Adaptational changes in cellular fatty acid branching and unsaturation of Aeromonas species as a response to growth temperature and salinity

The effects of growth temperature and salinity on the cellular fatty acids were investigated on Aeromonas caviae, Aeromonas hydrophila and Aeromonas sobria. Under optimal growth conditions, fatty acids patterns were dominated by even-numbered chains C(16:0), C(16:1cis9), C(18:1cis11), C(12:0) and C(14:0). Growth temperature modifications induced, in the three Aeromonas species, important changes in fatty acid (i) unsaturation, (ii) branching and (iii) chain length. An important decrease in the C(18:1cis11) fatty acid content was observed for the three species below 15 degrees C and above 25 degrees C. The evolution of C(18:1cis11) and C(16:0) showed a mirror image for the three Aeromonas species. Low NaCl concentrations did not elicit significant changes in the fatty acids content of the three Aeromonas species. However, for high NaCl concentration in the medium, the growth ability was related to an important decrease of the unsaturated to saturated fatty acids ratio indicating a membrane rigidification. Thermal and salinity adaptations were branched fatty acid-dependent for A. caviae, whereas this phenomenon was less significant for A. hydrophila and A. sobria.     

An experimental and numerical study of the suppression of jets,counterflow, and backflow in vortex units

Vortex units are commonly considered for various single and multiphase applications due to their process intensification capabilities. The transition from gas-only flow to gas–solid flow remains largely unexplored nonetheless. During this transition, primary flow phenomenon, jets, and secondary flow phenomena, counterflow and backflow, are substantially reduced, before a rotating solids bed is established. This transitional flow regime is referred to as the vortex suppression regime. In the present work, this flow transition is identified and validated through experimental and computational studies in two vortex units with a scale differing by a factor of 2, using spherical aluminum and alumina particles. This experimental data supports the proposed theoretical particle monolayer solids loading that allows estimation of vortex suppression regime solids capacity for any vortex unit. It is shown that the vortex suppression regime is established at a solids loading theoretically corresponding to a monolayer being formed in the unit for 1g-Geldart D- and 1g-Geldart B-type particles. The model closely agrees with experimental vortex suppression range for both aluminum and alumina particles. The model, as well as the experimental data, shows that the flow suppression regime depends on unit dimensions, particle diameter, and particle density but is independent of gas flow rate. This combined study, based on experimental and computational data and on a theoretical model, reveals the vortex suppression to be one of the basic operational parameters to study flow in a vortex unit and that a simple monolayer model allows to estimate the needed solids loading for any vortex device to induce this flow transition.     

Initial Sintering of Submicrometer Titania Anatase Powder

Measurements of surface area reduction of TiO₂ anatase powder (of initially 100 m²· g⁻¹) were carried out for various partial pressures of water and oxygen at 823 K. The kinetic equation obtained for the experimental rates has the formulation r = k[P _H2O]^1/α [ P _O2]^1/β where α and β are equal to 2 and -12, respectively. A mechanistic model involving six consecutive elementary steps was developed, in which hydroxyl species play a dominant role. No geometrical assumption is required. The general expression of the deduced theoretical rates has the same form as previously given. The comparison between the experimental and the predicted rates points out that the rate-limiting step is the surface diffusion of hydroxyl species. This model can easily be used for any other compounds, for particle growth, and for porosity elimination.     

Organizing drug injectors against AIDS: Preliminary data on behavioral outcomes.

Describes a project based on organizing drug injectors to change their subculture in ways that promote lower risk behaviors. Initial and follow-up interviews were conducted with 368 Ss. Findings indicate a decline in high-risk behaviors such as renting or borrowing used syringes and an increase in risk-reducing behaviors such as using new syringes and condoms. Almost half the Ss entered drug abuse treatment during the follow-up period; 60% taught others to use bleach to decontaminate injecting equipment. Risk reduction was greater among Ss who attended group meetings. Thus, organizing drug injectors is a feasible intervention that should be adopted elsewhere. Drug injectors can take on responsibility in combating AIDS. All evaluations of interventions should measure Ss' efforts to spread the message to others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Photodynamic effect on the specific antitumor immune activity

Patients with mesial temporal lobe epilepsy (MTLE) have asymmetric hippocampal volumes with atrophy that sometimes by visual inspection appears to favor different regions along the longitudinal axis of the affected hippocampus. Histological studies suggest that cell loss may affect the anterior hippocampus preferentially, and that hippocampal sclerosis (HS) limited to the anterior of the hippocampus may indicate better surgical outcome. We used volumetric magnetic resonance imaging (MRI): (1) to objectively describe the distribution of volume loss in HS; and (2) to relate this distribution to outcome of temporal lobectomy. Hippocampal volumes and anterior and posterior subvolumes (AHV, PHV) were measured from MP-RAGE MRI in 43 temporal lobectomy patients with MTLE determined by pathological findings of HS and compared to 23 age-matched controls. Atrophy was defined as 'anterior', 'diffuse', 'posterior', or 'normal' depending on position of AHV and PHV relative to the mean +/- 2 S.D. of regional volumes of control hippocampi. Anterior to posterior ratios (APR = AHV/PHV) were also calculated. Mean APR of hippocampi ipsilateral to lobectomy cannot be distinguished from hippocampi contralateral to lobectomy or from controls. AHV and PHV from hippocampi contralateral to temporal lobectomy were smaller than controls but larger than hippocampi ipsilateral to lobectomy. Surgical outcome was independent of longitudinal distribution of atrophy. We determined that overall volume loss in HS is diffuse, neither clearly favoring the head nor body-tail. Surgical outcome for MTLE is not related to the longitudinal distribution of atrophy revealed by volumetric MRI.     

Performances des amplificateurs distribués en régime grand signal

This paper deals with the application of distributed amplifier as a power amplifier. Theoretical results obtained by using thespice II program will be presented and compared with measurements up to 12 GHz. It will be shown that small signal properties can be applied for large signal conditions. Large signal measurements give a constant gain of 6 dB in a frequency range from 1 to 10 GHz with an output power of 19 dBm.     

Reinforcement effects in fractal-structure-filled rubber

A quantitative morphological analysis has been performed using AFM and SAXS measurements in order to determine the spatial distribution of fillers in silica SBR composites. The proportion of fillers in agglomerates or aggregates of silica has thus been separated. Additional measurements have been carried out to quantify the amount of modified polymer in the vicinity of the filler surface, i.e. the bound rubber. It is shown that the reinforcing phase, constituting both silica particles and bound rubber, can be considered either as the dispersed or the continuous phase depending on the filler content.The linear dynamic mechanical properties of composites are then analysed. The variations of the shear modulus as a function of the filler content are then related to either the reinforcement effect induced by fillers or the development of specific additional interactions between phases, i.e. the interface effects. To separate the respective contribution of these effects from the overall dynamic behaviour of composites, micromechanical modelling is then performed. In a first step, the viscoelasticity of composites reinforced by 5.7 vol% of silica is predicted with the help of Christensen and Lo's model. For composites filled with 10 and 15 vol% of silica, self-consistent modelling, applied in a reverse mode, confirmed that the reinforcing phase, i.e. silica particles and bound rubber, acts as the continuous phase, in agreement with the morphological analysis. From the predicted dynamic mechanical properties of the reinforcing phase, the bound rubber behaviour is thus extracted as a function of the filler content and compared to that of unfilled SBR.     

Thermodynamic evaluation and optimization of Al-La, Al-Ce, Al-Pr, Al-Nd and Al-Sm systems using the Modified Quasichemical Model for liquids

The Al-La, Al-Ce, Al-Pr, Al-Nd and Al-Sm (Al-light rare earth) binary systems have been systematically assessed and optimized based on the available experimental data and ab-initio data using the FactSage thermodynamic software. Optimized model parameters of the Gibbs energies for all phases which reproduced all the reliable experimental data to satisfaction have been obtained. The optimization procedure was biased by putting a strong emphasis on the observed trends in the thermodynamic properties of Al-RE phases. The Modified Quasichemical Model, which takes short-range ordering into account, is used for the liquid phase and the Compound Energy Formalism is used for the solid solutions in the binary systems. It is shown that the Modified Quasichemical Model used for the liquid alloys permits us to obtain entropies of mixing that are more reliable than that based on the Bragg-Williams random mixing model which does not take short-range ordering into account.