Phase transition mechanism of hexagonal graphite to hexagonal and cubic diamond:simulation.

molecular dynamics simulations are used to elucidate the mechanism of the phase transition in shock experiments from hexagonal graphite (HG) to hexagonal diamond (HD) or to cubic diamond (CD). The transition from HG to HD is found to occur swiftly in very small time of 0.2 ps, with large cooperative displacements of all the atoms.

Spin-phonon coupling and thermodynamic behaviour in YCrOand LaCrO: inelastic neutron scattering and lattice dynamics.

We report detailed temperature-dependent inelastic neutron scattering andlattice dynamics investigation of magnetic perovskites YCrOand LaCrO. The magnetic neutron scattering from the Cr ions exhibits significant changes with temperature and dominates at low momentum transfer regime.calculations performed including magnetic interactions show that the effect of magnetic interactions is very significant on the low- as well as high-energy phonon modes.

Phonons and oxygen diffusion in BiOand (BiY)O.

We report investigation of phonons and oxygen diffusion in BiOand (BiY)O. The phonon spectra have been measured in BiOat high temperatures up to 1083 K using inelastic neutron scattering.calculations have been used to compute the individual contributions of the constituent atoms in BiOand (BiY)Oto the total phonon density of states.

Atmospheric Cold Plasma and Peracetic Acid-Based Hurdle Intervention To Reduce on Raw Poultry Meat.

Atmospheric cold plasma and peracetic acid-based hurdle approach for safety of poultry products was evaluated. Study demonstrates a significant synergetic approach to reducing on raw poultry. Hurdle approach shows promising bacterial reduction but requires further optimization.

Anomalous Lattice Dynamics in AgCN: Insights From Inelastic Neutron Scattering and Density Functional Calculations.

We have performed temperature dependent inelastic neutron scattering measurements to study the anharmonicity of phonon spectra of AgCN. The analysis and interpretation of the experimental spectra is done using lattice dynamics calculations. The calculated phonon spectrum over the entire Brillouin zone is used to derive linear thermal expansion coefficients.

Phonons and Thermal Expansion Behavior of NiSi and NiGe.

We have carried out first principles calculations of the vibrational and thermodynamic behavior in NiSi and isostructural compound NiGe. Phonon density of states has also been measured in NiSi using inelastic neutron scattering techniques. We find that the vibrational spectra of the two compounds are very different, due to the difference in the size and mass of Si and Ge.

Phonons, phase transitions and thermal expansion in LiAlO: an ab initio density functional study.

We have used the ab initio density functional theory technique to understand the phase transitions and structural changes in various high temperature/pressure phases of LiAlO. The electronic band structure as well as phonon spectra is calculated for various phases as a function of pressure. The phonon entropy used for the calculations of Gibbs free energy is found to play an important role in the phase stability and phase transitions among various phases.

Removing Cross-Linked Telopeptides Enhances the Production of Low-Molecular-Weight Collagen Peptides from Spent Hens.

The low-molecular-weight (LMW) peptides derived from collagen have shown a potential for various nutritional and pharmaceutical applications. However, production of LMW peptides from vertebrate collagen remains a challenge. Herein, we report a new method to produce LMW collagen peptides using pepsin pretreatment that removed cross-linked telopeptides in collagen molecules.

Anomalous lattice behavior of vanadium pentaoxide (VO): X-ray diffraction, inelastic neutron scattering and ab initio lattice dynamics.

We present structural and dynamical studies of layered vanadium pentaoxide (VO). The temperature dependent X-ray diffraction measurements reveal highly anisotropic and anomalous thermal expansion from 12 K to 853 K. The results do not show any evidence of structural phase transition or decomposition of α-VO, contrary to the previous transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) experiments.

Superionic conduction in β-eucryptite: inelastic neutron scattering and computational studies.

β-Eucryptite (LiAlSiO) is known to show super-ionic conductivity above 700 K. We performed inelastic neutron scattering measurements in β-eucryptite over 300-900 K and calculated the phonon spectrum using classical molecular dynamics (MD) simulations. The MD simulations were used to interpret the inelastic neutron spectra at high temperatures.

Investigating anomalous thermal expansion of copper halides by inelastic neutron scattering and ab initio phonon calculations.

We investigate the detailed lattice dynamics of copper halides, CuX (X = Cl, Br, and I), using neutron inelastic scattering measurements and ab initio calculations aimed at a comparative study of their thermal expansion behavior. We identify the low energy phonons which soften with pressure and are responsible for negative thermal expansion. The eigenvector analysis of these modes suggests that softening of the transverse-acoustic modes would lead to NTE in these compounds.

New insights into the compressibility and high-pressure stability of Ni(CN)2: a combined study of neutron diffraction, Raman spectroscopy, and inelastic neutron scattering.

Nickel cyanide is a layered material showing markedly anisotropic behaviour. High-pressure neutron diffraction measurements show that at pressures up to 20.1 kbar, compressibility is much higher in the direction perpendicular to the layers, c, than in the plane of the strongly chemically bonded metal-cyanide sheets.

Dendrimers for gene delivery--a potential approach for ocular therapy?

Objectives: A vast number of blinding diseases have genetic aetiologies and may be treated by molecular based therapies such as antisense oligonucleotides or short interfering RNA. However, treatment success of ocular gene therapy is highly dependent on efficient delivery of such molecules.

Key Findings: The majority of clinical studies for ocular gene therapy utilize viral vectors.

Phonons and colossal thermal expansion behavior of Ag3Co(CN)6 and Ag3Fe(CN)6.

Recently colossal volume thermal expansion has been observed in the framework compounds Ag(3)Co(CN)(6) and Ag(3)Fe(CN)(6). We have measured phonon spectra using neutron time-of-flight spectroscopy as a function of temperature and pressure. Ab initio calculations were carried out for the sake of analysis and interpretation.

Vibrational properties and phase transitions in II-VI materials: lattice dynamics, ab initio studies and inelastic neutron scattering measurements.

Inelastic neutron scattering measurements were carried out to determine the phonon density of states of ZnSe and interpreted with lattice dynamical computations (ab initio as well as a potential model). Calculations are also reported for other II-VI compounds, ZnTe and ZnS. Vibrational (phonon spectra and Grüneisen parameters), and thermal (negative thermal expansion and non-Debye specific heat) properties have been calculated and found to be in good agreement with available experimental data.

Magnetic lattice dynamics of the oxygen-free FeAs pnictides: how sensitive are phonons to magnetic ordering?

To shed light on the role of magnetism on the superconducting mechanism of the oxygen-free FeAs pnictides, we investigate the effect of magnetic ordering on phonon dynamics in the low-temperature orthorhombic parent compounds, which present a spin density wave. The study covers both the 122 (AFe(2)As(2); A = Ca, Sr, Ba) and 1111 (AFeAsF; A = Ca, Sr) phases. We extend our recent work on the Ca (122 and 1111) and Ba (122) cases by treating, computationally and experimentally, the 122 and 1111 Sr compounds.

Lattice dynamics and Born instability in yttrium aluminum garnet, Y3Al5O12.

We report lattice dynamics calculations of various microscopic and macroscopic vibrational and thermodynamic properties of yttrium aluminum garnet (YAG), Y3Al5O12, as a function of pressure up to 100 GPa and temperature up to 1500 K. YAG is an important solid-state laser material with several technological applications. Garnet has a complex structure with several interconnected dodecahedra, octahedra and tetrahedra.

Lattice dynamics of orthorhombic perovskite yttrium manganite, YMnO(3).

The lattice dynamics of yttrium manganite (YMnO(3)) has been investigated by means of a shell model with pair-wise interionic interaction potential. The experimental data of crystal structure and Raman and infrared frequencies compare well with the lattice dynamical calculations. The phonon dispersion curves found along three high symmetry directions and the density of states of YMnO(3) have also been calculated from this model.

Measurement of anomalous phonon dispersion of CaFe2As2 single crystals using inelastic neutron scattering.

We measured phonon dispersions of CaFe2As2 using inelastic neutron scattering and compared our results to predictions of density functional theory in the local density approximation. The calculation gives correct frequencies of most phonons if the experimental crystal structure is used, except observed linewidths/frequencies of certain modes were larger/softer than predicted. Strong temperature dependence of some phonons near the structural phase transition near 172 K may indicate strong electron-phonon coupling and/or anharmonicity, which may be important for superconductivity.

Dynamics of adsorbed hydrocarbon in nanoporous zeolite framework.

We report quasielastic neutron scattering (QENS) and molecular dynamics (MD) simulation study of the dynamics of propylene molecules adsorbed in Na-ZSM5 zeolite. MD simulation studies suggest that rotational motion is almost an order of magnitude faster than translational motion. Therefore, spectrometers having different energy resolutions were used to determine the translational and rotational contributions.

Dynamics of 1,3-butadiene adsorbed in Na-Y zeolite: a molecular dynamics simulation study.

Here we report dynamics of 1,3-butadiene molecules adsorbed in Na-Y zeolite as studied using molecular dynamics (MD) simulations. The results showed that the translational motion of the guest molecule exists in three different time scales one of which matches well with the quasielastic neutron scattering (QENS) measurement reported earlier. The translational motion in the component, which has been measured by QENS, is found to occur through discrete jumps, in agreement with the analysis of the experiments.

Stress-induced changes in sleep and associated neuronal activity in rat hippocampus and amygdala.

Stress increases vulnerability to anxiety and depression. We have investigated the effect of acute immobilization stress in amygdalohippocampal circuits by measuring the electroencephalogram (EEG) in male Wistar rats during rapid eye movement (REM) sleep. Electrodes were implanted stereotaxically in the hippocampus (CA1 and CA3 subregions of the hippocampus) and the amygdala (lateral nucleus).

Diffusion of acetylene inside Na-Y zeolite: molecular dynamics simulation studies.

Dynamics of acetylene molecules adsorbed in Na-Y zeolite cages is investigated using molecular dynamics simulation. The translational motion of the acetylene molecules is shown to involve three different time scales. "Free particle" type diffusion is observed in short time and small length scale.