•Original study on the photo induced properties of Ni/nano-TiO2 electro-coatings.•Optimum self-cleaning character achieved via control of electrolysis conditions.•Hydrophilicity and photocatalytic ...activity improved by increasing TiO2 codeposition.•Structural characteristics of the Ni matrix strongly affect photo-induced properties.
Titanium dioxide (TiO2) nano-particles were immobilized in nickel matrix coatings using the direct current electrodeposition technique. The influence of nickel surface morphology and crystallographic orientation on the photocatalytic activity and photo-induced hydrophilicity of the composite coatings were investigated under UVA illumination. The overall self-cleaning character of the composites was improved following the titania codeposition, as both hydrophilic and photocatalytic effects are present. Simultaneous optimization of the two functionalities was possible via tuning the titania percentage, indicating that the corresponding properties of the composite coatings are associated also to the induced crystalline nickel orientation and the nickel grain size. In particular, the data indicate that both enhanced photocatalytic activity and photo-induced hydrophilicity are achieved by increasing amounts of titania nano-particles embedded in the Ni matrix in combination with reduced grain size of nickel crystallites that are oriented towards the 110 axis.
Mixed phase nanocrystalline TiO2 powders (anatase–rutile) (Degussa P25) were prepared by hydrothermal modification. The preparation procedure took place at 200 °C for 1–10 days in an autoclave system ...with water as the solvent. Thus, different degrees of modification were achieved. TiO2 water modified nanocrystalline thin films were immobilized on glass substrates by applying a doctor-blade's deposition technique. A variety of spectroscopic UV–vis reflectance, infra-red (IR), Raman, structural X-ray diffraction (XRD), N2 absorption (BET) and microscopic atomic force microscopy (AFM), scanning electron microscopy (SEM) techniques were applied to characterize the modified films. A model textile industry pollutant (methyl orange) was used in order to evaluate the photocatalytic efficiency of the modified material. Our results show that the photocatalytic activity of the modified films is improved by a factor of 2 when we extend the hydrothermal treatment up from 1 to about 4 days in the autoclave system. Scratch tests revealed favorable interconnection of the titania nanoparticles as well as significantly higher adhesion to the glass substrate for the modified films, in comparison to the original P25 material.
The sequential univalent reduction of oxygen generates superoxide, hydrogen peroxide, and hydroxyl radical. The generation of hydroxyl radical is dependent on catalysis by ferrous iron. In addition, ...superoxide and nitric oxide produce peroxynitrite, which spontaneously generates hydroxyl radical independently of iron-mediated catalysis. These agents have a variety of cellular actions, which render them suitable candidates as mediators of tissue destruction and cellular death. In the intact brain, superoxide and its derivatives cause vasodilation, mediated by opening of potassium channels, altered vascular reactivity, breakdown of the blood-brain barrier, and focal destructive endothelial lesions. These abnormalities are also seen in early reperfusion following brain ischemia. During reperfusion there is a marked transient increase in superoxide production. Vasodilation, abnormal vascular reactivity, and blood-brain barrier breakdown are inhibited by eliminating superoxide. Superoxide production during reperfusion may be initiated by glutamate via activation of alpha-amino-3-hydroxy-5-methylisoxasolepropionic acid (AMPA) receptors. These experimental findings have important implications for human cerebral ischemia. Agents directed at eliminating oxygen radicals must be administered before or in the early stages of reperfusion following ischemia. The therapeutic window appears to be narrow and limited to, at most, a few hours. The inhibition of AMPA receptors may be a promising approach to inhibit the production of oxygen radicals during ischemia-reperfusion of the brain.
Nanocrystalline titania thin films were prepared by deposition and annealing of titania sol–gel precursor materials, both non-hydrated solutions and hydrosols. The sol–gels were immobilized on glass ...substrates applying doctor blade and dip-coating deposition techniques. The nanoparticle size, determined by the full-width at half-maximum of the X-ray diffraction peaks as well as by shifting and broadening of the Raman modes, strongly depends on the precursor solution. Significant differences were also confirmed on the surface characteristics, roughness and complexity of the films by atomic force microscopy. The films present high activity towards photodecomposition of methyl orange azo-dye together with enhanced photo-induced superhydrophilicity under illumination with ultraviolet light. Judicious choice of the precursor material and efficient control of the deposition parameters may lead to the optimization of their photocatalytic and/or superhydrophilic properties.
Self-organized TiO(2) nanotubes with packed, vertically aligned morphology and different lateral characteristics were grown on Ti metal substrates by controlled electrochemical anodization in ...phosphate/HF and ethylene glycol/HF electrolytes. The wetting, photo-induced superhydrophilicity, and photocatalytic activity of the nanotubular materials were investigated under ultraviolet irradiation. The photoactivity of the TiO(2) nanotube arrays was analysed in terms of their morphological characteristics that were determined by means of scanning electron microscopy and atomic force microscopy in conjunction with geometrical modelling. The wetting and the UV-induced superhydrophilicity could be accordingly modelled by the Cassie-Baxter mode arising from the large scale roughness of the nanotubular arrays in combination with the Wenzel mode due to the small scale roughness induced by ridges at the outer tube surface. The photocatalytic activity of the TiO(2) nanotube arrays was further found to correlate quantitatively with the variation of the geometric roughness factor, verifying the strong impact of morphology on the photo-induced properties of the vertically oriented TiO(2) tubular architecture.
The photo-induced bioactivity of titanium dioxide was investigated in terms of determining the conditions for photocatalytic treatment of cancer cells and also exploring the molecular mechanisms ...involved in this process. Cultured MCF-7 and MDA-MB-468 breast cancer epithelial cells were irradiated, using UV-A light (wavelength 350
nm) for 20
min, in the presence of nanostructured titania aqueous dispersions prepared using the sol–gel technique. Detailed characterization of the titania sols confirmed the presence of the photocatalyst in the form of anatase nanoparticles. Two different techniques were employed to examine the effects on cell cycle and the viability of the treated culture: propidium iodide (PI) flow cytometric (FACScan) assays permitted the identification of treatment effects on the cell cycle and cell viability analysis (MTT assays) allowed the definition of the precise percentage of cells that are still alive and functionable, after the treatment. A selective action of both TiO
2 nanoparticles and photocatalytically activated titania was observed on the highly malignant MDA-MB-468 cells. Upon irradiation, these cells were induced to undergo apoptotic cell death, compared to the MCF-7 cells which were still unimpaired. This was profoundly revealed via Western blot analysis. The molecular mechanism of apoptosis is associated at least in part with increase of caspase-3-mediated poly(ADP-ribose) polymerase (PARP) cleavage.
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•785 nm micro-Raman analysis of colorectal tissues from ten cancer patients.•Clustering in 5 Tissue Spectral Profiles: typical, fat, lipid/blood/collagen-rich.•Cancer tissues present ...uniform spectroscopic characteristics and normal diverse.•81% accuracy in normal/cancerous tissues classification by tree-based ML algorithm.•Biochemical changes evidenced in cancer by Raman are due to collagen and proteins.
Human colorectal tissues obtained by ten cancer patients have been examined by multiple micro-Raman spectroscopic measurements in the 500–3200 cm−1 range under 785 nm excitation. Distinct spectral profiles are recorded from different spots on the samples: a predominant ‘typical’ profile of colorectal tissue, as well as those from tissue topologies with high lipid, blood or collagen content. Principal component analysis identified several Raman bands of amino acids, proteins and lipids which allow the efficient discrimination of normal from cancer tissues, the first presenting plurality of Raman spectral profiles while the last showing off quite uniform spectroscopic characteristics. Tree-based machine learning experiment was further applied on all data as well as on filtered data keeping only those spectra which characterize the largely inseparable data clusters of ‘typical’ and ‘collagen-rich’ spectra. This purposive sampling evidences statistically the most significant spectroscopic features regarding the correct identification of cancer tissues and allows matching spectroscopic results with the biochemical changes induced in the malignant tissues.
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► N-TiO2 exhibited effective degradation of MC-LR under UV-A, solar and visible light. ► Complete photocatalytic mineralization of MC-LR was achieved under UV-A and solar light. ► The ...organic nitrogen is mainly released as ammonium and nitrate ions.
In an attempt to face serious environmental hazards, the degradation of microcystin-LR (MC-LR), one of the most common and more toxic water soluble cyanotoxin compounds released by cyanobacteria blooms, was investigated using nitrogen doped TiO2 (N-TiO2) photocatalyst, under UV-A, solar and visible light. Commercial Degussa P25 TiO2, Kronos and reference TiO2 nanopowders were used for comparison. It was found that under UV-A irradiation, all photocatalysts were effective in toxin elimination. The higher MC-LR degradation (99%) was observed with Degussa P25 TiO2 followed by N-TiO2 with 96% toxin destruction after 20min of illumination. Under solar light illumination, N-TiO2 nanocatalyst exhibits similar photocatalytic activity with that of commercially available materials such as Degussa P25 and Kronos TiO2 for the destruction of MC-LR. Upon irradiation with visible light Degussa P25 practically did not show any response, while the N-TiO2 displayed remarkable photocatalytic efficiency. In addition, it has been shown that photodegradation products did not present any significant protein phosphatase inhibition activity, proving that toxicity is proportional only to the remaining MC-LR in solution. Finally, total organic carbon (TOC) and inorganic ions (NO2−, NO3− and NH4+) determinations confirmed that complete photocatalytic mineralization of MC-LR was achieved under both UV-A and solar light.
The King–Devick (K–D) test is often used as part of a multimodal assessment to screen for sport-related concussion. However, the test involves reading numbers, and little is known about variation in ...baseline performance on the K–D by reading skill level. We conducted a cross-sectional study analyzing data from the Concussion Assessment, Research and Education (CARE) Consortium to assess differences in baseline performance on the K–D associated with factors that impact reading skill level (learning disorder LD and primary home language other than English PHLOTE), while controlling for covariates (gender, type of sport, attentional issues, history of concussion and modality of administration). We had a sample of 2311 student-athletes (47% female), and multivariate regression indicated an average K–D performance time of 40.4 s. Presence of LD was associated with a 3.3 s slower K–D time (95% CI 1.9–4.7,
p
< 0.001), and PHLOTE was associated with a 2.6 s slower K–D time (95% CI 1.2–4.0,
p
< 0.001), after controlling for other covariates. These results suggest caution in the use of normative data with the K–D. Future studies should explore the impact of factors associated with reading skill level on sensitivity of the K–D in detecting concussion.
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