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  • Author or Editor: Dong Zhang x
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Abstract  

Differential elastic scattering cross sections for backscattering of 0.96–2.74 MeV protons incident on an aluminum layer covered by a gold layer deposited on a graphite crystal have been measured. The lowest proton energy in the experiment is in the Rutherford backscattering energy region. The measured cross sections are compared with the previous data and presented in graphical and tabular forms.

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Abstract  

The concentrations of up to 11 elements in subcellular fractions of human brain (normal and malignant tumor) have been determined by a combination of gradient centrifugation and INAA methods. Samples of human brain were homogenized in a glass homogenizer tube, the homogenate was separated into nuclei, mitochondrial, myelin, synaptosome fractions, and these fractions were then analyzed using the INAA method. The discussions of elemental subcellular distributions in human brain malignant tumor are presented in this paper.

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Abstract  

The sorption of 60Co(II) on γ-Al2O3 was conducted under various conditions, i.e., contact time, adsorbent content, pH, ionic strength, foreign ions, humic acid (HA), and temperature. Results of sorption data analysis indicated that the sorption of 60Co(II) on γ-Al2O3 was strongly dependent on pH and ionic strength. At low pH the sorption was dominated by outer-sphere surface complexation or ion exchange, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. The presence of different cation ions influenced 60Co(II) sorption, while the presence of different anion ions had no obvious influences on 60Co(II) sorption. The presence of HA decreased the sorption of 60Co(II) on γ-Al2O3. The sorption isotherms were simulated well with the Langmuir model. The thermodynamic parameters (ΔH 0 , ΔS 0 and ΔG 0 ) calculated from the temperature-dependent sorption isotherms indicated that the sorption of 60Co(II) on γ-Al2O3 was an endothermic and spontaneous process. Experimental results indicated that the low cost material was a suitable material in the preconcentration of 60Co(II) from large volumes of aqueous solutions.

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Abstract  

The sorption of Co(II) from aqueous solution on Na-rectorite was investigated under ambient conditions. Experiments were carried out as a function of contact time, solid content, pH, ionic strength, foreign ions, fulvic acid and temperature. The results indicated that the sorption of Co(II) was strongly dependent on pH. At low pH the sorption was dominated by outer-sphere surface complexation or ion exchange, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. The Langmuir, Freundlich and Dubinin–Radushkevich (D–R) models were used to simulate the sorption isotherms at three different temperatures. The thermodynamic data (∆G 0, ∆S 0, ∆H 0) were calculated from the temperature dependent sorption isotherms and the results suggested that the sorption process of Co(II) on Na-rectorite was spontaneous and endothermic. Experimental results indicate that Na-rectorite is a suitable adsorbent for preconcentration and solidification of Co(II) from large volumes of aqueous solutions.

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Abstract

Biomass pyrolysis can be divided into three stages: moisture evaporation, main devolatilization, and continuous slight devolatilization. This present study focuses on the heat and mass transfer characteristics of biomass in the first pyrolysis stage, which takes place in the range of room temperature to 150 °C. Thermalgravimetric experiments of rice husk and cotton stalk were performed by a synchronic thermal analyzer (TG/DSC). Four nonisothermal drying models were obtained from common isothermal drying models in order to describe the drying behavior of agricultural products. The moisture content of biomass decreased rapidly as the temperature increased and an apparent water loss peak was observed in the temperature range of 65–75 °C. DSC could be regarded as the superposition of three parts: heat flow from moisture evaporation, heat flow from the heat capacity of unevaporated moisture, and heat flow from the heat capacity of dry base biomass. The heat requirements for the dehydration of 1 kg rice husk and cotton stalk were 251 and 269 kJ, respectively. Nonisothermal drying models were evaluated based on the coefficient of determination (R 2) and reduced chi-square (χ2). Page model was found to be the best for describing the nonisothermal drying kinetics. The values of activation energy were determined to be 9.2 and 15.1 kJ/mol for rice husk and cotton stalk, respectively.

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Abstract  

This study characterized the removal of strontium from an aqueous solution via co-precipitation followed by microfiltration (CPMF) on a lab-scale. Sodium carbonate was used as the precipitating agent. Ferric chloride was added to a settler at a dosage of 20 mg/L to improve strontium removal, and it was added to a membrane separator at a dosage of 10 mg/L to reduce membrane fouling. The concentration of strontium in the raw water used in this study was about 5 mg/L. In two intermittent tests, where dosages of sodium carbonate were 2000 mg/L and 1000 mg/L, the mean decontamination factors (DFs) were 237 and 158 and the mean concentration factors (CFs) were 288 and 462, respectively. Although the mean DF value was lower when the sodium carbonate dosage was 1000 mg/L instead of 2000 mg/L, the rate at which the specific flux (SF) of the membrane declined decreased as the amount of the effluent treated increased. The problem of strontium release at the beginning of the operation was controlled by a continuous test in which the dosage of sodium carbonate still was 1000 mg/L and the other parameters were the same as in the other tests. The results showed that the mean DF and CF were 157 and 480, respectively.

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Abstract

Venetoclax is the first oral Bcl-2 inhibitor with high affinity targeting tumor cell apoptosis mechanism. In this study we developed a simple, sensitive and reliable LC–MS/MS method to determine venetoclax in children's hemolytic or lipemic samples. The method utilized an electrospray ion source and operated in multiple reaction monitoring mode. Venetoclax-d8 was used as an internal standard. Plasma samples were precipitated by acetonitrile containing 10% dimethyl sulfoxide and were separated by a Hypersil GOLD column (2.1 mm × 150 mm, 5 μm). The mobile phase consisted of acetonitrile-2 mM ammonium acetate (30:70, v/v) containing 0.4% formic acid. The quantification for venetoclax and venetoclax-d8 were m/z 868.1 → 636.1, m/z 876.1 → 644.1, respectively. The linear range was 10–2,000 ng mL−1 for venetoclax. The matrix in normal plasma, hemolytic or lipemic plasma had no significant effect on the detection results. The specificity, recovery and stability also met the acceptance criteria of guiding principles for the validation of biological sample quantitative analysis presented in the Chinese Pharmacopoeia (2015). As a result, this method is particularly suitable for determining venetoclax in hemolytic or lipemic samples from children with acute myeloid leukemia. The method, with the application of monitoring drug concentrations in pediatric patients, was successful.

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Abstract  

Atmospheric aerosols are generally collected on filters according to the International Monitoring System (IMS) designed in the Comprehensive Nuclear-Test-Ban Treaty (CTBT). More information could be revealed when the filter sample is pretreated rather than measured directly by g-ray spectrometer. Microwave-assisted extraction (MAE) is a suitable method that gives higher recoveries of elements from glass fibrous filters under different conditions. The results indicate that the MAE is a highly efficient and robust method for the treatment of glass fibrous filter samples. The recoveries of potential fission products from glass fibrous filter samples by microwave-assisted extraction meet the efficiency of the extraction by both aqua regia and 2% HCl.

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Abstract  

Bentonite was investigated to remove Ni(II) from aqueous solutions because of its strong sorption ability. Herein, bentonite was modified with sodium carboxymethylcellulose (CMC) and used as an adsorbent to remove Ni(II) from aqueous solutions. The results indicated that CMC-bentonite had higher sorption capacity than bare bentonite in the sorption of Ni(II) from aqueous solutions. Sorption of Ni(II) on CMC-bentonite was mainly dominated by ion exchange or outer-sphere surface complexation at low pH values, but by inner-sphere surface complexation or surface precipitation at high pH values. The thermodynamic data calculated from temperature dependent sorption isotherms indicated that the sorption of Ni(II) to CMC-bentonite hybrids was an spontaneous process and enhanced with increasing temperature.

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Abstract

Curcumin (CUR), a frequently-used food additive and flavorings, has been reported to be safe at a wide dose range. Bacillus subtilis (B. subtilis) is commonly found in soil and decomposing organic matter, and it was reported beneficial for humans when ingested. Up to now, there have been no contraindication of B. subtilis except for the avoidance of the drug combination with antibiotics, and the interaction of food and B. subtilis drug is blank. In this study, the interaction of CUR and B. subtilis was investigated. Microcalorimetry was applied to evaluate the effect of CUR on B. subtilis growth. By analyzing the main parameters extracted from the heat-flow power–time curves, it was concluded that CUR could inhibit the growth of B. subtilis, and the 50% inhibiting concentration (IC50) valued 109.9 μg mL−1. The results revealed that it is unreasonable to take CUR and B. subtilis at the same time, and it also provided a new way for the investigation of the interaction between food and drug. Meanwhile, this study indicated that the safety of CUR should be re-evaluated.

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