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- 2019
- Titanium Dioxide Nanaoparticles
- Hep-2 cell line
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- Q-switched pulsed Nd:YAG laser
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- University of Technology (UOT)
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Dose-dependent effect of the pulsed Nd:YAG laser in the treatment of crushed sciatic nerve in Wister rats: an experimental model
摘要： The objective of the study was to investigate the efficacy of three energy densities 4, 10, and 50 J/cm2 of pulsed Nd:YAG laser for the treatment of crushed sciatic nerve in Wister rats by evaluating changes in the sciatic functional index and the electrophysiology.A total of 180 Wistar rats were involved in the study. Rats were randomly assigned to five groups. Rats were subjected to the sciatic nerve crushing. Control negative (CONT-ve), which received no crushing; control positive (CONT+ve), which received crushing with no laser; and HILT-4, HILT-10, and HILT-50 groups, which received pulsed Nd:YAG laser (10 Hz, 360 mJ/cm2) with energy densities 4, 10, and 50 J/cm2, respectively. The SFI, the amilitude of compound motor action potential (CMAP) and sciatic motor nerve conduction velocity (MNCV) were measured before and after seven, 14, and 21 days after crushing. For the SFI and electrophysiological analysis, repeated measures ANOVA is used, followed by Bonferroni’s repeated-measures test. Statistical significance was set at p < 0.05. After one week, there was no significant difference in SFI, CMAP, and MNCV among the three laser groups with significant changes between them and CONT-ve and CONT+ve groups. There was a significant increase in either CMAP amplitude or MNCV after 14 days with significant decrease in the SFI after 21 days among all treatment groups. The pulsed Nd:YAG laser applied with energy densities 4, 10, and 50 J/cm2 significantly decreased the SFI and increased the CMAP and MNCV of the crushed sciatic nerve in Wister rats. Among laser doses, the difference in the rate of recovery in the electrophysiology was found after two weeks while in the SFI after three weeks. The improvement after the nerve injury was time and dose dependent.
关键词： Pulsed Nd:YAG laser,Crushing injury,Electrophysiology,Energy density,Sciatic functional index
更新于2025-09-23 15:19:57
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Nd:YAG Laser Posterior Capsulotomy in Adult Patients with Uveitis
摘要： Purpose: To study the complication rate of Nd:YAG laser posterior capsulotomy in patients with uveitis. Method: Retrospective case note analysis of pseudophakic uveitis patients having undergone Nd:YAG laser posterior capsulotomy between January 2016 and December 2018. Complications documented included uveitis flare, raised intraocular pressure, intraocular lens damage/displacement, cystoid macular edema, and retinal detachment. Results: There were 39 eyes of 38 patients (20M, 18F; age 27–89 years). Mean interval between cataract surgery and laser was 55 months (range 8–286 months). Mean laser energy was 79 mJ (range 33–207 mJ). At 3 months 62% of eyes achieved a 2–5 Snellen line improvement that was maintained at 12 months. Vision was unchanged in 21% of eyes due to preexisting pathology, with no eyes having worse vision. No post-laser complications were documented. Conclusions: Nd:YAG laser posterior capsulotomy is a safe procedure in uveitis patients, resulting in a good improvement in vision.
关键词： pseudophakia,Nd:YAG laser,posterior capsulotomy,complications,Uveitis
更新于2025-09-23 15:19:57
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Experimental Study of the Technology Parameters Affect in the Laser Welded Joints
摘要： The laser welding technology is improving immediately rapidly nowadays. It has many advantages again the traditional welding technologies. The heat affected zone in case of the laser welding is very thin and the penetration of the joint is depth. This high energy technology work by a focused high energy laser light accompanied by protective gases. For welding process well known the different laser devices (gas laser, solid-state laser, disc laser). The effect of the gases and the technological parameters are not well known yet. In this work, we wanted to find some relationship between the welding parameters and the joint mechanical properties. To find this relationship it was welded the joint by different technologies parameters and the samples experimented the joint mechanical properties with different parameters and controlled by the experimental way.
关键词： technology parameters,Nd:YAG laser,laser welding,joint mechanical properties,CO2 laser
更新于2025-09-23 15:19:57
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Temperature changes during laser lithotripsy with Ho:YAG laser and novel Tm-fiber laser: a comparative in-vitro study
摘要： Aim The aim of this study was to compare the thermal effects of Ho:YAG and Tm-fiber lasers during lithotripsy in an in-vitro model via real-time temperature measurement. Methods We compared a Ho:YAG laser (pav up to 100 W, Lumenis, Yokneam, Israel) and a superpulse Tm-fiber laser (SP TFL, pav up to 40 W, NTO IRE-Polus, Fryazino, Russia), both equipped with 200 μm bare-ended fibers. The following settings were used: 0.2 J, 40 Hz (nominal pav 8 W). Power meter FieldMaxII-TO (Coherent, Santa Clara, CA, USA) was used to verify output laser power (pav). Each laser was fired for 60 s in two setups: (1) thermos-insulated (quasi-adiabatic) cuvette; (2) actively irrigated setup with precise flow control (irrigation rates 0, 10, 35 mL/min). Results Power measurements performed before the test revealed a 10% power drop in Ho:YAG (up to 7.2 ± 0.1 W) and 6.25% power drop in SP TFL (up to 7.5 ± 0.1). At the second step of our experiment, irrigation reduced the respective temperatures in the same manner for both lasers (e.g., at 35 mL/s SP TFL ? 1.9 °C; for Ho:YAG laser ? 2.8 °C at 60 s). Conclusion SP TFL and Ho:YAG lasers are not different in terms of volume-averaged temperature increase when the same settings are used in both lasers. Local temperature rises may fluctuate to some degree and differ for the two lasers due to varying jet streaming caused by non-uniform heating of the aqueous medium by laser light.
关键词： Ho:YAG laser,Laser lithotripsy,Thermal effect,Thulium fiber laser,In-vitro
更新于2025-09-23 15:19:57
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Effects of Er:YAG Laser on the Attachment of Human Periodontal Ligament Fibroblasts to Denuded Root Surfaces Simulating Delayed Replantation Cases: An <i>In Vitro</i> Study
摘要： Objective: To investigate the effects of Er:YAG laser on the attachment of human periodontal ligament ?broblasts (hPDLFs) to denuded root surfaces simulating delayed replantation cases. Background data: Dental avulsion is one of the most severe dental traumas, which is often treated with replantation. In delayed replantation scenarios, poor prognosis, including root resorption, usually occurs due to poor root surface conditioning and nonviable hPDLF attachment. Methods: Thirty-six root fragments (5 · 5 · 2 mm) were obtained from periodontium tissue-free premolar root surfaces. Specimens were randomly and equally assigned to the following: Group A, untreated control; Group B, 25 J/cm2 and 10 Hz of Er:YAG laser irradiation; and Group C, 50 J/cm2 and 10 Hz of Er:YAG laser irradiation. Some specimens in each group were then prepared for surface topography visualization under SEM, others were subjected to coculture with hPDLF suspension, and cell adhesion was further evaluated by SEM. Results: Group A presented homogenous smooth root surface, with fewer and round-shaped cells attached; Group B and C exhibited rather rough and irregular morphologies, and spindle-shaped ?broblasts were ?rmly attached by numerous lamellipodia and extensions. After a 3-day coculture, the number of ?broblasts attached in Group A was signi?cantly lower compared with the other two laser-treated groups ( p = 0.008 < 0.05). No signi?cant alterations were observed between the two laser groups ( p = 0.135 > 0.05). Conclusions: Er:YAG laser-treated root surfaces are compatible for the attachment of PDLFs, which suggests that Er:YAG laser irradiation may be used as a promising strategy for root surface conditioning in delayed replantation cases.
关键词： delayed replantation,root surface conditioning,Er:YAG laser,human periodontal ligament ?broblasts
更新于2025-09-23 15:19:57
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Investigation on solidification cracks in pulsed laser spot welding of an AZ31 magnesium alloy
摘要： A direction-dependent model of solidification crack initiation and propagation is established to analyze the influence of the melt pool shape on the distribution of solidification cracks in pulsed laser spot welding. The formation direction of the initial crack is related to the variation of the solidification parameters. When the aspect ratio of the spot welds with a default Rectangular pulse is greater than 0.3 and less than 0.8, an initial crack is formed in the 45° direction of the mushy zone, and then the crack propagates along the grain boundary. That is, the solidification cracks are distributed in the direction of 45° on both sides of the surface center of the welding cross-section. When the aspect ratio of the spot welds is less than 0.3 or greater than 0.8, an initial crack is formed in the 90° direction of the mushy zone, and then the solidification crack is vertically distributed at the center of the welding cross-section. The Step-Down-10ms-0.3P pulse can significantly reduce the solidification rate of the melt pool interface, preventing the formation of initial cracks in the sensitive directions of the spot welds with an aspect ratio less than 0.8, thereby eliminating solidification cracks.
关键词： Molten pool shape,Solidification cracking prevention,Cracking distribution,Nd:YAG laser spot welds,Cracking initiation direction
更新于2025-09-23 15:19:57
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Tattoo??removal a??the artistic state of the art.a?? Tattoo on forehead, nose, and chin: Successful removal with modified R20 technique using low-fluence Q-switched Nd YAG laser: A case report
摘要： Background: Tattooing is an ancient practice that has been performed all over the world which is used to beautify the skin and augment beauty. Regrettable tattoos are treated with Q switch lasers, in many sessions, and the effectiveness is doubtful. Objectives: The aim of this paper is to demonstrate how a unique protocol of R20 Q switch Nd YAG laser, can be employed successfully in removing long standing facial tattoos, in skin type IV, in an effective disciplined timing and cost wise modalities. The adopted method was a-4 single passes, with 20 minutes gap respectively. Methods and Results: A lady received the conventional Q switch laser at one session, with no noticeable results. On the other session, she received the R20 method, and an immediate whitening reaction was observed. No adverse reactions were noted. Conclusion: The R20 Q technique is very effective tool in a single treatment session than the conventional multiple laser sessions, in tattoo removal, and I would invite other dermatologists utilize it in their clinical setting. This method does not need any newer laser technology, clears the tattoo fast, and cuts down unnecessary treatment duration and cost.
关键词： Q switched Nd YAG laser,R20,laser tattoo removal
更新于2025-09-23 15:19:57
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Investigation on the effect of power and velocity of laser beam welding on the butt weld joint on TRIP steel
摘要： In this study, the characterization of laser weld joint on transformation-induced plasticity (TRIP) steel sheets coupled with Nd:YAG laser welding was investigated, and the influence of welding conditions like angle of weld, power of laser, and welding speed on the strength of the joint was measured. The microstructure, tensile behavior, and microhardness of TRIP laser-welded sheets were examined in detail. The power was maintained constant, i.e., 1800 W, and by relatively varying the velocity from 25 to 30 mm/s, the strength of the joint increased drastically to 11%. In contrast, by varying the power, the effect of velocity was reduced; however, the point performance was enormously stable. Finally, the microhardness behavior of the heat-affected zone and fusion zone was investigated and discussed.
关键词： butt weld joint,heat treatment,TRIP steel,Nd:YAG laser,laser welding
更新于2025-09-23 15:19:57
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Safety and Efficacy of YAG Laser Vitreolysis for the Treatment of Vitreous Floaters: An Overview
摘要： Emerging evidence has suggested that the entoptic phenomena associated with vitreous opacities (i.e. vitreous floaters) are more bothersome than previously believed. In addition, the prevalence of vitreous floaters is likely increasing due to the evolving global pandemic of myopia. The use of YAG laser vitreolysis for the treatment of annoying vitreous floaters has attracted significant attention in recent years as the technique offers a number of potential advantages. Unfortunately, the currently available evidence that is needed to guide clinical practice is both very limited and contradictory. As a consequence, the technique remains highly controversial. A review of the existing literature sheds light on patient- and treatment-related factors that may significantly affect both the effectiveness and the safety of the procedure. The current article discusses important aspects of key publications on the topic, offers suggestions for clinical practice, and highlights unmet needs that should be addressed by future research.
关键词： Vitreous floaters,Weiss ring,PVD,Floaters,Posterior vitreous detachment,Vitreolysis,YAG,Ophthalmology,Myodesopsia
更新于2025-09-23 15:19:57
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Study on the Main Influencing Factors in the Removal Process of Non-Stick Fluoropolymer Coatings Using Nd:YAG Laser
摘要： The coatings with fluoropolymer resins rich in fluorinated ethylene propylene (FEP) and polytetrafluoroethylene (PTFE) are applied as anti-adherent coatings on aluminum–magnesium substrates for use in food containers. In many cases, due to wear, they must be stripped for the application of a new coating on the same substrate. There are several processes for this: blasting, plasma, pyrolysis, chemical processes, laser, high pressure water, and combinations of these. This work focuses on the characterization of the main factors that condition the FEP coating removal process by a continuous wave (CW) Nd:YAG laser, and on the determination of the efficiency of this type of technology used for this purpose. Stripping surface per unit of time and energy consumption per unit area has been determined among other efficiency indicators. Regarding the characterization of the coating object of study, its thickness, surface roughness, contact angle, microhardness and absorbance-reflectance responses have been determined, and the results have been compared with those obtained in the case of PTFE. In addition, to evaluate the mechanical damage caused in the substrate after coating removal by (CW) Nd:YAG laser, the tensile strength, Vickers hardness, Ra and Rz roughness, and the substrate thickness have been measured and analyzed.
关键词： laser coating removal,PTFE coatings,FPE coatings,Nd:YAG laser,laser stripping
更新于2025-09-19 17:15:36