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Preliminary study on preparation of cell-free system for protein expression

CHEN Haiqin, XU Zhinan, WANG Cheng, CEN Peilin, LIAO Yuhua

《化学科学与工程前沿（英文）》 2008年 第2卷 第2期   页码 224-229 doi: 10.1007/s11705-008-0029-9

摘要： In the new era of “Omics”, the traditional techniques of protein expression in vivo can not come up with the exponential increase of genetic information. The cell-free protein synthesis system provides a new strategy of protein expression with advantages of rapid, convenient and high-throughput expression. The preparation of cell extracts, the optimization of substrate concentrations and the energy regeneration system are the key factors for the successful construction of cell-free protein expression system. In this work, the cell extract was prepared from RNase I- defective strain A19. The cell growth phase, the pressure for cell disruption and the storage condition of cell extracts were optimized. Meanwhile, the optimal substrate concentrations and the energy regeneration system were selected. Under the optimized conditions, the green fluorescent protein (GFP) reporter gene was expressed in the cell-free system with high expression level (Ca. 154 ?g/mL) which was 29 times higher than the expression level before optimization.

关键词： cell-free     regeneration     extract     information     successful construction    

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Cell-free systems in the new age of synthetic biology

Fernando Villarreal,Cheemeng Tan

《化学科学与工程前沿（英文）》 2017年 第11卷 第1期   页码 58-65 doi: 10.1007/s11705-017-1610-x

摘要： The advent of synthetic biology has ushered in new applications of cell-free transcription-translation systems. These cell-free systems are reconstituted using cellular proteins, and are amenable to modular control of their composition. Here, we discuss the historical advancement of cell-free systems, as well as their new applications in the rapid design of synthetic genetic circuits and components, directed evolution of biomolecules, diagnosis of infectious diseases, and synthesis of vaccines. Finally, we present our vision on the future direction of cell-free synthetic biology.

关键词： cell-free system     application    

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Application of liquid biopsy in precision medicine: opportunities and challenges

null

《医学前沿（英文）》 2017年 第11卷 第4期   页码 522-527 doi: 10.1007/s11684-017-0526-7

摘要：

Precision medicine for cancer patients aims to adopt the most suitable treatment options during diagnosis and treatment of individuals. Detecting circulating tumor cell (CTC) or circulating tumor DNA (ctDNA) in plasma or serum could serve as liquid biopsy, which would be useful for numerous diagnostic applications. Liquid biopsies can help clinicians screen and detect cancer early, stratify patients to the most suitable treatment and real-time monitoring of treatment response and resistance mechanisms in the tumor, evaluate the risk for metastatic relapse, and estimate prognosis. We summarized the advantages and disadvantages of tissue and liquid biopsies. We also further compared and analyzed the advantages and limitations of detecting CTCs, ctDNAs, and exosomes. Furthermore, we reviewed the literature related with the application of serum or plasma CTCs, ctDNAs, and exosomes for diagnosis and prognosis of cancer. We also analyzed their opportunities and challenges as future biomarkers. In the future, liquid biopsies could be used to guide cancer treatment. They could also provide the ideal scheme to personalize treatment in precision medicine.

关键词： liquid biopsy     circulating tumor cells     cell-free ctDNA     exosomes     precision medicine    

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Microcystin-LR biodegradation by

Chengbin XIAO, Hai YAN, Junfeng WANG, Wei WEI, Jun NING, Gang PAN

《环境科学与工程前沿（英文）》 2011年 第5卷 第4期   页码 526-532 doi: 10.1007/s11783-010-0261-7

摘要： A promising bacterial strain for biodegrading microcystin-LR (MC-LR) as the sole carbon and nitrogen source was successfully isolated from Lake Dianchi, China. The strain was identified as sp. USTB-05, which was the first isolated MCs-biodegrading sp. in China. The average biodegradation rate of MC-LR by sp. USTB-05 was 28.8 mg·L per day, which was apparently higher than those of other bacteria reported so far. The optimal temperature and pH for both strain USTB-05 growth and MC-LR biodegradation were 30°C and 7.0, respectively. The release of MC-LR from the cyanobacterial cells collected from Lake Guishui and the biodegradation of MC-LR by both strain and cell-free extract (CE) were investigated. The results indicated that MC-LR with the initial concentration of 4.0 mg·L in water was biodegraded by sp. USTB-05 within 4 d, while MC-LR with the initial concentration of 28.8 mg·L could be completely removed in 3 h by CE of sp. USTB-05 containing 350 mg·L protein. During enzymatic biodegradation of MC-LR, two intermediate metabolites and a dead-end product were observed on an HPLC chromatogram. Moreover, the similar scanning profiles of MC-LR and its metabolic products indicate that the Adda side-chain of MC-LR was kept intact in all products.

关键词： microcystin-LR(MC-LR)     biodegradation     Sphingopyxis sp     USTB-05     cell-free extract    

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通过蛋白质工程提高聚酯水解酶对PET 塑料的降解效率 Article

马渊, 姚明东, 李炳志, 丁明珠, 何博, 陈思, 周晓, 元英进

《工程（英文）》 2018年 第4卷 第6期   页码 888-893 doi: 10.1016/j.eng.2018.09.007

摘要：

来自Ideonella sakaiensis 的聚对苯二甲酸乙二醇酯水解酶（PETase）在室温下具有很强的降解聚对苯二甲酸乙二醇酯（PET）的能力，因此被认为是解决聚酯塑料污染问题的潜在工具。在本研究中，基于PETase 和底物2PET 结合时的相互作用模型，分析了PETase 与底物2PET 之间的相互作用，从而对底物结合沟壑周围的六个关键残基进行改造。为了更加快速地筛选突变体酶的活性，本研究利用无细胞蛋白表达体系对设计的PETase 突变体进行高通量的表达和验证。最终发现三种突变体（R61A、L88F 和I179F）的酶活性相比野生型分别提高了1.4 倍、2.1 倍和2.5 倍。其中，I179F突变体的酶活性最高，降解效率为22.5 mg·μmol–1·d–1。因此，本研究通过蛋白质工程对PETase 的关键疏水位点进行设计和改造，获得了降解效果提高的酶突变体，并进一步证实了其生物降解塑料的潜力。

关键词： 聚酯酶     PET降解     无细胞蛋白质合成     聚酯     PET酶    

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6G广域时延敏感物联网——移动边缘计算使能的非地面网络设计 Article

刘承骁, 冯伟, 陶晓明, 葛宁

《工程（英文）》 2022年 第8卷 第1期   页码 96-107 doi: 10.1016/j.eng.2021.11.002

摘要：

在即将到来的第六代移动通信技术（6G）时代，广域时延敏感物联网（IoT）需求不断增加。由于传统蜂窝技术难以直接用于广域时延敏感IoT，因此使用非地面基础设施，包括卫星和无人机（UAV）等，基于无蜂窝网络架构构建非地面网络（NTN）亟待研究。考虑到时延敏感业务需求和IoT 设备分布不均的特点，NTN可使用移动边缘计算（MEC）来增强业务支持能力，并提供“沙漠绿洲”状（oasis-oriented）的按需覆盖。然而，在MEC使能的NTN中，通信和MEC系统相互耦合，带来通信与计算资源协同编排难题。本文提出一种面向过程的优化框架，在更大时间尺度上设计通信和MEC系统。在这个框架中，本研究采用大尺度信道状态信息（CSI）刻画复杂传播环境，构建通信与计算资源联合编排的时延最小化问题；给出该优化问题的近似问题，并将其分解为多个子问题；然后，提出迭代算法来求解这些子问题。仿真结果表明，与现有算法相比，所提出的面向过程的方案可以降低任务总时延。这为无人机载荷部署提供了依据，也显示了在广域时延敏感IoT中NTN与MEC协同设计的潜力。

关键词： 无蜂窝     移动边缘计算     非地面网络     第六代移动通信技术     广域时延敏感物联网    

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A space power system of free piston Stirling generator based on potassium heat pipe

Mingqiang LIN, Jian MOU, Chunyun CHI, Guotong HONG, Panhe GE, Gu HU

《能源前沿（英文）》 2020年 第14卷 第1期   页码 1-10 doi: 10.1007/s11708-019-0655-6

摘要： The power system of a free piston Stirling generator (FPSG) based on potassium heat pipes has been developed in this paper. Thanks to the advantages of long life, high reliability, and high overall thermal efficiency, the FPSG is a promising candidate for nuclear energy, especially in space exploration. In this paper, the recent progress of FPSG based on nuclear reactor for space use was briefly reviewed. A novel FPSG weighted only 4.2 kg was designed, and one dimensional thermodynamic modeling of the FPSG using Sage software was performed to estimate its performance. The experiment results indicated that this FPSG could provide 142.4 W at a thermal-to-electric efficiency of nearly 17.4%. Besides, the power system integrated with four FPSGs and potassium heat pipes was performed and the single machine failure test was conducted. The results show that this system could provide an electrical power of 300 W at an overall thermal efficiency of 7.3%. Thus, it is concluded that this power system is feasible and will have a great prospect for future applications.

关键词： free piston Stirling generator (FPSG)     potassium heat pipe     power system     energy conversion    

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An extended cell-based smoothed discrete shear gap method (XCS-FEM-DSG3) for free vibration analysis

M. H. NGUYEN-THOI,L. Le-ANH,V. Ho-HUU,H. Dang-TRUNG,T. NGUYEN-THOI

《结构与土木工程前沿（英文）》 2015年 第9卷 第4期   页码 341-358 doi: 10.1007/s11709-015-0302-1

摘要： A cell-based smoothed discrete shear gap method (CS-FEM-DSG3) was recently proposed and proven to be robust for free vibration analyses of Reissner-Mindlin shell. The method improves significantly the accuracy of the solution due to softening effect of the cell-based strain smoothing technique. In addition, due to using only three-node triangular elements generated automatically, the CS-FEM-DSG3 can be applied flexibly for arbitrary complicated geometric domains. However so far, the CS-FEM-DSG3 has been only developed for analyzing intact structures without possessing internal cracks. The paper hence tries to extend the CS-FEM-DSG3 for free vibration analysis of cracked Reissner-Mindlin shells by integrating the original CS-FEM-DSG3 with discontinuous and crack−tip singular enrichment functions of the extended finite element method (XFEM) to give a so-called extended cell-based smoothed discrete shear gap method (XCS-FEM-DSG3). The accuracy and reliability of the novel XCS-FEM-DSG3 for free vibration analysis of cracked Reissner-Mindlin shells are investigated through solving three numerical examples and comparing with commercial software ANSYS.

关键词： cracked Reissner-Mindlin shell     free vibration analysis     cell-based smoothed discrete shear gap method (CS-FEM-DSG3)     extended cell-based smoothed discrete shear gap method (XCS-FEM-DSG3)     smoothed finite element methods (SFEM)    

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NADPH oxidase and reactive oxygen species as signaling molecules in carcinogenesis

Gang WANG

《医学前沿（英文）》 2009年 第3卷 第1期   页码 1-7 doi: 10.1007/s11684-009-0018-5

摘要： Reactive oxygen species (ROS) are small molecule metabolites of oxygen that are prone to participate in redox reactions their high reactivity. Intracellular ROS could be generated in reduced nicotinamide-adenine dinucleotidephosphate (NADPH) oxidase-dependent and/or NADPH oxidase-independent manners. Physiologically, ROS are involved in many signaling cascades that contribute to normal processes. One classical example is that ROS derived from the NADPH oxidase and released in neurotrophils are able to digest invading bacteria. Excessive ROS, however, contribute to pathogenesis of various human diseases including cancer, aging, dimentia and hypertension. As signaling messengers, ROS are able to oxidize many targets such as DNA, proteins and lipids, which may be linked with tumor growth, invasion or metastasis. The present review summarizes recent advances in our comprehensive understanding of ROS-linked signaling pathways in regulation of tumor growth, invasion and metastasis, and focuses on the role of the NADPH oxidase-derived ROS in cancer pathogenesis.

关键词： free radicals     tumor     phox     cell proliferation     cancer therapy    

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Design and modeling of a free-piston engine generator

《能源前沿（英文）》   页码 811-821 doi: 10.1007/s11708-022-0848-2

摘要： Free-piston engine generators (FPEGs) can be applied as decarbonized range extenders for electric vehicles because of their high thermal efficiency, low friction loss, and ultimate fuel flexibility. In this paper, a parameter-decoupling approach is proposed to model the design of an FPEG. The parameter-decoupling approach first divides the FPEG into three parts: a two-stroke engine, an integrated scavenging pump, and a linear permanent magnet synchronous machine (LPMSM). Then, each of these is designed according to predefined specifications and performance targets. Using this decoupling approach, a numerical model of the FPEG, including the three aforementioned parts, was developed. Empirical equations were adopted to design the engine and scavenging pump, while special considerations were applied for the LPMSM. A finite element model with a multi-objective genetic algorithm was adopted for its design. The finite element model results were fed back to the numerical model to update the LPMSM with increased fidelity. The designed FPEG produced 10.2 kW of electric power with an overall system efficiency of 38.5% in a stable manner. The model provides a solid foundation for the manufacturing of related FPEG prototypes.

关键词： free-piston engine generator     linear permanent magnet synchronous machine     system design     numerical model     finite element method    

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Comparison of reference values for immune recovery between event-free patients receiving haploidentical

null

《医学前沿（英文）》 2018年 第12卷 第2期   页码 153-163 doi: 10.1007/s11684-017-0548-1

摘要：

To establish optimal reference values for recovered immune cell subsets, we prospectively investigated post-transplant immune reconstitution (IR) in 144 patients who received allogeneic stem cell transplantation (allo-SCT) and without showing any of the following events: poor graft function, grades II?IV acute graft-versus-host disease (GVHD), serious chronic GVHD, serious bacterial infection, invasive fungal infection, or relapse or death in the first year after transplantation. IR was rapid in monocytes, intermediate in lymphocytes, CD3+ T cells, CD8+ T cells, and CD19+ B cells, and very slow in CD4+ T cells in the entire patient cohort. Immune recovery was generally faster under HLA-matched sibling donor transplantation than under haploidentical transplantation. Results suggest that patients with an IR comparable to the reference values display superior survival, and the levels of recovery in immune cells need not reach those in healthy donor in the first year after transplantation. We suggest that data from this recipient cohort should be used as reference values for post-transplant immune cell counts in patients receiving HSCT.

关键词： immune reconstitution     hematopoietic stem cell transplantation     event-free patients     reference range    

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The ecological adaptability of cloned sheep to free-grazing in the Tengger Desert of Inner Mongolia,

Xinxin LI,Huijuan WANG,Guanghua SU,Zhuying WEI,Chunling BAI,Wuni-MENGHE,Yanhui HOU,Changqing YU,Shorgan BOU,Guangpeng LI

《农业科学与工程前沿（英文）》 2014年 第1卷 第3期   页码 191-200 doi: 10.15302/J-FASE-2014029

摘要： Since the birth of the first cloned sheep, somatic cell nuclear transfer technology has been successfully used to clone a variety of mammals. Cloned livestock have no apparent health risks, and the quality and safety of the cloned animal products are similar to non-cloned animals. The social behavior and environmental adaptability of postnatal cloned animals, especially when used for grassland farm production purposes, is unknown. In the present study, the cloned Dorper sheep equipped with GPS location devices were free-grazed in a harsh natural environment similar to conditions commonly experienced by Mongolian sheep. The main findings of this research were as follows. (1) Under free-grazing conditions, the cloned sheep showed excellent climatic and ecological adaptability. In extreme temperature conditions ranging from -30 to 40°C, the cloned sheep maintained acceptable body condition and behaved as other sheep. (2) The cloned sheep quickly adapted from a herd feeding strategy to the harsh environment and quickly exhibited a grazing regimen as other free-grazing sheep. (3) The cloned sheep exhibited free-grazing patterns and social behavior as other sheep. (4) The cloned sheep in the harsh environment thrived and produced healthy lambs. Overall, the cloned Dorper sheep exhibited excellent ecological adaptation, which is an important consideration for breeding meat sheep by cloning. The Dorper sheep readily adapted to the free-grazing conditions on the Mongolian plateau grassland, which attests to their ability to withstand harsh environmental conditions.

关键词： somatic cell nuclear transfer     free-grazing synchronization     Dorper sheep     cloned animal ecology    

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Risk stratification system for skin and soft tissue infections after allogeneic hematopoietic stem cell

《医学前沿（英文）》 2022年 第16卷 第6期   页码 957-968 doi: 10.1007/s11684-021-0910-1

摘要： Skin and soft tissue infections (SSTIs) refer to infections involving the skin, subcutaneous tissue, fascia, and muscle. In transplant populations with hematological malignancies, an immunocompromised status and the routine use of immunosuppressants increase the risk of SSTIs greatly. However, to date, the profiles and clinical outcomes of SSTIs in hematopoietic stem cell transplantation (HSCT) patients remain unclear. This study included 228 patients (3.67%) who developed SSTIs within 180 days after allogeneic HSCT from January 2004 to December 2019 in Peking University People’s Hospital. The overall annual survival rate was 71.5%. We compared the differences between survivors and non-survivors a year after transplant and found that primary platelet graft failure (PPGF), comorbidities of acute kidney injury (AKI), and hospital-acquired pneumonia (HAP) were independent risk factors for death in the study population. A PPGF–AKI–HAP risk stratification system was established with a mortality risk score of 1×PPGF+1×AKI+1×HAP. The areas under the curves of internal and external validation were 0.833 (95% CI 0.760–0.906) and 0.826 (95% CI 0.715–0.937), respectively. The calibration plot revealed the high consistency of the estimated risks, and decision curve analysis showed considerable net benefits for patients.

关键词： skin and soft tissue infections     hematopoietic stem cell transplantation     risk stratification system     mortality    

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Piezoelectric pump with flexible venous valves for active cell transmission

《机械工程前沿（英文）》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0712-4

摘要： The development of organ-on-a-chip systems demands high requirements for adequate micro-pump performance, which needs excellent performance and effective transport of active cells. In this study, we designed a piezoelectric pump with a flexible venous valve inspired by that of humans. Performance test of the proposed pump with deionized water as the transmission medium shows a maximum output flow rate of 14.95 mL/min when the input voltage is 100 V, and the pump can transfer aqueous solutions of glycerol with a viscosity of 10.8 mPa·s. Cell survival rate can reach 97.22% with a yeast cell culture solution as the transmission medium. A computational model of the electric-solid-liquid multi-physical field coupling of the piezoelectric pump with a flexible venous valve is established, and simulation results are consistent with experimental results. The proposed pump can help to construct the circulating organ-on-a-chip system, and the simple structure and portable application can enrich the design of microfluidic systems. In addition, the multi-physical field coupling computational model established for the proposed piezoelectric pump can provide an in-depth study of the characteristics of the flow field, facilitating the optimal design of the micro-pump and providing a reference for the further study of active cell transport in organ-on-a-chip systems.

关键词： venous valve     flexible venous valve     cell transmission     organ-on-a-chip system     piezoelectric device    

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Nitrogen-doped graphene approach to enhance the performance of a membraneless enzymatic biofuel cell

Alireza AHMADIAN YAZDI, Jie XU

《能源前沿（英文）》 2018年 第12卷 第2期   页码 233-238 doi: 10.1007/s11708-018-0529-3

摘要： Heteroatom-doping of pristine graphene is an effective route for tailoring new characteristics in terms of catalytic performance which opens up potentials for new applications in energy conversion and storage devices. Nitrogen-doped graphene (N-graphene), for instance, has shown excellent performance in many electrochemical systems involving oxygen reduction reaction (ORR), and more recently glucose oxidation. Owing to the excellent sensitivity of N-graphene, the development of highly sensitive and fast-response enzymatic biosensors is made possible. However, a question that needs to be addressed is whether or not improving the anodic response to glucose detection leads to a higher overall performance of enzymatic biofuel cell (eBFC). Thus, here we first synthesized N-graphene via a catalyst-free single-step thermal process, and made use of it as the biocatalyst support in a membraneless eBFC to identify its role in altering the performance characteristics. Our findings demonstrate that the electron accepting nitrogen sites in the graphene structure enhances the electron transfer efficiency between the mediator (redox polymer), redox active site of the enzymes, and electrode surface. Moreover, the best performance in terms of power output and current density of eBFCs was observed when the bioanode was modified with highly doped N-graphene.

关键词： enzymatic fuel cell     nitrogen-doped graphene     reduced graphene oxide     catalyst-free synthesis    

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标题 作者 时间 类型 操作

Preliminary study on preparation of cell-free system for protein expression

CHEN Haiqin, XU Zhinan, WANG Cheng, CEN Peilin, LIAO Yuhua

期刊论文

Cell-free systems in the new age of synthetic biology

Fernando Villarreal,Cheemeng Tan

期刊论文

Application of liquid biopsy in precision medicine: opportunities and challenges

null

期刊论文

Microcystin-LR biodegradation by

Chengbin XIAO, Hai YAN, Junfeng WANG, Wei WEI, Jun NING, Gang PAN

期刊论文

通过蛋白质工程提高聚酯水解酶对PET 塑料的降解效率

马渊, 姚明东, 李炳志, 丁明珠, 何博, 陈思, 周晓, 元英进

期刊论文

6G广域时延敏感物联网——移动边缘计算使能的非地面网络设计

刘承骁, 冯伟, 陶晓明, 葛宁

期刊论文

A space power system of free piston Stirling generator based on potassium heat pipe

Mingqiang LIN, Jian MOU, Chunyun CHI, Guotong HONG, Panhe GE, Gu HU

期刊论文

An extended cell-based smoothed discrete shear gap method (XCS-FEM-DSG3) for free vibration analysis

M. H. NGUYEN-THOI,L. Le-ANH,V. Ho-HUU,H. Dang-TRUNG,T. NGUYEN-THOI

期刊论文

NADPH oxidase and reactive oxygen species as signaling molecules in carcinogenesis

Gang WANG

期刊论文

Design and modeling of a free-piston engine generator

期刊论文

Comparison of reference values for immune recovery between event-free patients receiving haploidentical

null

期刊论文

The ecological adaptability of cloned sheep to free-grazing in the Tengger Desert of Inner Mongolia,

Xinxin LI,Huijuan WANG,Guanghua SU,Zhuying WEI,Chunling BAI,Wuni-MENGHE,Yanhui HOU,Changqing YU,Shorgan BOU,Guangpeng LI

期刊论文

Risk stratification system for skin and soft tissue infections after allogeneic hematopoietic stem cell

期刊论文

Piezoelectric pump with flexible venous valves for active cell transmission

期刊论文

Nitrogen-doped graphene approach to enhance the performance of a membraneless enzymatic biofuel cell

Alireza AHMADIAN YAZDI, Jie XU

期刊论文