Combination of Acoustic Methods and the Indentation Technique for the Measurement of Film Properties

New techniques are continuously being developed to produce films and thin films, whose properties typically depend on the preparation process, and can be significantly different from those of the material in bulk form. The characterization of thin layers remains an open issue. A precise knowledge of the mechanical properties is crucial in several cases, and is of general interest. A full mechanical characterization includes the determination of both the elastic properties, which characterize the reversible deformations, and the properties which characterize the reversible behaviour. In most cases the elastic behaviour can be completely characterized by the elastic moduli, or equivalently by the components of the elastic tensor. It is well known that also in the simplest case, the homogeneous isotropic continuum, the elastic stiffness cannot be characterized by a single parameter, but needs two independent parameters; in the case of anisotropic solids the number of independent parameters further increases. The inelastic behaviour is typically more complex. Among the methods to perform the mechanical characterization, a specific class exploits vibrations of acoustic nature as a probe of the material behaviour. These methods are non destructive, and involve only elastic strains; therefore, they are intrinsically unable to give indications about any inelastic behaviour. On the other hand, due to the complete absence of inelastic strains, the relationship between the raw measurement results and the stiffness parameters can be more straightforward, and less subjected to uncertainties or to spurious effects, possibly allowing better accuracies. The mechanical characterization of supported films typically requires specific methods. The most widespread technique is indentation, for which a specific standard exists, and which induces both elastic and inelastic strains: It supplies significant information about irreversible deformation, but the extraction of the information concerning the elastic behaviour is non trivial, and typically leads to a single parameter, usually referred to as 'indentation modulus'. If a reasonable assumption about the value of Poisson???s ratio is available, a value of Young modulus can be derived, which obviously depends on the reliability of the adopted assumption. In the case of films, since the nano and micro-structure can be different from that of bulk samples, a well grounded assumption about the value of Poisson???s ratio might be not available. It is also well known that, when supported films are measured, care must be exercised to avoid the influence of the substrate properties. Methods which exploit acoustic vibrations have been developed also for supported films. Acoustic properties depend on stiffness and inertia; therefore, as it happens for bulky samples, acoustic methods require a value of mass density, independently measured. However in acoustic methods the intrinsic absence of inelastic strains makes the derivation of the stiffness parameters less subjected to spurious effects, and less dependent on specific modelling assumptions. Among the techniques based on acoustic excitations, the so called laser ultrasonics techniques rely on impulsive, therefore broadband, excitation, while quantitative acoustic microscopy relies on monochromatic excitation. In the detection of vibrational excitations, substantial advantages are offered by light, a contact-less and inertia-less probe; such advantages are particularly relevant in the measurement of films and small structures. They are exploited by Brillouin spectroscopy, which relies on Brillouin scattering: the inelastic scattering of light by acoustic excitations. Brillouin spectrometry relies on spontaneous thermal excitation, which has a small amplitude, but has the broadest band, allowing access to the GHz and multi GHz band. For all these methods, the outcome is the measurement of the propagation velocity of one or more acoustic modes. If sufficient information is gathered, a full elastic characterization can be achieved by purely vibrational means, if an independent value of the mass density is available. However, a complete elastic characterization by only acoustic means is not always achievable. The results of acoustic methods and of indentation can therefore be combined, with the purpose to obtain a complete elastic characterization, not achievable by each of the techniques alone. This can be particularly useful in the case of new materials or of films of unconventiona structures, for which a reliable assumption about the value of Poisson???s ratio, needed by indentation, is not available. And the combination of techniques anyhow offers a useful cross-check among techniques based on completely different principles. This chapter is devoted to this combination of indentation with acoustic techniques, namely quantitative acoustic microscopy and Brillouin spectroscopy

Injection Length in Staggered Organic Thin Film Transistors: Assessment and Implications for Device Downscaling

In staggered thin film transistors, the injection length is the fraction of the gate to contact overlap that is effectively involved in current injection. Its assessment is important to properly downscale device dimensions. In fact, in order to increase transistor operation speed, the whole device footprint should be downscaled, which means both the gate to contact overlap and the channel length, as they affect the relative weight of gate to contact parasitic capacitances and the carrier transit time along the channel respectively. Nevertheless, it is not advisable to make the gate to contact overlap smaller than the injection length, because this negatively affects contact resistances. Suitable figures of merits are introduced to quantify these aspects, and a method is proposed to extract the injection length from electrical measurements. As an example of application, transistors based on the prototypical n-type polymer poly[N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene) (P(NDI2OD-T2) are analyzed. When the channel length is scaled while driving voltages are kept constant, in P(NDI2OD-T2) the injection length decreases as well, thus proving that the downscaling of the whole device footprint is feasible. The physical origins of this finding are analyzed and traced back to material properties, in order to suggest general guidelines for a successful transistor downscaling

Brain iron deficiency changes the stoichiometry of adenosine receptor subtypes in cortico-striatal terminals. Implications for restless legs syndrome

Brain iron deficiency (BID) constitutes a primary pathophysiological mechanism in restless legs syndrome (RLS). BID in rodents has been widely used as an animal model of RLS, since it recapitulates key neurochemical changes reported in RLS patients and shows an RLS-like behavioral phenotype. Previous studies with the BID-rodent model of RLS demonstrated increased sensitivity of cortical pyramidal cells to release glutamate from their striatal nerve terminals driving striatal circuits, a correlative finding of the cortical motor hyperexcitability of RLS patients. It was also found that BID in rodents leads to changes in the adenosinergic system, a downregulation of the inhibitory adenosine A1 receptors (A1Rs) and upregulation of the excitatory adenosine A2A receptors (A2ARs). It was then hypothesized, but not proven, that the BID-induced increased sensitivity of cortico-striatal glutamatergic terminals could be induced by a change in A1R/A2AR stoichiometry in favor of A2ARs. Here, we used a newly developed FACS-based synaptometric analysis to compare the relative abundance on A1Rs and A2ARs in cortico-striatal and thalamo-striatal glutamatergic terminals (labeled with vesicular glutamate transporters VGLUT1 and VGLUT2, respectively) of control and BID rats. It could be demonstrated that BID (determined by measuring transferrin receptor density in the brain) is associated with a selective decrease in the A1R/A2AR ratio in VGLUT1 positive-striatal terminals

Garnierites and garnierites: Textures, mineralogy and geochemistry of garnierites in the Falcondo Ni-laterite deposit, Dominican Republic

Garnierites (Ni-Mg-bearing phyllosilicates) are significant ore minerals in Ni-laterites of the hydrous silicate-type. In the Falcondo Ni-laterite deposit (Dominican Republic), garnierites are found within the saprolite horizon mainly as fracture-fillings and thin coatings on joints. Field observations indicate an important role of active brittle tectonics during garnierite precipitation. Different greenish colours and textures can be distinguished, which correspond to different mineral phases, defined according to X-ray diffraction (XRD) and electron microprobe (EMP) analyses: a) talc-like (10 Å-type), b) serpentine-like (7 Å-type), c) a mixture of talc- and serpentine-like, and d) sepiolite-like types. Compositional data indicate continuous Mg-Ni solid solution along the joins lizardite-népouite (serpentine-like), kerolite-pimelite (talc-like) and sepiolite-falcondoite (sepiolite-like). In general, talc-like garnierite is dominant in Falcondo Ni-laterite and displays higher Ni contents than serpentine-like garnierites. EMP analyses showing deviations from the stoichiometric Mg-Ni solid solutions of serpentine and talc are best explained by talc- and serpentine-like mixing at the nanoscale. A detailed textural study by means of quantified X-ray element imaging provides a wealth of new information about the relationships between textural position, sequence of crystallization and mineral composition of the studied garnierite samples. These results indicate several stages of growth with variable Ni content, pointing to recurrent changes in the physicalchemical conditions during garnierite precipitation. In addition, our detailed mineralogical study of the Falcondo garnierites revealed that the different types identified have characteristic H2O content and SiO2/MgO ratios, which play important roles during the pyrometallurgy process

Designing a web 2.0 for caregivers of people with chronic health problems

El artículo describe las fases de diseño de la web de apoyo a cuidadoras de personas con problemas crónicos de salud física y mental. Proyecto multicéntrico financiado por el Instituto de Salud Carlos III. En la fase diagnostica se identificaron el perfil de las cuidadoras, sus necesidades e intereses sobre información digital en salud y constituyó el punto de partida para el diseño de la comunidad virtual. Con todos los datos y el análisis de webs afines se diseñó la web: www.cuidadorascronicos.com. Una vez elaborada se puso a prueba para detectar fortalezas y puntos mejorables

El aprendizaje de la parte especial del Derecho Penal a través del sistema de casos

El objeto del proyecto es elaborar materiales de aprendizaje a través de la metodología del estudios de casos penales, desarrollada en el aula, al estilo del sistema anglosajón, con el fin de conseguir una mejor preparación profesional de los alumnos en el ámbito de la parte especial del derecho penal

The prevalence of self-reported underuse of medications due to cost for the elderly: Results from seven European urban communities

Background: The aim of this study was to evaluate the prevalence of self-reported underuse of medications due to procurement costs amongst older persons from seven European urban communities. Methods: The data were collected in a cross-sectional study (“ABUEL, Elder abuse: A multinational prevalence survey”) in 2009. Randomly selected people aged 60–84 years (n = 4,467) from seven urban communities: Stuttgart (Germany), Athens (Greece), Ancona (Italy), Kaunas (Lithuania), Porto (Portugal), Granada (Spain) and Stockholm (Sweden) were interviewed. Response rate - 45.2 %. Ethical permission was received in each country. Results: The results indicate that 3.6 % (n = 162) of the respondents self-reported refraining from buying prescribed medications due to cost. The highest prevalence of this problem was identified in Lithuania (15.7 %, n = 99) and Portugal (4.3 %, n = 28). Other countries reported lower percentages of refraining from buying medications (Germany – 2.0 %, Italy – 1.6 %, Sweden – 1.0 %, Greece – 0.6 %, Spain – 0.3 %). Females refrained more often from buying medications than males (2.6 % vs. 4.4 %, p < 0.0001). The prevalence of this refraining tended to increase with economic hardship. Discussion: These differences between countries can be only partly described by the financing of health-care systems. In spite of the presence of cost reimbursement mechanisms, patients need to make co-payments (or in some cases to pay the full price) for prescribed medications. This indicates that the purchasing power of people in 10.1186/s12913-015-1089-4 the particular country can play a major role and be related with the economic situation in the country. Lithuania, which has reported the highest refrain rates, had the lowest gross domestic product (at the time of conducting this study) of all participating countries in the study. Conclusions: Refraining from buying the prescribed medications due to cost is a problem for women and men in respect to ageing people in Europe. Prevalence varies by country, sex, and economic hardship.The ABUEL was supported by the Executive Agency for Health and Consumers (EAHC) (Grant No., A/2007123) and participating institutions

Com trobar elements rars de la taula periòdica a Catalunya?

Hi ha molts mecanismes de concentració d'elements químics a partir de la seva dispersió geoquímica per tal de formar dipòsits minerals d'interès econòmic. La diversitat de processos geològics que han configurat el subsòl de Catalunya permet esperar una gran diversitat de recursos, molts d'ells explotats ja de fa segles. En aquest treball es discuteixen les possibilitats que alguns recursos d'elements rars, mai investigats en detall, es puguin trobar a Catalunya, i es conclou que hi ha recursos potencials en aquests elements formats per processos de fraccionament magmàtic, hidrotermal i supergènic

Dietary α‐Linolenic Acid, Marine ω‐3 Fatty Acids, and Mortality in a Population With High Fish Consumption: Findings From the PREvención con DIeta MEDiterránea (PREDIMED) Study

Background: Epidemiological evidence suggests a cardioprotective role of α‐linolenic acid (ALA), a plant‐derived ω‐3 fatty acid. It is unclear whether ALA is beneficial in a background of high marine ω‐3 fatty acids (long‐chain n‐3 polyunsaturated fatty acids) intake. In persons at high cardiovascular risk from Spain, a country in which fish consumption is customarily high, we investigated whether meeting the International Society for the Study of Fatty Acids and Lipids recommendation for dietary ALA (0.7% of total energy) at baseline was related to all‐cause and cardiovascular disease mortality. We also examined the effect of meeting the society's recommendation for long‐chain n‐3 polyunsaturated fatty acids (≥500 mg/day). Methods and Results: We longitudinally evaluated 7202 participants in the PREvención con DIeta MEDiterránea (PREDIMED) trial. Multivariable‐adjusted Cox regression models were fitted to estimate hazard ratios. ALA intake correlated to walnut consumption (r=0.94). During a 5.9‐y follow‐up, 431 deaths occurred (104 cardiovascular disease, 55 coronary heart disease, 32 sudden cardiac death, 25 stroke). The hazard ratios for meeting ALA recommendation (n=1615, 22.4%) were 0.72 (95% CI 0.56–0.92) for all‐cause mortality and 0.95 (95% CI 0.58–1.57) for fatal cardiovascular disease. The hazard ratios for meeting the recommendation for long‐chain n‐3 polyunsaturated fatty acids (n=5452, 75.7%) were 0.84 (95% CI 0.67–1.05) for all‐cause mortality, 0.61 (95% CI 0.39–0.96) for fatal cardiovascular disease, 0.54 (95% CI 0.29–0.99) for fatal coronary heart disease, and 0.49 (95% CI 0.22–1.01) for sudden cardiac death. The highest reduction in all‐cause mortality occurred in participants meeting both recommendations (hazard ratio 0.63 [95% CI 0.45–0.87]). Conclusions: In participants without prior cardiovascular disease and high fish consumption, dietary ALA, supplied mainly by walnuts and olive oil, relates inversely to all‐cause mortality, whereas protection from cardiac mortality is limited to fish‐derived long‐chain n‐3 polyunsaturated fatty acids. Clinical Trial Registration URL: http://www.Controlled-trials.com/. Unique identifier: ISRCTN35739639