396 research outputs found

    A uniqueness result for the inverse problem of identifying boundaries from weighted Radon transform

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    We study the problem of the integral geometry, in which the functions are integrated over hyperplanes in the nn-dimensional Euclidean space, n=2m+1n=2m+1. The integrand is the product of a function of nn variables called the density and weight function depending on 2n2n variables. Such an integration is called here the weighted Radon transform, which coincides with the classical one if the weight function is equal to one. It is proved the uniqueness for the problem of determination of the surface on which the integrand is discontinuous.Comment: 10 pages, 1 figur

    Donors of effective genes for scald resistance in barley

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    Background. One of the most harmful diseases of barley in all areas of its cultivation is scald. The causal agent Rhynchosporium commune Zaffarano, B.A. McDonald & A. Linde (formerly – Rhynchosporium secalis (Oudem.) J.J. Davis) is characterized by a high level of variability, which leads to the emergence of new pathotypes and the loss of resistance of a number of cultivars. Most barley cultivars recommended for cultivation are highly affected by the pathogen. The aim of the study was to find new donors of effective barley resistance genes to R. commune.Materials and methods. Resistance to the fungus was tested in 99 accessions of barley landraces from 18 countries under laboratory and field conditions. The experiments employed isolates and clones of R. commune isolated from plants collected in Leningrad Province. Plant resistance was scored using point scales. Genetic control of fungal resistance was studied in the selected accessions using hybridological analysis.Results and conclusions. We identified 3 accessions of barley landraces, which retained high resistance to the fungus for six years of study in the field under inoculation with different populations of R. commune. Accessions k-31504 (Macedonia), k-31505 (Ethiopia) and k-31503 (India) are protected by R. commune resistance genes, which differ from each other, are not allelic to the previously identified effective Rrs9 gene, and manifest themselves throughout all stages of barley ontogenesis. Each of accessions k-31504 and k-31505 incorporates 2 recessive pathogen resistance genes; k-31503 carries 3 recessive resistance genes

    Genetic control of scald resistance in barley landraces

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    Scald (Rhynchosporium secalis (Oudem.) J.J. Davis pathogenic agent) is one of the most harmful barley diseases. A high variability of this fungi explains the occurrence of new aggressive pathotypes and, accordingly, loss of cultivar resistance. It was found that many recently selected varieties of barley and previously identified sources of resistance to R. secalis are now susceptible to the pathogen. There is only one gene, Rrs9, that maintains efficiency against pathogen populations in Russia. The aim of this study is to find donors of genes for effective resistance to scald with the ability to easily transfer this trait for hybridization. The inheritance of scald resistance in 33 barley landraces was studied. Analysis of the interaction between the pathogen test clones and the host plant revealed a difference between the alleles determining fungal resistance in 32 barley forms, the previously effective genes Rrs4, rrs6, rrs7, and currently effective Rrs9. It was found that 30 accessions are protected by new unidentified genes for scald resistance. Accessions k-18398 and k-16231 from China are likely to possess allelic genes for scald resistance, while the gene (or genes) of accession k-31075 from Nepal is allelic to the Rrs9 gene. It was demonstrated by hybridological analysis that accessions k-3307, k-15868, k-18989 and k-3481 are protected by effective genes for scald resistance, which differ from each other and which are not allelic to the Rrs4, rrs6, rrs7 or Rrs9 genes. Accessions k-15868 and k-3481 possess two complementary recessive genes for scald resistance, k-18989 has two recessive genes, and k-3307 carries one recessive gene for pathogen resistance. The resistance genes of these forms are manifested during all the stages of plant ontogenesis

    LITHOLYTIC THERAPY AT THE TREATMENT OF CHOLELITHIASIS (REVIEW OF LITERATURE)

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    Treatment of cholelithiasis in patients with high operative risk need requires minimally invasive methods. Contact bilestones litholysis is a perspective direction. For this purpose it is recommended to use medications with the highest litholytic activity and the lowest side effects. It is necessary to seek for an adequate concrement dissolvent because of mineral and organic composition of bilestones. The article presents comparative analysis of characteristics of various dissolving agents proceeding from effectiveness and intensity toxic effects

    DIAGNOSTICS OF HELICOBACTER PYLORI INFECTION BY ENZYME IMMUNOASSAY IN PATIENTS WITH CALCULOUS CHOLECYSTITIS

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    In recentyears, the interest in the significance of Helicobacter pylori in various pathological processes is growing. The most studied is the role of Helicobacter pylori in gastroduodenal pathology. Gallstone disease is one of the most common diseases of the digestive system. Inflammatory changes in the biliary tract aggravate the clinical course of gallstone disease both in the preoperative and in the postoperative period and cause strictures, deformations of the extra hepatic bile ducts in the long term. One of the most threatening complications of gallstone disease is acute cholecystitis. Determination of IgG to Helicobacter pylori in complex diagnosis is important in patients with calculous cholecystitis. We conducted a prospective study of patients (n = 105) aged 30 to 50 years, suffering from different variants of calculous cholecystitis, in the preoperative and postoperative period by enzyme immunoassay. Enzyme-linked immunosorbent assay is reliable, affordable, least invasive method for diagnosing H. pylori infection. In patients with calculous cholecystitis, we marked a significant increase in IgG antibodies to Helicobacter pylori before surgical intervention and a subsequent reduction 10 days after it. Diagnosis of Helicobacter pylori infection of the gallbladder increases therapeutic efficiency and helps to develop preventive measures for complications of gallstone disease

    1-(8-Bromo-2-methyl-4-thioxo-3,4,5,6-tetra­hydro-2H-2,6-methano-1,3-benzoxazocin-11-yl)ethanone

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    In the title compound, C14H14BrNO2S, there are two similar non-equivalent mol­ecules in the asymmetric unit, displaying three chiral centres each. In the crystal structure, they are linked by inter­molecular N—H⋯O hydrogen bonds to form infinite chains, which are in turn connected by weak Br⋯H and S⋯H inter­actions

    The energy gap of intermediate-valent SmB6 studied by point-contact spectroscopy

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    We have investigated the intermediate valence narrow-gap semiconductor SmB6 at low temperatures using both conventional spear-anvil type point contacts as well as mechanically controllable break junctions. The zero-bias conductance varied between less than 0.01 mikrosiemens and up to 1 mS. The position of the spectral anomalies, which are related to the different activation energies and band gaps of SmB6, did not depend on the the contact size. Two different regimes of charge transport could be distinguished: Contacts with large zero - bias conductance are in the diffusive Maxwell regime. They had spectra with only small non-linearities. Contacts with small zero - bias conductance are in the tunnelling regime. They had larger anomalies, but still indicating a finite 45 % residual quasiparticle density of states at the Fermi level at low temperatures of T = 0.1 K. The density of states derived from the tunelling spectra can be decomposed into two energy-dependent parts with Eg = 21 meV and Ed = 4.5 meV wide gaps, respectively.Comment: 9 pages incl. 13 figure

    Clearance of carbonyl-modified lipoproteins from the bloodstream of rabbits

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    We have suggested that the molecular mechanism of vascular wall damage in diabetes is not substantially different from that in atherosclerosis. Thus, it can be assumed that aldehyde-modified LDL should be eliminated from the blood stream with much greater speed than non-oxidized LDL. In the available literature there is information about the clearance of native human LDL from the bloodstream, whereas information on the clearance of the aldehyde-modified LDL in animals or humans was not found. Based on this, the present work is devoted to the clearance of aldehyde-modified LDL of rabbits and humans introduced into the bloodstream of rabbits. We investigated the clearance of glyoxal-, methylglyoxal- and MDA-modified LDL from the bloodstream of rabbits. We used biotinylated LDL of rabbit blood plasma and FITC-labeled LDL of human blood plasma. LDL was isolated with preparative ultracentrifugation in NaBr gradient. It was shown that glyoxal- and methylglyoxal-modified LDL of rabbits and humans circulated in the bloodstream for the same time as native LDL while MDA-modified LDL was rapidly eliminated from the bloodstream. The data obtained indicated the possibility of greater atherogenic potential of glyoxal- and methylglyoxal-modified LDL as they circulate in the bloodstream for a rather long time. At the same time, MDA-modified LDL is likely to be exposed to enhanced elimination by macrophages after their "linkage" to blood cells

    OPTIMIZATION OF METHODS FOR DIAGNOSTICS OF PATIENTS WITH TOXIC AND CIRRHOTIC LIVER LESIONS

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    Chronic liver disease is a serious problem for public health service. As a result of increasing alcoholization of population, drug addiction, number of patients with parenteral hepatitis (B, C, D) the conditions for significant increase of number of patients with hepatocirrhosis appear. The aim. of our study was to determine the most optima! methods of diagnostics of patients with toxic and cirrhotic lesions of liver. The object of the research was 67 patients treated, in Irkutsk Municipal Clinical Hospital N 1 during 2007—2011 years with liver cirrhosis. All the patients had. diagnostic laparoscopy with determination. of the level of cytokines, albumins and. gamma-globulins with further clinicomorphological and. statistical analysis of the results. It was revealed that complex use of instrumental and. laboratory methods allows to diagnose liver cirrhosis at the early stage of its progress very precisely.

    Preoperative method of assessment of gallbladder lesion in acute cholecystitis

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    Background. To date acute cholecystitis remains one of the most common urgent abdominal diseases in which postoperative complications and mortality are possible.The aim. To assess the correlation of gamma-glutamyltranspeptidase and alkaline phosphatase concentrations in blood plasma with the form of acute cholecystitis.Methods. A study of 105 patients with acute calculous cholecystitis, 35 – with chronic calculous cholecystitis (comparison group), who underwent laparoscopic cholecystectomy, was performed. At admission to the hospital, the activity of gammaglutamyltranspeptidase (GGTP) and alkaline phosphatase in blood plasma was determined by kinetic colorimetric method.Results. A direct correlation was revealed between the level of GGTP concentration and the severity of destruction in the gallbladder wall. With catarrhal cholecystitis, it was 340 ± 116.9 U/l (p < 0.05), with phlegmonous – 108.1 ± 29.5 U/l (p < 0.05), with gangrenous – 32.9 ± 7.5 U/l (p < 0.05). Along with this, a direct correlation was revealed between the concentration of alkaline phosphatase and the severity of destruction in the gallbladder wall. In catarrhal cholecystitis, the enzyme activity was 160.3 ± 34.2 U/l (p < 0.05), in phlegmonous – 129.9 ± 14.6 U/l (p < 0.05), in gangrenous – 57 ± 18.5 U/l (p < 0.05).Conclusion. Determination of the concentration of GGTP and alkaline phosphatase in combination with other diagnostic criteria makes it possible to determine the presence of destructive forms of acute cholecystitis with high specificity and sensitivity before surgery
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