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Journal of Thermal Analysis and Calorimetry
Authors:
Li Bai Xiao
,
Xiao Ling Xing
,
Xue Zhong Fan
,
Feng Qi Zhao
,
Zhi Ming Zhou
,
Hai Feng Huang
,
Ting An
,
Hai Xia Hao
, and
Qing Pei

Abstract

The enthalpies of dissolution for di(N,N-di(2,4,6,-trinitrophenyl)amino)-ethylenediamine (DTAED) in dimethyl sulfoxide (DMSO) and N-methyl pyrrolidone (NMP) were measured using a RD496-2000 Calvet microcalorimeter at 298.15 K. Empirical formulae for the calculation of the enthalpies of dissolution (Δdiss H) were obtained from the experimental data of the dissolution processes of DTAED in DMSO and NMP. The linear relationships between the rate (k) and the amount of substance (a) were found. The corresponding kinetic equations describing the two dissolution processes were for the dissolution of DTAED in DMSO, and for the dissolution of DTAED in NMP, respectively.

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Abstract  

99Tc is an important radionuclides related to repository safety assessment. The mobility pertechnetate (TcO4 ) can be reduced to immobility technetium(IV) hydrous oxides (TcO2·nH2O) by Fe(II)-bearing minerals. In China, Gaomiaozi (GMZ) bentonite is regarded as the favorable candidate backfilling material for the HLW repository, which is contained some FeO. The diffusion behavior of 99Tc was investigated in GMZ bentonite by through- and out-diffusion methods. The effective diffusion coefficient (D e), the accessible porosity (εacc), apparent diffusion coefficient (D a) and distribution coefficient (K d) were decreased with the increasing of dry density. The D e values were (2.8 ± 0.2) × 10−11 m2/s and (3.5 ± 0.2) × 10−12 m2/s at dry density of 1,600 and 1,800 kg/m3, respectively. It was indicated that the dominating species was TcO4 during the diffusion processing. While, out-diffusion results showed that part of TcO4 may be reduced by Fe(II). The relationship of D e and εacc could be described by Archie’s law with exponent n = 2.4 for 99Tc diffusion in GMZ bentonite. Furthermore, the relationship between D a and dry density (ρ) was exponential.

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Abstract  

The copper(II) complex of 6-benzylaminopurine (6-BAP) has been prepared with dihydrated cupric chloride and 6-benzylaminopurine. Infrared spectrum and thermal stabilities of the solid complex have been discussed. The constant-volume combustion energy, Δc U, has been determined as −12566.92±6.44 kJ mol−1 by a precise rotating-bomb calorimeter at 298.15 K. From the results and other auxiliary quantities, the standard molar enthalpy of combustion, Δc H m θ, and the standard molar of formation of the complex, Δf H m θ, were calculated as −12558.24±6.44 and −842.50±6.47 kJ mol−1, respectively.

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Abstract

The power–time curves of mice splenic lymphocytes growth at 37 °C affected by ginsenoside Rh2 were determined by microcalorimetry using a 3114/3236 TAM air bioactivity monitor with ampoule mode. Then, the minimal inhibitory concentration (MIC) of Rh2 on splenic lymphocytes growth was determined by serial dilution method. From factor analysis (FA) on six quantitative thermokinetic parameters from the power–time curves, the activity of Rh2 on splenic lymphocytes could be quickly evaluated by analyzing the changes in the two main parameters: growth rate constant k, and maximum heat-output power, P m. The results showed that Rh2 had strong inhibitory activity on splenic lymphocytes growth, and this inhibitory activity was strengthened with increasing concentration of Rh2 in the concentration range of 1.0–32.0 μg mL−1. This strong inhibitory also could be confirmed from the MIC of 50.0 μg mL−1 of Rh2 on splenic lymphocytes growth in RPMI-1640 culture medium. This study illustrated that microcalorimetry could not only offer a useful method for evaluating the activity of drugs, but also serve as a quantitative, sensitive, and simple analytic tool for the evaluation of drugs on cell growth.

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Abstract  

In the present study a method using enriched stable isotope tracer and instrumental neutron activation analysis (INAA) was developed to study the dynamic distribution of rare earth elements (REEs) in a variety of organs and tissues of Wistar rats. Stable isotopes 152Sm and 168Yb were selected as tracers for the experiment. Intravenously injected 152Sm and 168Yb in chloride form could be quickly absorbed and distributed in almost all the organs and tissues of interest, including liver, skeleton, kidney, spleen, heart, lung, testicle, and blood serum. Liver and skeleton had high ability to take up 152Sm and 168Yb under the experimental conditions, whereas the contents of the elements in other organs were generally lower than 2% of the given dose during the whole experimental period. The difference in distribution of 152Sm and 168Yb in the body was also discussed.

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Abstract  

Chemical behavior of lanthanum in root tips excized from wheat seedlings growing at both promotional and inhibitory levels of LaCl3 in culture solutions was investigated by a sequential leaching procedure combined with instrumental neutron activation analysis. The results indicate that most of La exists in non-exchangeable species and the binding of La3+ to the root tips is extremely stable. The root tips during growing at the inhibitory level of LaCl3 absorb much more La than those at the promotional level. However, the La proportion in each fraction is similar for both groups.

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JPC - Journal of Planar Chromatography - Modern TLC
Authors:
Yuping Wang
,
Dongyuan Wang
,
Jie Wang
,
Zhili Xiong
,
Hongxia Zhang
,
Gaohong She
,
Jian Li
, and
Shengtao Xiao

A new AMD instrument made in our laboratory is described in this paper. The main advantages of the instrument are very low cost both of construction and in use. Compared with ascending development in conventional instruments, a laboratory-made horizontal sandwich chamber is used for development, and, with the help of a series of special accessories, no obvious mobile phase remains in the distributor after each step; this saves a large amount of solvent. All the components of the instrument are easy to obtain, so the average worker in a chemical laboratory could construct all the instrument except the control unit. An application of the instrument is described; the results obtained were satisfactory.

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Abstract  

With the low permeability and high swelling property, Gaomiaozi (GMZ) bentonite is regarded as the favorable candidate backfilling material for a potential repository. The diffusion behaviors of HTO in GMZ bentonite were studied to obtain effective diffusion coefficient (D e) and accessible porosity (ε) by through- and out-diffusion experiments. A computer code named Fitting for diffusion coefficient (FDP) was used for the experimental data processing and theoretical modeling. The D e and ε values were (5.2–11.2) × 10−11 m2/s and 0.35–0.50 at dry density from 1,800 to 2,000 kg/m3, respectively. The D e values at 1,800 kg/m3 was a little higher than that of at 2,000 kg/m3, whereas the D e value at 1,600 kg/m3 was significantly higher (approximately twice) than that of at 1,800 and 2,000 kg/m3. It may be explained that the diffusion of HTO mainly occurred in the interlayer space for the highly compacted clay (dry density exceeding 1,300 kg/m3). 1,800 and 2,000 kg/m3 probably had similar interlayer space, whereas 1,600 kg/m3 had more. Both D e and ε values decreased with increasing dry density. For compacted bentonite, the relationship of D e and ε could be described by Archie’s law with exponent n = 4.5 ± 1.0.

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Abstract  

A ternary binuclear complex of dysprosium chloride hexahydrate with m-nitrobenzoic acid and 1,10-phenanthroline, [Dy(m-NBA)3phen]2·4H2O (m-NBA: m-nitrobenzoate; phen: 1,10-phenanthroline) was synthesized. The dissolution enthalpies of [2phen·H2O(s)], [6m-HNBA(s)], [2DyCl3·6H2O(s)], and [Dy(m-NBA)3phen]2·4H2O(s) in the calorimetric solvent (VDMSO:VMeOH = 3:2) were determined by the solution–reaction isoperibol calorimeter at 298.15 K to be
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\Updelta_{\text{s}} H_{\text{m}}^{\theta }$$ \end{document}
[2phen·H2O(s), 298.15 K] = 21.7367 ± 0.3150 kJ·mol−1,
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\Updelta_{\text{s}} H_{\text{m}}^{\theta }$$ \end{document}
[6m-HNBA(s), 298.15 K] = 15.3635 ± 0.2235 kJ·mol−1,
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\Updelta_{\text{s}} H_{\text{m}}^{\theta }$$ \end{document}
[2DyCl3·6H2O(s), 298.15 K] = −203.5331 ± 0.2200 kJ·mol−1, and
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\Updelta_{\text{s}} H_{\text{m}}^{\theta }$$ \end{document}
[[Dy(m-NBA)3phen]2·4H2O(s), 298.15 K] = 53.5965 ± 0.2367 kJ·mol−1, respectively. The enthalpy change of the reaction was determined to be
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\Updelta_{\text{r}} H_{\text{m}}^{\theta } = 3 6 9. 4 9 \pm 0. 5 6 \;{\text{kJ}}\cdot {\text{mol}}^{ - 1} .$$ \end{document}
According to the above results and the relevant data in the literature, through Hess’ law, the standard molar enthalpy of formation of [Dy(m-NBA)3phen]2·4H2O(s) was estimated to be
\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $$\Updelta_{\text{f}} H_{\text{m}}^{\theta }$$ \end{document}
[[Dy(m-NBA)3phen]2·4H2O(s), 298.15 K] = −5525 ± 6 kJ·mol−1.
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Plant-plant interaction plays a key role in regulating the composition and structure of communities and ecosystems. Studies of plant-plant interactions in forest ecosystems have mainly concentrated on growth effects of neighboring plants on target trees. Physiological effects of neighboring plants on target trees, in particular understorey effects on physiology of overstorey trees, have received less attention. It is still unclear what is the physiological mechanisms underlying positive growth effects of understorey removal, although understorey removal has been applied to improve the wood production for hundreds of years worldwide. Only 17.5% of published works dealt with understorey-overstorey interactions and only a few of those researched the understorey effects on the physiology of overstorey trees. Case studies indicated that overstorey Abies faxoniana trees grown with different understorey shrubs showed significantly different levels of tissue nitrogen and mobile carbohydrates. Removal experiment showed that nitrogen and mobile carbohydrates concentrations in Cunninghamia lanceolata trees grown in the absence of understorey shrubs differed significantly (pure stand > mixture) with those in trees grown in the presence of understorey shrubs, in particular during the dry season. This review highlighted that the neighboring woody plants affect Cand N-physiology in overstorey trees. These effects may be mainly resulted from underground competition for soil water rather than for other resources as the effects were more pronounced during the dry season. The present review suggests that positive effects of neighboring removal (e.g., understorey removal, thinning) on overstorey trees can be expected more rapidly and strongly in stressful area (e.g., low rainfall, nutrient-poor site) than in areas with optimal growth conditions. Hence, ecophysiology-based management strategies for dealing with neighboring plants in forest ecosystems should take into account: 1) site conditions, 2) timing, duration and frequency of management practices, and 3) species-specific properties and other aspects such as biodiversity conservation and soil erosion.

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