186,503 research outputs found
Dataset from 'Klever, L., Voudouris, D., Fiehler, K., & Billino, J. (2019). Age effects on sensorimotor predictions: What drives increased tactile suppression during reaching? Journal of Vision, 19(9):9, 1-17. doi:10.1167/19.9.9
No full text<p>Dataset associated with the following publication:</p>
<p>Klever, L., Voudouris, D., Fiehler, K., & Billino, J. (2019). Age effects on sensorimotor predictions: What drives increased tactile suppression during reaching? Journal of Vision.</p>
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<p>We provide two files; one data file contains data on which analyses are based, the other one gives the column labels for the data file.</p>
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<p>For further questions, please contact:<br>
lena.klever[at]psychol.uni-giessen.de</p>
<p> </p>
Microparticles based on water insoluble proteins for delivery of micronutrients in foods
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Ophicalcites from the Upper Tectonic Unit on Tinos, Cyclades, Greece: mineralogical, geochemical and isotope evidence for their origin and evolution
No full textOphicalcites exposed on the island of Tinos, Greece, occur as ellipsoidal bodies within greenschist-facies phyllites of the Upper Cycladic Unit. Close to their outcrops, blocks of serpentinites, metabasic rocks and metasediments were identified, implying a tectonically dismembered ophiolitic sequence in the study area. The ophicalcites comprise brecciated serpentinites cemented by calcite. Based on textural, mineralogical and deformation features, five ophicalcite varieties were discriminated, reflecting calcite precipitation, sedimentary features and increasing brecciation. Serpentinitic fragments comprise antigorite, while Cr-spinel, magnetite, talc and chlorite are accessory minerals. Carbonate veins consist of calcite and minor dolomite, talc, chlorite, and rarely epidote. Bulk rock chemical compositions and Cr-spinel mineral composition point towards a
supra-subduction environment. Carbon and oxygen isotope ratios of calcite imply precipitation from mixed marine and hydrothermal fluids, followed by isotope exchange due to late, greenschist-facies overprint. The Tinos ophicalcites record intraoceanic exhumation of the ultramafics at the seafloor, where faulting and serpentinization caused an extensive network of fractures, healed by carbonates. Such intraoceanic deformation can be attributed either to obduction tectonics expressed by thrusting of oceanic piles, or to transpressional(?) transform faults, or more probably to slip along detachment fault of an oceanic core complex
Understanding gold-(silver)-telluride-(selenide) mineral deposits
No full textGold-(silver)-telluride (selenide) ores occur as epithermal orogenic and intrusion related deposits. Although Te and Se are chalcophile elements and share geochemical affinity with Au, formation of selenides and other elements Ag-Au require acidic or reducing enfironments. The thermodynamic stability conditions for Au and Ag-tellurides and native tellurium indicate an epithermal environment. Analysis of mineral paragenensis, textures and compositional variation in tellurides/selenides suggest petrogenetic processes involving interaction with fluids leading to Au scavenging and entrapment in tellurides, changes in chemistry/rates of fluid infiltration and attaining equilibrium in a given assemblage.Nigel J. Cook, Cristiana L. Ciobanu, Paul G. Spry, Panagiotis Voudouris and the participants of IGCP-48
ALUNITE OCCURRENCES IN GREECE: GEOLOGICAL MINERALOGICAL CONSTRAINTS AND EXPLOITATION
No full textIn this article, occurrences of alunite in northern Greece (Thrace) and the Aegean Islands (Lesvos, Limnos and Milos) are presented and their geological, mineralogical and depositional characteristics are discussed. All alunite-bearing rocks are part of advanced argillic alteration zones in porphyry-epithermal systems hosted in Neogene magmatic rocks. Evidence for early exploitation of alunite in Sapes, Lesvos and Milos, suggest various uses, especially in medicine, in fabric dying, purification of water, or as pigment from classical until recent times
MINERALOGY AND PETROGRAPHY OF THE NW TINOS ISLAND OPHICALCITES, CYCLADES, GREECE.
No full textOphicalcites from Tinos Island, Cyclades, Greece,
better known as ‘green marble of Tinos’, comprise
polygenetic serpentinitic breccias with calcitic
matrix and numerous carbonate veins crosscutting
the formation. They have undergone intense
exploitation for building and decorative purposes
since ancient times. Serpentinitic clasts of the
ophicalcites are composed mainly of antigorite
and they show characteristic mesh textures, while
locally pseudomorphic and non-pseudomorphic
textures are developed. The carbonate phase
consists mostly of calcite, whereas dolomite
replaces calcite locally, especially along zones of
intense tectonic activity. Calcite, mostly as cement
material, presents a strong granoblastic texture
that bonds tightly the serpentinitic clasts. Chlorite
is present in many samples and seems to be a
quite common accessory mineral of the formation
whereas talc, spinel, hematite and magnetite can
also be found. Meter-sized bodies of chromitites
with irregular shapes were also observed in the
studied ophicalcites. They consist of aluminian
chromite, partially replaced by magnetite, Crchlorite,
calcite and base metal sulphides.
Mineralogical, textural and field relationships
data support the idea of a combined tectonichydrothermal
origin of these ophicalcites, while
sedimentary mechanisms have played a minor role
to their formation
Tourmaline from the Fakos porphyry-epithermal Cu-Mo-Au-Te prospect, Limnos island, Greece: Mineral-chemistry and genetic implications
No full textThe Fakos Cu-Mo-Au prospect, in Limnos island, NE Aegean Sea, comprises the first occurrence of porphyry-related tourmaline in Greece (Voudouris & Alfieris, 2005; Fornadel et al., 2012). The prospect is a telescoped porphyry-epithermal system hosted in lower Miocene alkaline to sub-alkaline igneous rocks and middle Eocene to lower Miocene sandstones. Tourmaline occurs within E-trending hydrothermal breccias (Fig. 1a) and quartz-tourmaline veins related to quartz+sericite+tourmaline alteration of the Fakos monzonite (Fig. 1b), as well as disseminations within sericite-altered sandstones. This study presents EPMA data on the Fakos tourmaline and attempts to record any chemical differentiations, which may reflect variations of the ore-forming fluids. Tourmaline occurs as isolated crystals (with size up to 0.5cm) or as radial aggregates. The crystals are optically zoned, usually with a darker core and nearly colorless rim (Fig. 1c). The lighter coloration is caused by a lower concentration of Fe. Due to the minor amount of Ca in all analyzed tourmalines (Fig. 2a; no higher than 0.02 apfu), the optimal plot to distinguish any different species is the binary Fetot/(Fetot + Mg) versus X-site vacancy/(Na + X-site vacancy) (Fig. 2b). This diagram does not distinguish among OH-, F-, and O-bearing species, however, F contents are either below detection, or very low in all analyzed grains, and therefore the W site is dominated by O2- or OH-. Consequently, the magnesio-foitite, dravite, schorl, and foitite fields could be considered as "oxy-magnesiofoitite", oxy-dravite, oxy-foitite, and oxy-schorl fields, respectively. This diagram shows that tourmaline from the sandstones falls into the dravite/oxy-dravite and schorl/oxy-schorl fields, whereas those from the breccia and the quartz veins are restricted to the dravite--oxy-dravite field only. However, the vein-related tourmaline is characterized by higher X-site vacancy/(Na + X-site vacancy) and lower Fetot/(Fetot + Mg) values than those in the other tourmalines studied here. In a plot of X-site vacancy versus Al diagram (Fig. 2c), the compositions of tourmaline from the sandstones and the breccia plot parallel to FeAl-1, and AlO(FeOH)-1 vectors, whereas those from the quartz veins scatter between the two vectors AlO(R(OH))-1 and Al(NaR)-1. In the (charge excess) versus (Fe + Mg + X vacancy) plot (Fig. 2d) it is obvious that the FeAl-1 vector is predominant for the tourmaline in the sandstones. In addition, this diagram shows two compositional groups in excess charge: below -1 and ~ -0.3 to ~0.1. In the second group, most compositions have charge deficiency. Similarly most compositions of tourmaline from the breccia plot parallel to the FeAl-1 vector and have charge deficiency and plot close to the second compositional group of the tourmaline from the sandstones. However, tourmaline compositions from the quartz veins are parallel to the AlO(R(OH))-1 vector and have no charge deficiency. This testifies to negligible Fe3+ content in the tourmaline, although a Mössbauer study is required to test this hypothesis. The Fetot versus Mg diagram (Fig. 2e) and the ternary plot in terms of Fe-Al-Mg (Fig. 2f) show that tourmaline compositions from the sandstones and the breccia parallel the FeAl-1 vector and the oxy-dravite / povondraite (OP) trend, respectively. In contrast to the first- and second-types of tourmaline, the compositions of the quartz vein-related tourmaline parallel the FeMg-1 vector. Thus, they plot over the schorl-dravite join and are not parallel to the OP trend (Fig. 2f). The tourmaline compositions from the quartz veins are characterized by the AlO(R(OH))-1, Al(NaR)-1, and FeMg-1 exchange vectors, probable negligible Fe3+ concentration, and are not parallel to the OP trend. Tourmaline from the Fakos area is Ca-poor that is attributed to Ca deficiency in the host rocks. Tourmaline from altered sandstone and breccia cement have similar major exchange vector substitution FeAl-1 corresponding to isomorphic substitution Fe3+ ↔ Al and parallel to the OP trend. Similarly, tourmaline with the same features have been described from other porphyry deposits (Baksheev et al., 2012; Lynch and Ortega, 1997; Yavuz et al., 1999). Difference in excess charge value between tourmalines from sandstone and breccia cement may be explained by more reducing conditions of tourmaline crystallization in the breccia cement. This more reducing environment may be caused by an increase in the H2S fugacity, which resulted in sulfide deposition. In turn, the latter caused a decrease in the Fe content of the cement tourmaline, because Fe fractionated into sulfide minerals.
Tourmaline from alteration adjacent to quartz-tourmaline veins is different in terms of composition and isomorphic substitutions compared to the previous two types. For these tourmalines, the compositions follow the FeMg-1 vector, which is quite unusual in tourmaline from porphyry systems, but rather represents a major exchange observed in tourmalines from mesothermal gold deposits, greisen, mesothermal tin deposits, and base metal deposits. This is in accordance with field observations at Fakos where quartz-tourmaline veins are transitional from the porphyry to the epithermal environment. Future work will focus on the tourmaline chemistry from Limnos and will be used as a possible vector towards new mineralized (Au-rich) centers in the broader area, as has been suggested for other tourmaline-bearing, porphyry-style alteration assemblages elsewhere
Zein-based colloidal particles for encapsulation and delivery of epigallocatechin gallate
No full textZein, a water insoluble plant protein from a renewable natural source, has been identified as a highly promising material for the production of protein-based colloidal particles for the encapsulation of lipophilic compounds. However, the encapsulation of hydrophilic, water-soluble, bioactive molecules within zein colloidal particles is still unexplored. We show that the encapsulation of epigallocatechin gallate (EGCG) is strongly limited by the weak physical interactions occurring with the zein matrix during the precipitation phase. We demonstrate that the use of sodium caseinate, as a colloidal stabilizer to coat the zein particles, enables the modulation of the encapsulation efficiency and functionality of zein colloidal particles for EGCG delivery. In particular, coated zein particles exhibit a larger size, opposite surface charge and significantly different antioxidant activity, owing to the localization of EGCG affected by the different extent of interaction of EGCG with zein and sodium caseinate. Remarkably, particle formulation also tunes the release rate of EGCG during in vitro digestion and modulates the rate of fat digestion, through the combination of the Pickering emulsion stabilization effect and EGCG interaction with lipase enzyme. Zein-based colloidal particles constitute hence remarkable systems for the tunable and multi-functional delivery of EGCG
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