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991.
A 36-year-old patient was investigated for a lifelong history of epistaxis and delayed bleeding after minor surgeries. Deficiencies or abnormalities of the coagulation system, of platelet function, or of factor XIII and alpha-2-antiplasmin were excluded. Consistently, however, over a period of 7 years, a high basal euglobulin fibrinolytic activity was observed that was characterized by a high tissue-type plasminogen activator (t-PA) activity, normal t-PA antigen, and undetectable plasminogen activator inhibitor type-1 (PAI-1) antigen and activity. The high specific activity of t-PA (640,000 IU/mg) and the minimal amounts of t-PA/PAI-1 complexes detected by fibrin zymography suggest that in this patient all t-PA was active. This is in striking contrast to normal plasma, where the majority of t-PA is complexed to PAI-1. Thus, in this patient, a severe deficiency of PAI-1 is associated with a delayed type bleeding tendency. Our observation underscores the importance of plasma PAI-1 for the stabilization of the hemostatic plug.  相似文献   
992.
The mechanisms underlying acute promyelocytic leukemia (APL) coagulopathy and its reversal by administration of all-trans retinoic acid (ATRA) have been investigated. Bone marrow promyelocytic blasts from nine patients with APL were cultured with or without ATRA 1 mumol/L. Cultured blasts (days 0, 3, 6, and 9) were washed, resuspended in phosphate buffer, lysed by freezing and thawing, and then assayed for procoagulant activity (PCA), elastase activity, tissue factor (TF) antigen, tissue-type plasminogen activator (t-PA) antigen and urokinase- type plasminogen activator (u-PA) antigen. PCA was determined by a recalcification assay. Elastase was measured by an amidolytic assay (S- 2484). TF, t-PA, and u-PA antigens were measured by an enzyme-linked immunosorbent assay (ELISA). Malignant promyelocytes isolated from the patients had increased levels of PCA and TF as compared with the control polymorphonucleates, and low levels of elastase, t-PA, and u- PA; the patient blast PCA level was significantly related to the degree of hypofibrinogenemia. In this system, blast PCA depended on the tissue factor and was significantly correlated to the TF antigen values. In the cultures without ATRA, PCA, TF, and u-PA progressively increased, whereas elastase and t-PA levels remained essentially unchanged. In the presence of ATRA, all parameters (except u-PA) decreased during the culture time. Thus, a major role of the promyelocytic blast cell PCA in the pathogenesis of M3-related coagulopathy is suggested; the ATRA effect on coagulopathy seems mainly mediated by a downregulation of the PCA.  相似文献   
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996.
Carbon nanofibers (CNFs) with excellent electrochemical performance represent a novel class of carbon nanostructures for boosting electrochemical applications, especially sustainable electrochemical energy conversion and storage applications. This work builds on an earlier study where the CNFs were prepared from a waste biomass (walnut shells) using a relatively simple procedure of liquefying the biomass, and electrospinning and carbonizing the fibrils. We further improved the mass ratio of the liquefying process and investigated the effects of the high temperature carbonization process at 1000, 1500 and 2000 °C, and comprehensively characterized the morphology, structural properties, and specific surface area of walnut shell-derived CNFs; and their electrochemical performance was also investigated as electrode materials in Li-ion batteries. Results demonstrated that the CNF anode obtained at 1000 °C exhibits a high specific capacity up to 271.7 mA h g−1 at 30 mA g−1, good rate capacity (131.3 and 102.2 mA h g−1 at 1 A g−1 and 2 A g−1, respectively), and excellent cycling performance (above 200 mA h g−1 specific capacity without any capacity decay after 200 cycles at 100 mA g−1). The present work demonstrates the great potential for converting low-cost biomass to high-value carbon materials for applications in energy storage.

Carbon nanofibers (CNFs) with excellent electrochemical performance represent a novel class of carbon nanostructures for boosting electrochemical applications, especially sustainable electrochemical energy conversion and storage applications.  相似文献   
997.
In order to mitigate the corrosion of steel rebar in concrete, a new environmentally friendly corrosion inhibitor formula (WKI) was designed and the corrosion inhibitive effects of WKI on steel rebar were studied by gravimetric method, electrochemical impendence spectroscopy (EIS), potentiodynamic polarization and Mott–Schottky scanning in simulated concrete pore solution. Furthermore, surface analysis and quantum chemical calculations were conducted in order to illustrate the corrosion inhibitive mechanism. The results indicate that WKI exhibits excellent corrosion inhibitive activities on steel rebar in simulated concrete pore solution. By the presence of WKI, local corrosion was significantly suppressed and no pitting could be detected during the whole experimental period. The total corrosion resistance was increased from 5469 Ω cm2 to 64 440 Ω cm2 and the corrosion current density was reduced from 3.23 μA cm−2 to 0.21 μA cm−2 for the sample immersed in the corrosion medium for 7 d with WKI. The corrosion potential of the steel rebar electrode moved to a higher level and the charge transfer resistance increased, indicating that the anti-corrosion properties of the steel rebar were enhanced. The corrosion inhibitive mechanism of WKI can be attributed to the fact that it can promote the formation of a passive film and reduce its defect concentration via its adsorption and interaction with the metal surface, consequently inhibiting the corrosion of steel rebar caused by chloride ions.

A new corrosion inhibitor formula was designed and the inhibitive mechanism was analyzed based on HSAB theory and the PDM model.  相似文献   
998.
目的探讨利用多反转空间标记脉冲非对比剂增强磁共振血管成像(non-contrast-enhanced magnetic resonance angiography using spatial labeling with multiple inversion pulses,SLEEK-MRA)评估门静脉血流动力学的可行性。材料与方法纳入25例门静脉高压患者先后行SLEEK-MRA和彩色多普勒超声(color doppler ultrasonograohy,CDUS)检查,SLEEK-MRA序列采用不同血流抑制反转时间(blood suppression inversion time,BSP TI):600、900、1200、1500 ms。对门静脉分支显示情况进行评级并与通过与CDUS血流速度测定结果进行相关性分析。依据CDUS所测流速将患者分组,并比较各组患者分支显示评级情况以及BSPTI参数应用情况。结果门静脉左、右支在全部BSPTI设定时SLEEK-MRA的分支显示评级均与CDUS所测得血流速度呈现出显著相关性。在门静脉流速明显减慢组患者,分支评级明显低于流速正常或轻度减慢组,应用BSP TI值明显高于流速正常或轻度减慢组。结论 SLEEK-MRA在提供高质量门静脉形态学成像同时,具有提示门静脉血流动力学变化的潜力,通过SLEEK-MRA获取血流动力学信息是可行的。  相似文献   
999.
Progressive supranuclear palsy (PSP) is a progressive neurodegenerative disorder caused by the deposition of abnormal proteins in neurons of the basal ganglia that limit motor ability, resulting in disability and reduced quality of life. So far, no pharmacologic therapy has been developed, and the treatment remains symptomatic. The aim of the present study is to perform a systematic investigation of the literature, and to determine the types and effects of rehabilitative interventions used for PSP. A search of all studies was conducted in MEDLINE/PubMed, the Cochrane Central Register of Controlled Trials, CINAHL, and EMBASE. Twelve studies were identified, including 6 case reports, 3 case series, one case-control study, one quasi?randomized trial (i.e. not truly random) with crossover design, and one randomized controlled trial, with 88 patients investigated overall. Rehabilitative interventions varied in type, number, frequency, and duration of sessions. The most commonly used clinical measures were the Progressive Supranuclear Palsy Rating Scale (PSPRS) and Unified Parkinson's Disease Rating Scale (UPDRS). Physical exercises were the main rehabilitative strategy but were associated with other interventions and rehabilitative devices, in particular treadmill and robot-assisted gait training. All studies showed an improvement in balance and gait impairment with a reduction of falls after rehabilitation treatment. Because of poor methodological quality and the variety of rehabilitative approaches including different and variable strategies, there was insufficient evidence of the effectiveness of any specific rehabilitation intervention in PSP. Despite this finding, rehabilitation might improve balance and gait, thereby reducing falls in PSP patients.

Level of Evidence

IV  相似文献   
1000.
Colloidal nanocrystals attract considerable attention in the field of light emitting devices thanks to their high fluorescence quantum yield, low amplified spontaneous emission (ASE) threshold, and spectral tunability via electronic structure engineering and surface functionalization. Combining polymer microcavities with colloidal nanocrystals as gain material promises a solution-based fabrication route to plastic laser cavities as well as applications in the field of smart flexible large area light sources and sensors. Here we demonstrate lasing from polymer microcavities embedding solution processable dot-in-rod (DiR) CdSe/CdS nanocrystals. Two highly reflective polymer dielectric mirrors are prepared by spin-coating of alternated layers of polyacrylic acid and poly(N-vinyl carbazole), with their photonic band gap tailored to the emission of the DiRs. The DiRs are enclosed in the polymer microcavity by drop-cast deposition on one mirror, followed by pressing the mirrors onto each other. We obtain excellent overlap of the ASE band of the DiRs with the photonic band gap of the cavity and observe optically pumped lasing at 640 nm with a threshold of about 50 μJ cm−2.

We report on the production of an optically pumped vertical cavity laser made by polymer mirrors embedding inorganic core@shell nanocrystals.  相似文献   
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