Adsorption of mono- and multivalent cat- and anions on DNA molecules

Adsorption of monovalent and multivalent cat- and anions on a deoxyribose nucleic acid (DNA) molecule from a salt solution is investigated by computer simulation. The ions are modelled as charged hard spheres, the DNA molecule as a point charge pattern following the double-helical phosphate strands. The geometrical shape of the DNA molecules is modelled on different levels ranging from a simple cylindrical shape to structured models which include the major and minor grooves between the phosphate strands. The densities of the ions adsorbed on the phosphate strands, in the major and in the minor grooves are calculated. First, we find that the adsorption pattern on the DNA surface depends strongly on its geometrical shape: counterions adsorb preferentially along the phosphate strands for a cylindrical model shape, but in the minor groove for a geometrically structured model. Second, we find that an addition of monovalent salt ions results in an increase of the charge density in the minor groove while the total charge density of ions adsorbed in the major groove stays unchanged. The adsorbed ion densities are highly structured along the minor groove while they are almost smeared along the major groove. Furthermore, for a fixed amount of added salt, the major groove cationic charge is independent on the counterion valency. For increasing salt concentration the major groove is neutralized while the total charge adsorbed in the minor groove is constant. DNA overcharging is detected for multivalent salt. Simulations for a larger ion radii, which mimic the effect of the ion hydration, indicate an increased adsorbtion of cations in the major groove.Comment: 34 pages with 14 figure

HighP–TNano-Mechanics of Polycrystalline Nickel

We have conducted highP–Tsynchrotron X-ray and time-of-flight neutron diffraction experiments as well as indentation measurements to study equation of state, constitutive properties, and hardness of nanocrystalline and bulk nickel. Our lattice volume–pressure data present a clear evidence of elastic softening in nanocrystalline Ni as compared with the bulk nickel. We show that the enhanced overall compressibility of nanocrystalline Ni is a consequence of the higher compressibility of the surface shell of Ni nanocrystals, which supports the results of molecular dynamics simulation and a generalized model of a nanocrystal with expanded surface layer. The analytical methods we developed based on the peak-profile of diffraction data allow us to identify “micro/local” yield due to high stress concentration at the grain-to-grain contacts and “macro/bulk” yield due to deviatoric stress over the entire sample. The graphic approach of our strain/stress analyses can also reveal the corresponding yield strength, grain crushing/growth, work hardening/softening, and thermal relaxation under highP–Tconditions, as well as the intrinsic residual/surface strains in the polycrystalline bulks. From micro-indentation measurements, we found that a low-temperature annealing (T < 0.4 Tm) hardens nanocrystalline Ni, leading to an inverse Hall–Petch relationship. We explain this abnormal Hall–Petch effect in terms of impurity segregation to the grain boundaries of the nanocrystalline Ni

Search for neutrinoless decays tau -> lhh and tau -> lV0

We have searched for neutrinoless tau lepton decays into l h h or l V0, where l stands for an electron or muon, h for a charged light hadron, pi or K, and V0 for a neutral vector meson, rho, K*(892) and phi, using a 158 /fb data sample collected with the Belle detector at the KEKB e+e- collider. Since the number of events observed are consistent with the expected background, we set upper limits on the branching fractions in the range of 1.6-8.0 x 10-7 for various decay modes at the 90% confidence level.Comment: 15 pages, 4 figures, 2 tables, submitted to Phys. Lett.

Search for lepton flavor violating decays tau- -> l- pi0, l- eta, l- eta'

We have searched for lepton flavor violating semileptonic tau decays using a data sample of 153.8/fb accumulated with the Belle detector at the KEKB e+e- collider. For the six decay modes studied, the observed yield is compatible with the estimated background and the following upper limits are set at the 90% confidence level: B(tau- -> e- eta) mu- eta) < 1.5 x 10^-7, B(tau- -> e- pi0) mu- pi0) < 4.1 x 10^-7, B(tau- -> e- eta') mu- eta') < 4.7 x 10^-7. These results are 10 to 64 times more restrictive than previous limits.Comment: 14 pages, 13 figures, RevTex

Consumo de nutrientes e comportamento ingestivo de cordeiros da raça Santa Inês alimentados com rações com diferentes níveis de energia metabolizável

Objetivou-se avaliar o consumo de nutrientes e o comportamento ingestivo de cordeiros da raça Santa Inês na fase de cria alimentados com diferentes níveis de energia metabolizável (EM). Foram utilizados 20 cordeiros não-castrados, com idade e peso corporal médio de 50 dias e 13,00 ± 0,56 kg, respectivamente, distribuídos em quatro tratamentos experimentais com diferentes níveis de energia metabolizável (2,08; 2,28; 2,47 e 2,69 Mcal de EM/kg de matéria seca), em delineamento em blocos casualizados, com cinco repetições. Como volumoso utilizou-se feno de capim-tifton adicionado à ração concentrada. Os níveis de energia metabolizável (EM) tiveram efeito linear sobre os consumos de matéria seca, matéria orgânica, proteína bruta, extrato etéreo, carboidratos não-fibrosos e nutrientes digestíveis totais, expressos em g/dia. O consumo de FDN, expresso em %PV e kg/PV0,75, decresceu linearmente com o aumento dos níveis de energia nas rações, devido à redução no teor de FDN na matéria seca total das rações. Os tempos de alimentação e mastigação total, expressos em hora/dia, diminuíram linearmente com os níveis energéticos das rações experimentais. Em compensação, o tempo de ócio aumentou linearmente e o de ruminação não foi influenciado pelos níveis energéticos das rações. O número de bolos ruminais, de mastigações merícicas e de mastigações merícicas por bolo ruminal e o tempo de mastigações merícicas por bolo ruminal não foram influenciados pelos níveis de energia metabolizável nas rações. O aumento dos níveis de energia metabolizável das rações influencia o consumo de nutrientes e o comportamento ingestivo de cordeiros da raça Santa Inês na fase de cria.The objective of this work was to evaluate the nutrient intake and ingestive behavior of growing Santa Inês lambs fed different levels of metabolizable energy (ME). It was used 20 non-castrated lambs at 50 days of age and with 13.00 ± 0.56 kg of body weight. The animals were distributed into four experimental treatments with different levels of metabolizable energy (2.08, 2.28, 2.47 and 2.69 Mcal/kg of dry matter) in a randomized block design with five replications. It was used as roughage tifton hay added to concentrate diet. Levels of metabolizable energy (ME) linearly affected intakes of dry matter, organic matter, crude protein, ether extract, no-fiber carbohydrates, and total digestible nutrients, expressed in g/day. The NDF intake, expressed as % BW and kg/BW0.75, decreased linearly with the increase of levels of energy in the diet due to the reduction in NDF content in the total dietary dry matter. Feeding and total chewing time, expressed in hour/day, decreased linearly with the energy levels of the experimental diets. However, idle time increased linearly, whereas rumination was not influenced by energy levels of the diets. Number of ruminate boli, of ruminating chews, of ruminating chews per bolus and time of chewing per bolus were not influenced by levels of metabolizable energy in the diets. Increase in metabolizable energy levels of diets affects intake of nutrients and ingestive behavior of growing Santa Inês lambs

Comprehensive analysis of epigenetic clocks reveals associations between disproportionate biological ageing and hippocampal volume

The concept of age acceleration, the difference between biological age and chronological age, is of growing interest, particularly with respect to age-related disorders, such as Alzheimer’s Disease (AD). Whilst studies have reported associations with AD risk and related phenotypes, there remains a lack of consensus on these associations. Here we aimed to comprehensively investigate the relationship between five recognised measures of age acceleration, based on DNA methylation patterns (DNAm age), and cross-sectional and longitudinal cognition and AD-related neuroimaging phenotypes (volumetric MRI and Amyloid-β PET) in the Australian Imaging, Biomarkers and Lifestyle (AIBL) and the Alzheimer’s Disease Neuroimaging Initiative (ADNI). Significant associations were observed between age acceleration using the Hannum epigenetic clock and cross-sectional hippocampal volume in AIBL and replicated in ADNI. In AIBL, several other findings were observed cross-sectionally, including a significant association between hippocampal volume and the Hannum and Phenoage epigenetic clocks. Further, significant associations were also observed between hippocampal volume and the Zhang and Phenoage epigenetic clocks within Amyloid-β positive individuals. However, these were not validated within the ADNI cohort. No associations between age acceleration and other Alzheimer’s disease-related phenotypes, including measures of cognition or brain Amyloid-β burden, were observed, and there was no association with longitudinal change in any phenotype. This study presents a link between age acceleration, as determined using DNA methylation, and hippocampal volume that was statistically significant across two highly characterised cohorts. The results presented in this study contribute to a growing literature that supports the role of epigenetic modifications in ageing and AD-related phenotypes

Search for high-energy neutrinos from gravitational wave event GW151226 and candidate LVT151012 with ANTARES and IceCube

The Advanced LIGO observatories detected gravitational waves from two binary black hole mergers during their first observation run (O1). We present a high-energy neutrino follow-up search for the second gravitational wave event, GW151226, as well as for gravitational wave candidate LVT151012. We find two and four neutrino candidates detected by IceCube, and one and zero detected by Antares, within ±500 s around the respective gravitational wave signals, consistent with the expected background rate. None of these neutrino candidates are found to be directionally coincident with GW151226 or LVT151012. We use nondetection to constrain isotropic-equivalent high-energy neutrino emission from GW151226, adopting the GW event's 3D localization, to less than 2×1051-2×1054 erg. © 2017 American Physical Society