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  • Author or Editor: Yi Zhao x
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Abstract  

A keyword analysis was applied in this work to evaluate research trends of DDT (1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane) papers published between 1991 and 2005 in any journal of all the subject categories of the Science Citation Index compiled by ISI (Institute for Scientific Information, Philadelphia, USA). DDT was used as a keyword to search parts of titles, abstracts, or keywords. The published output analysis showed that DDT research steadily increased over the past 15 years and the annual publication output in 2005 was about twice that of 1991. The two peaks in 1997 and 2000 were closely related to two new research fields on DDT, namely the endocrine disruption and the persistent organic pollutants (POPs). A paper entitled “Persistent DDT metabolite p,p’-DDE is a potent androgen receptor antagonist” published in 1995 in Nature by Kelce et al. firstly discovered DDT’s toxicity for humans. As a result, public concerns regarding DDT ballooned and now play a key role in DDT research. Keyword analysis indicated that the research interest changed remarkably from 1991 to 2005. “Endocrine disruption” was one of the most frequently used author keywords in the period between 2002 and 2005 whilst it did not appear before 1997. The new conception of POPs showed the same trend. The whole paper published by India and Mexico ranked at 6th and 13th. That showed that DDT research is often related with DDT’s risk and benifits to humans.

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Authors: Dong Wenming, Wang Xiangke, Shen Yi, Zhao Xudong and Tao Zuyi

Abstract  

The factors affecting the sorption of radiocobalt by bentonite and kaolinite were studied with the aim to assess important factors which should be included in modelling radiocobalt migration in soils and waters. The distribution coefficients of radiocobalt sorption on bentonite and kaolinite from aqueous solutions were determined by using the batch method, and it was found that they were insensitive to the loading, the initial pH, the ionic strength, the humic substance and the sorption direction. Thus, the sorption characteristics of radiocobalt on bentonite and kaolinite facilitated the mathematical modelling of radiocobalt migration. In addition, the sorption kinetics and the sorption mechanism of radiocobalt on bentonite and kaolinite were also examined.

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Authors: Shen Xuesong, Wang Tao, Jin Meihua, Zhao Chunxia, Qin Xuelian, Liu Hanfu, Qiu Zhuangping and Liu Yi

Abstract

A thermal dynamic model of nanoformulations entrapped in artesunate liposomes was established and biological thermodynamics was applied for investigation of the drug formulations. Effects of artesunate liposomes on the growth metabolism of Escherichia coli were studied by microcalorimetry. The results showed that (1) Comparison of artesunate and artesunate liposomes, the thermogenesis curves of E. coli were significant different in the metabolic process: lag phase (AB), log phase (BC), stationary phase (CD), and decline phase (DE); (2) Linear fit of the data of total metabolic heat of E. coli effected by different concentration artesunate (1–300 μg), the equation can be obtained as follows: Y = 364720.61−1075.25x, R = 0.9985; Linear fit of the data of total metabolic heat of E. coli effected by different concentration artesunate liposomes (30–120 μg), the linear equation can be obtained as follows: Y = 54251.5765−35.71122x, R = 0.98345; (3) The half inhibitory concentration I C50 was 50.05 μg/mL, the relative sensitivity was obviously different; (4) Artesunate liposomes having better sustained release properties as compare to artesunate.

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Authors: Chu Jinfeng, Wang Xuebin, Lv Gongxu, Zhao Yi, Zhang Junbo, Wang Jincheng, Mi Hongzhi and Yang Hao

Abstract  

The purpose of the investigation was to evaluate the feasibility of imaging inflammatory lesions with five small molecular weight complexes of 99mTc. The labeling yields of D-glucaric acid (D-Gca), citric acid (Cit), DL-malic acid (DL-Mal), L-malic acid (L-Mal) and tartaric acid (Tar) were all more than 90%. The percentage uptake/g tissue of them and 99mTc-pertechnetate (P) in mice with turpentine-induced abscesses and abscess/muscle (A/M), blood (A/B), liver (A/L), kidney (A/K) concentration ratios were calculated. The maximum A/M ratios were 4.02±0.21 (Cit, 3h), 4.30±0.77 (D-Gca, 3h), 4.04±0.21 (DL-Mal, 6h), 3.50±0.23 (L-Mal, 1h), 3.20±0.17 (Tar, 1h) and 3.23±0.41 (P, 1h) respectively. The scintigram was obtained in a rabbit with turpentine-induced abscess after 99mTc-D-Gca i.v. injection. Results demonstrated they all can accumulate in inflammatory lesions. Of them, 99mTc-D-Gca is probably a potential imaging agent on inflammatory lesions.

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Authors: Fahar Ibtisham, Yi Zhao, Jiang Wu, Aamir Nawab, Xiao Mei, GuangHui Li and Lilong An

Introduction

The ability for isolation and in vitro propagation of spermatogonial stem cells (SSCs) offer a base for studies on spermatogenesis, and also contribute to the development of new methods for the preservation of livestock and animal genetic modification. The aim of this study was to find the optimal isolation and culture condition for efficient propagation of SSCs.

Methods

Three different isolation methods (mechanical, one-, and two-step enzymatic digestion) were compared to find the optimal isolation method. To find the best culture conditions for in vitro propagation, isolated SSCs were cultured for 7 days in three different culture conditions supplemented with 10% FBS, 0.25% BSA, and 10% KSR, respectively.

Results

The result showed that two-step enzymatic digestion produced a significant high fraction of live cells compared the other two. Non-adhering cells collected after 48 hr and cultured in BSA- and KSR-supplemented medium had a significantly high number of SSCs clump formation compared to FBS-supplemented group. The expression of CD9 confirmed that cell clumps were SSCs clumps. Spermatogonial stem cells cultured in BSA-supplemented medium were positive for NGN3 and PLZF expressions, whereas negative for Stra8 (a meiotic-specific gene) expression, suggesting that most of the cells were undifferentiated SSCs in BSA culture system. In contrast, in FBS- and KSR-supplemented groups, the SSCs were positive for NGN3, PLZF, and Stra8.

Conclusion

These data revealed that two-step enzymatic digestion is the best method for the isolation, and 0.25% BSA-supplemented culture condition is effective for optimal in vitro propagation of SSCs.

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Atractylodis exerted a variety of pharmacological effects such as anti-tumor, anti-inflammatory, anti-bacterial, and anti-aging effects etc. The major ingredients of Atractylodis are atractylenolide I and II that exhibited activities in anti-inflammatory and anticancer. In this work, a sensitive and selective ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method for determination of atractylenolide I and II in rat plasma was developed. The UPLC–MS/MS method was validated for selectivity, linearity, accuracy, precision, recovery, and stability with a total run time of 4.0 min. After addition of atractylenolide III as an internal standard (IS), protein precipitation by acetonitrile was used to prepare samples. Chromatographic separation was achieved on a UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) with 0.1% formic acid and acetonitrile as the mobile phase with gradient elution. An electrospray ionization source was applied and operated in positive ion mode; multiple reactions monitoring (MRM) mode was used for quantification using target fragment ions m/z 231.1 → 185.1 for atractylenolide I, m/z 233.1 → 91.0 for II, and m/z 249.0 → 231.1 for IS. Calibration plots were linear throughout the range 1–1000 ng/mL for atractylenolide I and II in rat plasma. Mean recoveries of atractylenolide I and II in rat plasma ranged from 86.2% to 96.3%. Relative standard deviation (RSD) of intra-day and inter-day precision was both less than 12%. The accuracy of the method was between 91.0% and 109.0%. The method was successfully applied to pharmacokinetic study of atractylenolide I and II after intravenous administration in rats.

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Abstract  

The decomposition reaction kinetics of the double-base (DB) propellant (No. TG0701) composed of the mixed ester of triethyleneglycol dinitrate (TEGDN) and nitroglycerin (NG) and nitrocellulose (NC) with cerium(III) citrate (CIT-Ce) as a combustion catalyst was investigated by high-pressure differential scanning calorimetry (PDSC) under flowing nitrogen gas conditions. The results show that pressure (2 MPa) can decrease the peak temperature and increase the decomposition heat, and also can change the mechanism function of the exothermal decomposition reaction of the DB gun propellant under 0.1 MPa; CIT-Ce can decrease the apparent activation energy of the DB gun propellant by about 35 kJ mol−1 under low pressure, but it can not display the effect under high pressure; CIT-Ce can not change the decomposition reaction mechanism function under a pressure.

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Abstract  

A statistical analysis is made of two data sets and it is found that the distribution of major scientific and technological achievements in terms of the age of those achievement makers is Weibull distribution. Pearson'sx 2 test results are satisfactory. This finding holds for different centuries, different nations and different disciplines.

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Authors: Xing Xiaoling, Xue Liang, Zhao Fengqi, Yi Jianhua, Gao Hongxu, Xu Siyu, Pei Qing, Hao Haixia and Hu Rongzu

Abstract

The enthalpies of dissolution in ethyl acetate and acetone of hexanitrohexaazaisowurtzitane (CL-20) were measured by means of a RD496-2000 Calvet microcalorimeter at 298.15 K, respectively. Empirical formulae for the calculation of the enthalpy of dissolution (Δdiss H), relative partial molar enthalpy (Δdiss H partial), relative apparent molar enthalpy (Δdiss H apparent), and the enthalpy of dilution (Δdil H 1,2) of each process were obtained from the experimental data of the enthalpy of dissolution of CL-20. The corresponding kinetic equations describing the two dissolution processes were for dissolution process of CL-20 in ethyl acetate, and for dissolution process of CL-20 in acetone.

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Abstract  

The thermal decomposition mechanism of hydrazine 3-nitro-1,2,4-triazol-5-one (HNTO) compound was studied by means of differential scanning calorimetry (DSC), thermogravimetry and derivative thermogravimetry (TG-DTG), and the coupled simultaneous techniques of in situ thermolysis cell with rapid scan Fourier transform infrared spectroscopy (in situ thermolysis/RSFTIR). The thermal decomposition mechanism is proposed. The quantum chemical calculation on HNTO was carried out at B3LYP level with 6-31G+(d) basis set. The results show that HNTO has two exothermic decomposition reaction stages: nitryl group break first away from HNTO molecule, then hydrazine group break almost simultaneously away with carbonyl group, accompanying azole ring breaking in the first stage, and the reciprocity of fragments generated from the decomposition reaction is appeared in the second one. The C–N bond strength sequence in the pentabasic ring (shown in Scheme 1) can be obtained from the quantum chemical calculation as: C3–N4 > N2–C3 > N4–C5 > N1–C5. The weakest bond in NTO is N7–C3. N11–N4 bond strength is almost equal to N4–C5. The theoretic calculation is in agreement with that of the thermal decomposition experiment.

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