306 research outputs found

    Internal quality of commercial eggs stored under conditions that simulate storage from laying to consumption

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    This study evaluated the effects on the internal quality of eggs of various storage environments through which eggs may pass between being laid and being consumed. Commercial eggs (N = 648) from Dekalb White hens were used. Treatments consisted of T1: 28 days at 4 °C; T2: 28 days at 20 °C; T3: 7 days at room temperature (27 °C ± 2 °C) (humidity 55%) and 21 days at 4 °C; T4: 7 days at room temperature and 21 days at 20 °C; T5: 14 days at room temperature and 14 days at 4 °C; T6: 14 days at room temperature and 14 days at 20 °C; T7: 21 days at room temperature and 7 days at 4 °C; T8: 21 days at room temperature and 7 days at 20 °C; and T9: 28 days at room temperature. The characteristics that were evaluated consisted of Haugh unit (HU), yolk index (YI), colour (L*, a* and b*), albumen pH, yolk pH and lipid oxidation. Eggs stored 28 days were darker (L*), and had greater yolk pH and lipid oxidation than fresh eggs. Eggs stored under T1 and T3 conditions had greater HU and YI than eggs stored in the other environments. The albumin pH of eggs stored at room temperature (T9) was highest of the treatments. Yellowness was increased in eggs stored under T4, T6, T8, and T9 conditions. Eggs should be stored under refrigeration as this promotes maintenance of internal quality and mitigates negative effects of previous storage conditions

    Photoacoustic Characterization Of Photovoltaic Cells

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    The photoacoustic characterization of Si solar-cell samples having distinct internal resistances, both at low and high modulation frequencies, yielded results significantly different from each other. For large samples with very small internal resistances (∌0.1 Ω), the additional contribution of the current dissipation near short-circuit conditions yielded results similar to those obtained with photothermal radiometry or the pyroelectric detection. For small samples, the results for the conversion efficiency, both at low and high modulation frequencies, are similar to ones obtained from the conventional electrical measurements.61115176517

    Prediction of lamb body composition using in vivo bioimpedance analysis

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    The objective of this study was to evaluate the potential of in vivo bioimpedance analysis (BIA) as a method to estimate body composition in lambs. Thirty-one Texel x Ile de France crossbreed ram lambs were slaughtered at pre-determined intervals of average weights of 20, 26, 32, and 38 kg. Before the slaughter of the animals, their body weight (BW) and body length (BL) were measured. The values for resistance (Rs) and reactance (Xc) were collected using a single-frequency BIA equipment (Model RJL Quantum II Bioelectrical Body Composition Analyzer). The BIA main variables such as body bioelectrical volume (V), phase angle (PA), resistive density (RsD), and reactive density (XcD) were then calculated. The soft tissue mass of the right-half cold carcass was analyzed in order to determine its chemical composition. Multiple regression analyses were performed using the lamb body composition as dependent variables and the measurements related to bioimpedance as independent variables. The best regression models were evaluated by cross-validation. The predictive model of moisture mass, which was developed by using XcD and V, accounted for 84% of its variation. Resulting models of percentage moisture (R2 = 0.79), percentage lean mass (R2 = 0.79), percentage fat (R2 = 0.79), and fat mass (R2 = 0.87) were obtained using RsD and V. Furthermore, the values of RsD regarding V, and PA in the prediction models accounted for 91% and 89% of variation in protein mass and lean mass, respectively. Bioimpedance analysis proved to be an efficient method to estimate the body composition of lambs slaughtered at different body mass stages

    Germ granule dysfunction is a hallmark and mirror of Piwi mutant sterility

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    In several species, Piwi/piRNA genome silencing defects cause immediate sterility that correlates with transposon expression and transposon-induced genomic instability. In C. elegans, mutations in the Piwi-related gene (prg-1) and other piRNA deficient mutants cause a transgenerational decline in fertility over a period of several generations. Here we show that the sterility of late generation piRNA mutants correlates poorly with increases in DNA damage signaling. Instead, sterile individuals consistently exhibit altered perinuclear germ granules. We show that disruption of germ granules does not activate transposon expression but induces multiple phenotypes found in sterile prg-1 pathway mutants. Furthermore, loss of the germ granule component pgl-1 enhances prg-1 mutant infertility. Environmental restoration of germ granule function for sterile pgl-1 mutants restores their fertility. We propose that Piwi mutant sterility is a reproductive arrest phenotype that is characterized by perturbed germ granule structure and is phenocopied by germ granule dysfunction, independent of genomic instability

    SobrevivĂȘncia e ocorrĂȘncia de muda em Triatoma infestans Klug (Hemiptera, Reduviidae) apĂłs choque de temperatura

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    Survival and molting occurrence were studied in specimens of Triatoma infestans over 30 days after temperature shocks. Hyperthermal and hypotermal shocks could be found to affect both survival and molting incidence as a function of temperature and period of the developement phase and sex of the specimens. Considering the various test conditions, the shock at 0°C for 12 h was found to elicit the most deleterious effect, whereas shocks at 40°C and 0°C even for 1 h are interpreted as affecting the hormonal balance which controls molting. Cases of a rise in post-shock survival are suggested to have been favored by heat-shock protein action.A sobrevivĂȘncia e a ocorrĂȘncia de mudas em espĂ©cimes de Triatoma infestans foram estudados num perĂ­odo de 30 dias apĂłs choques de temperatura. Foi demonstrado que choques hipertĂ©rmico e hipotĂ©rmico interferem nesses processos, na dependĂȘncia da temperatura do choque, tempo de sua duração, fase de desenvolvimento e sexo dos espĂ©cimes. Dentre as situaçÔes experimentais utilizadas, o choque a 0°C por 12 h pareceu produzir a ação mais deletĂ©ria, porĂ©m choques a 40°C e 0°C mesmo por uma hora sĂŁo admitidos como afetando o desenvolvimento hormonal que controla a muda. Casos de aumento de sobrevivĂȘncia pĂłs-choque sĂŁo sugeridos como tendo sido favorecidos por ação de proteĂ­nas de choque tĂ©rmico

    Angle-resolved photoemission in doped charge-transfer Mott insulators

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    A theory of angle-resolved photoemission (ARPES) in doped cuprates and other charge-transfer Mott insulators is developed taking into account the realistic (LDA+U) band structure, (bi)polaron formation due to the strong electron-phonon interaction, and a random field potential. In most of these materials the first band to be doped is the oxygen band inside the Mott-Hubbard gap. We derive the coherent part of the ARPES spectra with the oxygen hole spectral function calculated in the non-crossing (ladder) approximation and with the exact spectral function of a one-dimensional hole in a random potential. Some unusual features of ARPES including the polarisation dependence and spectral shape in YBa2Cu3O7 and YBa2Cu4O8 are described without any Fermi-surface, large or small. The theory is compatible with the doping dependence of kinetic and thermodynamic properties of cuprates as well as with the d-wave symmetry of the superconducting order parameter.Comment: 8 pages (RevTeX), 10 figures, submitted to Phys. Rev.

    ÎČ-amino alcohols and their respective 2-phenyl-N-alkyl aziridines as potential DNA minor groove binders

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    It is known that aziridines and nitrogen mustards exert their biological activities, especially in chemotherapy, via DNA alkylation. The studied scaffold, 2-phenyl-1-aziridine, provides a distinct conformation compared to commonly used aziridines, and therefore, leads to a change in high-strained ring reactivity towards biological nucleophiles, such as DNA. The above series of compounds was tested in three breast cell lines: MCF-10, a healthy cell; MCF-7, a hormone responsive cancer cell; and MDA-MB-231, a triple negative breast cancer cell. Both aziridines and their precursors, ÎČ-amino alcohols, showed activity towards these cells, and some of the compounds showed higher selectivity index than cisplatin, the drug used as control. When the type of cell death was investigated, the synthesized compounds demonstrated higher apoptosis and lower necrosis rates than cisplatin, and when the mechanism of action was studied, the compounds were shown to interact with DNA via its minor groove instead of alkylation or intercalation

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio
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