Magnetic-field induced multiferroicity in a quantum critical frustrated spin liquid

Dielectric spectroscopy is used to check for the onset of polar order in the quasi one-dimensional quantum spin system Sul-Cu2Cl4 when passing from the spin-liquid state into the ordered spiral phase in an external magnetic field. We find clear evidence for multiferroicity in this material and treat in detail its H-T phase diagram close to the quantum-critical regime.Comment: 5 pages, 4 figures. Revised according to suggestions of referee

Electron spin resonance study of anisotropic interactions in a two-dimensional spin gap magnet PHCC

Fine details of the excitation spectrum of the two-dimensional spin-gap magnet PHCC are revealed by electron spin resonance investigations. The values of anisotropy parameters and the orientations of the anisotropy axes are determined by accurate measurements of the angular, frequency-field and temperature dependences of the resonance absorption. The properties of a spin-gap magnet in the vicinity of critical field are discussed in terms of sublevel splittings and g-factor anisotropy.Comment: submitted to PR

Influence of Fruit Juice From Aronia Melanocarpa on the Process of Lipid Peroxidation in a Model of Carbon Tetrachloride-Induced Hepatotoxicity in Rats

The fruit juice from Aronia melanocarpa (FJAM) is rich in anthocyanins. We studied the effect of FJAM on the process of lipid peroxidation in a model of carbon tetrachloride (CCI4)-induced hepatotoxicity in rats. Malondialdehyde (MDA) levels were measured in plasma and liver homogenate. CCU induced a significant elevation of MDA levels in the plasma (p<0,05) and in the homogenate (p<0,01) in comparison with distilled water-treated controls. FJAM applied alone did not significantly influence on the MDA levels. The pretreatment of the rats with FJAM before their treatment with CCI4 lead dose-dependently to MDA levels in the plasma and homogenate which did not differ in most animal groups from the controls and were significantly lower from those of the CCI4-treated rats

Long-lived magnons throughout the Brillouin zone of the strong-leg spin ladder (C7_7H10_{10}N)2_2CuBr4_4

Inelastic neutron scattering is used to measure spin excitations in fully deuterated single crystal samples of the strong-leg antiferromagnetic S=1/2 spin ladder compound (C$_7$H$_{10}$N)$_2$CuBr$_4$. Sharp resolution-limited magnons are observed across the entire one-dimensional Brillouin zone. The results validate the previously proposed {\it symmetric} spin ladder model and provide a reliable estimate of the relevant exchange interactions.Comment: 5 pages, 5 figure

On fatigue behaviour of two spring steels. Part II: Mathematical models

Symmetric fatigue in two spring steels is investigated in three groups of specimens. One of the groups (Steel EN10270-1SH/ DIN 17223C – C 0.82%, Mn 0.76%, Si 0.26%) has experienced rotating-bending fatigue in air, and the other two groups (Steel BS250A53/ DIN 55Si7 – C 0.56%, Mn 0.81%, Si 1.85%), torsion fatigue in-air and corrosion environment. All experiments include testing to fracture, applying acetate-foil replication technique, replica monitoring of short crack surface growth, length measuring of propagating cracks, a, at the corresponding number of fatigue cycles, N. Data obtained from replica monitoring are presented in plots “Crack lengths, a – Cycles, N”, and used for calculating fatigue crack growth rates, da/dN, and graphical presentations “Crack growth rates, da/dN – Crack lengths, a”. A mathematical description of da/dN – a is presented by introducing a parabolic-linear model in different versions for each of the steels. The model versions are verified through comparing the experimental fatigue lifetimes with those calculated by the proposed model version

On fatigue behavior of two spring steels. Part I: Wöhler curves and fractured surfaces

Symmetric fatigue in two spring steels is investigated in three groups of specimens. One of the groups (Steel EN10270-1SH/ DIN 17223C – C 0.82%, Mn 0.76%, Si 0.26%) has experienced rotating-bending fatigue in air, and the other two groups (Steel BS250A53/ DIN 55Si7 – C 0.56%, Mn 0.81%, Si 1.85%), torsion fatigue in-air and corrosion environment. Fatigue life-time data are obtained for both spring steels, and their corresponding Wöhler curves plotted and mathematically described. Surface short fatigue cracks are observed from origin to fracture by using acetate-foil replication technique, and their length, a, measured at the corresponding number of fatigue cycles, N. Those data are presented in plots “Crack lengths, a – Cycles, N” and a comparison made between both the steels. The fractured surfaces of all specimens have been studied and analyzed by the scanning-electron microscopy method

Field-induced criticality in a gapped quantum magnet with bond disorder

Neutron diffraction and calorimetric measurements are used to study the field-induced quantum phase transition in piperazinium-Cu$_2$(Cl$_{1-x}$Br$_x$)$_6$ ($x=0$, x=3.5% and x=7.5%), a prototypical quantum antiferromagnet with random bonds. The critical indexes $\phi$ and $\beta$ are determined. The findings contradict some original predictions for Bose Glass based on the assumption $z=d$, but are consistent with recent theoretical results implying $z<d$. Inelastic neutron experiments reveal that disorder has a profound effect on the lowest-energy magnetic gap excitation in the system.Comment: 4.2 pages, 4 figures. Submitted to PRB Rapid Communication

The formation of oxidative disorders in the population of Vladivostok under the influence of atmospheric microparticles

We studied the response of trigger systems in healthy volunteers living in areas with different levels of air pollution. We determined that particles with the size of 800 microns and higher of relatively favorable region, particles with the size of less than 50 microns dominated in the air of the unfavorable area, among which there were the most hazardous to health amounts of microparticles - from 200 to 300 nm. Microparticles of unfavorable area causes the development of oxidative modifications of proteins and DNA contributing to the change of leukocyte potential energy. The increase in total antioxidant activity and response of thiol-disulfide system (the increase in thioredoxin, glutathione with a stable reductase level] maintains a balance of oxidation and antioxidant processes contributing to protection of the cellular and subcellular structures against considerable oxidative damage