The effect of climate change on electricity planning

The literature is vast in what regards the relationship between climate change (CC) and energy, especially in the sense of pointing this sector as an inducer of greenhouse gases (GHG) and demonstrating the importance of Renewable Energy Sources (RES) in mitigating these impacts. The relationships in the opposite direction, i.e. the way how CC could affect energy systems, are now being recognized as increasingly important by some international organizations and authors. This is precisely the focus of this paper, aiming to demonstrate how CC can affect RES and future electricity scenarios. The work addresses the particular case of Portugal and departed from the assessment of the impact of CC upon parameters of interest to hydro, wind and solar power production, according to international studies. This information was used as input of an optimization model for a long term power planning, resulting in the proposal of trajectories of the Portuguese electricity system under different CC assumptions.This research was supported by a Marie Curie International Research Staff Exchange Scheme Fellowship within the 7th European Union Framework Programme, under project NETEP- European Brazilian Network on Energy Planning (PIRSES-GA-2013-612263

Synthesis and characterization of one-dimensional titanate structure

One-dimensional titania structures were synthesized trough a simple hydrothermal process in a highly alkaline conditions. The aim of this work was to elucidate the effect of time on the formation of 1D titanates as well on its structural characteristics (morphology, phase composition, surface area). Apart from that, the effect of heat treatment conditions on the stability of titanate based 1D samples has been investigated. The results have revealed that it is possible to form one-dimensional titanates already after 1 hour of hydrothermal synthesis. Although the composition of titanates is still under debate, the results probably correspond to the layered sodium titanates. The 1D prepared structures show a remarkable stability during heating, remaining the basic morphology and composition even up to 700°C

N,N-Diprotected dehydroamino acid derivatives: versatile substrates for the synthesis of novel amino acids

Non-proteinogenic amino acids are an important class of organic compounds that can have intrinsic biological activity or can be found in peptides with antiviral, antitumor, anti-inflammatory or immunosuppressive activities. This type of compounds is also important in drug development, in the elucidation of biochemical pathways and in conformational studies. Therefore, research towards efficient methods that allow the synthesis of these compounds constitutes an important area of peptide chemistry. In our laboratories we have developed a new and high yielding method for the synthesis of N,N-diprotected dehydroamino acid derivatives using tert-butyl pyrocarbonate and 4-dimethylaminopyridine. These compounds were used as substrates in several types of reactions, allowing the synthesis of a variety of new amino acid derivatives. Some of these new compounds are heterocyclic systems or contain heterocyclic moieties such as pyrazole, indole, or imidazole. Thus, several nitrogen heterocycles were reacted with N,N-diprotected dehydroalanine to give new beta-substituted alanines and dehydroalanines. Furanic amino acids were obtained treating the methyl ester of N-(4-toluenesulfonyl), N-(tert-butoxycarbonyl) dehydroalanine with carbon nucleophiles of the beta-dicarbonyl type having at least one methyl group attached to one of the carbonyl groups. Treatment of these furanic amino acids with trifluoracetic acid afforded pyrrole derivatives in good to high yields. A N,N-diprotected 1,4-dihydropyrazine was obtained reacting the methyl ester of N-(4-toluenesulfonyl), N-(tert-butoxycarbonyl)dehydroalanine with 4-dimethylaminopyridine and an excess of potassium carbonate. Tetrahydropyrazines were synthesized by reaction of this 1,4-dihydropyrazine derivative with nucleophiles or by electrochemical reduction. Cleavage of the N-protecting groups from the 1,4-dihydropyrazine gave a disubstituted pyrazine. This review covers the synthesis of N,N-diprotected dehydroamino acids and their application as precursors for the synthesis of newFEDER - Federación Española de Enfermedades Raras (POCI/QUI/59407/2004

Synthesis of new beta-amidodehydroaminobutyric acid derivatives and of new tyrosine derivatives using copper catalyzed C-N and C-O coupling reactions

Several beta-amidodehydroaminobutyric acid derivatives were prepared from N,C-diprotected beta-bromodehydroaminobutyric acids and amides by a copper catalyzed C-N coupling reaction. The best reaction conditions include the use of a catalytic amount of CuI, N,N’-dimethylethylenediamine as ligand and K2CO3 as base in toluene at 110 ºC. The stereochemistry of the products was determined using NOE difference experiments and the results obtained are in agreement with an E-stereochemistry. Thus, the stereochemistry is maintained in the case of the E-isomers of beta-bromodehydroaminobutyric acid dervatives, but when the Z-isomers were used as substrates the reaction proceeds with inversion of configuration. The use of beta-bromodehydrodipeptides as substrates was also tested. It was found that the reaction outcome depend on the stereochemistry of the beta-bromodehydrodipeptide and on the nature of the first amino acid residue. The products isolated were the beta-amidodehydrodipeptide derivatives and/or the corresponding dihydropyrazines. The same catalytic system (CuI/N,N’-dimethylethylene diamine) was used in the C-O coupling reactions between a tyrosine derivative and aryl bromides. The new O-aryltyrosine derivatives were isolated in moderate to good yields. The photophysical properties of two of these compounds were studied in four solvents of different polarity. The results show that these compounds after deprotection can used as fluorescence markers.This work was financed by FEDER through "Programa Operacional Factores de Competitividade"-COMPETE and by FCT-"Fundacao para a Ciencia e Tecnologia" through project "Projecto Estrategico-UI 686-2011-2012" Ref: PEst-C/QUI/UI0686/2011. The NMR spectrometer is part of the National NMR Network (RNRMN) and was purchased in the framework of the National Programme for Scientific Re-equipment, contract REDE/1517/RMN/2005, with funds from POCI 2010 (FEDER) and Fundacao para a Ciencia e a Tecnologia (FCT) and is supported with funds from FCT. G. P. acknowledges FCT for a PhD grant SFRH/BD/38766/2007. H. V. acknowledges FCT for a PhD grant SFRH/BD/7265/2010

The role of Polypharmacology and Cholinesterase inhibitors

Publisher Copyright: © 2023 NOVA School of Science and Technology. ChemistrySelect published by Wiley-VCH GmbH.Alzheimer's disease (AD) is a devastating syndrome that accounts for 60–70 % of all dementia cases, putting an enormous burden on global healthcare and economy. Unfortunately, there is no cure for AD, and the currently approved drugs are limited in their effects. Given the various pathological mechanisms behind AD, the “one-target, one-drug” paradigm for drug design became obsolete, and a new paradigm, polypharmacology, emerged. Consequently, a greater focus has been put towards multi-target directed ligands (MTDLs), as these can regulate several targets operating in the disease network. Parallel to that, cholinesterase inhibitors have regained popularity after decades of being considered only symptomatic agents with no disease-modifying properties. In this review, the current AD hypotheses and therapeutic targets, the concept of polypharmacology in AD pathology and the importance of cholinesterases in the pathogenesis and biochemical processes of AD are discussed, with a final overview of the current development in cholinesterase-based MTDLs.publishersversionpublishe

Antioxidant activity of honey samples from Trás-os-Montes and inhibitory effect of hydrogen peroxide on pathogenic yeast growth

Honey has been used since ancient times in the treatment of respiratory infections and to heal wounds. These effects are related to its physical and chemical properties. The major antibacterial factor in honey is hydrogen peroxide, which is produced by glucose oxidase originating from hypopharyngeal glands of honey bees, and by catalase, which a originates from polle

Cooperação orientada à produção de conhecimento científico

O termo e conceito cooperação tem vindo a ocupar cada vez mais e com maior ênfase os espaços noticiosos e de debate, sustentando a rede de projectos que se sucedem um pouco por todo o planeta, com fim à construção de uma “casa comum” onde, como nas grandes famílias, as aprendizagens matriciais passam pelo “aprender a viver juntos”, “aprender a aprender juntos” e “aprender a crescer juntos”, princípios de globalização planetária

Synthesis and reactivity of a 1,4-dihydropyrazine derivative

N,N-Bis-(tert-butoxycarbonyl)-2,5-bis-methoxycarbonyl-1,4-dihydropyrazine can be obtained in high yield by treatment of the methyl ester of N-(4-toluenesulfonyl)-N-(tert-butoxycarbonyl)-alpha,beta-didehydroalanine with dimethylaminopyridine and potassium carbonate. This compound was used as substrate in Michael addition reactions with several types of nucleophiles. The electrochemical behaviour of this pyrazine derivative was also studied by cyclic voltammetry and by controlled potential electrolysis.We wish to thank the Fundação para a Ciência e a Tecnologia for financial support (project no. POCTI/1999/QUI/32689)

Individual variation in Plasmodium vivax malaria risk - Are repeatedly infected people just unlucky?

Copyright: © 2023 Corder et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Extensive research has examined why some people have frequent Plasmodium falciparum malaria episodes in sub-Saharan Africa while others remain free of disease most of the time. In contrast, malaria risk heterogeneity remains little studied in regions where P. vivax is the dominant species. Are repeatedly infected people in vivax malaria settings such as the Amazon just unlucky? Here, we briefly review evidence that human genetic polymorphism and acquired immunity after repeated exposure to parasites can modulate the risk of P. vivax infection and disease in predictable ways. One-fifth of the hosts account for 80% or more of the community-wide vivax malaria burden and contribute disproportionally to onward transmission, representing a priority target of more intensive interventions to achieve malaria elimination. Importantly, high-risk individuals eventually develop clinical immunity, even in areas with very low or residual malaria transmission, and may constitute a large but silent parasite reservoir.publishersversionpublishe