• 한국식품영양학회:학술대회논문집
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• 한국식품영양학회 2003년도 하계 학술 심포지엄
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• pp.76-76
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• 2003

This study was conducted to investigate dietary and other factors affecting bone mineral density (BMD) in Korean premenopausal women. Seventy-eight premenopausal women who visited health promotion center for health examinations volunteered to participate in this study and they were divided into two groups according to the bone status by T-score : normal or osteopenic group and osteoporotic group. The demographic and general characteristics, and dietary intake were surveyed using the questionnaire. BMDs of the lumbar spine and femoral neck of subjects were measured by dual energy X-ray absorptiometry. Serum samples were measured for Lipid concentration, and calcium, phosphorus, alkaline phosphatase as bone formation indicators. Urine was analysed for creatinine as bone resolution indicators. The results are as follows:The mean BMDs of the lumbar spine and femoral neck were 1.21 0.02g/cm$^2$ and 0.97 0.04g/cm$^2$, respectively and the BMD levels of osteoporotic group were significantly lower than that of normal or osteopenic group (p<0.001, respectively). Height in osteoporotic group was significantly lower than that of normal or osteopenic group (p<0.01), and bodyweight did not show any significant difference but had a lower tendency. Mean daily intake of energy was 1720 52ka1. When nutrient intake was compared with recommended dietary allowances (RDA) of subjects, calcium, Fe, vitamin A and riboflavin intakes showed means lower than RDA. The nutrient intake did not show any significant difference between normal or osteopenic group and osteoporotic group except intakes of protein fat and niacin. Serum and urine levels did not show any significant differences between normal or osteopenic group and osteoporotic group and all were within normal range, however, serum alkaline phosphatase level of osteoporotic group was significantly higher than that of normal or osteopenic group (p<0.001). Height showed positive correlations with lumbar spine bone mineral density (LBMD, r=0.332, p<0.01), no correlation was found with femoral neck bone mineral density (NBMD). Age, age at menarche, bodyweight, body mass index (BMI) and obesity showed no correlation with BMD. The BMD of the lumbar spine was significantly and positively related to the intake of niacin and vitamin C (r=0.236, p<0.05; r=0.274, p<0.05). Serum levels of calcium and phosphorus showed a negative correlation with LBMD (r=-0.698, p=0.0001; r=-0.503, p=0.0001, respectively). The results suggested that the BMDs of the lumbar spine was positively related to the intake of niacin and vitamin C in premenopausal women. Therefore, this study confirmed that one of the most effective way to minimize bone loss would be higher intake of niacin and vitamin C rich foods and habitual physical activity may have a beneficial effect on BMD in premenopausal period.

• Journal of Nutrition and Health
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• 제31권9호
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• pp.1446-1456
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• 1998

Bones are important parts in sustaining the shape of the body, but they are also metabolic organs which undergo bone remodeling by constant bone resorption and formation. Osteoporosis, the typical metabolic bone disease, is characterized by a reduction in bone mineral density (BMD). Women more than men are at risk fir osteoporosis-related fractures, especially in the lumbar spine, wrist, and hip region. Risk of fracture depends on one's BMD, which open determined by the peak bone mass value achieved at skeletal maturity and followed by subsequent age-and menopause-related bone loss. Genetic and environmental factors are known to play a key role in bone metabolism and diet is considered as one of the important environmental factors. The purpose of the present study was to assess the status of BMD and bone mineral content(BMC) to clarify the relationships between dietary intakes and the risk of osteoporosis in adult women in Taegu. Subjects were 130 healthy females in between 20 and 69 years of age. BMD and BMC of the lumbar spine(venebrae L2-4) of the subjects were measured by dual energy X-ray absorptiometry. The average age of the subjects was 47.4${\pm}$11.7 years old, the average weight was 57.2${\pm}$8.4kg, the average age of menarche was 16.6${\pm}$1.9 years old and the average age of menopause was 48.4${\pm}$5.3 years old. The nutrient intakes of the subjects measured by the convenient method were generally lower than the level of RDA. The result of nutrient intake assessed has shown that the average energy intake was 1701${\pm}$316kca1 which is 85.1% of the RDA and the average calcium intake was 485.4${\pm}$172.3mg which is 69.3% of the RDA. The intakes of protein, vitamin A, vitamin B$_1$, niacin were greater than the RDA, whereas the remaining nutrient intakes were lower than the RDA. The average BMD of the subjects was shown to be 1.06${\pm}$1.09g/$\textrm{cm}^2$. The highest BMD of 1.24${\pm}$0.14g/$\textrm{cm}^2$ was noticed in the subjects of 30s compared to 20s, 40s, 50s, 60s. The BMD values were compared by the relative body weight(R3W) of the menopause subjects, and it was found that the underweight group had significant lower BMB while the rest of the groups did not have any differences in BMD. The most strongly correlated nutrient with BMD among the menopause subjects appeared to be calcium. The women whose Ca intakes were higher than 500mg showed the significantly higher BMD than those with Ca intakes lower than 500mg. This study suggests that the most effective way to prevent osteoporosis and to reduce the incidences of fractures seems to be minimizing bone loss through the adequate intake of calcium as well as avoiding underweight, especially in menopausal women. (Korean J Nutrition 31(9) . 1446-1456, 1998)

• 한국대기환경학회지
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• 제34권5호
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• pp.727-734
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• 2018

In this study, real-time absorption coefficients of carbonaceous species in $PM_{2.5}$ was observed using a dual-spot 7-wavelength Aethalometer between November 1, 2016 and December 31, 2017 at an urban site of Gwangju. In addition, 24-hr integrated $PM_{2.5}$ samples were simultaneously collected at the same site and analyzed for organic carbon and elemental carbon (OC and EC) using the thermal-optical transmittance protocol. A main objective of this study was to estimate mass absorption cross section (MAC) values of black carbon (BC) particles at the study site using the linear regression between aethalometer-based absorption coefficient and filter-based EC concentration. BC particles observed at 880 nm is mainly emitted from combustion of fossil fuels, and their concentration is typically reported as equivalent BC concentration (eBC). eBC concentration calculated using MAC value of $7.77m^2/g$ at wavelength of 880 nm, which was proposed by a manufacturer, ranged from 0.3 to $7.4{\mu}g/m^3$ with an average value of $1.9{\pm}1.2{\mu}g/m^3$, accounting for 7.3% (1.5~20.9%) of $PM_{2.5}$. The relationship between aerosol absorption coefficients at 880 nm and EC concentrations provided BC MAC value of $15.2m^2/g$, ranging from 11.4 to $16.2m^2/g$. The eBC concentrations calculated using the estimated MAC of $15.2m^2/g$ were significantly lower than those reported originally from aethalometer, and ranged from 0.2 to $3.8{\mu}g/m^3$, with an average of $1.0{\pm}0.6{\mu}g/m^3$, accounting for 3.7% of $PM_{2.5}$ (0.8~10.7%). Result from this study suggests that if the MAC value recommended by the manufacturer is applied to calculate the equivalent BC concentration and radiative forcing due to BC absorption, they would result in significant errors, implying investigation of an unique MAC value of BC particles at a study site.

• Journal of Nutrition and Health
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• 제39권5호
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• pp.451-459
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• 2006

The purpose of our study was to evaluate an association between milk consumption and bone mineral density (BMD) of female college students in Korea. The dietary data of 1,410 Korean college students living in the vicinity of Seoul area were collected through the Food Frequency Questionnaire. The mean age, height, weight and 8MI of the subjects were 20.4 years, 162.1 cm, 52.7 kg, and $20.0\;kg/m^2$ respectively. The mean intakes of energy, protein, and phosphorus were 2,398.7 kcal, 95.2 g, and 1,302.9 mg respectively, which were above their EER or Recommended Intake (RI), but the mean intake of calcium was 657.8 mg which was below its RI, and 44.0% of the subjects did not meet Estimated Average Requirement (EAR) of calcium. The daily milk consumption was 131.1 g, and the total consumption of milk and dairy product was 228.7 g. Forty five percent of the subjects consumed $50{\sim}200\;g$ of milk or dairy products. After the analysis of their dietary intakes, the subjects were divided into quintiles of total consumption of milk and dairy product, which were considered as major source of dietary calcium. Ninety two subjects from the upper quintile (UQ) and 85 subjects from the lower quintile (LQ) were selected and their bone mineral densities (BMD) of lumbar spine (L1-L4) and the femur were examined by the dual energy X-ray absorptiometry. The BMD $(g/cm^2)$of L1, L2, L3, and average of femur were 1.065, 1.150, 1.187, and 0.988 for the UQ subjects, which were significantly higher than those of the LQ subjects, 1.010, 1.090, 1.146, and 0.942 respectively. Moreover, the T-scores of the UQ were significantly higher than those of the LQ. The prevalence rates of osteopenia classified according to WHO's criterion were 12.0% in the UQ. and 20.0% in the LQ group which showed non significant. Blood levels of calcium, and phosphorus of UQ and LQ group were both within the normal range, and were not significantly different. Our results showed that UQ group presented the better status of bone mineral density and bone health. Therfore our results suggest that continuous consumption of more than one and a half cups of milk per day, which corresponds to the least amount of UQ group's consumption, would affect positively on the bone health of Korean adults.

• Journal of Nutrition and Health
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• 제39권5호
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• pp.485-493
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• 2006

The purpose of this study was to investigate the relationships among nutrient intakes, BMD, serum copper, zinc and manganese contents in Korean postmenopausal women residing in Seoul and Kyunggi-do. Nutrient intakes analyses and anthropometric measurements were performed for 64 postmenopausal women. Also, fasting blood samples were collected. The BMDs of the lumbar spine (L2-L4) and femoral neck were measured by dual energy X-ray absorptiometry (DEXA). Subjects were classified into three groups: osteoporosis (T-score ${\leq}$ -2.5, n = 20), osteopenia (-2.5 < T-score ${\leq}$ -1, n = 24), and normal (T-score) -1, n = 20). The results are summarized as follows; the mean age, height and weight were 62.1 yrs, 153.8 em, and 56.1 kg, respectively, with no significant difference among three groups. On the other hand, the mean BMI $(23.7\;g/m^2)$ of normal group was significantly higher than those of other two groups. The mean energy intake was 1,395.3 kcal (77.5% of Dietary referance intakes for koreans (KDRls)). The average daily intakes of vitamin $B_2$, calcium and zinc did not reach KDRIs. The mean intakes of iron, copper, zinc and manganese were 10.9 mg, 1.6 mg, 7.8 mg and 5.1 mg respectively, with no significant difference among three groups, The mean serum levels of copper, zinc and manganese were 96.4 mg/dl, 91.5 mg/dl and 39.5 ng/dl, respectively with no significant differences among three groups. The BMD of lumbar spine showed a significantly negative correlation intakes of animal protein, fat and iron intakes after adjusting for age, Bill. However, the BMD of lumbar spine was not significantly correlated with animal iron intakes after adjusting for animal protein, and fat intakes, indicating animal food intake is a possible confounding factor. Proper intakes of vitamin $B_2$, vitamin C are required to protect osteoporosis in postmenopausal women. These results suggest that excessive animal food intakes may have adverse effect on bone mineral density. Further studies arc necessary to elucidate the role of serum minerals in BMD.

• 대한전자공학회논문지SD
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• 제43권11호
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• pp.83-89
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• 2006

본 논문에서는 무선통신용 송수신기에 집적화할 수 있도록 $0.35{\mu}m$ CMOS n-well 1-poly 4-metal 공정을 이용하여 3.3V의 전원 전압으로 동작하는 I/Q 채널 12비트 120MHz 전류구동 D/A 변환기를 설계하였다. 설계된 12비트 D/A 변환기는 4비트 온도계 디코더를 3단 구성하여 글리치 에너지와 선형오차 특성을 최소화하였다. 측정된 선형오차인 INL/DNL은 각각 ${\pm}1.5LSB$, ${\pm}1.3LSB$이며, 글리치 에너지는 31pV.s 로 측정되었고, 전력소모는 105mW이다. 샘플링 및 입력주파수가 각각 120MHz, 1MHz일 때, 싱글 톤 테스트에서 유효비트수는 10.5비트로 측정되었다. 듀얼 톤 테스트에서 1MHz/1.1MHz의 기저대역신호는 0.9MHz/1.2MHz의 영상신호 차이가 -63dB 나타나는 것으로 측정되었다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.36-36
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• 2017

Out of twenty common protein amino acids, there are many kinds of non protein amino acids (NPAAs) that exist as secondary metabolites and exert ecological functions in plants. Mimosine (Mim), one of those NPAAs derived from L. leucocephala acts as an iron chelator and reversely block mammalian cell cycle at G1/S phases. Cysteine (Cys) is decisive for protein and glutathione that acts as an indispensable sulfur grantor for methionine and many other sulfur-containing secondary products. Cys biosynthesis includes consecutive two steps using two enzymes-serine acetyl transferase (SAT) and O-acetylserine (thiol)lyase (OASTL) and appeared in plant cytosol, chloroplast, and mitochondria. In the first step, the acetylation of the ${\beta}$-hydroxyl of L-serine by acetyl-CoA in the existence of SAT and finally, OASTL triggers ${\alpha}$, ${\beta}$-elimination of acetate from OAS and bind $H_2S$ to catalyze the synthesis of Cys. Mimosine synthase, one of the isozymes of the OASTLs, is able to synthesize Mim with 3-hydroxy-4-pyridone (3H4P) instead of $H_2S$ for Cys in the last step. Thus, the aim of this study was to clone and characterize the cytosolic (Cy) OASTL gene from L. leucocephala, express the recombinant OASTL in Escherichia coli, purify it, do enzyme kinetic analysis, perform docking dynamics simulation analysis between the receptor and the ligands and compare its performance between Cys and Mim synthesis. Cy-OASTL was obtained through both directional degenerate primers corresponding to conserved amino acid region among plant Cys synthase family and the purified protein was 34.3KDa. After cleaving the GST-tag, Cy-OASTL was observed to form mimosine with 3H4P and OAS. The optimum Cys and Mim reaction pH and temperature were 7.5 and $40^{\circ}C$, and 8.0 and $35^{\circ}C$ respectively. Michaelis constant (Km) values of OAS from Cys were higher than the OAS from Mim. Inter fragment interaction energy (IFIE) of substrate OAS-Cy-OASTL complex model showed that Lys, Thr81, Thr77 and Gln150 demonstrated higher attraction force for Cys but 3H4P-mimosine synthase-OAS intermediate complex showed that Gly230, Tyr227, Ala231, Gly228 and Gly232 might provide higher attraction energy for the Mim. It may be concluded that Cy-OASTL demonstrates a dual role in biosynthesis both Cys and Mim and extending the knowledge on the biochemical regulatory mechanism of mimosine and cysteine.

• 대한지역사회영양학회지
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• 제13권3호
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• pp.418-425
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• 2008

The purpose of this study was to investigate correlations between bone mineral density (BMD) and dietary and non-dietary factors in female college students. The BMD of the subjects (n = 38) was measured using DEXA (Dual Energy X-ray Absorptiometry) at lumbar spine and three femoral sites including femoral neck, ward's triangle, and femoral trochanter. Three-day 24-hour dietary recall data were collected from each subject to assess consumption levels of nutrients and food groups. The mean (${\pm}SD$) values of age, age of menarche, height, weight, body mass index (BMI), waist-to-hip ratio (WHR), fat mass, and % body fat of the subjects were 21.34 (${\pm}1.73$) years, 13.1 (${\pm}1.2$) years, 161.3 (${\pm}5.0$) cm, 53.7 (${\pm}7.2$) kg, 20.6 (${\pm}2.6$) $kg/m^2$, 0.80 (${\pm}0.04$), 15.4 (${\pm}4.4$) kg, and 28.2 (${\pm}4.7$), respectively. The BMD values of lumbar spine, femoral neck, ward's triangle, and femoral trochanter as T-value were $1.150{\pm}0.13\;g/cm^2$, $0.932{\pm}0.11\;g/cm^2$, $0.850{\pm}0.13\;g/cm^2$, and $0.721{\pm}0.10\;g/cm^2$, respectively. The daily mean energy intake of the subjects was 1660.6 kcal. The intake levels of carbohydrate, calcium, iron, vitamin C, and folic acid were lower than the KDRIs, while those of fat, phosphorus, sodium, vitamin A, and vitamin $B_6$ were higher than the KDRIs. Significantly negative correlation were detected between consumption of fat and oils and the BMD of all sites measured (p < 0.05). Potato and starch intake was negatively correlated to the BMD of femoral neck and word's triangle (p < 0.05). The intake of cereals was found to be negatively correlated to the BMD of ward's triangle (p v 0.05). There was also negative correlation of intake of soybeans and products with the BMD of lumbar spine (p < 0.05). Weight and muscle mass were positively correlated to the BMD of both lumbar spine and femurs (p < 0.01). Significantly positive correlations between BMI, and fat mass and the BMD of lumbar spine were observed (p < 0.001). Additionally fat mass was positively correlated to the BMD of femoral neck. WHR and % body fat were positively correlated to the BMD of lumbar spine (p < 0.05). Negative correlation was found between a serum calcium level and the BMD of femoral neck (p < 0.05). In summary non-dietary factors generally showed significant correlations with the BMD of lumbar spine, while several dietary factors showed significant correlations with the BMD of femurs.

• 한국농림기상학회지
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• 제11권4호
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• pp.233-246
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• 2009

증발산(ET)을 증발(E)과 증산(T)으로 배분하는 것은 물 순환과 에너지, 물 및 탄소 순환의 연결고리를 이해하는 데에 매우 중요하다. 산림 군락의 총 증발산은 상부 및 하부 군락의 증산과 토양 및 차단 강수로부터의 증발로 구성된다. 이들의 상대적 기여도를 정량화하기 위해, 에디 공분산 방법을 사용하여 2008년 6월 1일부터 2009년 5월 31일까지 광릉 활엽수림과 침엽수림의 마루에서의 증발산을 관측하였다. 스펙트럼 분석에 따르면, 초음파 풍향 풍속계와 수증기 농도 측정기 사이의 거리에 의한 증발산 과소 평가는 군락 하부에서 연간 증발산량의 약 10%정도였다. 하부군락의 연간 증발산은 활엽수림과 침엽수림에서 각각 59mm와 43mm로, 총 증발산량의 16%와 7%를 차지하였다. 전반적으로 식생면적지수가 최대인 여름 기간을 제외하고는 하부군락의 증발산은 총 증발산에서 무시할 수 없는 부분을 차지하였다. 두 산림지역의 비결합 모수($\Omega$)는 약 0.15이었으며, 이는 하부군락의 증발산이 주로 포차나 토양 수분에 의해서 조절됨을 보여준다. 두 산림의 하부 군락의 증발산의 차이는 군락 하부의 환경 조건의 차이에 기인하며, 특히 습도와 토양 수분의 차이로 인해 발생하였다. 광릉 하부 군락의 증발산 기여도가 작지 않다는 사실은 이러한 산림의 물질과 에너지 플럭스를 해석하고 모델링하기 위해서는 이원 또는 다층 모형이 필요함을 시사한다.

• 대한기계학회논문집B
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• 제38권12호
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• pp.1057-1064
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• 2014

최근 전세계적으로 재생에너지의 관심이 증가하고 있다. 그 중 많은 관심을 받고 있는 것이 상대적으로 낮은 온도의 폐열을 사용하는 유기랭킨사이클(ORC)이다. 유기랭킨사이클은 기존의 증기터빈사이클과 유사한 기술을 사용하지만 낮은 온도의 폐열을 사용하기 위해서 증기대신 냉매를 작동유체로 사용한다. 작동유체를 냉매로 사용함으로 인해 이상기체 가정을 사용할 수 없고, 이는 ORC 시스템에 이용되는 터빈의 설계를 좀 더 복잡하게 만든다. 또, 냉매의 큰 분자량과 복잡한 분자구조로 인하여 낮은 음속을 가지게 되고 이로 인해서 쉽게 초킹 조건에 접근하게 된다. 본 연구에서 R245fa를 작동유체로 하여 입구온도 $124^{\circ}$에 팽창비 9 의 조건에서 터빈의 효율을 증가시키기 위해 다단으로 설계된 아음속 ORC 터빈을 설계하는 과정과 터빈의 성능에 대하여 설명하고자 한다. 설계된 터빈은 200kW 급의 ORC 발전 시스템에 사용될 예정이다.