Photochemistry and Photobiology

PurposeTo evaluate the retinal safety of repeated low-level red-light (RLRL) therapy using the Eyerising Myopia Management Device (EMMD) by analysing exposure parameters relative to established thermal and photochemical retinal injury thresholds and empirical human exposure data. MethodsEmission characteristics of the EMMD were measured in an accredited laboratory under worst-case conditions. Parameters assessed included wavelength, intraocular power, corneal irradiance, and retinal image characteristics across accommodative states. These measurements were compared with international safety standards, maximum permissible exposure limits, and experimentally derived retinal injury thresholds from animal studies and validated computational models. The effects of repeated exposures from RLRL therapy using the EMMD were evaluated using photochemical additivity principles and repair kinetics, and further contextualised using human volunteer exposure data. ResultsThe EMMD emitted red laser radiation at 654-655 nm with a maximum intraocular power of approximately 1 mW through a 7 mm pupil, placing it within Class 3R and marginally above the Class 2 limit. Corneal irradiance was approximately 26 W m- 2, well below conservative photochemical exposure limits. Thermal injury modelling indicated retinal damage thresholds above device exposure, including under worst-case assumptions of minimal retinal image size and absence of eye movements. Accounting for repeated daily exposures and photochemical additivity, safety margins remained approximately 3-fold for a 7 mm pupil and approximately 8-fold for a more realistic 4 mm pupil. Human volunteer studies demonstrated no detectable structural or functional retinal injury at exposure levels approximately five times higher than those produced by the EMMD. ConclusionExposure parameters of RLRL therapy using the EMMD remain well below conservative retinal injury thresholds under prescribed use conditions. Integration of experimental, modelling, and human data indicates substantial safety margins, supporting its safe clinical use.

Germicidal UV devices offer a promising solution to mitigate surface-mediated pathogen transmission, providing effective disinfection without material corrosion. This study evaluated the surface inactivation kinetics of two bacteria and two bacteriophages using a low-pressure (LP) mercury UV lamp (254 nm) and a filtered krypton chloride (KrCl*) excimer lamp (222 nm). Three deposition methods (Spray, Spread, and Pipette) and two extraction methods (Swab and Elute) were compared. The UV dose response on surfaces followed a two-region non-linear model due to shielding from dried deposition constituents, primarily through UV absorption. KrCl* excimer exhibited similar bacterial inactivation but slightly lower viral inactivation than LP UV lamp (maximum inactivation [~] 1 log lower), but its safety profile makes it compelling in occupied spaces. Compared to aqueous conditions, bacteria were more UV sensitive on surfaces, whereas viruses were more resistant. The deposition methods affected the inactivation results, with the Spray method resulting in higher bacteria inactivation. While the extraction methods had limited effect on inactivation efficacy, the Swab method provided higher inactivation detection limits ([~] 2 log higher) and more consistent extraction efficiency. This study provides mechanistic insights into the effects of deposition conditions, UV wavelengths, and microbial characteristics on UV surface disinfection and contributes to standardization of testing methods. TOC Graphic O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=104 SRC="FIGDIR/small/734141v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@11db511org.highwire.dtl.DTLVardef@15aa3faorg.highwire.dtl.DTLVardef@1c39ac9org.highwire.dtl.DTLVardef@e726ed_HPS_FORMAT_FIGEXP M_FIG C_FIG

Germline pathogenic or likely pathogenic variants (GPVs) in BRCA-1 Associated Protein 1 (BAP1) are associated with a spectrum of tumors, including uveal melanoma (UM). Currently, UM patients with BAP1 GPVs are treated as high-risk class 2 tumors based on mostly empiric data. In the current study, we examined the clinical phenotype of a cohort of 29 UM patients with BAP1 GPVs. We also carried out a systematic review of the literature of UM patients with BAP1 GPVs. We observed that UM patients with BAP1 GPVs have significantly lower median age of diagnosis compared to median age reported in UM patients in the Surveillance, Epidemiology, and End Results Program (SEERS) database. Metastatic risk and overall survival in the UM BAP1 GPVs cohort were statistically significant from those in patients with class 1 tumors, but were comparable to those observed in UM patients with class 2 tumors. In UM BAP1 GPVs treated with radiation (n=12), no secondary cancers were observed in the field of radiation in a median 26.5 months (range, 4-119 months) follow up period. One patient experienced a separate growth of UM at a distinct location within the same eye. These data support managing UM in patients with BAP1 GPVs as aggressive class 2 tumors, following the currently established standard of care for these high-risk tumors.

BackgroundDural defects, either from trauma, tumor resection, surgical approaches, genetics, or spontaneously represent a significant clinical challenge in neurosurgery. Given the established efficacy of riboflavin-sensitized ultraviolet-A (UVA) photo-crosslinking in ophthalmology, this study investigated its feasibility and dose-response characteristics as a novel strategy to biochemically augment the mechanical integrity and strength of ex-vivo bovine dura mater. MethodsForty bovine dura mater specimens were treated ex vivo using riboflavin concentrations of 2, 4, or 8 mM combined with UVA irradiation at 0.3 or 3 mW/cm{superscript 2}. PBS-treated specimens exposed to UVA served as controls. Atomic force microscopy nanoindentation was used to measure the local elastic modulus in matched regions before and after treatment, enabling paired assessment of treatment-induced mechanical changes while minimizing inter-sample variability. Post-treatment stiffness, fold-change from baseline, and riboflavin dose-response relationships were analyzed statistically. ResultsBaseline elastic moduli were equivalent across all groups (mean approximately 52 kPa, p=0.92). While UVA alone caused a modest approximately 2- to 3-fold stiffness increase, riboflavin-UVA treatment produced a dramatic, concentration-dependent effect. The highest treatment (8 mM RF, 3 mW/cm{superscript 2} UVA) increased the elastic modulus 150-fold, from approximately 53 kPa to approximately 8,000 kPa. Post-UV stiffness exhibited a strong linear relationship with riboflavin concentration (R{superscript 2} = 0.994), indicating a precisely titratable crosslinking effect. All treatment conditions were statistically distinguishable (p < 0.001). ConclusionRiboflavin-sensitized UVA crosslinking substantially increases the nanomechanical strength of ex vivo bovine dura mater in a controllable, dose-dependent manner. These findings establish a proof of concept for biochemical reinforcement of dural tissue that might be used clinically. As a next step evaluation using human dura, macroscopic biomechanical testing, penetration-depth analysis, and safety assessment is warranted.

Bacterial survival after ultraviolet (UV) exposure is shaped not only by the extent of DNA damage but also by the physiological state-dependent capacity for DNA repair. Here, we examined the mechanisms underlying growth phase-dependent UV resistance in Escherichia coli K-12 exposed to 262 nm UV irradiation. Stationary-phase cells required higher UV fluence for log inactivation than exponential-phase cells, whereas the levels of UV-induced DNA damage, assessed by cyclobutane pyrimidine dimer staining and real-time PCR, did not differ markedly between the two growth phases. Deletion of nucleotide excision repair (NER) genes, including uvrA, uvrB, uvrC, and uvrD, markedly reduced survival after UV irradiation, indicating that NER is essential for the high UV resistance of stationary-phase cells. Quantitative real-time reverse transcription PCR showed stronger UV-induced expression of several DNA repair and UV resistance genes, including uvrA, uvrB, cho, umuC, and umuD, in stationary-phase cells than in exponential-phase cells. Furthermore, deletion of the DNA cytosine methyltransferase gene dcm increased UV resistance and enhanced the expression of uvrB, cho, umuC, umuD, and sulA in stationary-phase cells. These findings suggest that DNA cytosine methylation modulates UV resistance in E. coli, at least in part by influencing NER- and SOS-associated gene expression.

Ionizing radiation induces molecular responses that may be used to estimate exposure when physical dosimeters are unavailable. Here we present two large-scale proteomics datasets generated from mouse dorsal skin punch samples collected following controlled X-ray exposures spanning multiple doses, dose rates, and post-exposure time points. Experiment 1 comprised 96 samples (including 16 reference samples) collected 6 days after exposure to 0-75 cGy delivered at either 30 or 300 cGy/min. Experiment 2 comprised 936 samples (including 236 reference samples) exposed to 0-100 cGy at either 3 or 28 cGy/min dose rates and harvested between 7 and 150 days post-exposure. All samples were processed using a standardized workflow involving automated bead-based digestion and data-independent acquisition mass spectrometry. The datasets include multiple pooled reference sample types, process controls, and system suitability standards ensuring high quality data. All data presented are available via ProteomeXchange at several levels of processing, from raw files through normalized peptide- and protein-level abundance matrices suitable for biomarker discovery and machine learning applications. This dataset will facilitate generation of new insights into the biological changes and molecular signatures resulting from X-ray exposure in mice and may also help inform future studies in humans.

Human skin colors occupy a characteristic banana-shaped region in CIE L*a*b* space, but why skin color coordinates are restricted to this region and how they relate to melanin and blood remain incompletely understood. We developed a physics-based framework linking skin chromophore content to colorimeter-derived skin color coordinates using two complementary three-layer light transport models. Across physiologic ranges of epidermal melanosome volume fraction and dermal blood volume fraction, simulated reflectance spectra were converted to CIE L*a*b* coordinates and compared with human skin color measurements from the International Skin Spectra Archive. Physiologic variation in melanin and blood reproduced the observed banana-shaped locus and revealed distinct chromophore-specific trajectories. Iso-melanin trajectories became progressively more linear as melanin increased, whereas iso-blood trajectories retained the curvature of the skin color locus. As melanin increased, perceptible color differences from blood volume changes were reduced, providing a mechanistic explanation for reduced erythema visibility in highly pigmented skin. These relationships were stable across plausible variations in layer thickness and tissue oxygenation and agreed with external validation data. The framework also identified when the Individual Typology Angle is confounded by blood or distorted by dermal melanin. Together, these findings establish a mechanistic optical basis for interpreting colorimeter-derived skin color coordinates.

Background: A subset of uveal melanomas can be treated using either enucleation or proton beam therapy (PBT), which offer similar oncological outcomes. The most appropriate treatment depends on a patient's preference. To allow patients to genuinely determine their preference, it is recommended to describe options as neutrally as possible. This study assesses to what extent ocular oncologists use and perceive non-neutral framing behaviour, and if it is related to patient satisfaction with decision-making. Methods: Consultations of ocular oncologists with patients newly-diagnosed with uveal melanoma were audio recorded, transcribed verbatim, and coded for ocular oncologists' explicit and implicit non-neutral framing behaviours. Explicit non-neutral framing was defined as: explicitly mentioning a preferred option at least once, without relating it to the patient. Implicit non-neutral framing was defined as: describing an option (un)favourably, without providing a medically substantive clarification alongside. Results: 110 patients provided consent for the audio recordings. Non-neutral framing was found in 84% (n=92/110) of consultations. We found explicit behaviour in 38% (42/110) and implicit behaviour in 76% (84/110, median=1, range, 0-4) of consultations. The most frequent implicit framing was presenting options by positively or negatively emphasizing one option. Non-neutral framing behaviours were not significantly related to patient satisfaction with decision-making. Conclusion: This study shows that in most consultations some non-neutral framing was present, which did not impact patients' satisfaction with decision-making. Nonetheless, ocular oncologists should be aware that how they describe options may influence preferences in ways that do not align with the patient's values.

ObjectiveOnly preliminary investigations on the use of the 445 nanometer wavelength blue light laser (BLL) for various laryngeal pathologies have been described. Currently, no standard exists for reporting treatment technique and tissue effect with this modality. Here, we aim to establish and validate a classification system to describe laser-induced tissue effects. Study DesignRetrospective video-based study for classification development and reliability validation. MethodsVideo recordings from procedures performed with the BLL by multiple academic laryngologists were retrospectively reviewed. A preliminary 6-point classification (BLL 1-6) was developed based on expert consensus. Thirteen additional procedural clips were independently rated utilizing the classification schema to assess perceived tissue effect, and measure inter- and intra-rate reliability. ResultsThe final 5-point classification system (BLL 1-5) included angiolysis, blanching, tissue vaporization, ablation with mechanical tissue removal, and cutting. The consensus of the combined reviewers in rating all cases was 89% (58 of 65). Complete consensus was not achieved in 11% (7/65) of cases. Of those incorrect, 57% (4/7) were of clips illustrating the BLL-2 classification. Intra-rater reliability amongst the reviewers was 100%. ConclusionTissue effect of the 445 nm blue light laser can reliably be standardized with this proposed classification system. This rating system can be used to facilitate future systematic study of outcomes and effective communication between laryngologists and trainees.

Ionizing radiation induces DNA damage and oxidative stress; however, the genes and molecular mechanisms involved in bacterial stress responses have not been sufficiently identified. In this study, we used Limnobacter thiooxidans strain CS-K2, which is the closest relative to the bacteria detected in torus room water at the Fukushima Daiichi Nuclear Power Plant according to 16S rRNA gene sequences, and evaluated its response to {gamma}-ray irradiation using integrated transcriptomic and proteomic analyses. We identified three previously uncharacterized genes (LT3105, LT3115, and LT3126) that were strongly induced at the mRNA and protein levels. These genes exhibited low basal expression but were markedly upregulated by {gamma}-ray irradiation. Notably, LT3126 encodes a protein containing VIT (vault protein inter--trypsin) and VWA (von Willebrand factor type A) domains and showed the strongest induction. Overexpression of LT3126 increased survival after 500 Gy irradiation by approximately 200-fold compared with the control bacteria, demonstrating a direct contribution to survival under high-dose stress. Comparative genomic analysis showed that these genes are not widely conserved across bacteria but are unevenly distributed among specific lineages. Taken together, this study identified a novel set of {gamma}-ray-responsive genes and demonstrated a functional role for LT3126 in radiation resistance, providing new insights into molecular adaptation in radiation-associated environments. IMPORTANCEWe identified a novel set of {gamma}-ray-responsive genes (LT3105, LT3115, and LT3126) in the non-model bacterium Limnobacter thiooxidans. These genes are located in relatively close genomic proximity and are coordinately induced upon irradiation, suggesting a shared functional role in stress response. Overexpression of LT3126 increased survival by approximately 200-fold after 500 Gy irradiation compared with the control bacteria, demonstrating a substantial contribution to survival under high-dose stress. These genes were also induced by heat shock and oxidative stress, indicating that their function extends beyond radiation-specific responses to broader environmental stress adaptation. Consistent with this, comparative genomic analysis showed that these genes are not widely conserved across bacteria but are unevenly distributed among specific lineages. Taken together, these findings highlight previously unrecognized molecular strategies that may support bacterial survival in radiation-associated environments.

PurposeAssessing visual function in patients with ultralow vision (ULV), particularly those with retinitis pigmentosa (RP), remains a significant challenge in therapeutic development. Full-field stimulus test (FST) provides a quantitative measure of retinal light sensitivity and may serve as a valuable clinical endpoint. We investigated FST in ULV RP by examining its associations with functional measures and daily activity-based tasks. DesignObservational, cross-sectional study. ParticipantsPatients with RP and visual acuity in the worse-seeing eye below counting fingers (CF) were enrolled. MethodsAfter dilation and 45-minute dark adaptation, FST was performed monocularly with brief full-field white-light flashes across three visits. Visual acuity was classified into four groups: no light perception (NLP), light perception (LP), hand motion (HM), and CF or better. We assessed functional vision using two tabletop object-recognition and exploration tasks, two mobility tasks, and three vision-related questionnaires. FST thresholds were compared across visual acuity groups, and associations with functional outcomes were analyzed. Main Outcome MeasuresFST thresholds and their associations with functional vision outcomes. ResultsThirty-five patients (70 eyes; median age, 62 years, range 39-84) were included. Median FST thresholds (log cd*s/m{superscript 2}) by visual acuity group were as follows: NLP, 1.13 (-0.63-2.54); LP, -0.27 (-2.70-2.91); HM, -1.13 (-6.24-0.51); CF or better, -2.82 (-5.67- -1.73) (p < 0.001). Measurable FST thresholds were obtained in 9 of 14 NLP eyes (64.3%). FST thresholds showed significant correlations with tabletop performance (r = -0.70 to - 0.46) and mobility performance (r = -0.65), whereas no significant association was observed with questionnaire scores. Test-retest variability across three visits showed no systematic bias, with a coefficient of repeatability of {+/-}0.66 to {+/-}0.82 log cd{middle dot}s/m{superscript 2}. ROC analyses identified FST cutoffs of -1.75 to -0.87 log cd{middle dot}s/m{superscript 2} at which patients first achieved nonzero functional task performance. ConclusionsFST quantifies residual visual function in ULV RP and correlates strongly with performance-based measures of functional vision in daily life. These findings support FST as a clinically meaningful endpoint for therapeutic trials in advanced RP and other severe visual impairments and highlight the value of anchoring FST thresholds to functional task performance.

Agriphotovoltaics (APV) combines crop production with solar energy generation to address increasing demands for food and energy while reducing land-use competition. Unlike conventional opaque photovoltaic systems, semitransparent organic photovoltaics (OPVs) selectively absorb light, potentially improving efficiency but also altering both light quantity and spectral quality, key factors affecting plant growth. Here, we developed a rapid bioassay based on hypocotyl elongation to evaluate plant responses to OPV-filtered light using Arabidopsis thaliana and Cardamine hirsuta, two species with contrasting shade strategies. Screening a diverse set of OPV materials revealed that plant growth responses depend more on spectral composition than on total light intensity alone. Certain materials, such as PTB7-Th and D18, produced growth patterns similar to neutral shading, while others promoted elongation. Our analyses identified blue light wavelengths, linked to cryptochrome activity, as more critical than red light wavelengths, linked to phytochrome activity, for maintaining normal development. These findings provide a scalable framework to assess OPV-plant compatibility and demonstrate that optimizing spectral quality alongside light intensity is essential for designing efficient APV systems that sustain crop performance while generating renewable energy.

ObjectiveTo evaluate outcomes of lower-energy selective laser trabeculoplasty (SLT) using a titrated energy-pigmentation (TAPE) construct. MethodsThis retrospective study analyzed de-identified clinical data of 62 eyes undergoing lower-energy SLT as part of routine care. Laser energy was titrated relative to trabecular meshwork (TM) pigmentation grade and quantified as the product of the two (TAPE score). For example, grade 2 pigmentation x 40 mJ total energy yields a TAPE score of 80. The primary outcome was intraocular pressure (IOP) at 2 months, with adjustment for baseline maximum IOP (Tmax) using analysis of covariance (ANCOVA). Durability was assessed using Kaplan-Meier survival analysis and Cox proportional hazards modeling. ResultsAfter adjustment for baseline Tmax, higher TAPE scores ([&ge;]70) were associated with lower 2-month IOP (p < 0.01) and greater likelihood of achieving [&ge;]20% IOP reduction. Over longer follow-up, higher TAPE scores were associated with fewer treatment escalation events and improved survival free of additional therapy. Low-grade anterior chamber inflammation was common, transient, and self-limited. At 3 years, 85% of eyes in the high-TAPE group remained drop-free, accounting for retreatment where applicable. No clinically significant IOP spikes or sight-threatening adverse events were observed. ConclusionsHigher energy-pigmentation (TAPE) scores were associated with improved short-term IOP reduction and greater durability following lower-energy SLT. These findings are hypothesis-generating and suggest that TM pigmentation-adjusted energy delivery may enhance biologic engagement of the trabecular outflow pathway and support prospective evaluation of individualized SLT dosing strategies.

Under natural growth conditions, plants are not usually exposed to the high-energy ultraviolet C range (UV-C, 100-280 nm) of the solar spectrum, as this is absorbed by the ozone layer. However, low doses of UV-C radiation can trigger stress responses in plants. Nevertheless, it is not yet fully understood how UV-C light affects plant development at the hormonal level. Here we show that a single one-min UV-C light pulse (20 W/m2) alters gibberellin (GA) homeostasis in Arabidopsis in two phases: initially, the level of GA12 - a key precursor of the final part of gibberellin biosynthesis - is reduced. Consistent with this, the transcript levels of the CPS, KS and KAO2 genes, which encode enzymes involved in the initial parts of gibberellin biosynthesis, decrease. The level of the plant hormone GA4 also decreases initially, probably due to the reduced GA12 precursor levels. However, in a second phase, the endogenous GA4 levels rise in UV-C treated plants relative to control plants. This increase leads to an early onset of flowering, as well as increased growth and fertility, in UV-C-treated Arabidopsis plants. The GA signalling mutant gdella does not exibit wild-type phenotypic responses to UV-C treatment, indicating that GA signalling is essential for the UV-C response. To further narrow down the responsible steps in the GA-signalling pathway, we tested the kao1 and kao2 mutants, which are both impaired in early gibberellin biosynthesis. Neither mutant displays phenotypic responses to the UV-C treatment, indicating that both genes are required for mediating the UV-C response. In contrast, the quintuple 2-oxidase mutant C19--2oxqM exhibits responses to UV-C treatment similar to the wild-type, suggesting that the five catabolic 2-oxidases that act on C19-GAs play a negligible role in regulation GA-hormone levels for growth and development in this case. HighlightUV-C pulse triggers biphasic gibberellin dynamics, delaying early development but ultimately enhancing growth and fertility in Arabidopsis thaliana.

Invertebrate vision relies on bistable visual pigments flipping upon photon absorption between rhodopsin and metarhodopsin states. In living butterflies, the UV-VIS absorption spectra of rhodopsin and metarhodopsin, respectively with 11-cis and all-trans isomers of 3-hydroxy-retinal (A3) chromophore, can be conveniently recorded from the eyeshine, the light reflected from the compound eye after passing twice through the light-guiding rhabdoms. * Here, a microscope coupled with a broadband LED source and a microspectrometer was used to record photorelaxations reported in eyeshine reflection spectra. Fitting temporal exponential relaxations to log-reflectance arrays yielded transient and baseline spectra that are analogous to absorbance difference and sum, respectively. Both types of spectra were subjected to singular value decomposition and to fitting of templated visual pigment absorption spectra. * The compound eye of the high brown fritillary Fabriciana adippe was exposed to a series of second-long broadband light pulses, causing photorelaxations with time constants between 40 and 120 ms that led to 80% metarhodopsin in equilibrium. The transient and baseline spectra were fitted with pigment templates, estimating the alpha peak wavelength 547-552 nm for rhodopsin and 496-501 nm for metarhodopsin. The metarhodopsin to rhodopsin alpha peak absorbance ratio 1.25-1.35 is consistent with the isosbestic wavelength at 530 nm. The second isosbestic wavelength indicates that rhodopsin beta (UV) peak absorbs more strongly than metarhodopsin below 405 nm. * Baseline spectra, which were not explicitly analysed in previous studies, enable concatenation of exposures, monitor long-term changes of pigment, and enhance the estimation of beta peak parameters. * The method can be directly used in many butterflies and could be adapted to other insects, particularly fruitflies, facilitating studies of the relation between the visual pigment spectra and the opsin sequences. Spectroscopic results can be complemented with physiologically measured photoreceptor spectral sensitivity datasets and analysed with the same global fitting procedure.

Understanding plant growth dynamics requires imaging across day-and-night cycles to quantify growth, movement and development in the aerial plant body and to capture the rhythmic nature of these processes. This requires imaging in light during the day and in darkness at night without perturbing plant physiology. Nighttime imaging has typically depended on infrared (IR) illumination, producing monochrome datasets that require specialised hardware and separate analysis pipelines when combined with daytime RGB imaging. Here, we evaluated very low-intensity green (dimG) illumination from standard LEDs as a practical alternative for colour-consistent nighttime imaging and assessed its physiological impact in Arabidopsis thaliana and Lactuca sativa (lettuce). We show that high resolution colour images can be obtained under dimG using low- cost cameras, with sufficient consistency between full-spectrum and dimG images to allow direct comparison and unified image analysis. We show that very low-fluence green light (<0.5 mol m-2 s-1) does not sustain circadian oscillations of gene activity under continuous exposure and does not perturb rhythms when applied during the dark phase of diel cycles. DimG imaging enabled accurate detection of diel leaf movement profiles in Arabidopsis circadian mutants, revealing genotype-specific phase differences under varying photoperiods. In lettuce, dimG pulses and continuous dimG enabled accurate quantification of diel leaf movement without affecting growth, stomatal opening, electron transport rate or chlorophyll content. Motion profiles under continuous dimG mirrored those under darkness. Our findings establish dim green illumination as a cost-effective solution for night-time imaging, simplifying phenotyping workflows with minimal impact on physiology.

We investigate the effects of skin pigmentation and light source characteristics on the performance of reflective Pulse oximetry (PO) devices used in healthcare and well-being applications. We use Monte Carlo (MC) simulations to compare ideal monochromatic and realistic LED spectral emission profiles and tolerance-related wavelength shifts. The simulation covers photon transport in skin models with melanin concentrations (2.55% to 30.5%) and arterial oxygen saturations SaO2 (70% to 100%.) Accuracy was assessed by SpO2 error, root-mean-square error RMSE (Arms), and percentile tail-errors (P90, P95, and P99). Monochromatic spectral emission yielded the lowest SpO2 error (RMSE = 1.32), while LED spectral emission profiles increased errors (RMSE = 2.10). Infrared wavelength tolerances increased SpO2 RMSE by 1.1 {+/-} 0.3. SpO2 error increased with melanin concentration, from underestimation (-1.8 {+/-} 0.1%) at 2.55% melanin concentration to overestimation (+3.9 {+/-} 1.2%) at 30.5% for low SaO2 (70%) and LED spectral emission profiles. At 30.5% melanin concentration, P95 and P99 exceeded FDA and DIN EN ISO 80601-2-61 thresholds, in particular at low SaO2 (70%). Clipping SpO2 estimates at 100% resulted in an apparent RMSE decrease of up to 3%, reflecting error masking rather than real error reduction. In conclusion, LED spectral emission profiles and wavelength tolerances can amplify melanin-related bias in SpO2 estimates. Monochromatic emission and tighter wavelength control can reduce SpO2 error and should be considered in device design and regulation. Regulatory standards should discourage clipping SpO2 estimates at 100% and mandate additional metrics as RMSE fails to reflect clinically critical percentile error thresholds, i.e. P95 and P99.

Organisms have spent their life histories exposed to background levels of natural ionizing radiation. To document the role that radiation plays, the deprivation of these natural levels has been studied by incubating organisms in the shielded space of underground laboratories. We report here on two studies (Study I and Study II) using Aedes aegypti for the first time as a model organism incubated 655 meters underground at the Waste Isolation Pilot Plant (WIPP) outside of Carlsbad, New Mexico, U.S.A. Male mosquitos were incubated at the surface exposed to natural background radiation, and were compared to two underground treatments in which incubators were supplemented with radiation sources used to mimic background and these groups were compared to the underground, radiation-deprived treatment. In Study I, the mosquitos incubated underground in the absence of natural radiation had higher levels of mortality compared to those incubated at the surface and PCA plots of the two transcriptomes were clearly differentiated. Study II was conducted the following year and the experiment was narrowed to include only the surface control and underground, radiation-deprived treatment which allowed for four biological replicates. Again, there was a higher level of mortality in the mosquitos grown underground compared mosquitos grown at the surface. Transcriptomes were not as clearly differentiated by PCA analysis and fecundity data were similar between the two groups. Functional analysis of transcriptomic DEGs from two independent studies suggested there are stress responses in radiation deprived mosquitoes. The absence of a secondary stressor in Study II is discussed as an explanation for the transcriptome differences in the two experiments.

Mitochondrial potassium channels play an important role in regulating cellular metabolism, redox balance, and survival, particularly in excitable tissues such as the heart. Among them, the mitochondrial large-conductance calcium-activated potassium (mitoBKCa) channel has been implicated in cardioprotection during ischemia-reperfusion injury. At the same time, growing evidence indicates that mitochondria act as light responsive organelles, with cytochrome c oxidase (COX) serving as a primary chromophore for red and near-infrared (NIR) light. In this study, we investigated whether 820 nm infrared light modulates mitoBKCa channel activity in mitochondria isolated from guinea pig cardiomyocytes. Using patch-clamp recordings of mitoplasts, we demonstrated that illumination at 820 nm NIR wavelength enhanced mitoBKCa channel activity in a redox-dependent manner. Our findings reveal a previously unrecognized mechanism linking NIR light modulation via COX to the regulation of cardiac mitoBKCa channels as a metabolic sensor. This study identifies the mitoBKCa channel as a novel effector of light-induced mitochondrial signaling and suggests that modulation of cardiac mitochondrial potassium transport by NIR light may contribute to cardioprotective effects. These results provide new insight into the integration of bioenergetic and photoregulatory processes in mitochondria and support the development of non-pharmacological strategies targeting mitochondrial function.

PurposeTo characterize corneal surface temperature changes induced by different eye-rubbing techniques in healthy individuals and to investigate the factors influencing temperature change. SettingEskisehir Osmangazi University DesignCross-sectional experimental study MethodsThis study included 93 healthy volunteers aged 19-29 years with no ocular pathology. Participants performed three eye-rubbing techniques-fingertip, knuckle, and fingernail rubbing-while corneal temperatures were recorded with a high-resolution thermal camera (FLIR A8200sc, Teledyne FLIR Systems Inc., Boston MA, USA). Subjects rubbed their eyes for 20 seconds with their dominant hand. Linear mixed-effects models were used to compare corneal temperature before and after eye rubbing and to examine the effect of covariates. ResultsAll eye rubbing techniques significantly increased corneal temperature (fingertip: 1.02 +/-0.58 degrees Celsius, knuckle: 1.03 +/-0.54 degrees Celsius, fingernail: 1.12 +/-0.52 degrees Celsius; all p<0.001), with no significant differences between techniques (p>0.05). Age showed a negative correlation with corneal temperature increase across all rubbing methods (all unadjusted p<0.05), remaining significant only for the fingertip technique after FDR correction (p<0.001). IHA correlated positively with temperature increase for fingertip and knuckle rubbing after FDR adjustment (p= 0.003 and <0.001, respectively). The subgroup analysis indicated that approximately 0.6 degrees Celsius of every 1 degrees Celsius rise in corneal temperature could be attributed to eye closure alone, while the remainder was likely due to mechanical effects of eye rubbing. ConclusionFingertip, knuckle, and fingernail rubbing each produced a transient but significant rise of approximately 1 degree Celsius in corneal temperature. Greater temperature elevation was associated with younger age and higher corneal asymmetry.