Improved quantum efficiency of Sr(Al,Si)5(O,N)7:Ce3+ by selection of Ce raw material

The luminescence properties of yellow-emitting Ce³⁺-doped Sr-containing sialon phosphor Sr(Al,Si)₅(O,N)₇:Ce³⁺ were notably improved by the Ce raw material selection. By changing the Ce raw material from oxides to nitrides or chlorides, the emission wavelength shifted to above 560 nm, which is beneficial for higher color rendering index white light-emitting diodes. This result from an increase in the covalency of the host crystal being associated with a decrease in the oxygen content. When Ce chloride was used, both the absorption and internal quantum efficiency increased, resulting in an increase in the external quantum efficiency up to 65%–72%. Inductively coupled plasma mass spectrometry, X-ray diffraction, and electron spin resonance measurements showed that the reason for the absorption increase is an increase in Ce³⁺ content and suppression of the generation of the second phase, and the reason for the increase in the internal quantum efficiency is a decrease in the host crystal absorption via suppression of anion vacancy generation. It was found that Ce chloride not only suppresses oxygen impurities but also acts as a flux that results in improved crystallinity.     

Contribution of Invariant Natural Killer T Cells to the Clearance of Pseudomonas aeruginosa from Skin Wounds

Chronic infections are considered one of the most severe problems in skin wounds, and bacteria are present in over 90% of chronic wounds. Pseudomonas aeruginosa is frequently isolated from chronic wounds and is thought to be a cause of delayed wound healing. Invariant natural killer T (iNKT) cells, unique lymphocytes with a potent regulatory ability in various inflammatory responses, accelerate the wound healing process. In the present study, we investigated the contribution of iNKT cells in the host defense against P. aeruginosa inoculation at the wound sites. We analyzed the re-epithelialization, bacterial load, accumulation of leukocytes, and production of cytokines and antimicrobial peptides. In iNKT cell–deficient (Jα18KO) mice, re-epithelialization was significantly decreased, and the number of live colonies was significantly increased, when compared with those in wild-type (WT) mice on day 7. IL-17A, and IL-22 production was significantly lower in Jα18KO mice than in WT mice on day 5. Furthermore, the administration of α-galactosylceramide (α-GalCer), a specific activator of iNKT cells, led to enhanced host protection, as shown by reduced bacterial load, and to increased production of IL-22, IL-23, and S100A9 compared that of with WT mice. These results suggest that iNKT cells promote P. aeruginosa clearance during skin wound healing.     

Adsorption of amino acids by fullerenes and fullerene nanowhiskers

We have investigated the adsorption of some amino acids and an oligopeptide by fullerene (C₆₀) and fullerene nanowhiskers (FNWs). C₆₀ and FNWs hardly adsorbed amino acids. Most of the amino acids used have a hydrophobic side chain. Ala and Val, with an alkyl chain, were not adsorbed by the C₆₀ or FNWs. Trp, Phe and Pro, with a cyclic structure, were not adsorbed by them either. The aromatic group of C₆₀ did not interact with the side chain. The carboxyl or amino group, with the frame structure of an amino acid, has a positive or negative charge in solution. It is likely that the C₆₀ and FNWs would not prefer the charged carboxyl or amino group. Tri-Ala was adsorbed slightly by the C₆₀ and FNWs. The carboxyl or amino group is not close to the center of the methyl group of Tri-Ala. One of the methyl groups in Tri-Ala would interact with the aromatic structure of the C₆₀ and FNWs. We compared our results with the theoretical interaction of 20 bio-amino acids with C₆₀. The theoretical simulations showed the bonding distance between C₆₀ and an amino acid and the dissociation energy. The dissociation energy was shown to increase in the order, Val < Phe < Pro < Asp < Ala < Trp < Tyr < Arg < Leu. However, the simulation was not consistent with our experimental results. The adsorption of albumin (a protein) by C₆₀ showed the effect on the side chains of Try and Trp. The structure of albumin was changed a little by C₆₀. In our study Try and Tyr were hardly adsorbed by C₆₀ and FNWs. These amino acids did not show a different adsorption behavior compared with other amino acids. The adsorptive behavior of mono-amino acids might be different from that of polypeptides.     

Hydrogen production through dry reforming of biogas using a porous electrochemical cell: Effects of a cobalt catalyst in the electrode and mixing of air with biogas

This paper reports the performance of porous Gd-doped ceria (GDC) electrochemical cells with Co metal in both electrodes (cell No. 1) and with Ni metal in the cathode and Co metal in the anode (cell No. 2) for CO₂ decomposition, CH₄ decomposition, and the dry reforming reaction of a biogas with CO₂ gas (CH₄ + CO₂ → 2H₂ + 2CO) or with O₂ gas in air (3CH₄ +?1.875CO₂ +?1.314O₂ → 6H₂ +?4.875CO +?0.7515O₂). GDC cell No. 1 produced H₂ gas at formation rates of 0.055 and 0.33?mL-H₂/(min?m²-electrode) per 1?mL-supplied gas/(min?m²-electrode) at 600?°C and 800?°C, respectively, by the reforming of the biogas with CO₂ gas. Similarly, cell No. 2 produced H₂ gas at formation rates of 0.40?mL-H₂/(min?m²) per 1?mL-supplied gas/(min?m²) at 800?°C from a mixture of biogas and CO₂ gas. The dry reforming of a real biogas with CO₂ or O₂ gas at 800?°C proceeded thermodynamically over the Co or Ni metal catalyst in the cathode of the porous GDC cell. Faraday's law controlled the dry reforming rate of the biogas at 600?°C in cell No. 2. This paper also clarifies the influence of carbon deposition, which originates from CH₄ pyrolysis (CH₄ → C + 2H₂) and disproportionation of CO gas (2CO → C + CO₂), on the cell performance during dry reforming. The dry reforming of a biogas with O₂ molecules from air exhibits high durability because of the oxidation of the deposited carbon by supplied air.     

Characterization of denitrifying phosphate-accumulating organisms cultivated under different electron acceptor conditions using polymerase chain reaction-denaturing gradient gel electrophoresis assay

To investigate the characteristics and the microbial diversity of denitrifying phosphate-accumulating organisms (DNPAOs) that are capable of conducting enhanced biological phosphorus removal (EBPR) using nitrate as electron acceptor, three sequencing batch reactors were operated under three different electron acceptor conditions, i.e., only oxygen, oxygen together with nitrate and only nitrate. Based on the chemical analysis concerning the biochemical transformation of each reactor, it was found that phosphate-accumulating organisms responsible for EBPR consisted of at least three populations including DNPAOs, and that the microbial community structure was changed according to the electron acceptor conditions. Also, the sludge cultivated with oxygen together with nitrate showed a drastic increase in the amount of phosphorus uptake under anoxic conditions, which suggested that a proportion of DNPAOs capable of utilizing nitrate under aerobic conditions were present. On the other hand, the change in microbial community structure depending on the type of electron acceptor was demonstrated by the analysis of the results of denaturing gradient gel electrophoresis of polymerase chain reaction-amplified 16S ribosomal DNA fragments. It was found that the bacteria commonly contained in all the reactors were Rhodocyclus sp. (96% identity) and Dechlorimonas sp. (97% identity) that belonged to the beta subclass of Proteobacteria on the basis of the analysis of the sequence excised from DGGE bands and the determination of phylogenetic affiliation. However, only the presence of Rhodocyclus sp. in all the reactors was demonstrated by fluorescent in situ hybridization analysis.     

SteelStacks艺术文化园区的骨架：胡弗梅森栈桥

正伯利恒钢铁公司是20世纪的一个工业集团,在世界范围内运作工业设施。它于1857年在宾夕法尼亚州里海谷(Lehigh Valley)创立,逐渐占据了里海河沿线1 800英亩(约728hm2)的场地。1995年,伯利恒钢铁公司停止了炼钢业务,关闭了厂房,结束了当地悠久的工业历史,以及成千上万蓝领居民与工厂密不可分的生活模式。     

The isothermal conductivity improvement in zirconia-based ceramics under 24 GHz microwave heating

Abstract Under 24-GHz millimetre-wave irradiation heating ionic conductivity of zirconia base ceramics was up to 20 times higher than that of a conventionally-heated sample at the same temperature of 400 °C. The degree of enhancement could be altered by changing the stabilising atom from Y to Yb. Enhancement of ionic conduction was prominent in the setup condition of larger self-heating ratio and larger MMW absorbing materials. The isothermal improvement of ionic conductivity under MMW irradiation would be ascribed to the non-thermal effect.     

Design and performance evaluation of a haptic interface based on MR fluids for endovascular tele-surgery

Microsystem Technologies - In this paper, a magnetorheological (MR) fluids based haptic interface has been developed in master site to provide the haptic sensation to the interventionalist during...     

Possible Reaction Mechanism for the Formation of C60 From Naphthalene: A Semi-Empirical and Ab Initio Molecular Orbital Study

Abstract

Mechanism of C₆₀ formation from naphthalenes was studied by quantum chemical calculations. a patch up process of T-shape dimerization of naphthalenes followed by the intramolecular ring fusion, all through radical reactions, was proposed for a possible mechanism for the C₆₀ formation from naphthalenes. the reaction barrier was found to be less than 60-70 kcal/mol for each reaction step in this mechanism.