Luminescent Properties of β-(hydroxyaryl)-butenolides and Fluorescence Quenching in Water.

This work describes the luminescent properties of the new compound β-(hydroxyaryl)-butenolides recently discovered. The compounds were subjected to UV-Vis absorption and fluorescence analyzes when diluted in different solvents. Through the results, it was possible to observe that the β-hydroxyarylutenolides have two absorption bands, one at 289-291 nm and the other with higher intensity at 328-354 nm.

Assessing the Fate of Superparamagnetic Iron Oxide Nanoparticles Carrying Usnic Acid as Chemical Cargo on the Soil Microbial Community.

In the present study we evaluate the effect of superparamagnetic iron oxide nanoparticles (SPIONs) carrying usnic acid (UA) as chemical cargo on the soil microbial community in a dystrophic red latosol (oxysol). Herein, 500 ppm UA or SPIONs-framework carrying UA were diluted in sterile ultrapure deionized water and applied by hand sprayer on the top of the soil. The experiment was conducted in a growth chamber at 25 °C, with a relative humidity of 80% and a 16 h/8 h light-dark cycle (600 lx light intensity) for 30 days.

Use of fish scales in environmental monitoring by the application of Laser-Induced Breakdown Spectroscopy (LIBS).

The objective of this study was to evaluate the efficiency of Laser-Induced Breakdown Spectroscopy (LIBS) to detect the presence of bioaccumulated Fe and Pb in scales of Salminus brasiliensis and Prochilodus lineatus, and to compare the results from this technique with those obtained using the conventional atomic absorption spectrometry technique. The study used fish collected in the Amambai River, Upper Paraná River, Brazil. The LIBS technique detected the presence of Fe in S.

Decontamination and disinfection of wastewater by photocatalysis under UV/visible light using nano-catalysts based on Ca-doped ZnO.

Nano-catalysts based on ZnO-Ca x% (with x = 0, 0.1, 0.3, 0.

Use of Fourier transform infrared spectroscopy to monitor sugars in the beer mashing process.

Mashing is an enzymatic procedure for the extraction of sugars from malt. It has strong temperature dependence, so monitoring the sugar production is very important for optimization of the brewing process. In this work, Fourier transform infrared spectroscopy (FTIR) was used to monitor three different mashing programs.

Intraspecific variation and influence of diet on the venom chemical profile of the Ectatomma brunneum Smith (Formicidae) ant evaluated by photoacoustic spectroscopy.

Studies of venomous animals have shown that environmental and genetic factors contribute to determining the chemical composition of venom. It is well known that external effects cause differences in the toxicity, concentration, and prey specificity of venom. However, the influence of different factors on the chemical profile of Hymenoptera venom remains little explored.

Laser-induced fluorescence in fish scales to evaluate the environmental integrity of ecosystems.

The aim of this study was to evaluate the fluorescence of Astyanax lacustris fish scales when excited in the UV-A and blue regions for use as a bioindicator of aquatic ecosystems. This species was firstly defined as Astyanax altiparanae, popularly known as "lambari-do-rabo-amarelo". Currently, abiotic/biotic environmental integrity is generally assessed using limnological and physicochemical parameters related to biological indicators in streams or rivers, which are not sufficient to evaluate the real environmental conditions: in some cases, these parameters can be strongly dependent on local weather conditions.

Morphophysiological and cuticular chemical alterations caused by Xenos entomophagus endoparasites in the social wasp Polistes ferreri (Hymenoptera, Vespidae).

Social wasps can face many challenges during their colony cycle, including the presence of parasites. The order Strepsiptera is among the main parasites of the wasp genus Polistes. The aim of this study was to evaluate the effect of an endoparasite species on the host Polistes ferreri, with the hypothesis that females of this social wasp would undergo morphophysiological alterations as well as changes in their cuticular chemical profile caused by the obligate endoparasite.

High Surface-Enhanced Raman Scattering (SERS) Amplification Factor Obtained with Silver Printed Circuit Boards and the Influence of Phenolic Resins for the Characterization of the Pesticide Thiram.

In this work, low-cost substrates with rough silver surfaces were prepared from commercial copper foil-covered phenolic board (CPB) and an aqueous solution of AgNO3, and were used for surface-enhanced Raman scattering (SERS) and surface-enhanced resonance Raman scattering (SERRS) measurements. A maximum SERS amplification factor of 1.2 × 10(7) was obtained for Rhodamine 6G (R6G), and use of the CPB resulted in a detection limit for Thiram pesticide of 0.

Chemical signals might mediate interactions between females and juveniles of Latrodectus geometricus (Araneae: Theridiidae).

Studies related to communication on spiders show that, as in other invertebrates, the interactions between conspecifics are also made through chemical signals. Therefore, in order to assess whether the composition of cuticular compounds might be involved in interactions that occur during the days after the emergence of juveniles in Latrodectus geometricus, we conducted behavioral and cuticular chemical profiles analysis of females and juveniles of different ages. The results show that females, regardless of their reproductive state, tolerate juveniles of other females with up to 40 days post-emergence and attack juveniles of 80 days post-emergence.

Broad combined orange-red emissions from Eu²⁺- and Eu³⁺-doped low-silica calcium aluminosilicate glass.

In this paper, a broad combined orange-red emission from Eu²⁺- and Eu³⁺-doped low-silica calcium aluminosilicate (LSCAS) glass is reported. Spectroscopic results demonstrate that it is possible to tune the emission wavelength by changing the excitation wavelength in the UV-Vis region. The color coordinates for the emission spectra were calculated, and using the Commission Internationale de l'Éclairage 1931 and 1976 chromatic diagrams, it is possible to note that they are dependent on the excitation wavelength.

Angular dependence of the thermal-lens effect on LiSrAlF6 and LiSrGaF6 single crystals.

We apply thermal-lens (TL) spectrometry to measure the angular dependence of the TL effect on colquiriite single crystals. The experiments were performed with LiSrAlF(6) and LiSrGaF(6) using a two-beam mode-mismatched configuration. The results show that it is possible to minimize the TL effect by selecting the appropriate crystal orientation.