Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Author: search.filters.author.Didikoğlu, AltuğDepartment: search.filters.department.Izmir Institute of Technology

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  • Article
    Citation - WoS: 5
    Citation - Scopus: 6
    Beyond Lux: Methods for Species and Photoreceptor-Specific Quantification of Ambient Light for Mammals
    (Bmc, 2024) McDowell, Richard J.; Didikoğlu, Altuğ; Didikoglu, Altug; Woelders, Tom; Gatt, Mazie J.; Moffatt, Finn; Notash, Saba; Lucas, Robert J.
    BackgroundLight is a key environmental regulator of physiology and behaviour. Mistimed or insufficient light disrupts circadian rhythms and is associated with impaired health and well-being across mammals. Appropriate lighting is therefore crucial for indoor housed mammals. Light is commonly measured in lux. However, this employs a spectral weighting function for human luminance and is not suitable for 'non-visual' effects of light or use across species. In humans, a photoreceptor-specific (alpha-opic) metrology system has been proposed as a more appropriate way of measuring light.ResultsHere we establish technology to allow this alpha-opic measurement approach to be readily extended across mammalian species, accounting for differences in photoreceptor types, photopigment spectral sensitivities, and eye anatomy. We develop a high-throughput method to derive spectral sensitivities for recombinantly expressed mammalian opsins and use it to establish the spectral sensitivity of melanopsin from 13 non-human mammals. We further address the need for simple measurement strategies for species-specific alpha-opic measures by developing an accessible online toolbox for calculating these units and validating an open hardware multichannel light sensor for 'point and click' measurement. We finally demonstrate that species-specific alpha-opic measurements are superior to photopic lux as predictors of physiological responses to light in mice and allow ecologically relevant comparisons of photosensitivity between species.ConclusionsOur study presents methods for measuring light in species-specific alpha-opic units that are superior to the existing unit of photopic lux and holds the promise of improvements to the health and welfare of animals, scientific research reproducibility, agricultural productivity, and energy usage.
  • Article
    Citation - WoS: 33
    Citation - Scopus: 30
    Associations Between Light Exposure and Sleep Timing and Sleepiness While Awake in a Sample of Uk Adults in Everyday Life
    (Natl Acad Sciences, 2023) Didikoglu, Altug; Mohammadian, Navid; Johnson, Sheena; van Tongeren, Martie; Wright, Paul; Casson, Alexander J.; Lucas, Robert J.; Didikoğlu, Altuğ
    Experimental and interventional studies show that light can regulate sleep timing and sleepiness while awake by setting the phase of circadian rhythms and supporting alertness. The extent to which differences in light exposure explain variations in sleep and sleepiness within and between individuals in everyday life remains less clear. Here, we establish a method to address this deficit, incorporating an open- source wearable wrist -worn light logger (SpectraWear) and smartphone-based online data collection. We use it to simultaneously record longitudinal light exposure (in melanopic equivalent daylight illuminance), sleep timing, and subjective alertness over seven days in a convenience sample of 59 UK adults without externally imposed circadian challenge (e.g., shift work or jetlag). Participants reliably had strong daily rhythms in light exposure but frequently were exposed to less light during the daytime and more light in pre- bedtime and sleep episodes than recommended [T. M. Brown et al., PLoS Biol. 20, e3001571 (2022)]. Prior light exposure over several hours was associated with lower subjective sleepiness with, in particular, brighter light in the late sleep episode and after wake linked to reduced early morning sleepiness (sleep inertia). Higher pre- bedtime light exposure was associated with longer sleep onset latency. Early sleep timing was correlated with more reproducible and robust daily patterns of light exposure and higher daytime/lower night -time light exposure. Our study establishes a method for collecting longitudinal sleep and health/performance data in everyday life and provides evidence of associations between light exposure and important determinants of sleep health and performance.