Thermodesorption of impurities from detonation nanodiamond

The molecular composition of volatile compounds belonging to the impurity subsystem of detonation nanodiamond particles has been analyzed. It is established that the main volatile impurities are water, hydrogen, nitrogen, methane, carbon dioxide, and sulfur dioxide. In the course of annealing, the concentration of these volatile impurities exhibits a significant decrease, the sample weight loss reaching up to 20%. This process is accompanied by both endo- and exothermal effects.     

Hydrogenation properties of Hf-Ni intermetallics - Experimental and theoretical investigation

The hydrogenation properties of HfNi and Hf₂Ni₇ intermetallics were investigated at the constant pressure of 1 bar and in the temperature ranges 373-573 K for HfNi and 323-473 K for Hf₂Ni₇. The kinetic parameters, rate constants and activation energies of the absorption processes were determined. Maximal hydrogen absorption, i.e., number of hydrogen atoms absorbed per metal atom, H/M, are 1.05 and 0.04 achieved at 373 K for HfNi and Hf₂Ni₇, respectively. Multiple hydriding/dehydriding was found to influence the improvement of the kinetic parameters. XRD and SEM methods were used to investigate the structural and morphological changes of the samples due to hydrogen absorption. The thermodynamic parameters of hydriding together with the structural properties of the intermetallics and their hydrides, calculated using the full-potential linearized augmented plane waves (FP-LAPW) code based on the density functional theory (DFT), were utilized for the sake of explaining the experimental investigations.     

Formation of spectral characteristics of channeling radiation from 800 to 2000 MeV electrons and positrons in a thin silicon crystal

The influence of the tails of particle trajectories on planar channeling radiation (CR) spectra from relativistic (800-2000 MeV) electrons and positrons in a thin silicon crystal is investigated. It is shown that the trajectory tails significantly change the CR spectra from electrons and positrons in specific parts of the spectra compared to calculations which do not take into account this effect.     

Calculation of the thermodynamic interaction parameter ρ C C,Ni , in the austenite of the Fe-C-Ni system

In the study, the interaction model has been considered, which assumes that the radius of interaction between carbon and nickel atoms in austenite corresponds to the nearest neighborhood of an octahedral interstice by lattice sites, and the interaction radius between two carbon atoms corresponds to two nearest coordination shells formed by octahedral interstices in the lattice. The three-particle potential of approach of C-Ni-C atoms is taken equal to zero. The pair potential of interaction between carbon atoms in austenite is taken to be equal to that obtained from the data of Mössbauer spectroscopy. In this model, the magnitude of the secondorder thermodynamic cross-interaction parameter ρ _C ^{C, Ni} in the austenite at a temperature of 1273 K has been calculated. The results of the calculation (ρ _C ^{C, Ni} = 11.4) satisfactorily agree with the experimental value (ρ _C ^{C, Ni} = 11.1).     

Early Postoperative Immunothrombosis of Bioprosthetic Mitral Valve and Left Atrium: A Case Report

A 72-year-old female patient with mixed rheumatic mitral valve disease and persistent atrial fibrillation underwent mitral valve replacement and suffered from a combined thrombosis of the bioprosthetic valve and the left atrium as soon as 2 days post operation. The patient immediately underwent repeated valve replacement and left atrial thrombectomy. Yet, four days later the patient died due to the recurrent prosthetic valve and left atrial thrombosis which both resulted in an extremely low cardiac output. In this patient’s case, the thrombosis was notable for the resistance to anticoagulant therapy as well as for aggressive neutrophil infiltration and release of neutrophil extracellular traps (NETs) within the clot, as demonstrated by immunostaining. The reasons behind these phenomena remained unclear, as no signs of sepsis or contamination of the BHV were documented, although the patient was diagnosed with inherited thrombophilia that could impede the fibrinolysis. The described case highlights the hazard of immunothrombosis upon valve replacement and elucidates its mechanisms in this surgical setting.     

Interfacing of a Coordinate-Sensitive Detector Based on Charge-Coupled Devices for Recording Ions with a Portable Static Mass Spectrograph

An IDS 2030 IonCCD coordinate-sensitive detector (Analytical/CMS Field Products) is interfaced with a small-sized mass spectrograph developed at the Ioffe Physical Technical Institute, Russian Academy of Sciences. The measurement data obtained with the mass spectrograph using an IonCCD detector and a Magnum-5901-37029PS channel secondary electron multiplier (Photonics USA Inc., United States) are compared. The results of measurements are discussed, and the prospects for using the IonCCD coupled with a microchannel plate are assessed.     

A Pilot Study of Changes in the Level of Catecholamines and the Activity of α-2-Macroglobulin in the Tear Fluid of Patients with Parkinson’s Disease and Parkinsonian Mice

Development of differential and early (preclinical) diagnostics of Parkinson’s disease (PD) is among the priorities in neuroscience. We searched for changes in the level of catecholamines and α-2-macroglobulin activity in the tear fluid (TF) in PD patients at an early clinical stage. It was shown that TF in patients is characterized by an increased level of noradrenaline mainly on the ipsilateral side of pronounced motor symptoms (72%, p = 0.049), a decreased level of adrenaline on both sides (ipsilateral—53%, p = 0.004; contralateral—42%, p = 0.02), and an increased α-2-macroglobulin activity on both sides (ipsilateral—53%, p = 0.03; contralateral—56%, p = 0.037) compared to controls. These changes are considered as potential biomarkers for differential diagnosis. Similar changes in the TF were found in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice when modeling clinical and preclinical stages of PD. These data show the adequacy of models to the pathogenesis of PD along the selected metabolic pathways, and also suggest that the found TF changes can be considered as potential biomarkers for preclinical diagnosis of PD. In Parkinsonian mice, the level of catecholamines also changes in the lacrimal glands, which makes it possible to consider them as one of the sources of catecholamines in the TF.     

Thermomechanical Properties and Structure of Fluorophosphate Glasses Activated with Nd3+ at Different Concentrations of Ba(PO3)2

Glass Physics and Chemistry - The system xBa(PO3)2·(99 – x)(AlF3–BaF2–CaF2–MgF2–SrF2)–1NdF3, where x = 2, 5, 10, 15, 20, 30, and 40 mol %, is considered....