Assessment of SARS-CoV-2 infection in a basic health service unit in Araçatuba, São Paulo, Brazil / Incidência de infecção por SARS-Cov-2 em uma unidade básica de Saúde de Araçatuba, São Paulo, Brasil

Objective: to describe risk factors associated with SARS-CoV-2 infection. Methods: this is a retrospective descriptive cross-sectional study aimed at describing the epidemiological profile of laboratory and clinical diagnosis of unvaccinated patients seen at a basic health unit in Araçatuba ­ SP, infected with SARS-CoV-2 between June 2020 and January 2021.The results were analyzed through inferential and descriptive statistics. Additionally, Chi-square and Fisher exact tests were used (p<0.05). Results: of 313 patients, 128 were positive for COVID-19, with 68.75% diagnosed by RT-PCR and the others by immunochromatography. Women were 51.56% of those infected with adults corresponding to the main age group (76.56%), and 57% of patients had only a basic educational level concluded. A total of 88.26% of the patients progressed to cure without complications; eight patients died, most of whom were men and elderly. Of the variables analyzed for positive/negative outcomes, only "basic educational level" was significant for a positive result(p=0.0019). Conclusion: the deaths of infected patients may be associated with the existence of at least one comorbidity and advanced age of men.

Objetivo: descrever os fatores de risco associados com a infecção por SARS-CoV-2. Métodos: trata-se de um estudo descritivo retrospectivo e transversal, voltado a descrever o perfil epidemiológico de diagnóstico laboratorial e clínico, de pacientes não vacinados, atendidos em uma unidade básica de saúde de Araçatuba-SP, infectados por SARS-CoV-2, no período entre junho de 2020 e janeiro de 2021. Os resultados foram analisados por estatística inferencial e descritiva. Adicionalmente, foram aplicados os testes de Qui-quadrado e exato de Fisher (p<0.05). Resultados: dos 313 pacientes, 128 apresentaram resultado positivo para COVID-19, com 68,75% diagnosticados por RT-PCR e o restante por imunocromatografia. Mulheres foram 51,56% dos infectados, com adultos correspondendo à principal faixa etária (76,56%), 57% dos pacientes apresentavam apenas o nível educacional básico concluído. O quadro de 88.26%dos pacientes evoluiu para cura sem complicações;8 pacientes foram a óbito, sendo, em sua maioria, homens e idosos. Das variáveis analisadas para grau de dependência de resultado positivo/negativo, apenas "nível escolar básico" apresentou resultado significante para resultado positivo (p=0.0019). Conclusão: os óbitos dos pacientes infectados podem ser associados à existência de, pelo menos, uma comorbidade e à idade avançada de homens.

Gold Nanodisks Plasmonic Array for Hydrogen Sensing at Low Temperature.

We present a novel plasmonic hydrogen sensor consisting of an array of gold nanodisks produced by lithography. The size, height, and spacing of the disks were optimized using finite element simulation to generate a sharp localized surface plasmon resonance peak in the near-infrared wavelength region. The reported results show the possibility of developing an optical gas sensors-based bare Au nanostructures operating at a low temperature.

Degenerately Doped Metal Oxide Nanocrystals as Plasmonic and Chemoresistive Gas Sensors.

Highly doped wide band gap metal oxide nanocrystals have recently been proposed as building blocks for applications as transparent electrodes, electrochromics, plasmonics, and optoelectronics in general. Here we demonstrate the application of gallium-doped zinc oxide (GZO) nanocrystals as novel plasmonic and chemiresistive sensors for the detection of hazardous gases including hydrogen (H2) and nitrogen dioxide (NO2). GZO nanocrystals with a tunable surface plasmon resonance in the near-infrared are obtained using a colloidal heat-up synthesis. Thanks to the strong sensitivity of the plasmon resonances to chemical and electrical changes occurring at the surface of the nanocrystals, such optical features can be used to detect the presence of toxic gases. By monitoring the changes in the dopant-induced plasmon resonance in the near-infrared, we demonstrate that GZO thin films prepared depositing an assembly of highly doped GZO colloids are able to optically detect both oxidizing and reducing gases at mild (<100 °C) operating temperatures. Combined optical and electrical measurements show that trivalent dopants within ZnO nanocrystals enhance the gas sensing response compared to undoped ZnO. Moreover, improved sub-ppm of NO2 gas sensitivity is achieved by activating the sensors response through combined purple-blue (λ = 430 nm) light irradiation and mild heating at 75 °C. In addition, these thin films based on degenerately doped semiconductors are highly transparent in the visible range, enabling the fabrication of "invisible" gas sensors. The use of highly doped semiconductive nanocrystals for both IR plasmonic and chemiresistive sensors represent a marked advancement toward the development of highly sensitive and selective devices.

Analysis of defect luminescence in Ga-doped ZnO nanoparticles.

We applied cathodoluminescence (CL) spectroscopy to evaluate the defect-induced luminescence within ZnO and Ga-doped ZnO (GZO) nanoparticles. The observed emissions from defect sites present in the GZO lattice exhibited a strong dependence on both dopant content and synthesis methods. The strong and broad defect-induced emissions and inhomogeneous population of intrinsic defects in nano-sized ZnO particles could effectively be suppressed by Ga doping, although large dopant amounts caused the generation of negatively-charged defects, VZn and Oi, with a subsequent increase of the luminescence. Upon deconvolution of the retrieved CL spectra into individual sub-bands, the physical origin of all the sub-bands could be clarified, and related to sample composition and synthesis protocol. This study lays the foundation of quantitative CL evaluation of defects to assess the quality of GZO optoelectronic devices.