440 research outputs found

    Terahertz lasers based on intracentre transitions of group V donors in uniaxially deformed silicon

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    This paper presents a brief overview of available experimental data on the characteristics of stimulated terahertz emission (4.9 – 6.4 THz) from optically excited neutral group V donors (phosphorus, antimony, arsenic and bismuth) in crystalline silicon subjected to uniaxial compressive strain along the [100] axis. Strain is shown to have a significant effect on the characteristics in question. Optimal strain depends on the dopant and may reduce the threshold pump intensity and improve lasing efficiency. We discuss possible mechanisms behind this effect and estimate the limiting output emission parameters

    Случай онихоматрикомы у женщины 53 лет

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    This paper presents a case of onyсhomatricoma — a rare tumour of the nail matrix — in a 53-year-old woman.В статье представлено наблюдение случая редкой опухоли ногтевого матрикса — онихоматрикомы — у женщины 53 лет

    A multiwavelength study of the supernova remnant G296.8-0.3

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    We report XMM-Newton observations of the Galactic supernova remnant G296.8-0.3, together with complementary radio and infrared data. The spatial and spectral properties of the X-ray emission, detected towards G296.8-0.3, was investigated in order to explore the possible evolutionary scenarios and the physical connexion with its unusual morphology detected at radio frequencies. G296.8-0.3 displays diffuse X-ray emission correlated with the peculiar radio morphology detected in the interior of the remnant and with the shell-like radio structure observed to the northwest side of the object. The X-ray emission peaks in the soft/medium energy range (0.5-3.0 keV). The X-ray spectral analysis confirms that the column density is high (NH \sim 0.64 x 10^{22} cm^{-2}) which supports a distant location (d>9 kpc) for the SNR. Its X-ray spectrum can be well represented by a thermal (PSHOCK) model, with kT \sim 0.86 keV, an ionization timescale of 6.1 x 10^{10} cm^{-3} s, and low abundance (0.12 Z_sun). The 24 microns observations show shell-like emission correlated with part of the northwest and southeast boundaries of the SNR. In addition a point-like X-ray source is also detected close to the geometrical center of the radio SNR. The object presents some characteristics of the so-called compact central objects (CCO). Its X-ray spectrum is consistent with those found at other CCOs and the value of NH is consistent with that of G296.8-0.3, which suggests a physical connexion with the SNR.Comment: Accepted for publication in Astrophysics & Space Scienc

    РАЗРАБОТКА ДИАГНОСТИЧЕСКОЙ ТЕСТ-СИСТЕМЫ ДЛЯ РАННЕЙ НЕИНВАЗИВНОЙ ДИАГНОСТИКИ РАКА ПРОСТАТЫ, ОСНОВАННОЙ НА КОЛИЧЕСТВЕННОЙ ДЕТЕКЦИИ МРНК ГЕНА PCA3 В ОСАДКЕ МОЧИ МЕТОДОМ ОТ-ПЦР В РЕЖИМЕ РЕАЛЬНОГО ВРЕМЕНИ

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    The wide introduction of prostatic specific antigen (PSA) determination into clinical practice has resulted in a larger number of prostate biopsies, while the lower age threshold for PSA has led to a larger number of unnecessary prostate biopsies. Hence, there is a need for new biomarkers that can detect prostate cancer. РCА3 is a noncoding messenger ribonucleic acid (mRNA) that is expressed exclusively in prostate cells.  The aim of the study  has been to develop a diagnostic test system for early non-invasive detection of prostate cancer based on PCA3 mRNA levels in urine sediment using quantitative reverse transcription polymerase chain reaction (qRT-PCR). As part of the study, a laboratory diagnostic test system prototype has been designed, an application methodology has been developed and specificity and sensitivity data of the method has been assessed. The diagnostic system has demonstrated its ability to detect significantly elevated levels of PCA 3/ KLK 3 in samples from prostate cancer (PCa) patients compared with those from healthy men. The findings have shown relatively high diagnostic sensitivity, specificity and negative-predictive values for an early non-invasive screening of prostate cancerШирокое внедрение в клиническую практику определения содержания простатического специфического антигена (ПСА) привело к увеличению числа выполняемых биопсий простаты, а снижение порога возрастных норм ПСА — к увеличению числа неоправданных биопсий. В связи с этим возникла необходимость в новых биомаркерах рака предстательной железы. РСА3 — некодирующая мРНК, которая экспрессируется исключительно клетками предстательной железы. Целью данной работы было разработать диагностическую тест-систему для ранней неинвазивной диагностики рака простаты, основанной на количественной детекции мРНК гена РСА3 в осадке мочи методом полимеразной цепной реакции (ПЦР) в режиме реального времени сопряженной с обратной транскрипцией (ОТ). В результате был создан лабораторный образец диагностической ПЦР-тест-системы и отработана методика его применения. Получены данные о специфичности и чувствительности разработанного метода. Показана способность диагностической системы выявлять значительное превышение параметра PCA3/KLK3 в образцах биоматериала, полученного от больных раком простаты, по сравнению с образцами от здоровых индивидуумов. В ходе проведенных исследований установлены достаточно высокие показатели диагностической чувствительности, специфичности и негативной предсказательной ценности для раннего неинвазивного скринингово обнаружения рака предстательной железы. 

    Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

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    Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

    Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

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    A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters

    Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV

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    The Lambda(b) differential production cross section and the cross section ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7 TeV using data collected by the CMS experiment at the LHC. The measurements are based on Lambda(b) decays reconstructed in the exclusive final state J/Psi Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and Lambda to proton pion, using a data sample corresponding to an integrated luminosity of 1.9 inverse femtobarns. The product of the cross section times the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls faster than that of b mesons. The measured value of the cross section times the branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06 +/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are statistical and systematic, respectively.Comment: Submitted to Physics Letters
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