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991.
Francesca Papalini 《Journal of Mathematical Analysis and Applications》2002,273(1):137-152
In this paper we study nonlinear eigenvalue problems with Neumann boundary conditions and discontinuous terms. First we consider a nonlinear problem involving the p-Laplacian and we prove the existence of a solution for the multivalued approximation of it, then we pass to semilinear problems and we prove the existence of multiple solutions. The approach is based on the critical point theory for nonsmooth locally Lipschitz functionals. 相似文献
992.
993.
Francesca Benanti Antonio Giambruno Irina Sviridova 《Proceedings of the American Mathematical Society》2004,132(3):669-679
We consider associative PI-algebras over a field of characteristic zero. We study the asymptotic behavior of the sequence of multiplicities of the cocharacters for some significant classes of algebras. We also give a characterization of finitely generated algebras for which this behavior is linear or quadratic.
994.
Fabrizio Antonietti Francesco Minisci Carlo Punta Francesca Fontana 《Journal of fluorine chemistry》2004,125(2):205-211
Perfluoroalkyl radicals, generated by iodine abstraction from perfluoroalkyl iodides by phenyl radical, react with low selectivity with protonated heteroaromatic bases, due to their electrophilic character and the prevalent enthalpic effect on the reaction. In the presence of alkenes, perfluoroalkyl radicals add very rapidly to the double bond and the polar character of the radical adduct is reversed, allowing the selective substitution of protonated heteroaromatic bases. The mechanism of the reaction and the key role of enthalpic and polar effects are discussed. 相似文献
995.
996.
Simone Gastaldi Valentina Boscaro Eleonora Gianquinto Christina F. Sandall Marta Giorgis Elisabetta Marini Federica Blua Margherita Gallicchio Francesca Spyrakis Justin A. MacDonald Massimo Bertinaria 《Molecules (Basel, Switzerland)》2021,26(13)
In the search for new chemical scaffolds able to afford NLRP3 inflammasome inhibitors, we used a pharmacophore-hybridization strategy by combining the structure of the acrylic acid derivative INF39 with the 1-(piperidin-4-yl)1,3-dihydro-2H-benzo[d]imidazole-2-one substructure present in , a recently identified NLRP3 binder. A series of differently modulated benzo[d]imidazole-2-one derivatives were designed and synthesised. The obtained compounds were screened in vitro to test their ability to inhibit NLRP3-dependent pyroptosis and IL-1β release in PMA-differentiated THP-1 cells stimulated with LPS/ATP. The selected compounds were evaluated for their ability to reduce the ATPase activity of human recombinant NLRP3 using a newly developed assay. From this screening, compounds 9, 13 and 18, able to concentration-dependently inhibit IL-1β release in LPS/ATP-stimulated human macrophages, emerged as the most promising NLRP3 inhibitors of the series. Computational simulations were applied for building the first complete model of the NLRP3 inactive state and for identifying possible binding sites available to the tested compounds. The analyses led us to suggest a mechanism of protein–ligand binding that might explain the activity of the compounds. HS203873相似文献
997.
The mechanochemistry of the disulfide bridge--that is, the influence of an externally applied force on the reactivity of the sulfur-sulfur bond--is investigated by unrestricted Kohn-Sham theory. Specifically, we apply the COGEF (constrained geometry simulates external force) approach to characterize the mechanochemistry of the disulfide bond in three different chemical environments: dimethyl disulfide, cystine, and a 102-atom model of the I27 domain in the titin protein. Furthermore, the mechanism of the thiol-disulfide reduction reaction under the effect of an external force is investigated by considering the COGEF potential for the adduct and transition-state clusters. With the unrestricted Becke-three-parameter-Lee-Yang-Parr (UB3LYP) exchange-correlation functional in the 6-311++G(3df,3pd) orbital basis, the rupture force of dimethyl disulfide is 3.8 nN at a disulfide bond elongation of 35 pm. The interaction with neighboring groups and the effect of conformational rigidity of the protein environment have little influence on the mechanochemical characteristics. Upon stretching, we make the following observations: the diradical character of the disulfide bridge increases; the energy difference between the singlet ground state and low-lying triplet state decreases; and the disulfide reduction is promoted by an external force in the range 0.1-0.4 nN. Our model of the interplay between force and reaction mechanism is in qualitative agreement with experimental observations. 相似文献
998.
Eilertsen EA Giordanino F Lamberti C Bordiga S Damin A Bonino F Olsbye U Lillerud KP 《Chemical communications (Cambridge, England)》2011,47(43):11867-11869
A new zeotype titanium silicate oxidation catalyst with the STT topology has been synthesized from direct synthesis. Ti-STT has a microporous structure with small pore openings, allowing shape selective oxidation catalysis. The isomorphous substitution of Si by Ti in the framework has been confirmed by Raman, FT-IR, UV-VIS and XANES spectroscopies. 相似文献
999.
Haywood J Stokes FA Less RJ McPartlin M Wheatley AE Wright DS 《Chemical communications (Cambridge, England)》2011,47(14):4120-4122
The reaction of chromocene, Cp(2)Cr, with dilithiated 2,3-diphenylguanidine [(PhNH)(2)C=NH = L(2)H(3)] gives the novel, quadruply-bonded tetraanion [Cr(2)(L(2)H)(4)](4-). 相似文献
1000.
Francesca Caterina Izzo Elisabetta Zendri Guido Biscontin Eleonora Balliana 《Journal of Thermal Analysis and Calorimetry》2011,104(2):541-546
Thermogravimetry coupled with differential scanning calorimetry (TG–DSC) has been commonly used in the field of conservation
of Cultural Heritage for the study of art objects, especially for the characterisation of inorganic matrixes. In recent years,
thermal analyses have been applied to the study of organic painting materials. The advantages of performing TG–DSC are linked
to the fact that it is micro-destructive technique which does not require any treatment prior the analysis and provide useful
information in relatively short time. The aim of this study is to describe the application of TG–DSC on the study of oil binders
used in contemporary paints. Even if synthetic binders have become increasingly popular in the 20th century, many contemporary
artists still prefer the more traditional media: drying oils. Although the wish of recalling traditional methods, much practical
knowledge in paint preparation by mixing drying oil and pigments and in the behaviour of the mixture has been lost. This is
mainly due to the different composition of contemporary materials in comparison with the traditional ones and may sometimes
lead to different drying properties of the oil paint formulations and consequent problems in the art creation and conservation.
For answer to this artistic need and in particular to the difficulties outlined by artists themselves in producing and employing
oil paints, unpigmented and pigmented oil films were studied after a week, 1 and 2 years of natural drying under laboratory
conditions. Thermal analyses were performed in air flow: the focus of this research was, in fact, to study the thermal and
oxidative behaviours of young films for better understanding the very first processes leading to the formation of the film. 相似文献