• Journal of Korean Society of Steel Construction
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• v.15 no.3
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• pp.231-239
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• 2003

Many box girder bridges have been constructed during the past several decades due to their large bending and torsional rigidities as well as aesthetic considerations. However, box girders have shortcoming in that the cross section distorts under an eccentric loading and warps out of the section plane. Therefore, in order to reduce distortional stresses such as distortional warping and transverse bending normal stresses, diaphragms were generally installed in the box girders. Shapes of the diaphragms in steel-box-girder bridges constructed up to date were solid-plate, frame, and truss types. The objectives of this study using parametric study were to evaluate the appropriate stiffness ratio of intermediate diaphragms and then to propose the effective spacing and numbers of intermediate diaphragms based on the evaluated stiffness ratio. Target bridges for this study were straight continuous span bridges with a single-cell steel box section. The parameters for the parametric study were the shape of box section, the span numbers, the equivalent span length, the stiffness of intermediate diaphragms, and the spacing of intermediate diaphragms. From the results of the parametric study, the effective spacing and numbers as well as the stiffness ratio of the intermediate diaphragms will be presented.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.5
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• pp.497-503
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• 2014

Minimally invasive intramedullary nail insertion or plate osteosynthesis has shown good results for the treatment of long bone fractures. However, directly seeing the fracture site is impossible; surgeons can only confirm bone fragments through a fluoroscopic imaging system. The narrow field of view of the equipment causes malalignment of the fracture reduction, and radiation exposure to medical staff is inevitable. This paper suggests two methods to solve these problems: surgical navigation using 3D models reconstructed from computed tomography (CT) images to show the real positions of bone fragments and estimating the rotational angle of proximal bone fragments from 2D fluoroscopic images. The suggested methods were implemented using open-source code or software and evaluated using a model bone. The registration error was about 2 mm with surgical navigation, and the rotation estimation software could discern differences of $2.5^{\circ}$ within a range of $15^{\circ}$ through a comparison with the image of a normal bone.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.2
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• pp.138-149
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• 2000

Various modeling techniques for ultrasonic wave propagation and scattering problems in finite solid media are presented. Elastodynamic boundary value problems in inhomogeneous multi-layered plate-like structures are set up for modal analysis of guided wave propagation and numerically solved to obtain dispersion curves which show propagation characteristics of guided waves. As a powerful modeling tool to overcome such numerical difficulties in wave scattering problems as the geometrical complexity and mode conversion, the Boundary Element Method(BEM) is introduced and is combined with the normal mode expansion technique to develop the hybrid BEM, an efficient technique for modeling multi mode conversion of guided wave scattering problems. Time dependent wave forms are obtained through the inverse Fourier transformation of the numerical solutions in the frequency domain. 3D BEM program development is underway to model more practical ultrasonic wave signals. Some encouraging numerical results have recently been obtained in comparison with the analytical solutions for wave propagation in a bar subjected to time harmonic longitudinal excitation. It is expected that the presented modeling techniques for elastic wave propagation and scattering can be applied to establish quantitative nondestructive evaluation techniques in various ways.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.6
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• pp.983-988
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• 2010

The present study aims to investigate a possible mechanism of electroacupuncture (EA) in the spinal dorsal horn that may underlie N-methyl-D-aspartate (NMDA) receptor-associated extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) signaling pathways. The hot plate latency of the ipsilateral hindpaw of EA-treated rats was significantly decreased compared with complete Freund's adjuvant (CFA)-injected ones. The expressions of NR1 and NR2B subuint mRNA of NMDA receptor in the whole L4-5 segments are decreased by CFA treatment, but NR2B subunit was significantly recovered by EA treatment. When we detected the expression of ERK, there were no significant difference between normal and CFA-treated rats with EA or NMDA receptor antagonist MK801. But phosphorylated ERK expressions were markedly induced by CFA, but these inductions were significantly modulated by EA treatment. Although hosphorylation of ERK was also arrested by MK801, these inductions of CFA-injected rats was markedly inhibited only by co-treatment with EA and MK801. Phosphorylated cAMP response element-binding protein (CREB), ERK-related transcriptional factor, showed a significant increase in CFA-treated rats and this increase was slightly inhibited by EA and MK801 treatments. But immunoreaction for phosphorylated CREB were significantly increased by CFA treatment in the superficial laminae of the dorsal horn and these inductions were significantly arrested by co-treatment of EA and MK801. Consequently, the hyperalgesia induced by CFA are associated NMDA receptor and EA and MK801 may showed anti-hyperalgesia via same mechanism for inhibition of ERK and CREB phosphorylation in the dorsal horn.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.3
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• pp.284-294
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• 2006

Statement of problem. Proliferation of Candida albicans is primarily within the plaque on the fitting surface of the denture rather than on the inflamed mucosa. Consequently, the treatment of the denture is equally important as treatment of the tissue. Cleansing and disinfection should be efficiently carried-out as the organisms can penetrate into the voids of the acrylic resin and grow in them, from which they can continue to infect and reinfect bearing tissues. Purpose. The purpose of this study was to evaluate the applicability of photocatalytic reaction to eliminate Candida albicans from acrylic resin denture base, and to investigate the anti-fungal effect with various UVA illumination time. Materials and Methods. The specimens were cured by the conventional method following the manufacturer's instruction using thermal polymerized denture base resin (Vertex RS: Dentimex, Netherlands). $TiO_2$ photocatalyst sol(LT), which is able to be coated at normal temperature, was made from the Ti-alkoxide progenitor. The XRD patterns, TEM images and nitrogen absorption ability of the $TiO_2$ photocatalyst sol(LT) were compared with the commercial $TiO_2$ photocatalyst P-25. The experimental specimens were coated with the mixture of the $TiO_2$ photocatalyst sol(LT) and binder material (silane) using dip-coater, and uncoated resin plates were used as the control group. Crystallinity of $TiO_2$ of the specimen was tested by the XRD. Size, shape and chemical compositions were also analyzed using the FE-SEM/ EDS. The angle and methylene blue degradation efsciency were measured for evaluating the photocatalytic activity of the $TiO_2$ film. Finally, the antifungal activity of the specimen was tested. Candida albicans KCTC 7629(1 ml, initial concentration $10^5$ cells/ ml) were applied to the experiment and control group specimens and subsequently two UVA light source with 10W, 353 nm peak emission were illuminated to the specimens from 15cm above. The extracted $2{\mu}l$ of sample was plated on nutrient agar plate ($Bacto^{TM}$ Brain Heart Infusion; BD, USA) with 10 minute intervals for 120 minute, respectively. It was incubated for 24 hours at $37^{\circ}C$ and the colony forming units (CFUs) were then counted. Results. Compared the characteristics of LT photocatalyst with commercial P-25 photocatalyst, LT were shown higher activity than P-25. The LT coated experimental specimen surface had anatase crystal form, less than 20 nm of particle size and wide specific surface area. To evaluate the photocatalytic activity of specimens, methylene blue degradation reaction were used and about 5% of degradation rate were measured after 2 hours. The average contact angle was less than $20^{\circ}$ indicating that the LT photocatalyst had hydrophilicity. In the antifungal activity test for Candida albicans, 0% survival rate were measured within 30 minute after irradiation of UVA light. Conclusion. From the results reported above, it is concluded that the UVA-LT photocatalytic reaction have an antifungal effect on the denture surface Candida albicans, and so that could be applicable to the clinical use as a cleaning method.

• The Journal of the Petrological Society of Korea
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• v.25 no.1
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• pp.85-88
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• 2016

The new rocks of the oceanic crust, like basalt, are created in the mid-oceanic ridge, and the magnetic polarities of the rocks are supposed to be oriented as following the Earth's magnetic field. An extensive magnetic survey of total field at sea level reveals mainly unusual north-south magnetic stripes parallel to the axis of the mid-oceanic ridge, especially in the Atlantic Ocean. From this stripes the Earth's magnetic field is considered as repeatedly 'flipped'(the N pole becoming the S pole, and vice versa) and many times over geological time. The discovery of stripes of alternately normal and reversed-magnetized rocks forming the ocean floor has been a key evidence for the sea-floor spreading, continental drift, and plate tectonics. This study introduces a simple apparatus to explain a possible mechanism of the magnetic reversal in the new oceanic crust, which makes a magnetic stripe adjacent to the mid-oceanic ridge. The apparatus shows a bar magnet effect of adjoined stripes to have a special magnetic polarity on the rocks in the center of the mid-oceanic ridge. The new magnetic stripe seems to be generated not only by Earth's magnetic field, but also by neighbored stripes in the mid-oceanic ridge, acting as a bar magnet.

• Journal of Veterinary Clinics
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• v.29 no.5
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• pp.412-415
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• 2012

A 1-year-old, castrated male Yorkshire terrier (case 1) and a 7-year-old female Poodle (case 2) presented with delayed union fractures. In case 1, the dog had a fractured right distal radius and ulna. In case 2, the dog had a fractured left distal tibia and fibula. A physical examination and radiographs performed in both dogs revealed delayed union fractures with large gaps. The fracture sites were fixed by bone plate and screws. Autogenous cancellous bone graft was applied into the fracture gap. To encourage rapid bone union, we used matrigel containing $20{\mu}g$ of recombinant human bone morphogenetic protein-2 (rhBMP-2) in the fracture site. Radiographs were taken postoperatively to monitor healing. Rapid bone union was noted in both dogs in long-term radiographs. In case 1, the radiographs revealed that the fracture gaps of the radius and ulna were bridged at 2 weeks. Fracture lines were not observed and normal appearance was restored at 20 weeks. In case 2, the radiographs showed that fracture repair had progressed at 11 weeks. The fractures healed faster than expected in these two cases. The results indicate that rhBMP-2 and matrigel may be effective and useful materials to enhance healing of delayed fractures.

• Food Science of Animal Resources
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• v.22 no.3
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• pp.247-251
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• 2002

This study was carried out to investigate the keeping quality of market milks collected from several dairy processing companies. Microbiological, chemical, and sensory properties of Intra-high temperature(UHT) treated milks stored at 5, 10, 15t were evaluated during the storage of 154days. No significant difference during the storage was shown in bacterial counts, pH and titratable acidity. Standard plate count(SPC) was remained less than 20,000 cfu/ml after 15 day storage at 5, 10, 15$^{\circ}C$. Also, Psychrotrophic bacterial count and Coliform count were not detected or detected at low level. The pH ranged from 6.55 to 6.83 and the titratable acidity ranged from 0.13% to 0.16%. In sensory evaluation, UHT milks showed normal flavor until 10days, but thereafter off-flavor was slightly developed. Consequently, UHT milks remained in good quality when stored at 5$^{\circ}C$,10$^{\circ}C$t until 15days except sensory properties. According to this experiment, the shelf-life of UHT milk can be extended to 10 days, even though maintaining the storage temperature strictly below 10 t in milk market is not easy.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.1
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• pp.135-143
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• 1996

The aim of this study was to evaluate bone promotion of bioreabsorbable guided tissue regeneration for generating new bone adjacent to osseointegrated implants in dogs. Third premolars were extracted in dgo mandibles. Cylindrical HA-coated implants were placed into extracted sockets in dogs. And test sites were protected by $GUIDOR^{(R)}$ matrix barrier. But control sites were not protected by membrances. The sites were examined clinically, radiologically, and histologically after 1, 2, and 4 months to assess bone regeneration. The results obtained were as foolows : 1. There were the good healing and the stability of $GUIDOR^{(R)}$ matrix barrier in experimental site during the healing period. 2. Complete resorption of $GUIDOR^{(R)}$ matrix barrier was clinically observed about 4 months postoperatively. 3. The woven bone changed to mature bone with a normal cortical plate and mature, resting periosteum after 4 months. 4. In experimental site, there was a significantly greater bone promtion than observed in control site. 5. $GUIDOR^{(R)}$ matrix barrier was useful for the preparation of immediate dental implants.

• Korean Journal of Cleft Lip And Palate
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• v.4 no.2
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• pp.51-68
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• 2001

Midfacial hypoplasia in patients with clefts of the lip and palate is considered to be the result of congenital dysmorphogenesis. And cleft lip and palate developes facial deformity, jaw abnormality, speech problem, which is most frequent hereditary deformity in maxillofacial region. So cleft lip and palate is characterized by midface deformity which shaws maxillary anterior nasal septal deviation and deformity. Our study describes congenital correlates of midfacial hypoplasia by examining the displacement of a normal complement of parts, a triangular tissue deficiency low on the lip border on the columellar side, and a linear deficiency and displacement in the line of the bilateral cleft lip. 15 patients with bilateral cleft lip and palate were taken impression before operation, but the patient who had other abnormalities and complications were excluded. Average age is 3.4 months and they were classified into both complete, both incomplete and complete & incomplete group. The obtained results were as follows 1. There were no differences on intercanthal width and canthal width between each of the groups. 2. Both complete group had longer lateral ala length than both incomplete group, but there were no differences between both complete group and complete side of com. & incom. group and both incomplete group and incomplete side of com. & incom. group. 3. Columella length was greater in both incomplete group than in both complete group, but there was no difference between both complete group and complete side of com. & incom. group and both incomplete group and incomplete side of com. & incom. group. 4. Both complete group had longer ala width & ala base width than both incomplete group had. But there were no differences between both complete group and complete side of com. & incom. group and both incomplete group and incomplete side of com. & incom. group. 5. There were no differences between each of the groups on upper lip length, but nose/mouth width ratio was greater in both complete group than in both incomplete group. 6. Pronasale(pm), subnasle(sn), la~rale superioris(ls), stomion(sto) points were located around the central vertical line of face but deviated to incomplete side in com. & incom. group. 7. Nasal tip protrusion was greater in both incomplete group and com. & incom. group than both complete group, but there was no difference between both incomplete group and com. & incom. group.