Hepatitis G virus RNA is common in AIDS patients'' plasma but is not associated with abnormal liver function tests or other clinical syndromes

OBJECTIVE: To determine whether postmenopausal oestrogen replacement therapy affects carotid artery pulsatility index. DESIGN: A prospective double-blind placebo controlled trial. SETTING: University associated teaching hospital. PARTICIPANTS: Twenty-eight postmenopausal women who were more than 12 months postmenopausal and who had not taken exogenous oestrogen. INTERVENTIONS: Independent randomisation to receive oral oestradiol (2 mg daily) or placebo for 20 to 24 weeks. MAIN OUTCOME MEASURES: Internal carotid artery Doppler pulsatility index, measured within one centimetre of the carotid bifurcation. RESULTS: Replicate data were available from 27 women. The mean pulsatility index decreased by -0.11 in 15 women receiving oestradiol, compared with a mean rise of 0.05 in the 12 women who received placebo (P = 0.006, 95% CI for treatment difference 0.06-0.31). CONCLUSIONS: Oestrogen replacement decreases postmenopausal carotid artery pulsatility index, probably reflecting decreased peripheral vascular resistance. This is a further mechanism whereby hormone replacement therapy may impart cardiovascular protection.     

A technique for assessment of torso kinesiology

A technique is described for monitoring and analysis of the angular displacement of the human torso. The technique is based on the use of miniature electromechanical inclinometers and video recording. The system was developed for continuous measurement of the angular displacement of spinal segments in the sagittal plane during all stages of lifting. Angular displacements of the cervical, thoracic and lumbar regions were obtained from a dynamic lifting case study using a digital processing system. The geometrical changes of the torso during five prescribed stages were measured. The system revealed good accuracy with high correlation coefficient scores for a wide range of lifting tasks in a comparative laboratory study. This paper describes the monitoring technique; the system's advantages, disadvantages and measuring accuracy are discussed.     

Evidence for "twisted plane" undulations in golden hamster sperm tails

Motile spermatozoa from the golden hamster have been arrested by rapid freezing and then fixed with glutaraldehyde at low temperature after substitution with ethylene glycol. As far as can be judged, the flagellar waveforms thus stabilized are similar to those seen in living sperm; in contrast, fixation in glutaraldehyde, without prior freezing, induces agonal changes in flagellar conformation. The characteristics waveform after freeze substitution contains three bends. Approx. half of these flagella are entirely planar. The rest are three dimensional, with the third bend displaced in a regular way from the plane containing the proximal two bends. From the geometry of these flagella, it is concluded that the plane of action of a given bending cycle undergoes a clockwise twist (from a forward viewpoint) as the cycle is succeeded by new bending cycles. This "twisted plane" undulation is quite different from helical movement. The twisting seems to occur abruptly, between cycles, as if each bending cycle has a preferred plane of action. The mechanism underlying the twisting is uncertain. However, on the basis of the angular displacements between the preferred planes, and the findings from electron microscopy, the following idea is presented as a working hypothesis: that, if the most proximal plane of bending is topographically determined by peripheral doublet 1, then successive distal planes of action are influenced predominantly by doublets 2, 3, etc., in clockwise sequence. The merits and weaknesses of this hypothesis are discussed.     

Results demonstrating techniques for enhancing electrochemical reactions involving iron oxide in slags and C in liquid iron

Two techniques are described for the enhancement of the kinetics of reduction of iron oxide from slags by carbon in molten iron. Laboratory experiments have shown that the rate of iron oxide reduction by carbon-saturated iron can be increased by 5 to 10 times when the reaction is carried out under a reduced-pressure atmosphere. This effect is thought to be the result of the increased volumetric gas evolution through the slag layer and the associated increase in slag stirring. A model is presented, which relates the mass-transfer coefficient for ferrous ions in the slag to its stirring that is controlled by varying the ambient pressure. Additional laboratory experiments examined the electrochemical nature of iron oxide reduction from slag by carbon in liquid iron. Results indicate that the reduction of iron oxide from slag is increased in the presence of an applied electric field. The external circuit allows for the separation of the half-cell reactions associated with iron oxide reduction and decarburization and increases the reaction area available for the individual reactions. These results have significant implications for several important slag metal reactions, which occur during ironmaking and steelmaking operations.     

Passengers’ perceived ability to get out safely from an underground train station in an emergency situation

Cognition, Technology & Work - Many recent studies have been done on the development of evacuation systems and plans. There are also several studies on human behaviour in fire. However, little...     

“与自然共生”：英国儿童游戏场地改造

风景园林实践在很大程度上受到政府决策的影响,以英国英格兰地区为例,劳动党政府于2008年提出的《儿童计划》和《游戏策略》,在为儿童游戏场地的更新和建设提供资金支持的同时,也间接推动了儿童场地设计导则与标准的发展。然而随着2010年政府换届,儿童户外游戏场地发展方案被移出了英国国家发展计划。将着重介绍在政策变化的背景下,于英格兰北部谢菲尔德市进行的名为“与自然共生”政府资助项目的实践经验,重点探究在政策引导的背景下,通过儿童户外游戏场地自然化改造的方式对社区户外空间进行适儿化提升的过程、方式和成果。将从多元参与协同工作的机制、儿童参与社区改造的方式以及儿童游戏场地的游戏价值提升等多个方面阐释该项目,为中国“十四五”规划背景下儿童友好型城市建设中社区环境优化提升面临的机遇与挑战提供基于英国经验的应对策略;对因地制宜地建设中国儿童友好城市及社区提供基于前沿实践的参考和建议。     

环境行为学视角下建成环境与儿童出行 影响机制研究

儿童依赖建成环境,并通过基本的出行行为满足其 自身发展的各项必要需求,其中儿童独立出行水平和出行方式 至关重要。随着中国城镇化持续推进,大城市边缘的小城镇在 迅速发展的同时,其建成环境也给儿童出行带来了一定安全隐 患,儿童出行安全问题值得关注。从环境行为学视角,结合既 往文献将儿童出行的影响因素归纳整理成个体、环境和其他因 素,随后对长沙市岳麓区莲花镇第五实验小学1 509名6~12 岁儿童及其家长展开实证调查和数据统计分析。结果显示： 儿童和家长对环境的安全感知会对儿童的出行决策产生较大 影响,机动车交通量及速度、交叉路口、道路复杂程度、步 道和自行车道及其基础设施设置、自然水体等是主要的显著 影响因素。据此,从空间布局、道路设计、交通设施配置和 社会环境方面提出了提升儿童出行安全水平的小城镇规划策 略建议。     

The influence of antibodies to TNF-alpha and IL-1beta on haemodynamic responses to the cytokines, and to lipopolysaccharide, in conscious rats

Male, Long Evans rats (350-450 g) were anaesthetized and had pulsed Doppler probes and intravascular catheters implanted to allow monitoring of regional (renal, mesenteric and hindquarters) haemodynamics in the conscious state. Our main objectives were to:- assess the effects of administering human recombinant tumour necrosis factor (TNF)-alpha and human recombinant interleukin-1 (IL-1)beta, alone and together; determine the influence of pretreatment with a mixture of antibodies to TNF-alpha and IL-1beta on responses to co-administration of the cytokines; ascertain if pretreatment with a mixture of the antibodies to TNF-alpha and IL-1beta had any influence on the responses to lipopolysaccharide (LPS). TNF-alpha (10, 100 and 250 microg kg(-1), in separate groups, n=3, 9 and 8, respectively) caused tachycardia (maximum delta, +101+/-9 beats min(-1)) and modest hypotension (maximum delta, -10+/-2 mmHg), accompanied by variable changes in renal and mesenteric vascular conductance, but clear increases in hindquarters vascular conductance; only the latter were dose-related (maximum delta, +6+/-6, +27+/-9, and +61+/-12% at 10, 100 and 250 microg kg(-1), respectively). IL-1beta (1, 10, and 100 microg kg(-1) in separate groups, n = 8, 8 and 9, respectively) evoked changes similar to those of TNF-alpha (maximum delta heart rate, +69+/-15 beats min(-1); maximum delta mean blood pressure, -14+/-2 mmHg; maximum delta hindquarters vascular conductance, +49+/-17%), but with no clear dose-dependency. TNF-alpha (250 microg kg(-1)) and IL-1beta (10 microg kg(-1)) together caused tachycardia (maximum delta, +76+/-15 beats min(-1)) and hypotension (maximum A, -24+/-2 mmHg) accompanied by increases in renal, mesenteric and hindquarters vascular conductances (+52+/-6%, +23+/-8%, and +52+/-11%, respectively). Thereafter, blood pressure recovered, in association with marked reductions in mesenteric and hindquarters vascular conductances (maximum delta, -50+/-3% and -58+/-3%, respectively). Although bolus injection of LPS (3.5 mg kg(-1)) caused an initial hypotension (maximum delta, -27+/-11 mmHg) similar to that seen with co-administration of the cytokines, it did not cause mesenteric or hindquarters vasodilatation, and there was only a slow onset renal vasodilatation. The recovery in blood pressure following LPS was less than after the cytokines, and in the former condition there was no mesenteric vasoconstriction. By 24 h after co-administration of TNF-alpha and IL-1beta or after bolus injection of LPS, the secondary reduction in blood pressure was similar (-16+/-2 and -13+/-3 mmHg, respectively), but in the former group the tachycardia (+117+/-14 beats min(-1)) and increase in hindquarters vascular conductance (+99+/-21%) were greater than after bolus injection of LPS (+54+/-16 beats min ' and +439%, respectively). Pretreatment with antibodies to TNF-alpha and IL-1beta (300 mg kg(-1)) blocked the initial hypotensive and mesenteric and hindquarters vasodilator responses to co-administration of the cytokines subsequently. However, tachycardia and renal vasodilatation were still apparent. Premixing antibodies and cytokines before administration prevented most of the effects of the latter, but tachycardia was still present at 24 h. Pretreatment with antibodies to TNF-alpha and IL-1beta before infusion of LPS (150 microg kg(-1) h(-1) for 24 h) did not affect the initial fall in blood pressure, but suppressed the hindquarters vasodilatation and caused a slight improvement in the recovery of blood pressure. However, pretreatment with the antibodies had no effect on the subsequent cardiovascular sequelae of LPS infusion. the results indicate that although co-administration of TNF-alpha and IL-1beta can evoke cardiovascular responses which, in some respects, mimic those of LPS, and although antibodies to the cytokines can suppress most of the cardiovascular effects of the cytokines, the antibodies have little influence on the haemodynamic responses to LPS, possibly because, during infusion of LPS, the sites of production and local action of endogenous cytokines, are not accessible to exogenous antibodies.