• Journal of Korean society of Dental Hygiene
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• v.13 no.5
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• pp.889-900
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• 2013

Objectives : Molecular biology techniques were employed to assess diversity of bacterial in children's dental caries. Methods : DNA of germs was extracted and the diversity of the 16S rRNA clones was analyzed by amplified rDNA restriction analysis and sequencing. The experimental samples were pit and fissure caries (PC), deep dentinal caries (DC), smooth surface caries (SC), and supragingival plaque (PQ) from 50 children of age less than 12 years old. The control group was healthy teeth supragingival plaque (HT). Thirty clones from each 16S rRNA clone library of 5 samples were randomly selected, thus a total of 150 clones were analyzed. Results : Amplified rDNA restriction analysis uncovered 18, 20, 11, 17, and 22 phylotypes from healthy teeth, pit and fissure caries, deep dentinal caries, smooth surface caries, and supragingival plaque, respectively. Sequencing analysis found the dominance of Actinomycs naeslundii and Fusobacterium nucleatum in the healthy teeth; Leptotrichia sp. in the pit and fissure caries; Actinomyces sp., Streptococcus mutans, and Rahnella aquatilis in the deep dentinal caries; Streptococcus mutans and Actinomyces sp. in the smooth surface caries; Enterobacter hormaechei and Streptococcus sanguinis in the supragingival plaque. Conclusions : Clonal analysis identified 6 phyla, 20 genera, and 51 species.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.6
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• pp.155-165
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• 1998

The resistance coefficient and heat transfer performance are studied for the turbulent water flow in a smooth coiled tube having variable curvature ratios and a corrugated-coiled tube having a ratio of coil to tube diameter of 22. Experiments are carried out for the fully developed turbulent flow of water in tube coils on the uniform wall temperature condition. This work is limited to tube coils of R/a between 22 and 60 and Reynolds numbers from 13000 to 53000. The tube having a ratio of coil to tube diameter of 27 among the 3 smooth tube coils shows the best heat transfer performance. A corrugated-coiled tube(R/a=60) shows more excellent performance than a smooth coiled tub (R/a=60) at a similar curvature ratio. The friction factor f is sensitive to changes in the velocity profile caused by a temperature gradient. Allowance was made for the pressure loss in the short inlet and outlet lengths and due to the presence of the thermocouple inlet and outlet as a result of separate experimental on a straight tube. It is to be expected that the allowance at the exit will be somewhat too low because of secondary flow effects carried over from the coil.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.2
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• pp.123-129
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• 2009

Aprotinin is used clinically in cardiopulmonary bypass surgery to reduce transfusion requirements and the inflammatory response. The mechanism of action for the anti-inflammatory effects of aprotinin is still unclear. We examined our hypothesis whether inhibitory effects of aprotinin on cytokine-induced inducible nitric oxide synthase (iNOS) expression (IL-$l\beta$ plus TNF-$\alpha$), reactive oxygen species (ROS) generation, and vascular smooth muscle cell (VSMC) proliferation were due to HO-l induction in rat VSMCs. Aprotinin induced HO-l protein expression in a dose-dependent manner, which was potentiated during inflammatory condition. Aprotinin reduced cytokine mixture (CM)-induced iNOS expression in a dose dependent manner. Furthermore, aprotinin reduced CM-induced ROS generation, cell proliferation, and phosphorylation of JNK but not of P38 and ERK1/2 kinases. Aprotinin effects were reversed by pre-treatment with the HO-l inhibitor, tin protoporphyrin IX (SnPPIX). HO-l is therefore closely involved in inflammatory-stimulated VSMC proliferation through the regulation of ROS generation and JNK phosphorylation. Our results suggest a new molecular basis for aprotinin anti-inflammatory properties.

• Korean Journal of Microbiology
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• v.54 no.1
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• pp.81-83
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• 2018

We sequenced the genome of the Neisseria sp. KEM232 isolated from the smooth surface caries of human cavity of a 7-year old male in Republic of Korea by using the standard dilution plating technique. The genome comprises a single circular 2,371,912 bp chromosome with a G + C content of 58.5%, 2,210 protein-coding genes, 108 pseudo genes, 51 RNA genes, and one CRISPR array. Based on the 16S rRNA gene sequence similarity and average nucleotide identity, the strain KEM232 is most closely related to Neisseria baciliformis.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.10
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• pp.4015-4033
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• 2015

The future mobile networks consist of hyper-dense heterogeneous and small cell networks of same or different radio access technologies (RAT). Integrating mobile networks of different RATs to provide seamless and smooth mobility service will be the target of future mobile converged network. Generally, handover from high-speed networks to low-speed networks faces many challenges from application perspective, such as abrupt bandwidth variation, packet loss, round trip time variation, connection disruption, and transmission blackout. Existing inter-RAT handover solutions cannot solve all the problems at the same time. Based on the high-layer convergence sublayer design, a new receiver-aided soft inter-RAT handover is proposed. This soft handover scheme takes advantage of multihoming ability of multi-mode mobile station (MS) to smooth handover procedure. In addition, handover procedure is seamless and applicable to frequent handover scenarios. The simulation results conducted in UMTS-WiMAX converged network scenario show that: in case of TCP traffics for handover from WiMAX to UMTS, not only handover latency and packet loss are eliminated completely, but also abrupt bandwidth/wireless RTT variation is smoothed. These delightful features make this soft handover scheme be a reasonable candidate of mobility management for future mobile converged networks.

• Restorative Dentistry and Endodontics
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• v.12 no.2
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• pp.111-116
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• 1987

The experimental study was made to evaluate the influence of retentive grooves on the canal wall upon the retention of post, using different type of cements. Ninety periodontally involved anterior teeth were extracted and divided into six groups of 15 teeth. The groups were labeled as follows: Group I: Dentatus post cemented zincphosphate cement into post hole with smooth wall. Group II: Dentatus post cemented with zincphosphate cement into post hole with retentive grooves. Group III: Dentatus post cemented with glass-ionomer cement into post hole with smooth wall. Group IV: Dentatus post cemented with glass-ionomer cement into post hole with retentive grooves. Group V: Dentatus post cemented with composite resin adhesive into post hole with smooth wall. Group VI: Dentatus post cemented with composite resin adhesive into post hole with retentive grooves. The tensile strength was tested by an Instron type tester with cross-head speed of 5mm per minute. The results were as follows: In the group without retentive grooves, three kinds of cement have little effect upon retentive capacity of Dentatus post. The Dentatus post cemented on the canal wall with retentive grooves is more retentive than Dentatus post without retentive grooves.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.2
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• pp.115-121
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• 2011

The size of hydrogen molecule is not so small as to invade into the lattice of material, and therefore, hydrogen invades into the material as atom. Hydrogen movement is done by diffusion or dislocation movement in the near crack tip or plastic deformation. Hydrogen appeared to have many effects on the mechanical properties of the Cr-Mo steel alloys. The materials for this study are 1.25Cr-0.5Mo and 2.25Cr-1Mo steels used at high temperature and pressure. The hydrogen amount obtained by theoretical calculation was almost same with the result solved by finite element analysis. The distribution of hydrogen concentration and average concentration was calculated for a flat specimen. Also, finite element analysis was employed to simulate the redistribution of hydrogen due to stress gradient. The calculation of hydrogen concentration diffused into the material by finite element method will provide the basis for the prediction of delayed fracture of notched specimen. The distribution of hydrogen concentration invaded into the smooth and notched specimen was obtained by finite element analysis. The hydrogen amount is much in smooth specimen and tends to concentrate in the vicinity of surface. Hydrogen embrittlement susceptibility of notched specimen after hydrogen charging is more remarkable than that of smooth specimen.

• Journal of Ginseng Research
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• v.20 no.2
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• pp.133-138
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• 1996

Rabbit corpus cavernosal smooth muscle strips submaximally precontracted with phenylephrine (5$\times$$10^6$ M) and treated with increasing concentrations of Korean ginseng (1, 5, 10, 20, 30, 40 mg/ml) showed tension decrease concentration-dependently (1 mg/ml: 1.7%, 5 mg/ml: 10.2%, 10 mg/ml: 22.7%, 20 mg/ml: 44.0%, 30 mg/ml: 65.2%, 40 mg/ml: 95.6%). Relaxations to Korean ginseng were inhibited significantly by endothelial disruption, by pretreatment with methylene blue, pyrogallol, L-NNA and atropine. Pretreatment of the muscle strips with ginseng caused concentration-related inhibition of a phenylephrine induced contraction, and in calcium-free high potassium depolarizing solution, decreased basal tension as well as inhibited contraction induced by Caclr. Korean ginseng also produced the reduction of responses to depolarizing medium(50, 40, 60 mM KCI). With these results we can confirm the relaxation effect of ginseng at a dose dependent on the cavernosal smooth muscle and suggest that its action is mediated by multiple action mechanisms that include increasing the release of nitric oxide from the corporal sinusoids. Increasing intracellular calcium sequestration, and a hyperpolarizating action.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.1
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• pp.20-25
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• 2000

An experimental study on the condensation heat transfer coefficients of R-22, R-290 and R-600a inside horizontal tube was performed. Heat transfer measurements were performed for smooth tube with inside diameter of 10.07 mm and outside diameter of 12.07 mm and inner grooved tube having 75 fins whose height is 0.25 mm. This study was performed for condensation temperatures were from 308 K to 323 K, and mass velocity of $51 kg/m^2s - 250kg/m^2s$. The test results showed that the local condensation heat transfer coefficients increased as the mass flux increased, and also the effect of mass flow rate on heat transfer coefficients of R-290 was less than R-22. In addition, heat transfer coefficient of R-22 increased to a larger extent than R-290 and R-600a as the mass flow rate increased. Average condensation heat transfer coefficients of natural refrigerants were superior to that of R-22. The present results had a good agreement with Cavallini-Zecchin's correlation for smooth and inner grooved tubes.

• Journal of Marine Bioscience and Biotechnology
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• v.10 no.2
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• pp.53-61
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• 2018

Sargassum fulvellum (gulfweed) is a widespread seaweed in the coastal areas of northeast Asia. In the present study, we identified the phenolic compounds present in aqueous and ethanolic extracts of S. fulvellum and evaluated their antioxidative properties and their abilities to block cell proliferation using in vitro assays: antioxidant activity was assessed by using a DPPH assay and superoxide anion scavenging activity, anti-tyrosinase activity, and anti-proliferative activity were assessed using MTT and lactate dehydrogenase [LDH] assays in vascular smooth muscle cells. The hot-water ($65^{\circ}C$) extract had a higher phenol content than the ethanolic extract. The hot-water extract showed a statistically significant increase in free radical scavenging activity and a greater ability to reduce proliferation of vascular smooth muscle cells stimulated with platelet-derived growth factor-BB. Taken together, hot-water extracts of S. fulvellum may be an important source of antioxidative and antiproliferative agents.