CO2 Laser Research Articles

Inferior Rectus Muscle Thermal Injury Following Transconjunctival Blepharoplasty Using Carbon Dioxide Laser.

A 56-year-old woman was referred to the authors' hospital after the removal of the lower eyelid fat through a transconjunctival approach using a carbon dioxide laser. The patient was noted to have vertical diplopia in the primary position, with worsening diplopia on downgaze. Detachment of the right inferior rectus (IR) muscle from its insertion point was observed during exploratory surgery. The thermally damaged IR muscle fibers were attached to a location posterior to the original insertion point. At 6 months postoperatively, 8 prism diopters of right hypertropia in the primary position and a -3 degrees limitation on downgaze were still present. The patient underwent the vertical transposition of the lateral and medial rectus muscles to the IR muscle. After strabismus surgery, orthotropia was observed with no vertical diplopia in the primary gaze, but ocular motility limitation on the downgaze has permanently remained.

A comparative study on the efficacy of different treatment methods for preventing vocal cord adhesion after laser treatment for glottic cancer

Objective:Comparing the primary tumor control, vocal function recovery, postoperative adhesion rate and degree of adhesion in early glottic cancer involving the anterior commissure treated with CO₂ laser staged and lateral surgery, one-stage surgery combined with laryngeal stent placement, and simple CO₂ laser excision. Methods:This study focuses on 83 patients with T1-2N0M0 stage glottic squamous cell carcinoma involving the anterior commissure who underwent CO₂ laser treatment. The study was divided into three groups: Group A with 15 cases, treated with staged resection surgery; Group B with 18 cases, treated with one-stage surgery combined with the placement of a silicone laryngeal stent; and Group C with 50 cases, treated with simple CO₂ laser excision. The Voice Handicap Index-10（VHI-10）, the GRBAS auditory-perceptual assessment, and the maximum phonation time（MPT） were used to evaluate the vocal function of the patients before and six months after surgery. The degree of vocal cord adhesion was assessed using the Cohen classification of vocal cord adhesion. Statistical analysis was performed to determine the differences in each indicator before and after surgery, and the primary tumor control rates among the three groups. Results:Local recurrence occurred in 1 case each in Groups A and B, and in 4 cases in Group C, with no distant metastasis observed. Postoperative vocal cord adhesion of varying degrees occurred in a total of 77 cases, with an adhesion rate of 73.3%（11/15） in Group A, 88.9%（16/18） in Group B, and 100%（50/50） in Group C. The postoperative vocal cord adhesion rate and degree in Group C were significantly higher than in Groups A and B. The postoperative VHI-10 scores in all three groups were significantly increased compared to preoperative scores（P<0.05）, and when compared between groups postoperatively, Group C was significantly worse than Groups A and B （P<0.05）. The postoperative maximum phonation time（MPT） in Group C was significantly reduced compared to preoperative and was markedly shorter than that of Groups A and B postoperatively（P<0.05）. The postoperative grades of G（Grade） and R（roughness） in Group C were significantly higher than preoperatively, indicating a noticeable deterioration in voice quality, and were also significantly worse than those postoperatively in Groups A and B, with all differences（P<0.05）. Conclusion:For early glottic cancer involving the anterior commissure, choosing staged surgery or one-stage surgery combined with the placement of a silicone anterior commissure laryngeal stent were better than simple laser tumor excision in terms of secondary vocal cord adhesion and voice function preservation.

Successful Microablative Fractional Carbon Dioxide Laser Therapy for Vulvar Lichen Sclerosus: A Case Report and Mini-review

Vulvar lichen sclerosus (VLS) is a chronic inflammatory skin disorder affecting the vulvar region. VLS predominantly affects women, and most cases occur after menopause. Common symptoms include itching, skin-whitening, pain, discomfort, fissures, and scarring. Treatment options include topical steroids, emollients, lifestyle modifications, regular follow-up, and surgical interventions. Carbon dioxide (CO2) laser treatment is a therapeutic option for managing lichen sclerosus. We report a case of VLS successfully treated with a fractional microablative CO2 laser. A 72-year-old female presented with a dry vagina and vulvar itching for 6 months. She visited a local medical clinic, and oral anti-itching medication and topical anti-itching ointment were administered. However, the condition did not improve, and she felt itching. She visited our outpatient department, and a pelvic examination showed bilateral labia minor, revealing a white skin color change and a hardening sensation. The patient was diagnosed with VLS. Microablative fractional CO2 laser therapy was subsequently administered. The treatment course comprised three laser therapy sessions (treatment day, 1 month, and 2 months after the first therapy). The vulvovaginal symptoms questionnaire-21 scores were 14, 6, and 2 for the first, second, and third courses of treatment, respectively. Vulvar itching improved significantly after laser treatment – no more steroid treatment needed. After 10 months of follow-up, the condition of the vulva was maintained well. Although the treatment protocol requires further exploration, CO2 laser treatment could be considered for VLS if topical steroids are ineffective.

From CO2 to Er:YAG: A Comprehensive Review of Laser Treatments for Rhinophyma.

Rhinophyma, a benign condition resulting in nasal sebaceous tissue hypertrophy, predominantly affects Caucasian males. There are numerous surgical and medical treatments for rhinophyma with varying degrees of success. This review aims to provide a comprehensive overview of ablative therapies, highlighting our preferred treatment approach. This review analyzes the evidence behind ablative lasers in treating rhinophyma, with a focus on the 10600 nm carbon dioxide (CO2) and 2940 nm erbium: yttrium-aluminum-garnet (Er:YAG). Both CO2 and Er:YAG have demonstrated efficacy in treating rhinophyma. CO2 laser ablation results in a higher incidence of scarring and hypopigmentation. Er:YAG has high water absorption, which results in less thermal damage, allowing for quicker healing and fewer complications. Management of rhinophyma can remain challenging; however, ablative lasers are an effective treatment. Both laser types have promising outcomes, each with different advantages and complications. In particular, Er:YAG presents fewer complications compared to CO2 lasers. J Drugs Dermatol. 2024;23(11):932-936. doi:10.36849/JDD.8199.

Devices for treatment of nail psoriasis.

Nail psoriasis (NP) affects a significant proportion of cutaneous psoriasis patients, often leading to functional impairment and psychosocial distress. Despite available treatment options, challenges persist in achieving efficacy and with drug delivery, prompting investigation into novel therapeutic devices. A literature search was performed using the PubMed database for devices and lasers for NP on 17 October 2023 using the following search terms: device OR laser AND "nail psoriasis." Twenty-two articles were included describing treatment with pulsed dye laser, fractional carbon dioxide (CO<inf>2</inf>) laser, long-pulsed Nd:YAG laser, excimer laser, photodynamic therapy, intense pulsed light, and microneedling device. While some recent studies on use of therapeutic devices have shown promising results for NP treatment, current evidence supports an algorithmic approach including topical therapies, intralesional kenalog injections, and systemic therapies, depending on number of nails affected, presence of psoriatic arthritis, cutaneous psoriasis, comorbidities, and effect on quality of life. Laser therapy, although promising, requires further validation through extensive randomized trials before its inclusion in treatment regimens. These exploratory findings highlight emerging therapies that may expand the spectrum of options available. Use of lasers for NP treatment could provide dermatologists with a broader arsenal for customizing treatment plans that address individual patient needs, taking into account comfort, cost, and compliance to enhance overall patient outcomes.

Evaluating the efficacy of combining fractional CO2 laser and topical tranexamic acid for burn scar and hyperpigmentation treatment: A prospective, randomized, single-blinded, split-body study

Abstract Background: A fractional carbon dioxide (CO2) laser can improve the appearance of burn scars. In addition, tranexamic acid (TXA) inhibits melanin production for whitening effects. Laser-assisted drug delivery (LADD) technology utilizes lasers to enhance the percutaneous absorption of drugs. Objectives: The purpose of this study was to investigate whether the use of a fractional CO2 laser in combination with TXA can further improve pigmentation in burn scars. Methods: This prospective, randomized, single-blinded, split-body study included patients aged 20 years and older who had burn scars with associated hyperpigmentation for more than 6 months. A total of 12 patients were included between September 1, 2019, and August 31, 2020. For each patient, their pigmented burn scar was divided into two sides along the midline. One scar side received fractional CO2 laser alone, and the other combined fractional CO2 laser and topically applied TXA solution. Treatment sessions were conducted monthly for a total of three times. Photographs were captured at baseline and 3 months after completing the 3 monthly treatment sessions. Four plastic surgeons, blinded to the treatment sides, compared the improvement on both sides of each patient based on the photographs. The patients’ reported satisfaction levels were also recorded. Results: In the physician assessments, both methods showed a noticeable improvement in scar appearance and pigmentation. On a scale of 1 to 10, physicians rated the overall improvement in scar appearance between 4.6 and 5.6 points, while the improvement in overall hyperpigmentation ranged from 6.0 to 6.9 points. The average patient satisfaction score was 8.4 ± 1.6 points. However, there was no significant difference in the improvement of outcomes between the two methods, with or without the addition of TXA treatment. Conclusion: This study shows that fractional CO2 laser treatment significantly improves burn scars and hyperpigmentation. However, adding TXA shows no clear additional benefits. Before making the final conclusion based on the results from the small patient sample size, further research is encouraged to clarify the delivery pathways in applying TXA and explore the mechanisms behind LADD.

Investigating Predictors of Decannulation Through Endoscopic Approach in Patients With Tracheostomy and Peristomal Subglottic Stenosis.

Peristomal subglottic stenosis (SGS) is a common sequela after tracheostomy, with severe cases precluding decannulation. Predictors of decannulation success in these patients following endoscopic intervention are not well studied. The aim of this study is to investigate predictors of successful decannulation and inform treatment decisions. This study is a retrospective case series of 22 adult patients presenting to the senior author with a tracheostomy and peristomal SGS precluding decannulation between 2018 and 2023. Department of Otolaryngology-Head & Neck Surgery, University of Arizona College of Medicine-Tucson. Patient demographics, relevant clinical factors, stenosis characteristics, and the number of endoscopic procedures performed were analyzed to identify predictors of successful decannulation. Endoscopic interventions were generally performed 3 months apart with CO2 laser debridement, balloon dilation, and intralesional injection of steroid, all done with a laser-safe endotracheal tube in place through the stoma. Out of the 22 patients in the study, 9 (40.9%) achieved decannulation, all through an endoscopic approach. Body mass index (BMI) and age were identified as significant negative predictors of decannulation success (P = .02; P = .05, respectively). Stenosis characteristics, such as the presence of tracheomalacia, excessive dynamic airway collapse, multilevel stenosis, posterior glottic stenosis, and anterior granulation tissue shelf did not significantly impact decannulation success. A 40.9% decannulation rate was achieved in our cohort. BMI and age were identified as negative predictors of decannulation success. Stenosis characteristics did not significantly affect decannulation outcomes. Further investigation is warranted to establish reliable predictors of decannulation.

Evaluation of the efficacy, safety and satisfaction rates of platelet-rich plasma, non-cross-linked hyaluronic acid and the combination of platelet-rich plasma and non-cross-linked hyaluronic acid in patients with burn scars treated with fractional CO2 laser: A randomized controlled clinical trial.

Skin scarring can result from burns, injuries, stretch marks and acne, leading to cosmetic and functional difficulties. Treatments for burn scars encompass a range of options, such as lasers, corticosteroid injections, surgery and regenerative techniques such as platelet-rich plasma (PRP). Hyaluronic acid-based products offer skin hydration and shield against aging effects. A study is being conducted to evaluate how effective PRP injection, hyaluronic acid and their combination improve burn scars and their effects on quality of life and potential disabilities. In our study, PRP and non-cross-linked hyaluronic acid treatments were compared in 10 individuals with burn scars between 2022 and 2023. Patients received CO2 fractional laser treatment followed by injections in scar areas. Evaluations included the Vancouver scar scale (VSS), biometric assessments, ultrasounds and satisfaction ratings. Two therapy sessions were conducted at 1-month interval, and assessments were done before treatment, 1 month after the first session, and 3 months after the first session. Biometric assessments showed significant improvements in various parameters (tewametry, corneometry, erythema index, melanin index, cutometry, thickness and density) in the intervention groups compared to the placebo group (p <0.05). PRP-non-cross-linked hyaluronic acid, PRP and non-cross-linked hyaluronic acid treatments exhibited the best clinical responses with significant differences between groups (p <0.05). Dermal thickness did not show significant improvement during treatment sessions, and changes among subjects were not significantly different. The colorimetry parameter improved in all groups except the placebo group, with no significant difference between intervention groups. The VSS significantly decreased in all treatment groups except the placebo group. PRP, non-cross-linked hyaluronic acid and especially the combination of these two treatment options are very effective in treating burn scars.

تأثير استعمال ليزر النيوديميوم ياك (Nd-YAG) على البنية الدقيقة وصلابة سطح الفولاذ AISI1012

The unique characteristics of the laser beam such as directionality, monochromaticity, and brightness make it a very important tool in the surface treatment engineering. The concentrated heat in the laser beam can be precisely directed toward the processed region on the surface. The laser beam power, beam size, and scanning velocity are easily controlled during the different processing methods. Laser surface modifications of metallic materials, such as laser surface melting, laser surface alloying, and laser cladding are some of the most important methods to improve the mechanical properties of the processed layer on the surface. A pulsed Nd-YAG laser surface melted specimens of low carbon steel with a maximum power of 90W at different processing parameters. The rapid melt and solidification of the treated layer produced a refinement in the microstructure. The original microstructure of this steel (Ferrite + Pearlite) has been transformed to new phases of martensitic and bainitic structures. The melted layer consists of the melted pool, the heat affected zone, and the substrate. The maximum hardness of the laser melted layer is more than 400 HV. The effect of different lasers such as high power CW CO2 laser on the mechanical properties and corrosion resistance of steel alloys will be carried out in future studies. Keywords: Nd-Yag Laser, Laser surface treatment, Microstructure and hardness of AISI1012 steel

Combinations of Energy-based Devices plus isotretinoin for management of acne and acne scars: A systematic review.

A 6-month interval between systemic isotretinoin (ISO) and the initiation of energy-based interventions has been recommended, due to concerns about keloid formation and delayed wound healing. While this postponement goes against the current trend of early intervention for acne scarring. This systematic review evaluates the efficacy, safety, and patient satisfaction of combinations of ISO with energy-based devices (EBD). PubMed, Embase, Web of Science, Cochrane Library, and Cochrane Central Register of Controlled Trials were comprehensively searched up to April 2023 according to PRISMA guidelines. Two independent reviewers screened the titles and abstracts to select articles. The quality of the literature was assessed for each study design. A total of 16 studies addressing the efficacy and safety of energy-based modalities combined with ISO were identified, including six randomized controlled trials (RCTs), two case series, seven cohort studies, and one case report. ISO combinations with intense pulsed light (IPL), fractional ablative CO2 laser, pulsed dye laser (PDL), non-ablative fractional laser (NAFL) and fractional microneedle radiofrequency (FMRF) have been tested for improving acne severity, acne scarring and erythema. The current evidence does not justify delaying the use of EBDs for patients who have recently undergone or are currently receiving ISO treatment. Evidence-based treatments such as PDL, NAFL, and FMRF etc. are suggested relatively safe and effective in treating acne and acne scarring.

Evaluation of the effect of endoscopic CO₂laser arytenoidectomy on re-operation for failed posterior cordotomy

Objective:To analyze the efficacy of endoscopic CO₂ laser arytenoidectomy in treating bilateral vocal cord paralysis. Methods:Ninety-five patients who underwent endoscopic CO₂ laser arytenoidectomy for bilateral vocal cord paralysis at the First Affiliated Hospital of Naval Medical University（Changhai Hospital） of Shanghai from January 2009 to December 2022 were included in this study. Among them, 59 patients underwent endoscopic CO₂ laser arytenoidectomy as their first glottic enlargement surgery（Group A）, while 36 patients, who had previously undergone two unsuccessful CO₂ laser-assisted posterior cordotomies, underwent endoscopic CO₂ laser arytenoidectomy as a subsequent surgery（Group B）. Swallowing function, electronic laryngoscopy, perceptual voice evaluation, and objective voice analysis indicators were statistically analyzed before and after surgery to evaluate clinical efficacy. Results:The extubation rate after the first surgery was 84.75% in Group A and 86.11% in Group B, with total extubation rates of 94.92% and 94.44%, respectively. There were no significant differences between the two groups in preoperative and postoperative swallowing function, glottic size, or various voice evaluation indicators（P>0.05）. Within-group comparisons showed that postoperative swallowing function, glottic closure during phonation, perceptual evaluations of G（grade of hoarseness）, A（asthenia）, and B（breathiness） significantly worsened, with increased grades. The maximum transverse diameter of the posterior glottis during inspiration significantly increased, and the VHI-10 score was significantly higher postoperatively. Jitter, shimmer, and the harmonics-to-noise ratio significantly deteriorated, and maximum phonation time significantly shortened（P<0.05）. No significant differences were observed in postoperative R（roughness） and S（strain） compared to preoperative values（P>0.05）. Conclusion:Endoscopic CO₂ laser arytenoidectomy can impair voice quality to some extent but effectively alleviates breathing difficulties in patients with bilateral vocal cord paralysis. For patients who did not achieve successful extubation with CO₂ laser-assisted posterior cordotomy, endoscopic CO₂laser arytenoidectomy is an effective reoperative method, ensuring a high extubation rate while preserving certain voice functions.

Efficacy and adverse reactions of fractional CO2 lasers for treating papular acne scars: a retrospective study of 35 patients.

Papular acne scars are a special type of acne scar, and the prevalence and treatment of this disease have rarely been reported in the literature; moreover, the prevalence of this disease is often neglected, and treatment is difficult. Our study revealed a high prevalence of this type of acne scar in the clinic and explored an effective and safe method. This retrospective study aimed to analyse the prevalence of papular acne scarring among patients attending our Dermatology Laser Clinic and evaluate the clinical efficacy of fractional CO2 lasers. We retrieved the data of 370 patients with acne scarring who visited our hospital between April 2021 and November 2022 and analysed the prevalence of papillary acne scarring among them. Among these patients, 35 underwent CO2 laser treatment using an artificial grid pattern. A total of three treatments were administered, with a two-month interval between each session. Scar assessment was conducted using the Global Scar Scale (GSS) and the Acne Scar Clinical Assessment (ECCA) scale, along with physician visual evaluation and patient satisfaction surveys, both before the first treatment and one month after the final treatment. Adverse reactions were recorded during follow-up visits after each treatment. Among the 370 patients with acne scarring, 128 exhibited papular acne scarring, resulting in a prevalence rate of 34.6%. Among them, 37.5% were male and 32.6% were female. A total of 90.6% of patients had combined other types of acne scarring, while 9.4% had papular acne scarring exclusively. Following CO2 laser grid treatment, there was a significant reduction in GSS scores and ECCA values, accompanied by a noticeable improvement in physician visual evaluation and patient satisfaction scores. Papular acne scarring has a relatively high incidence rate, and there is no significant sex difference. It often coexists with other types of acne scarring. CO2 laser treatment using an artificial grid pattern effectively improved papular acne scarring with a good safety profile.

Machining of Brittle Material Glass by CO2 Laser using Taguchi L27 Array Approach and Analysing Anova Techniques

Machining of Brittle Material Glass by CO2 Laser using Taguchi L27 Array Approach and Analysing Anova Techniques

Fabrication of asymmetric supercapacitors by laser processing of activated carbon-based electrodes produced from rice husk waste

The development of supercapacitors (SCs) by using carbon electrodes obtained from biomass waste simultaneously promotes the optimized use of the renewable energy by its high-powered storage, and the reduction of contamination in nature. Such industrial sector would be an excellent opportunity also for the developing nations, promoting their economic growth by the conversion of biowaste into added value goods. However, such carbon may not reach the desired performance for SCs. In this work, we used laser processing technology for enhancing the capacitance of SC electrodes composed of activated carbon obtained from rice husk produced in Nigerian farmlands. The activated carbon powder was synthesized by conventional carbonization-chemical activation processes and treated with microwaves. Afterwards, the CO2 laser processing of thin film electrodes composed of a mixture of the carbon powder with carbon black (conductive additive), and precursors as urea (for doping of the activated carbon with nitrogen), or manganese nitrate (for the crystallization of pseudocapacitive Mn3O4 nanoparticles on the carbon surface) was carried out for obtaining enhanced positrodes and negatrodes. The resulting hybrid electrodes exhibited a 3-fold increase of the capacitance (up to 134 F/g @ 10 mV/s) as compared to the raw carbon in the [0, 0.8] V potential window. Asymmetric SC devices integrated by carbon (-)//carbon-Mn3O4 (+) laser-treated electrodes, operating at 1.2 V voltage, revealed up to 300 × higher energy and power densities than symmetric SCs composed of raw carbon electrodes.

Investigation of material ejection in laser decal transfer-based µ-3D printing of ZnO ceramics with microsecond pulsed CO2 laser

Investigation of material ejection in laser decal transfer-based µ-3D printing of ZnO ceramics with microsecond pulsed CO2 laser

Combined Stromal Vascular Fraction and Fractional CO2 Laser Therapy for Hypertrophic Scar Treatment: A Systematic Review and Meta-Analysis.

Hypertrophic scars (HTSs) result from aberrant wound healing processes, leading to raised, thickened tissue with functional discomfort and cosmetic concerns. Current treatments, including corticosteroid injections and laser therapy, have limitations. Stromal vascular fraction (SVF) therapy and CO2 laser treatment offer promising avenues, with SVF therapy showing regenerative potential and CO2 laser therapy promoting precise tissue removal and wound healing. This study aims to investigate the combined application of SVF therapy and CO2 laser treatment for HTS, aiming to enhance treatment efficacy, tissue remodeling, and aesthetic outcomes, ultimately improving patient satisfaction in HTS management. PubMed, Scopus, Embase, and Web of Science databases have been searched for relevant studies. The "R" software (version 4.3.1) along with the "tidyverse" and "meta" statistical packages utilized to analyze data related to the efficiency of this combined method. A random-effects model was fitted to the data. For each study, continuous outcomes were pooled by calculating the standardized mean difference, along with their 95% confidence intervals. The assessment of heterogeneity utilized the I2 and chi-squared tests, applying the random effect model. Six articles fulfilled our inclusion criteria and were included in our review. Results from the pooled analysis of Vancouver Scar Scale (VSS) scores across three included studies indicated a significant impact of the SVF+CO2 method on VSS scores post-treatment (SMD=-3.0144; 95% CI:-4.3706 to -1.6583, p<0.0001). However, analysis of transepidermal water loss levels before and after treatment showed no significant difference (SMD=-2.7603; 95% CI: -6.8729 to 1.3522; p=0.1883). Comparatively, in a pooled analysis of two studies, the combined SVF+CO2 method demonstrated superior efficacy in VSS scores compared to other methods (SMD= -1.3573; 95% CI: -2.2475 to -0.4672, p = 0.0028), with moderate heterogeneity across studies (I^2=23.0%, p = 0.2545). The combined application of SVF and CO2 laser treatment shows significant promise in improving hypertrophic scars' appearance and texture. The SVF+CO2 method demonstrates superior efficacy compared to other modalities, suggesting its potential as a valuable therapeutic approach for hypertrophic scar management. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

HPMC-Zein Film-forming Gel Loaded with 5-Fluorouracil Coupled with CO2 Laser Dermabrasion for Managing Stable Vitiligo.

Vitiligo is a significant dermatological challenge affecting 0.5 to 2% of the global population. Despite the various existing medical approaches, current vitiligo treatments are far from ideal. The present study aimed to prepare and evaluate a film-forming gel of 5 fluorouracil (5FU) using different ratios of hydroxypropyl methylcellulose (HPMC) and Zein for treating vitiligo. The prepared film-forming gels were fully characterized in terms of morphology, Fourier-transform infrared spectroscopy, drug content, pH, drying time, in-vitro drug release, and clinical investigation. A 32-full factorial design was used to study the impact of varying concentrations of HPMC (X1) and Zein (X2) on the percentage of 5FU released (Y1) from the prepared film-forming gels. Scanning electron microscopy (SEM) revealed a cross-linked network structure between polymers. An increase in HPMC concentration (2-4%) correlated with higher 5FU release, whereas increased Zein concentration (1-2%) resulted in reduced 5FU release. Furthermore, patients treated with 5FU film-forming gel after dermabrasion with fractional CO2 (FCO2) laser exhibited a significant decrease in JAK3 gene expression and higher effectiveness than those treated with FCO2 laser alone. Our results suggest that the film-forming gel of 5FU is promising as an effective formulation for treating vitiligo.

Comparative study of plasma, laser, and flame induced activation of HDPE liner surfaces of type 4 hydrogen vessels

ABSTRACT In our study, we compare the surface modifications of coarse HDPE surface induced by atmospheric air plasma, CO2 laser, and flame treatments. An order of WCA decrease of air plasma>flame>CO2 laser methods was detected. The improvement in adhesion strength measured 5 days after the activations followed the same trend. FT-IR and EDS proved that different oxygen compounds were formed after treatments, resulting in increased polar component of the total surface energy. Flame activation showed a saturation character regarding the O-moiety. Hydrophobic recovery showed a linear behavior, with a larger decreasing slope for the polar component than the total surface energy. Plasma treatments induced higher recovery rate; however, restore was not complete here either. The effects of the different CO2 irradiation intensities were nonlinear; SEM and roughness measurements revealed surface ablation or structure formation on the different samples, while after plasma and flame treatment a hilly microtexture appeared. With different mechanisms and intensities, all the tested methods are suitable for increasing the adhesion strength on HDPE surfaces.

Optimization of efficiency of short-pulsed fast flow CO2 laser amplifier with dual-band and multispectral lines.

In this paper, we optimize the amplification efficiency of a nanosecond pulse CO2 laser in a fast flow amplifier using dual-band and multispectral lines techniques. Utilizing a six-temperature model and a random rotational relaxation model, we simulate the time-domain amplification process of dual-band and multispectral lines short-pulse seeds in a fast flow CO2 laser amplifier, analyzing the effects of input pulse fluence, pulse width, and spectral line composition on amplification efficiency. Compared to single-line 10P(20) amplification, the extraction efficiency of 10.6-µm and 9.6-µm dual-band two-line 15-ns pulses is improved by approximately 70%, surpassing that of 10.6-µm single-band four-line amplification. This study is of great significance for the efficient amplification of short-pulse CO2 lasers and the generation of extreme ultraviolet light from laser produced plasma.

Carbon Dioxide Laser as Adjuvant Therapy for Human Papillomavirus-Related Squamous Intraepithelial Vulvar Lesions in Chronically Immunosuppressed Women: A Long-Term Real-Life Study

Carbon Dioxide Laser as Adjuvant Therapy for Human Papillomavirus-Related Squamous Intraepithelial Vulvar Lesions in Chronically Immunosuppressed Women: A Long-Term Real-Life Study