517 research outputs found

    UVB radiation induced effects on cells studied by FTIR spectroscopy

    Full text link
    We have made a preliminary analysis of the results about the eVects on tumoral cell line (lymphoid T cell line Jurkat) induced by UVB radiation (dose of 310 mJ/cm^2) with and without a vegetable mixture. In the present study, we have used two techniques: Fourier transform infrared spectroscopy (FTIR) and flow cytometry. FTIR spectroscopy has the potential to provide the identiWcation of the vibrational modes of some of the major compounds (lipid, proteins and nucleic acids) without being invasive in the biomaterials. The second technique has allowed us to perform measurements of cytotoxicity and to assess the percentage of apoptosis. We already studied the induction of apoptotic process in the same cell line by UVB radiation; in particular, we looked for correspondences and correlations between FTIR spetroscopy and flow cytometry data finding three highly probable spectroscopic markers of apoptosis (Pozzi et al. in Radiat Res 168:698-705, 2007). In the present work, the results have shown significant changes in the absorbance and spectral pattern in the wavenumber protein and nucleic acids regions after the treatments

    The River Gave and the River Hath Taken Away: How the Arkansas River Shaped the Course of Arkansas History

    Get PDF
    The Arkansas River molded the history of Arkansas. It also shaped human to human interactions and human relationships with the physical environment. Since humans first encountered the river their lives have been influenced by it. The river played a significant role in creating the environmental conditions that contributed to a specific existence within the river valley. It affected what types of flora and fauna existed, the quality of the soil, and the climate. The river was a vital component in the evolution of the cultures and societies that developed in the river valley. Conversely, humans affected the river. The ways humans perceived and used the river impacted the physical characteristics that defined the river. Ever since the first humans interacted with the river there has been a dialectic relationship put into motion, a cycle of constant change where humans and the environment renegotiated their understandings and relationship with one another. Throughout every time period of Arkansas history, prehistoric through the 1970s and on, the river has been a vital factor in the existence of the river valley and state

    Обоснование мер обеспечения эффективности деятельности предприятия пищевой промышленности

    Get PDF
    У даній статті розглядається поняття та сутність виробничо-господарської діяльності підприємства та наведено основні заходи підвищення її ефективності для підприємств харчової промисловості.This article discusses the concept and nature of industrial and business enterprises and are the main measures to increase its efficiency for the food industry.В данной статье рассматривается понятие и сущность производственной деятельности предприятия и приведены основные меры повышения ее эффективности для предприятий пищевой промышленности

    Ears of the Armadillo: Global Health Research and Neglected Diseases in Texas

    Get PDF
    Neglected tropical diseases (NTDs) have\ud been recently identified as significant public\ud health problems in Texas and elsewhere in\ud the American South. A one-day forum on the\ud landscape of research and development and\ud the hidden burden of NTDs in Texas\ud explored the next steps to coordinate advocacy,\ud public health, and research into a\ud cogent health policy framework for the\ud American NTDs. It also highlighted how\ud U.S.-funded global health research can serve\ud to combat these health disparities in the\ud United States, in addition to benefiting\ud communities abroad

    The Q^2-Dependence of Nuclear Transparency for Exclusive ρ0\rho^0 Production

    Full text link
    Exclusive coherent and incoherent electroproduction of the ρ0\rho^0 meson from 1^1H and 14^{14}N targets has been studied at the HERMES experiment as a function of coherence length (lcl_c), corresponding to the lifetime of hadronic fluctuations of the virtual photon, and squared four-momentum of the virtual photon (Q2-Q^2). The ratio of 14^{14}N to 1^1H cross sections per nucleon, known as nuclear transparency, was found to increase (decrease) with increasing coherence length for coherent (incoherent) ρ0\rho^0 electroproduction. For fixed coherence length, a rise of nuclear transparency with Q2Q^2 is observed for both coherent and incoherent ρ0\rho^0 production, which is in agreement with theoretical calculations of color transparency.Comment: 5 pages, 4 figure

    Nuclear Polarization of Molecular Hydrogen Recombined on a Non-metallic Surface

    Full text link
    The nuclear polarization of H2\mathrm{H}_2 molecules formed by recombination of nuclear polarized H atoms on the surface of a storage cell initially coated with a silicon-based polymer has been measured by using the longitudinal double-spin asymmetry in deep-inelastic positron-proton scattering. The molecules are found to have a substantial nuclear polarization, which is evidence that initially polarized atoms retain their nuclear polarization when absorbed on this type of surfac

    Double hadron leptoproduction in the nuclear medium

    Full text link
    First measurement of double-hadron production in deep-inelastic scattering has been measured with the HERMES spectrometer at HERA using a 27.6 GeV positron beam with deuterium, nitrogen, krypton and xenon targets. The influence of the nuclear medium on the ratio of double-hadron to single-hadron yields has been investigated. Nuclear effects are clearly observed but with substantially smaller magnitude and reduced AA-dependence compared to previously measured single-hadron multiplicity ratios. The data are in fair agreement with models based on partonic or pre-hadronic energy loss, while they seem to rule out a pure absorptive treatment of the final state interactions. Thus, the double-hadron ratio provides an additional tool for studying modifications of hadronization in nuclear matter

    Single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target

    Full text link
    Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering of positrons are measured for the first time with transverse target polarization. The asymmetry depends on the azimuthal angles of both the pion (ϕ\phi) and the target spin axis (ϕS\phi_S) about the virtual photon direction and relative to the lepton scattering plane. The extracted Fourier component \cmpi is a signal of the previously unmeasured quark transversity distribution, in conjunction with the so-called Collins fragmentation function, also unknown. The Fourier component \smpi of the asymmetry arises from a correlation between the transverse polarization of the target nucleon and the intrinsic transverse momentum of quarks, as represented by the previously unmeasured Sivers distribution function. Evidence for both signals is observed, but the Sivers asymmetry may be affected by exclusive vector meson productio

    Subleading-twist effects in single-spin asymmetries in semi-inclusive deep-inelastic scattering on a longitudinally polarized hydrogen target

    Get PDF
    Single-spin asymmetries in the semi-inclusive production of charged pions in deep-inelastic scattering from transversely and longitudinally polarized proton targets are combined to evaluate the subleading-twist contribution to the longitudinal case. This contribution is significantly positive for (\pi^+) mesons and dominates the asymmetries on a longitudinally polarized target previously measured by \hermes. The subleading-twist contribution for (\pi^-) mesons is found to be small
    corecore