Low Light Levels Research Articles

Biotic and abiotic effects on tree regeneration vary by life stage in European primary forests

An observed acceleration of tree mortality rates in European forests has been attributed to the impacts of climate change and extreme disturbances. Ecosystem recovery depends on regeneration success, but the recruitment of juveniles has been recognized as bottleneck in the development of forests. We investigated the potential importance of biotic (canopy tree abundance, ungulate herbivory) and abiotic (light, soil nutrients) factors in the limitation of regeneration in montane primary forests in central Europe. We used widely distributed forest inventory data (n = 348 plots) for two forest types, multiple tree taxa, and two life stages (seedlings and saplings). Seedling densities were promoted by more abundant parent trees, but saplings were either negatively influenced or unaffected by the number of conspecific adults. Browsing intensity (per capita defoliation severity) strongly limited the density of seedlings, but not saplings, at a community level. Low understory light levels were positively associated with seedling densities, but either did not affect or depressed sapling abundance A tolerance of shading was enhanced by nitrogen availability in some taxa. Our findings reflect highly complex, context‐specific regeneration processes that vary by species and life stage within species.

The Range of the Colonial Microcystis’ Biomass for Shift to Diatom Aggregates Under Aeration Mixing and Low Light

In order to investigate non-cyanobacteria dominance succession from Microcystis blooms, particularly to diatom dominance, an experiment using varying colonial Microcystis biomasses expressed as bulk concentrations of 2.0, 4.0, 6.0, 8.0, 10.0, 12.0, 14.0, 16.0, 18.0, 20.0, 22.0, and 24.0 mL L−1 was undertaken under continuous aeration mixing in a greenhouse during a hot summer where shading had reduced light level by 97%. The results showed that the algal shift process was affected by the initial biomass of the colonial Microcystis, and the algal community diversified. When the Microcystis bulk concentration was between 2.0 and 16.0 mL L−1, the bloom became dominated by diatom Nitzschia palea, which aggregated on the mucilage sheathes of the Microcystis colonies. The diatom density at bulk concentration biomass of 2.0 mL L−1 reached a maximum at 2.8 × 105 cells mL−1 on day 27. When the bulk concentration was at 18.0–24.0 mL L−1, no diatom dominance appeared. The shift from a Microcystis bloom to diatom dominance was affected by the initial Microcystis biomass, and the most suitable bulk concentration biomass for colonial Microcystis was at 2–12 mL L−1, in which the chlorophyll-a level was about from 285 to 1714 μg L−1. The mechanism underlying this algal shift may be that the low light and nutrient levels in the Microcystis bloom promoted diatom aggregation growth on the mucilage sheaths of Microcystis colonies under continuous aeration mixing.

Myopia control strategies: A systematic review and meta-meta-analysis.

To summarise pooled estimates of the efficacies of various myopia control interventions, as drawn from published meta-analyses. PubMed, SCOPUS and Web of Science were searched from inception to February 2024 for systematic reviews and meta-analyses reporting treatment effects of various myopia control strategies. The qualities of the included meta-analyses were assessed using the 16-item A MeaSurement Tool to Assess systematic Reviews (AMSTAR) 2. An intervention was defined as having a clinically significant effect if it resulted in a change in spherical equivalent refraction (SER) of ≥0.50 D/year or axial length (AL) change of ≤-0.18 mm/year. A total of 38 studies were identified. The overall respective changes in SER and AL, mean difference (95% CI) were high-concentration (≥0.5%) atropine 0.67 D (0.58-0.77) and -0.24 mm (-0.36 to -0.11); moderate-concentration (>0.05% to <0.5%) atropine 0.48 D (0.34-0.62) and -0.23 mm (-0.27 to -0.19); low-concentration (0.01%, 0.025%, 0.05%) atropine 0.33 D (0.23-0.43) and -0.14 mm (-0.19 to -0.09); orthokeratology -0.47 mm (-0.66 to -0.28); peripheral plus soft contact lenses 0.30 D (0.18-0.42) and -0.35 mm (-0.62 to -0.08); peripheral plus spectacles 0.77 D (0.40-1.14) and -0.43 mm (-0.78 to -0.08); multifocal spectacles 0.21 D (0.11-0.31); repeated low-level red light therapy 0.55 D (0.46-0.65) and -0.25 mm (-0.29 to -0.20); outdoor time 0.17 D (0.16-0.18) and -0.04 mm (-0.06 to -0.01). High and moderate concentrations of atropine, orthokeratology, peripheral plus spectacles and repeated low-level red light demonstrated clinically significant effects on slowing AL elongation, while high and moderate concentrations of atropine, peripheral plus spectacles and repeated low-level red light demonstrated clinically significant effects on slowing SER progression.

Red and Green LED Light Therapy: A Comparative Study in Androgenetic Alopecia.

Androgenetic alopecia (AGA) affects both men and women, characterized by progressive hair thinning. While current treatments like minoxidil and finasteride have efficacy limitations and side effects, low-level light therapy (LLLT) using red or near-infrared light has emerged as a promising alternative. Recent animal studies suggest potential benefits from green LED light, though human data are sparse. This study utilized an innovative LED helmet emitting red and green LED light on respective halves of the frontal scalp, delivering an energy density of 40 J/cm2 over 20 min. Clinical photography, physician evaluations on a 7-point scale, patient satisfaction, and measurements of hair density and hair diameter were employed. Data were analyzed using linear mixed-effects models, with significance set at p < 0.05. Seventeen participants (47.1% male, 52.9% female, average age 46.47 years) demonstrated notable improvements after 6 months of treatment. Red and green LEDs both significantly increased hair diameter, non-vellus hair density, and satisfaction scores. Notably, the red LED therapy resulted in a statistically significant decrease in vellus hair density and achieved a greater increase in hair diameter compared to the green LED therapy. Minimal adverse effects were reported, primarily consisting of tolerable scalp heat and mild redness. Both red and green LED therapies effectively enhanced hair growth, increasing density and thickness over 6 months. Red LED demonstrated superior improvements in specific measures. Consequently, both therapies present safe and viable alternatives for the management of AGA, expanding the repertoire of available treatment options.

Exploring photobiomodulation in the management of bowel diseases: a concise critical review.

The complexity of the gastrointestinal system plays a crucial role in coordinating essential processes such as digestion, nutrient absorption, and waste elimination. inflammatory bowel diseases (IBD) pose significant treatment challenges due to their complex aetiology and varied symptoms. Conventional therapeutic approaches often involve pharmacological interventions, which may have side effects and limited efficacy. Photobiomodulation (PBM), also known as low-level light therapy, has emerged as a promising therapeutic or adjunctive alternative in the treatment of intestinal diseases. The search was conducted in the MEDLINE database via PubMed, SCOPUS, covering the period from 1990 to 2024. A total of 72 studies were selected, of which 9 focused on inflammatory bowel diseases IBD, including ulcerative colitis (UC) and Crohn's disease (CD). Among these studies, 1 was clinical protocol while eight experimental. The results showed that PBM has a significant positive effect in IBD studies in rats, with reduction of intestinal inflammation, improvement of mucosal integrity, and modulation of the immune response. However, no clinical studies were found necessary to obtain results and establish effective and safe treatment protocols. Nevertheless, PBM holds potential as a non-invasive and complementary therapeutic approach for managing IBD, offering new perspectives for the treatment of chronic intestinal diseases. Therefore, this brief review emphasizes the need to transition from preclinical research to clinical research on this topic and highlights the scarcity of clinical studies.

Wearable Light Loggers in Field Conditions: Corneal Light Characteristics, User Compliance, and Acceptance.

Understanding user challenges with light dosimeters is crucial for designing more acceptable devices and advancing light exposure research. We systematically evaluated the usability and acceptability of a light dosimeter (lido) with 29 participants who wore the dosimeter near the corneal plane of the eye for 5 days. Common reasons for not wearing the dosimeter included exercise, recharging, wet environments, public places, and discomfort. Despite these issues, participants adhered to using the dosimeter with high compliance (89% of recording time). Our findings revealed a significant discrepancy between mean (300 lxmEDI) and median (51 lxmEDI) melanopic equivalent daylight illuminance. This discrepancy indicates that the participants were exposed to significantly lower light levels most of the time. Specifically, participants were exposed to light levels above 250 lxmEDI for only 14% of their wearing time. This highlights the need for increased exposure to recommended light levels. In the evening, participants were exposed to less than the recommended 10 lxmEDI for 58% of their wearing time, which is in line with the guidelines for reducing light exposure before sleep. This study highlights the urgent need for strategies to increase daily light exposure that are more in line with circadian health recommendations.

The Effect of Repeated Low-Level Red-Light Therapy on Myopia Control and Choroid.

To investigate the long-term effects of repeated low-level red light (RLRL) therapy on the axial length (AL), spherical equivalent (SE), and choroidal parameters. Two hundred eight myopic eyes were recruited. The RLRL group included 100 eyes, whereas the control group included 108 eyes. Throughout the one-year follow-up period, changes in AL and SE were recorded for both groups. The RLRL group underwent additional choroidal imaging, and changes in choroidal thickness (CT), choroidal vascularity (CV), and choriocapillaris luminal area (CLA) were assessed before and after RLRL therapy. During the follow-up period, the changing trends in AL and SE differed significantly between the RLRL and control groups. In the RLRL group, AL decreased at three and six months (both P < 0.05) and returned to pretreatment values at 12months (P = 0.453). In contrast, AL increased significantly throughout the follow-up period (three, six, and 12months) in the control group (all P < 0.001). The SE increased significantly during the entire follow-up period in the RLRL group (all P < 0.001), whereas it decreased significantly in the control group (all P < 0.05). Regarding choroidal parameters, significant improvements were observed in CT, CV and CLA throughout the follow-up period (all P < 0.05), and changes in most choroidal parameters were significantly correlated with changes in AL and SE during the follow-up period (all P < 0.05). Furthermore, AL, SE, and most choroidal parameters showed significant correlations between changes at three and 12months (all P < 0.05). RLRL therapy significantly improved choroidal blood perfusion and circulation, which may explain the observed slowing or reversal of myopia progression in the RLRL group. Thus RLRL therapy may be a novel and effective method for controlling myopia. Furthermore, the short-term effect of photobiomodulation therapy (i.e., changes at three months) can be used to predict the long-term effects (i.e., changes at 12months). In this study, RLRL therapy showed a significant control effect on the development of axial length and spherical equivalent. RLRL therapy also promoted the choroidal blood perfusion and circulation. RLRL therapy could be a novel and effective method for myopia control.

LLD-GAN: An end-to-end network for low-light image demosaicking

Demosaicking of low and ultra-low light images has wide applications in the fields of consumer electronics, security, and industrial machine vision. Denoising is a challenge in the demosaicking process. This study introduces a comprehensive end-to-end low-light demosaicking framework called LLD-GAN (Low Light Demosaicking Generative Adversarial Network), which greatly reduces the computational complexity. Our architecture employs a Wasserstein GAN framework enhanced by a gradient penalty mechanism. We have redesigned the generator based on the UNet++ network as well as its corresponding discriminator, which makes the model learning more efficient. In addition, we propose a new loss metric grounded in the principles of perceptual loss to obtain images with better visual quality. The contribution of Wasserstein GAN with gradient penalty and perceptual loss function was proved to be beneficial by our ablation experiments. For RGB images, we tested the proposed model under a wide range of low light levels, from 1/30 to 1/150 of normal light level, for 16-bit images with added noise. For actual low-light raw sensor images, the model was evaluated under three distinct lighting conditions: 1/100, 1/250, and 1/300 of normal exposure. The qualitative and quantitative comparison against advanced techniques demonstrates the validity and superiority of the LLD-GAN as a unified denoising-demosaicking tool.

Vision at high latitudes: High sensitivity without specific boreal adaptations in photoreception in reindeer (Rangifer tarandus L.)

Abstract The light climate at high latitudes, in particular the extended twilight of winter and the reduced diel variation in light level in midsummer and midwinter, potentially constrains visual function and the synchronisation of temporal organisation in polar species. In this paper, we describe the temporal pattern and variation in the spectral composition and brightness of skylight (daylight, twilight, moonlight, starlight, airglow and aurorae) at high latitudes and review photoreception of reindeer/caribou (Rangifer tarandus; ‘Rangifer’) which is one of the few polar resident species for which data are available. Experimental data indicate that the rods of Rangifer may be stimulated by levels of ambient light lower than those occurring during astronomical twilight (solar angle &lt;−18°). Several features of the eyes of Rangifer contribute to their visual capability under extended twilight. These include transmission of UV through the optical media, which enables the animals to exploit the shorter wavelengths characteristic of twilight, and a shift in the peak spectral reflectance of the tapetum lucidum (TL) from around 640 nm in summer to around 450 nm in winter, which increases retinal illumination at short wavelengths. Enhanced sensitivity to short wavelengths is likely to enhance the contrast of some objects and hence the ability of Rangifer to discriminate forage plants and to detect other animals (conspecifics or predators) against a snowy background under low illuminance. There is, nevertheless, currently no evidence of any specific boreal adaptation in their visual system: (i) The eyes of Rangifer, and by inference the area of the dilated pupil, are no larger than expected based on the allometry of eye size in ruminants. (ii) There is no evidence of a change in the spectral sensitivity of photoreceptors associated with detection of UVa. (iii) Transmission of UV through the anterior eye is not unique to Rangifer. (iv) The blue shift in the reflectance of the winter TL appears to be a passive response to prolonged dilation of the pupil and there is no a priori reason not to predict the same response in other large ungulates exposed to low light levels. (v) There is no conclusive evidence of a seasonal shift in absolute retinal sensitivity in Rangifer. (vi) Weak circadian organisation in Rangifer has tentatively been linked to mutations within the circadian molecular clockwork but it remains unclear to what extent this represents a specific adaptation to high latitude. Read the free Plain Language Summary for this article on the Journal blog.

Seasonal Rise in the Contents of Microcystin-LR and Odorous Substances Due to Cyanobacterial Blooms in a Drinking Water Reservoir Supplying Xinyang City, China.

Cyanobacterial blooms have become a serious water pollution problem in many parts of the world, and the monitoring and study of the impacts of biotoxins on human health are of vital importance. In this study, the contents of microcystin-LR, 2-methylisoborneol, and geosmin were measured in water and sediment samples from Nanwan Reservoir, China, by means of bimonthly sampling between February and December 2023. The physicochemical and hydrochemical factors and phytoplankton dynamics in the reservoir were also investigated. The results showed that the overall mean concentration of microcystin-LR (0.729 μg/L) in summer approached the guiding standard (1 μg/L) set by the WHO for drinking water. Furthermore, the content of 2-methylisoborneol (143.5 ng/L) was 14 times higher than the national standard (10 ng/L). The results of laboratory cultures showed that lower light levels and medium temperatures were suitable for the growth of Microcystis and Planktothricoides but higher temperatures promoted the synthesis and release of microcystin-LR and 2-methylisoborneol. In addition, the results of co-cultures showed that the growth of Planktothricoides was inhibited by Microcystis. Our results suggest that cyanobacterial bloom and the presence of the metabolites 2-methylisoborneol and microcystin-LR can decrease the drinking water quality of Nanwan Reservoir.

Photochemical Synthesis of Sericin-Coated Gold Nanorods and Their Antibacterial Activity under Low-Level Near-Infrared Light.

Gold nanorods (GNRs) are unique nanoparticles with easily functionalized surfaces, multiple synthesis methods, photothermal conversion, and surface plasmon resonance effects. These properties make GNRs suitable for various biological applications. However, a rapid synthesis of GNRs using less toxic chemicals is needed. The photochemical method is a viable option that can synthesize GNRs quickly while using fewer chemicals. A photochemical method is reported for the synthesis of GNRs using Irgacure-2959 as a reducing agent. This method could be used to synthesize GNRs with a rod-like shape within 30 min. Additionally, GNRs were coated with sericin (GNRs-SC) to further reduce their toxicity in human dermal fibroblast adult cells. Low-level near-infrared (NIR) light was applied to enhance the photothermal therapy of both GNRs and GNRs-SC. The results showed that GNRs and GNRs-SC under low-level NIR light have enhanced antibacterial activity against Staphylococcus aureus and Escherichia coli, as well as antibiofilm activity against S. aureus. Furthermore, GNRs-SC showed good biocompatibility with antibacterial and antibiofilm activities. These results indicate that GNRs-SC are good candidates for various biological applications.

Depth Video-Based Secondary Action Recognition in Vehicles via Convolutional Neural Network and Bidirectional Long Short-Term Memory with Spatial Enhanced Attention Mechanism

Secondary actions in vehicles are activities that drivers engage in while driving that are not directly related to the primary task of operating the vehicle. Secondary Action Recognition (SAR) in drivers is vital for enhancing road safety and minimizing accidents related to distracted driving. It also plays an important part in modern car driving systems such as Advanced Driving Assistance Systems (ADASs), as it helps identify distractions and predict the driver’s intent. Traditional methods of action recognition in vehicles mostly rely on RGB videos, which can be significantly impacted by external conditions such as low light levels. In this research, we introduce a novel method for SAR. Our approach utilizes depth-video data obtained from a depth sensor located in a vehicle. Our methodology leverages the Convolutional Neural Network (CNN), which is enhanced by the Spatial Enhanced Attention Mechanism (SEAM) and combined with Bidirectional Long Short-Term Memory (Bi-LSTM) networks. This method significantly enhances action recognition ability in depth videos by improving both the spatial and temporal aspects. We conduct experiments using K-fold cross validation, and the experimental results show that on the public benchmark dataset Drive&amp;Act, our proposed method shows significant improvement in SAR compared to the state-of-the-art methods, reaching an accuracy of about 84% in SAR in depth videos.

Effect of electron scattering of microchannel plates on the resolution and halo size of UV image intensifier

Abstract Aiming at the problem that the current theoretical model for calculating the resolution of UV(ultraviolet) low-light level image intensifier is not perfect enough to give the optimization conditions directly, the effects of parameters such as the thickness of anti-ion feedback film, MCP(microchannel plate) bevel angle, the depth of the rear electrode and the length-diameter ratio of the channel plate on the photoelectron transport characteristics of UV low-light level image intensifier are analyzed through systematic theoretical research. Experimental results show that optimizing these parameters can significantly improve the performance of the low-light image intensifier. Specifically, when the thickness of the anti-ion feedback film is 4nm, the bevel angle is 8°, the length-diameter ratio is 50, and the back-end electrode is deepened to 10μm, the theoretical image quality of the UV low-light image intensifier reaches a better level. This study has theoretical guidance significance for the development of high-resolution ultraviolet image intensifiers in the field of optoelectronic imaging, and also plays a key role in improving angular resolution in the application of sun blind ultraviolet warning.

Low Intensity Laser Therapy: A Review of Its Applications and Effectiveness in Health, General Dentistry and Endodontics

Aims: To evaluate the use of low-level laser therapy in endodontic treatment and its broader applicability in General Health and Dentistry. Study Design: Literature review. Place and Duration of Study: The study involved searching articles and book chapters in the Google Scholar and PubMed databases from 2018 to 2023, with the review concluding in 2024. Methodology: The review used descriptors from the Brazilian Health Sciences Descriptors database: Laser Therapy, Low-Level Light Therapy, Endodontic Treatment, Dentistry, and their Portuguese equivalents. A total of 34 articles were selected, focusing exclusively on low-level laser therapy and its applications. Articles not addressing this specific therapy were excluded. Results: Low-level laser therapy is frequently used as an adjunct in general health, dentistry and endodontic treatment. Clinical applications, such as postoperative pain control, root canal system disinfection, periapical surgery, and tissue repair, showed promising results. However, more theoretical and clinical evidence is still required to fully establish its efficacy. Further research is needed to strengthen the evidence base and optimize its clinical use. Conclusion: Low-level laser therapy offers a potential non-invasive treatment option in endodontics, with satisfactory outcomes in various clinical applications.

Photobiomodulation Therapy Effects at Different Stages of the Dystrophic Phenotype: A Histomorphometric Study

ObjectiveThe purpose of this study was to evaluate the effects of photobiomodulation therapy (PBMT) on the gastrocnemius muscle of X-linked muscular dystrophy (mdx) mice. MethodsThe study used an experimental model of Duchenne muscular dystrophy, at 3 stages of degeneration/regeneration of muscle fibers: an acute stage (14-28 days old), acute and stabilized stages (14-42 days old), and a stabilized stage (28-42 days old). Photobiomodulation therapy (also known as low-level light therapy) at 0.6 J was applied 3 times per week to the dystrophic gastrocnemius muscle of mdx mice at ages 14 to 28, 14 to 42, and 28 to 42 days. After the treatment period, the gastrocnemius muscle was collected, and cryosections were prepared for histopathologic analysis. ResultsIn all 3 stages evaluated, a significant reduction was observed in immunoglobulin G uptake by muscle fibers, the inflammatory area, macrophage infiltration, the reactive dihydroethidium area, and the number of autofluorescent lipofuscin granules in the gastrocnemius muscle of mdx mice after PBMT. ConclusionThe results demonstrated that low-level light therapy, when applied during or after the acute phase of the degeneration/regeneration muscle process, improves the pathological histomorphologic features in dystrophic muscle. Based on these results, PBMT appears to be a promising therapy for dystrophinopathies, warranting further research in humans to verify its efficacy.

Untangling poikilohydry and desiccation tolerance: evolutionary and macroecological drivers in ferns.

Poikilohydry describes the inability of plants to internally regulate their water content (hydroregulation), whereas desiccation tolerance (DT) refers to plants ability to restore normal metabolic functions upon rehydration. The failure to clearly separate these two adaptations has impeded a comprehensive understanding of their unique evolutionary and ecological drivers. Unlike bryophytes and angiosperms, these adaptations in ferns are sometimes uncorrelated, offering a unique opportunity to navigate their intricate interplay. We classified ferns into two syndromes: the Hymenophyllum-type (H-type), encompassing species with filmy leaves lacking stomata that experience extreme poikilohydry and varying degrees of DT, and the Pleopeltis-type (P-type), consisting of resurrection plants with variable hydroregulation but high DT. The H-type evolved during globally cool Icehouse periods, as an adaptation to low light levels in damp, shady habitats, and currently prevails in wet environments. Conversely, the P-type evolved predominantly under Greenhouse periods as an adaptation to periodic water shortage, with most extant species thriving in warm, seasonally dry habitats. Out study underscores the fundamental differences between poikilohydry and DT, emphasizing the imperative to meticulously differentiate and qualify the strength of each strategy as well as their interactions, as a basis for understanding the genetic and evolutionary background of these ecologically crucial adaptations.

The efficacy of light-guiding microneedle patch for stimulating hair growth in androgenetic alopecia.

Androgenetic alopecia (AGA) is the most common form of hair loss characterized by miniaturization of hair follicles. Low-level light therapy (LLLT) and microneedling have shown potential in promoting hair regrowth. This study aims to evaluate the efficacy of an innovative light-emitting diode (LED) helmet cooperated with a novel light-guiding microneedle patch (LMNP) for stimulating hair growth in AGA. In this randomized clinical trial, 16 AGA patients received treatments using light-guiding microneedle patches (LMNPs) illuminated by a LED helmet equipped with green (522nm) and red (633nm) LEDs, delivering 50mW/cm2 power and 40J/cm2 energy. Treatments were applied weekly for 24weeks, targeting the frontal recession area. The right side of the scalp was treated with green light and the left with red light, each combined with a LMNP featuring 900µm height needles at a density of 105 per square centimeter. Hair density and diameter, along with patient and physician satisfaction scores, were assessed monthly. Both red and green LED treatments with LMNP, significantly enhanced hair density and diameter. Satisfaction scores, as reported by both physicians and participants, increased over time. Comparative analyses revealed no statistically significant differences in average satisfaction scores or in changes in hair density and diameter between the groups by the end of the study. Additionally, no serious adverse effects were reported, highlighting the safety of the treatments. The combined Light sources which is portable LED helmet and LMNPs shows promise as a non-invasive, effective treatment for AGA, with similar efficacy between red and green wavelengths.

Light pollution: time to consider testicular effects.

Technological advances have led to a modern-day lighting and smartphone revolution, with artificial light exposure at night increasing to levels never before seen in the evolutionary history of living systems on Earth. Light as a pollutant, however, remains largely unrecognized, and the reproductive effects of light pollution are mostly if not entirely unconsidered. This is despite the reproductive system being intricately linked to metabolism and the circadian system, both of which can be disturbed even by low levels of light. Here, we aim to change this perspective by reviewing the physiological and pathophysiological mechanisms by which light exposure alters the intricate hormonal, metabolic and reproductive networks that are relevant to reproductive toxicology. Nascent human studies have recently identified the photoreceptors responsible for the light dose relationship with melatonin suppression and circadian re-entrainment, directly shown the association between the alignment of light-dark cycles with activity-rest cycles on metabolic health and provided proof-of-principle that properly timed blue light-enriched and blue light-depleted delivery can accelerate circadian re-entrainment. With these advances, there is now a need to consider testicular effects of light pollution.

The cytotoxic effect of 4 different wavelengths of Low-level laser therapy on squamous cell carcinoma – An invitro study

Background: Low-level laser therapy is a noninvasive method with the potential ability to change the balance of cell mediators and gene expressions. It affects cellular function resulting in beneficial clinical effects. This study aims to assess the effect of low-level light therapy (LLLT) using four different laser wavelengths on oral carcinoma cell viability in vitro. Methods and Material: HN5 human head and neck squamous cell carcinoma cell lines (HNSCC) were cultured and irradiated using four wavelengths of blue (485 nm), green (532nm), red (660 nm), and near Infra-red (810 nm) in a continuous mode with a dose of 1 J/cm2 (0.1W, 10sec) every 24hours for five consecutive days. Cell viability was assessed by evaluating mitochondrial activity by MTT assay. Results: All the wavelengths resulted in reduced viability of these cells compared to the controls. (P&lt;0.05) There were statistically significant differences in cell viability between different wavelengths (P&lt;0.001). The 810 nm laser irradiation showed the highest percentage of cell survival (55.92%) while 660 nm induced the lowest (36.02%). Conclusion: Different laser wavelengths may result in different effects on irradiated cells and red irradiation showed the lowest cell viability and the infrared laser had the highest cell viability results.

Safety, Tolerability, and Short-Term Efficacy of Low-Level Light Therapy for Dry Age-Related Macular Degeneration.

Photobiomodulation (PBM) has become a promising approach for slowing the progression of early and intermediate dry age-related macular degeneration (dAMD) to advanced AMD. This technique uses light to penetrate tissues and activate molecules that influence biochemical reactions and cellular metabolism. This preliminary analysis is aimed at assessing the safety, tolerability, and short-term effectiveness of the EYE-LIGHT®PBM treatment device in patients with dAMD. The EYE-LIGHT® device employs two wavelengths, 590nm (yellow) and 630nm (red), in both continuous and pulsed modes. Patients over 50years of age with a diagnosis of dAMD in any AREDS (Age-Related Eye Disease Study) category were randomly assigned to either the treatment group or the sham group. The treatment plan consisted of an initial cycle of two sessions per week for 4weeks. Safety, tolerability, and compliance outcomes, along with functional and anatomical outcomes, were assessed at the end of the fourth month. This preliminary analysis included data from 76 patients (152 eyes). All patients were fully compliant with treatment sessions, and only one fifth of patients treated with PBM reported mild ocular adverse events, highlighting exceptional results in terms of tolerability and adherence. Changes in best-corrected visual acuity (BCVA) from baseline to month 4 differed significantly between the sham and PBM-treated groups, favoring the latter, with a higher proportion achieving a gain of five or more letters post-treatment (8.9% vs. 20.3%, respectively; p = 0.043). No significant differences in central subfield thickness (CST) were observed between the two groups over the 4-month period. The study also found a statistically significant disparity in mean drusen volume changes from baseline to month 4 between the groups in favor of patients treated with PBM (p = 0.013). These preliminary results indicate that PBM treatment using the EYE-LIGHT® system is safe and well tolerated among patients with dAMD. Furthermore, both functional and anatomical data support the treatment's short-term efficacy. ClinicalTrials.gov identifier NCT06046118.