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Background: Systemic lupus erythematosus (SLE) is a chronic, systemic, autoimmune disease of multifactorial origin. There are no previous studies in Colombia describing juvenile SLE (jSLE) prevalence, prompting this demographic description. Objective: This study aimed for prevalence calculation and epidemiologic analysis of jSLE) in Colombian patients, ages 0–19, from 2015 to 2019. Methods: This descriptive, cross-sectional study searched the Colombian Ministry of Health database for codes of the International Classification of Diseases, 10th revision (ICD-10) associated with jSLE to estimate the disease prevalence for the total population and for specific age groups at national and regional levels. Calculations used intercensal estimates of population based on the projections of the national statistics administrative department (DANE) from the most recent census. This paper presents a sociodemographic analysis of patients with jSLE. Results: The study identified in Colombia, from 2015 to 2019, 3680 cases with jSLE as the principal diagnosis. Calculated prevalence of jSLE was 25 cases per 100,000 population, with highest frequency in ages 15–19 and females (84%), with a female:male ratio of 5.1:1. Conclusion: Estimated prevalence of jSLE in Colombia is at the highest limit of worldwide findings. Consistent with reports in the literature, the disease involves females more frequently than males. [ABSTRACT FROM AUTHOR]

High-purity TiO2 and CuO powders were synthesized by the Pechini method, an inexpensive and easy-to-implement procedure to synthetize metal oxides. The variables of synthesis were the ethylene glycol:citric acid molar ratio and the pH. High reproducibility of the anatase and tenorite phase was obtained for all synthesis routes. The degree of purity of the powders was confirmed by XRD, FTIR, UV-Vis absorption and XPS spectra. SEM and TEM images revealed the powders are composed of micrometer grains that can have a spherical shape (only in the TiO2) or formed by a non-compacted nanocrystalline conglomerate. FTIR spectra only displayed vibrational modes associating TiO2 and CuO with nanoparticle behavior. UV-Vis absorption spectra revealed the values of maximum absorbance percentage of both systems are reached in the ultraviolet region, with percentages above 83% throughout the entire visible light spectrum for the CuO system, a relevant result for solar cell applications. Finally, XPS experiments allow the observation of the valence bands and the calculation of the energy bands of all oxides. [ABSTRACT FROM AUTHOR]

This work shows the influence of different thermal treatment conditions on the growth of copper oxide nanostructures, which are formed by subjecting a 388 ± 7 nm thick copper film to a temperature of 400 °C in air atmosphere. Thin layers of copper were grown on silicon substrates, using thermal evaporation technique. The parameters involved in this study are: The initial condition for which the samples reach 400 °C, with ramp and without heating ramp and the annealing time. Based on the results obtained by scanning electron microscopy and X-ray diffraction, it was possible to establish that thermal treatments generate a change in both the crystalline structure and the morphology of the Cu layer, mediated by the formation of nanostructures of mixed character, composed of a mixture of phases referring to Cu metallic, Cuprite (Cu2O) and Tenorite (CuO), the CuO being the majority phase in all nanostructured samples. The average grain size range is between 21 - 53 nm and depends on the type of heat treatment. Furthermore, the optical properties of the material were evaluated by UV-VIS spectroscopy, showing bands in both regions (ultraviolet and visible), which were analyzed by the Tauc extrapolation method; obtaining values for the band prohibited between (1.40 - 1.49) eV associated with a P-type conductivity of this class of semiconductor metal oxides. [ABSTRACT FROM AUTHOR]

This study is based on the need to consolidate environmentally friendly technology to overcome pollution problems caused by conventional refrigerators. Compounds based on La(Fe,Si) 13 have attracted much attention in many fields of industry as low cost materials as well as bright prospects for practical applications. The alloys obtained in this study are based on the LaFe 11.57 Si 1.43 and LaFe 11.57 Si 1.43 H systems. These alloys were produced by melt-spinning of samples initially melted in an electric arc furnace and homogenized by heat treatment at 1050 °C for 2 h. LaFe 11.57 Si 1.43 alloys to be hydrogenated with very little amount of 0.9 MPa of 5% H2/Ar gas and heat-treated at 723 K for one hour. An analysis of the crystal structure using X-ray diffraction measurements revealed that all alloys showed La-Fe-Si (1:13 phase) as the majority one with 85.8 wt% and 83.1 wt% for LaFe 11.57 Si 1.43 and LaFe 11.57 Si 1.43 H respectively. The hyperfine and magnetic behavior of the alloys were studied by means of Mössbauer spectroscopy, and it was observed that the LaFe 11.57 Si 1.43 alloy was fitted with a singlet and a doublet corresponding to 1:13 phase with a total spectral area of 72.5%, and in the LaFe 11.57 Si 1.43 H alloy exhibited a ferromagnetic behavior at room temperature with a hyperfine field of 19.4 T. Using vibrating sample magnetometry, it was demonstrated that the essential magnetic parameters to optimize the magnetocaloric effect, Curie temperature, and saturation magnetization at room temperature, significantly improved from 228.23 K to 308.1 K and 37.03 A m2kg−1 to 120 A m2kg−1, respectively, with the addition of hydrogen. Endothermic peaks possibly associated with first-order magnetic phase transition were found in each of the La-Fe-Si alloys using differential scanning calorimetry, coinciding with its T C value of 315.1 K. These results demonstrate that hydrogenation under a poor hydrogen gas atmosphere is an effective and safer method for improve the magnetocaloric properties of the LaFe 11.57 Si 1.43 system. • A high concentration of the 1:13 phase was successfully synthesized. • The LaFe11.57Si 1.43 H alloy exhibited ferromagnetic behaviors at room temperature. • Hydrogenation under a poor hydrogen gas atmosphere is an effective method. • Lattice expansion had a positive influence on the magnetic and thermal properties of La-Fe-Si-H. [ABSTRACT FROM AUTHOR]

Al/CuO energetic structure are attractive materials due to their high thermal output and propensity to produce gas. They are widely used to bond components or as next generation of MEMS igniters. In such systems, the reaction process is largely dominated by the outward migration of oxygen atoms from the CuO matrix toward the aluminum layers, and many recent studies have already demonstrated that the interfacial nanolayer between the two reactive layers plays a major role in the material properties. Here we demonstrate that the ALD deposition of a thin ZnO layer on the CuO prior to Al deposition (by sputtering) leads to a substantial increase in the efficiency of the overall reaction. The CuO/ZnO/Al foils generate 98% of their theoretical enthalpy within a single reaction at 900 °C, whereas conventional ZnO-free CuO/Al foils produce only 78% of their theoretical enthalpy, distributed over two distinct reaction steps at 550 °C and 850 °C. Combining high-resolution transmission electron microscopy, X-ray diffraction, and differential scanning calorimetry, we characterized the successive formation of a thin zinc aluminate (ZnAl2O4) and zinc oxide interfacial layers, which act as an effective barrier layer against oxygen diffusion at low temperature. [ABSTRACT FROM AUTHOR]

Epitaxial strain alters the physicalproperties of thin films grown on single crystal substrates. Thinfilm oxides are particularly apt for strain engineering new functionalitiesin ferroic materials. In the case of La2/3Ca1/3MnO3(LCMO) thin films, here we show the first experimentalimages obtained by electron holography demonstrating that epitaxialstrain induces the segregation of a flat and uniform nonferromagneticlayer with antiferromagnetic (AFM) character at the top surface ofa ferromagnetic (FM) layer, the whole film being chemical and structurallyhomogeneous at room temperature. For different substrates and growthconditions the tetragonality of LCMO at room temperature, definedas τ = |c– a|/a, is the driving force for a phase coexistence above anapproximate critical value of τC≈ 0.024.Theoretical calculations prove that the increased tetragonality changesthe energy balance of the FM and AFM ground states in strained LCMO,enabling the formation of magnetically inhomogeneous states. Thiswork gives the key evidence that opens a new route to synthesize strain-inducedexchanged-biased FM–AFM bilayers in single thin films, whichcould serve as building blocks of future spintronic devices. [ABSTRACT FROM AUTHOR]

The impacts on the morphological, electrical and hardness properties of thermoplastic polyurethane (TPU) plates using multi-walled carbon nanotubes (MWCNTs) as reinforcing fillers have been investigated, using MWCNT loadings between 1 and 7 wt%. Plates of the TPU/MWCNT nanocomposites were fabricated by compression molding from extruded pellets. An X-ray diffraction analysis showed that the incorporation of MWCNTs into the TPU polymer matrix increases the ordered range of the soft and hard segments. SEM images revealed that the fabrication route used here helped to obtain TPU/MWCNT nanocomposites with a uniform dispersion of the nanotubes inside the TPU matrix and promoted the creation of a conductive network that favors the electronic conduction of the composite. The potential of the impedance spectroscopy technique has been used to determine that the TPU/MWCNT plates exhibited two conduction mechanisms, percolation and tunneling conduction of electrons, and their conductivity values increase as the MWCNT loading increases. Finally, although the fabrication route induced a hardness reduction with respect to the pure TPU, the addition of MWCNT increased the Shore A hardness behavior of the TPU plates. [ABSTRACT FROM AUTHOR]

We have combined optical and focusedion beam lithographies toproduce large aspect-ratio (length-to-width >300) single-crystalnanowiresof La2/3Ca1/3MnO3that preserve theirfunctional properties. Remarkably, an enhanced magnetoresistance valueof 34% in an applied magnetic field of 0.1 T in the narrowest 150nm nanowire is obtained. The strain release at the edges togetherwith a destabilization of the insulating regions is proposed to accountfor this behavior. This opens new strategies to implement these structuresin functional spintronic devices. [ABSTRACT FROM AUTHOR]

A modification to the fully thermally coupled distillation system, or Petlyuk column, in which a postfractionator is added has recently been considered. The modified structure incorporates the postfractionator aiming for a better match in the composition of the interlinking stages of the Petlyuk column. In this paper we present a design method for the modified thermally coupled system with postfractionator. A shortcut method is used to provide the minimum reflux conditions of the system, and the boundary value method is used to complete the design task. The effectiveness of the design method is shown through the application to several case studies. The effect of the postfractionator on the performance of the Petlyuk system is also analyzed. [ABSTRACT FROM AUTHOR]

La conmutación resistiva, referida en inglés como resistive switching (RS), es un fenómeno físico presente en materiales dieléctricos, en estado sólido y en configuración tipo capacitor metal-aislantemetal (MIM, siglas en ingles), los cuales pueden presentar cambios reversibles de estados resistivos metaestables cuando son sometidos a campos eléctricos (o voltajes) externos. Estados resistivos específicos, conocidos como estados de baja (LRS, siglas en ingles) y alta resistencia (HRS, siglas en inglés), logran ser mantenidos por el dieléctrico en ausencia de tensiones eléctricas, lo que permiten ser empleados en dispositivos de lectura, escritura, transferencia y almacenamiento de información no volátiles. En el presente trabajo nosotros estudiamos la variabilidad de los estados LRS y HRS en un dispositivos verticales de óxidos multifuncionales de en forma de películas delgadas depositados sobre sustratos de LSAT usando la técnica de sputtering en función del electrodo superior de y. Se realizaron pruebas de caracterización estructurales, además de curvas corriente vs voltaje (I-V) y su proceso de electroformación, curvas de resistencia vs tiempo (RS), tiempo de retención y capacitancia vs voltaje donde se logró observar la estabilidad del efecto de conmutación resistiva y la asimetría del efecto en función del electrodo superior; siendo más estable y simétrico en las muestras de electrodo superior pero con menor diferencia entre estados respecto a la muestra con el electrodo superior de el cual presentó asimetría en su comportamiento de conmutación resistiva. Por tanto, se demuestra para este tipo de dispositivos, que el es mejor candidato como electrodo dada su estabilidad frente a la variabilidad de los estados HRS y LRS lo cual es de gran relevancia para la implementación de esta tecnología. [ABSTRACT FROM AUTHOR]

Reactive nanolaminates are stacked nanolayers of metal and oxide that undergo exothermic, selfpropagating reactions when layer mixing is induced by an external energy source. These materials are of growing interest as customized heat and gas sources for materials, chemical, and biochemical communities. They can be easily integrated within microscale devices to address various potential applications as micro-thermal sources, micro-actuators, in-situ welding, local enhancement of chemical reactions, nano-sterilization and controlled cell apoptosis. We present here a DC-magnetron sputtering process to engineer Al/CuO nanolaminates. In all cases the layers have uniform thicknesses that are separated by atomically resolved interfacial regions [1,2]. We explore a novel method for enhancing the reactivity of Al/CuO nanolaminates and uses a combination of structural and chemical characterization techniques to uncover the fundamental mechanism responsible for this enhancement. Considering 7 bilayers Al/CuO nanolaminates, we show that the deposition of only 5 nm of metallic Cu on the 100 nm thick Al layer prior to the deposition of the 200 nm thick CuO layers, leads to an increase of the flame propagation velocity by a factor of 1.6. In addition, we demonstrate that the ALD deposition of a thin ZnO layer on the CuO prior to Al deposition leads to a substantial increase in the efficiency of the overall reaction. These results represent a substantial contribution to the field of Al-based thin film community by bringing not only a new method to optimize devices but also a fundamental mechanistic understanding of the mechanism that control of the properties of these materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • A ferric oxide from steel industry is used as precursor material. • Hematite submicron particles were prepared through wet synthesis method. • Structural and optical study was carried out by spectroscopy characterization techniques. • The magnetic characteristic in the samples were carried out using SQUID. Hematite submicron particles were synthesized using oil-contaminated ferric oxide precursor obtained from the hot-rolled steel industry in Colombia. The samples received are difficult to recycle for the steel industry, which, due to their poor disposal, causes irreparable environmental damage. Here we propose a synthetic route to obtain functional magnetic particles with this residue. First, a series of washes with solvent and alcohols were proposed, thus achieving the total removal of the oil. X-ray diffraction and Mössbauer spectroscopy show that the as received sample consists of different iron phases, with wüstite being the majority phase. After the synthesis process, the hematite phase was present as the majority phase with ∼92 wt%. FTIR, UV–Vis, and SQUID measurements was carried out to study the structural, optical and magnetic properties of the samples. This methodology is a viable alternative to give added value to this waste to improve the management of this by-product. [ABSTRACT FROM AUTHOR]

The rare-earth-free MnAlC alloy is currently considered a very promising candidate for permanent magnet applications due to its high anisotropy field and relatively high saturation magnetization and Curie temperature, besides being a low-cost material. In this work, we presented a simple fabrication route that allows for obtaining a magnetically enhanced bulk τ-MnAlC magnet. In the fabrication process, an electric arc-melting method was carried out to melt ingots of MnAlC alloys. A two-step solution treatment at 1200 °C and 1100 °C allowed us to synthesize a pure room-temperature ε-MnAlC ingot that completely transformed into τ-MnAlC alloy, free of secondary phases, after an annealing treatment at 550 °C for 30 min. The Rietveld refinements and magnetization measurements demonstrated that the quenched process produces a phase-segregated ε-MnAlC alloy that is formed by two types of ε-phases due to local fluctuation of the Mn. Room-temperature hysteresis loops showed that our improved τ-MnAlC alloy exhibited a remanent magnetization of 42 Am2/kg, a coercive field of 0.2 T and a maximum energy product, (BH)max, of 6.07 kJ/m3, which is higher than those reported in previous works using a similar preparation route. Experimental evidence demonstrated that the synthesis of a pure room-temperature ε-MnAlC played an important role in the suppression of undesirable phases that deteriorate the permanent magnet properties of the τ-MnAlC. Finally, magnetic images recorded by Lorentz microscopy allowed us to observe the microstructure and magnetic domain walls of the optimized τ-MnAlC. The presence of magnetic contrasts in all the observed grains allowed us to confirm the high-quality ferromagnetic behavior of the system. [ABSTRACT FROM AUTHOR]

Neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and C-Reactive Protein (CRP) are markers of inflammation that are elevated in bipolar disorder (BD) and are also related to a higher risk of metabolic syndrome (MetS). This study aimed at investigating for the first time the association between NLR, PLR, and CRP and the metabolic status in BD. We assessed the association between biomarkers and the metabolic status: number of metabolic risk factors, presence of MetS, insulin sensitivity (Quantitative Insulin Sensitivity Check Index, QUICKI) and insulin resistance (Homeostatic Model Assessment for Insulin Resistance, HOMA-IR index), in a sample of 219 outpatients with BD. 25.9% of the sample met the criteria for MetS. High levels of CRP were found in 12% of the sample. Older age, low PLR, high NLR, and high CRP levels significantly predicted a higher number of MetS risk factors (p < 0.001). Older age and low PLR were associated with a greater likelihood of developing MetS (p = 0.007). Although further studies are needed to replicate and validate these findings, inflammatory biomarkers as CRP, PLR and NLR could be useful tools to identify patients with a BD at risk for a metabolic adverse outcome. [ABSTRACT FROM AUTHOR]

Thermite multilayered films have the potential to be used as local high intensity heat sources for a variety of applications. Improving the ability of researchers to more rapidly develop Micro Electro Mechanical Systems devices based on thermite multilayer films requires predictive modeling in which an understanding of the relationship between the properties (ignition and flame propagation), the multilayer structure and composition (bilayer thicknesses, ratio of reactants, and nature of interfaces), and aspects related to integration (substrate conductivity and ignition apparatus) is achieved. Assembling all these aspects, this work proposes an original 2D diffusion-reaction modeling framework to predict the ignition threshold and reaction dynamics of Al/CuO multilayered thin films. This model takes into consideration that CuO first decomposes into Cu2O, and then, released oxygen diffuses across the Cu2O and Al2 O3 layers before reacting with pure Al to form Al2O3. This model is experimentally validated from ignition and flame velocity data acquired on Al/CuO multilayers deposited on a Kapton layer. This paper discusses, for the first time, the importance of determining the ceiling temperature above which the multilayers disintegrate, possibly before their complete combustion, thus severely impacting the reaction front velocity and energy release. This work provides a set of heating surface areas to obtain the best ignition conditions, i.e., with minimal ignition power, as a function of the substrate type. [ABSTRACT FROM AUTHOR]