• The Korean Journal of Pesticide Science
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• v.14 no.3
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• pp.183-190
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• 2010

To search the new potent herbicidal agents by receptor-based approach, the interactions between receptor and substrate molecules from molecular docking to acetyl-CoA carboxylase(PDB code: 3K8X) of 2-(4-(6-chloro-2-benzoxazolyl)oxy)phenoxy-N-phenylpropionamide analogues (1-38) as substrate molecules were performed and discussed quantitatively. The most of the substrate molecules were formated 2 H-bonds between carbonyl oxygen atom of the substrate molecules and the amino acid residues (Ala1627 and Ile1735) in binding site of acetyl-CoA carboxylase (ACCase). But, the substrate molecules such as $R_l$=Acetyl substituents (6 & P9) were formated 3 H-bonds between H-bond acceptors in the substrate molecules and the H-bond donors in three amino acid residues including the rest residue (Gly 1998). Therefore, the inhibitory activity factors of the substrate molecules against ACCase are due to the H-bonding characters that will be able to apply to the optimization of herbicidal agents.

• Microbiology and Biotechnology Letters
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• v.12 no.4
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• pp.277-283
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• 1984

In the forward reaction (ADP formation) of the adenylate kinase from baker's yeast, dissociation constants from binary complexes are higher by a factor of about 4 times then those from at ternary complexes. In the reverse reaction, dissociation constants from the binary complexes are 2 times higher then those from the ternary complexes. The enzyme showed activities against various nucleotide triphospate in following orders; ATP 100, UTP 18, ITP 9 and GTP 5, of the necleotide monophosphate. only dAMP showed 33% activity of that AMP as phosphate acceptor. Divalent cations were required in enzyme reaction in following orders; $Mg^{2＋}$ 100, Co$^{2＋}$ 57, Mn$^{2＋}$ 54, $Ca^{2＋}$ 51, Ni$^{2＋}$ 10 and Sn$^{2＋}$ 6. AMP, as a substrate inhibitor, competitively inhibited the adenylate kinase at pH 7.2 or 8.0. Inhibition constants of the enzyme showed greater dependence on the pH of the reaction mixture, which was the lower Ki values under higher pH. Adenosine pentaphospho adenosine was competive inhibitor to the enzyme against all substrate, and it showed the same Ki values, 2.9mM. Further, PEP was competive inhibitor with respect to AMP and non-competive inhibitor with respect to MgATP. Adenylate kinase from bakers yeast was similar to mitochondrial type of animal in the contents of aianine, leucine and asparagine or asparatic acid differing from muscle type enzyme. Based on the results and observation, characteristic of yeast adenylate kinase resembled the adenylate kinase of mitochondrial type from animals. Further, difference of characteristics in adenylate kinasa depending upon the workers might be due to the difference of strain used.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.2
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• pp.18-23
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• 2016

Self-assembly of organic molecules is formed spontaneously on surfaces by electrostatic interaction with substrate. This research has shown that the self-assembly improves safety and handling tractability of high-energetic materials (HEMs). According to the recent study, control of the specific crystal size for reducing the internal defects is mightily important, because the internal defects are a factor in unstability of HEMs. In turn, we performed self-assembly of organic molecules and HEMs by using nano-sized HEMs, which were produced by drowing-out or milling/crystallization. Surface modification efficiency was decided by size distribution, zeta-potential, friction sensitivity and electrostatic charge.

• Applied Biological Chemistry
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• v.48 no.3
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• pp.189-200
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• 2005

Biological nitrogen fixation is an important process for academic and industrial aspects. This review will briefly compare industrial and biological nitrogen fixation and cover the characteristics of biological nitrogen fixation studied in Azotobacter vinelandii. Various organisms can carry out biological nitrogen fixation and recently the researches on the reaction mechanism were concentrated on the free-living microorganism, A. vinelandii. Nitrogen fixation, which transforms atmospheric $N_2$ into ammonia, is chemically a reduction reaction requiring electron donation. Nitrogenase, the biological nitrgen fixer, accepts electrons from biological electron donors, and transfers them to the active site, FeMo-cofactor, through $Fe_4S_4$ cluster in Fe protein and P-cluster in MoFe protein. The electron transport and the proton transport are very important processes in the nitrogenase catalysis to understand its reaction mechanism, and the interactions between FeMo-cofactor and nitrogen molecule are at the center of biological nitrogen fixation mechanism. Spectroscopic studies including protein X-ray crystallography, EPR and $M{\ddot{o}}ssbauer$, biochemical approaches including substrate and inhibitor interactions as well as site-directed mutation study, and chemical approach to synthesize the FeMo-cofactor model compounds were used for biological nitrogen fixation study. Recent research results from these area were presented, and finally, a new nitrogenase reaction mechanism will be proposed based on the various research results.

• Journal of Korea Water Resources Association
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• v.52 no.11
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• pp.917-929
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• 2019

Denitrification in streams is of great importance because it is essential for amelioration of water quality and accurate estimation of $N_2O$ budgets. Denitrification is a major biological source or sink of $N_2O$, an important greenhouse gas, which is a multi-step respiratory process that converts nitrate ($NO_3{^-}$) to gaseous forms of nitrogen ($N_2$ or $N_2O$). In aquatic ecosystems, the complex interactions of water flooding condition, substrate supply, hydrodynamic and biogeochemical properties modulate the extent of multi-step reactions required for $N_2O$ flux. Although water flow in streambed and residence time affect reaction output, effects of a complex interaction of hydrodynamic, geomorphology and biogeochemical controls on the magnitude of denitrification in streams are still illusive. In this work, we built a two-dimensional water flow channel and measured $N_2O$ flux from channel sediment with different bed geomorphology by using static closed chambers. Two independent experiments were conducted with identical flume and geomorphology but sediment with differences in dissolved organic carbon (DOC). The experiment flume was a circulation channel through which the effluent flows back, and the size of it was $37m{\times}1.2m{\times}1m$. Five days before the experiment began, urea fertilizer (46% N) was added to sediment with the rate of $0.5kg\;N/m^2$. A sand dune (1 m length and 0.15 m height) was made at the middle of channel to simulate variations in microtopography. In high- DOC experiment, $N_2O$ flux increases in the direction of flow, while the highest flux ($14.6{\pm}8.40{\mu}g\;N_2O-N/m^2\;hr$) was measured in the slope on the back side of the sand dune. followed by decreases afterward. In contrast, low DOC sediment did not show the geomorphological variations. We found that even though topographic variation influenced $N_2O$ flux and chemical properties, this effect is highly constrained by carbon availability.

• Child Health Nursing Research
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• v.6 no.2
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• pp.132-143
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• 2000

The purpose of this correlational study was to find the correlation between the infant temperament, mother-infant interaction, and child-rearing environment. The subjects of this study were 37 dyads of healthy mothers and healthy infants. Data were collected from 15th of March to 3rd of September, 1999. Convenient sampling was done at Obstetric wards of one University hospital, and demographic data were collected before discharge. At one month and three month postpartum, we visited subject's home, and collected the data on the infant temperament, and also video taped the mother-infant interaction during feeding. In addition, child-rearing environment was checked by researcher according to HOME(Home Observation for Measurement of the Environment) at three months postpartum. Mother-infant interactions were rated according to the NCAST Feeding Scale later. Data were analyzed by window SPSS program, and correlations between the infant temperament, mother-infant interaction, and child-rearing environment were analyzed by Pearson's correlational coefficient. The results were as follows: 1. Infant temperament. 1) Among the subscales of infant temperament, mothers perceived cuddliness and amenability most positively at one month, and responsivity and amenability most positively at three months. 2) In subscale analysis of stability, amenability, responsivity, and persistence were stable with the time. 3) Significant relationships were found between the malleability and amenability, between the malleability and responsivity at one month, and also between the malleability and amenability, and between the malleability and cuddliness at three months. 2. Correlations of infant temperament and mother-infant interaction. 1) There was no significant relationship between the infant temperament and mother-infant interaction at one month. 2) There was a significant relationship between the infant temperament and mother-infant interaction at three months(r=.335, p<.05). In subscale analysis, there were significnt relationships between the total score of infant temperament and maternal sensitivity to infant's cues(r=.372, p<.05), and between the total score of infant temperament and maternal response to infant's distress (r=.331, p<.05). 3. Correlations of infant temperament and child-rearing environment. 1) There was no significant relationship between the total score of infant temperament at one month and total score of HOME at three months. In subscal analysis, the total score of infant temperament at one showed significant relationships with the organization of environment(r=.413, p<.05), and the emotional, verbal response at three months(r=.337, p<.05). 2) There was a significant relationship between the total score of infant temperament at three months and the total score of HOME at three months (r=.599, p<.01). In subscal analysis, the total score of infant temperament at three months showed significant relationships with the organization of environment(r=.410, p<.05), maternal involvement(r=.482, p,.01), and the emotional, verbal response(r=.695, p<.01) at three months. 4. Correlations of mother-infant interaction and child-rearing environment. There was a significant relationship between the maternal score of mother-infant interaction at one month and three months and the total score of HOME at three months (r=.474, p<.01; r=.452, p<.01). In conclusion, it was proved that infant temperament had significant relationships with mother-infant interaction and child-rearing environment, especially when the infants were getting older. This showed the possibility for changeability of infant teperament by the maternal factors.

• Child Health Nursing Research
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• v.19 no.1
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• pp.39-48
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• 2013

Purpose: The purposes of this study were to assess the parenting stress in mothers of premature infants and stress related characteristics of mothers and infants. Methods: The methodology was a cross sectional survey study using self-report questionnaires. Participants in this study were 36 mothers of infants with corrected ages of 4 months to 12 months who were born prematurely. Data were analyzed using t-test, ANOVA, and Pearson correlation with the SPSS WIN 19.0 program. Results: The mean score for parenting stress in mothers of premature infants was $74.639{\pm}17.570$, indicating that the mothers actually experienced stress. When mothers were able to have some private time, parenting stress was statistically significantly lower. When the residential status was having one's own house and the local community provided informational support regarding child nurturing, there was a statistically significant decrease in the sub-category of particular infant temperament. There was a statistically significant positive correlation between mothers' depression and parenting stress. Conclusion: These results indicate that there is a need for nursing interventions to increase mothers' private time and to include informational support regarding health management of children including developmental status assessment from local communities.

• Journal of Korean Home Economics Education Association
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• v.16 no.2
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• pp.73-84
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• 2004

The Purpose of this study was to investigate the relationship between elementary and middle school students’ depression and their mothers’ parenting stress. The subject were 659 elementary and middle school students and their mothers. In the study, elementary and middle school students depression appeared significant difference to their sex/grade. Parenting stress related to learning expectation appeared significant difference to elementary and middle school students’ sex/grade. Elementary and middle school students depression appeared significant difference to Parenting stress. And as for correlating parenting stress to elementary and middle school students’ depression, the significance appeared in these factors.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.213-220
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• 2023

Mixed-matrix membranes (MMMs), which are composed of a polymer matrix filled with high-performance fillers as a dispersed phase, have been intensively studied for gas separations for the past 30 years. It has been demonstrated that MMMs exhibit superior gas separation performance compared to polymer membranes and are more scalable than polycrystalline membranes. Despite their potential, the commercialization of MMMs has yet to be reported due to several challenging issues. One of the major challenges of MMMs is the non-ideal interface between the continuous polymer phase and dispersed phase, which can result in defect formation (i.e., interfacial voids, etc.). With respect, many MMM studies have focused on addressing the issues through scientific approaches. The engineering approaches for facile and effective large-scale fabrication of MMMs, however, have been relatively underestimated. In this review paper, a novel strategy for fabricating MMMs in a facile and scalable manner using in situ metal-organic framework (MOF) formation is introduced. This new MMM fabrication methodology can effectively address the issues facing current MMMs, likely facilitating the commercialization of MMMs.

• Applied Microscopy
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• v.32 no.4
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• pp.385-398
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• 2002

The purpose of the present study is to investigate whether stromal cells supporting specific microenvironment for hematopoiesis of bone marrow are affected by toxicants and therapeutic drugs such as antibiotics and anticancer drugs and whether laminin-1 is associated with such effects. SD rats were intraperitoneally injected with 75 mg/kg of cyclophosphamide which is widely used to treat infant's solid tumor, leukemia and myeloma and sacrificed after 3 days, 1 week, 3 weeks or 5 weeks of injection. The bone marrow extracted and paraffin-sectioned was analyzed using immunohistochemical staining. A part of tissues was subjected to electron microscopy following reaction with rabbit anti-laminin antibody, biotinylated goat anti-rabbit IgG conjugated with 12 nm gold particles, and staining with uranyl acetate. 1. The bone marrow tissue at day 3 post injection with cyclophosphamide displayed dilated venous sinus, partial necrotic death, and decreased number of hematopoietic cells. Laminin-1 was intensively stained in the reticular and adipose tissues. 2. Up to 5 weeks post injection, laminin-1 was stained at a low level in the stromal tissue of bone marrow and the number of hematopoietic cell was increased. 3. Deposition of the gold particle which represents laminin-1 expression was observed at the highest level in the stromal cells of bone marrow obtained 3 days after injection, and decreased after 1 to 5 weeks. These results suggest that stromal cells which play a role in supporting microenvironment for bone marrow hematopoiesis augment induction of laminin-1 expression and activation upon administration of cyclophosphamide.