Pure 3D laparoscopy versus open right hemihepatectomy in a donor with type II and III portal vein variations

Kyungho Park,Ahmed Shehta,Jeong-Moo Lee,Suk Kyun Hong,Kyung Chul Yoon,Jae-Hyung Cho,Nam-Joon Yi,Kwang-Woong Lee,Kyung-Suk Suh 한국간담췌외과학회 2019 Annals of hepato-biliary-pancreatic surgery Vol.23 No.4

Backgrounds/Aims: Pure laparoscopic living donor right hemihepatectomy (PLDRH) has been performed in many experienced centers. However, portal vein variations still remain challenging thus disturbing the widespread of PLDRH in many centers. PLDRH when integrated with 3-dimensional laparoscopy and indocyanine green (ICG) near-infrared fluorescence cholangiography is safe and feasible. Methods: We reviewed 19 donors with separated right anterior and right posterior portal veins who underwent living donor right hemihepatectomy between January 2014 and December 2016. We compared the clinical outcomes of PLDRH and conventional open right hemihepatectomy (CDRH). Results: 6 donors (31.6%) underwent PLDRH while 13 donors (68.4%) underwent CDRH. There was no intraoperative complications, transfusions and open conversions in the PLDRH donors. The total operative time was longer in PLDRH (356.5 vs. 244.5 minutes, p=0.003). However, the length of hospital stay (8.5 vs. 9.0 days, p=0.703), blood loss (450.0 vs. 393.6 ml, p=0.557) and complication rate (16.6% vs.27.3%; p=0.327) did not differ between the two groups. Conclusions: PLDRH is safe and feasible in donors with type II and III portal vein variations. Further prospective comparative studies are needed to prove the safety and efficacy of PLDRH.

ER stress stimulates production of the key antimicrobial peptide, cathelicidin, by forming a previously unidentified intracellular S1P signaling complex

Park, Kyungho,Ikushiro, Hiroko,Seo, Ho Seong,Shin, Kyong-Oh,Kim, Young il,Kim, Jong Youl,Lee, Yong-Moon,Yano, Takato,Holleran, Walter M.,Elias, Peter,Uchida, Yoshikazu National Academy of Sciences 2016 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.113 No.10

<P>We recently identified a previously unidentified sphingosine-1-phosphate (S1P) signaling mechanism that stimulates production of a key innate immune element, cathelicidin antimicrobial peptide (CAMP), in mammalian cells exposed to external perturbations, such as UVB irradiation and other oxidative stressors that provoke subapoptotic levels of endoplasmic reticulum (ER) stress, independent of the well-known vitamin D receptor-dependent mechanism. ER stress increases cellular ceramide and one of its distal metabolites, S1P, which activates NF-kappa B followed by C/EBP alpha activation, leading to CAMP production, but in a S1P receptor-independent fashion. We now show that S1P activates NF-kappa B through formation of a previously unidentified signaling complex, consisting of S1P, TRAF2, and RIP1 that further associates with three stress-responsive proteins; i.e., heat shock proteins (GRP94 and HSP90 alpha) and IRE1 alpha. S1P specifically interacts with the N-terminal domain of heat shock proteins. Because this ER stress-initiated mechanism is operative in both epithelial cells and macrophages, it appears to be a universal, highly conserved response, broadly protective against diverse external perturbations that lead to increased ER stress. Finally, these studies further illuminate how ER stress and S1P orchestrate critical stress-specific signals that regulate production of one protective response by stimulating production of the key innate immune element, CAMP.</P>

Simple solutions of an opening in elastic-brittle plastic rock mass by total strain and incremental approaches

Park, Kyungho Techno-Press 2017 Geomechanics & engineering Vol.13 No.4

This study deals with simple solutions for a spherical or circular opening excavated in elastic-brittle plastic rock mass compatible with a linear Mohr-Coulomb (M-C) or a nonlinear Hoek-Brown (H-B) yield criterion. Based on total strain approach, the closed-form solutions of stresses and displacement are derived simultaneously for circular and spherical openings using original H-B and M-C yield criteria. Two simple numerical procedures are proposed for the solution of generalized H-B and M-C yield criteria. Based on incremental approach, the similarity solution is derived for circular and spherical openings using generalized H-B and M-C yield criteria. The classical Runge-Kutta method is used to integrate the first-order ordinary differential equations. Using three data sets for M-C and H-B models, the results of the radial displacements, the spreading of the plastic radius with decreasing pressure, and the radial and circumferential stresses in the plastic region are compared. Excellent agreement among the solutions is obtained for all cases of spherical and circular openings. The importance of the use of proper initial values in the similarity solution is discussed.

Pharmacokinetics of Second-Line Antituberculosis Drugs after Multiple Administrations in Healthy Volunteers

Park, Sang-In,Oh, Jaeseong,Jang, Kyungho,Yoon, Jangsoo,Moon, Seol Ju,Park, Jong Sun,Lee, Jae Ho,Song, Junghan,Jang, In-Jin,Yu, Kyung-Sang,Chung, Jae-Yong American Society for Microbiology 2015 Antimicrobial Agents and Chemotherapy Vol.59 No.8

<P>Therapeutic drug monitoring (TDM) of second-line antituberculosis drugs would allow for optimal individualized dosage adjustments and improve drug safety and therapeutic outcomes. To evaluate the pharmacokinetic (PK) characteristics of clinically relevant, multidrug treatment regimens and to improve the feasibility of TDM, we conducted an open-label, multiple-dosing study with 16 healthy subjects who were divided into two groups. Cycloserine (250 mg), <I>p</I>-aminosalicylic acid (PAS) (5.28 g), and prothionamide (250 mg) twice daily and pyrazinamide (1,500 mg) once daily were administered to both groups. Additionally, levofloxacin (750 mg) and streptomycin (1 g) once daily were administered to group 1 and moxifloxacin (400 mg) and kanamycin (1 g) once daily were administered to group 2. Blood samples for PK analysis were collected up to 24 h following the 5 days of drug administration. The PK parameters, including the maximum plasma concentration (<I>C</I><SUB>max</SUB>) and the area under the plasma concentration-time curve during a dosing interval at steady state (AUC<SUB>τ</SUB>), were evaluated. The correlations between the PK parameters and the concentrations at each time point were analyzed. The mean <I>C</I><SUB>max</SUB> and AUC<SUB>τ</SUB>, respectively, for each drug were as follows: cycloserine, 24.9 mg/liter and 242.3 mg · h/liter; PAS, 65.9 mg/liter and 326.5 mg · h/liter; prothionamide, 5.3 mg/liter and 22.1 mg · h/liter; levofloxacin, 6.6 mg/liter and 64.4 mg · h/liter; moxifloxacin, 4.7 mg/liter and 54.2 mg · h/liter; streptomycin, 42.0 mg/liter and 196.7 mg · h/liter; kanamycin, 34.5 mg/liter and 153.5 mg · h/liter. The results indicated that sampling at 1, 2.5, and 6 h postdosing is needed for TDM when all seven drugs are administered concomitantly. This study indicates that PK characteristics must be considered when prescribing optimal treatments for patients. (This study has been registered at ClinicalTrials.gov under registration no. NCT02128308.)</P>

Transformative Learning : Sojourners' Experiences in Intercultural Adjustment

Park, Kyungho 한국성인교육학회 2003 Andragogy Today : International Journal of Adult & Vol.6 No.1

이 연구에서는 다문화적응을 토대로 외국 유학생들의 의미구조의 변화를 조사하였다. 동아시아에서 온 대학원학생들을 대상으로 의도적인 샘플링을 25명 선정하여 질적 연구를 시행하였다. 이 연구를 통해서 외국대학원생들에게서 다문화적응을 통해 전환학습이 발생하였고, 의미구조의 본질은 메지로우(Mezirow)의 전환이론에 좀 더 다양한 시각을 제공하였음을 발견할 수 있었다. 미국의 개인주의와 학문구조를 포함하는 사회 문화적인 상황배경이 학생들에게 좀더 자기중심적인 삶을 살도록 촉진하였고, 그들이 좀더 자신의 삶에 집중함으로써 자신들의 정체성을 발견하였다. 학문구조를 통하여 학생들은 자기가치(self-esteem)가 증진되었고 이는 그들의 관점의 변화를 촉진시켰다. 또한 이 연구에서 관점전환(perspective transformation)을 야기하는 주관적 요인들의 중요성을 발견하였다. 모델링과 친구관계를 포함하는 사회적 관계가 중요한 변화의 요인이었다. 긍정적인 감정들을 통하여 주로 동화학습을 통해 그들의 의미체계(meaning schemes)들을 변화시켰다. 축적된 의미체계의 변화들은 학생들에게 관점전환을 야기하는데 중요한 역할을 하였다. 부정적인 감정들은 학생들에게 비판적인 자아성찰에 빠지게 하여 관점전환을 촉진시켰다. 비판적 성찰과 감정이 상호 작용하여 학생들에게 가정에 대한 비판적 성찰에 참여하게 하여 관점전환이 발생하도록 하였다. 동화 및 전환학습은 학생들에게 새로운 자아상(self-image)을 형성하도록 하였는데 이는 열린 관점, 자신감의 증진, 가치 변화, 그리고 새로운 방식 하에서의 생각과 삶이다. 이 연구는 다문화적응을 통하여 전환학습이론의 본질에 좀더 통합적인 시각을 제공하는데 기여했다. 주관적 요인들과 사회 문화적 상황의 역할의 중요성을 인정함에 따라 전환학습이론은 점차 확대되고 확증되고 있다. This research examined the nature of changes in meaning structures among sojourners through the framework of intercultural adjustment. A qualitative research design was employed. Twenty-five international graduate students from East Asia were selected through a purposeful sampling procedure. Semi-structured interviews were conducted and the constant comparative approach was employed for data analysis. The major findings indicated that the sojourners experienced transformative learning through intercultural adjustment. The nature of changes in meaning structures provided more diverse perspective in the transformative learning theory. This study also found the significant role of subjective factors that brought perspective transformation. The role of social relationship including modeling and friendship was a significant factor. Both assimilative and transformative learning resulted in the building of a new self-image among the sojourners characterized by openness, self-confidence, changed values, and new ways of thinking and life. Through the framework of intercultural adjustment, this study revealed more integrated perspectives on the nature of transformative learning theory. The transformative learning theory was enlarged and validated by acknowledging the significant role of social and cultural context and subjective factors.

Self-Assembly-InducedFormation of High-Density SiliconOxide Memristor Nanostructures on Graphene and Metal Electrodes

Park, Woon Ik,Yoon, Jong Moon,Park, Moonkyu,Lee, Jinsup,Kim, Sung Kyu,Jeong, Jae Won,Kim, Kyungho,Jeong, Hu Young,Jeon, Seokwoo,No, Kwang Soo,Lee, Jeong Yong,Jung, Yeon Sik American ChemicalSociety 2012 Nano letters Vol.12 No.3

<P>We report the direct formation of ordered memristor nanostructureson metal and graphene electrodes by a block copolymer self-assemblyprocess. Optimized surface functionalization provides stacking structuresof Si-containing block copolymer thin films to generate uniform memristordevice structures. Both the silicon oxide film and nanodot memristors,which were formed by the plasma oxidation of the self-assembled blockcopolymer thin films, presented unipolar switching behaviors withappropriate set and reset voltages for resistive memory applications.This approach offers a very convenient pathway to fabricate ultrahigh-densityresistive memory devices without relying on high-cost lithographyand pattern-transfer processes.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2012/nalefd.2012.12.issue-3/nl203597d/production/images/medium/nl-2011-03597d_0003.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl203597d'>ACS Electronic Supporting Info</A></P>

Metal-Free Decarboxylative Three-Component Coupling Reaction for the Synthesis of Propargylamines

Park, Kyungho,Heo, Yumi,Lee, Sunwoo American Chemical Society 2013 ORGANIC LETTERS Vol.15 No.13

<P>A metal-free decarboxylative three-component coupling reaction was developed. When alkynyl carboxylic acids, paraformaldehyde, and amines were reacted in CH<SUB>3</SUB>CN at 65 °C for 3 h, the desired propargylamines were obtained in good yields. This coupling reaction also showed good yield in water solvent. This reaction showed higher selectivity toward alkynyl carboxylic acids than a terminal alkyne.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/orlef7/2013/orlef7.2013.15.issue-13/ol401358t/production/images/medium/ol-2013-01358t_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ol401358t'>ACS Electronic Supporting Info</A></P>

Phytochemical Modulation of Sphigosine-1-Phosphate Signal Enhances Epidermal Innate Immunity through Cathelicidin Antimicrobial Peptide Production

Kyungho Park,Kyong-Oh Shin,Young Il Kim,Yong-Moon Lee,Walter M. Holleran,Peter M. Elias,Yoshikazu Uchida 한국식품영양과학회 2014 한국식품영양과학회 학술대회발표집 Vol.2014 No.10

Development of AI Based Micro-Blast Scabbling Decommissioning Technology for Concrete Structures in Nuclear Power Plant

Kyungho Lee,Sewon Chung,Kihyun Park,Seonghee Park 한국방사성폐기물학회 2021 한국방사성폐기물학회 학술논문요약집 Vol.2021 No.11

Palladium‐Catalyzed Sonogashira Reaction for the Synthesis of Arylalkynecarboxylic Acids from Aryl Bromides at Low Temperature

Park, Kyungho,You, Jung‐,Min,Jeon, Seungwon,Lee, Sunwoo WILEY‐VCH Verlag 2013 European journal of organic chemistry Vol.2013 No.10

<P><B>Abstract</B></P><P>A variety of aryl bromides were coupled with propiolic acid in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) and catalyst Pd(PPh<SUB>3</SUB>)<SUB>4</SUB> to afford the corresponding arylalkynecarboxylic acids in good yields at low temperature. This method showed good tolerance toward functional groups such as alkoxy, ketone, ester, aldehyde, cyano, nitro, and hydroxy. Under these conditions, propiolic acid showed higher reactivity than any other compound containing terminal alkyne groups. According to the mechanistic studies, the key reaction step for the high reactivity of propiolic acid might be ligand exchange between the acetylide and bromide at palladium, and/or reductive elimination, but not the oxidative addition step.</P>