Sphingomyelin breakdown and cell fate

A growing number of cell-surface receptors are now being shown to generate signals that trigger the hydrolysis of sphingomyelin to release diffusible ceramides. Ceramides have been implicated as key mediators in signaling pathways, with outcomes as diverse as cell proliferation, differentiation, growth arrest and apoptosis. The response depends on cell type, whether the signal is integrated with other signals originating from the same receptor and on the subcellular location of sphingomyelin hydrolysis and ceramide release.     

高压断路器的故障及其处理

本文主要论述了某公司高压断路器主要故障的产生原因及其处理措施.     

Myocardial glucose uptake and breakdown during adenosine-induced vasodilation

In isolated K+ (16.2 mM)-arrested cat hearts perfused at constant pressure adenosine infusions (0.8 mumoles - min-1 - 100 g-1 for 10 min) caused an increase in myocardial 14C-glucose uptake and release of 14CO2 + H14CO3- AND 14C-lactate simultaneously with a rise in coronary flow. The ratio of the release of 14CO2 + H14CO3- to that of 14C-lactate and the specific activity of lactate in the effuate were not altered. In K+ -arrested hearts perfused with constant volume neither glucose uptake nor glucose breakdown were influenced by 0.8 or 100 mumoles - min-1 - 100 g-1 adenosine with 0.1 - 5 mM glucose in the perfusion medium. It is concluded that adenosine does not affect directly the myocardial glucose carrier system, aerobic or anaerobic glucose breakdown or glycogenolysis, but enhances glucose uptake secondarily by increasing coronary flow. This interpretation is substantiated by the finding that mechanically produced increases in perfusion volume caused similar increases in myocardial glucose uptake as were observed with comparable adenosine-induced coronary flow increments.     

XD-685生化分析仪常见故障与保养

XD-685电解质分析仪具有操作简单、性能稳定、结果重复性好、仪器工作全部由电脑程序控制的优点,在国内已广泛使用.本科将该分析仪应用于临床检验并参加全省质量控制,钾离子、钠离子、氯离子、钙离子成绩均为"优",这与日常良好的保养与维护是密切相关的.科学的仪器保养及有效地排除故障,不但能延长仪器的使用寿命,而且不影响日常工作,我科于十年前购置了一台上海迅达医疗仪器有限公司生产的XD-685电解质分析仪,下面将十年来的常见故障及维护经验作一介绍,供参考.     

Skin breakdown in children and high-frequency oscillatory ventilation

OBJECTIVE: To investigate the relationship of high-frequency oscillatory ventilation (HFOV) to skin breakdown on the scalp and ears in mechanically ventilated children. STUDY DESIGN: Retrospective cohort study of 32 patients supported with HFOV paired with 32 patients supported with conventional mechanical ventilation (CV) in a pediatric intensive care unit (PICU). RESULTS: By univariate analysis, more HFOV patients had skin breakdown than did the CV patients (53% vs 12.5%, p=.001); HFOV patients also had greater severity of illness (Pediatric Risk of Mortality scores), higher mortality, and longer durations of neuromuscular blockade, low systolic blood pressure, and time exposed to risk. Life table analysis demonstrated no difference in the rate of skin breakdown between HFOV and CV patients. Multifactorial analysis showed that only PICU time at risk was a risk factor for skin breakdown. CONCLUSIONS: HFOV was not an independent risk factor for the development of skin breakdown. PICU time at risk was the sole risk factor for the development of skin breakdown in all mechanically ventilated patients in the PICU.     

带式输送机常见故障的分析与处理方法

带式输送机作为连续散状物料运输机械，以其输送量大、结构简单、维护方便、成本低、通用性强等优点，广泛应用在冶金、煤炭、交通、水电等部门。本文从实际各种现象入手，分析带式输送机常见故障的原因及处理方法。