Silvia Ponce

Obstructive sleep apnoea in the elderly: role of continuous positive airway pressure treatment

CPAP is effective in elderly patients with severe OSA in clinical and neurocognitive terms improving quality of life http://ow.ly/KHfh9 Almost all the information about the effect of continuous positive airway pressure (CPAP) in patients with obstructive sleep apnoea (OSA) comes from clinical trials involving only middle-aged patients. The objective of this study was to assess the effect of CPAP treatment in elderly patients with severe OSA on clinical, quality-of-life and neurocognitive spheres. We performed an open-label, randomised, multicentre clinical trial in a consecutive clinical cohort of 224 elderly (≥70 years old) patients with confirmed severe OSA (apnoea–hypopnea index ≥30) randomised to receive CPAP (n=115) or no CPAP (n=109) for 3 months. A sleep study was performed by either full polysomnography or respiratory polygraphy. CPAP titration was performed by an autoCPAP device. The primary endpoint was quality of life (Quebec Sleep Questionnaire) and secondary endpoints included sleep-related symptoms, presence of anxiety/depression, office-based blood pressure and some neurocognitive tests. The mean±sd age was 75.5±3.9 years. The CPAP group achieved a greater improvement in all quality-of-life domains (p<0.001; effect size: 0.41–0.98), sleep-related symptoms (p<0.001; effect size 0.31–0.91) as well as anxiety (p=0.016; effect size 0.51) and depression (p<0.001; effect size: 0.28) indexes and some neurocognitive tests (digit symbol test (p=0.047; effect size: 0.20) and Trail Making Test A (p=0.029; effect size: 0.44)) in an intention-to-treat analysis. In conclusion, CPAP treatment resulted in an improvement in quality of life, sleep-related symptoms, anxiety and depression indexes and some neurocognitive aspects in elderly people with severe OSA.

Effect of γ-irradiation on the growth of ZnO nanorod films for photocatalytic disinfection of contaminated water.

The growth of ZnO nanorods on a flat substrate containing γ-irradiated seeds and their ability to photocatalytically eliminate bacteria in water were studied. The seed layer was obtained, by the spray pyrolysis technique, from zinc acetate solutions γ-irradiated within the range from 0 to 100 kGy. Subsequently, to grow the rods, the seeds were immersed in a basic solution of zinc nitrate maintained at 90 °C. The rate of crystal growth on the seed layer during the thermal bath treatment was kept constant. The resulting materials were characterized morphologically by scanning electron and atomic force microscopies; X-ray diffraction was used to study their morphology and structure and ultraviolet-visible spectroscopy to determine their absorbance. The obtained seed films were morphologically dependent on the radiation dose and this was correlated with the ZnO nanorod films which presented a texture in the (002) direction perpendicular to the substrate. The rods have a hexagonal mean cross section between 20 and 140 nm. Using these rods, the photocatalytic degradation of Escherichia coli bacteria in water was studied; a positive influence of the crystalline texture on the degradation rate was observed.

Solar Water Disinfection Studies With Supported TiO2 and Polymer-Supported Ru(II) Sensitizer in a Compound Parabolic Collector

Solar water disinfection was performed using TiO 2 and a Ru(II) complex as fixed catalysts located in a compound parabolic collector photoreactor. Studies were performed in the laboratory as well as at a greenfield site. Under laboratory conditions, natural water contaminated with cultured bacteria was photocatalytically treated and the influence of the photolysis as well as of both catalysts was studied. Experiments were performed with contaminated water flowing at 12 l/min; under these conditions, photocatalytic experiments performed with a supported heterogeneous photocatalyst (Ahlstrom paper impregnated with TiO 2 ) showed it to be effective in degrading bacteria in water. The Ru complex catalyst, however, showed no clear evidence for disinfecting water, and its efficiency was comparable to the simple photolysis. Under on-site experiments, bacteria contaminated water from the Yaurisque river at Cusco, Peru was treated. As a general trend, after photocatalytic treatment a reduction in the E-coli population present in water was observed. Whenever disinfection was achieved in the experiments, no regrowth of bacteria was observed after 24 h. However, a reduction in the prototype efficiency was observed both in laboratory and on-site experiments. This was ascribed to aging of the photocatalyst as well as due to the deposition of particles onto its surface. In cases in which incomplete disinfection resulted, a low rate of E-coli growth was observed 24 h after ending the experiment. However, pseudomones seem to be resistant to the treatment.

Synthesis and Characterization of ZnO Nanorod Films on PET for Photocatalytic Disinfection of Water

Abstract ZnO nanorods (ZnO NRs) were grown on ZnO seeded polyethylene tert-phtalate (PET) substrates obtained from recycled soda bottles at low temperatures (90 °C) from Zn2+ precursors in alkaline aqueous solution. The ZnO seeds were deposited on the PET substrates by spray gel (SG) or dip coating (DC) from a ZnO methanol sol. In the case of SG, the PET substrate was heated at 90 °C during the spray process. By the other hand the ZnO seed layers obtained by dip coating were heated at 90 °C or 130 °C for 10 minutes among coatings. Before seeding two procedures were made on PET surface for improving seed adhesion: 1) PET surface was mechanically roughened with sand paper 1200. 2) PET surface was chemically treated with a solution of NaOH in ethanol. The relationship between the microstructure of the ZnO NRs films as function of the PET surface treatment and the photocatalytic antibacterial activity for E. Coli disinfection, was determined through a detailed characterization of the material. The highest photocatalytic antibacterial activity was performed by ZnO NRs films grown on seeds deposited by dip coating with 10 layers, 5 minutes of chemical treatment of PET surface and a thermal treatment at 130° C among coatings. With these films the population of viable E. Coli dropped more than seven orders, from 3×108 to 101 CFU.

Titanium Dioxide onto Polyethylene for Water Decontamination

Abstract TiO2 aqueous suspensions under illumination of UV range (310-400 nm UV-A) have demonstrated a big potential for water decontamination and disinfection for human consume. Separation of TiO2 from the process is not easy. Supporting TiO2 to a proper substrate avoid the separation step after the photocatalytic treatment. This procedure results very interesting for the manufacturing of economic decontamination devices, which could be made with lightweight and flexible materials, bringing much versatility for the design of reactors for water decontamination. Based on those requirements, supporting TiO2 over polyethylene results ideal for that purposes due to its physicochemical properties, good transparency and low cost. In this work we evaluated different methods to support titanium dioxide nanoparticles onto polyethylene. The catalyst was characterized by X-ray diffraction and transmission electron microscopy (TEM) for structural analysis. TEMwas also used for morphology characterization. UV-Visible and infrared spectroscopy were used to study the inter band and molecular absorptions respectively. Material ability to perform photocatalytic degradation of rhodamine and bacteria (E-coli) in water, were studied. Obtained results suggest a very promissory applicability of the catalyst for water purification application in rural areas.