• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.197-197
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• 2010

음식물쓰레기의 삼성분은 수분, 휘발분, 회분이며 이들이 차지하는 비율은 계절, 지역별로 다소 상이하지만 수분 약 80%, 회분3%, 휘발분 17%이다. 음식물쓰레기 전처리과정으로 이물질제거, 탈수공정이 있으며 탈수공정에서 다량의 탈리액이 발생한다. 본 연구에서는 탈리액을 데칸타를 이용하여 1차로 원심분리하여 고.액 분리한 액을 실험대상으로 하였다. 실험대상 탈리액의 물성은 BOD 78,800[mg/l], COD 41,000[mg/l], 부유물질 25,900[mg/l], 총질소 928[mg/l]이었다. 탈리액에는 기름성분(육류, 식용유등), 입자상물질등이 포함되어 있으며 이들은 난분해성 유기물질로, 이를 제거하는데 기존의 처리방법으로 많은 어려움이 있어 주요한 수질오염 발생원이 되고 있다. 예를들면 하수처리장 폭기조 수면에 유막을 형성하여 산소공급을 방해함으로 미생물번식을 방해하는 요인이 된다. 본 연구는 음식물쓰레기 탈리액의 수분, 고형분, 유분으로의 삼상분리에 관한 것이다. 유분은 에멀젼형태로 안정되게 수층에 분산되어 존재한다. 미세기포를 이용한 부상법의 경우 미세기포 표면과 유분의 화학적친화력이 낮아 기포표면에 유분이 잘 부착되지 않으며, 원심분리 방법만으로는 유분 분리효율이 낮고, 추출에 의한 분리시 추출액이 다량 소요되고 처리시간이 길며 추출액 비용이 많이 소요된다. 탈리액을 유분, 슬러지, 수분으로 분리하면 환경오염을 일으키는 주요성분을 신재생에너지 원료로 활용할 수 있다. 유분의 주성분이 동식물성 유지이므로 전처리시 산촉매를 이용 수분과 유리지방산을 제거하고 염기성촉매를 이용하여 전이에스테르화 반응을 거치면 바이오디젤인 FAME과 글리세롤으로 변환하므로 글리세롤을 분리하면 바이오디젤을 얻을 수 있다. 슬러지는 입자상 물질로 착화가 잘 되고 건조하면 발열량이 높으며 중금속등에 오염되지 않아 청정연료로 활용이 가능하다. 실험실에서의 탈리액 삼상분리방법은 다음과 같다. 탈리액 30ml당 추출액으로 노말헥산을 1ml를 가한 다음 플라스크에서 $80^{\circ}C$로 가열 후 방냉한다. 가열중 노말헥산의 손실을 방지하기 위하여 증발가스를 콘덴서에서 응축하여 플라스크로 재순환한다. 탈리액을 플라스크에서 꺼내어 원심분리기 rack에 300-400g씩 병에 각각 넣고 4,000rpm으로 30분간 운전한다. 탈리액은 상부로부터 유분층, 미세입자층, 수층, 슬러지층으로 분리된다. 각 층의 계면에서 2종의 성분이 약간 섞일 수 있다. 유분을 분리한 후 유분층 잔존물과 미세입자층, 수층 상층부의 혼합물을 취하여 50g씩 병에 넣고 3,500rpm으로 10분간 운전한 후 유분을 분리한다. 마지막으로 미세입자층만을 3,500rpm으로 10분간 원심분리한 후 유분을 따로 분리한다. 얻어진 유분은 rotary evaporator에서 $120^{\circ}C$로 가열하여 유분과 노말헥산을 분리하며 분리효율을 제고하기 위하여 감압하에서 운전한다. 분리된 유분의 고위발열량이 9,450[Kcal/kg]이었으며 원소분석 결과 탄소 74.7%, 수소 12.55%, 질소 0.08%, 유황분 0.0003%이었다. 분리된 유분의 양은 계절별로 시료별로 다르며 가을철에는 1.6-1.9%, 여름철은 1.0-1.3%이었다. 분리된 슬러지로부터 Hg, As, Cr, Cd, Pb 중금속 성분이 검출되지 않았으며 수분 2.8%, 휘발분 76.85%, 회분 7.52%, 고정탄소 12.83%이었고 원소분석결과 탄소 45.25%, 수소 7.46%, 질소 5.05%, 산소 34.39%, 유황분 0.33%이었으며 저위발열량은 4,480[Kcal/kg]이었다. 분리된 슬러지 양은 11-19% 이었다.

• Journal of Embryo Transfer
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• v.31 no.3
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• pp.169-177
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• 2016

There is a growing interest in the application of primary hepatocytes for treatment of liver diseases in humans and for drug development. Several studies have focused on long-term survival and di-differentiation blocking of primary hepatocytes in an in vitro culture system. Therefore, the present study also aimed to optimize an in vitro culture system using primary rat hepatocytes. Primary rat hepatocytes from 6-week-old male Crl:CD rats were isolated using a modified two-step collagenase perfusion. Healthy $3.5{\times}10^6$ primary rat hepatocytes were seeded into a 2 dimensional (2D) culture in a 25T culture flask coated with collagen type I or into a 3D culture in a 125-ml spinner flask for 7 days. Production of plasma protein (ALB and TF), apoptosis (BAX and BCL2), and CYP (CYP3A1) related genes were compared between the 2D and 3D culture systems. The 3D culture system had an advantage over the 2D system because of the relatively high expression of ALB and low expression of BAX in the 3D system. However, the level of CYP3A1 did not improve in the 3D culture with and without the presence of a dexamethasone inducer. Therefore, 3D culture has an advantage for albumin production and primary rat hepatocyte survivability, but a low expression of CYP3A1 indicated that primary rat hepatocytes require a high-density culture for stress reduction by continuous flow.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.77-77
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• 2003

Coculture of HSC with bone marrow-derived mesenchymal stem cells (BM-MSCs) is one of used methods to increase cell numbers before transplant to the patients. However, because of difficulties to purify HSCs after coculture with BM-MSCs, it needs to develop a method to overcome the problem. In the present study, we have examined whether a culture insert placed over a feeder layer might support the expansion of HSCs within the insert. $CD34^+/ $ cells isolated from the umbilical cord blood by using midiMACS were divided into three groups. A group of 1 $\times$ $10^5$ cells were grown on a culture insert without feeder layer (Direct). The same number of HSCs was directly cocultured with BM-MSCs (Contact). The third group was placed onto an insert below which BM-MSCs were grown (Insert). To distinguish feeder cells from HSCs, BM-MSCs was pre-labeled fluorescently with PKH26 and 1 $\times$ $10^5$ cells were seeded in the culture dishes. After culture for 13 days, the expansion factor (x) of HSCs that were grown without feeder layer (Direct) was $26.6 \pm 8.4.$ In contrast, the number of HSCs directly cocultured with feeder layer was 59.6 $\pm$ 0.5 and that of HSCs cultured onto an insert was $46.9 \pm 8.4.$ The percentage of BM-MSCs cells remained being fluorescent was $97.9 \pm 0.3%$ after culture. Immune-phenotypically large proportion of cultured cells were founded to be differentiated into myeloid/monocyte progenitor cells. The ability of BM-MSCs, fetal lung, cartilage and brain tissue cells to support ex vivo expansion of HSCs was also examined using the insert. After 11 days of coculture with each of these cells, the expansion factor of HSCs was 15.0, 39.0, 32.0 and 24.0, respectively. Based upon these observations, it is concluded that the coculture method using insert is very effective to support ex vivo expansion of HSCs and to eliminate the contamination of other cells used to coculture wth HSCs.

• IMMUNE NETWORK
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• v.14 no.1
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• pp.21-29
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• 2014

Follicular helper T ($T_{FH}$) cells are recently highlighted as their crucial role for humoral immunity to infection as well as their abnormal control to induce autoimmune disease. During an infection, na$\ddot{i}$ve T cells are differentiating into $T_{FH}$ cells which mediate memory B cells and long-lived plasma cells in germinal center (GC). $T_{FH}$ cells are characterized by their expression of master regulator, Bcl-6, and chemokine receptor, CXCR5, which are essential for the migration of T cells into the B cell follicle. Within the follicle, crosstalk occurs between B cells and $T_{FH}$ cells, leading to class switch recombination and affinity maturation. Various signaling molecules, including cytokines, surface molecules, and transcription factors are involved in $T_{FH}$ cell differentiation. IL-6 and IL-21 cytokine-mediated STAT signaling pathways, including STAT1 and STAT3, are crucial for inducing Bcl-6 expression and $T_{FH}$ cell differentiation. $T_{FH}$ cells express important surface molecules such as ICOS, PD-1, IL-21, BTLA, SAP and CD40L for mediating the interaction between T and B cells. Recently, two types of microRNA (miRNA) were found to be involved in the regulation of $T_{FH}$ cells. The miR-17-92 cluster induces Bcl-6 and $T_{FH}$ cell differentiation, whereas miR-10a negatively regulates Bcl-6 expression in T cells. In addition, follicular regulatory T ($T_{FR}$) cells are studied as thymus-derived $CXCR5^+PD-1^+Foxp3^+\;T_{reg}$ cells that play a significant role in limiting the GC response. Regulation of $T_{FH}$ cell differentiation and the GC reaction via miRNA and $T_{FR}$ cells could be important regulatory mechanisms for maintaining immune tolerance and preventing autoimmune diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Here, we review recent studies on the various factors that affect $T_{FH}$ cell differentiation, and the role of $T_{FH}$ cells in autoimmune diseases.

• Journal of Environmental Science International
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• v.20 no.5
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• pp.565-574
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• 2011

This study analyzed the concentration of the heavy metals(Cd, Hg, iAs) of urine(n=576) from May, 2007 to Oct 2007. The subject was residents in G, Y, H industrial area, Jeollanam-do, in which exposure due to the adjacency of the industrial complex. As to the heavy metal concentration in the urine of the residents in the whole exposed region and the comparing region, the content of cadmium, mercury, and inorganic arsenic in the exposed region group were 1.23, 1.85, and 8.80 ${\mu}g$/g_ct respectively, and those of the comparing region group were 1.87, 2.00, and 8.93 ${\mu}g$/g_ct respectively, which indicates that the concentration of the comparing group was higher than that of the exposed group. The heavy metal concentration for each age group increased in proportion to age except those under 10 for some substances(p<0.01). As to geometric mean concentration cadmium and inorganic arsenic in urine according to the smoking history of the subject, the concentration of the smoking group and the non-smoking group were 1.65 ${\mu}g$/g_ct and 9.13 ${\mu}g$/g_ct respectively, while those of the non-smoking group were 1.47 ${\mu}g$/g_ct and 8.91 ${\mu}g$/g_ct respectively, which indicates that the former is higher than the latter. As to the inorganic arsenic concentration in urine according to the food preference, in order of vegetable, fish, and meat showed high concentration (p<0.01). To clarify the factors affecting the heavy metal concentration in urine among the subjects, the multiple regression analysis was conducted. As a result, it turned out that as to cadmium content in urine, gender, age, drinking, and smoking have influence on the subjects, with explanatory adequacy of 37.5 %.

• Korean Journal of Community Nutrition
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• v.12 no.4
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• pp.405-416
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• 2007

This study was to examine the needs among elementary school dietitians (n = 115) for developing a nutrition information internet site for children. A survey questionnaire included general characteristics, internet use regarding health and nutrition information, and needs for developing a nutrition information site. The mean age of the subjects was 36.2 years. The higher working experience group (> 10 years of working as dieticians) had higher mean age (p < 0.001), had a larger number of enrolled students at school (p < 0.01) and the number of those receiving school lunch (p < 0.01) than the counterparts (${\le}10$ years group). Sources of health and nutrition information were mainly PC/internet (60.4%) and seminar (14.4%). About 95% used health or nutrition information using the internet, however, the majority of users (71.6%) used internet information only when they needed it. Major reasons for using internet information was 'to get nutrition education materials' (63.8%) and 'to obtain general nutrition information' (21%). One third of the subjects were satisfied with nutrition information internet sites; major problems with internet sites were 'lack of content' (38.9%) and 'lack of practical information' (33%). These characteristics regarding internet use were not different between work experience groups. Major problems with nutrition education were 'lack of nutrition educational materials' (41.1 %) and 'lack of nutrition education skills' (32.1%). These were significantly different between the work experience groups (p < 0.01). Subjects preferred CD/internet to leaflet/booklet as nutrition educational materials. In developing nutrition sites for children, subjects wanted topics such as obesity assessment, dietary assessment, and obesity. Subjects responded that contents of nutrition information should be 'suitable to the children's knowledge levels' (31.1%), 'interesting enough by including quizzes, games and songs' (27.8%), 'inserting many illustrations/icons' (16.3%). In terms of designing internet sites for children, they wanted that internet sites should 'be easy enough to find the sites' (29.2%), 'use illustrations and characters' (24.8%), 'use communication channels such as Q&A' (18.7%). Needs for developing internet sites for children were not different by the work experience group. This study suggests that web sites for children should be carefully developed considering the contents and design, have less information with more illustrations, designed to induce the interest of children, as well as including sections such as eating habit assessment and games.

• Journal of Food Hygiene and Safety
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• v.26 no.3
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• pp.266-272
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• 2011

The safety of liquid-type herbal preparations (47 samples) and beverages containing herbal medicines (18 samples), which are distributed in Gyeonggi province was studied by analyzing heavy metals, benzo(a)pyrene, preservatives and sugar content and to explain the differences between medicine and food based on the labeling standards. The herbal preparation is regarded as medicine and can be differentiated from the beverages containing herbal medicine, which is food, based on the fact that the herbal preparation should be labeled with usage, dosage, efficiency and effect. The mean concentrations of Pb, As, Cd, Hg were found to be 0.014 mg/kg, 0.113 mg/kg, 0.004 mg/kg and 0.003 mg/kg in herbal preparation and 0.009 mg/kg, 0.122 mg/kg, 0.003 mg/kg and 0.002 mg/kg in beverages containing herbal medicines, respectively. In 10 cases of herbal preparations and 6 cases of beverages containing Rehmanniae Radix Preparata (Sukjihwang), benzo(a)pyrene was not found. According to preservative test on herbal medicine, dehydroacetic acid was found less than the indicated content in 6 cases out of 37 cases, which labeled with preservatives, and benzoic acid, dehydroacetic acid and methylparaben were contained with 164.0~198.0 mg/kg, 149.8~272.5 mg/kg and 88.4 mg/kg, respectively, in 3 cases out of 10 cases, which was not labeled with preservatives. Among 16 cases of beverages containing herbal medicines, 3 cases of preservative-labeled beverages had the preservatives, and the rest of all, which was not labeled with preservatives, did not show that they contain any preservative, therefore, it was suitable for the labeling standards. As a result of sugar content test, preservative-labeled products were not appreciably different from the others.

• The Korean Journal of Physiology
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• v.28 no.2
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• pp.215-224
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• 1994

The presence of a calcium current $(i_{Ca^{2+}})$ passed via a specific channel was examined in the unfertilized hamster egg using the whole-cell voltage clamp technique. Pure inward current was isolated using a $Ca^{2+}-rich$ pipette solution containing 10 mM TEA. This current was independent of external $Na^+$ and was highly sensitive to the $Ca^{2+}$ concentration in the bathing solution, indicating that the inward current is carried by $Ca^{2+}$. The maximal amplitude was $-4.12{\pm}0.58nA\;(n=12)$ with 10mM $Ca^{2+}$ at -3OmV from a holding potential of -8OmV. This current reached its maximum within 20ms beyond -3OmV and decayed rapidly with an inactivation time constant $({\tau})$ of 15ms. Activation and inactivation of this $i_{Ca^{2+}}$ was steeply dependent on the membrane potential. The $i_{Ca^{2+}}$ began to activate at the lower voltage of -55 mV and reached its peak at -35 mV, being completely inactivated at potentials more positive than -40 mV. These result suggest that $i_{Ca^{2+}}$ in hamster eggs passes through channels with electrical properties similar to low voltage-activated T-type channels. Other results from the present study support this suggestion; First, the inhibitory effect of $Ni^{2+}\;(IC_{50}=13.7\;{\mu}M)$ was more potent than $Cd^{2+}\;(IC_{50}=123\;{\mu}M)$. Second, $Ba^{2+}$ conductance was equal to or below that of $Ca^{2+}$. Third, $i_{Ca^{2+}}$ in hamster eggs was relatively insensitive to nifedipine $(IC_{50}=96.6\;{\mu}M)$, known to be a specific t-type blocker. The physiological role of $i_{Ca^{2+}}$ in the unfertilized hamster eggs remains unclear. Analysis from steady-state inactivation activation curves reveals that only a small amount of this current will pass in the voltage range $(-70{\sim}-30\;mV)$ which partially overlaps with the resting membrane potential. This current has the property that it can be easily activated by a weak depolarization, thus it may trigger a certain kind of a intracellular event following fertilization which may cause oscillations in the membrane potential.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.3
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• pp.274-279
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• 1985

Proximate compositions, minerals and protein fractions of the roots of cultured and wild Codonopsis lanceolata of different age groups were examined as the basic research for the study of their source of processed foods. The most abundant proximate composition of the roots of C. lanceolata was observed to be total sugars and next come crude protein, crude fiber, crude fat and ash in descending order irrespective of cultured and wild ones. The richest mineral contained in the roots was noticed to be K and followed by Mg and Ca. Generally increased tendency of crude protein, fat, ash, K, Mg, Ca, Mn, Zn, Cu and P contents were observed with older roots, however, decreased total sugars and Fe content. Lead and cadmium content was far bellow the authorized tolerance limits. The quantitative fractionation of the protein of the roots ranked albumin the highest content, followed by globuin, prolamin and glutelin. Decreased albumin content was observed with the older age roots, while increased globulin, prolamin and glutelin content. The minimum solubility of the soluble protein of the roots was found to be at pH 4.0 and maximum, at pH 10.0. Disc gel electrophoresis of the soluble protein of C. lanceolata roots showed almost similar patterns and numbers of bands. The molecular weight for main band protein was estimated to be about 90,000.

• Ocean Systems Engineering
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• v.1 no.4
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• pp.285-296
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• 2011

Spar platforms have several advantages for deploying wind turbines in offshore for depth beyond 120 m. The merit of spar platform is large range of topside payloads, favourable motions compared to other floating structures and minimum hull/deck interface. The main objective of this paper is to present the response analysis of the slack moored spar platform supporting 5MW wind turbine with bottom keel plates in regular and random waves, studied experimentally and numerically. A 1:100 scale model of the spar with sparD, sparCD and sparSD configuration was studied in the wave basin ($30{\times}30{\times}3m$) in Ocean engineering department in IIT Madras. In present study the effect of wind loading, blade dynamics and control, and tower elasticity are not considered. This paper presents the details of the studies carried out on a 16 m diameter and 100 m long spar buoy supporting a 90 m tall 5 MW wind turbine with 3600 kN weight of Nacelle and Rotor and 3500 kN weight of tower. The weight of the ballast and the draft of the spar are adjusted in such a way to keep the centre of gravity below the centre of buoyancy. The mooring lines are divided into four groups, each of which has four lines. The studies were carried out in regular and random waves. The operational significant wave height of 2.5 m and 10 s wave period and survival significant wave height of 6 m and 18 s wave period in 300 m water depth are considered. The wind speed corresponding to the operational wave height is about 22 knots and this wind speed is considered to be operating wind speed for turbines. The heave and surge accelerations at the top of spar platform were measured and are used for calculating the response. The geometric modeling of spar was carried out using Multisurf and this was directly exported to WAMIT for subsequent hydrodynamic and mooring system analysis. The numerical results were compared with experimental results and the comparison was found to be good. Parametric study was carried out to find out the effect of shape, size and spacing of keel plate and from the results obtained from present work ,it is recommended to use circular keel plate instead of square plate.