Cyclooxygenase-2 inhibitors modulate skin aging in a catalytic activity-independent manner

It has been proposed that the pro-inflammatory catalytic activity of cyclooxygenase-2 (COX-2) plays a key role in the aging process. However, it remains unclear whether the COX-2 activity is a causal factor for aging and whether COX-2 inhibitors could prevent aging. We here examined the effect of COX-2 inhibitors on aging in the intrinsic skin aging model of hairless mice. We observed that among two selective COX-2 inhibitors and one non-selective COX inhibitor studied, only NS-398 inhibited skin aging, while celecoxib and aspirin accelerated skin aging. In addition, NS-398 reduced the expression of p53 and p16, whereas celecoxib and aspirin enhanced their expression. We also found that the aging-modulating effect of the inhibitors is closely associated with the expression of type I procollagen and caveolin-1. These results suggest that pro-inflammatory catalytic activity of COX-2 is not a causal factor for aging at least in skin and that COX-2 inhibitors might modulate skin aging by regulating the expression of type I procollagen and caveolin-1.     

Total synthesis of (-)-dysiherbaine

The enantioselective synthesis of (-)-dysiherbaine (1) has been established with efficiency via a unique synthetic strategy involving the desymmetrization of 2-substituted glycerol to install a quaternary chiral carbon, which induces further stereochemistry in the bicyclic perhydrofuropyran through mercuriocyclization and epoxidation.     

Nanomechanical actuation driven by light-induced DNA fuel

We report the reversible nanomechanical actuation of a microcantilever driven by the light irradiation-induced conformational changes of i-motif DNA chains, which are functionalized on the cantilever's surface. It is shown that light irradiation-driven nanomechanical actuation can be manipulated using DNA hybridization and/or ionic concentrations.     

Employing electrostatic self-assembly of tailored nickel sulfide nanoparticles for quasi-solid-state dye-sensitized solar cells with Pt-free counter electrodes

A low cost, low-temperature processable, highly efficient nickel sulfide counter electrode is demonstrated. Using the tailored, preformed nickel sulfide nanoparticles and electrostatic self-assembly, a novel counter electrode was fabricated that exceeded the efficiency of a conventional Pt-based cell.     

Superparamagnetic Fe3O4 nanoparticles-carbon nitride nanotube hybrids for highly efficient peroxidase mimetic catalysts

We report a facile route to synthesize size tunable Fe(3)O(4) nanoparticles (NPs)-carbon nitride nanotube (CNNT) hybrids. These hybrids showing the water-soluble property are proven to exhibit ultra high peroxidase mimetic activity compared to those of pure NPs, where a colorless peroxidase substrate 3,3,5,5-tetramethylbenzidine changes by H(2)O(2) to its blue colored oxidized state.     

A unique tetranuclear Er(III)4 cluster exhibiting field-induced single-molecule magnetism

A tetranuclear Er(III) compound chelated with N(2)O(2) donors of a tetradentate Schiff base was produced from the self-assembly of the corresponding chemical species. This intriguing cluster shows field-induced slow relaxation of magnetization.     

Tetraglyme-mediated synthesis of Pd nanoparticles for dehydrogenation of ammonia borane

Palladium nanoparticles (PdNPs) were conveniently prepared in tetraglyme (TG) solution using a variety of palladium precursors. At 140 °C, TG promoted Pd(3)(OAc)(6) to produce irregular shaped PdNPs with an average size of 4 nm. When these PdNPs were re-dispersed in TG and used for the dehydrogenation of ammonia borane (AB) at 85 °C, remarkably enhanced catalytic performance was achieved to release 2.3 equiv. of H(2) in 1 h.     

An Analytical Self-consistent Solution for the Free Energy of a 1-D Chain of Atoms Including Anharmonic Effects

The self-consistent method of lattice dynamics (SCLD) is used to obtain an analytical solution for the free energy of a periodic, one-dimensional, mono-atomic chain accounting for fourth-order anharmonic effects. For nearest-neighbor interactions, a closed-form analytical solution is obtained. In the case where more distant interactions are considered, a system of coupled nonlinear algebraic equations is obtained (as in the standard SCLD method) however with the number of equations dramatically reduced. The analytical SCLD solutions are compared with a numerical evaluation of the exact solution for simple cases and with molecular dynamics simulation results for a large system. The advantages of SCLD over methods based on the harmonic approximation are discussed as well as some limitations of the approach.     

Optical characterization of band gap graded ZnMgO films

We investigated the optical properties of compositionally graded Zn_1?xMg_xO (g-ZnMgO) films using spectroscopic ellipsometry. The g-ZnMgO and ZnO films were grown on Pt/Ti/SiO₂/Si substrates by ultrasonic spray pyrolysis. We simulated a uniformly graded optical band gap layer on the Pt substrate to reproduce the experimental result. The band gap of the bottommost layer of the g-ZnMgO film was estimated to be ～3.22 eV, the same as the undoped ZnO film. Then we considered a linearly increasing band gap with the film composition, and obtained a band gap of ～3.56 eV for the topmost layer of the film. In addition, the exciton peak showed a strong increase for the topmost layer of the film suggesting an important role of doping.     

Synthesis and characterization of Cu2ZnSnS4 thin films by SILAR method

Semiconducting Cu₂ZnSnS₄ (CZTS) material has been receiving a great technological interest in the photovoltaic industry because of its low-cost non-toxic constituents, ideal direct band gap as a absorber layer and high absorption coefficient. CZTS thin films have been successfully deposited onto the fluorine-doped tin oxide/glass (glass/FTO) substrates coated glass substrates using successive ionic layer adsorption and reaction (SILAR) method and investigated for photoelectrochemical conversion (PEC) of light into electricity. The best solar cell sample showed an open-circuit voltage of 390 mV, a short-circuit current density of 636.9 μA/cm², a fill factor of 0.62 and an efficiency of 0.396% under irradiation of 30 mW/cm². Preliminary results obtained for solar cells fabricated with this material are promising.