Wavelength-stabilized near-field laser.

Surface-trapped electromagnetic waves can be localized at a boundary between a semiconductor distributed Bragg reflector (DBR) and a homogeneous dielectric medium or air. These waves enable a novel class of in-plane-emitting optical devices including edge-emitting lasers, disk microlasers or near-field fiber-coupled lasers. We show that the surface-trapped modes can be controlled by tuning the thickness of a single DBR layer. Diagrams in variables "wavelength - thickness of the control layer" are constructed for both TM and TE optical modes revealing the parameter domains, in which surface-trapped modes exist. The domains contain cusps, in the vicinity of which a surface-trapped optical mode is allowed only in a narrow spectral region, enabling wavelength-stabilized operation of a laser. For a structure designed for lasing at ∼1 µm, the lasing wavelength shifts upon temperature increase at a rate ∼0.08 nm/K. The fraction of the optical power of the surface-trapped mode accumulated in the homogeneous dielectric can reach ∼50%. Thus, such structure is a near-field wavelength-stabilized semiconductor laser. Further, such structure can be applied as a wavelength-stabilized semiconductor optical amplifier adjacent to a dielectric waveguide or an optical fiber, both for integrated photonics and for ultrahigh-brightness laser diodes and diode arrays and stacks.

Virtual cavity in distributed Bragg reflectors.

We show theoretically and experimentally that distributed Bragg reflector (DBR) supports a surface electromagnetic wave exhibiting evanescent decay in the air and oscillatory decay in the DBR. The wave exists in TM polarization only. The field extension in the air may reach several wavelengths of light. Once gain medium is introduced into the DBR a novel class of diode lasers, semiconductor optical amplifiers, light-emitting diodes, etc. can be developed allowing a new type of in-plane or near-field light outcoupling. To improve the wavelength stability of the laser diode, a resonant cavity structure can be coupled to the DBR, allowing a coupled state of the cavity mode and the near-field mode. A GaAlAs-based epitaxial structure of a vertical-cavity surface-emitting laser (VCSEL) having an antiwaveguiding cavity and multiple GaInAs quantum wells as an active region was grown and processed as an in-plane Fabry-Pérot resonator with cleaved facets. Windows in the top stripe contact were made to facilitate monitoring of the optical modes. Three types of the optical modes were observed in electroluminescence (EL) studies under high current densities > 1 kA/cm2. Mode A with the longest wavelength is a VCSEL-like mode emitting normal to the surface. Mode B has a shorter wavelength, emitting light at two symmetric lobes tilted with respect to the normal to the surface in the direction parallel to the stripe. Mode C has the shortest wavelength and shifts with a temperature at a rate 0.06 nm/K. Polarization studies reveal predominantly TE emission for modes A and B and purely TM for mode C in agreement with the theory. Spectral position, thermal shift and polarization of mode C confirm it to be a coupled state of the cavity mode and near-field DBR surface-trapped mode.

Evaluation of Individual Risk Factors of Alcohol Preference in Rats.

We evaluated individual risk factors of the development of alcohol preference in a model of voluntary alcohol consumption. Drinking behavior was estimated in the two-bottle test, and other behavioral features were studied in the open field test, test for social interaction, and marble burying test. The low adaptive capacity of an animal, which was manifested in a shorter time spent in the center of the open field, and low consumption of ethanol when the animal first tasted it were the leading factors of the subsequent preference of alcohol under the conditions of free choice.

Sucrose-enriched diet during maturation increases ethanol preference in rats.

In the present study we used a diet enriched with 10% sucrose, which was consumed by adolescent animals of the experimental group for one month. We found that consumption of sweet food during sexual maturation affected alcohol preference, anxiety, and locomotor and exploratory activity in the adult rats. Our data show that easily available tasty food during adolescence probably impairs the reward system and serves as a trigger of future alcohol preference.

[Oncolytic potential of recombinant influenza A virus vectors on a model of malignant glioma in vivo].

Malignant glioma is the most frequently occurring primary brain tumor. Despite significant progress in the diagnostics and treatment of neoplastic diseases the prognosis for patients with III-IV grade gliomas, remains extremely unfavorable. Rapidly developing area in oncology is the employment of therapeutic viruses with natural or genetically engineered oncolytic activity. In the present study we demonstrated the oncolytic potential of a recombinant influenza A virus vector with impaired interferon antagonism function of NS1 protein in treatment of malignant glioma. Recombinant influenza A virus (HA-DS-GFP) expressing green fluorescent protein from the NS1 open reading frame was used as a model vector. HA-DS-GFP virus has shown infectivity towards glioma cells both in vitro, and in vivo (experimental glioma model in rats). Intratumoral inoculation of HA-DS-GFP resulted in a substantial inhibition or complete regression of tumor growth. Our data demonstrate that recombinant influenza vectors have promising potential in therapy of malignant gliomas.

[Ebola hemorrhagic fever: Properties of the pathogen and development of vaccines and chemotherapeutic agents].

Ebola hemorrhagic fever (EHF) epidemic currently ongoing in West Africa is not the first among numerous epidemics in the continent. Yet it seems to be the worst EHF epidemic outbreak caused by Ebola virus Zaire since 1976 as regards its extremely large scale and rapid spread in the population. Experiments to study the agent have continued for more than 20 years. The EHF virus has a relatively simple genome with seven genes and additional reading frame resulting from RNA editing. While being of a relatively low genetic capacity, the virus can be ranked as a standard for pathogenicity with the ability to evade the host immune response in uttermost perfection. The EHF virus has similarities with retroviruses, but belongs to (-)RNA viruses of a nonretroviral origin. Genetic elements of the virus, NIRV, were detected in animal and human genomes. EHF virus glycoprotein (GP) is a class I fusion protein and shows more similarities than distinctions in tertiary structure with SIV and HIV gp41 proteins and even influenza virus hemagglutinin. EHF is an unusual infectious disease, and studying the molecular basis of its pathogenesis may contribute to new findings in therapy of severe conditions leading to a fatal outcome.

[Genetic stability of the HA, NA, and NS genes of the recombinant vector virus Flu-NS1-124-Omp16 (H5N1) expressing the brucellar gene].

The recombinant strain Flu-NS1-124-Omp16 (H5N1) of the influenza virus expressing the brucellar Omp16 gene was constructed on the basis of the technology of reverse genetics for the purpose of developing vector anti-brucellosis vaccine. The obtained recombinant strain is a genetically stable construction. This stability is confirmed by the comparative analysis of the nucleotide sequences of the HA, NA, and NS genes of the recombinant vector virus Flu-NS1-124-Omp16 (H5N1) expressing the Omp16 gene of the Brucella abortus (GenBank: AAA59360.1). The comparative analysis showed that the nucleotide sequence of the NS gene of the first and the fifth passage level of the Flu-NS1-124-Omp16 (H5N1) virus corresponded for 100% to the initial part of 12AAS2TC_124 Omp16g containing the chimera NS1-124-Omp16 in the composition of DNA (deoxyribonucleic acid) plasmids pHW2000. Total identity with HA and NA genes of the strain A/AstanaRG/6:2/2009 (H5N1) was shown by the comparative analysis of the nucleotide sequences of HA and NA genes of the first and the fifth passage level of the recombinant strain Flu-NS1-124-Omp16 (H5N1). The recombinant vector virus Flu-NS1-124-Omp16 (H5N1) expressing the brucella Omp16 gene maintains the genetic stability during 5 passages in 10-day developing chicken embryos.

Contact properties to CVD-graphene on GaAs substrates for optoelectronic applications.

The optimization of contacts between graphene and metals is important for many optoelectronic applications. In this work, we evaluate the contact resistance and sheet resistance of monolayer and few-layered graphene with different metallizations using the transfer length method (TLM). Graphene was obtained by the chemical vapor deposition technique (CVD-graphene) and transferred onto GaAs and Si/SiO2 substrates. To account for the quality of large-area contacts used in a number of practical applications, a millimeter-wide TLM pattern was used for transport measurements. Different metals--namely, Ag, Pt, Cr, Au, Ni, and Ti--have been tested. The minimal contact resistance Rc obtained in this work is 11.3 kΩ µm for monolayer CVD-graphene, and 6.3 kΩ µm for a few-layered graphene. Annealing allows us to decrease the contact resistance Rc and achieve 1.7 kΩm µm for few-layered graphene on GaAs substrate with Au contacts. The minimal sheet resistance Rsh of few-layered graphene transferred to GaAs and Si/SiO2 substrates are 0.28 kΩ/□ and 0.27 kΩ/□. The Rsh value of monolayer graphene on the GaAs substrate is 8 times higher (2.3 kΩ/□), but it reduces for the monolayer graphene on Si/SiO2 (1.4 kΩ/□). For distances between the contacts below 5 µm, a considerable reduction in the resistance per unit length was observed, which is explained by the changes in doping level caused by graphene suspension at small distances between contact pads.

[Pharmacological action on emotional sphere with phenazepam and caffeine changes preference of ethanol in Wistar male rats].

Earlier we have shown that essential for formation of preference to alcohol is not that much the initial anxiety level, but rather direction of its change in the process of forced alcoholization. The goal of this work was study of effect of change in the anxiety level on formation of action on the emotional sphere. Out of four groups, for 4 months of experiment, the 1st group had access only to the 10 % ethanol solution; the 2nd group--to the 10% ethanol with addition of 0.4 g/l caffeine; the 3rd - to 10% ethanol with 0.5 mg/l phenazepam; the 4th (control)--only to water. The anxiety level and behavioral parameters were estimated prior to the experiment and after each 5 weeks with aid of the test "the open field". Preference of ethanol was determined with aid of the test "the two-glass sample" before the experiment and each 4 weeks. In experimental groups of rats the long-term consumption of ethanol, of ethanol with caffeine, and of ethanol with phenazepam led to an increase in preference of alcohol as compared with control. A decrease of motor activity at the period of forced alcoholization was found to correlate positively with the low level of preference of alcohol. The rats consuming ethanol with caffeine and sensitive to action of the psychostimulator enhancing anxiety formed faster the preference to alcohol. In rats not sensitive to action of caffeine the preference to alcohol was not formed. Rats sensitive to the sedative action of phenazepam were less anxious and subsequently did not prefer alcohol. In rats not sensitive to phenazepam, anxiety was enhanced and preference to alcohol was formed.

Rapid Assessment of Neutralizing Antibodies Using Influenza Viruses with a Luciferase Reporter.

Influenza viruses cause acute respiratory infections, especially in the autumn-winter period. They are characterized by a high mutation frequency and cause annual seasonal epidemics. The detection of antibodies that neutralize the virus is an important criterion in the assessment of population immunity and the influenza vaccine effectiveness. In this study, a method for determining the titer of virus-neutralizing antibodies in blood serum has been developed. A new test called the luciferase neutralization assay uses a bioluminescent signal for detection. The assay is based on engineered influenza reporter viruses with various surface antigens and a nanoluciferase reporter protein in the NS1 reading frame. Using the developed method, we studied paired sera of volunteers obtained before and after vaccination. The proposed assay was compared with the conventional antibody assessment methods (microneutralization and hemagglutination inhibition assay); a high degree of correlation was observed. At the same time, the use of the luciferase neutralization assay made it possible to reduce the time required for the analysis and to simplify the detection procedure. Supplementary Information: The online version contains supplementary material available at 10.1134/S0003683822070067.

[An associations of possible genetic risk markers for Internet addiction with childhood trauma experience and personality traits in young adults : preliminary results]. / Svyaz' geneticheskikh markerov riska razvitiya internet-zavisimosti s detskim psikhotravmiruyushchim opytom i lichnostnymi osobennostyami u molodykh vzroslykh: predvaritel'nye rezul'taty.

OBJECTIVE: To study was to test an associations of the preliminary genetic risk markers for Internet addiction (IA) with clinical, psychological and personality characteristics, taking into account the childhood traumatic experience, in 44 IA persons compared with 120 healthy individuals. MATERIAL AND METHODS: The study included 164 participants: 44 individuals with IZ (group IZ), male and female, aged 16 to 30 years in the absence of diagnoses of mental health problems. diseases from rubrics F00-09 and F20-29 (ICD-10) and 120 healthy (control group). RESULTS AND CONCLUSION: We have found an associations of the preliminary IA genetic risk markers with some personality traits and behavioral characteristics (TCI-125, TIPI) and with the childhood trauma experience (ACE IQ, CTQ), both for healthy individuals and to a greater extent for IA individuals, that may suggests the possible effects of the gene-environment interaction on a risk of developing IA. The data obtained on the structure of associations between IA genetic risk markers and individual psychological characteristics under the significant influence of the childhood trauma experience allow us to proceed with the construction of models for IA risk prediction taking into account the "gene - environment" interactions.

[Vaccination with virus-like particles containing hemagglutinin protects the lungs of mice with postifluenza bacterial pneumonia: virological, microbiological and clinical data].

INTRODUCTION: Influenza is a severe viral disease, a frequent complication of which is a secondary bacterial pneumonia. Influenza vaccines prevent secondary bacterial complications. Virus-like particles are one of the promising areas for the development of new vaccines. The aim of this work is to study the correlation of the pathomorphological characteristics of the lungs with clinical, virological, and microbiological markers of the disease at vaccination with virus-like particles (VLPs), containing hemagglutinin (HA) of influenza virus (HA-Gag-VLPs) in a murine model of secondary bacterial pneumonia induced by S. pneumoniae after influenza infection. MATERIAL AND METHODS: BALB/c mice were vaccinated with VLPs containing influenza HA. After 21 days, mice were infected with two strains of influenza viruses, homologous and non-homologous, and 5 days after viral infection, were infected with S. pneumoniae. The vaccination effect was evaluated by morphological, virological (titer of the virus in the lungs) and microbiological (titer of bacteria in the lungs) data, and was confirmed by clinical data (survival, change in body weight). RESULTS: Immunization with HA-Gag-VLPs, followed by infection with a homologous influenza virus and S. pneumoniae, reduced the area of foci of inflammation, inhibited the replication of the virus and bacteria in the lungs, and also protected animals from death and reduced their weight loss. Immunization with HA-Gag-VLPs upon infection with a heterologous strain and S. pneumoniae did not affect these criteria. CONCLUSION: The immunization with HA-Gag-VLPs prevented the viral replication, providing a reduction of S. pneumoniae titer and the degree of lung damage, protecting animals from the disease in a murine model of secondary bacterial pneumonia, induced by S. pneumoniae, after influenza infection with homologous strain of the virus.

[Clinical and psychological features of people with internet dependence: experience of a pilot study]. / Kliniko-psikhopatologicheskie osobennosti lits s internet-zavisimost'yu: opyt pilotnogo issledovaniya.

OBJECTIVE: The prevalence of Internet addiction (IA) is growing steadily, especially among the younger generation. The purpose of this multicenter study was to investigate the socio-demographic characteristics, clinical varieties, and profile of psychopathological symptoms of mental disorders in patients with IA. MATERIAL AND METHODS: The study included 2 groups: the main group consisted of 44 people, aged 16 to 34 years, average age 22.00±0.66 years, 33 (75%) men, 11 (25%) women; the control group included 120 people, aged 19 to 30 years, average age 23.13±0.18 years, 90 (74.3%) men, 30 (26.7%) women. Groups were identified at the testing stage based on the total score on the Chen Internet Addiction Scale (CIAS). The main group included individuals who scored CIAS 65 points or higher. The specially developed Unified Study Card, The Mini international neuropsychiatric interview (MINI), the Hospital Anxiety and Depression Scale (HADS), the Beck Depression Questionnaire (BDI), the Prodromal Questionnaire-16 (PQ-16), the Symptom Checklist-90-Questionnaire Revised (SCL-90-R). RESULTS AND CONCLUSION: There were more people with secondary specialized education and unemployed in the main group. The family burden of addiction and psychiatric disorders did not differ in both groups, and the heredity of somatic diseases was lower in the IA group. In the IA group, a psychiatric diagnosis was made 9 times more often. The severity of affective and anxiety disorders was higher in the IA group, while the risk of psychosis was low that allows considering the symptoms of IA outside the framework of subpsychotic mental disorders. The features of the psychopathological symptoms of IA were: total «tension¼ of the psychopathological profile; a relatively uniform and slightly specific profile of psychopathological symptoms with a certain tendency to the prevalence of personality-related stress manifestations.

[Current approaches to the treatment and correction of Internet addiction]. / Sovremennye podkhody k terapii i korrektsii internet-addiktsii.

According to WHO consensus decision, gambling disorder, including the form of Internet addiction (IA), should be included in the section 'Impulsive disorders and behavioral addictions' of ICD-11. Population studies in the USA and Europe show the prevalence of IA from 1.5 to 8.2%, and in the countries of Southeast Asia it reaches 20-30% among young people. All this raises questions about the development of standardized approaches to the treatment and correction of this disorder. The review covers pharmacological and non-pharmacological approaches. Several studies and clinical observations have been devoted to pharmacological methods for treating IA, including the successful use of antidepressants such as escitalopram, clomipramine, and bupropion. There are data on the effectiveness of quetiapine, clonazepam, naltrexone and methylphenidate. In general, research was limited to methodological deficiencies, including small sample sizes, lack of control groups etc. Of non-pharmacological and psychotherapeutic approaches, in particular, cognitive-behavioral therapy (CBT) is the most studied. Special programs CBT are developed focused on children and teenagers. In addition to CBT, other psychotherapeutic approaches were used for the correction of IA: reality therapy, Internet interventions, acceptance and responsibility therapy, family therapy, complex methods. In many countries educational medical camps have been established (for example, sports or other outdoor activities) for adolescents with IA. Further studies in the field are needed to develop treatment approaches and diagnostic classification of IA.

[The treatment of non-chemical addictions]. / Terapiia nekhimicheskoi zavisimosti.

Today, there are no standards of therapy for non-chemical (behavioral) addictions. The article examines in detail modern psychological (classes in the 12 step program groups, various psychotherapeutic interventions) and pharmacological (antidepressants, opioid receptor antagonists, normotimics, glutamatergic agents, etc.) approaches to the treatment of pathological gambling. The possibilities of therapy of love and sexual addiction are analyzed. Separately, the problems of correction of the so-called socially acceptable addictions, as well as Internet addictions, are considered. The extremely cautious tactics in the therapy of these forms is recommended, because they can transform into heavy chemical and behavioral addictions. The importance of using a number of socially acceptable addictions as substitutes for the treatment of severe forms of dependences is underlined. In conclusion, the questions of the competency of a psychiatrist-addiction specialist and a psychologist in the correction of behavioral dependencies are analyzed and indications for psychopharmacotherapy are determined.

[Psychosocial characteristics of alcohol dependence patients committed self-poisoning suicide attempt]. / Psikhosotsial'naia kharakteristika lits, sovershivshikh suitsidal'nye popytki otravleniia.

AIM: To determine с psychosocial characteristics of alcohol-dependent patients committed self-poisoning suicide attempt. MATERIAL AND METHODS: Individuals, who were admitted to the toxicology department after the self-poisoning suicidal attempt, were studied. The socio-demographic, personal history data together with experimental psychological methods (V.P. Dvorschenko Personality Accentuation Test, AUDIT, Beck Hopelessness and Suicide Intention Scales, Barratt Impulsivity Scale) were used. RESULTS AND CONCLUSION: Individuals, who attempted suicide and abused alcohol, were characterized by the higher level of impulsivity, tendency to drug addiction, reduced ability to self-control and activity planning. They had excitable accentuation types and committed demonstrative suicidal attempts more often. Alcohol abuse was positively correlated with a tendency to drug addiction, impulsivity and was negatively correlated with the true suicide attempt and tendency to depression. Psychological characteristics of individuals with alcohol dependence committed suicide attempt differ from individuals without alcohol abuse.

[Early social isolation increases alcohol preference in experiment].

OBJECTIVE: To study the formation of alcohol preference in rats subjected to early social isolation, a possible model of schizophrenia. MATERIAL AND METHODS: The study was carried out on 45 Wistar male rats, aged 21--24 days. The experimental animals were dropped from the parental cells in the individual cells for 35 days, control rats were kept in standard conditions (5 animals per cage). Allanimals were subjected to forced alcohol drinking for three and ahalf months according to the following scheme: access to the15% ethanol solution (Monday, Wednesday, Friday), drinking deprivation (Tuesday, Thursday), free access to the water (Saturday, Sunday). Alcohol preference was evaluated in the «two-bottle¼ test, behavior characteristics -- in the «open field¼ and the «behavioral despair¼ tests. RESULTS AND CONCLUSION: Rats subjected to isolation significantly more of ten preferred alcohol in the «two-bottle¼ test after 0.5, 2 and 3 months of forced alcohol drinking. After the end of isolation and before forced alcohol drin-king, the experimental rats showed greater locomotor activity in the «open field¼ test. According to the exploratory activity and emotionality, the rats in both groups had no significant differences. The rats subjected to isolation, were significantly more sensitive to the sound stimulus and lingered ongerin the start area in the «open field¼. Thus, the combination of early social isolation and forced alcohol drinking leads to greater alcohol preference in experimental animals. Significant differences in alcohol preference were observed after the start of forced alcohol drinking while immediately after isolation the rats of both groups had no differences in their relation to alcohol. After 3.5 months of forced alcohol drinking, the isolated rats demonstrated decreased behavioral despair in the same test.

[The use of agomelatine (valdoxan) in gambling therapy: a pilot study].

OBJECTIVE: To study the antidepressant agomelatine (M1/M2 agonist and 5-HT2C antagonist) in pathological gambling (PG) (ICD-10 item F63.0). MATERIAL AND METHODS: An open label 8-week trial was carried out in 22 outpatients (17 male and 5 female, mean age 38±7). PG severity was assessed by the Yale-Brown Obsessive-Compulsive Scale adapted for Pathological Gambling (PG-YBOCS). Anxiety and depression level was measured by the Hospital Anxiety Depression Scale (HADS). RESULTS: Agomelatine significantly decreased PG-YBOCS scores from the second week of the trial (12.6±3.0 compared to 24.2±2.1 at baseline, p<0.05). In the end of the trial, PG-YBOCS score decreased to 5.3. The total HADS score decreased significantly in the end of the study (from 23.6±2.9 to 11.4±1.9, p<0.05). There was an improvement in behavior as well. CONCLUSION: Thus, agomelatine has demonstrated efficacy in PG patients.

Diffusive Propagation of Exciton-Polaritons through Thin Crystal Slabs.

If light beam propagates through matter containing point impurity centers, the amount of energy absorbed by the media is expected to be either independent of the impurity concentration N or proportional to N, corresponding to the intrinsic absorption or impurity absorption, respectively. Comparative studies of the resonant transmission of light in the vicinity of exciton resonances measured for 15 few-micron GaAs crystal slabs with different values of N, reveal a surprising tendency. While N spans almost five decimal orders of magnitude, the normalized spectrally-integrated absorption of light scales with the impurity concentration as N(1/6). We show analytically that this dependence is a signature of the diffusive mechanism of propagation of exciton-polaritons in a semiconductor.

Super-radiant mode in InAs-monolayer-based Bragg structures.

We report direct experimental evidence of the collective super-radiant mode in Bragg structure containing 60 InAs monolayer-based quantum wells (QWs) periodically arranged in GaAs matrix. Time-resolved photoluminescence measurements reveal an appearance of the additional super-radiant mode, originated from coherent collective interaction of QWs. This mode demonstrates a super-linear dependence of the intensity and radiative decay rate on the excitation power. The super-radiant mode is not manifested in the case if only a small number of QWs is excited.