• 대한화학회지
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• 제21권1호
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• pp.3-15
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• 1977

Salicylaldehyde-4-morpholinothiosemicarbazone, $C_{12}H_{15}O_2N_3S$, 결정은 직각비등축정계에 속하며 공간군은 $Pna2_1$이다. 단위세포에는 4개의 분자가 포함되면 세포 길이는 a = 11.85(5), b = 15.45(5), c = 7.18(3)${\AA}$이다. 농도는 multiple-film equi-inclination Weissenberg 사진으로부터 3차원적 농도 데이타를 얻어 목측법에 의하여 측정하였다. 결정구조는 Patterson 및 Fourier법으로 해명하였으며 구조의 정밀화는 block-diagonal 최소자승법으로 하였으며 R값은 1064개의 반사에 대하여 0.11이었다. 몰포린 고리는 의자형이며 1분자내의 몰포린 고리와 황원자를 제외한 원자들은 대략 한 평면을 이룬다. 수산화기의 산소원자는 질소원자와 2.67${\AA}$의 거리로 $O-H{\cdot}{\cdot}{\cdot}N$형 수소결합을 하고 있고 분자간에는 van der Waals 접촉으로 연결되어 있다.

• Journal of applied mathematics & informatics
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• 제15권1_2호
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• pp.457-466
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• 2004

Let{$X_{ni}$\mid$\;1\;{\leq}\;i\;{\leq}\;k_n,\;n\;{\geq}\;1$} be an array of rowwise negatively associated random variables such that $P$\mid$X_{ni}$\mid$\;>\;x)\;=\;O(1)P($\mid$X$\mid$\;>\;x)$ for all $x\;{\geq}\;0,\;and\; \{k_n\}\;and\;\{r_n\}$ be two sequences such that $r_n\;{\geq}\;b_1n^r,\;k_n\;{\leq}\;b_2n^k$ for some $b_1,\;b_2,\;r,\;k\;>\;0$. Then it is shown that $\frac{1}{r_n}\;max_1$\mid${\Sigma_{i=1}}^j\;X_{ni}$\mid$\;{\rightarrow}\;0$ completely convergence and the strong convergence for weighted sums of N A arrays is also considered.

• Bulletin of the Korean Chemical Society
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• 제15권10호
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• pp.857-860
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• 1994

We have calculated the ${\pi}$-electron density, atom self-polarizability, and free valence on each atom of N-(2-chlorobenzyl)-pyridinium, N-(benzyl)-2-chloropyridinium, and N-(2-chlorobenzyl)-2-chloropyridinium salts using a simple Huckel method in order to discuss their intramolecular photocyclization reaction in a qualitative method. Our calculation qualitatively predicts that photocyclization occurs through forming radicals as a reaction intermediate by breaking a C-Cl bond after photoexcitation into a triplet state via intersystem crossing from an initially excited singlet state. We noticed that this C-Cl bond breaking is aided by ${\pi}$-complex formation between a chlorine atom and the ${\pi}$ -electrons of the neighboring ring in the triplet state and a stronger ${\pi}$-complex bond makes C-Cl bond breaking, i.e., radical formation, much easier. A chlorine atom will form a stronger ${\pi}$ -complex bond to a benzyl ring of N-(benzyl)-2-chloropyridinium than a pyridinium ring of N-(2-chlorobenzyl)-pyridinium because the former can donate its ${\pi}$-electron more easily than the latter. The chlorine at position 15 of N-(2-chlorobenzyl)-2-chloropyridinium salt in the excited state also provides its ${\pi}$-electron to the benzyl ring. So this ${\pi}$-electron can increase the bond strength of the $\pi-complex.$ Therefore, the strength of ${\pi}$-complex follows the order of N-(2-chlorobenzyl)-2-chloropyridinium, N-(benzyl)-2-chloropyridinium, and N-(2-chlorobenzyl)-pyridinium salts and thus the radical formation rate. This provides us with an intramolecular photocyclization reaction rate of the same order as given above.

• Natural Product Sciences
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• 제2권2호
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• pp.130-136
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• 1996

Evaluation of plant extracts that might inhibit hepatitis B virus (HBV) replication was performed to find potent anti-HBV agents. Eighty-five species of plants from forty-three families were tested for their anti-HBV activities using HBV-producing HepG2-derived 2.2.15 cells. The anti-HBV activity of plant extracts was measured by slot blot hybridization technique and cytotoxicity was determined by crystal violet staining procedure. All plants were extracted with methanol and the extracts were partitioned into n-hexane, ethyl acetate and aqueous layer. The ethyl acetate fractions of Rhus verniciflua $(stem:\;EC_{50},\;8.2{\mu}g/ml;\;CC_{50},\;9.4{\mu}g/ml)$, Gastrodia elata $(root:\;EC_{50},\;17.7{\mu}g/ml;\;CC_{50},\;>20{\mu}g/ml)$, Raphanus sativus $(seeds:\;EC_{50},\;17.3{\mu}g/ml;\;CC_{50},\;>20{\mu}g/ml)$, and Angelica gigas $(root:\;EC_{50},\;8.3{\mu}g/ml;\;CC_{50},\;15.6{\mu}g/ml)$ revealed the anti-HBV activity in 2.2.15 cell culture system and these fractions are under the process of further sequential fractionation by column chromatography to find the active principles against HBV.

• 한국토양비료학회지
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• 제34권4호
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• pp.284-291
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• 2001

유기질비료와 화학비료 시용에 따른 작물체의 질소동위원소비 (${\delta}^{15}N$) 차이 유무를 조사하기 위해 포트 조건에서 돈분 퇴비 (+13.9‰) 와 요소(-2.3‰) 를 시용하여 70일간 재배한 옥수수의 뿌리, 줄기, 잎, 알곡에 대한 ${\delta}^{15}N$ 값을 분석하였고, 동위원소 질량수지 방정식을 이용하여 옥수수 전부위에 대한 ${\delta}^{15}N$ 값을 계산하였다. 옥수수의 ${\delta}^{15}N$값은 토양 질소의 영향과 질소의 형태변환과정에 수반되는 동위원소분할효과에 의해 시용한 퇴비와 요소의 ${\delta}^{15}N$ 값과 차이를 보였다. 옥수수 전부위, 뿌리 및 줄기의 ${\delta}^{15}N$ 값은 요소와 퇴비 시용에 따른 유의성 있는 차이 (p<0.05)를 나타내지 않았지만, 잎과 알곡의 ${\delta}^{15}N$ 값은 각각 퇴비 처리구(+14.3‰, +16.2‰) > 무처리구(+13.2‰, +13.9‰) > 요소-퇴비 혼합처리구(+10.1‰, +12.6‰) 요소 처리구 (+10.1‰, +12.4‰)의 순서로 유의성 있는 차이가 나타났다. 따라서, 본 연구는 시용 질소원의 종류(퇴비 또는 화학비료)를 확인하는데 있어서 작물의 잎 또는 알곡의 ${\delta}^{15}N$ 값 활용 가능성을 제시해주는 것으로 판단되었다. 하지만, 보다 일반적인 결론을 얻기 위해서는 다양한 종류의 토양과 작물에 대한 연구가 요구된다.

• Journal of Applied Biological Chemistry
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• 제44권3호
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• pp.135-139
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• 2001

To observe the changes in isotopic composition (${\delta}^{15}N$) of $NO_3{^-}$ during denitrification, an incubation experiment using soil treated with nitrification inhibitor (2-chloro-6-trichloromethyl-pyridine) under water-saturated condition was conducted for 153 h. The $NO_3-N$ concentration decreased from 73.3 to $20.6mg\;kg^{-1}$ during the incubation period, with denitrification rate constant of $0.00905h^{-1}$, and ${\delta}^{15}N$ values of $NO_3-N$ increased from +0.9 to +25.5‰ with decreasing the $NO_3-N$ concentration. The increase in the ${\delta}^{15}N$ values of $NO_3-N$ is due to kinetic isotope fractionation, which always results in $^{15}N$ enrichment of the substrate. The isotopic fractionation factor calculated in this study was 1.0196, an indication that 1.96% more $^{14}NO_3{^-}$ reacted at a given time interval than a comparable number of $^{15}NO_3{^-}$. The ${\delta}^{15}N$ values measured through the incubation study showed a good agreement with the results calculated from the Fochts isotope fractionation model. Our results suggest that when the ${\delta}^{15}N$ of $NO_3{^-}$ is used for tracing the fate of N, the kinetic isotope fractionation associated with denitrification must be taken into consideration.

• 생명과학회지
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• 제20권5호
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• pp.676-682
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• 2010

본 연구는 임상검체만이 아닌 주변 생활환경에도 광범위 베타 락탐분해효소를 생성하는 균주(extended-spectrum $\beta$-lactamase, ESBL)가 존재하는지를 확인하고 만약 존재할 경우 그 균주를 분리하고 ESBL유형을 알아보기 위하여 실시되었다. 부산 광안리 하수처리 방류수에서 이중 디스크 확산 검사 결과 양성반응을 나타낸 29균주를 선별하였다. 이중 sodium azide에 내성을 가진 피전달 균주인 Escherichia coli J5에 교차접합이 이루어진 15균주를 대상으로 indole, methyl-red, Voges-Proskauer, Simmon's citrate 시험과 decarboxylase-dihydrolase 및 여러 종류의 당 발효 시험 등 생화학 검사를 실시한 결과 Klebsiella pneumoniae(13균주)와 Escherichia coli(2균주)가 동정되었다. 등전점, PCR, 유전자서열 분석을 실시하여 ESBL 유형을 결정하였다. Klebsiella pneumoniae의 ESBL 생성유형은 SHV-12(4균주)와 SHV-12/TEM-1(9균주)의 2종류로 구분되었고, Escherichia coli의 ESBL 생성유형은 TEM-1(2균주)로 판명되었다.

• Bulletin of the Korean Chemical Society
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• 제26권2호
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• pp.278-280
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• 2005

To obtain cytochrome $c_3$ labeled with a stable isotope, the conditions of cultivation and the composition of medium for DvMF were examined. The growth of DvMF was steady and reproducible under purging with $N_2$ and under pH control. DvMF was able to go on a defined medium without natural products. The composition of medium containing a small amount of $NH_4C$l as sole nitrogen source was established. Then, uniformly $^{15}N$labeled cytochrome $c_3$ was obtained during the culture of DvMF in a defined medium with $^{15}NH_4$Cl; it was confirmed by $^1H-^{15}N$ HMQC.

• BMB Reports
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• 제33권6호
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• pp.506-509
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• 2000

To obtain Cytochrome $c_3$ labeled with a stable isotope, the conditions of cultivation and the composition of medium for DvMF were examined. The growth of DvMF was steady and reproducible under purging with $N_2$ and under pH control. DvMF was able to go on a defined medium without natural products. The composition of the medium containing a small amount of $NH_4Cl$ as sole nitrogen source was established. Then, uniformly $^{15}N-labeled$ Cytochrome $c_3$ was obtained during the culture of DvMF in a defined medium with $^{15}NH_4Cl$; it was confirmed by $^{1}H-^{15}N$ HMQC.

• Natural Product Sciences
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• 제20권2호
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• pp.86-90
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• 2014

Phytochemical investigation of the 80% MeOH extract from the leaves of Hosta longipes resulted in the isolation of sixteen compounds (1 - 16). The structures of the compounds were elucidated by spectroscopic methods to be methyl 10,10-dimethoxydecanoate (1), methyl 10-hydroxy-8E,12Z-octadecadienoate (2), methyl coriolate (3), trans-phytol (4), phytene-1,2-diol (5), phyton (6), (3S,5R,6S,7E,9R)-7-megastigmene-3,6,9-triol (7), (3S,5R,6S,9R)-3,6,9-trihydroxymegastigman-7-ene (8), shikimic acid (9), p-coumaramide (10), trans-N-p-coumaroyltyramine (11), cis-N-coumaroyltyramine (12), tryptophan (13), thymidine (14), adenosine (15), and deoxyadenosine (16). Compound 1 was synthesized, but not yet isolated from natural source, and compounds 2-16 were isolated for the first time from this plant source.