The in vitro toxicology of Swedish snus

Three commercial brands of Swedish snus (SWS), an experimental SWS, and the 2S3 reference moist snuff were each tested in four in vitro toxicology assays. These assays were: Salmonella reverse mutation, mouse lymphoma, in vitro micronucleus, and cytotoxicity. Water extractions of each of the 5 products were tested using several different concentrations; the experimental SWS was also extracted using dimethyl sulfoxide (DMSO). Extraction procedures were verified by nicotine determinations. Results for SWS in the mutagenicity assays were broadly negative: there were occasional positive responses, but these were effectively at the highest concentration only (concentrations well above those suggested by regulatory guidelines), and were often associated with cytotoxicity. The 2S3 reference was unequivocally positive in one of the three conditions of the micronucleus assay (MNA), at the highest concentration only. Positive controls produced the expected responses in each assay. The SWS data are contrasted with data reported for combusted tobacco in the form of cigarettes, where strongly positive responses have been routinely reported for mutagenicity and cytotoxicity. These negative findings in a laboratory setting concur with the large amount of epidemiological data from Sweden, data showing that SWS are associated with considerably lower carcinogenic potential when compared with cigarettes

Liquid exfoliation of solvent-stabilized few-layer black phosphorus for applications beyond electronics

Few-layer black phosphorus (BP) is a new two-dimensional material which is of great interest for applications, mainly in electronics. However, its lack of environmental stability severely limits its synthesis and processing. Here we demonstrate that high-quality, few-layer BP nanosheets, with controllable size and observable photoluminescence, can be produced in large quantities by liquid phase exfoliation under ambient conditions in solvents such as N-cyclohexyl-2-pyrrolidone (CHP). Nanosheets are surprisingly stable in CHP, probably due to the solvation shell protecting the nanosheets from reacting with water or oxygen. Experiments, supported by simulations, show reactions to occur only at the nanosheet edge, with the rate and extent of the reaction dependent on the water/oxygen content. We demonstrate that liquid-exfoliated BP nanosheets are potentially useful in a range of applications from ultrafast saturable absorbers to gas sensors to fillers for composite reinforcement

Search for long-lived particles decaying to leptons with large impact parameter in proton-proton collisions at root s=13 TeV

A search for new long-lived particles decaying to leptons using proton–proton collision data produced by the CERN LHC at s√=13TeV is presented. Events are selected with two leptons (an electron and a muon, two electrons, or two muons) that both have transverse impact parameter values between 0.01 and 10cm and are not required to form a common vertex. Data used for the analysis were collected with the CMS detector in 2016, 2017, and 2018, and correspond to an integrated luminosity of 118 (113)fb−1 in the ee channel (eμ and μμ channels). The search is designed to be sensitive to a wide range of models with displaced eμ, ee, and μμ final states. The results constrain several well-motivated models involving new long-lived particles that decay to displaced leptons. For some areas of the available phase space, these are the most stringent constraints to date

A invisibilidade da sorodiscordância na atenção às pessoas com HIV/AIDS The invisibility of serodiscordance in care for people with HIV/AIDS

Este estudo busca identificar e refletir sobre as estratégias médicas utilizadas a fim de garantir a importância do uso sistemático do preservativo na eficácia da prevenção à Aids, em especial, quando os pacientes estão envolvidos em relacionamentos conjugais sorodiscordantes, em que apenas um elemento do casal é portador do vírus HIV. Como instrumento de análise usamos os conceitos de estilos de pensamento da epistemologia (Fleck), de processo formativo (Good), e o de terapêutica (Sayd, Camargo Júnior e Almeida). Dentre os resultados encontrados na pesquisa, destacou-se uma invisibilidade dirigida aos casais sorodiscordantes, pois o que se revela como realmente importante é a adesão ao tratamento, que se confunde com adesão aos medicamentos (antirretrovirais).<br>This study seeks to identify and reflect on medical strategies used to ensure the systematic use of condoms for the effectiveness of AIDS prevention, in particular, when patients are involved in serodiscordant marital relationship in that only one of the partners is HIV positive. As analytical tools we used the concepts of thinking styles of epistemology (Fleck), the training process (Good), and therapeutics (Sayd, Camargo Jr. and Almeida). Among the findings of the research stood out an invisibility of the serodiscordant couples, for what turns out to be really important is adherence to treatment, which coincides with adherence to medication (ART)