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Abstract  

Sediment core samples were collected from Hiroshima Bay in the Seto Inland Sea, western Northwest Pacific Ocean, and their 239+240Pu activities and 240Pu/239Pu atom ratios were determined by sector field ICP-MS. The activities of 239+240Pu ranged from 0.556 ± 0.025 to 0.745 ± 0.023 mBq/g. The atom ratios of 240Pu/239Pu were almost constant within the whole depth; the average value was 0.227 ± 0.014. This atom ratio was significantly higher than the mean global fallout ratio of 0.18, proving the presence of close-in fallout Pu that originated from the Pacific Proving Ground (PPG). The water masses exchanges between the Kuroshio Current and the Seto Inland Sea brought the PPG source Pu to this area, then Pu was extensively scavenged into sediment particles supplied by the rivers around the bay. The relative contributions of the global fallout Pu and the PPG close-in fallout Pu were evaluated by the two end-member mixing model. The contribution of the PPG close-in fallout was 38–41% of the total Pu in sediment. The remaining 59–62% was attributed to direct global fallout and the land-origin Pu transported by the rivers around the Hiroshima Bay.

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Abstract  

To investigate the radio impurity in the radiolysis of 18F-FDG at high radiodose and radioconcentrated solutions and develop methods of repurification. The radiolysis of 18F-FDG was analyzed by TLC. The radio-impurity was confirmed by biodistribution and small animal PET/CT studies. 18F-FDG was unstable at high radioconcentrition over 37 GBq/mL or under basic condition. TLC, biodistribution and PET/CT all indicated that the main autoradiolysis byproduct was free fluoride ion. The radiolyzed 18F-FDG was repurified by solid-phase extraction (SPE) column. The repurified 18F-FDG had a radiochemical purity (RCP) of over 99% and significantly lower bone uptake than that was before repurification (P = 0.0003). There was a positive correlation between the recovery yield and the purity of 18F-FDG (R 2 = 0.66).

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JPC - Journal of Planar Chromatography - Modern TLC
Authors:
Kunbo Wang
,
Zhonghua Liu
,
Jian-an Huang
,
Donghe Fu
,
Fang Liu
,
Yushun Gong
, and
Xiaosong Wu

The potential of polyamide as adsorbent for separation of nine compounds — (±)-catechin (DL-C), (−)-epicatechin (EC), (−)-epigallocatechin (EGC), (−)-epicatechin gallate (ECg), (−)-epigallocatechin gallate (EGCg), theaflavin (TF1), theaflavin 3-gallate (TF2A), theaflavin 3′-gallate (TF2B), and theaflavin 3,3′-digallate (TF3) — was studied. Polyamide TLC plates dried with a hair dryer, application as bands, and development in a horizontal chamber gave the best results. Detection was performed using iron(III) chloride-ethanol reagent. Twofold development with chloroform-methanol 2:3 ( v/v ) as mobile phase resulted in the separation of TF1, TF2A, TF2B, and TF3 from all the other compounds. EGCg, ECg, and EGC were separated but EC and DL-C were not separated from each other. The best mobile phase for each of the compounds is reported. The best separation of the five main catechins (EC, DL-C, EGC, ECg, and EGCg) was achieved by use of n -butanol-acetone-acetic acid 5:5:3 ( v/v ). In addition, separation of the flavonols myricetin, quercetin, kaempferol, and rutin and the phenolic acids gallic acid, chlorogenic acid, and caffeic acid was achieved by twofold development with chloroform-methanol 2:3 ( v/v ). The applicability of the method was checked by screening of extracts of green, black, oolong, and pu-erh tea.

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Abstract

The decomposition reaction process of waste rare earth (RE) polishing powder was monitored in real time by the thermogravimetry–differential thermal analysis (TG–DTA) and Fourier transform infrared spectroscopy (FTIR). The results showed that the reaction was divided into two stages, and the thermal weight losses got to stable when the temperature was more than 400 °C. The releasing gas mainly contained H2O and SiF4, and the reaction kinetics during decomposition process was studied by the methods of Freeman-Carroll and Kissinger.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
Shuye Yang
,
Xuebin Wang
,
Haixun Guo
,
Jian Liu
,
Fenglong Wang
, and
Xianzhong Zhang

Abstract  

Mixed ligand fac-tricarbonyl complex of [99mTc(CO)3-DMSA-MIBI] has been prepared starting from the precursor [99mTc(OH2)3(CO)3]+. The complex can be obtained in good yield and purity in a two-step procedure by first attaching meso-2,3-dimercaptosuccinic acid (DMSA, HOOCCH(SH)CH(SH)COOH) with [99mTc(OH2)3(CO)3]+, followed by addition of MIBI [tetrakis-2-methoxyisobutylisonitrile (CH3OC(CH3)2CH2-N≡C) copper(I) tetrafluoroborate] solution. The complex was characterized by TLC and HPLC and was studied by means of octanol-water partition coefficient, electrophoresis, stability in vitro, and normal mice experiment. Biodistribution in mice demonstrated that the complex showed higher myocardial uptake after 0.5-hour p.i. The ratios of heart/liver (%ID/g) in the case of 99mTc(CO)3-DMSA-MIBI was higher (1.88) than that observed in case of 99mTc-MIBI1 (0.93) after 0.5-hour p.i. (P<0.05). Results showed that the complex may be developed to a novel myocardial perfusion-imaging agent.

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Abstract

The hydrogenation of biomass-derived ethyl lactate was studied over several ruthenium catalysts (Ru/TiO2, Ru/SiO2, Ru/γ-Al2O3, Ru/NaY and Ru/C), with the intent of developing a simple and additive-free catalytic system. The catalytic performance is dependent on the nature of the support. Ru/SiO2 was found to be an efficient catalyst for the hydrogenation of ethyl lactate to 1,2-propanediol (1,2-PDO). Parametric studies show that the reaction temperature, hydrogen pressure and catalyst amount can significantly influence the catalytic performance. Under optimal reaction conditions (433 K, 5 MPa), high yield of 1,2-PDO (82.1%) was obtained without the introduction of any additives. Form a practical point of view, this study may open the way to a new approach for the production of 1,2-PDO.

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The oxidation of cyclohexane to cyclohexanone, cyclohexanol, and adipic acid, which are important raw materials in nylon industry, is still being challenged in conventional processes. Microreactors and gold catalysts are both widely researched areas at present, so an effort was made to make use of collaborative properties of both. In this study, stainless steel microcapillary coated with a supported nano-gold catalyst was prepared, characterized, and employed for the oxidation of cyclohexane. Under the temperature of 180 °C, residence time of 4 min, reaction pressure of 3 MPa and molar ratio of oxygen to cyclohexane of 0.3:1, the conversion of cyclohexane was 2.09%, with the selectivity of cyclohexanol, 29.37%; cyclohexanone, 39.89%; cyclohexyl hydroperoxide, 2.46%; and adipic acid, 18.87%. Experiments showed that stainless steel microcapillary coated with a supported nano-gold catalyst in cyclohexane oxidation is a feasible process; the reaction time is very short, and the process operation runs safely.

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Abstract  

The i-butyldodecylsulfoxide (BDSO) was synthesized. The extraction of uranium(VI) has been carried out with BDSO in toluene from various HNO3 concentrations. It was found that the distribution ratio increases with increasing nitric acid concentration up to 3.0 mol/l and then decreases. The distribution ratios also increase with increasing extractant concentration. The extracted species appears to be UO2(NO3)2·2BDSO and the equilibrium constant value is 15.2. The influence of temperature, sodium nitrate and oxalate concentrations on the extraction was also investigated, and the thermodynamic functions of the extraction reaction were obtained.

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Abstract  

The kinetics and mechanism of uranium(VI) extraction from nitric acid solution by bis(octylsulfinyl)methane (BOSM) are studied with the method of stationary interface cell. The effects of temperature, extractant and nitric acid concentrations are discussed. The results showed that the extraction process is controlled by the following reaction: UO2(NO3)2 + BOSM(i)k1 k-1UO2(NO3)2BOSM(i). The variation of enthalpy associated with the extraction is -22.1±2.1 kJ/mol.

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Abstract

TiO2–SiO2 catalysts for glycerol acetalization with acetone are synthesized by the sol–gel method and characterized by N2 adsorption–desorption, X-ray diffraction, NH3-temperature programmed desorption, Fourier transform infrared spectroscopy and ultraviolet–visible diffuse reflectance spectroscopy techniques in the present work. The effects of catalyst preparation and acetalization parameters such as reaction time, acetone/glycerol ratio, catalyst amount and reaction temperature on acetalization are investigated simultaneously. Pyridine adsorption results indicate that Ti–Si mixed oxides naturally only consist of Lewis acidic sites. The results of catalyst preparation and characterization show that Br⊘nsted acidic sites can be produced after Ti–Si mixed oxides adsorb water molecules, and TiO2–SiO2 (Si/Ti = 1) calcined at 550 °C exhibits the most total acidic density leading to the highest catalytic property in glycerol acetalization. The glycerol catalytic acetalization mainly occurs on the Br⊘nsted acidic sites. The effects of acetalization parameters indicate that the formation of the main product 5-membered ring ketal 2,2-dimethyl-1,3-dioxolane-4-yl methanol (about 90 %) is governed by kinetics. About 95 % glycerol conversion in acetalization is obtained under the optimum conditions.

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