Exploring the potential of cryo-FESEM for the taxonomic study of aquatic microcrustaceans: Bathynellacea (Crustacea, Malacostraca) as an example.

The taxonomic study of microcrustaceans is a time consuming and challenging endeavor, which has slowed the rate of new discoveries, and in turn knowledge on, global aquatic biodiversity. To facilitate the study of these small organisms, new applications continually need to be explored. Here, we assess the potential use of environmental scanning electron microscopy (ESEM) techniques, specifically cryo-field emission SEM (cryo-FESEM), for taxonomic descriptions of microcrustaceans.

Non-destructive analyses on a meteorite fragment that fell in the Madrid city centre in 1896.

The historical Madrid meteorite chondrite fell in 1896 showing thin melt veins with a 65% of brecciated forsterite fragments surrounded by a fine grained matrix formed by troilite, chromite and Fe-Ni blebs. It exhibits a delicate iron infill, neo-formation of troilite in pockets and shock veins and neo-formation of Na-feldspar formed at high temperature and fast quenching. The semi-quantitative mineral determinations were performed with IMAGEJ freeware and chemical mappings resulting in the following approximated compositions: olivine (~55%); augite (~10%); enstatite (~10%); plagioclase (~10%); chromite (~2%); troilite (~4%), kamacite-taenite α-γ-(Fe, Ni) (~7%) and merrillite (~7%).

Study of coal and graphite specimens by means of Raman and cathodoluminescence.

The weak luminescence shown by coals has been attributed to accessorial minerals and poly-nuclear aromatic hydrocarbons, such as exinite, vitrinite or inertinite, while the luminescence quenching has been found in asphaltenes produced by coal hydrogenation or in pyridine extracts. Nowadays, the spatial resolution and the improved luminescence efficiency of the modern spectrometers allow some details of the luminescent emission centers to be explained. We have selected museum historical coal specimens with different rank, i.

Ossification vesicles with calcium phosphate in the eyes of the insect Copium teucrii (Hemiptera: Tingidae).

Arthropod eyes are built of repeating units named ommatidia. Each single ommatidium unit contains a cluster of photoreceptor cells surrounded by support cells and pigment cells. The insect Copium eye ommatidia include additional calcium-phosphate deposits, not described in insects to date, which can be examined today using a combined set of modern microscopy and spectroscopy techniques.

Influence of accumulation of heaps of steel slag on the environment: determination of heavy metals content in the soils.

The presence of high level of heavy metals involves a human healthy risk that could induce chronic diseases. This work reports on the metal contamination due to heaps of steel-slag accumulated during more than 40 years in allotments and industrial areas in the southern part of Madrid (Spain). Several slag and soil samples were collected in an area of 10 km(2) and characterized by different conventional (XRD and XRF) and no so common methods (ESEM, thermoluminescence and EDS-WDS).

Can luminescent Ru(II) polypyridyl dyes measure pH directly?

Two molecularly engineered Ru(II) complexes for direct pH optosensing in environmental or physiological media based on luminescence lifetime measurements-namely, Na(2)[Ru(bpds)(2)(F(15)ap)] and Na(2)[Ru(pbbs)(2)(pyim)] (where bpds = 2,2'-bipyridine-4,4'-disulfonate, F(15)ap = 5-perfluorooctanamide-1,10-phenanthroline, pbbs = 1,10-phenanthroline-4,7-(diyl)bis(benzenesulfonate), and pyim = 2-(2'-pyridyl)imidazole)-have been prepared. The suitability of these two luminophores as general-purpose pH indicators has been assessed to determine the general features of Ru(II) dyes required for such application. Their photochemical properties were investigated at different pH values in various buffer solutions using absorption spectroscopy, as well as steady-state and time-resolved luminescence.

Dynamical and structural changes of an anesthetic analogue in chemical and biological nanocavities.

We report on photophysical studies of the interaction between an anesthetic analogue, methyl 2-amino-4,5-dimethoxybenzoate (ADMB), with the human serum albumin (HSA) protein and the normal micelle of n-octyl-beta-D-glucopyranoside (OG) in water solutions. We used steady-state and picosecond time-resolved emission spectroscopy to follow the dynamical and structural changes due to their hydrophobicity and confinement on the photophysical behavior of ADMB. The formed 1:1 complex with the protein is robust with an equilibrium constant of 9.

Effect of nanocavity confinement on the relaxation of anesthetic analogues: relevance to encapsulated drug photochemistry.

We report on UV-vis absorption and picosecond emission studies of methyl 2-amino-4,5-dimethoxy benzoate in neutral water and complexed to alpha-, beta-, and gamma-cyclodextrin (CD). Upon encapsulation, the emission intensity and the fluorescence lifetime increase, indicating a hydrophobic effect of the nanocages on the photophysical behavior of the guest. beta-CD confinement shows the largest effect.

Femtochemistry of orange II in solution and in chemical and biological nanocavities.

In this work, we report on studies of the nature of the dynamics and hydrophobic binding in cyclodextrins and human serum albumin protein complexes with orange II. With femtosecond time resolution, we examined the proton-transfer and trans-cis isomerization reactions of the ligand in these nanocavities and in pure solvents. Because of confinement at the ground state, the orientational motion in the formed phototautomer is restricted, leading to a rich dynamics.