• Journal of Photoscience
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• v.9 no.1
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• pp.5-7
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• 2002

Direct irradiation of carbonyl compounds such as some aldehydes, ketones and anthraquinone in N,N-dimethylamiline(DMA), without using other solvents, gave $\beta$-hydroxyamines as the major products. Irradiation of anthrone and DMA in methanol afforded ${\gamma}$-hydroxyamine. The structure of the photoproduct was confirmed by treatment with an acid to give a bicyclic compound.

• Korean Journal of Food Science and Technology
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• v.4 no.2
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• pp.72-76
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• 1972

Seven new hydroxyamine derivatives of 2,2'-methylene bis(3,4,6-trichloroacetoxy benzene) were synthesized by the Mannich reactions. 13 strains of microorganisms were tested for sensitivity to these derivatives by both paper disk method and tube dilution method. Of these compounds, -NHOH compound displays the most effective antimicrobial activity in vitro against Brevibacterium ammoniagenes, Staphylococcus aureus and Bacillus subtilis. Its minimal inhibitory concentration is $1.6{\mu}g/ml$ for Brevibacterium ammoniagenes, and $5{\mu}g/ml$ for Staphylococcus aureus and Bacillus subtilis.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.3
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• pp.326-333
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• 1984

The oxidation rate of krill lipids is very slow and no peroxides are accumulated even after long storage. By means of various chromatographic techniques and mass spectrophotometry, the primary antioxidant has been identified as ${\alpha}$-tocopherol. The phospholipid fractions did not show any antioxidative activity but peroxide-decomposing properties of total lipids depended upon the phospholipid contents. The peroxide-decomposing activities of phospholipids were due to the presence of polar materials generated during the storage. The most peroxide-decomposing fractions of oxidized krill lecithin by DEAE-cellulose column chromatography was low-molecule fraction (mean molecular weight: 182) and high-molecule fraction (mean molecular weight: 1942) was the next. The separation of peroxide-decomposing properties from low-molecule fraction was achieved by partitioning between chloroform and methanol/water. The methanol/water fraction showed strong peroxide-decomposing activities and main component of this fraction was assumed hydroxyamine compounds derived from choline.

• Polymer(Korea)
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• v.39 no.1
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• pp.165-168
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• 2015

Thermoresponsive polymers were successfully synthesized by a combination of atom transfer radical polymerization (ATRP) and Cu(I)-catalyzed 1,3-dipolar cycloaddition of azide and alkynes (click chemistry). Poly(2-hydroxyethyl methacrylate) (PHEMA) was synthesized by ATRP, followed by introduction of alkyne groups using pentynoic acid, leading to HEMA-alkyne. Homopolymers having secondary amine groups, tertiary amines with hydroxyethyl and hydroxypropyl groups were synthesized by adding 2-azido-N-ethyl-ethanamine, 2-[(2-azidoethyl)amino]ethanol, and 2-[(2-azidoethyl)amino]propanol, respectively, to the PHEMA-alkyne backbone using click chemistry. Molecular weight (MW), molecular weight distribution (MWD), and click reaction efficiency were determined by gel permeation chromatography (GPC) and $^1H$ NMR spectroscopy. The transmission spectra of the 1.0 wt% aqueous solutions of the resulting polymers at 650 nm were measured as a function of temperature. Results showed that the lower critical solution temperature (LCST) could be easily controlled by the length of the hydroxyalkyl groups.

• Journal of Photoscience
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• v.1 no.1
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• pp.47-52
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• 1994

Effects of HgCl$_2$-treatment on electron transport, chlorophyll a fluorescence and its quenching were studied using isolated barley (Hordeum vulgare L. cv. Albori) chloroplasts. Depending on the concentration of HgCI$_2$, photosynthetic oxygen-evolving activities of photosystem II (PS II) were greatly inhibited, whereas those of photosystem I (PS I) were slightly decreased. The inhibitory effects of HgCl$_2$ on the oxygen-evolving activity was partially restored by the addition of hydroxyamine, suggesting the primary inhibition site by HgCl$_2$2-treatment is close to the oxidizing site of PS tl associated with water-splitting complex. Addition of 50 $\mu$M HgCI$_2$ decreased both photochemical and nonphotochemical quenching of chlorophyll fluorescence. Especially, energy dependent quenching (qE) was completely disappeared by HgCl$_2$-treatment as observed by NH$_4$CI treatment. In the presence of HgCI$_2$, F'o level during illumination was also increased. These results suggest that pH gradient across thylakoid membrane can not be formed in the presence of 0 $\mu$M HgCl$_2$. In addition, antenna pigment composition might be altered by HgCl$_2$-treatment.

• Journal of the Korean Chemical Society
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• v.39 no.8
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• pp.657-665
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• 1995

The oxidation of various benzyl ethers and benzyl alkyl ethers to benzoates has been studied in two-phase system of $CH_3CO_2Et$ and aqueous NaOCl (6.6 mol eq.). The oxidant N-oxo-4-methoxy-2,2,6,6-tetramethylpiperidium bromide (N-oxoammonium salt) was prepared in situ and recycled by addition of 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl (0.03 mol eq., 4-methoxy-TEMPO), co-catalyst KBr (0.03mol eq.) and second oxidant NaOCl. Thus the catalytic amount of 4-methoxy-TEMPO was used. An adjustment of the pH value of below 8.0 was also required for this reaction with 2.5 hr of reaction time at 0∼5$^{\circ}C$. Under these conditions benzyl ethers were oxidized to benzoates. The selectivity of oxidation of benzyl alkyl ethers is dependent on the acidity of hydrogen and steric effect of alkyl group.

• The Korean Journal of Mycology
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• v.15 no.2
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• pp.99-170
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• 1987

The production and properties of laccase(E.C.1.10.3.2) from Coriolus versicolor were studied. The results were as follows; The nutritional optimum conditions for laccase production were 1% indulin At, 0.3% peptone 0.1% $KH_2PO_4$, 0.02% $MgSO_4$, 0.1 mg% $CuSO_4$.and 0.005 mg% thiamine HCI. The optimum temperature and pH of laccase production were $25^{\circ}C$ and 5.0, and respectively, and the cultural period was 20 days. The optimum pH and temperature for the activity were 4.6 and $40^{\circ}C$, respectively. The enzyme was almost stable under the temperature of $40^{\circ}C$ and within the pH range of 4.0-5.0. The enzyme was stable at $40^{\circ}C$ for 30 min. $Cu^{++}$, $Fe^{++}$ and $Ca^{++}$ activated the enzyme activity, but $Mn^{++}$ and $Hg^{++}$ were inhibited. The enzyme was totally inhibited by 1 mM sodium azide and 1 mM potassium cyanide, and partly inhibited by EDTA and hydroxyamine.