Effect Of Light Irradiation Research Articles

Effect of UV light irradiation, pH and concentration on the dye sequestration efficiency of anionic surfactant based self-assembled aqueous mesophases

Lyotropic lamellar phases are prepared by using the varying concentration of sodium dodecyl sulfate: water (SDS: W) and then doped with methyl blue dye (0.01 wt.%). Textural analysis confirms that the addition of the dye does not perturb the lamellar patterns. Dye molecules may self-assembled over the lamellar aqueous interface in an ordered fashion. Lyotropic lamellar phases are explored for methyl blue sequestration/adsorption under the influence of UV irradiation (125 W and λ=365 nm). No structural phase change in lyotropic systems has been observed after UV irradiation. However, visual blue to colourless transition and continuous suppression of adsorption intensity has been seen for the dye-doped system. About 97–99% sequestration efficiency is noted for these lyotropic systems within 60 min in alkaline pH (8–9). Sequestration/ adsorption of dye could be the result of electrostatic interactions amidst N+ and O− of dye and anionic surfactant SDS. Such interactions alter one of the double bonds of one NH group of methyl blue permanently, hence, disrupts the molecular planarity of the dye molecule and could be a cause of dye sequestration. The effect of varying pH has also been discussed. Studied systems could be seen as an economic and efficient adsorbent for water and impurity purification applications.

Effect of NIR light on the permeability of the blood-brain barriers in in vitro models.

The blood-brain barrier (BBB) is a dynamic barrier between the blood microcirculation system and the brain parenchyma, which plays an important role in the pathogenesis of a variety of neurological diseases. Meanwhile, a non-invasive therapeutic approach of photobiomodulation (PBM) has emerged as a promising treatment for neurological disorders through irradiation with near infrared (NIR) light. However, despite multiple encouraging results reported for PBM in vitro and in vivo, the mechanisms of its therapeutic effect on brain, especially on the BBB, remain barely known. Herein, the effect of NIR light irradiation on the in vitro BBB models was studied. 808 nm laser irradiation at the doses of 10 and 30 J/cm2 was found to significantly increase the permeability of this BBB model. The results showed that NIR light affected mitochondria of cells in the in vitro BBB models, leading to an increase in the mitochondrial activity, reactive oxygen species (ROS) level and Ca2+ influx. The activity of matrix metalloproteinases and the expression of the tight junction proteins in the endothelial cells were found to be inhibited by the NIR light, resulting in an increase in the BBB permeability. This study suggested a new strategy for drug transport across the BBB in development of treatments for brain disorders.

Effects of UV light irradiation on fluctuation enhanced gas sensing by carbon nanotube networks

The exceptionally large active surface-to-volume ratio of carbon nanotubes makes it an appealing candidate for gas sensing applications. Here, we studied the DC and low-frequency noise characteristics of a randomly oriented network of carbon nanotubes under NO2 gas atmosphere at two different wavelengths of the UV light-emitting diodes. The UV irradiation allowed to sense lower concentrations of NO2 (at least 1 ppm) compared to dark conditions. Our experimental studies confirmed that the flicker noise of resistance fluctuations under UV irradiation significantly enhanced the sensing characteristics of nanotube networks at low concentrations. We observed a dominating 1/f-like noise component below 1 kHz. The sensitivity of nanotube networks was higher for shorter wavelength, whereas drift in the resistance was smaller for longer wavelength. The measurements under the NO2 gas atmosphere revealed a remarkable reduction in DC resistance drift of the nanotube network between consecutive cycles of gas sensing. This phenomenon was explained via absorption-desorption of NO2 gas molecules on nanotubes surface. Since small concentrations of NO2 pose a threat to the ecosystem, these results might play a significant role in the development of sensitive nanotubes-based photo-activated gas sensors.

Interdental Plaque Microbial Community Changes under In Vitro Violet LED Irradiation.

Oral microbiome dysbiosis has important links to human health and disease. Although photodynamic therapy influences microbiome diversity, the specific effect of violet light irradiation remains largely unknown. In this study, we analyzed the effect of violet light-emitting diode (LED) irradiation on interdental plaque microbiota. Interdental plaque was collected from 12 human subjects, exposed to violet LED irradiation, and cultured in a specialized growth medium. Next-generation sequencing of the 16S ribosomal RNA genes revealed that α-diversity decreased, whereas β-diversity exhibited a continuous change with violet LED irradiation doses. In addition, we identified several operational taxonomic units that exhibited significant shifts during violet LED irradiation. Specifically, violet LED irradiation led to a significant reduction in the relative abundance of Fusobacterium species, but a significant increase in several species of oral bacteria, such as Veillonella and Campylobacter. Our study provides an overview of oral plaque microbiota changes under violet LED irradiation, and highlights the potential of this method for adjusting the balance of the oral microbiome without inducing antibiotic resistance.

Effects of light irradiation on the textural properties and energy metabolism of postharvest shiitake mushrooms ( Lentinula edodes )

Shiitake mushrooms (Lentinula edodes) easily get deteriorated along with softening during the storage. And energy dissipation is associated with senescence and deterioration of many agro-products. In this study, the evident effect of light irradiation on the softening and the energy dissipation mechanism of shiitake mushrooms (L. edodes) during storage was investigated. Postharvest shiitake mushrooms were treated with light irradiation of 2,300–2,800 lux, and stored at 10°C and 90% RH for 18 days. Textural properties, reactive oxygen species (ROS) level, antioxidant activity, antioxidase activity, malondialdehyde (MDA) content, electrolyte leakage, energy status, enzyme activities, total phenolic content, and genes expressions related to energy metabolism were determined. Results indicated that compared with non-irradiation, qualities of shiitake mushrooms treated with light irradiation were better maintained until 18 days of storage. Light irradiation exerted better effects on maintaining the textural properties of shiitake mushrooms, led to the lower ROS level and cell membrane peroxidation. Moreover, a higher energy status was detected with light irradiation, which could be attributed to the enhanced enzyme activities (H+-ATPase, Ca2+-ATPase, SDH, and CCO activities) and relative gene expressions. Novelty impact statement Light irradiation in the range of 2,300–2,800 lux applied on fresh shiitake mushrooms during the storage, exerted effect on texture properties maintenance, led to the low levels of MDA content, electrolyte leakage, and antioxidant activities. Meanwhile, higher energy status and enhanced enzyme activities as well as relative gene expressions were detected in light-irradiated mushrooms. This study provides a potential application of light irradiation in maintaining the shelf life and storage quality of postharvest shiitake mushrooms, as well as a perspective on correlation between textual quality and energy metabolism.

Effect of far-red and blue light irradiation on nutritional quality in postharvest cherry tomato

Effect of far-red and blue light irradiation on nutritional quality in postharvest cherry tomato

Effect of light irradiation on heightened adsorption of dyes by hydrothermal carbon microspheres

Monodisperse carbon microspheres (CMSs) with various diameters were prepared from glucose under controllable hydrothermal conditions at mild temperature. The as-synthesized CMSs were mainly characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and Raman spectrometer. Their adsorption capacity was evaluated by the measurements of relative concentrations of methyl orange (MO), Rhodamine B (RhB) and methylene blue (MB) in the solution under UV and/or visible light irradiation, respectively. By UV and/or visible light irradiation after the saturation of adsorption in the dark, a marked decrease in concentration of RhB and MB was observed, which recovered a heightened adsorption capacity of CMSs. With the decrease of dye concentration, the relative removal of dye increased. Moreover, the diameter of CMSs affected the irradiation-heightened adsorption, which the smaller ones improved the enhancement. The adsorption capacities of the studied CMSs for MB and RhB are estimated to be from 12.08 mg g−1 in the dark to 24.28 mg g−1 after irradiation and from 6.83 mg g−1 in the dark to 21.47 mg g−1 after irradiation, respectively. The adsorption kinetics obeys pseudo-first-order kinetics following the Freundlich isotherm. A possible mechanism for the irradiation-heightened adsorption property of CMSs was discussed.

Coherence control of directional nonlinear photocurrent in spatially symmetric systems

The interplay between crystal symmetry and its optical responses is at the heart of tremendous recent advances in light-matter interactions and applications. Nonlinear optical processes that produce electric currents, for example the bulk photovoltaic (BPV) effect, require inversion-symmetry-broken materials, such as ferroelectrics. In this work, we demonstrate that such BPV current could be generated in centrosymmetric materials with excitation of out-of-equilibrium coherent phonons. This is very different from the generally studied static or thermally excited states. We show that depending on the coherent phonon phase factor, the photoconductivity contains a static zero-frequency component, as well as THz frequency components. This indicates that a unidirectional current may emerge under synergistic effects of atomic vibration and light irradiation. We also generalize the conventional injection charge current into angular momentum (spin and orbital) degrees of freedom, and demonstrate spin and orbital BPV photoconductivities under coherent phonons. Our findings open the pathway to exploring the exotic phonon-photon-electron coherent interactions in quantum materials.

Effect of Light Irradiation on the Diffusion Rate of the Charge Carrier Hopping Mechanism in P3HT–ZnO Nanoparticles Studied by μ+SR

Blended regio-regular P3HT–ZnO nanoparticles are a hybrid material developed as an active layer for hybrid solar cells. The study of the hopping mechanisms and diffusion rates of regio-regular P3HT–ZnO nanoparticles is significant for obtaining intrinsic charge transport properties that provide helpful information for preparing high-performance solar cells. The temperature dependences of the parallel and perpendicular diffusion rates in regio-regular P3HT–ZnO nanoparticles determined from muon spin relaxation measurements were investigated by applying various longitudinal fields. We investigated the effect of light irradiation on the diffusion rates in regio-regular P3HT–ZnO nanoparticles. We found that with increasing temperature, the parallel diffusion rate decreased, while the perpendicular diffusion rate increased. The ratio of the parallel to perpendicular diffusion rate (D‖/D⊥) can be used to indicate the dominant charge carrier hopping mechanism. Without light irradiation, perpendicular diffusion dominates the charge carrier hopping, starting at 25 K, with a ratio of 1.70×104, whereas with light irradiation, the perpendicular diffusion of the charge carrier starts to dominate at the temperature of 10 K, with a ratio of 2.40×104. It is indicated that the additional energy from light irradiation affects the diffusion, especially the charge diffusion in the perpendicular direction.

Evaluation of Photobiogoverning Role of Blue Light Irradiation on Viral Replication.

Most recently, severe acute respiratory syndrome coronavirus-2 has triggered a global pandemic without successful therapeutics. The goal of the present study was to define the antiviral effect and therapeutic action of blue light irradiation in SARS-CoV-2-infected cells. Vero cells were infected with SARS-CoV-2 (NCCP43326) or mock inoculum at 50 pfu/well. After blue light irradiation, the inhibitory effect was assessed by qPCR and plaque reduction assay. When Vero cells were irradiated to blue light ranging from 1.6 to 10 J cm-2 , SARS-CoV-2 replication was inhibited by up to 80%. The antiviral effect of blue light irradiation was associated with translation suppression via the phosphorylation of eIF2α by prolonging endoplasmic reticulum (ER) stress. The levels of LC3A/B and Beclin-1, which are key markers of autophagy, and the levels of PERK and PDI for ER stress were highly increased, whereas caspase-3 cleavage was inhibited after blue light irradiation in the later stage of infection. Our data revealed that blue light irradiation exerted antiviral and photo-biogoverning activities by prolonging ER stress and stimulating autophagy progression during viral infection. The findings increase our understanding of how photo-energy acts on viral progression and have implications for use in therapeutic strategies against COVID-19.

Methylammonium halide-doped perovskite artificial synapse for light-assisted environmental perception and learning

Optoelectronic synapses that integrate and process light and electric signals simultaneously received giant attention for the development of artificial visual system. However, to mimic robust perception and processing ability of biological vision demands exceptional photoresponse and tunable plasticity of the optoelectronic synaptic units. Herein, we demonstrated a Methylammonium (MA) halide-doped perovskite artificial synapse. The introduction of MA halide additives into formamidinium lead iodide (FAPbI3) can effectively improve the film morphology and crystallinity, leading to a wider regulatory range of synaptic plasticity. The effect of light irradiation on shaping synaptic plasticity was revealed to realize important synaptic functions. With the assistance of light stimuli, high-order learning behaviors have been achieved, including dynamic logic operation and conditioned reflex. A higher pattern recognition accuracy (88.2%) of handwritten digits was achieved in simulation. Moreover, the correlation between light irradiation and the hybrid perovskite-based artificial synapse can be utilized to perceive environmental change and to tune information processing efficiency. These results provide a new strategy for constructing future artificial intelligent system.

Clinical Effect of Blue Light Irradiation Combined with Early Touch in the Treatment of Neonatal Jaundice

Clinical Effect of Blue Light Irradiation Combined with Early Touch in the Treatment of Neonatal Jaundice

Exogenous cortisol and red light irradiation affect reproductive parameters in the goldfish Carassius auratus.

Reproductive hormones play essential roles in the control of reproduction and gonadal maturation in fish. The purpose of this study was to determine the effects of cortisol administration (10 µg/g or 50 µg/g) or red light irradiation at two intensities (0.5 W/m2 or 1.0 W/m2) on the reproductive hormones in goldfish (Carassius auratus). The effects of different treatments were analyzed by determining the mRNA expression levels of gonadotropin-inhibitory hormone receptor (GnIH-R), chicken gonadotropin-releasing hormone (cGnRH-II), salmon GnRH (sGnRH), FSHβ, LHβ, and plasma testosterone and the level of 17β-estradiol for 48 h. Additionally, by double immunofluorescence staining, we detected the expression of both GnIH and GnRH in the diencephalons of goldfish brains. The mRNA expression of GnIH-R was significantly higher in the cortisol group and red light-irradiated group from 3 to 48 h than in the control group. Additionally, the mRNA levels of cGnRH-II, sGnRH, FSHβ, LHβ, testosterone, and 17β-estradiol were significantly lower in the cortisol group than in the other groups from 3 to 48 h. These results indicated that both cortisol and red light-emitting diode (LED) light increased GnIH expression and inhibited GnRH expression. In particular, red light irradiation suppressed reproductive responses as much as the cortisol treatment at 48 h. Thus, it could be an alternative method for suppressing reproductive responses in future aquacultures.

The influence of selective light on the growth reaction and antioxidant system of seedlings Pisum sativum L.

Aim. Study of the effect of red (660 nm), green (530 nm) and blue (450 nm) light on the growth processes and the state of the antioxidant system in the axial organs of seedlings of pea plants. Methods. Etiolated seedlings of pea Maecenat variety were irradiated with selective light with different spectrum of RL (660 nm), GL (530 nm), BL (450 nm) to activate photoreceptor systems of plants. In 10-day-old seedlings, growth response was determined – linear growth and biomass accumulation, as well as indicators of antioxidant system – hydrogen peroxide content and activity of oxidases – catalase and nonspecific peroxidase in axial organs of seedlings: in the aboveground part and roots. Results. Irradiation of the RL and the GL stimulates the accumulation of seedling biomass in the aboveground part and roots. BL inhibits the growth response of seedlings. The maximum stimulating effect is shown by the GL. The state of the antioxidant system in etiolated seedlings is characterized by organ specificity. Under the action of selective light, the content of the main form of ROS – hydrogen peroxide and shoots and in the roots, significantly stimulates the activity of catalase and peroxidase enzymes in the aboveground part of the seedling and is inhibited in the roots. The maximum effect in the aboveground part is shown by the GL, in the roots of the RL and the BL. Conclusions. The established effects of selective light irradiation are manifested differently in the aboveground and underground parts of seedlings. Possible mechanisms of connection of a condition of antioxidant system with separate aspects of signaling in photomorphogenesis of plants are discussed.
 Keywords: Pisum sativum L., selective light, RL (660 nm), GL (530 nm), BL (450 nm), growth reaction, axial organs, H2O2, catalase, peroxidase.

Possible Routes to Obtain Enhanced Magnetoresistance in a Driven Quantum Heterostructure with a Quasi-Periodic Spacer.

In this work, we perform a numerical study of magnetoresistance in a one-dimensional quantum heterostructure, where the change in electrical resistance is measured between parallel and antiparallel configurations of magnetic layers. This layered structure also incorporates a non-magnetic spacer, subjected to quasi-periodic potentials, which is centrally clamped between two ferromagnetic layers. The efficiency of the magnetoresistance is further tuned by injecting unpolarized light on top of the two sided magnetic layers. Modulating the characteristic properties of different layers, the value of magnetoresistance can be enhanced significantly. The site energies of the spacer is modified through the well-known Aubry–André and Harper (AAH) potential, and the hopping parameter of magnetic layers is renormalized due to light irradiation. We describe the Hamiltonian of the layered structure within a tight-binding (TB) framework and investigate the transport properties through this nanojunction following Green’s function formalism. The Floquet–Bloch (FB) anstaz within the minimal coupling scheme is introduced to incorporate the effect of light irradiation in TB Hamiltonian. Several interesting features of magnetotransport properties are represented considering the interplay between cosine modulated site energies of the central region and the hopping integral of the magnetic regions that are subjected to light irradiation. Finally, the effect of temperature on magnetoresistance is also investigated to make the model more realistic and suitable for device designing. Our analysis is purely a numerical one, and it leads to some fundamental prescriptions of obtaining enhanced magnetoresistance in multilayered systems.

Effect of combination of light and drought stress on physiology and oxidative metabolism of rice plants

The realized productivity of crop plants is generally lower than the potential productivity due to the influence of one or more external stresses (biotic and abiotic). Simultaneous occurrence of combination of abiotic stresses, which is more common under field condition, results in compounded effect on functional processes. Main focus of the present work is the combined effect of drought and light (irradiance) on rice plants. Potted seedlings of four selected rice lines (viz., IR36, N22, CRD40 and Bhootmuri) were exposed to three different levels of drought stress (50%, 25%, 12.5% of water) along with control (100%) in combination with three different light intensities (high, medium and low) during experimental period. After 7 days of stress, plant height and relative water content (RWC) were relatively low while root length increased with increasing water stress level and light intensity. Protein content increased with increasing water stress and light intensity, while chlorophyll level was higher at higher light intensities. Malondialdehyde (MDA) content, indicative of lipid peroxidation, increased with water stress only at high light intensities. Superoxide dismutase (SOD), peroxidase (POX) and ascorbate peroxidase (APX) activities increased with combined drought and light stress level, whereas catalase (CAT) activity was higher at higher light intensities. On the other hand, superoxide (O2.-) production, but not hydrogen peroxide (H2O2) production was higher with increasing water stress and light intensity. It appears that light-induced ROS (O2.-) production under drought condition provoked oxidative stress, though a potential mechanism of tolerance was apparent through antioxidant system.

Influence of light-irradiated Noccaea caerulescens on the characteristics of dissolved organic matter in its rhizospheric soil during phytoremediation.

It has been observed that suitable light irradiation can improve the phytoremediation efficiency of various plants by enhancing their growth rate and metal uptake capacity. However, the mechanisms underlying the effects of light irradiation on metal mobilization and translocation in soils have rarely been reported. This experiment was conducted to evaluate the variation in dissolved organic matter (DOM) in the rhizosphere of Noccaea caerulescens (formerly Thlaspi caerulescens J. & C. Presl) when irradiated with different combinations of red (0, 25, 50, 90, and 100% red) and blue light. N. caerulescens was induced to secrete significantly more DOM, relative to the control, into its rhizosphere after being irradiated with pure red light and other red light combinations; this increased the bioavailability of soil Cd. Moreover, the concentrations and proportions of the hydrophilic DOM fractions, particularly hydrophilic acid, which exhibited a high affinity for Cd, increased with increasing ratios of the red light. Furthermore, DOM secreted because of the light irradiation treatments exhibited a significantly higher Cd extraction ability compared with that of the untreated control; this consequently increased the Cd uptake capacity of N. caerulescens. The results demonstrated that the secretion of more DOM, particularly hydrophilic acid, plays a pivotal role in improving the phytoremediation efficiency of N. caerulescens.

Design and synthesis of BiVO4@CuOx as a photo assisted Fenton-like catalyst for efficient degradation of tetracycline

The rational design and fabrication of stable and efficient heterogeneous Fenton-like catalyst is of great significance for wastewater treatment, but is also fraught with obstacles. In this paper, we synthesized BiVO4@CuOx composite catalyst through a simple hydrothermal method and in situ chemical deposition. The degradation of tetracycline (TC) is carried out as a main model pollutant through Fenton reaction assisted by light irradiation. The prepared catalyst exhibits superb efficiency and satisfactory stability for the degradation of TC owing to the synergistic effect of light irradiation and decomposition of H2O2. The factors influencing the degradation such as catalyst dosage, H2O2 concentration and initial pH value are also investigated. Moreover, a possible mechanism of degradation of TC in BiVO4@CuOx/H2O2 system is discussed based on the premise that •OH, •O2− and h+ are demonstrated to be the main active species via in-situ ESR measurements. This work puts forward a new suggestion for designing and synthesizing photo assisted Fenton-like catalyst to remove organic contaminants in sewage.

Performance Analysis of Various Advanced Oxidation Processes on COD Removal from Raw Petroleum Refinery Effluent

Objectives : This comparative study investigated various methods of advanced oxidation processes (AOPs) that were separately conducted for treating raw petroleum refinery effluent regarding chemical oxygen demand (COD) removal.Methods : Fenton, photo-Fenton, TiO2, ZnO, TiO2/Ultra violet (UV), and ZnO/UV were performed individually for measuring the effect of light irradiation, treatment time, pH, catalysts dosage, and light source on the profile of COD values.Results and Discussion : The experimental data of this work showed that the dependency on the light exposure in heterogeneous photo-catalytic reaction using TiO2 and ZnO is higher than that of homogeneous photo-Fenton technique. The optimum operating conditions in heterogeneous system occurred at 100 min of oxidation time, pH 5, and catalyst dosage 1 g/L that resulted in 21.8, 20.68, 60.9, and 55.17% of COD removal for TiO2, ZnO, TiO2/UV, and ZnO/UV, respectively. In contrast, both Fenton and photo-Fenton experienced their highest performance at pH 4 by obtaining 44.2 and 59.77% of COD removal, respectively. Eventually, kinetic study indicated that COD degradation can be well expressed by second-order pattern that reached higher correlation coefficient values by 0.999 and 0.998 for TiO2/UV and TiO2, respectively.Conclusions : Overall, it could be assumed that AOPs are reliable techniques to purify raw and complex raw industrial effluents.

Illuminating the effect of beneficial blue light and ROS-modulating enzymes in Dupuytren's disease.

Dupuytren's disease (DD) is a fibroproliferative disorder of the palmar aponeurosis, which is characterized by a compound myofibrogenesis and evidenced by an increased expression of α-smooth muscle actin (α-SMA). In Dupuytren's tissue, higher levels of reactive oxygen species (ROS) are documented, stimulating the proliferation and differentiation of myofibroblasts. Our preliminary study demonstrates that α-SMA-expression is significantly inhibited by blue light irradiation in DD. The objective of this study was to investigate the beneficial effect of blue light irradiation and to elucidate the influence of ROS on myofibrogenesis in the pathogenesis of DD. Therefore, an in-vitro model of human DD fibroblasts was used. DD fibroblasts and control fibroblasts isolated from carpal tunnel syndrome (CTS) were daily irradiated with 40 J/cm2 (λ = 453 nm, 38 mW/cm2). Protein expression of ROS-modulating enzymes (Catalase, NOX4, SOD1, MnSOD) and α-SMA were determined, and additionally analysed after a pharmacological inhibition of the TGF-β1-signaling with SB431542. Furthermore, the protein expression of α-SMA as surrogate parameter for myofibrogenesis was evaluated after applying different concentrations of long-lasting ROS. It could be determined that the beneficial blue light irradiation, which inhibited myofibrogenesis, is mediated by a significant inhibition of catalase protein expression. This effect should be accompanied with an increased intracellular ROS level. Proof of evidence was an H2O2-application on DD fibroblasts, also leading to a decreased myofibrogenesis. Furthermore, it could be demonstrated that endogenous MnSOD was significantly downregulated in resting DD fibroblasts. If DD fibroblasts were treated with the pharmacological inhibitor SB431542, myofibrogenesis was inhibited, but MnSOD expression was simultaneously elevated, which ought to affect ROS level by raising intracellular H2O2 amount. Blue light irradiation as well as the pharmacological action of SB431542 in consequence mediates their beneficial effect on disturbed myofibrogenesis in DD by further increasing ROS level. The present study demonstrates the importance of intracellular ROS homeostasis in DD and illuminates the beneficial effect of blue light as a promising therapy option for DD.