Invasive group A streptococcal disease in Taiwan is not associated with the presence of streptococcal pyrogenic exotoxin genes

We reviewed the clinical features of 44 patients with invasive group A streptococcal (GAS) disease who were treated at two teaching hospitals in southern Taiwan from 1991 to 1994. Genes encoding streptococcal pyrogenic exotoxin types A (speA), B (speB), C (speC), and F (speF) and serotypes of M1, M6, and M12 were determined by polymerase chain reaction to target specific sequences in the 44 isolates recovered from these patients and in 28 isolates recovered from upper respiratory sites in 28 additional patients during the study period. The protease activity of these isolates was tested by using the casein plate method. Of the 44 patients with invasive diseases, 25 (57%) had no obvious underlying diseases, and 14 (32%) had preexisting neoplastic diseases or had previously used steroids. Twenty-five patients (57%) presented with cellulitis or necrotizing fasciitis, 24 (55%) had bacteremia, and eight (18%) had streptococcal toxic shock syndrome (STSS). Eight patients (18%) died of invasive GAS disease; seven had STSS, and seven had underlying diseases. All eight patients died within 48 hours after hospitalization. The presence of speA, speC, or speF was not implicated in any particular clinical syndrome in patients with invasive GAS disease. High-level protease activity and the M1 serotype of the isolates were significantly associated with the clinical signs of STSS and with mortality. M1 serotype and protease activity, as well as host immune status, might play significant roles in the pathogenesis of invasive GAS disease in Taiwan.     

Structural topology optimization using ant colony optimization algorithm

The ant colony optimization (ACO) algorithm, a relatively recent bio-inspired approach to solve combinatorial optimization problems mimicking the behavior of real ant colonies, is applied to problems of continuum structural topology design. An overview of the ACO algorithm is first described. A discretized topology design representation and the method for mapping ant's trail into this representation are then detailed. Subsequently, a modified ACO algorithm with elitist ants, niche strategy and memory of multiple colonies is illustrated. Several well-studied examples from structural topology optimization problems of minimum weight and minimum compliance are used to demonstrate its efficiency and versatility. The results indicate the effectiveness of the proposed algorithm and its ability to find families of multi-modal optimal design.     

An innovative framework of collaborative-based workflow in Development Chain Management

Currently, most product development procedures have been characterized as unnecessarily complicated. To maintain a competitive edge and to simplify the procedures, joint efforts from different functional groups play such crucial role. Specifically, information from marketing, sales, engineering, sourcing, and manufacturing should be cross-referenced. In addition, adopting pre-defined workflows contributes to efficient collection of distributed information. Moreover, unlike traditional workflow, a collaborative-based workflow (CWF) in product development process boasts of complicated workflow forms with manifold views for a workflow execution. Traditional workflow solutions, for instance, can only transmit a workflow form through different actors. Such workflow solutions merely offer modeling approval-based workflow (AWF), such as drawing reviews or absence applications.     

Chemical,biochemical, and biological significance of polyphenols in cereals and legumes

Polyphenols in cereals and legumes have been receiving considerable attention largely because of their adverse influence on color, flavor, and nutritional quality. These compounds belong to the flavonoid and tannin groups and are mostly located in the seed coat or pericarp of the grains. The pearl millet flavonoids have been identified as C‐glycosylflavones by the combined use of paper chromatography and UV spectroscopy. Although nontoxic, physiological and nutritional significance of these compounds occurring in high amounts in the pearl millet grain are still not clearly understood. In view of aesthetic quality, bleaching of the millet grains in acidic solution is recommended. A large proportion of current assays involves spectrophotometry of tannin or its chromogen and tannin‐protein interaction. Sorghum and legume tannins have been characterized as condensed tannins. Several factors such as plant type, age of the plant or plant parts, stage of development, and environmental conditions govern the polyphenol contents in plants. Polyphenols are known to interact with proteins and form tannin‐protein complexes leading to either inactivation of enzymes or making proteins insoluble. These are implicated in decreasing the activities of digestive enzymes, protein and amino acid availabilities, mineral uptake, vitamin metabolism, and depression of growth. Polyphenols are known to cause certain ultrastructural changes in the different parts of experimental animals. A correlation between dietary tannins and occurrence of esophageal cancer has been established. Bird resistance and seed germination in food crops have been correlated to high contents of polyphenols. The antinutritional activity of polyphenols can be reduced by removing polyphenols from the grains by chemical treatments or removing pericarp and testa by pearling. Treatment of alkaline reagents and ammonia can remove 90% of the polyphenols. Supplementation of polyphenols‐rich diet with protein can alleviate the growth‐depressing effect of polyphenols.     

Incremental Value Iteration for Time-Aggregated Markov-Decision Processes

A value iteration algorithm for time-aggregated Markov-decision processes (MDPs) is developed to solve problems with large state spaces. The algorithm is based on a novel approach which solves a time aggregated MDP by incrementally solving a set of standard MDPs. Therefore, the algorithm converges under the same assumption as standard value iteration. Such assumption is much weaker than that required by the existing time aggregated value iteration algorithm. The algorithms developed in this paper are also applicable to MDPs with fractional costs.     

Effects of impurities on removal of polysilicon in chemical-mechanical polish

The effects of impurities on the removal of doped polysilicon in the chemical-mechanical polishing (CMP) process is discussed. It has been found that the Si-CMP is seriously retarded in the presence of boron impurities. In this paper, effects of several usually used n-and p-type impurities for polysilicon are investigated. Successive polishing was performed to reveal the correlation between the removal rate and the dopant concentration along the depth of polysilicon layer. The removal is seriously retarded for p-type samples and slightly enhanced for n-type samples. After excluding the interference from surface roughness, linear relationship was found between the resultant removal rate and the doping concentration. In this study, electrostatic interaction between the reactant ions and the ionized impurities at the silicon surface is proposed to be the primary factor to change the removal reaction rates. For p-type polysilicon etched in an alkaline aqueous solution, transport of OH⁻ anions is hindered because OH⁻ anions experience a repelling force in front of the negative-charged acceptors. Following the same principle, the removal reaction forn-type polysilicon is enhanced. However, the removal rate forn-type polysilicon is rather limited by surface reaction than by transport of reactant ions. As a consequence, the enhancement of removing n-type polysilicon is not so prominent as compated to the retardation effect found for removal of p-type polysilicon.     

机器人双手协调运动中的误差分析及补偿

本文首次分析了机器人双手协调运动中的动态与控制误差,导出了误差矩阵方程,据此提出了补偿算法,实验验证了算法的有效性,由于本算法并不局限于某一特定类型的机器人,因而具有较普遍的意义。算法已应用于机器人双手协调运动的实时控制,文中并对误差引起的目标物体变形进行了讨论。