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Ultrafast luminescence in Mg was investigated in the infrared region, between 0.35 and 1.05 eV, and compared with the results for Al, using a luminescence upconversion technique. The luminescence intensity of these metals at 0.9 eV was higher than that of platinum with a similar surface roughness under the same excitation density. Although the Mg and Al are adjacent to each other in the periodic table and belong to "light metals," having similar band structures, their luminescence spectra differ significantly. Pronounced peak structures were found for Mg and these were attributed to interband transitions within the conduction bands consisting of 3s and 3p orbitals overlapped on the intraband continuum, based on density functional theory band structure calculation. This result is in contrast to the interband luminescence in noble metals (Au, Ag, and Cu) under continuous-wave blue laser excitation, where the final states have been assigned to the d bands. A comparison of the spectra of rough and specular surfaces suggested that the surface roughness is not essential for mitigating wavenumber mismatch for intraband transitions. The luminescence from light metals, which are harmless to humans, will be attractive for biomedical applications. [ABSTRACT FROM AUTHOR]

We have studied the aging-induced degradation effect and the related mechanism of blue and ultraviolet (UV) laser diodes (LDs). First of all, the F parameter value, leakage current, and yellow luminescence intensity of LDs all increase after 24 h of the aging process, indicating that one of the reasons for the degradation of UV LDs may be the increase of the non-radiative recombination center in the material. Second, irreversible damage may be found on the front cavity surface of the UV and blue LDs. Due to the large UV photon energy, water molecules in the environment atmosphere are ionized to form OH− ions, which combine with dust in air to form SiO2 sediments and then attach to the front cavity surface. In addition, a large photon energy may cause damage to the anti-reflection film on the front cavity surface and lead to a too-high local temperature near the cavity surface, resulting in molten Ga droplets. Both sediment and the precipitation of molten GaN on the cavity surface will directly affect the function of the front cavity surface and the output power of the LD. In order to improve the reliability of the GaN-based UV LDs, it is necessary to reduce the density of material defects, select more stable coating materials on cavity facets, and improve the sealing property of the device package. [ABSTRACT FROM AUTHOR]

The carrier recombination behavior of GaN-based blue laser diodes (LDs) is studied and analyzed by experiments and simulation calculations before lasing, with a particular focus on the role of Auger recombination. It is found that Auger recombination plays a crucial role in the decrease in differential efficiency and threshold current of GaN-based blue LDs. The theoretical calculation results show that a large Auger recombination rate may lead to a dominant recombination channel before lasing, which could exceed the radiation recombination and result in an obvious decrease in the differential efficiency. Such a high Auger recombination will dissipate a large number of carriers in the quantum well, resulting in deterioration of device performance, a higher threshold current and a lower efficiency. This work presents a method to evaluate Auger recombination through differential efficiency and also provides evidence that suppressing the Auger recombination rate is beneficial to improve the performance of blue LDs. [ABSTRACT FROM AUTHOR]

Introduction: The competition between intra-row weeds and cultivated vegetables for nutrients is a major contributor for crop yield reduction. Compared with manual weeding, intelligent robots can improve the efficiency of weeding operations. Methods: This study proposed a novel mechanical-laser collaborative intra-row weeding device structure. A slider-crank mechanism size optimization algorithm was proposed, and the correctness of the algorithm was verified by ADMAS software. Finally, the crank and link lengths were determined to be 87 mm and 135 mm, respectively. The resistance of triangular weeding knives with different penetration angles and edge angles in the soil was simulated and analyzed using EDEM software. The simulation results show that the triangular weeding knife with a soil penetration angle of 0 ° and an edge angle of 30 ° encountered the least resistance. In addition, weed control experiments with different powers and lasers were conducted using 200 W NIR and 200 W blue lasers. The experimental results show that the time it took for a 50 W blue laser and a 100 W NIR laser to remove small weeds was approximately between 0.3 and 0.4 s, and the time it took for a 50 W blue laser to remove larger weeds was approximately between 0.5 and 0.6 s. The time it took for 75 W and 50 W NIR lasers to remove weeds was more than 1 s. Results: Based on the above research results, a prototype of a mechanical-laser collaborative intra-row weeding device was successfully built. Discussion: This study provides a new idea for the field of intelligent weeding. The simulation and experimental results can provide a reference for the research and development of mechanical weeding and laser weeding equipment. [ABSTRACT FROM AUTHOR]

The two‐dimensional characterization of the Au/Ni/thin p+‐GaN/n−‐GaN structure, which is a part of a junction barrier Schottky structure, is demonstrated by scanning internal photoemission microscopy (SIPM) method. In the SIPM photoyield image using a blue laser, small photocurrents based on the internal photoemission effect by electron injection across the metal/semiconductor interface (from Ni to GaN) are detected in the center of the electrode. On the periphery, large photocurrents in the opposite direction are detected. These currents are caused by the hole injection from Ni into p+‐GaN layer and the electrical field in the laterally extended depletion layer at the edge. By using a violet laser, large photocurrents based on the fundamental absorption generated in the depletion layer of the n−‐GaN layer are uniformly detected over the electrode. It is conformed that SIPM can be available for quasi‐three‐dimensional characterization of this structure. [ABSTRACT FROM AUTHOR]

In nitride‐based laser diodes, the poor conductivity of the p‐type region, higher light absorption, and the difficult processing of an ohmic p‐contact with low resistance are major challenges. Recently interband tunnel junctions (TJs) have been used to replace much of the hole transport layers by electron transport layers, and also to allow for two n‐type contacts. In this work, GaN‐based laser diode stacks with TJs are analyzed. The devices are grown with plasma‐assisted molecular beam epitaxy and include two waveguides with active regions consisting of 25 nm wide InGaN quantum well (QW), each, which are connected through a TJ. A second TJ is placed on top to eliminate the p‐type contact. In this study, the time‐dependent spectral behavior of such structures is analyzed by streak camera measurements. The two QWs have different lasing thresholds and emission wavelength. Using the temporal resolution of the streak camera, a lasing onset of the second QW a few nanoseconds after the first one is observed. Single shot measurements show unusual intensity oscillations from both QWs, however, one is stable and the other laser diode (LD) has irregular oscillations. [ABSTRACT FROM AUTHOR]

In this work, it is aimed to study the interplay of different longitudinal mode combs corresponding to higher‐order lateral modes of broad‐area Fabry–Pérot‐type laser diodes. Coherent coupling of longitudinal modes of different mode combs influences the near‐ and far‐field pattern of the diode. Herein, commercial state‐of‐the‐art high‐power laser diodes based on the (Al,In)GaN material system in the blue spectral range with a 40 μm broad ridge are investigated. To spectrally resolve the different lateral modes, a sequential combination of a high‐resolution double grating spectrometer and a Fabry–Pérot interferometer (FPI) is used. The grating spectrometer acts as bandpass with a spectral width smaller than the free spectral range (FSR) of the FPI. The FPI with a finesse of approximately F=60$ℱ = 60$ boosts the resolution to 0.08 pm. A spectral clustering of lateral modes with increasing current and also a variation of the number of distinguishable lateral modes between 7 and 11 are observed. Within the current range from 1.25Ith to 2.25Ith, there is no clear evidence for coherent coupling. It is concluded that mode‐pulling is not strong enough to coherently couple modes on the investigated time and wavelength range. [ABSTRACT FROM AUTHOR]

Gallium nitride (GaN)‐based semiconductor laser diodes (LDs) have garnered significant attention due to their promising applications. However, high‐power LDs face serious degradation issues that limit their practical use. This study investigates the degradation factors of 437 nm and 6.3 W LDs by comparing light–current–voltage (L–I–V) characteristics, transmission electron microscopy (TEM), cathodoluminescence (CL), and secondary ion mass spectroscopy (SIMS) before and after 1000‐h aging. The diffusion of mirror coating from the resonant cavity surface is identified as a key factor contributing to high‐power LD degradation, which has not been reported in milliwatt‐level LDs. Meanwhile, the mechanisms behind the LD degradation are profiled and summarized together with the diffusion and other factors. On basis of the mechanism exploration, an anti‐aging technology for high‐power GaN‐based LDs is developed by using aluminum nitride for passivation layer and sapphire materials for mirror film. This anti‐aging technology has been verified, and a nearly ten‐time degradation suppression is achieved from 1000 h. This study elucidates the degradation mechanisms of high‐power GaN LDs and provides an effective technology to extend their lifespan, thereby prompting the practical applications of high‐power LDs. [ABSTRACT FROM AUTHOR]

Cancer cells have the ability to undergo an unlimited number of cell divisions, which gives them immortality. Thus, the cancer cell can extend the length of its telomeres, allowing these cells to divide unlimitedly and avoid entering the state of senescence or cellular apoptosis. One of the main effects of photobiomodulation (PBM) is the increase in the production of adenosine triphosphate (ATP) and free radicals, mainly reactive oxygen species (ROS). Existent data indicates that high levels of ROS can cause shortening and dysfunctional telomeres. Therefore, a better understanding of the effects induced by PBM on cancer cell telomere maintenance is needed. This work aimed to evaluate the effects of low-power red laser (658 nm) and blue LED (470 nm) on the TRF1 and TRF2 mRNA levels and telomere length in human breast cancer cells. MCF-7 and MDA-MB-231 cells were irradiated with a low-power red laser (69 J cm-2, 0.77 W/cm-2) and blue LED (482 J cm-2, 5.35 W/cm-2), alone or in combination, and the relative mRNA levels of the genes and telomere length were assessed by quantitative reverse transcription polymerase chain reaction. The results suggested that exposure to certain red laser and blue LED fluences decreased the TRF1 and TRF2 mRNA levels in both human breast cancer cells. Telomere length was increased in MCF-7 cells after exposure to red laser and blue LED. However, telomere length in MDA-MB-231 was shortened after exposure to red laser and blue LED at fluences evaluated. Our research suggests that photobiomodulation induced by red laser and low-power blue LED could alter telomere maintenance and length. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the subjective effect of office-based blue laser therapy for inferior turbinate hypertrophy in patients with nasal obstruction. Methods: Patients with nasal obstruction who underwent office-based blue laser for the inferior turbinate hypertrophy between October 2022 and December 2023 were included in the study. The two outcome measures used to gauge the improvement in nasal obstruction and success of surgery were the Nasal Obstruction Symptom Evaluation (NOSE) scale and the Visual Analogue Scale (VAS). Patient's level of comfort during the procedure was also rated using a 10-point VAS scale. Results: A total of 14 patients were included in this study. The mean age of the study group was 41.47 ± 18.52 and the F/M ratio was 4.67. All patients reported significant improvement in nasal breathing. The mean NOSE score decreased significantly from 13.07 ± 3.89 pre-operatively to 2.64 ± 2.43 post-operatively (p = 0.002). Similarly, the mean VAS score decreased from 7.43 ± 0.85 to 2.0 ± 1.57 (p = 0.002) following surgery. The procedure was well-tolerated by all participants and the mean total score ranged from 6 to 9 with an average of 7.59 ± 1.34. Conclusion: Office-based blue laser therapy for inferior turbinate hypertrophy may be an effective treatment modality for nasal obstruction from the patient's perspective. Although the procedures were tolerated well with no complications noted, these results should be cautiously interpreted until studies using objective measures are conducted. [ABSTRACT FROM AUTHOR]

The synthesis of carbon dots (CDs) is gaining wide-ranging interest due to their broad applicability, owing to their small size and luminescence. CDs were prepared from charcoal via a one-step process using laser ablation in liquid without the use of reagents. The adopted method was based on the use of a commercially available continuous wave (CW) laser diode emitting a 450 nm wavelength and, for the liquid, a phosphate-buffered saline (PBS) solution, routinely used in the biological field. Photoluminescence analysis revealed fluorescence, at 480 nm, increasing with laser irradiation time. The atomic force microscopy (AFM) of the CDs revealed an average sphere shape with a size of about 10 nm. Biodegradable polycaprolactone (PCL), typically adopted in biomedicine applications, was used as a matrix to show the preserved luminescence, ideal for the non-invasive monitoring of implanted scaffolds in tissue engineering. [ABSTRACT FROM AUTHOR]

Continuous-wave lasers generated bubbles in microfluidic channels are proposed for applications such as needle-free jet injection due to their small size and affordable price of these lasers. However, water is transparent in the visible and near-IR regime, where the affordable diode lasers operate. Therefore, a dye is required for absorption, which is often unwanted in thermocavitation applications, such as vaccines or cosmetics. In this work, we explore a different mechanism of the absorption of optical energy. The microfluidic channel wall is partially covered with a thin gold layer, which absorbs light from a blue laser diode. This surface absorption is compared with the conventional volumetric absorption by a red dye. The results show that this surface absorption can be used to generate bubbles without the requirement of a dye. However, the generated bubbles are smaller and grow slower when compared to the dye-generated bubbles. Furthermore, heat dissipation in the glass channel walls affects the overall efficiency. Finally, degradation of the gold layer over time reduces the reproducibility and limits its lifetime. Further experiments and simulations are proposed to potentially solve these problems and optimize the bubble formation. Our findings can inform the design and operation of microfluidic devices used in phase transition experiments and other cavitation phenomena, such as jet injectors or liquid dispensing for bio-engineering. [ABSTRACT FROM AUTHOR]

Laser ceramics have emerged as promising candidates of solid-state laser gain media. However, most laser ceramics are currently focused on lasing in the infrared wavelength range. The very limited options of host materials and the increased optical scattering losses at shorter wavelengths within ceramics have greatly limited the development of visible laser ceramics. Here we report visible laser ceramics with a composition of 0.5%Pr3+,5%Y3+:SrF2, in which a visible (orange) laser oscillation at 605 nm has been successfully achieved at room temperature pumped by InGaN blue laser diodes with a maximum slope efficiency of 8.1%. The ceramics were fabricated by vacuum hot pressing (VHP) of wet-chemistry synthesized 0.5%Pr3+,5%Y3+:SrF2 powders, followed by hot isostatic pressing (HIP). It was found that the visible laser ceramics exhibited a lower optical scattering loss along the processing pressure direction of the VHP process, indicating a uniaxial anisotropy in optical transmission within the ceramics. To our best knowledge, the current work is the first report on visible laser ceramics lasing in the orange region at ambient temperature, fabricated from chemically synthesized powders, which could pave the way for future scientific research on and industrial applications of more sophisticated and cost-effective visible laser ceramics. [ABSTRACT FROM AUTHOR]

Organic photoresponsive materials, which change their physical properties upon irradiation with light, are attracting tremendous scientific attention, as they offer a flexible and sustainable platform for developing various optoelectronic devices. In this work, photoinduced magnetization switching in two carbazole‐functionalized organic molecules, (9H‐carbazol‐9‐yl)(4‐chlorophenyl)methanone (ClPhCz) and (9H‐carbazol‐9‐yl)(2,4‐dichlorophenyl)methanone (DClPhCz) is reported for the first time. It was found that stabilization of the triplet excited state in those molecules is long enough for a net change in magnetic moment to be detected with a SQUID magnetometer. The change in magnetic moment upon excitation with a blue light laser was larger in ClPhCz, remaining high upon repeating the photoirradiation. In contrast, DClPhCz exhibited a smaller magnetic response, which gradually decreased upon repeating the experiment. [ABSTRACT FROM AUTHOR]

Micro/nanoscale lasers that span the entire visible spectrum, especially those in red, green, and blue colors, are not only essential for a variety of optical devices but also have important applications in visible color communication, multi‐color fluorescence sensing, and wavelength division multiplexing. Despite the great efforts made to achieve multi‐color lasing using a variety of approaches, on‐chip white light emission and even red, green, and blue multi‐color lasers still suffer from considerable challenges in micro‐nano structures. Here, CdSxSe1−x, CdS, and ZnS micro‐tripod structures are successfully prepared using chemical vapor deposition approaches. The micro‐photoluminescence (µ‐PL) spectra and PL‐mapping of these micro‐tripods reveal various emissions at 630, 508, and 460 nm, respectively. Additionally, white‐light emissions based on these composition‐tunable tripods are realized through an end‐coupling structure system. Moreover, room‐temperature modes tunable lasers are observed clearly from three legs of these micro‐tripods, with a low threshold of ≈48.39 µJ cm−2 and a high quality factor of 1227.3. The realization of micro‐tripods‐based lasers may provide an innovative way for highly integrated photonic circuits and communications. [ABSTRACT FROM AUTHOR]

Breast cancer remains a significant global health challenge, spurring ongoing investigations into innovative treatment approaches. Low-level laser therapy (LLLT) has emerged as a promising non-invasive therapeutic avenue of interest. This research delves into the impact of LLLT on the cytotoxicity of the MCF-7 breast cancer cell line, employing lasers emitting various wavelengths. The objective is to assess whether diverse LLLT wavelengths elicit disparate cytotoxic responses, shedding light on LLLT's potential as a targeted breast cancer treatment. MCF-7 cell cultures were subjected to lasers of varying wavelengths, including blue (473 nm), red (660 nm), and near-infrared (780 nm). Each wavelength was delivered at four different power levels: 10, 25, 45, and 65 mW, with exposure durations of 60, 300, 600, and 900 s. Cellular responses, encompassing factors such as cell viability, and cytotoxicity were assessed using WST-1 assays technique. Statistical analysis was performed to discern the wavelength-specific impacts of low-level laser therapy (LLLT) on MCF-7 cells. The study revealed that the blue laser had the least noticeable adverse impact on MCF-7 breast cancer cell lines, leading to the highest cell survival rate of 107.62% after 24 h. The most severe toxicity occurred when the laser was used at 45 mW for 900 s, resulting in cell viability ranging from 81.85% to 107.62%. As for cell viability after exposure to the red laser, the mildest harmful effect was observed at 45 mW power for 60 s, resulting in a cell survival rate of 147.62%. Conversely, the most significant toxic response occurred at 10 mW power for 60 s, resulting in a cell viability of 91.56%. In contrast, when employing infrared laser irradiation, the least substantial cytotoxic effect on MCF-7 cells was observed at 10 mW power for 600 s, resulting in the highest cell viability of 109.37% after 24 h. The most pronounced cytotoxic effect was observed by infrared laser (780 nm) at 25 mW power for 900 s, leading to the lowest viability of 32.53%. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to conduct a network meta-analysis to compare the diagnostic efficacy of diverse novel endoscopic techniques for detecting gastric Helicobacter pylori infection. Methods: From inception to August 2023, literature was systematically searched across Pubmed, Embase, and Web of Science databases. Cochrane’s risk of bias tool assessed the methodological quality of the included studies. Data analysis was conducted using the R software, employing a ranking chart to determine the most effective diagnostic method comprehensively. Convergence analysis was performed to assess the stability of the results. Results: The study encompassed 36 articles comprising 54 observational studies, investigating 14 novel endoscopic techniques and involving 7,230 patients diagnosed with gastric H. pylori infection. Compared with the gold standard, the comprehensive network meta-analysis revealed the superior diagnostic performance of two new endoscopic techniques, Magnifying blue laser imaging endoscopy (M-BLI) and high-definition magnifying endoscopy with i-scan (M-ISCAN). Specifically, M-BLI demonstrated the highest ranking in both sensitivity (SE) and positive predictive value (PPV), ranking second in negative predictive value (NPV) and fourth in specificity (SP). M-I-SCAN secured the top position in NPV, third in SE and SP, and fifth in PPV. Conclusion: After thoroughly analyzing the ranking chart, we conclude that M-BLI and M-I-SCAN stand out as the most suitable new endoscopic techniques for diagnosing gastric H. pylori infection [ABSTRACT FROM AUTHOR]

Colonoscopies are widely available, but there are cases where insertion can be difficult, even for experienced endoscopists. EC-760XP/L, a new ultrasmall-diameter long scope, may be useful in such cases. This single-center retrospective study included 39 cases where colonoscope insertion was difficult even when previously conducted by an experienced endoscopist. The primary outcome was the cecal intubation time using EC-760XP/L compared to the time used in a previous examination with a standard scope. The secondary outcomes were the cecum intubation rate, intestinal cleanliness level, adenoma detection rate, polyp detection rate, sedative use rate, occurrence of adverse events, and pain experience. A comparison of cecal intubation times between EC-760XP/L and the standard scope showed that insertion times were significantly lower with EC-760XP/L (9.5 min) compared to the standard scope (19 min) (p < 0.01). The standard scope achieved cecal intubation in 30 cases (76.9%), whereas EC-760XP/L reached the cecum in all cases (p < 0.01). Pain was observed in 3 cases (8.3%) with the EC-760XP/L, which was significantly lower than the 22 cases (56.4%) with the standard scope (p < 0.01). In conclusion, EC-760XP/L proved to be useful in cases where colonoscope insertion was difficult. [ABSTRACT FROM AUTHOR]

Next‐generation high‐brightness lighting faces a big challenge in developing laser‐drivable color‐converting materials with effective thermal management. Herein, a new material architecture of Al2O3‐Y3Al5O12: Ce3+ (YAG: Ce) transparent composite ceramics coated with Al film (TCC@Al) is proposed. The as‐prepared material shows the highest thermal conductivity (29.3 W m−1 K−1) among YAG: Ce‐related transparent ceramics (TC) ever reported owing to the combination role of short‐range thermal conduction of Al2O3 microcrystals and long‐range thermal conduction of Al film. Temperature‐dependent photoluminescence (PL) spectra and femtosecond transient absorption (fs‐TA) spectra evidence the importance of thermal management, whereby the luminescent loss of TCC@Al is only 8.92% at 450 K and is far smaller than TC counterpart (15.86%). Importantly, no obvious luminescence saturation is detected upon 20 W mm−2 blue laser irradiation and the inhomogeneous angular color distribution is suppressed by the scatter of Al2O3 microcrystals, yielding uniform white light with ultra‐high luminous flux (LF) of 4294 lm@20 W mm−2 and luminous efficacy (LE) of 215 lm W−1. As a consequence, the present TCC@Al‐converted laser‐driven lighting prototype exhibits much better optical performance than the commercial TC‐based one. [ABSTRACT FROM AUTHOR]

Purpose: The antibacterial properties of silver nanoparticles (AgNPs) are extensively identified. In large quantities, they might be harmful. So many fields of nanotechnology have shown a great deal of interest in the development of an environmentally friendly, efficient method for synthesizing metal nanoparticles. Because of its antibacterial and antifungal properties toward a wide range of microbes, chitosan silver nanoparticles (AgNPs@Cs) constitute a newly developing class of bio-nanostructured hybrid materials. Furthermore, the use of photothermal therapy (PTT) has been suggested as a means of elimination of germs. These light-stimulated treatments are minimally invasive and have a few side effects. In the present work, the antibacterial effect of AgNPs at low concentrations; prepared by chemical and green methods as antimicrobial and photothermal agents in photothermal therapy; with laser irradiation were explored as combined treatment against MRSA, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Methods: Silver nanoparticles were produced in two ways. First, by sodium borohydrides, second, by chitosan (as a natural eco-friendly reducing, and capping agent). The nanostructure of AgNPs and AgNPs@Cs was confirmed by UV–visible spectrometer, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIRs), and direct light scattering (DLS). The antibacterial activity of the prepared nanoparticles and the laser irradiation was tested against three bacterial species of zoonotic importance; MRSA, Pseudomonas aeruginosa, and Klebsiella pneumoniae; and was evaluated by measuring their minimum inhibitory concentrations (MIC). Results: Silver nanoparticles produced by the two methods had spherical shapes with nearly the same particle size. The analysis of DLS showed that AgNPs were very stable with zeta potential − 28.8 mv, and 47.7 mv by chemical and chitosan synthesis, respectively. Furthermore, AgNPs@Cs showed higher antibacterial activity toward the tested bacterial species than AgNPs by chemical method. Additionally, the bacterial viability using photothermal laser therapy was reduced compared to laser and AgNPs alone. The bactericidal activities were higher when laser diode was coupled with AgNPs@Cs than by chemical reduction. Conclusion: The laser combined treatment had a higher antimicrobial effect than AgNPs alone or laser irradiation alone. [ABSTRACT FROM AUTHOR]

A simple method for reducing the linewidth of a diode laser while maintaining high output power is described. It is based on a dispersive prism and a thin etalon for retroreflective feedback. The etalon creates two weak external cavities that provide spectral selectivity that is periodic with a period equal to the etalon's free spectral range. The method was applied to a multimode blue laser diode, which in the absence of feedback features a linewidth of several nanometers. The spectral properties of the laser were investigated for different etalon thicknesses and operating currents and tested in the presence of temperature fluctuations. With a SF11 equilateral uncoated prism near Brewster's angle and a 0.3 mm-thick uncoated fused silica etalon, the linewidth was reduced 20-fold to 70 pm (3.6 cm−1) with an output power of 3 W at a current of 2.15 A. The largest diode current probed was 2.75 A, which resulted in a linewidth of 100 pm (5.1 cm−1) and an output power of 4 W. In contrast to the use of, for example, a volume Bragg grating, a high degree of flexibility is afforded as the same prism–etalon pair can be used across the visible and near infrared. [ABSTRACT FROM AUTHOR]

The efficiency of current GaN-based blue laser diodes (LDs) is limited by the high resistance of a thick p-AlGaN cladding layer. To reduce the operation voltage of InGaN blue LDs, we investigated optimum LD structures with an indium tin oxide (ITO) partial cladding layer using numerical simulations of LD device characteristics such as laser power, forward voltage, and wall-plug efficiency (WPE). The wall-plug efficiency of the optimized structure with the ITO layer was found to increase by more than 20% relative to the WPE of conventional LD structures. In the optimum design, the thickness of the p-AlGaN layer decreased from 700 to 150 nm, resulting in a significantly reduced operation voltage and, hence, increased WPE. In addition, we have proposed a new type of GaN-based blue LD structure with a dielectric partial cladding layer to further reduce the optical absorption of a lasing mode. The p-cladding layer of the proposed structure consisted of SiO2, ITO, and p-AlGaN layers. In the optimized structure, the total thickness of the ITO and p-AlGaN layers was less than 100 nm, leading to significantly improved slope efficiency and operation voltage. The WPE of the optimized structure was increased relatively by 25% compared to the WPE of conventional GaN-based LD structures with a p-AlGaN cladding layer. The investigated LD structures employing the ITO and SiO2 cladding layers are expected to significantly enhance the WPE of high-power GaN-based blue LDs. [ABSTRACT FROM AUTHOR]

Thermally robust and highly stable bulk luminescent materials are essential for advancing high‐power laser‐driven lighting. In this study, we report a yellow–green LuAG:Ce–Al2O3 eutectic, synthesized using the laser‐heated pedestal growth (LHPG) technique. The emission intensity of the eutectics reaches a maximum at an Al2O3 content of 20% due to the enhanced light scattering. Additionally, owing to the high thermal conductivity of Al2O3, the prepared LuAG:Ce–Al2O3 eutectic exhibits low thermal quenching, with only a 5% loss in luminescence observed at 150°C, along with a high luminance saturation threshold of approximately 15.8 W·mm−2. When irradiated under blue laser excitation at 7.9 W, the prepared LuAG:Ce–Al2O3 eutectic demonstrates a luminous flux of 1917 lm and a luminous efficacy of 242.4 lm·W−1. These results highlight that the potential of LuAG:Ce–Al2O3 eutectics as luminescent materials for high‐power laser‐driven lighting applications. [ABSTRACT FROM AUTHOR]

Phosphor ceramics are considered to be promising color converters for high‐brightness laser lighting. However, current laser lighting usually suffers from a poor color rendering index (Ra ∼70) when using a single‐structured phosphor ceramic, due to the deficiencies in the cyan‐green and red components of the luminescence spectra. In this study, a series of Ca3Sc2Si3O12:Ce3+, Mn2+ (CSS:Ce3+, Mn2+) phosphor ceramics were prepared for the first time using a solid‐state reaction method. Based on the efficient energy transfer from Ce3+ to Mn2+ (with an energy transfer efficiency of ∼33.3%), these ceramics exhibit three distinct emission peaks appearing at 505, 580, and 680 nm, covering the cyan‐green, yellow, and deep red‐light regions, respectively. Additionally, the ceramics display excellent thermal stability, with a thermal quenching temperature (T0.5) exceeding 160°C. Finally, a laser lighting source was constructed by combining the CSS:Ce3+, Mn2+ ceramic with a blue laser diode. By optimizing the Mn2+ concentration, a tunable color from cyan‐green to white was achieved, and the resulting Ra and luminous efficacy of the white light were 86 and 65 lm/W, respectively. These results demonstrate that the CSS:Ce3+, Mn2+ phosphor ceramic is an excellent color converter for full‐color laser lighting. [ABSTRACT FROM AUTHOR]

Graphene microband electrodes were fabricated by direct laser writing on Kapton® polyimide tape utilizing a low-cost, blue laser (500 mW and 405 nm). The structural properties of the graphene were examined by Raman spectroscopy, and key features such as D, G, and 2D bands and the presence of multilayer structures were revealed. Scanning electron microscopy (SEM) provided insights into the microband morphology, highlighting the 3D (foam-like) nature of the graphene microbands. Electrochemical experiments revealed cyclic voltammetry profiles that demonstrated radial diffusion dominance at low scan rates and Randles–Sevcik behavior at higher scan rates. Reproducibility and repeatability analyses confirmed the stability and consistency of these microband electrodes within individual devices. Scanning electrochemical microscopy (SECM) images revealed the electrochemical reactivity of the microbands. At a relatively low microband separation (200 µm), the produced material can be collected at the adjacent microband, which was confirmed via generator/collector experiments. Theoretical–experimental comparisons regarding the current measured for a single microband were performed, and the obtained results were in good agreement, with deviations attributed to the 3D morphology of the microbands. This research underscores the potential of these cost-effective and reproducible graphene microband electrodes for diverse applications in electrochemical sensing, and we present preliminary results on caffeic acid and paracetamol detection. [ABSTRACT FROM AUTHOR]

The laser welding of magnesium alloys presents challenges attributed to their low laser-absorbing efficiency, resulting in instabilities during the welding process and substandard welding quality. Furthermore, the complexity of signals during laser welding processes makes it difficult to accurately monitor the molten state of magnesium alloys. In this study, magnesium alloys were welded using near-infrared and blue lasers. By varying the power of the near-infrared laser, the energy absorption pattern of magnesium alloys toward the composite laser was investigated. The U-Net model was employed for the segmentation of welding images to accurately extract the features of the melt pool and keyhole. Subsequently, the penetrating states were predicted using the convolutional neural network (CNN), and the novel approach employing Local Binary Pattern (LBP) features + a backpropagation (BP) neural network was applied for comparison. The extracted images achieved MPA and MIoU values of 89.54% and 81.81%, and the prediction accuracy of the model can reach up to 100%. The applicability of the two monitoring approaches in different scenarios was discussed, providing guidance for the quality of magnesium welding. [ABSTRACT FROM AUTHOR]

Objectives: Reflux hypersensitivity (RH) is a form of refractory gastroesophageal reflux disease in which duodenogastroesophageal reflux (DGER) plays a role. This study aimed to determine the usefulness of an endoscopy system equipped with image‐enhanced technology for evaluating DGER and RH. Methods: The image enhancement mode for detecting bilirubin and calculated values were defined as the Bil mode and Bil value, respectively. First, the visibility of the Bil mode was validated for a bilirubin solution and bile concentrations ranging from 0.01% to 100% (0.002–20 mg/dL). Second, visibility scores of the Bil mode, when applied to the porcine esophagus sprayed with a bilirubin solution, were compared to those of the blue laser imaging (BLI) and white light imaging (WLI) modes. Third, a clinical study was conducted to determine the correlations between esophageal Bil values and the number of nonacid reflux events (NNRE) during multichannel intraluminal impedance‐pH monitoring as well as the utility of esophageal Bil values for the differential diagnosis of RH. Results: Bilirubin solution and bile concentrations higher than 1% were visualized in red using the Bil mode. The visibility score was significantly higher with the Bil mode than with the BLI and WLI modes for 1% to 6% bilirubin solutions (P < 0.05). The esophageal Bil value and NNRE were significantly positively correlated (P = 0.031). The area under the receiver operating characteristic curve for the differential diagnosis of RH was 0.817. Conclusion: The Bil mode can detect bilirubin with high accuracy and could be used to evaluate DGER in clinical practice. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "GABAergic regulation of striatal spiny projection neurons depends upon their activity state." The correction addresses errors in Figures 3 and 4, specifically in panel E of both figures. The incorrect labeling of the inset cartoon in Figure 3E is acknowledged, and the correct labeling is provided. Additionally, in Figure 4E, the y-axis of the right panel is mislabeled and the correct labels are given. The document also provides the correct data availability statement for the paper. [Extracted from the article]

Objectives: This study assessed the effects of blue and Er:YAG lasers, fluoride varnish, and their combination on microhardness, and calcium and phosphorus content of demineralized enamel. Materials and Methods: The primary Vickers microhardness of 28 third molars was measured and their enamel calcium and phosphorous content was quantified by energy-dispersive X-ray spectroscopy. They were then randomly assigned to five groups of 5% sodium fluoride (NaF) varnish, 445nm blue laser, Er:YAG laser, 5% NaF + 445nm blue laser, and 5% NaF + Er:YAG laser. The teeth then underwent pHcycling to induce caries-like lesions. The surface microhardness of the teeth and the calcium and phosphorous content of demineralized enamel were measured again. Data were analyzed by one-way ANOVA and Tukey's test (alpha=0.05). Results: NaF, NaF-diode laser, and NaF-Er:YAG laser groups experienced a significant increase in microhardness of demineralized enamel close to the baseline value (P<0.05). The efficacy of NaF-blue laser and NaF-Er:YAG laser was higher than NaF. In blue and Er:YAG laser groups, the mean final microhardness was significantly lower than the baseline microhardness. The percentage of phosphorus in all groups was similar to that of sound enamel. The percentage of calcium in NaF group was significantly lower than that of sound enamel and all other groups. The calcium content in other groups was similar to that of sound enamel. Conclusion: Fluoride varnish had a synergistic effect with Er:YAG and blue lasers to increase the demineralized enamel microhardness; blue and Er:YAG lasers alone were less effective. [ABSTRACT FROM AUTHOR]

In recent years, an increasing number of experimental results have been published for a wide variety of systems in which high-precision, ultra-fast, and ultra-short laser pulses techniques have been used to study time-resolved dynamical processes. In the absence of a theoretical prediction of the time distribution of the transition probabilities, the lifetimes τ are generally extracted by fitting the decay time with an exponential, bi-exponential or three-exponential function. In fitting the data, the short-time behavior is generally neglected. The purpose of this study is to show that an explicit formula for the time distribution of the transition probability can be determined rigorously using time-dependent perturbation theory. A formula that perfectly fits an important subset of the experimental results from t = 0 to t = ∞ . We show that by following a route different from the usual procedure for deriving transition amplitudes and Einstein coefficients in time-dependent perturbation theory, one ends up with a time-dependent factor, that is, a temporal distribution function of the transition probabilities, and for the Einstein coefficients. The time distribution reported here looks in the time domain similar to the Planck distribution in the frequency domain. In fact, the behavior of the time distribution, with a maximum at 2 τ ln ⁡ 2 , and with τ playing the role of temperature, resembles the behavior of the Planck frequency distribution. We present several examples to demonstrate that the theoretical formula allows for easier fitting of the experimental results reported in the literature. We also show that the time distribution explains the difference in resonance heights between the experimental and theoretical blue laser spectra. [ABSTRACT FROM AUTHOR]

Objective: To determine the effect of visible blue wavelengths of argon laser beams in reducing bilirubin levels in newborns with jaundice. Background: Newborn jaundice ("hyperbilirubinemia") results from increased bilirubin concentrations in the skin and blood. Sunlight, comprising various light rays, is commonly used to treat this condition by breaking down bilirubin molecules. Other phototherapy techniques, including lamp phototherapy, are also employed. Methods: An experimental study was conducted on six male infants (5 to 15 days old) with jaundice at a hospital. These infants were exposed to blue-violet scattered light from an argon laser with a wavelength of 450 nm. Results: The concentration of bilirubin in these infants decreased following exposure to the argon laser light. The 450 nm wavelength effectively absorbs bilirubin, facilitating its breakdown. Conclusion: The study demonstrates the effectiveness of using argon laser with visible blue light in reducing bilirubin levels in infants with jaundice. This finding encourages health professionals to consider argon laser therapy as a treatment option for neonatal jaundice. [ABSTRACT FROM AUTHOR]

Leading phytopathological research is focused on managing seed-borne pathogens of rice through the utilization of engineered nanomaterials. Herein, blue laser–induced topo-morphologically nano-advanced copper salicylates (Cu-SA) (Cu/SA in 1:1 and 1:2 ratio) were prepared and evaluated for their augmented antifungal potential along seed invigoration effects in contrast to their prepared sonicated formulations. Laser disintegration on the Cu-SA (Cu/SA in 1:1 and 1:2 ratio) was achieved with high degree of success and precision using blue laser, which yielded uniformly distributed spherical nanoparticles with a narrow size distribution and better crystallinity than aqua-dispersed sonicated formulations. In vitro antifungal evaluation against seed-borne fungi of rice viz. Fusarium verticillioides and Fusarium fujikuroi revealed multiple times the augmented potential of laser-disintegrated nanoformulations (l-CuSA) than sonicated (s-CuSA) and bulk samples. Laser-induced nano-sodium bis(2-oxobenzoato)cuprate (II) (l-CuSA2) with Cu/SA in 1:2 ratio was the best to inhibit the in vitro fungal growth. Ultra-micrographs and fungal double-staining assay further rationalized the membrane disruption as the mode of action for the fungitoxicity. Nanopriming of fungal infested rice seeds with l-CuSA2 at 2500 μg/mL for 8 h showed the maximum reduction of seed rot (80.43%) and seedling blight (63.15%) with respect to control (untreated). The seed-invigorating factors of l-CuSA2 nanoprimed seeds were enhanced to maximum extent and showed the highest per cent germination (35.29%), shoot length (11.42%), root length (21.14%), dry weight (75.43%) and vigour index (81.04%) over the control. Inclusively, the seed nanopriming with l-CuSA2 proved as agro-compatible hypo-toxic semi natural nanoplatform for sustainable agriculture. [ABSTRACT FROM AUTHOR]

In clinical practice, an innovative laser technology that provides contactless preparation of soft tissues with a wavelength of 445 nm has been introduced. This study aimed to investigate the morphological changes in the oral mucosa when exposed to laser radiation at a wavelength of 445 nm in the ablation mode. An experimental study was conducted to analyze the dynamics of reparative regeneration in the wound caused by that particular type of radiation, utilizing the procedure of lower lip frenuloplasty as an illustration. 48 sexually mature male laboratory rats were chosen as the research object. The procedure of preparing the oral vestibule was executed by employing a contactless laser beam with a wavelength of 445 nm and a power of 0.7 W in continuous mode (CW) and an uninitiated fiber. Histological examination showed that 25 min after the surgery, there were large areas of coagulation necrosis in the oral mucosa in the area affected by the blue laser. In 48 h, the area of necrosis decreased both in size and depth. By the 7th day after the surgery, the necrotic masses had grown into the connective tissue, while marginal regeneration of the epithelium was noted. By the 14th day, the wound surface was completely epithelialized, represented by fibrous scar tissue. Clinically, around the mandibular incisors, there was a wide area of attached keratinized gingiva. The findings of histological examination indicate a necrosis of coagulation type in the region of tissue ablation and also show the absence of phase II of the inflammatory response (the stage of exudation), which expedites the process of epithelialization of the oral mucosa wound. [ABSTRACT FROM AUTHOR]

Objectives: The Japan NBI Expert Team (JNET) classification has good diagnostic potential for colorectal diseases. We aimed to explore the diagnostic value of the JNET classification type 2B (JNET2B) criteria for colorectal laterally spreading tumors (LSTs) based on magnifying endoscopy with blue laser imaging (ME‐BLI) examination. Methods: Between January 2017 and June 2023, 218 patients who were diagnosed as having JNET2B‐type LSTs using ME‐BLI were included retrospectively. Endoscopic images were reinterpreted to categorize the LSTs as JNET2B‐low (n = 178) and JNET2B‐high (n = 53) LSTs. The JNET2B‐low and JNET2B‐high LSTs were compared based on their histopathological and morphological classifications. Results: Among the 178 JNET2B‐low LSTs, 86 (48.3%) were histopathologically classified as low‐grade intraepithelial neoplasia, 54 (30.3%) as high‐grade intraepithelial neoplasia (HGIN), 37 (20.8%) as intramucosal carcinoma (IMC), and one (0.6%) as superficial invasive submucosal carcinoma (SMC1). Among the 53 JNET2B‐high LSTs, five (9.4%) were classified as HGIN, 28 (52.9%) as IMC, 15 (28.3%) as SMC1, and 5 (9.4%) as deep invasive submucosal carcinoma. There were significant differences in this histopathological classification between the two groups (P < 0.001). However, there was no significant difference between JNET2B‐low and JNET2B‐high LSTs based on their morphological classification (granular vs nongranular) or size (<20 mm vs ≥20 mm). Besides, the κ value for JNET2B subtyping was 0.698 (95% confidence interval 0.592–0.804) between the two endoscopists who reassessed the endoscopic images. Conclusion: The JNET2B subtyping of LSTs has a diagnostic potential in the preoperative setting, and may be valuable for treatment decision‐making. [ABSTRACT FROM AUTHOR]

Electron leakage currents seriously hinder GaN-based blue laser diodes (LDs) from high wall-plug efficiencies. Inserting an ultra-thin AlGaN electron blocking layer (EBL) in the epitaxy structure is a major technique to suppress the leakage currents for which a high Al composition in the EBL is necessary. Despite many studies on the optimization of the compositions of EBLs, it is questionable whether they reach the designed value in real growths by metal-organic vapor phase epitaxy. We investigate the influence of the growth conditions of upper cladding layers (CLs) on the underlying EBLs. A strong composition degradation of the EBL is observed when the growth rate of the CL is low, which drastically reduces the output performance of both LEDs and LDs. A 30-nm fast-growing protecting layer can efficiently prevent the EBL from such degradation. The phenomenon cannot be explained by a composition pulling effect nor an etch effect by hydrogen, but by a mutual solid solution between the EBL and the adjacent CL. The solution process is found thermally favored by calculating the Gibbs energy where strain and entropies are considered. It is inferred that the chemically active Ga adatoms at the surface play an important role in accelerating the solution process. Based on these considerations, we introduce a random walk model to clarify the kinetic influence of CL growth rates on EBL degradation semi-quantitatively. The results help to understand the subtle process in the growth of heterostructures and the transport process of GaN-based LDs. [ABSTRACT FROM AUTHOR]

A fifteen-year-old boy appeared at my clinic with impaired vision in his left eye to 20/70 following a brief exposure to a high power class IVb blue laser pointer. A mirror at a distance of one meter reflected the beam for two seconds onto his left eye. He reported having a left eye with a central black spot and a blurry vision. A sub-internal limiting membrane (ILM) haemorrhage near the fovea was discovered during a fundus examination. of the left eye was identified as a red, well-circumscribed patch in the foveal area. The optical coherence tomography (OCT) scan verified the existence of bleeding beneath the ILM layer. The central fovea of the left eye's fluorescein angiography showed a little early transmission deficiency without late staining. A relative central scotoma was discovered by perimetry in the left eye. Both eyes' anterior segments appeared normal. The fundus examination of the right eye revealed normal results. The haemorrhage was completely cured and the visual acuity recovered to 20/20 seven weeks later. These devices need to be properly warned of, and children shouldn't have unlimited access to them. [ABSTRACT FROM AUTHOR]

The need to manufacture components out of copper is significantly increasing, particularly in the solar technology, semiconductor, and electric vehicle sectors. In the past few decades, infrared laser (IR) and green laser (GL) have been the primary technologies used to address this demand, especially for small or thin components. However, with the increased demand for energy saving, alternative joint techniques such as blue diode laser (BDL) are being actively explored. In this paper, bead-on-plate welding experiments on 0.2 mm thick pure copper samples employing a BDL are presented. Two sets of parameters were carefully selected in this investigation, namely Cu-1: Power (P) = 200 W; Speed (s) = 1 mm/s; and angle = 0°, and Cu-2: P = 200 W; s = 5 mm/s; and angle = 10°. The results from both sets of parameters produced defect-free full penetration welds. Hardness test results indicated relatively softer weld zones compared with the base metal. Tensile test samples fractured in the weld zones. Overall, the samples welded with Cu-1 parameters showed better mechanical properties, such as strength and elongation, than those welded with the Cu-2 parameters. The tensile strength and elongation obtained from Cu-1 were marginally lower than those of the unwelded pure copper. The outcomes from this research provide an alternative welding technique that is able to produce reliable, strong, and precise joints, particularly for small and thin components, which can be very challenging to produce. [ABSTRACT FROM AUTHOR]

Natural products derived from plants can be used as photosensitizers for antimicrobial photodynamic therapy (aPDT) combining key therapeutic strategies for tissue repair while controlling microorganisms' growth. We investigated a standardized extract of pequi peels (Caryocar brasiliense Cambess) as a brownish natural photosensitizer for aPDT using blue light. Three concentrations of the pequi extract (PE; 10, 30, or 90 μg/mL) were tested solely or associated with blue laser (445 nm, 100 mW, 138 J/cm2, 6 J, 60 s). In vitro, we quantified reactive oxygen species (ROS), assessed skin keratinocytes (HaCat) viability and migration, and aPDT antimicrobial activity on Streptococcus or Staphylococcus strains. In vivo, we assessed wound closure for the most active concentration disclosed by the in vitro assay (30 μg/mL). Upon aPDT treatments, ROS were significantly increased in cell monolayers regardless of PE concentration. PE at low doses stimulates epithelial cells. Although PE stimulated cellular migration, aPDT was moderately cytotoxic to skin keratinocytes, particularly at the highest concentration. The antimicrobial activity was observed for PE at the lowest concentration (10 μg/mL) and mostly at PE 10 μg/mL and 30 μg/mL when used as aPDT photosensitizers. aPDT with PE 30 μg/mL presents antimicrobial activity without compromising the initial phases of skin repair. [ABSTRACT FROM AUTHOR]

The suppression of laser speckle has always been a crucial research topic in the field of laser display. At present, many methods of laser speckle suppression have been proposed. In this paper, we present a method for reducing speckle in high‐frequency current driven RGB semiconductor lasers. The RGB monochromatic speckle contrast in direct current (DC) driving mode and 100 Hz to 50 MHz pulse modulation frequency driving mode, and the color luminosity speckle contrast of composite light in 1 KHz to 45 MHz pulse modulation frequency driving mode were measured. Red laser speckle contrast is reduced from 47.12% to 38.5%, Green laser speckle contrast is reduced from 35.69% to 21%, and blue laser speckle contrast is reduced from 31.5% to 25.09%. Additionally, the photometric speckle contrast of composite light decreased by approximately 6%. Experimental results demonstrate that high‐frequency current driving mode disrupts the coherence of lasers and effectively suppresses both monochromatic and color‐based laser speckles. [ABSTRACT FROM AUTHOR]

Laser beam welding as a reliable tool for high-precision joining of batteries or microelectronics is more and more the choice for achieving reproducible results in production processes. In addition to a high automation capability, the precise control of the energy deposition into the material plays an important role, especially when highly reflective materials, such as copper or aluminum, must be welded together. Alongside the use of highly brilliant fiber lasers in the near-infrared range with a focal diameter of a few tens of micrometers, diode lasers in the wavelength range of 445 nm are increasingly being used. Here, beam diameters of a few hundred micrometers can be achieved. With a wavelength of 445 nm, the absorptivity in copper can be increased by more than a factor of 10 compared to a near-infrared laser beam sources in solid state at room temperature. This paper presents the in situ X-ray observation of laser welding processes on CuSn6 with a laser beam source with a wavelength of 445 nm using synchrotron radiation at DESY Petra III Beamline P07 EH4 in Hamburg, Germany. For the experiments, the laser radiation was focused via two separate optics to focal diameters of 362 µm and 609 µm. To characterize the dynamics of the vapor capillaries depending on the different focal diameters dF, the parameters were varied with respect to laser power PL and feed rate v. For the investigations, a synchrotron beam of 2 × 2 mm2 in size with a photon energy of 89 keV was used, and the material samples were analyzed by means of phase-contrast videography to show the boundaries between solid, liquid, and gaseous material phases. The results of this paper show the welding depths achieved and how the geometry of the vapor capillary behaves by changing the focal diameter, laser power and feed rate. [ABSTRACT FROM AUTHOR]

Controlling chemical processes in live cells is a challenging task. The spatial heterogeneity of biochemical reactions in cells is often overlooked by conventional means of incubating cells with desired chemicals. A comprehensive understanding of spatially diverse biochemical processes requires precise control over molecular activities at the subcellular level. Herein, a closed‐loop optoelectronic control system is developed that allows the manipulation of biomolecular activities in live cells at high spatiotemporal precision. Chemical‐selective fluorescence signals are utilized to command lasers that trigger specific chemical processes or control the activation of photoswitchable inhibitors at desired targets. This technology is fully compatible with laser scanning confocal fluorescence microscopes. The authors demonstrate selective interactions of a 405 nm laser with targeted organelles and simultaneous monitoring of cell responses by fluorescent protein signals. Notably, blue laser interaction with the endoplasmic reticulum leads to a more pronounced reduction in cytosolic green fluorescent protein signals in comparison to that with nuclei and lipid droplets. Moreover, when combined with a photoswitchable inhibitor, microtubule polymerization is selectively inhibited within the subcellular compartments. This technology enables subcellular spatiotemporal optical manipulation over chemical processes and drug activities, exclusively at desired targets, while minimizing undesired effects on non‐targeted locations. [ABSTRACT FROM AUTHOR]

Background: The management of glomus tympanicum tumours can be challenging. Blue laser coagulation may improve bleeding control thus facilitating an endoscopic transcanal excision. The objective of this presentation is to illustrate the authors' experience using this novel tool. Methods: Case report of a patient that underwent exclusive endoscopic transcanal blue laser surgery of a class A2 glomus tympanicum tumour in a tertiary referral center. Conclusion: The present study provides evidence of the safety and efficacy of endoscopic blue laser surgery, for the minimally invasive treatment of early-stage glomus tympanicum tumours. [ABSTRACT FROM AUTHOR]

Purpose: To report the efficacy of blue laser in the treatment of vocal fold polyps and Reinke's edema in an office setting. Methods: The medical records and video-recordings of patients who underwent office-based blue laser therapy in a tertiary referral center for vocal fold polyps and/or Reinke's edema were reviewed. The primary outcome measures were the Voice Handicap Index-10 (VHI-10) score and disease regression. Acoustic and aerodynamic parameters were also analyzed. Results: Thirty-five patients (21 with vocal fold polyps and 14 with Reinke's edema) were included and a total of 47 lesions were treated. Out of the 35 patients, 7 patients were lost for follow-up. The mean VHI-10 score dropped significantly after surgery by 17.41 ± 8.67 points (p < 0.001). The endoscopic examinations of 38 lesions were reviewed (17 vocal fold polyps and 21 Reinke's edema) before and up to 6 months after laser therapy. In the subgroup with vocal fold polyps (N = 17), there was complete disease regression in 13 and partial in 4. In the subgroup with Reinke's edema (N = 21), there was complete disease regression in 7 and partial disease regression in 14. For patients with vocal fold polyp, there was a significant decrease in shimmer and a significant increase in maximum phonation time postoperatively. For patients with Reinke's edema, there was a significant decrease in shimmer and noise-to-harmonic ratio following treatment. Conclusion: Office-based blue laser therapy is an effective treatment for vocal fold polyps and Reinke's edema leading to complete or partial disease regression. All patients had improvement in voice quality. [ABSTRACT FROM AUTHOR]

Blue diode lasers are alternative curing devices for dental composites. The aim of this study was to investigate the influence of blue diode laser polymerization on shear bond strength of bulk fill composites to human dentin and temperature rise during two types of polymerization. Composite cylinders of SDR Plus(SDR) and Ever X Flow(EX) were bonded to dentin slabs using Adhese Universal and curing devices blue diode laser (449 nm, 1.6 W) and Power Cure LED. For each material and curing device there were two polymerization approaches: 1)conventional: separate curing of adhesive; 2)co-curing: simultaneous adhesive and composite curing. Polymerization modes for each material in conventional and co-curing(c) approach were: blue laser 2000 mW/cm2 for 5 s (L5 and L5c); blue laser 1000 mW/cm2 for 10 s (L10 and L10c); Power Cure 2000 mW/cm2 for 5 s (LED5 and LED5c); Power Cure 1000 mW/cm2 for 10 s (LED10 and LED10c). Temeperature was measured using thermal vision camera. For SDR, the highest bond strength was 24.3 MPa in L10c, and the lowest 9.2 MPa in LED5c. EX exhibited the highest bond strength(21.3 MPa) in LED5, and the lowest in L5(7.7 MPa). The highest temperature rise for SDR was in L10 and L5 (7.3 and 7.2 °C), and the lowest in LED5(0.8 °C). For EX, the highest temperature rise was in L5 (13.0 °C), and the lowest in LED5 (0.7 °C). Temperature rise was higher during blue laser polymerization, especially at high intensity and with conventional curing. Preferable blue laser curing mode is co-curing at 1000mW/cm2 for 10 s. [ABSTRACT FROM AUTHOR]

Introduction: Crown lengthening is a reliable procedure that enables the restoration of teeth with a short clinical crown, extensive subgingival caries, and correction of excessive gingival display for aesthetic purposes. Blue laser, a recent technology in dentistry, has shown significant effectiveness at low power settings, promoting favourable wound healing effects. Aim: To compare the Visual Analogue Scale (VAS) scores and wound healing outcomes between blue laser and denlase in performing crown lengthening procedures. Materials and Methods: A randomised clinical trial was conducted in the Department of Periodontics and Implantology, Vishnu Dental College, Bhimavaram, Andhra Pradesh, India, involving 14 patients who were divided into two groups. Participants were recruited from September 2021 to April 2022. Ethical clearance was obtained from the Institutional Ethics and Review Board. Group-A underwent crown lengthening using blue laser (445 nm), while Group-B received treatment with denlase (980 nm). VAS scores and the wound healing index were recorded and compared between the two groups at baseline, 10 days, and one month after the surgery. Statistical tests such as the Mann-Whitney U test, unpaired t-test, and repeated measures ANOVA were used for analysis. Results: The study revealed a statistically significant difference (p-value=0.006) in VAS scores between the blue laser group (mean value of 0.5) and the denlase group (mean value of 1.3). However, statistically significant differences in Wachtel's early wound healing index were not observed in either of the groups. Conclusion: Blue laser treatment was found to be more comfortable for patients, as indicated by the lower VAS scores. Both groups demonstrated good wound healing properties based on Wachtel's early wound healing index, with no significant difference between them. It is important to note that literature on blue laser technology is still in its early stages and requires further comprehensive investigation. [ABSTRACT FROM AUTHOR]

Background: The main therapeutic modality of early upper gastrointestinal neoplasms has shifted from surgery to endoscopic therapy. The role of endoscopy has also expanded not only for more accurate diagnosis of neoplasms but also for the determination of extent and depth of neoplasms with a combination of multiple electronically modified images acquired with image-enhanced endoscopy (IEE) for assessing the feasibility of endoscopic treatment. Summary: These IEE with or without magnifying endoscopy including narrow-band imaging, blue laser imaging, and linked color imaging (LCI) using narrow-band light have greatly changed the diagnosis for upper gastrointestinal neoplasms. These modalities produce high color contrast between cancer and surrounding mucosa at distant views and clear visualization of surface and vessels at close-up observations. LCI shows purple color of intestinal metaplasia (IM) distinct from other inflammatory gastric mucosae and facilitates the recognition of early gastric cancers often surrounded by IM. Recently, ultrathin endoscopy has provided high-resolution images similar to standard-caliber endoscopy. In addition, these advanced IEEs that integrate computer-assisted artificial intelligence systems are marked and will improve our diagnostic performance for neoplasia in the future. Key Message: New IEE with sufficient brightness and color contrast has increasingly been used based on accumulated evidence for early and accurate detection of neoplastic lesions. We provide recent articles relevant to endoscopic diagnosis with IEE on esophageal, gastric, and duodenal neoplasms. Endoscopic equipment that integrates artificial intelligence support system is now being introduced into routine clinical use and is expected to enhance early detection of neoplastic lesions. [ABSTRACT FROM AUTHOR]

The development of sustainable alternatives to chemical and mechanical biofilm removal for submerged technical devices used in freshwater and marine environments represents a major technical challenge. In this context, the antibiotic impact of blue light with its low absorption underwater provides a potentially useful alternative. However, former technical limitations led to hours of treatment. Here, we applied high-power blue laser irradiation (1500 W) with a wavelength of 448 nm to demonstrate its strong antibiotic and algicidal effect on different bacteria and algae in seconds. High-power blue light treatment (139 W/cm2) for only 8.9 s led to the efficient deactivation of all tested organisms. Analyses of the underlying biological mechanisms revealed the absorption of the blue light by endogenous chromophores (flavins, tetrapyrroles) with the generation of reactive oxygen species (ROS). In agreement, Escherichia coli transcriptome analyses demonstrated a stress response at the level of DNA damage repair, respiration, and protein biosynthesis. Spectroscopic measurements of the irradiated algae indicated the irreversible damage of chlorophyll by photooxidation with the formation of singlet oxygen. In conclusion, high-power blue laser radiation provides a strong sustainable tool for the removal of biofouling in a very short time for applications in aquatic systems. [ABSTRACT FROM AUTHOR]

The findings of the study demonstrate the impact of low-intensity laser and quasi-monochromatic light on the biosynthetic activity of the edible medicinal fungus L. edodes during submerged cultivation. An artificial lighting installation based on matrices of light-emitting diodes (LED) emitting light at 470 nm (blue), 530 nm (green), 650 nm (red), and argon gas laser (488 nm) was used. Irradiation with blue and red LED and laser led to a shortening of the lag phase by 2 days and an increase in the mycelial mass. Irradiation with laser light resulted in the highest mycelial mass yield (14.1 g/L) on the 8th day of cultivation. Irradiation in all used wavelength ranges caused an increase in the synthesis of both extracellular and intracellular polysaccharides. Laser light at 488 nm and LED at 470 nm proved to be the most effective. Irradiation with red, green, and blue laser light caused an increase in the total amount of fatty acids in the mycelial mass compared to the control. A significant distinction in qualitative composition was observed: short-chain acids C6‒C12 compounds were produced under red light irradiation, whereas long-chain C20‒C24 were formed under green light irradiation. The most significant changes in the aromatic profile of the mycelial mass and culture liquid were recorded upon irradiation with green light. The content of aromatic components increased 24.6 times in the mycelial mass and 38.5 times in the culture liquid. The results suggest the possibility of using low-intensity quasi-monochromatic light for targeted regulation of L. edodes biosynthetic activity. [ABSTRACT FROM AUTHOR]