In vivo pharmacokinetic of amikacin and its pharmacodynamic in combination with cefepime, cefpirome and meropenem in an in vitro/ex vivo micropig model

Thirty patients with laryngeal tumors were divided into two groups on the basis of whether clinical and pathological features indicated good or bad prognosis. Samples of each tumor group were selected and examined by immunohistochemistry using mAbs, raised against integrin chains (beta 1, beta 4, alpha 2, alpha 3, alpha 6) and their ligands laminin 1 and 5, collagen type IV, two fibronectin isoforms (ED-A and ED-B) and two isoforms of tenascin known to be associated with neoplasm. Controls were provided by samples of tumor-free laryngeal mucosa removed during the surgical procedure. The normal topographical integrin pattern and the continuity of the basement membrane components was altered in both groups but the extent of these changes was significantly greater in those tumors with poor prognosis. Therefore, the groups could easily and reliably be distinguished by simply observing their immunohistochemical features. It is suggested that performing immunohistochemical analysis on biopsies may aid in early diagnosis as well as in adopting the proper therapeutic strategy to follow for these tumors. The above molecules may become one of the diagnostic tools available for head and neck surgical pathologists.     

Study of Dimethoxysilacycloalkanes as External Donors in Ziegler-Natta Stereospecific Propylene Polymerisation

Summary A series of cyclic dimethoxysilanes has been prepared using a one-step strategy which consists in reacting magnesium dibromoalkanes with tetramethoxysilane. The dimethoxysilacycloalkanes obtained were evaluated as the external electron donor in Ziegler–Natta catalysts for propylene polymerisation. Comparison of the experimental results with theoretical predictions using a molecular model confirmed the essential structural characteristics that are required to achieve stereospecific polymerisation of propylene. Very good activity and stereospecificity were obtained with 2,6-diethyl-1,1-dimethoxysilacyclohexane which led to results close to that of actual industrial external electron donors, cyclohexylmethyldimethoxysilane and dicyclopentyl dimethoxysilane.     

Synthèse vocale et handicap

A text to speech synthesis system receives as its input textual information and produces a speech signal as an output message. In the area of multimodal interfaces, problems concerning assistive communication for handicapped people requires implementation of various technologies using the “text to speech synthesis” block. This use of vocal synthesis is aimed at users with visual deficiencies or with cerebral palsy. In this article we describe the major technical advancse producing speech from text.     

Homology modelling of rat kallikrein rK9, a member of the tissue kallikrein family: implications for substrate specificity and inhibitor binding

The rat kallikrein rK9 is one of the six members of the rattissue kallikrein family isolated to date. It is 84% identicalto rK2 (tonin), and both proteinases are thought to have vasoconstrictiveproperties. Recently we have shown that rK9 and rK2 have distinctsubstrate specificities and sensitivities to inhibitors, despitetheir similar sequences. Unlike all other mammalian kallikrein-relatedproteinases, rK9 is resistant to inhibition by aprotinin. Wehave developed a 3-D model of rK9, based on the known X-raystructures of rK2, porcine kallikrein and bovine trypsin, toidentify the structural features underlying this functionaldiversity. The final rK9 model is structurally similar to rK2,but variable regions surrounding the active site differ quitemarkedly from the reference proteins. The kallikrein loop, whichdiffers from that in porcine kallikrein by a seven-residue insertion,has been generated de novo and subjected to simulated annealingto assess its influence on the restricted substrate specificityof these proteinases. The proposed conformation of the specificitypocket in rK9 differs from that of other serine proteinases,but it can still accommodate both aromatic and basic amino acidside chains at the substrate P₁ position, thus explaining thedual chymotrypsin and trypsin-like activity of rK9. The electrostaticpotentials of rK9 and aprotinin were calculated using the finitedifference Poisson–Boltzmann method. They indicated alarge positive region near the active site of rK9 not foundin related proteinases because of positively charged residuesat positions 61 and 65 in rK9. They generate a positive region,which overlaps a positive region in aprotinin, and may preventaprotinin binding. A single mutation in aprotinin is suggestedthat might allow kallikrein rK9 inhibition by aprotinin. Thismodel contributes significantly to our understanding of thestructure-function relationships among proteinases of the tissuekallikrein family.     

Physical mapping of chromosomes VII and XV of Saccharomyces cerevisiae at 3.5 kb average resolution to allow their complete sequencing

The high resolution complete physical maps of chromosomes VII and XV were constructed to form the basis for sequencing these chromosomes as part of the European systematic sequencing programme of the yeast genome, using a unique cosmid library from strain FY1679, and an original top-down mapping strategy involving I-Sce I chromosome fragmentation. A total of 138 and 196 cosmid clones were used to construct the maps for VII and XV, respectively, forming two unique contigs that cover the entirety of chromosomes (1091 kb each), except the telomeric repeats. Colinearity of the cosmid inserts with yeast DNA was verified, and the physical maps were eventually compared with the independently generated genetic maps.     

Validation of BTRHEOM,the new rheometer for soft-to-fluid concrete

An investigation was performed on the objectivity of a new rheometer for soft-to-fluid concrete, called BTRHEOM. Firstly, the influence of concrete wall friction on the measurement of the Bingham constants was studied by finite-element simulations. It has been shown that this influence is limited, in particular on the measurement of shear yield stress. However, the quality of the estimate of plastic viscosity can be improved by applying a reduction of 10% to the bulk value. Secondly, a series of comparative tests was conducted with two other rheometers with different operating principles. The comparison with the intrinsic values as measured by a big coaxial-cylinder viscometer, the CEMAGREF-IMG rheometer, showed a satisfactory result for yield stress, but not for plastic viscosity, probably due to the segregation of the coarse aggregate in the CEMAGREF-IMG rheometer. For two concretes without segregation, the two rheometers yielded the same values. Another comparison with the LAFARGE rheometer (a modified version of Tattersall's two-point test) showed a good correlation between the measurements with the two instruments. Finally, the slump test was modelled by a simple numerical approach, from which a linear relation between slump and yield stress was derived. This relationship agrees with the experimental results.     

稳定度0.1℃的PWM温度控制器

本文给出TEC(热电冷却器)温度控制器设计,它能使激光功率二极管(或其他元件)温度稳定在0.1℃之内. 环境温度变化会对大多数电子系统的精度有影响.把关键元件(如高性能晶振、SAW滤波器、光放大器、激光二极管)的本机温度限制在窄范围内可提高电子系统的精度.