electric pulse therapy on cisplatin-based chemotherapy-induced nausea and vomiting in patients with lung adenocarcinoma: A prospective controlled study

To explore the efficacy of low-frequency electric pulse therapy (LFEPT) combined with 2 antiemetics in the prevention and treatment of cisplatin-based chemotherapy-induced nausea and vomiting (CINV) in patients with lung adenocarcinoma. A total of 82 patients with lung adenocarcinoma who received cisplatin-based chemotherapy were randomly divided into the experimental group (n=41) and control group (n=41) by random numerical table method. The experimental group was treated with LFEPT combined with 2 antiemetic drugs (tropisetron hydrochloride and dexamethasone hydrochloride), while the control group was treated with the same 2 antiemetic drugs. Revised index of nausea and vomiting and retching (R-INVR) and Functional Living Index-Emesis (FLIE) scale were used to quantitatively evaluate the symptoms of nausea and vomiting after chemotherapy, and the effect of LFEPT in the prevention and treatment of CINV was observed. The baseline characteristics had no statistical difference between the 2 groups. The degree of nausea reaction, vomiting, and dry retching were similar in 2 groups on the first day after chemotherapy. However, the degree of nausea reaction, vomiting, and dry retching were significantly improved in the experimental group than that of the control group on 2 to 5 days with all P<.05. The score of FLIE had no difference between the 2 groups on the first day after chemotherapy (84.05 vs 82.69, P=.30), and the score was significantly higher in experiment group on day 6 compared with the control group (103.71 vs 89.38, P=.02). The side effects had no difference between the 2 groups. The LFEPT can significantly ameliorate CINV in patients with lung adenocarcinoma, which is worthy of clinical application.

Double-Side Selective Spectral Response Organic Photodetectors for Demultiplexing Optical Signals

Selective spectral response photodetectors (PDs) capable of accurately capturing the color of images have broad applications in industry and academia. Here, we demonstrate filter-free, wavelength-selective detection organic photodetectors (OPDs) with two distinct response ranges and having the planar bilayer heterojunction device structure by employing either a (semi-)transparent anode or a cathode as the incident light window. The resultant OPDs exhibit a responsivity of 51 mA W^-1 in the range 300-650 nm and 11 mA W^-1 in the range 650-850 nm under top illumination condition. Similarly, the devices show a responsivity of 2 mA W^-1 for the short-wavelength region and 131 mA W^-1 for the long-wavelength region when under bottom illumination condition, indicating a high responsivity ratio that meets the requirements for selective detection. Hence, our individual device not only works in either visible or NIR range but also provides narrowband detection with spectral widths down to 100 nm in the NIR range. The working mechanism of spectral selectivity is identified through quantitative analysis of the external quantum efficiency (EQE) spectra using optical modeling when compared to the OPDs with bulk heterojunction structure, thus clarifying the general validity of the device design concept. Finally, our OPDs can demultiplex intermixed optical signals from the light-communication system successfully. Our results should inspire new studies on the device design concept and new applications of OPDs.

The relationship between medical student engagement in the provision of the school's education programme and learning outcomes

INTRODUCTION

Student engagement in the provision of the school's education programme (educational student engagement) plays an important role in quality assurance in medical education. However, little is known whether this specific type of student engagement has effects on the learning outcomes for the involved medical students.

METHODS

This study was based on a national-wide survey in China among medical students with 123,055 responses. The questionnaire was designed using international and Chinese national standards. T-test, analysis of variance, multivariate regression, and regression with interaction terms were used.

RESULTS

Educational student engagement was positively associated with medical students' learning outcomes in Clinical Practice, Science and Scholarship, Health and Society, and Professionalism. Besides, the influence was heterogeneous among participants at different learning phases. Learning outcomes in Clinical Practice were strongly associated with educational student engagement efficiently at the Clinical Medical Education and the Clerkship Rotation phases, and learning outcomes in Science and Scholarship were best correlated with the Clerkship Rotation phase.

CONCLUSION

Educational student engagement is positively associated with the learning outcomes, with the greatest effect on learning outcomes in Clinical Practice and the least effect in Professionalism. Besides, it has a greater impact on medical students at senior learning phases.

Nomograms for Predicting Medical Students' Perceptions of the Learning Environment: Multicenter Evidence From Medical Schools in China

Medical students' perceptions of the medical school learning environment (MSLE) have an important impact on their professional development, and physical and mental health. Few studies reported potential factors that influenced medical students' perceptions of MSLE. Thus, the main goal of this study was to identify influencing factors for medical students' perception levels of MSLE. The perception levels of MSLE were assessed by the Johns Hopkins Learning Environment Scale. The univariate and multivariate logistic regression analyses were performed to identify significant predictors for the perceptions of MSLE. The nomograms were established to predict medical students' perception levels of MSLE. In the multivariate logistic regression model, gender, university category, grade, mother education level, learning environment of schools, interests in medicine, and Kolb learning experience were significantly associated with medical students' perceptions of MSLE. Correspondently, the nomograms were built based on significant variables identified by the univariate logistic regression analysis. The validation of the nomograms showed that the model had promising predictive accuracy, discrimination, and accordance (area under the curve (AUC) = 0.751). This study identified influencing factors of medical students' perceptions of MSLE. It is essential to implement corresponding interventions to improve medical students' perceptions.

Still want to be a doctor? Medical student dropout in the era of COVID-19

This research examines the intention of undergraduate medical students to withdraw from the medical profession and pursue a career in a different field upon graduation during COVID-19. We leverage the first and most comprehensive nationwide survey for medical education in China, which covered 98,668 enrolled undergraduate students from 90 out of 181 Chinese medical schools in 2020. We focus on these students' self-reported intention to leave the healthcare industry (the "dropout intention") before and after the outbreak of the epidemic. We also designed a randomized experiment to test whether and to what extent medical students dropout intention responded to an information nudge that highlighted the prosociality of health professionals in the fight against the virus. Results from a difference-in-differences model and a student fixed effect model suggest that after the onset of COVID-19, the proportion of Chinese undergraduate medical students with a dropout intention declined from 13.7% to 6.8%. Furthermore, the nudge information reduced the intent-to-drop-out probability by 0.8 additional percentage points for students in their early college years. There was large heterogeneity underneath the treatment effect. Specifically, we find that prior dropout intention and exposures to COVID-19-related information tended to mitigate the nudge effects. Data on students' actual dropout outcomes support our findings.

Toward High-Efficiency Organic Photovoltaics: Perspectives on the Origin and Role of Energetic Disorder

The power conversion efficiency of organic photovoltaics is strongly limited by relatively large energy loss, which is partially due to the disordered nature of organic semiconductors. This disordered nature not only hinders the rational design of molecules with excellent photophysical properties but also prevents a more thorough understanding of the inherent link between microscopic parameters and physical phenomena. In this Perspective, we demonstrate that the injection-dependent emission line-shape in organic semiconductors is primarily associated with a state-filling effect, where the extent of spectral blue-shift can be a strong indicator for energetic disorder. Molecular geometry with rigidity and coplanarity not only promotes preferential face-on stacking that narrows the energetic distribution of subgap states but also impedes torsional deformations of the conjugated backbone away from planarity, thereby facilitating larger π-electron delocalization. These structural characteristics explain the seemingly contradictory high radiative efficiency of low-bandgap nonfullerene molecules, providing promising molecular design strategies to realize high-efficiency organic photovoltaics.

Stratification of Health Professional Education and Its Funding Disparities: Evidence From China During the Period of 1998–2017

Background: The finance of health professional education (HPE) is of immense importance for effective and sustainable health systems, yet relevant empirical research was scarce due to the lack of financial data. The study aimed to bridge the gap by presenting the scenario of finance for health professional institutions (HPIs) of different tiers in China and exploring how the stratification of institutions affected their funding disparities.

Methods: The study employed data collected from the Ministry of Education in China, and selected the HPIs mainly based on the World Directory of Medical Schools. The funding levels and disparities of China's HPIs during the period (1998–2017) were analyzed with descriptive statistics, and the indicators of funding per institution and funding per student were both considered. The average funding in HPIs was presented by tiers, and the Gini coefficient and Theil index were employed to describe the differences in financing among HPIs over the span.

Results: The study found that the number of HPIs has kept growing over the past two decades, with both the funding per institution and the funding per student increasing steadily. Specifically, the average funding per institution of the three tiers increased by 31.5 times, 13.4 times, and 10.5 times separately, with the first-tier universities having an absolute advantage compared to lower tiers. As for the financing disparities among HPIs, the Gini coefficient of the funding per institution maintained to be over 0.5, with the third-tier institutions scoring the highest, while the Gini coefficient of the funding per student all ranged approximately from 0.2 to 0.3. Through the decomposition of the inequalities measured by the Theil index, the share of the between-tier difference in per-institution funding grew from 29.7 in 1998 to 77.9% in 2017.

Conclusions: The funding disparities between tiers of HPIs in China gradually became more accentuated, with the top-tier institutions taking up the largest share. Although the stratified development in HPE has posed a challenge to the unified quality assurance of medical personnel training, it may also be regarded as an effective pathway for developing countries like China to achieve stable development in health professional education.

An update on current EPAs in graduate medical education: A scoping review

The purpose of this scoping review is to update the recent progress of EPAs research in GME, focusing on the topical concern of EPAs effectiveness, and to provide a reference for medical researchers in countries/regions interested in introducing EPAs. Guided by Arksey and O'Malley's framework regarding scoping reviews, the researchers, in January 2021, conducted a search in five databases to ensure the comprehensiveness of the literature. After the predetermined process, 29 articles in total were included in this study. The most common areas for the implementation and evaluation of EPAs were Surgery (n = 7,24.1%), Pediatric (n = 5,17.2%) and Internal medicine (n = 4,13.8%), a result that shows a relatively large change in the research trend of EPAs in the last two years. Prior to 2018, EPAs research focused on internal medicine, psychiatry, family medicine, and primary care. The articles in the category of EPAs implementation and evaluation had four main themes: (1) validation of EPAs (n = 16,55.2%); (2) describing the experience of implementing EPAs (n = 11,37.9%); (3) examining the factors and barriers that influence the implementation and evaluation of EPAs (n = 6,20.6%); and (4) researching the experiences of faculty, interns, and other relevant personnel in using EPAs. Training programs were the most common EPAs implementation setting (n = 26,89.6%); direct observation and evaluation (n = 12,41.4%), and evaluation by scoring reports (n = 5,17.2%) were the two most common means of assessing physicians' EPA levels; 19 papers (65.5%) used faculty evaluation, and nine of these papers also used self-assessment (31.0%); the most frequently used tools in the evaluation of EPAs were mainly researcher-made instruments (n = 37.9%), assessment form (n = 7,24.1%), and mobile application (n = 6,20.7%). Although EPAs occupy an increasingly important place in international medical education, this study concludes that the implementation and diffusion of EPAs on a larger scale is still difficult.

Twelve tips for teaching medical students online under COVID-19

Universities worldwide are pausing in an attempt to contain COVID-19's spread. In February 2019, universities in China took the lead, cancelling all in-person classes and switching to virtual classrooms, with a wave of other institutes globally following suit. The shift to online platform poses serious challenges to medical education so that understanding best practices shared by pilot institutes may help medical educators improve teaching. Provide 12 tips to highlight strategies intended to help on-site medical classes moving completely online under the pandemic. We collected 'best practices' reports from 40 medical schools in China that were submitted to the National Centre for Health Professions Education Development. Experts' review-to-summary cycle was used to finalize the best practices in teaching medical students online that can benefit peer institutions most, under the unprecedented circumstances of the COVID-19 outbreak. The 12 tips presented offer-specific strategies to optimize teaching medical students online under COVID-19, specifically highlighting the tech-based pedagogy, counselling, motivation, and ethics, as well as the assessment and modification. Learning experiences shared by pilot medical schools and customized properly are instructive to ensure a successful transition to e-learning.

Funding of health professional education: China's 20-year process and a global comparison

CONTEXT

Funding is an essential requirement for ensuring the quality of health professional education worldwide. Adequate funding is of immense significance in training health professionals. Due to the difficulty of accessing relevant data, quantitative research of the kind is scarce.

OBJECTIVES

This study aims at analysing the trends of funding levels and funding sources for health professional institutions in China spanning the past 20 years and making a global comparison.

METHODS

We used data from Ministry of Education (MOE) of the People's Republic of China to analyse its funding level and structure of funding sources of health professional education in China during 1998-2017. When analysing funding level, we used two indicators: total funding and funding per student. We chose the United States, and analysed its funding level and structure to allow easy comparison to the situation in China. The data from a Lancet report (Lancet, 376, 2010, 1923) were also used to analyse global funding status to make an international comparison.

RESULTS

Funding levels of health professional institutions in China has increased significantly in the past 20 years, while the average annual growth rate of funding per student (4.5%) is lower than that of total funding (19.9%). In terms of the structure of funding sources, fiscal appropriation accounts for 51.1% on average, and tuition, fees and scientific research income explains 37.0%.

CONCLUSION

From 1998 to 2017, the total funding and funding per student of HPE in China increased continuously, and the total funding increased at a faster rate. The increase in funding of HPE in China is closely related to the efforts of the Chinese government and the implementation of relevant policies. Even so, funding of HPE in China is likely to remain relatively low compared to other countries.

Students' initial perspectives on online learning experience in China during the COVID-19 outbreak: expanding online education for future doctors on a national scale

BACKGROUND

During the early stage of COVID-19 outbreak in China, most medical undergraduate programs have to eventually embrace the maneuver of transferring to nearly 100% online-learning as a new routine for different curricula. And there is a lack of empirical evidence of effective medical education curriculum that has been completely implemented in an online format. This study summarizes medical students' perspectives regarding online-learning experience during the COVID-19 outbreak and presents reflection on medical education.

METHODS

From February 21st to March 14th, 2020, the authors conducted survey of a nationally representative sample of undergraduate medical students from 90 medical schools in China. Participant demographics and responses were tabulated, and independent sample t-tests as well as multiple logistic regression models were used to assess the associations of demographic characteristics, prior online learning experience, and orientation with students' perspectives on the online learning experience.

RESULTS

Among 118,030 medical students participated in the survey (response rate 52.4%), 99,559 provided valid data for the analysis. The sample is fairly nationally representative. 65.7% (65,389/99,559) supported great orientation and 62.1% (61,818/99,559) reported that they were satisfied with the ongoing online-learning experience. The most common problem students would encounter was the network congestion (76,277/99,559; 76.6%). Demographics, learning phases, and academic performance were associated with online-learning engagement and perceptions. Formal orientation and prior PU (perceived usefulness of online learning) were significantly positively associated with the satisfaction and evaluation of the online learning experience (p <  0.001).

CONCLUSIONS

Data from this national survey indicates a relatively positive role of online learning as a formal teaching/learning approach in medical education. Considerations should be made regarding such application in aspects of students' different learning phases. We suggest that further policy interventions should be taken from technological, organizational, environmental, as well as individual aspects, to help improve the outcome of online learning for future doctors.

Safety and Immunogenicity of a Recombinant Adenovirus Type-5-Vectored Coronavirus Disease 2019 (COVID-19) Vaccine With a Homologous Prime-Boost Regimen in Healthy Participants Aged ≥6 Years: A Randomized, Double-Blind, Placebo-Controlled, Phase 2b Trial

BACKGROUND

We assessed the safety and immunogenicity of a recombinant adenovirus type-5 (Ad5)-vectored coronavirus disease 2019 (COVID-19) vaccine with homologous prime-boost regimens in healthy participants aged ≥6 years.

METHODS

In this randomized, double-blind, placebo-controlled trial, participants received vaccine or placebo 56 days apart. Enzyme-linked immunosorbent assay (ELISA) antibodies to the receptor binding domain (RBD) and pseudovirus neutralizing antibodies were detected. Adverse events were monitored for 28 days following each vaccination.

RESULTS

A total of 430 participants were enrolled in the study, with 30 participants aged 18-55 years (MID cohort), 250 aged ≥56 years (OLD cohort), and 150 aged 6-17 years (MIN cohort). Ad5-vectored COVID-19 vaccine induced significant RBD-specific ELISA antibodies that decreased with increasing age, with geometric mean titers (GMTs) of 1037.5 in the MIN cohort, 647.2 in the MID cohort, and 338.0 in the OLD cohort receiving 5 × 1010 viral particles on day 28 following boost vaccination. Pseudovirus neutralizing antibodies showed a similar pattern, with GMTs of 168.0 in the MIN cohort, 76.8 in the MID cohort, and 79.7 in the OLD cohort. A single dose in children and adolescents induced higher antibody responses than that elicited by 2 doses in adults, with GMTs of 1091.6 and 96.6 for ELISA antibody and neutralizing antibody, respectively. Homologous prime-boost vaccination was safe and tolerable.

CONCLUSIONS

Ad5-vectored COVID-19 vaccine with a single dose was safe and induced robust immune responses in children and adolescents aged 6-17 years. A prime-boost regimen needs further exploration for Ad5-vectored COVID-19 vaccine.Ad5-vectored COVID-19 vaccine with a single dose was safe and tolerated, and induced robust immune responses in children and adolescents aged 6-17 years. The boosting effect on immune responses of the homologous prime-boost regime given 56 days apart was limited.

CLINICAL TRIALS REGISTRATION

NCT04566770.

In Vitro Activities of Tigecycline in Combination with Amikacin or Colistin Against Carbapenem-Resistant Acinetobacter baumannii

Carbapenem-resistant Acinetobacter baumannii (CRAB) has been a common pathogen of nosocomial infections and severely threatened the public health for decades. Tigecycline is a new type of antibacterial glycylcycline and minocycline derivative and has been used to treat CRAB in clinical practice. However, the synergistic effects of tigecycline in combination with other antibiotics including colistin or amikacin remain unclear. A total of 216 CRAB isolates were collected from multiple body parts of different patients. The gene types of these isolates were analyzed and their resistance to carbapenems was determined by Etest. Broth microdilution method was utilized to evaluate the minimum inhibitory concentration (MIC) of each sample. Checkerboard screening technique was performed to demonstrate the synergistic effects of antibiotics and fractional inhibitory concentration index (FICI) was established. Therefore, the joint treatment of tigecycline and colistin (1:1) could effectively improve the sensitivity of AB to antibiotics. OXA-24-like isolates were more sensitive to the combination of tigecycline and amikacin. On the other hand, OXA-23-like isolates were more sensitive to the combination of tigecycline and colistin. Tigecycline exhibited synergistic effects with amikacin and colistin to inhibit CRAB.

Impact of percutaneous poking reduction combined with minimally invasive plate internal fixation on foot function and complications of patients with Sanders type II and III calcaneal fractures

OBJECTIVE

To investigate the impact of percutaneous poking reduction (PPR) combined with minimally invasive plate internal fixation on foot function and complications of Sanders type II and III calcaneal fractures (CFs).

METHODS

In this prospective study, 76 patients with Sanders type II and III CFs were randomly divided into the control group (n=38, "L" incision open reduction and plate internal fixation) and the study group (n=38, PPR combined with minimally invasive plate internal fixation (MIPIF)). The operation related indexes, skin necrosis rate, Gissane angle, Bohler angle, calcaneal height and ankle-hindfoot score before and after the operation were compared between the two groups. Complications of the two groups were recorded.

RESULTS

Compared with the control group, the operation time of the study group was significantly prolonged, but the intraoperative blood loss was significantly reduced, and the fracture healing time and hospitalization time were significantly shortened (P<0.05). The skin necrosis rate of the study group was slightly lower than that of the control group without statistical significance (P>0.05). The Gissane angle, Bohler angle and calcaneal height of the two groups increased 6 months after the operation, and the changes in the study group were more obvious than those in the control group (P<0.05). Six months after the operation, the ankle-hindfoot scores of the two groups significantly increased, and the changes of the study group were more significant than that of the control group (P<0.05). The total incidence of postoperative complications in the study group was significantly lower than that in the control group (P<0.05).

CONCLUSION

PPR combined with MIPIF can significantly promote the healing of Sanders type II and III CFs and the recovery of the Gissane angle and Bohler angle, effectively improve the foot function of patients and induce fewer complications, which is worthy of clinical promotion.