107 research outputs found
Reconstruction of recombination sites in genomic structures of the strains of genotype 6 of hepatitis C virus
The encoded portion of the complete genomes of 46 strains of the genotype 6 of hepatitis C virus through bioinformatics RDP programs complex group of 6 recombinants strains was identified, in which 7 recombination sites were fixed. Strains correspond to the three-recombinant HCV subtypes: 6a, 6b and 61. For each of the identified recombinant we defined parent strains from which they can be obtained. Three recombinants were obtained from parent strains of the same subtype (homologous inside subgenotypic recombination). For the remaining three recombinants parent strains were members of three different subtypes (between subgenotypic recombination).In one strain we identified a unique recombination site in a highly conservative NS3 gene. Most of the recombination sites occurred in the region of the structural genes C, E1 and E2, and in the area of non-structural genes NS5a and NS5b.In the recombinant strain DQ480518-6a two recombination site were identified. One site is located in the structural and nonstructural genes (E2 + NS1 + NS2), and a second one in non-structural region. Dimensions of recombination sites can vary from 86 to 1072 nucleotide bases. The study identified "hot spots" of recombination in the strains of genotype 6 of hepatitis C virus. The recombinants were found in the population of the three countries: the United States (from the serum of an immigrant), Hong Kong and China
HCV Infection in the Republic of Sakha (Yakutia) and Its Role of Genotypes in Clinical Outcomes of the Disease
Aim of the research. To study the epidemic manifestations of HCV infection in the Republic of Sakha (Yakutia) in order to develop recommendations for improving the effectiveness and quality of treatment and prevention measures. Materials and methods. The paper uses materials from the official statistics of the Territorial Department of Rospotrebnadzor of the Republic of Sakha (Yakutia) for 1994–2018, and data from the electronic register «Chronic viral hepatitis in the RS (Ya)» (2019). Molecular and biological studies of the genotype of the hepatitis C virus were performed jointly on the basis of the Federal state budgetary Institution «Central research Institute of epidemiology» of Rospotrebnadzor (2007–2011, n = 75). To assess the epidemiological situation, the rate of increase in morbidity is calculated on the basis of data equalized by the method of least squares. Statistical processing was performed using the SPSS 17 program. The critical significance level is assumed to be 0.05. Results. Thus, the study of long-term dynamics of the incidence of viral hepatitis shows that in the Republic of Sakha (Yakutia) a consistently high level of incidence of HCV with adverse trends in the development of the epidemic process remains. Analysis of the distribution of different variants of HCV genotypes allowed us to establish the prevalence of genotype 1b, which can determine the high frequency of cirrhosis and primary liver cancer. The current situation in the Republic regarding the incidence of viral hepatitis requires detailed monitoring, improvement of epidemiological surveillance and introduction of modern treatment methods. It is also necessary to improve the quality of health education among the population of the Republic
GEMINGA: NEW OBSERVATIONS AT LOW RADIO FREQUENCIES
ABSTRACT. After nearly 10 years, we have succeeded to detect radio emission from Geminga more again. In this report we present new evidence for presence of radio emission from Geminga in the range 42-112 MHz. The observations were carried out on two sensitive transit radio telescopes We used three new digital receivers to detect the pulses and to obtain dynamic spectra.The examples of mean pulse profiles are presented. Exact value of the dispersion measure have been calculated using the simultaneous observations at three frequencies
Absolute Negative Conductivity in Two-Dimensional Electron Systems Associated with Acoustic Scattering Stimulated by Microwave Radiation
We discuss the feasibility of absolute negative conductivity (ANC) in
two-dimensional electron systems (2DES) stimulated by microwave radiation in
transverse magnetic field. The mechanism of ANC under consideration is
associated with the electron scattering on acoustic piezoelectric phonons
accompanied by the absorption of microwave photons. It is demonstrated that the
dissipative components of the 2DES dc conductivity can be negative
() when the microwave frequency is
somewhat higher than the electron cyclotron frequency or its
harmonics. The concept of ANC associated with such a scattering mechanism can
be invoked to explain the nature of the occurrence of zero-resistance
``dissipationless'' states observed in recent experiments.Comment: 7 pager, 2 figure
On the connection between gamma and radio radiation spectra in pulsars
The model of pulsar radio emission is discussed in which a coherent radio
emis-sion is excited in a vacuum gap above polar cap of neutron star. Pulsar X
and gamma radiation are considered as the result of low-frequency radio
emission inverse Comp-ton scattering on ultra relativistic electrons
accelerated in the gap. The influence of the pulsar magnetic field on Compton
scattering is taken into account. The relation of radio and gamma radiation
spectra has been found in the framework of the model.Comment: 15 pages, 3 figures, Russian version accepted to JETP, partly
published in JETP Letters, Vol. 85, #6 (2007
Nonlinear effects in microwave photoconductivity of two-dimensional electron systems
We present a model for microwave photoconductivity of two-dimensional
electron systems in a magnetic field which describes the effects of strong
microwave and steady-state electric fields. Using this model, we derive an
analytical formula for the photoconductivity associated with photon- and
multi-photon-assisted impurity scattering as a function of the frequency and
power of microwave radiation. According to the developed model, the microwave
conductivity is an oscillatory function of the frequency of microwave radiation
and the cyclotron frequency which turns zero at the cyclotron resonance and its
harmonics. It exhibits maxima and minima (with absolute negative conductivity)
at the microwave frequencies somewhat different from the resonant frequencies.
The calculated power dependence of the amplitude of the microwave
photoconductivity oscillations exhibits pronounced sublinear behavior similar
to a logarithmic function. The height of the microwave photoconductivity maxima
and the depth of its minima are nonmonotonic functions of the electric field.
It is pointed to the possibility of a strong widening of the maxima and minima
due to a strong sensitivity of their parameters on the electric field and the
presence of strong long-range electric-field fluctuations. The obtained
dependences are consistent with the results of the experimental observations.Comment: 9 pages, 6 figures Labeling of the curves in Fig.3 correcte
ОСОБЕННОСТИ ПОЛИМОРФИЗМА ГЕНОВ ИНТЕРФЕРОНА III ТИПА У БОЛЬНЫХ ВИРУСНЫМ ГЕПАТИТОМ С НА СОПРЕДЕЛЬНЫХ ТЕРРИТОРИЯХ РОССИИ И МОНГОЛИИ
Aims: determine the structure of IFNL3/IFNL4 interferon genes’ polymorphism in healthy people and in HCV patients and the frequency of spontaneous viral clearance in ethnic groups of Caucasians and Mongolians, living in the Asian part of Russia (Irkutsk Region) and in Mongolia. Materials and methods: population genetic studies were conducted at 669 patients with hepatitis C, including 567 representatives Caucasian and 102 Mongoloid races. The control group consisted of 1520 healthy individuals, blood donors (800 Caucasians and 720 Mongoloids). Results: it was found that in Caucasians patients with chronic hepatitis C were significantly less common CC genotype rs12979860, TT genotype rs8099917 and TT/TT genotype rs368234815, than in the general population. However, in patients with chronic hepatitis C, the representatives of the Mongoloid race, compared with healthy individuals, significant differences were found only in relation to the TT genotype rs8099917 IFNL3 gene. Spontaneous clearance of the virus was significantly more common in the Mongoloid race than in Caucasians. Conclusions: the spontaneous viral clearance after clinical evidence or latent suffering hepatitis C was significantly more common in the Mongoloid race than in Caucasians that genetically determined high rate of prevalence in the population of the Mongols CC genotype rs12979860, TT genotype rs8099917 and TT/TT genotype rs368234815 polymorphisms of interferon type III genes.Цель исследования: определить структуру полиморфизма генов интерферона IFNL3/IFNL4 у здоровых лиц и больных вирусным гепатитом С и частоту спонтанного клиренса вируса в этнических группах европеоидов и монголоидов, проживающих в азиатской части России (Иркутская область) и Монголии. Материалы и методы: популяционно-генетические исследования проводились у 669 больных хроническим гепатитом С, в том числе у 567 представителей европеоидной и 102 монголоидной рас. Контрольную группу составили 1520 практически здоровых лиц, доноров крови (800 европеоидов и 720 монголоидов). Результаты: обнаружено, что у больных хроническим гепатитом С, представителей европеоидной расы, значимо реже встречались СС-генотип rs12979860, ТТгенотип rs8099917 и ТТ/ТТ-генотип rs368234815, чем в общей популяции здоровых лиц. Вместе с тем, у больных хроническим гепатитом С, представителей монголоидной расы, по сравнению со здоровыми лицами, значимые отличия обнаружены только в отношении ТТ-генотипа rs8099917 гена IFNL3. Спонтанный клиренс вируса значимо чаще (в 1,6 раза) встречался у представителей монголоидной расы, чем у европеоидов. Заключение: спонтанный клиренс вируса после клинически выраженного или латентно перенесенного гепатита С значимо чаще встречается у представителей монголоидной расы, чем у европеоидов, что генетически детерминировано высокой частотой распространенности в популяции монголов СС-генотипа rs12979860, ТТ-генотипа rs8099917 и ТТ/ТТ-генотипа rs368234815 полиморфизмов генов интерферонов III типа
New Measurement of Parity Violation in Elastic Electron-Proton Scattering and Implications for Strange Form Factors
We have measured the parity-violating electroweak asymmetry in the elastic
scattering of polarized electrons from the proton. The result is A = -15.05 +-
0.98(stat) +- 0.56(syst) ppm at the kinematic point theta_lab = 12.3 degrees
and Q^2 = 0.477 (GeV/c)^2. The measurement implies that the value for the
strange form factor (G_E^s + 0.392 G_M^s) = 0.025 +- 0.020 +- 0.014, where the
first error is experimental and the second arises from the uncertainties in
electromagnetic form factors. This measurement is the first fixed-target parity
violation experiment that used either a `strained' GaAs photocathode to produce
highly polarized electrons or a Compton polarimeter to continuously monitor the
electron beam polarization.Comment: 8 pages, 4 figures, Tex, elsart.cls; revised version as accepted for
Phys. Lett.
Measurement of the Generalized Forward Spin Polarizabilities of the Neutron
The generalized forward spin polarizabilities and of
the neutron have been extracted for the first time in a range from 0.1 to
0.9 GeV. Since is sensitive to nucleon resonances and
is insensitive to the resonance, it is expected that the
pair of forward spin polarizabilities should provide benchmark tests of the
current understanding of the chiral dynamics of QCD. The new results on
show significant disagreement with Chiral Perturbation Theory
calculations, while the data for at low are in good agreement
with a next-to-lead order Relativistic Baryon Chiral Perturbation theory
calculation. The data show good agreement with the phenomenological MAID model.Comment: 5 pages, 2 figures, corrected typo in author name, published in PR
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