191 research outputs found
Generation of a porous scaffold with a starting composition in the CaO-SiO2-MgO-P2O5 system in a simulated physiological environment
Magnesium-based ceramics are involved in orthopedic applications such as bone scaffolds or implant coatings. They provide structural support to cells for bone ingrowth, but highly porous matrices cannot resist severe mechanical stress during implantation. In this study, the laser floating zone (LFZ) technique is used to prepare a dense crystalline material with composition in the CaO-SiO2-MgO-P2O5 system. This material, under physiological conditions, is able to generate a porous scaffold controlled by the dissolution of the MgO phase, meeting the mechanical advantages of a dense material and the biological features of a porous scaffold. FESEM (Field emission scanning electron microscopy), XRD (X-ray Diffraction), EDS (Energy Dispersive X-rays spectroscopy), and ICP ((Inductively Coupled Plasma) analysis were carried out in order to characterize the samples before and after immersion in simulated body fluid (SBF)
Influence of Maturity and Vineyard Location on Free and Bound Aroma Compounds of Grapes from the País Cultivar
Some of the volatile compounds present in grapes give wine is its unique and genuine characteristics. “Terroir” and berry maturity are considered to be the main influences on the expression of these characteristics. This work was undertaken to establish the specific characteristics that define Vitis vinifera cv. País, based on its aromatic profile and free and bound compounds (glycosides), and to assess the effects of location and maturity. Free and bound volatile compounds presented significant differences in the three locations studied. The total amount of free alcohols, acids and ketones depended on the location. During ripening, the amount of aroma precursors increased in all chemical groups in every location studied, and they were found mainly in the skins. With reference to free volatile compounds, it was found that cis-2-hexenol could be a good candidate to assess maturity, and that terpene content seemed to be strongly related to the vineyard location and cultivar conditions. Also, data analysis showed that the free aroma profile seemed to be influenced more by the maturity of the grapes and the bound aroma fraction more by the location
Chemical and Physical Implications of the Use of Alternative Vessels to Oak Barrels during the Production of White Wines
Recently, the use of alternative vessels to oak barrels during winemaking has become increasingly popular, but little is known about their impact on the chemical composition of the resulting wines. To address this issue, a Sauvignon Blanc wine was elaborated from the same grape juice by using cylindrical stainless-steel tanks, oval-shaped concrete vessels, oval-shaped polyethylene vessels, and clay jars in triplicate. Each vessel was used for alcoholic fermentation and the aging of wines over its own lees. Wines elaborated in concrete vessels showed the highest pH and the lowest titratable acidity, most likely related to the observed release of inorganic compounds from the concrete walls. Little effect of the vessels was seen on the wine color and phenolic composition. Wines elaborated in clay jars showed the highest turbidity and the highest content of soluble polysaccharides, while those made using cylindrical stainless-steel tanks showed the highest content of volatile compounds. Despite the observed differences, all of the vessels tested seem suitable for white wine production since every wine showed chemical features that corresponded with the quality standards of Sauvignon Blanc wines.España Universidad de Sevilla, VI Plan Propio de Investigación y Transferencia (Contract number USE-18644-Z
Paleomagnetism from Deception Island (South Shetlands archipelago, Antarctica), new insights into the interpretation of the volcanic evolution using a geomagnetic model
Deception Island shows the most recent exposed active volcanism in the northern boundary of the Bransfield Trough. The succession of the volcanic sequence in the island is broadly divided into pre- and post-caldera collapse units although a well-constrained chronological identification of the well-defined successive volcanic episodes is still needed. A new paleomagnetic investigation was carried out on 157 samples grouped in 20 sites from the volcanic deposits of Deception Island (South Shetlands archipelago, Antarctic Peninsula region) distributed in: (1) volcanic breccia (3 sites) and lavas (2 sites) prior to the caldera collapse; (2) lavas emplaced after the caldera collapse (10 sites); and (3) dikes cutting pre- and the lower- most post-caldera collapse units (5 sites). The information revealed by paleomagnetism provides new data about the evolution of the multi-episodic volcanic edifice of this Quaternary volcano, suggesting that the present-day position of the volcanic materials is close to their original emplace- ment position. The new data have been combined with previous paleomagnetic results in order to tentatively propose an age when comparing the paleomagnetic data with a global geomagnetic model. Despite the uncertainties in the use of averaged paleomagnetic data per volcanic units, the new data in combination with tephra occurrences noted elsewhere in the region suggest that the pre-caldera units (F1 and F2) erupted before 12,000 year BC, the caldera collapse took place at about 8300 year BC, and post-cal- dera units S1 and S2 are younger than 2000 year BC
Tethyan versus Iberian extension during the Cretaceous period in the Eastern Iberian Peninsula: insights from magnetic fabrics
This work investigates how anisotropy of magnetic susceptibility (AMS) recorded the strain related to the Early Cretaceous extensional processes in synrift sediments of the Maestrat basin (eastern Spain). Forty-two sites, distributed throughout the Lower Cretaceous sequence with dominant gentle dips, were sampled. Minerals contributing to the AMS are mainly phyllosilicates. The parallelism between magnetic and sedimentary foliation seems to indicate that a primary (synsedimentary and early diagenetic) magnetic fabric was preserved at 84% of sites. Consequently, preferred orientations of magnetic lineations are interpreted to record the effect of extensional processes coeval with sedimentation and diagenesis during this period. At these 35 sites, two main magnetic lineation orientations are found, delimiting two large domains: a NE–SW orientation prevailing in the NW sector of the basin (parallel to the extension direction of the Iberian basin), and NW–SE to NNW–SSE orientations to the SE (parallel to the extension direction controlling the western Tethys margin). Directional variability demonstrates that the Maestrat basin is located at the boundary between two domains (Iberian and Tethyan) undergoing different plate-scale extensional processes. The subsequent Cenozoic tectonic inversion affected the synsedimentary magnetic fabrics at only a few sites at the borders of the basin, where compressive features are more developed
La Cueva de Castañar y su centro de interpretación
Comunicación presentada en Cuevatur 2016: VI Congreso Español sobre Cuevas Turísticas, Nerja (Málaga), 2016.[ES] La Cueva de Castañar constituye una cavidad única tanto por la variedad de minerales y formas de sus espeleotemas,
como por el tono rojizo de sus paredes. Estas dos características responden a las características de los materiales sobre
los que se desarrolla la cueva. Son materiales correspondientes al Ediácarico (635-541 M.a.), que incluyen una amplia
variedad de rocas (dolomías, magnesitas, pizarras y areniscas). Estos materiales, muy ricos en magnesio y sílice, son
los que se disuelven y alteran para dar lugar a la formación de la cavidad y de sus espeleotemas. La alteración de las
pizarras y areniscas, la disolución de las dolomías y magnesitas y la infiltración de arcillas desde el suelo dan lugar a la
formación de un fino tapiz de color rojo intenso que se deposita sobre las paredes de la cueva, sobre el que muchas
veces nuclean los espeleotemas. La disolución de las dolomías y magnesitas aporta mucho magnesio a las aguas que
circulan por la cueva, lo cual favorece la formación no sólo de calcita (que es lo habitual), sino también de aragonito.
Pero además la composición de las aguas no se ha mantenido constante, lo que ha favorecido que se produjeran
muchas transformaciones entre los minerales ya formados. En definitiva, el amplio espectro mineralógico y las variadas
transformaciones mineralógicas que se observan en la cueva, hacen de esta un laboratorio natural y por tanto una
cavidad única, que se debe conocer, para así poderla conservar en las mejores condiciones posibles. Estas condiciones
son las que hacen que el número de visitantes sea muy limitado, por ello el Centro de Interpretación inaugurado en
2010, cumple sobradamente la labor de dar a conocer los valores únicos de la Cueva de Castañar.[EN] Castañar Cave is a unique cavity due to the variety and morphology of the speleothems it contains, as well as to the
red colour of their walls. These characteristics are due to the hostrocks in which it developed, Ediacaric (635-541 M.a)
dolostones, magnesites and siliciclastic rocks. These materials very rich in Mg and silica, weather and dissolve to give
place to the formation of the cavity and their speleothems. The weathering of the siliciclastic rocks, the dissolution of
dolostones and magnesites and the infiltration of the clays from the overlying soil, allows the formation of a thin red
(clays and Fe-oxides) layer that coats the cavity, and constitute the nucleation site for many speleothems. The dissolution of dolostones and magnesites supplies Mg to the cave waters enabling the formation not only of calcite, but also
aragonite and dolomite (which are rarer in caves). In addition water cave composition has changed over time, allowing
many transformations between the previously formed minerals. When relatively more dilute waters prevail aragonite
transforms into calcite or even both can dissolve, forming the large pores visible in some speleothems. On the contrary
Mg-rich minerals (huntite, dolomite and Mg-rich clays) form in more concentrated waters. In short, the wide mineralogical
spectra and their transformations make this cave a unique cavity and a natural lab, whose detailed study will
help to preserve it under the best possible conditions. This is why the number of visitors is very limited; however the
renewed Centro de Interpretación shows in great detail the characteristics of the Castañar Cave.Este trabajo se incluye en los proyectos: “Estudio ambiental y geológico del Monumento Natural
Cueva de Castañar”, financiado por fondos FEADER (contrato Gobierno de Extremadura
y CSIC) y CGL2014-54818P del MINECO.Peer reviewe
Influence of Maturity and Vineyard Location on Free and Bound Aroma Compounds of Grapes from the Pais Cultivar
Some of the volatile compounds present in grapes give wine is its unique and genuine characteristics.
“Terroir” and berry maturity are considered to be the main influences on the expression of these
characteristics. This work was undertaken to establish the specific characteristics that define Vitis vinifera
cv. País, based on its aromatic profile and free and bound compounds (glycosides), and to assess the effects
of location and maturity. Free and bound volatile compounds presented significant differences in the three
locations studied. The total amount of free alcohols, acids and ketones depended on the location. During
ripening, the amount of aroma precursors increased in all chemical groups in every location studied, and
they were found mainly in the skins. With reference to free volatile compounds, it was found that cis-2-
hexenol could be a good candidate to assess maturity, and that terpene content seemed to be strongly
related to the vineyard location and cultivar conditions. Also, data analysis showed that the free aroma
profile seemed to be influenced more by the maturity of the grapes and the bound aroma fraction more by
the location
Different application dosages of a specific inactivated dry yeast (SIDY) : effect on the polysaccharides, phenolic and volatile contents and color of Sauvignon blanc wines
Aim: The aims of this study were to (i) study the effect of different application dosages of a commercial specific inactivated
dry yeast (SIDY) on several compounds (polysaccharides, phenolic and volatile compounds) and attributes (color parameters)
related to the quality of white wines, and (ii) acquire better knowledge about the use of different dosages of SIDY in white
wines with the objective to improve their quality.
Methods and results: Three different dosages were applied (10, 20 and 40 g hL-1). Treated wines were followed after a
contact time period of two months and after a bottle aging period of three months. Total phenolic content, color intensity,
CIELab coordinates, polysaccharides, low molecular weight phenolic compounds and volatile compounds were evaluated.
Conclusions: Higher dosages of this SIDY resulted in a greater release of polysaccharides into the wine. In parallel, a positive
effect on the reduction or prevention of wine oxidation was observed due to the interaction with certain phenolic compounds.
The application of the highest dosage seems to lead to an adsorption or retention effect of the major identified volatile
compounds. This effect seems to be more evident after the contact time period than after the bottle storage period.
Significance and impact of the study: This study can contribute to improve our knowledge on how applying different
dosages of SIDY affects the physical and chemical quality of white wines.CONICYT-PAI, República de Chile (concurso nacional inserción en el sector productivo, convocatoria 2014) No. 781403003FONDECYT (República de Chile) 11140275FONDECYT (República de Chile) 1140882FONDEQUIP (República de Chile) EQM- 13012
Growth cartilage expression of growth hormone/insulin-like growth factor I axis in spontaneous and growth hormone induced catch-up growth
Introduction: Catch-up growth following the cessation of a growth inhibiting cause occurs in humans and animals. Although its underlying regulatory mechanisms are not well understood, current hypothesis confer an increasing importance to local factors intrinsic to the long bones' growth plate (GP). Aim: The present study was designed to analyze the growth-hormone (GH)-insulin-like growth factor I (IGF-I) axis in the epiphyseal cartilage of young rats exhibiting catch-up growth as well as to evaluate the effect of GH treatment on this process. Material and methods: Female Sprague-Dawley rats were randomly grouped: controls (group C), 50% diet restriction for 3 days + refeeding (group CR); 50% diet restriction for 3 days + refeeding & GH treatment (group CRGH). Analysis of GH receptor (GHR), IGF-I, IGF-I receptor (IGF-IR) and IGF binding protein 5 (IGFBP5) expressions by real-time PCR was performed in tibial growth plates extracted at the time of catch-up growth, identified by osseous front advance greater than that of C animals. Results: In the absence of GH treatment, catch-up growth was associated with increased IGF-I and IGFBP5 mRNA levels, without changes in GHR or IGF-IR. GH treatment maintained the overexpression of IGF-I mRNA and induced an important increase in IGF-IR expression. Conclusions: Catch-up growth that happens after diet restriction might be related with a dual stimulating local effect of IGF-I in growth plate resulting from overexpression and increased bioavailability of IGF-I. GH treatment further enhanced expression of IGF-IR which likely resulted in a potentiation of local IGF-I actions. These findings point out to an important role of growth cartilage GH/IGF-I axis regulation in a rat model of catch-up growth
Vulcanismo cuaternario de la Isla Decepción (Antártida): Una signatura relacionada con la subducción de la Fosa de las Shetland del Sur en el dominio de tras-arco de la Cuenca de Bransfield
Deception Island shows a volcanism related to the Phoenix Plate subduction and roll-back under South Shet- land Block in the present times. The development of the island is related to the evolution and collapse of a volcanic caldera, and this study is focused on the petrology, mineralogy and geochemistry of the post-caldera rocks. We have made a study of the lava flows, dikes and the youngest historic eruption in 1970. These rocks range from dacite to rhyolite and have a microporphyritic texture with olivine and minor clinopyroxene. A pre-caldera basaltic andesite has also been studied. It has a microporphyritic texture with clinopyroxene.The intermediate and acid compositions alternating in the volcanostratigraphic sequence suggest either mafic recharge events or melt extraction from different levels in the deep magmatic system. All the studied compo- sitions share a subduction-related signature similar to other magmatics from the Bransfield Basin. However, compositional differences between pre-caldera and post-caldera rocks indicate a different magma source and depth of crystallisation. According to the geothermobarometric calculations the pre-caldera magmas started to crystallise at deeper levels (13.5–15 km) than the post-caldera magmas (6.2–7.8 km). Specifically, the post- caldera magmas indicate a smaller influence of the subducting slab in the southwestern part of the Bransfield Basin in respect to the available data from other sectors as well as the involvement of crustal contamination in the genesis of the magmas
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