A graphene-like hollow sphere anode for lithium-ion batteries

We report a flash Joule heating method for the rapid preparation of graphene-like materials. The L-GHS exhibited a uniform diameter of 200 nm and an ideal specific surface area of 670 m2 g-1. Meanwhile, the specific capacity of L-GHS remained at 942 mA h g-1 after 600 cycles (1 A g-1), which shows excellent electrochemical performance.

Sensitive Organic Photodetectors With Spectral Response up to 1.3 µm Using a Quinoidal Molecular Semiconductor

Detecting short-wavelength infrared (SWIR) light has underpinned several emerging technologies. However, the development of highly sensitive organic photodetectors (OPDs) operating in the SWIR region is hindered by their poor external quantum efficiencies (EQEs) and high dark currents. Herein, the development of high-sensitivity SWIR-OPDs with an efficient photoelectric response extending up to 1.3 µm is reported. These OPDs utilize a new ultralow-bandgap molecular semiconductor featuring a quinoidal tricyclic electron-deficient central unit and multiple non-covalent conformation locks. The SWIR-OPD achieves an unprecedented EQE of 26% under zero bias and an even more impressive EQE of up to 41% under a -4 V bias at 1.10 µm, effectively pushing the detection limit of silicon photodetectors. Additionally, the low energetic disorder and trap density in the active layer lead to significant suppression of thermal-generation carriers and dark current, resulting in excellent detectivity (Dsh *) exceeding 1013 Jones from 0.50 to 1.21 µm and surpassing 1012 Jones even at 1.30 µm under zero bias, marking the highest achievements for OPDs beyond the silicon limit to date. Validation with photoplethysmography measurements, a spectrometer prototype in the 0.35-1.25 µm range, and image capture under 1.20 µm irradiation demonstrate the extensive applications of this SWIR-OPD.

Effect of internal phase particle size on properties of site mixed emulsion explosive at plateau environment

To study the effect of internal particle size on the microstructure properties and thermal decomposition characteristics of site mixed emulsion explosive at different altitudes. Site mixed emulsion explosive was prepared with different shear rate. The particle size, viscosity, sensitized bubbles, detonation velocity and peak pressure of the emulsion explosive were tested after stored at different simulated altitudes. The thermal decomposition characteristics of emulsion matrix prepared at three different rotational speeds were measured by thermogravimetric analyzer and kinetic analysis was performed by non-isothermal model Kissinger-Akah-Sunose (KAS) method. The results show that with the increase in altitude, the internal phase size showed a trend of first increasing and then decreasing, and the number of sensitized bubbles within the emulsion explosive decreases. At an altitude of 0 m, the detonation velocity and peak overpressure of the emulsion explosive prepared by 1600 r min-1 increased 4.78% and 29.09%, respectively compared with 1200 r min-1, and at an altitude of 4500 m, the detonation velocity increased 11.87%, the peak overpressure increased 43.98%. The thermal decomposition activation energy of the emulsion matrix at 1600 r min-1 increased 13.14% compared to 1200 r min-1. It shows that in the production of site mixed emulsion explosive at high altitude, reducing the particle size of the internal phase of emulsion explosives in a certain range can effectively improve the performance of emulsion explosives.

The trajectory and transition pattern of intention to practice medicine among medical students in China

There has been a growing concern about the career intentions (whether medical students have the intention to practice medicine) due to the increasingly serious problem of medical students attrition. Career intentions have the potential to promote medical students' career commitment and encourage them to stay in the medical profession. Moreover, a series of dynamic career intentions during medical education can be served as an early guide to the medical students' future career choices (whether medical students finally choose to practice medicine). However, few studies focus on the dynamics of career intentions among medical students. In this study, we utilized data from a large-scale national survey of medical students conducted in China from 2020 to 2022 to curve the trajectory of the intention to practice medicine among medical students during their undergraduate medical education by using multilevel growth model. Furthermore, we applied latent Markov model to estimate the transition matrix of the intention across each academic year during the undergraduate medical education. Our findings revealed a trajectory curve with a peak during the second year in the intention to practice medicine. In addition, we identified three latent states of career intention including "strong intention", "wavering" and "weak intention", and further found two distinct transition patterns between individuals with strong career intentions and those without strong career intentions. The transition patterns play a crucial role in understanding the changes in the trajectory of medical students' intentions and determining the optimal timing for interventions to prevent medical student attrition. Our study offers a comprehensive understanding for the dynamics of the career intention among medical students, which has practical implications for medical educators and institutions to address the issues of medical student attrition.

Effect of different hydrogen evolution rates at cathode on bioelectrochemical reduction of CO2 to acetate

Microbial electrosynthesis (MES) offers a promising approach for converting CO2 into valuable chemicals such as acetate. However, the relative low conversion rate severely limits its practical application. This study investigated the impact of different hydrogen evolution rates on the conversion rate of CO2 to acetate in the MES system. Three potentials (-0.8 V, -0.9 V and -1.0 V) corresponding to various hydrogen evolution rates were set and analyzed, revealing an optimal hydrogen evolution rate, yielding a maximum acetate formation rate of 1410.9 mg/L and 73.5 % coulomb efficiency. The electrochemical findings revealed that an optimal hydrogen evolution rate facilitated the formation of an electroactive biofilm. The microbial community of the cathode biofilm highlighted key genera, including Clostridium and Acetobacterium, which played essential roles in electrosynthesis within the MES system. Notably, a low hydrogen evolution rate failed to provide sufficient energy for the electrochemical reduction of CO2 to acetate, while a high rate led to cathode alkalinization, impeding the reaction and causing significant energy wastage. Therefore, maintaining an appropriate hydrogen evolution rate is crucial for the development of mature electroactive biofilms and achieving optimal performance in the MES system.

Riboflavin-loaded carbon cloth aids the anaerobic digestion of cow dung by promoting direct interspecies electron transfer

Cow dung generates globally due to increased beef and milk consumption, but its treatment efficiency remains low. Previous studies have shown that riboflavin-loaded conductive materials can improve anaerobic digestion through enhance direct interspecies electron transfer (DIET). However, its effect on the practical anaerobic digestion of cow dung remained unclear. In this study, carbon cloth loaded with riboflavin (carbon cloth-riboflavin) was added into an anaerobic digester treating cow dung. The carbon cloth-riboflavin reactor showed a better performance than other two reactors. The metagenomic analysis revealed that Methanothrix on the surface of the carbon cloth predominantly utilized the CO2 reduction for methane production, further enhanced after riboflavin addition, while Methanothrix in bulk sludge were using the acetate decarboxylation pathway. Furthermore, the carbon cloth-riboflavin enriched various major methanogenic pathways and activated a large number of enzymes associated with DIET. Riboflavin's presence altered the microbial communities and the abundance of functional genes relate to DIET, ultimately leading to a better performance of anaerobic digestion for cow dung.

Granular activated carbon enhances volatile fatty acid production in the anaerobic fermentation of garden wastes

Garden waste, one type of lignocellulosic biomass, holds significant potential for the production of volatile fatty acids (VFAs) through anaerobic fermentation. However, the hydrolysis efficiency of garden waste is limited by the inherent recalcitrance, which further influences VFA production. Granular activated carbon (GAC) could promote hydrolysis and acidogenesis efficiency during anaerobic fermentation. This study developed a strategy to use GAC to enhance the anaerobic fermentation of garden waste without any complex pretreatments and extra enzymes. The results showed that GAC addition could improve VFA production, especially acetate, and reach the maximum total VFA yield of 191.55 mg/g VSadded, which increased by 27.35% compared to the control group. The highest VFA/sCOD value of 70.01% was attained in the GAC-amended group, whereas the control group only reached 49.35%, indicating a better hydrolysis and acidogenesis capacity attributed to the addition of GAC. Microbial community results revealed that GAC addition promoted the enrichment of Caproiciproducens and Clostridium, which are crucial for anaerobic VFA production. In addition, only the GAC-amended group showed the presence of Sphaerochaeta and Oscillibacter genera, which are associated with electron transfer processes. Metagenomics analysis indicated that GAC addition improved the abundance of glycoside hydrolases (GHs) and key functional enzymes related to hydrolysis and acidogenesis. Furthermore, the assessment of major genera influencing functional genes in both groups indicated that Sphaerochaeta, Clostridium, and Caproicibacter were the primary contributors to upregulated genes. These findings underscored the significance of employing GAC to enhance the anaerobic fermentation of garden waste, offering a promising approach for sustainable biomass conversion and VFA production.

Medical students' academic satisfaction: Social cognitive factors matter

PURPOSE

Academic satisfaction (AS)-the extent to which people enjoy their role or experiences as medical students-has important implications for well-being and career development. This study explores the relationships between social cognitive factors and AS in a Chinese medical education context.

METHOD

The social cognitive model of academic satisfaction (SCMAS) was adopted as the theoretical framework. Within this model, AS is assumed to be related to social cognitive factors-environmental supports, outcome expectations, perceived goal progress and self-efficacy. Demographic variables, financial pressure, college entrance examination scores and social cognitive constructs in SCMAS were collected. To explore the relationships between medical students' social cognitive factors and AS, hierarchical multiple regression analyses were performed.

RESULTS

The final sampled data consisted of 127 042 medical students from 119 medical institutions. Demographic variables, financial pressure and college entrance examination scores were first entered in Model 1, explaining 4% of the variance in AS. Social cognitive factors were entered in Model 2, explaining an additional 39% of the variance. Medical students would report higher levels of AS when they (a) held strong confidence in their skills needed for success in studying medicine (β = 0.20, p < 0.05), (b) had optimistic beliefs about the outcome of studying medicine (β = 0.40, p < 0.05), (c) felt that they were making good progress in studying medicine (β = 0.06, p < 0.05) and (d) believed that they received adequate environmental support (β = 0.25, p < 0.05). The outcome expectations showed the strongest correlation with AS, and each 1-point increase was associated with 0.39 points on the AS score, controlling for all other factors in the model.

CONCLUSIONS

Social cognitive factors play an important role in medical students' AS. Intervention programmes or courses aiming to improve medical students' AS are advised to consider social cognitive factors.

The Relationship Between Self-Regulated Learning Competency and Clinical Reasoning Tendency in Medical Students

Self-regulated learning (SRL) is essential to professional learning and practice across disciplines. However, the literature provides limited insights into how medical educators could leverage the SRL framework to support trainees' strategic processes in clinical reasoning activities. In this study, we investigated the relationship between SRL competency and clinical reasoning tendency as 64 medical students diagnosed a virtual patient in a computer-simulated environment. We further examined whether students with different profiles of SRL competency and clinical reasoning tendency differed in their behavioral patterns and performance. The results suggested that SRL competency positively predicted clinical reasoning tendency. Enhancing medical students' SRL competency, especially their self-reflection skills, could increase the tendency toward relying on an analytic approach to clinical reasoning. Moreover, we identified two groups of students (i.e., analytic SRL learners, and non-analytic, low SRL learners) using K-means clustering analysis. The two groups of students differed in their behavioral patterns in clinical reasoning, as revealed by lag sequential analysis. Furthermore, analytic SRL learners ordered more relevant lab tests than non-analytic low SRL learners in clinical reasoning. This study has methodological and practical implications.

Student engagement and learning outcomes: an empirical study applying a four-dimensional framework

INTRODUCTION

This study applies Reeve's four-dimensional student engagement framework to a medical education context to elucidate the relationship between behavioral, emotional, cognitive, and agentic engagement and learning outcomes. Meanwhile, we categorize learning outcomes in knowledge and skills, and added taxonomies to the cognitive education objectives for the knowledge part, including memorization, comprehension, and application.

METHODS

We used the China Medical Student Survey to investigate student engagement, and combined it with the Clinical Medicine Proficiency Test for Medical Schools results as a standardized measurement of learning outcomes. We performed multivariate regression analyses to delve into the effectiveness of different types of student engagement. Moreover, we evaluated the moderating roles of gender and the National College Entrance Examination (NCEE) within the relationships between student engagement and learning outcomes.

RESULTS

We observed that emotional engagement is most effective in promoting learning outcomes in basic medical knowledge and basic clinical skills. Emotional engagement and cognitive engagement could effectively contribute to learning outcomes in all three aspects of basic medical knowledge. In contrast, behavioral and agentic engagement showed negative effects on learning outcomes. Besides, we found that the results of the NCEE played a positive moderating role.

CONCLUSION

This study provides robust evidence for the effectiveness of emotional engagement and cognitive engagement in promoting learning outcomes. Whereas behavioral and agentic engagement may not be good predictors of learning outcomes in macro-level general competence tests. We suggest a combined effort by students and institutions to promote student engagement and bridge the distance between general competency tests and daily learning activities.

[Clinicopathological features of olfactory carcinoma]

Objective: To investigate the clinicopathological features and differential diagnosis of olfactory carcinoma (OC). Methods: Twenty-one cases of sinonasal tumors, including those initially diagnosed as olfactory neuroblastoma (ONB) and those with uncertain diagnosis, were collected from the Department of Pathology, the First Affiliated Hospital of University of Science and Technology of China (Anhui Provincial Hospital) from January 2016 to August 2022, among which 3 cases were reclassified as OC. The clinicopathological features were investigated, and the remaining 18 cases were used as control. Results: Of the three OC patients, 2 were male and 1 was female, with an average age of 57 years ranging from 35 to 74 years. Microscopically, the tumor cells were arranged in solid, nested or lobulated patterns with occasional palisading around the solid nests. The stroma was highly vascular with focal neurofibrillary areas. There were prominent rosettes or pseudorosettes formation. The tumor cells were mainly ovoid to spindly with scant to moderate amount of cytoplasm, one or several small nucleoli, and fine chromatin content. Brisk mitotic figures were seen. In all 3 cases of OC, there were scanty atypical glands and some were ciliated. Immunohistochemically, at least one epithelial marker and neuroendocrine marker were diffusely expressed in the tumor. Some of the tumor cells were positive for p40 and p63, and the sustentacular cells showed the expression of S-100 protein. All cases tested were negative for NUT, CD99 and desmin, with intact expression of SMARCA4 (BRG1) and SMARCB1 (INI-1). Ki-67 proliferation index varied from 20% to 80%. Follow-up after 16-18 months showed no mortality with tumor recurrence from 1 patient after 16 months. Conclusion: OC is a rare sinonasal tumor with neuroepithelial differentiation, its histomorphology is diverse, and the combination of immunohistochemical markers is essential for appropriate diagnosis.

A multi-center cross-sectional study on identification of influencing factors of medical students' emotional engagement in China

BACKGROUND

Studies exploring influencing factors of emotional engagement among medical students are scarce. Thus, we aimed to identify influencing factors of medical students' emotional engagement.

METHODS

We carried out a multi-center cross-sectional study among 10,901 medical students from 11 universities in China. The Chinese version of Utrecht Work Engagement Scale-Student version (UWES-S) was used to evaluate emotional engagement level of medical students. The predictors related to engagement level were determined by the logistic regression analysis. Furthermore, we constructed a nomogram to predict emotional engagement level of medical students.

RESULTS

A total of 10,576 sample were included in this study. The mean emotional engagement score was 74.61(± 16.21). In the multivariate logistic regression model, we found that males showed higher engagement level compared with females [odds ratio (OR) (95% confidence interval (CI)): 1.263 (1.147, 1.392), P < 0.001]. Medical students from the second batches of medical universities had higher engagement level and from "Project 985" universities had lower engagement level compared with 211 project universities [OR (95%CI): 1.376 (1.093, 1.733), P = 0.007; OR (95%CI): 0.682 (0.535, 0.868), P = 0.002]. Medical students in grade 4 and grade 2 presented lower engagement level compared with in grade 1 [OR (95%CI): 0.860 (0.752, 0.983), P = 0.027; OR (95%CI): 0.861 (0.757, 0.980), P = 0.023]. Medical students lived in provincial capital cities had higher engagement level compared with in country [OR (95%CI): 1.176 (1.022, 1.354), P = 0.024]. Compared with eight-year emotional duration, medical students in other emotional duration (three-year and four-year) had lower engagement level [OR (95%CI): 0.762 (0.628, 0.924), P = 0.006]. Medical students' engagement level increased with increases of grade point average and interest in studying medicine. Medical students learned by converging style showed lower engagement level [OR (95%CI): 0.827 (0.722, 0.946), P = 0.006] compared with accommodating style. The model showed good discriminative ability (area under curve = 0.778), calibrating ability and clinical utility.

CONCLUSIONS

We identified influencing factors of medical students' emotional engagement and developed a nomogram to predict medical students' emotional engagement level, providing reference and convenience for educators to assess and improve emotional engagement level of medical students. It is crucial for educators to pay more attention to emotional engagement of medical students and adopt effective strategies to improve their engagement level.

Induction of mitophagy via ROS-dependent pathway protects copper-induced hypothalamic nerve cell injury

Copper (Cu) is one of the essential trace elements in the body, but excessive amounts of Cu harm multiple organs and tissues such as liver, kidneys, testis, ovaries, and brain. However, the mechanism of hypothalamic neurotoxicity induced by Cu is still unknown. This study examined the relationship between reactive oxygen species (ROS) and mitophagy in mouse hypothalamus treated with high Cu. The results demonstrated that high levels of copper sulfate (CuSO4) could cause histopathological and neuronal changes in the mouse hypothalamus, produce a large amount of ROS, induce mitophagy, and lead to an imbalance of mitochondrial fusion/fission. The main manifestations are an increase in the expression levels of LC3-II/LC3-I, p62, DRP1, and FIS1, and a decrease in the expression levels of MFN1 and MFN2. Cu can induce mitophagy also was confirmed by LC3 co-localization with TOMM20 (mitochondrial marker). Next, the effect of oxidative stress on CuSO4-induced mitophagy was demonstrated. The results showed that ROS inhibitor N-acetylcysteine (NAC) diminished CuSO4-induced mitophagy and reversed the disturbance of mitochondrial dynamics. Additionally, a study was carried out to evaluate the role of mitophagy in CuSO4-induced hypothalamic injury. The inhibition of mitophagy using mitophagy inhibitor (Mdivi-1) decreased cell viability and promoted CuSO4-inhibited mitochondrial fusion. The aforementioned results suggested that CuSO4 induced mitophagy via oxidative stress in N38 cells and mouse hypothalamus, and that the activation of mitophagy might generate protective mechanisms by alleviating Cu-induced mitochondrial dynamics disorder. This study provided a novel approach and theoretical basis for studying and preventing Cu neurotoxicity.

The impact of student engagement on satisfaction with medical education in china: a supplementary perspective

As one of the indicators reflecting student well-being in medical education practice, student satisfaction is no doubt an important topic. Instead of exploring student satisfaction from the perspectives of education quality and organizational factors, this study focused on student engagement to explore the impact of it on student satisfaction with medical education in China. Student engagement refers to students' actions, efforts and persistence, indicating both time and energy students invested in educationally purposeful activities, especially academic activities. The data used in this study came from the first national survey of clinical undergraduates-the China Medical Student Survey-in which 10,062 clinical medical undergraduates in 33 medical schools participated. We developed a model of medical student engagement and satisfaction and utilized descriptive statistics, ordered logit regression, and path analysis to describe the relationship between medical student engagement and satisfaction. In this study, student engagement was categorized into behavioral, emotional and cognitive dimensions. The findings showed that medical student satisfaction was relatively low and was significantly affected by student satisfaction, especially the behavioral engagement in clinical rotations and professional identity of emotional engagement. These findings could put a supplementary perspective on improving student satisfaction through student engagement, and offer notable implications for future research and practice.

Megf10-related engulfment of excitatory postsynapses by astrocytes following severe brain injury

AIMS

To investigate astrocyte-related phagocytosis of synapses in the ipsilateral hippocampus after traumatic brain injury (TBI).

METHODS

We performed controlled cortical impact to simulate TBI in mice. Seven days postinjury, we performed cognitive tests, synapse quantification, and examination of astrocytic phagocytosis in association with Megf10 expression.

RESULTS

During the subacute stage post-TBI, we found a reduction in excitatory postsynaptic materials in the ipsilateral hippocampus, which was consistent with poor performance in the cognitive test. The transcriptome data suggested that robust phagocytosis was responsible for this process. Coincidently, we identified phagocytic astrocytes containing secondary lysosomes that were wrapped around the synapses in the ipsilateral hippocampus. Moreover, a significant increase in the co-location of GFAP and PSD-95 in the CA1 region suggested astrocytic engulfment of excitatory postsynaptic proteins. After examining the reported phagocytic pathways, we found that both the transcription level and protein expression of Megf10 were elevated. Co-immunofluorescence of GFAP and Megf10 demonstrated that the expression of Megf10 was spatially upregulated in astrocytes, exclusively in the CA1 region, and was related to the astrocytic engulfment of PSD-95.

CONCLUSION

Our study elaborated that the Megf10-related astrocytic engulfment of PSD-95 in the CA1 region of the ipsilateral hippocampus aggravated cognitive dysfunction following severe TBI.

Effects of the Education and Training Programme for Excellent Physicians in China on medical students' academic performance: a cross-sectional study

OBJECTIVES

To evaluate the effect of the Education and Training Programme for Excellent Physicians in China on medical students' academic performance.

DESIGN

This study is a secondary analysis of data from a cross-sectional survey of China Medical Student Survey (CMSS, 2021) and administrative data of the first-stage Medical Licensing Examination-the Standardised Competence Test for Clinical Medicine Undergraduates (the Test, 2021). CMSS used a stratified sampling process, with all undergraduate clinical medicine students participating voluntarily.

SETTING

This programme is implemented at the class level within reformed medical schools, targeting undergraduate students in 5-year clinical medicine in China. The reformed medical schools run pilot classes and traditional classes simultaneously. The analytic sample was a total of 12 243 observations from pilot and traditional classes in 34 medical schools which implemented the reform across 19 provinces in China.

METHODS

This study applied the propensity score matching method to estimate the effect of the reform by comparing the scores of the Test between pilot and traditional classes within the same medical schools. We further explored the potential mechanisms driving the effect from two facets of the Test: medical knowledge modules and cognitive levels.

RESULTS

Pilot classes outperformed traditional classes by 0.104 SD on the Test (95% CI 0.037 to 0.171). Improvements were seen in basic medicine and clinical medicine modules (0.109 and 0.101 SD, respectively) and cognitive levels of memorisation and application (0.116 and 0.111 SD, respectively).

CONCLUSION

These results suggest that the reform had a significant positive impact on medical students' academic performance. Based on the components of this reform and the potential mechanism analysis of the two facets, this study indicates that curriculum reform in integrated learning and teaching methods reform in the adoption of problem-based learning may have been the possible drivers of this positive impact.

Short-Wavelength Infrared Organic Light-Emitting Diodes from A-D-A'-D-A Type Small Molecules with Emission beyond 1100 nm

Short-wavelength infrared (SWIR) organic light-emitting diodes (OLEDs) have attracted great interest due to their potential applications in biological imaging, infrared lighting, optical communication, environmental monitoring, and surveillance. Due to an intrinsic limitation posed by the energy-gap law, achieving high-brightness in SWIR OLEDs remains a challenge. Herein, the study reports the use of novel A-D-A'-D-A type small molecules NTQ and BTQ for high-performance SWIR OLEDs. Benefiting from multiple D-A effect in conjugated skeleton, the small molecules NTQ and BTQ exhibit narrow optical gaps of 1.23 and 1.13 eV, respectively. SWIR electroluminescence (EL) emission from OLEDs based on NTQ and BTQ is achieved, with emission peaks at 1140 and 1175 nm, respectively. Not only owing to a negligible efficiency roll-off across the full range of applied current density but also the ability to afford a high operation current density of 5200 mA cm-2 , the resultant SWIR OLEDs based on NTQ exhibit a maximal radiant exitance of =1.12 mW cm-2 . Furthermore, the NTQ-based OLEDs also possess sub-gap turn-on voltage of 0.85 V, which is close to the physical limits derived from the generalized Kirchhoff and Planck equation. This work demonstrates that A-D-A'-D-A type small molecules offer significant promise for NIR/SWIR emitting material innovations.

A Potential Polycarbonyl Polyimide as Anode Material for Lithium-Ion Batteries

Organic polymers have been considered reliable candidates for lithium storage due to their high capacity and lack of volume expansion. Compared with other organic polymers, polyimide has become a very promising electrode material for lithium-ion batteries (LIBs) because of its easy synthesis, customizable structure and structural stability. A large number of studies have confirmed that the benzene ring structure of polyimide has strong lithium storage capacity as an anode material. Hence, we designed and synthesized polyimide organic polymer (PBPAQ) for the first time. The unique spherical flower structure of this material enhances the interaction between the electrode material and the electrolyte by increasing the contact area. The PBPAQ anode has a specific discharge capacity of 738 mAh g-1 after 100 cycles at 0.1 A g-1 . The excellent lithium storage performance of this material laid a foundation for the research of the anode of LIBs in the future.

SARS-Cov-2 Spike-S1 Antigen Test Strip with High Sensitivity Endowed by High-Affinity Antibodies and Brightly Fluorescent QDs/Silica Nanospheres

The extensive research into developing novel strategies for detecting respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens in clinical specimens, especially the sensitive point-of-care testing method, is still urgently needed to reach rapid screening of viral infections. Herein, a new lateral flow immunoassay (LFIA) platform was reported for the detection of SARS-CoV-2 spike-S1 protein antigens, in which four sensitive and specific SARS-CoV-2 mouse monoclonal antibodies (MmAbs) were tailored by using quantum dot (QD)-loaded dendritic mesoporous silica nanoparticles modified further for achieving the -COOH group surface coating (named Q/S-COOH nanospheres). Importantly, compact QD adsorption was achieved in mesoporous channels of silica nanoparticles on account of highly accessible central-radial pores and electrostatic interactions, leading to significant signal amplification. As such, a limit of detection for SARS-CoV-2 spike-S1 testing was found to be 0.03 ng/mL, which is lower compared with those of AuNPs-LFIA (traditional colloidal gold nanoparticles, Au NPs) and enzyme-linked immunosorbent assay methods. These results show that optimizing the affinity of antibody and the intensity of fluorescent nanospheres simultaneously is of great significance to improve the sensitivity of LFIA.

The effect of an information intervention on the career commitment of medical students: evidence from a randomized experiment

Introduction

The needs-based shortage of healthcare workers is severe worldwide and it would be exacerbated if many medical students switch to other careers after graduation. Maintaining and improving the career commitment of medical students, which could be a feasible, effective, and scalable way to reduce the attrition rate, is essential in medical education. We designed a randomized experiment to test whether an information intervention based on role modeling could enhance medical students' career commitment.

Methods

In the randomized experiment, the sample (N = 36,482) was divided into the treatment group (N = 18,070) and the control group (N = 18,412). The intervention information consisted of image-text messages on Zhong Nanshan, who is an inspiring role model for he went to the frontline of COVID-19 in the most critical circumstances and received praise and affirmation from the public. Α difference-in-differences model was employed to identify the effect of the information intervention. Heterogeneous treatment effects were identified using sub-sample analyses.

Results

The results showed that the information intervention statistically significantly reduced medical students' dropout intention by 2.7 percentage points (95% CI: -0.037 to -0.016, t = -4.95, p < 0.001), equivalent to 14.6% of the control group mean. This estimate indicates that the information intervention could significantly increase the career commitment of medical students. Finally, male and senior students were influenced more than their female and junior counterparts, which can be explained by their relatively high dropout intention.

Conclusion

Role model-based information intervention improves the career commitment of medical students. The underlying behavioral model is that, when students use a role model as their reference point, they consider dropout as a substantial welfare loss. Role modeling is an effective way to improve the career commitment of medical students, especially for males and senior students.

Unraveling the Role of Non-Fullerene Acceptor with High Dielectric Constant in Organic Solar Cells

Increasing the relative dielectric constant is a constant pursuit of organic semiconductors, but it often leads to multiple changes in device characteristics, hindering the establishment of a reliable relationship between dielectric constant and photovoltaic performance. Herein, a new non-fullerene acceptor named BTP-OE is reported by replacing the branched alkyl chains on Y6-BO with branched oligoethylene oxide chains. This replacement successfully increases the relative dielectric constant from 3.28 to 4.62. To surprise, BTP-OE offers consistently lower device performance relative to Y6-BO in organic solar cells (16.27% vs 17.44%) due to the losses in open-circuit voltage and fill factor. Further investigations unravel that BTP-OE has resulted in reduced electron mobility, increased trap density, enhanced first order recombination, and enlarged energetic disorder. These results demonstrate the complex relationship between dielectric constant and device performance, which provide valuable implications for the development of organic semiconductors with high dielectric constant for photovoltaic application.

Mastering morphology of non-fullerene acceptors towards long-term stable organic solar cells

Despite the rapid progress of organic solar cells based on non-fullerene acceptors, simultaneously achieving high power conversion efficiency and long-term stability for commercialization requires sustainable research effort. Here, we demonstrate stable devices by integrating a wide bandgap electron-donating polymer (namely PTzBI-dF) and two acceptors (namely L8BO and Y6) that feature similar structures yet different thermal and morphological properties. The organic solar cell based on PTzBI-dF:L8BO:Y6 could achieve a promising efficiency of 18.26% in the conventional device structure. In the inverted structure, excellent long-term thermal stability over 1400 h under 85 °C continuous heating is obtained. The improved performance can be ascribed to suppressed charge recombination along with appropriate charge transport. We find that the morphological features in terms of crystalline coherence length of fresh and aged films can be gradually regulated by the weight ratio of L8BO:Y6. Additionally, the occurrence of melting point decrease and reduced enthalpy in PTzBI-dF:L8BO:Y6 films could prohibit the amorphous phase to cluster, and consequently overcome the energetic traps accumulation aroused by thermal stress, which is a critical issue in high efficiency non-fullerene acceptors-based devices. This work provides insight into understanding non-fullerene acceptors-based organic solar cells for improved efficiency and stability.

Saddle-Shaped Third Component with Out-of-Plane Electrostatic Dipole for Realizing High-Performance Photovoltaic Donor Terpolymers

Terpolymer fabrication is an effective methodology for molecular engineering and generating high-performance organic photovoltaic materials to construct highly efficient polymer solar cells. Modification of the polymer PM6 by incorporating a third component resulting in the formation of a ternary copolymer is reported to outperform PM6 in achieving enhanced device performances. However, one of the major challenges in constructing high-performance terpolymers is to counter the molecular disorder caused by the backbone entropy induced by the third moiety. In this work, double B←N bridged bipyridine (BNBP) is used as the third component, which possesses a strong out-of-plane electrostatic dipole owing to the saddle-shaped B←N fused ring structure. The out-of-plane dipole moment introduced in the modified PM6 terpolymer can be used as a means for tuning and optimizing the nanostructures of the blended films. The prepared PM6-BNBP-4 blend polymer with 4% of the benzodithiophene dione monomers replaced by BNBP results in excellent power conversion efficiency of 19.13%. This work demonstrates that the out-of-plane electrostatic dipole moment in saddle-shaped molecules is valuable for achieving high-performance organic photovoltaic donor materials.

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.

Design and evaluation of a simulated wound management course for postgraduate year one surgery residents

Background

It is vital to cover wound management knowledge and operations in the early stages of resident training. With this in mind, a simulated wound management course for postgraduate year one surgery residents (PGY1s) was designed and its effectiveness was evaluated.

Methods

A retrospective quasi-experimental method was used. PGY1s in 2014 constituted the control group, and PGY1s in 2015 and 2016 constituted the intervention group. The course given to the control group comprised didactic teaching followed by deliberate practice plus immediate personalized feedback. The newly designed course given to the intervention group was reconstructed and disassembled into four components according to the simulation-based mastery learning model, which were baseline test, interactive learning, basic skills practice, and reflective learning. The same performance assessments were used in the control and intervention group, including process measurement and outcome measurement.

Results

The process measurement showed that the intervention group’s scores were significantly higher in the “dissociation of subcutaneous tissue” and “quality of suturing and knots”. The outcome measurement showed that the accuracy of debridement was greatly improved and both key and total suture numbers were significantly higher in the intervention group.

Conclusions

Simulation-based mastery learning was incorporated into our proposed course framework, promoting the learning outcome of PGY1s. It has the potential to be adapted for other surgical training sites for residents in China.