Magnetic properties of the low-dimensional spin-1/2 magnet \alpha-Cu_2As_2O_7

In this work we study the interplay between the crystal structure and magnetism of the pyroarsenate \alpha-Cu_2As_2O_7 by means of magnetization, heat capacity, electron spin resonance and nuclear magnetic resonance measurements as well as density functional theory (DFT) calculations and quantum Monte Carlo (QMC) simulations. The data reveal that the magnetic Cu-O chains in the crystal structure represent a realization of a quasi-one dimensional (1D) coupled alternating spin-1/2 Heisenberg chain model with relevant pathways through non-magnetic AsO_4 tetrahedra. Owing to residual 3D interactions antiferromagnetic long range ordering at T_N\simeq10K takes place. Application of external magnetic field B along the magnetically easy axis induces the transition to a spin-flop phase at B_{SF}~1.7T (2K). The experimental data suggest that substantial quantum spin fluctuations take place at low magnetic fields in the ordered state. DFT calculations confirm the quasi-one-dimensional nature of the spin lattice, with the leading coupling J_1 within the structural dimers. QMC fits to the magnetic susceptibility evaluate J_1=164K, the weaker intrachain coupling J'_1/J_1 = 0.55, and the effective interchain coupling J_{ic1}/J_1 = 0.20.Comment: Accepted for publication in Physical Review

Coordination of NK cell markers expression and IgG response in hCMV infection

Human cytomegalovirus (hCMV) is a prevalent virus that affects a large proportion of the population worldwide. Natural Killer (NK) cells are essential immune cells that play a crucial role in controlling hCMV infection. Despite the wide spread of hCMV infection, there is still not enough data related to the association between innate and adaptive immunity. This study investigated the coordination between some of the NK cell markers expression and humoral immune response during hCMV infection. Thirty-three samples obtained from different healthy donors were investigated. The anti-hCMV IgG antibody titer was measured in serum samples, and expression of NKG2C, HLA-DR, CD57, KIR2DL2/DL3, and KIR2DL1 were analyzed in CD56+CD3- cells in PBMC samples by flow cytometry. To evaluate the dependence of proportions of different NK cell subsets on IgG titers, cluster analysis was first performed on all the obtained data, resulting in the identification of four main clusters. The identified clusters demonstrated a dependence on the levels of hCMV antibodies, according to which clusters corresponding to seronegative and low-positive were grouped. The results confirmed that hCMV infection leads to an expansion of NK cell populations expressing the NKG2C marker, which correlates with higher levels of IgG response to hCMV. Besides, we identified increased HLA-DR+ and decreased of KIR2DL1+ NK cells proportions in the middle anti-CMV-IgG level group compared to samples obtained from seronegative and low-positive donors. Moreover, the statistically significant negative correlation was found between KIR2DL1+NK cell percentage and anti-CMV IgG antibody titer, while the positive correlation between HLA-DR+NK cell proportion and the IgG level was noticed only without the cluster corresponded to high level of anti-hCMV IgG. In this cohort, we did not find any association between KIR2DL3 and CD57 expression in NK cells and levels of IgG response to hCMV. This may indicate that different subsets of NK cells may have distinct roles in regulating humoral immunity to hCMV. Overall, the results of the study provide valuable insights into the coordination of NK cell marker expression and IgG response in hCMV infection

LEDs based upon AlGaInP heterostructures with multiple quantum wells: comparison of fast neutrons and gammaquanta irradiation

The paper presents the research results of watt and volt characteristics of LEDs based upon AlGaInP heterostructures with multiple quantum wells in the active region. The research is completed for LEDs (emission wavelengths 624 nm and 590 nm) under irradiation by fast neutron and gamma-quanta in passive powering mode. Watt-voltage characteristics in the average and high electron injection areas are described as a power function of the operating voltage. It has been revealed that the LEDs transition from average electron injection area to high electron injection area occurs by overcoming the transition area. It disappears as it get closer to the limit result of the irradiation LEDs that is low electron injection mode in the entire supply voltage range. It has been established that the gamma radiation facilitates initial defects restructuring only 42% compared to 100% when irradiation is performed by fast neutrons. Ratio between measured on the boundary between low and average electron injection areas current value and the contribution magnitude of the first stage LEDs emissive power reducing is established. It is allows to predict LEDs resistance to irradiation by fast neutrons and gamma rays

Umbilical cord blood as a promising source of NK cells for immunotherapy

Currently, a large number of studies on genetic modification of cord blood NK cells (UCB-NK) are carried out at both clinical and preclinical levels. Immunotherapy based on UCB-NK cells has great potential for antitumor therapy. However, despite having known several advantages over peripheral blood NK cells (PB- NK), including a high concentration in cord blood and low virulence rate, UCB-NK cells are predominantly characterized in the scientific literature as immature and low-functioning NK cells. In this work, we studied the phenotypic characteristics of UCB-NK cells and the possibility of stimulatory compensation of the decreased functional activity of UCB-NK cells. Our studies revealed UCB-NK cells can be characterized as poorly differentiated and weakly activated cells with high level of inhibitory receptor NKG2A and low level of activating receptor NKG2C and HLA-DR, accordingly with the literature data. Two types of stimuli were chosen to stimulate freshly isolated UCB-NK cells: 1) 100 units of IL-2; 2) combinations of 100 units IL-2 and K-562 feeder cells expressing membrane-bound IL-21 (K562-mbIL21). It was shown the degranulation (LAMP-1) and proliferative activity was higher than for parallel cultured ex vivo PB-NK cells under the same conditions for UCB-NK cells stimulated for 7 days with IL-2 + K562-mbIL21. Moreover, stimulation in the way of IL-2 + K562-mbIL21 seemed to be a more perspective way to obtain a large number of proliferatively active UCB-NK cells compared to stimulation with IL-2 only. Since genetic modification of NK cells is a promising way to improve the antitumor properties of NK cells, retroviral transduction procedure was performed to study of the stimulated UCB-NK cells. UCB-NK cells stimulated with IL-2 + K562-mbIL21 were transduced on day 8 of cultivation. In this study, we used targeted overexpression of the adaptor molecule DAP12, which is involved in the signaling of activating NK cell receptors. PB-NK cells and UCB-NK cells were transduced under the equal experimental conditions in same volume of viral particles. As a result, the transduction efficiency was found to be more than 4-fold higher for UCB-NK cells compared to PB-NK cells. Thus, UCB-NK cells appear to be a promising tool for further research in cancer immunotherapy

АНТИАГРЕГАНТНАЯ ТЕРАПИЯ В ПРОФИЛАКТИКЕ НАРУШЕНИЙ МОЗГОВОГО КРОВООБРАЩЕНИЯ

Currently the problem of preventing cerebrovascular disorders, in which antiplatelet therapy takes one of the leading places, remains relevant. The efficiency of the therapy depends on a large number of modifiable and non-modifiable factors. There are many methods to assess the severity of the response to antiplatelet therapy, but there is no common approach to the assessment of the results and their prognostic significance. Further studies of this issue are essential with the aim of individualization of antiplatelet therapy thereby increasing its efficiency and safety.В настоящее время сохраняется проблема профилактики нарушений мозгового кровообращения, в которой антиагрегант­ ная терапия занимает одно из ведущих мест. Эффективность данной терапии зависит от большого числа модифицируемых и не модифицируемых факторов. Существует множество методов оценки ответа на антиагрегантную терапию, но нет единого подхода к оценке получаемых результатов и их прогностической значимости. Необходимы дальнейшие исследования данного вопроса с целью индивидуализации антиагрегантной терапии и, тем самым, повышения ее эффективности и безопасности

Russian consensus statement on the diagnosis and treatment of patients with carotid stenosis

Carotid stenosis is a multidisciplinary problem that requires the involvement of a specialists’ team, including cardiovascular surgeons, neurosurgeons, endovascular surgeons, cardiologists, neurologists, and internists. In this consensus statement, a group of experts considered the main stages of diagnosing carotid stenosis, as well as discussed, the necessary prevention methods and features of choosing the optimal treatment approach. The aim was to provide concise and structured information on the management of patients with carotid stenosis. This document was developed based on the updated clinical guidelines of the European Society for Vascular Surgery and the American Association for Vascular Surgery, taking into account the consensus opinion of Russian experts

Modification of Oligo- and Polylactides With Macrocyclic Fragments: Synthesis and Properties

© Copyright © 2019 Mostovaya, Gorbachuk, Padnya, Vavilova, Evtugyn and Stoikov. Products of lactic acid polycondensation (poly- and oligolactic acids) are widely used as packaging materials, drug delivery agents, implants etc. Variety of their applications is caused by a number of practically important properties, e.g., biocompatibility and biodegradability, non-toxicity, and mechanical durability. Modification of these polymers with different additives allows improving their properties and extending future applications. In this manner, stability toward degradation, recognition of some substrates, extended thermal stability etc. can be improved. Macrocyclic compounds are promising candidates as modifiers. They are able to provide polymer materials with additional binding sites, impart certain orientation to spatial arrangement of polymer chains, change hydrophilic-lipophilic balance, and redox properties. The latter one can be used for assembling various electrochemical sensors and biosensors that combine steric discrimination of the analytes caused by oligolactides and highly sensitive response to their quantities caused by redox labels introduced. Different composite materials based on oligolactides as matrices for such redox labels were described in the assemblies of biosensors for drugs, pesticides, and antioxidants detection. In this mini-review, methods for the synthesis of the lactic acid oligomers and those modified with the macrocyclic fragments (porphyrin, cyclodextrin, and cyclophane) have been described. The effects of modifiers on complexation, thermal, and aggregation properties of materials are described. Analytical performance of oligolactide based sensors and biosensors has been considered with particular emphasis to the mechanism of signal generation

Modification of Oligo- and Polylactides With Macrocyclic Fragments: Synthesis and Properties

© Copyright © 2019 Mostovaya, Gorbachuk, Padnya, Vavilova, Evtugyn and Stoikov. Products of lactic acid polycondensation (poly- and oligolactic acids) are widely used as packaging materials, drug delivery agents, implants etc. Variety of their applications is caused by a number of practically important properties, e.g., biocompatibility and biodegradability, non-toxicity, and mechanical durability. Modification of these polymers with different additives allows improving their properties and extending future applications. In this manner, stability toward degradation, recognition of some substrates, extended thermal stability etc. can be improved. Macrocyclic compounds are promising candidates as modifiers. They are able to provide polymer materials with additional binding sites, impart certain orientation to spatial arrangement of polymer chains, change hydrophilic-lipophilic balance, and redox properties. The latter one can be used for assembling various electrochemical sensors and biosensors that combine steric discrimination of the analytes caused by oligolactides and highly sensitive response to their quantities caused by redox labels introduced. Different composite materials based on oligolactides as matrices for such redox labels were described in the assemblies of biosensors for drugs, pesticides, and antioxidants detection. In this mini-review, methods for the synthesis of the lactic acid oligomers and those modified with the macrocyclic fragments (porphyrin, cyclodextrin, and cyclophane) have been described. The effects of modifiers on complexation, thermal, and aggregation properties of materials are described. Analytical performance of oligolactide based sensors and biosensors has been considered with particular emphasis to the mechanism of signal generation

THE INFLUENCE OF RECIPE COMPONENTS ON QUALITY PARAMETERS OF AERATED DOUGH AND WHOLEGRAIN BREAD FROM CHICKPEA SEEDS

The article presents the results of studying the effect of using table salt, apple juice and citric acid on quality parameters of aerated dough and bread prepared by mechanical leavening. The wholegrain flour from chickpea seeds has been used to prepare dough. The amount of salt is in the range from 1 to 3 %, apple juice from 5 to 25%, citric acid 0.05 to 0.2 % over the weight of the flour. The working mechanism of recipe components on the process of foaming while kneading of the semi-finished products of chickpea flour has been identified. The increase of their amount leads to increase of active acidity of the test and brings the protein pH to isoelectric point. Thus increasing the foaming capacity of the albuminous substances while kneading the semis. It has been founded that the maximum foaming capacity of the semis is achieved at pH 5.5. At the same time a decrease in the bulk density of the dough and the increase in specific volume of the baked product. In this case, the samples are characterized by lower bulk density (0.32 g / cm3 ), and maximum specific volume of finished product (365 cm3 / 100 g). The reasonable amount of components in the bread recipe: table salt 1.5 %, apple juice 5.0 %, citric acid 0.1 % over weight of flour has been recommended. The data obtained form the basis for the development of technology of aerated bread "Atreus" with higher nutritional and biological value. The degree of satisfaction of adult daily need of 100 g of the product is, %: protein 17, dietary fiber 39, magnesium 21, phosphorus 28, iron 30, potassium, thiamine and riboflavin 18. The product is recommended for mass consumption in order to enrich dietary intake with protein, dietary fiber. minerals and vitamins