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Background: A multimodal conservative approach (MCA) is internationally recommended prior to bariatric surgery for the majority of patients. This research aimed to identify risk factors for therapy failure within the MCA., Methods: This study was conducted in a German bariatric obesity centre. Patients who underwent a 3- to 6-month preoperative MCA from November 2019 to October 2020 were prospectively recorded and analysed. MCA included dietary and movement therapy, psychological and endocrinological referral and connection to a patient support group. The change in BMI was considered the main parameter for therapeutic success. Explanatory factors were evaluated for this outcome of interest and included physical and mental well-being (SF-36), perceived stress (DASS-21), social and economic situation and educational background (SOEP)., Results: Out of 413 eligible patients, 209 were analysed. Overall, patients gained BMI (average gain 0.23 kg/m² (s.d. 1.44 kg/m²)) during the preoperative MCA. Diverse social, demographic and economic and health properties did not influence the course of the therapy. There was a significant positive correlation between successful loss of BMI and physical well-being (β = 0.03, 95% c.i. 0.01 to 0.04, P < 0.0001) and a negative correlation between mental well-being (β = -0.02, 95% c.i. -0.004 to -0.001, P = 0.001) as well as self-perceived stress (β = -0.05, 95% c.i. -0.09 to -0.01, P = 0.019), although these effects were small and did not affect the overall trend of gaining BMI during MCA., Conclusion: The current therapeutic approach of preoperative conservative treatment within the multimodal concept of bariatric treatment fails to achieve its intended outcome. A different conservative weight loss programme from the pre-bariatric setting, which should focus on a surgical preparation, is therefore recommended., (© The Author(s) 2024. Published by Oxford University Press on behalf of BJS Foundation Ltd.)

Recent attempts to improve solar cell performance by increasing their spectral absorption interval incorporate up-converting fluorescent nanocrystals on the structure. These nanocrystals absorb low energy light and emit higher energy photons that can then be captured by the solar cell active layer. However, this process is very inefficient and it needs to be enhanced by different strategies. In this work, we have studied the effect of nanostructuration of perovskite thin films used in the fabrication of hybrid solar cells on their local optical properties. The perovskite surface was engraved with a focused ion beam to form gratings of one-dimensional grooves. We characterized the surfaces with a fluorescence scanning near-field optical microscope, and obtained maps showing a fringe pattern oriented in a direction parallel to the grooves. By scanning structures as a function of the groove depth, ranging from 100 nm to 200 nm, we observed that a 3-fold luminescence enhancement could be obtained for the deeper ones. Near-field luminescence was found to be enhanced between the grooves, not inside them, independent of the groove depth and the incident polarization direction. This indicates that the ideal position of the nanocrystals is between the grooves. In addition, we also studied the influence of the inhomogeneities of the perovskite layer and we observed that roughness tends to locally modify the intensity of the fringes and distort their alignment. All the experimental results are in good agreement with numerical simulations., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Knowing the temperature distribution within the conducting walls of various multilayer-type materials is crucial for a better understanding of heat-transfer processes. This applies to many engineering fields, good examples being photovoltaics and microelectronics. In this work we present a novel fluorescence technique that makes possible the non-invasive imaging of local temperature distributions within a transparent, temperature-sensitive, co-doped Er:GPF1Yb0.5Er glass-ceramic with micrometer spatial resolution. The thermal imaging was performed with a high-resolution fluorescence microscopy system, measuring different focal planes along the z -axis. This ultimately enabled a precise axial reconstruction of the temperature distribution across a 500-µm-thick glass-ceramic sample. The experimental measurements showed good agreement with computer-modeled heat simulations and suggest that the technique could be adopted for the spatial analyses of local thermal processes within optically transparent materials. For instance, the technique could be used to measure the temperature distribution of intermediate, transparent layers of novel ultra-high-efficiency solar cells at the micron and sub-micron levels.