Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
1.
Chemphyschem ; 25(10): e202300959, 2024 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-38409629

RESUMO

The activity and product selectivity of electrocatalysts for reactions like the carbon dioxide reduction reaction (CO2RR) are intimately dependent on the catalyst's structure and composition. While engineering catalytic surfaces can improve performance, discovering the key sets of rational design principles remains challenging due to limitations in modeling catalyst stability under operating conditions. Herein, we perform first-principles density functional calculations adopting implicit solvation methods with potential control to study the influence of adsorbates and applied potential on the stability of different facets of model Cu electrocatalysts. Using coverage dependencies extracted from microkinetic models, we describe an approach for calculating potential and adsorbate-dependent contributions to surface energies under reaction conditions, where Wulff constructions are used to understand the morphological evolution of Cu electrocatalysts under CO2RR conditions. We identify that CO*, a key reaction intermediate, exhibits higher kinetically and thermodynamically accessible coverages on (100) relative to (111) facets, which can translate into an increased relative stabilization of the (100) facet during CO2RR. Our results support the known tendency for increased (111) faceting of Cu nanoparticles under more reducing conditions and that the relative increase in (100) faceting observed under CO2RR conditions is likely attributed to differences in CO* coverage between these facets.

2.
Foods ; 12(14)2023 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-37509894

RESUMO

The COVID-19 pandemic raised questions and concerns about the possibility of the virus being transmitted through food, as the virus was found in sewage, shrimps and packages of frozen food. During the first wave of COVID-19, concerns about the transmission of SARS-CoV-2 through food arose. As the number of cases began to increase rapidly, so did the availability of information regarding the virus and ways to prevent infection. A significant portion of this information was disseminated by the media and the general public. Identifying and understanding the main doubts and concerns about food hygiene and safety raised by the Portuguese population during the first wave of COVID-19 is important in order to understand whether these issues have influenced their practices and what lessons can be learnt for food safety and hygiene education. The aims of this work were (1) to understand the doubts and concerns of the Portuguese population regarding food safety and hygiene during the first wave of COVID-19, and how these issues were clarified, (2) to analyze the population's opinion on food/hygiene myths and truths related to the transmission and prevention of the infection, and (3) to understand how the first wave of COVID-19 may have influenced the population's practices linked to food handling and consumption. The main doubts of the respondents were related to food handling (41.6%) and the possibility of transmission of COVID-19 through food (17%). Television was the main source of information used to clarify these doubts (32.9%), followed by a guideline issued by the Directorate-General of Health (30.7%). However, most respondents (50.9%) said that they had only found answers to some of their questions. Most respondents reported washing and disinfecting hands before (85% and 63.4%, respectively) and after (73.8% and 57.3%, respectively) the handling and organization of food purchases. Most respondents did not believe the myths about COVID-19 and food safety, but this depended on their level of education. Some practices may have changed as a result of the pandemic, particularly with regard to washing and disinfecting hands and food, as well as kitchen hygiene.

3.
Artigo em Inglês | MEDLINE | ID: mdl-36429805

RESUMO

Helicobacter species can colonize the gastrointestinal tract of both humans and animals, and are associated with gastrointestinal and extra-gastrointestinal diseases. Some studies indicate that animals, health professionals, and people in close contact with animals might be at higher risk for infection with gastric Helicobacter spp. Considering that veterinarians are professionals at risk for infection with zoonotic gastric Helicobacters and are also seen by many as health communicators concerning zoonoses, the aim of this study was to evaluate the Portuguese veterinarians' perception and knowledge of Helicobacter spp. infection and its zoonotic risk/potential. Therefore, a structured questionnaire composed of 34 dichotomic, multiple-choice, rating scale, matrix, drop-down, and open-ended questions was developed and given to Portuguese veterinarians via an online platform from May 2021 to July 2021, and statistical analysis was used to obtain results. There was a total of 149 respondents, most of them (73.8%) being females. Evidently, Portuguese veterinarians have a limited perception regarding Helicobacter spp. infections. Of the respondents that "have heard of Helicobacter", 17.6% do not know which animal species can be affected by it. Most of the companion animal veterinarians (76.2%) do not consider Helicobacter spp. infection a differential diagnosis when evaluating animals with gastritis. A significant percentage (37.2%) of the respondents that have "heard of H. suis" do not consider it a zoonotic bacterium. There is a need for education and sensitization of veterinarians regarding the potential zoonotic risk of Helicobacter spp. in order to elucidate these professionals to this One Health issue, as the number of reports of non-Helicobacter pylori Helicobacter in livestock, companion, and wild animals is increasing.


Assuntos
Gastrite , Infecções por Helicobacter , Helicobacter heilmannii , Helicobacter pylori , Helicobacter , Saúde Única , Médicos Veterinários , Humanos , Animais , Feminino , Masculino , Portugal/epidemiologia , Infecções por Helicobacter/epidemiologia , Percepção
4.
Data Brief ; 39: 107560, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34841016

RESUMO

This article describes a curated dataset entitled "Looking at Crime: Communities and Physical Spaces", which comprises data from different sources, namely Diagnosis of Local Security (DLS), Diagnosis of School Environment (DSE) and observation of physical spaces. The main topic covered was crime and related variables at the Historic Centre of Porto (HCP), a well-known urban area located in the North of Portugal. It is currently attended by inhabitants, workers, students and tourists. This dataset includes i) data from two different self-reports: i.1) demographics, perception of (in)security, victimization, social control and community cohesion obtained through an inquiry applied to the adult community; and i.2) data from school climate and students behavioural problems, which may be seen as risk factors for juvenile delinquency, collected through a web-survey applied to school personnel; and ii) data from observation of physical spaces, attending to the Crime Prevention through Environmental Design (CPTED) principles. The dataset allows descriptive and inferential statistical analyses, being useful for students, academics, stakeholders, police forces and policy-makers, to better understand crime and its related variables, forecast criminal incidents, and further develop associated preventive and intervention programmes.

5.
PLoS One ; 16(5): e0250980, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34010301

RESUMO

Campylobacter spp. are the most common bacterial pathogens associated with human gastroenteritis in industrialized countries. Contaminated chicken is the food vehicle associated with the majority of reported cases of campylobacteriosis, either by the consumption of undercooked meat or via cross- contamination of ready-to-eat (RTE) foods during the handling of contaminated raw chicken parts and carcasses. Our results indicate that cooking salt (used for seasoning) is a potential vehicle for Campylobacter spp. cross-contamination from raw chicken to lettuce, through unwashed hands after handling contaminated chicken. Cross-contamination events were observed even when the chicken skin was contaminated with low levels of Campylobacter spp. (ca. 1.48 Log CFU/g). The pathogen was recovered from seasoned lettuce samples when raw chicken was contaminated with levels ≥ 2.34 Log CFU/g. We also demonstrated that, once introduced into cooking salt, Campylobacter spp. are able to survive in a culturable state up to 4 hours. After six hours, although not detected following an enrichment period in culture medium, intact cells were observed by transmission electron microscopy. These findings reveal a "novel" indirect cross-contamination route of Campylobacter in domestic settings, and a putative contamination source to RTE foods that are seasoned with salt, that might occur if basic food hygiene practices are not adopted by consumers when preparing and cooking poultry dishes.


Assuntos
Campylobacter/isolamento & purificação , Galinhas/microbiologia , Microbiologia de Alimentos , Lactuca/microbiologia , Animais , Campylobacter/patogenicidade , Infecções por Campylobacter/transmissão , Contagem de Colônia Microbiana , Culinária , Contaminação de Equipamentos , Europa (Continente) , Manipulação de Alimentos/métodos , Inocuidade dos Alimentos , Gastroenterite/microbiologia , Higiene das Mãos , Humanos , Cloreto de Sódio na Dieta , Inquéritos e Questionários
6.
Compr Rev Food Sci Food Saf ; 20(3): 2716-2741, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33960652

RESUMO

Nontyphoidal salmonellae are among the most prevalent foodborne pathogens causing gastrointestinal infections worldwide. A high number of cases and outbreaks of salmonellosis are associated with the consumption of eggs and egg products, and several of these occur at the household level. The aim of the current study is to critically evaluate the current status of knowledge on Salmonella in eggs from a consumer's perspective, analyzing the hazard occurrence and the good practices that should be applied to reduce salmonellosis risk. Following a HACCP (Hazard Analysis and Critical Control Point) based approach, some steps along the food journey were identified as Critical Consumer Handling (CCH)-steps in which consumers, through their behavior or choice, can significantly reduce the level of Salmonella in eggs and egg products. From shopping/collecting to consumption, each of these steps is discussed in this review to provide an evidence-based overview of risk factors of human salmonellosis related to egg consumption. The main message to consumers is to choose Salmonella-free eggs (those that some official entity or producer guarantees that does not contain Salmonella), when available, especially for dishes that are not fully heat treated. Second, as guaranteed Salmonella-free eggs are only available in a few countries, refrigerated storage from the point of collection and proper cooking will significantly reduce the risk of salmonellosis. This will require a revision of the actual recommendations/regulations, as not all ensure that eggs are maintained at temperatures that prevent growth of Salmonella from collection until the time of purchasing.


Assuntos
Intoxicação Alimentar por Salmonella , Infecções por Salmonella , Ovos , Humanos , Fatores de Risco , Salmonella , Intoxicação Alimentar por Salmonella/epidemiologia , Infecções por Salmonella/epidemiologia
7.
ACS Nano ; 15(6): 10228-10240, 2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34003639

RESUMO

Liquid-cell scanning/transmission electron microscopy (S/TEM) has impacted our understanding of multiple areas of science, most notably nanostructure nucleation and growth and electrochemistry and corrosion. In the case of electrochemistry, the incorporation of electrodes requires the use of silicon nitride membranes to confine the liquid. The combined thickness of the liquid layer and the confining membranes prevents routine atomic-resolution characterization. Here, we show that by performing electrochemical water splitting in situ to generate a gas bubble, we can reduce the thickness of the liquid to a film approximately 30 nm thick that remains covering the sample. The reduced thickness of the liquid allows the acquisition of atomic-scale S/TEM images with chemical and valence analysis through electron energy loss spectroscopy (EELS) and structural analysis through selected area electron diffraction (SAED). This contrasts with a specimen cell entirely filled with liquid, where the broad plasmon peak from the liquid obscures the EELS signal from the sample and induces beam incoherence that impedes SAED analysis. The gas bubble generation is fully reversible, which allows alternating between a full cell and thin-film condition to obtain optimal experimental and analytical conditions, respectively. The methodology developed here can be applied to other scientific techniques, such as X-ray scattering, Raman spectroscopy, and X-ray photoelectron spectroscopy, allowing for a multi-modal, nanoscale understanding of solid-state samples in liquid media.

8.
ACS Appl Mater Interfaces ; 13(11): 13097-13105, 2021 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-33715346

RESUMO

The performance of metal-air batteries and fuel cells depends on the speed and efficiency of electrochemical oxygen reduction reactions at the cathode, which can be improved by engineering the atomic arrangement of cathode catalysts. It is, however, difficult to improve upon the performance of platinum nanoparticles in alkaline electrolytes with low-loading catalysts that can be manufactured at scale. Here, the authors synthesized nanoporous gold catalysts with increased (100) surface facets using electrochemical dealloying in sodium citrate surfactant electrolytes. These modified nanoporous gold catalysts achieved an 8% higher operating voltage and 30% greater power density in aluminum-air batteries over traditionally prepared nanoporous gold, and their performance was superior to commercial platinum nanoparticle electrodes at a 10 times lower mass loading. The authors used rotation disc electrode studies, backscattering of electrons, and underpotential deposition to show that the increased (100) facets improved the catalytic activity of citrate dealloyed nanoporous gold compared to conventional nanoporous gold. The citrate dealloyed samples also had the highest stability and least concentration of steps and kinks. The developed synthesis and characterization techniques will enable the design and synthesis of metal nanostructured catalysts with controlled facets for low-cost and mass production of metal-air battery cathodes.

9.
Int J Food Microbiol ; 338: 108984, 2021 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-33277046

RESUMO

Contaminated poultry is the major vehicle for consumer's exposure to Campylobacter. This study aimed to perceive potential cross-contamination events during preparation of raw poultry that can contribute to the spread of Campylobacter spp. in domestic kitchen environments and to understand consumers' meanings and justifications on preparation of a poultry dish at home. A total of 18 households were visited to observe consumers preparing a recipe that included poultry. Poultry samples and swabs from the kitchen surfaces and utensils, such as kitchen cloth, hand towel, sponge, cutting boards and the sink, were collected before and after food preparation and tested for the presence of Campylobacter spp. Genotypic characterization of 72 Campylobacter spp. isolates was carried out through Pulse-Field Gel Electrophoresis (PFGE). Fourteen chicken samples were contaminated with Campylobacter spp. (77.8%). Twelve consumers (66.6%) washed the chicken meat under running tap water and eight (44.4%) used cutting boards. Also, only five consumers washed their hands properly prior to or during meal preparation. Cross-contamination events were detected in four kitchens, between the raw chicken and two cutting boards, two sinks and one kitchen cloth. The poultry samples presented different levels of contamination (< 4.0 × 101 CFU/g to 2.2 × 103 CFU/g), being some poultry with lower Campylobacter loads the origin of three cross-contamination events during food preparation. Both C. jejuni and C. coli were recovered. Molecular typing by PFGE showed a high diversity among the isolates. There were different explanations for the practice of cleaning and rinsing chicken, but, in general, it is an habit linked to what they have learned from their families. These results highlight the potential for the dissemination of Campylobacter strains in the domestic environment through the preparation of chicken meat and the need to raise awareness among consumers for an appropriate handling of raw poultry in order to decrease the risk of campylobacteriosis.


Assuntos
Infecções por Campylobacter/microbiologia , Contaminação de Alimentos/análise , Contaminação de Alimentos/prevenção & controle , Manipulação de Alimentos/métodos , Manipulação de Alimentos/normas , Microbiologia de Alimentos , Animais , Campylobacter/genética , Galinhas , Genes Bacterianos/genética , Genótipo , Carne/microbiologia
10.
Artigo em Inglês | MEDLINE | ID: mdl-31731572

RESUMO

Health promotion and inequality reduction are specific goals of the United Nations 2030 Agenda, which are interconnected with several dimensions of life. This work proposes a composite index SEHVI-socioeconomic health vulnerability index-to address Portuguese population socioeconomic determinants that affect health outcomes. Variables composing SEHVI are aligned with the sustainable development goals considering data and times series availability to enable progress monitoring, and variables adequacy to translate populations' life conditions affecting health outcomes. Data for 35 variables and three periods were collected from official national databases. All variables are part of one of the groups: Health determinants (social, economic, cultural, and environmental factors) and health outcomes (mortality indicators). Variables were standardized and normalized by "Distance to a reference" method and then aggregated into the SEHVI formula. Several statistical procedures for validation of SEHVI revealed the internal consistency of the index. For all municipalities, SEHVI was calculated and cartographically represented. Results were analyzed by statistical tests and compared for three years and territory typologies. SEHVI differences were found as a function of population density, suggesting inequalities of communities' life conditions and in vulnerability to health.


Assuntos
Promoção da Saúde , Disparidades nos Níveis de Saúde , Bases de Dados Factuais , Demografia , Nível de Saúde , Humanos , Portugal , População Rural , Determinantes Sociais da Saúde , Nações Unidas , População Urbana
11.
Artigo em Inglês | MEDLINE | ID: mdl-30832447

RESUMO

Medicine is a knowledge area continuously experiencing changes. Every day, discoveries and procedures are tested with the goal of providing improved service and quality of life to patients. With the evolution of computer science, multiple areas experienced an increase in productivity with the implementation of new technical solutions. Medicine is no exception. Providing healthcare services in the future will involve the storage and manipulation of large volumes of data (big data) from medical records, requiring the integration of different data sources, for a multitude of purposes, such as prediction, prevention, personalization, participation, and becoming digital. Data integration and data sharing will be essential to achieve these goals. Our work focuses on the development of a framework process for the integration of data from different sources to increase its usability potential. We integrated data from an internal hospital database, external data, and also structured data resulting from natural language processing (NPL) applied to electronic medical records. An extract-transform and load (ETL) process was used to merge different data sources into a single one, allowing more effective use of these data and, eventually, contributing to more efficient use of the available resources.


Assuntos
Atenção à Saúde , Armazenamento e Recuperação da Informação/métodos , Pesquisa Biomédica , Redes Comunitárias , Bases de Dados Factuais , Registros Eletrônicos de Saúde , Humanos , Disseminação de Informação , Qualidade de Vida
12.
ACS Appl Mater Interfaces ; 10(25): 21224-21234, 2018 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-29851338

RESUMO

The decomposition of H2O2 to H2O and O2 catalyzed by platinum nanocatalysts controls the energy yield of several energy conversion technologies, such as hydrogen fuel cells. However, the reaction mechanism and rate-limiting step of this reaction have been unsolved for more than 100 years. We determined both the reaction mechanism and rate-limiting step by studying the effect of different reaction conditions, nanoparticle size, and surface composition on the rates of H2O2 decomposition by three platinum nanocatalysts with average particle sizes of 3, 11, and 22 nm. Rate models indicate that the reaction pathway of H2O2 decomposition is similar for all three nanocatalysts. Larger particle size correlates with lower activation energy and enhanced catalytic activity, explained by a smaller work function for larger platinum particles, which favors chemisorption of oxygen onto platinum to form Pt(O). Our experiments also showed that incorporation of oxygen at the nanocatalyst surface results in a faster reaction rate because the rate-limiting step is skipped in the first cycle of reaction. Taken together, these results indicate that the reaction proceeds in two cyclic steps and that step 1 is the rate-limiting step. Step 1: Pt + H2 O2 → H2 O + Pt( O). Step 2: Pt( O) + H2 O2 → Pt + O2 + H2 O. Overall: 2 H2 O2 → O2 + 2 H2 O. Establishing relationships between the properties of commercial nanocatalysts and their catalytic activity, as we have done here for platinum in the decomposition of H2O2, opens the possibility of improving the performance of nanocatalysts used in applications. This study also demonstrates the advantage of combining detailed characterization and systematic reactivity experiments to understand property-behavior relationships.

14.
Langmuir ; 30(49): 14999-5008, 2014 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-25409484

RESUMO

A novel, fast, and easy mechano-chemistry-based (dry milling) method has been developed to exfoliate graphene with hydrophobic drugs generating few-layer graphene mesosheets (< 10 nm in thickness and ∼1 µm in width). The electronic properties of the graphitic structure were partially preserved after the milling treatment compared with graphene oxide prepared by Hummers' method. Several characterization techniques such as thermogravimetric analysis, Raman spectroscopy, atomic force microscopy, electron microscopy, and molecular dynamics simulation were used to characterize this material. The drug-exfoliated mesosheets were pharmacologically inactive, offering a new approach for making water-soluble few-layer graphene mesosheets upon dry milling with hydrophobic drugs, mainly used as exfoliating agents.


Assuntos
Anfotericina B/farmacologia , Grafite/química , Água/química , Antibacterianos/farmacologia , Interações Hidrofóbicas e Hidrofílicas/efeitos dos fármacos , Microscopia de Força Atômica , Simulação de Dinâmica Molecular , Solubilidade , Propriedades de Superfície
15.
ISRN Obstet Gynecol ; 2013: 851712, 2013 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-24191199

RESUMO

Listeria was first described in 1926 by Murray, Webb, and Swann, who discovered it while investigating an epidemic infection among laboratory rabbits and guinea pigs. The role of Listeria monocytogenes as a foodborne pathogen was definitively recognized during the 1980s. This recognition was the consequence of a number of epidemic human outbreaks due to the consumption of contaminated foods, in Canada, in the USA and in Europe. Listeriosis is especially severe in immunocompromised individuals such as pregnant women. The disease has a low incidence of infection, although this is undeniably increasing, with a high fatality rate amongst those infected. In pregnant women listeriosis may cause abortion, fetal death, or neonatal morbidity in the form of septicemia and meningitis. Improved education concerning the disease, its transmission, and prevention measures for immunocompromised individuals and pregnant women has been identified as a pressing need.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...