21,206 research outputs found
SDF1 Gene Variation Is Associated with Circulating SDF1 alpha Level and Endothelial Progenitor Cell Number-The Bruneck Study
BACKGROUND: Stromal cell-derived factor-1 (SDF1) and its receptor CXC chemokine receptor 4 (CXCR4) play a critical role in progenitor cell homing, mobilization and differentiation. It would be interesting to assess the predictive value of SDF-1alpha level for EPC number, and to ascertain whether there is a relationship between SDF1 gene variation, plasma SDF-1alpha level, and the number and function of circulating EPCs. We also tested whether EPC number and function was related to CXCR4 gene variation.
METHODOLOGY AND PRINCIPAL FINDINGS: We genotyped a cohort of individuals who participated in the Bruneck Study for single nucleotide polymorphisms (SNPs) in the SDF1 and CXCR4 genes, and measured blood SDF1alpha level as well as EPC number and function. SDF1alpha levels were correlated with age, gender, alcohol consumption, circulating reticulocyte numbers, and concentrations of matrix metalloproteinase-9, C-reactive protein, cystatin C, fibrinogen and homocytein. In blood samples taken in 2005, EPC number was inversely associated with SDF1alpha level (p<0.001). EPC number in 2005 was also inversely associated with SDF1alpha level in 2000 (p = 0.009), suggesting a predictive value of plasma SDF1alpha level for EPC number. There was an association between the SDF1 gene rs2297630 SNP A/A genotype, increased SDF1alpha level (p = 0.002) and lower EPC number (p = 0.006).
CONCLUSIONS: Our data indicate that a SDF1 gene variation (rs2297630) has an influence on SDF1alpha level and circulating EPC number, and that plasma SDF1alpha level is a predictor of EPC number
Momentum Distribution of Near-Zero-Energy Photoelectrons in the Strong-Field Tunneling Ionization in the Long Wavelength Limit
We investigate the ionization dynamics of Argon atoms irradiated by an
ultrashort intense laser of a wavelength up to 3100 nm, addressing the momentum
distribution of the photoelectrons with near-zero-energy. We find a surprising
accumulation in the momentum distribution corresponding to meV energy and a
\textquotedblleft V"-like structure at the slightly larger transverse momenta.
Semiclassical simulations indicate the crucial role of the Coulomb attraction
between the escaping electron and the remaining ion at extremely large
distance. Tracing back classical trajectories, we find the tunneling electrons
born in a certain window of the field phase and transverse velocity are
responsible for the striking accumulation. Our theoretical results are
consistent with recent meV-resolved high-precision measurements.Comment: 5 pages, 4 figure
Two Dimensional Ising Superconductivity in Gated MoS
The Zeeman effect, which is usually considered to be detrimental to
superconductivity, can surprisingly protect the superconducting states created
by gating a layered transition metal dichalcogenide. This effective Zeeman
field, which is originated from intrinsic spin orbit coupling induced by
breaking in-plane inversion symmetry, can reach nearly a hundred Tesla in
magnitude. It strongly pins the spin orientation of the electrons to the
out-of-plane directions and protects the superconductivity from being destroyed
by an in-plane external magnetic field. In magnetotransport experiments of
ionic-gate MoS transistors, where gating prepares individual
superconducting state with different carrier doping, we indeed observe a spin-
protected superconductivity by measuring an in-plane critical field
far beyond the Pauli paramagnetic limit. The
gating-enhanced is more than an order of magnitude larger
compared to the bulk superconducting phases where the effective Zeeman field is
weakened by interlayer coupling. Our study gives the first experimental
evidence of an Ising superconductor, in which spins of the pairing electrons
are strongly pinned by an effective Zeeman field
Do seasoned offerings improve the performance of issuing firms? Evidence from China
This study provides new evidence that the performance of issuing firms varies by issue type, based on survival analysis methods. Our non-parametric results show that firms raising capital through rights issues, and notably through cash offers, experience a greater risk of delisting following issuance, as compared to those issuing convertible bonds. Our Cox model analyses demonstrate that plain equity issues, in contrast to convertible issues, are subject to different degrees of regulatory discipline, obligations and incentives in shaping survival trajectory. Further, high ownership concentration, agency issues intrinsic to equity offerings, weak shareholders' protection, and corporate ownership and governance and corporate control development at the time of an offer markedly influence post-issue survival. Plain equity issues, notably cash offers, are strongly linked with the agency costs of free cash flows. A large and truly independent board, allied to a separation of CEO and chairman powers, acts as a primary restraint on managers' self-interested behaviour. Such a cohesive governance mechanism can restrain rent-seeking in the firm's fundraising initiative. These observations hold when we take into account information available before an issue, at the time of an issue, and after an issue, demonstrating the robustness of our findings
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