http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Sang‑Wook Kim,Hyeon‑Woo Son,Taek‑Kyun Jung,Young‑Bum Chun,Yi‑Hyun Park,Ji‑Woon Lee,Soong‑Keun Hyun 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.4
The hot deformation behavior of advanced reduced-activation alloy (ARAA) was investigated using hot torsion tests. Thefl ow stress decreased as deformation temperature increased and as strain rate decreased. The fl ow behavior demonstratedthe typical dynamic recrystallization (DRX). Based on the constitutive analysis of peak stress, the activation energy for hotdeformation was found to be 330.3 kJ mol −1 . Peak stress was analyzed as a function of the Zener–Hollomon parameter, andcalculated and experimental values were in good agreement. A DRX kinetic model for ARAA was derived with deformationconditions based on the Avrami-type model. It was confi rmed that the volume fraction of dynamically recrystallized grainsincreased as deformation temperature increased and as strain rate decreased. The necklace structure and grain boundarybulging were observed in the deformed microstructure of ARAA. The suggested DRX mechanism for ARAA during hotworking is discontinuous DRX.
DJ-1 deficiency impairs synaptic vesicle endocytosis and reavailability at nerve terminals
Kyung, Jae Won,Kim, Jin-Mo,Lee, Wongyoung,Ha, Tae-Young,Cha, Seon-Heui,Chung, Kyung-Hwun,Choi, Dong-Joo,Jou, Ilo,Song, Woo Keun,Joe, Eun-Hye,Kim, Sung Hyun,Park, Sang Myun National Academy of Sciences 2018 Proceedings of the National Academy of Sciences Vol.115 No.7
<P>Mutations in DJ-1 (PARK7) are a known cause of early-onset autosomal recessive Parkinson's disease (PD). Accumulating evidence indicates that abnormalities of synaptic vesicle trafficking underlie the pathophysiological mechanism of PD. In the present study, we explored whether DJ-1 is involved in CNS synaptic function. DJ-1 deficiency impaired synaptic vesicle endocytosis and reavailability without inducing structural alterations in synapses. Familial mutants of DJ-1 (M26I, E64D, and L166P) were unable to rescue defective endocytosis of synaptic vesicles, whereas WT DJ-1 expression completely restored endocytic function in DJ-1 KO neurons. The defective synaptic endocytosis shown in DJ-1 KO neurons may be attributable to alterations in membrane cholesterol level. Thus, DJ-1 appears essential for synaptic vesicle endocytosis and reavailability, and impairment of this function by familial mutants of DJ-1 may be related to the pathogenesis of PD.</P>
Physical and chemical Effects on the sonication Treatment of chitosan solution
Lee, Keun Tai,Park, Seong Min,Park, Chan Kyu,Kim, Sang Moo 한국키틴키토산학회 1997 한국키틴키토산학회지 Vol.2 No.2
물리적 방법을 이용한 키토산 올리고당의 제조에 관한 기초 자료를 제시하기 위하여 키토산용액을 20kHz의 초음파로 처리하였으며, 초음파 처리 효과에 미치는 처리 조건의 영향을 조사하였다. 키토산 용액의 고유점도는 초음파 처리 5분까지는 급속하게 감소하였고 그 이후로는 서서히 감소하였다. 키토산 용액의 부피가 작을수록 초음파 처리효과는 컸으며, 키토산 용액의 온도는 초음파 처리에 별다른 효과가 없는 것으로 나타났다. 5분간 초음파 처리 후의 점도는 용매의 종류에 따라 큰 차이가 없었으나, acetate buffer의 경우 초음파 처리효과가 가장 컸다. pH가 높을수록 초음파 처리효과는 크게 나타났으며, 이온강도와 염의 종류에 따른 효과는 나타나지 않았다. 이상의 결과에서, 용액의 부피는 10~20ml, 온도는 20~30℃, 용액의 pH는 4.5, 그리고 용매의 종류는 acetate buffer로 하는 것이 최적 초음파 처리조건으로 추정된다. As the first step of studies related to production of chitooligosaccharides by physical methods, chitosan solution were sonicated with 20kHz and various treatment effects were examined to present fundamental data of sonicated chitosan solution. Intrinsic viscosity of chitosan solution sharply decreased from 3.76dl/g to 2.90dl/g until 5 minutes of sonication and then slowly decreased. With low volume of chitosan solution, sonication was very effective and temperature of chitosan solution slightly affected the efficiency of sonication. In case of changing the solvent, no significant differences were observed on the effect of sonication, however, acetate buffer had highest sonication effect among various solvents. The sonication effect was increased as the increasement of the value of pH, on the contrary, ionic strength and type of counterions showed no effect on sonication, With these results, we assumed that optimal sonication treatment would be as follows, solution volume was 10 ~20ml, temperature range was 20~30℃ , pH value of solution was 4.5 and type of solvent was acetate buffer
Ionic liquids as cosolvents for the lipase-catalyzed kinetic resolution of ketoprofen
Park, Saerom,Doan, Thanh Thi Ngoc,Koo, Yoon-Mo,Oh, Kyeong Keun,Lee, Sang Hyun Elsevier 2018 Molecular catalysis Vol.459 No.-
<P>This study examined the use of ionic liquids (ILs) as cosolvents for the Candida rugosa lipase-catalyzed enantioselective hydrolysis of racemic ketoprofen ethyl ester. To determine the effect of the IL anion structures on the lipase activity and enantioselectivity, six ILs containing the 1-butyl-3-methylimidazolium ([Bmim]) cation were used as cosolvents and their solvent properties were correlated with various reaction characteristics. The highest lipase activities were obtained using [Bmim] (BF 4 ] and [Bmim][MeSO4] as cosolvents. The enantioselectivity (E) of lipase was enhanced by a factor of 50 with 5% [Bmim][MeSO4]. Although the conversion, enantiomeric excess of product (ee(p)), and E value in 5% [Bmim][MeSO4] were 47.3%, > 99%, and similar to 300, respectively, the corresponding lipase stability is inadequate for commercial application. Excluding [Bmim] [MeSO4], the lipase enantioselectivity increased with decreasing hydrogen bond basicity (beta) of the IL when the log E values of lipase in 5% ILs were correlated with IL solvent parameters. With [Bmim] [PF6] as the cosolvent, which has the lowest beta value among all Its examined, the E value was enhanced by a factor of 32. The conversion and ee(p )in 20% [Bmim] [PF6] were 48.0% and 96.9%, respectively. Additionally, the lipase stability in aqueous [Bmim] [PF6] solution was much higher than that in aqueous [Bmim] [MeSO4] solution.</P>
Park, Jae-Keun,Lee, Dong-Hun,Yuk, Seong-Su,Tseren-Ochir, Erdene-Ochir,Kwon, Jung-Hoon,Noh, Jin-Yong,Kim, Byoung-Yoon,Choi, Soo-Won,Kang, Sang-Moo,Lee, Joong-Bok,Park, Seung-Yong,Choi, In-Soo,Song, Cha American Society for Microbiology 2014 CLINICAL AND VACCINE IMMUNOLOGY Vol.21 No.3
<P>In this study, we developed Newcastle disease virus (NDV) virus-like particles (VLPs) expressing NDV fusion (F) protein along with influenza virus matrix 1 (M1) protein using the insect cell expression system. Specific-pathogen-free chickens were immunized with oil emulsion NDV VLP vaccines containing increasing dosages of VLPs (0.4, 2, 10, or 50 μg of VLPs/0.5-ml dose). Three weeks after immunization, the immunogenicity of the NDV VLP vaccines was determined using a commercial enzyme-linked immunosorbent assay (ELISA) kit, and a lethal challenge using a highly virulent NDV strain was performed to evaluate the protective efficacy of the NDV VLP vaccines. NDV VLP vaccines elicited anti-NDV antibodies and provided protection against a lethal challenge in a dose-dependent manner. Although the VLP vaccines containing 0.4 and 2 μg of VLPs failed to achieve high levels of protection, a single immunization with NDV VLP vaccine containing 10 or 50 μg could fully protect chickens from a lethal challenge and greatly reduced challenge virus shedding. Furthermore, we could easily differentiate infected from vaccinated animals (DIVA) using the hemagglutination inhibition (HI) test. These results strongly suggest that utilization of NDV VLP vaccine in poultry species may be a promising strategy for the better control of NDV.</P>
Park, Seong Je,Lee, Ji Eun,Park, Jean Ho,Lee, Nak Kyu,Lyu, Min-Young,Park, Keun,Koo, Myung Sool,Cho, Sung Hwan,Son, Yong,Park, Suk-Hee Hindawi Limited 2018 Advances In Materials Science And Engineering Vol.2018 No.1
<P>Fused deposition modeling (FDM), one of the archetypal 3D printing processes, typically requires support structures matched to printed model parts that principally have undercut or overhung features. Thus, the support removal is an essential postprocessing step after the FDM process. Here, we present an efficient and rapid method to remove the support part of an FDM-manufactured product using the phenomenon of oxidative degradation of hydrogen peroxide. This mechanism was significantly effective on polyvinyl alcohol (PVA), which has been widely used as a support material in the FDM process. Compared to water, hydrogen peroxide provided a two times faster dissolution rate of the PVA material. This could be increased another two times by applying ultrasonication to the solvent. In addition to the rapidness, we confirmed that amount of the support residues removed was enhanced, which was essentially caused by the surface roughness of the FDM-fabricated part. Furthermore, we demonstrated that there was no deterioration with respect to the mechanical properties or shape geometries of the obtained 3D printed parts. Taken together, these results are expected to help enhance the productivity of FDM by reducing the postprocessing time and to allow the removal of complicated and fine support structures, thereby improving the design capability of the FDM technique.</P>
Park, Dongsun,Yang, Goeun,Bae, Dae Kwon,Lee, Sun Hee,Yang, Yun‐,Hui,Kyung, Jangbeen,Kim, Dajeong,Choi, Ehn‐,Kyoung,Choi, Kyung‐,Chul,Kim, Seung U.,Kang, Sung Keun,Ra, Jeong Chan,Kim, Wiley Subscription Services, Inc., A Wiley Company 2013 JOURNAL OF NEUROSCIENCE RESEARCH - Vol.91 No.5
<P><B>Abstract</B></P><P>Brain ageing leads to atrophy and degeneration of the cholinergic nervous system, resulting in profound neurobehavioral and cognitive dysfunction from decreased acetylcholine biosynthesis and reduced secretion of growth and neurotrophic factors. Human adipose tissue‐derived mesenchymal stem cells (ADMSCs) were intravenously (1 × 10<SUP>6</SUP> cells) or intracerebroventricularly (4 × 10<SUP>5</SUP> cells) transplanted into the brains of 18‐month‐old mice once or four times at 2‐week intervals. Transplantation of ADMSCs improved both locomotor activity and cognitive function in the aged animals, in parallel with recovery of acetylcholine levels in brain tissues. Transplanted cells differentiated into neurons and, in part, into astrocytes and produced choline acetyltransferase proteins. Transplantation of ADMSCs restored microtubule‐associated protein 2 in brain tissue and enhanced Trk B expression and the concentrations of brain‐derived neurotrophic factor and nerve growth factor. These results indicate that human ADMSCs differentiate into neural cells in the brain microenvironment and can restore physical and cognitive functions of aged mice not only by increasing acetylcholine synthesis but also by restoring neuronal integrity that may be mediated by growth/neurotrophic factors. © 2013 Wiley Periodicals, Inc.</P>
Park, Young Kyu,Yoon, Hong Man,Kim, Young-Woo,Park, Ji Yeon,Ryu, Keun Won,Lee, Young-Joon,Jeong, Oh,Yoon, Ki Young,Lee, Jun Ho,Lee, Sang Eok,Yu, Wansik,Jeong, Sang-Ho,Kim, Taebong,Kim, Sohee,Nam, Byou Wolters Kluwer Health, Inc. All rights reserved. 2018 Annals of surgery Vol.267 No.4
<P>Conclusions: LADG was feasible for AGC treatment based on the noncompliance rate of D2 lymph node dissection. Subgroups analysis data suggest that further studies are needed for stage III gastric cancer.</P>