165 research outputs found

    Effect of Age at Diagnosis on Cervical Cancer Patient Prognoses in Georgia

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    The current incidence of cervical cancer varies around 17.0/100,000 women per year. The study aims to describe the effect of age at diagnosis on CC patient prognosis in Georgia. Methods. Univariable and Multivariable survival analysis using Cox’s regression model was constructed. All women aged ≤80 years,  diagnosed with invasive CC (ICD10-site code C53) from 2015 to 2019,  were eligible for inclusion in the analysis. During analysis a hazard (mortality) ratio for the patients, who were diagnosed at different ages was estimated. Survival period was determined from the date of diagnosis until the date of death or the date of last follow up visit. High risk of death was defined as a mortality of CC patients whose survival period was less than 5 years.The level of statistical significance of the study findings is estimated by using p-value andthe 95% of confidence interval (95%CI). A p value < 0.05 was considered as statistically significant. In estimation of hazard ratio, the patients under 41 years were selected as a reference group. Data was analyzed using Statistical Package of SPSS version 23. Results.Totally 1646 CC patients were enrolled in the study. The median age at diagnosis was 54years and age range was 25 - 80 years. Univariable statistical analysis has revealed that cancer diagnosed over 60 years of age had a higher death hazard (HR=1.80, p<0.001), compared to cancer detected under 60 years (HR=3.30, p<0.001). Multivariable statistical analysis has detected that stage and age at diagnosis are independent, statistically significant predictors for high mortality in patients diagnosed with cervical cancer, while the role of histological grade has not been revealed. In addition, older age generally is related to a high prevalence of comorbidities. The reasons for the unfavourable cervical cancer prognosis in older patients that was detected  during statistical analysis might be explained by tumor stage at diagnoses and with higher ratesof comorbidity among the elderly. Conclusions: Finally, our study results are in concordance with numerous studies, which confirm that the age of patients at the moment of diagnosis is an independent predictor for cervical cancer early mortality

    Two-step interphase microtubule disassembly aids spindle morphogenesis

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    Background Entry into mitosis triggers profound changes in cell shape and cytoskeletal organisation. Here, by studying microtubule remodelling in human flat mitotic cells, we identify a two-step process of interphase microtubule disassembly. Results First, a microtubule-stabilising protein, Ensconsin/MAP7, is inactivated in prophase as a consequence of its phosphorylation downstream of Cdk1/cyclin B. This leads to a reduction in interphase microtubule stability that may help to fuel the growth of centrosomally nucleated microtubules. The peripheral interphase microtubules that remain are then rapidly lost as the concentration of tubulin heterodimers falls following dissolution of the nuclear compartment boundary. Finally, we show that a failure to destabilise microtubules in prophase leads to the formation of microtubule clumps, which interfere with spindle assembly. Conclusions This analysis highlights the importance of the step-wise remodelling of the microtubule cytoskeleton and the significance of permeabilisation of the nuclear envelope in coordinating the changes in cellular organisation and biochemistry that accompany mitotic entry

    Chaotic Phenomenon in Nonlinear Gyrotropic Medium

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    Nonlinear gyrotropic medium is a medium, whose natural optical activity depends on the intensity of the incident light wave. The Kuhn's model is used to study nonlinear gyrotropic medium with great success. The Kuhn's model presents itself a model of nonlinear coupled oscillators. This article is devoted to the study of the Kuhn's nonlinear model. In the first paragraph of the paper we study classical dynamics in case of weak as well as strong nonlinearity. In case of week nonlinearity we have obtained the analytical solutions, which are in good agreement with the numerical solutions. In case of strong nonlinearity we have determined the values of those parameters for which chaos is formed in the system under study. The second paragraph of the paper refers to the question of the Kuhn's model integrability. It is shown, that at the certain values of the interaction potential this model is exactly integrable and under certain conditions it is reduced to so-called universal Hamiltonian. The third paragraph of the paper is devoted to quantum-mechanical consideration. It shows the possibility of stochastic absorption of external field energy by nonlinear gyrotropic medium. The last forth paragraph of the paper is devoted to generalization of the Kuhn's model for infinite chain of interacting oscillators

    Nonlinear dynamics of two coupled nano-electromechanical resonators

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    As a model of coupled nano-electromechanical resonantors we study two nonlinear driven oscillators with an arbitrary coupling strength between them. Analytical expressions are derived for the oscillation amplitudes as a function of the driving frequency and for the energy transfer rate between the two oscillators. The nonlinear restoring forces induce the expected nonlinear resonance structures in the amplitude-frequency characteristics with asymmetric resonance peaks. The corresponding multistable behavior is shown to be an efficient tool to control the energy transfer arising from the sensitive response to small changes in the driving frequency. Our results imply that the nonlinear response can be exploited to design precise sensors for mass or force detection experiments based on nano-electromechanical resonators.Comment: 19 pages, 2 figure

    POLAR, an instrument to measure GRB polarization. Design and laboratory tests.

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    International audienceReliable polarization measurements of photons from Gamma Ray Bursts (GRB) would make the understanding of the GRB phenomenon progress enormously. POLAR is a concept for an instrument that would enable such a measurement. We report about performances predicted by of Monte-Carlo and on laboratory tests to validate some critical aspects of the desig

    Measurement of the analyzing powers in pd elastic and pn quasi-elastic scattering at small angles

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    The analyzing powers in proton-deuteron elastic and proton-neutron quasi-elastic scattering have been measured at small angles using a polarized proton beam at the COSY storage ring incident on an unpolarized deuterium target. The data were taken at 796MeV and five higher energies from 1600MeV to 2400MeV. The analyzing power in pd elastic scattering was studied by detecting the low energy recoil deuteron in telescopes placed symmetrically in the COSY plane to the left and right of the beam whereas for pn quasi-elastic scattering a low energy proton was registered in one of the telescopes in coincidence with a fast scattered proton measured in the ANKE magnetic spectrometer. Though the experiment explores new domains, the results are consistent with the limited published information.Comment: 10 pages with 8 figure

    POLAR: a compact detector for GRB polarization measurements

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    Présenté par J.P. VialleInternational audienceThrough polarization measurements of X-rays can provide essential information for identifying processes responsible of their emission by astrophysical objects, almost no experimental data exist yet. We propose here a novel wide field compact detector for hard X-ray polarization measurements based on Compton scattering process and made of low-Z fast scintillators

    First measurements of spin correlations in the np -> d pi^0 reaction

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    The transverse spin correlations Axx and Ayy in the np-> d pi^0 reaction have been measured for the first time in quasi-free kinematics at the COSY-ANKE facility using a polarised deuteron beam incident on a polarised hydrogen cell target. The results obtained for neutron energies close to 353 MeV and 600 MeV are in good agreement with the partial wave analysis of data on the isospin-related pp-> d pi^+ reaction, though the present results cover also the small-angle region, which was largely absent from these data

    Coherent pion production in proton-deuteron collisions

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    Values of the proton analysing power in the pd3Heπ0/3Hπ+pd\to{}^{3}\textrm{He}\,\pi^0/^{3}\textrm{H}\,\pi^+ reactions at 350-360~MeV per nucleon were obtained by using a polarised proton beam incident on a deuterium cluster-jet target and with a polarised deuteron beam incident on a target cell filled with polarised hydrogen. These results have a much larger angular coverage than existing data. First measurements are also presented of the deuteron vector analysing power and the deuteron-proton spin correlations. Data were also obtained on the deuteron-proton spin correlation and proton analysing power at small angles at 600~MeV per nucleon, though the angular coverage at this energy was much more restricted even when using a deuteron beam. By combining the extrapolated values of the spin correlations to the forward or backward directions with published measurements of the deuteron tensor analysing powers, the relative phases between the two non-vanishing amplitudes were evaluated.Comment: 5 pages, 5 figure

    Myo19 ensures symmetric partitioning of mitochondria and coupling of mitochondrial segregation to cell division.

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    During animal cell division, an actin-based ring cleaves the cell into two. Problems with this process can cause chromosome missegregation and defects in cytoplasmic inheritance and the partitioning of organelles, which in turn are associated with human diseases. Although much is known about how chromosome segregation is coupled to cell division, the way organelles coordinate their inheritance during partitioning to daughter cells is less well understood. Here, using a high-content live-imaging small interfering RNA screen, we identify Myosin-XIX (Myo19) as a novel regulator of cell division. Previously, this actin-based motor was shown to control the interphase movement of mitochondria. Our analysis shows that Myo19 is indeed localized to mitochondria and that its silencing leads to defects in the distribution of mitochondria within cells and in mitochondrial partitioning at division. Furthermore, many Myo19 RNAi cells undergo stochastic division failure--a phenotype that can be mimicked using a treatment that blocks mitochondrial fission and rescued by decreasing mitochondrial fusion, implying that mitochondria can physically interfere with cytokinesis. Strikingly, using live imaging we also observe the inappropriate movement of mitochondria to the poles of spindles in cells depleted for Myo19 as they enter anaphase. Since this phenocopies the results of an acute loss of actin filaments in anaphase, these data support a model whereby the Myo19 actin-based motor helps to control mitochondrial movement to ensure their faithful segregation during division. The presence of DNA within mitochondria makes their inheritance an especially important aspect of symmetrical cell division
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