Effective online large-group teaching in health professions education

Jie Ming Nigel Fong,Li Ping Marianne Tsang,Nigel Choon Kiat Tan,Daniel Salcedo,Kevin Tan 한국의학교육학회 2022 Korean journal of medical education Vol.34 No.2

Online large-group teaching (OLGT), employed to reach a large group of learners in separate physical locations, allows asynchronous learning and facilitates social distancing. While online large-groups can be a powerful and resource-lean means of health professions education, it has challenges and potential pitfalls that may affect the learning process and outcomes. Through a sociomateriality framework, this article describes strategies for effective online large-group teaching in health professions education in three key strands. Firstly, to optimize learning, OLGT sessions should match learning needs with appropriate OLGT platforms, incorporate strategies to sustain learner attention, and accommodate learners of different abilities. Secondly, to develop a learning culture, OLGT must not only focus on cognitive aspects of learning but also build a community of practice, nurture digital professionalism and professional identity. Thirdly, we discuss the avoidance of pitfalls such as cognitive overload of both tutors and learners, technical issues and security risks, mitigating inequities in access to online learning, and the use of program evaluation to plan for sustained improvements. We conclude with a case vignette that discusses the challenges of OLGT and the application of the above strategies in a teaching scenario.

Damage monitoring of variable cross-section region in a column-drilled shaft assembly using smart aggregates

Jie Tan,Mahadi Masud,Xiaoming Qin,Cheng Yuan,Qingzhao Kong,Y.L.Mo 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.28 No.5

Pier column, as the most critical load-bearing member of bridge, can bear multiple loads including axial forces,shear forces, bending moments, etc. The varied cross section at the column interface and bearing platform or drilled shaft leads to harmful stress concentration that can potentially compromise the structural integrity. In order to improve the ductility of bridge structure, a pier column is often designed with a variable cross-section region to dissipate energy through plastic deformation. For better understanding the health condition of pier column in its service life, it is of great significance to obtain the damage severity information in the variable cross-section region. This study utilizes an active sensing method enabled by distributed Lead Zirconate Titanate (PZT)-based Smart Aggregate (SA) sensors to monitor the damage initiation and development near the bottom of a pier column. Crack damage in variable cross-section region functions as a stress relief that attenuates propagating stress wave energy between SA pairs. Both the numerical and experimental results show that the reduction ratio of the stress wave energy is consistent with the crack development, thus validating the reliability of the investigated approach. SA-based technology can be used as a potential tool to provide early warning of damage in variable cross-section region of bridge structures.

Comparison System Method for a class of Stochastic Systems with Variable-time Impulses

Jie Tan,Chuandong Li,Tingwen Huang 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.2

This paper studies the stability of stochastic impulsive systems with variable-time impulses. We consider the case that the trajectory of the stochastic system intersects each surface of discontinuity exactly once. Then we shall show that under the well-selected conditions the variable-time impulsive systems can be reduced to the fixed-time impulsive systems with impulse time window. By using comparison method, we obtain two theorems to determine the different impulsive time windows for stable and unstable stochastic dynamical systems, respectively. The effectiveness of the theoretical results are illustrated by two numerical examples.

Effect of Light with Different Wavelengths on Nostoc flagelliforme Cells in Liquid Culture

( Yu Jie Dai ),( Jing Li ),( Shu Mei Wei ),( Nan Chen ),( Yu Peng Xiao ),( Zhi Lei Tan ),( Shi Ru Jia ),( Nan Nan Yuan ),( Ning Tan ),( Yi Jie Song ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.4

The effects of lights with different wavelengths on the growth and the yield of extracellular polysaccharides of Nostoc flagelliforme cells were investigated in a liquid cultivation. N. flagelliforme cells were cultured for 16 days in 500 ml conical flasks containing BG11 culture medium under 27 μmol·m-2·s-1 of light intensity and 25oC on a rotary shaker (140 rpm). The chlorophyll a, phycocyanin, allophycocyanin, and phycoerythrin contents in N. flagelliforme cells under the lights of different wavelengths were also measured. It was found that the cell biomass and the yield of polysaccharide changed with different wavelengths of light. The biomass and the yield of extracellular polysaccharides under the red or violet light were higher than those under other light colors. Chlorophyll a, phycocyanin, and allophycocyanin are the main pigments in N. flagelliforme cells. The results showed that N. flagelliforme, like other cyanobacteria, has the ability of adjusting the contents and relative ratio of its pigments with the light quality. As a conclusion, N. flagelliforme cells favor red and violet lights and perform the complementary chromatic adaptation ability to acclimate to the changes of the light quality in the environment.

Global prevalence of depression and anxiety in patients with hepatocellular carcinoma: Systematic review and meta-analysis

Darren Jun Hao Tan,Sabrina Xin Zi Quek,Jie Ning Yong,Adithya Suresh,Kaiser Xuan Ming Koh,Wen Hui Lim,Jingxuan Quek,Ansel Tang,Caitlyn Tan,Benjamin Nah,Eunice Tan,Taisei Keitoku,Mark D. Muthiah,Nichola 대한간학회 2022 Clinical and Molecular Hepatology(대한간학회지) Vol.28 No.4

Background/Aims: Depression and anxiety are associated with poorer outcomes in patients with hepatocellular carcinoma (HCC). However, the prevalence of depression and anxiety in HCC are unclear. We aimed to establish the prevalence of depression and anxiety in patients with HCC. Methods: MEDLINE and Embase were searched and original articles reporting prevalence of anxiety or depression in patients with HCC were included. A generalized linear mixed model with Clopper-Pearson intervals was used to obtain the pooled prevalence of depression and anxiety in patients with HCC. Risk factors were analyzed via a fractional-logistic regression model. Results: Seventeen articles involving 64,247 patients with HCC were included. The pooled prevalence of depression and anxiety in patients with HCC was 24.04% (95% confidence interval [CI], 13.99–38.11%) and 22.20% (95% CI, 10.07–42.09%) respectively. Subgroup analysis determined that the prevalence of depression was lowest in studies where depression was diagnosed via clinician-administered scales (16.07%;95% CI, 4.42–44.20%) and highest in self-reported scales (30.03%; 95% CI, 17.19–47.01%). Depression in patients with HCC was lowest in the Americas (16.44%; 95% CI, 6.37–36.27%) and highest in South-East Asia (66.67%; 95% CI, 56.68–75.35%). Alcohol consumption, cirrhosis, and college education significantly increased risk of depression in patients with HCC. Conclusions: One in four patients with HCC have depression, while one in five have anxiety. Further studies are required to validate these findings, as seen from the wide CIs in certain subgroup analyses. Screening strategies for depression and anxiety should also be developed for patients with HCC.

An improved critical plane-energy multiaxial fatigue life prediction model considering shear mean stress

Jie Zhou,Zhengchao Tan,Linwei CaoLingze Meng,Yuexing Wang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.5

In the present research, the effects of normal mean stress acting on fatigue evolution are considered well in critical plane multiaxial models, whereas shear mean stress effects have rarely attracted attention. These models may result in nonconservative predictions under asymmetric loadings with substantial shear mean stress. Therefore, an improved critical energy model is introduced to solve multiaxial fatigue issues on the basis of the Fatemi-Socie model and the Walker model, which consider normal mean effect, shear mean stress effect, and additional hardening effect. Moreover, experimental data from GH4169, wrought Ti-6Al-4V, and TC4 are employed to validate the proposed model. Results show that the proposed model can reasonably predict fatigue life under various loadings, particularly for asymmetric loadings.

Synthesis and Experimental Implementation of DSP Based Backstepping Control of Positioning Systems

Jie Chang,Yaolong Tan 전력전자학회 2007 JOURNAL OF POWER ELECTRONICS Vol.7 No.1

Novel nonlinear backstepping control with integrated adaptive control function is developed for high-performance positioning control systems. The proposed schemes are synthesized by a systematic approach and implemented based on a modern low-cost DSP controller, TMS320C32. A baseline backstepping control scheme is derived first, and is then extended to include a nonlinear adaptive control against the system parameter changes and load variations. The backstepping control utilizes Lyapunov function to guarantee the convergence of the position tracking error. The final control algorithm is a convenient in the implementation of a practical 32-bit DSP controller. The new control system can achieve superior performance over the conventional nested PI controllers, with improved position tracking, control bandwidth, and robustness against external disturbances, which is demonstrated by experimental results.

Development of covalent inhibitors that can overcome resistance to first-generation FGFR kinase inhibitors

Tan, Li,Wang, Jun,Tanizaki, Junko,Huang, Zhifeng,Aref, Amir R.,Rusan, Maria,Zhu, Su-Jie,Zhang, Yiyun,Ercan, Dalia,Liao, Rachel G.,Capelletti, Marzia,Zhou, Wenjun,Hur, Wooyoung,Kim, NamDoo,Sim, Taebo,G National Academy of Sciences 2014 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.111 No.45

<P><B>Significance</B></P><P>Inhibitors of the FGF receptors (FGFRs) are currently under clinical investigation for the treatment of various cancers. All currently approved kinase inhibitors eventually are rendered useless by the emergence of drug-resistant tumors. We used structure-based drug design to develop the first, to our knowledge, selective, next-generation covalent FGFR inhibitors that can overcome the most common form of kinase inhibitor resistance, the mutation of the so-called “gatekeeper” residue located in the ATP-binding pocket. We also describe a novel kinase inhibitor design strategy that uses a single electrophile to target covalently cysteines that are located in different positions within the ATP-binding pocket. These results have important implications for the design of covalent FGFR inhibitors that can overcome clinical resistance.</P><P>The human FGF receptors (FGFRs) play critical roles in various human cancers, and several FGFR inhibitors are currently under clinical investigation. Resistance usually results from selection for mutant kinases that are impervious to the action of the drug or from up-regulation of compensatory signaling pathways. Preclinical studies have demonstrated that resistance to FGFR inhibitors can be acquired through mutations in the FGFR gatekeeper residue, as clinically observed for FGFR4 in embryonal rhabdomyosarcoma and neuroendocrine breast carcinomas. Here we report on the use of a structure-based drug design to develop two selective, next-generation covalent FGFR inhibitors, the FGFR irreversible inhibitors 2 (FIIN-2) and 3 (FIIN-3). To our knowledge, FIIN-2 and FIIN-3 are the first inhibitors that can potently inhibit the proliferation of cells dependent upon the gatekeeper mutants of FGFR1 or FGFR2, which confer resistance to first-generation clinical FGFR inhibitors such as NVP-BGJ398 and AZD4547. Because of the conformational flexibility of the reactive acrylamide substituent, FIIN-3 has the unprecedented ability to inhibit both the EGF receptor (EGFR) and FGFR covalently by targeting two distinct cysteine residues. We report the cocrystal structure of FGFR4 with FIIN-2, which unexpectedly exhibits a “DFG-out” covalent binding mode. The structural basis for dual FGFR and EGFR targeting by FIIN3 also is illustrated by crystal structures of FIIN-3 bound with FGFR4 V550L and EGFR L858R. These results have important implications for the design of covalent FGFR inhibitors that can overcome clinical resistance and provide the first example, to our knowledge, of a kinase inhibitor that covalently targets cysteines located in different positions within the ATP-binding pocket.</P>

Inhibition of ERK and Activation of p38 are Involved in Diallyl Disulfide Induced Apoptosis of Leukemia HL-60 Cells

Tan, Hui,Ling, Hui,He, Jie,Yi, Lan,Zhou, Jianguo,Lin, Min,Su, Qi 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.6

We investigated the effects of diallyl disulfide (DADS) on the induction of apoptosis in human Leukemia cell line HL-60 and explored the roles of mitogen-activated protein kinase (ERK and p38 MAPK) pathways in the growth inhibition and apoptosis induced by DADS. MTT assay was used to determine the DADS induced cell growth inhibition in HL-60 cells. Flow cytometry and DNA fragmentation were used to examine the roles of apoptosis in DADS-mediated cell death. Western blot analysis of the expression of phospho-MAPKs (ERK and p38) was employed to elucidate the possible mechanisms of DADS induced apoptosis. We found that growth inhibition of HL-60 cells treated with DADS exhibited a dose-dependent response (P<0.05) and DADS induced significant apoptosis. DADS at the concentration of 10 mg/L persistently activated p38 and simultaneously reduced ERK activity. PD98059, an inhibitor of ERK upstream activators MAPK kinase MKK1 and MKK2, promoted cytotoxicity and apoptosis in HL-60 cells treated with DADS. In contrast, SB203580, an inhibitor of p38, decreased cytotoxicity and apoptosis induced by DADS. Therefore, DADS can effectively inhibit the proliferation and induce apoptosis of human leukemia cell line HL-60. Inhibition of ERK signaling pathways and activation of p38 signaling pathways are likely involved in DADS induced apoptosis in HL-60 cells.

Imaging Cell Surface Glycans ofCardiomyocytes in Intact Rat Heart

Jie Rong,Jing Han,Lianshun Feng,Yanhong Tan,Qiwei Wang,Yingying Chen,Shiqiang Wang,Xing Chen 한국당과학회 2012 한국당과학회 학술대회 Vol.2012 No.1

Glycosylation is essential for proper cell signaling and embryonic development. Changes in glycosylation are often a hallmark of disease states. Cardiovascular disease has become one of the top causes of death. Many studies using rat models have related heart diseases and regulations of heart physiological functions to altered glycosylations. However, the dynamic regulation and molecular mechanism of glycosylation in heart are not clear. Rat is an important model organism for human cardiovascular disease studies. Isolated intact rat hearts are often used in physiological and pathological studies. In situ imaging biomolecules in intact heart avoid possible damage of myocyte and biased loss of cardiac myocytes during enzymatic isolation. Here, we applied the metabolic glycan labeling technique for imaging sialylation and O-linked glycosylation in living cardiomyocytes and intact rat hearts. The effects of unnatural sugars on the function of cardiomyocytes and hearts were evaluated. We found unnatural sugars did not perturb the function of cardiomyocytes and hearts. Glycan imaging revealed an interesting distribution pattern: sialic acid or O- linked glycan enriched at intercalated discs of adult rat cardiomyocytes. We also observed that the glycosylations of cardiomyocytes were altered in isoproterenol-induced cardiac hypertrophy rat models. This work extends the application of metabolic glycan labeling technique to probe glycosylations in rats and provides the first example of using this technique for in situ cellular glycans imaging in mammalian model organisms. The biological significance of altered glycosylations in cardiac hypertrophy heart is under investigation in our lab.