Matrix unit cell scheduler (MUCS) for input-buffered ATM switches

This paper presents a novel matrix unit cell scheduler (MUCS) for input-buffered asynchronous transfer mode (ATM) switches. The MUCS concept originates from a heuristic strategy that leads to an optimal solution for cell scheduling. Numerical analysis indicates that input-buffered ATM switches scheduled by MUCS can utilize nearly 100% of the available link bandwidth. A transistor-level MUCS circuit has been designed and verified using HSPICE. The circuit features a regular structure, minimal interconnects, and a low transistor count. HSPICE simulation indicates that using 2-μm CMOS technology, the MUCS circuit can operate at clock frequency of 100 MHz     

Cervicovaginal foetal fibronectin in the prediction of preterm labour in a low-risk population

Ten groups of 14 immunosuppressed NMRI-mice (nu/nu) were raised and kept under germ-reduced conditions. The control animals were fed a germ-reduced diet, nine other groups received the same diet with selegiline (CAS 14611-51-9, Deprenyl) or lipoic acid (thioctic acid, CAS 62-46-4) admixed at various amounts. The 50% survival rate, the total life span of each group and the areas under the curves were determined to evaluate life expectancy as compared to the controls. The racemate of lipoic acid at high dosage (350 mg/kg body weight) reduced the life span significantly. The S(-)-enantiomer of lipoic acid (75 mg/kg body weight) increased the 50% survival rate, whereas the physiologic R(+)-enantiomer (9 mg/kg body weight) expanded the total life span of its group. Alteration of only one out of three parameters was not considered significant. All other groups except for one did not differ from controls: only animals which obtained 75 micrograms selegiline per kg of body weight and per day exerted increased life expectancies by all three parameters. This group exhibited also in statistical evaluation a significantly (p < 0.05) prolongated survival time up to about 200% as compared to the control animals.     

Isolation of a genetic locus associated with metronidazole resistance in Helicobacter pylori

We examined the molecular mechanism of metronidazole resistance by constructing a lambda-Zap II phagemid expression library with genomic DNA from a metronidazole-resistance strain of Helicobacter pylori. Twenty-two clones were found to have elevated MTZ resistances in XLOLR strain of E. coli. Phagemids belonging to the twenty two clones were extracted and then retransformed into the XLOLR strain of E. coli. After MTZ selection, five clones could confer metronidazole resistance consistently. According to Southern hybridization and DNA sequencing, the five clones contained a same locus, recA. In addition, transforming the five clones into BL21 strain of E. coli produced a higher resistance to MTZ. Interestingly, electroporation of one of the five phagemid clones into two MTZ sensitive H. pylori yielded MTZ resistant strains. Comparing amino acid sequence in MTZ resistant with sensitive isolates revealed two point mutations at this locus. Above results suggest that mutation in recA may be associated with metronidazole resistance of H. pylori.     

Synthesis and Hydrogen Storage in Single—walled Carbon Nanotubes

Single=walled carbon nanotubes(SWNTs) were synthesized by a hydrogen arc discharge method.A high yield of gram quantity of SWNTs per hour was achieved.Tow kinds of SWNT products:web-like substancea and thin films in large slices were obtained. Results of resonant Raman scattering measurements indicate that the SWNTs prepared have a wider diameter distribution and a larger mean diameter.Hydrogen uptake measurements of the two kinds of SWNT samples(both as prepared and pretreated) were carried out using a high pressure volumetric method,respectively.And a hydrogen storage capacity of 4 wt pct could be repeatedly achieved for the suitably pretreated SWMNTs,whicb indicates that SWNTs may be a promising hydrogen storge material.     

中国先进研究堆导流箱流场的数值模拟

采用目前国内普遍使用的计算流体力学 (CFD)软件PHOENICS 3 2对中国先进研究堆不同结构的导流箱的三维流场进行数值模拟计算。结果表明 :导流箱入口导流板和导流筒能显著改善导流箱入口冷却剂的流动状况 ,获得入口冷却剂沿周向均匀分流的效果 ,达到显著减缓入口冷却剂对垂直辐照孔道导管及安全棒导管直接的横向水力冲刷的设计目的     

Effects of beta-carotene and other factors on outcome of cervical dysplasia and human papillomavirus infection

OBJECTIVES: The age-dependence of the development of ventricular arrhythmias was studied in German shepherd dogs with inherited ventricular arrhythmias and sudden death. BACKGROUND: A colony of German shepherd dogs has been established that exhibit inherited ventricular arrhythmias and sudden death. The incidence of arrhythmias increases with age. Because ventricular tachycardia is associated with bradycardia, it was hypothesized that the increased incidence of arrhythmias was related to age-dependent slowing of heart rate. METHODS: Arrhythmia counts and RR intervals were measured from serial ambulatory ECG recordings obtained in 71 dogs (1-48 weeks). In addition, 19 dogs were challenged with phenylephrine (10 micrograms/kg i.v.) at 15, 28, and 45 weeks of age, 10 dogs were challenged with epinephrine (1 microgram/kg i.v.) at 3, 5, 7, 9, 11, 18, and 28 weeks of age, and 10 dogs were challenged at 28 weeks with epinephrine (2.5 micrograms/kg i.v.), before and after propranolol (0.5 mg/kg i.v.). RESULTS: The incidence and severity of ventricular arrhythmias increased between 7 and 28 weeks of age and decreased between 28 and 44 weeks of age. The age-dependent increase in the incidence of ventricular tachycardia was associated with age-dependent reductions in sinus rate. Baroreflex-mediated slowing of the heart rate unmasked arrhythmias in young animals that did not spontaneously display arrthythmias and exacerbated existing arrhythmias in older animals. However, the magnitude of baroreflex-induced bradycardia was similar from 7-18 weeks of age, yet the incidence of arrhythmias increased progressively. Moreover, the waning of ventricular arrhythmias in older animals was not associated with more rapid sinus rates. CONCLUSION: The risk for sudden death in dogs with inherited ventricular arrhythmias increases with age in part because of age-dependent slowing of heart rate and in part because of other heart-rate-independent factors. The correspondence between the development of ventricular tachycardia and sinus pauses is consistent with the hypothesis that ventricular arrhythmias are initiated by early afterdepolarization-induced triggered activity.     

Simulation of the pressure set-point change transient with the Kuosheng plant analyzer

The purpose of this paper is to simulate the pressure set-point change transient with the Kuosheng plant analyzer. The Kuosheng plant analyzer was developed for the Kuosheng nuclear power station based on the boiling water reactor plant analyzer of the Brookhaven National Laboratory and the Chinshan plant analyzer of the Taiwan Power Co. First, the pressure control system (PCS) model was verified on a stand-alone basis, with the sensed dome pressure test signal as the input variable. Then, a transient induced by a step change in the pressure set-point was simulated with the Kuosheng plant analyzer and compared with the test data. The predicted results of the main system variables showed good agreement with the test data-within 8% of the maximum relative deviation. In addition, the PCS performance of the Kuosheng nuclear power station was analyzed.     

珠江三角洲土坝和堤围震害初步预测

本项预测采用概率方法,即首先根据广东省水利部门提出的55座土坝和59个重点的座标(见附图),进行概率地震危险性分析,给出它们在一定预测年限T(取50年和100年)的地震烈度Ⅰ的超越概率;其次根据近年我国发生的几次强震时处于不同烈度区内的土坝和堤防的震害资料,形成表示土坝和土堤地震易损性的震害概率矩阵;然后,根据上述两方面结果用概率公式评价各土坝和堤围点在预测年限内各震害等级的超越概率,并取10％超越概率为标准,估计震害等级。结果表明,珠江三角洲土工构筑物的地震危害性南部高于北部。