Percorrer por autor "Dias, Ricardo"
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- General Knowledge and Attitudes about Safety and Emergency Evacuation: The Case of a Higher Education InstitutionPublication . Carvalhais, Carlos; Dias, Ricardo; Costa, Carla; Silva, Manuela V.The implementation of a safety culture and awareness of emergency issues in buildings has been growing in more developed societies. It is essential that all occupants know how to act in an emergency situation, particularly during an emergency evacuation. In higher education institutions (HEIs), which annually host not only their many employees, but also national and international students, it is essential to know and understand the knowledge, attitudes, and behaviors that the academic community demonstrates in this matter. This study aimed to characterize the perception of occupants regarding safety, specifically in the emergency evacuation phase, within the academic community of an HEI. In this observational cross-sectional study, data on general knowledge and attitudes regarding safety and actions during emergency situations were collected through an anonymous questionnaire targeting students, faculty, and non-teaching staff, which was sent via institutional email. Valid responses were received from 392 participants and then scored and assessed on different domains. The results obtained showed that, despite a reasonable average regarding the general level of knowledge, attitudes, and behaviors of the occupants on the subject, the community falls somewhat short in terms of training. It is noteworthy that approximately 64% of the sample has never received awareness or training related to emergency evacuation, and around 68% are unaware of the location of their institution’s meeting/gathering point. Finally, by identifying the most common gaps, namely the training dimension, some simple measures could be improved, such as the dissemination of safety instructions accessible through QR codes placed in strategic locations or even conducting small drills during class sessions, as well as learning with simulation concerning different scenarios of emergency.
- Genome Sequencing of 10 Helicobacter pylori Pediatric Strains from Patients with Nonulcer Dyspepsia and Peptic Ulcer DiseasePublication . Nunes, Alexandra; Rocha, Raquel; Vale, Filipa F.; Vieira, Luís; Sampaio, Daniel A.; Dias, Ricardo; Gomes, João Paulo; Oleastro, MónicaWe present draft genome sequences of 10 Helicobacter pylori clinical strains isolated from children. This will be important for future studies of comparative genomics in order to better understand the virulence determinants underlying peptic ulcer disease.
- Sugar-based bactericides targeting phosphatidylethanolamine-enriched membranesPublication . Dias, Catarina; Pais, João P.; Nunes, Rafael; Blázquez-Sánchez, Maria-Teresa; Marquês, Joaquim T.; Almeida, Andreia F.; Serra, Patrícia; Xavier, Nuno M.; Vila-Viçosa, Diogo; Machuqueiro, Miguel; Viana, Ana S.; Martins, Alice; Santos, Maria S.; Pelerito, Ana; Dias, Ricardo; Tenreiro, Rogério; Oliveira, Maria C.; Contino, Marialessandra; Colabufo, Nicola A.; de Almeida, Rodrigo F.M.; Rauter, Amélia P.Anthrax is an infectious disease caused by Bacillus anthracis, a bioterrorism agent that develops resistance to clinically used antibiotics. Therefore, alternative mechanisms of action remain a challenge. Herein, we disclose deoxy glycosides responsible for specific carbohydrate-phospholipid interactions, causing phosphatidylethanolamine lamellar-to-inverted hexagonal phase transition and acting over B. anthracis and Bacillus cereus as potent and selective bactericides. Biological studies of the synthesized compound series differing in the anomeric atom, glycone configuration and deoxygenation pattern show that the latter is indeed a key modulator of efficacy and selectivity. Biomolecular simulations show no tendency to pore formation, whereas differential metabolomics and genomics rule out proteins as targets. Complete bacteria cell death in 10 min and cellular envelope disruption corroborate an effect over lipid polymorphism. Biophysical approaches show monolayer and bilayer reorganization with fast and high permeabilizing activity toward phosphatidylethanolamine membranes. Absence of bacterial resistance further supports this mechanism, triggering innovation on membrane-targeting antimicrobials.
- The expression of Helicobacter pylori tfs plasticity zone cluster is regulated by pH and adherence, and its composition is associated with differential gastric IL-8 secretionPublication . Silva, Bruno; Nunes, Alexandra; Vale, Filipa F; Rocha, Raquel; Gomes, João Paulo; Dias, Ricardo; Oleastro, MónicaBackground: Helicobacter pylori virulence is associated with different clinical outcomes. The existence of an intact dupA gene from tfs4b cluster has been suggested as a predictor for duodenal ulcer development. However, the role of tfs plasticity zone clusters in the development of ulcers remains unclear. We studied several H. pylori strains to characterize the gene arrangement of tfs3 and tfs4 clusters and their impact in the inflammatory response by infected gastric cells. Methods: The genome of 14 H. pylori strains isolated from Western patients, pediatric (n=10) and adult (n=4), was fully sequenced using the Illumina platform MiSeq, in addition to eight pediatric strains previously sequenced. These strains were used to infect human gastric cells, and the secreted interleukin-8 (IL-8) was quantified by ELISA. The expression of virB2, dupA, virB8, virB10, and virB6 was assessed by quantitative PCR in adherent and nonadherent fractions of H. pylori during in vitro co-infection, at different pH values. Results: We have found that cagA-positive H. pylori strains harboring a complete tfs plasticity zone cluster significantly induce increased production of IL-8 from gastric cells. We have also found that the region spanning from virB2 to virB10 genes constitutes an operon, whose expression is increased in the adherent fraction of bacteria during infection, as well as in both adherent and nonadherent fractions at acidic conditions. Conclusions: A complete tfs plasticity zone cluster is a virulence factor that may be important for the colonization of H. pylori and to the development of severe outcomes of the infection with cagA-positive strains.