수면량과 집중력의 상관관계

김병우,류지근,박우진,박계원,김미정,임지은,백대현,최재덕,최윤호,이가현,이관,김덕수 東國大學校醫學硏究所 2002 東國醫學 Vol.9 No.1

수면, 기억 그리고 학습의 연관성은 실제 매우 복잡하다. 많은 연구에도 불구하고 명확한 연구결과는 아직 없다. 우리는 이 연구에서 평소와는 달리 시험 전날 수면 변화 양상이 집중력에 어느 정도 영향력을 미치는지 알아보고자 하였고, 이를 이용해 효율적인 수면 관리를 할 수 있는 기초자료로 삼고자 하였다. 동국대 의대 본과 1학년생 중 지원자 30명과 본과 2학년생 10명을 대상으로 평상시 상태와 시험 직후 수면이 부족한 상태에서 각각 K-PES TEST를 실시하여 총 8항목에 걸쳐 암기력, 판단력, 단순반응의 변화정도를 검사하였다. 또 설문조사를 병행하여 결과에 영향을 미칠 수 있는 다른 인자들도 파악하였다. 수면량에 대한 부호 숫자 짝짓기(순간 판단력)을 검사한 결과, 인간의 최대 생리학적 기능은 꼭 수면부족에 의해 좌우되는 것은 아니다. 그러나, 수면감소는 피로를 증가시키고, 동기부여를 감소시키나 단, 새로운 사실을 학습하는 데에는 큰 영향을 끼치지 않는다. 즉, 수면부족으로 장시간 깨어있는 것은 정확성과 반응성을 떨어뜨린다. 흡연에 대한 부호 숫자 짝짓기(순간 판단력)을 검사한 결과, 니코틴의 수면에 대한 상호관계는 알려지지 않았고, 인간의 감정이나 의식, 인식에 영향을 주는 것으로 알고있지만, 장기적은 측면에서 흡연이나 알코올은 인식능력과 무관한 것 같다. 카페인에 대한 숫자 외우기(암기력)검사 결과, 카페인은 spacial selective attention에는 특별한 영향을 주지 않지만 지각과정이나 주의 집중에 큰 효과를 주며, 인간의 의식 수행에 긍정적인 효과를 준다. 즉 카페인은 활력, 혼란, 피로상태를 변화시키고 visual analog scales에서 휴식상태에 가까운 양상을 나타낸다. 또 48시간 동안 수면을 취하지 않은 사람에게 카페인은 집중력과 장시간의 좋은 기분을 유지하게 하였다. 그러나 규칙적, 비규칙적으로 먹는 사람간에는 인지수행력의 차이를 보이지 않으며 상용자에서는 상당한 내성이 보인다. 수면패턴에 대한 숫자 더하기(순간 판단력)검사 결과, 집중력은 수면패턴에 의해서도 영향을 받고, 수면패턴이 바뀌게 되면 순간판단력을 저하시킨다. This study was performed to evaluate relationship of sleep and attention, and to control sleep effectively. We conducted a K-PES test of 40 medical students. K-PES contains eight elements, for example, simple response, selective response, color pairing, OddEven discrimination, number addition, number-symbol matching, memory, right-tapping, left tapping. Through these, we tested changes of memory, judgement, simple response. And we conducted a questionnaire survey to exclude bias. Results are as follows. As a results of number-symbol matching test, we know that sleeplessness is not complete responsible for physiologic function for humans. But, decreased sleep increases fatigue and decreases motivation, but no influence on learning new materials. So, long term sleeplessness decreases precision and responsibility. As a results of number-symbol matching test on smoking, a relationship of nicotine and sleep is not certain. A point of view in long term period, smoking and drinking is not related cognition, even if we know that those influence mood, consciousness and cognition. As a results of memory work test on caffeine, caffeine does not influence spacial selective attention, but mainly does perception, attention and consiousness process. Namely caffeine changes energetic activities, chaos, fatigue states and shows resting state in visual analog scales In sleeplessness for 48 hours, caffeine produced attention and good mood for a long time. But, in case of cognitive process no significance shows in regular or irregular diet. Regular diet shows high resistance. As a results of number addition test on sleep patterns, seep patterns influence attention, changes of sleep patterns decrease a moment judgement.

Understanding User Values to Develop the Service Concept Using Network Analysis

Ga Won Kim,Ye Lim Rhie,Hyo Sun Choi,Ji Hyoun Lim,Myung Hwan Yun 대한인간공학회 2012 대한인간공학회 학술대회논문집 Vol.2012 No.5

Objective: The aim of this study is to suggest a way to identify user values in order to develop the service concept based on network analysis. Background: The service design is a complex process that requires understanding the connections between users, providers, and user experience. The core of service design is to discover user values in order to elicit the service concept, which satisfies user needs. Method: The study consists of four main steps; (1) interview data collection, (2) converting raw data into structured data, (3) generating the relation matrix, and (4) network visualization and analysis. Results: 'Joy' was the most important value teens pursuing and, 'beauty' and 'managing relationships' appeared as the key values with high centrality in using the Internet. Conclusion: This study suggested network analysis as a non-hierarchical method for identifying the user value and generating the service concept. Application: The results of the paper might help to interpret the qualitative interview data from the structural perspective.

Energy storage characteristics of {001} oriented Pb(Zr_0.52Ti_0.48)O₃ thin film grown by chemical solution deposition

Lim, Kyung-Won,Peddigari, Mahesh,Annapureddy, Ventateswarlu,Hwang, Geon-Tae,Choi, Jong-Jin,Kim, Ga-Yeon,Yi, Sam Nyung,Ryu, Jungho Elsevier 2018 THIN SOLID FILMS - Vol.660 No.-

<P><B>Abstract</B></P> <P>Capacitors with high energy density and high discharging rate have been attracting attention for electric vehicles and military applications, in which the rapid discharge of large amounts of electric energy is required. Since ferroelectric thin film of perovskite structure has different polarization characteristics according to its crystallographic orientation, the charged energy density can be tailored. In this study, we investigated the effect of the crystallographic orientation of Pb(Zr<SUB>0.52</SUB>Ti<SUB>0.48</SUB>)O<SUB>3</SUB> (PZT) thin films grown by chemical solution deposition on the energy storage capability and discharging rate. The {001} and randomly oriented PZT thin films were prepared and their dielectric and ferroelectric properties, stored energy densities, and discharging rates were characterized. The storage energy density of {001}-oriented film was found to be superior to that of other films, while its efficiency was nearly the same. It is believed that {001} oriented PZT thin film has potential for use in high performance capacitors with large energy density.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Highly {001}-oriented ferroelectric PZT thin film grown by chemical solution deposition </LI> <LI> Energy storage density of the {001}-oriented PZT film reached 8.4 J/cm<SUP>3</SUP> at 80 MV/m </LI> <LI> Discharge time of the {001}-oriented PZT film was 4.1 μs at 27 MV/m </LI> </UL> </P>

Method for the Synthesis of Amine-Functionalized Fullerenes Involving SET-Promoted Photoaddition Reactions of α-Silylamines

Lim, Suk Hyun,Yi, Jinju,Moon, Gyeong Min,Ra, Choon Sup,Nahm, Keepyung,Cho, Dae Won,Kim, Kyungmok,Hyung, Tae Gyung,Yoon, Ung Chan,Lee, Ga Ye,Kim, Soojin,Kim, Jinheung,Mariano, Patrick S. American Chemical Society 2014 Journal of organic chemistry Vol.79 No.15

<P>A novel method for the preparation of structurally diverse fullerene derivatives, which relies on the use of single electron transfer (SET)-promoted photochemical reactions between fullerene C<SUB>60</SUB> and α-trimethylsilylamines, has been developed. Photoirradiation of 10% EtOH–toluene solutions containing C<SUB>60</SUB> and α-silylamines leads to high-yielding, regioselective formation of 1,2-adducts that arise through a pathway in which sequential SET-desilylation occurs to generate α-amino and C<SUB>60</SUB> anion radical pair intermediates, which undergo C–C bond formation. Protonation of generated α-aminofullerene anions gives rise to formation of monoaddition products that possess functionalized α-aminomethyl-substituted 1,2-dihydrofullerene structures. Observations made in this effort show that the use of EtOH in the solvent mixture is critical for efficient photoproduct formation. In contrast to typical thermal and photochemical strategies devised previously for the preparation of fullerene derivatives, the new photochemical approach takes place under mild conditions and does not require the use of excess amounts of substrates. Thus, the method developed in this study could broaden the scope of fullerene chemistry by providing a simple photochemical strategy for large-scale preparation of highly substituted fullerene derivatives. Finally, the α-aminomethyl-substituted 1,2-dihydrofullerene photoadducts are observed to undergo photoinduced fragmentation reactions to produce C<SUB>60</SUB> and the corresponding <I>N</I>-methylamines.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/joceah/2014/joceah.2014.79.issue-15/jo501034t/production/images/medium/jo-2014-01034t_0012.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jo501034t'>ACS Electronic Supporting Info</A></P>

Effects of NICU Nurses´ Self-efficacy, Emotional Intelligence, and Burnout on Performance of Nonpharmacological Pain Interventions in High-Risk Newborns

Ga Eun Jung,Jiyoung Lim,Hye Won Yoon,Kyunghyun Lee 한국간호과학회 2023 한국간호과학회 학술대회 Vol.2023 No.11

Characterization of Polymetal Gate Transistors With Low-Temperature Atomic-Layer-Deposition-Grown Oxide Spacer

Ga-Won Lee,Hi-Duck Lee,Kwan-Yong Lim,Yong Soo Kim,Hong-Sun Yang,Gyu-Seog Cho,Sung-Kye Park,Sung-Joo Hong IEEE 2009 IEEE electron device letters Vol.30 No.2

<P>In this letter, W/WNx/poly-Si gate DRAM transistors with oxide spacers grown by low-temperature atomic layer deposition (ALD) have been fabricated, and the electrical characteristics are analyzed. The low-temperature ALD oxide effectively prevents the oxidation of exposed tungsten, and the fabricated devices show superior electrical properties to those with nitride/oxide spacer. The data retention time is improved by 30%, and the hot-carrier degradation characteristics are also enhanced. The threshold voltage of the fabricated W/WNx/poly-Si gate n-channel transistors with ALD oxide spacer is increased due to the suppression of boron deactivation by hydrogen. In particular, the transconductance of n-channel transistors in core/peripheral circuits was found to be enhanced by less-compressive stress in ALD oxide spacers.</P>

High performance SONOS flash memory with <i>in-situ</i> silicon nanocrystals embedded in silicon nitride charge trapping layer

Lim, Jae-Gab,Yang, Seung-Dong,Yun, Ho-Jin,Jung, Jun-Kyo,Park, Jung-Hyun,Lim, Chan,Cho, Gyu-seok,Park, Seong-gye,Huh, Chul,Lee, Hi-Deok,Lee, Ga-Won Pergamon Press 2018 Solid-state electronics Vol.140 No.-

<P><B>Abstract</B></P> <P>In this paper, SONOS-type flash memory device with highly improved charge-trapping efficiency is suggested by using silicon nanocrystals (Si-NCs) embedded in silicon nitride (SiN<SUB>X</SUB>) charge trapping layer. The Si-NCs were <I>in-situ</I> grown by PECVD without additional post annealing process. The fabricated device shows high program/erase speed and retention property which is suitable for multi-level cell (MLC) application. Excellent performance and reliability for MLC are demonstrated with large memory window of ∼8.5 V and superior retention characteristics of 7% charge loss for 10 years. High resolution transmission electron microscopy image confirms the Si-NC formation and the size is around 1–2 nm which can be verified again in X-ray photoelectron spectroscopy (XPS) where pure Si bonds increase. Besides, XPS analysis implies that more nitrogen atoms make stable bonds at the regular lattice point. Photoluminescence spectra results also illustrate that Si-NCs formation in SiNx is an effective method to form deep trap states.</P>

Anti-Apoptotic Pathway by Specific Wavelength of Irradiation in SNP-Induced SH-SY5Y Neuroblastoma Cell

Won Bong Lim,Sung Ga Lee,Eun Byul Kook,ln Ae Kim,Min A Jung,Ok Joon Kim,Hong Ran Choi 대한구강악안면병리학회 2007 대한구강악안면병리학회지 Vol.31 No.2

The nitric oxide(NO) is a major factor contri buting to t he loss of neurons in ischemic st roke. demyelina t ing diseases, and other neurodegenerative di sorders . But it is known that NO is not function ing as a direct neurotoxin. NO combined with superoxide(02-) by the diffusion-contl'O ll ed reaction, formed a peroxin it ri te anion (ONOO-)‘ which this s pecies has been shown to contribute to oxidative s igna ling and damage. ONOO stimuJates apoptosis in many cell types. whether ONOO acts direct ly as an ox idant 0 1' the induction of apoptosis is because of the radicals derived from ONOO- decompositi on . But. the mecha ni sm by which ONOO- induces apoptosis is un clear although subsequent forrnation 0 1' reactive oxygen s pecies(ROS) has been suggested in a few reports The aim of this study is to investigate the a nti -apoptotic pathway by inhibi tion 0 1' ONOO synthesis t hrough scavenging of ROS us ing s pecific wavelength 0 1' light irradiation . The present study investi gated the a nti -apop totic effect of the specific wavelength 0 1' irradi ation in Sodium Nitroprusside(SNP) t reated SJ-I-SY5Y ceJls, by MTT, DNA fragmentation, and flow cytometric assay and th rough western blot and caspase-3, -9 activity assay for confirmation of caspase pathway. Also. NO reJease and ROS leveJ was measured in order to observe the changes of NO involved in radical by Griess reaction analysis and DCF'-DH. Results showed that the cell viability were r educed by about 50% of control group by SNP treatment, but re covered to about 80% by 590nm irradiation . The apoptotic cells were observed by flow cytomet ry and DNA fra g mentation assay in SNP-treated group‘ but 590nm irradiation led apoptotic feature to be reduced . Released NO a nd ROS level were increased after SNP treatment but ROS level was dec reased in 590nm irradi at ion - treated group, in spite of high NO concentration fo llowing SNP treatment Also. SNP t reatment led cytochrom C release but 590nm irraidiation inhibit it, hence the expression 0 1' caspase-3 and -9 was dec reased sign ificantly‘ These results showed that 590nm irradiation protect neuronal death thl'Ough bl ocking of NO-induced mi tochondri al apoptotic pathway. Also, it suggests that specific wavelength of irradi ation was used for prevent ion from neurodegenerative disordcr progression

Optimization of N:P Ratio of BG 11 Medium for the Phototrophic Lipid Production of Chlorella sp. HS2

Ga Hyeon LEE,Jin-kyu LIM,Won-Kun PARK 한국생물공학회 2022 한국생물공학회 학술대회 Vol.2022 No.9

Effects of Thickness Ratio in Piezoelectric/Elastic Cantilever Structure on the Piezoelectric Energy Harvesting Performance

Ga-Yeon Kim,Mahesh Peddigari,Kyung-Won Lim,Geon-Tae Hwang,Woon-Ha Yoon,HongSoo Choi,이정우,류정호 대한금속·재료학회 2019 ELECTRONIC MATERIALS LETTERS Vol.15 No.1

The energy harvesting by utilizing the piezoelectric eff ect for the conversion of oscillatory mechanical energy to usefulelectrical energy has been promising for self-powered devices. The output power can be controlled by designing the sizeand shape of the constituents of the harvester. This study demonstrates the eff ect of Ti plate (elastic layer) thickness on theresonant frequency, neutral axis position, vibration amplitude and energy harvesting performance of the cantilever structuredpiezoelectric energy harvester (PEH). Here, the each harvester had the same dimensions of piezoelectric layer and the sameproof mass position at the end of the cantilever while it had the diff erent elastic layer thicknesses (70–300 μm). The analysisrevealed that the output power showed the opposite trend in vibration amplitude with varying the elastic layer thickness. Among all of the PEHs, the confi guration with the largest elastic layer thickness (300 μm) exhibited a maximum output powerof 48 μW at 76 Hz under 0.2 g acceleration, despite of the smallest vibration amplitude and the highest resonant frequency. The outcomes suggest that the thickness ratio of the piezoelectric and elastic layers should be optimized to realize the bestharvesting performance.