Use of chemically modified silica with beta-diketoamine groups for separation of alpha-lactoalbumin from bovine milk whey by affinity chromatography

Silica gel surface was chemically modified with beta-diketoamine groups by reacting the silanol from the silica surface with 3-aminopropyl-triethoxysilane and 3-bromopentanedione, With this material, copper ions were adsorbed from aqueous solutions, the chemical analysis of the silica-gel-immobilized acetylacetone provided a quantity of 0.67 mmol g(-1) of organic groups attached to the support and 0.63 mmol g(-1) of copper, This material was used as a stationary phase in IMAC (immobilized metal affinity chromatography), to separate alpha-lactoalbumin from bovine milk whey, the results showed an efficient separation in the chromatographic column, the possibility of reutilization of the stationary phase was also investigated. (C) 1997 Academic Press

New X-ray powder diffraction data and Rietveld refinement for Gd2O3 monodispersed fine spherical particles

Nominally pure Gd2O3 C-form structure from basic carbonate fine spherical particles and its differences concerning the XRD data among literature patterns using Rietveld method is reported. Gd2O3: Eu3+ from basic carbonate and Gd2O3 from oxalate were also investigated. All samples, except the one from oxalate precursor, are narrow sized, 100-200 nm. Only non-doped Gd2O3 from basic carbonate presents XRD data with smaller d(hkl) values than the literature ones. From Rietveld refinement, non-doped Gd2O3 from basic carbonate has the smallest crystallite size and from oxalate shows the greatest one. Also, the unit cell parameters indicate a plan contraction of the Gd2O3 from basic carbonate. The presence of Eu3+ increases crystallite size when basic carbonate precursor is used to prepare Gd2O3 and avoids plan contraction. The structural differences observed among Gd2O3 samples obtained are related to the type of precursor and to the presence or not of doping ion. (C) 2003 Elsevier B.V. (USA). All rights reserved.

Preparation and characterization of nanosized SrBi2Nb2O9 powder by the combustion synthesis

This work presents the preparation of SrBi2Nb2O9 (SBN) directly by the combustion synthesis. Strontium nitrate, niobium ammonium oxalate (NH4H2[NbO-(C2O4)(3)].3H(2)O) and bismuth oxide were used as oxidant reactants and urea as fuel. The influence of the fuel was evaluated by the addition of different fuel amounts (50%, 100%, 200% and 300%), 100% being the stoichiometric proportion. The XRD patterns showed that the SBN perovskite crystallized as the majority phase. The as-synthesized stoichiometric powder presented a specific surface area of around 13 m(2)/g and a mean grain size of around 16 nm. Dilatometric measurements showed that the maximum sintering rate occurs at 1275degreesC. The determination of the ferroparaelectric transition showed a Curie temperature (T-c) of 429degreesC. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Effect of additives and powder preparation techniques on PTCR properties of barium titanate

PTCR barium titanate has been prepared following two different powder preparation techniques: the solid-state reaction route and co-precipitation route for the comparison of results. The co-precipitation route produces better PTCR characteristics with low room temperature resistivity and better reproducibility of prepared samples. The effects of different concentrations of additives like donors, acceptors and excess titanium have been optimized to get good quality PTCR samples. (C) 2002 Elsevier B.V. B.V. All rights reserved.

Genetic parameters estimates for milk, fat and protein yield analyzed by test day models for Murrah buffaloes in Brazil

The objectives of this study were to estimate genetic parameters for test-day milk, fat and protein yields, in Murrah buffaloes. In this study 4,757 complete lactations of Murrah buffaloes were analyzed. The (co) variance components were estimated by restricted maximum likelihood using MTDFREML software. The bi-trait animal test-day models included genetic additive direct and permanent environment effects, as random effects, and the fixed effects of contemporary group (herds-year-month of control) and age of the cow at calving as linear and quadratic covariable. The heritability estimate at first control was 0.19, increased until the third control (0.24), decreasing thereafter, reaching the lowest value at the ninth control (0.09). The highest heritability estimates for fat and protein yield were 0.23 (first control) and 0.33 (third control), respectively. For milk yield, genetic and phenotypic correlation estimates ranged from 0.37 to 0.99 and from 0.52 to 0.94, respectively. Genetic correlations were higher than phenotypic ones. For fat and protein yields, genetic correlation estimates ranged from 0.42 to 0.97.

Internal standardization in graphite furnace atomic absorption spectrometry: Comparative use of As and Ge to minimize matrix effects on Se determination in milk

Arsenic and germanium have been evaluated as internal standards to minimize matrix effects on the direct determination of selenium in milk by graphite furnace atomic absorption spectrometry (GFAAS) using tubes with integrated platform, pre-treated with W together with I'd as chemical modifier. The efficiency of As and Ge as internal standards for 25 mu g L-1 Se plus 500 mu g (L)-1 As or Ge in diluted (1 + 9 v/v) milk plus 1.0% (v/v) HNO3 was evaluated by means of correlation graphs plotted from the normalized absorbance signals (n = 20) of internal standard (axis gamma) versus analyte (axis x). The equations that describe the linear regression were: A(As)= - 0.004 +/- 0.019 +/- 1.02 + 0.019 A(Se) (r=0.9967 +/- 0.005); A(Ge)= - 0.0 17 +/- 0.015 + 1.01 +/- 0.015 A(Se) (r = 0.9978 +/- 0.004). Samples and reference solutions were automatically spiked with 500 mu g L-1 Ge or As and 1.0% (v/v) HNO3 by the autosampler. For 20 mu L of aqueous standard solutions, analytical curves in the 5.00-40.0 mu g L-1 Se range were established using the ratio of Se absorbance to internal standard absorbance (A(Se)A(IS)) versus analyte concentration, and good linear correlations were obtained. The characteristic mass was 40 pg Se. Limits of detection were 0.55 and 0.40 mu g L-1 with As and Ge as the internal standard, respectively. Relative standard deviations (RSD) for a sample containing 25 mu g L-1 Se were 1.2% and 1.0% (n = 12) using As and Ge, respectively. The RSD without internal standardization was about 6%. The accuracy of the proposed method was evaluated by an addition-recovery experiment and all recovered values were in the 99-105% range with IS and in the 70-80% range without IS. Using Ge as the internal standard, results of analysis of standard reference materials were in agreement with certified values at a 95% confidence level. The selenium concentration for 10 analyzed milk samples varied from 5.0 to 20 mu g L-1. (c) 2005 Elsevier B.V. All rights reserved.

Collapse and Color Changes in Grapefruit Juice Powder as Affected by Water Activity, Glass Transition, and Addition of Carbohydrate Polymers

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of drying method on the sorption isotherms and isosteric heat of persimmon pulp powder

Moisture equilibrium data of persimmon pulp powders with 50% maltodextrin (dry basis) obtained with different drying methods were determined at 20, 30, 40 and 50 degrees C. The spray-dryer gave a dry product with a higher adsorption capacity than the other methods. The vacuum- and freeze-dried products had the same adsorption capacity. The highest isosteric heat of sorption was observed for powders produced by spray-drying. The isokinetic temperature (T(B)) calculated for persimmon pulp powder obtained by vacuum-, spray- and freeze-drying were 541.4 K, 616.3 K, 513.2 K, respectively. The sorption process was spontaneous and enthalpy controlled.

Modification of surface properties of Ti-16Si-4B powder alloy by plasma immersion ion implantation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Analysis of Escherichia coli isolated from bovine mastitic milk

Rangel P. & Marin J.M. 2009. Analysis of Escherichia coli isolated from bovine mastitic milk. Pesquisa Veterinaria Brasileira 29(5): 363-368. Departamento de Morfologia, Estomatologia e Fisiologia, Faculdade de Odontologia de Ribeirao Preto, Universidade de São Paulo, Avenida do Cafe s/n, Campus USP, Ribeirao Preto, SP 14040-904, Brazil. E-mail: jmmarin@forp.usp.brMastitis has been recognized for some time as the most costly disease in dairy herds. From February to November 2004, 670 samples of bovine mastitic milk from which 231 Escherichia coli strains were isolated, were collected from two Brazilian states. The strains were screened for the presence of Shiga toxin-producing (stx 1 and stx 2) and intimin (eae) genes. Twenty (8.6%) strains were detected by PCR to harbor the Shiga toxin genes (8 the stx 1 gene, 12 the stx 2 gene and none both of them). Two (0.8%) of the Escherichia coli strains studied were eae positive non Shiga toxin-producing. The strains were also examined for resistance to 12 antimicrobial agents. The predominantly observed resistance was to tetracycline (92.2%), streptomycin (90.4%), nalidixic acid (88.3%), amikacin (86.5%) and cephalothin (84.8%). Multidrug resistance was found among 152 isolates (65.8%).

The relationship between dairy cow hygiene and somatic cell count in milk

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Application of compression test in analysis of mechanical and color changes in grapefruit juice powder as related to glass transition and water activity

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Quantitative Phase Analyses Through The Rietveld Method with X-Ray Powder Diffraction Data of Heat-Treated Carbamazepine Form III

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)