• Journal of Microbiology and Biotechnology
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• v.30 no.3
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• pp.469-475
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• 2020

During meiosis I, programmed DNA double-strand breaks (DSBs) occur to promote chromosome pairing and recombination between homologs. In Saccharomyces cerevisiae, Mec1 and Tel1, the orthologs of human ATR and ATM, respectively, regulate events upstream of the cell cycle checkpoint to initiate DNA repair. Tel1^ATM and Mec1^ATR are required for phosphorylating various meiotic proteins during recombination. This study aimed to investigate the role of Tel1^ATM and Mec1^ATR in meiotic prophase via physical analysis of recombination. Tel1^ATM cooperated with Mec1^ATR to mediate DSB-to-single end invasion transition, but negatively regulated DSB formation. Furthermore, Mec1^ATR was required for the formation of interhomolog joint molecules from early prophase, thus establishing a recombination partner choice. Moreover, Mec1^ATR specifically promoted crossover-fated DSB repair. Together, these results suggest that Tel1^ATM and Mec1^ATR function redundantly or independently in all post-DSB stages.

• Korean Journal of Pharmacognosy
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• v.33 no.4 s.131
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• pp.308-311
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• 2002

Advanced glycation end products(AGEs) are largly involved in the pathogenesis of diabetic nephropathy. It is obvious that inhibition of AGEs formation is important in preventing the occurrence and progression of diabetic nephropathy. In diabetes, this reaction is greatly accerated and is important in the pathogenesis of diabetic complications, especially diabetic nephropathy. Therefore, to seek possible AGEs inhibitors in herbal medicines, unprocessed - and processed Magnolia Bark were examined in vitro as basic data for aniaml experiment. The content of magnolol in unprocessed Magnolia Bark was $0.796{\pm}0.072%$, and after processing was decreased to $0.586{\pm}0.101%(p<0.01)$. The content of AGEs was measured by their intrinsic fluorescence. The $IC_{50}({\mu}g/ml)$ values of aminoguanidine, unprocessed- and procesled Magnolia Bark are $38.845{\pm}8.36{\mu}g/ml$, $54.264{\pm}3.153{\mu}g/ml$ and $27.882{\pm}1.836{\mu}g/ml$, respectively. This result means that prcessed Magnolia Bark was more effective than aminoguanidine, as positive control.

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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• pp.63-63
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• 2003

$\alpha$$_1$-Antityrpsin is a member of the serine protease inhibitor (SERPIN) family that shares a common tertiary structure. The reactive site loop (RSL) of serpins is exposed at one end of the molecule for protease binding. Upon cleavage by a target protease, the RSL is inserted into the major $\beta$-sheet A, which is a necessary process for formation of a tight inhibitory complex. Various biochemical and structural studies suggest that the rate of the RSL insertion upon binding a target protease is critical for inhibitory activity, and it is thought that helix F region (thFs3A and helix F) located in front of $\beta$-sheet A, should be lifted for the loop insertion during complex formation.

• Journal of Periodontal and Implant Science
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• v.36 no.1
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• pp.1-14
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• 2006

The purpose of the present study was to evaluate the histologic results of bone cavities that were surgically created in the calvaria of rabbit and filled with $HA/{\beta}-TCP$ composite powders, which had been developed in Korea (Dentium, Korea). Ten young adult rabbits were used. Four defects were surgically produced in calvaria of each rabbit. Each rabbit was anesthetized with Ketamine-HCI (5 mg/kg, Yuhan Cor. Korea) and Xylazine-HCI (1.5 ml/kg, Yuhan Cor. Korea)). An incision was made to the bony cranium and the periosteum was reflected. Using a trephine bur (external diameter: 8 mm, 3i, USA), 4 'through-and-through' bone defects were created with copious irrigation, and classified into 4 groups: control group: no graft materials, experimental group I: normal saline + graft materials: experimental group II: venous blood + graft materials: experimental group III: graft materials only. The defects were randomly filled with graft materials. The defects were closed with resorbable suture material. At the end of the surgical procedure, all animals received a single intramuscular injection of antibiotics Gentamicin (0.1 mg/kg, Dae Sung Microb. Korea). Rabbits were sacrificed with phentobarbital (100 mg/kg) intravenously at 1-, 2-, 4-, 6- and 8-week after. Specimens were treated with hydrochloric acid decalcifying solution (Fisher Scientific, Tustin, CA) and sectioned by bisecting the 8 mm diameter defects. The histologic specimens were prepared in the general method with H & E staining at 6 ${\mu}m$ in thickness. The results were as follows; 1. New bone formation showed from after 2-week of surgery in defect area. As time lapsed, lots of new bone formation and mature bones showed. 2. Histologically, degree of new bone formation could not be discerned among the experimental groups. But, for experimental group II, lots of cells gathered around graft materials after 1-week of surgery, new bone formed slightly faster and than the others at 1-week after. For experimental group I, a few inflammatory finding showed around graft material at after 1-week and after 2-week of surgery. 3. No bone formation did show for control group. Based on histologic results, the new $HA/{\beta}-TCP$ composite powders appeared to act as a scaffolding material for regeneration of osseous defects.

• Journal of the Korean Society of Radiology
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• v.16 no.5
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• pp.559-565
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• 2022

In this study, we intend to develop a granulation tissue formation model. As a pilot experiment, a contrast agent was injected into the pylorus in 3 rats, the normal pylorus lumen size was confirmed, and a stent was placed. Stent migration was confirmed in to the duodenum within 1 week. In this experiment, stent was sutured and fixed to induce granulation tissue formation after gastrostomy under a fluoroscopic guidance. Twenty rats were divided into Healthy Group / Gastrostomy Group. After anesthesia of the Gastrostomy Group, an abdominal incision was performed, and gastrostomy was performed under a fluoroscopic guidance, and a stent was placed into the pylorus. In order to prevent stent migration due to peristalsis, suture between the pylorus and the proximal end of the stent was performed. Postoperative behavior and weight changes were monitored daily. Four weeks after surgery, gastrointestinal fluoroscopy imaging was performed and rats were sacrifices. To evaluate the degree of granulation formation, the stent was sectioned transversely. Gastrostomy group was statistically significantly higher than Healthy Group in granulation area ratio (all p<.001). In conclusion, it is considered that the level of tissue overgrowth formation for preclinical evaluation of the pylorus stricture model through gastrostomy is appropriate as a research evaluation tool.

• Journal of the Korean Chemical Society
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• v.5 no.1
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• pp.42-47
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• 1961

A titration of a small amount of iron with standard potassium ferrocyanide using potassium thiocyanate as indicator has been studied. A sample solution containing $0.1{\sim}1.0$ mg. $Fe^{3+}$ in 60 ml. is pipeted into 100 ml. Erlenmyer flask and the pH of the solution is adjusted to $1.5{\sim}3.0$ with 0.1 N or 1 N $HNO_3$ and $NH_4OH.$ To this solution one ml. of 1 M KCNS solution as indicator is added. The solution colored by iron thiocyanate complex is titrated with 1/200 M or 1/400 M standard solution of potassium ferrocyanide from a 5 ml. micro-buret. Near the end point, when the color of sample changes from deep red to green, about 20 ml. of ether is added and shake the flask vigorously. The red color is extracted to the ether layer. To settle the ether layer a few drops of ethanol is added and then standard solution is added dropwise and shake vigorously. The end point is reached when the color of the ether layer disappears owing to the quantitative formation of $Fe_4[Fe(CN)_6]_3.$ In this titration, 0.lmg. of $Fe^{3+}$ can be determined within 1.0% of titration error, provided the following optimum conditions, i.e., pH $1.5{\sim}3.0$, final concentration of KCNS indicator; $0.01{\sim}0.02M$, at room temperature. The titration found to be interfered by the presence of slightly soluble salts, stable complex forming ions and the ions which would be reduced by ferrocyanide or oxidized by ferric ion.

• Journal of The Korean Astronomical Society
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• v.44 no.6
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• pp.217-234
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• 2011

We present two large cosmological N-body simulations, called Horizon Run 2 (HR2) and Horizon Run 3 (HR3), made using $6000^3$ = 216 billions and $7210^3$ = 374 billion particles, spanning a volume of $(7.200\;h^{-1}Gpc)^3$ and $(10.815\;h^{-1}Gpc)^3$, respectively. These simulations improve on our previous Horizon Run 1 (HR1) up to a factor of 4.4 in volume, and range from 2600 to over 8800 times the volume of the Millennium Run. In addition, they achieve a considerably finer mass resolution, down to $1.25{\times}10^{11}h^{-1}M_{\odot}$, allowing to resolve galaxy-size halos with mean particle separations of $1.2h^{-1}$Mpc and $1.5h^{-1}$Mpc, respectively. We have measured the power spectrum, correlation function, mass function and basic halo properties with percent level accuracy, and verified that they correctly reproduce the CDM theoretical expectations, in excellent agreement with linear perturbation theory. Our unprecedentedly large-volume N-body simulations can be used for a variety of studies in cosmology and astrophysics, ranging from large-scale structure topology, baryon acoustic oscillations, dark energy and the characterization of the expansion history of the Universe, till galaxy formation science - in connection with the new SDSS-III. To this end, we made a total of 35 all-sky mock surveys along the past light cone out to z = 0.7 (8 from the HR2 and 27 from the HR3), to simulate the BOSS geometry. The simulations and mock surveys are already publicly available at http://astro.kias.re.kr/Horizon-Run23/.

• Membrane Journal
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• v.29 no.3
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• pp.147-154
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• 2019

The permeate flux increments of a natural convection instability flow (NCIF) caused by the change of inclined angles ($0{\sim}180^{\circ}$) to gravity of the commercial membrane module were tested in the dead-end membrane filtration of BSA protein solution. The NCIF are more generated as the inclined angle increased from $0^{\circ}$ to $180^{\circ}$, and the occurred NCIF enhances permeate flux. However, the commercial module can only generate NCIF by completely removing the air gap in module. Since the custom design module designed in this study is permeated in a crossward direction ($90^{\circ}$), NCIF is always generated even if there is the air gap in module. The results of membrane filtration of BSA and dextran solutions using a custom design module showed that the flux in the crossward direction is increased to about 3.8 times for BSA solution and 1.8 times for dextran solution after two hours of operation due to the occurrence of NCIF. Also, NCIF generation is continued during 20 hours filtration of BSA solution, increasing the permeate flux to about 7.5 times. Since the custom design module with a permeation in the crossward direction and NCIF is always generated within the module, so it is possible to expect an increase in permeate flux due to the suppression of fouling formation, and thus to be utilized as a superb dead-end membrane module.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.4
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• pp.175-182
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• 1998

Recently it is reported that anomalously low saline surface waters (salinity < 32) occurred at the Ulleung Basin in the East Sea-Japan Sea, during early September to November 1996. Apparent source of such a low saline watermass seems remotely linked to the Changjiang Dilute Water (CDW), which expands to the vicinity of Cheju Island during a flood season. Based on the assumption that waters passing through the Western Channel of the Korea Strait are formed by a mixing of Kuroshio Water and CDW, simplified two end-member mixing model using $^{228}Ra/^{226}Ra$ as a conservative tracer is applied to calculate the contribution of each end member for the formation of low saline surface seawater. Model calculations show CDW contributes $58{\pm}3%$ in September 1996 (S=32.17) and $10{\pm}3%$ in February 1997 (S=34.53) in the formation of surface water flowing into the Western Channel of the Korea Strait. Although results arc deduced from a simplified model with limited data, this study demonstrates that Changjiang discharge is clearly traceable to the interior of the East Sea-Japan Sea in fall season. Undergoing Three Valley Dam construction in the Changjiang River would invoke inevitable changes in the nature and discharge of CDW and its impacts on the marine environment might be significant in the northern East China Sea and even in the Ulleng Basin for coming decades.

• Restorative Dentistry and Endodontics
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• v.39 no.4
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• pp.276-281
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• 2014

Objectives: The purpose of this study was to compare the cutting efficiency of a newly developed microprojection tip and a diamond-coated tip under two different engine powers. Materials and Methods: The apical 3 mm of each root was resected, and root-end preparation was performed with upward and downward pressure using one of the ultrasonic tips, KIS-1D (Obtura Spartan) or JT-5B (B&L Biotech Ltd.). The ultrasonic engine was set to power-1 or -4. Forty teeth were randomly divided into four groups: K1 (KIS-1D / Power-1), J1 (JT-5B / Power-1), K4 (KIS-1D / Power-4), and J4 (JT-5B / Power-4). The total time required for root-end preparation was recorded. All teeth were resected and the apical parts were evaluated for the number and length of cracks using a confocal scanning micrscope. The size of the root-end cavity and the width of the remaining dentin were recorded. The data were statistically analyzed using two-way analysis of variance and a Mann-Whitney test. Results: There was no significant difference in the time required between the instrument groups, but the power-4 groups showed reduced preparation time for both instrument groups (p < 0.05). The K4 and J4 groups with a power-4 showed a significantly higher crack formation and a longer crack irrespective of the instruments. There was no significant difference in the remaining dentin thickness or any of the parameters after preparation. Conclusions: Ultrasonic tips with microprojections would be an option to substitute for the conventional ultrasonic tips with a diamond coating with the same clinical efficiency.