Showing papers by "Yang Li published in 2007"
TL;DR: The Korea Invisible Mass Search (KIMS) experiment presents new limits on the weakly interacting massive particle (WIMP)-nucleon cross section using data from an exposure of 3409 kg.d taken with low-background CsI(Tl) crystals at the Yangyang Underground Laboratory.
Abstract: Limits on the cross section for weakly interacting massive particles (WIMPs) elastic scattering on nuclei in NaI(Tl) detectors at the Yangyang Underground Laboratory are obtained from a 2967.4 kg·day data exposure. The nuclei recoiling from the scattering process are identified by the pulse shape of the scintillation light signals that they produce. The data are consistent with a no nuclear-recoil hypothesis, and WIMP-mass-dependent 90% confidence-level upper-limits are set on WIMP-nuclei elastic scattering cross sections. These limits partially exclude the DAMA/LIBRA allowed region for WIMP-sodium interactions with the same NaI(Tl) target material. The 90% confidence level upper limit on the WIMP-nucleon spin-independent cross section is 3.26×10−4 pb for a WIMP mass of 10 GeV/c2.
221 citations
TL;DR: In this article, surface modification of ZnO nanocombs was performed through a Ti plasma immersion ion implantation (PIII) with low bias voltages ranging from 0to5kV to quench surface-originated exciton emission.
Abstract: Surface modification of ZnO nanocombs was performed through a Ti plasma immersion ion implantation (PIII) with low bias voltages ranging from 0to5kV to quench surface-originated exciton emission. The ion energy dependent surface modification on ZnO was investigated using transmission electron microscopy and temperature-dependent photoluminescence (PL). The surface exciton (SX) was clearly identified for the as-grown sample at 4.5K, and complete quenching was observed for sample treated with 5kV PIII due to surface state passivation. The SX related surface states were located within 5nm in depth from the surface corresponding to the implantation depth of 5kV PIII. Room-temperature PL enhancement of these surface-modified ZnO nanocombs was observed and discussed. The results show that PIII can become a viable technique for nanostructure surface passivation.
58 citations
TL;DR: It is suggested that aniracetam restores age- and Aβ-induced alterations in membrane fluidity or A β-induced increase in [Ca2+]i, demonstrating a possible beneficial role of anir acetam in the clinic treatment for senile dementia or Alzheimer’s disease.
Abstract: In the present study, we observed the in vitro effect of aniracetam on membrane fluidity and free calcium concentrations ([Ca2+]i) of frontal cortical (FC) and hippocampal (HP) synaptosomes of aged mice and young mice treated with amyloid-β protein (Aβ) Membrane fluidity was measured by using fluorescence anisotropy of the lipophilic probe, 1,6-diphenyl-1,3,5-hexatriene (DPH). [Ca2+]i was measured by using Fura 2-AM fluorescent spectrophotometry. We found that membrane fluidity of the FC and HP synaptosomes was decreased in 14 months old mice compared with that in 3 months old mice. Similarly, Aβ25–35 (1 µM) decreased the membrane fluidity in 3 months old mice. These effects of ageing and Aβ25–35 on membrane fluidity were restored by aniracetam in a concentration-dependent manner. Furthermore, Aβ25–35 (1 µM) largely increased [Ca2+]i in FC and HP synaptosomes in 3 months old mice, but this effect on HP synaptosomes was effectively reversed by aniracetam (1–4 mM). The present findings suggest that aniracetam restores age- and Aβ-induced alterations in membrane fluidity or Aβ-induced increase in [Ca2+]i, demonstrating a possible beneficial role of aniracetam in the clinic treatment for senile dementia or Alzheimer’s disease.
10 citations
TL;DR: Stable colloidal ZnS/CdSe/ZnS nanocrystals capped with hexadecylamine formed an effective labeling reagent for macrophages or lymphocytes and the labeling of cells was demonstrated by confocal microscopy.
Abstract: Stable colloidal ZnS/CdSe/ZnS nanocrystals capped with hexadecylamine were transferred into water by encapsulation in a protective shell of an amphiphilic polymer. The properties of the products have been investigated by dynamic lighting scattering, absorption, and photoluminescence spectroscopy. These nanocrystals, when conjugated with tuftsin in aqueous suspension, formed an effective labeling reagent for macrophages or lymphocytes. The labeling of cells was demonstrated by confocal microscopy. Hybrid bio-inorganic nanoconjugates are potentially powerful fluorescent tracking tools in biological systems.
8 citations
TL;DR: In this article, it was shown that the collinear factorization of the fragmentation functions in high energy hadron and nuclei collisions breaks down at transverse momenta k{sub T} < or approx. Q{sub s}/g due to high parton densities in the colliding hadrons and/or nuclei.
Abstract: We argue that the collinear factorization of the fragmentation functions in high energy hadron and nuclei collisions breaks down at transverse momenta k{sub T} < or approx. Q{sub s}/g due to high parton densities in the colliding hadrons and/or nuclei. We calculate, at next-to-leading order in projectile parton density and to all orders in target parton density, the double-inclusive cross-section for production of a pair of gluons in the scalar J{sup PC}=0{sup ++} channel. Using the low energy theorems of QCD we find the inclusive cross-section for {pi}-meson production.
5 citations