Partial characterization of the cohemolytic factor produced by Streptococcus uberis and comparison with the CAMP-factor

Exosubstances (cohemolysins) produced by Streptococcus agalactiae (CAMP-factor) and Streptococcus uberis (Uberis-factor) showing hemolytic synergism with beta-lysin produced by Staphylococcus aureus were compared. Cohemolytic activity was evaluated in the supernatants of bacterial cultures, before and after ammonium sulfate precipitation. Sheep erythrocytes sensitized with beta-lysin were used as substrate. The assays were performed in microtiter plates and results were expressed as cohemolytic units/ml. Maximum cohemolytic activity was detected, respectively, after 8 h and 14 h of growth in Columbia broth in S. uberis and S. agalactiae cultures. Cohemolytic activities of both microorganisms showed similarities when submitted to various physical and chemical treatments. They were significantly decreased by heating at 60 degrees C and 100 degrees C, or in presence of trypsin, and were abolished in the presence of Tween 20. Activities were found to be stable in crude supernatants and concentrated preparations maintained at -20 degrees C for 3 months. Differences were related to levels of activity and kinetics of detection during the growth cycle. The results indicate the proteic nature, at least in part, of the Uberis factor. Analysis by PAGE in the presence or absence of SDS allowed us to correlate Uberis activity with a protein band with apparent molecular mass of 42 kDa, while CAMP activity was associated with a protein band of 27 kDa.     

Adverse effects of pharmacological therapy for nicotine addiction in smokers following a smoking cessation program.

This multicenter, community-based, prospective, longitudinal study evaluated the safety of nicotine replacement therapy (NRT), bupropion, and combined therapy of NRT and bupropion for smokers seeking to quit, when these therapies were used under real-world conditions following a smoking cessation program. Participants were smokers aged 18 years or older who attended five smoking cessation clinics. Evaluations were made at 15, 30, 60, and 90 days. We investigated the possible existence of adverse effects as well as the severity of each adverse effect and its influence on the treatment course. The study included 904 smokers: 370 received NRT, 413 received bupropion, and 121 received combined therapy. At 15, 30, 60, and 90 days, adverse effects were reported by 43.8%, 33.1%, 22.3%, and 5.7% of subjects, respectively. Adverse effects were significantly more frequent in subjects receiving combined therapy or bupropion alone than in NRT-treated subjects at the 15-, 30-, and 60-day follow-ups. A total of 83 smokers (9.3%) withdrew from treatment and 116 (12.8%) stopped temporarily because of adverse effects. No differences were found in the percentages of discontinuation among the different treatment options. Adverse effects rarely were severe (n=10). Nevertheless, 41 subjects (4.5%) discontinued drug therapy indefinitely and 55 (6.1%) discontinued it temporarily because of mild adverse effects. Pharmacological therapies for smoking cessation are safe as long as they are appropriately prescribed and supervised by clinicians according to clinical practice guidelines. Adverse effects are primarily mild. Nonetheless, mild adverse effects may be perceived by patients as a serious enough problem to cause them to discontinue treatment.     

Proton conductivity in perovskite type yttrium doped barium hafnate

Yttria doped Ba-hafnates were prepared by solid state route and the proton conductivity of pressed samples of yttria doped barium hafnate was determined with impedance spectroscopy. The results are compared with existing data for cerates and zirconates. It was found that Ba-hafnates show a level of proton conduction that is comparable to that of doped Ba-zirconates at low and slightly higher at high temperatures. This is in agreement with the prediction based on the ionic radius of the tetravalent atom in the perovskite.     

Production of β‐galactosidase from recombinant Saccharomyces cerevisiae grown on lactose

Improved productivity and costs reduction in fermentation processes may be attained by using flocculating cell cultures. The production of extracellular heterologous β‐galactosidase by recombinant flocculating Saccharomyces cerevisiae cells, expressing the lacA gene (coding for β‐galactosidase) of Aspergillus niger under the ADHI promotor and terminator in a bioreactor was studied. The effects of lactose concentration and yeast extract concentration on β‐galactosidase production in a semi‐synthetic medium were analysed. The extracellular β‐galactosidase activity increased linearly with increasing initial lactose concentrations (5–150 g dm^?3). β‐Galactosidase production also increased with increased yeast extract concentration. During the entire fermentation, no accumulation of the hydrolysed sugars, glucose and galactose, was observed. The catabolic repression of the recombinant strain when cultured in a medium containing equal amounts of glucose and galactose was confirmed. In complete anaerobiosis, the fermentation of lactose resulted in a very slow fermentation pattern with lower levels of β‐galactosidase activity. The bioreactor operation together with optimisation of culture conditions (lactose and yeast extract concentration) led to a 21‐fold increase in the extracellular β‐galactosidase activity produced when compared with preliminary Erlenmeyer fermentations. Copyright © 2004 Society of Chemical Industry     

évaluation préliminaire des qualités psychométriques d'un système de codification du soutien conjugal pour le trouble de stress post-traumatique.

Lack of social support (SS) is one of the most important factors influencing the development and maintenance of post-traumatic stress disorder (PTSD), and people living in couples seek the support of their spouse. To our knowledge, no study on PTSD has used an observational measure of SS in addition of the usual self-report method of measurement. The purpose of this study is to adapt the Social Support Interaction Global Coding System (SCIS) and to explore its psychometric properties using 20 support interactions videotaped with couples among whom a spouse has a PTSD diagnosis. Results suggest that the new SCIS (PTSD) shows satisfactory interrater reliability, good internal consistency and good convergent validity with self-reported measures of perceived support and marital adjustment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dispersion characteristics of asymmetric coupled anisotropic dielectric waveguides using FDFD

The formulation is developed in the frequency domain and the finite difference method is used for the numerical solution of the scalar wave equation, written in terms of the transverse components of the magnetic field. As a result a conventional eigenvalue problem is obtained without the presence of spurious modes due to the implicit inclusion of the divergence of the magnetic field equal to zero. The formulation is developed to include biaxial anisotropic dielectrics with an index profile varying arbitrarily in the cross section of the waveguide under analysis. This formulation is then applied to the analysis of the influence on the dispersion characteristics of the dimensions of asymmetric coupled rectangular uniaxial anisotropic dielectric waveguides. As expected, the reduction of the height or the width of one of the rectangular dielectric waveguides causes the dispersion curves to move towards higher frequencies.     

Hydrodynamic considerations on optimal design of a three‐phase airlift bioreactor with high solids loading

The hydrodynamic study of a three‐phase airlift (TPAL) bioreactor with an enlarged gas–liquid dual separator was carried out. Different lengths and diameters of the draft tube were tested to show how the design of the separator zone affects the hydrodynamic performance of the TPAL reactor. Ca‐alginate beads with entrapped yeast biomass at different loadings (0, 7, 14 and 21% v/v) were used in order to mimic the solid phase of conventional high cell density systems, such as those with cells immobilized on carriers or flocculating cells. Important information on multiphase flow and distribution of gas and solid phases in the internal‐loop airlift reactor (ALR) with high solids loading was obtained, which can be used for suggesting optimal hydrodynamic conditions in a TPAL bioreactor with high solids loading. It is finally suggested that the ALR with a dual separator and a downcomer to riser cross‐sectional area ratio (A_D/A_R) ranging from 1.2 to 2.0 can be successfully applied to batch/continuous high cell density systems, where the uniform distribution of solid phase, its efficient separation of particles from the liquid phase, and an improved residence time of air bubbles inside the reactor are desirable. Copyright © 2003 Society of Chemical Industry     

Characterization of the Main Semiconductor Laser Static and Dynamic Working Parameters From CW Optical Spectrum Measurements

We present a complete characterization of the work parameters of several types of semiconductor lasers. Static parameters as: power, linewidth and linewidth enhancement factor and also dynamic parameters such as: relaxation oscillations, relative intensity noise and damping rates are calculated using measurements of the optical spectrum of the lasers operated in continuous-wave mode. Methods for the calculation of these parameters are described and applied to the lasers under test by means of a single general setup and a single set of measurements