O-GlcNAcylation of amyloid-β precursor protein at threonine 576 residue regulates trafficking and processing

Chun, Y.S.,Kwon, O.H.,Chung, S. Academic Press 2017 Biochemical and biophysical research communication Vol. No.

The pathological hallmark of Alzheimer's disease (AD) is associated with the accumulation of amyloid-β (Aβ) derived from proteolytic processing of amyloid-β precursor protein (APP). APP undergoes post-translational modification including N- and O-glycosylation. O-GlcNAcylation is a novel type of O-glycosylation, mediated by O-GlcNAc transferase attaching O-β-N-acetylglucosamine (O-GlcNAc) to serine/threonine residues of the target proteins. O-GlcNAc is removed by O-GlcNAcase. We have previously reported that increasing O-GlcNAcylated APP using the O-GlcNAcase inhibitor, PUGNAc, increases its trafficking rate to the plasma membrane and decreases its endocytosis rate, resulting in decreased Aβ production. However, O-GlcNAc modification sites in APP are unknown. In this study, we mutated three predicted O-GlcNAc modification threonine residues of APP into alanines (T291A, T292A, and T576A) and expressed them in HeLa cells. These APP mutants showed reduced O-GlcNAcylation levels, indicating that these sites were endogenously O-GlcNAcylated. Thr 576 was the major O-GlcNAcylation site when cell was treated with PUGNAc. We also showed that the effects of PUGNAc on APP trafficking to the plasma membrane and Aβ production were prevented in the T576A mutant. These results implicate Thr 576 as the major O-GlcNAcylation site in APP and indicate that O-GlcNAcylation of this residue regulates its trafficking and processing. Thus, specific O-GlcNAcylation of APP at Thr 576 may be a novel and promising drug target for AD therapeutics.

Combustion properties of gaseous CH₄/O₂ coaxial jet flames in a single-element combustor

Kim, T.Y.,Choi, S.,Kim, H.K.,Jeung, I.S.,Koo, J.,Kwon, O.C. Butterworths [etc.] ; Elsevier Science Ltd 2016 Fuel Vol.184 No.-

Fundamental combustion properties of gaseous methane (CH<SUB>4</SUB>)/oxygen (O<SUB>2</SUB>) coaxial jet flames in a single-element combustor are experimentally evaluated as a preliminary step for subsequent studies of injection at very low temperature or using liquid O<SUB>2</SUB> for CH<SUB>4</SUB>/O<SUB>2</SUB> bipropellants, recently appearing to be the oncoming liquid bipropellant. A combustion chamber with quartz windows, a single shear coaxial injector and an exhaust nozzle on the downstream of the chamber is considered for the present study. Focusing on the measurements of the ignition and combustion stability limits of the coaxial jet flames in the chamber, flame visualization is also conducted by OH<SUP>*</SUP> chemiluminescence, schlieren imaging and direct imaging. Results show the ignition limits restricted than the combustion stability limits. Flame behaviors are largely classified into two, the stably attached flame and the oscillating, liftoff (near-blowout) flame. Due to cooling effects on the wall of the chamber, stably liftoff flame is not observed. The stability of the flame is greatest at fuel-rich condition (based on the injected amounts of CH<SUB>4</SUB> and O<SUB>2</SUB>). From the flame visualization flame thickness is found to be smaller than the injector lip thickness and insensitive to injection conditions. The laminar-flow behavior near the injector exit due to the strong burning of pure O<SUB>2</SUB> is observed even for high Reynolds numbers (Re). The flame visualization also exhibits the recirculating O<SUB>2</SUB> that enhances burning in the combustor through the reaction with the outer fuel jet. The results of ignition limits, combustion stability limits and flame visualization can be used as a database for researches of modeling the gaseous CH<SUB>4</SUB>/O<SUB>2</SUB> jet flames in the combustion chamber.

CHF₃ / C₂F6 플라즈마에 의한 실리콘 표면 잔류막의 특성

권광호(K.-H. Kwon),박형호(H.-H. Park),이수민(S. M. Lee),강성준(S. J. Kang),권오준(O.-J. Kwon),김보우(B.W. Kim),성영권(Y.-K. Sung) 한국진공학회(ASCT) 1992 Applied Science and Convergence Technology Vol.1 No.1

실리콘을 CHF₃/C₂F_6 가스 플라즈마를 이용하여 식각하면 실리콘위에 탄소, 불소 및 산소로 이루어진 잔류막이 형성된다. 이 잔류막을 XPS로 분석한 결과 탄소는 C-Si, C-Si, C-C/H, C-CF_x(x≤3), C-F, C-F₂, C-F₃ 결합을 하고 있으며, 불소는 F-Si, F-C 및 F-O 결합으로 이루어져 있음을 알았다. 한편 산소는 O-Si 및 O-F 결합으로, 실리콘은 Si-Si, Si-C 및 Si-O 결합상태를 나타낸다. 잔류막의 수직분포 연구를 통하여 Si-O 및 Si-C 결합이 탄소와 불소의 결합층 아래에 존재하고, 잔류막의 표면부에 F-O 결합이 분포함을 알았다. 또한 건식식각 변수가 잔류막 형성에 미치는 영향이 조사되었으며 CHF₃/C₂F_6 가스 유량비, RF power 벚 압력 등이 잔류막의 두께, 조성비 및 잔류막의 결합상태에 영향을 미침을 알 수 있었다. Si surfaces exposed to CHF₃/C₂F_6 gas plasmas in reactive ion etching (RIE) have been characterized by X-ray photoelectron spectroscopy (XPS). CHF₃/C₂F_6 gas plasma exposure of Si surface leads to the deposition of residual film containing carbon and fluorine. The narrow scan spectra of C 1s show various bonding states of carbon as C-Si, C-Si, C-C/H, C-CF_x(x≤3), C-F, C-F₂, and C-F₃. The chemical bonding states of fluorine are described with F-Si, F-C, and F-O. And the oxygen and silicon are also detected. The effects of parameters for reactive ion etching as CHF₃/C₂F_6 gas ratio, RF power, and pressure are investigated.

장기 저장연료의 열안정성 및 연료접촉 고무오링의 수명예측 연구

정근우(K. W. Chung),홍진숙(J. S. Hong),김영운(Y. W. Kim),한정식(J. S. Han),정병훈(B. H. Jeong),권태수(T. S. Kwon),서동욱(D. O. Suh),성민준(M. J. Sung),권영일(Y. I. Kwon) 한국트라이볼로지학회 2018 한국윤활학회지(윤활학회지) Vol.34 No.5

Thermal deterioration of fuel due to long-term storage influences engine performance and causes malfunctions. Fuel stability is usually evaluated via heat resistance and thermal stability during a brief heat shock at high temperature; storage stability in this scenario means that there is very little change in the quality of the fuel during long-term storage. In addition, rubber-based products such as oil seals, O-rings, and rubber hoses can influence the quality of the fuel. When these rubber products are in contact with fuel, they can swell, mechanically weaken, and occasionally crack, thus leaking low molar weight rubber and additives including plasticizer and antioxidant into the fuel to degrade its properties and shorten its useful lifetime. This study determines the thermal stabilities of three kinds of synthetic fuels by evaluating their low temperature kinematic viscosities, chemical composition changes via GC analyses, gross heat of combustion, and color changes. We evaluate the compression set of O-rings by immersing one NBR and two FKM rubber O-rings in the three synthetic fuel samples in airtight containers at variable storage temperatures for six months; from this, we estimate the lifetimes of the O-rings using the Power law model. There were very little changes in the chemical compositions and gross heat of combustion after six months of the experiment. The lifetimes are thus dependent on the materials of the rubber products, and in particular, the FKM O-ring was calculated to have a theoretical lifetime of 200 to 5,700 years. These results indicate that the synthetic fuels maintain their physical properties even after long-term storage at high temperatures, and the FKM O-ring is suitable for long-term sealing of these fuels.

A study of nerve agent model organophosphonate binding with manganese-A₂B-corrole and -A₂B₂-porphyrin systems

Kim, K.,Kim, I.,Maiti, N.,Kwon, S.J.,Bucella, D.,Egorova, O.A.,Lee, Y.S.,Kwak, J.,Churchill, D.G. Pergamon Press 2009 Polyhedron Vol.28 No.12

Herein the synthesis and binding studies of novel trans-A<SUB>2</SUB>B-corrole and trans-A<SUB>2</SUB>B<SUB>2</SUB>-porphyrin derivatives are presented in comparing manganese(III)-organophosphonate (OP) binding (e.g., M<SUP>n+</SUP>←O?PR(OR)<SUB>2</SUB>) capabilities. H<SUB>3</SUB>(PFP-VC) [PFP-VC=5,15-di(pentafluorophenyl)-10-(3-vinylphenyl)corrolate] was synthesized by way of literature procedures and was characterized by a variety of 2-D NMR spectroscopic techniques and single-crystal X-ray diffraction. These compounds represent the first example of 3-vinyl-phenyl-containing meso-substituted corroles or porphyrins. Mn(PFP-VC) (3) was treated separately with (CH<SUB>3</SUB>CH<SUB>2</SUB>O)<SUB>2</SUB>P?O(C<SUB>3</SUB>H<SUB>6</SUB>NMe<SUB>2</SUB>), (C<SUB>4</SUB>H<SUB>9</SUB>O)<SUB>2</SUB>P?O(Me), (C<SUB>2</SUB>H<SUB>5</SUB>O)<SUB>2</SUB>P?O(CH<SUB>2</SUB>COCH<SUB>3</SUB>), (CH<SUB>3</SUB>CH<SUB>2</SUB>O)<SUB>2</SUB>P?O(Me), to give 1:1 adducts, as determined by UV-Vis spectroscopy (Job Plot), giving a red shift; Ph<SUB>3</SUB>P?O, was also found to bind, but very weakly. The trans-A<SUB>2</SUB>B<SUB>2</SUB>-porphyrin analogue Mn(PFP-VP) (4) was also prepared by way of a literature procedure; related binding studies gave 1:1 organophosphonate-Mn(PFP-VP) adducts (Job Plot). A clean blue shift occurred for the Mn-porphyrins at higher organophosphonate loadings (K<SUB>a</SUB> values: 6.7 (0.9)-11.9 (0.4)M<SUP>-1</SUP>). DFT geometry optimizations of O?P(OMe)<SUB>2</SUB>Me binding and formal Mn-O or P-O cleavage products in the unsubstituted neutral Mn-corrolato and -porphyrinato systems with a range of metal-based spin states revealed greatest stability in formal phosphoryl oxygen binding (energies: 11-13kcal/mol) for the Mn-corrole (singlet); the Mn-porphyrin (sextet) was also quite stable.

미국 의학드라마에 나타난 간호이미지와 역할수행 연구

권영애,길민지,김정현,박옥경,서민정,유현정,이민경,정지혜,조양현,천기윤,이자형,정덕유,김성남 이화여자대학교 간호과학대학 2009 이화간호학회지 Vol.- No.43

We tried to inquire the people's views on nursing or nurses, correct the image of nurse and take it as a basis to be applied on nursing education examining the image of nursing on Television drama playing a important role of mass media. 523 nurses of the characters in drama is applied to the analysis object of this study by selecting 3 American medical dramas, Grey's Anatomy, House M.D, E.R from 2005 to 2007. Contents analysis method was used in Data Analysis, which was used in Lim Mi-lim ?Research on contents analysis on image of nursing on television drama?, 7 Items was used after Coders previously modify and compensate it based on research documents of Kalish & Kalisch(1986), Yoon Young(1983), Lee Hye-Ok(1982), Lee Young-Bok, etc in analysis items. Before making the coding, we did pre-test. 6 Coders made of 3teams, 2 Coders are in each team, made the Codings the article on each person by Item seeing the recorded Film. An each team makes coding about 50episodes, total 147episodes for 2weeks. We used double coding and when the results are different between two coders, we decided just one result through mutual agreement. The average of reliability degree was 97.4% which measured the reliability degree by the method of Holsti. The statistic method of Frequency, Percentage was used using EXCEL Program in data processing. The result of research is as follows. 1. The general feature of nurses on the drama is that they are women(92.7%) which is 20 or 30-aged(70.5%). 2. Relative importance of 65.2% nurses in drama is depicted as surrounding characters and most of them was expressed as the character plating surrounding role. 3. The affair attitude of nurses shown on drama is revealed as active(24.5%), autonomous(32%), kind(16.8%), mechanical(23.2%) and adept(28.4%). However, unknown category is the highest in all affairs. 4. The professional activity of nurses was classified with professional/simple affair, The professional activity of nurses was 80% and simple activity of nurses was 22.9%. The professional activity of nurses was classified with personal/assistant affair. The personal activity of nurses was 61.9% and assistant activity of nurses was 15.1%. 5. The place nurses of the drama appears are hospital(97.7%). 6. The appearance feature of nurses is shown on common physique (55.0%), common stature(79.3%), common appearance(76.1%), common dignity(97.5%) and decent (51.1%). 7. The feature of character of nurses depicted on Television drama is neutral in all 11 affairs. We want the following epigraph based on above conclusion. 1. The continuos research intended for mass people is required about how their image of nurse is changed after watching medical drama. 2. The research to construct monitoring mass media system and make plans for developing is required for nurse image being in a triangular position as a professional job.

Effect of Initial Structure for Hot forging of S355NL steel

김상현(S. H. Kim),엄성찬(S. C. Um),김태옥(T. O. Kim),김국주(G. J. Kim),이진모(J. M. Lee),권용남(Y. -N. Kwon) 한국소성가공학회 2012 한국소성가공학회 학술대회 논문집 Vol.2012 No.5

한국식품의 營養成分에 관한 硏究 : 나트륨, 칼륨 함량 측정 Determination of Sodium and Pstassium Concentrations

權赫姬,金達秀,金素姬,權五蘭,金吉女,尹寶奎,崔惠淑 국립보건연구원 1992 국립보건원보 Vol.29 No.2

Synergistic antibacterial effect of curcumin against methicillin-resistant Staphylococcus aureus

Mun, S.H.,Joung, D.K.,Kim, Y.S.,Kang, O.H.,Kim, S.B.,Seo, Y.S.,Kim, Y.C.,Lee, D.S.,Shin, D.W.,Kweon, K.T.,Kwon, D.Y. G. Fischer 2013 Phytomedicine Vol.20 No.8

<P>Methicillin-resistant Staphylococcus aureus (MRSA) are spread among infected patients, with infection rates increasing at an alarming rate. Furthermore, increased resistance to antibiotics has resulted in serious challenges in the treatment of infectious diseases worldwide. Under the selection pressure of exposure to antibiotics, microorganisms evolve to survive against the new conditions imposed by therapy. Therefore, there exists a need to develop alternative natural or combination drug therapies. Curcumin (CCM), a natural polyphenolic flavonoid isolated from the rhizome of a plant, Curcuma longa Linne., has been found to possess many beneficial biological activities. The aim of this study was to investigate the synergistic effect of curcumin and antibiotics as well as to determine the antibacterial activity of CCM against specific MRSA strains. The antibacterial activity of CCM was assessed by the broth microdilution method (by calculating the minimal inhibitory concentration [MIC]), checkerboard dilution test, and time-kill assay. Antimicrobial activity of CCM was observed against all tested strains. The MICs of CCM against 10 strains of S. aureus ranged from 125 to 250 mu g/ml. In the checkerboard test, CCM markedly reduced the MICs of the antibiotics oxacillin (OXI), ampicillin (AMP), ciprofloxacin (CIP), and norfloxacin (NOR) used against MRSA. The time-kill curves showed that a combined CCM and OXI treatment reduced the bacterial counts below the lowest detectable limit after 24 h. This study suggested that CCM reduced the MICs of several antibiotics tested, notably of OXI, AMP, CIP, and NOR, and that CCM in combination with antibiotics could lead to the development of new combination of antibiotics against MRSA infection. (C) 2013 Published by Elsevier GmbH.</P>

저장벽 양자우물구조와 비태칭 패브리 - 페로 공명기 구조에 의한 고성능 2×4 S-SEED Array 구현

권오균(O. K. Kwon),최영완(Y. W. Choi),김광준(K. J. Kim),이일항(E. H. Lee),이상훈(S. H. Lee),원용협(Y. H. Won),유형모(H. M. Yoo) 한국광학회 1994 한국광학회지 Vol.5 No.1

GaAs/Al_(0.04)Ga_(0.96)As 다중양자우물 구조를 이용한 반사형 PIN 다이오우드 S-SEED의 설계에 있어 낮은 동작전압, 높은 포화에너지 및 높은 반사율 on/off 강도비를 얻고자 저장벽 양자우물구조와 비대칭 페브리-페로 공명구조를 결합하였다. 2×4 array를 구성하는 S-SEED들은 역방향 동작전압 5V에서 평균적으로 13 이상의 반사율 on/off 강도비 (CR)와 약 24%의 반사율차 (ΔR) 및 91% 이상의 광쌍안정폭 (Δ)을 나타내었다. 공명구조를 이용함으로서 PIN 다이오우드 진성영역내의 양자우물의 주기수를 줄일 수 있어 외부동작전압 없이도 CR~4.7, R~9.2%, ~22%의 향상된 무전압 광쌍안정 동작특성을 얻었다. We designed and fabricated a 2×4 symmetric self electro-optic effect device array using GaAs/Al_(0.04)Ga_(0.96)As extremely shallow quantum wells grown by a molecular beam epitaxy. By employing ESQW and asymmetric Fabry-Perot cavity structure simultaneously, we improved the performances of S-SEED such as on/off contrast ratio (CR), reflectivity change (ΔR), and optical bistability loop width (Δ). The average values of the elements of the 2×4 S-SEED array were CR~13.1, R~24%, and Δ~91%. It was found that the AFP cavity structure enhances the self-biased optical bistability in ESQW-SEED under no external bias. That is due to the decreased intrisic region thickness in AFP-SEED structures, and which increases the built-in electric fields. The zero-biased S-SEED showed CR of ~4.7, R~9%, and Δ~22%.