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Synthesis and characterization of well-defined comb-like branched polymers

LI Aixiang, LU Zaijun, LÜ Zijian

《化学科学与工程前沿(英文)》 2008年 第2卷 第4期   页码 407-411 doi: 10.1007/s11705-008-0064-6

摘要: Well-defined comb-like branched polymers having one branch in each repeating unit have been successfully synthesized by the coupling reaction of living polystyrene (PS) and polyisoprene (PI) anions with 1, 1-diphenylethenyl (DPE) groups along PS backbone prepared via atom transfer radical polymerization (ATRP) of 4-vinylbenzyloxy benzophenone (Sc) followed by Wittig reaction. The resulting comb-like branched polymers were characterized by IR, H-NMR, gel permeation chromatography (GPC) and static light scattering (SLS) in detail. The effect of living chains and DPE group molar ratio on grafting efficiency was discussed. The results show the coupling reaction of living chains and DPE groups was highly effective, and the coupling efficiency can be controlled via the feed molar ratios of living chains and DPE groups. Moreover, the effect of molecular weights of backbone (PSe) and PSLi or PILi on grafting efficiency was also discussed. The results show that when excess living polymers were used, the almost quantitative grafting efficiency could be achieved.

关键词: grafting efficiency     polyisoprene     quantitative grafting     effective     molecular    

Fabrication of high-capacity cation-exchangers for protein adsorption: Comparison of grafting-from andgrafting-to approaches

Ming Zhao, Run Liu, Jian Luo, Yan Sun, Qinghong Shi

《化学科学与工程前沿(英文)》 2019年 第13卷 第1期   页码 120-132 doi: 10.1007/s11705-018-1730-y

摘要: In this work, we have synthesized two polymer-grafted cation exchangers: one via the grafting-from approach, in which sulfopropyl methacrylate (SPM) is grafted through atom transfer radical polymerization onto Sepharose FF (the thus resulting exchanger is referred as Sep- -SPM), and another via the grafting-to approach, in which the polymer of SPM is directly coupled onto Sepharose FF (the thus resulting exchanger is called as Sep- SPM). Protein adsorption on these two cation exchangers have been also investigated. At the same ligand density, Sep- -SPM has a larger accessible pore radius and a smaller depth of polymer layer than Sep- SPM, due to the controllable introduction of polymer chains with the regular distribution of the ligand. Therefore, high-capacity adsorption of lysozyme and -globulin could be achieved simultaneously in Sep- -SPM with an ionic capacity (IC) of 308 mmol·L . However, Sep- SPM has an irregular chain distribution and different architecture of polymer layer, which lead to more serious repulsive interaction to proteins, and thus Sep- SPM has a lower adsorption capacity for -globulin than Sep- -SPM with the similar IC. Moreover, the results from protein uptake experiments indicate that the facilitated transport of adsorbed -globulin occurs only in Sep- SPM and depends on the architecture of polymer layers. Our research provides a clear clue for the development of high-performance protein chromatography.

关键词: polymer-grafted ionic exchanger     grafting technique     protein adsorption     atom transfer radical polymerization     γ-globulin    

Liver cell therapies: cellular sources and grafting strategies

《医学前沿(英文)》 2023年 第17卷 第3期   页码 432-457 doi: 10.1007/s11684-023-1002-1

摘要: The liver has a complex cellular composition and a remarkable regenerative capacity. The primary cell types in the liver are two parenchymal cell populations, hepatocytes and cholangiocytes, that perform most of the functions of the liver and that are helped through interactions with non-parenchymal cell types comprising stellate cells, endothelia and various hemopoietic cell populations. The regulation of the cells in the liver is mediated by an insoluble complex of proteins and carbohydrates, the extracellular matrix, working synergistically with soluble paracrine and systemic signals. In recent years, with the rapid development of genetic sequencing technologies, research on the liver’s cellular composition and its regulatory mechanisms during various conditions has been extensively explored. Meanwhile breakthroughs in strategies for cell transplantation are enabling a future in which there can be a rescue of patients with end-stage liver diseases, offering potential solutions to the chronic shortage of livers and alternatives to liver transplantation. This review will focus on the cellular mechanisms of liver homeostasis and how to select ideal sources of cells to be transplanted to achieve liver regeneration and repair. Recent advances are summarized for promoting the treatment of end-stage liver diseases by forms of cell transplantation that now include grafting strategies.

关键词: liver regeneration     hepatocytes     cholangiocytes     stem cells     organoids     regulatory mechanisms     transplantation/grafting strategies    

Trihydrazinotriazine-grafting Fe

Jamal Rahimi, Seyedeh Shadi Mirmohammadi, Ali Maleki

《化学科学与工程前沿(英文)》 2021年 第15卷 第4期   页码 1008-1020 doi: 10.1007/s11705-020-1996-8

摘要: This study focuses on the synthesis and characterization of a novel magnetic nanocomposite 2,4,6-trihydrazino-1,3,5-triazine (THDT)-functionalized with silica-coated iron oxide magnetic nanoparticles (MNPs). This nanocomposite has porous morphology decorated with the spherical MNPs. Through co-precipitation of iron salts, MNPs were obtained. The prepared THDT was placed on the chlorine surface-modified MNPs. The present environment-friendly nanocatalyst intensely accelerated the synthesis of highly functionalized tetrahydrobenzo[ ]pyran derivatives as well as reduced the reaction times and increased yields of the products.

关键词: trihydrazino-triazine     porous     magnetic nanocatalyst     green chemistry     tetrahydrobenzo[b]pyrans    

SinoSCORE: a logistically derived additive prediction model for post-coronary artery bypass grafting

null

《医学前沿(英文)》 2013年 第7卷 第4期   页码 477-485 doi: 10.1007/s11684-013-0284-0

摘要:

This study aims to construct a logistically derived additive score for predicting in-hospital mortality risk in Chinese patients undergoing coronary artery bypass surgery (CABG). Data from 9839 consecutive CABG patients in 43 Chinese centers were collected between 2007 and 2008 from the Chinese Coronary Artery Bypass Grafting Registry. This database was randomly divided into developmental and validation subsets (9:1). The data in the developmental dataset were used to develop the model using logistic regression. Calibration and discrimination characteristics were assessed using the validation dataset. Thresholds were defined for each model to distinguish different risk groups. After excluding 275 patients with incomplete information, the overall mortality rate of the remaining 9564 patients was 2.5%. The SinoSCORE model was constructed based on 11 variables: age, preoperative NYHA stage III or IV, chronic renal failure, extracardiac arteriopathy, chronic obstructive pulmonary disease, preoperative atrial fibrillation or flutter (within 2βweeks), left ventricular ejection fraction, other elective surgery, combined valve procedures, preoperative critical state, and BMI. In the developmental dataset, calibration using a Hosmer-Lemeshow (HL) test was at =β0.44 and discrimination based on the area under the receiver operating characteristic curve (ROC) was 0.80. In the validation dataset, the HL test was at =β0.34 and the area under the ROC (AUC) was 0.78. A logistically derived additive model for predicting in-hospital mortality among Chinese patients undergoing CABG was developed based on the most up-to-date multi-center data from China.

关键词: coronary artery bypass grafting     risk stratification     in-hospital mortality    

Enhanced permeability and biofouling mitigation of forward osmosis membranes via grafting graphene quantum

《化学科学与工程前沿(英文)》 2023年 第17卷 第10期   页码 1470-1483 doi: 10.1007/s11705-023-2329-5

摘要: In this paper, graphene oxide quantum dots with amino groups (NH2-GOQDs) were tailored to the surface of a thin-film composite (TFC) membrane surface for optimizing forward osmosis (FO) membrane performance using the amide coupling reaction. The results jointly demonstrated hydrophilicity and surface roughness of the membrane enhanced after grafting NH2-GOQDs, leading to the optimized affinity and the contact area between the membrane and water molecules. Therefore, grafting of the membrane with a concentration of 100 ppm (TFC-100) exhibited excellent permeability performance (58.32 L·m–2·h–1) compared with TFC membrane (16.94 L·m–2·h–1). In the evaluation of static antibacterial properties of membranes, TFC-100 membrane destroyed the cell morphology of Escherichia coli (E. coli) and reduced the degree of bacterial adsorption. In the dynamic biofouling experiment, TFC-100 membrane showed a lower flux decline than TFC membrane. After the physical cleaning, the flux of TFC-100 membrane could recover to 96% of the initial flux, which was notably better than that of TFC membrane (63%). Additionally, the extended Derjaguin–Landau–Verwey–Overbeek analysis of the affinity between pollutants and membrane surface verified that NH2-GOQDs alleviates E. coli contamination of membrane. This work highlights the potential applications of NH2-GOQDs for optimizing permeability and biofouling mitigation of FO membranes.

关键词: forward osmosis membrane     graphene oxide quantum dots     graft modification     anti-fouling membrane     XDLVO theory    

A computational toolbox for molecular property prediction based on quantum mechanics and quantitative

《化学科学与工程前沿(英文)》 2022年 第16卷 第2期   页码 152-167 doi: 10.1007/s11705-021-2060-z

摘要: Chemical industry is always seeking opportunities to efficiently and economically convert raw materials to commodity chemicals and higher value-added chemical-based products. The life cycles of chemical products involve the procedures of conceptual product designs, experimental investigations, sustainable manufactures through appropriate chemical processes and waste disposals. During these periods, one of the most important keys is the molecular property prediction models associating molecular structures with product properties. In this paper, a framework combining quantum mechanics and quantitative structure-property relationship is established for fast molecular property predictions, such as activity coefficient, and so forth. The workflow of framework consists of three steps. In the first step, a database is created for collections of basic molecular information; in the second step, quantum mechanics-based calculations are performed to predict quantum mechanics-based/derived molecular properties (pseudo experimental data), which are stored in a database and further provided for the developments of quantitative structure-property relationship methods for fast predictions of properties in the third step. The whole framework has been carried out within a molecular property prediction toolbox. Two case studies highlighting different aspects of the toolbox involving the predictions of heats of reaction and solid-liquid phase equilibriums are presented.

关键词: molecular property     quantum mechanics     quantitative structure-property relationship     heat of reaction     solid-liquid phase equilibrium    

Erratum to: Using pyrosequencing and quantitative PCR to analyze microbial communities

Husen ZHANG

《环境科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 488-488 doi: 10.1007/s11783-011-0342-2

Estimation of photolysis half-lives of dyes in a continuous-flow system with the aid of quantitative

Davoud BEIKNEJAD,Mohammad Javad CHAICHI

《环境科学与工程前沿(英文)》 2014年 第8卷 第5期   页码 683-692 doi: 10.1007/s11783-014-0680-y

摘要: In this paper the photolysis half-lives of the model dyes in water solutions and under ultraviolet (UV) radiation were determined by using a continuous-flow spectrophotometric method. A quantitative structure-property relationship (QSPR) study was carried out using 21 descriptors based on different chemometric tools including stepwise multiple linear regression (MLR) and partial least squares (PLS) for the prediction of the photolysis half-life ( ) of dyes. For the selection of test set compounds, a K-means clustering technique was used to classify the entire data set, so that all clusters were properly represented in both training and test sets. The QSPR results obtained with these models show that in MLR-derived model, photolysis half-lives of dyes depended strongly on energy of the highest occupied molecular orbital ( ), largest electron density of an atom in the molecule ( ) and lipophilicity (log ). While in the model derived from PLS, besides aforementioned and descriptors, the molecular surface area ( ), molecular weight ( ), electronegativity ( ), energy of the second highest occupied molecular orbital ( ) and dipole moment ( ) had dominant effects on logt values of dyes. These were applicable for all classes of studied dyes (including monoazo, disazo, oxazine, sulfonephthaleins and derivatives of fluorescein). The results were also assessed for their consistency with findings from other similar studies.

关键词: dye     photolysis half-life     quantitative structure-property relationship     continuous-flow     stepwise multiple linear regression     partial least squares    

Application of quantum chemical descriptors into quantitative structure-property relationship models

Yueping BAO, Qiuying HUANG, Wenlong WANG, Jiangjie XU, Fan JIANG, Chenghong FENG

《环境科学与工程前沿(英文)》 2011年 第5卷 第4期   页码 505-511 doi: 10.1007/s11783-011-0318-2

摘要: Quantitative structure-property relationship (QSPR) models were developed for prediction of photolysis half-life ( ) of polychlorinated biphenyls (PCBs) in water under ultraviolet (UV) radiation. Quantum chemical descriptors computed by the PM3 Hamiltonian software were used as independent variables. The cross-validated value for the optimal QSPR model is 0.966, indicating good prediction capability for lg values of PCBs in water. The QSPR results show that the largest negative atomic charge on a carbon atom ( ) and the standard heat of formation (Δ ) have a dominant effect on values of PCBs. Higher values or lower Δ values of the PCBs leads to higher lg values. In addition, the lg values of PCBs increase with the increase in the energy of the highest occupied molecular orbital values. Increasing the largest positive atomic charge on a chlorine atom and the most positive net atomic charge on a hydrogen atom in PCBs leads to the decrease of lg values.

关键词: photolysis     polychlorinated biphenyls (PCBs)     quantitative structure-property relationships (QSPRs)     quantum chemical descriptors    

Design and use of group-specific primers and probes for real-time quantitative PCR

Juntaek LIM, Seung Gu SHIN, Seungyong LEE, Seokhwan HWANG

《环境科学与工程前沿(英文)》 2011年 第5卷 第1期   页码 28-39 doi: 10.1007/s11783-011-0302-x

摘要: Real-time quantitative polymerase chain reaction (qPCR) has gained popularity as a technique to detect and quantify a specific group of target microorganisms from various environmental samples including soil, water, sediments, and sludge. Although qPCR is a very useful technique for nucleic acid quantification, accurately quantifying the target microbial group strongly depends on the quality of the primer and probe used. Many aspects of conducting qPCR assays have become increasingly routine and automated; however, one of the most important aspects, designing and selecting primer and probe sets, is often a somewhat arcane process. In many cases, failed or non-specific amplification can be attributed to improperly designed primer-probe sets. This paper is intended to provide guidelines and general principles for designing group-specific primers and probes for qPCR assays. We demonstrate the effectiveness of these guidelines by reviewing the use of qPCR to study anaerobic processes and biologic nutrient removal processes. qPCR assays using group-specific primers and probes designed with this method, have been used to successfully quantify 16S ribosomal Ribonucleic Acid (16S rRNA) gene copy numbers from target methanogenic and ammonia- oxidizing bacteria in various laboratory- and full-scale biologic processes. Researchers with a good command of primer and probe design can use qPCR as a valuable tool to study biodiversity and to develop more efficient control strategies for biologic processes.

关键词: absolute quantification     design guideline     primer     probe     real-time quantitative polymerase chain reaction (qPCR)    

Quantitative analysis of CO

Xianbing LIU, Can WANG

《环境科学与工程前沿(英文)》 2009年 第3卷 第1期   页码 12-19 doi: 10.1007/s11783-009-0011-x

摘要: The increasing volume of CO embodiment in international trade adds a layer of complexity to environmental policies and has raised arguments on the traditional production based responsibility for CO emissions. In order to help understand the quantity of CO embodiment in trade and its policy implications, this paper gives observations to recently emerging literatures that quantitatively discuss CO embodiment in trade. The analytical approaches share the principle of using input and output modeling but vary dramatically in study boundary and estimation accuracy. The calculations can be roughly categorized into three types: direct quantification of CO embodiments in multiregional trade, direct quantification of CO embodiment in bilateral trade, and indirect analysis by comparing the scenarios with or without trade. The practical estimations strongly rely on trade partner selection and data availability. An obvious imbalance of net CO embodiment in the commodity trade between major developed countries and developing economies as a whole was confirmed by these literatures. Carbon taxes and other possible limitations on CO emissions have been addressed. The consistency across the calculations could be enhanced by systematic analyses in more detail to convince the international community to take binding commitments for the reduction of global CO emissions.

关键词: CO2 embodiment     international trade     quantitative estimation     analytical approach    

Using pyrosequencing and quantitative PCR to analyze microbial communities

Husen ZHANG

《环境科学与工程前沿(英文)》 2011年 第5卷 第1期   页码 21-27 doi: 10.1007/s11783-011-0303-9

摘要: New high-throughput technologies continue to emerge for studying complex microbial communities. In particular, massively parallel pyrosequencing enables very high numbers of sequences, providing a more complete view of community structures and a more accurate inference of the functions than has been possible just a few years ago. In parallel, quantitative real-time polymerase chain reaction (QPCR) allows quantitative monitoring of specific community members over time, space, or different environmental conditions. In this review, the principles of these two methods and their complementary applications in studying microbial ecology in bioenvironmental systems are discussed. The parallel sequencing of amplicon libraries and using barcodes to differentiate multiple samples in a pyrosequencing run are explained. The best procedures and chemistries for QPCR amplifications are also described and advantages of applying automation to increase accuracy are addressed. Three examples in which pyrosequencing and QPCR were used together to define and quantify members of microbial communities are provided: in the human large intestine, in a methanogenic digester whose sludge was made more bioavailable by a high-voltage pretreatment, and on the biofilm anode of a microbial electrolytic cell. The key findings in these systems and how both methods were used in concert to achieve those findings are highlighted.

关键词: polymerase chain reaction (PCR)     microbial communities     pyrosequencing     gut     microbial fuel cell     sludge    

Decoding and quantitative detection of antibiotics by a luminescent mixed-lanthanide-organic framework

《环境科学与工程前沿(英文)》 2022年 第16卷 第12期 doi: 10.1007/s11783-022-1589-5

摘要:

● A series of mixed-LOFs and portable LOF-fibers were synthesized.

关键词: Antibiotics     Sensor     Luminescence     Lanthanide-organic frameworks    

Contemporary coronary artery bypass grafting

null

《医学前沿(英文)》 2014年 第8卷 第4期   页码 395-398 doi: 10.1007/s11684-014-0374-7

摘要:

Current evidence clearly demonstrates that coronary artery bypass grafting (CABG) remains the “gold standard” treatment for most patients with multivessel and left main stem disease. This article summarizes the relevant evidence basis demonstrating that CABG, in comparison to stenting, reduces mortality and subsequent myocardial infarction and the need for repeat revascularization. The article also describes the evidence basis to support the use of more arterial grafts during CABG and the current role of off-pump CABG.

关键词: coronary artery bypass grafting (CABG)     coronary artery disease     left main     arterial grafts     internal mammary artery     off-pump CABG    

标题 作者 时间 类型 操作

Synthesis and characterization of well-defined comb-like branched polymers

LI Aixiang, LU Zaijun, LÜ Zijian

期刊论文

Fabrication of high-capacity cation-exchangers for protein adsorption: Comparison of grafting-from andgrafting-to approaches

Ming Zhao, Run Liu, Jian Luo, Yan Sun, Qinghong Shi

期刊论文

Liver cell therapies: cellular sources and grafting strategies

期刊论文

Trihydrazinotriazine-grafting Fe

Jamal Rahimi, Seyedeh Shadi Mirmohammadi, Ali Maleki

期刊论文

SinoSCORE: a logistically derived additive prediction model for post-coronary artery bypass grafting

null

期刊论文

Enhanced permeability and biofouling mitigation of forward osmosis membranes via grafting graphene quantum

期刊论文

A computational toolbox for molecular property prediction based on quantum mechanics and quantitative

期刊论文

Erratum to: Using pyrosequencing and quantitative PCR to analyze microbial communities

Husen ZHANG

期刊论文

Estimation of photolysis half-lives of dyes in a continuous-flow system with the aid of quantitative

Davoud BEIKNEJAD,Mohammad Javad CHAICHI

期刊论文

Application of quantum chemical descriptors into quantitative structure-property relationship models

Yueping BAO, Qiuying HUANG, Wenlong WANG, Jiangjie XU, Fan JIANG, Chenghong FENG

期刊论文

Design and use of group-specific primers and probes for real-time quantitative PCR

Juntaek LIM, Seung Gu SHIN, Seungyong LEE, Seokhwan HWANG

期刊论文

Quantitative analysis of CO

Xianbing LIU, Can WANG

期刊论文

Using pyrosequencing and quantitative PCR to analyze microbial communities

Husen ZHANG

期刊论文

Decoding and quantitative detection of antibiotics by a luminescent mixed-lanthanide-organic framework

期刊论文

Contemporary coronary artery bypass grafting

null

期刊论文