Hematological problems are associated with Coronavirus disease 2019 (COVID-19). Respiratory impairment is the higher point studied, although without experimental studies related to the oxygen transport performed by erythrocytes. Therefore, we decided to investigate if erythrocytes from COVID-19 patients have their functionality changed. The case-control study included hospitalized patients with a positive real-time polymerase chain reaction (RT-PCR) result admitted to University Hospital. Volunteers (negative RT-PCR results) were recruited as a control group. Thus, we assessed different erythrocytes parameters, oxidative stress markers, and biophysical studies using whole blood and isolated hemoglobin. We found a decrease of 51% in oxygen uptake and reduced antioxidant enzyme activity in COVID-19 patients compared to controls. Raman spectrometry showed structural changes in the hemoglobin and lipids of the erythrocytes from COVID-19 patients; thus, these results were consolidated with an increase in Young’s modulus in erythrocytes followed by morphology changes. Besides, isolated hemoglobin from COVID-19 patients has a distinct interaction profile using a ligand model compared to the control. COVID-19 leads to structural, functional, and morphological damage to human erythrocytes. Our data showed structural and molecular changes and induction of oxidative stress in erythrocytes by COVID-19, a new perspective on the contribution of erythrocytes to a respiratory commitment in COVID-19.

Abstract Uncaria tomentosa is a plant native to the Amazon that has immunomodulatory and antitumor properties due to the alkaloids found in the plant, being able to modify the immune response by potentiating or suspending the action of cytokines secreted by macrophages that induce the immune response, either by the classical route (M1) or through the alternative route (M2). Macrophages activated by M1 convert L-arginine into L-citrulline and nitric oxide (NO), whereas macrophages activated by the M2 pathway use the enzymatic activity of arginase to convert the same substrate into L-ornithine and urea. The aim of this work was to evaluate the immunostimulating activity of the crude hydroalcoholic extract from the bark of the U. tomentosa stem in RAW 264.7 macrophages. Concentrations of 0.2, 0.1 and 0.05 mg/mL of U. tomentosa extract associated with LPS, INF-γ and IL-4 inducers were tested by determining NO production and arginase enzyme activity. Nitric oxide production was enhanced by the extract when associated with LPS and LPS + INF-γ inducers. In the activity of the arginase enzyme, the extract decreased the stimulation of IL-4 on the enzyme, mainly at 0.2 mg/mL concentration. Therefore, it is concluded that the crude hydroalcoholic extract of the stem bark of U. tomentosa in RAW 264.7 cells, at a concentration of 0.2 mg/mL, showed considerable pro-inflammatory activity.

Resumo A Uncaria tomentosa é uma planta nativa da Amazônia que possui propriedades imunomoduladoras e antitumorais devido aos alcaloides encontrados no vegetal, sendo capaz de modificar a resposta imune ao potencializar ou suspender a ação de citocinas secretadas por macrófagos que induzem a resposta imune, seja pela via clássica (M1) ou pela via alternativa (M2). Macrófagos ativados pela M1 converte L-arginina em L-citrulina e óxido nítrico (NO), já os macrófagos ativados pela via M2 utilizam a atividade enzimática da arginase para converter o mesmo substrato em L-ornitina e ureia. O trabalho teve como objetivo avaliar a atividade imunoestimuladora do extrato hidroalcoólico bruto da casca do caule da U. tomentosa em macrófagos RAW 264.7. Foram testadas as concentrações 0.2, 0.1 e 0.05 mg/mL do extrato de U. tomentosa associadas aos indutores LPS, INF-γ e IL-4, por meio da determinação da produção de NO e atividade da enzima arginase. A produção de óxido nítrico foi potencializada pelo extrato quando associado aos indutores LPS e LPS + INF-γ. Na atividade da enzima arginase, o extrato diminuiu a estimulação da IL-4 sobre a enzima, principalmente na concentração 0.2 mg/mL. Portanto, conclui-se que o extrato hidroalcoólico bruto da casca do caule de U. tomentosa em células RAW 264.7, na concentração 0.2 mg/mL, demostrou atividade pró-inflamatória considerável.

Abstract ZnO-NPs can be obtained through various methods, resulting in nanoparticles with different size and morphology, which directly influences their antimicrobial potential. The objective of this work was to evaluate the antibacterial activity of ZnO-NPs obtained by a solochemical process against important human foodborne pathogens: Staphylococcus aureus, Salmonella Typhimurium, Bacillus cereus and Pseudomonas aeruginosa. ZnO-NPs were identified as nanorods with the length between 90.1 and 100 nm (10.5 % frequency), the diameter between 80.1 and 90 nm (21 % frequency), and wurtzite type crystalline structure. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were equal to 0.05 mg mL-1 and 0.5 mg mL-1 for S. aureus and S. Typhimurium, respectively, lower than previous results related in the literature. ZnO-NPs produced by solochemical method had a superior antibacterial activity. For instance, they can be incorporated in packaging materials for increasing microbial safety and food shelf-life by inhibiting bacterial growth.

Nine new compounds derived from selenoglycolic acid were synthesized, and their structures were fully characterized by elemental analysis, infrared (IR), 1H and 13C nuclear magnetic resonance (NMR). The compounds were evaluated in an in silico study and showed strong to moderate antibacterial activity against several strains of Staphylococcus aureus. In particular, three compounds exhibited excellent antibacterial activity, with minimum inhibitory concentrations (MICs) between 16 and 64 µg mL-1. Furthermore, two of the nine compounds showed antifungal activity, with MIC of 1024 and 512 µg mL-1. In silico studies of the parameters of Lipinski's rule of five indicate that these compounds have potential to be new drug candidates.

A produção de revestimentos cerâmicos pelo processo monoqueima é atualmente o mais difundido entre as empresas de cerâmica. O processo de queima está em constante evolução e adaptação à novos parâmetros, devido ao crescimento tecnológico e à diversificação dos produtos cerâmicos. É necessário entender o mecanismos envolvidos na queima de placas cerâmicas utilizando fornos a rolos, principalmente o desempenho térmico do equipamento e características técnicas dos revestimentos cerâmicos. Neste trabalho, um modelo matemático e um procedimento experimental foram aplicados para determinar a cinética de retração. Os parâmetros cinéticos foram determinados experimentalmente, utilizando pó industrial para obter corpos-de-prova de 80 x 20 x 2,3 mm³ queimados em forno elétrico laboratorial a rolo. A energia de ativação, Ea =178041 J/mol, o expoente do tempo "n" que determina o mecanismo de sinterização, n = 0,26285 e fator de freqüência, k0 = 44768 s-1 foram determinados depois de distintas condições de queima em 30, 40 e 50 min de frio a frio e as temperaturas entre 1000 a 1150 °C (com passos de 30 °C).

The firing process is the core of the tiles production, currently the single-cycle firing is the most widespread method in ceramic industries. Moreover, the increasing demand of technological improvements and technical diversifications of ceramic products, leads the firing process to continuously adapt to new operative conditions. The physical mechanisms that occur in roller kilns have to be understood, mainly those involving thermal performance of the equipment and technical characteristics of the ceramic tiles. In this work, a mathematical model and an experimental procedure has been applied to determine the shrinkage kinetics. The kinetic parameters have been experimentally determined using industrial powder to obtain test pieces of 80 x 20 x 2.3 mm³ fired in laboratory electrical roller kiln. Activation energy, Ea=178 kJ/mol, parameter "n", n=0.26285 and frequency factor, k0=44768 s-1 were determined after several firing conditions 30, 40 and 50 min cold-to-cold and temperatures from 1000 to 1150 ºC (steps of 30 ºC).