萎叶提取物增强5-氟尿嘧啶对结肠癌细胞HT29和HCT116的生长抑制作用

研究目的：探讨萎叶（PB）提取物对5-氟尿嘧啶（5-FU）抑制结肠癌细胞HT29和HCT116生长的影响。研究方法：HT29和HCT116细胞分别给予PB、5-FU以及两种药物联合治疗24小时,应用等效线图法分析PB和5-FU的药效学相互作用,AnnexinV／PI染色法检测HT29和HCT116细胞的凋丁L=情况,高效液相色谱法排除PB和5-FU间任何可能的相互化学作用。重要结论：联合PB,低剂量5-FU可以在短时间内起到细胞毒作用,而单独应用PB或5-FU治疗较联合治疗可以诱导更多细胞发生凋亡。进一步采用等效线图法分析显示PB和5-Fu的联合作用在抑制结肠癌细胞HT29和HCT116的生长中分别体现出协同和拮抗作用。因此可以认为在HT29细胞中,PB使得较低剂量5-FU发挥最大抑制结肠癌细胞生长效果,然而在HCT116细胞中,PB没有显著降低5-FU的药物浓度,说明PB和5-FU的相互作用不仅仅体现在诱导细胞凋亡方面。     

Early visual cues associated with a directional place kick in soccer

The purpose of this paper was to establish postural cues in kicking that may be of use to goalkeepers. Eight male soccer players (age 20.5 ± 1.1 yrs; height 1.78 ± 0.053 m; mass 75.18 ± 9.66 kg) performed three types of kick: a low side-foot kick to the left hand corner of the goal, a low side-foot kick straight ahead, and a low instep kick straight ahead. Kicks were recorded by an optoelectronic motion analysis system at 240 Hz. At kicking foot take-off (about 200 ms before ball contact) the variables which were significantly different and could act as cues were support foot progression angle, pelvis rotation, and kicking hip and ankle flexion. The support foot progression angle was considered to be the most valuable of these variables as its angle coincided with the direction of ball projection. The other variables were less clear in their interpretation and so less valuable for a goalkeeper to use for decision making. Cues appearing after support foot contact were thought unlikely to be of value to a goalkeeper in their decision making. These include kicking leg knee flexion angle, and support leg shank and thigh angles.     

香港巴塞尔,沙漠中的绿洲?

本届香港巴塞尔艺术展(Art Basel HK)早在举办前就已收获了艺术圈的足够关注和期待,开幕当天雷暴雨的天气也并未消减业内人士对于此的热情。这是两年前MHC瑞士展会集团收购香港艺博会(Art HK)后的首次试水,香港艺博会自2008年成立5年后进而成为亚洲最重要的国际级博览会之一,几乎奇迹般地将香港这片艺术沙漠变为亚太地区的艺术交易重镇。对于瑞士人来说,如何借鉴巴塞尔与迈阿密海滩巴塞尔艺术展的欧美模式,使之恰当地融入亚洲艺术市场的环境中,成了主办方的首要课题。     

A bioengineering analysis of human muscle and joint forces in the lower limbs during running

A two‐dimensional, dynamic bioengineering model of the lower limbs was developed in order to estimate muscle and joint forces present during running at 4.5 m s ^‐1. Data were collected from four subjects using a force platform and cine film. Individual X‐rays and anthropometric data from the lower limbs were utilized to produce accurate bone models of the subjects’ legs. Electromyographic verification of the model was undertaken while a runner was undergoing treadmill running at 4.5 m s^‐1. Results indicate that peak muscle forces of 22 times subject body weight (22 BW) could be present in the quadriceps muscle group and 7 BW in the gastrocnemius. The anterior shin muscles were found to be active for the first 9% of stance phase only, and compressive loads of 33 BW were found in the knee joint. The relationship between these nigh forces in the lower limbs and running related injuries is discussed.     

Validity and reliability of GPS for measuring distance travelled in field-based team sports

Abstract

The aim of the present study was to examine the effects of movement intensity and path linearity on global positioning system (GPS) distance validity and reliability. One participant wore eight 1-Hz GPS receivers while walking, jogging, running, and sprinting over linear and non-linear 200-m courses. Five trials were performed at each intensity of movement on each 200-m course. One receiver was excluded from analysis due to errors during data collection. The results from seven GPS receivers showed the mean (±s) and percent bias of the GPS distance values on the 200-m linear course were 205.8 ± 2.4 m (2.8%), 201.8 ± 2.8 m (0.8%), 203.1 ± 2.2 m (1.5%), and 205.2 ± 4 m (2.5%) for the walk, jog, run, and sprint trial respectively. Walk and sprint distances were significantly different from jogging and running distances (P < 0.05). The GPS distance values on the 200-m non-linear course were 198.9 ± 3.5 m (?0.5%), 188.3 ± 2 m (?5.8%), 184.6 ± 2.9 m (?7.7%), and 180.4 ± 5.7 m (?9.8%) for the walk, jog, run, and sprint trial respectively; these were significantly lower than those for the corresponding values on the linear course (P < 0.05). Differences between all non-linear movement intensities were significant (P < 0.05). The overall coefficient of variation within and between receivers was 2.6% and 2.8% respectively. Path linearity and movement intensity appear to affect GPS distance accuracy via inherent positioning errors, update rate, and conditions of use; reliability decreases with movement intensity.     

Biomechanical analysis of the change in pistol shooting format in modern pentathlon

Abstract

Despite the importance of the Combined Event to the modern pentathlon competition, little is known about performance in the event. This study aimed to (i) identify the key variables affecting Combined Event shooting performance, and the extent to which these corresponded with those identified for precision shooting and (ii) investigate the impact of changing shooting format, and whether more successful precision shooters were also more successful in the Combined Event. Seven modern pentathletes and three pistol shooters completed precision and Combined Event trials. An opto-electronic shooting system recorded score and pistol movements, whilst force platforms recorded centre of pressure movements 1 s prior to every shot. Intra-individual analysis revealed that the extent of associations between variables was participant-specific, highlighting the need for individual analysis of performance. No participants displayed matching associations between variables for precision and Combined Event shooting, emphasising the difference between performances in the two events. Both groups experienced significantly reduced scores, and increased pistol and body movements for Combined Event shooting (P < 0.05). Despite the pistol shooters’ greater precision shooting ability, no significant differences were evident between the groups’ Combined Event performances (P > 0.05). This implies that experience in one event does not guarantee success in the other, indicating the importance of event specific training.     

PERSONOLOGICAL RESEARCH ON CREATIVITY IN THE PERFORMING AND FINE ARTS

The artist, the musican, the writer, the sculptor are all people who possess specific traits and personality attributes which the vast majority do not. Certain character traits are associated with talented artists which other people do not see in themselves. Society possesses an image of the characteristics or traits which set the creative apart from the “normal” population. In the past these generalizations may have been true: Many creative individuals may have been sensitive, temperamental, or irritable. However, the question arises whether these stereotypes are still true in today's industrial and service society.     

The misdirection of public policy: comparing and combining standardised effect sizes

Increased attention on ‘what works’ in education has led to an emphasis on developing policy from evidence based on comparing and combining a particular statistical summary of intervention studies: the standardised effect size. It is assumed that this statistical summary provides an estimate of the educational impact of interventions and combining these through meta-analyses and meta-meta-analyses results in more precise estimates of this impact which can then be ranked. From these, it is claimed, educational policy decisions can be driven. This paper will demonstrate that these assumptions are false: standardised effect size is open to researcher manipulations which violate the assumptions required for legitimately comparing and combining studies in all but the most restricted circumstances. League tables of types of intervention, which governments point to as an evidence base for effective practice may, instead, be hierarchies of openness to research design manipulations. The paper concludes that public policy and resources are in danger of being misdirected.     

The interaction of student characteristics and science teaching on student perception of the learning environment

Conclusion The interactive perspective adopted in this study suggested an alternative approach to the study of the effects of student characteristics upon their perceptions of the classroom. This perspective emphasised the necessity to examine the nature of the interaction between the student (or more exactly the student variable) and his learning environment before testing for the presence of these effects. Six relationships were consequently proposed, and both the analyses and qualitative data supported the presence of five of these in the ongoing activities of the classroom. This paper forms part of a larger study done by the author while a member of the Education Research Unit, Research School of Social Sciences, Australian National University.