• Journal of Wetlands Research
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• v.21 no.4
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• pp.365-373
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• 2019

In this study, we investigated the effect of wave height in coastal areas using discrete wavelet transform in Taehwa river basin in Ulsan. Through the decomposition result of tide data using daubechies level 7 wavelet and Curve Fitting Function, we confirmed that detail components of d₃ and d₄ were semidiurnal and diurnal components and approximation component(a₆) was the long period of lunar fortnight constituent. The decomposed tide data in six level was divided into tide component with periodicity and wave component with non-periodicity using autocorrelation function and fourier transform. Finally, we confirmed that the tide component is consisted 66% and wave component is consisted 34%. So, we quantitatively assessed the effect of wave on coastal areas. The result could be used for coastal flood risk management considering the effect of wave.

• Journal of radiological science and technology
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• v.32 no.3
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• pp.271-276
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• 2009

The aim of this study was to evaluate the effect of Bone Mineral Density(BMD) at mandible. So, we studied how to measure the BMD at mandible using DEXA(Dual energy X-ray absorptiometry, DEXA) by Horner er al (1996) and knew reproducibility of the measurements. Thirty-five patients (13 men, 22 women, mean age : 25.4 years) were examined using the GE Lunar Prodigy Advance(LUNAR Corporation, madison, USA). They were examined in Semiprone position of their body and true lateral position of their mandible selected the Lumbar lateral mode. We used the custom mode in analysis when ROI (area $30{\times}2.5\;mm^2$). Three ROIs ($30{\times}2.5\;mm^2$, $50{\times}2.5\;mm^2$, $20{\times}2.5\;mm^2$) were located each at the two different sites of the mandible (angle of mandible and mental symphysis) and BMD was measured. Differences in BMD measurement was statistically compared according to the size and location of ROI. BMD was $1.320{\pm}0.358g/cm^3$ in men and was $1.152{\pm}0.340g/cm^3$ in women. BMD at the angle of mandible was $1.201{\pm}0.361g/cm^3$ in men and was $1.025{\pm}0.377g/cm^3$ in women. BMD of men at the mental symphysis was $1.434{\pm}0.341g/cm^3$ and that of women was $1.19{\pm}0.358g/cm^3$. With the ROI of $20{\times}2.5\;mm^2$, BMD was $1.262{\pm}0.384g/cm^3$ in men and was $1.113{\pm}0.357g/cm^3$ in women. With the ROI of $50{\times}2.5\;mm^2$, BMD of men was $1.320{\pm}0.358g/cm^3$ and that of women was $1.129{\pm}0.340g/cm^3$. There was a statistically significant difference of BMD according to the size and location of ROI. When measuring mandible BMD, there are good for increasing ROI and locate between ramus and mental symphysis. Especially following exam, refer to same size and location with fore exam. According to study which measure mandible BMD, It's correct to measure better a portion of mandible then whole of BMD. Using DEXA protocol is studied good for the additional study to compare the BMD at mandible. Later date, It will be good for measurement value in implant and bone graft quantitatively. Using DEXA method gain BMD threshold value in korean.

• Journal of Nutrition and Health
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• v.44 no.3
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• pp.189-195
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• 2011

Vitamin K has been suggested to plays a role in bone metabolism. The objective of this study was to determine whether vitamin K2 supplementation is related to bone mineral density, bone formation markers, and bone resorption in ovariectomized (OVX) rats. Forty Sprague-Dawley female rats (body weight, $200{\pm}10$ g) were divided into four groups: a sham group fed a control diet, a sham group fed a vitamin K2 supplemented diet, OVX fed a control diet, and OVX fed a vitamin $K_2$ supplemented diet (3.5 mg vitamin $K_2$/kg diet). All rats were fed the experimental diets for 6 weeks, and deionized water was provided ad libitum. Serum alkaline phosphatase activity (ALP), osteocalcin, and urinary deoxypyridinoline crosslink values were measured as markers of bone formation and resorption. Bone mineral density (BMD) and bone mineral content were measured in the spine and femur using PIXImus (GE Lunar Co., Madison, WI, USA). No significant differences in body weight gain, food intake, or food efficiency ratio were observed between the control and experimental groups. Serum ALP, osteocalcin, and urinary crosslink values were not significantly different between the vitamin $K_2$ supplemented groups. No significant differences were observed for any of the variables in the sham group. Spine BMD values were significantly lower in the OVX than those in the sham groups. Spine and femur BMD per weight of vitamin $K_2$ tended to be higher than the control diet group within the OVX group, but no significant differences were observed. In conclusion, dietary vitamin $K_2$ supplementation may have a beneficial effect on spine and femur BMD in OVX rats. Further research is needed to understand the potential benefits of vitamin $K_2$ on bone loss in OVX rats.

• Journal of Nutrition and Health
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• v.37 no.6
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• pp.423-430
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• 2004

This study was performed to evaluate the effect of red-yeast-rice on bone metabolism in overiectomized (OVX) rats. Forty female Sprague-Dawley rats (body weight 210 $\pm$ 5 g, 9 weeks old age) were divided into two groups. One group were OVX, and the other group received sham operation (SHAM), and received either control diet (20％ casein) or a red-yeast-rice power supplemented diet (0.1％) for 9 weeks. And then each rat group was further divided into control diet (casein 20％) and red-yeast-rice powder supplemented (0.1％) diet group. All rats were fed on experimental diet and deionized water ad libitum for 9 weeks. Bone mineral density (BMD) and bone mineral content (BMC) were measured using PIXImus (GE Lunar Co, Wisconsin, USA) in spine and femur on 5, 9 weeks after feeding. The serum and urine concentrations of Ca and P were determined. Bone formation was measured by serum osteocalcin and alkaline phosphatase (ALP) concentrations. And bone resorption rate was measured by deoxypyridinoline (DPD) crosslinks immunoassay and corrected for creatinine. Serum osteocalcin, growth hormone, IGF-l and calcitonin were analyzed using radioimmunoassay kits. Urinary Ca and P excretion were not significantly different among the groups. Within the OVX group, the red-yeast-rice group had a lower crosslinks value than the casein group. Therefore the red-yeast-rice supplemented groups had a lower bone resorption ratio than the casein group in the ovariectomized rats. And, the red-yeast-rice group had significantly higher IGF-l hormone than casein group in ovariectomized rats. The red-yeast-rice group had higher spine bone mineral content than those of control group within the OVX groups. This study was an important first step in establishing that the observed beneficial effects of red-yeast-rice on bone, and this study also established the need for a study on the long-term effect of this supplement in a human.

• Journal of Korean Elementary Science Education
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• v.19 no.1
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• pp.41-56
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• 2000

The purpose of this study was to investigate the change of elementary school students' conception on the movement of the moon, after teaching a lesson about the lunar phase which focused on concrete activities. The 396 subjects in this study consisted of intact groups of second, third, fourth, fifth, and sixth grade students. Pre-test and post-test instrument concerning on the conception in the movement of the moon were developed after reviewing the related literature and curriculum. Prevailing conceptions were identified by frequency of each conception. Then, the pattern of change and consistency of each conception were analyzed in comparison pre-test with post-test. To figure out the effect of teaching, the GEFT and the GALT instrument were administered to analyze it by gender, cognition mode and level. SPSS/WIN programs were used to process the data. The result showed that teaching 'movement of the moon' was the most effective in fourth grade. The effect of teaching 'changes in shape of the moon' was effective regardless of their sexes. Teaching 'changes in shapes of the moon' was more effective for the students whose cognitive modes were field-independent, than those filed-dependent. But the improvement by the teaching was not significantly different. The pre-score by cognitive level was significantly high in the order of the formal operational, transitional stage and the concrete operational stage. But the improvement of conception after teaching was high in the order of the concrete operational, transitional stage and the formal operational stage. That is to say, teaching was more effective as the cognitive level lowered.

• Imaging Science in Dentistry
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• v.38 no.1
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• pp.29-37
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• 2008

Purpose: The aim of this study was to observe the bony change in the OVX rat longitudinally and to study the alendronate effect. Materials and Methods: Eighteen Sprague-Dewley rats, eight-week old each, were randomly assigned into three groups: one of those sham-operated (N=4), the other two were OVX: saline-treated (N=7) and alendronate-treated group (N=7). The saline-treated group was administered with saline solution (0.1mL/100g) daily, while the alendronate-treated group was given alendronate (1mg/kg, Sigma-Aldrich Corp. Korea) daily. Micro-CT scannings of the lumbar were consecutively done at baseline, at 3-week intervals during 9 weeks. Two and three dimensional bony analysis were done. Bone mineral density (BMD) was measured with Piximus (GE Lunar Co. USA). The average values of these three methods were compared with each group. Results: After 6 weeks the BMD of the OVX group showed lower tendency than that of sham group. After 6 weeks many 3D parameters of micro-CT showed higher values in the OVX-alendronate group compared with the OVXsaline group. Most 2D bony parameters were higher in the OVX-alendronate group compared with the OVX-saline group at 9 weeks. Conclusion: This study showed low BMD of the OVX group after 6 weeks and showed the effect of alendronate on the BMD and bony structures of ovariectomized rats. This study also showed usefulness of in vivo micro-CT in monitoring individual bone changes over time.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.9
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• pp.703-709
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• 2020

Pintle injector is known to have been adopted as injector of Lunar Module Descent Engine (LMDE) and contributed to success of the Apollo program and recently used in merlin engine. In this study, 500N Lab-Scale pintle injector thruster was manufactured and the combustion experiment with LOx/GCH4 was conducted. However, the proto-type thruster was showed some problems, such as low combustion efficiency and melting of pintle tip. To solve these problems, the flow guide in pintle tip was suggested through the CFD simulation. After addition of flow guide module, the combustion efficiency increased and pintle tip did not melt until the end of combustion.

• Journal of Nutrition and Health
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• v.42 no.4
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• pp.309-317
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• 2009

As far as we know, there were no studies of the effect of L-arginine on bone metabolism in post-menopausal women or ovariectomized rats. The primary objective of the current study was to determine whether arginine supplementation was associated with alterations in femoral and spinal bone mineral density (BMD) and bone markers in ovariectomized (Ovx) rats. Forty female Sprague-Dawley rats were divided into two groups, Ovx and sham groups, which were each randomly divided into two subgroups that were fed control and arginine supplemented diet. All rats were fed on experimental diet and deionized water ad libitum for 9 weeks. Bone formation was measured by serum osteocalcin and alkaline phosphatase (ALP) concentrations. Bone resorption was measured by deoxypyridinoline (DPD) crosslinks immunoassay and corrected for creatinine. Serum osteocalcin, growth hormone, insulin-like growth factor-1 (IGF-1), parathyroid hormone (PTH) and calcitonin were analyzed using radioimmunoassay kits. Bone mineral density (BMD) and bone mineral content (BMC) were measured using PIXImus (GE Lunar Co, Wisconsin, USA) in spine and femur. The serum and urine concentrations of Ca and P were determined. The plasma was analyzed for arginine. Diet did not affect weight gain, mean food intake, and plasma arginine concentration. Urinary Ca excretion was decreased by arginine supplementation in Ovx rats, but statistically not significant. The Ovx rats fed arginine-supplemented diet were not significantly different in ALP, osteocalcin, crosslinks value, PTH, calcitonin and IGF-1 compared to those fed control diet. The arginine-supplemented group had significantly higher serum Ca and growth hormone than control group. Spine and femur BMD were significantly increased by arginine supplementation on 5th and 9th weeks after feeding. Our findings indicate that dietary L-arginine supplementation decreased bone mineral density loss in Ovx rats. Therefore, dietary arginine supplementation may represent a potentially useful strategy for the management of osteoporosis.

• Ocean Science Journal
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• v.42 no.2
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• pp.103-116
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• 2007

Seasonal changes of tide signal(s), temperature, salinity and current were studied during the years 2004-2005 in the northernmost Gulf of Aqaba, which is under developmental activities, to obtain scientific bases for best management and sustainability. Spectrum analysis revealed permanent signals of tide measurements during all seasons, which represented semidiurnal and diurnal barotropic tides. The other signal periods of 8.13, 6.10-6.32, 4.16 and 1.02-1.05 h were not detected in all seasons, which were related to shallow water compound and overtides of principle solar and lunar constituent and to seiches generated in the Red Sea and the Gulf of Aqaba. Spatial and temporal distribution of temperature, salinity and density showed significant differences between months in the coastal and offshore region and no significant differences among the coastal sites, between the surface and bottom waters and between coastal and offshore waters. Therefore, the temporal and spatial variation of water properties in the northernmost Gulf of Aqaba behave similarly compared to other parts. The coastal current below 12 m depth was weak $(3-6\;cms^{-1})$ and fluctuated from east-northeastward to west-southwestward (parallel to the shoreline), which may be related to the effect of bottom topography and/or current density due to differential cooling between eastern and western parts in the study area, and wind-induced upwelling and downwelling in the eastern and western side, respectively. The prevailing northerly winds and stratification conditions during summer were the main causes of the southward current at 6 and 12 m depths with average speed of 28 and $12cms^{-1}$ respectively.

• Journal of Community Nutrition
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• v.6 no.1
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• pp.48-54
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• 2004

The purpose of this study was to examine the effects of dietary protein and exercise on bone mineral density and bone mineral content of growing male rats. Forty male, Sprague-Dawley rats(age 21 days) were assigned to four groups that underwent 9 weeks of experimental treatment. Animals were assigned to one of two exercise treatments (treadmill running or sedentary). The exercise and nonexercise group were fed a diet containing casein or soy with rich isoflavones (3.4mg/g protein). The exercise group ran on a rodent treadmill(speed of 15m/min for 30min) three days per week during the 9-week study period. All rats were fed an experimental diet and deionized water ad libitum for 9 weeks. Total bone mineral density (BMD), total bone mineral content (BMC), total body calcium, spine BMD and BMC, and femur BMD and BMC were determined by using dual energy x-ray absorptiometry (FIXI-mus, GE Lunar Radiation Cooperation, Madison, WI, USA). The soy diet group appears to have a significantly higher total BMD/weight and total BMC/ weight, spine BMD/weight, spine BMC/weight, femur BMD/weight and femur BMC/weight compared to the casein group in nonexercise and exercise. The exercise group had significantly greater total BMD/weight and BMC/ weight, spine BMD/weight and BMC/weight, femur BMD/weight and BMC/weight compared to the nonexercise group when the protein source was casein. The exercise combined soy group had significantly greater total BMD/weight and BMC/weight, spine BMD/weight and BMC/weight, femur BMD/weight and BMC/weight, compared to the exercise combined casein group. The results indicate that exercise had a positive influence on bone mineral density and bone mineral content and soy significantly affect on bone mineral density and bone mineral content for the 9 weeks experimental period. It can be concluded that exercise combined with a soy diet is most beneficial for acquisition of spine bone mineral density in young growing male rats. This convincing evidence suggests that a change in life style such as increasing exercise and consumption of soy protein is a practical strategy for significantly reducing the incidence of osteoporosis.