Results 1 - 10 of 298
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[en] ESR spectroscopy and nanosecond pulse radiolysis have been used to study the species formed in single crystals of NaND4-tartrate on irradiation. The primary reduction product -OOCCHODCHODCOOD- has an optical absorption maximum at 400 nm. It decays at +21degC with a half life of 2.2 μs to -OOCCHODCHCOO-. The activation energy for the anionic decay is 8.3 kcal mol -1. The primary oxidation product [-OOCCHODCHODCOO-]+ decays by decarboxylation to -OOCCHODCHOD. On further heating all secondary radicals are transformed to -OOCCHODCODCOO-, which is stable at room temperature. (author)
[en] A new formulation of a freeze-dried kit for the labeling of tetrofosmin with technetium-99m has been developed. The kit contains lyophilized mixture of 0.320 mg tetrofosmin [6,9-bis(2-ethoxyethyl)-3,12-dioxa- 6,9-diphosphatetradecane], 0.025 mg stannous chloride dihydrate, 5 mg sodium tartrate and 5 mg sodium hydrogen carbonate. The product contains no antimicrobial preservative. When 99mTc pertechnetate up to 6 mL saline containing 200 mCi is added to lyophilized mixture, a lipophilic, cationic 99mTc complex is formed, 99mTc-tetrofosmin. The performance of newly developed kit is compared with commercially available MYOVIEW kit for heart imaging. The patient studies show that the images of heart obtained by 99mTc-tetrofosmin prepared by new formulation are equally good to MYOVIEW. (author)
[en] The solubility of (1R,2R)-(+)-1,2-diaminocyclohexane L-tartrate (DHT) in methanol + water, ethanol + water, and 2-propanol + water mixed solvents were measured using a synthetic method with alcohols mass fractions varying from 0.1 to 0.5 over 278.15 to 318.15 K under atmospheric pressure (P = 0.1 MPa). It was proved that the solubility of DHT in the three binary solvents increased with increasing temperature, while decreased with the mass fraction of alcohols rising. The experimental solubility data were correlated by the modified Apelblat equation and Sun model. The modified Apelblat model showed better agreement with the experimental data than the other model. Furthermore, the thermodynamic parameters including , , and for DHT in the dissolution process were obtained from Van’t Hoff plots.
[en] Alkaline phosphatase (ALP), tartrate-resistant acid phosphatase (TRAP) and aspartate aminotransferase (AST) activities were studied as bio markers of canine movement. Root resorption was also evaluated in canines subjected to the orthodontic forces. Nineteen subjects randomly received 100 and 150 g force using self-ligating brackets (SLB) either on the right or left site of maxillary arch. Gingival crevicular fluid samples were collected at distal sites of canines for five consecutive weeks. The activities of ALP, TRAP and AST were assayed and measured spectrophotometrically. Canine movement was measured for five consecutive weeks while root resorption was monitored at baseline, week 0 and week 5 using periapical radiographs. In 100 g group, TRAP activity significantly increased in week 3-5 when compared to TRAP baseline activity. However, ALP and AST activities slightly increased. In 150 g group, ALP and TRAP activities slightly increased when compared with their baseline activities. However, AST significantly increased in week 5. Canine movement and root resorption were not significantly different (p<0.05) in both groups. A force of 100 and 150 g slightly increased the bone modeling process and resulted in similar canine movement and root resorption. Therefore, 100 g force could be an optimum force for canine retraction and is preferable (compared with 150 g force) in canine retraction using SLB. (author)
[en] An integrated photocatalyst was prepared and its photoelectrocatalytic behavior for solar energy conversion was investigated. To make an integrated photocatalyst for hydrogen evolution, Pt and CdS clusters were embedded in zeolite as a cocatalyst and a photocatalyst, respectively. Pt particles were embedded in zeolite Y by ion exchange reaction with Pt (NH3)42+ and activation and reduction processes were followed. CdS clusters in zeolite Y cages were prepared by ions exchange reaction with Cd2+ and sulfurization with Na2S in aqueous solution was followed. The existence of CdS clusters in the cavities of zeolite Y was detected by IR spectra. UV absorption edged of the samples prepared show blue shifts about 0.03-0.12 eV from the edge of bulk CdS, which is an indication of CdS clusters formed in zeolite Y. The pore structure of samples was analyzed by BET and Langmuir method. The solar energy conversion into hydrogen was investigated, where sodium tartrate solution was used as a hole scavenger. We could observe that 1 wt% Pt supported sample was the most effective photocatalyst for hydrogen evolution (62 μL/mg after 4 hour reaction)
[en] A spectrophotometric method was developed for the determination tolterodine tartrate. The method is based on the formation of intensely colored charge-transfer complexes formed by the interaction of this drug as n-electron donors with Para-chloranilic acid (p-CA) and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as the pie-acceptors. The colored complexes exhibit maximum absorption at 500 and 460 nm respectively. Beer's law is obeyed in the concentration ranges 20-380 and 18-230 microg/ml using (p-CA) and (DDQ) respectively and the limits of detection and quantification are reported. The proposed method was applied to the determination of the drug in pharmaceutical formulations and the results demonstrated that the method is equally accurate, precise and reproducible as the official methods. The validity of method was established by recovery studies with satisfactory results. (author)
[en] Adsorption of Pb"2"+ ion by a tartrate intercalated MgAl layered double hydroxides (MgAl-TA LDHs) was studied. The adsorption isotherms and kinetics were investigated as a function of various experimental parameters using batch adsorption experiments. The results indicated that the adsorption isotherm was well described by Sips model. The kinetic adsorption data were fitted well to the pseudo-second-order kinetic equation. The adsorption of Pb"2"+ was controlled mainly by the chemical process combined with intraparticle diffusion. Parameters of adsorption thermodynamic suggested that the interaction of Pb"2"+ adsorbed by MgAl-TA LDHs adsorbents was thermodynamically spontaneous and endothermic.