333 research outputs found

    Проект установки получения синтез-газа

    Get PDF
    ВКР 91 страницу, 6 рисунков, 40 таблиц, 24 литературных источника. Ключевые слова: синтез-газ, конверсия, применение синтез-газа, сырье, природный газ, технологическая схема, производство, метан, метанол. Объект разработки: производство синтез-газа методом паровой каталитической конверсии природного газа. Цель работы: изучение всех физико - химических свойств процесса и их влияния на протекание реакции, а также конструирование основного аппарата установки получения синтез - газа. В результате исследования выполнен расчет материального и теплового балансов, также конструктивный и механический расчеты, на основании которых был выполнен чертеж основного аппарата. ВКР выполнена на кафедре ТОВПМ ст. группы 2Д2А Якимовой В.А., под руководством к.х.н. Мананковой А.А.The final qualifying work contains 91 page, 6 figures, 40 tables and 24 literature sources. Content words are conversion, synthesis gas. The object of the development is the production of synthesis gas by catalytic steam reforming of natural gas. The mission is the study of physical - chemical properties of the process and their influence on the reaction, as well as the construction of the main unit installation producing synthesis - gas. The study was carried out payment of material and heat balances, the constructive and mechanical calculations, drawing on the basis of which the main unit was made. The final qualifying work carried out at the Department of TOVPM student group 2D2A Vera Yakimova, under the leadership of Candidate of Chemical Sciences Ann Manankova

    Small-volume resuscitation with hyperoncotic albumin: a systematic review of randomized clinical trials

    Get PDF
    Background Small-volume resuscitation can rapidly correct hypovolemia. Hyperoncotic albumin solutions, long in clinical use, are suitable for small-volume resuscitation; however, their clinical benefits remain uncertain. Methods Randomized clinical trials comparing hyperoncotic albumin with a control regimen for volume expansion were sought by multiple methods, including computer searches of bibliographic databases, perusal of reference lists, and manual searching. Major findings were qualitatively summarized. In addition, a quantitative meta-analysis was performed on available survival data. Results In all, 25 randomized clinical trials with a total of 1,485 patients were included. In surgery, hyperoncotic albumin preserved renal function and reduced intestinal edema compared with control fluids. In trauma and sepsis, cardiac index and oxygenation were higher after administration of hydroxyethyl starch than hyperoncotic albumin. Improved treatment response and renal function, shorter hospital stay and lower costs of care were reported in patients with liver disease receiving hyperoncotic albumin. Edema and morbidity were decreased in high-risk neonates after hyperoncotic albumin administration. Disability was reduced by therapy with hyperoncotic albumin in brain injury. There was no evidence of deleterious effects attributable to hyperoncotic albumin. Survival was unaffected by hyperoncotic albumin (pooled relative risk, 0.95; 95% confidence interval 0.78 to 1.17). Conclusion In some clinical indications, randomized trial evidence has suggested certain benefits of hyperoncotic albumin such as reductions in morbidity, renal impairment and edema. However, further clinical trials are needed, particularly in surgery, trauma and sepsis

    Serum heparan sulfate levels are elevated in endotoxemia

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Increased vascular permeability is a characteristic feature of sepsis which, in the past, has been ascribed exclusively to a malfunction of endothelial cells. However, recently it has become evident that the endothelial glycocalyx is of considerable importance concerning various aspects of vascular physiology, e.g. the vascular barrier and inflammation. Heparan sulfate, one of its essential components is characteristically traceable in blood, in case the endothelial glycocalyx is damaged or destroyed.</p> <p>Methods</p> <p>In 15 pigs we investigated whether the administration of endotoxin from gram-negative bacteria (Escherichia coli) results in increased serum levels of heparan sulfate, signalizing a shedding of the glycocalyx. In addition, markers of inflammation (white blood cell count, platelet count, tumour necrosis factor-α and interleukin-6) were evaluated over an observation period of 6 hours.</p> <p>Results</p> <p>Serum heparan sulfate concentrations significantly increased over time in the endotoxin group and were significantly elevated in comparison to the control group 6 hours after administration of endotoxin (p < 0.001). In the endotoxin group all markers of inflammation significantly changed during the time course.</p> <p>Conclusions</p> <p>The administration of bacterial endotoxin induced a significant rise in degradation products of the endothelial glycocalyx.</p

    Increased Serum Concentrations of Circulating Glycocalyx Components in HELLP Syndrome Compared to Healthy Pregnancy: An Observational Study

    Get PDF
    Severe inflammation has been shown to induce a shedding of the endothelial glycocalyx (EGX). Inflammatory cytokines, such as tumor necrosis factor alpha (TNF-alpha), impede the thickness of the EGX. While a controlled inflammatory reaction occurs already in normal pregnancy, women with hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome had an exaggerated inflammatory response. This study investigates the shedding of the glycocalyx during normal pregnancy and in women with HELLP syndrome. Glycocalyx components (syndecan 1, heparan sulfate, and hyaluronic acid) were measured in serum of healthy women throughout pregnancy (4 time points, n = 26), in women with HELLP syndrome (n = 17) before delivery and in nonpregnant volunteers (n = 10). Serum concentrations of TNF-alpha and soluble TNF-alpha receptors (sTNF-Rs) were assessed once in all 3 groups. Syndecan 1 serum concentrations constantly rose throughout normal pregnancy. Immediately before delivery, a 159-fold increase was measured compared to nonpregnant controls (P < .01). Even higher amounts were observed in patients with HELLP prior to delivery (median 12 252 ng/mL) compared to healthy women matched by gestational age (median 5943 ng/mL; P < .01). Relevantly, increased serum levels of heparan sulfate, hyaluronic acid, and sTNF-Rs were only detected in patients with HELLP (P < .01). These findings suggest that considerable amounts of syndecan 1 are released into maternal blood during uncomplicated pregnancy. The HELLP syndrome is associated with an even more pronounced shedding of glycocalyx components. The maternal vasculature as well as the placenta has to be discussed as a possible origin of circulating glycocalyx components

    Optimal Cerebral Perfusion Pressure During Delayed Cerebral Ischemia After Aneurysmal Subarachnoid Hemorrhage

    Get PDF
    OBJECTIVES: The recommendation of induced hypertension for delayed cerebral ischemia treatment after aneurysmal subarachnoid hemorrhage has been challenged recently and ideal pressure targets are missing. A new concept advocates an individual cerebral perfusion pressure where cerebral autoregulation functions best to ensure optimal global perfusion. We characterized optimal cerebral perfusion pressure at time of delayed cerebral ischemia and tested the conformity of induced hypertension with this target value. DESIGN: Retrospective analysis of prospectively collected data. SETTING: University hospital neurocritical care unit. PATIENTS: Thirty-nine aneurysmal subarachnoid hemorrhage patients with invasive neuromonitoring (20 with delayed cerebral ischemia, 19 without delayed cerebral ischemia). INTERVENTIONS: Induced hypertension greater than 180 mm Hg systolic blood pressure. MEASUREMENTS AND MAIN RESULTS: Changepoint analysis was used to calculate significant changes in cerebral perfusion pressure, optimal cerebral perfusion pressure, and the difference of cerebral perfusion pressure and optimal cerebral perfusion pressure 48 hours before delayed cerebral ischemia diagnosis. Optimal cerebral perfusion pressure increased 30 hours before the onset of delayed cerebral ischemia from 82.8 +/- 12.5 to 86.3 +/- 11.4 mm Hg (p < 0.05). Three hours before delayed cerebral ischemia, a changepoint was also found in the difference of cerebral perfusion pressure and optimal cerebral perfusion pressure (decrease from -0.2 +/- 11.2 to -7.7 +/- 7.6 mm Hg; p < 0.05) with a corresponding increase in pressure reactivity index (0.09 +/- 0.33 to 0.19 +/- 0.37; p < 0.05). Cerebral perfusion pressure at time of delayed cerebral ischemia was lower than in patients without delayed cerebral ischemia in a comparable time frame (cerebral perfusion pressure delayed cerebral ischemia 81.4 +/- 8.3 mm Hg, no delayed cerebral ischemia 90.4 +/- 10.5 mm Hg; p < 0.05). Inducing hypertension resulted in a cerebral perfusion pressure above optimal cerebral perfusion pressure (+12.4 +/- 8.3 mm Hg; p < 0.0001). Treatment response (improvement of delayed cerebral ischemia: induced hypertension(+) [n = 15] or progression of delayed cerebral ischemia: induced hypertension(-) [n = 5]) did not correlate to either absolute values of cerebral perfusion pressure or optimal cerebral perfusion pressure, nor the resulting difference (cerebral perfusion pressure [p = 0.69]; optimal cerebral perfusion pressure [p = 0.97]; and the difference of cerebral perfusion pressure and optimal cerebral perfusion pressure [p = 0.51]). CONCLUSIONS: At the time of delayed cerebral ischemia occurrence, there is a significant discrepancy between cerebral perfusion pressure and optimal cerebral perfusion pressure with worsening of autoregulation, implying inadequate but identifiable individual perfusion. Standardized induction of hypertension resulted in cerebral perfusion pressures that exceeded individual optimal cerebral perfusion pressure in delayed cerebral ischemia patients. The potential benefit of individual blood pressure management guided by autoregulation-based optimal cerebral perfusion pressure should be explored in future intervention studies

    Strengthening the morphological study of informal settlements

    Get PDF
    Methods of articulating the morphological structure of slums can have considerable potential in better planning for site-specific design or policy responses for these areas in the contemporary city. Although urban morphology traditionally studies landscapes as stratified residues with distinct divisions between lot and boundary, built and unbuilt, the authors find these definitions insufficient to address the complexity of slum morphology. Through this article, the authors’ identify that morphological analysis of informal settlements needs to be sensitive to the dynamics and the absence (or blurring) of physical boundaries. By analyzing the spatial impact of social, economic, and political factors, situational and site factors, building typologies, and configurations of circulation space, an attempt to articulate the morphological structure of slums is made. Aiming to overcome the current polarization in the literature between the formal and informal city, this article adds to the ongoing research on the study of challenges within contemporary cities, by providing new methodologies for studying the morphology of slum urbanization and shaping planning practice

    MR Imaging Radiomics Signatures for Predicting the Risk of Breast Cancer Recurrence as Given by Research Versions of MammaPrint, Oncotype DX, and PAM50 Gene Assays

    Get PDF
    To investigate relationships between computer-extracted breast magnetic resonance (MR) imaging phenotypes with multigene assays of MammaPrint, Oncotype DX, and PAM50 to assess the role of radiomics in evaluating the risk of breast cancer recurrence
    corecore