Activated carbon from Water Hyacinth as electrocatalyst for oxygen reduction reaction in an alkaline fuel cell

Water Hyacinth is an invasive aquatic plant with an excellent carbon source with heteroatoms. Activated carbon is a viable choice as an electrocatalyst for fuel cell applications. Based on the plant's leaves, stem, and root, we got activated carbons using KOH at 730 °C with N₂. The samples, named WH_LA730, WH _SA730, and WH_RA730, were examined as electrocatalysts for oxygen reduction reaction in 0.5 M KOH. The high surface area and nitrogen content in the activated carbon provided a good electrochemical activity. The potential reaction for WH_SA730 was at 0.9 V and 0.85 V for WH_RA730. Both samples showed a promising activated carbon for the alkaline fuel cell compared to WH_LA730.     

Extrusion of polypropylene/chitosan/poly(lactic-acid) films: Chemical,mechanical, and thermal properties

Development of extruded films composed of biopolymers blended with synthetic polymers aims to minimize the environmental impact of plastic waste-materials and lead to the sustainable plastic industry. To produce biodegradable polymeric blends, the weight content of biopolymers must be maximum without compromising the performance properties of the extruded films. Using a solvent-free extrusion method, films composed of polypropylene, poly(lactic-acid), and Chitosan, can be obtained with the use of polypropylene-graft-maleic anhydride and glycerol as compatibilizer and plasticizer, respectively. Extruded films with up to a 50 wt% content of biopolymers show acceptable thermal and mechanical properties, where the use of compatibilizer improves the processing characteristics and homogeneous distribution of chitosan throughout the films. Therefore, the extruded films can be considered as alternatives to conventional synthetic-polymer films, due to their acceptable mechanical and thermal properties with direct potential applications in extrusion-method mass production of biodegradable polymers.     

Kinetics of the glass transition of styrene-butadiene-rubber: Dielectric spectroscopy and fast differential scanning calorimetry

The glass transition is relevant for performance definition in rubber products. For extrapolation to high-frequency behavior, time–temperature superposition is usually assumed, although most complex rubber compounds might be outside of its area of validity. Fast differential scanning calorimetry (FDSC) with cooling rates up to 1500 K/s and broadband dielectric spectroscopy (BDS) with frequencies up to 20 MHz are applied here to directly access both kinetics and dynamics of glass formation in a wide frequency range. For the first-time, the relation between the thermal vitrification and the dielectric relaxation is studied on vulcanized styrene-butadiene rubber, showing that both cooling rate and frequency dependence of its glass transition can be described by one single Vogel-Fulcher-Tammann-Hesse equation. The results indicate the validity of the Frenkel-Kobeko-Reiner equation. Another focus is the sample preparation of vulcanized elastomers for FDSC and BDS as well as the temperature calibration below 0°C.     

Hyalectanase Activities by the ADAMTS Metalloproteases

The hyalectan family is composed of the proteoglycans aggrecan, versican, brevican and neurocan. Hyalectans, also known as lecticans, are components of the extracellular matrix of different tissues and play essential roles in key biological processes including skeletal development, and they are related to the correct maintenance of the vascular and central nervous system. For instance, hyalectans participate in the organization of structures such as perineural nets and in the regulation of neurite outgrowth or brain recovery following a traumatic injury. The ADAMTS (A Disintegrin and Metalloprotease domains, with thrombospondin motifs) family consists of 19 secreted metalloproteases. These enzymes also perform important roles in the structural organization and function of the extracellular matrix through interactions with other matrix components or as a consequence of their catalytic activity. In this regard, some of their preferred substrates are the hyalectans. In fact, ADAMTSs cleave hyalectans not only as a mechanism for clearance or turnover of proteoglycans but also to generate bioactive fragments which display specific functions. In this article we review some of the physiological and pathological effects derived from cleavages of hyalectans mediated by ADAMTSs.     

Welfare benefits in highly decentralized fiscal systems: Evidence on interregional mimicking

This paper analyses the determinants of welfare benefit levels within a highly fiscally decentralized context. More specifically, we analyse the role of mimicking as a driver of the institutional design of subnational government policies in the absence of federal co-ordination and financing. Empirically, we focus on the welfare benefit programmes of Spanish regional governments during the period 1996–2015. Our results strongly support the significant role played by mimicking: regional public agents observe what their peers are doing and act accordingly, and this holds even in a context of low mobility of households.     

A general formulation for the contact between superellipsoid surfaces and nodal points

Multibody System Dynamics - The superellipsoids, part of the family of superquadratics, have geometric and mathematical properties that not only make them suitable for the representation of solids,...     

Effect of simulated acidic and salty fermentation conditions on kinetic growth parameters and probiotic potential of Lactobacillus acidipiscis and Lactobacillus pentosus

The technological stress during food processing may alter the beneficial interactions of food-associated Lactobacillus on the host. The effect of initial combined acidic (pH 5.0) and osmotic stress (NaCl 5 %, w/v with or without CaCl₂ 0.02 %, w/v) typically present in vegetable fermentations and cheesemaking were investigated. The growth kinetics prediction, hydrophobicity, auto-aggregation, in vitro survival and adhesion were determined in Lactobacillus acidipiscis and Lactobacillus pentosus isolated from a Mexican salty cheese. The growth was modelled with the modified Gompertz equation (R > 0.99; RMSE < 0.01). The lag phase increased (>10 h), and auto-aggregation was reduced. Hydrophobicity and S-layer total proteins varied. Gut survival reduced >4 log 10 units compared to the initial intake. Nevertheless, adhesion remained the same. Hence, combined stress affected the technological and physiological properties of both strains negatively. Further research is needed to identify the effect of the combined stress on the potential bioactivity of the strains.