On-line Specific Growth Rate Control for Improving Reduced Glutathione Production in Saccharomyces cerevisiae

Zhi-Qiang Xiong,Mei-jin Guo,Ju Chu,Ying-ping Zhuang,Siliang Zhang 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.5

Reduced glutathione (GSH), the abundant bioactive tripeptide in most living cells, is widely used in pharmaceutical, food, and cosmetic industries. Specific growth rate (μ) is a key physiological parameter for GSH high-cell-density cultivation using microbial cell factories. Here, based on a biomass probe, an on-line μ feedback control was developed to regulate glucose feeding rate during the fed-batch phase for overproducing GSH in Saccharomyces cerevisiae. Compared with real-time μ controlled at 0.15/h, μ controlled at 0.2/h achieved yeast dry weight (120 g/L), GSH concentration (1.5 g/L), and intracellular GSH content (1.25%), which improved by 9, 150, and 129.1%, respectively. To our knowledge, this is the first report about on-line μ feedback control for GSH production. On-line μ control led to 59.38 mg/L/h of GSH productivity and 3.52 mg/g of GSH yield on glucose, which improved by 107.6 and 7.2%, respectively, in comparison with those of traditional ethanol feedback control (maintaining ethanol concentration at 1%). Taken together, the on-line μ feedback control is a promising method as an efficient alternative to conventional feed control techniques presently practiced in the GSH industry, and has the potential for the production of other valuable chemicals.

A Power and Performance Management Simulation Platform for Web Application Server Cluster

Zhi Xiong,Zhongliang Xue,Weihong Cai,Lingru Cai,Juan Yang 보안공학연구지원센터 2016 International Journal of Future Generation Communi Vol.9 No.12

Web application server cluster has been widely used to improve the performance of web application servers. Because web load is highly variable, we need to dynamically manage cluster’s deployment so as to reduce power consumption and meanwhile satisfy load performance demand. To facilitate researchers to evaluate a management strategy or choose key parameters for it, we propose a CloudSim-based simulation platform in this paper. It can simulate different cluster deployment algorithm, request scheduling algorithm and load feature, where cluster’s deployment includes the on/off state, CPU frequency and request scheduling parameter(s) of each server. By the aid of HookTimer component, the platform supports periodical and conditional deployment trigger modes, and can calculate some common performance indicators. The usage of interface, dynamic proxy technique and XML configuration file make the platform have good extensibility and configurability. In addition, a request-number-triggered management strategy is proposed and simulated by the platform. The simulation results demonstrate the feasibility of the platform.

Suboptimal Relational Tree Configuration and Robust Control Based on the Leader-follower Model for Self-organizing Systems Without GPS Support

Zhi-gang Xiong,Ya-Song Luo,Zhong Liu,Zhi-kun Liu 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.4

This paper surveys the formation acquisition and maintenance of multi-agent systems, while the communication graph is obtained without human designations. Given that all agents move along unpredictable paths during formation acquisition, the systems adopt the leader-follower model. For better expression of the graph construction, a relational tree is introduced to describe the follower-leader pairs. Then, a distributed method is proposed for suboptimal relational tree configuration. By utilizing particle swarm optimization (PSO), the search for follower-leader pairs is converted to permutation optimization. Based on principal component analysis (PCA), the entire group is divided into several small groups, and the optimization can be implemented in each group, thus releasing the computation burden. To acquire the formation defined by the suboptimal relational tree, a second nonlinear controller subject to the loss of GPS information is established. The controller takes the reference in the local velocity frame as inputs, and proportional and differential components are introduced to provide a soft control. In addition, adaptive parameters are designed for robust control. By tuning the parameters autonomously, self-organized systems can work well in various scenarios even without manual adjustment of parameters. Mathematical and numerical analyses are conducted to prove the feasibility of the proposed strategy.

Interleukin-4 and -8 Gene Polymorphisms and Risk of Gastric Cancer in a Population in Southwestern China

Pan, Xiong-Fei,Wen, Ying,Loh, Marie,Wen, Yuan-Yuan,Yang, Shu-Juan,Zhao, Zhi-Mei,Tian, Zhi,Huang, He,Lan, Hui,Chen, Feng,Soong, Richie,Yang, Chun-Xia Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.7

Background: Gastric carcinogenesis is a complicated process that involves environmental and genetic factors like interleukin-4 (IL-4) and IL-8. Single nucleotide polymorphisms in their genes are associated with changed levels of gene expression. Here, we investigated the association between IL4-590 C>T and IL8-251T>A and gastric cancer (GC) risk in Sichuan of Southwestern China. Materials and Methods: We surveyed the research subjects using a self-designed questionnaire with questions on demographic factors and putative risk factors. Approximately 2-5ml of whole blood was collected after field survey to analyze IL4-590 C>T and IL8-251T>A genotypes using MALDI-TOF MS. Results: Our study recruited 308 pairs of GC patients and controls, including 224 (72.7%) men and 84 (27.3%) women in each group. There were 99 cardia and 176 noncardia GC patients in the case group. The case and control groups had an average age of $57.7{\pm}10.6$ ($mean{\pm}SD$) and $57.6{\pm}11.1$ years. GC patients reported a significantly greater proportion of family history of cancer (29.9% vs 10.7%, p<0.01) and drinking (54.6% vs 43.2%, p<0.01) than did controls. Variant genotypes of IL-4-590 C>T and IL-8-251 T>A were not associated with overall GC risk (adjusted OR, 0.89; 95%CI, 0.61-1.28 for CT or CC vs TT; adjusted OR, 1.14; 95%CI, 0.86-1.79 for TA or AA vs TT). Stratification analysis of two SNPs for risk by subsites only found that variant IL-8-251 TA or AA genotype was associated with increased noncardia GC risk (adjusted OR, 2.58; 95%CI, 1.19-5.57). We did not observe interactions between the IL-8-251 T>A genotype and smoking (adjusted OR, 0.38; 95%CI, 0.08-1.79) or drinking (adjusted OR, 0.36; 95%CI, 0.08-1.65) for risk of noncardia GC. Conclusions: Our data indicate no association between the two SNPs of IL-4-590 and IL-8-251 with overall GC risk, while the IL-8-251 TA or AA genotype conferred risk of cardia GC. Our findings contribute to the evidence body for risk of SNPs associated with the development of gastric cancer in this region.

试论韩国奎章阁本《文选 · 魏都赋》注者题录的有关问题

熊良智(liang?zhi Xiong) 國際言語文學會 2007 國際言語文學 Vol.- No.15

ON THREE SPECTRAL REGULARIZATION METHODS FOR A BACKWARD HEAT CONDUCTION PROBLEM

Xiong, Xiang-Tuan,Fu, Chu-Li,Qian, Zhi Korean Mathematical Society 2007 대한수학회지 Vol.44 No.6

We introduce three spectral regularization methods for solving a backward heat conduction problem (BHCP). For the three spectral regularization methods, we give the stability error estimates with optimal order under an a-priori and an a-posteriori regularization parameter choice rule. Numerical results show that our theoretical results are effective.

IL-12 Regulates B7-H1 Expression in Ovarian Cancer-associated Macrophages by Effects on NF-κB Signalling

Xiong, Hai-Yu,Ma, Ting-Ting,Wu, Bi-Tao,Lin, Yan,Tu, Zhi-Guang Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.14

Background and Aim: B7-H1, a co-inhibitory molecule of the B7 family, is found aberrantly expressed in ovarian cancer cells and infiltrating macrophage/dendritic-like cells, and plays a critical role in immune evasion by ovarian cancer. IL-12, an inducer of Th1 cell development, exerts immunomodulatory effects on ovarian cancer. However, whether IL-12 regulates B7-H1 expression in human ovarian cancer associated-macrophages has not been clarified. Therefore, we investigated the effects of IL-12 on the expression of B7-H1 in ovarian cancer-associated macrophages and possible mechanisms. Methods: PMA induced THP-1-derived macrophages or human monocyte-derived macrophages were treated with recombinant IL-12 (rIL-12) or infected with adenovirus carrying human IL-12 gene (Ad-IL-12-GFP) for 24 h, then cocultured with the SKOV3 ovarian cancer cell line for another 24 h. Macrophages were collected for real-time PCR and Western blot to detect the expression of B7-H1, and activation of the NF-${\kappa}B$ signaling pathway. Moreover, supernatants were collected to assay for IL-12, IFN-${\gamma}$ and IL-10 by ELISA. In addition, monocyte-derived macrophages treated with IFN-${\gamma}$ were cocultured with SKOV3 and determined for the expression of B7-H1. Furthermore, the expression of B7-H1 in monocyte-derived macrophages was also evaluated after blocking NF-${\kappa}B$ signaling. Results: The expression of B7-H1 was significantly upregulated in monocyte-derived macrophages treated with rIL-12 or Ad-IL-12-GFP compared with the control groups (p<0.05), accompanied by a remarkable upregulation of IFN-${\gamma}$ (p<0.05), a marked downregulation of IL-10 (p<0.05) and activation of NF-${\kappa}B$ signaling. However, the upregulation of B7-H1 was inhibited by blocking the NF-${\kappa}B$ signaling pathway (p<0.05). Expression of B7-H1 was also increased (p<0.05) in monocyte-derived macrophages treated with IFN-${\gamma}$ and cocultured with SKOV3. By contrast, the expression of B7-H1 in THP-1-derived macrophages was significantly decreased when treated in the same way as monocyte-derived macrophages (p<0.05), and IL-10 was also significantly decreased but IFN-${\gamma}$ was almost absent. Conclusions: IL-12 upregulates the expression of B7-H1 in monocyte-derived macrophages, which is possible though inducing the secretion of IFN-${\gamma}$ and further activating the NF-${\kappa}B$ signal pathway. However, IL-12 downregulates the expression of B7-H1 in THP-1-derived macrophages, associated with a lack of IFN-${\gamma}$ and inhibition of expression of IL-10.

Interleukin-10 Gene Promoter Polymorphisms and Risk of Gastric Cancer in a Chinese Population: Single Nucleotide and Haplotype Analyses

Pan, Xiong-Fei,Yang, Shu-Juan,Loh, Marie,Xie, Yao,Wen, Yuan-Yuan,Tian, Zhi,Huang, He,Lan, Hui,Chen, Feng,Soong, Richie,Yang, Chun-Xia Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.4

Objectives: Interleukin (IL) -10 is a potent cytokine with a dual ability to immunosuppress or immunostimulate. We aimed to explore the association of IL10 promoter polymorphisms with risk of gastric cancer (GC) in a Han population in Southwestern China. Methods: We enrolled 308 pairs of GC and control subjects from four hospitals and a community between October 2010 and August 2011 in a 1:1 matched case-control design. Demographic information was collected using a designed questionnaire. IL10-592 A>C and IL10-1082 A>G polymorphisms were determined by Sequenom MassARRAY analysis. Results: Patients with GC reported statistically higher proportions of family history of cancer (29.9% versus 10.7%, P<0.01) and alcohol drinking (54.6% versus 43.2%, P<0.01) than did controls. Similar results were observed in comparison between non-cardia GC patients and controls (P<0.01 and P=0.03). Variant genotypes of IL10-592 A>C and IL10-1082 A>G were not associated with overall GC risk (adjusted OR, 0.94, 95% CI, 0.66-1.33; adjusted OR, 1.00, 95% CI, 0.62-1.60). Sub-analysis showed that the IL10-592 AC/CC variant genotype was associated with decreased non-cardia GC risk (adjusted OR, 0.58; 95% CI, 0.36-0.95). No association was found between any of the IL10 haplotypes established from two polymorphisms and risk of non-cardia GC. Conclusions: In conclusion, our data do not link the two SNPs of IL10-592 and IL10-1082 with overall GC risk. We demonstrate that IL10-592 polymorphism is associated with protective effect against non-cardia GC. Our findings may offer insight into risk associated with the development of GC in this region.

Experimental Study on Shear Transfer Performance of Uncracked Monolithic Steel Fiber Concrete

Qing Zhi,Jingang Xiong,Wenjie Yang,Sha Liu 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.12

Shear transfer performance at interface of steel fiber reinforced concrete (SFRC) is of great importance that many factors influence the shear transfer performance of SFRC such as concrete strength and aggregate interlock, reinforcement dowel action and steel fiber. Many studies have focused on part of the factors. The shear transfer performance of uncracked monolithic SFRC is studied in this paper by considering the combined effects of cohesion, clamping stress, confined stress, reinforcement, and steel fiber. Thus, this study presents a series of direct shear tests by Z-type push-off specimens. The direct shear strength, failure mode and failure process of plain SFRC and reinforced SFRC are studied, and their shear stress-slip and shear stress-crack width responses of the tested specimens are obtained. Test results showed that reinforcement and steel fibers can improve the ductile behavior and shear strength of the shear interface simultaneously. And shear stress-slip and –crack curves of the test specimens with those combined effects are strongly nonlinear. Finally, based on the existing shear strength calculation model and the test results of this paper, a shear transfer calculation formula of SFRC interface is proposed and verified according to the Mohr Coulomb failure criteria.

Experimental Study of the Shear Capacity of Steel Beam-to-L-CFST Column Connections

Qingqing Xiong,Wang Zhang,Zhi-Hua Chen,Yansheng Du,Ting Zhou 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.3

This paper aims to investigate the shear performance of a new and innovative type of vertical stiff ener connection between steel beams and L-shaped columns composed of concrete-fi lled steel tubes connected by transverse and vertical steel plates (L-CFST columns) in high-rise residential buildings. Quasi-static cyclic loading tests were performed on fi ve full-scale specimens to investigate the panel zone behaviours. Based on the experimental results, the hysteretic responses, skeleton curves of the shear force–deformation, ductility, stiff ness degradation, energy dissipation and strain are discussed. The variables studied in these experiments include the joint type, axial compression ratio, cross-sectional area and width-to-thickness ratio of the vertical stiff ener, and presence of concrete. The results indicate that the cross-sectional area of the vertical stiff eners plays a critical role in the performance of the panel zone. Two types of failure modes were observed outside the panel zone: fracturing of the vertical stiff eners and fracturing of the beam fl ange connecting plate. Shear deformation of the panel zone was obvious in the exterior joint specimens, and the corresponding maximum shear deformation reached 0.05 rad. Furthermore, the scopes of the panel zone in the corner and exterior joint specimens were determined by the strain distribution.