Efficiency of Electron-Positron Pair Productionby Neutrino Flux from Accretion Disk of a Kerr Black Hole

Dominant processes of neutrino production and neutrino-induced \ep-pair production are examined in the model of a disk hyper-accreting onto a Kerr black hole. The efficiency of plasma production by a neutrino flux from the disk, obtained for the both cases of presence and absence of a magnetic field, is found to be no more than several tenths of percent and, therefore, not enough for the origin of cosmological gamma-ray bursts.Comment: 8 pages, 1 figur

Semiclassical approach to the decay of protons in circular motion under the influence of gravitational fields

We investigate the possible decay of protons in geodesic circular motion around neutral compact objects. Weak and strong decay rates and the associated emitted powers are calculated using a semi-classical approach. Our results are discussed with respect to distinct ones in the literature, which consider the decay of accelerated protons in electromagnetic fields. A number of consistency checks are presented along the paper.Comment: To appear in Physical Review

The ννγ\nu \nu \gamma Amplitude in an External Homogeneous Electromagnetic Field

Neutrino-photon interactions in the presence of an external homogeneous constant electromagnetic field are studied. The $\nu \nu \gamma$ amplitude is calculated in an electromagnetic field of the general type, when the two field invariants are nonzero.Comment: 7 pages, 1 figur

POLYPOID CYSTITIS: A FINDING AND DIFFERENTIAL DIAGNOSIS

Background. Polypoid cystitis may simulate urothelial neoplasias cystoscopically and histologically. The frequency of polypoid cystitis is 0.38%; that among patients undergoing bladder catheterization is 6 %.Subjects and methods. The authors estimated the frequency of polypoid cystitis among chronic cystitis patients admitted to City Clinical Hospital Fifty, a base of the Clinic of Urology, Moscow State University of Medicine and Dentistry, in the period from February 2008 to February 2010. Out of 819 patients followed up, 3 who had diagnosed as having polypoid cystitis complained of pollakiuria, imperative micturate urges, and macrohematuria. They underwent ultrasonography, computed tomography, and cystoscopy; bladder masses measured 1.0, 7.0, and 11.5 cm, respectively; extensive growth was verified in 2 cases. Endoscopic studies identified procumbent rough-villous masses without well-defined outlines with the signs of bullous edema, decay, hemorrhages, and urinary salt encrustations. By taking into account the clinical picture and laboratory and instrumental findings, the authors suspected stage T3bNхMх bladder tumor in 2 patients and T1NхMх stage in 1. According to the European Association of Urology guidelines for management of bladder cancer, the patients underwent transurethral bladder resection. The patients were diagnosed as having polypoid cystitis on the basis of postmortem evidence.Results. In this study the frequency of polypoid cystitis was 37 %. Polypoid cystitis, a benign mass without a risk for malignancy, had signs of invasive transitional cell carcinoma.Conclusion. Such cases that rarely occur in practice are of clinical value and interest to urologists, pathologists, and oncologists.</p

Lower Bound on the Magnetic Field Strength of a Magnetar from Analysis of SGR Giant Flares

Based on the magnetar model, we have studied in detail the processes of neutrino cooling of an electron--positron plasma generating an SGR giant flare and the influence of the magnetar magnetic field on these processes. Electron--positron pair annihilation and synchrotron neutrino emission are shown to make a dominant contribution to the neutrino emissivity of such a plasma. We have calculated the neutrino energy losses from a plasma-filled region at the long tail stage of the SGR 0526--66, SGR 1806--20, and SGR 1900+14 giant flares. This plasma can emit the energy observed in an SGR giant flare only in the presence of a strong magnetic field suppressing its neutrino energy losses. We have obtained a lower bound on the magnetic field strength and showed this value to be higher than the upper limit following from an estimate of the magnetic dipole losses for the magnetars being analyzed in a wide range of magnetar model parameters. Thus, it is problematic to explain the observed energy release at the long tail stage of an SGR giant flare in terms of the magnetar model.Comment: 18 pages, 5 figure

ПОЛИПОИДНЫЙ ЦИСТИТ: НАХОДКА И ДИФФЕРЕНЦИАЛЬНЫЙ ДИАГНОЗ

Background. Polypoid cystitis may simulate urothelial neoplasias cystoscopically and histologically. The frequency of polypoid cystitis is 0.38%; that among patients undergoing bladder catheterization is 6 %.Subjects and methods. The authors estimated the frequency of polypoid cystitis among chronic cystitis patients admitted to City Clinical Hospital Fifty, a base of the Clinic of Urology, Moscow State University of Medicine and Dentistry, in the period from February 2008 to February 2010. Out of 819 patients followed up, 3 who had diagnosed as having polypoid cystitis complained of pollakiuria, imperative micturate urges, and macrohematuria. They underwent ultrasonography, computed tomography, and cystoscopy; bladder masses measured 1.0, 7.0, and 11.5 cm, respectively; extensive growth was verified in 2 cases. Endoscopic studies identified procumbent rough-villous masses without well-defined outlines with the signs of bullous edema, decay, hemorrhages, and urinary salt encrustations. By taking into account the clinical picture and laboratory and instrumental findings, the authors suspected stage T3bNхMх bladder tumor in 2 patients and T1NхMх stage in 1. According to the European Association of Urology guidelines for management of bladder cancer, the patients underwent transurethral bladder resection. The patients were diagnosed as having polypoid cystitis on the basis of postmortem evidence.Results. In this study the frequency of polypoid cystitis was 37 %. Polypoid cystitis, a benign mass without a risk for malignancy, had signs of invasive transitional cell carcinoma.Conclusion. Such cases that rarely occur in practice are of clinical value and interest to urologists, pathologists, and oncologists.Введение. Полипоидный цистит цистоскопически и гистологически может «симулировать» уротелиальные неоплазии. Частота встречаемости полипоидного цистита составляет 0,38 %; среди пациентов, перенесших катетеризацию мочевого пузыря (МП), – 6 %.Материалы и методы. Мы оценили частоту встречаемости полипоидного цистита среди пациентов с хроническим циститом, поступивших в клинику урологии МГМСУ на базе ГКБ № 50 за период с февраля 2008 по февраль 2010 г. Из наблюдавшихся 819 пациентов 3 больных с диагностированным полипоидным циститом предъявляли жалобы на учащенное мочеиспускание, императивные позывы и макрогематурию. Им были проведены ультразвуковое исследование, компьютерная томография и цистоскопия, размеры образования МП составили 1,0; 7,0 и 11,5 см соответственно, в 2 случаях подтвержден распространенный характер роста. При эндоскопическом исследовании определялись стелющиеся грубоворсинчатые образования без четких границ с явлениями буллезного отека, распада, кровоизлияний и инкрустацией мочевыми солями. С учетом клинической картины и данных лабораторно-инструментальных исследований у 2 пациентов предположили наличие опухоли МП стадии T3bNхMх, у 1 – стадии T1NхMх. Согласно рекомендациям руководства Европейской ассоциации урологов по лечению рака МП пациентам была выполнена трансуретральная резекция МП. На основании данных патоморфологического исследования у пациентов диагностирован полипоидный цистит.Результаты. Частота встречаемости полипоидного цистита в нашем исследовании составила 37 %. Полипоидный цистит, доброкачественное образование без риска развития злокачественного процесса, имел признаки инвазивного переходно-клеточного рака.Заключение. Подобные случаи, редко встречающиеся в практике, представляют клиническую ценность и интересны для урологов, патологов и онкологов

Use of Genomic DNA as an Indirect Reference for Identifying Gender-Associated Transcripts in Morphologically Identical, but Chromosomally Distinct, Schistosoma mansoni Cercariae

BACKGROUND: The use of DNA microarray technology to study global Schistosoma gene expression has led to the rapid identification of novel biological processes, pathways or associations. Implementation of standardized DNA microarray protocols across laboratories would assist maximal interpretation of generated datasets and extend productive application of this technology. METHODOLOGY/PRINCIPAL FINDINGS: Utilizing a new Schistosoma mansoni oligonucleotide DNA microarray composed of 37,632 elements, we show that schistosome genomic DNA (gDNA) hybridizes with less variation compared to complex mixed pools of S. mansoni cDNA material (R = 0.993 for gDNA compared to R = 0.956 for cDNA during ‘self versus self’ hybridizations). Furthermore, these effects are species-specific, with S. japonicum or Mus musculus gDNA failing to bind significantly to S. mansoni oligonucleotide DNA microarrays (e.g R = 0.350 when S. mansoni gDNA is co-hybridized with S. japonicum gDNA). Increased median fluorescent intensities (209.9) were also observed for DNA microarray elements hybridized with S. mansoni gDNA compared to complex mixed pools of S. mansoni cDNA (112.2). Exploiting these valuable characteristics, S. mansoni gDNA was used in two-channel DNA microarray hybridization experiments as a common reference for indirect identification of gender-associated transcripts in cercariae, a schistosome life-stage in which there is no overt sexual dimorphism. This led to the identification of 2,648 gender-associated transcripts. When compared to the 780 gender-associated transcripts identified by hybridization experiments utilizing a two-channel direct method (co-hybridization of male and female cercariae cDNA), indirect methods using gDNA were far superior in identifying greater quantities of differentially expressed transcripts. Interestingly, both methods identified a concordant subset of 188 male-associated and 156 female-associated cercarial transcripts, respectively. Gene ontology classification of these differentially expressed transcripts revealed a greater diversity of categories in male cercariae. Quantitative real-time PCR analysis confirmed the DNA microarray results and supported the reliability of this platform for identifying gender-associated transcripts. CONCLUSIONS/SIGNIFICANCE: Schistosome gDNA displays characteristics highly suitable for the comparison of two-channel DNA microarray results obtained from experiments conducted independently across laboratories. The schistosome transcripts identified here demonstrate, for the first time, that gender-associated patterns of expression are already well established in the morphologically identical, but chromosomally distinct, cercariae stage

Interchromosomal Duplications on the Bactrocera oleae Y Chromosome Imply a Distinct Evolutionary Origin of the Sex Chromosomes Compared to Drosophila

BACKGROUND: Diptera have an extraordinary variety of sex determination mechanisms, and Drosophila melanogaster is the paradigm for this group. However, the Drosophila sex determination pathway is only partially conserved and the family Tephritidae affords an interesting example. The tephritid Y chromosome is postulated to be necessary to determine male development. Characterization of Y sequences, apart from elucidating the nature of the male determining factor, is also important to understand the evolutionary history of sex chromosomes within the Tephritidae. We studied the Y sequences from the olive fly, Bactrocera oleae. Its Y chromosome is minute and highly heterochromatic, and displays high heteromorphism with the X chromosome. METHODOLOGY/PRINCIPAL FINDINGS: A combined Representational Difference Analysis (RDA) and fluorescence in-situ hybridization (FISH) approach was used to investigate the Y chromosome to derive information on its sequence content. The Y chromosome is strewn with repetitive DNA sequences, the majority of which are also interdispersed in the pericentromeric regions of the autosomes. The Y chromosome appears to have accumulated small and large repetitive interchromosomal duplications. The large interchromosomal duplications harbour an importin-4-like gene fragment. Apart from these importin-4-like sequences, the other Y repetitive sequences are not shared with the X chromosome, suggesting molecular differentiation of these two chromosomes. Moreover, as the identified Y sequences were not detected on the Y chromosomes of closely related tephritids, we can infer divergence in the repetitive nature of their sequence contents. CONCLUSIONS/SIGNIFICANCE: The identification of Y-linked sequences may tell us much about the repetitive nature, the origin and the evolution of Y chromosomes. We hypothesize how these repetitive sequences accumulated and were maintained on the Y chromosome during its evolutionary history. Our data reinforce the idea that the sex chromosomes of the Tephritidae may have distinct evolutionary origins with respect to those of the Drosophilidae and other Dipteran families