During the two last decades, the interest in the role of Vitamin D (VD) in allergic disease has increased. Apart from the well-known actions of VD in bone metabolism, recent studies suggested its ...possible role as an immune-modulator in allergy.
This study, conducted over the Italian territory, evaluated the possible correlations between VD serum level and diagnosed allergic diseases (rhinitis / asthma, food allergy, atopic dermatitis). Thus, VD was assessed in patients with physician-diagnosed allergic diseases.
The study was carried out in hospital- and private practice-based setting between October 2012 and March 2013, and 18 Centers participated. Only adult patients, with at least one positive skin prick test were included. The diagnostic procedures and the data collection were standardized among the centers. VD levels were assayed by the same laboratory test.
Three hundred and nine patients were enrolled (132 male, mean age 37.5 ± 17 years). Of them, 40% reported a positive family history for allergies (asthma / rhinitis). Rhinitis plus asthma was present in 47% of patients, atopic dermatitis in 15%, and a consistent clinical history of food allergy associated with positive skin tests was present in 25% of subjects. There was no significant association between VD level and age, sex, family history, rhinitis, or food allergy. VD levels were overall lower in patients with asthma and rhinitis, but without statistical significance. A significant difference in VD levels was detected between patient with or without atopic dermatitis. VD was not related to seasonal allergens, whereas a significant negative correlation was seen for house dust mite and dog dander.
Our data, derived from a cross-sectional study involving only allergic patients, agree partially with the current literature. Nonetheless, the association between VD levels and allergies appeared weak. Studies involving larger samples would be required to better define the association between VD and allergies.
Garnet is the archetypal cubic mineral, occurring in a wide variety of rock types in Earth's crust and upper mantle. Owing to its prevalence, durability and compositional diversity, garnet is used to ...investigate a broad range of geological processes. Although birefringence is a characteristic feature of rare Ca–Fe3+ garnet and Ca-rich hydrous garnet, the optical anisotropy that has occasionally been documented in common (that is, anhydrous Ca–Fe2+–Mg–Mn) garnet is generally attributed to internal strain of the cubic structure. Here we show that common garnet with a non-cubic (tetragonal) crystal structure is much more widespread than previously thought, occurring in low-temperature, high pressure metamorphosed basalts (blueschists) from subduction zones and in low-grade metamorphosed mudstones (phyllites and schists) from orogenic belts. Indeed, a non-cubic symmetry appears to be typical of common garnet that forms at low temperatures (<450°C), where it has a characteristic Fe–Ca-rich composition with very low Mg contents. We propose that, in most cases garnet does not initially grow cubic. Our discovery indicates that the crystal chemistry and thermodynamic properties of garnet at low-temperature need to be re-assessed, with potential consequences for the application of garnet as an investigative tool in a broad range of geological environments.
The use of bacteriophages represents a valid alternative to conventional antimicrobial treatments, overcoming the widespread bacterial antibiotic resistance phenomenon. In this work, we evaluated ...whether biomimetic hydroxyapatite (HA) nanocrystals are able to enhance some properties of bacteriophages. The final goal of this study was to demonstrate that biomimetic HA nanocrystals can be used for bacteriophage delivery in the context of bacterial infections, and contribute - at the same time - to enhance some of the biological properties of the same bacteriophages such as stability, preservation, antimicrobial activity, and so on.
Phage isolation and characterization were carried out by using Mitomycin C and following double-layer agar technique. The biomimetic HA water suspension was synthesized in order to obtain nanocrystals with plate-like morphology and nanometric dimensions. The interaction of phages with the HA was investigated by dynamic light scattering and Zeta potential analyses. The cytotoxicity and intracellular killing activities of the phage-HA complex were evaluated in human hepatocellular carcinoma HepG2 cells. The bacterial inhibition capacity of the complex was assessed on chicken minced meat samples infected with
Rissen.
Our data highlighted that the biomimetic HA nanocrystal-bacteriophage complex was more stable and more effective than phages alone in all tested experimental conditions.
Our results evidenced the important contribution of biomimetic HA nanocrystals: they act as an excellent carrier for bacteriophage delivery and enhance its biological characteristics. This study confirmed the significant role of the mineral HA when it is complexed with biological entities like bacteriophages, as it has been shown for molecules such as lactoferrin.
In this paper, we present the results of a multi-analytical characterization of a glaucophane sample collected in the Piedmont region of northwestern Italy. Investigation methods included optical ...microscopy, powder X-ray diffraction, Fourier-transform infrared spectroscopy, μ-Raman spectroscopy, Mössbauer spectroscopy, electron probe microanalysis, environmental scanning electron microscopy and energy-dispersive X-ray spectroscopy, and scanning/transmission electron microscopy combined with energy-dispersive X-ray spectroscopy and electron energy-loss spectroscopy. In addition to the crystal-chemical characterization of the sample from the mesoscale to the near-atomic scale, we have also conducted an extended study on the morphology and dimensions of the mineral particles. The main finding is that studying the same particle population at different magnifications yields different results for mineral habit, dimensions, and dimensional distributions. As glaucophane may occur as an elongate mineral particle (e.g., asbestiform glaucophane occurrences in California and Nevada), the observed discrepancies therefore need to be considered when assessing potential breathability of such particles, with implications for future regulations on elongate mineral particles. While the sample preparation and particle counting methods are not directly investigated in this work, our findings suggest that different magnifications should be used when characterizing an elongate mineral particle population, irrespective of whether or not it contains asbestiform material. These results further reveal the need for developing improved regulation for elongate mineral particles. We thus propose a simple methodology to merge the datasets collected at different magnifications to provide a more complete description and a better risk evaluation of the studied particle population.
Tremolite is one of the most common amphibole species and, in the fibrous form (i.e., characterized by crystals/particles consisting of fibres with length > 5 µm, width < 3 µm and aspect ratio > 3), ...one of the six asbestos minerals. Until now the attention of crystallographers has focused only on samples from continental environment. Here we report the first chemical and structural data of a tremolite asbestos found along the Mid Atlantic Ridge (MAR) at the eastern intersection of the Romanche Transform Fault (Equatorial MAR). Tremolite is associated with chlorite and lizardite and was formed through the green shale facies lower than zeolite in a predominantly fluid system. MAR tremolite asbestos shows very slight deviations from the ideal crystal structure of tremolite. Differences in cation site partitioning were found with respect to tremolite asbestos from ophiolitic complexes, attributed to the different chemical-physical conditions during the mineral formation. In particular, oceanic tremolite asbestos is enriched in Al and Na, forming a trend clearly distinct from the continental tremolites.
Twinning is an important deformation mode in plastically deformed hexagonal close-packed materials. The extremely high twin growth rates at the nanoscale make atomistic simulations an attractive ...method for investigating the role of individual twin/matrix interfaces such as twin boundaries and basal-prismatic interfaces in twin growth kinetics. Unfortunately, there is no single framework that allows researchers to differentiate such interfaces automatically, neither in experimental in-situ transmission electron microscopy analysis images nor in atomistic simulations. Moreover, the presence of alloying elements introduces substantial noise to local atomic environments, making it nearly impossible to identify which atoms belong to which interface. Here, with the help of advanced machine learning methods, we provide a proof-of-concept way of using the local stress field distribution as an indicator for the presence of interfaces and for determining their types. We apply such an analysis to the growth of twin embryos in Mg-10 at.% Al alloys under constant stress and constant strain conditions, corresponding to two extremes of high and low strain rates, respectively. We discover that the kinetics of such growth is driven by high-energy basal-prismatic interfaces, in line with our experimental observations for pure Mg.
Display omitted
•Applied ML to atomistic simulations of twin embryo growth in Mg alloy.•Identified and tracked twin-matrix interfaces using stress components.•Low strain rate: growth driven by low-energy twin boundaries.•High strain rate: growth driven by high-energy basal-prismatic interfaces.•Results are experimentally validated for later twin growth stages.
We investigated the oxidation behaviour of a synthetic potassic-ferro-richterite up to 750 °C by using simultaneous X-ray absorption spectroscopy and X-ray diffraction experiments with synchrotron ...radiation. From the X-ray diffraction results, we observed an abrupt decrease of cell dimensions at ∼335 °C accompanied by an anomalous increase in the monoclinic cell angle β. From the analysis of the XANES spectra at the iron K-edge, we observed that the structural shrinkage is due to the iron oxidation process, coupled to hydrogen loss, occurring at ∼315 °C, slightly before the cell contraction. Combining these results with previous studies performed on similar samples by single-crystal structure refinement, Mössbauer, high temperature-Fourier transform IR and Raman spectroscopies, we show that the temperature evolution in Fe-amphiboles is a multi-step process. Following the iron oxidation driven by temperature, the structural dynamics in this double-chain silicate is ruled by local strains in the ribbon of iron-filled octahedra, mainly due to the contraction of the M(1) site.
We present a study of olivine-hosted glass/melt inclusions (MIs) in the most primitive rocks erupted at Procida Island, within the Phlegraean Volcanic District (PVD), Southern Italy. MIs were ...analyzed by combined Scanning Electron Microscopy coupled with Energy Dispersive X-ray-detectors, Wavelength Dispersive X-ray-equipped Electron Microprobe and Fourier Transform Infrared (FT-IR) Spectroscopy; notably, the novel Focal-Plane-Array mode provided high-resolution FT-IR images evidencing the distribution of the C–H–O species across samples. Olivines range in composition from Fo₈₅ to Fo₉₀, do not show chemical zoning and are totally anhydrous. The majority of the MIs are glassy, while only few are completely crystallized. Some MIs, however, show the occurrence of crystal nuclei, i.e., nano- to micro-sized pyroxenes and oxides, and appear as low-crystallized MIs. The glass of crystal-free and low-crystallized MIs shows K-affinity and a compositional range along the basalt, trachy-basalt, shoshonite, tephrite basanite and phono-tephrite array. H₂O and CO₂ contents up to 2.69wt.% and 2653ppm, respectively, define a major degassing trend with small isobaric deviations. The collected data allow recalculating entrapment pressures from ~350MPa to <50MPa and suggest that the magma ascent was dominated by degassing. Crystallization was a minor process, likely also consequent to local CO₂-fluxing. Mingling occurred between variable degassed and crystallized magma portions during decompression. The geochemical and isotopic data of Procida glasses and rocks, and the compositional relationship between our MIs and those from slightly more evolved and radiogenic Phlegraean products, indicate that Procida basalts are an adequate parental end-member for the PVD. Our data suggest that a CO₂-rich magma source was stored at depths of at least 13–14km (i.e., 350MPa) beneath the PVD. Fast ascent of magma batches directly started from this depth shortly before PVD trachy-basaltic to shoshonitic eruptions. Such results have implication on volcanic hazard assessment in the PVD area.
The MAX phases are a group of ternary carbides and nitrides with potential for use in advanced high temperature applications. Numerous studies have shown their main deformation mechanism to be basal ...plane slip, even in extreme orientations, yet the fundamentals of this mechanism and dependencies on size and applied stress state remain inconclusive. Based on similar studies in Ti3SiC2, Ti3AlC2 and Ti2AlC, the current work investigated the onset of basal plane slip as a function of loading orientation by compressing single crystal micropillars of Cr2AlC. The results suggest clear changes in the critical resolved shear stress with loading orientation (non-Schmid effects), and attempts were made to rationalize this behavior by comparison with models of dislocation activity. On this basis, it is proposed that external influences on dislocation mobility are likely the governing factor in the observed non-Schmid effects in the MAX phases.
Display omitted
PDF
