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Laser‐Assisted Strain Engineering of Thin Elastomer Films to Form Variable Wavy Substrates for Cell Culture
摘要： Endothelial and epithelial cells usually grow on a curved environment, at the surface of organs, which many techniques have tried to reproduce. Here a simple method is proposed to control curvature of the substrate. Prestrained thin elastomer films are treated by infrared laser irradiation in order to rigidify the surface of the film. Wrinkled morphologies are produced upon stress relaxation for irradiation doses above a critical value. Wrinkle wavelength and depth are controlled by the prestrain, the laser power, and the speed at which the laser scans the film surface. Stretching of elastomer substrates with a “sand clock”-width profile enables the generation of a stress gradient, which results in patterns of wrinkles with a depth gradient. Thus, different combinations of topography changes on the same substrate can be generated. The wavelength and the depth of the wrinkles, which have the characteristic values within a range of several tens of μm, can be dynamically regulated by the substrate reversible stretching. It is shown that these anisotropic features are efficient substrates to control polarization of cell shapes and orientation of their migration. With this approach a flexible tool is provided for a wide range of applications in cell biophysics studies.
关键词： cell curvotaxis,laser treatment,curvature,dynamic substrates,strain engineering
更新于2025-11-21 11:08:12
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Laser Treatment for Melanin Gingival Pigmentations: A Comparison Study for 3 Laser Wavelengths 2780, 940, and 445a??nm
摘要： The normal appearance of the gingiva is pink to light red, and this appearance may change due to many factors and might be noticeable causing aesthetic concerns. In the Gulf area, the gingival melanin pigmentation is of the main type of concern, and patients expect the pigmentation to be removed for aesthetic reasons. Many techniques have been used to remove the melanin pigmentation such as using surgical blades, diamond or ceramic burs, chemicals, and lasers. This study is comparing the results of three lasers (Er, Cr, YSGG 2780 nm, Diode 940 nm, and 445 nm) in the removal of melanin gingival depigmentation. Clinical outcome parameters including bleeding, wound healing, pain, duration of procedure, color improvement, patient satisfaction, and relapse rate after 2 years were assessed. Conclusion. Within the limitation of this study, all three wavelengths were fast, e?ective in peeling the pigmentations and well tolerated by the patients. The esthetical results were excellent, and the patients were highly satis?ed. Suggestion. To have a bigger number of samples in future papers, and histological studies might be included to explore the di?erent impacts of each wavelength on the gingival melanin pigmentation speci?cally and on the gingival tissue generally.
关键词： aesthetic dentistry,Cr,445 nm,YSGG 2780 nm,laser treatment,Diode 940 nm,Er,melanin gingival pigmentations
更新于2025-09-23 15:21:01
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Deep sedation for laser treatment of cutaneous vascular anomalies in children
摘要： Pulse laser treatment is useful for aesthetic improvement in children with capillary vascular malformation and residual superficial haemangiomas. However, pulse laser treatment is painful, and repeated procedures are usually required to achieve a satisfactory clinical result. Evidence shows that analgesia in children undergoing pulse laser treatment may vary from general anaesthesia to no treatment at all. This report describes our institutional experience with deep sedation in children with capillary vascular malformation, undergoing laser pulse treatment.
关键词： Procedural sedation,Pulse laser treatment,Children,Analgesia
更新于2025-09-23 15:21:01
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Laser Treatment of Accidental Tattoos: Experience at a Tertiary Referral Center
摘要： Background: To date, information on laser treatment of accidental tattoos is limited. Objectives: This study analyzes the efficacy and safety of quality-switched ruby, quality-switched Nd:YAG and picosecond lasers in the treatment of accidental hyperpigmentation in a larger patient cohort. To date, there is limited information on laser therapy of accidental hyperpigmentation. Methods: We conducted a retrospective systematic single-center analysis on 70 patients, which presented with accidental hyperpigmentation at the Dermatology Department of the University Hospital of Zurich between 2008 and 2017. Patients with accidental tattoos due to road injuries, explosives or other traumas and iatrogenic measures were included. We analyzed the data including laser parameters such as wavelength, energy density, spot size and intervals between the sessions. Also, the number of sessions performed and the overall success were registered. Results: We treated 38 patients by quality-switched nano- and/or picosecond laser therapy and completed the treatment in 28 cases within a mean number of 3–5 laser sessions. No complications occurred. Conclusion: We demonstrate the validity and safety of quality-switched and picosecond lasers in the treatment of accidental hyperpigmentation. Using a combination of different wavelengths and pulse lengths on the same lesion and gradually increasing the fluence in the course of the laser treatment is recommendable to increase efficacy. We observed a tendency towards faster elimination of facial accidental tattoos and/or originating from road injuries compared to tattoos located on the extremities and those caused by explosions, piercings or iatrogenic measures or consisting of metal pigment particles.
关键词： Laser treatment,Tattoo pigment,Surgical techniques,Dermatologic surgery
更新于2025-09-23 15:21:01
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Nodular Classic Kaposi's Sarcoma Treated With Neodymium-Doped Yttrium Aluminum Garnet Laser Delivered Through a Tilted Angle: Outcome and 12-Month Follow Up
摘要： Background and Objectives: Classic Kaposi's sarcoma (KS) is a multifocal angioproliferative disorder with a long and indolent course typically affecting the lower extremities of elderly men. Multiple nodules with a rapid growth may sometimes develop, causing pain, bleeding, and discomfort on walking. In such cases, immediate intervention using different methods, including laser therapy, is advisable. We report our experience in classic KS patients with the use of neodymium‐doped yttrium aluminum garnet (Nd:YAG) laser delivered through a tilted angle. Study Design/Materials and Methods: A total of 81 KS nodules (0.5–3 cm size) located in the feet or lower limbs of nine patients (mean age: 78.8 years; age range: 64–86 years) were selected for treatment with Nd:YAG laser (5–7 mm spot, 140–200 J/cm2 fluence, 5 ms triple pulse with 10 ms delay). The laser beam was delivered at the periphery of each nodule using a tilted angle of 30° to 60° according to lesion size in order to better target the feeding vessels located in the inner and basal depth of the lesion and minimize tissue damage. The treatment outcome was evaluated by clinical photograph, videodermatoscopy, and ultrasound scanning performed before and after treatment, and at each monthly follow‐up visit. Results: All treated patients showed full recovery, with negligible scarring, no residual hyperpigmentation, and complete regression of pain. Treatment discomfort was minimal and use of topical anesthetics was not needed. No recurrences were observed at 12‐month follow up. Conclusions: Long‐pulse Nd:YAG laser delivered using a tilted angle is a fast, easy, effective, comfortable, and safe treatment option available to promptly shrink bulky, painful, or bleeding nodules with minimal discomfort and gives excellent functional and cosmetic results.
关键词： laser treatment,Nd:YAG,classic Kaposi's sarcoma
更新于2025-09-23 15:21:01
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The impact of laser surface treatment on the microstructure, wear resistance and hardness of the AlMg5 aluminum alloy
摘要： Light metal alloys due to several unique properties such as low density and high corrosion resistance are increasingly used in various technical applications, where the automotive industry is one of the most important sectors. The automotive applications use mostly aluminum alloys, where the strength to density ratio of the material plays a crucial factor. Unfortunately, relatively low mechanical properties limit their applications for parts where a high surface hardness and wear resistance is expected. The classic heat treatment of aluminum alloys can only in some limited ranges improve the bulk material properties. Despite this, surface treatment with laser processing has developed significantly over the past 20 years. The laser beam treatment allows the introduction of a wide range of alloying elements to the surface layer of an aluminum alloy and thus, as a result of the precipitation of numerous intermetallic phases, significantly increases hardness, and abrasion resistance. The purpose of this work was to modify the aluminum surface layer using high-power fiber laser (HPFL). During this process, a mixture of titanium and iron powders (90/10 wt.%) was introduced onto the surface of the AlMg5 alloy. The microhardness tests carried out by the Vickers method and tribological tests showed a significant increase in mechanical properties in the entire volume of the obtained layer. Research on light and scanning microscopy revealed fragmentation of primary precipitates and the formation of numerous intermetallic phases rich in titanium and aluminum.
关键词： Aluminium alloy,Laser treatment,EDS analysis,Tribological properties,High power fibre laser
更新于2025-09-23 15:19:57
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Correlation between laser energetic parameters and magnetic properties of GO laminations under surface treatments with long, short or ultra-short pulsed lasers
摘要： Electromagnetic components mostly incorporate soft magnetic materials used as flux multipliers. Hence, any reduction in iron loss of the magnetic core yields in saving energy. Among the techniques, the local laser treatment is a non-contact method applied for 180° domain refinement (Patri et al. [1]). The present study reassessed the impact of laser treatment on the magnetic properties of grain oriented silicon steels. Various laser pulse widths are used: an ultra-short pulse laser mainly adapted to the ablation process and a long and short pulse durations used for both irradiation and scribing processes [2]. The power loss is measured with a Single Sheet Tester (150 × 150 mm2). Each type of treatment resulted in a power loss reduction of 15–35% at peak induction 1.5 T and frequency 50 Hz. However, only the scribing and the ablation improved also the apparent permeability. In this work, the laser energy parameters are used to estimate the laser impact on the heat affected zone, the groove depth, the induced thermal stress, and on the internal properties of a magnetic behavioral model: static permeability and dynamic magnetization property [3].
关键词： Groove depth,Heat affected zone,GO laminations,Induced thermal stress,Laser treatment,Magnetic properties
更新于2025-09-23 15:19:57
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Grain refinement in laser remelted Mg-3Nd-1Gd-0.5Zr alloy
摘要： Columnar grains are normally favoured with the high cooling rate and steep thermal gradient in laser-based additive manufacturing. Here, we demonstrate that ?ne, fully equiaxed grains can be achieved in Mg-3Nd-1Gd-0.5Zr (EV31) alloy by laser surface remelting. The grains in the melt pool are remarkably re?ned from 74 μm to 3.5 μm, which can be attributed to the growth restriction effect, i.e. the constitutional supercooling formed by Zr solute during solidi?cation in combination with the high cooling rate imposed by laser surface remelting. This novel ?nding could be applied for the control of grain morphology and alloy design for additive manufacturing applications.
关键词： Solidi?cation microstructure,Grain re?ning,Laser treatment,Magnesium alloys,Rapid solidi?cation
更新于2025-09-23 15:19:57
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Successful and quick treatment of nevus of Ota with 755nm picosecond laser in Chinese
摘要： Nevus of Ota, also known as nevus fusco-caeruleus ophthalmo-maxillaris, is a benign dermal melanocytosis. In the past, this disease was usually treated by Q-switched laser therapy, but the course of treatment was relatively long. In recent years, it has been reported that 755nm picosecond laser, which was firstly reported to treat tattoos, is also effective in the treatment of nevus of Ota. Here, we report six cases of nevus of Ota which were treated with 755nm picosecond laser in Chinese people. We find amazingly that these lesions almost disappeared after only one or two sessions of treatment.
关键词： 755nm picosecond laser,treatment,nevus of Ota
更新于2025-09-23 15:19:57
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Determination of the limiting values of the laser parameters to heat treatment of powder carbon steels surface
摘要： The microstructure and microhardness of the surface layer of powder steels PA-ZhGr with different porosity are studied in comparison with cast steel U10 after laser treatment (LT) with a 1 kW fiber laser in argon. Using thermal modeling, the geometric dimensions of the laser exposure zones formed in the area of the laser exposure were calculated and experimentally confirmed, and the mechanisms of their formation were proposed. The boundary values of the integral criterion for the parameters of laser influence for the heat treatment of carbon powder steels are established.
关键词： thermal modeling,microstructure,laser treatment,microhardness,powder steels
更新于2025-09-23 15:19:57