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  • Author or Editor: C. Li x
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Summary

Two rapid, sensitive and reproducible methods for the determination of baclofen(BAL) in urine and plasma based on high-performance liquid chromatography (HPLC) with UV-vis and fluorescent detection, respectively, were developed for the first time using a new synthesized fluorescent label, 6-oxy-(N-succinimidylacetate)-9-(2′-methoxycarbonyl) fluorescein (SAMF). The optimal derivatization yield was achieved in borate buffer (pH 8.0) for 15 min at room temperature (25 °C). With a mixture of methanol and water containing 5 mmol L−1 sodium citrate buffer (pH 5.0) as mobile phase, BAL was determined at λ = 455 nm with UV-vis detection and at λ ex/λ em = 488/520 nm with FD detection. The detection limits are 1.065 × 10−3 mg mL−1 and 1.065 × 10−2 mg mL−1 with HPLC-UV-vis and HPLC-FD, respectively. The proposed method has been successfully applied to the analysis of BAL in human urine and plasma samples. The established method is rapid (15 min of derivatization process and 10 min of chromatographic run), reproducible and sensitive.

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Abstract  

The interactions of lanthanide ions (Ln3+) with bovine serum albumin (BSA) under mimetic physiological conditions (310.15 K, pH 6.7, 0.1MNaCl) were studied by microcalorimetry. For the first time, based on Two Sets of Independent Sites Model, molar enthalpies (Δr H m1, Δr H m2) and coordination number (n 1, n 2) of the two sets of binding sites with different affinity were obtained directly from the microcalorimetric results. It was shown that the interactions are endothermic and entropy-driving processes. By combining with fluorescence spectroscopy, other thermodynamic parameters (Δr G m1, Δr S m1) were determined for high-affinity specific sites.

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Abstract  

In order to enrich the thermokinetic research methods and enlarge the applicable range of the thermokinetic time-parameter method, the integral and differential thermokinetic equations of consecutive first-order reaction have been deduced, and the mathematical models of the time-parameter method for consecutive first-order reactions have been proposed in this paper. The rate constants of two steps can be calculated from the same thermoanalytical curve measured in a batch conduction calorimeter simultaneously with this method. The thermokinetics of saponifications of diester in aqueoushanol solvent has been studied. The experimental results indicate that the time-parameter method for the consecutive first-order reaction is correct.

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Authors: C. Liu, S. Li, X. Wang, Z. Wang, H. Wang, R. Li, C. Xin, B. Li, L. Jiang and C. Jia

Abstract  

The migration of 99Tc in unsaturated Chinese loess was investigated in-situ with a tracer method. Quartz containing 3H (HTO) and 99Tc (99TcO4 -) was introduced into the bottom of an experimental pit which was then backfilled at the field test site. Then core soil samples were taken and cut vertically into 1 cm long slices. The slice samples were analyzed by liquid scintillation techniques in the laboratory. The results indicate that the migration pattern of 99Tc was quite similar to that of 3H and the vertical diffusion coefficients of 99Tc and 3H were calculated as (4.7±0.4).10-2 cm2/d and (7.8±0.4).10-2 cm2/d, respectively.

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Authors: C. Liu, Z. Wang, S. Li, Y. Yang, B. Li, H. Jiang, L. Jiang, L. Wang and D. Li
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Authors: H. Quan, Z. Ge, Z. Li, C. Yin, K. Zhong, Z. Hao, H. Li and F. Ji

Abstract  

The desorption behaviour (desorption temperature and extent of desorption) of HF,HCFC-133a (CF3CH2Cl) and HFC-134a (CF3CH2F) on γ-AlF3 or catalyst supported on γ-AlF3 was studied using an adsorption apparatus and TG, DTA and DSC methods. On the basis of the results a reaction mechanism was proposed for the preparation of HFC-134a. The γ-AlF3 employed for preparing the catalyst was expected to be stable below 550C based on the crystalline phase transition temperature of γ-AlF3.

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The purpose of this study was to evaluate the ability of Lactobacillus rhamnosus to bind patulin (PAT) in the buffer solution and apple juice. The binding of L. rhamnosus to PAT was reversible, which improved the stability of the bacterial complex. The ability to bind PAT can be enhanced with the inactivation of the strain by high temperature and acid treatment. Acid-treated bacteria had the highest PAT binding rate of 72.73±1.05%. The binding rates of acid and high temperature (121 °C) treatments were increased by 21.37% and 19.15%, respectively. L. rhamnosus showed the best detoxification ability to PAT at 37 °C, where the binding rate reached 50.9±1.03%. When the dose of inactivated bacteria powder was 0.02 g ml−1, the minimum concentration of PAT in apple juice was 0.37 µg ml−1. The addition of the L. rhamnosus inactivated powder did not affect the quality of the juice product and effectively bound the PAT in apple juice.

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Authors: M. Bertolotti, G. L. Liakhou, R. Li Voti and C. Sibilia

The photodeflection technique is useful not only for thermal diffusivity measurements but also to supply a thermal imaging system. The experimental setup and the basic theoretical aspects for determining the temperature profile are discussed together with the experimental results on a semiconductor laser diode.

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Abstract  

Liquid crystalline polymer/polyamide 66 (LCP/PA66) and LCP/poly(butyl terephthalate) (LCP/PBT) blends were compounded using a Brabender Plasticorder equipped with a mixing chamber. The LCP employed was a semi-flexible liquid crystalline copolyesteramide based on 30 mol% of p-amino benzoic acid (ABA) and 70 mol% of poly(ethylene terephthalate) (PET). The Flory-Huggins interaction parameters (χ12) of the LCP/ PA66 and LCP/PBT blends are estimated by melting point depression from DSC measurement. The results indicate that c12 values all are negative for LCP/PA66 and LCP/PBT blends, and when the LCP content in these blends is more than 10 mass%, the absolute value of χ12 decreases. Thereby, we can conclude that LCP/PA66 and LCP/PBT blends are fully miscible in the molten state, the molecular interaction between the LCP and PA66 is stronger than that between LCP and PBT. As the LCP content in LCP/PA66 and LCP/PBT blends is more than 10 mass%, the molecular interaction between LCP and matrix polymer decreases.

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