Specific inhibitors of bacterial adhesion: observations from the study of gram-positive bacteria that initiate biofilm formation on the tooth surface

Oral surfaces are bathed in secretory antibodies and other salivary macromolecules that are potential inhibitors of specific microbial adhesion. Indigenous Gram-positive bacteria that colonize teeth, including viridans streptococci and actinomyces, may avoid inhibition of adhesion by host secretory molecules through various strategies that involve the structural design and binding properties of bacterial adhesins and receptors. Further studies to define the interactions of these molecules within the host environment may suggest novel approaches for the control of oral biofilm formation.     

Cutoff decomposition on multiply clad fibers

It is shown that the set of modal cutoffs of a multiply clad fiber is, under suitable conditions, given by combining the sets of modal cutoffs of two simpler fibers. The results have been derived analytically as well as by numerical methods.     

Identification of organic solvents by a virtual multisensor system with hierarchical classification

To improve the selectivity of semiconductor gas sensors, temperature modulation is often used. We present a study showing the potential of this technique with information gained comparable to multisensor systems. A dynamic operating mode coupled with a low-complexity evaluation strategy allows the identification of six organic solvent vapors over a wide concentration range (2-200 ppm) with a single sensor, for example, for leak detection systems. The system features low false alarm rates; in addition, interference by other gases, such as CO or NO/sub 2/, can be suppressed. For even higher identification power, switching on-line between different temperature cycles was studied, which provides better information for critical decisions.     

Fractal-based algorithmic design of Chinese ice-ray lattices

Chinese ice-ray lattices are perhaps one of the earliest and controlled designs of asymmetric and complex patterns applied as a traditional motif in windows. Such intricate and complex designs developed centuries back have created an evident curiosity to explore its underlying geometric rules. Some scholars used the Shape Grammar as a tool to explain and recreate similar patterns. The previous studies conceive the ice-ray lattice design as the iterative subdivisions of a polygon. However, they missed explaining this geometric quality through the discussion of fractal geometry, which can explain the shapes consuming self-similar or self-affine repetitions of itself at different scales. As a novel approach, this paper analytically focuses on the fractal characters of ice-ray lattice designs and uses fractal geometry as a unique tool for generating different types of ice-ray lattices. The significance of this study is the demonstration of the efficacy of fractal geometry and the simple geometric rule of IFS for analyzing and algorithmically modeling complex lattices and cracked-like patterns.     

The Impact of Psychic Distance on Chinese Outward Foreign Direct Investments

• The aim of this paper is to investigate the value of the well-known construct of psychic distance, developed to explain the internationalization path of firms from developed countries, for the internationalization of Chinese firms.
• Our research question is: Does psychic distance and its individual stimuli (differences in language, religion, culture, economic development, political systems, education, and geographic distance) explain Chinese investments abroad?
• We test hypotheses on the relation between psychic distance and its stimuli and Chinese outward direct investments with OLS regression analyses.
• We find that Chinese OFDI indeed is influenced by an aggregate construct of psychic distance and by certain psychic distance stimuli, but not by all; in particular, similarities or differences with regard to language and culture, the level of industrialization and the level of democracy relate to Chinese firms’ internationalization.
• Our findings suggest that psychic distance and its stimuli cannot be ignored as explanatory factors for Chinese outward FDI but that the explanatory value of these constructs depends on the context of the phenomenon under study.
• We conclude that it is important to understand how the home country context influences managerial perceptions and thereby patterns of international expansion from different regions.

     

L250Z系列柴油机的研制

在原6L250GZC－Ⅱ型柴油机的基础上，通过加长行程、改进增压系统、匹配先进的增压器、选择合适的平均有效压力和最高燃烧压力、改进燃油系统、提高燃油喷射压力、优化供油规律和喷油规律并选择合适的燃烧室，使燃油、空气在燃烧室中达到较理想的混合和燃烧，从而达到增加功率、降低油耗、改善排放、提而各项性能指标的要求。改进后的L2502系列柴油机在国内处于领先水平。     

强力甜味剂纽甜的合成研究

以异丁烯、乙烯和阿斯巴甜为原料,经加成、氧化和催化氢化等步骤合成了纽甜,总产率14.5%(以异丁烯计),产品的物理性质与波谱数据与文献一致。     

The Behavior of Precipitates during Hot-Deformation of Low-Manganese,Titanium-Added Pipeline Steels

The behavior of manganese and titanium sulfides during the hot deformation of a low-carbon, low-manganese, titanium-added steel has been studied using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive spectrometry (EDS) analysis. In addition, the effects of deformation temperature and strain rate on the size and distribution of precipitates have been studied using an automatic inclusion analysis system. Also, the effect of precipitate distribution on mechanical properties was studied at different deformation conditions of temperature and strain rate. The TEM and SEM analyses revealed the presence of a wide variety of simple and/or complex precipitates in the as-cast structure. These precipitates behaved differently during the hot deformation of steel. Precipitates deformed less at higher deformation temperatures, whereas an increase in strain rate increased the elongation of precipitates.     

Kinetics of the peritectic phase transformation: In-situ measurements and phase field modeling

An experimental study has been conducted into the role of cooling rate on the kinetics of the peritectic phase transformation in a Fe-C alloy. The interfacial growth velocities of the peritectic phase transformation were measured in situ for cooling rates of 100, 50, and 10 K/min. In-situ observations were obtained using high-temperature laser scanning confocal microscopy (HTLSCM) in a concentric solidification configuration. The experimentally measured interface velocities of the liquid/austenite (L/γ) and austenite/delta-ferrite (γ/δ) interphase boundaries were observed to increase with higher cooling rates. A unique finding of this study was that as the cooling rate increased, there was a transition point where the L/γ interface propagated at a higher velocity than the γ/δ interface, contrary to the findings of previous researchers. Phase field modeling was conducted using a commercial multicomponent, multiphase package. Good correlation was obtained between model predictions and experimental observations in absolute values of interface velocities and the effect of cooling rate. Analysis of the simulated microsegregation in front of the L/γ and γ/δ interfaces as a function of cooling rate revealed the importance of solute pileup. This microsegregation plays a pivotal role in the propagation of interfaces; thus, earlier modeling work in which complete diffusion in the liquid phase was assumed cannot fully describe the rate of propagation of the L/γ and δ/γ interfaces during the course of the peritectic transformation.