MICROCHIMICA ACTA
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2020
·Vol. 187
·期 2
·1-9
·
IF 6.232
Hu Peng,Zhu Xiaoming,Luo Xiaohui,Hu Xiaofeng,Ji Liudi
The authors describe a novel electrochemical determination method for bisphenol A (BPA) based on the electrosynthesised Cu-BTC (H 3 BTC: trimesic acid) films. Using H 3 BTC as the ligand, Cu(NO 3 ) 2 as the precursor of copper ions, and triethylamine hydrochloride (Et 3 NHCl) as the probase source, Cu-BTC films were directly deposited on glassy carbon electrode (GCE) surface via cathodic electrochemical reduction under −1.30 V. Considering the electrocatalytic activity of metal center Cu 2+ , Cu-BTC films were applied to construct the electrochemical determination platform for BPA. Chronocoulometry and electrochemical impedance spectroscopy were used to study the signal enhancement mechanism. The determination conditions were optimized. As a result, a sensitive electrochemical method was constructed for BPA. The peak currents, best measured at voltage of 0.496 V vs. SCE (KCl saturated calomel reference electrode), increase linearly in the range from 5.0 to 2000 nM. The value of determination limit is 0.72 nM. The proposed method was successfully applied to determine BPA in spiked urine, spiked waste water samples and plastic products. The results were in good agreement with those obtained for the same samples by high-performance liquid chromatography (HPLC).
Schematics for the construction of electrochemical determination for bisphenol A.
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CELLULOSE
·
2020
·Vol. 27
·期 6
·3427-3442
·
IF 4.21
Liu Xiao-hui,Ding Chen,Peng Bo,Ren Yuan-lin,Cheng Bo-wen,Lin Sheng-gen,He Ju,Su Xiao-wei
In this paper, a simple and facile polyol sorbitol was employed to design and synthesize a novel flame retardant containing phosphorus and nitrogen by the reaction of sorbitol with phosphoric acid and urea. The obtained sorbitol-based flame retardant was then used to treat lyocell fibers by a pad-dry-cure procedure. Formaldehyde and other harmful substances were not used during the preparation of flame retardant and modified fibers. For this strategy, only water is used as solvent, and the conditions are mild, safe and environmentally friendly. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses show that the sorbitol-based flame retardant was successfully grafted onto lyocell fibers. Scanning electron microscopy analyses show that the surface morphology of the treated fibers remained unchanged. Thermogravimetric analyses imply that the residue of the treated fibers increases considerably. Vertical combustion and limit oxygen index results indicate that the treated fibers possess excellent flame retardant and durable properties. Based on the results of pyrolysis gas chromatography–mass spectrometry, thermogravimetric-infrared and Raman spectroscopy, the flame retardant operates in condensed phase and gas phase during burning of treated fibers.
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APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2020
·Vol. 104
·期 11
·4927-4943
·
IF 3.53
Deng Pengjun,Meng Chunyu,Wu Yan,Xu Jie,Tang Xiaoqing,Zhang Xuecheng,Xiao Yazhong,Wang Xiaotang,Fang Zemin,Fang Wei
A novel β -glucosidase, BglD1 with high β -galactosidase and transglycosidation activities, was screened and cloned from the deep-sea bacterium Bacillus sp. D1. BglD1 exhibited the maximal β -glucosidase and β -galactosidase activities at 55–60 °C and pH 5.5–6.0. The enzyme maintained approximately 50% of its original activity at 35 °C and pH 6.0 after 120-h incubation. When applied to synthesize galacto-oligosaccharides (GOS), BglD1 generated 118.3 g/L GOS (33.8% (w/w)) from 350 g/L lactose, with trisaccharide Gal- β (1 → 3)-Lac and disaccharide Gal- β (1 → 4)-Gal as the main components. Furthermore, BglD1 could hydrolyze lactose in milk and produce GOS simultaneously. Using milk as the substrate, BglD1 hydrolyzed 88.5% lactose and produced 3.3 g/L GOS after incubation at 30 °C for 1 h. To improve the transglycosidation activity, a mutant BglD1:E224T was generated based on the semi-rational design. The GOS yield of BglD1:E224T was 11.5% higher than that of BglD1 when using lactose solution as the substrate. Thus, BglD1 and the mutant could be used as beneficial alternatives of the existing β -galactosidases for the production of GOS.
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KOREAN JOURNAL OF CHEMICAL ENGINEERING
·
2020
·Vol. 37
·期 4
·597-603
·
IF 2.69
Chen Shuai,Zhou Wei,Liu Mingjun,Zhao Guangbo,Cao Qingxi,Zhao Bojun,Kou Kaikai,Gao Jihui
Oxidation of coal under mild conditions is effective not only to understand the macromolecular network structure of coal but also to produce useful chemicals, allowing more efficient application of coal resources. In this work, the mild oxidation of Zhundong subbituminous coal (ZS) by Fe 2+ /H 2 O 2 system was carried out under various conditions, including [Fe 2+ ]/[H 2 O 2 ] molar ratio, temperature, H 2 O 2 concentration and oxidation time. The liquid oxidation products were analyzed using gas chromatography/mass spectrometry (GC/MS), and the chemical structure changes were studied using Fourier transform infrared spectroscopy (FTIR). The results suggest that the oxidation efficiency of ZS with H 2 O 2 is enhanced with the aid of Fe 2+ . The optimum conditions were determined to be [Fe 2+ ]/[H 2 O 2 ] molar ratio of 0.00453, H 2 O 2 concentration of 3mol/L, 60 oC and 4 h according to the oxidation conversion rate. In total, 25 compounds were identified, which could be categorized as six group components. Most of them are valuedadded chemicals, and the content of benzene carboxylic acids is the highest among them, making up 29.99% of all group components in total relative content (TRC). -CH 2 - should be primary bridge connecting the aromatic rings, and alkylene chains linking three aromatic rings are abundant in ZS.
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INTERNATIONAL UROLOGY AND NEPHROLOGY
·
2020
·Vol. 52
·期 7
·1227-1234
·
IF 1.843
Wang Zhenghao,Bai Yunjin,Wang Jiahao,Wang Jia
Objective To investigate the effect of α-lipoic acid (α-LA) in the prevention and treatment of ethylene glycol-induced calcium oxalate deposition in a rat model and preliminary exploration of the mechanism. Methods Sixty male Wistar rats were divided randomly and equally into six groups including two α-LA prevention groups, two α-LA therapeutic groups, one controlled group and one intervention group. Besides controlled group, other group received 1% glycol solution and 2 ml 2% ammonium chloride for 4 weeks as a stone inducer. The prevention groups received 0.1 and 0.2 mg/kg body weight/day/rat α-LA as food supplement during inducing stone and therapeutic groups received 0.1 and 0.2 mg/kg body weight/day/rat α-LA for 4 weeks after 4 weeks stone inducing. Results The volume of urine, the pH and magnesium levels in the preventive and therapeutic groups were higher in a dose-independent manner ( p < 0.05), and urinary calcium was lower ( p < 0.05). Antioxidant stress enzyme activity (glutathione, superoxide dismutase, catalase) in serum and kidney homogenates in the preventive and therapeutic groups underwent significant regeneration ( p < 0.05) and malondialdehyde levels and the production of free radical moieties decreased. Pathological observation demonstrated that there was deformation due to renal tubular expansion in the control group, greater visible inflammatory cell infiltration into the interstitial spaces and partial destruction of the glomerular structures. α-lipoic acid improved the lesions to varying degrees. The extent of crystal deposition was lower in the preventive and therapeutic groups compared with the control group ( p < 0.05). Conclusion The present study indicated that α-LA provides both preventive and therapeutic effects against the deposition of calcium oxalate crystals in rats.
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MICROCHIMICA ACTA
·
2020
·Vol. 187
·期 4
·1-9
·
IF 6.232
Guo Ruya,Huang Fengchun,Cai Gaozhe,Zheng Lingyan,Xue Li,Li Yanbin,Liao Ming,Wang Maohua,Lin Jianhan
A colorimetric immunosensor was developed for the determination of Salmonella Typhimurium using rotating magnetic separation, gold nanorod (GNR) indication, and click chemistry amplification. The target bacteria were first separated from large-volume sample using a rotating magnetic field and a small amount (50 μg) of immunomagnetic nanoparticles (MNPs), resulting in the forming of magnetic bacteria. Then, the magnetic bacteria were conjugated with catalase (CAT)-labeled antibodies, which were synthesized using trans-cyclooctene / 1,2,4,5-tetrazine click chemistry reaction, resulting in the forming of enzymatic bacteria. Then the CATs on the enzymatic bacteria were used to decompose an excessive amount of hydrogen peroxide (H 2 O 2 ), the remaining H 2 O 2 was mixed with horseradish peroxidase to etch the GNRs, resulting in color change and absorbance peak shift of the GNRs. Finally, the peak shift was measured and analyzed for the quantitative determination of target bacteria. This immunosensor was able to detect Salmonella Typhimurium with a linear range of 10 1 –10 5 CFU mL −1 in 3 h with a low detection limit of 35 CFU mL −1 . The mean recovery for Salmonella Typhimurium in spiked chicken samples was 109%.
Schematic representation of a colorimetric immunosensor for the determination of Salmonella Typhimurium as low as 35 CFU mL −1 using rotating magnetic separation of Salmonella from a large-volume sample, click chemistry reaction of catalase with antibodies for signal amplification, and HRP-mediated gold nanorod etching for result indication.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2020
·Vol. 31
·期 11
·8220-8229
·
IF 2.22
Zhang Gaoyu,Sang Laifa,Xu Guogang,Dou Yajie,Wang Xinzhen
Meso-porous SnO 2 fibers were prepared via hydrothermal method, and natural silk was used as bio-template. Au nanoparticles served as the sensitizer were prepared on the surface of these SnO 2 fibers to further enhance the properties of gas sensing. Results show that these Au-modified products presented high surface area of 168.66 m 2 /g and meso-porous structure, and these fibers were composed of nanosized SnO 2 and Au particles with the size of about 7 ± 0.5 nm and 5 ± 0.5 nm, respectively. Gas sensing properties of these synthesized pristine products and Au-loaded fibers were investigated. Results show that these Au-modified SnO 2 fibers exhibited remarkably enhanced sensing performance to n -butanol with high response, good selectivity and good stability. The gas sensing mechanism was discussed from the effects of meso-porous structure, high surface area and Au nanoparticle catalytic activity.
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FISH PHYSIOLOGY AND BIOCHEMISTRY
·
2020
·Vol. 46
·期 4
·1207-1218
·
IF 2.249
Deng Dapeng,Yan Xiao,Zhao Wenli,Qin Chaobin,Yang Guokun,Nie Guoxing
Glucose transporter 2 ( glut2 ) has been studied in mammals, aves, and several fish, while the comparative studies of glut2 in common carp are still lacking. In this study, glut2 was firstly isolated and characterized from the liver of common carp. The full-length cDNA of glut2 was 2351 bp with an open reading frame (ORF) of 1512 bp, encoding 503 amino acids. Alignment of glut2 amino acid sequences from different species revealed that common carp glut2 showed higher sequence identity with teleosts, and lower homology with mammals and amphibians. Tissue distribution demonstrated that glut2 mRNA level was mainly expressed in liver, foregut, and midgut. To investigate the actions of glut2 on glucose metabolism, the level of glut2 mRNA was detected after intraperitoneal injection of glucose, human insulin and glucagon (100 ng/g), respectively. Following glucose administration, glut2 gene expression was significantly upregulated at 3 h in the foregut. However, no change was found in hepatic glut2 mRNA level, indicating that glut2 may have a role in intestinal glucose uptake rather than in the liver. Following insulin treatment, the expression of glut2 was markedly downregulated at 3 h and 6 h in the liver, and at 3 h in the foregut, respectively. Furthermore, glut2 mRNA expression was unaffected by glucagon injection in the liver and foregut. These results suggested that the expression of glut2 regulated by pancreatic hormones was different. Taken together, our studies firstly revealed the structure of the glut2 gene and its potential functions in glucose metabolism of common carp.
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CHEMICAL PAPERS
·
2020
·Vol. 74
·期 9
·2875-2882
·
IF 1.68
Gong Yilu,Shao Tantan,Chen Xiaolong,Cao Shusen,Chen Lijun
The silicone modified acrylate dispersion was successfully prepared by semi-continuous seed emulsion polymerization, in which methyl methacrylate (MMA) was used as a hard monomer, butyl methacrylate (BA)was used as a soft monomer, and a double bond-containing polymerizable emulsifier ammonium allyloxtmethylate nonylphenol ethoxylates sulfate (DNS-86)and potassium persulfate (KPS)were utilized as emulsifiers and initiators, respectively. A functional monomer, benzyl methacrylate (BZMA), and a modified monomer, vinyltriethoxysilane (VTES), were introduced into the base dispersion. The factors, which have an influence on emulsion polymerization performance, were optimized. At the same time, the dispersions prepared with conventional emulsifiers and polymerizable emulsifiers were compared under the same conditions. The structure and properties of the synthetic dispersion were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and contact angle (CA). The results showed that the optimum preparation conditions of the dispersion are as follows: The amount of emulsifier was 3%, the amount of initiator was 0.5%, main monomer ratio was 1:1, the amount of functional monomer BZMA and VTES was 3%, respectively. The dispersion obtained by using DNS-86 had better thermal stability, chemical stability and the dispersion was uniformly blue, which represented small particle size. After modification, the film showed higher hydrophobicity.
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Protein & Cell
·
2020
·Vol. 11
·期 4
·267-285
·
IF 10.164
Xu Gang,Ding Zhaozhao,Lu Qiang,Zhang Xiaoyi,Zhou Xiaozhong,Xiao Liying,Lu Guozhong,Kaplan David L
Gradient biomaterials are considered as preferable matrices for tissue engineering due to better simulation of native tissues. The introduction of gradient cues usually needs special equipment and complex process but is only effective to limited biomaterials. Incorporation of multiple gradients in the hydrogels remains challenges. Here, beta-sheet rich silk nanofibers (BSNF) were used as building blocks to introduce multiple gradients into different hydrogel systems through the joint action of crosslinking and electric field. The blocks migrated to the anode along the electric field and gradually stagnated due to the solution-hydrogel transition of the systems, finally achieving gradient distribution of the blocks in the formed hydrogels. The gradient distribution of the blocks could be tuned easily through changing different factors such as solution viscosity, which resulted in highly tunable gradient of mechanical cues. The blocks were also aligned under the electric field, endowing orientation gradient simultaneously. Different cargos could be loaded on the blocks and form gradient cues through the same crosslinking-electric field strategy. The building blocks could be introduced to various hydrogels such as Gelatin and NIPAM, indicating the universality. Complex niches with multiple gradient cues could be achieved through the strategy. Silk-based hydrogels with suitable mechanical gradients were fabricated to control the osteogenesis and chondrogenesis. Chondrogenic-osteogenic gradient transition was obtained, which stimulated the ectopic osteochondral tissue regeneration in vivo. The versatility and highly controllability of the strategy as well as multifunction of the building blocks reveal the applicability in complex tissue engineering and various interfacial tissues.
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Scientific Reports
·
2020
·Vol. 10
·期 1
·1-9
·
IF 3.998
Chen Jinxiang,Yang Jing,Ma Lanlan,Li Jun,Shahzad Nasir,Kim Chan Kyung
The antioxidant activities of 18 typical phenolic acids were investigated using 2, 2′-diphenyl-1-picrylhydrazyl (DPPH) and ferric ion reducing antioxidant power (FRAP) assays. Five thermodynamic parameters involving hydrogen atom transfer (HAT), single-electron transfer followed by proton transfer (SET-PT), and sequential proton-loss electron transfer (SPLET) mechanisms were calculated using density functional theory with the B3LYP/UB3LYP functional and 6–311++G (d, p) basis set and compared in the phenolic acids. Based on the same substituents on the benzene ring, -CH 2 COOH and -CH = CHCOOH can enhance the antioxidant activities of phenolic acids, compared with -COOH. Methoxyl (-OCH 3 ) and phenolic hydroxyl (-OH) groups can also promote the antioxidant activities of phenolic acids. These results relate to the O-H bond dissociation enthalpy of the phenolic hydroxyl group in phenolic acids and the values of proton affinity and electron transfer enthalpy (ETE) involved in the electron donation ability of functional groups. In addition, we speculated that HAT, SET-PT, and SPLET mechanisms may occur in the DPPH reaction system. Whereas SPLET was the main reaction mechanism in the FRAP system, because, except for 4-hydroxyphenyl acid, the ETE values of the phenolic acids in water were consistent with the experimental results.
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Frontiers of Chemical Science and Engineering
·
2020
·Vol. 14
·期 6
·1018-1028
·
IF 3.552
Zeng Jiehui,Zeng Jianxian,Zhou Hu,Liu Guoqing,Yuan Zhengqiu,Jian Jian
An ion-imprinted sorbent (IIP) was prepared by using Ni 2+ as template, 3-[2-(2-aminoethylamino) ethylamino] propyl-trimethoxysilane as functional monomer, and silica gel as carrier. The adsorption performance of IIP towards Ni 2+ was investigated. IIP showed a higher adsorption capacity than that of non-imprinted sorbent, and it also exhibited high selectivity for Ni 2+ in the presence of Cu 2+ and Zn 2+ ions. Then, IIP was used to form a dynamic membrane onto the surface of ceramic membrane for treatment of electroplating wastewater containing Ni 2+ . Compared with ceramic membrane, IIP dynamic membrane had much higher steady membrane flux, and also rejected Ni 2+ to obtain a lower concentration of Ni 2+ in the permeate fluid. Perhaps it is suitable for future practice applications.
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