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Triclosan is used in hygiene products and cosmetics, due to its antimicrobial action. The emergence of the Covid-19 pandemic at the beginning of 2020, there was an increase in the consumption of products composite also with TCS, such as hand antiseptics, alcohol gel and liquid soap, which means a risk of streams contamination higher. In this work, a new carbon-based voltammetric sensor modified with multi-walled carbon nanotubes (MWCNT) decorated with Eu 2 O 3 nanoparticles, was developed to quantify TCS in water samples. Based on the electrochemical reaction of the TCS in the electro active area of the sensor, an analytical curve was obtained using the sensor with best analytical performance, it was successfully applied to assess the presence of TCS in water samples. By the results it can be noted an increase in the electrochemical area of the modified sensor and a decrease in the resistance to charge transfer, providing an increase in the sensitivity of the developed sensor, which proved to be very selective, accurate and easy to reproduce. The results show that the proposed voltammetric sensor has excellent catalytic activity with a wide detection range (3.8 × 10−7 and 1.8 × 10−5 mol L−1), and an ultrasensitive limit of detection (LOQ) and quantification (LOQ) (2.3 × 10−9 and 7.6 × 10−9 mol L−1, respectively). The proposed sensor was applied to determine TCS in groundwater and river. The recovery rates obtained were 97.5–102.2% for previously contaminated water samples. The results allow us to conclude that the developed sensor presents itself as an option for TCS detection. [Display omitted] • A new nanocomposite based on MWCNT and Eu 2 O 3 was developed. • Triclosan pose a risk to the health of living beings such as humans, animals, and to the environment. • A fast, inexpensive and sensitive sensor was developed to determine Triclosan. • The proposed method was successfully validated, showing excellent recovery rates. [ABSTRACT FROM AUTHOR]

Abstract The use of silver nanoparticles (AgNPs) in commercial products has increased significantly in recent years. However, findings on the toxic effects of the AgNPs are still limited. This paper reports an investigation on the cytotoxic and genotoxic potential of the AgNPs on root cells of Allium cepa. Germination (GI), root elongation (REI), mitotic (MI), nuclear abnormality (NAI), and micronucleus index (MNI) were determined for seeds exposed to various AgNPs diameters (10, 20, 51, and 73 nm) as well as to the silver bulk (AgBulk) (micrometer-size particles) at the concentration of 100 mg·L−1. Transmission electron microscopy (TEM) provided the particle size distribution, while dynamic light scattering (DLS) was used to get the hydrodynamic size, polydispersity index, and zeta potential of the AgNPs. Laser-induced breakdown spectroscopy (LIBS) and inductively coupled plasma/optical emission spectrometry (ICP OES) were applied for quantifying the AgNPs content uptake by roots. Silver dissolution was determined by dialysis experiment. Results showed that the AgNPs penetrated the roots, affecting MI, GI, NAI, and MNI in meristematic cells. Changes in these indicators were AgNPs diameter-dependent so that cytotoxic and genotoxic effects in Allium cepa increased with the reduction of the particle diameter. The results also revealed that the AgNPs were the main responsible for the cytotoxicity and genotoxicity since negligible silver dissolution was observed. Graphical abstract Unlabelled Image Highlights • Allium cepa seeds were exposed to different AgNPs dimensions (10, 20, 51, and 73 nm) • Cytotoxic and genotoxic effects of the AgNPs on root cells of the A. cepa were tested. • AgNPs were able to penetrate in plant cell and cause cell toxicity. • Cytotoxic and genotoxic effects increased with decreasing AgNPs diameter. • AgNPs were the main responsible for the toxicity. [ABSTRACT FROM AUTHOR]

Very few devices are capable to measure temperature with high precision and sensitive, mainly in the micro and nanoscale. It is known that for biological applications it is required high sensitivity devices in a short temperature range (288–323 K). Recent reports are proposing the use of ratiometric thermometers based in the luminescence of trivalent lanthanide ions. In this paper, the ratiometric thermometer characteristic was investigated in an alumino-phosphate glass doped with Eu 2 O 3 . The studied temperature range was 288 – 333 K, and the material presents high sensitivity values (1.25–1.68% per K). The luminescence of Eu 3+ -doped alumino-phosphate glass does no present losses by energy transfer mechanism in this temperature range, making a quick predicable thermometric parameter by use of ratio between the integrated intensities of 5 D 0 → 7 F 2 and 5 D 0 → 7 F 0 transitions, respectively. Both excitation and emission are in wavelengths not strongly absorbed by living tissues, becoming promising material to applications in the laboratories scale, as the temperature measurements of cell cultures, and monitoring of tissues that does not require high penetration of excitation wavelengths. [ABSTRACT FROM AUTHOR]

The aim of this study was to explore whether the nest chemical profile (NCP) can be used to determine intra- and interspecific differences in social wasps of the subfamily Polistinae. For this purpose, Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) was used to directly analyze small pieces of nest as well as the gasters of females. An advantage of the methodology was that no sample preparation was required. FTIR-PAS combined with multivariate discriminant analyzes was used, to the best of our knowledge for the first time, to evaluate the NCPs of six species of polistine wasps, observing the influence of the nesting environment and investigating the relationships among the nest and female cuticular chemical profiles. The results revealed significant inter-species differences among the NCPs, as well as strong correlations with the environments in which the nests were located. The Mischocyttarus and Polistes species belong to the same tribe (Polistini) and therefore exhibited similar NCPs. These species were separated from the Polybia species in the NCP dendrogram, mainly because the Polybia belong to another tribe (Epiponini). Correlation was observed between the NCPs and the cuticular chemical profiles of females. The findings of the study demonstrated the importance of the NCP for differentiation of species and environments, and the utility of FTIR-PAS for identification of correlations between individuals and nests. The results confirmed the hypothesis that the NCP can be used as an additional tool for intra- and interspecific differentiation in social wasps of the subfamily Polistinae. [ABSTRACT FROM AUTHOR]

The cooling efficiency for optical refrigeration by anti-Stokes Fluorescence was measured in a 10% Yb3+:LiYF 4 crystal by Differential Luminescence Thermometry (DLT) and Thermal Lens Spectroscopy (TLS) over a range of pump intensities. Results showed that background and coolant ion absorption coefficients saturated at low intensities, and saturated differently as a function of wavelength. For wavelengths longer than 1000 nm, a higher pump intensity led to improved cooling efficiency through a differential saturation phenomenon. In this range, background absorption saturated more easily than the absorption of coolant ions so that parasitic heating was diminished, yielding higher cooling efficiency for higher pump intensities. This saturation phenomenon therefore offers the prospect of improved performance of electronic devices such as imaging arrays in space which could operate with reduced noise at low temperatures through laser cooling. The measured cooling efficiency was independent of pump intensity at a wavelength of 1000 nm where the saturation intensity of background absorption was found to be the same as that of Ytterbium in LiYF 4. A novel experimental method for determining the saturation intensities of impurity and coolant ions is described, and consequences for laser cooling and radiation-balanced laser operation of the observed saturation effects are discussed and analyzed. • Saturation of the background impurity absorption in laser cooling of solids is observed experimentally for the first time. • An original method is reported to determine the saturation intensity of background absorption. • Improvements for both laser cooling of solids and Radiation-Balanced lasers are discussed. [ABSTRACT FROM AUTHOR]

Insects can provide clues in a variety of ways to assist in criminal investigations. The FTIR-PAS technique has been successfully used to assess the cuticular chemical profiles of insect samples from different groups and for several goals. However, until now, it has never been used to evaluate samples of forensic interest, despite providing faster results, compared to the methods currently used. In this study, mid-infrared photoacoustic spectroscopy was employed to assess the cuticular chemical profiles of different stages of development of the blow fly Chrysomya megacephala sampled from two distinct populations. The results showed that this technique enabled detection of significant differences between the main vibrational modes of the chemical bonds present in the cuticles of the two populations and the different stages of development of the fly. The method enables identification of the age of individuals collected at the crime scene, as well as the distinction of different populations. Therefore, this methodology could assist in forensic investigations, in both estimating the Postmortem Interval and determining the location where the crime occurred, or whether the body had suffered some type of translocation. The technique provides high reproducibility and fast analysis, so its application for analysis of C. megacephala is a viable option in forensic crime investigations. • Cuticular chemical profile of stages of development of the Chrysomya megacephala. • Mid-infrared photoacoustic spectroscopy in analysis of forensic importance. • Variation of cuticular chemical profile of population of the Chrysomya megacephala. [ABSTRACT FROM AUTHOR]