Sequence of the open reading frame of the FL01 gene from Saccharomyces cerevisiae

The cloned part of the flocculation gene FLO1 of Saccharomyces cerevisiae (Teunissen, A.W.R.H., van den Berg, J.A. and Steensma, H.Y. (1993). Physical localization of the flocculation gene FLO1 on chromosome I of Saccharomyces cerevisiae, Yeast, in press) has been sequenced. The sequence contains a large open reading frame of 2685 bp. The amino acid sequence of the putative protein reveals a serine- and threonine-rich C-terminus (46%), the presence of repeated sequences and a possible secretion signal at the N-terminus. Although the sequence is not complete (we assume the missing fragment consists of repeat units), these data strongly suggest that the protein is located in the cell wall, and thus may be directly involved in the flocculation process.     

The Dimerization of Oleic Acid with a Montmorillonite Catalyst I: Important Process Parameters; Some Main Reactions

Some important process parameters, e. g. amount of catalyst, water content, stirring intensity, reaction time and pH of the catalyst were studied in the dimerization of oleic acid using montmorillonite as catalyst. A yield limit seems to exist at about 60 wt% (dimers and trimers). The remaining 40 wt% of the reaction mixture (monomers) contain only small amounts of cis- and trans-mono-unsaturated fatty acids, the rest of it being unidentified products, which can hardly be dimerized and can not be hydrogenated with palladium on carbon. Infrared spectra of these monomers reveal also the presence of small amounts of γ-stearolactone and an increase in the number of methyl groups, which is probably the result of skeletal isomerization, although structures like -CH = C (CH₃)- are absent. The results indicate that a fairly large amount of saturated fatty acids is formed, most likely by hydrogen transfer. According to this assumption, dienoic acids must also be formed, which are readily dimerized to cyclic dimers. Thus the common assumption that the dimers of oleic acid obtained by this process are non-cyclic, becomes improbable.     

Diffusion of microspheres in sealed and open microarrays

In several experiments, we study the diffusion of microspheres with different radii in microarrays filled with a variety of aqueous solutions of ethylene glycol. We study diffusion in open and closed (sealed) microarrays. In sealed nanoliter wells, the tracers show pure diffusion, whereas in open reactors, a radial outward-directed evaporation-induced liquid flow is superimposed onto the diffusion. In general, one of the following quantities can be calculated if the others are known: the temperature, the viscosity of the medium, the radius of the microbeads, or the diffusion constant. The estimated diffusion constants in closed microarrays are in good agreement with theoretical predictions based on the Brownian motion. We monitor the motion of the microbeads under a microscope and extract their paths in time from the digital recordings. Ambiguous paths due to the crossing of two trajectories can be detected. We show that low microsphere concentrations or high viscosities do not hamper a robust estimation of the diffusion parameters.     

Recontamination as a source of pathogens in processed foods

Food products that have been submitted to an adequate heat-treatment during processing are free of vegetative pathogens and, depending on the treatments, of sporeformers and are generally regarded as safe. Processed products such as paté, ice cream, infant formulae and others have nevertheless been responsible for food-borne illnesses. Thorough epidemiological investigations of several of these outbreaks have demonstrated that the presence of vegetative pathogens such as Salmonella spp. or Listeria monocytogenes in the consumed products was frequently due to post-process recontamination. The majority of studies on pathogens in foods are devoted to investigations on their presence in raw materials or on their growth and behaviour in the finished products. Reference to recontamination is, however, only made in relatively few publications and very little is published on the sources and routes of these pathogens into products after the final lethal processing step. The investigation of an outbreak, including epidemiological studies and typing of strains, is very useful to trace the origin and source of the hazard. Published data demonstrate that the presence of pathogens in the vicinity of unprotected product in processing lines represents a significant risk of recontamination. Microbiological Risk Assessment studies can be conducted as part of governmental activities determining appropriate protection levels for populations. Although recontamination has been identified as a relevant cause of food incidences, it is often not considered in such studies. This paper advocates that an effort should be made to develop our knowledge and information on recontamination further and start using it systematically in the exposure assessment part of Microbiological Risk Assessment studies.     

液压系统发热的原因及预防措施

液压系统油温过高会使油液粘度降低，导致系统泄漏、效率降低、工作不稳定，并对液压元器件造成危害。本文阐述了液压系统发热的主要原因和预防措施。     

人脸检测技术的研究现状与展望

人脸检测是人脸识别系统中的关键的第一步,也是计算机视觉和模式识别研究领域的热点.本文首先对目前人脸检测技术的现状进行了分析比较,最后,提出了关于人脸检测技术的进一步发展方向.     

张峰水库输水二干末端调蓄水池坝体填筑碾压试验成果分析

针对张峰水库输水线路末端蓄水池填筑设计标准,通过现场碾压试验过程及成果分析,确定施工参数为坝体填筑提供施工依据。     

Investigation of Brazing Structure of Bulk Graphite to a W-Re Substrate

The brazing structure of bulk graphite to a W-Re substrate has been investigated in the present paper. The brazing specimens used were a W-15Re substrate with a sintered density of 17.97g/cm³, and bulk graphite with a density of 1.86g/cm³. Titanium foil with a thickness of 0.05–1.5mm was used as the brazing agent. W-Re substrate and bulk graphite were brazed in a vacuum furnace. After brazing, the phase composition and structure of brazed layer were analyzed. The test results show that W-Re substrate and bulk graphite can be joined together when titanium was used as the brazing agent. Titanium and graphite react and form TiC, which has a higher melting point during brazing. The phase compositions of the brazed layer were a W-Re solid solution, TiC, and residual carbon. The metallographic structure of the brazed layer was made up of a W-Re solid solution and TiC.     

Measuring Innovative Work Behaviour

Both scientists and practitioners emphasize the importance of innovative work behaviour (IWB) of individual employees for organizational success, but the measurement of IWB is still at an evolutionary stage. This article is concerned with developed a measure of IWB with four potential dimensions: the exploration, generation, championing and implementation of ideas. From a pilot survey among 81 research professionals and their supervisors, we derived an initial version of ten items. Next, analysis of validity drew on survey data from 703 matched dyads of knowledge workers and their supervisors in 94 knowledge intensive services firms. It included confirmatory factor analyses and hierarchical multilevel regressions to test hypothesized relationships of IWB with related constructs, including participative leadership, external work contacts and innovative output. These analyses demonstrated sufficient reliability and criterion validity. Evidence for the distinctiveness of the four dimensions was, however, weak, suggesting that IWB is one‐dimensional. We conclude that further research on this issue is merited.