Using Real-Time Electron Microscopy To Explore the Effects of Transition-Metal Composition on the Local Thermal Stability in Charged Li_<i>x</i>Ni_<i>y</i>Mn_<i>z</i>Co_{1–<i>y</i>–<i>z</i>}O<sub>2</sub

Hwang, Sooyeon,Kim, Seung Min,Bak, Seong-Min,Kim, Se Young,Cho, Byung-Won,Chung, Kyung Yoon,Lee, Jeong Yong,Stach, Eric A.,Chang, Wonyoung American Chemical Society 2015 Chemistry of materials Vol.27 No.11

<P>In this work, we use in situ transmission electron microscopy (TEM) to investigate the thermal decomposition that occurs at the surface of charged LixNiyMnzCo1-y-zO2 (NMC) cathode materials of different composition (with y, z = 0.8, 0.1, and 0.6, 0.2, and 0.4,and 0.3), after they have been charged to their practical upper limit voltage (4.3 V). By heating these materials inside the TEM, we are able to directly characterize near surface changes in both their electronic structure (using electron energy loss spectroscopy) and crystal structure and morphology (using electron diffraction and bright-field imaging). The most Ni-rich material (y, z = 0.8, 0.1) is found to be thermally unstable at significantly lower temperatures than the other compositionsthis is manifested by changes in both the electronic structure and the onset of phase transitions at temperatures as low as 100 degrees C. Electron energy loss spectroscopy indicates that (i) the thermally induced reduction of Ni ions drives these changes, and (ii) this is exacerbated by the presence of an additional redox reaction that occurs at 4.2 V in the y, z = 0.8, 0.1 material. Exploration of individual particles shows that there are substantial variations in the onset temperatures and overall extent of these changes. Of the compositions studied, the composition of y, z = 0.6, 0.2 has the optimal combination of high energy density and reasonable thermal stability. The observations herein demonstrate that real-time electron microscopy provide direct insight into the changes that occur in cathode materials with temperature, allowing optimization of different alloy concentrations to maximize overall performance.</P>

TRANSIENT ISCHEMIA-INDUCED EXPRESSION AND CHANGES OF TYROSINE KINASE A IN THE HIPPOCAMPAL DENTATE GYRUS OF THE GERBIL

HWANG, IN,LEE, HYEON,YOO, KI-YEON,KIM, DAE,KIM, JUNG,KIM, CHANG,LIM, BEONG,KANG, TAE-CHEON,BANG, KYUNG,SEONG, NAK,LEE, HAK,KIM, JONG,WON, MOO Taylor Francis 2006 International journal of neuroscience Vol.116 No.8

<P>The present study examined ischemia-related changes in tyrosine kinase A (trkA) immunoreactivity and its protein content in the dentate gyrus after 5 min of transient forebrain ischemia in gerbils. One day after ischemic insult, cresyl violet-positive polymorphic cells showed ischemic degeneration. The ischemia-induced changes in trkA immunoreactivity were found in the polymorphic layer (PL) and granule cell layer (GCL) of the dentate gyrus. In the sham-operated group, trkA immunoreactivity in the dentate gyrus was very weak. From 30 min after ischemia, trkA immunoreactivity was increased in the dentate gyrus and peaked in the dentate gyrus at 12 h after ischemia-reperfusion. Thereafter, trkA immunoreactivity was decreased time-dependently after ischemia-reperfusion. Four days after ischemic insult, trkA immunoreactivity was similar to that of the sham-operated group. In addition, it was found that ischemia-related changes in trkA protein content were similar to the immunohistochemical changes. These results suggest that the chronological changes of trkA in the dentate gyrus after transient forebrain ischemia may be associated with ischemic damage in polymorphic cells of the dentate gyrus.</P>

Correlating Structural Changes and Gas Evolution during the Thermal Decomposition of Charged Li_<i>x</i>Ni_0.8Co_0.15Al_0.05O₂ Cathode Materials

Bak, Seong-Min,Nam, Kyung-Wan,Chang, Wonyoung,Yu, Xiqian,Hu, Enyuan,Hwang, Sooyeon,Stach, Eric A.,Kim, Kwang-Bum,Chung, Kyung Yoon,Yang, Xiao-Qing American Chemical Society 2013 Chemistry of materials Vol.25 No.3

<P>In this work, we present results from the application of a new in situ technique that combines time-resolved synchrotron X-ray diffraction and mass spectroscopy. We exploit this approach to provide direct correlation between structural changes and the evolution of gas that occurs during the thermal decomposition of (over)charged cathode materials used in lithium-ion batteries. Results from charged Li<SUB><I>x</I></SUB>Ni<SUB>0.8</SUB>Co<SUB>0.15</SUB>Al<SUB>0.05</SUB>O<SUB>2</SUB> cathode materials indicate that the evolution of both O<SUB>2</SUB> and CO<SUB>2</SUB> gases are strongly related to phase transitions that occur during thermal decomposition, specifically from the layered structure (space group <I>R</I>3̅<I>m</I>) to the disordered spinel structure (<I>Fd</I>3̅<I>m</I>), and finally to the rock-salt structure (<I>Fm</I>3̅<I>m</I>). The state of charge also significantly affects both the structural changes and the evolution of oxygen as the temperature increases: the more extensive the charge, the lower the temperature of the phase transitions and the larger the oxygen release. Ex situ X-ray absorption spectroscopy (XAS) and in situ transmission electron microscopy (TEM) are also utilized to investigate the local structural and valence state changes in Ni and Co ions, and to characterize microscopic morphology changes. The combination of these advanced tools provides a unique approach to study fundamental aspects of the dynamic physical and chemical changes that occur during thermal decomposition of charged cathode materials in a systematic way.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2013/cmatex.2013.25.issue-3/cm303096e/production/images/medium/cm-2012-03096e_0014.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm303096e'>ACS Electronic Supporting Info</A></P>

Ischemia-Related Changes in Galanin Expression in the Dentate Hilar Region after Transient Forebrain Ischemia in Gerbils

LEE, Hyeon Yong,HWANG, In Koo,KIM, Dae Ho,KIM, Jung Hwa,KIM, Chang Ho,LIM, Beong Ou,KANG, Tae-Cheon,BANG, Kyung Hwan,SEONG, Nak Sul,LEE, Hak Ju,KIM, Jong Dai,WON, Moo Ho Japanese Association for Laboratory Animal Science 2005 EXPERIMENTAL ANIMALS Vol.54 No.1

<P>Although galanin (GAL) protects hippocampal neurons from ischemic damage, no study has examined ischemia-related changes in endogenous GAL in the hippocampal dentate gyrus. We investigated the chronological changes of GAL, well-known as the potassium channel opener, expression in the dentate gyrus at various times after 5 min of transient forebrain ischemia in gerbils. A few GAL-immunoreactive (IR) neurons were found in the polymorphic layer of the sham-operated group. Three hours after ischemia-reperfusion, the pattern of GAL immunoreactivity was similar to that of the sham-operated group and the number of GAL-IR neurons and immunoreactivity were highest 12 h after ischemic insult. At this time, GAL-IR neurons in the polymorphic layer showed strong GAL immunoreactivity. Thereafter, GAL-IR neurons and immunoreactivity significantly decreased in the dentate hilar region. Four days after ischemic insult, GAL-IR neurons were not detectable. In addition, the results of a Western blot study showed a pattern of GAL expression similar to the immunohistochemical changes. GAL protein content also was highest 12 h after ischemia. In conclusion, the increased expression of endogenous GAL in the dentate gyrus after ischemia is related to response to the ischemic damage.</P>

Characterization of changes in global gene expression in the brain of neuron-specific enolase/human Tau23 transgenic mice in response to overexpression of Tau protein.

Woo, Jong-Min,Park, So Jung,Kang, Ho Il,Kim, Byoung Guk,Shim, Sun Bo,Jee, Seung Wan,Lee, Su Hae,Sin, Ji Soon,Bae, Chang Joon,Jang, Mee Kyung,Cho, Chunghee,Hwang, Dae Youn,Kim, Chuel Kyu D.A. Spandidos 2010 INTERNATIONAL JOURNAL OF MOLECULAR MEDICINE Vol.25 No.5

<P>Tau is a neuronal phosphoprotein responsible for the formation of the neurofibrillary tangles in Alzheimer's disease. To characterize the changes in global gene expression in the brain of transgenic mice that overexpress human Tau23 protein in response to the increase of Tau23 phosphorylation, total RNA extracted from the hippocampus of 12-month-old transgenic and wild-type mice was converted to cDNA, labeled with biotin and hybridized to oligonucleotide microarrays. The microarray results were confirmed by real-time RT-PCR and Western blotting method. It was determined that 43 genes were up-regulated and 8 genes were down-regulated by Tau23 in transgenic mice compared to controls, based on the arbitrary difference in the 2-fold change. Among the up-regulated transcripts, those encoding for transporter and oxidoreductase were dramatically over-represented, followed by those related to regulatory molecule, cytoskeletal protein, signaling molecule, and extracellular matrix protein. Genes encoding for transcription factor, regulatory molecule, miscellaneous function, and chaperone were significantly reduced in the down-regulated group. The major genes in the up-regulated categories included Ecrg4, Folr1, Defb11, Aqp1 and Soctdc1. The major genes in the down-regulated categories were Ncor1, Gpm6a, and Hspd1. These results indicate that the microarray analysis identifies several gene functional groups and individual genes that respond to a sustained increase in Tau23 phosphorylation levels in the brain of transgenic mice. In addition, the results suggest the microarray test is a useful tool for increased understanding of the role of Tau23 protein in regulating neurodegenerative disorders.</P>

유기산의 해리평형에 미치는 치환기 효과와 그의 온도 및 압력의 영향 : (4)수용액중에서 몇가지 이메틸피리딘의 해리상수 (4) Dissociation Constants of some Dimethylpyridines in Aqueous Solution

황정의,정재원,장경희 慶北大學校 自然科學大學 1987 自然科學論文集 Vol.5 No.-

The dissociation constants of 2, 3-, 2, 4-, 2, 5-and 3, 5-dimethylpyridine were measured by conductometric method at various temperatures (15∼40℃) and pressures (1∼2500 bar) in aqueous solution. The shift of dissociation constants of methylptridines from pyridine were explained by the I-effect and cooperative effect of the methyl groups. From the dissociation constants various thermodynamic properties were calculated and discussed the characteristics of the dissociation reactions.

유기산의 해리평형에 미치는 치환기 효과와 그의 온도 및 압력의 영향. : (2) 수용액중에서 몇가지 치환나프톨류의 해리상수 (2) Dissociation Constants of Some Substituted Naphthols in Aqueous Solution

黃正儀,裵俊雄,鄭倧在,鄭在元,張景喜 慶北大學校 物理化學硏究所 1986 硏究論文集 Vol.7 No.-

치환나프톨류(4-Cl-1-Naphthol, 6-Br-2-Naphthol, 8-NH_2-2-Naphthol)의 해리상수를 온도(25∼40℃)와 압력(1∼2000 bar)을 변화시키면서 분광학적 방법으로 측정했다. 이들의 해리상수는 치환기가 들어가므로서 모두 감소했다. 이것은 치환기의 I-효과로서 설명이 가능했으며 또 온도와 압력이 증가하면 해리상수도 증가하였다. 이들 해리상수로부터 반응의 열역학적 성질을 계산하여 반응의 성질을 알아보았다. The dissociation constants of 4-Cl-1-naphthol, 6-Br-2-naphthol, 8-NH_2-2-naphthol in aqueous solution were measured by spectroscopic method in the temperature range from 25 to 40℃ and pressure up to 2000bar. The dissociation constants were decreased as the substituents were inserted in naphthol from 4.4×10 exp(-10) to 5.82×10 exp(-11) as chloride compound and 2.5×10 exp(-10) to 3.44×10 exp(-11) or 4.21×10 exp(-11) as bromine or amino compounds, respectively. This decrease can be explained with the I- or R-effects of substituents. From the dissociation constants various thermodynamic properties were claculated and discussed the characteristics of the dissociation reaction.

원자력 사고 중 핵종의 건·습침적에 따른 농작물 오염 영향

황원태,김은한,서경석,한문희,최용호,이창우 대한방사선 방어학회 2002 방사선방어학회지 Vol.27 No.3

핵종의 지표 침적 모델의 고찰과 함께 방사성물질의 공기중 농도로부터 건침적 뿐 아니라 습침적에 따른 농작물 오염 영향을 분석, 고찰하였다. 이를 위해 방사성물질의 지표 침적량으로부터 농작물의 오염을 평가하는 기존 동적 섭식경로모델을 공기중 농도 또는 지표 침적량으로부터 평가할 수 있도록 개선하였다. 평가결과, 방사성물질의 지표 침적량은 습침적에 의한 영향이 건침적에 의한 영향보다 뚜렷이 높으나, 농작물의 오염정도는 핵종, 강우율 등에 따라 다르게 나타났다. 이러한 현상은 방사성물질의 지표 침적과 농작물에로의 차단중 어느 과정이 농작물 오염에 보다 지배적으로 작용하는가에 기인한다. Combined with deposition model onto the ground of radionuclides, the influence of radioactive contamination to agricultural products was analyzed due to wet deposition as well as dry deposition from radioactive air concentration during a nuclear emergency. The previous dynamic food chain model, in which initial input parameter is only radionuclide concentrations on the ground, was improved for the evaluating of radioactive contamination to agricultural products from either radionuclide concentrations in air or radionuclide concentrations on the ground. As the results, in case of deposition onto the ground, wet deposition was more dominant process than dry deposition. While the contamination levels of agricultural products were dependent on the a variety of factors such as radionuclides and rainfall rate. It means that the contamination levels of agricultural products are determined from which is more dominant process between deposition on the ground and interception onto agricultural plants.

미용사들의 이직욕구에 관한 연구 : 직무스트레스, 근골격계 증상을 중심으로 Focusing on Musculoskeletal Symptoms and Occupational Stress

서은경,문덕환,박명희,김정원,황용식,손병철,김대환,이창희,김휘동,이채언 인제대학교 백병원 2002 仁濟醫學 Vol.23 No.5

Objective : This study was conducted to prepare the fundamental data on desire of job transfer in hairdresser and prevent the health impairment of hairdresser due to occupational stress and musculosketetal symptoms. Methods and Material : The author surveyed the desire of job transfer and muscurlosketetal symptoms and occupational stress with self-reported questionnaire to 105 hairdresser who were working in beautyshop of Busan area and also 121 student in department of cosmestology as control group. Results : The results were as follows: 1. The rates of self reported symptom were 81.0% for shoulder, 72.4% for back, 67.6% for knee, 58.1% for hand in hairdresser, and 79.3% for shoulder, 71.9% for back, 66.9% for neck, 64.5% for hand and knee in student. 2. The rate of musculoskeletal symptom by NIOSH criteria was 36.2% in hairdresser, it was higher than student group(24.8%)(p<0.1). Occupational stress of the groups by occupational stress category was high as decision latitude, skill discretion, psycological job demand, decision authority in order. 3. The results of logistic regression of related varibles with desire of quitting job by logistic regression were statistical bordline significance between desire of quilting and social support(p<0.1). Conclusion : As above results, the author suggest to prepare the preventive program an musculoskeletal symptoms in hairdresser, especially shoulder, and also to control the occupational stress to hairdresser in beauty shop because occupational stress can be a factor of desire of quitting job.

만성정신분열병의 양성 및 음성증상에 대한 Lithium의 항정신병 효과

성상경,장환일,김시균 大韓神經精神醫學會 1989 신경정신의학 Vol.28 No.1

The authors investigated the antipsychotic effect of lithium in 24 chronic refractory schizophrenics with special interest in it's effects on positive and negative symptoms by a method of placebo controlled double-blined cross-over study. Subjects were divided into two sequences: Sequence 1 was Base-Lithium(4wks) -Placebo(4wks) -Lithium(4wks), and Sequence 2 was Base-Placebo(4wks) -Lithium(4wks) -Placebo(4wks). 24 schizophronics, diagnosed according to DSM-Ⅲ-R, were randomly assigned to each sequences so that each sequence had the same number of patients. SAPS(Scale for the assessment of positive symptoms) and SANS(Scale for the assessment of negative symptoms) were used for the assessment of the subjects's mental status. l) 9 of 24 Subjects(31% ) belonged to lithium-responder group : and others to lithium non-responder group. 2) In 9 lithium-responders, statistically significant improvement was noticed in “severity of hallucination as positive" symptom and in - “alogia” as negative symptom. 3) “Clothing & appearnce" among positive symptoms and “inappropriate affect" and “subjective complaint of inattentiveness" among negative symptoms changed statistically significantly in all subjects(N -24) All global ratings did not change significantly after lithium treatment.