Photochemical versus Thermal Synthesis of Cobalt Oxyhydroxide Nanocrystals

Photochemical methods facilitate the generation, isolation, and study of metastable nanomaterials having unusual size, composition, and morphology. These harder-to-isolate and highly reactive phases, inaccessible using conventional high-temperature pyrolysis, are likely to possess enhanced and unprecedented chemical, electromagnetic, and catalytic properties. We report a fast, low-temperature and scalable photochemical route to synthesize very small (~3 nm) monodisperse cobalt oxyhydroxide (Co(O)OH) nanocrystals. This method uses readily and commercially available pentaamminechlorocobalt(III) chloride, [Co(NH3) 5Cl]Cl2, under acidic or neutral pH and proceeds under either near-UV (350 nm) or Vis (575 nm) illumination. Control experiments showed that the reaction proceeds at competent rates only in the presence of light, does not involve a free radical mechanism, is insensitive to O 2, and proceeds in two steps: (1) Aquation of [Co(NH3) 5Cl] 2+ to yield [Co(NH3) 5(H2O)] 3+, followed by (2) slow photoinduced release of NH3 from the aqua complex. This reaction is slow enough for Co(O)OH to form but fast enough so that nanocrystals are small (ca. 3 nm). The alternative dark thermal reaction proceeds much more slowly and produces much larger (~250 nm) polydisperse Co(O)OH aggregates. UV-Vis absorption measurements and ab initio calculations yield a Co(O)OH band gap of 1.7 eV. Fast thermal annealing of Co(O)OH nanocrystals leads to Co3O4 nanocrystals with overall retention of nanoparticle size and morphology. Thermogravimetric analysis shows that oxyhydroxide to mixed-oxide phase transition occurs at significantly lower temperatures (up to T = 64 degrees C) for small nanocrystals compared with the bulk

Isotretinoin and Acne – A Study of Relapses

A study was carried out involving 172 patients with acne which warranted treatment with isotretinoin. Patients were followed up for between 12 and 41 months after discontinuation of treatment and the number of relapses was assessed. 37 patients (21%) relapsed. These relapses were correlated with patients’ age, length of disease progression prior to treatment total dose received daily dose duration of treatment and severity of acne. It appeared that only young age and severity of acne influenced the percentage of relapse.</jats:p

Taking care of our health: research tackling Europe's grand challenge of future health issues

Europeans have never been healthier than they are today. Yet although European countries have experienced a continuous improvement of their overall health situation, our increasing wealth has paradoxically become a driving force of new health problems. Aging and unhealthy lifestyles are leading to new health risks. From an increase in incidence in some non-communicable diseases, to neurodegenerative and mental disorders, we are increasingly faced with new types of ‘maladies of prosperity’. Combined with rising health expectations and technological progress, they also threaten the financial sustainability of our health-care systems. If left unaddressed, these trends are likely to evolve into the health crises of tomorrow. To tackle these challenges, the report argues for increasing research on costly diseases, personalization of treatments, targeted and cost-reducing innovations, health inequalities and sustainability of health-care systems. Our report is complemented by a GeoRisQ Monitor, which assesses the health challenges affecting European countries. It does so by taking a closer look at how these countries fare with respect to three risk factors: (i) Unhealthy Lifestyles; (ii) Aging; and, (iii) Environmental Degradation. The Monitor can be accessed by clicking here

Study of lipoprotein particles LpAI and LpAI:AII in patients before coronary bypass surgery

Abstract Lipids, apolipoproteins, and LpAI and LpAI:AII particles were studied in 43 men (mean age 51, SD 7, years) 24 h before their coronary bypass surgery and in 54 control men (mean age 46 SD 9, years). LpAI and LpAI:AII were analyzed by electroimmunodiffusion and by a noncompetitive enzyme-linked immunoassay, respectively. Concentrations of LpAI and LpAI:AII in the bypass patients were significantly lower (P less than 0.001) than those in the controls. Apolipoprotein AI was significantly correlated with LpAI (P less than 0.001) and LpAI:AII (P less than 0.01) in controls, but only with LpAI:AII (P less than 0.001) in bypass patients. Discriminant analysis between controls and patients showed apolipoprotein AI to be the most powerful discriminant factor; the addition of LpAI and LpAI:AII did not improve discriminant power. We conclude that the determination of LpAI and LpAI:AII particles reflects metabolic disorders in patients but does not significantly influence the discrimination of such patients into risk groups.</jats:p