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...     

有机酚醛聚合物凝胶深部调驱体系孔渗适应性研究

聚合物凝胶体系在地层中的渗流及封堵特性对深部调驱效果具有重要的影响。利用长填砂管驱替物模试验,研究了有机酚醛聚合物凝胶体系在不同渗透率填砂管中的注入特性、渗流行为和封堵性能,结果表明有机酚醛聚合物体系是一种注入性和流动性均较好的凝胶体系。通过对有机酚醛聚合物凝胶体系在长填砂管中的封堵特性和渗流参数结果分析,确定了有机酚醛聚合物凝胶体系组分质量浓度与3种地层渗透率的匹配关系。最后通过室内驱油物模试验,对凝胶体系与渗透率的匹配关系进行了验证。     

Reversal of advanced liver fibrosis in rabbits with Schistosomiasis japonica

Advanced liver fibrosis is generally considered to be irreversible. We studied the reversibility of marked liver fibrosis in rabbits infected with Schistosoma japonicum. We determined liver collagen content, collagen biosynthesis, and collagenase activity using serial biopsy specimens obtained 20, 40, and 60 weeks after infection. Reversibility of this process was investigated in rabbits cured of infection at 21 weeks; control rabbits not cured of infection were also studied. At 20 weeks, liver collagen content was 16-fold greater than normal, with accumulation of collagen types I, III, and V. Synthesis of collagen within fibrotic liver slices was 10-fold greater than normal. Liver collagenolytic activity for a type I substrate was 19-fold greater than normal. After parasitologic cure, a striking morphologic reversal of fibrosis occurred during the subsequent 40 weeks, with the return of liver collagen content to three-fold greater than normal and a 75% decrease in synthetic rates compared with those at 20 weeks (P < 0.01). Collagenolytic activity remained elevated to the same degree noted at 20 weeks. A similar but lesser resolution of fibrosis also occurred in untreated control rabbits, coincident with a spontaneous decrease in new egg deposition known to occur in this model system. We conclude that advanced liver fibrosis in S. japonicum-infected rabbits is slowly reversible after cure or senescence of the infection. A possible mechanism for this reversal is persistently increased collagenolysis as collagen synthesis diminishes.     

Hepatic artery ligation for liver metastasis of a acinar cell carcinoma of the pancreas revealed by a nodular panniculitis

We report the case of a 67-year-old-man presenting with pancreatic acinar cell carcinoma revealed by dermatological manifestations of cytosteatonecrosis and treated by hepatic artery ligation. The pancreatic etiology of these lesions was suspected due to hyperlipasemia, and was confirmed by abdominal computerized tomography showing a pancreatic tumor and multiple liver nodules, and by histological examination of one of these lesions. Because of symptomatic treatment failure, rapid impairment of patient's general condition, and by analogy with the treatment of hepatic metastases of neuroendocrine tumors, hepatic artery ligation was performed. Lipasemia decreased markedly and symptoms disappeared for 45 days. Hepatic artery obstruction may be used for emergency treatment of secreting liver metastases.     

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.