Nd:YAG water mist laser treatment for giant gestational gingival tumor: A case report

BACKGROUND This case of gestational gingival tumor is huge and extremely rare in clinical practice.As the growth location of this gingival tumor is in the upper anterior tooth area,it seriously affects the pregnant woman's speech and food,causing great pain to the patient.The use of Nd:YGA water mist laser to remove the gingival tumor resulted in minimal intraoperative bleeding,minimal adverse reactions,and good postoperative healing,which is worthy of clinical promotion and application.CASE SUMMARY The patient,a pregnant woman,reported a large lump in her mouth on the first day of postpartum treatment.Based on medical history and clinical examination,the diagnosis was diagnosed as gestational gingival tumor.Postoperative pathological biopsy also confirmed this diagnosis.The use of Nd:YAG water mist laser to remove the tumor resulted in minimal intraoperative bleeding,clear surgical field of view,short surgical time,and good postoperative healing.CONCLUSION In comparison to traditional surgery,Nd:YAG water mist laser surgery is minimally invasive,minimizes cell damage,reduces bleeding,ensures a clear field of vision,and virtually eliminates postoperative edema,carbonization,and the risk of cross infection.It has unique advantages in oral soft tissue surgery for pregnant patients.Therefore,the clinical application of Nd:YAG water mist laser for the treatment of gestational gingival tumors is an ideal choice.

Clinical usefulness of transpapillary removal of common bile duct stones by frequency doubled double pulse Nd:YAG laser

AIM: To study the efficacy and the safety of laser lithotripsy without direct visual control by using a balloon catheter in patients with bile duct stones that could not be extracted by standard technique. METHODS: The seventeen patients (7 male and 10 female; mean age 67.8 years) with difficult common bile duct (CBD) stones were not amenable for conventional endoscopic maneuvers such as sphincterotomy and mechanical lithotripsy were included in this study. Laser wavelengths of 532 nm and 1064 nm as a double pulse were applied with pulse energy of 120 mJ. The laser fiber was advanced under fluoroscopic control through the ERCP balloon catheter. Laser lithotripsy was continued until the fragment size seemed to be less than 10 mm. Endoscopic extraction of the stones and fragments was performed with the use of the Dormia basket and balloon catheter. RESULTS: Bile duct clearance was achieved in 15 of 17 patients (88%). The mean number of treatment sessions was 1.7 ± 0.6. Endoscopic stone removal could not be achieved in 2 patients (7%). Adverse effects were noted in three patients (hemobilia, pancreatitis, and cholangitis). CONCLUSION: The Frequency Doubled Double Pulse Nd:YAG (FREDDY) laser may be an effective and safe technique in treatment of difficult bile duct stones.

Multipulse Nd:YAG Laser Thomson Scattering Diagnostics on HT-7 Tokamak

A multipulse Nd：YAG （Neodym-yttrium aluminium garnet） laser Thomson scattering diagnostic system developed was recently applied on HT-7 tokamak to obtain more accurate electron temperatures. A CAMAC-based real-time computer system for laser control, data acquisition, analysis and calibration was investigated in detail. Furthermore, the reliability and accuracy of this diagnostic system were demonstrated by comparing the results with those of a soft-X ray diagnostic system.

芪参补气活血养颜汤联合Q开关Nd∶YAG激光治疗女性黄褐斑的美学效果观察

目的:探讨芪参补气活血养颜汤联合Q开关Nd∶YAG激光治疗女性黄褐斑的美学效果。方法:选取笔者医院2019年1月-2022年1月收治的80例黄褐斑女性作为研究对象,按照随机数字表法分为观察组42例(采用芪参补气活血养颜汤联合Q开关Nd∶YAG 1064 nm激光治疗)和对照组38例(采用Q开关Nd∶YAG 1064 nm激光治疗)。观察两组的临床疗效,中医症状积分,皮肤状况,黄褐斑面积及颜色,不良反应发生率。结果:治疗后,观察组患者的总有效率为97.62%,高于对照组患者的84.21%(P<0.05)。治疗后,观察组患者情绪低落、胸胁胀痛、经行乳胀、口苦咽干等上述中医症状积分均低于对照组患者(P<0.05)。治疗后,观察组黑素指数、红斑指数及皱纹指数均低于对照组(P<0.05)。治疗后,观察组黄褐斑面积及颜色评分均低于对照组(P<0.05)。治疗后,观察组患者的总不良反应发生率与对照组患者比较差异无统计学意义(P>0.05)。结论:芪参补气活血养颜汤联合Q开关Nd∶YAG1064 nm激光能够提高黄褐斑治疗的临床疗效,改善患者临床症状,改善皮肤状况,减少黄褐斑面积及颜色,安全性较高,值得临床推广。

Pulsed Nd:YAG laser cladding of high silicon content coating on low silicon steel

A pulsed Nd：YAG （yttrium aluminum garnet） laser-based technique was employed to clad low silicon steel with preplaced Si and Fe mixed powders for high Si content. The surface morphology, microstructural evolution, phase composition, and Si distribution, within the obtained cladding coatings, were characterized by optical microscopy （OM）, field emission scanning electron microscopy （FE-SEM）, with associated energy dispersive spectroscopy （EDS）, transmission electron microscopy （TEM）, and X-ray diffraction （XRD）. The microhardness was also measured along the depth direction of the specimens, A crack- and pore-free cladding coating through excellent metallurgical bonding with the substrate was successfully prepared on low silicon steel by means of optimized single-track and multi-track laser cladding. The phases of the coating are a-Fe, T-Fe, and FeSi. The high microhardness of the lasercladding zone is considered as an increase in Si content and as the refined microstructure produced by the laser treatment. The Si contents of the cladding coatings were about 5.8wt% in the single-track cladding and 6.5wt% in the multi-track cladding, respectively.

Experimental study of electro-optical-switched pulsed Nd:YAG laser

We report the specification of a compact and stable side diode-pumped Q-switched pulsed Nd：YAG laser. We ex- perimentally study and compare the performance of the pulsed Nd：YAG laser in the free-running and Q-switched modes at different pulse repetition rates from 1 Hz to 100 Hz. The laser output energy is stabilized by using a special configu- ration of the optical resonator. In this laser, an unsymmetrical concave-concave resonator is used and this structure helps the mode volume to be nearly fixed when the pulse repetition rate is increased. According to the experimental results in the Q-switched operation, the laser output energy is nearly constant around 70 mJ with an FWHM pulse width of 7 ns at 100 Hz. The optical-to-optical conversion efficiency in the Q-switched regime is 17.5%.

Controlled Laser Transformation Hardening of Martensitic Stainless Steel by Pulsed Nd:YAG Laser

Laser transformation hardening （LTH） was applied to the surface of the AISI 420 martensitic stainless steel by a pulsed Nd：YAG laser to obtain optimum hardness. The influences of process parameters （laser pulse energy, duration time, and travel speed） on the depth and hardness of laser treated area were investigated. Image analysis of SEM microstructure of AISI 420 showed that plate-like carbide have almost fully and （30-40）% of globular carbide particles dissolved into the matrix after laser transformation hardening by pulsed laser and the microstructure was refined to obtain controlled tempered martensite microstructure with 450 VHN hardness.

LD环状侧面均匀泵浦Nd∶YAG激光振荡器

激光二极管(Laser Diode,LD)环状侧面均匀泵浦的激光振荡器具有结构简单、光束质量高、单脉冲能量大等特点,常常在高能脉冲固体激光器中作为主振荡功率放大(MOPA)结构的振荡器,一直是国内外科研人员研究的重要方向之一。本论文通过Zemax软件对不同激光二极管排列方式以及不同工作物质吸收系数对吸收光场的影响的进行了仿真。基于仿真结果,设计了一种20个bar条串联的环状侧面泵浦结构,以提高晶体吸收的均匀性。通过该环状侧泵结构,结合超高斯非稳腔设计,搭建了一种双棒串接激光振荡器进行实验研究。该振荡器实现了在100 Hz重复频率下,单脉冲能量为496 mJ、脉冲宽度为12.4 ns的1064 nm激光输出,光束质量优于9 mm·mrad,光-光转换效率为18.5%。并且该振荡器可以维持光轴稳定不变的同时,实现20 ns脉宽以内变档可调。实验结果证明了该环状侧面均匀泵浦结构可靠有效,为MOPA结构振荡器选取提供了一种有效的方案。

Pump pulse characteristics of quasi-continuous-wave diode-side-pumped Nd:YAG laser

The influence of pumping laser pulse on the property of quasi-continuous-wave(QCW)diode-side-pumped Nd:YAG laser is investigated theoretically and experimentally.Under remaining a fixed duty cycle,the average output power increases,and the corresponding thermal focal length shorten with the increase of the pump pulse duration,which attributes to the decrease of the ratio of pulse buildup time to the pulse duration.At a pump power of 146 W,the laser output power changes from 65.1 W to 81.2 W when the pulse duration is adjusted from 150μs to 1000μs,confirming a significant enhancement of 24.7%.A laser rate equation model incorporating the amplified spontaneous emission is also utilized and numerically solved,and the simulated results agree well with the experimental data.

A 526 mJ Subnanosecond Pulsed Hybrid-Pumped Nd：YAG Laser

A hybrid-pumped Nd：YAG pulse laser with a double-pass two-rod configuration is presented. The focal length of offset lens is particularly studied to compensate for the thermal lens effect and depolarization. For input pulse energy of 141 μJ with pulse duration of 754ps, the pulse laser system delivers 526mJ pulse energy and 728ps pulse width output at lO Hz with pulse profile shape preservation. The energy stability of the laser pulse is less than 3%, and the beam quality factor M2 is less than 2.26.

Structural and Optical Properties of Ce^(3+), Yb^(3+) Co-doped YAG Films by Pulsed Laser Deposition

Ce3＋, Yb3＋ co-doped Y3Al5O12 films were prepared by pulse laser deposition. X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescence spectra were used to characterize their structural and luminescent properties. Near-infrared quantum cutting from the films was observed via a cooperative energy transfer from Ce3＋ to Yb3＋ ions. The high quantum efficiency of the films implies that Ce3＋,Yb3＋ co-doped Y3A15O12 films have potential application by tuning the solar spectrum to enhance the efficiency of silicon solar cells.

双波长LD泵浦Nd^(3+)∶YAG免温控被动调Q激光器的研究

传统的固体激光器体积、重量大,功耗高,限制了其在空间受限设备中的应用。被动调Q的LD泵浦免温控固体激光器省去了复杂的温度控制装置,调Q机构简单,能够满足复杂温度环境的特殊应用场景的小型化、低功耗要求。提出了基于双波长LD泵浦实现宽温度范围免温控阈值自适应的1.06μm激光脉冲输出方法。基于Nd∶YAG晶体设计了角锥棱镜谐振腔,仿真分析了LD泵浦源到激光棒的面心距对热负载的影响,并确定4 mm的最佳面心距。数值分析了相同泵浦功率下-40~60℃温度范围内激光静态能量输出变化,以及不同初始透过率的可饱和吸收体对激光阈值脉宽的影响。计算结果表明在-37℃~60℃范围内,阈值脉宽都在200μs以下,阈值脉宽最低点达到了29.4μs。构建主波实时探测的阈值自适应调节装置并搭建实验系统,实验结果表明,在温度范围为-35~60℃时,阈值脉宽变化范围为40~180μs。采用激光腔体一体加工成型,应用轻量化的铝合金材料,实现工程化应用,体积83.5 mm×44 mm×29.5 mm,重量约为230 g。在23.8%初始透过率的饱和吸收体条件下实现单脉冲输出能量42 mJ,脉冲宽度5.2 ns。

COLLIDING PULSE MODE-LOCKED Nd:YAG AND Nd:PHOSPHATE GLASS LASERS

Using pentamethylidyne dye as a saturable absorber,we have obtained pulses close to Fourier-transform limit from colliding pulse mode-locked Nd:YAG and Nd:phosphate glass lasers with minim pulse durations of 8 psec and 3.7 psec,respectively.

Timing Jitter and Pulse Width Reduction in a Hybrid Q-Switched Cr,Nd：YAG Laser

We present a detailed study of a combined actively and passively Q-switched （CAPQ） laser with an acousto-optic modulator （AOM） and a codoped Cr^4＋, Nd^3＋ ：YAG crystal The hybrid Q-switch approach is used to produce a short laser pulse with stable and tunable repetition rates. The timing jitter, average pulse width, and average pulse amplitude vary periodically with the AOM modulation frequency under a fixed pump power. The repetition rate of the CAPQ laser can be turned approximately from 4 kHz to 16 kHz with the jitter less than 400 ns.

Opto-Electronic Investigation of Wet Coating Deposition of ITO Nanopowders on Flexible Substrate Using Pulse Nd-YAG Laser

Transparent thin layer indium tin oxide was coated on polyethylene tetraphetalate (PET) substrate by means of spin coating process and its opto-electronic properties have been investigated. The surface treated by pulse Nd-YAG laser. Pulse frequency, duration and energy were, 1000 Hz, 0.2 to 20 ms and 25 to 40 J respectively. The effect of treatment on crystallization, optical properties and bonding processes of the thin layer was investigated. The results show that ITO coated on flexible PET substrates is conductive and transparent. The sheet transparency for a 350 nm thickness in the visible range is more than 83.6%. Using Nd-YAG laser increased conductivity by a factor of 100 times and causes higher bonding performances.

低通量Q开关Nd∶YAG激光联合微针导入氨甲环酸治疗黄褐斑

目的评估低通量Q开关Nd∶YAG(QSNY)激光单一治疗与其联合微针导入氨甲环酸治疗黄褐斑的疗效差别,并基于皮肤镜分型分析不同类型黄褐斑的最佳治疗方式。方法收集2022年1月—2023年12月就诊的黄褐斑患者的临床资料,比较QSNY激光单一治疗组(对照组,23例)与QSNY激光联合微针导入氨甲环酸治疗组(联合组,23例)治疗3次后改良黄褐斑面积和严重程度指数(mMASI)评分、皮肤镜检查总评分(TDS)、医生临床评估(PGA)和不良反应的发生率。结果2组患者治疗后mMASI评分均降低,联合组的mMASI评分改善优于对照组(P<0.05);2组患者治疗后TDS均降低,联合组改善程度更佳,差别有统计学意义(P<0.05)。与治疗前比较,联合组治疗后毛细血管扩张明显改善,差别有统计学意义(P<0.001)。2组患者的PGA评分比较,差别无统计学意义(P>0.05)。2组患者治疗后均未发现明显的不良反应。结论QSNY激光联合微针导入氨甲环酸治疗黄褐斑的疗效优于单一激光治疗,前者对血管增生和表皮色素沉着明显的黄褐斑更有利。

腔外旋转泵浦的Nd∶YAG固体激光器研究

固体激光器的热管理仍然是高功率激光系统发展的一个持续挑战。在激光系统中增益介质和泵浦光之间引入相对运动是一种高效的热管理方案。针对静止泵浦,旋转增益介质泵浦以及泵浦光旋转泵浦3种泵浦方式,借助有限元数值模拟方法分析了Nd∶YAG晶体的温度分布。泵浦光以800 r/min旋转时,在35 W泵浦功率下,使用标准的热沉冷却技术,晶体的最高温度达到约36℃,仅增加约16℃,这远低于静止泵浦时的142℃。实验设计并演示了一种腔外旋转泵浦的Nd∶YAG激光器,得到了12.2 W的1 064 nm连续输出,斜率效率为37.2%,这大于静止时的35.1%,实验结果与理论结果相符合。研究表明,腔外旋转泵浦的固体激光器拥有高效的热管理。

Nd∶YAG和Er∶YAG激光联合辅助治疗伴2型糖尿病的慢性牙周炎的临床疗效分析

纳入合并2型糖尿病的慢性牙周炎患者30例,采用分口设计法,将同患者左侧牙列设为试验组,行牙周基础治疗,以及Nd∶YAG和Er∶YAG激光联合辅助治疗,右侧牙列设为对照组,仅行牙周基础治疗。治疗前后检测牙周及CBCT影像指标,并行组间比较。治疗前2组全部指标无统计学差异(P>0.05)。治疗后3个月,试验组的出血指数(BI)和探诊深度(PD)明显低于对照组(P<0.05);治疗后6个月,试验组的BI、PD以及附着丧失(AL)明显低于对照组,牙槽骨内剩余牙根表面积和牙根体积明显高于对照组(P<0.05)。Nd∶YAG和Er∶YAG激光联合辅助下的牙周基础治疗较单纯牙周基础治疗对伴2型糖尿病的慢性牙周炎疗效更为显著。

后发性白内障患者行Nd∶YAG激光术后视觉质量

目的:探究角膜/屈光分析仪OPD-Scan Ⅲ评估后发性白内障患者行Nd∶YAG激光术后视觉质量。方法:回顾性研究。选取2021-05/2023-04于我院行Nd∶YAG激光后囊膜切开术治疗的后发性白内障患者98例98眼,采用角膜/屈光分析仪OPD-Scan Ⅲ获取患者高阶像差参数(彗差、球差和三叶草像差)和视觉质量参数[斯特列尔比(SR)和人眼调制传递函数(MTF)曲线中4 mm面积比(AR)],比较患者术前,术后1 wk,3 mo时视力、高阶像差和视觉质量。结果:纳入患者手术前后裸眼远视力(UDVA)、裸眼中视力(UIVA)、裸眼近视力(UNVA)、彗差、球差、三叶草、SR和AR比较均有差异(均P<0.001)。术后1 wk,3 mo UDVA、UIVA、UNVA、彗差、球差、三叶草、SR和AR与术前比较均有差异(均P<0.05)。术后3 mo UDVA、UIVA、UNVA、SR和AR与术后1 wk比较均有差异(均P<0.05),术后3 mo彗差、球差、三叶草与术后1 wk比较均无差异(均P>0.05),术后3 mo球差、三叶草与SR均呈负相关(r_(s)=-0.427,P=0.009;r_(s)=-0.436,P=0.010),三叶草与AR呈负相关(r_(s)=-0.406,P=0.015)。结论:后发性白内障患者Nd∶YAG激光术后视力改善,使用角膜/屈光分析仪OPD-Scan Ⅲ系统反映患者视觉质量具有较高的临床价值。

Nd∶YAG激光周边虹膜切开对PACG急性发作期眼压的影响及安全性观察

目的 探究Nd∶YAG激光周边虹膜切开对原发性闭角型青光眼(PACG)急性发作期的治疗效果及安全性。方法 前瞻性选取2020年1月至2022年1月在首都医科大学附属北京世纪坛医院接受治疗的PACG急性发作期患者102例作为研究对象,按照随机数字表法将其分为研究组和对照组,每组各51例。对照组予以传统药物进行诊治,研究组接受Nd∶YAG激光周边虹膜切开治疗。记录并比较两组患者的术前,术后1、3、6、12个月眼压变化,术前,术后1、3、6、12个月疼痛视觉模拟评分法(VAS)评分、角膜内皮细胞[平均面积(AVE)、最大面积(MAX)、最小面积(MIN)、细胞密度(CD)、面积变异系数(CV)、面积标准偏差(SD)]变化,治疗后视野、房角情况以及并发症发生情况。结果 研究组患者术后1、3、6、12个月的眼压分别为(17.55±2.09)、(17.56±2.04)、(17.89±2.16)、(18.33±2.98)mmHg,均低于对照组[(19.87±1.98)、(20.55±1.78)、(17.89±2.16)、(18.33±2.98)mmHg],差异均有统计学意义(P<0.05)。研究组患者术后1、3、6、12个月的VAS评分分别为(4.03±0.64)、(3.22±0.15)、(2.31±0.14)、(1.99±0.13)分,均低于对照组[(4.66±0.74)、(3.55±0.12)、(2.98±0.11)、(2.32±0.15)分],差异均有统计学意义(P<0.05)。术后1个月,研究组患者的CD、CV、AVE、SD均高于对照组,MAX、MIN、六角形细胞百分数均低于对照组,差异均有统计学意义(P<0.05)。研究组患者治疗后视野缺损进展、开放角度减小发生率分别为3.92%、7.84%,均低于对照组(17.65%、23.53%),房角增大、开放角度>5°发生率分别为90.20%、62.75%,均高于对照组(45.10%、13.73%),差异均有统计学意义(P<0.05)。随访期内,两组患者发生高眼压、眼角膜水肿、眼前房渗出、眼前房出血情况及总并发症发生率比较,差异均无统计学意义(P>0.05)。结论 对于PACG急性发作期的患者,Nd∶YAG激光周边虹膜切开治疗较传统药物治疗在眼压控制、疼痛缓解以及视野缺损进展和房角变化等方面具有更显著的效果,且安全性较好,是一种有效且安全的PACG急性发作期治疗手段。