Study on Microstructure and Mechanical Properties of the Al–25Cr–5Si (at%) Alloy Powder Using Gas-Atomization and SPS Process

Yong‑Ho Kim,Hyo‑Sang Yoo,Jeong‑Han Lee,Ik‑Hyun Oh,Hyun‑Kuk Park,Hyeon‑Taek Son 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

In order to investigate the microstructure and mechanical properties on Al–25Cr–5Si (at%) alloy, a mixed powder with pureelements and an alloy powder using a gas atomization process were used. Fine and high purity Al–25Cr–5Si (at%) alloypowder was successfully prepared by gas atomization and densified using a spark plasma sintering (SPS) process. The overallpowder size distribution of the mixed Al, Cr, and Si elemental powders was in the range of 10–15 μm. The atomized Al–Cr–Sialloy powder was fine and spherical in morphology and difficult to be formed by intermetallic formation. Densification wasclearly confirmed at 1000 °C, with almost isolated pores formed, by clear removal of pores between particles, deformationof particles, an increase in the number of contacts, and a change in size between particles. As a result of XRD analysis ofthe sintered compacts, single phase was observed using the mixed powder, but the compact using gas atomization remainedthe alloy phase even at the process temperature. The Vickers hardness of the compacts by mixed powder was observed at59.70 Hv and the compact using gas atomized powders on the temperature 1000 °C of the Vickers hardness increased to702.6 Hv. The compressive yield strength of the compact with mixed powder was 195.24 MPa and the compressive strengthof the compact with gas atomized powder increased to 802.07 MPa. It is considered not to be decomposed by the AlCrSi,Al13Cr4Si4and Al8Cr5phases sintering process, resulting from the improvement of mechanical properties.

Analysis of Outer Membrane Proteins of Yersinia enterocolitica Isolated from Mountainspring Water and Pig

( Sung Jae Shin ),( Joo Youn Park ),( In Soo Choi ),( Na Ri Shin ),( Deog Yong Lee ),( Young Wook Cho ),( Yong Ha Park ),( Han Sang Yoo ) 한국미생물 · 생명공학회 2002 Journal of microbiology and biotechnology Vol.12 No.4

Yersinia enterocolitica causes various diseases in humans, including enteritis. The onset of such diseases is closely related with the expression of important virulence factors, particularly outer membrane proteins (OMPs). The expression of OMPs depends on several factors, including temperature, and origin, biotype and serotype of the bacteria. Recently, concerns over food safety have increased along with the demand for the development of sensitive, rapid, and pathogen-specific detection methods. To develop a suitable detection method for Y. enterocolitica isolated from Korean moutainspring water and pig feces, the OMP expression patterns were analyzed phenotypically and immunologically using 12 representative strains from 51 Y. enterocolitica Korean isolates. A 38-kDa OMP was commonly observed in all strains. However, additional OMPs were also observed in different biotypes and serotypes as well as bacterial origins, by incubating Y. enterocolitica at a low temperature. The specificity of the 38-kDa OMP was confirmed by a Western blot analysis with antisera against Y. enterocolitica and Brucella abortus. The results, therefore, indicate that the 38-kDa OMP could be used as a marker for detecting Y. enterocolitica in the environment or for seromonitoring.

A novel agonistic antibody to human death receptor 4 induces apoptotic cell death in various tumor cells without cytotoxicity in hepatocytes.

Sung, Eun-Sil,Park, Kyung-Jin,Lee, Seung-Hyun,Jang, Yoon-Seon,Park, Sang-Koo,Park, Yoo-Hoi,Kwag, Won-Jae,Kwon, Myung-Hee,Kim, Yong-Sung American Association for Cancer Research, Inc 2009 Molecular Cancer Therapeutics Vol.8 No.8

<P>The proapoptotic tumor necrosis factor-related apoptosis inducing ligand (TRAIL) receptors death receptor (DR) 4 and DR5 are attractive targets to develop the receptor-specific agonistic monoclonal antibodies (mAb) as anticancer agents because of their tumor-selective cell death-inducing activity. Here, we report a novel agonistic mAb, AY4, raised against human DR4 in mice. ELISA analysis revealed that AY4 specifically bound to DR4 without competition with TRAIL for the binding. Despite distinct binding regions of AY4 on DR4 from those of TRAIL, AY4 as a single agent induced caspase-dependent apoptotic cell death of several tumor types through the extrinsic and/or intrinsic pathways without substantial cytotoxicity to normal human hepatocytes. Further, the AY4-sensitive cells followed the same cell death characteristics classified as type I and type II cells by the response to TRAIL, suggesting that the cell death profiles in responses to DR4 and/or DR5 stimulation are determined by the downstream signaling of the receptor rather than the kind of receptor. Noticeably, AY4 efficiently induced cell death of Jurkat cells, which have been reported to be resistant to other anti-DR4 agonistic mAbs, most likely due to the unique epitope property of AY4. In vivo administration of AY4 significantly inhibited tumor growth of human non-small cell lung carcinoma preestablished in athymic nude mice. Conclusively, our results provide further insight into the DR4-mediated cell death signaling and potential use of AY4 mAb as an anticancer therapeutic agent, particularly for DR4-responsive tumor types.</P>

Telomere maintenance in endometrial cancers: Telomerase or alternative lengthening of telomeres?

( Yoo Kyung Lee ),( Hyun Hoon Chung ),( Jae Weon Kim ),( Yong Sang Song ),( Soon Beom Kang ),( Noh Hyun Park ) 대한산부인과학회 2012 대한산부인과학회 학술대회 Vol.98 No.-

To study the telomere maintenance mechanism in endometrial carcinoma, endometrial hyperplasia, and normal endometrium, and to evaluate their relation with carcinogenesis and progression of endometrial carcinoma. Telomerase activity, hTERT expression, and alternative lengthening of telomeres (ALT) status were determined in 131 endometrial samples (85 cases of endometrial cancer, 16 cases of endometrial hyperplasia, and 30 cases of normal endometrium) by telomeric repeat amplification protocol (TRAP), immunohistochemical method, and APB assay. In TRAP assay, 52 endometrial cancer samples (61.2%), 9 cases of endometrial hyperplasia (56.3%), and 10 cases (33.3%) of normal endometrium demonstrated increased levels of telomerase activity. Immunohistochemical staining for hTERT was present in 43 (50.6%) of endometrial cancer and none of endometrial hyperplasia samples and normal endometrial tissues. ALT status according to APB assay showed positive results in 15 (17.6%) patients. Whereas increased telomerase activity was not associated with stage or prognosis but with grade and histology, ALT status was correlated with prognosis as well as grade and histology. Telomere maintenance mechanisms are closely correlated with the grade and histologic type of endometrial cancer. ALT may play an important role in the regulation of endometrial cancer progression and high grade histology.

Congenital nasolacrimal duct obstruction: irrigation or probing?

Yong Sun Kim,Sung Chur Moon,Kyoung Won Yoo 대한안과학회 2000 Korean Journal of Ophthalmology Vol.14 No.2

The authors investigated the efficacy of antibiotic irrigation as the therapeutic option in congenital nasolacrimal duct obstruction. We retrospectively reviewed the medical record of 76 patients’ eyes in whom congenital nasolacrimal duct obstruction had been diagnosed. In 50 of these patients, the colonizing microorganism was identified and, irrigation through canaliculi was performed using antibiotics of suitable sensitivity. Nasolacrimal system probing was performed on 26 patients as the control group. Treatment was regarded successful when over a 4 week period epiphora or mucous discharge disappeared and when saline passed without resistance on irrigation. 96.0% of patients in the irrigation group and 84.6% of patients in probing group were treated successfully. There was no statistical difference in the success rate between the two groups (P=0.173). The recovery period based on culture results was 3.22±0.37 months in the group in which microorganisms were isolated and 2.39±0.35 months in the group in which no organisms were isolated. There were no statistically significant differences in the success rates between the group in which there was growth and the group in which there was no growth (P=0.1308). Thus a similar result was obtained using nasolacrimal probing and canaliculus antibiotic irrigation in congenital nasolacrimal duct obstruction. Antibiotic irrigation is a safe and simple therapeutic option in congenital nasolacrimal duct obstruction.

ORiginal Article : A Multicenter Phase II Trial of Gemcitabine Plus Oxaliplatin in Unresectable Gallbladder Cancer

( Sang Myung Woo ),( Sang Hyub Lee ),( Ji Won Yoo ),( Ki Young Yang ),( Jung Gyun Seo ),( Joo Kyung Park ),( Jin Hyeok Hwang ),( Woo Jin Lee ),( Ji Kon Ryu ),( Yong Tae Kim ),( Yong Bum Yoon ) The Editorial Office of Gut and Liver 2013 Gut and Liver Vol.7 No.5

Background/Aims: No standard chemotherapy has been established for advanced gallbladder cancer. The authors studied the activity and tolerability of a gemcitabine and ox-aliplatin (GEMOX) combination in unresectable gallbladder cancer (GBC). Methods: Adult patients with pathologically confirmed unresectable GBC were prospectively recruited at three centers. No patient had received prior chemotherapy or radiotherapy. Patients received cycles of gemcitabine at 1,000 mg/m2 on day 1, followed by oxaliplatin at 100 mg/m2 on day 2, every 2 weeks. The primary study endpoint was time to progression. Results: Forty patients with unresect-able GBC were enrolled. The median age was 60 years (range, 38 to 79 years). All patients showed good performance status. Of the 33 analyzable patients, 12 achieved partial re-sponse (36%), 17 stable disease (52%), and four progressive disease (12%). No patient achieved a complete response. The tumor control rate was 88%. At a median follow-up of 6.8 months, the median time to progression was 5.3 months (95% confidence interval [CI], 3.7 to 6.9), and median overall survival was 6.8 months (95% CI, 6.1 to 7.5). Nine of the 40 patients (23%) experienced at least a grade-3 adverse event, but no patient experienced a grade-4 adverse event. Conclu-sions: GEMOX combination therapy is a feasible option and is well tolerated in unresectable GBC. (Gut Liver 2013;7:594-598)

Identification of NBS1 as a novel prognostic biomarker in BRCAness ovarian cancer

( Yoo Kyung Lee ),( Hyun Sook Lee ),( Hyun Hoon Chung ),( Jae Weon Kim ),( Yong Sang Song ),( Soon Beom Kang ),( Noh Hyun Park ) 대한산부인과학회 2011 대한산부인과학회 학술대회 Vol.97 No.-

Estimating Suitable Probability Distribution Function for Multimodal Traffic Distribution Function

Sang-Lok Yoo,Jae-Yong Jeong,Jeong-Bin Yim 해양환경안전학회 2015 海洋環境安全學會誌 Vol.21 No.3

The purpose of this study is to find suitable probability distribution function of complex distribution data like multimodal. Normal distribution is broadly used to assume probability distribution function. However, complex distribution data like multimodal are very hard to be estimated by using normal distribution function only, and there might be errors when other distribution functions including normal distribution function are used. In this study, we experimented to find fit probability distribution function in multimodal area, by using AIS(Automatic Identification System) observation data gathered in Mokpo port for a year of 2013. By using chi-squared statistic, gaussian mixture model(GMM) is the fittest model rather than other distribution functions, such as extreme value, generalized extreme value, logistic, and normal distribution. GMM was found to the fit model regard to multimodal data of maritime traffic flow distribution. Probability density function for collision probability and traffic flow distribution will be calculated much precisely in the future.

A Study on the Observation Days of Maritime Traffic Investigation

Sang-Lok Yoo,Seong-Book Park,Young-Soo Park,Jae-Yong Jeong 해양환경.안전학회 2015 海洋環境安全學會誌 Vol.21 No.4

본 연구는 관측일수에 따른 교통량의 신뢰성을 검증하고자 한다. 목포항의 1년간 선박자동식별장치(AIS) 자료를 사용하여 월별, 요일별, 시간별 변화지수를 비교한 후, 각 관측일수에 따른 최대표준오차를 산출하였다. 월별변화지수를 비교한 결과 9월달 1.11, 2월달 0.84로 나타나 9월달이 2월달 교통량 보다 약 32.1 % 많은 것으로 나타났다. 요일변화지수는 화요일 1.05, 일요일 0.92로 나타나 화요일이 일요일 교통량보다 약 14.1 % 많았다. 해상교통조사는 요일변화지수를 고려하여 최소 1주일 이상 실시하면 최대표준오차를 21 % 이내로 산출할 수 있다. 따라서 해상교통조사 관측시기에 따라 각 변화지수를 적용하여 교통량의 흐름을 반영한 연구가 뒷받침 되어야 하겠다. This study is to compare variation indexes by monthly, weekly and hourly using AIS data, which was collected for 365 days from January 1st to December 31st, 2013 at Mokpo Port and then, computed the maximum standard error by observation days. The comparison of monthly variation indexes showed that the monthly variation indexes for September and February were 1.11 and 0.84, respectively, in turn revealing that the maritime traffic in September was about 32.1 % larger than February. Also, the daily variation indexes for Tuesday and Sunday were 1.05 and 0.92, respectively, in turn revealing that the maritime traffic in Tuesday was about 14.1 % larger than Sunday. When the maritime traffic investigation is executed for at least 1 week in consideration of the daily variation index, it is possible to reduce the maximum standard error rate to be within 21 %. Therefore, if the maritime traffic investigation is made in the month and week with low maritime traffic, each variation index should be applied to reflect the actual maritime traffic.

Probing Electronic Structures of Melts and Glasses under Compression

Sung Keun Lee(이성근),Sun Young Park(박선영),Yoo Soo Yi(이유수),Eun Jeong Kim(김은정),Yong-Hyun Kim(김용현),Hyo-Im Khim(김효임),A Chim Lee(이아침),Saebom Ryu(류새봄),Hoon Khim(김훈),Kwan Young Mun(문관영),Juho Lhee(이주호) 한국암석학회 2020 한국암석학회 학술발표회 논문집 Vol.2020 No.8