A new type of nanoelectrode, nanoporous platinum (NPt) electrode was prepared on aluminum oxide membrane by thermal evaporation deposition. The morphology, conductivity and electrocatalytic activity ...of NPt electrode were characterized and compared with those of nanofilm-Pt electrode through scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques, respectively. SEM images showed that “nanocavities” observed in NPt electrode were actually 2-dimensional enclosures by linked nanoparticles. It was different from the conventional arrays of “nanocavities” formed on homogeneous metal films. EIS data indicated that NPt electrode possesses higher conductivity. Compared with that on nanofilm-Pt electrode (14.05 Ω·cm2), the impedance spectrum on NPt electrode exhibits a semicircle portion with much smaller diameters (1.24 Ω·cm2 for NPt-100, 1.48 Ω·cm2 for NPt-200). Meanwhile, the response sensitivity of NPt electrode to O2 is 0.85 mA cm−2, which is larger than that of nanofilm-Pt electrode (0.54 mA cm−2). The largest catalytic current for nitric oxide (NO) was obtained in buffer with pH value of 9.4 while for Angeli's salt (AS) was obtained in buffer with pH value of 5.4. Additionally, electrocatalytic mechanisms of NPt electrode toward NO and AS were proposed, which indicating it depended on pH value of buffer solution.
The nanoporous platinum electrode (NPt) prepared on anodic aluminum oxide membrane exhibited large specific area and good electrocatalytic activity to reactive oxygen (O2) and nitrogen species (NO and nitroxyl). Among them, the catalytic sensitivity of NPt electrode to O2 is up to 0.85 mA cm−2. The largest catalytic current for NO was obtained in pH 9.4 buffer while for nitroxyl was obtained in pH 5.4 buffer solution. Display omitted
•A new type of nanoporous platinum (NPt) electrode was fabricated on porous aluminum oxide membrane at the first time.•Electrocatalytic mechanisms of NPt electrode toward NO and nitroxyl were proposed, which depended on pH value of buffer.•NPt electrode exhibited three times larger catalytic current to O2, NO and nitroxyl than those on nanofilm Pt electrode.
By the end of the twelfth century, the Byzantine genos was a politically effective social group based upon ties of consanguineous kinship, but, importantly, it was also a cultural construct, an idea ...that held very real power, yet defies easy categorization. This study explores the role and function of the Byzantine aristocratic family group, or genos , as a distinct social entity, particularly its political and cultural role, as it appears in a variety of sources in the tenth through twelfth centuries.
Whereas Picasso’s work in ceramics, wood and bronze is rather well known, the body of his sculptures in glass remains an object of little research. In fact, as a thorough analysis reveals, they ...rarely find mention in publications or catalogues on Picasso and seldom are included in exhibitions or retrospectives on the great Spanish artist. This may on the one hand be attributed to a still prevailing perception of glass as a medium for industrial, functional or everyday purposes—hence discounting the material in terms of artistic output—while on the other to controversies of authorship, related to the question of ideation versus creation. Unlike ceramics or bronze, the realisation of blown glass sculpture hinges on the involvement of the maestro vetraio as the mediator between thought and form—thus resulting in a distancing between artwork and artist conditioned by the nature of the medium. Against this background, the paper aims at a better understanding of Picasso’s vision of sculpture through an examination of his creations in the vitreous medium. On these grounds, a closer look at Picasso’s works in glass is meant to highlight his unique ‘hand’ in terms of idiom, line and form.
The Dosso degli Angeli reservoir is located along the coast of the Adriatic Sea, approximately 20km north of Ravenna, Italy, in the nearby of the Comacchio Lagoons. The field was discovered in 1968 ...and the production started in 1971. The production strongly decreased from 1998 to 2004 and suspended in 2004. In 2012 Eni, the oil company managing the reservoir, has planned to complete the exploitation of the residual reserves over the period from 2013 to 2023. An elasto-plastic FE model provided by Eni was used to measure the expected residual land subsidence, whose maximum value will amount to 2.8cm. In this work the environmental impact assessment of the expected land subsidence has been quantified on the lowlying coastland above the reservoir. Initially, the subsidence map has been used to quantify the displacement gradient ξ in correspondence of sensitive structures (bridges, pumping stations, lagoon embankments, historical buildings, power plants and a power lines) in order to assess the possible damages. Because the maximum ξ value amount to 1×10−5, i.e. 1mm over 100m, no damage is expected to the structures. Moreover, hydrological (HEC-HMS) and hydraulic (HEC-RAS) models have been used to evaluate the possible effects of the land subsidence on the efficiency of the main drainage networks used to keep dry the area, which is mainly located below the mean sea level. The results have shown a negligible loss of efficiency of the drainage system. The study allows concluding that land subsidence due to the residual gas production from the Dosso degli Angeli reservoir will not affects the environment, hydraulic safety, and infrastructures of the Comacchio Lagoons and the lowlying coastland surrounding this precious natural environment.
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•3D geomechanical model simulates the subsidence due to production of hydrocarbon reservoir.•Subsidence rates due to residual development of the reservoir is <2.8mm/year.•The expected displacement ranges between 10−6 and 10−5.•The effective subsidence capacity will not reduce the reclamation system efficiency.•Anthropogenic land subsidence is small compared to the actual land subsidence.
Thymus L. is of great interest in horticulture as ornamentals, spices, and medicinal plants, as well as in the extracts industry due to the richness in bioactive specialized metabolites. The natural ...hybrid T. × josephi-angeli Mansanet & Aguil. is produced in Spain, as its horticultural forms are very popular for domestic uses and gardening. However, its micropropagation and chemical composition have not been studied yet. Therefore, the main objective of this work was to develop a micropropagation procedure for T. × josephi-angeli, and to check whether the in vitro culture had an impact on the chemical profile of the plants. The results showed a high initiation rate (>91%) after two sterilization treatments were applied. Moreover, a micropropagation rate of around 21 new rooted explants per culture cycle was obtained in treatment M7 (Murashige and Skoog with 0.064 µM 6-(γ,γ-Dimethylallylamino)purine) when compared to the other 10 treatments performed. Acclimatization was successful in all three approaches tested (>75%), and all plants kept growing after 4 months of outdoor cultivation. Finally, 36 volatiles were identified, and the content of major compounds remained not statistically different in acclimatized plants when compared to the wild-type plants according to the analyses made by HS-SPME-GC/MS and SPME-GC/MS. This chemical stability points out the uniformity of the microplants and the suitability of the procedure applied in this study for T.×josephi-angeli horticultural production using in vitro techniques.
Salts of
N
-(het)aryl-
N
´-hydroxydiazene
N
-oxides were synthesized by the reaction of sodium nitrohydroxylaminate (Angeli´s salt) with the appropriate nitro compounds. The ion exchange reactions ...gave the corresponding copper and lead salts. The thermal stability of the synthesized salts was evaluated. Methylation of the synthesized salts afforded
N
-(het)aryl-
N
´-methoxydiazene
N
-oxides.
Hydroxamic acids have attracted significant attention due to their widespread use in applied chemistry. In this report, a modified Angeli–Rimini method has been achieved via the visible ...light-mediated catalytic transformation of a variety of heterocyclic, aromatic and aliphatic aldehydes
1a–j
to their corresponding hydroxamic acids
2a–j
in 81–93% yield. The unique ability of vitamin K
3
as a photoredox catalyst to expedite the development of completely new reaction mechanisms and to enable the construction of challenging carbon–nitrogen bonds has been investigated. It is shown for the first time that the vitamin K
3
and aldehyde are largely responsible for rapid in situ reduction of Ag
+
ions to catalytic photoluminescent Ag nanoclusters that possess a bandgap energy of 2.87 eV and are less than 2 nm in size. A mechanism for this reaction has been proposed and is supported by UV–Vis, TEM, ESI/MS, FT-IR,
1
H NMR and
13
C NMR analyses. The investigated method utilizes readily available reagents and produces the hydroxamic acids in high yields without the formation of side products, making it simple, practical and cost-effective.
Detailed geological mapping in 3-D supported by a LIDAR-derived DOM, sedimentologic and biostratigraphic analyses and 3-D numerical modelling are used to characterise the stratigraphic architecture ...of deep-water resedimented carbonate systems in the Gargano Peninsula (SE Italy). The base-of-slope succession spanning the upper Aptian to Danian p.p. was subdivided in five lithostratigraphic units that record the complex evolution and sedimentary dynamic along a segment of the Apulian Platform margin that was strongly influenced by syn-sedimentary tectonic activity. The characteristic location in a relay zone between the NW-SE trending platform margin and the E-W oriented Mattinata Fault System favoured the existence of a transtentional zone from the upper Aptian up to the end of the Cretaceous. The spatial distribution of the gravity flow deposits, the stratal geometries, the lateral facies changes, and the biostratigraphic data demonstrate that the base-of-slope systems were sourced by distinct platform blocks characterised by different slope profiles (abrupt to west and distally steepened to the north). In this context, the nature and origin of the resedimented carbonate material were controlled by the fracturation of the margin, the response of the carbonate factory to relative sea level changes but were also strongly influenced by the slope profile. This study demonstrates the relevance of combining traditional field work with numerical tools to improve the understanding of ancient sedimentary systems, notably by mapping the stratal architecture and lithologies in continuity and at various scales (on DOMs), and by reconstructing the paleo-topographies in 3-D.
One-electron oxidation of acetohydroxamic acid (aceto-HX) initially gives rise to nitroxyl (HNO), which can be further oxidized to nitric oxide (NO) or react with potential biological targets such as ...thiols and metallo-proteins. The distinction between the effects of NO and HNO in vivo is masked by the reversible redox exchange between the two congeners and by the Janus-faced behavior of NO and HNO. The present study examines the ability of aceto-HX to serve as an HNO donor or an NO donor when added to Escherichia coli and Bacillus subtilis subjected to oxidative stress by comparing its effects to those of NO and commonly used NO and HNO donors. The results demonstrate that: (i) the effects of NO and HNO on the viability of prokaryotes exposed to H2O2 depend on the type of the bacterial cell; (ii) NO synergistically enhances H2O2-induced killing of E. coli, but protects B. subtilis depending on the extent of cell killing by H2O2; (iii) the HNO donor Angeli׳s salt alone has no effect on the viability of the cells; (iv) Angeli׳s salt synergistically enhances H2O2-induced killing of B. subtilis, but not of E. coli; (v) aceto-HX alone (1–4mM) has no effect on the viability of the cells; (vi) aceto-HX enhances the killing of both cells induced by H2O2 and metmyoglobin, which may be attributed in the case of B. subtilis to the formation of HNO and to further oxidation of HNO to NO in the case of E. coli; (vii) the synergistic activity of aceto-HX on the killing of both cells induced by H2O2 alone does not involve reactive nitrogen species. The effect of aceto-HX on prokaryotes under oxidative stress is opposite to that of other hydroxamic acids on mammalian cells.
•HNO has no effect on the viability of B. subtilis and E. coli.•HNO enhances H2O2-induced killing of B. subtilis, but not of E. coli.•Aceto-HX has no effect on the viability of B. subtilis and E. coli.•Aceto-HX enhances the killing of both cells induced by H2O2 and MetMb.•A plausible synergic mechanism involves the formation of reactive nitrogen species.
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