The temperature dependence of luminescence from a long-lasting phosphor exposed to ionizing radiation

The temperature dependence of luminescence from a long-lasting phosphor (LLP), SrAl₂O₄ : Eu²⁺,Dy³⁺, exposed to ionizing radiation has been measured to understand the LLP luminescence mechanism. Evaluation of the decay constants of the LLP exposed to -, β- or γ-rays at temperatures from 200 to 390 K showed that the decay constant is divided into four components ranging from 10⁻⁴ to 10⁻¹ s⁻¹ with activation energies of 0.02–0.35 eV.

Total luminous intensity from the LLP with changing irradiation temperature has its maximum value around the room temperature. Irradiation at elevated temperature (390 K) has the total luminescence pattern with monotonous decrease as temperature rises. As a result of evaluating the temperature dependence of luminescence, the luminescence mechanism is considered as follows:

Full-size image

 

Light scattering studies on crystallization in polyethylene terephthalate

The light scattering from the spherulites of polyethylene terephthalate grown near the glass transition temperature has been investigated. The Hv scattering profiles can be reproduced by the sum of the ideal spherulite scattering with the distribution of spherulite radius and the isotropic scattering from randomly oriented crystallites. The ratio of optical anisotropies in the isotropic scattering to the ideal spherulite scattering is obtained by the method established to eliminate the effects of the number density of spherulites and the coefficient depending on the experimental conditions. It is found that the anisotropy ratio is almost independent of the crystallization time and of temperature above 106 °C, while it is larger at a crystallization temperature of 103 °C. The spherulitic structure is discussed in terms of the anisotropy ratio.     

Local Epidermal Endocrine Estrogen Protects Human Melanocytes against Oxidative Stress,a Novel Insight into Vitiligo Pathology

As the outermost barrier of the body, skin is a major target of oxidative stress. In the brain, estrogen has been reported synthesized locally and protects neurons from oxidative stress. Here, we explored whether estrogen is also locally synthesized in the skin to protect from oxidative stress and whether aberrant local estrogen synthesis is involved in skin disorders. Enzymes and estrogen receptor expression in skin cells were examined first by quantitative real-time PCR and Western blot analyses. Interestingly, the estrogen synthesis enzyme was mainly localized in epidermal keratinocytes and estrogen receptors were mainly expressed in melanocytes among 13 kinds of cultured human skin cells. The most abundant estrogen synthesis enzyme expressed in the epidermis was 17β-hydroxysteroid dehydrogenase 1 (HSD17β1) localized in keratinocytes, and the most dominant estrogen receptor expressed in the epidermis was G protein-coupled estrogen receptor 1 (GPER1) in melanocytes. To investigate whether keratinocyte-derived estradiol could protect melanocytes from oxidative stress, cultured human primary epidermal melanocytes (HEMn-MPs) were treated with H₂O₂ in the presence or absence of 17β estradiol or co-cultured with HSD17β1 siRNA-transfected keratinocytes. Keratinocyte-derived estradiol exhibited protective effects against H₂O₂-induced cell death. Further, reduced expression of HSD17β1 in the epidermis of skin from vitiligo patients was observed compared to the skin from healthy donors or in the normal portions of the skin in vitiligo patients. Our results suggest a possible new target for interventions that may be used in combination with current therapies for patients with vitiligo.     

Screening of Inhibitors Targeting Heat Shock Protein 47 Involved in the Development of Idiopathic Pulmonary Fibrosis

Heat shock protein 47 (HSP47), a collagen-specific molecular chaperone, is causally related to fibrotic diseases, including idiopathic pulmonary fibrosis. The identification of Compounds that interfere with the HSP47-collagen interaction is essential for the development of relevant therapeutics. Herein, we prepared human HSP47 as a soluble fusion protein expressed in E. coli and established an assay system for HSP47 inhibitor screening. We screened a natural and synthetic Compound library established at Nagasaki University. Among 1023 Compounds, 13 exhibited inhibitory activity against human HSP47, of which three inhibited its function in a dose-dependent manner. Epigallocatechin-3-O-gallate, one of these three Compounds, is a typical polyphenol Compound derived from tea leaves. Structurally related Compounds were synthesized and examined for their activity, revealing a hydroxyl group at A-ring position 5 as important for its activity. The present findings provide valuable insight for the development of natural product-derived therapeutics for fibrotic diseases, including idiopathic pulmonary fibrosis.     

Chemical Modification of Phage-Displayed Helix-Loop-Helix Peptides to Construct Kinase-Focused Libraries

Conformationally constrained peptides hold promise as molecular tools in chemical biology and as a new modality in drug discovery. The construction and screening of a target-focused library could be a promising approach for the generation of de novo ligands or inhibitors against target proteins. Here, we have prepared a protein kinase-focused library by chemically modifying helix-loop-helix (HLH) peptides displayed on phage and subsequently tethered to adenosine. The library was screened against aurora kinase A (AurA). The selected HLH peptide Bip - 3 retained the α-helical structure and bound to AurA with a K_D value of 13.7 μM. Bip - 3 and the adenosine-tethered peptide Bip - 3 - Adc provided IC₅₀ values of 103 μM and 7.7 μM, respectively, suggesting that Bip - 3 - Adc bivalently inhibited AurA. In addition, the selectivity of Bip - 3 - Adc to several protein kinases was tested, and was highest against AurA. These results demonstrate that chemical modification can enable the construction of a kinase-focused library of phage-displayed HLH peptides.     

Association and physical gelation of ABA triblock copolymer in selective solvent

Association behavior and physical gelation mechanism of ABA triblock copolymer dissolved in B-selective solvent have been studied systematically from dilute to moderately concentrated solutions. Static and dynamic light scattering and nuclear magnetic resonance measurements for dilute solutions of poly(methyl methacrylate)-block-poly(tert-butyl acrylate)-block-poly(methyl methacrylate) (PMMA-PtBuA-PMMA) in 1-butanol (PtBuA selective solvent) indicated that PMMA-PtBuA-PMMA chains are molecularly dissolved above 50 °C. With decreasing temperature, the triblock copolymers form associated micelles consisting PMMA associated core and PtBuA shell. Linear dynamic viscoelastic measurements for solutions with moderate concentration (3.9-12.0 wt%) revealed that the system was viscous sol state at 60 °C. Drastic increase of shear storage modulus (G′) occurred with decreasing temperature, and at 25 °C, G′ showed rubbery plateau with weak frequency dependency, means the formation of elastic physical gel. The consistency between the temperature for micelle formation and that at the increase in G′ indicates that the physical gelation is owing to the network formation as the result of the association of PMMA chains and the bridging PtBuA chains connecting the PMMA cores. Master curves for the dynamic moduli were derived by time-temperature superposition along the frequency axis. Just above sol-gel transition concentration (C_gel), the master curves suggest the existence of fairy amount of aggregate that is not incorporated in the macroscopic network. With the increase in polymer concentration, the master curves become to reveal Maxwell-type viscoelasticity with narrow relaxation time distribution, suggesting the formation of transient network with easily generation and destruction of crosslinks. Concentration dependency of the plateau modulus is stronger than the theoretically expected, means the macroscopic transient network grows with polymer concentration by increasing the fraction of elastically effective bridging PtBuA chain above C_gel.     

Application of the Solvothermal Process in the Synthesis of High-performance Ag/γ-Al_2O_3 Catalysts

1 INTRODUCTION Since Cu-ZSM-5 was reported as an effective catalyst for the selective catalytic reduction (SCR) of NO by hydrocarbons in the presence of excess oxygen, the SCR of NOx has received much attention as a kind of potential technology for cleaning NOx in various oxygen-rich exhausts of diesel engine, lean burning gasoline engine and gas engine. Although a number of catalysts have been tested, to date, it still seems to be difficult to find a catalyst that is completely suit…     

Simple method of determining plasma impedance of streamer discharge in atmospheric air

For atmospheric streamer discharges using a lightning impulse generator, we demonstrate a method of determining the plasma impedance in a streamer region by analyzing the periodic attenuated discharge waveforms having high-frequency components. When the streamer region in the plasma can be treated as an equivalent series circuit model including resistance and inductance elements, the regression waveforms obtained by reducing and smoothing the discharge waveforms are analyzed in the equivalent circuit. We found that the streamer resistance increased exponentially with time after the discharge, whereas the streamer inductance and series impedance were constant at 4.0 Ω for longer than the first period of the discharge waveforms. Moreover, the slope of the regression curve increases more rapidly for the positive streamer resistance than for the negative resistance. Finally, the absolute values of the streamer impedance versus time were 3.3-19 Ω and 3.5-9.0 Ω for positive and negative discharges, respectively.     

The Visual Computing of Projector‐Camera Systems

This article focuses on real‐time image correction techniques that enable projector‐camera systems to display images onto screens that are not optimized for projections, such as geometrically complex, coloured and textured surfaces. It reviews hardware‐accelerated methods like pixel‐precise geometric warping, radiometric compensation, multi‐focal projection and the correction of general light modulation effects. Online and offline calibration as well as invisible coding methods are explained. Novel attempts in super‐resolution, high‐dynamic range and high‐speed projection are discussed. These techniques open a variety of new applications for projection displays. Some of them will also be presented in this report.