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A 78-year-old Chinese woman presented with recurrent postprandial abdominal pain. Computerised tomography revealed a small bowel tumour causing volvulus of a segment of the small bowel. Laparotomy confirmed an extraluminal ileal tumour with partial volvulus of the involved small bowel segment. Small bowel resection was done. Histological and ultrastructural studies confirmed a gastrointestinal autonomic nerve tumour. We review the medical literature on this rare tumour.  相似文献   
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A prospective longitudinal study of patients with early RA was performed to examine the influence of disease duration, disease activity and physical activity on bone loss. Sixty-seven patients with non-steroid treated RA of less than 5 yr duration, including 16 patients with disease duration less than 6 months, had BMD measurements of the femoral neck and the lumbar spine over a 12-month period using dual energy X-ray absorptiometry. The BMD changes were compared with values from 72 control patients and were also correlated with serial measurements of disease activity (measured by the Stoke Index) and disability [measured by the Health Assessment Questionnaire (HAQ) score], at 3-monthly intervals over the 12-month period. No significant differences in BMD changes were found between RA patients and controls overall. Patients with disease duration of less than 6 months had significantly greater loss of BMD at the femoral neck (-3.9%, S.E.M. 1.5) than the remainder of the cohort (-0.2%, S.E.M. 0.7) (P = 0.02) and controls (-0.8%, S.E.M. 0.6). Lumbar spine BMD changes correlated with the initial Stoke Index (Rs-0.373, P = 0.01) but not mean Stoke Indices. There was no correlation of BMD changes with age or HAQ scores. These findings suggest that significant bone loss occurs within the first few months of disease in patients with RA.  相似文献   
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A genetic algorithm for multiple molecular sequence alignment   总被引:1,自引:0,他引:1  
MOTIVATION: Multiple molecular sequence alignment is among the most important and most challenging tasks in computational biology. The currently used alignment techniques are characterized by great computational complexity, which prevents their wider use. This research is aimed at developing a new technique for efficient multiple sequence alignment. APPROACH: The new method is based on genetic algorithms. Genetic algorithms are stochastic approaches for efficient and robust searching. By converting biomolecular sequence alignment into a problem of searching for optimal or near-optimal points in an 'alignment space', a genetic algorithm can be used to find good alignments very efficiently. RESULTS: Experiments on real data sets have shown that the average computing time of this technique may be two or three orders lower than that of a technique based on pairwise dynamic programming, while the alignment qualities are very similar. AVAILABILITY: A C program on UNIX has been written to implement the technique. It is available on request from the authors.  相似文献   
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Optical Splitting Trees for High-Precision Monocular Imaging   总被引:1,自引:0,他引:1  
In this article, we consider the design of monocular multiview optical systems that form optical splitting trees, where the optical path topology takes the shape of a tree because of recursive beam splitting. Designing optical splitting trees is challenging when it requires many views with specific spectral properties. We introduce a manual design paradigm for optical splitting trees and a computer-assisted design tool to create efficient splitting-tree cameras. The tool accepts as input a specification for each view and a set of weights describing the user's relative affinity for efficiency, measurement accuracy, and economy. An optimizer then searches for a design that maximizes these weighted priorities. Our tool's output is a splitting-tree design that implements the input specification and an analysis of the efficiency of each root-to-leaf path. Automatically designed trees appear comparable to those designed by hand; we even show some cases where they are superior. With the help of the optimizer, the system demonstrates high dynamic range, focusing, matting, and hybrid imaging implemented on a single, reconfigurable camera containing eight sensors  相似文献   
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Subclavian steal syndrome (SSS) appears when the origin of the subclavian artery (SA) is occluded or stenosed. Introduction of transcranial Doppler sonography (TCD) provided an opportunity to evaluate parameters of the blood flow in the vertebral (VA) and basilar artery (BA). Measurements of blood flow velocities performed at rest and after the brachial hyperemia test allow one to classify hemodynamic types of SSS. The aim of the study was to categorize types of steal and to compare the differences of flow patterns before and after percutaneous transluminal SA balloon angioplasty (SA-PTA). Fourty-eight patients with angiographically confirmed SSS (aged from 27 to 68 years, mean 53; 2/1 f/m ratio) were examined with 2 MHz range-gated, pulsed transcranial Doppler device (TC 2-64B EME). Both VA and BA were evaluated by the transoccipital approach at rest and during the brachial hyperemia. In 5 cases (10.4%) permanent reversal blood flow in the BA was observed (complete basilar steal). In flow in the BA blood flow was in the normal direction at rest and altered (reversed or decreased) when induced with brachial hyperemia test (transient basilar steal). In the next 14 patients (29.2%) permanently reversed VA blood flow was observed with only a slight or no alterations of the BA flow after the hyperemia test (complete vertebral steal). In the last 19 cases (39.6%) alterations of the VA blood flow without changes in BA flow were observed (latent vertebral steal). Between 1991 and 1994 twenty seven symptomatic patients with different hemodynamic types of SSS were treated with SA-PTA. TCD evaluation of VA's and BA using the hyperemia test was performed before, 3 to 7 days and 3 months after morphologically and hemodynamically successful subclavian artery balloon PTA. Normal results of vertebrobasilar examinations were obtained in 26 cases after this procedure. In one case the latent vertebral steal was detected. The 28 months mean follow-up revealed no significant changes in TCD flow patterns recorded from VA's and BA. After collecting data of about 60 patients with SSS we examined with TCD we conclude that: in patients with a hemodynamically significant SA stenosis the presence of reversed ipsilateral VA blood flow (a radiologic steal) its not a good determinant of either the presence or type of presenting symptoms and after successful PTA or recanalisation and PTA of SA in almost all cases we examined close to normal TCD recordings in BA and VA.  相似文献   
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The change of foot length and width with age has been reported in a few anthropometric studies in the literature. However, the relationship with body height rarely is reported, and the dynamic effect of weightbearing on foot size has not been documented. In this series, 2829 children 3 to 18 years of age of equal gender distribution were included in the study. The foot length and width on weightbearing and nonweightbearing were measured with a special precision electronic caliper. The foot length and width were found to increase linearly from the age of 3 years until 12 years in girls and 15 years in boys. This was followed by a phase during which the increase plateaued. The foot length and width increased significantly on weightbearing at all ages in both genders with a mean of 2.1 to 4.4 mm or 3.1% to 4.8%, respectively. The foot length and width also were found to correlate significantly with the body height in both genders, with a correlation coefficient of 0.96 to 0.98. No significant differences were found between the sizes of the dominant and nondominant foot in either gender.  相似文献   
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