Nanoscale investigation of photoinduced hydrophilicity variations in anatase and rutile nanopowders.

The photoactive properties of TiO2 are employed to develop surfaces with self-cleaning capabilities. Clearly, the fine-tuning of such surfaces for different applications relies on a holistic understanding of the different aspects that induce the self-cleaning behavior. Among those, the mechanisms responsible for the photoinduced surface alteration in the TiO2 allotropes are still not completely understood. In this study, TiO2 polymorphs nanopowders are investigated by combining the high spatial resolution observables of recently developed atomic force microscopy (AFM) based force spectroscopy techniques with diffuse reflection infrared Fourier transform spectroscopy (DRIFTS). Phase maps under irradiated and nonirradiated conditions for anatase and rutile suggest the existence of two distinct behaviors that are further discerned by energy analysis of amplitude and phase vs distance curves. Independently, surface analysis of anatase and rutile by means of DRIFTS spectroscopy reveals a readily distinguishable coexistence of dissociated water and molecular water on the two phases, confirming the stronger photoactivity of anatase. The peculiarity of the surface interaction under UV exposure is further investigated by reconstructing the force profiles between the oscillating AFM tip and the TiO2 phases with the attempt of gaining a better understanding of the mechanisms that cause the different hydrophilic properties in the TiO2 allotropes.

Postoperative troponin T elevation as a predictor of early acute kidney injury after orthotopic liver transplantation: a preliminary retrospective study.

BACKGROUND: Slight alterations in cardiac enzymes are frequently observed perioperatively among liver transplant patients. The significance of these changes in the absence of ongoing acute cardiac pathology is unknown. We sought to evaluate the link between early postoperative anomalies of serum cardiac troponin T (cTnT) in the absence of an evident cardiac cause and kidney injury during the first week of hospital stay. METHODS: We retrospectively enrolled 30 patients in the study, recording several perioperative variables, particularly cTnT on intensive care unit ICU arrival as well as 6 and 12 hours later. We grouped patients with cTnT levels >0.03 ng/mL as the high-TnT group; the others were control subjects. We recorded the highest serum creatinine, aspartate aminotransferase, alanine aminotransferase, and bilirubin levels during the first week of the hospital stay. Glomerular filtration rate (GFR) was calculated according to the Cockroft-Gault formula. RESULTS: Ten patients composed the high-TnT group. Their perioperative variables showed higher Model for End-Stage Liver Disease (MELD) scores and significantly greater incidences of acute kidney injury, failure, and dialysis need than control patients. GFR dropped from 118 to 66 mL/min among this group versus 112 to 105 mL/min in control subjects (P = .021). Binary logistic regression analysis revealed a higher association between the high-TnT group and acute kidney injury (P = .036) than with the MELD score (P = .719). CONCLUSIONS: Serum cTnT levels could be influenced by both preoperative and intraoperative conditions that predispose to kidney injury.

Anodic titanium oxide as immobilized photocatalyst in UV or visible light devices.

Titanium anodizing can be a powerful technique to generate photoactive oxides, strongly adherent to the metallic substrate, and to modify their chemical composition by inducing doping effects. This work investigates the photocatalytic behavior of differently obtained anodic TiO(2) films under UV and visible light irradiation, so as to define the best treatment for wastewaters purifiers. Anodizing was performed in H(3)PO(4) and H(2)SO(4) mixtures or in fluoride containing electrolytes. Morphology, elemental composition and crystal structure of the anodic films were characterized by XDR, GDOES and SEM. When amorphous oxides were obtained, an annealing treatment was used to promote the formation of anatase crystals. Annealing was also performed in nitrogen atmosphere to induce nitrogen doping. The photocatalytic efficiency of anatase-enriched TiO(2) was investigated in rhodamine B photodegradation. Doping was induced not only by annealing but also directly by anodizing, and generated photoactivity in both the UV and Vis components of light.