• Journal of Environmental Science International
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• v.17 no.4
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• pp.439-449
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• 2008

Algicidal bacterium was isolated from sea water during the declining period of Cochlodinium polykrikoides blooms and this bacterium had a significant algicidal activity against C. polykrikoides. In this study, algicidal bacterium was identified on the basis of biochemical and chemotaxonomic characteristics, and analysis of 16S rDNA sequences. The algicidal bacterium showed 98.6% homology with Micrococcus luteus ATCC $381^T$. Therefore, this bacterium was designated Micrococcus luteus SY-13. The optimal culture conditions of the algicidal bacterium was $25^{\circ}C$, initial pH 8.0, and 3.0% NaCl concentration. M. luteus SY-13 is assumed to produce secondary metabolites which have algicidal activity. When 10% culture filtrate of this strain was applied to C. polykrikoides ($1.0\;{\times}\;10^4\;cells/ml$) cultures, over 98% of C, polykrikoides cells were destroyed within 6 hours. The culture filtrate of M. luteus SY-13 exhibited similar algicidal activity after heat-treatment at $121^{\circ}C$ for 15 min. While algicidal activity remained in filtrates with pH adjusted to 8.0, loss of algicidal activity occurred when the pHs of filtrates were adjusted to over 9.0 or heat-treated at $121{\times}180^{\circ}C$ for 1 hour. M. luteus SY-13 showed significant algicidal activities against C. polykrikoides (98.9%) and a wide algicidal range against various harmful algal bloom (HAB) species. However, there was no algicidal effect on diatom and marine livefood organisms except Isocrysis galbana. These results suggest that M. luteus SY-13 could be a candidate for use in the control of HABs.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.6
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• pp.727-735
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• 2005

Statement of problem. Platform switching in implant prosthesis has been used for esthetic and biological purpose. But there are few reports for this concept. Purpose. The purpose of this study is evaluation of platform switching in wide implant by three dimensional finite element analysis. Materials and Methods. The single implant and prosthesis was modeled in accordance with the geometric designs for Osstem implant system. Three-dimensional finite element models were developed for (1) a wide diameter 3i type titanium implant 5 mm in diameter, 13 mm in length with wide cemented abutment, titanium alloy abutment screw, and prosthesis (2) a wide diameter 3i type titanium implant 5 mm in diameter, 13 mm in length with regular cemented abutment, titanium alloy abutment screw and prosthesis(platform switching) was made for finite element analysis. The abutment screws were subjected to a tightening torque of 30 Ncm. The amount of preload was hypothesized to 650N, and round and flat type prostheses were loaded to 200 N. Four loading offset point (0, 2, 4, 6 mm from the center of the implants) were evaluated. Models were processed by the software programs HyperMesh and ANSA. The PAM-CRASH 2G simulation software was used for analysis of stress. The PAM-VIEW and HyperView were used for post processing. Results. The results from experiment were as follows; 1. von Mises stress value is increased in order of bone, abutment, implant and abutment screw. 2. von Mises stress of abutment screw is lower when platform switching. 3. von Mises stress of implant is lower when platform switching until loading offset 4 mm. 4. von Mises stress of abutment is similar between each other. 5. von Mises stress of bone is slightly higher when platform switching. Conclusion. The von Mises stress pattern of implant components is favor when platform switch ing but slightly higher in bone stress distribution than use of wide abutment. The research about stress distribution is essential for investigation of the cortical bone loss.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.2
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• pp.310-317
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• 2009

Dens evaginatus is a dental anomaly involving an extra cusp or tubercle that protrudes from the occlusal surface of the affected tooth. The prevalence of dens evaginatus is 1 to 4 percent, and dens evaginatus is observed most commonly in premolars. It can be worn or fractured easily, resulting in pulpal exposure, pulpal infection, loss of vitality, facial infection and osteomyelitis. Since the tooth frequently has the immature apex when the tubercle is fractured, there is difficulty in treatment. Although calcium hydroxide is widely used for pulp treatment of an immature permanent tooth, several alternatives have been suggested to reduce patient's appointments. Mineral trioxide aggregate is considered biocom-patible and has excellent marginal sealing ability. In addition, it can minimize patient's visits. In this case report, apexification with MTA was attempted on the immature premolars in patients with cellulitis patient, caused by pulp necrosis due to dens evaginatus. Favorable clinical and radiologic results were achieved. In one case, continued root formation was observed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.8
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• pp.737-743
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• 2004

A fixed-tuned SIS(Superconductor-Insulator-Superconductor) mixer across 120∼180 GHz band has been developed. This mixer employs an SIS chip fabricated by Nobeyama radio observatory which consists of a series array of 6 Nb/Al-Al$_2$O$_3$/Nb junctions in a microstrip line on a fused quartz substrate. The SIS chip is placed at the center of the half-height waveguide mixer mount to have a good incoming signal coupling over the whole frequency band. No mechanical tuner was used in the SIS mixer and the RF signal and local oscillator power are injected to the mixer via a cooled cross-guide coupler. In order to prevent the IF signal loss, the If output impedance of the SIS mixer was matched to the 50 $\Omega$ input impedance of the IF chain. Measured double sideband noise temperatures of a receiver using the SIS mixer are 32∼131 K over 120∼180 GHz band. The developed SIS mixer is now in use for radio astronomical observations on the TRAO 14 m radio telescope.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.4
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• pp.436-441
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• 2008

In this paper, we derived the Y-parameter of the recently reported Balun-BPF with a dual mode ring resonator by using the network analysis method. Using the derived Y-parameter we verified that the Balun-BPF structure satisfy the balun conditions. In order to design the Balun-BPF with arbitrary characteristics using the standard BPF design method with ease we derived the immittance slope parameters of the dual mode ring resonator with a load. The notch frequencies are also predicted. By designing with the proposed equations, simulating with a circuit simulator, fabricated and measured a Balun-BPF we confirmed the validation of the equations. The measured data shows bandwidth of 71 MHz and insertion loss of 0.92 dB at the center frequency of 2.46 GHz. It shows the phase imbalance of $174{\sim}181$ degree and the magnitude imbalance within 0.5 dB.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.2
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• pp.166-170
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• 2015

Foot-and-mouth disease (FMD) is a highly contagious disease affecting cloven-hoofed animals and causes severe economic loss and devastating effect on international trade of animal or animal products. Since FMD outbreaks have recently occurred in some Asian countries, it is important to understand the relationship between diverse immunogenomic structures of host animals and the immunity to foot-and-mouth disease virus (FMDV). We performed genome wide association study based on high-density bovine single nucleotide polymorphism (SNP) chip for identifying FMD resistant loci in Holstein cattle. Among 624532 SNP after quality control, we found that 11 SNPs on 3 chromosomes (chr17, 22, and 15) were significantly associated with the trait at the p.adjust <0.05 after PERMORY test. Most significantly associated SNPs were located on chromosome 17, around the genes Myosin XVIIIB and Seizure related 6 homolog (mouse)-like, which were associated with lung cancer. Based on the known function of the genes nearby the significant SNPs, the FMD resistant animals might have ability to improve their innate immune response to FMDV infection.

• Korean Journal of Community Nutrition
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• v.10 no.1
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• pp.70-78
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• 2005

Zinc is known to have important effects on insulin activity and to increase the body fat deposition. The purpose of this study was to investigate the zinc status and obesity in 50 type 2 diabetic women visiting public health center and hospital. The mean age was 57.9 $\pm$ 6.9 years old. The mean of diabetic duration was 8.0 $\pm$ 6.5 years. Body mass index (BMI) of diabetes was $23.2 \pm 2.3 kg/m^2$. There were no significant differences of mean age, anthropometric indices, and insulin level other than fasting blood sugar (p < 0.001) and insulin resistance (p < 0.00l) between diabetes and control group. The obesity ratio of diabetes was $20\%$, $66\%$ and $84\%$ for BMI, waist circumference and waist/hip ratio (WHR), respectively. Plasma zinc level was not significantly different between diabetes and control group. However, urinary zinc excretion of diabetes was approximately twice of control group (p < 0.001). Urinary zinc loss was fivefold higher in the hyperglycemia ($HbA_{lc}> 10\%$) than in normal blood glucose (p < 0.001). Anthropometric indices were decreased in hyperglycemia. On the other hand, there were the tendency of increased urinary zinc in obese group for waist circumference and percent of body fat. These results suggested that controlled normal blood glucose could improve hyperzincuria and anthropometric changes in type 2 women diabeties.

• Journal of Energy Engineering
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• v.11 no.1
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• pp.26-33
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• 2002

In this paper, incompressible and compressible flow characteristics around the butterfly valve have been investigated. In order to simplify the problem, a flat disk valve with various valve disk angles and pressure ratios is considered in the present calculations. It was found that as the disk angle increases, the stagnation point on the front surface of the disk moves to the center of the surface and the inflow velocity decreases. The maximum flow velocity occurs at the downstream of throat because of the formation of vents contracta. As the pressure ratio decreases, compressibility effects increase and the jet formed between the throttle body wall and the disk edge becomes supersonic. This flow also builds up as a shock cell structure. The increase of disk angle and pressure ratio makes the mass flow at the inlet decrease, while the increase of disk angle and the decrease of pressure ratio make the pressure loss coefficient increase.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.2 no.2
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• pp.43-52
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• 1999

This study was carried out to verify results of the nursery seedbeds. From November of 1997 to September of 1998, the artificial banking slopes in the greenhouse of the College of Agriculture and Life Sciences, Seoul National University were seeded with the mixtures of those species. Most of exotic species showed relatively poor development of root as short as 30cm. Also the green weight of root biomass of the native species was more than two times than that of the exotic species. On the other hand, it was found that the exotic species have relatively well-developed fine roots. Thus, it was concluded that the seed-mixture of the native species with long and thick roots and the exotic species with fine roots be the most effective method for topsoil erosion control on banking-slopes. The artificial rainfall system treatment(30mm/hr, 60mm/hr, 100mm/hr) on $30^{\circ}$ banking-slopes did not cause any significant change in the amount of soil loss by erosion. The root system was best developed in the plot of 1,000 seedlings per square meter and it performed well for soil erosion control. Consequently, in the case of seeding of single herbaceous species without mixing any woody seeds, the expected seedlings were 1,000 to 2,000 per square meter.

• Applied Chemistry for Engineering
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• v.2 no.4
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• pp.399-410
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• 1991

New separation process was developed for the preparation of storage-stable liquid dyes. The extent of aggregation of dye molecules was measured with respect to storage time of liquid dyes under different salt environments. Hollow-fiber membranes were modified by immobilization of inorganic crystals onto the surface of membrane. Using surface-treated membranes, counter diffusion technology was introduced to selectively remove salts from dye solution. The separation factors were 10-700, and the loss of dye molecules was less than 0.4 %. Membrane permeabilities for sodium ions($U_{M,Na}$) and dye molecules($U_{M,Dye}$) were found to be 2.75 and $0.72l/m^2/hr$, respectively, in the case of surface-treated membranes. The effects of various operating parameters on desalting efficiency were also investigated.