论转型期我国政府诚信建设

政府诚信问题是转型期中国的一大突出问题.由于受传统人治观念的影响、政府职能转变不到位、各种体制与制度及法律不健全等原因,目前我国政府诚信状况不容乐观.政府诚信建设是建立和完善整个社会诚信体系的核心,对转型期的中国来说,已迫在眉睫.因此需要从管理理念、法制保障、宣传教育、监督制约以及政府建设等诸多方面加强政府诚信建设.     

Magnetic cell sorting and flow cytometry sorting methods for the isolation and function analysis of mouse CD4＋ CD25＋ Treg cells

Objective: In this paper we compared the two methods of cell sorting (magnetic cell sorting and flow cytometry sorting) for the isolation and function analysis of mouse CD4~+ CD25~+ regulatory T (Treg) cells, in order to inform further studies in Treg cell function. Methods: We separately used magnetic cell sorting and flow cytometry sorting to identify CD4~+ CD25~+ Treg cells. After magnetic cell separation, we further used flow cytometry to analyze the purity of CD4~+ CD25~+ Treg cells, trypan blue staining to detect cell viability, and propidium iodide (PI) staining to assess the cell viability. We detected the immune inhibition of CD4~+ CD25~+ Treg cells in the in vitro proliferation experiments. Results: The results showed that compared to flow cytometry sorting, magnetic cell sorting took more time and effort, but fewer live cells were obtained than with flow cytometry sorting. The CD4~+ CD25~+ Treg cells, however, obtained with both methods have similar immunosuppressive capacities. Conclusion: The result suggests that both methods can be used in isolating CD4~+ CD25~+ Treg cells, and one can select the best method according to specific needs and availability of the methodologies.     

论杜牧“以才学为诗”

安史之乱后,盛唐诗风不复存在,大诗人杜甫开"诗世界",即开创"宋调"先声;中唐韩愈进行诗歌解构,颠覆盛唐诗已有的艺术规范;晚唐杜牧继承杜甫、韩愈开创的新诗风,并在诗歌创作中加以实践,成为了开"宋调"的另一位大诗人.宋人严羽概括的"以文为诗"、"以才学为诗"、"以议论为诗"等宋型诗要素在他诗歌创作中已有明显的表现.其"以才学为诗"主要表现为:在诗中大量用典;在自己诗中加注;好在诗中用奇字僻词,化用经学语句.杜牧"以才学为诗"的形成.与其个性、家学、时代有着密切关系,并对后世产生了深远影响.     

Book reviews

Thigh muscle volume is a useful determinant of functional fitness. However, anthropometric prediction of muscle content is influenced by the variability of adipose tissue accumulation. The aims of this study were to predict thigh muscle and adipose tissue volumes from anthropometry and to assess the validity of the method by examining the various components of the measurements and the assumptions involved. The 19 participants (9 men, 10 women; age 23-49 years) varied in adiposity. They all underwent magnetic resonance imaging (MRI) of the upper leg and the eight men and two women with the lowest adiposity underwent detailed anthropometry involving girths and skinfolds. Using MRI as the reference method, muscle volume was predicted from anthropometry using a circular concentric model, and the assumptions inherent in the method were tested further using the MRI data alone. Muscle volume was best predicted by anthropometry in the 10 leanest participants using a five-slice truncated cone model that overestimated the mean MRI value by 30% ( R 2 = 0.95; standard error of estimate = 288 cm 3 ; P ? 0.001). A single skinfold plus girth measurement at the mid-thigh almost matched its predictive ability, but with an increased bias. Measurements of leg circumference by means of the two techniques agreed well. The assumption of a circular cross-section was valid. In contrast, the agreement between skinfold thickness measured by caliper and superficial adipose tissue thickness by MRI was poor, contributing to the scatter of fat and lean area comparisons. An anterior skinfold thickness measurement underestimated the area of superficial adipose tissue at that level, particularly at the most proximal and distal sites. Although these limitations increase the uncertainties of muscle volume determination by anthropometry, they do not prevent its valid prediction in leaner individuals. The prediction of superficial adipose tissue was poorer.     

Effects of bicycle frame ergonomics on triathlon 10-km running performance

It is perceived that, during the triathlon or duathlon, cycling with a steep (>76°) rather than a shallow (?76°) frame geometry might attenuate the fatigue associated with progression from the cycle to run disciplines and improve subsequent 10-km running performance. This is based on anecdotal testimony from athletes purporting to have experienced improved performance; no empirical evidence exists. To evaluate this view, eight male triathletes completed a counterbalanced, 40-km cycle ride at two frame geometries (73° and 81°) at ~70% VO 2peak . Immediately after completion of each 40-km cycle, a self-paced 10-km treadmill time trial was undertaken, during which physiological, kinematic and performance variables were measured. The 10-km run performance (mean - s : 42:55 - 4:19 vs 46:15 - 4:52 min; P ? 0.01) and combined cycle and run performance (1:45:49 - 5:45 vs 1:50:33 - 6:08; P ? 0.001) were faster in the 81° than the 73° condition. Improvements in performance were most prominent during the first 5 km of the run (21:41 - 2:15 vs 24:15 - 2:31 min in the 81° and 73° conditions respectively). These improvements were not evident during the second 5 km of the run. No differences in physiological variables were noted, although heart rate, stride length and stride frequency were increased during the 81° condition ( P ? 0.05). Modifying frame geometry from a seat tube angle of 73° to 81° improves 10-km running and combined cycle plus run performance. These improvements in performance might relate to alterations during the cycling phase, which minimizes the 'residual effect' of this (i.e. the adverse changes in substrate availability, thermoregulatory, cardiovascular and biomechanical factors felt immediately after transition from cycling to running) and attenuates negative changes in physiological and kinematic responses during the 10-km run.     

Effect of creatine supplementation on phosphocreatine resynthesis,inorganic phosphate accumulation and pH during intermittent maximal exercise

In this study, we examined the effect of creatine ingestion on muscle power output, muscle phosphocreatine resynthesis, inorganic phosphate and pH during repeated brief bouts of maximal exercise. Nine healthy males performed maximal plantar flexion before and after creatine ingestion (20 g ·day -1 for 6 days). The experimental protocol consisted of five 8 s bouts (bouts 1-5) interspersed with 30 s recovery, followed by bouts 6 (8 s) and 7 (16 s) separated by 1 and 2 min, respectively. Muscle phosphocreatine, inorganic phosphate and pH were estimated every 16 s by 31 P magnetic resonance spectroscopy. After creatine ingestion, muscle power output increased by ~5% ( P ? 0.05) from bouts 3 to 7 and muscle phosphocreatine resynthesis increased ( P ? 0.05) during 10 min recovery. The higher phosphocreatine concentration observed after only 30 s of recovery was accompanied by lower inorganic phosphate accumulation and higher pH. Strong correlations were found between exercise power restoration and the corresponding pre-exercise phosphocreatine and inorganic phosphate concentrations and muscle pH after creatine ingestion. The better maintenance of muscle power output observed after creatine ingestion was attributed to a higher rate of phosphocreatine resynthesis, lower accumulation of inorganic phosphate and higher pH.     

Creatine kinase,myosin heavy chains and magnetic resonance imaging after eccentric exercise

The aim of this study was to examine the relationship between myosin heavy chain (MHC) release as a specific marker of slow-twitch muscle fibre breakdown and magnetic resonance imaging (MRI) of skeletal muscle injury after eccentric exercise. The effects of a single series of 70 high-intensity eccentric contractions of the quadriceps femoris muscle group (single leg) on plasma concentrations of creatine kinase and MHC fragments were assessed in 10 young male sport education trainees before and 1 and 4 days after exercise. To visualize muscle injury, MRI of the loaded thigh was performed before and 4 days after the eccentric exercise. All participants recorded an increase ( P ? 0.05) in creatine kinase after exercise. In five participants, T2 signal intensity was unchanged post-exercise compared with pre-exercise and MHC plasma concentration was normal; however, they showed an increase ( P ? 0.05) in creatine kinase after exercise. For the remaining five participants, there was an increase in T2 signal intensity of the loaded vastus intermedius and vastus lateralis. These changes in MRI were accompanied by an increase in MHC plasma concentration ( P ? 0.01) as well as an increase in creatine kinase ( P ? 0.01). We suggest that changes in MRI T2 signal intensity after muscle damage induced by eccentric exercise are closely related to damage to structurally bound contractile filaments of some muscle fibres. Additionally, MHC plasma release indicates that this damage affects not only fast-twitch fibres but also some slow-twitch fibres.     

Planum temporale asymmetry: In-vivo morphometry affords a new perspective for neuro-behavioral research

High-resolution magnetic resonance (MR) imaging today allows the in vivo quantification of the surface area of the cortex covering the planum temporale and permits assessment of the direction and degree of individual left-right asymmetry of this structure. This methodologic advance is promoting new studies on the biological mechanisms of anatomic and functional lateralization and on the structural accompaniments of disorders such as developmental dyslexia. It is important to stress that studies must agree on the definition and measurement of planum asymmetry, and we review our definition and its justification in the present article.Data obtained from normal subjects supported the assumption that planum (a)symmetry underlies functional lateralization. Thus, familial sinistrality predicted for symmetry of the planum in all eight left-handers studied. The pattern of planum symmetry in the normals was similar to that found in the post mortem studies of dyslexic individuals. Insofar as hand preference and developmental dyslexia are in part genetically transmitted, we suggest that planum symmetry may represent an inherited condition as well. Further-more, even though planum symmetry is part of the anatomic substrate of developmental dyslexia, it is unlikely that it represents a form of developmental anatomic pathology.     

A tracer study of Lebanese upper secondary school students

This paper presents data arising from a tracer study of 90 terminating Beirut upper secondary school students. Nearly all the students intended to transit to university, about half of them to science and technology programmes, and subsequently did so. Median anticipated earnings upon graduation were realistic, but a lack of information or guidance about higher education and career options was noted by a considerable proportion. The results of the study are discussed with reference to the as yet poorly elucidated dynamics of schooling with regard to attrition and transition to higher education and employment in Lebanon.     

结构动力响应仿真计算

本文提出了一种新的求解结构动力响应的仿真算法。算法原理基于求解状态方程的增广矩阵法。该算法能够给出精度今人十分满意的计算结果。