• 제목/요약/키워드: $a_n=a_{n-1}+a_{n-3}$

검색결과 25,696건 처리시간 0.068초

Synthesis and Antitumor Evaluation of Acyclic 1-[${\omega}$-(N^I-2-chloroethyl-N^I-nitrosoureido)alkyl]thymidine Nucleoside Analogues

  • Kim, Jack-C.;Kim, Young-Hyun;Park, Jin-Il;Kim, Seon-Hee;Choi, Soon-Kyu
    • Archives of Pharmacal Research
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    • 제20권3호
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    • pp.259-263
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    • 1997
  • In the preparation of acyclic thymidine nucleoside analogues, $K_2CO_3$(or NaH) treated thymine in DMSO was alkylated with .omega.-chloroalkyl nitrite (Cl-(CH_2)n-CN; n=1, 2, 3, 4) to provide an isomeric mixture of 1-(${\omega}$-cyanoalkyl)thymine (2a-d) and 1,3-bis(${\omega}$-cyanoalkyl)thymine in approximately 5:1 ratios. Reduction of the cyano function 2a-d with $NaBH_{4}/CoCl_{2}$ center dot$ 6H_{2}O$gave the corresponding 1-(${\omega}$aminoalkyl)thymine (3a-d). The newly formed primary amino function in 3a-d was directly reacted with 2-chloroethylisocyanate to afford the 1-[.omega.($N^{I}$-2-chloroethylureido) alkyl]thymine (4a-d) in good yields. Nitrosation of 1-[5-($ N^{I}-2$-chloroethylureido)pentyl] thymine (4d) with glacial acetic acid and dry $NaNO_{2}$-powder in anhydrous $CH_{2}Cl_{2}$gave two types of regioisomeric nitrosoureas, 1-[5-($N^{I}$--chloroethyl-$N^{I}$--nitrosoureido)pentylithymine (5d) and 1-[5-($N^{I}-2$-chloroethyl-N-nitrosoureido)pentyllthymine in approximately 5 :1 ratios. The in vitro cytotoxicity of the synthesized compounds (2a-d, 3a-d, 4a-d and 5a-d) against three cell lines (K-562, P-388 and FM-3A) are measured as $IC^{50}$ values. Compounds 3b and 4c showed moderate activities against all three cell lines, and all other compounds were found to be not active.

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인공 DNase의 리간드 화합물로써 2,9-(N,N-Dimethylethylenediaminomethyl)-1,10-phenanthroline 분자내 수소결합들의 역할 (The Roles of Hydrogen Bonds in 2,9-(N,N-Dimethylethylenediaminomethyl)-1,10-phenanthroline Molecule as a New Ligand Compound of Artificial DNase)

  • 성낙도;박경용
    • Applied Biological Chemistry
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    • 제48권4호
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    • pp.326-330
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    • 2005
  • 인공 DNase의 새로운 리간드 분자로 설계된 2,9-(N,N-dimethylethylenediamino)-1,10-phenanthroline(A) 및 2,9-(N,N-Dimethylethylenediaminomethyl)-1,10-phenanthroline(B)의 Cu(II) 착 화합물에 의한 2',3'-cAMP의 촉매 가수분해 반응에서 리간드 분자의 아미노기들과 2',3'-cAMP의 인산기 사이에 형성되는 분자내 4개의 수소결합들로 인하여 (A) 및 (B)의 Cu(II) 착 화합물은 2,9-dimethyl-o-phenanthroline의 Cu(II) 착 화합물에 의한 2',3'-cAMP의 촉매 가수분해 반응 속도를 7만배 이상 빠르게 촉진 할 것으로 예측되었다.

IDEMPOTENCE PRESERVING MAPS ON SPACES OF TRIANGULAR MATRICES

  • Sheng, Yu-Qiu;Zheng, Bao-Dong;Zhang, Xian
    • Journal of applied mathematics & informatics
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    • 제25권1_2호
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    • pp.17-33
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    • 2007
  • Suppose F is an arbitrary field. Let ${\mid}F{\mid}$ be the number of the elements of F. Let $T_{n}(F)$ be the space of all $n{\times}n$ upper-triangular matrices over F. A map ${\Psi}\;:\;T_{n}(F)\;{\rightarrow}\;T_{n}(F)$ is said to preserve idempotence if $A-{\lambda}B$ is idempotent if and only if ${\Psi}(A)-{\lambda}{\Psi}(B)$ is idempotent for any $A,\;B\;{\in}\;T_{n}(F)$ and ${\lambda}\;{\in}\;F$. It is shown that: when the characteristic of F is not 2, ${\mid}F{\mid}\;>\;3$ and $n\;{\geq}\;3,\;{\Psi}\;:\;T_{n}(F)\;{\rightarrow}\;T_{n}(F)$ is a map preserving idempotence if and only if there exists an invertible matrix $P\;{\in}\;T_{n}(F)$ such that either ${\Phi}(A)\;=\;PAP^{-1}$ for every $A\;{\in}\;T_{n}(F)\;or\;{\Psi}(A)=PJA^{t}JP^{-1}$ for every $P\;{\in}\;T_{n}(F)$, where $J\;=\;{\sum}^{n}_{i-1}\;E_{i,n+1-i}\;and\;E_{ij}$ is the matrix with 1 in the (i,j)th entry and 0 elsewhere.

Carbon and Nitrogen Responses of Litterfall Components by NPK and PK Fertilizers in a Red Pine (Pinus densiflora S. et Z.) Stand

  • Park, Seong-Wan;Baek, Gyeongwon;Kim, Seongjun;Yang, A-Ram;Kim, Choonsig
    • 한국산림과학회지
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    • 제108권1호
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    • pp.21-28
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    • 2019
  • This study was conducted to determine the carbon (C) and nitrogen (N) response of litterfall components as affected by N addition in compound fertilizer in a Korean red pine (Pinus densiflora S. et Z.) stand in southern Korea. Litterfall in a mature red pine stand was collected for two years following compound fertilizer application ($N_3P_4K_1$; $P_4K_1$) and no fertilization (control). The C concentration of litterfall components was not significantly (P > 0.05) different between the $N_3P_4K_1$ and the control plots, whereas the N concentration of the litterfall components was significantly higher in the $N_3P_4K_1$ plot than in the control plot. The $N_3P_4K_1$ and $P_4K_1$ additions induced a lower C/N ratio of litterfall components compared with the control plot. Annual C and N fluxes via litterfall components were not affected by the $N_3P_4K_1$ addition over the study period, except for reproduction litter. Annual N fluxes via reproduction litter were significantly higher in the $N_3P_4K_1$ plot than in the control plot. Thus, the $N_3P_4K_1$ and $P_4K_1$ additions could modify differently nutrient distribution of the forest floor and mineral soils in a red pine stand. These results indicate that N concentration and C/N ratio in litterfall components are more susceptible to fertilizer application than the C response in litterfall components.

한국산 도꼬마리 추출물로부터 항균.항암물질의 탐색 (Screening of the Antimicrobial and Antitumor Activity of Xanthium strumarium L.Extract)

  • 김현수;유대식;이인선;김용원;여수환
    • KSBB Journal
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    • 제18권1호
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    • pp.55-61
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    • 2003
  • 항균 및 항암성 물질을 탐색하기 위하여 도꼬마리 열수 추출액을 ether 및 ethylacetate를 이용하여 중성, 산성, 염기성조건에서 추출한 후, 각각의 추출물을 세균 16균주 및 곰팡이와 효모 2균주를 대상으로 항균활성을 조사하였다. Ether 중성 추출물(XE-N)은 항균효과가 가장 우수하였으며, 특히 그람 양성세균(7균주), 그람 음성세균(7균주)을 비롯하여 진균중 Cryptococcus neoformans에도 뚜렷한 항균효과를 나타내었다. XE-N 및 XEA-N을 대상으로 FDA method에 의한 항균효과를 검토한 결과, p. aeruginosa를 제외한 3균주에 대해 30 ng/mL에서도 저해효과를 나타내었다 XE-N으로부터 XE-N-S1, XE-N-S3을, Ether 산성 추출물(XE-A)로부터 XE-N-S3 을, ethylacetate 중성 추출물(XEA-N)로부터 XEA-N-S2를 항균, 항암성 물질로 정제하였으나, XE-N-S1을 제외한 다른 물질들은 빠른 시간 내에 모두 분해되었다 도꼬마리 추출물 및 정제된 생리활성물질에 대한 항암효과를 검토한 결과, HeLa 자궁암 세포에 대해서는 XE-N-S1이 가장 우수하였다. HepG2간암세포에 대한 항암효과는 XE-N-S, XE-N-S3가 우수하였고, HT29 대장암세포에 대한 항암효과는 XE-N, XE-N-S1이 우수하였다. Saos2 골육종 암세포, NCI H522 폐선 암세포, NCI H1703 폐 편평세포 암세포와 Clone M3 흑색종 암세포에 대한 항암효과는 XE-N-S1이 가장 우수하였다. LN CAP 전립선 암세포에 대한 항암효과는 XE-N-S3가 가장 우수한 효과를 나타내었다. 또한 HSF 인간 정상 피부 섬유아세포에 대한 각종 추출물 및 정제물의 세포독성을 기존의 항암제인 etoposide와 cisplatin과 비교·검토한 결과, XE-A, XEA-A 및 XEA-B가 가장 독성이 낮았으며, XE-B도 etoposide에 비해 독성이 낮았다. 한편 XE-N-S1, XE-N-S3은 etoposide보다 높은 독성을 나타내었으며, XE-A-S3은 etoposide보다는 독성이 높았으나, cisplatin보다는 낮았다.

Reaction of Ru(tpy)$Cl_3$ with N,N,C-Terdentates, 3,2'-Annulated-6-(2"-pyridyl)-2-phenylpyridines

  • 장영동;박재규
    • Bulletin of the Korean Chemical Society
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    • 제20권10호
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    • pp.1200-1204
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    • 1999
  • The reactions of Ru(tpy)Cl3 (tpy = 2,2';6',2"-terpyridine) with new N,N,C-terdentate ligands, 3,2'-annulated-6-(2"-pyridyl)-2-phenylpyridines (1, HL) and the properties of their Ru(II) complexes are described. The distribution ratio of the two possible Ru(II) complexes, a pentaaza-coordinated complex [Ru(tpy)(1-N,N')Cl]+ and a cycloruthenated complex [Ru(tpy)(La-N,N',C)]+ are highly dependent on the length of the polymethylene unit. The trimethylene bridge of the N,N,C-terdentate in pentaaza-coordinated complex is rigid enough to induce an asymmetry in the complex.

$N^4$-furoylsulfanamide류의 합성및 항균작용에 관한 연구 (Studies on the synthesis and antibacterial action of $N^4$-furoylsulfonamides)

  • 고현기
    • 약학회지
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    • 제13권2_3호
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    • pp.62-66
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    • 1969
  • Ten new N$^{4}$-furoylsulfonamides were synthesized such as N$^{4}$-furoyl-N$^{1}$-(4,6-dimethyl-2-pyrimidinyl) sulfanilamide (I), N$^{4}$-furoylsulfanilamide (II), N$^{4}$-furoyl-N$^{1}$-(2,6-dimethoxy-4-pyrimidinyl) sulfanilamide (III), N$^{4}$-furoyl-N$^{1}$-(4-methyl-2-pyrimidinyl) sulfanilamide (IV), N$^{4}$-furoyl-N$^{1}$-(6-methoxy-3-pyridazinyl) sulfanilamide (V), N$^{4}$-furoyl-N$^{1}$-2-pyrimidinylsulfanilamide (VI), N$^{4}$-furoyl-N$^{1}$-(3,4-dimethyl-5-isoxazolyl) sulfanilamide (VII), N$^{4}$-furoyl-N$^{1}$-2-thiazoilysulfanilamide (VIII), N$^{4}$-furoyl-N$^{1}$-(5-methoxy-2-pyrimidinyl) sulfanilamide (IX) and N$^{4}$-furoyl-N$^{1}$-(2,6-dimethyl-4-pyrimidinyl) sulfanilamide (X). They were obtained by the action of N$^{1}$-(4,6-dimethyl-2-pyrimidinyl) sulfanilamide, N$^{1}$-(2,6-dimethoxy-4-pyrimidinyl) sulfanilamide, N$^{1}$-(4-methyl-2-pyrimidinyl) sulfanilamide, N$^{1}$-(6-methoxy-3-pyridazinyl) sulfanilamide, N-2-pyrimidinyl sulfanilamide, N$^{1}$-(3,4-dimethyl-5-isoxazolyl) sulfanilamide, N$^{1}$-2-(thiazolysulfanilamide), N$^{1}$-(5-methoxy-2-pyrimidinyl) sulfanilamide and N$^{1}$-(2,6-dimethyl-4-pyrimidinyl) sulfanilamide with furoyl chloride in 4% NaOH solution. Of the above ten compounds, N$^{4}$-furoylsulfathiazole exhibited a good antibacterial action against Staphylococeus aureus and Escherichia coli.

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THE RELATION PROPERTY BETWEEN THE DIVISOR FUNCTION AND INFINITE PRODUCT SUMS

  • Kim, Aeran
    • 호남수학학술지
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    • 제38권3호
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    • pp.507-552
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    • 2016
  • For a complex number q and a divisor function ${\sigma}_1(n)$ we define $$C(q):=q{\prod_{n=1}^{\infty}}(1-q^n)^{16}(1-q^{2n})^4,\\D(q):=q^2{\prod_{n=1}^{\infty}}(1-q^n)^8(1-q^{2n})^4(1-q^{4n})^8,\\L(q):=1-24{\sum_{n=1}^{\infty}}{\sigma}_1(n)q^n$$ moreover we obtain the number of representations of $n{\in}{\mathbb{N}}$ as sum of 24 squares, which are possible for us to deduce $L(q^4)C(q)$ and $L(q^4)D(q)$.

NONBINARY INCIDENCE CODES OF (n, n − 1, j)-POSET

  • Yan, Longhe
    • Korean Journal of Mathematics
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    • 제17권2호
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    • pp.169-179
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    • 2009
  • Let P be a (n, n − 1, j)-poset, which is a partially ordered set of cardinality n with n − 1 maximal elements and $j(1{\leq}j{\leq}n-1)$ minimal elements, and $P^*$ the dual poset of P. In this paper, we obtain two types of incidence codes of nonempty proper subset S of P and $P^*$, respectively, by using Bogart's method [1] (see Theorem 3.3).

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THE LINEAR DISCREPANCY OF 3 × 3 × 3

  • Chae, Gab-Byoung;Cheong, Min-Seok;Kim, Sang-Mok
    • 대한수학회논문집
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    • 제25권1호
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    • pp.19-25
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    • 2010
  • $3{\times}3{\times}3$ is the meaningful smallest product of three chains of each size 2n+1 since $1{\times}1{\times}1$ is a 1-element poset. The linear discrepancy of the product of three chains $2n{\times}2n{\times}2n$ is found as $6n^3-2n^2-1$. But the case of the product of three chains $(2n + 1){\times}(2n + 1){\times}(2n + 1)$ is not known yet. In this paper, we determine ld$(3{\times}3{\times}3)$ as a case to determine the linear discrepancy of the product of three chains of each size 2n + 1.