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31.
Boga C Forlani L Calienni R Hindley T Hochkoeppler A Tozzi S Zanna N 《Natural product research》2011,25(4):417-421
A decoction of Capparis spinosa L. roots, widely used in the traditional folk medicine of southern Italy, was prepared and submitted to antibacterial activity tests, which showed an interesting bacteriostatic activity on the growth of Deinococcus radiophilus. Heterocyclic compounds were also recovered from the chloroformic extract of the roots. 相似文献
32.
Giovanni Petrillo Cinzia Tavani Lara Bianchi Alice Benzi Maria Maddalena Cavalluzzi Lara Salvagno Laura Quintieri Annalisa De Palma Leonardo Caputo Antonio Rosato Giovanni Lentini 《Molecules (Basel, Switzerland)》2021,26(13)
Twenty-two novel, variously substituted nitroazetidines were designed as both sulfonamide and urethane vinylogs possibly endowed with antimicrobial activity. The compounds under study were obtained following a general procedure recently developed, starting from 4-nitropentadienoates deriving from a common β-nitrothiophenic precursor. While being devoid of any activity against fungi and Gram-negative bacteria, most of the title compounds performed as potent antibacterial agents on Gram-positive bacteria (E. faecalis and three strains of S. aureus), with the most potent congener being the 1-(4-chlorobenzyl)-3-nitro-4-(p-tolyl)azetidine 22, which displayed potency close to that of norfloxacin, the reference antibiotic (minimum inhibitory concentration values 4 and 1–2 μg/mL, respectively). Since 22 combines a relatively efficient activity against Gram-positive bacteria and a cytotoxicity on eucharyotic cells only at 4-times higher concentrations (inhibiting concentration on 50% of the cultured eukaryotic cells: 36 ± 10 μM, MIC: 8.6 μM), it may be considered as a promising hit compound for the development of a new series of antibacterials selectively active on Gram-positive pathogens. The relatively concise synthetic route described herein, based on widely available starting materials, could feed further structure–activity relationship studies, thus allowing for the fine investigation and optimization of the toxico-pharmacological profile. 相似文献
33.
Monte Carlo methods have extensively been used and studied in the area of stochastic programming. Their convergence properties
typically consider global minimizers or first-order critical points of the sample average approximation (SAA) problems and
minimizers of the true problem, and show that the former converge to the latter for increasing sample size. However, the assumption
of global minimization essentially restricts the scope of these results to convex problems. We review and extend these results
in two directions: we allow for local SAA minimizers of possibly nonconvex problems and prove, under suitable conditions,
almost sure convergence of local second-order solutions of the SAA problem to second-order critical points of the true problem.
We also apply this new theory to the estimation of mixed logit models for discrete choice analysis. New useful convergence
properties are derived in this context, both for the constrained and unconstrained cases, and associated estimates of the
simulation bias and variance are proposed.
Research Fellow of the Belgian National Fund for Scientific Research 相似文献
34.
The Herrlich's problem from [8] whether there are nontrivial classes of topological spaces that are both almost reflective or injective and almost coreflective or projective, is investigated in a more general setting using cone and cocone modifications of the classes used in the problem. We look also at the problem for uniform spaces. Typical results: There is no nontrivial multiprojective and orthogonal class of topological spaces; There is a reflective class of uniform spaces that is almost coreflective in Unif.Work on this paper was initiated while the first author was a C.N.R. visitor of the University of L'Aquila. Partial financial assistence by Charles University Grant 349/1994 is also acknowledged. 相似文献
35.
Anna Tozzi 《Topology and its Applications》1983,16(1):69-80
Characterizations of epidense subcategories of topological categories and of existence of epidense hulls have been described in [2, 3, 4]. In this paper a similar characterization is given in a much more general setting; for example the category need not have products. The relationship between finite factorization structures and existence of epidense hulls is investigated. It is found to be analogous to the relationship between general factorization structures and epireflective hulls. 相似文献
36.
Alberta Terzi Nunzia Gallo Simona Bettini Teresa Sibillano Davide Altamura Marta Madaghiele Liberato De Caro Ludovico Valli Luca Salvatore Alessandro Sannino Cinzia Giannini 《Macromolecular bioscience》2020,20(5)
Collagen represents one of the most widely used biomaterial for scaffolds fabrication in tissue engineering as it represents the mechanical support of natural tissues. It also provides physical scaffolding for cells and it influences their attachment, growth, and tissue regeneration. Among all fibrillary collagens, type I is considered one of the gold standard for scaffolds fabrication, thanks to its high biocompatibility, biodegradability, and hemostatic properties. It can be extracted by chemical and enzymatic protocols from several collagen‐rich tissues, such as tendon and skin, of different animal species. Both the extraction processes and the manufacturing protocols for scaffolds fabrication provide structural and mechanical changes that can be tuned in order to deeply impact the properties of the final biomaterial. The aim of this review is to discuss the role of X‐rays to study structural changes of type I collagen from fresh collagen‐rich tissues (bovine, equine, fish) to the final scaffolds, with the aim to screen across available collagen sources and scaffolds fabrication protocols to be used in tissue regeneration. 相似文献
37.
Simultaneous estimation in nonlinear multivariate regression contexts is a complex problem in inference. In this paper, we compare the methodology suggested in the literature for an unknown covariance matrix among response components, the methodology by Beauchamp and Cornell (B&C), with the standard nonlinear least squares approach (NLS). In the first part of the paper, we contrast B&C and the standard NLS, pointing out, from the theoretical point of view, how a model specification error could affect the estimation. A comprehensive simulation study is also performed to evaluate the effectiveness of B&C versus standard NLS under both correct and misspecified models. Several alternative models are considered to highlight the consequences of different types of specification error. An application to a real dataset within the context of quantitative marketing is presented. 相似文献
38.
In the same spirit of the classical Leau-Fatou flower theorem, we prove the existence of a petal, with vertex at the Wolff
point, for a holomorphic self-map f of the open unit disc Δ ⊂ ℂ of parabolic type. The result is obtained in the framework of two interesting dynamical situations
which require different kinds of regularity of f at the Wolff point τ: f of non-automorphism type and
or f injective of automorphism type, f∈C
3+ɛ(τ) and
.
Partially supported by PRIN Proprietà geometriche delle varietà reali e complesse.
Partially supported by GNSAGA of the Istituto Nazionale di Alta Matematica, Rome. 相似文献
39.
Dr. Artur Ciesielski Jürgen Weippert Dr. Artur Böttcher Yuyoung Shin Georgian Melinte Prof. Dr. Ovidiu Ersen Dr. Cinzia Casiraghi Prof. Dr. Xinliang Feng Prof. Dr. Klaus Müllen Prof. Dr. Manfred M. Kappes Prof. Dr. Paolo Samorì Dr. Marco Cecchini 《Chemphyschem》2016,17(3):352-357
Providing a quantitative understanding of the thermodynamics involved in molecular adsorption and self‐assembly at a nanostructured carbon material is of fundamental importance and finds outstanding applications in the graphene era. Here, we study the effect of edge perchlorination of coronene, which is a prototypical polyaromatic hydrocarbon, on the binding affinity for the basal planes of graphite. First, by comparing the desorption barrier of hydrogenated versus perchlorinated coronene measured by temperature‐programmed desorption, we quantify the enhancement of the strength of physisorption at the single‐molecule level though chlorine substitution. Then, by a thermodynamic analysis of the corresponding monolayers based on force‐field calculations and statistical mechanics, we show that perchlorination decreases the free energy of self‐assembly, not only enthalpically (by enhancing the strength of surface binding), but also entropically (by decreasing the surface concentration). The functional advantage of a chemically modulated 2D self‐assembly is demonstrated in the context of the molecule‐assisted liquid‐phase exfoliation of graphite into graphene. 相似文献
40.
Francesca Scazzocchio Stefania Garzoli Cinzia Conti Claudia Leone Clio Renaioli Federico Pepi 《Natural product research》2016,30(17):1909-1918
Because of the emergence of multi-drug resistance bacteria and fungi, alternatives to conventional antimicrobial therapy are needed. This study aims to evaluate in vitro the antimicrobial activity of: Mirtus communis, Coriandrum sativum, Pelargonium capitatum, Cuminum cyminum, Ocimum basilicum, Citrus aurantium amara, Cymbopogon. winterianus, Cymbopogon martini, Salvia sclarea, Melaleuca alternifolia and Mentha suaveolens essential oils on bacteria and fungi, in relation to their chemical composition. The potential interaction of M. alternifolia (TTO), C. sativum (CDO) and M. suaveolens (EOMS) essential oils when used in combination with gentamicin and fluconazole has been evaluated. The results obtained showed a synergic effect on some bacteria and fungi, with FICI values ≤5. The cytotoxicity of TTO, CDO and EOMS was investigated towards HeLa cells. Only EOMS did not result cytotoxic at the active concentrations on micro-organisms. Further studies are necessary to obtain optimal ratios and dosing regimens for higher therapeutic efficacy and to decrease toxicological profiles. 相似文献