In gemmology,the term“Alexandrite effect”is used to describe colour change phenomenon when a gemstone is observed under different light sources,usually between daylight and incandescent light.The definition of the A...In gemmology,the term“Alexandrite effect”is used to describe colour change phenomenon when a gemstone is observed under different light sources,usually between daylight and incandescent light.The definition of the Alexandrite effect is constantly being broadened with new discovery of gem resource.The traditional definition of the Alexandrite effect attributing the colour change phenomenon to the presence of two maximum transmission regions and a maximum absorption region in the absorption spectra.In this study,7 blue spinels and 5 blue gemstones(including tanzanite,kyanite,fluorite,and 2 sapphires)showing the Alexandrite effect were investigated.The goal is to explain the cause of blue-to-violet Alexandrite effect and the spectral features causing such colour change.In the UV-Vis spectra,all samples showed a maximum absorption peak in the range of 534-610 nm,within the green region to orange region.The traditional explanation of green to red Alexandrite effect required a transmission window in the red region;however,some of our samples did not show this transmission window and the blue-to-violet Alexandrite effect was still visible.Therefore,it is incomplete to explain the mechanism of the Alexandrite effect according to their characteristic absorption spectra,a systematic study based on modern colour science and colour perception in human vision is required to elucidate the blue-to-violet Alexandrite effect.展开更多
BACKGROUND We have previously proved that treatment of thick/deep infantile hemangiomas (IHs) with a long-pulse Alexandrite laser was clinically effective and safe. This article aims to investigate the efficiency of l...BACKGROUND We have previously proved that treatment of thick/deep infantile hemangiomas (IHs) with a long-pulse Alexandrite laser was clinically effective and safe. This article aims to investigate the efficiency of long-pulse Alexandrite laser use in treating thick and high-risk IHs located in particular anatomic areas and provides some new data on this issue. CASE SUMMARY A two-month-old girl with a thick and high-risk IH covering most of the right labia majora was examined in this study. The infant received four treatment sessions at 4- to 6-wk intervals with a long-pulse Alexandrite laser with settings as follows: 3 ms pulse duration, 8 mm spot size, 45 to 50 J/cm2 fluences, and dynamic cooling device (DCD) spray duration of 90 ms with a delay of 80 ms. Following each of the four treatment sessions, the IH showed a remarkable reduction in thickness and size without any sign of relapse. Ten months after the last treatment, the IH had completely regressed without adverse effects. During the laser treatment, no severe side effects were observed;blistering occurred only immediately after treatment and then scabbed over the next day, gradually improving in the following days. CONCLUSION Long-pulse Alexandrite laser treatment may be considered one of the first-line noninvasive therapeutic options for the treatment of thick IH.展开更多
Background and Objective: Unwanted hair growth is a discomforting issue affecting both genders. People have tried various methods to get rid of this situation. This study aims to evaluate the efficacy and safety of a ...Background and Objective: Unwanted hair growth is a discomforting issue affecting both genders. People have tried various methods to get rid of this situation. This study aims to evaluate the efficacy and safety of a combined Alexandrite and Nd:YAG laser treatment for permanent hair removal, drawing insights from existing literature. Materials and Methods:This study included a total of 2127 patients (302 males, 1825 females) aged 18 - 65, with complete data, who underwent hair removal treatment between December 2018 and April 2021. These patients were treated using the Duetta laser system (Quanta system, Samarate, Italy), combining Alexandrite 755 nm and Nd:YAG 1064 nm wavelengths. The patients’ skin types were classified according to the Fitzpatrick classification scale. Target area/areas for laser hair removal was/were determined. Laser parameters, pulse counts, pain levels assessed through the Visual Pain Scale (VPS), and patient satisfaction were documented based on skin types. Findings: Across various skin types, Types I - II exhibited the highest treatment success rates (87%), with the axillary region achieving the highest rate (83%) and the face region achieving the lowest rate (75%). Pain scale analysis indicated that 98% of patients tolerated the procedure well. Patient satisfaction levels exceeded 90%. Evaluation of complication rates revealed minimal occurrences. Conclusion: The combined Alexandrite and Nd:YAG laser system demonstrates both efficacy and safety across diverse skin types, attributed to its notable success rates, minimal adverse effects, and high patient tolerance.展开更多
Results of photoluminescence measurements for natural and synthetic alexandrite (BeAl2O4:Cr3+) are presented, where the samples are excited by the 488 nm line of an Ar+ laser, at different temperatures. The main issue...Results of photoluminescence measurements for natural and synthetic alexandrite (BeAl2O4:Cr3+) are presented, where the samples are excited by the 488 nm line of an Ar+ laser, at different temperatures. The main issue is the analysis of the Cr3+ transition in the chrysoberyl matrix (BeAl2O4), with major technological application as active media for laser action. Results indicate anomalous behavior of Cr33+ transition depending on the measurement temperature. A simple model to explain the phenomena is suggested.展开更多
The investigation of electrical properties in alexandrite (BeAl<sub>2</sub>O<sub>4</sub>:Cr<sup>3+</sup>) in synthetic and natural forms is presented in this paper. Alexandrite is a...The investigation of electrical properties in alexandrite (BeAl<sub>2</sub>O<sub>4</sub>:Cr<sup>3+</sup>) in synthetic and natural forms is presented in this paper. Alexandrite is a rare and precious mineral that changes color according to the light incident on it. In the synthetic form, it is used technologically as an active laser medium. The electrical characterization was obtained using the Thermally Stimulated Depolarization Current (TSDC) technique, an interesting tool to study the behavior of impurities in insulators. Alexandrite presented the electric dipole relaxation phenomenon, both in natural and in synthetic samples. It was possible to observe TSDC bands for the synthetic sample at around 170 K, and at around 175 K for the natural sample. Besides, photo-induced TSDC measurements were performed through the excitement of the samples by using a continuous wave argon laser. In addition, photoluminescence measurements were performed to verify in advance whether the laser light would be absorbed by the sample, and in order to complement the photo-induced TSDC measurements analysis. The results of photo-induced TSDC experiments have contributed to the understanding of the TSDC bands behavior: the results obtained with the technique suggest that there is an effective participation of Cr<sup>3+</sup> ions in the formation of TSDC bands because they were more intense when the sample was exposed to the argon laser beam.展开更多
Peutz-Jeghers syndrome(PJS)is a polygenic autosomal dominant disease characterized by multiple gastrointestinal polyps and pigmentation of the mucosa and skin.While there are a few reports regarding successful treatme...Peutz-Jeghers syndrome(PJS)is a polygenic autosomal dominant disease characterized by multiple gastrointestinal polyps and pigmentation of the mucosa and skin.While there are a few reports regarding successful treatment of intestinal polyps in PJS,there is little research regarding treatment of mucocutaneous melanosis.This study investigated the many advantages of using a Q-switched alexandrite laser to treat mucocutaneous melanosis.In this case,a 19-year-old male with PJS presented with labial lentigines and received two Q-switched alexandrite laser treatments in 2018.Subsequently,the efficacy of the treatment was evaluated.The result of the evaluation was that,after the two laser treatments,the labial lentigines were successfully removed,and there were no complications.展开更多
In order to determine the appropriate treatment interval, 267 patients who underwent 3 sessions of treatment with Q-switched alexandrite laser were divided into 4 groups according to treatment interval, and their clin...In order to determine the appropriate treatment interval, 267 patients who underwent 3 sessions of treatment with Q-switched alexandrite laser were divided into 4 groups according to treatment interval, and their clinical responses were compared. Among them, 187 were asked about the process of pigment fading. Moreover, light and transmission electron microscopy were performed. It was noted that the clinical response of the 5 - 6 month interval group was significantly better than that of the 3 - 4 month group, but showed no significant difference from that of the 7 - 8 or ≥ 9 month group. 80.21% of investigated patients stated that marked pigment fading could no longer be observed 7 months after irradiation. 4 months after irradiation, the degenerated melanosomes and cell debris were still scattered among collagen fibers, scavenged gradually by macrophage. In conclusion, an appropriate treatment interval is 5 - 6 months.展开更多
Ⅰ. INTRODUCTIONAlexandrite is a hopeful laser crystal not only because the sharp R-line shows laser action, as in ruby, but also the vibronic sideband is involved in the lasing of this crystal, in this case the syste...Ⅰ. INTRODUCTIONAlexandrite is a hopeful laser crystal not only because the sharp R-line shows laser action, as in ruby, but also the vibronic sideband is involved in the lasing of this crystal, in this case the system is of four-levels and is widely tunable （700 nm--800 nm）. We have studied the dynamic properties of the excited states of Cr<sup>3+</sup> in BeAl<sub>2</sub>O<sub>4</sub>. The relaxation of the system within the excited states reveals the dynamics of the interactions of the ion defects with phonons. As the time of relaxation展开更多
Objective:Q-switched lasers,including 1064-nm Nd:YAG nansecond laser (QSNYL),755-nm alexandrite nanosecond laser (QSAL),and 694-nm nanosecond ruby laser (QSRL),are clinically available for the treatment of acquired bi...Objective:Q-switched lasers,including 1064-nm Nd:YAG nansecond laser (QSNYL),755-nm alexandrite nanosecond laser (QSAL),and 694-nm nanosecond ruby laser (QSRL),are clinically available for the treatment of acquired bilateral nevus of Ota-like macules (ABNOM).However,no reliable evidence from large-scale comparative studies identifies which type of laser works best.This study aims to determine the differences in the effectiveness,complications,and risk factors of QSNYL,QSAL,and QSRL in the treatment of ABNOM,further to provide evidence for clinician to make optimal choice according to the condition of patients.Methods:We collected the data from 685 ABNOM patients,including clinical features,medical treatments,and follow-up,since 1999 to 2014.The Kruskal-Wallis test was used to compare therapeutic differences between the three groups.The risk factors were analyzed using univariate analysis (x2 test) and multivariate logistic regression analysis.Results:The overall treatment efficiency of the QSNYL group (52.5%) and QSAL group (51.9%) was higher than that of the QSRL group (39.5%) (x2 =17.468,P < 0.001).The onset time of the QSRL and QSAL groups was shorter than that of the QSNYL group.The factors influencing efficacy in the QSNYL group were age at first treatment,number of treatments,coexistence with melesma,and the presence of hyperpigmentation;in the QSAL group was the number of treatments;and in the QSRL group was the number of treatments and hyperpigmentation.The prevalence of hyperpigrnentation in the QSNYL group (30.5%) and the QSAL group (27.5%) was lower than that of the QSRL group (47.3%) (X2=6.576,P<0.001).Concluslon:The QSNYL,QSAL,and QSRL are all effective and safe treatments for ABNOM.Considering the overall efficacy,duration of treatment,side effects,and risk factors,the QSAL is an optimal choice for ABNOM treatment.展开更多
基金This research was funded by the Youth Foundation Project,Basic and Applied Research Foundation of Guangdong Province of China(2022A1515110780)China Postdoctoral Science Foundation(2023M743293)China Univerisity of Geosciences(Wuhan)Gemmological Institute research project(GICTXM-04-S202103).
文摘In gemmology,the term“Alexandrite effect”is used to describe colour change phenomenon when a gemstone is observed under different light sources,usually between daylight and incandescent light.The definition of the Alexandrite effect is constantly being broadened with new discovery of gem resource.The traditional definition of the Alexandrite effect attributing the colour change phenomenon to the presence of two maximum transmission regions and a maximum absorption region in the absorption spectra.In this study,7 blue spinels and 5 blue gemstones(including tanzanite,kyanite,fluorite,and 2 sapphires)showing the Alexandrite effect were investigated.The goal is to explain the cause of blue-to-violet Alexandrite effect and the spectral features causing such colour change.In the UV-Vis spectra,all samples showed a maximum absorption peak in the range of 534-610 nm,within the green region to orange region.The traditional explanation of green to red Alexandrite effect required a transmission window in the red region;however,some of our samples did not show this transmission window and the blue-to-violet Alexandrite effect was still visible.Therefore,it is incomplete to explain the mechanism of the Alexandrite effect according to their characteristic absorption spectra,a systematic study based on modern colour science and colour perception in human vision is required to elucidate the blue-to-violet Alexandrite effect.
基金Supported by Zhejiang Provincial Natural Science Foundation of China,No.LQ16H110001 and No.LQ13C100001Wenzhou Science and Technology Bureau Foundation,No.2017Y0750Medicine and Health Science and Technology Projects of Zhejiang Province of China,No.2013KYA128
文摘BACKGROUND We have previously proved that treatment of thick/deep infantile hemangiomas (IHs) with a long-pulse Alexandrite laser was clinically effective and safe. This article aims to investigate the efficiency of long-pulse Alexandrite laser use in treating thick and high-risk IHs located in particular anatomic areas and provides some new data on this issue. CASE SUMMARY A two-month-old girl with a thick and high-risk IH covering most of the right labia majora was examined in this study. The infant received four treatment sessions at 4- to 6-wk intervals with a long-pulse Alexandrite laser with settings as follows: 3 ms pulse duration, 8 mm spot size, 45 to 50 J/cm2 fluences, and dynamic cooling device (DCD) spray duration of 90 ms with a delay of 80 ms. Following each of the four treatment sessions, the IH showed a remarkable reduction in thickness and size without any sign of relapse. Ten months after the last treatment, the IH had completely regressed without adverse effects. During the laser treatment, no severe side effects were observed;blistering occurred only immediately after treatment and then scabbed over the next day, gradually improving in the following days. CONCLUSION Long-pulse Alexandrite laser treatment may be considered one of the first-line noninvasive therapeutic options for the treatment of thick IH.
文摘Background and Objective: Unwanted hair growth is a discomforting issue affecting both genders. People have tried various methods to get rid of this situation. This study aims to evaluate the efficacy and safety of a combined Alexandrite and Nd:YAG laser treatment for permanent hair removal, drawing insights from existing literature. Materials and Methods:This study included a total of 2127 patients (302 males, 1825 females) aged 18 - 65, with complete data, who underwent hair removal treatment between December 2018 and April 2021. These patients were treated using the Duetta laser system (Quanta system, Samarate, Italy), combining Alexandrite 755 nm and Nd:YAG 1064 nm wavelengths. The patients’ skin types were classified according to the Fitzpatrick classification scale. Target area/areas for laser hair removal was/were determined. Laser parameters, pulse counts, pain levels assessed through the Visual Pain Scale (VPS), and patient satisfaction were documented based on skin types. Findings: Across various skin types, Types I - II exhibited the highest treatment success rates (87%), with the axillary region achieving the highest rate (83%) and the face region achieving the lowest rate (75%). Pain scale analysis indicated that 98% of patients tolerated the procedure well. Patient satisfaction levels exceeded 90%. Evaluation of complication rates revealed minimal occurrences. Conclusion: The combined Alexandrite and Nd:YAG laser system demonstrates both efficacy and safety across diverse skin types, attributed to its notable success rates, minimal adverse effects, and high patient tolerance.
文摘Results of photoluminescence measurements for natural and synthetic alexandrite (BeAl2O4:Cr3+) are presented, where the samples are excited by the 488 nm line of an Ar+ laser, at different temperatures. The main issue is the analysis of the Cr3+ transition in the chrysoberyl matrix (BeAl2O4), with major technological application as active media for laser action. Results indicate anomalous behavior of Cr33+ transition depending on the measurement temperature. A simple model to explain the phenomena is suggested.
文摘The investigation of electrical properties in alexandrite (BeAl<sub>2</sub>O<sub>4</sub>:Cr<sup>3+</sup>) in synthetic and natural forms is presented in this paper. Alexandrite is a rare and precious mineral that changes color according to the light incident on it. In the synthetic form, it is used technologically as an active laser medium. The electrical characterization was obtained using the Thermally Stimulated Depolarization Current (TSDC) technique, an interesting tool to study the behavior of impurities in insulators. Alexandrite presented the electric dipole relaxation phenomenon, both in natural and in synthetic samples. It was possible to observe TSDC bands for the synthetic sample at around 170 K, and at around 175 K for the natural sample. Besides, photo-induced TSDC measurements were performed through the excitement of the samples by using a continuous wave argon laser. In addition, photoluminescence measurements were performed to verify in advance whether the laser light would be absorbed by the sample, and in order to complement the photo-induced TSDC measurements analysis. The results of photo-induced TSDC experiments have contributed to the understanding of the TSDC bands behavior: the results obtained with the technique suggest that there is an effective participation of Cr<sup>3+</sup> ions in the formation of TSDC bands because they were more intense when the sample was exposed to the argon laser beam.
文摘Peutz-Jeghers syndrome(PJS)is a polygenic autosomal dominant disease characterized by multiple gastrointestinal polyps and pigmentation of the mucosa and skin.While there are a few reports regarding successful treatment of intestinal polyps in PJS,there is little research regarding treatment of mucocutaneous melanosis.This study investigated the many advantages of using a Q-switched alexandrite laser to treat mucocutaneous melanosis.In this case,a 19-year-old male with PJS presented with labial lentigines and received two Q-switched alexandrite laser treatments in 2018.Subsequently,the efficacy of the treatment was evaluated.The result of the evaluation was that,after the two laser treatments,the labial lentigines were successfully removed,and there were no complications.
基金This work was supported by the Shanghai Municipal Natural Science under the Grant (97-181).
文摘In order to determine the appropriate treatment interval, 267 patients who underwent 3 sessions of treatment with Q-switched alexandrite laser were divided into 4 groups according to treatment interval, and their clinical responses were compared. Among them, 187 were asked about the process of pigment fading. Moreover, light and transmission electron microscopy were performed. It was noted that the clinical response of the 5 - 6 month interval group was significantly better than that of the 3 - 4 month group, but showed no significant difference from that of the 7 - 8 or ≥ 9 month group. 80.21% of investigated patients stated that marked pigment fading could no longer be observed 7 months after irradiation. 4 months after irradiation, the degenerated melanosomes and cell debris were still scattered among collagen fibers, scavenged gradually by macrophage. In conclusion, an appropriate treatment interval is 5 - 6 months.
基金Project supported by the National Natural Science Foundation of China.
文摘Ⅰ. INTRODUCTIONAlexandrite is a hopeful laser crystal not only because the sharp R-line shows laser action, as in ruby, but also the vibronic sideband is involved in the lasing of this crystal, in this case the system is of four-levels and is widely tunable （700 nm--800 nm）. We have studied the dynamic properties of the excited states of Cr<sup>3+</sup> in BeAl<sub>2</sub>O<sub>4</sub>. The relaxation of the system within the excited states reveals the dynamics of the interactions of the ion defects with phonons. As the time of relaxation
基金supported by grants from National Nature Science Foundation of China(No.81502739)Jiang Su National Nature Science Foundation(No.BK20150068)Medical Science and Technology Innovation Project of Chinese Academy of Medical Sciences(No.CIFMS-2017-I2M-1-017)
文摘Objective:Q-switched lasers,including 1064-nm Nd:YAG nansecond laser (QSNYL),755-nm alexandrite nanosecond laser (QSAL),and 694-nm nanosecond ruby laser (QSRL),are clinically available for the treatment of acquired bilateral nevus of Ota-like macules (ABNOM).However,no reliable evidence from large-scale comparative studies identifies which type of laser works best.This study aims to determine the differences in the effectiveness,complications,and risk factors of QSNYL,QSAL,and QSRL in the treatment of ABNOM,further to provide evidence for clinician to make optimal choice according to the condition of patients.Methods:We collected the data from 685 ABNOM patients,including clinical features,medical treatments,and follow-up,since 1999 to 2014.The Kruskal-Wallis test was used to compare therapeutic differences between the three groups.The risk factors were analyzed using univariate analysis (x2 test) and multivariate logistic regression analysis.Results:The overall treatment efficiency of the QSNYL group (52.5%) and QSAL group (51.9%) was higher than that of the QSRL group (39.5%) (x2 =17.468,P < 0.001).The onset time of the QSRL and QSAL groups was shorter than that of the QSNYL group.The factors influencing efficacy in the QSNYL group were age at first treatment,number of treatments,coexistence with melesma,and the presence of hyperpigmentation;in the QSAL group was the number of treatments;and in the QSRL group was the number of treatments and hyperpigmentation.The prevalence of hyperpigrnentation in the QSNYL group (30.5%) and the QSAL group (27.5%) was lower than that of the QSRL group (47.3%) (X2=6.576,P<0.001).Concluslon:The QSNYL,QSAL,and QSRL are all effective and safe treatments for ABNOM.Considering the overall efficacy,duration of treatment,side effects,and risk factors,the QSAL is an optimal choice for ABNOM treatment.
