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We report a technique for studying the absorption of optical radiation in layers of a semiconductor heterostructure by the method of probe radiation coupling. The studies are carried out using specially made isotype samples based on AlGaAs/GaAs, simulating an n-type doped laser waveguide with a concentration of 1017 – 1018cm−3. The main features of the experimental setup and calculation methods are described. A high (up to 95%) efficiency of light coupling into the waveguide and an error in measuring the absorption coefficient at a level of 0.1 cm−1 are achieved. The possibilities of studying the polarisation and temperature dependences of radiation absorption by free carriers are experimentally demonstrated. It is shown that with an increase in temperature in the range 25 – 85°C, the absorption in the samples increases by 15%.

Perceptions of hepatitis E have transformed over the past decade. This infection was common only in some developing countries. It is known now that hepatitis E occurs in most high - income countries and is largely a zoonotic infection. The review analyzes the relevant key publications and recommendations on the diagnosis and treatment of hepatitis E. Theproblems of diagnosis, treatment and prevention of hepatitis E caused by genotypes 3 and 4 are highlighted. It is shown that with symptoms of acute hepatitis for hepatitis E virus infection (HEV) it is advisable to test not only travelers returning from areas endemic for 1 or 2 genotypes (Asia, Africa, Mexico) and pregnant women, but also all patients, after excluding other reasons for changing liver tests. Testing for HEV is also recommended for patients with chronic liver disease with unexplained deterioration, for patients with immunosuppression and changes of liver tests, for patients with systemic manifestations of diseases of the nervous system. A combination of serological testing and nucleic acid amplification methods are recommended for the diagnosis of HEV infection. Treatment of HEV infection includes the use of antiviral therapy in severe cases; if possible, for patients who underwent transplantation of solid organs - a reduction in doses of immunosuppressive drugs for pregnant women - intensive therapy. Prevention of HEV infection is aimed at people with chronic liver diseases and receiving immunosuppressive therapy who should be excluded from the use of mollusks and poorly fried pig, boar and deer meat.

A laser source for bleaching passive Q-switches of erbium-ytterbium lasers is developed and studied. The developed and studied compact pulsed module (peak power exceeding 10 W in a pulse with a duration of 1 μs at a wavelength around 1550 nm) is made on the basis of a semiconductor lasers with an ultra-narrow waveguide integrated with a pulsed pump card. To optimise the output laser characteristics, a series resistance was used in the laser pump circuit. The powers of the free-space and fibre-coupled modules at a temperature of 25 °C are 15 and 12 W, respectively, at a pulse shape close to rectangular.

We investigated the effect of AlInAs energy barrier layers on the edge-emitting lasers of 1400–1600 nm spectral range. It was shown that the barrier layer at the waveguide-cladding heterojunction provides charge carrier accumulation in the waveguide and prevents the internal quantum efficiency from drop. The use of barrier layer enables increasing the pulse optical power from 9 to 13 W from 100 μm aperture.

Aim of the study. To estimate efficacy and safety of 3D mode of interferon­free therapy in patients with subcompensated liver cirrhosis (LC) of HCV etiology (genotype 1b). Material and methods. Original study included the data of 66 patients (26 men and 40 women) with subcompensated LC of HCV etiology (genotype 1b) who underwent interferon­free therapy by ombitasvir/paritaprevir/ritonavir, dasabuvir and ribavirin for 12 weeks (the latter was cancelled at receiving the new data on treatment efficacy after 4 weeks of therapy) in September, 2015, before the drug instruction was updated. Mean age of patients was 56.4±10.0 years. At onset of etiological therapy 21 patients (31.8%) had Child­Pugh score of 9, eleven patients (16.7%) had Child­Pugh 8, 34 patients (51.5%) had Child­Pugh 7. The causes of inefficacy of previous modes of combined antiviral therapy (CAT) included absence of virologic response in 43.9% of the cases, recurrence of HCV replication - in 30.3%, virological breakthrough - in 16.7%, development of serious adverse effects - in 9.1%. Taking into account the change of the group quantity during the course of therapy because of treatment cancellation for safety reasons and the subsequent assessment of its efficacy in patients with early treatment cancellation, the modified «intent­to­treat» (ITT) analysis was the basic method of results evaluation. Along with that «per protocol» (PP) analysis was carried out as well. Results. During the treatment course aviremia in 14 days was achieved in 53.8% of patients (in 35 patients of 65), prompt virologic response - at 79.7% (in 51 of 64 patients). All patients underwent complete 12 week course of CAT (n=60) and those for whom treatment was canceled for safety reasons (n=3) - in terms from 14 to 30 days - sustained virologic response (SVR) in 12 weeks and SVR in 24 weeks was registered. The assessment of liver function compensation degree in 6 months after CAT termination demonstrated 3 to 4 points reduction of the Child-Pugh Score in 21 patients (33.9 %), 1 to 2 points in 35 patients (56.5 %). According to the MELD score the clinical improvement was achieved in 66.1% of patients. The early treatment termination was caused by progression of hepatic encephalopathy symptoms and/or jaundice development (4 cases). Most cases of the progression­related treatment termination due to liver failure were reversible after CAT interruption. Three lethal outcomes after the early treatment termination and 1 patients death in follow­up period were registered. Conclusion. Antiviral therapy in 3D mode for subcompensated LC is highly effective not only in those patients who received complete treatment course, but also in those with early treatment secession. Profiling of 3D therapy safety demonstrated that development of serious adverse effects during the treatment is comparable to outcomes at natural course of subcompensated LC in the absence of etiological therapy.

The majority of deaths related to complications of liver cirrhosis would have been preventable with timely diagnosis and proper treatment. However, absence of the population-based screening programs for hepatitis, an asymptomatic course of the majority of liver disorders, failures in the registration of etiologically confirmed cases of liver cirrhosis, low population awareness of its risks and of current diagnostic and management opportunities do impede the collection of reliable epidemiological data on the incidence and prevalence of liver disorders including their end-stages, and on the related mortality of the population; as a consequence, all these factors hinder a comprehensive assessment of the medical and social burden of hepatic disorders. Medical registries are the single system for their registration and follow-up. Analysis of data from the Moscow Regional Registry of patients with liver disease has shown that the leading cause of liver cirrhosis is HCV infection (66%), with alcoholic liver cirrhosis ranking second (16.1%). There is a trend towards higher proportions of liver cirrhosis as an outcome of HCV hepatitis among newly referred patients (7.2% in 2012 and 10.6% in 2016). HCV genotype characteristics determine the rates of the disease progression: in those with genotype 3, liver cirrhosis would occur at an earlier age (51.8% of patients aged from 26 to 45) than with genotype 1 (58.7% of patients aged from 46 to 65). In older patients, various comorbidities can contribute to the development of liver cirrhosis. Among patients with HBV infection, 4.9% have liver cirrhosis, and most of patients receive antiviral treatment with nucleoside/nucleotide analogues. The highest percentage of liver cirrhosis has been found in the patients with chronic D hepatitis (46/116, 39.7%). In 10.3% of the patients with chronic D hepatitis, the aggressive course of the disease leads to primary liver cancer. Thus, the necessity of the development of prevention measures and early detection of liver disorders, as well as modernization of the public healthcare system at all stages of medical care should be recognized as the short-term goals, in addition to the search for highly effective etiologic treatment and making it available within the state-financed programs.

Background:Epidemiological characteristics of chronic hepatitis C virus (HCV) infection presented in the literature are not representative for the real situation with its incidence and prevalence in the Russian Federation. In the Moscow Region, which is the second largest population in the Russian Federation (7.2 million people), the Moscow Regional Registry of patients with hepatic disorders has been continuously maintained since 2010, as well as screening programs for anti-HCV positive individuals. Analysis of this data allows for generalization of the results obtain to the general population and for description of the prevalence of the infection among adult population of the Russian Federation.Aim:To analyze the epidemiological situation with chronic hepatitis C in the Moscow Region.Materials and methods:We analyzed data from the Moscow Regional Registry of patients with hepatic disorders as per April 2016, as well as the results of large scale screening of the population of the Moscow Region with oral express test for anti-HCV antibodies (OraQuick HСV Rapid Antibody Test). Based on the registry, we assessed the following parameters of the patient cohort with chronic HCV infection (n = 17 182): age, gender, HCV genotype, grade of liver fibrosis, allele variants of interleukin 28В. Within the large scale screening program among the population of the Moscow Region, 1447 individuals from 6 districts of the region were screened for anti-HCV antibodies.Results:As per April 2016, the proportion of patients with chronic viral hepatitis in the Registry was 75.3% (n = 12 938 of 17 182). The vast majority of them (80.3%, or n = 10 393) had chronic hepatitis C, with 84% (n = 8726) of referrals were patients of productive age (from 20 to 50 years). 8.4% (n = 873) of all HCV infected patients had liver cirrhosis. Although the proportion of patients with cirrhosis was negligibly low (< 1.5%) in patients below 30 years of age, it was progressively increasing with age, with a maximum of 23.8% in those above their 50-es. As far as the HCV genotype distribution is concerned, it was as follows: genotype 1, 54.1% (n = 5622) of patients, genotype 2, 7.2% (n = 747), genotype 3, 38.4% (n = 3990). According to the results of assessment of IL28B genetic polymorphisms (n = 3212), СС rs12979860, which is associated with the most favorable sensitivity to interferon α, was found in 27.5% (n = 883), СТ allele, in 58.4% (n = 1876), and ТТ in 14,1% (n = 453). Prevalence of HCV infection in the Moscow Region, assessed by the screening program, is 1.38% of adults, or 77 200 anti-HCV positive persons, whereas estimated number of patients with chronic hepatitis C may amount to 54 000 to 61 700.Conclusion:HCV infection is the most prevalent among other viral hepatites in the Moscow Region (80.3%), and the largest numbers of infected individuals are of productive age. Almost three quarters of these patients are referred for medical care at the stage of minimal liver injury, and antiviral therapy can be used on an elective basis. Knowing the proportion of patients with liver cirrhosis (8.4%) allows for planning of the need in emergency treatments. The true prevalence of HCV infection estimated from the results of the screening program is at least 5-fold higher than that in the Registry. This indicates the necessity to upgrade the system of primary assessments. In particular, it seems reasonable to include detection of anti-HCV antibodies into the list of obligatory screening laboratory tests.

Treatment of chronic hepatitis B during pregnancy is an extremely complicated issue. Despite implementation of immune prophylaxis, a significant proportion of babies born by mothers with high viral load are infected by hepatitis B virus. Cumulative data suggest that antiviral therapy in the 3 trimester of pregnancy is an effective intervention in the event of unsuccessful immune prord phylaxis. To minimize fetal effects of nucleoside and nucleotide analogues, antiviral therapy during pregnancy should be administered to mothers with high risk of disease progression and/or uncontrolled hepatitis B virus infection. The safety data obtained indicate that telbivudine and tenofovir can be used during pregnancy. Nevertheless, antiviral therapy requires a thorough assessment of the risk to benefit ratio.

High-order surface diffraction gratings acting as a distributed Bragg reflector (DBR) in mesa stripe semiconductor lasers (λ = 1030 nm) have been studied theoretically and experimentally. Higher order interfering radiation modes (IRMs), which propagate off the plane of the waveguide, have been shown to have a crucial effect on the reflection and transmission spectra of the DBR. The decrease in the reflectivity of the DBR in response to the increase in the diffraction efficiency of these modes may reach 80% and more. According to theoretical analysis results, the intensity of the higher order IRMs is determined by the geometry of the DBR groove profile. Experimental data demonstrate that the noncavity modes are responsible for parasitic light leakage losses in the laser cavity. It has been shown that, in the case of nonoptimal geometry of the grating groove profile, the overall external differential quantum efficiency of the parasitic laser emission may exceed 45%, which is more than half of the laser output power. The optimal geometry of the DBR groove profile is trapezoidal, with the smallest possible lower base. Experimental evidence has been presented that this geometry considerably reduces the power of the higher order IRMs and minimises the parasitic light leakage loss.

A method of studying the absorption coefficient in layers of semiconductor lasers is proposed. Using lasers based on MOVPE-grown separate-confinement heterostructures with a broadened waveguide, the absorption coefficient is investigated under pulsed current pumping. It is found that when the pump current flows through the laser in question, an additional internal optical absorption arises in the heterostructure layers. It is shown that an increase in the pump current density up to 20 kA cm-2 leads to an increase in absorption up to 2.5 cm-1. The feasibility of studying free-carrier absorption in the active region is demonstrated.

It was studied in systems constituted by aqueous solutions of 1,2,4-triazole, and NiO and Fe2O3 adsorbents how the electrokinetic potential of the surface of the oxides, amount of adsorbed triazole, and its concentration in solution vary during a long time.

This study aimed to examine anti hepatitis C virus (HCV) antibody titres, their changes and differences in acute, chronic and past HCV infection and to examine them after IFN-alpha-therapy. Ninety five patients were studied in a cross-sectional investigation and 18 of them were followed long-term. Titres of IgM and IgG antibodies against core, NS3, NS4 (A + B), NS5A proteins were determined by the third generation enzyme immunoassays. Patients with acute hepatitis C developed IgG antibodies against core protein in titres 1/5-1/800 and against individual NS proteins at the same titres. During the first to second month of acute hepatitis C IgG antibody titres to HCV proteins were very low, but they had risen considerably by the fourth to sixth month. Anti-HCV IgM antibodies were found in half the acute hepatitis serum samples, titres were 1/5-1/40. Sixty individuals with chronic hepatitis C showed IgG antibodies against core in titres 1/800-1/40,000 and against individual NS proteins in titres 1/5-1/20,000. Eight patients with chronic hepatitis C had invariable anti-HCV IgG antibodies over 2-3 years. About 81.7% of chronically infected patients had anti-HCV IgM antibodies in titres 1/5-1/160. Patients with resolution of HCV infection showed only anti-core IgG antibodies (titres 1/5-1/200) or no virus-specific antibodies. Individuals with different response to IFN-alpha-therapy showed two distinct patterns of anti-HCV antibody titres. Acute and chronic HCV infection may be distinguished by anti-core titres.

To study effectiveness of recombinant interferon-alpha (Ifna) in patients with chronic hepatitis C with normal transaminases.26 patients with positive tests for abHCV and RNA HCV with a normal level of alaninaminotransferase (AlAT) entered the study. 16 patients of the test group received recombinant Ifna three times a week in a dose 3 mln IU. Mean duration of interferon therapy was 7.44 +/- 4.27 months. Control group consisted of 10 patients with natural course of the disease. Biochemical, virusological and morphological examinations were conducted in all the patients. The patients were followed up for 1.5-2 years, on the average.Treatment with recombinant Ifna was well tolerated. A persistent positive virusological response after the treatment was achieved in 25% of the test patients. They exhibited improvement of histological structure of the liver. In control group the dynamics was opposite.In patients with chronic hepatitis C with normal transaminases level interferon therapy improves structure of hepatic tissue. Puncture biopsy of the liver is the main method which determines the validity of the treatment and its efficacy.