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Effect of hydrothermal time on the structure and property of graphene oxide membrane
Tran Van Khai,Pham Thuy Trang,Le Ngoc Long,Le Van Thang,Tran Duc Chau,Vuong Vinh Dat,Mai Thanh Phong 한양대학교 세라믹연구소 2021 Journal of Ceramic Processing Research Vol.22 No.4
Two dimensional graphene oxide (GO) has potential application in membrane separation owing to its unique structure andphysicochemical properties. In this study, the reduced graphene oxide (rGO) was synthesized from GO via hydrothermaltreatment at 160 oC for 1, 2, 3 and 4 h, and the rGO membranes were prepared on cellulose nitrate supporting membranesby vacuum filtration. The structural change and chemical composition of GO were investigated using X-ray diffraction (XRD),Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM),atomic force microscopy (AFM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS) andcontact angle measurements. The result shows that uniformly intact rGO membranes with good hydrophobicity could beachieved by adjusting the reduction degree of GO through changing the hydrothermal reaction time. The huge improvementof the hydrophobic property of rGO could be attributed to the removal of the most the hydrophilic oxygen-containingfunctional groups on the surface of GO. Additionally, the structure, chemical composition, and d-spacing of the GO can alsobe controlled by adjusting the reduction time. This method holds great potential because it can be prepared in large quantitiesat low cost, and suitable for applications in membrane technologies.
( Phil Jun Lee ),( Chau Ha Pham ),( Nguyen Thi Thanh Thuy ),( Hye-jin Park ),( Sung Hoon Lee ),( Hee Min Yoo ),( Namki Cho ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.2
This study aimed to investigate the neuroprotective effects of 1-methoxylespeflorin G11 (MLG), a pterocarpan, against glutamate-induced neurotoxicity in neuronal HT22 hippocampal cells. The protective effects of MLG were evaluated using MTT assay and microscopic analysis. The extent of apoptosis was studied using flow cytometric analysis performed on the damaged cells probed with annexin V/propidium iodide. Moreover, mitochondrial reactive oxygen species (ROS) were assessed using flow cytometry through MitoSOXTM Red staining. To determine mitochondrial membrane potential, staining with tetramethylrhodamine and JC-1 was performed followed by flow cytometry. The results demonstrated that MLG attenuates glutamate-induced apoptosis in HT22 cells by inhibiting intracellular ROS generation and mitochondrial dysfunction. Additionally, MLG prevented glutamate-induced apoptotic pathway in HT22 cells through upregulation of Bcl-2 and downregulation of cleaved PARP-1, AIF, and phosphorylated MAPK cascades. In addition, MLG treatment induced HO-1 expression in HT22 cells. These results suggested that MLG exhibits neuroprotective effects against glutamate-induced neurotoxicity in neuronal HT22 cells by inhibiting oxidative stress and apoptosis.
Kiem, Phan Van,Anh, Hoang Le Tuan,Nhiem, Nguyen Xuan,Minh, Chau Van,Thuy, Nguyen Thi Kim,Yen, Pham Hai,Hang, Dan Thuy,Tai, Bui Huu,Mathema, Vivek Bhakta,Koh, Young-Sang,Kim, Young Ho The Pharmaceutical Society of Japan 2012 Chemical & pharmaceutical bulletin Vol.60 No.2
<P>The rhizomes of <I>Hedychium coronarium</I> have been used for the treatment of inflammation, skin diseases, headache, and sharp pain due to rheumatism in traditional medicine. From this plant, two new labdanes, 15-methoxylabda-8(17),11<I>E</I>,13-trien-16,15-olide (<B>1</B>) and 16-methoxylabda-8(17),11<I>E</I>,13-trien-15,16-olide (<B>3</B>), named hedycoronens A and B, as well as four known, labda-8(17),11,13-trien-16,15-olide (<B>2</B>), 16-hydroxylabda-8(17),11,13-trien-15,16-olide (<B>4</B>), coronarin A (<B>5</B>), and corronarin E (<B>6</B>) were isolated. Their chemical structures were elucidated by mass, 1D- and 2D-nuclear magnetic resonance (NMR) spectroscopy. They were evaluated for inhibitory effects on the lipopolysaccharide (LPS)-stimulated production of pro-inflammatory cytokines in bone marrow-derived dendritic cells. Among of them, compounds <B>1</B>—<B>3</B> were potent inhibitors of LPS-stimulated interleukin-6 (IL-6) and IL-12 p40, with IC<SUB>50</SUB> ranging from 4.1±0.2 to 9.1±0.3 μ<SMALL>M</SMALL>. Compounds <B>1</B> and <B>3</B> showed moderate inhibitory activity on the tumor necrosis factor-α (TNF-α) production with IC<SUB>50</SUB> values of 46.0±1.3 and 12.7±0.3 μ<SMALL>M</SMALL>. The remains of compounds showed inactivity. These results warrant further studies concerning the potential anti-inflammatory benefits of labdane-diterpenes from <I>H. coronarium</I>.</P>