370 research outputs found

    NDE Positron Study of Cu And Cu-Al Alloys Thermally Charged with Hydrogen and Deformed

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    Some aspects of the deformation of Cu, Cu-2 w/o Al, and Cu-4 w/o Al alloy samples after thermal charging with hydrogen at 1000ºC and rapid quenching (to -150ºC isopentane) were treated in an earlier publication [1]. Comparisons were made with samples treated as just described except for use of an Ar atmosphere at 1000°C. The main experimental measurements then as now were of the Doppler broadening of the positron annihilation spectrum and the microhardness. The deformation was imposed by a Brinell indentation of 500 kgf

    Successful interdisciplinary management of the misdeployment of two self-expanding stents into the internal carotid artery: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>With the widespread use of carotid artery stenting, previously unknown technical mistakes of this treatment modality are now being encountered. There are multiple strategies for the treatment of in-stent restenosis. With regard to surgical management, endarterectomy and patch plasty are favored. To the best of our knowledge, this report is the first description of a complete stent removal by the eversion technique.</p> <p>Case presentation</p> <p>We report the case of a 63-year-old Caucasian man with misdeployment of two stents into his stenotic proximal internal carotid artery, resulting in a high-grade mechanical obstruction of the internal carotid artery lumen. With the contralateral internal carotid artery already occluded and associated stenoses of both proximal and distal vertebral arteries, an interdisciplinary therapeutic concept was applied. Bilateral balloon angioplasty and stenting of the proximal and distal stenotic vertebral arteries were carried out to provide sufficient posterior collateral blood flow, followed by successful surgical stentectomy and carotid endarterectomy using the eversion technique. Duplex scanning and neurological assessments were normal over a 12-month follow-up period.</p> <p>Conclusions</p> <p>Interdisciplinary treatment is a recommended option to protect patients from further impairment. Further evaluation in larger studies is highly recommended.</p

    Variation in amount of wild-type transthyretin in different fibril and tissue types in ATTR amyloidosis

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    Familial transthyretin (TTR) amyloidosis is caused by a mutation in the TTR gene, although wild-type (wt) TTR is also incorporated into the amyloid fibrils. Liver transplantation (LT) is the prevailing treatment of the disease and is performed in order to eliminate the mutant TTR from plasma. The outcome of the procedure is varied; especially problematic is a progressive cardiomyopathy seen in some patients, presumably caused by continued incorporation of wtTTR. What determines the discrepancy in outcome is not clear. We have previously shown that two structurally distinct amyloid fibrils (with or without fragmented ATTR) are found among ATTRV30M patients. In this study, we investigated the proportion of wtATTR in cardiac and adipose amyloid from patients having either fibril type. It was found that cardiac amyloid more easily incorporates wtTTR than adipose amyloid, offering a potential explanation for the vulnerability of cardiac tissue for continued amyloidosis after LT. In cardiac tissue, fibrils with fragmented ATTR contained a higher wt proportion than fibrils without, suggesting that continued incorporation of wtTTR after LT, perhaps, can take place more easily in these patients. In adipose tissue, a rapid increase in wt proportion after LT indicates that a rather fast turnover of the deposits must occur. A difference in wt proportion between the fibril types was seen post-LT but not pre-LT, possibly caused by differences in turnover rate. Conclusively, this study further establishes the basic dissimilarities between the two fibril types and demonstrates that their role in LT outcome needs to be further investigated

    Shaping bursting by electrical coupling and noise

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    Gap-junctional coupling is an important way of communication between neurons and other excitable cells. Strong electrical coupling synchronizes activity across cell ensembles. Surprisingly, in the presence of noise synchronous oscillations generated by an electrically coupled network may differ qualitatively from the oscillations produced by uncoupled individual cells forming the network. A prominent example of such behavior is the synchronized bursting in islets of Langerhans formed by pancreatic \beta-cells, which in isolation are known to exhibit irregular spiking. At the heart of this intriguing phenomenon lies denoising, a remarkable ability of electrical coupling to diminish the effects of noise acting on individual cells. In this paper, we derive quantitative estimates characterizing denoising in electrically coupled networks of conductance-based models of square wave bursting cells. Our analysis reveals the interplay of the intrinsic properties of the individual cells and network topology and their respective contributions to this important effect. In particular, we show that networks on graphs with large algebraic connectivity or small total effective resistance are better equipped for implementing denoising. As a by-product of the analysis of denoising, we analytically estimate the rate with which trajectories converge to the synchronization subspace and the stability of the latter to random perturbations. These estimates reveal the role of the network topology in synchronization. The analysis is complemented by numerical simulations of electrically coupled conductance-based networks. Taken together, these results explain the mechanisms underlying synchronization and denoising in an important class of biological models

    Consensus on circulatory shock and hemodynamic monitoring. Task force of the European Society of Intensive Care Medicine.

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    OBJECTIVE: Circulatory shock is a life-threatening syndrome resulting in multiorgan failure and a high mortality rate. The aim of this consensus is to provide support to the bedside clinician regarding the diagnosis, management and monitoring of shock. METHODS: The European Society of Intensive Care Medicine invited 12 experts to form a Task Force to update a previous consensus (Antonelli et al.: Intensive Care Med 33:575-590, 2007). The same five questions addressed in the earlier consensus were used as the outline for the literature search and review, with the aim of the Task Force to produce statements based on the available literature and evidence. These questions were: (1) What are the epidemiologic and pathophysiologic features of shock in the intensive care unit ? (2) Should we monitor preload and fluid responsiveness in shock ? (3) How and when should we monitor stroke volume or cardiac output in shock ? (4) What markers of the regional and microcirculation can be monitored, and how can cellular function be assessed in shock ? (5) What is the evidence for using hemodynamic monitoring to direct therapy in shock ? Four types of statements were used: definition, recommendation, best practice and statement of fact. RESULTS: Forty-four statements were made. The main new statements include: (1) statements on individualizing blood pressure targets; (2) statements on the assessment and prediction of fluid responsiveness; (3) statements on the use of echocardiography and hemodynamic monitoring. CONCLUSIONS: This consensus provides 44 statements that can be used at the bedside to diagnose, treat and monitor patients with shock

    Clinical presentation and predictors of outcome in patients with severe acute exacerbation of chronic obstructive pulmonary disease requiring admission to intensive care unit

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    BACKGROUND: Severe acute exacerbation of chronic obstructive pulmonary disease (AE-COPD) is a common reason for emergency room (ER) visit about which little has been documented from India. METHODS: Prospective study of the clinical presentation and predictors of outcome in 116 patients presenting with severe AE-COPD requiring admission to the medical intensive care unit between January 2000 and December 2004. RESULTS: Their mean age was 62.1 ± 9.8 years. There were 102 males. Mean duration of COPD was 7.2 ± 5.8 years. All males were smokers (22.3 ± 11.2 pack years); 35.2% smoked cigarettes and 64.8% smoked bidis. All women were exposed to domestic fuel. Associated co-morbid illnesses were present in 81 patients (69.8%); 53(45.7%) had one co-morbid illness and the remaining 28 (54.3%) had two or more co-morbid illnesses. Evidence of past pulmonary tuberculosis (PTB) was present in 28.4% patients; 5 patients who also had type II diabetes mellitus had active PTB. Arterial blood gas analysis revealed respiratory failure in 40 (33.8%) patients (type I 17.5% and type II 82.5%). Invasive mechanical ventilation was required in 18 patients. Sixteen (13.7%) patients died. Stepwise multivariate logistic regression analysis revealed need for invasive ventilation (OR 45.809, 95%CI 607.46 to 3.009;p < 0.001); presence of co-morbid illness (OR 0.126, 95%CI 0.428 to 0.037;p < 0.01) and hypercapnia (OR 0.114, 95%CI 1.324 to 0.010;p < 0.05) were predictors of death. CONCLUSION: Co-morbid conditions and metabolic abnormalities render the diagnosis of AE-COPD difficult and also contribute to mortality. High prevalence of past PTB and active PTB in patients with AE-COPD suggests an intriguing relationship between smoking, PTB and COPD which merits further study
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