Effect of different water temperatures on the growth and blood parameters of red spotted grouper, Epinephelus akaara

Min Joo Kang,Choong Hwan Noh,Sang Woo Hur,Chi Hoon Lee,Young Don Lee,Hea Ja Baek1 한국수산과학회 양식분과 2015 한국수산과학회 양식분과 학술대회 Vol.2015 No.10

Effect of spark plasma sintering conditions on the thermoelectric properties of (Bi_0.25Sb_0.75)₂Te₃ alloys

Lim, Sang-Soon,Kim, Ju-Heon,Kwon, Beomjin,Kim, Seong Keun,Park, Hyung-Ho,Lee, Ki-Suk,Baik, Jeong Min,Choi, Won Jun,Kim, Dong-Ik,Hyun, Dow-Bin,Kim, Jin-Sang,Baek, Seung-Hyub Elsevier 2016 JOURNAL OF ALLOYS AND COMPOUNDS Vol.678 No.-

<P><B>Abstract</B></P> <P>As a field-assisted technique, spark plasma sintering (SPS) enables densification of specimens in a very short period of time compared to other sintering techniques. For high performance thermoelectric material synthesis, SPS is widely used to fabricate nanograin-structured thermoelectric materials by rapidly densifying the nanopowders suppressing grain growth. However, the microstructural evolution behavior of thermoelectric materials by SPS, another important process during sintering, has been rarely studied. Here, we explore SPS as a tool to control the microstructure by long-time SPS. Using p-type (Bi<SUB>0.25</SUB>Sb<SUB>0.75</SUB>)<SUB>2</SUB>Te<SUB>3</SUB> thermoelectric materials as a model system, we systematically vary SPS temperature and time to understand the correlations between SPS conditions, microstructural evolution, and the thermoelectric properties. Our results show that the relatively low eutectic temperature (∼420 °C) and the existence of volatile tellurium (Te) are critical factors to determine both microstructure and thermoelectric property. In the liquid-phase sintering regime, rapid evaporation of Te leads to a strong dependence of thermoelectric property on SPS time. On the other hand, in the solid-phase sintering regime, there is a weak dependence on SPS time. The optimum thermoelectric figure-of-merit (Z) of 2.93 × 10<SUP>−3</SUP>/K is achieved by SPS at 500 °C for 30 min. Our results will provide an insight on the optimization of SPS conditions for materials containing volatile elements with low eutectic temperature.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Spark plasma sintering (SPS) is used to synthesize the thermoelectric (Bi<SUB>0.25</SUB>Sb<SUB>0.75</SUB>)<SUB>2</SUB>Te<SUB>3</SUB>. </LI> <LI> Liquid phase and volatile element are a key for the microstructure and thermoelectric property. </LI> <LI> Thermoelectric figure-of-merit of 2.9 × 10<SUP>−3</SUP>/K is achieved at 500 °C for 30 min. </LI> </UL> </P>

원인 불명의 실신 환자의 진단에 있어서 Head - up tilt Test 의 유용성과 혈관미주신경성 실신 환자의 임상적 특징

윤호중(Ho Joong Youn),정욱성(Wook Sung Chung),백상홍(Sang Hong Baek),김철민(Chul Min Kim),박인수(In Soo Park),김재형(Jae Hyung Kim),최규보(Kyu Bo Choi),홍순조(Soon Jo Hong) 대한내과학회 1994 대한내과학회지 Vol.47 No.2

N/A Background: Syncope, defined as a transient loss of consciousness, is a frequently encountered symptom, but despite thorough clinical and invasive diagnostic investigation, the cause of syncope remains unexplained. In recent years, head-up tilt test has been of increasing interest as a diagnostic aids in patients with unexplained syncope. We studied to define the usefulness of various diagnostic test in the evaluation of patients with recurrent syncope, to assess the usefulness of head-up tilt test in the working of syncope of unknown origin and to evaluate the clinical characteristics of subgroups of patients with syncope induced by head-up tilt test. Methods: Between June, 1991 and November, 1992 at St. Mary`s hospital, 21 patients with history of syncope and 24 control subjects without history of syncope underwent 60° head-up tild test for 60 min. Results: 1) The definite cause for recurrent syncope were diagnosed in 10 of patients (47,6%) after clinical and invasive tests. 2) During head-up tilt test, vasovagal responses were provoked in 5 of 21 patients (23.8%) with recurrent syncope and 1 of 24 patients (4.2%) without syncope (p<0,05). 3) The head-up tilt test induced symptomatic bradycardia or hypotension in 3 of 10 patients (30%.) with negative electrophysiologic results. 4) During tilt induced vasovagal response, a) mean heart rate decreased to 42±24 beat/min from supine control of 70±12 beat/min (p<0. 05), b) mean systolic blood pressure decreased to 95±12 mmHg from supine control of 120±S mmHg (p<0,05), c) mean diastolic blood pressure decreased to 60±21mmHg from supine control of 72±13 mmHg (p<0.05), d) the time interval to onset of vasovagal response was 22±12 min. Conclusions: 1) In a large proportion of patients with recurrent syncope, the diagnosis remains unexplained despite a neurologic and cardiologic investigation including an electrophysiologic study. 2) Vasovagal responses are frequent cause in patients with recurrent unexplained syncope. 3) The head-up tilt test may be a simple, safe and highly yielding provocative test in the investigation of syncope of unknown origin.

Improved UV response of ZnO nanotubes by resonant coupling of anchored plasmonic silver nanoparticles

Biswas, Pranab,Cho, Seong Rae,Kim, Jong-Woo,Baek, Sung-Doo,Myoung, Jae-Min IOP 2017 Nanotechnology Vol.28 No.22

<P>In this study, plasmonic silver (Ag) nanoparticle-(NP) anchored ZnO nanorods (NRs) and nanotube-(NT) based UV photodetectors are demonstrated. Here, Ag NPs are synthesized and anchored by using a room-temperature photochemical method by exposing the precursor solution in UV radiation. In order to achieve a stronger surface plasmon resonance (SPR) and minimum agglomeration, the photochemical method is optimized with a precursor concentration of 5 mmol, a UV intensity of 0.4 mWаиаcm<SUP>−2</SUP>, and an exposure time of 30 min. An asymmetry around 380 nm in the absorption spectra of the NP solution indicates the presence of plasmonic resonance in that region. Upon anchoring the Ag NPs, ZnO NRs show enhanced band edge emission (380–400 nm) and the emission is further significantly increased in Ag NP-anchored ZnO NTs. The on/off ratio and photoresponse properties of the UV photodetectors are enhanced significantly after anchoring Ag NPs on the ZnO nanostructures. It is believed that the near-field coupling of SPR causes an optical enhancement of ZnO, whereas the bridging effect and hot-electron transfer to the conduction band of ZnO by plasmonic Ag NPs, anchored in close proximity, gives rise to a faster response of the photodetectors.</P>

OB-21 : Frontal lobe and cerebellar differences in IUGR and AGA fetuses

( Min Young Park ),( Kyung Won Shim ),( Ju Won Baek ),( Hyun Ji Kim ),( Sun Hwa Im ),( Mi Young Kim ),( Mi Na Byon ),( Eun Ju Lee,),( Seung Su Han ),( Sang Hoon Lee ),( Dong Ho Kim ),( Hyoung Moo Park 대한산부인과학회 2014 대한산부인과학회 학술대회 Vol.100 No.-

목적: Children with history of intrauterine growth restriction (IUGR) have shown abnormal neurological tests or cognitive functions. The pathophysiologic event in utero is not known. Uneven preferential intracranial blood supply can be related. We tried to find the causative phenomenon in fetal brain of severe IUGR. 방법: A prospective ultrasound evaluation of 100 pregnant women was conducted between 18 to 38weeks` gestation between 25 April 2013 and 1 July 2013 in Chung-Ang University Hospital. A group of 7 severe IUGR (defined as an estimated fetal weight <3th centile) , 6 IUGR (estimated fetal weight <10th centile) and 87 AGA fetuses by gestational age were studied. Ultrasound examination for fetal standard fetal biometry, including biparietal diameter (BPD), head circumference(HC), abdominal circumference (AC), femur length, the frontal lobe distance (posterior cavum septum pellucidum to the inner calvarium) and transcerebellar diameter (TCD) were measured in patients. All pregnancies had certain dates. Ratio between frontal lobe distance and TCD were calculated. Differences in ratios between IUGR and AGA fetuses were analyzed Student T-test. 결과: Significant differences (p<0.03) were found in the frontal lobe diameter/ TCD ratio between severe IUGR (0.54) and AGA fetuses (0.62). According to severity of IUGR, frontal lobe diameter showed significant differences (p<0.05). Severe IUGR fetuses (1.4cm) had smaller frontal lobe diameter than IUGR fetuses (1.7cm). However, statistically significant differences of TCD could not found among three groups . 결론: This study shown that in early onset IUGR fetuses, frontal lobe diameter was reduced, but cerebellar diameter was preserved. Under restricted blood supply such as in severe IUGR, growth of frontal lobe is sacrificed first than cerebellar growth. Sonographic measurement of frontal lobe and cerebellar diameter of IUGR fetuses might be useful tool to screen out future neurologic development after birth.

A Study on a Radar Absorbing Structure for Aircraft Leading Edge Application

Baek, Sang Min,Lee, Won Jun,Joo, Young Sik The Korean Society for Aeronautical and Space Scie 2017 International Journal of Aeronautical and Space Sc Vol.18 No.2

An electromagnetic (EM) wave absorber reduces the possibility of radar detection by minimizing the radar cross section (RCS) of structures. In this study, a radar absorbing structure (RAS) was applied to the leading edge of a blended wing body aircraft to reduce RCS in X-band (8.2~12.4GHz) radar. The RAS was composed of a periodic pattern resistive sheet with conductive lossy material and glass-fiber/epoxy composite as a spacer. The applied RAS is a multifunctional composite structure which has both electromagnetic (EM) wave absorbing ability and load-bearing ability. A two dimensional unit absorber was designed first in a flat-plate shape, and then the fabricated leading edge structure incorporating the above RAS was investigated, using simulated and free-space measured reflection loss data from the flat-plate absorber. The leading edge was implemented on the aircraft, and its RCS was measured with respect to various azimuth angles in both polarizations (VV and HH). The RCS reduction effect of the RAS was evaluated in comparison with a leading edge of carbon fabric reinforced plastics (CFRP). The designed leading edge structure was examined through static structural analysis for various aircraft load cases to check structural integrity in terms of margin of safety. The mechanical and structural characteristics of CFRP, RAS and CFRP with RAM structures were also discussed in terms of their weight.

Comparative serology of human brucellosis in Korea

( Sung Il Lee ),( Min Jung Choi ),( Jin Hur ),( Md Ariful Islam ),( Mst Minara Khatun ),( Byeong Kirl Baek ),( Chang Seup Lee ),( Ibulaimu Kakoma ),( Stephen M Boyle ),( Nammalwar Sriranganathan ),( E 한국가축위생학회 2008 韓國家畜衛生學會誌 Vol.31 No.3

The study was carried out to evaluate the diagnostic efficacy of the tube agglutination test(TAT), enzyme-linked immunosorbent assay(ELISA) and the 2-Mercaptoethanol agglutination test(2-MAT) to detect human brucellosis patients in Korea. We examined 87 serum samples of people in the rural farm areas where bovine brucellosis had been reported. People in this study were divided into seven groups- farmers and their families, veterinarians, veterinary quarantine workers, livestock health control officers, artificial inseminators, livestock traders and healthy control individuals. Among 87 people, 65 were males and 22 were females ranging in age from 13 to 72 years. Of 87 serum samples, ELISA detected 21.84%, TAT detected 11.50% and 2-MAT detected 8.05% Brucella positive sera. Brucella specific IgG ELISA antibody titer was recorder higher in the individuals between the ages of 50 and 65 years. The highest prevalence rate of brucellosis(29.4%) was recorded in the cattle farmers and their family members followed by quarantine veterinary office workers(25%) and practicing veterinarians(11.1%). The majority of the Brucella sero-positive individuals in this study had a history of direct contact with animals.

Power-Efficient Fast Write and Hidden Refresh of ReRAM Using an ADC-Based Sense Amplifier

Sang-Yun Kim,Jong-Min Baek,Dong-Jin Seo,Jae-Koo Park,Jung-Hoon Chun,Kee-Won Kwon IEEE 2013 IEEE transactions on circuits and systems. a publi Vol.60 No.11

<P>An ADC-based current-mode sense amplifier and its usage to improve speed, power efficiency, and reliability of ReRAM are proposed. The adaptive step-size control of incremental step pulse programming enables 2.25 times faster write with 50% power. The degradation of ReRAM cells due to aging can be recovered by hidden refresh without sacrificing system performance. The test circuits are fabricated using a 350-nm technology and integrated with a 1-Kb HfOx array chip.</P>

Prevalence and genetic characterization of respiratory syncytial virus (RSV) in hospitalized children in Korea.

Baek, Yun Hee,Choi, Eun Hye,Song, Min-Suk,Pascua, Philippe Noriel Q,Kwon, Hyeok-il,Park, Su-Jin,Lee, Jun Han,Woo, Sung-Il,Ahn, Byung-Hoon,Han, Heon-Seok,Hahn, Yoon-Soo,Shin, Kyeong-Seob,Jang, Hae-Lan Springer-Verlag 2012 Archives of virology Vol.157 No.6

<P>Human respiratory syncytial virus (HRSV) is the most common respiratory pathogen among infants and young children. To investigate the prevalence and genetic characteristics of HRSVs circulating in South Korea, we analyzed medical records of patients and performed molecular analysis of the G-protein gene of viruses detected from nasopharyngeal aspirates (NPA) of admitted patients at the Pediatrics Department of Chungbuk National University Hospital from April 2008 to April 2010. Epidemiological data revealed that the prevalence of HRSV infection was high during both winter seasons (October 2008 to February 2009 and November 2009 to February 2010). Of the 297 positive NPA specimens from infants or children tested, 67% were identified as HRSV-A while 33% were HRSV-B. The HRSV subgroup B was the most dominant in December 2008, but its dominance was dramatically replaced by HRSV subgroup A strains by February 2009. Phylogenetic analysis of the G protein sequences of HRSVs revealed novel genotypes within the HRSV-A (genotype CB-A) and B (genotypes BA11 and CB-B) subgroups in South Korea in addition to other strains identified in other countries. Molecular analysis also revealed genetic variability at the C-terminal end of the G proteins of the two HRSV subgroups, suggesting selection pressure in this region, which may potentially impact immune recognition. This is the first report of these HRSV variants in South Korea, indicating active genetic evolution of HRSV strains. Therefore, this study provides information on the molecular epidemiology of current HRSVs in the country and presents data for comparative analysis with other HRSV strains circulating worldwide.</P>

Substance P blocks the impairment of paracrine potential of MSC due to long term culture

Sang Min Baek,손영숙,Hyun Sook Hong 대한독성 유전단백체 학회 2018 Molecular & cellular toxicology Vol.14 No.3

Backgrounds: Transplantation of mesenchymal stem cells (MSCs) has been considered a novel cell therapy for diverse diseases. MSCs exert their effect through multi-lineage differentiation, immunosuppression, and anti-apoptosis, as proven in diseases like diabetes or rheumatoid arthritis. However, transplantation of MSCs has some limitations; donor age plays an important role in determining their therapeutic activity. Aged MSCs have low proliferative and paracrine potential. Moreover, long-term culture in vitro triggers cellular senescence. Thus, a strategy to enhance cellular activity and block senescence during ex vivo culture is needed to develop efficacious MSC-based therapies. Methods: In this study, we examined the beneficial role of Substance P (SP) on paracrine activity in human bone marrow-derived MSCs from young or aged donors. During ex vivo culture, MSCs were treated with SP and their proliferation rates, cumulative cell numbers, cytokine profiles, and multi-differentiation abilities were analyzed. Results: In MSCs derived from young donors, longterm culture inhibited proliferation and cytokine secretion (TGF-β and VEGF), which were alleviated by the addition of SP. SP had a marked positive effect on the activity of aged MSCs. Conclusion: Collectively, SP can block the loss of therapeutic potential of MSCs by preserving their proliferative and paracrine potential. This study indicates the potential of SP as a supplement in stem cell culture for therapy.