NuTeV Structure Function Measurement

The NuTeV experiment obtained high statistics samples of neutrino and anti-neutrino charged current events during the 1996-1997 Fermilab fixed target run. The experiment combines sign-selected neutrino and anti-neutrino beams and the upgraded CCFR iron-scintillator neutrino detector. A precision continuous calibration beam was used to determine the muon and hadron energy scales to a precision of 0.7% and 0.43% respectively. The structure functions F_2(x,Q^2) and xF_3(x,Q^2) obtained by fitting the y-dependence of the sum and the difference of the neutrino and anti-neutrino differential cross sections are presented.Comment: Proceedings of the XIII international workshop on Deep Inelastic Scattering DIS 2005, 4 pages, 4 figure

Sonochemical synthesis and stabilization of concentrated antimicrobial silver-chitosan nanoparticle dispersions

This work reports on a green synthetic route to produce concentrated aqueous dispersions of silver nanoparticles (AgNP) employing high-intensity ultrasound (US) and chitosan (CS) as a non-toxic reducing agent for Ag1 salts and AgNP stabilizer. The sonication simultaneously boosted the synthesis and improved the stability of the AgNP, capping them with CS. Hybrid AgNP-CS antimicrobial dispersions, stable for at least 6 months, were synthesized in a simple single step process. The use of US allowed for applying relatively mild processing temperatures (608C) and reaction time between 30 min and 3 h to obtain concentrated disper- sions of AgNP that otherwise could not be obtained even after 72 h under mechanical stirring at the same reaction conditions. Upon sonication spherical AgNP-CS with a size between 60 and 100 nm were generated, in contrast to the average diameter of 200 nm of the particles obtained by stirring. The antibacterial efficiency of the AgNP-CS hybrids was evaluated against the medically relevant pathogens Staphylococcus aureus and Escherichia coli. The US-synthesized AgNP-CS showed more than 3-fold higher antibacterial activity compared to the particles obtained under stirring, due to their higher concentration and smaller size.Postprint (author's final draft

Nanotransformation of vancomycin overcomes the intrinsic resistance of Gram-negative bacteria

The increased emergence of antibiotic-resistant bacteria is a growing public health concern, and although new drugs are constantly being sought, the pace of development is slow compared with the evolution and spread of multidrug- resistant species. In this study, we developed a novel broad-spectrum antimicrobial agent by simply transforming vancomycin into nanoform using sonochemistry. Vancomycin is a glycopeptide antibiotic largely used for the treatment of infections caused by Gram-positive bacteria but inefficient against Gram-negative species. The nanospherization extended its effect toward Gram-negative Escherichia coli and Pseudomonas aeruginosa, making these bacteria up to 10 and 100 times more sensitive to the antibiotic, respectively. The spheres were able to disrupt the outer membranes of these bacteria, overcoming their intrinsic resistance toward glycopeptides. The penetration of nanospheres into a Langmuir monolayer of bacterial membrane phospholipids confirmed the interaction of the nanoantibiotic with the membrane of E. coli cells, affecting their physical integrity, as further visualized by scanning electron microscopy. Such mechanism of antibacterial action is unlikely to induce mutations in the evolutionary conserved bacterial membrane, therefore reducing the possibility of acquiring resistance. Our results indicated that the nanotransformation of vancomycin could overcome the inherent resistance of Gram-negative bacteria toward this antibiotic and disrupt mature biofilms at antibacterial-effective concentrations.Peer ReviewedPostprint (author's final draft

Immobilized laccase for decolourization of Reactive Black 5 dyeing effluents

enzyme (194 h free and 79 h immobilized) depended on the dyeing liquor composition and the chemical structure of the dye. In the decolourization experiments with immobilized laccase, two phenomenons were observed – decolourization due to adsorption on the support (79%) and dye degradation due to the enzyme action (4%). Dyeing in the enzymatically recycled effluent provided consistency of the colour with both bright and dark dyes

Bio-preparation of cotton fabrics

This study attempted to introduce the bio-processes in the conventional scouring and bleaching preparation of cotton. The scouring with two types of pectinases, acting under acidic and alkaline conditions respectively, was as efficient as the chemical process in terms of obtained adequate water absorbency of the fabrics. The necessity of surfactants application in scouring was outlined. Bleaching of the fabrics was performed with hydrogen peroxide, which was enzymatically produced by glucose oxidase during oxidation of glucose. The aeration plays an important role in the enhancement of the enzyme reaction, so that the quantity of generated peroxide is sufficient to overcome the stabilizing effect of the glucose and protein in the subsequent bleaching. A closed-loop process reusing starch containing desizing baths in a single step scouring/bleaching operation with enzyme-generated peroxide was performed. (C) 2001 Elsevier Science Inc. All rights reserved

Laccases to improve the whiteness in a conventional bleaching of cotton

This study reports for the first time on the enhancement of the bleaching effect achieved on cotton using laccase enzyme. Laccases applied in short-time batchwise or pad-dry processes prior to conventional peroxide bleaching, improved the end fabric whiteness. The whiteness level reached in the combined enzymatic/peroxide process was comparable to the whiteness in two consecutive peroxide bleaches. Effect of 10 min laccase pre-treatment at 60 8C, pH 5 on fabrics whiteness before and after a conventional hydrogen peroxide bleaching

Hydrogen peroxide generation with immobilized glucose oxidase for textile bleaching

Glucose oxidase was covalently immobilized on commercially available alumina and glass supports, with a high level of protein recovery. The operational stability of the alumina carrier was an advantage over the glass support, though the rate of generation of hydrogen peroxide in the case of the latter was higher. The immobilization technique provided repeated application of the enzyme even in low concentration, and the hydrogen peroxide generated in the enzymatic reaction was successively used for textile bleaching

Protein interactions in enzymatic processes in textiles

Enzymes are the catalysts of all reactions in living systems. These reactions are catalysed in the active sites of globular proteins. The proteins are composed by amino acids with a variety of side chains ranging from non-polar aliphatic and aromatic to acidic, basic and neutral polar. This fact allows to a globular 3D protein to create in the active site all ranges of microenvironments for catalysis. Major advances in microbial technology and genetics allow recently the broad range of enzymatic applications in the industry. Enzymatic processes have been increasingly incorporated in textiles over the last years. Cotton, wool, flax or starches are natural materials used in textiles that can be processed with enzymes. Enzymes have been used for desizing, scouring, polishing, washing, degumming, peroxide degradation in bleaching baths as well as for decolourisation of dyehouse wastewaters, bleaching of released dyestuff and inhibiting dye transfer. Furthermore many new applications are under development such as natural and synthetic fibres modification, enzymatic dyeing, finishing etc. Most of the textile processes are heterogeneous where an auxiliary as a dye, enzyme, softener or oxidant have to be taken from the solution to the fibre. These processes require the presence of surface-active agents, ionic force “balancers”, buffers, stabilisers and others, and are characterized with high turbulence and mechanical agitation in the textile baths. In this paper it is intended to understand and discuss the major protein interactions within textile processes and to try to anticipate troubleshooting possibilities when enzymes are used. It can be expected that an enzyme protein can interact with all chemical agents in solution due to the large variety of side chains of the outer-amino-acids in the large 3D structure of the protein. Without the aim of being exhaustive various points will be discussed where protein interactions are important for textile processing

Studies of stabilization of native catalase using additives

Native catalase preparations isolated from Bacillus Sp were formulated with different additives for storage stabilization and better performance at high temperature and pH. The additives studied were: polyethylene glycol, glycerol, BSA, casein, glutaraldehyde, n-butylamine, ethylenediamine, 1.6-diaminohexane, BSA/glutaraldehyde and casein/glutaraldehyde. The glycerol and glutaraldehyde showed the best performance for long-term storage at 30degreesC and neutral pH. No stabilization additives were effective at pH 12, but below that pH the polyethylene glycol and glycerol appeared to be the most appropriate. Amines, polyethylene glycol and glycerol shifted the pH activity maximum of the native catalase toward more alkaline region, while glycerol were the only additive to improve the temperature profile of the enzyme. (C) 2002 Elsevier Science Inc. All rights reserved