241 research outputs found
CH4 recovery and CO2 sequestration using flue gas in natural gas hydrates as revealed by a micro-differential scanning calorimeter
No full textThe CH4-flue gas replacement in naturally occurring gas hydrates has attracted significant attention due to its potential as a method of exploitation of clean energy and sequestration of CO2. In the replacement process, the thermodynamic and structural properties of the mixed gas hydrates are critical factors to predict the heat flow in the hydrate-bearing sediments and the heat required for hydrate dissociation, and to evaluate the CO2 storage capacity of hydrate reservoirs. In this study, the C-13 NMR and gas composition analyses confirmed that the preferential enclathration of N-2 molecules in small 5(12) cages of structure I hydrates improved the extent of the CH4 recovery. A high pressure micro-differential scanning calorimeter (HP mu-DSC) provided reliable hydrate stability conditions and heat of dissociation values in the porous silica gels after the replacement, which confirmed that CH4 in the hydrates was successfully replaced with flue gas. A heat flow change associated with the dissociation and formation of hydrates was not noticeable during the CH4-flue gas replacement. Therefore, this study reveals that CH4-flue gas swapping occurs without structural transitions and significant hydrate dissociations. (C) 2015 Elsevier Ltd. All rights reserved.close2
Cytotoxic sesquiterpene glucosides from Fissistigma pallens
No full textThinh, Ngo Sy, Thu, Nguyen Thi Bich, Ngoc, Tran Minh, Khoi, Nguyen Minh, Tai, Bui Huu, Kiem, Phan Van, Minh, Chau Van, Nhiem, Nguyen Xuan, Seo, Yohan, Namkung, Wan, Park, SeonJu, Kim, Seung Hyun (2020): Cytotoxic sesquiterpene glucosides from Fissistigma pallens. Phytochemistry (112255) 172: 1-7, DOI: 10.1016/j.phytochem.2019.112255, URL: http://dx.doi.org/10.1016/j.phytochem.2019.11225
Fig. 2 in Cytotoxic sesquiterpene glucosides from Fissistigma pallens
No full textFig. 2. The key HMBC and COSY correlations of compounds 1–6.Published as part of Thinh, Ngo Sy, Thu, Nguyen Thi Bich, Ngoc, Tran Minh, Khoi, Nguyen Minh, Tai, Bui Huu, Kiem, Phan Van, Minh, Chau Van, Nhiem, Nguyen Xuan, Seo, Yohan, Namkung, Wan, Park, SeonJu & Kim, Seung Hyun, 2020, Cytotoxic sesquiterpene glucosides from Fissistigma pallens, pp. 1-7 in Phytochemistry (112255) 172 on page 4, DOI: 10.1016/j.phytochem.2019.112255, http://zenodo.org/record/829425
Fig. 3 in Cytotoxic sesquiterpene glucosides from Fissistigma pallens
No full textFig. 3. The key NOESY correlations of compounds 1–6.Published as part of Thinh, Ngo Sy, Thu, Nguyen Thi Bich, Ngoc, Tran Minh, Khoi, Nguyen Minh, Tai, Bui Huu, Kiem, Phan Van, Minh, Chau Van, Nhiem, Nguyen Xuan, Seo, Yohan, Namkung, Wan, Park, SeonJu & Kim, Seung Hyun, 2020, Cytotoxic sesquiterpene glucosides from Fissistigma pallens, pp. 1-7 in Phytochemistry (112255) 172 on page 4, DOI: 10.1016/j.phytochem.2019.112255, http://zenodo.org/record/829425
Fig. 1 in Cytotoxic sesquiterpene glucosides from Fissistigma pallens
No full textFig. 1. Chemical structures of compounds 1–7.Published as part of Thinh, Ngo Sy, Thu, Nguyen Thi Bich, Ngoc, Tran Minh, Khoi, Nguyen Minh, Tai, Bui Huu, Kiem, Phan Van, Minh, Chau Van, Nhiem, Nguyen Xuan, Seo, Yohan, Namkung, Wan, Park, SeonJu & Kim, Seung Hyun, 2020, Cytotoxic sesquiterpene glucosides from Fissistigma pallens, pp. 1-7 in Phytochemistry (112255) 172 on page 3, DOI: 10.1016/j.phytochem.2019.112255, http://zenodo.org/record/829425
Integration of Gold Nanoparticle-Carbon Nanotube Composite for Enhanced Contact Lifetime of Microelectromechanical Switches with Very Low Contact Resistance
No full textElectrical circuits require ideal switches with low power consumption for future electronic applications. However, transistors, the most developed electrical switches available currently, have certain fundamental limitations such as increased leakage current and limited subthreshold swing. To overcome these limitations, micromechanical switches have been extensively studied; however, it is challenging to develop micromechanical switches with high endurance and low contact resistance. This study demonstrates highly reliable microelectromechanical switches using nanocomposites. Nanocomposites consisting of gold nanoparticles (Au NPs) and carbon nanotubes (CNTs) are coated on contact electrodes as contact surfaces through a scalable and solution-based fabrication process. While deformable CNTs in the nanocomposite increase the effective contact area under mechanical loads, highly conductive Au NPs provide current paths with low contact resistance between CNTs. Given these advantages, the switches exhibit robust switching operations over 5 x 10(6) cycles under hot-switching conditions in air. The switches also show low contact resistance without subthreshold region, an extremely small leakage current, and a high on/off ratio.
Dyrk1A Phosphorylates p53 and Inhibits Proliferation of Embryonic Neuronal Cells
No full textDown syndrome (DS) is associated with many neural defects, including reduced brain size and impaired neuronal proliferation, highly contributing to the mental retardation. Those typical characteristics of DS are closely associated with a specific gene group "Down syndrome critical region" (DSCR) on human chromosome 21. Here we investigated the molecular mechanisms underlying impaired neuronal proliferation in DS and, more specifically, a regulatory role for dual-specificity tyrosine-(Y) phosphorylation-regulated kinase 1A (Dyrk1A), a DSCR gene product, in embryonic neuronal cell proliferation. We found that Dyrk1A phosphorylates p53 at Ser-15 in vitro and in immortalized rat embryonic hippocampal progenitor H19-7 cells. In addition, Dyrk1A-induced p53 phosphorylation at Ser-15 led to a robust induction of p53 target genes (e. g. p21(CIP1)) and impaired G(1)/G(0)-S phase transition, resulting in attenuated proliferation of H19-7 cells and human embryonic stem cell-derived neural precursor cells. Moreover, the point mutation of p53-Ser-15 to alanine rescued the inhibitory effect of Dyrk1A on neuronal proliferation. Accordingly, brains from embryonic DYRK1A transgenic mice exhibited elevated levels of Dyrk1A, Ser-15 (mouse Ser-18)-phosphorylated p53, and p21(CIP1) as well as impaired neuronal proliferation. These findings suggest that up-regulation of Dyrk1A contributes to altered neuronal proliferation in DS through specific phosphorylation of p53 at Ser-15 and subsequent p21(CIP1) induction
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