Authors:Xiaoliang Wang, Guowen Peng, Yan Yang, Yanfei Wang, and Tingting He
Immobilized Saccharomyces cerevisiae (ISC) was prepared by the sodium alginate–gelatin embedding method after dry cells had been cross-linked by formaldehyde.
Adsorption of uranium(VI) by incompletely and completely dry ISC was studied. The results indicated that incompletely dry
ISC had greater adsorption capacity for U(VI), with physical adsorption being the primary mechanism, whereas completely dry
ISC exhibited much greater rigidity and much smaller volume. Therefore, initial absorption of U(VI) by incompletely dry ISC
followed by heating could be compared with glass solidification for disposal of radioactive waste. The influence of solution
pH, temperature, and contact time on U(VI) absorption was also studied, with pH being found to be the main influencing factor.
The adsorption mechanism of completely dry ISC was explored by scanning electron microscopy (SEM) and Fourier-transform infrared
(FTIR) spectroscopy, indicating that the main adsorption mechanism is chemical adsorption.
This work reports the synthesis, radiolabeling and preliminary biodistribution results in tumor-bearing mice of the 99mTc(CO)3–AOPA colchicine conjugate. The novel ligand was successfully synthesized by conjugation of N-(acetyloxy)-2-picolylamino (AOPA) to deacetylcolchicine via a short carbonyl-methylene linker. Radiolabeling was performed
in high yield with [99mTc(CO)3]+ core. 99mTc(CO)3–AOPA colchicine conjugate was hydrophilic and was stable at room temperature. Biodistribution studies in tumor-bearing mice
showed that 99mTc(CO)3–AOPA colchicine conjugate accumulated in the tumor with good uptake and retention. However, its clearance from normal organs
was not so fast, resulting in poor T/NT ratios. Further modification on the linker or/and 99mTc-chelate to improve the tumor targeting efficacy and in vivo kinetic profiles is currently in progress.
Authors:Zhiqiang Wang, Zhanwei Bu, Tiegang Ren, Tingting Cao, and Lirong Yang
The mechanism of the cycloaddition of CO2 with propylene oxide to afford propylene carbonate catalyzed by a highly active trans-dichlorotetrapyridineruthenium [trans-Ru(py)4Cl2] complex and tetrabutylammonium chloride (TBAC) has been studied by means of electrospray ionization mass spectrometry (ESI–MS), structural characterization of trans-Ru(py)4Cl2, catalyst activity tests and so on. Further experiments demonstrated that the tributylamine formed in situ was involved in the catalysis and that addition of butyl chloride to re-convert the tributylamine into TBAC resulted in the inhibition of the reaction. The mechanistic study explains the reported early experimental observations well and provides a clear profile for the cycloaddition of carbon dioxide with propylene oxide using trans-Ru(py)4Cl2 as catalyst. The mechanism also fully explains the role of the TBAC by providing a role for the in situ generated tributylamine in activating the carbon dioxide.
Authors:Xiangling Wang, Tingting Wang, Ricardo Muñoz Martín, and Yanfang Jia
This is a report on an empirical study on the usability for translation trainees of neural machine translation systems when post-editing (mtpe). Sixty Chinese translation trainees completed a questionnaire on their perceptions of mtpe's usability. Fifty of them later performed both a post-editing task and a regular translation task, designed to examine mtpe's usability by comparing their performance in terms of text processing speed, effort, and translation quality. Contrasting data collected by the questionnaire, keylogging, eyetracking and retrospective reports we found that, compared with regular, unaided translation, mtpe's usefulness in performance was remarkable: (1) it increased translation trainees' text processing speed and also improved their translation quality; (2) mtpe's ease of use in performance was partly proved in that it significantly reduced informants' effort as measured by (a) fixation duration and fixation counts; (b) total task time; and (c) the number of insertion keystrokes and total keystrokes. However, (3) translation trainees generally perceived mtpe to be useful to increase productivity, but they were skeptical about its use to improve quality. They were neutral towards the ease of use of mtpe.
Authors:Xiaobei Zheng, Feng Dong, Jing Yang, Xiaojiang Duan, Tingting Niu, Wangsuo Wu, and Jianjun Wang
This work reports the synthesis and preliminary biodistribution results of [131I]SIB-PEG4-CHC in tumor-bearing mice. The tributylstannyl precursor ATE-PEG4-CHC was synthesized by conjugation of ATE to amino pegylated colchicine NH2-PEG4-CHC. [131I]SIB-PEG4-CHC was radiosynthesized by electrophilic destannylation of the precursor with a yield of ~44%. The radiochemical purity
(RCP) appeared to be >95% by a Sep-Pak cartridge purification. [131I]SIB-PEG4-CHC was lipophilic and was stable at room temperature. Biodistribution studies in tumor-bearing mice showed that [131I]SIB-PEG4-CHC cleared from background rapidly, and didn’t deiodinate in vivo. However, the poor tumor localization excluded it from
further investigations as a tumor-targeted radiopharmaceuticals.
Authors:Tingting Fang, Xi Li, Chenggang Wang, Zhijun Zhang, Tian Zhang, Junmin Zeng, Peng Liu, and Chaocan Zhang
Cu(nor)2·H2O (1), Zn(nor)2·4H2O (2), Ni(nor)2·2H2O (3), [Cu(nor)(phen)]NO3·4H2O (4), [Zn(nor)(phen)]NO3·2H2O (5), and [Ni(nor)(phen)]NO3·3H2O (6) were synthesized and their action on Tetrahymena growth was studied by microcalorimetry. The growth constant (k), inhibitory ratio (I), and half-inhibiting concentration (IC50) were calculated, which showed that the complexes had a strong inhibitory effect on Tetrahymena. All these complexes can inhibit the growth of Tetrahymena more strongly than norfloxacin. The norfloxacin–metal complexes exhibited better inhibitory activity than nor–phen–metal complexes. The power–time curves of Tetrahymena growth in the presence of norfloxacin were also measured. It was found that all complexes showed higher inhibitory activity than norfloxacin. And the inhibitory mechanism was discussed preliminarily. The diverse inhibition may be due to the ability of the complexes to penetrate into cells and the effect of these complexes on the nucleic acid. Microcalorimetry has been used extensively in many biological and chemical investigations as a universal, non-destructive, continuously running, and highly sensitive tool.
Authors:Gang Xu, Tingting Bu, Minghong Wu, Jisan Zheng, Ning Liu, and Liang Wang
The degradation characteristics of clopyralid irradiated by electron beam (EB) was studied in aqueous solutions. The effects
of factors, such as initial clopyralid concentrations, addition of radicals scavenger, initial solution pH and addition of
H2O2, were investigated on clopyralid degradation efficiency and mechanism. It was found that the EB-radiolysis was an effective
way to degrade clopyralid and its degradation rate decreased with the increasing of substrate concentration. In the investigated
initial concentrations range of 100–400 mg L−1, the radiolytic degradation of clopyralid followed a pseudo-first kinetic order. The results from addition of radicals scavenger
indicated that both •OH and eaq− played significant roles in the degradation of clopyralid. Furthermore, the alkaline condition and addition of H2O2 (<10 mM) in the solution also slightly enhanced the efficiency of clopyralid degradation. The ion chromatography analysis
showed that some organic acids (formic acid, acetic acid and oxalic acid) were formed, while the completely dechlorination
of the substrate was achieved and organic nitrogen was recovered in the form of ammonium and nitrate ions during the irradiation
Authors:Junbo Zhang, Qian Yu, Jinfeng Huo, Yan Pang, Sheng Yang, Yining He, Tingting Tang, Chenchen Yang, and Xuebin Wang
The dimercaptosuccinic acid metronidazole ester (DMSAMe) was synthesized and radiolabeled with 99mTc to form the 99mTc-DMSAMe complex in high yield. The radiochemical purity of the 99mTc-DMSAMe complex was over 90%, as measured by TLC and by HPLC, without any notable decomposition at room temperature over
a period of 6 h. Its partition coefficient indicated that it was a lipophilic complex. The tumor cell experiment and the biodistribution
in mice bearing S 180 tumor showed that the 99mTc-DMSAMe complex had a certain hypoxic selectivity and accumulated in the tumor with high uptake and good retention. The
tumor/blood and tumor/muscle ratios increased with time, suggesting it would be a possible tumor hypoxia imaging agent.