7,854 research outputs found
Model DNA for investigation of mechanism of nucleotide excision repair
The living cell DNA is under permanent attack of a variety of exogenous and endogenous damaging factors. Nucleotide excision repair (NER) is main pathway which removes a wide variety of bulky DNA adducts formed by UV light, electrophilic environmental mutagens, and chemotherapeutic agents. NER process in mammalian cells consistently leads to the very specific excision of damaged DNA fragments 24–32 nucleotides in length. The following DNA repair synthesis and DNA ligation restore intact DNA helix. The main set of the genes inactivated in NER-deficient higher eukaryotic cells was identified; about 30 proteins are involved in the specific multi-subunit complexes responsible for NER process. The specific NER feature is wide substrate specificity and great difference of damages elimination efficiencies. A key limiting step in NER is damage recognition and verification. One of the advanced and upcoming approaches to NER process investigation is based on the application of model DNAs – artificial DNA structures, which are analogs of substrate or intermediates of the repair process. This article reviews our current knowledge concerning the model DNA design, synthesis and application as a tool for the NER process comprehensive study
Density Anomalies in Crude Oil Blends Reflect Multiple Equilibrium States of Asphaltene Colloidal Aggregates
Density measurements revealed anomalies of nonideality (maxima of excess density) at some compositions in binary blends of light and heavy crude oils from diverse origins. By IR absorption measurements, density anomalies were attributed to increased contents of suspended asphaltene colloidal-sized particles/aggregates in the blends. By comparison with a database of world’s native crude oils, it was concluded that density anomalies may correspond to different equilibrium structural states of asphaltene colloids that occur at several specific asphaltene contents, apparently common for petroleum media of any origin
Analysis of Involvement of Cytokine Genetic Polymorphisms in Development of Genital Endometriosis
The article outlines the role of cytokines in development of genital endometriosis. There were detected associations between genetic polymorphisms and their combinations and development of genital endometriosis among women in the Central region of Russi
Candidate genes and clinical-laboratory parameters in pregnant women with preeclampsia
They studied the associations of genetic polymorphisms with clinico-laboratory indicators among pregnant women with preeclampsia depending on hereditary complicatio
Vendian age of igneous rocks of the Chamberlain valley area (Northern part of the Wedel Jarlsberg Land, Svalbard Archipelago)
The geological structure, structural relations with the underlying complexes, mineral composition, age and origin of sedimentary-volcanogenic and intrusive formations of the Chamberlain valley area (northern part of the Wedel Jarlsberg Land, Svalbard Archipelago) are considered. As a result of the studies, two stages of the Late Precambrian endogenous activity in this area have been identified. For the first time the Vendian ages (593-559 Ma) of intrusive (dolerites) and effusive (basalts, andesites, tuffs) rocks were determined by U-Pb-method (SHRIMP-II) for Svalbard Archipelago. At the same time, the Grenville ages for large bodies of gabbro-diorites, metadolerites bodies (1152-967 Ma), and metagranites (936 Ma) were determined for the first time for this area, which correlates well with the ages of magmatic formations obtained earlier in the southern part of Wedel Jarlsberg Land. A detailed petrographic and petrochemical characterization of all the described objects were compiled and the paleotectonic conditions of their formation were reconstructed. Based on these data, the Chemberlendalen series, which is dated to the Late Vendian, and the Rechurchbreen series, which the authors attribute to the Middle Riphean and correlate with the lower part of the Nordbucht series are distinguished. The data obtained indicate a two-stage Precambrian magmatism in this area of the Svalbard archipelago and, most importantly, provide evidence for the first time ever of endogenous activity on Svalbard in the Vendian time. This fact makes it possible to reconsider in the future the history of the formation of folded basement of the Svalbard archipelago and the nature of the geodynamic conditions in which it was formed
Identification method based on Zadeh filter models
Mathematical modeling which provides the description of objects and proper organization of control operations in future is an integral stage in the automation of production. One of the approaches to build a mathematical model of an object is to represent nonlinear systems as combinations of inertial and nonlinear inertialess elements. The models thus obtained are called block-oriented. In this paper, we consider nonlinear dynamic objects represented as the models of the Zadeh filter class. In the process of the method development the identification equations were derived for the case when the test signal is a single sinusoid. Then the case of two sinusoids was considered. Such investigations allowed us to identify the patterns and describe the general case for several test components in the signal. The results of digital modeling using the sum of harmonic signals confirm the feasibility and validity of the proposed approach for identifying nonlinear models of the Zadeh filter class
The role of chemokine genes in the formation of terminal stage of chronic renal failure
The data on the role of chemokine genes (+1931A/T CCL4, A/G CXCL11 (rs4512021), -403A/G CCL5, C/G CCL2 (rs2857657), -801G/A CXCL12) in the formation of terminal stage of chronic renal failure, in patients with chronic glomerulonephritis, is presented in the work. It was established, that the allele A CXCL11 (rs4512021) (OR = 1.65) was the marker for the development of terminal stage of chronic renal insufficiency, and the genotype GG CXCL11was a protective factor for the development of terminal stage of chronic renal failure (OR = 0.22
Associations of Cytokines Genetic Variants with Myomatous Knots Sizes
The article presents study of cytokines molecular genetic markers’ impact on nature of uterus affection with myomatous knot
Carbon Friction Pair in Total Hip Replacement
The article examines the advantages of a new pair of friction of the hip joint endoprosthesis made of pyrolytic carbon. The physico-mechanical and tribological characteristics of the material and their comparison with other materials used in the friction pair of hip joint endoprostheses are presented. Information is presented about the making of a material and its strength characteristics and the results of mathematical modeling of a friction pair. The results of a comparative research of the durability between a carbon pair of friction and a ceramic pair of friction
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