Biological niches within human calcified aortic valves. Towards understanding of the pathological biomineralization process

Despite recent advances, mineralization site, its microarchitecture, and composition in calcific heart valve remain poorly understood. A multiscale investigation, using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectrometry (EDS), from micrometre up to nanometre, was conducted on human severely calcified aortic and mitral valves, to provide new insights into calcificationp rocess. Our aim was to evaluate the spatial relationship existing between bioapatite crystals, their local growing microenvironment, and the presence of a hierarchical architecture. Here we detected the presence of bioapatite crystals in two different mineralization sites that suggest the action of two different growth processes:a pathological crystallization process that occurs in biological niches and is ascribed to a purely physicochemical process and a matrix- mediated mineralized process in which the extracellular matrix acts as the template for a site-directed nanocrystals nucleation. Different shapes of bioapatite crystallization were observed at micrometer scale in each microenvironment but at the nanoscale level crystals appear to be made up by the same subunit

Micro-imaging VIS-IR spectroscopy of Martian meteorites in support of the future MaMIss spectrometer measurements

In the view of the future ExoMars 2020 mission, an activity of VIS-IR spectral investigations on terrestrial and extraterrestrial Mars Analogues is ongoing, in support of the Ma Miss in situ measurements. Ma_Miss is an imaging spectrometer that works in the range 0.4-2.2 μm with 20nm spectral sampling and that will observe the lateral wall of the borehole generated by ExoMars Rover's drill (Coradini et al., 2001). In this abstract, we describe some results about the spectral properties and characterization of mineral grains of the slabs of two Martian meteorites by means of the SPIM imaging spectrometer. SPIM works in the 0.22-5.05 μm spectral range, with a spatial resolution of 38x38 μm on the sample and represents the spare of the spectrometer on Dawn spacecraft (De Angelis et al., 2015). The meteorites investigated are North West Africa 8657 (NWA8657) and Dar Al Gani 489 (DAG489), basaltic shergottites. The average spectrum of the NWA8657 slab, in comparison with spectral measurements on other martian meteorites (Mcfadden & Cline, 2005) shows low reflectance values and 1 and 2 μm spectral absorptions indicating the strong presence of Ca-pyroxenes. The successive pixel by pixel analyses for the pyroxenes spectral speciation showed a great variability of clinopyroxenes in NWA8657. In fact, the 2 μm absorption at longer wavelength in some pixel does not always correspond to the 1 μm feature at longer wavelength. The average spectrum of DAG 489 is marked by a signature typical of low-Ca pyroxenes. Pixel by pixel analyses of DAG489 shows a more homogeneous composition of the pyroxenes characterized by the two major features centered at 0.98-0.99 and 1.98-2 μm. Further spectral absorptions related to sulfates, phosphates and carbonates were detected that are being validated by SEM-BSD to constrain the formation hystories of these two shergottites

A multi-scale investigation of biological niches within human calcified aortic valves helps to understand the pathological biomineralization process

Calcific aortic valve stenosis (CAVS) is the most common form of heart valve disease in the industrialized countries, being an important public health problem [1]. Ectopic calcifications within aortic valve leaflets are strictly associated with CAVS, interfering with cusps opening, they lead to ventricular outflow obstruction [2]. Up to date no proven medical therapy stops CAVS course progression, so valve replacement is the only possible treatment of severe CAVS. Unfortunately, the degenerative valve calcification process, affects also bioprosthetic implants [3]. Being the molecular mechanisms leading to valve calcification still not understood, our aim was to carry on a multi-scale investigation using Scanning Electron Microscopy, Transmission Electron Microscopy and Energy Dispersive X-ray Spectrometry, to provide new insights into calcification process. Severely calcified aortic (tricuspid type, n = 29; bicuspid type, n = 3) and mitral valves (n = 4) were obtained from patients of both sexes (males=25) and different ages (mean age 72±10, range 41-90 years old) undergoing valve replacement due to severe aortic and mitral valve stenosis. We detected bioapatite crystals in two different mineralization sites: niches and extracellular matrix. This suggests the action of two different growth processes: the first occurs in biological niches and it is ascribed to a purely physico-chemical process; the second has the extracellular matrix acting ass the template for a site-directed nanocrystals nucleation. Different shapes of bioapatite crystallization were observed at micrometer scale in each microenvironment but at the nanoscale level crystals appear made up by the same subunits. We suggest that bioapatite nanocrystals in heart valve may activate a strong inflammatory process leading to irreversible pathological condition that, once activated,may aggravate the inflammatory response against bioapatite nanocrystals leading to a severe calcification process

A geo-chemo-mechanical study of a highly polluted marine system (Taranto, Italy) for the enhancement of the conceptual site model

The paper presents the results of the analysis of the geo-chemo-mechanical data gathered through an innovative multidisciplinary investigation campaign in the Mar Piccolo basin, a heavily polluted marine bay aside the town of Taranto (Southern Italy). The basin is part of an area declared at high environmental risk by the Italian government. The cutting-edge approach to the environmental characterization of the site was promoted by the Special Commissioner for urgent measures of reclamation, environmental improvements and redevelopment of Taranto and involved experts from several research fields, who cooperated to gather a new insight into the origin, distribution, mobility and fate of the contaminants within the basin. The investigation campaign was designed to implement advanced research methodologies and testing strategies. Differently from traditional investigation campaigns, aimed solely at the assessment of the contamination state within sediments lying in the top layers, the new campaign provided an interpretation of the geo-chemo-mechanical properties and state of the sediments forming the deposit at the seafloor. The integrated, multidisciplinary and holistic approach, that considered geotechnical engineering, electrical and electronical engineering, geological, sedimentological, mineralogical, hydraulic engineering, hydrological, chemical, geochemical, biological fields, supported a comprehensive understanding of the influence of the contamination on the hydro-mechanical properties of the sediments, which need to be accounted for in the selection and design of the risk mitigation measures. The findings of the research represent the input ingredients of the conceptual model of the site, premise to model the evolutionary contamination scenarios within the basin, of guidance for the environmental risk management. The study testifies the importance of the cooperative approach among researchers of different fields to fulfil the interpretation of complex polluted eco-systems

Non-Destructive In Situ Study of Plastic Deformations in Diamonds: X-ray Diffraction Topography and µFTIR Mapping of Two Super Deep Diamond Crystals from São Luiz (Juina, Brazil)

Diamonds from Juina, Brazil, are well-known examples of superdeep diamond crystals formed under sublithospheric conditions and evidence would indicate their origins lie as deep as the Earth’s mantle transition zone and the Lower Mantle. Detailed characterization of these minerals and of inclusions trapped within them may thus provide precious minero-petrogenetic information on their growth history in these inaccessible environments. With the aim of studying non-destructively the structural defects in the entire crystalline volume, two diamond samples from this locality, labelled JUc4 and BZ270, respectively, were studied in transmission mode by means of X-ray Diffraction Topography (XRDT) and micro Fourier Transform InfraRed Spectroscopy (µFTIR). The combined use of these methods shows a good fit between the mapping of spatial distribution of extended defects observed on the topographic images and the µFTIR maps corresponding to the concentration of N and H point defects. The results obtained show that both samples are affected by plastic deformation. In particular, BZ270 shows a lower content of nitrogen and higher deformation, and actually consists of different, slightly misoriented grains that contain sub-grains with a rounded-elongated shape. These features are commonly associated with deformation processes by solid-state diffusion creep under high pressure and high temperature

Crystal Chemical Characterisation of Red Beryl by "Standardless" Laser Induced Breakdown Spectroscopy and Single Crystal Refinement by X‐Ray Diffraction: An Example of Validation of an Innovative Method for the Chemical Analyses of Minerals

Laser induced breakdown spectroscopy (LIBS) is a valuable technique for performing qualitative and quantitative chemical analyses of all elements in one shot, including low atomic number elements such as Li and Be. This technique does not require any sample preparation to reveal the atomic species, even when present in trace amounts (< 0.01% m/m ). In this study, for the first time, we provide an accurate mineral formula for a Cs‐rich red beryl by combining crystallographic data obtained using the traditional single‐crystal X‐ray diffraction technique and quantitative chemical analysis data obtained with an innovative "standardless" method: Calibration Free‐LIBS (CF‐LIBS). In particular, a new LIBS prototype coupled with a petrographic microscope (CF‐μLIBS) was used to analyse chemically homogeneous areas of about 10 μm spot size, causing minimal damage to the mineral. The results showed that calibration‐free quantitative analysis is suitable for the quantification of major and minor low and high atomic number elements in beryl. The accuracy of quantification of low atomic number elements by CF‐μLIBS led to the empirical formula: [12](Cs0.006Na0.019K0.017Ca0.019)Σ0.061 [4](Be2.989Li0.011)Σ3.000 [6](Ti0.053Mn0.051Mg0.007Al1.890)Σ2.000 [4](Be0.116Fe0.024Si5.860)Σ6.000 O18. This formula is consistent with the crystal‐structure refinement data and demonstrates the validity of CF‐μLIBS for chemical analyses of minerals containing low atomic number elements

Compositional Variation and Crystal-Chemical Characterization of a Watermelon Variety of Tourmaline from Anjanabonoina, Central Madagascar

A polychrome tourmaline crystal from Anjanabonoina pegmatite (Madagascar) was characterized using a multi-analytical approach. The sample showed a complex concentric zoning and a wide range of colors typical of the variety known as “watermelon”. The sample was cut perpendicularly to the c axis. The basal slice exhibits a rim characterized by narrow, differently colored layers parallel to the prism faces and a relatively homogeneous triangular core. Four main pronounced color zones were identified from the rim to core: a dark green rim (M1RVS); a pale green rim (M1RVC); a pale pink rim (M1CR); and a brownish yellow core (M1CG). Compositional variations in the basal slice were studied by scanning electron microscopy and electron microprobe analyses (WDS mode). The Li content was determined via micro-laser-induced breakdown spectroscopy. To deeply characterize the sample, single crystal structure refinement was also performed on fragments extracted from the four zones. The results show that the polychrome tourmaline sample consists of two different species: the three outer zones are Mn-rich fluor-liddicoatite, whereas the inner zone is Mn-rich fluor-elbaite. The structural and compositional characterization of the color zoning shows that each step of the tourmaline growth is related to a change in the geological environment

Fluor-tsilaisite, NaMn3Al6(Si6O18)(BO3)3(OH)3F, a new tourmaline from San Piero in Campo (Elba, Italy) and new data on tsilaisitic tourmaline from the holotype specimen locality

Fluor-tsilaisite, NaMn3Al6(Si6O18)(BO3)3(OH)3F, is a new mineral of the tourmaline supergroup. It occurs in an aplitic dyke of a LCT-type pegmatite body from Grotta d’Oggi, San Piero in Campo, Elba Island, Italy, in association with quartz, K-feldspar, plagioclase, elbaite, schorl, fluor-elbaite and tsilaisite. Crystals are greenish yellow with a vitreous lustre, sub-conchoidal fracture and white streak. Fluor-tsilaisite has a Mohs hardness of ~7 and a calculated density of 3.134 g/cm3 . In plane-polarized light, fluor-tsilaisite is pleochroic (O = pale greenish yellow and E = very pale greenish yellow), uniaxial negative. Fluor-tsilaisite is rhombohedral, space group R3m, a = 15.9398(6), c = 7.1363(3) A˚ , V = 1570.25(11) A˚ 3 , Z = 3. The crystal structure of fluor-tsilaisite was refined to R1 = 3.36% using 3496 unique reflections collected with MoKa X-ray intensity data. Crystal-chemical analysis resulted in the empirical formula: X(Na0.69&0.29Ca0.02)S1.00Y(Mn2+ 1.29Al1.21Li0.56Ti0.03)S6.00ZAl6 T (Si5.98Al0.03)S6.00B2.92O27V(OH)3 W[F0.39(OH)0.25O0.36]S1.00. Comparisons were performed between fluor-tsilaisite and a tsilaisitic tourmaline from the same locality as the holotype specimen. This latter tourmaline sample was selected for this study due to its remarkable composition (MnO = 11.63 wt.%), the largest Mn content found in tourmaline so far. Fluor-tsilaisite is related to tsilaisite through the substitution WF $W(OH) and with fluor-elbaite through the substitution Y(Al + Li)$ 2YMn2+, and appears to be a stepwise intermediate during tourmaline evolution from tsilaisite to fluor-elbaite

Fluor-tsilaisite, NaMn3Al6(Si6O18)(BO3)(3)(OH)(3)F, a new tourmaline from San Piero in Campo (Elba, Italy) and new data on tsilaisitic tourmaline from the holotype specimen locality

Fluor-tsilaisite, NaMn3Al6(Si6O18)(BO3)3(OH)3F, is a new mineral of the tourmaline supergroup. It occurs in an aplitic dyke of a LCT-type pegmatite body from Grotta d'Oggi, San Piero in Campo, Elba Island, Italy, in association with quartz, K-feldspar, plagioclase, elbaite, schorl, fluor-elbaite and tsilaisite. Crystals are greenish yellow with a vitreous lustre, sub-conchoidal fracture and white streak. Fluor-tsilaisite has a Mohs hardness of ∼7 and a calculated density of 3.134 g/cm3. In plane-polarized light, fluor-tsilaisite is pleochroic (O = pale greenish yellow and E = very pale greenish yellow), uniaxial negative. Fluor-tsilaisite is rhombohedral, space group R3m, a = 15.9398(6), c = 7.1363(3) Å, V = 1570.25(11) Å3, Z = 3. The crystal structure of fluor-tsilaisite was refined to R1 = 3.36% using 3496 unique reflections collected with MoKα X-ray intensity data. Crystal-chemical analysis resulted in the empirical formula: X(Na0.69□0.29Ca0.02)Σ1.00 Y(Mn2+ 1.29Al1.21Li0.56Ti0.03)Σ6.00 ZAl6 T(Si5.98Al0.03)Σ6.00B2.92O27 V(OH)3 W[F0.39(OH)0.25O0.36]Σ1.00. Comparisons were performed between fluor-tsilaisite and a tsilaisitic tourmaline from the same locality as the holotype specimen. This latter tourmaline sample was selected for this study due to its remarkable composition (MnO = 11.63 wt.%), the largest Mn content found in tourmaline so far. Fluor-tsilaisite is related to tsilaisite through the substitution WF 虠 W(OH) and with fluor-elbaite through the substitution Y(Al + Li) 虠 2YMn2+, and appears to be a stepwise intermediate during tourmaline evolution from tsilaisite to fluor-elbait