56 research outputs found
Surface nanostructuring of TiO2 thin films by ion beam irradiation
This work reports a procedure to modify the surface nanostructure of TiO2 anatase thin films through ion beam irradiation with energies in the keV range. Irradiation with N+ ions leads to the formation of a layer with voids at a depth similar to the ion-projected range. By setting the ion-projected range a few tens of nanometers below the surface of the film, well-ordered nanorods appear aligned with the angle of incidence of the ion beam. Slightly different results were obtained by using heavier (S+) and lighter (B+) ions under similar conditions
Interconvertible Hydrochlorothiazide–Caffeine Multicomponent Pharmaceutical Materials: A Solvent Issue
The design of new multicomponent pharmaceutical materials that involve different active
pharmaceutical ingredients (APIs), e.g., drug-drug cocrystals, is a novel and interesting approach
to address new therapeutic challenges. In this work, the hydrochlorothiazide-caffeine (HCT–CAF)
codrug and its methanol solvate have been synthesized by mechanochemical methods and thoroughly
characterized in the solid state by powder and single crystal X-ray diffraction, respectively, as well as
differential scanning calorimetry, thermogravimetric analyses and infrared spectroscopy. In addition,
solubility and stability studies have also been performed looking for improved physicochemical
properties of the codrug. Interestingly, the two reported structures show great similarity, which allows
conversion between them. The desolvated HCT–CAF cocrystal shows great stability at 24 h and an
enhancement of solubility with respect to the reference HCT API. Furthermore, the contribution of
intermolecular forces on the improved physicochemical properties was evaluated by computational
methods showing strong and diverse H-bond and π–π stacking interactions.Spanish Agencia Estatal de Investigacion of the Ministerio de Ciencia, Innovacion y Universidades (MICIU)European Union (EU)
PGC2018-102047-B-I00MICIU/AEI from SPAIN
CTQ2017-85821-
LiNi0.5Mn1.5O4 Thin Films Grown by Magnetron Sputtering under Inert Gas Flow Mixtures as High-Voltage Cathode Materials for Lithium-Ion Batteries
Delivering a commercial high-voltage spinel LiNi0.5Mn1.5O4 (LNMO) cathode electrode for Li-ion batteries would result in a significant step forward in terms of energy density. However, the structural ordering of the spinel and particle size have considerable effects on the cathode material's cyclability and rate capability, which are crucial challenges to address. Here, a novel mid-frequency alternating current dual magnetron sputtering method was presented, using different Ar-N-2 gas mixtures ratios for the process gas to prepare various LNMO thin films with highly controlled morphology and particle size; as determined from X-ray diffraction, Raman spectroscopy and electron microscopy. It resulted in enhanced cycling and rate performance. This processing method delivered N-containing LNMO thin film electrodes with up to 15 % increased discharge capacity at 1 C (120 mAh g(-1)) with respect to standard LNMO (grown under only Ar gas flow) thin film electrodes, along with outstanding rate performance up to 10 C (99 mAh g(-1)) in the operating voltage window 3.5-4.85 V vs. Li+/Li. Besides, electrochemical impedance spectroscopy results showed that the intricate phase transitions present in standard LNMO electrodes were almost suppressed in N-containing LNMO thin films grown under different Ar-N-2 gas flow mixtures
Influence of plasma-generated negative oxygen ion impingement on magnetron sputtered amorphous SiO2 thin films during growth at low temperatures
Growth of amorphous SiO2 thin films deposited by reactive magnetron sputtering at low temperatures
has been studied under different oxygen partial pressure conditions. Film microstructures varied from
coalescent vertical column-like to homogeneous compact microstructures, possessing all similar
refractive indexes. A discussion on the process responsible for the different microstructures is carried
out focusing on the influence of (i) the surface shadowing mechanism, (ii) the positive ion
impingement on the film, and (iii) the negative ion impingement. We conclude that only the trend
followed by the latter and, in particular, the impingement of O- ions with kinetic energies between 20
and 200 eV, agrees with the resulting microstructural changes. Overall, it is also demonstrated that
there are two main microstructuring regimes in the growth of amorphous SiO2 thin films by
magnetron sputtering at low temperatures, controlled by the amount of O2 in the deposition reactor,
which stem from the competition between surface shadowing and ion-induced adatom surface
mobilityMinisterio de Innovación español-MAT 2007-65764Ministerio de Innovación español (CONSOLIDER INGENIO 2010)-CSD2008-00023Junta de Andalucía-TEP2275, TEP5283, P07-FQM-03298 y P10-FQM-690
Influence of canopy fruit location on morphological, histochemical and biochemical changes in two oil olive cultivars
The influence of different irradiance conditions was evaluated under natural solar radiation by comparing well-exposed (in) and shaded fruit (out) in canopies of olive trees (Olea europaea L). Over a 2-year period, from 50 days after full bloom up to harvest time, “in” and “out” olive samples of two genotypes (“Frantoio Millennio” and “Coratina 5/19”) were periodically collected. Morphological, histochemical, and biochemical analysis were performed to study the changes on fruit morphometric traits, oil body accumulation, and b-glucosidase enzyme activity. Some parameters were modified by shading inside the canopy in which the proportion of incident photosynthetically active radiation intercepted by the crop was 47%. Shaded fruits developed at slow rate and were characterized by late darkgoing time, reduced size, with a tendency toward oblong shape. The rapid histochemical procedure proposed to estimate the oil body accumulation during fruit ripening showed that a reduced irradiance caused a decrease in oil body density. The canopy position influenced, in a different way, the b-glucosidase activity in relation to the fruit-ripening stage in both genotypes. These findings indicate that providing an adequate and uniform lighting of the olive canopy by careful choices of orchard management practices can be a key factor for several yield components
Supersonic Kinks in Coulomb lattices
There exist in nature examples of lattices of elements for which the
interaction is repulsive, the elements are kept in place because different reasons, as
border conditions, geometry (e.g., circular) and, certainly, the interaction with other
elements in the system, which provides an external potential. A primer example are
layered silicates as mica muscovite, where the potassium ions form a two dimensional
lattice between silicate layers. We propose an extremely simplified model of this
layer in order to isolate the properties of a repulsive lattice and study them. We
find that they are extremely well suited for the propagation of supersonic kinks
and multikinks. Theoretically, they may have as much energy and travel as fast as
desired. This striking results suggest that the properties of repulsive lattices may be
related with some yet not fully explained direct and indirect observations of lattice
excitations in muscovite
Canopy fruit location can affect olive oil quality in Arbequina hedgerow orchards
The effect of location of fruit in canopies of hedgerow olive trees (Olea europaea L., cv. ‘Arbequina’) on quality of virgin oil was tested by analyzing oils extracted from different height layers and faces of 9 olive hedgerows (6 North-South oriented and 3 East-West). Although sensory attributes were not different other oil quality parameters may be significantly modified by fruit position. In some hedgerows, oils extracted from fruits harvested from higher layers exhibited significantly higher stability against oxidation, along with higher palmitic acid, linoleic acid and phenol contents, but lower oleic acid content. Oils extracted from fruits harvested from East and North facing hedgerows oriented North-South and East-West, respectively, exhibited higher oleic contents and lower saturated and polyunsaturated fatty acid contents. The mean phenol content of oils extracted from fruits from a North-South oriented hedgerow was significantly greater from one of the East-West oriented hedgerows. These findings may be relevant for the design of future olive hedgerows destined for olive oil production
Condiciones y medio ambiente de trabajo en hospitales públicos provinciales de la ciudad de Córdoba, Argentina
Esta investigación se propuso caracterizar las condiciones de empleo, identificar riesgos laborales percibidos el trabajador y estimar la frecuencia de problemas de salud referidos por los integrantes de los equipos de salud de hospitales de la ciudad de Córdoba dependientes del Ministerio de Salud de la provincia de Córdoba.
Se realizó un estudio de corte transversal sobre 453 trabajadores pertenecientes a hospitales públicos provinciales de la ciudad de Córdoba, seleccionados mediante muestreo probabilístico aleatorio simple, con un nivel de confianza del 95% y un error muestral del 5%, en quienes se aplicó un cuestionario autoadministrado durante el segundo semestre de 2012.
Se halló que el 35% del personal está vinculado laboralmente mediante formas de contratación no permanentes. El pluriempleo alcanza al 36% de los encuestados. La percepción de riesgos biológicos alcanza el 77,9%, el 50,7% se expone a sustancias químicas y el 51,7% manipula cargas físicas de gran volumen. Los problemas de salud más frecuentemente señalados fueron: gastritis (28,3%), obesidad (24,3%), lumbalgia (19,6%), alteraciones del sueño (14,1%), tensión arterial elevada (12,4%). Las proporciones de trabajadores no estables y de pluriempleo, y la elevada percepción de riesgos en el ámbito laboral deberían motivar la formulación de políticas y normativas de mejora de las condiciones de trabajo y empleo
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