Development of chitosan packaging films with carvacrol and grape seed extract as antimicrobial and antioxidant agents

In order to produce packaging films with a broad spectrum of action on microorganisms, the effect of two antimicrobial (AM) to be included in the films, carvacrol and GSE were studied separately on different microorganisms. Carvacrol was more effective against the grampositive bacteria than against the gram-negative bacterium. GSE was not effective against yeast. Subsequently, a search for optimal combinations of carvacrol, GSE and the addition of chitosan (as a third component with film forming properties) was carried out. Response surface analysis showed several synergetic effects and three optimal AM combinations (OAMC) were obtained for each microorganism. The experimental validation confirmed that the optimal solutions found can successfully predict the response for each microorganism. The optimization of mixtures of the three components, but this time, using the same concentration for all microorganisms, was also studied to obtain an OAMC with wide spectrum of activity. The results of the response surface analysis showed several synergistic effects for all microorganisms. Three OAMC, OAMC-1, OAMC-2, OAMC-3, were found to be the optimal mixtures for all microorganisms. The radical scavenging activity (RSA) of the different agents was then compared with a standard antioxidant (AOX) BHT, at different concentrations; as also at the OAMC. The RSA increased in the following order: chitosan

Squaric acid/4-aminoquinoline conjugates: novel potent antiplasmodial agents

We report the synthesis and structure–activity relationship (SAR) analysis of a series of hybrid compounds containing a squaric moiety conjugated with heterocyclic moieties from well-known antimalarials. This novel series of compounds presents improved antiplasmodial activity compared with the squaric derivatives described in our previous work. Three compounds, 8b (IC50 = 99 nM), 8c (IC50 = 95 nM), and 8d (IC50 = 105 nM) had greater in vitro potency than chloroquine 1 (IC50 = 140 nM) against chloroquine resistant Plasmodium falciparum. In addition, they were noncytotoxic against NIH 3T3 and Hek 293T cells.

Synthesis and computer-assisted design of mitochondrial electron transport-chain inhibitors as antimalarial agents

Tese de doutoramento, Farmácia (Química Farmacêutica e Terapêutica), Universidade de Lisboa, Faculdade de Farmácia, 2014

Using genomics for drug discovery in medulloblastoma

Tese de doutoramento, Medicina (Neurocirurgia), Universidade de Lisboa, Faculdade de Medicina, 2014

Partial volume correction using bimodal contrast agents in PET-MRI

Tese de mestrado integrado em Engenharia Biomédica e Biofísica, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2014

Essential oils as anti-nematode agents and their influence on in vitro nematode

Tese de doutoramento, Biologia (Biotecnologia), Universidade de Lisboa, Faculdade de Ciências, 2015

'It's Almost Like Talking to a Person': Student Discolsure to Pedagogical Agents in Sensitive Setting

Online chatbots (also known as pedagogical agents or virtual assistants) are becoming embedded into the fabric of technology, both in educational and commercial settings. Yet understanding of these technologies is inchoate and often untheorised, influenced by individuals’ willingness to trust technologies, aesthetic appearance of the chatbot and technical literacy, among other factors. This paper draws upon data from two research studies that evaluated students’ experiences of using pedagogical agents in education using responsive evaluation. The findings suggest that emotional connections with pedagogical agents were intrinsic to the user’s sense of trust and therefore likely to affect levels of truthfulness and engagement. They also indicate that the topic of the pedagogical agent-student interaction is key to the student’s experience. The implications of these studies are that truthfulness, personalisation and emotional engagement are all vital components in using pedagogical agents to enhance online learning.

Beyond Robotic Wastelands of Time: Abandoned Pedagogical Agents and New Pedalled Pedagogies

Chatbots, known as pedagogical agents in educational settings, have a long history of use, beginning with Alan Turing’s work. Since then online chatbots have become embedded into the fabric of technology. Yet understandings of these technologies are inchoate and often untheorised. Integration of chatbots into educational settings over the past five years suggests an increase in interest in the ways in which chatbots might be adopted and adapted for teaching and learning. This article draws on historical literature and theories that to date have largely been ignored in order to (re)contextualise two studies that used responsive evaluation to examine the use of pedagogical agents in education. Findings suggest that emotional interactions with pedagogical agents are intrinsic to a user’s sense of trust, and that truthfulness, personalisation and emotional engagement are vital when using pedagogical agents to enhance online learning. Such findings need to be considered in the light of ways in which notions of learning are being redefined in the academy and the extent to which new literacies and new technologies are being pedalled as pedagogies in ways that undermine what higher education is, is for, and what learning means.

Understanding citizen media as practice: agents, processes, publics

Much recent commentary on citizen media has focused on online platforms as means through which citizens may disseminate self-produced media content that challenges dominant discourses or makes visible hidden realities. This chapter goes beyond a concern with media content to explore the much broader range of socially situated practices that develop around citizen media. Drawing on Couldry’s proposal for a practice paradigm in media research, it suggests shifting the focus from ‘citizen media’ to ‘citizen media practices’ and demonstrates, through a case study of communication activism in the World Social Forum, how this framework can bring into view a broad range of citizen media practices (beyond those directly concerned with the production and circulation of media content), the different forms of agency that such practices make possible, and the social fabric they can help generate. I conclude by arguing that a practice framework necessitates a rethink of the way that the concept of (counter-) publics is used in the context of citizen media. Citizen media practices of the kind described here can be understood not only as practices of ‘making public’ previously unreported issues and perspectives, but as practices of public¬-making: practices that support the formation of publics.

MASCEM: electricity markets simulation with strategic agents

Electricity markets are complex environments, involving numerous entities trying to obtain the best advantages and profits while limited by power-network characteristics and constraints.1 The restructuring and consequent deregulation of electricity markets introduced a new economic dimension to the power industry. Some observers have criticized the restructuring process, however, because it has failed to improve market efficiency and has complicated the assurance of reliability and fairness of operations. To study and understand this type of market, we developed the Multiagent Simulator of Competitive Electricity Markets (MASCEM) platform based on multiagent simulation. The MASCEM multiagent model includes players with strategies for bid definition, acting in forward, day-ahead, and balancing markets and considering both simple and complex bids. Our goal with MASCEM was to simulate as many market models and player types as possible. This approach makes MASCEM both a short- and mediumterm simulation as well as a tool to support long-term decisions, such as those taken by regulators. This article proposes a new methodology integrated in MASCEM for bid definition in electricity markets. This methodology uses reinforcement learning algorithms to let players perceive changes in the environment, thus helping them react to the dynamic environment and adapt their bids accordingly.

Seller, buyer and VPP agents behavior on a simulated electricity market

Competitive electricity markets are complex environments, involving a large number of different entities, playing in a dynamic scene to obtain the best advantages and profits. MASCEM is an electricity market simulator able to model market players and simulate their operation in the market. As market players are complex entities, having their characteristics and objectives, making their decisions and interacting with other players, a multi-agent architecture is used and proved to be adequate. MASCEM players have learning capabilities and different risk preferences. They are able to refine their strategies according to their past experience (both real and simulated) and considering other agents’ behavior. Agents’ behavior is also subject to its risk preferences.

MV producers and consumers agents characterization with DSM techniques

This paper consist in the establishment of a Virtual Producer/Consumer Agent (VPCA) in order to optimize the integrated management of distributed energy resources and to improve and control Demand Side Management DSM) and its aggregated loads. The paper presents the VPCA architecture and the proposed function-based organization to be used in order to coordinate the several generation technologies, the different load types and storage systems. This VPCA organization uses a frame work based on data mining techniques to characterize the costumers. The paper includes results of several experimental tests cases, using real data and taking into account electricity generation resources as well as consumption data.

Self-managing agents for dynamic scheduling in manufacturing

The main purpose of this paper is to propose a Multi-Agent Autonomic and Bio-Inspired based framework with selfmanaging capabilities to solve complex scheduling problems using cooperative negotiation. Scheduling resolution requires the intervention of highly skilled human problem-solvers. This is a very hard and challenging domain because current systems are becoming more and more complex, distributed, interconnected and subject to rapidly changing. A natural Autonomic Computing (AC) evolution in relation to Current Computing is to provide systems with Self-Managing ability with a minimum human interference.