Research on the Power Sharing Control and Stability of VSGs

Xie, Dong,Zang, Da-Jin,Gao, Peng,Wang, Jun-Jia The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.2

Aiming at the deficiencies of power sharing control performances when a traditional droop control is adopted for microgrid inverters, this paper proposes a microgrid inverter power sharing control strategy based on a virtual synchronous generator. This control method simulates the electromechanical transient characteristics of a synchronous generator in a power system by an ontology algorithm and the control laws of a synchronous generator by control over the speed governor and excitation regulator. As a result, that the microgrid system is able to effectively retain the stability of the voltage and frequency, and the power sharing precision of the microgrid inverter is improved. Based on an analysis of stability of a microgrid system controlled by a virtual synchronous generator, design thoughts are provided for further improvement of the power sharing precision of inverters. The simulation results shows that when the virtual synchronous generator based control strategy was adopted, the power sharing performances of microgrid inverters are improved more obviously than those using the droop control strategy.

Oral delivery of insulin via mesoporous carbon nanoparticles for colonic release allows glycemic control in diabetic rats

Haorong Lin,Jia Zhang,Chaochang Yu,Yan Lu,Jie Ning,Sixian Le,Yue Li,Lin‑quan Zang 한국탄소학회 2019 Carbon Letters Vol.29 No.2

In this article, a new type of mesoporous carbon nanoparticles (MCN) was fabricated as a potential oral delivery system of insulin to reduce the adverse reactions by hypodermic injection. The mesoporous carbon nanoparticles-carried insulin (MCNI) was studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR) compared with the blank MCNs. The Brunauer–Emmett–Teller (BET) method was utilized to calculate the specific surface area. The pore volume and pore size distribution (PSD) curves were calculated by Barrett–Joyner–Halenda (BJH) model. The entrapment efficiency (EE%) and loading content (LC%) of insulin onto the MCNs were determined by RP-HPLC. In vitro insulin release from MCNI was determined in simulated intestinal fluid. To evaluate the pharmacodynamics of MCNIs orally, the variation of glycemia of diabetic rats after oral administration of MCNIs was compared with the rats receiving hypodermic injection of insulin. Besides, the absorption of FITC-labeled MCNs in HCT-116 cells was tested. The results showed that there is significant difference between MCNs and MCNIs through SEM, TEM, and FT-IR. The entrapment efficiency, loading content and in vitro insulin release met the requirements of the pharmacodynamic study. The specific surface area, pore volume and pore size of MCNIs were significantly decreased compared to that of MCNs. The pharmacodynamics study showed that the blood sugar level was significantly decreased after the oral administration of MCNIs. The FITC-labeled MCNs showed significant absorption in HCT-116 cells. The MCNIs were successfully synthesized with commendable entrapment efficiency and loading content which preferably decreased the blood sugar in diabetes rats via oral administration.

Research on the Power Sharing Control and Stability of VSGs

Dong Xie,Da-Jin Zang,Peng Gao,Jun-Jia Wang 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.2

Aiming at the deficiencies of power sharing control performances when a traditional droop control is adopted for microgrid inverters, this paper proposes a microgrid inverter power sharing control strategy based on a virtual synchronous generator. This control method simulates the electromechanical transient characteristics of a synchronous generator in a power system by an ontology algorithm and the control laws of a synchronous generator by control over the speed governor and excitation regulator. As a result, that the microgrid system is able to effectively retain the stability of the voltage and frequency, and the power sharing precision of the microgrid inverter is improved. Based on an analysis of stability of a microgrid system controlled by a virtual synchronous generator, design thoughts are provided for further improvement of the power sharing precision of inverters. The simulation results shows that when the virtual synchronous generator based control strategy was adopted, the power sharing performances of microgrid inverters are improved more obviously than those using the droop control strategy.

The NAD(P)H: Quinine Oxidoreductase 1 (NQO1) Gene 609 C>T Polymorphism is Associated with Gastric Cancer Risk: Evidence from a Case-control Study and a Meta-analysis

Hu, Wei-Guo,Hu, Jia-Jia,Cai, Wei,Zheng, Min-Hua,Zang, Lu,Wang, Zheng-Ting,Zhu, Zheng-Gang Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.5

The association between the NAD(P)H:quinone oxidoreductase 1 (NQO1) gene C609T polymorphism (rs1800566) and gastric cancer has been widely evaluated, but a definitive answer is so far lacking. We first conducted a case-control study to assess this association in a large Han Chinese population, and then performed a meta-analysis to further address this issue. Although our case-control association study indicated no significant difference in the genotype and allele distributions of C609T polymorphism between gastric cancer patients and controls, in the meta analysis involving 4,000 subjects, comparison of alleles 609T and 609C indicated a significantly increased risk (46%) for gastric cancer (95% confidence interval (95%CI) for odds ratio (OR)=1.20-1.79) in individuals with the T allele. The tendency was similar to the homozygote (OR=1.81, 95%CI: 1.16-2.84), dominant models (OR=1.41, 95%CI: 1.12-1.79), as well as recessive model (OR=1.58, 95%CI: 1.06-2.35). Stratified analysis by study design demonstrated stronger associations in population-based than in hospital-based studies. And ethnicity-based analysis demonstrated a significant association in Asians. We conclude that the NQO1 gene C609T polymorphism increases the risk for gastric cancer, especially in Asian populations.

Specific Mutations in APC, with Prognostic Implications in Metastatic Colorectal Cancer

Huan Peng,Jun Ying,Jia Zang,Hao Lu,Xiaokai Zhao,Pengmin Yang,Xintao Wang,Jieyi Li,Ziying Gong,Daoyun Zhang,Zhiguo Wang 대한암학회 2023 Cancer Research and Treatment Vol.55 No.4

Purpose Loss-of-function mutations in the adenomatous polyposis coli (APC) gene are common in metastatic colorectal cancer (mCRC). However, the characteristic of APC specific mutations in mCRC is poorly understood. Here, we explored the clinical and molecular characteristics of N-terminal and C-terminal side APC mutations in Chinese patients with mCRC. Materials and Methods Hybrid capture-based next-generation sequencing was performed on tumor tissues from 275 mCRC pati-ents to detect mutations in 639 tumor-associated genes. The prognostic value and gene-pathway difference between APC specific mutations in mCRC patients were analyzed. Results APC mutations were highly clustered, accounting for 73% of all mCRC patients, and most of them were truncating mutations. The tumor mutation burden of the N-terminal side APC mutations group (n=76) was significantly lower than that of the C-terminal side group (n=123) (p < 0.001), further confirmed by the public database. Survival analysis showed that mCRC patients with N-terminus side APC mutations had longer overall survival than C-terminus side. Tumor gene pathway analysis showed that gene mutations in the RTK/RAS, Wnt and transforming growth factor β signaling pathways of the C-terminal group were significantly higher than those of the N-terminal group (p < 0.05). Additionally, KRAS, AMER1, TGFBR2, and ARID1A driver mutations were more common in patients with C-terminal side APC mutations. Conclusion APC specific mutations have potential function as mCRC prognostic biomarkers. There are obvious differences in the gene mutation patterns between the C-terminus and N-terminus APC mutations group, which may have certain guiding significance for the subsequent precise treatment of mCRC.

Research on a Model of Extracting Persons` Information Based on Statistic Method and Conceptual Knowledge

( Xiang Feng Wei ),( Ning Jia ),( Quan Zhang ),( Han Fen Zang ) 한국언어정보학회 2007 학술대회 논문집 Vol.2007 No.-

In order to extract some important information of a person from text, an extracting model was proposed. The person``s name is recognized based on the maximal entropy statistic model and the training corpus. The sentences surrounding the person``s name are analyzed according to the conceptual knowledge base. The three main elements of events, domain, situation and background, are also extracted from the sentences to construct the structure of events about the person.

The Stabilization and 3D Visual Simulation of the Triple Inverted Pendulum based on CGA-PIDNN

Xiu-Ling Zhang,Hong-Min Fan,Jia-Yin Zang,Liang Zhao,Shuang Hao 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.4

Aiming at the triple inverted pendulum which is a strong coupling, multivariable, high-order and unsteady system, a design method of the controller based on PID neural network (PIDNN) optimized by cloud genetic algorithm (CGA) is proposed, this method is called CGA-PIDNN. CGA can be applied to learn and train the PIDNN connection weights. CGA can overcome the defect of the slow convergence rate and premature convergence for genetic algorithm (GA). PIDNN is a simple and normative network which is easy to be realized and has a good dynamic performance. The CGA-PIDNN control system of triple inverted pendulum is verified with MATLAB simulation test. The comparison results with the control effect of PIDNN control system optimized by standard GA (GA-PIDNN) are presented first. Then in LabVIEW environment, by using the combination of virtual reality technology and MATLAB, the three-dimensional (3D) animation simulation model of the triple inverted pendulum CGA-PIDNN control system is built. The simulation results indicate that CGA-PIDNN control method is effective, whose control effects are superior to those by GA-PIDNN control, it is believed that CGAPIDNN is effective and will become a promising candidate of control methods.

Improved Temperature Characteristics of an Aspergillus oryzae GHF11 Xylanase, by In Silico Design and Site-directed Mutagenesis

Die Hu,Jianfang Li,Qin Wu,Jia Zang,Jianqing Cheng,Minchen Wu 한국생물공학회 2016 Biotechnology and Bioprocess Engineering Vol.21 No.6

To improve the temperature characteristics of a mesophilic glycoside hydrolase family (GHF) 11 xylanase AoXyn11A from Aspergillus oryzae, both introduction of a disulfide bridge and the substitution of a specific amino acid were carried out by in silico design and site-directed mutagenesis. Based on the analysis of a known crystal structure of thermophilic xylanase TlXynA from Thermomyces lanuginosus, and the alignment of primary structures between AoXyn11A and TlXynA, one mutant AoXyn11AM with a disulfide bridge (Cys108–Cys152) was designed by replacing the Ser108 and Asn152 of AoXyn11A with Cys residues, respectively. Additionally, based on the analysis of amino acid B-factor values, another mutant AoXyn11AM-G22A was predicted by substituting Gly22 of AoXyn11AM (having the maximum B-factor value of 69.25 Å, with the corresponding Ala23 of TlXynA. Thereafter, two mutant xylanase-encoding genes, Aoxyn11AM and Aoxyn11AM-G22A, were constructed by site-directed mutagenesis. Aoxyn11A and two mutant genes were expressed in E. coli BL21(DE3) respectively, and three expressed recombinant xylanases, reAoXyn11A, reAoXyn11AM and reAoXyn11AM-G22A, were purified to homogeneity. The temperature optima of reAoXyn11AM and reAoXyn11AM-G22A were 60 and 65°C, respectively, being 5 and 10°C higher than that of reAoXyn11A. Their thermal inactivation half-lives at 50°C were 1.8- and 8.4-folds longer than that of reAoXyn11A. There were no obvious alterations after mutations in specific activity and enzymatic properties, except for the temperature characteristics.

RhGLP-1 (7-36) protects diabetic rats against cerebral ischemia-reperfusion injury via up-regulating expression of Nrf2/HO-1 and increasing the activities of SOD

Fang, Yi,Liu, Xiaofang,Zhao, Libo,Wei, Zhongna,Jiang, Daoli,Shao, Hua,Zang, Yannan,Xu, Jia,Wang, Qian,Liu, Yang,Peng, Ye,Yin, Xiaoxing The Korean Society of Pharmacology 2017 The Korean Journal of Physiology & Pharmacology Vol.21 No.5

The present study aimed to explore the neuroprotective effect and possible mechanisms of rhGLP-1 (7-36) against transient ischemia/reperfusion injuries induced by middle cerebral artery occlusion (MCAO) in type 2 diabetic rats. First, diabetic rats were established by a combination of a high-fat diet and low-dose streptozotocin (STZ) (30 mg/kg, intraperitoneally). Second, they were subjected to MCAO for 2 h, then treated with rhGLP-1 (7-36) (10, 20, $40{\mu}g/kg$ i.p.) at the same time of reperfusion. In the following 3 days, they were injected with rhGLP-1 (7-36) at the same dose and route for three times each day. After 72 h, hypoglycemic effects were assessed by blood glucose changes, and neuroprotective effects were evaluated by neurological deficits, infarct volume and histomorphology. Mechanisms were investigated by detecting the distribution and expression of the nuclear factor erythroid-derived factor 2 related factor 2 (Nrf2) in ischemic brain tissue, the levels of phospho-PI3 kinase (PI3K)/PI3K ratio and heme-oxygenase-1 (HO-l), as well as the activities of superoxide dismutase (SOD) and the contents of malondialdehyde (MDA). Our results showed that rhGLP-1 (7-36) significantly reduced blood glucose and infarction volume, alleviated neurological deficits, enhanced the density of surviving neurons and vascular proliferation. The nuclear positive cells ratio and expression of Nrf2, the levels of P-PI3K/PI3K ratio and HO-l increased, the activities of SOD increased and the contents of MDA decreased. The current results indicated the protective effect of rhGLP-1 (7-36) in diabetic rats following MCAO/R that may be concerned with reducing blood glucose, up-regulating expression of Nrf2/HO-1 and increasing the activities of SOD.

RhGLP-1 (7-36) protects diabetic rats against cerebral ischemia-reperfusion injury via up-regulating expression of Nrf2/HO-1 and increasing the activities of SOD

Yi Fang,Xiaofang Liu,Libo Zhao,Zhongna Wei,Daoli Jiang,Hua Shao,Yannan Zang,Jia Xu,Qian Wang,Yang Liu,Ye Peng,Xiaoxing Yin 대한약리학회 2017 The Korean Journal of Physiology & Pharmacology Vol.21 No.5

The present study aimed to explore the neuroprotective effect and possible mechanisms of rhGLP-1 (7-36) against transient ischemia/reperfusion injuries induced by middle cerebral artery occlusion (MCAO) in type 2 diabetic rats. First, diabetic rats were established by a combination of a high-fat diet and low-dose streptozotocin (STZ) (30 mg/kg, intraperitoneally). Second, they were subjected to MCAO for 2 h, then treated with rhGLP-1 (7-36) (10, 20, 40 μg/kg i.p.) at the same time of reperfusion. In the following 3 days, they were injected with rhGLP-1 (7- 36) at the same dose and route for three times each day. After 72 h, hypoglycemic effects were assessed by blood glucose changes, and neuroprotective effects were evaluated by neurological deficits, infarct volume and histomorphology. Mechanisms were investigated by detecting the distribution and expression of the nuclear factor erythroid-derived factor 2 related factor 2 (Nrf2) in ischemic brain tissue, the levels of phospho-PI3 kinase (PI3K)/PI3K ratio and heme-oxygenase-1 (HO-l), as well as the activities of superoxide dismutase (SOD) and the contents of malondialdehyde (MDA). Our results showed that rhGLP-1 (7-36) significantly reduced blood glucose and infarction volume, alleviated neurological deficits, enhanced the density of surviving neurons and vascular proliferation. The nuclear positive cells ratio and expression of Nrf2, the levels of P-PI3K/PI3K ratio and HO-l increased, the activities of SOD increased and the contents of MDA decreased. The current results indicated the protective effect of rhGLP-1 (7-36) in diabetic rats following MCAO/R that may be concerned with reducing blood glucose, up-regulating expression of Nrf2/HO-1 and increasing the activities of SOD.