RESUMO
Reinfection and multiple viral strains are among the latest challenges in the current COVID-19 pandemic. In contrast, epidemic models often consider a single strain and perennial immunity. To bridge this gap, we present a new epidemic model that simultaneously considers multiple viral strains and reinfection due to waning immunity. The model is general, applies to any viral disease and includes an optimal control formulation to seek a trade-off between the societal and economic costs of mitigation. We validate the model, with and without mitigation, in the light of the COVID-19 epidemic in England and in the state of Amazonas, Brazil. The model can derive optimal mitigation strategies for any number of viral strains, whilst also evaluating the effect of distinct mitigation costs on the infection levels. The results show that relaxations in the mitigation measures cause a rapid increase in the number of cases, and therefore demand more restrictive measures in the future.
Assuntos
Algoritmos , COVID-19/prevenção & controle , Modelos Teóricos , Viroses/prevenção & controle , Brasil/epidemiologia , COVID-19/epidemiologia , COVID-19/virologia , Simulação por Computador , Inglaterra/epidemiologia , Epidemias/prevenção & controle , Humanos , SARS-CoV-2/fisiologia , Viroses/epidemiologia , Viroses/virologiaRESUMO
This paper shows the use of exhaled air as a biomonitoring method to assess perchloroethylene (PERC) environmental and occupational exposure. A sensitive, fast, and solvent free analytical method was developed to determine PERC in ambient and exhaled air of individuals occupationally exposed. The developed method used cold fiber solid phase microextraction (CF-SPME) as the sampling technique, and a standard permeation method to simulation of air matrix. The analysis were conducted by gas chromatography coupled to mass spectrometry (GC/MS). The methods were validated and were found to be precise, linear and sensitive for environmental and biological monitoring. The developed methods were applied to twenty-seven sampling points spread across Belo Horizonte city, Brazil, twenty four dry cleaners, an electroplating industry, a research laboratory, and an automotive paint preparation shop. The results of ambient air analyses ranging from 14.0 to 3205.0µgm-3 with median concentration of 599.0µgm-3. Furthermore, sampling of exhaled air of individuals occupationally exposed presented results ranging from 6.0 to 2635.0µgm-3 with median concentration of 325.0µgm-3. The strong correlation observed between ambient and exhaled air (r =0.930) demonstrates that exhaled air is a suitable biomarker for evaluating occupational exposure to PERC.
Assuntos
Poluentes Ocupacionais do Ar/análise , Poluição do Ar em Ambientes Fechados/análise , Monitoramento Ambiental/métodos , Expiração , Exposição Ocupacional , Tetracloroetileno/análise , Adulto , Idoso , Biomarcadores/análise , Brasil , Testes Respiratórios , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Masculino , Pessoa de Meia-Idade , Microextração em Fase Sólida , Adulto JovemRESUMO
Acrolein is a pollutant released daily to the indoor environment from different sources. The present study reports the development of a simple and sensitive cold fiber solid phase microextraction sampling method for the determination of acrolein in exhaled air and indoor air by gas chromatography mass spectrometry. O-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine was used as derivatizing agent supported on a 65-µm polydimethylsiloxane-divinylbenzene SPME fiber. An acrolein permeation tube at 326.25 ng min-1 rate was used to generate gaseous standards. The method shows good results for main validation parameters. The limits of detection and quantification were 2.88 and 5.08 µg m-3, respectively, for indoor analysis; and 2.40 and 3.79 µg m-3, respectively, for exhaled air analysis. The precision showed standard deviation ranges from 6.00 to 8.00% for intra-assay analyses and from 8.00 to 10.00% for inter-assay analyses. After optimizing the conditions, analyses of real samples were performed on indoor environments contaminated by cigarette smoke, or heated oil, including pastry shops, restaurants, churros stands, and closed parking cars located in the city of Belo Horizonte, Brazil. Acrolein breaths of exposed people were also determined. A good Pearson correlation coefficient (r = 0.901) was observed between the concentration of acrolein in indoor air and exhaled air, allowing to propose acrolein breath as environmental exposure biomarker. Graphical Abstract Cold fiber solid phase microextraction gas chromatography/mass spectrometry.
Assuntos
Acroleína/análise , Poluição do Ar em Ambientes Fechados/análise , Testes Respiratórios/métodos , Monitoramento Ambiental/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Microextração em Fase Sólida/métodos , Acroleína/química , Humanos , Metais/química , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Humane education and the debate on alternatives to harmful animal use for training is a relatively recent issue in Brazil. While animal use in secondary education has been illegal since the late 1970s, animal use in higher science education is widespread. However, alternatives to animal experiments in research and testing have recently received attention from the Government, especially after the first legislation on animal experiments was passed, in 2008. This article proposes that higher science education should be based on a critical and humane approach. It outlines the recent establishment of the Brazilian Network for Humane Education (RedEH), as a result of the project, Mapping Animal Use for Undergraduate Education in Brazil, which was recognised by the 2014 Lush Prize. The network aims to create a platform to promote change in science education in Brazil, starting by quantitatively and qualitatively understanding animal use, developing new approaches adapted to the current needs in Brazil and Latin America, and communicating these initiatives nationally. This paper explores the trajectory of alternatives and replacement methods to harmful animal use in training and education, as well as the status of humane education in Brazil, from the point of view of educators and researchers engaged with the network.
Assuntos
Alternativas aos Testes com Animais/educação , Animais , Brasil , Humanismo , HumanosRESUMO
Coffee is a major tropical agricultural commodity and represents a significant fraction of the economy of many countries. However, certain plant and animal species can damage coffee crops, affecting trade. A solution to this issue is the use of pesticides, some of which are harmful to human health and the environment. This work consisted of the development of a multi-residue method for the analysis of pesticides in coffee by using LC-MS/MS. The QuEChERS extraction procedure was used. The following analytical parameters were optimised: selectivity, analytical range, linearity, LOD, LOQ, precision (RSD%) and recovery of the method. The results showed that the method is selective, as they were linear in the range of 10.0-100.0 µg kg(-1). The sensitivity, recovery and precision were adequate for the multi-residue analysis of pesticides in coffee. The method was applied to the analyses of 15 Brazilian coffee samples.