High-intensity Light Source Research Articles

Intense pulsed light therapy for ocular surface diseases.

Intense pulsed light (IPL) is a non-laser, high-intensity light source that has been shown to play a valuable role in dermatology and has been adopted in ophthalmology for treating meibomian gland dysfunction (MGD). In this review, we discuss the mechanism of action of IPL, including its benefits in ophthalmology. IPL therapy has been shown to improve tear film stability, meibomian gland (MG) function, and subjective symptoms of ocular dryness in MGD patients. Moreover, emerging evidence suggests that IPL therapy is beneficial for other ocular surface diseases, such as blepharitis and chalazia. Hence, it can be inferred that IPL has potential as a therapeutic modality in future applications. Large clinical and experimental trials are needed to exploit the full potential of IPL as a treatment for recurrent chalazia, Sjögren's syndrome, and other causes of dry eye disease (DED). This paper reviews the published literature related to the application of IPL for treating ocular surface diseases.

Zeaxanthin epoxidase 3 Knockout Mutants of the Model Diatom Phaeodactylum tricornutum Enable Commercial Production of the Bioactive Carotenoid Diatoxanthin.

Carotenoids are pigments that have a range of functions in human health. The carotenoid diatoxanthin is suggested to have antioxidant, anti-inflammatory and chemo-preventive properties. Diatoxanthin is only produced by a few groups of microalgae, where it functions in photoprotection. Its large-scale production in microalgae is currently not feasible. In fact, rapid conversion into the inactive pigment diadinoxanthin is triggered when cells are removed from a high-intensity light source, which is the case during large-scale harvesting of microalgae biomass. Zeaxanthin epoxidase (ZEP) 2 and/or ZEP3 have been suggested to be responsible for the back-conversion of high-light accumulated diatoxanthin to diadinoxanthin in low-light in diatoms. Using CRISPR/Cas9 gene editing technology, we knocked out the ZEP2 and ZEP3 genes in the marine diatom Phaeodactylum tricornutum to investigate their role in the diadinoxanthin-diatoxanthin cycle and determine if one of the mutant strains could function as a diatoxanthin production line. Light-shift experiments proved that ZEP3 encodes the enzyme converting diatoxanthin to diadinoxanthin in low light. Loss of ZEP3 caused the high-light-accumulated diatoxanthin to be stable for several hours after the cultures had been returned to low light, suggesting that zep3 mutant strains could be suitable as commercial production lines of diatoxanthin.

Nonreciprocal propagation of optical pulses in a one-dimensional photonic crystal with two Weyl semimetal-based defects

We investigated the nonreciprocal propagation properties of an optical pulse in a one-dimensional photonic crystal containing Weyl semimetal-based defect layers. High optical nonreciprocity, without the need for high-intensity input light sources or external magnetic fields, is the most essential property of the Weyl semimetal. The transfer matrix and Fourier transform techniques are used to obtain the time envelopes of the transmitted pulses. It is demonstrated that the transmitted pulse may attain two different time envelopes by reversing the impinging direction of the input pulse. Then, the effects of the input pulse carrier frequency and time width on the characteristics of the transmitted pulse are presented and shown that reversing the impinging direction of the input pulse has a significant effect on the length and energy of the transmitted pulse. The results may have applications in designing pulse-shaping filters and transferring digital data.

Design, implementation and performance assessment of a low-cost dual-axis solar tracker

As the demand for energy increases and the cost of non-renewable resources continues to rise, many nations are working to find alternative sources of electricity before a crisis arises. This effort is focused on transitioning away from conventional energy sources and towards non-conventional ones. Energy from the sun is clean and available in natural quantities, which can reduce our dependence on fossil fuels on a large scale along with providing low-carbon solutions. By tracking the sun’s radiations, the photovoltaic (PV) panels could be directed in such a way that they collect high levels of sunlight. This article presents the design and performance assessment of a low-cost dual-axis solar tracking system based on Arduino. The main objective of this study is to show that the proposed solar-tracking system performs better a non-tracking system. A light sensor and two servo motors are also employed to move the solar panel toward a high-intensity light source. The software domain code was created using the C programming language using the Arduino IDE, which interacts with the Arduino board and its other connected devices. The performance of the prototype was assessed and compared to that of a stationary solar panel of the same rating. In this paper, the authors have highlighted the necessary techniques to build a low-cost solar tracker for extracting maximum photovoltaic energy using real-time data. In terms of power output, the results reveal that the tracking system surpasses the fixed solar panel, indicating increased performance at a reasonable cost. Therefore, the solar tracker has been proven to be very effective in capturing significant solar energy for solar harvesting applications.

Surface Defect Detection of Preform Based on Improved YOLOv5

This paper proposes a lightweight detection model based on machine vision, YOLOv5-GC, to improve the efficiency and accuracy of detecting and classifying surface defects in preforming materials. During this process, clear images of the entire surface are difficult to obtain due to the stickiness, high reflectivity, and black resin of the thermosetting plain woven prepreg. To address this challenge, we built a machine vision platform equipped with a linescan camera and high-intensity linear light source that captures surface images of the material during the preforming process. To solve the problem of defect detection in the case of extremely small and imbalanced samples, we adopt a transfer learning approach based on the YOLOv5 neural network for defect recognition and introduce a coordinate attention and Ghost Bottleneck module to improve recognition accuracy and speed. Experimental results demonstrate that the proposed approach achieves rapid and high-precision identification of surface defects in preforming materials, outperforming other state-of-the-art methods. This work provides a promising solution for surface defect detection in preforming materials, contributing to the improvement of composite material quality.

Generation of 13.9-mJ Terahertz Radiation from Lithium Niobate Materials.

Extremely strong-field terahertz (THz) radiation in free space has compelling applications in nonequilibrium condensed matter state regulation, all-optical THz electron acceleration and manipulation, THz biological effects, etc. However, these practical applications are constrained by the absence of high-intensity, high-efficiency, high-beam-quality, and stable solid-state THz light sources. Here, the generation of single-cycle 13.9-mJ extreme THz pulses from cryogenically cooled lithium niobate crystals and a 1.2% energy conversion efficiency from 800nm to THz are demonstrated experimentally using the tilted pulse-front technique driven by a home-built 30-fs, 1.2-Joule Ti:sapphire laser amplifier. The focused peak electric field strength is estimated to be 7.5MVcm-1 . A record of 1.1-mJ THz single-pulse energy at a 450 mJ pump at room temperature is produced and observed that the self-phase modulation of the optical pump can induce THz saturation behavior from the crystals in the substantially nonlinear pump regime. This study lays the foundation for the generation of sub-Joule THz radiation from lithium niobate crystals and will inspire more innovations in extreme THz science and applications.

An Approach to Developing Cyanines with Upconverted Photosensitive Efficiency Enhancement for Highly Efficient NIR Tumor Phototheranostics.

Upconverted reactive oxygen species (ROS) photosensitization with one-photon excitation mode is a promising tactic to elongate the excitation wavelengths of photosensitive dyes to near-infrared (NIR) light region without the requirement of coherent high-intensity light sources. However, the photosensitization efficiencies are still finite by the unilateral improvement of excited-state intersystem crossing (ISC) via heavy-atom-effect, since the upconverted efficiency also plays a decisive role in upconverted photosensitization. Herein, a NIR light initiated one-photon upconversion heavy-atom-free small molecule system is reported. The meso-rotatable anthracene in pentamethine cyanine (Cy5) is demonstrated to enrich the populations in high vibrational-rotational energy levels and subsequently improve the hot-band absorption (HBA) efficiency. Moreover, the spin-orbit charge transfer intersystem crossing (SOCT-ISC) caused by electron donated anthracene can further amplify the triplet yield. Benefiting from the above two aspects, the 1 O2 generation significantly increases with over 2-fold improved performance compared with heavy-atom-modified method under upconverted light excitation, which obtains efficient in vivo phototheranostic results and provides new opportunities for other applications such as photocatalysis and fine chemical synthesis.

A Review on Modeling Cure Kinetics and Mechanisms of Photopolymerization.

Photopolymerizations, in which the initiation of a chemical-physical reaction occurs by the exposure of photosensitive monomers to a high-intensity light source, have become a well-accepted technology for manufacturing polymers. Providing significant advantages over thermal-initiated polymerizations, including fast and controllable reaction rates, as well as spatial and temporal control over the formation of material, this technology has found a large variety of industrial applications. The reaction mechanisms and kinetics are quite complex as the system moves quickly from a liquid monomer mixture to a solid polymer. Therefore, the study of curing kinetics is of utmost importance for industrial applications, providing both the understanding of the process development and the improvement of the quality of parts manufactured via photopolymerization. Consequently, this review aims at presenting the materials and curing chemistry of such ultrafast crosslinking polymerization reactions as well as the research efforts on theoretical models to reproduce cure kinetics and mechanisms for free-radical and cationic photopolymerizations including diffusion-controlled phenomena and oxygen inhibition reactions in free-radical systems.

High Intensity Violet Light (405 nm) Inactivates Coronaviruses in Phosphate Buffered Saline (PBS) and on Surfaces

It has been proven that visible light with a wavelength of about 405 nm exhibits an antimicrobial effect on bacteria and fungi if the irradiation doses are high enough. Hence, the question arises as to whether this violet light would also be suitable to inactivate SARS-CoV-2 coronaviruses. Therefore, a high-intensity light source was developed and applied to irradiate bovine coronaviruses (BCoV), which are employed as SARS-CoV-2 surrogates for safety reasons. Irradiation is performed in virus solutions diluted with phosphate buffered saline and on steel surfaces. Significant virus reduction by several log levels was observed both in the liquid and on the surface within half an hour with average log reduction doses of 57.5 and 96 J/cm2, respectively. Therefore, it can be concluded that 405 nm irradiation has an antiviral effect on coronaviruses, but special attention should be paid to the presence of photosensitizers in the virus environment in future experiments. Technically, visible violet radiation is therefore suitable for coronavirus reduction, but the required radiation doses are difficult to achieve rapidly.

ОПРОМІНЕННЯ ОВОЧІВ В УМОВАХ ЗАКРИТОГО ҐРУНТУ ДЖЕРЕЛАМИ СВІТЛА З ВИПРОМІНЮЮЧИМИ ДОБАВКАМИ

Purpose. The paper considers peculiarities of using artificial illumination sources with effective spectral composition of radiation for conditions of closed soil. Methodology. High-intensity sodium lamps (DNaT400), high- intensity sources with composition of sodium amalgam with cesium additives were investigated (Hg-20%, Na-7 5%, Cs-5%), potassium (Hg-20%, Na-79%, K-1%). Results. As a result of experiments, it was determined that the spectral radiation composition of lamps with additives Cs, K, Rb has a lower radiation intensity compared to standard high pressure sodium lamps (DNaT) in the region of 500-600 nm and significantly higher intensity in red (600-700 nm) and near infrared regions. The physicochemical properties of the sodium-cesium-mercury system have been studied. Melting points of ternary alloys, thermodynamic properties of melts of ternary system Na-Cs-Hg and double system of Na-Hg system are determined. The parameters of batch pressures of component vapors are calculated. The composition of the discharge tube amalgam is selected, in which the ratio of sodium and mercury concentrations is close to the corresponding ratio in a standard sodium lamp, and cesium additives vary in the range from 5 to 10 atm. %. The influence of cesium content in amalgams on light and color parameters of lamps is considered. Tomatoes were used in the experiment, which were additionally illuminated with lamps DNaT400, high intensity discharge tube filled light sources (20at.% Hg, 77at.% Na, 3at.% Cs20); (20at.% Hg, 75at.% Na, 5at. % Cs); (20 at. % Hg, 73 at. % Na, 7 at. % Cs); (20 at. % Hg, 70 at. % Na, 10 at. % Cs). Originality. In the use of high-pressure sodium lamps with a filling of the discharge tube in different weight ratios of Hg, Na, Cs. Practical value. When using high-intensity light sources with additives Cs having amalgam composition (20 at.% Hg, 75 at.% Na, 5 at.% Cs), growing tomato plants in the early stages of development is most effective. The total content of chlorophyll in tomatoes when irradiated with a high- pressure sodium lamp with cesium additives is 1.4 ÷ 2.5 times higher than when irradiated. DNaT400.

History of prospecting and development of deposits of quartz raw materials in the Urals and the prospect of their further use

Relevance of the work. For 60 years of hard work of quartz workers in the geological industry, Soviet geologists have fully provided the USSR industry for many years to come with piezoquartz and high-grade, highly pure quartz for the production of all types of quartz products. Much has changed over the years; and it became necessary to analyze the existing raw material base of Russia for quartz for smelting. Purpose of the work: analysis of the existing raw material base of Russia for quartz raw materials and the role of the deposits of quartz raw materials in the Ural region in solving this problem. Research methodology. The history of the use of quartz material as an industrial raw material and its application by the most developed countries of Europe is briefly outlined. It is shown that in the presence of various genetic types of quartz in the territory of Russia, the main deposits of highly pure quartz are located within the Ural region. The history of the complex and multiple reorganization of geological units that carried out prospecting, exploration, production and processing of all types of quartz raw materials from the Urals deposits is considered in detail. With the aim of centralization of exploration, mining operations, the production of industrial products from quartz and gemstones, scientific and project construction works in the Urals, the production association Uralkvartssamotsvety has been established since November 1, 1977. In terms of its technological equipment, the level of technology and organization of production, the achieved technical and economic indicators and allocations, the Uralkvartszamotsvety association was the flagship among the related associations of the USSR Ministry of Geology. Conclusions. Nowadays, the severe issue of the raw material base of quartz in Russia is the provision of the domestic industry with raw materials for the fusion of special transparent quartz glasses used primarily in microelectronics, fiber optics, and the production of high-intensity light sources. Ural had been and could continue to be the main supplier of raw materials and especially pure quartz. The reserves of these types of raw materials are significant, and the deposits are located in favorable economic and geographical areas.

Near-Infrared Light and Skin: Why Intensity Matters.

Infrared light (760 nm-1 mm) constitutes approximately 40% of the solar radiation reaching the ground at sea level. Shortest wavelength near-infrared (NIR) photons (NIR or IR-A: 760-1,400 nm) can penetrate the epidermis, dermis, and subcutaneous tissue with numerous biological effects. NIR used to have a bad reputation on the basis of past studies using high-intensity artificial light sources (above the solar IR-A irradiance threshold) at high doses leading to detrimental effects (i.e., upregulation of matrix metalloproteinase-1). However, when looking at the other side of the coin and what we can learn from the sun, NIR intensity matters. Hence, mimicking sunlight NIR intensity (30-35 mW/cm2) will rather trigger beneficial cutaneous effects. It is likely that intensity is more important than the fluence (dose) delivered. Moreover, the law of reciprocity (i.e., the biological effect is directly proportional to the total dose irrespective of intensity) does not always apply when considering tissue response in photobiology. In fact, the biphasic dose curve (Arndt-Schulz curve) of photobiomodulation establishes that if irradiance is lower than the physiological threshold value for a given target, it does not produce beneficial effects, even when -irradiation duration is extended. Also, photo-inhibitory deleterious effects may occur at higher irradiances. Remarkably, the beneficial "sweet spot" in between corresponds to the irradiance of the sun. NIR might even precondition the skin from an evolutionary standpoint as exposure to early morning NIR wavelengths in sunlight may prepare the skin for upcoming mid-day harmful UVR. Consequently, NIR light appears to be the solution, not the problem.

Unexpected photosensitivity of the well-characterized heme enzyme chlorite dismutase

Chlorite dismutase is a heme enzyme that catalyzes the conversion of the toxic compound ClO2− (chlorite) to innocuous Cl− and O2. The reaction is a very rare case of enzymatic O–O bond formation, which has sparked the interest to elucidate the reaction mechanism using pre-steady-state kinetics. During stopped-flow experiments, spectroscopic and structural changes of the enzyme were observed in the absence of a substrate in the time range from milliseconds to minutes. These effects are a consequence of illumination with UV–visible light during the stopped-flow experiment. The changes in the UV–visible spectrum in the initial 200 s of the reaction indicate a possible involvement of a ferric superoxide/ferrous oxo or ferric hydroxide intermediate during the photochemical inactivation. Observed EPR spectral changes after 30 min reaction time indicate the loss of the heme and release of iron during the process. During prolonged illumination, the oligomeric state of the enzyme changes from homo-pentameric to monomeric with subsequent protein precipitation. Understanding the effects of UV–visible light illumination induced changes of chlorite dismutase will help us to understand the nature and mechanism of photosensitivity of heme enzymes in general. Furthermore, previously reported stopped-flow data of chlorite dismutase and potentially other heme enzymes will need to be re-evaluated in the context of the photosensitivity.Graphic abstractIllumination of recombinantly expressed Azospira oryzae Chlorite dismutase (AoCld) with a high-intensity light source, common in stopped-flow equipment, results in disruption of the bond between FeIII and the axial histidine. This leads to the enzyme losing its heme cofactor and changing its oligomeric state as shown by spectroscopic changes and loss of activity.

A self-monitoring precision calibration light source for large-volume neutrino telescopes

With the rise of neutrino astronomy using large-volume detector arrays, calibration improvements of optical media and photosensors have emerged as significant means to reduce detector systematics. To improve understanding of the detector volume and its instrumentation, we developed an absolutely-calibrated, self-monitoring, isotropic, nanosecond, high-intensity calibration light source called “Precision Optical Calibration Module” (POCAM). This, now third iteration, of the instrument was developed for an application in the IceCube Upgrade but, with a modular instrument communications and synchronization backend, can provide a calibration light source standard for any large-volume photodetector array. This work summarizes the functional principle of the POCAM and all related device characteristics as well as its precision calibration procedure. The latter provides fingerprint-characterized instruments with knowledge on absolute and relative behavior of the emitted light pulses as well as their temperature dependencies.

Rapid Detection Device of Methamphetamine Based on Improved Light Emitting Diode Induced Fluorescence Detector

In recent years, drug abuse has become a major public health problem, drug-driving poses serious threats to the public security. For the urgent need to rapidly on-site screen drug evidence and drug abusers, we have developed a fluorescent drug detection device based on LED induction (FD-LED). The core part of the device is 365 nm high-intensity LED excitation light source, FD-LED detector' performance was tested by the fluorescent brightener OB. In this study, the FD-LED detector was evaluated, and the influence of baseline noise, baseline drift, sensitivity, detection limit and quantitative limit on the detector was analyzed, the result showed that the proposed detector had good stability and sensitivity, at the same time, the chromatographic detection conditions were set, the solution based on methamphetamine C1 sample was collocated, and combined with liquid chromatography, a detection system for methamphetamine was developed. The results showed that the minimum detection amount of the sample was 1.0 × 10–9 g/ml, and the signal-concentration relationship was obvious in the range of 1.0 ng/ml∼15.6 ng/ml. This device could provide an effective method for roadside drug testing and clinical diagnosis, and give helpful assistance to law enforcement officers.

Use of Intense Pulsed Light to Mitigate Meibomian Gland Dysfunction for Dry Eye Disease.

Dry Eye Disease (DED) is a common ocular condition that needs prompt diagnosis and careful treatment interventions. If left untreated, it can lead to numerous sight-threatening complications, including ulceration of the cornea, blepharitis, alterations of the tear film, conjunctivitis, and in severe cases, may lead to scarring, thinning, and even perforation of the cornea. Intense pulsed light (IPL) is a non-laser high-intensity light source that has shown to play a valuable role in dry eye disease. Recent evidence from various research works has shown that IPL modifies the mechanism of meibomian gland dysfunction (MGD), which helps to relieve the symptoms of DED. In this review, we demonstrated the mechanism of action of IPL, including its benefits on DED. The emerging evidence shows that the role of IPL in DED is novel and therapeutic. These results direct us to conclude that IPL is a potentially beneficial tool and essential future therapy for dry eye disease. Advances in the treatment of DED will lead to a better quality of life. However, tools to recognize potentially severe side effects of DED earlier in order to treat or prevent them must be developed.

Compartmentalized Jet Polymerization as a High-Resolution Process to Continuously Produce Anisometric Microgel Rods with Adjustable Size and Stiffness.

In the past decade, anisometric rod-shaped microgels have attracted growing interest in the materials-design and tissue-engineering communities. Rod-shaped microgels exhibit outstanding potential as versatile building blocks for 3D hydrogels, where they introduce macroscopic anisometry, porosity, or functionality for structural guidance in biomaterials. Various fabrication methods have been established to produce such shape-controlled elements. However, continuous high-throughput production of rod-shaped microgels with simultaneous control over stiffness, size, and aspect ratio still presents a major challenge. A novel microfluidic setup is presented for the continuous production of rod-shaped microgels from microfluidic plug flow and jets. This system overcomes the current limitations of established production methods for rod-shaped microgels. Here, an on-chip gelation setup enables fabrication of soft microgel rods with high aspect ratios, tunable stiffness, and diameters significantly smaller than the channel diameter. This is realized by exposing jets of a microgel precursor to a high intensity light source, operated at specific pulse sequences and frequencies to induce ultra-fast photopolymerization, while a change in flow rates or pulse duration enables variation of the aspect ratio. The microgels can assemble into 3D structures and function as support for cell culture and tissue engineering.

Electroluminescence of Single InGaN/GaN Micropyramids

The results of the fabrication of technological regimes of formation and the study of the optical properties of light emitting diodes (LED) micropyramids based on InGaN/GaN are presented. The structures were formed by the method of Metalorganic vapour-phase epitaxy. LED hetero structures based on single micropyramids demonstrate electroluminescence at a wavelength of 520–590 nm, which is shifted to the shortwave length region with increasing current pumping. These light-emission sources are of interest for the fabrication of high-intensity point light sources for biosensor applications.

Электролюминесценция одиночных InGaN/GaN микропирамид

AbstractThe results of the fabrication of technological regimes of formation and the study of the optical properties of light emitting diodes (LED) micropyramids based on InGaN/GaN are presented. The structures were formed by the method of Metalorganic vapour-phase epitaxy. LED hetero structures based on single micropyramids demonstrate electroluminescence at a wavelength of 520–590 nm, which is shifted to the shortwave length region with increasing current pumping. These light-emission sources are of interest for the fabrication of high-intensity point light sources for biosensor applications.

Simulation of color afterimages: An approach to computing virtual color perception

Afterimages are a common and frequent perceptual phenomenon of everyday life. When looking into a high-intensity light source and suddenly turning away from it, a temporary ``ghost'' of the light source remains visible, for a while. The computer-graphics simulation of afterimages is based on biophysical and mathematical models as published in the literature. A subordinate of afterimages defined in our research is virtual color perception, that is in our interpretation an unusual and intense temporary color perception provoked by a rapid change in the color of the incident light. In research, the modelling of virtual color perception is a field that is by and large untouched. Our publication presents a kinetic model established to characterize the intensity and duration of virtual color perception as a function of rapid changes in the color of the incident light.