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151.
D. Dal Ben C. Lambertucci S. Vittori R. Volpini G. Cristalli 《Journal of the Iranian Chemical Society》2005,2(3):176-188
G-protein-coupled receptors (GPCRs) represent the largest known family of signal-transducing proteins and transmit signals for light and many extracellular regulatory molecules. GPCRs are dysfunctional or dysregulated in several human diseases and are estimated to be the targets of ~40% of the drugs used in clinical medicine today. Receptors for adenosine belong to this family, and so far four subtypes, the A1, A2A, A2B, and A3, have been recognized. The activation of adenosine receptors (ARs) is largely responsible for the variety of effects produced by adenosine throughout several organ systems. Based on the wide (and often beneficial) effects attributed to the accumulation of endogenously released adenosine, it has long been considered that regulation of ARs has considerable therapeutic potential. In this review, we focus on recent work on adenosine receptors as therapeutic targets and, in particular, on molecular modelling support to adenosine receptors targeting. 相似文献
152.
A prototype DRIFTS flow reaction chamber was designed and developed in order to find analytical application in the study of heterogeneous catalysts operating at high temperatures under fast transient gas feed conditions. Minimisation of dead-volumes allows gas replacement in 8-10 s at 10 mL min−1 total flow. To overcome problems related to the reactivity of the cell walls under alternating oxidizing/reducing gases, the cell was built with Inconel 600™, which was tested to be very inert even at high temperatures. The sample holder, which was developed to closely resemble a micro plug-flow reactor, poses some problems in terms of heat transfer to the outer body of the cell (limiting then the maximum reachable temperature) and of the correct measurement of the actual sample temperature. These problems were solved with a careful re-design of the upper part of the cell. The second prototype thus derived is able to reach temperatures up to 803 K and allows gas replacement in less than 4 s at 10 mL min−1. The cell is inserted in a MCT-FT-IR, which allows to collect high quality spectra with a 1 s time-resolution. The downstream flow can be analysed by a quadrupole mass spectrometer equipped with an enclosed source and by a commercial GC. The performances of this prototype cell are presented showing some tests carried out with ceria-zirconia (CexZr1−xO2) catalysts for CO abatement under real operando conditions. 相似文献
153.
Zacharias CR Lemes MR Pino Júnior AD Santo Orcero D 《Journal of computational chemistry》2003,24(7):869-875
This article introduces an efficient method to generate structural models for medium-sized silicon clusters. Geometrical information obtained from previous investigations of small clusters is initially sorted and then introduced into our predictor algorithm in order to generate structural models for large clusters. The method predicts geometries whose binding energies are close (95%) to the corresponding value for the ground-state with very low computational cost. These predictions can be used as a very good initial guess for any global optimization algorithm. As a test case, information from clusters up to 14 atoms was used to predict good models for silicon clusters up to 20 atoms. We believe that the new algorithm may enhance the performance of most optimization methods whenever some previous information is available. 相似文献
154.
Zaramella A Conti N Dal Cin M Paio A Seneci P Gehanne S 《Journal of combinatorial chemistry》2001,3(5):410-420
The presence of dansyl or dabsyl chromogenic moieties in a solid-phase analytical construct, an assembly of linkers/spacers/sensitizers for improving analytical characterization, allows the accurate estimation of products from solid-phase synthesis by UV detection during liquid chromatography-mass spectrometry analysis in the cleavage solution. The spectroscopic properties of dansylated molecules have been evaluated to verify the "compound-independent UV absorption" necessary for using the chromophore in the accurate estimation. First, measurements on commercial dansylated compounds were made, then a series of construct-like molecules were prepared by solution-phase synthetic procedures and their UV properties were determined. Compound calibration curves were determined, and UV absorption was shown to be both proportional to the compound concentration and compound-independent. An example of a dansyl construct derivative was then prepared on a polymeric matrix, and an accurate estimation using the calibration curves was carried out in the cleavage solution. Good agreement was found between the calculated amount of released compound using the UV calibration curves and the calculated amount using both (1)H NMR and LC/chemiluminescent nitrogen detection quantitative techniques. Preliminary studies using the dabsyl moiety as an improved chromophore with higher wavelength and extinction coefficient are also reported. 相似文献
155.
Alberto Dal Corso Valentina Borlandelli Cristina Corno Paola Perego Laura Belvisi Luca Pignataro Cesare Gennari 《Angewandte Chemie (International ed. in English)》2020,59(10):4176-4181
Self‐immolative (SI) spacers are sophisticated chemical constructs designed for molecular delivery or material degradation. We describe herein a (S)‐2‐(aminomethyl)pyrrolidine SI spacer that is able to release different types of anticancer drugs (possessing either a phenolic or secondary and tertiary hydroxyl groups) through a fast cyclization mechanism involving carbamate cleavage. The high efficiency of drug release obtained with this spacer was found to be beneficial for the in vitro cytotoxic activity of protease‐sensitive prodrugs, compared with a commonly used spacer of the same class. These findings expand the repertoire of degradation machineries and are instrumental for the future development of highly efficient delivery platforms. 相似文献
156.
Some tesserae of San Marco Basilica (Venice) have been investigated in order to understand the possibilities of non-destructive investigation in the study of glass mosaics. In particular, the tesserae belonging to a mosaic piece coming from the Baptistery (dated about 1340) have been previously investigated by optical microscopy (table and portable) and divided in groups according with their optical appearance. Then the results have been compared with PIGE-PIXE, p-XRF, XPS data and elaborated by PCA. The results show that green tesserae and the “cartellina” (both characterised by low cromophore amounts) can be difficultly studied by portable instruments. On the other side, the red tesserae, although similar from the optical point of view, do not always show the same composition. 相似文献
157.
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160.
Bianca Schweitzer Arlindo C. Felippe Alexandre Dal Bó Edson Minatti Dino Zanette 《Macromolecular Symposia》2005,229(1):208-216
Summary: In this study sodium cholate (NaC) was used as a representative bile salt for the competitive binding between NaC and sodium dodecyl sulfate (SDS) in bovine serum albumin (BSA), in 0.02 M tris-HCl buffer solution at pH 7.50 and 25 °C. The NaC and SDS associations with BSA were monitored at low surfactant concentrations where only this specific binding process can develop. The applied method to monitor the binding was based on the analysis of the effect of SDS and NaC concentrations and their mixtures upon the fluorescence intensity of the BSA tryptophan residues. This consists of the measurement of the surfactant monomer partitioning between the dispersion medium and the microaggregates on the protein molecule where the binding is indicated by the quenching of the fluorescence chromophores. Experimentally, varying the protein concentration, the surfactant concentration needed to reach a given Io/I ratio (Io and I are the intensities with and without protein, respectively) was measured. The analyses, based on the average number of surfactant molecules bound on the protein, indicated that the SDS is a more efficient quencher than the bile salt. The need for 4–6 NaC bound molecules to give the same protein quenching efficiency by a single molecule of SDS was estimated. We concluded that the differences in the competitive binding on the protein are exclusively related to the quenching efficiency in the formation of the nonfluorescent fluorophore-quencher complex via a physical contact and static quenching process. 相似文献