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Use of dry yeast cells as a cheap nitrogen source for lactic acid production by thermophilic

Kim Yng Ooi, Jin Chuan Wu

《化学科学与工程前沿（英文）》 2015年 第9卷 第3期   页码 381-385 doi: 10.1007/s11705-015-1534-2

摘要： Dry yeast cells (DYC) were used as a cheap nitrogen source to replace expensive yeast extract (YE) for L-lactic acid production by thermophilic . Cassava starch (200 g·L ) was converted to L-lactic acid by simultaneous saccharification and fermentation using WCP10-4 at 50 °C in the presence of 20 g·L of DYC, giving 148.1 g·L of L-lactic acid at 27 h with a productivity of 5.5 g·L ·h and a yield of 92%. In contrast, 154.4 g·L of lactic acid was produced at 24 h with a productivity of 6.4 g·L ·h and a yield of 96% when equal amount of YE was used under the same conditions. Use of pre-autolyzed DYC at 50 °C for overnight slightly improved the lactic acid titer (154.5 g·L ) and productivity (7.7 g·L ·h ) but gave the same yield (96%).

关键词： L-lactic acid     thermophilic strain     Bacillus coagulans     dry yeast cells     autolysis     fermentation    

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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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Invading target cells: multifunctional polymer conjugates as therapeutic nucleic acid carriers

Ulrich L?CHELT, Ernst WAGNER

《化学科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 275-286 doi: 10.1007/s11705-011-1203-z

摘要： Polymer-based conjugates are an interesting option and challenge for the design of nano-sized drug-delivery systems, as they require advanced conjugation chemistry and precise engineering. In the case of nucleic acid therapy, non-viral carriers face several biological barriers during the delivery process, namely 1) protection of the cargo from extracellular degradation, 2) avoidance of non-specific interactions with non-targeted tissues, 3) efficient entry into the target cells, 4) intracellular trafficking to the site of action and 5) cargo release. To take on these obstacles, multifunctional conjugates can act as “smart polymers” with microenvironment-sensing dynamics to facilitate the separate delivery steps. Synthesis of defined polymer architectures with precise functionalization enables structure-activity relationships to be investigated and the integration of key functions for efficient delivery. Thus bioresponsive polymer conjugates, which are equipped with molecular devices responding to the certain microenvironments within the delivery pathway (e.g. pH, redox potential, enzymes) can be assembled. This review focuses on the modular engineering and conjugation of multifunctional polymeric structures for the utilization as “tailor-made” nucleic acid carriers.

关键词： conjugate     DNA     gene transfer     polymer     RNA     targeting    

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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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Diphenylarsinic acid sorption mechanisms in soils using batch experiments and EXAFS spectroscopy

Zhu, Yongming Luo, Ruyi Yang, Shoubiao Zhou, Juqin Zhang, Mengyun Zhang, Peter Christie, Elizabeth L.

《环境科学与工程前沿（英文）》 2020年 第14卷 第4期 doi: 10.1007/s11783-020-1237-x

摘要： DPAA sorption data was found to fit the Freundlich equation. Kf was significantly positive correlated with oxalate-extractable Fe2O3. Ligand exchange was the main mechanism for DPAA sorption on soils. Bidentate binuclear and monodentate mononuclear DPAA bonds were identified. Diphenylarsinic acid (DPAA) is a phenyl arsenic compound derived from chemical warfare weapons. Macroscopic and microscopic work on DPAA sorption will provide useful information in predicting the partitioning and mobility of DPAA in the soil-water environment. Here, batch experiments and extended X-ray absorption fine structure (EXAFS) spectroscopy were used to investigate the sorption mechanisms of DPAA. The DPAA sorption data from 11 soil types was found to fit the Freundlich equation, and the sorption capacity, Kf, was significantly and positively correlated with oxalate-extractable Fe2O3. The Kf values of eight of the 11 untreated soils (1.51–113.04) significantly decreased upon removal of amorphous metal (hydr)oxides (0.51–13.37). When both amorphous and crystalline metal (hydr)oxides were removed from the untreated soils, the Kf values either decreased or slightly increased (0.65–3.09). Subsequent removal of soil organic matter from these amorphous and crystalline metal (hydr)oxide-depleted samples led to further decreases in Kf to 0.02–1.38, with only one exception (Sulfic Aquic-Orthic Halosols). These findings strongly suggest that ligand exchange reactions with amorphous metal (hydr)oxides contribute most to DPAA sorption on soils. EXAFS data provide further evidence that DPAA primarily formed bidentate binuclear (2C) and monodentate mononuclear (1V) coring-sharing complexes with As-Fe distances of 3.34 and 3.66 Å, respectively, on Fe (hydr)oxides. Comparison of these results with earlier studies suggests that 2C and 1V complexes of DPAA may be favored under low and high surface coverages, respectively, with the formation of 1V bonds possibly conserving the sorption sites or decreasing the steric hindrance derived from phenyl substituents.

关键词： Diphenylarsinic acid     EXAFS     Fe (hydr)oxide     Soil organic matter     Sorption mechanism    

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Enhanced Fenton-like process over Cu/L(+)-ascorbic acid co-doping mesoporous silica for toxicity reduction

《环境科学与工程前沿（英文）》 2023年 第18卷 第4期 doi: 10.1007/s11783-024-1804-7

摘要：

● Cu-C-MSNs are developed via a co-doping step of Cu with L(+)-ascorbic acid.

关键词： Cation-π structures     Polarization electric field     Fenton-like process     Contaminants cleavage    

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增强生物工程化的前交叉韧带基质的表面特性用于即时干细胞治疗 Article

Xiaohua Yu, Paulos Y. Mengsteab, Ganesh Narayanan, Lakshmi S. Nair, Cato T. Laurencin

《工程（英文）》 2021年 第7卷 第2期   页码 153-161 doi: 10.1016/j.eng.2020.02.010

摘要：

我们之前已经研发了一种生物工程化的左旋聚乳酸（PLLA）前交叉韧带（ACL）基质，该基质在植入兔模型之前被接种了原代ACL细胞，表现出比基质单独作用时更强的愈合能力。这表明改善细胞在基质上的黏附性可能有益于生物工程化的ACL基质的愈合反应和长期性能。一种与即时诊疗干细胞疗法相结合的再生工程方法是，增强基质的表面特性来支持细胞黏附和生长。在本文中，我们研究了通过纤连蛋白的物理吸附和空气等离子体处理来增强PLLA编织超细纤维基质的细胞黏附性能。我们在三个时间点和三个纤连蛋白浓度下评估了纤连蛋白在基质上的动力学和结合效率。在25 μg·mL–1纤连蛋白溶液中孵育120 min，可实现基质的最大结合效率和细胞黏附性。在纤连蛋白吸附之前将基质置于空气等离子体中处理5 min，可显著增强接种24 h后兔骨髓间充质干细胞（R-BMMSC）的黏附性。最后，监测细胞增殖长达21 d，将基质用空气等离子体处理后，发现纤连蛋白的吸附性导致细胞数量增加。这些发现表明，空气等离子体处理和纤连蛋白吸附可以增强PLLA编织超细纤维基质的细胞黏附性，可改善基质在即时诊疗干细胞疗法中的临床疗效。

关键词： 前交叉韧带     韧带     左旋聚乳酸等离子体处理     纤连蛋白     干细胞     黏附性    

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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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Nucleic acid-based diagnostics for infectious diseases in public health affairs

null

《医学前沿（英文）》 2012年 第6卷 第2期   页码 173-186 doi: 10.1007/s11684-012-0195-5

摘要：

Infectious diseases, mostly caused by bacteria and viruses but also a result of fungal and parasitic infection, have been one of the most important public health concerns throughout human history. The first step in combating these pathogens is to get a timely and accurate diagnosis at an affordable cost. Many kinds of diagnostics have been developed, such as pathogen culture, biochemical tests and serological tests, to help detect and fight against the causative agents of diseases. However, these diagnostic tests are generally unsatisfactory because they are not particularly sensitive and specific and are unable to deliver speedy results. Nucleic acid-based diagnostics, detecting pathogens through the identification of their genomic sequences, have shown promise to overcome the above limitations and become more widely adopted in clinical tests. Here we review some of the most popular nucleic acid-based diagnostics and focus on their adaptability and applicability to routine clinical usage. We also compare and contrast the characteristics of different types of nucleic acid-based diagnostics.

关键词： nucleic acid-based diagnostics     infectious disease     PCR     NASBA     LAMP     microarray     LOAC     public health affairs    

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degradation of trichloroethene by calcium peroxide activated with Fe(III) in the presence of citric acid

Xiang ZHANG,Xiaogang GU,Shuguang LU,Zhouwei MIAO,Minhui XU,Xiaori FU,Muhammad DANISH,Mark L.

《环境科学与工程前沿（英文）》 2016年 第10卷 第3期   页码 502-512 doi: 10.1007/s11783-016-0838-x

摘要： Trichloroethene (TCE) degradation by Fe(III)-activated calcium peroxide (CP) in the presence of citric acid (CA) in aqueous solution was investigated. The results demonstrated that the presence of CA enhanced TCE degradation significantly by increasing the concentration of soluble Fe(III) and promoting H O generation. The generation of HO? and O ? in both the CP/Fe(III) and CP/Fe(III)/CA systems was confirmed with chemical probes. The results of radical scavenging tests showed that TCE degradation was due predominantly to direct oxidation by HO?, while O ? strengthened the generation of HO? by promoting Fe(III) transformation in the CP/Fe(III)/CA system. Acidic pH conditions were favorable for TCE degradation, and the TCE degradation rate decreased with increasing pH. The presence of Cl , HCO , and humic acid (HA) inhibited TCE degradation to different extents for the CP/Fe(III)/CA system. Analysis of Cl production suggested that TCE degradation in the CP/Fe(III)/CA system occurred through a dechlorination process. In summary, this study provided detailed information for the application of CA-enhanced Fe(III)-activated calcium peroxide for treating TCE contaminated groundwater.

关键词： calcium peroxide     trichloroethene (TCE)     citric acid     ferric ion     free radicals     oxidation    

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Sulfonic acid-functionalized mesoporous silica catalyst with different morphology for biodiesel production

《化学科学与工程前沿（英文）》 2022年 第16卷 第8期   页码 1198-1210 doi: 10.1007/s11705-021-2133-z

摘要： Sulfonic acid functionalized mesoporous silica based solid acid catalysts with different morphology were designed and fabricated. The synthesized materials were characterized by various physicochemical and spectroscopic techniques like scanning electron microscope-energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller surface area, thermogravimetric analysis and n-butylamine acidity. The shape of catalysts particles plays an important role in its activity. The sulfonic acid functionalized mesoporous silica catalysts of spherical shape and the cube shape were assessed for catalytic activity in biodiesel production. The catalytic biodiesel production reaction over the catalysts were studied by esterification of free fatty acid, oleic acid with methanol. The effect of various reaction parameters such as catalyst concentration, acid/alcohol molar ratio, catalyst amount, reaction temperature and reaction time on catalytic activity were investigated to optimize the conditions for maximum conversion. It was sulfonated cubic shape mesoporous silica which exhibited better activity as compared to the spherical shape silica catalysts. Additionally, the catalyst was regenerated and reused up to three cycles without any significant loss in activity. The present catalysts exhibit superior performance in biodiesel production and it can be used for the several biodiesel feedstock’s that are rich in free fatty acids.

关键词： solid acid catalyst     mesoporous silica     sulfonic acid     biodiesel     esterification     oleic acid    

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Comments on the special issue on forestry of

John L. INNES

《农业科学与工程前沿（英文）》 2017年 第4卷 第4期   页码 502-503 doi: 10.15302/J-FASE-2017189

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Amino acid promoted hydrogen battery system using Mn-pincer complex for reversible CO hydrogenation toformic acid

《能源前沿（英文）》 2022年 第16卷 第5期   页码 697-699 doi: 10.1007/s11708-022-0843-7

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Enzyme@bismuth-ellagic acid: a versatile platform for enzyme immobilization with enhanced acid-base stability

《化学科学与工程前沿（英文）》 2023年 第17卷 第6期   页码 784-794 doi: 10.1007/s11705-022-2278-4

摘要： In situ encapsulation is an effective way to synthesize enzyme@metal–organic framework biocatalysts; however, it is limited by the conditions of metal–organic framework synthesis and its acid-base stability. Herein, a biocatalytic platform with improved acid-base stability was constructed via a one-pot method using bismuth-ellagic acid as the carrier. Bismuth-ellagic acid is a green phenol-based metal–organic framework whose organic precursor is extracted from natural plants. After encapsulation, the stability, especially the acid-base stability, of amyloglucosidases@bismuth-ellagic acid was enhanced, which remained stable over a wide pH range (2–12) and achieved multiple recycling. By selecting a suitable buffer, bismuth-ellagic acid can encapsulate different types of enzymes and enable interactions between the encapsulated enzymes and cofactors, as well as between multiple enzymes. The green precursor, simple and convenient preparation process provided a versatile strategy for enzymes encapsulation.

关键词： bismuth-ellagic acid     in situ encapsulation     enzyme@MOF biocomposites    

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Discovery of novel ursolic acid derivatives as effective antimicrobial agents through a ROS-mediated

《化学科学与工程前沿（英文）》 2023年 第17卷 第12期   页码 2101-2113 doi: 10.1007/s11705-023-2361-5

摘要： In response to the reduction of food production and economic losses caused by plant bacterial diseases, it is necessary to develop new, efficient, and green pesticides. Natural products are rich and sustainable source for the development of new pesticides due to their low toxicity, easy degradation, and eco-friendliness. In this study, we prepared three series of ursolic acid derivatives and assessed their antibacterial ability. Most target compounds exhibited outstanding antibacterial activities. Among them, the relative optimal EC50 values of Xanthomonas oryzae pv. oryzae and Xanthomonas axonopodis pv. citri were 2.23 (A17) and 1.39 (A16) μg·mL–1, respectively. The antimicrobial mechanism showed that compound A17 induced an excessive accumulation and production of reactive oxygen species in bacteria and damaged the cell membrane integrity to kill bacteria. More interestingly, the addition of low concentrations of exogenous hydrogen peroxide enhanced the antibacterial efficacy of compound A17 against Xanthomonas oryzae pv. oryzae. These entertaining results suggested that compound A17 induced an apparent apoptotic behavior in the tested bacteria. Overall, we developed the promising antimicrobial agents that destroyed the redox system of phytopathogenic bacteria, further demonstrating the unprecedented potential of ursolic acid for agricultural applications.

关键词： ursolic acid     antibacterial activities     reactive oxygen species     apoptosis    

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标题 作者 时间 类型 操作

Use of dry yeast cells as a cheap nitrogen source for lactic acid production by thermophilic

Kim Yng Ooi, Jin Chuan Wu

期刊论文

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

期刊论文

Invading target cells: multifunctional polymer conjugates as therapeutic nucleic acid carriers

Ulrich L?CHELT, Ernst WAGNER

期刊论文

Polymeric micelle nanocarriers in cancer research

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

期刊论文

Diphenylarsinic acid sorption mechanisms in soils using batch experiments and EXAFS spectroscopy

Zhu, Yongming Luo, Ruyi Yang, Shoubiao Zhou, Juqin Zhang, Mengyun Zhang, Peter Christie, Elizabeth L.

期刊论文

Enhanced Fenton-like process over Cu/L(+)-ascorbic acid co-doping mesoporous silica for toxicity reduction

期刊论文

增强生物工程化的前交叉韧带基质的表面特性用于即时干细胞治疗

Xiaohua Yu, Paulos Y. Mengsteab, Ganesh Narayanan, Lakshmi S. Nair, Cato T. Laurencin

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

Nucleic acid-based diagnostics for infectious diseases in public health affairs

null

期刊论文

degradation of trichloroethene by calcium peroxide activated with Fe(III) in the presence of citric acid

Xiang ZHANG,Xiaogang GU,Shuguang LU,Zhouwei MIAO,Minhui XU,Xiaori FU,Muhammad DANISH,Mark L.

期刊论文

Sulfonic acid-functionalized mesoporous silica catalyst with different morphology for biodiesel production

期刊论文

Comments on the special issue on forestry of

John L. INNES

期刊论文

Amino acid promoted hydrogen battery system using Mn-pincer complex for reversible CO hydrogenation toformic acid

期刊论文

Enzyme@bismuth-ellagic acid: a versatile platform for enzyme immobilization with enhanced acid-base stability

期刊论文

Discovery of novel ursolic acid derivatives as effective antimicrobial agents through a ROS-mediated

期刊论文