• Medical Lasers
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• 제9권2호
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• pp.119-125
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• 2020

Photobiomodulation forms the basis of photomedicine and is defined as the effect of coherent or non-coherent light sources, such as low-level lasers and light-emitting diodes, on cells and tissues. This treatment technique affects cell functions, proliferation, and migration, and plays an important role in tissue regeneration. Mesenchymal stem cells (MSCs) are known to be beneficial for tissue regeneration, and the combination of stem cell therapy and laser therapy appears to positively affect treatment outcomes. In general, a low-power laser has a positive effect on MSCs, thereby facilitating improvements in different disease models. This study elucidates the mechanisms and effects of low-power laser irradiation on the proliferation, migration, and differentiation of various MSCs that have been examined in different studies.

• Medical Lasers
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• 제10권3호
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• pp.132-137
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• 2021

The effects of low-level laser irradiation on cells and tissues, known as photobiomodulation therapy (PBMT), are the basis of photomedicine. Several investigations have evaluated the therapeutic effects of PBMT for neuronal regeneration and differentiation in animal models and humans. Recently, intranasal PBMT (iN-PBMT) has shown potential as a treatment method for neurologic disorders. In this review, we have summarized the various modes of iN-PBMT delivery and their application in the treatment of brain disorders.

• Journal of Korean Dental Science
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• 제2권1호
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• pp.42-47
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• 2009

Objective : The purpose of this study was to evaluate the effects of low level lasers on bone healing and new bone formation around titanium dental implants in canine models. 18 oxidized surface treated implants and a Dens-bio laser were used. Study design : Low level lasers were irradiated with a total of 8J for 4 minutes by pulse wave type and 1 minute by continuous type. For the experimental group, a low level laser was used to irradiate the first premolar implant's insertion area at the time of insertion, a low level laser was used to irradiate the second premolar implant's insertion area daily for one week after implant insertion, and a low level laser was used to irradiate the third molar implant's insertion area daily for 2 weeks postoperatively. At the conclusion of the study, sacrificed tissue sections were made from investing tissue and observed under an optical microscope. Results : The rate of new bone formation around the implant showed no significant difference between the control group and the experimental group. New bone formation rates of the control and experimental group 2 weeks following implant placement were higher than that of immediately after implant placement and 1 week after implant placement. Conclusions : Based on these results, a low-level laser showed no statistically significant increase in bone formation following implant placement.

• Journal of Periodontal and Implant Science
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• 제40권3호
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• pp.105-110
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• 2010

Purpose: It has been reported that low-level semiconductor diode lasers could enhance the wound healing process. The periodontal ligament is crucial for maintaining the tooth and surrounding tissues in periodontal wound healing. While low-level semiconductor diode lasers have been used in low-level laser therapy, there have been few reports on their effects on periodontal ligament fibroblasts (PDLFs). We performed this study to investigate the biological effects of semiconductor diode lasers on human PDLFs. Methods: Human PDLFs were cultured and irradiated with a gallium-aluminum-arsenate (GaAlAs) semiconductor diode laser of which the wavelength was 810 nm. The power output was fixed at 500 mW in the continuous wave mode with various energy fluencies, which were 1.97, 3.94, and 5.91 $J/cm^2$. A culture of PDLFs without laser irradiation was regarded as a control. Then, cells were additionally incubated in 72 hours for MTS assay and an alkaline phosphatase (ALPase) activity test. At 48 hours post-laser irradiation, western blot analysis was performed to determine extracellular signal-regulated kinase (ERK) activity. ANOVA was used to assess the significance level of the differences among groups (P<0.05). Results: At all energy fluencies of laser irradiation, PDLFs proliferation gradually increased for 72 hours without any significant differences compared with the control over the entire period taken together. However, an increment of cell proliferation significantly greater than in the control occurred between 24 and 48 hours at laser irradiation settings of 1.97 and 3.94 $J/cm^2$ (P<0.05). The highest ALPase activity was found at 48 and 72 hours post-laser irradiation with 3.94 $J/cm^2$ energy fluency (P<0.05). The phosphorylated ERK level was more prominent at 3.94 $J/cm^2$ energy fluency than in the control. Conclusions: The present study demonstrated that the GaAlAs semiconductor diode laser promoted proliferation and differentiation of human PDLFs.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 하계학술발표회
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• pp.74-75
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• 2000

The past few decades have witnessed the development of very robust technique, known as magneto-optical trap(MOT), for cooling and trapping of neutral atoms using lasers and magnetic fields. This technique can easily produce cooled atoms to a temperature range of nano-kelvin $s^{(1)}$ . These laser cooled and trapped atoms have found applications in various fields, such as ultrahigh resolution spectroscopy, precision atomic clocks, very cold atomic collision physics, Bose-Einstein Condensation, the Atom laser, etc. Particularly, a few isolated atoms of very low temperature are needed in the cavity QED studies in the optical regime. One can obtain such atoms from a MOT using the atomic fountain technique. The widely used technique for atomic fountain is, first to cool and trap the neutral atoms in MOT. And then launch them in the vertical (1, 1, 1) direction with respect to cooling beams, using moving molasses technique. Recently, this technique combined with the cavity-QED has opened an active area of basic research. This way atoms can be strongly coupled to the optical radiation in the cavity and leads to various new effects. Trapping of single atom after separating it from MOT in the high Q-optical cavity is actively initiated presentl $y^{(2.3)}$. This will help to sharpen our understanding of atom-photon interaction at quantum level and may lead to the development of single-atom laser. Our efforts to develop an $^{85}$ Rb-atomic fountain is in progress. (omitted)

• Medical Lasers
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• 제10권3호
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• pp.138-145
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• 2021

Low-level laser therapy or photobiomodulation (LLLT/PBM) therapy has been widely applied to enhance and accelerate the recovery of oral mucositis. This study investigates the documented effect of LLLT on oral mucositis caused by chemotherapy. This review appraises 6 animal studies and 12 clinical studies published in the Pubmed database during the past 10 years, related to the application of LLLT for the treatment of mucositis. Despite varied parameters and diverse conditions, the assessed articles indicate that application of LLLT on oral mucositis using near-infrared wavelengths is prophylactic, reduces pain, and enables a rapid recovery. Various combined treatments were also identified among the published papers, which further establishes the efficacy of LLLT as a viable treatment.

• 한국산업융합학회 논문집
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• 제25권6_3호
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• pp.1147-1154
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• 2022

Now that the development of autonomous driving is progressing, LiDAR has become an indispensable element. However, LiDAR is a device that uses lasers, and laser side effects may occur. One of them is the much-talked-about eye-safety, and developers have been satisfying this through laser characteristics and operation methods. But eye-safety is just one of the problems lasers pose. For example, irradiating a laser with a specific energy level or higher in a dusty environment can cause deterioration of the dust particles, leading to a sudden explosion. For this reason, the dust ignition proof regulations clearly state that "a source with a pulse period of less than 5 seconds is considered a continuous light source, and the average energy does not exceed 5 mJ/mm 2 or 35 mW" [2]. Energy of output optical power is limited by the law. In this way, the manufacturer cannot define the usage environment of the LiDAR, and the development of a LiDAR that can be used in such an environment can increase the ripple effect in terms of use in application fields using the LiDAR. In this paper, we develop a LiDAR with low optical power that can be used in environments where high power lasers can cause problems, evaluate its performance. Also, we discuss and present one of the directions for the development of LiDAR with laser power limited by dust ignition proof regulations.

• 대한한의학회지
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• 제22권3호
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• pp.11-20
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• 2001

Objective: As early as 1967, professor Endre Mester's group published the first scientific report concerning the effects of low level laser therapy (LLLT) on the skin of rats. After that, there have been some two thousand research reports from many countries in which the biological effects of low level lasers have been demonstrated. We reviewed some theses about LLLT published in Korea recently, and we make a proposal concerning the new method of study using LLLT in Oriental Medicine. Methods: We have selected 12 medical theses about low level laser therapy published in Korean Oriental Medicine journals recently, reviewed them, and investigated their methods. Results and Conclusion: There were several clinical studies in Korea about hyperlipidemia, hypercholesteremia, hyperfibrinogenemia, hyperlipoproteinemia, headache, dizziness, stroke, pain and numbness published from 1996 to 2000 using LLLT. The number of theses of good quality is showing a tendency to increase, recently. Sooner or later LLLT will be a very useful treatment and we believe that it will be an alternative useful method in Oriental Medical fields. There have been some negative public opinions about LLLT voiced in the Korean Oriental Medical society recently, but we expect a positive re-evaluation of this new treatment within Oriental Medicine in the near future.

• Medical Lasers
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• 제10권1호
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• pp.15-21
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• 2021

As technology advances at a rapid rate, innovations in regenerative medicine will eventually include the use of energy-based therapeutics, such as low intensity-pulsed ultrasound stimulation (LIPUs), pulsed electromagnetic field stimulation (PMFs), and low-level laser/light therapy (LLLt) or photobiomodulation therapy (PBMt). Among these treatments, LLLt/PBMt attracted significant attention by the turn of the century, as evidenced by the numerous publications compared to LIPUs and PMFs, particularly for augmented bone regeneration (ABR). This is a testament of how the maturation of technology and scientific knowledge leads to latent compounded applications, even when the value of a technique is reliant on empirical data. This article reviews some of the notable investigations using LLLt/PBMt for bone regeneration published in the past decade, focusing on how this type of therapy has been utilized together with the existing regenerative medicine landscape.

• Physical Therapy Rehabilitation Science
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• 제6권4호
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• pp.170-175
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• 2017

Objective: The anti-inflammatory effects of low-level laser in burn wound model in rats were investigated. Design: Randomized controlled trial. Methods: The rats were assigned to three experimental groups. Group I received second-degree burn wounds; Group II received dressing film and low-level laser ($1.2J/cm^2$) treatment after a burn wound; Group III received dressing film and low-level laser ($2.3J/cm^2$) treatment after a burn wound. After inducing a deep second-degree burn wound, the wound was observed every day and the burn area diameter and retraction quantification at 1, 7, and 14 days were evaluated. Low-level laser was investigated on hematological parameters after 14 days. Effects of low-level laser on the inflammatory cytokines (tumor necrosis $factor-{\alpha}$ [$TNF-{\alpha}$] and interleukin-6 [IL-6]) concentrations in the serum were evaluated using immunosorbent assay kits. Results: Group III showed a significant difference in wound size on days 7 and 14 compared to Group I (p<0.05). Group II showed a significant difference in wound size on day 14 compared to Group I (p<0.05). For wound contraction percentage, both laser therapy treatment groups showed a significant difference compared with Group I (p<0.05). There was also a significant difference in wound contraction percentage in Group III compared to Group II (p<0.05). Compared with the model control group, decreased $TNF-{\alpha}$ and IL-6 levels in the serum was observed at 14 days after burn wound induction. Conclusions: The results of this study suggest that low-level laser therapy can assist in burn wound healing, which might be associated with decreased concentrations of $TNF-{\alpha}$ and IL-6 related proinflammatory cytokines.