Página 1 dos resultados de 61314 itens digitais encontrados em 0.197 segundos

‣ Anti-hepatocellular carcinoma activity using human HepG2 cells and hepatotoxicity of 6-substituted methyl 3-aminothieno[3,2-b]pyridine-2- carboxylate derivatives: In vitro evaluation, cell cycle analysis and QSAR studies

Abreu, Rui M.V.; Ferreira, Isabel C.F.R.; Calhelha, Ricardo C.; Lima, Raquel T.; Vasconcelos, M. Helena; Adega, Filomena; Chaves, Raquel; Queiroz, Maria João R.P.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.56229%
Hepatocellular carcinoma (HCC) is a highly complex cancer, resistant to commonly used treatments and new therapeutic agents are urgently needed. A total of thirty-two thieno[3,2-b]pyridine derivatives of two series: methyl 3-amino- -(hetero)arylthieno[3,2-b]pyridine-2-carboxylates (1ae1t) and methyl 3-amino-6-[(hetero)arylethynyl]thieno[3,2-b]pyridine-2-carboxylates (2ae2n), previously prepared by some of us, were evaluated as new potential anti-HCC agents by studying their in vitro cell growth inhibition on human HepG2 cells and hepatotoxicity using a porcine liver primary cell culture (PLP1). The presence of amino groups linked to a benzene moiety emerges as the key element for the anti-HCC activity. The methyl 3-amino-6-[(3-aminophenyl)ethynyl]thieno[3,2-b]pyridine-2-carboxylate (2f) is the most potent compound presenting GI50 values on HepG2 cells of 1.2 mM compared to 2.9 mM of the positive control ellipticine, with no observed hepatotoxicity (PLP1 GI50 > 125 mM against 3.3 mM of ellipticine). Moreover this compound changes the cell cycle profile of the HepG2 cells, causing a decrease in the % of cells in the S phase and a cell cycle arrest in the G2/M phase. QSAR studies were also performed and the correlations obtained using molecular and 1D descriptors revealed the importance of the presence of amino groups and hydrogen bond donors for anti-HCC activity...

‣ Aminodi(hetero)arylamines in the thieno[3,2-b]pyridine series: synthesis, effects in human tumor cells growth, cell cycle analysis, apoptosis and evaluation of toxicity using non-tumor cells.

Calhelha, Ricardo C.; Ferreira, Isabel C.F.R.; Peixoto, Daniela; Abreu, Rui M.V.; Vale-Silva, Luís A.; Pinto, Eugénia; Lima, Raquel T.; Alvelos, M. Inês; Vasconcelos, M. Helena; Queiroz, Maria João R.P.
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.371616%
Three aminodi(hetero)arylamines were prepared via a palladium-catalyzed C-N Buchwald-Hartwig coupling of methyl 3-aminothieno[3,2-b]pyridine-2-carboxylate with different bromonitrobenzenes, followed by reduction of the nitro groups of the coupling products to the corresponding amino compounds. The aminodi(hetero)arylamines thus obtained were evaluated for their growth inhibitory effect on four human tumor cell lines MCF-7 (breast adenocarcinoma), A375-C5 (melanoma), NCI-H460 (non-small cell lung cancer) and HepG2 (hepatocellular carcinoma). The toxicity to non-tumor cells was also evaluated using a porcine liver primary cell culture (PLP1), established by us. The aminodi(hetero)arylamine with the NH2 group in the ortho position and an OMe group in the para position to the NH of the di(hetero)arylamine, is the most promising compound giving the lowest GI50 values (1.30–1.63 μM) in all the tested human tumor cell lines, presenting no toxicity to PLP1 at those concentrations. The effect of this compound on the cell cycle and induction of apoptosis was analyzed in the NCI-H460 cell line. It was observed that it altered the cell cycle profile causing a decrease in the percentage of cells in the G0/G1 phase and an increase of the apoptosis levels.

‣ 1-Aryl-3-[4-(thieno[3,2-d]pyrimidin-4-yloxy)phenyl]ureas as VEGFR-2 tyrosine kinase inhibitors: Synthesis, biological evaluation, and molecular modelling studies

Soares, Pedro; Costa, Raquel; Froufe, Hugo J.C.; Calhelha, Ricardo C.; Peixoto, Daniela; Abreu, Rui M.V.; Ferreira, Isabel C.F.R.; Soares, Raquel; Queiroz, Maria João R.P.
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
66.445405%
The Vascular Endothelial Growth Factor Receptor-2 (VEGFR-2) is a tyrosine kinase receptor involved in the growth and differentiation of endothelial cells that is implicated in tumor-associated angiogenesis. In this study novel 1-aryl-3-[4-(thieno[3,2-d]pyrimidin-4-yloxy)phenyl]ureas were synthesized and evaluated for the VEGFR-2 tyrosine kinase inhibition. Three of these compounds showed good VEGFR-2 inhibition presenting low IC50 values (150-199 nM) in enzymatic assays. The latter promoted also significant inhibition of cell proliferation at low concentrations (0.5-1 µM), not affecting cell viability, of VEGF-stimulated Human Umbilical Vein Endothelial Cells (HUVECs) using the BrdU assay. The determination of the total and phosphorylated (active) VEGFR-2 was performed by western-blot, and it was possible to conclude that the compounds significantly inhibit the phosphorylation of the receptor at 1 µM pointing to their antiproliferative mechanism of action in HUVECs. The molecular rationale for inhibiting the tyrosine kinase domain of VEGFR-2 was also done and discussed using molecular docking studies.

‣ New di(hetero)arylethers and di(hetero)arylamines in the thieno[3,2-b]pyridine series: Synthesis, growth inhibitory activity on human tumor cell lines and non-tumor cells, effects on cell cycle and on programmed cell death

Queiroz, Maria João R.P.; Peixoto, Daniela; Calhelha, Ricardo C.; Soares, Pedro; Santos, Tiago; Lima, Raquel T.; Campos, Joana F.; Abreu, Rui M.V.; Ferreira, Isabel C.F.R.; Vasconcelos, M. Helena
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.517393%
New fluorinated and methoxylated di(hetero)arylethers and di(hetero)arylamines were prepared functionalizing the 7-position of the thieno[3,2-b]pyridine, using copper (C–O) or palladium (C–N) catalyzed couplings, respectively, of the 7-bromothieno[3,2-b]pyridine, also prepared, with ortho, meta and para fluoro or methoxy phenols and anilines. The compounds obtained were evaluated for their growth inhibitory activity on the human tumor cell lines MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer), HCT15 (colon carcinoma), HepG2 (hepatocellular carcinoma) and HeLa (cervical carcinoma). The most active compounds, a di(hetero)arylether with a methoxy group in the meta position relative to the ether function and two di(hetero)arylamines with a methoxy group either in the ortho or in the meta position relative to the NH, were further tested at their GI50 concentrations on NCI-H460 cells causing pronounced alterations in the cell cycle profile and a strong and significant increase in the programmed death of these cells. The fluorinated and the other methoxylated compounds did not show important activity, presenting high GI50 values in all the cell lines tested. Furthermore, the hepatotoxicity of the compounds was assessed using porcine liver primary cells (PLP2)...

‣ Antioxidant activity of aminodiarylamines in the thieno[3,2-b]pyridine series: radical scavenging activity, lipid peroxidation inhibition and redox profile

Calhelha, Ricardo C.; Peixoto, Daniela; Vilas-Boas, Miguel; Queiroz, Maria João R.P.; Ferreira, Isabel C.F.R.
Fonte: Informa Healthcare Publicador: Informa Healthcare
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.371616%
The antioxidant activity of the aminodi(hetero)arylamines, prepared by C-N coupling of the methyl 3-aminothieno[3,2-b]pyridine-2-carboxylate with bromonitrobenzenes and further reduction of the obtained nitro compounds, was evaluated by chemical, biochemical and electrochemical assays. The aminodi(hetero) arylamine with the amino group ortho to the NH and a methoxy group in para, was the most efficient in radical scavenging activity (RSA, 63 mu M) and reducing power (RP, 33 mu M), while the aminodiarylamine with the amino group in para to the NH, gave the best results in beta-carotene-linoleate system (41 mu M) and inhibition of formation of thiobarbituric acid reactive substances in porcine brain cells homogenates (7 mu M), with EC50 values even lower than those obtained for the standard trolox. This diarylamine also presented the lowest oxidation potential, lower than the one of trolox, and the highest antioxidant power in the electrochemical assays. The para substitution with an amino group enables higher antioxidant potential.

‣ Novel electroluminescent devices containing Eu(3+)-(2-acyl-1,3-indandionate) complexes with TPPO ligand

TEOTONIO, E. E. S.; BRITO, H. F.; CREMONA, M.; QUIRINO, W. G.; LEGNANI, C.; FELINTO, M. C. F. C.
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
56.843594%
Fabrication and electroluminescent properties of devices containing europium complexes of general formula [Eu(ACIND)(3)(TPPO)(2)], where ACIND, 2-acyl-1,3-indandionate ligands: and TPPO, triphenylphosphine oxide. as emitter layers are discussed. The double-layer devices based on these complexes present the following configurations: device 1: ITO/TPD/[Eu(AlND)(3)(TPPO)(2)]/Al: device 2: ITO/TPD/[Eu(ISOV-IND)(3)(TPPO)(2)]/Al and device 3: ITO/TPD/[Eu(BIND)(3)(TPPO)(2)]/Al, where AlND, 2-acetyl-1,3-indandionate; ISOVIND, 2-isovaleryl-1,3-indandionate; and BIND, 2-benzoyl-1,3-indandionate, respectively. These devices exhibited photo and electroluminescent emissions. An important characteristic presented by devices is that their electroluminescent (EL) spectra, in the region of (5)D(0) -> (7)F(J) (J = 0, 1, 2, 3 and 4) transitions of Eu(3+) ion, show profiles that are different from photoluminescent (PL) ones. In addition to narrow bands arising from intraconfigurational-4f(6) transitions, devices 1 and 2 also exhibited a broad band with maximum at around 500 nm which is assigned to electrophosphorescence from the indandionate ligands. On the other hand, EL spectra of device 3 present only narrow bands from (5)D(0) -> (7)F(J) transitions. [Eu(ACIND)(3)(TPPO)(2)] complexes are promising candidates to prepare efficient organic light-emitting devices (OLEDs) when compared with those containing Eu(3+)-complexes of aliphatic beta-diketonate anions. (C) 2009 Elsevier B.V. All rights reserved.; FAPESP; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); FACEPE; FACEPE; RENAMI; RENAMI; CNPq-PRONEX; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

‣ The 2:1 cycloadducts from [3+2] 1,3-dipolar cycloaddition of nitrile oxide and vinylacetic acid. Synthesis and liquid crystal behaviour

Tavares, Aline; Vilela, Guilherme D.; Toldo, Josene; Goncalves, Paulo F. B.; Eccher, Juliana; Bechtold, Ivan H.; Sampaio, Anderson R.; Viscovini, Ronaldo C.; Schneider, Paulo H.; Merlo, Aloir A.
Fonte: TAYLOR & FRANCIS LTD; ABINGDON Publicador: TAYLOR & FRANCIS LTD; ABINGDON
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
76.54525%
Four liquid crystals (LC) 3,7a-bis(4-alkyloxyphenyl)-7,7a-dihydro-6H-isoxazolo[2,3-d][1,2,4]oxadiazol-6-yl)acetic acid (7a-d) were synthesised and the mesomorphic behaviour reported. The LCs were characterised as 2: 1 bisadducts, which were obtained from a double [3+2] 1,3-dipolar cycloaddition. In the first step, the cycloaddition of 4-alkyloxyphenylnitrile oxide (4a-d) and vinylacetic acid (5) gave the initial unobserved 1:1 cycloadducts 2-[3-(4-alkyloxyphenyl)-4,5-dihydroisoxazol-5-yl]acetic acid (6a-d). In the second step, the addition of a second equivalent of 4 to 6 yielded the 2: 1 bisadducts 7a-d without any traces of 6. All compounds 7a-d were unstable during the transition from the mesophase to the isotropic state upon first heating as evidenced by the large peaks in the differential scanning calorimetry traces. Due to the chemical instability of the compounds upon heating, the transition temperature related to the smectic C to smectic A transitions was acquired by means of an image processing method. X-Ray diffraction experiments were also used to analyse the liquid-crystalline phases. A theoretical calculation was performed using density functional theory (DFT) methods at the PBE1PBE/6-311+G(2d,p) level (with solvent effect) in order to get information about the energetic profile of the 2: 1 cycloaddition. DFT studies revealed that the cycloaddition process is controlled by the HOMO(dipolarophile) - LUMO(1...

‣ 3-Aminopyrroles and their application in the synthesis ofpyrrolo[3,2-d]pyrimidine (9-deazapurine) derivatives

Salaheldin, Abdellatif M.; Campos, Ana M. F. Oliveira; Rodrigues, Lígia M.
Fonte: ARKAT USA, Inc. Publicador: ARKAT USA, Inc.
Tipo: Artigo de Revista Científica
Publicado em //2008 Português
Relevância na Pesquisa
76.4291%
3-Aminopyrrole derivatives have been synthesized from 3-anilino-2-cyanoacrylonitrile using Thorpe-Ziegler cyclization. These substituted pyrroles are readily converted into 5H-pyrrolo[3,2- d]pyrimidine (9-deazapurines).; Fundação para a Ciência e Tecnologia (FCT); FEDER

‣ Anti-hepatocellular carcinoma activity using human HepG2 cells and hepatotoxicity of 6-substituted methyl 3-aminothieno[3,2-b]pyridine-2-carboxylate derivatives : in vitro evaluation, cell cycle analysis and QSAR studies

Abreu, Rui M. V.; Ferreira, Isabel C. F. R.; Calhelha, Ricardo C.; Lima, Raquel T.; Vasconcelos, M. Helena; Adega, Filomena; Chaves, Raquel; Queiroz, Maria João R. P.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2011 Português
Relevância na Pesquisa
76.56229%
Hepatocellular carcinoma (HCC) is a highly complex cancer, resistant to commonly used treatments and new therapeutic agents are urgently needed. A total of thirty-two thieno[3,2-b]pyridine derivatives of two series: methyl 3-amino-6-(hetero)arylthieno[3,2-b]pyridine-2-carboxylates (1a-1t) and methyl 3-amino-6-[(hetero)arylethynyl]thieno[3,2-b]pyridine-2-carboxylates (2a-2n), previously prepared by some of us, were evaluated as new potential anti-HCC agents by studying their in vitro cell growth inhibition on human HepG2 cells and hepatotoxicity using a porcine liver primary cell culture (PLP1). The presence of amino groups linked to a benzene moiety emerges as the key element for the anti-HCC activity. The methyl 3-amino-6-[(3-aminophenyl)ethynyl]thieno[3,2-b]pyridine-2-carboxylate (2f) is the most potent compound presenting GI50 values on HepG2 cells of 1.2 μM compared to 2.9 μM of the positive control ellipticine, with no observed hepatotoxicity (PLP1 GI50>125 μM against 3.3 μM of ellipticine). Moreover this compound changes the cell cycle profile of the HepG2 cells, causing a decrease in the % of cells in the S phase and a cell cycle arrest in the G2/M phase. QSAR studies were also performed and the correlations obtained using molecular and 1D descriptors revealed the importance of the presence of amino groups and hydrogen bond donors for anti-HCC activity...

‣ New potential antitumoral di(hetero)arylether derivatives in the thieno[3,2-b]pyridine series : synthesis and fluorescence studies in solution and in nanoliposomes

Queiroz, Maria João R. P.; Dias, Sofia; Peixoto, Daniela; Rodrigues, Ana Rita O.; Oliveira, Andreia D. S.; Coutinho, Paulo J. G.; Silva, Luís A. Vale; Pinto, Eugénia; Castanheira, Elisabete M. S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /06/2012 Português
Relevância na Pesquisa
66.580996%
New fluorescent methoxylated di(hetero)arylethers in the thieno[3,2-b]pyridine series were prepared by a copper-catalyzed Ullmann-type C-O coupling of the methyl 3-amino-6-bromothieno[3,2-b]pyridine-2-carboxylate with ortho, meta and para-methoxyphenols, using N,N-dimethylglycine as the ligand and Cs2CO3 as the base. The compounds obtained were tested for their inhibitory growth activity in three human tumor cell lines MCF-7 (breast adenocarcinoma), A375-C5 (melanoma), NCI-H460 (non-small cell lung cancer). The di(hetero)arylethers bearing a methoxy group in the ortho and meta positions showed very low GI50 values (1.1 - 2.5 µM) in all the three tumor cell lines. Their fluorescence properties in solution and when encapsulated in different nanoliposome formulations, composed either by egg-yolk phosphatidylcholine (Egg-PC), dipalmitoyl phosphatidylcholine (DPPC), dimyristoyl phosphatidylglycerol (DMPG), dioctadecyldimethylammonium bromide (DODAB), distearoyl phosphatidylcholine (DSPC), with or without cholesterol (Ch), or distearoyl phosphatidylethanolamine-(polyethylene glycol)2000 (DSPE-PEG), were studied. All compounds can be carried in the hydrophobic region of the liposome membrane. The liposomes with incorporated compounds are nanometric in size (diameter lower than 150 nm) and have generally low polydispersity.; Fundação para a Ciência e a Tecnologia (FCT) - Bruker Avance III 400-Univ. Minho).; Fundo Europeu de Desenvolvimento Regional (FEDER); Research Centres...

‣ Fluorescence studies of potential antitumoral 6-heteroarylthieno[3,2-b]pyridines in solution and in nanoliposomes

Carvalho, M. Solange D.; Castanheira, Elisabete M. S.; Oliveira, Andreia D. S.; Calhelha, Ricardo C.; Queiroz, Maria João R. P.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em /07/2012 Português
Relevância na Pesquisa
66.338823%
Fluorescence properties of new potential antitumoral 6-heteroarylthieno[3,2-b]pyridines, recently synthesized, were studied in solution and in nanoliposomes of different compositions. The results indicate that these compounds can be transported in the hydrophobic region of the lipid bilayer. The liposomal formulation Egg-PC:Ch:DPPG (7:3:1) is the one with smaller size and lowest polydispersity.; CFUM - PEst-C/FIS/UI0607/2011 (F-COMP-01-0124-FEDER-022711); Fundação para a Ciência e a Tecnologia - SFRH/BD/47052/2008); CQ/UM - PEst-C/QUI/UI0686/2011 (FCOMP-01-0124-FEDER-022716), PTDC/QUI/81238/2006 (FCOMP-01-0124-FEDER-007467); FEDER

‣ Fluorescence studies on new potential antitumoral 1,3-diarylurea derivatives in the thieno[3,2-b]pyridine series encapsulated in magnetoliposomes

Rodrigues, Ana Rita O.; Mendes, Pedro M. F.; Castanheira, Elisabete M. S.; Coutinho, Paulo J. G.; Peixoto, Daniela; Queiroz, Maria João R. P.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em /07/2012 Português
Relevância na Pesquisa
76.38247%
Magnetic nanoparticles of magnetite and of nickel core with silica shell were prepared and either covered with a lipid bilayer or entrapped in liposomes, forming magnetoliposomes. New potential antitumoral 1,3-diarylurea derivatives of thieno[3,2-b]pyridines were then encapsulated in liposomes and magnetoliposomes and their photophysical behavior was investigated.; CFUM (PEst-C/FIS/UI0607/2011) and CQ/UM (PEst-C/QUI/UI0686/2011) and to research projects PTDC/QUI/81238/2006 (FCOMP-01-0124-FEDER-007467), PTDC/QUIQUI/111060/2009 (FCOMP-01-0124-FEDER-015603).; CQ/UM - PEst-C/QUI/UI0686/2011, PTDC/QUI/81238/2006, FCOMP-01-0124-FEDER-007467, PTDC/QUIQUI/111060/2009, FCOMP-01-0124-FEDER-015603; Fundação para a Ciência e a Tecnologia (FCT); FEDER; COMPETE/QREN/EU

‣ Aminodi(hetero)arylamines in the thieno[3,2-b]pyridine series : synthesis, effects in human tumor cells growth, cell cycle analysis, apoptosis and evaluation of toxicity using non-tumor cells

Calhelha, Ricardo C.; Ferreira, Isabel C. F. R.; Peixoto, Daniela; Abreu, Rui M. V.; Silva, L. A. Vale; Pinto, Eugénia; Lima, Raquel T.; Alvelos, Maria I.; Vasconcelos, M. Helena; Queiroz, Maria João R. P.
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 28/03/2012 Português
Relevância na Pesquisa
76.371616%
Three aminodi(hetero)arylamines were prepared via a palladium-catalyzed C-N Buchwald-Hartwig coupling of methyl 3-aminothieno[3,2-b]pyridine-2-carboxylate with different bromonitrobenzenes, followed by reduction of the nitro groups of the coupling products to the corresponding amino compounds. The aminodi(hetero)arylamines thus obtained were evaluated for their growth inhibitory effect on four human tumor cell lines MCF-7 (breast adenocarcinoma), A375-C5 (melanoma), NCI-H460 (non-small cell lung cancer) and HepG2 (hepatocellular carcinoma). The toxicity to non-tumor cells was also evaluated using a porcine liver primary cell culture (PLP1), established by us. The aminodi(hetero)arylamine with the NH2 group in the ortho position and an OMe group in the para position to the NH of the di(hetero)arylamine, is the most promising compound giving the lowest GI50 values (1.30–1.63 μM) in all the tested human tumor cell lines, presenting no toxicity to PLP1 at those concentrations. The effect of this compound on the cell cycle and induction of apoptosis was analyzed in the NCI-H460 cell line. It was observed that it altered the cell cycle profile causing a decrease in the percentage of cells in the G0/G1 phase and an increase of the apoptosis levels.; Foundation for the Science and Technology (FCT–Portugal) for financial support through the NMR Portuguese network (Bruker 400 Avance III-Univ Minho). FCT and FEDER (European Fund for Regional Development) for financial support through the research centers PEst-C/QUI/UI686/2011and PEst-OE/AGR/UI0690/2011...

‣ New 1,3-diarylureas linked by C-C Suzuki coupling to the methyl 3-aminothieno[3,2-b]pyridine-2-carboxylate moiety: synthesis and fluorescence studies in solution and in lipid membranes

Queiroz, Maria João R. P.; Peixoto, Daniela; Rodrigues, Ana Rita O.; Mendes, Pedro M. F.; Costa, Cátia N. C.; Coutinho, Paulo J. G.; Castanheira, Elisabete M. S.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em /03/2013 Português
Relevância na Pesquisa
76.70014%
New six fluorescent 1,3-diarylureas linked by C-C Suzuki coupling to the 6-position of the methyl 3-aminothieno[3,2-b]pyridine-2-carboxylate moiety were prepared by reaction of the amino groups on the ortho or meta positions relative to the C-C bond of the Suzuki coupling products, with different para-substituted arylisocyanates (H, OMe, CN), in high to excellent yields. The fluorescence properties of the 1,3-diarylureas in solution and in lipid membranes of egg-yolk phosphatidylcholine (Egg-PC), dipalmitoyl phosphatidylcholine (DPPC), dipalmitoyl phosphatidylglycerol (DPPG) or dioctadecyldimethylammonium bromide (DODAB), with or without cholesterol (Ch), were studied. The six 1,3-diarylureas have reasonable fluorescence quantum yields in several solvents (between 0.02 and 0.69) and present a moderately solvent sensitive emission, but are not fluorescent in alcohols and water. The compounds bearing the arylurea moiety in the meta position relative to the C-C bond, especially with the OMe and CN substituents, present the better solvatochromic properties. Incorporation of the six compounds in lipid membranes indicates that all the compounds are deeply located in the hydrophobic region of the lipid bilayers, feeling the transition between the rigid gel phase and fluid phases.; To the Foundation for the Science and Technology (FCT...

‣ Fitotoxicidade de novos álcoois e alquenos derivados do 2alfa,4alfa-dimetil-8-oxabiciclo[3.2.1]oct-6-en-3-ona

Barbosa,L. C. A; Maltha,C. R. A; Demuner,A. J; Silva,V. L.; Oliveira,F. M; Borges,E. E. L
Fonte: Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP Publicador: Fundação Editora da Universidade Estadual Paulista Júlio de Mesquita Filho - UNESP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2005 Português
Relevância na Pesquisa
66.4291%
A reação de cicloadição [4+3] entre o furano e o cátion oxialílico, gerado in situ a partir da 2,4-dibromopentan-3-ona, forneceu o 2alfa,4alfa-dimetil-8-oxabiciclo[3.2.1]oct-6-en-3-ona (1). A oxidação catalítica do oxabiciclo 1 com tetróxido de ósmio em presença de peróxido de hidrogênio em excesso levou à formação do acetonídeo 10, a partir do qual foram obtidos os álcoois 2, 11-15, com rendimentos de 23-86%. O tratamento dos álcoois 11-13 com cloreto de tionila, em presença de piridina, resultou nos respectivos alquenos 17 (94%), 18 (89%) e 19 (80%). A atividade herbicida dos compostos foi avaliada sobre o desenvolvimento do sistema radicular de Sorghum bicolor L. e Cucumis sativus L., nas concentrações de 100 e 250 ppm.

‣ 3-Arylisoxazolyl-5-carboxylic acid and 5-(Hydroxymethyl)-3-aryl-2-isoxazoline as molecular platforms for liquid-crystalline materials

Tavares,Aline; Livotto,Paolo R.; Gonçalves,Paulo F. B.; Merlo,Aloir A.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 Português
Relevância na Pesquisa
66.486904%
The synthesis of the molecular platform for liquid-crystalline materials based on 3-arylisoxazolyl-5-carboxylic acid (1) and 5-(hydroxymethyl)-3-aryl-2-isoxazoline (2) is described. The key intermediates 1 and 2 are obtained by [3+2] 1,3-dipolar cycloaddition reaction between an arylnitrile oxide and an acrylic acid and allylic alcohol as the dipolarophile. The liquid crystals (LC) compounds are synthesized through a "molecular elongation strategy" from the initial isoxazolinic core by connecting the arylacetylene moiety obtained from the Sonogashira reaction. Under these conditions, the series of liquid crystals 5a-c, 6, 7a-g and 8a-d have been successfully synthesized in fair to good yields. The final compounds display nematic and smectic liquid-crystalline properties. The structural properties of the series of the liquid crystals has been studied using DFT methods at level B3LYP/6-31G(d,p). The equilibrium geometries in the gas phase are presented and analyzed.

‣ A Comprehensive Approach to the Profiling of the Cooked Meat Carcinogens 2-Amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine and their Metabolites in Human Urine

Gu, Dan; McNaughton, Lynn; LeMaster, David; Lake, Brian G.; Gooderham, Nigel J.; Kadlubar, Fred F.; Turesky, Robert J.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 19/04/2010 Português
Relevância na Pesquisa
56.84007%
A targeted liquid chromatography/tandem mass spectrometry-based metabolomics-type approach, employing a triple stage quadrupole mass spectrometer in the product ion scan and selected reaction monitoring modes, was established to profile 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), and their principal metabolites in urine of omnivores. A mixed-mode reverse phase cation exchange resin enrichment procedure was employed to isolate MeIQx, and its oxidized metabolites, 2-amino-8-(hydroxymethyl)-3-methylimidazo[4,5-f]quinoxaline (8-CH2OH-IQx) and 2-amino-3-methylimidazo[4,5-f]quinoxaline-8-carboxylic acid (IQx-8-COOH), which are produced by cytochrome P450 1A2 (P450 1A2). The phase II conjugates N2-(ß-1-glucosiduronyl)-2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline and N2-(3,8-dimethylimidazo[4,5-f]quinoxalin-2-yl)-sulfamic acid were measured indirectly, following acid hydrolysis to form MeIQx. The enrichment procedure permitted the simultaneous analysis of PhIP; N2-(ß-1-glucosidurony1)-2-amino-1-methy1-6-phenylimidazo[4,5-b]pyridine; N3-(ß-1-glucosidurony1)-2-amino-1-methy1-6-phenylimidazo[4,5-b]pyridine; 2-amino-1-methyl-6-(4′-hydroxy)-phenylimidazo[4,5-b]pyridine (4′-HOPhIP); and the isomeric N2- and N3-glucuronide conjugates of the carcinogenic metabolite...

‣ Comparison of the pharmacokinetics, biodistribution and dosimetry of monoclonal antibodies OC125, OV-TL 3, and 139H2 as IgG and F(ab')2 fragments in experimental ovarian cancer.

Molthoff, C. F.; Pinedo, H. M.; Schlüper, H. M.; Nijman, H. W.; Boven, E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1992 Português
Relevância na Pesquisa
56.88602%
Monoclonal antibody (MAb) 139H2 was previously shown to localise specifically into ovarian cancer xenografts in nude mice. MAb 139H2 was compared with MAbs OC125 and OV-TL 3, all reactive with ovarian carcinomas, for the binding characteristics as IgG and F(ab')2 fragments with the use of the OVCAR-3 cell line grown in vitro and as s.c. xenografts. Immunoperoxidase staining of OVCAR-3 tissue sections with MAbs OC125 and 139H2 was heterogeneous, whereas MAb OV-TL 3 showed homogeneity. No differences in binding were observed between IgG and F(ab')2. The avidity expressed as apparent affinity constants of MAbs OC125, OV-TL 3 and 139H2 for OVAR-3 cells were 1 x 10(9) M-1, 1 x 10(9) M-1, and 1 x 10(8) M-1, while the number of antigenic determinants were 5 x 10(6), 1 x 10(6) and 7 x 10(6), respectively. In OVCAR-3 bearing nude mice the blood half-lives of the MAbs as IgG and F(ab')2 were approximately 50 h and 6 h, respectively. Maximum tumour uptake for the whole MAbs OC125, OV-TL 3, 139H2 and a control MAb 2C7 was 8.5%, 17.7%, 11.1% and 2.5% of the injected dose g-1, reached at 72 h after injection. For the respective F(ab')2 fragments, the maximum values were 5.2%, 10.0%, 5.5% and 1.9% of the injected dose g-1, reached between 6 h and 15 h. Tumour to non-tumour ratios were more favourable for the F(ab')2 fragments as compared to those for MAbs as IgG. Biodistribution in mice bearing a control tumour confirmed the specificity of tumour localisation of MAbs OC125...

‣ XMM-Newton and Chandra observations of G272.2-3.2. Evidence of stellar ejecta in the central region

Sánchez Ayaso, E.; Combi, Jorge Ariel; Bocchino, F.; Albacete Colombo, Juan Facundo; López-santiago, J.; Martí, J.; Castro, E.
Fonte: Edp Sciences Publicador: Edp Sciences
Tipo: info:eu-repo/semantics/article; info:ar-repo/semantics/artículo; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Português
Relevância na Pesquisa
76.51824%
Aims. We aim to study the spatial distribution of the physical and chemical properties of the X-ray emitting plasma of the supernova remnant G272.2−3.2 in order to obtain important constraints on its ionization stage, the progenitor supernova explosion, and the age of the remnant. Methods. We report on combined XMM-Newton and Chandra images, median photon energy maps, silicon and sulfur equivalent width maps, and a spatially resolved spectral analysis for a set of regions of the remnant. Complementary radio and Hα observations, available in the literature, are also used to study the multi-wavelength connection of all detected emissions. Results. The X-ray morphology of the remnant displays an overall structure with an almost circular appearance and a centrally brightened hard region with a peculiar elongated hard structure oriented along the northwest-southeast direction of the central part. The X-ray spectral study of the regions shows distinct Kα emission-line features of metal elements, confirming the thermal origin of the emission. The X-ray spectra are well represented by an absorbed variable abundance non-equilibrium ionization thermal plasma model, which produces elevated abundances of Si, S, and Fe in the circular central region...

‣ Abstract Certification of Global Non-Interference in Rewriting Logic

Alba-Castro, Mauricio; Alpuente, María; Escobar, Santiago
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 22/06/2010 Português
Relevância na Pesquisa
66.41919%
Non-interference is a semantic program property that assigns confidentiality levels to data objects and prevents illicit information flows from occurring from high to low security levels. In this paper, we present a novel security model for global non-interference which approximates non-interference as a safety property. We also propose a certification technique for global non-interference of complete Java classes based on rewriting logic, a very general logical and semantic framework that is efficiently implemented in the high-level programming language Maude. Starting from an existing Java semantics specification written in Maude, we develop an extended, information-flow Java semantics that allows us to correctly observe global non-interference policies. In order to achieve a finite state transition system, we develop an abstract Java semantics that we use for secure and effective non-interference Java analysis. The analysis produces certificates that are independently checkable and are small enough to be used in practice.; Comment: 26 pages. ACM class (full): D.2.4 [Software Engineering]: Software/Program Verification---Formal Methods; F.3.2 [Logics and Meaning of Programs]: Semantics of Programming Languages---Program Analysis