• Transactions of the KSME C: Technology and Education
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• v.1 no.2
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• pp.153-165
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• 2013

The established gait analysis studies have regarded leg as one single spring. If we can design a knee-ankle actuating mechanism as a primary actuator for supporting knee extension, it might be possible to revolutionary store or release elastic strain energy, which is consumed during the gait cycle, and as a result leg stiffness is expected to increase. An ankle joint actuating mechanism that stores and releases the energy in ankle joint is expected to support and solve excessive artificial leg stiffness caused by the knee actuator (primary actuator) to a reasonable extent. If unnecessary kinematic energy is released with the artificial speed reduction control designed to prevent increase in gait speed caused by increase in time passed, it naturally brings question to the effectiveness of the actuator. As opposed to the already established studies, the authors are currently developing knee-ankle two actuator system under the concept of increasing lower limb stiffness by controlling the speed of gait in relative angular velocity of the two segments. Therefore, the author is convinced that compensatory mechanism caused by knee actuating must exist only in ankle joint. Ankle joint compensatory mechanism can be solved by reverse-examining the change in metatarso-phalangeal joint (MTPJ) tilt angle (${\theta}_1=0^{\circ}$, ${\theta}_2=17^{\circ}$, ${\theta}_3=30^{\circ}$) and the effect of change in gait speed on knee activity.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.3
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• pp.432-438
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• 2017

Objective: The objective of this study was to evaluate the effect of combinations of $NaNO_2$ and NaCl concentrations on Listeria monocytogenes (L. monocytogenes) growth in emulsion-type sausage. Methods: Emulsion-type sausages formulated with different combinations of $NaNO_2$ (0 and 10 ppm) and NaCl (1.00%, 1.25%, and 1.50%) were inoculated with a five-strain L. monocytogenes mixture, and stored at $4^{\circ}C$, $10^{\circ}C$, and $15^{\circ}C$, under aerobic or vacuum conditions. L. monocytogenes cell counts were measured at appropriate intervals, and kinetic parameters such as growth rate and lag phase duration (LPD) were calculated using the modified Gompertz model. Results: Growth rates increased (0.004 to 0.079 Log colony-forming unit [CFU]/g/h) as storage temperature increased, but LPD decreased (445.11 to 8.35 h) as storage temperature and NaCl concentration increased. The effect of combinations of NaCl and low-$NaNO_2$ on L. monocytogenes growth was not observed at $4^{\circ}C$ and $10^{\circ}C$, but it was observed at $15^{\circ}C$, regardless of atmospheric conditions. Conclusion: These results indicate that low concentrations of $NaNO_2$ and NaCl in emulsion-type sausage may not be sufficient to prevent L. monocytogenes growth, regardless of whether they are vacuum-packaged and stored at low temperatures. Therefore, additional techniques are necessary for L. monocytogenes control in the product.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.24 no.2
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• pp.263-274
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• 1994

The purpose of this study was to investigate the remodeling process of the streptozotocin-induced diabetic rat's resected condyle. This experiment was performed with male Sprague-Dawly strain rats weighing approximately 250 gm, which were rendered diabetic by an intravenous injection of streptozotocin(70㎎/㎏ body weight). After condylectomy, experimental rats were serially terminated on the 1st week, the 2nd week, the 3rd week, and the 4th week. The following termination, the mandibles were dissected out to make specimens. Each mandibular condyle was radiographed with Hitex HA-80(Hitex Co., Ltd. Japan). In addition to radiographic observation, the mandibular condyles, further decalcified and embedded in paraffin, were sectioned and stained with Hematoxylin and Eosin, Toluidine blue and Masson's trichrome. They were observed with a light microscope and a polarizing microscope. The results were as follows. 1. Soft X-ray radiograms revealed proliferation of bone after 1 week in both groups. Irregularly repaired bones and dense trabeculae were clearly observed in experimental group. 2. The resected condyles were repaired by intramembraneous and endochondral bone formation in both groups. 3. Bone tissue repair was initiated from the adjacent margin of resected bone, and cartilaginous tissues were observed at the top of repaired bone in both groups. 4. The number of osteoblasts of experimental group was small, compared with control group. Each osteoblast was small and flat. The thin trabeculae were irregularly formed. 5. Collagens of bone were gradually matured in both groups, but the degree of maturation was lower in experimental group. 6. Fibrous tissues covered the upper parts of repaired bone were densely arranged in the both groups. Conclusively, atrophied osteoblasts, immature collagen of bone, and thin and irregular trabeculae which were characterized in the diabetes experimental group showed diabetes disturbed osteoblastic function and caused disturbance of remodeling process of bone.

• Biomedical Science Letters
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• v.9 no.3
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• pp.145-150
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• 2003

In the intestinal mucosa, mast cells are thought to be responsible for the expulsion of parasites. We investigated the relationship of worm expulsion and mast cells in C3H/HeN and BALB/c mice infected with Echinostoma hortense. In addition, we examined whether the worm recovery rate was associated with the strain of mice, and whether a toluidine stain and immunohistochemistry using the c-kit antibody was effective in the detection of mast cells. In order to investigate the mucosal immune response of C3H/HeN and BALB/c mice, each mouse was infected orally with 30 E. hortense metacercariae. Then, the number of mucosal mast cells and worm recovery rates was observed in experimentally infected mouse strains between 1 week and 8 weeks post infection (PI). Mucosal mast cells were increased in 3 weeks P.I. in C3H/HeN and BALB/c mice. On the other hand, only mucosal goblet cells and worm recovery rates correlated in C3H/HeN mice (P=0.0482). Worm recoveries in C3H/HeN mice were 65.7$\pm$5.6, 53.3$\pm$5.4 and 6.7$\pm$0.6 in week 1, 2, and 3 P.I. and strongly decreased in week 3 P.I. Worm recoveries in BALB/c mice were 23.0$\pm$2.5, 10.0$\pm$1.0, and 6.7$\pm$0.6% in week 1, 2, and 3 P.I. and gradually decreased from week 1 P.I. to week 3 P.I. Worm recoveries in C3H/HeN mice were significantly higher than in BALB/c mice (P<0.00l). The number of mast cells in C3H/HeN and BALB/c mice using the anti-c-kit antibody reached to a peak in week 3 P.I. and recovered as normal level in week 5 P.I. and 6 P.I. The number in E. hortense-infected C3H/HeN mice (P=0.0015) was higher than in E. hortense-infected BALB/c mice (P=0.01) compared with the control group. There were significant differences in the number of mast cells among regions of the intestine in in C3H/HeN mice (P<0.05) but not in BALB/c mice (P>0.05). Immunohistochemistry using the anti-c-kit antibody was significant method as an examination of the number of mast cells (P=0.0002). In conclusion, the present study demonstrated that mast cells play an important role in worm recovery, and immunohistochemistry using the anti-c-kit antibody was superior to toluidine stain as an examination of mast cells.

• Proceedings of the Microbiological Society of Korea Conference
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• 2007.05a
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• pp.120-122
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• 2007

All living organisms use numerous signal-transduction pathways to sense and respond to their environments and thereby survive and proliferate in a range of biological niches. Molecular dissection of these signalling networks has increased our understanding of these communication processes and provides a platform for therapeutic intervention when these pathways malfunction in disease states, including infection. Owing to the expanding availability of sequenced genomes, a wealth of genetic and molecular tools and the conservation of signalling networks, members of the fungal kingdom serve as excellent model systems for more complex, multicellular organisms. Here, we employed Cryptococcus neoformans as a model system to understand how fungal-signalling circuits operate at the molecular level to sense and respond to a plethora of environmental stresses, including osmoticshock, UV, high temperature, oxidative stress and toxic drugs/metabolites. The stress-activated p38/Hog1 MAPK pathway is structurally conserved in many organisms as diverse as yeast and mammals, but its regulation is uniquely specialized in a majority of clinical Cryptococcus neoformans serotype A and D strains to control differentiation and virulence factor regulation. C. neoformans Hog1 MAPK is controlled by Pbs2 MAPK kinase (MAPKK). The Pbs2-Hog1 MAPK cascade is controlled by the fungal "two-component" system that is composed of a response regulator, Ssk1, and multiple sensor kinases, including two-component.like (Tco) 1 and Tco2. Tco1 and Tco2 play shared and distinct roles in stress responses and drug sensitivity through the Hog1 MAPK system. Furthermore, each sensor kinase mediates unique cellular functions for virulence and morphological differentiation. We also identified and characterized the Ssk2 MAPKKK upstream of the MAPKK Pbs2 and the MAPK Hog1 in C. neoformans. The SSK2 gene was identified as a potential component responsible for differential Hog1 regulation between the serotype D sibling f1 strains B3501 and B3502 through comparative analysis of their meiotic map with the meiotic segregation of Hog1-dependent sensitivity to the fungicide fludioxonil. Ssk2 is the only polymorphic component in the Hog1 MAPK module, including two coding sequence changes between the SSK2 alleles in B3501 and B3502 strains. To further support this finding, the SSK2 allele exchange completely swapped Hog1-related phenotypes between B3501 and B3502 strains. In the serotype A strain H99, disruption of the SSK2 gene dramatically enhanced capsule biosynthesis and mating efficiency, similar to pbs2 and hog1 mutations. Furthermore, ssk2, pbs2, and hog1 mutants are all hypersensitive to a variety of stresses and completely resistant to fludioxonil. Taken together, these findings indicate that Ssk2 is the critical interface protein connecting the two-component system and the Pbs2-Hog1 pathway in C. neoformans.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.62-68
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• 2016

The feeder cable assembly is an automotive part used for telecommunication. If it malfunctions, the control and safety of the automobile can be put at risk. ALT (Accelerated Life Testing) is a testing process for products in which they are subjected to conditions (stress, strain, temperatures, etc.) in excess of their normal service parameters in an attempt to uncover faults and potential modes of failure in a short amount of time. Failure is caused by defects in the design, process, quality, or application of the part, and these defects are the underlying causes of failure or which initiate a process leading to failure. Thermal shock occurs when a thermal gradient causes different parts of an object to expand by different amounts. Thermal shock testing is performed to determine the ability of parts and components to withstand sudden changes in temperature. In this research, the main causes of failure of the feeder cable assembly were snapping, shorting and electro-pressure resistance failure. Using the Coffin-Manson model for ALT, the normal conditions were from Tmax = $80^{\circ}C$ to Tmin = $-40^{\circ}C$, the accelerated testing conditions were from Tmax = $120^{\circ}C$ to Tmin = $-60^{\circ}C$, the AF (Acceleration Factor) was 2.25 and the testing time was reduced from 1,000 cycles to 444 cycles. Using the Bxlife test, the number of samples was 5, the required life was B0.04%.10years, in the acceleration condition, 747 cycles were obtained. After the thermal shock test under different conditions, the feeder cable assembly was examined by a network analyzer and compared with the Weibull distribution modulus parameter. The results obtained showed good results in acceleration life test mode. For the same reliability rate, the testing time was decreased by a quarter using ALT.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.5
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• pp.464-470
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• 1985

Some eels Anguilla japonica, ranging from 16 to 23 g in their weight(average: 20 g), were sampled at the private eel farming company equipped with water recycling system, located at Kimhae city, Kyungnam Province, Korea. Three kinds of vaccine were prepared with Vibrio anguillarum (EPM-8406) isolated at National Fisheries University in Korea for the immune response experiment against eels; those vaccines were made by inactivating the strain with $0.3\%$ formalin for 24 hrs at $25^{\circ}C$, heating for 3 mins or for 15 mins at $121^{\circ}C$, respectively. The various optimal vaccination conditions for the control of vibriosis in the fish were investigated based on the cultivation temperature, vaccination concentration and booster effect. The maximum titer rapidly increased with higher temperature up to $23^{\circ}C$, but there were little differences between $23^{\circ}C\;and\;28^{\circ}C$. The formalin-killed vaccine showed good efficacy at the injection concentration of above $10^8$ cells per fish and little effect at the below $10^7$ cells. The booster effect on the vaccination showed good efficacy above twice-injections with little difference between the numbers of injection.

• Microbiology and Biotechnology Letters
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• v.34 no.3
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• pp.244-249
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• 2006

In order to select the best strains to have the feasibility of Cheonghju brewing, 10 wild type yeast strains from 300 different types of Nuruk were investigated on their ethanol resistance, resistance to glucose and flocculation. The amounts of alcohol, organic acids, and volatile compounds, Brix, pH were also examined for the alcoholic beverages made with the 10 selected strains. Almost all strains showed alcohol production activities in the medium containing 18%(v/v) ethanol and 29%(w/v) glucose. The strains 90-2 showed a higher flocculation activity than other strains. Strains 54-3, 90-2 and 91-5 produced more alcohol than control strain (7.42%(w/w)) when fermented with wild type yeast strains. In addition, alcoholic beverages containing low acetic acid also showed low levels of total acidity. GC/MS analysis of the product showed 4 alcohols, 11 esters and 1 acid as volatile compounds. Selected strains were tentatively identified as Phichia sydowiorum (91-5), Zygosaccharomyces cidri (192-2 and 271-4), and as Saccharomyces cerevisiae (18-2, 54-3, 90-2, 91-2, 98-2, 99-5 and 272-7) by BIIOLOG method.

• Journal of Korean Foot and Ankle Society
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• v.22 no.1
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• pp.38-43
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• 2018

Purpose: Treatment of diabetic foot infection due to methicillin-resistant Staphylococcus aureus (MRSA) remains challenging. Applying vancomycin-impregnated cement is one of the best methods of treatment. Vancomycin-impregnated cement has been used worldwide; however, to date, there is a limited number of studies regarding its use. We evaluated the duration of antimicrobial activity of vancomycin-impregnated cement stored at room temperature after manufacturing. Materials and Methods: The vancomycin-impregnated cement was manufactured by mixing 1 g of vancomycin with 40 g of polymer and adding 17.90 g of liquid monomer. The cement dough was shaped into flat cylinders with diameter and height of 6 mm and 2 mm, respectively. Another cement of the same shape without mixing vancomycin was prepared as the negative control. All manufactured cements were sterilized with ethylene oxide gas and stored at room temperature. Each cement was placed on Mueller Hinton agar plate lawned with standard MRSA strain. Standard vancomycin disk and gentamicin disk were placed together. After 24 hours, the diameter of inhibition zone was measured, and if the diameter was less than 15 mm, vancomycin-impregnated cement was regarded as a loss of antimicrobial activity. The study was repeated every 2 weeks until vancomycin-impregnated cements lost their antimicrobial activity. Results: Vancomycin-impregnated cement stored for a duration of 16 weeks created a 14 mm inhibition zone, while vancomycin disk created a 15 mm inhibition zone. Vancomycin-impregnated cement stored for a duration of 17 weeks created 7 mm and 9 mm inhibition zones, while vancomycin disk created 16 mm and 15 mm inhibition zones, respectively. Conclusion: We found a decrease of antimicrobial activity in vancomycin-impregnated cements after 16 weeks. After 17 weeks, they showed definite loss of antimicrobial activity. Therefore, we recommend not using vancomycin-impregnated cement spacers that has been stored for more than 16 weeks at room temperature.

• Research in Plant Disease
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• v.15 no.3
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• pp.222-229
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• 2009

A Pseudomonas strain SG3 producing biosurfactant and showing antifungal and insecticidal activities was isolated from agricultural soil severely contaminated with machine oils. The antagonistic bacterium inhibited mycelial growth of all of the tested fungal pathogens. The fermentation broth of SG3 also effectively suppressed the development of various plant diseases including rice blast, tomato gray mold, tomato late blight, wheat leaf rust, barley powdery mildew and red pepper anthracnose. An antifungal substance was isolated from the fermentation broth of SG3 by ethyl acetate partitioning, silica gel column chromatography and preparative HPLC under the guide of bioassay. The chemical structure of the antifungal substance was determined to be rhamnolipid B by mass and NMR spectral analyses. The antifungal biosurfactant showed a potent in vivo antifungal activity against gray mold and late blight on tomato plants. In addition, rhamnolipid B inhibited mycelial growth of B. cinerea causing tomato gray mold and zoospore germination and mycelial growth of P. infestans causing tomato late blight. Pseudomonas sp. SG3 producing rhamnolipid B could be used as a new biocontrol agent for the control of plant diseases occurring on tomato plants.