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811.
Wonbaek Kim Seung-Mi Kwak Chang-Yul Suh Jae-Won Lim Sung-Wook Cho In-Jin Shon 《Research on Chemical Intermediates》2013,39(6):2339-2349
Pure Ti and Si powders were milled in a horizontal-rotation ball mill and in a high-energy ball mill to synthesize Ti5Si3 powders. The high-energy ball milling produced nanosized single-phase Ti5Si3 particles. Meanwhile, no reaction occurred during the horizontal milling. The two milled powders were consolidated using the high-frequency induction heated sintering method. A dense nanostructured Ti5Si3 compact was consolidated within 2 min using the mechanically synthesized Ti5Si3 powder. The retainment of nanoscale structure during sintering is believed to be the reason for the good mechanical properties of the Ti5Si3 compact. In comparison, the horizontally milled powder reacted to form Ti5Si3 partially on sintering. It is believed that the enhanced toughness of the horizontally milled samples may be due to the crack-deterring effect of softer Si/Ti grains. 相似文献
812.
Jeng-Hun Suh Sang-Wook Lee Yong-Sang Ryu Youngjoo Sohn 《Molecular Crystals and Liquid Crystals》2014,600(1):81-87
We present the coarsening dynamics of a liquid-ordered (Lo) domain in a supported lipid membrane under an electric field. In a relatively small nanosmooth region surrounded by geometrical walls of nanocorrugated regions, full coarsening of the Lo domain was produced while in a large nanosmooth region, an intermediate, less-ordered Lo domain was developed so that the diffusion of charged phospholipids in the liquid-disordered (Ld) domain was allowed across the geometrical walls in the presence of an electric field. No appreciable diffusion of the charged lipids into a fully coarsened Lo domain by the electric field implies that the structural ordering of the membrane components plays a significant role on the formation of lipid rafts for biological processes. 相似文献
813.
Young Han Lee Daekeon Lim Eunju Kim Sungjun Kim Ho-Taek Song Jin-Suck Suh 《Magnetic resonance imaging》2014
Background and Purpose
Fluid-sensitive MR imaging in postoperative evaluation is important, however, metallic artifacts is inevitable. The purpose is to investigate the feasibility of fat-saturated slice encoding for metal artifact correction (SEMAC)-corrected T2-weighted magnetic resonance (MR) at 3T in patients with spinal prostheses.Methods
Following institutional review board approval, 27 SEMAC-encoded spinal MRs between September 2012 and October 2013 in patients with spinal metallic prostheses were analyzed. The MR images were scanned on a 3T MR system including SEMAC-corrected and uncorrected fast spin echo (FSE) T2-weighted MR images with fat-saturation. Two musculoskeletal radiologists compared the image sets and qualitatively analyzed the images using a five-point scale in terms of artifact reduction around the prosthesis, visualization of the prosthesis and pedicle, and intervertebral neural foramina. Quantitative assessments were performed by calculating the ratio of signal intensity from the fixated vertebra and that from upper level vertebra. For statistical analyses, paired t-test was used.Results
Fat-saturated SEMAC-corrected T2-weighted MR images enabled significantly improved metallic artifact reduction (P < 0.05). Quantitative evaluation of the signal intensity ratio of screw-fixated vertebra and upper level vertebra showed a significantly lower ratio on fat-saturated SEMAC images (P < 0.05), however, the high signal intensity of signal pile-up could be not completely corrected.Conclusion
SEMAC correction in fat-suppressed T2-weighted MR images can overcome the signal loss of metallic artifacts and provide improved delineation of the pedicle screw and peri-prosthetic region. Signal pile-up, however, could not be corrected completely, therefore readers should be cautious in the evaluation of marrow around the prosthesis. 相似文献814.
Do-Wan Lee Ji-Yeon Park Sang-Young Kim Hae-Jin Park Seu-Ran Lee Tae-Suk Suh Bo-Young Choe 《Applied magnetic resonance》2014,45(12):1377-1388
Ethanol is the most commonly abused intoxicating substance among young and middle-aged adults, and ranks highly as a cause of disability and mortality. A pattern of heavy consumption, called binge drinking, leads to various psychiatric disorders. However, to the best of our knowledge, assessments of the influence of short-term binge ethanol (SBE) intoxication on cerebral metabolite changes in human and rat models are scarce. We used in vivo 1H magnetic resonance spectroscopy (1H-MRS) to quantitatively assess neurochemical responses in hippocampus in a rat model of SBE intoxication. Seven SBE-exposed rats received an initial dose of 5.0-g/kg ethanol (30 %-w/v solution) through gavage and additional doses of 2.0-g/kg ethanol (25 %-w/v solution), every 8 hour for 4 days. Six rats in sham control group (CNTL) received an equivalent volume of distilled water at comparable times. Sixty minutes after last gavage session, in vivo 1H-MRS scans were obtained from all rats using a 4.7 Tesla animal scanner. For neurochemical analysis, a single voxel was positioned in the hippocampal region and spectra were fitted for the quantification of 17 cerebral neurochemical signals. In hippocampus, the concentration of total choline-containing compound signals (tCho: [glycerophosphocholine] + [phosphocholine]) was significantly lower in SBE-exposed rats than in CNTL rats. Moreover, gamma-aminobutyric acid (GABA)/total creatine (tCr: creatine + phosphocreatine), tCho/tCr, and tCho/total N-acetyl-aspartate (tNAA: N-acetyl-aspartate + N-acetyl-aspartyl-glutamate) ratios were significantly lower in SBE-exposed rats than CNTL rats. We determined that tCho, GABA, and tNAA signals were highly sensitive to short-term binge ethanol intoxication, which provides insights into neurochemical alterations associated with ethanol abuse. 相似文献
815.
Enhancing CO2 Separation Ability of a Metal–Organic Framework by Post‐Synthetic Ligand Exchange with Flexible Aliphatic Carboxylates
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Dae Ho Hong Prof. Myunghyun Paik Suh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(2):426-434
A series of porous metal–organic frameworks having flexible carboxylic acid pendants in their pores (UiO‐66‐ADn: n=4, 6, 8, and 10, where n denotes the number of carbons in a pendant) has been synthesized by post‐synthetic ligand exchange of terephthalate in UiO‐66 with a series of alkanedioic acids (HO2C(CH2)n?2CO2H). NMR, IR, PXRD, TEM, and mass spectral data have suggested that a terephthalate linker in UiO‐66 was substituted by two alkanedioate moieties, resulting in free carboxyl pendants in the pores. When post‐synthetically modified UiO‐66 was partially digested by adjusting the amount of added HF/sample, NMR spectra indicated that the ratio of alkanedioic acid/terephthalic acid was increased with smaller amounts of acid, implying that the ligand substitution proceeded from the outer layer of the particles. Gas sorption studies indicated that the surface areas and the pore volumes of all UiO‐66‐ADns were decreased compared to those of UiO‐66, and that the CO2 adsorption capacities of UiO‐66‐ADn (n=4, 8) were similar to that of UiO‐66. In the case of UiO‐66‐AD6, the CO2 uptake capacity was 34 % higher at 298 K and 58 % higher at 323 K compared to those of UiO‐66. It was elucidated by thermodynamic calculations that the introduction of flexible carboxyl pendants of appropriate length has two effects: 1) it increases the interaction enthalpy between the host framework and CO2 molecules, and 2) it mitigates the entropy loss upon CO2 adsorption due to the formation of multiple configurations for the interactions between carboxyl groups and CO2 molecules. The ideal adsorption solution theory (IAST) selectivity for CO2 adsorption over that of CH4 was enhanced for all of the UiO‐66‐ADns compared to that of UiO‐66 at 298 K. In particular, UiO‐66‐AD6 showed the most strongly enhanced CO2 uptake capacity and significantly increased selectivity for CO2 adsorption over that of CH4 at ambient temperature, suggesting that it is a promising material for sequestering CO2 from landfill gas. 相似文献
816.
Jing-Nan Liu Dong-Hyeon Suh Eun-Mi Yang Seung-Ihm Lee Hae-Sim Park Yoo Seob Shin 《Experimental & molecular medicine》2014,46(9):e113
Although some studies have explained the immunomodulatory effects of statins, the exact mechanisms and the therapeutic significance of these molecules remain to be elucidated. This study not only evaluated the therapeutic potential and inhibitory mechanism of simvastatin in an ovalbumin (OVA)-specific asthma model in mice but also sought to clarify the future directions indicated by previous studies through a thorough review of the literature. BALB/c mice were sensitized to OVA and then administered three OVA challenges. On each challenge day, 40 mg kg−1 simvastatin was injected before the challenge. The airway responsiveness, inflammatory cell composition, and cytokine levels in bronchoalveolar lavage (BAL) fluid were assessed after the final challenge, and the T cell composition and adhesion molecule expression in lung homogenates were determined. The administration of simvastatin decreased the airway responsiveness, the number of airway inflammatory cells, and the interleukin (IL)-4, IL-5 and IL-13 concentrations in BAL fluid compared with vehicle-treated mice (P<0.05). Histologically, the number of inflammatory cells and mucus-containing goblet cells in lung tissues also decreased in the simvastatin-treated mice. Flow cytometry showed that simvastatin treatment significantly reduced the percentage of pulmonary CD4+ cells and the CD4+/CD8+ T-cell ratio (P<0.05). Simvastatin treatment also decreased the expression of the vascular cell adhesion molecule 1 and intercellular adhesion molecule 1 proteins, as measured in homogenized lung tissues (P<0.05) and human epithelial cells. The reduction in the T cell influx as a result of the decreased expression of cell adhesion molecules is one of the mechanisms by which simvastatin attenuates airway responsiveness and allergic inflammation. Rigorous review of the literature together with our findings suggested that simvastatin should be further developed as a potential therapeutic strategy for allergic asthma. 相似文献
817.
Inside Back Cover: An Unusual Protein–Protein Interaction through Coupled Unfolding and Binding (Angew. Chem. Int. Ed. 37/2014)
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818.
describe a one-step UV-replica molding method for fabricating a biomimetic dual-scale hierarchical structure. The use of UV-curable, acrylate-functionalized perfluoropolyethers allows for a high fidelity replication of a low-energy surface with multiscale texture, thereby directly creating a superhydrophobic surface without any complicated processing. The superhydrophobic surface can simply be transformed selectively into a superhydrophilic surface by exposure to deep ultraviolet light. The prepared surface is inert to chemicals and solvents and maintains its wettability over a long period of time. 相似文献
819.
Eui Hyun Suh Sang Beom Kim Jaemin Jung Jaeyoung Jang 《Angewandte Chemie (International ed. in English)》2023,62(37):e202304245
P-type chemical doping (p-doping) is a key technique to modulate the optical, electrical, and electronic properties of organic semiconductors. However, typical functional groups in organic p-dopants have insufficient electron-withdrawing strength, and the inevitable diffusion of dopants in host matrices degrades doping stabilities. Herein, we utilize extremely electron-withdrawing Lewis-paired CN groups as a new class of building blocks for designing unprecedentedly strong organic p-dopants with excellent doping stability. Various Lewis acids are paired with CN-functionalized conjugated molecules in the solution state, which strengthens the electron-withdrawing properties of CN groups almost twofold. The large dopants afford outstanding doping stability against continuous heating and long-term atmospheric exposure, which is promising for practical applications in devices. Given the broad applicability of this simple combinatorial approach, it may impact many fields of (opto)electronics. 相似文献
820.
The enhancement of surface enhanced Raman scattering (SERS) at the junction of linearly joined silver nanorods (31 nm in diameter) deposited in the pores of anodic aluminum oxide templates was studied systematically by excitation with a 632.8 nm laser line. The single and joined silver nanorod arrays showed a similar extinction spectrum when their length was the same. Maximum enhancement was observed from the junction system of two nanorods of the same size with a total length of 62 nm. This length also corresponded to the optimum length of single nanorods for SERS by excitation with a 632.8 nm laser line. The enhancement at the junction was approximately 40 times higher than that of the 31 nm single nanorod, while it was 4 times higher than that of the 62 nm single nanorod. The enhancement factor at the junction after oxide removal was approximately 3.9 x 10 (9). 相似文献