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Appropriate Amount (appropriate + amount)
Selected AbstractsTissue Engineering Strategies Designed to Realize the Endogenous Regenerative Potential of Peripheral NervesADVANCED MATERIALS, Issue 46 2009Vivek Mukhatyar Abstract http://doi.wiley.com/10.1002/adma.v21:32/33 Bridging peripheral nerve gaps without the use of autografts has significant clinical importance. But in order to rationally design novel scaffolds, a good understanding of the nerve regeneration process is vital. Appropriate amount of structural and chemical cues are required to stimulate the endogenous mechanisms of repair and functional recovery. Synthetic and natural materials present various opportunities to induce the growth of supporting cells as well as promote axon regeneration. An overview of tissue engineering strategies currently being explored that stimulate the different steps of the regenerative sequence is presented. [source] Cyst-based toxicity tests XIII,Development of a short chronic sediment toxicity test with the ostracod crustacean Heterocypris incongruens: Methodology and precisionENVIRONMENTAL TOXICOLOGY, Issue 6 2002Belgis Chial Abstract Experiments were carried out with neonates of the freshwater ostracod Heterocypris incongruens to verify and complete previous choices of test parameters for a new culture/maintenance-free solid-phase microbiotest for freshwater sediments. From trials with increasing volumes of reference sediment, it was concluded that 300 ,L was the most appropriate amount of substrate to be put in 12-cup multiwell plates with 2 mL of standard freshwater. Tests in 3,9 replicates eventually showed that six parallels were needed to have good assay precision (repeatability). Application of the final test protocol to oil-contaminated sediments from the St. Lawrence River in Canada revealed that the 6-day chronic ostracod microbiotest had less variation in repeated tests than did the 10-day contact assay with Hyalella azteca and hence can be considered more precise. Based on the 95% confidence intervals for mortality and growth of the ostracods in the controls (reference sediment) of the 56 tests carried out for the Canadian project, a validity threshold of 20% for mortality was eventually selected, in analogy with the acceptability limits applied in many chronic bioassays. A minimum length of 600 ,m in the control sediment after 6 days' exposure was also taken as the threshold for good health of the test organisms and for reliable test conditions. The new microbiotest has been tailored in a handy and user-friendly new toxkit, the Ostracodtoxkit, which is particularly suited for cost-effective routine monitoring. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 528,532, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10086 [source] Seasonal confounding and residual correlation in analyses of health effects of air pollutionENVIRONMETRICS, Issue 4 2007Isabella R. Ghement Abstract To investigate the health effects of air pollution via a partially linear model, one must choose an appropriate amount of smoothing for accurate estimation of the linear pollution effects. This choice is complicated by the dependencies between the various covariates and by the potential residual correlation. Most existing approaches to making this choice are inadequate, as they neither target accurate estimation of the linear pollutant effects nor handle residual correlation. In this paper, we illustrate two new adaptive and objective methods for determining an appropriate amount of smoothing. We construct valid confidence intervals for the linear pollutant effects, intervals that account for residual correlation. We use our inferential methods to investigate the same-day effects of PM10 on daily mortality in two data sets for the period 1994 to 1996: one collected in Mexico City, an urban area with high levels of air pollution, and the other collected in Vancouver, British Columbia, an urban area with low levels of air pollution. For Mexico City, our methodology does not detect a PM10 effect. In contrast, for Vancouver, a PM10 effect corresponding to an expected 2.4% increase (95% confidence interval ranging from 0.0% to 4.7%) in daily mortality for every 10,µg/m3 increase in PM10 is identified. Copyright © 2006 John Wiley & Sons, Ltd. [source] Effects of SiO2 nanoparticles on the performance of carboxyl-randomized liquid butadiene,acrylonitrile rubber modified epoxy nanocompositesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2007Minfeng Zeng Abstract The effects of SiO2 nanoparticles on the performance of carboxyl-randomized liquid butadiene,acrylonitrile rubber (CRBN) modified epoxy resin (EP) nanocomposites were studied. With the addition of an appropriate amount of SiO2 (2%) to EP/CRBN (95/5), the nanocomposites could achieve the desired impact strength and modulus. The morphology of the nanocomposites was studied with scanning electron microscopy and transmission electron microscopy. The nanocomposites showed a three-phase system; both the rubber particles and SiO2 nanoparticles showed uniform dispersions in the EP matrix, with their phases all nanosized. A good correlation between the free-volume hole radius and mechanical properties was found. The introduction of a small amount of nanoparticles (both rubber and SiO2) into EP led to the formation of interactions between the EP and nanoparticles. The interactions restricted the segment motion and the mobilization of the EP chains and then reduced the free-volume concentration in the amorphous region of EP. The fact that the average free-volume hole radius of EP/CRBN was larger than that of pure EP was mainly attributed to the contribution of the larger size of the free-volume holes within the rubber phase. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [source] Microwave Dielectric Properties of Sintered Alumina Using Nano-Scaled Powders of , Alumina and TiO2JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2007Cheng-Liang Huang The microstructure and the microwave dielectric properties of nano-scaled , alumina (,-Al2O3) ceramics with various added amounts of nano-scaled TiO2 have been investigated. The sintering temperature of nano-scaled , alumina can be effectively lowered by increasing the TiO2 content. The Q×f values of nano-scaled , alumina could be tremendously boosted by adding an appropriate amount of TiO2. However, introducing excessive TiO2 into the alumina ceramics would instead lead to a decrease in the Q×f values. The phases of TiO2 and Al2TiO5 co-existed at 1350°C, and the maximum Q×f value appeared right after the eradication of TiO2 phase at 1400°C. Consequently, increasing the TiO2 content to 0.5 wt% yielded a Q×f value of 680 000 GHz (measured at 14 GHz) for nano-scaled , alumina prepared at 1400°C for duration of 4 h. In addition, a very low loss tangent (tan ,) of 2 × 10,5 was also obtained at 14 GHz. The ,f value is strongly correlated to the compositions and can be controlled through the existing phases. In fact, ,f could be adjusted to near zero by adding 8 wt% TiO2 to , alumina ceramics. A dielectric constant (,r) of 10.81, a high Q×f value of 338 000 GHz (measured at 14 GHz), and a temperature coefficient of resonant frequency (,f) of 1.3 ppm/°C were obtained for nano-scaled , alumina with 8 wt% TiO2 sintered at 1350°C for 4 h. Sintered ceramic samples were also characterized by X-ray diffraction and scanning electron microscopy. [source] Influence of Impurities on Dispersion Properties of Bayer AluminaJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2004J. Kiennemann Among the different impurities contained in Bayer alumina (Ca, Fe, Na, Si, Mg), calcium was found to greatly influence the dispersion of alumina particles in water. Up to 90% of calcium is dissolved at acidic pH, whereas calcium remains on the alumina surface in the basic pH range and screens the negative Al,O, charges. The presence of calcium, through reducing repulsive interactions between particles, has a negative effect on the dispersion of alumina. The adsorption of the Na+ salt of poly(acrylic acid) (PAA-Na) is strongly influenced by Ca2+/PAA-Na interactions in suspension with an increase of the maximum adsorbed amount of PAA-Na in the presence of calcium. The amount of PAA-Na needed to reach a high electrostatic repulsion and a minimum of viscosity is 2 times higher in the presence of 400 pm calcium than for a low calcium content (,80 ppm). Finally, with an appropriate amount of PAA-Na, a similar state of dispersion can be reached with or without the presence of calcium. [source] Whey protein isolate coating on LDPE film as a novel oxygen barrier in the composite structurePACKAGING TECHNOLOGY AND SCIENCE, Issue 1 2004Seok-In Hong Abstract To examine the feasibility of whey protein isolate (WPI) coating as an alternative oxygen barrier for food packaging, heat-denatured aqueous solutions of WPI with various levels of glycerol as a plasticizer were applied on corona-discharge-treated low-density polyethylene (LDPE) films. The resulting WPI-coated LDPE films showed good appearance, flexibility and adhesion between the coating and the base film, when an appropriate amount of plasticizer was added to the coating formulations. WPI-coated LDPE films showed significant decrease in oxygen permeability (OP) at low to intermediate relative humidity, with an Arrhenius behaviour and an activation energy of 50.26,kJ/mol. The OP of the coated films increased significantly with increasing relative humidity, showing an exponential function. Although the coated films showed a tendency to have less oxygen barrier and more glossy surfaces with increasing plasticizer content, differences in the OP and gloss values were not significant. Haze index and colour of the coated films were also little influenced by WPI coating and plasticizer content. The results suggest that whey protein isolate coating could work successfully as an oxygen barrier and have potential for replacing synthetic plastic oxygen-barrier layers in many laminated food packaging structures. Copyright © 2004 John Wiley & Sons, Ltd. [source] Polymer electrolyte using in situ quanternization for all solid-state dye-sensitized solar cellsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 6 2009Wanchun Xiang Abstract Polymer electrolyte through in situ quanternization reaction by oligo-siloxane containing quanternary ammonium groups was synthesized for all solid-state dye-sensitized solar cells (DSSCs). These two latent crosslinked precursors are oligo-organosiloxane grafting oligo-ethylene oxide and propylene oxide dimethylamine (OEA) and the oligo-organosiloxane grafting oligo-ethylene oxide and propylene oxide bromide (OEB). This chemically crosslinked electrolyte shows good ambient conductivity of 2.6,×,10,4,S/cm when incorporating appropriate amount of 1-iodide oligo-ethylene glycol monomethylether (IOEGMME) as an additive. Photoelectrochemical performances for different electrolytes were also analyzed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Structure and properties of double- C,N -chelated tri- and diorganotin(IV) halidesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 10 2005Petr Novák Abstract Tri- and di-organotin(IV) compounds containing one or two 2-(dimethylaminomethyl)phenyl- (LCN) groups as chelating ligands were prepared by reactions of lithium compound LCNLi with an appropriate amount of (organo)tin halide. The geometry of tin in 1 ((LCN)2SnPhCl) is on the boundary between octahedral and trigonal bipyramidal. The diorganotin compounds 2,4 ((LCN)2SnX2, where X = Cl, Br, I) have a distorted octahedral geometry in the solid state and show dynamic processes in solution with a lowering of activation energy of the dynamic process going from diiodide to dichloride derivative. Compound 5 (LCNSnPhCl2) has a trigonal bipyramidal structure with non-equivalent chlorine atoms. Copyright © 2005 John Wiley & Sons, Ltd. [source] The Response of Articular Chondrocytes to Type II Collagen,Au NanocompositesARTIFICIAL ORGANS, Issue 12 2007Shan-hui Hsu Abstract:, The nanocomposites (denoted "CII,Au") of porcine type II collagen (CII) with 0.05, 0.1, 0.5, 1, or 2.5% (wt/wt) Au nanoparticles (,5 nm) were fabricated for potential use in cartilage tissue engineering. Au formed clusters on the surface of all nanocomposites and appeared to distribute along the collagen fibrils inside the matrix. The addition of Au at low concentrations (,0.5%) increased the modulus and viscosity, as well as the free radical-scavenging ability. These effects decreased at higher concentrations of Au. The chondrocytes on CII,Au became spindle-like with lamellipodia formation. Cell proliferation on CII,Au 0.1% was promoted. Nitric oxide (NO) in the culture medium was reduced by CII,Au 0.05% and CII,Au 0.1%. Type I collagen, aggrecan, and Sox 9 gene expressions increased with an increased Au content, but slightly decreased at 2.5% Au. There was no significant difference in the CII gene expression. The cellular uptake of Au was observed but less than that which occurred when 10 ppm of Au was added in culture medium. Chondrocytes cultured with ,10 ppm of Au nanoparticles showed neither cytotoxicity nor change in gene expression. Au at an appropriate amount could be well dispersed in CII, and enhanced the material modulus, antioxidant effect, as well as the chondrocyte growth and matrix production. [source] Generalized Additive Modeling with Implicit Variable Selection by Likelihood-Based BoostingBIOMETRICS, Issue 4 2006Gerhard Tutz Summary The use of generalized additive models in statistical data analysis suffers from the restriction to few explanatory variables and the problems of selection of smoothing parameters. Generalized additive model boosting circumvents these problems by means of stagewise fitting of weak learners. A fitting procedure is derived which works for all simple exponential family distributions, including binomial, Poisson, and normal response variables. The procedure combines the selection of variables and the determination of the appropriate amount of smoothing. Penalized regression splines and the newly introduced penalized stumps are considered as weak learners. Estimates of standard deviations and stopping criteria, which are notorious problems in iterative procedures, are based on an approximate hat matrix. The method is shown to be a strong competitor to common procedures for the fitting of generalized additive models. In particular, in high-dimensional settings with many nuisance predictor variables it performs very well. [source] Extraction of Proteins from Biological Fluids by Use of an Ionic Liquid/Aqueous Two-Phase SystemCHEMISTRY - A EUROPEAN JOURNAL, Issue 7 2007Zhuo Du Abstract An ionic liquid/aqueous two-phase system based on the hydrophilic ionic liquid 1-butyl-3-methylimidazolium chloride (BmimCl) and K2HPO4 has been employed for direct extraction of proteins from human body fluids for the first time. Proteins present at low levels were quantitatively extracted into the BmimCl-rich upper phase with a distribution ratio of about 10 between the upper and lower phase and an enrichment factor of 5. Addition of an appropriate amount of K2HPO4 to the separated upper phase results in a further phase separation, giving rise to an improved enrichment factor of 20. FTIR and UV spectroscopy demonstrated that no chemical (bonding) interactions between the ionic liquid and the protein functional groups were identifiable, while no alterations of the natural properties of the proteins were observed. The partitioning of proteins in the two-phase system was assumed to have been facilitated by the electrostatic potential difference between the coexisting phases, as well as by salting out effects. The system could be applied successfully for the quantification of proteins in human urine after on-line phase separation in a flow system. The use of an ionic liquid, as a green solvent, offers clear advantages over traditional liquid,liquid extractions, in which the use of toxic organic solvents is unavoidable. [source] Longitudinal analysis when the experimenter does not determine when treatment ends: what is dose,response?CLINICAL PSYCHOLOGY AND PSYCHOTHERAPY (AN INTERNATIONAL JOURNAL OF THEORY & PRACTICE), Issue 6 2003Daniel J. Feaster The most appropriate amount of psychotherapy to address a particular problem is of interest to clinicians, consumers and those responsible for funding of care. The dose,response relationship has been examined within the context of randomized clinical trials, meta-analysis as well as naturalistic studies; however, each of these approaches has limits. Many of these approaches have conceptually blurred two distinct concepts: do participants with different characteristics need different amounts of therapy and do otherwise equal participants show different outcomes when given different levels of (a particular type of) therapy? For any study design, if the experimenter does not determine the duration of therapy, then the length of therapy is said to be endogenous. This endogeneity can bias any attempt to untangle the answer to these two questions. An extension of the biasing effect of this endogeneity involves the choice of times to assess outcome; if outcome assessment depends on when therapy is terminated (rather than exogenously chosen) then estimates of the trajectory of outcome may be biased. Design considerations to minimize this effect are discussed.,Copyright © 2003 John Wiley & Sons, Ltd. [source] Electrophosphorescent Polyfluorenes Containing Osmium Complexes in the Conjugated Backbone,ADVANCED FUNCTIONAL MATERIALS, Issue 9 2008Chen-Han Chien Abstract Electrophosphorescent copolymers have been synthesized by covalent bonding of a red-emitting osmium complex Os(bpftz), which contains two 3-trifluoromethyl-5-(4- tert -butyl-2-pyridyl)triazolate (bpftz) cyclometalated ligands, into the backbone of a bipolar polyfluorene (PF) copolymer. Employing these copolymers, a highly efficient red polymer light-emitting diode has been realised that has an external quantum efficiency of 18.0%, a maximum brightness of 38,000,cd,m,2, and an emission centered at 618,nm. In addition, after incorporating appropriate amounts of green-emitting benzothiadiazole (BT) and the aforementioned Os(bpftz) into the bipolar PF, an efficient white-light electroluminescent polymer is obtained that displays simultaneous blue, green, and red emissions. [source] Fabrication of Large-Area Silicon Nanowire p,n Junction Diode Arrays,ADVANCED MATERIALS, Issue 1 2004K. Q. Peng Large-area silicon nanowire p,n junction diode arrays (see Figure) have been fabricated by chemical etching of planar silicon p,n junction wafers in aqueous HF solution that contains appropriate amounts of silver nitrate near room temperature. The I,V characteristics have been measured using current-sensing atomic force microscopy, and nonlinear and rectifying electrical transport behavior has been observed. [source] Effects of nitrate-, ammonium-, and organic-nitrogen-based fertilizers on growth and yield of tomatoesJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 1 2005Anuschka Heeb Abstract Mineral and organic fertilizers contain different forms and amounts of nitrogen (N), which can affect yield and product quality. The aim of this study was to determine appropriate amounts of N applied as nitrate (NO), ammonium (NH), and organic N (a mixture based on chicken manure) for optimal growth and quality of tomatoes. A pot experiment with sand as substrate was established in a greenhouse with six-week-old tomato plants (Lycopersicon esculentum Mill. cv. "Armada"). Nitrogen was applied in nutrient solutions at different NO : NH ratios combined with different chloride levels (NO -dominated, NO = NH at low Cl,, NO = NH at high Cl,, and NH -dominated, respectively) or as organic N at four N-application rates (250, 500, 750, 1000 mg N plant,1 week,1). No significant differences in shoot biomass and yields of red tomatoes were observed between NO - or NH -fed plants. Nitrogen rates above 750 mg N plant,1 week,1 did not significantly increase marketable fruit yield, but enhanced shoot-biomass production. The NH -N-dominated treatments (which also had high Cl, concentrations) showed increasing incidence of blossom-end-rot (BER)-infected fruits. In the organic-N treatments, shoot-biomass production and yields were lower than in the inorganic-N treatments, but fruit quality was good with few BER-infected fruits. The results show that with a total N supply below 750 mg N plant,1 week,1, NH can be used as equivalent N source to NO, resulting in equivalent yields of marketable fruit under the conditions in this experiment. Einfluss von Nitrat, Ammonium und organischem Stickstoff auf Wachstum und Ertrag von Tomaten Mineralische und organische Dünger enthalten verschiedene Formen von und Mengen an Stickstoff (N), welche den Ernteertrag und die Produktqualität beeinflussen können. Das Ziel dieser Arbeit war es, geeignete N-Mengen , appliziert als Nitrat, Ammonium oder organischer Stickstoff , für optimales Wachstum und Qualität von Tomaten zu bestimmen. Dazu wurde mit sechs Wochen alten Tomatenpflanzen (Lycopersicon esculentum Mill. cv. "Armada") unter Gewächshausbedingungen mit Sand als Substrat ein Gefäßversuch angelegt. Die Applikation von N erfolgte in Form von Nährlösungen mit verschiedenen NO:NH -Verhältnissen, kombiniert mit unterschiedlichen Chlorid (Cl)-Konzentrationen (NO -dominiert, NO = NH bei niedrigem Cl,, NO = NH bei hohem Cl, und NH -dominiert) bzw. als organischer N. Jede dieser Behandlungen wurde mit vier verschiedenen N-Mengen angelegt (250, 500, 750, 1000 mg N Pflanze,1 Woche,1). Zwischen den mit Nitrat und Ammonium gedüngten Pflanzen konnte kein signifikanter Unterschied in Sprosswachstum und Ertrag an erntereifen Tomaten festgestellt werden. Stickstoffmengen über 750 mg N Pflanze,1 Woche,1 steigerten den Ertrag verkaufsfähiger Tomaten nicht signifikant, obwohl die Produktion an Sprossbiomasse noch anstieg. In den NH -dominiert gedüngten Gefäßen mit gleichzeitig hohen Cl-Konzentrationen in den Nährlösungen wurden häufiger Tomaten mit Blütenendfäule beobachtet. In den Behandlungen mit organischem Stickstoff waren die Sprossbiomasseproduktion und der Ertrag geringer als in den mineralisch gedüngten Behandlungen, aber die Qualität der Früchte war gut, mit nur wenigen durch Blütenendfäule geschädigten Tomaten. Die Ergebnisse zeigen, dass bei einer Stickstoffversorgung unter 750 mg N Pflanze,1 Woche,1 Ammonium anstelle von Nitrat verwendet werden kann. Im vorliegenden Versuch wurden unter diesen Bedingungen vergleichbare Erträge verkaufsfähiger Früchte erzielt. [source] Frontal free-radical copolymerization of urethane,acrylatesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 9 2006Ting Hu Abstract We report the first synthesis of urethane,acrylate copolymers via free-radical frontal polymerization. In a typical run, the appropriate amounts of the reactants (urethane,acrylate macromonomer and 2-hydroxyethyl acrylate) and initiator (ammonium persulfate) were dissolved in dimethyl sulfoxide. Frontal polymerization was initiated by the heating of the wall of the tube with a soldering iron, and the resultant hot fronts were allowed to self-propagate throughout the reaction vessel. Once it was initiated, no further energy was required for the polymerization to occur. The dependence of the front velocity and front temperature on the initiator concentration was investigated. The front temperatures were between 55 and 65 °C, depending on the persulfate concentration. Thermogravimetric analysis indicated that the urethane,acrylate copolymers had higher thermal stability than pure frontally prepared polyurethane. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3018,3024, 2006 [source] Clinical use of physical activity measuresJOURNAL OF THE AMERICAN ACADEMY OF NURSE PRACTITIONERS, Issue 2 2009CRNP (Associate Professor), Lorraine M Reiser PhD Abstract Purpose:, To provide a review of physical activity measures and subjective and objective methods of its measurement. Considerations for the use of these measurements in research and practice will be discussed. Data sources:, The PubMed, CINAHL, and Health and Psychosocial Instruments databases, and the Centers for Disease Control Web site were searched using the search term "Physical Activity Measurement." Conclusions:, Physical activity is a lifestyle factor that is a key focus in chronic disease,related research, prevention, and interventions. Healthy People 2010 set goals of decreasing the prevalence of preventable diseases by encouraging healthier lifestyle patterns. Shifts toward more sedentary lifestyles have resulted in increases in life-limiting disease states, including obesity, diabetes, heart disease, cancer, and osteoporosis. Physical activity measurements have been used widely in research studies but are less commonly used in primary care. Measuring individuals' physical activity levels as part of the health assessment will enhance the provider's ability to engage in health promotion and suggest health protection interventions. The strengths, weaknesses, and potential applications to practice of physical activity measures are summarized in an effort to familiarize nurse practitioners (NPs) with commonly used tools and encourage integration of physical activity assessment into their current practice. Implications for practice:, NPs are in an ideal position to promote health by encouraging appropriate amounts of physical activity. Screening, health promotion, and disease prevention are part of the core competencies of NP practice established by the National Organization of Nurse Practitioner Faculties. Increased knowledge of physical activity measures will enhance the NP's ability to evaluate relevant physical activity research for use in evidence-based practice. Incorporation of simple yet appropriate physical activity measurements into practice will expand the NP's ability to identify and thus address sedentary lifestyles in their clientele. [source] Single-Calcination Synthesis of Pyrochlore-Free 0.9Pb(Mg1/3Nb2/3)O3,0.1PbTiO3 and Pb(Mg1/3Nb2/3)O3 Ceramics Using a Coating MethodJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 2 2003Huiming Gu A coating approach for synthesizing 0.9Pb(Mg1/3Nb2/3)O3,0.1PbTiO3 (0.9PMN,0.1PT) and PMN using a single calcination step was demonstrated. The pyrochlore phase was prevented by coating Mg(OH)2 on Nb2O5 particles. Coating of Mg(OH)2 on Nb2O5 was done by precipitating Mg(OH)2 in an aqueous Nb2O5 suspension at pH 10. The coating was confirmed using optical micrographs and zeta-potential measurements. A single calcination treatment of the Mg(OH)2 -coated Nb2O5 particles mixed with appropriate amounts of PbO and PbTiO3 powders at 900°C for 2 h produced pyrochlore-free perovskite 0.9PMN,0.1PT and PMN powders. The elimination of the pyrochlore phase was attributed to the separation of PbO and Nb2O5 by the Mg(OH)2 coating. The Mg(OH)2 coating on the Nb2O5 improved the mixing of Mg(OH)2 and Nb2O5 and decreased the temperature for complete columbite conversion to ,850°C. The pyrochlore-free perovskite 0.9PMN,0.1PT powders were sintered to 97% density at 1150°C. The sintered 0.9PMN,0.1PT ceramics exhibited a dielectric constant maximum of ,24 660 at 45°C at a frequency of 1 kHz. [source] Determination of residues of endosulfan in human blood by a negative ion chemical ionization gas chromatographic/mass spectrometric method: impact of long-term aerial spray exposurePEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 3 2003Atmakuru Ramesh Abstract A new and sensitive analytical method using negative ion chemical ionization gas chromatography/mass spectrometry in selective ion monitoring (SIM) mode has been developed for the determination of residues of endosulfan in the human blood. The residues of endosulfan are extracted from whole blood samples without separating the serum by the addition of 60% sulfuric acid at 10,°C followed by partition with hexane,+,acetone (9,+,1 by volume). The total endosulfan is quantified as the sum of alpha-endosulfan, beta-endosulfan and endosulfan sulfate in SIM mode. The mass-fragment ions used for this purpose that are monitored for in SIM mode include endosulfan diol: 95, 169, 214, 313, alpha-endosulfan: 99, 242, 270, 406, beta-endosulfan: 99, 242, 270, 406, and endosulfan sulfate: 97, 353, 386. Recovery experiments were conducted at the concentration range 1.0,100,pg,ml,1. Results showed 112,98% recovery of total endosulfan from the whole blood samples. The relative standard deviation was 1.49,2.68%. The method was found to be highly sensitive in quantifying endosulfan residues down to the 0.1,pg,ml,1 level. Conversion of endosulfan to endosulfan diol was found to be less than 0.1% under the conditions used. The results were compared with published data. The applications of the analytical method for the determination of endosulfan residues in real samples was tested by analyzing 106 human blood samples collected from a population living in Padre village, Kasargode District, Kerala, India, where aerial spraying of endosulfan has been a common agricultural practice over the years. The results showed that none of the blood samples contained residues of endosulfan (alpha-endosulfan,+,beta-endosulfan,+,endosulfan sulfate) or endosulfan diol. The results were confirmed by the detection of the appropriate amounts in a number of these samples which had subsequently been spiked with endosulfan. © 2003 Society of Chemical Industry [source] Using Screen-Based Simulation to Improve Performance During Pediatric ResuscitationACADEMIC EMERGENCY MEDICINE, Issue 2009Kevin J. Biese MD Abstract Objectives:, To assess the ability of a screen-based simulation-training program to improve emergency medicine and pediatric resident performance in critical pediatric resuscitation knowledge, confidence, and skills. Methods:, A pre,post, interventional design was used. Three measures of performance were created and assessed before and after intervention: a written pre-course knowledge examination, a self,efficacy confidence score, and a skills-based high-fidelity simulation code scenario. For the high-fidelity skills assessment, independent physician raters recorded and reviewed subject performance. The intervention consisted of eight screen-based pediatric resuscitation scenarios that subjects had 4 weeks to complete. Upon completion of the scenarios, all three measures were repeated. For the confidence assessment, summary pre- and post-test summary confidence scores were compared using a t-test, and for the skills assessment, pre-scores were compared with post-test measures for each individual using McNemar's chi-square test for paired samples. Results:, Twenty-six of 35 (71.3%) enrolled subjects completed the institutional review board,approved study. Increases were observed in written test scores, confidence, and some critical interventions in high-fidelity simulation. The mean improvement in cumulative confidence scores for all residents was 10.1 (SD ±4.9; range 0,19; p < 0.001), with no resident feeling less confident after the intervention. Although overall performance in simulated codes did not change significantly, with average scores of 6.65 (±1.76) to 7.04 (±1.37) out of 9 possible points (p = 0.58), improvement was seen in the administering of appropriate amounts of IV fluids (59,89%, p = 0.03). Conclusions:, In this study, improvements in resident knowledge, confidence, and performance of certain skills in simulated pediatric cardiac arrest scenarios suggest that screen-based simulations may be an effective way to enhance resuscitation skills of pediatric providers. These results should be confirmed using a randomized design with an appropriate control group. [source] Key worker services for disabled children: what characteristics of services lead to better outcomes for children and families?CHILD: CARE, HEALTH AND DEVELOPMENT, Issue 2 2006P. Sloper Abstract Background, Research has shown that families of disabled children who have a key worker benefit from this service and recent policy initiatives emphasize the importance of such services. However, research is lacking on which characteristics of key worker schemes for disabled children are related to better outcomes for families. Methods, A postal questionnaire was completed by 189 parents with disabled children who were receiving a service in seven key worker schemes in England and Wales. Path analysis was used to investigate associations between characteristics of the services and outcomes for families (satisfaction with the service, impact of key worker on quality of life, parent unmet need, child unmet need). Results, The four path models showed that key workers carrying out more aspects of the key worker role, appropriate amounts of contact with key workers, regular training, supervision and peer support for key workers, and having a dedicated service manager and a clear job description for key workers were associated with better outcomes for families. Characteristics of services had only a small impact on child unmet need, suggesting that other aspects of services were affecting child unmet need. Conclusions, Implications for policy and practice are discussed, including the need for regular training, supervision and peer support for key workers and negotiated time and resources for them to carry out the role. These influence the extent to which key workers carry out all aspects of the key worker's role and their amount of contact with families, which in turn impact on outcomes. [source] | |||||||||||||||||||||||||||||||||||||