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Powder Mixed (powder + mixed)
Selected AbstractsMicrowave Assisted Synthesis of Yb:Y2O3 Based Materials for Laser Source Application,ADVANCED ENGINEERING MATERIALS, Issue 3 2010Anna Luisa Costa Yb:Y2O3 submicrometric particles were synthesized through co-precipitation of Yb and Y nitrate in water. Microwave heating and controlled release of ammonia through urea decomposition at reaction temperature leaded to the formation of disaggregated, monosized spherical particles of carbo-hydroxy-nitrate precursors. Pure crystalline Yb:Y2O3 powder that preserved the described morphology was obtained after calcination in air at 800,°C for 30,min. This powder mixed with commercial alumina powder was used to produce transparent Yb:YAG ceramics. Improved properties in terms of powder morphology and reactivity were presented in comparison with powders obtained by traditional heating. [source] An in-vitro investigation of the antibacterial effect of nisin in root canals and canal wall radicular dentineINTERNATIONAL ENDODONTIC JOURNAL, Issue 10 2004S. R. Turner Abstract Aim, To determine whether nisin, a bacteriocin, would be effective at killing Enterococcus faecalis and Streptococcus gordonii cells in solution and within the root canal system. Methodology, Bacterial isolates of E. faecalis and S. gordonii were grown from glycerol stocks in closed tubes containing BHY broth at 37 °C. The minimum bactericidal concentration (MBC) of nisin for both bacterial species was determined by a microdilution method. Extracted human teeth were decoronated to produce roots of equal length with a single canal and divided into six groups of 10 roots. The canals were prepared to a master apical size 30 file using 0.04 taper Ni-Ti rotary instruments. Bacterial samples of each species were inoculated into three groups of prepared roots and incubated in closed tubes at 37 °C for 21 days. The root canals in each group were then medicated with water (control), calcium hydroxide powder mixed with sterile water [Ca(OH)2], or nisin and incubated for a further 7 days. Rotary Ni-Ti files were used to take radicular dentine samples from the walls of each canal which were then incubated in BHY broth for 24 h. Optical density (OD600) readings were taken as a measure of bacterial growth. Results, The MBC of nisin for E. faecalis and S. gordonii was 70 and 20 mg mL,1 respectively. Calcium hydroxide and nisin medication eradicated infection within the root canal while cells remained viable in the control group. Mean optical density (OD600) readings from canal wall dentine shavings infected with E. faecalis were 1.32 ± 0.98, 0.73 ± 0.27 and 0.69 ± 0.38 for the control, Ca(OH)2 and nisin samples respectively. Corresponding mean readings for S. gordonii were 1.19 ± 0.18, 0.73 ± 0.15 and 0.60 ± 0.29. The Ca(OH)2 and nisin group readings were significantly (P < 0.01) lower than the control for each species as tested by Student's t -test and Mann,Whitney U statistical analysis. Values for Ca(OH)2 and nisin were not significantly (P > 0.01) different. Conclusion, Nisin was effective at eradicating E. faecalis and S. gordonii cells in pure culture and was comparable with Ca(OH)2 in the elimination of these species from within the root canal system. [source] Is the effect of probiotics on atopic dermatitis confined to food sensitized children?CLINICAL & EXPERIMENTAL ALLERGY, Issue 5 2006D. Sistek Summary Background Probiotics have previously been shown to reduce the severity of atopic dermatitis (AD) in infants and children. Objective To examine the effect of two probiotics (Lactobacillus rhamnosus and Bifidobacteria lactis) on established AD in children. Subjects and methods Atopic children with current dermatitis received 2 × 1010 colony forming units/g of probiotic (n=29) or placebo (n=30). Both were given daily as a powder mixed with food or water. SCORing Atopic Dermatitis (SCORAD; developed by the European Task Force on Atopic Dermatitis) a measure of the extent and severity of AD, was assessed at baseline, 2 and 12 weeks after starting treatment and 4 weeks after treatment was discontinued. Results SCORAD geometric mean score at baseline was 26.0 (21.9,30.8) in the probiotic group and 35.1 (28.9,42.8) in the placebo group (P=0.02). After adjustment for these between-group baseline differences there was no significant improvement in AD at 12 weeks, SCORAD geometric mean ratio: 0.80 (95% confidence level (CI) 0.62,1.04, P=0.10). Among the food sensitized children, there was an improvement in those treated with probiotics, SCORAD geometric mean ratio: 0.73 (95% CI 0.54,1.00, P=0.047). Conclusion In this study a combination of Lactobacillus rhamnosus and Bifidobacteria lactis improved AD only in food sensitized children. [source] Synthesis of ultrafine titanium carbonitride powders,APPLIED ORGANOMETALLIC CHEMISTRY, Issue 5 2001Frederic Monteverde Abstract Titanium-carbonitride-based materials are very hard materials with increasing technical importance. They are mainly used in composites with various metal carbides and/or metallic binders (cermets) for metal cutting operations. These applications call for the synthesis of titanium carbonitride powders with homogeneous chemical composition, as small as possible grain size and narrower grain size distribution. Nowadays on the market, only commercial submicrometric (0.5,2,,m) powders are available. Starting from blends of nanosize commercial TiN or TiO2 powders mixed with different carbon powders (carbon black, active carbon), this study aimed to set up a low-cost process to synthesize fine and pure TiC1,X,NX powders with an X value close to 0.5. The morphology of the as-obtained powders and the progress of the reaction were investigated by scanning electron microscopy and X-ray diffraction. The stoichiometric parameter X was estimated on the basis of a TiC1,X,NX Raoultian solid solution together with Vegard's rule. The results are presented and discussed to assess relations between powder characteristics and processing conditions. The most encouraging results were obtained using a mixture TiN,+,10,wt%C (carbon black) processed at 1430,°C for 3,h under flowing argon. Regularly shaped particles with limited agglomeration ranged from 100 to 300,nm and an X value close to 0.5 Copyright © 2001 John Wiley & Sons, Ltd. [source] | ||||||||||