Self-identification algorithm for zeolite-based thermal capacity gas sensor

Microsystem Technologies - We demonstrate a new operation mode of thermal gas sensor based on thermal capacity extraction with identification algorithm. The system is a silicon microstructure...     

A memetic algorithm for the multi-compartment vehicle routing problem with stochastic demands

The multi-compartment vehicle routing problem (MC-VRP) consists of designing transportation routes to satisfy the demands of a set of customers for several products that, because of incompatibility constraints, must be loaded in independent vehicle compartments. Despite its wide practical applicability the MC-VRP has not received much attention in the literature, and the few existing methods assume perfect knowledge of the customer demands, regardless of their stochastic nature. This paper extends the MC-VRP by introducing uncertainty on what it is known as the MC-VRP with stochastic demands (MC-VRPSD). The MC-VRPSD is modeled as a stochastic program with recourse and solved by means of a memetic algorithm. The proposed memetic algorithm couples genetic operators and local search procedures proven to be effective on deterministic routing problems with a novel individual evaluation and reparation strategy that accounts for the stochastic nature of the problem. The algorithm was tested on instances of up to 484 customers, and its results were compared to those obtained by a savings-based heuristic and a memetic algorithm (MA/SCS) for the MC-VRP that uses a spare capacity strategy to handle demand fluctuations. In addition to effectively solve the MC-VRPSD, the proposed MA/SCS also improved 14 best known solutions in a 40-problem testbed for the MC-VRP.     

Experimental tracking of silica dispersion into silicone polymer

This work deals with the experimental tracking of a dispersion of very fine silica particles in PDMS using a new, easily implemented methodology. The dispersion experiments are carried out in an 8-l capacity mixer equipped with a torquemeter. Using a Couette analogy, the torque-rotational speed data can be converted into process viscosity-effective shear rate data. Simultaneously, the Particle Size Distribution (PSD) evolution is followed through Laser Light Scattering measurements on diluted samples. The PSD evolution allowed us to interpret the dispersion process in terms of different mechanisms, such as breaking-up and erosion of aggregates, as well as, in some cases, re-agglomeration (or flocculation) of particles.     

Mice Lacking Gpr179 with Complete Congenital Stationary Night Blindness Are a Good Model for Myopia

Mutations in GPR179 are one of the most common causes of autosomal recessive complete congenital stationary night blindness (cCSNB). This retinal disease is characterized in patients by impaired dim and night vision, associated with other ocular symptoms, including high myopia. cCSNB is caused by a complete loss of signal transmission from photoreceptors to ON-bipolar cells. In this study, we hypothesized that the lack of Gpr179 and the subsequent impaired ON-pathway could lead to myopic features in a mouse model of cCSNB. Using ultra performance liquid chromatography, we show that adult Gpr179^−/− mice have a significant decrease in both retinal dopamine and 3,4-dihydroxyphenylacetic acid, compared to Gpr179^+/+ mice. This alteration of the dopaminergic system is thought to be correlated with an increased susceptibility to lens-induced myopia but does not affect the natural refractive development. Altogether, our data added a novel myopia model, which could be used to identify therapeutic interventions.     

A multifactor study of catalyzed hydrolysis of solid NaBH4 on cobalt nanoparticles: Thermodynamics and kinetics

In the present work, hydrogen generation through hydrolysis of a NaBH_4(s)/catalyst_(s) solid mixture was realized for the first time as a solid/liquid compact hydrogen storage system using Co nanoparticles as a model catalyst. The performance of the system was analysed from both the thermodynamic and kinetic points of view and compared with the classical catalyzed hydrolysis of a NaBH₄ solution. The kinetic analysis of the NaBH_4(s)/catalyst_(s)/H₂O_(l) system shows that the reaction is first order with respect to the catalyst concentration, and the activation energy equal to 35 kJ mol_NaBH4⁻¹. Additionally, calorimetric measurements of the heat evolved during the hydrolysis of NaBH₄ solutions evidence the global process energy (−217 kJ mol_NaBH4⁻¹). Characterization of the cobalt nanoparticles before and after the hydrolysis associated with the calorimetric measurements suggests the “in situ” formation of a catalytically active Co_xB phase through “reduction” of an outer protective oxide layer that is regenerated at the end of reaction.     

N‐Arylsulfonyl Indolines as Retinoic Acid Receptor‐Related Orphan Receptor γ (RORγ) Agonists

The nuclear retinoic acid receptor‐related orphan receptor γ (RORγ; NR1F3) is a key regulator of inflammatory gene programs involved in T helper 17 (T_H17) cell proliferation. As such, synthetic small‐molecule repressors (inverse agonists) targeting RORγ have been extensively studied for their potential as therapeutic agents for various autoimmune diseases. Alternatively, enhancing T_H17 cell proliferation through activation (agonism) of RORγ may boost an immune response, thereby offering a potentially new approach in cancer immunotherapy. Herein we describe the development of N‐arylsulfonyl indolines as RORγ agonists. Structure–activity studies reveal a critical linker region in these molecules as the major determinant for agonism. Hydrogen/deuterium exchange coupled to mass spectrometry (HDX‐MS) analysis of RORγ–ligand complexes help rationalize the observed results.     

Random poly(ε‐caprolactone‐L‐alanine) by direct melt copolymerization

A series of random polyesteramides (PEAs) with a range of molar composition from 90/10 to 50/50 were synthesized by direct melt polycondensation of ε‐caprolactone and l ‐alanine. Their structure was fully characterized by Fourier transform IR and NMR spectroscopy. The resulting copolymers are completely amorphous with the exception of PEA‐90/10 which possesses a semicrystalline structure. These PEAs present increasing glass transition temperatures at increasing l ‐alanine contents and exhibit fairly good thermal stability with 10% mass loss temperatures reaching 315 °C. © 2020 Society of Industrial Chemistry     

Copper(I/II), α/β‐Synuclein and Amyloid‐β: Menage à Trois?

Copper binding to α‐synuclein (aS) and to amyloid‐β (Ab) has been connected to Parkinson's and Alzheimer's disease (AD), respectively, because Cu ions can modulate the peptide aggregation, and these Cu ? peptide complexes can catalyse the production of reactive oxygen species (ROS). In a significant proportion of AD brains, aggregation of aS and Ab has been detected, and it was proposed that Ab and aS interact with each other. Thus, we investigated the potential interactions of Ab and aS through their binding of copper(I) and copper(II). Additionally, β‐synuclein (bS) was investigated, due to its additional methionine residue, a potential Cu^I ligand. We found that: 1) the peptides containing the Cu‐binding domains Ab1–16, aS1–15 and bS1–15 have similar affinities towards Cu^II and towards Cu^I, with Ab1–16 being slightly stronger, 2) in the case of Cu^I, the additional Met residue in bS1–15 increased the affinity slightly, 3) the exchange of Cu^I/II between the two peptides is rapid (≤ms), 4) a/bS1–15 and Ab1–16 form a heterodimeric complex with Cu^II, 5) Cu^I probably promotes a transient ternary complex, 6) the different Cu^I/II coordination of Ab1–16, aS1–15 and bS1–15 impacts the capacity to produce ROS and to oxidise catechol, and 7) when Ab1–16, aS1–15 and Cu are present, the ROS production more closely resembles that by Ab1–16. The work gives insights into the coordination chemistry of these related peptides, and the relevance of coordination differences, the ternary complex and ROS production are discussed.     

Inhibition of polyphenoloxidase from apple by Maillard reaction products prepared from glucose or fructose with l-cysteine under various conditions of pH and temperature

The effects of Maillard reaction products (MRPs), synthesized from equimolar glucose or fructose with l-cysteine (1 mol l⁻¹) aqueous model mixtures, by modulating pH and temperature of heating, according to a two-factor and five-level experimental design, were investigated on polyphenoloxidase (PPO) activity from apple. Final pH and absorbance measurements at 350 nm were also selected as indicators of the Maillard reaction development and checked. In general, inhibitory potency (IP) of the mixtures increased with the increase in temperature (80-120°C) and the decrease in pH (pH 2.0-12.0) of the reaction medium. A linear relationship between the IP and heating time (0-48 h) or Abs.350 nm (0-70 AU) was demonstrated for glucose/cysteine system heated from 80°C to 120°C. Polarographic and spectrophotometric data were used to calculate kinetic constants and activation energy (Ea) values of inhibitory MRPs formation versus PPO activity and of those compounds absorbing at 350 nm. Ea values for these reactions were close, being 191 and 124 kJ mol⁻¹, respectively. The experimental design allowed to conclude that linear effects of both factors as well as a quadratic effect of pH were significant, leading to optimum conditions for the production of glucose-derived MRPs inhibitors. In most cases, glucose produced MRPs with higher IP compared to counterpart fructose-cysteine MRPs.     

Infiltration and Top Seed Growth-Textured YBCO Bulks With Multiple Holes

The recently reported hole-patterned YBa₂Cu₃O _y (Y123) bulks with improved superconducting properties are highly interesting from material quality and application variety points of view. It is well known that the core of plain bulk superconductors needs to be fully oxygenated and some defects like cracks, pores, and voids must be suppressed in order that the material can trap a high magnetic field or carry a high current density. To minimize the above defects, we have used a combination of standard superconducting ceramic processing and an infiltration technique to prepare regularly perforated YBa₂Cu₃O _y (Y123) bulk superconductors. This process leads to negligible shrinkage upon annealing and a uniform distribution of Y211 inclusions. Texture was evidenced by neutron pole figure measurements. Flux mapping was used to verify the superconducting homogeneity of the samples and to investigate the field-trapping ability. In addition, the textured drilled samples were reinforced using resin or metal impregnation and the influence of the different processing steps on the hardness of the materials has been investigated.