Use of Laser in Sleep Disorders: A Review on Low Laser Uvulopalatoplasty

Study Objective. The objective of this study is to find the effectiveness of the low laser therapy on uvulopalatoplasty/soft palate in sleep apnea patients and snoring. Also, this study aims to touch base on the effectiveness of the Er:YAG and combined use of Er:YAG and Nd:YAG lasers for the uvulopalatoplasty. Methods. A comprehensive and systematic literature review was conducted using PubMed, Google Scholar, Cochrane Central Register of Controlled Trials, Embase, Web of Science, the US National Institutes of Health Trials Registry, WHO Library, and Medline. The search strategies were developed to cover publications from January 2010 through March 2020. The past 10 years of the search were performed to report the data following systematic review and meta-analysis protocol (PRISMA-P) 2015 statement. Results. With the help of keywords, the total number of abstracts identified was 946. These abstracts were further reviewed as per inclusion and exclusion criteria, and 106 abstracts were identified to match the selection criteria. Further review of full articles resulted in 12 articles that matched the inclusion criteria for the study. Conclusion. Er:YAG can be a good alternative and least invasive therapy for managing snoring and obstructive sleep apnea. Er:YAG therapy is considered to nonsurgical intervention with minimum side effects and can be performed chairside.

Laser Processing of Asteroid Simulants

<p>Asteroid mining and redirection are two trends that both can utilize lasers, one to drill and cut, the other to ablate and move. Yet little is known about what happens when a laser is used to process the types of materials we typically expect to find on most asteroids. To shed light on laser processing of asteroid material, we used pulsed Nd:YAG lasers on samples of olivine, pyroxene, and serpentine, and studied the process with a high-speed camera and illumination laser at 10~000~frames~per~second. We also measure the sizes of the resulting holes using X-ray micro-tomography to find the pulse parameters which remove the largest amount of material using the least amount of energy. We find that at these power densities, all three minerals will melt and chaotically throw off spatter. Short, low-power pulses can efficiently produce thin, deep holes, and long, high-power pulses are more energy efficient at removing the most amount of material. We wil also present some preliminary results of the effects of spallation of these materials.</p>

Effects of Co2 and Nd:YAG Laser Remelting of the Ti6Al4V Alloy on the Surface Quality and Residual Stresses

The titanium alloys are materials susceptible to tribological wear and the laser treatment can be applied in surface treatment processes to obtain for example higher hardness level. From the other side, it is important to take into consideration, that hardness increase that can be connected with cracks. The aim of this research was to investigate the effects of different lasers and the process parameters on the form and level of residual stresses in the Ti6Al4V alloy, which determine the initiation and propagation of cracking. Two lasers were used, the CO2 and Nd:YAG lasers. The specimens were remelted in liquid nitrogen, water or calm air at different pre-heating temperature. The different laser power and scan rates were applied. The increase in energy density increased the number of cracks, the change of an environment and pre-heating affected alo the surface cracking. The cracks observed after remelting with Nd:YAG laser were longer than those observed after treatment with CO2 laser. The compressive stresses after the CO2 laser treatment, and tensile stresses after treatment with the Nd:YAG laser, were found. The appearance of cracks was attributed to an excessive energy density. The different distribution of heat energy inside and around the laser tracks was discussed as the origin of presence either tensile or compressive stresses in the alloy treated with different lasers.