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Genomic and metabolomic analysis of with enhanced poly--glutamic acid production through atmospheric

《化学科学与工程前沿（英文）》 2022年 第16卷 第12期   页码 1751-1760 doi: 10.1007/s11705-022-2211-x

摘要： Poly-γ-glutamic acid is an extracellular polymeric substance with various applications owing to its valuable properties of biodegradability, flocculating activity, water solubility, and nontoxicity. However, the ability of natural strains to produce poly-γ-glutamic acid is low. Atmospheric and room temperature plasma was applied in this study to conduct mutation breeding of Bacillus licheniformis CGMCC 2876, and a mutant strain M32 with an 11% increase in poly-γ-glutamic acid was obtained. Genome resequencing analysis identified 7 nonsynonymous mutations of ppsC encoding lipopeptide synthetase associated with poly-γ-glutamic acid metabolic pathways. From molecular docking, more binding sites and higher binding energy were speculated between the mutated plipastatin synthase subunit C and glutamate, which might contribute to the higher poly-γ-glutamic acid production. Moreover, the metabolic mechanism analysis revealed that the upregulated amino acids of M32 provided substrates for glutamate and promoted the conversion between L- and D-glutamate acids. In addition, the glycolytic pathway is enhanced, leading to a better capacity for using glucose. The maximum poly-γ-glutamic acid yield of 14.08 g·L–1 was finally reached with 30 g·L–1 glutamate.

关键词： ARTP mutagenesis     Bacillus licheniformis     poly-γ-glutamic acid     metabolomics    

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Effect of polyethylene glycol on the crystallization, rheology and foamability of poly(lactic acid) containing

《化学科学与工程前沿（英文）》 2023年 第17卷 第12期   页码 2074-2087 doi: 10.1007/s11705-023-2342-8

摘要： In this study, the rheological properties, crystallization and foaming behavior of poly(lactic acid) with polyamide 6 nanofibrils were examined with polyethylene glycol as a compatibilizer. Polyamide 6 particles were deformed into nanofibrils during drawing. For the 10% polyamide 6 case, polyethylene glycol addition reduced the polyamide 6 fibril diameter from 365.53 to 254.63 nm, owing to the smaller polyamide 6 particle size and enhanced interface adhesion. Rheological experiments revealed that the viscosity and storage modulus of the composites were increased, which was associated with the three-dimensional entangled network of polyamide 6 nanofibrils. The presence of higher aspect ratio polyamide 6 nanofibrils substantially enhanced the melt strength of the composites. The isothermal crystallization kinetics results suggested that the polyamide 6 nanofibrils and polyethylene glycol had a synergistic effect on accelerating poly(lactic acid) crystallization. With the polyethylene glycol, the crystallization half-time reduced from 103.6 to 62.2 s. Batch foaming results indicated that owing to higher cell nucleation efficiency, the existence of polyamide 6 nanofibrils led to a higher cell density and lower expansion ratio. Furthermore, the poly(lactic acid)/polyamide 6 foams exhibited a higher cell density and expansion ratio than that of the foams without polyethylene glycol.

关键词： poly(lactic acid)     foaming     microfibrillation     rheological property     crystallization    

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Controlled drug release of 5-amino salicylic acid by poly(2-hydroxyethylmethacrylate) grafted agar

G. Usha RANI,Kartick Prasad DEY,Srijita BHARTI,Sumit MISHRA

《化学科学与工程前沿（英文）》 2014年 第8卷 第4期   页码 465-470 doi: 10.1007/s11705-014-1452-8

摘要： The utilization of poly (2-hydroxyethylmethacrylate) grafted agar (Ag-g-P(HEMA)) as a matrix for the controlled release of 5-aminosalicylic acid was investigated. Grafted copolymers of 2-hydroxyethylmethacrylate (HEMA) monomers on agar were synthesized by microwave assisted method. drug release studies were performed at pH values of 2 and 7 in order to investigate the possibility of pH triggered release for colon targeted drug delivery. Further, the percent grafting . (the time taken for release of 50% of the enclosed drug) value was studied and the results indicate that it may be possible to develop a programmable drug release matrix based on grafted polysaccharide. Ag-g-P(HEMA) appears to be a useful matrix for controlled release.

关键词： agar     controlled drug release     5-Amino salicylic acid     poly(2-hydroxyethylmethacrylate) grafted agar    

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Preparation and swelling properties of a starch-g-poly(acrylic acid)/organo-mordenite hydrogel composite

Yan Zhang,Pingqiang Gao,Lin Zhao,Yizhong Chen

《化学科学与工程前沿（英文）》 2016年 第10卷 第1期   页码 147-161 doi: 10.1007/s11705-015-1546-y

摘要： A novel hydrogel composite was prepared via inverse suspension polymerization using starch, acrylic acid and organo-mordenite micropowder with the crosslinker, , ′-methylenebisacrylamide and the initiator, potassium persulfate. Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, scanning electron microscopy, and energy dispersive spectroscopy confirmed that the acrylic acid was grafted onto the backbone of the corn starch, that the organo-mordenite participated in the polymerization, and that the addition of organo-mordenite improved the surface morphology of the hydrogel composite. The swelling capacity of the hydrogel composite was evaluated in distilled water, and solutions with different pH values, and various salt solutions. It was found that the incorporation of 10 wt-% organo-mordenite enhanced the water absorbency by 144% (from 268 to 655 g·g ) and swelling was extremely sensitive to the pH values, the concentration of the salt solution and cation type. Swelling kinetics and water diffusion mechanism of the hydrogel composite in distilled water were also discussed. Moreover, the hydrogel composite showed excellent reversibility of water absorption even after five repetitive cycles and the hydrogel composite exhibited significant environmental-responsiveness by changing the swelling medium from distilled water to 0.1 mol·L NaCl solution. In addition, the loading and release of urea by the hydrogel composite were tested and the nutrient-slow-release capability of this material was found to be suitable for many potential applications.

关键词： hydrogel composite     environmental-responsiveness     organo-mordenite     starch     acrylic acid    

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Surface Polysaccharide Are Protective Against a Wide Range of Microbial Pathogens Producing β-1–6-Linked Poly-N-Acetylglucosamine

Xi Lu,Guoqing Li,Jing Pang,Xinyi Yang,Colette Cywes-Bentley,Xuefu You,Gerald B. Pier,

《工程（英文）》 doi: 10.1016/j.eng.2023.09.012

摘要： The β-1–6-linked poly-N-acetylglucosamine (PNAG) polymer is a conserved surface polysaccharide produced by many bacteria, fungi, and protozoan (and even filarial) parasites. This wide-ranging expression makes PNAG an attractive target for vaccine development, as it potentially encompasses a broad range of microorganisms. Significant progress has been made in discovering important properties of the biology of PNAG expression in recent years. The molecular characterization and regulation of operons for the production of PNAG biosynthetic proteins and enzymes have been studied in many bacteria. In addition, the physiological function of PNAG has been further elucidated. PNAG-based vaccines and PNAG-targeting antibodies have shown great efficacy in preclinical research. Furthermore, clinical tests for both vaccines and antibodies have been carried out in humans and economically important animals, and the results are promising. Although it is not destined to be a smooth road, we are optimistic about new vaccines and immunotherapeutics targeting PNAG becoming validated and eventually licensed for clinical use against multiple infectious agents.

关键词： Poly-     N     -acetylglucosamine     Conjugate vaccine     Monoclonal antibody    

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Kinetic analysis of anaerobic phosphorus release during biological phosphorus removal process

DOU Junfeng, LIU Xiang, LUO Guyuan

《环境科学与工程前沿（英文）》 2007年 第1卷 第2期   页码 233-239 doi: 10.1007/s11783-007-0040-2

摘要： Enhanced biological phosphorus removal (EBPR) is a commonly used and sustainable method for phosphorus removal from wastewater. Poly-β-hydroxybutyrate (PHB), polyphosphate, and glycogen are three kinds of intracellular storage polymers in phosphorus accumulation organisms. The variation of these polymers under different conditions has an apparent influence on anaerobic phosphorus release, which is very important for controlling the performance of EBPR. To obtain the mechanism and kinetic character of anaerobic phosphorus release, a series of batch experiments were performed using the excessively aerated sludge from the aerobic unit of the biological phosphorus removal system in this study. The results showed that the volatile suspended solid (VSS) had an increasing trend, while the mixed liquid suspended sludge (MLSS) and ashes were reduced during the anaerobic phosphorus release process. The interruption of anaerobic HAc-uptake and phosphorus-release occurs when the glycogen in the phosphorus-accumulating-organisms is exhausted. Under the condition of lower initial HAc-COD, HAc became the limiting factor after some time for anaerobic HAc uptake. Under the condition of higher initial HAc-COD, HAc uptake was stopped because of the depletion of glycogen in the microorganisms. The mean ratio of ΔρP/Δρ, Δρ/ΔρPHB, ΔρP/ΔCOD, and ΔρPHB/ΔCOD was 0.48, 0.50, 0.44, and 0.92, respectively, which was nearly the same as the theoretical value. The calibrated kinetic parameters of the HAc-uptake and phosphorus-release model were evaluated as follows: Q was 164 mg/(g °h), Q was 69.9 mg/(g °h), K was 0.005, and KCOD was 3 mg/L. An apparently linear correlation was observed between the ratio of ΔρP/ΔCOD and pH of the solution, and the equation between them was obtained in this study.

关键词： interruption     process     ΔρP/Δρ     Enhanced biological     Poly-β-hydroxybutyrate    

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Synthesis of poly(maleic acid alkylamide-

Jingjing XU, Jun XU, Jie SUN, Shili XING, Li LI, Xuhong GUO

《化学科学与工程前沿（英文）》 2011年 第5卷 第1期   页码 74-78 doi: 10.1007/s11705-010-0542-5

摘要： To improve the flow ability of crude oil with high content of aromatic asphaltenes, new comb-type copolymers of poly(maleic anhydride- - -olefin- -styrene) (MASCs) with different ratios of maleic anhydride (MA) to styrene were designed and synthesized. H NMR and FTIR spectra were used to characterize the chemical structure of the copolymers. The effect of copolymers on the flow ability of model waxy oil and crude oil were studied by rheological method and polarizing light microscopy. Upon the addition of MASCs, the yield stresses of oils were decreased by 1 to 3 orders of magnitude, and the morphology of paraffin crystals were reduced and changed from plates to needles.

关键词： comb-polymers     styrene     paraffin     crystallization     flow ability    

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Nanosilver anchored alginate/poly(acrylic acid/acrylamide) double-network hydrogel composites for efficient

《化学科学与工程前沿（英文）》 2023年 第17卷 第7期   页码 893-905 doi: 10.1007/s11705-022-2290-8

摘要： A novel alginate/poly(acrylic acid/acrylamide) double-network hydrogel composite with silver nanoparticles was successfully fabricated using the sol–gel method. The presence of carboxyl and amide groups in the network structure provided abundant active sites for complexing silver ions, facilitating the in situ reduction and confinement of silver nanoparticles. In batch experiments, the optimal silver loading was 20%, and 5 mmol·L–1 of p-nitrophenol was completely degraded in 113 s with a rate constant value of 4.057 × 10−2 s–1. In the tap water system and simulated seawater system, the degradation time of p-nitrophenol at the same concentration was 261 and 276 s, respectively, with a conversion rate above 99%. In the fixed-bed experiment, the conversion rate remained above 74% after 3 h at a flowing rate of 7 mL·min–1. After 8 cycling tests, the conversion rate remained at 98.7%. Moreover, the catalyst exhibited outstanding performance in the degradation experiment of four typical organic dyes.

关键词： double-network hydrogel     dye degradation     silver nanoparticles     alginate    

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Mutagenesis and selective breeding of a high producing

Tian WANG, Shiru JIA, Zhilei TAN, Yujie DAI, Shuai SONG, Guoliang WANG

《化学科学与工程前沿（英文）》 2012年 第6卷 第2期   页码 179-183 doi: 10.1007/s11705-012-1273-6

摘要： -Poly- -lysine ( -PL) is an -lysine linear homopolymer, which is produced by bacteria belonging to the family and by ergot fungi. However, the production of -PL by the wild bacteria strain is very low, which limits its utilization. In most bacteria including the genus, -lysine is a precursor of -PL and is biosynthesized by the -aspartate pathway. Aspartokinase (Ask) is the first key enzyme in this pathway and is subject to complex regulation such as the feedback inhibition by the end product amino acids. In addition, phosphoenolpyruvate carboxykinase is feedback-regulated by -aspartate. To reduce these feedback inhibitions and to improve -PL productivity, resistant mutants were produced using sulfaguanidine (SG) + glycine+ -lysine+ -3-hydroxynorvaline (AHV) as selective markers. Using the interaction between -PL and the charged dye in the solid culture medium, hundreds of colonies were simultaneously screened in a quick and effective manner. Finally, one -PL-producing strain, L9, was selected. The productivity of this strain during flask fermentation was 0.77 g/L, which was 15% higher than that of the original strain. Moreover, its fermentation performance and genetic characteristics were very stable.

关键词： ?-poly-L-lysine     plasma     AHV     Streptomyces diastatochromogenes     fermentation    

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Polymeric micelle nanocarriers in cancer research

Dae Hwan Shin, Yu Tong Tam, Glen S. Kwon

《化学科学与工程前沿（英文）》 2016年 第10卷 第3期   页码 348-359 doi: 10.1007/s11705-016-1582-2

摘要： Amphiphilic block copolymers (ABCs) assemble into a spherical nanoscopic supramolecular core/shell nanostructure termed a polymeric micelle that has been widely researched as an injectable nanocarrier for poorly water-soluble anticancer agents. The aim of this review article is to update progress in the field of drug delivery towards clinical trials, highlighting advances in polymeric micelles used for drug solubilization, reduced off-target toxicity and tumor targeting by the enhanced permeability and retention (EPR) effect. Polymeric micelles vary in stability in blood and drug release rate, and accordingly play different but key roles in drug delivery. For intravenous (IV) infusion, polymeric micelles that disassemble in blood and rapidly release poorly water-soluble anticancer agent such as paclitaxel have been used for drug solubilization, safety and the distinct possibility of toxicity reduction relative to existing solubilizing agents, e.g., Cremophor EL. Stable polymeric micelles are long-circulating in blood and reduce distribution to non-target tissue, lowering off-target toxicity. Further, they participate in the EPR effect in murine tumor models. In summary, polymeric micelles act as injectable nanocarriers for poorly water-soluble anticancer agents, achieving reduced toxicity and targeting tumors by the EPR effect.

关键词： nanomedicine     parenteral     poly(ethylene glycol)     poly(lactic acid)     reformulation    

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Deposition of copper nanoparticles on multiwalled carbon nanotubes modified with poly (acrylic acid)

Li SHENG,Shuhang HUANG,Minghao SUI,Lingdian ZHANG,Lei SHE,Yong CHEN

《环境科学与工程前沿（英文）》 2015年 第9卷 第4期   页码 625-633 doi: 10.1007/s11783-014-0711-8

摘要： A novel hybrid material, Cu-PAA/MWCNTs (copper nanoparticles deposited multiwalled carbon nanotubes with poly (acrylic acid) as dispersant, was prepared and expected to obtain a more effective and well-dispersed disinfection material for water treatment. X-ray energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), the X-ray fluorescence (XRF), X-ray photoelectron spectra (XPS), Fourier transform infrared spectra (FT-IR), Raman spectroscopy, and thermal gravimetric analyzer (TGA) were used to characterize the Cu-PAA/MWCNTs. ( ) was employed as the target bacteria. The cell viability determination and fluorescence imaging results demonstrated that Cu-PAA/MWCNTs possessed strong antimicrobial ability on . The deposited Cu was suggested to play an important role in the antimicrobial action of Cu-PAA/MWCNTs.

关键词： multiwalled carbon nanotubes     copper nanoparticles     antimicrobial activity     Escherichia coli (E. coil)    

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Ultrafast-laser-treated poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) electrodes with enhanced

《化学科学与工程前沿（英文）》 2023年 第17卷 第2期   页码 206-216 doi: 10.1007/s11705-022-2203-x

摘要： Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is an important organic electrode for solution-processed low-cost electronic devices. However, it requires doping and post-solvent treatment to improve its conductivity, and the chemicals used for such treatments may affect the device fabrication process. In this study, we developed a novel route for exploiting ultrafast lasers (femtosecond and picosecond laser) to simultaneously enhance the conductivity and transparency of PEDOT:PSS films and fabricate patterned solution-processed electrodes for electronic devices. The conductivity of the PEDOT:PSS film was improved by three orders of magnitude (from 3.1 to 1024 S·cm–1), and high transparency of up to 88.5% (average visible transmittance, AVT) was achieved. Raman and depth-profiling X-ray photoelectron spectroscopy revealed that the oxidation level of PEDOT was enhanced, thereby increasing the carrier concentration. The surface PSS content also decreased, which is beneficial to the carrier mobility, resulting in significantly enhanced electrical conductivity. Further, we fabricated semitransparent perovskite solar cells using the as-made PEDOT:PSS as the transparent top electrodes, and a power conversion efficiency of 7.39% was achieved with 22.63% AVT. Thus, the proposed route for synthesizing conductive and transparent electrodes is promising for vacuum and doping-free electronics.

关键词： PEDOT:PSS     ultrafast laser     transparent electrode     ST-PSCs     patterning    

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Hydrophilic modification of poly(aryl sulfone) membrane materials toward highly-efficient environmental

《化学科学与工程前沿（英文）》 2022年 第16卷 第5期   页码 614-633 doi: 10.1007/s11705-021-2115-1

摘要： Poly(aryl sulfone) as a typical membrane material has been widely used due to excellent mechanical, chemical and thermal stability. However, the inherent hydrophobicity of poly(aryl sulfone) based membranes bears with the fouling issue during applications, which makes the membrane tending to adsorb contaminants on the surface so as to result in decreased separation performance and lifetime. In this critical review, we give a comprehensive overview on characterizations of hydrophilic membrane and diverse hydrophilic modification approaches of poly(aryl sulfone) membranes, predominantly including bulky, blending and surface modification technology. The discussions on the different modification methods have been provided in-depth. Besides, focusing on modification methods and performance of modified membranes, the related mechanisms for the performance enhancement are discussed too. At last, the perspectives are provided to guide the future directions to develop novel technology to manipulate the hydrophilicity of poly(aryl sulfone) membranes toward diverse practical and multi-functional applications.

关键词： poly(aryl sulfone)     membrane separations     modification     hydrophilicity     water treatment    

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生物基全降解复合材料

刘小刚,王莉,李十中,樊琛语

《中国工程科学》 2011年 第13卷 第2期   页码 90-95

摘要：

淀粉/聚乳酸复合具有相对较好的力学性能和生物降解性能，价格也与石油基塑料最为接近，是极具应用前景的全生物降解塑性材料。在分析国内外聚乳酸、淀粉及其复合材料研究现状的基础上，对该类材料的技术发展方向和工业化前景进行了展望。

关键词： 研究进展     生物基材料     降解     淀粉     聚乳酸    

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Preparation and characterization of poly (vinylidene fluoride)/TiO

Weiying LI, Xiuli SUN, Chen WEN, Hui LU, Zhiwei WANG

《环境科学与工程前沿（英文）》 2013年 第7卷 第4期   页码 492-502 doi: 10.1007/s11783-012-0407-x

摘要： Poly(vinylidene fluoride) (PVDF)/titanium dioxide (TiO ) hybrid membranes were prepared using nano-TiO as the modifier, and characterized by Transmission Electron Microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), atomic force microscope (AFM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The characterization results demonstrated that nano-sized TiO particles dispersed homogeneously within the PVDF matrix, contributing to more hydroxyls and smoother surfaces. Moreover, permeate flux, retention factor, porosity, contact angle and anti-fouling tests were carried out to evaluate the effect of TiO concentration on the performance of PVDF membranes. Among all the prepared membranes, PVDF/TiO membrane containing 10 vol.% TiO exhibited the best hydrophilicity with an average pure water flux up to 237 L·m ·h , higher than that of unmodified PVDF membranes (155 L·m ·h ). Besides, the bovine serum albumin rejection of the hybrid membrane was improved evidently from 52.3% to 70.6%, and the contact angle was significantly lowered from 83° to 60°, while the average pore size and its distribution became smaller and narrower.

关键词： poly(vinylidene fluoride) (PVDF) membrane     nano-TiO2     anti-fouling performance     water treatment    

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标题 作者 时间 类型 操作

Genomic and metabolomic analysis of with enhanced poly--glutamic acid production through atmospheric

期刊论文

Effect of polyethylene glycol on the crystallization, rheology and foamability of poly(lactic acid) containing

期刊论文

Controlled drug release of 5-amino salicylic acid by poly(2-hydroxyethylmethacrylate) grafted agar

G. Usha RANI,Kartick Prasad DEY,Srijita BHARTI,Sumit MISHRA

期刊论文

Preparation and swelling properties of a starch-g-poly(acrylic acid)/organo-mordenite hydrogel composite

Yan Zhang,Pingqiang Gao,Lin Zhao,Yizhong Chen

期刊论文

Surface Polysaccharide Are Protective Against a Wide Range of Microbial Pathogens Producing β-1–6-Linked Poly-N-Acetylglucosamine

Xi Lu,Guoqing Li,Jing Pang,Xinyi Yang,Colette Cywes-Bentley,Xuefu You,Gerald B. Pier,

期刊论文

Kinetic analysis of anaerobic phosphorus release during biological phosphorus removal process

DOU Junfeng, LIU Xiang, LUO Guyuan

期刊论文

Synthesis of poly(maleic acid alkylamide-

Jingjing XU, Jun XU, Jie SUN, Shili XING, Li LI, Xuhong GUO

期刊论文

Nanosilver anchored alginate/poly(acrylic acid/acrylamide) double-network hydrogel composites for efficient

期刊论文

Mutagenesis and selective breeding of a high producing

Tian WANG, Shiru JIA, Zhilei TAN, Yujie DAI, Shuai SONG, Guoliang WANG

期刊论文

Polymeric micelle nanocarriers in cancer research

Dae Hwan Shin, Yu Tong Tam, Glen S. Kwon

期刊论文

Deposition of copper nanoparticles on multiwalled carbon nanotubes modified with poly (acrylic acid)

Li SHENG,Shuhang HUANG,Minghao SUI,Lingdian ZHANG,Lei SHE,Yong CHEN

期刊论文

Ultrafast-laser-treated poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) electrodes with enhanced

期刊论文

Hydrophilic modification of poly(aryl sulfone) membrane materials toward highly-efficient environmental

期刊论文

生物基全降解复合材料

刘小刚,王莉,李十中,樊琛语

期刊论文

Preparation and characterization of poly (vinylidene fluoride)/TiO

Weiying LI, Xiuli SUN, Chen WEN, Hui LU, Zhiwei WANG

期刊论文