• Journal of The Korean Astronomical Society
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• v.23 no.1
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• pp.1-13
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• 1990

New uvby photoelectric photometry was carried out for a $\delta$ Scuti variable, HR1170. By applying the Fourier method and the linear least square method, three frequencies were derived: $f_1=10.06134c/d$ ($P_1=0.^d0994$). $f_2=11.91754c/d$ ($P_2=0.^d0839$). $f_3=18.96776c/d$ ($P_3=0.^d0527$). From the observed pulsational constants and from the phase difference and amplitude ratios for color(b-y) and magnitude y. three different pulsation modes (n, l) of $f_1(0,0)$, $f_2(1,2)$, $f_3(3,2)$ are deduced, indicating the existence of nonradial mode in HR1170. Some physical parameters indicate that HR1170 is evolving at the stage of H-shell burning.

• Journal of the Korean Applied Science and Technology
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• v.7 no.1
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• pp.13-24
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• 1990

2-N,N,N-trimethyl ammonia decanoate, 2-N,N,N-trimethyl ammonio dodecanoate, 2-N,N,N-trimethyl ammonia tetradecanoate and 2-N,N,N-hexadecanoate with in straight long chain alkyl carboxybetaines, and N-decyl N,N-dimethyl ammonio ethanoate, N-dodecyl N,N-dimethyl ammonia ethanoate, N-tetradecyl N,N-dimethyl ammonia ethanoate and N-hexadecyl N,N-dimethyl ammonia ethanoate with in nitrogen-straight long chain alkyl carboxy betaines measured respectively surface tensions by the stalagmometer method at various temperature, also their critical micelle concentration were evaluated. In micellization, the contribution of standard free energy change(${\Delta}G^{\circ}m$), standard enthalpy change(${\Delta}H^{\circ}m$) and standard entropy change (${\Delta}S^{\circ}m$), have been calculated, with increasing temperature. ${\Delta}H^{\circ}m$ changes from negative, and a similar change in the sign of ${\Delta}H^{\circ}m$ is observed with increasing chain length at $25^{\circ}C$, while the entropy of micellization, ${\Delta}S^{\circ}m$ is positive over the temperature range studied, it becomes less so at higher temperatures. Estimates of the enthalpy and entropy contribution attributable to the ion head group and alkyl chain have been made. The enthalpy and entropy change, per methylene group increase respectively with increasing chain length the result are discussed in terms of current theories of micellization.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.4
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• pp.380-389
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• 2007

Stable carbon and nitrogen isotopes were analyzed in suspended particulate organic matter, macroalgae and macrobenthic invertebrates in order to determine the importance of primary organic matter sources in supporting food webs of rocky subtidal and intertidal macroalgal beds in the Korean coasts. Investigations were conducted at the inter tidal sites within Gwangyang bay, a semi-enclosed and eutrophicated bay, and the subtidal sites of the east coast, a relatively oligotrophic and open environment, in May and June 2005. Water-column suspension feeders showed more negative $\delta^{13}C$ values than those of the other feeding guilds, indicating trophic linkage with phytoplankton and thereby association with pelagic food chains. In contrast, animals of the other feeding guilds, including interface suspension feeders, herbivores, deposit feeders, omnivores and predators, displayed relatively less negative $\delta^{13}C$ values than those of the water-column suspension feeders and similar with that of macroalgae, indicating exclusive use of macroalgae-derived organic matter and association with benthic food chains. Most the macrobenthic species were considered to form strong trophic links with benthic food chains. In addition, the distribution of higher $\delta^{15}N$ values in macrobenthic consumers and macroalgae at the intertidal sites of Gwangyang Bay than those at the subtidal sites of the east coast suggests that anthropogenic nutrients may enhance the macroalgal production at the intertidal sites and in turn be incorporated into the particular littoral food web in Gwangyag Bay. These results confirm the dominant role of macroalgae in supporting rocky subtidal and intertidal food webs in the Korean coasts.

• Journal of the East Asian Society of Dietary Life
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• v.6 no.3
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• pp.317-323
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• 1996

Physicochemical characteristics of Cassia tora seeds roasted at different conditions were investigated. Intact Cassia tora seeds were composed of water 11.6% crude protein 13.1%, crude fat 4.4%, curde fiber 13.8%, N-free extract 47.2% and ash 4.9%. Stacking volume ratio was increased generally by swelling, but soluble solids were decreased by rosating process L and B values decreased conspicuously as roasting temperature increase, but $\Delta$E value increased. The content of anthraquinones was 1, 200mg% in unroasted Cassia tora seeds, it increased as roasting time and temperature increase and reached maxium amount at 19$0^{\circ}C$-30min, 21$0^{\circ}C$-20min. and 23$0^{\circ}C$-10min. agter that it decreased remarkably. Optimum roasting condition of Cassia tora seeds was 21$0^{\circ}C$-20min.

• Animal cells and systems
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• v.15 no.3
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• pp.235-241
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• 2011

To examine variation in trophic pathways and the characteristics of food webs from organic matters to aquatic insects, we used stable isotopes to study an intermittent stream system of the Inukami River, Japan. The aquatic insects, including Glossosoma spp., Chironominae spp., Stenelmis spp., Rhyacophilla nigrocephala, and Hexatoma spp., were characterized by different feeding strategies. The ${\delta}^{13}C$ values for these species indicated that Glossosoma spp. graze upon periphyton; Chironominae and Stenelmis spp. mainly feed on benthic particulate organic matter, and R. nigrocephala and Hexatoma spp., which were identified as predators, feed upon Glossosoma, Stenelmis, and/or Chironominae spp. This suggests that the trophic position of consumers at each station may be determined by the trophic position of basal food sources in situ. For trophic pathways, the ${\delta}^{13}C$ values for both organic matter and aquatic insects tended to gradually decrease, whilst the ${\delta}^{15}N$ values increased from the upper reach to the lower reaches, relative to the physicochemical and geographical conditions. These parameters indirectly influence the flow of energy from organic matter to consumers within food web in an intermittent stream system.

• Journal of Conservation Science
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• v.33 no.6
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• pp.533-539
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• 2017

Stable carbon and nitrogen isotope results recorded in human bone reflects palaeodiet, nutrition, subsistence and palaeoenvironment. We analyzed the remains of the Naju Yeongdong-ri people, who live at around $6^{th}$ century, excavated from stone chambers and stone-lined tombs. The following results of the analysis of stable carbon and nitrogen isotopes were obtained: ${\delta}^{13}C=-19.5{\pm}0.7$‰, ${\delta}^{15}N=9.6{\pm}0.7$‰, (n=9). The value for stable carbon isotopes indicates that the Naju Yeongdong-ri people had a largely $C_3$-based diet such as rice, barley, and beans. On the other hand, the value for stable nitrogen isotopes reflect the consumption of terrestrial animal protein. This study presents new information on the dietary patterns of the Naju Yeongdong-ri people, whose tombs were similar to the Baekje tomb style and their burial type was much like the one followed by the indigenous people of the Yeongsan river basin.

• Food Science of Animal Resources
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• v.33 no.1
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• pp.39-44
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• 2013

Origin authenticity of the animals used as food has always been a major concern to consumers around the world. In the past twenty years, a stable isotope ratio has been used for origin authentication. In this study, pork samples, both local and imported, were collected from the major markets from all around South Korea and analyzed for stable isotope ratios of nitrogen (${\delta}^{15}N$‰) and carbon (${\delta}^{13}C$‰), using Isotope Ratio Mass Spectrometry (IR-MS). A total of 599 samples with 335 Korean and 264 imported from 13 countries within America and Europe were investigated in accordance to the standard established methods for isotope ratio analysis. The results showed a significant variation related to the origin of the samples, explaining the difference in the feeding styles of the pork in each country. The stable isotope ratio values of carbon (${\delta}^{13}C$‰) were found in the decreasing order of: America ($-15.55{\pm}1.01$‰)>Korea ($-19.62{\pm}0.89$‰)>Europe ($-24.79{\pm}1.35$‰). Canada was having ${\delta}^{13}C$ ratio of $-22.87{\pm}0.92$‰, which is very low in the region of America and very close to Europe (-23.78 to -27.17‰). For nitrogen ${\delta}^{15}N$‰ the order was: America ($4.92{\pm}0.71$‰)>Europe ($4.54{\pm}0.66$‰)>Korea ($3.69{\pm}0.54$‰), with a slight variation among countries in each region studied. From the results it was concluded that the stable isotope ratio of the pork samples from different countries provide enough information about the origin and is therefore a potential tool which can be employed for origin authentication.

• Journal of Ginseng Research
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• v.42 no.4
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• pp.485-495
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• 2018

Background: The geographical origin of Panax ginseng Meyer, a valuable medicinal plant, is important to both ginseng producers and consumers in the context of economic profit and human health benefits. We, therefore, aimed to discriminate between the cultivation regions of ginseng using the stable isotope ratios of C, N, O, and S, which are abundant bioelements in living organisms. Methods: Six Korean ginseng cultivars (3-yr-old roots) were collected from five different regions in Korea. The C, N, O, and S stable isotope ratios in ginseng roots were measured by isotope ratio mass spectrometry, and then these isotope ratio profiles were statistically analyzed using chemometrics. Results: The various isotope ratios found in P. ginseng roots were significantly influenced by region, cultivar, and the interactions between these two factors ($p{\leq}0.001$). The variation in ${\delta}^{15}N$ and ${\delta}^{13}C$ in ginseng roots was significant for discriminating between different ginseng cultivation regions, and ${\delta}^{18}O$ and ${\delta}^{34}S$ were also affected by both altitude and proximity to coastal areas. Chemometric model results tested in this study provided discrimination between the majority of different cultivation regions. Based on the external validation, this chemometric model also showed good model performance ($R^2=0.853$ and $Q^2=0.738$). Conclusion: Our case study elucidates the variation of C, N, O, and S stable isotope ratios in ginseng root depending on cultivation region. Hence, the analysis of stable isotope ratios is a suitable tool for discrimination between the regional origins of ginseng samples from Korea, with potential application to other countries.

• Journal of the Korean Chemical Society
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• v.33 no.2
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• pp.156-163
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• 1989

The $ν_a+amide II$ combination band of thiopropionamide has been recorded for investigation of Hydrogen bonding between thiopropionamide (TPA) and N,N-dimethylalkylamide (DMF, DMA and DMP) in carbon tetrachloride over the range of $5^{\circ}$ to $55^{\circ}$. The combination band of monomeric TPA and hydrogen-bonded TPA can be resolved by Lorentzian-Gaussian product function into monomeric TPA and hydrogen-bonded TPA with amides. The association constants ($K_1$) for the hydrogen-bonded TPA were calculated by the concentrations of the monomeric TPA and the hydrogen-bonded TPA obtained from the computer resolved absorption bands. Thermodynamic parameters for the Hydrogen bonding have been evaluated by the analysis of the temperature dependent spectra. The ${\Delta}$$H^{\circ}$ of hydrogen-bonded TPA with DMF, DMA and DMP have been found to be-12.5, -13.5 and -14.1 kJ/mol, respectively. The corresponding ${\Delta}$$S^{\circ}$for the above system were -15.2, -17.9 and -22.3 J/mol${\cdot}$deg, respectively.

• Animal cells and systems
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• v.16 no.2
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• pp.162-171
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• 2012

We investigated food webs of a $Salix$ $subfragilis$-dominated wetland in the Janghang wetland in the Hangang estuary, which is very close to the Demilitarized Zone, along the west coast of Korea. Our study focused on understanding sesarmine crab ($Sesarma$ $dehaani$)-related food webs in a $S.$ $subfragilis$ forest. For our study, we used carbon and nitrogen stable isotopes and fatty acid biomarkers. We collected samples of plants, animals, and detrital sediment from four quadrats ($5{\times}5m^2$) set in the $S.$ $subfragilis$ community. Samples were collected from September 2006 to June 2009, except during the winter hibernation period of $S.$ $dehaani$. In the wet season, the sediment showed relatively high ${\delta}^{13}C$ and low ${\delta}^{15}N$ signatures compared with relatively low ${\delta}13C$ and high ${\delta}15N$ signatures in the dry season. Mature $S.$ $dehaani$ appeared to feed on fresh leaves and other carbon sources, such as immature individuals or fish, in addition to detrital sediment, which appeared to be the main carbon source for immature crabs. Principal component analysis of fatty acid biomarkers of $S.$ $dehaani$ showed a clear difference between immature individuals (10-30 mm) and mature ones (larger than 30 mm), indicating that the main food source for immature crabs was detrital sediment, whereas mature crabs foraged plants in addition to consuming detrital sediment. On the basis of our results from stable isotope and fatty acid analyses, mature $S.$ $dehaani$ appeared to feed on detrital sediment and fresh leaves of $S.$ $subfragilis$ in summer in addition to engaging in cannibalism of immature individuals.