MgSiN2 Addition as a Means of Increasing the Thermal Conductivity of β-Silicon Nitride

Si₃N₄ powders with the concurrent addition of Yb₂O₃ and MgSiN₂ were sintered at 1900°C for 2–48 h under 0.9 MPa nitrogen pressure. Microstructure, lattice oxygen content, and thermal conductivity of the sintered specimens were evaluated and compared with Si₃N₄, Yb₂O₃, and MgO addition. MgSiN₂ addition was effective for improving the thermal conductivity of Si₃N₄ ceramics, and a material with high thermal conductivity over 140 W·(m·K)⁻¹ could be obtained. For both specimens, lattice oxygen content was decreased with sintering time. However, the thermal conductivity of the MgSiN₂-doped specimen was slightly higher than the MgO-doped specimen with the same oxygen content.     

Polyether-segmented nylon hemodialysis membranes. I. Preparation and permeability characteristics of polyether-segmented nylon 610 hemodialysis membrane

The effect of the coagulation condition in the phase inversion method on the permeability characteristics of poly(propylene oxide) or poly(tetramethylene oxide)-segmented nylon 610 (PPO-Ny610 or PTMO-Ny610) hemodialysis membranes, the stability of the membrane performance, and the mechanical strength were investigated. The polymers were dissolved in a solvent such as formic acid and methanol saturated with calcium chloride, and thus PPO-Ny610 and PTMO-Ny610 membranes were prepared using formic acid and a calcium chloride/methanol/water mixture as a polymer solvent and a coagulant, respectively. It is concluded that PPO-Ny610 membrane has better permeability characteristics than PTMO-Ny610 membrane, and possesses additional properties for hemodialysis membranes such as mechanical properties and permeability stability in the drying and sterilizing processes. Furthermore, the blood compatibilities of PPO-Ny610 and PTMO-Ny610 membranes were superior to regenerated cellulose membranes on the basis of the result of platelet adhesion test. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1703–1711, 1997     

Knee Osteoarthritis Progression Is Delayed in Silent Information Regulator 2 Ortholog 1 Knock-in Mice

Overexpression of silent information regulator 2 ortholog 1 (SIRT1) is associated with beneficial roles in aging-related diseases; however, the effects of SIRT1 overexpression on osteoarthritis (OA) progression have not yet been studied. The aim of this study was to investigate OA progression in SIRT1-KI mice using a mouse OA model. OA was induced via destabilization of the medial meniscus using 12-week-old SIRT1-KI and wild type (control) mice. OA progression was evaluated histologically based on the Osteoarthritis Research Society International (OARSI) score at 4, 8, 12, and 16 weeks after surgery. The production of SIRT1, type II collagen, MMP-13, ADAMTS-5, cleaved caspase 3, Poly (ADP-ribose) polymerase (PARP) p85, acetylated NF-κB p65, interleukin 1 beta (IL-1β), and IL-6 was examined via immunostaining. The OARSI scores were significantly lower in SIRT1-KI mice than those in control mice at 8, 12, and 16 weeks after surgery. The proportion of SIRT1 and type II collagen-positive-chondrocytes was significantly higher in SIRT1-KI mice than that in control mice. Moreover, the proportion of MMP-13-, ADAMTS-5-, cleaved caspase 3-, PARP p85-, acetylated NF-κB p65-, IL-1β-, and IL-6-positive chondrocytes was significantly lower in SIRT1-KI mice than that in control mice. The mechanically induced OA progression was delayed in SIRT1-KI mice compared to that in control mice. Therefore, overexpression of SIRT1 may represent a mechanism for delaying OA progression.     

Polyether‐segmented nylon hemodialysis membrane. VII. Studies on surface structures of various poly(ethylene oxide)‐segmented nylon membranes

The relationships of the surface morphologies to the surface chemical compositions in poly(ethylene oxide)‐segmented nylon (PEO–Ny) membranes prepared by the phase‐inversion method were studied using scanning electron microscopy (SEM), electron spectroscopy for chemical analysis (ESCA), and static secondary ion mass spectrometry (SSIMS). The PEO–Ny's used were high semicrystalline PEO‐segmented polyiminosebacoyliminohexamethylene (PEO–Ny610), low semicrystalline PEO‐segmented poly(iminosebacoylimino‐m‐xylylene) (PEO–NyM10), and amorphous PEO‐ segmented poly(iminoisophthaloyliminomethylene‐1,3‐cyclohexylenemethylene) (PEO–NyBI). SEM observation showed that the surfaces of the PEO–Ny610 and PEO–NyM10 membranes were composed of crystalline spherulite and that the PEO–NyBI membrane surface had a nodular structure. ESCA analysis exhibited the enrichment of the PEO segment at the surfaces of the PEO–Ny610 and PEO–NyM10 membranes. On the other hand, the enrichment of the Ny segment was observed in the case of the PEO–NyBI membrane. SSIMS analysis revealed that the outermost surfaces of the PEO–Ny membranes except the PEO–NyBI membrane were almost covered with the PEO segment. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 517–528, 2000     

Efficient decomposition of environmentally persistent perfluorocarboxylic acids by use of persulfate as a photochemical oxidant

Photochemical decomposition of persistent perfluorocarboxylic acids (PFCAs) in water by use of persulfate ion (S2O8(2-)) was examined to develop a technique to neutralize stationary sources of PFCAs. Photolysis of S2O8(2-) produced highly oxidative sulfate radical anions (SO4-), which efficiently decomposed perfluorooctanoic acid (PFOA) and other PFCAs bearing C4-C8 perfluoroalkyl groups. The major products were F- and CO2; also, small amounts of PFCAs with shorter than initial chain lengths were detected in the reaction solution. PFOA at a concentration of 1.35 mM (typical of that in untreated wastewater after an emulsifying process in fluoropolymer manufacture) was completely decomposed by a photochemical system with 50 mM S2O8(2-) and 4 h of irradiation from a 200-W xenon-mercury lamp. The initial PFOA decomposition rate was 11 times higherthan with photolysis alone. All sulfur-containing species in the reaction solution were eventually transformed to sulfate ions by this method. This method was successfully applied to the decomposition of perfluorononanoic acid contained in a floor wax solution.     

TiO2-induced heterogeneous photodegradation of a fluorotelomer alcohol in air

Degradation of C4F9C2H4OH in air over TiO2 particles was examined in this first report of gas-solid heterogeneous photochemical degradation of fluorotelomer alcohols (FTOHs), which may be precursors of perfluorocarboxylic acids (PFCAs) in the environment. Photoirradiation (>290 nm) of C4F9C2H4OH in air flowing over TiO2 produced CO2, via C4F9CH2CHO, C4F9CHO, CnF(2n+1)COF (n=2 and/or 3), and COF2, in that order. X-ray photoelectron spectroscopy of the Ti02 surface showed a decrease in the amount of fluorine bonded to carbon and an increase in the amount of F- as the degradation of C4F9C2H4OH in air proceeded. Of the carbon content in the initial C4F9C2H4OH (78.8 ppmv), 90.7% was transformed to CO2, and the predominant fluorine species produced on the TiO2 surface was F-. Fluorotelomer unsaturated acids, which are considered to be toxic and have been observed in the biodegradation of FTOHs, did notform. Increased relative humidity in the air accelerated the decomposition of the reaction intermediates, which led to increased CO2 and F- formation. This result indicates that humidity is a key factor for counteracting FTOHs in indoor air. Although perfluoroalkyl substances such as PFCAs in water reportedly undergo little photodegradation over TiO2, our data show that mineralization of C4F9C2H4OH in air can be achieved with TiO2.     

Effect of a dietary supplement containing glucosamine hydrochloride, chondroitin sulfate and quercetin glycosides on symptomatic knee osteoarthritis: a randomized, double-blind, placebo-controlled study

BACKGROUND: Oral glucosamine and chondroitin sulfate, alone and in combination, have been used worldwide for the treatment of osteoarthritis (OA), but their efficacy is controversial. This clinical study was aimed at investigating the potential of a dietary supplement containing glucosamine and chondroitin sulfate in combination with derivatives of quercetin, a naturally occurring flavonoid, (GCQ supplement) for knee OA care. RESULTS: A randomized, double‐blind, placebo‐controlled study was conducted in 40 Japanese subjects with symptomatic knee OA. Subjects were randomly assigned to GCQ supplement (1200 mg glucosamine hydrochloride, 60 mg chondroitin sulfate and 45 mg quercetin glycosides per day) or placebo and the treatment and follow‐up were continued for 16 weeks. The results of symptomatic efficacy assessment based on Japanese Orthopaedic Association criteria showed that scores for two of the four symptom/function subscales, as well as the aggregate scores, were significantly improved at week 16 or earlier in the GCQ group compared to the placebo group. Moreover, analyses of cartilage metabolism biomarkers showed a trend of improvement in type II collagen synthesis/degradation balance in the GCQ group during follow‐up. CONCLUSION: GCQ supplement was thought to be more effective than placebo in decreasing the intensity of knee OA‐associated clinical symptoms. Copyright © 2011 Society of Chemical Industry     

Structural and Physicochemical Properties of Endosperm Starches Possessing Different Alleles at the Amylose-extender and Waxy Locus in Maize (Zea mays L.)

The structure and some physicochemical properties of endosperm starches from seven amylose-extender (ae) and two waxy (wx) alleles of maize (Zea mays L.) were studied. Starches prepared from mature kernels of six ae mutants, Oh43 inbred line ae (standard ae), ae-RWB-2 and ae-RWB-3, and W23 × L317 hybrid line ae-PP, ae-Bol 561 and ae-emll, were uniquely ae type, as was concluded from B type X-ray diffractograms; high gelatinization temperatures determined by differential scanning calorimetry (DSC); with poor starch-granule digestibility to amylase; high amylose (37—45 %) and high intermediate fraction (13—18 %) contents; and low ratios (1.0—1.2) of long α-1,4-chains to short α-1,4-chains of amylopectin determined by gel permeation chromatography (GPC) of isoamylase-debranched starches. The results also indicated that different ae alleles had different effects on the amylose content of endosperm starches. Mature kernels of Oh43 ae-RWB-1 mutant showed tarnished and translucent phenotype characteristics of the ae genotype but contained endosperm starch with 21—22 % of amylose which was lower than that of the Oh43 normal counterpart. Both wx-B and wx-C (standard wx) genes have similar effect on structure and physicochemical properties of waxy starches of A632, B37, C105, Oh43, and W64A inbred lines.     

Automatic parameter learning method for agent activation spreading network by evolutionary computation

Artificial Life and Robotics - A variety of planning research is being actively conducted in multiple research fields. The focus of these studies is to flexibly utilize both immediate and...