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排序方式: 共有428条查询结果,搜索用时 156 毫秒
171.
Eleonora Casula Maria Manconi Jos Antonio Vzquez Tania Belen Lopez-Mendez Jos Luis Pedraz Esteban Calvo Antonio Lozano Marco Zaru Andreia Ascenso Maria Letizia Manca 《Molecules (Basel, Switzerland)》2021,26(21)
The extract of Cardiospermum halicacabum L. (C. halicacabum) obtained from flower, leaf and vine was loaded into modified phospholipid vesicles aiming at obtaining sprayable, biocompatible and effective nasal spray formulations for the treatment of nasopharyngeal diseases. Penetration enhancer-containing vesicles (PEVs) and hyalurosomes were formulated, and stabilized by adding a commercial gelatin from fish (20 mg/mL) or chondroitin sulfate from catshark cartilages (Scyliorhinus canicula, 20 mg/mL). Cryo-TEM images confirmed the formation of spherical vesicles, while photon correlation spectroscopy analysis disclosed the formation of small and negatively-charged vesicles. PEVs were the smaller vesicles (~100 nm) along with gelatin-hyalurosomes (~120 nm), while chondroitin-PEVs and chondroitin-hyalurosomes were larger (~160 nm). Dispersions prepared with chondroitin sulfate were more homogeneous, as the polydispersity index was ~0.15. The in vitro analysis of the droplet size distribution, average velocity module and spray cone angle suggested a good spray-ability and deposition of formulations in the nasal cavity, as the mean diameter of the droplets was in the range recommended by the Food and Drug Administration for nasal targets. The spray plume analysis confirmed the ability of PEVs, gelatin-PEVs, hyalurosomes and gelatin-hyalurosomes to be atomized in fine droplets homogenously distributed in a full cone plume, with an angle ranging from 25 to 30°. Moreover, vesicles were highly biocompatible and capable of protecting the epithelial cells against oxidative damage, thus preventing the inflammatory state. 相似文献
172.
Visnja Ognjenovic Vladimir Brtka Jelena Stojanov Eleonora Brtka Ivana Berkovic 《Entropy (Basel, Switzerland)》2022,24(5)
The preprocessing of data is an important task in rough set theory as well as in Entropy. The discretization of data as part of the preprocessing of data is a very influential process. Is there a connection between the segmentation of the data histogram and data discretization? The authors propose a novel data segmentation technique based on a histogram with regard to the quality of a data discretization. The significance of a cut’s position has been researched on several groups of histograms. A data set reduct was observed with respect to the histogram type. Connections between the data histograms and cuts, reduct and the classification rules have been researched. The result is that the reduct attributes have a more irregular histogram than attributes out of the reduct. The following discretization algorithms were used: the entropy algorithm and the Maximal Discernibility algorithm developed in rough set theory. This article presents the Cuts Selection Method based on histogram segmentation, reduct of data and MD algorithm of discretization. An application on the selected database shows that the benefits of a selection of cuts relies on histogram segmentation. The results of the classification were compared with the results of the Naïve Bayes algorithm. 相似文献
173.
Eleonora Oliva Federico Fanti Sara Palmieri Eduardo Viteritti Fabiola Eugelio Alessia Pepe Dario Compagnone Manuel Sergi 《Molecules (Basel, Switzerland)》2022,27(10)
Polyphenols (PCs) are a numerous class of bioactive molecules and are known for their antioxidant activity. In this work, the potential of the quadrupole/linear ion trap hybrid mass spectrometer (LIT-QqQ) was exploited to develop a semi-untargeted method for the identification of polyphenols in different food matrices: green coffee, Crocus sativus L. (saffron) and Humulus lupulus L. (hop). Several conjugate forms of flavonoids and hydroxycinnamic acid were detected using neutral loss (NL) as a survey scan coupled with dependent scans with enhanced product ion (EPI) based on information-dependent acquisition (IDA) criteria. The presented approach is focused on a specific class of molecules and provides comprehensive information on the different conjugation models that are related to specific base molecules, thus allowing a quick and effective identification of all possible combinations, such as mono-, di-, or tri-glycosylation or another type of conjugation such as quinic acid esters. 相似文献
174.
1H and 13C NMR spectral assignments of 1,1′‐(((ethane‐1,2‐diylbis(oxy))bis(4,1‐phenylene))bis(methylene))‐bispyridinium and ‐bisquinolinium bromide derivatives
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175.
176.
Eleonora M. van der Wenden Sarah L. Price Robert P. Apaya Adriaan P. IJzerman Willem Soudijn 《Journal of computer-aided molecular design》1995,9(1):44-54
Summary The electrostatic properties of adenosine-based agonists and xanthine-based antagonists for the adenosine A1 receptor were used to assess various proposals for their relative orientation in the unknown binding site. The electrostatic properties were calculated from distributed multipole representations of SCF wavefunctions. A range of methods of assessing the electrostatic similarity of the ligands were used in the comparison. One of the methods, comparing the sign of the potential around the two molecules, gave inconclusive results. The other approaches, however, provided a mutually complementary and consistent picture of the electrostatic similarity and dissimilarity of the molecules in the three proposed relative orientations. This was significantly different from the results obtained previously with MOPAC AM1 point charges. In the standard model overlay, where the aromatic nitrogen atoms of both agonists and antagonists are in the same position relative to the binding site, the electrostatic potentials are so dissimilar that binding to the same receptor site is highly unlikely. Overlaying the N6-region of adenosine with that near C8 of theophylline (the N6-C8 model) produces the greatest similarity in electrostatic properties for these ligands. However, N6-cyclopentyladenosine (CPA) and 1,3-dipropyl-8-cyclopentylxanthine (DPCPX) show greater electrostatic similarity when the aromatic rings are superimposed according to the flipped model, in which the xanthine ring is rotated around its horizontal axis. This difference is mainly attributed to the change in conformation of N6-substituted adenosines and could result in a different orientation for theophylline and DPCPX within the receptor binding site. However, it is more likely that DPCPX also binds according to the N6-C8 model, as this model gives the best steric overlay and would be favoured by the lipophilic forces, provided that the binding site residues could accommodate the different electrostatic properties in the N6/N7-region. Finally, we have shown that Distributed Multipole Analysis (DMA) offers a new, feasible tool for the medicinal chemist, because it provides the use of reliable electrostatic models to determine plausible relative binding orientations.Abbreviations DMA
distributed multipole analysis
- SCF
self-consistent field
- CPA
N6-cyclopentyladenosine
- DPCPX
1,3-dipropyl-8-cyclopentylxanthine
-
R-PIA
R-1-phenyl-2-propyladenosine
-
S-PIA
S-1-phenyl-2-propyladenosine 相似文献
177.
Dorina Strugaru Eleonora Trif V. Cristea Gabriela Gheorghe R. Russu 《Radiation Physics and Chemistry》1995,45(6):917-922
The EPR spectroscopy has been used to study the interaction of vanadium pentoxide with H-ZSM-5 zeolite, supplied by ICITPR-Ploiesti, Romania, occurring at the calcination of the mixture at temperatures from 100 to 1000°C, in air, followed by evacuation at 20°C, as well as for those rehydrated at room temperature. The EPR method is also used to follow the thermal stability of the investigated zeolite, the framework alteration and the nature of VO2+ complexes formed during solid phase reaction. At least two types VO2+ centres were identified in H-ZSM-5 zeolite. One of them being ascribed to dehydrated VO2+ complexes in cationic sites, with C4v ligand field symmetry and the second one corresponding to the hydrated complex with a square bipyramidal symmetry, D4h. Increasing covalent character, for the in-plane σ-bond and increasing ionic character for the out-of-plane π bond, have been found on rehydrated samples. For a low content of oxide ( 5% wt V2O5) in a mixture the thermal stability, T = 1070°C, of the zeolite phase is not affected by the presence of the reaction products. 相似文献
178.
Miranda KM Dutton AS Ridnour LA Foreman CA Ford E Paolocci N Katori T Tocchetti CG Mancardi D Thomas DD Espey MG Houk KN Fukuto JM Wink DA 《Journal of the American Chemical Society》2005,127(2):722-731
The recent determination that Angeli's salt may have clinical application as a nitrogen oxide donor for treatment of cardiovascular diseases such as heart failure has led to renewed interest in the mechanism and products of thermal decomposition of Angeli's salt under physiological conditions. In this report, several mechanisms are evaluated experimentally and by quantum mechanical calculations to determine whether HNO is in fact released from Angeli's salt in neutral, aerobic solution. The mechanism of product autoxidation is also considered. 相似文献
179.
Ishmaeva E. A. Kataev V. E. Vereshchagina Ya. A. Fattakhova G. R. Bazhanova Z. G. Kataev A. V. 《Russian Journal of General Chemistry》2003,73(6):888-895
The structure of cyanophosphines and their oxides was studied by ab initio (RHF/6-31G**) and semiempirical (PM3) methods. Both methods predict that MeOP(CN)2, (MeO)2PCN, and (MeO)2P(O)CN exist in noneclipsed antiperiplanar and synclinal conformations. The calculation results nicely agree with measured dipole moments and Kerr constants of these compounds. The phenyl and diphenyl derivatives PhP(CN)2, Ph2PCN, Ph(Et)PCN, and Ph2P(O)CN prefer forms in which the phenyl ring plane is eclipsing the phosphorus lone electron pair or the phosphoryl bond. The interactions of the phosphorus lone electron pair with the phenyl ring and with the cyano group are lacking in the title compounds. 相似文献
180.
Antonio Massa Eleonora M. De Lorenzo Arrigo Scettri 《Journal of molecular catalysis. A, Chemical》2006,250(1-2):27-29
The oxidation of sulfides to sulfoxides has been conveniently performed under heterogeneous and solvent-free conditions employing polymeric Ti(IV) glycolate as reusable catalyst and t-butyl hydroperoxide as oxygen donor. The catalyst can be very efficiently recovered and reused several times without any significant change in reactivity and selectivity. 相似文献