• Restorative Dentistry and Endodontics
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• v.36 no.5
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• pp.425-430
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• 2011

Objectives: This in vitro study investigated whether short-term application of calcium hydroxide in the root canal system for 1 and 4 wk affects the fracture strength of human permanent teeth. Materials and Methods: Thirty two mature human single rooted mandibular premolars in similar size and dentin thickness without decay or restorations were hand and rotary instrumented and 16 teeth vertically packed with calcium hydroxide paste and sealed coronally with caviton to imitate the endodontic procedure and the other 16 teeth was left empty as a control group. The apicies of all the samples were sealed with resin, submerged in normal saline and put in a storage box at $37^{\circ}C$ to mimic the oral environment. After 1 and 4 wk, 8 samples out of 16 samples from each group were removed from the storage box and fracture strength test was performed. The maximum load required to fracture the samples was recorded and data were analysed statistically by the two way ANOVA test at 5% significance level. Results: The mean fracture strengths of two groups after 1 wk and 4 wk were similar. The intracanal placement of calcium hydroxide weakened the fracture strength of teeth by 8.2% after 4 wk: an average of 39.23 MPa for no treatment group and 36.01 MPa for CH group. However there was no statistically significant difference between experimental groups and between time intervals. Conclusions: These results suggest that short term calcium hydroxide application is available during endodontic treatment.

• Reproductive and Developmental Biology
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• v.30 no.1
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• pp.53-58
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• 2006

The study was conducted to evaluate the effects of culture period and fusion method on the development of somatic cell nuclear transfer (SCNT) embryos reconstituted with Korean bovine fetal fibroblast cells (KbFF) and Korean bovine adult ear skin fibroblast cells (KbESF). KbFF were isolated from a day 51 Korean cattle (Hanwoo) fetus, and KbESF were isolated from a 28 month old Hanwoo calf. The cells were cultured up to 15 weeks (passage 15) in vitro for SCNT. Chamber and electrode needles were used for comparing fusion of reconstituted eggs. The doubling times of KbFF and KbESF were 17.3 hr and 24.3 hr, respectively. The fusion and cleavage rates were significantly higher in needle group (76.1 and 81.2% respectively, P<0.05) than those in chamber group. However, the blastocyst development rate was not different between both groups. Fusion and cleavage rates of NT eggs reconstituted with KbESF did not affected by passage number, however, blastocyst rates were lower in passage $1{\sim}4$ group (21.3%) than passage $5{\sim}8$ (39.4%) and $13{\sim}15$ groups (40.4%, P<0.05). Whereas, fusion rate was lower in passage $1{\sim}4$ group (61.5%) than those of passage $5{\sim}8$(75.0%) and $13{\sim}15$ (76.8%) groups, but cleavage and blastocyst rates were similar regardless of passage number in the KbFF. The results suggest that fusion method can affect the development of SCNT embryos, whereas the long term culture up to 15 passages may not affect the development of SCNT embryos.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.212-222
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• 2004

The application of acidulated phosphate fluoride gel(APF) and fluoride varnishes are the most common topical fluoride therapy. The purpose of this in vitro study was to compare the remineralization effects of two topical fluoride agents, APF gel and fluoride varnish with microtomograph and 3D image analyzer without sample preparation and chemical fixation. For the purpose of the study, the artificial caries lesion was caused on the caries-free permanent pre molar and 48 specimens were divided into three groups each containing 16 specimens No application was performed on group 1, which acted as control group. Group 2 was treated with APF gel and was removed after a minute. Group 3 was treated with the topical application of fluoride varnish and removed after 45 minutes. Each specimen was placed into a closed container with 50ml of a artificial saliva during three months and the 3D images of the remineralization area were taken using the SkyScan each month. Using the density-measuring program in V $works^{TM}$, the density value of the remineralization area was measured. The following results were obtained: 1. All groups demonstrated an increase in the density of artificial caries lesion with time. 2. The density was significantly higher in APF gel and fluoride varnish group than control group at 1 month, 2 months, 3 months after the treatment(P<0.05). 3. The difference of the density between that "prior to treatment" and that "1 month after treatment" in Group 2 and Group 3 was significantly higher than that of Group 1 and, the difference of the density between that "1 month after treatmen" and that "2 month after treatment" in Group 3 was significantly higher than that of Group 1 and 2(P<0.05). 4. The fluoride varnish was more effective after 2 and 3 months and continuous than the APF gel.

• Clinical and Experimental Pediatrics
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• v.51 no.10
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• pp.1065-1070
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• 2008

Purpose : This study aims to determine whether early closure (within 7 d) of significant patent ductus arteriosus (PDA) with indomethacin or ligation reduces neonatal morbidity when compared with delayed closure (after 7 d). Methods : Fifty-eight extremely-low-birth-weight infants admitted to the NICU of Seoul National University Hospital from April 2005 to May 2007 with PDA were studied retrospectively. Results : The mean gestational age (GA) was $26{\pm}2weeks$ (range, 23-32 wk), and the birth weight was $782{\pm}146g$ (range, 430-990 g). The delayed closure group was associated with early GA ($25.7{\pm}1.7wk$ vs $27.1{\pm}2.0wk$, P=0.013), in vitro fertilization (IVF) (55% vs 24%, P=0.017), and the absence of preeclampsia (5% vs. 34%, P=0.013). There was no difference in ductal size between the early closure and delayed closure groups. The incidence of bronchopulmonary dysplasia (95% vs 65%, P=0.012) and intraventricular hemorrhage (70% vs. 39%, P=0.027) increased in the delayed closure group. Using regression analysis adjusted for gestational age, delayed closure correlated positively with the duration of ventilator support (P=0.008), hospitalization (P=0.020), time to full enteral feeding (P<0.001), and total parenteral nutrition (P=0.010). Conclusion : Delayed closure of the hemodynamically significant patent ductus arteriosus in extremely-low-birth-weight infants is significantly related to the development of various morbidities. Thus, early closure of PDA is needed within the first week of life.

• Journal of Aquaculture
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• v.11 no.2
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• pp.213-221
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• 1998

The effects of differen concentrations of Obosan as a feed additive dietary herb were examined on survival rate, growth, feed conversion ration and condition factor in olive flounder (paralichthys olivaceus). Effectiveness of dietary Obosan with optimized concentration for 48 weeks were also observed with regard to growth performances and yields. All groups fed diets containing 0.15, 0.3 and 0.6% of Obosan revealed significantly higher survival rate than control group (P<0.05). Growth, feed conversion ratio and condition factor of olive flounder fed diets containing Obosan were considerably improved when compared to those of controls (P<0.05). The 0.3% of dietary Obosan was proven to be the optimal concentration in all parameters tested. The dietary Obosan (0.3%) for 48 weeks showed significantly higher surval rate than control (P<0.05), and also improved yields in weight gain (19.0% improvement), specific growth rate (4.8%), feed conversion ratio(13.6%) and condition factor (10.8%), significantly (P<0.05).

• Journal of Bio-Environment Control
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• v.14 no.4
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• pp.233-238
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• 2005

Growth of Campanula punctata 'Rubriflora' plantlets, as affected by three levels of photosynthetic photon flux (PPF), 70, 110, and $220{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, two levels of $CO_2$ concentration, 500 and $1,500{\mu}mol{\cdot}m^{-1}$, and two levels of number of air exchanges per hour (NAEH), 0.1 and $2.8 h^{-l}$, was studied. Explants were obtained from photomixotrophically-micropropagated plantlets. Four explants were planted in each $3.7{\times}10^{-4}m^3$ polycarbonate box containing MS basal medium and no added sucrose. Explants were cultured under cool-white fluorescent lamps for $16h{\cdot}d^{-1},\;at\;25\pm1^{\circ}C$ temperature, and $70\~80\%$ relative humidity In treatments of $2.8h^{-1}$ NAEH, a 10mm round hole made on the vessel cap was sealed with a microporous filter. For higher $CO_2$ concentrations in the culture room, $CO_2$ gas was provided from a tank of liquefied $CO_2$. Fresh and dry weights, length of the longest root, and number of leaves significantly increased with increasing PPF and especially $CO_2$ concentration. Length of the longest root, number of leaves, fresh and dry weights, and chlorophyll concentration were enhanced with increased NAEH. However, leaf area was the smallest in the $220{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}\;PPF\;2.8h^{-1}$ NAEH and especially, $1,500{\mu}mol{\cdot}mol^{-1}\;CO_2$ concentration treatment. Treatment effect became more produced with time. Overall, treatment with $220{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}\;PPF\;and\;1,500{\mu}mol{\cdot}mol^{-1}\;CO_2$ gave the most vigorous growth.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.850-856
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• 2010

An in vivo oral glucose tolerance test (OGTT) was performed on hyperglycemic male Sprague-Dawley rats to assess the effect of fruits and vegetables ($1g{\cdot}kg^{-1}$ body weight) on blood glucose levels (${\Delta}BGLs$) at different time intervals of 0, 5, 15, 30, 60, 90 and 120 min. The areas under glucose curve (${\Delta}AUCs$) were calculated at 120 min of OGTT by trapezoid method. Total phenolic content (TPC) and anti-oxidant activity (AOA) of fruits and vegetables were assayed in vitro by Folin Ciocalteu and DPPH (2, 2-diphenyl-1-picrylhydrazyl) methods, respectively. At the end of the experiment the correlations among the parameters TPC, AOA and ${\Delta}AUC$ was estimated by Pearson's correlations. Among fruit crops, tangerine, plum, grape and pear and among vegetables, blue leaf mustard, cabbage, chicory, broccoli and others exhibited significant hypoglycemic effects by reducing ${\Delta}BGLs$ with significant ${\Delta}AUC$. The effective ${\Delta}AUC$ ranged from $5548.2{\pm}462.1$ to $3823.3{\pm}282.0mg-min{\cdot}dL^{-1}$. The TPC and AOA ranged from $0.063{\pm}0.00$ to $0.913{\pm}0.14mg{\cdot}g^{-1}$ GAE and $01.05{\pm}0.08$ to $75.46{\pm}0.06%$, respectively. Overall, six fruits and fifteen vegetables exhibited higher TPC and one fruit and four vegetables exhibited higher AOA. There was a better correlation among TPC, AOA and ${\Delta}AUC$ of fruits and TPC & AOA of vegetables. We report that hypoglycemically significant fruits and vegetables investigated in this study have pharmacological importance which reduced ${\Delta}BGLs$ through insulin like activity and AOA in prevention of type-2 diabetes.

• KSBB Journal
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• v.18 no.3
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• pp.211-216
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• 2003

The removal yield of dissolved organic matter in drinking water by biological activated carbon (BAC) process was investigated. The tested processes wer raw water-AC process (BAC1), raw water-ozonation-BAC process (BAC2), and raw water-ozonation-coagulation/sedimentation-BAC process (BAC3). The amounts of organic matter was measured as dissolved organic carbon (DOC), ulta-violet radiation at 254 nm wavelength ($UV_{254}$), total nitrogen (T-N), ammonia nitrogen (NH_3$-N), and total phosphate (T-P). As a results, 30.7% DOC was removed by BAC2 process, which showed higher removal efficiency than BAC1 or BAC3 processes. The removal yield of $UV_{254}$ in BAC1, BAC2, and BAC3 processes were observed as 45.3%, 44.6%, 58.4%, respectively. And the removal yield of ammonia nitrogen were 66%, 81%, 29% in each BAC processes. The optimal empty bed contact time (EBCT) of BAC processes was estimated as 10 minute. This study has shown that BAC process combined with ozone treatment was efficient for removing dissolved organic matter in water.

• Journal of the korean academy of Pediatric Dentistry
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• v.37 no.1
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• pp.1-12
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• 2010

The aim of this study was to evaluate the preventive effect of commercially available anticariogenic products, specifically, the tooth cream containing Casein phosphopeptide-amorphous calcium phosphate(CPP-ACP), fluoride varnish and low-level fluoride mouthrinse on enamel erosion induced by carbonated beverage in a short period of time. Enamel specimens were treated as follows and were then kept in artificial saliva for 24 hours followed by further processing by alternately soaking them in Cola beverage and in distilled water for 1 minute each five times. Group 1: control group (no treatment) Group 2: tooth cream with CPP-ACP Group 3: fluoride varnish (1,000 ppm F) Group 4: low-level fluoride mouthrinse (227 ppm F) Group 5: fluoride varnish + tooth cream with CPP-ACP Group 6: low-level fluoride mouthrinse + tooth cream with CPP-ACP Microhardness and erosion depth were measured and the mineral loss of each specimen was evaluated by measuring the volumetric fluorescence change(${\Delta}Q$) against the stable fluorescent grid using quantitative light-induced fluorescence(QLF). The experiment lasted for 6 days repeated each day. The results were as follows: 1. The microhardness was increased as follows: Group $1{\leq}2{\leq}4$<6<$3{\fallingdotseq}5$. 2. The mean erosion depth was increased as follows: Group $5{\fallingdotseq}3$<6<$4{\fallingdotseq}2{\fallingdotseq}1$. 3. The ${\Delta}Q$ was increased as follows: Group $1{\fallingdotseq}2{\leq}4{\leq}6{\leq}3{\fallingdotseq}5$. The decrement of ${\Delta}Q$ was similar between group 1 and 2, group 4 and 6 and group 3 and 5. 4. The ${\Delta}Q$ showed positive correlation with microhardness (r=0.96, p<0.05), while it was negatively correlated to erosion depth (r=-0.96, p<0.05).

• Journal of Life Science
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• v.16 no.7 s.80
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• pp.1133-1140
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• 2006

Human HtrA1 (High temperature requirement protein A1) is a homologue of the E. coli periplasmic serine protease HtrA. A recent study has demonstrated that HtrA1 is a serine protease involved in processing of insulin like growth factor binding protein (ICFBP), indicating that it serves as an important regulator of IGF activity. Additionally, several lines of evidence suggest a striking correlation between proteolytic activity of HtrA1 serine protease and the pathogenesis of several diseases; however, physiological roles of HtrA1 remain to be elucidated. We used the pGEX bacterial expression system to develop a simple and rapid method for purifying HtrA1, and the recombinant HtrA1 protein was utilized to investigate the optimal conditions in executing its proteolytic activity. The proteolytically active HtrA1 was purified to approximately 85% purity, although the yield of the recombinant HtrA1 protein was slightly low $460{\mu}g$ for 1 liter E. coli culture). Using in vitro endoproteolytic cleavage assay, we identified that the HtrA1 serine protease activity was dependent on the enzyme concentration and the incubation time and that the best reaction temperature was $42^{\circ}C$ instead of $37^{\circ}C$. We arbitrary defined one unit of proteolytic activity of the HtrA1 serine protease as 200nM of HtrA1 that cleaves half of $5{\mu}M\;of\;{\beta}-casein$ during 3 hr incubation at $37^{\circ}C$. Our study provides a method for generating useful reagents to investigate the molecular mechanisms by which HtrA1 serine protease activity contributes in regulating its physiological function and to identify natural substrates of HtrA1.