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Electrostatically Directed Assembly of Nanostructured Composites for Enhanced Photocatalysis
摘要： It is well established that the activity of photocatalysts can be improved by deposition of redox catalysts, which can effectively extract the photogenerated charge carriers, enhance the rate of interfacial reactions, and thus suppress undesired recombination processes. For optimum performance, a high degree of control over the loading, size, and surface catalytic properties of redox catalyst particles is desirable. Herein, a novel, highly controllable, and versatile method for preparation of TiO2 catalyst composites is reported. It starts with the generation of “naked” (ligand-free) nanoparticles of CuOx or FeOx by pulsed laser ablation of metal oxide targets in water. In the next step, a nearly quantitative colloidal deposition of CuOx and FeOx nanoparticles onto anatase TiO2 substrate is achieved by adjusting the pH in order to establish electrostatic attraction between the colloids and the substrate. The resulting TiO2–CuOx and TiO2–FeOx assemblies with optimum catalyst amount (≈0.5 wt%) exhibit photocatalytic rates in degradation of 2,4-dichlorophenoxyacetic acid enhanced by a factor of ≈1.5 as compared to pristine TiO2 under simulated solar irradiation. The electrostatically directed assembly of TiO2 with ligand-free catalyst nanoparticles generated by pulsed laser ablation is thus demonstrated as a viable tool for preparation of composites with enhanced photocatalytic performance.
关键词： photocatalysis,titanium dioxide,laser ablation,colloidal deposition,nanoparticles
更新于2025-09-23 15:23:52
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Equine Surgery || Lasers in Veterinary Surgery
摘要： Surgical lasers facilitate minimally invasive surgery, allow surgical access to otherwise inaccessible areas, and induce tissue interactions, which cannot be obtained with conventional surgical instrumentation. Surgical laser procedures can be performed on an outpatient basis and have eliminated procedures that previously required general anesthesia and hospitalization. Surgeons should be knowledgeable about which procedures can be accomplished with surgical lasers and which are better suited to conventional surgery. This chapter will provide information and guidelines on the use of surgical lasers in equine surgery.
关键词： equine surgery,minimally invasive surgery,carbon dioxide laser,Surgical lasers,neodymium:yttrium-aluminum-garnet laser,holmium:yttrium-aluminum-garnet laser,diode laser
更新于2025-09-23 15:21:01
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Clinical and Histological Assessment of Combined Fractional CO <sub/>2</sub> Laser and Growth Factors Versus Fractional CO <sub/>2</sub> Laser Alone in the Treatment of Facial Mature Burn Scars: A Pilot Splita??Face Study
摘要： Background and Objectives: To investigate the therapeutic efficacy and safety of growth factors combined with fractional carbon dioxide (CO2) laser in comparison with fractional CO2 alone in a sample of patients with facial mature burn scars. Study Design/Materials and Methods: Fifteen Egyptian patients with bilateral facial burn scars were treated with six sessions of fractional CO2 laser at 6‐week intervals. Following each laser session, a topical growth factors cocktail was applied to one side of the face in a split‐face manner. Clinical evaluation by Vancouver Scar Scale (VSS), Patient and Observer Scar Assessment Scale (PSOS), and photography before and 2 months after the last laser session was done. Three millimeter punch biopsies were obtained from each side of the face pre‐ and 1‐month post-treatment to measure the mean area percent of collagen. Results: Posttreatment, both VSS and PSOS scores decreased on both sides of the face being more significant on the growth factors treated side, showing more scar pliability and shorter downtime (P = 0.001). A significant difference in the mean area percent of collagen was also noted on both sides. Conclusion: Adding topical growth factors to fractional CO2 laser treatments is effective and safe with better results as regards scar pliability and shorter downtime than fractional CO2 laser alone.
关键词： growth factors,burn,fractional carbon dioxide laser
更新于2025-09-23 15:19:57
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Reflectance confocal microscopy-guided carbon dioxide laser ablation of low-risk basal cell carcinomas: A prospective study
摘要： Background: Basal cell carcinoma (BCC) treatment modalities can be strati?ed by tumor subtype and recurrence risk. The main limitation of nonsurgical treatment modalities is the lack of histopathologic con?rmation. Re?ectance confocal microscopy (RCM) is a noninvasive imaging device that provides quasihistologic images. Objective: To evaluate the feasibility and ef?cacy of RCM-guided carbon dioxide (CO2) laser ablation of low-risk BCCs. Methods: Prospective study with biopsy specimeneproven low-risk BCCs imaged with RCM. RCM was performed on these sites before and after ablation. If residual tumor was found, a new series of laser passes were performed. The patients were then monitored for recurrence clinically and with RCM. Results: Twenty-two tumor sites in 9 patients (5 men, 4 women) were imaged and treated. Median age was 59 6 12.9 years (range, 30-74 years). Mean tumor size was 7.7 mm (range, 5-10 mm). Residual tumor was identi?ed in 5 of 22 cases (22.7%) under RCM on immediate ?rst-pass postablation sites, prompting additional laser passes. Median follow-up was 28.5 months (range, 22-32 months) with no recurrences found. Conclusions: Addition of RCM to laser ablation work?ow can detect subclinical persistent tumor after initial ablation and may serve as an aid to increase the ef?cacy of laser ablation.
关键词： laser,basal cell carcinoma,carbon dioxide laser,ablation,diagnosis,follow-up,re?ectance confocal microscopy,treatment
更新于2025-09-19 17:13:59
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Severe Rhinophyma. Tips and Tricks in Carbon Dioxide Laser Decortication
摘要： Severe rhinophyma may result on marked facial disfigurement, psychosocial disability and functional impairment. Although there is a wide range of treatment approaches, CO2 laser decortication allows prompt removal of the hypertrophic tissue while preserving the original nose shape and skin surface texture.
关键词： rosacea,laser treatment,laser decortication,surgery,rhinophyma,dioxide laser
更新于2025-09-12 10:27:22
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Treatment of Congenital Melanocytic Nevi in the Eyelid and Periorbital Region With Ablative Lasers
摘要： Background: Congenital melanocytic nevi (CMN) that occur on the eyelid and periorbital region cause cosmetic disfiguring. Laser treatment has aroused interest as an alternative treatment method, and resurfacing lasers have shown promising results. Objective: This study aimed to evaluate the efficacy and safety of carbon dioxide laser and erbium:yttrium aluminum garnet laser to treat CMN of the eyelid and periorbital region. Methods and Materials: Twenty patients with CMN were included in this study and were treated with either the CO2 or erbium:yttrium aluminum garnet laser. Clinical efficacy outcomes were evaluated by visual assessment and L*a*b* color space evaluation at least 6 months after treatment. Results: The average (SD) visual evaluation improvement, assessed on a 5-point scale, was 2.8 (1.27). The mean (SD) values of the relative L* improvement rate and blanching rate of the CMN lesion were 32.0% (47.9%) and 34.1% (36.2%), respectively. Spearman rank correlation coefficient between the objective and subjective evaluations was significant (P < 0.001). Three cases developed partial hypopigmentation. No patient developed hypertrophic scars. Conclusion: The outcomes after laser treatment were variable, although half of the patients achieved greater than 50% clearance. It provides an alternative to surgical excision for the removal of CMN in the difficult regions. Surgery excision is inevitable for some patients.
关键词： carbon dioxide laser,eyelid and periorbital region,congenital melanocytic nevi,ablative laser,Erbium:YAG laser
更新于2025-09-12 10:27:22
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Laser absorption spectroscopy of rare and doubly-substituted carbon dioxide isotopologues
摘要： Unambiguous detection of the clumped carbon dioxide isotopologue 13C16O18O with isotope ratio mass spectrometry is difficult due to isobaric interference on m/z = 47. We present an analytical technique based on direct absorption laser spectroscopy for precise, direct and simultaneous detection of all isotopologues involved in the isotope exchange reaction 12C16O2 + 13C16O18O ? 12C16O18O +13C16O2 and of 12C16O17O. The achieved precision of 2×10-5 for the 13C16O18O/13C16O2 and 12C16O18O/12C16O2 isotopologue ratios allows to determine the equilibrium constant K of the isotope exchange reaction with an external reproducibility of better than 2×10-5 (1σ) after 9 reference-sample comparisons. Each comparison requires 7 minutes. The isotopic composition of the pure gas can be simultaneously analyzed with a precision of 0.05‰ (1σ) for δ13C and δ18O, and 0.15‰ (1σ) for δ17O. The instrument deploys two interband cascade lasers (ICL) with center wavelengths of 4.3 μm and 4.4 μm. A custom-built optical cell has been designed for single pass and multi pass optical paths (pathlength ratio 1:100); it allows simultaneous detection of rare and abundant isotopologues. The setup is capable to analyze pure CO2 samples of ～100 μmol.
关键词： clumped isotope analysis,mid-IR lasers,tunable lasers,doubly substituted isotopologues,carbon dioxide,laser spectroscopy,laser absorption
更新于2025-09-12 10:27:22
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Utility of High Intensity Laser Therapy Combined with Photobiomodulation Therapy for Socket Preservation After Tooth Extraction
摘要： Objective: High intensity laser therapy (HILT) combined with photobiomodulation therapy (PBMT) using a diode or CO2 laser was administered after extraction of the left ?rst molar in rats. Effects on socket preservation (preservation of the alveolar bone and healing time after extraction) were evaluated histopathologically. Background: Irradiation using a diode or CO2 laser has been shown to hasten wound healing, but the effects remain controversial. Methods: Five-week-old male Wistar rats that underwent extraction of the left maxillary ?rst molar were divided into three groups: diode laser irradiation (diode group), CO2 laser irradiation (CO2 group), and no laser irradiation (control group). HILT (27 J) was performed immediately after tooth extraction to enhance blood coagulation, followed by PBMT (0.7 J) 1 day later to enhance healing. Tissues, including the extraction socket, were removed en bloc 3, 5, 7, 10, and 21 days postextraction to determine the morphological characteristics of wound healing and the distribution of myo?broblasts involved in scar formation. Results: In the diode and CO2 groups, new bone formation and cancellous bone maturation were observed at an early stage of wound healing. The number of myo?broblasts was signi?cantly lower in the laser treatment groups than the control ( p < 0.001), and both treatment groups had a signi?cantly higher alveolar crest height ( p < 0.01), with almost no concavity in the mucosa of the extraction wound. Conclusions: Combined HILT and PBMT following tooth extraction hastened wound healing and preserved alveolar crest height, suggesting a role in socket preservation.
关键词： myo?broblast,carbon dioxide laser,diode laser,socket preservation,tooth extraction,scar tissue,enhanced healing process
更新于2025-09-12 10:27:22
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<i>Ab initio</i> study of temperature- and laser-induced phase transitions in
摘要： We analyze the bulk phase transitions of the three titanium dioxide polymorphs anatase, rutile, and brookite in thermodynamical equilibrium and after ultrafast laser excitation using the generalized solid-state nudged elastic band (G-SSNEB) method. For calculating the forces and stresses needed for G-SSNEB, we use electronic-temperature dependent density functional theory calculations. Our results show that the anatase-rutile and brookite-rutile phase transitions have a considerably lower energy barrier than the anatase-brookite phase transition in the thermodynamical equilibrium and upon laser excitation. The obtained transition temperatures in thermodynamical equilibrium are consistent with experimentally observed ones. Furthermore, our calculations show that the pathways of the phase transition are not affected considerably by the applied laser pulse. Although the pathways do not change considerably we see that the rutile phase is stabilized by the laser pulse.
关键词： phase transitions,density functional theory,G-SSNEB method,titanium dioxide,laser excitation
更新于2025-09-12 10:27:22
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Efficacy of fractional carbon dioxide laser therapy for burn scars: a meta-analysis
摘要： Background: The present study evaluates the effectiveness of fractional carbon dioxide (CO2) laser for the treatment of burn scars. Method: Literature search was conducted in electronic databases and studies were selected by following pre-determined eligibility criteria. Random effect meta-analyses were performed to achieve the effect size of the changes (mean difference (MD) between post-treatment and pretreatment values) in selected scar assessment scale scores and other important outcome measures. Results: 14 studies were included. Treatment of burn scars with fractional CO2 laser significantly improved Vancouver Scar Scale (MD (cid:1)3.01 [95% confidence interval (CI) (cid:1)3.79, (cid:1)2.22]; p ? .00001), Patient and Observer Scar Assessment Scale (POSAS)– Patient (MD (cid:1)14.38 [95% CI (cid:1)17.62, (cid:1)11.13]; p ? .00001, POSAS – Observer (MD (cid:1)8.81 [9% CI (cid:1)11.60, (cid:1)6.02]; p ? .00001 and Scar Assessment Scale (MD 1.64 [95% CI 0.49, 2.78]; p ? .005) scores especially with regards to pigmentation, vascularity, pliability, and height of scar. Pain and pruritis also improved with this treatment. Scar thickness measured with ultrasonography decreased non-significantly (MD (cid:1)0.48 [95% CI (cid:1)1.04, 0.09]; p ? .1) whereas cutometer measures, R0 (scar firmness) and R2 (scar elasticity) did not change meaningfully. Conclusion: Fractional CO2 laser therapy is a valuable tool for the treatment of burn scars which has potential for reducing scar severity.
关键词： keloidal,hypertrophic,Burn scars,fractional carbon dioxide laser
更新于2025-09-12 10:27:22