Beijing Wuzi University

About: Beijing Wuzi University is a education organization based out in Beijing, China. It is known for research contribution in the topics: Supply chain & Computer science. The organization has 1210 authors who have published 1092 publications receiving 6370 citations.

Overexpression of Escherichia coli Acetyl Esterase Using a Strategy of Multi-copy Promoters

Abstract: Acetyl esterase (AE) plays an important role in bioconversion of lignocellulosic biomass. However, the expression level of AE from wild type strains is relatively low. The aim of the study was to enhance the activity of AE using the strategy of multi-copy promoters. A commercial strain E. coli JM110 was used as the host of expression plasmid. pKK223-3-ybaC (pK-ybaC) is a recombinant plasmid, and it carries ybaC gene (encoding AE) that was derived from E. coli RB3. E. coli JM110 (pK-ybaC; EcKy) was a recombinant strain that contains pK-ybaC. Fragment P3 that contains three copies of the core-tac-promoter and fragment P5 that contains five copies of the core-tac-promoter were synthesized. Plasmid pK-ybaC was extracted from EcKy and was linearized by EcoR I and BamH I to remove its wild promoter. Then fragment P3 was subcloned into linearized pK-ybaC to generate pKTH-ybaC and fragment P5 was inserted into pK-ybaC to generate pKFI-ybaC. In-Fusion kit (Takara) was used to construct recombinant plasmids according to the instruction of the manufacturer. The two plasmids were then transformed into E. coli JM110 to get the recombinant strain E. coli JM110 (pKTH-ybaC; EcTH) and E. coli JM110 (pKFI-ybaC; EcFI). The highest activity of AE from EcTH was 3.04 U mL−1. It was 7.8 times of that from the parental strain E. coli RB3. The peak value of AE activity from EcFI was 35.66 U mL−1, which was 91.4 times of that from E. coli RB3. EcFI showed the highest transcription level of ybaC gene, and its value was 4239 times of that in E. coli RB3. The K m value was 3.49 mmol L−1 and the V max value was 43.29 µmol s−1 mg−1 for AE from EcFI. The K cat/K m value was around fivefold of that from the parental strain E.coli RB3. Two engineered bacterial strains that contain three copies and five copies of the core-tac-promoter were constructed. The activity of AE from the two engineered strains was enhanced significantly compared to that from the parental strain. The results indicated the feasibility of enhancing AE activity using the strategy of multi-copy promoters.

Research on Order Batching Problem of Intelligent Warehouse Picking System

Abstract: Because of its high efficiency and flexibility, the intelligent warehousing picking system has gradually become the development trend of order picking system of the e-commerce logistics distribution center. The intelligent warehousing picking system is a kind of “parts-to-picker” operation mode, in which the logistics robot carries the shelf to the designated picking station for picking operation. In order to improve the efficiency of order picking, this paper studies the order batching problem under this new picking mode, establishes a mathematical model, and proposes an improved dynamic clustering algorithm.

ICT Competency Framework and Training Strategies

Abstract: This paper intends to construct a competency framework for bilingual teachers in universities of China on the review of literature on this topic home and abroad. The author mentions the necessity of setting up an ICT competency standard and proposes an ICT competency framework for bilingual teachers; according to the status quo of teachers using ICT in teaching, suggestions are put forward on teacher training.

Complexity Analysis and Parameter Estimation of Dynamic Metabolic Systems

Abstract: A metabolic system consists of a number of reactions transforming molecules of one kind into another to provide the energy that living cells need. Based on the biochemical reaction principles, dynamic metabolic systems can be modeled by a group of coupled differential equations which consists of parameters, states (concentration of molecules involved), and reaction rates. Reaction rates are typically either polynomials or rational functions in states and constant parameters. As a result, dynamic metabolic systems are a group of differential equations nonlinear and coupled in both parameters and states. Therefore, it is challenging to estimate parameters in complex dynamic metabolic systems. In this paper, we propose a method to analyze the complexity of dynamic metabolic systems for parameter estimation. As a result, the estimation of parameters in dynamic metabolic systems is reduced to the estimation of parameters in a group of decoupled rational functions plus polynomials (which we call improper rational functions) or in polynomials. Furthermore, by taking its special structure of improper rational functions, we develop an efficient algorithm to estimate parameters in improper rational functions. The proposed method is applied to the estimation of parameters in a dynamic metabolic system. The simulation results show the superior performance of the proposed method.

A principal-agent model on retailer's order contract in perishable product supply chain

Abstract: In this paper, we set up a principal-agent model of perishable product supply chain under centralized decision making situation and decentralized situation with information symmetric and information asymmetric respectively we find that supplier can coordinate the supply chain through proper strategy. Especially under information asymmetric condition, difference basic order and different kickback coefficient between high quality and low quality distributors can induce a better output, thus the supply chain system's profit can be optimized. Every paper should include an abstract with 100–300 words. At the end of the abstract, skip a line and then type