Transport and Magnetic Studies of New Mixed-Valence Compounds: K3Cu8Se6, KCu3Se2, K3Cu8Te6 and BaCuS3-x

New mixed-valent copper chalcogenides BaCuS3_x and K3Cu8X6 with X = Se or Te and KCu3Se2, with chemical patterns corresponding to the recently investigated K3Cu8S6 and KCu3S2, were synthesized. For these new samples the results of resistivity and magnetic susceptibility measurements are presented. For BaCuS3_x, K3Cu8Se6 and KCu3Se2 the metal—insulator transition is observed with the low temperature phase being metallic, which is untypical, whereas K3Cu8Te6 is a metal in the investigated temperature range. The temperature dependence of magnetic susceptibility of the studied samples testifies to their diamagnetic or weakly paramagnetic behaviour

Double‐needle yamane technique using flanged haptics in ocular trauma—a retrospective survey of visual outcomes and safety

To evaluate visual outcomes and safety of the double‐needle technique using flanged haptics (Yamane technique) in patients with aphakia caused by ocular trauma at a trauma referral center. Retrospective: Consecutive interventional case series of 30 patients who underwent the Yamane technique due to posttraumatic aphakia. The double‐needle technique using flanged haptics was combined with anterior vitrectomy (group A) in 14 patients, and with pars plana vitrectomy (PPV) (group B) due to retinal detachment, nucleus dislocation into the vitreous cavity, or intraocular lens (IOL) displacement in 16 patients. No intraoperative complications were noted. There was significant improvement in the visual acuity in both groups at the second postoperative visit. However, the visual acuity was significantly worse in the group treated with the Yamane technique combined with PPV. Silicone oil tamponade in PPV group was associated with worse visual acuity, whereas post lensectomy status was associated with poor visual function result in the anterior vitrectomy group. There was one case of slight IOL decentration and one retinal detachment during the postoperative follow‐up period in the group with PPV. In this case series, the Yamane technique applied in traumatized eyes was found to be an efficacious and safe procedure. Combining the Yamane technique with PPV due to posterior segment ocular trauma was associated with worse functional results in the follow‐up at three months. Further studies with longer follow‐up evaluations are required to verify long‐term complications

Generalized kinetic and evolution equations in the approach of the nonequilibrium statistical operator

The method of the nonequilibrium statistical operator developed by D. N. Zubarev is employed to analyse and derive generalized transport and kinetic equations. The degrees of freedom in solids can often be represented as a few interacting subsystems (electrons, spins, phonons, nuclear spins, etc.). Perturbation of one subsystem may produce a nonequilibrium state which is then relaxed to an equilibrium state due to the interaction between particles or with a thermal bath. The generalized kinetic equations were derived for a system weakly coupled to a thermal bath to elucidate the nature of transport and relaxation processes. It was shown that the "collision term" had the same functional form as for the generalized kinetic equations for the system with small interactions among particles. The applicability of the general formalism to physically relevant situations is investigated. It is shown that some known generalized kinetic equations (e.g. kinetic equation for magnons, Peierls equation for phonons) naturally emerges within the NSO formalism. The relaxation of a small dynamic subsystem in contact with a thermal bath is considered on the basis of the derived equations. The Schrodinger-type equation for the average amplitude describing the energy shift and damping of a particle in a thermal bath and the coupled kinetic equation describing the dynamic and statistical aspects of the motion are derived and analysed. The equations derived can help in the understanding of the origin of irreversible behavior in quantum phenomena.Comment: 21 pages, Revte

Trimethylamine, a gut bacteria metabolite and air pollutant, increases blood pressure and markers of kidney damage including proteinuria and KIM-1 in rats

BACKGROUND: Trimethylamine oxide (TMAO) is a biomarker in cardiovascular and renal diseases. TMAO originates from the oxidation of trimethylamine (TMA), a product of gut microbiota and manufacturing industries-derived pollutant, by flavin monooxygenases (FMOs). The effect of chronic exposure to TMA on cardiovascular and renal systems is undetermined. METHODS: Metabolic, hemodynamic, echocardiographic, biochemical and histopathological evaluations were performed in 12-week-old male SPRD rats receiving water (controls) or TMA (200 or 500 µM/day) in water for 18 weeks. TMA and TMAO levels, the expression of FMOs and renin-angiotensin system (RAS) genes were evaluated in various tissues. RESULTS: In comparison to controls, rats receiving high dose of TMA had significantly increased arterial systolic blood pressure (126.3 ± 11.4 vs 151.2 ± 19.9 mmHg; P = 0.01), urine protein to creatinine ratio (1.6 (1.5; 2.8) vs 3.4 (3.3; 4.2); P = 0.01), urine KIM-1 levels (2338.3 ± 732.0 vs. 3519.0 ± 953.0 pg/mL; P = 0.01), and hypertrophy of the tunica media of arteries and arterioles (36.61 ± 0.15 vs 45.05 ± 2.90 µm, P = 0.001 and 18.44 ± 0.62 vs 23.79 ± 2.60 µm, P = 0.006; respectively). Mild degeneration of renal bodies with glomerulosclerosis was also observed. There was no significant difference between the three groups in body weight, water-electrolyte balance, echocardiographic parameters and RAS expression. TMA groups had marginally increased 24 h TMA urine excretion, whereas serum levels and 24 h TMAO urine excretion were increased up to 24-fold, and significantly increased TMAO levels in the liver, kidneys and heart. TMA groups had lower FMOs expression in the kidneys. CONCLUSIONS: Chronic exposure to TMA increases blood pressure and increases markers of kidney damage, including proteinuria and KIM-1. TMA is rapidly oxidized to TMAO in rats, which may limit the toxic effects of TMA on other organs. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12967-022-03687-y

Statistical Theory of Spin Relaxation and Diffusion in Solids

A comprehensive theoretical description is given for the spin relaxation and diffusion in solids. The formulation is made in a general statistical-mechanical way. The method of the nonequilibrium statistical operator (NSO) developed by D. N. Zubarev is employed to analyze a relaxation dynamics of a spin subsystem. Perturbation of this subsystem in solids may produce a nonequilibrium state which is then relaxed to an equilibrium state due to the interaction between the particles or with a thermal bath (lattice). The generalized kinetic equations were derived previously for a system weakly coupled to a thermal bath to elucidate the nature of transport and relaxation processes. In this paper, these results are used to describe the relaxation and diffusion of nuclear spins in solids. The aim is to formulate a successive and coherent microscopic description of the nuclear magnetic relaxation and diffusion in solids. The nuclear spin-lattice relaxation is considered and the Gorter relation is derived. As an example, a theory of spin diffusion of the nuclear magnetic moment in dilute alloys (like Cu-Mn) is developed. It is shown that due to the dipolar interaction between host nuclear spins and impurity spins, a nonuniform distribution in the host nuclear spin system will occur and consequently the macroscopic relaxation time will be strongly determined by the spin diffusion. The explicit expressions for the relaxation time in certain physically relevant cases are given.Comment: 41 pages, 119 Refs. Corrected typos, added reference

IR Studies of the Phase Transformation of Fe2O3 → Fe3O4by Magnetomechanical Activation

The phase transformation of hematite αFe2O3 into magnetite Fe3O4 during wet milling in vacuum as a result of mechanochemical process has been investigated by infrared spectroscopy. The FTIR spectra were recorded in the wavenumber range kom 400 to 4000 cm-1. Two very strong bands were generally observed : one in the range 557-577cm-1 with shoulders in 632-693 cm-1, the other at about 475 cm-1. The most important feature is a very strong dependence of the intensities of the main absorption bands on the milling time of the sample. In addition, there was a broad band in the 3000-3700 cm-1 region related to the appearance of a certain number of OH groups in the spinel lattice. The results are discussed assuming the theoretically indicated active IR modes for ferites. A little disorded was interpreted as generated by ball milling and no traces of amorphization were observed

Some Electronic Properties of Sr1−x\text{}_{1-x}Ax\text{}_{x}CuO2+δ\text{}_{2+δ} where A=La, K, and Ca

The electronic properties of Sr$\text{}_{1-x}$A$\text{}_{x}$CuO$\text{}_{2+δ}$ (A = La, K, Ca) were examined. The crystal structure of the synthesized compounds was identified as orthorhombic with some admixture of tetragonal phase. For Sr$\text{}_{1-x}$La$\text{}_{x}$CuO$\text{}_{2+δ}$ the insulator-metal like transition was observed with increasing La content. The d$\text{}_{x²-y²}$ ground state of Cu ions was deduced from electron spin resonance measurements. The electronic state of Cu ions and their surrounding local symmetry was also found to be La and oxygen content dependent

Transport and Magnetic Studies of New Mixed-Valence Compounds: K3\text{}_{3}Cu8\text{}_{8}Se6\text{}_{6}, KCu3\text{}_{3}Se2\text{}_{2}, K3\text{}_{3}Cu8\text{}_{8}Te6\text{}_{6} and BaCuS3−x\text{}_{3-x}

New mixed-valent copper chalcogenides BaCuS$\text{}_{3-x}$ and K$\text{}_{3}$Cu$\text{}_{8}$X$\text{}_{6}$ with X=Se or Te and KCu$\text{}_{3}$Se$\text{}_{2}$, with chemical patterns corresponding to the recently investigated K$\text{}_{3}$Cu$\text{}_{8}$S$\text{}_{6}$ and KCu$\text{}_{3}$S$\text{}_{2}$, were synthesized. For these new samples the results of resistivity and magnetic susceptibility measurements are presented. For BaCuS$\text{}_{3-x}$, K$\text{}_{3}$Cu$\text{}_{8}$Se$\text{}_{6}$ and KCu$\text{}_{3}$Se$\text{}_{2}$ the metal-insulator transition is observed with the low temperature phase being metallic, which is untypical, whereas K$\text{}_{3}$Cu$\text{}_{8}$Te$\text{}_{6}$ is a metal in the investigated temperature range. The temperature dependence of magnetic susceptibility of the studied samples testifies to their diamagnetic or weakly paramagnetic behaviour