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[en] Concentration of [18F]fluoride has been mentioned in literature, however, reports have lacked details about system designs, operation, and performance. Here, we describe in detail a compact, fast, fully-automated concentration system based on a micro-sized strong anion exchange cartridge. The concentration of radionuclides enables scaled-up microfluidic synthesis. Our system can also be used to provide highly concentrated [18F]fluoride with minimal water content. We demonstrate how the concentrator can produce varying concentrations of [18F]fluoride for the macroscale synthesis of N-boc-5-[18F]fluoroindole without an azeotropic drying process, while enabling high starting radioactivity. By appropriate choice of solid-phase resin, flow conditions, and eluent solution, we believe this approach can be extended beyond [18F]fluoride to other radionuclides.
[en] Two levels metalloid impurity elements reference material in uranium concentrate were developed. The reference materials can be used for the trace measuring value and its transfer of metalloid impurity elements, manufacturing environment of reference materials was in accordance with the technical specification of national class A standard substance. (authors)
[en] In this project we have researched and evaluated the separation possibility of uranium ore in Palua area. Although scale and expenses of the project are limited, we have carried out this project during a year and had some reliable results. Uranium ore in Palua area which has concentrate of 440 ppm was separated into two main ingredients containing uranium concentrate more than 550 ppm and less than 190 ppm. (author)
[en] A analysis method for determination of sulphuric acid radical in diuranate by barium sulfate nephelometery was studied. The experimental results show that the linear correlation coefficient (r) > 0.997 when concentration of sulphuric acid radical was in the range of 16 to 40 μg/mL. The detection limit of the method was 0.4% when sample quantity was 0.5 g, and the recovery was in the range of 90.7% to 105%. RSD was 2.8% when concentration of sulphuric acid radical was 5.72%. 0.4 mg of fluorin and 10 mg of calcium did not interfere with determination of sulphuric acid radical. (authors)
[en] Highlights: • A simple, low-cost, and sensitive liposome-based colorimetric aptasensor has been developed to detect OTA. • The strategy combines advantages of the signal amplification of liposome and the high specificity and low cost of aptamer. • The signal amplification via HRP-encapsulated lipsomes can be achieved in one step without additional surfactant. • The proposed colorimetric aptasensor has been applied to detect OTA concentration in corn samples with satisfied result. - Abstract: A simple, low-cost, and sensitive liposome-based colorimetric aptasensor has been developed to detect ochratoxin A (OTA). Specifically, a dumbbell-shaped probe was designed, including magnetic beads (MBs), double-stranded DNA (dsDNA), and enzyme-encapsulated liposome. The dsDNA formed by the hybridization between OTA aptamer and its complementary probe. And the dsDNA was used to contact the MBs and the enzyme-encapsulated liposome. In the presence of OTA, the aptamer preferred to combine with OTA to form G-quadruplex, resulting in the release of the detection probe and the enzyme-encapsulated liposome. Each liposome contained a large amount of HRP. Thus, when the liposome was lysed by adding the mixed solution of 3,3′,5,5′-tetramethylbenzidine (TMB) and H2O2, a large number of HRP were released. HRP could catalyze the H2O2-mediated oxidation of TMB and hence resulted in the color change from colorless to blue with the OTA concentration varying, and this variation can be observed by naked eyes easily. The result showed that the absorption intensity at 652 nm enhanced with the increase of OTA concentration ranging from 0.05 to 2.0 ng mL−1, and the limit of detection was calculated to be 0.023 ng mL−1 (S/N = 3). The developed colorimetric aptasensor has been applied to detect OTA concentration in corn samples with satisfied results.
[en] Overtime seaweeds have been used as a food mainly due to their high nutritional value. This type of food is considered as functional food and contributes to the nutritional human requirements, being beneficial to human health. In this study 13 edible seaweed samples acquired in the marked of São Paulo city were analyzed and the concentrations of elements Cl. K. Mg. Mn and Na were determined by Instrumental Neutron Activation Analysis (INAA). The following edible seaweeds were analyzed: Nori (Porphyra umbilicates); Hijiki (Hijikia fusiforme); Kombu (Laminaria sp.) and Wakame (Undaria pinnatifida) species from China, USA, Japan and South Korea. The Undaria pinnatifida species presented the highest Na concentration and the lowest K level. The highest variation was obtained for Mn in the Porphyra umbilicates species. (author)
[en] In this study, we report on the development of an open undivided electrochemical reactor with a compact fixed bed of glassy carbon pellets as three-dimensional cathode for the application of electro-Fenton process. Bisphenol A (BPA) was chosen as model molecule in order to improve its efficiency to the treatment of persistent pollutants. The study of the BPA removal efficiency in function of the applied current intensity was investigated in order to determine the limiting current of O2 reduction (optimal conditions of H2O2 production at flow rate of 0.36 m3.h−1) which was 0.8 A (0.5 A/100 g of glassy carbon pellets). Many parameters have been carried out using this electro-Fenton reactor namely degradation kinetics, influence of anodic reactions on DSA, effect of initial pollutant concentration. In the optimal current condition, the global production rate of H2O2 and ·OH was investigated. The yield of electro-Fenton reaction (conversion of H2O2 to ·OH) was very high (> 90%). The absolute rate of BPA degradation was determined as 4.3 × 109 M−1 s−1. COD, TOC and BOD5 measurements indicated that only few minutes of treatment by electro-Fenton process were needed to eliminate BPA for dilute solutions (10 and 25 mg.L−1). In this case, the biodegradability of the treated solutions occurred rapidly. For higher concentration levels, an efficient removal of BPA appeared for treatment time higher than 1 hour and more than 90 minutes were necessary to obtain the biodegradability of BPA solutions. In optimum conditions, the scale-up of the electrochemical reactor applied to electro-Fenton process was suggested and depended on the concentration level of the pollutant. The operating parameters of the scaled-up reactor might be deduced from the new section of each fixed bed exposed to the flow, from values of liquid flow velocity and from the corresponding limiting current density obtained with the reactor at laboratory scale. The compact fixed bed cathode in an open undivided electrochemical reactor appears as an appropriate solution as pre-treatment electro-Fenton process followed by the biological treatment of persistent pollutant.
[en] When water containing ionic substances is electrolyzed, electrolyzed water with strong bactericidal ability due to the available chlorine(AC) is generated on the anode side. Slightly acidic to neutral electrolyzed water (pH 6.5 to 7.5) is physiological pH and is suitable for biological applications. For producing slightly acidic to neutral electrolyzed water simply, a vertical-type electrolytic tank with an asymmetric structure was made. As a result, a small amount of strongly alkaline water was generated in the upper cathodic small chamber, and a large amount of weakly acidic water generated in the lower anodic large chamber. The pH and AC concentration in solutin mixed with both electrolyzed water were 6.3 and 39.5 ppm, respectively, This solution was slightly acidic to neutral electrolyzed water and had strong bactericidal activity. This device is useful for producing slightly acidic to neutral electrolyzed water as a disinfectant to employ at home care, when considering economic and environmental factors, since it returns to ordinary water after use.