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1.
Background and objectivesRecent research has identified neighborhoods as an important contributor to later-life frailty. However, little is known about how neighborhood resources are associated with frailty trajectories over time, especially in developing countries. This study examines the impact of neighborhood physical and social resources on the trajectories of frailty over time among older people in China.Research design and methodsUsing the four waves of the China Health and Retirement Longitudinal Study (2011–2018), 5673 respondents aged 60 and above at baseline were included for analyses. Multilevel growth modeling was fitted to estimate the effects of neighborhood resources on frailty trajectories over a 7-year period, controlling for individual-level characteristics.ResultsOlder Chinese people who lived in neighborhoods with better basic infrastructures and a greater number of voluntary organizations were less frail at baseline. Accessible exercise facilities were associated with a lower initial level of frailty only among rural older adults, while higher community-level socioeconomic status (SES) was associated with a lower initial level of frailty only among urban older adults. Over the 7-year follow-up period, better basic infrastructures and accessible exercise facilities were associated with a slower increase rate of frailty scores among rural residents.Discussion and implicationsNeighborhood resources are important contributors to the level of frailty among older Chinese people. Our findings of significant urban-rural differences have important implications for designing and implementing infrastructure development and community building programs in rural and urban China.  相似文献   
2.
微乳对难溶性药物增溶机理的研究   总被引:17,自引:1,他引:16  
目的:初步探讨微乳对难溶性药物的增溶机理.方法:经处方筛选及相图研究确定(BL-9/正丁醇3∶1)/油/水比例为9∶1∶40的微乳处方;以二氢吡啶类药物为模型药物,测定其在微乳、胶束和油相中的溶解度及油/水分配系数;根据化学结构,采用计算机软件计算药物的特性参数,并结合模型药物的特性分析微乳增溶难溶性药物的机理.结果:微乳对药物的增溶效果远大于油相和胶束,并随药物的脂溶性和空间结构的改变而变化.结论:微乳可用于增溶难溶性药物,且脂溶性越大,空间位阻越小,增溶效果越明显.  相似文献   
3.
This study describes a method for determining the number of radiographic rooms devoted to emergency radiology that would be required to keep mean patient waiting time at a desired level. A desired mean waiting time for patients must be determined. In our setting, a mean waiting time of 8 minutes resulted in few complaints. The waiting time then sets the required utilization rate of available capacity. Daily and hourly volume and variability in volume of examinations were measured over a 3-month period. This represents the demand. The needed number of rooms is determined by comparing demand with effective available capacity for different numbers of rooms. To maintain an 8-minute mean waiting time, 50% utilization of capacity is required. Mean demand on Sundays is 176 examinations. Five rooms are required, since this gives a 180-examination effective capacity. Using waiting time as the primary decision criterion for making capacity decisions in emergency radiology has several advantages: the method is easy to use, volume variability is taken into account, and the focus is on service to patients.  相似文献   
4.
腮腺间隙良性肿瘤的MRI诊断   总被引:1,自引:0,他引:1  
目的探讨腮腺间隙常见良性肿瘤的影像特征及其诊断与鉴别诊断。方法良性肿瘤20例,包括多形性腺瘤13例、乳头状淋巴囊腺瘤3例、淋巴管瘤2例、血管瘤1例、脂肪瘤1例。经手术病理证实15例,穿刺活检证实4例,典型MR特征结合病史确诊1例。结果13例多形性腺瘤中有11例位于腮腺浅叶,2例位于深叶;9例表现为均匀等T1长T2信号.4例在T2WI上信号明显不均匀;静脉注射Gd—UIPA后3例瘤实质均匀强化,4例增强后明显不均匀强化。3例Warthin瘤中2例发生于一侧,1例累及双侧腮腺,在T1WI上呈低信号,T2WI上信号等于或低于正常腺实质,增强后无明显强化。2例淋巴管瘤呈明显长T1长T2信号,并有多房现象。1例血管瘤信号不均质,呈明显长T1长T2信号,静1脉注射Gd—DTPA后病变往往显著异常强化。1例脂肪瘤在T1WI及T2WI上均表现为明显高信号强度。结论运用MR成像研究腮腺间隙的良性肿瘤,有利于疾病的定位,有助于病变的诊断与鉴别诊断。  相似文献   
5.
Simulation of space adaptation syndrome on earth   总被引:2,自引:0,他引:2  
Summary The three Spacelab D-1 Scientist Astronauts were exposed to a 11/2 h 3 g centrifuge run in the supine position, resulting in a linear 3 g acceleration in the x-direction. They used their space experience to evaluate their readapting to normal gravity and compared their observations with Space Adaptation Syndrome. After the centrifuge runs, the vestibular visual system appeared to be modified in a very specific and reproducible manner. Readapting to the normal 1 g environment took at least 6 h. During this period there was a striking similarity to the astronaut's experience during adaptation to weightlessness in space. A series of vestibular tests were then performed, confirming these subjective findings.  相似文献   
6.
The Equal Environments Assumption (EEA) in twin studies of eating pathology was investigated by examining the hypothesis that twin resemblance for eating attitudes and behaviors is affected by their degree of physical similarity. Eating attitudes and behaviors were assessed in 338 female adolescent twin pairs with a revised version of the Eating Disorder Inventory (EDI). General physical similarity as well as body size/shape similarity were assessed using ratings of color photographs, ratings of body shape, and body mass index. All physical similarity assessments were conducted blind to twin zygosity. Significant associations between physical similarity and twin similarity for eating attitudes and behaviors were not found. Mean EDI within-twin pair absolute difference scores did not differ significantly among more versus less physically-similar groups. Additionally, correlation and regression analyses failed to find a significant association between EDI absolute difference scores and physical similarity indices. The current findings provide support for the EEA in twin studies of eating attitudes and behaviors.  相似文献   
7.
Summary The intrarenal volumes of distribution of125I-polyvinyl pyrrolidone and51Cr-labelled red cells have been examined in rabbits under conditions of severe hydropenia and starvation-induced polyuria, and in rabbits under control conditions. The PVP space was significantly reduced, and the ratio [red cell space]:[red cell space + PVP space] significantly elevated, in the outer cortex of kidneys of hydropenic rabbits, and in the papilla of polyuric rabbits. It is suggested that the former may in some manner result from a reduction in the total cortical vascular space, whereas the latter reflects variations of medullary and appillary interstitial tonicity under these conditions.  相似文献   
8.
Decompression operation of the optic canal via the nasal path under endoscope is widely used, but it is both a challenging and controversial method. Unsatisfactory results were largely associated with otolaryngologists' limited understanding of the real anatomical situations of the optic canal before operation. To provide otolaryngologists with the real situations and data preoperation, multislice helical CT was used to reconstruct the images of the optic canal. Using multislice helical CT‐aided three‐dimensional reconstructive methods in combination with direct anatomic measurement, we dissected and analyzed the shape of the optic canal and its anatomic relationship with the adjoining structures in 40 intact postmortem skull samples. The In‐Space technique clearly showed the structure and the related region of the optic canal. The virtual endoscopy technique showed superbly the spatial appearance and topography of the inner optic canal and also gave the inner structure of the optic canal optically. There was no statistic difference in three‐dimensional reconstructive data with that obtained by anatomical measurements and thus can be used to directly instruct the clinic operation. These results demonstrate that a combined In‐Space technique with virtual endoscopy can accurately define the subtle structure and the related region of the optical canal. In conclusion, multislice helical CT‐based three‐dimensional reconstruction is of important value for clinical operations. Anat Rec, 2008. © 2008 Wiley‐Liss, Inc.  相似文献   
9.
This work emphasizes a better understanding of the origin of human thermal discomfort under heterogeneous but steady environments, in subjects in the vicinity of physiological and sensory thermoneutrality. The knowledge of skin temperatures allows a psychophysiological study aiming at linking the body thermal state (local and global) to thermal sensation (perceptive and affective judgements). By using two driving simulators, 345 subjects were exposed to different thermal environments, modulated by factors such as the air distribution in the automotive cockpit or the clothing insulation (winter or summer). This work shows that consideration of the local thermal state is essential for the evaluation of thermal comfort in the case of non-uniform environments. Our experimental conditions point out that the overall sensation of discomfort is quantitative, with local unpleasantness needing to be felt for a certain number of body surfaces. A local origin is suggested for cold discomfort, in opposition to the global characteristics of warm discomfort.  相似文献   
10.
Three experiments investigated the mechanisms by which we estimate Euclidean distances on the basis of kinaesthetic cues. In all experiments, blindfolded participants followed straight and curvilinear paths with a stylus. Then, with a straight response movement, they estimated the distance between the end-points of the previously explored path. Experiment 1 was designed to validate the hypothesis—made on the basis of results from a previous study—that errors in the kinaesthetic estimations of distances (detour effect) originate from the difficulty to decompose the displacement vector into relevant and irrelevant components, which would become more severe at points of inflection. Using elliptic paths (no inflections), we demonstrated that errors are indeed reduced considerably. The role of the orientation of the work plane was investigated in Experiment 2 in which the same paths used in our previous study were oriented in the frontal rather than the horizontal plane. The results indicate that the detour effect is independent of the orientation. Moreover, despite the asymmetry that gravity introduces between upward and downward movements, errors in the two directions are almost identical. Experiment 3 addressed two issues. First, we demonstrated that introducing a delay between the exploration of the path and the response did not alter significantly the pattern of errors. By contrast, we demonstrated that errors are severely reduced when the number of paths to be explored is reduced by half. The results of the three experiments are discussed within the context of current theories of sensori-motor coding.  相似文献   
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