Spin-coated layers of ZnTPP have been used as optochemically interacting materials to detect 4-aminophenol, following the UV–vis optical absorption variations obtained by the exposure of the sensing ...layers to vapour analyte diluted in dry-air controlled atmosphere. A multichannel monitoring of the variation in the sensing layer main optical absorption bands after interaction with 4-aminophenol allow us to study the interaction mechanism between analyte and metalloporphyrin. Morphological characterization of the sensing layer was also performed by atomic force microscopy.
Poly(9,9-dioctylfluorene) (PFO) polymer films were deposited by matrix-assisted pulsed laser evaporation (MAPLE) technique. The polymer was diluted (0.5
wt%) in tetrahydrofuran and, once cooled to ...liquid nitrogen temperature, it was irradiated with a KrF excimer laser. 10,000 laser pulses were used to deposit PFO films on 〈1
0
0〉 Si substrates at different temperatures (−16, 30, 50 and 70
°C). One PFO film was deposited with 16,000 laser pulses at a substrate temperature of 50
°C. The morphology, optical and structural properties of the films were investigated by SEM, AFM, PL and FTIR spectroscopy. SEM inspection showed different characteristic features on the film surface, like deflated balloons, droplets and entangled polymer filaments. The roughness of the films was, at least partially, controlled by substrate heating, which however had the effect to reduce the deposition rate. The increase of the laser pulse number modified the target composition and increased the surface roughness. The angular distribution of the material ejected from the target confirmed the forward ejection of the target material. PFO films presented negligible modification of the chemical structure respect to the bulk material.
Surface plasmon resonance (SPR) imaging is a promising label free method that can be used in an array format for the detection of biomolecular interactions. In this work the DNA–DNA interaction was ...investigated. A DNA SH-oligonucleotide sequence was immobilized onto suitable photolithography patterned gold substrates and the hybridization reaction with the complementary strand was monitored by means of changes in the optical properties of the surface. The DNA probe used in this work was specific for the 35S promoter, a marker of the presence of genetically modified organisms (GMOs).
The effects of acute exposure to the herbicide terbuthylazine (3.55, 5.01 and 7.08
mg
l
−1) on the cells of farmed European sea bass,
Dicentrarchus labrax L., were investigated by means of light and ...electron microscopy. In gills of treated fish, the number of chloride cells (CCs) and rodlet cells (RCs) increased significantly within 24
h and 48
h, respectively; the intestine showed the largest increase in RCs linked to treatment and exposure time. In kidney, 24
h exposure induced a significant increase in RCs and the number and global area of macrophage aggregates (MAs).
Treated fish displayed cellular and/or ultrastructural alterations in all the organs examined. In the gills necrosis, lamellar and cellular oedema, epithelial lifting, telangectasia, and fusion of secondary lamellae were encountered. The liver presented myelin-like figures, cytoplasmic rarefaction and acute cell swelling of hepatocytes. In both organs, the severity of damage was dose–dependent.
In RCs of gills, the intestine and kidney of exposed sea bass, high cytoplasmic vacuolization, myelin-like figures, cristolysis and varying degrees of rodlet degeneration were observed. Extensive rodlet expulsion occurred in the gut lumen. Exposure to terbuthylazine also affected the renal tubular epithelial cells, which exhibited ‘blebs’. Damage to the intestinal epithelial cells was also observed.
Titanium dioxide (TiO
2
) nanorods in the brookite phase, with average dimensions of 3–4 nm × 20–50 nm, were synthesized by a wet-chemical aminolysis route and used as precursors for thin films that ...were deposited by the matrix-assisted pulsed laser evaporation (MAPLE) technique. A nanorod solution in toluene (0.016 wt% TiO
2
) was frozen at the liquid-nitrogen temperature and irradiated with a KrF excimer laser at a fluence of 350 mJ/cm
2
and repetition rate of 10 Hz. Single-crystal Si wafers, silica slides, carbon-coated Cu grids and alumina interdigitated slabs were used as substrates to allow performing different characterizations. Films fabricated with 6000 laser pulses had an average thickness of ∼150 nm, and a complete coverage of the selected substrate as achieved. High-resolution scanning and transmission electron microscopy investigations evidenced the formation of quite rough films incorporating individually distinguishable TiO
2
nanorods and crystalline spherical nanoparticles with an average diameter of ∼13 nm. Spectrophotometric analysis showed high transparency through the UV-Vis spectral range. Promising resistive sensing responses to 1 ppm of NO
2
mixed in dry air were obtained.
Surface plasmon resonance (SPR) has recently gained attention as a label-free method for the detection of biological molecules binding onto functionalised surfaces. It is one of the most sensitive ...detection method for monitor variations in the thickness and refractive index in ultra-thin films. Here, the adsorption processes of oligonucleotides onto gold substrates have been investigated in aqueous buffer solution using SPR imaging measurements. The hybridization of a thiol-modified, single stranded oligonucloetide anchored to a gold surface via thiol group, with its complementary sequence has been observed and characterised monitoring the hybridization process by SPR equipment. In situ investigation of smallest changes in SPR imaging measurements dynamically performed in liquid phase in the presence of DNA complementary probes was performed. Infrared spectroscopy and scanning electron microscopy characterisation of the functionalised gold surfaces of the biosensor were compared with the images obtained by SPR experimental apparatus.
We report morphological and optical properties of a colloidal TiO2 nanoparticle film, deposited on a quartz substrate by using the Matrix-Assisted Pulsed Laser Evaporation (MAPLE) technique. Atomic ...Force Microscopy demonstrated that a good uniformity of the deposition can be obtained. The presence of agglomerates with dimensions of about 1mum in size was noticed. Form UV-vis transmission spectra, recorded in the 200-800nm range, the optical constants and the energy gap were determined besides the film thickness. The optical constants resulted in agreement with the values reported in literature for TiO2 nanoparticle thin films.
Matrix-assisted pulsed laser evaporation (MAPLE) was used to deposit layers of poly(9,9-dioctylfluorene) (PFO) to study the relation between the solvent properties (laser light absorption, boiling ...temperature and solubility parameters) and the morphology of the deposited films. To this end, the polymer was diluted (0.5 wt%) in tetrahydrofuran—THF, toluene and toluene/hexane mixtures. The thickness of the films was equal to 70±20 nm. The morphology and uniformity of the films was investigated by Atomic Force Microscopy and by the photoluminescence emission properties of the polymer films, respectively. It is shown that, although the solubility parameters of the solvents are important in controlling the film roughness and morphology, the optical absorption properties and boiling temperature play a very important role, too. In fact, for matrices characterized by the same total solubility parameter, lower roughness values are obtained for films prepared using solvents with lower penetration depth of the laser radiation and higher boiling temperatures.
Spherical and rod shaped organic--capped TiO2 nanocrystals (NCs), prepared by a hydrolytic route, were deposited as thin films and characterized by means of atomic force microscopy (AFM), X--ray ...diffraction (XRD) and surface plasmon resonance (SPR). SPR was assessed as transduction technique in order to test the sensing ability of the prepared films for detection of alcohol vapours as a function of NC shape and thermal treatment. The performances of the TiO2 nanocrystals were found to be dependent on the titania nanocrystal morphology and thermal treatment conditions, pointing to the beneficial effect of a rod--like shape as compared to a spherical one, and to a possible role of the titania surface organic coating in enhancing the sensor response.
Robust measurements based on current large-scale structure surveys require precise knowledge of statistical and systematic errors. This can be obtained from large numbers of realistic mock galaxy ...catalogues that mimic the observed distribution of galaxies within the survey volume. To this end we present a fast, distributed-memory, planar-parallel code, l-picola, which can be used to generate and evolve a set of initial conditions into a dark matter field much faster than a full non-linear N-Body simulation. Additionally, l-picola has the ability to include primordial non-Gaussianity in the simulation and simulate the past lightcone at run-time, with optional replication of the simulation volume. Through comparisons to fully non-linear N-Body simulations we find that our code can reproduce the z=0 power spectrum and reduced bispectrum of dark matter to within 2% and 5% respectively on all scales of interest to measurements of Baryon Acoustic Oscillations and Redshift Space Distortions, but 3 orders of magnitude faster. The accuracy, speed and scalability of this code, alongside the additional features we have implemented, make it extremely useful for both current and next generation large-scale structure surveys. l-picola is publicly available at https://cullanhowlett.github.io/l-picola.
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