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Global concrete production, reaching 14×1013m3/year, raises environmental concerns due to the resource-intensive nature of ordinary Portland cement (OPC) manufacturing. Simultaneously, 32.7×109 kg/year of expanded polystyrene (EPS) waste poses ecological threats. This research explores the mechanical behavior of lightweight concrete (LWAC) using recycled EPS manufactured with a hybrid cement mixture (OPC and alkali-activated cement). These types of cement have been shown to improve the compressive strength of concrete, while recycled EPS significantly decreases concrete density. However, the impact of these two materials on the LWAC mechanical behavior is unclear. LWAC comprises 35% lightweight aggregates (LWA)-a combination of EPS and expanded clays (EC) - and 65% normal-weight aggregates. As a cementitious matrix, this LWAC employs 30% OPC and 70% alkaline-activated cement (AAC) based on fly ash (FA) and lime. Compressive strength tests after 28 curing days show a remarkable 48.8% improvement, surpassing the ACI 213R-03 standard requirement, which would allow this sustainable hybrid lightweight aggregate concrete to be used as structural lightweight concrete. Also obtained was a 21.5% reduction in density; this implies potential cost savings through downsizing structural elements and enhancing thermal and acoustic insulation. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy reveal the presence of C-S-H, C-(A)-S-H, and N-A-S-H gels. However, anhydrous products in the hybrid LWAC suggest a slower reaction rate. Further investigation into activator solution dosage and curing temperature is recommended for improved mechanical performance on the 28th day of curing. This research highlights the potential for sustainable construction incorporating waste and underscores the importance of refining activation parameters for optimal performance.

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To complement previous results, an analysis of the chemical and morphological properties of babassu fibers (Attalea speciosa Mart. ex Spreng.) was conducted in order to evaluate their potential as reinforcements in the production of composites with epoxy matrix. The diameter distribution was analyzed in a sample of one hundred fibers, allowing the verification of its variation. The determination of the chemical properties involved experimental analyses of the constituent index and X-ray diffraction. The diffractogram was used to calculate the crystallinity index and the microfibril angle, which are crucial parameters that indicate the consistency of the mechanical properties of babassu fibers and the feasibility of their use in composites. The results revealed that babassu fiber has a chemical composition, with contents of 28.53% lignin, 32.34% hemicellulose, and 37.97% cellulose. In addition, it showed a high crystallinity index of 81.06% and a microfibril angle of 7.67°. These characteristics, together with previous results, indicate that babassu fibers have favorable chemical and morphological properties to be used as reinforcements in composites, highlighting its potential as an important material for applications in technology areas.

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Formulations of biodegradable films using macrocarpa peach palm flour (low amylose starch), chitosan and glycerol, were developed and the effects of the drying temperature on films by assessing their physicochemical, mechanical, barrier, optical, structural, antioxidant properties, and the biodegradability in soil were evaluated. Chitosan enhanced the mechanical properties of the films, but they showed no antimicrobial activity against the tested food-borne pathogens, except for Listeria monocytogenes, for which the inhibition zone was from 0.1 to 0.6 cm. Films with higher concentrations of peach palm flour are opaquer, with better antioxidant characteristics and content of phenolic compounds compared to films made with lower concentrations of flour. The films presented a yellowish color because of the carotenoids found in peach palm flour, 29.63 µg 100 g-1, and exhibited a C-type X-ray pattern, characteristic peak of materials where amylose and amylopectin are present. After 15 days in soil, the films lost 30% of their initial weight. Therefore, these results suggest that the development of films as food preservative is a promising field and that the material used in the study are suitable for their formulation.

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Maleic acid was studied by Raman spectroscopy and powder synchrotron X-ray diffraction (XRD) under high pressure conditions by using a diamond anvil cell. The Raman spectroscopy measurements were performed from ambient pressure up to 9.2 GPa in the 100-3200 cm-1 spectral range. While the XRD measurements were performed up to 10.1 GPa. Here we present the pressure-dependence behavior from both the Raman modes and cell parameters. Maleic acid lattice parameters decrease anisotropically as a function of pressure and a reduction of 27% in the volume of the unit cell was observed. Modifications in the material's compressibility were observed at around 2 and 6 GPa.

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Fatty acid binding proteins (FABPs) are responsible for the long-chain fatty acids (FAs) transport inside the cell. However, despite the years, since their structure is known and the many studies published, there is no definitive answer about the stages of the lipid entry-exit mechanism. Their structure forms a ß -barrel of 10 anti-parallel strands with a cap in a helix-turn-helix motif, and there is some consensus on the role of the so-called portal region, involving the second α -helix from the cap ( α 2), ß C- ß D, and ß E- ß F turns in FAs exchange. To test the idea of a lid that opens, we performed a soaking experiment on an h-FABP crystal in which the cap is part of the packing contacts, and its movement is strongly restricted. Even in these conditions, we observed the replacement of palmitic acid by 2-Bromohexadecanoic acid (Br-palmitic acid). Our MD simulations reveal a two-step lipid entry process: (i) The travel of the lipid head through the cavity in the order of tens of nanoseconds, and (ii) The accommodation of its hydrophobic tail in hundreds to thousands of nanoseconds. We observed this even in the cases in which the FAs enter the cavity by their tail. During this process, the FAs do not follow a single trajectory, but multiple ones through which they get into the protein cavity. Thanks to the complementary views between experiment and simulation, we can give an approach to a mechanistic view of the exchange process.

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Drying rice in a single layer in a silo-dryer-aerator allows uniform drying. The objective of this study was to evaluate the physical, physicochemical, and morphological quality of rice grain cultivars (IRGA 424, BRS Pampeira, and Guri INTA) in the lower (initial time) and upper (final time) layers in a silo-dryer-aerator, employing single-layer loading at low temperatures, using the methods of near-infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, and multivariate statistical analysis. Drying rice in silo-dryer-aerator attenuated the moisture diffusivity in the grains, minimizing its effects on the physical, physicochemical, and morphological properties of the grains. However, the physicochemical constituents and morphology of starch were preserved by the low drying temperatures, mainly in the lower layers throughout the 2-month drying. The rice grains of the Guri INTA and BRS Pampeira cultivars were the most resistant to drying and showed greater uniformity on the final quality.

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The plastic phase of cyclohexane (polymorph I) was studied by Kahn and co-workers, without achieving a satisfactory determination of the atomic coord-inates [Kahn et al. (1973). Acta Cryst. B29, 131-138]. The positions of the C atoms cannot be determined directly as a consequence of the disorder in a high-symmetry space group, an inherent feature of plastic materials. Given this situation, the building of a polyhedron describing the disorder was the main tool for determining the molecular structure in the present work. Based on the shape of reflections {111}, {200} and {113} in space group Fm 3 m, we assumed that cyclohexane is disordered through the action of rotation group 432. The polyhedral cluster of disordered molecules is then a rhombic dodecahedron centred on the nodes of an fcc Bravais lattice. The vertices of this polyhedron are the positions of C atoms for the cyclohexane molecule, which is disordered over 24 positions. With such a model, the asymmetric unit is reduced to two C atoms placed on special positions, and an acceptable fit between the observed and calculated structure factors is obtained.

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Aiming of self-sustainable production, the search for biodegradable and biocompatible materials has brought with it the need to know the physicochemical and dielectric characteristics of polysaccharide-based composite structures, which can be used as important and promising raw materials for biotechnology and electronic industries. Galactomannans are polysaccharides, extracted from seeds and microbiological sources, consisting of mannose and galactose. In this context, this work aimed to extract, purify and characterize by XRD, FTIR and impedance spectroscopy galactomannan obtained from seeds of Adenanthera pavonina L. The purification process was made with ethyl alcohol at concentrations of 70, 80 and 90 %. Polymeric films were prepared by solvent slow evaporation at low temperatures. XRD measurements revealed that Galactomannan from Adenanthera pavonina L., after purification, has a semi-crystalline structure due to the identification of two peaks the first between 5.849° and 6.118° and the second between 20.011° and 20.247°. FTIR spectra showed the functional groups associated with monosaccharides of the galactomannan from Adenanthera pavonina L. seeds, as well as the typical polysaccharide bands and peaks, confirmed by literature data. The impedance results give an increment on the state-of-the-art of this biomaterial by showing the existence of dielectric relaxations, independent of the degree of purification, using the dielectric modulus formalism. The permittivity analysis reveals the presence of water in the structure of the film, whose dipoles contribute to the relatively high value of the dielectric constant. From the results obtained, it can be concluded that purified galactomannan has the potential for possible applications in the electronics industry as a green and eco-friendly dielectric material.

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Furofuran lignanes show important biological activities for the treatment of infectious diseases, inflammatory and metabolic pathologies. They have been isolated from leaves and barks of many plants. In Chile the native conifer Araucaria araucana produces eudesmin, matairesinol, secoisolariciresinol and lariciresinol in stemwood, branchwood and knotwood. These compounds were previously isolated by laborious flash chromatography on silica gel. Here we report the easy isolation of eudesmin by soxhlet extraction from milled knots of Araucaria araucana with hexane, followed by cryo-crystallization at -20 °C. Upon bromination of the isolated eudesmin epimerization at one benzylic position occurs, giving epieudesmin and the corresponding mono and di-brominated derivatives. The structures were determined by 1D, 2D NMR and X-ray diffraction. The analysis of products against Candida yeast showed that eudesmin has a moderate activity against different strains of Candida from 62.5 to 500 µg/mL. This activity decreases for epieudesmin, while bromine derivatives are not active.

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To increase hydration properties and soluble fiber content, okara with different moisture contents (30, 35, and 40%) was extruded in single-screw equipment, keeping the temperature (120 °C) and screw speed (115 rpm) fixed. The physical, chemical, and techno-functional properties of extruded and non-extruded okara (control) were evaluated. The microstructure, color, chemical composition, and techno-functional properties of okara were altered after extrusion. The extruded samples showed general microstructure aspects similar between them, with an irregular and rough surface, striated parts, orifices, and some agglomerated particles with distorted, compact, and amorphous appearance, different from control. Among the modified samples, okara extruded with 30% moisture showed more intense changes in relation to the samples extruded with 35 and 40% moisture. Based on the results, it can be inferred that okara extruded with 35% moisture is the most suitable. Under this condition, there was an increase of 80% in soluble fiber content, 45% in water absorption and holding capacity and 11% in solid stability in water, the maintenance of swelling and oil absorption and holding capacities and the reduction of protein solubility in water. X-ray diffraction analysis showed that crystalline phase was affected by extrusion.

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