Ionization and dissociation of linear triatomic molecules, carbon dioxide, are studied in 50-fs 800-nm strong laser fields using time-of-flight mass spectrometer. The yields of double charged ions CO2^2＋ and various ...Ionization and dissociation of linear triatomic molecules, carbon dioxide, are studied in 50-fs 800-nm strong laser fields using time-of-flight mass spectrometer. The yields of double charged ions CO2^2＋ and various fragment ions（CO^＋,O^n＋, and C^n＋（n = 1, 2）） are measured as a function of ellipticity of laser polarization in the intensity range from 5.0 ×10^13W/cm2 to 6.0 × 10^14W/cm^2. The results demonstrate that non-sequential double ionization, which is induced by laser-driven electron recollision, dominates double ionization of CO2 in the strong IR laser field with intensity lower than2.0 × 10^14W/cm^2. The electron recollision could also have contribution in strong-field multiple ionization and formation of fragments of CO2 molecules. The present study indicates that the intensity and ellipticity dependence of ions yields can be used to probe the complex dynamics of strong-field ionization/dissociation of polyatomic molecules.展开更多
Since carbon dioxide laser is excellent for incision, hemostasis, coagulation, and vaporization of soft tissues, it has been widely applied in clinical treatments as the laser knife. In these days, flexible thin hollo...Since carbon dioxide laser is excellent for incision, hemostasis, coagulation, and vaporization of soft tissues, it has been widely applied in clinical treatments as the laser knife. In these days, flexible thin hollow optical fibers transmitting mid-infrared light have been developed, and the application of carbon dioxide laser to endoscopic therapy has become possible. However, it is expected that the irradiation effect is influenced by the change in the laser power at the tip of the hollow optical fiber due to the change in the transmittance by the bending loss. The purpose of this research is to quantitatively evaluate the change in the output power and therapeutic effect by bending the hollow optical fiber in a gastrointestinal endoscope. The change in the transmittance of the hollow optical fiber due to the insertion of the fiber into the endoscope and bending of the head of the endoscope was measured. Then, the relationship between the irradiated laser power and the incision depth for a porcine stomach was investigated. As the results, the most significant decrease in the transmittance of the hollow optical fiber was caused by the insertion of the fiber into the instrument channel of the endoscope, and bending of the head of the endoscope with the angle of 90° decreased the output laser power and incision depth by 10% and 25%, respectively. Therefore, it was confirmed that the bending loss of the hollow optical fiber due to the bending of the head of the endoscope had no significant influence on the endoscopic therapy using the carbon dioxide laser.展开更多
The direct excitation of CO2 using fast （nanosecond） and ultrafast （femtosecond） pulsed lasers was investigated.A gas reaction cell was used to excite CO2 in a 50：50 mixture of CO2 and CH4 using nano-and femtosec...The direct excitation of CO2 using fast （nanosecond） and ultrafast （femtosecond） pulsed lasers was investigated.A gas reaction cell was used to excite CO2 in a 50：50 mixture of CO2 and CH4 using nano-and femtosecond laser systems,to induce a reaction between these two compounds.FT-IR spectra showed that CO was formed using the nanosecond and femtosecond laser systems.It was also found that hydrocarbons,containing C-C bonds were formed.For both the nanosecond and femtosecond laser,it was found that more C-C higher hydrocarbons were formed after 5 h compared to 3 h of irradiation.Irradiation at pressures of 250,350 and 500 kPa with the femtosecond laser system showed the expected increase in the amount of CO formed with an increase in pressure.Results from this study showed that carbon dioxide and methane can be activated successfully using nanosecond laser pulses at 2000 nm and femtosecond laser pulses at 795 or 2000 nm and that these activated species react to form CO and C-C containing products.展开更多
The treatment of atrophoderma vermiculatum is challenging. A 7-year-old girl had a unilateral atrophic skin lesion on her right cheek, which was diagnosed as unilateral atrophoderma vermiculata. She was treated by car...The treatment of atrophoderma vermiculatum is challenging. A 7-year-old girl had a unilateral atrophic skin lesion on her right cheek, which was diagnosed as unilateral atrophoderma vermiculata. She was treated by carbon dioxide and 595 nm pulsed dye laser and carbon dioxide laser. This resulted in prevention of the lesional progression with favorable cosmetic appearance of the skin.展开更多
Background:Hypertrophic scars are one of the main complications that affect the quality of life of patients after burns.Many methods have been shown to be effective in the treatment of hypertrophic scars,such as ablat...Background:Hypertrophic scars are one of the main complications that affect the quality of life of patients after burns.Many methods have been shown to be effective in the treatment of hypertrophic scars,such as ablative fractional CO_(2) laser(AFCL)and platelet-rich plasma(PRP).However,there are few studies on the effect of the combined application of these measures.The purpose of this study was to explore the therapeutic effect of AFCL combined with PRP on hypertrophic burn scars.Methods:A retrospective clinical observation study was conducted on 50 patients with hypertrophic burn scars.The AFCL+PRP group included 31 patients who received AFCL combined with PRP treatment;the AFCL group included 19 patients who received AFCL treatment only.The University of North Carolina 4P Scar Scale(UNC4P)and the Vancouver Scar Scale(VSS)scores that were collected before each treatment were used as indicators of the effectiveness of the previous treatment.The scores recorded at the second,fourth and seventh months were analysed.Results:The demographic data of the 2 groups were not significantly different.Before treatment,therewas no difference in the UNC4P and VSS scores between the 2 groups.Therewas a significant decline in the UNC4P and VSS total scores over 6 months in both groups(p<0.05)and scores in the 2 groups were comparable after 3 and 6 months(p<0.05).UNC4P scores in the AFCL+PRP group decreased from a mean of 8.26 to 2.61(p<0.05)with a concomitant drop in VSS scores from a mean of 11.74 to 6.06(p<0.01).In the AFCL group UNC4P and VSS scores decreased from 7.68 to 4.63(p<0.05)and from 10.89 to 8.16(p<0.05),respectively.The sub-items of these 2 assessments were analysed and the results suggest that AFCL combined with PRP can comprehensively improve scarring.Conclusions:This study shows that PRP is an effective adjunct for AFCL in the treatment of hypertrophic burn scars and that the combination of PRP and AFCL proved to be more useful than AFCL alone.This combination may be a new and effective clinical practice for the treatment of scars.However,larger and higher-level clinical studies are still needed to determine its efficacy and possible mechanisms.展开更多
Introduction:Papular scarring of the nose and chin due to acne is an under-reported,under-recognized,and under-treated condition.Ablative carbon dioxide laser therapy(10,600 nm,continuous mode,energy of 15W)under loca...Introduction:Papular scarring of the nose and chin due to acne is an under-reported,under-recognized,and under-treated condition.Ablative carbon dioxide laser therapy(10,600 nm,continuous mode,energy of 15W)under local anesthesia is one of the choice.Here,we report series of patients with papular acne scars successfully treated with ablative carbon dioxide laser.Cases presentation:Five patients with papular scars of the nose and chin due to acne were treated at an outpatient dermatology clinic.All had type V skin according to the Fitzpatrick skin classification.Ablative carbon dioxide laser therapy(10,600 nm,continuous mode,energy of 15W)was performed under topical anesthesia.The patients were re-examined at 2-to 3-week intervals,and laser treatment was repeated as needed.Discussion:All of the five patients showed encouraging results.Good cosmetic results were achieved in all patients.The drawbacks of treatment were mild to moderate pain during the procedure and the need for posttreatment skin care.Conclusion:Ablative carbon dioxide laser therapy can potentially be used as a safe and effective treatment for papular scars of the nose and chin due to acne.展开更多
Background:Fractional CO_(2) laser plays an important role in scar management post split-thickness skin graft by loosening the graft contracture and restoring the smoothness of the surface.However,the optimal treatmen...Background:Fractional CO_(2) laser plays an important role in scar management post split-thickness skin graft by loosening the graft contracture and restoring the smoothness of the surface.However,the optimal treatment protocol remains unknown.This study applied a dual-scan protocol to achieve both releasing and ablation of contracted skin graft.We comprehensively describe this treatment method and compare the efficacy and safety between this dual-scan method and the conventional mono-scan mode.Methods:A hypercontracted scar model after split-thickness skin grafting in red Duroc pigs was established.All scars meeting the inclusion criteria were randomly divided into four groups:high fluence–low density(HF–LD),low fluence–high density(LF–HD),combined group and control group.The energy per unit areawas similar in the HF–LD and LF–HD groups.Two laser interventions were performed at a 6-week interval.The efficacy of the treatment was evaluated by objective measures of scar area,release rate,elasticity,thickness and flatness,while the safetywas evaluated based on adverse reactions and melanin index.Collagen structurewas observed histologically.The animals were followed up for a maximum of 126 days after modeling.Results:A total of 28 contracted scars were included,7 in each group.At 18 weeks postoperatively,the HF–LD and the combined groups showed significantly increased scar release rate(p=0.000)and elasticity(p=0.036)and decreased type I/III collagen ratio(p=0.002)compared with the control and LF–HD groups.In terms of flatness,the combined group was significantly better than the HF–LD group for elevations<1mm(p=0.019).No significant skin side effects,pigmentation or scar thickness changes were observed at 18 weeks.Conclusions:Dual-scan protocol could achieve superficial ablation and deep release of contracted split-thickness skin graft in a single treatment,with similar contraction release and texture improvement compared to a single deep scan.Its main advantage is to restore a smoother scar appearance.Adequate laser penetration was necessary for the release of contracted scars.展开更多
Purpose Carbon dioxide(CO_(2))lasers enable precise vaporization of lesions with minimal bleeding and have been widely used to excise a wide variety of lesions with good results.Papillomatosis is a disorder characteri...Purpose Carbon dioxide(CO_(2))lasers enable precise vaporization of lesions with minimal bleeding and have been widely used to excise a wide variety of lesions with good results.Papillomatosis is a disorder characterized by a wart-like growth that tends to recur relentlessly after surgical removal or medical treatment.Treatment of pediatric facial papillomatosis by utilizing a CO_(2)laser is a viable alternative strategy.This paper presents a case of an 8-month-old child with facial papilloma,that we treated by ablation using a CO_(2)laser,and discusses the efficacy of this treatment modality.Methods A case of pediatric facial papilloma treated with CO_(2)laser ablation was reported,and the benefits of this treatment modality were reviewed and analyzed in the context of the existing literature.Results Under general anesthesia,the lesional tissue of the left lip was excised,and the pathological diagnosis was confirmed to be maxillofacial papilloma.The lesions were surgically ablated in stages using a CO_(2)laser,and erythromycin ointment was applied to the treated areas after surgery.A total of three rounds of CO_(2)laser treatment were performed.The child had no complications during or after the operations;the child’s facial appearance was significantly improved,and there was no sign of recurrence during the 6-month follow-up.Conclusions The CO_(2)laser was useful for resection of this patient who had pediatric facial papillomatosis,and it can restore an aesthetic facial soft tissue profile without significant residual facial deformity.The CO_(2)laser can achieve precise vaporization resection of diseased tissue with minimal blood loss and a good cosmetic result.展开更多
基金supported by the National Basic Research Program of China(Grant No.2013CB922200)the National Natural Science Foundation of China(Grant Nos.11034003 and 11274140)
文摘Ionization and dissociation of linear triatomic molecules, carbon dioxide, are studied in 50-fs 800-nm strong laser fields using time-of-flight mass spectrometer. The yields of double charged ions CO2^2＋ and various fragment ions（CO^＋,O^n＋, and C^n＋（n = 1, 2）） are measured as a function of ellipticity of laser polarization in the intensity range from 5.0 ×10^13W/cm2 to 6.0 × 10^14W/cm^2. The results demonstrate that non-sequential double ionization, which is induced by laser-driven electron recollision, dominates double ionization of CO2 in the strong IR laser field with intensity lower than2.0 × 10^14W/cm^2. The electron recollision could also have contribution in strong-field multiple ionization and formation of fragments of CO2 molecules. The present study indicates that the intensity and ellipticity dependence of ions yields can be used to probe the complex dynamics of strong-field ionization/dissociation of polyatomic molecules.
文摘Since carbon dioxide laser is excellent for incision, hemostasis, coagulation, and vaporization of soft tissues, it has been widely applied in clinical treatments as the laser knife. In these days, flexible thin hollow optical fibers transmitting mid-infrared light have been developed, and the application of carbon dioxide laser to endoscopic therapy has become possible. However, it is expected that the irradiation effect is influenced by the change in the laser power at the tip of the hollow optical fiber due to the change in the transmittance by the bending loss. The purpose of this research is to quantitatively evaluate the change in the output power and therapeutic effect by bending the hollow optical fiber in a gastrointestinal endoscope. The change in the transmittance of the hollow optical fiber due to the insertion of the fiber into the endoscope and bending of the head of the endoscope was measured. Then, the relationship between the irradiated laser power and the incision depth for a porcine stomach was investigated. As the results, the most significant decrease in the transmittance of the hollow optical fiber was caused by the insertion of the fiber into the instrument channel of the endoscope, and bending of the head of the endoscope with the angle of 90° decreased the output laser power and incision depth by 10% and 25%, respectively. Therefore, it was confirmed that the bending loss of the hollow optical fiber due to the bending of the head of the endoscope had no significant influence on the endoscopic therapy using the carbon dioxide laser.
文摘The direct excitation of CO2 using fast （nanosecond） and ultrafast （femtosecond） pulsed lasers was investigated.A gas reaction cell was used to excite CO2 in a 50：50 mixture of CO2 and CH4 using nano-and femtosecond laser systems,to induce a reaction between these two compounds.FT-IR spectra showed that CO was formed using the nanosecond and femtosecond laser systems.It was also found that hydrocarbons,containing C-C bonds were formed.For both the nanosecond and femtosecond laser,it was found that more C-C higher hydrocarbons were formed after 5 h compared to 3 h of irradiation.Irradiation at pressures of 250,350 and 500 kPa with the femtosecond laser system showed the expected increase in the amount of CO formed with an increase in pressure.Results from this study showed that carbon dioxide and methane can be activated successfully using nanosecond laser pulses at 2000 nm and femtosecond laser pulses at 795 or 2000 nm and that these activated species react to form CO and C-C containing products.
文摘The treatment of atrophoderma vermiculatum is challenging. A 7-year-old girl had a unilateral atrophic skin lesion on her right cheek, which was diagnosed as unilateral atrophoderma vermiculata. She was treated by carbon dioxide and 595 nm pulsed dye laser and carbon dioxide laser. This resulted in prevention of the lesional progression with favorable cosmetic appearance of the skin.
基金supported by the National Nature Science Foundation of China(81701899)the Youth Incubation Plan of the Military Medical Science and Technology(16QNP091)+1 种基金the CAMS Innovation Fund for Medical Sciences(2019-I2M-5-076)the high level achievement cultivation plan of the Naval Medical University(2018-CGPZ-B03).
文摘Background:Hypertrophic scars are one of the main complications that affect the quality of life of patients after burns.Many methods have been shown to be effective in the treatment of hypertrophic scars,such as ablative fractional CO_(2) laser(AFCL)and platelet-rich plasma(PRP).However,there are few studies on the effect of the combined application of these measures.The purpose of this study was to explore the therapeutic effect of AFCL combined with PRP on hypertrophic burn scars.Methods:A retrospective clinical observation study was conducted on 50 patients with hypertrophic burn scars.The AFCL+PRP group included 31 patients who received AFCL combined with PRP treatment;the AFCL group included 19 patients who received AFCL treatment only.The University of North Carolina 4P Scar Scale(UNC4P)and the Vancouver Scar Scale(VSS)scores that were collected before each treatment were used as indicators of the effectiveness of the previous treatment.The scores recorded at the second,fourth and seventh months were analysed.Results:The demographic data of the 2 groups were not significantly different.Before treatment,therewas no difference in the UNC4P and VSS scores between the 2 groups.Therewas a significant decline in the UNC4P and VSS total scores over 6 months in both groups(p<0.05)and scores in the 2 groups were comparable after 3 and 6 months(p<0.05).UNC4P scores in the AFCL+PRP group decreased from a mean of 8.26 to 2.61(p<0.05)with a concomitant drop in VSS scores from a mean of 11.74 to 6.06(p<0.01).In the AFCL group UNC4P and VSS scores decreased from 7.68 to 4.63(p<0.05)and from 10.89 to 8.16(p<0.05),respectively.The sub-items of these 2 assessments were analysed and the results suggest that AFCL combined with PRP can comprehensively improve scarring.Conclusions:This study shows that PRP is an effective adjunct for AFCL in the treatment of hypertrophic burn scars and that the combination of PRP and AFCL proved to be more useful than AFCL alone.This combination may be a new and effective clinical practice for the treatment of scars.However,larger and higher-level clinical studies are still needed to determine its efficacy and possible mechanisms.
文摘Introduction:Papular scarring of the nose and chin due to acne is an under-reported,under-recognized,and under-treated condition.Ablative carbon dioxide laser therapy(10,600 nm,continuous mode,energy of 15W)under local anesthesia is one of the choice.Here,we report series of patients with papular acne scars successfully treated with ablative carbon dioxide laser.Cases presentation:Five patients with papular scars of the nose and chin due to acne were treated at an outpatient dermatology clinic.All had type V skin according to the Fitzpatrick skin classification.Ablative carbon dioxide laser therapy(10,600 nm,continuous mode,energy of 15W)was performed under topical anesthesia.The patients were re-examined at 2-to 3-week intervals,and laser treatment was repeated as needed.Discussion:All of the five patients showed encouraging results.Good cosmetic results were achieved in all patients.The drawbacks of treatment were mild to moderate pain during the procedure and the need for posttreatment skin care.Conclusion:Ablative carbon dioxide laser therapy can potentially be used as a safe and effective treatment for papular scars of the nose and chin due to acne.
基金supported by Shanghai Municipal Education Commission Gaofeng Clinical Medicine Grant Support(20152227)The national natural science foundation of China(81772098)Scientific research foundation of Shanghai Municipal Commission of Health and Family Planning(20154Y0023).
文摘Background:Fractional CO_(2) laser plays an important role in scar management post split-thickness skin graft by loosening the graft contracture and restoring the smoothness of the surface.However,the optimal treatment protocol remains unknown.This study applied a dual-scan protocol to achieve both releasing and ablation of contracted skin graft.We comprehensively describe this treatment method and compare the efficacy and safety between this dual-scan method and the conventional mono-scan mode.Methods:A hypercontracted scar model after split-thickness skin grafting in red Duroc pigs was established.All scars meeting the inclusion criteria were randomly divided into four groups:high fluence–low density(HF–LD),low fluence–high density(LF–HD),combined group and control group.The energy per unit areawas similar in the HF–LD and LF–HD groups.Two laser interventions were performed at a 6-week interval.The efficacy of the treatment was evaluated by objective measures of scar area,release rate,elasticity,thickness and flatness,while the safetywas evaluated based on adverse reactions and melanin index.Collagen structurewas observed histologically.The animals were followed up for a maximum of 126 days after modeling.Results:A total of 28 contracted scars were included,7 in each group.At 18 weeks postoperatively,the HF–LD and the combined groups showed significantly increased scar release rate(p=0.000)and elasticity(p=0.036)and decreased type I/III collagen ratio(p=0.002)compared with the control and LF–HD groups.In terms of flatness,the combined group was significantly better than the HF–LD group for elevations<1mm(p=0.019).No significant skin side effects,pigmentation or scar thickness changes were observed at 18 weeks.Conclusions:Dual-scan protocol could achieve superficial ablation and deep release of contracted split-thickness skin graft in a single treatment,with similar contraction release and texture improvement compared to a single deep scan.Its main advantage is to restore a smoother scar appearance.Adequate laser penetration was necessary for the release of contracted scars.
基金supported by grants from the Guangzhou Science and Technology Project(#202103000093)The Key Laboratory of Malignant Tumour Gene Regulation and Target Therapy of Guangdong Higher Education Institutes,Sun Yat-sen University(Grant KLB09001)the Key Laboratory of Malignant Tumour Molecular Mechanism and Translational Medicine of Guangzhou Bureau of Science and Information Technology([2013]163).
文摘Purpose Carbon dioxide(CO_(2))lasers enable precise vaporization of lesions with minimal bleeding and have been widely used to excise a wide variety of lesions with good results.Papillomatosis is a disorder characterized by a wart-like growth that tends to recur relentlessly after surgical removal or medical treatment.Treatment of pediatric facial papillomatosis by utilizing a CO_(2)laser is a viable alternative strategy.This paper presents a case of an 8-month-old child with facial papilloma,that we treated by ablation using a CO_(2)laser,and discusses the efficacy of this treatment modality.Methods A case of pediatric facial papilloma treated with CO_(2)laser ablation was reported,and the benefits of this treatment modality were reviewed and analyzed in the context of the existing literature.Results Under general anesthesia,the lesional tissue of the left lip was excised,and the pathological diagnosis was confirmed to be maxillofacial papilloma.The lesions were surgically ablated in stages using a CO_(2)laser,and erythromycin ointment was applied to the treated areas after surgery.A total of three rounds of CO_(2)laser treatment were performed.The child had no complications during or after the operations;the child’s facial appearance was significantly improved,and there was no sign of recurrence during the 6-month follow-up.Conclusions The CO_(2)laser was useful for resection of this patient who had pediatric facial papillomatosis,and it can restore an aesthetic facial soft tissue profile without significant residual facial deformity.The CO_(2)laser can achieve precise vaporization resection of diseased tissue with minimal blood loss and a good cosmetic result.
