2,257 research outputs found

    Cancer is a side effect of evolution of viruses and bacteria

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    Any human organism is home to viruses and bacteria. However, viruses (as well as other intracellular parasites) are interested in continuous division of the host cells. Unlimited division of the host cells means unlimited expansion of the living space and possibility for unlimited multiplication of viral particles. For this, human Cell Cycle Regulation System has to be affected in such a way to induce unlimited division of host cells. The present work describes oncogenome`s model of cancer development, according to which, in order to stimulate cell division, viruses affect a gene (or several genes) during transduction of a signal for cell division from growth factor to cyclin/CDK system. At the same time, controlling gene (p53, RB etc.) function and a switch to apoptosis are suppressed. Cell switch to cell division implies inability of the cell to carry out the functions of a differentiated cell. Spreading of viruses (bacteria) to the adjacent cells and forcing them into division, with simultaneous loss of differentiated cell functions, will become evident as the formation of malignant tumor or cancer

    Comment on "Giant Nernst Effect due to Fluctuating Cooper Pairs in Superconductors" by M.N. Serbyn, M.A. Skvortsov, A.A. Varlamov, and V. Galitski

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    In a recent Letter, Serbyn et al. [A] investigated thermomagnetic effects above the superconducting transition and generalized previous works for arbitrary magnetic fields and temperatures. While the results of [A] have been confirmed in [B], we have strong objections: (i) According to our results [C], the linear response calculation does not require any correction from the magnetization currents; (ii) The result of [A,B] is giant, because unlike the normal Fermi liquid, it is of zero order in the particle-hole asymmetry. Changing the interaction constant in the Cooper channel leads to ridiculously large results even for nonsuperconducting metals; (iii)Derived in [A] the Einstein-type relation for thermomagnetic coefficient contradicts to text-book results. [A] M.N. Serbyn, M.A. Skvortsov, A.A. Varlamov, V. Galitski, Phys. Rev. Lett. 102, 067001 (2009). [B] K. Michaeli and A.M. Finkel'stein, EPL 86, 27007 (2009). [C] A. Sergeev et al., Phys. Rev. B 77, 064501 (2008)

    Diffusion of photoexcited carriers in graphene

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    The diffusion of electron-hole pairs, which are excited in an intrinsic graphene by the ultrashort focused laser pulse in mid-IR or visible spectral region, is described for the cases of peak-like or spread over the passive region distributions of carriers. The spatio-temporal transient optical response on a high-frequency probe beam appears to be strongly dependent on the regime of diffusion and can be used for verification of the elasic relaxation mechanism. Sign flip of the differential transmission coefficient takes place due to interplay of the carrier-induced contribution and weak dynamic conductivity of undoped graphene.Comment: 4 pages, 4 figure

    Microwave-induced resistance oscillations and zero-resistance states in 2D electron systems with two occupied subbands

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    We report on theoretical studies of recently discovered microwave-induced resistance oscillations and zero resistance states in Hall bars with two occupied subbands. In the same results, resistance presents a peculiar shape which appears to have a built-in interference effect not observed before. We apply the microwave-driven electron orbit model, which implies a radiation-driven oscillation of the two-dimensional electron system. Thus, we calculate different intra and inter-subband electron scattering rates and times that are revealing as different microwave-driven oscillations frequencies for the two electronic subbands. Through scattering, these subband-dependent oscillation motions interfere giving rise to a striking resistance profile. We also study the dependence of irradiated magnetoresistance with power and temperature. Calculated results are in good agreement with experiments.Comment: 7 pages, 6 figure

    Is moderate hypofractionation accepted as a new standard of care in north america for prostate cancer patients treated with external beam radiotherapy? Survey of genitourinary expert radiation oncologists

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    INTRODUCTION: Several recent randomized clinical trials have evaluated hypofractionated regimens against conventionally fractionated EBRT and shown similar effectiveness with conflicting toxicity results. The current view regarding hypofractionation compared to conventional EBRT among North American genitourinary experts for management of prostate cancer has not been investigated. MATERIALS AND METHODS: A survey was distributed to 88 practicing North American GU physicians serving on decision - making committees of cooperative group research organizations. Questions pertained to opinions regarding the default EBRT dose and fractionation for a hypothetical example of a favorable intermediate - risk prostate cancer (Gleason 3 + 4). Treatment recommendations were correlated with practice patterns using Fisher's exact test. RESULTS: Forty - two respondents (48%) completed the survey. We excluded from analysis two respondents who selected radical hypofractionation with 5 - 12 fractions as a preferred treatment modality. Among the 40 analyzed respondents, 23 (57.5%) recommend conventional fractionation and 17 (42.5%) recommended moderate hypofractionation. No demographic factors were found to be associated with preference for a fractionation regimen. Support for brachytherapy as a first choice treatment modality for low - risk prostate cancer was borderline significantly associated with support for moderate hypofractionated EBRT treatment modality (p = 0.089). CONCLUSIONS: There is an almost equal split among North American GU expert radiation oncologists regarding the appropriateness to consider moderately hypofractionated EBRT as a new standard of care in management of patients with prostate cancer. Physicians who embrace brachytherapy may be more inclined to support moderate hypofractionated regimen for EBRT. It is unclear whether reports with longer followups will impact this balance, or whether national care and reimbursement policies will drive the clinical decisions. In the day and age of patient - centered care delivery, patients should receive an objective recommendation based on available clinical evidence. The stark division among GU experts may influence the design of future clinical trials utilizing EBRT for patients with prostate cancer
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