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101.
Morlière P Haigle J Aissani K Filipe P Silva JN Santus R 《Photochemistry and photobiology》2004,79(2):163-171
The phototoxicity of cyamemazine (CMZ, Tercian), a neuroleptic of the phenothiazine family, has recently been reported in humans. CMZ has an absorbance maximum at 267 nm (molar absorptivity, 25,800 M(-1) cm(-1)) but a weaker molar absorptivity in the ultraviolet A (UV-A) region. CMZ exhibits a fluorescence with maximum emission at 535 nm and a quantum yield of 0.11. CMZ is a powerful photosensitizing agent toward HS 68 human skin fibroblasts and NCTC 2544 keratinocytes. At a UV-A radiation dose of 10 J/cm2, innocuous to cells in the absence of CMZ, the LD50 (lethal dose corresponding to 50% killing) are 0.5 and 1 microM for the fibroblasts and the keratinocytes, respectively, after overnight incubation with the drug. Short incubation times do not significantly alter the LD50. The CMZ-induced phototoxicity is accompanied by lipid membrane peroxidation consistent with the amphiphilic character of this photosensitizer. Keratinocytes are an order of magnitude less sensitive to the photosensitized lipid peroxidation than fibroblasts. Microspectrofluorometry reveals that lysosomal membranes are major sites of CMZ incorporation into the two cell lines because a Forster-type resonance energy transfer process occurs from CMZ to LysoTracker Red DND99 (LTR), a specific fluorescent probe of lysosomal membranes. The CMZ-photosensitized destruction of LTR demonstrates that CMZ retains its photosensitizing capacity after its lysosomal uptake. 相似文献
102.
Syntheses of 5H-[1,2,4]triazolo[5′,1′:2,3][1,3]thiazino[5,4-c]quinolines 8, 5H-[1,2,4]triazolo[3′,4′:2)3][1,3]thiazino[5,4-c]quinolines 9, 5H-[1,2,4]triazolo[5′,1′:2,3][1,3]thiazino[5,6-c]quinolines 14 and 5H-[1,2,4]triazolo[3′,4′:2,3][1,3]thiazino[5,6-c]quinolines 15 are described starting from 4-chloro-3-chloromethylquinaldine (4) and 1,2,4-triazole-5-thiols 5 taking advantage of different reactivity of the chlorine atoms of 4 under different reaction conditions. The structures of products 8, 9, 14 and 15 and the intermediates leading to them were confirmed by desulfurization, unequivocal syntheses and nmr spectroscopy as well. 相似文献
103.
Abrunhosa F Faria S Gomes P Tomaz I Pessoa JC Andreu D Bastos M 《The journal of physical chemistry. B》2005,109(36):17311-17319
The interaction of two hybrid peptides of cecropin A and melittin [CA(1-8)M(1-18) and CA(1-7)M(2-9)] with liposomes was studied by differential scanning calorimetry (DSC), circular dichroism (CD), and quasi-elastic light scattering (QELS). The study was carried out with large unilamellar vesicles (LUVs) of three different lipid compositions: 1,2-dimyristoil-sn-glycero-3-phosphocholine (DMPC), 1,2-dimyristoyl-sn-glycero-3-phospho-rac-(1-glycerol) (DMPG) and a binary mixture of DMPC/DMPG, in a wide range of peptide-to-lipid (P:L) molar ratios (0 to 1:7). DSC results indicate that, for both peptides, the interaction depends on membrane composition, with very different behavior for zwitterionic and anionic membranes. CD data show that, although the two peptides have different secondary structures in buffer (random coil for CA(1-7)M(2-9) and predominantly beta-sheet for CA(1-8)M(1-18)), they both adopt an alpha-helical structure in the presence of the membranes. Overall, results are compatible with a model involving a strong electrostatic surface interaction between the peptides and the negatively charged liposomes, which gives place to aggregation in the gel phase and precipitation after a threshold peptide concentration. In the case of zwitterionic membranes, a progressive surface coverage with peptide molecules destabilizes the membrane, eventually leading to membrane disruption. Moreover, delicate modulations in behavior were observed depending on the peptide. 相似文献
104.
In this work a simple, fast, sensitive and selective flow-based procedure for the chemiluminometric determination of carvedilol, a recent non-cardioselective β-blocker with noteworthy antioxidant activity, is proposed. The developed methodology takes advantage of the antioxidant capacity of carvedilol to inhibit the chemiluminescence response resulting from the oxidation of luminol by hypochlorite, by acting as a hypochlorite scavenger. The analytical process was implemented in a multi-pumping flow system that employs multiple solenoid actuated micro-pumps as the only active components. These acted as solution insertion, propelling and commuting units assuring an easily controlled, low cost, compact and reliable analytical system.A linear working range for carvedilol concentrations ranging from 1.2 × 10−7 to 3.0 × 10−6 mol l−1 (r > 0.999, n = 6), was obtained, with a detection limit of 8.7 × 10−9 mol l−1. The system handles about 65 samples per hour yielding precise results (R.S.D. < 1.3%, n = 10). Recoveries within 95 and 104% were obtained. 相似文献
105.
Nunes CD Valente AA Pillinger M Rocha J Gonçalves IS 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(18):4380-4390
Mo K-edge XAFS spectra have been measured for ordered mesoporous silica MCM-41 grafted with the complexes [MoO2X2(thf)2] (X=Cl, Br). For grafting reactions in the absence of triethylamine, materials with 1 wt. % Mo are obtained; the Mo K-edge EXAFS results indicate the co-existence of isolated surface-fixed monomeric species [MoO2[(-O)3SiO]2(thf)(n)] and [MoO2[(-O)3SiO]X(thf)(n)]. When Et3N is used in the grafting reactions, materials with 4 wt. % Mo are obtained. The EXAFS data for the material prepared using [MoO2Cl2(thf)2] and Et3N indicate the presence of dinuclear species with two Mo(VI) centres, each with two Mo=O groups and each linked by one or two oxo bridges (Mo...Mo 3.27 A). The molybdenum centres in the material prepared using the dibromo complex comprise mainly isolated four-coordinate dioxomolybdenum(VI) and trioxomolybdenum(VI) monomeric species, with a small contribution from dimeric species. All materials were further characterised in the solid state by powder X-ray diffraction, N2 adsorption analysis, MAS NMR (13C, 29Si) and FTIR spectroscopy. The derivatised MCMs perform differently as catalysts in the liquid-phase oxidation of various olefins and alcohols with tert-butyl hydroperoxide. The highest alkene epoxidation activity was recorded for the catalysts with low metal loading, whereas the material containing oxo-bridged dimers had the highest activity for oxidation of alcohols. The recyclability of all the catalysts was tested: the catalytic activity of the derivatised materials tended to stabilize with ageing. 相似文献
106.
The complexes of 4-chloro-2-methoxybenzoic acid anion with Mn2+,
Co2+, Ni2+, Cu2+
and Zn2+ were obtained as polycrystalline solids
with general formula M(C8H6ClO3)2·nH2O and colours typical for M(II) ions (Mn – slightly pink, Co –
pink, Ni – slightly green, Cu – turquoise and Zn – white).
The results of elemental, thermal and spectral analyses suggest that compounds
of Mn(II), Cu(II) and Zn(II) are tetrahydrates whereas those of Co(II) and
Ni(II) are pentahydrates. The carboxylate groups in these complexes are monodentate.
The hydrates of 4-chloro-2-methoxybenzoates of Mn(II), Co(II), Ni(II), Cu(II)
and Zn(II) heated in air to 1273 K are dehydrated in one step in the range
of 323–411 K and form anhydrous salts which next in the range of 433–1212
K are decomposed to the following oxides: Mn3O4,
CoO, NiO and ZnO. The final products of decomposition of Cu(II) complex are
CuO and Cu. The solubility value in water at 293 K for all complexes is in
the order of 10–3 mol dm–3.
The plots of χM
vs.
temperature of 4-chloro-2-methoxybenzoates of Mn(II), Co(II), Ni(II) and Cu(II)
follow the Curie–Weiss law. The magnetic moment values of Mn2+,
Co2+, Ni2+ and Cu2+
ions in these complexes were determined in the range of 76−303 K and
they change from: 5.88–6.04 μB for Mn(C8H6ClO3)2·4H2O, 3.96–4.75
μB for Co(C8H6ClO3)2·5H2O, 2.32–3.02 μB for Ni(C8H6ClO3)2·5H2O and 1.77–1.94
μB for Cu(C8H6ClO3)2·4H2O. 相似文献
107.
Aresta M Tommasi I Quaranta E Fragale C Mascetti J Tranquille M Galan F Fouassier M 《Inorganic chemistry》1996,35(14):4254-4260
Extended labeling experiments have shown that formation of rhodium peroxocarbonate from CO(2) and [RhCl(eta(2)-O(2))(P)(3)] (P is PEt(2)Ph or PEtPh(2)) proceeds through O-O bond cleavage and CO(2) insertion. O-transfer to ancillary phosphine ligand to give R(3)P=O selectively (>85%) involves the Rh-linked O atom of the peroxo group of RhCl(CO(4))(P)(3). 相似文献
108.
The regio- and stereoselective addition of chlorosulfonyl isocyanate to (+)-3-carene 1 resulted in β-lactam 2, which was converted to N-Boc-β-amino acid 4, β-amino ester 7, and carboxamide derivatives 18 and 20 via N-Boc activation and mild ring opening. The corresponding β-amino ester 7 was transformed to 2-thioxopyrimidin-4-one 11 and 2,4-pyrimidinedione 13. LAH reduction of 5 and 7 resulted in amino alcohols 6 and 8. The reaction of 8 with phenyl isothiocyanate, followed by cyclisation, furnished 1,3-oxazine 15. 相似文献
109.
Defoer N De Bo I Van Langenhove H Dewulf J Van Elst T 《Journal of chromatography. A》2002,970(1-2):259-273
The relationship between chemical concentrations (gas chromatography–mass spectrometry analysis) and odour concentrations (olfactometry) was studied for biofilter emissions from four aerobic vegetable, fruit and garden waste (VFG) composting plants and one animal rendering plant. For the VFG composting plants, the study revealed a good linear relationship of the odour concentration with the total volatile organic compounds (VOC) concentration (R2=0.97, n=16) as well as with the concentration of esters and ketones (R2=0.9, n=19). For biofilter emissions of the animal rendering plant, the total VOC concentration was a poor estimator for odour concentration. However, for this type of odour, concentrations of organic sulphur containing compounds correlated well with odour concentrations (R2=0.94, n=8). The results of the study also showed that the relationship between chemical and odour concentrations is specific for each type of odour and cannot be generalized. 相似文献
110.
I. Joó 《Analysis Mathematica》1975,1(4):273-281
В этой работе мы даем о бобщение понятия нор мальной системы точек, введен ного Фейером [3]. Наше определ ение включает и случа й бесконечного интерв ала (0, ∞). Доказано, в частности, что систе ма точек 0<x 1 (n) /(n)<... n (n) <∞ является нормальной в смысле нашего определения тогда и т олько тогда, когда вып олняются оценки — фиксированное чис ло, 0≦?<1. Мы доказываем, что есл и точкиx k (n) /(n) являются ну лями многочлена ЛагерраL n (α) (x), то они образуют норма льную систему в том и т олько том случае, когда ?1<α≦0. Мы получаем, таким обр азом, положительный интерполяционный пр оцесс для каждой нормальной системы т очек и устанавливаем теорему сходимости для того с лучая, когда эти точки являются ну лямиL n (α) (x) при — 1相似文献