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Enhancing cutaneous delivery with laser technology: almost there, but not yet
摘要： Preclinical research has shown the potential of different laser-based strategies (direct ablation, photothermolysis and mechanical waves) to overcome the stratum corneum and facilitate the cutaneous delivery of drugs. However, specific protocols for the routine use of these strategies have not been stablished yet. The aim of this review has been to provide the readers with a view of the translational prospects of the different laser technologies with regards to their utility for enhancing the penetration of drugs.
关键词： Photothermolysis,Direct ablation,CO2 laser,Er:YAG laser,Mechanical waves,Medical lasers
更新于2025-09-19 17:13:59
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Experimental and Numerical Study of AISI 4130 Steel Surface Hardening by Pulsed Nd:YAG Laser
摘要： Laser surface transformation hardening (LSTH) of AISI 4130 was investigated by a Nd:YAG pulsed laser. Laser focal height (LFH), pulse width (LPW), scanning speed (LSS), and power (LP) varied during the experiments. The microstructure of the treated zone was characterized by optical (OM) and field emission scanning electron microscopy (FESEM). Micro-hardness was measured in the width and depth directions. Results showed that the hardness and depth of hardened layer increased by decreasing the LSS and the laser focal position (LFP), and by increasing the LPW. The results were compared with those obtained by furnace heat treatment of the same steel. Eventually, a finite element model was employed for the simulation of the LSTH of AISI 4130 steel and calculation of the heat-treated zone. The results showed that the model can predict with accuracy the temperature profile and the size and the shape of the laser hardened region.
关键词： Nd:YAG pulsed laser,laser surface transformation hardening,FEM model,AISI 4130 steel
更新于2025-09-19 17:13:59
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Adjunctive effects of laser therapy on somatosensory function and vasomotor regulation of periodontal tissues in patients with periodontitisa?? A randomized controlled clinical trial
摘要： Background: The purpose of this prospective study was to compare the changes in periodontal somatosensory function and microcirculation in patients with periodontitis following initial treatment with scaling and root planing (SRP) with or without adjuvant laser therapy. Methods: Twenty-four patients suffering from periodontitis were recruited and randomly allocated into a split-mouth design to either SRP combined laser therapy side (test side) or SRP only side (control side). All treatments were performed by the same investigator at a single visit. Laser Doppler Flowmetry (LDF) and Quantitative Sensory Testing (QST) were performed at baseline (W0), 1 week (1W), 2 weeks (2W), and 4 weeks (4W) after treatment on both sides of the attached gingiva of the maxillary lateral incisor. Clinical examination including pocket probing depth (PPD) and bleeding on probing (BOP) was performed at W0, 2W, and 4W on both sides. Data were analyzed with two-way analysis of variance (ANOVA). Results: The PPD and BOP significantly improved after treatment (P <0.001). The LDF values were significantly decreased on both sides at all follow-up time points (P <0.001), temperature was increased only on the test side (P =0.017) whereas there was no significant change on the control side (P=0.792). Significantly less sensitivity was observed for all QST parameters (P <0.030) except for warmth detection after treatment. Conclusion: Adjunctive use of laser therapy did not provide any significant clinically advantage or additional effects on the recovery of periodontal somatosensory function or gingival microcirculation in the present study.
关键词： Quantitative sensory testing,periodontal somatosensory function,inflammation,Nd:YAG laser,blood flow
更新于2025-09-19 17:13:59
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Ultrasonic-Enhanced Fabrication of Metal Nanoparticles by Laser Ablation in Liquid
摘要： Laser ablation in liquid (LAL) is known to be a promising method for synthesizing metal nanoparticles. In this study, gold and silver nanoparticles were fabricated by ultrasonic-assisted LAL. Gold and silver plates were ablated using a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser, with a wavelength of 532 nm and energy of 26.4 J cm?2, in distilled water in the presence and absence of an ultrasonic ?eld. The fabricated solution was analyzed with an ultraviolet?visible (UV?vis) nanoparticle colloidal spectrometer, a transmission electron microscope (TEM) with energy-dispersive X-ray spectroscopy (EDS), and ζ-potential measurement. The craters on the silver plates were analyzed by a scanning electron microscope (SEM), a laser microscope, and MATLAB to observe their morphology and calculate the volume to obtain the concentration of the fabricated nanoparticle solution. Optical emissions were observed to study the characteristics of the laser. The results showed that ultrasonic-assisted LAL has considerable potential for fabricating superior metal nanoparticles.
关键词： Silver nanoparticles,Ultrasonic-assisted,Nd:YAG laser,Laser ablation in liquid,Gold nanoparticles
更新于2025-09-19 17:13:59
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Quantitative spatially resolved <i>post-mortem</i> analysis of lithium distribution and transition metal depositions on cycled electrodes <i>via</i> a laser ablation-inductively coupled plasma-optical emission spectrometry method
摘要： Diminishing the loss of performance of lithium ion batteries (LIBs) is a challenge that is yet to be ful?lled. Understanding of deterioration processes and mechanisms (i.e., so-called aging) requires analytically accurate examination of aged cells. Changes in the distribution of lithium or transition metals in the LIB cells can in?uence their cycle and calendar life signi?cantly. As electrochemically treated cells and especially their electrodes do not age homogeneously and the local electrochemistry (e.g. deposition patterns) is strongly dependent on surface properties, bulk analysis is not a satisfactory investigation method. Therefore, a surface sensitive method, namely laser ablation-inductively coupled plasma-optical emission spectrometry (LA-ICP-OES) is presented. LIB cells with lithium metal oxide LiNi1/3Co1/3Mn1/3O2 (NCM111) as cathode material and graphite as anode material are investigated using a 213 nm Nd:YAG laser.
关键词： graphite,aging,laser ablation-inductively coupled plasma-optical emission spectrometry,NCM111,LA-ICP-OES,LIBs,Nd:YAG laser,lithium ion batteries
更新于2025-09-19 17:13:59
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Easy-handling minimum mass laser target scaffold based on sub-millimeter air bubble -An example of laser plasma extreme ultraviolet generation-
摘要： Low density materials can control plasma properties of laser absorption, which can enhance quantum beam generation. The recent practical extreme ultraviolet light (EUV) is the first industrial example of laser plasma source with low density targets. Here we propose an easy-handling target source based on a hollow sub-millimeter microcapsule fabricated from polyelectrolyte cationic and anionic surfactant on air bubbles. The lightweight microcapsules acted as a scaffold for surface coating by tin (IV) oxide nanoparticles (22–48%), and then dried. As a proof of concept study, the microcapsules were ablated with a Nd:YAG laser (7.1 × 1010 W/cm2, 1 ns) to generate 13.5 nm EUV relatively directed to laser incidence. The laser conversion efficiency (CE) at 13.5 nm 2% bandwidth from the tin-coated microcapsule (0.8%) was competitive compared with bulk tin (1%). We propose that microcapsule aggregates could be utilized as a potential small scale/compact EUV source, and future quantum beam sources by changing the coating to other elements.
关键词： extreme ultraviolet light,tin oxide nanoparticles,Nd:YAG laser,microcapsule,low density materials,laser plasma
更新于2025-09-19 17:13:59
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<p>Effect of Topical 5-Fluorouracil Alone versus Its Combination with Erbium:YAG (2940 nm) Laser in Treatment of Vitiligo</p>
摘要： Purpose: To compare the efficacy of topical 5-FU as monotherapy to combined therapy of topical 5-FU and Er:YAG (2940 nm) laser in the treatment of non-segmental vitiligo (NSV). Methods: This is a prospective randomized comparative study. Thirty patients diagnosed with NSV were recruited from the dermatology outpatient clinics of the Medical Research Centre of Excellence, the National Research Centre and the National Institute of Laser Enhanced Sciences. Our study group was divided into two subgroups, Group 1 was subjected to ablative Er:YAG and 5-FU cream and Group 2 applied topical 5-FU cream. Three treatment sessions were repeated every 4 to 6 weeks and patients were followed up to 9 months. Repigmentation was assessed by digital photography and subsequent computer based image analysis. Results: Repigmentation of Group 1 patients ranged from 0 to 70% (mean 12±7%) whilst in Group 2 this ranged from 0 to 5% (mean 1.4±0.8%). In Group 1 repigmentation was mild in 22/30 (73.3%) and moderate to severe in 3/30 (10%) starting after 3 months and persisted or increased during the period of follow up to 9 months. Groups 1 and 2 were subdivided into A and B, vitiligo involving non-resistant and resistant areas respectively. Group 1A showed more repigmentation (mean 13.8±8.5%) than Group 1B (mean 9.8±4.5%) and Group 2A showed more repigmentation (mean 1.5±1%) than Group 2B (mean 1.3±0.5%). Conclusion: The combination of Er:YAG with 5-FU is safe and effective in treating and improving outcome in vitiligo especially of non-resistant areas. Computer based image analysis of vitiliginous lesions and assessing post-therapy response is an easy, quick, and reliable method.
关键词： 5-fluorouracil,Er:YAG,ablative,image analysis,resistant,vitiligo
更新于2025-09-19 17:13:59
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Numerical simulation of temperature distribution and experimentation in laser beam welding of SS317L alloy
摘要： In the present study stainless steel 317L grade was chosen for joining using 400w Nd-YAG laser beam welding process. Tensile strength and temperature distribution are considered as output responses while Welding current, Frequency, Pulse width are taken as process parameters. A butt configuration of 5 mm thick plate of austenitic steel alloy and K-type digital thermocouple was used to observe the temperature experimentally. The welded plates are cut using Electro-discharge machining to prepare Tensile test specimens according to ASTME21 standard. The specimens are tested to get stress-strain graphs and ultimate tensile strengths for all the 9 cases (as per L9 Orthogonal array). Additionally, a 2D transient thermal-structural numerical simulation model was developed to simulate the complete laser welding process. The effect of each parameter has been studied experimentally and numerically. Analysis of variance (ANOVA) has been used for finding out the contribution of each input factor on the output response with the help of MINITAB software. The optimised values of process parameters are utilised to get the thermal profiles and heat-affected zone using finite element simulations. The finite element calculation of process was carried out by a parametric design language APDL available in the ANSYS finite element code. The temperature values obtained using finite element simulation and experiments are matching reasonably good with an error of 12% hence the developed simulated model can be used to study related parameters.
关键词： Tensile strength,Laser beam welding,Optimization,Simulation,FEM,Nd-YAG laser
更新于2025-09-19 17:13:59
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Percutaneous transhepatic laser lithotripsy for intrahepatic cholelithiasis: A technical report
摘要： Advances in interventional radiology have seen the adaptation of urological endoscopic laser techniques to treat biliary tract calculi. Percutaneous transhepatic biliary laser lithotripsy provides an effective alternative procedure for the management of intrahepatic or conventionally refractory choledocholithiasis which would otherwise require invasive and high-risk surgical intervention. Several small studies have validated the procedure for management in this subset of patients, with most achieving 100% calculi clearance with minimal complications. Most patients are suitable for percutaneous transhepatic biliary laser lithotripsy. Preprocedural imaging is useful for evaluating stone burden and planning percutaneous access. Holmium lasers are commonly used and act by vaporising water particles on and in the calculi, fragmenting the stone via thermal expansion. A series of catheters, wires, sheaths and dilators are used to allow introduction of the choledochoscope and laser so that calculi can be targeted. Percutaneous transhepatic biliary laser lithotripsy is often used in conjunction with balloon dredging and biliary stricture dilatation. Only experienced interventionalists should perform this procedure, and users should be aware of associated hazards. Repeat percutaneous transhepatic cholangiography is routinely performed to con?rm eradication of stones. Treatment of biliary calculi and obstruction is important in preventing diseases such as cholangitis and cirrhosis. For patients unsuitable for conventional treatment, percutaneous transhepatic laser lithotripsy is a safe and effective alternative when performed by experienced interventional radiologists. Preprocedural planning is imperative to procedure success.
关键词： cholangioscopy,laser,percutaneous biliary lithotripsy,intrahepatic cholelithiasis,holmium: YAG
更新于2025-09-19 17:13:59
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Corneal Inlay Damage After Cosmetic Laser Treatment of the Eyelid With Long-Pulsed Nd:YAG Laser
摘要： IMPORTANCE Protective eyewear or corneal shields are recommended during cosmetic facial laser treatment. OBJECTIVE To describe the occurrence of corneal inlay damage following treatment to the eyelids and face with an Nd:YAG laser. DESIGN, SETTING, AND PARTICIPANTS This observational case report includes a single incident case cared for at a tertiary care center. A 58-year-old man who had undergone bilateral uncomplicated myopic laser in situ keratomileusis surgery in 2003 and corneal inlay implant in the nondominant left eye in 2013 experienced decreased visual acuity (VA) and pain in the left eye after the application of 2 passes of the Nd:YAG laser to his face and both eyelids for facial tightening. At presentation, the uncorrected VA was counting fingers OS and 20/20 OD. Slitlamp biomicroscopy showed a corneal epithelial defect overlying a deformed corneal inlay, peripheral scattered pigmentary deposits, corneal haze, and brown discoloration of the lamellar pocket of the inlay. He underwent explant of the inlay and debridement 48 hours later because of deteriorating VA and increasing corneal haze. EXPOSURE Application of long-pulsed Nd:YAG laser at 1064 nm to the middle one-third of both upper eyelids and the periorbital region in a man with a corneal inlay implant. Corneal shields were not worn during the procedure. The peak penetration depth of this laser system is approximately 4 mm. The mean (SD) thickness of the upper eyelid in Asian eyes is 1.127 (0.238) mm. MAIN OUTCOMES AND MEASURES Improvement of corneal inlay damage. RESULTS In this 58-year-old man, 3 months after the inlay explant, the intrastromal discoloration had resolved. There was still residual corneal haze, but the patient was able to achieve a best-corrected VA of 20/25 OS for distance and J3 (Snellen equivalent, 20/30) OS for near. CONCLUSIONS AND RELEVANCE Although the exact cause and effect cannot be determined from a single case, our findings suggest that a history of corneal inlay implant should be asked about prior to any long-pulsed Nd:YAG laser treatment to the periorbital skin and eyelids. Furthermore, these findings suggest that laser treatment to the eyelids should be avoided and that protective eyewear or corneal shields are recommended during cosmetic facial laser treatment in all patients.
关键词： corneal inlay damage,Nd:YAG laser,corneal shields,cosmetic laser treatment,protective eyewear
更新于2025-09-19 17:13:59