• International Journal of Oral Biology
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• v.41 no.4
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• pp.225-230
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• 2016

Inflammation from chronic and acute infections of distal organs and tissues such as periodontitis is a risk factor for atherosclerotic vascular processes. Recently, a new model of atherosclerosis with vascular pathologies was developed in the Mongolian gerbil. In this study, we attempted to develop a model of ligature-induced periodontitis in gerbils and compared the characteristics of that periodontitis model with that in rats and mice. Each gerbil, rat, and mouse was randomly assigned to groups of control and periodontitis. A thread was placed around the cervix of the right and left first molars in the mandible with knots placed on the mesial side of each molar. At day 14 after the ligation, the animals were sacrificed and their mandibles were dissected. To measure alveolar bone loss along with inflammation, histopathological and micro-CT analyses were carried out. Gerbils showed tooth characteristics of deeper gingival crevice, longer cusp, longer root trunk and shorter root than those of rats and mice. The increased CEJ-ABC distance in distal and PDL area in furcation was also observed in ligated gerbils. An inflammatory response in the connective tissue under the junctional epithelium was also shown in all the animals. As a result, we confirmed the induction of periodontitis by ligature in the gerbils. We therefore consider the gerbil to be a useful model for investigating relationship between periodontitis and vascular disease in the same animal.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.13-18
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• 2003

Reduced activation ferritic steel, JLF-1 steel (Fe-9Cr-2W-V-Ta), is one of the promising candidate materials for fusion reactor applications. Fracture toughness ($J_IC$) and tensile tests were carried out at room temperature and elevated temperature ($400^{\circ}C$). Two types of CT specimen were prepared to examine the effect of rolling direction on the fracture toughness of JLF-1 steel. Four types of tensile specimen were also prepared to investigate the property by the rolling direction and welding. The Micro Vickers hardness was measured at various distances of a cross section of the TIG joints of JLF-1 steel according to the heating history of each position. Finally, the fracture surface was observed by scanning electron microscopy (SEM).

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.1 s.256
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• pp.70-76
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• 2007

Elastic-plastic fracture mechanics is popularly used for integrity evaluation of major components, however, it is not easy to extract standard specimens from operating facility. This paper examines how ductile fracture toughness is characterized by a small punch testing technique in conjunction with finite element analyses incorporating a damage model. At first, micro-mechanical parameters constituting Rousselier model are calibrated for typical nuclear materials using both estimated and experimental load-displacement (P-$\delta$) curves of miniaturized specimens. Then, fracture resistance (J-R) curves of relatively larger standard CT specimens are predicted by finite element analyses employing the calibrated parameters and compared with corresponding experimental ones. It was proven that estimated results by the proposed method using small punch specimen is promising and might be used as a useful tool for ductile crack growth evaluation.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.4 s.181
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• pp.116-123
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• 2006

During the last two decades, many researchers investigated influences of stress triaxiality on ductile fracture for various specimens and structures. With respect to a transferability issue, the local approach reflecting micro-mechanical specifics is one of effective methods to predict constraint effects. In this paper, the applicability of the local approach was examined through a series of finite element analyses incorporating modified GTN (Gurson-Tvergaard-Needleman) and Rousselier models as well as fracture toughness tests. To achieve this goal, fracture resistance (J-R) curves of several types of compact tension (CT) specimens with various crack length, with various thickness and with/without 20% side- grooves were estimated. Then. the constraint effects were examined by comparing the numerically estimated J-R curves with experimentally determined ones. The assessment results showed that the damage models might be used as useful tool for fracture toughness estimation and both the crack length and thickness effects should be considered for realistic structural integrity evaluation.

• Korean Journal of Veterinary Research
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• v.50 no.3
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• pp.171-177
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• 2010

The purpose of this study was to evaluate the osteogenic capacity of water extract of danshen (Salvia miltiorrhiza Bunge). We have established in rat critical-sized calvarial defect model using the combination with collagen scaffold and danshen hydrophilic extract. All rats were extinguished at 8 weeks after bone graft surgery, and the bone regeneration ability of bone grafting sides was evaluated by plain radiography and micro-CT. These results revealed water extract of danshen had the potential to promote osteogenesis especially continuous oral administration with local treatment compared to one-shot local treatment. This compound may provide a new alternative agent for growth factors to promote bone healing and bone regeneration. In conclusion, these results suggest that danshen hydrophilic extract have the potential to promote osteogenesis in bone defects. Further studies about fusion technology with salvianolic acid B, peptides, growth factors, and scaffolds using of the combination of tissue engineering, cell engineering and mechanical engineering are needed.

• Korean Journal of Pharmacognosy
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• v.51 no.2
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• pp.122-130
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• 2020

To investigate the anti-inflammatory effect on Degenerative Osteoarthritis, Male sprague-Dawley rats were randomized and classified into three different concentration groups. We measured weekly weight change, dietary intake, drinking water intake, blood analysis like TNF-α (tumor necrosis factor-α), IL-6 (interleukin 6), TIMP-1 (tissue inhibitor of metalloprotease-1), MMP-2 (matrix metalloprotease-2), MMP-9 (matrix metalloprotease-9) and micro CT analysis. The results suggest that the treatment with herbal complex HP-04 improved the Monosodium iodoacetate (MIA) induced degenerative osteoarthritis and it could be applicable for the improvement of arthritic symptoms as a new therapeutic agent.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.6
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• pp.316-323
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• 2004

This paper develops an ADWHM(Advanced Digital Watt-Hour Meter) which integrates and implements the voltage management data record function and the load management data record function in the electronic watt-hour meter. ADWHM is developed based on PIC16F874 which is 8bit micro-controller of RISK type for the easy of programing and maintenance, and electronic power signal processing module is located at front of it to reduce the computing load of processor. Also, a 16kbyte EEPROM is used to record the voltage management data and load management data for a week as well as watt-hour data and USART communication mode is used to transfer data from ADWHM to PC. The accuracy of the voltage and unt measuring for ADWHM is verified by identifying the LCD display values of the ADWHM after the voltage signals of id levels from digital function generator is applied to PT(Potential Transformer) and CT(Current Transformer) output under state which it is separated from real power line. On the its basic functions such as watt-hour data recording function, voltage management data recording function and load management data recording function was verified by showing data for three days among the collected data to PC by RS232C communication from ADWHM which was connected to real power lines for a week.

• The Journal of Internal Korean Medicine
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• v.40 no.1
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• pp.58-69
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• 2019

Objective: This study investigated the effects of Hansu-Daebowon (HDW) on bone resorption in vitro and bone loss in vivo. Methods: Osteoclast differentiation was measured by counting TRAP (+) MNC formed from RAW 264.7 in the presence of RANKL. Bone pit formation was determined in an artificial bone slice loaded with RANKL-stimulated osteoclasts. To elucidate the mechanisms of the inhibitory effects of HDW on bone resorption and osteoclast differentiation, osteoclastogenic genes (i.e. TRAP, MMP-9, NFATc1, c-Fos, and Cathepsin K) were measured using real time PCR. Furthermore, bone loss was observed using micro-CT in an LPS-treated mammal model. Results: HDW inhibited the bone pit formation in vitro and inhibited bone loss in vivo. Moreover, HDW decreased the number of TRAP (+) MNCs in the presence of RANKL, and HDW inhibited the expressions of cathepsin K, MMP-9, TRAP, NFATc1, and c-Fos in the osteoclasts. Conclusion: HDW exerts inhibitory effects on bone loss and bone resorption resulting from the inhibitions of osteoclast differentiation and osteoclastogenic gene expression.

• Journal of Biomedical Engineering Research
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• v.38 no.4
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• pp.175-182
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• 2017

Microcurrent electrical stimulation(MES) has been used to accelerate recovery of atrophied skeletal muscle. However, convincing stimulation parameters for suppressing muscle atrophy due to injured sciatic nerve remains unclear. The objective of this study was to investigate the effective intensity of MES on restraining muscle atrophy with rat model underwent sciatic nerve injury(SNI). Twenty-5-week-old Sprague Dawley male rats were equally assigned to five groups : Control group(Control, CON, n = 4), Denervation group(Denervation, D, n = 4), Denervation with MES of $22{\mu}A$ group(Denervation + $22{\mu}A$, D+22, n = 4), Denervation with MES of $100{\mu}A$ group (Denervation + $100{\mu}A$, D+100 n = 4), Denervation with MES of $400{\mu}A$ group(Denervation + $400{\mu}A$, D+400, n = 4). To induce muscle atrophy, all rats in the D, D+22, D+100, and D+400 groups, were subjected to sciatic nerve injury on their right hindlimb and allowed to have 1 week of resting period. Following this period, rats underwent daily MES(60 min/ a day, 5times/1week) for 4 weeks. After that, we investigate morphological changes in muscle volume by using in vivo micro-computed tomography at week 0, 1, 3 and 5. After 5 weeks, the muscle volume had the highest value in D+400 group, and also noticeably increased in D+100 group compared to it in D group. The results of this study imply that MES with current intensities between $100-400{\mu}A$ can suppress muscle atrophy effectively.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.1
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• pp.22-29
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• 2007

Purpose: Metastatic thyroid cancers with I-131 uptake have been known to show no increase of FDG uptake whereas those without I-131 uptake tend to demonstrate increased uptake on PET. In this study, we evaluated the degree of FDG uptake in primary thyroid cancers of papillary histology before surgery. Material & Methods: Forty FDG PET studies were performed on the patients who had papillary cancer proven by fine needle aspiration. The degree of FDG uptake was visually categorized as positive or negative (positive if the tumor showed discernible FDG; negative if the tumor didn't) and the peak standard uptake value (peak SUV) of the papillary thyroid cancer (PTC) were compared with the size of PTC. Results: The mean size of 26 PTC with positive FDG uptake was $1.9{\pm}1.4\;cm(0.5{\sim}5\;cm)$. In 13 PTC with negative FDG uptake, the mean size of those was $0.5{\pm}0.2\;cm\;(0.2{\sim}0.9\;cm)$. All PTC larger than 1cm ($2.5{\pm}1.4\;cm,\;1{\sim}5\;cm$) have positive FDG uptake (peak $SUV=6.4{\pm}5.7,\;1.7{\sim}22.7$). Among the micropapillary thyroid cancer (microPTC; PTC smaller than 1cm), 8 microPTC show positive FDG uptake(peak $SUV=2.9{\pm}1.3,\;1.7{\sim}5.5$), while 13 microPTC show negative finding(peak $SUV=1.3{\pm}0.2,\;1.1{\sim}1.7$). The size of microPTC with positive FDG uptake is significantly larger than that of microPTC with negative FDG uptake ($0.7{\pm}0.1\;cm$ vs $0.4{\pm}0.2\;cm$, p=0.01). Conclusion: All PTCs larger than 1cm show positive FDG uptake in our study. In other words, thyroid lesions larger than 1cm with negative FDG uptake are unlikely to be PTC. So far, only poorly differentiated thyroid cancers are known to show increased FDG uptake. Our results seem to be contradictory to what is known in the literature. Further study is needed to understand better the significance of increased FDG uptake in PTC in relation to expression of NIS and GLUT.