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Functional magnetic resonance imaging of cerebellar activation and lateralization during verbal and visuospatial tasks

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Neural Regeneration Research 2010年第3期5卷 226-231页

作者： Mi-Hyun choi Su-Jeong Lee Jae-Woong Yang Jin-Seung choi Hyung-Sik Kim Jeong-Han Yi Gye-Rae Tack Soon-Cheol Chung byung-Chan min Se-Jin Park Jong-Rak Park Jae-Hoon Jun Department of Biomedical Engineering Research Institute of Biomedical Engineering College of Biomedical & Health Science Konkuk University Department of Industrial & Management Engineering Hanbat National University Division of Technology Services National Center for Standard Reference Data Korea Research Institute of Standards and Science Department of Photonic Engineering Chosun University

BACKGROUND： Previous studies have analyzed cerebral activation and lateralization of cognitive functions, as well as cerebellar function with reference to high-level cognitive processing. However, there has been very little research on systematization and diversification. In particular, there are no reports on cerebellar lateralization, although reliable results have been reported on cerebral lateralization. OBJECTIVE： This study analyzed cerebellar activation and lateralization in relation to verbal and visuospatial tasks using functional magnetic resonance imaging （fMRI）. DESIGN, TIME AND SETTING： A block design for fMRI observation was performed at the fMRI Laboratory, Brain Science Research Center, Korea Advanced Institute of Science and Technology from May 2006 to September 2008. PARTICIPANTS： Sixteen healthy, male, college students, aged （23.3 ± 0.5） years, and 16 healthy, male, college students, aged （21.5 ± 2.3） years, participated in the study, respectively. METHODS： Verbal and visuospatial tasks were presented while functional brain images were acquired using a 3T fMRI system. Verbal analogy testing required the subject to select the word with the same relationship as one of the given words. Verbal antonym testing required the subject to select the word with a different meaning among four words. Visuospatial tasks involved selecting a shape that corresponded to a given figure with four examples, as well as selecting a development figure of a diagram. MAIN OUTCOME MEASURES： Changes in cerebellar activation and lateralization between two cognition tasks. RESULTS： Bilateral hemisphere Iobules VI and IX, right hemisphere Iobule VIII, bilateral hemisphere Iobules Crus I, and vermis Iobule IV, V, and Vl were closely related to verbal tasks in comparison to visuospatial tasks. Conversely, bilateral hemisphere Iobules IV and V, as well as the right hemisphere Iobule VI, were closely related to visuospatial tasks compared to verbal tasks. There was no great differe

关键词： cerebellum lateralization functional magnetic resonance imaging verbal and visuospatial tasks neuroimaging neural regeneration

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Long-term outcomes of penetrating keratoplasty in keratoconus: analysis of the factors associated with final visual acuities

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International Journal of Ophthalmology(English edition) 2014年第3期7卷 517-521页

作者： Jin A choi min A Lee Man-Soo Kim Department of Ophthalmology St. Vincent's HospitalCollege of Medicine the Catholic University of Korea #93 Jungbudae-ro Paldal-gu Suwon-si Kyunggi-do 442-723Korea Department of Ophthalmology and Visual Science Seoul St.Mary's Hospital College of Medicine Catholic University of Korea #505 Banpo-dong Seocho-ku Seoul 137-701 Korea

AIM:To investigate the long-term results of penetrating keratoplasty(PK)in patients with keratoconus(KC)and to evaluate factors that might influence the final visual ***:We retrospectively reviewed the data of all patients with clinical KC who had undergone PK by a single corneal surgeon in a single center from May 1980to December *** age of the patients,preoperative best-corrected visual acuity(BCVA),corneal thickness,death to preservation time,and preservation to transplantation time were ***,postoperative complications such as graft rejection,development of glaucoma and specular microscopy were checked during the ***:Sixty-nineeyesfrom69patientswerefinally *** follow-up period was 8.64±*** rejection occurred in 4 eyes of 69 cases(5.8%),and the time to graft rejection was 2.1±1.3y.A Kaplan-Meier survival analysis showed that the estimated cumulative probability of graft rejection at 6,13,and 17y after PK were 95.6%,90.0%,and 78.8%,*** we evaluated factors that might influence final BCVA in eyes,no disparity donor-host trephine size(same graft size)as well as higher spherical equivalent,and average Kvalue were associated with higher final BCVA.(P=0.006,0.051,0.092,and 0.021 in eyes with follow-up<8y;P=0.068,0.065,and 0.030 in eyes with follow-up≥8y,respectively).CONCLUSION:The long-term results of PK in patients with KC were favorable with a high percentage of good *** myopic change and low average K-reading,as well as a surgical technique using the same size donor-recipient button may provide better visual outcomes particularly in patients with KC.

关键词： keratoconus penetrating keratoplasty visual outcome

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Identification of Aristolactam Derivatives That Act as Inhibitors of Human Immunodeficiency Virus Type 1 Infection and Replication by Targeting Tat-Mediated Viral Transcription

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Virologica Sinica 2021年第2期36卷 254-263页

作者： Young Hyun Shin Chul min Park Hong Gi Kim Dong-Eun Kim min Suk choi Jeong-ah Kim Byeong-Sun choi Cheol-Hee Yoon Division of Viral Disease Research Center for Infectious Disease ResearchKorea National Institute of HealthHeungdeok-guCheongju-siShungbuk 28159Republic of Korea Center for Convergent Research of Emerging Virus Infection Korea Research Institute of Chemical TechnologyYuseong-guDaejeon 34114Republic of Korea

Despite the success of antiretroviral therapy(ART),efforts to develop new classes of antiviral agents have been hampered by the emergence of drug ***-indole-bearing aristolactams are compounds that have been isolated from various plants species and which show several clinically relevant effects,including anti-inflammatory,antiplatelet,and antimycobacterial ***,the effect of these compounds on human immunodeficiency virus type 1(HIV-1)infection has not yet been *** this study,we discovered an aristolactam derivative bearing dibenzo[cd,f]indol-4(5 H)-one that had a potent anti-HIV-1 effect.A structure-activity relationship(SAR)study using nine synthetic derivatives of aristolactam identified the differing effects of residue substitutions on the inhibition of HIV-1 infection and cell *** the compounds tested,1,2,8,9-tetramethoxy-5-(2-(piperidin-1-yl)ethyl)-dibenzo[cd,f]indol-4(5 H)-one(Compound 2)exhibited the most potent activity by inhibiting HIV-1 infection with a half-maximal inhibitory concentration(IC50)of 1.03 lmol/L and a half-maximal cytotoxic concentration(CC50)of 16.91 lmol/L(selectivity index,16.45).The inhibitory effect of the compounds on HIV-1 infection was linked to inhibition of the viral replication ***-of-action studies showed that the aristolactam derivatives did not affect reverse transcription or integration;instead,they specifically inhibited Tat-mediated viral *** together,these findings show that several aristolactam derivatives impaired HIV-1 infection by inhibiting the activity of Tat-mediated viral transcription,and suggest that these derivatives could be antiviral drug candidates.

关键词： Human immunodeficiency virus type 1(HIV-1) Aristolactam Antiviral activity HIV-1 transcription

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State-of-the-art preoperative staging of gastric cancer by MDCT and magnetic resonance imaging

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World Journal of Gastroenterology 2014年第16期20卷 4546-4557页

作者： Joon-Il choi Ijin Joo Jeong min Lee Department of Radiology Seoul St. Mary’s HospitalCollege of MedicineThe Catholic University of KoreaSeoul 137-701South Korea Department of Radiology and Institute of Radiation Medicine Clinical Research InstituteSeoul National University HospitalSeoul National University College of MedicineSeoul 110-744South Korea

Gastric cancer is one of the most common and fatal cancers. The importance of accurate staging for gastric cancer has become more critical due to the recent introduction of less invasive treatment options, such as endoscopic mucosal resection or laparoscopic surgery. The tumor-node-metastasis staging system is the generally accepted staging system for predicting the prognosis of patients with gastric cancer. Multidetector row computed tomography (MDCT) is a widely accepted imaging modality for the preoperative staging of gastric cancer that can simultaneously assess locoregional staging, including the gastric mass, regional lymph nodes, and distant metastasis. The diagnostic performance of MDCT for T- and N-staging has been improved by the technical development of isotropic imaging and 3D reformation. Although magnetic resonance imaging (MRI) was not previously used to evaluate gastric cancer due to the modality’s limitations, the development of high-speed sequences has made MRI a feasible tool for the staging of gastric cancer.

关键词： Gastric cancer Multidetector row computed tomography Magnetic resonance imaging Preoperative staging The tumor-node-metastasis staging

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Comparison of litterfall production in three forest types in Jeju Island, South Korea

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Journal of Forestry Research 2020年第3期31卷 945-952页

作者： Ji Young An Si Ho Han Woo Bin Youn Sang Ick Lee Afroja Rahman Huong Thi Thuy Dao Jeong min Seo Aung Aung Hyung-Soon choi Hwa Ja Hyun byung Bae Park Department of Natural Resources Kyoto UniversityKyoto 606-8502Japan Department of Environment and Forest Resources Chungnam National UniversityDaejeon 34134Republic of Korea Forest Environment Conservation Division Korea Forest ServiceDaejeon 35208Republic of Korea Forest Conservation Department National Institute of Forest ScienceSeoul 02455Republic of Korea Warm Temperate and Subtropical Forest Research Center National Institute of Forest ScienceSeogwipo 63582Republic of Korea

Litterfall, which is influenced by physical and biological factors, is a major pathway for carbon and nutrient cycling in forest ecosystems. The purpose of this study was to investigate monthly litterfall production in three forests in Jeju Island differentiated by forest composition and precipitation: Cheongsu(Quercus glauca as the dominant species;low precipitation), Seonheulb(Q. glauca as the dominant species;high precipitation), and Seonheulm(Q. glauca and Pinus thunbergii as the dominant species;high precipitation). Litterfall was collected monthly from April to December 2015 and divided into leaf litter, twig, bark, seeds, and unidentified *** patterns of litterfall production varied across stands according to their species composition. However,the amount of leaf litterfall and total litterfall were comparable among stands, ranging from 362 to 375 g m-2 for leaf litter and 524 g m-2 to 580 g m-2 for total *** leaf litter in May was the highest in all stands, while needle litter was the highest in December in *** twig litterfall in July may be attributable to high rainfall with strong winds and storms during the rainy season. Although forest type and climate factor had no influence on litterfall amounts in this study, the pattern of litterfall production was species dependent, suggesting diverse effects on carbon and nutrient cycling in these forests.

关键词： Coniferous forest Evergreen broadleaved forest Gotjawal Leaf litter Precipitation Temperature

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Feedback Control of an Achiral Robotic Microswimmer

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Journal of Bionic Engineering 2017年第2期14卷 245-259页

作者： U Kei Cheang Hoyeon Kim Dejan Milutinovic Jongeun choi min Jun Kim Department of Mechanical Engineering and Mechanics Drexel University Philadelphia PA 19104 USA Department of Mechanical Engineering Southern Methodist University Dallas TX75275 USA Department of Computer Engineering University of California Santa Cruz Santa Cruz California 95064 USA School of Mechanical Engineering Yonsei University Seoul South Korea

Magnetic microswimmers are useful for navigating and performing tasks at small scales. To demonstrate effective control over such microswimmers, we implemented feedback control of the three-bead achiral microswimmers in both simulation and experiment. The achiral microswimmers with the ability to swim in bulk fluid are controlled wirelessly using magnetic fields generated from electromagnetic coils. The achirality of the microswimmers introduces unknown handedness resulting in uncertainty in swimming direction. We use a combination of rotating and static magnetic fields generated from an approximate Helmholtz coil system to overcome such uncertainty. There are also movement uncertainties due to environmental factors such as unsteady flow conditions. A kinematic model based feedback controller was created based on data fitting of experimental data. However, the controller was unable to yield satisfactory performance due to uncertainties from environmental factors; i.e., the time to reach target pose under adverse flow condition is too long. Following the implementation of an integral controller to control the microswimmers＇ swimming velocity, the mieroswimmers were able to reach the target in roughly half the time. Through simulation and experiments, we show that the feedback control law can move an achiral microswimmer from any initial conditions to a target pose.

关键词： microrobotics magnetic control low Reynold number chirality feedback control

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Microstructure of fast tool servo machining on copper alloy

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中国有色金属学会会刊：英文版 2012年第S3期22卷 820-824页

作者： Hong LU Soo-chang choi Sang-min LEE Deug-woo LEE Department of Nano Fusion Technology Pusan National University Korea Institute of Machinery & Materials Department of Nano Mechatronics Engineering Pusan National University

The development of the fast tool servo (FTS) for precision machining was *** micron machining performance of a piezoelectric-assisted FTS on copper alloy was *** results indicate that the quality of the microstructure depends mainly on two important factors:the cutting speed (or spindle speed) and the driving frequency of the *** excessive driving frequency increases the formation of *** effect of the clearance angle of the diamond tool on the microstructure machining precision was also investigated.

关键词： fast tool servo microstructure piezoelectric diamond machining copper alloy

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Free Energy Level Correction by Monte Carlo Resampling with Weighted Histogram Analysis Method

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Chinese Journal of Chemical Physics 2020年第2期33卷 183-195,I0003,I0010-I0017页

作者： Seyoung Chung Sun Mi choi Wook Lee Kwang Hyun Cho Young min Rhee Department of Chemistry Pohang University of Science and TechnologyPohang 37673Korea Department of Chemistry Korea Advanced Institute of Science and TechnologyDaejeon 34141Korea

Free energy calculations may provide vital information for studying various chemical and biological *** mechanical methods are required to accurately describe interaction energies,but their computations are often too demanding for conformational *** a remedy,level correction schemes that allow calculating high level free energies based on conformations from lower level simulations have been ***,we present a variation of a Monte Carlo(MC)resampling approach in relation to the weighted histogram analysis method(WHAM).We show that our scheme can generate free energy surfaces that can practically converge to the exact one with sufficient sampling,and that it treats cases with insufficient sampling in a more stable manner than the conventional WHAM-based level correction *** can also provide a guide for checking the uncertainty of the levelcorrected surface and a well-defined criterion for deciding the extent of smoothing on the free energy surface for its visual *** demonstrate these aspects by obtaining the free energy maps associated with the alanine dipeptide and proton transfer network of the KillerRed protein in explicit water,and exemplify that the MC resampled WHAM scheme can be a practical tool for producing free energy surfaces of realistic systems.

关键词： Free energy level correction Weighted histogram analysis method Monte Carlo resampling

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Series resistance influence on performance of waveguide-type germanium photodetectors on silicon

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Chinese Optics Letters 2017年第10期15卷 15-19页

作者： Jeong-min Lee minkyu Kim and Woo-Young choi Department of Electrical and Electronic Engineering Yonsei University Seoul 120-749 South Korea

We investigate influences of series resistances on the performance of 1.55 μm waveguide-type germanium photodetectors（Ge-PDs） on a silicon-on-insulator substrate. The current-voltage characteristics, responsivities,saturation photo-current characteristics, electrical reflection coefficients, and photodetection frequency responses of Ge-PDs, having different series resistances, are measured, and their equivalent circuit models are established. By analyzing the resulting circuit model parameters, we determine how much Ge-PD series resistances influence Ge-PD saturation photo-currents and photodetection bandwidth. These results should be of great use for optimization of Ge-PD fabrication processes and device parameters for target applications.

关键词： Si Series resistance influence on performance of waveguide-type germanium photodetectors on silicon PD Figure

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Role of computed tomographic colonoscopy of postoperative surveillance in patient with gastric cancer

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World Journal of Gastroenterology 2007年第11期13卷 1646-1651页

作者： Dae Won Jun Oh Young Lee Hyun Chul Lim Sung Joon Kwon Hang Lak Lee byung Chul Yoon Ho Soon choi Joon Soo Hahm min Ho Lee Dong Hoo Lee Department of Internal Medicine Hanyang University College of Medicine Seoul Korea Department of Radiology Hanyang University College of Medicine Seoul Korea Department of General Surgery Hanyang University College of Medicine Seoul Korea

AIM： TO examine the diagnostic yield of colorectal neoplasia at computed tomographic colonoscopy （CTC） as well as the feasibility of contrast enhanced CTC in patients with gastric cancer. METHODS： To examine the incidence of colon polyp we selected postoperative 188 gastric cancer patients, which we refer to as the ‘colon polyp survey group’. To examine the feasibility of CTC for early detection of colon cancer or advanced colon adenoma, we selected 47 gastric cancer patients （M：F 29：18, mean age 53.8 years）, which we call the ‘CT colonoscopy group’. All the 47 patients underwent successive CTC and colonoscopy on the same day. RESULTS： Totally 109 colon polyps were observed from 59 out of 188 gastric cancer patients, the inddence rate of colon polyps in gastric cancer patients being 31.4%. The sensitivity of CTC in detecting individuals with at least 1 lesion of any size was 57.1%, the specificity was 72.7%, the positive predictive value was 47.1%, and the negative predictive value was 71.9%. When the cutoff size was decreased to 6 mm, the sensitivity and specificity were 80.0% and 92.9%, respectively, with positive and negative predictive values of 57.1% and 97.5%, respectively. Only one patient was classified as false negative by virtual colonoscopy. CONCLUSION： The diagnostic yield of colorectal polyp was 31.4% in patients with gastric cancer, and contrast enhanced CTC is an acceptable tool for the detection of synchronous colorectal advanced adenoma and postoperative surveillance of gastric cancer patients.

关键词： Stomach cancer Colon cancer Computed tomocjraphic colonoscopy

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