• Journal of Life Science
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• v.22 no.3
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• pp.387-397
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• 2012

In this study, we focused on myomoduline A (MMA) released from the central nervous system of Aplysia kurodai. The primary structure of MMA is Pro-Met-Ser-Met-Leu-Arg-Leu-$NH_2$. This peptide is the same as that of the myomodulin family peptide found in other mollusks. The purified MMA showed a modulating activity of phasic contraction on the anterior byssus retractor muscle (ABRM) of Mytilus edulis. In order to study the relationship between the structure and biological activity of MMA, we synthesized MMA, Des[$Pro^1$]-MMA, Des[$Pro^1,Met^2$]-MMA, Des[$Pro^1,Met^2,Ser^3$]-MMA, and MME. The amino acid sequences of Des[$Pro^1$]-MMA, Des[$Pro^1,Met^2$]-MMA, and Des[$Pro^1,Met^2,Ser^3$]-MMA were Met-Ser-Met-Leu-Arg-Leu-$NH_2$, Ser-Met-Leu-Arg-Leu-$NH_2$, and Met-Leu-Arg-Leu-$NH_2$, respectively. MMA and synthetic peptides were tested on ABRM in M. edulis as well as muscle preparations in Achatina fulica. At $1{\times}10^{-8}$ M or lower, MMA showed a potentiating effect on phasic contraction of the ABRM, but this peptide had an inhibitory effect at $1{\times}10^{-6}$ M or higher. Both MMA and its analogs stimulated a contractile response on the crop and a relaxed catch-relaxing response on the penial retractor muscle of A. fulica. These results suggest that Met-Leu-Arg-Leu-$NH_2$ in MMA is the minimum structure required for the regulation of the contraction of ABRM, as well as the reproductive and digestive activities of mollusks.

• Journal of the Korean Ceramic Society
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• v.31 no.5
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• pp.505-512
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• 1994

It has been reported that a biocement obtained by mixing CaO-SiO2-P2O5 glass powder and ammonium phosphate solution has biocompatibility as well as high strength. However, the compositional dependence on its hardening and hydroxyapatite formation phenomena has not been studied. Therefore, the main objective of this work is to study the effects of P2O5, MgO in CaO-SiO2 system glass on the hardening and hydroxyapatite formation. When more than 50 mole% of CaO containing CaO-SiO2 glasses was reacted with ammonium phosphate solution, CaNH4PO4.H2O crystal was formed, but the glass with less than 50 mol% of CaO formed (NH4)2HPO4 and NH4H2PO4 crystals which are derived from ammonium phosphate solution without reacting with the glasses. As the amount of P2O5 in CaO-SiO2-P2O5 glass system was increased, the formation of CaNH4PO4.H2O crystal was enhanced. When those hardened samples were reacted with tris-buffer solution, hydroxyapatite was obtained only for the sample with CaNH4PO4.H2O. While the substitution of MgO for CaO decreased the formation of CaNH4PO4.H2O crystal. MgNH4PO4.H2O crystla was formed in high MgO containing glass, which did not react with tris-buffer solution.

• Environmental Engineering Research
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• v.23 no.1
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• pp.28-35
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• 2018

$17{\alpha}-ethinylestradiol$ (EE2), a synthetic estrogen which interfere the endocrine and reproductive function in living organisms, has been found extensively to be deposited into municipal wastewater treatment plants and the environment via human excretion. EE2 has long been known to be efficiently cometabolized by ammonia-oxidizing bacteria (AOB) during ammonia ($NH_3$) oxidation. Current study aims to investigate the effect of culture history on the biotransformation of EE2 by nitrifying sludge which was enriched under different ammonia loading rates in continuous flow reactors. Result showed that past growth condition largely affected not only the metabolic rate of $NH_3$ oxidation but also EE2 cometabolism. Sludge previously acclimated with higher $NH_3$ loads as well as sludge dominated with AOB belong to high growth cluster (Nitrosomonas europaea-Nitrosococcus mobilis) showed higher rate of EE2 biotransformation than those one being acclimated with lower $NH_3$ loads because of its ability to provide more reducing power from $NH_3$ oxidation. Moreover, the correlation between the degradation rates of $NH_3$ and EE2 was higher in sludge being acclimated with higher load of $NH_3$ in comparison with other sludge. Implication of the findings emphasized the role of volumetric $NH_3$ loading rate in determining EE2 removal in wastewater treatment system.

• Journal of the Korean Chemical Society
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• v.36 no.2
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• pp.230-237
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• 1992

The correlation was investigated between the observed heat of ligation and calculated bond energy for square planar and octahedral Cu(II) complexes by EHMO (Extended Huckel Molecular Orbital) method. It was found that net charge of $Cu^{2+}$ ion of both square planar $[Cu(H_2O)_{4-x}(NH_3)_x]^{2+}$(X = 0, 1, 2,${\ldots}$4) and octahedral $[Cu(H_2O)_{6-x}(NH_3)_x]^{2+}$complexes (X = 0, 1, 2,${\ldots}$6) is decreased with substituting $NH_3$ for $H_2O$ molecule. It was found that a good relationship exists between the observed heat of ligation and the calculated bond energy. From this fact, we can obtain a linear equation ${\Delta}H$ = 0.1194$E_{diss}$ + 0.4718, theoretical equation.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.451-455
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• 2015

An excess application of N fertilizer causes physiological and morphological disorder known as ammonium ($NH_4{^+}$) toxicity in Chinese cabbage and it has been to be an issue for appropriate N fertilizer management. Hence, the pot experiment was conducted in order to evaluate the alleviating effect of the application of the easily decomposable carbohydrate on $NH_4{^+}$ toxicity in Chinese cabbage. Four levels of urea at 0, 160, 320, and $640kg\;N\;ha^{-1}$, represented as T1, T2, T3, and T4, respectively, were applied. In order to evaluate the alleviating effect of the application of the easily decomposable carbohydrate (sucrose) at T3 and T4 where $NH_4{^+}$ toxicity had occurred, five levels of sucrose were applied to meet C/N ratios of 0, 2, 4, 6, and 10, respectively. Our results showed that the $NH_4{^+}$ toxicity was observed at T3 and T4 at 5 days after treatment (DAT). $NH_4{^+}$ toxicity contributed to decrease fresh weight, length of leaves, length of root, and number of leaves significantly (p<0.05). The application of sucrose as a source of mitigating $NH_4{^+}$ toxicity had a good performance at T3 with the alleviating effect as 73 % and reduced in $NH_4{^+}-N$ content in soil at 29 DAT. In the maximum N rate of T4, however, sucrose application recovered it as 32 % only compared to T2 even though the same C/N ratio was treated. Consequently, sucrose as the easily decomposable carbohydrate played crucial role to reduce $NH_4{^+}$ concentration in soil and finally alleviated $NH_4{^+}$ toxicity in plant.

• Clean Technology
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• v.13 no.2
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• pp.122-126
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• 2007

When ammonia ($NH_3$) gas was supplied to a biofilter packed with bio-carrier made of waste polyurthane and worm cast. No odor gases were detected at the outlet of the biofilter when $NH_3$ gas was supplied to the biofilter at the space velocity(SV) of $50\;h^{-1}$ until the inlet $NH_3$ concentration increased to $4\;{\sim}\;454\;ppmv$. The gradual inlet $NH_3$ concentration was set and the removal efficiency of $NH_3$ gas was measured at each condition, while the SV of $NH_3$ increased step by step from 100 to $400\;h^{-1}$. The maximum possible inlet $NH_3$ loading was $11.38\;g-NH_3{\cdot}m^{-3}{\cdot}h^{-1}$ and $34.42\;g-NH_3{\cdot}m^{-3}{\cdot}h^{-1}$ while maintaining the removal efficiency of 100% when the SV was $50\;h^{-1}$ and $100 \;h^{-1}$, respectively. The maximum $NH_3$ loading was $71.28 \;g-NH_3{\cdot}m^{-3}{\cdot}h^{-1}$ with the $NH_3$ removal efficiency of 99.85% at SV $300\;h^{-1}$.

• Korean Journal of Environmental Agriculture
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• v.34 no.3
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• pp.155-160
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• 2015

BACKGROUND: Objective of this study was to investigate adsorption characteristics of $NH_4-N$ to biochar produced from rice hull in respective to mitigation of greenhouse gases. METHODS AND RESULTS: $NH_4-N$ concentration was analyzed by UV spectrophotometer. For adsorption experiment of $NH_4-N$ to biochar, input amount of biochar was varied from 0.4 to 10 g/L with 30 mg/L $NH_4-N$ solution. Its adsorption characteristic was investigated with application of Langmuir isotherm. Adsorption amount and removal rates of $NH_4-N$ were decreased at 53.9% and increased at 20.2% with 10 g/L compared to 0.4 g/L, respectively. The sorption of $NH_4-N$ to biochar produced from rice hull was fitted well by a Langmuir model. The largest adsorption amount of $NH_4-N$ ($q_m$) and binding strength constant (b) were calculated as 0.4980 mg/g, and 0.0249 L/mg, respectively. It was observed that dimensionless constant ($R_L$) was 0.58. CONCLUSION: It was indicated that biochar produced from rice hull is favorably absorbed $NH_4-N$, because this value lie within 0< $R_L$ <1.

• Resources Recycling
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• v.17 no.1
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• pp.38-42
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• 2008

This study was carried out to investigate the solubility of vanadium in ammoniacal solution and precipitation of $NH_4VO_3$ as a function of temperature and addition of ammonia salt. Higher solution temperature is required to get high solubility of vanadium and the vanadium concentration of solution was 16.8g/L at $90^{\circ}C$ with the solution of 20 g/L $(NH_4)_2CO_3$ and 2.5M $NH_4OH$. From this solution, vanadium could be precipitated up to 99.8% with adding 20 g/L $NH_4Cl$, 72 hours settling time at $25^{\circ}C$.

• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.64-70
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• 2022

In this study, an experiment was performed by adding Sb during NH3-selective catalytic reduction (NH₃-SCR) while varying calcination temperatures from 400 to 700 ℃ to improve the low temperature denitrification efficiency of VWTi catalyst. As a result, VWSbTi(500) and VWSbTi(600) catalysts corresponding to Sb calcination temperatures of 500~600 ℃ showed the best denitrification performance at low temperatures below 300 ℃. BET, XRD, Raman, XPS, H₂-TPR, and NH₃-TPD analyses were performed In order to confirm physicochemical properties according to the calcination temperature. In the case of VWSbTi(500) and VWSbTi(600), an acid site increased with the generation of W=O species, and superb activity at low temperatures was exhibited due to the excellent redox characteristics and increase in electron density of tungsten. Furthermore, in the case of VWSbTi(700), as the crystalline V₂O₅ structure was formed, the denitrification efficiency decreased. Thus the optimum calcination temperature during Sb addition process was confirmed.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.3
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• pp.117-125
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• 2002

This study experimented a possibility of advanced treatment through microorganism that converts $NH_3-N$ to organic nitrogen in wastewater contaminated by ammoniac nitrogen unlike conventional nitrogen removal process. After distributing three kinds of special bacteria that use $NH_3-N$ as a substrate, when those bacteria were cultured in no salt condition and salt condition (3% NaCl), M11 showed better growth in salt condition and M12 showed better growth in no salt condition. However M7l grew well in both no salt condition and salt condition. In the test of glucose effect, maximum growth and removal rate were observed in glucose concentration of 5g/L but in high concentration (1000mg/L as $NH_3-N$) of $NH_3-N$ growth and removal rate were low. Removal rate was the highest in 100mg/L $NH_3-N$ and the fact that concentration of $NO_2-N$ and $NO_3-N$ didn't increase assumed $NH_3-N$ was converted to organic nitrogen. Optimum concentration of $K_2HPO_4$ for phosphorous supply and buffer was 5g/L. Special bacteria distributed could use $NO_2-N$ and $NO_3-N$ as well as $NH_3-N$ as substrates. This study showed that when growth rate of bacteria was high removal rate also was high. It is possible to apply as a method to treat wastewater polluted by $NH_3-N$.