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Breast cancer-related lymphedema (BCRL) is common among patients who have completed their cancer treatment. Although low-level laser therapy (LLLT) has been explored as a treatment option for BCRL, we could not find a regimen that is more effective than others. This meta-analysis aimed to organize existing research and determine the optimal combination of LLLT parameters for BCRL treatment. Studies were collected from four online databases: Embase, Ovid Medline, Cochrane, and Cinahl. The collected studies were reviewed by two of the authors. We focused on the aspects of the treatment area, treatment regimen, and total treatment sessions across the included studies. The comparisons between LLLT and non-LLLT were performed through a meta-analysis. Post-treatment QOL was significantly better in the axillary group. The group treated "three times/week with a laser density of 1.5–2 J/cm2" had significantly better outcomes in terms of swelling reduction, both immediately post-treatment and at 1–3 months follow-ups. The group with > 15 treatment sessions had significantly better post-treatment outcomes regarding reduced swelling and improved grip strength. According to these results, LLLT can relieve the symptoms of BCRL by reducing limb swelling and improving QOL. Further exploration found that a treatment approach targeting the axilla, combined with an increased treatment frequency, appropriate laser density, and extended treatment course, yielded better outcomes. However, further rigorous, large-scale studies, including long-term follow-up, are needed to substantiate this regimen. [ABSTRACT FROM AUTHOR]

BACKGROUND: Mesenchymal stem cells are pluripotent stromal cells isolated from a variety of tissues, which can differentiate into osteoblasts under certain conditions. Photobiomodulation, as an external stimulus, can promote osteogenic differentiation combined with other inducers or alone, providing new ideas for solving a series of bone diseases. OBJECTIVE: To review the relevant literature and mechanisms of photobiomodulation-induced osteogenic differentiation of mesenchymal stem cells, which will lay a theoretical foundation for bone tissue engineering using mesenchymal stem cells as seed cells and may offer some suggestions for future studies. METHODS: Relevant articles were searched on CNKI, PubMed and Wed of Science databases with Chinese search terms of “photobiomodulation, low power laser, low level laser, light-emitting diode, mesenchymal stem cells, osteogenic differentiation, biomaterials” and English search terms of “photobiomodulation, low level laser (light), light-emitting diode (LED), mesenchymal stem cell, osteogenic differentiation, biomaterials”. Finally, 88 articles were included for analysis. RESULTS AND CONCLUSION: (1) Photobiomodulation represented by low level laser and diode laser has a positive effect on promoting the proliferation and differentiation of mesenchymal stem cells. (2) Photobiomodulation can induce osteogenic differentiation of mesenchymal stem cells, whose feasibility has been verified in cell and animal experiments. On one hand, photobiomodulation can promote the expansion and differentiation of stem cells in vitro by activating related signaling pathways and up-regulating the expression of osteogenic molecules. On the other hand, photobiomodulation can improve the survival rate of stem cells in vivo, promote homing effect and shorten the healing time of bone defects after stem cells are injected into the body. However, photobiomodulation has a biphasic dose effect, whose laser parameters, experimental environment, cell type and other factors in various studies are different, making the research results lack consistency and difficult to apply in the clinic. (3) Combined with biological materials, other physical factors and drugs, photobiomodulation can also accelerate osteogenic differentiation. (4) In conclusion, photobiomodulation has been used increasingly widely in the medical field with its advantages of non-invasive, efficient and less-side reactions, and its role in bone tissue engineering has gradually become prominent, which provides a new method for the treatment of bone defects and related diseases. Further exploration should be focused on the standardized treatment parameters of photobiomodulation. [ABSTRACT FROM AUTHOR]

Nano‐scale laser beam size and its shape information are essential parameters in most optics‐based precision measurements and nano‐scale material processing. It is also quite challenging to measure nano‐size optical beams accurately for both open experiments and at compact workplace of microscope due to various instrumental factors. Outside of the visible spectrum, usually wavelength‐sensitive fluorescence markers and composite materials are used to read the laser beam profile. In this article, a cost‐effective carbon nano‐particles (CNPs) film has been developed from candle soot. Furthermore, the developed bio‐carbon soot film is encapsulated with optically transparent composite polymer on aqueous media to measure sub‐micron size spot of a low‐power laser. Field emission scanning electron microscopy, optical spectrum analysis, Fourier transform infrared spectroscopy, UV‐visible spectroscopy, differential scanning calorimetry and thermogravimetric analysis techniques have been performed to characterize the developed CNPs film and optimized its functionality. The fabricated film has been used to measure sub‐micron laser beam size. Due to the wide absorption spectrum of the developed bio‐CNPs film, the sensitivity region for measurement lies within both visible and beyond the visible spectrum. [ABSTRACT FROM AUTHOR]

Abstract Background Several systemic conditions can result in distinct degrees of salivary gland damage and consequent hypofunction. The development of successful management schemes is highly challenging due to the complexity of saliva. This study aimed to systematically map the literature on the physical stimulation of salivary glands for hyposalivation management and the response of individuals according to different systemic conditions causing salivary impairment. Methods A systematic search in the literature was performed. Two reviewers independently selected clinical trials, randomized or not, that used physical stimulation to treat hyposalivation caused by systemic conditions. Studies evaluating healthy subjects without hyposalivation were included as controls. Single-arm clinical studies or case series were also included for protocol mapping (PRISMA extension for scoping reviews). Results Out of 24 included studies, 10 evaluated healthy subjects, from which 9 tested transcutaneous electrical nerve stimulation (TENS) and 1 tested acupuncture and electroacupuncture. Fourteen studies evaluated individuals with hyposalivation: 6 applied TENS, 6 applied low-level laser therapy (LLLT), and 2 applied acupuncture, carried out in post-chemotherapy, medication use, postmenopausal women, hemodialysis patients, smokers, diabetics, Sjögren's syndrome (SS). All showed increased salivation after treatment, except for two LLLT studies in individuals with SS. Conclusions Among the different patient groups, individuals with Sjögren's syndrome (SS) exhibited the poorest responses, while those with medication-induced hyposalivation demonstrated the most favorable treatment outcomes, independently of the management strategy for saliva stimulation. It means that physical stimulation of salivary glands holds promise as an alternative for managing hyposalivation in cases of reversible gland damage. However, to make informed decisions in current practice, it is necessary to conduct new well-designed randomized clinical trials with appropriate methodologies.

Abstract Nano‐scale laser beam size and its shape information are essential parameters in most optics‐based precision measurements and nano‐scale material processing. It is also quite challenging to measure nano‐size optical beams accurately for both open experiments and at compact workplace of microscope due to various instrumental factors. Outside of the visible spectrum, usually wavelength‐sensitive fluorescence markers and composite materials are used to read the laser beam profile. In this article, a cost‐effective carbon nano‐particles (CNPs) film has been developed from candle soot. Furthermore, the developed bio‐carbon soot film is encapsulated with optically transparent composite polymer on aqueous media to measure sub‐micron size spot of a low‐power laser. Field emission scanning electron microscopy, optical spectrum analysis, Fourier transform infrared spectroscopy, UV‐visible spectroscopy, differential scanning calorimetry and thermogravimetric analysis techniques have been performed to characterize the developed CNPs film and optimized its functionality. The fabricated film has been used to measure sub‐micron laser beam size. Due to the wide absorption spectrum of the developed bio‐CNPs film, the sensitivity region for measurement lies within both visible and beyond the visible spectrum.

Background: Several systemic conditions can result in distinct degrees of salivary gland damage and consequent hypofunction. The development of successful management schemes is highly challenging due to the complexity of saliva. This study aimed to systematically map the literature on the physical stimulation of salivary glands for hyposalivation management and the response of individuals according to different systemic conditions causing salivary impairment. Methods: A systematic search in the literature was performed. Two reviewers independently selected clinical trials, randomized or not, that used physical stimulation to treat hyposalivation caused by systemic conditions. Studies evaluating healthy subjects without hyposalivation were included as controls. Single-arm clinical studies or case series were also included for protocol mapping (PRISMA extension for scoping reviews). Results: Out of 24 included studies, 10 evaluated healthy subjects, from which 9 tested transcutaneous electrical nerve stimulation (TENS) and 1 tested acupuncture and electroacupuncture. Fourteen studies evaluated individuals with hyposalivation: 6 applied TENS, 6 applied low-level laser therapy (LLLT), and 2 applied acupuncture, carried out in post-chemotherapy, medication use, postmenopausal women, hemodialysis patients, smokers, diabetics, Sjögren's syndrome (SS). All showed increased salivation after treatment, except for two LLLT studies in individuals with SS. Conclusions: Among the different patient groups, individuals with Sjögren's syndrome (SS) exhibited the poorest responses, while those with medication-induced hyposalivation demonstrated the most favorable treatment outcomes, independently of the management strategy for saliva stimulation. It means that physical stimulation of salivary glands holds promise as an alternative for managing hyposalivation in cases of reversible gland damage. However, to make informed decisions in current practice, it is necessary to conduct new well-designed randomized clinical trials with appropriate methodologies. [ABSTRACT FROM AUTHOR]

Advances in technology and the application of lasers in some areas of dentistry have increased over time. The low power laser has become an effective method for the relief of discomfort in orthodontic treatments. The objective of this research is to determine the usefulness of the therapeutic laser as a tool in the management of pain in orthodontic treatments. A search for scientific articles that mainly covered this topic was carried out in the databases: Google Scholar, Elsevier and the digital journals, American Journal of Orthodontics and Dentofacial Orthopedics, Tamé, the Angle Orthodontics in the period of January 2018 to March 2022. 1410 articles were found, of which 34 studies were chosen that included the use of laser in orthodontic treatments. Of the total selected, 13 were bibliographic review articles, 20 clinical trials and 1 case report. It was determined that the recommended wavelength for a favorable and relieving result to exist, in the areas of pain where the laser is applied, is 810 nm (nanometers) and that the laser sessions can be applied daily or intermittently. with a maximum irradiation of 10 seconds in each area of pain. A maximum of 20 sessions are indicated for the combination of laser orthodontic treatment. [ABSTRACT FROM AUTHOR]

Background: Nowadays, wound healing is one of the main problems of patients. Therefore, extensive research is underway to discover mechanisms associated with non-scarring of wounds. Using amniotic fluid and laser may potentially play a key role in wound healing and scar reduction due to its presence in tissue growth and repair agents. Aim: The present study evaluated the effect of Bovine Amniotic Fluid-derived cream (BFA) and Low-Power Laser (LPL) on accelerating skin wound healing and reducing scarring in an animal model. Methods: Therefore, 72 male Wistar rats were randomly divided into three groups (each group: 24). A wound 6 mm in diameter was then inflicted on the rats' backs. In the first group that was the control group, the wound was only used. Moreover, a BFA was implemented for the second group, and in the third group, LPL radiation was utilized. On the 1st and 3rd, 5th, 14th, and 21st days, the healing condition of the wound and scar created was examined. Results: Hence, evaluation of wound healing status on days 5 and 14 showed that the wound healing scale in the BFA group and LPL group was significantly better than the control group. On the 21st day, the average Scar Scoring Scale in the BFA and LPL groups was significantly lower than the control group. Histological images showed significant repair in the LPL and BFA groups. Conclusion: To conclude, considering the positive effect of LPL and BFA on wound healing and less scarring, it seems that LPL and BFA can heal wounds faster. Moreover, they can be used to prevent scarring after wound healing. [ABSTRACT FROM AUTHOR]

The present study sought to analyze the efficacy of the use of low power laser in the postoperative healing of abdominoplasty. To this end, this study aimed to verify the efficacy of the use of laser in postoperative healing of tummy tuck surgery. Thus, the methodology was a systematic review of an observational and descriptive nature. Articles were searched in the PEDro, Medline and PubMed databases, from 2004 to 2021. Result: 07 articles that brought the use of Laser and Low Power Interventions were analyzed to analyze their efficacy. Discussion: After a direct confrontation between each article, it was possible to analyze their specificities and main characteristics, bringing up the idea that the LPL is effective in the treatment of postoperative, concluding, still with the notion that in order to demonstrate its effectiveness, it is necessary more studies on the subject. [ABSTRACT FROM AUTHOR]

Introduction: the juvenile acne is common complaint in pediatric patients. Its therapy is a challenge for the dermatologist, since pharmacological treatments and physical procedures are combined; within them the laser shows encouraging results. Objective: determining the clinical course of pediatric patients with juvenile acne treated with low power laser. Methods: a descriptive, pre-experimental, longitudinal and prospective study was carried out. The sample was made up of 47 patients according to non-probabilistic sampling by criteria, and information collected through the interview and physical examination dermatologic, applied low - power laser for 15 sessions and treatment clinical evaluation was performed at the end. Results: predominated male age group of 16 to 18 years, the use of pretreatment with topical antibiotic, the skin phototype II, the papule as injury, the number of lesions 40 to 99, the clinical form of acne papulopustular and the face as the location of the lesions. In most patients are reduce the number of lesions present before treatment and achieved clinical outcome satisfactory. Minimal adverse events were identified. Conclusions: the study was demonstrate the beneficial effects of low power laser as a therapeutic modality in acne juvenile, what contribuye to improve the quality of dermatologic care in pediatric patients. [ABSTRACT FROM AUTHOR]

Background: Pain and discomfort are the most common sequel of orthodontic treatment both before and after separator placement. The aim of this study was to evaluate the effectiveness of low-level laser therapy (LLLT) on pain and discomfort control during separator placement before orthodontic fixed appliance placement. Materials and Methods: A single-blind, split-mouth clinical trial with a sample size of six patients (12 half mouths as cases where three positions on the buccal side of each tooth lased by the power of 1 Watt diode laser before orthodontic separator placement, while the other 12 teeth acted as control where separators were placed without laser application. Assessment of pain and discomfort was done by visual analog scale. The results of pain intensity and discomfort between the study group (EG) and the control group (CG) were compared by t-test and ANOVA, and the level of significance was set at a level at P ≤ 0.05. Results: The majority of the laser group experienced pain during chewing (85.70%) and most of them change their food habits (66.70%). In most of the lased cases (70%), pain intensity increased after 72 h, while among the control cases; it increased after 24 h (83.40%). There was a statistically significant difference in pain degree among the laser group at different time intervals (P = 0.05), while on the control group, statistically significant difference was found at baseline immediately after placement of orthodontic separator (P = 0.05). The majority of the patients' followed the instructions and did not take any medication to decrease pain intensity (66.70%). Conclusion: LLLT was effective in decreasing pain and discomfort during elastic separator placement for orthodontic patients with fixed appliances.

Introduction: The pain is the main symptom that patients refer after placing and activation of the orthodontic appliances. Objective: To evaluate the effectiveness of the low power laser for pain relief in patients with orthodontics treatment. Methods: A quasi-experiment study of therapeutic intervention was carried out in 30 patients that were in the beginnings of the distancing phase of the upper canine teeth (previous extraction of the same arch first premolars), who were assisted in the Orthodontics Service of Dr. Juan Bruno Zayas Alfonso Teaching General Hospital in Santiago de Cuba, from January to December, 2020. To such an effect, 2 groups were conformed at random, by arrival order, of 15 members each one: the study group that was treated with low power laser, and the control group that received paracetamol as usual analgesic. For the statistical validation of the information the percentage and the Student's t test were used for independent samples, with 95% of confidence. Results: There were significant differences as for the remission of pain intensity, because absence of this symptom or light pain was observed in all the members of the study group after three therapeutic sessions (p=0.00) while just 13.3 % of the control group patients was located in these two categories. Conclusions: It was demonstrated that the alternative therapy with laser was more effective to palliate the pain than the paracetamol. [ABSTRACT FROM AUTHOR]

Introduction: The low power laser has a wide use in the current medical practice. There is a great number of patients with acute or chronic conditions that can be treated with this therapy, with encouraging results, far better than those obtained with the use of conventional therapy. Objective: To evaluate the effectiveness of low power laser as adjuvant therapy to reduce the response time to pain relief in patients with zoster herpes. Methods: A quasi-experiment study of therapeutic intervention was carried out in 21 patients with zoster herpes. They were assisted in the Physical Medicine Service of the MININT Polyclinic in Santiago de Cuba, from January, 2016 to June, 2017. Two groups were conformed at random: the members of the first one received acyclovir, vitamins and lasertherapy (intervention); those of the second group received acyclovir, vitamins and analgesic (control). Results: It was observed that in the intervention group the intensity of the pain was diminishing in connection with the initial evaluation. This way, in the fifth session it was appreciated a higher percentage of patients with pain relief that in the control group, the same as in the tenth session and 21 days later, hence the effectiveness of the treatment. Conclusions: With the use of low power laser the patients with zoster herpes presented an improvement of the pain in less time, with a satisfactory response expressed in all of them, reason why its use is recommended as adjuvant therapy. [ABSTRACT FROM AUTHOR]

Copyright of Saúde Coletiva is the property of MPM Comunicacao and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Although carpal tunnel syndrome (CTS) is a common neuromuscular disorder, studies on its conservative treatment are inadequate and contradictory. OBJECTIVES: This study aimed to investigate and compare the effectiveness of low power laser therapy (LPLT) and Kinesio taping (KT) for the treatment of CTS. METHODS: Sixty patients with CTS were included in this study. One group received 15 sessions of KT, and the second group underwent 15 sessions of LPLT within three weeks. All patients were assessed with hand grip strength (HGS), Visual Analogue Scale (VAS)-pain, Douleur Neuropathique-4 (DN4) score, Boston Questionnaire (BQ), and electroneuromyography before and after treatment. RESULTS: Before treatment, all clinical and neurophysiological parameters were similar between the groups. After treatment, both groups significantly improved in terms of HGS, VAS-pain, DN4, and BQ. However, the LPLT group had significantly better HGS, VAS-pain, DN4, and BQ than the KT group. In addition, while median nerve motor distal latency and median nerve sensory conduction velocity improved significantly with treatment in both groups, the LPLT group's improvement was significantly better than that of the KT group. CONCLUSIONS: In patients with CTS, both LPLT and KT were effective treatments. However, the LPLT group had significantly better improvements than the KT group. [ABSTRACT FROM AUTHOR]

Background and Aim: Background and Aim: Photodynamic therapy is a minimally invasive approach to cancer, which is used to combine non-toxic photosensitizer and visible light to produce reactive oxygen species and destroy tumors. This study aimed to investigate the cytotoxicity effect of Graphene Oxide (GO)as an organic matter with many oxygen groups on photodynamic on destroying cancer cells. Materials and Methods: This study was performed on breast cancer cells (MCF-7) in vitro. The study groups included the first group of drug with different concentrations of graphene oxide (333.3, 285.7, 230.7, 166.6, 90.9, 47.6 µg/ml), the second group co-drug and laser light irradiation and the control group consisted of cells treated only with laser irradiation and the control group was treated with no treatment. Cells were exposed to visible laser irradiation (405 nm) at 0.1 W / cm2. Cell viability was determined by MTT assay. Ethical Considerations: This study with research ethics code SBU/S.1397.46A has been approved by research ethics committee at Shahid Behesht University of Tehran, Iran. Findings: The results of in vitro experiments showed that the dark toxicity of graphene oxide at concentrations of less than the 90.9 μg / ml concentration had no significant effect on cancer cells. Also, laser light alone don’t has toxic effect on cells. But graphene oxide-mediated dynamic light therapy has reduced the bioavailability of cancer cells on average by 21% over dark toxicity. Results are presented as mean of three independent replications, standard error, and p< 0.05 was considered significant. Conclusion: In this study, graphene oxide is fully biodegradable at concentrations below a certain value, but with increasing concentration, the toxicity effect increases. With exposure to light and graphene oxide, viability decreses that it is more effective for in vivio studies.

AIM: To compare the efficacy of intravitreal injection of ranibizumab plus low power 532 laser versus 532 laser alone for treating retinal vein occlusion(RVO)with macular edema complication.METHODS: Retrospective study of 48 patients diagnosed RVO complicated with macular edema from June 2017 to March 2018. Group A of 31 eyes(31 patients)were treated with intravitreal injection of ranibizumab plus low power 532 laser(the power is about 2/3 of the power of group B, about 100-130mw), and group B of 17 eyes(17 patients)were treated with 532 laser(the power is 150-200mw)alone. The best corrected visual acuity(BCVA), foveal retinal thickness(CMT), FFA and fundus were observed both before and after treatment at timepoint of 1mo, 2mo and 3mo between the two groups.RESULTS: In group A, BCVA was 0.84±0.02, 0.49±0.04, 0.29±0.04, 0.26±0.04 before and the 1, 2, 3mo after treatment. In group B, BCVA was 0.85±0.04, 0.58±0.01, 0.53±0.01, 0.53±0.02. The CMT value of group A before and after treatment was 527.5±17.59, 371±17.36, 298.5±32.87, 257.75±17.30μm, respectively. Group B was 535±16.36, 425±24.44, 420.25±17.70, 427.75±17.89μm. Intra-group comparison show statistical differences, group A had lower BCVA and CMT value than group B at the same time point(PPCONCLUSION: Both methods are effective in treating RVO with macular edema, improving vision, alleviating ME, and effectively controlling the disease.However, combined treatment can significantly reduce macular edema, improve vision, and be more stable than laser treatment alone.

This study aimed to evaluate the efficacy of diode laser in accelerating the healing process of ‎injured tendons and to determine the best ‎irradiation doses for impulse and continuous laser ‎irradiation. The semimembranosus muscle tendon of forty mature local breed rabbits ‎‎(Oryctolagus cuniculus) of both sexes was partially injured under ‎general anesthesia. The rabbits ‎were randomized into five groups and treated on the first day postoperatively. Group C served ‎as a control and ‎received no treatment, while groups A, B, and D were subjected to diode ‎impulse laser with a power of 2×10-3 watts and a wavelength of 904 ‎nm for 15, 25, and 35 ‎min per session, respectively. Group E received continuous diode laser for 30 min per ‎session with a power of 3×10-3 watts and a wavelength of 904 ‎nm. The treated groups received irradiation for 5, 8, ‎‎15, and 21 days postoperatively. Subsequent healing processes were ‎assessed macroscopically ‎and microscopically at each time point. In treated groups versus the control group, epitenon ‎thickness increased ‎from day 5, inflammatory and fibroblast cell responses were more evident, ‎and collagen fibers were clearer and more differentiated. On day 15, when the remodeling ‎stage began, group B healed best. The impulse diode laser was found to be more effective than ‎the ‎continuous diode laser in promoting the healing of surgical defects of the tendons at varying ‎degrees. In the continuous diode laser group, ‎there was a sustained high cellular response until ‎day 21 with the appearance of unorganized and irregular collagen fibers. This study ‎‎demonstrated that diode laser can accelerate the healing process of injured tendons and that ‎impulse diode laser is more effective than ‎continuous diode laser.

Background and Aim: Alopecia by reduction of hair follicles at the wound healing site is a complication of cryosurgery that creates an unpleasant appearance in the scar of healed tissue. The aim of this study was to evaluate the effect of low level laser on preventing necrosis of hair follicles and increasing hair follicles in cryosurgery induced wounds. Methods: Fifty male Wistar rats were randomly divided into 2 main experimental and control groups (with and without low power laser) and 5 subgroups. Histopathological examination of the amount of hair follicle count and angiogenesis at intervals of 3, 7, 14, 21 and 28 days was performed in the laboratory. SPSS software was used for statistical analysis. Results: There was no significant difference in the angiogenesis had significantly index between the main groups on days 14 and 21 (P>0.05), but on days 3, 7 and 28, the experimental group had significantly higher angiogenesis than the control group. Throughout the days, both groups showed a significant increase in angiogenesis (P<0.05), except for the third and seventh days in the control group, and in both groups between the 21st and 28th days (P>0.05). In the comparison of hair follicle index, there was an increase on all days, which was significantly higher in the experimental group than the control group (P<0.05). However, no statistical difference was observed between the third and seventh days (P>0.05). Conclusion: The use of low-power lasers on cryosurgery induced wounds with scars and alopecia can prevent hair follicles necrosis and subsequent increase in their numbers in rats. [ABSTRACT FROM AUTHOR]

Copyright of Odontología Pediátrica is the property of Asociacion Sociedad Peruana de Odontopediatria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, an experimental and numerical investigation of low power laser cutting of cotton fibre laminate (CFL) is presented. CFL is very useful for electrical insulation applications at low voltages, and usually used in gears, spacers and coil supports in turbine generator. Analysis of variance (ANOVA) along with Taguchi experimental design is conducted to determine the optimum levels of all input parameters; it is observed that heat-affected zone (HAZ) and kerf width are largely affected by the cutting speed and least affected by the stand-off distance (SOD). Detailed examination using SEM micrographs shows protruding fibres due to the polymeric matrix vaporization under laser processing. Additionally, it was noted that multiple beam passes produce a greater fibre pull-out than a single beam pass. In order to understand the underline physics, detailed numerical simulation of the problem is also performed in order to predict formation of heat-affected zone (HAZ), kerf width and thermal residual stress. Owing to fatigue, higher values of residual stresses result in cracking, delamination and failure. Using Abaqus software, user defined routines for defining laser beam profile and material removal are carried out for determining temperature gradient and cut characteristics. The approach for material removal uses element deletion based on temperature-dependent Hashin failure criteria when the fibres lose their strength at ablation point. The numerical results match reasonably well with the experimental measurements of HAZ and kerf width using the temperature-dependent material removal approach. [ABSTRACT FROM AUTHOR]

Photobiomodulation via a combination of different radiations can produce different effects on biological tissues, such as cell proliferation and differentiation, when compared to those produced via a single radiation. The present study aims to conduct a review of the literature addressing the results and applications of photobiomodulation induced by a combination of two or more radiations as well as their possible effects. PubMed was used to search for studies with restrictions on the year (< 50 years old) and language (English), including studies using human and animal models, either under healthy or pathologic conditions. Several studies have been conducted to evaluate the combination of different radiation effects on cells and biological tissues. Positive effects resulting from multiple-wavelength radiations could be attributed to different absorption levels because superficial and deep tissues could absorb different levels of radiations. Multiple-wavelength radiations from devices combining radiations emitted by low power lasers and light-emitting diodes could be a new approach for promoting photobiomodulation-induced beneficial effects. [ABSTRACT FROM AUTHOR]

Purpose: Osteoarthritis is one the most common chronic diseases of the joints that mostly affects knee joint. Low power laser is one the minimally invasive treatments of osteoarthritis. However, the efficacy of this therapy is still controversial. This study aimed to evaluate the efficacy of low power laser therapy in reducing pain and increasing knee range of motion compared to placebo laser. Methods: This study was a double-blind clinical trial performed at a day clinic in Tehran, Iran, from March 2016 to February 2017. Treatment for both groups comprised 10 sessions, 5 times a week. In this study, low power laser with a wavelength of 810 nm and a power of 100 mW at 8 points was applied around the knee during two weeks of treatment. At the same time, laser was applied in the placebo group, but the power output was zero. Data analyses were performed by repeated measures ANOVA test using SPSS version 20. Results: The mean pain score at rest (P=0.691), as well as at activity (P=0.751) were not significantly different between the two groups. The range of motion of knee flexion (P=0.435), and the range of motion of knee extension (P=0.885) showed no significant difference between two groups. Both interventions over time lead to a significant change in pain at rest and at activity and also increase in the range of motion in knee flexion and extension (P

Breast cancer-related lymphedema (BCRL) is common among patients who have completed their cancer treatment. Although low-level laser therapy (LLLT) has been explored as a treatment option for BCRL, we could not find a regimen that is more effective than others. This meta-analysis aimed to organize existing research and determine the optimal combination of LLLT parameters for BCRL treatment. Studies were collected from four online databases: Embase, Ovid Medline, Cochrane, and Cinahl. The collected studies were reviewed by two of the authors. We focused on the aspects of the treatment area, treatment regimen, and total treatment sessions across the included studies. The comparisons between LLLT and non-LLLT were performed through a meta-analysis. Post-treatment QOL was significantly better in the axillary group. The group treated "three times/week with a laser density of 1.5-2 J/cm 2 " had significantly better outcomes in terms of swelling reduction, both immediately post-treatment and at 1-3 months follow-ups. The group with > 15 treatment sessions had significantly better post-treatment outcomes regarding reduced swelling and improved grip strength. According to these results, LLLT can relieve the symptoms of BCRL by reducing limb swelling and improving QOL. Further exploration found that a treatment approach targeting the axilla, combined with an increased treatment frequency, appropriate laser density, and extended treatment course, yielded better outcomes. However, further rigorous, large-scale studies, including long-term follow-up, are needed to substantiate this regimen., (© 2023. The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.)

Background and Aim: Background and Aim: Photodynamic therapy is a minimally invasive approach to cancer, which is used to combine non-toxic photosensitizer and visible light to produce reactive oxygen species and destroy tumors. This study aimed to investigate the cytotoxicity effect of Graphene Oxide (GO)as an organic matter with many oxygen groups on photodynamic on destroying cancer cells. Materials and Methods: This study was performed on breast cancer cells (MCF-7) in vitro. The study groups included the first group of drug with different concentrations of graphene oxide (333.3, 285.7, 230.7, 166.6, 90.9, 47.6 μg/ml), the second group co-drug and laser light irradiation and the control group consisted of cells treated only with laser irradiation and the control group was treated with no treatment. Cells were exposed to visible laser irradiation (405 nm) at 0.1 W / cm2. Cell viability was determined by MTT assay. Ethical Considerations: This study with research ethics code SBU/S.1397.46A has been approved by research ethics committee at Shahid Behesht University of Tehran, Iran. Findings: The results of in vitro experiments showed that the dark toxicity of graphene oxide at concentrations of less than the 90.9 μg / ml concentration had no significant effect on cancer cells. Also, laser light alone don’t has toxic effect on cells. But graphene oxide-mediated dynamic light therapy has reduced the bioavailability of cancer cells on average by 21% over dark toxicity. Results are presented as mean of three independent replications, standard error, and p< 0.05 was considered significant. Conclusion: In this study, graphene oxide is fully biodegradable at concentrations below a certain value, but with increasing concentration, the toxicity effect increases. With exposure to light and graphene oxide, viability decreses that it is more effective for in vivio studies. [ABSTRACT FROM AUTHOR]

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Exposure of cells to genotoxic agents causes modifications in DNA, resulting to alterations in the genome. To reduce genomic instability, cells have DNA damage responses in which DNA repair proteins remove these lesions. Excessive free radicals cause DNA damages, repaired by base excision repair and nucleotide excision repair pathways. When non-oxidative lesions occur, genomic stability is maintained through checkpoints in which the cell cycle stops and DNA repair occurs. Telomere shortening is related to the development of various diseases, such as cancer. Low power lasers are used for treatment of a number of diseases, but they are also suggested to cause DNA damages at sub-lethal levels and alter transcript levels from DNA repair genes. This review focuses on genomic and telomere stabilization modulation as possible targets to improve therapeutic protocols based on low power lasers. Several studies have been carried out to evaluate the laser-induced effects on genome and telomere stabilization suggesting that exposure to these lasers modulates DNA repair mechanisms, telomere maintenance and genomic stabilization. Although the mechanisms are not well understood yet, low power lasers could be effective against DNA harmful agents by induction of DNA repair mechanisms and modulation of telomere maintenance and genomic stability. [ABSTRACT FROM AUTHOR]

To evaluate the effect of aPDT on S. mutans and C. albicans present in the dental biofilm, using methylene blue as a photosensitizer in different pre-irradiation times. The searches were made on Pubmed, Web of Science, Bireme, Scopus and Cochrane Library, and were complemented by screening the references of selected articles in the attempt to find any article that did not appear in the database search. The searches were performed by two researchers and limited to studies involving human subjects published in the English language. Inclusion criteria included in vitro studies with aPDT; studies that used methylene blue as a photosensitizer; studies that used low power laser; studies that evaluated S. mutans or C. albicans . Studies published in a non-English language, patents, in vivo or in situ studies; case reports, serial case, reviews and animal studies were not included. Studies published before 1996 were also not included. Initially, the search resulted in 68 published studies. 16 records were excluded because they were duplicated. The analysis of titles and abstracts resulted in the exclusion of 48 of the published studies, resulting in 4 studies included in the systematic review. The aPDT was effective in three of the four papers selected for the systematic review and the pre-irradiation time used was 5 or 15 min. This therapy had satisfactory results in both C. albicans and S. mutans when using methylene blue as a photosensitizer. [ABSTRACT FROM AUTHOR]

Background: According to the World Health Organization (WHO) reports, the number of patients with diabetes will be doubled by 2050 to reach 250 million. This study aimed to assess the effect of low-power laser, with power of 5 mW, wavelength of 632.8 nm and energy of 4 j/cm2, on wound healing and blood sugar of normal and diabetic rats. Methods: 36 male rats, weighing 200 to 250 g, were divided into 4 groups including 9 animals in each group. Groups I and II were considered as two control groups. Group I was the control group without skin wound (normal control) and group II with skin wound (sham operated) treated using laser. Group III was considered as diabetic with skin wound, and group IV with skin wound treated by low-power laser with a wavelength of 632.8 nm and a power of 5 mW. In the time scales of 4, 7 and 10 days after surgery, the wound area was measured to calculate wound healing. Blood sugar levels and urine hydroxyproline were measured via colorimeter. Findings: The wound healing in the 7th day of treatment in both second (healthy laser) and forth (diabetic laser) group was significant in comparison with the control group (P < 0.05 and P < 0.01, respectively). On the 10th day, wound healing showed significant difference in the mentioned two groups (P < .0.05 for both) and third group (P < 0.01) in comparison with the control group. Conclusion: The laser treatment in the wavelength of 632.8 nm, power of 5 mW and energy of 4 j/cm2 showed significant effect on blood sugar levels and wound healing in a time-dependent manner in both normal and diabetic rats. Laser healing effects was confirmed using both histological and biochemical studies on hydroxyproline concentration in the treated groups.

Background and Aims : Free gingival graft is one of the most predictable procedures for gingival augmentation, but patient’s discomfort and pain during healing period of palatal donor site is a significant concern. The aim of this study was to evaluate the effect of 660nm low power laser on pain and healing in palatal donor sites. Materials and Methods: The present split mouth randomized controlled clinical trial was performed in 12 patients at the department of periodontics of Tehran University of Medical Sciences. Patients’ allocation was done by balanced block randomization (laser group and placebo group). In laser test group (wave length: 660 nm, power: 200mW, time of irradiation: 32s) was applied immediately post-surgery and in day 1, 2, 4 and 7 after that. In the control group, laser application was done with off power mode. Evaluation of epithelialization and healing was done with H2O2 and photograph. The number of palliative pills and bleeding was recorded. Wilcoxon test was used to analyze healing during the study. Patient’s pain during study was analyzed using repeated measure ANOVA. Mc Nemar test was used to analyze bleeding. Level of statistical significance was set at 0.05. Results: Laser group showed better epithelialization (P=0.02) and healing (P=0.01) in day 14 after surgery and showed better epithelialization in day 21(P=0.05). No statistically differences were observed between laser group and control group in terms of bleeding and medication (P=0.51), (P=1). Conclusion: According to the results of this study, the low power laser can promote palatal wound healing during the second and third week after free gingival graft procedures.

Introduction: a variety of studies has shown that low-power laser stimulates osteogenesis. The mechanisms proposed for the biostimulating effect of the laser involve increased ATP synthesis and formation of reactive oxygen species (ROS) by mitochondria. These EROs, including hydrogen peroxide, act on cell signaling and influence the regulation of gene expression, leading to cellular responses at hours or even days after irradiation. Peroxiredoxins (Prxs) constitute a family of abundant enzymes capable of breaking down hydrogen peroxide. Objective: a literature review was carried out on the biostimulating effects of low power laser on oxidative stress during the cicatrization process. Material and Methods: a search of the PubMed and Scielo databases was carried out in recent years, following inclusion and exclusion criteria, using as descriptors peroxirredoxin, low power laser and osteoblasts. Results: fifty full-text articles were identified that fit the inclusion and exclusion criteria. As for the types of Peroxirredoxins, Prxs I and IV were highlighted. Conclusion: In light of the information gathered in the literature, we conclude that the mechanisms of action of the laser induce the formation of EROs, and we also stress the importance of establishing safe parameters in the laser application so that the desired effects of biostimulation are achieved and that toxic effects are avoided. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to conduct a systematic review of the literature published from 2000 to August 2015, to investigate the effect of photobiomodulation (PBM) therapy on dentoalveolar-derived mesenchymal stem cells (ddMSCs), assessing whether a clear conclusion can be reached from the data presented. Background data: Systematic reviews provide the best evidence on the effectiveness of a procedure and permit investigation of factors that may influence the performance of a method. To the best of our knowledge, no previous systematic review has evaluated the effects of PBM only on ddMSCs. Methods: The search was conducted in PubMed /MEDLINE®, Scopus and Web of Science databases, and reported according to the Preferred Reporting Items for Systematic Reviews and Metaanalyses (PRISMA Statement). Original research articles investigating the effects of PBM therapy on ddMSCs, published from 2000 to August 2015, were retrieved and used for this review according to the following eligibility criteria: evaluating PBM therapy, assessing stem cells of dentoalveolar origin, published in English, dealing with cells characterized as stem cells, and using light that did not need external chromophores. Results: From the initial 3467 potentially relevant articles identified, 6 were excluded because they were duplicates, and 3453 were considered ineligible based on the inclusion criteria. Therefore, eight articles remained, and these were fully analyzed in order to closely check exclusion criteria items. Only one of them was excluded because the cultured cells studied were not characterized as stem cells. Finally, seven articles served as the basis for this systematic review. Conclusions: PBM therapy has no deleterious effects on ddMSCs. Although no other clear conclusion was obtained because of the scarce number of publications, the results of these studies are pointing to an important tendency of PBM therapy to improve ddMSCs' viability and proliferation. [ABSTRACT FROM AUTHOR]

There is just one study about the effects of 830 nm low power laser (LPL) on conduction velocity of sural nerve in human. Considering the fact that the sural nerve is a pure sensory nerve, therefore, for determining the effect of LPL on electrophysiological parameters of the nerve in human, this study was carried out as a base for further basic and clinical researches. Thirty eight normal volunteer men participated (20–35 yr.) in this study. LPL (670 and 780 nm) was applied on left and right sural nerves. Electrophysiological parameters such as Onset Latency (OL), Peak Latency (PL), Negative Peak Amplitude (NPA), Peak to Peak Amplitude (PPA) and Duration were measured before and after the application of various doses (0.5, 1.5 and 2.5 J/cm²( of LPL. This study showed that both wavelengths of LPL increase the latencies and therefore reduce the nerve conduction velocity (NCV). In addition, LPL application decreased the nerve amplitudes. Among the various intensities, the application of 2.5 J/cm² was the most effective (P< 0.001). On the other hand, 670 nm wavelength and 2.5 J/cm² had the greatest effects on OL in comparison with 780 nm (P< 0.04). However, there was no significant difference between the effects of 670 and 780 nm on the other electrophysiological parameters of sural nerve.

Pain reduction and surgical wound healing enhancement have several advantages. Wound healing is a complex and organized phenomenon. During this phenomenon, definite and harmonized processes such as: reconstruction, immigration parenchyma and connective tissue cells proliferation and re-construction of gingival connective tissue take place. Studies show that lower power laser (He-Ne) can induce different biological changes in ceils through biochemical mechanisms. Considering the therapeutic effects of (He-Ne) low power laser radiation on healing processes, cell proliferation, connective tissue fibers and finally the acceleration of gingival wound healing were studied. This study was done on 50 mature and healthy rats with the average weight of 250 to 300 grams, and 3 to 4 months old. After anesthesia, maxillary wounds, with the same size, were made in all samples and they were randomly divided into control and test groups. After surgery, rats of test group received laser radiation with the value of 5 mJ/cm3 every day for a period of 5 days. And on the 5lh day, they were killed. Gingival biopsy was performed and histological study was done. The number of fibroblasts, collagens, endothelial ceils and blood vessels were counted. In test group, the granulation tissue was more active and the edema and inflammation were lesser than those of the control group. Data were analyzed by t-test method and PO.05 was significant. So, it is concluded that periodical radiation of (He-Ne) low power laser has an important role on surgical gingival wounds.

This paper introduces a novel technique for repairing defective soldering joints in densely packed printed circuit boards and multichip modules. The new technique is not based on conventional soldering methods or tools, but rather on the remarkable properties of gold nanoparticles. Gold nanoparticles are deposited on the surface of the solder pad or joint that must be reworked, and a low-power laser with a wavelength in the range of 500–800 nm is directed to the area where the gold nanoparticles are present. The nanoparticles absorb the electromagnetic radiation at such wavelengths very effectively, and intense surface plasmons are generated in the nanoparticles. The surface plasmons cause the nanoparticles to heat up, where the temperature can reach several hundred degrees of Celsius. This in turn causes the solder that is in contact with the nanoparticles to melt, while other solder joints in the vicinity remain unaffected. The narrow wavelength range of 540–572 was determined to be the optimal range of wavelengths for the present application. [ABSTRACT FROM PUBLISHER]

In addition to the major functions performed by in the cell, mitochondria play a major role in cell-light interaction. Accordingly it is generally accepted that mitochondria are crucial in cell photobiomodulation; however a variety of biomolecules themselves proved to be targets of light irradiation. We describe whether and how mitochondria can interact with monochromatic and narrow band radiation in the red and near IR optical regions with dissection of both structural and functional effects likely leading to photobiostimulation. Moreover we also report that a variety of biomolecules localized in mitochondria and/or in other cell compartments including cytochrome c oxidase, some proteins, nucleic acids and adenine nucleotides are light sensitive with major modifications in their biochemistry. All together the reported investigations show that the elucidation of the mechanism of the light interaction with biological targets still remains to be completed, this needing further research, however the light sensitivity of a variety of molecules strongly suggests that photobiomodulation could be used in both in photomedicine and in biotechnology. [ABSTRACT FROM AUTHOR]

Background and Aims: Free gingival graft is one of the most predictable procedures for gingival augmentation, but patient's discomfort and pain during healing period of palatal donor site is a significant concern. The aim of this study was to evaluate the effect of 660nm low power laser on pain and healing in palatal donor site. Materials and Methods: The present split mouth randomized controlled clinical trial was performed in 12 patients in the department of periodontics in Tehran University of Medical Sciences. Patients' allocation was done by balanced block randomization (laser group and placebo group). In laser test group (wave length: 660 nm, power: 200mW, time of irradiation: 32s) was applied immediately post-surgery and in day 1, 2, 4 and 7 after that. In the control group, laser application was done with off power mode. Evaluation of epithelialization and healing was done with H2O2 and photograph. Number of palliative pills and bleeding was recorded. Wilcoxon test was used to analyze healing during the study. Patient's pain during study was analyzed using repeated measure ANOVA. Mc Nemar test was used to analyze bleeding. Level of statistical significance was set at 0.05. Results: Laser group showed better epithelialization (P=0.02) and healing (P=0.01) in day 14 after surgery and showed better epithelialization in day 21(P=0.05). No statistically differences were observed between laser group and control group in terms of bleeding and medication. Conclusion: According to the results of this study, low power laser can promote palatal wound healing during second and third week after free gingival graft procedures. [ABSTRACT FROM AUTHOR]

Abstract: Laser phototherapy emerges as an alternative or auxiliary therapy for acute ischemic stroke, traumatic brain injury, degenerative brain disease, spinal cord injury, and peripheral nerve regeneration, but its effects are still controversial. We have previously found that laser phototherapy immunomodulates the response to focal brain damage. Following direct cortical cryogenic injury the effects of laser phototherapy on inflammation and repair was assessed after cryogenic injury (CI) to the central nervous system (CNS) of rats. The laser phototherapy was carried out with a 780nm AlGaAs diode laser. The irradiation parameters were: power of 40mW, beam area of 0.04cm2, energy density of 3J/cm2 (3s) in two points (0.12J per point). Two irradiations were performed at 3h-intervals, in contact mode. Rats (20 non-irradiated – controls and 20 irradiated) were used. The wound healing in the CNS was followed in 6h, 1, 7 and 14days after the last irradiation. The size of the lesions, the neuron cell viability percentages and the amount of positive GFAP labeling were statistically compared by ANOVA complemented by Tukey’s test (p <0.05). The distribution of lymphocytes, leukocytes and macrophages were also analyzed. CI created focal lesions in the cortex represented by necrosis, edema, hemorrhage and inflammatory infiltrate. The most striking findings were: lased lesions showed smaller tissue loss than control lesions in 6h. During the first 24h the amount of viable neurons was significantly higher in the lased group. There was a remarkable increase in the amount of GFAP in the control group by 14days. Moreover, the lesions of irradiated animals had fewer leukocytes and lymphocytes in the first 24h than controls. Considering the experimental conditions of this study it was concluded that laser phototherapy exerts its effect in wound healing following CI by controlling the brain damage, preventing neuron death and severe astrogliosis that could indicate the possibility of a better clinical outcome. [Copyright &y& Elsevier]

Abstract: Brain injury is responsible for significant morbidity and mortality in trauma patients, but controversy still exists over therapeutic management for these patients. The objective of this study was to analyze the effect of phototherapy with low intensity lasers on local and systemic immunomodulation following cryogenic brain injury. Laser phototherapy was applied (or not-controls) immediately after cryogenic brain injury performed in 51 adult male Wistar rats. The animals were irradiated twice (3h interval), with continuous diode laser (gallium–aluminum–arsenide (GaAlAs), 780nm, or indium–gallium–aluminum–phosphide (InGaAlP), 660nm) in two points and contact mode, 40mW, spot size 0.042cm2, 3J/cm2 and 5J/cm2 (3s and 5s, respectively). The experimental groups were: Control (non-irradiated), RL3 (visible red laser/ 3J/cm2), RL5 (visible red laser/5J/cm2), IRL3 (infrared laser/3J/cm2), IRL5 (infrared laser/5J/cm2). The production of interleukin-1IL-1β (IL-1β), interleukin6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor-α (TNF-α) was analyzed by enzyme immunoassay technique (ELISA) test in brain and blood samples. The IL-1β concentration in brain of the control group was significantly reduced in 24h (p <0.01). This reduction was also observed in the RL5 and IRL3 groups. The TNF-α and IL-6 concentrations increased significantly (p <0.01 and p <0.05, respectively) in the blood of all groups, except by the IRL3 group. The IL-6 levels in RL3 group were significantly smaller than in control group in both experimental times. IL-10 concentration was maintained stable in all groups in brain and blood. Under the conditions of this study, it is possible to conclude that the laser phototherapy can affect TNF-α, IL-1β and IL-6 levels in the brain and in circulation in the first 24h following cryogenic brain injury. [Copyright &y& Elsevier]

This study aimed to investigate the influence of low-power gallium-aluminium-arsenide (GaAlAs) laser [830 nm, continuous wave (CW), 40 mW and fluence 4 J/cm(2)] on the healing of surgically created bone defects in rats treated with bioactive glass graft material. Surgical bone defects were created in the mandibles of 36 Wistar rats divided into two groups, each consisting of 18 rats. Group I was treated with bioactive glass plus laser irradiation. Group II was treated with graft material only. The animals were killed at 4 weeks, 8 weeks and 12 weeks postoperatively for histological examination. Laser irradiation had significantly accelerated bone healing at 4 weeks and 8 weeks in comparison with that at the sites not irradiated. However at 12 weeks, complete healing of the defects had occurred with no difference detected. Our results have confirmed the positive effect of soft laser in accelerating bone regeneration. [ABSTRACT FROM AUTHOR]