Magnetic hysteresis loop shift in NiFe(2)O(4) nanocrystalline powder with large grain boundary fraction

Magnetic properties of nanocrystalline NiFe(2)O(4) spinel mechanically processed for 350 h have been studied using temperature dependent from both zero-field and in-field (57)Fe Mossbauer spectrometry and magnetization measurements. The hyperfine structure allows us to distinguish two main magnetic contributions: one attributed to the crystalline grain core, which has magnetic properties similar to the NiFe(2)O(4) spinel-like structure (n-NiFe(2)O(4)) and the other one due to the disordered grain boundary region, which presents topological and chemical disorder features(d-NiFe(2)O(4)). Mossbauer spectrometry determines a large fraction for the d-NiFe(2)O(4) region(62% of total area) and also suggests a speromagnet-like structure for it. Under applied magnetic field, the n-NiFe(2)O(4) spins are canted with angle dependent on the applied field magnitude. Mossbauer data also show that even under 120 kOe no magnetic saturation is observed for the two magnetic phases. In addition, the hysteresis loops, recorded for scan field of 50 kOe, are shifted in both field and magnetization axes, for temperatures below about 50 K. The hysteresis loop shifts may be due to two main contributions: the exchange bias field at the d-NiFe(2)O(4)/n-NiFe(2)O(4) interfaces and the minor loop effect caused by a high magnetic anisotropy of the d-NiFe(2)O(4) phase. It has also been shown that the spin configuration of the spin-glass like phase is modified by the consecutive field cycles, consequently the n-NiFe(2)O(4)/d-NiFe(2)O(4) magnetic interaction is also affected in this process. (C) 2010 Elsevier B.V. All rights reserved.

Minas-type fresh cheese developed from buffalo milk with addition of L. acidophilus

Effective incorporation of a probiotic into foods requires the culture to remain viable all along processing and storage, without adverse alterations to sensory characteristics. The objective of this work was developing Minas-type fresh cheese with probiotic properties from buffalo milk. Four batches of Minas-type fresh cheese were prepared using buffalo milk: batch T1 in which neither culture nor lactic acid added; batch T3 in which only lactic acid added; batches T2 and T4 , both added of Lactobacillus acidophilus LAC 4, but T4 was also acidified. Resulting cheeses were evaluated for probiotic culture stability, texture profile, sensory acceptance, and changes in pH. The T4 probiotic cheese presented hardness, gumminess, and chewiness significantly lower than the other treatments. However, values for springiness and cohesiveness did not differ between all cheeses, and no sensory differences (p > 0.05) were found between treatments for texture, taste, and overall acceptance. The addition of probiotic to the acidified cheese (T4) yielded best aroma. The populations of L. acidophilus were greater than 10(6) CFU g-1 after 28 days of storage all products. Minas-type fresh cheese from buffalo milk is a suitable food for the delivery of L. acidophilus, since the culture remained viable during the shelf life of the products and did not negative affect analysed parameters.

Evaluation of elephant grass silage with the addition of cassava scrapings

The objective of this experiment was to evaluate the effects of adding cassava scrapings on gas and effluent losses, dry matter recovery, pH, contents of N-NH3, organic acids and volatile fatty acids and the bromatological composition of elephant grass silages. It was used a randomized complete design, with four levels of cassava scrapings (0, 7, 15 or 30% natural matter) each one with four replications per level. The grass was cut at 50 days of regrowth and ensiled in 15-L silos, equipped with a Bunsen valve to allow gas outflow. The gas losses decreased quadratically with the addition of cassava scrapings, whereas effluent losses decreased linearly. Dry matter recovery increased quadratically with the addition of cassava scrapings. Dry matter (DM) concentration increased but crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and hemicellulose (HEM) decreased linearly with the addition of cassava scrapings. The pH value and lactic acid concentration increased quadratically with the addition of cassava scrapings. Contents of N-NH3 and butyric acid decreased quadratically with the addition of cassava scrapings, whereas acetic acid content decreased linearly. Addition of cassava scrapings reduced gas and effluent losses and improved the fermentation profile of elephant grass silages and the level of 7% already ensures this improvement.

Características agronômicas do Panicum maximum cv. "Mombaça" submetido a níveis crescentes de fósforo

O objetivo deste experimento foi avaliar o efeito da adição de doses crescentes de P2O5 sobre a altura do dossel, o número de perfilhos e a produção de matéria seca de folhas e de colmos do capim-Mombaça, em diferentes idades. Foi conduzido um experimento implantado em um Nitossolo Vermelho Eutrófico. O delineamento experimental usado foi o de blocos completos casualizados, com quatro repetições, cinco doses de P2O5 (30, 60, 90, 120 e 150kg ha-1) e uma testemunha. Para a primeira e segunda coletas, observou-se o efeito linear do fósforo sobre o perfilhamento. Para a terceira e quarta coletas, os dados ajustaram-se ao modelo quadrático. A participação das lâminas foliares na matéria seca da parte aérea diminuiu com as doses de P2O5. Por outro lado, a participação de colmos aumentou com as doses de P2O5. A produção de matéria seca (MS) da parte aérea para primeira, segunda e terceira coletas respondeu de forma linear à aplicação de P2O5 observando-se um aumento estimado de 7, 15 e 19kg ha-1 de MS por kg ha-1 de P2O5, respectivamente. Para a quarta coleta, os dados ajustaram-se ao modelo quadrático de regressão, sendo a máxima produção, 8,3Mg ha-1 de MS, obtida com a aplicação de 103kg ha-1 de P2O5.

Productive performance and milk protein fraction composition of dairy cows supplemented with sodium monensin

The objective of this work was to evaluate the levels of sodium monensin on lactating cows and their effects on productive performance and milk protein fraction composition. It was used 12 Holstein cows, distributed in four balanced 3 × 3 Latin squares, and fed three diets: one control without monensin, and two diets with monensin at the levels of 24 or 48 mg/kg DM added to the concentrate. Milk production was daily measured throughout the entire experimental period. The samples used for analysis of milk composition were collected on two alternated days from the two daily milking. Non-protein nitrogen, total nitrogen and non-casein nitrogen contents were directly evaluated in the milk, and casein, whey protein and true protein contents were indirectly determined. The use of monensin in the rations reduced dry matter and nutrient intake, especially when diet with 48 mg/kg of dry matter was given. The ration with 24 mg/kg of DM increased milk production, with or without correction, and also fat and lactose yield, and it improved productive efficiency. The levels of monensin in the ratios did not influence contents of milk crude protein, non-protein nitrogen, non-casein nitrogen, true protein, casein, casein/true protein ratio, whey protein, and of all those fractions expressed as percentage of crude protein. The utilization of monensin in the ratio at the dose of 24 mg/kg of DM influences positively the productive performance of lactating cows, and it does not influence the composition of milk protein fractions.

Productive performance and composition of milk protein fraction in dairy cows supplemented with fat sources

The objective of this study was to evaluate the use of fat sources in rations for lactating cows on the productive performance and composition of milk protein fraction. Twelve Holstein cows were used, grouped in three balanced 4 × 4 Latin squares, fed with the following rations: control; refined soybean oil; whole raw soybean; and calcium salts of unsaturated fatty acid (Megalac-E). Dry matter and nutrient intake, and daily milk production were evaluated. The samples used to analyze milk composition were collected in two alternate days and were obtained from two daily milking. Milk composition and total nitrogen, non-protein nitrogen and non-casein nitrogen ratios were analyzed. The casein, serum protein and true protein ratios were obtained by difference. Dry matter and nutrient intakes were lower when cows received the diet containing calcium salts of fatty acids, in relation to the control diet. Among the diets with fat sources, the one with whole raw soybean and calcium salts decreased milk production. There was no effect of fat sources added to the diet on crude protein, non-protein nitrogen, non-casein nitrogen, true protein, casein, casein/milk true protein ratio and serum protein. Similarly, the experimental diets did not influence the protein fractions when expressed in percentage of milk crude protein. The utilization of fat sources in diets changes milk production and composition of lactating cows, but does not influence the composition of milk protein fractions.

Fracionamento dos carboidratos pelas equações do Cornell Net Carbohydrate and Protein System de três cultivares de girassol na presença ou não de irrigação

Objetivou-se quantificar as frações de carboidratos pelas equações do Cornell Net Carbohydrate and Protein System (CNCPS) de três cultivares de girassol (Helianthus annuus L.) cultivados na presença ou não de irrigação. A utilização de uma preparação fibrosa, denominada parede celular (PC), nas equações da CNCPS, em substituição à fibra em detergente neutro (FDN) não promoveu diferenças nas frações de carboidratos B1 e C, mas influenciou as frações A e B2. Como os valores da fração B1, obtidos pelo modelo CNCPS foram menores que os teores de amido e pectina determinados em laboratório, supõe-se que a pectina e outros oligossacarídeos da parede celular, solubilizados pela solução de detergente neutro (fibra solúvel), nunca fizeram parte da fração B1, e sim da fração A. Apesar de os carboidratos da fibra solúvel apresentarem elevadas taxas de degradação, não parece adequada a caracterização da fibra solúvel na fração A. Parece mais adequado que a fibra solúvel (que inclui a pectina) seja alocada a uma fração exclusivamente sua, que pode ser a fração B2, e que seja criada uma nova fração, a B3, para os carboidratos digeríveis da parede celular. Assim, a fração B1 seria composta apenas de amido. A equação da fração C, que estima os carboidratos indigeríveis da parede celular, pode ser simplificada, relacionando a fração indigerível ao teor de lignina na matéria seca, e não à FDN isenta de cinzas e proteína, como atualmente utilizado. Esta proposta tem implicações práticas, uma vez que a fração indigerível da parede celular tem sido expressa em relação à FDN, e não na MS, com base no fato de que os efeitos inibitórios da lignina ocorrem sobre os componentes fibrosos da parede celular vegetal, e não sobre o conteúdo celular.

Lysine and zinc chelate in diets for brown laying hens: effects on egg production and composition

It was evaluated the effects of levels of digestible lysine and chelate zinc combined in the diet for laying on the egg quality. It was used 720 birds, from 48 to 60 weeks of age, distributed in a completely randomized design in a 3 × 5 factorial scheme with three levels of zinc and five levels of lysine, applied into six replicates in the experimental units of eight birds per plot. The levels were: 137, 309 and 655 ppm zinc and 0.482, 0.527, 0.582, 0.644 and 0.732% digestible lysine. It was not observed any interaction among digestible lysine and zinc for the primary variables of fractions and egg composition. Levels of zinc reduced egg weight, suggesting the lowest efficiency in nutrient intake. At the highest dietary concentration of zinc, the addition of digestible lysine coincided with a linear increase in shell weight. However, zinc addition, regardless of lysine level in the diet, resulted in the reduction of egg weight and of the percentage of mineral matter in the yolk, limiting the efficiency of mineral deposition in this fraction of the egg. Concentration of zinc that produced the best results was 137 ppm inasmuch as higher quantities limit the use of digestible lysine, with effects harming composition and egg quality. The study indicates the following requirement for digestible lysine: 0.639% from the 48th to the 52nd week, 0.679% from the 52nd to 56th week, and 0.635% from the 56th to the 60th week. Considering the total period from 48th to the 60th week, the level 0.638% of lysine or the daily intake of 707 mg of the amino acid met the requirement for egg quality of semi-heavy layers used in this study.

Bioassay guided purification of the antimicrobial fraction of a Brazilian propolis from Bahia state

Background: Brazilian propolis type 6 (Atlantic forest, Bahia) is distinct from the other types of propolis especially due to absence of flavonoids and presence of other non-polar, long chain compounds, but presenting good in vitro and in vivo antimicrobial activity. Several authors have suggested that fatty acids found in this propolis might be responsible for its antimicrobial activity; however, so far no evidence concerning this finding has been reported in the literature. The goals of this study were to evaluate the antibacterial activity of the main pure fatty acids in the ethanolic extract and fractions and elucidate the chemical nature of the bioactive compounds isolated from Brazilian propolis type 6. Methods: Brazilian propolis type 6 ethanolic extract (EEP), hexane fraction (H-Fr), major fatty acids, and isolated sub-fractions were analyzed using high performance liquid chromatography (HPLC), high resolution gas chromatography with flame ionization detection (HRGC-FID), and gas chromatography-mass spectrometry (GC-MS). Three sub-fractions of H-Fr were obtained through preparative HPLC. Antimicrobial activity of EEP, H-Fr, sub-fractions, and fatty acids were tested against Staphyloccus aureus ATCC 25923 and Streptococcus mutans Ingbritt 1600 using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Results: EEP and H-Fr inhibited the growth of the microorganisms tested; nevertheless, no antimicrobial activity was found for the major fatty acids. The three sub-fractions (1, 2, and 3) were isolated from H-Fr by preparative HPLC and only sub-fraction 1 showed antimicrobial activity. Conclusion: a) The major fatty acids tested were not responsible for the antimicrobial activity of propolis type 6; b) Sub-fraction 1, belonging to the benzophenone class, was responsible for the antimicrobial activity observed in the present study. The identification of the bioactive compound will improve the development of more efficient uses of this natural product.

Assessing influence in survival data with a cure fraction and covariates

Diagnostic methods have been an important tool in regression analysis to detect anomalies, such as departures from error assumptions and the presence of outliers and influential observations with the fitted models. Assuming censored data, we considered a classical analysis and Bayesian analysis assuming no informative priors for the parameters of the model with a cure fraction. A Bayesian approach was considered by using Markov Chain Monte Carlo Methods with Metropolis-Hasting algorithms steps to obtain the posterior summaries of interest. Some influence methods, such as the local influence, total local influence of an individual, local influence on predictions and generalized leverage were derived, analyzed and discussed in survival data with a cure fraction and covariates. The relevance of the approach was illustrated with a real data set, where it is shown that, by removing the most influential observations, the decision about which model best fits the data is changed.

Factor (NF) kappa B polymorphism is associated with heart function in patients with heart failure

Background: Cardiac remodeling is generally an adverse sign and is associated with heart failure (HF) progression. NFkB, an important transcription factor involved in many cell survival pathways, has been implicated in the remodeling process, but its role in the heart is still controversial. Recently, a promoter polymorphism associated with a lesser activation of the NFKB1 gene was also associated with Dilated Cardiomyopathy. The purpose of this study was to evaluate the association of this polymorphism with clinical and functional characteristics of heart failure patients of different etiologies. Methods: A total of 493 patients with HF and 916 individuals from a cohort of individuals from the general population were investigated. The NFKB1-94 insertion/deletion ATTG polymorphism was genotyped by High Resolution Melt discrimination. Allele and genotype frequencies were compared between groups. In addition, frequencies or mean values of different phenotypes associated with cardiovascular disease were compared between genotype groups. Finally, patients were prospectively followed-up for death incidence and genotypes for the polymorphism were compared regarding disease onset and mortality incidence in HF patients. Results: We did not find differences in genotype and allelic frequencies between cases and controls. Interestingly, we found an association between the ATTG(1)/ATTG(1) genotype with right ventricle diameter (P = 0.001), left ventricle diastolic diameter (P = 0.04), and ejection fraction (EF) (P = 0.016), being the genotype ATTG(1)/ATTG(1) more frequent in patients with EF lower than 50% (P = 0.01). Finally, we observed a significantly earlier disease onset in ATTG(1)/ATTG(1) carriers. Conclusion: There is no genotype or allelic association between the studied polymorphism and the occurrence of HF in the tested population. However, our data suggest that a diminished activation of NFKB1, previously associated with the ATTG(1)/ATTG(1) genotype, may act modulating on the onset of disease and, once the individual has HF, the genotype may modulate disease severity by increasing cardiac remodeling and function deterioration.

Influence of Caffeine and Chondroitin Sulfate on Swine Sperm Capacitation and In Vitro Embryo Production

Background: The establishment of an in vitro production (IVP) of embryo in swine allows the generation of embryos with the same quality as in vivo produced embryos with less costs and time. In order to achieve successful fertilization under normal circumstances in vivo, mammalian spermatozoa must first undergo capacitation and then acrosome reaction. The purpose of this study was compared the efficacious of IP/CFDA fluorescence and Coomassie Blue G (CB) staining to detect capacitated sperm cells in refrigerated and fresh semen. Morever, it was investigated the efficacious of caffeine and chondroitin sulphate to promote in vitro sperm capacitation and in vitro embryo produced (IVP) of swine embryos. Materials, Methods & Results: A sperm-rich fraction from ejaculate was obtained using the gloved-hand method and the gel-free fraction was separated using sterile gauze. The semen was diluted in BTS at a final concentration of 1.5 x 10(8) cells/mL. The sperm suspension was incubated for 2 h at 25 degrees C, refrigerated and maintained for 1 h at 15-18 degrees C (refrigerated group) or used immediately (fresh group). Sperm capacitation was assessed by IP/CFDA fluorescence and CB staining for both fresh and refrigerated semen. For PI/CFDA evaluation, a final solution containing 1.7 mM formaldehyde, 7.3 mM PI and 20 mM CFDA in 950 mu L saline was prepared. In the dark, 40 mu L PI/CFDA final solution was added to 10 mu L semen and after 8 min, slides were analyzed on epifluorescence microscopy. For CB evaluation, sperm cells were fixed in 4% paraformaldehyde for 10 min and centrifuged twice at 320 x g in ammonium acetate pH 9 for 8 min. A smear was made and stained with 2.75 mg/mL CB in solution containing 12.5% methanol, 25% glacial acetic acid and 62.5% water, for 2 min. The smear was washed in running water, air dried and sealed with Permount (R), diluted 2:1 in xilol to avoid staining oxidation. Our results showed that refrigeration did not affect sperm capacitation and comparing staining methods, the PI/CFDA combination was more efficient to detect capacitated sperm, when compared to CB staining. In experiment 2, we evaluated the effect of different incubation time (1 - 5 h) with chondroitin sulfate and caffeine on sperm capacitation. For in vitro fertilization, oocytes were obtained from slaughterhouse ovaries. Oocytes with a thick and intact cumulus oophurus layer and cytoplasm with homogenous granules were selected for in vitro maturation for 44 h. According to the results of experiment 2, it was used for in vitro fertilization refrigerated semen was capacitated with 50 mu g/mL chondroitin sulfate for 2 h or capacitated with 5 mu g/mL caffeine for 3 h. Six hours after insemination, cumulus oophorus cells were mechanically removed and oocytes were washed and incubated in microdrops of culture medium. Embryo development after fertilization with sperm capacitated with caffeine or chondroitin sulfate was evaluated on days 3, 5 and 7 of culture. No differences were observed in days 3 or 5 of in vitro culture. However, it was observed an increase on blastocyst rate on Day 7 of culture when caffeine was used as the capacitor agent. Discussion: Molecular basis of sperm capacitation is still poor understood. Sperm capacitation can occur in vitro spontaneously in defined media without addition of biological fluids. We observed that sperm capacitation increased as incubation period enlarged and it was observed using Coomassie blue G and PI/CFDA for fresh semen and for refrigerated semen. It can be concluded that the cooling of semen did not change their pattern of sperm capacitation and this is best assessed by IP/CFDA than by CB. In addition to the use of caffeine in sperm capacitation produces more blastocysts than the chondroitin sulfate after in vitro fertilization.

Influence of palm fatty acid distillate on rumen degradability and protozoa population in buffaloes

Oil and fat as energy sources at low cost are relevant in ruminant nutrition. The aim of this study was to evaluate the effects of palm fatty acid distillate (PFAD) on the degradability and ciliate protozoa population in buffalo. Four rumen fistulated buffaloes were fed a basal diet in a Latin square (4x4) design trial. Treatments were designed with four of different levels of PFAD added directly into the rumen: 0; 200; 420 and 500 g/animal/d. High levels of PFAD (420 and 500 g/d) promoted higher degradation of the soluble fraction and lower in potentially degradable fraction of dry matter (DM) and neutral detergent fibre (NDF) with lower values of potential and effective degradability in two evaluated grasses, bermudagrass and brachiariagrass. Significant decreases in the total number of protozoa/mL of rumen content, Entodinium and ciliates belonging to subfamily Diplodiniinae were observed at higher level of PFDA addition in the rumen. Also, Epidinium and Holotrich ciliates disappeared from the rumen. Significant correlations were observed of the ciliate concentration and composition as a function of dietary lipids content. Entodinium composition increased from 68.0% to 99.6% and Diplodiniinae reduced from 30.4% to 0.4% with increasing PFAD level indicating higher fat toxicity effect on the Diplodiniinae ciliates than Entodinium species and direct action of the larger ciliates on the fibre degradation.

Fossil groups in the Millennium Simulation Evolution of the brightest galaxies

Aims. We create a catalogue of simulated fossil groups and study their properties, in particular the merging histories of their first-ranked galaxies. We compare the simulated fossil group properties with those of both simulated non-fossil and observed fossil groups. Methods. Using simulations and a mock galaxy catalogue, we searched for massive (>5 x 10(13) h(-1) M-circle dot) fossil groups in the Millennium Simulation Galaxy Catalogue. In addition, we attempted to identify observed fossil groups in the Sloan Digital Sky Survey Data Release 6 using identical selection criteria. Results. Our predictions on the basis of the simulation data are: (a) fossil groups comprise about 5.5% of the total population of groups/clusters with masses larger than 5 x 10(13) h(-1) M-circle dot. This fraction is consistent with the fraction of fossil groups identified in the SDSS, after all observational biases have been taken into account; (b) about 88% of the dominant central objects in fossil groups are elliptical galaxies that have a median R-band absolute magnitude of similar to-23.5-5 log h, which is typical of the observed fossil groups known in the literature; (c) first-ranked galaxies of systems with M > 5 x 10(13) h(-1) M-circle dot, regardless of whether they are either fossil or non-fossil, are mainly formed by gas-poor mergers; (d) although fossil groups, in general, assembled most of their virial masses at higher redshifts in comparison with non-fossil groups, first-ranked galaxies in fossil groups merged later, i.e. at lower redshifts, compared with their non-fossil-group counterparts. Conclusions. We therefore expect to observe a number of luminous galaxies in the centres of fossil groups that show signs of a recent major merger.

The number of reproductive workers in highly eusocial Hymenoptera: monogyny and monandry

Haplodiploidy results in relatedness asymmetries between colony members of highly eusocial Hymenoptera. As a consequence, queen and reproductive workers are more related to their own sons than to each other's male offspring. Kin selection theory predicts multiple optima in male parentage: either the queen or the workers should produce all the males. Nevertheless, shared male parentage is common in highly eusocial hymenopterans. An inclusive fitness model was used to analyze the effect of the number of reproductive workers on male parentage shared by the queen and laying workers by isolating the male component from an inclusive fitness equation using the equal fitness through male condition for each pairwise combination of the three female classes comprised of the queen, laying workers and non-laying workers. The main result of the theoretical analyses showed that the fraction of males produced by workers increases asymptotically with the number of laying workers at an increasingly diminishing rate, tending to an asymptotic value of 0.67. In addition, as the number of laying workers increases, the share of male parentage converges to that of non-laying workers. The diminishing return effect on male parentage share depending on the number of reproductive workers leads us to expect the number of reproductive workers to be relatively small in a stingless bee colony, even in the absence of productivity costs. The available data confirms this hypothesis, as there is an unusually small number of reproductive workers in stingless bee colonies.