174 research outputs found

    Sp1 acetylation is associated with loss of DNA binding at promoters associated with cell cycle arrest and cell death in a colon cell line

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    Butyrate, a known histone deacetylase inhibitor (HDACi) and product of fibre fermentation, is postulated to mediate the protective effect of dietary fibre against colon cancer. The transcription factor Sp1 is a target of acetylation and is known to be associated with class I HDACs, including HDAC1. Sp1 is a ubiquitous transcription factor and Sp1-regulated genes include those involved in cell cycle regulation, apoptosis and lipogenesis: all major pathways in cancer development. The only known acetylated residue of Sp1 is lysine703 which resides in the DNA binding domain. Here we show that acetylated Sp1 loses p21- and bak-promoter -binding function in vitro. Furthermore treatment with a panel of HDAC inhibitors showed clustering of activities for a subset of inhibitors, causing G2 cell cycle arrest, Sp1 acetylation, p21 and Bak over-expression, all with very similar EC50 concentrations. These HDACi activities were not distributed according to the molecular class of compound. In order to mimic loss of binding, an siRNA strategy was used to reduce Sp1 expression. This resulted in altered expression of multiple elements of the p53/p21 pathway. Taken together our data suggest a mechanistic model for the chemopreventive actions of butyrate in colon epithelial cells, and provide new insight into the differential activities some classes of HDAC inhibitors

    Possibility of Using a Satellite-Based Detector for Recording Cherenkov Light from Ultrahigh-Energy Extensive Air Showers Penetrating into the Ocean Water

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    We have estimated the reflected component of Cherenkov radiation, which arises in developing of an extensive air shower with primary energy of 10^20 eV over the ocean surface. It has been shown that, under conditions of the TUS experiment, a flash of the reflected Cherenkov photons at the end of the fluorescence track can be identified in showers with zenith angles up to 20 degrees.Comment: 5 pages, 3 figures. This preprint corrects errors which appeared in the English version of the article published in Bull. Rus. Acad. Sci. Phys., 2011, Vol. 75, No. 3, p. 381. The original russian text was published in Izv. RAN. Ser. Fiz., 2011, Vol. 75, No. 3, p. 41

    On the effects of using CO2 and F2 lasers to modify the wettability of a polymeric biomaterial.

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    Enhancement of the surface properties of a material by means of laser radiation has been amply demonstrated previously. In this work a comparative study for the surface modification of nylon 6,6 has been conducted in order to vary the wettability characteristics using CO2 and excimer lasers. This was done by producing 50 μm spaced (with depths between 1 and 10 μm) trench-like patterns using various laser parameters such as varying the laser power for the CO2 laser and number of pulses for the excimer laser. Topographical changes were analysed using optical microscopy and white light interferometry which indicated that both laser systems can be implemented for modifying the topography of nylon 6,6. Variations in the surface chemistry were evaluated using energy-dispersive X-ray spectroscopy and x-ray photoelectron spectroscopy analysis and showed that the O2 increased by up to 1.5% At. and decreased by up to 1.6% At. for the CO2 and F2 laser patterned samples, respectively. Modification of the wettability characteristics was quantified by measuring the advancing contact angle, which was found to increase in all instances for both laser systems. Emery paper roughened samples were also analysed in the same manner to determine that the topographical pattern played a major role in the wettability characteristics of nylon 6,6. From this, it is proposed that the increase in contact angle for the laser processed samples is due to a mixed intermediate state wetting regime owed to the periodic surface roughness brought about by the laser induced trench-like topographical patterns

    Determining small refractive index contrast in chalcogenide-glass pairs at mid-infrared wavelengths

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    A two-composition thin film (Ge20Sb10Se70/Ge20Sb10Se67S3 atomic%core/cladding glasses) was fabricated using a hot-fibre-pressing technique in which both glasses follow the same post-fibre processing. A simple approach is proposed that uses normal incidence transmission spectra to determine their refractive index contrast over the wavelength range from 2 to 25 μm with an error of less than _ 0.002. Using an improved Swanepoel method, the calculated numerical aperture of these two compositions was within _ 0.011 of that obtained from prism minimum deviation measurements. Results show that introducing 3 atomic % S into the Ge-Sb-Se glass system lowered the refractive index and blue-shifted the visible optical bandgap, the far-infrared fundamental vibrational absorption bands and the zero-dispersion wavelength

    Photonic molecules and spectral engineering

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    This chapter reviews the fundamental optical properties and applications of pho-tonic molecules (PMs) - photonic structures formed by electromagnetic coupling of two or more optical microcavities (photonic atoms). Controllable interaction between light and matter in photonic atoms can be further modified and en-hanced by the manipulation of their mutual coupling. Mechanical and optical tunability of PMs not only adds new functionalities to microcavity-based optical components but also paves the way for their use as testbeds for the exploration of novel physical regimes in atomic physics and quantum optics. Theoretical studies carried on for over a decade yielded novel PM designs that make possible lowering thresholds of semiconductor microlasers, producing directional light emission, achieving optically-induced transparency, and enhancing sensitivity of microcavity-based bio-, stress- and rotation-sensors. Recent advances in material science and nano-fabrication techniques make possible the realization of optimally-tuned PMs for cavity quantum electrodynamic experiments, classical and quantum information processing, and sensing.Comment: A review book chapter: 29 pages, 19 figure

    Projected WIMP sensitivity of the LUX-ZEPLIN dark matter experiment

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    LUX-ZEPLIN (LZ) is a next-generation dark matter direct detection experiment that will operate 4850 feet underground at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. Using a two-phase xenon detector with an active mass of 7 tonnes, LZ will search primarily for low-energy interactions with weakly interacting massive particles (WIMPs), which are hypothesized to make up the dark matter in our galactic halo. In this paper, the projected WIMP sensitivity of LZ is presented based on the latest background estimates and simulations of the detector. For a 1000 live day run using a 5.6-tonne fiducial mass, LZ is projected to exclude at 90% confidence level spin-independent WIMP-nucleon cross sections above 1.4 × 10-48cm2 for a 40 GeV/c2 mass WIMP. Additionally, a 5σ discovery potential is projected, reaching cross sections below the exclusion limits of recent experiments. For spin-dependent WIMP-neutron(-proton) scattering, a sensitivity of 2.3 × 10−43 cm2 (7.1 × 10−42 cm2) for a 40 GeV/c2 mass WIMP is expected. With underground installation well underway, LZ is on track for commissioning at SURF in 2020

    Global, regional, and national incidence, prevalence, and years lived with disability for 328 diseases and injuries for 195 countries, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016

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    As mortality rates decline, life expectancy increases, and populations age, non-fatal outcomes of diseases and injuries are becoming a larger component of the global burden of disease. The Global Burden of Diseases, Injuries, and Risk Factors Study 2016 (GBD 2016) provides a comprehensive assessment of prevalence, incidence, and years lived with disability (YLDs) for 328 causes in 195 countries and territories from 1990 to 2016

    Cultural constructions of happiness: theory and emprical evidence

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    In a review of recent cross-cultural evidence on happiness and well-being, the authors identified substantial cultural variations in (1) cultural meanings of happiness, (2) motivations underlying happiness, and (3) predictors of happiness. Specifically, in North American cultural contexts, happiness tends to be defined in terms of personal achievement. Individuals engaging in these cultures are motivated to maximize the experience of positive affect. Moreover, happiness is best predicted by self-esteem. In contrast, in East Asian cultural contexts, happiness tends to be defined in terms of interpersonal connectedness. Individuals engaging in these cultures are motivated to maintain a balance between positive and negative affects. Moreover, happiness is best predicted by perceived embeddedness of the self in a social relationship. Directions for future research are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43061/1/10902_2004_Article_5278785.pd

    The polarized image of a synchrotron-emitting ring of gas orbiting a black hole

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    High Energy Astrophysic
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