An extended hydrodynamics model for inertial confinement fusion hohlraums

The European Physical Journal D - We studied the directional dependency of electronic stopping power of swift light ions in nickel using real-time time-dependent density functional theory. We...     

Cloning and Characterization of the Gene Encoding Alpha-Pinene Oxide Lyase Enzyme (Prα-POL) from <Emphasis Type="Italic">Pseudomonas rhodesiae</Emphasis> CIP 107491 and Production of the Recombinant Protein in <Emphasis Type="Italic">Escherichia coli</Emphasis>

The alpha-pinene oxide lyase (Prα-POL) from Pseudomonas rhodesiae CIP107491 belongs to catabolic alpha-pinene degradation pathway. In this study, the gene encoding Prα-POL has been identified using mapping approach combined to inverse PCR (iPCR) strategy. The Prα-POL gene included a 609-bp open reading frame encoding 202 amino acids and giving rise to a 23.7 kDa protein, with a theoretical isoelectric point (pI) of 5.23. The amino acids sequence analysis showed homologies with those of proteins with unknown function from GammaProteobacteria group. Identification of a conserved domain in amino acid in positions 18 to 190 permitted to classify Prα-POL among the nuclear transport factor 2 (NTF2) protein superfamily. Heterologous expression of Prα-POL, both under its native form and with a histidin tag, was successfully performed in Escherichia coli, and enzymatic kinetics were analyzed. Bioconversion assay using recombinant E. coli strain allowed to reach a rate of isonovalal production per gramme of biomass about 40-fold higher than the rate obtained with P. rhodesiae.     

Fed-batch Anaerobic Valorization of Slaughterhouse By-products with Mesophilic Microbial Consortia Without Methane Production

This work aimed at setting up a fully instrumented, laboratory-scale bioreactor enabling anaerobic valorization of solid substrates through hydrogen and/or volatile fatty acid (VFA) production using mixed microbial populations (consortia). The substrate used was made of meat-based wastes, especially from slaughterhouses, which are becoming available in large amounts as a consequence of the growing constraints for waste disposal from meat industry. A reconstituted microbial mesophilic consortium without Archaebacteria (methanogens), named PBr, was cultivated in a 5-L anaerobic bioreactor on slaughterhouse wastes. The experiments were carried out with sequential fed-batch operations, including liquid medium removal from the bioreactor and addition of fresh substrate. VFAs and nitrogen were the main metabolites observed, while hydrogen accumulation was very low and no methane production was evidenced. After 1,300 h of culture, yields obtained for VFAs reached 0.38 g/g dry matter. Strain composition of the microbial consortium was also characterized using molecular tools (temporal temperature gradient gel electrophoresis and gene sequencing).     

BTX Removal from Polluted Water Through Bioleaching Processes

In this study, benzene, toluene, and xylenes (BTX) removal from contaminated water by physical, chemical, and biological processes was studied. Results showed that air sparging in polluted water can reduce monoaromatic compounds from 140,000 to about 5 microg/l in only 1 h process with a gassing rate of 0.33 VVM. This method cannot be considered as a green technology as pollutants are only transferred from the liquid phase to the gas phase The ultimate objective of this research was thus to evaluate the efficiency of a strategy involving BTX adsorption by granular-activated charcoal (GAC) and subsequent regeneration of this support by a bioleaching process. Analysis of such processes requires the building of analytical tools able to accurately determine the contents of the contaminants in samples containing biomass to make possible the calculation of reliable material balances. Current investigation showed that BTX are readily trapped by GAC particles with low further release in the liquid medium whereas they remain at least partially available for in situ biodegradation. BTX adsorption onto the GAC was shown to reach maximum solute retention close to 350, 250, and 150 (as mg/g GAC) for xylenes, toluene, and benzene, respectively. This approach, which could afford efficient biological active carbon regeneration, is very promising for the removal of BTX compounds from water without any further environment damage.     

Dynamical description of transient x-ray lasers seeded with high-order harmonic radiation through Maxwell-Bloch numerical simulations

The Maxwell-Bloch code COLAX has been upgraded to use detailed hydrodynamical and collisional-radiative simulations of a soft x-ray laser plasma with traveling-wave pumping. The seeding of short pulses of high-order harmonics of the pump laser into the x-ray laser medium has been simulated. The amplification is shown to be a dynamic, two-stage process: the atomic dipoles of the lasing ions are first coherently excited by the short pulse, and subsequently generate a radiation wake which is amplified along its path through the plasma, with consequences on the experimentally recorded spectra.     

Fed-batch Production of Gluconic Acid by Terpene-treated Aspergillus niger Spores

Aspergillus niger spores were used as catalyst in the bioconversion of glucose to gluconic acid. Spores produced by solid-state fermentation were treated with 15 different terpenes including monoterpenes and monoterpenoids to permeabilize and inhibit spore germination. It was found that spore membrane permeability is significantly increased by treatment with terpenoids when compared to monoterpenes. Best results were obtained with citral and isonovalal. Studies were carried out to optimize spores concentration (10(7)-10(10) spores/mL), terpene concentrations in the bioconversion medium and time of exposure (1-18 h) needed for permeabilization of spores. Fed-batch production of gluconate was done in a bioreactor with the best conditions [10(9) spores/mL of freeze-thawed spores treated with citral (3% v/v) for 5 h] followed by sequential additions of glucose powder and pH-regulated with a solution containing 2 mol/L of either NaOH or KOH. Bioconversion performance of the spore enzyme was compared with the commercial glucose oxidase at 50, 60, and 70 degrees C. Results showed that the spore enzyme was comparatively stable at 60 degrees C. It was also found that the spores could be reutilized for more than 14 cycles with almost similar reaction rate. Similar biocatalytic activity was rendered by spores even after its storage of 1 year at -20 degrees C. This study provided an experimental evidence of the significant catalytic role played by A. niger spore in bioconversion of glucose to gluconic acid with high yield and stability, giving protection to glucose oxidase.