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排序方式: 共有1002条查询结果,搜索用时 15 毫秒
81.
82.
Kidney stones are a common problem for which inadequate prevention exists. We recruited ten recurrent kidney stone formers with documented calcium oxalate stones into a two phased study to assess safety and effectiveness of Cystone®, an herbal treatment for prevention of kidney stones. The first phase was a randomized double-blinded 12 week cross over study assessing the effect of Cystone® vs. placebo on urinary supersaturation. The second phase was an open label one year study of Cystone® to determine if renal stone burden decreased, as assessed by quantitative and subjective assessment of CT. Results revealed no statistically significant effect of Cystone® on urinary composition short (6 weeks) or long (52 weeks) term. Average renal stone burden increased rather than decreased on Cystone®. Therefore, this study does not support the efficacy of Cystone® to treat calcium oxalate stone formers. Future studies will be needed to assess effects on stone passage, or on other stone types. 相似文献
83.
针对医学X线计算机断层(Computed Tomography,CT)图像,提出了一种基于尺度不变特征变换(Scale InvariantFeature Transform,SIFT)特征和近似最近邻算法的检索方法。首先通过SIFT算法得到图像的特征点和相应的特征向量,再采用近似最近邻算法进行SIFT特征向量的匹配搜索,得到数据库中与参考图像最相似的图像序列。实验结果表明,该法能检索到与目标图像细节相符的结果,大大提高了检索速度。与传统的基于纹理的检索方法相比,查准率和检索结果与目标图像的相似程度方面更佳,符合医学CT图像检索的要求。 相似文献
84.
Wang MM 《The international journal of biochemistry & cell biology》2011,43(11):1550-1562
Originally discovered nearly a century ago, the Notch signaling pathway is critical for virtually all developmental programs and modulates an astounding variety of pathogenic processes. The DSL (Delta, Serrate, LAG-2 family) proteins have long been considered canonical activators of the core Notch pathway. More recently, a wide and expanding network of non-canonical extracellular factors has also been shown to modulate Notch signaling, conferring newly appreciated complexity to this evolutionarily conserved signal transduction system. Here, I review current concepts in Notch signaling, with a focus on work from the last decade elucidating novel extracellular proteins that up- or down-regulate signal potency. 相似文献
85.
目的:总结肾综合征出血热(EHF)胸部并发症的CT表现和探讨胸部CT表现对肾综合征出血热的诊断价值。方法:分析60例经HFRS-IgM阳性确诊的HFRS的胸部螺旋cT表现,其中轻型5例、中型20例、重型28例、危重型7例。结果:肺部感染22例,肺水肿12例,胸腔积液4l例,心包积液17例,其中,心包积液合并肺水肿者4例,肺部感染并胸腔积液者4例,胸腔积液合并下肺局部膨胀不全18例,胸部CT检查正常8例。结论:肾综舍征出血热,胸部并发症发生几率较高,以胸腔积液及胸腔积液并下肺膨胀不全发生几率最高,HFRS的胸部CT表现对于临床有很好的治疗意义,早期CT检查可准确显示肾综合征出血热病人胸部改变的特征。 相似文献
86.
目的:探讨低剂量CT扫描在下肢动脉脉阻塞性病变诊断中的应用价值.方法:选择127段经DSA确诊的不同部位下肢动脉阻塞性病变行低剂量CT扫描,并采用MPR,VR,MIP等重建方法获得各下肢动脉CTA图像,将CTA图像与DSA图像的诊断结果利用统计学软件SAS8.1行加权Kappa一致性检验,检验水准为:Kaapa.系数大于0.75.结果:所得CTA图像与DSA图像诊断结果的一致性检验的kappa系数为0.8058,两种诊断结果的一致性为优.结论:采用低剂量扫描条件获得高质量的CTA图像在下肢动脉阻塞性病变的诊断上有肯定的价值. 相似文献
87.
Nanosecond dynamics of a mimicked membrane-water interface observed by time-resolved stokes shift of LAURDAN 下载免费PDF全文
We studied the dipolar relaxation of the surfactant-water interface in reverse micelles of AOT-water in isooctane in the nanosecond and subnanosecond time ranges by incorporating the amphipathic solvatochromic fluorescent probes LAURDAN and TOE. A negative component was observed in the fluorescence decays in the red edge of the emission spectrum-the signature of an excited state reaction-with LAURDAN but not for TOE. The deconvolution of the transient reconstructed spectra of LAURDAN based on a model constructed by adding together three log-normal Gaussian equations made it possible to separate the specific dynamic solvent response from the intramolecular excited state reactions of the probe. The deconvoluted spectrum of lowest energy displayed the largest Stokes shift. This spectral shift was described by unimodal kinetics on the nanosecond timescale, whereas the relaxation kinetics of water-soluble probes have been reported to be biphasic (on the subnanosecond and nanosecond timescales) due to the heterogeneous distribution of these probes in the water pool. Most of this spectral shift probably resulted from water relaxation as it was highly sensitive to the water to surfactant molar ratio (w(0)) (60-65 nm at w(0) = 20-30). A small part of this spectral shift (9 nm at w(0) = 0) probably resulted from dipolar interaction with the AOT polar headgroup. The measured relaxation time values were in the range of the rotational motion of the AOT polar headgroup region as assessed by LAURDAN and TOE fluorescence anisotropy decays. 相似文献
88.
The maturation of Borna disease virus (BDV) glycoprotein GP was studied in regard to intracellular compartmentalization, compartmentalization signal-domains, proteolytic processing, and packaging into virus particles. Our data show that BDV-GP is (i) predominantly located in the endoplasmic reticulum (ER), (ii) partially exists in the ER already as cleaved subunits GP-N and GP-C, (iii) is directed to the ER/cis-Golgi region by its transmembrane and/or cytoplasmic domains in CD8-BDV-GP hybrid constructs and (iv) is incorporated in the virus particles as authentic BDV glycoprotein exclusively in the cleaved form decorated with N-glycans of the complex type. Downregulation of BDV-glycoproteins on the cell surface, their limited proteolytic processing, and protection of antigenic epitopes on the viral glycoproteins by host-identical N-glycans are different strategies for persistent virus infections. 相似文献
89.
Amphiphilic beta-sheet cobra cardiotoxin targets mitochondria and disrupts its network 总被引:2,自引:0,他引:2
Recent advance in understanding the role of toxin proteins in controlling cell death has revealed that pro-apoptotic viral proteins targeting mitochondria contain amphiphilic alpha-helices with pore-forming properties. Herein, we describe that the pore-forming amphiphilic beta-sheet cardiotoxins (or cytotoxins, CTXs) from Taiwan cobra (Naja atra) also target mitochondrial membrane after internalization and act synergistically with CTX-induced cytosolic calcium increase to disrupt mitochondria network. It is suggested that CTX-induced fragmentation of mitochondria play a role in controlling CTX-induced necrosis of myocytes and cause severe tissue necrosis in the victims. 相似文献
90.
The complexes of horse myoglobin (Mb) with the anionic surfactant sodium dodecyl sulfate (SDS), and with the cationic surfactants cetyltrimethylammonium chloride (CTAC) and decyltrimethylammonium bromide (DeTAB), have been studied by a combination of surface tension measurements and optical spectroscopy, including heme absorption and aromatic amino acid fluorescence. SDS interacts in a monomeric form with Mb, which suggests the existence of a specific binding site for SDS, and induces the formation of a hexacoordinated Mb heme, possibly involving the distal histidine. Fluorescence spectra display an increase of tryptophan emission. Both effects point to an increased protein flexibility. SDS micelles induce both the appearance of two more heme species, one of which has the features of free heme, and protein unfolding. Mb/CTAC complexes display a very different behavior. CTAC monomers have no effect on the absorption spectra, and only a slight effect on the fluorescence spectra, whereas the formation of CTAC aggregates on the protein strongly affects both absorption and fluorescence. Mb/DeTAB complexes behave in a very similar way as Mb/CTAC complexes. The surface activity of the different Mb/surfactant complexes, as well as the interactions between the surfactants and Mb, are discussed on the basis of their structural properties. 相似文献