Poly(3,4-ethylenedioxythiophene)/Au-nanoparticles composite as electrode coating suitable for electrocatalytic oxidation

Composite materials consisting of poly(3,4-ethylenedioxythiophene) including Au nanoparticles, encapsulated by citrate anions, have been firmly deposited on an electrode surface through a simple method, taking advantage of the interaction between Au metal and thiophene polymeric backbone. A series of similar electrode coatings, also including different amounts of nanoparticles inside, has been characterised in terms of thickness and surface morphology, through different microscopic techniques. The electrocatalytic properties have been studied with respect to the oxidation of glucose in alkaline media, which is prevented from occurring on the pure organic material.     

Enantioselective Gas Chromatography with Derivatized Cyclodextrins in the Flavour and Fragrance Field

This article deals with enantioselective gas chromatography (Es-GC) utilizing cyclodextrin derivatives as chiral stationary phases (CSPs) for chiral recognition in the flavour and fragrance field. It consists of two main parts. The first one concerns cyclodextrins and their use in Es-GC, and it deals with their introduction and evolution as CSPs in GC, together with some theoretical aspects involved with enantiomeric separation and their consequent influence on routine chiral recognition. The second part reports on the strategy of chiral recognition in routine analysis with cyclodextrin derivatives as CSP, illustrated with examples from the authors’ everyday experiences. This part describes how to identify enantiomers or to measure their excess or ratio determination in complex mixtures; in particular, it discusses the opportunities offered by multidimensional and fast GC techniques, the role of mass spectrometry, and the application of total analysis systems to chiral recognition.     

Evaluation of the effects of silver nanoparticles on Danio rerio cornea: Morphological and ultrastructural analysis

Although in recent years there has been intensification in the use of nanoparticles (NPs) for the production of many commercial products, few studies have been carried out to assess the risks associated with its use. Among the most used NPs, silver nanoparticles (AgNPs) have a preponderant position as they have various applications. In this study, 40 adult zebrafish were exposed to increasing concentrations of AgNPs (8, 45, and 70 μg/L) for 30 days to evaluate the effects on eyes after chronic exposure to AgNPs with an average diameter of 50 nm. From the morphological and ultrastructural analysis performed, no alteration or lesions of the corneal epithelium were detected.     

Ni‐Ti Codoped Hibonite Ceramic Pigments by Combustion Synthesis: Crystal Structure and Optical Properties

Hibonite (CaAl₁₂O₁₉, space group [s.g.] P6₃/mmc) has the structural formula A^[XII]M1^[VI] M2^[V]M3₂^[IV]M4₂^[VI]M5₆^[VI]O₁₉, where Ca is 12‐fold coordinated at site A and Al³⁺ ions are distributed over five different sites: three distinct octahedra [M1 (point symmetry D_3d), M4 (C_3v) and M5 (C_s)], the M3 tetrahedron (C_3v), and the unusual fivefold coordinated trigonal bipyramid M2 (D_3h). Hibonite is able to accommodate a wide range of ions with different valence and coordination, making its structure a promising ceramic pigment. One of the main challenges is to understand and control incorporation mechanisms and the threshold of chromophores solubility. It is known that M²⁺ ions tend to be hosted at the M3 site, while M⁴⁺ ions are preferentially accommodated at the M4 site: the introduction of divalent ions might be promoted by the associated incorporation of tetravalent cations, which ensure the lattice electroneutrality and are ordered over the M4 face‐sharing octahedral dimers. In this work, the mechanism of the coupled substitution 2Al³⁺→(Ni²⁺+Ti⁴⁺) was investigated by combining X‐ray powder diffraction and diffuse reflectance spectroscopy techniques. Hibonite turquoise pigments with increasing Ni+Ti doping (CaAl_12?2xNi_xTi_xO₁₉ where x = 0.1?2.0 apfu) were prepared by combustion synthesis, utilizing a fuel mixture (urea, glycine, β‐alanine) set up according to their compatibility with metal nitrates used as raw materials. The ignition temperature of combustion reaction was 400°C, but samples underwent an additional annealing at 1200°C. Samples up to x = 0.4 are monophasic; for higher doping, hibonite is the main component accompanied by growing percentages of spinel and perovskite phases. The Ni and Ti addition induced a regular increase in the hibonite unit‐cell parameters until x = 1.0, that is proportional to the amount and difference in ionic radii of dopants. In particular, an elongation of the 〈M–O〉 bond distances of both M3 and M4 sites was observed. In terms of optical parameters, Ni²⁺ is preferentially incorporated in tetrahedral coordination, up to 0.3 apfu at the M3 site, and at the M4 octahedron as well (up to 0.19 apfu). The crystal field strength of fourfold coordinated Ni²⁺ is regularly decreasing, implying an elongation of the local Ni–O bond that is coherent with the volume increasing from AlO₄ to NiO₄ tetrahedra registered by XRD. Ti⁴⁺ ions are accommodated at both the M2 and M4 octahedra which expand proportionally to the amount of dopants. Pigment purity and color strength vary with doping depending on the multistep mechanism of Ni and Ti incorporation in the hibonite lattice.     

In situ synthesis of metal oxides in carbon nanotube arrays and mechanical properties of the resulting structures

In the past, aligned arrays of carbon nanotubes (CNTs) have been observed to exhibit a foam-like dissipative response in compression, garnering attention for possible mechanical applications. Nanoparticles have previously been integrated with graphitic materials for electrochemical applications. Here, we synthesize nanoparticles of SnO₂ and MnO₂ in the interstices of aligned arrays of CNTs without altering the ordered structure of the arrays, and we characterize their mechanical response. We report that CNT arrays with embedded particles present superior energy dissipation relative to unmodified CNT arrays. In addition, energy dissipation, strain recovery, and structural failure (observed after repeated loading) depend on particle type (SnO₂ versus MnO₂).     

Blue Cone Monochromatism with Foveal Hypoplasia Caused by the Concomitant Effect of Variants in OPN1LW/OPN1MW and GPR143 Genes

Blue cone monochromatism (BCM) is an X-linked recessive cone dysfunction disorder caused by mutations in the OPN1LW/OPN1MW gene cluster, encoding long (L)- and middle (M)-wavelength-sensitive cone opsins. Here, we report on the unusual clinical presentation of BCM caused by a novel mutation in the OPN1LW gene in a young man. We describe in detail the phenotype of the proband, and the subclinical morpho-functional anomalies shown by his carrier mother. At a clinical level, the extensive functional evaluation demonstrated in the proband the M/L cone affection and the sparing of S-cone function, distinctive findings of BCM. Interestingly, spectral-domain optical coherence tomography showed the presence of foveal hypoplasia with focal irregularities of the ellipsoid layer in the foveal area, reported to be associated with some cases of cone-rod dystrophy and achromatopsia. At a molecular level, we identified the novel mutation c.427T > C p.(Ser143Pro) in the OPN1LW gene and the common missense mutation c.607T > C (p.Cys203Arg) in the OPN1MW gene. In addition, we discovered the c.768-2_769delAGTT splicing variant in the GPR143 gene. To our knowledge, this is the first case of foveal hypoplasia in a BCM patient and of mild clinical affection in a female carrier caused by the concomitant effect of variants in OPN1LW/OPN1MW and GPR143 genes, thus as the result of the simultaneous action of two independent genetic defects.     

Molecular Biology of Atherosclerotic Ischemic Strokes

Among the causes of global death and disability, ischemic stroke (also known as cerebral ischemia) plays a pivotal role, by determining the highest number of worldwide mortality, behind cardiomyopathies, affecting 30 million people. The etiopathogenetic burden of a cerebrovascular accident could be brain ischemia (~80%) or intracranial hemorrhage (~20%). The most common site when ischemia occurs is the one is perfused by middle cerebral arteries. Worse prognosis and disablement consequent to brain damage occur in elderly patients or affected by neurological impairment, hypertension, dyslipidemia, and diabetes. Since, in the coming years, estimates predict an exponential increase of people who have diabetes, the disease mentioned above constitutes together with stroke a severe social and economic burden. In diabetic patients after an ischemic stroke, an exorbitant activation of inflammatory molecular pathways and ongoing inflammation is responsible for more severe brain injury and impairment, promoting the advancement of ischemic stroke and diabetes. Considering that the ominous prognosis of ischemic brain damage could by partially clarified by way of already known risk factors the auspice would be modifying poor outcome in the post-stroke phase detecting novel biomolecules associated with poor prognosis and targeting them for revolutionary therapeutic strategies.     

Studying the heterogeneity of European higher education institutions

Scientometrics - The heterogeneity of the Higher Education (HE) Institutions is one of the main critical issues in the assessment of their performance. This paper adopts a multi-level and...