Peptide-capped Au and Ag nanoparticles: Detection of heavy metals and photochemical core/shell formation.

We present a short peptide of only six amino acids that can be used in ambient conditions to simultaneously reduce either Au3+ or Ag+ ions, forming nanoparticles, and function as a stabilizing capping agent. At acidic pH, Hg2+ ions oxidize the silver nanoparticles and Fe2+ ions promote the aggregation of the gold nanoparticles. At alkaline conditions, Mn2+ ions induce the aggregation of the silver nanoparticles. Through the absorbance changes of these processes, these peptide-capped nanoparticles demonstrated a fast, selective, and sensitive pH-dependent detection system. The limit of detection of Hg2+, Mn2+, and Fe2+ was 319 nм, 184 nм, and 320 nм, respectively. Furthermore, the formed gold nanoparticles were successfully enveloped by a silver shell in a peptide-mediated photoreduction process. These bimetallic Au@Ag core/shell nanoparticles were characterized using UV-vis spectroscopy, high-resolution scanning transmission electron microscopy (HR-STEM), and energy dispersive X-ray spectroscopy (EDS). While prior studies used peptides as ligands for nanoparticles, the versatile abilities of the novel peptide presented in this study display the promising potential of using peptides for nanoparticles synthesis. This is because a single peptide can be used in a single-step one-pot synthesis to prepare and stabilize AuNPs, AgNPs, and Au@Ag core/shell nanoparticles, while also allowing to selectively probe different metal ions.

A Novel Copper-Binding Peptide That Self-Assembles Into a Transparent Antibacterial and Antiviral Coating.

The health, economy, and quality of life all over the world are greatly affected by bacterial infections and viral outbreaks. Bacterial cells and viruses, such as influenza, can spread through contaminated surfaces and fomites. Therefore, a possible way to fight these pathogens is to utilize antibacterial and antiviral coatings, which reduce their numbers on contaminated surfaces. Here, we present a novel short peptide that can self-assemble, adhere to various surfaces, and bind different metal ions such as copper, which provides the surface with antibacterial and antiviral properties. For these functions, the peptide incorporates the amino acid 3,4-dihydroxyphenylalanine (DOPA), which provides the peptide with adhesive capabilities; a diphenylalanine motif that induces the self-assembly of the peptide; the metal-binding hexahistidine sequence. Our results demonstrate that the coating, which releases monovalent cuprous ions and hydrogen peroxide, provides the surfaces with significant antibacterial and antiviral properties. Additionally, the coating remains transparent, which is favorable for many objects and especially for display screens.

Workers of São Paulo city, Brazil, exposed to air pollution: Assessment of genotoxicity.

Air pollution affects all major urban centers, particularly megacities with populations greater than 10 million people. Vehicular and industrial emissions are among the most important sources of air pollutants in these cities. Air pollution composition, dose, and time of exposure can cause differential effects on human health. We have evaluated the genotoxic effects of air pollution (PM2.5 and NO2) on São Paulo city workers. Fifty-seven male individuals, 28-66 years old, with occupational exposure to air pollution, participated in this study; all worked daily outdoor shifts in São Paulo. Participants were recruited from three occupations: traffic controllers (n = 18); taxi drivers (n = 21); and workers at the Forestry Institute (n = 18). These workers were classified into two groups based on their workplace locations: Downtown Group (DT): traffic controllers and taxi drivers; Outskirts of Town Group (OT): workers at the Forestry Institute. Individual samplers of air pollution (Harvard air impactor) were used to collect PM2.5 and NO2 pollutants. Genotoxicity analysis (micronucleus test) was performed on buccal mucosa epithelial cells and peripheral blood lymphocytes. PM2.5 concentrations were significantly different between the groups (DT = 32.92 µg m-3, OT = 25.77 µg m-3; p = 0.03); however, no difference was observed in NO2 concentrations. Micronucleus frequencies in both buccal mucosa (DT = 2.78%, OT = 1.16%; p < 0.0001) and in peripheral lymphocytes (DT = 1.51%, OT = 0.73%; p < 0.0001) were significantly different between the groups. We observed a direct correlation between the individual dose of PM2.5 and micronucleus frequency in the buccal mucosa (p = 0.0021). Our results indicate that workers in the most urban areas of São Paulo are exposed to higher concentrations of PM2.5 and showed higher micronucleus frequencies in both buccal mucosa and lymphocytes.

As expectativas profissionais dos alunos universitários na maturidade / The professional expectations of university students in the maturity

Esta pesquisa teve como objetivo investigar os motivos que têm conduzidopessoas na maturidade a ingressar em cursos superiores de graduação e suasexpectativas após a formatura. Trata-se de uma pesquisa qualitativa realizada por meiode entrevista com alunos acima de 50 anos de idade. Nossos resultados mostraram que50% dos sujeitos entrevistados buscam uma atualização cultural e 100% delespretendem exercer a nova carreira. Concluímos que a busca por atualização é umacaracterística humana já que sua existência é um processo contínuo de desenvolvimentode seus projetos de vida.AU

This research had as objective to investigate the reasons that people inthe maturity age have lead to enter in superior courses of graduation and itsexpectations after their formation. This work is a carried through qualitative researchthrough interview with 50 years old or above students. Our results had shown that 50%of the interviewed search a cultural update and 100% of them intend to exert the newcareer. We conclude that the search for a cultural update is a human beingcharacteristic since its existence is a continuous process of development of its projectsof life.AU

As expectativas profissionais dos alunos universitários na maturidade / The professional expectations of university students in the maturity

Esta pesquisa teve como objetivo investigar os motivos que têm conduzidopessoas na maturidade a ingressar em cursos superiores de graduação e suasexpectativas após a formatura. Trata-se de uma pesquisa qualitativa realizada por meiode entrevista com alunos acima de 50 anos de idade. Nossos resultados mostraram que50 dos sujeitos entrevistados buscam uma atualização cultural e 100 deles pretendem exercer a nova carreira. Concluímos que a busca por atualização é umacaracterística humana já que sua existência é um processo contínuo de desenvolvimentode seus projetos de vida.

This research had as objective to investigate the reasons that people inthe maturity age have lead to enter in superior courses of graduation and itsexpectations after their formation. This work is a carried through qualitative researchthrough interview with 50 years old or above students. Our results had shown that 50 of the interviewed search a cultural update and 100 of them intend to exert the newcareer. We conclude that the search for a cultural update is a human beingcharacteristic since its existence is a continuous process of development of its projectsof life.