Light Pulses Research Articles

Evaluation of the analgesic effectiveness of pulsed magnetic therapy and light therapy in the treatment of osteoarthritis of the knee joint

Evaluation of the analgesic effectiveness of pulsed magnetic therapy and light therapy in the treatment of osteoarthritis of the knee joint

High-Throughput Roll-to-Roll Processed Large-Area Perovskite Solar Cells Using Rapid Radiation Annealing Technique.

The development of a stable roll-to-roll (R2R) process for flexible large-area perovskite solar cells (PSCs) and modules is a pressing challenge. In this study, we introduced a new R2R PSC manufacturing system that employs a two-step deposition method for coating perovskite and uses intensive pulsed light (IPL) for annealing. This system has successfully fabricated small-sized cells and the first-ever large-sized, R2R-processed flexible modules. A key focus of our work was to accelerate the conversion of PbI2 to perovskite. To this end, we utilized IPL annealing and incorporated additives into the PbI2 layer. With these modifications, the R2R-processed perovskite films achieved a power conversion efficiency (PCE) of 16.87%, representing the highest reported value for R2R two-step processed PSCs. However, these cells exhibited hysteresis in reverse and forward PCE measurements. To address this, we introduced a dual-annealing process consisting of IPL followed by a 2-min thermal heating step. This approach successfully reduced hysteresis, resulting in low-hysteresis, R2R-processed flexible PSCs. Moreover, we fabricated large-scale flexible modules (10 × 10 cm2) with a PCE of 11.25% using the dual-annealing system, marking a significant milestone in this field.

Rapid fabrication of binder free nickel cobalt oxide electrodes with dendritic nanostructure for electrochemical energy storage applications

A rapid and facile technique to synthesize nickel cobalt oxide electrodes by photothermal treatment of mixed organometallic precursor solution is reported. Using short and intense pulses of light from a xenon flash lamp, spray coated films are converted into porous nickel cobalt oxide electrodes with dendritic nanostructure. The electrode films fabricated in a few seconds show excellent energy storage properties as supercapacitor electrodes. Specific capacitance of up to 116 Fg−1 and capacitance retention of up to 75 % were observed in samples with low mass loading. Analysis of the cyclic voltammetry (CV) curves shows that capacitance is the dominating charge storage mechanism in these films. To study the effect of varying the mass loading in electrodes, double and triple layered electrodes were also studied. In films with high mass loading, the specific capacitance of the films decreased but areal capacitance continued to increase. A high areal capacitance of up to 243 mFcm−2 is observed in films with high mass loading. CV curve analysis of high mass loading electrodes further shows that in films with higher mass loading, the charge storage mechanism is a mix of capacitance and diffusion processes. The contribution of diffusion increased with increase in the mass loading of the electrodes. This study sheds light into the mechanism of charge storage in electrodes prepared by large-scale-amenable single step process of photonic curing which could be utilized to fabricate electrodes in industrial scale.

Novel method to study saturation of silicon photomultiplier in scintillation detector

Signal saturation in the Silicon PhotoMultiplier (SiPM) often causes a serious problem in using a detector equipped with SiPMs for scintillator readout. Conventionally, SiPM signal saturation is measured through direct injection of visible light pulses to the SiPM. However, the method works poorly with the scintillation detector because the effects of the time constant of the emission of scintillation light are not included. Here, we present a novel method to measure the precise degree of SiPM signal saturation in scintillation detectors. The key difference from the conventional method is to use UV light pulses, as opposed to visible light ones, to inject and excite scintillation light in the detector. It allows us to directly measure the degree of saturation in situ taking into account all the major effects in the detector, such as the time constant of the scintillation emission. We also develop a new model for SiPM signal saturation and validate it with the measured degree of saturation with the above-mentioned new method.

Addressing the opportunities of non‐thermal food processing technologies in the ASEAN region context

SummaryThis study aims to explore the opportunities offered by non‐thermal food processing technologies, including high‐pressure processing, pulsed electric fields, ultraviolet light, ultrasound, and microwave that could be viable for the agriculture commodities produced in the ASEAN region. The applications of these technologies across various food product categories (from dairy to fruits and vegetables, meat and seafood, beverages, condiments, fermented foods, edible oil, and ready‐to‐eat meals) focusing on microbial inactivation and mass transfer process enhancement, are systematically discussed to highlight their potential to foster the production of safe, nutritious, and fresh‐like quality food products from the region. The adoption of non‐thermal technologies can face several challenges that hinder the integration of these technologies in ASEAN, including high start‐up costs, limited access to stable electricity and clean water, and inconsistencies in food regulations across countries. Information gaps related to the adoption of non‐thermal technologies within the diverse food‐related scenarios in ASEAN were identified and recommendations were given to improve the state of knowledge in the region. Overall, this work offers critical insights for policymakers, industry stakeholders, and researchers to consider inclusion of non‐thermal technologies in food production as strategic approaches and tailored solutions to enhance the competitiveness of regional food products globally.

Effectiveness of broadband pulsed light and anti-inflammatory doses of minocycline in patients with papulopustular acne

Аbstract. Relevance. Over the past decades, laser devices have been regarded as the method of choice in the treatment of a wide range of skin conditions, including acne. This is the reason for the active search for new methods of therapy, adherence to which in patients with acne would be higher. From this point of view, the increase in the efficiency of broadband pulsed light (IPL) in combination with low doses of minocycline has all the prerequisites for inclusion in the therapeutic complex in the treatment of patients with acne. Purpose of the study. To study the efficacy and safety of using a combined method of therapy with broadband pulsed light and low doses of minocycline in patients with papulopustular acne, taking into account the concentration of MMP-1, MMP-2, MMP-3, MMP-9 in blood serum and the DISS index. Material and methods. Under observation were 100 patients (76 women) and (24 men) aged 18 to 45 years with a diagnosis of papulopustular form of acne, moderate severity. All patients, depending on the initial violation of the skin microbiota, were divided into two groups: group 1–50 patients, group 2–50 patients, each group was divided into subgroups depending on the type of therapy: subgroup A — 25 patients, subgroup B — 25 patients. All patients underwent a study of the concentration of MMP-1, MMP-2, MMP-3, MMP-9 in the blood serum. Research results. The results of comparing the levels of MMP-1, 2, 3, 9 and the DISHS index before and after various methods of therapy in patients with papulopustular acne, of moderate severity in subgroups 1B and 2B showed a more significant trend towards a decrease in MMP-1, 2, 3, 9 and the DISHS index relative to subgroups 1A and 2A. Conclusions. Analyzing the results of the study, we can conclude that the use of a combined method of treatment in patients with papulopustular form of acne, of moderate severity, demonstrated greater efficiency in the dynamics of reducing the levels of MMP-1, 2, 3, 9 concentrations, as well as reducing the total index DISH compared with low-dse minocycline and a topical retinoid.

Characterization of Deformational Isomerization Potential and Interconversion Dynamics with Ultrafast X-ray Solution Scattering.

Dimeric complexes composed of d8 square planar metal centers and rigid bridging ligands provide model systems to understand the interplay between attractive dispersion forces and steric strain in order to assist the development of reliable methods to model metal dimer complexes more broadly. [Ir2 (dimen)4]2+ (dimen = para-diisocyanomenthane) presents a unique case study for such phenomena, as distortions of the optimal structure of a ligand with limited conformational flexibility counteract the attractive dispersive forces from the metal and ligand to yield a complex with two ground state deformational isomers. Here, we use ultrafast X-ray solution scattering (XSS) and optical transient absorption spectroscopy (OTAS) to reveal the nature of the equilibrium distribution and the exchange rate between the deformational isomers. The two ground state isomers have spectrally distinct electronic excitations that enable the selective excitation of one isomer or the other using a femtosecond duration pulse of visible light. We then track the dynamics of the nonequilibrium depletion of the electronic ground state population─often termed the ground state hole─with ultrafast XSS and OTAS, revealing a restoration of the ground state equilibrium in 2.3 ps. This combined experimental and theoretical study provides a critical test of various density functional approximations in the description of bridged d8-d8 metal complexes. The results show that density functional theory calculations can reproduce the primary experimental observations if dispersion interactions are added, and a hybrid functional, which includes exact exchange, is used.

Optical fractional solitonic structures to decoupled nonlinear Schrödinger equation arising in dual-core optical fibers

This paper explores a specific class of equations that model the propagation of optical pulses in dual-core optical fibers. The decoupled nonlinear Schrödinger equation with properties of M fractional derivatives is considered as the governing equation. The proposed model consists of group-velocity mismatch and dispersion, nonlinear refractive index and linear coupling coefficient. Different types of solutions, including mixed, dark, singular, bright-dark, bright, complex and combined solitons are extracted by using the integration methods known as fractional modified Sardar subequation method and modified F-expansion method. Optical soliton propagation in optical fibers is currently a subject of great interest due to the multiple prospects for ultrafast signal routing systems and short light pulses in communications. In nonlinear dispersive media, optical solitons are stretched electromagnetic waves that maintain their intensity due to a balance between the effects of dispersion and nonlinearity. Furthermore, hyperbolic, periodic and exponential solutions are generated. A fractional complex transformation is applied to reduce the governing model into the ordinary differential equation and then by the assistance of balance principle the methods are used, depending upon the balance number. Also, we plot the different graphs with the associated parameter values to visualize the solutions behaviours with different parameter values. The findings of this work will help to identify and clarify some novel soliton solutions and it is expected that the solutions obtained will play a vital role in the fields of physics and engineering.

Frequency comb generation via synchronous pumped χ(3) resonator on thin-film lithium niobate

Resonator-based optical frequency comb generation is an enabling technology for a myriad of applications ranging from communications to precision spectroscopy. These frequency combs can be generated in nonlinear resonators driven using either continuous-wave (CW) light, which requires alignment of the pump frequency with the cavity resonance, or pulsed light, which also mandates that the pulse repetition rate and cavity free spectral range (FSR) are carefully matched. Advancements in nanophotonics have ignited interest in chip-scale optical frequency combs. However, realizing pulse-driven on-chip Kerr combs remains challenging, as microresonator cavities have limited tuning range in their FSR and resonance frequency. Here, we take steps to overcome this limitation and demonstrate broadband frequency comb generation using a χ(3) resonator synchronously pumped by a tunable femtosecond pulse generator with on-chip amplitude and phase modulators. Notably, employing pulsed pumping overcomes limitations in Kerr comb generation typically seen in crystalline resonators from stimulated Raman scattering.

Vector Optical Bullets in Dielectric Media: Polarization Structures and Group-Velocity Effects

Theoretical studies on the generation of nondiffracting and nondispersive light pulses and their experimental implementation are one of the renowned problems within electromagnetics. Current technologies enable the creation of short-duration pulses of a few cycles with high power and fluency. An application of these techniques to the field of nondiffracting and nondispersive pulses requires a proper mathematical description of highly focused vector pulses. In this work, we study vector optical bullets in a dielectric medium with different polarization structures: linear, azimuthal, and radial. We report the differences caused by the vector model compared to the scalar model. We analyze effects caused by superluminal, subluminal, or even negative group velocity on the properties of vector optical bullets inside a dielectric material.

Modern and conventional processing technologies and their impact on the quality of different millets.

Millet, the highly sustainable crop for farming and combating hunger, has recently regained a resurgence in popularity as people seek more sustainable and nutrient-dense alternatives. International organizations and research institutions have advocated for increased millet production and consumption by introducing novel technologies and machinery in response to global food security and climate change challenges. This review aims to identify the impact of modern and conventional processing technologies on the quality of different millets. A comprehensive analysis of research reviews reveals that double-stage and tabletop centrifugal dehullers, infrared roasting, pulsed light, ultrasound, high-pressure processing methods, fortification, and encapsulation are optimal for nutrient retention in various millets. Extrusion technology application in millet processing has created a diverse range of value-added products with extended shelf stability. Emphasis is needed to develop robust promotion and distribution channels and establish an export promotion forum involving all stakeholders to promote and diversify millet-based products and technologies.

Optical microcavity formation and ultrafast control using half-cycle attosecond pulses in two- and three-level media

Light induced population difference gratings have numerous applications in modern optics. The conventional approach of creating them by using monochromatic laser radiation makes it virtually impossible to rapidly control their properties. In recent years, there has been active discussion about using ultra-short light pulses to control such gratings. We show the possibility of ultrafast control of population difference structures, such as dynamic microresonators and Bragg-like grating formations, by the collision of extremely short light pulses in a resonant medium. This work focuses on changes in microcavity properties based on the different parameters, such as the atomic density of the medium, the form of the pulses, and whether the medium is two- or three-level.

Exploring the Dynamics of Dark and Singular Solitons in Optical Fibers Using Extended Rational Sinh–Cosh and Sine–Cosine Methods

Exploring the Dynamics of Dark and Singular Solitons in Optical Fibers Using Extended Rational Sinh–Cosh and Sine–Cosine Methods

Electromagnetically induced gratings created by extremely short non-overlapping pulses of light in a three-level resonant medium

In a fixed spectral range, single- and half-cycle electromagnetic pulses have the shortest duration. Half-cycle pulses are promising tools for ultrafast control of quantum systems. Previously, the possibility of using a sequence of single- and half-cycle attosecond pulses to generate and ultrafast control light-induced population difference gratings has been demonstrated. However, such studies have been carried out using different approximations, such as the sudden perturbation theory and the two-level model for the resonant medium. In this paper, based on the numerical solution of constitutive equations for elements of the density matrix and wave equation it is shown that it is possible to generate and control population gratings in a three-level medium without using the approximation of sudden perturbations used in previous studies. It is shown that taking into account the additional level of the medium does not lead to a violation of the effect of generating such gratings. This extends the applicability of previous results.

Electron Imaging of Nanoscale Charge Distributions Induced by Femtosecond Light Pulses.

Surface charging is ubiquitously observable during in situ transmission electron microscopy of nonconducting specimens as a result of electron beam/sample interactions or optical stimuli and often limits the achievable image stability and spatial or spectral resolution. Here, we report on the electron-optical imaging of surface charging on a nanostructured surface following femtosecond multiphoton photoemission. By quantitatively extracting the light-induced electrostatic potential and studying the charging dynamics on relevant time scales, we gain insights into the details of the multiphoton photoemission process in the presence of an electrostatic background field. We study the interaction of the charge distribution with the high-energy electron beam and secondary electrons and propose a simple model to describe the interplay of electron- and light-induced processes. In addition, we demonstrate how to mitigate sample charging by simultaneously optically illuminating the sample.

A multi-omics study revealed the effect of pulsed light treatment on germinated brown rice: Promotion of sprouting efficiency and gamma-aminobutyric acid enrichment

Physical fields are increasingly proposed in the production of germinated grain foods, thus shorting the preparation cycle of high value-added sprouted grain foods. Here, pulsed light treatment (PLT) with 300 times at a single energy of 400 J was found to significantly promote the shoot length and gamma-aminobutyric acid (GABA) content in 8 varieties of germinated brown rice (GBR). Functional annotation analysis showed that the brown rice germination was promoted by the biosynthesis of phenylalanine, carbohydrate metabolism, and energy metabolism pathway. Moreover, PLT influenced the genes and metabolites involved in the GABA shunt and the polyamine degradation pathway, promoting the accumulation of GABA. Transcription factor OsbZIP56 was closely related to the transcript level of regulatory gene for germination and GABA enrichment. Furthermore, overexpression of OsbZIP56 in rice significantly promoted germination and GABA accumulation. These findings would be significant for improving the germination efficiency of edible seeds, promoting accumulation of active ingredients, and exploring gene functions in food materials.

Bragg-like microcavity formed by collision of single-cycle self-induced transparency light pulses in a resonant medium.

The coherent interaction of extremely short light pulses with a resonant medium can result in the formation of population difference gratings. Such gratings have been created by pulses that are π/2 or smaller. This paper demonstrates that a microcavity with Bragg-like mirrors can be formed by colliding two single-cycle attosecond self-induced transparency pulses in the center of a two-level medium. The parameters of this structure can be quickly adjusted by increasing the number of collisions, which showcases the ability to control the dynamic properties of the medium on a sub-cycle time scale by using attosecond pulses.

Detailed Insight into the Behaviour of Chlorophyll a Fluorescence Transient Curves and Parameters during Different Times of Dark Adaptation in Sunflower Leaves

The reason for this examination is today’s wide usage of chlorophyll a fluorescence (ChlF) among researchers worldwide to measure photosynthetic efficiency. Although the instructions of the ChlF measuring device clearly emphasize the need for methodology adjustments, depending on the specific plant species, many researchers use the usual 30 min of dark adaptation before measurement. Namely, before any ChlF measurement, it is necessary to determine the specific duration of the leaf adaptation to the conditions of darkness of each plant tissue. Because of the numerous uses of the ChlF measurements, we decided to conduct this research to determine whether the appearance of the curves and parameter values depend on the time of sunflower leaf tissue adaptation to dark conditions. Therefore, this research aimed to examine the optimal adaptation time of sunflower tissue to dark conditions to obtain timely precise measurements and credible appearance of ChlF transient curves as well as accurate parameter values. The research was carried out on the sunflower hybrid Luka with 0, 15, 30, 45, 60, 75 and 90 min of dark adaptation in the vegetative, budding and flowering stages in the field conditions. According to the analyzed transient curves and parameters, it was determined that sunflower leaves should be kept in dark conditions for at least 15 min before the measurement of ChlF, which leads to the complete oxidation of PSII and the electron transport chain prior to a saturating pulse of light.

Intense pulsed light treatment for the management of meibomian gland dysfunction.

Meibomian gland dysfunction (MGD) is one of the most common disorders encountered by ophthalmologists, and its management can prove challenging for both clinicians and patients. Intense pulsed light (IPL), which has been historically used in the field of dermatology, has emerged as a tool to help improve meibomian gland function. The goal of this review is to assess the clinical efficacy, utility, and safety of IPL for the treatment of MGD. In recent randomized controlled trials, IPL has been shown to improve meibomian gland function, and subsequently tear film quality and dry eye symptoms. The mechanism of action still remains unclear. Recent literature suggests that IPL may also be used in conjunction with other therapies, such as meibomian gland expression, low-level light therapy, and thermal pulsation. Careful attention should be placed on each patient's Fitzpatrick skin type, as well as protecting the ocular structures to reduce the risk of adverse effects. Cost, accessibility, as well as a limited duration of efficacy may be drawbacks. There is significant evidence supporting that IPL may be used as a potential well tolerated and effective treatment for MGD, though there are certain caveats regarding its long-term efficacy, accessibility, and cost.

Evaluating the impact of pulsed light treatment on microbial and enzyme inactivation and quality attributes in fresh‐cut watermelon

AbstractThis study investigated the impact of pulsed light (PL) applied at a fluence of 4–12 J cm−2 (complying with U.S. Food and Drug Administration standards) on fresh‐cut watermelon, focusing on its efficacy in inactivating various food‐borne pathogenic gram‐positive (Escherichia coli and Staphylococcus aureus) and gram‐negative (Listeria monocytogenes and Salmonella) bacteria. The inactivation data were used to fit the log‐linear and Weibull kinetic models. Additionally, the impact of PL on physicochemical properties, lycopene content, total phenolic content, antioxidant activity, and pectin methylesterase (PME) residual activity (RA) was studied. The results demonstrated that the inactivation rate increases with the increase in fluence. Salmonella was most sensitive to PL, resulting in a reduction of 2.55 ± 0.08 log CFU g−1 and a higher kmax, whereas S. aureus was most resistant, with a reduction of 1.87 ± 0.24 log CFU g−1 and a lower kmax. The Weibull model was the best to predict the inactivation kinetics based on standard statistics and information theory criteria. For all assayed food‐borne pathogens, the inactivation curve showed non‐linearity with upward concavity except for L. monocytogenes, which followed a concave downward curve (β >1). Results showed that PL was effective in the retention of color, firmness, pH levels, total soluble solids, and titratable acidity, and also had a positive effect on enhancing the levels of essential components such as lycopene, total phenolic compounds, and antioxidant activity. Additionally, the PME RA significantly decreased with an increase in fluence due to structural modification. Therefore, PL can be explored to enhance fresh‐cut watermelon's safety and quality attributes.Practical ApplicationsThe implementation of this research holds significant potential for practical benefits in the fresh‐cut fruit industry. The findings could revolutionize processing practices, ensuring enhanced microbial safety, enzyme inactivation, and an extended shelf‐life of fresh‐cut watermelon. The study strongly contributes to preserving the desirable texture, color, and overall quality of the product, enhancing the retention of lycopene and other valuable antioxidants by standardizing the pulsed light treatment parameters while adhering to U.S. Food and Drug Administration standards for food application. Moreover, this research will scientifically contribute to addressing the critical challenges of foodborne outbreaks in the fresh‐cut fruit sector while providing consumers with a healthy, convenient food choice.