정신분열병 환자에서 얼굴 영상의 작동기억 장애 : 기능자기공명영상연구

이창욱,김태석,주라형,박주미,박여진,김종진,전신수,배치운,김정진,이수정,이철,백인호 大韓神經精神醫學會 2005 신경정신의학 Vol.44 No.2

Objectives : Impaired processing of facial information is one of the broad ranges of cognitive deficits seen in patients with Schi-zophrenia. We aimed to elucidate the differences in brain activities involved in the process of facial working memory between schizophrenic patients and healthy comparison subjects. Methods : Twelve patients with schizophrenia were recruited along with twelve demographically matched healthy volunteers as a comparison group. Functional magnetic resonance imaging (fMRI) was used to assess cortical activities during the Perfor-mance of a 2-back working memory paradigm using images of neutral faces as mnemonic content. Rcsults : The patient group performed the tasks with reduced accuracy. Group analysis revealed that the left fusiform gyrus, the right superior frontal gyrus, the bilateral middle frontal gyri/insula, the left middle temporal gyrus, the precuneus, the quadrangular lobules and the vermis of cerebellum showed decreased cortical activities in the patient group. On the other hand, an increased level of activation in the lateral prefrontal cortex and the pahetal lobule was observed from the patient group, all in the right hemisphere. Conulusion : A decreased level of activity in the left fusiform gyrus among the patient group implicates inefficient processing of facial information. An increased level of activation in prefrontal and parietal neural networks from the patient group confirms earlier findings on the impaired working memory of patients with schizophrenia.

Evolutionary Programming for Designing Independent Cells

문치웅,이유경,김장형 濟州大學校工科大學産業技術硏究所 1997 尖端技術硏究所論文集 Vol.8 No.1

본 본문에서는 독립셀 설계를 하나의 0-1 Integer Programming 모델이 개발되었다. 모델은 대안적인 공정계획과 중복설계, 공정시간, 그리고 가용능력등과 같은 현실적인 관련 파라메터들을 고려하여 설계되었다. 그리고 이 모델의 해결을 위해 유전알고리즘에 기초한 진화적 해결방법을 제시하였다. 이 방법은 기존의 방법에 비하여 빠른 시간내에 최적해를 구하였으며, 대규모의 문제에 대하여 효율적으로 적용 가능하였다. In this paper, an evolutionary programming approach is proposed for the designing independent cells in cellular manufacturing with alternative process plans and machine duplication consideration. Several manufacturing parameters such as production volume, machine capacity, processing time, number of cells and cell size are considered in the process. The model is formulated as a 0-1 integer programming and solved using genetic algorithm. It determines the machine cells, part families and process plan for each part simultaneously.

Cd 페라이트의 열적성질에 대한 Mossbauer 효과 연구

홍치유,백승도,이철세 동국대학교 자연과학연구소 1992 자연과학연구 논문집 Vol.12 No.-

이 논문에서는 100-900K의 온도영역에서 CdFe?O?의 Mossbauer 효과를 조사하였다. CdFe?O?의 이성질체 이동치는 온도의 증가에 따라 감소하며, 온도계수는 -5.789×10?㎜/sec·K이다. 사중극자 분열치는 온도에 따른 뚜렷한 변화가 없으며, 흡수선폭은 온도증가에 따라 증가하고, 공명흡수 면적의 온도 의존성을 이용하여 구한 CdFe?O?의 Debye dhsehss 515L이다. Mossbauer effect study is made on CdFe?O? in the temperature range from 100K up to 900K. The isomer shift of the CdFe?O? decrease with the temperature coefficient -5.789×10?㎜/sec·K as the increasing temperature, but we have observed no variation of quadrupole splitting with temperature. The average line width increase slowly with increasing temperature. The Debye temperature of the CdFe?O? calculated by the temperature dependence of the absorption area is 515K.

Three-dimensional evaluation of compositional and structural changes in cycled LiNi_1/3Co_1/3Mn_1/3O₂ by atom probe tomography

Lee, Ji Yeong,Kim, Ji Yoon,Cho, Hae In,Lee, Chi Ho,Kim, Han Sung,Lee, Sang Uck,Prosa, Ty J.,Larson, David J.,Yu, Tae Hwan,Ahn, Jae-Pyoung Elsevier 2018 Journal of Power Sources Vol.379 No.-

<P><B>Abstract</B></P> <P>Accelerated capacity fading of LiNi<SUB>1/3</SUB>Co<SUB>1/3</SUB>Mn<SUB>1/3</SUB>O<SUB>2</SUB> (NCM111) electrode by the chemical migration of lithium (Li) or transition metals (TMs), and surface reconstruction in the surface during electrochemical cycling were evaluated by correlative analysis of atom probe tomography (APT) and transmission electron microscopy (TEM). The cycled NCM111 showed a lack of Li at surface which provides the driving force for long-range Ni migration toward surface. A schematic model for phase transformation and the kinetics of TM migration within the layered structure by density functional theory (DFT) calculations was proposed. This study provides insights into capacity loss and voltage fade upon electrochemical charge-discharge process of NCM111 by measuring the variation of Li composition away from the surface.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Correlative TEM and APT analysis of the chemical migration and phase of cycled NCM. </LI> <LI> APT analysis of three-dimensional surface atomic concentration. </LI> <LI> DFT-based phase transformation model and kinetics of TM migration is proposed. </LI> </UL> </P>

Self-assembled glycol chitosan nanogels containing palmityl-acylated exendin-4 peptide as a long-acting anti-diabetic inhalation system

Lee, Juho,Lee, Changkyu,Kim, Tae Hyung,Lee, Eun Seong,Shin, Beom Soo,Chi, Sang-Cheol,Park, Eun-Seok,Lee, Kang Choon,Youn, Yu Seok Elsevier 2012 Journal of controlled release Vol.161 No.3

<P>Inhalable deoxycholic acid-modified glycol chitosan (DOCA-GC) nanogels containing palmityl acylated exendin-4 (Ex4-C16) were prepared by self-assembly and characterized physicochemically. The lung deposition of DOCA-GC nanogels was monitored using an infrared imaging system, and the hypoglycemia caused by Ex4-C16-loaded DOCA-GC nanogels was evaluated after pulmonary administration in type 2 diabetic db/db mice. The cytotoxicities and lung histologies induced by DOCA-GC nanogels were examined in human lung epithelial cells (A549 and Calu-3) and db/db mice, respectively. Results showed that the DOCA-GC nanogels prepared were spherical and compact and had a diameter of ~220 nm. Although the incorporation of Ex4-C16 (50.97.8%) into DOCA-GC nanogels was significantly lower than that of Ex4 (81.44.9%), the Ex4-C16 release from DOCA-GC nanogels was greatly delayed vs. Ex4. DOCA-GC nanogels were deposited rapidly after pulmonary administration and remained in the lungs for ~72 h. Furthermore, the hypoglycemic duration of inhaled Ex4-C16 nanogels was much greater than that of Ex4 nanogels in db/db mice. Cytotoxicity results of DOCA-GC nanogels were considered acceptable, and the tissue histologies of mouse lungs administered nanogels did not show any significant difference vs. control lungs. The authors believe that Ex4-C16 DOCA-GC nanogels offer a long-acting inhalation delivery system for treating type 2 diabetes.</P>

Bacterial Pathogens of Ventilator Associated Pneumonia in a Tertiary Referral Hospital

Chi, Su Young,Kim, Tae Ok,Park, Chan Woo,Yu, Jin Yeong,Lee, Boram,Lee, Ho Sung,Kim, Yu Il,Lim, Sung Chul,Kwon, Yong Soo The Korean Academy of Tuberculosis and Respiratory 2012 Tuberculosis and Respiratory Diseases Vol.73 No.1

Background: This study evaluates the bacterial pathogens of Ventilator-associated pneumonia (VAP) in a tertiary referral hospital. Methods: A total of 109 bacterial pathogens from 91 adult patients with VAP, who were admitted to the medical intensive care unit from January 2008 to December 2009, were examined. Clinical characteristics, bacterial pathogens, and resistance profiles were analyzed. Results: Staphylococcus aureus (44%) was the most frequently isolated. Acinetobacter baumanii (30%), Pseudomonas aeruginosa (12%), Stenotrophomonas maltophilia (7%), Klebsiella pneumoniae (6%), and Serratia marcescens (2%) were isolated from the transtracheal aspirates or bronchoalveolar lavage in patients with VAP. There was no significant difference of bacterial pathogens between early and late onset VAP. All isolated S. aureus were methicillin resistant S. aureus; the imipenem resistance rate of A. baumanii was 69%. Conclusion: The two most frequent pathogens of VAP were S. aureus and A. baumanii. There were no pathogenic differences between early and late onset VAP.

Effect of Vent Area Ratio on Vent Flow Characteristics and Temperature Distribution in a Compartment Fire with Two Ceiling Vents

Yu Mi Park(Yu Mi Park),Chi Young Lee(Chi Young Lee) 한국화재소방학회 2023 International Journal of Fire Science and Engineer Vol.37 No.1

In this study, the effect of the vent area ratio on vent flow characteristics and temperature distribution in a compartment during a fire in the compartment with two ceiling vents was examined. The area ratio (A1/A2) between ceiling vent 1 (CV1), with a duct height of 0.19 m, and ceiling vent 2 (CV2), with a duct height of 0.05 m, was varied from 0.052 to 0.542, 1, 5.587, and 19.36, and numerical simulation was performed under these conditions. As the A1/A2 ratio increased, the flow pattern changed from unidirectional inflow to bidirectional flow for CV1 and from bidirectional flow to unidirectional inflow for CV2. When the A1/A2 ratio was 0.542, the outflow and inflow mass flow rates for CV1 and CV2 were found to be nearly equal. The outflow and inflow mass flow rates at CV1 were higher than those at CV2 when the A1/A2 ratio was high, while the outflow and inflow mass flow rates at CV2 were higher than those at CV1 when the A1/A2 ratio was low. Furthermore, it was observed that the temperature was lower and the temperature difference between the higher and lower regions in the upper part of the measurement position decreased near the lower part of the vent with a larger area compared to the vent with a smaller area. This was probably because the mixing effect increased near the vent with a larger area due to the occurrence of the active bidirectional flow pattern. When the flow pattern at CV1 was bidirectional, the previous correlation for predicting mass flow rate was examined. It was found that the previous correlation underestimated the mass flow rate of the numerical simulation conducted in this study.

Effects of Duct Height and Fire Location on Fire Phenomena of Enclosure with Two Horizontal Vents Installed on Ceiling

Yu Mi Park(Yu Mi Park),Chi Young Lee(Chi Young Lee) 한국화재소방학회 2022 International Journal of Fire Science and Engineer Vol.36 No.4

The effects of duct height (DH) and fire location (FL) in an enclosure on the mass flow rate and flow pattern of horizontal vent (HV) flow and temperature distribution in the enclosure were investigated through numerical simulations under the condition that two HVs were installed on the ceiling of the enclosure. To evaluate the effect of DH, DHs of HV1 were set to 0.19 m (HV1_DH0.19) and 0.05 m (HV1_DH0.05) under the condition that DH of HV2 was 0.05 m (HV2_DH0.05). The effect of FL was evaluated in three cases where the fire s ources were located in t he c enter of the f loor ( F LC), b elow HV1 ( F L1), a nd below HV2 (FL2). With r espect to the DH effect, the total mass flow rate of the vent flow was slightly higher and temperature was slightly lower in the case of HV1_DH0.19 than that in the case of HV1_DH0.05. However, considering the error bars, the effect of DH in this numerical simulation condition was considered to be insignificant. Furthermore, bidirectional flow patterns appeared in HV1 and HV2 in both DH conditions. Meanwhile, with respect to the FL effect, a bidirectional flow dominated by the mass flow rate of outflow occurred in the HV where the fire source was located, and a unidirectional inflow dominated by the mass flow rate of inflow occurred in the HV where the fire source was not located. The total mass flow rates of FL1 and FL2 conditions were similar, which were higher than those of FLC condition. The temperature was higher in FLC than those in FL1 and FL2. This was due to the small mass flow rate through the HV in the FLC. Meanwhile, an increasing trend of the temperature with the rising measurement height from the floor was observed at most of the temperature measurement points. However, when the fire source was located below HV1 and HV2, as the height from the floor increased, the temperature decreased and the overall temperature was low at the temperature measurement points below the vent where the fire source was not located. This trend was attributed to the occurrence of a strong unidirectional inflow wherein a large volume of low-temperature air flowed into the enclosure from the HV where the fire source was not located.

Synthesis of carbon nanotube fibers using the direct spinning process based on Design of Experiment (DOE)

Lee, Sung-Hyun,Park, Junbeom,Kim, Hye-Rim,Lee, Taeseon,Lee, Jaegeun,Im, Yong-O.,Lee, Cheol-Hun,Cho, Hyunjung,Lee, Hyeseon,Jun, Chi-Hyuck,Ahn, Yu-Chan,Lee, In-Beum,Lee, Kun-Hong Elsevier 2016 Carbon Vol.100 No.-

<P>The optimum synthesis conditions for carbon nanotube (CNT) fibers were investigated using the Design of Experiment (DOE) technique. Direct spinning processes are governed by a variety of experimental factors: the methane flow rate, ferrocene flow rate, sulfur flow rate, hydrogen flow rate, water flow rate, and reaction temperature. The process was optimized in two stages that addressed first the Fractional Factorial Design (FFD) and then the Response Surface Methodology (RSM). Results from each experiment were classified according to a 6-step rating system: nothing(1), black gas(2), dust(3), ribbon or film(4), fiber(5), or continuous fiber(6). In the first step, three major factors (methane, sulfur, temperature) were identified as important among the six experimental factors tested using FFD. The effects of the major factors and the interactions were analyzed through the main effect plot and the interaction plot. In the second step, the experimental conditions were optimized using a model equation derived from Box-Behnken design experiments. Finally, the CNT fibers were continuously synthesized under the optimum conditions. The synthesized CNT fibers mainly consisted of single-walled CNTs (SWCNTs) 1.2 -3.8 nm in diameter. The I-G/I-D ratio of the CNT fibers was 48. This work provides a useful methodology for synthesizing the CNT fibers. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Comparison of Serum Ketone Levels and Cardiometabolic Efficacy of Dapagliflozin versus Sitagliptin among Insulin-Treated Chinese Patients with Type 2 Diabetes Mellitus

Chi-Ho Lee,Mei-Zhen Wu,David Tak-Wai Lui,Darren Shing-Hei Chan,Carol Ho-Yi Fong,Sammy Wing-Ming Shiu,Ying Wong,Alan Chun-Hong Lee,Joanne King-Yan Lam,Yu-Cho Woo,Karen Siu-Ling Lam,Kelvin Kai-Hang Yiu 대한당뇨병학회 2022 Diabetes and Metabolism Journal Vol.46 No.6

Background: Insulin-treated patients with long duration of type 2 diabetes mellitus (T2DM) are at increased risk of ketoacidosis related to sodium-glucose co-transporter 2 inhibitor (SGLT2i). The extent of circulating ketone elevation in these patients remains unknown. We conducted this study to compare the serum ketone response between dapagliflozin, an SGLT2i, and sitagliptin, a dipeptidyl peptidase-4 inhibitor, among insulin-treated T2DM patients.Methods: This was a randomized, open-label, active comparator-controlled study involving 60 insulin-treated T2DM patients. Participants were randomized 1:1 for 24-week of dapagliflozin 10 mg daily or sitagliptin 100 mg daily. Serum β-hydroxybutyrate (BHB) levels were measured at baseline, 12 and 24 weeks after intervention. Comprehensive cardiometabolic assessments were performed with measurements of high-density lipoprotein cholesterol (HDL-C) cholesterol efflux capacity (CEC), vibration-controlled transient elastography and echocardiography.Results: Among these 60 insulin-treated participants (mean age 58.8 years, diabetes duration 18.2 years, glycosylated hemoglobin 8.87%), as compared with sitagliptin, serum BHB levels increased significantly after 24 weeks of dapagliflozin (P=0.045), with a median of 27% increase from baseline. Change in serum BHB levels correlated significantly with change in free fatty acid levels. Despite similar glucose lowering, dapagliflozin led to significant improvements in body weight (P=0.006), waist circumference (P=0.028), HDL-C (P=0.041), CEC (P=0.045), controlled attenuation parameter (P=0.007), and liver stiffness (P=0.022). Average E/e’, an echocardiographic index of left ventricular diastolic dysfunction, was also significantly lower at 24 weeks in participants treated with dapagliflozin (P=0.037).Conclusion: Among insulin-treated T2DM patients with long diabetes duration, compared to sitagliptin, dapagliflozin modestly increased ketone levels and was associated with cardiometabolic benefits.