Depigmenting activity and low cytotoxicity of alkoxy benzoates or alkoxy cinnamte in cultured melanocytes

To obtain effective and safe topical depigmenting agents, we synthesized hydroxybenzoates, alkoxybenzoates, and 3,4,5-trimethoxycinnamate containing a thymol moiety and screened then for high-level inhibitory activity against melanin synthesis in cultured melanocytes. Eight compounds were tested for their depigmenting effect and cytotoxicity using a murine melanocyte cell line. We found that 3,4,5-trialkoxybenzoates and 3,4,5-trimethoxycinnamate, synthesized by conjugating 3,4,5-trialkoxybenzoic acids and 3,4,5-trimethoxycinnmic acid with thymol, showed a potent depigmenting effect and low cytotoxicity. Compound 4h, 5-methyl-2-(methylethyl)phenyl (2E)-3-(3,4,5-trimethoxyphenyl)prop-2-enoate, showed the most potent depigmenting effect (IC50=10 microM) with low cytotoxicity (IC50=200 microM).     

Structural determination of cerebrosides isolated from Asterias amurensis starfish eggs using high-energy collision-induced dissociation of sodium-adducted molecules

Six cerebrosides were isolated from the eggs of the starfish Asterias amurensis using solvent extraction, silica gel column chromatography, and reversed‐phase high‐performance liquid chromatography. This study demonstrated that the structures of cerebrosides could be completely characterized, based on their sodium‐adducted molecules, using fast atom bombardment (FAB) tandem mass spectrometry. The high‐energy collision‐induced dissociation of the sodium‐adducted molecule, [M + Na]⁺, of each cerebroside molecular species generated abundant ions, providing information on the compositions of the 2‐hydroxy fatty acids and long‐chain sphingoid bases, as well as the sugar moiety polar head group. Each homologous ion series along the fatty acid and aliphatic chain of the sphingoid base was useful for locating the double‐bond positions of both chains and the methyl branching position of the long‐chain base. The N‐fatty acyl portions were primarily long‐chain saturated or monoenoic acids (C16 to C24) with an α‐hydroxy group. The sphingoid long‐chain base portions were aliphatic chains (C18 or C22) with two or three degrees of unsaturation and with or without methyl branching. Copyright © 2011 John Wiley & Sons, Ltd.     

PMA-induced up-regulation of MMP-9 is regulated by a PKCalpha-NF-kappaB cascade in human lung epithelial cells

Expression of matrix metalloproteinase-9 (MMP-9) is associated with airway remodeling and tissue injury in asthma. However, little is known about how MMP-9 is up-regulated in airway epithelial cells. In this study, we show that phorbol myristate acetate (PMA) induces MMP-9 expression via a protein kinase Calpha (PKCalpha)-dependent signaling cascade in BEAS-2B human lung epithelial cells. Pretreatment with either GF109203X, a general PKC inhibitor, or Go6976, a PKCalpha/beta isozyme inhibitor, inhibited PMA-induced activation of the MMP-9 promoter, as did transient transfection with PKCalpha antisense oligonuclotides. PMA activated NF-kappaB by phosphorylating IkappaB in these cells and this was also inhibited by GF109203X and Go6976, suggesting that PKCa acts as an upstream regulator of NF-kappaB in PMA-induced MMP-9 induction. Our results indicate that a "PKCalpha-NF- kappaB"-dependent cascade is involved in the signaling leading to PMA-induced MMP-9 expression in the lung epithelium.     

Total synthesis and absolute stereochemistry of (9R,10S)-epoxyheptadecan-4,6-diyn-3-one, a diacylglycerol acyltransferase inhibitor from Panax ginseng

Asymmetric synthesis of four possible stereoisomers of (9,10)-epoxyheptadecan-4,6-diyn-3-one was accomplished, and the absolute configuration of the naturally occurring (9R,10S)-epoxyheptadecan-4,6-diyn-3-one (1) was elucidated.     

Quark condensation, induced symmetry breaking and color superconductivity at high density

The phase structure of hadronic matter at high density relevant to the physics of compact stars and relativistic heavy-ion collisions is studied in a low-energy effective quark theory. The relevant phases that figure are (1) chiral condensation, (2) diquark color condensation (color superconductivity) and (3) induced Lorentz-symmetry breaking (“ISB”). For a reasonable strength for the effective four-Fermi current–current interaction implied by the low-energy effective quark theory for systems with a Fermi surface we find that the “ISB” phase sets in together with chiral symmetry restoration (with the vanishing quark condensate) at a moderate density while color superconductivity associated with scalar diquark condensation is pushed up to an asymptotic density. Consequently, color superconductivity seems rather unlikely in heavy-ion collisions although it may play a role in compact stars. Lack of confinement in the model makes the result of this analysis only qualitative but the hierarchy of the transitions we find seems to be quite robust.     

Nuclear axial currents from scale-chiral effective field theory

By incorporating hidden scale symmetry and hidden local symmetry in the nuclear effective field theory,combined with the double soft-pion theorem, we predict that the Gamow-Teller operator coming from the space component of the axial current should remain unaffected by the QCD vacuum change caused by the baryonic density,whereas the first forbidden beta transition operator coming from the time component should be strongly enhanced.While the latter has been confirmed for some time, the former was given support by a powerful recent ab initio quantum Monte Carlo calculation for light nuclei, which also confirmed the old?chiral filter hypothesis." Formulated in terms of the Fermi-liquid fixed point structure of strong-coupled nuclear interactions, we offer an extremely simple resolution to the long-standing puzzle of the?quenched g A," g_A~(eff) ≈1 [1], found in nuclear Gamow-Teller beta transitions, giant Gamow-Teller resonances, and double beta decays.     

Raman study of InAs/GaAs quantum dot solar cells

We report polarized and resonant Raman study of InAs/GaAs quantum dot solar cell (QDSC) structures. Raman spectra obtained from the top surfaces of the samples suggested that the formation of InAs QDs induced tensile strain in the overgrown GaAs layers. Furthermore, a longitudinal optical phonon-plasmon (LPP) coupled modes were observed in the p-type GaAs layers. The tensile strain was increased with an increase in the QD size. The hole concentrations estimated by fitting the individual LPP coupled modes were in the range of 2.4–3.5 × 10¹⁸ cm^?3. Resonant Raman spectra obtained from the cleaved sides, where the QDs were located, showed a 225 cm^?1 mode in parallel polarization configurations. Based on accurate analysis, this mode was identified as the LA(X) phonon of GaAs.     

Pseudoconformal equation of state in compact-star matter from topology change and hidden symmetries of QCD

We construct a new effective field theory approach to the equation of state(EoS), dubbed pseudo-confomal model "PCM", for nuclear and compact star matter entirely in terms of effective hadron degrees of freedom. The possible transition at n ～(2-4)n_0(where n_0 is the normal nuclear matter density) from hadron degrees of freedom to strongly-coupled quark degrees of freedom,giving rise to a soft-to-hard changeover in the EoS that can accommodate the massive stars observed, is effectuated by the topology change at n_(1/2)～ 2n_0 from skyrmions to half-skyrmions without involving local order-parameter fields. The mechanism exploits possible emergence of hidden scale and local symmetries of QCD at high density, leading to a precocious "pseudo-conformal"sound velocity v_s~2= 1/3(in unit of c = 1) for n～ 3n_0. The resulting prediction signals a drastic departure from standard nuclear many-body theory in the density regime involved in the massive stars. We suggest that the tidal deformability implemented in gravitational waves coming from coalescing neutron stars in LIGO/Virgo-type observations could pin down the location of the topology change density n_(1/2).