Charge screening and magnetic anisotropy in metallic rare-earth systems

The calculation of magnetic anisotropy constants is performed beyond the point charge model for a continuous charge density distribution of screening conduction electrons. An important role of the non-uniform electron density, in particular, of the Friedel oscillations, in the formation of crystal field is demonstrated. Such effects can modify strongly the effective ion (impurity) charge and even change its sign. This enables one to justify the anion model, which is often used at discussing experimental data on hydrogen-containing systems. Possible applications to the pure rare-earth metals and RCo5 compounds are discussed. The deformation of magnetic structure near the interstitial positive muon owing to the strong local anisotropy, and the corresponding contribution to the dipole field at the muon are considered.Comment: 10 pages, RevTeX, 3 figure

ОЖИРІННЯ – ПРОБЛЕМА СУЧАСНОСТІ

Тhe article highlights the prevalence of obesity and its main problems associated with human health.У статті висвітлено поширеність розвитку ожиріння та його основні проблеми, пов’язані зі здоров’ям людини

Optical and Tribological Properties of PVD/CVD Diamond-like Carbon Films

The optical and tribological properties of diamond-like carbon (DLC) films deposited by the combination of magnetron sputtering of graphite and plasmochemical dissociation of methane were studied. It was established that at methane concentration in the gas mixture Ar/CH4 at about 5–10 % the formation of DLC films with refraction index n 2.0, microhardness larger than 1000 HK and friction coefficient of 0.06–0.08 becomes possible

mRNA stem-loops can pause the ribosome by hindering A-site tRNA binding [preprint]

Although the elongating ribosome is an efficient helicase, certain mRNA stem-loop structures are known to impede ribosome movement along mRNA and stimulate programmed ribosome frameshifting via mechanisms that are not well understood. Using biochemical and single-molecule Förster resonance energy transfer (smFRET) experiments, we studied how frameshift-inducing stem-loops from E. coli dnaX mRNA and the gag-pol transcript of Human Immunodeficiency Virus (HIV) perturb translation elongation. We find that upon encountering the ribosome, the stem-loops strongly inhibit A-site tRNA binding and ribosome intersubunit rotation that accompanies translation elongation. Electron cryo-microscopy (cryo-EM) reveals that the HIV stem-loop docks into the A site of the ribosome. Our results suggest that mRNA stem-loops can transiently escape ribosome helicase by binding to the A site. Thus, the stem-loops can modulate gene expression by sterically hindering tRNA binding and inhibiting translation elongation

mRNA stem-loops can pause the ribosome by hindering A-site tRNA binding

Although the elongating ribosome is an efficient helicase, certain mRNA stem-loop structures are known to impede ribosome movement along mRNA and stimulate programmed ribosome frameshifting via mechanisms that are not well understood. Using biochemical and single-molecule Forster resonance energy transfer (smFRET) experiments, we studied how frameshift-inducing stem-loops from E. coli dnaX mRNA and the gag-pol transcript of Human Immunodeficiency Virus (HIV) perturb translation elongation. We find that upon encountering the ribosome, the stem-loops strongly inhibit A-site tRNA binding and ribosome intersubunit rotation that accompanies translation elongation. Electron cryo-microscopy (cryo-EM) reveals that the HIV stem-loop docks into the A site of the ribosome. Our results suggest that mRNA stem-loops can transiently escape the ribosome helicase by binding to the A site. Thus, the stem-loops can modulate gene expression by sterically hindering tRNA binding and inhibiting translation elongation

Optical and Tribological Properties of PVD/CVD Diamond-like Carbon Films

The optical and tribological properties of diamond-like carbon (DLC) films deposited by the combination of magnetron sputtering of graphite and plasmochemical dissociation of methane were studied. It was established that at methane concentration in the gas mixture Ar/CH4 at about 5–10 % the formation of DLC films with refraction index n 2.0, microhardness larger than 1000 HK and friction coefficient of 0.06–0.08 becomes possible

M. K. Kadyrbaev’s Archive as a Source for Studying the Stone Monuments of Kazakhstan

The article describes the unpublished archives collected by M. K. Kadyrbaev from his field work in Central Kazakhstan in 1955–1979. It provides information on eight stone statues and structures. The authors attributed and dated them in line with the contemporary rules of archeology. One of the statues appeared to belong to the Saka period of the Tasmola culture. Another monument had no obvious analogies but, possibly, was part of a Qipcaq sanctuary. The authors also touched upon some challenging or debatable issues raised by M. K. Kadyrbaev and other expedition members, e.g., the validity of correlating statues without sings of sex with images of women; the secret Polovtsian sanctuary, which have to be studied in the context of similar Qipcaq sites, etc

Clinical and electroencephalographic characteristics of chronic tic disorders in children and adolescents

Chronic tic disorders (CTDs) are one of the relevant problems of pediatric neurology, the higher prevalence of which is associated with undifferentiated therapy without considering comorbidity.Objective: to enhance the efficiency of diagnosis and therapy of tic disorders in children and adolescents in terms of video-electroencephalography (EEG) monitoring data.Patients and methods. The investigation enrolled 116 patients, including 83 (71.6%) boys and 33 (28.4%) girls at the age of 3 to 15 years (mean age, 9.0±3.0 years), diagnosed with CTD who had been examined at the Specialized Neurology Department, Voronezh Regional Children's Clinical Hospital One, in the period 2010–2014. The investigation consisted of two steps: 1) clinical, laboratory, and neurophysiologic  examination; 2) differentiated therapy. The Yaele Global Tic Severity Scale (YGTSS) was used. The diagnosis was established in accordance with the draft classification of epileptic seizures and epilepsy syndromes by the Intern ational League Against Epilepsy. Video-EEG monitoring was carried out in an awake state and during daytime and/or nighttime sleep. Results and discussion. EEC epileptiform activity was recorded in 46.6% of the patients; a concurrence of CTDs and epilepsy was ascertained in 16.4% of cases. The risk factors of epilepsy in children with CTDs and EEG epileptiform activity are isolated motor tics in the facial region (p=0.0023), MRI epileptogenic changes (p = 0.01), a remitting course (p=0.02), and an early age at the full-scaled picture of tic disorder (p=0.02). CTD therapy with antiepileptic drugs (extended-release valproic acid) was effective and safe in both epileptic seizures (remission in 85.7% of cases) and tics with an improvement in 81.5% of cases with retention in therapy during 2–3 years. Therapy with dopamine transmissionlowering drugs was effective against tics; however, their intake for more than 6 months increased a risk for added epileptic seizures in patients with EEG epileptiform activity (the secondary bilateral synchronization phenomenon and epileptic seizures were recorded in 42.9 and 14.3% of the patients, respectively)