Adult respiratory distress syndrome profiles by computed tomography

Ten patients with full-blown ARDS, on mechanical ventilation with PEEP underwent lung CT. Seven normal subjects were also studied. Three tomographic levels (apex, hilum, and base) were selected. The most consistent morphologic finding in ARDS was the presence of densities in the dependent regions of the lung. Assuming that the three levels were a representative sample of the whole lung, the lung weight was computed from the mean CT number and lung gas volume. Analysis of the CT number frequency distribution revealed three definite patterns of distribution: type 1, bimodal, with one mode in the normal CT number range; type 2, unimodal narrow distribution, with the mode in the CT range of water; and type 3, unimodal broad distribution in the abnormal CT number range.

Emerging pollutant mixture mineralization by TiO2 photocatalysts. The role of the water medium

Pharmaceutics and personal care products (PPCPs) are raising growing concern due to their widespread usage and resistance to conventional remediation techniques. Several of them raise significant health and environmental concerns, especially when present in complex mixtures. Due to their chemical resistance, Advanced Oxidation Processes (AOPs) are needed for their complete removal from surface and wastewaters. In the present work, photocatalysis by titanium dioxide (TiO₂) under UV and simulated solar irradiation was adopted to degrade tetracycline hydrochloride, paracetamol, caffeine and atenolol, both as single pollutants and in mixtures. All molecules showed high removal and mineralization degrees. Moreover, no interference effects decreased the efficiency of the processes in the case of pollutant mixtures, achieving 60% of mineralization after 6 h. An immobilized TiO₂ system was also developed by depositing titania on titanium meshes. A 50% mineralization degree of the pollutant mixture was obtained after 6 h, revealing a suitable efficiency for field applications. Eventually, the impact of the matrix composition on the photocatalytic efficiency was investigated by studying the reaction both in simulated drinking water and in commercial bottled mineral water. The scavenger role played by HCO₃^- species appears to be dominant in inhibiting the mineralization.

Apoptosis in human lung epithelial cells: triggering by paraquat and modulation by antioxidants

Recent results have shown that apoptosis is an important feature of the normal and injured lung epithelium, but little conclusive evidence is available about the exact intracellular mechanisms involved. In this work, we studied apoptotic cell death in the established human lung epithelial cell line, A549, by evaluating the ability of the pulmonary toxin, paraquat (1,1'-dimethyl-4, 4'-bipyridylium dichloride), to act as a trigger, and assessing the ability of ascorbic acid and N-acetyl-cysteine (NAC) to modulate the process. The analysis of nuclear and cellular morphology along with TUNEL staining showed that paraquat is an inducer of apoptosis. A549 cells incubated with sublethal doses of paraquat for up to 24 h showed no apoptotic features but, their following incubation in paraquat-free medium resulted in a time-dependent appearance of apoptosis. The antioxidants, ascorbic acid and NAC, proved effective in reducing paraquat-induced apoptosis, and therefore were seen as protective agents. Finally, we propose an experimental model for investigating some of the key steps in the apoptotic programme in alveolar cells.

Influence of MPP+ on the state of tubulin polymerisation in NGF-differentiated PC12 cells

Cytoskeletal proteins have been reported as constituents of cytoplasmic inclusions typical of degenerated neurones in Parkinson's disease and, in addition, the involvement of cytoskeleton in the mechanism of action of the parkinsonism-producing neurotoxin MPP+ is emerging. Here we investigate the influence of MPP+ on the dynamic behaviour of microtubules. Neurone-like cells derived from a rat pheochromocytoma cell line (PC12) and differentiated with nerve growth factor are used as a model system. We found that sublethal doses of the neurotoxin markedly affect the state of tubulin polymerisation: polymerised tubulins significantly decreased, whereas an increase of unpolymerised alpha-tubulin was observed. Since the concentration of unassembled tubulin directly regulates tubulin synthesis by a feedback mechanism, we studied alpha- and beta-tubulin synthesis by metabolic labelling of PC12 cells with [35S] methionine and following immunoprecipitations. The results showed the significant decrease of labelling in both the microtubule subunits in cells exposed to the neurotoxin. We suggest that the MPP+-induced imbalance of tubulin polymerisation and synthesis represents a novel early step in the mechanism of action of the neurotoxin.

Self-cleaning properties in engineered sensors for dopamine electroanalytical detection

A self-cleaning reusable composite electrode is ad hoc designed to bypass the fouling problem connected with biomedical molecule detection (e.g. dopamine).

Regular ventricular rhythms before conversion of recent onset atrial fibrillation to sinus rhythm

The incidence of fast atrial tachycardias with regular ventricular rhythm was assessed in a population of 243 patients with recent onset (< 72 hours) atrial fibrillation (AF), without heart failure, randomly treated with single loading oral dose of propafenone (600 mg), flecainide (300 mg), digoxin (1 mg), or placebo for acute conversion to sinus rhythm (SR). Fast atrial arrhythmias developed in 14 (6%) patients: 6/92 treated with propafenone, 3/34 treated with flecainide, 1/25 treated with digoxin, and 4/92 who received placebo (P = NS). Heart rate > 175 beats/min with 1:1 AV conduction ensued in 4 cases: 2 treated with flecainide and 2 treated with placebo; in the other cases 2:1 AV conduction was observed. Widening of QRS during regular tachycardia was observed in 4 patients; 3 who received propafenone and 1 who received flecainide. Conversion to SR within 4 hours was achieved in 55/92 (60%) patients treated with propafenone, 20/34 (59%) patients treated with flecainide, 7/25 (28%) patients treated with digoxin, and 19/92 (20%) treated with placebo (P < 0.001 propafenone vs placebo and flecainide vs placebo; P < 0.05 propafenone vs digoxin and flecainide vs digoxin). Periods of regular tachycardia are expected in recent onset AF and may not necessarily represent a proarrhythmic effect of Class 1C drugs, rather than mark the transition from AF to SR. Class 1C agents are probably responsible for widening of the QRS complex seen during these tachycardias. Propafenone and flecainide appear equally effective in converting recent onset AF.

Wettability of bare and fluorinated silanes: a combined approach based on surface free energy evaluations and dipole moment calculations

The assessment of the surface free energy (SFE) of a material permits to control and predict a large number of physicochemical properties of a solid surface and its reactivity. Here, the surface energies of a series of bare and fluorinated silanes are determined by means of different semi-empirical models on the grounds of contact angle determinations for different solvents. Literature data are also considered in order to produce a series of films with increasing SFE. Wetting envelopes (WE) are obtained for the various surfaces in order to predict the wettability of the films by numerous commonly employed solvents. The polar and disperse components of the surface energies are obtained by the Owens-Wendt-Rabel-Kaelbe (OWRK) method; the values of the polar components are compared with gas-phase dipole moments obtained by theoretical calculations employing semi-empirical Hamiltonians. The sequences of the polar components of the SFE and of the calculated dipole moments for the different molecules are strictly the same. The interplay between theoretical and experimental approaches proves efficient in predicting the behavior of different systems and it could be employed in tuning the SFE of a solid surface with respect to its final applications.

Structural and Spectroscopic Investigations of Blue, Vanadium-Doped ZrSiO4 Pigments Prepared by a Sol−Gel Route

A sol-gel reaction starting from silicon and zirconium alkoxides, in water-ethanol mixtures, was employed to obtain vanadium-doped zirconium silicate powders (zircon). The reactions were performed by modulating both (a) the amount of the vanadium salt in the starting mixture and also (b) the amount of mineralizer (NaF). The products of the sol-gel reaction were calcined at 600, 800, 1000, and 1200 degrees C. The samples were characterized by X-ray powder diffraction (XRPD), electron paramagnetic resonance spectroscopy (EPR), scanning electron microscopy (SEM), X-ray absorption near-edge spectroscopy (XANES), and diffuse UV-vis-near-IR reflectance spectroscopy. Results from the structural, morphological, and optical characterization are examined and cross-compared to produce a consistent picture of the key factors leading to the formation, growth, and optical properties of the reaction products.

Photodegradation of Pollutants in Air: Enhanced Properties of Nano-TiO(2) Prepared by Ultrasound

Nanocrystalline TiO(2) samples were prepared by promoting the growth of a sol-gel precursor, in the presence of water, under continuous (CW), or pulsed (PW) ultrasound. All the samples turned out to be made of both anatase and brookite polymorphs. Pulsed US treatments determine an increase in the sample surface area and a decrease of the crystallite size, that is also accompanied by a more ordered crystalline structure and the samples appear to be more regular and can be considered to contain a relatively low concentration of lattice defects. These features result in a lower recombination rate between electrons and holes and, therefore, in a good photocatalytic performance toward the degradation of NO(x) in air. The continuous mode induces, instead, the formation of surface defects (two components are present in XPS Ti 2p(3/2) region) and consequently yields the best photocatalyst. The analysis of all the characterization data seems to suggest that the relevant parameter imposing the final features of the oxides is the ultrasound total energy per volume (E(tot)/V) and not the acoustic intensity or the pulsed/continuous mode.

Photocatalytic degradation of toluene in the gas phase: relationship between surface species and catalyst features

Photocatalytic activity of both commercial and homemade samples was tested for the degradation of toluene in the gas phase by using two different irradiation sources, UV and solar. The role played by humidity in affecting the final toluene degradation was discussed. Catalyst deactivation (due to the high toluene level, 1000 ppm) and subsequent regeneration, by washing with water, were analyzed. Highest degradations and corresponding kinetic constants were achieved in the case of the anatase/brookite composite samples, while the commercial ones (including P25 Degussa) showed lower efficiency. Various adsorbed aromatic species (benzoic acid, the major surface product hydroquinone, benzylic alcohol, benzaldehyde, and cresols) obtained by washing the exhaust catalysts were analyzed by HPLC. Parallel results were achieved by Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy. The presence of different photodegradation surface species for the various photocatalysts suggests the occurrence of different reaction pathways, depending on the fine physicochemical features of the specific TiO2 adopted in the reaction.

Hazardous o-toluidine mineralization by photocatalytic bismuth doped ZnO slurries

Photocatalytic mineralization of o-toluidine in aqueous media under UV/solar irradiation was achieved by bare and bismuth doped zinc oxide nanoparticles.

Breakthroughs in the Design of Novel Carbon-Based Metal Oxides Nanocomposites for VOCs Gas Sensing

Nowadays, the detection of volatile organic compounds (VOCs) at trace levels (down to ppb) is feasible by exploiting ultra-sensitive and highly selective chemoresistors, especially in the field of medical diagnosis. By coupling metal oxide semiconductors (MOS e.g., SnO₂, ZnO, WO₃, CuO, TiO₂ and Fe₂O₃) with innovative carbon-based materials (graphene, graphene oxide, reduced graphene oxide, single-wall and multi-wall carbon nanotubes), outstanding performances in terms of sensitivity, selectivity, limits of detection, response and recovery times towards specific gaseous targets (such as ethanol, acetone, formaldehyde and aromatic compounds) can be easily achieved. Notably, carbonaceous species, highly interconnected to MOS nanoparticles, enhance the sensor responses by (i) increasing the surface area and the pore content, (ii) favoring the electron migration, the transfer efficiency (spillover effect) and gas diffusion rate, (iii) promoting the active sites concomitantly limiting the nanopowders agglomeration; and (iv) forming nano-heterojunctions. Herein, the aim of the present review is to highlight the above-mentioned hybrid features in order to engineer novel flexible, miniaturized and low working temperature sensors, able to detect specific VOC biomarkers of a human's disease.

Microtubule assembly is directly affected by MPP(+)in vitro

The microtubular system is emerging as a cell target in neurodegeneration evoked by the Parkinsonism-inducing neurotoxin N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its toxic metabolite N-methyl-4-phenylpyridinium (MPP(+)). Looking for a direct effect of the neurotoxin on microtubules, we have undertaken an in vitro study by using microtubule protein purified from bovine brain. We show that MPP(+), but not MPTP, modifies the initial rate and the critical concentration of assembly without affecting microtubule ultrastructure. These findings strengthen the hypothesis for the role of microtubules in the transduction of MPP(+)neurotoxic effect and, probably, in neuronal cell death.

Aged Titania Nanoparticles: The Simultaneous Control of Local and Long-Range Properties

TiO(2) nanoparticles are obtained by combining a sol-gel preparative route with hydrothermal aging steps, performed in mild conditions, of varying time lengths. Both aged and un-aged samples are thermally treated at 300 and 600 degrees C, for the same length of time. The crystal structures, the phase composition, and crystallite sizes are analyzed by powder X-ray diffraction. Raman spectra of anatase nanocrystals with average sizes of 7-10 nm are reported and the correlation between the Raman band shape of the main feature at 144 cm(-1) and the crystallite size is discussed. Nitrogen physisorption by Brunauer-Emmett-Teller (BET) method is adopted to evaluate the particles surface area and mesopore size and size distribution. The role played by the hydrothermal step in affecting the physicochemical properties of the powders is discussed also with respect to the H(2)O/TiO(2) interactions as apparent from Raman spectroscopy investigations of the O-H stretching range (3000-3800 cm(-1)).