128 research outputs found
Twentieth-Century Paleoproteomics: Lessons from Venta Micena Fossils
Proteomics methods can identify amino acid sequences in fossil proteins, thus making it
possible to determine the ascription or proximity of a fossil to other species. Before mass spectrometry
was used to study fossil proteins, earlier studies used antibodies to recognize their sequences.
Lowenstein and colleagues, at the University of San Francisco, pioneered the identification of fossil
proteins with immunological methods. His group, together with Olivares’s group at the University
of Granada, studied the immunological reactions of proteins from the controversial Orce skull
fragment (VM-0), a 1.3-million-year-old fossil found at the Venta Micena site in Orce (Granada
province, southern Spain) and initially assigned to a hominin. However, discrepancies regarding the
morphological features of the internal face of the fossil raised doubts about this ascription. In this
article, we review the immunological analysis of the proteins extracted from VM-0 and other Venta
Micena fossils assigned to hominins and to other mammals, and explain how these methods helped
to determine the species specificity of these fossils and resolve paleontological controversies.Plan Andaluz de Investigacion, Desarrollo e Innovacion, Groups CTS-564
CTS-20
Growth of AlN oriented films on insulating substrates.
This work describes the structural and piezoelectric assessment of aluminum nitride (AlN) thin films deposited by pulsed-DC reactive sputtering on insulating substrates. We investigate the effect of different insulating seed layers on AlN properties (crystallinity, residual stress and piezoelectric activity). The seed layers investigated, silicon nitride (Si3N4), silicon dioxide (SiO2), amorphous tantalum oxide (Ta2O5), and amorphous or nano-crystalline titanium oxide (TiO2) are deposited on glass plates to a thickness lower than 100 nm. Before AlN films deposition, their surface is pre-treated with a soft ionic cleaning, either with argon or nitrogen ions. Only AlN films grown of TiO2 seed layers exhibit a significant piezoelectric activity to be used in acoustic device applications. Pure c-axis oriented films, with FWHM of rocking curve of 6Âş, stress below 500 MPa, and electromechanical coupling factors measured in SAW devices of 1.25% are obtained. The best AlN films are achieved on amorphous TiO2 seed layers deposited at high target power and low sputtering pressure. On the other hand, AlN films deposited on Si3N4, SiO2 and TaOx exhibit a mixed orientation, high stress and very low piezoelectric activity, which invalidate their use in acoustic devices
Influence of Crystal Quality on the Excitation and Propagation of Surface and Bulk Acoustic Waves in Polycrystalline AlN Films
We investigate the excitation and propagation of acoustic waves in polycrystalline aluminum nitride films along the directions parallel and normal to the c-axis. Longitudinal and transverse propagations are assessed through the frequency response of surface acoustic wave and bulk acoustic wave devices fabricated on films of different crystal qualities. The crystalline properties significantly affect the electromechanical coupling factors and acoustic properties of the piezoelectric layers. The presence of misoriented grains produces an overall decrease of the piezoelectric activity, degrading more severely the excitation and propagation of waves traveling transversally to the c-axis. It is suggested that the presence of such crystalline defects in c-axis-oriented films reduces the mechanical coherence between grains and hinders the transverse deformation of the film when the electric field is applied parallel to the surface
Entrenamiento psicolĂłgico en tiro olĂmpico : estudio de un caso
Este artĂculo presenta una intervenciĂłn psicolĂłgica con una tiradora olĂmpica de la modalidad pistola aire comprimido que presenta elevados niveles de estrĂ©s, ansiedad, sĂndrome de burnout y deseos de retirada deportiva. El objetivo fue reducir la sintomatologĂa ansiosa y mejorar su rendimiento deportivo. La intervenciĂłn tuvo una duraciĂłn de doce meses y un seguimiento de seis meses. El entrenamiento psicolĂłgico estuvo compuesto por tĂ©cnicas de planteamiento de objetivos, restructuraciĂłn cognitiva, entrenamiento en parada de pensamiento, autoinstrucciones y tĂ©cnicas de relajaciĂłn y visualizaciĂłn. Tras la intervenciĂłn psicolĂłgica desaparece el sĂndrome de burnout y mejoran los indicadores de estrĂ©s y ansiedad, aumentando el rendimiento deportivo de la tiradora y desapareciendo los pensamientos de abandono deportivo. Con esta investigaciĂłn se pone de manifiesto la importancia del entrenamiento psicolĂłgico en los deportistas.This article sets out a psychological intervention on an Olympic shooter. She competes in the air gun class and shows high levels of stress, anxiety, burnout syndrome and desires to retire from the sport. The main objective was to cut down the symptoms of anxiety and to enhance her sporting performance. The intervention lasted twelve months and was followed up for six months. The psychological training was composed of target-setting techniques, cognitive restructuring, thought stopping training, self instruction and relaxation and visualisation techniques. After the psychological intervention, the burnout syndrome disappeared and stress and anxiety indicators improved which meant that the shooter's sporting performance increased and her desire to retire started to disappear. This research underscores the importance of psychological training in sport.Este artigo apresenta uma intervenção psicolĂłgica com uma atiradora olĂmpica da modalidade de pistola de ar comprimido que apresenta elevados nĂveis de stress, ansiedade, sĂndrome de burnout e desejos de retirada desportiva. O objectivo foi reduzir a sintomatologia ansiosa e potenciar o seu rendimento desportivo. A intervenção teve a duração de doze meses e um perĂodo de monitorização de seis meses. O treino psicolĂłgico foi composto por tĂ©cnicas de formulação de objectivos, restruturação cognitiva, treino em paragem de pensamento, auto-instruções e tĂ©cnicas de relaxamento e visualização. ApĂłs a intervenção psicolĂłgica o sĂndrome de burnout foi eliminado, bem como os pensamentos de abandono desportivo. Por seu turno, verificou-se uma melhoria nos indicadores de stress e ansiedade, tal como no rendimento desportivo da atiradora. Com esta investigação comprova-se a importância do treino psicolĂłgico nos desportistas
Characterization of Amorphous Tantalum Oxide for Insulating Acoustic Mirrors
This work describes the assessment of the acoustic properties of sputtered tantalum oxide films intended as high impedance films for the acoustic isolation of bulk acoustic wave devices operating in the GHz frequency range. The films are grown by sputtering a metallic tantalum target under different oxygen and argon gas mixtures, total pressures, pulsed DC powers and substrate bias. The structural properties of the films are assessed through infrared absorption spectroscopy and X-ray diffraction measurements. Their acoustic impedance is obtained after estimating the mass density by X-ray reflectometry measurements and the longitudinal acoustic velocity by analyzing the longitudinal λ/2 resonance induced in a tantalum oxide film inserted between an acoustic reflector and an AlN-based resonator. A second measurement of the sound velocity is achieved through picosecond acoustic spectroscopy
High-Acoustic-Impedance Tantalum Oxide Layers for Insulating Acoustic Reflectors
This work describes the assessment of the acoustic properties of sputtered tantalum oxide films intended for use as high-impedance films of acoustic reflectors for solidly mounted resonators operating in the gigahertz frequency range. The films are grown by sputtering a metallic tantalum target under different oxygen and argon gas mixtures, total pressures, pulsed dc powers, and substrate biases. The structural properties of the films are assessed through infrared absorption spectroscopy and X-ray diffraction measurements. Their acoustic impedance is assessed by deriving the mass density from X-ray reflectometry measurements and the acoustic velocity from picosecond acoustic spectroscopy and the analysis of the frequency response of the test resonators
On the lateral excitation of shear modes in AlN layered resonators
In this paper we describe the fabrication and frequency characterization of different structures intended for the lateral excitation of shear modes in AlN c-axis-oriented films, which are at the same time designed to minimize the excitation of longitudinal modes. Laterally excited resonators were built on partially metallic (SiO2, W) and insulating (SiOC, Si3N4) acoustic mirrors built on silicon substrates, and on insulating mirrors (SiO2, TaOx) built on insulating glass plates. TiOx seed layers were used to stimulate the growth of highly c-axis oriented AlN films, which was confirmed by XRD and SAW measurements. Coplanar Mo electrodes of different geometries were defined on top of the AlN films to excite the shear modes. All the structures analyzed displayed a clear longitudinal mode, corresponding to an acoustic velocity of 11000 m/s, but a null or extremely weak shear response corresponding to a sound velocity of around 6350 m/s. The simulation of the frequency response based on Mason's model confirms that the shear resonance is extremely weak. The observed longitudinal modes are attributed either to the field applied between the electrodes and a conductive plane (metallic layer or Si substrate) or to the electric field parallel to the c-axis in the edges of the electrodes or in tilted grains. The low excitation of shear modes is attributed to the very low values of electric field strength parallel to the surface
Decidualization modulates the mesenchymal stromal/stem cell and pericyte characteristics of human decidual stromal cells. Effects on antigen expression, chemotactic activity on monocytes and antitumoral activity
Decidual stromal cells (DSCs) are the most abundant cellular component of human decidua and play a central
role in maternal–fetal immune tolerance. Antigen phenotyping and functional studies recently confirmed
the relationship of DSCs with mesenchymal stem/stromal cells (MSCs) and pericytes, the latter two
cell types being closely related or identical. The present study investigated the effect of decidualization, a
process of cell differentiation driven by progesterone (P4) and other pregnancy hormones, on the MSC/pericyte
characteristics of DSCs. To this end we isolated undifferentiated DSC (preDSC) lines that were decidualized
in vitro (dDSC) by the effect of P4 and cAMP. Using flow cytometry, we found significant downmodulation
of the expression of the MSC/pericyte markers α-smooth muscle actin, nestin, CD140b, CD146 and
SUSD2 in dDSCs. The dDSCs did not differ, compared to preDSCs, in the expression of angiogenic factors
(characteristic of pericytes) HGF, FGF2, ANGPT1 or VEGF according to RT-PCR results, but had significantly
increased PGF expression. In migration assays, preDSC-conditioned media had a chemotactic effect on the
THP-1 monocytic line (characteristic of pericytes), and this effect was significantly greater in dDSCconditioned
media. Media conditioned with dDSC, but not with preDSC, induced apoptosis in 4 out of 6 different
tumor cell lines (characteristic of MSCs) according to propidium iodide staining and flow cytometry
results. Our findings show that decidualization induces phenotypic and functional changes in the MSC/pericyte
properties of DSCs that may have a role in the normal development of pregnancy.This article contributes to COST Action CA17116 “International Network for Translating Research on Perinatal Derivatives into Therapeutic Approaches (SPRINT)”, supported by COST (European Cooperation in Science and Technology)
Bacteria detection with high-frequency gravimetric biosensors based on AlN thin film resonators
Gravimetric sensors based on shear-mode resonators are suitable for in-liquid detection of biological species because their quality factors barely decrease during in-liquid operation. However, we have found that in the particular case of large ligands, such as bacteria, the transmission of the surface movement to them appears to be more efficient when movement takes place normal to the surface (longitudinal modes) instead of to parallel to it (shear modes). In this work, we succeeded in detecting bacteria with AlN-based bulk acoustic wave solidly mounted resonators operating in longitudinal modes at 2 GHz that we were unable to detect with shear mode
Advanced determination of piezoelectric properties of AlN thin films on silicon substrates
Piezoelectric deformations of thin, aluminum nitride (AlN) layers, on top of a silicon substrate, were studied by numerical calculations and interferometric measurements. Our calculation by finite element method demonstrates that substrate deformation under the top electrode may be comparable to the electric field induced deformation in the thin AlN layer, for a given applied voltage. Simulations also show the effect of a clamped or free substrate condition and the relative contributions of d33 and d31 piezoelectric constants. A Laser scanning vibrometry technique was used to measure deformations in the top surface with sub-picometer vertical resolution. By comparing calculations and experimental data, quantitative information about both d33 and d31 constants can be obtained
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