Elderly kidney transplant recipients have favorable outcomes but increased infection-related mortality

임정훈,Lee Ga Young,Jeon Yena,Jung Hee-Yeon,Choi Ji Young,CHO, JANG-HEE,Park Sun Hee,김용림,Kim Hyung-Kee,Huh Seung,유은상,Won Dong Il,Kim Chan-Duck 대한신장학회 2022 Kidney Research and Clinical Practice Vol.41 No.3

Background: The number of elderly patients with end-stage kidney disease has been increasing, but the outcomes of kidney transplants (KT) remain poorly understood in elderly patients. Therefore, we evaluated the clinical outcomes of elderly KT recipients and analyzed the impact of elderly donors. Methods: This retrospective cohort study included patients who underwent KT between 2000 and 2019. KT recipients were divided into four groups according to a combination of recipient and donor age (≥60 or <60 years); elderly recipients: old-to-old (n = 46) and young-to-old (n = 83); young recipients: old-to-young (n = 98) and young-to-young (n = 796). We compared the risks of mortality, graft failure, and acute rejection between groups using Cox regression analysis. Results: The incidence of delayed graft function, graft failure, and acute rejection was not different among groups. Annual mean tacrolimus trough level was not lower in elderly recipients than young recipients during 10-year follow-up. Mortality was significantly higher in elderly recipients (p = 0.001), particularly infection-related mortality (p < 0.001). In multivariable Cox regression analysis, old-toold and young-to-old groups had increased risk of mortality (adjusted hazard ratio [aHR], 2.89; 95% confidence interval [CI], 1.14– 7.32; p = 0.03; aHR, 3.06; 95% CI, 1.51–6.20; p = 0.002). However, graft failure and acute rejection risks were not increased in elderly recipients. Conclusion: In elderly recipients, graft survival and acute rejection-free survival were not inferior to those of young recipients. However, mortality, especially risk of infection-related death, was increased in elderly recipients. Thus, low immunosuppression intensity might help decrease mortality in elderly recipients.

시험성토 단면에서의 다짐에너지에 따른 LFWD 변형계수의 변화

최찬용(Choi Chan-Young),김현기(Kim Hyun-Ki),배재훈(Bae Jae-Hoon) 한국철도학회 2008 한국철도학회 학술발표대회논문집 Vol.- No.-

PLT where from site is used mainly with compaction maintenance of quality, CPLT and LFWD, in order to be a Young"s modulus of using a direct arrival wave executed a site experiment. According to the roller compaction number of times measured the degree which changes and a promise management aptitude evaluation executed.

Peroxide 개질에 따른 Nylon 12 elastomer의 특성 연구

최명찬 ( Myung Chan Choi ),정지연 ( Ji Yeon Jung ),장영욱 ( Young Wook Chang ) 한국고무학회 2013 엘라스토머 및 콤포지트 Vol.48 No.1

용융상태에서 nylon 12 elastomer에 소량의 dicumyl peroxide (DCP) 와 triallyl cyanuate (TAC)를 첨가하여 nylon 12 elastomer를 부분적으로 가교시켰으며, 이에 따른 nylon 12 elastomer의 기계적, 동적기계적 그리고 유변학적 특성을 tensile test, DMA, small amplitude oscillating rheometer를 이용하여 각각 알아보았다. TAC의 함량이 증가함에 따라 인장탄성률과 영률은 증가하고, 파단신율은 감소하였다. DMA 측정결과, DCP로 부분적으로 가교시킨 nylon 12 elastomer의 PTMG상의 유리전이온도는 순수한 nylon 12 elstomer에 비해 증가하였고, storage modulus는 nylon 12상의 용융온도 이상에서도 거의 일정한 값을 나타내었다. 부분적으로 가교시킴에 따른 유변학적 특성의 변화는 TAC의 함량이 증가함에 따라 solid like behavior와 shear thinning behavior가 점점 뚜렷하게 나타남을 알 수 있었다. 이로부터 nylon 12 elastomer를 용융상태에서 부분적으로 가교시킴으로써 용융가공성을 저하시키지 않으면서, 기계적 물성은 효과적으로 향상시킬 수 있었으며, 특히, nylon 12 elastomer의 사용가능 온도범위를 증가시킬 수 있었다. Nylon 12 elastomer was slightly crosslinked in molten state by the addition of small amount of dicumyl peroxide (DCP) as a crosslink agent and triallycyanuate (TAC) as a co-agent during melt compounding at 160 oC in an internal mixer. The effect of the peroxide crosslinking on mechanical, dynamic mechanical and rheological properties of the nylon 12 elastomer was investigated by means of tensile testing, dynamic mechanical analysis (DMA) and small amplitude oscillating rheometer, respectively. With modification, there is an improvement in tensile modulus and Young`s modulus with decease in elongation at break. DMA results for peroxide modified nylon 12 elastomers demonstrated that the glass transiaiton temperature of PTMG segment shifted to higher temperature and the storage modulus remained constant above the melting temperature of nylon 12 segments. Melt rheological studies revealed that the peroxide modified nylon 12 elastomer exhibited a more solid like behavior and stronger shear thinning behavior compared to neat nylon 12 elastomer, which was more prominent at higher TAC content in the polymer matrix. The peroxide modified nylon 12 elastomer exhibited good elastic recoverability and improved mechanical properties without sacrificing melt processibilty, and especially the service temperature range increased as compared to neat nylon 12 elastomer.

가우시안 빔 프로파일의 CPT를 위한 비선형 주사속도변조

최덕규,한찬호,정영헌 경운대학교 산업기술연구소 2001 産業技術硏究論文誌 Vol.3 No.2(B)

A scan velocity modulation(SVM) technique has been widely used for compensating the deterioration of picture quality due to the beam profile effect of the color picture tube(CPT). In conventional SVM system the so-called linear SVM method has been employed, whose modulation velocity is linearly proportional to the variation in the video signal amplitude. However, the effect of picture quality improvement is irregular with video signal amplitude in the linear SVM. In this paper we report a theoretical analysis of the SVM effect on the spatial brightness distribution of CPT according to the variations in luminance signal amplitude and differentiation circuit characteristic. We also propose a nonlinear SVM method based on the results of the theoretical analysis for optimum picture quality improvements. In computer simulation we confirmed uniform improvements in picture quality by the SVM of nonlinear amplitude transfer characteristic.

Paraquat 유도독성에 대한 Ginkgo biloba Extract의 독성경감효과 (Ⅰ)

최병기,김영찬 한국환경독성학회 1998 환경독성보건학회지 Vol.13 No.2

Reactive oxygen species (ROS) are highly reactive molecules due to their unpaired electron. They have been suspected as one of the major tissue damage inducers in biological metabolic systems. Antioxidant enzymes, such as catalase and superoxide dismutase, could not repair all the oxidative damages resulting from those excessive toxic ROS. It is, therefore, urgent to develop effective antioxidants to relieve from the oxidative damages. In this study antioxidative effects were investigated by using two flavonoids such as quercetin and naringenin and a flavonoid-rich extract, Ginkgo biloba extract in combination with paraquat that is known as a strong generator of oxygen radicals. The results are summeringed as follows: 1. To assess radical scavenging ability reduction concentrations (IC_(50)) of 1,1-diphenyl-2-picry1hydrazine (DPPH) within 15 minutes were measured. The values of the IC50 of quercetin and Ginkgo biloba extract were 15.4μM and 13.2μg/ml, respectively. Their radical removing activities showed concentration-dependent manners. 2. In the hydrogen peroxide assay by using PMS-NADH system, quercetin, naringenin and Ginkgo biloba extract led to removing hydrogen peroxide in concentration-dependent manner whose removing abilities at 100μM or 100μg/ml were 75.6, 25.8 and 26.0%, respectively. 3. In the hydrogen peroxide-induced rat blood hemolysis assay all three compounds led to similar effects whose hemolysis inhibition ratios at 100μM or 100μg/ml were 68.0, 5.14 and 55.8%, respectively. 4. In the xanthinee oxidase assay by measuring degree of NADH oxidation in the presence of hypoxanthine and xanthinee oxidase, both quercetin and Ginkgo biloba extract showed excellent activities showing 42.8 and 24.2% inhibiting xanthine oxidase activity at 100μM or 100μg/ml concentrations, respectively. 5. In the mouse liver microsomal NADPH-dependent cytochrome p450 reductase assay, paraquat consumed NADPH in a dose-dependent manner from 0 to I mM paraquat concentrations. When quercetin, naringenin or Ginkgo biloba extract added to this system, they blocked NADPH consumption rates at a concentration-dependent manner whose inhibition ratios of cytochrome p450 reductase at 100μM or 100μg/ml were 63.1, 52.2 and 52.2N6, repectively when compared with those of the 1 mM paraquat treatment. 6. Lactate dehydrogenase (LDH) is frequently used as a membrane toxicity indicator. When paraquat added to the macrophage RAW 264.7 cell live, LDH concentration was increased from 162.4 to 290.3 unit/L. When various concentration of quercetin, naringenin or Ginkgo biloba extract were added to the culture system in the presence of 1 mM paraquat, they decreased LDH concentration-dependent manner, showing 182, 5, 182.1 and 212.3 unit/l of LDH at 100μM or 100μg/ml teratment, repectively. However, in this case, only quercetin and Ginkgo biobla extract increased macrophage viability from 35.5 to 38.0 and 39.7 at the concentration of 100μM or 75 μg/ml when measured MTT assay, within 24hr, respectively. From these results flavonoids of quercetin, naringenin and Ginkgo biloba extract exerted their antioxidant effects by removing oxygen radicals, by blocking oxygen generating enzymes. As a general, naringenin, quercetin and Ginkgo biloba extract showed the useful compounds for scavenger and antioxidant on paraquat induced toxicity.

원자력 발전소 핵연료 재장전을 위한 정지시 방사선준위 저감방법에 관한 연구

최형일,조영찬,오연옥 조선대학교 환경연구소 1999 環境硏究 Vol.15 No.1

During the shutdown of a pressurized water reactor, significant amounts of activated corrosion products were released. The recent recommendations by the Electric Power Research Institute for shutdown procedures aims to remove as much radioactivity as possible from the primary system. The Young-Gwang Nuclear Plant unit 4 performed a study to establish which conditions are reasonable to reduce the level of radioactivity in the primary system. The measurements include analysis of the reactor coolant, radioactivity in addition to boron concentration, pH, dissolved hydrogen and lithium concentration during shutdown. From these data estimates of the relation between Co-58 activity and other chemistry parameters (such as boron concentration, pH, dissolved hydrogen, lihthium concentration) have been made. The early removal of dissoled hydorgen and elevated boron concentration at acid reducing condition could affect the Co-58 dissociation rate. At acid oxidizing condition hydrogen peroxide could affect the dissolution of Co-58 which removed from the primary system. By using the purification ion exchanger remaining Co-58 could be removed to the level which primary manways of steam generator's can be open. The activity levels of each steam generator were lowered by 35% compared with that of last year. It indicates that low pH of the system chemistry through early removal of dissolved hydrogen and elevated boron concentration at high temperature accelerated the dissolution of Co-58.

제주도 서부 연안역의 생물생태학적 기초연구(I) : 고산주변 연안역의 해수특성

최영찬,이준백,고유봉 제주대학교 해양연구소 1994 해양자원연구소연구보고 Vol.18 No.-

만삭 신생아의 기흉

최우경,홍찬의,이동진,허남진,이영환 영남대학교 의과대학 2005 Yeungnam University Journal of Medicine Vol.22 No.2

Background: This study was performed to evaluate the incidence and clinical characteristics of symptomatic pneumothorax in the full-term neonate. Materials and Methods: We retrospectively reviewed the medical records of 32 symptomatic pneumothorax patients in the full term neonates who admitted to the neonatal intensive care unit in Ulsan Dong Kang General Hospital from January, 2000 to December, 2004. The subjects were divided into two groups according to underlying causes; spontaneous pneumothorax group and secondary pneumothrax group, then each clinical characteristics were assessed. Result: Spontaneous pneumothorax patients were 10(31%) and secondary pneumothorax patients were 22(69%). Overall incidence of spontaneous pneumothorax was 0.4%. Most common cause of secondary pneumothorax was pneumonia. Twelve causes(54.5%) among secondary pneumothorax patients were associated with mechanical ventilator care. Clinical characteristics, courses and managements were similar between two groups, but more shorter duration of admission and chest-tube insertion in spontaneous pneumothorax group Conclusion: The patient with symptomatic pneumothorax needs careful observation and proper management with or without underlying respiratory diseases

公害規制가 貿易패턴에 미치는 影響

崔文燦,徐英哲 東亞大學校 經營問題硏究所 1994 經營論叢 Vol.15 No.-

제주시내 주요 하천의 이화학적 수질조사 연구

최영찬,박길순 제주대학교 1986 논문집 Vol.23 No.-

Six different sites in major streams of Cjeju City were selected for the surveying of chemical water quality from July 1984 to June 1985. The results are as follows. 1. pH range and average were 7.2-8.7 and 7.7 respectively. No significant differecnces in seasons and sites were obseved 2. DO were 0.33-9.10 ppm and 3.53 ppm respectively which belong to 3rd class in the environmental criteria for daily life and was bellow the concentrates of mesosaprobic waters marine organism (5.0ppm). 3. BOD were 17.5-232.4ppm, 64.9 ppm respectively which was more than two times higher than 30ppm-the water quality criteria for sewage treatment terminal. 4. COD were 12.6-102.1pprn, 30.2ppm respectively which was three times higher than l0ppm-the environmental conservation criteria for daily life. 5 NH^(+)_(4)-N which is early decomposing product of organic pollution material were 3.01 -29.98ppm, 4.11ppm respectively and showed higher figure than other regions stream water.