Yonsei University

About: Yonsei University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Cancer. The organization has 50162 authors who have published 106172 publications receiving 2279044 citations. The organization is also known as: Yonsei.

Measurement of the τ Lepton Polarization and R (D * ) in the Decay B ̄ →D * τ - ν ̄ τ

Abstract: We report the first measurement of the tau lepton polarization P-tau(D*) in the decay (B) over bar -> D* tau(-) (v) over bar (tau) as well as a newmeasurement of the ratio of the branching fractions R(D*) = B((B) over bar -> D* tau(-) (v) over bar (tau)) / B((B) over bar -> D* l(-) (v) over bar (l)), where l(-) denotes an electron or a muon, and the tau is reconstructed in the modes tau(-) -> pi(-) v(tau) and tau(-) -> rho(-) v(tau). We use the full data sample of 772 x 10(6) B (B) over bar pairs recorded with the Belle detector at the (KEKB) over bar electron-positron collider. Our results, P-tau(D*) = -0.38 +/- 0.51 (stat)(-0.16)(+0.21) (syst) and R(D*) = 0.270 +/- 0.035 (stat)(- 0.025)(+0.028) (syst), are consistent with the theoretical predictions of the standard model.

Hypoxia-enhanced wound-healing function of adipose-derived stem cells: increase in stem cell proliferation and up-regulation of VEGF and bFGF.

Abstract: Adipose-derived stem cells (ADSCs) have been shown to induce wound-healing effects. Because inflammation near the wound area induces oxygen deficiency, it is interesting to elucidate the effect of hypoxia on the function of ADSCs. In this work, we asked: (1) does hypoxia alter the wound-healing function of ADSCs? and (2) what are the major factors responsible for the alteration in the wound-healing function? Effect of hypoxia on the proliferation of ADSCs was first examined that hypoxia (2% O(2)) enhanced the proliferation of ADSCs in either the presence of serum or in the absence of serum. The conditioned medium of ADSCs harvested under hypoxia (hypoCM) significantly promoted collagen synthesis and the migration of human dermal fibroblasts, compared with that in normoxia (norCM). In the animal studies, hypoCM significantly reduced the wound area compared with norCM. Furthermore, mRNA and protein measurements showed that hypoxia up-regulated growth factors such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Inhibition of VEGF and bFGF using neutralizing antibodies reversed the migration of the wounded human dermal fibroblasts and the healing of wounds in animal experiment. Collectively, these results suggest that hypoxia increases the proliferation of ADSCs and enhances the wound-healing function of ADSCs, at least partly, by up-regulating the secretion of VEGF and bFGF.

Factors influencing chloride transport in concrete structures exposed to marine environments

Abstract: The present study concerns a literature review regarding chloride transport in terms of the diffusion coefficient ( D ) and surface chloride content ( C S ) in concrete structures exposed to a marine environment. In addition, a refined model is proposed for D and C S for time-dependent chloride transport. It is found that both D and C S are time-dependent: D decreases and C S increases with time, due to further cement hydration development. D and C S are significantly influenced by concrete mix proportion, air void content in concrete, curing methods, degree of exposure to seawater and climate. Blended cement concretes are beneficial in decreasing D , but increase C S , presumably due to a refinement of the concrete pore structures and chloride binding. An increase in the air void content in concrete increases D , but decreases C S . The C S depends on curing methods such as water, membrane and aeration. The degree of exposure to seawater does not have a clear relationship with C S : higher exposure levels did not result in a higher level of C S . Exposure in tropical areas results in higher C S in concrete jetty structures with a similar level of D , mainly due to an increased temperature and concentration of salinity. Based on these findings, a refined model for C S was proposed to provide more realistic prediction of the build-up of chlorides by chloride transport in concrete structures exposed to marine environments.