Low‐intensity pulsed ultrasound ameliorates angiotensin II-induced cardiac fibrosis by alleviating inflammation via a caveolin-1-dependent pathway

ObjectiveCardiac hypertrophy and fibrosis are major pathological manifestations observed in left ventricular remodeling induced by angiotensin II (AngII). Low-intensity pulsed ultrasound (LIPUS) has been reported to ameliorate cardiac dysfunction and myocardial fibrosis in myocardial infarction (MI) through mechano-transduction and its downstream pathways. In this study, we aimed to investigate whether LIPUS could exert a protective effect by ameliorating AngII-induced cardiac hypertrophy and fibrosis and if so, to further elucidate the underlying molecular mechanisms.MethodsWe used AngII to mimic animal and cell culture models of cardiac hypertrophy and fibrosis. LIPUS irradiation was applied in vivo for 20 min every 2 d from one week before mini-pump implantation to four weeks after mini-pump implantation, and in vitro for 20 min on each of two occasions 6 h apart. Cardiac hypertrophy and fibrosis levels were then evaluated by echocardiographic, histopathological, and molecular biological methods.ResultsOur results showed that LIPUS could ameliorate left ventricular remodeling in vivo and cardiac fibrosis in vitro by reducing AngII-induced release of inflammatory cytokines, but the protective effects on cardiac hypertrophy were limited in vitro. Given that LIPUS increased the expression of caveolin-1 in response to mechanical stimulation, we inhibited caveolin-1 activity with pyrazolopyrimidine 2 (pp2) in vivo and in vitro. LIPUS-induced downregulation of inflammation was reversed and the anti-fibrotic effects of LIPUS were absent.ConclusionsThese results indicated that LIPUS could ameliorate AngII-induced cardiac fibrosis by alleviating inflammation via a caveolin-1-dependent pathway, providing new insights for the development of novel therapeutic apparatus in clinical practice.     

组织工程在软骨损伤修复方面的研究现状及应用前景

创伤和各种疾病引起软骨缺损在临床上十分常见。由于关节软骨几乎没有自身修复的能力,因此关节软骨的损伤修复已成为近年来骨科临床基础研究的一个重要课题,也是骨科界的难题之一,许多学者进行了相关研究。近二十年,随着细胞生物学和生物材料科学的发展,诞生了一门新的学科——组织工程学。利用组织工程学原理和方法能够再生软骨组织,为软骨缺损的修复提供了一种新的思路和方法。尤其是近几年来,三维立体生物可降解材料的研制成功及细胞培养技术的不断提高,为软骨缺损组织工程学修复的临床应用展示了广阔的前景。     

Perceptions of Secondary School Students with Mild Disabilities to the Academic and Social Support Mechanisms Implemented in Regular Classrooms

The Student Perceptions of Classroom Support Scale (SPCS), which measures the perceptions of students with mild disabilities of academic and social support mechanisms implemented in regular classrooms, was administered to 60 secondary school‐aged students. Data were obtained with reference to curricular, instructional, physical and peer support mechanisms. Item affectivity and multivariate analysis of variance revealed that significant differences were evident in student’s perceptions in regard to academic versus social support mechanisms. Support mechanisms rated highly by students in terms of positive academic and social outcomes often represented traditional teaching values. Conversely, support mechanisms such as one‐to‐one assistance from teacher assistants or volunteers were perceived as positive in terms of completing classroom activities, but of limited value in establishing friendships with peers. The SPCS not only provides researchers, clinicians and educators with a method of objectively evaluating students’ perceptions of support mechanisms, but also as a method of developing effective practical applications for students included in regular classrooms.     

二氧化碳冷冻刀冻融实验及数值模拟

实验研究了液体二氧化碳冷冻刀对机体组织造成的冷融过程，测定了组织内部的温度分布．实验对象为新鲜牛肉。对冷冻过程中机体组织内部的温度场和温度梯度进行了数值模拟，与实验结果吻合较好。研究工作为低温医疗手术中细胞冷冻损伤的研究提供了参考和依据。     

Coping mechanisms of part‐time students

A characteristic shared by the majority of adult students is that they are undertaking part‐time study. For these adult learners one of the major difficulties is how to find time for their study. This paper reports the coping mechanisms that part‐time adult students adopt to meet the additional demands that study puts on their existing commitments to work, family and social lives. Data were collected from 53 part‐time students in eight universities in Hong Kong through semi‐structured interviews. A model featuring three coping mechanisms (sacrifice, support and negotiation of arrangements) within four domains (self, work, family and social life) was used for the analysis. Whether or not these coping mechanisms are operationalized to a sufficient extent can have a significant impact upon the students' progress with their courses. The analytical grid provides a framework for counselling and advising adult learners. Part‐time adult students can also use the model to evaluate their own situations and determine which coping mechanisms will work for them to deal with time management issues.     

The polyadenylation code: a unified model for the regulation of mRNA alternative polyadenylation

The majority of eukaryotic genes produce multiple mRNA isoforms with distinct 3′ ends through a process called mRNA alternative polyadenylation (APA). Recent studies have demonstrated that APA is dynamically regulated during development and in response to environmental stimuli. A number of mechanisms have been described for APA regulation. In this review, we attempt to integrate all the known mechanisms into a unified model. This model not only explains most of previous results, but also provides testable predictions that will improve our understanding of the mechanistic details of APA regulation. Finally, we briefly discuss the known and putative functions of APA regulation.     

The challenge of financing higher education and the role of student loans scheme: an analysis of the student loan trust fund (SLTF) in Ghana

Student loans program is one of the most controversial phenomena in financing higher education in Ghana, but its importance as a cost sharing mechanism is incontestable. This paper describes the challenge of financing higher education in Ghana. It provides a critique of the Social Security and National Insurance Trust (SSNIT) Student Loans Scheme, and analyzes the present Student Loan Trust Fund (SLTF) policy. The paper outlines the new policy framework, critically looks at some implementation problems and provides some practical policy recommendations. The paper questions the mechanisms put in place to ensure the sustainability of the new policy? It concludes that a more efficient student loans scheme should strike the balance between lenders risk and borrowers aversion.     

油樟组织培养污染率控制试验

以油樟带芽茎段为材料,在初代培养中进行了不同表面消毒方式、不同年龄、不同季节的外植体污染率试验。结果表明,Ca(ClO)2和HgCl2的配合使用有利于污染率的降低;当年生枝条的污染率低于二年生枝条。3月采集的材料污染率低于10月。这为增加油樟组培中无菌苗的得率提供了指导,也对其它木本植物组培的研究有一定的意义。     

中国证券市场惩戒机制失效的具体表现与原因分析

证券市场惩戒机制一般分为法律惩戒机制、行政惩戒机制、自律惩戒机制、舆论惩戒机制、市场惩戒机制五个部分。在我国证券市场,这五种惩戒机制在不同程度上是失效的。造成这些惩戒机制失效的原因在于：我国上市公司与政府之间的联系还未被完全切断,国家依然为上市公司提供隐性担保。惩戒机制的失效也与我国经济转轨阶段的新兴经济体的性质紧密相关。     

Mathematical Analysis of Energy Efficiency in IEEE 802.11 DCF

The standardized IEEE ,802. II distributed coordination function （ DCF） provides a contention-based distributed channel access mechanism for mobile stations to share the wireless medium. However, when stations are mobile or portable units, power consumption becomes a primary issue since terminals are usually battery driven. This paper proposes an analytical model that calculates the energy efficiency of both the basic and the RTS/CTS access mechanisms of the IEEE 802. II protocol. The model is validated with simulation results using NS-2 simulation package. The effects of the network size, the average packet length, the initial contention window and maximum backoff stages on the energy efficiency of both access mechanisms are also investigated. Results show that the basic scheme has low energy efficiency at large packet length and large network size, and depends strongly on the number of stations and the backoff procedure parameters. Conversely, the RTS/CTS mechanism provides higher energy efficiency when the network size is large, and is more robust to variations in the backoff procedure parameters.     

句法加工的fMRI研究

句法加工是语言理解中的重要环节,句法加工的脑机制问题是心理语言学和认知神经科学的重要研究内容。功能性磁共振成像（functional magnetic resonance imaging,简称fMRI）的出现为研究语言加工提供了一种新的信息资源,它能对句子中不同位置发生的大量语义分析操作进行检测,为研究语言的脑机制提供证据。详细阐述了如何运用fMRI来研究各种句法加工,并对当前的句法加工研究及fMRI技术进行了评价。     

端粒机制与衰老和癌关系的研究进展

组织干细胞再生能力的减退可导致衰老。具有自我更新能力的干细胞由于少数癌基因突变被赋予恶性化,而功能交叉的肿瘤抑制机制-p16 INK4 a-Rb,ARF-p53和端粒-则避免这种恶性化的发生。然而这些信号途径同时可能会抑制干细胞的生存,因此促成衰老。文章综述端粒机制及其在降低干细胞修复再生能力而促进衰老过程中的作用,以及衰老和癌两者相互间的关系。     

电大实践教学实证研究——以河北电大为例

《国家中长期教育改革和发展规划纲要（2010—2020年）》为电大的发展提供了新的历史机遇。但电大自身发展中,从思想观念到能力建设都面临严峻的挑战。调研结果显示,实践教学已成为提高教学质量的“瓶颈”。电大要从观念认识、基础设施、师资、教学计划、运行机制等方面入手,切实使实践教学质量取得突破性进展,带动电大的教学改革向纵深发展。     

Rapid prototyping technology and its application in bone tissue engineering

Bone defects arising from a variety of reasons cannot be treated effectively without bone tissue reconstruction. Autografts and allografts have been used in clinical application for some time, but they have disadvantages. With the inherent drawback in the precision and reproducibility of conventional scaffold fabrication techniques, the results of bone surgery may not be ideal. This is despite the introduction of bone tissue engineering which provides a powerful approach for bone repair. Rapid prototyping technologies have emerged as an alternative and have been widely used in bone tissue engineering, enhancing bone tissue regeneration in terms of mechanical strength, pore geometry, and bioactive factors, and overcoming some of the disadvantages of conventional technologies. This review focuses on the basic principles and characteristics of various fabrication technologies, such as stereolithography, selective laser sintering, and fused deposition modeling, and reviews the application of rapid prototyping techniques to scaffolds for bone tissue engineering. In the near future, the use of scaffolds for bone tissue engineering prepared by rapid prototyping technology might be an effective therapeutic strategy for bone defects.     

大学生急性闭合性软组织损伤的治疗与预防

随着大学生参加体育锻炼的积极性日益高涨,在体育锻炼中的运动损伤,是大学生碰到的一个难题,因此,为了维护学生身体健康,保证体育活动在高校的顺利开展,如何预防大学生在体育锻炼中发生的运动损伤就显得格外重要。闭合性软组织损伤是比赛训练和教学过程中常见的运动损伤,分析了急性闭合性软组织损伤的病理过程,处理原则,操作方法,并对怎么样预防做了初步探析。     

城乡统筹背景下职业教育面临的挑战及对策

统筹城乡发展战略的贯彻实施,既为职业教育的大发展提供了前所未有的发展空间,也使我国职业教育面临一系列挑战。要实现职业教育与城乡统筹发展的良性互动,需着力做好职业教育为城乡统筹发展服务的战略规划,加大各类资金对职业教育的投入力度,加强对职业教育资源的优化整合,将农村职教作为发展职业教育的重点,充分发挥市场机制在推动职业教育发展中的重要作用,构建职业教育的创新机制。     

Most Effective Lab Exercises

A data base program that includes some inquiry capabilities can be effective in illustrating Prolog concepts. Having students do essentially the same task in Pascal first reinforces the concepts of relationships in a data base, and provides a firm foundation of understanding of the mechanisms used in a Prolog program.     

The architecture of human information processing: Empirical evidence

This article outlines a path analytic interpretation of data collected in light of a theoretical formulation of a dynamic model of memory, which provides a perspective on the human information processing system as a whole. The model of memory represents an attempt to integrate the relatively static models of memory structures with the more dynamic concepts underlying research on control and processing mechanisms. The outcomes of the study emphasise the role of relational knowledge (taxotomic subject matter structures), strategic knowledge (procedural algorithms) and empirical knowledge (based on first hand experience) in cognitive skill performance.     

The (De-)evolution of Evolution Games: A Content Analysis of the Representation of Evolution Through Natural Selection in Digital Games

Given the diversity and complexity of education game mechanisms and topics, this article contributes to a theoretical understanding of how game mechanisms “map” to educational topics through inquiry-based learning. Namely, the article examines the presence of evolution through natural selection (ENS) in digital games. ENS is a fundamentally important and widely misunderstood theory. This analysis of ENS portrayal in digital games provides insight into the use of games in teaching ENS. Systematic database search results were coded for the three principles of ENS: phenotypic variation, differential fitness, and fitness heritability. Though thousands of games use the term evolution, few presented elements of evolution, and even fewer contained all principles of ENS. Games developed to specifically teach evolution were difficult to find through Web searches. These overall deficiencies in ENS games reflect the inherent incompatibility between game control elements and the automatic process of ENS.