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Non-destructive thermal and optical characterization of materials can be successfully performed by the photo-acoustic technique. In this work, this technique has been applied to the measure of thermal conductivity in porous silicon by considering the photo-acoustic response at fixed frequency of samples having the same porosity but different thicknesses. Experimental data are interpreted in terms of a model which takes into account both scattering effects and the contribution to the photo-acoustic signal of the interstitial gas expansion. The measured thermal conductivity is found to be lower than the one reported for crystalline silicon by two orders of magnitude. A discussion of the photo-acoustic signal dependence on the morphology of the porous medium is also presented. [Copyright &y& Elsevier]

Abstract: Tin oxide nanostructures are currently considered as promising materials for gas sensing. Some of their physical properties, such as visible light photoluminescence, are still not fully understood and require further investigations. In this work we report on the quenching of tin oxide nanowires photoluminescence induced by nitrogen dioxide adsorption at the ppm and sub-ppm level. The recombination dynamics was investigated by means of time-resolved photoluminescence, finding non-exponential decay profiles. Neither the photoluminescence spectral shape nor the decay rates are found to depend significantly on the nitrogen dioxide concentration, suggesting that the gas-nanostructure interaction resides in a net reduction of the density of states which are responsible for the radiative transitions. [Copyright &y& Elsevier]

Hydrogenated microcrystalline silicon (μc-Si:H) films were prepared by Plasma Enhanced Chemical Vapor Deposition from a mixture of silane highly diluted in hydrogen. The effect of the silane concentration on the deposition rate and on the optical, electrical and structural properties were investigated. The silane concentration appears to control orientation and grain size. Highly conductive μc-Si:H films were grown with high deposition rate at silane concentration of 3%. These films show an enhancement of the optical absorption in the near infrared region. In the visible region the absorption is lower than a-Si:H, however the transient PC signal, induced by 532 nm laser pulses (6 ns time duration), shows an high amplitude and a width comparable with the optical pulse one. μc-Si:H materials can be used for fast photodetectors of pulsed visible light. [Copyright &y& Elsevier]

Abstract: The role of surface oxygen vacancies in the optical properties of tin dioxide nanobelts is investigated in this paper. Using a first-principles approach, based on the density functional theory combined to a very accurate exchange correlation functional, we characterize SnO2 (101), that is the nanobelt largest surface. We show that the presence of surface oxygen vacancies leads to the appearance of (i) occupied states located at about 1eV above the valence band and (ii) unoccupied states lying in resonance with the conduction band. Photoluminescence characterization performed on samples of SnO2 nanobelts at low temperature shows that the basic spectral features of luminescence are in excellent agreement with theoretical predictions. [Copyright &y& Elsevier]

PCLS from lung resections or explants have gained increasing attention as novel human disease models and to overcome limitations of acellular scaffold models. This method is appropriate for the assessment of new drug efficacy and the evaluation of cellular drug targets in a whole tissue model. We have recently developed and patented functionalized liposomes, named "xhalip", loaded with tyrosine kinase inhibitors for the inhalatory treatment of Chronic Lung Allograft Dysfunction (CLAD) and other form of immune-inflammatory lung fibrosis. To assess the anti-remodeling action of xhalip, we developed and applied an Endothelial Mesenchymal Transition (EMT) model of PCLS obtained from healthy non smokers-lung tissue (from graft volume reduction/lobectomy for malignancy). PCLS were treated either with a "fibrogenic cocktail" composed by platelet lysate (PL) and TGFbeta (10ng/ml), or purified NETs (from 2.5 × 106 neutrophils activated with PMA). Gene expression of α-SMA (ACTA2), type 1a1 collagen (COL1A1) and type3a1 collagen (COL3A1) was monitored up to 96 hours to reveal development of EMT. ACTA2 expression was significant up-regulated by NETs compared to control cells (2-fold at 48 hrs and 3-fold increase at 72 hrs, p<0.01), as well as PL+TGFbeta treatment (2.5-fold at 48 hrs and 2-fold increase at 72 hrs, p<0.01). We also observed significant upregulation at 48 h of COL1A1 and COL3A1, up to 96 hrs only with PL+ TGFbeta treatment. Treatment of stimulated PCLS with HA-coated and Imatinib-loaded xhalip, or with free drug imatinib, was associated to a significant reduction of ACTA2 (70-50% decrease at 48 hrs with xhalip and 50-30% for Im at 48 and 72 hrs respectively), COL1A1 (60%-10% with both treatment at 48 and 72 hrs) and COL3A1 (reduced by 40% and 5% with both treatment at 48 and 72 hrs, respectively). In conclusion, human-derived PCLS, can allow the assessment of new therapeutic strategies on an ex vivo EMT model. Imatinib-loaded xhalip are a promising strategy for the local treatment of CLAD, in particular of the obstructive phenotype. [ABSTRACT FROM AUTHOR]

Abstract: Tin–titanium solid solutions at increasing Ti molar fraction, x =0.1, 0.3, 0.5, 0.7 and 0.9, were prepared by symplectic gel co-precipitation (SGC) method from stoichiometric hydroalcoholic solutions of Ti and Sn metalalkoxides. Structural, spectroscopic and electrical analyses were performed and the results have been correlated. The peaks of the XRD patterns change from the positions of SnO2 cassiterite to those of TiO2 rutile, when increasing the Ti content in the solid solution. Photoluminescence (PL), FT-IR and UV–vis-NIR characterizations are in agreement with the formation of solid solutions: PL peak falls either in the visible or IR region, depending on the Ti content in the solid solution; FT-IR spectra reveal a progressive upward shift of the high-frequency absorption edge of the skeletal vibration modes from the value of SnO2 to one of TiO2 on increasing the Ti content; UV–vis-NIR spectra reveal a progressive downward shift of the VB–CB absorption edge on increasing Ti content. The changes induced by CO interaction at increasing temperature in the FT-IR and UV–vis-NIR spectra revealed a different behaviour of the materials following the Ti content: for the lowest Ti molar fraction (x =0.1) as well as for SnO2 the reduction gives rise to mono-ionized oxygen vacancies, for the other solid solution the loss of reticular oxygen gives rise to doubly ionized oxygen vacancies and to Ti3+ ions. From the electrical-conductance point of view, two groups of films can be identified: pure SnO2 and the solid solution with x =0.1, and all the other solutions including pure titania, in agreement with the results of FT-IR investigations. The best response to carbon monoxide was achieved by the solutions with x =0.3 and x =0.5. Opposite to electrical properties, exhibiting good responses to reducing gases, these agents did not appreciably modify the PL yield of the solid solutions. Conversely, PL emissions were sensitive to NO2, particularly for Ti0.5Sn0.5O2. [Copyright &y& Elsevier]

Previous studies aimed to evaluate cytokine profile of Broncho-alveolar Lavage Fluids in Lung Transplant recipients (LTxR) during stability or during complications such as infections or rejection showed that no specific profile correlates with acute rejection while during Infectious episode. Aim of our study was to assess the signature of pro-inflammatory and interferons in LTxR in stable clinical conditions in absence of Infections and rejection. Ten BALf of stable LTxR were analyzed by a multiplex bead-based immunoassay to evaluate twelve cytokines (IL-1β; IL-6; CXCL10; TNFα; IFN-λ1; IL-8; IL-12; IFN-α2; IFN-λ2,3; IFN-β; IL-10; IFN-ϒ). The results obtained were compared to a sample of IPF patients (n°10), Obstructive CLAD LTR (BOS n°6) and healthy controls (HC, n°3). All samples were included after exclusion of concomitant sign/symptoms of infection. In a subsample of LTR (n°10) and IPF (n°10) IL1-β mRNA expression levels were analyzed on BAL cells. Among all tested cytokines only IL-1β and IL-8 resulted significantly dysregulated among study groups. In fact, we observed that stable LTxR showed higher IL-1β (1.04; 0, 3.915) and IL-8 (43.74; 24.29, 205.5) in BALf compared to HC and IPF affected patients (p &lt 0.05). The result of IL-1β was confirmed also by the analysis of mRNA in cells of respective BAL. Comparing IL-1β and IL-8 in BALf of stable LTxR and BOS-affected patients, IL-1β was significantly higher in BOS patients (6.81; 2.5, 24.71), while no significant variation was found for IL-8. While previous report showed a significant association between Infections and IL-1β and IL-8 levels in LTxR, we demonstrate that there is a significant upregulation of these cytokines also in stable condition with respect to HC and also with respect to a pro-fibrotic lung disease (IPF). In addition, IL-1β increases significantly in patients developing BOS, thus suggesting a possible pathogenic role and therapeutic target [ABSTRACT FROM AUTHOR]

Bronchiolitis obliterans Syndrome (BOS) is a major long term complication after lung transplant. The role of Neutrophil (Neu) activation in BOS pathogenesis has been repeatedly suggested but needs to be fully clarified. Human Neutrophil Elastase (HNE) as well as complexes of alpha-1-antitrypsin (AAT)/HNE are more frequently detected in BAL-f from BOS patients thus suggesting chronic Neu activation BOS. NETosis is a mechanism of Neu response to pathogens which can drive severe epithelial injury. Here, we aim to analyze possible role of NETosis in BOS by assessing number of Neu and related markers in BAL-f. A total of 16 BAL samples from BOS (n° 8, 3 BOS1, 2 BOS2 and 2 BOS3) and from stable lung recipients (n°8) were included. Patients with sarcoidosis (Sarco) were used as control (n°3). The following measures were performed: BAL Neu counts; HNE, IL1beta and IL8 (ELISA); NETs (measuring HNE-DNA complexes by ELISA); AAT/HNE complexes (WB). NETs were measurable in all BAL samples from Tx recipients, with a not-significant trend towards higher values among BOS patients (p=0.275). Interestingly NETs levels did not correlate with Neu counts (r=0.575; p=0.143) but, limited to BOS patients, significantly correlated with IL-8 (r=0.786; p=0.028), HNE (r=0.736; p=0.028), and AAT/HNE complexes (r=0.73; p=0.05).No correlation with IL1beta levels was found. This is the first preliminary evidence of the possibility to detect NETs in BAL-f of lung transplant recipients and, interestingly points out that NETs levels do not seem to correlate simply with Neu counts but rather with inflammation and specific Neu activation. Thus, they could potentially represent a marker of higher inflammatory state. In addition, given the evidence that NETs drive epithelial cell injury and cause EMT their significant pathogenic role in BOS can be suggested and future therapeutic strategies can be hypothesized. [ABSTRACT FROM AUTHOR]