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Conductive polymers such as PEDOT:PSS undergo complex structural and electronic changes under external stimuli, yet their state evolution under sequential thermal and hydration processes remains poorly understood. Here, we investigate laser-water interactions in PEDOT:PSS from the perspective of material state evolution and relaxation rather than simple modification and erasure. Using a mechanically interlocked PEDOT:PSS configuration that remains stable under repeated laser irradiation and hydration, we systematically examine how laser-defined material states evolve upon subsequent water exposure. Continuous-wave laser irradiation induces a distinct non-carbonized blue optical transition that is clearly distinguishable from irreversible carbonization. Upon water exposure, this laser-defined state exhibits reversible optical and morphological changes, while the extent of relaxation strongly depends on the prior laser irradiation conditions. Correlative analyses of surface and internal morphology, molecular structure, and electrical response reveal that hydration-driven relaxation does not necessarily restore the pristine state but instead proceeds along pathways determined by the laser-induced configuration. These findings demonstrate that water acts as an active mediator of state relaxation rather than a simple reset mechanism. This work provides a framework for understanding history-dependent state evolution in hydration-sensitive conductive polymers under sequential laser and environmental stimuli.
This review presents a comprehensive analysis of the physicochemical mechanisms underlying surface engineering of Cu-Zn alloys through femtosecond laser processing. It focuses on the coupled evolution of laser-induced plasma formation, selective ablation, nonequilibrium Zn redistribution, and plasma-assisted oxidation. Experimental and theoretical evidence indicates that ZnO formation cannot be explained by gas-phase reactions or surface oxidation alone, but results from the interplay of plasma processes, diffusion-controlled Zn redistribution, and heterogeneous oxidation under nonequilibrium conditions. A plasma-surface-diffusion framework is employed to interpret these coupled processes, linking selective Zn redistribution, plasma-assisted oxidation, and ZnO formation within the laser-modified surface layer. The review discusses ZnO evolution, including the influence of supersaturation, defects, and relaxation times, and highlights the effects of laser-induced structuring on reaction kinetics, energy redistribution, and mass transport. Comparison with plasma-assisted and gas-phase ZnO synthesis demonstrates common kinetic stages while emphasizing the localized and transient nature of femtosecond laser processing. This integrated interpretation provides a mechanistic basis for controlled ZnO formation. Overall, ZnO formation on Cu-Zn alloys is interpreted through a multiscale physicochemical approach integrating nonequilibrium electron excitation, plasma evolution, Zn redistribution, heterogeneous oxidation, and surface morphology, providing a framework for the rational optimization of laser-functionalized brass surfaces.
This study presents an Artificial Neural Network (ANN) approach for predicting laser-induced material modifications during femtosecond laser micromachining of aluminum. Experimental investigations were carried out to determine the influence of the average laser power and scanning speed on the width of the ablation groove and the size of the optically determined surface-discoloration width used as a proxy for the Heat-Affected Zone (HAZ). The collected dataset, consisting of 100 samples, was used to develop, train, validate, and test an ANN predictive model with two inputs, two outputs, and two hidden layers. Despite its simplicity and the relatively small dataset, the developed model achieved relatively good prediction accuracy, with an overall correlation coefficient (R) of approximately 0.95 on the test dataset. The predicted values showed reasonable agreement with the experimental results, indicating that the ANN approximated the relationship between laser processing parameters and the resulting material modifications. The presented methodology may provide a useful tool for predicting surface morphology changes and thermal effects in femtosecond laser processing of aluminum.
Background/Objectives: Orthodontic mini-implants have become an essential source of temporary skeletal anchorage because of their versatility, minimal invasiveness, and reduced dependence on patient compliance. However, their clinical success relies on maintaining adequate primary and secondary stability throughout orthodontic treatment. Photobiomodulation (PBM) with diode lasers has been proposed as a non-invasive adjunctive therapy capable of enhancing bone healing and remodeling, thereby improving mini-implant stability. Despite encouraging findings, the available evidence remains limited and heterogeneous. The objective was to systematically evaluate the effect of diode laser photobiomodulation on the stability of orthodontic mini-implants. Methods: A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The search was conducted in the PubMed, EBSCO, Scopus, and ScienceDirect databases to identify randomized clinical trials published in the last 10 years. Five randomized controlled trials involving 89 participants and 178 orthodontic mini-implants fulfilled the eligibility criteria. Mini-implant stability was assessed using objective methods, including resonance frequency analysis (ISQ) and Periotest values, while one study also evaluated insertion and removal torque. The methodological quality of the included studies was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool, and the certainty of the evidence was evaluated using the GRADE approach. Results: Three of the five included studies reported improvements in orthodontic mini-implant stability following diode laser photobiomodulation, whereas two studies found no significant differences compared with the control group. Considerable heterogeneity was identified regarding laser wavelength (618-940 nm), irradiation protocols, energy parameters, timing of force application, and stability assessment methods. Most studies presented a low risk of bias, although some concerns remained regarding allocation concealment and blinding. According to the GRADE assessment, the overall certainty of the evidence was considered moderate, mainly because of inconsistency across studies and methodological heterogeneity. Conclusions: Current evidence suggests that diode laser photobiomodulation may improve the stability of orthodontic mini-implants. Nevertheless, the small number of randomized clinical trials and the substantial variability in PBM protocols and outcome assessment methods preclude definitive clinical recommendations. Future well-designed randomized controlled trials using standardized irradiation parameters and uniform stability assessment methods are required to establish evidence-based clinical protocols.
Here we introduce the Electrospray Laser Venturi Ionization Sampling (ELVIS) probe, a handheld ambient sampling device that combines desorption performed by a simple laser pointer with Venturi-assisted plume transport for remote mass spectrometric analysis. The ELVIS probe is portable, inexpensive, easy to operate and to point to a target area and exhibits no detectable carryovers. The probe can also be readily coupled to most atmospheric-pressure ionization sources, as demonstrated herein for electrospray ionization (ESI). The ELVIS probe employs Venturi pumping to provide efficient and controllable aspiration of the laser-generated plume. This mechanism transports analyte vapors directly to the ion source, substantially reducing signal dispersion that commonly occurs during open-air sampling or when carrier gases are used. Desorption is achieved using a compact, low-cost, yet highly effective 0.5 W laser pointer, enabling the sampling of a wide range of analytes from diverse matrices. Notably, the ELVIS probe is particularly advantageous for sampling target analytes deeply embedded within complex matrices, where spray-based or liquid-extraction ambient MS techniques often fail. For proper ionization, the probe was coupled to a commercial ESI source and successfully applied to the detection of illicit drugs, plasticizers in PVC, caffeine directly from a coffee bean, and pesticide residues on the wings of a deceased honeybee. The advantageous coupling of the ELVIS probe with Venturi-assisted easy ambient sonic-spray ionization is also discussed.
A widely tunable narrow-linewidth continuous-wave (CW) mid-infrared (MIR) laser was realized with a PPMgO:LN-based optical parametric oscillator (OPO) pumped by a 1060 nm single-frequency fiber laser. The MIR laser tuning with a range from 2250.7 to 5092.7 nm was obtained using the two multi-period PPMgO:LN crystals. The output power was larger than 520 mW@2250.7-4000 nm, 160 mW@4000-4300 nm, and 15 mW@4300-5095.4 nm, where the maximum output power of 4.64 W@2500 nm was obtained with an optical-to-optical conversion efficiency of 15.5%. The linewidth was measured to be ~0.41 MHz at 3300 nm using the delayed self-homodyne method. The output power stability was measured to be RMS = 1.43% for 8 h. The beam quality factors at 2786, 3360, and 4453 nm were 1.18, 1.19, and 1.26, measured using the knife-edge method. Finally, an engineering prototype was developed using high-reliability engineering design and system integration. Our results will play a significant role in the development of widely tunable narrow-linewidth MIR lasers.
Laser frequency stabilization underpins precision metrology, optical atomic clocks, quantum optics, and laser spectroscopy. In recent years, field-programmable gate arrays (FPGAs) have become attractive for this task because signal generation, phase-sensitive detection, digital filtering, feedback control, lock monitoring, and automatic re-locking can be integrated on compact and reconfigurable platforms. This review examines recent progress in FPGA-based laser frequency stabilization from four linked perspectives: stabilization principles, digital implementation, system architecture, and intelligent control. We first summarize representative error-signal generation methods, including Pound-Drever-Hall locking, saturation absorption spectroscopy, frequency modulation spectroscopy, and modulation transfer spectroscopy. We then discuss the FPGA functions that determine practical performance, such as data acquisition, direct digital synthesis, digital demodulation, proportional-integral-derivative (PID)/infinite impulse response (IIR) filtering, latency management, and lock-state monitoring. Mixed-signal, all-digital, distributed, and machine-learning-assisted systems are compared to show how bandwidth, latency, stability, integration, cost, and automation are balanced in different designs. This review closes by identifying remaining challenges in analog-to-digital converter/digital-to-analog converter (ADC/DAC) resolution, converter noise, loop latency, actuator bandwidth, long-term robustness, and algorithm portability, and by outlining future directions toward low-latency, software-defined, and intelligent stabilization platforms.
We demonstrate an integrated eight-wavelength high-power laser source on a 4H-silicon carbide (SiC)-based optical integration platform. Eight discrete Fabry-Perot laser diodes emitting at 445 nm, 637 nm, 789 nm, 806 nm, 846 nm, 978 nm, 1316 nm, and 1552 nm are integrated on a single SiC chip, each delivering ≥100 mW continuous-wave output power. A complete fabrication process is developed, including lift-off metallization (Ni/Ti/Pt/Au), surface hydrophilic activation bonding, and multi-step blade dicing to form SiC waveguides with a width of 500 μm and a thickness defined by the ~510 μm dicing depth, matching the output aperture of the multimode laser diodes. The resulting waveguides exhibit a facet misorientation of <1° and an approximate facet mean surface roughness of ~2 nm. The laser diodes are directly butted against the waveguide facets for edge coupling, and fixed using In52Sn48 solder bonding with pulse temperature control. Under controlled temperature, all eight channels operate stably with measured peak wavelengths matching the design targets. This work provides a scalable and practical solution for multi-wavelength, high-power on-chip light source integration on the SiC platform, addressing critical thermal and integration challenges for dense wavelength division multiplexing.
Dorsal metacarpal disease (DMD) is a common musculoskeletal injury in young racehorses, and effective non-invasive treatments remain of clinical interest. This study aimed to evaluate whether high-intensity laser therapy (HILT), which was applied as the sole intervention in horses retired from training, reduces the clinical signs of DMD compared with untreated controls. During the 2023-2024 racing seasons, 15 Arabian racehorses diagnosed with DMD were enrolled; 9 received HILT and 6 served as controls without laser therapy. The treatment protocol consisted of five daily HILT sessions followed by five sessions administered every other day. Thermographic, orthopedic, and radiographic examinations of the third metacarpal bones were performed before and after the treatment period in both groups, with additional thermographic and clinical assessments conducted throughout therapy. The results showed that horses treated with HILT did not exhibit a significant reduction in pain and lameness accompanied by thermographic changes consistent with decreased inflammation. These findings indicate that HILT did not alleviate clinical signs associated with DMD in the affected horses; however, further controlled studies are required to determine its effect on tissue healing processes and to optimize treatment duration.
Spatial multi-omics analyzes biomolecules such as the proteome, metabolome, and lipidome within their native spatial context in tissues or cells. Mass spectrometry imaging (MSI) has emerged as a powerful technique for mapping the region-specific molecular distribution in regions of interest (ROIs). Laser capture microdissection coupled with mass spectrometry (LCM-MS) is another well-established workflow, enabling the accurate characterization of biomolecules in ROIs. To advance the current analytical application, we expanded a matrix-assisted laser desorption/ionization (MALDI)-MSI-guided LCM-MS workflow for integrated multi-omics analysis and applied it to mouse brain tissue as a proof-of-principle validation. MALDI-MSI annotated 387 putative metabolites and lipids, revealing distinct molecular distributions between the cortex and hippocampus. Both regions were subsequently isolated as ROIs using LCM and analyzed by LC-MS/MS metabolomics, lipidomics, and proteomics to achieve accurate biomolecular profiling. LC-MS/MS metabolomics and lipidomics annotated 249 compounds, several of which exhibited distinct abundance patterns between the two regions. LC-MS/MS proteomics matched to over 3500 protein groups across the two regions. Biological network analysis revealed strong associations between molecular pathways and known region-specific phenotypes. Overall, this MALDI-MSI-guided LCM-MS workflow enables comprehensive spatial multi-omics profiling and quantitative biomolecular analysis, providing valuable insights into complex biological systems and spatial molecular organization.
Traditional methods for wine bottle packaging leakage detection often suffer from low efficiency, high false-positive rates, or an inability to detect micro-leakages. This paper proposes a near-infrared laser leakage detection system based on tunable diode laser absorption spectroscopy at 1392 nm, combined with a LightGBM machine learning model. The system detects gaseous ethanol vapor escaping from leaking bottles, addressing the spectral interference caused by ambient water vapor. A total of 1410 samples were collected, and each raw 2000-point spectral contour was compressed into a 200-dimensional feature vector through baseline correction, Z-score normalization, and uniform down-sampling. A two-stage hyperparameter optimization strategy yielded the optimal LightGBM configuration with a 5-fold cross-validation. For the binary classification task, the model achieved an AUC of 0.9949 and an inference speed of 0.0058 ms per sample on a CPU, outperforming Random Forest, PLS, and four deep learning models. For the regression task, the model achieved an R2 of 0.5854 ± 0.0919. An anti-interference experiment on 422 samples under varying flow rates, temperatures, and commercial wine types confirmed the model's robustness, achieving an overall accuracy of 0.94 and an alcohol recall of 0.99. To further validate the system under realistic conditions, a simulated micro-leakage test was conducted using a negative-pressure extraction method: 320 samples were collected from artificially damaged commercial wine bottles placed in a custom-built acrylic vacuum chamber that replicates the production line enclosure. The model achieved an accuracy of 0.95 with zero false negatives. The complete detection cycle takes no more than 5 s per bottle, enabling non-destructive, rapid, and online packaging integrity assessment. The results demonstrate that the proposed system provides a low-cost and reliable solution for wine bottle leakage detection suitable for industrial deployment.
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has become a valuable tool for molecular mapping in neurological disorders. This scoping review synthesized current evidence on its use in proteomic analysis of neural tissues in Alzheimer's disease (AD). From 1,419 screened records, 26 studies met the inclusion criteria. Findings highlight MALDI-MS's capacity to detect beta-amyloid (Aβ) proteoforms, and tau protein post-translational modifications linked to AD. Its high spatial resolution enables region-specific molecular profiling, enhancing understanding of AD pathophysiology and supporting early biomarker discovery. The review underscores the translational potential of MALDI-MS in advancing targeted therapeutic development. A espectrometria de massas por dessorção/ionização a laser assistida por matriz (MALDI-MS) tornou-se uma ferramenta valiosa para o mapeamento molecular em distúrbios neurológicos. Esta revisão de escopo sintetizou as evidências atuais sobre seu uso na análise proteômica de tecidos neurais na doença de Alzheimer (DA). De 1.419 registros triados, 26 estudos atenderam aos critérios de inclusão. Os achados destacam a capacidade da MALDI-MS para detectar protoformas de beta-amiloide (Aβ) e modificações pós-traducionais da proteína tau associadas à DA. Sua alta resolução espacial possibilita o perfil molecular específico por região, ampliando a compreensão da fisiopatologia da DA e apoiando a descoberta precoce de biomarcadores. A revisão ressalta o potencial translacional da MALDI-MS no avanço do desenvolvimento de terapias direcionadas.
The considerable expense associated with metal additive manufacturing (AM), partly attributed to the high costs of raw materials, forms a significant obstacle hindering the widespread adoption and scaling of this technology. In response to this challenge, this study endeavors to explore and optimize the laser powder bed fusion (LPBF) process parameters for Ti-6Al-4V powders with offsize (45-106 µm) and wide (15-106 µm) particle size distribution (PSD) which are more cost-effective. The outcomes will be compared to those of the same alloy with a standard 15-53 µm PSD. The primary focus of this investigation revolves around two key objectives: firstly, establishing correlations between the laser powder bed fusion process parameters and the resulting density, hardness, and roughness. This objective is achieved by investigating the impact of process parameters within the context of the contour-skin-core method. Secondly, the porosity, microstructure, elemental composition, and dimensional fidelity of several components made from the offsize and wide powders were investigated, utilizing the optimized process parameters for density. To this end, an efficient multi-step experimental design and optimization process was adopted. The findings resulted in the identification of correlations between the significant process parameters and the studied responses, enabling the achievement of 98.7% density and 40.6 HRC hardness for offsize powder and 98.7% density and 40 HRC hardness for wide powder. A separate set of optimized process parameters for larger geometries produced densities exceeding 99.9% in both as-built and HIP conditions across all three powders. Additionally, the results confirmed the higher sensitivity of the roughness to powder size, with the optimized values fluctuating between 9.5 µm and 15.7 µm. Comprehensive microstructural investigation reveals no significant differences in phase evolution or grain structure resulting from the use of offsize or wide powders. This study confirms the viability of utilizing powders containing a higher portion of large particles to mitigate the costs associated with LPBF processes.
Silicon carbide (SiC) has high thermal conductivity and thermal stability; however, its high hardness and brittleness make the fabrication of three-dimensional (3D) SiC microstructures-particularly those intended for thermal management of power devices-highly challenging. Because SiC exhibits strong absorption in the ultraviolet (UV) spectral range, this study conducted UV nanosecond laser irradiation to perform dry, direct-write processing on SiC, with material removal achieved through vaporization. It established an optimization workflow covering processes from the selection of planar processing parameters to the fabrication of 3D micropillar arrays with high surface quality and geometric fidelity. The key process variables were the pulse repetition frequency, nominal laser power, number of repeated scans per layer, and number of Z-direction focal shifts between layers. The micropillar arrays fabricated using the proposed approach were characterized in terms of their total material removal depth, sidewall verticality, and top-surface roughness. The results indicated that processing with a high repetition frequency resulted in favorable sidewall verticality; however, the pillar top surfaces were susceptible to high roughness resulting from spatter and melt backfilling. To address this problem, a strategy involving the fabrication of fewer shifting layers and the use of more scan repetitions per layer was employed. This strategy mitigated cumulative defocus errors, increased the total material removal depth, and achieved a suitable balance among removal depth, sidewall verticality, and top-surface roughness. Overall, this study provides practical guidelines for the direct-write 3D microstructuring of hard materials such as SiC. These guidelines have potential applications in the rapid fabrication of chip-level heat dissipation microstructures. They can reduce process complexity and manufacturing cost while improving design flexibility for 3D thermal architectures.
Static laser scanning is an advanced approach to timber volume estimation whose accuracy now matches or exceeds that of traditional forestry methods for volume estimation, enabling its practical application in woodworking management. This study evaluates how stem volume estimation accuracy from point clouds is affected by stem surface condition (with and without bark), cross-sectional area calculation methods, point cloud filtering, and stem center determination. Results show that the stem surface condition fundamentally controls the direction and magnitude of systematic errors. For stems with bark, the cross-sectional area derived from the squared diameter caused systematic volume underestimation, which increased after filtering, whereas the quadratic mean diameter led to overestimation that was substantially reduced by filtering and approached reference values obtained from computed tomography. For debarked stems, the squared diameter method produced systematic overestimation that was effectively mitigated by filtering, while the quadratic mean diameter resulted in persistent overestimation. The volumetric method itself had only a secondary influence on accuracy. Volume estimation accuracy was primarily governed by cross-sectional area formulation and stem surface condition. For logs with bark, the squared arithmetic mean radius produced systematic volume underestimation that increased by approximately 1% after filtering, whereas the quadratic mean radius overestimated volume by about 2% after filtering. For debarked logs, volume overestimation decreased from 4.05-4.72% to 1.57-1.80% after filtering when using the squared arithmetic mean radius, while overestimation remained high (6.55-6.92%) when the quadratic mean radius was applied. In contrast, the choice of volumetric method and center determination affected volume estimates by less than 1%. These findings confirm the high potential of static laser scanning and emphasize the need for point cloud-adapted computational models.
Objectives: The VISUMAX 800 (Carl Zeiss Meditec) is the second-generation femtosecond laser for small incision lenticule extraction (SMILE), featuring faster pulse rates, automated cyclotorsion compensation (OcuLign), and automated centration (CentraLign) versus the VISUMAX 500. This systematic review and meta-analysis compared their clinical outcomes in myopia correction. Methods: Following PRISMA 2020 guidelines, we searched PubMed, EMBASE, and Web of Science through March 2026 for studies comparing the two platforms in myopia or myopic astigmatism with extractable data. Primary outcomes were predictability (SE ± 0.50 D) and astigmatism (CYL ≤ 0.50 D). Secondary outcomes included UDVA ≥ 20/20, safety (CDVA loss ≥ 1 line), R2 values, surgically induced astigmatism, axis alignment (±5°), and higher-order aberrations. Risk of bias was assessed using the ROBINS-I tool for all included studies, as no randomized controlled trials were available. Publication bias was evaluated via funnel plots, Egger's test, and Begg's test, with appropriate caution noted regarding the limited number of studies. Sensitivity analysis used the leave-one-out method. Results: Nine studies (1672 eyes: 646 VISUMAX 800, 1026 VISUMAX 500) were included. For SE ± 0.50 D, the pooled risk ratio (RR) was 1.065 (95% CI: 0.997-1.137, p = 0.061) with substantial heterogeneity (I2 = 64.7%, p = 0.004). For CYL ± 0.50 D (eight studies, 1585 eyes), the pooled RR was 1.022 (95% CI: 0.978-1.068, p = 0.333, I2 = 51.7%). Astigmatism axis within ±5° significantly favored VISUMAX 800 (RR = 1.157, 95% CI: 1.071-1.250, p = 0.0002, I2 = 0%). No statistically significant differences were observed for UDVA ≥ 20/20, safety, SEQ R2, cylinder R2, TIA, SIA, total HOAs, spherical aberration, or coma RMS. Publication bias tests showed no significant asymmetry for the primary outcomes, though these tests have limited power with fewer than 10 studies. ROBINS-I assessments classified most studies as having "serious" risk of bias due to their non-randomized designs. Conclusions: Both platforms yield comparable predictability, safety, and visual outcomes. VISUMAX 800 offers superior astigmatism axis alignment, likely due to automated compensation and centration. The borderline SE predictability warrants further randomized investigation.
Benign prostatic hyperplasia (BPH) is a common condition in aging men that significantly impacts quality of life. This study aimed to compare the perioperative outcomes and short-term efficacy of holmium laser enucleation of the prostate (HoLEP) vs. transurethral resection of the prostate (TURP) in patients with symptomatic BPH. We retrospectively analyzed data from 176 patients who underwent surgical treatment for BPH at our institution between January 2019 and December 2024. Patients were divided into two groups: HoLEP (n = 92) and TURP (n = 84). Baseline characteristics, operative parameters, postoperative complications, and functional outcomes in 6-month after surgery were compared between the groups. Baseline demographics and prostate volume were similar between the two groups. The HoLEP group showed significantly shorter operation time (58.26 ± 20.11 min vs. 84.17 ± 36.80 min, P < 0.001), shorter catheterization time (5.37 ± 1.45 vs. 6.27 ± 1.47 days, P < 0.001), and reduced hospital stay (7.33 ± 3.12 vs. 13.61 ± 4.14 days, P < 0.001). Both groups demonstrated significant improvement in functional outcomes, but HoLEP had better international prostate symptom score, higher Qmax, (all P < 0.05). HoLEP had lower urinary tract irritation (22.62% vs. 42.86%) and erectile dysfunction (16.67% vs. 29.76%, both P < 0.05). HoLEP is a safe and effective alternative to TURP for BPH, offering advantages in perioperative safety and early recovery. It may be particularly beneficial in patients with large prostates or higher bleeding risk.
Microplastic monitoring needs methods that operate directly in water with minimal sample handling. Conventional techniques such as infrared and Raman spectroscopy and pyrolysis-GC/MS provide polymer-specific information but require sample preparation and delayed laboratory analysis. We propose an optical sensor concept for real-time, in situ microplastic assessment, based on multispectral pulsed transmission in the visible range using synchronized laser-diode lines and the directly transmitted signal through an active sensor volume. After calibration on particle-free water, each particle event reduces to a water-normalized transmission whose deficit is set by geometrical beam-particle overlap and the wavelength-dependent extinction efficiency. The weak polymer absorption is represented by the Urbach-tail formalism, the refractive-index-related redirection of light by a Fresnel-based, surface- and orientation-averaged probability of direct transmission, and particle size and shape are decoupled through an effective optical length. The coupled nonlinear system is solved for the bounds of the polymer absorption coefficient per candidate geometry. Because each polymer occupies a bounded region in multi-wavelength absorption space fixed by its band gap and structural state, the method can, in principle, separate structural modifications of identical composition, such as low- and high-density polyethylene. This is a sensor concept with a model-based proof of concept, not full environmental validation. Experimental verification on real reference particles is reported separately; the present article establishes the measurement model and inversion scheme that this verification builds on.
Wire Laser Additive Manufacturing (WLAM) has emerged as a promising alternative for the fabrication and repair of components subjected to severe wear conditions due to its high deposition rate, efficient material utilization, and localized thermal control. In this study, the WLAM process using DUR600 wire as the feedstock material for the deposition of abrasion-resistant coatings was investigated. The deposited specimens were characterized by optical emission spectroscopy (OES), X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDS), Vickers microhardness testing, and dry sand/rubber wheel abrasion testing in accordance with ASTM G65. The deposits exhibited a predominantly martensitic microstructure with retained austenite, as confirmed by XRD. Hardness values ranged from 749 to 817 HV, with an average of 783 ± 18 HV, while the average volumetric loss in the abrasive wear test was 150.26 mm3. This behavior was attributed to the presence of the martensitic matrix and retained austenite, whose combined effect directly influences the tribological performance of WLAM coatings produced using DUR600 wire.
Background/Objectives: Activated irrigation techniques improve intracanal disinfection, but their impact on the clinical and radiographic healing of apical periodontitis remains unclear. This systematic review and meta-analysis evaluated the efficacy of passive ultrasonic irrigation (PUI) and laser-assisted irrigation (LAI), without adjunctive systemic antibiotics, on periapical healing compared with conventional irrigation in adult patients. Methods: Following PRISMA guidelines and prospective registration in PROSPERO (CRD420261413401), PubMed, Scopus, Embase, and Web of Science were searched up to February 2026. Randomized controlled trials (RCTs) involving adults with apical periodontitis comparing PUI or LAI against conventional syringe irrigation-with a minimum of 6 months follow-up-were included. Risk of bias was assessed using RoB 2, evidence certainty via GRADE, and a random-effects meta-analysis calculated pooled odds ratios (ORs) and 95% confidence intervals (CIs). Results: Of 1115 records identified, five randomized controlled trials involving 451 teeth fulfilled the eligibility criteria and were included in the qualitative synthesis and quantitative meta-analysis. Activated irrigation significantly increased periapical healing probability compared with conventional irrigation (OR = 2.25; 95% CI: 1.29-3.93; p = 0.004), with no statistical heterogeneity (I2 = 0%). Subgroup analyses showed significant benefits for both PUI (OR = 1.95; 95% CI: 1.08-3.54) and LAI (OR = 6.77; 95% CI: 1.63-28.12). The overall certainty of evidence was moderate due to risk of bias concerns. Conclusions: Activated irrigation techniques (PUI and LAI) were significantly associated with improved clinical and radiographic healing of apical periodontitis compared with conventional irrigation alone. Enhanced intracanal disinfection contributes to a more predictable resolution of periapical lesions without adjunctive systemic antibiotics. Further high-quality RCTs with standardized protocols and long-term CBCT-based follow-up are required to confirm these findings.