172 research outputs found
Effect of thermo-hygrometric exposure on FRP, natural stone and their adhesive interface
none3As well known, the performance of Fiber Reinforced Polymer (FRP) materials as external strengthening technique is strongly dependent on the bond behavior between FRP and substrate. Several experimental studies have been performed on this topic, however limited attention has still focused on the bond durability. In this paper, the effect of a thermo-hygrometric environment on the interface behavior FRP-calcareous natural stones is investigated. Each utilized materials (natural stone, adhesive, FRP sheets) was firstly exposed to the same thermo-hygrometric atmosphere; a relevant decay of mechanical properties has been found for the analyzed substrates (Lecce stone and Neapolitan tuff) while a negligible influence of the exposure has been observed for the composite reinforcements (CFRP and GFRP). The results regarding the variation of mechanical properties of the resins evidenced that the effect of the performed exposure is strictly correlated to the specific materials properties: a relevant degradation or even an improvement of mechanical performances has been,in fact, registered. The bond strength and the kind of failure were both analyzed as a function of the treatment used, as well as the strain and stress distribution at the interface. The kind of failure changed in some cases when passing from unconditioned to conditioned specimens; the bond strength, the maximum bond stress and the interface stiffness were affected by the treatment, manly depending on the adhesive resin deterioration. Finally, on the basis of the provisions given by the CNR-DT 200 R1/2013 document, the possibility of defining design relationships, able to take into account also durability aspects, is discussed.mixedM.S. Sciolti; M.A. Aiello; M. FrigioneSciolti, Margherita Stefania; Aiello, Maria Antonietta; Frigione, Mariaenric
Silica-based mesoporous materials as drug delivery system for methotrexate release.
Antineoplastic methotrexate has been loaded through different soaking procedures on silica-based mesoporous materials and, successively, released mimicking an oral administration. The materials were prepared using a self-assembly mechanism in the presence of cationic surfactants with alkyl chain of 16, 12, and 10 carbon atoms in the synthesis mixture to obtain different pore diameter in the porous structure. Mesoporous materials were prepared as pure silica sample and in the presence of Al(OH)(3) in the synthesis mixture. Only alumina-silica samples were able to load methotrexate. The amounts of drug loaded and the in vitro release kinetics are a function of the pore size of the materials
Soil Biological Responses under Different Vegetation Types in Mediterranean Area
The knowledge of the effects of fire on soil properties is of particular concern in Mediterranean areas, where the effects of vegetation type are still scarce also. This research aimed: to assess the properties of burnt soils under different vegetation types; to highlight the soil abiotic properties driving the soil microbial biomass and activity under each vegetation type; to compare the biological response in unburnt and burnt soils under the same vegetation type, and between unburnt and burnt soils under different vegetation types. The soils were collected at a Mediterranean area where a large wildfire caused a 50% loss of the previous vegetation types (holm oak: HO, pine: P, black locust: BL, and herbs: H), and were characterized by abiotic (pH, water, and organic matter contents; N concentrations; and C/N ratios) and biotic (microbial and fungal biomasses, microbial respiration, soil metabolic quotient, and hydrolase and dehydrogenase activities) properties. The biological response was evaluated by the Integrative Biological Responses (IBR) index. Before the fire, organic matter and N contents were significantly higher in P than H soils. After the fire, significant increases of pH, organic matter, C/N ratio, microbial biomass and respiration, and hydrolase and dehydrogenase activities were observed in all the soils, especially under HO. In conclusion, the post-fire soil conditions were less favorable for microorganisms, as the IBR index decreased when compared to the pre-fire conditions
Synthesis and antimicrobial activity of new 1-R-3-(2-Piridyl)-4-nitroso-5 carboxiethyl-1H-Pyrazoles
SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF NEW 1-R-3-(2-PIRIDYL)- 4-NITROSO- 5-CARBOXIETHYL-1H-PYRAZOLES.
Stefania Aielloa , Carmelo Massimo Maidab, Fabio Venturellab, Diego Planetac
Marco Giammancod, M.Milicib
a Dipartimento di Scienze e Tecnologie Molecolari e Biomolecolari, UniversitĂ degli Studi di Palermo
bDipartimento di Scienze per la Promozione della Salute G. D’ Alessandro, Università degli Studi di Palermo
cDipartimento dei Sistemi Agro-Abientali,UniversitĂ degli Studi di Palermo
d Dipartimednto di Studi Giuridici, Economici, Biomedici e Psicosociopedagogici delle Scienze Motorie e Sportive, UniversitĂ degli Studi di Palermo
Corresponding author: Stefania Aiello, Dipartimento di Scienze e Tecnologie Molecolari e Biomolecolari, UniversitĂ degli Studi di Palermo, Via Archirafi 32, 90123 Palermo, Italy; tel:+39.091 23896802; email: [email protected]
In recent years, epidemiological studies confirm the significant impact on human health by infections caused by pathogenic fungi. In fact, although the Candida genus is commensal and a constituent of the normal gut flora, it is responsible for opportunistic infections and can become pathogenic secondary to predisposing factors related to the host, like a comprimised immune system (AIDS, anti-cancer therapy, transplants), excessive prophylaxis with antimicrobial agents, and use of invasive catheters. Large-scale surveillance for fungal infections has demonstrated an increasing incidence of drug-resistant fungal pathogens. As a matter of fact, a significant number of fungi species (especially Candida glabrata and Candida krusei) exhibited primary resistance to Fluconazole or were less susceptible to Amphotericin B.
Furthermore, as a consequence of the toxicity of the currently used polyene antifungal drugs, which leads to interrupt the therapy, and the emergence of Candida species resistance to azole-based agents, there is an urgent need for developing alternative drug therapies.
In our previous study we have disclosed the synthesis and antifungal activity of a series of 4-nitrosopyrazoles that mainly displayed in vitro potent antifungal activity at no cytotoxic concentrations and that some of these compounds were 4 times more potent than Amphotericine B and Fluconazole respectively against Cryptococcus neoformans and Candida Krusei [1-4]
As part of our Structure Activity Relationships studies, we were interested in learning the influence of the steric and electronic effects of the substituent in position 5 of the 4-nitrosopyrazoles which had already showed powerful antimycotic activity.
Therefore, we synthetized title compounds and evaluated their antimycotic activity (fig1).
NNNCOOC2H5ONR
R: a=H, b= CH3, c=C2H5
Fig 1. Synthetized compounds
The 5-carboxiethylester group has made the antimycotic actity dramatically decay, confirming the necessity, for a good antimicotic activity, of derivatives in which the position 5 is free or substituted with little groups as a methyl shown the best antifungal activity.
[1] E. Aiello, S. Aiello, F. Mingoia, A. Bacchi, G. Pelizzi, C. Musiu, M. G. Setzu, A. Pani, P. La Colla and M. E. Marongiu. Synthesis and Antimicrobial activity of New 3-(1-R -3-methyl-4-nitroso-1H-5-pyrazolyl)-5-methylisoxazole derivatives, Bioorganic and Medicinal Chemistry, 2000, 8, 2719-2728
[2] Stefania Aiello; Enrico Aiello, Marica Orioli, Marina Carini, 3-(1-R-3-methyl-4-nitroso-1H-5-pyrazolyl)-5-methylisoxazoles: a new class of antifungal compounds. In vitro metabolism by rat liver:LC and LC-MS studies. Convegno Nazionale, Sorrento 18-22 Settembre 2002.
[3] S. Aiello, E. Aiello and M. Milici: “Synthesis and Antifungal Activity of new 3(5)-methyl-5(3)-(2-thiophenyl) and -(2-quinolyl)-1H-1-R-4-nitrosopyrazoles.Part V”. Polish-Austrian-German-Hungarian-Italian Joint Meeting on Medicinal Chemistry, Krakow, October 15-18, 2003
[4] Stefania Aiello, Antonio Macchiarulo, Maria Milici and Enrico Aiello, Sintesi e studi QSAR di nuovi derivati 3(5)-(2-X)-1R-1H-4-nitrosopirazoli: una classe di composti con potente attivitĂ antifungina in vitro. Parte VI XVII Convegno Nazionale della Divisione di Chimica Farmaceutica della SCI, Pisa 6-10 settembre 2004
Structural analyses in the study of behavior: From rodents to non-human primates
The term "structure" indicates a set of components that, in relation to each other, shape an organic complex. Such a complex takes on essential connotations of functionally unitary entity resulting from the mutual relationships of its constituent elements. In a broader sense, we can use the word "structure" to define the set of relationships among the elements of an emergent system that is not determined by the mere algebraic sum of these elements, but by the interdependence relationships of these components from which the function of the entire structure itself derives. The behavior of an integrated living being can be described in structural terms via an ethogram, defined as an itemized list of behavioral units. Akin to an architectural structure, a behavioral structure arises from the reciprocal relationships that the individual units of behavior establish. Like an architectural structure, the function of the resulting behaving complex emerges from the relationships of the parts. Hence, studying behavior in its wholeness necessitates not only the identification of its constitutive units in their autarchic individuality, but also, and importantly, some understanding of their relationships. This paper aimed to critically review different methods to study behavior in structural terms. First, we emphasized the utilization of T-pattern analysis, i.e., one of the most effective and reliable tools to provide structural information on behavior. Second, we discussed the application of other methodological approaches that are based on the analysis of transition matrices, such as hierarchical clustering, stochastic analyses, and adjusted residuals. Unlike T-pattern analysis, these methods allow researchers to explore behavioral structure beyond its temporal characteristics and through other relational constraints. After an overview of how these methods are used in the study of animal behavior, from rodents to non-human primates, we discussed the specificities, advantages and challenges of each approach. This paper could represent a useful background for all scientists who intend to study behavior both quantitatively and structurally, that is in terms of the reciprocal relationships that the various units of a given behavioral repertoire normally weave together
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