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.

Enhanced Production of Direct Photons in Au plus Au Collisions at root s(NN)=200 GeV and Implications for the Initial Temperature

Abstract: The production of e(+)e(-) pairs for m(e+e-) < 0.3 GeV/c(2) and 1< p(T) < 5 GeV/c is measured in p + p and Au + Au collisions at root s(NN) = 200 GeV. An enhanced yield above hadronic sources is observed. Treating the excess as photon internal conversions, the invariant yield of direct photons is deduced. In central Au + Au collisions, the excess of the direct photon yield over p + p is exponential in transverse momentum, with an inverse slope T = 221 +/- 19(stat) +/- 19(syst) MeV. Hydrodynamical models with initial temperatures ranging from T-init similar to 300-600 MeV at times of similar to 0.6-0.15 fm/c after the collision are in qualitative agreement with the data. Lattice QCD predicts a phase transition to quark gluon plasma at similar to 170 MeV.

Hepatocyte-targeting single galactose-appended naphthalimide: a tool for intracellular thiol imaging in vivo.

Abstract: We present the design, synthesis, spectroscopic properties, and biological evaluation of a single galactose-appended naphthalimide (1). Probe 1 is a multifunctional molecule that incorporates a thiol-specific cleavable disulfide bond, a masked phthalamide fluorophore, and a single galactose moiety as a hepatocyte-targeting unit. It constitutes a new type of targetable ligand for hepatic thiol imaging in living cells and animals. Confocal microscopic imaging experiments reveal that 1, but not the galactose-free control system 2, is preferentially taken up by HepG2 cells through galactose-targeted, ASGP-R-mediated endocytosis. Probe 1 displays a fluorescence emission feature at 540 nm that is induced by exposure to free endogenous thiols, most notably GSH. The liver-specificity of 1 was confirmed in vivo via use of a rat model. The potential utility of this probe in indicating pathogenic states and as a possible screening tool for agents that can manipulate oxidative stress was demonstrated in experiments wherein palmitate was used to induce lipotoxicity in HepG2 cells.

Inhibition of bacterial quorum sensing by vanilla extract

Abstract: Aims: The purpose of this study was to search for a novel quorum sensing inhibitor and analyse its inhibitory activity. Methods and Results: Quorum sensing inhibition was monitored using the Tn-5 mutant, Chromobacterium violaceum CV026. Vanilla beans (Vanilla planifolia Andrews) were extracted using 75% (v/v) aqueous methanol and added to C. violaceum CV026 cultures. Inhibitory activity was measured by quantifying violacein production using a spectrophotometer. The results have revealed that vanilla extract significantly reduced violacein production in a concentration-dependent manner, indicating inhibition of quorum sensing. Conclusions: Vanilla, a widely used spice and flavour, can inhibit bacterial quorum sensing. Significance and Impact of the Study: The results suggest that the intake of vanilla-containing food materials might promote human health by inhibiting quorum sensing and preventing bacterial pathogenesis. Further studies are required to isolate specific substances from vanilla extract acting as quorum sensing inhibitors.

Corticobasal degeneration: A clinical study of 36 cases

Abstract: The presenting features and their subsequent evolution in 36 patients with pathologically proven or clinically probable corticobasal degeneration are described. The most common initial complaint was of a unilateral 'clumsy, stiff or jerky arm' (n = 20). Typically the arm was akinetic, rigid and apraxic. In about a third of these the arm was held in a striking and characteristic fixed dystonic posture. Jerking of the arm, due to action and stimulus-sensitive myoclonus accompanied these symptoms in about a third of the cases. The next most common presentation (n = 10) was difficulty walking due to clumsiness and loss of fine motor control of one leg due to apraxia or dysequilibrium, or a combination of both. Sensory symptoms in the affected arm heralded the onset of illness in three and accompanied a motor disturbance in two cases. Presentation with dysarthria or a behavioural syndrome were rare. The symptoms progressed slowly, usually involving first the ipsilateral arm and leg, but gradually spread to affect all four limbs. After a mean follow-up of 5.2 years (range 2-8 years) gait difficulties and a supranuclear ophthalmoplegia had emerged in most patients and dysarthria and pyramidal signs were common. Higher mental function was relatively preserved in most and a cortical sensory loss was evident in a quarter of cases.