• Bulletin of the Korean Chemical Society
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• v.18 no.9
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• pp.961-965
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• 1997

1H NMR spectra of 3,3-dimethylpiperidine (1) at -70 to 30 ℃ exhibit gradual change from slow to rapid exchange between two alternate chair forms. The exchange rate constant was determined as a function of temperature by simulating the line shape of the signal from the two methyl groups using the modified Bloch equations. The resulting free energy of activation is ΔG* = 44.4±1.9 kJ mol-1 at 298 K. The 1H NMR spectrum of a D2O or dimethylsulfoxide-d6 (DMSO-d6) solution containing 1 and [SiW11CoⅡO39]6- exhibits separate signals for the free ligand and the complex, indicating that the ligand exchange is slow on the NMR time scale. In D2O the piperidine ring is frozen as a chair form even at room temperature with the cobalt ion bonded to the axial position of the nitrogen atom. When DMSO-d6 is added to the D2O solution, the NMR spectral change suggests that a rapid exchange occurs between the chair form and another conformer. It is proposed that the conformation of ^b1^b coordinated to [SiW11CoⅡO39]6- in DMSO-d6 is close to a twist form.

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.3
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• pp.307-315
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• 1988

This experiment was conducted to find out the effects of fertilizer-N and co-inoculation of the Rhizobium japonicum and the Azospirillum lipoferum on nodulation, $N_2$-fixation, and growth of soybean under in situ conditions. The results obtained were summarized as follows: 1. The yield of soybean dry matter was significantly greater in the R. japonicum alone, and the mixed inoculation of R. japonicum and A. lipoferum than those of un-inoculation. But inoculum applied by different strains did not significant effect on plant growth. The effects of nitrogen applied on soybean dry matter were higher in the ammonium sulfate than potassium nitrate, and decreased with increasing rates of two forms of nitrogen applied regardless of nitrogen source. 2. Acetylene redution activity was more increased in a single inoculation of R. japonicum than those of the mixed inoculation of the R. japonicum and the A. lipoferum, in cases of Danyeup cultivar, regardless of the form of combined nitrogen used. 3. Nodule mass and total nitrogenase activity per plant showed the positively significant effect in the interrelationship between dry matter of soybean and some factors related to nitrogen fixation efficiency. 4. The highest symbiotic effect in Danyeup cultivar was obtained when a single R. japonicum 84 Dy-1 strain was inoculated and fertilized with 18 mM potassium nitrate.

• Korean Journal of Soil Science and Fertilizer
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• v.17 no.3
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• pp.242-252
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• 1984

A port experiment was conducted to compare the effect of chemical forms of nitrogen fertilizers on the rice growth and soil characteristics. The nitrogen fertilizers used for this study were ammonium sulfate, ammonium nitrate, ammonium chloride and urea. The results are summarized as follows. 1. The differences in pH of the soil and surface water between treatments during the first week after fertilizer application were great and the pH values were in the order of urea > ammonium nitrate > ammonium sulfate > ammonium chloride treatment. However the differences were insignificant after the first week. 2. The differences in pH of the air-dried soil somewhat increased and pH values were in the order of urea > ammonium nitrate > ammonium chloride > ammonium sulfate treatment. 3. Sulfur contents of the soil and the rice leaf and N content of the rice leaf were highest when ammonium sulfate was applied. But there were few differences between the treatments in total N content of the soil and in P, K, Ca and Mg contents of the soil and the rice leaf. 4. Number of tillers and dry matter weight of the rice plant were highest in ammonium sulfate plot throughout all the growing stages. 5. Number of panicle per hill was highest in ammonium sulfate plot, and this brought the highest grain yield in ammonium sulfate plot. The lowest grain yield in ammonium nitrate plot resulted from the lowest number of panicle per hill and ripened grain ratio.

• Korean Journal of Ecology and Environment
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• v.52 no.1
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• pp.50-64
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• 2019

Recently, quantitative analyses of food web structure based on carbon and nitrogen stable isotopes are widely applied to environmental assessments as well as ecological researches of various ecosystems, particularly rivers and streams. In the present study, we analyzed carbon and nitrogen stable isotope ratios of POM (both planktonic and attached forms), zooplankton, benthic macroinvertebrates and fish collected from 6 sites located at Nakdong River. Samples were collected from upstream areas of 5 weirs (Sangju, Gangjeong-Goryeong, Dalseong, Hapcheon-Changnyeong, and Changnyeong-Haman Weirs) and one downstream area of Hapcheon-Changnyeong Weir in dry season (June) and after rainy season (September). We suggested ranges of their carbon and nitrogen stable isotope ratios and calculated their trophic levels in the food web to compare their temporal and spatial variations. Trophic levels of organisms were relatively higher in Sangju Weir located at upper part of Nakdong River, and decreased thereafter. However, the trophic levels were recovered at the Changnyeong-Haman Weir, the lowest weir in the river. The trophic level calculated by nitrogen stable isotope ratios showed more reliable ranges when they were calculated based on zooplankton than POM used as baseline. The suggested quantitative ecological information of the majority of biological communities in Nakdong River would be helpful to understand the response of river food web to environmental disturbances and can be applied to various further researches regarding the quantitative approaches for the understanding food web structure and function of river ecosystems as well as restoration.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.128-136
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• 1998

Most of total nitrogen in the surface soil exists in organic forms, of which amino acid-N is the major fraction. By-product fertilizers provide soil with humic substances, and humic acid is an essential component of humus. Amino acids(AAs) are easily converted to inorganic-N forms and thus play an important role in N fertility. This experiment was conducted to investigate the contents and distributions of AAs in humic acids which were extracted from the commercial by-product fertilizers of different composting materials. Total contents of AAs in humic acids ranged from 1.2 to 5.6%, of which neutral AAs were the highest with ranges of 0.8~4.5%. AAs contents in fertilizers composted from the plant residues such as leaf litter, sawdust and bark were in an order of neutral>acidic>basic AAs. In contrast, those from animal wastes, such as poultry and pig manures, were in an order of neutral>basic>acidic AAs. Distributions of total, acidic and neutral AAs were in the respective order of leaf litter>sawdust>pig manure>poultry manure>peat, bark>sawdust>leaf litter>peat and leaf litter>sawdust>bark>peat. Distributions of the basic AAs were in the reversed order of the acidic AAs. In bark fertilizer with increasing compost maturity, contents of the acidic AAs were increased in compensation for the decreases in those of neutral and basic AAs. Results demonstrated that distributions of amino acids in humic acid of by-product fertilizers were different from composting raw materials and degrees of humification.

• Journal of the Korean Chemical Society
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• v.35 no.6
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• pp.645-652
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• 1991

The stability constants$(K_f)$ of the complexes of some transition and post-transition metal ions (Co(Ⅱ), Ni(Ⅱ), Cu(Ⅱ), Zn(Ⅱ), Cd(Ⅱ), Pb(Ⅱ), Hg(Ⅱ)) with $N_2O_3$-donor macrocyclic ligand, 1,15-diaza-3,4 : 12,13-dibenzo-5,8,11-trioxacyclooctadecane ($NtnOdienH_4$), have been determined by potentiometry in aqueous solution at $25^{\circ}C$. Log $K_f$ values of the complexes were : Co(Ⅱ): 3.83, Ni(Ⅱ) : 4.56, Cu(Ⅱ) : 7.74, Zn(Ⅱ) : 4.98, Cd(Ⅱ) : 3.91, Pb(Ⅱ) : 6.65, and Hg(Ⅱ) : 14.87. The order of stabilities of transition metal complexes was the same as the natural order of stability proposed by Williams-Irving. In post-transition metal complexes, the order of stabilities was Cd(Ⅱ) < Pb(Ⅱ) < Hg(Ⅱ), and the covalent character in metal ion-donor atoms bonds appeared a dominant factor in the stability. In methanol solution, each metal ion forms 1 : 1 complex, while Ni(Ⅱ) ion forms both 1 : 1 and 1 : 2 complexes. It was confirmed by $^1H-$ and $^{13}C-$NMR spectral study that the nitrogen atoms in the ligand were major contributors for the complexation of post-transition metal ions with the ligand. It was shown, by elementry analysis, electrical conductivity and magnetic susceptibility measurements, and spectral analysis, that solid Cu(Ⅱ)-and Zn(Ⅱ)-complexes have a distorted octahedral and a tetrahedral structure, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.12 no.2
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• pp.91-97
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• 1979

1. Nitrogenous compounds of-organic materials as nitrogen sources for Korean ginseng were characterized according to their solubility and chemical forms. 2. The extractable fractionation was as follows : Yakto group : non-extractable N > acid hydrolyzable N > acid nonhydrolyzable N > water sol. N, Litter group : acid hydrolyzable N > non-extractable N > water sol. N > acid non-hydrolyzable N, Bone meal : acid hydrolyzable N > water sol. N > acid non-hydrolyzable N. 3. Nitrogenous compounds in the water sol. fraction were : Yakto group and Litter group : humus N > amino acid N > nitrate N (recognized only in Yakto group) > ammonia N > hexosamine N > amide N, Bone meal : amino acid N > humus N > ammonia N > amide N. And nitrogenous compounds in the acid hydrolyzable fraction were : amino acid N > humus N ${\simeq}$ ammonia N > hexosamine N. 4. Availability was discussed about the major nitrogenous compounds (amino acid, humus and inorganic N) and the solubility.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.5
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• pp.659-666
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• 2009

Metabolizable protein (MP) supply and amino acid balance in the intestine were manipulated through selection of highly digestible rumen-undegradable protein (RUP) sources and protected methionine (Met) supplementation. Four ruminallycannulated, multiparous Holstein cows averaging 193${\pm}$13 days in milk were used in a 4${\times}$4 Latin square design to assess N utilization and milk production responses to changes in RUP level, post-ruminal RUP digestibility and protected Met supplementation. Treatments were A) 14.0% crude protein (CP), 8.0% rumen degradable protein (RDP) and 6.0% RUP of low intestinal digestibility (HiRUP-LoDRUP); B) 14.1% CP, 8.1% RDP and 6.0% RUP of high intestinal digestibility (HiRUP-HiDRUP); C) 13.1% CP, 7.9% RDP and 5.2% RUP of high intestinal digestibility (LoRUP-HiDRUP), and D) 13.1% CP, 7.9% RDP and 5.2% RUP of high intestinal digestibility plus rumen escape sources of Met (LoRUP-HiDRUP+Met). Experimental diets were formulated to have similar concentrations of RDP, net energy of lactation ($NE_L$), neutral detergent fiber (NDF), acid detergent fiber (ADF), calcium, phosphorus and ether extract using the NRC model (2001). Results showed that dry matter intake (DMI), production of milk fat and protein were similar among treatments. Milk production was similar for diet HiRUP-LoDRUP, HiRUP-HiDRUP and LoRUP-HiDRUP+Met, and significantly higher than diet LoRUP-HiDRUP. Milk fat and protein percentage were higher for cows receiving HiDRUP treatments, with the greatest increases in the diet LoRUP-HiDRUP+Met. There was no significant change in ruminal pH, $NH_3g-N$ and volatile fatty acid (VFA) concentration among all treatments. Apparent digestibility of dry matter (DM), CP, NDF and ADF and estimated bacterial CP synthesis were similar for all treatments. Nitrogen intakes, blood and milk urea-N concentrations were significantly higher for cows receiving HiRUP diets. Urine volume and total urinary N excretion were significantly lowered by LoRUP diets. Lowering dietary RUP level while supplementing the highly digestible RUP source with rumen escape sources of Met resulted in similar milk production, maximal milk fat and protein concentration and maximum N efficiency, indicating that post-ruminal digestibility of RUP and amino acid balance in the small intestine can be more important than total RUP supplementation.

• Microbiology and Biotechnology Letters
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• v.48 no.1
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• pp.38-47
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• 2020

This study was conducted to investigate both plant growth-promoting and plant disease- controlling activities of bacterial strains isolated from soil. All the isolated strains were able to grow at various temperatures. All the strains, except ANG40, showed antagonistic effects against various phytopathogenic fungi. This antagonism can be ascribed to the production of siderophores and antibiotic substances. In addition, all the strains showed abilities such as nitrogen fixation, phosphate solubilization, and siderophore production. These results suggest that nitrogen, phosphorus, and iron can be converted into forms that can be easily absorbed by the plants for their growth. Analysis of the growth-promoting properties revealed that ANG51 produced 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase and indole-3-acetic acid (IAA) both of which are related to ethylene production. In contrast, the other strains were found to have only IAA-producing ability. Therefore, this study suggests that Pseudomonas geniculata ANG3, Exiguobacterium acetylicum ANG40, and Burkholderia stabilis ANG51, which were selected through analysis of comparative advantages for both plant growth promotion and disease-controlling activity, may be used as biological agents.

• Journal of Plant Biology
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• v.36 no.4
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• pp.363-370
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• 1993

Experiments with non-nodulated alfalfa (Medicago sativa L. cv, Europe) plants grown in hydroponic cuiture, were carried out to estimate the remobiJization of nitrogen (N) reserves and to investigate the transported forms of reduced soluble-N in xylem during regrowth following shoot removal. Endogenous N remobilization were estimated by $^{15}N$ labelling and amino acids in xylem sap were analysed. The, $^{15}N$ contents of ~egr9wing leaves and stems increased as a result of remobilization of N reserves mainly from root ,system, Regrowing leaves were a stronger sink than regrowing stems, with about tWo-thirds of remobilized 15N being recoved in leaves. Endogenous N in lateral roots accounted for about 46% of the total N reserves used for regrowth, while tap roots accounted for 23%, About 72% of total endogenous N remobilized to regrowing shoot, occurred during the first 10 days of regrowth, The outflow of reduced soluble-N (mainly amino acids) was greater than that of protein-N, while the latter was the largest storage pool in tap root and lateral roots. It is suggested that amino acids-N was the most readily avaiable form of N reserves. Asparagine, which repre5ented about 75% of amino acids-N in xylem sap, was the main transported form of reduced N. Its relative contents, during the first 10 days of regrowth, decreased from 75% to 59%. This decline was accompanied by compensatory increase in the relative contents of asparatate and glutamine.