Mechanisms of carrier transport in Cux(SiO2)1-x nanocomposites manufactured by ion-beam sputtering with Ar ions

The present paper investigates the temperature/frequency dependences of admittance Z in the granular Cux(SiO2)1x nanocomposite lms around the percolation threshold xC in the temperature range of 4 30 K and frequencies of 20 MHz. The behavior of low-frequency ReZ(T) dependences displayed the predominance of electrons hopping between the closest Cu-based nanoparticles for the samples below the percolation threshold xC = 0:59 and nearly metallic behaviour beyond the xC. The high-frequency curves ReZ(f) at temperatures T > 10 K for the samples with x < xC exhibited behavior close to ReZ(f) fs with s 1:0 which is very similar to the known Mott law for electron hopping mechanism. For the samples beyond the percolation threshold (x > xC), the frequency dependences of ReZ(f) displayed inductive-like (not capacitive) behaviour with positive values of the phase shift angles

AC hopping conductance in nanocomposite films with ferromagnetic alloy nanoparticles in a PbZrTiO3 matrix

In this work, the temperature and frequency dependences of the real part of the admittance of annealed nanocomposite films containing Co45Fe45Zr10-based nanoparticles covered with native oxides and embedded in a doped PbZrTiO3 ferroelectric matrix were studied. The nanocomposites studied were deposited by ion sputtering a complex target in a mixed Ar/O2 atmosphere followed by a 15-min annealing process (with steps of 25 K) in air in the temperature range of 398 K < Ta < 573 K. The conductivity of the annealed samples was measured in the temperature range of 77 K< Tp < 373 K at frequencies of 50 Hz< f< 1 MHz. The observed r(f, T) dependences confirmed that the annealed samples displayed the effects of negative capacitance over the whole frequency and temperature ranges studied because of the pronounced oxidation of the nanoparticles. The r(f, T) dependences obtained are described using an earlier-developed AC hopping conductance model. Comparisons between experimental and simulation results allow the model parameters to be estimated, such as the activation energies of the hopping conductance and the lifetimes of the electrons in the nanoparticles

Sheet Resistance and Magnetoresistance in Polycrystalline CVD Graphenes

Temperature and magnetic field dependencies of sheet resistance R (T,B) in polycrystalline CVD graphene, investigated in the range of 2≤ T≤ 300 K and magnetic fields 0≤ B≤ 8 T, allowed to determine carrier transport mechanisms in single-layered and twisted CVD graphene. It is shown that for R (T,B) curves for such samples are described by the interference quantum corrections to the Drude conductivity independently on type of precursor and peculiarities of graphene transfer from Cu foil onto the various substrates (glass or SiO2). The twisted CVD graphene samples have demonstrated additional contribution of 2D hopping conductivity into the R (T,B) dependencies. Keywords: graphene, single layer, twisted layers, CVD, carrier transport, magnetoresistance

Anisotropic magnetoresistance of Ni nanorod arrays in porous SiO2/Si templates manufactured by swift heavy ion-induced modification

In this work anisotropic magnetoresistance in nanogranular Ni lms and Ni nanorods on Si(100) wafer substrates was studied in wide ranges of temperature and magnetic feld. To produce Ni films and nanorods we used electrochemical deposition of Ni clusters either directly on the Si substrate or into pores in SiO2 layer on the Si substrate. Pores, randomly distributed in the template have diameters of 100-250 nm and heights about 400-500 nm. Comparison of temperature dependences of resistance and magnetoresistance in Ni films and n-Si/SiO2/Ni structures with Ni nanorods showed that they are strongly dependent on orientation of magnetic field and current vectors relative to each other and the plane of Si substrate. Moreover, magnetoresistance values in n-Si/SiO2/Ni nanostructures can be controlled not only by electric field applied along Si substrate but also by additionally applied transversal bias voltage

Enhanced magnetoresistive effect in the arrays of nickel nanorods on silicon substrates

It is shown that the magnetoresistive properties of n–Si/SiO2/Ni, nanostructures containing nanogranular nickel rods in a SiO2 layer’s vertical pores substantially differ from the similar properties in the earlier studied nanogranular Ni films electrodeposited onto the n–Si plates. From the point of view of the electrophysical properties, the nanostructures studied are analogous to a system of two Schottky Si/Ni diodes, which are connected to each other. The magnetoresistance of such structures has been studied in the temperature range from 2 to 300 K and the magnetic field range of up to 8 Tl. It is established that at temperatures of 17–27 K the structures possess a positive magnetoresistive effect, whose value depends on the transverse voltage applied to the structure and increases with a decrease in the longitudinal (along the rods) current intensity. At a current of 100 nA, the relative magnetoresistance in the field of 8 Tl increases from 500 to 35000% by an increase in the transverse voltage from 0 to –2 V. The observed magnetoresistive effect is associated with the influence of the magnetic field on the processes of impact ionization of impurities resulting in an avalanche breakdown of the Ni/Si Schottky barrier. Thus, the possibility of controlling the magnetoresistive effect in n–Si/SiO2/Ni template structures by applying an additional (transverse) electric field to the nanostructure between the silicon substrate (as the third electrode) and nickel rods is proven

Carrier transport in porous-SiNic-Si nanostructures

In the present paper we have studied the peculiarities of carrier transport properties of nanoheterostructures containing silicon substrate covered with porous silicon layer, where pores were either filled or non-filled with ferromagnetic Ni clusters.We have carried out DC conductivity experiments as a function of temperature (ranging from 2 to 300 K) and porosity of porous silicon layer (between 30% and 70%). Presence of a surface layer with high resistance on the porous silicon top and its role in nanoheterostructure formation was revealed. It was shown that specific electrochemical kinetics of Ni deposition into porous silicon significantly influences resultant nanostructure resistance and high temperature conductance activation energy

The additional professional education of doctors for working in medical institutions profiled in HIV-infection

The article describes the experience of the initial training of doctors in the specialty 'Infectious Diseases' program of additional vocational training to the increase in theoretical and practical sessions on topics of prevention, detection, treatment, clinical supervision, and the multidisciplinary and between departmental interaction for medical and social support for HIV-infected patients and AIDS-related diseases.Представлен опыт первичной подготовки врачей по специальности «инфекционные болезни» по программе дополнительного профессионального образования с увеличением объема теоретических и практических занятий по разделам профилактики, выявления, лечения, диспансерного наблюдения, а также мультидисциплинарного и межведомственного взаимодействия при медико-социальном сопровождении больных с ВИЧ-инфекцией и ВИЧ/СПИД-ассоциированными заболеваниями

Embracing Monogenic Parkinson's Disease: The MJFF Global Genetic PD Cohort

Background: As gene-targeted therapies are increasingly being developed for Parkinson's disease (PD), identifying and characterizing carriers of specific genetic pathogenic variants is imperative. Only a small fraction of the estimated number of subjects with monogenic PD worldwide are currently represented in the literature and availability of clinical data and clinical trial-ready cohorts is limited. Objective: The objectives are to (1) establish an international cohort of affected and unaffected individuals with PD-linked variants; (2) provide harmonized and quality-controlled clinical characterization data for each included individual; and (3) further promote collaboration of researchers in the field of monogenic PD. Methods: We conducted a worldwide, systematic online survey to collect individual-level data on individuals with PD-linked variants in SNCA, LRRK2, VPS35, PRKN, PINK1, DJ-1, as well as selected pathogenic and risk variants in GBA and corresponding demographic, clinical, and genetic data. All registered cases underwent thorough quality checks, and pathogenicity scoring of the variants and genotype–phenotype relationships were analyzed. Results: We collected 3888 variant carriers for our analyses, reported by 92 centers (42 countries) worldwide. Of the included individuals, 3185 had a diagnosis of PD (ie, 1306 LRRK2, 115 SNCA, 23 VPS35, 429 PRKN, 75 PINK1, 13 DJ-1, and 1224 GBA) and 703 were unaffected (ie, 328 LRRK2, 32 SNCA, 3 VPS35, 1 PRKN, 1 PINK1, and 338 GBA). In total, we identified 269 different pathogenic variants; 1322 individuals in our cohort (34%) were indicated as not previously published. Conclusions: Within the MJFF Global Genetic PD Study Group, we (1) established the largest international cohort of affected and unaffected individuals carrying PD-linked variants; (2) provide harmonized and quality-controlled clinical and genetic data for each included individual; (3) promote collaboration in the field of genetic PD with a view toward clinical and genetic stratification of patients for gene-targeted clinical trials. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society

Internist residents’ experience in intensive care units and wards as part of the educational process quality assurance.

Pilot assessment of the internist residents’ experience in intensive care unit of the municipal Hospital 24 is discussed.В статье представлен опыт работы ординаторов-терапевтов в отделении реанимации МБУ ЦГКБ № 24 г. Екатеринбурга