Effects of thermal and mechanical treatments on montmorillonite homoionized with mono- and polyvalent cations: Insight into the surface and structural changes

Smectite is a family of clay minerals that have important applications. In the majority of these clay minerals, the hydrated interlayer cations play a crucial role on the properties of the clay. Moreover, many studies have revealed that both thermal and grinding treatments affect the MMT structure and that interlayer cations play an important role in the degradation of the structure, primarily after mechanical treatment. In this study, the effects of these treatments on MMTs homoionized with mono (Na+, Li+ or K+) or polyvalent (Ca2+ or Al3+) cations were analyzed by the combination of a set of techniques that can reveal the difference of bulk phenomena from those produced on the surface of the particles. The thermal and mechanical (in an oscillating mill) treatments affected the framework composition and structure of the MMT, and the thermal treatment caused less drastic changes that the mechanical one. The effect of the interlayer cations is primarily due to the oxidation state and, to the size of the cations, which also influenced the disappearance of aluminum in the MMT tetrahedral sheet. These treatments caused a decrease in the surface area and an increase in the particle agglomeration and the isoelectric point. Both treatments caused the leaching of the framework aluminum. Furthermore, the mechanical treatment induced structural defects, such as the breakup of the particles, which favored the dehydroxylation and the increase of the isoelectric points of the montmorillonites.ANPCyT 1360/2006DGICYT FEDER CTQ 2010-1487

Medidas térmicas de alta precisión en el laboratorio geodinámico de Lanzarote

Since 1988, under the exislinq collaboralion belween the Instituto de Astronomía y Geodesia, the Observaloire Royale de Belgique and the European Center for Geodynamics and Seismology,lhermal measuremenls have be en made in the geodynamlc slalion Cueva de los Verdes (Lanzarole, Canary Islands), that have been used lo check the quality oí the sensors used as well the thermal slablllly of the laboralory. Several experiments have been performed:measuremenls oí vertical and horizontal thermal profiles, continuous records of the temperature In different points of rock and continuos record of the ambient temperature of the laboratory. The measures of the temperature profiles have been made in three observation campaings, the results of which we pr:~ent here. We have achieved precisions in the range of 10 oC. We have found a vertical gradient O.03oC/m in the profile temperature. The long and short period variations of rock and ambient temperature have been studied. The results of the harmonic analysis of those temperatures are presented here.Peer reviewe

Organic Molecules in the Galactic Center. Hot Core Chemistry without Hot Cores

We study the origin of large abundances of complex organic molecules in the Galactic center (GC). We carried out a systematic study of the complex organic molecules CH3OH, C2H5OH, (CH3)2O, HCOOCH3, HCOOH, CH3COOH, H2CO, and CS toward 40 GC molecular clouds. Using the LTE approximation, we derived the physical properties of GC molecular clouds and the abundances of the complex molecules.The CH3OH abundance between clouds varies by nearly two orders of magnitude from 2.4x10^{-8} to 1.1x10^{-6}. The abundance of the other complex organic molecules relative to that of CH3OH is basically independent of the CH3OH abundance, with variations of only a factor 4-8. The abundances of complex organic molecules in the GC are compared with those measured in hot cores and hot corinos, in which these complex molecules are also abundant. We find that both the abundance and the abundance ratios of the complex molecules relative to CH3OH in hot cores are similar to those found in the GC clouds. However, hot corinos show different abundance ratios than observed in hot cores and in GC clouds. The rather constant abundance of all the complex molecules relative to CH3OH suggests that all complex molecules are ejected from grain mantles by shocks. Frequent (similar 10^{5}years) shocks with velocities >6km/s are required to explain the high abundances in gas phase of complex organic molecules in the GC molecular clouds. The rather uniform abundance ratios in the GC clouds and in Galactic hot cores indicate a similar average composition of grain mantles in both kinds of regions. The Sickle and the Thermal Radio Arches, affected by UV radiation, show different relative abundances in the complex organic molecules due to the differentially photodissociation of these molecules.Comment: 18 pages, 10 Postscript figures, uses aa.cls, aa.bst, 10pt.rtx, natbib.sty, revsymb.sty revtex4.cls, aps.rtx and aalongtabl.sty. Accepted in A&A 2006. version 2. relocated figures and tables. Language editor suggestions. added reference

Inhalable spray-dried chondroitin sulphate microparticles: effect of different solvents on particle properties and drug activity

Spray-drying stands as one of the most used techniques to produce inhalable microparticles, but several parameters from both the process and the used materials affect the properties of the resulting microparticles. In this work, we describe the production of drug-loaded chondroitin sulphate microparticles by spray-drying, testing the effect of using different solvents during the process. Full characterisation of the polymer and of the aerodynamic properties of the obtained microparticles are provided envisaging an application in inhalable tuberculosis therapy. The spray-dried microparticles successfully associated two first-line antitubercular drugs (isoniazid and rifabutin) with satisfactory production yield (up to 85%) and drug association efficiency (60%-95%). Ethanol and HCl were tested as co-solvents to aid the solubilisation of rifabutin and microparticles produced with the former generally revealed the best features, presenting a better ability to sustainably release rifabutin. Moreover, these presented aerodynamic properties compatible with deep lung deposition, with an aerodynamic diameter around 4 μm and fine particle fraction of approximately 44%. Finally, it was further demonstrated that the antitubercular activity of the drugs remained unchanged after encapsulation independently of the used solvent.UID/Multi/04326/2019; SFRH/BD/52426/2013; ED481B 2018/071info:eu-repo/semantics/publishedVersio

Representaciones sociales del empleo y desempleo de población del País Vasco

Con la base teórico metodológica de las representaciones sociales (RS) se analizan los conceptos de empleo y desempleo en dos grupos poblacionales del País Vasco: jóvenes de 20 y menos años y adultos mayores de 21 años y más. Se utiliza la técnica asociativa de listados libres para conocer el contenido y estructura de las RS, así como la identificación del núcleo central y los elementos periféricos. Para los participantes el empleo es una ocupación que implica acceso al dinero, favorece la satisfacción de necesidades, genera felicidad. Para los mayores de 21 años es un medio para obtener dignidad, realización y futuro. El desempleo implica la falta de dinero, crisis y pobreza, genera desesperanza, depresión y agobio. Para los mayores de 21 años genera problemas, deudas, depresión y angustia, favorece la marginación y culpan a los políticos y al gobierno de su existencia. Se concluye con propuestas de afrontamiento ante el desempleo por parte de participantes.With the theoretical methodological basis of social representations (SR), concepts of employment and unemployment were analyzed in two population groups from the Basque Country: people 20 years old and under and adults over 21 years old. The associative technique of free listings was used in order to know the content and structure of SR, as well as the identification of the central nucleus and the peripheral elements. For the participants employment is an occupation that implies earning money, allows the needs’ satisfaction, and generates happiness. For the group that was 21 years old or older it means, obtaining dignity, to be satisfied and a sure future. Unemployment leads to a lack of money, crisis and poverty, causes hopelessness, depression and overwhelms the person. For the participants over 21 it generates problems, debts, depression, anguish, marginalization and the politicians and the government are blamed for its existence. We conclude with proposals from participants for coping with unemployment

Human-Modified Landscapes Driving the Global Primate Extinction crisis

The world\u27s primates have been severely impacted in diverse and profound ways by anthropogenic pressures. Here, we evaluate the impact of various infrastructures and human-modified landscapes on spatial patterns of primate species richness, at both global and regional scales. We overlaid the International Union for the Conservation of Nature (IUCN) range maps of 520 primate species and applied a global 100 km2 grid. We used structural equation modeling and simultaneous autoregressive models to evaluate direct and indirect effects of six human-altered landscapes variables (i.e., human footprint [HFP], croplands [CROP], road density [ROAD], pasture lands [PAST], protected areas [PAs], and Indigenous Peoples\u27 lands [IPLs]) on global primate species richness, threatened and non-threatened species, as well as on species with decreasing and non-decreasing populations. Two-thirds of all primate species are classified as threatened (i.e., Critically Endangered, Endangered, and Vulnerable), with ~86% experiencing population declines, and ~84% impacted by domestic or international trade. We found that the expansion of PAST, HFP, CROP, and road infrastructure had the most direct negative effects on primate richness. In contrast, forested habitat within IPLs and PAs was positively associated in safeguarding primate species diversity globally, with an even stronger effect at the regional level. Our results show that IPLs and PAs play a critical role in primate species conservation, helping to prevent their extinction; in contrast, HFP growth and expansion has a dramatically negative effect on primate species worldwide. Our findings support predictions that the continued negative impact of anthropogenic pressures on natural habitats may lead to a significant decline in global primate species richness, and likely, species extirpations. We advocate for stronger national and international policy frameworks promoting alternative/sustainable livelihoods and reducing persistent anthropogenic pressures to help mitigate the extinction risk of the world\u27s primate species