• Journal of Hydrogen and New Energy
• /
• v.17 no.4
• /
• pp.371-378
• /
• 2006

Effect of $(NH_4)_2SO_4$ precipitation and heat-treatment on hydrogenase which was extracted from the cytoplasmic fraction of the phototrophic purple sulfur bacterium Thiocapsa roseopersicina NCIB 8347 was studied. Crude enzyme extract was prepared by centrifugation($28,000{\times}g$, $400,000{\times}g$) after sonication of cells grown under photosynthetic condition for 96 hrs. Various conditions of $(NH_4)_2SO_4$ precipitation and heat-treatment were examined and the effect of protein concentration was analyzed by SDS-electrophoresis between the treatments. Optimum conditions for $(NH_4)_2SO_4$ precipitation and heat-treatment for evolution hydrogenase activity were 40-60% saturation and $60^{\circ}C$ for 20 min, respectively, which exhibited the specific hydrogenase activity of 0.78 U/mg-protein. Specific hydrogenase activity was decreased to 31.6% when the heat-treatment at $60^{\circ}C$ increased from 20 min to 5 hrs.

• Journal of Technologic Dentistry
• /
• v.33 no.1
• /
• pp.47-54
• /
• 2011

Purpose: To investigate shear bonding strength between dental zirconia ceramics with different surface treatment and metal bracket. Methods: Zirconia ceramics(LAVA, 3M ESPE, USA) were divided to 4 groups according to their surface treatment; no surface treatment(G1), sand blasting(G2), silane coating(G3), and sand blasting+silane coating(G4). Specimens were bonded to metal bracket using resin bond($Transbond^{TM}XT$, 3M Unitek, USA). Shear bond strength was measured using universal test machine(3366 INSTRON. U.S.A) with cross head speed of 1 mm/min. Microstructural investigation for fracture surface was performed after shear test. Results: Shear bonding strengths of single surface treatment groups (G2 and G3) were higher than no treatment group(G1). Combined Treatment Group (G4) showed the highest shear bond strength of 9.15MPa. Microstructural observation shows that higher shear bonding strength was obtained when debonding was occurred at metal bracket/resin interface rather than zirconia ceramic/resin interface. Conclusion: Surface treatment of zirconia is necessary to obtain higher bonding strength. Combined treatment can be more effective when surface the surfaces are kept clean and homogeneous.

• Animal Systematics, Evolution and Diversity
• /
• v.22 no.2
• /
• pp.223-229
• /
• 2006

Two litonotid ciliates collected from the freshwater habitats in Korea were identified as Loxophyllum meleagris ($M\ddot{u}ller$, 1773) and Siroloxophyllum utriculariae (Penard, 1922). The description was based on the observation of living and protargol impregnated specimens, and biometric analysis. Their diagnostic characteristics are as follows. L. meleagris; $163-480\times80-100{\mu}m$ in vivo, body shape lancet or knife-like; dorsal margin with 10-19 extrusome warts; 8-35 macronuclei nodules, like a string of bead; 16-21 somatic kineties on right side (including perioral kinety 2, 3) and 6-11 on left side (including perioral kinety 1); 1 contractile vacuole located at posterior part at diastole stage, extending along the dorsal margin toward anterior end with a single long narrow canal. S. utriculariae; $110-170\times78-150{\mu}m$ in vivo, body shape lancet like; dorsal margin without extrusome warts; 2 macronuclei, spherical; 12-19 somatic kineties on right side, 3-7 on left side (including perioral kinety 1); 2-3 contractile vacuoles, first one located anterior ventrally, second one located posterior dorsally and last one located near posterior end of cell.

• Korean journal of food and cookery science
• /
• v.26 no.5
• /
• pp.530-536
• /
• 2010

This study was the tenderizing activity of fig and kiwifruit using meat cooking. Furthermore, the effects of various seasonings and flavor spices were investigated. The proteolytic activity of kiwifruit was 36,513 uM/g fruit, whereas that of fig was 24,131 uM/g fruit. The best amount of fruit for meat cooking was 3~5% for kiwifruit and 5% for fig among three different dilutions, 3%, 5% & 10%. The effect of fruit ratio showed that treatment with 'kiwifruit only' produced the best organoleptic results, and there was no significant difference between the kiwifruit and fig ratios, 3:0, 2:1, 1:1. The best marinating time for meat tenderizing by fig and kiwifruit was 6hr at $4^{\circ}C$. The best marinating temperature for meat tenderizing by fig and kiwifruit was $25^{\circ}C$ rather than $4^{\circ}C$. Fruit sauce containing basic seasonings such as soy sauce, sugar, oligosaccharides, and sesame oil had a pH of 4.64 for fig and 4.23 for kiwifruit. The addition of soy sauce, oligosaccharides, and rice wine decreased the proteolytic activity of the fruits. Fruit sauce containing basic seasonings, garlic, ginger, onion and scallion had a pH of 4.71 for fig and 4.43 for kiwifruit. Finely chopped garlic, finely chopped scallion, and pureed onion, finely chopped ginger, and pear juice, all increased the proteolytic activity of the fruits. There the fruit sauce containing seasonings and flavory spices for meat cooking improved the tenderness and preference in terms of sensory evaluation without undesirable taste or increased fruits.

• Clinical and Experimental Reproductive Medicine
• /
• v.38 no.4
• /
• pp.222-227
• /
• 2011

Objective: To evaluate the ability of serum anti-M$\ddot{u}$llerian hormone (AMH), FSH, and age to clinically predict ovarian response to controlled ovarian hyperstimulation (COH) in IVF patients with endometriosis. Methods: We evaluated 91 COH cycles, including 43 cycles with endometriosis (group I) and 48 cycles with male factor infertility (group II) from January to December, 2010. Patients were classified into study groups based on their surgical history of endometriosis-group Ia (without surgical history, n=16), group Ib (with a surgical history, n=27). Results: The mean age was not significantly different between group I and group II. However, AMH and FSH were significantly different between group I and group II ($1.9{\pm}1.9$ ng/mL vs. $4.1{\pm}2.9$ ng/mL, $p$ <0.01; $13.1{\pm}7.2$ mIU/mL vs. $8.6{\pm}3.3$ mIU/mL, $p$ <0.01). Furthermore, the number of retrieved oocytes and the number of matured oocytes were significantly lower in group I than in group II. In group II, AMH and FSH as well as age were significant predictors of retrieved oocytes on univariate analysis. Only the serum AMH level was a significant predictor of poor ovarian response in women with endometriosis. Conclusion: Serum AMH may be a better predictor of the ovarian response of COH in patients with endometriosis than basal FSH or age. AMH level can be considered a useful clinical predictor of poor ovarian response in endometriosis patients.

• Korean Journal of Health Education and Promotion
• /
• v.26 no.5
• /
• pp.115-127
• /
• 2009

Objectives: To compare alcohol secondhand effects among US and Korean students. Methods: Nationally representative 4-year colleges of two countries were involved in this cross-national comparison study. Data from the 2001 U.S. College Alcohol Study and the 2003 Korean College Alcohol Study came from 120 colleges in 38 U.S. states and the District of Columbia and 60 colleges in Korea. Randomly selected 4-year college students from the U.S. (10,924) and Korea (2,385) participated in the study using self-reports of alcohol use and perceptions of drinking as assessed by College Alcohol Study questionnaires. Results: Korean students were tend to more likely to have being a victim of sexual assault or date rape, having to take care of drunken students and finding vomit in the hall or bathroom of residence, than US students, while US students were tend to more likely to have being insulted or humiliated, having a serious argument and quarrel, being pushed, hit, or assaulted, having study/sleep interrupted, and experiencing an unwanted sexual advance than Korean students. Conclusion: In general, US students were more likely to suffer interrelationship problems after drinking while Korean students were more likely to have physical and individual drinking related problems.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.44 no.8
• /
• pp.1157-1164
• /
• 2015

The present investigation evaluated the antioxidant activities of water extracts from dandelion (Taraxacum officinale) aerial parts, roots, and mixed extracts. Mixed extract of T. officinale was a mixture of aerial parts and roots at 9:1 and 8:2 weight ratios. Extracts from aerial parts (DAE), roots (DRE), and mixture of aerial parts and roots (DME) were measured for cell viability and catalase activity in HepG2 cells, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, and lipid peroxidation inhibitory activity. Cell viabilities of HepG2 cells treated with DAE, DRE, DME 8:2, and DME 9:1 against $H_2O_2$-induced oxidative damage were 63.4%, 54.6%, 76.7% and 83.4% at a concentration of $400{\mu}g/mL$, respectively. Catalase activity was highest in DME 9:1 (12.2 mU/min/mg protein) compared with DAE (9.0 mU/min/mg protein) and DRE (9.7 mU/min/mg protein). DPPH radical scavenging activity of DME showed a significantly lower $EC_{50}$ value than DAE ($EC_{50}$ value of DME $9:1=163.3{\mu}g/mL$, DME $8:2=172.4{\mu}g/mL$, and $DAE=173.7{\mu}g/mL$). Lipid peroxidation inhibitory activity of DME showed a significantly lower $EC_{50}$ value than DAE [$EC_{50}$ values of DME $(9:1)=454.4{\mu}g/mL$, DME $(8:2)=426.6{\mu}g/mL$, and $DAE=654.7{\mu}g/mL$]. The results indicate that a small amount of T. officinale roots increased antioxidant activity of aerial parts. Especially, a 9:1 mixture was more valuable than 8:2 mixture for industry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.12-12
• /
• 2009

We weal know that PbO was poisonous and prone to volatilize, then to pollute the circumstance and hurt to people, so we should dope other innocuous additives instead of lead to increase Tc of composite PTC material. In order to prepare lead-free $BaTiO_3$-based PTC with middle Curie point, the incorporation on $(BaNaK)(TiNb)O_3$ into $BaTiO_3$-based ceramics was investigated on samples containing 0.05, 0.07 and 0.1mol% of $(BaNaK)(TiNb)O_3$. $(BaNaK)(TiNb)O_3$ was compounded as standby material by conventional solid-state reaction technique. The starting materials were $Na_2O_3$,$K_2CO_3$, $BaCO_3$, $TiO_2$ and $Nb_2O_5$ powder, and using solid-state reaction method, too. The microstructure of samples were investigated by SEM, DSC, XRD and dielectric properties. Phase composition and lattice parameters were investigated by X-ray diffraction. Also, we are measure the resistivity of sintered bodies with calcinations condition.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.2
• /
• pp.143.2-143.2
• /
• 2012

2012년 3월 7일부터 5월 9일까지, 총 8일간 소백산 천문대의 61cm 반사망원경에 부착된 PIXIS 2K CCD와 Johnson-Cousins의 표준필터 BVRI 4색 필터를 이용하여 접촉쌍성 VW Boo의 전 위상에 걸친 광도곡선을 획득하였다. 이 관측으로부터 7개의 극심시각(주식: 4개, 부식: 3개)을 결정하였다. 우리의 극심시각을 포함하여 여러 문헌에서 수집한 총 201개의 극심시각을 이용하여 주기분석을 수행하였다. VW Boo의 주기는 약 74년에 걸쳐 영년주기감소와 규칙적인 변화를 겪은 것으로 나타났다. 영년 주기감소율은 년간 $-1.595{\times}10^{-7}$일이며, 규칙적인 변화의 주기와 반진폭은 각각 약 29.8년과 0.00667일로 산출되었다. 영년주기감소를 질량이 큰 주성에서 반성으로의 질량이동에 의한 것으로 가정하였을 때, 그 질량이동율은 년간 $-1.26{\times}10^{-7}M_{\odot}/yr$이다. 규칙적인 변화를 제3천체에 의한 광시간 효과로 가정하여 구한 3천체의 최소 질량은 $0.19M_{\odot}$이다. Wilson-Devinney 쌍성 모형을 이용하여 우리의 BVRI 광도곡선을 분석하였다. 이 때, 광도곡선에 나타난 역 O'Connell 효과를 설명하기 위하여 흑점모형을 도입하였고, W형과 A형의 두 가지 경우를 상정하여 광도곡선 해를 산출하였다. 그 결과의 천체물리학적 의미를 논의한다.

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.110.3-111
• /
• 2003

In the previous studies, we have reported that NQ30l, a synthetic l,4-naphthoquinone derivative, displayed a potent antithrombotic activity, and that this might be due to antiplatelet effect, which was mediated by inhibition of cytosolic $Ca^{2+}$ mobilization in activated platelets. In the present study, the effect of NQ301 on arachidonic acid cascade in activated platlets was examined. NQ301 concentration-dependently inhibited washed rabbit platelet aggregation induced by collagen (10 $\mu$g/ml), arachidonic acid (100 $\mu$M) and U46619 (1 $\mu$M), a thromboxane $A_2$receptor agonist, with $IC_50$ values of 0.60$\pm$0.02, 0.79$\pm$0.04 and 0.58$\pm$0.04 $\mu$M, respectively. (omitted)