Oligo(poly)thiophenes were investigated by photoelectrochemical methods as monolayer sensitizers of CdSe nanocrystal (CdSe-NCs) and TiO2 polycrystalline films on ITO electrodes. 7.5 nm diameter ...CdSe-NCs layers and polycrystalline (anatase, ca. 40 nm crystallite size) TiO2 films were functionalized with an α,ω-dicarboxylic sexithiophene and with two polythiophenes, bearing differently spaced side carboxylic terminals, including regioregular poly(thiophene-3-propionic acid). The modified electrodes were investigated in a three-electrode photoelectrochemical cell in the presence of iodide as sacrificial generator of intense and steady oxidative photocurrents. The oligo(poly)thiophenes act in general as moderate hypersensitizers (roughly twice more efficient than calculated). Poly(thiophene-3-propionic acid) monolayers, formed on CdSe-NC structures from ethanol, generate a strong hypersensitization, i.e., a response 5 times higher than expected. From optical and photoluminescence analysis such a result is attributed to a flat disposition of the thiophene planes on the surface which allows a faster phototransport. CdSe-NC sensitization of the ITO and TiO2 surfaces is also reported in detail.
Anatase phase of titanium oxide is the most promising photocatalyst material for organic pollutant degradation. However, due to its large band gap energy (3.2
eV) it is not viable to use sunlight as ...an energy source for the photocatalysis activation, and so, ultraviolet (UV) radiation below the wavelength of 380
nm is required.
This paper focuses on the experimental demonstration of the reduction of this large band gap energy by inducing defects in the anatase structure under the form of oxygen sub-stoichiometry. TiO
2 thin films were prepared in a metal organic chemical vapour deposition (MOCVD) reactor. The samples stoichiometry was measured by the Rutherford backscattering spectrometry (RBS) technique. Optical characterisation was also performed and the photodegradation activity in the visible range was tested using nonylphenol, which is one of the most harmful pollutants present in waste waters.
Economical and self-assembling polystyrene ‘Breath Figures’ method has been used to obtain a large polymeric 3D honey-comb structure substrate successively coated with metallic ductile films with ...thickness of few hundreds of nanometers deposited via DC magnetron sputtering. Finally, the obtained metallic 3D honey-comb structures have been functionalized by ceramic coatings such as titanium dioxide (TiO2) and aluminum oxide (Al2O3) via radio frequency-plasma enhanced chemical vapor deposition (RF-PECVD) having the role of the active parts.
The films have been investigated by scanning electron microscopy (SEM) and optical microscopy to define their morphology, while energy dispersive X-ray spectroscopy (EDS) measurements were carried out to determine their elemental composition.
The electrical characterization of the metallic films has been performed by using a four-point probe method. The sheet resistance RS of the films has been derived and the results discussed taking into account its dependence on the effective superficial length due to Breath Figures morphological benefit.
•Polystyrene honey-comb production•Metal coating on them via magnetron sputtering•PS substrate chemical removal obtaining self sustaining metallic honey comb film•PECVD of ceramic oxide coatings on metallic films for improved aspect ratio•Electrical measurements to verify the improved effective area
Over the past decade the increase of elderly population has determined a rise in the incidence of bone fractures, and the improvement of the implant–bone interface remains an open problem. ...Metal-organic chemical vapour deposition (MOCVD) has recently been proposed as a technique to coat orthopaedic and dental prostheses with metal nanostructured oxide films either through the decomposition of oxygenated compounds (single-source precursors) or the reaction of oxygen-free metal compounds with oxygenating agents. The present study was performed to assess the in vivo biocompatibility of commercially pure Ti (control material: TI/MA) implants (∅ 2
mm×5
mm length) coated with nanostructured TiO
2 films by MOCVD (Ti/MOCVD) and then inserted into rabbit femoral cortical (middhiaphysis) and cancellous (distal epiphysis) bone. Histomorphometric, ultrastructural and microhardness investigations were carried out. Four and 12 weeks after surgery, significant (
p<0.0005) increases in AI of Ti/MOCVD implants were observed as compared to Ti/MA implants (distal femoral epiphysis: 4 weeks=8.2%,
ns; 12 weeks=52.3%,
p<0.005; femoral diaphysis: 4 weeks=20.2%,
p<0.0005; 12 weeks=10.7%,
p<0.005). Bone microhardness results showed significant increases for the Ti/MOCVD versus Ti/MA implants at 200
μm in the femoral diaphysis (4 weeks=14.2,
p<0.005) and distal femoral epiphysis (12 weeks=14.5,
p<0.01) at 4 and 12 weeks, respectively. In conclusion, the current findings demonstrate that the nanostructured TiO
2 coating positively affects the osseointegration rate of commercially pure Ti implants and the bone mineralization at the bone–biomaterial interface in both cortical and cancellous bone.
Nine areas of the brain were studied by electron paramagnetic resonance spectroscopy and total reflection X-ray fluorescence spectroscopy to measure paramagnetic metal ions, free radicals ...(neuromelanin), and total metal content. We also determined the extent of accumulation of metal ions by melanins incubated in homogenates of a region of the brain (putamen). The electron paramagnetic resonance spectra of metal ions varied considerably among areas of the brain. There was no correlation between total content of particular metal ions (iron was especially pertinent) and the observed electron paramagnetic resonance spectra, except that the substantia nigra appeared more consistently to have a prominent g = 4 electron paramagnetic resonance signal characteristic of ferric iron in a rhombic state. Only the substantia nigra, and to a lesser extent the locus coeruleus, had a free radical signal consistent with that of neuromelanin. This signal was much more prominent in the unprocessed substantia nigra but when metal ions were removed (reducing the amount of suppression of the electron paramagnetic resonance signal of neuromelanin due to dipole-dipole broadening from nearby metal ions), the electron paramagnetic resonance spectrum of neuromelanin of the locus coeruleus increased much more than that of the substantia nigra. This suggests that the structure of the pigment may differ in these two regions.
Incubating synthetic melanins with homogenates of putamen resulted in accumulation of metal ions on the melanins with the concentrations of the three metal ions, relative to their values in the putamen, increasing by factors of 20–30 3–4 and 25–30 for iron, copper, and zinc, respectively. This suggests that the metal content of isolated neuromelanin may include metal ions which became bound to the neuromelanin during the isolation procedure.
Background The Leishmania (Viannia) braziliensis complex is responsible for most cases of New World tegumentary leishmaniasis. This complex includes two closely related species but with different ...geographic distribution and disease phenotypes, L. (V.) peruviana and L. (V.) braziliensis. However, the genetic basis of these differences is not well understood and the status of L. (V.) peruviana as distinct species has been questioned by some. Here we sequenced the genomes of two L. (V.) peruviana isolates (LEM1537 and PAB-4377) using Illumina high throughput sequencing and performed comparative analyses against the L. (V.) braziliensis M2904 reference genome. Comparisons were focused on the detection of Single Nucleotide Polymorphisms (SNPs), insertions and deletions (INDELs), aneuploidy and gene copy number variations. Results We found 94,070 variants shared by both L. (V.) peruviana isolates (144,079 in PAB-4377 and 136,946 in LEM1537) against the L. (V.) braziliensis M2904 reference genome while only 26,853 variants separated both L. (V.) peruviana genomes. Analysis in coding sequences detected 26,750 SNPs and 1,513 indels shared by both L. (V.) peruviana isolates against L. (V.) braziliensis M2904 and revealed two L. (V.) braziliensis pseudogenes that are likely to have coding potential in L. (V.) peruviana. Chromosomal read density and allele frequency profiling showed a heterogeneous pattern of aneuploidy with an overall disomic tendency in both L. (V.) peruviana isolates, in contrast with a trisomic pattern in the L. (V.) braziliensis M2904 reference. Read depth analysis allowed us to detect more than 368 gene expansions and 14 expanded gene arrays in L. (V.) peruviana, and the likely absence of expanded amastin gene arrays. Conclusions The greater numbers of interspecific SNP/indel differences between L. (V.) peruviana and L. (V.) braziliensis and the presence of different gene and chromosome copy number variations support the classification of both organisms as closely related but distinct species. The extensive nucleotide polymorphisms and differences in gene and chromosome copy numbers in L. (V.) peruviana suggests the possibility that these may contribute to some of the unique features of its biology, including a lower pathology and lack of mucosal development.
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