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.

광탄성실험 Hybrid 법에 의한 일정한 변형율을 받는 O-Ring 의 응력해석

권오성(O-Sung Kwon),황재석(Jai-Sug Hawong),남정환(Jeong-Hwan Nam),한송령(Song-Ling Han),박성한(Sung-Han Park) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11

In this research, stresses of O-ring with uniform deformation ratio in upper and lower direction are analyzed by photoelastic experimental hybrid method. The O-ring is made from rubber and is used to sealing of the high pressure vessel. The compressive deformation ratios of O-ring are 10% and 20%. Stress components (σ<SUB>xx</SUB>, σ<SUB>yy</SUB>, τ<SUB>xy</SUB>) of O-ring uniform ratios obtained from the photoelastic experimental hybrid method are almost identical to those from Hertz’s theory. Therefore, stress freezing method and photoelastic experimental hybrid method are effective applied to the stress analysis of O-ring made from rubber and with uniform ratios. The loading device developed in this research is used to produce the uniform deformation ratio of O-ring and as loading device of stress freezing. Stress distributions results from the upper contact surface of O-ring are almost identical to those from the lower contact surface of O-ring without regard to squeeze deformation ratio.

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.

Excluded vertex-minors for graphs of linear rank-width at most k

Jeong, J.,Kwon, O.j.,Oum, S.i. Academic Press 2014 European journal of combinatorics : Journal europ& Vol.41 No.-

Linear rank-width is a graph width parameter, which is a variation of rank-width by restricting its tree to a caterpillar. As a corollary of known theorems, for each k, there is a finite obstruction set O<SUB>k</SUB> of graphs such that a graph G has linear rank-width at most k if and only if no vertex-minor of G is isomorphic to a graph in O<SUB>k</SUB>. However, no attempts have been made to bound the number of graphs in O<SUB>k</SUB> for k≥2. We show that for each k, there are at least 2<SUP>Ω(3^k)</SUP> pairwise locally non-equivalent graphs in O<SUB>k</SUB>, and therefore the number of graphs in O<SUB>k</SUB> is at least double exponential. To prove this theorem, it is necessary to characterize when two graphs in O<SUB>k</SUB> are locally equivalent. A graph is a block graph if all of its blocks are complete graphs. We prove that if two block graphs without simplicial vertices of degree at least 2 are locally equivalent, then they are isomorphic. This not only is useful for our theorem but also implies a theorem of Bouchet (1988) stating that if two trees are locally equivalent, then they are isomorphic.

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.

비·부비동 모형에서 전비공 및 비인강폐쇄 정도에 따른 상악동 환기의 변화

권오성,김기식 東國大學校醫學硏究所 2003 東國醫學 Vol.10 No.2

목적 : 부비동염은 부비동 점막의 염증성 질환으로 상기도에 발생하는 가장 흔한 질환이다. 부비동의 정상적인 생리는 부비동의 자연개구부를 통한 환기, 점액섬모운동, 점막을 통한 산소교환, 점막내의 혈액공급등이 적절하게 유지되는 것을 말하며, 이러한 정상생리를 방해하는 다양한 원인으로 부비동염이 발생한다. 부비동의 환기는 자연개구부의 크기, 비강의 크기와 모양, 비강내 기류, 부비동의 크기, 점막의 병리적 상태등과 같은 다양한 인자에 의해 영향을 받는다. 본 연구는 전산화단층촬영 영상을 토대로 실물크기의 비부비동 모형을 제작하여, 모형의 전비공 및 비인강의 폐쇄정토에 따른 상악동의 환기정도가 어떤 변화를 보이는지 알아보고자 한다. 재료 및 방법 : 비과적 증상이 없는 건강한 성인남자로부터 얻은 전산화단충촬영 영상으로 비부비동 모형을 제작하였다. 모형의 좌측 상악동으로 100% 산소를 주입한 후 비인강에 연결된 관을 통해 지원자가 입으로 호흡하는 동안 좌측 상악동의 산소농도를 측정하였다. 상악동내 산소농도가 95%에서 25%로 감소하기 위한 호흡횟수를 측정하였고 이를 30회 반복하여 평균호흡횟수(RN95-25)를 구하였다. 고무찰흙을 이용해서 전비공 폐쇄 및 비인강 폐쇄 모형을 만들어 각각 같은 방법으로 호흡횟수를 측정하여 정상과 비교하였다. 결과 : 정상 모형에서 평균 호흡횟수(RN95-25)는 27.50±2.36회 이었다. 동측 전비공 폐쇄 모형에서는20%, 40%, 60%의 폐쇄시 각각 16.30±1.53, 11.47±1.20, 7.40±0.89회로 유의한 호흡횟수의 감소를 보여(P<0.05) 동측 상악동의 환기정도가 정상에 비해 증가함을 알 수 있었다. 비인강 폐쇄 모형에서는 20%, 40%, 60% 폐쇄시 각각 19.16±1.93, 20.87±1.67, 21.51±1.72회로 감소하였으나 80% 폐쇄시에는 35.77±1.78회로 유의한(P<0.05) 호흡횟수의 증가를 나타내어 일정수준 이하의 폐쇄에서는 환기정도가 증가하였으나 그 이상에서는 감소함을 알수있었다. 결론 : 전비공 폐쇄시 상악동 환기증가는 비강내의 기류분포의 큰 저항 없이 비저항을 크게 증가시켰기 때문이라고 생각된다. 반면 비인강폐쇄로 인한 비저항 증가는 일정 수준까지는 기류 증가로 인한 환기증가를 가져오지만, 그 이상에서는 중비도를 통한 기류를 감소시켜 상악동 환기를 저하시키는 것으로 사료된다. 향후 동일한 모형으로 비강내 기류및 압력을 함께 측정하는 실험을 통해 비강내 구조와 상악동 환기에 대한 공기역학적 관계를 보다 잘 이해할 수 있을 것으로 생각된다. Objectives: The sinusitis is the mucosal inflammation of sinus which is most common in upper respiratory tract. Decreased ventilation of sinus ostium is probably the most important in the development of sinus and these sinus ventilation are deranged by the dysfunction of the physiologic orders affected by the multiple causes; the size of natural ostiums, contour and air streams of nasopharynx, the size and pathologic conditions in the sinus. The connection between structural alteration in naso-nasopharyngeal cavity and sinus ostial vetilation is not completley understood. To investigate this problem, experiments with delicate human sinus model have been perfomed. Material and method: The sinonasal model was constructed firm CT of a healthy young man. The oxygen saturation in the left maxillary sinus was investigated while a volunteer breaths through the corrugated tube connected to the nasopharynx of the model. We studied to get the numbers of respiration(RN95-25) by watching O_(2) saturation of the maxillary sinus from 95% to 25 % ( volunteer repeat 30 times to have O_(2) saturation down to minimize the error). Results: Increased sinus ventilation was recognized by the increasead nasal resistance while the ipsilateral anterior nare was obstructed(p<0.05). In nasopharyngeal obstruction model, we noticed respiratory rate was decreasead among the 20%, 40% and 60%, but increased at 80% in the nasopharyngeal obtruction model(p<0.05). Therefore the ventilation was increased up to the certain level of the nasopharyngeal obstruction, to follow by decreasing after that level. Conclusion: We observed the nasal resistance increased maxillary sinus ventilation without resistant stream pattern in the nasal cavity when anterior nare obstructed. To the contrary the nasopharyngeal resistance was increased at the beginning and then decreased by the increased air streams through the middle meatus after certain level. The results from our studies could be useful to understand the relations between structural alteration on naso-nasopharyngeal cavity and ventilation of the sinuses.

Kafka 作品에 나타난 法(Recht)과 權力(Macht) 硏究

권오상 제주대학교 인문과학연구소 2002 인문학연구 Vol.9 No.-

Der Dritte, der nach geltendem Recht als Richter entscheidet, fehlt. Das heißt nur, daß er selbst zur Partei geho¨rt, d. h. einer dritten Partei zugeho¨rt oder parteilich sich einer der zwei bestehenden Parteien anschließt. Entsprechend treten in Kafkas Werken - z.B. im Urteil oder im Prozeß - immer nur zwei Parteien auf, sind Richter Ankla¨ger eins. Auch ein regulativer Rechts-Kodex scheint nur als Phantasma zu existeren, jedenfalls als etwas dem Kampf der Parteien, Machtbeziehungen Sekunda¨res. Das Urteil erfolgt also dezisionistisch. Das Gesetz ist statt Voraussetzung Resultat des Rechtsprozesses. Keineswegs hat nach Foucault das Gesetz dle Hegelsche Form der im Allgemeinen aufgehobenen Dialektik gegenseitiger Anerkennung, seine Agenten formieren nicht den allgemeinen Stand, Polizei und Rechtsaufsicht bilden nicht die sichrnde Macht des Allgemeienen. Gesetze und Nomen sind vielmehr Funktionen der Macht. Der U¨bergriff des Milita¨rs entlarvt die Rechts-Illusionen des Zivilisten. Mithin geht es nicht allein um politische Gewalten, wie sie sich hinter traditionalen, charismatischen und legalen Herrschaftsfomen verbergen mo¨gen, sondern um all jene Ma¨chte, die im Sozialen, o¨konomischen, privaten und intimen Bereich auf den Arglosen hereinbrechen, der auf den Schutz vertraut. Was hinter dem Gesetz als ultima ratio und als seine fundamentale Begru¨ndung steht, dle Gewalt, la¨ßt Kafka nackt als solche hervortreten. Hinter dem Gesetz steht immer das Schwert. Fu¨r Kafka steht auch hinter den modernen Sozialtechniken noch immer das Schwert. Ohne Eingriff der Gewaltinstanz erweist sich dle zivile, bu¨rgerliche Ordnung als Machtverha¨ltnis. Der Tausch wird ausser Kraft gesetzt, wenn der eine dem anderen gegenu¨ber nicht ma¨chtig genug ist, ihn zu erzwingen. Auch das zivile Leben erweist sich als von Machtbeziehungen und Kra¨fteverha¨ltnissen bestimmt. Die Instanz der Macht scheint sich nur auf der Basis der Unsicherheit des Anderen etablieren zu ko¨nnen. Sie beginnt die Pru¨fung in der Form der Fragestellung. Der in seiner Existenz Sichere wird dem in seinem Sein Verunsicherten gegenu¨bergestellt. Es ist das schlechte Gewissen, das der Macht Existenz verleiht. Die Pru¨fung ist nach Michel Foucault ein zentrales Verfahren der U¨berwachung, Kontrolle, Nivellierung und Vernuetzlichung in der modernen Disziplinargesellschaft, welche die Norm gegen das Gesetz stellt, die Nutzbarmachung der Subjekte gegen Repression, Abstrafung und Vernichtung. Die Pru¨fung¨ kombiniert die Techniken der u¨berwachenden Hierarchie mit denjenigen der nomierenden Sanktion. Sie ist ein normierender Blick, eine qualifizierende, das Zeremoniell der Macht, de Entfaltung der SWke und die Ermittlng der Wahrheit. Kafkas Pruefungsdarstellungen und Verho¨rsituationen, seien sie auch zumeist ho¨chst symbolisch, metaphorisch konzipiert, weisen auf diese Erfahrung und implizieren durchaus jenen aufs Extrajuridische sich richtenden Machtbegriff. Sie entsprechen auch aufs genaueste dem Begriff der Disziplinarmacht. Universale Kontrolle - ihr Zentrum ist das die Marter des vorbu¨rgerlichen Strafrechts ablo¨sende produktiv fungierende Gefa¨ngnis - konstituiert ein Feld der Macht, welches als extrajuridlsches die Welt des Gesetzes auflo¨st. Disziplinierung, Kontrolle, Qualifizierung, O¨konomisierung, Symbolisierung, Normalisierung, Sozialisierung usw. heißen die modernen Prozeduren, die in Familien, Schulen, Kliniken, psychatrischen Anstalten, Fabriken, Kasernen und Gefa¨gnissen entwickelt werden. Die U¨berwachungs- und Disziplinierungsgesellschaft ist zwar hierarchisch struktiert, aber eine definierbare Gewaltinstanz ist in ihr nicht auszumachen. Die Kontrolle wirkt wie ein Beziehungsnetz von oben nach unten und bis zu einem gewissen Grad auch von unten nach oben und nach den Seiten. Dieses Netz ha¨lt das Ganze und durchsetzt es mit Machtwirkungen, die sich gegenseitig stu¨tzen: pausenlos u¨berwachte U¨berwacher. In der hierarchsierten U¨berwachung der Disziplinen ist die Macht keine Sache, die man innehat, kein Eigentum, das man u¨berrtra¨gt, sondem eine Maschinerie, die funktioniert. Zwar gibt ihr der pyramidenfo¨rmige Aufbau einen Chef, aber es ist der gesamte Apparat, der Macht produziert. Kafka, unter allen Dichtern der gro¨ßte Experte der Macht, stellt in seinen Aphorismen und Fragmenten eben solche - u¨ber Juridische, u¨ber direkte Herrschafts- und Knechtschaftsverha¨ltnisse oder Repressionen hinausgehende - Machtprozeduren dar und reflektiert auch theoretisch u¨ber sie.

施肥水準이 강남콩의 生育, 莢收量 및 根瘤形成에 미치는 影響

權五達,李政明 경희대학교 부설 식량자원개발연구소 1984 硏究論文集 Vol.5 No.-

This experiment was conducted to investigate the effect of varying levels of fertilizer on the growth, pod yield, and root nodule development in pot-grown snapbean cultivars. Early flowering rate was low in 'Pinto' and 'White Half Runner' and also reduced by increased level of fertilizers in most cultivars. However, fertilizer levels did not appear to have any particular pattern of pod yield distribution among 3 harvest dates. Total pod yield and pod number per plant were high in 'White Half Runner' and 'Pinto' and in 2g/pot/week (N:P_(2)O_(5):K_(2)O=17:21:17) fertilized plants even though cultivars showed different response to fertilizer levels. Shoot growth was high in 2g-fertilized plants and in 'Stringless Green Pod' cultivar, which showed the lowest pod yield and the lowest green pod productivity (pod to shoot ratio). The formation of root nodules was significantly reduced by fertilizer application and also influenced by cultivars.