A new tetrakis β-diketone ligand for NIR emitting LnIII ions: luminescent doped PMMA films and flexible resins for advanced photonic applications

A new antenna molecule containing four benzoyltrifluoroacetone (BTFA) moieties anchored to a single carbon atom and connected through four flexible methoxy groups, namely 1,1'-(4,4'-(2,2-bis((4-(4,4,4-trifluoro-3-oxobutanoyl)phenoxy)methyl) propane-1,3-diyl)bis(oxy)bis(4,1-phenylene))bis(4,4,4-trifluorobutane-1,3-dione) [H4L], has been designed and synthesized. Using this ligand, a series of homo- and hetero-metallic Ln(III) complexes of general formula [LnL]NBu4 (where Ln = Sm (1), Gd (2), Er (3), Yb (4), Er0.5Yb0.5 (5), Er0.5Gd0.5 (6), Yb0.5Gd0.5 (7) and NBu4 = tetrabutyl ammonium) have been isolated. All these complexes have high molar absorption coefficients (>40 000 M-1 cm(-1) around 330 nm in DMF) and display strong visible (Sm-III) and/or, NIR (Sm-III, Er-III, Yb-III) luminescence in solid state and in DMF solution upon irradiation at the ligand-centred bands in the range 250-400 nm. Furthermore, these complexes have been doped into PMMA matrices yielding highly luminescent, photo-stable films and flexible resins made of fibres with average diameter 300-400 nm. Photoluminescence studies show that the newly designed ligand is an adequate sensitizer for Sm-III, Yb-III and Er-III luminescence. The emission quantum yields and the luminescence lifetimes at room-temperature are 3.4 +/- 0.5% and 79.1 +/- 1 mu s for Sm-III and 2.6 +/- 0.4% and 12.1 +/- 0.1 mu s for Yb-III in solid state. Furthermore the overall quantum yields and lifetime measurements for the mixed metallic complex show that Yb-III -> Er-III energy transfer occurs resulting in enhanced Er-III emission

Conjunctival bacterial and fungal flora in clinically normal sheep.

ABSTRACT Objectives: The aim was to identify conjunctival bacterial and fungal flora in clinically normal sheep. Design: Prospective study. Setting: Tuscany. Participants: 100 eyes from 50 adult Massese female sheep were examined. The sheep included in the study were considered free of anterior ophthalmic abnormalities. Primary and secondary outcome measures: Bacteria were identified by morphological assessment, Gram staining, biochemical tests. Identification of filamentous fungi was achieved at the genus level, and Aspergillus species were identified based on keys provided by other authors. Yeast colonies were highlighted, but not identified. Results: Positive cultures were obtained from 100/100 eyes for bacteria, and from 86/100 eyes for fungi. A total of 14 types of bacteria and 5 types of fungi were isolated. Yeasts were isolated from 13/100 eyes. The most frequent fungal isolates were saprophytic fungi. Conclusions: Conjunctival bacterial and fungal flora of clinically normal eyes were reported in sheep. The positivity obtained for conjunctival bacteria was higher compared to findings in the literature by other authors in the same species (100 per cent v 40 per cent), while our results were in line with a recent work performed on mouflons (Ovis Musimon) with a 100 per cent positivity for bacterial conjunctival fornix. In our survey, Gram-positive species were prevalent, as reported by other authors in different species. Few data are available in the literature regarding conjunctival fungal flora in healthy small ruminants. The prevalence of conjunctival fungal flora in this study was higher than findings reported in mouflons (86 per cent v 45 per cent). Differences in fungal prevalence may be due to different methods of managing herds, though further studies are required to verify this hypothesis. The similarities in bacterial and fungal isolates between sheep and mouflons suggest a genera pattern of conjunctival colonisation by bacteria and fungi

Dissemination of wine-related yeasts by migratory birds.

The present work was undertaken to evaluate the con-tribution of migratory birds in the environmental dis-semination of yeasts. Four sites (Mazara del Vallo,Lampedusa, Ustica and Linosa), representing themain stop-over points in Sicily, were analysed duringspring and autumnal bird migration and 349 birds(belonging to 10 families) were ringed and analysedfor yeast presence. A total of 125 yeasts were isolated and identified by a multiple genotypic approach, con-sisting of restriction fragment length polymorphism(RFLP) of 5.8S rRNA gene and 26S rRNA andsequencing of D1/D2 domain of the 26S rRNA gene,which resulted in the recognition of 18 species,including the technological relevantSaccharomycescerevisiaewhich were characterized at strain levelapplying three techniques (interdelta analysis, mini-satellite analysis based on the separate amplificationof three genes and microsatellite multiplex PCR ofpolymorphic microsatellite loci). The evaluation of thepersistence of livingS. cerevisiae in birds for about12 h from ingestion of inoculated feed allowed theconclusion that yeasts with technological potentialare disseminated during migration

Diversity of Staphylococcus aureus Isolates in European Wildlife

Staphylococcus aureus is a well-known colonizer and cause of infection among animals and it has been described from numerous domestic and wild animal species. The aim of the present study was to investigate the molecular epidemiology of S. aureus in a convenience sample of European wildlife and to review what previously has been observed in the subject field. 124 S. aureus isolates were collected from wildlife in Germany, Austria and Sweden; they were characterized by DNA microarray hybridization and, for isolates with novel hybridization patterns, by multilocus sequence typing (MLST). The isolates were assigned to 29 clonal complexes and singleton sequence types (CC1, CC5, CC6, CC7, CC8, CC9, CC12, CC15, CC22, CC25, CC30, CC49, CC59, CC88, CC97, CC130, CC133, CC398, ST425, CC599, CC692, CC707, ST890, CC1956, ST2425, CC2671, ST2691, CC2767 and ST2963), some of which (ST2425, ST2691, ST2963) were not described previously. Resistance rates in wildlife strains were rather low and mecA-MRSA isolates were rare (n = 6). mecC-MRSA (n = 8) were identified from a fox, a fallow deer, hares and hedgehogs. The common cattle- associated lineages CC479 and CC705 were not detected in wildlife in the present study while, in contrast, a third common cattle lineage, CC97, was found to be common among cervids. No Staphylococcus argenteus or Staphylococcus schweitzeri-like isolates were found. Systematic studies are required to monitor the possible transmission of human- and livestock- associated S. aureus/MRSA to wildlife and vice versa as well as the possible transmission, by unprotected contact to animals. The prevalence of S. aureus/MRSA in wildlife as well as its population structures in different wildlife host species warrants further investigation

Recent Advances in Lanthanide Based Nano-Architectures as Probes for Ultra High-Field Magnetic Resonance Imaging

Paramagnetic Lanthanide ions incorporated into nano- architectures are emerging as a versatile platform for Magnetic Resonance Imaging (MRI) contrast agents due to their strong contrast enhancement effects combined with the platform capability to include multiple imaging modalities. This short review examines the application of lanthanide based nanoarchitectures (nanoparticles and nano- assemblies) in the development of multifunctional probes for single and multimodal imaging involving high field MRI as one imaging modality.status: publishe

High-Field MRI Contrast Agents and their Synergy with Optical Imaging: the Evolution from Single Molecule Probes towards Nano-architectures

Contrast agents for magnetic resonance imaging have historically been based on paramagnetic metal complexes, particularly Gd3+ chelates, which tend to lose their contrast enhancement ability with increasing magnetic field strength. Emerging high-field MRI applications require the development of novel contrast agents that exhibit high relaxation enhancement as a function of magnetic field strength. Paramagnetic ions such as Dy3+ , Tb3+ or Ho3+ incorporated into supramolecular or inorganic nano-architectures represent promising platforms for the development of high field MRI contrast agents. Furthermore, such platforms allow facile inclusion of multiple imaging modalities, therapeutic loading, and targeting vectors. This Minireview examines the application of contrast agents for high-field MRI, which range from single molecules to nanoparticles. Approaches to create multimodal agents by combining high-field MRI contrast properties with another imaging modality are also discussed.status: publishe

Antimicrobial resistance and minimum inhibitory concentrations of bacteria isolated from bustards in the United Arab Emirates

The resistance to 11 antimicrobial agents of bacteria isolated from clinical and postmortem cases of five species of bustards maintained in captivity in the United Arab Emirates (UAE) from 1995 to 1997 was determined by disc sensitivity. Of 226 isolates, 169 (74.8%) were gram-negative bacilli, with the majority identified as Escherichia coli (28.8%) and Pseudomonas aeruginosa (19%). The isolates of E. coli showed a high prevalence of resistance to amoxycillin (69%), tetracycline (66.7%), and sulphamethoxazole (43.3%). Moderate resistance to enrofloxacin was observed in E. coli (30%) and P. aeruginosa (13%) isolates. The minimum inhibitory concentrations (MICs) to seven antimicrobial agents were determined for 133 bacterial isolates from bustards during 1996 to 1997. Enrofloxacin (concentration required to inhibit 50% of the isolates [MIC50] < 0.5 mu g/ml) and gentamicin (MIC50 less than or equal to 1.0 mu g/ml) exhibited good activity against both gram-negative bacilli and staphylococci isolated from bustards. Enrofloxacin (MIC50 less than or equal to 1.5 mu g/ml), gentamicin (MIC50 less than or equal to 2.0 mu g/ ml), and piperacillin (MIC50 less than or equal to 4.0 mu g/ml) exhibited good activity against P. aeruginosa isolates. Amoxycillin/clavulanic acid showed good activity (concentration required to inhibit 90% of the isolates [MIC50] less than or equal to 2.0 mu g/ml) against gram-positive cocci and moderate activity (MIC50 less than or equal to 3.0 mu g/ml) against E. coli, Salmonella spp., and Klebsiella spp. Amoxycillin exhibited good activity (MIC50 less than or equal to 0.5 mu g/ml) against gram-positive organisms and moderate activity (MIC50 less than or equal to 1.0 mu g/ml) against Salmonella spp. These results provide information on the prevalence of resistant bacterial strains and the MICs of organisms derived From bustards in the UAE

Synthesis, Structure and Optical Studies of a Family of Three-Dimensional Rare-Earth Aminoisophthalates M(mu(2)-OH)(C8H5NO4)] (M = Y3+, La3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Dy3+, and Er3+)

A hydrothermal reaction of the acetate salts of the rare-earths, 5-aminoisophthalic acid (H(2)AIP), and NaOH at 150 degrees C for 3 days gave rise to a new family of three-dimensional rare-earth aminoisophthalates, M(mu(2)-OH)(C8H5NO4)] M = Y3+ (I), La3+ (II), Pr3+ (III), Nd3+ (IV), Sm3+ (V), Eu3+ (VI), Gd3+ (VII), Dy3+ (VIII), and Er3+ (IX)]. The structures contain M-O(H)-M chains connected by AIP anions. The AIP ions are connected to five metal centers and each metal center is connected with five AIP anions giving rise to a unique (5,5) net. To the best of our knowledge, this is the first observation of a (5,5) net in metal-organic frameworks that involve rare-earth elements. The doping of Eu3+/(3+) ions in place of Y3+/ La3+ in the parent structures gave rise to characteristic metal-centered emission (red = Eu3+, green = Tb3+). Life-time studies indicated that the excited emission states in the case of Eu3+ (4 mol-% doped) are in the range 0.287-0.490 ms and for Tb3+ (4 mol-% doped) are in the range of 1.265-1.702 ms. The Nd3+-containing compound exhibits up-conversion behavior based on two-photon absorption when excited using lambda = 580 nm