• Journal of the Korean Magnetic Resonance Society
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• v.23 no.4
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• pp.93-97
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• 2019

Black ginger (Kaempferia parviflora) is a short-lived ginger plant with dark purple colored root and is known to be effective in treating diabetes and obesity. To find out the difference in the characteristics of the black ginger according to the variety of production, 1D proton NMR experiments were performed on 4 types of black gingers from different regions. The NMR spectra of all black ginger showed the characteristic peaks of the polymethoxy flavone compounds, and the chemical shifts and intensity of peaks showed slight differences depending of the type of black ginger implying the difference in molecular environment. These initial NMR experiments can be applied to the identification of the diversity of black ginger in physiological function according to the climate of regions using SNIF-NMR (Site-specific Natural Isotope Fractionation studied by NMR).

• Ocean Science Journal
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• v.40 no.3
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• pp.167-176
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• 2005

A time-series sediment trap was deployed at 1,034 m water depth in the eastern Bransfield Strait for a complete year from December 25, 1998 to December 24, 1999. About 99% of total mass flux was trapped during an austral summer, showing distinct seasonal variation. Biogenic particles (biogenic opal, particulate organic carbon, and calcium carbonate) account for about two thirds of annual total mass flux $(49.2\;g\;m^{-2})$, among which biogenic opal flux is the most dominant (42% of the total flux). A positive relationship (except January) between biogenic opal and total organic carbon fluxes suggests that these two variables were coupled, due to the surface-water production (mainly diatoms). The relatively low $\delta^{13}C$ values of settling particles result from effects on C-fixation processes at low temperature and the high $CO_2$ availability to phytoplankton. The correspondingly low $\delta^{l5}N$ values are due to intense and steady input of nitrates into surface waters, reflecting an unlikely nitrate isotope fractionation by degree of surface-water production. The $\delta^{l5}N$ and $\delta^{l3}C$ values of sinking particles increased from the beginning to the end of a presumed phytoplankton bloom, except for anomalous $\delta^{l5}N$ values. Krill and the zooplankton fecal pellets, the most important carriers of sinking particles, may have contributed gradually to the increasing $\delta^{l3}C$ values towards the unproductive period through the biomodification of the $\delta^{l3}C$ values in the food web, respiring preferentially and selectively $^{12}C$ atoms. Correspondingly, the increasing $\delta^{l5}N$ values in the intermediate-water trap are likely associated with a switch in source from diatom aggregates to some remains of zooplankton, because organic matter dominated by diatom may be more liable and prone to remineralization, leading to greater isotopic alteration. In particular, the tendency for abnormally high $\delta^{l5}N$ values in February seems to be enigmatic. A specific species dominancy during the production may be suggested as a possible and speculative reason.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.4
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• pp.284-291
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• 2001

To study whether N isotope composition (${\delta}^{15}N$) of crop reflects the kind of fertilizer (chemical or organic) applied to field, a pot experiment was conducted. Corn (Zea mays L.) was cultivated under greenhouse conditions for 70 days. Composted pig manure and urea were applied at 0 and 0 (C0U0), at 0 and 300 (COU2), at 300 and 0 (C2U0) and at 150 and $150kg\;N\;ha^{-1}$ (C1U1), respectively. The ${\delta}^{15}N$ values of composted pig manure and urea were + 13.9‰ and -2.3‰, respectively. The ${\delta}^{15}N$ values of whole parts (roots + stems + leaves + grains) were + 12.7, + 12.9, + 14.0 and + 13.0‰ for C0U0, C0U2, C2U0 and C1U1 treatments, and were not significantly affected by the application of isotopically different N sources (P<0.05). However, leaves or grains showed significantly (P<0.05) different ${\delta}^{15}N$ values between treatments. The ${\delta}^{15}N$ values of leaves and grains were + 14.3 and + 16.2‰ for C2U0, +13.2 and +13.9‰ for C0U0, +10.1 and + 12.6‰ for C1U1 and +10.1 and +12.4‰ for C0U2 treatments. The different ${\delta}^{15}N$ values of corn from the values of N sources (compost and urea) applied to soil showed that the ${\delta}^{15}N$ values of corn were affected not only by the isotope composition of N source, but also by N pool mixing and isotope fractionation accompanying N transformation. This study suggests that although the ${\delta}^{15}N$ values of crop are not identical to the ${\delta}^{15}N$ values of N sources applied to fields, the application of isotopically different N sources such as compost and chemical fertilizer may result in qualitative difference in ${\delta}^{15}N$ values of crop.

• Economic and Environmental Geology
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• v.36 no.6
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• pp.441-455
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• 2003

The most common water types are found to be Ca-$HCO_3$, Ca-Na-$HCO_3$ and Ca-Na-$HCO_3$-Cl in Gwangju groundwater. Groundwater near the Gwangju stream are characterized Ca-Cl water type, with over 50 mg/L of C1- and 400 ${\mu}$S/cm of EC. The systematic variation of $Cl^-$, $HCO_3^-$,- EC and ${\gamma}^{18}O$ values in groundwater with distance away from drainages is caused by streamwater infiltration. Stable isotope data indicate that ${\gamma}$D and ${\gamma}^{18}O$ values of groundwaters near drainages were enriched by evaporation effect, showing a equation of ${\gamma}$D=7. 1${\times}{\gamma}^{18}O$-1. ${\gamma}^{18}O$ values over -6${\textperthansand}$ are anomalous in the unconfined groundwater zones, which are influenced by the local surface water enriched in $^{18}O$ composition. Groundwater in highland shows remarkably light ${\gamma}^{18}O$ values below -8$\textperthousand$. The infiltration of streamwater is dominant in unconfined alluvium aquifer near drainages. ${\gamma}^{13}$CDIC values (-17.6∼-15.2$\textperthousand$) of groundwaters near drainages revealed that dissolved inorganic carbon (DIC) is predominantly originated from natural soil-derived $CO_2$. ${\gamma}^{15}N$ and ${\gamma}^{18}O$ values of nitrate are 0∼17.0${\textperthansand}$ and 6.6∼17.4${\textperthansand}$, respectively. Relationship between ${\gamma}^{15}N$ and ${\gamma}^{18}O$ shows a systematic isotopic fractionation caused by denitrification of 40∼60%, suggesting that the major source of groundwater nitrate originated from nitrate of soils, and mixing nitrate of soil and sewage or manure.