Turbulent structures in the flow through compound meandering channels

River engineeringNumerical modelling in river engineerin

Implications of Halo Inside-out Growth on the X-Ray Properties of Nearby Galaxy Systems within the Preheating Scenario

We present an entirely analytic model for a preheated, polytropic intergalactic medium in hydrostatic equilibrium within a NFW dark halo potential in which the evolution of the halo structure between major merger events proceeds inside-out by accretion. This model is used to explain, within a standard $\Lambda$CDM cosmogony, the observed X-ray properties of nearby relaxed, non-cooling flow groups and clusters of galaxies. We find that our preferred solution to the equilibrium equations produces scaling relations in excellent agreement with observations, while simultaneously accounting for the typical structural characteristics of the distribution of the diffuse baryons. In the class of preheating models, ours stands out because it offers a unified description of the intrahalo medium for galaxy systems with total masses above \sm 2\times 10^{13}\msun, does not produce baryonic configurations with large isentropic cores, and reproduces faithfully the observed behavior of the gas entropy at large radii. All this is achieved with a moderate level of energy injection of about half a keV, which can be easily accommodated within the limits of the total energy released by the most commonly invoked feedback mechanisms, as well as with a polytropic index of 1.2, consistent with both many observational determinations and predictions from high-resolution gas-dynamical simulations of non-cooling flow clusters. More interestingly, our scheme offers a physical motivation for the adoption of this specific value of the polytropic index, as it is the one that best ensures the conservation after halo virialization of the balance between the total specific energies of the gas and dark matter components for the full range of masses investigated.Comment: 18 pages, 11 figures, accepted for publication in the Astrophysical Journa

Switching Pattern Improvement for One-Cycle Zero-Integral-Error Current Controller

[EN] The one-cycle current control is a non-linear technique based on the cycle-by-cycle calculation of the ON time of the power converter switches. Its application is not common in tracking fast-changing reference currents, due to the necessity of fast and accurate measurements, and high-speed computing. In a previous study, a one-cycle digital current controller based on the minimization of the integral error of the current was developed and applied to the control of a three-phase shunt active power filter. In the present work, the one-cycle controller has been improved by proposing a new switching pattern. It allows an easy implementation that reduces the critical computational cost and avoids the main drawbacks of the previous implementation. The controller has been applied in a three-leg four-wire shunt active power filter, including a stability analysis considering the proposed switching pattern. Simulated and experimental results are presented to validate the proposed controller.Orts-Grau, S.; Balaguer-Herrero, P.; Alfonso-Gil, JC.; Martínez-Márquez, CI.; Martínez-Navarro, G.; Gimeno Sales, FJ.; Segui-Chilet, S. (2022). Switching Pattern Improvement for One-Cycle Zero-Integral-Error Current Controller. IEEE Access. 10:158-167. https://doi.org/10.1109/ACCESS.2021.31377581581671

Structural changes in biscuits made with cellulose emulsions as fat replacers

[EN] Biscuits are a popular baked cereal food much appreciated by consumers. In the last few years, cellulose derivatives have been successfully used as fat replacers in biscuits. In this way, not only is the total amount of fat reduced but also the saturated fatty acids and the trans fatty acids are eliminated. The aim of this study is to increase understanding of the functionality of different cellulose ether emulsions used as fat replacers in biscuits. For this purpose, three emulsions with different cellulose ethers were designed: hydroxypropyl methylcellulose, methylcellulose and methylcellulose with greater methoxyl substitution (MCH). The microstructure and textural properties of the doughs and biscuits prepared with these emulsions were studied and the effects of cellulose types and glycerol as textural improver were also analysed. The results showed that the incorporation of glycerol in the doughs made with methylcellulose and hydroxypropyl methylcellulose cellulose emulsions seems to make the dough softer, bringing the values closer to those of the control dough; however, this effect disappears once the dough is baked. The presence of glycerol does not seem to have an effect on the hardness of the doughs and biscuits made using the methylcellulose with greater methoxyl substitution (MCH) emulsion.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The authors are grateful to the Spanish Ministry of Economy and Competitiveness for financial support (AGL2015-68923-C2) and gratefully acknowledge the financial support of EU FEDER funds.Teresa Sanz; Quiles Chuliá, MD.; Salvador Alcaraz, A.; Hernando Hernando, MI. (2017). Structural changes in biscuits made with cellulose emulsions as fat replacers. Food Science and Technology International. 23(6):480-489. https://doi.org/10.1177/1082013217703273S48048923

Experimental and numerical investigation of an axisymmetric supersonic jet

21 pages, 10 figures, 2 tables.A comprehensive study of a steady axisymmetric supersonic jet of CO2, including experiment, theory, and numerical calculation, is presented. The experimental part, based on high-sensitivity Raman spectroscopy mapping, provides absolute density and rotational temperature maps covering the significant regions of the jet: the zone of silence, barrel shock, Mach disk, and subsonic region beyond the Mach disk. The interpretation is based on the quasi-gasdynamic (QGD) system of equations, and its generalization (QGDR) considering the translational–rotational breakdown of thermal equilibrium. QGD and QGDR systems of equations are solved numerically in terms of a finite-difference algorithm with the steady state attained as the limit of a time-evolving process. Numerical results show a good global agreement with experiment, and provide information on those quantities not measured in the experiment, like velocity field, Mach numbers, and pressures. According to the calculation the subsonic part of the jet, downstream of the Mach disk, encloses a low-velocity recirculation vortex ring.This research was supported by the Spanish Dirección General de Investigación Científica y Enseñanza Superior (DGICYES), Research Projects PB94{1526 and PB97{1203, and by the Fund for Fundamental Investigations of the Russian Academy of Sciences N 98-01-00155.Peer reviewe

A New Highly Selective Chromogenic and Fluorogenic Chemosensor for Copper (II)

[EN] A new fluorogenic and chromogenic probe (L) for the selective, sensitive and naked-eye detection of Cu2+ is reported. Complexation constant, complex stoichiometry and quantum chemical (DFT) calculation for Cu2+ complex has been determined. Also, detection limits and the selectivity in front of other divalent and trivalent cations have been evaluated.This research was supported by the Agencia Nacional de Ciencia y Tecnologia (ANCyT) of Argentina-PICT 2014 No. 1587 and by the Universidad Nacional del Litoral, Santa Fe, Argentina.Quindt, MI.; Gutiérrez, LG.; Kneeteman, MN.; Mancini, P.; Parra Alvarez, M.; Gil Grau, S.; Costero, AM. (2018). A New Highly Selective Chromogenic and Fluorogenic Chemosensor for Copper (II). Letters in Organic Chemistry. 15(8):659-664. https://doi.org/10.2174/1570178615666180102155804S65966415

Garnierite Mineralization from Falcondo Ni-Laterite Deposit (Dominican Republic)

Mine geologists use the term "garnierite" for the green Ni-rich silicate minerals that occur in many Ni-laterite deposits. However, garnierite is not a mineral species recognized by the Commission on New Mineral and Mineral Names (CNMMN). Actually, garnierite is a general name for the NiMg hydrosilicates that usually occur as an intimate mixture that commonly includes two or more of the following minerals: serpentine, talc, sepiolite, smectite, and chlorite (e.g. Brindley and Hang, 1973; Springer, 1974; Brindley et al., 1979; Gleeson et al., 2004)

Structural and functional evidence for membrane docking and disruption sites on phospholipase A2-like proteins revealed by complexation with the inhibitor suramin

Local myonecrosis resulting from snakebite envenomation is not efficiently neutralized by regular antivenom administration. This limitation is considered to be a significant health problem by the World Health Organization. Phospholipase A2-like (PLA2-like) proteins are among the most important proteins related to the muscle damage resulting from several snake venoms. However, despite their conserved tertiary structure compared with PLA2s, their biological mechanism remains incompletely understood. Different oligomeric conformations and binding sites have been identified or proposed, leading to contradictory data in the literature. In the last few years, a comprehensive hypothesis has been proposed based on fatty-acid binding, allosteric changes and the presence of two different interaction sites. In the present study, a combination of techniques were used to fully understand the structural-functional characteristics of the interaction between suramin and MjTX-II (a PLA2-like toxin). In vitro neuromuscular studies were performed to characterize the biological effects of the protein-ligand interaction and demonstrated that suramin neutralizes the myotoxic activity of MjTX-II. The high-resolution structure of the complex identified the toxin-ligand interaction sites. Calorimetric assays showed two different binding events between the protein and the inhibitor. It is demonstrated for the first time that the inhibitor binds to the surface of the toxin, obstructing the sites involved in membrane docking and disruption according to the proposed myotoxic mechanism. Furthermore, higher-order oligomeric formation by interaction with interfacial suramins was observed, which may also aid the inhibitory process. These results further substantiate the current myotoxic mechanism and shed light on the search for efficient inhibitors of the local myonecrosis phenomenon.Peer Reviewe

Filoviruses utilize glycosaminoglycans for their attachment to target cells

Filoviruses are the cause of severe hemorrhagic fever in human and nonhuman primates. The envelope glycoprotein (GP), responsible for both receptor binding and fusion of the virus envelope with the host cell membrane, has been demonstrated to interact with multiple molecules in order to enhance entry into host cells. Here we have demonstrated that filoviruses utilize glycosaminoglycans, and more specifically heparan sulfate proteoglycans, for their attachment to host cells. This interaction is mediated by GP and does not require the presence of the mucin domain. Both the degree of sulfation and the structure of the carbohydrate backbone play a role in the interaction with filovirus GPs. This new step of filovirus interaction with host cells can potentially be a new target for antiviral strategies. As such, we were able to inhibit filovirus GP-mediated infection using carrageenan, a broad-spectrum microbicide that mimics heparin, and also using the antiviral dendrimeric peptide SB105-A10, which interacts with heparan sulfate, antagonizing the binding of the virus to cells

Aquaporin-11 Contributes to TGF-β1-Induced Endoplasmic Reticulum Stress in Human Visceral Adipocytes: Role in Obesity-Associated Inflammation

Aquaporin-11 (AQP11) is expressed in human adipocytes, but its functional role remains unknown. Since AQP11 is an endoplasmic reticulum (ER)-resident protein that transports water, glycerol, and hydrogen peroxide (H2O2), we hypothesized that this superaquaporin is involved in ER stress induced by lipotoxicity and inflammation in human obesity. AQP11 expression was assessed in 67 paired visceral and subcutaneous adipose tissue samples obtained from patients with morbid obesity and normal-weight individuals. We found that obesity and obesity-associated type 2 diabetes increased (p < 0.05) AQP11 mRNA and protein in visceral adipose tissue, but not subcutaneous fat. Accordingly, AQP11 mRNA was upregulated (p < 0.05) during adipocyte differentiation and lipolysis, two biological processes altered in the obese state. Subcellular fractionation and confocal microscopy studies confirmed its presence in the ER plasma membrane of visceral adipocytes. Proinflammatory factors TNF-α, and particularly TGF-β1, downregulated (p < 0.05) AQP11 mRNA and protein expression and reinforced its subcellular distribution surrounding lipid droplets. Importantly, the AQP11 gene knockdown increased (p < 0.05) basal and TGF-β1-induced expression of the ER markers ATF4 and CHOP. Together, the downregulation of AQP11 aggravates TGF-β1-induced ER stress in visceral adipocytes. Owing to its "peroxiporin" properties, AQP11 overexpression in visceral fat might constitute a compensatory mechanism to alleviate ER stress in obesity