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En medio de uno de los acontecimientos que más está afectando al sujeto en su forma de vivir como es el Nihilismo, dejándole en la oscuridad de la alienación, sin referentes de sentido y sin identidad, nos sumergimos en la cuestión de la esperanza. ¿Desde dónde el sujeto puede surgir como esperanza? Nos planteamos el Nihilismo en su condición de negatividad como el lugar de lanzamiento hacia la posibilidad de recrear al sujeto, entrelazando la autonomía con la necesidad constitutiva de arraigado como un cuerpo afectado-subjetivo que se abre hacia nuevos horizontes de sentido en medio del mundo.

When life arose from prebiotic molecules 3.5 billion years ago, what came first? Informational molecules (RNA, DNA), functional ones (proteins), or something else? We argue here for a different logic: rather than seeking a molecule type , we seek a dynamical process. Biology required an ability to evolve before it could choose and optimise materials. We hypothesise that the evolution process was rooted in the peptide folding process. Modelling shows how short random peptides can collapse in water and catalyse the elongation of others, powering both increased folding stability and emergent autocatalysis through a disorder-to-order process. [ABSTRACT FROM AUTHOR]

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An effective method for the synthesis of TiO2–HA composite materials by sol–gel followed by carbon dioxide supercritical drying, is presented. The influence of the amount of hydroxyapatite (HA) in the dioxide of titanium (TiO2) matrix on the crystalline structure and microstructure development of the composites is discussed. Rheological measurements were carried out in order to compare gelation times of precursors with low, medium, and high HA contents. Composites were analyzed by XRD, Raman spectroscopy, FTIR and SEM techniques. The results indicated that the proposed synthesis method leads to TiO2 anatase matrices with dispersed HA nanoparticles up to 30% approximately with gelation times of about 5 min. Highlights: The versatility of the sol–gel method allowed the formation of a TiO2 matrix with dispersed HA nanoparticles (up to 30%), without destabilizing the system. The drying of the TiO2–HA composite gels with supercritical CO2 resulted in porous materials without damage to the macro and microstructure, being the combination of these two techniques higher than conventional methods for obtaining this type of materials. By increasing the HA content in the precursor gels porosity was increased and the TiO2 anatase transition to rutile was delayed. There is no evidence of the formation of secondary phases, the interaction of HA with TiO2 was confirmed by the Raman band at 796 cm−1 in the TiO2–HA composites. [ABSTRACT FROM AUTHOR]

Byline: Ximena. Wortsman, Nelson. Lobos, Rodrigo. De la Parra, Laura. Carreno Active bleeding in plexiform neurofibromatosis can be a life-threatening complication in neurofibromatosis type 1 (NF1). The prompt imaging support [...]

Ocular toxoplasmosis (OT) is commonly diagnosed through the analysis of fundus images of the eye by a specialist. Despite Deep Learning being widely used to process and recognize pathologies in medical images, the diagnosis of ocular toxoplasmosis(OT) has not yet received much attention. A predictive computational model is a valuable time-saving option if used as a support tool for the diagnosis of OT. It could also help diagnose atypical cases, being particularly useful for ophthalmologists who have less experience. In this work, we propose the use of a deep learning model to perform automatic diagnosis of ocular toxoplasmosis from images of the eye fundus. A pretrained residual neural network is fine-tuned on a dataset of samples collected at the medical center of Hospital de Clínicas in Asunción, Paraguay. With sensitivity and specificity rates equal to 94% and 93%,respectively, the results show that the proposed model is highly promising. In order to replicate the results and advance further in this area of research, an open data set of images of the eye fundus labeled by ophthalmologists is made available. [ABSTRACT FROM AUTHOR]

Abstract Background Isolated Left Ventricular Non-compaction (LVNC) is an uncommon disorder characterized by the presence of increased trabeculations and deep intertrabecular recesses. In adults, it has been found that Ejection Fraction (EF) decreases significantly as non-compaction severity increases. In children however, there are a few data describing the relation between anatomical characteristics of LVNC and ventricular function. We aimed to find correlations between morphological features and ventricular performance in children and young adolescents with LVNC using Cardiovascular Magnetic Resonance (CMR). Methods 15 children with LVNC (10 males, mean age 9.7 y.o., range 0.6 - 17 y.o.), underwent a CMR scan. Different morphological measures such as the Compacted Myocardial Mass (CMM), Non-Compaction (NC) to the Compaction (C) distance ratio, Compacted Myocardial Area (CMA) and Non-Compacted Myocardial Area (NCMA), distribution of NC, and the assessment of ventricular wall motion abnormalities were performed to investigate correlations with ventricular performance. EF was considered normal over 53%. Results The distribution of non-compaction in children was similar to published adult data with a predilection for apical, mid-inferior and mid-lateral segments. Five patients had systolic dysfunction with decreased EF. The number of affected segments was the strongest predictor of systolic dysfunction, all five patients had greater than 9 affected segments. Basal segments were less commonly affected but they were affected only in these five severe cases. Conclusion The segmental pattern of involvement of non-compaction in children is similar to that seen in adults. Systolic dysfunction in children is closely related to the number of affected segments.

In the present study, changes in absorptance and emission spectra of MOF-5 after being exposed to water are examined in detail and compared with DFT calculations. The results of the computational studies show the effect of water molecules in the absorptance spectra of MOF-5W, the first hydrolysis product of MOF-5, highlighting the role of the protonation of the ligand on the bandgap of these materials. Finally, the photoluminescence of MOF-5, MOF-5W and MOF-5H (the final hydrolysis product of MOF-5) is analysed in detail. These results indicate that changes in MOF-5 framework caused by the presence of water can be simply tracked by luminescence spectroscopy, making it possible to analyse the degree of hydrolysis (whether the sample contains MOF-5, MOF-5W or MOF-5H) without resorting to XRD analysis, for example. [ABSTRACT FROM AUTHOR]

The effect of the sintering temperature on the formation of secondary phases and ferroelectric properties of Bi0.5(Na0.8K0.2)0.5TiO3 ceramics has been studied. Ceramic powders were prepared by the sol-gel method and sintered at different temperatures. Samples were characterized by X-ray diffraction (XRD), Raman microspectroscopy, scanning electron microscopy, impedance spectroscopy and ferroelectric hysteresis loops. Through XRD and Raman results, the perovskite structure was detected, and the formation of secondary phases was registered. As the sintering temperature was increased, the secondary phase composition was modified. Moreover, dielectric properties were influenced by the resulting grain size and the secondary phase amount. [ABSTRACT FROM AUTHOR]

Tin, titanium and zinc oxide thin films were deposited on glass substrates by spray-pyrolysis. According to the resolution of XRD and SEM, films are single phase and of uniform surfaces. Elastic modulus and film hardness were studied by instrumented indentation. Friction coefficient and wear volume were determined by nanowear procedures. Low friction coefficient and roughness (< 0.2 and ∼ 7 nm, respectively) were measured. Hardness values (between 6 and 11 GPa) were determined to be in agreement with those reported for similar films grown by physical methods. Titanium and tin dioxide films displayed better wear and mechanical properties than ZnO films. [ABSTRACT FROM AUTHOR]

Folil Mapudungun is a multidimensional method, based on a communicative approach, for teaching and learning Mapuche as a second language (L2). It was designed for adult learners in a context where Mapudungun is a "language specific to the territory", a heritage language and a community language. It is also the result of twelve years of research aiming to formulate objectives, and produce and systematize contents. At present, the method is constituted by eight lessons, developed and published in a textbook. This paper presents the method content organization according to three axes: transverse organization (based on six functional and formal categories), longitudinal organization (based on discursive, cultural and methodological principles), and local organization (based on methodological principles as well). It is claimed that the use of these three axes allows us to overcome the methodology-content dichotomy, and to favor the development of the various communicative competences used in everyday life. [ABSTRACT FROM AUTHOR]

Microbial fuel cells (MFCs) harness the metabolic machinery of electro-active bacteria to transfer electrons from organic molecules to polarized anodes. In this context, increasingly higher anode surface areas have been pursued for maximizing MFC performance. In this study we prepared 3D layered Ti4O7 electrodes with different interlayer spacings (from 10 to 100 μm) but maintaining the same total void fraction (90%), so as to modify the electrode surface-to-volume ratios. This allowed us to test the hypothesis that there must be a limit in surface area per unit volume restricting the efficiency of 3D porous bio-electrochemical anodes. The lamellar scaffolds were evaluated in three-electrode cells cultured with G. sulfurreducens. Regardless of the electrode interlayer spacing or the biofilm developmental stage, the electron transfer rate was constant (0.11 pA per bacterium), with current scaling linearly with the size of the microbial population. However, maximum volumetric current densities (20 ± 0.8 kA m−3) were not obtained from electrodes with maximum surface-to-volume ratios (shorter interlayer distances), because bacterial biomass was not directly proportional to the surface area. This demonstrated that, by controlling the spacing between layers, it is possible to modulate the amount of bacteria per electrode unit volume, this ratio determining the final electrode performance. The limit obtained in surface area suggested that other effects, such as fluid dynamic constraints inside the “slit-shaped” pores, must be playing a critical role in anode performance. [ABSTRACT FROM AUTHOR]

Zinc oxide films with different average grain size are deposited on glass substrates by spray‐pyrolysis at 425 °C. Samples are characterized by XRD, UV–Vis transmittance, FE‐SEM, and electrical properties measurements. The increase in conductivity observed under 365 nm wavelength illumination is evaluated in terms of grain size. Films with small grains (120 nm) show higher response with respect to films with larger grains (230 and 300 nm). A model considering resistivity and grain size for the prediction of the response of films in terms of UV‐to‐dark conductivity ratio is proposed and validated with experimental results. [ABSTRACT FROM AUTHOR]

Comparative synthesis ways for preparing HA (Ca 10 (PO 4 ) 6 (OH) 2 ) nanoparticles in presence of hexamethylenetetramine (HMTA) and cetyltrimethylammonium bromide (CTAB) were carried out. The reactions were performed in a Teflon-lined stainless-steel reactor at 120 °C during 12 h. The effects of the additive concentration and the cooling mode (fast and slow) were analyzed. The obtained powders were characterized by X-ray Diffraction (XRD), Raman Spectroscopy, Dynamic Light Scattering (DLS) and Scanning Electron Microscopy (SEM). The two hydrothermal ways carried out for preparing HA nano powders produced a pure crystalline phase of HA. When the fast cooling mode was used, the obtained particles exhibited smaller mean particle sizes. The highest concentrations of used additives (HTMA or CTAB) resulted in opposite effect on the obtained mean particle size of HA particles. These observations were associated to the different behavior of these additives in the HA formation processes. [ABSTRACT FROM AUTHOR]

Directional freezing has been widely employed to prepare highly ordered three-dimensional (3D) porous assemblies. However, in this scenario, there is one concept that has not been extensively explored: by applying directional freezing to a nanoparticle (NP) dispersion supported on a substrate, two-dimensionally (2D) patterned films may be produced. In this study, tunable 2D-patterning of TiO2-NP dispersions on alumina substrates is demonstrated. By imposing different temperature gradients throughout the ceramic dispersion coatings, both homogeneous (non-patterned) and highly aligned patterned topologies (consisting of parallel grooves) were produced. In the case of patterned films, the orientation of the grooves was modulated from those oriented along the freezing direction to those perpendicularly oriented to the temperature gradient. Thermally induced reduction of the prepared films led to electrically conducting titanium oxide Magnéli phases. The measured resistances were strongly dependent on the orientation of the aligned patterns. To demonstrate the possibility of employing these structured films as platforms for electrical stimulation-related applications, a stimulating electronic circuit was developed and connected to the prepared films. Charge-balanced biphasic stimulus pulses with tunable current amplitudes and frequencies were successfully delivered through the conducting 2D-patterned assemblies. [ABSTRACT FROM AUTHOR]

Herein we report the characterization and photoelectrochemical behavior of nanocrystalline TiO2 films modified with some alizarin derivatives. Particularly, alizarin complexone (3-[N,N-bis(carboxymethyl)-aminomethyl]-1,2-dihydroxyanthraquinone) and its Fe(ii) and Fe(iii) metal complexes have been examined. Based on UV-Visible and Raman spectroscopic studies we proposed that AC forms a tridentate complex with titanium dioxide involving the 2-OH and (methylimino) diacetate groups, while Fe(ii) and Fe(iii) AC-complexes bind to titanium dioxide through the carbonyl (C=O) and hydroxyl (OH) groups at the 1,9 positions of the alizarin framework. These findings allow the design of different nanostructures with diverse photoelectrochemical behavior. Analysis of the j–V curves reveals a sign reversal at −90 mV and −100 mV upon the excitation of AC@TiO2 and [FeIIIAC]@TiO2 photoelectrodes, respectively, whereas [FeIIAC]@TiO2 displays only anodic photocurrents. A description involving both electronic and geometric factors to account for these differences is proposed. [ABSTRACT FROM AUTHOR]

We present 2 cm and 3.6 cm wavelength very long baseline interferometry images of the compact radio continuum sources in the nearby ultra-luminous infrared galaxy Arp220. Based on their radio spectra and variability properties, we confirm these sources to be a mixture of supernovae (SNe) and supernova remnants (SNRs). Of the 17 detected sources we resolve 7 at both wavelengths. The SNe generally only have upper size limits. In contrast all the SNRs are resolved with diameters ≥ 0.27 pc. This size limit is consistent with them having just entered their Sedov phase while embedded in an interstellar medium (ISM) of density 104 cm-3. These objects lie on the diameter-luminosity correlation for SNRs (and so also on the diameter-surface brightness relation) and extend these correlations to very small sources. The data are consistent with the relation L ∝ D-9/4. Revised equipartition arguments adjusted to a magnetic field to a relativistic particle energy density ratio of 1 % combined with a reasonable synchrotron-emitting volume filling factor of 10% give estimated magnetic field strengths in the SNR shells of ∼15-50 mG. The SNR shell magnetic fields are unlikely to come from compression of ambient ISM fields and must instead be internally generated. We set an upper limit of 7 mG for the ISM magnetic field. The estimated energy in relativistic particles, 2%-20% of the explosion kinetic energy, is consistent with estimates from models that fit the IR-radio correlation in compact starburst galaxies. [ABSTRACT FROM AUTHOR]

Zinc oxide nanorods in the form of powder or nanostructured films were synthesized by the hydrothermal method using aqueous solutions. Once the synthesis time was completed, the reaction vessel was naturally cooled or submitted to a quenching process. X-ray diffraction, Scanning Electron Microscopy and Transmission Electron Microscopy techniques were employed to characterize the crystallinity, morphology, and dimensions of the nanorods, as well as their growth direction. Suspensions of powder material were spin-coated over oxidized silicon substrates in order to obtain nanostructured layers. Photo detectors based on in-situ grown and spin-coated films were prepared in order to evaluate the influences of cooling rate and device configuration on the UV sensing characteristics. Spin-coated layers showed an excellent performance (current change by more than four orders of magnitude), better than nanorods grown directly on the substrate during the hydrothermal process. For both configurations, the sensitive layers built from quenched samples exhibited enhanced UV photoresponses when compared to the naturally cooled ones. [ABSTRACT FROM PUBLISHER]

In this article, the adequacy of syntactic descriptors used in mapuche language I discuss, in order to confront theoretically those who want to reflect its particular syntactic organization, and those who prefer to put it into universal parameters. Sustained in the "Functional Typological Grammar" of Talmy Givón (1983-1995-2001), this paper recognize the importance of formal and pragmatic properties -as well as their connection- for the study of syntax. In this basis, in addition to the discussion about the concepts in use, an analysis of mapuche grammatical categories is presented. So, the formal and pragmatic properties of "focal person" in mapuche are analized, and a corpus based study realized over seven mapuche tales is presented. Both parts of the study show that mapuche "focal person" is completely congruent with the formal and pragmatic properties of "subject". [ABSTRACT FROM AUTHOR]

Abstract: Because of the environmental concerns, the manufacture of ceramics based on lead titanate zirconate [Pb(Zr1−x Ti x )O3−PZT] has been condemned because of the lead toxicity. In this context, the electromechanical properties of sodium, potassium and lithium niobate [(Na0.5−x/2K0.5−x/2Lix)NbO3−NKLN] at the morphotropic phase boundary granted these materials the position of most suitable candidate to replace PZT. However, the production of these ceramics is rather critical mainly because of a natural tendency of forming secondary phases. To help with the studies of the synthesis of this lead-free piezoceramic, this work presents an evaluation of the crystallization of the (Na0.47K0.47Li0.06)NbO3 phase by solid-state reactions. TG-DTA, XRD, dilatometric and ferroelectric hysteresis analyses indicated that a secondary phase (K3Li2Nb5O15) crystallizes at temperatures above 850 ∘C and also during the sintering of the powders compacts at 1080 ∘C. To prevent the formation of this phase, the addition of Na2Nb2O6.nH2O microfibers obtained through a microwave hydrothermal synthesis was performed in the sintering process. After to this addition, the suppression of the K3Li2Nb5O15 phase occurred and an increase of the NKLN electrical properties was then obtained. [Copyright &y& Elsevier]

Abstract: One-dimensional nanostructures of KNbO3 have attracted a great interest in the scientific community, mainly because of their promising application as nanoelectromechanical systems (NEMS). However, the synthesis of KNbO3 structures becomes complex due to the natural tendency to form non-stoichiometric potassium niobates. In this context, we report on the crystallization of one-dimensional KNbO3 nanostructures through the reaction between Nb2O5 and KOH under microwave-assisted hydrothermal synthesis (M-H). The use of this synthesis method made possible a very fast synthesis of singlecrystalline powders. Based on SEM, TEM and XRD characterizations, the influence of the synthesis time and the reactants concentration in the structure and morphology of the resultant KNbO3 was established. The conditions that favor the crystallization of nanofingers were determined to be small amounts of Nb2O5 and short reaction times. [Copyright &y& Elsevier]

Thick films prepared with undoped nanometric SnO2 particles and with (Co, Nb, Fe)-doped SnO2 were studied with the purpose of developing oxygen and carbon monoxide gas sensors. The ceramic powders were obtained through the Pechini method. The morphological characteristics were studied with SEM and TEM, after which, they were subjected to sensitivity tests under different atmospheres. A correlation was established between the microstructure of the material, the effects of the additives, and the electrical behavior. The response of the sensor could be explained as the result of the characteristics of the intergranular potential barriers developed at intergrains. It was determined that the SnO2-doped films have a greater sensitivity between 200 °C and 350 °C. [ABSTRACT FROM AUTHOR]

The influence of aluminium on the development of the microstructure and on the electrical behaviour of the SnO2 · Co3O4 · Nb2O5 typical varistor system was studied. Two sources of Al were used, alumina (Al2O3) and boehmite (AlO(OH)). The microstructural features were characterised with scanning (SEM) and transmission (TEM) electron microscopies. The different phases present in the studied samples were also studied with XRD, EDS and electron diffraction patterns of selected areas (SAED). Particles containing Sn, Co, Al, and O were unveiled with TEM. Impedance spectroscopy measurements and current density versus electric field characteristics revealed superior electrical properties for samples with AlO(OH). The higher non-linearity ( α = 19) was achieved with the addition of 0.1% mol of boehmite. The influence of the secondary phases on the electrical properties is also addressed in this work. [ABSTRACT FROM AUTHOR]

In the automatic diagnosis of ocular toxoplasmosis (OT), Deep Learning (DL) has arisen as a powerful and promising approach for diagnosis. However, despite the good performance of the models, decision rules should be interpretable to elicit trust from the medical community. Therefore, the development of an evaluation methodology to assess DL models based on interpretability methods is a challenging task that is necessary to extend the use of AI among clinicians. In this work, we propose a novel methodology to quantify the similarity between the decision rules used by a DL model and an ophthalmologist, based on the assumption that doctors are more likely to trust a prediction that was based on decision rules they can understand. Given an eye fundus image with OT, the proposed methodology compares the segmentation mask of OT lesions labeled by an ophthalmologist with the attribution matrix produced by interpretability methods. Furthermore, an open dataset that includes the eye fundus images and the segmentation masks is shared with the community. The proposal was tested on three different DL architectures. The results suggest that complex models tend to perform worse in terms of likelihood to be trusted while achieving better results in sensitivity and specificity. [ABSTRACT FROM AUTHOR]

Results on the characterization of photoluminescent CaCu3Ti4O12-based films, prepared from a sol–gel precursor and heat treated at 700°C, are reported for the first time. The samples showed two emission bands at 554 and 800 nm when excited with a 488 nm Ar-ion laser. The photoluminescent emission measured at room temperature in thin films was attributed to complex vacancy clusters. The films consisted of CaCu3Ti4O12 with traces of TiO2, CuO, and CaTiO3 and showed porous structures with an average particle size of 50 nm under atomic force microscopy resolution. [ABSTRACT FROM AUTHOR]

The complete I–V characteristics of SnO2-based varistors, particularly of the Pianaro system SCNCr consisting in 98.9%SnO2+1%CoO+0.05%Nb2O5+0.05%Cr2O3, all in mol%, have been seldom reported in the literature. A comparative study at low and high currents of the nonohmic behavior of SCNCr- and ZnO-based varistors (modified Matsuoka system) is proposed in this work. The SCNCr system showed higher nonlinearity coefficients in the whole range of measured current. The electrical breakdown field ( Eb) was twice as high for the SCNCr system (5400 V/cm) than for the ZnO varistor (2600 V/cm) due to a smaller average grain size of the former (4.5 μm) with respect to the latter (8.5 μm). Nevertheless, we consider that another important factor responsible for the high Eb in the SCNCr system is the great number of electrically active interfaces (85%) as determined with electrostatic force microscopy (EFM). It was also established that the SCNCr system might be produced in disks of smaller dimensions than that of commercial ZnO-based product, with a 5.0 cm−1 minimal area–volume ( A/V) ratio. The SCNCr reached the saturation current in a short time because of the high resistivity of the grains, which is five times higher than that of the grains in ZnO-based varistors. [ABSTRACT FROM AUTHOR]