• Bulletin of the Korean Chemical Society
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• 제35권8호
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• pp.2410-2414
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• 2014

A kinetic study is reported on nucleophilic substitution reactions of Y-substituted-phenyl picolinates (7a-7h) with a series of cyclic secondary amines in 80 mol % $H_2O$/20 mol % DMSO at $25.0{\pm}0.1^{\circ}C$. Comparison of the kinetic results with those reported previously for the corresponding reactions of Y-substituted-phenyl benzoates (1a-1f) reveals that 7a-7h are significantly more reactive than 1a-1f. The Br${\o}$nsted-type plot for the aminolysis of 4-nitrophenyl picolinate (7a) is linear with ${\beta}_{nuc}=0.78$, which is typical for reactions proceeding through a stepwise mechanism with expulsion of the leaving group being the rate-determining step. The Br${\o}$nsted-type plots for the piperidinolysis of 7a-7h and 1a-1f are also linear with ${\beta}_{lg}=-1.04$ and -1.39, respectively, indicating that the more reactive 7a-7h are less selective than the less reactive 1a-1f to the leaving-group basicity. One might suggest that the enhanced reactivity of 7a-7h is due to the inductive effect exerted by the electronegative N atom in the picolinyl moiety, while the decreased selectivity of the more reactive substrates is in accord with the reactivity-selectivity principle. However, the nature of intermediate (e.g., a stabilized cyclic intermediate through the intramolecular H-bonding interaction for the reactions of 7a-7h, which is structurally not possible for the reactions of 1a-1f) is also responsible for the enhanced reactivity with a decreased selectivity.

• 대한수의학회지
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• 제38권1호
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• pp.53-63
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• 1998

Total of 1085 swine sera (1996-1997) from nation-wide were tested for the presence of antibodies to influenza A virus. Fifty nine percent of the tested sera showed seropositive by HI test. Positive sera consisted of 24--- of H3, 15--- of H1, and 20--- of the sample had both antibodies, respectively. Sera collected from various region represented 7~27--- seropositivity to H1N1, 15~25--- to H3N2, respectively. Swine influenza field isolate from nasal swab was characterized antigenically and genetically to elucidate its relatedness with other known strains of influenza A virus. The study was focused on the HA gene which is related to pathogenecity and antigenic variability of the influenza virus. By RT-PCR using influenza A/H1N1 specific primers, influenza virus H1N1 specific DNA fragment was amplified from A/Swine/Iowa/15/30(H1N1), US field isolate but not in H3N2 strain. PCR products were sequenced by dideoxy chain termination method to determine nucleotide homology with other strains of influenza A virus. The US field isolate and A/Swine/Indiana/1726/88 strain had 97--- of nucleotide homology and 98--- of amino acid homology. Based on the results obtained from this experiment, the field isolate was genetically related to A/Swine/Indiana/1726/88 and had higher homology with A/Swine/Indiana/1726/88 than with classical swine influenza virus, A/Swine/Iowa/15/30. The field isolate had no amino acid changes at the antigenic site compare to that of the A/Swine/Indiana/1726/88. The proteolytic enzyme cleavage site between HA1 and HA2 had no alteration and the amino acid arginine was intact. There is no evidence has been found that the field isolate has genetic shift or genetic drift which might altered antigenic determinant.

• BMB Reports
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• 제45권11호
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• pp.653-658
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• 2012

After the outbreak of the swine-origin influenza A H1N1 virus in April 2009, World Health Organization declared this novel H1N1 virus as the first pandemic influenza virus (2009 pH1N1) of the $21^{st}$ century. To elucidate the characteristics of 2009 pH1N1, the growth properties of A/Korea/01/09 (K/09) was analyzed in cells. Interestingly, the maximal titer of K/09 was higher than that of a seasonal H1N1 virus isolated in Korea 2008 (S/08) though the RNP complex of K/09 was less competent than that of S/08. In addition, the NS1 protein of K/09 was determined as a weak interferon antagonist as compared to that of S/08. Thus, in order to confine genetic determinants of K/09, activities of two major surface glycoproteins were analyzed. Interestingly, K/09 possesses highly reactive NA proteins and weak HA cell-binding avidity. These findings suggest that the surface glycoproteins might be a key factor in the features of 2009 pH1N1.

• 한국가금학회지
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• 제46권3호
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• pp.173-183
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• 2019

조류인플루엔자 바이러스 H7 subtype에 속하는 바이러스 중 일부는 가금류에 감염할 경우 고병원성이 발휘된다. 또 H7 아형 AIV중 일부는 사람에 감염하여 사망 등을 유발할 수도 있다. 본 연구는 야생조류로부터 분리된 H7 아형 조류인플루엔자 바이러스 6주(H7N7 아형 4주, H7N1 아형 2주)를 대상으로 8개 유전자 분절 전체의 염기서열을 분석하여 병원성, 사람 감염 가능성 등 그 특성을 조사하였다. 계통유전학적 분석결과, 국내에서 분리된 H7 아형 분리주들은 8개 유전자(HA, NA, PB2, PB1, PA, NP, M, NS) 모두 Eurasian lineage로 분류되었으나, Eurasian lineage 내에서도 각기 다른 sublineage로 분류되어 유전적 다양성이 있는 것으로 분석되었다. 한국 분리주 6주는 HA 단백질 분절부위 아미노산은 두 종류(PEIPKGR 및 PELPKGR)의 motif를 가지고 있었으나, 모두 저병원성 바이러스 특성을 가지고 있었다. 숙주세포 결합 특이성과 관련 있는 HA 단백질 receptor-binding site를 분석한 결과, 한국 분리주 모두는 사람 세포 수용체 결합특이성보다는 조류 세포 수용체 결합 특이성을 가지는 것으로 나타났다. 사람 감염 가능성을 높게 하는 부위에서의 아미노산 치환(PB2 단백질의 E627K 및 PB1단백질의 I368V)도 나타나지 않았고, 또한 NA stalk region에서의 결손도 관찰되지 않았다. 이상의 결과를 미루어 볼 때 한국 야생조류에서 분리된 H7 아형 6주 모두는 저병원성 바이러스로 최근 중국에서 사람 감염이 나타나고 있는 H7N9 바이러스와는 유전적으로 다른 계열의 바이러스인 것으로 판단된다.

• 한국자기공명학회논문지
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• 제11권2호
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• pp.64-72
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• 2007

[ $^1H$ ] nuclear magnetic resonance (NMR) experiments have been performed at 30 - 300 K and 7 T to investigate dynamics of hydrogen bond network in the single crystal $(NH_4)_3H(SO_4)_2$. The two proton sites, ammonium proton and hydrogen-bond proton, are identified from the $^1H$ NMR MAS spectrum at 340 K. As temperature decreases, the $^1H$ NMR spectrum shifts to the higher frequency side with a larger linewidth. The spectrum at 65 K shows a distinctive change in line shape toward the ferroelectric transition at 63 K. The measured values of $T_1$ for ammonium and hydrogen-bond protons are similar in the whole range of temperature. $T_1$ of $^1H$ NMR shows a gradual decrease down to 120 K and starts to steeply increase below 100 K. Then $T_1$ shows abrupt decrease below 70 K with a sharp minimum at 63 K, where the ferroelectric transition occurs. This temperature dependence of spectrum and $T_1$ clearly prove that the large change in the dynamics of hydrogen bond network is associated with the ferroelectric phase transition at 63 K.

• Advances in environmental research
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• 제3권2호
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• pp.151-162
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• 2014

Among the combination of 4 different second metals and 3 different noble metals, Ni 10%-Pd 1%/hematite (Ni(10)-Pd(1)/H) showed best tetrachloroethylene (PCE) removal (75.8%) and production of non-toxic products (39.8%) in closed batch reactors under an anaerobic condition. The effect of environmental factors (pH, contents of Ni and Pd in catalyst, and hydrogen gas concentration) on the reductive dechlorination of PCE by Pd-Ni/hematite catalysts was investigated. PCE was degraded less at the condition of Ni(5)/H (13.7%) than at the same condition with Ni(10)/H (20.6%). Removals of PCE were rarely influenced by the experimental condition of different Pd amounts (Pd(1)/H and Pd(3)/H). Acidic to neutral pH conditions were favorable to the degradation of PCE, compared to the alkaline condition (pH 10). Increasing Ni contents from 1 to 10% increased the PCE removal to 89.8% in 6 hr. However, the removal decreased to 74.2% at Ni content of 20%. Meanwhile, increasing Pd contents to 6% showed no difference in PCE removal at Pd content of more than 1%. Increasing H2 concentration increased the removal of PCE until 4% H2 which was maximumly applied in this study. Chlorinated products such as trichloroethylene, 1,1-dichloroethylene, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, and vinyl chloride were not observed while PCE was transformed to acetylene (24%), ethylene (5%), and ethane (11%) by Ni(10)-Pd(1)/H catalyst in 6hr.

• 약학회지
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• 제34권2호
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• pp.133-138
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• 1990

The reaction of 2-aminobenzamide with phthalic acid anhydride In dioxane produced a bicyclic product 2,8-dioxoisoindole(1,2,a) quinazoline (I) in addition to hydrolysis product 2(2-Carboxyphenyl)-1,2-2H-quinazoline-4-one (II). The yields were 64% and 30% respectively. On the other hand, the same reaction in DMF afforded compound (I) and 2(2N-dimethyl carbamyl phenyl)-1,4-2H-quinazoline-4-one (III) in 30% and 60% yield respectively. The compound III was also obtained by the reaction of compound II with dimethylamine. However the reaction of 2-aminobenzamide with neat succinic acid anhydride gave only bicyclic product 2,8-oxopyrrolidine (2,1,a)-1,4-2H-quinazoline (IV) in 93%.

• 대한화학회지
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• 제38권2호
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• pp.169-173
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• 1994

인도네시아 Manado만의 Sulawesi에서 채집한 미동정된 해면으로부터 KB cancer cell line에 대해 활성을 갖는 xestoquinone, halenaquinol sulfate 및 halenaquinol이 검출되었다. 이들을 $^1H-,\;^{13}C$-NMR, $^1H-,\;^{13}C$(1 bond) heteronuclear Multiple Quantum Cogerence Spectroscopy$(HMQC)^1$, $^1H-,\;^{13}C$C(2 and 3 bond) Heteronuclear multiple Bond Correlation Spectroscopy$(HMBC)^2$, Electron Impact Mass Spectroscopy(EI ms), UV 및 IR에 의해 밝혔다.

• KSBB Journal
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• 제27권1호
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• pp.28-32
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• 2012

In this study, the treatment ability of the wastewater containing perchlorate by non-salt tolerant perchlorate reducing bacterial consortium (N-PRBC) was evaluated in a continuous stirred tank bioreactor (CSTR). To obtain the optimal operating condition the bioreactor was operated with the different wastewater empty bed retention time (EBRT). The treatment performance in the bioreactor could be maintained at 100 $mg-ClO_4{^-}L^{-1}$ up to a EBRT of 3 h, and the removal capacity in the CSTR was about 3.3 times higher than that in a batch operation. With a decrease from 9 h to 2 h in a EBRT, the volumetric perchlorate reduction rate was increased from 11.1 $mg-ClO_4{^-}L^{-1}h^{-1}$ to 50.0 $mg-ClO_4{^-}L^{-1}h^{-1}$, and the specific perchlorate reduction rates were increased from 3.01 $mg-ClO_4{^-}g-DCW^{-1}h^{-1}$. In conclusion, the treatment capacities in a CSTR were much better than those obtained in a batch operation.

• Natural Product Sciences
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• 제12권4호
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• pp.237-240
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• 2006

Paeoniflorin, the major component of the root of Paeonia lactiflora, was quantitatively analyzed using $^1H-NMR$ spectrometry. The quantity of paeoniflorin was calculated by the ratio of the intensity of the signals (H-9, H-10, H-2', 6') to the aldehyde peak of the known amount of internal standard, 2,4,6-trihydroxybenzaldehyde. These results were compared with the conventional HPLC method. The contents of paeoniflorin in P. lactiflora, which were respectively calculated by H-9, H-10, H-2', 6' in the $^1H-NMR$ spectra and HPLC, were determined $2.60{\pm}0.07,\;2.44{\pm}0.09,\;2.77{\pm}0.12\;and\;2.46{\pm}0.16%$. The advantages of quantitative $^1H-NMR$ analysis are that can be analyzed to identify and quantify, and no reference compounds required for calibration curves. Besides, it allows rapid and simple quantification for paeoniflorin with an analysis time for only 20 min without any preprocessing.