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Hardly a few people manage to escape big fears without dying [of them]; not so with pains. This statement captures Cardano's understanding of the difference between mental and physical pain. As a physician with a lifelong history of anxiety and alienation, Cardano inquired ceaselessly into the nature of the delicate interaction between the two kinds of pain. It was his belief that the subtle nature of mental suffering makes it difficult, if not impossible, to identify, name, and give a meaning to those powerful emotions which cause our inner turmoil. Unable to be 'named' and 'signified', mental pain eludes understanding and thereby deprives the mind of its identity as a locus of sense. In the experience of physical pain, conversely, the mind can easily decode the signs in the body, keeping its mastery over sense-perception, the imagination, and desire. For this reason, Cardano believed, many people afflicted by sorrow and grief (including himself) find solace in physical pain, which in its purest form (i.e. not accompanied by emotions) is even able to enhance our cognitive potential. [ABSTRACT FROM AUTHOR]

The article deals with how the Greek word "eidola" or images lose their traditional status as images and become sounds in Italian polymath Gerolamo Cardano's "Somniorum Synesiorum Libri IIII published in 1562. It discusses the conception of eidola in the philosophy of the Greek philosopher Plato. It also tackles Cardano's preoccupation with prophetic dreams, dividing dreams into heightened perceptions and dream-images.

This article explores Marsilio Ficino's interpretation of Plotinus's notion of tutelary daemon, as found in Enneads III.4. While Plotinus considered external daemons as philosophically insignificant and described one's personal daemon as the highest part of one's soul, Ficino placed great emphasis on the existence of outer daemonic entities which continuously interact with human beings. As a consequence, for Plotinus the soul's tutelary daemon corresponded to man's capability for intellectual knowledge, that is, to his ability to become emancipated from the material world, which, from a Platonic point of view, was made of appearances. Ficino, by contrast, tends to identify the soul's daemonic power with the faculty which he saw as the gateway for the action of external entities: the imagination. The imagination – like a mirror – reflects and retains images of other levels of life and acts as the surface on which external daemons project the forms of their own imagining. Ficino provides a complex account of the relationships between the soul and various layers of daemonic interventions, in which he combines Plotinus's view on personal daemons with elements coming from later forms of daemonology, such as that of Porphyry, Iamblichus, Synesius and Proclus. [ABSTRACT FROM PUBLISHER]

Abstract: We report the synthesis, characterization and relaxometric study of ferrofluids based on iron oxide, with potential for use as magnetic resonance imaging (MRI) contrast agents (CAs). The effect of different cost-effective, water-based surface modification approaches which can be easily scaled-up for the large scale synthesis of the ferrofluids has been investigated. Surface modification was achieved by silanization, and/or coating with non-toxic commercial dispersants (a lauric polysorbate and a block copolymer with pigment affinic groups, namely Tween 20 and Disperbyk 190) which were added after or during iron oxide nanoparticle synthesis. It was observed that all the materials synthesized functioned as negative contrast agents at physiological temperature and at frequencies covered by clinical imagers. The relaxometric properties of the magnetic nanoparticles were significantly improved after surface coating with stabilizers compared to the original iron oxide nanoparticles, with particular reference to the silica-coated magnetic nanoparticles. The results indicate that the optimization of the preparation of colloidal magnetic ferrofluids by surface modification is effective in the design of novel contrast agents for MRI by enabling better or more effective interaction between the coated iron oxide nanoparticles and protons present in their aqueous environment. [Copyright &y& Elsevier]

Abstract: The structural properties of CoFe2O4–SiO2 highly porous nanocomposite aerogels have been investigated by X-ray Absorption Spectroscopy and Transmission Electron Microscopy techniques. The aerogels are obtained by supercritical drying of composite gels obtained using a two step procedure where fast gelation is achieved using urea in the second step. The formation of CoFe2O4 nanocrystals in the silica matrix begins after calcination at 750°C of the parent aerogel and is complete after calcination at 900°C, while the high porosity of the sample is mostly retained. [Copyright &y& Elsevier]

Extended X-ray absorption fine structure and X-ray absorption near-edge structure techniques were used to study in detail the structural characteristics of FeCo−Al2O3 nanocomposite xerogels and aerogels. The formation of bcc FeCo alloy, which cannot be assessed unambiguously by X-ray diffraction, dispersed within the alumina matrix was evidenced in the final samples obtained by heat treatment at 800 °C in reducing atmosphere. Aerogel samples reduced below 800 °C still present a fraction of oxidized metal together with the bcc alloy. The investigation of the xerogels and aerogels calcined at increasing temperature indicates that Fe(III) and Co(II) ions are present and they are located in the tetrahedral sites of the spinel structure of the matrix (γ-Al2O3); moreover, the precursor of the spinel is more ordered in the aerogel sample than the xerogel sample. [ABSTRACT FROM AUTHOR]

[Display omitted] • CNT supported Ru single atoms have been associated to Ru, Pd and Ni particles. • Hydrogen spillover induced a cooperative catalysis between supported Pd and Ni particles and Ru single atoms. • The RuNi/CNT catalyst contains a cocktail of catalytic species including isolated Ru single atoms and Ru single atoms on Ni particles. • The RuNi/CNT catalyst shows much better performances in terms of activity and selectivity compared to the monometallic systems. • DFT calculations revealed that the active species is a Ru SA @Ni NP single atom alloy. Reaching high selectivity at high conversion and high rate in the industrially important selective hydrogenation of α,β-unsaturated aldehydes is a challenging task. Among current approaches reported in the literature, high selectivity towards the unsaturated alcohol or saturated aldehyde is generally achieved at the expense of activity. The use of bimetallic systems can lead either to selectivity or to activity enhancement, but generally not to both. Herein, we show that, for cinnamaldehyde hydrogenation, combining Ni nanoparticles (Ni NP) and Ru single atoms (Ru SA) on CNTs allows improvement of the hydrocinnamaldehyde selectivity, while obtaining a remarkable activity. The STY of Ru SA -Ni NP /CNT is approximately 60 times higher than that of the Ru SA /CNT and 10 times higher than that of the Ni NP /CNT. Importantly, the resulting catalyst shows 94% selectivity at 99% conversion and a good stability in flow. Insights into the cooperative "cocktail"-type catalysis between Ni NP and Ru SA were revealed from density functional theory calculations. [ABSTRACT FROM AUTHOR]

Pd/C catalysts are widely used for hydrogenation reactions in the chemical industry. One of the reasons for their high activity is the ability of Pd nanoparticles (PdNP) to dissociate H2 and promote H‐spillover. Nevertheless, for selective hydrogenation unpromoted Pd/C catalysts show disappointing results. The use of supported Pd single atom (PdSA) catalysts permits to achieve high selectivity. However, PdSA show low activity because they have difficulty in activating H2. A cooperative catalysis between PdNP and PdSA operates for the hydrogenation of alkenes thanks to the H‐spillover, which makes it possible to obtain active isolated PdSA−H species. Here, we present experimental and computational results obtained for phenylacetylene hydrogenation on Pd/CNT catalysts showing different PdSA/PdNP ratios. Tuning this ratio allows doubling the activity while reaching high selectivity to styrene at high conversion. DFT calculations suggest that the first coordination sphere of PdSA has a pronounced effect on their reactivity. [ABSTRACT FROM AUTHOR]

Rare-earth orthoferrite RFeO3 materials have recently attracted great attention for their intriguing technological potential. Among these materials, SmFeO3 holds great promise, not only for its excellent physical properties (fast magnetic switching, spin reorientation, and magnetization reversal), but also for its potential ferroelectric properties, which have been recently under debate. Here, we focus our attention on the T-dependent Zero Field Cooled and Field Cooled magnetization properties of micrometer scale crystals of SmFeO3 obtained by annealing methods. We report the observation of an enhanced magnetic transition at a temperature of approximately 139 K. From literature bulk susceptibility measurements, it has been suggested that below the temperature of about 140K, 3+ moments begin to order antiparallel to the Fe-moments due to antiferromagnetic f-d exchange interactions. We attribute the observed transition to compensation effects induced by the appearance of long range ordering in 3+ spins. The magnetic-nature of the observed transition is confirmed by additional temperature dependent XRD analysis, which did not show structural changes in the samples in the same temperature range (from 298K to 100K). Due to residual small fractions of ferromagnetic α-Fe from the sample-growth, possible interactions between the magnetic moment of α-Fe and the SmFeO3 crystals at the compensation temperature cannot be excluded and could be at the origin of the enhanced magnetic signal reported in this work. [ABSTRACT FROM AUTHOR]

In this work, nanocomposites constituted of FeCo alloy nanoparticles dispersed on a highly porous silica aerogel have been designed as catalysts for low temperature Fischer-Tropsch synthesis. The catalysts were characterized by XRD, TEM, N physisorption and SEM analysis. A high catalytic activity with CO conversions up to 95 % has been obtained, with enhanced selectivity for the C-C hydrocarbons. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Abstract: The influence of PtRu bimetallic particle size and composition on cinnamaldehyde selective hydrogenation has been investigated for the first time using well-defined catalysts based on carbon nanotubes support. Very high selectivity towards cinnamyl alcohol together with high activity have been obtained provided a high temperature treatment of the catalyst is performed. HRTEM, WAXS and EXAFS analyses permit us to conclude that the remarkable influence of this high temperature treatment on both activity and selectivity arises from different phenomena. First, a particle size and a structural effect have been evidence that permits to increase the selectivity. WAXS and EXAFS point the formation of alloyed PtRu nanoparticles. Second, the heat treatment allows the removal of oxygenated groups from CNT surface. This may increase the cinnamaldehyde adsorption capacity and decrease the activation barrier for diffusion of substrate and product on the CNT surface, thus contributing to an increase in the activity. [Copyright &y& Elsevier]

Silica alcogels were synthetized by the sol–gel polymerization of tetraethylorthosilicate in acid media. Conventional and supercritical drying was performed in order to obtain xerogels and aerogels. Different process parameters of the supercritical drying were altered in order to control the texture of the resulting gel. The texture and the structural evolution of xero- and aerogels were studied by thermogravimetric-differential thermal analysis, Fourier-transform infrared spectroscopy, transmission electron microscopy and N2 physisorption at 77 K. 29Si magic angle spinning nuclear magnetic resonance experiments on silica samples were used to resolve various silicon local environments. Hydrophilic microporous xerogels and hydrophobic micro- or mesoporous silica aerogels were obtained, whose microscopic structure is very similar. However, the samples obtained by different drying procedures exhibit a different structural evolution with temperature. [Copyright &y& Elsevier]

Surfactant-mediated chemical routes allow one to synthesize highly engineered shape- and size-controlled nanocrystals. However, the occurrence of capping agents on the surface of the nanocrystals is undesirable for selected applications. Here, a novel approach to the production of shape-controlled nanocrystals which exhibit high thermal stability is demonstrated. Ceria nanocubes obtained by surfactant-mediated synthesis are embedded inside a highly porous silica aerogel and thermally treated to remove the capping agent. Powder X-ray Diffraction and Scanning Transmission Electron Microscopy show the homogeneous dispersion of the nanocubes within the aerogel matrix. Remarkably, both the size and the shape of the ceria nanocubes are retained not only throughout the aerogel syntheses but also upon thermal treatments up to 900 °C, while avoiding their agglomeration. The reactivity of ceria is measured by in situ High-Energy Resolution Fluorescence Detected - X-ray Absorption Near Edge Spectroscopy at the Ce L 3 edge, and shows the reversibility of redox cycles of ceria nanocubes when they are embedded in the aerogel. This demonstrates that the enhanced reactivity due to their prominent {1 0 0} crystal facets is preserved. In contrast, unsupported ceria nanocubes begin to agglomerate as soon as the capping agent decomposes, leading to a degradation of their reactivity already at 275 °C. [ABSTRACT FROM AUTHOR]

We report a novel investigation on the relationship between magnetic-ordering and graphitic-structure in highly-oriented-pyrolytic-graphite (HOPG). By employing orientation-dependent-X-ray-diffraction, Raman-spectroscopy and temperature-dependent-superconductive-quantum-interference-device (T-SQUID) we examined the presence of ferromagnetic- and superconductive-ordering in HOPG systems with 1) disordered (HOPG1, containing carbon-vacancy-rich weak-Bernal-stacking and Moiré-superlattices with θ misfit ∼ 0.5°) and 2) ordered (HOPG2, containing higher-degree of Bernal-stacking and Moiré-superlattices with θ misfit ∼ 0.5°, 0.8°, 11°) graphitic-layer-arrangement. A perfect-HOPG is expected to exhibit a diamagnetic-response to an applied-magnetic-field. Instead, additional 1) ferromagnetic-signals presenting a characteristic width-enhancement with the field increasing in HOPG1 and 2) complex butterfly-shaped ferromagnetic signals in HOPG2, are demonstrated. Temperature-dependent-magnetometry evidenced further the presence of randomly oriented ferromagnetic clusters originating from topological disorder in both HOPG1 and HOPG2. These magnetic signals were explained on the basis of the percolative-type model. [ABSTRACT FROM AUTHOR]

We show a novel chemical vapour deposition (CVD) approach, in which the large-scale fabrication of ferromagnetically-filled cm-scale buckypapers is achieved through the deposition of a mesoporous supported catalyst (SBA-16) on a silicon substrate. We demonstrate that SBA-16 has the crucial role of promoting the growth of carbon nanotubes (CNTs) on a horizontal plane with random orientation rather than in a vertical direction, therefore allowing a facile fabrication of cm-scale CNTs buckypapers free from the onion-crust by-product observed on the buckypaper-surface in previous reports. The morphology and composition of the obtained CNTs-buckypapers are analyzed in detail by scanning electron microscopy (SEM), Energy Dispersive X-ray (EDX), transmission electron microscopy (TEM), high resolution TEM (HRTEM), and thermogravimetric analysis (TGA), while structural analysis is performed by Rietveld Refinement of XRD data. The room temperature magnetic properties of the produced buckypapers are also investigated and reveal the presence of a high coercivity of 650 Oe. Additionally, the electrochemical performances of these buckypapers are demonstrated and reveal a behavior that is compatible with that of a pseudo-capacitor (resistive-capacitor) with better performances than those presented in other previously studied layered-buckypapers of Fe-filled CNTs, obtained by pyrolysis of dichlorobenzene-ferrocene mixtures. These measurements indicate that these materials show promise for applications in energy storage systems as flexible electrodes. [ABSTRACT FROM AUTHOR]

Copper-based nanoparticles, supported on either a silica aerogel or cubic mesostructured silicas obtained by using two different synthetic protocols, were used as catalysts for the water gas shift reaction. The obtained nanocomposites were thoroughly characterised before and after catalysis through nitrogen adsorption-desorption measurements at −196 °C, TEM, and wide- and low-angle XRD. The samples before catalysis contained nanoparticles of copper oxides (either CuO or Cu2O), whereas the formation of metallic copper nanoparticles, constituting the active catalytic phase, was observed either by using pre-treatment in a reducing atmosphere or directly during the catalytic reaction owing to the presence of carbon monoxide. A key role in determining the catalytic performances of the samples is played by the ability of different matrices to promote a high dispersion of copper metal nanoparticles. The best catalytic performances are obtained with the aerogel sample, which also exhibits constant carbon monoxide conversion values at constant temperature and reproducible behaviour after subsequent catalytic runs. On the other hand, in the catalysts based on cubic mesostructured silica, the detrimental effects related to sintering of copper nanoparticles are avoided only on the silica support, which is able to produce a reasonable dispersion of the copper nanophase. [ABSTRACT FROM AUTHOR]

The recent observations of unusual superconductive effects in highly oriented pyrolytic graphite (HOPG) and twisted bi-layer, tri-layer and multilayer graphene materials have attracted an important attention. In this work we present a novel investigation on the relationship between structural ordering and magnetism in HOPG. Orientation dependent X-ray diffraction and temperature dependent magnetometry allowed for the identification of those HOPG samples exhibiting a long-range ordering along the c-axis. ZFC and FC magnetic curves acquired from T ~ 2 K to 300 K revealed a significant temperature-dependent variation of the diamagnetic component. By analyzing the ZFC/FC magnetic-curves (through magnetic moment subtraction methods) we identify the presence of a weak magnetic transition in the T range from 200 K to 2 K. The possible origin of the observed magnetization-trend is interpreted in relation to contributions arising from 1) disorder-rich locally-twisted-interfaces and 2) those internal graphitic sublattices exhibiting negative thermal expansion. Interestingly, magnetization against field measurements acquired at T ~ 50 K (max. field of 150 Oe) revealed the presence of a weak ferromagnetic-like hysteresis. Disappearance of the unusual ZFC/FC signal-splitting was instead found in those magnetic curves acquired from other HOPG samples with higher degree of disorder (short-range-ordering along the c-axis). This second category of samples was found to exhibit a disorder-mediated re-entrant spin-glass-like ferromagnetic behavior. [Display omitted] • We present a novel investigation on HOPG samples exhibiting a long-range ordering along the c-axis. • ZFC and FC magnetic curves from T ~ 2 K to 300 K revealed a temperature-dependent variation of the diamagnetic component. • We identify the presence of a weak magnetic transition in the T range from 200 K to 2 K. • Disappearance of the unusual signals-splitting was found in HOPG samples with higher degree of disorder. [ABSTRACT FROM AUTHOR]

The structure of the iron oxyhydroxide called feroxyhyte (δ-FeOOH), which shows an elusive X-ray powder diffraction pattern, has been represented so far using models describing a mean structure based on the crystalline network of the iron(III) oxide hematite (α-Fe 2 O 3 ). In this paper, a novel description of the mean structure of feroxyhyte is presented, which is based on the structure of the thermodynamically stable iron oxyhydroxide goethite. Starting from different local arrangements present in the goethite network, a mean structural model is determined which shows an X-ray powder diffraction pattern almost coincident with previous studies. This outcome enables to integrate the structure of feroxyhyte among those of other well characterized iron oxyhydroxides. [ABSTRACT FROM AUTHOR]

Highlights: [•] SBA-16 based monoliths containing Fe/Co nanophases were prepared by sol–gel. [•] Monoliths are stable upon calcination at 500°C and reduction at 800°C. [•] Superparamagnetic fcc Co–SBA-16 nanocomposites can be obtained. [ABSTRACT FROM AUTHOR]

A mesoporous ordered cubic Im3m silica (SBA-16) characterized by a three dimensional cage-like structure of pores was used as a host matrix for the preparation of a series of FeCo-SiO2 nanocomposites with different alloy loading and composition by the wet impregnation method. The mesoporous structure of the SBA-16-type support, prepared according to a versatile sol-gel templated synthetic method, which makes use of n-butanol as a co-surfactant, is stable during the treatments necessary to obtain the final nanocomposites, as pointed out by low-angle X-Ray diffraction, transmission electron microscopy, and N2 physisorption at 77 K. Wide-angle X-ray diffraction shows that upon reduction at 800 °C, FeCo nanocrystals (6-7 nm) with the typical bcc structure are formed and energy-dispersive X-ray spectroscopy analysis, performed by scanning transmission electron microscopy on one of the samples, shows that the Fe/Co atomic ratio in the alloy nanoparticles is very close to the expected value of two. Electron tomography was used for the first time to gain evidence on the highly interconnected mesoporous structure of SBA-16 and the arrangement of the nanoparticles within the matrix. It was found that spherical alloy nanocrystals with narrow size distribution are homogeneously distributed throughout the mesoporous matrix and that the resulting FeCo-SiO2 nanocomposite material displays superparamagnetic behavior with high strength dipolar interactions, as expected for particles with a large magnetic moment. [ABSTRACT FROM AUTHOR]

series of novel nanocomposites constituted of FeCo nanoparticles dispersed in an ordered cubic Im3m mesoporous silica matrix (SBA-16) have been successfully synthesized using the wet impregnation method. SBA-16, prepared using the non-ionic Pluronic 127 triblock copolymer as a structure-directing agent, is an excellent support for catalytic nanoparticles because of its peculiar three-dimensional cage-like structure, high surface area, thick walls, and high thermal stability. Low-angle X-ray diffraction, N physisorption, and transmission electron microscopy analyses show that after metal loading, calcination at 500 °C, and reduction in H flux at 800 °C, the nanocomposites retain the well-ordered structure of the matrix with cubic symmetry of pores. FeCo alloy nanoparticles with spherical shape and narrow size distribution (4-8 nm) are homogeneoulsy distributed throughout the matrix and they seem in a large extent to be allocated inside the pores. [ABSTRACT FROM AUTHOR]

Abstract: Mesoporous silica films with controlled porosity were utilized as the host matrices to prepare FeCo–SiO2 nanocomposites through an impregnation process. The mesoporous silica films were first impregnated with a solution containing Co(II) and Fe(III) ions and then submitted to a reduction treatment under H2 flow. FeCo nanocrystals growth took place inside the mesopores, and their monodisperse size was dictated only by the size of the mesopores. We illustrate this process by the use of two different silica film matrices having different pore size and mesophase symmetry as the templates for the growth of FeCo alloy nanocrystals. The films and the nanocomposite samples were investigated by grazing-incidence small-angle X-ray scattering, X-ray diffraction and transmission electron microscopy. Unimpregnated mesoporous silica samples before and after the same thermal reduction treatment were also studied in order to investigate the mesopore structure variation upon the reduction treatment. [Copyright &y& Elsevier]

CuFe2O4 is an example of ferrites whose physico-chemical properties can vary greatly at the nanoscale. Here, sol-gel techniques are used to produce CuFe2O4-SiO2 nanocomposites where copper ferrite nanocrystals are grown within a porous dielectric silica matrix. Nanocomposites in the form of both xerogels and aerogels with variable loadings of copper ferrite (5 wt%, 10 wt% and 15 wt%) were synthesized. Transmission electron microscopy and X-ray diffraction investigations showed the occurrence of CuFe2O4 nanoparticles with average crystal size ranging from a few nanometers up to around 9 nm, homogeneously distributed within the porous silica matrix, after thermal treatment of the samples at 900 °C. Evidence of some impurities of CuO and α-Fe2O3 was found in the aerogel samples with 10 wt% and 15 wt% loading. DC magnetometry was used to investigate the magnetic properties of these nanocomposites, as a function of the loading of copper ferrite and of the porosity characteristics. All the nanocomposites show a blocking temperature lower than RT and soft magnetic features at low temperature. The observed magnetic parameters are interpreted taking into account the occurrence of size and interaction effects in an ensemble of superparamagnetic nanoparticles distributed in a matrix. These results highlight how aerogel and xerogel matrices give rise to nanocomposites with different magnetic features and how the spatial distribution of the nanophase in the matrices modifies the final magnetic properties with respect to the case of conventional unsupported nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract: Highly ordered silica and hybrid organic–inorganic membranes have been obtained through a slow and controlled solvent evaporation in the presence of a triblock copolymer as the structure-directing agent. Crack-free mesostructured membranes of large dimensions have been prepared. The mesophase is self-organized into a periodic cubic structure, , and consists of macroscopic mesostructured domains that maintain the out-of-plane order throughout the material. After calcination at 350°C the membranes remain transparent even though they break in fragments of some centimeters. Different techniques have been employed to characterize the mesoporous materials: small angle X-ray scattering (SAXS) using synchrotron radiation and transmission electron microscopy to study the porous structure, Fourier transform infrared spectroscopy (FTIR) in vacuum at different partial pressures to investigate the nature of the pore surface. SAXS analysis has been used to map the whole membrane, revealing some differences in the pore organization that can be attributed to a gradient in the evaporation rate. The infrared measurements at different partial pressures have elucidated the mechanism of water adsorption–desorption on the pore surface. The changes of the FTIR spectra with different partial pressure have demonstrated that the pore surface is covered by a layer of molecular water that is hydrogen bonded to silanol species. [Copyright &y& Elsevier]

A comprehensive study of iron oxide nanocrystal growth through non-hydrolitic, surfactant- mediated thermal reaction of iron pentacarbonyl and an oxidizer has been conducted, which includes size control, anisotropic shape evolution, and crystallographic phase transition of monodisperse iron oxide colloidal nanocrystals. The reaction was monitored via in situ UV-vis spectroscopy, taking advantage of the color change accompanying the iron oxide colloid formation, allowing measurement of the induction time for nucleation. Features of the synthesis such as the size control and reproducibility are related to the occurrence of the observed delayed nucleation process. As a separate source of iron and oxygen is adopted, phase control could also be achieved by sequential injections of oxidizer. [ABSTRACT FROM AUTHOR]