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Background: Alpha-fetoprotein (AFP) is a fetal protein that can indicate congenital anomalies such as Down syndrome and spinal canal blockage when detected at abnormal levels in pregnant women. Current AFP detection methods rely on invasive blood or serum samples, which require sophisticated equipment. From the many solutions proposed, colorimetric paper-based assays excel in point-of-care settings. The concept of paper-based ELISA (p-ELISA) enhances traditional methods, aligning with the ASSURED criteria for diagnostics in resource-limited regions. Despite success in microfluidic paper-based assay devices, laser printing remains underexplored for p-ELISA. Additionally, modifying the paper surface provides an additional layer of sensitivity enhancement., Results: In this study, we developed a novel laser-printed paper-based ELISA (LP-pELISA) for rapid, sensitive, and noninvasive detection of AFP in saliva samples. The LP-pELISA platform was fabricated by printing hydrophobic barriers on filter paper using a laser printer, followed by depositing hydroxyapatite (HAp) as an immobilization material for the antibodies. The colorimetric detection was achieved using AuNPs functionalized with anti-AFP antibodies and silver nitrate enhancement. The LP-pELISA exhibited a linear response for AFP detection in both buffer and saliva samples over a range of 1.0-800 ng mL -1 , with a limit of detection (LOD) reaching 1.0 ng mL -1 . The assay also demonstrated good selectivity, repeatability, reproducibility, and stability. The LP-pELISA was further validated by testing spiked human saliva samples, showing its potential for point-of-care diagnosis of congenital disabilities., Significance: The LP-pELISA is a noninvasive platform showcasing simplicity, cost-effectiveness, and user-friendliness, utilizing laser printing, hydroxyapatite modification, and saliva samples to efficiently detect AFP. Beyond its application for AFP, this method's versatility extends to other biomarkers, positioning it as a catalyst for the evolution of paper-based biosensors. The LP-pELISA holds promise as a transformative tool for point-of-care diagnostics, fostering advancements in healthcare with its innovative technology., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

A one-shot CO 2 laser-based strategy to generate conductive reduced graphene oxide (rGO) decorated with nanoceria (nCe) is proposed. The 2D/0D rGO-nCe films, integrated as catalytic sensing layers in paper-based sensors, were employed for on-site monitoring of indoor fogging treatments against Listeria monocytogenes (Lm), a ubiquitous pathogenic bacterium. The rGO-nCe laser-assisted synthesis was optimized to preserve the rGO film morphological and electron-transfer features and simultaneously integrate catalytic nCe. The films were characterized by microscopical (SEM), spectroscopical (EDX, Raman, and FTIR), and electrochemical techniques. The most performing film was integrated into a nitrocellulose substrate, and the complete sensor was assembled via a combination of xurography and stencil printing. The rGO-nCe sensor's catalytic activity was proved toward the detection of H 2 O 2 , obtaining sensitive determination (LOD = 0.3 µM) and an extended linear range (0.5-1500 µM). Eventually, the rGO-nCe sensor was challenged for the real-time continuous monitoring of hydrogen peroxide aerosol during no-touch fogging treatment conducted following the EU's recommendation for biocidal product use. Treatment effectiveness was proved toward three Lm strains characterized by different origins, i.e., type strain ATCC 7644, clinical strain 338, and food strain 641/6II. The sensor allows for discrimination and quantification treatments at different environmental biocidal amounts and fogging times, and correlates with the microbiological inhibition, promoting the proposed sensor as a useful tool to modulate and monitor no-touch treatments., (© 2024. The Author(s).)

Excessive emissions of heavy metals not only cause environmental pollution but also pose a direct threat to human health. Therefore, rapid and accurate detection of heavy metals in the environment is of great significance. Herein, we propose a method based on laser-induced breakdown spectroscopy (LIBS) combined with filter paper modified with bovine serum albumin-protected gold nanoclusters (LIBS-FP-AuNCs) for the rapid and sensitive detection of Cr 3+ and Mn 2+ . The filter paper modified with AuNCs was used to selectively enrich Cr 3+ and Mn 2+ . Combined with the multi-element detection capability of LIBS, this method achieved the simultaneous rapid detection of Cr 3+ and Mn 2+ . Both elements showed linear ranges for concentrations of 10-1000 μg L -1 , with limits of detection of 7.5 and 9.0 μg L -1 for Cr 3+ and Mn 2+ , respectively. This method was successfully applied to the determination of Cr 3+ and Mn 2+ in real water samples, with satisfactory recoveries ranging from 94.6% to 105.1%. This method has potential application in the analysis of heavy metal pollution.

The present study investigated the potential for solvent-assisted laser desorption coupled with flexible microtube plasma ionization mass spectrometry (SALD-FμTP-MS) as a rapid analytical technique for direct analysis of surface-deposited samples. Paper was used as the demonstrative substrate, and an infrared hand-held laser was employed for sample desorption, aiming to explore cost-effective sampling and analysis methods. SALD-FμTP-MS offers several advantages, particularly for biofluid analysis, including affordability, the ability to analyze low sample volumes (<10 μL), expanded chemical coverage, sample and substrate stability, and in situ analysis and high throughput potential. The optimization process involved exploring the use of viscous solvents with high boiling points as liquid matrices. This approach aimed to enhance desorption and ionization efficiencies. Ethylene glycol (EG) was identified as a suitable solvent, which not only improved sensitivity but also ensured substrate stability during analysis. Furthermore, the addition of cosolvents such as acetonitrile/water (1:1) and ethyl acetate further enhanced sensitivity and reproducibility for a standard solution containing amphetamine, imazalil, and cholesterol. Optimized conditions for reproducible and sensitive analysis were determined as 1000 ms of laser exposure time using a 1 μL solvent mixture of 60% EG and 40% acetonitrile (ACN)/water (1:1). A mixture of 60% EG and 40% ACN/water (1:1) resulted in signal enhancements and relative standard deviations of 12, 20, and 13% for the evaluated standards, respectively. The applicability of SALD-FμTP-MS was further evaluated by successfully analyzing food, water, and biological samples, highlighting the potential of SALD-FμTP-MS analysis, particularly for thermolabile and polarity diverse compounds.

This work presents the results of paper laser processing. It begins with the selection and examination of the processing parameters, then an examination of the properties of the modified papers and examples of applications of the developed modification method. The properties of laser-modified paper were studied using reflectance spectrophotometry to examine the colour aspects of the modified papers, scanning electron microscopy (SEM) and confocal microscopy for a morphological analysis, and Raman spectroscopy to analyse the papers under the influence of laser light. The influence of laser processing on the wettability of paper and the evenness of unprinted and printed paper was also investigated. The knowledge gained on paper surface modification with laser light was used to propose several applications, such as methods of marking, tactile detection, the controlled removal of optical brightener, ink, and metallised coatings from paper packaging, highlighting the design and aesthetics of paper. The developed laser-assisted method shows a promising, ecological approach to the design of many value-added paper products. [ABSTRACT FROM AUTHOR]

Since its introduction in 2014, laser-induced graphene (LIG) from commercial polymers has been gaining interests in both academic and industrial sectors. This can be clearly seen from its mass adoption in various fields ranging from energy storage and sensing platforms to biomedical applications. LIG is a 3-dimensional, nanoporous graphene structure with highly tuneable electrical, physical, and chemical properties. LIG can be easily produced by single-step laser scribing at normal room temperature and pressure using easily accessible commercial level laser machines and materials. With the increasing demand for novel wearable devices for biomedical applications, LIG on flexible substrates can readily serve as a technological platform to be further developed for biomedical applications such as point-of-care (POC) testing and wearable devices for healthcare monitoring system. This review will provide a comprehensive grounding on LIG from its inception and fabrication mechanism to the characterization of its key functional properties. The exploration of biomedicals applications in the form of wearable and point-of-care devices will then be presented. Issue of health risk from accidental exposure to LIG will be covered. Then LIG-based wearable devices will be compared to devices of different materials. Finally, we discuss the implementation of Internet of Medical Things (IoMT) to wearable devices and explore and speculate on its potentials and challenges., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

This bibliometric study analyzed the 100 most-cited papers about the use of lasers and their modalities in dentistry. A search strategy was created using specific keywords related to the topic. A comprehensive search was then conducted in the Web of Science Core Collection (WoS-CC) database up to July 2021. Papers that addressed the application of any type of laser and its modalities in dentistry were included. Each paper was cross-matched with the number of citations on Scopus and Google Scholar. The following data were extracted from papers: title, number of citations, authorship, country, year of publication, journal, study design, subject, laser type, and oral health outcomes. The VOSviewer software was used to generate bibliometric networks. The total number of citations ranged from 120 to 4,124 and 23 papers received more than 200 citations. Papers were published from 1964 to 2015. Most papers were from Europe (42%) and Anglo-Saxon America (27%). The USA was the country with more top 100 papers (25%). Papers were published mainly in Lasers in Surgery and Medicine (15%) and Lasers in Medical Science (7%). VOSviewer maps demonstrated the existence of national and international research collaborations among institutions and authors. Most studies had a laboratory design (57%) and were about restorative dentistry (32%) and periodontics (21%). This bibliometric study of the top 100 most-cited papers on lasers in dentistry allowed a quantitative and qualitative analysis of this very promising research field, revealing a net of collaboration and the importance of this topic in dentistry. [ABSTRACT FROM AUTHOR]

Paper‐based strain sensors (PSS) have broad prospects in disposable products due to their low cost and easy degradation as environmentally friendly materials. Herein, a strain sensor made of a laser‐induced carbonization electrode is created by direct laser writing with filter paper. The conductivity and gauge factor (GF) of this strain sensor are improved by adding lignin and applying strain engineering. This enables the sensor to simultaneously satisfy high sensitivity (GF ≈ 408 and 91) for weak tension and compression strain, respectively, and with long‐term reliability. The tensile strain GF factors of up to 201 are possible, even with a weak tensile strain of 0.00088%. Furthermore, the paper‐based sensor for monitoring physiological activities like finger gestures, pulsing, swallowing, and eye blinking is demonstrated. The facile fabrication and superior performance of PSS fabricated by direct laser writing with strain engineering may pave the way for promising applications of flexible, portable, and wearable electronic devices. [ABSTRACT FROM AUTHOR]

Motivated by the inevitable trend of the Internet of Everything, human-machine interaction technology has gradually been permeated into people's daily life. Receptive devices that capture human behaviors and responsive devices that provide machine feedback are key components of human-machine interface. While it is a great challenge to integrate receptive and responsive devices in a well-organized way due to the limitations of material properties and device structures. In this work, we investigate the formation of laser-induced graphene on Nomex paper and propose an efficient interactive strategy based on its piezoresistive and thermoacoustic effects. Functional integration of receiving instructions (pressure-sensing capability) and providing feedback (sound-emitting capability) can be achieved by simply assembling three layers of Nomex paper that have been laser-customized on both sides. The integrated device not only has a sensitive response (∼12 relative current change and ∼50 ms response time) to the pressure similar to a gentle finger press (∼10 kPa), but also can emit a high-quality sound signal with larger sound pressure levels (∼70 dB at 1 W/cm2 power density). Furthermore, two proof-of-concept demonstrations, a press-to-audio pad and a command-responding thermo-earphone, are presented to substantiate the feasibility in information exchange activities. [Display omitted] • Laser-induced graphene layers with favorable electrical conductivity are formed on Nomex paper. • Different conductive properties between double-sided laser-induced graphene across Nomex substrate are obtained by regulating laser power. • Pressure-sensing and sound-emitting capabilities are realized taking advantage of piezoresistive and thermoacoustic effects of laser-induced graphene. • Multifunctional integration is implemented by assembling three-layer Nomex paper that feature double-sided laser-induced graphene. [ABSTRACT FROM AUTHOR]

In the past 15 years, ambient ionization techniques have witnessed a significant incursion into the field of mass spectrometry imaging, demonstrating their ability to provide complementary information to matrix-assisted laser desorption ionization. Matrix-assisted laser desorption electrospray ionization is one such technique that has evolved since its first demonstrations with ultraviolet lasers coupled to Fourier transform-ion cyclotron resonance mass spectrometers to extensive use with infrared lasers coupled to orbitrap-based mass spectrometers. Concurrently, there have been transformative developments of this imaging platform due to the high level of control the principal group has retained over the laser technology, data acquisition software (RastirX), instrument communication, and image processing software (MSiReader). This review will discuss the developments of MALDESI since its first laboratory demonstration in 2005 to the most recent advances in 2021., (© 2021 John Wiley & Sons Ltd.)

Microcystin-LR (MC-LR), as a hepatotoxin, can cause liver swelling, hepatitis, and even liver cancer. In this study, MC-LR aptamer (Apt-3) modified graphene oxide (GO) was designed to enrich MC-LR in white jade snail (Achatina fulica) and pond water, followed by matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) analysis. Results indicated that the Apt-3/PEG/GO nanocomposites were highly specific to MC-LR, and the detection limit of MALDI-MS was 0.50 ng/mL. Moreover, the MC-LR can be released from nanocomposites at 75°C, thus, the reuse of Apt-3/PEG/GO is realized. Real sample analysis indicated that the Apt-3/PEG/GO nanocomposites coupled with MALDI-MS were efficient in detecting trace amounts of MC-LR in real samples. With the merits of being low cost, reusable, and easy to besynthesized, this Apt-3/PEG/GO MALDI-MS is expected to be comprehensively applied by anchoring suitable aptamers for different targets., (© 2023 Wiley-VCH GmbH.)

Development of high‐precision RGB patterning process is needed to implement high‐resolution micro display (OLEDoS) for next‐generation VR/AR products. In general, specially designed and manufactured masks are required to realize above 3,000ppi high‐resolution display in structured OLED material deposition. In this study, we implemented direct laser patterning IR‐fs optical system operating in MHz and GHz burst modes and evaluated its capability for precise micro‐drilling of alumino‐borosilicate glass materials. The fine hole‐shaped pattern is produced at a minimum of 5µm pitch level for about 0.6 inch area without sacrificing the glass strength. It is expected to contribute to the high precise manufacture of ultra fine mask (UFM) using thin glass platform corresponding to micro displays in the future. [ABSTRACT FROM AUTHOR]

Immunoassay is one of the most important clinical techniques for disease/pathological diagnosis. Mass spectrometry (MS) has been a popular and powerful readout technique for immunoassays, generating the mass spectrometric immunoassays (MSIAs) with unbeatable channels for multiplexed detection. The sensitivity of MSIAs has been greatly improved with the development of mass labels from element labels to small-molecular labels. MSIAs are also expended from the representative element MS-based methods to the laser-based organic MS and latest ambient MS, improving in both technology and methodology. Various MSIAs present high potential for clinical applications, including the biomarker screening, the immunohistochemistry, and the advanced single-cell analysis. Here, we give an overall review of the development of MSIAs in recent years, highlighting the latest improvement of mass labels and MS techniques for clinical immunoassays., (© 2022. Springer-Verlag GmbH Germany, part of Springer Nature.)

Excimer Laser Coronary Atherectomy (ELCA) is a well-established therapy that emerged for the treatment of peripheral vascular atherosclerosis in the late 1980s, at a time when catheters and materials were rudimentary and associated with the most serious complications. Refinements in catheter technology and the introduction of improved laser techniques have led to their effective use for the treatment of a wide spectrum of complex coronary lesions, such as thrombotic lesions, severe calcific lesions, non-crossable or non-expandable lesions, chronic occlusions, and stent under-expansion. The gradual introduction of high-energy strategies combined with the contrast infusion technique has enabled us to treat an increasing number of complex cases with a low rate of periprocedural complications. Currently, the use of the ELCA has also been demonstrated to be effective in acute coronary syndrome (ACS), especially in the context of large thrombotic lesions. • The ELCA procedure has become an established therapy for the treatment of a wide range of coronary lesions. • The ELCA treatment helps to complete uncrossable and undilatable coronary lesions, stent under-expansion, hard CTO cases. • The ELCA technique is also very useful in ACS, especially in cases in which intracoronary thrombotic burden is predominant. • The 0.9 mm ELCA-X80 catheters requires only a typical 0.014 guidewire, and have the potential to treat any type of calcified lesion. • The use of high energy pulse (80 flunce / 80 repetition rate) associated to contrast injection (Explosion Technique) is crucial in complex cases. [ABSTRACT FROM AUTHOR]

An electroanalytical lab-on-a-strip device for the direct extra-virgin olive oil (EVOO) antioxidant capacity evaluation is proposed. The lab-made device is composed of a CO 2 laser nanodecorated sensor combined with a cutter-plotter molded paper-strip designed for EVOOs sampling and extraction. Satisfactory performance towards the most representative o-diphenols of EVOOs i.e., hydroxytyrosol (HY) and oleuropein (OL) were achieved; good sensitivity (LOD HY  = 2 µM; LOD OL  = 0.6 µM), extended linear ranges (HY: 10-250 µM; OL: 2.5-50 µM) and outstanding reproducibility (RSD < 5%, n = 3) were obtained in rectified oil. The device was challenged for the extraction-free analysis of 15 different EVOO samples, with satisfactory recoveries (90-94%; RSD < 5%, n = 3) and correlation with classical photometric assays (r ≥ 0.91). The proposed device includes all analysis steps, needs 4 µL of sample, and returns reliable results in 2 min, resulting portable and usable with a smartphone., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

In this work we suggest a novel paradigm of social laser (solaser), which can explain such Internet inspired social phenomena as echo chambers, reinforcement and growth of information cascades, enhancement of social actions under strong mass media operation. The solaser is based on a well-known in quantum physics laser model of coherent amplification of the optical field. Social networks are at the core of the solaser model; we define them by means of a network model possessing power-law degree distribution. In the solaser the network environment plays the same role as the gain medium has in a physical laser device. We consider social atoms as decision making agents (humans or even chat bots), which possess two (mental) states and occupy the nodes of a network. The solaser establishes communication between the agents as absorption and spontaneous or stimulated emission of socially actual information within echo chambers, which mimic an optical resonator of a convenient (physical) laser. We have demonstrated that social lasing represents the second order nonequilibrium phase transition, which evokes the release of coherent socially stimulated information field represented with the order parameter. The solaser implies the formation of macroscopic social polarization and results in a huge social impact, which is realized by viral information cascades occurring in the presence of population imbalance (social bias). We have shown that decision making agents follow an adiabatically time dependent mass media pump, which acts in the network community reproducing various reliable scenarios for information cascade evolution. We have also shown that in contrast to physical lasers, due to node degree peculiarities, the coupling strength of decision making agents with the network may be enhanced [Formula: see text] times. It leads to a large increase of speed, at which a viral message spreads through a social media. In this case, the mass media pump supports additional reinforcement and acceleration of cascade growth. We have revealed that the solaser model in some approximations possesses clear links with familiar Ising and SIS (susceptible-infected-susceptible) models typically used for evaluating a social impact and information growth, respectively. However, the solaser paradigm can serve as a new platform for modelling temporal social events, which originate from "microscopic" (quantum-like) processes occurring in the society. Our findings open new perspectives for interdisciplinary studies of distributed intelligence agents behavior associated with information exchange and social impact., (© 2022. The Author(s).)

Liquid crystal (LC) lasers use a layer of chiral nematic liquid crystal to form a self‐organising resonant cavity. When doped with fluorescent dye and suitably excited, they form versatile micro‐lasers with high efficiencies, low thresholds, and selective wavelength emission across a continuous range of the visible spectrum. This, combined with their scalable fabrication, makes them attractive candidates for a wide variety of photonic applications, including laser displays. This paper includes a review of the principles of operation, of recent enhancements that are advancing the technology closer to market, and concludes with demonstrations of LC lasers used for medical imaging and low‐speckle holography. [ABSTRACT FROM AUTHOR]

In the world of terahertz bands, terahertz beam deflection has gradually attracted substantial attention, due to its great significance in wireless communications, high-resolution imaging and radar applications. In this paper, a low-reflection and fast-fabricated terahertz beam deflection device has been realized by utilizing graphene oxide paper. Using laser direct writing technology, graphene oxide has been patterned as a specific sample. The thickness of the graphene oxide-based terahertz devices is around 15–20 μm, and the processing takes only a few seconds. The experimental results show that the beam from this device can achieve 5.7° and 10.2° deflection at 340 GHz, while the reflection is 10%, which is only 1/5 of that of existing conventional devices. The proposed device with excellent performance can be quickly manufactured and applied in the fields of terahertz imaging, communication, and perception, enabling the application of terahertz technology. [ABSTRACT FROM AUTHOR]

Solid state light sources for projection displays have shown tremendous progress over the recent years. Their application usage is ranging from low luminance near to eye projection for augmented reality glasses to mainstream projectors. This presentation will share some of the latest progresses for laser and LEDs for Near‐to‐eye (NTE) displays and will describe important design challenges such as package integration and power efficiency. Besides, High Current LEDs are further pushing the limits and bring LED based projection light engines on eye‐to‐eye brightness level with lamp & laser‐based systems ranging up to 5,000 ANSI lumens. [ABSTRACT FROM AUTHOR]

Thin and lightweight head‐mounted displays with polarized laser backlights and holographic optics were proposed. To make the distance between the eyes and the displays even shorter, we propose the backlight with an inverted wedge‐shaped light guide plate. We confirmed that it has luminous uniformity and a high degree of polarization. [ABSTRACT FROM AUTHOR]

The current international guidelines identify tumescent ablative techniques such as laser thermal ablation (EVLA) and radiofrequency (RFA) to be the gold standard in varicose vein surgery. New-generation lasers have been introduced, which have high wavelengths (1940 and 2000 nm) and therefore with a greater affinity for water than the old generation (980- and 1470-nm lasers). The purpose of the study was to evaluate the biological effect and the temperatures produced during the use of lasers with different wavelengths (980, 1470, and 1940 nm) and with optical fibers with different emission (radial diverging at 60° and radial with cylindrical mono-ring) on in vitro model. Porcine liver was used as an in vitro model. The laser control units used had 3 different wavelengths: 980, 1470, and 1940 nm. The optical fibers used were 2: the Corona 360 fiber (mono-ring radial fiber) and the infinite fiber (cylindrical mono-ring fiber). The laser operating parameters used included the delivery of 6 W in continuous wave (CW) mode with a standard 10 s/cm pull-back. Eleven measurements were made for each fiber and for each laser, for a total of 66 measurements. We performed measurements of the maximum transverse diameter produced with laser irradiation to evaluate the biological effectiveness of the treatment. During laser irradiation, we performed measurements of both of the temperatures reached on the external surface of the porcine tissue, near the tip of the laser catheter, and the temperatures reached inside the irradiated tissue by using a digital laser infrared thermometer with apposite probe. The calculation of the statistical significance (p-value) was obtained with the ANOVA method with two between factors. The comparison study of the maximum transverse diameter (DTM) of the lesion produced on the target tissue demonstrated the absence of statistically significant differences between the 1470-nm laser and the 1940-nm laser regardless of the type of fiber used. It was not possible to perform measurements of the maximum transverse diameter produced with the 980-nm laser as this produced no visible effect on the model. The comparison study of the temperatures developed during and immediately after the treatment instead showed higher maximum surface temperatures (TSM) and a higher thermal increase (IT) regardless of the type of fiber used in a statistically significant way (respectively, p 0.002 and 0.012) when using the 980-nm laser versus the 1940-nm laser. Comparing instead the 980-nm laser with 1470 nm, there were no differences in TI recorded during the procedure but a significantly higher VTI (p 0.029). The experiment conducted with the new generation laser, compared with those of the first and second generation, shows how this works overall at lower temperatures with the same effectiveness., (© 2023. The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.)

In this work, fabrication of frequency selective surface filters by coating paper with silver ink and subsequent laser etching the frequency filter pattern has been investigated. Three filter structures consisting of a combination of square and ring patches operating at 102, 113, and 126 GHz and with corresponding signal attenuation of −15.2, −15.4, and −14.5 dB were fabricated and simulated; −5 dB bandwidths were following, 93.3–112.2 GHz, 101.9–121.1 GHz, and 112.7–132.3, respectively. Also, the proposed screen printing with assistive laser etching could be used to reduce the number of used screens. Furthermore, paper based fabrication using a biodegradable ink could be an alternative fabrication process in future electronic manufacturing. [ABSTRACT FROM AUTHOR]

The latest achievements of GaN‐based laser diodes are summarized, focused on two topics: watt‐class high‐power edge‐emitting lasers and milliwatt‐class vertical‐cavity surface‐emitting lasers. These light sources have high efficiency and high reliability, which are suitable for various display applications such as laser projectors and/or ARIVR displays. [ABSTRACT FROM AUTHOR]

In this paper, our novel epitaxial nanowire‐based surface‐emitting lasers and self‐powered, wavelength distinguishable photodetectors in the ultraviolet are reviewed, and their potentially applications to portable sensing and imaging systems for extended environment awareness are discussed. [ABSTRACT FROM AUTHOR]

A photochemical precursor to the 5-endo-10,11-dihydroazepine nitrenium ion (1) was synthesized and used to characterize the intermediate by laser flash photolysis and stable product analysis. In addition, DFT calculations were carried out on the nitrenium ion. These results were compared with earlier studies on the diphenylnitrenium ion in order to ascertain the effect of the 2 carbon bridge on the reactions and properties of 1. It is shown that the geometric constraints provided by the bridging group (a) destabilize the triplet state of 1 relative to the singlet state (b) substantially increase the lifetime of 1 relative to Ph 2 N + by inhibiting the unimolecular cyclization pathway possible in the latter and (c) modestly increases the barrier for nucleophilic addition to the ring carbons., (© 2022. The Author(s), under exclusive licence to European Photochemistry Association, European Society for Photobiology.)

We improved the three-dimensional spatial resolution of laser scanning transmission microscopy by exploiting the saturated absorption of dye molecules. The saturated absorption is induced by the high-intensity light irradiation and localises the signal within the centre of the focal spot. Our numerical calculation indicates that the spatial resolution in transmission imaging is significantly improved for both lateral and axial directions using nonlinear transmitted signals induced by saturated absorption. We experimentally demonstrated the improvement of the three-dimensional resolution by observing fine structures of stained rat kidney tissues, which were not able to be visualised by conventional laser scanning transmission microscopy., (© 2021 Royal Microscopical Society.)

The safety and efficacy of laser hair removal have been well established through many clinical studies and through clinical use over the past 25 years. A laser hair removal device that protects the epidermis by utilizing cryogen spray cooling (CSC) is widely used internationally. In darker skin types, post-inflammatory hyperpigmentation (PIH) can occur after laser hair removal. In particular, laser hair removal with CSC is known to cause crescent-shaped or ring-shaped PIH. In this experiment, we report a visualization of this PIH mechanism. The laser used in this experiment is a 755-nm-long-pulsed alexandrite laser. Graph paper was treated with this laser to assess for thermal damage. We investigated changes in thermal damage due to differences in laser spot size, fluence output, and laser beam angle in relation to the graph paper. When using a spot size of 18 mm, we observed that higher fluences caused crescent-shaped thermal damage on the margins of the treated graph paper. It was also confirmed that when the hand piece is not held perpendicular to the skin, the laser-treated area is expanded and the CSC range is narrowed. These factors caused the area of thermal damage to widen. This widening causes ring-shaped thermal injury, leading to PIH. We treated graph paper using a hair removal laser with CSC to investigate the mechanism of crescent or ring-shaped thermal damage. Laser treatment on graph paper is effective as a test for defects in the CSC device. Factors that cause inadequate cooling, which leads to PIH, are large spot size, high fluence, not holding the laser hand piece perpendicular to the skin, and malfunctioning of CSC device. [ABSTRACT FROM AUTHOR]

• Graphene oxide/reduced graphene oxide paper was obtained by Ultraviolet laser. • The reduction degree of graphene oxide can be adjusted by changing the laser power. • The as-prepared papers exhibit anisotropically deformation triggered by ethanol vapor. This report aims to illustrate a highly effective method to obtain a kind of graphene oxide (GO)/reduced graphene oxide (RGO) paper by Ultraviolet (UV) laser direct writing method. Due to removing the oxygen-containing groups and introducing the layered micro-nano structures on one side of the GO film. The as-prepared GO/RGO papers exhibit anisotropically deformation triggered by ethanol vapor and could enable the potential applications for stimuli-response actuators. [ABSTRACT FROM AUTHOR]

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• Mathematical and physical analyses of the introduced problem. • Reporting a serious error in an important dimensionless parameter. • Indicating that the reported numerical results are completely erroneous. This is a comment on the paper [Optics and Laser Technology 128 (2020) 106233; https://doi.org/10.1016/j.optlastec.2020.106233 ] titled "Exact coupled solution for photothermal semiconducting beams using a refined multi-phase-lag theory". Herein, we report a serious error in an important dimensionless parameter employed in the problem, revealing that the defined parameter is dimensional and wrong. Accordingly, all given numerical results are based on this serious mistake, and are completely erroneous. [ABSTRACT FROM AUTHOR]

Optical tweezers are widely used to investigate biomolecules and biomolecular interactions. In these investigations, the biomolecules of interest are typically coupled to microscopic beads that can be optically trapped. Since high-intensity laser beams are required to trap such microscopic beads, laser-induced heating due to optical absorption is typically unavoidable. This chapter discusses how to identify, quantify, and control thermal effects in optical tweezers. We provide a brief overview of the reported causes and effects of unwanted heating in optical tweezers systems. Specific details are provided on methods to perform a temperature-independent trap calibration procedure. Finally, an effective temperature-control system is presented, and we discuss the operation of this system as well as the methods to measure the temperature at the optically trapped particle., (© 2022. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

In this paper, a simple method is described for visually demonstrating that the wavelength of light reduces when entering a medium of higher refractive index. When a violet laser (405 nm) is reflected off the surface of a Blu-ray disc (track spacing 320 nm) diffraction cannot occur since the wavelength is greater than the track spacing. However, in water (refractive index 1.33) the wavelength of violet light reduces to 304.5 nm and therefore first-order diffraction can occur when a violet laser is reflected off a Blu-ray disc submerged in water. A violet laser was reflected off a DVD in air, and one diffraction order was seen, but two orders were observed when the disc was immersed in water. Red, green, and violet lasers were reflected off CD, DVD and Blu-ray discs and the number of observed diffraction orders compared with theory. When a violet laser was reflected off a CD in air, three diffraction orders were seen, however five orders were observed in water. The use of tonic water in the experiments enabled the diffraction orders to be seen more easily because violet light causes the quinine in tonic water to fluoresce.

In recent years, Laser Diode have been used in various applications. Initially, Infrared and Red Lasers began to be used for optical desks and optical communication applications. Blue‐Violet Laser was developed and adopted for Blu‐ray Disc. Since then, Blue and Green Lasers have been developed and Viable Laser Diode have begun to be used for various Display applications. This paper introduces the Laser Diode that have been developed so far, their applications, and various Display applications that are expected in the future. [ABSTRACT FROM AUTHOR]

In this paper, we propose a simple yet generic and versatile method to measure the position of a moving body as a function of time. Apart from very basic equipment such as carts and wheels, only a laser pointer or a similar device and a smartphone are necessary. By attaching a source of light to a cart and video filming its movement on a horizontal plane under the gravitational force, the position of the cart as a function of time can be recorded without any calibration and using one of the many free apps. The obtained results for the cart acceleration under a constant force were in very good agreement with Newton's second law. The inexpensive equipment and the possibility of taking data at very short intervals allow different experiments in mechanics to be performed, for example to demonstrate the conservation of energy and momentum in mechanics or to investigate complex movements.

Objectives: Body surface area (SA) is a widely used physical measure incorporated into multiple thermophysiology and evolutionary biology models currently estimated in humans either with empirical prediction equations or costly whole-body laser imaging systems. The introduction of low-cost 3D scanners provides a new opportunity to quantify total body (TB) and regional SA, although a critical question prevails: can these devices acquire the quality of depth information and process this initial data to form a mesh that has the fidelity needed to generate accurate SA estimates?, Materials and Methods: This question was answered by comparing SA estimates calculated using images from four commercial 3D scanners in 108 adults to corresponding estimates acquired with a whole-body laser system. This was accomplished by processing initial mesh data from all devices, including the laser system, with the same universal software adapted specifically for repairing mesh gaps, identifying landmarks, and generating SA measurements., Results: TB SA measured on all four 3D scanners was highly correlated with corresponding laser system estimates (R 2 s, 0.98-0.99; all p < 0.001) with some small but significant mean differences (-0.19 to 0.06 m 2 ); root-mean square errors (RMSEs) were small (0.02-0.03 m 2 ); and significant bias was present for one device. Qualitatively similar results (e.g., R 2 s, 0.78-0.95; mean Δs, -0.05 to 0.02 m 2 ; RMSEs, 0.01-0.03 m 2 ) were present for trunk, arm, and leg SA comparisons., Discussion: The current study observations demonstrate that low-cost and practical 3D optical scanners are capable of accurately quantifying TB and regional SA, thus opening new opportunities for evaluating human phenotypes and related physiological characteristics., (© 2021 Wiley Periodicals LLC.)