Leukotrienes in ulcerative colitis: results of a multicenter trial of a leukotriene biosynthesis inhibitor, MK-591

BACKGROUND & AIMS: Leukotrienes (LTs) are believed to be important in the pathogenesis of ulcerative colitis (UC). The aim of this study was to determine whether inhibition of LT biosynthesis with a 5-lipoxygenase inhibitor (MK-591) induces remission in patients with mild to moderate UC. METHODS: One hundred eighty-three patients with mild to moderately active UC enrolled in this randomized parallel group, double-blind study. Patients received placebo or MK-591 at a dose of 12.5, 50, or 100 mg twice daily for 8 weeks. A subset of patients underwent rectal dialysis to determine LTB4 concentration. RESULTS: MK-591 reduced LTB4 concentrations in rectal dialysate at the final determination. The median percent of baseline LTB4 concentration for 100 mg taken twice daily was 1.4% (n = 4); for 50 mg taken twice daily, 16.5% (n = 6); for 12.5 mg taken twice daily, 12% (n = 6); and for placebo, 78% (n = 6). There was no correlation between reduction of LTB4 and remission. Patients in remission at week 8 were as follows: placebo, 9 of 44 (20.5%); 100 mg taken twice daily, 11 of 43 (25.6%); 50 mg taken twice daily, 8 of 49 (16.3%); and 12.5 mg taken twice daily, 4 of 47 (8.5%) (P > 0.10). CONCLUSIONS: MK-591 markedly inhibited LT biosynthesis, but it did not differ significantly from placebo in clinical efficacy. Inhibition of LT biosynthesis was not effective as a single therapeutic modality in active UC.     

Ce,Nd和Y在α—Fe中的溶解度

用电子探针定量分析法测定了Ce、Nd和Y在873到1153K之间在α-Fe中的溶解度,从而获得溶解度与温度的关系式用x射线衍射法测定样品的点阵常数,用正电子湮没法测定Doppler线形参数S以及合金的矫顽力,用这三者与合金中稀土元素含量的关系确定稀土元素在α-Fe中溶解度的几个实验点。对上述电子探针测定的结果进行校核,其一致性令人十分满意     

Thermodynamic analysis of subcooling and superheating effects of alternative refrigerants for vapour compression refrigeration cycles

This paper presents a computer‐based first law and exergy analysis applied to vapour compression refrigeration systems for determining subcooling and superheating effects of environmentally safe new refrigerants. Three refrigerants are considered: R134a, R407c and R410a. It is found that subcooling and superheating temperatures directly influence the system performance as both condenser and evaporator temperatures are affected. The thermodynamic properties of the refrigerants are formulated using artificial neural network (ANN) methodology. Six ANNs were trained to predict various properties of the three refrigerants. The training and validation of the ANNs were performed with good accuracy. The correlation coefficient obtained when unknown data were used to the networks were found to be equal or very near to 1 which is very satisfactory. Additionally, the present methodology proved to be much better than the linear multiple regression analysis. From the analysis of the results it is found that condenser and evaporator temperatures have strong effects on coefficient of performance (COP) and system irreversibility. Also both subcooling and superheating affect the system performance. This effect is similar for R134a and R407c, and different for R410a. Copyright © 2005 John Wiley & Sons, Ltd.     

尾管悬挂器喇叭口清洗技术及应用

针对尾管固井碰压后悬挂器喇叭口残余水泥致使电测遇阻等问题，研制出了悬挂器剌叭口清洗装置。该装置与稀释分散水泥浆的ＦＮ清洗液配合使用，能避免尾管固井碰压后下钻通井清洗喇叭口作业，从而保证电测和采油等后续作业的顺利进行。辽河油田现场应用表明，该装置操作简便，性能可靠，效益显著     

J88型冷挤压机拉力肘杆机构的优化设计

本文在文献［１］基础上，对Ｊ８８型冷挤压机拉力肘杆机构的优化设计进行了全面的论述。     

Parameters controlling topical delivery of oligonucleotides by electroporation

Multiple 5-hydroxytryptamine (5-HT) receptors have been identified (5-HT1A/1B/1D/1E/1F, 5-HT2A/2B/2C, 5-HT3A/3B, 5-HT4A/4B, 5-HT5A/5B, 5-HT6 and 5-HT7A/7B/7C/7D) and extensive evidence suggests that 5-HT receptors have a role in learning and memory. Indeed, available evidence strongly supports physiological, pathophysiological and therapeutic roles of 5-HT systems in cognitive processes, although the evidence seems incomplete. Indeed, there has been a clear tendency to use pre-learning administration most frequently, whereas post-learning and pre-retention administration protocols have been utilized in only a few studies, and probably this trend has led to missed relevant information. For instance, when pre- vs post-training administration of 5-HT1A agonist, 5-HT2 antagonists and 5-HT4 agonists have been compared contrasting findings were reported in aversive and appetitive learning tasks. Emerging evidence also indicates that 5-HT1A and 5-HT4 receptor agonists, as well as, 5-HT1A antagonists, 5-HT2 antagonists, 5-HT3 antagonists and 5-HT uptake inhibitors may have therapeutic utility in the treatment of Alzheimer's disease and amnesia. Inasmuch as the activation or blockade of diverse 5-HT receptors is able to modulate cognitive processes, and 5-HT uptake inhibition could have therapeutic applications in the treatment of cognitive disorders, it seems evident that the role of 5-HT in learning and memory is more complex than a simple imbalance. Consequently, the notion that activation of the 5-HT systems impairs performance, whereas reduced serotonergic function may facilitate learning, must be reconsidered.     

再谈神木煤田资源的综合开发利用

神木煤及伴生资源的综合开发利用应遵循“能源转换与输出为主、建材和化工并举、分步式开发“的方针,近期先开发一些高耗能初级加工项目,逐步向深度加工利用的方向发展。选择坑口周边进行煤及伴生资源的综合开发利用,不仅可就地利用煤及其他资源,还可调动地方的积极性,有利于降低生产成本,获得显著的经济效益和整体效益。