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Publications

2017

Development of a Mitochondriotropic Antioxidant Based on Caffeic Acid: Proof of Concept on Cellular and Mitochondrial Oxidative Stress Models

Authors
Teixeira, J; Cagide, F; Benfeito, S; Soares, P; Garrido, J; Baldeiras, I; Ribeiro, JA; Pereira, CM; Silva, AF; Andrade, PB; Oliveira, PJ; Borges, F;

Publication
JOURNAL OF MEDICINAL CHEMISTRY

Abstract
Targeting mitochondrial oxidative stress is an effective therapeutic strategy. In this context, a rational design of mitochondriotropic antioxidants (compounds 22-27) based on a dietary antioxidant (caffeic acid) was performed. Jointly named as AntiOxCINs, these molecules take advantage of the known ability of the triphenylphosphonium cation to target active molecules to mitochondria. The study was guided by structure-activity-toxicity-property relationships, and we demonstrate in this work that the novel AntiOxCINs act as mitochondriotropic antioxidants. In general, AntiOxCINs derivatives prevented lipid peroxidation and acted as inhibitors of the mitochondrial permeability transition pore. AntiOxCINs toxicity profile was found to be dependent on the structural modifications performed on the dietary antioxidant. On the basis of mitochondrial and cytotoxicity/antioxidant cellular data, compound 25 emerged as a potential candidate for the development of a drug candidate with therapeutic application in mitochondrial oxidative stress-related diseases. Compound 25 increased GSH intracellular levels and showed no toxicity on mitochondrial morphology and function.

2017

Dissimilar Symmetric Word Pairs in the Human Genome

Authors
Tavares, AH; Raymaekers, J; Rousseeuw, PJ; Silva, RM; Bastos, CAC; Pinho, AJ; Brito, P; Afreixo, V;

Publication
PACBB

Abstract
In this work we explore the dissimilarity between symmetric word pairs, by comparing the inter-word distance distribution of a word to that of its reversed complement. We propose a new measure of dissimilarity between such distributions. Since symmetric pairs with different patterns could point to evolutionary features, we search for the pairs with the most dissimilar behaviour. We focus our study on the complete human genome and its repeat-masked version.

2017

Message from general and program co-chairs

Authors
Cardoso, JMP; Huebner, M; Agosta, G; Silvano, C;

Publication
ACM International Conference Proceeding Series

Abstract

2017

SPR optimization using metamaterials in a D-type PCF refractive index sensor

Authors
Santos, DF; Guerreiro, A; Baptista, JM;

Publication
OPTICAL FIBER TECHNOLOGY

Abstract
Using the finite element method (FEM), this paper presents a numerical investigation of the performance analysis of a D-type photonic crystal fiber (D-type PCF) for refractive index sensing, based on surface plasmon resonance (SPR) with a planar structure made out of a metamaterial. COMSOL Multiphysics was used to evaluate the design of the referred refractive index optical fiber sensor, with higher accuracy and considerable economy of time and resources. A study of different metamaterials concentrations conformed by aluminum oxide (Al2O3) and silver (Ag) is carried out. Another structural parameters, which influences the refractive index sensor performance, the thickness of the metamaterial, is also investigated. The results indicate that the use of metamaterials provides a way of improving the performance of SPR sensors on optical fibers and allows to tailor the working parameters of the sensor.

2017

Multi-period flexibility forecast for low voltage prosumers

Authors
Pinto, R; Bessa, RJ; Matos, MA;

Publication
ENERGY

Abstract
Near-future electric distribution grids operation will have to rely on demand-side flexibility, both by implementation of demand response strategies and by taking advantage of the intelligent management of increasingly common small-scale energy storage. The Home energy management system (HEMS), installed at low voltage residential clients, will play a crucial role on the flexibility provision to both system operators and market players like aggregators. Modeling and forecasting multi-period flexibility from residential prosumers, such as battery storage and electric water heater, while complying with internal constraints (comfort levels, data privacy) and uncertainty is a complex task. This papers describes a computational method that is capable of efficiently learn and define the feasibility flexibility space from controllable resources connected to a HEMS. An Evolutionary Particle Swarm Optimization (EPSO) algorithm is adopted and reshaped to derive a set of feasible temporal trajectories for the residential net-load, considering storage, flexible appliances, and predefined costumer preferences, as well as load and photovoltaic (PV) forecast uncertainty. A support vector data description (SVDD) algorithm is used to build models capable of classifying feasible and non-feasible HEMS operating trajectories upon request from an optimization/control algorithm operated by a DSO or market player.

2017

Structure-guided mutagenesis reveals a hierarchical mechanism of Parkin activation

Authors
Tang, MY; Vranas, M; Krahn, AI; Pundlik, S; Trempe, JF; Fon, EA;

Publication
Nature Communications

Abstract
AbstractParkin and PINK1 function in a common pathway to clear damaged mitochondria. Parkin exists in an auto-inhibited conformation stabilized by multiple interdomain interactions. The binding of PINK1-generated phospho-ubiquitin and the phosphorylation of the ubiquitin-like (Ubl) domain of Parkin at Ser65 release its auto-inhibition, but how and when these events take place in cells remain to be defined. Here we show that mutations that we designed to activate Parkin by releasing the Repressor Element of Parkin (REP) domain, or by disrupting the interface between the RING0:RING2 domains, can completely rescue mutations in the Parkin Ubl that are defective in mitochondrial autophagy. Using a FRET reporter assay we show that Parkin undergoes a conformational change upon phosphorylation that can be mimicked by mutating Trp403 in the REP. We propose a hierarchical model whereby pUb binding on mitochondria enables Parkin phosphorylation, which, in turn, leads to REP removal, E3 ligase activation and mitophagy.

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