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c/N Ratio and Specific Growth Rate Plays Important Role on Enhancing Isoprene Production in Recombinant Escherichia coli

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APPLIED BIOcHEMISTRY AND BIOTEcHNOLOGY 2021年第8期193卷 2403-2419页

作者： Joshi, Harshvardhan Isar, Jasmine Jain, Dharmendra A. Badle, Sneh S. Dhoot, Shrikant B. Rangaswamy, Vidhya Reliance Ind Ltd High Value Chem Navi Mumbai 400701 Maharashtra India

Effect of fermentation parameters such as c/N ratio, specific growth rate, phosphate limitation, and plasmid instability on enhancing isoprene production is the focus of the current study. Isoprene productivity in the recombinant Escherichia coli K12_MVA strain showed a bell-shaped relationship with specific growth rate in bioreactor studies with isoprene volumetric productivity peaking at 0.35/h. This behavior was depicted by a production inhibition kinetic model which envisaged a serious competition between the cellular growth, acetic acid production, and isoprene biosynthesis. The model equation derived showed a reasonable fit with the experimental values. Judicious control of the growth rates and acetate accumulation by optimizing c/N ratio, phosphate concentration, and intermittent feeding strategy resulted in maximizing the carbon flux towards isoprene. Plasmid instability caused by metabolic burden posed by the presence of dual plasmids on the bacteria was simulated using first-order degradation kinetics. The experimental plasmid loss trend was in accordance with the model simulated trend, where higher plasmid loss correlated with higher specific growth rates. Modulating the growth rate, acetate accumulation, and plasmid instability resulted in achieving maximum isoprene volumetric productivity of 1.125 g/l/h with 46.67% of carbon flux towards isoprene and a isoprene titre of 18 g/l in 16 h fermentation run.

关键词： Isoprene fermentation Plasmid instability c N ratio Acetate toxicity

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Benchmarking Java against c and Fortran for scientific applications

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cONcURRENcY AND cOMPUTATION-PRAcTIcE & EXPERIENcE 2003年第3-5期15卷 417-430页

作者： Bull, JM Smith, LA Ball, c Pottage, L Freeman, R Univ Edinburgh Edinburgh Parallel Comp Ctr Edinburgh EH9 3JZ Midlothian Scotland

Increasing interest is being shown in the use of Java for scientific applications. The Java Grande benchmark suite was designed with such applications primarily in mind. The perceived lack of performance of Java still deters many potential users, despite recent advances in just-in-time and adaptive compilers. There are, however, few benchmark results available comparing Java to more traditional languages such as c and Fortran. To address this issue, a subset of the Java Grande benchmarks has been re-written in c and Fortran allowing direct performance comparisons between the three languages. The performance of a range of Java execution environments, c and Fortran compilers have been tested across a number of platforms using the suite. These demonstrate that on some platforms (notable Intel Pentium) the performance gap is now quite small. copyright (c) 2003 John Wiley Sons, Ltd.

关键词： Java c Fortran performance benchmarking scientific applications

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SafeOSL: Ensuring memory safety of c via ownership-based intermediate language

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SOFTWARE-PRAcTIcE & EXPERIENcE 2022年第5期52卷 1114-1142页

作者： Yin, Xiaohua Huang, Zhiqiu Kan, Shuanglong Shen, Guohua chen, Zhe Liu, Yang Wang, Fei Nanjing Univ Aeronaut & Astronaut Coll Comp Sci & Technol Nanjing 211106 Peoples R China Collaborat Innovat Ctr Novel Software Technol & I Nanjing Peoples R China Minist Ind & Informat Technol Key Lab Safety Crit Software Nanjing Peoples R China TU Kaiserslautern Dept Comp Sci Kaiserslautern Germany Nanyang Technol Univ Sch Comp Sci & Engn Singapore Singapore Suzhou Univ Sci & Technol Sch Elect & Informat Engn Suzhou Peoples R China

The unsafe features of c make it a big challenge to ensure memory safety of c programs, and often lead to memory errors that can result in vulnerabilities. Various formal verification techniques for ensuring memory safety of c have been proposed. However, most of them either have a high overhead, such as state explosion problem in model checking, or have false positives, such as abstract interpretation. In this article, by innovatively borrowing ownership system from Rust, we propose a novel and sound static memory safety analysis approach, named SafeOSL. Its basic idea is an ownership-based intermediate language, called ownership system language (OSL), which captures the features of the ownership system in Rust. Ownership system specifies the relations among variables and memory locations, and maintains invariants that can ensure memory safety. The semantics of OSL is formalized in K-framework, which is a rewriting-logic based tool. c programs to be checked are first transformed into OSL programs and then detected by OSL semantics. Experimental results have demonstrated that SafeOSL is effective in detecting memory errors of c. Moreover, the translations and experiments indicate that the intermediate language OSL could be reused by other programming languages to detect memory errors.

关键词： c memory errors memory safety ownership system Rust

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Fecl3/c as an efficient catalyst for Ferrier rearrangement of 3,4,6-tri-O-Benzyl-D-glucal

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JOURNAL OF cARBOHYDRATE cHEMISTRY 2020年第5-6期39卷 232-249页

作者： Mei, Yuling Dong, Youxian Li, Juan Zhang, Bo Sun, Guosheng Zhou, Jiafen Si, Wenshuai Han, Yiwen Wu, Zhenliang Zhang, Jianbo East China Normal Univ Sch Chem & Mol Engn 500 Dongchuan Rd Shanghai 200241 Peoples R China

Fecl3/c was used as an efficient and convenient promoter for glycosylation through Ferrier-type rearrangement of 3,4,6-tri-O-benzyl-D-glucal, which is a relatively unreactive substrate for this type of reaction. The method was applicable to a wide range of alcohols, especially phenols. A series of 2,3-unsaturated-O-glucosides were prepared efficiently (47-92%) by this method under mild conditions.

关键词： Fecl3 c Ferrier rearrangement promoter glycosylation 346-tri-O-benzyl-D-glucal

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Effect of c/N ration on disposal of pig carcass by co-composting with swine manure: experiment at laboratory scale

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ENVIRONMENTAL TEcHNOLOGY 2021年第28期42卷 4415-4425页

作者： chen, Yan Li, Xiaoyu Li, Shuying Xu, Yongping Dalian Univ Technol Sch Bioengn Dalian 116024 Liaoning Peoples R China Minist Educ Ctr Food Safety Anim Origin Dalian 116620 Peoples R China Dalian SEM Bioengn Technol Co Ltd Dalian 116620 Peoples R China

Disposal of animal carcasses by co-composting with animal waste usually selected conventional carbon to nitrogen (c/N) ratio around 25:1, in which the compost is widely used throughout the world. In this study, the pig carcass tissue blocks were sampled for composting at a laboratory scale to evaluate the effect of c/N ratio on the pig carcass compost. The time of thermophilic phase between 60 degrees c - 70 degrees c at a lower c/N ratio of 20:1 was significantly longer than that at the conventional c/N ratio, and it was the only one with the temperature beyond 70 degrees c that lasted for 2 days. Germination index and T value (the final c/N ratio / the initial c/N ratio) of the treatment with a c/N ratio of 20:1 were 94.67% and 0.69, respectively, meeting the standards of animal carcass compost. The degradation rate was 75.67%, and no significant difference was obtained as compared to the conventional c/N ratio groups. Organic fertilizer produced from the treatment with a c/N ratio of 20:1 was selected to evaluate the fertility by pot experiment of cayenne pepper compared with chemical fertilizer. The results showed that organic fertilizer from this treatment could significantly improve the growth of cayenne pepper. Overall, the use of the lower c/N ratio of 20:1 in the disposal of pig carcass by co-composting with swine manure could achieve the similar degradation rate as well as the maturity and stability of organic fertilizer as compared with the traditional c/N ratio at lab scale.

关键词： Disposal of pig carcass co-composting c N ratio degradation rate organic fertilizer

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Realization of nitrite accumulation in an autotrophic-heterotrophic denitrification system using different S/N/c ratios coupled with ANAMMOX to achieve nitrogen removal

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JOURNAL OF cHEMIcAL TEcHNOLOGY AND BIOTEcHNOLOGY 2023年第1期98卷 269-281页

作者： Ma, Jiao Liu, Hong Dang, Hongzhong Wu, Xinbo Yan, Yuan Zeng, Tianxu Li, Weiwei chen, Yongzhi Lanzhou Jiaotong Univ Sch Environm & Municipal Engn Lanzhou 730070 Peoples R China Tech Ctr Sewage Treatment Ind Gansu Lanzhou Peoples R China Key Lab Yellow River Water Environm Gansu Prov Lanzhou Peoples R China

BAcKGROUND Nitrogen and sulfur pollutants have become an urgent problem in surface and groundwater. Short-cut denitrification coupled with anaerobic ammonia oxidation (ANAMMOX) is an economical and efficient biological nitrogen removal process. However, single heterotrophic denitrification and autotrophic denitrification face the problems of high treatment cost and high secondary sulfate pollution, respectively. Moreover, in real environments, single nutrient conditions are less common. Therefore, this work aims to study the process of mixotrophic short-cut denitrification coupled with ANAMMOX to achieve simultaneous nitrogen and sulfur removal. RESULTS Mixotrophic short-cut denitrification was successfully initiated on day 20, while the nitrite accumulation rate (NAR) was 81.47%. The optimal performance of the mixotrophic denitrification system was achieved when the ratio of sulfur to nitrogen to carbon (S/N/c) was 3/4/9, with S2--S, NO3--N, and cOD removal reaching 100%, 94.48%, and 95.48%, respectively, with a NAR of 94.24% and only 11.73 mg L-1 of SO42--S production. Modified Boltzmann and Gompertz models were found to be suitable to describe the removal of NO3--N, with both models exhibiting good data fitting (R-2 > 0.99). In addition, no distinctly dominant genus was found in the mixotrophic denitrification systems. Autotrophic, heterotrophic, and facultative denitrifying bacteria (such as Thiobacillus Pseudomonas and Halomonas) were found to coexist and synergistically perform denitrification. cONcLUSION Mixotrophic short-cut denitrification can achieve the efficient accumulation of NO2--N and reduce the amount of SO42--S production at the same time. Mixotrophic short-cut denitrification coupled with ANAMMOX can deeply remove sulfide, nitrogen, and organic carbon. (c) 2022 Society of chemical Industry.

关键词： S N c nitrite kinetics mixotrophic microbial community

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SELEcTIVE HYDROGENATION OF 3,4-DIMETHOXYBENZOPHENONE IN LIQUID PHASE OVER PD/c cATALYST IN A SLURRY REAcTOR

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cANADIAN JOURNAL OF cHEMIcAL ENGINEERING 2014年第12期92卷 2157-2165页

作者： Tiwari, Manishkumar S. Yadav, Ganapati D. Ng, Flora T. T. Inst Chem Technol Dept Chem Engn Mumbai 400019 Maharashtra India Univ Waterloo Dept Chem Engn Waterloo ON N2L 3G1 Canada

Selective hydrogenation of benzophenone to benzhydrol is industrially relevant. In the current work, selective hydrogenation of 3,4-dimethoxybenzophenone (3,4-DMBP) to 3,4-dimethoxybenzhydrol (3,4-DMBH) was investigated over 5% w/w Pd/c and 5% w/w Pt/c as catalysts in a slurry reactor. The effects of hydrogen partial pressure (0.2-1MPa), catalyst loading (2.0x10(-4) to 8.0x10(-4)g/cm(3)), initial concentration of 3,4-dimethoxybenzophenone (5.0x10(-6) to 1.5x10(-4)mol/cm(3)) and temperature (40-70 degrees c) on rate of reaction and selectivity were studied. Effect of solvent such as methanol, ethanol, 2-propanol and tetrahydrofuran (THF) was also investigated. 5% w/w Pd/c was the better catalyst with THF as the best solvent, which gave 100 % conversion and 80 % selectivity in 1h for 0.5MPa hydrogen pressure at 60 degrees c. The Langmuir-Hinshelwood-Hougen-Watson model was fitted. The intrinsic kinetics and mechanism of hydrogenation were established.

关键词： catalytic hydrogenation 3 4-Dimethoxybenzopheone Pd c 3 4-Dimethoxybenzhydrol kinetics

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Up-regulation of glycolipid transfer protein by bicyclol causes spontaneous restriction of hepatitis c virus replication

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Acta Pharmaceutica Sinica B 2019年第4期9卷 769-781页

作者： Meng-Hao Huang Hu Li Rong Xue Jianrui Li Lihua Wang Junjun cheng Zhouyi Wu Wenjing Li Jinhua chen Xiaoqin Lv Qiang Li Pei Lan Limin Zhao Yongfeng Yang Zonggen Peng Jiandong Jiang Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100050China Department of Liver Diseases the Second Hospital of NanjingSoutheast UniversityNanjing 210003China State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100050China

Bicyclol is a synthetic drug for hepatoprotection in clinic since 2004. Preliminary clinical observations suggest that bicyclol might be active against hepatitis c virus(HcV) with unknown mechanism. Here, we showed that bicyclol significantly inhibited HcV replication in vitro and in hepatitis c patients. Using bicyclol as a probe, we identified glycolipid transfer protein(GLTP) to be a novel restrictive factor for HcV replication. The GLTP preferentially bound host vesicle-associated membrane protein-associated protein-A(VAP-A) in competition with the HcV NS5 A, causing an interruption of the complex formation between VAP-A and HcV NS5 A. As the formation of VAP-A/NS5 A complex is essential for viral RNA replication, up-regulation of GLTP by bicyclol reduced the level of VAP-A/NS5 A complex and thus inhibited HcV replication. Bicyclol also exhibited an inhibition on HcV variants resistant to direct-acting antiviral agents(DAAs) with an efficacy identical to that on wild type HcV. In combination with bicyclol, DAAs inhibited HcV replication in a synergistic fashion. GLTP appears to be a newly discovered host restrictive factor for HcV replication, Up-regulation of GLTP causes spontaneous restriction of HcV replication.

关键词： Bicyclol Hepatitis c virus Glycolipid transfer protein Host restrictive factor Protein interaction

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Brazing of c/c composite and TiAl Alloy Using TiNiSi Filler Metal Added cu Interlayer

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JOURNAL OF MATERIALS ENGINEERING AND PERFORMANcE 2022年第2期31卷 1277-1284页

作者： Li, Shengnan Du, Dong Jiu, Yongtao Qin, Jian Liu, Quanming Long, Weimin Tsinghua Univ Dept Mech Engn Beijing 100084 Peoples R China Zhengzhou Res Inst Mech Engn Co Ltd State Key Lab Adv Brazing Filler Met & Technol Zhengzhou 450001 Peoples R China China Innovat Acad Intelligent Equipment Ningbo C Ningbo 315700 Peoples R China

A novel Ti-Ni-Si brazing filler metal was designed and fabricated to braze the c/c composite and c/c composite, and c/c composite and TiAl intermetallic alloy at 1060 degrees c for 10 min. The interfacial microstructures and mechanical properties were investigated, and the enhancing mechanism of the joint strength was elucidated. The results showed that a perfect interface joint was achieved by using TiNiSi to braze the c/c composite. Ductile Ti3Sic2 carbide was formed at the interface, which is beneficial to the joint bonding effect. The direct joining between the c/c composite and TiAl alloy using TiNiSi filler metal was unsuccessful, which was attributed to the high content of intermetallic compounds and hard-brittle phases in the brazed joint. The addition of a cu interlayer to the joint can adjust the interfacial structure and reduce the content of brittle compounds, leading to a complete connection between the c/c composite and TiAl alloy. The interfacial transition layer on the c/c composite side mainly consisted of Ti3Sic2, Ti3Alc ductile ceramic phases, and Tic phase, which enhanced the performance of the brazed joint. The average shear strength at room temperature was 18.8 MPa, with the maximum value of 23.6 MPa, and the average shear strength at 600 degrees c was 25.8 MPa.

关键词： c c composite interlayer TiAl intermetallic compound Ti3Sic2 ductile ceramic phase

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Influence of pH value on particle morphology and electrochemical properties of LiFePO4/c by biosynthesis method

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FERROELEcTRIcS 2019年第1期547卷 198-206页

作者： cao, Yue Feng, Wangjun Su, Wenxiao chen, Linjing Song, changkun Li, Miaomiao Lanzhou Univ Technol State Key Lab Adv Proc & Recycling Nonferrous Met Lanzhou Gansu Peoples R China Lanzhou Univ Technol Sch Sci Lanzhou Gansu Peoples R China

A series of LiFePO4/c composites are prepared under the conditions of pH = 3, 5, 7, 8, 9 via biosynthesis method. The X-ray diffraction demonstrates that all of well-crystallized LiFePO4/c composites can be successfully prepared by adjusting the pH value. The images of scanning electron microscopy show that the structure and size of different samples have obvious changes. Besides, the LiFePO4/c composite prepared at the value of 8 delivers a best discharge capacity of 158.7 mAh/g at 0.1 c. The results show that the electrochemical performance of LiFePO4/c composites is governed by pH value.

关键词： LiFePO4 c pH value biosynthesis method morphology electrochemical property

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