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Detection of heavy metal containment of soil pollution due to waste of paper industry using Nd:YAG laser induced breakdown spectroscopy
摘要： Detection of heavy metal containment of soil pollution has been made by using laser-induced breakdown spectroscopy (LIBS). A pulsed Nd:YAG laser (1064 nm, 8 ns, 200 mJ) was focused on to a soil sample, which is prepared in the form of pellet, at atmospheric pressure. Emission spectra taken from the waste-contaminated soil and uncontaminated soil were obtained. Plasma emissions are then detected using a multichannel analyzer (OMA) to obtain the emission line spectrum that represents the content of atoms and molecules in the target material. The spectrum is recorded and compared with the spectrum of reference standards of atoms, ions and molecules (National Institute of Standards and Technology/NIST) so that the atomic and molecular content in the sample can be known. From the results of the study it was found that there are elements of heavy metals in the form of Fe, Cd, and Mg in polluted soils.
关键词： LIBS,laser-induced breakdown spectroscopy,soil pollution,heavy metal,Nd:YAG laser
更新于2025-09-16 10:30:52
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Full-Field Erbium:YAG Laser Resurfacing: Complications and Suggested Safety Parameters
摘要： Background: Laser skin resurfacing with erbium-doped yttrium aluminum garnet (Er:YAG) lasers is a newer alternative to CO2 laser treatment, and was developed to reduce common complications. Although Er:YAG lasers have been available for years, safety parameters for efficacious resurfacing with these devices have not previously been available. Objectives: The aim of this study was to utilize one practice’s laser treatment settings and outcomes data to identify complication rates for various energies and areas of the face and to offer safe energy/depth parameters for treating each area. Methods: A retrospective chart review was performed for full-field confluent laser resurfacing patients treated with a Sciton Contour Tunable Resurfacing Er:YAG laser by the senior author. The data were retroactively analyzed with a time range of 8?years (January 2007-December 2015). Results: The overall complication rate for MicroLaserPeels (ablation of 50?μm or less) was 10.1% (20 of 198 treatments) and the rate for deep resurfacing treatments was 26.5% (71 of 268 cases). In MicroLaserPeel treatments the cheek area had the highest complication rate, followed by the forehead, nose, perioral, and eyelid areas, in that order (complication rate range, 0%-9.1%). In deep resurfacing treatments the perioral area had the highest complication rate, 38.6% of 145 cases. This was followed by the lids, cheek, nose, and forehead, in that order (complication rate range, 15.2%-20.9%). There is a correlation between increased depth of ablation and increased rate of complication. Conclusions: The study confirmed the efficacy of Er:YAG resurfacing and provides guidance for a safer approach to excellent outcomes.
关键词： complications,laser skin resurfacing,safety parameters,Er:YAG laser
更新于2025-09-16 10:30:52
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Split-face comparison of the picosecond 1064-nm Nd:YAG laser using a microlens array and the quasi-long-pulsed 1064-nm Nd:YAG laser for treatment of photoaging facial wrinkles and pores in Asians
摘要： Skin photoaging manifests deeper wrinkles and larger pore size. Various lasers have been tried for rejuvenation of photoaging skin, and the quasi-long-pulsed 1064-nm neodymium:yttrium-aluminum-garnet (Nd:YAG) laser is one promising treatment option. New types of laser device are emerging, including devices operating with picosecond pulse duration combined with a microlens array, which are regarded as a new breakthrough for skin rejuvenation. We aimed to evaluate the clinical effectiveness and safety of the picosecond 1064-nm Nd:YAG laser using a microlens array compared with the quasi-long-pulsed 1064-nm Nd:YAG laser in a split-face design. We designed a split-faced, prospective study and enrolled 25 subjects with photoaging facial wrinkles and enlarged pores. Each facial area was randomly assigned to undergo treatment with either the picosecond 1064-nm Nd:YAG laser (Pico-arm) or the quasi-long-pulsed 1064-nm Nd:YAG laser (Quasi-arm). We performed five laser sessions at 2-week intervals, and final results were assessed after 20 weeks after the initial laser session. We used a five-point global assessment scale, wrinkle and pore index derived from 3D camera analysis. We enrolled a total of 25 subjects (24 females and 1 male) with Fitzpatrick skin types III to IV and a mean age of 63.8 ± 5.7 years. After treatment, 54.2% of subjects in the Pico-arm reported at least moderate improvement in visible pores compared with 41.7% of the Quasi-arm (P = 0.001). A total of 12.5% of subjects in the Pico-arm showed moderate improvement in wrinkles versus 4.2% of the Quasi-arm (P = 0.125). There was a 41.3% reduction in the pore index in the Pico-arm compared to a 3.9% increase in the Quasi-arm (P = 0.048). There was a 16.4% reduction in the wrinkle index in the Pico-arm compared with a 0.5% reduction in the Quasi-arm (P = 0.01). Pain assessment score was higher in the Pico-arm than the Quasi-arm (3.65 ± 1.70 vs 1.28 ± 1.28, P = 0.001). No serious adverse events occurred during the study. Our findings suggest that the picosecond 1064-nm Nd:YAG laser with a microlens array is as effective as the quasi-long-pulsed 1064-nm Nd:YAG laser for treatment of photoaging wrinkles and pores.
关键词： Nd:YAG laser,Photoaging,Microlens array,Wrinkle,Picosecond,Pore
更新于2025-09-16 10:30:52
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Laser-Aided Enamel Conditioning: A Comparison of Microleakage Under Brackets Following Different Aging Procedures
摘要： Objective: To evaluate microleakage under the orthodontic adhesives applied following two version of erbium:yttrium aluminum garnet (Er:YAG) laser-aided enamel conditioning after thermal and thermomechanical simulators. Materials and Methods: A comparative analytical study based on metal braces bonded on the enamel of extracted teeth (n = 160) etched with acid, Er:YAG laser and Er:YAG laser with an X-Runner handpiece, and self-etch adhesives. An arch wire was ligatured to samples which were embedded in acrylic blocks by two with periodontal ligaments. The specimens were subdivided into two groups: those aged with thermal cycling and thermomechanical aging procedures. The samples were immersed in basic fuchsin solution (0.5%) for 24 h. Buccolingual sections were performed on the mesial and distal wings of the braces. The color penetration at the gingival and occlusal margins of the adhesive-bracket and enamel-adhesive was evaluated under a stereomicroscope. The median and mean values of microleakage in both groups were evaluated with Kruskal–Wallis and Mann–Whitney U tests (P < .05). Results: The highest microleakage was recorded in the gingival part of the samples aged with the thermomechanical aging procedure (P = .001). The amount of microleakage generally increased in the samples subjected to thermomechanical loading, but the only significant difference was recorded in the gingival part in each four different conditioning methods. Conclusion: Microleakage of the phosphoric acid-etched groups was recorded with lower values for both aging methods. Thermomechanical aging should be included to microleakage studies due to increased microleakage on gingival side for all etching groups.
关键词： thermomechanical aging,Chewing simulation in orthodontics,microleakage,X-Runner handpiece,Er:YAG Laser
更新于2025-09-16 10:30:52
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An Integrated Approach for optimization of Pulsed ND: YAG Laser Beam Welding process
摘要： Laser beam welding is a non-traditional, advanced technique used for similar & dissimilar materials and is widely used in various industries like automobile, aerospace, nuclear reactors, etc. at a faster pace. As it is a complex process, it is very difficult to find the optimal process parameters. The primary point of welding is to acquire a high quality joints and requiring little to no effort. However, without optimization, it is impractical to accomplish minimal effort welding. The principle work of this exploration is to display, break down and improve weld bead geometry in the powerful ND: YAG laser butt welding of Inconel 625. However, in view of the literature review, the responses are continuous and have impact on the welding geometry. In this way the feasible varieties of the judgment factors are started by coordinating trial tests. The Design of Experiment (DOE) system is used to generating the experimental plan and then conducting the experiments according to the plan. After recording the responses Reaction Surface Methodology (RSM) is received for precise expectation numerical models to evaluate the response variables and are created from the experimental information. Artificial Neural Networks (ANNs) have adopted from the MATLAB software for analysing the output response regression and provide the best curve fitting among the input and output variables.
关键词： DOE,ANN,Inconel 625,ND:YAG Laser,RSM
更新于2025-09-16 10:30:52
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Optimization of Process Parameters and Comparative Study on Bi-Metallic Joints Developed by High Temperature Nicrobrazing, Laser and GTAW Joining Processes
摘要： High Temperature Nicrobrazing of AISI 316 and 316 L stainless steels has been studied by comparing with pulsed laser and gas tungsten arc welding processes. Fabrication of instrumented irradiation capsule for evaluating the irradiation performance of fuel and structural materials in a nuclear reactor requires development of thin wall joints capable of withstanding high temperature and/or internal pressure. Thin wall joints for high temperature (~550 °C) applications can be made by Laser Beam Welding (LBW), Gas Tungsten Arc Welding (GTAW) and High Temperature Brazing (HTB) methods. Using these methods, joints have been prepared and tests such as helium leak test (HLT) and microhardness test have been carried out. Microstructures were also evaluated. A comparative study has been performed on these joining methods to identify the suitable methods for high temperature applications. No observable leak was found during HLT. Microstructures of joints shows variation in solidification morphology due to difference in heat sources. It has been observed that the joint prepared by high temperature brazing process is having higher microhardness value than the joints prepared by LBW and GTAW processes. Further, it has been observed that LBW joints have better mechanical properties than GTAW joints and HBW joints.
关键词： AISI 316,GTAW,HTB,Tube to End plug,Nd:YAG Laser welding,AISI 316L
更新于2025-09-16 10:30:52
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Immediate effect of pulsed high-intensity neodymium-doped yttrium aluminum garnet (Nd: YAG) laser on staphylococcus aureus and pseudomonas aeruginosa growth: an experimental study
摘要： The aim of this study was to evaluate the effect of pulsed high intensity neodymium-doped yttrium aluminum garnet (Nd: YAG) laser on staphylococcus aureus (S. aureus) and pseudomonas aeruginosa (P. aeruginosa) bacterial growth, which cause many health problems and establish which doses are effective in bacterial inhibition. Five samples of S. aureus and five samples of P. aeruginosa were prepared in the microbiology lab, one used as control sample and the other 4 samples acted as experimental samples. The experimental samples received pulsed high intensity Nd: YAG laser with a total dose of 500, 600, 700 and 800 joules. The primary measures are colony count and the percentage decrease in colony count, the colony count was assessed at baseline and after 24 h of laser application. There was significant decrease in colony count and the percentage decrease in colony count after pulsed high intensity Nd: YAG laser application in all experimental samples of S. aureus and P. aeruginosa after 24 h of application for all doses (500, 600, 700 and 800 j) as compared with the control sample, with the most effect in higher doses of pulsed high intensity Nd: YAG laser than lower doses in both types of bacteria. pulsed high intensity Nd: YAG laser was found to be an effective modality for inhibition of S. aureus and P. aeruginosa growth after a single application.
关键词： Bacterial growth,Pulsed high intensity neodymium-doped yttrium aluminum garnet (Nd: YAG) laser,Colony count
更新于2025-09-16 10:30:52
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Objective assessment of YAG laser vitreolysis in patients with symptomatic vitreous floaters
摘要： Background: To objectively evaluate YAG laser vitreolysis for symptomatic vitreous floaters using color photo imaging. Methods: In this interventional and prospective study, 32 eyes of 32 patients with symptomatic vitreous floaters secondary to posterior vitreous detachment (PVD) were treated with a single session of yttrium aluminum garnet (YAG) laser. Primary outcomes were objective and subjective changes measured by masked grading of color fundus photographs and National Eye Institute Visual Functioning Questionnaire 25 (NEI VFQ-25), respectively. Secondary outcomes included Early Treatment Diabetic Retinopathy Study (ETDRS), best-corrected visual acuity (BCVA) and adverse events. Wilcoxon signed-rank test was used to analyze the results of the objective and subjective assessments at each time point. P < 0.05 was considered statistically significant. Results: Thirty-two patients (32 eyes; 13 men and 19 women) with symptomatic vitreous floaters were enrolled in this study (mean age: 59.4 years). All study patients were followed up for 6 months. Following the laser vitreolysis, there was a statistically significant improvement in both the near visual function (z = ? 2.97; p = 0.003; r = 0.633) and visual disturbance rate (z = ? 3.97; p < 0.001; r = 0.84). Distance visual function did not show statistically significant difference after the laser procedure (p = 1.00). Color fundus photograph did reveal vitreous opacity improvement over time in 93.7% of study eyes (partial improvement in 37.5% and total improvement in 56.2% of study eyes). During the follow-up period, recurrence of vitreous floaters, BCVA deterioration and adverse events were not observed. Conclusions: YAG laser vitreolysis decreased the amount of vitreous floaters opacities seen on color fundus imaging and improved related symptoms according to the NEI VFQ-25 responses.
关键词： Vitreous floaters,NEI VFQ-25 questionnaire,YAG laser,Vitreolysis,Color fundus photograph
更新于2025-09-16 10:30:52
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Evolution of surface morphology of Er:YAG laser-machined human bone
摘要： The extensive research on the laser machining of the bone has been, so far, restricted to drilling and cutting that is one- and two-dimensional machining, respectively. In addition, the surface morphology of the laser machined region has rarely been explored in detail. In view of this, the current work employed three-dimensional laser machining of human bone and reports the distinct surface morphology produced within a laser machined region of human bone. Three-dimensional laser machining was carried out using multiple partially overlapped pulses and laser tracks with a separation of 0.3 mm between the centers of consecutive laser tracks to remove a bulk volume of the bone. In this study, a diode-pumped pulse Er:YAG laser (λ = 2940 nm) was employed with continuously sprayed chilled water at the irradiation site. The resulting surface morphology evolved within the laser-machined region of the bone was evaluated using scanning electron microscopy, energy dispersive spectroscopy, and X-ray micro-computed tomography. The distinct surface morphology involved cellular/channeled scaffold structure characterized by interconnected pores surrounded by solid ridges, produced within a laser machined region of human structural bone. Underlying physical phenomena responsible for evolution of such morphology have been proposed and explained with the help of a thermokinetic model.
关键词： Laser osteotomy,Laser machining,Surface morphology,Er:YAG laser,Scaffold
更新于2025-09-12 10:27:22
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Laser treatment of epidermal nevi: A multicenter retrospective study with long-term follow-up
摘要： Background: Patients with epidermal nevi strongly demand cosmetic improvement. Laser treatment appears appealing and is frequently used in clinical practice. Nevertheless, large series with long-term follow-up are missing, preventing definitive conclusions about its real benefit. Objective: To evaluate the long-term effectiveness and safety of lasers for epidermal nevi. Methods: Bicentric, retrospective, cohort study, including all patients treated with a laser for an epidermal nevus with more than a one-year follow-up. Results: Seventy patients were treated for different types of epidermal nevi, mostly with ablative lasers: 23 verrucous epidermal nevi, 16 nevi sebaceous, 26 Becker nevi, two inflammatory linear verrucous epidermal nevi, one smooth-muscle hamartoma, one rounded and velvety epidermal nevus, and one nevus lipomatosus superficialis. The follow-up period ranged between 12 and 127 months (median 37 months). Better results, fewer recurrences, and higher patient satisfaction were noted in treatments for verrucous epidermal nevi than for nevi sebaceous. Q-switched (QS) lasers failed to show any degree of improvement in almost all patients with Becker nevus. Limitations: The retrospective nature of the study. Conclusions: Ablative lasers can treat verrucous epidermal nevi with good long-term esthetic results, but they have limited long-term efficacy for nevus sebaceous. Q-switched lasers failed to improve Becker nevi.
关键词： Epidermal nevus,Becker nevus,ILVEN,nevus lipomatosus superficialis,ablative laser,Er:YAG laser,CO2 laser,verrucous epidermal nevus,Becker’s nevus,nevus sebaceous,smooth-muscle hamartoma
更新于2025-09-12 10:27:22