Luteolin Modulates the NF-E2-Related Factor 2/Glutamate–Cysteine Ligase Pathway in Rats with Spinal Cord Injury

Jian Fu,Wei Xu,Yongzhe Zhang,Haibin Sun,Jianhui Zhao 한국식품영양과학회 2021 Journal of medicinal food Vol.24 No.3

Spinal cord ischemia–reperfusion injury (SCII) easily causes unalterable neurological deficits. We previously demonstrated that the flavonoid luteolin (LU) has strong antioxidant, anti-inflammatory, and other neuroprotective efficacies against SCII. In our current study, we examined the contributions of the NF-E2-related factor 2 (Nrf2)/glutamate–cysteine ligase (GCL) pathway to LU-mediated neuroprotection in the transient abdominal aorta occlusion rat model of SCII. Rats were divided into four groups: Sham surgery, SCII alone, SCII plus LU pretreatment (SCII + LU), and SCII plus cotreatment with LU and the Nrf2 inhibitor ML385 (SCII + LU + ML385). The Basso–Beattie–Bresnahan (BBB) scale was used to assess neurological function, hematoxylin and eosin staining to evaluate pathological change to the spinal cord, and enzyme-linked immunosorbent assay to measure tissue markers of oxidative stress and inflammation induced by SCII. Mitochondrial injury and apoptosis were examined by flow cytometry and expression levels of Nrf2, GCL catalytic subunit (GCLc), and GCL modifier subunit (GCLm) by real-time quantitative polymerase chain reaction. LU pretreatment significantly enhanced recovery of motor function as evidenced by the BBB score and attenuated the pathological damage. Furthermore, LU effectively enhanced the antioxidative activity, alleviated mitochondrial swelling, decreased the expression levels of several proinflammatory cytokines after SCII, and significantly upregulated Nrf2, GCLc, and GCLm expression levels. Cotreatment with ML385 reversed all these protective effects of LU except the anti-inflammatory response. Collectively, these findings indicate that the neuroprotective efficacy of LU depends on suppression of oxidative stress and preservation of mitochondrial function through signaling pathways involving Nrf2 activation and downstream gene expression.

Use of Computational Fluid Dynamics for the Design and Analysis of Gas Turbine Combustors

Niveditha Krishnamoorthy,Piyush Thakre,Yongzhe Zhang,Richard Clayton,Graham Goldin,Rajesh Rawat 한국추진공학회 2015 한국추진공학회 학술대회논문집 Vol.2015 No.11

The use of computational fluid dynamics (CFD) for the design and analysis of the flow and combustion in gas turbine combustors is considered to be a cost effective alternative to time-consuming and expensive design of experiments studies. With stringent emission regulations being enforced for these combustion systems, efforts towards optimization of the combustor geometry, and its operating conditions to minimize fuel consumption, emissions, and cost are also being undertaken using CFD. Reacting flow modeling in gas turbine combustors is a multi-scale, multi-physics process which requires an adequate representation of the flow, chemistry, and heat transfer mechanisms taking place in these systems. The models/approximations used in simulating gas turbine combustors directly influence the predictive capability of the simulations. In this study, the commercial software STAR-CCM+ is used model all the processes taking place in a gas turbine combustor. STAR-CCM+ solves the Navier-Stokes equation using the finite volume formulation. The choice to represent the combustion chemistry via global reactions, tabulated methodology, or detailed kinetic modeling is available for premixed, non-premixed and partially premixed combustion regimes. The combustion model selection is typically driven by the intended purpose of the simulation. Radiative heat transfer is modeled using the discrete ordinates methodology. In order to study the mechanical durability of various components in these systems, a full conjugate heat transfer (CHT) analysis is also performed where, the liner and other solids are explicitly modeled in the fully-coupled simulation. In this investigation, both the Reynolds Averaged Simulation (RANS) methodology and the Large-Eddy Simulation (LES) methodology are explored and the results are summarized.

Neuroprotective Effects of Luteolin Against Spinal Cord Ischemia–Reperfusion Injury by Attenuation of Oxidative Stress, Inflammation, and Apoptosis

Jian Fu,Haibin Sun,Yongzhe Zhang,Wei Xu,Chuan Wang,Yanwei Fang,Jianhui Zhao 한국식품영양과학회 2018 Journal of medicinal food Vol.21 No.1

Luteolin (LU) is a widely distributed flavonoid with multitarget effects. The objective of this study was to determine whether LU could reduce the ischemia–reperfusion injury of the spinal cord (SCII) in a rat model. Forty-eight rats were divided into four groups: sham, SCII, SCII+L-LU (50 mg/kg), and SCII+H-LU (100 mg/kg). Abdominal aortic occlusion was carried out for 40 min in all groups. Hindlimb motor functions were evaluated using the Tarlov scoring system. Nissl and terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling (TUNEL) staining were used to detect cell survival and apoptosis in the spinal cord. Spinal cord samples were taken for determination of malondialdehyde, xanthine oxidase, superoxide dismutase, and glutathione peroxidase activities. The levels of tumor necrosis factor-α, interleukin (IL)-1β, and IL-18 were assessed using ELISA kits to examine the inflammatory responses in the spinal cord. Western blot analysis was used to examine the expression of nuclear factor erythroid 2-related factor (Nrf2) and nod-like receptor pyrin domain-containing 3 protein (NLRP3) levels. We found that LU pretreatment significantly improved the locomotor function of rats after SCII, increased neuron survival, and inhibited apoptosis in the spinal cord. Furthermore, the oxidative stress and inflammatory response were significantly suppressed upon treatment with LU. Finally, LU upregulated Nrf2 levels and downregulated NLRP3 protein expression in SCII tissues. Thus, LU exhibited a neuroprotective effect following SCII by alleviating oxidative stress and inhibiting inflammatory responses and cell apoptosis. The possible mechanism may be related to the activation of Nrf2 and inhibition of NLRP3 inflammasome pathway.

SYNERGISTIC EFFECT OF SURFACE PLASMON RESONANCE AND CONSTRUCTED THREE- DIMENSIONAL INTERWOVEN STRUCTURED TiO 2 PHOTOANODE FOR DYE-SENSITIZED SOLAR CELLS

WANGPING RAO,JIANXI YAO,SONGYUAN DAI,BING ZHANG,YONGZHE ZHANG,LI XIAO 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.5

We demonstrate a strategy for incorporating plasmon resonant metallic nanoparticles in theconstruction of the three-dimensional (3D) interwoven structured TiO 2 photoanodes. The 3Dinterwoven structure contained continuous TiO 2 skeleton and numerous interconnected macro/mesopores, which supplied e®ective straight path for electron transfer and high speci¯c surfacearea for dye load. Localized surface plasmon resonance (SPR) was produced by the addition ofgold nanoparticles (AuNPs), which increased the light absorption of the photoanodes moree®ectively. The synergistic e®ect of SPR with constructed TiO 2 nanostructures has been in-vestigated, and was con¯rmed by ¯eld-emission scanning electron microscope (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy(XPS), UV-Vis absorption spectra, J – V characteristics, and electrochemical impedance spec-troscopy (EIS) analysis. It was found that the range and strength of light absorption of TiO 2photoanodes, the photon capture ability of the dye molecules, the photoelectric conversion e±-ciency were signi¯cantly increased while the electron transfer resistance decreased due to theincorporation of AuNPs compared to the P25 and Au-free photoanode. The related photoelectricperformance enhancement mechanisms, and surface-plasmon resonances in dye-sensitized solarcells (DSSCs) with Au nanostructures were analyzed and discussed.

Enhanced Performance of Near-Infrared-Absorption CdSeTe Quantum Dot-Sensitized Solar Cells Via Octa-Aminopropyl Polyhedral Oligomeric Silsesquioxane Modification

Xue Zhao,Ruina Ma,An Du,Yinan Zhang,Xue Zhao,Yongzhe Fan,Xiaoming Cao 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.7

The charge recombination caused by surface defects limits photovoltaic properties of quantum dot-sensitized solar cells (QDSSCs), which can be suppressed by modifying organic or inorganic molecules and atomic ligands. In this paper, octa-aminopropyl polyhedral oligomeric silsesquioxane (OA-POSS) connected and modified near-infrared absorption CdSeTe quantum dots (QDs) through coupling agent (1-ethyl-3-3-dimethylaminopropyl carbodiimide hydrochloride). The results suggest that OA-POSS reduces the surface defects of CdSeTe QDs and suppresses charge recombination. Therefore, the power conversion efficiency improves nearly 41%, which increases from 2.00% to 2.82%.

Formation of Ohmic contacts on laser irradiated n-type 6H-SiC without thermal annealing

Yan Wu,Lingfei Ji,Zhenyuan Lin,Minghui Hong,Sicong Wang,Yongzhe Zhang 한국물리학회 2019 Current Applied Physics Vol.19 No.4

In this work, KrF excimer laser irradiation of n-type SiC is used to form Ohmic contacts at the interfaces between the irradiated SiC and various types of metals with different work functions without subsequent thermal annealing. Ohmic contacts are formed between laser-treated 6H-SiC and Ti at a laser fluence of 0.7 J/cm2. Moreover, in the fluence range of 0.7–1.3 J/cm2, Ohmic characteristics are also observed between irradiated 6HSiC and Au, which is a representative inert metal. The laser-induced heavy doping effect reduces the thickness of the Schottky barrier between the metal and SiC, and the formation of graphene sheets on the irradiated SiC surface reduces the barrier height, resulting in the direct formation of Ohmic contacts. Our findings thus demonstrate the potential of this laser treatment method to achieve Ohmic contacts between n-type SiC and a broad range of metal electrodes without requiring high-temperature annealing.

한국과 중국 채집 담배가루이 지역계통의 B, Q biotype 분포 및 살충제 약제반응, 토마토황화잎말림바이러스 보독율 비교

Jeong, In-Hong,Park, Bueyong,Lee, Gwan-Seok,Wu, Qiong,Li, Feifei,Zhang, Zhenxing,Zhu, Yongzhe 한국환경생물학회 2020 환경생물 : 환경생물학회지 Vol.38 No.4

세계적인 침입해충 담배가루이(Bemisia tabaci Gennadius)의 한국 계통과 중국 계통의 유연관계를 알아보기 위하여 2019년에 채집한 두 계통들의 biotype 분포, 살충제 반응, 바이러스 보독율을 조사하고 차이를 분석하였다. 미토콘드리아 COI 유전자 서열을 이용하여 집단 분석한 결과 국내는 모든 지역계통에서 Q biotype만 발견되었으며, 중국은 B biotype (14.3%)과 Q biotype (85.7%)이 동시에 발견되었다. 담배가루이 Q biotype의 haplotpye 구성도 중국은 모두 Q1 그룹만 관찰되었고 Q1H1 (79.8%), Q1H2(20.2%)로 구성되어 있었으며, 한국은 Q1이 우세한 가운데 Q2도 관찰되었으며 Q1 그룹의 구성도 Q1H1 (1.7%), Q1H2 (97.5%)로 중국과는 크게 달랐다. 15종 살충제에 대한 약제반응은 국내 계통은 일부 약제를 제외하고 대부분 약제에서 충분한 살충력(mortality≥80%)을 보여주었으나 중국 계통은 40% 이하의 살충력을 보인 약제들이 다수 있었으며 한국보다는 높은 저항성을 갖고 있었다. 토마토 황화잎말림바이러스(TYLCV)의 보독율은 국내 계통에서는 발견되지 않았으며 중국의 경우 0~60%(평균 21.4%)가 발견되었다. 따라서 한국와 중국의 담배가루이 계통 간에는 유전적 조성과 살충제 반응, 바이러스 보독율에 있어서 큰 차이를 보여주었으며 양국의 담배가루이가 서로 다른 유입 패턴을 갖고 있음을 알 수 있었다. International trade is one of the primary ways that non-native species spread worldwide. Korea and China are geographically close and have a large mutual trade volume. To investigate the population movement of the invasive whitefly(Bemisia tabaci Gennadius) between the two countries, we compared the biotype distribution, insecticidal response, and the TYLCV(tomato yellow leaf curl virus) viruliferous rate of local populations collected in 2019. Based on the mitochondrial DNA COI sequences of B. tabaci, only the Q biotype was found in all populations in Korea, whereas the B biotype (14.3%) and Q biotype (85.7%) were found in China. In the haplotype composition of the B. tabaci Q biotype, only the Q1 group[Q1H1(79.8%) and Q1H2(20.2%)] was observed in China, but the Q1 group [Q1H1(1.7%) and Q1H2(97.5%)] and the Q2 group(only one individual) were found in Korea. The Korean populations showed high mortality(more than 80%) from 15 commercial insecticides, but the Chinese populations showed significantly low mortality from eight insecticides. No TYLCV infections were observed in the Korean populations while the average TYLCV viruliferous rate was 21.4% in the Chinese populations. Taken together, the results suggest that the population structures of B. tabaci in the two countries are different and may have different immigration histories.