705 research outputs found

    Combinations of antioxidants and/or of epigenetic enzyme inhibitors allow for enhanced collection of mouse bone marrow hematopoietic stem cells in ambient air

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    Hematopoietic cell transplantation (HCT) is a treatment for malignant and non-malignant disorders. However, sometimes the numbers of donor hematopoietic stem cells (HSC) are limiting, which can compromise the success of HCT. We recently published that collection and processing of mouse bone marrow (BM) and human cord blood cells in a hypoxic atmosphere of 3% O2 or in ambient air (~21% O2) in the presence of cyclosporine A yields increased numbers of HSC. We now show that collection and processing of mouse BM cells in ambient air in the presence of specific combinations of anti-oxidants and/or inhibitors of epigenetic enzymes can also enhance the collection of HSC, information of potential relevance for enhanced efficacy of HCT

    Cigarette Smoking, Birthweight and Osteoporosis in Adulthood: Results from the Hertfordshire Cohort Study

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    We looked for interaction between early environment and adult lifestyle in determination of bone mineral content (BMC) and bone mineral density (BMD) among 498 men and 468 women for whom birth records were available. Participants completed a health questionnaire, and bone densitometry (DXA) of the lumbar spine and femoral neck performed

    A self-consistent treatment of non-equilibrium spin torques in magnetic multilayers

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    It is known that the transfer of spin angular momenta between current carriers and local moments occurs near the interface of magnetic layers when their moments are non-collinear. However, to determine the magnitude of the transfer, one should calculate the spin transport properties far beyond the interface regions. Based on the spin diffusion equation, we present a self-consistent approach to evaluate the spin torque for a number of layered structures. One of the salient features is that the longitudinal and transverse components of spin accumulations are inter-twined from one layer to the next, and thus, the spin torque could be significantly amplified with respect to treatments which concentrate solely on the transport at the interface due to the presence of the much longer longitudinal spin diffusion length. We conclude that bare spin currents do not properly estimate the spin angular momentum transferred between to the magnetic background; the spin transfer that occurs at interfaces should be self-consistently determined by embedding it in our globally diffuse transport calculations.Comment: 21 pages, 6 figure

    Bessel Process and Conformal Quantum Mechanics

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    Different aspects of the connection between the Bessel process and the conformal quantum mechanics (CQM) are discussed. The meaning of the possible generalizations of both models is investigated with respect to the other model, including self adjoint extension of the CQM. Some other generalizations such as the Bessel process in the wide sense and radial Ornstein- Uhlenbeck process are discussed with respect to the underlying conformal group structure.Comment: 28 Page

    Correlation Entropy of an Interacting Quantum Field and H-theorem for the O(N) Model

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    Following the paradigm of Boltzmann-BBGKY we propose a correlation entropy (of the nth order) for an interacting quantum field, obtained by `slaving' (truncation with causal factorization) of the higher (n+1 th) order correlation functions in the Schwinger-Dyson system of equations. This renders an otherwise closed system effectively open where dissipation arises. The concept of correlation entropy is useful for addressing issues related to thermalization. As a small yet important step in that direction we prove an H-theorem for the correlation entropy of a quantum mechanical O(N) model with a Closed Time Path Two Particle Irreducible Effective Action at the level of Next-to-Leading-Order large N approximation. This model may be regarded as a field theory in 00 space dimensions.Comment: 22 page

    Nonequilibrium Quantum Dynamics Of Disoriented Chiral Condensates

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    The nonequilibrium dynamics of the chiral phase transition expected during the expansion of the quark-qluon plasma produced in a high energy hadron or heavy ion collision is studied in the O(4) linear sigma model to leading order in a large NN expansion. Starting from an approximate equilibrium configuration at an initial proper time τ\tau in the disordered phase we study the transition to the ordered broken symmetry phase as the system expands and cools. We give results for the proper time evolution of the effective pion mass, the order parameter as well as for the pion two point correlation function expressed in terms of a time dependent phase space number density and pair correlation density. We determine the phase space of initial conditions that lead to instabilities (exponentially growing long wave length modes) as the system evolves in time. These instabilities are what eventually lead to disoriented chiral condensates. In our simulations,we found that instabilities that are formed during the initial phases of the expansion exist for proper times that are at most 3fm/c3 fm/c and lead to condensate regions that do not contain large numbers of particles. The damping of instabilities is a consequence of strong coupling.Comment: 49 pages, figures available by reques

    Multiwavelength Observations of Supersonic Plasma Blob Triggered by Reconnection Generated Velocity Pulse in AR10808

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    Using multi-wavelength observations of Solar and Heliospheric Observatory (SoHO)/Michelson Doppler Imager (MDI), Transition Region and Coronal Explorer (TRACE) 171 \AA, and Hα\alpha from Culgoora Solar Observatory at Narrabri, Australia, we present a unique observational signature of a propagating supersonic plasma blob before an M6.2 class solar flare in AR10808 on 9th September 2005. The blob was observed between 05:27 UT to 05:32 UT with almost a constant shape for the first 2-3 minutes, and thereafter it quickly vanished in the corona. The observed lower bound speed of the blob is estimated as ∌\sim215 km s−1^{-1} in its dynamical phase. The evidence of the blob with almost similar shape and velocity concurrent in Hα\alpha and TRACE 171 \AA\ supports its formation by multi-temperature plasma. The energy release by a recurrent 3-D reconnection process via the separator dome below the magnetic null point, between the emerging flux and pre-existing field lines in the lower solar atmosphere, is found to be the driver of a radial velocity pulse outwards that accelerates this plasma blob in the solar atmosphere. In support of identification of the possible driver of the observed eruption, we solve the two-dimensional ideal magnetohydrodynamic equations numerically to simulate the observed supersonic plasma blob. The numerical modelling closely match the observed velocity, evolution of multi-temperature plasma, and quick vanishing of the blob found in the observations. Under typical coronal conditions, such blobs may also carry an energy flux of 7.0×106\times10^{6} ergs cm−2^{-2} s−1^{-1} to re-balance the coronal losses above active regions.Comment: Solar Physics; 22 Pages; 8 Figure

    Altered H19/miR‐675 expression in skeletal muscle is associated with low muscle mass in community‐dwelling older adults

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    Background: Despite increasing knowledge of the pathogenesis of muscle ageing, the molecular mechanisms are poorly understood. Based on an expression analysis of muscle biopsies from older Caucasian men, we undertook an in-depth analysis of the expression of the long non-coding RNA, H19, to identify molecular mechanisms that may contribute to the loss of muscle mass with age. Methods: We carried out transcriptome analysis of vastus lateralis muscle biopsies from 40 healthy Caucasian men aged 68–76 years from the Hertfordshire Sarcopenia Study (HSS) with respect to appendicular lean mass adjusted for height (ALMi). Validation and replication was carried out using qRT-PCR in 130 independent male and female participants aged 73–83 years recruited into an extension of the HSS (HSSe). DNA methylation was assessed using pyrosequencing. Results: Lower ALMi was associated with higher muscle H19 expression (r2 = 0.177, P < 0.001). The microRNAs, miR-675-5p/3p encoded by exon 1 of H19, were positively correlated with H19 expression (Pearson r = 0.192 and 0.182, respectively, P < 0.03), and miR-675-5p expression negatively associated with ALMi (r2 = 0.629, P = 0.005). The methylation of CpGs within the H19 imprinting control region (ICR) were negatively correlated with H19 expression (Pearson r = −0.211 to −0.245, P ≀ 0.05). Moreover, RNA and protein levels of SMAD1 and 5, targets of miR-675-3p, were negatively associated with miR-675-3p (r2 = 0.792 and 0.760, respectively) and miR-675-5p (r2 = 0.584 and 0.723, respectively) expression, and SMAD1 and 5 RNA levels positively associated with greater type II fibre size (r2 = 0.184 and 0.246, respectively, P < 0.05). Conclusions: Increased expression profiles of H19/miR-675-5p/3p and lower expression of the anabolic SMAD1/5 effectors of bone morphogenetic protein (BMP) signalling are associated with low muscle mass in older individuals
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