13,591 research outputs found
k-deformed Poincare algebras and quantum Clifford-Hopf algebras
The Minkowski spacetime quantum Clifford algebra structure associated with
the conformal group and the Clifford-Hopf alternative k-deformed quantum
Poincare algebra is investigated in the Atiyah-Bott-Shapiro mod 8 theorem
context. The resulting algebra is equivalent to the deformed anti-de Sitter
algebra U_q(so(3,2)), when the associated Clifford-Hopf algebra is taken into
account, together with the associated quantum Clifford algebra and a (not
braided) deformation of the periodicity Atiyah-Bott-Shapiro theorem.Comment: 10 pages, RevTeX, one Section and references added, improved content
Evitamento de minhocas Eisenia andrei (annelida, oligochaeta) a substratos tratados com calda bordalesa.
Production of grape juice powder obtained by freeze-drying after concentration by reverse osmosis.
This study aimed to evaluate the freeze-drying process for obtaining grape juice powder by reverse osmosis using 50% grape juice pre-concentrated (28.5 °Brix) and 50% hydrocolloids (37.5% maltodextrin and 12.5% arabic gum)
Electromagnetic Fields of Slowly Rotating Magnetized Gravastars
We study the dipolar magnetic field configuration and present solutions of
Maxwell equations in the internal background spacetime of a a slowly rotating
gravastar. The shell of gravastar where magnetic field penetrated is modeled as
sphere consisting of perfect highly magnetized fluid with infinite
conductivity. Dipolar magnetic field of the gravastar is produced by a circular
current loop symmetrically placed at radius at the equatorial plane.Comment: 5 pages, 2 figures, accepted for publication to Mod. Phys. Lett.
Influence of the concentration of locust bean gum on the gelling ability of whey peptic hydrolysates
The gelling ability of whey proteins can be changed by limited hydrolysis and by the
presence of other components such as polysaccharides; depending on the
environmental conditions it can either be improved or impaired.
In this work the effect of LBG on the heat-set gelation of aqueous whey protein
hydrolysates (10 % w/w) from pepsin was assessed at pH 7.0 by small deformation
rheology. Whey protein concentrate (WPC) and hydrolysates with a degree of
hydrolysis (DH) of 1.5, 2.5 and 4.9 % were used. Different LBG concentrations were
tested: 0, 0.1, 0.3 and 0.55 % (w/w).
The behaviour of gels from whey proteins or whey protein hydrolysates towards the
presence of LBG was very similar. The evolution of the viscous and storage moduli
followed the general behaviour reported for many biopolymer heat-set gelation
processes including whey proteins gelation. The increase in the LBG concentration
generally led to a decrease in the gel strength. However, for whey proteins a small
amount of LBG (0.1 %) leads to a big enhancement in the gel strength probably due to
an increase in the protein concentration of the protein enriched phase. Further
increases in the LBG concentration led to a decrease in the gel strength.
The gelation process is very sensible to environmental conditions and to processing
and often leads to rather coarse data. The factorial planning used allowed validating
conclusions using fewer experiments than those needed if no planning had been used,
while still getting statistical significance out of the results. However, as many factors
are involved, the modelling of the process was not straightforward
Spent-grains and zeolites as potential carriers for trypsin immobilisation
Trypsin is a widely used enzyme for protein hydrolysis and can be used to improve functional and
nutritional properties of foods.
The immobilization of enzymes on solid supports can offer several advantages over free enzymes including
easy handling, recovery from the reaction medium, reuse and operation in continuous reactors. Traditional
carriers include porous silica, porous glass and cellulose derivatives. Zeolites are porous alumino-silicates
available in a wide range of particle size and porosity and can also be used as carriers. Spent grains are a
brewing by-product with a high content in cellulose and can also be interesting as carriers for enzyme
immobilization because, besides having the necessary conditions (as stability, rigidity, low mass transfer
limitations, for instance), they are cheap and food grade.
This work proposes the use of spent grains and zeolites as alternative carriers for trypsin immobilization and
compares them with a traditional support (silica). Physical adsorption, ionic attachment and covalent
attachment to the supports were tested. The efficiency of immobilization and activity, as well as the
operation and storage stability of free and immobilized enzyme on the three supports were studied.
Trypsin was most successfully immobilized on the supports by covalent attachment using glutaraldehyde.
Though the best efficiencies were still obtained with silica, promising results were achieved with both spent
grains and zeolite.Fundação para a Ciência e a Tecnologia (FCT) - project POCTI/2000/QUI/36452.European Social Fund (ESF)
Desempenho fenotÃpico de hÃbridos transgênicos e convencionais no meio-norte brasileiro na safra 2010/2011.
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