Authors:M. Dong, J. Huang, H. Du, J. Li, S. Du, A. Luo, Y. Jiang, and C. Zhang
By substututing99Mo for the Mo in the reconstituted MoFe protein, the nuclear quadrupole interactions (NQI) of99Mo have been measured using the perturbed angular correlations (PAC). Two well-defined electric quadrupole interaction parameters have been observed. The configuration of the M-Center of the MoFe protein is identified by the quadrupole couplign constant
Q1(412(9)MHz) and the asymmetry parameter
1(0.49(5)). Other parameters, VQ2(1939(13)MHz) and
1(0.90(1)), may correspond to a deformation M—Center of MoFe protein.
Authors:S. Du, G. Zhang, H. Li, P. Wang, and X. Wang
The free-radical bulk polymerization of 2,2-dinitro-1-butyl-acrylate (DNBA) in the presence of 2,2′-azobisisobutyronitrile
(AIBN) as the initiator was investigated by DSC in the non-isothermal mode. Kissinger and Ozawa methods were applied to determine
the activation energy (Ea) and the reaction order of free-radical polymerization. The results showed that the temperature of exothermic polymerization
peaks increased with increasing the heating rate. The reaction order of non-isothermal polymerization of DNBA in the presence
of AIBN is approximately 1. The average activation energy (92.91±1.88 kJ mol −1) obtained was smaller slightly than the value of Ea=96.82 kJ mol−1 found with the Barrett method.
2,2-dinitropropyl acrylate (DNPA), 2,2-dinitrobutyl acrylate (DNBA) and 2,2-dinitrobutyl methacrylate (DNBMA) were synthesized
and the kinetics of their free-radical polymerization in the presence of 2,2′-azobisisobutyronitrile (AIBN) were investigated
by DSC in the non-isothermal mode. The kinetics of the free-radical polymerization as estimated by the Kissinger and Ozawa
methods showed that the reaction is disfavoured by increasing steric hindrance around the acrylyl double bond. The rate constants
calculated from the activation parameters showed the structural dependency. The polymerization kinetics revealed that the
polymerizability of three monomers decreased due to the presence of substituent methyl groups on the acrylyl double bond and
2,2-dinitrobutyl on ester group. Thus, the polymerization tendency increased in the order DNPA>DNBA>DNBMA.
Authors:F. F. (Russ) Knapp Jr., S. Mirzadeh, A. L. Beets, and M. Du
Greater availability of therapeutic radioisotopes is required to meet the demands for increasing clinical applications in nuclear medicine, oncology and interventional cardiology. Because of the need for very high specific activity products, methods other than direct neutron capture reactions (n,γ-elastic and n,n’-inelastic routes) are required to insure that the highest specific activity - and hopefully no carrier added (nca) - radioisotopes are available. Two major methods to obtain nca radioisotopes from reactors are through the use of radionuclide generator systems using reactor-produced parents and the formation of desired radioisotopes through beta-decay of reactor-produced species. In this paper we describe our recent development of new approaches to obtain nca 177Lu from the decay of reactor-produced 177Yb and free of the long-lived 177mLu (T1/2 = 160 d) radiocontaminant. We also describe preliminary results of our new “indirect” method for the production of 195mPt via decay of 195mIr, reactor-produced by neutron irradiation of highly enriched 193Ir.
Authors:T.-K. Wang, Y.-D. Yang, B. Du, S. Yu, and W.-L. Hou
Chestnut exhibits anti-inflammatory, styptic, anti-diarrhea, and analgestic effects as a traditional Chinese medicine. There is increasing evidence that shows that the consumption of chestnuts has become more important in human nutrition due to the health benefits provided by the antioxidants. The phenolic compounds are responsible for major bioactivities, such as anti-tumor and anti-oxidation. A high-performance liquid chromatography (HPLC) method with diode array detection (DAD) was established for the simultaneous determination of six phenolic compounds (gallic acid, GA; protocatechuic acid, PR; catechin, CA; epicatechin, EP; quercetin, QU; kaempferol, KA) in Chinese chestnut (Castanea mollissima blume) kernel. The sample followed by separation on Eclipse XDB-C18 column (150 × 4.6 mm, id., 5 μm) with gradient elution of methanol-1.0% acetate acid solution as a mobile phase, at a temperature of 30°C, under the ratio of 1.2 mL min−1, with 5 μL injection volume, and multi-wavelength synthesis was used with DAD. The correlation coefficients were larger than 0.999, the recoveries were 97.58% for GA, 100.41% for PA, 96.23% for CA, 101.38% for QU, 99.15% for EP, and 98.60% for KA, relative standard deviation (RSD) were 1.04% for GA, 1.21% for PA, 1.09% for CA, 1.19% for QU, 1.06% for EP, and 1.20% for KA. This method was applied for the determination of phenolics in chestnut kernel and was found to be fast, sensitive, and suitable.
Authors:J. Du, H. Song, D. Mu, D. Li, S. Yan, and Y. Gu
The sorption/desorption of radioruthenium was investigated by the batch method in sea water system at ambient temperature
on the surface sediments obtained around the Daya Bay of Guangdong Province, where the first nuclear power station of China
has been running from 1994. It was found that the sorption percentage was obtained to be around 40% for all the surface sediments
in 60 minutes. Then, the sorption percentage goes up slowly. The sorption percentage of radioruthenium reached around 80%
in 113 days (2713 hours). The distribution coefficients decreased from 3.16·104 to 1.35·103 ml/g with the increasing of sediment concentration in the range of 4–10000 mg/l. The results of the desorption experiments
suggest that the sorption of radioruthenium is irreversible with 81.5% relative hysteresis coefficient.
Authors:D. Mu, H. Song, S. Yan, Y. Gu, D. Li, and J. Du
Three kinds of marine bivalves (wild Saccostrea cucullata, aquacultured Perna viridis and aquacultured Pinctada martens), collected from Daya Bay, the South China Sea, were used to investigate the bio-accumulation of radioruthenium in the glass
aquarium with natural seawater (pH 8.20, 35‰ salinity, filtered by 0.45 μm) at ambient temperature under laboratory feeding
conditions. The experimental results show that the stead-state of biology concentration factor (BCF, ml/g) of radioruthenium
was approached around 6 days for most species of bivalves. The values of BCF in shells are the highest in organs all the three
bivalves. The orders of BCF values (ml·g−1) are as: Perna viridis (33.2) < Saccostrea cucullata (47.0) < Pinctada martensi (208.4) for shells and Saccostrea cucullata (1.5) < Pinctada martensi (2.2) ≈ Perma viridis (2.4) for soft tissues, respectively, after exposed for 14 days. The rate constants of uptake and elimination of radioruthenium
on marine bivalves were also discussed by first-order kinetics model. The Pinctada martensi may be applicable to be an indicator for monitoring radioruthenium among the three bivalves.
Authors:L. Fu, Y. Chen, H. Du, J. Mao, X. Shi, and S. Li
A novel double -diketone 1,6-bis(1-phenyl-3-methyl-5-oxo-pyrazol-4-yl) hexanedione-[1,6] (BPMOPH) was further studied on its coordination compounds with uranium and thorium, respectively. The IR, UV, and1H-NMR spectra were examined, and the proposed structure is discussed.
Authors:D. H. Mu, J. Z. Du, D. J. Li, H. Q. Song, S. P. Yan, and Y. J. Gu
The comprehension of the behavior of radioactive nuclides in aquifer requires the study of the sorption processes of nuclides
in various geochemical conditions. The sorption/desorption of 65Zn(II) on surface sediments (0-2 cm) was investigated by batch method in sea water (pH 8.20, 35‰ salinity, filtered by 0.45mm)
at ambient temperature. The surface sediments were obtained from four stations around the Daya Bay of Guangdong Province (China),
where the first nuclear power station of China has been running from 1994. The sorption process is fast initially and around
39% average of sorption percentage (SP%) can be quickly obtained in 15 minutes for all the surface sediments. Then, the sorption
percentage becomes constant. In 30 days of contact time 79.6% sorption percentage and Kd=3.9. 103ml/g distribution coefficient was obtained. The value of Kdbecame constant, 4.0. 103ml/g, in contact time more than 120 hours. The distribution coefficient Kddecreases with increasing sediment concentration from 4.0 to 250 mg/l from 1.31. 104to 1.68. 103ml/g, respectively. Then the value of Kdgoes up to 5.38. 103ml/g with sediment concentration of 3000 mg/l. The desorption experiments suggest that the sorption of Zn(II) is irreversible
with a hyteresis coefficient of 66%.