A hybrid enzyme-nanoparticle system is described for achieving clean reduction of CO 2 to CO using visible light as the energy source. An aqueous dispersion of TiO 2 nanoparticles modified by attachment of carbon monoxide dehydrogenase (CODH) and a Ru photosensitizer produces CO at a rate of 250 μmol CO (g TiO 2 ) -1 h -1 when illuminated with visible light at pH 6 and 20 °C.There is wide interest in converting the greenhouse gas CO 2 into organic molecules by chemical routes 1,2 and a highly desirable goal is to use solar energy to reduce CO 2 to CO, efficiently and cleanly. Carbon monoxide is the feedstock for various synthetic processes, such as the dmetal catalyzed Fischer-Tropsch (production of hydrocarbons), Monsanto and Cativa (both acetic acid) processes. Carbon monoxide also has significant fuel value (Δ c H° = −283.0 kJ mol -1 ), and can readily be converted into methanol (e.g., by the CuO/ZnO/Al 2 O 3 -catalyzed (Fig. S1), CO 2 photo-reduction using natural sunlight (Fig. S2), effect of centrifuging particles and exchanging buffer solution (Fig. S3), effect of pH (Fig. S4), UV-visible study of CODH I adsorption onto TiO 2 nanoparticles (Fig. S5), effect of initial CO concentration (Fig. S6), approximate calculation for CODH I loading on TiO 2 nanoparticles, full list of authors for ref. 12 . This material is available free of charge via the Internet at

A model system for photoreduction of CO 2 to CO using visible light has been extensively studied, using a catalyst for which the CO 2 /CO reaction is electrochemically reversible. The hybrid system comprises metal oxide nanoparticles functionalised with the enzyme carbon monoxide dehydrogenase (CODH), and sensitised to visible light using a ruthenium bipyridyl photosensitiser. An anatase/rutile TiO 2 mixture (Evonik Degussa P25) was selected as the most suitable semiconductor, and CO production rates and stability were examined as a function of each component (photosensitiser, enzyme and TiO 2 ). Tolerance to O 2 and effects of different electron donors were also investigated, together with strategies to control enzyme binding at the surface of TiO 2 in order to enhance overall activity.

Objectives: to evaluate orthogeriatric and nurse-led fracture liaison service (FLS) models of post-hip fracture care in terms of impact on mortality (30 days and 1 year) and second hip fracture (2 years).Setting: Hospital Episode Statistics database linked to Office for National Statistics mortality records for 11 acute hospitals in a region of England.Population: patients aged over 60 years admitted for a primary hip fracture from 2003 to 2013.Methods: each hospital was analysed separately and acted as its own control in a before–after time-series design in which the appointment of an orthogeriatrician or set-up/expansion of an FLS was evaluated. Multivariable Cox regression (mortality) and competing risk survival models (second hip fracture) were used. Fixed effects meta-analysis was used to pool estimates of impact for interventions of the same type.Results: of 33,152 primary hip fracture patients, 1,288 sustained a second hip fracture within 2 years (age and sex standardised proportion of 4.2%). 3,033 primary hip fracture patients died within 30 days and 9,662 died within 1 year (age and sex standardised proportion of 9.5% and 29.8%, respectively). The estimated impact of introducing an orthogeriatrician on 30-day and 1-year mortality was hazard ratio (HR) = 0.73 (95% CI: 0.65–0.82) and HR = 0.81 (CI: 0.75–0.87), respectively. Following an FLS, these associations were as follows: HR = 0.80 (95% CI: 0.71–0.91) and HR = 0.84 (0.77–0.93). There was no significant impact on time to second hip fracture.Conclusions: the introduction and/or expansion of orthogeriatric and FLS models of post-hip fracture care has a beneficial effect on subsequent mortality. No evidence for a reduction in second hip fracture rate was found.