Vibrational phase relaxation of O–H stretch in bulk water: Role of large amplitude angular jumps and negative cross-correlations among the forces on the O–H bond

The ultrafast vibrational phase relaxation of O–H stretch in bulk water is investigated in molecular dynamics simulations. The dephasing time (T₂) of the O–H stretch in bulk water calculated from the frequency fluctuation time correlation function (C_ω(t)) is in the range of 70–80 femtosecond (fs), which is comparable to the characteristic timescale obtained from the vibrational echo peak shift measurements using infrared photon echo [W.P. de Boeij, M.S. Pshenichnikov, D.A. Wiersma, Ann. Rev. Phys. Chem. 49 (1998) 99]. The ultrafast decay of C_ω(t) is found to be responsible for the ultrashort T₂ in bulk water. Careful analysis reveals the following two interesting reasons for the ultrafast decay of C_ω(t). (A) The large amplitude angular jumps of water molecules (within 30–40 fs time duration) provide a large scale contribution to the mean square vibrational frequency fluctuation and gives rise to the rapid spectral diffusion on 100 fs time scale. (B) The projected force, due to all the atoms of the solvent molecules on the oxygen (F_O(t)) and hydrogen (F_H(t)) atom of the O–H bond exhibit a large negative cross-correlation (NCC). We further find that this NCC is partly responsible for a weak, non-Arrhenius temperature dependence of the dephasing rate.     

Quantization dimension for infinite self-similar probabilities

The quantization dimension function for a probability measure induced by a set of infinite contractive similarity mappings and a given probability vector is determined. A relationship between the quantization dimension function and the temperature function of the thermodynamic formalism arising in multifractal analysis is established. The result in this paper is an infinite extension of Graf and Luschgy [S. Graf, H. Luschgy, The quantization dimension of self-similar probabilities, Math. Nachr. 241 (2002) 103-109].     

Superb hydroxyl radical-mediated biocidal effect induced antibacterial activity of tuned ZnO/chitosan type II heterostructure under dark

Journal of Nanoparticle Research - With the widespread use of titanium dioxide (TiO2) human exposure is inevitable, but the exposure data on TiO2 are still limited. This study adopted off-line...     

On the formation of shock and soliton in a dense quantum dusty plasma with cylindrical geometry

Excitation of nonlinear waves in a quantum dusty plasma with various effects is analyzed when the geometry is cylindrical.This introduces the effect of finite boundary conditions on the solitary waves so generated. it is observed that the nonlinear equation deduced is cylindrical KP–Burger type leading to the generation of Shock Wave. Different situations which arises in various parameter regions are considered separately and the form of the nonlinear excitations are obtained explicitly.     

Any two irreducible Markov chains of equal entropy are finitarily Kakutani equivalent

We show here that any two finite state irreducible Markov chains of the same entropy are finitarily Kakutani equivalent. By this we mean they are orbit equivalent by an invertible measure preserving mapping that is almost continuous and monotone in time when restricted to some cylinder set. Smorodinsky and Keane have shown that any two irreducible Markov chains of equal entropy and period are finitarily isomorphic. Hence, all that is necessary to obtain our result is to show that for every entropy h > 0 and period p ∈ ℕ there exists two irreducible Markov chains σ ₁, σ ₂ both of entropy h, where (1) σ ₁ is mixing (2) ς ₂ has period p and (3) σ1 and σ ₂ are finitarily Kakutani equivalent.     

A rapid and sensitive determination of hypoxic radiosensitizer agent nimorazole in rat plasma by LC‐MS/MS and its application to a pharmacokinetic study

A highly sensitive, accurate and robust LC‐MS/MS method was developed and validated for determination of nimorazole (NMZ) in rat plasma using metronidazole (MNZ) as internal standard (IS). The analyte and IS were extracted from plasma by precipitating protein with acetonitrile and were chromatographed using an Agilent Poroshell 120, EC‐C₁₈ column. The mobile phase was composed of a mixture of acetonitrile and 0.1 % formic acid (85:15 v/v). The total run time was 1.5 min and injection volume was 5 μL. Multiple reaction monitoring mode using the transitions of m/z 227.1 → m/z 114.0 for MNZ and m/z 172.10 → m/z 128.1 for IS were monitored on a triple quadrupole mass spectrometer, operating in positive ion mode. The calibration curve was linear in the range of 0.25–200 ng/mL (r² > 0.9996) and the lower limit of quantification was 0.25 ng/mL in the rat plasma samples. Recoveries of NMZ ranged between 88.05 and 95.25%. The precision (intra‐day and inter‐day) and accuracy of the quality control samples were 1.25–8.20% and ?2.50–3.10, respectively. The analyte and IS were found to be stable during all sample storage and analysis procedures. The LC‐MS/MS method described here was validated and successfully applied to pharmacokinetic study in rats. Copyright © 2015 John Wiley & Sons, Ltd.     

On Structured Surfaces with Defects: Geometry,Strain Incompatibility,Stress Field,and Natural Shapes

In this paper we study the stress and deformation fields generated by nonlinear inclusions with finite eigenstrains in anisotropic solids. In particular, we consider finite eigenstrains in transversely isotropic spherical balls and orthotropic cylindrical bars made of both compressible and incompressible solids. We show that the stress field in a spherical inclusion with uniform pure dilatational eigenstrain in a spherical ball made of an incompressible transversely isotropic solid such that the material preferred direction is radial at any point is uniform and hydrostatic. Similarly, the stress in a cylindrical inclusion contained in an incompressible orthotropic cylindrical bar is uniform hydrostatic if the radial and circumferential eigenstrains are equal and the axial stretch is equal to a value determined by the axial eigenstrain. We also prove that for a compressible isotropic spherical ball and a cylindrical bar containing a spherical and a cylindrical inclusion, respectively, with uniform eigenstrains the stress in the inclusion is uniform (and hydrostatic for the spherical inclusion) if the radial and circumferential eigenstrains are equal. For compressible transversely isotropic and orthotropic solids, we show that the stress field in an inclusion with uniform eigenstrain is not uniform, in general. Nevertheless, in some special cases the material can be designed in order to maintain a uniform stress field in the inclusion. As particular examples to investigate such special cases, we consider compressible Mooney-Rivlin and Blatz-Ko reinforced models and find analytical expressions for the stress field in the inclusion.