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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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[Laser Institute of America ICALEO? 2016: 35th International Congress on Applications of Lasers & Electro-Optics - San Diego, California, USA (October 16–20, 2016)] International Congress on Applications of Lasers & Electro-Optics - Experimental and numerical study on laser welding of glass using a CO2 laser and glass fiber as filler material
摘要： Automated laser welding with filler wires for bridging gaps and for connecting complex devices has been established for different metal materials. In spite of that, it is still a challenge to transfer this welding process to the brittle material glass. Therefore, glass welding is often realized through a manual process by heating the glass with a gas flame. In addition, welding of non-rotational components requires filler material for gap bridging between the joining partners, which is applied manually today. This work presents an experimental and numerical study on laser welding of fused silica using glass fiber as a filler material to bridge gaps. The goal was to achieve a defined weld penetration depth and heat affected zone which is important for the production of optical elements. Therefore, a CO2 laser heats up the glass components as well as the glass fiber within a temperature controlled welding process. The numerical investigations were used to identify the general process window for welding fused silica. Within the experimental study, the process parameters, such as the defined welding temperature, laser focal spot size, and feed rate were varied to investigate their impact on the welding outcome. In addition, the impact of the filler wire coating on the material composition of the welded component in the joint zone was investigated. Compared to the manual process, laser welding with glass fiber as a filling material leads to a highly reproducible process enabling a high automation level.
关键词： fused silica,temperature controlled welding,heat affected zone,laser welding,glass fiber,filler material,glass,CO2 laser,weld penetration depth
更新于2025-09-19 17:13:59
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Effect of Laser Quenching on the Microstructure and the Abrasive Wear Resistance of 30KhGSA Steel
摘要： The results of microstructural studies, the microhardness distribution, and the estimation of abrasive wear resistance of structural 30KhGSA steel samples hardened during continuous irradiation with a multichannel (48 beams) CO2 laser are presented. Fine martensite forms in the hardened zone and the steel has a high hardness and abrasion resistance.
关键词： abrasive wear resistance,multichannel CO2 laser,laser quenching,structural steel
更新于2025-09-19 17:13:59
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Effect of CO2 laser (10.6????m) and Remin Pro on microhardness of enamel white spot lesions
摘要： This study investigated the combined effect of CO2 laser irradiation and Remin Pro paste on microhardness of enamel white spot lesions (WSLs). Seventy-eight intact premolars were randomly assigned into six groups and then stored in a demineralizing solution to create WSLs. Afterwards, the teeth in group 6 (negative control) remained untreated, while groups 1 and 4 were exposed to CO2 laser irradiation (20 Hz, 1 W, 30 s) and Remin Pro paste, respectively. In groups 2 and 3, the teeth were exposed to laser either before (group 2) or after (group 3) Remin Pro application. The teeth in groups 1 to 5 were then immersed in artificial saliva for 90 days while subjected to fluoride mouthwash and weekly brushing. Finally, the teeth were sectioned, and Vickers microhardness was measured at the enamel surface and at 50, 100, and 150 μm from the surface. One sample of each group was also examined with scanning electron microscope (SEM). Data were analyzed by two-way analysis of variance (ANOVA) and Tukey’s test. The significance was set at 0.05. Laser irradiation followed by Remin Pro application (group 2) caused a significant increase in total WSLs’ microhardness compared with laser alone (group 1) and control groups (P < 0.05). Microhardness at depths of 100 and 150 μm was also significantly greater in group 2 compared with those of group 3 and control groups (P < 0.05). Combined application of CO2 laser with Remin Pro paste, when laser is irradiated before the paste, is suggested for re-hardening of WSLs in deep layers of enamel.
关键词： Tooth remineralization,White spots,CO2 laser
更新于2025-09-19 17:13:59
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Surface Properties of Beech Wood after CO2 Laser Engraving
摘要： The paper deals with the properties of a beech wood surface treated by CO2 laser engraving. The studied concerns were the discoloration, changes to morphology assessed through roughness and waviness parameters, and surface wetting with standard liquids (water and diiodomethane), with the aim of determining the wood surface free energy. The results have confirmed that the studied properties of the beech wood surface varied significantly, which were affected by the laser beam power P and raster density n. With increasing P and n, the lightness L* (expressed in CIE L*a*b* color space) decreased significantly. We also observed significant variation in the color coordinates a* and b*. At 8% laser power, the roughness and waviness parameters measured parallel as well as perpendicular to the grain increased proportionally with the increasing raster density. However, 4% laser power was not associated with distinct changes. Increasing the raster density reduced beech wood surface wetting equally with water and with diiodomethane. This was reflected in the higher contact angle values. The wood surface exhibited higher hydrophobicity at 4% laser power. At this power, the increasing raster density was reflected in the decreasing surface free energy, due to its polar component decrease. At 8% laser power, the changes in surface free energy were very minor from the practical viewpoint. The results suggest a potential good adhesion between film-forming materials and wood. However, the gluing performance may be negatively affected by the high roughness attained at 8% laser power and at higher raster densities.
关键词： color,wetting,surface properties,CO2 laser,roughness,contact angle,beech wood,surface free energy
更新于2025-09-19 17:13:59
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A fibered near-infrared laser heterodyne radiometer for simultaneous remote sensing of atmospheric CO2 and CH4
摘要： The performance of an all fibered near-infrared laser heterodyne radiometer (NIR-LHR) is demonstrated in ground-based solar occultation mode. A 1 × 2 fiber optical switch is employed as an alternative modulator to traditional chopper, which makes the system more stable and compact. Two distribute feedback (DFB) lasers centered at 1.6 μm and 1.65 μm, are employed as local oscillators to probe absorption lines of CO2 and CH4, respectively. After data processing and retrieval, column-averaged abundances and the mixing ratio of atmospheric CO2 and CH4 are determined based on the measurement of over six months in our laboratory (Hefei, China, 31.9°N 117.16°E). Finally, the results are validated by comparison with the GOSAT results during the same time period. The reported all fibered laser heterodyne radiometer in this manuscript has great potential to be a portable and high spectral resolution instrument for atmospheric remote sensing of multi-component gases.
关键词： Atmospheric remote sensing,CO2,Laser heterodyne radiometer,Near-infrared,CH4
更新于2025-09-19 17:13:59
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Excellent quality microchannels for rapid microdevice prototyping: direct CO2 laser writing with efficient chemical postprocessing
摘要： Rapid, simple microchannel prototyping is critical for the development of modern microfluidic devices and platforms. Laser cutting (ablation) using a commercially available continuous wave (CW) CO2 laser followed by thermal bonding is one of the most common approaches for prototyping in thermoplastics such as polymethyl methacrylate (PMMA). However, this technique suffers from poorly controlled channel quality, inconsistent results from solvent-based post-processing, and inconsistency of thermal bonding. We have overcome these challenges through a systematic study of channel ablation in PMMA using a CW CO2 laser. A new solvent treatment approach results in clearly improved microchannel quality and processing consistency, with negligible residual solvent. Thermal bonding of the processed material showed fourfold increase in bonding strength with full retention of PMMA’s favourable optical clarity. As proof of concept, a high-quality three-layered microfluidic prototype is fabricated with this new method and its performance demonstrated.
关键词： CO2 laser,Microfluidics,Nanofluidics,Thermal bonding,Solvent treatment,PMMA
更新于2025-09-19 17:13:59
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Development of a novel sheathless CE-ESI-MS interface via a CO2 laser ablated opening
摘要： A new and easy to construct sheathless capillary electrophoresis electro spray ionization mass spectrometry (CE-ESI-MS) interface was developed that offers several advantages compared to traditional liquid junction interfaces. The fabrication of the device only requires a CO2 laser engraver that most groups working with microfluids have access to. It only takes a few seconds to create a CO2 laser ablated opening in the bare-fused silica capillaries and the opening can be placed as close as a few mm from the spray tip. The capillary is punctured through a silicone tube such that the opening is directly placed inside this tube, which also serves as a liquid reservoir for the make-up liquid. Electrical contact required for both CE separation and ESI is established via the liquid in this reservoir which is in contact with the electrode of an external high voltage power supply. The developed CE-ESI-MS interface is capable of analysing both small molecules and biomolecules such as peptides in physisorbed PEG polymer brush coated capillaries. Proof-of-principle of the interface was demonstrated by analysing a tryptic digest of BSA. Further, a range of drugs of abuse were also investigated. The examined small molecules (pethidine, nortriptyline, methadone, haloperidol and loperamide) have a quantification limit (LOQ) of 150 ng/mL and a detection limit (LOD) of 40 ng/mL (except for loperamide: LOD = 80 ng/mL). Finally, we used our novel CE-MS interface for the analysis of the Aβ40 peptide. This is a member of the beta-Amyloid peptide family, involved in the development of Alzheimer's disease. A LOQ of 9 μg/mL was obtained for Aβ40, corresponding to 23 fmoles in a sample volume of 11 nL.
关键词： Mass spectrometry,Aβ40,CO2 laser,Sheathless interface,Capillary electrophoresis
更新于2025-09-19 17:13:59
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Mid-term evaluation of perioperative i.v. corticosteroid treatment efficacy on overall and audiological outcome following CO2 laser stapedotomy: a retrospective study of 84 cases
摘要： Purpose Our aim was to determine whether perioperatively administered corticosteroid treatment has any beneficial effect on the outcome of stapes surgery, with special regard to the audiological results and early postoperative morbidity. Methods 84 CO2 laser stapedotomies performed in our institute between 2013 and 2018 were included in our investigation. All cases underwent preoperative and mid-term postoperative pure-tone audiometric evaluation. Vestibular complications were also evaluated. The cases were subdivided into two groups, 23 patients received perioperative i.v. methylprednisolone treatment (“S”) while the other 61 patients (“nS”) did not receive any adjuvant pharmacological therapy. The data were analyzed retrospectively using IBM SPSS Statistics. Results CO2 laser stapedotomy proved to be a successful intervention with a significant improvement in ABG and AC thresholds as well. Long-term BC levels were significantly better compared to preoperative ones in the S group; however, in the nS group, no difference could be shown. Hearing and ABG gain were significantly superior in group S [28.1?dB (SD11.2) vs. 18.1?dB (SD 10.9) and 23.9?dB(SD 9.8) vs. 17.2?dB (SD 9.5), respectively]. Conclusion No significant inner ear damage was detectable in the results of our CO2 laser stapedotomy method; however, the positive effect of corticosteroid treatment could be demonstrated through the postoperative hearing levels. We found no statistical difference in early postoperative morbidity. According to our data, the routine administration of corticosteroids during stapes surgery could be an issue worthy of consideration. The effects of perioperative treatment vs that on the first day after surgery, and topical vs. systemic treatment could be the subject of further investigation in a prospective manner.
关键词： Middle ear,Stapes surgery,Otosclerosis,Stapedotomy,Corticosteroid therapy,Audiology,CO2 laser
更新于2025-09-19 17:13:59
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Effect of rescue fractional microablative CO2 laser on symptoms and sexual dysfunction in women affected by vulvar lichen sclerosus resistant to long-term use of topic corticosteroid
摘要： Objective: The objective of this study was to evaluate the efficacy of rescue fractional microablative CO2 laser treatment in women with severe symptoms and sexual dysfunction related to lichen sclerosus not responsive to long-term ultra-potent topical corticosteroid treatment. Methods: Consecutive eligible women with lichen sclerosus referred to our unit who received fractional microablative CO2 laser treatment after failure of ultra-potent topical corticosteroid treatment were enrolled in the study. The diagnosis was confirmed by histological assessment in all cases. Patients underwent two cycles of CO2 laser every 30 to 40 days. The severity of lichen sclerosus-related symptoms, sexual function, and procedure discomfort were evaluated with a visual analog scale in the same individual at baseline, after completion of each treatment cycle. Follow-up visits were scheduled during each treatment cycle and at least 1 month after completion of the treatment. The Friedman ANOVA test was used to evaluate differences in the visual analog scale scores of each symptom during treatment. Results: A total of 100 patients with vulvar lichen sclerosus were screened, 40 of whom fulfilled the eligibility criteria. We found a significant improvement in vulvar itching (x2 [2] ? 31,182, P < 0.001), vulvar dryness (x2 [2] ? 40,364, P < 0.001), superficial dyspareunia (x2 [2] ? 37,488, P < 0.001), and sensitivity during intercourse (x2 [2] ? 22,143, P < 0.001) after two CO2 laser cycles. Pain related to probe movement and laser application was low and did not change significantly consequent to treatment. No systemic or local adverse effects occurred during or after laser treatment. Conclusion: Fractional microablative CO2 laser treatment is safe and might represent an effective rescue procedure for patients suffering from lichen sclerosus who fail to respond to long-term ultra-potent topical corticosteroid treatment. These preliminary findings require further study with adequately powered randomized controlled trials.
关键词： Lichen sclerosus,Topical steroids,Lichen,Vulvar disorders,CO2 laser
更新于2025-09-19 17:13:59