金钱榕提取物抑制3T3-L1脂肪细胞抗脂肪沉积研究(英文)

研究目的:对两个品种金钱榕(var.deltoidea和var.angustifolia)叶片提取物抑制3T3-L1脂肪细胞脂肪沉积进行研究,为基于金钱榕的抗肥胖功能产品开发提供理论基础。研究方法:用甲醇和水分别对两个品种金钱榕的叶片进行提取,并分别分析了提取物中的总黄酮含量(TFC)和总酚含量(TPC)。通过MTT法确定提取物对3T3-L1脂肪细胞的最大无毒剂量(MNTD)。然后,通过油红O染色和吸光度测定来定性和定量研究提取物对抗脂肪细胞脂肪沉积的作用。重要结论:金钱榕两个品种deltoidea和angustifolia的甲醇提取物中的TFC含量分别为1.36和1.97 g QE/100 g DW,水提取物中的TPC含量分别为5.61和2.73 g GAE/100 g DW。金钱榕deltoidea品种的甲醇和水提取物对3T3-L1细胞的MNTD分别为(300.0±28.3)和(225.0±21.2)μg/ml,而angustifolia品种的MNTDs则较低(其甲醇和水提取物的MNTDs分别为(60.0±2.0)和(8.0±1.0)μg/ml)。金钱榕两个品种的甲醇提取物和angustifolia品种的水提取物在MNTD或1/2MNTD的浓度下,均具有显著抑制前脂肪细胞的成熟的作用。因此,根据其抑制成熟脂肪细胞形成的结果可以得出金钱榕叶片提取物具有潜在的抗肥胖效果。     

Student perceptions of facilitators’ social congruence,use of expertise and cognitive congruence in problem-based learning

In problem-based learning (PBL), the role of a tutor or facilitator is different from what is typically considered as the role of a traditional teacher. In addition to being a subject-matter expert, the facilitator is also expected to be ‘socially’ and ‘cognitively congruent’. In this study, we analyze the survey responses from more than 10,000 students in order to better understand their perceptions of what makes a good or poor facilitator, and to identify specific qualities related to social congruence, cognitive congruence and use of expertise. Students’ comments for the highest and lowest scoring groups of facilitators were analyzed qualitatively using inductive data analysis strategies. The following themes were identified: for social congruence—facilitator personality, relating to students, professionalism, motivating students, and learning environment; for cognitive congruence—scaffolding learning, and communication skills; for use of expertise—content knowledge and experience, and stretching students’ learning. Coding of students’ feedback also demonstrated that students most frequently commented on issues related to facilitators’ social congruence. Our findings indicate that social congruence encompasses skills which facilitators may improve on. We also argue that understanding students’ perspectives is critical especially in a learner-centred approach such as PBL and therefore propose that our findings provide useful input for the professional development of PBL facilitators.     

The role of teacher, student and ICT in enhancing student engagement in multiuser virtual environments

This paper reviews the teaching and learning practices and processes that were adopted in a study that incorporated multi-user virtual environments to support General Paper teaching and learning. The paper discusses the roles of the teacher, student and ICT in facilitating engaged learning. As this project is the first of its kind for the subject in Singapore, the paper seeks to highlight strategies that were adopted or could have been adopted to facilitate the enactment of such teacher and student roles as well as ensure effective deployment of ICT to support engaged learning.     

What students learn in problem-based learning: a process analysis

This study aimed to provide an account of how learning takes place in problem-based learning (PBL), and to identify the relationships between the learning-oriented activities of students with their learning outcomes. First, the verbal interactions and computer resources studied by nine students for an entire PBL cycle were recorded. The relevant concepts articulated and studied individually while working on the problem-at-hand were identified as units of analysis and counted to demonstrate the growth in concepts acquired over the PBL cycle. We identified two distinct phases in the process—an initial concept articulation, and a later concept repetition phase. To overcome the sample-size limitations of the first study, we analyzed the verbal interactions of, and resources studied, by another 35 students in an entire PBL cycle using structural equation modeling. Results show that students’ verbal contributions during the problem analysis phase strongly influenced their verbal contributions during self-directed learning and reporting phases. Verbal contributions and individual study influenced similarly the contributions during the reporting phase. Increased verbalizations of concepts during the reporting phase also led to higher achievement. We found that collaborative learning is significant in the PBL process, and may be more important than individual study in determining students’ achievement.     

Analysis of streamwise conduction in forced convection of microchannels using fin approach

The effects induced by streamwise conduction on the thermal characteristics of forced convection for single-phase liquid flow in rectangular microchannel heat sinks under imposed constant wall temperature have been studied. By employing the fin approach in the first law of analysis, models with and without streamwise conduction term in the energy equation were developed for hydrodynamically and thermally fully-developed flow under local thermal non-equilibrium for the solid and fluid phases. These two models were solved to obtain closed form analytical solutions for the fluid and solid temperature distributions and the analysis emphasized details of the variations induced by the streamwise conduction on the fluid temperature distributions. The effects of the Peclet number, aspect ratio, and thermal conductivity ratio on the thermal characteristics of forced convection in microchannel heat sinks were analyzed and discussed. This study reveals the conditions under which the effect of streamwise conduction is significant and should not be neglected in the forced convective heat transfer analysis of microchannel heat sinks.     

Understanding and reducing the fear of COVID-19

Journal of Zhejiang University-SCIENCE B -     

Institutional Support for Handheld Computing: Clinical and Educational Lessons Learned

Handheld computing devices, or personal digital assistants (PDAs), are used often in the health care setting. They provide a convenient way to store and carry either personal or reference information and can be used to accomplish other tasks associated with patient care. This article reports clinical and educational lessons learned from a longitudinal institutional initiative designed to provide medical students with PDAs to facilitate patient care and assist with clinical learning.     

Objectivity of boys with attention-deficit/hyperactivity disorder (adhd) and their mothers when responding to a caricatured portrayal of adhd

In a recent theoretical model of Attention-Deficit/Hyperactivity Disorder (ADHD) it is proposed that a core deficit in response inhibition affects, among other things, an individual's objectivity in their reaction to events. In the context of this, the ability of boys diagnosed with ADHD objectively to differentiate their own behaviour from that of a caricatured portrayal of ADHD by Bart Simpson was examined. Four segments, each lasting 10–15 seconds, depicting ADHD related behaviours were isolated from a television episode of The Simpsons and shown in random order to 39 boys diagnosed with ADHD, their mothers, and two paediatricians. After watching each segment, the boys were asked to show how similar they believed their behaviours were to those exhibited by Bart Simpson by simultaneously placing two figures (one a replica of Bart and another representing themselves) on a chequer board. Mothers were subsequently administered the same procedure to indicate how they viewed their sons' behaviour in relation to Bart's. The distance measured between the two figures was representative of their levels of objectivity compared to a benchmark level set by the two paediatricians using the same chequer board procedure. While the results overall indicate that boys with ADHD and their mothers are able to make distinctions between caricatured and typical ADHD behaviours, the results are mediated by both ADHD subtype and the specific ADHD behaviour portrayed in the video segment.     

Towards precision medicine: from quantitative imaging to radiomics

Radiology (imaging) and imaging-guided interventions, which provide multi-parametric morphologic and functional information, are playing an increasingly significant role in precision medicine. Radiologists are trained to understand the imaging phenotypes, transcribe those observations (phenotypes) to correlate with underlying diseases and to characterize the images. However, in order to understand and characterize the molecular phenotype (to obtain genomic information) of solid heterogeneous tumours, the advanced sequencing of those tissues using biopsy is required. Thus, radiologists image the tissues from various views and angles in order to have the complete image phenotypes, thereby acquiring a huge amount of data. Deriving meaningful details from all these radiological data becomes challenging and raises the big data issues. Therefore, interest in the application of radiomics has been growing in recent years as it has the potential to provide significant interpretive and predictive information for decision support. Radiomics is a combination of conventional computer-aided diagnosis, deep learning methods, and human skills, and thus can be used for quantitative characterization of tumour phenotypes. This paper discusses the overview of radiomics workflow, the results of various radiomics-based studies conducted using various radiological images such as computed tomography (CT), magnetic resonance imaging (MRI), and positron-emission tomography (PET), the challenges we are facing, and the potential contribution of radiomics towards precision medicine.