Peripheral Serotonin: a New Player in Systemic Energy Homeostasis

Namkung, Jun,Kim, Hail,Park, Sangkyu Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.12

Whole body energy balance is achieved through the coordinated regulation of energy intake and energy expenditure in various tissues including liver, muscle and adipose tissues. A positive energy imbalance by excessive energy intake or insufficient energy expenditure results in obesity and related metabolic diseases. Although there have been many obesity treatment trials aimed at the reduction of energy intake, these strategies have achieved only limited success because of their associated adverse effects. An ancient neurotransmitter, serotonin is among those traditional pharmacological targets for anti-obesity treatment because it exhibits strong anorectic effect in the brain. However, recent studies suggest the new functions of peripheral serotonin in energy homeostasis ranging from the endocrine regulation by gut-derived serotonin to the autocrine/paracrine regulation by adipocyte-derived serotonin. Here, we discuss the role of serotonin in the regulation of energy homeostasis and introduce peripheral serotonin as a possible target for anti-obesity treatment.

Blending effect of sewage sludge and woody biomass into coal on combustion and ash agglomeration behavior

Namkung, Hueon,Lee, Young-Joo,Park, Ju-Hyoung,Song, Gyu-Seob,Choi, Jong Won,Choi, Young-Chan,Park, Se-Joon,Kim, Joeng-Geun Elsevier 2018 Fuel Vol.225 No.-

<P><B>Abstract</B></P> <P>The co-combustion of sewage sludge and woody biomass is a key issue in coal power plants. Different combustion and ash behaviors of sewage sludge and woody biomass cause unpredictable operating concerns. In this study, the combustion and ash agglomeration behavior of blended fuel of sewage sludge and woody biomass (BSW) were investigated while coal co-combusted with it. Thermogravimetric analysis (TGA) revealed that adding a high amount of BSW into the coal lowered volatilization, ignition, and burn-out temperature. The char combustion reactivity of coal differed from that of BSW. The shrinking core model (SCM) and volumetric reaction model (VRM) were used to fit the char combustion reactivity of coal and BSW. In the case of ash agglomeration behavior, BSW addition led to increasing particle agglomeration at fouling temperatures. In particular, phosphorus composition influenced particle growth, which was verified using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDX) analysis. Furthermore, the ash mixture ratio of BSW and coal changed the intensity of the phosphorus-bearing mineral phase from X-ray diffraction (XRD) analysis, and finally influenced the melting temperature of the ash.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The combustion and ash agglomeration characteristics of coal and BSW mixture were investigated. </LI> <LI> Addition of BSW into the coal lowered the combustion temperature profiles during non-isothermal heating conditions. </LI> <LI> Carbon and reagent gas reaction occurred on exterior and interior of the particle during char combustion. </LI> <LI> BSW containing high phosphorus contents made a high agglomeration tendency and low melting mineral phase. </LI> </UL> </P>

Characteristics of novel synthetic fuels using coal and sewage sludge impregnated bioliquid applying for a coal combustion system

Namkung, Hueon,Park, Ju-Hyoung,Lee, Young-Joo,Song, Gyu-Seob,Choi, Jong Won,Kim, Joeng-Geun,Park, Jun-Su,Um, Byung Hwan,Song, Kwang Ho,Park, Se-Joon,Choi, Young-Chan Elsevier 2017 Fuel processing technology Vol.167 No.-

<P><B>Abstract</B></P> <P>The application of biomass resources and sewage sludge is currently the most important issue in the field of coal combustion systems. The main drawback for operating a boiler system is its varied firing characteristics and low heating value. In this study, we have developed new synthetic fuels, namely hybrid sludge fuel (HSF), using coal and sewage sludge impregnated bioliquid (molasses) and evaluated their properties by comparison with conventional fuels. To prepare the HSF, it was treated in a carbonization system at 250°C. Depending on the van Krevelen diagram, the fuel quality of HSF was superior to that of raw bioliquid and sewage sludge. In addition, its fuel characteristic was similar to sub-bituminous and bituminous coal. Thermogravimetric analysis (TGA) indicated only a single-stage combustion pattern for HSF during non-isothermal heating. To clarify the unburned carbon (UBC) content, an ultimate analysis was conducted. The amount of UBC of the HSF was much more than that of sewage sludge, but less than that of coal. To investigate the surface hydrophobicity of HSF, Fourier transform infrared spectroscopy (FT-IR) analysis and a moisture re-adsorption test were carried out. The HSF possessed high hydrophobicity and presented a low moisture re-adsorption rate compared to conventional fuels.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The new synthetic fuel (HSF) using coal and sewage sludge impregnated bioliquid was investigated. </LI> <LI> HSF properties were similar to sub-bituminous and bituminous coal on the van Krevelen diagram. </LI> <LI> HSF showed single-stage combustion characteristics from the thermogravimetric analysis. </LI> <LI> HSF presented higher fuel reactivity in comparison with low reactivity coal. </LI> <LI> HSF had a higher hydrophobicity on the surface. </LI> </UL> </P>

Regulation and Expression of α-Glycerol-3-phosphate Dehydrogenase(GPDH)in Drosophila melanogaster

Namkung, Yong,Kim, Se Jae,Lee, Chung Choo,Kim, Kyungjin 濟州大學校 基礎科學硏究所 1991 基礎科學硏究 Vol.4 No.1

노랑초파리의 α-glycerol-3-phosphate dehydrogenase(GPDH)의 발생단계 및 조직특이적 발현에 대한 발생유전학적 조절 양상을 연구하였다. 노랑초파리의 GPDH는 주로 흉부와 복부에서 각각 활성을 보이는 GPDH-1과 GPDH-3 의 두가지 동위효소로 이루어져 있는데, 성충에서 총 GPDH활성의 62%는 흉부에서 나타내며 복부에서는 총 GPDH활성의 약 32%를 보였다. 그러나 두 조직에서 GPDH의 상대적인 합성량은 서로 비슷하며 GPDH-3가 GPDH-1보다 훨씬 빨리 turnover됨을 암시하였다. 순수분리한 GPDH-1 으로 항혈청을 만든 후 두 동위효소의 면역학적인 동질성을 조사한 결과, 두 효소의 구조적인 차이는 매우 근소하였다. GPDH 동위효소의 기원을 규명하기 위해서 유충과 성체 조직으로 immunoblotting 과 in vitro translation을 수행한 바, 단백질 수준에서 GPDH-1의 단일체는 GPDH-3 의 단일체보다 분자량이 다소 큰 것으로 나타났다. 그러나 유충과 성체에서 추출한 RNA로 합성한 translation산물을 분석한 결과, 분자량이 동일한 하나의 band만 검출되는 것으로 보아 GPDH-3 는 GPDH-1에서 post translational modification 에 의해 생성되는 것으로 사료되었다. Several parameters of α-glycerol-3-pholphate dehydrogenase(GPDH)such as activity, content and translatable mRNA levels were measured to elucidate mechanism underlying developmental and tissue specific regulation of GPDH activity in Drosophila melanogaster. In adult segments, most of total GPDH activity(62%)was detected in thorax where GPDH-1 resided, while 32% of total GPDH activity was only detected in abdomen where GPDH-3 resided. The relative synthesis of GPDH was, however, similar in both tissues, although 58% of total GPDH was synthesis in abdomen. These results strongly suggest that the turnover rate of the abdominal enzyme(GPDH-3)was much more rapid than that of thoracic enzymes(GPDH-1). In vitro translation and immunoblotting experiments also indicate that GPDH-3 was arised by posttranslational modification from a single polypeptide(GPDH-1)

Prediction of coal fouling using an alternative index under the gasification condition

Namkung, H.,Xu, L.H.,Kang, T.J.,Kim, D.S.,Kwon, H.B.,Kim, H.T. Applied Science Publishers 2013 APPLIED ENERGY Vol.102 No.-

Coal gasification was carried out in order to verify the coal fouling tendency in the drop tube furnace (DTF), which can simulate an entrained-bed gasifier. Thirteen pulverized coal samples, in the range of bituminous and sub-bituminous, were utilized, and compared, with predictions using a wide range of empirical indices. Large discrepancies were noted in most cases, with respect to experimental results, ash deposition rates, and different indices. Some indices used for anticipating fouling tendency are not co-related with the results of this experiment. A newly approached index, which is especially important considering the diffusivity parameter, looks at the ratio of acid and alkali mineral matters injected into gasifier and heat flux, indicates that traditional expressions are modified to account for other parameters which influence the ash deposition phenomenon. The alternative index resulted in improved correlations between predictions and experimental observations.

A New Species of Galloisiana (Grylloblattidae) from Kosudong-gul Cave in Korea

Namkung, Joon 한국곤충학회 1974 Korean journal of entomology Vol.4 No.2

한국의 동굴에서 Galloisiana가 종종 발견되지만 그 성숙한 자웅을 얻기는 힘든다. 저자는 1973年 겨울 남한강상류인 충북 단양군 고수동굴에서 성숙한 1♂, 1♀을 얻었다. 이는 지난번 발표한 Galloisiana biryongensis 전혀 다른 신종으로 밝혀졌으므로 이에 기재발표한다. 본종의 중요표징은 다음과 같다. (1) 몸길이 약 22mm의 중형종으로 뚜렷한 겹눈을 가지며 더듬이는 46-47마디이고, 그 셋째마디는 둘째마디의 약 3배의 길이이다. (3) 앞가슴판의 목피부판(The first cervical sclerite) 윗쪽 가에 4재적의 센털이 정열한다. (3) ♂의 제10배등판끝인 Supra-annal plate는 좌측이 일그러진 삼각형 꼴로 그 끝이 순하고 안쪽으로 굽어 있다. (4) 수생식기관의 바른쪽 원밑마디 (coxopodite)의 밑부끝에 투명한 단추꼴 돌기가 있으나 숨겨져 있어 외관상 잘 보이지 않는다. (5) 반전상 (Eveersible sac)은 작으며 음경의 양 모퉁이가 뿔꼴로 돌출하고 옆에는 갈구리꼴의 가시돌기가 있다. (6) 산란관의 상란관 끝은 미모의 제4마디의 $\frac{3}{4}$에 이르며, 그 밑부로부터 2/15 되는곳에 중란관의 밑부가 있다.

A New Species of Cave Dwelling Grylloblattoidea (Grylloblattidae) from Korea

Namkung, Joon 한국곤충학회 1974 Korean journal of entomology Vol.4 No.1

원시무시곤충으로 주목되고 있는 Grylloblattoidea는 1914년 E.M. Walker가 최초로 발표한 이래, 북미각지에서 7종.2아종, 일본에서 5종, Siberia에서 1종이 기재된 바 있으나 우리나라에서는 아직껏 밝혀진 바가 없다. 저자는 1966년 6월 보한강상류인 정선군 비룡동굴에서 완전한 1성웅을 채집한 바 있어 여기에 Gallcisiana biryongensis(비룡갈르와 벌레)로 명명 기재한다. 본종은 다양색.무안.체장 34mm로 기지의 어느 것보다도 대형종이다. 대체적구조는 일본산 Galloisiana nipponensis에 닮으나 제10복배판 끝 Supra-anal plate가 둔만년필촉과 같이 무듸게 되며, 북미종과는 부절욕반이 있음에서 외관상으로도 분명히 구별된다. 본종의 중요 표징은 다음과 같다. (1) 두부는 편본하고 폭이 약간 넓은 원형으로 두개선이 명료하고, 복안은 퇴화되었으나 강대한 안부강모가 나있다. (2) 전흉배는 저대한 정방형, 중흉배는 전변이 좁은 제형, 후흉배는 전변이 약천 좁은 제형으로 각 측연과 중앙부에 불규칙한 강모가 나있다. (3) 복배판은 제4, 5절이 최대이며, 각 절의 하변에 8개, 측연에 1개씩의 강모가 정열하며 제10배판 끝은 순한 만년필촉 꼴로 일견 2분 된 듯한 감을 준다. (4) 미모는 9절로 되며, 각 말단부에 3,4재의 장강모가 나 있고, 미세 투명한 긴 감각모가 보인다. (5) 보각은 완장하며 부절욕반이 명료하다. (6) 웅생식기관은 복잡한 구조를 갖추며, 복지는 좌우비대칭으로 좌지는 폭광인 ?꼴이고, 우지는 장삼각형으로 기부끝에 투명한 단추꼴 돌기가 보인다. (7) 대형의 주름진 반전낭이 우음경엽부에서 돌출하고 있으며, 비교적 완장한 주음경과 부음경이 보인다.

Effect of mineral components on sintering of ash particles at low temperature fouling conditions

Namkung, H.,Xu, L.H.,Kim, C.H.,Yuan, X.,Kang, T.J.,Kim, H.T. Elsevier Scientific Pub. Co 2016 Fuel processing technology Vol.141 No.1

The ash deposition phenomenon in the coal gasification process is a severe problem for continuous operation. The ash deposition rate is influenced by the behavior of ash particles on the deposit target. Dropped coal ash particles, which exhibit different behaviors on the deposit surface such as attachment, rebounding, and removal, were observed through the view port of a drop tube furnace (DTF). The different behaviors may be influenced by the state of the ash particles such as the sintering phenomenon, which is a function of the mineral content. To verify the mineral components important in sintering among the ash particles, transformation of the particle shape of synthetic ash reacted at 900<SUP>o</SUP>C was analyzed through a scanning electron microscope (SEM). The Fe, Ca, and Mg components were the main factors for sintering and agglomeration. The Fe, Ca, and Mg components sintered with Si and Al were observed in the mineral mapping of deposited coal ash by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) analysis. Sintering characteristics of coal ash were analyzed by the dilatometer technique. Sintering temperature, shrinkage, and sintering activation energy (E<SUB>sin</SUB>) were all found to be related to the Fe, Ca, and Mg contents.

One New Species of the Genus Galloisiana (Notoptera: Grylloblattidae) from Korea

Namkung, Joon(南宮焌) 한국동물분류학회 1986 Animal Systematics, Evolution and Diversity Vol.2 No.2

Primary Productivity of Phytoplankton at the Eutrophic down Reach of a Regulated River (the Han River, Korea)

Namkung, Hyun,Hwang, Gil Son,Kim, Bom Chul,Kim, Kap Soo 한국육수학회 2001 생태와 환경 Vol.34 No.4

수도권의 중심부를 가로지르는 한강의 하류수역은 조수의 영향을 받을 수 있는 하구의 상단부에 위치해 있다. 한강 하류수역은 한강 종합개발사업의 일환으로 이루어진 준설과 수중보 건설에 의해서 강물이 정체되었으며, 또한 지천으로부터 유입되는 많은 오염물질에 의해서 식물플랑크톤의 대량 발생을 촉진할 수 있는 환경으로 변화되었다. 본 연구에서는 부영양한 한강 하류수역에서 식물플랑크톤의 1차생산을 측정하였으며, 더불어 내부생성유기물과 외부기원유기물을 산정하였다. 1차생산력은 C-14 uptake법과 P-I 모델법으로 측정하였다. 1차생산력의 범위는 140∼4,890 mgC m^-2 day^-1(중앙값 1,865 mgC m^-2 day^-1)이었으며, 국내의 부영양한 호수와 유사한 수준이었다. 식물플랑크톤의 생물량 변동은 봄철에 최대치를 보였으며, 유량의 변화와 관련이 있는 것으로 나타났다. 외부기원유기물은 여름철 홍수기를 제외한 연중 내내 지천을 통하여 유입되는 오염물질에 의해서 좌우되었다. 총 유기물 부하량에 대하여 식물플랑크톤의 1차생산이 차지하는 기여도는 40.9%로서, 유수 생태계로서는 높은 수준이었다. The downstream reach of the Han River adjoining Seoul in Korea was the upper boundary of an estuary where tidal effect on the flow rate could be exerted. According to the comprehensive river regulation project, the river was channelized and impounded by two overflow dams, which provided favorable condition for algal growth in this sewage polluted eutrophic reach. In this study primary productivity of phytoplankton was measured in the down reach and the autochthonous and allochthonous organic carbon loadings were estimated. Primary production of phytoplankton measured by C-14 uptake and P-I model method ranged from 140 to 4,890 mgC m^-2 d^-1 (median value 1,865 mgC m^-2 d^-1) showing the level of eutrophic lakes. Phytoplankton density that varied according to water flow rate was highest in spring. Allochthonous organic carbon loading was dominated by sewage input through tributaries in most of days except flood flow period. The average proportion of autochthonous carbon generation by phytoplankton was 40.9%, which is very high proportion for a lotic habitat.