913 research outputs found
Medium effects in the production and pi0 gamma decay of omega-mesons in pA collisions in the GeV region
The omega-resonance production and its pi0 gamma decay in p-A reactions close
to threshold is considered within the Intranuclear Cascade (INC) Model. The pi0
gamma invariant mass distribution shows two components which correspond to the
omega decay 'inside' and 'outside' the nucleus, respectively. The 'inside'
component is distorted by medium effects, which introduce a mass shift as well
as collisional broadening for the omega-meson and its decaying pion. The
relative contribution of the 'inside' component is analyzed in detail for
different kinematical conditions and nuclear targets. It is demonstrated that a
measurement of the correlation in azimuthal angle between the pi0 and gamma
momenta allows to separate events related to the 'inside' omega decay from
different sources of background when uncorrelated pi0's and gamma's are
produced.Comment: 24 pages, 11 figure
Исследования микроспоридий рода Nosema в Томской области (Сибирь): ко-инвазия широко распространена в пчелиных семьях
Microsporidian protozoans Nosema are gut parasites that infect European honeybees (Apis mellifera) worldwide. In the Tomsk region, two species of microsporidia were registered in honeybees (A. mellifera): N. apis and N. ceranae. During the last 6 years, an increase in infections by Nosema in honeybees has been detected in the Tomsk region, while cases of mass bee colony deaths were rare (in 2016, two cases of winter losses of bee colonies in the northern districts of the Tomsk region have been reported by beekeepers). The infestation of bee colonies and apiaries have changed from 0% in 2012 to about 80% in 2016-2017. In 2013-2014, 60.0% of all infected apiaries were infected only with N. apis. In 2015-2017, most of the infected apiaries (52.2%) were infected with both species of microsporidia. Despite the predominance of co-infection in honeybees, replacement of N. apis by N. ceranae is not observed
CASTOR: Centauro and Strange Object Research in nucleus-nucleus collisions at LHC
We describe the CASTOR detector designed to probe the very forward,
baryon-rich rapidity region in nucleus-nucleus collisions at the LHC. We
present a phenomenological model describing the formation of a QGP fireball in
a high baryochemical potential environment, and its subsequent decay into
baryons and strangelets. The model explains Centauros and the long-penetrating
component and makes predictions for the LHC.
Simulations of Centauro-type events were done. To study the response of the
apparatus to new effects different exotic species (DCC, Centauros, strangelets
etc.) were passed through the deep calorimeter. The energy deposition pattern
in the calorimeter appears to be a new clear signature of the QGP.Comment: Talk given by E. Gladysz-Dziadus for the CASTOR group, Intern.
Workshop on Nuclear Theory, 10-15 June, 2002, Bulgaria, Rila Mountains, 15
pages, 14 figure
Neutron-antineutron Oscillations in the Trapping Box
We have reexamined the problem of oscillations for ultra-cold
neutrons (UCN) confined within a trap. We have shown that the growth of the
component with time is to a decent accuracy given by where is the mixing parameter,
sec in the neutron propagation time between subsequent collisions
with the trap walls. Possible corrections to this law and open questions are
discussed.Comment: 11 pages, LaTeX2
Construction of stably maintained non-mobilizable derivatives of RSF1010 lacking all known elements essential for mobilization
<p>Abstract</p> <p>Background</p> <p>RSF1010 is a well-studied broad-host-range plasmid able to be mobilized to different bacteria and plants. RSF1010-derived plasmid vectors are widely used in both basic research and industrial applications. In the latter case, exploiting of mobilizable plasmids or even the plasmids possessing negligible mobilization frequency, but containing DNA fragments that could promote conjugal transfer, is undesirable because of biosafety considerations. Previously, several mutations significantly decreasing efficiency of RSF1010 mobilization have been selected. Nevertheless, construction of the RSF1010 derivative lacking all known loci involved in the conjugal transfer has not been reported yet.</p> <p>Results</p> <p>Novel non-mobilizable derivatives of RSF1010 lacking all known DNA sequences involved in the mobilization process have been obtained due to the exploiting of λRed-driven recombination between the plasmid and a constructed <it>in vitro </it>linear DNA fragment. To provide auto-regulated transcription of the essential replication gene, <it>repB</it>, the plasmid loci <it>oriT</it>, <it>mobC </it>and <it>mobA </it>were substituted by the DNA fragment containing P<sub><it>lac</it>UV5</sub>→<it>lacI</it>. Mobilization of the obtained RSFmob plasmid was not detected in standard tests. The derivative of RSFmob with increased copy number has been obtained after <it>lacI </it>elimination. High stability of both constructed plasmids has been demonstrated in <it>Escherichia coli </it>and <it>Pantoea ananatis</it>. Design of RSFmob allows easy substitution of P<sub><it>lac</it>UV5 </sub>by any desirable promoter for construction of novel derivatives with changed copy number or host range.</p> <p>Conclusion</p> <p>Novel non-mobilizable derivatives of RSF1010 lacking all known DNA sequences involved in the mobilization process and stably maintained at least in <it>E. coli </it>and <it>P. ananatis </it>have been constructed. The obtained plasmids became the progenitors of new cloning vectors answering all biosafety requirements of genetically modified organisms used in scale-up production.</p
ANALYSIS OF RW HANDLING IN FOREIGN COUNTRIES
В работе рассмотрен вопрос организации системы обращения с РАО в некоторых зарубежных странах, приведено их сравнение. Кратко описаны проекты по обращению с РАО, приведена их стоимость. Сделан вывод о том, какие действия необходимо предпринять в нашей стране для предотвращения возможных проблем, связанных с РАО.The paper discusses the issue of organizing a radioactive waste (RW) management system in some foreign countries and gives their comparison. RW management projects are briefly described, their cost is given. The conclusion is made about what actions should be taken in our country to prevent possible problems associated with radioactive waste
The investigation of dangerous geological processes resulting in land subsidence while designing the main gas pipeline in South Yakutia
The number of gas main accidents has increased recently due to dangerous geological processes in underdeveloped areas located in difficult geological conditions. The paper analyses land subsidence caused by karst and thermokarst processes in the right of way, reveals the assessment criteria for geological hazards and creates zoning schemes considering the levels of karst and thermorkarst hazards
Modulating effect of Cu(II) complexes with enamine and tetrazole derivatives on CYP2C and CYP3A and their cytotoxic and antiproliferative properties in HepG2 spheroids
CYP2C and CYP3A cytochromes are induced by a variety of compounds and affect the pharmacokinetics and pharmacodynamics of a large number of drugs. Currently, the possibility of using copper coordination compounds in antitumor therapy is being actively studied. Evaluation of potential interactions between new molecules and P450 cytochromes is necessary at an early stage of drug design.The aim. To study the modulating effect of Cu(II) complexes with enamine and tetrazole derivatives on CYP2C9, CYP2C19 and CYP3A4 and their cytotoxic and antiproliferative properties on normal human lung fibroblasts MRC-5 and a 3D model of hepatocellular carcinoma HepG2.Materials and methods. Cytotoxic and antiproliferative activities of copper(II) complexes – [CuL2] (1), [Cu2(bipy)2(PT)4] (2), [Cu2(phen)2(PT)4] (3), {[Cu(phen)(MT)2]∙H2O}n (4) (L – anion of 2-anilinomethylidene-5,5-dimethylcyclohexane-1,3-dione; PT – 5-phenyltetrazolate anion; MT – 5-methyltetrazolate anion; bipy – 2,2’-bipyridine; phen – 1,10-phenanthroline) – were examined in 2D and 3D models using fluorescence-based phenotypic screening. The modulating effect on CYP2C9, CYP2C19 and CYP3A4 was studied using fluorescence-based targeted screening. The results of CYP3A4 expression were confirmed by real-time reverse transcription polymerase chain reaction (RT-PCR).Results. Complex (1) increases the CYP3A4 expression and does not affect CYP2C9 and CYP2C19 expression. Complex (2) has no modulating effect on CYP2C and CYP3A. Complexes with 1,10-phenatrolin (3) and (4) induce CYP3A4, inhibit CYP2C9 and do not affect CYP2C19 expression. All compounds have a dose-dependent cytotoxic effect on HepG2 and MRC-5: the compound with 5-methyltetrazolate anion (4) has the same effect on cell lines, compounds with 5-phenyltetrazolate anion (2) and (3) have selective effect. Complexes with 1,10-phenatrolin are effective on both 2D and 3D models.Conclusion. The [Cu2(phen)2(FT)4] complex (3) can be used as a basis for creating an antitumor compound, but further modification of the structure is required to increase the selectivity to tumor cells
Maternal incompatibilities with fetal human platelet alloantigens -1a, -1b and -15 are the main causes of neonatal alloimmune thrombocytopenia in Russia
The aim. Mechanisms underlying the development of neonatal alloimmune thrombocytopenia (NAIT) in in Russia have been studied. Materials and methods. Genetic polymorphisms of human platelet alloantigens (HPA) -1, -2, -3, -4, -5, and -15 were evaluated in 27 families having the newborns with NAIT. NAIT was diagnosed according to the following criteria: (1) newborn with thrombocytopenia; (2) mother with no thrombocytopenia and no increase of platelet associated IgG, (3) presence of antibodies reacting with paternal platelets in maternal plasma / serum. HPA genotyping revealed incompatibilities in 23 out of 27 tested families. In these 23 families HPA-1 conflicts were detected in 16 ones (70%). In 8 cases mothers were homozygous carriers of rare HPA-1b allele and in another 8 cases - of HPA-1a allele which cased incompatibilities with fetal HPA-1a and HPA-1b respectively. In 5 out of 23 families (22%) there were incompatibilities with fetal HPA-15 (HPA-15a, n=2 and HPA-15b, n=3), in 1 family - with HPA-5b (4%), and in 1 family - with HPA-3b (4%) alloantigens. In conclusion the main causes of NAIT in Russia were HPA-1a and -1b conflicts and HPA-15 conflicts were the second frequent ones
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