Abstract The blend of butadiene and acrylonitrile copolymer (NBR) with natural poly-cis-isoprene (NR) shows increased resistance to swelling in solvents in comparison to the individual components. In aerospace, NBR rubber is used as thermal protection for rockets and shall not contain other polymers, even in low contents, otherwise, it can affect the protection performance and rocket safety by causing detachment of the elastomer/propellant interface; therefore, this investigation presents methodologies to determine the NR/NBR contents. This study explores different analytical techniques, such as Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy, in the mid-infrared (MIR) by reflection and in the near-infrared by reflectance (NIRA) modes, Furthermore, quantification strategies by univariate, bivariate and multivariate (chemometric) models are evaluated and compared. A proposed methodology, based on multivariate Raman microscopy with partial least squares regression (PLS), showed high linearity (R2 > 0.99) and low error (< 0.82 %). The validation of FT-MIR data for the CH3, which presented lower error (1.3%) than vinylidene band (6%), showed that both methodologies (reflection and NIRA reflectance) can be used for the quantification of NR in NR/NBR. These results constitute a contribution to the state of the art in researching industrial and aerospace elastomeric applications. (NBR polycisisoprene poly cis isoprene (NR components polymers contents otherwise elastomerpropellant elastomer propellant interface therefore NRNBR techniques FTIR (FTIR midinfrared mid MIR (MIR nearinfrared near (NIRA modes Furthermore univariate chemometric (chemometric compared methodology PLS, PLS , (PLS) R2 R (R 0.99 099 0 99 < ( 082 82 0.8 %. % . %) FTMIR FT CH3 CH 1.3% 13 1 3 (1.3% 6%, 6 6% (6%) applications (PLS 0.9 09 9 08 8 0. 1.3 (1.3 (6% 1. (1. (6 (1

ABSTRACT Objective Neck circumference is a simple anthropometric measurement that may be linked to chronic diseases, physical activity, and muscle strength. We sought to verify the association of moderate and vigorous physical activity levels and relative muscle strength with neck circumference in a community in southern Brazil. Methods We cross-sectionally analyzed data from 2,488 participants (51% women), aged 20-79 years old from the Study of Health in Pomerode (SHIP-Brazil) conducted in Pomerode, Santa Catarina, Brazil. Increased neck circumference was defined with cutoff points of >39cm for men and >35cm for women. The independent variables were the level of moderate and vigorous physical activity using the short International Physical Activity Questionnaire, and relative muscle strength using the handgrip test and body mass. Univariate and multiple Poisson regression models were used to determine the association between variables (p≤0.05). Results The prevalence of increased neck circumference was 48.2% (60.4% in men, 39.6% in women) and was associated with low relative muscle strength (PR=1.26, 95%CI: 1.17-1.35) in men, insufficient moderate and vigorous physical activity levels (PR=1.23, 95%CI: 1.14-1.32), and relative muscle strength (PR=1.73, 95%CI: 1.61-1.87) in women. After adjusting for covariates, no significant associations were observed between insufficient moderate and vigorous physical activity levels in men (PR=1.02, 95%CI: 0.95-1.07). Conclusion Increased neck circumference seems to be an important predictor of low moderate and vigorous physical activity and relative strength loss in adults, and more pronounced in women. diseases Brazil crosssectionally cross sectionally 2488 2 488 2,48 51% 51 (51 women, women , 2079 20 79 20-7 SHIPBrazil SHIP (SHIP-Brazil Catarina 39cm cm 35cm Questionnaire mass p≤0.05. p005 p p≤0.05 . 0 05 (p≤0.05) 482 48 48.2 60.4% 604 60 4 (60.4 396 39 6 39.6 PR=1.26, PR126 PR 1 26 (PR=1.26 95%CI 95CI CI 95 1.171.35 117135 1.17 1.35 17 35 1.17-1.35 PR=1.23, PR123 23 (PR=1.23 1.141.32, 114132 1.14 1.32 14 32 1.14-1.32) PR=1.73, PR173 73 (PR=1.73 1.611.87 161187 1.61 1.87 61 87 1.61-1.87 covariates PR=1.02, PR102 02 (PR=1.02 0.951.07. 095107 0.95 1.07 07 0.95-1.07) adults 248 2,4 5 (5 207 7 20- p00 p≤0.0 (p≤0.05 48. 60.4 (60. 3 39. PR=1.26 PR12 (PR=1.2 9 171 1.171.3 11713 117 1.1 135 1.3 1.17-1.3 PR=1.23 141 1.141.32 11413 114 132 1.14-1.32 PR=1.73 PR17 (PR=1.7 611 1.611.8 16118 161 1.6 187 1.8 8 1.61-1.8 PR=1.02 PR10 (PR=1.0 951 0.951.07 09510 095 0.9 107 1.0 0.95-1.07 24 2, ( p0 p≤0. (p≤0.0 60. (60 PR=1.2 PR1 (PR=1. 1.171. 1171 11 1. 13 1.17-1. 1.141.3 1141 1.14-1.3 PR=1.7 1.611. 1611 16 18 1.61-1. PR=1.0 0.951.0 0951 09 0. 10 0.95-1.0 p≤0 (p≤0. (6 PR=1. (PR=1 1.171 1.17-1 1.141. 1.14-1. 1.611 1.61-1 0.951. 0.95-1. p≤ (p≤0 PR=1 (PR= 1.17- 1.141 1.14-1 1.61- 0.951 0.95-1 (p≤ PR= (PR 1.14- 0.95- (p

Abstract Silica is a versatile material employed in different applications fields including aerospace, especially for rocket engines thermal protections. It is known that particles diameter causes variations in the material properties, and the best-known methods for diameter determination in general consist of several steps in sample preparation such as drying, sieving and the determination of the refractive index according different methods. On the other hand, Fourier transform infrared spectroscopy techniques (FT-IR), in reflectance mode, related to the particle size, are less used for this type of determination. Moreover, methodologies in the near infrared region (NIR) are even less explored. Therefore, the aim of this paper is to present a FTIR methodology for diffuse reflectance (DRIFT) in the middle infrared region (MIR) and reflectance analysis in near infrared region (NIRA) for the determination of the particle diameter on silica samples. Both methodologies showed good results. As proven by a test sample analysis, NIRA methodology indicated better precision. Furthermore, considering small and intermediated particle sizes, a tendency towards smaller errors for the absorbance measurements of the samples was found, consistently with the available literature results.

Abstract The objective of this study was to evaluate the in vitro effects, including surface morphological characteristics and chemical elemental properties, of different mouthwash formulations on enamel and dental restorative materials, simulating up to 6 months of daily use. Human enamel samples, hydroxyapatite, composite resin, and ceramic surfaces were exposed to 3 different mouthwashes according to label directions — Listerine® Cool Mint®, Listerine® Total Care, and Listerine® Whitening — versus control (hydroalcohol solution) to simulate daily use for up to 6 months. The samples were analyzed using scanning electron microscopy (SEM), infrared spectrophotometry (µ-Fourier transform infrared microscopy), energy-dispersive X-ray (EDX) spectroscopy, and color analysis before and after exposure. No relevant changes were observed in the morphological characteristics of the surfaces using SEM techniques. The physical and chemical aspects of the enamel surfaces were evaluated using mid-infrared spectroscopy, and EDX fluorescence was used to evaluate the elemental aspects of each surface. There was no variation in the relative concentrations of calcium and phosphorus in enamel, silicon and barium in composite resin, and silicon and aluminum in the ceramic material before and after treatment. No relevant changes were detected in the biochemical and color properties of any specimen, except with Listerine® Whitening mouthwash, which demonstrated a whitening effect on enamel surfaces. Long-term exposure to low pH, alcohol-containing, and peroxide-containing mouthwash formulations caused no ultra-structural or chemical elemental changes in human enamel or dental restorative materials in vitro.