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<scp> CO <sub/>2</sub></scp> laser treatment for plantar warts in children: A case series
摘要： Several types of human papillomaviruses (HPV) induce warts. Warts are one of the most common infections in childhood with a reported prevalence of up to 20%. Warts are divided clinically into genital and non-genital forms. Plantar warts are common non-genital warts. In this series five pediatric cases treated with C02 laser for their plantar warts are presented. One patient was a known case of Hodgkin`s lymphoma. Three of our patients had history of unsuccessful treatments with other modalities while the other had received no previous treatment. CO2 laser with continuous mode (focused and defocused) was used. In our cases, only one session was enough for clearance of the warts. All the patients were visited 1 week and 3 months after treatment to assess the efficacy and any possible recurrences. Follow-up showed that all the patients remained in remission up to 3-months post-treatment with no adverse events.
关键词： human papillomavirus,CO2 laser therapy,plantar wart
更新于2025-09-23 15:19:57
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Effectiveness of CO <sub/>2</sub> laser on urogenital syndrome in women with a previous gynecological neoplasia: a multicentric study
摘要： background Many women diagnosed with gynecological cancers undergo adjuvant therapy, which may lead to transient or permanent menopause that ultimately leads to urogenital syndrome and vulvovaginal atrophy. Studies advise against the use of estrogen in women with a history of hormone- dependent cancer. One alternative is vaginal microablative fractional CO2 laser, which promotes tissue regeneration through the production of collagen and elastic fibers. Objective To evaluate the effectiveness of CO2 laser in the treatment of urogenital syndrome—in particular, symptomatic vulvovaginal atrophy in women who have survived gynecological cancers. Methods A retrospective study was carried out, including all patients with a history of gynecological cancers and vulvovaginal atrophy who underwent CO2 laser treatment between November 2012 and February 2018 in four Italian centers. The study was approved by the local ethics committee of each participating institution. The inclusion criteria were women aged between 18 and 75; Eastern Cooperative Oncology Group performance status <2; and history of breast, ovarian, cervical, or uterus cancer. Patients had to have vulvovaginal atrophy and at least one of the following symptoms of urogenital syndrome: vaginal dryness, dyspareunia, vaginal introitus pain, burning, or itching. Three applications were administered at baseline, 30 days, and 60 days. All patients were evaluated before the first laser session, at each session, and 4 weeks after the last session. In particular, patients were asked to indicate the intensity of symptoms before the first session and 4 weeks after the last session, using Visual Analog Scale (VAS) scoring from 0 ('no discomfort') to 10 ('maximum discomfort'). results A total of 1213 patients underwent CO2 treatment and of these, 1048 were excluded because they did not meet the inclusion criteria in the analysis. Finally, a total of 165 patients were included in the study. The mean age at the time of treatment was 53 years (range 31–73). Dryness improved by 66%, dyspareunia improved by 59%, burning improved by 66%, pain at introitus improved by 54%, and itching improved by 54%. The side effects were evaluated as pain greater than VAS score 6 during and after the treatment period. No side effects were seen in any sessions. Conclusions Fractional microablative CO2 offers an effective strategy in the management of the symptoms of genitourinary syndrome in post- menopausal women and in survivors of gynecological cancer.
关键词： vulvovaginal atrophy,menopausal symptoms,CO2 laser,urogenital syndrome,gynecological cancer
更新于2025-09-23 15:19:57
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Laser cutting optimization model with constraints: Maximization of material removal rate in CO <sub/>2</sub> laser cutting of mild steel
摘要： Taking full advantage of what laser cutting technology offers in terms of achieving superb quality cuts at low cost and high production rates requires the optimization of laser cutting parameters. This implies the need to formulate and solve different laser cutting optimization problems. In this article, an optimization model for CO2 laser cutting of mild steel is developed. The laser cutting optimization problem was explicitly formulated as a single-objective optimization problem with five non-linear constraints of the equality, inequality and range type. The goal was to determine the laser cutting parameter values so as to maximize the material removal rate while simultaneously considering practical process constraints related to dross formation, kerf width, perpendicularity deviation, surface roughness and severance energy. Two crossed experimental designs of different resolutions were performed in order to define six mathematical models, which were used in the formulation of the optimization problem. For the purpose of optimization, the exhaustive iterative search algorithm was applied, since it determines solutions whose optimality is guaranteed in the given discrete space of input variable values. The practical usability of the developed laser cutting optimization model and the effectiveness of the applied optimization approach were proved while solving a real case study aimed at the optimization of laser cutting parameters for cutting parts for the furnace industry.
关键词： mild steel,CO2 laser cutting,optimization model,material removal rate,non-linear constraints
更新于2025-09-23 15:19:57
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Effectiveness of a combination therapy of traditional Chinese medicine and CO <sub/>2</sub> laser treatment for condyloma acuminatum
摘要： Background: Condyloma acuminatum (CA) is both highly infectious and frequently recurring and requires long-term, repeated treatments, which seriously impact the physical and psychological health of patients. The purpose of the present study was to investigate the effectiveness of a combination therapy of traditional Chinese medicine and CO2 laser on CA and the relationship between CA relapse and cellular immunity. Methods: The study cohort consisted of 160 CA patients who underwent ambulatory treatment between January 2017 and January 2019 in the Department of Dermatology and Venerology of our hospital. The 160 patients were randomly divided into two groups: a combination therapy group (80 cases), who underwent CO2-laser treatment followed by three courses of oral traditional Chinese medicine and a control group (80 cases), who were only treated with the CO2 laser to remove warts. The efficacy of the CO2-laser treatment was evaluated on the first month after treatment and relapse was evaluated at monthly follow-ups for 6 months. Additionally, 20 normal volunteers were also recruited. Three months before and after treatment, the cellular immunity factors of peripheral blood T lymphocyte subsets, including CD4+, CD8+, CD4+/CD8+ and IL-2, were detected and compared between CA patients and normal volunteers, the combination therapy and control groups, and the relapse and cure groups to determine whether there were statistical differences. Results: Compared with normal volunteers, CA patients exhibited lower CD4+, CD4+/CD8+, and IL-2 levels and higher CD8+ levels (P < 0.05). In addition, the rates of relapse for the combination therapy and control groups were 25.7 and 40.8%, respectively. However, the comprehensive immunity factors showed no statistical difference (P > 0.05) before treatment. Three months after treatment, factors including CD4+ and CD4+/CD8+ were higher in the combination therapy group than in the control group (P < 0.05), and CD8+ and IL-2 showed no statistical difference (P > 0.05); factors including CD4+, CD4+/CD8+, and IL-2 were higher and CD8+ was lower in the cure group than in the relapse group (P < 0.05). Conclusion: The therapy combination of traditional Chinese medicine and CO2-laser treatment can reduce the relapse rate of CA. It might be traditional Chinese medicine combined with CO2-laser treatment regulate liver meridian, Qi and blood, restore the balance between various subgroups.
关键词： cellular immunity,traditional Chinese medicine,condyloma acuminatum,CO2 laser
更新于2025-09-23 15:19:57
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Slab RF-discharge carbon dioxide laser with active mode-locking
摘要： Mode-locking with an acousto-optic modulator was for the first time demonstrated for a repetitively pulsed (150 Hz) slab RF discharge CO2 laser. The mode-locked CO2 laser emitted trains of 5.5 ns pulses following with 27.25 MHz repetition rate. Mode-locking also affected the laser pulses envelope in respect to free-runing mode. The numerical estimation of the laser system scalability indicated an opportunity to develop a very compact CO2 laser emitting sub-nanosecond pulses.
关键词： slab design,mode-locking,RF discharge,CO2 laser,nanosecond pulse
更新于2025-09-23 15:19:57
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Investigation of hole quality in drilled Ti/CFRP/Ti laminates using CO2 laser
摘要： The machinability of titanium (Ti) and carbon fiber reinforced plastic (CFRP) (Ti/CFRP/Ti) laminates using CO2 laser is presented in this work. The effect of line energy and laser frequency on output responses such as heat affected zone (HAZ), taper angle (TA), metal composite interface (MCI) damage, surface roughness, dross height, and circularity were investigated. Line energy - the most influential parameter - demonstrated a threshold behavior; no drilling was observed below a certain line energy. Scanning acoustic microscopy (SAM), scanning electron microscopy (SEM), micro-computed tomography (μ-CT), and other imaging techniques were used to establish a correlation between laser parameters and CO2 laser machined damage in Ti/CFRP/Ti laminates. The results show that using a higher frequency and lower line energy can significantly improve the hole quality. However, dross free holes with minimum taper can be obtained using higher line energy.
关键词： Surface roughness,Circularity,Micro-hardness,CO2 laser,Dross height,HAZ,Drilling,Ti/CFRP/Ti,MCI damage factor,TA
更新于2025-09-23 15:19:57
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Fractional carbon dioxide laser combined with intradermal injection of autologous plateleta??rich plasma versus noncrossa??linked hyaluronic acid in the treatment of atrophic postacne scars: A split face study
摘要： Background: Atrophic acne scarring is a common cosmetic problem that may affect 95% of patients with acne. Aims: The objective is to evaluate the efficacy of the fractional CO2 laser combined with intradermal injection of PRP versus intradermal injection of noncross-linked hyaluronic acid in the treatment of different types of atrophic postacne scars. Methods: The study included 30 patients with postacne scars. All the patients received 3 treatments of fractional CO2 laser combined with intradermal injection of PRP at one side of the face compared with intradermal injection of noncross-linked hyaluronic acid at the other side of the face. Efficacy of the treatment was assessed by the physician's clinical assessment using Goodman and Baron's qualitative and quantitative grading systems and histopathological evaluation from six participants. Results: The study included 30 patients ages ranging from 25 to 44 years old. There was a statistically significant reduction in the severity of acne scars on both sides after treatment using qualitative and quantitative Goodman and Baron. Histopathological evaluation showed an increase in the collagen and elastic fiber content in both modalities with a more favorable outcome in the PRP-treated side. Conclusion: Both treatment modalities resulted in a significant clinical and histopathological improvement in atrophic postacne scar with insignificant difference between them.
关键词： HA,postacne scar,fractional CO2 laser,PRP
更新于2025-09-23 15:19:57
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[IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou, China (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - Design of Helical Tube Fiber Optic Fabry-Perot Cavity Pressure Sensor
摘要： An optical fiber helical tube pressure sensor based on Fabry-Perot cavity which is fabricated by CO2 laser thermal bonding technique is developed. The measuring range is 0~72MPa, the repeatability is 0.02% F·S and the hysteresis is 0.02% F·S.
关键词： helical tube,pressure,Fabry-Perot cavity,CO2 laser,sensor
更新于2025-09-19 17:15:36
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Improved conductivity of carbonized polyimide by CO <sub/>2</sub> laser graphitization
摘要： Direct laser writing (DLW) is a fast and cost-effective technique for printing conductive structures on flexible substrates such as polyimide (PI) by the conversion of insulative PI to conductive carbon. However, the conductivity (B103 S m?1) obtained by this method needs to be improved to compete with ink-jet printing of carbon-based materials. The reason behind the low conductivity achieved by the DLW process is due to the crystallinity and hybridization of bonding in carbonaceous structures. In this work, the DLW process has been implemented in two steps: the first step called carbonization was performed by writing pulsed CO2 laser on PI to form tracks which consist of amorphous tetrahedral carbon (a mixture of sp2 and sp3 hybridized carbon) having intrinsically low conductivity. The second step called graphitization is overwriting of the laser on the pre-carbonized tracks to convert sp3 hybridized bonds to sp2 hybridized bonds by the process called laser graphitization. The conductivity of tracks carbonized at (0.21 ± 0.02) W and fluence (3.31 ± 0.32) × 103 mJ cm?2 at a repetition rate of 0.1 kHz was 56.1 ± 3.1 S m?1 which increased to 146.7 ± 5.1 S m?1 upon overwriting with the laser at (0.50 ± 0.03) W and fluence (7.88 ± 0.47) × 103 mJ cm?2 at the same repetition rate. The photothermal process of carbonization and graphitization is modeled for the DLW process and the threshold power of both the processes is calculated and validated by Raman spectroscopy. Improved conductivity achieved by detailed understanding of the laser and material parameters involved in this transformation enables process optimization leading to future applications in scalable manufacturing of flexible bio-sensors and electrochemical energy storage devices.
关键词： Direct laser writing,carbonization,graphitization,CO2 laser,polyimide,conductivity
更新于2025-09-19 17:13:59
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Microhole Formation Behavior of Polypropylene Film Using CO<sub>2 </sub>Laser Irradiation
摘要： Biaxially oriented polypropylene films produced by simultaneous equi-biaxial stretching to the draw ratio of 4 (cid:186) 4 were perforated by the carbon dioxide laser under various laser fluences up to 426.3 J/cm2. After applying various laser fluences, the irradiated area was observed using a laser scanning confocal microscope. With the increase of fluence, the surface deformation with the formation of a crater surrounded by a doughnut-like rim was firstly observed at the laser fluence of 49.7 J/cm2, followed by the starting of the formation of a microhole surrounded by the rim at 113.7 J/cm2. The diameter of the microhole and the size of the rim increased rapidly with the increase of laser fluence. Mechanisms for the formation of a crater, the opening of a microhole, and the formation of surrounding rim were considered to be related to the surface tension and the shrinkage caused by molecular orientation relaxation. On the other hand, volume loss from the laser irradiated area was negligibly small at the moment of microhole opening, and started to increase rapidly when the fluence reached around 150 J/cm2. The microhole formation behavior was also observed by a high-speed camera. The velocity of microhole opening increased rapidly at first, presumably during the laser irradiation, and then slowed down after the cessation of laser irradiation. Theoretically estimated temperature distribution along the film thickness was compared with the laser perforation behavior. Starting of the deformation of film matched well with the starting of melting of the film surface. Film temperature was lower than the thermal decomposition temperature at the moment of the opening of a microhole, whereas at the moment of the starting of volume loss, film temperature was lower than the decomposition temperature estimated based on the heating rate of laser irradiated area, indicating that the decomposition and vaporization continues for a while after the cessation of laser irradiation.
关键词： microhole formation,molecular orientation relaxation,Polypropylene,laser fluence,CO2 laser,surface tension
更新于2025-09-19 17:13:59