Enzymatic phosphorylation of hair keratin enhances fast adsorption of cationic moieties

The current study describes the in vitro phosphorylation of a human hair keratin, using protein kinase for the first time. Phosphorylation of keratin was demonstrated by 31P NMR (Nuclear Magnetic Resonance) and Diffuse Reflectance Infrared Fourier Transform (DRIFT) techniques. Phosphorylation induced a 2.5 fold increase of adsorption capacity in the first 10 minutes for cationic moiety like Methylene Blue (MB). Thorough description of MB adsorption process was performed by several isothermal models. Reconstructed fluorescent microscopy images depict distinct amounts of dye bound to the differently treated hair. The results of this work suggest that the enzymatic phosphorylation of keratins might have significant implications in hair shampooing and conditioning, where short application times of cationic components are of prime importance.

Gold nanoparticles functionalised with fast water exchanging Gd3+ chelates: Linker effects on the relaxivity

The relaxivity displayed by Gd3+ chelates immobilized onto gold nanoparticles is the result of complex interplay between nanoparticle size, water exchange rate and chelate structure. In this work we study the effect of the length of -thioalkyl linkers, anchoring fast water exchanging Gd3+ chelates onto gold nanoparticles, on the relaxivity of the immobilized chelates. Gold nanoparticles functionalized with Gd3+ chelates of mercaptoundecanoyl and lipoyl amide conjugates of the DO3A-N-(-amino)propionate chelator were prepared and studied as potential CA for MRI. High relaxivities per chelate, of the order of magnitude 28-38 mM-1s-1 (30 MHz, 25 ºC) were attained thanks to simultaneous optimization of the rotational correlation time and of the water exchange rate. Fast local rotational motions of the immobilized chelates around connecting linkers (internal flexibility) still limit the attainable relaxivity. The degree of internal flexibility of the immobilized chelates seems not to be correlated with the length of the connecting linkers. Biodistribution and MRI studies in mice suggest that the in vivo behavior of the gold nanoparticles is determined mainly by size. Small nanoparticles (HD= 3.9 nm) undergo fast renal clearance and avoidance of the RES organs while larger nanoparticles (HD= 4.8 nm) undergo predominantly hepatobiliary excretion. High relaxivities, allied to chelate and nanoparticle stability and fast renal clearance in vivo suggests that functionalized gold nanoparticles hold great potential for further investigation as MRI Contrast Agents. This study contributes to understand the effect of linker length on the relaxivity of gold nanoparticles functionalized with Gd3+ complexes. It is a relevant contribution towards “design rules” for nanostructures functionalized with Gd3+ chelates as Contrast Agents for MRI and multimodal imaging.

Desenvolvimento de microcápsulas ativadas por radiação solar para aplicação em painéis cerâmicos exteriores

Dissertação de mestrado integrado em Engenharia de Materiais

Carbon materials as new generation of new electron shuttles for the anaerobic degradation of environmental xenobiotics

Tese de Doutoramento em Engenharia Química e Biológica

Nanotechnological approaches using curcumin and Withania somnifera: neuroprotection and antimicrobial activities

Tese de Doutoramento em Biologia de Plantas

Highly robust hydrogels via a fast, simple and cytocompatible dual crosslinking-based process

A highly robust hydrogel device made from a single biopolymer formulation is reported. Owing to the presence of covalent and non-covalent crosslinks, these engineered systems were able to (i) sustain a compressive strength of ca. 20 MPa, (ii) quickly recover upon unloading, and (iii) encapsulate cells with high viability rates.

Highly robust chitosan hydrogels via a fast, simple and biocompatible dual crosslinking-based process

Load-bearing soft tissues such as cartilage, blood vessels and muscles are able to withstand a remarkable compressive stress of several MPa without fracturing. Interestingly, most of these structural tissues are mainly composed of water and in this regard, hydrogels, as highly hydrated 3D-crosslinked polymeric networks, constitute a promising class of materials to repair lesions on these tissues. Although several approaches can be employed to shape the mechanical properties of artificial hydrogels to mimic the ones found on biotissues, critical issues regarding, for instance, their biocompatibility and recoverability after loading are often neglected. Therefore, an innovative hydrogel device made only of chitosan (CHI) was developed for the repair of robust biological tissues. These systems were fabricated through a dual-crosslinking process, comprising a photo- and an ionic-crosslinking step. The obtained CHIbased hydrogels exhibited an outstanding compressive strength of ca. 20 MPa at 95% of strain, which is several orders of magnitude higher than those of the individual components and close to the ones found in native soft tissues. Additionally, both crosslinking processes occur rapidly and under physiological conditions, enabling cellsâ encapsulation as confirmed by high cell survival rates (ca. 80%). Furthermore, in contrast with conventional hydrogels, these networks quickly recover upon unloading and are able to keep their mechanical properties under physiological conditions as result of their non-swell nature.

Sensitive label-free electron chemical capacitive transducer signal for D-dimer electroanalyses

Supplementary data associated with this article can be found, in the online version, at: http://dx.doi.org/10.1016/j.electacta.2015.09.169.

Effect of different carbon materials as electron shuttles in the anaerobic biotransformation of nitroanilines

Aromatic amines resulted from azo dyes biotransformation under anaerobic conditions are generally recalcitrant to further anaerobic degradation. The catalytic effect of carbon materials (CM) on the reduction of azo dyes is known and has been confirmed in this work by increasing 3-fold the biological reduction rate of Mordant Yellow 1 (MY1). The resulting m-nitroaniline (m-NoA) was further degraded to m-phenylenediamine (m-Phe) only in the presence of CM. The use of CM to degraded anaerobically aromatic amines resulted from azo dye reduction was never reported before. In the sequence, we studied the effect of different CM on the bioreduction of o-, m- and p-NoA. Three microporous activated carbons with different surface chemistry, original (AC0), chemical oxidized with HNO3 (ACHNO3) and thermal treated (ACH2), and three mesoporous carbons, xerogels (CXA and CXB) and nanotubes (CNT) were assessed. In the absence of CM, NoA were only partially reduced to the corresponding Phe, whereas in the presence of CM, more than 90% was converted to the corresponding Phe. ACH2 and AC0 were the best electron shuttles, increasing the rates up to 8-fold. In 24h, the biological treatment of NoA and MY1 with AC0, decreased up to 88% the toxicity towards a methanogenic consortium, as compared to the non-treated solutions. This article is protected by copyright. All rights reserved

Production of whey protein-based aggregates under ohmic heating

Formation of whey protein isolate protein aggregates under the influence of moderate electric fields upon ohmic heating (OH) has been monitored through evaluation of molecular protein unfolding, loss of its solubility, and aggregation. To shed more light on the microstructure of the protein aggregates produced by OH, samples were assayed by transmission electron microscopy (TEM). Results show that during early steps of an OH thermal treatment, aggregation of whey proteins can be reduced with a concomitant reduction of the heating chargeby reducing the come-up time (CUT) needed to reach a target temperatureand increase of the electric field applied (from 6 to 12 V cm1). Exposure of reactive free thiol groups involved in molecular unfolding of -lactoglobulin (-lg) can be reduced from 10 to 20 %, when a CUT of 10 s is combined with an electric field of 12 V cm1. Kinetic and multivariate analysis evidenced that the presence of an electric field during heating contributes to a change in the amplitude of aggregation, as well as in the shape of the produced aggregates. TEM discloses the appearance of small fibrillar aggregates upon the influence of OH, which have recognized potential in the functionalization of food protein networks. This study demonstrated that OH technology can be used to tailor denaturation and aggregation behavior of whey proteins due to the presence of a constant electric field together with the ability to provide a very fast heating, thus overcoming heat transfer limitations that naturally occur during conventional thermal treatments.

The Word Brain - A Short Guide to Fast Language Learning

How long does it take to learn another language? How many words do you need to learn? Are languages within the reach of everybody? Which teachers would you choose and which teachers should you avoid? These are some of the questions you ask yourself when you start learning a new language.The Word Brain provides the answers. If you have learned foreign languages in the past, consider reading it. If you or your children need to learn languages in the future, you must read it. What you will discover in two hours will change for ever the way you see languages and language learning. The principles of The Word Brain are timeless. Our children’s grandchildren will follow them when they discover the people of our planet.

Neural mechanisms for fast recognition of auditory emotion

Emotion, audition, event-related potentials, MMN, multidimensional scaling, timbre, perception

Electron Beam Welding In-Process Control and Monitoring

This work presents the results of an investigation of processes in the melting zone during Electron Beam Welding(EBW) through analysis of the secondary current in the plasma.The studies show that the spectrum of the secondary emission signal during steel welding has a pronounced periodic component at a frequency of around 15–25 kHz. The signal contains quasi-periodic sharp peaks (impulses). These impulses have stochastically varying amplitude and follow each other inseries, at random intervals between series. The impulses have a considerable current (up to 0.5 A). It was established that during electron-beam welding with the focal spot scanning these impulses follow each other almost periodically. It was shown that the probability of occurrence of these high-frequency perturbation increases with the concentration of energy in the interaction zone. The paper also presents hypotheses for the mechanism of the formation of the high-frequency oscillations in the secondary current signal in the plasma.

Fast and furious: a look at the death of animals on the highway MS-080, Southwestern Brazil

Several factors, such as hunting and the pet trade, are responsible for the worldwide decline of wildlife populations. In addition, fatal collisions with vehicles on highways have also taken one of the largest tolls. This study aimed to quantify the richness and abundance of vertebrate roadkill along highway MS-080 in Mato Grosso do Sul, Central-West Brazil. We compare the amount of roadkill to the distance between cities, moon phases and the flow of vehicles on the highway. Samples were collected weekly between March and September 2011, totaling 257 individuals, belonging to 32 families and 52 species, resulting in an index of 0.13 individuals hit/km. Birds were the most frequently hit taxa, followed by mammals. The most affected species was Cariama cristata (Cariamidae), followed by Cerdocyon thous (Canidae). The sections of highway closest to cities had the highest number of individual animals killed. Our observations indicate that the density of the vegetation next to the highway positively influences the amount of roadkill.