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Synthesis of depsipeptides from

Hongfei CAO, Yakai FENG, Heyun WANG, Li ZHANG, Musammir KHAN, Jintang GUO

《化学科学与工程前沿（英文）》 2011年第5卷第4期页码 409-415 doi: 10.1007/s11705-011-1141-9

摘要： By using the corresponding -amino acid sodium as initiator, -caprolactone-depsipeptides CL-Ala and CL-Leu were prepared by the reactions of -caprolactone (CL) with -alanine and -leucine, respectively, and -dioxanone-depsipeptide (PDO-Leu) was prepared by the reaction of -dioxanone (PDO) with -leucine. Two poly( -caprolactone) oligomers (PCL-Ala and PCL-Leu) of different molecular weights with depsipeptide unit were synthesized by controlling the feed ratio of -amino acid sodium and CL. The presence of the depsipeptide structure in these obtained products was confirmed by H NMR spectra and the molecular weight of the poly( -caprolactone) oligomers was measured by gel permeation chromatography (GPC). These products contain a hydroxyl group and a carboxyl group in one molecule, which means they could act as bifunctional monomers for further polymerization to prepare high molecular weight polymers. By this way, the depsipeptide unit could be introduced into the polymers and the biodegradation rates of the novel polymers could be well controlled in vivo by the tailored molecular structures.

关键词： ?-caprolactone p-dioxanone L-alanine L-leucine depsipeptide

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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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Glucagon-like peptide-2 exhibits protective effect on hepatic ischemia-reperfusion injury in rats

null

《医学前沿（英文）》 2015年第9卷第3期页码 368-373 doi: 10.1007/s11684-015-0403-1

摘要：

Glucagon-like peptide-2 (GLP-2) has potent anti-inflammatory effects and protects against experimental ischemia/reperfusion (I/R) injury in pulmonary, intestinal, and myocardial tissue. However, its protective abilities against I/R injury in the liver are unknown. We investigated the potential role of GLP-2 pretreatment on hepatic I/R injury in rats. A total of 24 rats were randomly divided into three groups (n = 8). The first group was the control group; the second group was the vehicle-treated hepatic ischemia/reperfusion (HIR, vehicle saline-treated) group; and the third group was the GLP-2 pretreated I/R (GLP2-IR) group. Each rat in the third group was intraperitoneally administered 5 μg GLP-2 for 5 d before the procedure. A portal triad was created to induce ischemia with a vascular atraumatic clamp. After 40 min, the clamp was released to initiate hepatic reperfusion for 6 h. Blood samples and tissue specimens from the liver were obtained. Alanine aminotransferase, aspartate aminotransferase, and total bilirubin levels significantly increased in the saline-treated HIR group (P<0.001), whereas GLP-2 pretreatment significantly decreased their levels (P<0.01). Our data suggested that GLP-2 pretreatment may have a protective effect on liver I/R injury. However, dose-response studies are necessary to determine the most effective dose.

关键词： ischemia/reperfusion liver glucagon-like peptide-2 alanine aminotransferase

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PD-1/PD-L1 blockade in cervical cancer: current studies and perspectives

Yumeng Wang, Guiling Li

《医学前沿（英文）》 2019年第13卷第4期页码 438-450 doi: 10.1007/s11684-018-0674-4

摘要： Cervical cancer (CC) is the fourth most commonly diagnosed female malignancy and a leading cause of cancer-related mortality worldwide, especially in developing countries. Despite the use of advanced screening and preventive vaccines, more than half of all CC cases are diagnosed at advanced stages, when therapeutic options are extremely limited and side effects are severe. Given these circumstances, new and effective treatments are needed. In recent years, exciting progress has been made in immunotherapies, including the rapid development of immune checkpoint inhibitors. Checkpoint blockades targeting the PD-1/PD-L1 axis have achieved effective clinical responses with acceptable toxicity by suppressing tumor progression and improving survival in several tumor types. In this review, we summarize recent advances in our understanding of the PD-1/PD-L1 signaling pathway, including the expression patterns of PD-1/PD-L1 and potential PD-1/PD-L1-related therapeutic strategies for CC.

关键词： PD-1 PD-L1 immune checkpoint blockade antibody immunotherapy cervical cancer

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In memory of Perry L. McCarty, seminal founder of Environmental Biotechnology

《环境科学与工程前沿（英文）》 2023年第17卷第10期 doi: 10.1007/s11783-023-1730-0

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Shear design of high strength concrete prestressed girders

Emad L. LABIB,Hemant B. DHONDE,Thomas T. C. HSU,Y. L. MO

《结构与土木工程前沿（英文）》 2014年第8卷第4期页码 373-387 doi: 10.1007/s11709-014-0087-7

摘要： Normal strength prestressed concrete I-girders are commonly used as the primary superstructure components in highway bridges. However, shear design guidelines for high strength PC girders are not available in the current structural codes. Recently, ten 7.62 m (25 feet) long girders made with high strength concrete were designed, cast, and tested at the University of Houston (UH) to study the ultimate shear strength and the shear concrete contribution ( ) as a function of concrete strength ( ). A simple semi-empirical set of equations was developed based on the test results to predict the ultimate shear strength of prestressed concrete I-girders. The UH-developed set of equations is a function of concrete strength ( ), web area ( ), shear span to effective depth ratio ( / ), and percentage of transverse steel ( ). The proposed UH-Method was found to accurately predict the ultimate shear strength of PC girders with concrete strength up to 117 MPa (17000 psi) ensuring satisfactory ductility. The UH-Method was found to be not as overly conservative as the ACI-318 (2011) code provisions, and also not to overestimate the ultimate shear strength of high strength PC girders as the AASHTO LRFD (2010) code provisions. Moreover, the proposed UH-Method was found fairly accurate and not exceedingly conservative in predicting the concrete contribution to shear for concrete strength up to 117 MPa (17000 psi).

关键词： shear design high strength concrete prestressed girders full-scale tests

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Deeply missing my career idol and role model ― Professor Perry L. McCarty

《环境科学与工程前沿（英文）》 2023年第17卷第9期 doi: 10.1007/s11783-023-1717-x

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Urban watershed management under rapid urbanization

Pengfei DU, Haifeng JIA, Shaw L. YU

《环境科学与工程前沿（英文）》 2012年第6卷第5期页码 595-595 doi: 10.1007/s11783-012-0452-5

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Recombinant aspartate aminotransferase-catalyzed synthesis of L-4-fluorophenylalanine

CHEN Meijuan, JIA Honghua, CHEN Yongsheng, JIANG Min, WEI Ping

《化学科学与工程前沿（英文）》 2008年第2卷第2期页码 220-223 doi: 10.1007/s11705-008-0041-0

摘要： L-4-Fluorophenylalanine (FPhe) was prepared from 4-fluorophenylpyruvate (FPPA) catalyzed by aspartate aminotransferase (Asp-AT) of the recombinant BL21-pET/aspC. After 12 h enzymatic reaction, the FPPA conversion was over 90% and the yield of FPhe could be above 85% under the following optimal conditions: 37°C, pH value range of 5.0–8.0, 5.5 mass ratio of cell to FPPA, 0.6% (w/v) of Tween 80, 7.08 g/L FPPA, and 1.6 of molar ratio of L-Asp to FPPA.

关键词： L-4-Fluorophenylalanine Asp-AT aspartate aminotransferase 4-fluorophenylpyruvate FPPA

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Effects of different doses of cadmium on secondary metabolites and gene expression in Artemisia annua L.

null

《医学前沿（英文）》 2017年第11卷第1期页码 137-146 doi: 10.1007/s11684-016-0486-3

摘要：

This study aims to elucidate the underlying molecular mechanisms of artemisinin accumulation induced by cadmium (Cd). The effects of different Cd concentrations (0, 20, 60, and 120 μmol/L) on the biosynthesis of Artemisia annua L. were examined. Intermediate and end products were quantified by HPLC-ESI-MS/MS analysis. The expression of key biosynthesis enzymes was also determined by qRT-PCR. The results showed that the application of treatment with 60 and 120 μmol/L Cd for 3 days significantly improved the biosynthesis of artemisinic acid, arteannuin B, and artemisinin. The concentrations of artemisinic acid, arteannuin B, and artemisinin in the 120 μmol/L Cd-treated group were 2.26, 102.08, and 33.63 times higher than those in the control group, respectively. The concentrations of arteannuin B and artemisinin in 60 μmol/L Cd-treated leaves were 61.10 and 26.40 times higher than those in the control group, respectively. The relative expression levels of HMGR, FPS, ADS, CYP71AV1, DBR2, ALDH1, and DXR were up-regulated in the 120 μmol/L Cd-treated group because of increased contents of artemisinic metabolites after 3 days of treatment. Hence, appropriate doses of Cd can increase the concentrations of artemisinic metabolites at a certain time point by up-regulating the relative expression levels of key enzyme genes involved in artemisinin biosynthesis.

关键词： Cd secondary metabolites gene expressions Artemisia annua L.

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Reactive extraction for preparation of hydrogen peroxide under pressure

CHENG Yongxi, LI Hongtao, WANG Li, LÜ Shuxiang

《化学科学与工程前沿（英文）》 2008年第2卷第3期页码 335-340 doi: 10.1007/s11705-008-0042-z

摘要： The preparation of hydrogen peroxide from anthrahydroquinone by reactive extraction was investigated. The integration process of oxidation of anthrahydroquinone by air and extraction of hydrogen peroxide from the organic phase with water was carried out in a sieve plate column under pressure. The conversion of anthrahydroquinone increased with increasing pressure resulting in an increase of hydrogen peroxide concentration in the aqueous phase. However, no change in extraction efficiency of hydrogen peroxide was observed. A mathematical model for gas-liquid-liquid reactive extraction was established. In the model, the effects of pressure and gas superficial velocity on reaction were considered. With increasing gas superficial velocity, the conversion of anthrahydroquinone increased, and the fraction of hydrogen peroxide extracted reached a plateau with a maximum of 72.94%. However, both the conversion of anthrahydroquinone and the fraction of hydrogen peroxide extracted decreased with increasing organic phase superficial velocity.

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地下工程的发展提升现代生活质量

Raymond L. Sterling

《工程（英文）》 2017年第3卷第6期页码 780-781 doi: 10.1016/j.eng.2017.12.006

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血清N-聚糖生物标志物诊断ALT水平正常慢性乙型肝炎患者显著肝纤维化和肝硬化的临床意义 Article

王林, 刘艺琪, 顾启馨, 张驰, 徐蕾, 王蕾, 陈翠英, 刘学恩, 赵鸿, 庄辉

《工程（英文）》 2023年第26卷第7期页码 151-158 doi: 10.1016/j.eng.2023.03.008

摘要：

本研究目的是探讨血清N-聚糖模型在285例丙氨酸转移酶（alanine aminotransferase, ALT）水平正常（＜40 U·L^–1）的慢性乙型肝炎（慢性乙肝）患者中诊断显著肝纤维化和肝硬化的临床意义。

关键词：肝纤维化慢性乙型肝炎血清N-聚糖 N-聚糖模型丙氨酸转移酶

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Size-controlled green synthesis of silver nanoparticles assisted by L-cysteine

Wenchao Zhang,Lin Zhang,Yan Sun

《化学科学与工程前沿（英文）》 2015年第9卷第4期页码 494-500 doi: 10.1007/s11705-015-1527-1

摘要： A green and size-controlled synthesis of silver nanoparticles (Ag NPs) in aqueous solution with the assistance of L-cysteine is presented. The size of Ag NPs decreases with the increase of L-cysteine concentration, and thus can be controlled by adjusting L-cysteine concentration. TEM analysis shows that Ag NPs with an average size of 3 nm can be produced in the presence of 1.0 mmol/L L-cysteine, about one sixth of the size of Ag NPs obtained in the absence of L-cysteine (17 nm). The as-synthesized silver colloidal solution is stable and can be stored at room temperature for at least two months without any precipitation. This L-cysteine assisted method is simple, feasible and efficient, and would facilitate the production and application of Ag NPs.

关键词： nanoparticles silver L-cysteine size distribution synthesis

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Quality Function Deployment Implementation in Construction: A Systematic Literature Review

Cudney,William L. Gillis

《工程管理前沿（英文）》 2016年第3卷第3期页码 224-230 doi: 10.15302/J-FEM-2016036

摘要： The construction of new buildings represents a significant investment. The goal of new building construction is to maximize value and minimize cost while staying on time and within budget. Translating customer requirements into engineering terms for new construction design is vital for a construction project to be successful. Quality function deployment has been successfully used in product development to capture the voice of the customer and translate it into engineering characteristics. Quality function deployment then carries these parameters into production and service to ensure the voice of the customer is being met with the final product. The house of quality, a tool within quality function deployment, can provide a means for comparison of owner’s project requirements and the proposed design, along with identifying how the design decisions impact meeting customer requirements and green building requirements. Quality function deployment can effectively link the project phases through design and construction and into operations and maintenance to ensure the owner’s project requirements are met with the final building. This research identifies and categorizes studies of quality function deployment applications in construction. The research method used is a systematic literature review from databases related to quality function deployment in the construction industry published in the periodicals through 2016. The principal findings of implementations, practices, and integrated approaches are then summarized. This article intends to propel further research of quality function deployment in the construction sector.

关键词： construction engineering management quality function deployment systematic review