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1. Adiabatic light guide with S-shaped strips

   https://doi.org/10.1063/5.0218512  

   Wojtsekhowski, B; Brash, E J; Franklin, G B; Rosso, A; Sarty, A; Shahinyan, A; Zimmerman, E (October 2024, Review of Scientific Instruments)

   A light guide is an essential part of many scintillator counters and light collection systems. Our main interest is a light guide for a thin, wide scintillator that has high light transmission while converting the area of the light source to the shape of a photo-detector. We propose a variation of the light guide that avoids a 90° twist of the strips, reduces the length of the light pipe, and reduces the complexity of production. Detailed Monte Carlo simulation studies have been performed for a three-strip S-shaped light-guide system. 

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2. Costs and Limitations of Marine Synechococcus Blue-Green Chromatic Acclimation

   https://doi.org/10.3389/fmars.2021.689998  

   Lovindeer, Raisha; Abbott, Lawrence; Medina, Hannah; Mackey, Katherine R. (September 2021, Frontiers in Marine Science)

   Benefits and trade-offs of blue/green chromatic acclimation (CA4) have received limited study. We investigated the energetic costs associated with executing chromatic acclimation using a fluorescence-based calculation of light use efficiency. Using laboratory cultures and artificial light environments, we show that the delayed response to acclimation known to occur in marine Synechococcus acclimating strains (generalists) in green light do not reduce light use efficiency in green light, but that only one generalist, RCC307, with a much smaller range of acclimation, had higher light use efficiency than blue and green light specialist strains. Generalists with a wider acclimation range either had the same or >30% lower light use efficiencies in blue and green light environments. From this work, we propose that advantages from CA4 may not be geared at direct competition with other Synechococcus specialists with fixed pigment types, but may serve to expand the ecological range of Synechococcus in spectral competition with other genera. As all eight Synechococcus strains tested had higher light use efficiency in green light, regardless of a fixed or flexible light harvesting strategy, we add evidence to the suitability of the Synechococcus genus to greener ocean niches, whether stable, or variable. 

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3. Passive atomic-scale optical sensors for mapping light flux in ultra-small cavities

   https://doi.org/10.1038/s41598-023-32010-y  

   Andričević, Pavao; Sellwood, Elaine L.; Eppes, Martha-Cary; Kook, Myungho; Jain, Mayank (December 2023, Scientific Reports)

   Abstract Understanding light propagation and attenuation in cavities is limited by lack of applicable light sensing technologies. Here we demonstrate the use of light-sensitive metastable states in wide bandgap aluminosilicates (feldspar) as passive optical sensors for high-resolution mapping of light flux. We develop non-destructive, infrared photoluminescence (IRPL) imaging of trapped electrons in cracks as thin as 50 µm width to determine the spatio-temporal evolution of light sensitive metastable states in response to light exposure. Modelling of these data yields estimates of relative light flux at different depths along the crack surfaces. Contrary to expectation, the measured light flux does not scale with the crack width, and it is independent of crack orientation suggesting the dominance of diffused light propagation within the cracks. This work paves way for understanding of how light attenuates in the minutest of cavities for applications in areas as diverse as geomorphology, biology/ecology and civil engineering. 

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4. Gene co-expression regulatory network analysis identifies novel regulators in light signaling pathways in Arabidopsis

   https://doi.org/10.3389/fphbi.2025.1597248  

   Bai, Yanan; Pham, Vinh Ngoc; Huq, Enamul (July 2025, Frontiers in Photobiology)

   Plants have evolved with complex sensory systems to recognize signals from multiple environmental conditions. A light signal is one of the most important environmental factors that regulates not only photomorphogenesis but also the developmental strategy of plants throughout their life cycle. The molecular mechanisms of the light signaling modules and the interactions between light and other environmental signals have been studied extensively. However, to enhance plant growth, particularly in crop production, we need to gain a deeper understanding of how light regulates plant development within gene regulatory networks (GRNs). Understanding GRNs is important to identify not only the novel genes and transcription factors in light signaling pathways but also the factors that connect light signaling and other environmental signals. Weighted gene co-expression network analysis (WGCNA) has been used to study GRN. We applied WGCNA to 58 RNA-seq samples of wild-type Arabidopsis grown under different light treatments and built the gene co-expression networks. We identified 14 different modules that are significantly associated with different light treatments. Among them, the honeydew1 and ivory display significant association with the dark-grown seedlings. Many hub genes identified from these modules are significantly enriched in light responses, including responses to red, far-red, blue light, light stimulus, auxin responses, and photosynthesis. Although we found many known transcription factors in these modules, we also identified several unknown genes and transcription factors that are significantly associated with the honeydew1 module and highly differentially expressed between dark and light conditions. To examine whether the hub genes in the honeydew1 module play a role in light signaling, we isolated mutants in selected hub genes and measured hypocotyl lengths under dark, red, and far-red light conditions. These assays showed that four hub genes are involved in regulating light signaling pathways. This study provides a new approach to identifying novel genes in GRNs underlying light responses in Arabidopsis. 

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5. The duration of light exposure differentially affects tidal volume and respiratory frequency in male mice

   Marino, GM; Twining, RR; Arble, DM (November 2025, Society for Neuroscience)

   Respiratory frequency and tidal volume exhibit daily, 24-hr rhythms in human and rodent models. Environmental light has emerged as a potential modulator of ventilatory rhythmicity, as mice lacking intrinsically photosensitive retinal ganglion cells fail to alter their breathing in response to light. Despite this evidence, it remains unknown how the duration of light exposure influences breathing in mice. To assess the effects of light exposure on breathing, male wild-type mice (n = 8) were exposed to broad-spectrum white light (~450 lux) in the standard dark phase, either for 3h (ZT 13-16) or for 5 minutes (ZT13-13.05). Respiratory measures were assessed for 36 hours using whole-body plethysmography. To determine whether the light manipulation produced significant deviations from expected respiratory patterns, a nonparametric, within-subjects bootstrapping approach was conducted in R. This compared parallel time points between a predefined test period and the equivalent control period without a light manipulation. We found that a 3h light stimulus administered during the standard dark phase reduced tidal volume and respiratory frequency for ~80 minutes during light exposure. Immediately following the offset of the 3h stimulus, respiratory frequency was increased for 2h compared to control. While statistical analysis is currently ongoing, a 5-minute light stimulus appeared to decrease both tidal volume and respiratory frequency during light exposure. In contrast to a 3hr stimulus, both tidal volume and respiratory frequency were increased at 90 minutes following the offset of the 5-minute light stimulus. While preliminary, these data suggest that tidal volume and respiratory frequency differentially respond to the duration of environmental light exposure. Subsequent research is required to determine if tidal volume is specifically responsive to shorter light durations and the extent to which a 3h light stimulus may be “masking” the tidal volume response. This work expands upon our current understanding of respiratory physiology to include light duration as a key variable affecting daily breathing 

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