• Journal of Environmental Science International
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• v.18 no.3
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• pp.299-308
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• 2009

We manufactured PVA-derived hydrogels using a foam generation technique that has been widely used to prepare colloidal gas aphrons(CGA). These gels were differentiated to the conventional gels such as for medical or pharmaceutical applications, which have tiny pores and some crystalline structure. Rather these should be used in de-pollution devices or adhesion of cells or biomolecules. The crosslinkers used in this work were amino acid, organic acid, sugars and lipids(vitamins). The structures of the gels were observed in a scanned electron microscope. Amino acids gels showed remarkably higher swelling ratios probably because their typical functional groups help constructing a highly crosslinked network along with hydrogen bonds. Boric acid and starch would catalyze dehydration while structuring to result in much lower water content and accordingly high gel content, leading to less elastic, hard gels. Bulky materials such as ascorbic acid or starch produced, in general, large pores in the matrices and also nicotinamide, having large hydrophobic patches was likely to enlarge pore size of its gels as well since the hydrophobicity would expel water molecules, thus leading to reduced swelling. Hydrophilicity(or hydrophobicity), functional groups which are involved in the reaction or physical linkage, and bulkiness of crosslinkers were found to be more critical to gel's cross linking structure and its density than molecular weights that seemed to be closely related to pore sizes. Microscopic observation revealed that pores were more or less homogeneous and their average sizes were $20{\mu}m$ for methionine, $10-15{\mu}m$ for citric acid, $50-70{\mu}m$ for L-ascorbic acid, $30-40{\mu}m$ for nicotinamide, and $70-80{\mu}m$ for starch. Also a sensory test showed that amino acid and glucose gels were more elastic meanwhile acid and nicotinamide gels turned out to be brittle or non-elastic at their high concentrations. The elasticity of a gel was reasonably correlated with its water content or swelling ratio. In addition, the PVA gel including 20% ascorbic acid showed fair ability of cell adherence as 0.257mg/g-hydrogel and completely degraded phenanthrene(10 mM) in 240 h.

• Journal of the Korean Chemical Society
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• v.33 no.4
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• pp.357-365
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• 1989

The positional parameters of framework atoms, cations, and water molecules in hydrated and dehydrated $Mg_4Na_4-A$, $Ca_6-A$, $Zn_5Na_2-A$ and $Co_4Na_4-A$ were determined by the optimization technique using some potential energy functions and VAIOA optimization program. Upon dehydration, cations in hydrated states move toward the framework oxygens of 6 rings. Frameworks of fully dehydrated zeolite A are more stable than those of fully dehydrated divalent cation exchanged Zeolite A. There are three different kinds of water molecules in divalent cation exchanged Zeolite A; W(III) (water molecules having hydrogen bonds), W(II) (water molecules associated with $Na^+$ ions), and W(I) (water molecules associated with divalent cations). Three different DTA endothermic peaks were observed corresponding to the dehydration of three different kinds of water molecules in divalent cation exchanged Zeolite A.

• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.553-558
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• 2003

The crystal structure of $[n-Bu_4N]_2[Mo_6O_{19}]$(TBAM) (n-Bu4N=tetrabutylammonium) has been determined by X-ray crystallography. It crystallizes in the monoclinic system, space group C2/c, with lattice parameters ${\alpha}$=16.314(5), b=17.288(5), c=17.776(4)${\AA}$ ${\beta}$=101.47(3), and Z=4. In $[Mo_6O{19}]^{2-}$ anion, Mo atoms occupy six vertices of octahedron and each Mo atom is coordinated by six oxygen atoms to adopt distorted octahedral coordination geometry. The average bond distance of Mo-Ot (terminal), Mo-Ob (bridged) and Mo-Oc (central) are 1.680 ${\AA}$, 1.931 ${\AA}$ and 2.325 ${\AA}$ respectively. In $[n-Bu_4N]^+$ cation, the N atom possesses a slightly distorted tetrahedral geometry. There are some potential extensive C-H ${\cdots}$ O hydrogen bonds in the lattice, by which connecte molecules and stabilize the crystal structure. Thermogravimetric analysis suggests that thermal decomposition of the title compound includes two transitions and it loses weight at 356.0 and 803.5 $^{\circ}$, respectively, and the residue presumable be $Mo_2O_2$. Accordingly, the title compound has high thermal stability.

• Journal of Life Science
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• v.25 no.2
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• pp.121-129
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• 2015

Alginates are found in marine brown seaweeds and in extracellular biofilms secreted by some bacteria. Previously, we reported an oligoalginate lyase from Sphingomonas sp. MJ-3 (MJ3-Oal) that had an exolytic activity and protein sequence homology with endolytic polymannuronate (polyM) lyase in the N-terminal region. In this study, the MJ3-Oal was tested for both exolytic and endolytic activity by homology modeling using the crystal structure of Alg17c from Saccharophagus degradans 2-40T. The tyrosine residue at the $426^{th}$ position, which possibly formed a hydrogen bond with the substrate, was mutated to phenylalanine. The FPLC profiles showed that MJ3-Oal degraded alginate quickly to monomers as a final product through the oligmers, whereas the Tyr426Phe mutant showed only exolytic alginate lyase activity. $^1H$-NMR spectra also showed that MJ3-Oal degraded the endoglycosidic bond of polyM and polyMG (polymannuronate-guluronate) blocks. These results indicate that oligoalginate lyase from Sphingomonas sp. MJ-3 probably catalyzes the degradation of both exo- and endo-glycosidic bonds of alginate.

• YAKHAK HOEJI
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• v.55 no.4
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• pp.319-323
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• 2011

Curcumin, of which a critical characteristic is the capacity of crossing the blood-brain barrier, has been reported to induce the expression of neuroprotective heme oxygenase (HO)-1. The aim of this study is to compare HO-1-inducing capacity and neuroprotective activity of curcumin, its demethoxy (demethoxycurcumin, DMC; bis-demethoxycurcumin, BDMC) and hydrogenated derivatives (tetrahydrocurcumin, THC) in mouse hippocampal HT22 cells. Curcumin attenuated glutamate-induced cell death through HO-1 expression. DMC lacking a methoxy group on one of the aromatic rings possessed slightly lower activity in HO-1 expression and neuroprotection than curcumin. Similarly, BDMC, which lacks two methoxy groups on both of the aromatic rings, showed less activity than curcumin. These findings suggest that the presence of methoxy groups on the aromatic ring is required to enhance neuroprotective HO-1 expression. The reduction of the diarylheptadienone chain of curcumin by hydrogen, as in THC, was accompanied by a complete loss of ability to induce HO-1 expression and neuroprotection, suggesting that the conjugated double bonds of the central seven-carbon chain of curcumin may be essential for its ability to induce neuroprotective HO-1 expression. Our findings may provide useful information for further development of neuroprotective HO-1 inducers.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.2
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• pp.201-210
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• 2018

In this study, we formulated oil-in-water emulsion composition for skin care products containing jadeite powder which is well known as far-infrared radiating material. Jadeite powder could sustain stable dispersion in aqueous solvents over a month and this helped mixing it high content in oil-in-water emulsion formulation. To identify the effect of jadeite as a far-infrared radiator materials relating to the skin surface temperature change, we applied emulsion formulation containing 2 weight percent jadeite powder onto facial skin surface and blank formulation together and analyzed surface temperature with thermo-vision. Our results showed that the temperature difference between jadeite powder formulation applied region and blank formulation reached to 1.5 ~ 2.0 degree Celsius. We also performed same test with nephrite powder and titanium dioxide powder but only jadeite powder containing formulation showed significant skin temperature change. To elucidate main cause of heat energy transfer, we tested heat radiation, energy dispersive spectrometer analysis and measured far infrared radiance emissivity, diffuse reflectance spectra and water evaporation rate. We found out jadeite powder could retard water evaporation effectively from the skin surface and resist temperature drop down. This is because of the innate chemical composition and surface structure of jadeite, which can bind with water molecules to form hydrogen bonds. It is concluded that we can develop novel skin care products for moisturizing and thermos with jadeite powder.

• Journal of the Korean Chemical Society
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• v.37 no.6
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• pp.599-603
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• 1993

Crystal structure of bis(1,2-diaminopropane)palladium(II) bis(oxalato)palladate(II) has been determined by X-ray crystallography. Crystal data: $Pd_2C_{10}H_{10}N_{4}O_{8}$, $M_W$ = 573.09, orthorhombic, space group $P_{ccn}$ (No = 56), a = 16.178(5), b = 16.381(6), c = 6.685(2)$\{AA}$, V = 1771.6 $\{AA}^3$, $M_W$W = 573.09, $D_c$ = 2.014 g${\cdot}c\;m^{-3}$, Z = 4, T = 294K, F(000) = 1056.0 and $\mu$ = 20.466 c$m^{-1}$. The intensity data were collected with $Mo-K\alpha$ radiation (${\lambda}$ = 0.7107 $\AA)$ on an automatic four-circle diffractometer with a graphite monochromater. The structure was solved by Patterson method and refined by full matrix least-squares methods using Pivot weights. The final R and S values were R = 0.065, $R_W = 0.059, R_{all}$ = 0.065 and S = 4.315 for 605 observed reflections. Both cation and anion complexes are essentially planar and have dihedral angle of $18(l)^{\circ}$ between thier planes. In the crystal structure, they do not have the Magnus's salt type mixed stacks; instead, the complex anions form regular stacks along the c-axis with the M-M bond length of $3.343(5)\AA$ and their stacks are surrounded by the complex cations through hydrogen bonds with the nitrogen-oxygen distances of 2.94(3) and $3.31(4)\AA.$

• Korean Journal of Crystallography
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• v.7 no.1
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• pp.36-43
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• 1996

The crystal structure Tris(ethylenediamine)nickel(II)Dichromate has been determined by X-ray crystallography. Crystal data: a=8.268(2), b=13.865(2), c=14.921(2)Å, γ=102.04(2)°, V=1672.9(5)Å3, Z=4, Monocline, P21/b (space group No.=14), Dcalc=1.806 gcm-3, μ=24.05 cm-0.1. The intensity data were collected with Mo-Kα radiation(λ=0.7107Å) on an automatic four-circle diffractometer with a graphite monochromator. The structure was solved by Patterson method and refined by full matrix least-square methods using unit weights. The final R and S values were R=0.045, Rw=0.051, Rall=0.059 and S=2.171for 2248 observed reflections. The two carbon atoms of a ring of Ni(en)-ion were split into crossed four atoms. In consideration of α- and β-angles of two rings of a disordered ethylenediamine of Nien3-ion and the hydrogen bonds between Ni(en)3-cation and Cr2O7-anion, the configuration of Ni(en)3-ion is assumed to be disordered with Λδδδ and Λδδλ.

• Food Science and Preservation
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• v.24 no.1
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• pp.145-152
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• 2017

In this study, near infrared (NIR) spectroscopy known as a non-destructive analysis technique was applied to investigate peptide cleavage and consequent release of amino acids in soybean lumps as affected by its moisture content and incubation time during fermentation at 25 for 3 weeks. The NIR spectra of the soybean lump semi-dried and soaked in saline water showed that absorption intensity around 1,400 nm originating from hydrogen bonds of water decreased and absorption band shifted to 1,430 nm as moisture content decreased during incubation at 25 for 3 weeks. In addition, absorption around 2,050 nm which was assigned to amino groups increased as incubation time increased. NIR spectra data from 1,000 to 2,250 nm showed higher accuracy in the discriminant analysis between outside and inside parts of fermented soybean lumps than visible spectra result. NIR spectroscopy for the amino acid and moisture contents in traditional fermented soybean lumps showed relatively good accuracy with the multiple correlation coefficient ($R^2$) of 0.91 and 0.81, respectively, and root mean square error of cross validation (RMSECv) of 0.23 and 0.83%, respectively, in partial least square regression (PLSR). These results indicate that NIR spectral observations could be applicable to control the fermentation process for preparation of soybean products.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.4
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• pp.421-429
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• 2018

Hydrazine based reductive dissolution applied on magnetite oxide was investigated. Dissolution of Fe(II) and Fe(III) from magnetite takes place either by protonation, surface complexation, or reduction. Solution containing hydrazine and sulfuric acid provides hydrogen to break bonds between Fe and oxygen by protonation and electrons for the reduction of insoluble Fe(III) to soluble Fe(II) in acidic solution of pH 3. In terms of dissolution rate, numerous transition metal ions were examined and Cu(II) ion was found to be the most effective to speed up the dissolution. During the cycle of Cu(I) ions to Cu(II) ions, the released electron promoted the reduction of Fe(III) and Cu(II) ions returned to Cu(I) ion due to the oxidation of hydrazine. In the experimental results, the addition of a very low amount of cupric ion (about 0.5 mM) to the solution increased the dissolution rate about 40% on average and up to 70% for certain specific conditions. It is confirmed that even though the coordination structure of copper ions with hydrazine is not clear, the $Cu(II)/H^+/N_2H_4$ system is acceptable regarding the dissolution performance as a decontamination reagent.