Social and psychological features of inter-cultural adaptation of Russian students in different universities

Modern globalisation processes, the rapid entry of Russia into the world community, have given more opportunities to interact with various ethnic groups ranging from short-term tourist and business contacts to complex processes of migration and emigration. Migrants and visitors have different goals for staying in a new country, meanwhile the researchers note a lot in common within the adaptation processes of both groups. In particular, tension, stresses and experience of cultural shock during adaptation are observed. Therefore, it is necessary to conduct psychological studies not only of migrants who come for a long time to a new country, but also of visitors, i.e., interns, students who come to study in foreign universitie

Possible optical counterpart of PSR J1357-6429

(Abridged) PSR J1357-6429 is a Vela-like radio pulsar that has been recently detected in X-rays and gamma-rays. It powers a compact tail-like X-ray pulsar wind nebula and X-ray-radio plerion associated with an extended TeV source HESS J1356-645. We present our deep optical observations with the Very Large Telescope to search for an optical counterpart of the pulsar and its nebula. We detect a point-like source in V, R, and I bands whose position is within the 1-sigma error circle of the X-ray position of the pulsar, and whose colours are distinct from those of ordinary stars. We consider it as a candidate optical counterpart of the pulsar. If it is indeed the counterpart, its 5-sigma offset from the radio pulsar position, measured about 9 yr earlier, implies that the transverse velocity of the pulsar is in the range of 1600--2000 km s^{-1} at the distance of 2--2.5 kpc, making it the fastest moving pulsar known. The direction of the estimated proper motion coincides with the extension of the pulsar's X-ray tail, suggesting that this is a jet. The tentative optical luminosity and efficiency of the pulsar are similar to those of the Vela pulsar, which also supports the optical identification. However, the candidate undergoes an unusually steep dereddened flux increase towards the infrared with a spectral index of about 5, that is not typical of optical pulsars. It implies a strong double-knee spectral break in the pulsar emission between the optical and X-rays. The reasons for the spectral steepness are unclear. It may be caused by a nebula knot projected onto the jet and strongly overlapping with the pulsar, as observed for the Crab, where the knot has a significantly steeper spectrum than the pulsar. We find no other signs of the pulsar nebula in the optical. Alternatively, the detected source may be a faint AGN, that has not yet been seen at other wavelengths.Comment: 13 pages, 10 figures, 4 table

Immunomodulatory properties of recombinant human granulocyte-macrophage colony-stimulating factor

Granulocyte-macrophage colony stimulating factor (GM-CSF) is a myelopoietic growth factor that exerts pleiotropic effect not only on the differentiation of immature progenitor cells into polymorphonuclear neutrophils, monocytes/macrophages and dendritic cells, but also controls the functioning of differentiated cells. GM-CSF is currently being investigated in clinical trials as an immunomodulator and adjuvant. However, a wide range of biological activities and, sometimes, paradoxical effects of this cytokine require more thorough studies of its action, in order to predict its efficacy under different conditions of immunotherapy. In this work, we have studied the effect of recombinant human GM-CSF on metabolic activity of mouse peritoneal exudate cells in primary cell cultures. Metabolic (redox) activity of the cells was assessed by their ability to reduce nitroblue tetrazolium (NBT) in the course of MF- and Fc-dependent phagocytosis triggered by addition of opsonized zymosan, or sheep erythrocytes to the culture medium. We have shown the dose-dependent stimulatory effect of GM-CSF on the oxidative metabolism of phagocytic peritoneal macrophages and neutrophils. Upon culturing the pepton-elicited cells at wide range of GM-CSF concentrations (5 to 40,000 ng/mL) for 2 and 24 hours, a more pronounced effect of the substance was observed for neutrophils. The GM-CSF preparation caused a significant increase (by 13-17%) in the redox activity of neutrophils induced by opsonized zymosan that persisted at a low dose range, and was retained after 24 hours. The stimulatory effect of GM-CSF on macrophages with NBT index increase by 16% was observed in the short-term cultures. In general, the elicited cells of both types showed a more pronounced response to lower concentrations of GM-CSF (5-125 ng/mL), and weaker effect at higher doses of the preparation. A similar dependence was found when studying the resident macrophages. Culturing of resident cells with GM-CSF at the doses of 5,000 to 40,000 ng/mL for 24 hours caused a significantly increased redox activity of the cells induced by zymosan, or sheep erythrocytes (by 33-52%). In both cases, the maximal response was detected at a dose of 5,000 ng/mL and decreased with increasing dose. The stimulatory effect of GM-CSF upon resident macrophages was more pronounced as compared to elicited cells, which was characterized by the prolonged period of cell activation (up to 24 hours of culture). The data obtained are of interest, in view of prospective usage of GM-CSF as a component of immunomodulatory and adjuvant therapy for various infectious diseases

Stimulating effect of double-stranded yeast RNA on the activity of interferon system genes

Influence of double-stranded RNA (dsRNA) from Saccharomyces cerevisiae yeast upon expression levels of the macrophage genes encoding TLR3 receptor, interferons alpha and beta (IFNα, IFNβ), 2’,5’-oligoadenylate synthetase (OAS) and protein kinase R (PKR) enzymes has been studied in the J774 mouse histiocytic cell culture and in vivo in Balb/c mice. It has been shown that dsRNA exerts a selective activating effect on genes of TLR3 receptor, antiviral proteins IFNα, IFNβ, and OAS, both in vitro and in vivo. With J774 cell culture, the highest induction capacity was observed for the IFNβ gene: 365 to 802-fold. The stimulatory effect was dependent on the dose of dsRNA in the range of 16.9 to 125 μg/ml. The preparation enhanced IFNα gene activity to lesser degree (more than 10-fold), TLR3 and OAS (3 to 4-fold), while the expression levels for these genes were not significantly dependent on the dose of dsRNA. The stimulating effect of dsRNA was dosedependent in murine peritoneal macrophages. The maximum activating effect of the preparation was shown upon administration of the effective antiviral dose (0.5 mg of dsRNA/kg). Five hours after intraperitoneal injection of dsRNA, the highest level of mRNA synthesis was observed for IFNα (54-fold), OAS (43-fold) and TLR3 (28-fold) genes. Expression of the IFNβ gene increased to a lesser degree (9-fold). An increase in the dose of preparation to 1.5 mg/kg led to decrease of the stimulatory effect. Expression levels of the IFNα, TLR3, and OAS genes in that case decreased by 2-4-fold as compared to a lower dose, and the PKR gene expression was 5-fold lower compared to the control. One day after dsRNA administration, a tendency was observed for both experimental groups towards a decreased transcription of macrophage genes, if compared with the 5-hour term. The weakening of gene activity was less pronounced in animals treated with dsRNA at the dose of 1.5 mg/kg. The transcription indices for IFNβ, OAS, and TLR3 genes were much higher during this period (5-10-fold higher than the control values). The dynamics of PKR gene transcription in both experimental systems was significantly different from the expression of other studied genes. The dsRNA preparation at this dose range did not have a pronounced stimulatory effect upon expression of this gene. A moderate increase in PKR gene activity in macrophages of mice was observed only a day following intraperitoneal administration of dsRNA. Concentrations and length of dsRNA molecules are known to be critical factors to the PKR gene activation. An ability to increase the expression of the gene is shown at low dsRNA concentrations (10-7 g/ml and below), while highly polymeric dsRNAs weaken the gene activity. Since the doses and concentrations of dsRNA used in our experiments were significantly different from those mentioned above, it could, in general, affect regulation of PKR gene transcription towards reduction of the stimulatory effect

Study of the adjuvant properties of preparations containing recombinant human granulocyte-macrophage colony stimulating factor

The relevance of the search for new vaccine adjuvants is growing along with the increase in the number of current vaccine preparations, especially those developed on the basis of proteins. Some cytokines are known to exert adjuvant properties. The present work is devoted to the study of adjuvant activity of recombinant human granulocyte-macrophage colony stimulating factor (rhGM-CSF) and constructs based on it. Earlier, we developed a technology for isolation and purification of GM-CSF from the E. coli SG20050/p280_2GM producer strain, as well as a technology for conjugating polyglucin:spermidine complexes with rhGM-CSF. Double-stranded RNA was used to obtain molecular constructs on the basis of rhGM-CSF conjugate. To assemble constructs, the ratio of the components was calculated for one dose of the preparation to contain 5-40 mg of rhGM-CSF and 100 mg of double-stranded RNA. The effectiveness of the formation of molecular constructs was evaluated by dsRNA electrophoretic mobility shift in a 1% agarose gel. The effectiveness of the resulting adjuvants was determined in ELISA assays by measuring the titers of specific antibodies in mouse sera against ovalbumin or recombinant receptor-binding domain of the surface S protein of the severe acute respiratory syndrome coronavirus 2 (Delta variant (B.1.617.2). The experiments were carried out in 100 male BALB/c mice weighing 16-18 g. Mice were immunized twice, with a 14-day interval, by intramuscular injection of 200 mL per animal. Recombinant receptor-binding domain of the surface protein of SARS-CoV-2 was administered at a dose of 50 mg/animal, ovalbumin – at two doses – 1 mg or 5 mg/animal. Corresponding antigen was used as a positive control, a saline solution – as a negative control. It was shown that the maximum effect was achieved by immunization with a construct based on double-stranded RNA and rhGM-CSF conjugated to polyglucin-spermidine. The use of a conjugate without double-stranded RNA as an adjuvant also improved humoral response. The use of native rhGM-CSF did not increase the titers of specific antibodies. Thus, it was found that rhGM-CSF being a part of a polysaccharide conjugate or a molecular construct exerted an ability to enhance the humoral immune response to protein antigens

Development of a vaccine adjuvant based on squalene and study of its adjuvant properties

The use of modern subunit vaccines involves adjuvant introduction into their composition. Currently, the search for new and improvement of existing adjuvant systems is actively underway. Squalene- based adjuvants are well-known and approved in a number of countries for clinical use in influenza vaccines. Our study was devoted to the development of an adjuvant composition on the basis of squalene. The resulting adjuvants were composed in a form of oil emulsion containing a hydrophilic and hydrophobic phase. The stability of the emulsion was achieved by treating it with ultrasound at a frequency of 22 kHz. Particle sizes of the obtained emulsions were examined with the use of an electron microscope. The particle size was calculated to be 50-80 nm for the majority of particles (84%). Adjuvant activity was evaluated in 100 male Balb/C mice, weighing 16-18 g. To assess the humoral immune response, immunization was performed twice, with a 14-day interval, by intramuscular injection of 200 mL per animal. The receptor-binding domain (RBD) of the surface S protein of the severe acute respiratory syndrome coronavirus 2 (Delta variant (B.1.617.2)) or ovalbumin (OVA) from chicken eggs were used as antigens. RBD was administered at a dose of 50 mg/animal; OVA was administered at two doses (1 mg or 5 mg/animal). An antigen with aluminum hydroxide was used as a positive control; a saline solution was used as a negative control. The effectiveness of the obtained adjuvants was determined by measuring the titers of specific antibodies in mouse sera in ELISA assays using the recombinant RBD of SARS-CoV-2 S-protein or ovalbumin from chicken eggs. It was shown that the use of squalene-based adjuvants increased the antigens’ immunogenicity. The average titers of specific antibodies against RBD in the experimental group were 4 times higher than in the group immunized with RBD adjuvanted with aluminum hydroxide. An increase in immunogenicity of the antigen adjuvanted with squalene was also observed in the experimental OVA-group. Thus, it was shown that the developed squalene-based adjuvant compositions could be an alternative to the traditional adjuvants based on aluminum salts

ИНДУКЦИЯ АПОПТОЗА КЛЕТОК МЕЛАНОМЫ В16 ПРИ ВОЗДЕЙСТВИИ ПРЕПАРАТА ФАКТОРА НЕКРОЗА ОПУХОЛЕЙ АЛЬФА В СОСТАВЕ ВИРУСОПОДОБНЫХ ЧАСТИЦ IN VITRO

Aim: to evaluate the antitumor activity of the drug containing TNF-alpha and high-polymer double-stranded RNA (dsRNA) in the composition of virus-like particles (VLP-TNF-alpha) on B16-F10 melanoma cells. Material and Methods. Analysis of the anti-proliferative effect of VLP-TNF-alpha as well as its components, TNFalpha and dsRNA, was carried out using the MTT -test. Apoptosis of melanoma cells was assessed by flow cytofluorimetry with FITC-annexin V. Results. It was shown that the cytotoxic effect of the drug containing the combination of TNF-alpha and dsRNA on melanoma cells significantly exceeded the total cytotoxic effect of TNF-alpha or dsRNA alone (LD50 for combination drug was 0.05 μg/ml, TNF-alpha – 9.5 μg/ml, dsRNA>20 μg/ml). Conclusion. The drug containing TNF-alpha and dsRNA molecules may be a promising drug for the treatment of malignant tumors, including melanoma.Цель исследования – оценка противоопухолевой активности препарата, содержащего фактор некроза опухолей альфа (ФНО-альфа) и двуспиральную рибонуклеиновую кислоту (дсРНК) в составе молекулярной конструкции («вирусоподобной частицы») (ВПЧ-ФНО-альфа), на клетках меланомы B16-F10. Материал и методы. Анализ антипролиферативного действия ВПЧ-ФНО-альфа и его компонентов ФНО-альфа и дсРНК проводили с помощью МТТ-теста, апоптоз клеток меланомы оценивали методом проточной цитофлуориметрии с ФИТЦ-аннексином V. Результаты. Показано, что токсическое воздействие препарата, содержащего ФНО-альфа и дсРНК в составе вирусоподобных частиц, на клетки меланомы значительно превышает суммарный токсический эффект ФНО-альфа и дсРНК в отдельности (ЛД50 составляет, соответственно, для комплексного препарата 0,05 мкг/мл, ФНО-альфа – 9,5 мкг/мл, дсРНК >20 мкг/мл). Заключение. Препарат, содержащий ФНО-альфа и дсРНК в молекулярной конструкции, может быть многообещающим терапевтическим средством для лечения злокачественных новообразований, включая меланому

Orbital-selective band hybridisation at the charge density wave transition in monolayer TiTe2

Funding: We gratefully acknowledge support from the Leverhulme Trust and the Royal Society. W.R. is grateful to University College London for awarding a Graduate Research Scholarship and an Overseas Research Scholarship. O.J.C. and K.U. acknowledge PhD studentship support from the UK Engineering and Physical Sciences Research Council (EPSRC, Grant Nos. EP/K503162/1 and EP/L015110/1). I.M. and E.A.-M. acknowledge studentship support from the International Max-Planck Research School for Chemistry and Physics of Quantum Materials. S.R.K. acknowledges the EPSRC Centre for Doctoral Training in the Advanced Characterisation of Materials (CDT-ACM, EP/S023259/1) for funding a PhD studentship.Reducing the thickness of a material to its two dimensional (2D) limit can have dramatic consequences for its collective electronic states, including magnetism, superconductivity, and charge and spin ordering. An extreme case is TiTe2, where a charge density wave (CDW) emerges in the single-layer which is absent for the bulk compound, and whose origin is still poorly understood. Here, we investigate the electronic band structure evolution across this CDW transition using temperature-dependent angle-resolved photoemission spectroscopy. Our study reveals an orbital-selective band hybridisation between the backfolded conduction and valence bands occurring at the CDW phase transition, which in turn leads to a significant electronic energy gain, underpinning the CDW transition. For the bulk compound, we show how this energy gain is almost completely suppressed due to the three-dimensionality of the electronic band structure, including via a kz-dependent band inversion which switches the orbital character of the valence states. Our study thus sheds new light on how control of the electronic dimensionality can be used to trigger the emergence of new collective states in 2D materials.Publisher PDFPeer reviewe