External Light Source Research Articles

High-Precision Optical Fiber-Based Lickometer.

Quantifying and analyzing licking behavior can offer valuable insights into fundamental neurobiological mechanisms controlling animal consummatory behaviors. Lickometers are typically based on electrical properties, a strategy that comes with limitations, including susceptibility to electrical interference and generation of electrical disturbances in electrophysiological measurements. While optical lickometers offer an alternative method to measure licks and quantify fluid intake in animals, they are prone to false readings and susceptibility to outside light sources. To overcome this problem, we propose a low-cost open-source lickometer that combines a restricted infrared beam defined by optical fibers, with a poke design that allows easy access to the tongue while limiting access of other body parts and external light sources. This device also includes features for detecting nose pokes and presenting visual cues during behavioral tasks. We provide validation experiments that demonstrate the optical lickometer's reliability, high-sensitivity and precision, and its application in a behavioral task, showcasing the potential of this tool to study lick microstructure in combination with other techniques, such as imaging of neural activity, in freely moving mice.

In-situ and wavelength-dependent photocatalytic strain evolution of a single Au nanoparticle on a TiO2 film

Photocatalysis is a promising technique due to its capacity to efficiently harvest solar energy and its potential to address the global energy crisis. However, the structure–activity relationships of photocatalyst during wavelength-dependent photocatalytic reactions remains largely unexplored because it is difficult to measure under operating conditions. Here we show the photocatalytic strain evolution of a single Au nanoparticle (AuNP) supported on a TiO2 film by combining three-dimensional (3D) Bragg coherent X-ray diffraction imaging with an external light source. The wavelength-dependent generation of reactive oxygen species (ROS) has significant effects on the structural deformation of the AuNP, leading to its strain evolution. Density functional theory (DFT) calculations are employed to rationalize the induced strain caused by the adsorption of ROS on the AuNP surface. These observations provide insights of how the photocatalytic activity impacts on the structural deformation of AuNP, contributing to the general understanding of the atomic-level catalytic adsorption process.

3D position and pose measurement based on coded light field

AbstractHigh‐precision relative position and attitude measurement technology has a wide range of applications in aerospace and industrial production. Currently, the commonly used method for measurement is based on visual cooperative signs. However, its accuracy significantly decreases as the distance increases. Therefore, a relative positioning system is designed based on light field spatial coding and visual recognition. The projector emits spatially encoded structured light within the coverage of the light field, while the receiving end captures, identifies, measures the code, and calculates its pose in the light field coordinate system. Compared with the traditional measurement method, the measurement accuracy of this system does not decrease greatly with the increase in distance, the measurement distance can be adjusted in real‐time and does not depend on an external light source. By changing the projection pattern with different resolutions without changing hardware systems, it can adjust effective measurement distance accordingly. Theoretical and experimental results show that the proposed method can maintain measurement accuracy with the increase in distance.

Integration of Myrica rubra-based N-doped carbon dots with Fe3S4 as excellent peroxidase mimics for colorimetric assay and smartphone-based intelligent sensing of p-aminophenol in waters.

To realize the reutilization of waste Myrica rubra in the analytical field, we synthesized Myrica rubra-based N-doped carbon dots (MN-CDs) and further anchored them onto the surface of Fe3S4 to fabricate Fe3S4@MN-CD nanocomposites. The as-fabricated nanocomposites possessed higher peroxidase-mimetic activity than its two precursors, resulting from the synergistic effect between them, and could catalyze colorless 3,3',5,5'-tetramethylbenzidine (TMB) into deep blue oxTMB with a strong 652-nm absorption. Under optimized conditions (initial solution pH, 3.5; incubation temperature, 35 ℃; Fe3S4@MN-CD concentration, 50µg mL-1, and 652-nm absorption), Fe3S4@MN-CDs were employed for colorimetric assay of p-aminophenol (p-AP) with wide linear range (LR, 2.9-100 µM), low detection limit (LOD, 0.87 µM), and satisfactory recoveries (86.3-105%) in environmental waters. Encouragingly, this colorimetric assay provided the relative accuracy of 97.0-99.4% as compared withconventional HPLC-UV detection. A portable smartphone-based colorimetric application was developed by combining the Fe3S4@MN-CD-based visually chromogenic reaction with a "Thing Identify" APP software. Besides, we engineered an image-capturing device feasible for field use, in which the internal-compact sealing prevented external light source from entering photography chamber, thereby reducing light interference, and also the bottom light source enhanced the intensity of blue imaging. This colorimetric platform exhibited satisfactory LR (1-500 µM), low LOD (0.3 µM), and fortification recoveries (86.6-99.6%). In the chromogenic reaction catalyzed by Fe3S4@MN-CDs, ·O2- played a key role in concomitant with the participation of •OH and h+. Both the colorimetric assay and smartphone-based intelligent sensing show great promising in on-site monitoring of p-AP under field conditions.

Sonosynthetic Cyanobacteria Oxygenation for Self-Enhanced Tumor-Specific Treatment.

Photosynthesis, essential for life on earth, sustains diverse processes by providing nutrition in plants and microorganisms. Especially, photosynthesis is increasingly applied in disease treatments, but its efficacy is substantially limited by the well-known low penetration depth of external light. Here, ultrasound-mediated photosynthesis is reported for enhanced sonodynamic tumor therapy using organic sonoafterglow (ultrasound-induced afterglow) nanoparticles combined with cyanobacteria, demonstrating the proof-of-concept sonosynthesis (sonoafterglow-induced photosynthesis) in cancer therapy. Chlorin e6, a typical small-molecule chlorine, is formulated into nanoparticles to stimulate cyanobacteria for sonosynthesis, which serves three roles, i.e., overcoming the tissue-penetration limitations of external light sources, reducing hypoxia, and acting as a sonosensitizer for in vivo tumor suppression. Furthermore, sonosynthetic oxygenation suppresses the expression of hypoxia-inducible factor 1α, leading to reduced stability of downstream SLC7A11 mRNA, which results in glutathione depletion and inactivation of glutathione peroxidase 4, thereby inducing ferroptosis of cancer cells. This study not only broadens the scope of microbial nanomedicine but also offers a distinct direction for sonosynthesis.

Far-red emitting Li2TiO3: Cr3+ phosphor: Synthesis, luminescence properties and potential applications

The Cr[Formula: see text]-activated phosphor can emit far-red light under the excitation of an external light source, mainly due to the transition of the outermost electrons of Cr[Formula: see text] from the 2E level to the 4A2 level in a strong crystal field environment. A novel far-red Li2TiO3: Cr[Formula: see text] phosphor was prepared by the solid-state method. Under the excitation of 356[Formula: see text]nm, the Li2TiO3: Cr[Formula: see text] phosphors emit intense far-red light in 600–850[Formula: see text]nm with a central wavelength of 732[Formula: see text]nm. The emission band of all samples was matched with the absorption bands of phytochrome P[Formula: see text]. The experimental data and theoretical calculation confirmed that Cr[Formula: see text] is surrounded by a strong crystal field environment. The effect of Cr[Formula: see text] doping concentration on the luminescence intensity was analyzed. These research works demonstrate that far-red Li2TiO3: Cr[Formula: see text] phosphors have potential applications in plant growth lights.

Classical and quantum light-induced non-adiabaticity in molecular systems

The exchange of energy between electronic and nuclear motion is the origin of non-adiabaticity and plays an important role in many molecular phenomena and processes. Conical intersections (CIs) of different electronic potential energy surfaces lead to the most singular non-adiabaticity and have been intensely investigated. The coupling of light and matter induces conical intersections, which are termed light-induced conical intersections (LICIs). There are two kinds of LICIs, those induced by classical (laser) light and those by quantum light like that provided by a cavity. The present work reviews the subject of LICIs, discussing the achievements made so far. Particular attention is paid to comparing classical and quantum LICIs, their similarities and differences and their relationship to naturally occurring CIs. In contrast to natural CIs, the properties of which are dictated by nature, the properties of their light-induced counterparts are controllable by choosing the frequency and intensity (or coupling to the cavity) of the external light source. This opens the door to inducing and manipulating various kinds of non-adiabatic effects. Several examples of diatomic and polyatomic molecules are presented covering both dynamics and spectroscopy. The computational methods employed are discussed as well. To our opinion, the young field of LICIs and their impact shows much future potential.

Engineered Luminescent Oncolytic Vaccinia Virus Activation of Photodynamic-Immune Combination Therapy for Colorectal Cancer.

Oncolytic virus therapy is currently regarded as a promising approach in cancer immunotherapy. It has greater therapeutic advantages for colorectal cancer that is prone to distant metastasis. However, the therapeutic efficacy and clinical application of viral agents alone for colorectal cancer remain suboptimal. In this study, an engineered oncolytic vaccinia virus (OVV-Luc) that expresses the firefly luciferase gene is developed and loaded Chlorin e6 (Ce6) onto the virus surface through covalent coupling, resulting in OVV-Luc@Ce6 (OV@C). The OV@C infiltrates tumor tissue and induces endogenous luminescence through substrate catalysis, resulting in the production of reactive oxygen species. This unique system eliminates the need for an external light source, making it suitable for photodynamic therapy (PDT) in deep tissues. Moreover, this synergistic effect between PDT and viral immunotherapy enhances dendritic cell maturation, macrophage polarization, and reversal of the immunosuppressive microenvironment. This synergistic effect has the potential to convert a "cold" into a "hot" tumor, it offers valuable insights for clinical translation and application.

ReS2-MoS2 heterojunction nanotube FET with superlattice structures for ultrasensitive detection of miRNA

Ultrasensitive detection of cancer biomarkers holds immense importance in facilitating the early diagnosis and treatment of cancer. Compared to conventional detection techniques, field-effect transistor (FET) biosensors have demonstrated substantial potential in achieving sensitive detection of cancer biomarkers. However, the ultrasensitive FET still remains great challenges due to the limited electron transport capacity and sensitivity of channel materials. Herein, we employed rhenium disulfide-molybdenum disulfide nanotube (ReS2-MoS2 NT) featuring superlattice structures as channel materials in FET biosensors for the highly sensitive detection of cancer biomarker miRNA-21. More concretely, ReS2-MoS2 NT featuring superlattice structures was synthesized using the anodic aluminum oxide (AAO) template sacrifice method and atomic layer deposition (ALD) method. The electrical properties of single ReS2-MoS2 NT FET were regulated by adjusting the total layers and number of heterojunction interfaces, and the optimal number of heterojunction interfaces of 7 was obtained. Finally, FET biosensors utilizing the network ReS2-MoS2 NT as the channel materials were fabricated and exhibited remarkable sensitivity in detecting miRNA-21 under an external light source. The linear range for detection spanned from 10 aM to 1 nM, with an exceptionally low detection limit of 2.1 aM. This study holds promise for replacing current channel materials and surpassing the detection threshold of cancer biomarkers in the future.

Topological Nature of Radiation Asymmetry in Bilayer Metagratings.

Manipulating radiation asymmetry of photonic structures is of particular interest in many photonic applications such as directional optical antenna, high efficiency on-chip lasers, and coherent light control. Here, we proposed a term of pseudopolarization to reveal the topological nature of radiation asymmetry in bilayer metagratings. Robust pseudopolarization vortex with an integer topological charge exists in P-symmetry metagrating, allowing for tunable directionality ranging from -1 to 1 in synthetic parameter space. When P-symmetry breaking, such vortex becomes pairs of C points due to the conservation law of charge, leading to the phase difference of radiation asymmetry from π/2 to 3π/2. Furthermore, topologically enabled coherent perfect absorption is robust with customized phase difference at will between two counterpropagating external light sources. This Letter can not only enrich the understanding of two particular topological photonic behaviors, i.e., bound state in the continuum and unidirectional guided resonance, but also provide a topological view on radiation asymmetry, opening an unexplored avenue for asymmetric light manipulation in on-chip laser, light-light switch, and quantum emitters.

Preparation of nanocomposite material based on Porphyrin and electrochemical analysis for green fuel production

In the current environmental pollution situation, using green fuel sources such as H2 gas to overcome the challenge of pollution and resource depletion is a useful solution. This research used the acid-base neutralization method with the recombination process to successfully fabricate CuFe2O4/TCPP nanocomposites. The morphological and structural properties of the materials were evaluated by scanning electron microscopy (SEM), X-ray diffraction (XRD) which show that the resulting material has a structure consisting of TCPP filaments with a diameter of about 20-30 nm and a length of µm, interspersed with CuFe2O4 particles with sizes in the range of 100 nm. The electrochemical properties of the as-prepared material film were investigated by Cyclic Voltammetry (CV) and electrochemical impedance spectroscopy (EIS) on a glassy carbon electrode with a 3-electrodes system. The results show the appearance of electrochemical characteristics of copper ferrite/porphyrin hybrid materials and especially the change of electrochemical characteristics when this nanocomposite was irradiated by an external light source. These results are expecting to apply this material in the photocatalytic process to produce green fuel H2 from water.

Photoresponsive CHA-Integrated Self-Propelling 3D DNA Walking Amplifier within the Concentration Localization Effect of DNA Molecular Framework Enables Highly Efficient Fluorescence Bioimaging.

While three-dimensional (3D) DNA walking amplifiers hold considerable promise in the construction of advanced DNA-based fluorescent biosensors for bioimaging, they encounter certain difficulties such as inadequate sensitivity, premature activation, the need for exogenous propelling forces, and low reaction rates. In this contribution, a variety of profitable solutions have been explored. First, a catalytic hairpin assembly (CHA)-achieved nonenzymatic isothermal nucleic acid amplification is integrated to enhance sensitivity. Subsequently, one DNA component is simply functionalized with a photocleavage-bond to conduct a photoresponsive manner, whereby the target recognition occurs only when the biosensor is exposed to an external ultraviolet light source, overcoming premature activation during biodelivery. Furthermore, a special self-propelling walking mechanism is implemented by reducing biothiols to MnO2 nanosheets, thereby propelling forces that are self-supplied to a Mn2+-reliant DNAzyme. By carrying the biosensing system with a DNA molecular framework to induce a unique concentration localization effect, the nucleic acid contact reaction rate is notably elevated by 6 times. Following these, an ultrasensitive in vitro detection performance with a limit of detection down to 2.89 fM is verified for a cancer-correlated microRNA biomarker (miRNA-21). Of particular importance, our multiple concepts combined 3D DNA walking amplifier that enables highly efficient fluorescence bioimaging in live cells and even bodies, exhibiting a favorable application prospect in disease analysis.

System for Self-excited Targeted Photodynamic Therapy Based on the Multimodal Protein DARP-NanoLuc-SOPP3.

Despite the significant potential of photodynamic therapy (PDT) as a minimally invasive treatment modality, the use of this method in oncology has remained limited due to two serious problems: 1) limited penetration of the excitation light in tissues, which makes it impossible to affect deep-seated tumors and 2) use of chemical photosensitizers that slowly degrade in the body and cause photodermatoses and hyperthermia in patients. To solve these problems, we propose a fully biocompatible targeted system for PDT that does not require an external light source. The proposed system is based on bioluminescent resonance energy transfer (BRET) from the oxidized form of the luciferase substrate to the photosensitizing protein SOPP3. The BRET-activated system is composed of the multimodal protein DARP-NanoLuc-SOPP3, which contains a BRET pair NanoLuc-SOPP3 and a targeting module DARPin. The latter provides the interaction of the multimodal protein with tumors overexpressing tumor-associated antigen HER2 (human epidermal growth factor receptor type II). In vitro experiments in a 2D monolayer cell culture and a 3D spheroid model have confirmed HER2-specific photo-induced cytotoxicity of the system without the use of an external light source; in addition, experiments in animals with subcutaneous HER2-positive tumors have shown selective accumulation of DARP-NanoLuc-SOPP3 on the tumor site. The fully biocompatible system for targeted BRET-induced therapy proposed in this work makes it possible to overcome the following limitations: 1) the need to use an external light source and 2) the side phototoxic effect from aberrant accumulation of chemical photosensitizers. The obtained results demonstrate that the fully protein-based self-excited BRET system has a high potential for targeted PDT.

Efficient Photocatalytic Luminous Textile for Simulated Real Water Purification: Advancing Economical and Compact Reactors.

The growing worldwide problem of wastewater management needs sustainable methods for conserving water supplies while addressing environmental and economic considerations. With the depletion of freshwater supplies, wastewater treatment has become critical. An effective solution is needed to efficiently treat the organic contaminants departing from wastewater treatment plants (WWTPs). Photocatalysis appears to be a viable method for eliminating these recalcitrant micropollutants. This study is focused on the degradation of Reactive Black 5 (RB5), a typical contaminant from textile waste, using a photocatalytic method. Titanium dioxide (TiO2) was deposited on a novel luminous fabric and illuminated using a light-emitting diode (LED). The pollutant degrading efficiency was evaluated for two different light sources: (i) a UV lamp as an external light source and (ii) a cold LED. Interestingly, the LED UV source design showed more promising results after thorough testing at various light levels. In fact, we note a 50% increase in mineralization rate when we triple the number of luminous tissues in the same volume of reactor, which showed a clear improvement with an increase in compactness.

Emergency Microscope Light Modification by External Source in Absence of Power Supply

Introduction: Microscope is an instrument for visualizing fine detail of an object so that observer can observe the object being examined in detail. The object of examination vary from cells (normal or pathologic), microorganism (such as parasite and bacterium), and even non biological part. There are several types of microscope, one of the oldest forms and still used today is the light microscope. A light microscope relied on continuous light source to operate. The most common source for today's microscopes is an incandescent tungsten-halogen bulb, which is solely electric dependent, positioned in a reflective housing that projects light through the collector lens and into the sub-stage condenser. Current situations sometimes require readiness for conducting microscopic examination anytime, anywhere. Unfortunately, problem occur if the electricity goes out, most people will not be able to continue their microscopic observations. This problem raises the question of what if in an emergency it is necessary to carry out a microscopic examination but unfortunately there is no power source. Below we propose emergency modification efforts so that the microscope can still be used even in conditions without a power source.
 Aims: to modify an electric light microscope in such a way that it can continue to be used in the absence of an electrical power source using external source of light.
 Discussion: Adding an external source of light is a brilliant approach in order to make the electric dependent light microscope still useable in emergency condition.
 Conclusion: it is possible to modify an electric light microscope in the condition of no electric source available and make it operable.

Bioluminescence-induced photocatalysis on semiconducting oxide nanosheets

ABSTRACT A novel semiconductor photocatalytic reaction system employing a photo-emitting enzyme as an internal light source is pro-posed in the present study. The system completely overturns common sense that conventional photocatalytic reactions must require irradiation from an external light source. A horseradish peroxidase (HRP) catalyzing oxidative bioluminescence reaction of luminol in the presence of H2O2 and manganate nanosheets (MNSs) with a narrow bandgap were utilized for an internal light source and semiconductor photocatalysts, respectively, and both of them coexisted in a same reactant solution. In other words, nano-sized light sources were highly dispersed in the solution, resulting in photo-excitation of MNSs over the entire solution. Photo-activated MNSs simultaneously caused oxidation and reduction, where platinum hexachloride anions (PtCl6 2-) were utilized as a model substance to be reacted photocatalytically. According to X-ray absorption near edge spectroscopy (XANES) of MNSs after the photocatalytic reaction, the anions were mainly transformed into solid phases of PtO2 and/or Pt(OH)4 by reacting with holes in MNSs. In contrast, a control experiment without HRP, i.e. a dark experiment, did not leave any evidence for photocatalytic reaction of PtCl6 2-. The detailed mechanism and the advantages/disadvantages of the proposed unique system are explained.

Negative and positive dysphotopsia

Dysphotopsia are responsible for complaints of that small percentage of pseudophakic subjects who are not satisfied with their vision. They are divided into negative and positive. Positive dysphotopsia (PD) are described by patients as glare, light streaks, light arcs, flashes of light, and starbursts produced by an external light source, whereas negative dysphotopsia (ND) is a dark temporal peripheral arc‐shaped shadow or line.PD are related to the nature of the inserted intraocular lens (IOL). The incidence rate of PD at 1 year after cataract surgery is 0.2–2.2%, and there have been no reports of PD in intraocular surgeries other than cataract surgery to date. The cause of ND is unknown, and many concepts trying to explain its pathophysiology were proposed, including a small pupil, an axial space behind the iris, and a sharp optic edge, the increased angle kappa, the nasal location of the pupil relative to the optical axis, with in‐the‐bag IOLs (and not in ciliary sulcus‐, anterior chamber‐, or scleral suture‐fixated IOLs), and a correlation with coverage of the anterior capsule edge, interaction between the anterior capsulorhexis with the intraocular lens, shorter eyes and a higher implanted IOL power, position of the haptic, and neuroadaptive component.

Illumination Methods for the Stereomicroscope, Including Use of Colored Filters for Image Contrast Enhancement

Stereo light microscopes (SLM) or dissecting microscopes are used in many different sciences, industries, and technologies. The objective for the SLM falls into two major categories: common main objective (CMO) using a single objective with prisms that split the image for each eye, and the Greenough style employing one microscope for each eye. In Europe, in the late 1800s, Carl Zeiss in conjunction with Otto Schott, designed a SLM using an Italian prism design that made images of the object correctly oriented. Two main illumination methods used with the SLM are transmitted and reflected light. Transmitted light illumination using a light source built into the base or with an attachable substage base utilizing an external light source. Some manufacturers provide additional illumination methods such as darkfield and polarizing light filters. Reflected illumination using visible light can be divided into five common illumination methods and two different ways to achieve fluorescent illumination. After a brief discussion of types of filters and sources, practical application of reflected light with the SLM substage attachable base with diffuse reflector and colored filters is shown to enhance visibility of certain colored particles while minimizing the visibility of unwanted colored particles.

An in situ-activated and chemi-excited photooxygenation system based on G-poly(thioacetal) for Aβ1-42 aggregates.

The abnormal aggregation of Aβ proteins, inflammatory responses, and mitochondrial dysfunction have been reported as major targets in Alzheimer's disease (AD). Photooxygenation of the amyloid-β peptide (Aβ) is viewed as a promising therapeutic intervention for AD treatment. However, the limitations of the depth of the external light source passing through the brain and the toxic side effects on healthy tissues are two significant challenges in the photooxidation of Aβ aggregates. We proposed a method to initiate the chemical stimulation of Aβ1-42 aggregate oxidation through H2O2 and correct the abnormal microenvironment of the lesions by eliminating the cascading reactions of oxidative stress. The degradable G-poly(thioacetal) undergoes cascade release of cinnamaldehyde (CA) and thioacetal triggered by endogenous H2O2, with CA in turn amplifying degradation by generating more H2O2 through mitochondrial dysfunction. A series of novel photosensitizers have been prepared and synthesized for use in the photodynamic oxidation of Aβ1-42 aggregates under white light activation. The nanoparticles (BD-6-QM/NPs) self-assembled from BD-6-QM, bis[2,4,5-trichloro-6-(pentoxycarbonyl) phenyl] ester (CPPO), and G-poly(thioacetal) not only exhibit H2O2-stimulated controlled release but also can be chemically triggered by H2O2 to generate singlet oxygen to inhibit Aβ1-42 aggregates, reducing the Aβ1-42-induced neurotoxicity.

From Rocks to Pixels: A Protocol for Reproducible Mineral Imaging and its Applications in Machine Learning

Identifying minerals is essential for geology, mineral exploration, engineering, and environmental sciences. Recent advances in machine learning have illustrated its potential as a fast, cost-effective, and reliable tool for identifying minerals from photographs or photomicrographs. However, in the recent literature, few studies have been dedicated to image acquisition. Machine learning generally requires reproducible, high-quality data to perform complicated tasks such as mineral identification to avoid common pitfalls. In this paper, we propose a practical image acquisition protocol for optical microscopes. This protocol focuses on ensuring reproducibility and enhancing image quality. To favor reproducibility, we detail dealing with camera errors, using reference color gauges, and establishing experimental parameters such as the external light source and temperature. For image enhancement, we explain the importance of lighting and its impact on machine learning precision, selection of the objective, and white balance calibration. In addition, we trialed the protocol on heavy mineral concentrate from till samples (20 species) with a typical deep learning model and it revealed that minor lighting modification (<5% difference in one channel) significantly increased misclassification rates: kyanite from 6.4% to 24.9% and monazite from 6.5% to 42.9%.