• Journal of Astronomy and Space Sciences
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• 제27권4호
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• pp.329-335
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• 2010

We investigate the sources of the variation of the high-latitude thermospheric neutral mass density depending on the interplanetary magnetic field (IMF) conditions. For this purpose, we have carried out the National Center for Atmospheric Research Thermosphere-Ionosphere Electrodynamics General Circulation Model (NCAR-TIEGCM) simulations for various IMF conditions under summer condition in the southern hemisphere. The NCAR-TIEGCM is combined with a new empirical model that provides a forcing to the thermosphere in high latitudes. The difference of the high-latitude thermospheric neutral mass density (subtraction of the values for zero IMF condition from the values for non-zero IMF conditions) shows a dependence on the IMF condition: For negative $B_y$ condition, there are significantly enhanced difference densities in the dusk sector and around midnight. Under the positive-$B_y$ condition, there is a decrease in the early morning hours including the dawn side poleward of $-70^{\circ}$. For negative $B_z$, the difference of the thermospheric densities shows a strong enhancement in the cusp region and around midnight, but decreases in the dawn sector. In the dusk sector, those values are relatively larger than those in the dawn sector. The density difference under positive-$B_z$ condition shows decreases generally. The density difference is more significant under negative-$B_z$ condition than under positive-$B_z$ condition. The dependence of the density difference on the IMF conditions in high latitudes, especially, in the dawn and dusk sectors can be explained by the effect of thermospheric winds that are associated with the ionospheric convection and vary following the direction of the IMF. In auroral and cusp regions, heating of thermosphere by ionospheric currents and/or auroral particle precipitation can be also the source of the dependence of the density difference on the IMF conditions.

• 한국수산과학회지
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• 제42권4호
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• pp.354-359
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• 2009

The productivity of ultra-small rotifer, Synchaeta kitina was investigated at the exchange rate of culture water (10, 20, 30, 40 and 50%) and initial inoculation densities (250, 600 and 900 inds. per mL) in semi-continuous culture. Also, the possibility of mass culture was investigated in a 100 L culture tank. Tetraselmis suecica was used as the feed for S. kitina in all experiments. The production of S. kitina increased with an increase in exchange rate of culture water. The highest production ($82.0{\times}10^5$ inds.) was achieved at 40% exchange rate of culture water. The production of S. kitina increased with an increase of initial inoculation density during the first week and the highest total production ($17.4{\times}10^6$ inds.) was achieved at 900 inds. per mL of initial inoculation density. However, on the second week, all treatments were not significantly different in total production (P>0.05). During the two weeks, total production of S. kitina at 900 inds. per mL of initial inoculation density was higher than at 600 inds. of initial inoculation density, but there was no significant difference (P>0.05). In the 100 L culture tank, density of S. kitina was kept from 516 to 890 inds. per mL and S. kitina was daily harvested $15.5{\times}10^6$ to $26.7{\times}10^6$ during the experimental period. The production cost for 100 million rotifers in semi-continuous culture was 63,656 won. The results from this study indicate that the optimal exchange rate of culture water and initial inoculation density for the semi-continuous culture of ultra-small rotifer, S. kitina are 40% and 600 inds. per mL, respectively.

• 대한영양사협회학술지
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• 제11권1호
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• pp.86-94
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• 2005

This study was conducted to examine bone mineral density and factors which effect on bone mineral density such as daily nutrients intake, age, menarch age and physical condition among healthy female college students in Daegu area from April 20, to May 20, 2004. 1. Average age was 20.5$\pm$0.96 years old, average height was 160.9$\pm$4.30㎝, and average weight was 55.9$\pm$7.67㎏. Body mass index was 21.6$\pm$2.91㎏/㎡, body fat was 25.6$\pm$5.79％, menarche age was average 12.5$\pm$1.1 years old and WHR(waist/hip circumference ratio) was 0.8$\pm$0.01㎝/㎝. 2. Average level of bone mineral density(T-score -0.56$\pm$0.91) was in normal range. But, 11 persons(24.4％) are over T-score -1.0, 33 persons(73.4％) were within -1.0 - -2.5 and one person(2.2％) was under -2.5. It is very anxious level for Osteopenia-low bone mass, as research result shows 73.4% of the subject of examine on the level of Osteopenia. 3. Daily calorie intake was 2,550㎉ and each nutrient intake, compared to the seventh recommended dietary allowances for korean, was as follows ; Calorie 112％, protein 123％, calcium 78％, phosphorus 137％, iron 68％, vitamin A 101％, vitamin $B_1$ 141％, vitamin $B_2$ 95％, niacin 107％, vitamin C 128％ and zinc 120％. The ratio of calcium to phosphorus(Ca/P) is 0.66, low compared to RDA, but phosphorus intake is so high compared to RDA that precautions should be taken. The ratio of calcium to protein(Ca/Protein) is 8.55. 4. Menarche age and bone mineral density of calcaneus showed positive correlation and body mass index(BMI) indicated positive correlation. Age, height, weight. WHR and physical activity coefficient all do not indicate any significant correlation with bone mineral density. 5. Intake of Calorie, Ca, Ca/p ratio, carbohydrate and fat intake were positively correlated and, protein was negatively correlated, and Fe, Na, P and cholesterol were negatively correlated with BMD. These results indicate that average bone mineral density of subjects was in normal range, but subjects in the stage of osteopenia-low bone mass are many and bad effects are expected to have on their bone mineral density after menopause. Therefore, in order reach maximal bone mineral density, they should improve the balance between calcium and phosphorus and reduce salt intake. And it is thought that education and profound studies on relevant factors affecting the genesis of bone mineral density should be made.

• 한국환경복원기술학회지
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• 제14권3호
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• pp.47-55
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• 2011

Cicada is a very familiar insect to people but habitat characteristics of them are not well known. To investigate habitat characteristics of cicada nymph, plant species, plant cover, soil hardness, accumulated organic mass, organic content in soil, and root density were investigated at 11 sites in an apartment complex garden in Seoul. Selected sites had different densities of cicada nymph case above the ground. Density of cicada nymph case was positively correlated with accumulated organic mass, organic content in soil, and root density and negatively correlated with soil hardness. Even though shrub coverage was not linearly correlated with the density of cicada nymph case, 80% cover of shrub was necessary for the high density of them. Data in this study suggested that organic matter in addition to root density be the primary limitation factor of cicada nymph and high amount of litter-fall decrease soil hardness through the increase of soil organic matter. This study suggests that the density of cicada nymph can be managed through organic content in soil.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.470-470
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• 2010

Negative ions are generated in fusion edge plasmas, material processing plasmas, ionospheric plasmas. Analytic formulas for the deduction of the absolute density of negative ions was given by using the current-voltage(IV) characteristics of two electric probes at two different pressures [1], and negative ion density has been measured by one electric probe using the current-voltage characteristics of three different pressures [2]. Ratios of ion and electron saturation currents and electron temperatures and sheath areas of different pressures are usually incorporated into two equations with two unknowns for the negative ion density. In the previous publications, the sheath factor(sheath area, sheath density, sheath velocity) and effective masses of background ions with different pressures are qualitatively incorporated for the deduction of negative density. In this presentation, the quantitative and detailed relation of negative ion density with sheath factor and effective masses are going to be given. The effect of these parameters on the change of IV characteristics will be addressed.

• Clinical and Experimental Reproductive Medicine
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• 제19권1호
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• pp.49-56
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• 1992

Bone mineral density was measured to assess whether the patients with premonopausal hypogonadism, comprised of 19 patients with hypogonadotropic hypogonadism(HH), 55 with premature ovarian failure(POF), 23 with hyperprolactinemia(HPLN), and 8 with Sheehan's syndrome. All aged from 20 to 39, were associated with some decrease in regional bone mass compared with that of 63 normal-associated with some decrease in regional bone mass compared with that of 63 normal-cycling control women matched with age and sex. Measurement of bone mineral density was carried out using Dual photon absorptiometry at four sites; femur neck, ward's triangle, trochanter and spine(L2-L4). Bone mineral density at all four sites were significantly decreased in patients with HH(p<0.01), POF(p<0.01). In hyperprolactinemic patients, the decrease in bone mass was significant at femur neck and Ward's triangle(p<0.05). The patients with POF were noted to be associated with significant bone loss when their duration of amenorrhea exceeded one year. In this study, the degree of loss of bone mass and the affected sites seemed to be different depending on the various types of hypogonadism and POF was noted have caused the appearance of loss of bone mass earlier than other thpes of hypogondism we experienced.

• Journal of Radiation Protection and Research
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• 제41권4호
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• pp.378-383
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• 2016

Background: Radiation dose rates in PRIDE facility is evaluated quantitatively for assessing radiation safety of workers because of large amounts of depleted uranium being handled in PRIDE facility. Even if direct radiation from depleted uranium is very low and will not expose a worker to significant amounts of external radiation. Materials and Methods: ORIGEN-ARP code was used for calculating the neutron and gamma source term being generated from depleted uranium (DU), and the MCNP5 code was used for calculating the neutron and gamma fluxes and dose rates. Results and Discussion: The neutron and gamma fluxes and dose rates due to DU on spherical surface of 30 cm radius were calculated with the variation of DU mass and density. In this calculation, an imaginary case in which DU density is zero was added to check the self-shielding effect of DU. In this case, the DU sphere was modeled as a point. In case of DU mixed with molten salt of 50-250 g, the neutron and gamma fluxes were calculated respectively. It was found that the molten salt contents in DU had little effect on the neutron and the gamma fluxes. The neutron and the gamma fluxes, under the respective conditions of 1 and 5 kg mass of DU, and 5 and $19.1g{\cdot}cm^{-3}$ density of DU, were calculated with the molten salt (LiCl+KCl) of 50 g fixed, and compared with the source term. As the results, similar tendency was found in neutron and gamma fluxes with the variation of DU mass and density when compared with source spectra, except their magnitudes. Conclusion: In the case of the DU mass over 5 kg, the dose rate was shown to be higher than the environmental dose rate. From these results, it is concluded that if a worker would do an experiment with DU having over 5 kg of mass, the worker should be careful in order not to be exposed to the radiation.

• 대한의생명과학회지
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• 제16권3호
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• pp.169-177
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• 2010

Osteoporosis is a disease that increases the fracture rates and a major cause of increased mortality and morbidity in the elderly people. This study is to determine which components of body composition and metabolic syndrome risk factors are important to bone health, we analysed the relationship among bone mineral density (BMD), body composition and metabolic syndrome risk factors in females. Totally 630 females participated in a medical check-up program (mean age 47 years) were selected for this study. Body composition analysis was performed by segmental bioelectrical impedance method, muscle mass, and percent body fat were measured. We also measured metabolic syndrome risk factors including abdominal obesity, HDL-cholesterol, triglyceride, blood pressure and fasting glucose level. Metabolic syndrome was defined by NCEP-ATP III criteria. The lumbar spine and femoral neck BMD were measured using the dual energy X-ray absorptiometry. Osteopenia and osteoporosis were observed in 180 and 51 persons, respectively. Muscle mass and HDL-cholesterol decreased in osteopenia and osteoporosis groups compared to the control group, and the grade was shown progressively by the symptoms. Significant positive correlation between BMD and muscle mass was observed. Multi variable regression analyses showed that % body fat and muscle mass were independent predictors of BMD after adjustment of age, height and weight. In conclusion, the BMD showed negative correlation with the metabolic and body composition was associated with BMD.

• Journal of Microbiology and Biotechnology
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• 제19권12호
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• pp.1603-1611
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• 2009

High-cell-density cultivation of yeast was investigated using the agricultural waste products corn steep liquor (CSL) and molasses. The Saccharomyces cerevisiae KV-25 cell mass was significantly dependent on the ratio between C and N sources. The concentrations of molasses and CSL in the culture medium were statistically optimized at 10.25% (v/v) and 16.87% (v/v), respectively, by response surface methodology (RSM). Batch culture in a 5-l stirred tank reactor using the optimized medium resulted in a cell mass production of 36.5 g/l. In the fed-batch culture, the feed phase was preceded by a batch phase using the optimized medium, and a very high dried-cell-mass yield of 187.63 g/l was successfully attained by feeding a mixture of 20% (v/v) molasses and 80% (v/v) CSL at a rate of 22 ml/h. In this system, the production of cell mass depended mainly on the agitation speed, the composition of the feed medium, and the glucose level in the medium, but only slightly on the aeration rate.

• 한국식품영양학회지
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• 제24권4호
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• pp.786-796
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• 2011

The purpose of this study was to investigate the relationship between bone mineral density(BMD), body composition and life styles of female college students. The subjects were 334 students with a mean age of 21.0 years. BMDs of forearm and calcaneus were measured by dual energy X-ray absorptiometry, and body composition was measured by bioelectrical impedence analysis. The means for weight, height, and body mass index(BMI) of the subjects were 55.7 kg, 161.0 cm, 21.5 kg/$m^2$, respectively. Grouping by the BMI, 13.2% of the subjects were classified as overweight, and 11.1% of the subjects as obese group. BMD in the forearm and calcaneus were 0.390 g/$cm^2$, 0.514 g/$cm^2$. In the forearm, 58.1% and 9.6% of the subjects were classified as osteopenia and osteoporosis, respectively, and in the calcaneus, 12.0% and 0.3% of the subjects were classified as osteopenia and osteoporosis, respectively. Body weight, skeletal muscle mass, lean body mass, fat mass and BMI were positively correlated with BMDs in the forearm and calcaneus($r$=0.180~0.495, $p$ <0.01~0.001), and height, % body fat and waist-hip ratio(WHR) were positively correlated with BMDs in the calcaneus($r$=0.213~0.239, $p$ <0.001), but not in the forearm. The factors such as beginning age of cigarette smoking and alcohol drinking and exercise had significant influence on BMD($p$ <0.05; p<0.001), whereas sleeping hours, activity level, frequency of exercise, meal times, frequency of snack and fried food intake, breakfast skipping and amount of meal had not significant influence on BMD. Therefore, the acquisition of balanced body composition is necessary through the increase of fat free mass and muscle mass, not through the increase of fat mass among female college students.