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ABSTRACT.We have been able to discriminate different castes and sexes of ants in the same colony by measuring cuticular hydrocarbon levels with Fourier transform infrared photoacoustic spectroscopy, compared by canonical discriminant function analysis. We have now applied this methodology to various colonies of two species of ants of the genus Ectatomma in the Brazilian Cerrado. There were clear interspecific differences in cuticular hydrocarbons of these ants, with a small intraspecific variation. The differences between colonies were greater in E. brunneum than in E. vizottoi. Genetic differences among the colonies and species were well estimated by Fourier transform infrared photoacoustic spectroscopy and statistical analyses.

Development of novel bioimaging materials that exhibit organelle specific accumulation continues to be at the forefront of research interests and efforts. Among the various subcellular organelles, mitochondria, which are found in the cytoplasm of eukaryotic cells, are of particular interest in relation to their vital function. To date, most molecular probes that target mitochondria utilise delocalised lipophilic cations such as triphenylphosphonium and pyridinium. However, the use of such charged motifs is known to be detrimental to the working function of the mitochondrial transmembrane potential and there remains a strong case for development of neutral mitochondrial fluorescent probes. Herein, we demonstrate for the first time the exploitation of diketopyrrolopyrrole‐based chemistries for the realisation of a neutral fluorescent probe that exhibits organelle specific accumulation within the mitochondria at the nanomolar level. The synthesised probe, which bears a neutral triphenylphosphine oxide moiety, exhibits a large Stokes shift and high fluorescence quantum yield in water, both highly sought‐after properties in the development of bioimaging agents. In vitro studies reveal no interference with cell metabolism when tested for the human MCF7 breast cancer cell and nanomolar subcellular organelle colocalisation with commercially available mitochondrial staining agent Mitotracker Red. In light of its novelty, neutral structure and the preferential accumulation at nanomolar concentrations we anticipate this work to be of significant interest for the increasingly larger community devoted to the realisation of neutral mitochondrial selective systems and more widely to those engaged in the rational development of superior organic architectures in the biological field.

In this study the relations among nonbridging oxygen ͑NBO͒, optical properties, optical basicity, and color center formation in CaO-MgO aluminosilicate glasses were studied. Samples containing ͑in mol %͒ 35.9-57.5 of CaO, 16-27.7 of Al 2 O 3 , 7.9-41.6 of SiO 2 , and 6.5-6.9 of MgO were measured by optical absorption and excitation, luminescence, and Raman spectroscopy. The results showed that when the SiO 2 content was increased, the absorption edge shifted toward lower wavelengths and the bonds between O 2− ions and cations became more covalent. These observations were confirmed by Raman results that showed a decrease in the number of NBO per silicon tetrahedron as a function of SiO 2 content. The results indicate that the effects of higher NBO concentration are the narrowing of the band gap energy and the delocalization of O 2− electrons, which facilitates the O 2− electrons to be trapped by anion vacancies and, consequently, forming color centers. The relationship between color center formation and SiO 2 content was confirmed by optical spectroscopic measurements under UV radiation.

Site-selective laser excitation and luminescence measurements at 15 K of CaMoO4 single crystal doped with Nd3+ and co-doped with Nb5+ charge compensator have been investigated in the spectral region of laser interest involving the transition. A larger than expected number of Nd3+ sites was found and a model to explain this result is presented. A partial diagram of 4F3/2 and 4I11/2 levels was constructed from the acquired data and their features are discussed.

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