Impact of Gastrostomy Placement on Nutritional Status, Physical Health, and Parental Well-Being of Females with Rett Syndrome: A Longitudinal Study of an Australian Population

© 2018 Elsevier Inc. Objectives: To evaluate how age-related trends in nutritional status, physical health, and parental well-being in females with Rett syndrome may be related to gastrostomy placement and to examine the impact of the procedure on mortality. Study design: We included 323 females from the Australian Rett Syndrome Study and analyzed their demographic, genetic, and child and parental health data collected from over 6 waves of follow-up questionnaire between 2000 and 2011. We used mixed-effects models to estimate the association between repeated measures of outcomes and age, gastrostomy placement and their interaction and Cox proportional hazards regression models to estimate relative risks of mortality for individuals with gastrostomy. Results: Nearly one-third (30.3%) of the cases underwent gastrostomy placement. Nutritional status based on weight, height, and body mass index (BMI) improved over time, and BMI was greater in individuals with gastrostomy placement than in those without (adjusted β = 0.87, 95% CI 0.02-1.73). There was no association between gastrostomy placement and individual's physical health outcomes or parental physical and mental health, nor did the age trend of these outcomes vary by gastrostomy insertion status. Nevertheless, among those at risk of suboptimal weight, the all-cause mortality rate was greater in those who had gastrostomy placement compared with those who had not (hazard ratio 4.07, 95% CI 1.96-8.45). Conclusion: Gastrostomy placement was associated with improvement in BMI in females with Rett syndrome, but its long-term impact on individuals and their families is unclear

Atomistic origins of high-performance in hybrid halide perovskite solar cells

The performance of organometallic perovskite solar cells has rapidly surpassed that of both conventional dye-sensitised and organic photovoltaics. High power conversion efficiency can be realised in both mesoporous and thin-film device architectures. We address the origin of this success in the context of the materials chemistry and physics of the bulk perovskite as described by electronic structure calculations. In addition to the basic optoelectronic properties essential for an efficient photovoltaic device (spectrally suitable band gap, high optical absorption, low carrier effective masses), the materials are structurally and compositionally flexible. As we show, hybrid perovskites exhibit spontaneous electric polarisation; we also suggest ways in which this can be tuned through judicious choice of the organic cation. The presence of ferroelectric domains will result in internal junctions that may aid separation of photoexcited electron and hole pairs, and reduction of recombination through segregation of charge carriers. The combination of high dielectric constant and low effective mass promotes both Wannier-Mott exciton separation and effective ionisation of donor and acceptor defects. The photoferroic effect could be exploited in nanostructured films to generate a higher open circuit voltage and may contribute to the current-voltage hysteresis observed in perovskite solar cells.Comment: 6 pages, 5 figure

Electronic and Geometric Structures of Rechargeable Lithium Manganese Sulfate Li2Mn(SO4)2 Cathode

Here, we report the use of Li2Mn(SO4)2 as a potential energy storage material and describe its route of synthesis and structural characterization over one electrochemical cycle. Li2Mn(SO4)2 is synthesized by ball milling of MnSO4·H2O and Li2SO4·H2O and characterized using a suite of techniques, in particular, ex situ X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy on the Mn and S K-edges to investigate the electronic and local geometry around the absorbing atoms. The prepared Li2Mn-(SO4)2 electrodes undergo electrochemical cycles to different potential points on the charge−discharge curve and are then extracted from the cells at these points for ex situ structural analysis. Analysis of X-ray absorption spectroscopy (both near and fine structure part of the data) data suggests that there are minimal changes to the oxidation state of Mn and S ions during charge−discharge cycles. However, X-ray photoelectron spectroscopy analysis suggests that there are changes in the oxidation state of Mn, which appears to be different from the conclusion drawn from X-ray absorption spectroscopy. This difference in results during cycling can thus be attributed to electrochemical reactions being dominant at the surface of the Li2Mn(SO4)2 particles rather than in the bulk

Non-intrusive flow diagnostics for unsteady inlet flow distortion measurements in novel aircraft architectures

Inlet flow distortion is expected to play a major role in future aircraft architectures where complex air induction systems are required to couple the engine with the airframe. The highly unsteady distortions generated by such intake systems can be detrimental to engine performance and were previously linked with loss of engine stability and potentially catastrophic consequences. During aircraft design, inlet flow distortion is typically evaluated at the aerodynamic interface plane, which is defined as a cross-flow plane located at a specific upstream distance from the engine fan. Industrial testing currently puts more emphasis on steady state distortions despite the fact that, historically, unsteady distortions were acknowledged as equally important. This was partially due to the limitations of intrusive measurement methods to deliver unsteady data of high spatial resolution in combination with their high cost and complexity. However, as the development of aircraft with fuselage-integrated engine concepts progresses, the combination of different types of flow distortions is expected to have a strong impact on the engine’s stability margin. Therefore, the need for novel measurement methods able to meet the anticipated demand for more comprehensive flow information is now more critical than ever. In reviewing the capabilities of various non-intrusive methods for inlet distortion measurements, Filtered Rayleigh Scattering (FRS) is found to have the highest potential for synchronously characterising multiple types of inlet flow distortions, since the method has the proven ability to simultaneously measure velocity, static pressure and temperature fields in challenging experimental environments. The attributes of the FRS method are further analysed aiming to deliver a roadmap for its application on ground-based and in-flight measurement environments.European Union funding: 88652