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71.
Peptidoglycan is a widespread bacterial PAMP molecule and a powerful initiator of innate immune responses. It consists of repeating units of MDP, which as a monomer is only weakly immunostimulatory. Here, MDP-coupled dendrimers were prepared and investigated for stimulation of pig blood mononuclear cells. Compared to monomeric MDP, MDP-dendrimers induced a markedly enhanced production of IL-12 p40, IL-1β and IL-6 and completely down-regulated surface expression of B7 and MHC class II. These results suggest a possible novel strategy based on controlled multimerization of minimal PAMP motifs on dendrimers for preparing molecularly defined immunostimulators with predictable bioactivities. 相似文献
72.
Vitor RV Martins MC Figueiredo EC Martins I 《Analytical and bioanalytical chemistry》2011,400(7):2109-2117
A method constituted by molecularly imprinted solid-phase extraction (MISPE) with high-performance liquid chromatography coupled
to diode array detector (HPLC-DAD) was developed for cotinine analysis in saliva samples. For this purpose, the separation
was carried out with a C18 reversed-phase column at 20 °C. The mobile phase which was composed of a mixture of 09:91 (v/v) acetonitrile/phosphate buffer, pH 6.3, was delivered with isocratic flow rate at 1.4 mL min−1. Employing MISPE, the best conditions were achieved with 1.5 mL of saliva plus 1.5 mL of 0.1 mol L−1 of acetate buffer, pH 5.5, which were then passed through a cartridge previously conditioned with 2 mL acetonitrile, 2 mL
methanol, and 2 mL of 0.1 mol L−1 sodium acetate buffer, pH 5.5. The washing was carried out with 1 mL deionized water, 1 mL of 0.1 mol L−1 sodium hydroxide, and 1 mL hexane; finally; the cotinine elution was carried out with 3 mL methanol/water (97.5: 2.5, v/v). Linearity ranged from 30 to 500 ng mL−1 with r > 0.99. Intra-assay, interassay precision, and accuracy ranged from 3.1% to 10.1%, 5.2% to 15.9%, and 99.22% to 111.17%,
respectively. The detection and quantification limits were 10 and 30 ng mL−1, respectively. This investigation has provided a reliable method for routine cotinine determination in saliva, and it is
an important tool for monitoring cigarette smoke exposure in smokers. The method was applied in five smokers’ samples who
consumed around five to 20 cigarettes per day and the values of cotinine in saliva were from 66.7 to 316.16 ng mL−1. 相似文献
73.
Figueiredo JL Mahata N Pereira MF Sánchez Montero MJ Montero J Salvador F 《Journal of colloid and interface science》2011,357(1):210-214
The influence of texture and surface chemistry on the phenol adsorption capacity of activated carbon fibres (ACFs) was studied. ACFs were prepared by carbonization of a phenolic textile fibre under nitrogen flow, followed by activation with H(2)O and CO(2) (under atmospheric pressure and supercritical state). The materials were characterised by N(2) and CO(2) adsorption, and by temperature programmed desorption studies. A strong correlation between the amount of adsorbed phenol and the micropore volume has been observed. The relationship between surface oxygen concentration and amount of physisorbed and chemisorbed phenol was assessed, and it was shown that higher amounts of surface oxygen groups decreased the phenol chemisorption capacity of ACFs. 相似文献
74.
Gass IA Gartshore CJ Lupton DW Moubaraki B Nafady A Bond AM Boas JF Cashion JD Milsmann C Wieghardt K Murray KS 《Inorganic chemistry》2011,50(7):3052-3064
The reaction of [Fe(II)(BF(4))(2)]·6H(2)O with the nitroxide radical, 4,4-dimethyl-2,2-di(2-pyridyl) oxazolidine-N-oxide (L(?)), produces the mononuclear transition metal complex [Fe(II)(L(?))(2)](BF(4))(2) (1) which has been investigated using temperature dependent susceptibility, Mo?ssbauer spectroscopy, electrochemistry, density functional theory (DFT) calculations, and X-ray structure analysis. Single crystal X-ray diffraction analysis and Mo?ssbauer measurements reveal an octahedral low spin Fe(2+) environment where the pyridyl donors from L(?) coordinate equatorially while the oxygen containing the radical from L(?) coordinates axially forming a linear O(?)··Fe(II)··O(?) arrangement. Magnetic susceptibility measurements show a strong radical-radical intramolecular antiferromagnetic interaction mediated by the diamagnetic Fe(2+) center. This is supported by DFT calculations which show a mutual spatial overlap of 0.24 and a spin density population analysis which highlights the antiparallel spin alignment between the two ligands. Similarly the monocationic complex [Fe(III)(L(-))(2)](BPh(4))·0.5H(2)O (2) has been fully characterized with Fe-ligand and N-O bond length changes in the X-ray structure analysis, magnetic measurements revealing a Curie-like S = 1/2 ground state, electron paramagnetic resonance (EPR) spectra, DFT calculations, and electrochemistry measurements all consistent with assignment of Fe in the (III) state and both ligands in the L(-) form. 2 is formed by a rare, reductively induced oxidation of the Fe center, and all physical data are self-consistent. The electrochemical studies were undertaken for both 1 and 2, thus allowing common Fe-ligand redox intermediates to be identified and the results interpreted in terms of square reaction schemes. 相似文献
75.
Yeast cell wall particles: a promising class of nature-inspired microcarriers for multimodal imaging
Figueiredo S Moreira JN Geraldes CF Rizzitelli S Aime S Terreno E 《Chemical communications (Cambridge, England)》2011,47(38):10635-10637
This communication demonstrates that yeast cell wall particles (YCWPs) are a promising class of nature-inspired biocompatible microcarriers for the delivery of amphipathic/lipophilic imaging reporters. When a paramagnetic MRI agent is loaded, the longitudinal relaxivity per particle at 0.5 T is the highest ever reported for Gd-based systems. 相似文献
76.
77.
Medeiros MR Prado LA Fernandes VC Figueiredo SS Coppede J Martins J Fiori GM Martinez-Rossi NM Beleboni RO Contini SH Pereira PS Fachin AL 《Natural product communications》2011,6(2):193-196
Tabernaemontana catharinensis root bark ethanol extract, EB2 fraction and the MMV alkaloid (12-methoxy-4-methylvoachalotine) were evaluated for their antimicrobial activities. T. catharinensis ethanol extract was effective against both strains of the dermatophyte Trichophyton rubrum at concentrations of 2.5 mg/mL (wild strain) and 1.25 mg/mL (mutant strain), while the EB2 fraction and MMV alkaloid showed a strong antifungal activity against wild and mutant strains with MIC values of <0.02 and 0.16 mg/mL, respectively. The EB2 fraction showed a strong antibacterial activity against ATCC strains of S. aureus, S. epidermidis, E. coli and P. aeruginosa with MICs from <0.02 to 0.04 mg/mL, as well as against resistant clinical isolates species of Enterococcus sp, Klebsiella oxytoca, Citrobacter, K. pneumoniae, P. mirabilis, S. aureus, S. epidermidis, E. coli and P. aeruginosa with MIC values ranging from 0.04 to 0.08 mg/mL. The MMV alkaloid presented a MIC of 0.16 mg/mL against the strains of S. aureus and E. coli ATCC. For the resistant clinical isolates Enterococcus sp, Citrobacter, S. aureus, S. epidermidis, E. coli and P. aeruginosa the MIC of MMV ranged from 0.08 to 0.31 mg/mL. The chromatography analysis of the EB2 fraction revealed the presence of indole alkaloids, including MMV, possibly responsible for the observed antimicrobial activity. 相似文献
78.
Fleury BG Figueiredo L Marcoli MI Teixeira VL Ferreira AB Pinto AC 《Natural product communications》2011,6(5):667-672
The distribution of fatty acids in 13 species of macroalgae (Chlorophyta, Ochrophyta and Rhodophyta) and 1 seagrass (Spartina sp), collected on the Rio de Janeiro state coast was determined. The results were evaluated in search of correlations between the taxonomic and phylogenetic position of these macrophytes. Statistical analyses showed the effectiveness as taxonomic and phylogenetic markers of the distribution of the methyl fatty acid esters in these macrophytes. 相似文献
79.
80.
Y.Q. Ma W. Figueiredo 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,1(1):103-106
By introducing boson operators, a quantum spherical XY model in the presence of a random field has been studied by the coherent state path integral approach. The phase diagram
is obtained, and the effects of the random-field fluctuations on the possibilities of the existence of a ferromagnetic phase are discussed. At the critical point, , the order parameter M describing the ordered ferromagnetic phase disappears as .Since the model is equivalent to a Bose system, we also show that the phase transition at zero temperature between the superfluid
and the disordered Mott insulator phases occurs at the chemical potential , where J0 is the strength of the exchange interaction. As the temperature T goes to zero, the asymptotic behavior of the entropy and the specific heat are and , respectively.
Received: 20 May 1997 / Accepted: 20 October 1997 相似文献