The luminescence spectra and extended x-ray-absorption fine-structure ͑EXAFS͒ measurements of a series of Eu 3ϩ -based organic/inorganic xerogels were reported and related to the local coordination of the lanthanide cations. The hybrid matrix of these organically modified silicates, classed as U (2000) ureasils, is a siliceous network to which short organic chains containing oxyethylene units are covalently grafted by means of urea bridges. The luminescent centers were incorporated as europium triflate, Eu͑CF 3 SO 3 ͒ 3 , and europium bromide, EuBr 3 , with concentrations 200уnу20 and nϭ80, 40, and 30, respectively-where n is the number of ether oxygens in the polymer chains per Eu 3ϩ cation. EXAFS measurements were carried out in some of the U (2000) n Eu͑CF 3 SO 3 ͒ 3 xerogels ͑nϭ200, 80, 60, and 40͒. The obtained coordination numbers N ranging from 12.8, nϭ200, to 9.7, nϭ40, whereas the average Eu 3ϩ first neighbors distance R is 2.48-2.49 Å. The emission spectra of these multiwavelength phosphors superpose a broad green-blue band to a series of yellow-red narrow 5 D 0 → 7 F 0 -4 Eu 3ϩ lines and to the eye the hybrids appeared to be white, even at room temperature. The ability to tune the emission of the xerogels to colors across the chromaticity diagram is achieved by changing the excitation wavelength and the amount of salt incorporated in the hybrid host. The local environment of Eu 3ϩ is described as a continuous distribution of closely similar low-symmetry network sites. The cations are coordinated by the carbonyl groups of the urea moieties, water molecules, and, for U (2000) n Eu͑CF 3 SO 3 ͒ 3 , by the SO 3 end groups of the triflate anions. No spectral evidences have been found for the coordination by the ether oxygens of the polyether chains. A mean radius for the first coordination shell of Eu 3ϩ is calculated on the basis of the emission energy assignments. The results obtained for U (2000) n Eu͑CF 3 SO 3 ͒ 3 , 2.4 Å for 90 уnу40 and 2.6 and 2.5 Å for nϭ30 and 20, respectively, are in good agreement with the values calculated from EXAFS measurements. The energy of the intraconfigurational charge-transfer transitions, the redshift of the 5 D 0 → 7 F 0 line, with respect to the value calculated for gaseous Eu 3ϩ , and the hypersensitive ratio between the 5 D 0 → 7 F 2 and 5 D 0 → 7 F 1 transitions, point out a rather low covalency nature of the Eu 3ϩ first coordination shell in these xerogels, comparing to the case of analogous polymer electrolytes modified by europium bromide. ͓S0163-1829͑99͒03138-0͔

White light was produced exploiting an additive synthesis of red, green, and blue fluorescence through frequency upconversion in fluorolead-germanate glass codoped with Ho3+, Tm3+, and Yb3+. The 475, 540, and 650nm signals were, respectively, assigned to thulium (G41-H63) and holmium (S25;F45)→I85 and F55→I85, excited via energy tranfer from ytterbium. The dopant concentrations were adjusted, yielding the emission of a wide color gamut in the visible spectrum and the production of white light using excitation at 975nm. The spectral positions and purity (blue, 97%; green, 100%; red, 95%) of the three colors produced CIE-X=0.3438 and CIE-Y=0.3639 coordinates.

Chiroptera are one of the most diverse orders of mammals and a unique group within Mammalia that posses a wide geographic distribution and considerable variability in reproductive strategies. The aims of the present study were to characterise the male prostatic complex of the bat Myotis nigricans (Vespertilionidae) and evaluate seasonal variations in the prostatic complex of M. nigricans specifically. Twenty-three sexually mature specimens (four sample groups: winter, spring, summer and autumn) were subjected to macroscopic, microscopic, morphometric and ultrastructural analyses. The reproductive accessory glands of M. nigricans were found to be composed of a multilobed complex associated with the urethra and a pair of inguinal bulbourethral glands. The complex was composed of three bilobed prostatic regions (ventral, dorsolateral and dorsal) with no ampullary gland and seminal vesicles. This pattern of lobulation is very similar to that described for the prostate of rodents; however, it differs from that of other mammals and even other families of bats (e.g. Phyllostomidae and Molossidae). Each prostatic region in M. nigricans has unique and distinctive characteristics, which synchronise to establish the main reproductive peak of the species in summer. The data also indicated an asynchrony in the activity of primary and secondary reproductive organs in the annual reproductive cycle of M. nigricans in São Paulo State, Brazil.

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This paper describes the preparation and characterization of alginate beads coated with gelatin and containing Lactobacillus rhamnosus. Capsules were obtained by extrusion method using CaCl 2 as cross linker. An experimental design was performed using alginate and gelatin concentrations as the variables investigated, while the response variable was the concentration of viable cells. Beads were characterized in terms of size, morphology, scanning electron microscopy (SEM), moisture content, Fourier Transform Infrared Spectrometry (FTIR), thermal behavior and cell viability during storage. The results showed that the highest concentration of viable cells (4.2 x 10 9 CFU/g) was obtained for 1 % w/v of alginate and 0.1 % w/v of gelatin. Capsules were predominantly spherical with a rough surface, a narrow size distribution ranging from 1.53 to 1.90 mm and a moisture content of 97.70 ± 0.03 %. Furthermore, FTIR and thermogravimetric analysis indicated an interaction between alginate-gelatin. Cell concentration of alginate/gelatin microcapsules was 10 5 CFU/g after 4 months of storage at 8 o C.

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Glass structure and fluorine motion dynamics are investigated in lead-cadmium fluorgermanate glasses by means of differential scanning calorimetry, Raman scattering, x-ray absorption ͑EXAFS͒, electrical conductivity ͑EC͒, and 19 F nuclear magnetic resonance ͑NMR͒ techniques. Glasses with composition 60PbGeO 3 -xPbF 2 -yCdF 2 ͑in mol %͒, with xϩyϭ40 and xϭ10, 20, 30, 40, are studied. Addition of metal fluorides to the base PbGeO 3 glass leads to a decrease of the glass transition temperature (T g ) and to an enhancement of the ionic conductivity properties. Raman and EXAFS data analysis suggest that metagermanate chains form the basic structural feature of these glasses. The NMR study leads to the conclusion that the F-F distances are similar to those found in pure crystalline phases. Experimental results suggest the existence of a heterogeneous glass structure at the molecular scale, which can be described by fluorine rich regions permeating the metagermanate chains. The temperature dependence of the NMR line shapes and relaxation times exhibits the qualitative and quantitative features associated with the high fluorine mobility in these systems.