4,349 research outputs found
Thermodynamic evaluation of the Fe-Th system and glass forming ability in the Fe-Th system
A calculation of the Fe-Th phase relationships was undertaken in order to develop a self-consistent description of the system. A subregular solution model was used to describe the solution behavior. Intermediate phases were treated as composition invariant. Due to the limited availability of experimental thermodynamic data, a multi-step analysis was employed to develop a better description of the thermodynamic properties in the system;As a quantitative guide to the glass forming ability (GFA) in the Fe-Th system, T[subscript]0 and TTT curves were evaluated from the previously derived thermodynamic description of the system. From the TTT curves, critical cooling rates (R[subscript] c) to avoid crystallization were determined. Since the Fe-Th system has several solid phases, the relative stability of each phase in the metastable region is discussed. Kinetic parameters such as viscosity ([eta]), glass transition temperature (T[subscript] g) and interfacial energy ([sigma]) were estimated since experimental values were not available;This analysis indicates that thermodynamic data alone can not be relied upon to predict the phase boundary behavior. Both thermodynamic data and phase diagram data should be used
Surgical Management of Coexisting Coronary Artery and Valvular Heart Disease
Purpose: Combined coronary artery bypass (CAB) and valve surgery is one of the most challenging surgical procedures, but the operative results have improved over the years. Materials and Methods: From 1989 through 2004, combined CAB and valve operations were performed in 125 patients. Mean age was 63 years, and 86 patients were male. Forty-six patients were diagnosed with coronary artery disease during preoperative evaluation for valvular heart disease (VHD). All patients underwent CAB, and one or more underwent valve replacement or repair (mitral: 54, aortic: 61, tricuspid: 3, DVR: 7) simultaneously. Results: Mean number of distal graft was 1.98 ± 1.07, and LIMA was used in 68 % of patients. Early mortality occurred in 6 patients (4.8%), and the causes were heart failure (4) and sepsis (2). Mean follow-up duration was 91.4 ± 40.9 months (range: 47-245), and late mortality occurred in 4 patients. Kaplan Meier estimated survival rates at 1, 5, and 10 years were 94.4 %, 92.3%, and 89.9%, respectively. Conclusion: Combined coronary and valve operations can be performed safely with optimal surgical results. Although the surgical mortality of coexisting coronary and VHD is higher than either isolated coronary or valvular operations, it may not affect the long-term survival
Detection of an Ala601Thr mutation of plasminogen gene in 3 out of 36 Korean patients with deep vein thrombosis.
Plasminogen is a key proenzyme in the fibrinolytic and thrombolytic systems. Congenital deficiency of plasminogen and molecular abnormality of plasminogen (dysplasminogenemia) have been reported in association with the thrombotic tendency in human. In dysplasminogenemia, the level of immunoreactive plasminogen is normal, although the functional activity is reduced. Human plasminogen gene spans about 52.5 kb of DNA and consists of 19 exons. Three types of mutations (Ala601Thr, Val355Phe, and Asp676Asn) have been described in dysplasminogenemia. In this study, we measured the plasminogen activity in patients with deep vein thrombosis and analyzed the DNA sequence to detect three point mutations (Ala601Thr, Val355Phe and Asp676Asn) in patients with hypo/dysplasminogenemia. Dysplasminogenemia was identified in 3 (8.3%) of unrelated 36 patients with deep vein thrombosis and the Ala601Thr mutation was detected in all three patients with dysplasminogenemia. In conclusion, dysplasminogenemia is not rare in deep vein thrombosis, which suggests a risk factor for the thrombosis in Korean population
User Analysis Mechanisms based Mobile Fitness System
Modern men have health problems caused by lack of exercise than in the past. But most modern people do not know what to do exercise. Mobile systems for fitness to solve this problem have been developed. In this paper, by analyzing the user's BMI (Body Mass Index) Index and BMR (Basal Metabolic Rate) value, the data is made available. The processed data is provided to the user which proposes the right exercise and the appropriate level of exercise intensity, for exercise machines. This is different from detecting the movement, like the existing system, and a fitness value showing the calorie consumption caused. Thus the user is considered to be able to efficiently proceed to a movement based on the provided data
Regulation of endothelial nitric oxide synthase by agmatine after transient global cerebral ischemia in rat brain
Nitric oxide (NO) production by endothelial nitric oxide synthase (eNOS) plays a protective role in cerebral ischemia by maintaining vascular permeability, whereas NO derived from neuronal and inducible NOS is neurotoxic and can participate in neuronal damage occurring in ischemia. Matrix metalloproteinases (MMPs) are up-regulated by ischemic injury and degrade the basement membrane if brain vessels to promote cell death and tissue injury. We previously reported that agmatine, synthesized from L-arginine by arginine decarboxylase (ADC) which is expressed in endothelial cells, has shown a direct increased eNOS expression and decreased MMPs expression in bEnd3 cells. But, there are few reports about the regulation of eNOS by agmatine in ischemic animal model. In the present study, we examined the expression of eNOS and MMPs by agmatine treatment after transient global ischemia in vivo. Global ischemia was induced with four vessel occlusion (4-VO) and agmatine (100 mg/kg) was administered intraperitoneally at the onset of reperfusion. The animals were euthanized at 6 and 24 hours after global ischemia and prepared for other analysis. Global ischemia led severe neuronal damage in the rat hippocampus and cerebral cortex, but agmatine treatment protected neurons from ischemic injury. Moreover, the level and expression of eNOS was increased by agmatine treatment, whereas inducible NOS (iNOS) and MMP-9 protein expressions were decreased in the brain. These results suggest that agmatine protects microvessels in the brain by activation eNOS as well as reduces extracellular matrix degradation during the early phase of ischemic insult
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