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排序方式: 共有214条查询结果,搜索用时 31 毫秒
81.
Gabriella Guerrini Letizia Crocetti Simona Daniele Antonella Iacovone Niccol Cantini Claudia Martini Fabrizio Melani Claudia Vergelli Maria Paola Giovannoni 《Journal of heterocyclic chemistry》2019,56(5):1571-1580
A new series of 3,6‐disubstituted pyrazolo[1,5‐a]quinazolines (PQs) and their 4,5‐dihydro derivatives as isomer of the potent 3,8‐PQ previously reported by us as high affine GABAA receptor subtype ligands, have been synthesized and evaluated. These new compounds have been obtained exploiting a different synthetic pathway with respect to the corresponding 3,8‐disubstituted isomers, proposing again the same groups present in the reference 3,8‐PQ. The movement of the substituents from position 8 to position 6 is detrimental for binding recognition, suggesting that the substituents at position 6 are not properly oriented to form adequate interaction with hydrogen bond point and lipophilic area in the receptor protein, as demonstrated in molecular modeling studies. 相似文献
82.
Lynda Idjouadiene Toufik A. Mostefaoui Hocine Djermoune Letizia Bonizzoni 《X射线光谱测定》2019,48(5):505-512
The North African regions boast a multimillenary tradition of pottery production that represents a decisive progress in all societies. In this paper, we present the analysis of several fragments of pottery dating from the Middle Ages and collected in the archaeological site of Gouraya in Béjaïa (Algeria). Energy-dispersive X-ray fluorescence measurements were performed to obtain the elemental composition of the clays and to attempt a classification of the samples through multivariate analysis methods, connecting them to the archaeological information about the sites. Hierarchical clusters analysis (HCA) identified two possible different groups, related to different production sites, even if only one source of clay seem to be used, consistently with the geological contest. Based on the results, a tentative provenance interpretation could be proposed on historical bases. We put in place a strategy that made it possible to perform provenance studies respecting sample integrity as we aim to extend our research also to integer and well-preserved object from museum, to create a database for Algerian production of in the Middle Ages. 相似文献
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84.
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
85.
Letizia Mencaroni Benedetta Carlotti Fausto Elisei Assunta Marrocchi Anna Spalletti 《Chemical science》2022,13(7):2071
In this study, we report strong experimental evidence for singlet fission (SF) in a new class of fluorene-based molecules, exhibiting two-branched donor–acceptor structures. The time-resolved spectroscopic results disclose ultrafast formation of a double triplet state (occurring in few picoseconds) and efficient triplet exciton separation (up to 145% triplet yield). The solvent polarity effect and the role of intramolecular charge transfer (ICT) on the SF mechanism have been thoroughly investigated with several advanced spectroscopies. We found that a stronger push–pull character favors SF, as long as the ICT does not act as a trap by opening a competitive pathway. Within the context of other widely-known SF chromophores, the unconventional property of generating high-energy triplet excitons (ca. 2 eV) via SF makes these materials outstanding candidates as photosensitizers for photovoltaic devices.We found that a stronger push–pull character favours SF, as long as the ICT does not act as a trap. The unique property of generating high-energy triplets (ca. 2 eV) via SF makes these materials outstanding candidates for photovoltaic applications. 相似文献
86.
87.
Stefano Scoditti Francesco Chiodo Gloria Mazzone Sbastien Richeter Emilia Sicilia 《Molecules (Basel, Switzerland)》2022,27(13)
The photophysical properties of two classes of porphyrins and metalloporphyrins linked to N-heterocyclic carbene (NHC) Au(I) complexes have been investigated by means of density functional theory and its time-dependent extension for their potential application in photodynamic therapy. For this purpose, the absorption spectra, the singlet–triplet energy gaps, and the spin–orbit coupling (SOC) constants have been determined. The obtained results show that all the studied compounds possess the appropriate properties to generate cytotoxic singlet molecular oxygen, and consequently, they can be employed as photosensitizers in photodynamic therapy. Nevertheless, on the basis of the computed SOCs and the analysis of the metal contribution to the involved molecular orbitals, a different influence in terms of the heavy atom effect in promoting the intersystem crossing process has been found as a function of the identity of the metal center and its position in the center of the porphyrin core or linked to the peripheral NHC. 相似文献
88.
Marta Letizia Antonelli Camillo La Mesa Rosalia Fortunata Tornelli Caterina Letizia 《Thermochimica Acta》2007,456(1):13-18
Negatively charged vesicles made of non-stoichiometric amounts of sodium dodecylsulfate and cetyltrimethylammonium bromide were characterised by physico-chemical methods. Interactions with lysozyme were examined by calorimetry. A remarkable heat effect is observed upon diluting the protein with the vesicular pseudo-solvent. The maximum ΔHbind value occurs at complete vesicle charge neutralisation by the protein. 相似文献
89.
Massimo Gazzano Viscardo Malta Maria Letizia Focarete Mariastella Scandola Richard A. Gross 《Journal of Polymer Science.Polymer Physics》2003,41(10):1009-1013
The crystal structure of poly(ω‐pentadecalactone) (PPDL) synthesized by enzyme‐catalyzed polymerization was determined by full‐profile refinement. A pseudo‐orthorombic monoclinic unit cell with dimensions a = 7.49(1), b = 5.034(9), and c = 20.00(4)Å (fiber axis), and α = 90.06(4)° hosts two monomeric units belonging to polymer chains with opposite orientation, according to the P21 space‐group symmetry. A close similarity to the crystal structure of poly(?‐caprolactone) was evident. However, the even number of backbone atoms in the monomer unit of PPDL leads to a lower crystal symmetry. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1009–1013, 2003 相似文献
90.