Visible White Light Research Articles

Carbon quantum dots of Moringa oleifera with bactericidal action

In this work, carbon quantum dots (CQDs) were synthesized using a hydrothermal reactor. The precursor for the CQDs was Moringa oleifera seed oil, extracted using a 1:8 ethanol-to-mass ratio through ultrasound-assisted extraction (50 ºC, 30 min). The extract was then purified using a rotary evaporator (50 ºC, 50 rpm) to remove the solvent, followed by centrifugation (12,000 rpm, 10 min). Subsequently, the oil was transferred to a Teflon-lined capsule within a stainless-steel reactor and heated in a muffle furnace (210 ºC, 24 h). The synthesized CQDs were then centrifuged (12,000 rpm, 10 min) and filtered through a 0.22 μm membrane. These CQDs exhibited high fluorescence and, when activated photodynamically with white visible light, showed the ability to inhibit the growth of the Gram-positive bacterium Staphylococcus aureus, a common cause of skin infections. In recent decades, the inappropriate use of antibiotics has led to increased bacterial resistance, resulting in higher mortality rates in humans and animals. Therefore, the development of nanomaterials with antimicrobial properties, through a simple, cost-effective, and sustainable route, is essential for public health and safety.

Highlighter: An optogenetic system for high-resolution gene expression control in plants.

Optogenetic actuators have revolutionized the resolution at which biological processes can be controlled. In plants, deployment of optogenetics is challenging due to the need for these light-responsive systems to function in the context of horticultural light environments. Furthermore, many available optogenetic actuators are based on plant photoreceptors that might crosstalk with endogenous signaling processes, while others depend on exogenously supplied cofactors. To overcome such challenges, we have developed Highlighter, a synthetic, light-gated gene expression system tailored for in planta function. Highlighter is based on the photoswitchable CcaS-CcaR system from cyanobacteria and is repurposed for plants as a fully genetically encoded system. Analysis of a re-engineered CcaS in Escherichia coli demonstrated green/red photoswitching with phytochromobilin, a chromophore endogenous to plants, but also revealed a blue light response likely derived from a flavin-binding LOV-like domain. We deployed Highlighter in transiently transformed Nicotiana benthamiana for optogenetic control of fluorescent protein expression. Using light to guide differential fluorescent protein expression in nuclei of neighboring cells, we demonstrate unprecedented spatiotemporal control of target gene expression. We implemented the system to demonstrate optogenetic control over plant immunity and pigment production through modulation of the spectral composition of broadband visible (white) light. Highlighter is a step forward for optogenetics in plants and a technology for high-resolution gene induction that will advance fundamental plant biology and provide new opportunities for crop improvement.

Facile Microwave Synthesis of Efficient Green Emissive Carbon Dots Powder and Their Application in Visible Light Communication and White Light Emitting Devices

AbstractHighly green emissive solid‐state carbon dots (CDs) with photoluminescence quantum efficiency of 58% are prepared through a rapid microwave assisted heating method. Due to the spatial confinement from the biuret crystal matrix, aggregation among CDs is effectively suppressed, thus allowing the CDs to give efficient emission in the solid‐state. The CDs show excitation independent emission and mono‐exponential decay characteristics with a nearly constant lifetime of ≈13 ns upon varying the detected emissions, indicating the presence of a single type of emissive state in the CDs. Due to their high quantum efficiency and short lifetime, the obtained CDs are applied as the color conversion layer of a near‐ultraviolet micro light‐emitting diode (µLED) chip (405 nm) for visible light communication, achieving a modulation bandwidth of 165 MHz, which is much higher than the bandwidth of the conventional combination of Ce3+‐doped yttrium aluminum garnet phosphor with GaN LED. Moreover, the green emitting solid‐state CDs are applied to fabricate a prototype white LED device, which exhibits good lighting suitability with a color rendering index of 90.6 and a Commission Internationale de L'Eclairage chromaticity coordinates of (0.327, 0.332).

Solar Energy Storage Using a Cu2 O-TiO2 Photocathode in a Lithium Battery.

A Cu2 O-TiO2 photoelectrode is pr+oposed for simultaneous solar light energy harvesting and storing of electrochemical energy in an adapted lithium coin cell. The p-type Cu2 O semiconductor layer is the light harvester component of the photoelectrode and the TiO2 film performs as the capacitive layer. The rationale of the energy scheme shows that the photocharges generated in the Cu2 O semiconductor induce lithiation/delithiation processes in the TiO2 film as a function of the applied bias voltage and light power. A photorechargeable lithium button cell drilled on one side recharges with visible white light in ≈9h in open circuit. It provides an energy density of ≈150mAhg-1 at 0.1C discharge current in dark, and the overall efficiency is 0.29%. This work draws a new approach for the photoelectrode role to advance in monolithic rechargeable batteries.

A lightweight network of near cotton‐coloured impurity detection method in raw cotton based on weighted feature fusion

AbstractThe objective is to improve the recognition rate of white and near cotton‐coloured impurities in raw cotton against a single white visible light source background. A lightweight detection network model without anchor boxes based on improved YOLO v4‐tiny is proposed in this paper based on weighted feature fusion (WFF). The WFF strategy was used to improve the detection accuracy of the improved YOLO v4‐tiny algorithm. Meanwhile, to address the disadvantage that the anchor boxes obtained by the K‐means algorithm clustering do not have global features, the anchor‐free and tiny decoupled head schemes are used instead of the traditional coupled detection head. The improved algorithm was validated on the PASCAL VOC2012 dataset and the self‐built raw cotton impurity dataset collected by high‐speed camera. On the raw cotton impurity test set, compared to the original YOLO v4‐tiny model, the mean average precision (mAP) and frames per second (FPS) of the improved model increased by 10.35% and 6.9%, respectively. The proposed model detects white and near cotton‐coloured impurities with an accuracy of up to 98.78% and 98.00%. The experimental results show that the proposed method can effectively detect and identify impurities in raw cotton, which is of great practical significance for foreign matter detection and identification in cotton.

RP-HPTLC fingerprinting of secondary metabolites from Nephrolepis exaltata and Cycasrevoluta

This study aims to develop a quantitative fingerprinting between two evolutionary close plant species Nephrolepis exaltata (L.) Schott and Cycas revoluta Thunb. The crude plant extracts were prepared in 1:1:1, v/v/v: Ethyl Acetate: n-Hexane: Methanol (AR) solvent system through cold extraction for 24 Hrs. The plant extracts were diluted (10 mg/mL) with a similar solvent system spotted (10 μL) on silica gel 60 F254 thin-layer chromatography plates. Five mobile phases (i) tetrahydrofuran (THF): toluene: formic acid: water (16:8:2:1) (ii) toluene: ethyl acetate: diethylamine (7:2:1) (iii) toluene: ethyl acetate: formic acid (7:3:0.1) (iv) n-hexane: ethyl acetate (7.2:2.9) (v) toluene: methanol (9:1) were used. The results were scanned at 254 nm, 366 nm, and in visible white light. This study gave minimum compact spots between Rf 0.06 to 0.051 corresponding to terpenoids, simultaneously for flavonoids spots were found between Rf 0.004 to 0.910. Total eight phenolic bands were found in Cycas revoluta among which five was found in leaf extract with Max RF of 0.033, 0.093, 0.273, 0.901 and 0.964 whereas three bands were found in stem extract with Max Rf of 0.007, 0.897 and 0.954. The presence of fifteen different types of flavonoids was determined by the flavonoids profile at Rf 0.004, 0.027, 0.047, 0.073, 0.134, 0.230, 0.303, 0.369, 0.369, 0.427, 0.514, 0.631, 0.703, 0.757, 0.846 and 0.910 for Nephrolepis exaltata. HPTLC fingerprint has shown several peaks with different Rf for different mobile phases. The fingerprinting would be helpful in the identification, and authentication of these species ecologically and therapeutically.

High-sensitivity fluorescence-detected multidimensional electronic spectroscopy through continuous pump-probe delay scan.

Fluorescence-detected multidimensional electronic spectroscopy (fMES) promises high sensitivity compared to conventional approaches and is an emerging spectroscopic approach toward combining the advantages of MES with the spatial resolution of a microscope. Here, we present a visible white light continuum-based fMES spectrometer and systematically explore the sensitivity enhancement expected from fluorescence detection. As a demonstration of sensitivity, we report room temperature two-dimensional coherence maps of vibrational quantum coherences in a laser dye at optical densities of ∼2-3 orders of magnitude lower than conventional approaches. This high sensitivity is enabled by a combination of biased sampling along the optical coherence time axes and a rapid scan of the pump-probe waiting time T at each sample. A combination of this approach with acousto-optic phase modulation and phase-sensitive lock-in detection enables measurements of room temperature vibrational wavepackets even at the lowest ODs. Alternative faster data collection schemes, which are enabled by the flexibility of choosing a non-uniform undersampled grid in the continuous T scanning approach, are also demonstrated.

Explosion Differentiation Using Light Emissions—Nuclear Reactor, Steam, Water Hammer, Hydrogen, Piper Alpha, and Hydro-Volcanic Explosions

Abstract Light emissions during chemical reactions provide insights into various scenarios to better understand explosions and water hammers. For example, hydrogen burning and explosions emit blue light, organic carbon combustion and explosions emit combinations of blue and yellow light, water phase changes emit infrared and less visible white light, and white light explosions ignite when multiple chemical reactions are involved. Since experimental tests to observe infrared light during water hammers have not yet been performed, test data from water boiling tests and volcanoes are compared to larger water hammer and steam explosion incidents. Considering these facts and examining a series of photos and videos from the literature and Internet, determinations are proven with respect to water hammers, steam explosions, Piper Alpha water hammer explosions, and chemical explosions. Such evidence proves that steam explosions are important for water hammer accidents, but chemical explosions explain other explosions that have long been considered to be steam explosions. These other explosions include nuclear power plant explosions, hydro-volcanic explosions, and hydrogen explosions, where some of these explosions are, in fact, related to water hammers. This article is primarily a photographic essay to explain the differences between different types of explosions and water hammers, although combustion and explosion principles are expanded and explained to support this essay.

Construction of Hexagonal Prism-like Defective BiOCL Hierarchitecture for Photocatalytic Degradation of Tetracycline Hydrochloride.

Oxygen vacancy manipulation and hierarchical morphology construction in oxygen-containing semiconductors have been demonstrated to be effective strategies for developing high efficiency photocatalysts. In most studies of bismuth-based photocatalysts, hierarchical morphology and crystal defects are achieved separately, so the catalysts are not able to benefit from both features. Herein, using boiling ethylene glycol as the treatment solution, we developed an etching-recrystallization method for the fabrication of 3D hierarchical defective BiOCl at ambient pressure. The target hierarchical 3D-BiOCl is composed of self-assembled BiOCl nanosheets, which exhibit a hexagonal prism-like morphology on a micron scale, while simultaneously containing numerous oxygen vacancies within the crystal structure. Consequently, the target catalyst was endowed with a higher specific surface area, greater light harvesting capability, as well as more efficient separation and transfer of photo-excited charges than pristine BiOCl. As a result, 3D-BiOCl presented an impressive photocatalytic activity for the degradation of tetracycline hydrochloride in both visible light and natural white light emitting diode (LED) irradiation. Moreover, an extraordinary recycling property was demonstrated for the target photocatalyst thanks to its hierarchical structure. This study outlines a simple and energy-efficient approach for producing high-performance hierarchically defective BiOCl, which may also open up new possibilities for the morphological and crystal structural defect regulation of other Bi-based photocatalysts.

Two-Photon Vision in Age-Related Macular Degeneration: A Translational Study.

The recently introduced term “two-photon vision” relates to the visual perception resulting from a simultaneous absorption of two photons by photoreceptors. In this study, we determined two-photon retinal sensitivity in age-related macular degeneration (AMD) and compared it that in normal aging. Microperimetry was performed with visible (white) light and infrared (IR) light, which was perceived as green in the two-photon stimulation. In total, 45 subjects were included with one (better) eye studied. Furthermore, best-corrected visual acuity (VA) and ocular straylight were assessed. AMD resulted in decreased median (interquartile range) logMAR VA, i.e., 0.15 (0.05; 0.24), which in normal eyes was −0.02 (−0.06; 0.02). The two groups showed comparable straylight levels. Sensitivity to IR light was significantly lower in the AMD group (p < 0.001): 8.3 (7.4, 9.3) dB than in controls 10.7 (9.7, 11.2) dB. AMD also significantly affected visible light sensitivity (p < 0.001): 14.0 (11.0; 15.5) dB vs. 18.0 (16.3; 18.9) dB. Notably, the two-photon approach yielded a lower data spread. In conclusion, AMD considerably impairs retinal sensitivity measured in the single- and two-photon realm. However, two-photon-vision microperimetry may improve the testing accuracy and offer an additional diagnostic parameter (beyond VA measurements) for retinal function assessment.

Lotus Seedpod Proanthocyanidins Protect Against Light-Induced Retinal Damage via Antioxidative Stress, Anti-Apoptosis, and Neuroprotective Effects.

BackgroundOver-exposure to visible white light can cause retinal damage. Lotus seedpod proanthocyanidins (LSPCs) possess a variety of biological activities, including potent antioxidant and protective effects. Herein, this study observed whether LSPCs can protect against light exposure-induced retinal damage.Material/MethodsWe randomly separated 40 Prague-Dawley rats into a control group, a light exposure-induced retinal injury model group, and low-dose (50 mg/kg), medium-dose (100 mg/kg), and high-dose (100 mg/kg) LSPCs groups. Light-induced retinal damage models were established by 5000±200 Lx light treatment for 6 h. Five days and 0.5 h before the light treatment, rats in the LSPCs groups were separately administered 50, 100, and 200 mg/kg LSPCs by gavage. After 7 days, H&E staining of retinal sections was performed and the thickness of the ONL was measured. Oxidative stress-related markers and antioxidant enzymes were measured in serum by biochemical testing. TUNEL staining of retinal sections was also performed. Apoptosis-relevant proteins were examined by RT-qPCR and western blotting. GFAP expression was examined with immunohistochemistry.ResultsOur H&E staining showed that LSPCs can prevent retinal degeneration following light exposure. Histological analysis showed a significant reduction in the ONL thickness of light exposure-induced retinal injury rats, but LSPCs substantially improved the ONL thickness. LSPCs markedly ameliorated the light-induced increase in levels of MDA, NO, and NOS, and decrease in activity of GSH-Px and SOD. Moreover, LSPCs treatment alleviated light-induced retinal apoptosis and limited the light-induced increase in GFAP expression.ConclusionsLSPCs effectively attenuated light-induced retinal damage through antioxidative stress, anti-apoptosis, and neuroprotective effects.

Hybrid Genetic Programming and Multiverse-based Optimization of Pre-Harvest Growth Factors of Aquaponic Lettuce Based on Chlorophyll Concentration

<p class='IJASEITAbtract'>Optimizing photosynthesis is vital in maintaining quality farm produce in the agricultural food production sector. The nonlinear behavior of the interaction of crop pre-harvest growth factors can promote or retard its growth. This study employed multigene symbolic regression genetic programming (MSRGP) in developing the chlorophyll-<em>a</em> fitness function allied with bioinspired algorithms, namely genetic algorithm (GA), particle swarm optimization (PSO), and multiverse optimization (MVO), in determining the ideal combination of carbon dioxide, light intensity, air temperature, and humidity that will induce photosynthesis based on aquaponic lettuce (<em>Lactuca sativa var. Altima</em>) leaf chlorophyll-<em>a </em>concentration. Light spectra were characterized through the floating leaf disk technique, which resulted in white spectra as the most photosynthetic conducive based on the light reaction and dark respiration. Leaf spectro-textural-morphological signatures were extracted for non-destructive MSRGP chlorophyll-<em>a</em> concentration measurement. Carbon dioxide and humidity have a strong positive impact on chlorophyll-<em>a </em>concentration. Photosynthesis is impeded by Vis/IR above 7.817. The hybrid MSRGP-MVO generated the ideal global solution of 880.744 ppm of CO₂, 543.147 μmol m^-2 s^-1 of the visible white light spectrum, 22.238 °C air temperature, and 67.742% humidity which resulted in 651.144 mg g^-1 of Chl-<em>a</em>, 0.934 leaf weight ratio, 0.066 roots to shoot ratio, 141 xylem vessels mm^-2 127.389 stomata mm^-2, and more prominent intracellular chloroplast concentration for the harvest stage lettuce. The established standard for fresh weight, chlorophylls <em>a</em> and <em>b</em>, and vitamin C concentrations are essential for developing an adaptive nutrient management system to maintain the expected growth signatures of lettuce at the end of the 6-week cultivation cycle.

Highly photocatalytic active r-GO/Fe3O4 nanocomposites development for enhanced photocatalysis application: A facile low-cost preparation and characterization

This research explores reduced graphene oxide-Fe3O4 nanocomposites synthesis, characterization, and it's ability to degrade methylene blue dye using sodium lamp as the visible white light source. The modified co-precipitation method was employed for the synthesis of the photocatalyst. The photocatalyst was further characterized by various characterization techniques. Moreover, photocatalytic activity was performed by varying performance conditions, and analyzed the results. It was found that photocatalyst has highly active performance at the working conditions of pH 12 with 50 mg catalyst for 10 ppm methylene blue dye solutions and produced 98.3% degradation of the dye within 80 min. It was also observed that minor positive performance was observed on varying temperature and catalyst concentration. The photocatalytic activity was found highly dependent on the pH of the solution and increased with an increase in pH. Additional studies were also performed by adding some amount of hydrogen peroxide in the solution without changing its pH. It was also noted that as the amount of hydrogen peroxide was increased in the solution, there was an increment in the degradation of the dye. A maximum of 98.8% degradation was recorded with the 9 ml addition of hydrogen peroxide-containing 25 mg catalyst, pH 8, and at 40 °C reaction temperature within 70 min of irradiation.

Up‐conversion phosphor plate for white lighting device using NIR excitation source

AbstractUpconversion phosphors have numerous advantages compared to down conversion phosphor materials, such as a weak background interface, low excitation energy, sharp emission lines, and long lifetimes. Conventionally, blue laser diodes are used to obtain strong white light by combining green‐ and red‐emitting phosphors. The blue‐excited white‐light‐emitting devices can be harmful when the blue light penetrates directly into the human body. However, lower energy excited lighting devices does not harm the human body because of their low‐energy photons are compatible with the biologically safe window. Hence, we present a prototype device that converts invisible near‐infrared light into visible white light. For this, we synthesized orange‐emitting Y2O3:Er3+, Yb3+ and blue‐emitting Y2O3:Tm3+, Yb3+ upconversion phosphors using a solid‐state reaction. Using these, phosphor‐in‐glass (PiG) samples with sintered glass frit were prepared to investigate their optical behavior under low‐excitation energy. The emission color from the stacked PiGs depends on the color balance between the activator ions of Er3+, Tm3+, and Yb3+, and their balance is optimized to obtain a white light. The results might pave the way for designing safe white‐light‐emitting devices using a low‐energy excitation source.

Insight into the Chemistry of PETN Under Shock Compression Through Ultrafast Broadband Mid-Infrared Absorption Spectroscopy.

Thin films of pentaerythritol tetranitrate (PETN) were shock compressed using the laser driven shock apparatus at Los Alamos National Laboratory (LANL). Two spectroscopic probes were available to this apparatus: visible white light transient absorption spectroscopy (VIS) from 400 to 700 nm and mid-infrared transient absorption spectroscopy (MIR) from 1150 to 3800 cm-1. Important PETN vibrational modes are the symmetric and antisymmetric NO2 stretches at 1280 and 1650 cm-1, respectively, as well as CH stretches at ∼2900 cm-1. Shock strength was varied from approximately 3 to 55 GPa to span from the chemically unreactive regime to the regime in which fast chemical reaction took place on the 250 ps time scale of the measurements. VIS and MIR results suggest irreversible chemistry was induced in PETN at pressures above 30 GPa. At lower shock pressures, the spectroscopy showed minimal changes attributable to pressure induced effects. Under the higher-pressure reactive conditions, the frequency region at the antisymmetric NO2 stretch mode had a significantly increased absorption while the region around the symmetric NO2 stretch did not. No observable increased absorption occurred in the higher frequency regions where CH-, NH-, and OH- bond absorptions would be observed. A broad absorption appeared on the shoulder at the red-edge of the CO2 vibrational band around 2200 cm-1. In addition to the experiments, reactive molecular dynamics were carried out under equivalent shock conditions to correlate the evolution of the infrared spectrum to molecular processes. The simulations show results consistent to experiments up to 30 GPa but suggest that NO and NO2 related features provided the strongest contributions to the shocked infrared changes. Proposed mechanisms for shocked PETN chemistry are analyzed as consistent or inconsistent with the data presented here. Our experimental data suggests C≡O or N2O bond formation, nitrite formation, and absence of significant hydroxyl or amine concentrations in the initial chemistry steps in PETN shocked above 30 GPa.

UV-A in the NICU: New Technology for an Old Challenge

Healthcare-associated infections (HAIs) are a serious concern in the NICU. Alternatives or supplements to manual cleaning are increasingly being explored, including ultraviolet (UV) disinfection technologies. A recently-developed hybrid lighting system technology, designed to provide both visible white light and disinfecting UV-A (λmax = 366 nm) radiation, was retrofitted into a hospital newborn intensive care unit (NICU). The UV-A dosing was set to levels calculated to be safe for continuous adult occupation. The results showed that eight-hour exposures of 3 W m-2 on counter surfaces were effective for suppressing bacteria that commonly cause HAIs in the NICU. Although UV-A is not as effective at inactivating viruses as UV-C, it is safe for use while space is occupied, making it a promising technology for consideration in certain areas of the NICU.

Self-assembled bio-inspired Au/CeO2 nano-composites for visible white LED light irradiated photocatalysis

In this study, plasmonic PDA@Au/CeO2 composites were produced by a self-assembled redox approach. The morphologies, chemical compositions, and optical properties of the composites were investigated. The obtained results showed that the immobilization of Au NPs with good localized surface plasmon resonance (LSPR) properties together with the formation of CeO2(shell)-Au(core) structure onto polydopamine nanoparticles (PDA NPs, as both reducing and stabilizing template) led to the production of active oxygen vacancies between valance and conduction bands as well as enhanced the visible light absorption of the catalyst. The plasmon sensitized photocurrent stability and photoluminescence behaviors clearly revealed the close Schottky contact between CeO2(shell) and Au(core) which led to the decrease in the band gap of composites. Therefore, the study of the photocatalytic mechanism of composites demonstrated that increased ECB value, reduced band gap, great photoresponsivity, plasmon assisted charge separation/transfer properties, and production of active oxygen vacancies provided a new heterogeneous photocatalyst with reasonable good reusability and stability for efficient decolorization of MB under visible LED light irradiation.

Parathyroid glands verification using the auto-fluorescence identification tool

In the clinical cases, one of the methods of intraoperative verification of the parathyroid glands (PTG) by visualization of the autofluorescence is considered. PTG have a unique ability for near-infrared autofluorescence, using endogenous fluorophores that are not yet fully characterized. Intraoperative imaging of PTG autofluorescence is possible using a camera that provides laser excitation of near-infrared light and visible white LED light. Without the introduction of any contrast agent, the spontaneous fluorescence of PTG to near-infrared light allows accurate identification of unchanged PTG in almost all cases. Angiography using ICG fluorescence is performed to patients after thyroidectomy to visualize the blood supply of identified PTGs and assess their viability. In clinical cases, patients were described: 2 with diagnosed with papillary thyroid cancer, 1 with a diagnosis of primary hyperparathyroidism. Adenoma of the lower right PTG. In all cases, the specified method of imaging of the thyroid gland was used, first without contrast agent at the stage of PTG extraction, then with the introduction of indocyanine green solution (ICG) at the final stage of the operation. This greatly improved the imaging of unchanged thyroid glands, the assessment of their viability and the prognosis of possible hypocalcemia in the early postoperative period. This clinical cases suggest that the use of the effect of autofluorescence with intravenous intraoperative administration of iodine-containing contrast agent ICG, enables a clear visualization of the parathyroid glands and the evaluation of the vascular trophism of the latter. This is especially important in cases of total thyroidectomy with extensive neck dissections, since the risk of damage to the thyroid gland, especially when the latter within the thymus, is quite high. In addition, the laboratory tests performed in the postoperative periods peak in favor of the effect of autofluorescence, since it provides data for analysis and prevention of postoperative transient hypocalcaemia.

An assessment of a hybrid lighting system that employs ultraviolet-A for mitigating healthcare-associated infections in a newborn intensive care unit

Reducing healthcare-associated infections is critically important. A new hybrid lighting system technology, designed to provide both visible white light and disinfecting UV-A (λmax = 366 nm) radiation, was retrofitted into a modern hospital newborn intensive care unit. The UV-A dosing was set to levels calculated to be safe for human occupation (maximum of 10 W m−2 for 8 hours at eye level). Eight-hour exposures at 3 W m−2 on newborn intensive care unit counter surfaces were effective for suppressing selected pathogens identified by the Centers for Disease Control and Prevention as problematic for healthcare facilities. Professional staff accepted the hybrid lighting system, although its implementation in this newborn intensive care unit was not completely satisfactory. An analysis of photodegrading effects suggested that UV-A resistant equipment and furnishing may need to be installed with this technology. The present findings should form the foundation for the next generation of this lighting technology.

Color-changing intensified light-emitting multifunctional textiles via digital printing of biobased flavin.

Flavin mononucleotide (biobased flavin), widely known as FMN, possesses intrinsic fluorescence characteristics. This study presents a sustainable approach for fabricating color-changing intensified light-emitting textiles using the natural compound FMN via digital printing technologies such as inkjet and chromojet. The FMN based ink formulation was prepared at 5 different concentrations using water and glycerol-based systems and printed on cotton duck white (CD), mercerized cotton (MC), and polyester (PET) textile woven samples. After characterizing the printing inks (viscosity and surface tension), the photophysical and physicochemical properties of the printed textiles were investigated using FTIR, UV/visible spectrophotometry, and fluorimetry. Furthermore, photodegradation properties were studied after irradiation under UV (370 nm) and visible (white) light. Two prominent absorption peaks were observed at around 370 nm and 450 nm on K/S spectral curves because of the functionalization of FMN on the textiles via digital printing along with the highest fluorescence intensities obtained for cotton textiles. Before light irradiation, the printed textiles exhibited greenish-yellow fluorescence at 535 nm for excitation at 370 nm. The fluorescence intensity varied as a function of the FMN concentration and the solvent system (water/glycerol). With 0.8 and 1% of FMN, the fluorescence of the printed textiles persisted even after prolonged light irradiation; however, the fluorescence color shifted from greenish-yellow color to turquoise blue then to white, with the fluorescence quantum efficiency values (φ) increasing from 0.1 to a value as high as 1. Photodegradation products of the FMN with varying fluorescence wavelengths and intensities would explain the results. Thus, a color-changing light-emitting fluorescent textile was obtained after prolonged light irradiation of textile samples printed using biobased flavin. Furthermore, multifunctional properties such as antibacterial properties against E. coli were observed only for the printed cotton textile while increased ultraviolet protection was observed for both cotton and polyester printed fabrics for the high concentration of FMN water-based and glycerol-based formulations. The evaluation of fluorescence properties using digital printing techniques aimed to provide more sustainable solutions, both in terms of minimum use of biobased dye and obtaining the maximum yield.