Calcification of aortic human valves studied in situ by Raman microimaging: following mineralization from small grains to big deposits

A Raman microimaging‐based approach has been used in the current study to evaluate formation and progression of calcification in situ in human stenotic aortic valves obtained during surgical valve replacement. The capability of the method to visualize distribution of the calcified deposits resulted in structural characterization of deposits in the various phases of development. A high spatial resolution of the method along with the confocal depth profiling enabled to identify extremely small salt inclusions (of ca. 0.5 µm in diameter), formed probably at the very early stage of calcification. Structurally, these inclusions are built from an octacalcium phosphate‐like compound that during grains' growth transforms into tricalcium phosphate, mixed with the salt containing the acidic phosphate groups (HPO₄²⁻) and, finally, into stable B‐type hydroxyapatite that is the only salt present in large‐area calcium salt deposits. Copyright © 2013 John Wiley & Sons, Ltd.     

Measurement of the CP-violation parameter sin2φ1 with a new tagging method at the Υ(5S) resonance

We report a measurement of the CP-violation parameter sin2φ1 at the Υ(5S) resonance using a new tagging method, called "B-π tagging." In Υ(5S) decays containing a neutral B meson, a charged B, and a charged pion, the neutral B is reconstructed in the J/ψK(S)(0) CP-eigenstate decay channel. The initial flavor of the neutral B meson at the moment of the Υ(5S) decay is opposite to that of the charged B and may thus be inferred from the charge of the pion without reconstructing the charged B. From the asymmetry between B-π(+) and B-π(-) tagged J/ψK(S)(0) yields, we determine sin2φ1=0.57±0.58(stat)±0.06(syst). The results are based on 121 fb(-1) of data recorded by the Belle detector at the KEKB e(+)e(-) collider.     

On the Resolution Capabilities and Limits of Fluorescence Lifetime Correlation Spectroscopy (FLCS) Measurements

Quantitative tests were performed in order to explore the practical limits of FLCS. We demonstrate that: a) FLCS yields precise and correct concentration values from as low as picomolar to micromolar concentrations; b) it is possible to separate four signal components in a single detector setup; c) diffusion times differing only 25% from each other can be resolved by separating a two component mixture based on the different fluorescence lifetimes of both components; d) most of the inherent technical limitations of conventional FCS are easily overcome by FLCS employing a single detector channel confocal detection scheme.     

Beyond the Navier-Stokes equation: Including random thermal fluctuations

Dissipation and fluctuation is analyzed in discretized systems with external and internal heat bath. Discretized and continuum dissipation and fluctuation theorems are derived for both cases. It is shown that the continuum limit of the internal heat bath case leads to the Navier-Stokes equation.     

Hydrogen-induced reduction of electric field gradient in La2Fe14BHx studied by NMR on La

The ¹³⁹La NMR spin-echo spectra of La₂Fe₁₄BH_x are reported. Since lanthanum has no 4f electrons, the observed quadrupole splittings are directly proportional to the lattice part of the electric field gradient, V_zz^lat. This quantity decreases as the content of interstitial hydrogen x grows. To describe the fall-off of V_zz^lat, a dimensionless function f₂(x) is introduced, normalised so that f₂(0)=1. Analysis of the new and earlier published data obtained by several experimental techniques demonstrates that the reduction of both the second-order crystal field parameter A₂₀ and the lattice electric field gradient V_zz^lat is described by the same function f₂(x) in all R₂Fe₁₄BH_x. The only distinction that needs to be made is between R being a light and a heavy rare earth.     

Study of condensed nitrogen by μSR method

The temperature dependences of parameters of the muon spin relaxation in liquid and crystalline nitrogen have been studied. It has been established that in condensed nitrogen there takes place a fast depolarization of muons. An anomalous behaviour of the amplitude and phase of muon precession is found in the vicinity of the orientation phase transition in solid nitrogen. It has been shown that muon spin relaxation parameters in nitrogen do not change at reduction of the oxygen impurity content from 0.7·10⁻⁴ to 10⁻⁶. The fast depolarization of muons in condensed nitrogen is apparently due to the formation of muonium atoms. To explain the phenomena observed, a model of the muonium chemical reaction is proposed. The initial phase of the muon precession has been measured as a function of the perpendicular magnetic field to determine the state of short-lived muonium in nitrogen. It has been determined that muonium in nitrogen is in an excited state. Consideration of the nuclear hyperfine interaction of muonium in condensed nitrogen makes it possible to give a qualitative explanation for the temperature dependence of the initial amplitude of the muon precession.     

The influence of hydrogen on55Mn hyperfine fields in YMn2 hydrides

The NMR spin ccho measurements at 4.2 K for YMn₂H_x (x=1, 2, 3) compounds are reported. The obtained values of⁵⁵Mn hyperfine fields are analysed in dependence on the by hydrogen atoms and flips of neighbouring manganese moments. The strong increase of hyperfine field with increasing number of the nearest hydrogen atoms is explained by the change of orbital contribution to hyperfine field.