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Peng H.,University of Georgia | Peng H.,Donghua University | Yang C.Q.,University of Georgia | Wang X.,Beijing Institute of Microchemistry | Wang S.,Donghua University
Industrial and Engineering Chemistry Research | Year: 2012

In this research, we studied cross-linking of cotton fabrics using the combination of itaconic acid (ITA) and sodium hypophosphite (NaH 2PO 2). ITA, a bifunctional carboxylic acid, was able to esterify cotton cellulose to form a single ester linkage, but it was not able to form cross-linking between two cellulose molecules. In the presence of NaH 2PO 2, the amount of ester formed on cotton fabric was increased substantially and the esterification temperature of ITA was reduced. Therefore, NaH 2PO 2 functioned as a catalyst for esterification of cotton by ITA. Moreover, we found that wrinkle resistance of the cotton fabric was significantly improved when cotton fabrics were treated with the combination of ITA and NaH 2PO 2.We also found that phosphorus was bound to the treated cotton fabric and that the increase in the wrinkle recovery angle of the treated fabric was correlated to the increase in the amount of phosphorus bound to cotton. All the data indicated that H-P-H of sodium hypophosphite probably reacts with the >C C< of two ITA molecules, which are also esterified with cellulose, thus forming a cross-linkage between the two cellulose molecules. The cotton fabrics treated with the ITA/NaH 2PO 2 system demonstrated a high level of durable press performance with significantly lower tensile strength loss than those treated with the formaldehyde-based dimethyloldihydroxyethyleneurea. © 2012 American Chemical Society.

Chen J.,Beijing Institute of Microchemistry | He T.,PLA Logistical Engineering University | He T.,Tsinghua University | Fan X.,Tsinghua University
Talanta | Year: 2012

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was thought to be unsuitable for the analysis of low-molecular-weight species since matrix peak noise made it difficult to identify analyte ions. In this study, MCM-41-type mesoporous silica nanoparticles (MSNs) were used as a matrix additive with saturated 2,5-dihydroxybenzoic acid (DHB) or α-cyano-4- hydroxycinnannic acid (CHCA) solution for the analysis of six peptides of a wide range molecular weight, Leu-Val, Phe-Val, Lue-Phe, bradykinin fragment 1-7, angiotensin II and ACTH fragment 18-39. It was shown that MSNs were capable of reducing matrix peaks with laser power lower than 34 of saturated DHB especially for low polarity analyte or CHCA especially for high polarity analyte with molecular weight less than 500 regardless of the analyte-to-matrix ratio. In addition, MSNs could suppress ionization of oligopeptide and polypeptide. The way MSN exerted its effect was supposed to be via attraction between surface silanol groups and the analyte. © 2012 Elsevier B.V.

Zhang C.,Beijing University of Chinese Medicine | Wang R.,Beijing University of Chinese Medicine | Liu B.,Beijing University of Chinese Medicine | Tu G.,Beijing Institute of Microchemistry
Magnetic Resonance in Chemistry | Year: 2011

A new sodium salt of anthraquinone named sodium emodin-1-O-β- gentiobioside, together with nine known compounds, viz. rubrofusarin-6-O-β- D-gentiobioside, chrysophanol-1-O-β-D-glucopyranosyl-(1-3)-β-D- glucopyranosyl-(1-6)-β-D-glucopyranoside, obtusifolin-2-O-β-D- glucopyranoside, aurantio-obtusin-6-O-β-D-glucopyranoside, physcion-8-O-β-D-glucopyranoside, 1-hydroxyl-2-acetyl-3,8-dimethoxy-6-O- β-D-apiofuranosyl-(1-2)-β-D-glucosylnaphthalene, toralactone-9-O- β-D-gentiobioside, aurantio-obtusin, rubrofusarin-6-O-β-D- apiofuranosyl-(1-6)-O-β-D-glucopyranoside, was isolated from the seeds of Cassia obtusifolia and its structure was elucidated by 1H and 13C NMR technique assisted with acid-alkali titration. The change of chemical shifts of sodium emodin-1-O-β-gentiobioside before and after acid-alkali titration was also characterized. Copyright © 2011 John Wiley & Sons, Ltd.

Liu C.-L.,Beijing University of Chemical Technology | Lv Q.,Beijing Institute of Microchemistry | Tan T.-W.,Beijing University of Chemical Technology
RSC Advances | Year: 2015

Isoprene (C5H8) is a key chemical ingredient for the production of synthetic rubber and plastic. Isoprene is commonly petro-chemically produced. Enabling sustainable microbial fermentation for isoprene production from potential biofuels is an attractive alternative to the original derivation. To this end, antisense RNA strategies, for redirection of weakening genes and control of metabolic pathways, were introduced to regulate the isoprene production. The isoprene titer, the intermediates of the methylerythritol 4-phosphate (MEP) pathway at the metabolic level and mRNA at the transcriptional level were all successfully affected as a consequence of simultaneous weakening of the farnesyl diphosphate synthase (ispA), octaprenyl diphosphate synthase (ispB) and undecaprenyl pyrophosphate synthase (ispU) of the MEP pathway in Escherichia coli BL21 (DE3). The finally obtained strain IAUB accumulated isoprene up to 16 mg L-1 in a flask culture, which was about eight times of what was achieved by the control strain Idi. Detailed knowledge about the mechanisms of the novel strategies may benefit the development of many other bio-derived products. © 2015 The Royal Society of Chemistry.

Zhang D.-W.,CAS Beijing National Laboratory for Molecular | Sun C.-J.,University of International Relations | Zhang F.-T.,CAS Beijing National Laboratory for Molecular | Xu L.,Beijing Institute of Microchemistry | And 2 more authors.
Biosensors and Bioelectronics | Year: 2012

An aptamer is an artificial functional oligonucleic acid, which can interact with its target molecule with high affinity and specificity. Enzyme linked aptamer assay (ELAA) is developed to detect cocaine using aptamer fragment/cocaine configuration based on the affinity interaction between aptamer fragments with cocaine. The aptasensor was constructed by cleaving anticocaine aptamer into two fragments: one was assembled on a gold electrode surface, while the other was modified with biotin at 3'-end, which could be further labelled with streptavidin-horseradish peroxidase (SA-HRP). Upon binding with cocaine, the HRP-labelled aptamer fragment/cocaine complex formed on the electrode would increase the reduction current of hydroquinone (HQ) in the presence of H 2O 2. The sensitivity and the specificity of the proposed electrochemical aptasensor were investigated by differential pulse voltammetry (DPV). The results indicated that the DPV signal change could be used to sensitively detect cocaine with the dynamic range from 0.1μM to 50μM and the detection limit down to 20nM (S/N=3). The proposed aptasensor has the advantages of high sensitivity and low background current. Furthermore, a new configuration for ELAA requiring only a single aptamer sequence is constructed, which can be generalized for detecting different kinds of targets by cleaving the aptamers into two suitable segments. © 2011 Elsevier B.V..

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