• Journal of Animal Science and Technology
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• v.59 no.6
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• pp.14.1-14.9
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• 2017

Background: Garlic and its constituents are reported to have been effective in reducing methane emission and also influence glucose metabolism in body; however, studies in ruminants using garlic leaves are scarce. Garlic leaves contain similar compounds as garlic bulbs, but are discarded in field after garlic bulb harvest. We speculate that feeding garlic leaves might show similar effect as garlic constituents in sheep and could be potential animal feed supplement. Thus, we examined the effect of freeze dried garlic leaves (FDGL) on rumen fermentation, methane emission, plasma glucose kinetics and nitrogen utilization in sheep. Methods: Six sheep were fed Control diet (mixed hay and concentrate (60:40)) or FDGL diet (Control diet supplemented with FDGL at 2.5 g/kg $BW^{0.75}$ of sheep) using a crossover design. Methane gas emission was measured using open-circuit respiratory chamber. Plasma glucose turnover rate was measured using isotope dilution technique of [$U-^{13}C$]glucose. Rumen fluid, feces and urine were collected to measure rumen fermentation characteristics and nitrogen utilization. Result: No significant difference in rumen fermentation parameters was noticed except for rumen ammonia tended to be higher (0.05 < P < 0.1) in FDGL diet. Methane emission per kg dry matter ingested and methane emission per kg dry matter digested were lower (P < 0.05) in FDGL diet. Plasma glucose concentration was similar between diets and plasma glucose turnover rate tended to be higher in FDGL diet (0.05 < P < 0.1). Nitrogen retention was higher (P < 0.05) and microbial nitrogen supply tended to be higher (0.05 < P < 0.1) in FDGL diet. Conclusion: FDGL diet did not impair rumen fermentation, improved nitrogen retention; while absence of significant results in reduction of methane emission, glucose turnover rate and microbial nitrogen supply, further studies at higher dose would be necessary to conclude the merit of FDGL as supplement in ruminant feedstuff.

• 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.

• YAKHAK HOEJI
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• v.38 no.6
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• pp.673-676
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• 1994

The each nitrogen site of ifosfamide metabolite isophosphoramide mustard was synthesized with isotope enriched nitrogen. $Gylcine-^{15}N$ was converted to $2-chloroethylamine-^{15}N$ hydrochloride which was then reacted with phenyl dichlorophosphate to provide $N,N'-bis(2-chloroethyl)phosphordiamidic-^{15}N_2$ acid phenylester(50%, $PhO(O)^{15}N(CH_2CH_2Cl_2)$. Catalytic hydrogenation of this phenyl ester followed by the addition of cyclohexylamine (CHA) provided $IPM-^{15}N$ as the CHA salt(70%).

• Applied Biological Chemistry
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• v.37 no.4
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• pp.277-286
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• 1994

The pot experiment using $^{15}N$ isotope dilution technique was carried out to calculate the balance of nitrogen of surface applied urea in the rice-soil system. The $^{15}N$ concentration was determined by stable isotope ratio mass spcetrometer (model: VG ISO-GAS MM622). In the pots with $^{15}N$ labeled urea application at the rates of 15 and 30 kg N/10a, the percentage of nitrogen derived from fertilizer (NDFF) in rice was higher at the rate of 30 kg N/10a (average 89%) than at the rate of 15 kg N/10a (average 64%). However, the recovery as percentage of fertilizer N by rice was higher at the rate of 15 kg N/10a (65.5%) than at the rate of 30 kg N/10a (54.2%). The percentage of the fertilizer N remained in extractable inorganic N form at the rates of 15 and 30 kg N/10a were $13.5%\;(NH_4-N\;5.53%,\;NO_3-N\;7.99%)$ and $16.5%\;(NH_4-N\;7.49%,\;NO_3-N\;8.98%)$ in unplanted soil, and $2.0%\;(NH_4-N\;0.63%,\;NO_3-N\;1.32%)$ and$2.3%\;(NH_4-N\;0.87%,\;NO_3-N\;1.40%)$ in soil planted to rice, respectively. The dominant form of inorganic-N in soil after harvest was $NO_3-N$ form rather than $NH_4-N$ form regardless of urea application rate or rice cultivation. The percentage of the fertilizer N remained in organic N form at the rates of 15 and 30 kg N/10a were 65.0 and 41.8% in unplanted soil, and 23.7 and 26.9% in soil planted to rice, respectively. In conclusion, the efficiency of surface-applied urea was greater at the rate 15 kg N/10a than at the rate of 30 kg N/10a.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.358-365
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• 2019

We measured the body composition, including bone mineral density (BMD) and food resource availability using dual energy X-ray absorptiometry and the carbon and nitrogen stable isotope ratios of body condition of 4 anuran species(Hyla japonica, Glandirana rugosa, Pelophylax nigromaculatus, Lithobates catesbeianus) in South Korea. Additionally, the carbon and nitrogen stable isotope ratios were employed to determine the food resource availability of anurans. We figured out the relationship between the body composition, including BMDs and food resource availability. The body composition and BMDs did not differ between male and female while there was difference among the species. Food resource availability and BMDs were the highest in L. catesbeianus, the lowest in H. japonica. BMDs tended to increase with higher food resource availability. Body composition and BMDs, which represent the body condition of an individual, can be used as an ecological indicator to assess the stability of the habitat of anurans.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.5
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• pp.493-505
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• 2020

Food web structures in the lower trophic levels of the seas around the Korean peninsula were investigated in August 2019 using stable isotopes. There were variable ratios of the carbon (-26.18 ~ -20.61 ‰) and nitrogen stable (5.36 ~ 15.20 ‰) isotopes in the particulate organic matter (POM). Most of the organisms ingested micro-POM as a major food source, but this varied spatially. The chaetognaths (3.40 ± 0.61) occupied the highest trophic level. The isotope mixing model showed that the proportions (13 ~ 51 %) of some organisms (i.e., copepods and euphausiids) reflected the relative contributions as major food sources for chaetognaths at each site.

• Korean Journal of Ecology and Environment
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• v.45 no.2
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• pp.242-251
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• 2012

To investigate foodweb of aquatic ecosystem in the Tamjin River, carbon and nitrogen stable isotopes ratios of aquatic organisms, as well as environmental indicators based on the water, were determined in this study. Various organisms such as fishes (Coreoperca kawamebari, Zacco platypus, Cobitis lutheri, and Pungtungia herzi) and periphyton (epilithon and epiphyte), and particulate- and coarse particulate organic matters (POM and CPOM) were collected in upper (Tamjin River, Yuchi Stream, and Omcheon Stream) and lower (TJ-1~TJ-5) reaches of Jangheung Dam. The nitrate concentration and ${\delta}^{15}N$ signature of POM and organisms (invertebrates and fish) were found to be more enriched toward the downstream section of the river. It was determined that allochthonous matter occurring from a tributary alters the chemical character of water, as well as the isotopic signature of organisms contained therein. Attached algae (ephilithon) were identified as a base component of the benthic foodchain further downstream.

• Korean Journal of Materials Research
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• v.29 no.5
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• pp.336-341
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• 2019

The gas adsorption isotherm requires accurate measurement for the analysis of porous materials and is used as an index of surface area, pore distribution, and adsorption amount of gas. Basically, adsorption isotherms of porous materials are measured conventionally at 77K and 87K using liquid nitrogen and liquid argon. The cold volume calibration in this conventional method is done simply by splitting a sample cell into two zones (cold and warm volumes) by controlling the level sensor in a Dewar filled with liquid nitrogen or argon. As a result, BET measurement for textural properties is mainly limited to liquefied gases (i.e. $N_2$ or Ar) at atmospheric pressure. In order to independently investigate other gases (e.g. hydrogen isotopes) at cryogenic temperature, a novel temperature control system in the sample cell is required, and consequently cold volume calibration at various temperatures becomes more important. In this study, a cryocooler system is installed in a commercially available BET device to control the sample cell temperature, and the automated cold volume calibration method of temperature variation is introduced. This developed calibration method presents a reliable and reproducible method of cryogenic measurement for hydrogen isotope separation in porous materials, and also provides large flexibility for evaluating various other gases at various temperature.

• Economic and Environmental Geology
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• v.42 no.6
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• pp.575-589
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• 2009

Groundwater has been extracted for irrigation in Sacheon-Hadong area, which is close to the South Sea. We analyzed chemical components of groundwater to examine the effects of seawater intrusion and agricultural activities in the study area. Most groundwater samples displayed the Na/Cl concentration ratios similar to that of seawater (0.55) with an increasing tendency of electrical conductivity ($227-7,910\;{\mu}S/cm$) towards the coast. In addition, statistical interpretation of the cumulative frequency curves of Cl and $HCO_3$ showed that 30.1% of the groundwater samples were highly affected by seawater intrusion. Groundwaters in the study area mostly belonged to the Ca-Cl and Na-Cl type, demonstrating that they were highly influenced by seawater intrusion and cation exchange. The result of oxygen-hydrogen isotope analysis demonstrated slightly higher $\delta^{18}O$ ((-8.53)-(-6.13)‰) and ${\delta}D$ ((-58.7)-(-43.7)‰) comparing to mean oxygen-hydrogen isotope ratios in Korea. As a result of nitrogen isotope analysis, the $\delta^{15}N-NO_3$ values ((-0.5)-(19.1)‰) indicate two major sources of nitrate pollution (organic nitrogen in soil and animal and human wastes) and mixed source of the two. However, denitrification may partly contribute as a source of nitrogen. According to factor analysis, four factors were identified among which factor 1 with an eigenvalue of 6.21 reflected the influence of seawater intrusion. Cluster analysis indicated the classification of groundwater into fresh, saline, and mixed ones.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.3
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• pp.318-331
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• 1996

Large and small seeds (44 and 22 mg per caryopsis) of a spring wheat (cv. Kulin) and a spring barley (cv. Skiff) were sown at two nitrogen rates (equivalent to 10 and 32 g m$^{-2}$ ) in well-watered pots under outdoor conditions to determine the effects of seed size and nitrogen (N) nutrition on water use efficiency (WUE) and carbon isotope discrimination ($\Delta$) and to evaluate interaction among $\Delta$, WUE and N nutrition in wheat and barley. Barley produced, on average, 105% more biomass (root＋shoot dry weight) than wheat at stem elongation because of early vigor. By anthesis this difference had disappeared as wheat had 16% more biomass than barley which headed 3 days earlier. Compared to plants grown from small seed, plants grown from large seed had much greater biomass in wheat than in barley at stem elongation and anthesis. Higher N nutrition increased average biomass of wheat and barley by 40 and 31%, respectively, at anthesis. Barley had 35 and 20% greater WUE (biomass gained/transpiration) than wheat at stem elongation and anthesis, respectively, and 2.0 to 3.6% lower $\Delta$ in aboveground shoots depending on growth stages and plant parts than wheat which had a greater stomatal conductance than barley. Seed size had a variable effect on WUE and did not affected $\Delta$ values. Water use efficiency was not affected by N rate at stem elongation in wheat and barley whereas WUE was increased 2 and 7%, respectively, in wheat and barley at anthesis with increasing N from 10 to 32 g m$^{-2}$ . High N plants had about 2.5% lower $\Delta$ values regardless of growth stages than low N plants across species and seed sizes. Carbon isotope discrimination was negatively correlated with WUE at anthesis but not at stem elongation.