Human tyrosinase inhibitor in rum distillate wastewater

An inhibitor of human tyrosinase activity in rum distillate wastewater was isolated and identified as (S)-(+)-imperanene (1). (S)-(+)-Imperanene significantly inhibited tyrosinase isolated from HMV-II cells (IC(50) 1.85 mM). Inhibition kinetics studies revealed that imperanene is a competitive inhibitor of tyrosinase when L-3,4-dihydroxyphenylalanine is used as the substrate. The inhibitory activities of 1, O-beta-D-glucopyranosyl imperanene (2) and O-beta-D-glucopyranosyl-3-methoxyl imperanene (3) were 1>2>3.     

CNT-PyC-SiC/SiC double-layer oxidation-protection coating on C/C composite

CNT-PyC-SiC/SiC double-layer coatings were prepared by growth of CNTs on C/C followed by pyrolytic carbon deposition and SiC deposition. The microstructure and the oxidation behavior of the coatings were investigated. With increasing PyC amount in the coating, the coating showed fewer cracks and a higher oxidation resistance and thermal shock resistance. CNT-PyC played a role in improving the bonding strength between C/C and coatings, alleviating stress in SiC coating and decreasing the cracks.     

Growth of Cu2ZnSnS4 thin films on Si (100) substrates by multisource evaporation

Cu₂ZnSnS₄ films were grown on Si (100) by vacuum evaporation using elemental Cu, Sn, S and binary ZnS as sources. X-ray diffraction patterns of films grown at different substrate temperatures indicated that polycrystalline growth was suppressed and the orientational growths were relatively induced in a film grown at higher temperatures. Tetragonal structure of Cu₂ZnSnS₄ films was confirmed by studying RHEED patterns. The existence of c-axis ([001] direction) growth, two kinds of a-axis (〈100〉 direction) growth and four kinds of {112} twins which can be classified as two symmetrical pairs is proposed. Broad emissions at around 1.45 eV and 1.31 eV were observed in the photoluminescence spectrum measured at 13 K.     

Prediction of a New Ligand-Binding Site for Type 2 Motif based on the Crystal Structure of ALG-2 by Dry and Wet Approaches

ALG-2 is a penta-EF-hand Ca(2+)-binding protein and interacts with a variety of intracellular proteins. Two types of ALG-2-binding motifs have been determined: type 1, PXYPXnYP (X, variable; n = 4), in ALIX and PLSCR3; type 2, PXPGF, in Sec31A and PLSCR3. The previously solved X-ray crystal structure of the complex between ALG-2 and an ALIX peptide containing type 1 motif showed that the peptide binds to Pocket 1 and Pocket 2. Co-crystallization of ALG-2 and type 2 motif-containing peptides has not been successful. To gain insights into the molecular basis of type 2 motif recognition, we searched for a new hydrophobic cavity by computational algorithms using MetaPocket 2.0 based on 3D structures of ALG-2. The predicted hydrophobic pocket designated Pocket 3 fits with N-acetyl-ProAlaProGlyPhe-amide, a virtual penta-peptide derived from one of the two types of ALG-2-binding sites in PLSCR3 (type 2 motif), using the molecular docking software AutoDock Vina. We investigated effects of amino acid substitutions of the predicted binding sites on binding abilities by pulldown assays using glutathione-S-transferase -fused ALG-2 of wild-type and mutant proteins and lysates of cells expressing green fluorescent protein -fused PLSCR3 of wild-type and mutants. Substitution of either L52 with Ala or F148 with Ser of ALG-2 caused loss of binding abilities to PLSCR3 lacking type 1 motif but retained those to PLSCR3 lacking type 2 motif, strongly supporting the hypothesis that Pocket 3 is the binding site for type 2 motif.     

The Effect of Y<Subscript>2</Subscript>O<Subscript>3</Subscript> Buffer Layer on the Magnetic Properties of Melt-Processed YBCO Superconductor

In this study, two kinds of melt-processed YBCO samples (Y1050-1 and Y1050-2) grown on a buffer layer of Y₂O₃ addition were fabricated. The compacted powders were located on a crucible with Y₂O₃ powder freely poured and a buffer layer of pressed Y₂O₃ to avoid liquid to spread on the furnace plate. The superconducting transition temperature was determined by a standard four-point method at temperatures between 40 and 100 K. The transition temperatures of Y1050-1 and Y1050-2 were found to be 91.6 and 92.9 K at zero magnetic fields, respectively. The magnetization measurements were performed using a vibrating sample magnetometer (VSM) on the same system at 5, 40, and 77 K. The critical current densities for Y1050-1 and Y1050-2 samples were determined to be 6.5×10³ and 5.6×10³ A/cm² at 77 K in zero magnetic fields, respectively. The trapped magnetic field measurements of the samples were performed by using a Hall probe scanning device and a Fe–Nd–B permanent magnet at 77 K. It was found that the trapped magnetic field of the Y1050-1 sample is higher than that of the Y1050-2 sample.     

Measurement of the coating thickness on the back side of double-sided coated structures by means of acoustic resonant spectroscopy

This paper describes a technique for measuring the thickness of the back side coating of a double-sided coated structure using acoustic resonance. The technique is used to observe the resonant frequency of high frequency ultrasound for a steel/coating/air structure. The resonant frequency of the transmitted ultrasound occurs when a quarter wavelength corresponds to the thickness of the back side coating, and the reflection coefficient has a minimum value. The top surfaces of the samples are covered with a coating about 30 μm thick and the thickness of the back side coating is in the range of 10.3-17.5 μm. The resonant frequencies for the examined samples are observed in the frequency range of 46.8-75.6 MHz, and the thickness of the back side coating can be accurately determined from the measured resonant frequency. Note that the coating on the top surface of the structure does not affect the thickness measurement accuracy of the back side coating.     

Effect of fiber array irregularities on microscopic interfacial normal stress states of transversely loaded UD-CFRP from viewpoint of failure initiation

A detailed investigation has been carried out to determine the effect of local fiber array irregularities and controlling fiber distribution parameters on microscopic interfacial normal stress states for transversely-loaded unidirectional carbon fiber (CF)/epoxy composites. Linear elastic finite element analyses were carried out for two-dimensional image-based models composed of about 70 fibers. The relationship between the geometrical distribution of two adjacent fibers and the interfacial normal stresses (INSs) is investigated for all fibers in different image-based models. Three boundary conditions for loading were selected: Case A involved cooling from the curing temperature (the difference in temperature was ?155 K); Case B involved transverse loading of 75 MPa chosen as an example of macroscopic transverse fracture strength; and Case C involved both cooling from the curing temperature and transverse loading of 75 MPa. High compressive INSs due to the difference in the coefficients of thermal expansion are observed at the location of the shortest interfiber distance for Case A (cooling). High tensile INSs are observed at the location of the shortest interfiber distance and where the fiber alignment angle to the loading direction is small for Case B (loading). For Case C (cooling and loading), the high thermal residual compressive INSs and the high mechanical tensile INSs compensate each other, and the INSs at a short interfiber distance are much lower than those for Case B. These results clearly indicate the importance of the contribution of the thermal residual stresses to the transverse tensile failure initiation of CF/epoxy laminates.     

Damage characterisation of fibre metal laminates under interlaminar shear load

Transverse composite plies are part of the fibre metal laminate Glare^®4B and were investigated under interlaminar shear load. Double-notched shear (DNS) tests were performed and deformation and damage were in situ observed by Scanning Electron Microscopy (SEM) equipped with a loading apparatus. Interlaminar shear strength as well as shear stress values corresponding to the onset of the fibre/matrix-debonding were determined.Although a cross-ply lay-up within the laminate has been interlaminar shear loaded, damage and failure could only be found within the transverse plies. Over their thickness, fibre/matrix-debonding proved to be pronounced near the ply boundaries of the transverse plies, where exceptionally high shear strains could be found. Nevertheless, single fibre/matrix-debonding phenomena were also observed within the centre area of these transverse plies. Although interlaminar shear strain within latter regions is reduced, single events of fibre/matrix-debonding could be attributed to local high stress concentrations due to the fibre arrangement and to small inter fibre distances.     

Effect of light intensity and frequency of flashing light from blue light emitting diodes on astaxanthin production by Haematococcus pluvialis

Flashing light from blue light emitting diodes is an effective method for the reduction of energy consumption in the bioproduction of astaxanthin by Haematococcus pluvialis. We investigated the effects of light intensity and frequency on the final astaxanthin concentration in bioproduction by H. pluvialis grown mixotrophically. The final astaxanthin concentration under illumination with flashing light, with frequencies ranging from 25 to 200 Hz, was dependent on the light intensity and on the duty cycle and was equivalent, or higher, in comparison with that under illumination with continuous light at the same incident intensity. The light intensity determined the maximum attainable concentration of astaxanthin under continuous illumination. Under illumination with flashing light, the ratio of the final astaxanthin concentration to the maximum concentration at a specific light intensity was correlated to the duty cycle in the frequency range from 25 to 200 Hz. The effect of lower frequencies on enhanced astaxanthin production under flashing light was also studied; at levels as low as 1 Hz, higher final astaxanthin concentrations were observed under flashing light compared to concentrations attained under continuous light.