Thermal-tagging photoacoustic remote sensing flowmetry.

Ultrasound coupling is one of the critical challenges for traditional photoacoustic (or optoacoustic) microscopy (PAM) techniques transferred to the clinical examination of chronic wounds and open tissues. A promising alternative potential solution for breaking the limitation of ultrasound coupling in PAM is photoacoustic remote sensing (PARS), which implements all-optical non-interferometric photoacoustic measurements. Functional imaging of PARS microscopy was demonstrated from the aspects of histopathology and oxygen metabolism, while its performance in hemodynamic quantification remains unexplored. In this Letter, we present an all-optical thermal-tagging flowmetry approach for PARS microscopy and demonstrate it with comprehensive mathematical modeling and ex vivo and in vivo experimental validations. Experimental results demonstrated that the detectable range of the blood flow rate was from 0 to 12 mm/s with a high accuracy (measurement error:±1.2%) at 10-kHz laser pulse repetition rate. The proposed all-optical thermal-tagging flowmetry offers an effective alternative approach for PARS microscopy realizing non-contact dye-free hemodynamic imaging.

Self-injury and suicidal ideation among Chinese adolescents involved in different subtypes of aggression: The role of gender.

BACKGROUND: Although aggression associated self-injury and suicidal ideation, but the specific impact of different subtypes of aggression is unclear. Therefore, the current study aims to quantify the associations between five subtypes of aggression, self-injury, and suicidal ideation in Chinese adolescents. METHOD: A total of 18,532 students were recruited in grades 7 to 12 using a stratified cluster sampling across five representative provinces in China. The Functional Assessment of Self-Mutilation (CH-FASM) and Buss and Warren's Aggression Questionnaire (BWAQ) assess self-injury and aggression, respectively. RESULTS: During the last year, the proportion of self-injury, suicidal ideation, and self-injury plus suicidal ideation (SSI) were 13.4 %, 10.0 %, 12.4 %, respectively. Multivariate logistic regression indicated that hostility was associated with self-injury-only (OR = 1.033, 95 % CI = 1.021-1.044), suicidal ideation-only (OR = 1.075, 95 % CI = 1.061-1.088), and SSI (OR = 1.100, 95 % CI = 1.087-1.114) (all P < 0.001) across five subtypes of aggression. In gender stratification, physical aggression was risk factor for self-injury-only, suicidal ideation-only, and SSI (OR = 1.028, 95 % CI = 1.018-1.037, P < 0.001) in females. While anger was association with self-injury-only and suicidal ideation-only in males (P < 0.05). LIMITATIONS: This study was a cross-sectional design and self-reported questionnaire. CONCLUSION: Hostility is a strong predictor of self-injury and suicidal ideation across five subtypes of aggression. There are gender differences in relationships. Prevention programs for adolescents' self-injury and suicidal ideation should consider different subtypes of aggression and gender differences.

In vitro anti-Helicobacter pylori activity and the underlining mechanism of an empirical herbal formula - Hezi Qingyou.

Background: Helicobacter pylori (H. pylori) is thought to primarily colonize the human stomach and lead to various gastrointestinal disorders, such as gastritis and gastric cancer. Currently, main eradication treatment is triple or quadruple therapy centered on antibiotics. Due to antibiotic resistance, the eradication rate of H. pylori is decreasing gradually. Therefore, searching for anti-H. pylori drugs from herbal sources has become a strategy for the treatment. Our team proposed a Hezi Qingyou Formula (HZQYF), composed of Chebulae Fructus, Ficus hirta Vahl and Cloves, and studied its anti-H. pylori activity and mechanism. Methods: Chemical components of HZQYF were studied using UHPLC-MS/MS and HPLC. Broth microdilution method and agar dilution method were used to evaluate HZQYF's antibacterial activity. The effects of HZQYF on expression of adhesion genes (alpA, alpB, babA), urease genes (ureE, ureF), and flagellar genes (flaA, flaB) were explored using Reverse Transcription-quantitative Polymerase Chain Reaction (RT-qPCR) technology. Effects on morphology and permeability of the extracellular membrane were studied using scanning electron microscopy (SEM) and N-phenylnaphthalen-1-amine (NPN) uptake. Effect on urease activity was studied using a urease kinetics analysis in vitro. Immunofluorescence staining method was used to examine the effect on adhesion. Western blot was used to examine the effect on cagA protein. Results: Minimum inhibitory concentration (MIC) values of the formula against H. pylori clinical strains and standard strains were 80-160 µg/mL, and minimum bactericidal concentration (MBC) values were 160-320 µg/mL. The formula could down-regulate the expression of adhesion genes (alpA, alpB, babA), urease genes (ureE, ureF) and flagellar genes (flaA, flaB), change the morphology of H. pylori, increase its extracellular membrane permeability, and decrease its urease activity. Conclusion: Present studies confirmed that HZQYF had promising in vitro anti-H. pylori activities and demonstrated its possible mechanism of action by down-regulating the bacterial adhesion, urease, and flagellar gene expression, which provided scientific bases for further clinical investigations.

1,3,6-Trigalloylglucose: A Novel Potent Anti-Helicobacter pylori Adhesion Agent Derived from Aqueous Extracts of Terminalia chebula Retz.

1,3,6-Trigalloylglucose is a natural compound that can be extracted from the aqueous extracts of ripe fruit of Terminalia chebula Retz, commonly known as "Haritaki". The potential anti-Helicobacter pylori (HP) activity of this compound has not been extensively studied or confirmed in scientific research. This compound was isolated using a semi-preparative liquid chromatography (LC) system and identified through Ultra-high-performance liquid chromatography-MS/MS (UPLC-MS/MS) and Nuclear Magnetic Resonance (NMR). Its role was evaluated using Minimum inhibitory concentration (MIC) assay and minimum bactericidal concentration (MBC) assay, scanning electron microscope (SEM), inhibiting kinetics curves, urea fast test, Cell Counting Kit-8 (CCK-8) assay, Western blot, and Griess Reagent System. Results showed that this compound effectively inhibits the growth of HP strain ATCC 700392, damages the HP structure, and suppresses the Cytotoxin-associated gene A (Cag A) protein, a crucial factor in HP infection. Importantly, it exhibits selective antimicrobial activity without impacting normal epithelial cells GES-1. In vitro studies have revealed that 1,3,6-Trigalloylglucose acts as an anti-adhesive agent, disrupting the adhesion of HP to host cells, a critical step in HP infection. These findings underscore the potential of 1,3,6-Trigalloylglucose as a targeted therapeutic agent against HP infections.

High-Performance PMN-PT Single-Crystal-Based 1-3 Composite Transducer Integrated with a Biopsy Needle.

To address the need for high-resolution imaging in lung nodule detection and overcome the limitations of the shallow imaging depth associated with high-frequency ultrasound and the complex structure of lung tissue, we successfully integrated 50 MHz ultrasound transducers with 18-gauge biopsy needles. Featuring a miniaturized size of 0.6 × 0.5 × 0.5 mm3, the 50 MHz micromachined 1-3 composite transducer was tested to perform mechanical scanning of a nodule within a lung-tissue-mimicking phantom in vitro. The high-frequency transducer demonstrated the ability to achieve imaging with an axial resolution of 30 µm for measuring nodule edges. Moreover, the integrated biopsy needle prototype exhibited high accuracy (1.74% discrepancy) in estimating nodule area compared to actual dimensions in vitro. These results underscore the promising potential of biopsy-needle-integrated transducers in enhancing the accuracy of endoscopic ultrasound-guided fine needle aspiration biopsy (EUS-FNA) for clinical applications.

The symbiont Wolbachia alleviates pesticide susceptibility in the two-spotted spider mite Tetranychus urticae through enhanced host detoxification pathways.

The two-spotted spider mite (Tetranychus urticae) is one of the most well-known pesticide-resistant agricultural pests, with resistance often attributed to changes such as target-site mutations and detoxification activation. Recent studies show that pesticide resistance can also be influenced by symbionts, but their involvement in this process in spider mites remains uncertain. Here, we found that infection with Wolbachia, a well-known bacterial reproductive manipulator, significantly increased mite survival after exposure to the insecticides abamectin, cyflumetofen, and pyridaben. Wolbachia-infected (WI) mites showed higher expression of detoxification genes such as P450, glutathione-S-transferase (GST), ABC transporters, and carboxyl/cholinesterases. RNA interference experiments confirmed the role of the two above-mentioned detoxification genes, TuCYP392D2 and TuGSTd05, in pesticide resistance. Increased GST activities were also observed in abamectin-treated WI mites. In addition, when wild populations were treated with abamectin, WI mites generally showed better survival than uninfected mites. However, genetically homogeneous mites with different Wolbachia strains showed similar survival. Finally, abamectin treatment increased Wolbachia abundance without altering the mite's bacterial community. This finding highlights the role of Wolbachia in orchestrating pesticide resistance by modulating host detoxification. By unraveling the intricate interplay between symbionts and pesticide resistance, our study lays the groundwork for pioneering strategies to combat agricultural pests.

Unraveling the complex roles of macrophages in obese adipose tissue: an overview.

Macrophages, a heterogeneous population of innate immune cells, exhibit remarkable plasticity and play pivotal roles in coordinating immune responses and maintaining tissue homeostasis within the context of metabolic diseases. The activation of inflammatory macrophages in obese adipose tissue leads to detrimental effects, inducing insulin resistance through increased inflammation, impaired thermogenesis, and adipose tissue fibrosis. Meanwhile, adipose tissue macrophages also play a beneficial role in maintaining adipose tissue homeostasis by regulating angiogenesis, facilitating the clearance of dead adipocytes, and promoting mitochondrial transfer. Exploring the heterogeneity of macrophages in obese adipose tissue is crucial for unraveling the pathogenesis of obesity and holds significant potential for targeted therapeutic interventions. Recently, the dual effects and some potential regulatory mechanisms of macrophages in adipose tissue have been elucidated using single-cell technology. In this review, we present a comprehensive overview of the intricate activation mechanisms and diverse functions of macrophages in adipose tissue during obesity, as well as explore the potential of drug delivery systems targeting macrophages, aiming to enhance the understanding of current regulatory mechanisms that may be potentially targeted for treating obesity or metabolic diseases.

Switchable Two-Dimensional AND and Exclusive OR Operation Based on Dual-Wavelength Metasurfaces.

Logic operation serves as the foundation and core element of computing networks; it will bring huge vitality to advanced information processing with its adaptation in the optical domain. As fundamental logic operations, AND and exclusive OR (XOR) operations serve a multitude of purposes, such as their ability to cooperate in enabling image processing and interpretation. Here, we propose and experimentally demonstrate a wavelength multiplexed AND and XOR function based on metasurfaces. By combining two cosine gratings with distinct frequencies and an initial phase difference of π/2, we extract the similarities and differences between two input images simultaneously by illuminating them with 445 and 633 nm wavelengths. Additionally, we explore its potential in information encryption, where overall security is enhanced by distributing distinct parts of initial information and encoded keys to different receivers. This design possesses the benefits of convenient mode switching and high-quality imaging, facilitating advanced applications in pattern recognition, machine vision, medical diagnosis, etc.

Mobile phone addiction and suicide behaviors among Chinese adolescents: The mediation of poor sleep quality.

Background and aims: Mobile phone addiction (MPA) is emerging among adolescents, especially during the COVID-19 pandemic. Nevertheless, there is a dearth of knowledge regarding the correlation between MPA and suicide behaviors and its mechanism. The objective of the current study is exploring the direct effect of MPA on suicide behaviors and the indirect effect through poor sleep quality. Methods: A total of 18,900 Chinese adolescents aged 12 to 18 were recruited via a multi-stage cluster sampling method. Results: The prevalence of MPA and poor sleep quality was 26.2 and 23.1%, respectively. During the past year, 24.4% participants were involved in suicide behaviors. Specifically, suicide ideators, suicide planners, and suicide attempters were 10.7, 8.4, and 5.3%, respectively. Particularly, rural females had the highest prevalence of suicide behaviors, MPA, and poor sleep quality. Logistic regression analysis showed that MPA was significantly associated with suicide ideators (OR = 1.22, 95% CI: 1.09-1.37, p < 0.001) and planners (OR = 1.18, 95% CI: 1.04-1.34, p < 0.05), but not for suicide attempters (p > 0.05). Structural equation modelling demonstrated that MPA had direct effect on suicide behaviors (ß = 0.145, 95% CI = 0.127-0.160), and poor sleep quality partially mediated the relationship (the mediating ratio was 46.7%). The mediating ratio of poor sleep quality was the highest in urban males. Conclusions: MPA has both direct and indirect effects on suicide behaviors. For suicide prevention, limited mobile phone use and improvement sleep quality may be practical for adolescents. Additionally, more efforts of intervention could give priority to rural girls.

Specific and cumulative effects of childhood maltreatment on nonsuicidal self-injury in Chinese adolescents: The moderating effect of sleep disturbance.

BACKGROUND: Numerous studies have examined the relationship between childhood maltreatment (CM) and nonsuicidal self-injury (NSSI). However, few studies have explored both the specific and cumulative effects of CM on NSSI. Additionally, the impact of sleep disturbance on the association between CM and NSSI remains unclear. OBJECTIVES: To comprehensively explore the effects of CM on NSSI, and to determine whether these effects are moderated by sleep disturbance. PARTICIPANTS AND SETTING: A retrospective study was conducted in April 2021 among a representative sample of 21,340 students aged 11-20 years in China. METHODS: All participants completed questionnaires assessing CM, sleep disturbance, and NSSI. Adjusted multivariate logistic regression models were utilized to evaluate the associations between CM and NSSI, as well as the impact of sleep disturbance. RESULTS: The findings revealed that 13.0 % of adolescents reported occasional NSSI, while 25.2 % reported repetitive NSSI. Except for sexual abuse, all subtypes of CM were significantly associated with increased odds of both occasional and repetitive NSSI. A significant dose-response relationship was observed between cumulative CM and repetitive NSSI. Stratification analyses by sleep disturbance indicated that adolescents reporting sleep disturbance had a higher risk of developing repetitive NSSI, irrespective of the type of CM experienced. Furthermore, a dose-response relationship was identified between cumulative CM and repetitive NSSI among adolescents reporting sleep disturbance. CONCLUSION: This study demonstrated that CM increases the risk of NSSI among Chinese adolescents, and sleep disturbance plays a moderating role. Interventions targeting sleep disturbance may hold significance in reducing NSSI.

Evolving from Didactic to Dialogic: How to Improve Faculty Development and Support Faculty Developers by Using Action Research.

Problem: Since competency-based medical education has gained widespread acceptance to guide curricular reforms, faculty development has been regarded as an indispensable element to make these programs successful. Faculty developers have striven to design and deliver myriad of programs or workshops to better prepare faculty members for fulfilling their teaching roles. However, how faculty developers can improve workshop delivery by researching their teaching practices remains underexplored. Intervention: Action research aims to understand real world practices and advocates for formulation of doable plans through cycles of investigations, and ultimately contributes to claims of knowledge and a progression toward the goal of practice improvement. This methodology aligns with the aim of this study to understand how I could improve a faculty development workshop by researching my teaching practices. Context: In 2016, we conducted four cycles of action research in the context of mini-Clinical Evaluation Exercise (mini-CEX) workshops within a faculty development program aiming for developing teaching and assessment competence in faculty members. We collected multiple sources of qualitative data for thematic analysis, including my reflective journal, field notes taken by a researcher-observer, and post-workshop written reflection and feedback in portfolio from fourteen workshop attendees aiming to develop faculty teaching and assessment competence. Impact: By doing action research, I scrutinized each step as an opportunity for change, enacted adaptive practice and reflection on my teaching practices, and formulated action plans to transform a workshop design through each cycle. In so doing, my workshop evolved from didactic to dialogic with continuous improvement on enhanced engagement, focused discussion and participant empowerment through a collaborative inquiry into feedback practice. Moreover, these processes of action research also supported my growth as a faculty developer. Lessons Learned: The systematic approach of action research serves as a vehicle to enable faculty developers to investigate individual teaching practices as a self-reflective inquiry, to examine, rectify, and transform processes of program delivery, and ultimately introduce themselves as agents for change and improvement.

Novel adaptive loss weighted transfer network for partial domain fault diagnosis.

Mechanical fault transfer diagnosis has been confirmed as a feasible approach for tackling intelligent diagnosis with incomplete fault information and scarce labeled data on the basis of big data through the transfer of diagnostic knowledge from one or more conditions to any other condition. However, existing research has developed a hypothesis, i.e., the target domain shares an identical label space with the source domain, making it unfeasible to address the practical issue that the target domain label space is a subset of the source domain label space, resulting in low transfer diagnosis accuracy. To address this issue, a novel unsupervised intelligent diagnosis approach named double classifiers-dependent transfer diagnosis network is developed. In this approach, the label distribution weights are generated through the probability output of the classifier of source domain label space to target domain samples, by which small weights are assigned to irrelevant source samples to avoid negative transfer in the global-local maximum mean discrepancies (GL-MMD). In addition, classifiers of the source domain label space and the shared label space are built separately to improve the reliability of label distribution weights and GL-MMD. By training the network in the shared label space, diagnostic knowledge in partial domain issues is effectively transferred. Two cases are implemented to verify the effectiveness of the developed approach. Compared with other transfer diagnosis approaches, the developed approach achieved better diagnostic performance.

Green fabrication of high-performance silver nanoparticles/reduced Ti3C2TxMXene nanocomposite catalyst for 4-nitrophenol reduction.

The outstanding electrical conductivity of transition metal carbides Ti3C2Tx(MXene) makes it as an excellent electron transfer medium for fabrication of efficient catalysts. However, the poor stability of MXene may restrict its application. Herein, a novel silver nanoparticles/reduced MXene nanocomposite (AgNPs/rMXene) catalyst was prepared by using L-arginine (L-Arg) as a green reducing agent. In the AgNPs/rMXene catalyst, the silver nanoparticles (AgNPs) and reduced MXene (rMXene) acted as catalytic active species and electron transfer medium, respectively. The composite catalyst exhibited superior catalytic activity in the conversion of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP), and the conversion frequency (TOF) was high up to 1109.4 h-1. Notably, the composite catalyst also showed high stability due to the reduction of L-Arg (i.e. the repair of defect groups on MXene surface). The conversion efficiency for 4-NP reduction by AgNPs/rMXene was high up to 90% after five recycles. This present study offers a simple and green approach for the design and development of efficient MXene-based catalysts.

A Backing-Layer-Shared Miniature Dual-Frequency Ultrasound Probe for Intravascular Ultrasound Imaging: In Vitro and Ex Vivo Validations.

Intravascular ultrasound (IVUS) imaging has been extensively utilized to visualize atherosclerotic coronary artery diseases and to guide coronary interventions. To receive ultrasound signals within the vessel wall safely and effectively, miniaturized ultrasound transducers that meet the strict size constraints and have a simple manufacturing procedure are highly demanded. In this work, the first known IVUS probe that employs a backing-layer-shared dual-frequency structure and a single coaxial cable is introduced, featuring a small thickness and easy interconnection procedure. The dual-frequency transducer is designed to have center frequencies of 30 MHz and 80 MHz, and both have an aperture size of 0.5 mm × 0.5 mm. The total thickness of the dual-frequency transducer is less than 700 µm. In vitro phantom imaging and ex vivo porcine coronary artery imaging experiments are conducted. The low-frequency transducer achieves spatial resolutions of 40 µm axially and 321 µm laterally, while the high-frequency transducer exhibits axial and lateral resolutions of 17 µm and 247 µm, respectively. A bandpass filter is utilized to separate the ultrasound images. Combining in vitro phantom imaging analysis with ex vivo imaging validation, a comprehensive demonstration of the promising application of the proposed miniature ultrasound probe is established.

Flexible Ultrasonic Transducers for Wearable Biomedical Applications: A Review on Advanced Materials, Structural Designs, and Future Prospects.

Due to the rapid developments in materials science and fabrication techniques, wearable devices have recently received increased attention for biomedical applications, particularly in medical ultrasound imaging, sensing, and therapy. Ultrasound is ubiquitous in biomedical applications because of its non-invasive nature, nonionic radiating, high precision, and real-time capabilities. While conventional ultrasound transducers are rigid and bulky, flexible transducers can be conformed to curved body areas for continuous sensing without restricting tissue movement or transducer shifting. This article comprehensively reviews the application of flexible ultrasound transducers in the field of biomedical imaging, sensing, and therapy. First, we review the background of flexible ultrasound transducers. Following that, we discuss advanced materials and fabrication techniques for flexible ultrasound transducers and their enabling technology status. Lastly, we highlight and summarize some promising preliminary data with recent applications of flexible ultrasound transducers in biomedical imaging, sensing, and therapy. We also provide technical barriers, challenges, and future perspectives for further research and development.

Sexual orientations in association between childhood maltreatment and depression among undergraduates in mainland of China.

BACKGROUND: There is growing evidence that sexual minorities including lesbian, gay, bisexual and questioning individuals (LGBQ) have significantly higher rates of childhood maltreatment than heterosexuals. However, few studies focused on the association between different type of childhood maltreatment and depression in LGBQs. METHODS: Cross-sectional study by random sampling was conducted among the undergraduates in mainland of China. A total of 1920 undergraduates from different majors and colleges completed self-report questionnaires to record depression, childhood maltreatment, sexual orientation and other related information. The associations were examined via a set of logistic regression analysis. RESULTS: Compared to the participants who had never experienced childhood maltreatment, the participants who reported emotional abuse (p < 0.001) and sexual abuse (p < 0.05) had higher odds of depression. The LGBQs have higher risk of being the victims of childhood maltreatment. The prevalence of depression was much higher in the LGBQ than that in the heterosexuals (33.9 % vs 16.1 %, χ2 = 43.627, p < 0.001). Compared to heterosexual adolescents, LGBQs had significantly higher odds of depression (p < 0.001). LIMITATIONS: Cross-sectional design, self-reported information, and unable to examine underlying protective factors. CONCLUSIONS: Emotional abuse, emotional neglect and sexual abuse have stronger association with LGBQ than other kind of childhood maltreatment. Emotional abuse and sexual abuse have stronger association with depression. Sexual abuse has stronger association with depression in LGBQs than heterosexuals. More attention to the mental health should be paid especially in LGBQs to reduce the risk of depression.

SIRT6 mediated histone H3K9ac deacetylation involves myocardial remodelling through regulating myocardial energy metabolism in TAC mice.

Pathological myocardial remodelling is the initial factor of chronic heart failure (CHF) and is induced by multiple factors. We previously demonstrated that histone acetylation is involved in CHF in transverse aortic constriction (TAC) mice, a model for pressure overload-induced heart failure. In this study, we investigated whether the histone deacetylase Sirtuin 6 (SIRT6), which mediates deacetylation of histone 3 acetylated at lysine 9 (H3K9ac), is involved pathological myocardial remodelling by regulating myocardial energy metabolism and explored the underlying mechanisms. We generated a TAC mouse model by partial thoracic aortic banding. TAC mice were injected with the SIRT6 agonist MDL-800 at a dose of 65 mg/kg for 8 weeks. At 4, 8 and 12 weeks after TAC, the level of H3K9ac increased gradually, while the expression of SIRT6 and vascular endothelial growth factor A (VEGFA) decreased gradually. MDL-800 reversed the effects of SIRT6 on H3K9ac in TAC mice and promoted the expression of VEGFA in the hearts of TAC mice. MDL-800 also attenuated mitochondria damage and improved mitochondrial respiratory function through upregulating SIRT6 in the hearts of TAC mice. These results revealed a novel mechanism in which SIRT6-mediated H3K9ac level is involved pathological myocardial remodelling in TAC mice through regulating myocardial energy metabolism. These findings may assist in the development of novel methods for preventing and treating pathological myocardial remodelling.

Striving to thrive or striving to survive: Professional identity constructions of medical trainees in clinical assessment activities.

CONTEXT: Assessment plays a key role in competence development and the shaping of future professionals. Despite its presumed positive impacts on learning, unintended consequences of assessment have drawn increasing attention in the literature. Considering professional identities and how these can be dynamically constructed through social interactions, as in assessment contexts, our study sought to understand how assessment influences the construction of professional identities in medical trainees. METHODS: Within social constructionism, we adopted a discursive, narrative approach to investigate the different positions trainees narrate for themselves and their assessors in clinical assessment contexts and the impact of these positions on their constructed identities. We purposively recruited 28 medical trainees (23 students and five postgraduate trainees), who took part in entry, follow-up and exit interviews of this study and submitted longitudinal audio/written diaries across nine-months of their training programs. Thematic framework and positioning analyses (focusing on how characters are linguistically positioned in narratives) were applied using an interdisciplinary teamwork approach. RESULTS: We identified two key narrative plotlines, striving to thrive and striving to survive, across trainees' assessment narratives from 60 interviews and 133 diaries. Elements of growth, development, and improvement were identified as trainees narrated striving to thrive in assessment. Neglect, oppression and perfunctory narratives were elaborated as trainees narrated striving to survive from assessment. Nine main character tropes adopted by trainees with six key assessor character tropes were identified. Bringing these together we present our analysis of two exemplary narratives with elaboration of their wider social implications. CONCLUSION: Adopting a discursive approach enabled us to better understand not only what identities are constructed by trainees in assessment contexts but also how they are constructed in relation to broader medical education discourses. The findings are informative for educators to reflect on, rectify and reconstruct assessment practices for better facilitating trainee identity construction.

The development and benefits of metformin in various diseases.

Metformin has been used for the treatment of type II diabetes mellitus for decades due to its safety, low cost, and outstanding hypoglycemic effect clinically. The mechanisms underlying these benefits are complex and still not fully understood. Inhibition of mitochondrial respiratory-chain complex I is the most described downstream mechanism of metformin, leading to reduced ATP production and activation of AMP-activated protein kinase (AMPK). Meanwhile, many novel targets of metformin have been gradually discovered. In recent years, multiple pre-clinical and clinical studies are committed to extend the indications of metformin in addition to diabetes. Herein, we summarized the benefits of metformin in four types of diseases, including metabolic associated diseases, cancer, aging and age-related diseases, neurological disorders. We comprehensively discussed the pharmacokinetic properties and the mechanisms of action, treatment strategies, the clinical application, the potential risk of metformin in various diseases. This review provides a brief summary of the benefits and concerns of metformin, aiming to interest scientists to consider and explore the common and specific mechanisms and guiding for the further research. Although there have been countless studies of metformin, longitudinal research in each field is still much warranted.