Improvement of Infrared Detectors for Tissue Oximetry using Black Silicon Nanostructures

AbstractWe present a nanostructured surface, made of dry etched black silicon, which lowers the reflectance for light incident at all angles. This surface is fabricated on infrared detectors used for tissue oximetry, where the detection of weak diffuse light signals is important. Monte Carlo simulations performed on a model of a neonatal head shows that approximately 60% of the injected light will be diffuse reflected. However, the change in diffuse reflected light due to the change in cerebral oxygenation is very low and the light will be completely isotropic scattered. The reflectance of the black silicon surface was measured for different angels of incident and was fund to be below 10% for angles of incident up to 70o. The quantum efficiency of detectors with the black silicon nanostructures was measured and compared to detectors with a simple anti-reflection coating. The result was an improvement in quantum efficiency for both normal incident light and light incident at 38o

Physical activity attenuates postprandial hyperglycaemia in homozygous TBC1D4 loss-of-function mutation carriers

Funder: Karen Elise Jensens Fond; doi: http://dx.doi.org/10.13039/501100004046Funder: European Foundation for the Study of Diabetes; doi: http://dx.doi.org/10.13039/501100001648Funder: NunaFondenFunder: Danish Diabetes Academy; doi: http://dx.doi.org/10.13039/100015223Funder: Lundbeckfonden; doi: http://dx.doi.org/10.13039/501100003554Funder: Villum Fonden; doi: http://dx.doi.org/10.13039/100008398Funder: Det Frie Forskningsråd; doi: http://dx.doi.org/10.13039/501100004836Funder: Steno Diabetes CenterFunder: Commission for Scientific Research GreenlandFunder: Novo Nordisk Foundation Center for Basic Metabolic Research; doi: http://dx.doi.org/10.13039/501100011747Funder: Medical Research Council GreenlandFunder: Medical Research Council DenmarkAbstract: Aims/hypothesis: The common muscle-specific TBC1D4 p.Arg684Ter loss-of-function variant defines a subtype of non-autoimmune diabetes in Arctic populations. Homozygous carriers are characterised by elevated postprandial glucose and insulin levels. Because 3.8% of the Greenlandic population are homozygous carriers, it is important to explore possibilities for precision medicine. We aimed to investigate whether physical activity attenuates the effect of this variant on 2 h plasma glucose levels after an oral glucose load. Methods: In a Greenlandic population cohort (n = 2655), 2 h plasma glucose levels were obtained after an OGTT, physical activity was estimated as physical activity energy expenditure and TBC1D4 genotype was determined. We performed TBC1D4–physical activity interaction analysis, applying a linear mixed model to correct for genetic admixture and relatedness. Results: Physical activity was inversely associated with 2 h plasma glucose levels (β[main effect of physical activity] −0.0033 [mmol/l] / [kJ kg−1 day−1], p = 6.5 × 10−5), and significantly more so among homozygous carriers of the TBC1D4 risk variant compared with heterozygous carriers and non-carriers (β[interaction] −0.015 [mmol/l] / [kJ kg−1 day−1], p = 0.0085). The estimated effect size suggests that 1 h of vigorous physical activity per day (compared with resting) reduces 2 h plasma glucose levels by an additional ~0.7 mmol/l in homozygous carriers of the risk variant. Conclusions/interpretation: Physical activity improves glucose homeostasis particularly in homozygous TBC1D4 risk variant carriers via a skeletal muscle TBC1 domain family member 4-independent pathway. This provides a rationale to implement physical activity as lifestyle precision medicine in Arctic populations. Data repository: The Greenlandic Cardio-Metabochip data for the Inuit Health in Transition study has been deposited at the European Genome-phenome Archive (https://www.ebi.ac.uk/ega/dacs/EGAC00001000736) under accession EGAD00010001428. Graphical abstract