• Korean Journal of Poultry Science
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• v.16 no.2
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• pp.91-100
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• 1989

This study was conducted to observe 1) the changes of cellular association in seminiferous tubles from 2 to 8 weeks of age, and 2) the cycle phenomena of seminiferous epithelia at 14 weeks of age in Japanese quail. Total 80 birds were examined at a week interval from 2 to 8 weeks, and 14 weeks of age. The results were summarized as follows： 1) The body and testis weights showed most prominent increase during 4 to 5 weeks and 6 to 8 weeks of age respectively. And also the diameters of seminiferous tubles were abruptly enlaged during 6 to 8 weeks of age. 2) Genocytes in the seminiferous tubles were still in existence at 3 weeks of age, however they did not come out after 4 weeks of age. Spermatogonia, primary spermatocytes and spermatids made their first arpearances in the seminiferous from 3, 4 and 6 weeks of age, respectively. Spermatozoa were observed for the first time at 7 weeks of age, but full spermatogenic activity was completed from 8 weeks of age. 3) At 14 weeks of age, the average weight at testis was 3.7g and its ratio to the body weight was approximately 3.0 percent. And at this age, average diameter of seminiferous tubules was 192.08 $\mu\textrm{m}$, and average numbers of spermatogonia, spermatocytes, spermatids and spermatozoa within the cross section of seminiferous tubules were 7.74, 40.81, 28.42, 104.55 and 105.98, respectively. Spermatogonia and spermatid were classfied into 2 and 3 types, respectively. 4) At 14 weeks of age, the cycle of seminiferous epithelium could be divided into S stages with following characteristics. (1) Stage I： Seminiferous tubules showing type I and II spermatids. (2) Stage II： Seminiferous tubules showing type III spermatids only. (3) Stage III： Immature spermatozoa gathered near the sertoli cytoplasm. (4) Stage IV： Forming a bundle of 15-20 spematozoa. (5) Stage V： Spermatozoa bundle leaving the sertoli cytoplasm into lumen of the seminferous tubule. 5) Usually 2-3 stages of the seminiferous epithelium cycle were concurrently appeared within a tubular cross section, and frequency of each stage from I to V within cross section of seminiferous tubules were 11.91%, 27.03%, 27.96%, 19.04% and 17.98%, respectively.

• Journal of Technology Innovation
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• v.2 no.1
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• pp.1-57
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• 1994

본 고는 지속적 개발 론에 입각한 적극적인 에너지수요 관리정책을 추진한다는 전제하에 2001년과 2006년의 우리 나라 가정부문 전력수요를 전망하고자 한다. 본 고는 지속적 개발 시나리오를 추정함에 있어서 기존의 계량모형보다 일종의 공학적 모형인 공정분석(process analysis)을 선호한다. 계량모형이 주로 과거 수요의 소득 및 가격 탄성 치를 바탕으로 미래의 수요를 예측하는데 비하여 공정분석모형은 기술발전에 따른 미래의 효율변화(향상)를 비교적 잘 반영할 수 있기 때문이다. 본 고는 덴마크공과대학교 Norgard 교수팀이 개발한 모형을 도입하여 분석모형(수식 (6))을 전력수요 = 기기 수 $\times$ 전력서비스$\times$ 전력집약도와 같이 설정하고 이를 사용하여 냉장고, 텔레비전, 조명 기기, 난방기기 등과 같은 전력사용 기기 별로 2001년과 2006년이 전력수요를 전망하였다. 본 고는 전력수요를 전력사용 기기의 사용용량(300리터 용량의 냉장고 등)과 사용시간을 나타내는 전력서비스와 전력 서비스당 필요 전력사용량을 나타내는 전력집약도로 나누어 구분하고 있는 모형을 이용함으로써 소득향상효과와 함께 기술발전에 따른 효율개선효과를 분석할 수 있다. 1) 생활수준 향상에 따라 전력서비스는 지금과 같이 증가한다, 2) 현실적으로 가능한 범위 내에서 전력사용 기기에 대한 최저 에너지 효율 제를 실시한다, 3) 현재 사용중인 기기 들은 원칙적으로 수명이 다한 후 고효율 기기 들로 자연 교체한다, 4) 최저 에너지 효율 제를 제외한 다른 제도 및 정책개선, 사용자의 에너지소비형태 개선에 따른 절전 잠재 량을 고려하지 않는다 등의 가정 하에 전력수요를 추정한 결과 1992년에 796 GWh(100)이었던 우리 나라 가정부문 전력수요는 2001년과 2006년에 29,237 GWh(134)와 33,118 GWh(152)로 각각 34%와 52%증가할 것으로 나타났다. 이 경우 1992년부터 2006년까지 가정용 전력수요 증가율은 연평균 3%로 추정된다. 기기의 서비스(가구수$\times$기기의 보급 율$\times$기기의 전력서비스)가 소득향상에 따라 증가하는데도 불구하고 전력수요의 증가율이 GDP(같은 기간 동안 연평균 증가율 5.7%)보다 매우 낮은 것은 기기의 대형화와 기기의 보급을 증가에 따른 전력의 추가수요가 기기의 에너지효율 개선으로 대부분 상쇄될 것이기 때문이다. 향후 10년 내에 기기에 따라 전력사용량을 25%~50%정도까지 줄일 수 있을 것으로 분석된다. 기술발전에 따른 기기의 에너지효율 개선효과는 본 고의 2006년도 가정용 전력수요의 전망치 33,118 GWh가 기존방식에 의한 한전의 전망치 61,155 GWh의 54%수준밖에 되지 않는데 서도 잘 나타나고 있다. 한편 본 고는 경제성장과 환경보존을 동시에 달성할 수 있는 지속적 개발의 실천방안으로서 에너지 수요관리를 논하고자 한다. 고효율 기기의 개발과 조기도입을 촉진시키는 에너지 수요관리 통하여 우리는 에너지효율을 대폭 개선시키며 대기오염 배출량도 대폭 줄일 수 있다. 본 고는 에너지 공급관리(공급확충)위주에서 에너지 수요관리위주로서의 에너지정책 전환은 불가피하다고 판단한다. 에너지 공급시스템보다 에너지 수요시스템위주로 전체 에너지시스템을 획기적으로 개선시키기 위해서는 최저 에너지효율제의 광범위한 실시와 함께 고효율 기기의 개발과 보급에 필요한 유인책의 도입, 고효율 기기와 에너지의 효율적 이용에 대한 정보 등이 필요시 되고 있다. 우리 나라의 경우 현재의 산업구조와 기술수준을 고려하여 에너지 효율의 기준을 미국보다 다소 낮게 설정한다면 최저 에너지효율제의 도입이 문제가 되지 않을 것으로 판단된다. 본 고는 고효율 기기의 개발과 조기도입을 지원하기 위한 가칭 대기환경보존 및 에너지 수요관리기금의 창설을 제안한다. 전력부문의 경우 기금은 1. 탄소세, 2. 전력소비에 대한 수요 관리 세의 도입 혹은 3. 한국전력공사 전력판매수입의 일정 분으로 조성될 수 있을 것으로 본다. 예를 들어 선진국들이 탄소세를 예정대로 도입한다는 전제하에 우리 나라가 2000년을 기준으로 탄소 톤당 8달러(석유 배럴 당 85센트)의 탄소세를 도입한다면 연간 7억 2,000만 달러(약5,760억 원)규모의 기금을 조성할 수 있다. 이 중 연간 2,000억 원 정도를 고효율 기기의 개발과 조기도입에 지원한다면 우리 나라 에너지 시스템 효율은 대폭 개선될 수 있을 것으로 예상된다.

• Journal of the Mineralogical Society of Korea
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• v.19 no.1 s.47
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• pp.15-29
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• 2006

Synthetic Mn-tourmalines (tsilaisite) were obtained by hydrothermal synthesis under the condition of 2 Kbar, $375{\sim}700^{\circ}C$, and 50 day-run-time with complete substitution of Mg in dravite by Mn (Mn%=0, 25, 50, 75, and 100%). They are all 6 samples containing Mn-tourmaline with some amounts of albite, spessartine, rhodocrosite, phlogopite etc, showing different synthetic condition of temperature and Mn composition. Synthetic Mn-tourmalines are of site deficiency in X-site ($0.53{\sim}0.68$) more than that of natural ones (approx. $0.2{\sim}0.3$) and show Mn cations occupying Y-site less than expected with initial experiments, leading to failure in synthesis of end-member tsilaisite. Rietveld structural refinements reveal that $R_{wp}$ ($R_{p}/R_{exp}$) is in the range of 13.35 and 18.62%, $R_{B}$ and S (CofF) are $4.85{\sim}6.25%$ (S-18: 8.57%), $1.31{\sim}1.59$ (S-18: 1.81), respectively. Unit cell parameters (space group R3m, z=3) are ${\alpha}=15.8994\;{\AA}$ and $c=7.1846\;{\AA}$ in average (S-18: ${\alpha}=15.9491\;{\AA},\;c=7.1773\;{\AA}$). Average bond lengths of and are $2.67{\sim}2.69\;{\AA}$ (S-18: $2.65\;{\AA}$) and $2.00{\sim}2.02\;{\AA}$ (S-18: $1.96\;{\AA}$), respectively. Ditrigonality (${\delta}$) are in the range of 0.022 and 0.031 (S-18: 0.061), indicating degrading symmetry with increase of Mn content.

• Journal of Life Science
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• v.17 no.5 s.85
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• pp.634-640
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• 2007

Our previous study suggested that n-3 fatty acid deficiency was associated with significantly reduced spatial learning as assessed by Morris water maze test. Here we investigated an effect of n-3 fatty acid deficiency on rat brain, retina and serum fatty acyl compositions at 15 wks age using a first generational artificial rearing technique. Newborn Rat pups were separated on day 2 and assigned to two artificial rearing groups or a dam-reared control group. Pups were hand fed artificial milk via custom-designed nursing bottles containing either 0.02%(n-3 Deficient) or 3.1% (n-3 Adequate) of total fatty acids as a-linolenic acid(LNA). At day 21, rats were weaned to either n-3 deficient or n-3 adequate pelleted diets and fatty acid compositions of brain, retina and liver were analyzed at 15 wks age. Brain docosahexaenoic acid(DHA) was lower(58% and 61%, P<0.05) in n-3 deficient in comparison to n-3 adequate and dam-reared groups, receptively, while brain docosapentaenoic acid(DPAn-6) was increased in the n-3 deficient group. In retina and serum fatty acid compositions, the decreased precentage of DHA and increased precentage of DPAn-6 were observed. These results suggested that artificial rearing method can be used to produce n-3 fatty acid deficiency in the first generation and that adequate brain DHA levels are required for optimal brain function.

• Journal of Life Science
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• v.21 no.2
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• pp.183-193
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• 2011

Migration and differentiation of mesenchymal stem cells are crucial for tissue regeneration in response to injury. Sphingosine-1-phosphate (S1P) is a bioactive lipid that regulates a variety of biological processes, including proliferation, survival, differentiation and motility. In the present study, we determined the role of S1P in migration and differentiation of human bone marrow-derived mesenchymal stem cells (BMSCs). S1P stimulated migration of BMSCs in a dose- and time-dependent manner, and pre-incubation of the cells with pertussis toxin completely abrogated S1P-induced migration, suggesting involvement of Gi-coupled receptors in S1P-induced cell migration. S1P elicited elevation of intracellular concentration of $Ca^{2+}$ ($[Ca^{2+}]_i$) and pretreatment with VPC23019, an antagonist of $S1P_1/S1P_3$, blocked S1P-induced migration and increase of $[Ca^{2+}]_i$. Small interfering RNA-mediated knockdown of endogenous $S1P_1$ attenuated S1P-induced migration of BMSCs. Furthermore, S1P treatment induced expression of $\alpha$-smooth muscle actin ($\alpha$-SMA), a smooth muscle marker, and pretreatment with VPC23019 abrogated S1P-induced $\alpha$-SMA expression. S1P induced phosphorylation of p38 mitogen-activated protein kinase (MAPK), and pretreatment of cells with SB202190, an inhibitor of p38 MAPK, or adenoviral overexpression of a dominant-negative mutant of the p38 MAPK blocked S1P-induced cell migration and $\alpha$-SMA expression. Taken together, these results suggest that S1P stimulates migration and smooth muscle differentiation of BMSCs through an $S1P_1$-p38 MAPK-dependent mechanism.

• The Korean Journal of Nuclear Medicine
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• v.39 no.3
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• pp.200-208
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• 2005

Purpose: Tc-99m labeled diethylenetriaminepentaacctic acid (DTPA)-coupled galactosylated human serum albumin (GSA) is a currently used imaging agent for asialoglycoprotein receptor (ASGPR) of the liver, but, it has several shortcomings. Recently a new ASGPR imaging agent, $^{99m}Tc$-lactosylated human serum albumin (LSA), with simple labeling procedure, high labeling efficiency, high stability was developed. In order to assess the feasibility of the $^{99m}Tc$-LSA as a ASGPR imaging radiopharmaceuticals, we performed biodistribution study of the tracer in liver injured mice model and the results were compared with histolgic data. Materals and Methods: To induce hepatic damage in ICR mice, diethylnitrosamine (DEN) ($60mg/kg/week{\times}5time$, low dose or $180mg/kg/week{\times}2times$, high dose) and thioacetamide (TAA) ($50mg/kg{\times}1time$) were administrated intraperitoneally. Degree of liver damage was evaluated by tissue hematoxilin-eosin stain, and expression of asialoglycoprotein receptor (ASGPR) was assessed by immunohistochemistry using ASGPR antibody. $^{99m}Tc$-LSA was intravenously administrated via tail vein in DEN or TAA treated mice, and biodistribution study of the tracer was also performed. Results: DEN treated mice showed ballooning of hepatocyte and inflammatory cell infiltration in low dose group and severe hapatocyte necrosis in high dose group, and low dose group showed higher ASGPR staining than control mice in immunohistochemical staining. TAA treated mice showed severe hepatic necrosis. $^{99m}Tc$-LSA Biodistribution study showed that mice with hepatic necrosis induced by high dose DEN or TAA revealed higher blood activity and lower liver activity than control mice, due to slow clearance of the tracer by the liver. The degree of liver uptake was inversely correlated with the degree of histologic liver damage. But low dose DEN treated mice with mild hepatic injury showed normal blood clearance and hepatic activity, partly due to overexpression of ASGPR in mice with mild degree hepatic injury. Conclusion: Liver uptake of $^{99m}Tc$-LSA was inversely correlated with degree of histologic hepatic injury in DEN and TAA treated mice. These results support that $^{99m}Tc$-LSA can be used to evaluate the liver status in liver disease patients.

• The Korean Journal of Nuclear Medicine
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• v.33 no.4
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• pp.398-404
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• 1999

Purpose: Diabetic nephropathy is the most common cause of end stage renal disease and the incidence is progressively increasing. The aim of this study was to investigate the differences of $^{99m}Tc$-DMSA renal uptake among diabetic patients with normoalbuminuria, microalbuminuria and overt proteinuria, and then to determine the clinical usefulness of $^{99m}Tc$-DMSA in predicting early diabetic nephropathy Materials and Methods: $^{99m}Tc$-DMSA scan was performed and a total renal uptake of $^{99m}Tc$-DMSA was measured in 145 diabetic patients. Patients were divided into 3 groups according to the amount of 24 hour urinary albumin excretion as Group I (normoalbuminuria, 74 cases), Group II (microalbuminuria, 39 cases), and Group III (overt proteinuria, 32 cases). The differences of $^{99m}Tc$-DMSA renal uptake among the 3 groups and the correlation between the renal uptake of $^{99m}Tc$-DMSA and other clinical parameters were analyzed. Results: The total renal uptake of $^{99m}Tc$-DMSA of Group II ($40.8{\pm}11.0%$) was significantly lower than that of Group I ($54.4{\pm}6.3%$, p<0.001). The uptake of Group III ($27.7{\pm}12.0%$) was significantly lower than those of both Group I and Group II (p<0.001). $^{99m}Tc$-DMSA total renal uptakes correlated negatively with serum creatinine level (r=-0.629, p<0.001) and positively correlated with creatinine clearance rate (r=0.102, p<0.001). Conclusion: $^{99m}Tc$-DMSA total renal uptake of diabetic patients with microalbuminuria was significantly decreased compared with that of patients of normoalbuminuria. Therefore, $^{99m}Tc$-DMSA scan can be used as a diagnostic study for early detection of the diabetic nephropathy.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.4
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• pp.292-300
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• 2008

Purpose: Our purpose was to evaluate F-18 FDG uptake in pulmonary lymphangitic carcinomatosis (PLC) according to CT findings and histology of lung cancer. Materials and Methods: Thirty-three lung cancer patients with PLC were enrolled in this retrospective study. All the patients had a CT-based diagnosis of PLC. Chest CT findings of PLC were classified on the basis of involvement of axial interstitium. We categorized the involvement of axial interstitium as group 1, and the involvement of peripheral interstitium only as group 2. Visual and semiquantitative analyses by F-18 FDG PET/CT were performed in the PLC lesions. At first, we analyzed the F-18 FDG uptake in the PLC by visual assessment. If abnormal uptake was seen in the PLC, we drew regions of interest in the PLC lesions to obtain the maximum SUVs (maxSUVs). Results: Of the 33 patients, 22 had abnormal F-18 FDG uptake in the visual assessment. There was no significant difference in the frequency of abnormal F-18 FDG uptake between group 1 and group 2 (p=0.17), although the frequency of group 1 tended to be higher than group 2 (15/19 (78.9%) in group 1, 7/14 (50.0%) in group 2). However, group 1 had a higher maxSUV than group 2 (p<0.01, group 1: $2.9{\pm}1.4$, group 2: $1.5{\pm}0.6$). There was no significant difference in the frequency of abnormal F-18 FDG uptake and maxSUV among the histology of the lung cancers. Conclusion: The involvement of axial interstitium in the PLC by lung cancer has a higher maxSUV than the involvement of only peripheral interstitium.

• Korean Journal of Ecology and Environment
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• v.35 no.3 s.99
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• pp.198-212
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• 2002

A numerical variation and abnormalities were studied on egg bags and embryos of Korean salamander, Hynobius leechii from agricultural habitat. The teratogenic and toxic effects of fungicide benomyl were also investigated with early embryos from non-agricultural habitat. We collected 144 egg bags from agricultural region, and 3418 of early embryos were contained. The lengths of egg bags were varied from 10 to 23 cm and the most frequent length was 19 cm. The number of embryos was varied from 7 to 43, and the most frequent range was 22 to 26. Spontaneous abnormalities were occurred in 406 embryos among 116 egg bags, and 24 kinds of external abnormalities were found. Individuals showing severe external defect were histologically studied and they showed optic dyspalsia, thyroid carcinoma, somatic muscular dysplasia, partial biaxial structure, decrease of red blood cells in the heart, cephalic degeneration and intestinal dysplasia. 385 embryos from non-agricultural region were exposed to 200 nM${\sim}$ 1 ${\mu}$M of benomyl at blastula or gastrula for 12 days. All embryo were dead in the concentration of 1 ${\mu}$M (LD$_{100}$) and 75% of embryos were dead in 800nM of benomyl. Speciflc effect due to benomyl was acrania or cephalic dysplasia and this restult suggests that the benomyl inhibit stongly to the development of neural tissue. These abnormal developments may be caused by antimitotic action, inhibition of tubulin complex, destruction of microtubule, inhibitions of neurulation and closing of neural fold, and by the inhibition of the movement of neural crest cells.

• Korean Journal of Ecology and Environment
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• v.37 no.3 s.108
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• pp.344-354
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• 2004

A pilot study was performed from September 2000 to April 2004 to examine the feasibility of the wetland-pond system for the agricultural reuse of reclaimed water. The wetland system was a subsurface flow type, with a hydraulic residence time of 3.5 days, and the subsequent pond was 8 $m^3$ in volume (2 m ${\times}$ 2 m ${\times}$ 2 m) and operated with intermittent-discharge and continuous flow types. The wetland system was effective in treating the sewage; median removal efficiencies of $BOD_5$ and TSS were above 70.0%, with mean effluent concentrations of 27.1 and 16.8 mg $L^{-1}$, respectively, for these constituents. However, they did often exceed the effluent water quality standards of 20 mg $L^{-1}$. Removal of T-N and T-P was relatively less effective and mean effluent concentrations were approximately 103.2 and 7.2 mg $L^{-1}$, respectively. The wetland system demonstrated high removal rate (92 ${\sim}$ 90%) of microorganisms, but effluent concentrations were in the range of 300 ${\sim}$ 16,000 MPN 100 $mL^{-1}$ which is still high for agricultural reuse. The subsequent pond system provided further treatment of the wetland effluent, and especially additional microorganisms removal in addition to wetland-pond system could reduce the mean concentration to 1,000 MPN 100 $mL^{-1}$ from about $10^5$ MPN 100 $mL^{-1}$ of wetland influent. Other parameters in the pond system showed seasonal variation, and the upper layer of the pond water column became remarkably clear immediately after ice melt. Overall, the wetland system was found to be adequate for treating sewage with stable removal efficiency, and the subsequent pond was effective for further polishing. This study concerned agricultural reuse of reclaimed water using natural systems. Considering stable performance and effective removal of bacterial indicators as well as other water quality parameters, low maintenance, and cost-effectiveness, wetland- pond system was thought to be an effective and feasible alternative for agricultural reuse of reclaimed water in rural area.