Search results for "Bioengineering"

Calculations on solvents and co-solvents of single-wall carbon nanotubes:cyclopyranoses

2005

The (10, 10) single-wall carbon nanotube (SWNT) presents consistency between relatively small solubility, and large partition coefficients and kinetic stability. The solubility of SWNTs is investigated in a variety of solvents, finding a class of non-hydrogen-bonding Lewis bases that provides good solubility. The organic solvent–water partition and hydrophobic moment of lysozyme show that the main contribution to the water-accessible surface area of helices is the hydrophobic term, while the hydrophilic part dominates in the sheet, which is related to the 1-octanol–, cyclohexane– and chloroform–water partition coefficients Po−ch−cf of helices, which are greater than those of the sheet. The …

Myrosinase activity and quality parameters on fresh-cut Chinese cabbage stored at two different temperatures

2009

Mixed microalgae culture for ammonium removal in the absence of phosphorus: Effect of phosphorus supplementation and process modeling

2014

Microalgal growth and ammonium removal in a P-free medium have been studied in two batch photobioreactors seeded with a mixed microalgal culture and operated for 46 days. A significant amount of ammonium (106 mg NH4-Nl(-1)) was removed in a P-free medium, showing that microalgal growth and phosphorus uptake are independent processes. The ammonium removal rate decreased during the experiment, partly due to a decrease in the cellular phosphorus content. After a single phosphate addition in the medium of one of the reactors, intracellular phosphorus content of the corresponding microalgal culture rapidly increased, and so did the ammonium removal rate. These results show how the amount of phos…

Exploring the potential of some yeast strains in the stereoselective synthesis of aldol reaction products and its reduced 1,3-dialcohol derivatives

2013

Abstract The behavior of two yeast strains has been studied under different conditions. Both microorganims catalyzed the aldol reaction between activated aldehydes and acetone when a large amount of the latter was present in the reaction medium producing, with moderate stereoselectivity, the aldol product with the R configuration. No reduction of any of the products present in the medium was detected. On the other hand, the carbonyl group of the racemic aldol was reduced to produce chiral 1,3-dialcohol derivatives when water was employed as the only solvent. In this case, the resolution of the racemic starting material was also possible with one of the biocatalysts, and the aldol was recove…

Influence of Micromixing on Microorganisms and Products

2001

The influence of mixing intensity as well as physical and chemical parameters on the cells of different microorganisms and the biosynthesis process is examined in this paper. Some reactions of cells effecting mixing intensity are described, such as retarded biomass growth, changes in aggregation and mutual arrangement of cells, morphological changes of cells and decreasing of biological activity, caused by an increased intensity of turbulence (turbohypobiosis). Several methods for investigating the local energy in reactors are compared. It is concluded that conventional methods of hydrodynamic analysis do not always allow valid results for the optimization of the mixing regime to be obtaine…

Biochemical aspects of stuck and sluggish fermentation in grape must

1998

Recently a number of studies have focused on the factors responsible for the occurrence of stuck and sluggish fermentations. Results from these studies indicate that together with nutritional deficiencies and inhibitory substances, technological practices could lead to such situations. This review explains, from a biochemical point of view, the influence of nutritional deficiencies, inhibitory substances and technological practices on yeast cell development and physiology and the fermentation process.

Nanoparticles and the immune system: challenges and opportunities

2016

Nanomedicine for immunotherapy

2016

Bimodal tracers synthesis for medical imaging PET/MRI

2015

Today physicians can use a wide variety of medical imaging techniques to establish early and accurate diagnosis. Nevertheless, each modality has its own advantages and drawbacks. This is why bi- or multimodality approach seems interesting. Among them, PET/MRI combination seems very promising because it can bring complementary informations. It is therefore necessary to inject to patients tracers specific to each imaging modality. This work described the synthesis of molecular platforms for MRI and PET imaging, according to 2 different strategies. The first one consisted in the synthesis of a DO3A macrocycle allowing the chelation of both gadolinium for MRI and gallium 68 for PET. The aim her…

Microalgae cultivation in wastewater: nutrient removal from anaerobic membrane bioreactor effluent

2012

This study investigated the removal of nitrogen and phosphorus from the effluent of a submerged anaerobic membrane bioreactor (SAnMBR) by means of a lab-scale photobioreactor in which algae biomass was cultured in a semi-continuous mode for a period of 42 days. Solids retention time was 2 days and a stable pH value in the system was maintained by adding CO2. Nitrogen and phosphorus concentrations in the SAnMBR effluent fluctuated according to the operating performance of the bioreactor and the properties of its actual wastewater load. Despite these variations, the anaerobic effluent proved to be a suitable growth medium for microalgae (mean biomass productivity was 234 mgl(-1) d(-1)), achie…