Experimental cannibalization of plagioclase by alkaline basalt magmas

Time-series crystallization/dissolution experiments were conducted on a natural potassic basalt seeded with bytownitic plagioclases (Plg) at atmospheric pressure, in air, at 1180- 1240 °C and isothermal dwell time up to 20 hours. Plg-seed presence promotes the early formation of new-Plg, dampening the clinopyroxene (Cpx) crystallization. New-Plgs grow at a rate from 10-6 up to 10-8 cm·s-1 as the dwell time increases. Seeds overgrow at similar rate. Cpx crystallizes with a delay of at least 3 hours; this has a significant impact on the composition of both residual melt and new-Plgs. For undercooling >35 °C the Cpx delay causes a strong supersaturation of this phase in the melt resulting in a decrease in the new-Plg nucleation rate by 2 orders of magnitude in the 3 h-experiment. In the 15h-run, Cpx coarsening and the decrease of crystallinity suggest the achievement of a near-equilibrium conditions. Cpx growth rate is in the order of 10-7 cm·s-1 showing very limited variation. Finally, for the investigated superheating (5-15 °C) only the long lasting experiments allows an estimation of Plg dissolution rate (10-9 cm·s-1) although changes in the melt composition are already detectable in the 3h-runs. As a whole our results suggest that in natural systems, the takeover of antecrysts/ xenocrysts by a magma can induce on a short time scales, changes in its initial nucleation behavior with remarkable petrological implications for the solidification paths and eruptive dynamics of potassic magmatic systems

Experimental partitioning of halogens and other trace elements between olivine, pyroxenes, amphibole and aqueous fluid at 2 GPa and 900–1,300 °C

We present new partition coefficients for various trace elements including Cl between olivine, pyroxenes, amphibole and coexisting chlorine-bearing aqueous fluid in a series of high-pressure experiments at 2 GPa between 900 and 1,300 °C in natural and synthetic systems. Diamond aggregates were added to the experimental capsule set-up in order to separate the fluid from the solid residue and enable in situ analysis of the quenched solute by LA–ICP–MS. The chlorine and fluorine contents in mantle minerals were measured by electron microprobe, and the nature of OH defects was investigated by infrared spectroscopy. Furthermore, a fluorine-rich olivine from one selected sample was investigated by TEM. Results reveal average Cl concentrations in olivine and pyroxenes around 20 ppm and up to 900 ppm F in olivine, making olivine an important repository of halogens in the mantle. Chlorine is always incompatible with Cl partition coefficients D Cl olivine/fluid varying between 10−5 and 10−3, whereas D Cl orthopyroxene/fluid and D Cl clinopyroxene/fluid are ~10−4 and D Cl amphibole/fluid is ~5 × 10−3. Furthermore, partitioning results for incompatible trace element show that compatibilities of trace elements are generally ordered as D amph/fluid ≈ D cpx/fluid > D opx/fluid > D ol/fluid but that D mineral/fluid for Li and P is very similar for all observed silicate phases. Infrared spectra of olivine synthesized in a F-free Ti-bearing system show absorption bands at 3,525 and ~3,570 cm−1. In F ± TiO2-bearing systems, additional absorption bands appear at ~3,535, ~3,595, 3,640 and 3,670 cm−1. Absorption bands at ~3,530 and ~3,570 cm−1, previously assigned to humite-like point defects, profit from low synthesis temperatures and the presence of F. The presence of planar defects could not be proved by TEM investigations, but dislocations in the olivine lattice were observed and are suggested to be an important site for halogen incorporation in olivine

Volatile and major element zonation within melt inclusions: A natural diffusion experiment

The diffusivities of volatile elements in silicate melts significantly impact petrological processes [e.g. 1, 2]. Although many studies of volatile diffusion in silicic melts have been undertaken, there have been few studies in basaltic melts [e.g. 3], and most of these have concentrated on the diffusion of only one or two elements in each experiment

Fatty acids and triacylglycerols profiles from sicilian (Cold pressed vs. soxhlet) grape seed oils

Among the Sicilian economic productive sectors, that of wine production has today a considerable economic value. However, with the growth of this sector, notable was the increase in the production of waste, which to date is not only an economic damage for companies, but also a threat to the environment. It is known that waste from wine production has properties (e.g., antioxidants) which have potential reuse at cosmetic, pharmaceutical and nutritional levels to obtain economically sustainable applications. A new goal is given by the recovery of added value compounds from agri-food wastes and by-products. Grape seed oil is a promising vegetable fat and cold pressing does not involve the use of chemicals, which are harmful to health. It implies that cold-pressed seed oils may contain phytochemicals, as well as natural antioxidants, more than refined oils. In this context, this works aims at studying the chemical characterization (triglycerides profile and composition in fatty acids) of grape seed oils obtained from Soxhlet and cold pressed extraction from Sicilian red grape seeds and white grape seeds. The possibility of obtaining high yields of triglycerides and fatty acids from the waste of wine production through new extraction methods would open up new perspectives for the reuse of waste in a human and animal food context. The results of this work allow the opening up of new perspectives to reuse and then reduce these wastes, helping not only to reduce the damage to the environment and costs for companies but also to create a new product that is environmentally sustainable and with an important economic value

Chemical zonation in olivine-hosted melt inclusions

Significant zonation in major, minor, trace, and volatile elements has been documented in naturally glassy olivine-hosted melt inclusions from the Siqueiros Fracture Zone and the Galapagos Islands. Components with a higher concentration in the host olivine than in the melt (e.g., MgO, FeO, Cr_2O_3, and MnO) are depleted at the edges of the zoned melt inclusions relative to their centers, whereas except for CaO, H_2O, and F, components with a lower concentration in the host olivine than in the melt (e.g., Al_2O_3, SiO_2, Na_2O, K_2O, TiO_2, S, and Cl) are enriched near the melt inclusion edges. This zonation is due to formation of an olivine-depleted boundary layer in the adjacent melt in response to cooling and crystallization of olivine on the walls of the melt inclusions, concurrent with diffusive propagation of the boundary layer toward the inclusion center. Concentration profiles of some components in the melt inclusions exhibit multicomponent diffusion effects such as uphill diffusion (CaO, FeO) or slowing of the diffusion of typically rapidly diffusing components (Na_2O, K_2O) by coupling to slow diffusing components such as SiO_2 and Al_2O_3. Concentrations of H_2O and F decrease toward the edges of some of the Siqueiros melt inclusions, suggesting either that these components have been lost from the inclusions into the host olivine late in their cooling histories and/or that these components are exhibiting multicomponent diffusion effects. A model has been developed of the time-dependent evolution of MgO concentration profiles in melt inclusions due to simultaneous depletion of MgO at the inclusion walls due to olivine growth and diffusion of MgO in the melt inclusions in response to this depletion. Observed concentration profiles were fit to this model to constrain their thermal histories. Cooling rates determined by a single-stage linear cooling model are 150–13,000 °C h^(−1) from the liquidus down to ~1,000 °C, consistent with previously determined cooling rates for basaltic glasses; compositional trends with melt inclusion size observed in the Siqueiros melt inclusions are described well by this simple single-stage linear cooling model. Despite the overall success of the modeling of MgO concentration profiles using a single-stage cooling history, MgO concentration profiles in some melt inclusions are better fit by a two-stage cooling history with a slower-cooling first stage followed by a faster-cooling second stage; the inferred total duration of cooling from the liquidus down to ~1,000 °C ranges from 40 s to just over 1 h. Based on our observations and models, compositions of zoned melt inclusions (even if measured at the centers of the inclusions) will typically have been diffusively fractionated relative to the initially trapped melt; for such inclusions, the initial composition cannot be simply reconstructed based on olivine-addition calculations, so caution should be exercised in application of such reconstructions to correct for post-entrapment crystallization of olivine on inclusion walls. Off-center analyses of a melt inclusion can also give results significantly fractionated relative to simple olivine crystallization. All melt inclusions from the Siqueiros and Galapagos sample suites exhibit zoning profiles, and this feature may be nearly universal in glassy, olivine-hosted inclusions. If so, zoning profiles in melt inclusions could be widely useful to constrain late-stage syneruptive processes and as natural diffusion experiments

A case report of IgG4-related disease: an insidious path to the diagnosis through kidney, heart and brain

BACKGROUND: IgG4-related disease, described around the years 2000 as a form of autoimmune pancreatitis, is now increasingly accepted as a systemic syndrome. The diagnosis is based on both comprehensive and organ-specific criteria. For the kidney, Mayo clinic classification and the guidelines of the Japanese Nephrology Society are used. Ultimately, together with parameters that characterize every organ or apparatus involved, the key element is the confirmation of growing levels of IgG4 in blood or in tissues. CASE PRESENTATION: We describe a male patient with chronic renal failure associated to hypertension without proteinuria. IgG4-related disease was diagnosed through renal biopsy. After an initial positive response to steroids, he presented tinnitus, and histological assessment showed cerebral and subsequently cardiac damage, both IgG4-related. This case appears unique for the type of histologically documented cardiac and neurological parenchymal involvement, and at the same time, exemplifies the subtle and pernicious course of the disease. Frequently, blurred and non-specific signs prevail. Here, kidney damage was associated with minimal urinary findings, slowly progressive renal dysfunction and other factors that can be equivocated in the differential diagnosis. Neurological involvement was represented by tinnitus alone, while cardiac alterations were completely asymptomatic. CONCLUSIONS: This report is representative of the neurological and cardiac changes described in the literature for IgG4-related disease, which may be correlated or not with the renal form and highlights the need, in some cases, of targeted therapeutic approaches. In addition to glucocorticoids, as in this case, rituximab may be necessary

Effect of beta-Dystroglycan Processing on Utrophin / DP116 Anchorage in Normal and MDX Mouse Schwann Cell Membrane

In the peripheral nervous system, utrophin and the short dystrophin isoform (Dp116) are co-localized at the outermost layer of the myelin sheath of nerve fibers; together with the dystroglycan complex. In peripheral nerve, matrix metalloproteinase (MMP) creates a 30 kDa fragment of beta-dystroglycan, leading to a disruption of the link between the extracellular matrix and the cell membrane. Here we asked if the processing of the beta-dystroglycan could influence the anchorage of Dp116 or/and utrophin in normal and mdx Schwann cell membrane. We showed that MMP-9 was more activated in mdx nerve than in wild-type one. This activation leads to an accumulation of the 30 kDa beta-dystroglycan isoform and have an impact on the anchorage of Dp116 and utrophin isoforms in mdx Schwann cells membrane. Our results showed that Dp116 had greater affinity to the full length form of beta-dystroglycan than the 30 kDa form. Moreover, we showed for the first time that the short isoform of utrophin (Up71) was over-expressed in mdx Schwann cells compared to wild-type. In addition, this utrophin isoform (Up71) seems to have greater affinity to the 30 kDa beta-dystroglycan which could explain a more stabilization of this 30 kDa at the membrane compartment. Our results highlight the potential participation of the short utrophin isoform and the cleaved form of beta-dystroglycan in mdx Schwann cell membrane architecture