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Sun L.-T.,Polytechnic University of Mozambique | Zhang Y.-X.,Polytechnic University of Mozambique | Zhang P.-F.,Shaanxi Entry Exit Inspection and Quarantine Bureau
Wool Textile Journal | Year: 2013

It reported that the temperature influence on the structure and properties of silk fibers at present situation. With the treatment in the high temperature for silk fiber, β-sheet structure relative content decreased, while the α-helix and random coil structure had a tendency to rise, high temperature had great influence on fiber inter-fibrillar supramolecular structure, formed apparent stripes and groove structure on the fiber surface, yellow index increased, strength and elongation percentage decreased. With the low temperature freezing treatment, the water molecules of crystallization in fresh cocoon, made the bonding performance between the silk sericin become weaken, Cocoon reelability percentage increased, appeared microporous structure on the fiber surface after freezing, so that it made the fiber surface activity increase, the moisture absorption and antibacterial ability increase. With treatment for silk fabrics in the freezing, the permeability of the fabric was increased obviously, but the strength had a downward trend along with the time prolonged.


Huang J.,Shaanxi Entry Exit Inspection and Quarantine Bureau | Huang J.,Xi'an University of Technology | Kong X.,Shaanxi Entry Exit Inspection and Quarantine Bureau | Yao B.,Xi'an University of Technology | And 3 more authors.
Chinese Journal of Chromatography (Se Pu) | Year: 2011

A method by using a modified QuEChERS (quick, easy, cheap, effective, rugged and safe) and gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS) was established to analyze 88 pesticide residues in cranberry plant extract. The sample was extracted with acetone-hexane (1:1, v/v) containing 1% acetic acid, then cleaned-up by ethylenediamine-N-propyl silyl (PSA) and graphite carbon (GCB). The extract was determined by GC-MS/MS in multi-reaction monitoring (MRM) mode, and external standard method was applied to quantified the pesticides. All the 88 pesticides showed good linearity in the range of 0.001 - 0.2 mg/L, and the limits of quantification (LOQs, S/N≥10) were all less than 31.5 μg/kg. The average recoveries of all the pesticides were in the range of 71.4% to 116.6% at three spiked levels of 5, 25 and 50 μg/kg in cranberry plant extract, with the relative standard deviations (RSDs) of 2.4% - 16.9%. The results demonstrated that this method is simple, rapid and suitable for the determination of 88 pesticide residues in cranberry plant extract. The analytical sensitivity and accuracy can meet the requirements of multiple pesticide residue analysis.


Wang Y.,Northwest University, China | Yin X.,Northwest University, China | Yin X.,Key Laboratory of Plant Nutrition and the Agri Environment in Northwest China | Sun H.,Northwest University, China | And 2 more authors.
Chemical Speciation and Bioavailability | Year: 2016

Vanadium, a hazardous pollutant, has been frequently detected in soil and groundwater, however, its transport behavior in porous media were not clearly understood. In this study, the effects of solution pH, ionic strength (IS) and the effect of clay mineral on the transport of vanadium in saturated porous media were investigated. Laboratory experiments using a series of columns packed with quartz sand were carried out to explore the retention and transport of vanadium with a range of ionic-strength (0.001-0.1 M) and pH (4-8) and two different types of clay minerals montmorillonite and kaolinite. Results of the breakthrough experiments showed that vanadium was highly mobile in the saturated porous media. The increase in pH rendered a higher transport of vanadium in saturated porous media. The study also indicated an easier transfer of vanadium with an increase in IS. Montmorillonite enhanced the mobility of vanadium in the column when compared to kaolinite. A mathematical model based on advectiondispersion equation coupled with equilibrium and kinetic reactions was used to describe the retention and transport of vanadium in the columns very well. © 2016 The Author(s).


Zhang J.,Northwest University, China | Liu Y.-F.,Northwest University, China | Bo L.,Northwest University, China | Qiao C.-A.,Shaanxi Entry Exit Inspection and Quarantine Bureau
Journal of Applied Polymer Science | Year: 2011

Dopamine (DA) was covalently linked via succinic anhydride spacers to poly(ethylene glycol)s (PEGs) with average molecular weights of 4000 (PEG4000), 6000 (PEG6000), and 10,000 (PEG10000). The chemical modification of the PEGs was conducted by a two-step protocol: (1) the preparation of PEG having carboxylic end groups and (2) the synthesis of PEG4000-DA, PEG6000-DA, and PEG10000-DA. The controlled drug-release studies were performed in pH 1.1, 7.4, and 9.0 buffer solutions, The results demonstrate that under the same conditions, the rate of hydrolysis for PEG10000-DA was the slowest among three prodrugs, and a greater amount of DA could be detected being released from the prodrug matrices in the presence of α-chymotrypsin in a buffer solution with pH 8.0. Also, these novel prodrugs could slowly release the active drug molecules and improve the pharmacokinetics of DA. © 2011 Wiley Periodicals, Inc.


Fu C.,Shaanxi Entry Exit Inspection and Quarantine Bureau | Li Y.,Shaanxi Entry Exit Inspection and Quarantine Bureau | Ling L.,Shaanxi Entry Exit Inspection and Quarantine Bureau | Wu Z.,University of Sichuan | Jiang W.,University of Sichuan
Journal of the Chinese Cereals and Oils Association | Year: 2014

In the paper, a rapid analysis method combining with methyl esterification reaction of aliphatic acid and gas chromatography detection of aliphatic acid methyl ester (FAME) was established to determine the content of varied aliphatic acid triglyceride ingredient in oil with tetrahydrofuran (THF) as cosolvent in methyl esterification process. The adding of cosolvent, THF, could enhance the intermiscibility between aliphatic acid and methanol during reaction; increase the reaction rate and oil conversion promote the reaction speed of methyl esterification process and accuracy of FAME analysis. The results showed that the new combined method had a good linear relationship and high degree of precision compared to traditional analysis method. The adding of THF had no affect on the analysis of FAME via gas chromatography. The relative standard deviations of such rapid combined method were no more than 2.02%, and the average addition standard recoveries of three typical aliphatic acid methyl esters, oleic acid methyl ester, stearic acid methyl ester, and palmitic acid methyl ester were from 96.14% to 103.45%. The conversion of three typical triglyceride, oleic acid triglyceride, stearic acid triglyceride and palmitic acid triglyceride could reach over 95% in methyl esterification process. The actual aliphatic acid ingredient could be determined rapidly and accurately via the combined analysis method.


Jiang W.,University of Sichuan | Zou H.,University of Sichuan | Fu C.,Shaanxi Entry Exit Inspection and Quarantine Bureau | Lei J.,University of Sichuan | And 2 more authors.
Industrial and Engineering Chemistry Research | Year: 2014

Biodiesel is a promising alternative biofuel, but the treatment of wastewater containing alkali catalyst and glycerol discharged from the washing unit operation increases the cost significantly. Here a novel continuous biodiesel production process with trace-amount alkali as the catalyst under the methanol subcritical condition was proposed and investigated. The optimal operation conditions of preliminary batch reaction experiment are temperature of 200 °C, catalyst concentration of 513 mg/kg, reaction time of 38 min, molar ratio of methanol to oil of 11.9:1, and system pressure of 1.5 MPa. The one-step conversion of raw oil in a batch reactor can reach up to 85.5%. The alkali residue in the biodiesel product can be further reduced by removing the methanol and washing by glycerol instead of by acid or water. The optimal weight ratio of glycerol to biodiesel is 1.5:1, and the residual alkali in the final ester product is about 4.6 mg/kg. The simulation and bench scale continuous experiment based on the optimal batch operation parameters confirmed that the biodiesel produced by the process is qualified well up to the Chinese standard of biodiesel, and the K+ concentration in biodiesel was less than 3.0 mg/kg. The economic evaluation showed that this new process is more economically feasible than the traditional processes. © 2014 American Chemical Society.


Zhang L.,Shaanxi Entry Exit Inspection and Quarantine Bureau | Kong X.,Shaanxi Entry Exit Inspection and Quarantine Bureau | He Q.,Shaanxi Entry Exit Inspection and Quarantine Bureau | Zhang L.,Xian Supervision and Inspection Institute of Product Quality | Li J.,Shaanxi Entry Exit Inspection and Quarantine Bureau
Chinese Journal of Chromatography (Se Pu) | Year: 2014

A Turbo flow-ultra performance liquid chromatography-tandem mass spectrometry (TF-UPLC-MS/MS) method was developed for the determination of five imidazole pesticides (imazapyr, triazoxide, rabenzazole, prochloraz and fenamidone) in fruits. The fruit samples were dissolved in saturated sodium chloride solution and extracted by acetonitrile. After the acetonitrile layer was evaporated and redissolved with acetonitrile-water (1:1, v/v), the fruit samples were analyzed by TF-UPLC-MS/MS. The main factors influencing the purification effi-ciency including the TF column, mobile phase, elution solution and elution rate were opti-mized. Under the optimized experimental conditions, the analytes were purified by Turbo flow C18 column (50 mm×1. 0 mm) and separated on a Hypersil GOLD aQ column (100 mm ×2. 1 mm) using the mobile phases of acetonitrile and 5 mmol/L ammonium acetate (containing 0. 1% (v/v) formic acid) aqueous solution with gradient elution. The compounds were detected by selective reaction monitoring (SRM) via positive electrospray ionization (ESI+). The linear range of the method ranged from 0. 007 5 to 0. 75 mg/L for all the five imidazole pesticides, with the correlation coefficients (r2) greater than 0. 99. The limits of quantification were 0. 005 mg/kg for all the five imidazole pesticides. The recoveries were in the range from 71.2% to 122. 4% at the spiked levels of 0. 005, 0. 01, 0. 05 and 0. 5 mg/kg with the relative standard deviations ranging from 0. 5% to 8. 9% in actual samples. The results indicate that the developed method is simple, efficient and precise, and can be a reliable technique for the determination of the five imidazole pesticides in fruit samples.


Zou Y.,Shaanxi Entry Exit Inspection and Quarantine Bureau
Zhong yao cai = Zhongyaocai = Journal of Chinese medicinal materials | Year: 2012

To study the chemical constituents from Astilbe myriantha. The constituents were isolated and purified by column chromatography methods and recrystallization. Their structures were identified on the basis of physiochemical properties and special analysis. Ten compounds were isolated from 95% ethanol extract of Astilbe myriantha and their structures were identified as: beta-sitosterol (1), methyl p-hydroxy benzoate (2), ferulic acid (3), bergenin (4), gallic acid (5), (+)-catechin (6), 3beta-acetoxy-6beta-hydroxyolean-12-en-27-oic acid (7), 3beta-hydroxyolean-12-en-27-oic acid (8),3beta,6beta-dihydrolean-12-en-27-oic acid (9) and 3beta-hydroxyurs-12-en-27-oic acid (10). Compounds 1-7 are isolated from this plant for the first time.


PubMed | Northwest Agriculture and Forestry University, Shaanxi Entry Exit Inspection and Quarantine Bureau and Mansoura University
Type: | Journal: Chemosphere | Year: 2016

Batch sorption kinetics and isothermal characteristics of V(V) were investigated on three natural soil colloids (manual loessial soil colloid (MSC), aeolian sandy soil colloid (ASC), and cultivated loessial soil colloid (CSC)) under various solution pH and ionic strength (IS) conditions. Colloids were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FTIR). AFM micrographs showed CSC with an aggregated shape with larger particle diameter as compared with ASC and MSC. XRD spectra revealed the presence of different minerals in natural soil colloids including biotite, kaolinite, calcite and quartz, which might contribute to sorption process. The sorption ability decreased with increase of colloidal particle size. The sorption was mainly attributed to complexation by active carboxylate and alcohol groups of colloidal components. Sorption kinetics and isotherms of V(V) onto natural soil colloids were best fitted with Pseudo-second-order and Freundlich models. Langmuir model indicated that sorption capacity of MSC and ASC was comparable (285.7 and 238.1mgg


PubMed | Shaanxi Entry Exit Inspection and Quarantine Bureau
Type: Journal Article | Journal: Zhong yao cai = Zhongyaocai = Journal of Chinese medicinal materials | Year: 2012

To study the chemical constituents from Astilbe myriantha.The constituents were isolated and purified by column chromatography methods and recrystallization. Their structures were identified on the basis of physiochemical properties and special analysis.Ten compounds were isolated from 95% ethanol extract of Astilbe myriantha and their structures were identified as: beta-sitosterol (1), methyl p-hydroxy benzoate (2), ferulic acid (3), bergenin (4), gallic acid (5), (+)-catechin (6), 3beta-acetoxy-6beta-hydroxyolean-12-en-27-oic acid (7), 3beta-hydroxyolean-12-en-27-oic acid (8),3beta,6beta-dihydrolean-12-en-27-oic acid (9) and 3beta-hydroxyurs-12-en-27-oic acid (10).Compounds 1-7 are isolated from this plant for the first time.

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