• Bulletin of the Korean Chemical Society
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• v.35 no.7
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• pp.2043-2048
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• 2014

Two isomers of a new tetraaza macrotricycle 2,2,4,9,9,11-hexaazamethyl-1,5,8,12-tetraazatricyclo[$10.2.2^{5.8}$]-octadecane ($L^2$) containing additional N-$CH_2CH_2$-N linkages, C-meso-$L^2$ and C-racemic-$L^2$, have been prepared by the reaction of 1-bromo-2-chloroethane with C-meso-$L^1$ or C-racemic-$L^1$ ($L^1$ = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane). Both C-meso-$L^2$ and C-racemic-$L^2$ react with copper(II) ion to form $[Cu(C-meso-L^2)]^{2+}$ or $[Cu(C-racemic-L^2)]^{2+}$ in dehydrated ethanol, but do not with nickel(II) ion under similar conditions. Crystal structure of [Cu(C-racemic-$L^2$)($H_2O$)]$(ClO_4)_2$ shows that the complex has distorted square-pyramidal coordination geometry with an apically coordinated water molecule. Unexpectedly, the Cu-N distances [2.016(3)-2.030(3) ${\AA}$] of [Cu(C-racemic-$L^2$)($H_2O$)]$(ClO_4)_2$ are longer than those [1.992(3)-2.000(3) ${\AA}$] of [Cu(C-racemic-$L^1$)($H_2O$)]$(ClO_4)_2$. As a result, $[Cu(C-racemic-L^2)(H_2O)]^{2+}$ exhibits weaker ligand field strength than $[Cu(C-racemic-L^1)(H_2O)]^{2+}$. The copper(II) complexes readily react with CN- ion to yield the cyano-bridged dinuclear complex $[Cu_2(C-meso-L^2)_2CN]^{3+}$ or $[Cu_2(C-racemic-L^2)_2CN]^{3+}$. Spectra and chemical properties of $[Cu(C-meso-L^2)]^{2+}$ and $[Cu_2(C-meso-L^2)_2CN]^{3+}$ are not quite different from those of $[Cu(C-racemic-L^2)]^{2+}$ and $[Cu_2(C-racemic-L^2)_2CN]^{3+}$, respectively.

• Macromolecular Research
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• v.16 no.5
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• pp.441-445
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• 2008

A series of aluminum complexes supported by $\beta$-ketoamino, ligand-bearing, 3-position substituents $LAlEt_2$ ($L=CH_3C(O)C(Cl)=C(CH_3)NAr\;(L_1)$, $L=CH_3C(O)C(H)=C(CH_3)NAr\;(L_2)$, $L=CH_3C(O)C(Ph)=C(CH_3)NAr\;(L_3)$, and $L=CH_3C(O)C(Me)=C(CH_3)NAr\;(L_4)$, $Ar=2,6-^iPr_2C6H_3$) were synthesized in situ and employed in the ring-opening polymerization (ROP) of $\varepsilon$-caprolactone ($\varepsilon$-CL) and cyclohexene oxide (CHO). The 3-position substituents on the $\beta$-ketoamino ligand backbone of the aluminum complexes influenced the catalyst activity remarkably for both ROP of $\varepsilon$-CL and CHO. Aluminum $\beta$-ketoamino complexes displayed different catalytic behavior in ROP of $\varepsilon$-CL and CHO. The order of the catalytic activity of $LAlEt_2$ was $L_1AlEt_2$>$L_2AlEt_2$>$L_3AlEt_2$>$L_4AlEt_2$ for ROP of $\varepsilon$-CL, being opposite to the electron-donating ability of the 3-position substituents on the $\beta$-ketoamino ligand, while the order of the catalytic activity for ROP of CHO was $L_1AlEt_2$>$L_3AlEt_2$>$L_4AlEt_2$>$L_2AlEt_2$. The effects of reaction temperature and time on the ROP were also investigated for both $\varepsilon$-CL and CHO.

• Bulletin of the Korean Chemical Society
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• v.28 no.1
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• pp.77-80
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• 2007

As neurofilament proteins are major cytoskeletal components of neuron, abnormality of neurofilament is proposed in brain with neurodegenerative disorders such as Parkinson's disease (PD). Since oxidative stress might play a critical role in altering normal brain proteins, we investigated the oxidative modification of neurofilament-L (NF-L) induced by the reaction of cytochrome c with H2O2. When NF-L was incubated with cytochrome c and H2O2, the protein aggregation was increased in cytochrome c and H2O2 concentrationsdependent manner. Radical scavengers, azide, formate and N-acetyl cysteine, prevented the aggregation of NFL induced by the cytochrome c/H2O2 system. The formations of carbonyl group and dityrosine were obtained in cytochrome c/H2O2-mediated NF-L aggregates. Iron specific chelator, desferoxamine, prevented the cytochrome c/H2O2 system-mediated NF-L aggregation. These results suggest that the cytochrome c/H2O2 system may be related to abnormal aggregation of NF-L which may be involved in the pathogenesis of PD and related disorders.

• Korean journal of food and cookery science
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• v.14 no.4
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• pp.327-332
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• 1998

In the fermentation of Yulmoo Mulkimchi, various ratios of Yulmoo to water (l/l.14, l/l.5, 1/2, l/2.75, 1/4) were prepared and fermented at 4$^{\circ}C$, 15$^{\circ}C$, 25$^{\circ}C$ for up to 10 days. According to the fermentation time, the pH, acidity, total vitamin C content and microbial growth in Mulkimchi samples were determined together with sensory evaluation. Fermentation temperature on water addition ratio didn't show any difference in pH and microbial growth of Mulkimchi. However, low ratio of water resulted in high acidity and vitamin C content in Mulkimchi. In terms of acid odor and acid taste, the least water addition (l/l.4) sample was significantly strong than those of other samples. The ratio of Yulmoo to water, l/2 showed the highest overall sensorial acceptability and followed by l/l.5, l/l.4, l/2.75 and 1/4 samples. It was found that the content of vitamin C and acid taste of Mulkimchi have correlation with its acceptability.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.3
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• pp.283-288
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• 2011

In this paper, an adaptive signal tracking loop for a GPS L1/L2C/L5 receiver is designed. The design parameters is adjusted according to the receiver's operating conditions such as the signal strength and the receiver dynamics by using the different characteristics of GPS L1, L2C and L5 signal. Simulation results show that the tracking accuracy of the proposed signal tracking loop is better than those of L1, L2C and L5 only signal tracking loop.

• Applied Biological Chemistry
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• v.3
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• pp.25-48
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• 1962

The polysaccharide C prepared from gum tragacanth powder (U. S. P. grade) by the precipitation method with 85% ethanol was a neutral polysaccharide, $[{\alpha}]^{30}_D-72.2$. The polysaccharide C consisted of L-rhamnose, D-xylose, L-arabinose and D-galactose in the molar ratio 2:1:17:9 (Table 1, 2, 3, ). The polysaccharide C was methylated with dimethylsulphate and 40% NaOH, and Purdies regent. The hydrolyzate of fully methlated product ($[{\alpha}]^{22}_D-102$ in chloroform, the methoxy content 40.6%) was composed of 2, 3, 5-tri-O-methyl-L-arabofuranose (I), 3,4-di-O-methyl-L-rhamnopyranose (II), 2,3-di-O-methyl-D-xylose (III), 2,3,4-tri-O-methyl-D-galactopyranose (IV), 2,4-di-O-methyl-L-arabopyranose (?), 2,4-di-O-methyl-D-galactose(VI), 2-O-methyl-D-arabinose (VII), and L-arabopyranose(VIII) (Table 4, 5, and Fig. 4). The first partial hydrolysis (A) of the polysaccharide C with 0.05N-HCl for 4.5 hours at $80-85^{\circ}C$ released only L-arabinose: the second hydrolysis (B) with 0.1N-HCl for 5 hours at $80-85^{\circ}C$, L-arabinose and D-galactose; and the third hydrolysis (C) with 0.3N-HCl at $90-95^{\circ}C$ in sealed tube, L-rhamnose, D-xylose, L-arabinose and D-galactose. From the unhydrolyzate A' were found L-rhamnose, D-xylose, L-arabinose, and D-galactose; from B' L-rhamnose, d-xylose, L-arabinose and D-galactose; and from C' D-xylose and D-galactose respectively (Table 6). The periodate consumption and formic acid production of the polysaccharide C were measured at various time intervals. After 120 hours periodat was consumed by 1.23 mole per $C_5H_8O_4$ and formic acid was produced 0.78 mole per $C_5H_8O_4$ (Table 7). Although a definite chemical structure for this polysaccharide C may not be formulated, experimental data, especially, from methylation, partial hydrolysie and determination of its molar ratio, and periodate analysis showed that the polysaccharide C is a highly branched polysaccharide and would be constructed of galactoaraban as a main chain residue and L-arabofuranose, D-galactopyranosyl $(1{\rightarrow}1)$-L-arabofuranose, D-xylopyranosyl $(1{\rightarrow}2)$-L-rhamnopyranosyl $(1{\rightarrow}1)$-L-arabofuranose, and L-rhamnopyranosyl $(1{\rightarrow}1)$-arabofuranose, and D-galactopyranosyl-$(1{\rightarrow}2)$-L-arabopyranosyl-$(1{\rightarrow}1)$-I-arabofuranose as a branch chain or end group (page 21).

• Journal of Ginseng Research
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• v.11 no.2
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• pp.136-144
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• 1987

Biosynthesis of saponins from acetate, mevalonate and squalene using root slices of panax ginseng C.A. Meyer was investigated. The sliced roots (2g) were incubated with the reaction mixture containing 20 M sodium acetate ($500\mu$Ci [U-$^{l4}C$]-acetate),10 mM mevalonate ($25\mu$Ci [2-$^{l4}C$]-mevalonate) or 10 mM swidme ($10\mu$Ci [4,8,12,13,17,21-$^3H$]-squalene) respectively at $30^{\circ}C$ for 72 hours. Biosynthesis of labelled ginseng saponine from [U-l4C]-acetate, [2-$^{l4}C$]-mevalonate and [4,8,12,13,17,21-$^3H$]-squalene was confirmed by autoradiography. Analysis of the products from [U-$^{l4}C$]-acetate by T.L.C. showed that the % radioactivities in panaxadiol, panaxatriol, squalene and mevalonate were found to be 2.1%, 2.7%, 2.6% and 0.2% respectively. Some of the sugars were also highly labelled. Analysis of the products from [2-$^{l4}C$]-mevalonate by T.L.C. showed that squalene was highly labelled and the products from [4,8,12,13,17,21-$^3H$]-squalene showed that panaxadiol, panaxatriol and sterol were highly labelled. From the above results, it was suggested that saponine might be synthesized from acetate via mevalonate-squalene route as expected in ginseng root.

• Parasites, Hosts and Diseases
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• v.22 no.1
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• pp.11-20
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• 1984

A number of studies on the papillae of cercariae of trematodes reported that the papillar patterns (or chaetotaxy) of cercariae might be an excellent method to attain better understanding of the digenetic trematodes (Richard, 1971 ; Short and Cartrett, 1973; Bayssade-Dufour, 1979) . The present study was aimed to determine the number, distribution pattern and structure of the sensory papillae of Metagonimus yokogawai cercariae, and to elucidate the chaetotaxy of this digenetic trematode. M. yokogawai cercariae were pipetted from a vial in which infected snails (Semisulcospira libertina) had been kept for 3 hours. The snails were collected from an endemic area of M. yokogawai, Boseong river in west-southern part of Korea. Observations of papillae were based on light microscopy of those stained with silver nitrate, and on scanning electron microscopy The results are summarized as follows: 1, All papillae observed were uniciliated. 2. Cilia in anterior tip were shorter than the others in other portions. 3. The body papillae were arranged in essentially symmetrical patterns, Total number of the papillae was 126(63 pairs) in average; anterior tip 40(20 pairs), ventral 20(10 pairs), lateral 42(21 pairs), and caudal 8(4 pairs). 4. The chaetotany of M. yokogawai cercaria was: Ci cycle ($3+3C_{I}V,{\;}2+2C_{I}L,{\;}2+3C_{I}D),{\;}C_{II}{\;}cycle(2C_{II}V,{\;}1C_{II}L,{\;}2C_{II}D),{\;}C_{lll}{\;}cycle{\;}(1+lC_{III}V,{\;}1C_{IlI}L),{\;}C_{IV}{\;}cycle{\;}(1C_{IV}V,{\;}IC_{lV}L){\;}in{\;}cephalic{\;}region:{\;}A_I(1A_{IV}V,{\;}1+2A_{I}L,{\;}1A_{I}D),{\;}A_{II}(1A_{II}V,{\;}1+3A_{II}L,{\;}1A_{II}D),{\;}A_{III}(1A_{III}V,{\;}1+1A_{III}L,{\;}1A_{III}D){\;}and{\;}A_{IV}(1A_{IV}V,{\;}2A_{IV}L)$ in antacetabular region: $1M_{I}V{\;}and{\;}2M_{I}L$ in median: $1+1P_{I}L,{\;}1P_{II}L,{\;}1P_{II}D,{\;}1P_{III}L,{\;}1P_{IV}L{\;}and{\;}1P_{IV}D$ in postacetabular region: 2-2-2-2 in caudal region.

• Journal of Microbiology and Biotechnology
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• v.2 no.2
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• pp.73-77
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• 1992

The effect of a nisin-producing Lactococcus lactis spp. lactis (L. lactis) on the growth and attachment of Listeria monocytogenes Scott A and Brie 1 on stainless steel and their growth in Brain Heart Infusion broth was determined. Viable cells of Listeria decreased rapidly after 9~12 hr of incubation at $21^{\circ}C$ and after 6~9 hr of incubation at $32^{\circ}C$ in the presence of L. lactis. The number of L. monocytogenes Scott A attached to stainless steel in pure culture was $2.5{\times}10^3/\textrm{cm}^2{\;}at{\;}21^{\circ}C{\;}and{\;}2.3{\times}10^3/\textrm{cm}^2{\;}at{\;}32^{\circ}C$ after 48 hr of incubation, but was only $10/\textrm{cm}^2{\;}at{\;}21^{\circ}C{\;}and{\;}1.1{\times}10/\textrm{cm}^2{\;}at{\;}32^{\circ}C$ in the presence of L. lactis. Results from L. monocytogenes strain Brie 1 were similar to those from strain Scott A. The population of L. monocytogenes Scott A which attached to stainless steel with previously adherent L. lactis was $1.8{\times}10^2/\textrm{cm}^2{\;}at{\;}21^{\circ}C{\;}and{\;}8.2{\times}10^2/\textrm{cm}^2{\;}at{\;}32^{\circ}C$, whereas the population attached to sterile stainless steel was $1.2{\times}10^3/\textrm{cm}^2{\;}at{\;}21^{\circ}C{\;}and{\;}2.1{\times}10^2/\textrm{cm}^2{\;}at{\;}32^{\circ}C$. For L. monocytogenes Brie 1, the attached population of the control was $1.6{\times}10^4/\textrm{cm}^2{\;}at{\;}21^{\circ}C{\;}and{\;}3.2{\times}10^2/\textrm{cm}^2{\;}at{\;}32^{\circ}C$, and on stainless steel with adherent L. lactis, it was $1.1{\times}10/\textrm{cm}^2{\;}at{\;}21^{\circ}C{\;}and{\;}6.9{\times}10/\textrm{cm}^2{\;}at{\;}32^{\circ}C$. Surface adherent L. lactis was less inhibitory to attachment of L. monocytogenes on stainless steel than a liquid culture inoculum. Listeria attached to stainless steel survived dry storage for 20 days both in the presence and absence of adherent lactococci.

• Journal of Digital Convergence
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• v.20 no.2
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• pp.345-351
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• 2022

For simple undirected graph G=(V,E), L(2,1)-coloring of G is a nonnegative real-valued function f : V → [0,1,…,k] such that whenever vertices x and y are adjacent in G then |f(x)-f(y)|≥ 2 and whenever the distance between x and y is 2, |f(x)-f(y)|≥ 1. For a given L(2,1)-coloring c of graph G, the c-span is λ(c) = max{|c(v)-c(v)||u,v∈V}. L(2,1)-coloring number λ(G) = min{λ(c)} where the minimum is taken over all L(2,1)-coloring c of graph G. In this paper, based on Harary's Theorem, we use Tabu Search to figure out the existence of Hamiltonian Path in a complementary graph and confirmed that if λ(G) is equal to n(=|V|).