Hypoglycemic effect of Gynostemma pentaphyllum saponins by enhancing the Nrf2 signaling pathway in STZ-inducing diabetic rats

Dawei Gao,Min Zhao,Ximing Qi,Yanping Liu,Nan Li,Zhiwei Liu,Yanhong Bian 대한약학회 2016 Archives of Pharmacal Research Vol.39 No.2

Gynostemma pentaphyllum (GP) is a natural plant resources for diabetes therapy, however, there is little research on the mechanisms of GP. The present study was undertaken to characterize if G. pentaphyllum saponins (GPs) is the principal active compound of GP responsible for anti-diabetes, and to examine the relativity between blood glucose modulate and antioxidation. The GPs-treated streptozotocin diabetic rats had a more effective hypoglycemic status than those of diabetic control rats, which also ameliorate dyslipidemia. GPs has increased SOD and GSH-px activities, and the spleen and thymus indexes in diabetic rats. The insulin levels in the GPs-treated groups were significantly higher than diabetic control group. Our finding provides a new insight into the application of GPs for the treatment of oxidative stress related diseases.

TGF-β promotes pericyte-myofibroblast transition in subretinal fibrosis through the Smad2/3 and Akt/mTOR pathways

Zhao Zhenzhen,Zhang Yumeng,Zhang Chaoyang,Zhang Jingting,Luo Xueting,Qiu Qinghua,Luo Dawei,Zhang Jingfa 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Subretinal fibrosis remains a major obstacle to the management of neovascular age-related macular degeneration. Choroidal pericytes were found to be a significant source of subretinal fibrosis, but the underlying mechanisms of pericyte-myofibroblast transition (PMT) remain largely unknown. The goal of this study was to explore the role and potential mechanisms by which PMT contributes to subretinal fibrosis. Choroidal neovascularization (CNV) was induced by laser photocoagulation in transgenic mice with the collagen1α1-green fluorescent protein (Col1α1-GFP) reporter, and recombinant adeno-associated virus 2 (rAAV2)-mediated TGF-β2 (rAAV2-TGF-β2) was administered intravitreally to further induce PMT. Primary mouse choroidal GFP-positive pericytes were treated with TGF-β2 in combination with siRNAs targeting Smad2/3, the Akt inhibitor MK2206 or the mTOR inhibitor rapamycin to examine cell proliferation, migration, and differentiation into myofibroblasts. The involvement of the Akt/mTOR pathway in PMT in subretinal fibrosis was further investigated in vivo. Intraocular TGF-β2 overexpression induced GFP-positive pericyte infiltration and PMT in subretinal fibrosis, which was mimicked in vitro. Knockdown of Smad2/3 or inhibition of Akt/mTOR decreased cell proliferation, PMT and migration in primary mouse pericytes. Combined inhibition of Smad2/3 and mTOR showed synergistic effects on attenuating α-smooth muscle actin (α-SMA) expression and cell proliferation. In mice with laser-induced CNV, the administration of the Akt/mTOR inhibitors suppressed pericyte proliferation and alleviated the severity of subretinal fibrosis. Our results showed that PMT plays a pivotal role in subretinal fibrosis, which was induced by TGF-β2 through the Smad2/3 and Akt/mTOR pathways. Thus, inhibiting PMT may be a novel strategy for the treatment of subretinal fibrosis.

Targeted Editing of Myostatin Gene in Sheep by Transcription Activator-like Effector Nucleases

Zhao, Xinxia,Ni, Wei,Chen, Chuangfu,Sai, Wujiafu,Qiao, Jun,Sheng, Jingliang,Zhang, Hui,Li, Guozhong,Wang, Dawei,Hu, Shengwei Asian Australasian Association of Animal Productio 2016 Animal Bioscience Vol.29 No.3

Myostatin (MSTN) is a secreted growth factor expressed in skeletal muscle and adipose tissue that negatively regulates skeletal muscle mass. Gene knockout of MSTN can result in increasing muscle mass in sheep. The objectives were to investigate whether myostatin gene can be edited in sheep by transcription activator-like effector nucleases (TALENs) in tandem with single-stranded DNA oligonucleotides (ssODNs). We designed a pair of TALENs to target a highly conserved sequence in the coding region of the sheep MSTN gene. The activity of the TALENs was verified by using luciferase single-strand annealing reporter assay in HEK 293T cell line. Co-transfection of TALENs and ssODNs oligonucleotides induced precise gene editing of myostatin gene in sheep primary fibroblasts. MSTN gene-edited cells were successfully used as nuclear donors for generating cloned embryos. TALENs combined with ssDNA oligonucleotides provide a useful approach for precise gene modification in livestock animals.

A novel method for longitudinal modification and tooth contact analysis of non-circular cylindrical gears

Dawei Li,Yongping Liu,Jun Gong,Yongqiao Wei,Gang Zhao 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.12

The traditional geometry of non-circular cylindrical gears provides a contact line between tooth surfaces. In a misaligned non-circular cylindrical gear drive, causing edge contacts that result in noise and vibration. The point contact of the tooth surface is achieved by modification of the driving gear in the longitudinal direction, in order to reduce the sensitivity of tooth surface contact to installation errors. The proposed longitudinal modification method is based on the application of a grinding worm by controlling the center distance of non-circular cylindrical gear and worm. Based on the gear meshing principle, a mathematical model of the tooth surfaces of non-circular cylindrical gears is established, and a parametric tooth surface equation with a unified expression is obtained. Tooth contact analysis (TCA) of non-circular cylindrical gears shows that the contact path and contact area on the tooth surface are shifted with the change of installation error, but still distributed in the middle of the tooth surface without creating edge contact. The transmission error is increased with the growth of installation error. Tooth modification in a longitudinal direction has an obvious improvement effect on the bad tooth contact condition, but too large a tooth modification parameter will make the tooth surface load distribution concentrated in a smaller area, which results in the decrease of gear load capacity.

New dammarane-type triterpenoids from the leaves of Panax notoginseng and their protein tyrosine phosphatase 1B inhibitory activity

Dawei Li,Jiaqing Cao,Xiuli Bi,Xichun Xia,Wei Li,Yuqing Zhao 고려인삼학회 2014 Journal of Ginseng Research Vol.38 No.1

Background: Panax notoginseng has been used as a general tonic agent to invigorate human body for millennia in China and continued to be used until present. Methods: Some chromatographic methods were performed to isolate pure triterpenoids, and their structures were determined by nuclear magnetic resonance (NMR) experiments. Anti-diabetes activities of isolated compounds were evaluated through their inhibitory activity of protein tyrosine phosphatase 1B (PTP1B) enzyme. Results and Conclusion: Three new dammarane-type triterpenoids, notoginsenoside-LX (1), notoginsenoside-LY (2), and notoginsenoside-FZ (3) together with eighteen known compounds were isolated from the Panax notoginseng leaves. The structure-activity relationship of the compounds with dammaranetype triterpenoids and their PTP1B inhibitory activity were also reported. Results showed that compounds 2, 15, 20, and 21 can significantly inhibit the enzyme activity of PTP1B in a dose-dependent manner, with inhibitory concentration 50 (IC50) values of 29.08 mM, 21.27 μM, 28.12 μM, and 26.59 μM, respectively. The results suggested that Panax notoginseng leaves might have potential as a new therapeutic agent for the treatment of diabetes.

New dammarane-type triterpenoids from the leaves of Panax notoginseng and their protein tyrosine phosphatase 1B inhibitory activity

Li, Dawei,Cao, Jiaqing,Bi, Xiuli,Xia, Xichun,Li, Wei,Zhao, Yuqing The Korean Society of Ginseng 2014 Journal of Ginseng Research Vol.38 No.1

Background: Panax notoginseng has been used as a general tonic agent to invigorate human body for millennia in China and continued to be used until present. Methods: Some chromatographic methods were performed to isolate pure triterpenoids, and their structures were determined by nuclear magnetic resonance (NMR) experiments. Anti-diabetes activities of isolated compounds were evaluated through their inhibitory activity of protein tyrosine phosphatase 1B (PTP1B) enzyme. Results and Conclusion: Three new dammarane-type triterpenoids, notoginsenoside-LX (1), notoginsenoside-LY (2), and notoginsenoside-FZ (3) together with eighteen known compounds were isolated from the Panax notoginseng leaves. The structure-activity relationship of the compounds with dammaranetype triterpenoids and their PTP1B inhibitory activity were also reported. Results showed that compounds 2, 15, 20, and 21 can significantly inhibit the enzyme activity of PTP1B in a dose-dependent manner, with inhibitory concentration 50 ($IC_{50}$) values of $29.08{\mu}M$, $21.27{\mu}M$, $28.12{\mu}M$, and $26.59{\mu}M$, respectively. The results suggested that Panax notoginseng leaves might have potential as a new therapeutic agent for the treatment of diabetes.

Flexible Cu2O/Cu film self-powered photodetector for high visible light selection and fast response

Liu Yonghao,Zhao Dawei,Sun Ximing,Cui Feng,Zhang Shan,Shang Xue,Xuan Zhen,Xiao Juqing,Wang Jiapeng,Ren Yandong 한국물리학회 2024 Current Applied Physics Vol.58 No.-

Spectral selection is one of the key performance parameters for visible light photodetectors (VLPD). However, as the absorbing layer of the VLPD, the semiconductor has strong ultraviolet light absorption, leading to poor visible light selectivity of the VLPD. This work fabricated a flexible photovoltaic VLPD based on Cu2O/Cu Schottky junction by annealing Cu foil. Under zero bias, the Cu2O/Cu VLPD showed the responsivity of 14 mA/W, the response time of 1 ms, and the detectivity of 8.8 × 1011 Jones to 620 nm light. Moreover, the detection band of the device is in the range of 500–640 nm, indicating excellent visible light selectivity. Optical and electrical characterization shows that the high visible selectivity of the device is mainly attributed to the fact that the penetration depth of visible light in Cu2O film matches the position of the Cu2O/Cu Schottky junction. This, in turn, induces the effective separation of the photogenerated carriers excited by the visible light. In addition, the bend detection performance of the device is demonstrated. This work provides a reference for improving the spectral selectivity of visible photodetectors.

Preparation and Investigation of Ulex Europaeus Agglutinin IConjugated Liposomes as Potential Oral Vaccine Carriers

KeXin Li,DaWei Chen,XiuLi Zhao,HaiYang Hu,ChunRong Yang,DaHai Pang 대한약학회 2011 Archives of Pharmacal Research Vol.34 No.11

We prepared and optimized Ulex europaeus agglutinin I (UEAI)-modified Bovine serum albumin (BSA)-encapsulating liposomes (UEAI-LIP) as oral vaccine carriers and examined the feasibility of inducing systemic and mucosal immune responses by oral administration of UEAILIP. The prepared systems were characterized in vitro for their average size, zeta potential,encapsulation efficiency (EE%) and conjugation efficiency (CE%). In vitro release studies indicated that the presence of UEAI around the optimized liposomes was able to prevent a burst release of loaded BSA and provide sustained release of the encapsulated protein. In vivo immune-stimulating results in KM mice showed that BSA given intramuscularly generated systemic response only but both systemic and mucosal immune responses could be induced simultaneously in the groups in which BSA-loaded liposomes (LIP) and UEAI-LIP were administered intragastrically. Furthermore, the modification of UEAI on the surface of liposomes could further enhance the IgA and IgG levels obviously. In conclusion, this study demonstrated the high potential of lectin-modified liposomes containing the antigen as carriers for oral vaccine.

Research on prefabricated concrete beam-column joint with high strength bolt-end plate

Li Shufeng,Zhao Di,Li Qingning,Zhao Huajing,Zhang Jiaolei,Yuan Dawei 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.74 No.3

Many prefabricated concrete frame joints have been proposed, and most of them showed good seismic performance. However, there are still some limitations in the proposed fabricated joints. For example, for prefabricated prestressed concrete joints, prefabricated beams and prefabricated columns are assembled as a whole by the pre-stressed steel bar and steel strand in the beams, which brings some troubles to the construction, and the reinforcement in the core area of the joints is complex, and the mechanical mechanism is not clear. Based on the current research results, a new type of fabricated joint of prestressed concrete beams and confined concrete columns is proposed. To study the seismic performance of the joint, the quasi-static test is carried out. The test results show that the nodes exhibit good ductility and energy dissipation. According to the experimental fitting method and the “fixed point pointing” law, the resilience model of this kind of nodes is established, and compared with the experimental results, the two agree well, which can provides a certain reference for elasto-plastic seismic response analysis of this type of structure. Besides, based on the analysis of the factors affecting the shear capacity of the node core area, the formula of shear capacity of the core area of the node is proposed, and the theoretical values of the formula are consistent with the experimental value.

Novel Water-Air Circulation Quenching Process for AISI 4140 Steel

Liyun Zheng,Dawei Zheng1,Lixin Zhao,Lihui Wang,Kai Zhang 대한금속·재료학회 2013 METALS AND MATERIALS International Vol.19 No.6

AISI 4140 steel is usually used after quenching and tempering. During the heat treatment process in industry production, there are some problems, such as quenching cracks, related to water-cooling and low hardness due to oil quenching. A water-air circulation quenching process can solve the problems of quenching cracks with water and the high cost quenching with oil, which is flammable, unsafe and not enough to obtain the required hardness. The control of the water-cooling and air-cooling time is a key factor in the process. This paper focuses on the quenching temperature, water-air cycle time and cycle index to prevent cracking for AISI 4140 steel. The optimum heat treatment parameters to achieve a good match of the strength and toughness of AISI 4140 steel were obtained by repeated adjustment of the water-air circulation quenching process parameters. The tensile strength, Charpy impact energy at -10 °C and hardness of the heat treated AISI 4140 steel after quenching and tempering were approximately 1098 MPa, 67.5 J and 316 HB, respectively.