Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.1.2.42 (DTA)
 1,693 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report here the synthesis of Ce(x)Zr(1-x)O(2) and (Ce(0.7)Zr(0.3)O(2))(x)(Al(2)O(3))(1-x) core-shell nanopowders in a single step by liquid-feed flame spray pyrolysis (LF-FSP) of the metalloorganic precursors, Ce(O(2)CCH(2)CH(3))(3)(OH), alumatrane [N(CH(2)CH(2)O)(3)Al], and Zr(O(2)CCH(2)CH(3))(2)(OH)(2). Solutions of all three precursors in ethanol with ceramic yields of 2.5 wt% were aerosolized with O(2), combusted at temperatures above 1500 degrees C, and rapidly quenched at approximately 1000 degrees C/ms to form Ce(x)Zr(1-x)O(2) and (Ce(0.7)Zr(0.3)O(2))(x)(Al(2)O(3))(1-x) nanopowders of selected compositions, at rates of 50-100 g/h. The resulting, as-processed, materials are unaggregated nanopowders with average particle sizes (APSs) < 20 nm and corresponding specific surface areas of 30-50 m(2)/g. The as-processed powders were characterized in terms of phase, particle size, specific surface area, compositions, and morphology by XRD, BET, DLS, SEM, TEM, XPS, TGA-DTA, and FT-IR. LF-FSP provides access to binary Ce(x)Zr(1-x)O(2) nanopowders and ternary (Ce(0.7)Zr(0.3)O(2))(x)(Al(2)O(3))(1-x) nanopowders in one step. The obtained Ce(0.7)Zr(0.3)O(2) powders are solid solutions with a cubic phase. In contrast, LF-FSP of mixtures of the three precursors at specific compositions [x = 0.5, 0.7 for (Ce(0.7)Zr(0.3)O(2))(x)@(Al(2)O(3))(1-x)] provide core-shell nanopowders in a single step. The most reasonable explanation is that there are differences in the rates of condensation, nucleation and miscibility between the gas phase ions that form the Ce(x)Zr(1-x)O(2) solid solutions and those that condense to delta-Al(2)O(3) during processing. These as-produced materials are without microporosity at surface areas of > or = 30 m(2)/g. Evidence is presented suggesting the formation of (Ce/Zr)(3+) species in the as-processed (Ce(0.7)Zr(0.3)O(2))(x)(Al(2)O(3))(1-x) core-shell materials. An accompanying paper indicates that these materials offer significant and novel catalytic activities for hydrocarbon oxidation and deNO(x) processes without using platinum as a co-catalyst.
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PMID:One-step synthesis of core-shell (Ce0.7Zr0.3O2)(x)(Al2O3)(1-x) [(Ce0.7Zr0.3O2)@Al2O3] nanopowders via liquid-feed flame spray pyrolysis (LF-FSP). 1956 96

(99m)Tc can be produced from (99)Mo/(99m)Tc gel generators. These gels are part of the generator and the (99)Mo/(99m)Tc gel generator performance is directly related with gel structure. In this work a series of zirconium molybdate gels have been synthesized and dried under different conditions and characterized using thermal analysis (TGA, DTA), SEM, XRD and porosity measurements. It is found that the water content of the gel determines the structure porosity which allows the diffusion of the (99m)TcO(4)(-) ions inside the gel and was directly connected with performance of the (99)Mo/(99m)Tc gel generators. Drying conditions of the gel is as an important factor that influence water content and physical-chemical properties of this gel and must be carefully studied to optimize the properties of the gel generators.
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PMID:Influence of drying conditions of zirconium molybdate gel on performance of (99m)Tc gel generator. 1964 Jul 23

ZrO(2) supported La(2)O(3) catalyst prepared by impregnation method was examined in the transesterification reaction of sunflower oil with methanol to produce biodiesel. It was found that the catalyst with 21 wt% loaded La(2)O(3) and calcined at 600 degrees C showed the optimum activity. The basic property of the catalyst was studied by CO(2)-TPD, and the results showed that the fatty acid methyl ester (FAME) yield was related to their basicity. The catalyst was also characterized by TG-DTA, XRD, FTIR, SEM and TEM, and the mechanism for the formation of basic sites was discussed. It was also found that the crystallite size of support ZrO(2) decreased by loading of La(2)O(3), and the model of the solid-state reaction on the surface of La(2)O(3)/ZrO(2) catalyst was proposed. Besides, the influence of various reaction variables on the conversion was investigated.
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PMID:Transesterification of sunflower oil to biodiesel on ZrO2 supported La2O3 catalyst. 1976 83

Circulating fluidized bed combustion (CFBC) bottom ashes (CBAs) are a class of calcined aluminosilicate wastes with a unique thermal history. While landfill disposal of hazardous element-containing CBAs poses serious challenge, these wastes have long been neglected as source materials for geopolymer production. In this paper, geopolymerization of ground CBAs was investigated. Reactivity of the CBAs was analyzed by respective dissolution of the ashes in 2, 5, and 10N NaOH and KOH solutions. Geopolymer pastes were prepared by activating the CBAs by a series of alkalis hydroxides and/or sodium silicate solutions. Samples were cured at 40 degrees C for 168 h, giving a highest compressive strength of 52.9 MPa. Of the optimal specimen, characterization was conducted by TG-DTA, SEM, XRD, as well as FTIR analyses, and thermal stability was determined in terms of compressive strength evolution via exposure to 800 or 1050 degrees C followed by three cooling regimes, i.e. cooling in air, cooling in the furnace, and immerging in water. The results show that CBAs could serve as favorable source materials for thermostable geopolymers, which hold a promise to replace ordinary Portland cement (OPC) and organic polymers in a variety of applications, especially where fire hazards are of great concern.
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PMID:Synthesis of thermostable geopolymer from circulating fluidized bed combustion (CFBC) bottom ashes. 1987 90

Ta2O5 nanopowders to be used as sensing electrodes in high temperature electrochemical gas sensors for hydrocarbons detection were synthesized using a sol-gel method and their structural and microstructural properties were investigated. The as-synthesized powders were heated at different temperatures in the range 250-1000 degrees C and characterized by TG-DTA, XRD, SEM, TEM and FT-IR. This investigation allowed to identify the correct thermal treatments to achieve the microstructural, textural and functional stability of materials working at high temperature, preserving their nano-metric grain size. Planar sensors fabricated by using Ta2O5 powders treated at 750 degrees C showed promising results for the selective detection of propylene at high temperature (700 degrees C). The good stability of the sensing response after gas exposure at high temperature was correlated to the stable microstructure the electrodes. Thus, Ta2O5 powders seems good candidate as sensing electrode for sensors for automotive exhausts monitoring.
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PMID:Tailoring the structural and microstructural properties of nanosized tantalum oxide for high temperature electrochemical gas sensors. 1991 69

Y(2)O(3):Eu(3+) nano-powders were synthesized by homogeneous precipitation and the influence of solution acidity was investigated. IR and TG-DTA analysis showed that in different acidic solutions different kinds of sediments were generated. TEM images revealed distinct morphologies of obtained powders. The resultant powders were sintered into ceramics in vacuum and then in N(2) atmosphere without any additives. SEM images indicated that the morphologies of powders have significant impact on the microstructures of sintering-derived ceramics. Low-agglomerated and uniform powders were in favor of production of ceramics with homogeneous microstructures. Excitation and emission spectra of both powders and ceramics were measured and some changes were observed.
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PMID:Effect of acidity on microstructure and spectroscopic properties of Y2O3:Eu3+ powders and ceramics. 2000 9

The accelerated carbonation of high Ca content Municipal Solid Waste Incineration (MSWI) fly ash was investigated with an L:S ratio of 0.25:1 to study the effect of accelerated carbonation on the leaching of critical heavy metals (As, Cd, Cu, Zn, Sb, Pb) in the fly ash. The results of XRD analysis showed after carbonation the peaks of Ca(OH)2 and CaClOH disappeared, while the peaks of CaCO3 became intense. After carbonation, the mineral phase of Pb was changed and Cu compound (CuTi2.05S4) was identified. The TG/DTA analysis showed the weight gain of the fly ash before 440 degrees C reached 5.70%. Furthermore, the SEM-EDS analysis confirmed the occurrence of the reaction of Ca(OH)2 (s) + CO2 (g) --> CaCO3 (s). The TCLP test of carbonated fly ash revealed that the leaching concentration of the critical heavy metals, except Cd, decreased within the carbonation time of 2 h. When the carbonation time was longer than 50 h, the leaching concentration of critical heavy metals, except Ph were higher than that of un-carbonated fly ash.
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PMID:[Accelerated carbonation of high Ca content municipal solid waste incineration fly ash and impact on leaching of heavy metal]. 2006 61

Poly-o-anisidine Sn(IV) arsenophosphate is a newly synthesized nanocomposite material and has been characterized on the basis of its chemical composition, ion exchange capacity, TGA-DTA, FTIR, X-RAY, SEM, and TEM studies. On the basis of distribution studies, the exchanger was found to be highly selective for lead that is an environmental pollutant. For the detection of lead in water a heterogeneous precipitate based ion-selective membrane electrode was developed by means of this composite cation exchanger as electroactive material. The membrane electrode is mechanically stable, with a quick response time, and can be operated over a wide pH range. The selectivity coefficients were determined by mixed solution method and revealed that the electrode is sensitive for Pb(II) in presence of interfering cations. The practical utility of this membrane electrode has been established by employing it as an indicator electrode in the potentiometric titration of Pb(II).
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PMID:Synthesis and Characterization of Organic-Inorganic Nanocomposite Poly-o-anisidine Sn(IV) Arsenophosphate: Its Analytical Applications as Pb(II) Ion-Selective Membrane Electrode. 2014 82

The implantation of controlled drug release devices represents a new strategy in the treatment of neurodegenerative disorders. Sol-gel titania implants filled with valproic acid, have been used for this purpose to treat induced epilepsy in rats. The kinetics of the drug release depend on: (a) porosity, (b) chemical interactions between valproic acid and surface hydroxyl groups of titania, (c) particle size, and (d) particle size agglomerates. The concentration of water used in the hydrolysis reaction is an important variable in the degree of porosity, hydroxylation, and structural defects of the nanostructured titanium oxide reservoir. The titanium n-butoxide/water ratio was systematically varied during the sol-gel synthesis, while maintaining the amount of valproic acid constant. Characterization studies were performed using DTA-TGA, FTIR, Raman, TEM, SEM, BET, and in vitro release kinetic measurements. The particle agglomerate size and porosity were found to depend on the amount of water used in the sol-gel reaction.
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PMID:The effect of water on particle size, porosity and the rate of drug release from implanted titania reservoirs. 2018 18

In this paper, a new kind of polymeric nanocomposite materials based on nano-hydroxyapatite (n-HA) and PCL-Pluronic-PCL (PCFC) copolymer were prepared by in situ combination method. Firstly, the PCFC copolymer was synthesized by ring-opening polymerization of epsilon-caprolactone initiated by Pluronic (PEG-PPG-PEG); Secondly, n-HA powder were combined with PCFC to form polymeric composites in the presence of hexamethylene diisocyanate (HDI). The obtained composites were characterized by 1H-NMR, FTIR, XRD, TEM, SEM, DTA/TGA, and tensile testing. The results revealed that n-HA could be dispersed into polymer matrix uniformly, and the n-HA/PCFC composite showed great mechanical properties when the content of n-HA was 10 wt%. The microstructure and thermal properties of the composites were discussed in the paper too. The experimental results suggested that this polymeric nanocomposite might have great potential application in the field of tissue engineering.
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PMID:Preparation and characterization of n-hydroxyapatite/PCL-pluronic-PCL nanocomposites for tissue engineering. 2035 8


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