Promoting adolescent sleep and circadian function: A narrative review on the importance of daylight access in schools

Adolescent sleep disturbances and circadian delays pose significant challenges to mood and daytime functioning. In this narrative review, we explore the impact of light on sleep and highlight the importance of monitoring and managing light exposure in adolescents throughout the day and night. The benefits of daylight exposure in mitigating sleep and circadian disruptions are well-established; however, interventions targeting access to daylight in adolescents remain understudied and underutilized. The primary aim of this narrative review is to bring attention to this gap in the literature and propose the need for institutional-level interventions that promote access to daylight, especially considering adolescents' early school start times and substantial time spent indoors on weekdays. School-led interventions, such as active commuting to school and outdoor curriculums, have promising effects on sleep and circadian rhythms. Additionally, practical measures to optimize natural light in classrooms, including managing blinds and designing conducive environments, should also be considered. While future studies are necessary to facilitate the implementation of interventions, the potential for these school-level interventions to support adolescent sleep health is evident. Aiming for integration of individual-level regulation and institutional-level intervention of light exposure is necessary for optimal outcomes.

Light Distribution in 3D-Printed Thermoplastics

Daylight distribution is an essential performance parameter for building facades that aim to maximize user comfort while maintaining energy efficiency. This study investigates the feasibility of using 3D-printed thermoplastic to improve daylight distribution and transmission. To identify how geometry influences light distribution and transmission, 12 samples with various patterns were robotically fabricated. In a physical simulation of spring, summer, and winter, a robotic arm was used to direct light onto the samples in both the vertical and horizontal print pattern directions. In addition, three samples of conventional facade materials, including a polycarbonate panel, a polycarbonate sheet, and a single sheet of glass, were compared with the 3D-printed samples. All samples were examined and compared using high dynamic range imaging to qualitatively characterize luminance. The data analysis demonstrated that 3D-printed geometry can successfully generate customizable diffusive light distribution based on the needs of the user. Furthermore, the results showed that the vertical pattern direction had higher light transmission values than the horizontal pattern direction.

Review of the European Society for Photodynamic Therapy (Euro-PDT) Annual Congress 2022

This article reviews the 2022 European Society for Photodynamic Therapy (Euro-PDT) Annual Congress. PDT has been investigated for the treatment of a broad number of oncologic, infectious and inflammatory indications. New studies confirm the potential for wider use of topical PDT for acne and photoaging, as well as several uncommon conditions including tinea capitis, Mycobacterium marinum, cutaneous alternariosis, resistant acral warts, eyelid Bowen's disease, mycosis fungoides, pseudolymphoma, and graft-versus-host disease. Hidradenitis suppurativa patients may also benefit from intra-lesional PDT. Several methods of delivering PDT have been validated, including conventional, daylight and artificial daylight PDT. Light-emitting fabrics have emerged as an innovative solution to the delivery of uniform light over the scalp as well as anatomically-challenging sites, with opportunities now to control and monitor these devices via mobile phone applications. Pre-treatment of patients with thicker, more difficult-to-treat actinic keratoses (AK) with calcitriol appears to be a practical approach to increasing efficacy, although this is associated with increased local skin reactions. Sequential treatment of AK and photoaging with daylight-PDT and injectable NASHA gel indicates that these two therapeutic approaches offer complementary effects. Potential biomarkers may help predict responsiveness of patients with field cancerization and AK receiving daylight PDT. Over-expression of the proto-oncogene, Myc, has been observed in poor responders, whilst the tumour suppressor gene, PTEN, showed under-expression. The potential for use and methods of delivery of topical PDT for dermatological indications continue to expand the enhanced choice of treatment offered to patients.

Time Spent Outdoors and Associations with Sleep, Optimism, Happiness and Health before and during the COVID-19 Pandemic in Austria

Social restriction measures (SRM) implemented during the COVID-19 pandemic led to a reduction in time spent outdoors (TSO). The aim of this study was to describe TSO and evaluate its association with sleep outcomes, optimism, happiness and health-status before and during SRM. Two online surveys were conducted in 2017 (N = 1004) and 2020, during SRM (N = 1010), in samples representative of the age, sex and region of the Austrian population. Information on the duration of TSO, sleep, optimism, happiness and health-status was collected. Multivariable-adjusted logistic regression models were used to study the association of TSO with chronic insomnia, short sleep, late chronotype, optimism, happiness and self-rated health-status. The mean TSO was 3.6 h (SD: 2.18) in 2017 and 2.6 h (SD: 1.87) during times of SRM. Men and participants who were older, married or in a partnership and lived in a rural area reported longer TSO. Participants who spent less time outdoors were more likely to report short sleep or a late chronotype in both surveys and, in 2020, also chronic insomnia. Less TSO was associated with lower happiness and optimism levels and poor health-status. Our findings suggest that TSO may be a protective factor for sleep, mood and health, particularly during stressful and uncertain times.

Evidence-Based Design in the Hospital Environment: A Staff's Burnout Study in the COVID-19 Era

OBJECTIVE

This study aimed to evaluate the evidence-based design of the hospital physical space effect on the burnout of nurses and physicians during COVID-19. The research question was to identify the connection between daylight, nature-view windows, and hospital staff burnout during Covid-19.

BACKGROUND

The evidence-based design in the hospital environment affects the health of the medical staff. The promotion of the hospital environment has a significant effect on healthcare system improvement.

METHODS

This cross-sectional study was performed on 406 nurses and physician's burnout in Guilan province in 2020. Three questionnaires were used: demographic, physical space of the hospital, daylight, nature-view windows, and Maslach Burnout Inventory. Logistic regression (LR) analysis was used to determine the association between burnout and the hospital environment. The significance level was considered with p < .05.

RESULTS

The results showed statistically significant correlations between patient units and the environmental characteristics of the hospitals with staff's burnout (p < .001). Of note, 62.9% of physicians and 71.9% of nurses had moderate work-related burnout. The highest burnout score was seen among staffs of emergency departments adjusted multivariate LR model revealed that 27.1% of work-related burnout in nurses and physicians was predictable with age, light, marital status, and hospitals. Our results showed that accessing more daylight could reduce burnout (p = .018, odds ratio [OR] = 0.910).

CONCLUSION

Based on the result, the daylight impact on burnout reduction is more significant than other factors. It is suggested that adequate lighting, proper environmental design, and nature-view windows could create appropriate space for enhancing medical staff satisfaction and reducing burnout.

Genome-wide gene by environment study of time spent in daylight and chronotype identifies emerging genetic architecture underlying light sensitivity

STUDY OBJECTIVES

Light is the primary stimulus for synchronizing the circadian clock in humans. There are very large interindividual differences in the sensitivity of the circadian clock to light. Little is currently known about the genetic basis for these interindividual differences.

METHODS

We performed a genome-wide gene-by-environment interaction study (GWIS) in 280 897 individuals from the UK Biobank cohort to identify genetic variants that moderate the effect of daytime light exposure on chronotype (individual time of day preference), acting as "light sensitivity" variants for the impact of daylight on the circadian system.

RESULTS

We identified a genome-wide significant SNP mapped to the ARL14EP gene (rs3847634; p < 5 × 10-8), where additional minor alleles were found to enhance the morningness effect of daytime light exposure (βGxE = -.03, SE = 0.005) and were associated with increased gene ARL14EP expression in brain and retinal tissues. Gene-property analysis showed light sensitivity loci were enriched for genes in the G protein-coupled glutamate receptor signaling pathway and genes expressed in Per2+ hypothalamic neurons. Linkage disequilibrium score regression identified Bonferroni significant genetic correlations of greater light sensitivity GWIS with later chronotype and shorter sleep duration. Greater light sensitivity was nominally genetically correlated with insomnia symptoms and risk for post-traumatic stress disorder (PTSD).

CONCLUSIONS

This study is the first to assess light as an important exposure in the genomics of chronotype and is a critical first step in uncovering the genetic architecture of human circadian light sensitivity and its links to sleep and mental health.

Pharmacological Agents Used in the Prevention and Treatment of Actinic Keratosis: A Review

Actinic keratosis (AK) is among the most commonly diagnosed skin diseases with potentially life-threatening repercussions if left untreated. Usage of pharmacologic agents represents one of many therapeutic strategies that can be used to help manage these lesions. Ongoing research into these compounds continues to change our clinical understanding as to which agents most benefit particular patient populations. Indeed, factors such as past personal medical history, lesion location and tolerability of therapy only represent a few considerations that clinicians must account for when prescribing appropriate treatment. This review focuses on specific drugs used in either the prevention or treatment of AKs. Nicotinamide, acitretin and topical 5-fluorouracil (5-FU) continue to be used with fidelity in the chemoprevention of actinic keratosis, although some uncertainty persists in regard to which agents should be used in immunocompetent vs. immunodeficient/immunosuppressed patients. Topical 5-FU, including combination formulations with either calcipotriol or salicylic acid, as well as imiquimod, diclofenac and photodynamic light therapy are all accepted treatment strategies employed to target and eliminate AKs. Five percent of 5-FU is regarded as the most effective therapy in the condition, although the literature has conflictingly shown that lower concentrations of the drug might also be as effective. Topical diclofenac (3%) appears to be less efficacious than 5% 5-FU, 3.75-5% imiquimod and photodynamic light therapy despite its favorable side effect profile. Finally, traditional photodynamic light therapy, while painful, appears to be of higher efficacy in comparison to its more tolerable counterpart, daylight phototherapy.

Effects of bright light therapy on neuroinflammatory and neuroplasticity markers in a diurnal rodent model of Seasonal Affective Disorder

BACKGROUND

Bright light therapy (BLT) is widely used for treating Seasonal Affective Disorder (SAD). However, the neural mechanisms underlying the therapeutic effects of BLT remain largely unexplored. The present study used a diurnal rodent (Nile grass rats; Arvicanthis niloticus) to test the hypothesis that the therapeutic effects of BLT could be, in part, due to reduced neuroinflammation and/or enhanced neuroplasticity. Our previous research has demonstrated that compared to grass rats housed in a summer-like daytime bright light condition (1000 lux), those housed in a winter-like daytime dim light condition (50 lux) showed increased depression- and anxiety-like behaviours, as well as impaired sociosexual behaviours and spatial memory, similar to what is observed in patients suffering from SAD.

MATERIALS AND METHODS

In the present study, male and female grass rats were housed under the winter-like dim daytime light condition (lights on 600-1800 hr, 50 lux). The experimental groups received daily 1-h early morning BLT from 0600-0700 using full-spectrum light (10,000 lux), while the control groups received narrowband red light (λmax, 780 nm). Following 4 weeks of treatment, the expression of several neuroinflammatory or plasticity markers was examined in the medial prefrontal cortex (mPFC), basolateral amygdala (BLA), and the CA1 of the dorsal hippocampus.

RESULTS

For the neuroinflammatory markers, BLT reduced TNF-α in the BLA of females, and upregulated CD11b in the mPFC and IL6 in the BLA in males. For the neuroplasticity markers, BLT downregulated BDNF in the CA1 and TrkB in all three brain regions in females but upregulated BDNF in the BLA and CA1 in males.

CONCLUSIONS

These results indicate that the therapeutic effects of BLT on sleep, mood, and cognition may be attributed in part to mechanisms involving neuroinflammation and neuroplasticity in corticolimbic brain regions. Moreover, these effects appear to vary between sexes.

Smart Dimmable LED Lighting Systems

This paper proposes energy-efficient solutions for the smart light-emitting diode (LED) lighting system, which provides minimal energy consumption while simultaneously satisfying illuminance requirements of the users in a typical office space. In addition to artificial light from dimmable LED lamps, natural daylight coming from external sources, such as windows, is considered as a source of illumination in an indoor environment. In order to reduce total energy consumption, the smart LED system has the possibility to dim LED lamps, resulting in reduced LED output power. Additionally, various LED lamps' functionality, such as semi-angle of the half illuminance and LED tilting, are introduced as an additional parameter to be optimized to achieve greater energy saving of the designed system. In order to properly exploit external lighting, the idea to reduce overall daylight intensity at a users' location is realized by the option to dim the windows with a shading factor. Based on the users' requirements for a minimal and desired level of illumination, the proposed optimization problems can be solved by implementing different optimization algorithms. The obtained solutions are able to give instructions to a smart LED system to manage and control system parameters (LEDs dimming levels, semi-angles of the half illuminance, orientation of LEDs, the shading factor) in order to design total illumination, which ensures minimal energy consumption and users' satisfaction related to illuminance requirements.

Fully home-based methyl aminolevulinate daylight photodynamic therapy for actinic keratosis of the face or scalp: A real life open study

Methyl aminolevulinate daylight photodynamic therapy (MAL DL-PDT) is highly efficacious for the treatment of nonhyperkeratotic actinic keratosis (AK), even when partially performed at home. To evaluate the long-term effectiveness, safety, and patient-reported outcomes of MAL DL-PDT performed completely by the patient in real life conditions. An open prospective study was conducted in Spain among patients diagnosed with at least five AK lesions on the face or the scalp. Patients received instruction and information in infographic format to perform MAL DL-PDT at home. All had been treated with 30% urea daily for 7 days before the day of MAL DL-PDT. Meteorological conditions on the day of the treatment and adverse effects were recorded. Patients underwent follow-up, and a second session of home-based MAL DL-PDT if deemed necessary, 3, 6, and 12 months after the initial treatment session. The study population consisted of 22 patients (19 men and three women, mean [standard deviation, SD] age, 72.05 [6.96] years). A complete response was observed in 47.7% of AK lesions at 3 months (p < 0.001) and 65.9% (n = 199) at 12 months (p < 0.001). Olsen grade II lesions showed the highest rate of response (76.07% at 12 months). The mean (SD) actinic keratosis area and severity index score decreased significantly from 4.99 (2.43) at baseline to 2.33 (1.01) at 12 months (p = 0.0234). Adverse effects were mild and expected. A majority of patients were "satisfied" or "very satisfied" with the treatment instruction provided (90.9%) and the treatment outcome (72.7%). MAL DL-PDT can be applied at home like any other topical treatment for AK. Our results indicate good long-term effectiveness, a high level of patient satisfaction, and no significant side effects.

Shedding light on the pedestrian safety crisis: An analysis across the injury severity spectrum by lighting condition

OBJECTIVE

Pedestrian fatalities in the United States increased 51% from 2009 to 2019. During that time, pedestrian fatalities occurring at night increased by 63.7%, compared to a 17.6% increase for pedestrian fatalities occurring during daylight conditions. Have there also been increases in serious, minor, and possible pedestrian injuries (i.e., have all pedestrian collisions been occurring more frequently)? Have pedestrian collisions been getting more severe (i.e., are there now higher proportions of more severe injuries)? Have trends differed between night and day? What role does street lighting play in the nighttime trends?

METHODS

We analyzed pedestrian fatalities, serious injuries, minor injuries, and possible injuries that occurred in California, North Carolina, and Texas from 2010 to 2019 using linear regressions to explore the strength and statistical significance of trends. We then parsed these trends by lighting condition, exploring outcomes during the day and night and with and without street lighting.

RESULTS

Findings suggest that increases in daytime minor (7.9%) and possible (7.5%) injuries closely mirrored increases in population (9.8%). Increases in daytime fatal/serious injuries were significantly higher (43.1% and 35.1%, respectively), suggesting worsening severities during the day. Increases in nighttime minor/possible injuries (31.9% and 27.6%, respectively) were significantly larger than those during the day, suggesting that pedestrian collisions are occurring more frequently at night. Substantial increases in nighttime fatal/serious injuries (78.0% and 74.7%, respectively) likely reflect a combination of worsening severity (seen throughout the day) and increasing frequency (seen particularly at night). A pedestrian injured in the dark was found to be 5.0 times more likely to be killed than a pedestrian injured during the day. While a lack of street lighting does not seem to be the cause of the disproportionate increase in pedestrian injuries at night, pedestrians struck without a street light were 2.4 times more likely to be killed than those struck in the presence of a street light.

CONCLUSIONS

As we find ourselves in the midst of a pedestrian safety crisis, understanding that severities have increased throughout the entire day and frequencies have increased particularly at night helps illuminate a path forward.

From dawn to dusk-mimicking natural daylight exposure improves circadian rhythm entrainment in patients with severe brain injury

STUDY OBJECTIVES

While light therapy has proven effective in re-entraining circadian rhythms, the potential of such an intervention has not been evaluated systematically in post-comatose patients with disorders of consciousness (DOC), who often have strongly altered circadian rhythms.

METHODS

We recorded skin temperature over 7-8 days in patients with DOC in each of two conditions: habitual light (HL), and dynamic daylight (DDL) condition. While patients were in a room with usual clinic lighting in the HL condition, they were in an otherwise comparable room with biodynamic lighting (i.e. higher illuminance and dynamic changes in spectral characteristics during the day) in the DDL condition. To detect rhythmicity in the patients' temperature data, we computed Lomb-Scargle periodograms and analyzed normalized power, and peak period. Furthermore, we computed interdaily stability and intradaily variability, which provide information about rhythm entrainment and fragmentation.

RESULTS

We analyzed data from 17 patients with DOC (i.e. unresponsive wakefulness syndrome [n = 15] and minimally conscious state [n = 2]). The period length of the patients' temperature rhythms was closer to 24 h in the DDL as compared to the HL condition (median median deviation from 24 h: DDL = 0.52 h, HL = 3.62 h). Specifically, in 11/17 (65%) patients the period length was closer to 24 h in the DDL condition. Furthermore, the patients' rhythm was more pronounced, more stable, and less variable in the DDL condition.

CONCLUSIONS

Our results indicate that DDL stimulation entrains and stabilizes circadian rhythms. This highlights the importance of adequate room lighting as an adjunct therapeutic approach for improving circadian rhythms in severely brain-injured patients.

TRIAL REGISTRATION INFORMATION

German Clinical Trials Register (DRKS00016041); registration: 18.01.2019; recording start: 04.06.2019 https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00016041.

Photodynamic Therapy with 5-Aminolevulinic Acid Patch for the Treatment of Actinic Keratosis

Photodynamic therapy (PDT) using 5-aminolevulinic acid (5-ALA) is an emerging treatment option in the care of actinic keratosis (AK). A self-adhesive 5-ALA patch was recently developed that allows a precise PDT procedure. Here, we review the current literature and report the findings of our case series that observed the outcomes and safety of 5-ALA patch PDT. Ten patients with a total of 40 AKs were treated with a single session of conventional or daylight PDT using 5-ALA patch at the Department of Dermatology and Venereology, Sapienza University of Rome or at the European Institute of Oncology, Milan, Italy. Complete response was observed in three patients, while partial response was seen in seven patients. Overall tolerability was good or excellent, with local adverse events observed in four patients. This is the first case series reported where the 5-ALA patch was applied using daylight PDT, and its efficacy and tolerability in the treatment of AK were demonstrated. In conclusion, the self-adhesive 5-ALA patch is a convenient application of PDT that provides a well-tolerated and effective treatment option with satisfactory cosmetic outcomes.

Daylight-PDT: everything under the sun

5-Aminolevulinic acid-based photodynamic therapy (ALA-PDT) was first implemented over three decades ago and has since been mainly part of clinical practice for the management of pre-cancerous and cancerous skin lesions. Photodynamic therapy relies on the combination of a photosensitizer, light and oxygen to cause photo-oxidative damage of cellular components. 5-Aminolevulinic acid (ALA) is a natural precursor of the heme biosynthetic pathway, which when exogenously administered leads to the accumulation of the photoactivatable protoporphyrin IX. Although, effective and providing excellent cosmetic outcomes, its use has been restricted by the burning, stinging, and prickling sensation associated with treatment, as well as cutaneous adverse reactions that may be induced. Despite intense research in the realm of drug delivery, pain moderation, and light delivery, a novel protocol design using sunlight has led to some of the best results in terms of treatment response and patient satisfaction. Daylight PDT is the protocol of choice for the management of treatment of multiple or confluent actinic keratoses (AK) skin lesions. This review aims to revisit the photophysical, physicochemical and biological characteristics of ALA-PDT, and the underlying mechanisms resulting in daylight PDT efficiency and limitations.

Current Insights into Optimal Lighting for Promoting Sleep and Circadian Health: Brighter Days and the Importance of Sunlight in the Built Environment

This perspective considers the possibility that daytime's intrusion into night made possible by electric lighting may not be as pernicious to sleep and circadian health as the encroachment of nighttime into day wrought by 20th century architectural practices that have left many people estranged from sunlight.

The Association of Self-Reported Iron and Vitamin D Levels on Sleep Quality and Pain Perception in a Subset of Saudi Population

Background and Aims

There has been a rising concern regarding the relationship of iron levels, vitamin D, and consumption of multivitamins on pain perception and sleep quality. The purpose of this study is to shed light on these connections in hopes of enhancing quality of sleep.

Methods

A cross-sectional analysis was used, and data collection was based on close-ended online questionnaire created on Survey Monkey. The survey included an operator designed questionnaire, questions from both the Brief Pain Inventory and Sleep Quality questionnaires. The targeted population was participants who were medically fit, non-pregnant Saudi citizens aged between 25 and 55 years.

Results

Prior to the COVID-19 crisis, data were collected during the months of February and March 2020, with a grand total of 3127 participants, out of which 2774 responses were included. The outcome of the research revealed that diminished levels of vitamin D, and iron had a negative impact on sleep quality. In turn, poor sleep quality had a significant pain response.

Conclusion

This study reveals the detrimental role of vitamins on sleep, and their concurrent domino effect on pain.

Can Annual Daylight Cycles and Seasons Have an Effect on Male Sexual Functions?

Introduction Mammals' sexual functions exhibit seasonal variations that have been attributed to changes in the daylight. In this study, taking into consideration endocrine and psychogenic status, we aimed to investigate whether human males experience changes in erectile functions and sexual desire depending on daylight periods and seasons, and whether periodicity exists in human sexual behavior. Materials and methods International Index of Erectile Function (IIEF) and psychiatric scale scores of 221 male patients were evaluated. In addition, hormonal parameters of the patients were examined. These data were first evaluated in two groups (summer and winter) according to local daylight amounts the participants received. Then IIEF scores were also analyzed according to four conventional seasons (winter, spring, summer, and autumn). Results There was no significant difference in laboratory data, psychiatric scale scores and IIEF evaluations between summer and winter groups. Moreover, no significant difference was found in terms of sexual desire and erectile functions in terms of four seasons (p > 0.05). Conclusion According to the results of this study, there is no periodicity in human sexual functions both in relation to daylight and four seasons.

Access to Daylight at Home Improves Circadian Alignment, Sleep, and Mental Health in Healthy Adults: A Crossover Study

As the primary environmental cue for the body’s master biological clock, light–dark patterns are key for circadian alignment and are ultimately fundamental to multiple dimensions of health including sleep and mental health. Although daylight provides the proper qualities of light for promoting circadian alignment, our modern indoor lifestyles offer fewer opportunities for adequate daylight exposure. This field study explores how increasing circadian-effective light in residences affects circadian phase, sleep, vitality, and mental health. In this crossover study, 20 residents spent one week in their apartments with electrochromic glass windows and another week with functionally standard windows with blinds. Calibrated light sensors revealed higher daytime circadian-effective light levels with the electrochromic glass windows, and participants exhibited consistent melatonin onset, a 22-min earlier sleep onset, and higher sleep regularity. In the blinds condition, participants exhibited a 15-min delay in dim light melatonin onset, a delay in subjective vitality throughout the day, and an overall lower positive affect. This study demonstrates the impact of daytime lighting on the physiological, behavioral, and subjective measures of circadian health in a real-world environment and stresses the importance of designing buildings that optimize daylight for human health and wellbeing.

A split-face clinical trial of conventional red-light photodynamic therapy versus daylight photodynamic therapy for acne vulgaris

BACKGROUND

Photodynamic therapy (PDT) is considered an effective treatment for acne vulgaris. A significant drawback is pain during illumination. Daylight PDT (DL-PDT) is more tolerable.

OBJECTIVE

To assess and compare the efficacy and tolerability of DL-PDT and C-PDT for acne vulgaris through a prospective split-face trial.

METHODS AND MATERIALS

Fifteen patients underwent 4 treatment sessions at 3-week intervals. First, 5-aminolevulinic acid (ALA) was applied to the entire face, after which the face was divided into 2 symmetrical areas: The right side was exposed to sunlight, and the left half was illuminated with red light. Photographs were obtained and evaluated by two dermatologists blinded to the study protocol. The patients reported side effects and downtime.

RESULTS

There was a statistically significant decrease in the number and percent change of inflammatory and non-inflammatory lesions on both sides. Adverse effects were markedly decreased on the DL-PDT side compared to the C-PDT side (p < .01). The average downtime duration was longer for the C-PDT side (p < .001).

CONCLUSION

DL-PDT was at least as effective as C-PDT with fewer adverse effects and a shorter downtime duration.

Temperature-Color Interaction: Subjective Indoor Environmental Perception and Physiological Responses in Virtual Reality

OBJECTIVE

Temperature-color interaction effects on subjective perception and physiological responses are investigated using a novel hybrid experimental method combining thermal and visual stimuli from real and virtual reality (VR) environments, respectively.

BACKGROUND

Despite potential building design applications, studies combining temperature with daylight transmitted through colored glazing are limited due to hard-to-control light conditions. VR is identified as a promising experimental tool for such investigations that overcomes the limitations of experiments using daylight.

METHOD

Fifty-seven people participated in an experiment combining three colored glazing (orange/blue/neutral) and two temperatures (24°C/29°C). Exposed to one color-temperature combination, participants evaluated their thermal, visual, and overall perception, whereas their physiological responses (heart rate, skin conductance, and skin temperature) were continuously measured.

RESULTS

Daylight color significantly affected thermal perception, whereas no significant effects of temperature on visual perception were found. Acceptability of the workspace was affected by both color and temperature. Cross-modal effects from either daylight color or temperature levels on physiological responses were not observed.

CONCLUSION

In the VR setting, the orange daylight led to warmer thermal perception in (close-to-) comfortable temperatures, resulting in a color-induced thermal perception and indicating that orange glazing should be used with caution in a slightly warm environment.

APPLICATION

Findings can be applied to the design of buildings using new glazing technologies with saturated colors, such as transparent photovoltaics. Despite some limitations, the hybrid environment is suggested as a promising experimental tool for future studies on indoor factor interactions.

Shedding light on light exposure in elderly with intellectual disabilities

BACKGROUND

Light exposure affects mood and sleep regulation. Sleep problems and mood complaints are common in elderly with intellectual disabilities (ID) living in care facilities. Insufficient light exposure is hypothesised to contribute to the high prevalence of these problems. The current study is the first to describe the personal light exposure pattern during the waking day in elderly with ID.

METHODS

The study sample consists of 82 elderly with ID (aged 62.3 ± 9.4 years) living in 16 residential homes of three care organisations in the Netherlands. Personal light exposure was measured continuously for 7-10 days using a HOBO data logger light sensor, measuring illuminance at chest height. Participants wore a wrist-worn accelerometer (Actiwatch or Geneactiv) to indicate the bedtimes to determine the waking day.

RESULTS

The variation in illuminance is small during the waking day. Elderly with ID spend most of their waking day (mean duration = 14:32:43 h) in dim light (1-500 lux) environment and spend a median of 32 min in light > 1000 lux. Within participants, the threshold associated with better sleep (>50 min of light > 1000 lux) was reached for 34% of the days, and the threshold associated with less depressive symptoms (>30 min of light > 1000 lux) was reached in 46% of the days. Exposure > 1000 lux was lower during weekends than during weekdays.

CONCLUSION

Elderly with ID spend most of their waking day in low light levels and did not meet the proposed values associated with better sleep and mood. Given the importance of adequate light exposure for regulation of sleep and mood, and the prevalence of sleep and mood problems in elderly with ID, the current study suggests that the lit environment for this already frail population should be given more attention.

Review of the European Society for Photodynamic Therapy (Euro-PDT) Annual Congress 2020

This article reviews the 2020 European Society for Photodynamic Therapy (Euro-PDT) Annual Congress. Cutting edge studies included assessment of immunohistochemical variables influencing response of basal cell carcinomas and Bowen's disease to PDT with p53, the only biomarker associated with good response in both conditions. A further study indicated that analysis of molecular markers, such as PIK3R1, could help select patients with actinic keratoses who demonstrate the best response to daylight PDT. Novel delivery protocols include artificial daylight, and laser-assisted and textile PDT. The meeting learnt of novel indications including antimicrobial PDT, as well as methods to optimise daylight PDT, including combination therapy for actinic keratoses. Adverse events were reviewed and options for painless and efficient PDT assessed, including the effect of reduced drug-light interval. A smartphone application was also evaluated which may be used to assist clinicians and patients in effective dosing and timing of daylight PDT via computational algorithms using data from earth observation satellites, to send light and ultraviolet dose information directly to patients' smart phones.

Good Places to Live and Sleep Well: A Literature Review About the Role of Architecture in Determining Non-Visual Effects of Light

Light plays a crucial role in affecting the melatonin secretion process, and consequently the sleep-wake cycle. Research has demonstrated that the main characteristics of lighting affecting the so-called circadian rhythms are spectrum, light levels, spatial pattern and temporal pattern (i.e., duration of exposure, timing and previous exposure history). Considering that today people spend most of their time in indoor environments, the light dose they receive strictly depends on the characteristics of the spaces where they live: location and orientation of the building, dimensions of the windows, presence of external obstructions, geometric characteristics of the space, optical properties of walls and furniture. Understanding the interaction mechanism between light and architecture is fundamental to design non-visually comfortable spaces. The goal of the paper is to deepen this complex issue. It is divided into two parts: a brief historical excursus about the relationship between lighting practice and architecture throughout the centuries and a review of the available research works about the topic. The analysis demonstrates that despite the efforts of the research, numerous open questions still remain, and they are mostly due to the lack of a shared and clear method to evaluate the effects of lighting on circadian rhythm regulation.

Daylight Photodynamic Therapy: An Update

Daylight photodynamic therapy (dPDT) uses sunlight as a light source to treat superficial skin cancer. Using sunlight as a therapeutic device has been present for centuries, forming the basis of photodynamic therapy in the 20th century. Compared to conventional PDT, dPDT can be a less painful, more convenient and an effective alternative. The first clinical uses of dPDT on skin cancers began in Copenhagen in 2008. Currently, aminolevulinic acid-mediated dPDT has been approved to treat actinic keratosis patients in Europe. In this review article, we introduce the history and mechanism of dPDT and focus on the pros and cons of dPDT in treating superficial skin cancers. The future applications of dPDT on other skin diseases are expected to expand as conventional PDT evolves.

Cones Support Alignment to an Inconsistent World by Suppressing Mouse Circadian Responses to the Blue Colors Associated with Twilight

In humans, short-wavelength light evokes larger circadian responses than longer wavelengths [1-3]. This reflects the fact that melanopsin, a key contributor to circadian assessments of light intensity, most efficiently captures photons around 480 nm [4-8] and gives rise to the popular view that "blue" light exerts the strongest effects on the clock. However, in the natural world, there is often no direct correlation between perceived color (as reported by the cone-based visual system) and melanopsin excitation. Accordingly, although the mammalian clock does receive cone-based chromatic signals [9], the influence of color on circadian responses to light remains unclear. Here, we define the nature and functional significance of chromatic influences on the mouse circadian system. Using polychromatic lighting and mice with altered cone spectral sensitivity (Opn1mw^R), we generate conditions that differ in color (i.e., ratio of L- to S-cone opsin activation) while providing identical melanopsin and rod activation. When biased toward S-opsin activation (appearing "blue"), these stimuli reliably produce weaker circadian behavioral responses than those favoring L-opsin ("yellow"). This influence of color (which is absent in animals lacking cone phototransduction; Cnga3^-/-) aligns with natural changes in spectral composition over twilight, where decreasing solar angle is accompanied by a strong blue shift [9-11]. Accordingly, we find that naturalistic color changes support circadian alignment when environmental conditions render diurnal variations in light intensity weak/ambiguous sources of timing information. Our data thus establish how color contributes to circadian entrainment in mammals and provide important new insight to inform the design of lighting environments that benefit health.

Children's Health in the Digital Age

Environmental studies, metabolic research, and state of the art research in neurobiology point towards the reduced amount of natural day and sunlight exposure of the developing child, as a consequence of increasingly long hours spent indoors online, as the single unifying source of a whole set of health risks identified worldwide, as is made clear in this review of currently available literature. Over exposure to digital environments, from abuse to addiction, now concerns even the youngest (ages 0 to 2) and triggers, as argued on the basis of clear examples herein, a chain of interdependent negative and potentially long-term metabolic changes. This leads to a deregulation of the serotonin and dopamine neurotransmitter pathways in the developing brain, currently associated with online activity abuse and/or internet addiction, and akin to that found in severe substance abuse syndromes. A general functional working model is proposed under the light of evidence brought to the forefront in this review.

The Impact of Optimized Daylight and Views on the Sleep Duration and Cognitive Performance of Office Workers

A growing awareness has recently emerged on the health benefits of exposure to daylight and views. Daylight exposure is linked to circadian rhythm regulation, which can have significant impacts on sleep quality and cognitive function. Views of nature have also been shown to impact emotional affect and performance. This study explores the impact of optimized daylight and views on the sleep and cognitive performance of office workers. Thirty knowledge workers spent one week working in each of two office environments with identical layouts, furnishings, and orientations; however, one was outfitted with electrochromic glass and the other with traditional blinds, producing lighting conditions of 40.6 and 316 equivalent melanopic lux, respectively. Participants in the optimized daylight and views condition slept 37 min longer as measured by wrist-worn actigraphs and scored 42% higher on cognitive simulations designed to test their higher order decision-making performance. Both sleep and cognitive function were impacted after one day in the space, yet the impacts became more significant over the course of the week. The positive effect of optimized daylight and views on cognitive function was comparable for almost all participants, while increases in sleep duration were significantly greater for those with the lowest baseline sleep duration. This study stresses the significance of designing with daylight in order to optimize the sleep quality and performance of office workers.

Protective effects of increased outdoor time against myopia: a review

Myopia has become a major cause for concern globally, particularly in East Asian countries. The increasing prevalence of myopia has been associated with a high socioeconomic burden owing to severe ocular complications that may occur with progressive myopia. There is an urgent need to identify effective and safe measures to address the growing number of people with myopia in the general population. Among the numerous strategies implemented to slow the progression of myopia, longer time spent outdoors has come to be recognized as a protective factor against this disorder. Although our understanding of the protective effects of outdoor time has increased in the past decade, considerably more research is needed to understand the mechanisms of action. Here, we summarize the main potential factors associated with the protective effects against myopia of increased outdoor time, namely, exposure to elevated levels and shorter wavelengths of light, and increased dopamine and vitamin D levels. In this review, we aimed to identify safe and effective therapeutic interventions to prevent myopia-related complications and vision loss.

Measuring Daylight: A Review of Dosimetry in Daylight Photodynamic Therapy

Successful daylight photodynamic therapy (DPDT) relies on the interaction of light, photosensitisers and oxygen. Therefore, the 'dose' of light that a patient receives during treatment is a clinically relevant quantity, with a minimum dose for effective treatment recommended in the literature. However, there are many different light measurement methods used in the published literature, which may lead to confusion surrounding reliable and traceable dose measurement in DPDT, and what the most appropriate method of light measurement in DPDT might be. Furthermore, for the majority of practitioners who do not carry out any formal dosimetry and for the patients receiving DPDT, building confidence in the evidence supporting this important treatment option is of key importance. This review seeks to clarify the methodology of DPDT and discusses the literature relating to DPDT dosimetry.

Clinical utility of daylight photodynamic therapy in the treatment of actinic keratosis - a review of the literature

Actinic keratosis (AK) is an early in situ squamous cell carcinoma that results from UV light exposure and has the potential to evolve into invasive tumor. Therefore, it is crucial that AKs are monitored and treated appropriately. Photodynamic therapy (PDT) is a treatment option that is minimally invasive and leaves patients with cosmetically superior results. However, disadvantages of PDT include pain and lengthy clinic visits. Accordingly, there has been much interest in the use of daylight photodynamic therapy (daylight-PDT) as a more convenient and less painful alternative to conventional photodynamic therapy (c-PDT). Current evidence shows that daylight-PDT is noninferior to c-PDT in the short and long term. Patients reported decreased pain with daylight-PDT and were more satisfied with the procedure (P<0.001). Current evidence suggests that 2 hrs of daylight exposure was sufficient for treatment, and its efficacy does not appear to be limited by weather conditions. Given the decreased intensity of treatment, daylight-PDT is better for mild disease, as it is less effective in moderate-to-thick AKs. Though further studies are still needed to refine the technique, daylight-PDT is a potential alternative to c-PDT for thin-to-moderate AKs and should be offered to patients with lower pain tolerance or busy schedules.

The Conceptualization of the Natural Environment in Healthcare Facilities: A Scoping Review

OBJECTIVES

To identify how the natural environment (NE) in healthcare has been conceptualized.

BACKGROUND

The NE appears to afford significant therapeutic benefits. A clear concept of the NE in healthcare affords a shared understanding from which to advance science to facilitate comparisons across contexts. In this article, the various meanings of the NE were brought together into one framework by which to map its themes and their relationships.

METHOD

A scoping review was conducted using database searches in MEDLINE, EMBASE, PsycINFO, CINAHL, and Cochrane for articles published up to July 2018. The bibliography of the included articles were manually searched for published books.

RESULTS

This review includes 137 peer-reviewed articles and research-based books from 27 countries. A conceptual framework was developed to identify five themes that conceptualize the NE in healthcare: (1) definitions of the NE in healthcare, (2) processes of the NE in healthcare, (3) usages of the NE in healthcare, (4) opinions about the NE in healthcare, and (5) NE's impacts on health and work outcomes in healthcare. These themes are filtered by the NE's physical and programmatic designs; changes in one affect the others. Definitions of the NE are described as human-made space, located in the indoors and outdoors, containing elements of nature and designed with the purpose to positively influence humans. Processes are described as the participatory approach in NE's development and its therapeutic goals. Usages are categorized into nature contact, frequency of usage, and accessibility. Opinions are accounted for by perceptions, preference, and satisfaction. Outcomes are related to physical health, mental health and well-being and work.

CONCLUSIONS

This framework contributes to the conceptual discussion and emphasizes NE's complementarity to the biomedical healthcare system.

The associations of daylight and melatonin receptor 1B gene rs10830963 variant with glycemic traits: the prospective PPP-Botnia study

BACKGROUND

Seasonal variation in glucose metabolism might be driven by changes in daylight. Melatonin entrains circadian regulation and is directly associated with daylight. The relationship between melatonin receptor 1B gene variants with glycemic traits and type 2 diabetes is well established. We studied if daylight length was associated with glycemic traits and if it modified the relationship between melatonin receptor 1B gene rs10830963 variant and glycemic traits.

MATERIALS

A population-based sample of 3422 18-78-year-old individuals without diabetes underwent an oral glucose tolerance test twice, an average 6.8 years (SD = 0.9) apart and were genotyped for rs10830963. Daylight data was obtained from the Finnish Meteorological Institute.

RESULTS

Cross-sectionally, more daylight was associated with lower fasting glucose, but worse insulin sensitivity and secretion at follow-up. Longitudinally, individuals studied on lighter days at follow-up than at baseline showed higher glucose values during the oral glucose tolerance test and lower Corrected Insulin Response at follow-up. GG genotype carriers in the rs10830963 became more insulin resistant during follow-up if daylight length was shorter at follow-up than at baseline.

CONCLUSIONS

Our study shows that individual glycemic profiles may vary according to daylight, MTNR1B genotype and their interaction. Future studies may consider taking daylight length into account. Key messages In Western Finland, the amount daylight follows an extensive annual variation ranging from 4 h 44 min to 20 h 17 min, making it ideal to study the associations between daylight and glycemic traits. Moreover, this allows researchers to explore if the relationship between the melatonin receptor 1B gene rs10830963 variant and glycemic traits is modified by the amount of daylight both cross-sectionally and longitudinally. This study shows that individuals, who participated in the study on lighter days at the follow-up than at the baseline, displayed to a greater extent worse glycemic profiles across the follow-up. Novel findings from the current study show that in the longitudinal analyses, each addition of the minor G allele of the melatonin receptor 1B gene rs10830963 was associated with worsening of fasting glucose values and insulin secretion across the 6.8-year follow-up. Importantly, this study shows that in those with the rs10830963 GG genotype, insulin sensitivity deteriorated the most significantly across the 6.8-year follow-up if the daylight length on the oral glucose tolerance testing date at the follow-up was shorter than at the baseline. Taken together, the current findings suggest that the amount of daylight may affect glycemic traits, especially fasting glucose and insulin secretion even though the effect size is small. The association can very according to the rs10830963 risk variant. Further research is needed to elucidate the mechanisms behind these associations.

Seasonal and dietary effects on Vitamin D deficiencies detected in wild boar from mid-western Spain

Vitamin D (VitD) is involved in important mammalian physiological mechanisms, such as Ca-P metabolism, bone development and immunological response. VitD deficiencies are frequently detected in domestic animals and related to various health problems (e.g., rickets, bone deformation). However, knowledge about the status of VitD in wildlife species, such as the wild boar, is scarce. The aims of this work were to explore VitD status in wild boar populations from mid-western Spain and to elucidate the influence of daylight exposure and food supplementation in levels of VitD. Serum concentration of VitD (measured as 25-hydroxivitaminD) was assessed in 276 wild boar from 27 game estates located in mid-western Spain using a commercial ELISA kit. In 19 out of 27 estates, the staff supplied a specific VitD-enriched food (2,000 UI/Kg) ad libitum throughout the year, while in the remaining estates (8), no food was supplied. Blood samples were extracted from hunted animals (198) between October and February of hunting seasons 2016/2017 and 2017/2018, and from live wild boar (78) that were captured, sampled and released (March-September of 2017). The percentage of animals with VitD deficiency (<20 ng/ml), VitD insufficiency (20-30 ng/ml) and VitD sufficiency (>30 ng/ml) was estimated, and the relationship of these levels to factors like sex, age and season was assessed using chi-square tests. Furthermore, associations between daylight exposure and supplemental food with VitD levels were explored using linear models. Of the studied wild boar population, 82.2% showed a VitD deficiency or insufficiency. VitD deficiencies were more frequent in animals sampled in winter and spring. Furthermore, levels of VitD positively correlated with daylight exposure and supplemental food intake. Ad libitum supplementation with VitD-enriched food was insufficient to prevent VitD deficiencies in wild boar from November to April, probably because food consumption is lower during this period.

Preclinical Evaluation of White Led-Activated Non-porphyrinic Photosensitizer OR141 in 3D Tumor Spheroids and Mouse Skin Lesions

Photodynamic therapy (PDT) is used to treat malignancies and precancerous lesions. Near-infrared light delivered by lasers was thought for a while to be the most appropriate option to activate photosensitizers, mostly porphyrins, in the depth of the diseased tissues. More recently, however, several advantages including low cost and reduced adverse effects led to consider light emitting diodes (LED) and even daylight as an alternative to use PDT to treat accessible lesions. In this study we examined the capacity of OR141, a recently identified non-porphyrin photosensitizer (PS), to exert significant cytotoxic effects in various models of skin lesions and tumors upon white light activation. Using different cancer cell lines, we first identified LED lamp as a particularly suited source of light to maximize anti-proliferative effects of OR141. We then documented that OR141 diffusion and light penetration into tumor spheroids both reached thresholds compatible with the induction of cell death deep inside these 3D culture models. We further identified Arlasove as a clinically suitable solvent for OR141 that we documented by using Franz cells to support significant absorption of the PS through human skin. Finally, using topical but also systemic administration, we validated growth inhibitory effects of LED-activated OR141 in mouse skin tumor xenograft and precancerous lesions models. Altogether these results open clinical perspectives for the use of OR141 as an attractive PS to treat superficial skin malignant and non-malignant lesions using affordable LED lamp for photoactivation.

How Enclosure and Spatial Organization Affect Residents' Use and Experience of a Dementia Special Care Unit: A Case Study

AIM:

We aim to gain insight into how a dementia special care unit is used and experienced by its residents and what design aspects are important therein.

BACKGROUND:

In Flanders, housing for people with dementia evolves toward small-scale, homelike environments. As population aging challenges the affordability of this evolution, architects and other designers are asked to design dementia special care units that offer the advantages of small scaleness within the context of large-scale residential care facilities. How these units are used and experienced is not systematically evaluated.

METHOD:

A case study was conducted in a recently built residential care facility where a dementia special care unit was foreseen on the ground floor, yet after a few months was moved to the top floor. The case study combined architectural analysis, participant observation, and qualitative interviews with residents and care staff.

RESULTS:

Comparing the original situation on the ground floor with the new situation on the top floor highlights how enclosure (physical and visual access to outside and the rest of the facility) and spatial organization affect how residents use and experience a dementia special care unit.

CONCLUSIONS:

Depending on the type and stage of dementia, residents may have different needs for space to move, sensory stimuli, and social contact. In order to meet these different needs, confining residents to a dementia special care unit to the top floor should be avoided unless it is carefully designed, providing sufficient freedom of movement and connection with the outside world.

Daylight photodynamic therapy for the treatment of actinic cheilitis

BACKGROUND

Actinic cheilitis (AC) is a common, chronic premalignant condition resulting from protracted sun exposure affecting the vermilion border of the lower lip. Treatment of AC aims at terminating the progression to squamous cell carcinoma by obliterating the primary lesion, and includes ablative methods; nonablative modalities such as cryotherapy, electrodessication, chemical peeling, topical imiquimod and 5-fluorouracil; and photodynamic therapy (PDT). Daylight-activated PDT, in which natural daylight serves as the light source, showed promising results in the treatment of actinic keratoses with substantially less pain than conventional PDT.

PURPOSE

To determine the safety and efficacy of daylight PDT in a series of patients with AC.

METHODS

Eleven patients with AC were treated with daylight PDT. All patients underwent repeated treatment sessions until clinical and histological remission were achieved.

RESULTS

Cure rate was 91% (10 of 11 patients, three females/eight males; mean age 59.2 ± 14.4 years). Mean number of treatments to attain cure was 2.7. Patients experienced mild erythema and minimal to no pain during treatment.

CONCLUSIONS

Daylight PDT is a promising modality for the treatment of AC, with impressive cosmetic results and few side effects.

Pilot study to examine the effects of indoor daylight exposure on depression and other neuropsychiatric symptoms in people living with dementia in long-term care communities

A 12-week study was conducted in eight dementia care communities involving 77 participants addressing the hypothesis that an intervention of increasing indoor exposure to daylight will reduce depression and other neuropsychiatric symptoms. At four communities, staff were enlisted to increase daylight exposure by taking participants to a perimeter room with daylight exposure for socialization in the morning (8:00-10:00 AM) each day. At the other four communities, a control group were taken to a similar sized area without daylight for socialization under typical electrical lighting conditions. Participants in the daylight intervention experienced an average decrease over the trial in the Neuropsychiatric Inventory Nursing Home Version (NPI-NH) scores (p=0.33) and the Cornell Scale for Depression in Dementia (CSDD) scores (p=0.025), while the control participants showed average but nonsignificant increases in both NPI-NH (p=0.33) and CSDD (p=0.13). Difference in outcome changes of the intervention group achieved statistical significance for CSDD (p=0.01) but not for NPI-NH (p=0.17). Our results suggest that increased exposure to daylight can reduce depression in people living with dementia.

Bright Light Delights: Effects of Daily Light Exposure on Emotions, Restactivity Cycles, Sleep and Melatonin Secretion in Severely Demented Patients

OBJECTIVE

We tested whether the effects of a dynamic lighting system are superior to conventional lighting on emotions, agitation behaviour, quality of life, melatonin secretion and circadian restactivity cycles in severely demented patients. As a comparison, an age matched control patient group was exposed to conventional lighting. For none of the output measures were significant differences between the two lighting conditions found during the 8 study weeks in fall/winter.

METHODS

Thus, we divided the patient cohort (n = 89) into two groups, solely based on the median of their daily individual light exposure. Patients with higher average daily light exposure (>417 lx) showed significantly longer emotional expressions of pleasure and alertness per daily observations than patients with lower daily light exposure. Moreover, they had a higher quality of life, spent less time in bed, went to bed later and initiated their sleep episodes later, even though the two groups did not differ with respect to age, severity of cognitive impairment and mobility. In general, men were more agitated, had shorter sleep with more wake episodes, had a lower circadian amplitude of relative rest-wake activity and interdaily circadian stability than women. In particular, lower daily light exposures significantly predicted lower circadian amplitudes of rest-activity cycles in men but not in women. This may indicate sex specific susceptibility to daily light exposures for rest-activity regulation in older demented patients.

RESULTS

Our results provide evidence that a higher daily light exposure has beneficial effects on emotions and thus improved quality of life in a severely demented patient group.

Seasonal Differences in Light Exposure and the Associations With Health and Well-Being in Older Adults: An Exploratory Study

OBJECTIVE

This article reports summer verses winter seasonal variations across a suite of blue light, illuminance levels and health and well-being indicators.

BACKGROUND

The quality of lighting in care homes has been assessed previously, yet seasonal comparisons and the associations with sleep quality are limited. This exploratory study investigates light exposure in two seasons to determine the changes over time and the associations with health and well-being.

METHODS

In a repeated measures design, 16 older people (aged 72-99 years) living in a care home had their personal light exposure and sleep/wake patterns monitored for 4 days. Cognitive ability, mental well-being, daytime physical activity, and visual function were assessed. Mean light levels at preset times across the day, duration in light exposure over 1,000 lux, and sleep parameters were computed. Statistical investigations included correlations exploring associations and paired means tests to detect the changes between seasons.

RESULTS

The mean morning illuminance level in summer was 466 lux and 65 lux in winter. Duration in bright light over 1,000 lux was 46 min in summer and 3 min in winter. Light measures were significantly higher in summer. There was no statistical difference in sleep quality parameters between seasons, but there were significant difference in daytime physical activity level (i.e., this was higher in summer).

CONCLUSION

The findings indicate low level of light exposures experienced in both seasons, with exposure levels being particularly low in winter. This provides new insights into the limited amount of light older people receive independent of season and the possible impacts on sleep and daytime physical activity level.

Melanopsin-Mediated Acute Light Responses Measured in Winter and in Summer: Seasonal Variations in Adults with and without Cataracts

Seasonal adaptation is a ubiquitous behavior seen in many species on both global hemispheres and is conveyed by changing photoperiods. In humans this seasonal adaptation is less apparent, in part because changes in daylength are masked by the use of electrical lighting at night. On the other hand, cataracts which reduce light transmission, may compound seasonal changes related to the reduced daylength of winter. To better understand the effects of different photoperiod lengths in healthy adults without and with cataracts, we tested their melanopsin-mediated light responses in summer vs. winter. Fifty-two participants (mean age 67.4 years; 30 with bilateral cataracts and 22 age-matched controls with clear lenses; pseudophakes) were tested twice, once in summer and once in winter. At each test session we assessed the electroretinogram and pupil responses during daytime and we determined melatonin suppression, subjective sleepiness and mood in response to light exposure in the evening. Circadian rest-activity cycles and sleep from activity recordings were also analyzed for both seasons. Both groups had similar visual function. There were no seasonal differences in the electroretinogram. For the pupil responses to bright blue light, the post-illumination pupil response (PIPR) was greater in winter than summer in pseudophakes, but not in cataract participants, whereas melatonin suppression to acute light exposure showed no differences between both groups and seasons. Overall, intra-daily variability of rest-activity was worse in winter but participants felt sleepier and reported worse mood at the laboratory in evening time in the summer. Those with cataracts had poorer sleep quality with lower sleep efficiency, and higher activity during sleep in winter than summer. In this study, the PIPR showed a seasonal variation in which a larger response was found during winter. This variation was only detected in participants with a clear intraocular lens. In the cataract group, visual function was not impaired yet these participants showed a lack of seasonal changes in the pupil response to blue light and poorer sleep in winter. These findings raise the question for tailored lighting conditions for cataract patients in order to counter potentially deleterious effects of living with chronically lower light exposure.

Improved color constancy in honey bees enabled by parallel visual projections from dorsal ocelli

How can a pollinator, like the honey bee, perceive the same colors on visited flowers, despite continuous and rapid changes in ambient illumination and background color? A hundred years ago, von Kries proposed an elegant solution to this problem, color constancy, which is currently incorporated in many imaging and technological applications. However, empirical evidence on how this method can operate on animal brains remains tenuous. Our mathematical modeling proposes that the observed spectral tuning of simple ocellar photoreceptors in the honey bee allows for the necessary input for an optimal color constancy solution to most natural light environments. The model is fully supported by our detailed description of a neural pathway allowing for the integration of signals originating from the ocellar photoreceptors to the information processing regions in the bee brain. These findings reveal a neural implementation to the classic color constancy problem that can be easily translated into artificial color imaging systems.

Daylight photodynamic therapy in Scotland

Chronic sun-induced dysplastic skin changes (actinic keratoses) are extremely common in fair-skinned people in Scotland. These changes are a major cause of morbidity and may develop into skin cancer. Actinic keratoses are often extensive and pose a therapeutic challenge as field-directed treatment is required for chronic disease management. One such treatment approach is hospital-based photodynamic therapy, which is a well-established treatment in Scotland for actinic keratoses, using a photosensitiser pro-drug and red LED light irradiation. However, photodynamic therapy using daylight as the activating light source is increasingly and effectively used in continental Europe, but had not been explored in Scotland until we initiated this in 2013. We report our experience of daylight photodynamic therapy in 64 patient-treatment courses and demonstrate that this can be an effective, well-tolerated treatment, which is liked by patients. Our most recent data show that most patients (73%) achieved clearance or at least a good response to treatment and had high levels of satisfaction with daylight photodynamic therapy. Daylight exposure measurements indicated that treatment is feasible in Scotland between April to September. Daylight photodynamic therapy is an important advancement in treatment options for Scottish patients with extensive pre-cancerous field changes and provides opportunities for home-based treatment and increased efficiency of photodynamic therapy services.

Diurnal and seasonal occurrence of febrile seizures

BACKGROUND

Febrile seizures are the most common seizures in children, but their pathogenesis remains unknown. Some studies have suggested an association between the light-dependent secretion of melatonin and the occurrence of febrile seizures. The diurnal and seasonal occurrence of febrile seizures could clarify the role daylight plays in febrile seizures.

METHODS

In Finland, summer days are long and bright and winter days are short and dark. We evaluated the diurnal and seasonal occurrence of the first febrile seizures in 461 children and adjusted them according to the epidemiology of the febrile episodes in a population-based study of 1522 children.

RESULTS

The first febrile seizure most often occurred in the evening, peaking between 6 and 10 PM (31%), and least often at night, in the early morning hours between 2 and 6 AM (8%) (P < 0.001). This diurnal pattern repeated itself in different seasons according to variance in daylight duration. Febrile seizures occurred irregularly throughout the year, most frequently in winter, concurrently with the febrile episodes, and least frequently in summer; this seasonal variation in the occurrence of febrile seizures disappeared however when adjusted for the number of febrile events.

CONCLUSIONS

We found clear diurnal and seasonal variations in the occurrence of febrile seizures, even though they did not follow the amount of daylight. Our findings do not support the hypothesis that the diurnal and seasonal variation of daylight explains the occurrence of febrile seizures. Moreover, febrile events associated strongly with the occurrence of febrile seizures.

Enhanced Photocatalytic Degradation of Methyl Orange Dye under the Daylight Irradiation over CN-TiO₂ Modified with OMS-2

In this study, CN-TiO₂ was modified with cryptomelane octahedral molecular sieves (OMS-2) by the sol-gel method based on the self-assembly technique to enhance its photocatalytic activity under the daylight irradiation. The synthesized samples were characterized by X-ray diffraction (XRD), UV-vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and porosimeter analysis. The results showed that the addition of OMS-2 in the sol lead to higher Brunauer-Emmett-Teller (BET) surface area, pore volume, porosity of particle after heat treatment and the specific surface area, porosity, crystallite size and pore size distribution could be controlled by adjusting the calcination temperature. Compared to the CN-TiO₂-400 sample, CN-TiO₂/OMS-2-400 exhibited greater red shift in absorption edge of samples in visible region due to the OMS-2 coated. The enhancement of photocatalytic activity of CN-TiO₂/OMS-2 composite photocatalyst was subsequently evaluated for the degradation of the methyl orange dye under the daylight irradiation in water. The results showed that the methyl orange dye degradation rate reach to 37.8% for the CN-TiO₂/OMS-2-400 sample under the daylight irradiation for 5 h, which was higher than that of reference sample. The enhancement in daylight photocatalytic activities of the CN-TiO₂/OMS samples could be attributed to the synergistic effects of OMS-2 coated, larger surface area and red shift in adsorption edge of the prepared sample.

Light and chronobiology: implications for health and disease

Environmental light synchronizes the primary mammalian biological clock in the suprachiasmatic nuclei, as well as many peripheral clocks in tissues and cells, to the solar 24-hour day. Light is the strongest synchronizing agent (zeitgeber) for the circadian system, and therefore keeps most biological and psychological rhythms internally synchronized, which is important for optimum function. Circadian sleep-wake disruptions and chronic circadian misalignment, as often observed in psychiatric and neurodegenerative illness, can be treated with light therapy. The beneficial effect on circadian synchronization, sleep quality, mood, and cognitive performance depends on timing, intensity, and spectral composition of light exposure. Tailoring and optimizing indoor lighting conditions may be an approach to improve wellbeing, alertness, and cognitive performance and, in the long term, producing health benefits.

Day length and weather effects on children's physical activity and participation in play, sports, and active travel

BACKGROUND

Children in primary school are more physically active in the spring/summer. Little is known about the relative contributions of day length and weather, however, or about the underlying behavioral mediators.

METHODS

325 British children aged 8 to 11 wore accelerometers as an objective measure of physical activity, measured in terms of mean activity counts. Children simultaneously completed diaries in which we identified episodes of out-of-home play, structured sports, and active travel. Our main exposure measures were day length, temperature, rainfall, cloud cover, and wind speed.

RESULTS

Overall physical activity was higher on long days (≥ 14 hours daylight), but there was no difference between short (< 9.5 hours) and medium days (10.2-12.6 hours). The effect of long day length was largest between 5 PM and 8 PM, and persisted after adjusting for rainfall, cloud cover, and wind. Up to half this effect was explained by a greater duration and intensity of out-of-home play on long days; structured sports and active travel were less affected by day length.

CONCLUSIONS

At least above a certain threshold, longer afternoon/evening daylight may have a causal role in increasing child physical activity. This strengthens the public health arguments for daylight saving measures such as those recently under consideration in Britain.

Measuring circadian light and its impact on adolescents

A field study was conducted with eighth-grade students to determine the impact of morning light on circadian timing, sleep duration and performance. Before and during school hours for a week in February 2009, half the students studied wore orange glasses that minimized short-wavelength light exposure needed for circadian system stimulation. A control group did not wear the orange glasses. The Daysimeter, a circadian light meter, measured light/dark exposures in both groups for seven days. Circadian timing was significantly delayed for those students who wore orange glasses compared to the control group. Sleep durations were slightly, but not significantly, curtailed in the orange-glasses group. Performance scores on a brief, standardized psychomotor vigilance test and self-reports of well-being were not significantly different between the two groups.

Lack of short-wavelength light during the school day delays dim light melatonin onset (DLMO) in middle school students

OBJECTIVE

Circadian timing affects sleep onset. Delayed sleep onset can reduce sleep duration in adolescents required to awake early for a fixed school schedule. The absence of short-wavelength ("blue") morning light, which helps entrain the circadian system, can hypothetically delay sleep onset and decrease sleep duration in adolescents. The goal of this study was to investigate whether removal of short-wavelength light during the morning hours delayed the onset of melatonin in young adults.

METHODS

Dim light melatonin onset (DLMO) was measured in eleven 8th-grade students before and after wearing orange glasses, which removed short-wavelength light, for a five-day school week.

RESULTS

DLMO was significantly delayed (30 minutes) after the five-day intervention, demonstrating that short-wavelength light exposure during the day can be important for advancing circadian rhythms in students.

CONCLUSIONS

Lack of short-wavelength light in the morning has been shown to delay the circadian clock in controlled laboratory conditions. The results presented here are the first to show, outside laboratory conditions, that removal of short-wavelength light in the morning hours can delay DLMO in 8th-grade students. These field data, consistent with results from controlled laboratory studies, are directly relevant to lighting practice in schools.