Authors:P. Zhao, Q. Hu, T. Rose, G. Nimz, and M. Zavarin
99Tc and 129I are important contributors to risk assessment due to their long half-lives and high mobility as aqueous anionic species.
We analyzed 99Tc and 129I in groundwater samples in and near 11 underground nuclear tests and in melt glass and rock samples retrieved from the Chancellor
test cavity, Nevada Test Site. The 129I/127I ratio ranges from 10−3 to 10−6 in cavity water and 10−4 to 10−9 in satellite wells. The 99Tc concentration ranges from 3 to 10−4 Bq/l in cavity waters and from 0.3 to 10−4 Bq/l in satellite wells. Downstream migration is apparent for both radionuclides. However, it is affected by both retardation
and initial distribution. In-situ 99Tc and 129I Kds calculated using rubble and water concentrations are 3 to 22 ml/g and 0 to 0.12 ml/g, respectively, and are suggestive of
mildly reducing conditions. 129I distribution in the melt glass, rubble and groundwater of the Chancellor test cavity is 28%, 24% and 48%, respectively,
for 99Tc, it is 65%, 35% and 0.3%, respectively. Our partitioning estimates differ from those of underground tests in French Polynesia,
implying that fission product distribution may vary from test to test. Factors that may influence this distribution include
geologic conditions (e.g., lithology, water and CO2 content) and the cooling history of the test cavity.
Authors:Y. Zhao, C. Zhang, C. Qi, S. Feng, G. You, Z. Fu, F. Guo, and R. Wang
Two peptide ligands conjugated adenine, [9-N-(tritylmercapto acetyl diglycyl aminoethyl) adenine, Tr-MAG2-Ade] and [9-N-(tritylmercapto acetyl triglycyl aminoethyl) adenine, Tr-MAG3-Ade], are synthesized and labeled with 99mTc by directly labeling method. The stability of 99mTc-MAG2-adenine and 99mTc-MAG3-adenine in vitro is measured. The uptake radios of tumor to muscle at 3h post-injection are 5.70 and 4.92, respectively.
The biodistribution and scintigraphic imaging studies show that the two complexes have high localization in tumor and high
contrasted tumor images can be obtained, which suggest their potential utility as tumor imaging agents. But the high radioactivity
of abdomen could prevent the tumor imaging in this area.
Authors:L.-M. Zhang, W.-G. Xie, T.-T. Wen, and X. Zhao
The thermal behavior of five free anthraquinones (chrysophanol, emodin, physcion, aloe-emodin, and rhein) from rhubarb had
been investigated using TG, DTG and DTA technique. The results show that all the free anthraquinones have the similar TG and
DTG curve shapes, however, due to the substituted groups attached on the skeleton of 1,8-dihydroxy anthraquinone are different,
every anthraquinone has different mass loss features. Moreover, all the DTA curves of these free anthraquinones have two obviously
characteristic peaks, but with special curvilinear types, peak location and peak values. Therefore, thermal analysis (TA)
characteristics of anthraquinones above mentioned could be established, and it is possible to easily distinguish these anthraquinones
by using TA technique.
Authors:L. Lv, L. Zhao, X. Wang, H. Zhang, Z. Zhu, Y. Chai, and G. Zhang
Epimedium pubescens Maxim. and Epimedium koreanum Nakai. are two common and confused species of Herba Epimedii in Chinese Pharmacopoeia 2010 edition. Different species and growing conditions lead to chemical differences between the two species which may result in the improper clinical usage. In this work, a new method based on rapid-resolution liquid chromatography combined with time-of-flight mass spectrometry (RRLC/TOFMS) has been developed for identification and differentiation of major flavonoids in two kinds of Epimedium extract and rat plasma. The compounds were identified effectively based on the accurate extract masses and formulae acquired by RRLC/TOFMS. The fragmentation rules deduced by collision-induced dissociation (CID) were successfully implemented in distinguishing some of the isomers, further validating the results. By using the combined analytical techniques, a total of 40 major flavonoids in extracts of two kinds of Epimedium were identified within 30 min, including 31 common components and 9 characteristic components. After oral administration, three prototype compounds in rat plasma were detected by comparing the constituents measured in vitro with those in vivo, and five metabolites were identified by contrasting the fragmentation rules. The identification and structural elucidation of the chemical constituents provided essential data for further pharmacological and clinical studies on different species of Epimedium.
Authors:Z. Zhang, T. Cui, J. Zhang, H. Xiong, G. Li, L. Sun, F. Xu, Z. Cao, F. Li, and J. Zhao
The molar heat capacities of the room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluoroborate (BMIPF6) were measured by an adiabatic calorimeter in temperature range from 80 to 390 K. The dependence of the molar heat capacity
on temperature is given as a function of the reduced temperature (X) by polynomial equations, CP,m (J K−1 mol−1) = 204.75 + 81.421X − 23.828 X2 + 12.044X3 + 2.5442X4 [X = (T − 132.5)/52.5] for the solid phase (80–185 K), CP,m (J K−1 mol−1) = 368.99 + 2.4199X + 1.0027X2 + 0.43395X3 [X = (T − 230)/35] for the glass state (195 − 265 K), and CP,m (J K−1 mol−1) = 415.01 + 21.992X − 0.24656X2 + 0.57770X3 [X = (T − 337.5)/52.5] for the liquid phase (285–390 K), respectively. According to the polynomial equations and thermodynamic relationship,
the values of thermodynamic function of the BMIPF6 relative to 298.15 K were calculated in temperature range from 80 to 390 K with an interval of 5 K. The glass transition
of BMIPF6 was measured to be 190.41 K, the enthalpy and entropy of the glass transition were determined to be ΔHg = 2.853 kJ mol−1 and ΔSg = 14.98 J K−1 mol−1, respectively. The results showed that the milting point of the BMIPF6 is 281.83 K, the enthalpy and entropy of phase transition were calculated to be ΔHm = 20.67 kJ mol−1 and ΔSm = 73.34 J K−1 mol−1.