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 sleeprelated 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 qualityof-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. @ERSpublications CPAP is effective in elderly patients with severe OSA in clinical and neurocognitive terms improving quality of life

Mesoporous silicon is a biocompatible, biodegradable material that is receiving increased attention for pharmaceutical applications due to its extensive specific surface. This feature enables to load a variety of drugs in mesoporous silicon devices by simple adsorption-based procedures. In this work, we have addressed the fabrication and characterization of two new mesoporous silicon devices prepared by electrochemistry and intended for protein delivery, namely: (i) mesoporous silicon microparticles and (ii) chitosan-coated mesoporous silicon microparticles. Both carriers were investigated for their capacity to load a therapeutic protein (insulin) and a model antigen (bovine serum albumin) by adsorption. Our results show that mesoporous silicon microparticles prepared by electrochemical methods present moderate affinity for insulin and high affinity for albumin. However, mesoporous silicon presents an extensive capacity to load both proteins, leading to systems were protein could represent the major mass fraction of the formulation. The possibility to form a chitosan coating on the microparticles surface was confirmed both qualitatively by atomic force microscopy and quantitatively by a colorimetric method.Mesoporous silicon microparticles with mean pore size of 35 nm released the loaded insulin quickly, but not instantaneously. This profile could be slowed to a certain extent by the chitosan coating modification. With their high protein loading, their capacity to provide a controlled release of insulin over a period of 60-90 min, and the potential mucoadhesive effect of the chitosan coating, these composite devices comprise several features that render them interesting candidates as transmucosal protein delivery systems.

This work aims at studying of electrochemical oxidation of porous silicon (PSi) and its behaviour in simulated body fluid (SBF). Continuing electrochemical oxidation of PSi introduces gradual changes in morphology of the porous structure and composition of PSi. As a result, interaction between this material and SBF is changed. As more oxidized is the PSi sample, slower is the dissolution process (biodegradability) and more easily it becomes covered by the calcium-phosphorous deposits from SBF (bioactivity). We observed that crystalline hydroxyapatite HA phase could be deposited in a very homogeneous manner onto OxPSi layers immersed in SBF at 36.5 o C during 30 days.

Mesoporous silicon has become a material of high interest for drug delivery due to its outstanding internal surface area and inherent biodegradability. We have previously reported the preparation of mesoporous silicon microparticles (MS-MPs) synthesized by an advantageous electrochemical method, and showed that due to their inner structure they can adsorb proteins in amounts exceeding the mass of the carrier itself. Protein release from these MS-MPs showed low burst effect and fast delivery kinetics with complete release in a few hours. In this work, we explored if tailoring the size of the inner pores of the particles would retard the protein release process. To address this hypothesis, three new MS-MPs prototypes were prepared by electrochemical synthesis, and the resulting carriers were characterized for morphology, particle size, and pore structure. All MS-MP prototypes had 90 µm mean particle size, but depending on the current density applied for synthesis, pore size changed between 5 and 13 nm. The model protein α-chymotrypsinogen was loaded into MS-MPs by adsorption and solvent evaporation. In the subsequent release experiments, no burst release of the protein was detected for any prototype. However, prototypes with larger pores (>10 nm) reached 100% release in 24–48 h, whereas prototypes with small mesopores (<6 nm) still retained most of their cargo after 96 h. MS-MPs with ∼6 nm pores were loaded with the osteogenic factor BMP7, and sustained release of this protein for up to two weeks was achieved. In conclusion, our results confirm that tailoring pore size can modify protein release from MS-MPs, and that prototypes with potential therapeutic utility for regional delivery of osteogenic factors can be prepared by convenient techniques.

A new type of oscillation emerging during copper immersion plating on silicon in solutions containing HF was observed. It is the spontaneous oscillation of open-circuit potential rather than the oscillations which have been observed on silicon under high polarization. The oscillation appears at less-noble potential and in a limited HF concentration range, and the amplitude is small. The behavior is affected by the type of dopant and dopant concentration and by the surface condition. The phenomenon is likely to be explained based on reactions occurring during immersion plating in the presence of fluoride ions: the oxide formationbreakdown-repair model. However, some results cannot be simply explained by the model.

PACS 05.45.Xt, 82.45.Qr, 82.45.Vp This work studies the influence of experimental conditions on the occurrence and development of oscillations of the open-circuit potential (OCP) of silicon immersed in aqueous solution of 0.01 M CuSO 4 + 0.06 M HF. The oscillations are very regular and last for days without any tendency to diminish. We show that they are quite sensitive to the temperature of the electrolyte, its viscosity, stirring, relative concentration of components, etc. We also present a phenomenological model to explain the oscillatory OCP behavior. Acknowledgement The work was done as part of the R&D project MAT 2001-3203 financed by the Interministerial Commission of Science and Technology of Spain. phys. stat. sol. (a) 202, No. 8 (2005) / www.pss-a.com 1591

In order to improve the bioactivity of porous silicon chemically functionalized by acetylene (PSi–C) and stimulate the calcium‐phosphorous (hydroxyapatite) deposition on this material from a simulated body fluid, electrochemical oxidation of the PSi–C templates has been employed. The initial functionalization by acetylene was done at 500 °C in a N2 + C2H2 gas stream of 1:1 ratio for 15 minutes; further electrochemical oxidation was performed in 80% phosphoric acid. The morphology and chemical composition of initial and oxidized porous structures were studied by the high resolution SEM technique and FTIR spectroscopy. Initial chemical functionalization leads to a very stable (practically bio‐inert) material that after electrochemical oxidation becomes bioactive. We observed that the hydroxyapatite phase has been homogeneously deposited on the electrochemically oxidized PSi–C material immersed in the SBF of Kokubo formulae at 36.5 °C just after two weeks. The layer of hydroxyapatite grown on the surface after 30 days of immersion was compact, crystalline and as thick as 5 μm. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Morphological and structural changes in porous silicon por-Si grown on differently doped Si wafers under anodic oxidation in phosphoric acid were studied. The two degrees of oxidation were confirmed: slighter (pore walls) and stronger (bulky) oxidation. Slighter oxidized por-Si does not experience any structural or morphological changes but chemical composition of the pore walls is gradually changed to Si-OH terminations. Stronger oxidation is accompanied by progressive morphological and structural transformations. Conductivity of the porous layer plays a significant role in the observed behavior. In less doped samples only a stronger oxidation started at the bottom of the porous layer is found. Porous layer becomes electrically separated from the Si wafer (electrode) and surface Si-Hx groups are preserved. Thus, doping level and conductivity of the Si wafer determines a spatial distribution of the porous electrode/ electrolyte interface and possibility to conserve native chemical composition of por-Si after electrochemical oxidation.