Susceptibility to Cronobacter sakazakii decreases with increasing age in neonatal CD-1 mice

Neonatal, premature, or very low birth weight infants fed reconstituted powdered infant formula contaminated with Cronobacter (Enterobacter sakazakii) may develop infections resulting in severe outcomes such as septicemia, necrotizing enterocolitis, meningitis, or death. Infants who recover from infection may have morbidities such as hydrocephalus, mental retardation, or developmental delays. Although increasing age appears to reduce susceptibility to Cronobacter infection, it is not known at what age or why these infants become less susceptible. Our study objectives were to compare the susceptibilities of neonatal mice of different ages to Cronobacter sakazakii infection. Timed-pregnant CD-1 mice were allowed to give birth naturally. Neonatal mice were orally gavaged at postnatal days (PNDs) 1.5, 5.5, and 9.5 with a single dose of vehicle or 10(3), 10(7), or 10(10) CFU/ml C. sakazakii strain MNW2 in reconstituted powdered infant formula. Pups were euthanized 7 days after challenge. Brains, livers, and ceca were excised and analyzed for C. sakazakii invasion, and blood was collected for serum amyloid A analysis as a biomarker of infection. C. sakazakii invasion was age dependent; the pathogen was isolated from brains, livers, and ceca of neonatal mice treated at PNDs 1.5 and 5.5 but not from those of pups treated at PND 9.5. C. sakazakii was more invasive at PND 1.5 in brains than in livers and ceca and was isolated from 22, 14, and 18% of these tissue samples, respectively. Serum amyloid A was detected in only one treated neonate. Mortality was observed only in neonates treated at PND 1.5. In conclusion, neonatal mice had a time-dependent susceptibility to C. sakazakii infection, with resistance increasing with increasing age.     

A steady-state biofilm model for simultaneous reduction of nitrate and perchlorate, part 2: parameter optimization and results and discussion

Part 1 of this work developed a steady-state, multispecies biofilm model for simultaneous reduction of nitrate and perchlorate in the H(2)-based membrane biofilm reactor (MBfR) and presented a novel method to solve it. In Part 2, the half-maximum-rate concentrations and inhibition coefficients of nitrate and perchlorate are optimized by fitting data from experiments with different combinations of influent nitrate and perchlorate concentrations. The model with optimized parameters is used to quantitatively and systematically explain how three important operating conditions (nitrate loading, perchlorate loading, and H(2) pressure) affect nitrate and perchlorate reduction and biomass distribution in these reducing biofilms. Perchlorate reduction and accumulation of perchlorate-reducing bacteria (PRB) in the biofilm are affected by four promotion or inhibition mechanisms: simultaneous use of nitrate and perchlorate by PRB and competition for H(2), the same resources in PRB, and space in a biofilm. For the hydrogen pressure evaluated experimentally, a low nitrate loading (<0.1 g N/m(2)-d) slightly promotes perchlorate removal, because of the beneficial effect from PRB using both acceptors. However, a nitrate loading of >0.6 g N/m(2)-d begins to inhibit perchlorate removal, as the competition effects become dominant.     

Short communication: Prepartum plasma insulin-like growth factor-I concentrations based on day of insemination are lower in cows developing postpartum diseases

Because peripartal production diseases are prevalent in dairy cows, early recognition is crucial. Several studies reported metabolic variables as risk predictors for subsequent diseases. To improve on-farm testing and application of those methods, the sampling procedure should take into account variation in gestation length. Furthermore, additional variables indicating cows at risk of any production disease should be sought. Therefore, the objective was to characterize differences between cows with and without postpartum production disease (retained fetal membranes, ketosis, hypocalcemia, abomasal displacement, metritis, mastitis) by prepartum measurement of serum nonesterified fatty acid (NEFA) and plasma insulin-like growth factor (IGF)-I concentrations relative to the artificial insemination (AI) that established pregnancy. Blood was collected from 41 Holstein Friesian cows on 235 to 241, 242 to 248, 249 to 255, 256 to 262, 263 to 269, 270 to 276, 277 to 283, and 284 to 290 d after AI. Health status was assessed daily for 3 wk after calving; 25 cows (66%) had at least one production disease. Cows developing postpartum diseases had higher mean serum NEFA concentrations (450 ± 26 μmol/L; mean ± SE) and lower plasma IGF-I concentrations (78 ± 6 ng/mL) prepartum compared with healthy cows (259 ± 19 μmol/L and 117 ± 8 ng/mL, respectively). In conclusion, because of substantial variation among cows in gestation length, blood samples should be collected and studies performed on risk prediction relative to AI rather than expected date of calving. As the somatotropic axis is one of the key regulators of metabolic adaption for onset of lactation, IGF-I might be a useful variable to differentiate between cows susceptible to production diseases and cows that are able to adapt adequately within the transition period and remain healthy.     

Evaluating an intervention to reduce lameness in dairy cattle

Lameness in dairy cattle remains a significant welfare concern for the UK dairy industry. Farms were recruited into a 3-yr study evaluating novel intervention approaches designed to encourage farmers to implement husbandry changes targeted toward reducing lameness. All farms completing the study were visited at least annually and received either monitoring only (MO, n=72) or monitoring and additional support (MS, n = 117) from the research team. The additional support included traditional technical advice on farm-specific solutions, facilitation techniques to encourage farmer participation, and application of social marketing principles to promote implementation of change. Lameness prevalence was lower in the MO (27.0 ± 1.94 SEM) and MS (21.4 ± 1.28) farms at the final visit compared with the same MO (38.9 ± 2.06) and MS (33.3 ± 1.76) farms on the initial visit. After accounting for initial lameness, intervention group status, and year of visit within a multilevel model, we observed an interaction between year and provision of support, with the reduction in lameness over time being greater in the MS group compared with the MO group. Farms in the MS group made a greater number of changes to their husbandry practices over the duration of the project (8.2 ± 0.39) compared with those farms in the MO group (6.5 ± 0.54). Because the lameness prevalence was lower in the MS group than the MO group at the start of the study, the contribution of the additional support was difficult to define. Lameness can be reduced on UK dairy farms although further work is needed to identify the optimum approaches.     

Mercury in bay bolete (Xerocomus badius): bioconcentration by fungus and assessment of element intake by humans eating fruiting bodies

Concentrations of mercury (Hg) were determined in 221 specimens of bay bolete and in 221 samples of corresponding forest topsoil layer (0-10 cm) collected from 18 sites across geographically and industrially diverse regions of Poland in 2000-2008. Mercury concentrations in caps and stipes of bay bolete were strongly correlated (p < 0.0001), whereas the relationship between the Hg concentrations in soil and mushrooms varied depending on the sampling location. The bay bolete showed a lower bioconcentration potential of Hg at sites with elevated soil Hg concentrations and a higher bioconcentration at sites with lower Hg concentrations in soil. In view of Hg content, the consumption of bay boletes (caps or whole mushrooms) at the regions surveyed at least at a rate up to 2.5 kg per capita weekly in a mushrooming season is safe and will not result in exceeding of currently allowable Hg intake doses.     

Nutrition and nutritional status in infants and children of early years of life in Russian Federation

The study of the nutrition and the nutritional status children of the first year age and children earliest age were conducted on nationally representative surveys (2500 children, 2-24 months) the Institute of Nutrition, Russian Academy of Medical Sciences with the Institute of Sociology Russian of Academy of Sciences, Gerber Product Company and Nestle Company in 2006. The level the frequency of breast feeding had among children 1 m.--80%, 2-4 m.--70%, 4-6 m.--60%. The lowest body mass Z-scores were registered 0.5-5.0% among of children, the tendency of obesity increase in the age were registered from 1.6 to 13% of children. Calculations of chemical composition and energy value of actual nutrition have show according to the values requirements.     

Raman spectroscopy of graphene and bilayer under biaxial strain: bubbles and balloons

We use graphene bubbles to study the Raman spectrum of graphene under biaxial (e.g., isotropic) strain. Our Gruneisen parameters are in excellent agreement with the theoretical values. Discrepancy in the previously reported values is attributed to the interaction of graphene with the substrate. Bilayer balloons (intentionally pressurized membranes) have been used to avoid the effect of the substrate and to study the dependence of strain on the interlayer interactions.     

How close can one approach the dirac point in graphene experimentally?

The above question is frequently asked by theorists who are interested in graphene as a model system, especially in context of relativistic quantum physics. We offer an experimental answer by describing electron transport in suspended devices with carrier mobilities of several 10(6) cm(2) V(-1) s(-1) and with the onset of Landau quantization occurring in fields below 5 mT. The observed charge inhomogeneity is as low as ≈10(8) cm(-2), allowing a neutral state with a few charge carriers per entire micrometer-scale device. Above liquid helium temperatures, the electronic properties of such devices are intrinsic, being governed by thermal excitations only. This yields that the Dirac point can be approached within 1 meV, a limit currently set by the remaining charge inhomogeneity. No sign of an insulating state is observed down to 1 K, which establishes the upper limit on a possible bandgap.     

Synthesis, growth mechanism and characterization of single crystalline alpha-Fe2O3 spherical nanoparticles

In the present report, we proposed a simple and efficient method for synthesizing single crystalline alpha-Fe2O3 spherical nanoparticles array into hexagonal dipyramid (HGDP) hierarchical structures using urea as a surface-active agent to control the growth and nucleation of the iron species. Growth mechanisms for the formation of HGDP hierarchical structures have been also proposed. Single crystalline feature, structural morphology and size of the nanoparticles were investigated by X-ray diffraction (XRD), Scanning and Transmission electron microscopy (SEM). The spectroscopic techniques such as; FT-IR, UV-VIS absorption and Raman spectroscopy were used to investigate optical response of the synthesized nanoparticles. Optical energy band gap was calculated to be 2.57 eV and 2.21 eV corresponding to direct and indirect transitions, respectively. The magnetic properties of the single crystalline nanoparticle were also investigated by Vibrating sample magnetometer (VSM) and found that they are weak ferromagnetic in nature. The values of saturation magnetization, remanent magnetization and coercivity were found to be 0.5925 emu/g and 0.1642 emu/g and approximately 1650 Oe, respectively.     

Atomic structural analysis of nanowire defects and polytypes enabled through cross-sectional lattice imaging

Correlated transmission electron microscopy imaging, electron diffraction, and Raman spectroscopy are used to investigate the structure of Si nanowires with planar defects. In addition to plan‐view imaging, individual defective nanowires are imaged in axial cross‐section at specific locations selected in plan‐view imaging. This correlated characterization approach enables definitive identification of complex defect structures that give rise to diffraction patterns that have been misinterpreted in the literature. Conclusive evidence for the 9R Si polytype is presented, and the atomic structure of this phase is correlated with kinematically‐forbidden reflections in Si diffraction patterns. Despite striking similarities between imaging and diffraction data from twinned nanowires and the 9R polytype, clear distinctions between the structures can be made. Finally, the structural origins of ?{422} reflections in Si [111] diffraction patterns are identified.