Duration Of Light Exposure Research Articles

Practical application of PMA-qPCR assay for determination of viable cells of inter-species biofilm of Candida albicans-Staphylococcus aureus

Abstract Determining the number of viable cells by calculating colony-forming units is time-consuming. The evaluation of mixed biofilms consisting of different species is particularly problematic. Therefore, the aim of this study was to optimize a molecular method—propidium monoazide quantitative polymerase chain reaction (PMA-qPCR) - for accurate and consistent differentiation between living and dead cells. In the practical experimental example, the number of genome copies representing living cells was determined in a mixed biofilm of Candida albicans-Staphylococcus aureus inhibited by photodynamic inactivation. Optimal conditions such as PMA concentration and the duration of light exposure, the optimization of DNA isolation from the mixed biofilm and standardization of PMA-qPCR parameters were tested prior to the main experiment. The genome copy number was calculated based on the known amount of gDNA in the qPCR reaction and the genome size of the respective microorganism. The results showed that PDI in the presence of 1 mM methylene blue decreased the total genome copy number from 1.65x108 to 3.19x107, and from 4.39x107 to 1.91x107 for S. aureus and C. albicans (p < 0.01), respectively. The main disadvantage is overestimation of the number of living cells represented by genome copy numbers. Such cells are unable to reproduce and grow (no vitality), and are continuously dying. On the other hand, PMA-qPCR determines the copy numbers of all microbial species, including a mix of eukaryotic yeasts and prokaryotic bacteria in a biofilm in one step, which is a great advantage.

Application of Artificial Intelligence and Image Processing for the Cultivation of Chlorella sp. Using Tubular Photobioreactors.

By integrating innovative technologies to enhance the efficiency and sustainability of production, this study specifies the establishment of a cutting-edge growing system for Chlorella sp. microalgae. Improvement of a system for the real-time, noninvasive observation and management of algae growth employing a closed tubular photobioreactor (PBR) engineered with computational fluid dynamics (CFD), combined with the Internet of things (IoT), artificial intelligence (AI), and image processing technologies was the major goal of this research. The fitting of seven types of sensors to identify key characteristics such as temperature, pH, light intensity, electrical conductivity (EC), flow rate, oxygen content, and light exposure duration was included in the research method. To manage the gaining of sensor data and system operations, an ESP8266 microcontroller was used as the main control unit, while 33 × 33 pixel images were taken with an ESP32 camera at 30 min intervals to assess growth by evaluating color intensity, enabling real-time evaluation of algal density without sampling or disturbing growth. Forecasting and enhancing farming situations was the goal of producing these machine learning (ML) models. Uniformly dispersed between 12 and 24 h light cycles, the data set comprised 602 samples. Considerable improvements were observed in the results for biomass productivity, with constant 24 h lighting yielding a 7.19% increase, counter to a 2.09% increase seen in the 12 h cycle. Temperature and light intensity are the most significant parameters for growth, as revealed by analysis of Feature Importance. The eXtreme Gradient Boosting (XGBoost) model showed remarkable effectiveness in terms of projecting growth, attaining an R 2 value of 0.9997 for the training data set. With important benefits for the development of renewable energy, food supply, and environmental modification in the future, this research highlights the competence of intelligent technology to strengthen microalgae production.

Photoperiodic Effect on Growth, Photosynthesis, Mineral Elements, and Metabolome of Tomato Seedlings in a Plant Factory.

The duration of light exposure is a crucial environmental factor that regulates various physiological processes in plants, with optimal timing differing between species and varieties. To assess the effect of photoperiods on the growth and metabolites of a specific truss tomato cultivar, three photoperiods (12 h, 16 h, and 20 h) were tested in a plant factory. Growth parameters, including plant height, stem diameter, fresh and dry weights of shoots and roots, photosynthetic characteristics, mineral content, and metabolome profiles, were analyzed under these conditions. The results indicated that prolonged light exposure enhanced plant growth, with the highest photosynthesis and chlorophyll content observed under a 20 h photoperiod. However, no significant correlation was observed between the photoperiod and the mineral element content, particularly for macro minerals. Metabolome analysis revealed that different photoperiods influenced the accumulation of metabolites, particularly in the lipid metabolism, amino acid metabolism, and membrane transport pathways. Long periods of light would enhance photosynthesis and metabolism, improving the rapid growth of tomato seedlings. Overall, this study provides a theoretical basis for understanding the responses of truss tomato cultivars to varying photoperiods in plant factories and proposes an optimizable method for accelerating the progress of tomato seedling cultivation.

Comparison of BiliCocoon phototherapy with overhead phototherapy in hyperbilirubinemic neonates. A randomized clinical trial.

Around 2-6% of term or late preterm neonates receive phototherapy for hyperbilirubinemia. Standard treatment today is overhead phototherapy. A new device has been developed, the BiliCocoon, where the neonates are "wrapped" presumably making them more comfortable. The aim was to compare the efficacy and performance of the BiliCocoon with overhead LED phototherapy. A randomized open-label multicenter trial in three Danish neonatal units. Healthy hyperbilirubinemic neonates, gestational age ≥33 weeks and postnatal age 24 h to 14 days were randomized to 24 hours' of treatment with BiliCocoon or overhead blue LED phototherapy with an equal level of irradiance. A mixed effect model with random effect by center was used to compare the percentage decrease in total serum bilirubin (TSB) between the treatments. Totally 83 neonates were included. Mean TSB reduction in the BiliCocoon group (N = 42), adjusted for baseline TSB, was significantly lower than in the overhead LED group (N = 41), 29% vs. 38% (p-value < 0.01). Overall difference in temperature by treatment (BiliCocoon vs overhead) was 0.70 [0.37; 1.02] °C, p-value < 0.01. Bilirubin reducing efficacy of BiliCocoon was lower than that of overhead phototherapy, but it was sufficient for nearly all neonates during 24 hours of treatment. The BiliCocoon has a bilirubin reducing efficacy, sufficient for almost all neonates during 24 hours of phototherapy. The BiliCocoon does not have an equal bilirubin reducing efficacy as overhead phototherapy. The duration of light exposure was longer for the neonates treated in the BiliCocoon. A few neonates can be exclusively breastfed in the BiliCocoon throughout the treatment. The reason for stopping breastfeeding in the BiliCocoon was most often, that the neonates developed hyperthermia.

Duration of Light Exposure Using White Light-Emitting Diode (LED) on the Performance of White Oyster Mushroom (Pleurotus ostreatus L.)

Background: In the dynamic world of mushroom cultivation, optimizing growth conditions is paramount for maximizing yield and quality. This research sought to evaluate the influence of varying hours of exposure to white light through light-emitting diodes (LED) on growth and yield performance of white oyster mushroom (Pleurotus ostreatus L.). Its aim was to determine the most effective light exposure duration for enhancing mushroom growth and yield. Research Design: Using a completely randomized design (CRD), the study used four treatments: 8 hours of lighting (T1), 12 hours of lighting (T2), 16 hours of lighting (T3), and a control group that received natural light (T4). The study was conducted in Palayamanan (8° 27’ 5.3118" N and 126° 9’ 59.7739" E) area at North Eastern Mindanao State University’s -Tagbina Campus from July 2023 to November 2023. Results: Results from the study provided interesting insights into the indirect nature of the relationship between light exposure and mushroom development. The findings of the study indicate that the duration of light exposure significantly affects the growth and yield of white oyster mushrooms. Both mycelium growth (29.80 days) and fruiting body formation (7.83 days), as well as harvesting time (10.87 days), were improved by 12 hours of lighting, while the control group consistently showed poor performance. Conclusion: Based from the analysis, it is evident that 12 hours of lighting consistently performed very well, with the exception of a minor under-performance in the case of yield per harvest, suggesting that 12 hours might be the ideal duration. Hence, 16 hours of lighting also demonstrated some advantages in certain variables, indicating potential for further study.

Corneal scarring after epithelium-off collagen cross-linking

Abstract Collagen cross-linking (CXL) is considered as a successful therapeutic approach for corneal conditions like keratoconus and corneal ectasia. Despite its efficacy in stabilizing these conditions, the occurrence of post-CXL scars remains a concern. Keratoconus and other corneal ectasias are characterized by structural weaknesses in the cornea. This weakness contributes to the vulnerability of corneal scar formation. In addition, corneal biomechanics and tissue properties play a significant role in scar development. Procedural factors during CXL, including duration and intensity of ultraviolet light exposure, the concentration and type of riboflavin, and the precise application of treatment, have been identified as potential causes of scar formation. Individual patient factors such as variations in healing response and genetic predispositions, associated ocular allergy, and chronic contact lens wear can also impact scar development post-CXL. Understanding these variables is essential for risk stratification and personalized treatment approaches, ultimately optimizing patient outcomes. In addition, regular follow-up visits and patient education are essential to ensure optimal healing and minimize scar related complications. We have tried to explain the numerous reasons of scarring following epithelium-off CXL by conducting a thorough Medline search and reviewing our clinical images. This review serves as a concise overview of the causes and risk factors associated with scar formation after epithelium-off CXL.

Developing and analyzing photo-crosslinkable cinnamoyl-modified pullulan hydrogels for drug delivery applications

A hydrogel created by modifying pullulan with cinnamoyl groups (Pul-CM) through an esterification process was developed as an effective vehicle for delivering the well-known drug model, caffeine. Initially, pullulan biopolymer was expanded, followed by the addition of cinnamoyl groups using cinnamoyl chloride. These modifications were confirmed through various spectroscopic and instrumental techniques, verifying their proposed chemical structures. The newly created Pul-CM hydrogel demonstrated the ability to crosslink without initiators when exposed to UV light for sufficient durations. This crosslinking is attributed to the creation of cyclobutane rings that link the pullulan chains via a [2π+2π] cyclization process facilitated by the cinnamoyl groups' –CH=CH– bonds. The progress of Pul-CM crosslinking was tracked by the reduction in the UV spectral peak associated with the cinnamate groups, followed by an examination of the gel's efficiency and its swelling behavior under UV light. Furthermore, these hydrogel derivatives show significant promise as drug delivery systems, offering adjustable drug release rates by altering the hydrogel's crosslinking level through either cinnamoyl modification or the duration of UV light exposure.

Virucidal activity of porphyrin-based metal-organic frameworks against highly pathogenic coronaviruses and hepatitis C virus

The antiviral effect of four porphyrin-based Metal-Organic Frameworks (PMOFs) with Al and Zr, namely Al-TCPP, PCN-222, PCN-223 and PCN-224 was assessed for the first time against HCoV-229E, two highly pathogenic coronaviruses (SARS-CoV-2 and MERS-CoV) and hepatitis C virus (HCV). Infection tests in vitro were done under dark or light exposure for different contact times, and it was found that 15 min of light exposure were enough to give antiviral properties to the materials, therefore inactivating HCoV-229E by 99.98 % and 99.96 % for Al-TCPP and PCN-222. Al-TCPP diminished the viral titer of SARS-CoV-2 greater than PCN-222 in the same duration of light exposure, having an effect of 99.95 % and 93.48 % respectively. Next, Al-TCPP was chosen as the best candidate possessing antiviral properties and was tested against MERS-CoV and HCV, showcasing a reduction of infectivity of 99.28 % and 98.15 % respectively for each virus. The mechanism of the antiviral activity of the four PMOFs was found to be the production of singlet oxygen 1O2 from the porphyrin ligand TCPP when exposed to visible light, by using sodium azide (NaN3) as a scavenger, that can later attack the phospholipids on the envelope of the viruses, thus preventing their entry into the cells.

Chemiluminescence method for evaluating photooxidative degradation of dispensed drugs: a potential new drug information tool

BackgroundDispensed drugs stored by patients are often in single-dose packages (SDPs) or are crushed and mixed after being removed from a press-through package (PTP) sheet. Information on their stability is extremely limited. To address this, we explored using chemiluminescence (CL) measurements to detect oxidative degradation.MethodsEight amlodipine, 14 telmisartan, and two warfarin preparations were used as specimens. These preparations were stored at room temperature under various conditions, after which CL was measured. Cellopoly packaging paper was used for SDP. Three light conditions were used (Condition A: darkness, Condition B: indoor diffused light (approximately 400 lx), and Condition C: exposure to 4,000 lx). CL cumulative light output was measured every minute under nitrogen gas conduction and with a sample chamber temperature of 150 °C, for a maximum of 10 min. Luminescence images were obtained simultaneously with the CL measurements.ResultsCL was observed on light-exposed tablet surfaces. For each preparation, an increase in the CL value was observed with the duration of light exposure. In the same preparation with the same exposure time, CL tended to be higher in the order of Condition A < B < C. Moreover, CL increased even when no changes in color were observed by the naked eye. A comparison between preparations with the same main ingredients showed differences in the rate of increase in CL with exposure, and each was found to show a different reactivity to light.ConclusionsTo the best of our knowledge, this is the first study to visually capture the surface oxidation of tablets exposed to light using the CL method. The CL values, thought to be derived from photooxidation, increased with exposure of tablets and powders to light after SDP. This method can sensitively assess drug degradation due to photooxidation. Further research is needed to establish a CL method for assessing the stability of preparations in clinical settings.

Combined Electrochemical Deposition and Photo-Reduction to Fabricate SERS-Active Silver Substrates: Characterization and Application for Malachite Green Detection in Aquaculture Water.

This research introduces a novel approach using silver (Ag) nanostructures generated through electrochemical deposition and photo-reduction of Ag on fluorine-doped tin oxide glass substrates (denoted as X-Ag-AgyFTO, where 'X' and 'y' represent the type of light source and number of deposited cycles, respectively) for surface-enhanced Raman spectroscopy (SERS). This study used malachite green (MG) as a Raman probe to evaluate the enhancement factors (EFs) in SERS-active substrates under varied fabrication conditions. For the substrates produced via electrochemical deposition, we determined a Raman EF of 6.15 × 104 for the Ag2FTO substrate. In photo-reduction, the impact of reductant concentration, light source, and light exposure duration were examined on X-Ag nanoparticle formation to achieve superior Raman EFs. Under optimal conditions (9.0 mM sodium citrate, 460 nm blue-LED at 10 W for 90 min), the combination of blue-LED-reduced Ag (B-Ag) and an Ag2FTO substrate (denoted as B-Ag-Ag2FTO) exhibited the best Raman EF of 2.79 × 105. This substrate enabled MG detection within a linear range of 0.1 to 1.0 µM (R2 = 0.98) and a detection limit of 0.02 µM. Additionally, the spiked recoveries in aquaculture water samples were between 90.0% and 110.0%, with relative standard deviations between 3.9% and 6.3%, indicating the substrate's potential for fungicide detection in aquaculture.

Light-Assisted Fabrication of Hierarchical Azopolymer Structures Using the Breath Figure Method and AAO Templates.

Hierarchical polymer structures have garnered widespread application across various fields owing to their distinct surface properties and expansive surface areas. Conventional hierarchical polymer structures, however, often lack postfabrication scalability and spatial selectivity. In this study, we propose a novel strategy to prepare light-assisted hierarchical polymer structures using azopolymers (PAzo), the breath figure method, and anodic aluminum oxide (AAO) templates. Initially, the breath figure PAzo films are prepared by dripping a PAzo chloroform solution onto glass substrates in a high-humidity environment. The AAO templates are then placed on the breath figure PAzo film. Upon ultraviolet (UV) light exposure, the azobenzene groups in the azopolymers undergo trans-cis photoisomerization. This process causes the glass transition temperature (Tg) of the PAzo to become lower than room temperature, allowing the azopolymer to enter the nanopores of the AAO templates. The hierarchical azopolymer structures are then formed by using a sodium hydroxide solution to remove the templates. Furthermore, exploring the effects of PAzo concentration and UV light exposure duration on the film morphology reveals optimized conditions for hierarchical structure formation. Additionally, the water contact angles of these polymer structures are measured. The hierarchical PAzo structures exhibit higher hydrophobicity compared with the flat PAzo films and the PAzo breath figure films. Finally, patterned breath figure films can be prepared using designed photomasks, demonstrating the method's capability for spatial selectivity.

Cost-effective, open-source light shutters with Arduino control

In optical experiments, shutters are devices that open or close a path of light. They are often used to limit the duration of light exposure onto a target or onto a detector to reduce possible light-induced damage. Many commercial shutters are available for different applications – some provide very fast opening and closing times, some can handle large optical powers, and others allow for fail-safe operation. Many of these devices are costly and offer limited control options. Here we provide an open-source design for a low-cost, general purpose shutter system based on ubiquitous actuators (servo motors or solenoids) that are connected to an Arduino-based controller. Several shutters can be controlled by one controller, further reducing system cost. The state of the shutters can be controlled via a display built into the controller, by serial commands via USB, or by electrical control lines. The use of a microcontroller makes the shutter controller adaptable – only control options that are used need to be included, and the design accommodates a selection of display and actuator options. We provide designs for all required components, including 3D print files for the actuator holders and cases, the Arduino code, libraries for serial communication (C and python), and example graphical user interfaces for testing.

Diverse Flowering Response to Blue Light Manipulation: Application of Electric Lighting in Controlled-Environment Plant Production

Blue light is an important light wavelength in regulating plant flowering. In a controlled environment (CE) plant production systems, blue light can be manipulated easily and even precisely through electric lighting, especially with the advancement of light-emitted diode (LED) technologies. However, the results of previous studies in the literature about blue-light-mediated flowering are inconsistent, which would limit its practical application in CE plant production while implying that an in-depth study of the relevant physiological mechanism is necessary in the future. This review consolidates and analyzes the diverse findings from previous studies on blue light-mediated plant flowering in varying high-value crops from ornamental plants to fruits, vegetables, and specialty crops. By synthesizing the contrasting results, we proposed the possible explanations and even the underlying mechanisms related to blue light intensity and exposure duration, its co-action with other light wavelengths, background environment conditions, and the involved photoreceptors. We have also identified the knowledge gaps based on these studies and outlined future directions for research and potential application in this promising field. This review provides valuable insights into the important and diverse role of blue light in plant flowering and offers a foundation for further investigations to optimize plant flowering through lighting technologies.

Evaluating the Potential of Green Light Exposure on Nociception-A Mini Review.

The capacity of animals to react to unpleasant stimuli that might endanger their integrity is known as nociception. Pharmacological treatments do not show satisfactory results in response to nociception. In the recent era, light therapy emerged as a potential non-pharmacological approach for treating various diseases, including seasonal affective disorders, migraine, pain, and others. Evaluating the potential of green light exposure on nociception involves studying its effects on different types of pain and pain-related conditions and determining the optimal exposure methods. This review provides the beneficial effects of green light on the reduction in the frequency of pain. The green light exposure on nociception changes the activity of pain-related genes and proteins in cells. This review could provide insights into the underlying mechanisms by which green light modulates pain. Overall, evaluating the potential of green light exposure on nociception requires a multidisciplinary approach and should consider the safety, efficacy, optimal dose, and duration of green light exposure and the type of pain. However, few studies have been reported so far; therefore, light therapy for treating migraines require more studies on animal models to provide precise results of light effects on nociception.

Optimal growth conditions to enhance Chlorella vulgaris biomass production in indoor phyto tank and quality assessment of feed and culture stock

Commercial microalgae cultivation is a dynamic field with ongoing efforts to improve efficiency, reduce costs, and explore new applications. We conducted a study to examine how different light exposure periods affect Chlorella vulgaris's growth. We employed a Phyto tank batch system of approximately 3.5 L with LED light control, controlled airflow, and sterilized bags, maintained at 22.0 ± 2.0 °C indoors. Various methods, including spectrophotometry, and cell counter were employed to monitor Chlorella vulgaris growth under different light exposure cycles. Additionally, quality analysis as feed source was employed by proximate, amino acid, beta-glucan, and microbial content analysis. The results revealed significant variations in C. vulgaris biomass production based on light exposure duration. Notably, the 16:8-h light-dark photoperiod exhibited the highest biomass concentration, reaching 6.48 × 107 ± 0.50 cells/mL with an optical density (OD) of 1.165 absorbance at 682 nm. The 12:12-h light-dark photoperiod produced the second-highest biomass concentration, with 2.305 × 106 ± 0.60 cells/mL at an OD of 0.489. Proximate analysis of dry algae powder revealed low lipid content (0.48 %), high protein content (37.61 %), variable ash concentration (average 10.75 %), and a significant carbohydrate fraction (51.16 %) during extended daylight and shorter dark periods. Amino acid analysis identified nine essential amino acids, with glutamic acid being the most abundant (17.7 %) and methionine the least (0.4 %). Furthermore, quality analysis and microbiological assays demonstrated that the C. vulgaris biomass is well-suited for fish and livestock use as a feed source and possibility as human nutraceuticals. These findings can be considered more environmentally friendly and ethically sound due to the absence of genetic modification.

Degradation and transformation mechanisms of pungent substances in huajiao (Zanthoxylum bungeanum) oil during storage: Induced by ultraviolet irradiation

The pungency of huajiao (scientifically known as Zanthoxylum bungeanum) oil (ZBO), a crucial seasoning oil, is notably influenced by storage conditions, an aspect insufficiently explored in current research. Through the use of high-performance liquid chromatography and liquid chromatography-mass spectrometry, this study systematically investigated the stability of pungent compounds in ZBO under various storage conditions. It also elucidated the degradation and transformation mechanisms of these substances when exposed to ultraviolet (UV) irradiation. The results underscore elevated temperature, light exposure, oxygen, and storage duration as pivotal factors influencing compound degradation, with UV light emerging as the primary driving force. After 48 h of UV exposure, the primary pungent compound, hydroxy-α-sanshool, experienced a significant loss of 85.49%, indicating a pronounced inclination towards isomerization and oxidation. Notably, this study reveals, for the first time, the possible degradation-transformation pattern of hydroxy-γ-sanshool: a mutual conversion with hydroxy-γ-isosanshool and isomerization to (2E,4E,8Z,10E,12Z)-N-(2-hydroxy-2-methylpropyl) tetradeca-2,4,8,10,12-pentaenamide.

Light-Emitting Diodes and Liquid System Affect the Caffeoylquinic Acid Derivative and Flavonoid Production and Shoot Growth of Rhaponticum carthamoides (Willd.) Iljin.

Plant in vitro cultures can be an effective tool in obtaining desired specialized metabolites. The purpose of this study was to evaluate the effect of light-emitting diodes (LEDs) on phenolic compounds in Rhaponticum carthamoides shoots cultured in vitro. R. carthamoides is an endemic and medicinal plant at risk of extinction due to the massive harvesting of its roots and rhizomes from the natural environment. The shoots were cultured on an agar-solidified and liquid-agitated Murashige and Skoog's medium supplemented with 0.1 mg/L of indole-3-acetic acid (IAA) and 0.5 mg/L of 6-benzyladenine (BA). The effect of the medium and different treatments of LED lights (blue (BL), red (RL), white (WL), and a combination of red and blue (R:BL; 7:3)) on R. carthamoides shoot growth and its biosynthetic potential was observed. Medium type and the duration of LED light exposure did not affect the proliferation rate of shoots, but they altered the shoot morphology and specialized metabolite accumulation. The liquid medium and BL light were the most beneficial for the caffeoylquinic acid derivatives (CQAs) production, shoot growth, and biomass increment. The liquid medium and BL light enhanced the content of the sum of all identified CQAs (6 mg/g DW) about three-fold compared to WL light and control, fluorescent lamps. HPLC-UV analysis confirmed that chlorogenic acid (5-CQA) was the primary compound in shoot extracts regardless of the type of culture and the light conditions (1.19-3.25 mg/g DW), with the highest level under R:BL light. BL and RL lights were equally effective. The abundant component was also 3,5-di-O-caffeoylquinic acid, accompanied by 4,5-di-O-caffeoylquinic acid, a tentatively identified dicaffeoylquinic acid derivative, and a tricaffeoylquinic acid derivative 2, the contents of which depended on the LED light conditions.

U-shaped relationship between lights-out time and nocturnal oxygen saturation during the first trimester: An analysis based on the nuMOM2b-SDB data

ObjectivePreventing adverse events due to unstable oxygen saturation (SpO2) at night in pregnant women is of utmost importance. Poor sleep has been demonstrated to impact SpO2 levels. Nowadays, many gravida have a habit of prolonged exposure to light before sleep, which can disrupt their sleep. Therefore, this study aimed at investigate the relationship between lights-out time, sleep parameters and SpO2, exploring the underlying mechanisms. MethodsThe data of 2881 eligible subjects from the Nulliparous Pregnancy Outcomes Study Monitoring Mothers-to-be and Sleep Disordered Breathing (nuMOM2b-SDB) database were analyzed. Multiple linear regression models were used to investigate the relationship between lights-out time and SpO2. In addition, restricted cubic splines (RCS) were employed to fit the nonlinear correlation between the two variables. The smoothing curve method was further utilized to depict the relationship between lights-out time and SpO2 based on various subgroup variables. ResultsAll participants were categorized according to race/ethnicity. A negative correlation was observed between nighttime lights-out time and average value of SpO2 (Avg-SpO2) (β = −0.05, p = 0.010). RCS revealed a U-shaped relationship between lights-out time and Avg-SpO2, with the turning point at 22:00. The subcomponent stratification results indicated that the Avg-SpO2 and minimum value of SpO2(Min-SpO2) of advanced maternal age decreased as the lights-out time was delayed. Furthermore, overweight and obese gravida showed lower Avg-SpO2 and Min-SpO2 levels than normal weight. ConclusionsA U-shaped relationship was identified between lights-out time and nocturnal Avg-SpO2 during early pregnancy, with the inflection at 22:00. Notably, later lights-out times are associated with lower levels of Min-SpO2 for advanced maternal age. The findings suggest that appropriately adjusting the duration of light exposure before sleep and maintaining a relatively restful state may be more beneficial for the stability of SpO2 in pregnant women. Conversely, deviations from these practices could potentially lead to pathological alterations in SpO2 levels.

462 Depression Moderates Independent Effects of Daily Natural Light Exposure and Activity on Daily Mood

OBJECTIVES/GOALS: Ambulatory methods are useful tools to study physical and mental health in everyday life. While many studies show daily activity improves mood, the effects of daily light exposure on mood remain unknown. This study evaluated the effects of daily natural light exposure and activity on daily mood and evaluate whether depression moderate effects. METHODS/STUDY POPULATION: 82 adults with lifetime major depression disorder (25 current) and 49 healthy controls were recruited from the greater Chicago community (N = 131, 62% female, age M = 30.15, SD = 9.94). At baseline, participants completed the Inventory of Depression and Anxiety Symptoms to measure depression symptoms of anhedonia, or loss of pleasure. Positive and negative affect were then measured 3x daily for 14-days via self-report using smartphones while light exposure and activity were continuously recorded from a wrist-worn actigraphy device. Following prior studies, daily natural light exposure was measured as the total number of white light samples greater than 1000 lux each day. Multilevel models were used to separate within-person (daily level) from between-person (subject level) effects. RESULTS/ANTICIPATED RESULTS: Results revealed daily within-person activity (p &lt; .001) and natural light exposure duration (p = .035) were independently associated with increased positive affect. Effects were significantly moderated by baseline anhedonia symptoms (3-way interaction: p = .004). Natural light exposure duration only increased positive affect on lower activity days for high anhedonia and higher activity days for low anhedonia (ps &lt; .018). Significant results remained controlling for between-person light and activity, time of year, age, sex, negative affect, and baseline general depression symptoms. Compared to one’s own daily averages, daily activity and natural light exposure may be independent pathways to boost positive affect, especially for individuals with high anhedonia symptoms. DISCUSSION/SIGNIFICANCE: Results suggest daily natural light exposure may be an accessible, low-cost alternative to independently increase positive affect in depression on days when activity is low. Translational applications are discussed focusing on transdiagnostic implications for physical and mental health conditions that disrupt mood and limit activity.

Modelling photoperiod in enhancing hydrogen production from Chlorella vulgaris sp. while bioremediating ammonium and organic pollutants in municipal wastewater

Municipal wastewater is ubiquitously laden with myriad pollutants discharged primarily from a combination of domestic and industrial activities. These heterogeneous pollutants are threating the natural environments when the traditional activated sludge system fails sporadically to reduce the pollutants' toxicities. Besides, the activated sludge system is very energy intensive, bringing conundrums for decarbonization. This research endeavoured to employ Chlorella vulgaris sp. In converting pollutants from municipal wastewater into hydrogen via alternate light and dark fermentative process. The microalgae in attached form onto 1 cm3 of polyurethane foam cubes were adopted in optimizing light intensity and photoperiod during the light exposure duration. The highest hydrogen production was recorded at 52 mL amidst the synergistic light intensity and photoperiod of 200 μmolm−2s−1 and 12:12 h (light:dark h), respectively. At this lighting condition, the removals of chemical oxygen demand (COD) and ammoniacal nitrogen were both achieved at about 80%. The sustainability of microalgal fermentative performances was verified in recyclability study using similar immobilization support material. There were negligible diminishments of hydrogen production as well as both COD and ammoniacal nitrogen removals after five cycles, heralding inconsequential microalgal cells’ washout from the polyurethane support when replacing the municipal wastewater medium at each cycle. The collected dataset was finally modelled into enhanced Monod equation aided by Python software tool of machine learning. The derived model was capable to predict the performances of microalgae to execute the fermentative process in producing hydrogen while subsisting municipal wastewater at arbitrary photoperiod. The enhanced model had a best fitting of R2 of 0.9857 as validated using an independent dataset. Concisely, the outcomes had contributed towards the advancement of municipal wastewater treatment via microalgal fermentative process in producing green hydrogen as a clean energy source to decarbonize the wastewater treatment facilities.