87,064 research outputs found
Faulting and fracturing of carbonate rocks: New insights into deformation mechanisms, petrophysics and fluid flow properties
No full textPreface to the Volum
Deformation mechanisms and hydraulic properties of normal and strike-slip fault zones in porous carbonates outcropping in central and southern Italy
No full textDeformation of porous carbonate grainstones takes generally place by compactive shear banding, which initially produces single bands that may evolve during incremental strain into zones of multiple bands and, eventually, fault zones with discrete slip surfaces (Tondi et al., 2006). The processes associated to increased deformation are recorded by the aforementioned structural elements (Tondi, 2007; Tondi et al., 2012; Cilona et al., 2012). In fact, each of the structural elements is characterized by a different texture, porosity, and dimensional attributes (i.e. length, thickness, displacement).
Fault zones are characterized by a inner fault core made up of cataclastic material surrounded by thick damage zone including single bands and zones of bands. Within this latter structural domain, shear-enhanced compaction took place, and wide zones of precipitated calcite cement. In this work, we present the results of in situ permeability measurements carried out using a portable field permeameter (TinyPerm II Portable Air Permeameter, Balsamo et al. 2010) along normal and strike-slip fault zones crosscutting high-porosity carbonate grainstones of Cretaceous (Majella Mountain, Abruzzo), and Lower Pleistocene (Favignana Island, Sicily) ages. We studied nine Sub-Seismic Resolution Faults (SSRF), whose displacements are comprised between 10 and 200 cm.
With the general objective of improving the knowledge on the control exerted by SSRF on the bulk permeability of porous carbonate reservoir/aquifers, this work is aimed at establishing meaningful relationships between deformation processes (taking place within fault damage zones and fault cores) and the measured permeability values
Carte e Tavole fuori testo
No full textUno studio importante sul territorio e i paesaggi dell'insediamento antico di Torre di Satriano. Una ricerca portata avanti dall'Università della Basilicata che ha coinvolto numerosi studenti, ricercatori e docenti di molte università italiane e straniere. I risultati delle indagini di superficie permettono di ricostruire la storia del centro italico dell'età del Ferro e le trasformazioni del territorio dal Il millennio a.C. fino al Medioevo. L'articolo tratta della gestione informatizzataed integrata di questi dati derivanti da ricognizione di superficie e attività di scavo archeologico. Carte e Tavole fuori testo
Feeding Skills and Physiological Response to Feeding in Infants With Complex Congenital Heart Disease
No full textAbstract
Date Presented 3/30/2017
The objectives of this study were to characterize the feeding skills of infants with complex congenital heart disease and to measure physiological parameters during feeding. Results suggest clinical signs of decreased feeding skill and physiological changes that remain up to 60 min after the feeding.
Primary Author and Speaker: Kelly Tanner
Additional Authors and Speakers: Lauren Justice
Contributing Authors: Tondi Harrison, Maria Anderson, Brian F. Joy</jats:p
A multidisciplinary approach to the design of novel inhibitors for KPC-2
No full textBackground. The emergence and dissemination of multi drug resistant (MDR) Gram-negative pathogens resistant to all available antibiotics poses a significant threat in clinical therapy. Among them, Klebsiella Pneumoniae clinical isolates overexpressing KPC-2 carbapenemase are the most worrisome, extending bacterial resistance to last resort carbapenems. [1-2]
Materials/methods. Four boronic acid derivatives were designed and tested in vitro vs KPC-2.[3] In biological assays their ability to synergize last generation antibiotics was evaluated. X-ray crystallography was applied to confirm binding orientation and new compounds ability to reach consensus-binding sites in carbapenemases (Figure 1).
Results. For the most actives active compounds nanomolar affinity was achieved. The best inhibitor has nanomolar affinity for the enzyme, a ligand efficiency of 0.78 kcal mol–1 and a molecular weight of 158 Da validating it as lead-like molecule. In biological assays against Escherichia coli overexpressing KPC-2 new derivatives restored susceptibility to cefotaxime, aztreonam and last resort carbapenems. Two crystallographic binary complexes of the best inhibitors binding KPC-2 were obtained at high resolution.
Conclusion. We investigate the molecular recognition requirements in KPC-2 active site by boronic acid derivatives. Kinetic descriptions of slow binding, time dependent inhibition and interactions geometries in KPC-2 were fully investigated.
This study will guide further lead optimization and development of more effective KPC-2 inhibitors.
Figure 1
References
[1] Jean-Marie Frère, Eric Sauvage and Frédéric Kerff. “From “An enzyme able to destroy penicillin » to carbapenemases: 70 years of beta-lactamase misbehavior” Current Drug Targets, (2016). Volume 16. (E-pub ahead of print).
[2] Tondi, D.; Cross, S.; Venturelli, A.; Costi, MP; Cruciani, G.; Spyrakis, F. Current Drug Targets 2016 17, no. 9 (2016)
[3] Tondi,D.; Venturelli,A.; Bonnet,R.; Pozzi, C.; Shoichet, BK.; Costi, M.P. JMC. 2014. 57 (12), pp 5449–5458
Contribution to floristic knowledge of Middle Latina Valley (Lazio - Central Apennines)
No full textIn this paper the Authors show the preliminary results of a floristic research on the Latina Valley in Lazio Region. This research was carried out in the period 2009-2011. Amongst the about 500 species recorded, 50 entities are to be considered rare for the Latium region. In particular for the following taxa: Isoëetes duriei, I. hystrix, I. velata, Exaculum pusillum, Cicendia filiformis, Radiola linoides, Bellevalia trifoliata this paper represents their first record for inland zones since at present they were known for coastal areas only
Failure modes in deep-water carbonates and their impact for fault development: Majella Mountain, Central Apennines, Italy
No full textBrittle deformation of Triassic dolostones
No full textPreliminary results of an on-going project aimed at deciphering the micromechanics of brittle deformation of Triassic dolostones are here presented. Samples collected from large, trastensional high-angle faults (several 100’s m-throw) crosscutting the Mesozoic carbonates of the Neo Tethys (Campanian-Lucanian Platform) are investigated by mean of a detailed field structural survey, optical microscopy and SEM methodologies, and image analysis. The goal is to characterize in detail both composition and, mainly, texture of the cataclastic dolomitic rocks in order to assess the 3D structural architecture of the fault cores. Moreover, the present study addresses the relative timing of different mechanisms such as intergranular extensional crushing, chipping and shear fracturing, which all caused grain comminution during grain rolling and crushing. Finally, based upon the absolute thickness of key texture types recognized in the study cataclastic fault rocks, a simple model is assumed to compute the amount of overburden acting at time of deformation on the exhumed fault cores now days cropping out nearby the Basilicata-Campania border of southern Italy.
Study hand samples pertain to from well-exposed fault cores pertaining to high-angle faults oriented either NW-SE, parallel to the Apennine belt, or NE-SW, almost orthogonal to it. The faults crosscut the entire Meso-Cenozoic carbonate succession, and offset the low-angle thrust faults juxtaposing the aforementioned carbonates (fault hanging wall) against the Meso-Cenozoic, mixed carbonate-silicate Lagonegro succession (fault footwall). The amount of throw of individual high-angle faults was actually measured taking into account the displaced thrust faults as markers. Based upon large scale field mapping (1:10,000 scale) and 3D modelling of an about 100 km2 area (Move software), the NW-SE high-angle faults postdate the NE-SW ones, suggesting a different time of activity.
In the field, hand samples were selected based upon their distribution within the fault cores and, mainly, distance from main slip surfaces. Microscale analysis of 66 oriented fault rock samples shows that, mostly, the study cataclastic rocks are made up of dolomite. In a few cases, some small portions of silicate grains deriving from the Lagonegro succession (Scisti Silicei Fm.) are found. In order to characterize the main textural types, a great attention is been paid to the following parameters: 1) grain-matrix ratio; 2) grain sphericity; 3) grain roundness; 4) grain sorting. Moreover, by suing an automatic box-counting technique (Image-J software), the fractal dimension of selected samples was computed.
The preliminary results are consistent with four main textural types present within the study fault cores. The distinction is made on the basis of the grain-matrix ratio, which increases generally in the vicinity of the main slip surfaces. In particular, protocataclasites characterized by intense intergranular extensional fracturing are present adjacent to the fractured and fragmented dolomitic damage zones, whereas cataclasites and ultracataclasites in the inner portions of the fault cores. A negative correlation between grain-matrix and grain sphericity, roundness and sorting is documented for the latter rocks, which means that the more deformed ultracataclasites show more spherical and rounded smaller grains relative to cataclasites. The fourth type of texture, which is discontinuously present along main slip surfaces of the fault cores, consists on cataclasites and ultracataclasites cemented with calcite minerals.
On the basis of the aforementioned box-counting analysis, the three uncemented textural types show dissimilar D-values (fractal dimensions): D protoclasites = -1.82 (+ 1 sigma standard deviation 0.02); D cataclasites = - 1.72 (+ 0,05); D ultracataclasites = -1,56 (+ 0.04). This result shows therefore a positive correlation between D-value and fault maturity, and it might be helpful to quickly assess the degree of cataclasis in subsurface faults from analysis of cores recovered from exploration wells. Moreover, by taking into account only the cumulative thickness of the ultracataclastic bands present within the study faults, the result of the present study is consistent with the cores of the NW-SE faults being subjected to a lithostatic load about 6 times higher than those pertaining to the NE-SW faults. Ongoing 3D modelling of the study area will shed more lights on the slip distribution along individual faults to assess the relationship between ultracataclastic band thickness and fault intersection geometries
- …
