Concurrent Relations of Commodity Futures

Namkoong,Hongseok,Kim, Woochang 대한산업공학회 2011 대한산업공학회 추계학술대회논문집 Vol.2011 No.11

Literatures have focused on the relationship between basis, cost of storage and convenience yield, as given by the Theory of Storage. However, the relations among futures contracts should be considered as a whole, upon discussion of futures-spot relationships: futures curve reflects inventory level and the risk premium and thus the dynamics of future spot price. Here the predictive ability of the futures curve over future spot price dynamics is empirically proven. When the futures curve is highly volatile, market participants’ expectation on inventory and risk premium vary. As this discrepancy widen, spot inventory is deemed unstable. Thus, spot price rises for a short time. But then, as inventory restores itself, spot mean reverts, making a sharp market correction. An investment strategy that predicts spot price crashes using the futures curve is devised. Equal weight portfolio of 26 commodities is used. Results corroborate the conjecture; it predicts major market crashes. Result indicates that contemporary relations among futures contracts are crucial in futures-spot relationships. This result expands the view offered by the Theory of Storage by highlighting the importance of relationship among futures contracts.

MoSi2 의 초음파에 관한 기초적 연구

김유철,남궁재관 한국산업안전학회 1994 한국안전학회지 Vol.9 No.1

Ultrasonic for MoSi₂/Y. C. Kim, C. K. Namkoong/MoSi₂ in the silicides has excellence in the oxidation and corrosion resistence. When the solid state bonding sintered-MoSi₂/metal or the thermal sprayed coating by powder-MoSi₂ on the metal are carried out, the defects may be occured at the bonded surface. So, the method for evaluating the existence of the defects by non-destructive inspection is strongly desired. Here, the characteristics of ultrasonic for sintered-MoSi₂ are elucidated and the possibility of the detection of defects using by ultrasonic is investigated.

GENETIC STUDIES OF KOREAN POPULATION : 24. GENETIC POLYMORPHISM OF APOLIPOPROTEIN A-Ⅳ AND APOLIPOPROTEIN E^1

NAMKOONG, YONG,KIM, YUNG JIN,LEE, CHUNG CHOO 충남대학교 기초과학연구소 1993 연구논문집 Vol.13 No.-

As a part of research for clarifying the genetic composition of Korean population, phenotypes and allele frequencies of Apo A-Ⅳ and Apo E in human plasma have been studied using polyacrylamide gel isoelectric focusing and immunoblotting techniques. Blood samples were obtained from healthy individuals living in Seoul. Kangnung and Cheju, Korea. Two phenotypes of Apo A-Ⅳ controlled by two alleles were appeared in Korean population. The calculated allele frequencies of Apo A-Ⅳ*1 and Apo A-Ⅳ*2 were 0.9851 and 0.0149, respectively. There were four phenotypes for Apo E in Korean population. On the basis of 3 alleles for Apo E, allele frequencies of Apo E*2, Apo E*3 and Apo E*4 were 0.0054, 0.8216, and 0.1730, respectively.

Immunomodulatory Effects of Fucoidan on NK Cells in Ovariectomized Rats

NamKoong, Seung,Kim, Ye-Jin,Kim, Tae-Seong,Sohn, Eun-Hwa The Plant Resources Society of Korea 2012 한국자원식물학회지 Vol.25 No.3

In this study we investigated the effects of supplementation with fucoidan from brown alga on the function of natural-killer (NK) cells to evaluate the possibility as an immunomodulator in ovariectomized (OVX) rats. A total of 18 female Wistar rats (six weeks) were used this study and 12 rats were OVX, and the rest of rats were sham-operated. The sham and one OVX group were fed standard diet, and the remaining OVX group received fucoidan (0.05% supplemented diet). After 12 weeks of supplementation, rats were sacrificed to assess the tumoricidal activity of the NK cells and the NO-iNOS regulation from splenocytes. The mass of body and the immune organs such as spleen and thymus were also studied. In OVX rats, body and thymus weights increased, however fucoidan supplementation did not change the body mass and organs weight compared to OVX group. Fucoidan supplementation increased NK cell activity and reduced NO-iNOS production in OVX rats. Ex vivo treatment of fucoidan increased NK cell activity in splenocytes from shame and OVX rats. Ex vivo, we confirmed that fucoidan partially reduced the NK cell activity in the presence of iNOS inhibitors in OVX-splenocytes. These results indicate fucoidan supplementation has a NK cell tumoricidal activity, which are regulated by the iNOS production in OVX rats. This suggests that fucoidan is useful for potential therapeutic strategies as a nutrient in regulating the NK cells in postmenopausal osteoporosis patients.

Chemically, spatially, and temporally resolved 2D mapping study for the role of grain interiors and grain boundaries of organic-inorganic lead halide perovskites

Namkoong, Gon,Jeong, Hyeon Jun,Mamun, Abdullah,Byun, Hyeryung,Demuth, Derek,Jeong, Mun Seok North-Holland 2016 Solar Energy Materials and Solar Cells Vol. No.

<P><B>Abstract</B></P> <P>Grain interiors (GIs) and grain boundaries (GBs) of perovskites have been investigated using chemically, spatially, and temporally resolved measurements. Two dimensional (2D) chemical mapping measurements revealed the GBs consisted of the non-stoichiometric PbI<SUB>x</SUB> or CH<SUB>3</SUB>NH<SUB>3</SUB>PbI<SUB>x</SUB>, that were characterized by an absence of chloride, an enriched oxygen concentration, and a high density of iodide vacancies. In addition, steady-state 2D photoluminescence showed the bandgap broadening at the GBs while 2D lifetime mapping measurement suggested that the GBs indeed contained deep defect centers. However, it is found that defective GBs in perovskite materials do not act as high recombination sites for photogenerated charge carriers due to the bandgap broadening of non-stoichiometric PbI<SUB>x</SUB> or CH<SUB>3</SUB>NH<SUB>3</SUB>PbI<SUB>x</SUB> perovskites at the GB that forms the potential barriers for photo-generated charge carriers toward the GBs. As a consequence, the photo-generated charge carriers adjacent to the GBs will be easily repelled by the GBs, resulting in a greater reduction of the recombination of photogenerated charge carriers. This is one possible reason for the high performance of CH<SUB>3</SUB>HN<SUB>3</SUB>PbI<SUB>3-x</SUB>Cl<SUB>x</SUB> based solar cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Grain interiors and grain boundaries of perovskites have been investigated. </LI> <LI> Bandgap broadening at the GBs was formed due to PbI<SUB>x</SUB> or CH<SUB>3</SUB>NH<SUB>3</SUB>PbI<SUB>x</SUB>. </LI> <LI> GBs were characterized by no chloride, enriched oxygen, and iodide vacancies. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Two-dimensional photoluminescence and time resolved lifetime contrasting the grain interiors and grain boundaries.</P> <P>[DISPLAY OMISSION]</P>

Voltage Control of Distribution Networks to Increase their Hosting Capacity in South Korea

NamKoong Won,Jung Won-Wook,Shin Chang-Hoon,Hwang Pyeong-Ik,Jang Gilsoo 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.3

This paper presents the results of a study of a voltage management technology called parameter determination of voltage regulator (PDVR) implemented in a 22.9 kV distribution network. Korea Electric Power Corporation has developed this PDVR technology for increasing the hosting capacity without causing any voltage problems in LV (220/380 V) networks. PDVR calculates and provides the operation settings of voltage regulators such as on load tap changer, pole mounted automatic voltage regulator, and distributed generation (DG). Subsequently, these settings are applied to the voltage regulators, which further optimize the 22.9 kV network voltage without the control of the distribution management system (DMS). A study of the operations and performance of PDVR through the analysis of test results is presented in this paper.

The integral membrane protein ITM2A, a transcriptional target of PKA-CREB, regulates autophagic flux via interaction with the vacuolar ATPase

Namkoong, Sim,Lee, Kang Il,Lee, Jin I,Park, Rackhyun,Lee, Eun-Ju,Jang, Ik-Soon,Park, Junsoo TaylorFrancis 2015 AUTOPHAGY Vol.11 No.5

<P>The PKA-CREB signaling pathway is involved in many cellular processes including autophagy. Recent studies demonstrated that PKA-CREB inhibits autophagy in yeast; however, the role of PKA-CREB signaling in mammalian cell autophagy has not been fully characterized. Here, we report that the integral membrane protein ITM2A expression is positively regulated by PKA-CREB signaling and ITM2A expression interferes with autophagic flux by interacting with vacuolar ATPase (v-ATPase). The <I>ITM2A</I> promoter contains a CRE element, and mutation at the CRE consensus site decreases the promoter activity. Forskolin treatment and PKA expression activate the <I>ITM2A</I> promoter confirming that ITM2A expression is dependent on the PKA-CREB pathway. ITM2A expression results in the accumulation of autophagosomes and interferes with autolysosome formation by blocking autophagic flux. We demonstrated that ITM2A physically interacts with v-ATPase and inhibits lysosomal function. These results support the notion that PKA-CREB signaling pathway regulates ITM2A expression, which negatively regulates autophagic flux by interfering with the function of v-ATPase.</P>

Enhanced Hypothalamic AMP-Activated Protein Kinase Activity Contributes to Hyperphagia in Diabetic Rats

Namkoong, C.,Kim, M. S.,Jang, P. G.,Han, S. M.,Park, H. S.,Koh, E. H.,Lee, W. J.,Kim, J. Y.,Park, I. S.,Park, J. Y.,Lee, K. U. American Diabetes Association 2005 Diabetes Vol.54 No.1

<P>AMP-activated protein kinase (AMPK) acts as a cellular energy sensor, being activated during states of low energy charge. Hypothalamic AMPK activity is altered by hormonal and metabolic signals and mediates the feeding response. To determine the effect of diabetes on hypothalamic AMPK activity, we assayed this activity in streptozotocin (STZ)-induced diabetic rats. Compared with control rats, STZ-induced diabetic rats had significant hyperphagia and weight loss. Hypothalamic AMPK phosphorylation and alpha2-AMPK activity were higher and acetyl-CoA carboxylase activity was lower in diabetic rats than in control rats. Chronic insulin treatment or suppression of hypothalamic AMPK activity completely prevented diabetes-induced changes in food intake as well as in hypothalamic AMPK activity and mRNA expression of neuropeptide Y and proopiomelanocortin. Plasma leptin and insulin levels were profoundly decreased in diabetic rats. Intracerebroventricular administration of leptin and insulin reduced hyperphagia and the enhanced hypothalamic AMPK activity in diabetic rats. These data suggest that leptin and insulin deficiencies in diabetes lead to increased hypothalamic AMPK activity, which contributes to the development of diabetic hyperphagia.</P>

Detection of c-K-ras Point Mutation in Ovarian Cancer

Namkoong, Sung Eun,Lee, Joon Mo,Kim, Jin Woo,Han, Sang Kyun,Kim, Heung Kee,Park, Jong Sup,Kim, Seung Jo CATHOLIC MEDICAL CENTER 1994 Bulletin of the Clinical Research Institute Vol.22 No.1

To detect the point mutation of c-k-ras in ovarian cancer, GGT of codon 12 was replaced by GAT, AGT, TGT and GTT, then we performed polymerase chain reaction and agarose gel electrophoresis and confirmed it using Southern blot hybrization with digoxygenin detection system. The frequency of c-k-ras point mutation was compared with the clinico-pathological characteristics of 37 ovarian cancer patients. The incidences of four-typed point mutations of K-ras oncogene in 37 ovarian cancers were 35.1%(13/37) and distribution were 32.4%(12/37), 2.7%(1/37), 0%(O/37) and 0%(O/37) in GGT to GAT, GGT to AGT, GGT to TGT, and GGT to GTT, respectively. The incidence of K-ras point mutations on codon 12 among 37 patients with ovarian cancer according to histological type was 35.5%(8/22) with serous cystadenocarcinomns, 28.6%(2/7) with mucinous cystadenocarcinomas. Comparing the positive rate of K-ras point mutations on code 12 among 37 patients with ovarian cancer in different clinical stages, point mutation was detected in 14.3%(1/7) with stage Ⅰ, 28.6%(2/7) with stage Ⅱ, and 43.5%(10/23) with stage Ⅲ/Ⅳ and there was statistically significant increasement of point mutations of K-ras oncogene with advance of the clinical stage of ovarian cancer (P<0.05). The incidence of K-ras point mutntions on codon 12 among 33 patients with ovarian cancer who were performed pelvic lymph node dissection was 52.4%(l1/21) of the patients with positive pelvic lymph node metastases and 16.7%(2/12) of the patients without pelvic lymph node metastasis and the difference was statistically significant (P<0.05). The activation of ras oncogene seems to be a major implication of the multistep process of ovarian carcinogenesis and tumor progression. Furthermore, the point mutation of c-K-ras gene could occur more frequently in the patients of ovarian cancer in far advance stage, and the those with pelvic lymph node metastases than in those without pelvic lymph node metastases, suggesting the role in tumor invasion and metastases.

The Effect of Picibanil on Cell-Immunity in Patients with Gynecological Malignant Tumor

Namkoong, Sung Eun,Lee, Joon Mo,Lee, Hun Young,Jung, Jae Keun,Kim, Seung Jo CATHOLIC MEDICAL CENTER 1986 Bulletin of the Clinical Research Institute Vol.14 No.1

Natural killer cell-mediated cytotoxicity(NKMC), total, helper and suppressor T-cells were measured before and 4 weeks after treatment with 0.5-3.0 KE of OK-432 in the patients with trophoblastic disease which were divided into 2 subgroups of low risk (n=10) and high risk (n=11), and compared with those in normal control group (n=9). In the group of low risk trophoblastic disease no change was noted in any of all parameters after treatment. However, in the group of high risk trophoblastic disease, NKMC as well as total and helper T-cells before treatment were significantly lower while suppressor T-cells were higher than those in normal control. And all above data before treatment were definitely reversed after treatment except NKMC that remained unchanged. Considering above results OK-432 may play an important role in host defense mechanism through lymphokine or humoral immune response by increasing the ratio of helper to suppressor T-cells rather than increasing NKMC.