一种基于时钟差的双端数据同步方法

文章对已有的双端数据采样同步方法进行了对比分析并指出了其优缺点.随着自愈环网和可变路由的光纤通道在高压电网中的普遍应用,采样数字同步网络复用通道作为传输信道时有可能出现通信路由不一致的情况,为了解决收、发通道延时不一致时的数据同步问题,文章引入装置“时钟差”的概念,以传统的“乒乓对时”为主,辅助以电气量对时,可以解决由...     

Idiopathic perforation of a porcine aortic bioprosthesis in the aortic position

The report of a failure of glutaraldehyde-preserved porcine aortic xenograft bioprosthesis in the aortic position after 13 months is presented. Severe aortic regurgitation resulted from three "idiopathic" perforations in one of the cusps, and a linear tear in another cusp. Light and electron microscopy showed generalized degeneration of collagen thoughout the faulty valve. The absence of a platelet-fibrin coat on edges of the tear suggested a recent origin, compatible with cardiac catheter manipulation during unsuccessful attempts to cross the valve. The histopathologic data from this valve correlate with previously reported failures with formaldehyde preserved xenograft valves.     

Treatment refractory schizophrenia: how should we proceed?

A substantial portion of schizophrenic patients demonstrate suboptimal response to conventional antipsychotics. These agents are primarily effective in the treatment of psychotic symptoms; their efficacy in other domains of psychopathology such as negative symptoms, chronic aggressive behavior, and cognitive deficits, is limited or non-existent. In this group of refractory patients, the novel atypical antipsychotic clozapine has demonstrated robust efficacy, with response rates approaching 60% after twelve weeks of treatment. Efficacy of clozapine extends to symptom domains other than psychosis, including negative symptoms, mood stabilization, aggressive behavior and compulsive water drinking. Several novel agents, each of which shares some, but not all, of the preclinical and clinical characteristics that make clozapine so unique, have been introduced in the last 4 years. These agents demonstrate a broader spectrum of efficacy and an improved side effect profile in non-refractory patients. Initial data on their efficacy in refractory patients suggests that olanzapine does not achieve overall superior efficacy in this patient population compared to conventional agents although there is some evidence of relatively greater efficacy in negative symptoms and aggressivity. Several studies suggest that the efficacy of risperidone is superior to that of conventional agents in refractory patients. Preliminary conclusions are not possible for quetiapine because of a paucity of data in the literature. The literature supports a risperidone trial prior to a clozapine trial in a treatment algorithm for refractory patients because of its more favorable risk/benefit profile.     

Genital herpes complicating pregnancy

The seroprevalence of herpes simplex virus type 2 (HSV-2) infections among reproductive-aged women in the United States in prevalent. This article discusses HSV and how it effects the pregnant women and neonates. Management of the disease is reviewed, and recommendations for management of HSV during pregnancy are given.     

Thermal evolution of trapped gas from extended subsurface layers during a linear tempering schedule

Numerical computer calculations for the thermal evolution of gas trapped by defects in extended subsurface layers of solids or coatings under a linear tampering schedule have been carried out. The dependence of the shape and location of thermal evolution transients upon the extension (width) of the initially trapped gas distribution has been found in comparison with the case of an initial planar concentration of trapped gas some lattice units below the surface. A comparative study has been performed concerning the effect of the thermal release mechanism (for ‘tandem’ and pure diffuisve mechanism) upon the thermal evolution transients having a given initial extended distribution and specific ratios of the migration energy to detrapping energy.     

Endothelin-1 is a paracrine growth factor that modulates melanogenesis of human melanocytes and participates in their responses to ultraviolet radiation

Endothelin (ET)-1, alpha-melanocyte stimulating hormone (alpha-melanotropin; alpha-MSH), and basic fibroblast growth factor (bFGF) are keratinocyte-derived factors that interact synergistically to stimulate human melanocyte proliferation. ET-1 has a dose-dependent mitogenic effect on human melanocytes and a biphasic effect on melanogenesis: a stimulatory effect at subnanomolar concentrations, and an inhibitory effect at concentrations equal to or higher than 1 nM. Human melanocytes express ET B receptors. Brief treatment of melanocytes with ET-1 caused up-regulation of alpha-MSH receptor mRNA but did not alter ET B receptor mRNA level. ET-1 modulates the response of human melanocytes to UV rays (UVRs). Treatment of melanocytes with 10 nM ET-1 immediately after exposure to UVRs enabled them to overcome the G1 growth arrest. However, ET-1 did not inhibit p53 accumulation or p21(Waf-1/SDI-1/Cip-1) overexpression, nor did it reverse the hypophosphorylated state of pRb or the reduction in Bcl2 level in irradiated melanocytes. These results substantiate the role of ET-1 as a paracrine regulator that modulates the response of human melanocytes to UVRs.     

A randomized comparison of dilatation alone versus dilatation plus laser in patients receiving chemotherapy and external beam radiation for esophageal carcinoma

Most patients with carcinoma of the esophagus have advanced disease at presentation. Since cure is usually not possible, the goal of treatment is the palliation of dysphagia. Palliative modalities include bougies, balloons, stents, tumor probe, laser, surgery, chemotherapy, and radiation. In recent years, combined chemotherapy and radiation has shown promising results. However, the relief of dysphagia is slow and frequently incomplete. We compared the effectiveness of dilatation alone versus dilatation plus Nd-YAG laser therapy for the relief of dysphagia while assessing the role of chemotherapy and radiation as an adjunct to surgery. Fifteen patients with squamous cell carcinoma of esophagus who were deemed fit for intensive chemotherapy and radiation were randomized to receive either dilatation alone (N = 7) or dilatation plus laser (N = 8); the end-point for initial success was the passage of a 45 French Savary dilator, and the relief of dysphagia. At entry, 13 of these 15 patients were judged potentially resectable. However, after chemotherapy and radiation, only 3 of 13 (20%) patients could be offered surgery; the remainder were considered too poor a surgical risk. Follow-up was for 30 months, or until death. Further dilatations were performed as needed for relief of dysphagia. No difference was observed between the laser plus dilatation and the dilatation alone group with respect to the degree of dysphagia, weight record, quality of life index (Karnofsky score), or mortality rate. Our results indicate that in patients undergoing chemotherapy and radiation for esophageal carcinoma, dilatation alone provides adequate palliation of dysphagia, and in these patients, chemotherapy and radiation is a poor adjunct to surgical treatment.     

Modification of unit responses to gustatory stimuli by conditioned taste aversion in rats

Secretion of trypsin, chymotrypsin, lipase and amylase was measured in male rats under urethane anaesthesia using a method of continuous perfusion of the duodenum. Prolonged infusion of cholecystokinin-pancreozymin (CCK-PZ) over a period lasting 200-360 min was administered either alone or together with a submaximal dose of secretin (1 unit/100 g - 10 min). Infusion of CCK-PZ was carried out using maximal doses (1--1.5 unit/100 g - 10 min) with and without secretin. Supramaximal doses of CCK-PZ (2 and 4 units/100 g - 10 min) were used only in combination with secretin. In all experiments secretion of enzymes showed a triphasic pattern including an initial peak followed by a plateau secretion after 10--20 min (phase 1), a decreasing second phase and finally base-line secretion (phase 3), thus demonstrating exhaustion of enzyme output from the gland with time. With increasing and supramaximal dose of CCK-PZ the cumulative output of enzymes from start to baseline secretion decreased progressively. Under the same conditions the levels of peak and plateau secretion were lower, the duration of plateau secretion was longer and the decreasing phase of secretion was shortened. These features indicate inhibition of secretion with increasing supramaximal doses of CCK-PZ infusion. Whereas the proteolytic enzymes and lipase reacted in a parallel way always amylase secretion was sustained on a higher level, implicating an alternative pathway for secretion.