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51.
STUDY OBJECTIVES: To define a set of orthostatic vital signs that minimize the frequency of false-positives among healthy individuals while maximizing sensitivity in detecting acute moderate blood loss and to determine the sensitivity and specificity of this optimized tilt test in detecting acute moderate blood loss. DESIGN AND INTERVENTION: Postural vital signs were recorded in a standardized manner before and after 450-mL phlebotomy. Paired comparisons were done for a variety of criteria for a positive tilt test using receiver-operating characteristic curves. SETTING AND TYPE OF PARTICIPANTS: Three hundred forty-five healthy euvolemic adult volunteer blood donors were tested at three community blood donation centers over a one-year period. Subjects were prospectively divided into group 1 (less than age 65; 301) and group 2 (age 65 or older; 44). MEASUREMENTS AND MAIN RESULTS: For each combination of pulse and blood pressure in group 1, a change in pulse alone had the same or higher sensitivity with at least the same specificity. Pulse alone was similarly superior in group 2 compared with previously published combinations of pulse and blood pressure. Even the optimized tilt test had limited sensitivity in detecting acute moderate blood loss with high specificity. CONCLUSION: In applying the tilt test to young adults without cardiovascular disease, pulse measurement usually is all that is necessary. 相似文献
52.
Radiographic computed tomography and magnetic resonance imaging are the procedures of choice in the diagnosis of patients with suspected pituitary gland abnormalities. Several cases are presented where the diagnostic value of such procedures in patients with diseases affecting the pituitary gland is demonstrated. 相似文献
53.
We established an in vitro model of the phagocytosis of Mycobacterium tuberculosis by human peripheral blood monocytes to evaluate the subsequent inhibition of intracellular replication of the organism. Highly purified T cells (94% CD3(+)/CD16(-)) or natural killer (NK) cells (96% CD16(+)/CD3(-)) isolated by Percoll discontinuous density gradient of peripheral blood mononuclear cells were incubated with M. tuberculosis-infected monocyte monolayers. Monocytes were lysed immediately and at 4, 7, and 10 d after infection for quantification of intracellular replication, which was assessed by quantitative plating techniques as colony-forming units (CFU). Whereas control monocytes permitted intracellular replication, T cells activated monocytes to kill 77% (p < 0.01) of intracellular M. tuberculosis compared with control monocytes by 10 d after infection. NK cells activated monocytes to kill 84% (p < 0.01) of M. tuberculosis in comparison with control monocytes. Lymphokine (IL-2)-activated-killer (LAK) cells were capable of activating monocytes to kill 97% (p < 0.01) of the intracellular organisms compared with control monocytes. In purified protein derivative (PPD)-positive donors, PPD-specific-CD4(+) lymphocytes stimulated monocytes to kill intracellular M. tuberculosis in a Class II major histocompatibility complex-restricted manner. In contrast, in PPD-negative donors, CD4(-) lymphocytes activated monocytes in a genetically unrestricted manner. Both T cell supernatant and NK cell supernatant generated from cocultivation with M. tuberculosis-infected monocytes also activated monocytes to augment mycobactericidal function. In conclusion, T cells, NK cells, LAK cells, and their supernatants activated mycobactericidal function of monocytes, although these pathways of activation differed in terms of antigenic specificity and genetic restriction. 相似文献
54.
55.
Excretion was studied of catecholamines and diphenilamine (DOPA) in 310 patients with carcinoma of the stomach and large intestine and 43 patients with non-malignant diseases. The oncological patients showed decrease in activity of the mediator link of the sympathoadrenal system (SAS) as well as its reserves but there was no association with sex, age, location or histological structure. Three types of SAS functioning were identified, such as compensation, overstrain and emaciation. Surgical intervention led to activation of the hormonal link and exhaustion of the system's reserves. Two kinds of sympathoadrenal response to stress were described--adequate and inadequate. In the former type, phases of stress remain as they are, unchanged, as are time periods of formation thereof, while under the latter one time periods of the phases formation or formation thereof get disordered. 相似文献
56.
Chengsheng Ni Mark Cassidy John T.S. Irvine 《Journal of the European Ceramic Society》2018,38(16):5463-5470
Image analysis and quantification were performed on porous scaffolds for building SOFC cathodes using the two types of YSZ powders. The two powders (U1 and U2) showed different particle size distribution and sinterability at 1300?°C. AC impedance on symmetrical cells was used to evaluate the performance of the electrode impregnated with 35-wt.% La0.8Sr0.2FeO3. For example, at 700?°C, the electrode from U2 powder shows a polarization resistance (Rp) of 0.21?Ω?cm2, and series resistance (Rs) of 8.5?Ω?cm2 for an YSZ electrolyte of 2-mm thickness, lower than the electrode from U1 powder (0.25?Ω?cm2 for Rp and 10?Ω?cm2 for Rs) does. The quantitative study on image of the sintered scaffold indicates that U2 powder is better at producing architecture of high porosity or long triple phase boundary (TPB), which is attributed as the reason for the higher performance of the LSF-impregnated electrode. 相似文献
57.
Image Analysis and Modeling of the Orientation of Pores in a Constrained Film on a Rigid Substrate 下载免费PDF全文
The nature of porosity in functional materials is often a critical parameter in determining their functionality, for example, in structure materials and fuel cell electrodes. Here, we study the development of the anisotropy of porous yttria‐stabilized zirconia (YSZ), focusing particularly upon the contribution of pore orientation to this anisotropy. Simulation from when the ink is deposited on the surface of a rigid substrate shows that platelike pores are found tend to align along the transverse direction of the substrate. Cross‐sectional image analysis of the pores from the attendant pores of YSZ particles or pore‐forming agent (PFA) matches with the simulated modeling when materials transport is insignificant in determining the shape of pores. The anisotropy created in the densification stage is separated from that in the green body by analyzing the image of porous structures formed with spherical glassy carbon which is unable to contribute to anisotropy during green‐state processing. 相似文献
58.
The changes occurring in torque during PVC processing in a torque rheometer have been interpreted in terms of the destruction of the supramolecular structure followed by a fusion of the grain fragments. In contrast to changes in torque, changes in elasticity occur in the absence of grain breakdown. It is proposed that the change in elasticity during processing is the result of changing crystallinity of the resin. In the early stages of processing, crystallites melt and elasticity decreases. As grains fuse together, new crystallites are formed in the previously unoccupied grain boundaries and the elasticity increases. 相似文献
59.
Why do fish strand? An analysis of ten years of flow reduction monitoring data from the Columbia and Kootenay rivers,Canada 下载免费PDF全文
Stranding of fish due to flow reductions has been documented in the near shore of the Columbia and Kootenay Rivers, Canada, and can result in sub‐lethal or lethal effects on fish. Ten years (1999–2009) of monitoring data have been collected at sites below two hydro‐electric dams (Hugh‐L‐Keenleyside and Brilliant Dam) following flow reductions. A generalized linear mixed effects model analysed the probability of a stranding event in relation to environmental and operational variables including the rate of change in the water levels, the duration of shoreline inundation prior to a reduction (wetted history), the river stage, the magnitude of the reduction, distance downstream from the dam, time of day, day of year (season) and whether a site had been physically altered to mitigate stranding. The results demonstrated statistically significant effects on stranding risk from minimum river stage, day of the year and whether a site had been physically re‐contoured. The combination of investigated factors giving the highest probability of stranding was a large magnitude reduction completed in the afternoon in midsummer, at low water levels when the near shore had been inundated for a long period. This research is significant in its approach to assessing years of ecosystem scale monitoring data and using the modelling results to determine ways for these findings to be applied in regulated river management to minimize fish stranding. It also highlighted data gaps that require addressing and provides ecosystem scale results to compare with stranding studies carried out in mesocosms. © 2014 The Authors. River Research and Applications published by John Wiley & Sons Ltd. 相似文献
60.
Oncocytic lesions of the caruncle and other ocular adnexa 总被引:2,自引:0,他引:2
This is a clinicopathologic study of 18 oncocytic lesions involving the ocular adnexa. These lesions most commonly occur in elderly patients (median age 73), and there is a striking predilection for women. The broad spectrum of lesions included oncocytic adenomatous hyperplasia, oncocytomas, and oncocytic carcinoma. Ten lesions, all of which were oncocytomas, involved the caruncle, four the conjunctiva, and one the mucocutaneous junction of the eyelid. Two tumors involved the lacrimal sac and one the lacrimal gland. A review of the literature disclosed only 17 previously reported oncocytic lesions of the ocular adnexa. A small yellowish-tan or reddish caruncular mass, especially in an elderly woman, should alert the ophthalmologist to consider the possibility of oncocytoma in his differential diagnosis. 相似文献