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Sample records for helium-neon laser prevents

  1. Molecular Iodine Fluorescence Using a Green Helium-Neon Laser

    Science.gov (United States)

    Williamson, J. Charles

    2011-01-01

    Excitation of molecular iodine vapor with a green (543.4 nm) helium-neon laser produces a fluorescence spectrum that is well suited for the upper-level undergraduate physical chemistry laboratory. Application of standard evaluation techniques to the spectrum yields ground electronic-state molecular parameters in good agreement with literature…

  2. Helium Neon laser therapy for post mastectomy lymphedema and ...

    African Journals Online (AJOL)

    The aim of this work was to evaluate the efficacy of Helium Neon (He–Ne) laser therapy on post mastectomy lymphedema and shoulder mobility. Thirty female patients with axillary lymph node dissection (ALND), with or without radiotherapy had been participated in this study. The patients were randomly divided into two ...

  3. Low energy Helium-Neon laser in the prevention of oral mucositis in patients undergoing bone marrow transplant: results of a double blind randomized trial.

    Science.gov (United States)

    Cowen, D; Tardieu, C; Schubert, M; Peterson, D; Resbeut, M; Faucher, C; Franquin, J C

    1997-07-01

    To evaluate the efficiency of Helium-Neon (He-Ne) laser in the prevention of oral mucositis induced by high dose chemoradiotherapy before autologous bone marrow transplantation (BMT). Between 1993 and 1995, 30 consecutive patients receiving an autologous peripheral stem-cell or bone marrow transplant (BMT) after high dose chemoradiotherapy were randomized to possibly receive prophylactic laser to the oral mucosa after giving informed consent. Chemotherapy consisted of cyclophosphamide, 60 mg/kg intravenously (I.V.) on day (d)-5 and d-4 in 27 cases, or melphalan 140 mg/kg I.V. on d-4 in three cases. Total body irradiation (TBI) consisted of 12 Gy midplane dose in six fractions (4 Gy/day for three days). He-Ne laser (632.8 nm wavelength, power 60 mW) applications were performed daily from d-5 to d-1 on five anatomic sites of the oral mucosa. Oral examination was performed daily from d0 to d + 20. Mucositis was scored according to an oral exam guide with a 16 item scale of which four were assessed by the patients themselves. Mean daily self assessment scores for oral pain, ability to swallow and oral dryness were measured. A daily mucositis index (DMI) and a cumulative oral mucositis score (COMS) were established. Requirement for narcotics and parenteral nutrition was recorded. The COMS was significantly reduced among laser treated (L+) patients (p = 0.04). The improvement of DMI in L+ patients was also statistically significant (p parenteral nutrition was not reduced (p = NS). Helium-Neon laser treatment was well tolerated, feasible in all cases, and reduced high dose chemoradiotherapy-induced oral mucositis. Optimal laser treatment schedules still needs to be defined.

  4. Helium-neon laser improves skin repair in rabbits.

    Science.gov (United States)

    Peccin, Maria Stella; Renno, Ana Claudia Muniz; de Oliveira, Flavia; Giusti, Paulo Ricardo; Ribeiro, Daniel Araki

    2012-12-01

    The purpose of this study was to evaluate the influence of helium-neon laser on skin injury in rabbits. For this purpose, 15 New Zealand rabbits underwent bilateral skin damage in leg. Helium-neon laser light, at a fluence of 6 J∕cm2 and wavelength of 632.8 nm, was applied on the left legs (laser group). The right leg lesions (control group) served as negative control. All sections were histopathologically analyzed using HE sections. The results showed little infiltration of inflammatory cells, with proliferation of fibroblasts forming a few fibrous connective tissue after 1 week post-injury. The lesion on the 3rd week was characterized by granulation tissue, which formed from proliferated fibrous connective tissue, congested blood vessels and mild mononuclear cell infiltration. On the 5th week, it was observed that debris material surrounded by a thick layer of connective tissue and dense collage, fibroblasts cells present in the dermis covered by a thick epidermal layer represented by keratinized epithelium. Taken together, our results suggest that helium-neon laser is able to improve skin repair in rabbits at early phases of recovery.

  5. Effect of low level helium-neon (He-Ne) laser therapy in the prevention & treatment of radiation induced mucositis in head & neck cancer patients.

    Science.gov (United States)

    Arun Maiya, G; Sagar, M S; Fernandes, Donald

    2006-10-01

    Oral mucositis is a common debilitating complication of radiotherapy occurring in about 60 per cent of cancer patients. Considerable buccal toxicity of radiotherapy or chemotherapy in cancer patients to become discouraged and can affect their quality of life. In addition, such toxicity can alter the treatment plan. At present, there is no clinically appropriate prophylaxis efficacious antidote for mucositis. The low level laser (LEL) appears to be a simple, non-traumatic technique for the prevention and treatment of radiation induced mucositis. Therefore the present study was carried out to find out the effect of low-level helium-neon (He-Ne) laser in the prevention and treatment of radiation induced mucositis in head and neck cancer patients. The patients with carcinoma of oral cavity with stages II-IV a being uniformly treated with curative total tumour dose of 66 Gy in 33 fractions over 6 wk were selected for the study. The patients were divided based on computer generated randamosization into laser (study group) and control groups with 25 patients in each group. Both study and control groups were comparable in terms of site of the lesion, stage of the cancer and histology. The study group patients were treated with He-Ne laser (wavelength 632.8 nm and output of 10mW) and control group patients were given oral analgesics, local application of anaesthetics, 0.9 per cent saline and povidine wash during the course of radiotherapy. All patients tolerated the laser treatment without any adverse effect or reactions. The result showed a significant difference in pain and mucositis (Pmucositis grade were significantly lower (Plow-level He-Ne laser therapy during the radiotherapy treatment was found to be effective in preventing and treating the mucositis in head and neck cancer patients. Further studies need to be done on a larger sample to find the mechanism.

  6. Polarization of a Helium-Neon Laser.

    Science.gov (United States)

    Jones, Edwin R.

    1996-01-01

    Describes an experiment that involves measuring the intensity of laser light passed by a linear polarizer. Discusses polarization effects, orthogonal polarizations, instrumentation, and further experiments. (JRH)

  7. Helium-neon laser therapy in the treatment of hydroxyapatite orbital implant exposure: A superior option.

    Science.gov (United States)

    Xu, Qi-Hua; Zhao, Chen; Zhu, Jian-Gang; Chen, Mei-Juan; Liu, Qing-Huai

    2015-09-01

    The aim of the present study was to evaluate the efficacy of helium-neon laser therapy in the treatment of hydroxyapatite orbital implant exposure and compare the results with those of a combined drugs and surgery regimen. A total of 70 patients with hydroxyapatite orbital implant exposure in 70 eyes were randomly divided into two groups: Helium-neon laser therapy (group A) and drugs plus surgery (group B). Each group contained 35 patients. The healing rates and times of the conjunctival wound were recorded and compared following helium-neon laser treatment or the drugs plus surgery regimen. Changes in the hydroxyapatite orbital implant prior to and following helium-neon laser irradiation were analyzed. A similar animal study was conducted using 24 New Zealand white rabbits, which received orbital implants and were then received drug treatment or helium-neon therapy. In the human experiment, the rates for conjunctival wound healing were 97.14% in group A and 74.29% in group B, with a significant difference between the groups (χ2=5.71, Pneon laser therapy and 14.33±3.20 days of drugs plus surgery. A statistically significant difference was found between the groups (t=8.97, Pneon laser therapy and 31.25±4.21 days of drugs plus surgery. The difference between the groups was statistically significant (t=7.91, Pneon laser therapy significantly promoted vascularization of the hydroxyapatite orbital implant. These results, combined with pathological findings in animals, which showed that a helium-neon laser promoted vascularization and had anti-inflammatory effects, suggest that helium-neon laser irradiation is an effective method for treating hydroxyapatite orbital implant exposure, thereby avoiding secondary surgery.

  8. Helium-neon laser irradiation stimulates migration and proliferation in melanocytes and induces repigmentation in segmental-type vitiligo.

    Science.gov (United States)

    Yu, Hsin-Su; Wu, Chieh-Shan; Yu, Chia-Li; Kao, Ying-Hsien; Chiou, Min-Hsi

    2003-01-01

    Low-energy helium-neon lasers (632.8 nm) have been employed in a variety of clinical treatments including vitiligo management. Light-mediated reaction to low-energy laser irradiation is referred to as biostimulation rather than a thermal effect. This study sought to determine the theoretical basis and clinical evidence for the effectiveness of helium-neon lasers in treating vitiligo. Cultured keratinocytes and fibroblasts were irradiated with 0.5-1.5 J per cm2 helium-neon laser radiation. The effects of the helium-neon laser on melanocyte growth and proliferation were investigated. The results of this in vitro study revealed a significant increase in basic fibroblast growth factor release from both keratinocytes and fibroblasts and a significant increase in nerve growth factor release from keratinocytes. Medium from helium-neon laser irradiated keratinocytes stimulated [3H]thymidine uptake and proliferation of cultured melanocytes. Furthermore, melanocyte migration was enhanced either directly by helium-neon laser irradiation or indirectly by the medium derived from helium-neon laser treated keratinocytes. Thirty patients with segmental-type vitiligo on the head and/or neck were enrolled in this study. Helium-neon laser light was administered locally at 3.0 J per cm2 with point stimulation once or twice weekly. The percentage of repigmented area was used for clinical evaluation of effectiveness. After an average of 16 treatment sessions, initial repigmentation was noticed. Marked repigmentation (>50%) was observed in 60% of patients with successive treatments. Basic fibroblast growth factor is a putative melanocyte growth factor, whereas nerve growth factor is a paracrine factor for melanocyte survival in the skin. Both nerve growth factor and basic fibroblast growth factor stimulate melanocyte migration. It is reasonable to propose that helium-neon laser irradiation clearly stimulates melanocyte migration and proliferation and mitogen release for melanocyte growth

  9. Photobiological effects of helium neon laser on hematologic and biochemical factors of rabbit blood

    Directory of Open Access Journals (Sweden)

    J Rahmani Kahnamoei

    2008-11-01

    Full Text Available Low-level helium neon laser has many applications due to its photobiostimulatory effects. Although the therapeutic effects of low-level laser radiation of different wavelengths and doses are well known, but the exact mechanism of action of the laser radiation on living cells is not yet determined. The present study is designed to evaluate the photobiological effects of 2 mw helium neon laser with wavelength of 632.8 nm on hematologic and biochemical factors of rabbit blood for this purpose, 30 male New Zealand white rabbits with the body weight of 1/5-2 kg were randomly allocated into two groups of control and laser treatment. Animals of both groups were anesthetized and those of laser treatment group were subjected to irradiation with helium neon laser at a                        wavelength of 632.8 nm and output 2 mw for 30 minutes. Finally blood samples were collected from all animals and the biochemical and hematologic factors evaluated. Significant difference (p

  10. Effect of helium-neon laser auriculotherapy on experimental pain threshold.

    Science.gov (United States)

    King, C E; Clelland, J A; Knowles, C J; Jackson, J R

    1990-01-01

    This study was conducted to examine the effects of helium-neon laser auriculotherapy on experimental pain threshold. Eighty healthy female and male subjects, aged 18 to 39 years, were assigned randomly to one of two treatment groups. Subjects in the Experimental Group (n = 41) received laser stimulation, and subjects in the Control Group (n = 39) received sham stimulation to appropriate acupuncture points on the left ear. Experimental pain threshold at the ipsilateral wrist was determined with an electrical stimulus immediately before and after treatment. The mean change (posttreatment minus pretreatment) for the Experimental Group was greater than the mean change for the Control Group (p less than .05). The Experimental Group demonstrated a statistically significant (p less than .05) increase in mean pain threshold after treatment, but the Control Group did not. Results indicate that helium-neon laser auriculotherapy can increase experimental pain threshold and suggest a possible alternative for patients intolerant of transcutaneous electrical nerve stimulation.

  11. [Low-intensity helium-neon laser in the treatment of patients after endonasal dacryocystorhinostomy].

    Science.gov (United States)

    Beloglazov, V G; At'kova, E L; Nurieva, S M; Khvedelidze, E P

    2004-01-01

    Described in the paper is an efficiency study of using, postoperatively, the low-intensity helium-neon laser (LIHNL) in patients with obstruction of the lacrimal tracts. Eighty patients were examined after endonasal dacryocystorhinostomy. They were shared between 2 groups with respect to a postoperative course: group 1--experimental, 40 patients, and group 2--control, 40 patients. The experimental patients received, apart from the traditional postoperative therapy, a course of LIHNL therapy. The controls received only the traditional postoperative treatment. The efficiency of postoperative treatment was evaluated by clinical, instrumental and laboratory examination methods. The study denoted that the use of LIHNL in the early postoperative period after endonasal dacryocystorhinostomy had a pronounced anti-inflammatory effect, speeded up the wound healing, prevented the growth of granulation tissues and the merging of the shaped lacrimal-sac fistula with the nasal cavity. LIHNL contributed to a complete recovery of the functional activity of the nasal mucous tunic. Thus, the LIHNL therapy essentially facilitates the postoperative management of patients, cuts the rehabilitation period and enhances the treatment results.

  12. Biostimulation of wound healing in vivo by a helium-neon laser.

    Science.gov (United States)

    Lyons, R F; Abergel, R P; White, R A; Dwyer, R M; Castel, J C; Uitto, J

    1987-01-01

    Clinical observations have suggested that low-energy lasers might stimulate wound healing. To understand the mechanism of the biostimulation, we previously examined the effects of low-energy lasers on collagen production by human skin fibroblasts and reported an increase of collagen synthesis in vitro. To examine the effects of low-energy lasers in vivo, hairless mice were experimentally wounded, sutured, and subjected to laser irradiation by a helium-neon laser with a power output of 1.56 mW and an energy fluence of 1.22 Joules/cm2. Experimental wounds were subjected to laser treatment every other day for 2 months; control wounds remained untreated. Specimens from the wounds were then examined for histological findings, tensile strength, and total collagen content. Results demonstrated a considerable improvement in the tensile strength of the laser-irradiated wounds at 1 and 2 weeks. Furthermore, the total collagen content was significantly increased at 2 months when compared with control wounds. These results suggest a beneficial effect of the helium-neon laser on wound healing in vivo.

  13. Helium-neon laser improves bone repair in rabbits: comparison at two anatomic sites.

    Science.gov (United States)

    Peccin, Maria Stella; de Oliveira, Flavia; Muniz Renno, Ana Claudia; Pacheco de Jesus, Gustavo Protasio; Pozzi, Renan; Gomes de Moura, Carolina Foot; Giusti, Paulo Ricardo; Ribeiro, Daniel Araki

    2013-07-01

    The purpose of this study was to evaluate the influence of helium-neon laser on bone repair of femur and tibia in rabbits. For this purpose, 15 New Zealand rabbits underwent bilateral bone damage (tibia and femur) using a spherical bur. Helium-neon laser light, at a fluency of 6 J∕cm(2) and wavelength of 632.8 nm was applied on the left legs (laser group). The right tibia or femur lesions (control group) served as negative control. All sections were histopathologically analyzed using HE sections and the morphometric data from bone tissue and hyaline cartilage were achieved. Histopathological analysis showed regular bone trabeculae covered by osteoblastic cells after 1 week in the group exposed to laser therapy from femur and tibia indistinctly. After 3 weeks, the laser group showed new bone formation coming from the bony walls in the femur and tibia as well. On the 5th week, well-defined trabecula undergoing remodeling process was detected for the most intense pattern in tibia only. Morphometric analysis revealed significant statistical differences (p neon laser is able to improve bone repair in rabbits being the most pronounced effect in tibia.

  14. Safe Helium--Neon Lasers Advance Understanding of Light

    Science.gov (United States)

    Knowles, C. Harry

    1972-01-01

    Experimental data, Federal and State regulations, and user data are presented to assess the safety factors of low-power lasers. General safety precautions, basic laser theory, the place of the laser in the classroom, and some introductory exercises are also presented. (Author/TS)

  15. Helium Neon laser therapy for post mastectomy lymphedema and ...

    African Journals Online (AJOL)

    Mohamed M. Khalaf

    2012-12-08

    Dec 8, 2012 ... therapy and decongestive lymphatic therapy. Group B received placebo laser therapy in addition to decongestive lymphatic therapy. Measurements of limb volume and shoulder mobility (by tape measurement and standard goniometer) were collected before treatment and after six months of treatment.

  16. Photobiomodulation by helium neon and diode lasers in an excisional wound model: A single blinded trial

    Directory of Open Access Journals (Sweden)

    Snehil Dixit

    2012-01-01

    Full Text Available Background: Application of different kinds of lasers in clinical and experimental studies causes photobiomodulation that works at localized cellular and humoral level on various biological systems. Increased numbers of fibroblasts, myofibroblast, and degranulation of mast cells have been the observed benefits post-irradiation. Objective: Was to find out the effect of irradiation with energy densities of 3.38 J/cm 2 , 8 J/cm 2 , and 18 J/cm 2 on animal tissue (albino wistar rats in an excisional wound model and to assess changes in biochemical (hydroxyproline and histopathological levels in excisional wound model. Materials and Methods: The animals were divided into 4 groups, which were labeled as L1, diode laser (18 J/cm 2 , L2 Helium-neon (He-Ne, 8 J/cm 2 , L3 diode laser (3.38 J/cm 2 , and sham treatment for control was depicted by C, respectively. Histological and hydroxyproline analysis was performed on 7, 14, 21 days of post-wounding. One-way analysis of variance, ANOVA and Bonferroni′s multiple comparison tests were done for tissue hydroxyproline levels. Results: There was no significant increase in the hydroxyproline content (P < 0.005 when observed in study group and compared to controls. Whereas significant epithelizations was seen in group treated with He-Ne laser of intensity of 8 J/cm 2 . Conclusion: The experimental observations suggest that low intensity helium-neon laser of 8 J/cm 2 intensity facilitated photo stimulation by tissue repair, but failed to show significant tissue hydroxyproline levels in excisional wound model.

  17. Helium-neon laser irradiation stimulates cell proliferation through photostimulatory effects in mitochondria.

    Science.gov (United States)

    Hu, Wan-Ping; Wang, Jeh-Jeng; Yu, Chia-Li; Lan, Cheng-Che E; Chen, Gow-Shing; Yu, Hsin-Su

    2007-08-01

    Previous reports have shown that cellular functions could be influenced by visual light (400-700 nm). Recent evidence indicates that cellular proliferation could be triggered by the interaction of a helium-neon laser (He-Ne laser, 632.8 nm) with the mitochondrial photoacceptor-cytochrome c oxidase. Our previous studies demonstrated that He-Ne irradiation induced an increase in cell proliferation, but not migration, in the melanoma cell line A2058 cell. The aim of this study was to investigate the underlying mechanisms involved in photostimulatory effects induced by an He-Ne laser. Using the A2058 cell as a model for cell proliferation, the photobiologic effects induced by an He-Ne laser were studied. He-Ne irradiation immediately induced an increase in mitochondrial membrane potential (delta psi(mt)), ATP, and cAMP via enhanced cytochrome c oxidase activity and promoted phosphorylation of Jun N-terminal kinase (JNK)/activator protein-1 (AP-1) expressions. He-Ne irradiation-induced A2058 cell proliferation was significantly abrogated by the addition of delta psi(mt) and JNK inhibitors. Moreover, treatment with an He-Ne laser resulted in delayed effects on IL-8 and transforming growth factor-beta1 release from A2058 cells. These results suggest that He-Ne irradiation elicits photostimulatory effects in mitochondria processes, which involve JNK/AP-1 activation and enhanced growth factor release, and ultimately lead to A2058 cell proliferation.

  18. Photobiomodulation by helium neon and diode lasers in an excisional wound model: A single blinded trial.

    Science.gov (United States)

    Dixit, Snehil; Maiya, Arun; Rao, Laxmi; Rao, M Arjun; Shastry, Barkur Ananthakrishna; Ramachandra, L

    2012-01-01

    Application of different kinds of lasers in clinical and experimental studies causes photobiomodulation that works at localized cellular and humoral level on various biological systems. Increased numbers of fibroblasts, myofibroblast, and degranulation of mast cells have been the observed benefits post-irradiation. Was to find out the effect of irradiation with energy densities of 3.38 J/cm(2), 8 J/cm(2), and 18 J/cm(2) on animal tissue (albino wistar rats) in an excisional wound model and to assess changes in biochemical (hydroxyproline) and histopathological levels in excisional wound model. The animals were divided into 4 groups, which were labeled as L1, diode laser (18 J/cm(2)), L2 Helium-neon (He-Ne, 8 J/cm(2)), L3 diode laser (3.38 J/cm(2)), and sham treatment for control was depicted by C, respectively. Histological and hydroxyproline analysis was performed on 7, 14, 21 days of post-wounding. One-way analysis of variance, ANOVA and Bonferroni's multiple comparison tests were done for tissue hydroxyproline levels. There was no significant increase in the hydroxyproline content (P neon laser of 8 J/cm(2) intensity facilitated photo stimulation by tissue repair, but failed to show significant tissue hydroxyproline levels in excisional wound model.

  19. The effect of low-level helium-neon laser on oral wound healing

    Science.gov (United States)

    Sardari, Farimah; Ahrari, Farzaneh

    2016-01-01

    Background: The effectiveness of low power lasers on incisional wound healing, because of conflicting results of previous studies, is uncertain. Therefore, the aim of this study was to evaluate the effects of low-level helium-neon (He-Ne) laser irradiation on wound healing in rat's oral mucosa. Materials and Methods: Sixty-four standardized incisions were carried out on the buccal mucosa of 32 male Wistar divided into four groups of eight animals each. Each rat received two incisions on the opposite sides of the buccal mucosa by a steel scalpel. On the right side (test side), a He-Ne laser (632 nm) was employed on the incision for 40 s. Laser radiation was used just in 1st day, 1st and 2nd day, 1st and 3rd day, and continuous 3 days in groups of A, B, C, and D of rats, respectively. The left side (control side) did not receive any laser. Histological processing and hematoxylin and eosin staining were done on tissue samples after 5 days. Wilcoxon and Kruskal-Wallis tests were used for statistical analysis. Results: Histological analysis showed that the tissue healing after continuous 3 days on the laser irradiated side was better than the control side, but there was no difference between the two sides in each groups (P > 0.05). Conclusion: This study showed that He-Ne laser had no beneficial effects on incisional oral wound healing particularly in 5 days after laser therapy. Future research in the field of laser effects on oral wound healing in human is recommended. PMID:26962312

  20. Helium-neon laser in viability of random skin flap in rats.

    Science.gov (United States)

    Pinfildi, Carlos E; Liebano, Richard E; Hochman, Bernardo S; Ferreira, Lydia M

    2005-07-01

    The purpose of this study was to determine the role of helium-neon (He-Ne) laser random skin flap viability in rats. Experimentally controlled randomized study. Forty-eight Wistar-EPM rats were used, weighed, and divided into 4 groups with 12 rats each. The random skin flap was performed measuring 10 x 4 cm, with a plastic sheet interposed between the flap and the donor site. The Group 1 (control) underwent sham irradiation with He-Ne laser. The Group 2 was submitted to laser irradiation, using the punctual contact technique on the skin flap surface. The Group 3 was submitted to laser irradiation surrounding the skin flap, and the Group 4 was submitted to laser irradiation both on the skin flap surface and around it. The experimental groups were submitted to He-Ne laser irradiation with 3 J/cm(2) energy density immediately after the surgery and for the four subsequent days. The percentage of necrotic area of the four groups was calculated at the 7th post-operative day, through a paper-template method. Group 1 reached an average necrotic area of 48.86%; Group 2, 38.67%; Group 3, 35.34%; and Group 4, 22.61%. After the statistic analysis, results showed that all experimental groups reached statistically significant values when compared to the control group, and Group 4 was the best one, when compared to all groups of this study (P<0.001). The He-Ne laser irradiation was efficient to increase random skin flap viability in rats. (c) 2005 Wiley-Liss, Inc.

  1. Effects of helium-neon laser on the mucopolysaccharide induction in experimental osteoarthritic cartilage.

    Science.gov (United States)

    Lin, Y-S; Huang, M-H; Chai, C-Y

    2006-04-01

    To investigate the effects of mucopolysaccharide induction after treatment by low power laser for experimental osteoarthritis (OA). Seventy-two rats with three different degrees of papain induced OA over right knee joints were collected for helium-neon (He-Ne) laser treatment. The severity of induced arthritis was measured by 99mTc bone scan and classified into three groups (I-III) by their radioactivity ratios (right to left knee joints). The rats in each group were further divided into study subgroups (Is, IIs, and IIIs) and control subgroups (Ic, IIc, and IIIc) randomly. The arthritic knees in study subgroups received He-Ne laser treatment, and those in controls received sham laser treatment. The changes of arthritic severity after treatment and follow-up 2 months later were measured. The histopathological changes were evaluated through light microscope after disarticulation of sections (H.E. stain), and the changes of mucopolysaccharide density in cartilage matrix were measured by Optimas scanner analyzer after Alcian blue (AB) stain. The densities of mucopolysaccharide induced after treatment in arthritic cartilage were compared and correlated with their histopathological changes. The density of mucopolysaccharide rose at the initial stage of induced arthritis, and decreased progressively in later stages. The densities of mucopolysaccharide in treated rats increased upon complete laser treatment more than those of the controls, which is closely related with the improvement in histopathological findings, but conversely with the changes in arthritic severity. He-Ne laser treatment will enhance the biosynthesis of arthritic cartilage, and results in the improvement of arthritic histopathological changes.

  2. Low level helium neon laser therapy for chemoradiotherapy induced oral mucositis in oral cancer patients - a randomized controlled trial.

    Science.gov (United States)

    Gautam, Ajay Prashad; Fernandes, Donald J; Vidyasagar, Mamidipudi S; Maiya, G Arun

    2012-09-01

    Patients receiving chemoradiotherapy (CRT) for oral cancer (OC) often develop oral mucositis (OM). OM associated pain severely affects oral functions and nutrition of the patient, resulting in narcotic analgesic use and CRT interruption. Laser therapy has shown some promising results in preventing and treating OM caused by cancer therapies. So in this trial we used prophylactic Low Level Helium Neon (He-Ne) Laser for the prevention and treatment of CRT induced OM in OC patients. This double blinded trial block randomized 121 primary OC patients scheduled to undergo CRT [RT dosage=66 Gray/33 fractions for 5 days/week and chemotherapy (3 weekly Cisplatin)] into laser (n=60) and placebo (n=61) group. Laser group received He-Ne Laser (λ=632.8 nm, P=24 mW, ED=3.5 J/cm(2)) while placebo received sham treatment just before radiation for 6.5 weeks. OM (RTOG/EORTC Scale), its associated pain, and total parenteral nutrition (TPN), were assessed on every week by a blinded assessor. Also opioid analgesic use, weight loss and any CRT break were recorded. Data was analyzed using descriptive statistics, t-test and Man Whitney U test. Level of significance was set at plaser than placebo group patients. Also duration of severe OM and pain experienced was less in laser than placebo group. CRT break required only for placebo group (9%) patients. Low Level He-Ne Laser decreased the incidence of CRT induced severe OM and its associated pain, opioid analgesics use and TPN. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Demonstration of elevated type I and type III procollagen mRNA levels in cutaneous wounds treated with helium-neon laser. Proposed mechanism for enhanced wound healing.

    Science.gov (United States)

    Saperia, D; Glassberg, E; Lyons, R F; Abergel, R P; Baneux, P; Castel, J C; Dwyer, R M; Uitto, J

    1986-08-14

    To assess laser modulation of wound healing, full-thickness cutaneous wounds were produced in the backs of pigs, and subjected to treatment with helium-neon laser. For comparison, some wounds were treated with non-laser energy source (a tungsten light) or left untreated as controls. Type I and type III procollagen mRNA levels were determined in the wounds by molecular hybridization with cDNA probes. The results indicated that type I and type III mRNA levels were markedly increased at days 17 and 28 of the healing in wounds treated with He-Ne laser, when compared to control or tungsten light-treated wounds. The results suggest that helium-neon laser stimulates wound healing by enhancing procollagen gene expression. These observations may have relevance to previous clinical studies suggesting that helium-neon laser stimulates wound healing.

  4. Effects of helium-neon laser on levels of stress protein and arthritic histopathology in experimental osteoarthritis.

    Science.gov (United States)

    Lin, Yueh-Shuang; Huang, Mao-Hsiung; Chai, Chee-Yin; Yang, Rei-Cheng

    2004-10-01

    To investigate the effect of low-power laser therapy on levels of stress proteins (SPs) in experimental arthritis and their relation to the bioeffects on arthritic cartilage repair. A total of 42 rats with similar degrees of induced arthritis evaluated by means of bone scan were divided randomly into two groups. In the treated group, 21 rats received helium-neon laser treatment; in the control group, 21 rats received sham laser treatment. The changes in chondrocytes of SPs were measured by electrophoresis of proteins extracted from chondrocytes of arthritic cartilage at various time periods. The histopathologic changes and the presence of SP of arthritic cartilage were identified by hematoxylin and eosin stain and by immunostains of SP72 antibody individually from frozen sections of arthritic cartilage. SP density increased markedly in rats after laser treatment and was closely related to the repair of arthritic cartilage. Furthermore, the pathohistology of arthritic cartilage improved significantly with the decline of SP levels in the follow-up period. Helium-neon (632 nm) low-power laser can enhance SP production in arthritic chondrocytes. The extragenic production of SP is well correlated with the therapeutic effect of low-power laser in preserving chondrocytes and the repair of arthritic cartilage in rats.

  5. Sensing earth's rotation with a helium-neon ring laser operating at 1.15  μm.

    Science.gov (United States)

    Ulrich Schreiber, K; Thirkettle, Robert J; Hurst, Robert B; Follman, David; Cole, Garrett D; Aspelmeyer, Markus; Wells, Jon-Paul R

    2015-04-15

    We report on the operation of a 2.56  m2 helium-neon based ring laser interferometer at a wavelength of 1.152276 μm using crystalline coated intracavity supermirrors. This work represents the first implementation of crystalline coatings in an active laser system and expands the core application area of these low-thermal-noise cavity end mirrors to inertial sensing systems. Stable gyroscopic behavior can only be obtained with the addition of helium to the gain medium as this quenches the 1.152502 μm (2s4→2p7) transition of the neon doublet which otherwise gives rise to mode competition. For the first time at this wavelength, the ring laser is observed to readily unlock on the bias provided by the earth's rotation alone, yielding a Sagnac frequency of approximately 59 Hz.

  6. Effect of helium/neon laser irradiation on nerve growth factor synthesis and secretion in skeletal muscle cultures.

    Science.gov (United States)

    Schwartz, Fidi; Brodie, Chaya; Appel, Elana; Kazimirsky, Gila; Shainberg, Asher

    2002-04-01

    Low energy laser irradiation therapy in medicine is widespread but the mechanisms are not fully understood. The aim of the present study was to elucidate the mechanism by which the light might induce therapeutic effects. Skeletal muscle cultures were chosen as a target for light irradiation and nerve growth factor (NGF) was the biochemical marker for analysis. It was found that there is a transient elevation of intracellular calcium in the myotubes immediately after irradiation (Pneon irradiation (633 nm) with an energy of 3 J/cm(2). In addition, helium/neon irradiation augmented the level of NGF mRNA fivefold and increased NGF release to the medium of the myotubes. Thus, it is speculated that transient changes in calcium caused by light can modulate NGF release from the myotubes and also affect the nerves innervating the muscle. The NGF is probably responsible for the beneficial effects of low-level light.

  7. [Efficiency of a combination of haloaerosols and helium-neon laser in the multimodality treatment of patients with bronchial asthma].

    Science.gov (United States)

    Faradzheva, N A

    2007-01-01

    A hundred and thirty-eight patients with infection-dependent bronchial asthma, including 73 with moderate persistent asthma and 65 with severe persistent one, were examined. Four modes of a combination of traditional (drug) therapy (DT) and untraditional (halotherapy (HT) and endobronchial helium-neon laser irradiation (ELI) one were used. The efficiency of the treatment performed was evaluated, by determining the time course of clinical symptoms of the disease on the basis of scores of their magnitude and the patients' condition. The findings indicated that in moderate persistent asthma, both HT and ELI in combination with DT exerted an equal therapeutic effect, which provided a good and excellent condition in 83.3% of cases. In severe persistent asthma, such a condition was achieved in 93.75% of cases only when multimodality treatment involving DT, HT, and ELI had been performed.

  8. High-power helium-neon laser irradiation inhibits the growth of traumatic scars in vitro and in vivo.

    Science.gov (United States)

    Shu, Bin; Ni, Guo-Xin; Zhang, Lian-Yang; Li, Xiang-Ping; Jiang, Wan-Ling; Zhang, Li-Qun

    2013-05-01

    This study explored the inhibitory effect of the high-power helium-neon (He-Ne) laser on the growth of scars post trauma. For the in vitro study, human wound fibroblasts were exposed to the high-power He-Ne laser for 30 min, once per day with different power densities (10, 50, 100, and 150 mW/cm(2)). After 3 days of repeated irradiation with the He-Ne laser, fibroblast proliferation and collagen synthesis were evaluated. For in vivo evaluation, a wounded animal model of hypertrophic scar formation was established. At postoperative day 21, the high-power He-Ne laser irradiation (output power 120 mW, 6 mm in diameter, 30 min each session, every other day) was performed on 20 scars. At postoperative day 35, the hydroxyproline content, apoptosis rate, PCNA protein expression and FADD mRNA level were assessed. The in vitro study showed that the irradiation group that received the power densities of 100 and 150 mW/cm(2) showed decreases in the cell proliferation index, increases in the percentage of cells in the G0/G1 phase, and decreases in collagen synthesis and type I procollagen gene expression. In the in vivo animal studies, regions exposed to He-Ne irradiation showed a significant decrease in scar thickness as well as decreases in hydroxyproline levels and PCNA protein expression. Results from the in vitro and in vivo studies suggest that repeated irradiation with a He-Ne laser at certain power densities inhibits fibroblast proliferation and collagen synthesis, thereby inhibits the growth of hypertrophic scars.

  9. Direction sensitive laser velocimeter. [determining the direction of particles using a helium-neon laser

    Science.gov (United States)

    Franke, J. M. (Inventor)

    1981-01-01

    A laser velocimeter is described which determines the direction of movement of particles. A laser produces a transmitted beam that illuminates the volume under investigation. The backscattered light is divided into two equal intensity beams. A first part of a sample of the transmitted beam is mixed with one of the two equal intensity beams and applied to a first photodetector. A second part of the sample is phase shifted by 90 deg, mixed with the other of the two equal intensity beams and applied to a second photodetector. The output of the first photodetector is phase shifted by 90 deg and then multiplied with the output of the second photodetector to produce a signal indicative of direction of movement.

  10. Helium-neon laser irradiation of cryopreserved ram sperm enhances cytochrome c oxidase activity and ATP levels improving semen quality.

    Science.gov (United States)

    Iaffaldano, N; Paventi, G; Pizzuto, R; Di Iorio, M; Bailey, J L; Manchisi, A; Passarella, S

    2016-08-01

    This study examines whether and how helium-neon laser irradiation (at fluences of 3.96-9 J/cm(2)) of cryopreserved ram sperm helps improve semen quality. Pools (n = 7) of cryopreserved ram sperm were divided into four aliquots and subjected to the treatments: no irradiation (control) or irradiation with three different energy doses. After treatment, the thawed sperm samples were compared in terms of viability, mass and progressive sperm motility, osmotic resistance, as well as DNA and acrosome integrity. In response to irradiation at 6.12 J/cm(2), mass sperm motility, progressive motility and viability increased (P < 0.05), with no significant changes observed in the other investigated properties. In parallel, an increase (P < 0.05) in ATP content was detected in the 6.12 J/cm(2)-irradiated semen samples. Because mitochondria are the main cell photoreceptors with a major role played by cytochrome c oxidase (COX), the COX reaction was monitored using cytochrome c as a substrate in both control and irradiated samples. Laser treatment resulted in a general increase in COX affinity for its substrate as well as an increase in COX activity (Vmax values), the highest activity obtained for sperm samples irradiated at 6.12 J/cm(2) (P < 0.05). Interestingly, in these irradiated sperm samples, COX activity and ATP contents were positively correlated, and, more importantly, they also showed positive correlation with motility, suggesting that the improved sperm quality observed was related to mitochondria-laser light interactions. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Effectiveness of helium-neon laser irradiation on viability and cytotoxicity of diabetic-wounded fibroblast cells.

    Science.gov (United States)

    Houreld, N N; Abrahamse, H

    2007-12-01

    This study investigated the effectiveness of helium-neon (He-Ne) laser irradiation at increasing intervals on diabetic-induced wounded human skin fibroblast cells (WS1) at a morphological, cellular, and molecular level. The controversies over light therapy can be explained by the differing exposure regimens and models used. No therapeutic window for dosimetry and mechanism of action has been determined at the level of individual cell types, particularly in diabetic cells in vitro. WS1 cells were used to simulate an in vitro wounded diabetic model. The effect of the frequency of He-Ne irradiation (632.8 nm) at a fluence of 5 J/cm(2) was determined by analysis of cell morphology, viability, cytotoxicity, and DNA damage. Cells were irradiated using three different protocols: they were irradiated at 30 min only; irradiated twice, at 30 min and at 24 h; or irradiated twice, at 30 min and at 72 h post-wound induction. A single exposure to 5 J/cm(2) 30 min post-wound induction increased cellular damage. Irradiation of cells at 30 min and at 24 h post-wound induction decreased cellular viability, cytotoxicity, and DNA damage. However, complete wound closure as well as an increase in viability and a decrease in cytotoxicity and DNA damage occurs when cells were irradiated at 30 min and at 72 h post-wound induction. Wounded diabetic WS1 cells irradiated to 5 J/cm(2) showed increased cellular repair when irradiated with adequate time between irradiations, allowing time for cellular response mechanisms to take effect. Therefore, the irradiation interval was shown to play an important role in wound healing in vitro and should be taken into account.

  12. The effect of low-level helium-neon laser on oral wound healing

    Directory of Open Access Journals (Sweden)

    Farimah Sardari

    2016-01-01

    Conclusion: This study showed that He-Ne laser had no beneficial effects on incisional oral wound healing particularly in 5 days after laser therapy. Future research in the field of laser effects on oral wound healing in human is recommended.

  13. Helium-neon and nitrogen laser irradiation accelerates the phagocytic activity of human monocytes.

    Science.gov (United States)

    Hemvani, Nanda; Chitnis, Dhananjay Sadashiv; Bhagwanani, Nijram Satramdas

    2005-12-01

    Intracellular survival of mycobacteria within monocytes is a crucial stage in the pathogenesis of tuberculosis. The aim was to check intracellular survival of Mycobacterium fortuitum within the human monocytes exposed to He-Ne and nitrogen laser irradiation. Tuberculosis remains one of the most important infectious diseases for developing countries. Low-level laser therapy (LLLT) has been tried to treat tubercular cavitory lung disease with encouraging results. The in vitro photobiological effect of low level laser radiation on the intracellular mycobacteria needs to be evaluated before we could go for large clinical trials. The aliquots of human monocytes from peripheral blood of healthy volunteers and tuberculosis cases were exposed to He-Ne or nitrogen laser beam. The non-irradiated monocytes from the same source served as controls. The monocytes were then challenged with M. fortuitum, and surviving mycobacteria within monocytes were subjected to viable counts. Enhanced killing of mycobacterial cells was seen among monocytes exposed to He-Ne and nitrogen laser irradiation. He-Ne and nitrogen laser irradiation activates the monocytes to increase intracellular killing of mycobacteria.

  14. Increased Wound-Healing Rate In Pig Skin Treated By Helium-Neon Laser.

    Science.gov (United States)

    Abergel, R. Patrick; Glassberg, Edward; Uitto, Jouni

    1988-06-01

    We have demonstrated that 11cNc, laws stimulate collagen synthesis both in human stun fibroblast cultures and hairless mice in vivo. Subscqucnt studies on pig skin have also idcntificd the mechanism of the collagen stimulation. Both type 1 and typc 111 procolagcn mRNA, levels were markcdly elevated at day 17 and 26 in wounds treated by laser. Furthermore, typo ill procollagen was cicvatcd in carly stages of wound healing, at day 10, confirming the notion that typc 111 collagen accumulation precedes that of typc 1 in wound healing processes. (for summary,please see table and references below)

  15. Low-energy helium-neon laser induces locomotion of the immature melanoblasts and promotes melanogenesis of the more differentiated melanoblasts: recapitulation of vitiligo repigmentation in vitro.

    Science.gov (United States)

    Lan, Cheng-Che E; Wu, Ching-Shuang; Chiou, Min-Hsi; Hsieh, Pei-Chen; Yu, Hsin-Su

    2006-09-01

    Helium-neon laser (He-Ne Laser, 632.8 nm) is a low-energy laser that has therapeutic efficacy on various clinical conditions. Our previous study has demonstrated efficacy of He-Ne laser on vitiligo, a disease characterized by skin depigmentation. To regain skin tone on vitiligo lesions, the process began by the migration of the immature melanoblasts (MBs) to the epidermis, which was followed by their functional development to produce melanin. In this study, we investigated the physiologic effects of He-Ne laser irradiation on two MB cell lines: the immature NCCmelb4 and the more differentiated NCCmelan5. The intricate interactions between MBs with their innate extracelluar matrix, fibronectin, were also addressed. Our results showed that He-Ne laser irradiation enhanced NCCmelb4 mobility via enhanced phosphorylated focal adhesion kinase expression and promoted melanogenesis in NCCmelan5. In addition, He-Ne laser decreased the affinity between NCCmelb4 and fibronectin, whereas the attachment of NCCmelan5 to fibronectin increased. The alpha5beta1 integrin expression on NCCmelb4 cells was enhanced by He-Ne laser. In conclusion, we have demonstrated that He-Ne laser induced different physiologic changes on MBs at different maturation stages and recapitulated the early events during vitiligo repigmentation process brought upon by He-Ne laser in vitro.

  16. The role of laser fluence in cell viability, proliferation, and membrane integrity of wounded human skin fibroblasts following helium-neon laser irradiation.

    Science.gov (United States)

    Hawkins, Denise H; Abrahamse, Heidi

    2006-01-01

    In medicine, lasers have been used predominantly for applications, which are broadly termed low level laser therapy (LLLT), phototherapy or photobiomodulation. This study aimed to establish cellular responses to Helium-Neon (632.8 nm) laser irradiation using different laser fluences (0.5, 2.5, 5, 10, and 16 J/cm(2)) with a single exposure on 2 consecutive days on normal and wounded human skin fibroblasts. Changes in normal and wounded fibroblast cell morphology were evaluated by light microscopy. Changes following laser irradiation were evaluated by assessing the mitochondrial activity using adenosine triphosphate (ATP) luminescence, cell proliferation using neutral red and an alkaline phosphatase (ALP) activity assay, membrane integrity using lactate dehydrogenase (LDH), and percentage cytotoxicity and DNA damage using the Comet assay. Morphologically, wounded cells exposed to 5 J/cm(2) migrate rapidly across the wound margin indicating a stimulatory or positive influence of phototherapy. A dose of 5 J/cm(2) has a stimulatory influence on wounded fibroblasts with an increase in cell proliferation and cell viability without adversely increasing the amount of cellular and molecular damage. Higher doses (10 and 16 J/cm(2)) were characterized by a decrease in cell viability and cell proliferation with a significant amount of damage to the cell membrane and DNA. Results show that 5 J/cm(2) stimulates mitochondrial activity, which leads to normalization of cell function and ultimately stimulates cell proliferation and migration of wounded fibroblasts to accelerate wound closure. Laser irradiation can modify cellular processes in a dose or fluence (J/cm(2)) dependent manner.

  17. Helium-Neon Laser Irradiation Promotes the Proliferation and Migration of Human Epidermal Stem Cells In Vitro: Proposed Mechanism for Enhanced Wound Re-epithelialization

    Science.gov (United States)

    Liao, Xuan; Xie, Guang-Hui; Cheng, Biao; Li, Sheng-Hong; Xie, Shan; Xiao, Li-Ling; Fu, Xiao-Bing

    2014-01-01

    Abstract Objective: The present study was conducted to investigate the effects of helium-neon (He-Ne) laser irradiation on the proliferation, migration, and differentiation of cultured human epidermal stem cells (ESCs). Background data: A He-Ne laser with a wavelength of 632.8 nm is known to have photobiological effects, and is widely used for accelerating wound healing; however, the cellular mechanisms involved have not been completely understood. Methods: The ESCs were prepared from human foreskin, and irradiated by using He-Ne laser at 632.8 nm with 2 J/cm2. The ESC proliferation, migration, and differentiation were examined by using XTT assay, scratch assay, and flow cytometry technology, respectively. The phosphorylation of extracellular signal-regulated kinases (ERK) was analyzed by using Western blotting. Results: He-Ne laser irradiation markedly promoted cell proliferation and migration accompanied by an increase in the phosphorylation of ERK, but did not significantly influence cell differentiation. Conclusion: Our data indicated that photostimulation with a He-Ne laser resulted in a significant increase in human ESC proliferation and migration in vitro, which might contribute, at least partially, to accelerated wound re-epithelialization by low-level laser therapy. PMID:24661127

  18. Helium-neon laser irradiation promotes the proliferation and migration of human epidermal stem cells in vitro: proposed mechanism for enhanced wound re-epithelialization.

    Science.gov (United States)

    Liao, Xuan; Xie, Guang-Hui; Liu, Hong-Wei; Cheng, Biao; Li, Sheng-Hong; Xie, Shan; Xiao, Li-Ling; Fu, Xiao-Bing

    2014-04-01

    The present study was conducted to investigate the effects of helium-neon (He-Ne) laser irradiation on the proliferation, migration, and differentiation of cultured human epidermal stem cells (ESCs). A He-Ne laser with a wavelength of 632.8 nm is known to have photobiological effects, and is widely used for accelerating wound healing; however, the cellular mechanisms involved have not been completely understood. The ESCs were prepared from human foreskin, and irradiated by using He-Ne laser at 632.8 nm with 2 J/cm(2). The ESC proliferation, migration, and differentiation were examined by using XTT assay, scratch assay, and flow cytometry technology, respectively. The phosphorylation of extracellular signal-regulated kinases (ERK) was analyzed by using Western blotting. He-Ne laser irradiation markedly promoted cell proliferation and migration accompanied by an increase in the phosphorylation of ERK, but did not significantly influence cell differentiation. Our data indicated that photostimulation with a He-Ne laser resulted in a significant increase in human ESC proliferation and migration in vitro, which might contribute, at least partially, to accelerated wound re-epithelialization by low-level laser therapy.

  19. Induction of primitive pigment cell differentiation by visible light (helium-neon laser): a photoacceptor-specific response not replicable by UVB irradiation.

    Science.gov (United States)

    Lan, Cheng-Che E; Wu, Shi-Bei; Wu, Ching-Shuang; Shen, Yi-Chun; Chiang, Tzu-Ying; Wei, Yau-Huei; Yu, Hsin-Su

    2012-03-01

    Solar lights encompass ultraviolet (UV), visible, and infrared spectrum. Most previous studies focused on the harmful UV effects, and the biologic effects of lights at other spectrums remained unclear. Recently, lights at visible region have been used for regenerative purposes. Using the process of vitiligo repigmentation as a research model, we focused on elucidating the pro-differentiation effects induced by visible light. We first showed that helium-neon (He-Ne) laser (632.8 nm) irradiation stimulated differentiation of primitive pigment cells, an effect not replicable by UVB treatment even at high and damaging doses. In addition, significant increases of mitochondrial DNA copy number and the regulatory genes for mitochondrial biogenesis were induced by He-Ne laser irradiation. Mechanistically, we demonstrated that He-Ne laser initiated mitochondrial retrograde signaling via a Ca(2+)-dependent cascade. The impact on cytochrome c oxidase within the mitochondria is responsible for the efficacy of He-Ne laser in promoting melanoblast differentiation. Taken together, we propose that visible lights from the sun provide important environmental cues for the relatively quiescent stem or primitive cells to differentiate. In addition, our results also indicate that visible light may be used for regenerative medical purposes involving stem cells.

  20. Low-energy helium-neon laser induces melanocyte proliferation via interaction with type IV collagen: visible light as a therapeutic option for vitiligo.

    Science.gov (United States)

    Lan, C-C E; Wu, C-S; Chiou, M-H; Chiang, T-Y; Yu, H-S

    2009-08-01

    The treatment of vitiligo remains a challenge for clinical dermatologists. We have previously shown that the helium-neon laser (He-Ne laser, 632.8 nm) is a therapeutic option for treatment of this depigmentary disorder. Addressing the intricate interactions between melanocytes, the most important cellular component in the repigmentation scheme of vitiligo, and their innate extracellular matrix collagen type IV, the current study aimed to elucidate the effects of the He-Ne laser on melanocytes. Cultured melanocytes were irradiated with the He-Ne laser. Relevant biological parameters including cell attachment, locomotion and growth were evaluated. In addition, the potentially involved molecular pathways were also determined. Our results show that in addition to suppressing mobility but increasing attachment to type IV collagen, the He-Ne laser stimulates melanocyte proliferation through enhanced alpha2beta1 integrin expression. The expression of phosphorylated cyclic-AMP response element binding protein (CREB), an important regulator of melanocyte growth, was also upregulated by He-Ne laser treatment. Using a specific mitochondrial uncoupling agent [carbonyl cyanide m-chlorophenyl-hydrazone (CCCP)], the proliferative effect of the He-Ne laser on melanocytes was abolished and suppression of melanocyte growth was noted. In summary, we have demonstrated that the He-Ne laser imparts a growth stimulatory effect on functional melanocytes via mitochondria-related pathways and proposed that other minor pathways including DNA damage may also be inflicted by laser treatment on irradiated cells. More importantly, we have completed the repigmentation scheme of vitiligo brought about by He-Ne laser light in vitro and provided a solid theoretical basis regarding how the He-Ne laser induces recovery of vitiligo in vivo.

  1. Evaluation effect of low level Helium-Neon laser and Iranian propolis extract on Collagen Type I gene expression by human gingival fibroblasts: anin vitrostudy.

    Science.gov (United States)

    Eslami, Hosein; Motahari, Paria; Safari, Ebrahim; Seyyedi, Maryam

    2017-06-30

    production of collagen by fibroblast cells is a key component in wound healing. Several studies have shown that low level laser therapy (LLLT) and propolis extract stimulate collagen Type I production. The aim of this study is to evaluation the combined effect of LLL helium neon (632.8 nm) and Iranian propolis extract on collagen Type I gene expression by human gingival fibroblasts (HGF3-PI 53). Human gingival fibroblasts after culturing divided into six experimental groups: G1-control group, which received no irradiation and propolis extract, G2-irradiated at1.5 J/cm 2 , G3-irradiated at 0.15 J/cm 2 , G4-recived extract of propolis, G5- combined extract of propolis and 1.5 J/cm 2 laser irradiation and G6- combined extract of propolis and 0.15 J/cm 2 laser irradiation. The experiments were conducted in triplicate. After 24 hour, the total RNA was extracted and cDNA synthesis was performed. Type I collagen mRNA expression was determined with real time PCR. The obtained results illustrated a statistically significant difference between G3 (0.15 J/cm 2 ) and G1 (control group) in levels of collagen Type I messenger RNA (mRNA) expression (pType I gene. Expression of this gene decreases in other groups that this difference was statistically significant. LLLT in different dosage and propolis extract may result in decreased or increased collagen type I gene expression. However this effect should be investigated in clinical studies.

  2. Low-Energy Helium-Neon Laser Therapy Induces Repigmentation and Improves the Abnormalities of Cutaneous Microcirculation in Segmental-Type Vitiligo Lesions

    Directory of Open Access Journals (Sweden)

    Chieh-Shan Wu

    2008-04-01

    Full Text Available Segmental vitiligo (SV is a special form of vitiligo occurring in a dermatomal distribution, and an abnormality involving the sympathetic nerves supplying the affected dermatome is known to underlie this disorder. Previously, we have shown that SV is associated with an abnormal increase in cutaneous blood flow and adrenoceptor responses in the affected areas. Since SV is resistant to conventional forms of therapy, its management represents a challenge for dermatologists. Low energy helium-neon lasers (He-Ne laser, wavelength 632.8nm have been employed as a therapeutic instrument in many clinical situations, including vitiligo management and repair of nerve injury. The purpose of this study was to evaluate the effectiveness and safety of He-Ne lasers in treating SV, and determine their effects on the repair of sympathetic nerve dysfunction. Forty patients with stable-stage SV on the head and/or neck were enrolled in this study. He-Ne laser irradiation was administered locally at 3.0J/cm2 with point stimulation once or twice weekly. Cutaneous microcirculatory assessments in six SV patients were performed using a laser Doppler flowmeter. The sympathetic adrenoceptor response of cutaneous microcirculation was determined by measuring cutaneous blood flow before, during and after iontophoresis with sympathomimetic drugs (phenylephrine, clonidine and propranolol. All measurements of microcirculation obtained at SV lesions were simultaneously compared with contralateral normal skin, both before and after He-Ne laser treatment. After an average of 17 treatment sessions, initial repigmentation was noticed in the majority of patients. Marked repigmentation (> 50% was observed in 60% of patients with successive treatments. Cutaneous blood flow was significantly higher at SV lesions compared with contralateral skin, but this was normalized after He-Ne laser treatment. In addition, the abnormal decrease in cutaneous blood flow in response to clonidine was

  3. In vitro effects of helium-neon laser irradiation on human blood: blood viscosity and deformability of erythrocytes.

    Science.gov (United States)

    Mi, Xian-Qiang; Chen, Ji-Yao; Liang, Zi-Jun; Zhou, Lu-Wei

    2004-12-01

    The purpose of this study was to investigate the in vitro effects of He-Ne laser irradiation on some rheological factors of human blood, such as blood viscosity, erythrocyte deformability, and sedimentation rate. The intravascular irradiation of low power laser has been applied in pre-clinical and clinical to treat various pathological processes. However, the mechanism is not fully understood so far. Especially the interaction and related mechanism between the laser and blood are unclear. In this work, by measuring the change of the main rheological factors after laser irradiation, the interaction and mechanism were explored. A30-mW He-Ne laser was used for irradiation with a 4-5-mm-diameter beam spot on blood samples, with a fluence rate of about 150 mW/cm.(2) The irradiation time was 60 min, so the total dose of irradiation was 540 J/cm.(2) The pathological samples of blood were obtained from patients (volunteers), and each sample was divided into two tubes for irradiation and control. The blood viscosity, erythrocyte deformability, and sedimentation rate were measured after laser irradiation and compared with un-irradiated control. The blood samples with poor erythrocyte deformability were prepared by adding Ca(2+) to the normal erythrocytes of a healthy person for investigating the laser effect on erythrocyte deformability further. Laser irradiation reduced the erythrocyte sedimentation rate of blood samples, which had a hyper-sedimentation rate originally. The blood viscosity of samples in hyper-values was lowered by laser irradiation in all shear rates measured (10-110 S(-1)), with a relative variation of approximately 10%. The deformability of erythrocytes from pathological samples and Ca(2+)-treated samples was improved after laser irradiation. The positive effects of laser irradiation on improving the rheological properties of blood were demonstrated in vitro.

  4. Effect of low intensity helium-neon (HeNe) laser irradiation on experimental paracoccidioidomycotic wound healing dynamics.

    Science.gov (United States)

    Ferreira, Maria Carolina; Gameiro, Jacy; Nagib, Patrícia Resende Alo; Brito, Vânia Nieto; Vasconcellos, Elza da Costa Cruz; Verinaud, Liana

    2009-01-01

    The effect of HeNe laser on the extracellular matrix deposition, chemokine expression and angiogenesis in experimental paracoccidioidomycotic lesions was investigated. At days 7, 8 and 9 postinfection the wound of each animal was treated with a 632.8 nm HeNe laser at a dose of 3 J cm(-2). At day 10 postinfection, the wounds were examined by using histologic and immunohistochemical methods. Results revealed that laser-treated lesions were lesser extensive than untreated ones, and composed mainly by macrophages and lymphocytes. High IL-1beta expression was shown in the untreated group whereas in laser-treated animals the expression was scarce. On the other hand, the expression of CXCL-10 was found to be reduced in untreated animals and quite intensive and well distributed in the laser-treated ones. Also, untreated lesions presented vascular endothelial growth factor (VEGF) in a small area near the center of the lesion and high immunoreactivity for hypoxia-inducible factor-1 (HIF-1), whereas laser-treated lesions expressed VEGF surrounding blood vessels and little immunoreactivity for HIF-1. Laser-treated lesions presented much more reticular fibers and collagen deposition when compared with the untreated lesion. Our results show that laser was efficient in minimizing the local effects observed in paracoccidioidomycosis and can be an efficient tool in the treatment of this infection, accelerating the healing process.

  5. The influence of low-power helium-neon laser irradiation on function of selected peripheral blood cells.

    Science.gov (United States)

    Wasik, M; Gorska, E; Modzelewska, M; Nowicki, K; Jakubczak, B; Demkow, U

    2007-11-01

    The effects of low-level laser light irradiation are debatable and the mechanisms of its action are still unclear. This study was conducted to test the effects of low-level laser irradiation on human blood cells: erythrocytes, granulocytes, and lymphocytes. Whole blood obtained by phlebotomy was irradiated at 632.8 nm by using energy fluences 0.6 J/cm2. An analysis of blood gases revealed an increase in PO2 and SaO2 (Pirradiated blood. No shifts in PCO2 and pH were recorded. Spontaneous synthesis of DNA in T and B blood lymphocytes decreased significantly after laser irradiation (Pirradiated than in non-irradiated blood (Pirradiated blood increased in comparison with non-irradiated samples (Pirradiated samples were observed. These results reveal the influence of photodynamic reactions on the ability of blood to transport oxygen and on immunomodulatory effects on leukocytes.

  6. Effects of helium-neon laser irradiation and local anesthetics on potassium channels in pond snail neurons.

    Science.gov (United States)

    Ignatov, Yu D; Vislobokov, A I; Vlasov, T D; Kolpakova, M E; Mel'nikov, K N; Petrishchev, I N

    2005-10-01

    Intracellular dialysis and membrane voltage clamping were used to show that He-Ne laser irradiation of a pond snail neuron at a dose of 0.7 x 10(-4) J (power density 1.5 x 10(2) W/m2) increases the amplitude of the potential-dependent slow potassium current, while a dose of 0.7 x 10(-3) J decreases this current. Bupivacaine suppresses the potassium current. Combined application of laser irradiation at a dose of 0.7 x 10(-3) J increased the blocking effect of 10 microM bupivacaine on the slow potassium current, while an irradiation dose of 0.7 x 10(-4) J weakened the effect of bupivacaine.

  7. Combined Effect of Low-Intensity Helium-Neon Laser and X-Ray Radiation on in Vivo Cellular Response of the Whole Blood and Lymphoid Organs in Mice.

    Science.gov (United States)

    Zaichkina, S I; Dyukina, A R; Rozanova, O M; Romanchenko, S P; Sirota, N P; Kuznetsova, E A; Simonova, N B; Sorokina, S S; Zakrzhevskaya, D T; Yusupov, V I; Bagratishvili, V N

    2016-09-01

    We studied the effect of exposure to helium-neon laser (dose range 0.16-50 mJ/cm2) on activation of natural protection reserve in mice using the adaptive response test. DNA comets method revealed a protective response manifested in DNA damage level in whole blood leukocytes of mice and in lymphoid organs by the thymus and spleen weight index; preexposure to laser did not induce the adaptive response. ROS level in the whole blood was assessed by the level of zymosan-induced luminol chemiluminescence. In mice subjected to adaptive laser irradiation in doses of 0.16-5 mJ/cm2 followed by X-ray irradiation in a dose of 1.5 Gy, the activation index calculated as the ratio of induced to spontaneous area of luminescence was by 1.4 times lower than that in non-irradiated animals, which attested to reduced ROSgeneration reserve capacity of neutrophils.

  8. Helium-neon laser irradiation at fluences of 1, 2, and 4 J/cm2 failed to accelerate wound healing as assessed by both wound contracture rate and tensile strength.

    Science.gov (United States)

    Allendorf, J D; Bessler, M; Huang, J; Kayton, M L; Laird, D; Nowygrod, R; Treat, M R

    1997-01-01

    Reports in the literature indicate that low energy laser irradiation has a biostimulatory effect on wound healing; however, no mechanism of this effect has been elucidated. We attempted to establish a model from which to study the mechanism of biostimulation. The effects of low energy helium-neon irradiation on wound healing were observed in two rat models. In the first model, 1.5 cm diameter full thickness excisional skin defects were created in the dorsal midline of rats (n = 32). All animals were anesthetized and all eschars were debrided daily. Wound area was determined by caliper measurements for 2 weeks postoperatively. Rats that received a treatment of 1 J/cm2 had two defects in the dorsal skin. One wound was treated and the second was used as its own control. These measurements were not blinded. Rats that received 2 J/cm2, 4 J/cm2, or anesthesia alone had one defect on the dorsal skin. Caliper measurements of these wounds were blinded. We were unable to demonstrate any difference in the rate of wound contracture in rats that received a daily dose of 1 J/cm2, 2 J/cm2, 4 J/cm2, or anesthesia alone (P > 0.8 by student's t-test). In the second model, a single 2 cm longitudinal full thickness skin incision was created in the dorsal midline of each rat (n = 24). No difference was found between rats that received anesthesia alone and those treated daily with 2 J/cm2 as assessed by tensile strength measurements on postoperative days 7 and 14 (P > 0.8 by student's t-test between groups at both time points). These determinations were blinded. Despite our intentions of studying the mechanism of low energy HeNe biostimulation, we were unable to demonstrate a beneficial effect. In this study, helium-neon laser irradiation produced no measurable benefit on wound healing.

  9. Formation of long-lived reactive species of blood serum proteins induced by low-intensity irradiation of helium-neon laser and their involvement in the generation of reactive oxygen species.

    Science.gov (United States)

    Ivanov, Vladimir E; Usacheva, Anna M; Chernikov, Anatoly V; Bruskov, Vadim I; Gudkov, Sergey V

    2017-11-01

    It was demonstrated that low-intensity radiation of helium-neon (He-Ne) laser at 632.8nm, which leads to the transition of oxygen to a singlet state, causes the formation of reactive oxygen species (ROS) - hydrogen peroxide, hydroxyl and superoxide (hydroperoxide) radicals - in aqueous solutions. The oxygen effect - dependence of hydrogen peroxide formation on the concentration of molecular oxygen - was shown, and the participation of singlet oxygen, hydroxyl radicals and superoxide (hydroperoxide) radicals in this process was testified. Laser radiation-induced ROS in solutions of blood serum proteins, bovine serum albumin and bovine gamma-globulin, cause the formation of long-lived reactive protein species (LRPS) with a half-life of about 4h. The generation of LRPS caused by laser irradiation results in prolonged several-hour generation of ROS - hydrogen peroxide, hydroxyl and superoxide radicals. As affected by LRPS, coupled radical reactions lead to conversion of dissolved molecular oxygen to hydrogen peroxide. Irradiation with light sources away from the oxygen absorption band is not attended by formation of ROS and LRPS. A consideration is provided for the possible molecular mechanisms of ROS formation under the influence of He-Ne laser irradiation, the role of proteins in their generation and the biological significance of these processes. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Effect of single-dose low-level helium-neon laser irradiation on orthodontic pain: a split-mouth single-blind placebo-controlled randomized clinical trial.

    Science.gov (United States)

    Sobouti, Farhad; Khatami, Maziar; Chiniforush, Nasim; Rakhshan, Vahid; Shariati, Mahsa

    2015-01-01

    Pain is the most common complication of orthodontic treatment. Low-level laser therapy (LLLT) has been suggested as a new analgesic treatment free of the adverse effects of analgesic medications. However, it is not studied thoroughly, and the available studies are quite controversial. Moreover, helium neon (He-Ne) laser has not been assessed before. This split-mouth placebo-controlled randomized clinical trial was performed on 16 male and 14 female orthodontic patients requiring bilateral upper canine retraction. The study was performed at a private clinic in Sari, Iran, in 2014. It was single blind: patients, orthodontist, and personnel were blinded of the allocations, but the laser operator (periodontist) was not blinded. Once canine retractor was activated, a randomly selected maxillary quarter received a single dose of He-Ne laser irradiation (632.8 nm, 10 mw, 6 j/cm(2) density). The other quarter served as the placebo side, treated by the same device but powered off. In the first, second, fourth, and seventh days, blinded patients rated their pain sensed on each side at home using visual analog scale (VAS) questionnaires. There was no harm identified during or after the study. Pain changes were analyzed using two- and one-way repeated-measures ANOVA, Bonferroni, and t-test (α = 0.01, β > 0.99). This trial was not registered. It was self-funded by the authors. Sixteen males and 11 females remained in the study (aged 12-21). Average pain scores sensed in all 4 intervals on control and laser sides were 4.06 ± 2.85 and 2.35 ± 1.77, respectively (t-test P < 0.0001). One-way ANOVA showed significant pain declines over time, in each group (P < 0.0001). Two-way ANOVA showed significant effects for LLLT (P < 0.0001) and time (P = <0.0001). Single-dose He-Ne laser therapy might reduce orthodontic pain caused by retracting maxillary canines.

  11. Improvement of the antifungal activity of Litsea cubeba vapor by using a helium-neon (He-Ne) laser against Aspergillus flavus on brown rice snack bars.

    Science.gov (United States)

    Suhem, Kitiya; Matan, Narumol; Matan, Nirundorn; Danworaphong, Sorasak; Aewsiri, Tanong

    2015-12-23

    The aim of this study was to improve the antifungal activity of the volatile Litsea cubeba essential oil and its main components (citral and limonene) on brown rice snack bars by applying He-Ne laser treatment. Different volumes (50-200 μL) of L. cubeba, citral or limonene were absorbed into a filter paper and placed inside an oven (18 L). Ten brown rice snack bars (2 cm wide × 4 cm long × 0.5 cm deep) were put in an oven and heated at 180 °C for 20 min. The shelf-life of the treated snack bars at 30 °C was assessed and sensory testing was carried out to investigate their consumer acceptability. A count of total phenolic content (TPC) and Fourier transform infrared spectroscopy (FTIR) on the properties of essential oil, citral, and limonene before and after the laser treatment was studied for possible modes of action. It was found that the laser treatment improved the antifungal activity of the examined volatile L. cubeba and citral with Aspergillus flavus inhibition by 80% in comparison with those of the control not treated with the laser. L. cubeba vapor at 100 μL with the laser treatment was found to completely inhibit the growth of natural molds on the snack bars for at least 25 days; however, without essential oil vapor and laser treatment, naturally contaminating mold was observed in 3 days. Results from the sensory tests showed that the panelists were unable to detect flavor and aroma differences between essential oil treatment and the control. Laser treatment caused an increase in TPC of citral oil whereas the TPC in limonene showed a decrease after the laser treatment. These situations could result from the changing peak of the aliphatic hydrocarbons that was revealed by the FTIR spectra. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Photo-stimulatory effect of low energy helium-neon laser irradiation on excisional diabetic wound healing dynamics in wistar rats

    Directory of Open Access Journals (Sweden)

    Maiya Arun

    2009-01-01

    Full Text Available Background: Generally, the significances of laser photo stimulation are now accepted, but the laser light facilitates wound healing and tissue repair remains poorly understood. Aims: We have examined the hypothesis that the laser photo stimulation can enhance the collagen production in diabetic wounds using the excision wound model in the Wistar rat model. Methods: The circular wounds were created on the dorsum of the back of the animals. The animals were divided into two groups. The study group (N = 24 wound was treated with 632.8 nm He-Ne laser at a dose of 3-9J/cm 2 for 5 days a week until the wounds healed completely. The control group was sham irradiated. Result: A significant increase in the hydroxyproline content and reduction in the wound size were observed in the study group. The pro-healing actions seem to be due to increased collagen deposition as well as better alignment and maturation. Conclusion: The biochemical analysis and clinical observation suggested that 3-6 J/cm 2 laser photo stimulation facilitates the tissue repair process by accelerating collagen production in diabetic wound healing.

  13. Láser helio-neón combinado con clorhexidina al 0,2 %.: Efectos clínicos y microbiológicos en el tratamiento de la gingivitis crónica Helium-neon laser combined with 0.2% chlorhexidine: Clinical and microbiological effects in the treatment of chronic gingivitis.

    Directory of Open Access Journals (Sweden)

    Tatiana Peña Ruiz

    2007-09-01

    Full Text Available La gingivitis crónica constituye una de las formas más frecuentes de enfermedad periodontal, caracterizada por la inflamación crónica de la encías, tumefacción, enrojecimiento y sangramiento. Su principal factor de riesgo lo constituye la microbiota del surco gingival, que resulta necesario, pero no suficiente para desencadenarla. Se realizó un ensayo clínico-terapéutico fase II, controlado, aleatorizado y a simple ciegas, para evaluar los efectos clínicos y microbiológicos del tratamiento combinado de la radiación láser helio-neón (He-Ne con la clorhexidina al 0,2 %. Todos los pacientes recibieron tratamiento inicial; al mes de finalizado este, se distribuyeron aleatoriamente en 2 grupos: un grupo estudio que recibió la combinación láser-neón y clorhexidina al 0,2 % y otro grupo control que solo recibió clorhexidina al 0,2 %. Se realizó una evaluación a los 15, 30 y 45 días, con criterios de eficacia clínicos y microbiológicos. Los resultados clínicos fueron satisfactorios en el grupo estudio con predominio de los morfotipos I, caracterizados por cocos gramnegativos y positivos, compatibles con un periodonto sano. Los eventos adversos detectados con esta terapéutica fueron mínimos, todos relacionados con la somnolencia.Chronic gingivitis is one of the most common periodontal diseases that is characterized by chronic inflammation, tumefaction, redness and bleeding. The main risk factor is gingival sulcus microbiota that is essential but not enough to unleash it. A phase II controlled randomized blind clinical/therapeutical assay was conducted to evaluate the clinical and microbiological effects of the combined treatment based on helium-neon laser (He-Ne with 0.2% chlorhexidine. All the patients were initially treated; after a month, they were randomly distributed into two groups, that is, the study group received a helium-neon laser plus 0.2% chlorhexidine combination and the control group was treated with 0

  14. Os efeitos do laser hélio-neônio de baixa intensidade na cicatrização de lesões cutâneas induzidas em ratos Effects of low-level helium-neon laser on induced wound healing in rats

    Directory of Open Access Journals (Sweden)

    Viviane L. Busnardo

    2010-02-01

    Full Text Available OBJETIVO: Avaliar os efeitos do laser de baixa potência hélio e neônio (HeNe na cicatrização de feridas cutâneas de ratos. MÉTODOS: Sessenta ratos Wistar foram divididos em grupos controle e experimento. Utilizou-se ferida incisional, longitudinal, dorso-mediana, suturada com pontos separados simples. No grupo experimento, as feridas foram irradiadas diariamente com aparelho de laser de HeNe com potência contínua máxima de 5mW, comprimento de onda de 632,8 nm, visível com densidade de energia de 4J/cm², área de raio do laser de 0,015cm², durante 36 segundos, em três pontos da lesão. As feridas foram avaliadas no 3º, no 7º e no 14º dia de pós-operatório. Cortes histológicos foram corados com hematoxilina-eosina (H&E e avaliados segundo protocolo de Vizzotto et al. (2003* para identificar o tipo de reação inflamatória e com Picrosirius para identificar os colágenos I e III e o índice de maturidade da cicatriz (IMaC. Utilizou-se imunoistoquímica com anti-CD45-LCA para o reconhecimento das células inflamatórias. RESULTADOS: Ambos os grupos mostraram o mesmo padrão inflamatório. No grupo experimento, observaram-se menos células inflamatórias nos três tempos estudados (pOBJECTIVE: To evaluate the effects of low-level helium-neon (HeNe laser on cutaneous wound healing in rats. METHODS: Sixty Wistar rats were divided into control group and experimental group. A sutured longitudinal, dorsal-medial incision was made, with simple separate stitches. The experimental group was irradiated daily in three areas of the wound with HeNe laser (5mW maximum continuous power, 632.8 nm wavelength, 4 J/cm² energy density and 0.015 cm² laser beam area for 36 seconds. The areas were evaluated on the third, seventh and fourteenth days postoperative. Histological sections were stained with hematoxylin-eosin to determine the type of inflammatory reaction according to the protocol by Vizzotto et al. (2003* and with Picrosirius to identify

  15. [Age-related peculiarities of thymus reaction to the exposure to helium-neon laser and injured muscle alloplasty with the muscle tissue from the animals of the same age].

    Science.gov (United States)

    Bulyakova, N V; Azarova, V S

    2015-01-01

    Histological, cytological and morphometric changes in the thymus of 1 month-old, adult (3-4 months-old) and old (24-30 months-old) rats (24 animals in each group) were studied during muscle regeneration after the alloplasty of the injured area with the muscle tissue from the animal of the same age. Muscles of the donor or recipient were subjected to the course of preliminary irradiation with He-Ne laser (dose: 4.5-5.4 J/cm2 for each extremity; total dose of 9.0-10.8 J/cm2 per animal). It was shown that the exposure of gastrocnemius muscles that were prepared for the operation to He-Ne laser radiation decreased morpho-functional activity of the thymus in young, adult and old recipient rats the before surgery. This was demonstrated by its weaker reaction to the allograft during the early time intervals after surgery. The observed effect was more pronounced with the increasing age of an animal.

  16. Transport coefficients of helium-neon mixtures at low density computed from ab initio potentials.

    Science.gov (United States)

    Sharipov, Felix; Benites, Victor J

    2017-12-14

    The viscosity, thermal conductivity, diffusion coefficient, and thermal diffusion factor of helium-neon mixtures at low density are calculated for a wide range of temperature and for various molar fractions. The Chapman-Enskog method is employed considering the 10th order of the Sonine polynomial expansion. Ab initio potentials for intermolecular interactions are used to calculate the omega-integrals. The relative numerical error of the present results obtained for the potentials used here is less than 7 × 10-5 for the thermal diffusion factor and 2 × 10-5 for all the other coefficients. Since each employed potential has a different accuracy, the uncertainty related to such accuracies was analyzed, considering the contribution of each potential uncertainty. It was found that the total uncertainty due to the potentials is larger than the numerical error and it varies depending on the temperature and molar fraction. A comparison of the calculated transport coefficients with those available in the open literature shows that the present calculations provide the most accurate values currently available for the transport coefficients of helium-neon binary mixtures at low density.

  17. The effects of helium-neon light therapy on healing of partial osteotomy of the tibia in streptozotocin induced diabetic rats.

    Science.gov (United States)

    Abdi, Shabnam; Bayat, Mohammad; Javadieh, Farshad; Mohsenifar, Zhaleh; Rezaie, Fatemesadat; Bayat, Maryam

    2009-12-01

    The effect of light therapy (LT) on surgically created partial osteotomy in streptozotocin (STZ)-induced diabetic rats was examined. LT has been shown to enhance bone repair in healthy human and animal models. Forty male rats were divided into groups 1 to 5. Diabetes was induced in rats of groups 1, 2, and 3 using an intraperitoneal injection of STZ. All diabetic rats were maintained for 30 days after STZ injection. Under general anesthesia and sterile conditions, a partial transversal standardized osteotomy was made in the mid-portion of the right tibia. The defects in groups 2, 3, and 5 were treated using a helium-neon (He-Ne) laser (632.8 nm, 10 mW, circular beam shape). Groups 1 and 4 were diabetic placebo and normal placebo groups, respectively. A dose of 369.4 J/cm2 for groups 2 and 5 and a dose of 66.8 J/cm2 for group 3 were applied three times a week. Six weeks after surgery, the right tibia was collected. The specimen was subjected to a three-point bending test. LT with 369.4 J/cm2 energy density resulted in significantly greater bending stiffness in group 5 (41.8+/-5.2) than in groups 1 (18.5+/-4.1), 2 (17.7+/-1.6), and 3 (11.5+/-4) (least significant difference (LSD) test, p<0.01, p<0.001, and p<0.001, respectively). LT with 369.4 J/cm2 energy density resulted in a significantly higher stress load in group 5 (10+/-0.4) than in groups 1 (4.9+/-1.5), 2 (5.7+/-0.52), and 3 (3.9+/-1.1) (LSD test, p<0.01, p<0.01, p<0.001, respectively). LT with a He-Ne laser in STZ-induced diabetic rats did not enhance bone repair of a partial transversal standardized osteotomy.

  18. Ab initio calculation of the interaction potentials of helium, neon, and methane as well as theoretical studies on their thermophysical properties and those of water vapor; Ab initio-Berechnung der Wechselwirkungspotentiale von Helium, Neon und Methan sowie theoretische Untersuchungen zu ihren thermophysikalischen Eigenschaften und denen von Wasserdampf

    Energy Technology Data Exchange (ETDEWEB)

    Hellmann, Robert

    2009-06-16

    Thermophysical properties of the pure gases helium, neon, methane and water vapor were calculated for low densities over wide temperature ranges. Statistical thermodynamics was used for the determination of the pressure virial coefficients. The kinetic theory of gases was utilized for the calculation of the transport and relaxation properties. So far kinetic theory was limited to linear molecules and has now been extended to molecules of arbitrary geometry to enable calculations on methane and water vapor. The interaction potentials, which are needed for all computations, were determined for helium, neon and methane from the supermolecular approach using quantum chemical ab initio methods. For water the interaction potentials were taken from the literature. The calculated values of the thermophysical properties for the four gases show very good agreement with the best experimental data. At very low and very high temperatures the theoretical values are more accurate than experimental data. (orig.)

  19. Intermolecular dispersion interactions of normal alkanes with rare gas atoms: van der Waals complexes of n-pentane with helium, neon, and argon

    Energy Technology Data Exchange (ETDEWEB)

    Balabin, Roman M. [Gubkin Russian State University of Oil and Gas, 199991 Moscow (Russian Federation)], E-mail: balabin.r@gubkin.ru

    2008-09-03

    Interaction energies of normal pentane with three rare gas atoms (helium, neon, and argon) were calculated using ab initio methods: the second-order Moller-Plesset (MP2), the fourth-order Moller-Plesset (MP4), and coupled cluster with single and double substitutions with noniterative triple excitation (CCSD(T)) levels of theory. Dunning's correlation consistent basis sets up to aug-cc-pVQZ were applied. Eight profiles (246 points for each rare gas atom) of potential energy surface (PES) of all-trans (anti-anti) conformation of n-pentane were scanned. Optimal distances for complex formation were found. MP2 interaction energies at the basis set limit were evaluated by three different methods (Feller's, Helgaker's, and Martin's). The MP2 interaction energy at the basis set limit for a global minimum of n-pentane complex with argon was more than 400 cm{sup -1}, so formation of a stable complex (at least at low temperature) can be expected. A comparison with previously published data on propane complexes with rare gas atoms (both computational and experimental) was done. The MP4 level of theory was found to be sufficient for a description of C{sub 5}H{sub 12} complexes with helium, neon, and argon.

  20. On the origins of trapped helium, neon and argon isotopic variations in meteorites. I - Gas-rich meteorites, lunar soil and breccia. II - Carbonaceous meteorites.

    Science.gov (United States)

    Black, D. C.

    1972-01-01

    Data are presented from stepwise heating experiments and total extractions on five meteorites: Kapoeta, Fayetteville, Holman Island, Cee Vee, and Pultusk. These data reveal the presence of four isotopically distinct trapped neon components. A comparison of trapped neon with trapped helium and argon in bulk analyses indicates the existence of correlated helium, neon and argon isotopic structures. Component B is attributed primarily to direct implantation of rare gas ions by the present day solar wind. Component C is identified with directly implanted low energy (1-10 Mev/n) solar flare rare gases. Component D is associated with rare gas ions implanted in meteoritic material by the primitive, pre-main sequence, solar wind. A fourth component, observed only in Kapoeta and the lunar fines and breccia, is tentatively attributed to parent body 'atmospheric' ions implanted in surface material by a solar wind induced electric field.

  1. Correction of biochemical and functional disorders in brain ischaemia with laser therapy

    Science.gov (United States)

    Musienko, Julia I.; Nechipurenko, Natalia I.; Vasilevskaya, Ludmila A.

    2005-08-01

    Application of intravenous laser irradiation of blood (ILIB) is considered to be the most effective method of laser therapy and its application is expedient pathogenetically in the ischemic disturbances. The aim of this study is to investigate ILIB influence with red helium-neon laser (HNL) with 630 nm wavelength and different powers on blood oxygen transport (BOT), cerebral and dermal microhaemodynamics (MGD), hydro-ion balance in normal rabbits and after modeling of local ischemia of brain (LIB). Experimental cerebral ischemia is characterized by development of BOT disturbance, ionic disbalance and edema in the ischemic brain region. Microcirculation disturbances with worsening of the cerebral and dermal MHD were revealed. ILIB with HNL radiation of 2.5 and 4.5 mW powers provokes dehydratation of brain structure alone with the K+, Na+ concentration decreasing and hemoglobin-oxygen affinity increasing in intact group of animals. There was not revealed marked changes of cerebral MHD condition here. Using of ILIB in rabbits after LIB contributes for improving function of BOT, normalizing of water content in all cerebral structures compared to operated animals. Preventive ILIB provoked improvement of speckl-optical parameters and marked protective effect on microhaemodynamics processes in superficial brain structures. HNL radiation with 1.0 mW power results in worsening of oxygen transport, cerebral and skin MHD, hydro-ion homeostasis in animals with LIB modeling. Thus, laser haemotherapy contributes for improving of hydro-ion status, blood oxygen transport and cerebral microcirculation in brain ischemia, what allows considering that helium-neon radiation with the pointed regimen is substantiated pathogenetically in brain ischaemia.

  2. Low-level laser therapy in chemo- and radiation-induced mucositis: results of multicenter phase III studies

    Science.gov (United States)

    Bensadoun, Rene-Jean

    2001-04-01

    Low of middle energy irradiation with helium-neon laser (LLLT) appears to be a simple atraumatic technique for the prevention and treatment of mucositis of various origins. Preliminary findings obtained by Ciais et al prompted randomized multi-center, double-blind trials to evaluate LLLT for the prevention of a acute chemo- and radiation- induced stomatitis. Irradiation by LLLT corresponds to local application of a high photon density monochromatic light source. Activation of epithelial healing on LLL-treated surfaces, the most commonly recognized effect, has been confirmed by numerous in vitro studies, and is a function of cell type, wavelength, and energy dose. The mechanism of action at a molecular and enzymatic level is currently being studied (detoxification of free-radicals).

  3. Interferometry and Holography With Diode Laser Light

    CERN Document Server

    Lunazzi, Jose Joaquin

    2016-01-01

    We made an interferometric Michelson type setup and a simple holographic setup to demonstrate the feasibility of interferometric and holographic techniques by means of a diode laser. The laser was made by using a common diode available as a penlight element (less than R$ 15,00 value) and a simple stabilized 110 VCA- 3 VCC power supply. Interference fringes and holograms of small objects where obtained very similar to those of a helium-neon laser based setup.

  4. Role of nitric oxide in the reaction of arterial vessels to laser irradiation.

    Science.gov (United States)

    Chertok, V M; Kotsyuba, A E; Bespalova, E V

    2008-06-01

    Reactivity of arterial vessels in the small intestine mesentery to irradiation with a helium-neon laser before and after NO synthase blockade was studied by means of biomicroscopy. Blood flow velocity and vascular diameter increased under conditions of laser irradiation. During irradiation, arterial vasodilation was inversely related to the initial diameter. After treatment with NO synthase inhibitor, the dilatory response of vessels to laser irradiation was completely abolished (arteries, diameter >80 micro) or decreased by 2 times (arterioles, diameter <50 micro).

  5. Low power laser irradiation does not affect the generation of signals in a sensory receptor

    Energy Technology Data Exchange (ETDEWEB)

    Lundeberg, T.; Zhou, J.

    1989-01-01

    The effect of low power Helium-Neon (He-Ne) and Gallium-Arsenide (Ga-As) laser on the slowly adapting crustacean stretch receptor was studied. The results showed that low power laser irradiation did not affect the membrane potential of the stretch receptor. These results are discussed in relation to the use of low power laser irradiation on the skin overlaying acupuncture points in treatment of pain syndrome.

  6. Laser treatment of otitis media in children

    Energy Technology Data Exchange (ETDEWEB)

    Podoynitsyna, L.F.

    1984-08-01

    Clinical trials were conducted with the helium-neon LG-75 laser (632.8 nm, 0.1 W/cm/sup 2/) in the management of 50 children with acute and chronic otitis media. The sessions consisted of 30 sec irradiation directed at the middle ear through the external meatus for a period of 5 days. Positive results were obtained in 45 of the patients with cessation of discharge on the 2nd or 3rd day, and return of hearing by the end of the week. The remission was not permanent in one patient with recurrent otitis media. These observations indicate that the anti-inflammatory effects of helium-neon irradiation constitute an effective treatment modality in children with otitis media. 6 references.

  7. Low energy laser irradiation treatment for second intention wound healing in horses

    Science.gov (United States)

    Fretz, Peter B.; Li, Zhong

    1992-01-01

    Low energy helium-neon laser irradiation was administered to full thickness skin wounds (3 cm × 3 cm) on the dorsal surface of the metacarpophalangeal/metatarsophalangeal joints and cranial surface of the tarsocrural joints of eight horses. The effects on wound healing were analyzed statistically. There were no differences (p > 0.55) observed in the rate of wound healing between the low energy laser irradiated wounds and the control wounds. There was a significant difference (p fetlock wounds. PMID:17424089

  8. Orthogonal polarization in lasers physical phenomena and engineering applications

    CERN Document Server

    Zhang, Shulian

    2013-01-01

    This practical book summarizes the latest research results of orthogonally polarized lasers, birefringence laser cavities, and their applications. Coverage ranges from basic principles and technologies to the characteristics of different cavities and lasers to various measurement techniques. A number of figures, experimental designs, and measurement curves are included, helping readers gain a thorough understanding of the many applications in modern engineering and start their own projects. Many types of relevant lasers (Helium/Neon lasers, Nd:YAG lasers, laser diodes, etc.) are also discussed

  9. Link Performance Analysis of a Ship-to-Ship Laser Communication System

    Science.gov (United States)

    2012-03-01

    helium- neon (HeNe), carbon dioxide (CO2), and argon (Ar), to produce a coherent light. The dye laser is produced by directing a high-energy source of...molecules in the atmosphere that contribute to absorption are the oxygen (O2), nitrogen (N2), carbon 28 dioxide (CO2), argon (Ar), methane (CH4...error rate and explains the parameters of the link budget. The fifth chapter provides an example of a link budget calculation and discusses the

  10. Low-energy He/Ne laser in the prevention of radiation-induced mucositis. A multicenter phase III randomized study in patients with head and neck cancer.

    Science.gov (United States)

    Bensadoun, R J; Franquin, J C; Ciais, G; Darcourt, V; Schubert, M M; Viot, M; Dejou, J; Tardieu, C; Benezery, K; Nguyen, T D; Laudoyer, Y; Dassonville, O; Poissonnet, G; Vallicioni, J; Thyss, A; Hamdi, M; Chauvel, P; Demard, F

    1999-07-01

    Use of the low-energy helium-neon laser (LEL) appears to be a simple atraumatic technique for the prevention and treatment of mucositis of various origins. Preliminary findings, and significant results obtained for chemotherapy-induced mucositis in a previous phase III study, prompted a randomized multicenter double-blind trial to evaluate LEL in the prevention of acute radiation-induced stomatitis. Irradiation by LEL corresponds to local application of a high-photon-density monochromatic light source. Activation of epithelial healing for LEL-treated surfaces, the most commonly recognized effect, has been confirmed by numerous in vitro studies. The mechanism of action at a molecular and enzymatic level is presently being studied. From September 1994 to March 1998, 30 patients were randomized. Technical specification: 60 mW (25 mW at Reims, 1 patient), He-Ne, wavelength 632.8 nm. The trial was open to patients with carcinoma of the oropharynx, hypopharynx and oral cavity, treated by radiotherapy alone (65 Gy at a rate of 2 Gy/fraction, 5 fractions per week) without prior surgery or concomitant chemotherapy. The malignant tumor had to be located outside the tested laser application areas (9 points): posterior third of the internal surfaces of the cheeks, soft palate and anterior tonsillar pillars. Patients were randomized to LEL or placebo light treatment, starting on the first day of radiotherapy and before each session. The treatment time (t) for each application point was given by the equation : t(s)= energy (J/cm2) x surface (cm2)/Power (W). Objective assessment of the degree of mucositis was recorded weekly by a physician blinded to the type of treatment, using the WHO scale for grading of mucositis and a segmented visual analogue scale for pain evaluation. Protocol feasibility and compliance were excellent. Grade 3 mucositis occured with a frequency of 35.2% without LEL and of 7.6% with LEL (Ptherapy is capable of reducing the severity and duration of oral

  11. GASP: A computer code for calculating the thermodynamic and transport properties for ten fluids: Parahydrogen, helium, neon, methane, nitrogen, carbon monoxide, oxygen, fluorine, argon, and carbon dioxide. [enthalpy, entropy, thermal conductivity, and specific heat

    Science.gov (United States)

    Hendricks, R. C.; Baron, A. K.; Peller, I. C.

    1975-01-01

    A FORTRAN IV subprogram called GASP is discussed which calculates the thermodynamic and transport properties for 10 pure fluids: parahydrogen, helium, neon, methane, nitrogen, carbon monoxide, oxygen, fluorine, argon, and carbon dioxide. The pressure range is generally from 0.1 to 400 atmospheres (to 100 atm for helium and to 1000 atm for hydrogen). The temperature ranges are from the triple point to 300 K for neon; to 500 K for carbon monoxide, oxygen, and fluorine; to 600 K for methane and nitrogen; to 1000 K for argon and carbon dioxide; to 2000 K for hydrogen; and from 6 to 500 K for helium. GASP accepts any two of pressure, temperature and density as input conditions along with pressure, and either entropy or enthalpy. The properties available in any combination as output include temperature, density, pressure, entropy, enthalpy, specific heats, sonic velocity, viscosity, thermal conductivity, and surface tension. The subprogram design is modular so that the user can choose only those subroutines necessary to the calculations.

  12. Generation of electron beams from a laser-based advanced accelerator at Shanghai Jiao Tong University

    CERN Document Server

    Elsied, Ahmed M M; Li, Song; Mirzaie, Mohammad; Sokollik, Thomas; Zhang, Jie

    2014-01-01

    At Shanghai Jiao Tong University, we have established a research laboratory for advanced acceleration research based on high-power lasers and plasma technologies. In a primary experiment based on the laser wakefield acceleration (LWFA) scheme, multi-hundred MeV electron beams having a reasonable quality are generated using 20-40 TW, 30 femtosecond laser pulses interacting independently with helium, neon, nitrogen and argon gas jet targets. The laser-plasma interaction conditions are optimized for stabilizing the electron beam generation from each type of gas. The electron beam pointing angle stability and divergence angle as well as the energy spectra from each gas jet are measured and compared.

  13. The intravenous laser blood irradiation in chronic pain and fibromyalgia.

    Science.gov (United States)

    Momenzadeh, Sirous; Abbasi, Mohammadzaki; Ebadifar, Asghar; Aryani, Mohammadreza; Bayrami, Jafar; Nematollahi, Fatemeh

    2015-01-01

    Intravenous laser blood irradiation was first introduced into therapy by the Soviet scientists EN.Meschalkin and VS.Sergiewski in 1981. Originally this method was developed for the treatment of cardiovascular diseases. Improvement of rheologic properties of the blood as well as improvement of microcirculation and reduction of the area of infarction has been proved. Further, reduction of dysrhythmia and sudden cardiac death was achieved. At first, only the Helium-Neon laser (632.8 nm) was used in this therapy. For that, a power of 1-3mW and a period of exposure of 20-60 minutes were applied. The treatments were carried out once or twice a day up to ten appointments in all1. In the years after, many, and for the most part Russian studies showed that helium-neon laser had various effects on many organs and on the hematologic and immunologic system. The studies were published mainly in Russian which were little known in the West because of decades of political separation, and were regarded with disapproval. Besides clinical research and application for patients, the cell biological basis was developed by the Estonian cell biologist Tiina Karu at the same time. An abstract is to be found in her work "The Science of Low-Power Laser-Therapy"

  14. Laser signals' nonlinear change in fatty acids

    CERN Document Server

    Ghelmez-Dumitru, M; Piscureanu, M; Sterian, A

    2003-01-01

    Previous works showed that thin layers of fatty acids and fatty acid-cholesterol mixtures behaved as optical liquid crystals, even at low incident laser power. The paper presents an experimental and computer study of laser signals, emergent from such samples, in presence of fluctuations. The optical emergent laser beams' features at different incident parameters were experimentally determined for different type (c.w. and pulsed) lasers, as for example helium-neon and Nd sup 3 sup + glass lasers. The results were correlated with the amount of cholesterol in mixtures and with their response in external electric field. These measurements are in all cases affected by fluctuations. We developed some computer-based procedures, by using the TableCurve3D from Jandel Scientific software and equations Runge-Kutta in MATLAB for taking into account these fluctuations.

  15. Laser puncture therapy of nervous system disorders

    Energy Technology Data Exchange (ETDEWEB)

    Anishchenko, G.; Kochetkov, V.

    1984-08-29

    The authors discuss experience with treatment of nervous system disorders by means of laser-puncture therapy. Commenting on the background of the selection of this type of treatment, they explain that once researchers determined the biological action of laser light on specific nerve receptors of the skin, development of laser apparatus capable of concentrating the beam in the millimeter band was undertaken. The devices that are being used for laser-puncture are said to operate in the red helium-neon band of light. The authors identify beam parameters that have been selected for different groups of acupuncture points of the skin, and the courses of treatment (in seconds of radiation) and their time intervals. They go on to discuss the results of treatment of over 800 patients categorized in a group with disorders of the peripheral nervous system and a second group with disorders of the central nervous system.

  16. [The influence of extracorporeal laser radiation on structural indices of erythrocytes].

    Science.gov (United States)

    Khetsuriani, R G; Aladashvili, L M; Arabuli, M B; Tophuria, D Z; Tchlikadze, N G

    2015-01-01

    Object of the research was to study the diffractometric indices of erythrocytes, while 1 ml of the blood of the experimental animals was irradiated extracorporally by helium-neon laser. For this purpose 1 ml blood was taken from normal weight, (1200 gr) grown up shinshila rabbits, that we divided into 7 groups and irradiated with 10 vat helium-neon laser during 0.5-1 minutes. After irradiation blood was injected back to the organism of rabbits. After 2-6 hours from irradiation blood was taken from veins, to study by electronic microscope and later to be processed by diffractometric analysis method. The examinations testify that after extracorporeal irradiation diffractometric characteristics of erythrocytes' membranes are lower than after general irradiation, which indicates to the different energetic possibilities of laser. The extracorporeal irradiation, performed by laser and input of radiated blood back to organism is considered to be a shock therapy from the side of erythrocytes, which promote the defense function of the organism itself. The base for the shock therapy should be important factors such as homeostasis, compensative-adaptive mechanisms and so on. Exactly this above mentioned should be manifested after the sensitized cells are led back to the body (1 ml of blood) and with their existence they should promote display of the defense mechanisms.

  17. Evaluating the effectiveness of the treatment of inflammatory periodontal disease on a background of chronic cholecystitis with the combined effect of the running of the alternating magnetic fields and low-intensity laser radiation

    Directory of Open Access Journals (Sweden)

    Dyakova E.S.

    2011-03-01

    Full Text Available The aim of the study was to determine the characteristic clinical, instrumental and diagnostic criteria of inflammatory periodontal diseases on the background of chronic cholecystitis with subsequent evaluation of the effectiveness of therapeutic measures using the combined action of the running of an alternating magnetic field and low-intensity helium-neon laser. Application low-intensiti laser radiation and a running variable magnetic field in complex treatment of patients periodontitis with cholecystitis expressed anti-inflammatory action allows to stop quickly inflammatory process in periodontium and to reduce treatment terms

  18. FROM THE HISTORY OF LASER CREATION

    Directory of Open Access Journals (Sweden)

    I.M. Belousova

    2014-03-01

    Full Text Available The paper briefly describes the history of formation of a new science direction - quantum electronics, associated with the discovery of masers and lasers by scientists from the USA (Ch. Townes and the USSR (N.G. Basov and A. M. Prokhorov. The world's first ruby laser designed by T. Maiman is described. Some historical events devoted to creation and research of lasers are given in which the author of the paper as well as research workers from Vavilov State Optical Institute, ITMO University and LOMO have taken direct part in the development of solid-state and gas lasers (helium-neon, photodissociation, CO2-lasers and laser optical systems. Contribution of researchers from Vavilov State Optical Institute, LOMO and ITMO University to large-scale programs on development of lasers for laser nuclear fusion, laser weapons and “Phobos” program is shown. The paper deals in brief with new issues of development and application of lasers, mainly, within the project of laser orbital space station of the future, for the conversion of solar energy into laser radiation. Description of idea of solar energy transformation by fullerene-oxygen laser is presented. The patent for it has been taken out by Vavilov State Optical Institute. Developed fullerene-oxygen-iodine laser and laser structure models for industrial applications and solar energy conversion into laser radiation are described. Parameters for hypothetical laser-optical system of the future space station are given.

  19. Solid-state ring laser gyro for aerospace applications

    Science.gov (United States)

    Schwartz, Sylvain; Gutty, François; Feugnet, Gilles; Pocholle, Jean-Paul; Desilles, Gaël.

    2017-11-01

    We report on the development of a prototype solidstate ring laser gyro based on a diode-pumped neodymium-doped yttrium aluminum garnet crystal as the gain medium. We describe in this paper how we circumvent mode competition between the counter-propagating modes using a feedback loop acting on the differential losses. We then show how the non-linear frequency response can be significantly improved by vibrating the gain medium along the laser axis, leading to a behavior similar as a typical Helium-Neon ring laser gyro. We finally discuss the undergoing improvements for achieving high inertial performance with this device, with significant potential benefits in terms of cost and robustness as compared to other highperformance gyro technologies.

  20. Laser Prevention of Earth Impact Disasters

    Science.gov (United States)

    Campbell, Jonathan W.; Howell, Joe (Technical Monitor)

    2002-01-01

    Today we are seeing the geological data base constantly expanding as new evidence from past impacts with the Earth are discovered and investigated. It is now commonly believed that a hypervelocity impact occurring approximately 65 million years ago in the Yucatan Peninsula area was the disaster responsible for the extinction of almost 70% of the species of life on Earth including of course the dinosaurs. What is sobering is that we believe now that this was just one of several such disasters and that some of the others caused extinctions to even a greater extent. Preventing collisions with the Earth by hypervelocity asteroids, meteoroids, and comets is the most important problem facing human civilization. While there are many global problems facing our planet including overpopulation, pollution, disease, and deforestation; none of these offer the potential of rapid, total extinction. Rapid is the operative word here in that many of the global problems we face may indeed, if not sufficiently addressed, pose a similar long-term threat. However, with the impact threat, a single, almost unpredictable event could lead to a chain reaction of disasters that would end everything mankind has worked to achieve over the centuries. Our chances of being hit are greater than our chance of winning the lottery. We now believe that while there are only about 2000-earth orbit crossing rocks great than 1 kilometer in diameter, there may be as many as 100,000 rocks in the 100 m size range. The 1 kilometer rocks are difficult to detect and even harder to track. The 100 m class ones are almost impossible to find with today's technology. Can anything be done about this fundamental existence question facing us? The answer is a resounding yes. By using an intelligent combination of Earth and space based sensors coupled with high-energy laser stations in orbit, we can deflect rocks from striking the Earth. This is accomplished by irradiating the surface of the rock with sufficiently intense

  1. Laser biostimulation (Ne-He and Ga-As) effects as compared to the conventional therapy in several pelvic inflammatory diseases

    Science.gov (United States)

    Antipa, Ciprian; Dona, Dumitru; Podoleanu, Adrian Gh.; Crisan, Nicolae; Constantinescu, Camelia

    1993-05-01

    We studied the effects of the very low-power Gallium-Arsenic infrared semiconductor laser and low-power Helium-Neon laser irradiation, single or in combination, compared to the placebo and conventional therapy on the recovery of 118 female patients from our hospital with the diagnosis of chronic pelvic inflammatory disorders. Laser biostimulation therapy proved to be significantly more efficient as compared with placebo or conventional therapy. The most efficient of all kinds of irradiations was the combination between He-Ne and Ga-As (laserpuncture and scanning). After laser treatments we didn't find any significant local genital changes both at the bimanual examination (except provoked pain), and at the echographical examination. Soft and very low-power laser therapy can be a useful alternative to the conventional treatments for pelvic inflammatory diseases.

  2. Laser therapy for prevention and treatment of pathologic excessive scars.

    Science.gov (United States)

    Jin, Rui; Huang, Xiaolu; Li, Hua; Yuan, Yuwen; Li, Bin; Cheng, Chen; Li, Qingfeng

    2013-12-01

    The management of hypertrophic scars and keloids remains a therapeutic challenge. Treatment regimens are currently based on clinical experience rather than substantiated evidence. Laser therapy is an emerging minimally invasive treatment that has recently gained attention. A meta-analysis was conducted to evaluate the effectiveness of various laser therapies. The pooled response rate, pooled standardized mean difference of Vancouver Scar Scale scores, scar height, erythema, and pliability were reported. Twenty-eight well-designed clinical trials with 919 patients were included in the meta-analysis. The overall response rate for laser therapy was 71 percent for scar prevention, 68 percent for hypertrophic scar treatment, and 72 percent for keloid treatment. The 585/595-nm pulsed-dye laser and 532-nm laser subgroups yielded the best responses among all laser systems. The pooled estimates of hypertrophic scar studies also showed that laser therapy reduced total Vancouver Scar Scale scores, scar height, and scar erythema of hypertrophic scars. Regression analyses of pulsed-dye laser therapy suggested that the optimal treatment interval is 5 to 6 weeks. In addition, the therapeutic effect of pulsed-dye laser therapy is better on patients with lower Fitzpatrick skin type scores. This study presents the first meta-analysis to confirm the efficacy and safety of laser therapy in hypertrophic scar management. The level of evidence for laser therapy as a keloid treatment is low. Further research is required to determine the mechanism of action for different laser systems and to examine the efficacy in quantifiable parameters, such as scar erythema, scar texture, degrees of symptom relief, recurrence rates, and adverse effects.

  3. Laser Doppler Vibrometer: Application of DOE/Taguchi Methodologies to Pyroshock Response Spectra

    Directory of Open Access Journals (Sweden)

    C. J. Litz

    1997-01-01

    Full Text Available Statistical methodologies were employed for measuring and analyzing the explosively induced transient responses of a flat steel plate excited with shock. The application of design of experiment methodology was made to structure and test a Taguchi L9(32 full factorial experimental matrix (which uses nine tests to study two factors, with each factor examined at three levels in which a helium-neon laser Doppler vibrometer and two piezocrystal accelerometers were used to monitor explosively induced vibrations ranging from 10 to 105 Hz on a 96 × 48 × 0.25 in. flat steel plate. Resulting conclusions were drawn indicating how these techniques aid in understanding the pyroshock phenomenon with respect to the effects and interrelationships of explosive-charge weight and location on the laser Doppler and contract accelerometer recording systems.

  4. [Laser speckle-based method for binocular vision recovery in diploptic treatment of concomitant strabismus].

    Science.gov (United States)

    Kashchenko, T P; Korniushina, T A; Bazarbaeva, A R; Magaramova, M D; Katsanashvili, R D

    2014-01-01

    to investigate the effectiveness of the method of "dissociation" for concomitant strabismus treatment, which involves laser speckles and polaroid separation of visual fields. A total of 40 patients with different types of concomitant strabismus and the average age of 9.8 years were enrolled. The treatment method implies the use of the Forbis device with polaroid separation of visual fields and low-energy helium-neon laser speckle patterns (green and red, 0.53 pm and 0.65 pm correspondingly). Binocular vision recovery was performed in the conditions of alternating exertion and relaxation of accommodation obtained through plus and minus spherical lenses. The method ensures an increase in the number of individuals capable of stereopsis from 31.2-44.4% (conventional treatment) to 54.4% as well as widening of the range of tolerated plus/minus spherical lenses, in which the binocular fusion is retained at the same degree of convergence.

  5. Induratio penis plastica (IPP) and laser: a review

    Science.gov (United States)

    Longo, Leonardo; Mancini, S.; Postiglione, M. G.

    2002-10-01

    The first employments of Laser therapy for I.P.P. came from back to more than twenty years ago. At the beginning it was employed only in the acute forms as analgesic laser laser was used also as anti-inflammatory following the doses of Low Level Laser Therapy. Than the science tried to use the laser effect remodelling phase of the scars, to make the fibrosis regrade in the chronic forms. Tunable laser in small optical fiber was used for ablation of calcified zones with very good results. For the slight forms were used diode laser 660 and 904 nm, alone ir coupling with CO2 laser with large spot. At first some Author used helium-Neon laser 632. Some of these lasers were combined wtih microiontophoresis and ultrasounds therapy in teh same treatment. Now we use 810 nm surgical diode laser in almost all induratio forms. The immediate results and follow up will be discussed. Thanks to these results we could conclude that IPP laser therapy can be effective in most of the clinic forms. Although the used procedure is subject to improvement.

  6. The use of low intensity laser radiation in the treatment of patients with closed traumatic brain injury consequences

    Directory of Open Access Journals (Sweden)

    Kolesov V.N.

    2016-06-01

    Full Text Available Objective: to determine the effectiveness of the use of low-intensity helium-neon laser radiation in patients with post-traumatic cerebral arachnoiditis. Material and Methods. We observed 164 patients with the effects of closed craniocerebral injuries of a various severity. Methods of percutaneous laser irradiation of blood in the projection of the common carotid artery at the level of IV cervical vertebra was carried out underthe supervision of the clinical evaluation of hemodynamic data survey methods. Results. Positive results of hemodynamic parameters of examination methods indicate regression of cerebral vasospasm and improving brain vascular reserve, which led to a decrease in cerebral and focal neurological symptoms. Conclusion. The method allows the use of this technique in these patients both in the hospital and at the outpatient stage.

  7. [Effects of laser radiation on the periodontium. An animal model approach. Effects of usual radiation dosage].

    Science.gov (United States)

    Noguerol Rodriguez, B; Alandez Chamorro, J; Cañizares Garcia, J; Campos Muñoz, A; Sicilia Felechosa, A

    1989-05-01

    Twenty four albino mice of forty days old were selected. Twelve forty days old albino mice were irradiated with a Helium-Neon laser source, dose of 10.50566 Jul/cm2. They were divided in two groups according to time of animal sacrifice (immediately after irradiation and ten days after). As control were used twelve mice using the same time as the experimental groups, but without radiation. T.E.M. ultrathin sections showed alteration only in the conjunctiva and in the bone tissues, but not in the epithelial tissue. The bone showed two osteocyte population according to their response to irradiation. The first population showed characteristic comparable with the controls, and the second showed alterations suggestive of a degenerative process. The connective tissue also showed two fibroblasts populations, the first showed signs of a big synthesizing activity, and the second, degenerative signs. The first fibroblast population appeared in the animals sacrificed immediately after irradiation.

  8. Ablation layers to prevent pitting in laser peening

    Science.gov (United States)

    Hackel, Lloyd A

    2016-08-09

    A hybrid ablation layer that comprises a separate under layer is applied to a material to prevent pitting resulting from laser peening. The underlayer adheres to the surface of the workpiece to be peened and does not have bubbles and voids that exceed an acceptable size. One or more overlayers are placed over and in contact with the underlayer. Any bubbles formed under the over layers are insulated from the surface to be peened. The process significantly reduces the incidence of pits on peened surfaces.

  9. Control of connective tissue metabolism by lasers: recent developments and future prospects

    Energy Technology Data Exchange (ETDEWEB)

    Abergel, R.P.; Meeker, C.A.; Lam, T.S.; Dwyer, R.M.; Lesavoy, M.A.; Uitto, J.

    1984-12-01

    Various laser modalities are currently in extensive use in dermatology and plastic surgery, particularly for treatment of vascular and pigmented lesions. A relatively new area of laser utilization involves the possible biologic effects of the lasers. In this overview, recent studies are summarized which indicate that lasers at specific wavelengths and energy densities modulate the connective tissue metabolism by skin fibroblasts both in vitro and in vivo. Specifically, the neodymium-yttrium-aluminum-garnet (Nd: YAG) laser was shown to selectively suppress collagen production both in fibroblast cultures and in normal skin in vivo, thus suggesting that this laser modality may be useful for the treatment of fibrotic conditions such as keloids and hypertrophic scars. Furthermore, two low-energy lasers, helium-neon (He-Ne) and gallium-arsenide (Ga-As), were shown to stimulate collagen production in human skin fibroblast cultures, suggesting that these lasers could be used for enhancement of wound healing processes. These experimental approaches illustrate the future possibilities for applying lasers for the modulation of various biologic functions of cells in tissues and attest to the potential role of lasers in the treatment of cutaneous disorders.

  10. Fall Prevention Shoes Using Camera-Based Line-Laser Obstacle Detection System

    OpenAIRE

    Tzung-Han Lin; Chi-Yun Yang; Wen-Pin Shih

    2017-01-01

    Fall prevention is an important issue particularly for the elderly. This paper proposes a camera-based line-laser obstacle detection system to prevent falls in the indoor environment. When obstacles are detected, the system will emit alarm messages to catch the attention of the user. Because the elderly spend a lot of their time at home, the proposed line-laser obstacle detection system is designed mainly for indoor applications. Our obstacle detection system casts a laser line, which passes ...

  11. Effect of low level laser therapy on neurovascular function of diabetic peripheral neuropathy

    Directory of Open Access Journals (Sweden)

    Abeer A. Yamany

    2012-01-01

    Full Text Available Diabetic neuropathy is the most common complication and greatest source of morbidity and mortality in diabetic patients. Thirty male and female patients with painful diabetic neuropathy and abnormal results from nerve conduction studies participated in this study. Their ages ranged from 45 to 60 years with a mean of 52.1 ± SD 4.7 years. Patients were randomly assigned into two equal groups of 15, an active laser group (laser group and a placebo laser group (control group. The laser group received scanning helium neon (He–Ne infrared laser with wavelength 850 nm and density of 5.7 J/cm2, applied to the lumbosacral area and the plantar surface of the foot for 15 min each site/session three times per week for four weeks (i.e. 12 sessions. Pain intensity via visual analogue scale, bilateral peroneal motor nerves, sural sensory nerves conduction velocity and amplitude and foot skin microcirculation, were measured pre- and post-treatment for both groups. Pain was significantly decreased (p ⩽ 0.05 and electrophysiological parameters and foot skin microcirculation were significantly improved (p ⩽ 0.05 in the laser group, while no significant change was obtained in the control group. Low level laser therapy within the applied parameters and technique could be an effective therapeutic modality in reducing pain and improving neurovascular function in patients with diabetic polyneuropathy.

  12. Evaluation of laser therapy and routine treatment modalities in the management of myofascial pain dysfunction syndrome

    Directory of Open Access Journals (Sweden)

    Smriti B Jagdhari

    2015-01-01

    Full Text Available Objective: To evaluate the efficacy of laser as a monotherapy and in combination with exercise therapy in comparison to only exercise in the treatment of Myofascial Pain Dysfunction Syndrome (MPDS or Temporomandibular Myofascial Pain. Materials and Methods: A total of 60 patients with MPDS were included in the study and were randomly divided into three groups: exercise, laser, and the combination of both (exercise and laser. Results: Significant reduction in pain at rest and pain on movement was observed with all three types of treatment modalities. Pain reduction was more in those patients who received combination of exercise and laser therapy. Similarly, decrease in the muscle tenderness was more when combination of exercise and laser therapy was used. Conclusion: The ideal therapy should be fast, cheap, and have a long-term effect. Laser (Helium Neon as monotherapy or in combination with exercise had shown promising results and can be used as an effective treatment modality for the treatment of MPDS.

  13. Low level laser therapy on experimental myopathy

    Science.gov (United States)

    Dávila, Soledad; Vignola, María Belén; Cremonezzi, David; Simes, Juan C.; Soriano, Fernando; Campana, Vilma R.

    2011-01-01

    Purpose: The aim of the present work was to study the effect of Helium-Neon (HeNe) and Gallium Arsenide (GaAs) laser upon nitric oxide (NO) plasma levels, an inflammatory biomarker associated with oxidative stress, in rats with experimental myopathy. These were evaluated through histological assessment. Materials and Methods: The groups studied were: (A) control (intact rats that received LLLT sham exposures), (B) rats with myopathy and sacrificed at 24 h later, (C) rats with myopathy and sacrificed 8 days later, (D) rats with myopathy and treated with HeNe laser, (E) rats with myopathy and treated with GaAs laser, (F) intact rats treated with HeNe laser and (G) intact rats treated with GaAs laser. Myopathy was induced by injecting 50μl of 1% carrageenan λ (type IV) in the left gastrocnemius muscle. Low Level Laser Therapy (LLLT) was applied with 9.5 J.cm−2 daily for 10 consecutive days with each laser. The determination of the NO was made by spectrophotometry. The muscles were stained with Hematoxylin-Eosin and examined by optic microscopy. Quantitative variables were statistically analyzed by the Fisher test, and categorical by applying Pearson's Chi Squared test at p <0.05 for all cases. Results: In groups B and C, NO was significantly increased compared to groups A, D, E, F and G (p<0.05). In group C, the percentage of area with inflammatory infiltration was significantly increased compared to the other groups (p<0.001). Conclusions: LLLT decreased plasma levels of NO in rats with experimental myopathies and significant muscle recovery. PMID:24155539

  14. Changes in the germination process and growth of pea in effect of laser seed irradiation

    Science.gov (United States)

    Podleśna, Anna; Gładyszewska, Bożena; Podleśny, Janusz; Zgrajka, Wojciech

    2015-10-01

    The aim of this study was to determine the effect of pre-sowing helium-neon (He-Ne) laser irradiation of pea seeds on changes in seed biochemical processes, germination rate, seedling emergence, growth rate, and yield. The first experimental factor was exposure to laser radiation: D0 - no irradiation, D3 - three exposures, D5 - five exposures, and the harvest dates were the second factor. Pre-sowing treatment of pea seeds with He-Ne laser light increased the concentrations of amylolytic enzymes and the content of indole-3-acetic acid (IAA) in pea seeds and seedlings. The exposure of seeds to He-Ne laser light improved the germination rate and uniformity and modified growth stages, which caused acceleration of flowering and ripening of pea plants. Laser light stimulation improved the morphological characteristics of plants by increasing plant height and leaf surface area. Irradiation improved the yield of vegetative and reproductive organs of pea, although the effects varied at the different growth stages. The increase in the seed yield resulted from a higher number of pods and seeds per plant, whereas no significant changes were observed in the number of seeds per pod. Both radiation doses exerted similarly stimulating effects on pea growth, development, and yield.

  15. Experimental AMO physics in undergraduate optics and lasers courses

    Science.gov (United States)

    Hoyt, Chad

    2017-04-01

    This talk will describe experimental AMO research projects in undergraduate Lasers and Optics courses at Bethel University. The courses, which include a comprehensive lecture portion, are built on open-ended projects that have a novel aspect. Classes begin with four weeks of small student groups rotating between several standard laser and optics laboratory exercises. These may include, for example, alignment and characterization of a helium neon laser and measurements with a Michelson interferometer or a scanning Fabry-Pérot optical cavity. During the following seven weeks of the course, student groups (2-4 people) choose and pursue research questions in the lab. Their work culminates in a group manuscript and a twenty-minute presentation to the class. Projects in the spring, 2016 Optics course included experiments with ultracold lithium atoms in a magneto-optical trap, a prototype, portable, mode-locked erbium fiber laser, a home-built fiber laser frequency comb, double-slit imaging with single photons, and digital holographic tweezers (led by Nathan Lindquist). Projects in the spring, 2015 Lasers course included ultrafast optics with a mode-locked erbium fiber laser, quantum optics, surface plasmon lasers (led by Nathan Lindquist) and a low-cost, near-infrared spectrometer. Several of these projects are related to larger scale, funded research in the physics department. The format and experience in Lasers and Optics is representative of other upper-level courses at Bethel, including Fluid Mechanics and Computer Methods. A physics education research group from the University of Colorado evaluated the spring, 2015 Lasers and 2016 Optics courses. They focused on student experimental attitudes and measurements of student project ownership.

  16. Láser helio-neón combinado con clorhexidina al 0,2 %.: Efectos clínicos y microbiológicos en el tratamiento de la gingivitis crónica Helium-neon laser combined with 0.2% chlorhexidine: Clinical and microbiological effects in the treatment of chronic gingivitis.

    OpenAIRE

    Tatiana Peña Ruiz; Ariel Delgado Ramos; Ariadna González Lorenzo

    2007-01-01

    La gingivitis crónica constituye una de las formas más frecuentes de enfermedad periodontal, caracterizada por la inflamación crónica de la encías, tumefacción, enrojecimiento y sangramiento. Su principal factor de riesgo lo constituye la microbiota del surco gingival, que resulta necesario, pero no suficiente para desencadenarla. Se realizó un ensayo clínico-terapéutico fase II, controlado, aleatorizado y a simple ciegas, para evaluar los efectos clínicos y microbiológicos del tratamiento co...

  17. Oral mucositis prevention and management by therapeutic laser in head and neck cancers.

    Science.gov (United States)

    Fekrazad, Reza; Chiniforush, Nasim

    2014-01-01

    Oral mucositis is considered a severe complication in cancer patients receiving radiotherapy or chemotherapy for head and neck cancer. The aim of this review study was to assess the effect of low level laser therapy for prevention and management of oral mucositis in cancer patients. The electronic databases searched included Pubmed, ISI Web of Knowledge and Google scholar with keywords as "oral mucositis", "low level laser therapy" from 2000 to 2013. The results of most studies showed that photobiomodulation (PBM) reduced the severity of mucositis. Also, it can delay the appearance of severe mucositis. Low level laser therapy is a safe approach for management and prevention of oral mucositis.

  18. Testing relativity again, laser, laser, laser, laser

    NARCIS (Netherlands)

    Einstein, A.

    2015-01-01

    laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser, laser,

  19. Low power laser irradiation stimulates cell proliferation via proliferating cell nuclear antigen and Ki-67 expression during tissue repair

    Science.gov (United States)

    Prabhu, Vijendra; Rao, Bola Sadashiva Satish; Mahato, Krishna Kishore

    2015-03-01

    Low power laser irradiation (LPLI) is becoming an increasingly popular and fast growing therapeutic modality in dermatology to treat various ailments without any reported side effects. In the present study an attempt was made to investigate the proliferative potential of red laser light during tissue repair in Swiss albino mice. To this end, full thickness excisional wounds of diameter 15 mm created on mice were exposed to single dose of Helium-Neon laser (632.8 nm; 7 mW; 4.02 mWcm-2; Linear polarization) at 2 Jcm-2 and 10 Jcm-2 along with un-illuminated controls. The granulation tissues from all the respective experimental groups were harvested on day 10 post-wounding following euthanization. Subsequently, tissue regeneration potential of these laser doses under study were evaluated by monitoring proliferating cell nuclear antigen and Ki-67 following the laser treatment and comparing it with the un-illuminated controls. The percentages of Ki-67 or PCNA positive cells were determined by counting positive nuclei (Ki-67/PCNA) and total nuclei in five random fields per tissue sections. Animal wounds treated with single exposure of the 2 Jcm-2 indicated significant elevation in PCNA (Pregeneration.

  20. [Hemoaggregation dynamics in human-operator during percutaneous laser blood irradiation].

    Science.gov (United States)

    Subbotina, L A; Radchenko, S N; Golovkina, O L; Bubeev, Iu A

    2009-01-01

    The experiment with essentially healthy male subjects no older than 50 involved functional load testing and irradiation by a low-energy helium-neon laser according to the standard therapeutic regimen (0.2 ml/V/ 30 min/10 sessions). Biomedical evaluation of hemoaggregation was made by 30 parameters of a multifunctional diagnostic system characterizing three blood aggregation levels: rheological (biophysical), coagulolytic (biochemical) and system (mathematical). The investigation resulted in delineation of a single-vector hypodynamic transformation of biophysical and biochemical modules, i.e. decrease in the rheological and coagulative potential mediated by a moderate platelets disaggregation (24.6%) and hyperactivation of plasmin proferments in euglobulin fraction (126.76 %). Added sessions of percutaneous laser irradiation of blood were shown to induce a medium imbalance of biophysical and biochemical hemoaggregation. At the same time, low-energy laser did not modulate significantly the general functional state of human operator as the rheological and coagulative protective potential of organism remained reasonably high (88.89 and 87.5 %, respectively).

  1. A laser scanner for imaging fluorophore labeled molecules in electrophoretic gels

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, D.J.; Sutherland, J.C. [Brookhaven National Lab., Upton, NY (United States). Biology Dept.

    1995-08-01

    A laser scanner for imaging electrophoretic gels was constructed and tested. The scanner incorporates a green helium-neon (HeNe) laser (543.5nm wavelength) and can achieve a spatial resolution of 19{micro}m. The instrument can function in two modes : snap-shot and finish-line. In snapshot mode, all samples are electrophoresed for the same time and the gel is scanned after completion of electrophoresis, while in finish-line mode, fluorophore labeled samples are electrophoresed for a constant distance and the image is formed as the samples pass under the detector. The resolving power of the finish-line mode of imaging is found to be greater than that of the snapshot mode of imaging. This laser scanner is also compared with a Charge Coupled Device (CCD) camera and in terms of resolving power is found to be superior. Sensitivity of the instrument is presented in terms of the minimum amount of DNA that can be detected verses its molecular length.

  2. Low-energy laser irradiation increases endothelial cell proliferation, migration, and eNOS gene expression possibly via PI3K signal pathway.

    Science.gov (United States)

    Chen, Chung-Huang; Hung, Huey-Shan; Hsu, Shan-Hui

    2008-01-01

    The purpose of this study, therefore, was to determine the mechanisms by which low-energy laser irradiation (LELI) may exert some of its angiogenic effects via the PI3 kinase/eNOS signaling pathway and induce endothelial cell migration and neovascularization, an important and necessary part of wound healing. The possible molecular mechanism of helium-neon (He-Ne) laser irradiation on endothelial cells was proposed. He-Ne laser at 632.5 nm was used to stimulate human umbilical vein endothelial cell (HUVEC), and its effect on cell proliferation, nitric oxide secretion, and cell migration was determined. Irradiation enhanced endothelial nitric oxidase synthase (eNOS) protein expression, and irradiation of less than 0.26 J/cm(2) enhanced eNOS gene expression in HUVEC. The cell migration ability was promoted for HUVEC irradiated with 0.26 J/cm(2). This agreed with the vinculin protein expression induced by irradiation. In addition, the angiogenesis was promoted. The induced eNOS expression was inhibited by LY294002, indicating that the effect of laser on EC could be attributed to the up-regulation of eNOS expression through PI3K pathway at the cellular and molecular levels as a result of the He-Ne laser. The study has shown that LELI increased endothelial cell proliferation, migration, NO secretion, and identified that activation of PI3K/Akt pathway was a critical step for the elevated for eNOS expression upon LELI.

  3. CO2 Laser (10.6 microm) parameters for caries prevention in dental enamel.

    Science.gov (United States)

    Esteves-Oliveira, M; Zezell, D M; Meister, J; Franzen, R; Stanzel, S; Lampert, F; Eduardo, C P; Apel, C

    2009-01-01

    Although CO(2) laser irradiation can decrease enamel demineralisation, it has still not been clarified which laser wavelength and which irradiation conditions represent the optimum parameters for application as preventive treatment. The aim of the present explorative study was to find low-fluence CO(2) laser (lambda = 10.6 microm) parameters resulting in a maximum caries-preventive effect with the least thermal damage. Different laser parameters were systematically evaluated in 3 steps. In the first experiment, 5 fluences of 0.1, 0.3, 0.4, 0.5 and 0.6 J/cm(2), combined with high repetition rates and 10 micros pulse duration, were chosen for the experiments. In a second experiment, the influence of different pulse durations (5, 10, 20, 30 and 50 micros) on the demineralisation of dental enamel was assessed. Finally, 3 different irradiation times (2, 5 and 9 s) were tested in a third experiment. In total, 276 bovine enamel blocks were used for the experiments. An 8-day pH-cycling regime was performed after the laser treatment. Demineralisation was assessed by lesion depth measurements with a polarised light microscope, and morphological changes were assessed with a scanning electron microscope. Irradiation with 0.3 J/cm(2), 5 micros, 226 Hz for 9 s (2,036 overlapping pulses) increased caries resistance by up to 81% compared to the control and was even significantly better than fluoride application (25%, p laser irradiation. (c) 2009 S. Karger AG, Basel.

  4. Low-level laser therapy: a useful technique for enhancing the proliferation of various cultured cells.

    Science.gov (United States)

    AlGhamdi, Khalid M; Kumar, Ashok; Moussa, Noura A

    2012-01-01

    The aim of this work is to review the available literature on the details of low-level laser therapy (LLLT) use for the enhancement of the proliferation of various cultured cell lines including stem cells. A cell culture is one of the most useful techniques in science, particularly in the production of viral vaccines and hybrid cell lines. However, the growth rate of some of the much-needed mammalian cells is slow. LLLT can enhance the proliferation rate of various cell lines. Literature review from 1923 to 2010. By investigating the outcome of LLLT on cell cultures, many articles report that it produces higher rates of ATP, RNA, and DNA synthesis in stem cells and other cell lines. Thus, LLLT improves the proliferation of the cells without causing any cytotoxic effects. Mainly, helium neon and gallium-aluminum-arsenide (Ga-Al-As) lasers are used for LLLT on cultured cells. The results of LLLT also vary according to the applied energy density and wavelengths to which the target cells are subjected. This review suggests that an energy density value of 0.5 to 4.0 J/cm(2) and a visible spectrum ranging from 600 to 700 nm of LLLT are very helpful in enhancing the proliferation rate of various cell lines. With the appropriate use of LLLT, the proliferation rate of cultured cells, including stem cells, can be increased, which would be very useful in tissue engineering and regenerative medicine.

  5. Inducing myoblast re-entry into the cell cycle: a potential mechanism for laser-enhanced skeletal muscle regeneration

    Science.gov (United States)

    Liu, T.; Fang, Y.; Zhang, C. P.; Chen, P.; Wang, C. Z.; Kang, H. X.; Shen, B. J.; Liang, J.; Fu, X. B.

    2014-09-01

    This study investigated the effect of low-level laser irradiation (LLLI) on the cell cycle and proliferative activity of cultured myoblasts, and sought to elucidate the possible cellular mechanism by which LLLI promotes the regeneration of skeletal muscle in vivo. Primary myoblasts isolated from rat hindlegs were irradiated with helium-neon laser light at different energy densities. Distributions of cell-cycle subpopulations and the expression of cell-cycle regulatory proteins in myoblasts were assessed using flow cytometric analysis and western blot assay. It was found that laser irradiation stimulated cell-cycle entry; induced the expression of cyclin A and cyclin D; and increased cell proliferation index and bromodeoxyuridine incorporation as compared to the unirradiated control cells, indicating LLLI augmented the number of proliferative myoblasts in the S phase and G2/M phase of the cell cycle. These results suggest that LLLI at certain fluxes and wavelengths could activate quiescent myoblasts, leading to cell division and facilitating new myofiber formation. This could contribute to the improvement of skeletal muscle regeneration following trauma and myopathic diseases.

  6. Laser Metrology for an Optical-Path-Length Modulator

    Science.gov (United States)

    Gursel, Yekta

    2005-01-01

    Laser gauges have been developed to satisfy requirements specific to monitoring the amplitude of the motion of an optical-path-length modulator that is part of an astronomical interferometer. The modulator includes a corner-cube retroreflector driven by an electromagnetic actuator. During operation of the astronomical interferometer, the electromagnet is excited to produce linear reciprocating motion of the corner-cube retroreflector at an amplitude of 2 to 4 mm at a frequency of 250, 750, or 1,250 Hz. Attached to the corner-cube retroreflector is a small pick-off mirror. To suppress vibrations, a counterweight having a mass equal to that of the corner-cube retroreflector and pick-off mirror is mounted on another electromagnetic actuator that is excited in opposite phase. Each gauge is required to measure the amplitude of the motion of the pick-off mirror, assuming that the motions of the pick-off mirror and the corner-cube retroreflector are identical, so as to measure the amplitude of motion of the corner- cube retroreflector to within an error of the order of picometers at each excitation frequency. Each gauge is a polarization-insensitive heterodyne interferometer that includes matched collimators, beam separators, and photodiodes (see figure). The light needed for operation of the gauge comprises two pairs of laser beams, the beams in each pair being separated by a beat frequency of 80 kHz. The laser beams are generated by an apparatus, denoted the heterodyne plate, that includes stabilized helium-neon lasers, acousto-optical modulators, and associated optical and electronic subsystems. The laser beams are coupled from the heterodyne plate to the collimators via optical fibers.

  7. Development of fiber-delivered laser peening system to prevent stress corrosion cracking of reactor components

    Energy Technology Data Exchange (ETDEWEB)

    Sano, Y.; Kimura, M.; Yoda, M.; Mukai, N.; Sato, K.; Uehara, T.; Ito, T.; Shimamura, M.; Sudo, A.; Suezono, N. [Toshiba Corp., Yokohama (Japan)

    2001-07-01

    The authors have developed a system to deliver water-penetrable intense laser pulses of frequency-doubled Nd:YAG laser through optical fiber. The system is capable of improving a residual stress on water immersed metal material remotely, which is effective to prevent the initiation of stress corrosion cracking (SCC) of reactor components. Experimental results showed that a compressive residual stress with enough amplitude and depth was built in the surface layer of type 304 stainless steel (SUS304) by irradiating laser pulses through optical fiber with diameter of 1 mm. A prototype peening head with miniaturized dimensions of 88 mm x 46 mm x 25 mm was assembled to con-firm the accessibility to the heat affected zone (HAZ) along weld lines of a reactor core shroud. The accessibility was significantly improved owing to the flexible optical fiber and the miniaturized peening head. The fiber delivered system opens up the possibility of new applications of laser peening. (author)

  8. Oral Mucositis Prevention and Management by Therapeutic Laser in Head and Neck Cancers

    OpenAIRE

    Fekrazad, Reza; Chiniforush, Nasim

    2014-01-01

    Introduction: Oral mucositis is considered a severe complication in cancer patients receiving radiotherapy or chemotherapy for head and neck cancer. The aim of this review study was to assess the effect of low level laser therapy for prevention and management of oral mucositis in cancer patients.

  9. Recommendations concerning the prevention of radiation-induced health hazards through the application of soft and MID lasers

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    The Federal Health Office (BGA) recommends observation of the following practical hints: The application of soft lasers or MID lasers for cosmetic treatment or acupuncture represents a danger to the eye. Instructions for use of laser equipment have to indicate this danger. Appropriate use of the equipment will prevent damage. Any person applying soft lasers or MID lasers for treatment of customers or patients near the eye are required to give proof of a special training assuring appropriate handling, and of instructions in laser radiation protection.

  10. Nd:YAG laser in occlusal caries prevention of primary teeth: a randomized clinical trial.

    Science.gov (United States)

    Raucci-Neto, Walter; de Castro-Raucci, Larissa Moreira Spinola; Lepri, Cesar Penazzo; Faraoni-Romano, Juliana Jendiroba; Gomes da Silva, Jaciara Miranda; Palma-Dibb, Regina Guenka

    2015-02-01

    Dental caries is still the most prevalent chronic disease affecting human populations. Among the preventive treatments performed, it has been reported that laser irradiation combined with topical fluoride can induce an even greater increase in enamel caries resistance. The aim of this study was to evaluate the Nd:YAG laser, with or without fluoride, in occlusal caries prevention of the primary dentition. A double-blind split-mouth study design was used. Fifty-two children with high caries risk (7.6 ± 1.4 years) were selected and received the following: G1--the first molar was a negative control, and the second received a resin sealant; G2--the first molar was a negative control, and the second received laser irradiation (50 mJ, 10 Hz, 0.5 W); G3--the first molar received only acidulate phosphate fluoride (APF), and the second received APF + laser; G4--fisrt molar received only fluoride varnish, and the second received fluoride varnish + laser. Patients were followed up to 12 months to evaluate the presence of white-spot lesions and/or caries cavities by three calibrated observers. Thirty-five patients completed the study. Significant differences were found between the treatment and control groups (p laser-alone and resin sealant resulted in statistically lower caries formation than the negative control group (p laser irradiation in primary teeth effectively prevented occlusal caries in pits and fissures when used alone with lower energy over a 1-year period.

  11. Cooling prevents induction of corneal damage by argon laser peripheral iridotomy.

    Science.gov (United States)

    Kataoka, Takuya; Zako, Masahiro; Takeyama, Masayuki; Ohno-Jinno, Akiko; Sugenoya, Junichi; Iwaki, Masayoshi

    2007-01-01

    There are many reports of corneal complications caused by argon laser peripheral iridotomy. In this study, we investigated whether cooling the anterior ocular segment during laser iridotomy prevented corneal damage. A space for cooling the anterior ocular segment by perfusion with ice-cold water was made between the cornea and a contact lens. Dutch pigmented rabbits were excessively irradiated by an argon green laser, aiming at the peripheral iris. We used a contact lens without a cooling system as a control. Temperature in the anterior chamber and intraocular pressure were also monitored throughout the experiment. During laser treatment, the temperature without the cooling system rose to a maximum of 44.5 degrees C in the anterior chamber, whereas use of the cooling system consistently kept this temperature at 11.1 degrees -16.1 degrees C. Although most eyes treated without cooling showed corneal damage, damage was seen in only a few or in no eyes cooled during laser treatment. Argon laser treatment using contact lenses with a cooling system drastically reduced the corneal damage induced by argon laser peripheral iridotomy. This technique may be acceptable for clinical use, considering its technical simplicity and low incidence of treatment-related complications.

  12. Femtosecond laser induced surface modification for prevention of bacterial adhesion on 45S5 bioactive glass

    Science.gov (United States)

    Shaikh, Shazia; Singh, Deepti; Subramanian, Mahesh; Kedia, Sunita; Singh, Anil Kumar; Singh, Kulwant; Gupta, Nidhi; Sinha, Sucharita

    2018-02-01

    Bacterial attachment and biofilm formation on implant surface has been a major concern in hospital and industrial environment. Prevention of bacterial infections of implant surface through surface treatment could be a potential solution and hence this has become a key area of research. In the present study, the antibacterial and biocompatible properties of femtosecond laser surface treated 45S5 bioactive glass (BG) have been investigated. Adhesion and sustainability of both gram positive S. aureus and gram negative P.aeruginosa and E. coli nosocomial bacteria on untreated and laser treated BG samples has been explored. An imprint method has been used to visualize the growth of bacteria on the sample surface. We observed complete bacterial rejection potentially reducing risk of biofilm formation on laser treated surface. This was correlated with surface roughness, wettability and change in surface chemical composition of the samples before and after laser treatment. Biocompatibility of the laser treated BG was demonstrated by studying the anchoring and growth of human cervix cell line INT407. Our results demonstrate that, laser surface modification of BG enables enhanced bacterial rejection without affecting its biocompatibility towards growth of human cells on it. These results open a significantly potential approach towards use of laser in successfully imparting desirable characteristics to BG based bio-implants and devices.

  13. Is it possible to prevent morbidity on post cardiovascular surgery applying low level laser therapy?

    Science.gov (United States)

    Pinto, Nathali C.; Baptista, Ivany Machado d. C.; Pereira, Mara Helena C.; Serrão, Nelson F.; Pomerantzeff, Pablo M. A.; Chavantes, Maria Cristina

    2014-03-01

    Background and Objective: Complications following cardiovascular surgery incision are common in mediastinitis and wound dehiscence form, a 47% mortality rate remaining. Low Level Laser Therapy (LLLT) has been employed mainly to its effectiveness analgesic and anti-inflammatory actions, aiding the tissue repair process. The aim of this study was to evaluate infrared LLLT onto surgical incision in patients submitted to cardiovascular surgery. Materials and Methods: 40 patients were divided in two groups: Placebo Group (G1) - conventional therapy + "Laser pointer" and Laser Group (G2) - conventional therapy + Infrared Laser irradiation on surgical incision. Diode Laser was employed, C.W. mode, around the surgical wound bed, on immediate Post Operative (PO), 1st PO and 3rd PO with the following parameters: wavelength (λ): 830nm, P=35mW, E=0,75J. Results: G2 didn't present any complication and 5% of patients in G1 developed incision dehiscence and infection. On 7thPO, still a large amount of G1 patients showed pain and unquestionable inflammatory signs surrounding the surgical wound, when compared to G2. Besides, hospital stay in Laser Group was 2 times shorter than in Placebo Group (p-value=0.001). Conclusion: Infrared Laser denoted to be safe and exceptionally valuable tools in preventing morbidities on post cardiovascular surgeries.

  14. The combined use of Er,Cr:YSGG laser and fluoride to prevent root dentin demineralization

    Directory of Open Access Journals (Sweden)

    Vinícius Rangel GERALDO-MARTINS

    2014-10-01

    Full Text Available The use of erbium lasers to prevent caries in enamel has shown positive results. However, it is not known if Er,Cr:YSGG laser can also be used to increase acid resistance of root dentine, which is another dental tissue susceptible to the action of cariogenic bacteria. Objective: To analyze the effects of the Er,Cr:YSGG laser (λ=2.78 μm, 20 Hz irradiation associated with 2% neutral sodium fluoride (NaF to prevent root dentin demineralization. Material and Methods: One hundred human root dentin samples were divided into 10 groups (G and treated as follows: G1: no treatment; G2: NaF; G3: laser (4.64 J/cm2 with water cooling (WC=5.4 mL/min; G4: laser (4.64 J/cm2 without WC; G5: laser (8.92 J/cm2 with WC; G6: laser (8.92 J/cm2 without WC; G7: laser (4.64 J/cm2 with WC and NaF; G8: laser (4.64 J/cm2 without WC and NaF; G9: laser (8.92 J/cm2 with WC and NaF; G10: laser (8.92 J/cm2 without WC and NaF. The NaF gel was applied alone or after 4 min of irradiation. After 14 days of acid challenge, the samples were sectioned and the Knoop microhardness (KHN test was done at different depths (30, 60, 90 and 120 μm from the outer dentin surface. Data were analyzed by one-way ANOVA and Fisher’s test (α=5%. Results: The results showed that G8 and G10 presented higher KHN than the G1 for the depths of 30 and 60 μm, indicating an increase of the acid resistance of the dentin in up to 35% (p<0.05. Conclusions: The use of Er,Cr:YSGG laser irradiation at 4.64 J/ cm2 and 8.92 J/cm2 without water cooling and associated with 2% NaF can increase the acid resistance of human root dentin.

  15. Stimulative Effects of Low Intensity He-Ne Laser Irradiation on the Proliferative Potential and Cell-Cycle Progression of Myoblasts in Culture

    Directory of Open Access Journals (Sweden)

    Cui-Ping Zhang

    2014-01-01

    Full Text Available Low intensity laser irradiation (LILI was found to promote the regeneration of skeletal muscle in vivo but the cellular mechanisms are not fully understood. Myoblasts, normally quiescent and inactivated in adult skeletal muscle, are a type of myogenic progenitor cells and considered as the major candidates responsible for muscle regeneration. The aim of the present study was to study the effect of LILI on the growth potential and cell-cycle progression of the cultured myoblasts. Primary myoblasts isolated from rat hind legs were cultured in nutrient-deficient medium for 36 hours and then irradiated by helium-neon laser at a certain energy density. Immunohistochemical and flow cytometric analysis revealed that laser irradiation could increase the expression of cellular proliferation marker and the amount of cell subpopulations in the proliferative phase as compared with the nonirradiated control group. Meanwhile, the expressions of cell-cycle regulatory proteins in the laser-treated myoblasts were markedly upregulated as compared to the unirradiated cells, indicating that LILI could promote the reentry of quiescent myoblasts into the cell division cycle. These results suggest that LILI at certain fluences could promote their proliferation, thus contributing to the skeletal muscle regeneration following trauma and myopathic diseases.

  16. Effect of Low Power Laser Irradiation on the Ability of Cell Growth and Myogenic Differentiation of Myoblasts Cultured In Vitro

    Directory of Open Access Journals (Sweden)

    Cui-Ping Zhang

    2014-01-01

    Full Text Available As a therapeutic modality, low power laser irradiation (LPLI has been used clinically in the treatment of skeletal muscle injuries and other myopathic conditions, but the cellular and molecular mechanisms attributed to this therapy were still unclear. Myoblasts are a type of myogenic stem cells quiescence in mature skeletal muscle fibers and are considered as the source cells during the regenerating process. The purpose of this paper was to investigate the effects of LPLI on the proliferation and myogenic differentiation of the cultured myoblasts and to find out the major candidates responsible for LPLI-induced muscle regeneration in vivo. In this study, primary rat myoblasts were exposed to helium-neon (He-Ne laser. Cell proliferation, differentiation, and the cellular responses to LPLI were monitored by using morphological observation and molecular biological methods. It was found that LPLI at a certain fluence could increase the cell growth potential for myoblasts and further induce more cells entering into S phase of the mitotic cycle as indicated by high levels of bromodeoxyuridine (BrdU incorporation, while at the same time inhibiting their in vitro differentiation and decreasing the expression of myogenic regulatory genes to a certain extent. Taken together, these results provide experimental evidence for the clinical applications of LPLI in regenerating skeletal muscle.

  17. Frequency stability measurement of a transfer-cavity-stabilized diode laser by using an optical frequency comb

    Science.gov (United States)

    Uetake, S.; Matsubara, K.; Ito, H.; Hayasaka, K.; Hosokawa, M.

    2009-10-01

    We report results of frequency stability measurements of an extended cavity diode laser (ECDL) whose frequency is stabilized by a non-evacuated scanning transfer cavity. The transfer cavity is locked to a commercial frequency stabilized helium-neon laser. Frequency stability is measured by use of an optical frequency comb. The environmental perturbations (variations of temperature, air pressure, and humidity) are also simultaneously measured. The observed frequency drift of the ECDL is well explained by environmental perturbations. An atmospheric pressure variation, which is difficult to control with a non-evacuated cavity, is mainly affected to the frequency stability. Thus we put the cavity into a simple O-ring sealed (non-evacuated) tube. With this simple O-ring sealed tube, the frequency drift is reduced by a factor of 3, and the Allan variance reaches a value of 2.4×10-10, corresponds to the frequency stability of 83 kHz, at the average time of 3000 s. Since the actual frequency drift is well estimated by simultaneous measurement of the ambient temperature, pressure, and humidity, a feed-forward compensation of frequency drifts is also feasible in order to achieve a higher frequency stability with a simple non-evacuated transfer cavity.

  18. Procedures for Precise Determination of Thermal Radiation Properties November 1962 to October 1963

    National Research Council Canada - National Science Library

    Richmond, Joseph

    1964-01-01

    The preliminary design of an intergrating-sphere reflectometer, utilizing a helium-neon continuous-wave gas laser as the source, for measuring the reflectance of specimens at high temperature, was completed...

  19. Hot cracking during laser welding of steel: influence of the welding parameters and prevention of cracks

    Science.gov (United States)

    Schaefer, Marcel; Kessler, Steffen; Scheible, Philipp; Speker, Nicolai; Harrer, Thomas

    2017-02-01

    In continuous wave keyhole-mode laser welding of high strength steel alloys hot cracking can occur. The hot crack susceptibility depends on the mutual interaction of several factors like the welding parameters, the alloy composition and the weld fixturing. In this paper we focus on the influence of the welding parameters and investigate the dependency of the laser power, the welding speed and the laser wavelength on the crack formation. X-ray images are used to visualize the hot crack patterns, which exhibit a pronounced periodicity. To influence the hot crack formation, the incident energy input into the process was adapted. For specific welding parameters, we show exemplarily the prevention of hot cracking by the use of a twin-spot optics.

  20. Soft-tissue injuries from sports activities and traffic accidents--treatment with low-level laser therapy: a multicenter double-blind placebo-controlled clinical study on 132 patients

    Science.gov (United States)

    Simunovic, Zlatko; Trobonjaca, Tatjana

    2000-06-01

    The aim of current multicenter clinical study was to assess the efficacy of low energy-level laser therapy (LLLT) in the treatment of soft tissue injuries compared to the placebo and classical phyiotherapeutic procedures. This clinical study was conducted in two centers located in Locarno, Switzerland and Opatija, Croatia. Two types of irradiation techniques were used: (1) direct, skin contact technique for treatment of trigger points where IR diode laser 830 nm continuous wave was applied; and (2) scanning technique for irradiation of larger surface area with use of Helium Neon laser 632.8 nm combined with IR diode laser 904 nm pulsed wave. Results were evaluated according to clinical parameters like: hematoma, swelling, heat, pan and loss of function. The findings were statistically analyzed via chi- square test. Results have demonstrated that the recovery process was accelerated in 85 percent of patients treated with LLLT compared to the control group of patients. The results and advantages obtained proved once again the efficacy of LLLT as a new and successful way to treat soft tissue injuries.

  1. Low-level laser for prevention and therapy of oral mucositis induced by chemotherapy or radiotherapy.

    Science.gov (United States)

    Genot, Marie-Thérèse; Klastersky, Jean

    2005-05-01

    Oral mucositis is a common morbid condition associated with chemotherapy or radiotherapy for which there is no standard prophylaxis or treatment. There is increasing evidence that the use of low-level laser can reduced the severity of mucositis associated with chemotherapy or radiation therapy. The purpose of this review is to examine the available evidence for it. For most approaches commonly used to prevent or treat chemotherapy-associated or radiotherapy-associated oral mucositis, a recent panel of experts could not find sufficient levels of evidence to recommend or suggest their use. As for low-level laser therapy, the results are difficult to assess and compare because of interoperator variability and because clinical trials are difficult to conduct in that field. Nevertheless, there is accumulating evidence in support of low-level laser therapy. On the basis of literature data, it is reasonable to conclude that the evidence that low-level laser therapy may be useful in decreasing the severity of chemotherapy-associated or radiotherapy-associated mucositis is substantial, even though there have been few controlled studies in the field of prevention.

  2. Fall Prevention Shoes Using Camera-Based Line-Laser Obstacle Detection System

    Directory of Open Access Journals (Sweden)

    Tzung-Han Lin

    2017-01-01

    Full Text Available Fall prevention is an important issue particularly for the elderly. This paper proposes a camera-based line-laser obstacle detection system to prevent falls in the indoor environment. When obstacles are detected, the system will emit alarm messages to catch the attention of the user. Because the elderly spend a lot of their time at home, the proposed line-laser obstacle detection system is designed mainly for indoor applications. Our obstacle detection system casts a laser line, which passes through a horizontal plane and has a specific height to the ground. A camera, whose optical axis has a specific inclined angle to the plane, will observe the laser pattern to obtain the potential obstacles. Based on this configuration, the distance between the obstacles and the system can be further determined by a perspective transformation called homography. After conducting the experiments, critical parameters of the algorithms can be determined, and the detected obstacles can be classified into different levels of danger, causing the system to send different alarm messages.

  3. Fall Prevention Shoes Using Camera-Based Line-Laser Obstacle Detection System.

    Science.gov (United States)

    Lin, Tzung-Han; Yang, Chi-Yun; Shih, Wen-Pin

    2017-01-01

    Fall prevention is an important issue particularly for the elderly. This paper proposes a camera-based line-laser obstacle detection system to prevent falls in the indoor environment. When obstacles are detected, the system will emit alarm messages to catch the attention of the user. Because the elderly spend a lot of their time at home, the proposed line-laser obstacle detection system is designed mainly for indoor applications. Our obstacle detection system casts a laser line, which passes through a horizontal plane and has a specific height to the ground. A camera, whose optical axis has a specific inclined angle to the plane, will observe the laser pattern to obtain the potential obstacles. Based on this configuration, the distance between the obstacles and the system can be further determined by a perspective transformation called homography. After conducting the experiments, critical parameters of the algorithms can be determined, and the detected obstacles can be classified into different levels of danger, causing the system to send different alarm messages.

  4. Argon and Nd:YAG lasers for caries prevention in enamel.

    Science.gov (United States)

    Tavares, Julieta Gomes; Eduardo, Carlos de Paula; Burnett, Luiz Henrique; Boff, Teonas Renato; de Freitas, Patrícia Moreira

    2012-08-01

    The aim of this study was to investigate the effect of Nd:YAG and argon laser irradiations on enamel demineralization after two different models to induce artificial caries. It is believed that the use of the high-intensity laser on the dental structure can lead to a more acid-resistant surface. Twenty-one extracted human third molars were sectioned into tooth quarters. The quarters were distributed in three groups: Group I (control), untreated; Group II, Nd:YAG laser (60 mJ, 15 pps, 47.77 J/cm(2), 30 sec); and Group III, argon laser (250 mW, 12 J/cm(2), 48 sec). Tooth quarters from each group were subjected to two different demineralization models: cycle 1, a 14 day demineralization (pH 4.5; 6 h) and remineralization (pH 7.0; 18 h) solutions, 37 °C and cycle 2, 48 h in demineralization solution (pH 4.5). Samples were prepared in slices (60-100 μm thick) to be evaluated under polarized light microscopy. Demineralization areas were measured (mm(2)) (n=11). Data were analyzed by ANOVA and Tukey's test (plaser was more effective for caries preventive treatment than Nd:YAG laser, showing a smaller demineralization area in enamel.

  5. Laser acupuncture and prevention of bone loss in tail-suspended rats.

    Science.gov (United States)

    Guo, Xia; Liu, Mu-Qing; Man, Hau-Cheung; Wang, Xiao-Yun; Mu, Jia-Ji; Li, Yong-Zhi; Feng, Jin-Sheng; Shi, San-Qiang; Zhang, Ming

    2010-10-01

    Skeletal unloading during spaceflight results in bone loss. This study investigated whether laser acupuncture could be an effective countermeasure to prevent unloading-induced bone loss in rats. There were 18 rats that were randomly assigned into three groups: a control group, a tail-suspended group (TS), and a tail-suspended with laser acupuncture treatment group (TSA). The rats in the TSA group were treated with laser acupuncture at the KI1 (Yong Quan) and ST36 (Zu San Li) acupoints of the left leg for 3 min per day. Bone mineral density (BMD), biomechanical properties, and histomorphometry of both tibiae were determined after the animals were euthanized at the end of week 4. Compared with the control group, BMD in the TS group significantly decreased by 12.3% in cortical bone and 15.1% in cancellous bone, whereas BMD in the TSA group decreased by only 3.1% in cortical bone and 9.0% in cancellous bone. The hardness of cortical bone dropped 44.1% in the TS group and 22.3% in the TSA group compared with the control group. The histomorphometry data were in accordance with BMD measurements. Although acupuncture treatment was applied only to the left side, we observed similar changes between the measurements of both the left and right tibiae. Laser acupuncture on KI1 and ST36 can inhibit bone loss in rats subjected to unloading. The fact that similar changes between the right and left sides when only the left limbs were treated suggests that the preventive effect of laser acupuncture occurs via a systemic regulation.

  6. [Ecotoxicology, human ecology, laser biotechnology in primary prevention of environmental health hazards].

    Science.gov (United States)

    Dobrowolski, J W

    2001-01-01

    Interdisciplinary studies in ecotoxicology (including the influence of complex physical, chemical and biological factors on ecosystems and human food chain), human ecology (related to estimation of individuals exposition to different pollutants both in the natural environment and in-door environment, as well as by food) and environmental biotechnology (based on application of high sensitive biological, especially embryological criteria in biotests for water quality, including image computisation and biosensors)--are scientific base for primary prevention of disturbances of the ecological balance as well as environmental risk factors for human health. Large scale applications of laser biostimulation in environmental engineering is a new chance for system approach in primary prevention by more efficient nutritional prevention, protection of proper water quality (including biotests) and protection of the human environment in working and living places.

  7. In vitro assessment of laser efficiency for caries prevention in pits and fissures.

    Science.gov (United States)

    Correa-Afonso, Alessandra M; Ciconne-Nogueira, Juliane C; Pécora, Jesus D; Palma-Dibb, Regina G

    2012-02-01

    This study aimed to assess the in vitro efficacy of the lasers Er:YAG, Nd:YAG, and CO(2) operating in the low energy mode for caries prevention in pits and fissures. Forty-five caries-free enamel occlusal sections were randomly divided into three groups: G1 - Er:YAG (80 mJ/2 Hz); G2 - Nd:YAG Laser (1 W and 10 Hz); and G3 - CO(2) Laser (0.4 W and 20 Hz). After surface treatment, the samples were submitted to challenge with acid consisting of a 10-day immersion in demineralizing (6 h) and remineralizing solution (18 h). Next, enamel demineralization was quantitatively evaluated by subsurface microhardness test and polarized-light microscopy (PLM, mm(2)) and qualitatively assessed by scanning electron microscopy. The Wilcoxon test was used for comparison of each group with its own control. ANOVA (α = 5%) was employed for comparison among groups, and Fisher's LSD multiple comparison test was applied, to check the difference in means. Concerning the microhardness analyses, statistical difference between control, and experimental areas was only detected for the CO(2) group. Experimental values were higher than the controls. As for PLM analyses, smaller demineralized areas were measured for G2 (Nd:YAG) and G3 (CO(2)) compared with the control areas. In conclusion, the present findings suggest that the CO(2) laser should be selected in order to increase the enamel resistance to acid in pits and fissures. Copyright © 2011 Wiley Periodicals, Inc.

  8. Efficacy of multiple exposure with low level He-Ne laser dose on acute wound healing: a pre-clinical study

    Science.gov (United States)

    Prabhu, Vijendra; Rao, Bola Sadashiva S.; Mahato, Krishna Kishore

    2014-02-01

    Investigations on the use of Low Level Laser Therapy (LLLT) for wound healing especially with the red laser light have demonstrated its pro-healing potential on a variety of pre-clinical and surgical wounds. However, until now, in LLLT the effect of multiple exposure of low dose laser irradiation on acute wound healing on well-designed pre-clinical model is not much explored. The present study aimed to investigate the effect of multiple exposure of low dose Helium Neon laser on healing progression of full thickness excision wounds in Swiss albino mice. Further, the efficacy of the multiple exposure of low dose laser irradiation was compared with the single exposure of optimum dose. Full thickness excision wounds (circular) of 15 mm diameter were created, and subsequently illuminated with the multiple exposures (1, 2, 3, 4 and 5 exposure/ week until healing) of He-Ne (632.8 nm, 4.02 mWcm-2) laser at 0.5 Jcm-2 along with single exposure of optimum laser dose (2 J/cm-2) and un-illuminated controls. Classical biophysical parameters such as contraction kinetics, area under the curve and the mean healing time were documented as the assessment parameters to examine the efficacy of multiple exposures with low level laser dose. Experimental findings substantiated that either single or multiple exposures of 0.5 J/cm2 failed to produce any detectable alterations on wound contraction, area under the curve and mean healing time compared to single exposure of optimum dose (2 Jcm-2) and un-illuminated controls. Single exposure of optimum, laser dose was found to be ideal for acute wound healing.

  9. Solar wind helium, neon and argon released by oxidation of metal grains from the Weston chondrite

    Science.gov (United States)

    Becker, R. H.; Rajan, R. S.; Rambaldi, E. R.

    1986-01-01

    A set of experiments were carried out to test the feasibility of determining unfractionated elemental and isotopic ratios for the noble gases in the presumably ancient solar wind present in the gas rich meteorites. The problems of diffusive loss was avoided by analyzing metal rather than the usual silicates. In order to avoid chemical, and even harsh physical, treatment of the sample, which might have affected the surfaces of metal grains, a means of analyzing the metal in the presence of residual silicate not removed by gentle crushing and magnetic separation was devised. Preliminary results given were obtained by taking advantage of the differing properties of metal and silicates with regard to diffusion. The results suggests that, with some modifications in the choice of pyrolysis and combustion temperatures and in the amount of O2 used, it should be possible, by oxidizing the surfaces of metal grains from gas rich meteorites, to obtain data on solar wind that has not been fractionated by diffusive loss.

  10. Topical hyperbaric oxygen and low energy laser therapy for chronic diabetic foot ulcers resistant to conventional treatment.

    Science.gov (United States)

    Landau, Z; Schattner, A

    2001-01-01

    Chronic foot ulcers are common in long-standing diabetes, may herald severe complications and are often resistant to therapy. To evaluate the effects of adjunctive topical hyperbaric oxygen treatment (THBO) and low energy laser (LEL) irradiation on ulcer healing, a 100 consecutive patients with chronic diabetic foot ulcers (DFU) refractory to 4.5 +/- 1.2 months of comprehensive treatment, were enrolled in a prospective open study. While conventional treatment was continued as necessary, THBO was administered by pumping 100 percent oxygen into a disposable sealed polythylene hyperbaric chamber (150 min x 2 to 3/wk at up to 1.04 atm). Helium-neon LEL irradiation was given concurrently using a Unilaser Scan Unit at 4 J/cm2 for 20 min. Some patients continued THBO at home or their treatment was confined to THBO at home. Patients were monitored every two weeks revealing 81 percent cure after 25 +/- 13 treatments over 3.2 +/- 1.7 months. On follow-up (median 18 months), only 3/81 (4 percent) had reulceration, which responded to THBO/LEL retreatment. Nonresponders had significantly lower ankle brachial indices (ABI) than patients whose ulcers were healed (0.55 vs. 0.78, p treatment program, constitutes an intriguing preliminary result. Thus, THBO/LEL therapy may be a safe, simple, and inexpensive early adjunctive treatment for patients with chronic diabetic foot ulcers. Our findings should prompt its evaluation by large randomized controlled trials.

  11. Apraclonidine versus brinzolamide-timolol combination to prevent intraocular pressure elevation after laser capsulotomy

    Directory of Open Access Journals (Sweden)

    Erkan Çelik

    2016-01-01

    Full Text Available AIM: To compare the efficacy of fixed combination of brinzolamide 1% and timolol 0.5%(FCBTwith apraclonidine 0.5%(APRAin preventing intraocular pressure(IOPelevations after neodymium: yttrium-aluminum-garnet(Nd:YAGlaser posterior capsulotomy.METHODS: This prospective randomized clinical study included 90 eyes of 90 consecutive patients who had Nd:YAG laser posterior capsulotomy for posterior capsule opacification(PCO. Patients were randomized to receive APRA(n=45or FCBT(n=45at 1h before laser surgery. A masked observer measured IOP by Goldmann applanation tonometry before the procedure and at 1, 2, 3, 24h and 7d after laser treatment. IOP outcome measures were grouped into the following categories: post laser IOP elevation of 5 to RESULTS:The mean IOP before surgery on the day of the procedure was 14.1±2.1 mm Hg in the APRA group and 13.2±2.1 mm Hg in the FCBT group. There was no statistically significant difference between the APRA and the FCBT groups of baseline IOPs measured(P=0.066. During the follow-up time, the mean IOP was lower in FCBT group, but this was not statistically significant. Six patients(13.3%in APRA group and 4(8.9%in FCBT group had IOP elevations of 5 to P=0.243. IOP elevations of 10 mm Hg or more occurred in 3 eyes(6.7%in the APRA group and 1 eyes(2.2%in the FCBT group; this was not statistically significant(P=0.542. CONCLUSION:Both of APRA and FCBT are effective for prevention and APRA is enough for most of routine cases. FCBT may be an option for the eyes those need more IOP reduction such as pre-existing glaucoma patients who are at higher risk for postoperative IOP elevations.

  12. Prevention of intraocular pressure elevation after argon laser trabeculoplasty in primary open angle glaucoma

    Directory of Open Access Journals (Sweden)

    Božić Marija

    2011-01-01

    Full Text Available Introduction. Argon laser trabeculoplasty (ALT is an intraocular pressure lowering method that is overall safe and powerful, but often complicated by transient postoperative intraocular pressure rises. In prevention of this complication, we frequently use two potent alpha-adrenergic agonists - brimonidine and apraclonidine. Objective. The aim of this study was to compare brimonidine 0.2% and apraclonidine 0.5% efficacy and safety in prevention of intraocular pressure elevation after ALT. Methods. This was a prospective, randomized, double-masked and comparative study. This study included 27 POAG patients, 15 received 0.2% brimonidine, and 12 received 0.5% apraclonidine before laser surgery (22 eyes in both groups. Intraocular pressure readings were taken 1, 2, 3, 24 hours and 7 days after ALT. Student’s t-test was used to analyze data between two groups, and χ2 test to compare data within groups. Value p less than 0.05 was considered statistically significant. Results. We found statistically significantly lower IOP in eyes that received 0.2% brimonidine at readings taken 1 hour after ALT (p=0.001. There were no statistically significant differences in other IOP readings between two groups. Conclusion. A single preoperative drop of brimonidine 0.2% had similar efficacy and safety as apraclonidine 0.5% in preventing transient IOP elevations after ALT.

  13. Induction of complete wound healing in recalcitrant ulcers by low-intensity laser irradiation depends on ulcer cause and size.

    Science.gov (United States)

    Schindl, M; Kerschan, K; Schindl, A; Schön, H; Heinzl, H; Schindl, L

    1999-02-01

    Chronic skin ulcers still represent a therapeutic challenge in dermatology. Among the various non-invasive treatment modalities used for the improvement of impaired wound healing, low-intensity laser irradiations are gaining an increasing body of interest. We used low-intensity laser irradiations delivered by a 30 mW helium-neon laser at an energy density of 30 J/cm2 three times weekly for the induction of wound healing in ulcers of diverse causes. Twenty patients with the same number of ulcers, which had previously been treated by conventional wound care for a median period of 34 weeks (range: 3-120 weeks) without any significant evidence of healing, were included in the study. Concerning the underlying disorders, patients were divided into four groups: diabetes, arterial insufficiency, radio damage and autoimmune vasculitis. In all ulcers, complete epithelization could be induced by laser therapy. No amputation or any other surgical intervention was necessary and no adverse effects of any kind were noted during low-intensity laser treatment. Regarding the different diagnoses, a statistically significant difference was noted (P = 0.008): ulcers due to radio damage healed significantly faster than those caused by diabetes (6 weeks [range: 3-10 weeks] vs. 16 weeks [range: 9-45 weeks], P = 0.005). Wound healing in autoimmune vasculitis (24 weeks [range: 20-35 weeks]) required longer than in radiodermitis, although the difference was not significant. In addition to the diagnosis, wound size was found to be an important factor influencing the duration of wound closure (P = 0.028), whereas duration of previous conventional treatment (P = 0.24) and depth (P = 0.14) showed no effect. Our results indicate that low-intensity laser irradiation could be a valuable non-invasive tool for the induction of wound healing in recalcitrant ulcers, and that healing time is correlated with the ulcer cause and size.

  14. Use of 660-nm diode laser in the prevention and treatment of human oral mucositis induced by radiotherapy and chemotherapy.

    Science.gov (United States)

    Zanin, Taís; Zanin, Fatima; Carvalhosa, Artur Aburad; Castro, Paulo Henrique de Souza; Pacheco, Marcos Tadeu; Zanin, Iriana Carla Junqueira; Brugnera, Aldo

    2010-04-01

    The aim of this multidisciplinary study was to evaluate quantitatively and qualitatively the effect of a 660-nm diode laser in the prevention and treatment of human oral mucositis (OM) in patients suffering from head and neck cancer who had undergone radiotherapy and chemotherapy. OM is a severe oral lesion resulting from the toxic effects of treatment for cancer in the head and neck region. Low-level laser therapy is indicated to prevent and treat this oral complication and may be used alone or in association with conventional drug treatment, producing pain relief and wound repair. This study included 72 patients with head and neck cancer treated at the Cancer Hospital of Mato-Grosso, Brazil, and divided into a control group (C; n = 36) and a laser group (L; n = 36). Laser therapy was performed in combination with radiotherapy and chemotherapy twice a week using a diode laser (lambda = 660 nm, power = 30 mW, spot size = 2 mm, energy = 2 J per point). Statistically significant differences were observed between the two groups. Patients in group L usually did not present with OM or pain, but all patients in group C presented with OM ranging from Level I to III associated with pain. This difference was significant from week 1 on, increased until week 4 and remained stable up to week 7. Laser therapy was effective in preventing and treating oral effects induced by radiotherapy and chemotherapy, thus improving the patient's quality of life.

  15. Low-level laser in prevention and treatment of oral mucositis in pediatric patients with acute lymphoblastic leukemia.

    Science.gov (United States)

    de Castro, Jurema Freire Lisboa; Abreu, Elizabeth Galamba Fernandes; Correia, Andreza Veruska Lira; da Mota Vasconcelos Brasil, Catarina; da Cruz Perez, Danyel Elias; de Paula Ramos Pedrosa, Francisco

    2013-12-01

    The aim of this study was to evaluate the influence of low-level laser therapy (LLLT) on the prevention and treatment of oral mucositis (OM) in pediatric cancer patients taking methotrexate. OM is a very common, potentially severe side effect, caused by treatment with radiotherapy and chemotherapy for cancer. Forty patients with acute lymphoblastic leukemia, who received high doses of methotrexate, were distributed into two groups. Group A (Preventive Group) was composed of patients who received preventive laser (red-subgroup A1 or infrared-subgroup A2) for 5 days, beginning on the 1st day of infusion. Group B (Treatment Group) was composed of patients who received laser treatment only if they developed post-chemotherapy mucositis (red-subgroup B1 or infrared-subgroup B2). Laser was used at wavelengths of 660 or 830 nm with output 100 mW, power density 3.57 W/cm(2), spot size 0.028 cm(2), energy of 1 J, resulting in an energy density of 35 J/cm(2) for 10 sec in the prophylactic group, and energy of 2 J, resulting in energy density of 70 J/cm(2) for 20 sec in the therapeutic group. The percentage of patients who did not develop OM was higher in Group A (60% vs. 25%). In Group B, 3/20 patients developed grade IV OM (15%), and a significant difference was found between the two subgroups at the end of treatment (p=0.019). Prophylactic laser produced a better outcome than when patients did not receive any preventive intervention, and red laser (660 nm) was better than infrared (830 nm) in the prevention and treatment of OM.

  16. B-Cure Laser Dental Pro technology for prevention and treatment of peri-implant mucositis

    Science.gov (United States)

    Gileva, O. S.; Libik, T. V.; Chuprakov, M. A.; Yakov, A. Y.; Mirsaeva, F. Z.

    2017-09-01

    Oral mucositis (OM) is the severe inflammation, lesioning and ulceration of the epithelia, accompanied by bleeding and intensive pain. OM is a common complication of dental implantation. Low-level laser therapy (LLLT) has been found to enhance the repair and healing of epithelia. The aim of this study was to evaluate the effectiveness of preventive and treatment use of LLLT (B-Cure Laser Dental Pro technology in original author's techniques) in the patients who have undergone dental implantation. Simple blind randomized prospective one-center comparative placebo-controlled clinical trial is carried out on the group of 30 partially edentulous patients. It is proved that the use of LLLT before and after installation of dental implants provides: 1) reliable reduction (by 3.5 times) of the frequency of implication and intensity of pain in the first days after operation; 2) reduction (by 3.3-3.7 times) of frequency, duration and intensity of local edematous and inflammatory processes in peri-implant zone and facial soft tissue edema; 3) effective prophylaxis of postoperative sensory, paresthesia and neurologic disturbances in maxillofacial area.

  17. Pre-operative therapeutic eyelid hygiene in the prevention of complications following excimer laser vision correction

    Directory of Open Access Journals (Sweden)

    V. V. Kurenkov

    2012-01-01

    Full Text Available Purpose: to assess the effectiveness of pre-operative therapeutic eyelid hygiene in the prevention and treatment of dry eye and meibomian glands dysfunction following excimer laser vision surgery.Methods: In enrolled 144 patients (288 eyes, ocular surface and meibomian glands functions were evaluated before and following refractive surgery (LASIK and REIK. In pre- and post-operative period, standard ophthalmological studies were performed, including best-corrected visual acuity determination, biomicroscopy, Schirmer’s test and Norn’s test (tear break-up time. In pre-operative pe- riod, ocular surface microbial profile was assessed. Subjective symptoms of impaired tear production were revealed via questioning. In study group (70 patients, 140 eyes, therapeutic eyelid hygiene using Blefarogel 1 or Blefarogel 2 (Ltd. Heltec-Medica, Moscow, Russia was prescribed one week before surgery. In control group, no therapeutic eyelid hygiene was prescribed. All patients were received antibacterial treatment including Vigamox (Alcon, Fort Worth, tX. In both groups, Natural tears and Systane Ultra (Alcon were used as tear replacement therapy.Results: Complex treatment, including therapeutic eyelid hygiene in study group, significantly improved tear film and ocular sur- face health as well as meibomian glands functions. Inflammatory complications rate was estimated as 5.7% in study group and 10.6% in control group.Conclusion: therapeutic eyelid hygiene is highly effective in the prophylaxis and treatment of post-operative complications duу to ocular surface pathology and meibomian glands dysfunction. the procedure is safe and can be recommended as a part of complex preventive treatment before excimer laser vision correction.

  18. Pre-operative therapeutic eyelid hygiene in the prevention of complications following excimer laser vision correction

    Directory of Open Access Journals (Sweden)

    V. V. Kurenkov

    2014-07-01

    Full Text Available Purpose: to assess the effectiveness of pre-operative therapeutic eyelid hygiene in the prevention and treatment of dry eye and meibomian glands dysfunction following excimer laser vision surgery.Methods: In enrolled 144 patients (288 eyes, ocular surface and meibomian glands functions were evaluated before and following refractive surgery (LASIK and REIK. In pre- and post-operative period, standard ophthalmological studies were performed, including best-corrected visual acuity determination, biomicroscopy, Schirmer’s test and Norn’s test (tear break-up time. In pre-operative pe- riod, ocular surface microbial profile was assessed. Subjective symptoms of impaired tear production were revealed via questioning. In study group (70 patients, 140 eyes, therapeutic eyelid hygiene using Blefarogel 1 or Blefarogel 2 (Ltd. Heltec-Medica, Moscow, Russia was prescribed one week before surgery. In control group, no therapeutic eyelid hygiene was prescribed. All patients were received antibacterial treatment including Vigamox (Alcon, Fort Worth, tX. In both groups, Natural tears and Systane Ultra (Alcon were used as tear replacement therapy.Results: Complex treatment, including therapeutic eyelid hygiene in study group, significantly improved tear film and ocular sur- face health as well as meibomian glands functions. Inflammatory complications rate was estimated as 5.7% in study group and 10.6% in control group.Conclusion: therapeutic eyelid hygiene is highly effective in the prophylaxis and treatment of post-operative complications duу to ocular surface pathology and meibomian glands dysfunction. the procedure is safe and can be recommended as a part of complex preventive treatment before excimer laser vision correction.

  19. Low level laser therapy against radiation induced oral mucositis in elderly head and neck cancer patients-a randomized placebo controlled trial.

    Science.gov (United States)

    Gautam, Ajay Prashad; Fernandes, Donald J; Vidyasagar, Mamidipudi S; Maiya, Arun G; Guddattu, Vausudev

    2015-03-01

    Radiotherapy (RT) is treatment of choice for Elderly Head and Neck Cancer (HNC) patients. Oral mucositis (OM) during RT affects patient's routine oral activities and overall health. Low Level Laser Therapy (LLLT) provided some promising results against cancer therapy induced OM in children and adults. No study specifically evaluated effects of LLLT against RT induced OM in elderly HNC patients until date, hence we did this study. This double blinded study randomized 46 elderly HNC patients scheduled for RT [Dosage=66 Gray (2 Gy/fraction), 5 fractions/week, total 33 fractions for 6.5 weeks], into laser (22) and placebo (24) groups. Laser group patients received LLLT [Helium-Neon, λ=632.8 nm, power density=0.024 W/cm(2), dosage=3.0 J/point at six anatomical sites bilaterally i.e. 12 locations, total dose/session=36 J, beam aperture diameter=0.6 mm, beam spot size=1 cm(2), irradiated area diameter=1 cm(2), irradiation time/point=125 s, 5 sessions/week, non-contact method-distance between probe and irradiated tissues laser. OM grades (RTOG/EORTC Scale), oral pain, weight loss, need for morphine analgesics and tube feeding, and RT break were recorded by a blinded assessor. Descriptive statistics and repeated measures ANOVA were used for analysis keeping plaser than placebo group. No difference was found for enteral feeding use (p=0.667) between two groups. LLLT decreased the severity of OM and oral pain in elderly HNC patients. Also, lesser weight loss, morphine analgesic use and radiation break happened in laser group. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Topical hyperbaric oxygen and low-energy laser for the treatment of chronic ulcers.

    Science.gov (United States)

    Landau, Zvi; Sommer, Ahuva; Miller, Edward B

    2006-07-01

    Diabetic foot ulcers (DFU) and chronic venous ulcers (CVU) are persistent cutaneous lesions that are difficult to treat and heal. Topical hyperbaric oxygen (THO) and low-energy laser (LEL) are therapies that have been employed separately for ulcer treatment, but their concomitant use has not been investigated. In this unblinded, open-label non-randomized trial, we treated 374 consecutive patients with treatment-refractory chronic ulcers (218 patients with DFU and 156 individuals with CVU) with a combination of THO and LEL. THO was administered by pumping 100% oxygen into a disposable, sealed polyethylene chamber for 2 h, two to three times weekly. LEL was administered concurrently using a helium-neon laser at 4 J/cm(2) for 20 min. Complete ulcer closure was obtained in 78% of patients in each group (170 patients with DFU and 127 patients with CVU). Treatment failure resulting in amputation in DFU was seen in 48 patients (22%); non-closure of ulcers within 18 months in individuals with CVU was seen in 29 (22%). The length of therapy was also similar in the two groups (3.7+/-3 versus 4.1+/-3 months in DFU and CVU cohorts, respectively). However, the number of treatments required to affect healing was greater in the CVU group than among the DFU patients (40+/-25 versus 31.4+/-20 treatments). THO and LEL therapies are safe, effective, simple and inexpensive therapies for DFU and CVU. Confirmation must await the performance of double-blind, randomized, controlled trials currently under way.

  1. Endodontic applications of a short pulsed FR Nd:YAG dental laser: photovaporization of extruded pulpal tissue following traumatic fractures of two maxillary central incisors--a clinical trial repor

    Science.gov (United States)

    Gregg, Robert H., II

    1992-06-01

    Historically, many techniques have been attempted in the search for a satisfactory and consistent treatment of inflamed, painful, hyperemic pulpal tissue. Present techniques attempting to achieve profound local anesthesia in such tissue, have not been satisfactory. Local anesthesia techniques acceptable to the patient with painful hyperemic pulpal tissue, has eluded previous technology. The subsequent treatment of hyperemic tissue without sufficient anesthesia primarily involves undesirable invasive mechanical/surgical procedures. Described in this clinical trial is a technique using free running (FR) pulsed, Nd:YAG laser energy to ablate soft tooth pulpal tissue--a technique employed after conventional endodontic methods failed. A free running pulsed, FR Nd:YAG dental laser was successfully used at 20 pulses per second and 1.25 watts to photovaporize endodontic pulpal tissue (pulpectomy) to allow a conventional endodontic file to extirpate the remaining soft tissue remnants and access the root apex. Also described in this paper is the 'hot-tip' effect of contact fiber laser surgery. This clinical trial achieved the immediate, short term objective of endodontic soft tissue removal via photovaporization, without pain reported by the patient. The pulsed FR Nd:YAG dental laser used as described in this clinical report appears to be a very safe and very effective technique; offers a treatment alternative to traditional therapy that suggests high patient acceptance; and is significantly less stressful for the doctor and staff than traditional treatment options. Long-term, controlled scientific and clinical studies are necessary to establish the safety and efficacy of both the helium-neon energy for visualization and the low-watt pulsed FR Nd:YAG energy for photovaporization of soft endodontic pulpal tissue within the root canal. Research is especially needed to understand the effects of a low-watt, pulsed FR, Nd:YAG laser on the activity of osteoclasts and odontoclasts

  2. Transmyocardial laser revascularization fails to prevent left ventricular functional deterioration and aneurysm formation after acute myocardial infarction in sheep.

    Science.gov (United States)

    Malekan, R; Kelley, S T; Suzuki, Y; Reynolds, C; Plappert, T; Sutton, M S; Edmunds, L H; Bridges, C R

    1998-11-01

    Transmyocardial laser revascularization is an investigational technique for revascularizing ischemic myocardium in patients with inoperable coronary arterial disease. This study tests the hypothesis that laser revascularization prevents left ventricular functional deterioration and aneurysm formation after acute anteroapical myocardial infarction. An ultrasonic ascending aortic flow probe and snares around the distal left anterior descending and second diagonal coronary arteries were placed in 26 Dorsett hybrid sheep. Ten to 14 days later, snared arteries were occluded to produce an anteroapical infarction of 23% of left ventricular mass. Before infarction 14 animals had 34 +/- 4 transmyocardial perforations in the area of the anticipated infarction made with a carbon dioxide laser. Twelve animals served as controls. Hemodynamic measurements and transdiaphragmatic quantitative echocardiograms were obtained before, immediately after, and 2, 5, and 8 weeks after infarction. Eighteen sheep completed the protocol. All animals had large anteroapical left ventricular aneurysms with massive ventricular enlargement. Immediately after infarction the anterior wall became thinner and dyskinetic in all sheep. At 8 weeks aneurysmal size and shape were indistinguishable between groups. Two days after infarction, laser holes were filled with fibrin. At 5 and 8 weeks the infarct consisted of dense collagen, fibroblasts, scattered calcifications, myocyte fragments, neutrophils, macrophages, and no laser holes. There were no significant differences at any time between groups for cardiac pressures or output, ventricular volumes, ejection fraction, stroke work, and the stroke work-left ventricular end-diastolic pressure index. Transmyocardial laser perforations do not revascularize acute myocardial infarction in sheep.

  3. Laser process and corresponding structures for fabrication of solar cells with shunt prevention dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Harley, Gabriel; Smith, David D.; Dennis, Tim; Waldhauer, Ann; Kim, Taeseok; Cousins, Peter John

    2017-11-28

    Contact holes of solar cells are formed by laser ablation to accommodate various solar cell designs. Use of a laser to form the contact holes is facilitated by replacing films formed on the diffusion regions with a film that has substantially uniform thickness. Contact holes may be formed to deep diffusion regions to increase the laser ablation process margins. The laser configuration may be tailored to form contact holes through dielectric films of varying thicknesses.

  4. The use of sub-ablative Er:YAG laser irradiation in prevention of dental caries during orthodontic treatment.

    Science.gov (United States)

    Fornaini, Carlo; Brulat, Nathalie; Milia, Giulia; Rockl, Andrea; Rocca, Jean-Paul

    2014-09-30

    This « in-vitro » study had two specific aims: the first, to test using a universal testing machine whether sub-ablative Er:YAG laser irradiation prior to acid etching is effective in orthodontic bracket bonding and secondly using micro-hardness measurements and Scanning Electron Microscopy (SEM) observations to investigate the effectiveness of de-mineralization reduction in enamel treated with sub-ablative Er:YAG laser irradiation followed by fluoride varnish application. One hundred and eighty bovine permanent maxillary incisors were selected for shear bond strength testing and microhardness measurements. Sub-ablative Er:YAG laser irradiation was set at a power density of 2.5 J/cm(2), a frequency of 7 Hz and air/water spray. Brackets were bonded with an auto-curing resin paste. The shear bond strength was measured comparing laser irradiated and non-irradiated enamel surface, followed by SEM observation of the bracket-resin-enamel interface. Microhardness measurements were made on enamel samples before treatment, after samples preparation, and after demineralization. While the adhesion of orthodontic brackets to bovine enamel after sub-ablative Er:YAG laser irradiation and acid etching is comparable to that obtained after conventional acid etching, the effect of laser irradiation associated with topical application of fluoride varnish increases the microhardness of enamel. Sub-ablative Er:YAG laser irradiation before the acid etching doesn't reduce the shear bond whereas when associated with fluoride application it may play a role in caries prevention. Further studies will be necessary to establish the mechanism by which the protective laser activated fluoride effect is achieved.

  5. Absorption and thermal study of dental enamel when irradiated with Nd:YAG laser with the aim of caries prevention

    Science.gov (United States)

    Boari, H. G. D.; Ana, P. A.; Eduardo, C. P.; Powell, G. L.; Zezell, D. M.

    2009-07-01

    It is widely recognized that Nd:YAG can increase enamel resistance to demineralization; however, the safe parameters and conditions that enable the application of Nd:YAG laser irradiation in vivo are still unknown. The aim of this study was to determine a dye as a photoabsorber for Nd:YAG laser and to verify in vitro a safe condition of Nd:YAG irradiation for caries prevention. Fifty-eight human teeth were selected. In a first morphological study, four dyes (waterproof India ink., iron oxide, caries indicator and coal paste) were tested before Nd:YAG laser irradiation, under two different irradiation conditions: 60 mJ/pulse and 10 Hz (84.9 J/cm2); 80 mJ/pulse and 10 Hz (113.1 J/cm2). In a second study, the enamel surface and pulp chamber temperatures were evaluated during laser irradiations. All dyes produced enamel surface melting, with the exception of the caries indicator, and coal paste was the only dye that could be completely removed. All irradiation conditions produced temperature increases of up to 615.08°C on the enamel surface. Nd:YAG laser irradiation at 60 mJ/pulse, 10 Hz and 84.9 J/cm2 promoted no harmful temperature increase in the pulp chamber (ANOVA, p < 0.05). Among all dyes tested, the coal paste was an efficient photoabsorber for Nd:YAG irradiation, considered feasible for clinical practice. Nd:YAG laser at 84.9 J/cm2 can be indicated as a safe parameter for use in caries prevention.

  6. Effect of Nd:YAG laser combined with fluoride on the prevention of primary tooth enamel demineralization.

    Science.gov (United States)

    Azevedo, Danielle Torres; Faraoni-Romano, Juliana Jendiroba; Derceli, Juliana Dos Reis; Palma-Dibb, Regina Guenka

    2012-01-01

    Most studies dealing with the caries preventive action of Nd:YAG laser have been done in permanent teeth and studies on primary teeth are still lacking. The aim of this study was to evaluate in vitro the effect of Nd:YAG laser combined or not with fluoride sources on the acid resistance of primary tooth enamel after artificial caries induction by assessing longitudinal microhardness and demineralization depth. Sixty enamel blocks obtained from the buccal/lingual surface of exfoliated human primary molars were coated with nail polish/wax, leaving only a 9 mm² area exposed on the outer enamel surface, and randomly assigned to 6 groups (n=10) according to the type of treatment: C-control (no treatment); APF: 1.23% acidulated phosphate fluoride gel; FV: 5% fluoride varnish; L: Nd:YAG laser 0.5 W/10 Hz in contact mode; APFL: fluoride gel + laser; FVL: fluoride varnish + laser. After treatment, the specimens were subjected to a des-remineralization cycle for induction of artificial caries lesions. Longitudinal microhardness data (%LMC) were analyzed by the Kruskal-Wallis test and demineralization depth data were analyzed by oneway ANOVA and Fisher's LSD test (á=0.05). APFL and APF groups presented the lowest percentage of microhardness change (p<0.05). Demineralization depth was smaller in all treated groups compared with the untreated control. In conclusion, Nd:YAG laser combined or not with fluoride gel/varnish was not more effective than fluoride alone to prevent enamel demineralization within the experimental period.

  7. Nanocomposited coatings produced by laser-assisted process to prevent silicone hydogels from protein fouling and bacterial contamination

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Guobang; Chen, Yi; Zhang, Jin, E-mail: jzhang@eng.uwo.ca

    2016-01-01

    Graphical abstract: Nanocomposited-coating was deposited on silicone hydrogel by using the matrix-assisted pulsed laser evaporation (MAPLE) process. The ZnO–PEG nanocomposited coating reduces over 50% protein absorption on silicone hydrogel, and can inhibit the bacterial growth efficiently. - Highlights: • We developed a nanocomposited coating to prevent silicone hydrogel from biofouling. • Matrix-assisted pulsed laser evaporation can deposit inorganic–organic nanomaterials. • The designed nanocomposited coating reduces protein absorption by over 50%. • The designed nanocomposited coating shows significant antimicrobial efficiency. - Abstract: Zinc oxide (ZnO) nanoparticles incorporating with polyethylene glycol (PEG) were deposited together on the surface of silicone hydrogel through matrix-assisted pulsed laser evaporation (MAPLE). In this process, frozen nanocomposites (ZnO–PEG) in isopropanol were irradiated under a pulsed Nd:YAG laser at 532 nm for 1 h. Our results indicate that the MAPLE process is able to maintain the chemical backbone of polymer and prevent the nanocomposite coating from contamination. The ZnO–PEG nanocomposited coating reduces over 50% protein absorption on silicone hydrogel. The cytotoxicity study shows that the ZnO–PEG nanocomposites deposited on silicone hydrogels do not impose the toxic effect on mouse NIH/3T3 cells. In addition, MAPLE-deposited ZnO–PEG nanocomposites can inhibit the bacterial growth significantly.

  8. Low-level laser therapy for wound healing: mechanism and efficacy.

    Science.gov (United States)

    Posten, William; Wrone, David A; Dover, Jeffrey S; Arndt, Kenneth A; Silapunt, Sirunya; Alam, Murad

    2005-03-01

    Given the recent interest in light-emitting diode (LED) photomodulation and minimally invasive nonablative laser therapies, it is timely to investigate reports that low-level laser therapy (LLLT) may have utility in wound healing. To critically evaluate reported in vitro models and in vivo animal and human studies and to assess the qualitative and quantitative sufficiency of evidence for the efficacy of LLLT in promoting wound healing. Literature review, 1965 to 2003. In examining the effects of LLLT on cell cultures in vitro, some articles report an increase in cell proliferation and collagen production using specific and somewhat arbitrary laser settings with the helium neon (HeNe) and gallium arsenide lasers, but none of the available studies address the mechanism, whether photothermal, photochemical, or photomechanical, whereby LLLT may be exerting its effect. Some studies, especially those using HeNe lasers, report improvements in surgical wound healing in a rodent model; however, these results have not been duplicated in animals such as pigs, which have skin that more closely resembles that of humans. In humans, beneficial effects on superficial wound healing found in small case series have not been replicated in larger studies. To better understand the utility of LLLT in cutaneous wound healing, good clinical studies that correlate cellular effects and biologic processes are needed. Future studies should be well-controlled investigations with rational selection of lasers and treatment parameters. In the absence of such studies, the literature does not appear to support widespread use of LLLT in wound healing at this time. Although applications of high-energy (10-100 W) lasers are well established with significant supportive literature and widespread use, conflicting studies in the literature have limited low-level laser therapy (LLLT) use in the United States to investigational use only. Yet LLLT is used clinically in many other areas, including Canada

  9. Preparation Femtosecond Laser Prevention for the Cold-Worked Stress Corrosion Crackings on Reactor Grade Low Carbon Stainless Steel

    CERN Document Server

    John Minehara, Eisuke

    2004-01-01

    We report here that the femtosecond lasers like low average power Ti:Sapphire lasers, the JAERI high average power free-electron laser and others could peel off and remove two stress corrosion cracking (SCC) origins of the cold-worked and the cracking susceptible material, and residual tensile stress in hardened and stretched surface of low-carbon stainless steel cubic samples for nuclear reactor internals as a proof of principle experiment except for the third origin of corrosive environment. Because a 143 °C and 43% MgCl2 hot solution SCC test was performed for the samples to simulate the cold-worked SCC phenomena of the internals to show no crack at the laser-peered off strip on the cold-worked side and ten-thousands of cracks at the non-peeled off on the same side, it has been successfully demonstrated that the femtosecond lasers could clearly remove the two SCC origins and could resultantly prevent the cold-worked SCC.

  10. Lasers.

    Science.gov (United States)

    Passeron, T

    2012-12-01

    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be successfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-au-lait macules should not be treated as the relapses are nearly constant. Due to its complex pathophysiology, melasma has a special place in hyperpigmented dermatoses. Q-switched lasers (using standard parameters or low fluency) should not be used because of consistent relapses and the high risk of post-inflammatory hyperpigmentation. Paradoxically, targeting the vascular component of the melasma lesion with lasers could have a beneficial effect. However, these results have yet to be confirmed. In all cases, a precise diagnosis of the type of hyperpigmentation is mandatory before any laser treatment, and the limits and the potential side effects of the treatment must be clearly explained to patients. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  11. [Lasers].

    Science.gov (United States)

    Passeron, T

    2012-11-01

    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be successfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-au-lait macules should not be treated as the relapses are nearly constant. Due to its complex pathophysiology, melasma has a special place in hyperpigmented dermatoses. Q-switched lasers (using standard parameters or low fluency) should not be used because of consistent relapses and the high risk of post-inflammatory hyperpigmentation. Paradoxically, targeting the vascular component of the melasma lesion with lasers could have a beneficial effect. However, these results have yet to be confirmed. In all cases, a precise diagnosis of the type of hyperpigmentation is mandatory before any laser treatment, and the limits and the potential side effects of the treatment must be clearly explained to patients. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  12. In-vivo occlusal caries prevention by pulsed CO2 -laser and fluoride varnish treatment--a clinical pilot study.

    Science.gov (United States)

    Rechmann, Peter; Charland, Daniel A; Rechmann, Beate M T; Le, Charles Q; Featherstone, John D B

    2013-07-01

    High caries prevalence in occlusal pits and fissures warrants novel prevention methods. An 86% reduction in dental enamel smooth surface demineralization in-vivo following short-pulsed 9.6 µm-CO(2) -laser irradiation was recently reported. The objective of this study was to conduct a blinded 12-month-pilot clinical trial of occlusal pit and fissure caries inhibition using the same CO(2) -laser irradiation conditions. Twenty subjects, average age 14 years, were recruited. At baseline, second molars were randomized into test and control groups, assessed by International Caries Detection & Assessment System (ICDAS-II), SOPROLIFE light-induced fluorescence evaluator in daylight and blue-fluorescence mode and DIAGNOdent. An independent investigator irradiated test molars with a CO(2) -laser, wavelength 9.6 µm, pulse-duration 20 µs, pulse-repetition-rate 20 Hz, beam diameter 800 µm, average fluence 4.5 ± 0.5 J/cm(2), 20 laser pulses per spot. At 3-, 6- and 12-month recall teeth were assessed by ICDAS, SOPROLIFE and DIAGNOdent. All subjects received fluoride varnish applications at baseline and 6-month recall. All subjects completed the 3-month, 19 the 6-month and 16 the 12-month recall. At all recalls average ICDAS scores had decreased for the test and increased for the control fissures (laser vs. control, 3-month: -0.10 ± 0.14, 0.30 ± 0.18, P > 0.05; 6-month: -0.26 ± 0.13, 0.47 ± 0.16, P = 0.001; 12-month: -0.31 ± 0.15, 0.75 ± 0.17, P laser vs. control, 6-month: 0.22 ± 0.13, 0.17 ± 0.09, P = 0.02; 12-month: 0.28 ± 0.19, 0.25 ± 0.17, P = 0.03). For SOPROLIFE blue-fluorescence evaluation mean changes in comparison to baseline for the control and the laser treated teeth were also statistically significant for the 6- and 12-month recall. Specific microsecond short-pulsed 9.6 µm CO(2) -laser irradiation markedly inhibits caries progression in pits and fissures in comparison to

  13. Low energy laser in prevention of oral mucositis in patients receiving radiotherapy and/or chemotherapy in Pernambuco Cancer Hospital

    Energy Technology Data Exchange (ETDEWEB)

    Kelner, Natalie; Castro, Jurema Freire Lisboa de [Federal University of Pernambuco, Recife (Brazil). Dept. of Clinics and Preventive Dentistry. Discipline of Oral Pathology]. E-mail: jlisboa72@hotmail.com

    2007-07-01

    Oral mucositis induced by antineoplastic therapy causes wide-range pain and discomfort resulting in decreased quality of life. The present study evaluated the benefits of low intensity laser and 0.12% chlorhexidine gluconate in the prevention of oral mucositis induced by radiation, associated or not with chemotherapy, and considered degrees/severity, time of appearance of the lesions and functional loss. Eighty-four outpatients were considered and 49 were included in this study and divided into two groups: Group 1 received laser treatments in three stages, starting three days before treatment until the end of therapy. Group 2 was instructed to do daily mouth rinses with chlorhexidine gluconate. The prevalence of clinical mucositis was 49%, and of functional mucositis, 28.6%, when the two groups were considered together. This percentage was smaller in the laser group, 44% for the clinical mucositis group and 24% for the functional. The two protocols were well tolerated and showed benefits, mainly from the point of view of functionality, and delayed the onset and development of mucositis. (author)

  14. Pulpal safety of a 9.6-μm TEA CO2 laser used for caries prevention

    Science.gov (United States)

    Goodis, Harold E.; Fried, Daniel; Featherstone, John D. B.

    2002-06-01

    Lasers are used for several procedures involving hard and soft tissues of the oral cavity. Included in those procedures is the use of the CO2 laser to alter the surface structure of tooth enamel to render it more resistant to caries. A new 9.6micrometers wavelength TEA CO2 laser (Argu Photonics, Jpiter, FL) has been investigated as a device that can be used for this procedure without harming the dental pulp. Erupted, caries and restoration free third molars (n=24) were used in the experiment. Teeth were irradiated at an incident fluence of 1.5J/cm2 and a repetition rate of 10Hz and a spot size 1mm in diameter. At the low and high settings, 200 to 400 pulses were delivered at 12mJ per pulse for a total energy of 2.4 or 4.8J delivered for 20 or 40 seconds respectively. Other teeth were subjected to a sham dental procedure (positive control) or no procedure (negative control). Prior to testing, radiographs were taken of all teeth, and they were tested pulpally using heat, cold and electricity to determine vitality. The teeth were removed either immediately or at one week or one month after testing. They were bioprepared and examined histologically for signs of inflammation. Only one tooth developed symptoms of sensitivity to cold for 10 days following exposure to the high power level. The sensitivity was of fleeting duration and was judged to be reversible pulpitis. All teeth tested responded normally at pretesting and pre-extraction time periods. Histological examination disclosed no indication of an inflammatory response in the pulp tissue. All sections appeared normal with no changes seen in the normal pulpal morphology. We conclude that the 9.6 micrometers wavelength laser causes no pulpal damage at the energy levels used and can be used safely for caries prevention treatments.

  15. Variability of helium, neon, and argon in the lunar exosphere as observed by the LADEE NMS instrument

    National Research Council Canada - National Science Library

    Benna, M; Mahaffy, P. R; Halekas, J. S; Elphic, R. C; Delory, G. T

    2015-01-01

    .... Helium was found to be controlled by the supply of solar wind alpha particles and by the presence of an endogenous source that supplies the exosphere at a rate of 1.9 × 10 23  atoms s −1...

  16. Prevention

    Science.gov (United States)

    Kerry Britton; Barbara Illman; Gary Man

    2010-01-01

    Prevention is considered the most cost-effective element of the Forest Service Invasive Species Strategy (USDA Forest Service 2004). What makes prevention difficult is the desire to maximize free trade and the resulting benefits to society while, at the same time, protecting natural resources. The role of science is to first identify which commodities pose an...

  17. Prevention

    DEFF Research Database (Denmark)

    Halken, S; Høst, A

    2001-01-01

    , breastfeeding should be encouraged for 4-6 months. In high-risk infants a documented extensively hydrolysed formula is recommended if exclusive breastfeeding is not possible for the first 4 months of life. There is no evidence for preventive dietary intervention neither during pregnancy nor lactation....... Preventive dietary restrictions after the age of 4-6 months are not scientifically documented....

  18. Prevention

    Science.gov (United States)

    ... Tips Latest Research Getting More Help Related Topics Cancer COPD Dementia Depression Diabetes Drug and Substance Abuse Falls Prevention Hearing Loss Heart Attack High Blood Pressure Nutrition Osteoporosis Shingles Skin Cancer Related News Quitting Smoking, ...

  19. Offsets in fiber-coupled diode laser hygrometers caused by parasitic absorption effects and their prevention

    Science.gov (United States)

    Buchholz, B.; Ebert, V.

    2014-07-01

    Large systematic errors in absorption spectrometers (AS) can be caused by ‘parasitic’ optical absorption (parA) outside the measurement region. In particular, calibration-free direct tunable diode laser AS (dTDLAS) can take advantage of an effective parA-compensation to provide correct absolute values. However, parA also negatively affects calibrated AS in calibration frequency and stability. A common strategy to suppress parA in TDLAS systems is to fiber-couple the light source and even the detector. However, this can be a critical approach if the TDL spectrometer is validated/calibrated under laboratory conditions in ambient humidity and used afterwards in much drier and variable conditions, for example in aircrafts. This paper shows that, e.g., ‘hermetically sealed’ butterfly packages, despite fiber coupling, can possess fixed as well as variable parA sections. Two new methods for absolute parA-quantification in dTDLAS were developed, including a novel, fiber-coupled, parA-free I0-detector for permanent parA-monitoring. Their dependences on ambient humidity/pressure and temporal behavior were studied. For the example of a 1.4 µm dTDLAS hygrometer SEALDH-II with a commercial DFB-laser module and an extractive 1.5 m path cell, we quantified the parA-induced signal offsets and their dependence on cell pressure. The conversion of parA-uncertainty into H2O signal uncertainty was studied and an updated uncertainty budget including parA-uncertainty was derived. The studies showed that parA in commercial laser modules can cause substantial, systematic concentration offsets of ≈25 ppmv fixed and ≈100 ppmv variable offsets for one meter absorption path. Applying our parA-quantification techniques these offsets could be compensated by a factor of 20 to an overall offset uncertainty of 4.5 ppmv m-1. Finally, we developed an innovative, integrated, µ-pumped closed-loop air drying unit for the parA minimization and temporal stabilization in airborne laser

  20. Low-level laser therapy in the prevention and treatment of chemotherapy-induced oral mucositis in young patients.

    Science.gov (United States)

    Abramoff, Meire Maman Fracher; Lopes, Nilza Nelly Fontana; Lopes, Luciana Almeida; Dib, Luciano Lauria; Guilherme, Arnaldo; Caran, Eliana Monteiro; Barreto, Adriana Delboni; Lee, Maria Lucia Martinho; Petrilli, Antônio Sérgio

    2008-08-01

    A pilot clinical study was conducted to evaluate the efficacy and feasibility of low-level laser therapy (LLLT) in the prevention and treatment of chemotherapy (CT)-induced oral mucositis (OM) in young patients. Besides compromising the patient's nutrition and well-being, oral mucositis represents a portal of entry into the body for microorganisms present in the mouth, which may lead to sepsis if there is hematological involvement. Oncologic treatment tolerance decreases and systemic complications may arise that interfere with the success of cancer treatment. LLLT appears to be an interesting alternative to other approaches to treating OM, due to its trophic, anti-inflammatory, and analgesic properties. Patients undergoing chemotherapy (22 cycles) without mucositis were randomized into a group receiving prophylactic laser-irradiation (group 1), and a group receiving placebo light treatment (group 2). Patients who had already presented with mucositis were placed in a group receiving irradiation for therapeutic purposes (group 3, with 10 cycles of CT). Serum granulocyte levels were taken and compared to the progression of mucositis. In group 1, most patients (73%) presented with mucositis of grade 0 (p = 0.03 when compared with the placebo group), and 18% presented with grade 1. In group 2, 27% had no OM and did not require therapy. In group 3, the patients had marked pain relief (as assessed by a visual analogue scale), and a decrease in the severity of OM, even when they had severe granulocytopenia. The ease of use of LLLT, high patient acceptance, and the positive results achieved, make this therapy feasible for the prevention and treatment of OM in young patients.

  1. Mutation breeding of Bacillus subtilis YTB4 with high yield of ...

    African Journals Online (AJOL)

    Helium-neon (He-Ne) laser irradiation is a highly efficient mutation breeding technology and is widely applied to various fields of biological science. Using Bacillus subtilis YTB4 with high yield of multienzyme complex as original strain, mutation breeding was carried out by He-Ne laser irradiation in this study. Based on the ...

  2. The Creation and Varied Applications of Educational Holograms.

    Science.gov (United States)

    Layng, Jacqueline M.

    The potential of holograms has been left virtually untapped in the field of education. A hologram can be described as a three-dimensional photographic record of the interference pattern of two superimposed beams of coherent light. Holography requires: (1) high-resolution film; (2) a laser, often a red-beamed helium neon laser; (3) optical…

  3. Nd:YAG laser in caries prevention: a clinical study; Avaliacao clinica da eficiencia do laser de Nd:YAG associado ao fluor fosfato acidulado na prevencao de caries de sulcos e fissuras de criancas e adolescentes

    Energy Technology Data Exchange (ETDEWEB)

    Boari, Heloisa Gomes Dimiranda

    2000-07-01

    The caries prevention by using laser irradiation has been investigated during the last 30 years. The Nd: YAG laser associated with acidulated phosphate fluoride has been shown as a very promising technique for enamel caries prevention. The aim of this work was to clinically evaluate the efficiency of Nd: YAG laser associated with acidulated phosphate fluoride in pit and fissure caries prevention of children and adolescents. In this work it was determined the dye that enhance the effect of Nd: YAG laser in enamel. It was selected 242 pre-molar and molar teeth from 33 children and adolescents, aged from 7 to 15 years old. The selected teeth were free from caries or decalcification marks (active white marks) to the clinical and radiographic exams. The teeth were divided into two groups: the first group was laser irradiated and their homologous remained as a control. The right side teeth were dye-assisted Nd:YAG laser irradiated. The dye solution was a moisture of dust coal and equal parts of water and alcohol. The irradiation conditions were 60 mJ/10 Hz, optical fiber in contact mode, with diameter of 300 {mu}m, resulting in an energy density of 84,9 J/cm{sup 2}. The oclusal surface of the teeth was completely irradiated, specially on the slopes and in the deepest part of the pits and fissures. This procedure was repeated three times. In the sequence it was applied the acidulated phosphate fluoride for 4 minutes. On the left side teeth - control group- only acidulated phosphate fluoride was applied for the same time. The final examination considered the presence of caries and active white marks after a period of one year. There were statistical significant differences (p < 0.01) between the lased + fluoride group and the non irradiated group. The present study concluded that the technique used in this work can be an alternative clinical method for caries prevention. (author)

  4. [Use of laser for the prevention and treatment of oral mucositis induced by radiotherapy and chemotherapy for head and neck cancer].

    Science.gov (United States)

    Muñoz-Corcuera, Marta; González-Nieto, Almudena; López-Pintor Muñoz, Rosa María

    2014-08-19

    One of the complications of radiotherapy and chemotherapy is oral mucositis. Since the low energy laser is one of the most frequently recommended interventions by authors and international societies, the aim of this study is to review the scientific evidence on the use of lasers as a preventive and therapeutic in oral mucositis associated with treatment of cancer. We performed a literature search in PubMed and The Cochrane Collaboration Library, limiting the search to the last 20 years. We finally included 29 articles that contained 30 studies. Low energy laser phototherapy seems a promising intervention in both the prevention and treatment of oral mucositis associated with cancer treatment. Virtually all studies reviewed showed good results with no adverse effects and reductions in both incidence and severity of mucositis in all types of cancer treatments. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  5. The brain-derived neurotrophic factor, nerve growth factor, neurotrophin-3, and induced nitric oxide synthase expressions after low-level laser therapy in an axonotmesis experimental model.

    Science.gov (United States)

    Gomes, Lessandra Esper Abdala; Dalmarco, Eduardo Monguilhott; André, Edison Sanfelice

    2012-11-01

    A robust body of evidence has shown that low-level laser therapy (LLLT) improves peripheral nerve regeneration. However, the biochemical background triggered in this process is not yet fully understood. The purpose of this study was to evaluate the mRNA expression of neurotrophic factors (brain-derived neurotrophic factor [BDNF], nerve growth factor [NGF], and neurotrophin-3, [NT-3]) and also an inflammatory marker (induced nitric oxide synthase [iNOS]) in an axonotmesis experimental model after low-level laser therapy. Thirty-six adult male Wistar rats (250-350 g) were subjected to right sciatic nerve crush injury, and 24 h later, the animals in the three different experimental groups (n=18) were irradiated on a daily basis with helium-neon laser (collimated HeNe laser, continuous emission, wavelength: 632.8 nm, power density: 0.5 mW/cm(2), irradiation time: 20 sec, energy density: 10 J/cm(2)) during 7, 14, and 21 consecutive days, respectively. The control group (n=18) underwent the same procedures, but with the equipment turned off. At the end of the experiments, animals were killed with an overdose of anesthesia to remove samples from the sciatic nerve lesion epicenter to determine the mRNA expression of BDNF, NGF, NT-3 and iNOS enzyme. Comparisons between groups showed that HeNe laser increased the mRNA expression of both BDNF and NGF factors after 14 days of LLLT, with peak expression at the 21st day. Increase in NT-3 mRNA expression was not observed. In addition, HeNe laser produced iNOS expression reduction, which played an important role in the inflammatory process. The reported data could have a relevant practical value because LLLT is a noninvasive procedure, and have revealed significant increase in neurotrophic factor expressions and inflammatory process reduction, opening the possibility of using LLLT as an important aid to nerve regeneration process.

  6. Influence of CO2 (10.6 μm) and Nd:YAG laser irradiation on the prevention of enamel caries around orthodontic brackets.

    Science.gov (United States)

    Seino, Priscila Yumi; Freitas, Patrícia Moreira; Marques, Márcia Martins; de Souza Almeida, Fernanda Campos; Botta, Sérgio Brossi; Moreira, Maria Stella Nunes Araújo

    2015-02-01

    One possible undesirable consequence of orthodontic therapy is the development of incipient caries lesions of enamel around brackets. The aim of this study was to compare the effects of CO2 (λ = 10.6 μm) and Nd:YAG (λ = 1,064 nm) lasers associated or not with topical fluoride application on the prevention of caries lesions around brackets. Brackets were bonded to the enamel of 65 premolars. The experimental groups (n = 13) were: G1--application of 1.23% acidulated fluoride phosphate gel (AFP, control); G2--Nd:YAG laser irradiation (0.6 W, 84.9 J/cm(2), 10 Hz, 110 μs, contact mode); G3--Nd:YAG laser irradiation associated with AFP; G4--CO2 laser irradiation (0.5 W, 28.6 J/cm(2), 50 Hz, 5 μs, and 10 mm focal distance); and G5--CO2 laser irradiation associated with AFP. Quantitative light-induced fluorescence was used to assess enamel demineralization. The data were statistically compared (α = 5%). The highest demineralization occurred in the Nd:YAG laser group (G2, 26.15% ± 1.94). The demineralization of all other groups was similar to that of the control group. In conclusion, CO2 laser alone was able to control enamel demineralization around brackets at the same level as that obtained with topical fluoride application.

  7. Prevention

    Science.gov (United States)

    ... Protection Equipment (PPE) Sequence for Putting on Personal Protection Equipment (PPE) [PDF – 2.85MB] Select Your PPE Equipment Combination Guidance ... PDF, DOC, PPT, MPEG) on this site? Adobe PDF file Microsoft PowerPoint file Microsoft Word ... last updated: May 11, 2015 Content Source: Centers for Disease Control and Prevention National Center ...

  8. A prospective randomized controlled study of oral tranexamic acid for preventing postinflammatory hyperpigmentation after Q-switched ruby laser.

    Science.gov (United States)

    Kato, Harunosuke; Araki, Jun; Eto, Hitomi; Doi, Kentaro; Hirai, Rintaro; Kuno, Shinichiro; Higashino, Takuya; Yoshimura, Kotaro

    2011-05-01

    Postinflammatory hyperpigmentation (PIH) is the most common skin complication in Asians after invasive cosmetic treatments. To determine whether oral tranexamic acid (TA) reduces the incidence of PIH after Q-switched ruby laser (QSRL) treatment. Thirty-two Japanese women underwent QSRL treatment for senile lentigines on the face. They were randomly divided into two groups that did (n=15) and did not (n=17) receive oral TA treatment (750 mg/d) for the first 4 weeks after QSRL treatment. Nineteen participants had melasma-like maculae at baseline. Clinical and colorimetric assessments were performed at baseline and 2 and 4 weeks later. Pigmentation was effectively treated using QSRL at 2 weeks, but PIH was frequently seen at 4 weeks. There was no significant difference in the incidence of PIH between participants who received oral TA and those who did not. The presence of melasma did not influence the effectiveness of the treatment. Although oral TA has been reported to have depigmentation effects, it may not be effective for preventing PIH after QSRL. Considering the dosage and duration of treatment, an optimal protocol may be needed to induce the efficacy of this treatment to achieve the PIH-preventing effect of oral TA. © 2011 by the American Society for Dermatologic Surgery, Inc.

  9. DNA damage in wounded, hypoxic and acidotic human skin fibroblast cell cultures after low laser irradiation

    Science.gov (United States)

    Hawkins Evans, D.; Mbene, A.; Zungu, I.; Houreld, N.; Abrahamse, H.

    2009-02-01

    Phototherapy has become more popular and widely used in the treatment of a variety of medical conditions. To ensure sound results as evidence of its effectiveness, well designed experiments must be conducted when determining the effect of phototherapy. Cell culture models such as hypoxic, acidotic and wounded cell cultures simulating different disease conditions including ischemic heart disease, diabetes and wound healing were used to determine the effect of laser irradiation on the genetic integrity of the cell. Even though phototherapy has been found to be beneficial in a wide spectrum of conditions, it has been shown to induce DNA damage. However, this damage appears to be repairable. The risk lies in the fact that phototherapy may help the medical condition initially but damage DNA at the same time leaving undetected damage that may result in late onset, more severe, induced medical conditions including cancer. Human skin fibroblasts were cultured and used to induce a wound (by the central scratch model), hypoxic (by incubation in an anaerobic jar, 95% N2 and 5% O2) and acidotic (reducing the pH of the media to 6.7) conditions. Different models were irradiated using a Helium-Neon (632.8 nm) laser with a power density of 2.07 mW/cm2 and a fluence of 5 J/cm2 or 16 J/cm2. The effect of the irradiation was determined using the Comet assay 1 and 24 h after irradiation. In addition, the Comet assay was performed with the addition of formamidopyrimidine glycosylase (FPG) obviating strand brakes in oxidized bases at a high fluence of 16 J/cm2. A significant increase in DNA damage was seen in all three injured models at both 1 and 24 h post-irradiation when compared to the normal un-injured cells. However, when compared to non-irradiated controls the acidotic model showed a significant decrease in DNA damage 24 h after irradiation indicating the possible induction of cellular DNA repair mechanisms. When wounded cells were irradiated with higher fluences of 16 J/cm2

  10. Low-level laser therapy prevents severe oral mucositis in patients submitted to hematopoietic stem cell transplantation: a randomized clinical trial.

    Science.gov (United States)

    Ferreira, Betânia; da Motta Silveira, Fabiana Moura; de Orange, Flávia Augusta

    2016-03-01

    The purpose of this study is to evaluate the effectiveness of low-level laser therapy for the prevention of oral mucositis in patients undergoing hematopoietic stem cell transplantation. This is a randomized, parallel, superiority trial including 35 patients divided into the following: laser (n = 17) and sham (n = 18). The variables assessed were oral mucositis (grade 2 of the World Health Organization oral toxicity scale), severe oral mucositis (grade 3 or 4), and pain (according to a visual analogue scale). In the laser group, a InGaAlP laser, wavelength of 650 nm, power 100 mW, energy per point of 2 J, time 20 s by point, extremity fiber optic 0.028 cm(2), and energy density 70 J/cm(2), was used, applied the first day of conditioning until D + 5, while the sham group received simulated laser over the same period. No statistically significant difference was found in the incidence of oral mucositis (p = 0.146). Severe mucositis was found in 40% of the patients (14/35), 3 in the intervention group (17.65%) and 11 in the sham group (61.11%) (p = 0.015). The cumulative probability of survival with respect to the development of severe oral mucositis was >0.6 for the intervention group and 0 for the control group (p = 0.0397). On the day on which pain was considered the worst, patients in the sham group were more likely to classify their pain as severe compared to those in the laser group (p = 0.041). Low-level laser therapy proved effective for the prevention of severe oral mucositis and intense oral pain in patients submitted to hematopoietic stem cell transplantation.

  11. Efficacy of He-Ne Laser in the prevention and treatment of radiotherapy-induced oral mucositis in oral cancer patients.

    Science.gov (United States)

    Arora, Honey; Pai, Keerthilatha M; Maiya, Arun; Vidyasagar, M S; Rajeev, A

    2008-02-01

    The objective of this study was to evaluate the efficacy of low-level lasers for the prevention and treatment of radiotherapy-induced oral mucositis in oral cancer patients. Twenty-four hospitalized patients with oral cancer, scheduled to undergo radiotherapy at KMC, Manipal, were enrolled in the present study and assigned to laser (Group I)/control group (Group II). They were treated using He-Ne laser (lambda = 632.8nm, output = 10 mW and energy density = 1.8 J/cm(2)). Patients were subjected to treatment using laser scanner for 8 days and subsequently were treated using laser probe at 6 anatomic sites in the oral cavity for 5 minutes each. The patients were evaluated on each day of treatment for pain severity (NRS), functional impairment (FIS), and oral mucositis (RTOG) and were followed until the end of cancer treatment. Statistical analysis was done using SPSS version 10. Laser therapy applied prophylactically during radiotherapy can reduce the severity of oral mucositis, severity of pain, and functional impairment.

  12. Physics of the Brain. Prevention of the Epileptic Seizures by the Multi-photon Pulsed-operated Fiber Lasers in the Ultraviolet Range of Frequencies.

    Science.gov (United States)

    Stefan, V. Alexander; IAPS Team

    The novel study of the epileptogenesis mechanisms is proposed. It is based on the pulsed-operated (amplitude modulation) multi-photon (frequency modulation) fiber-laser interaction with the brain epilepsy-topion (the epilepsy onset area), so as to prevent the excessive electrical discharge (epileptic seizure) in the brain. The repetition frequency, Ω, matches the low frequency (epileptic) phonon waves in the brain. The laser repetition frequency (5-100 pulses per second) enables the resonance-scanning of the wide range of the phonon (possible epileptic-to-be) activity in the brain. The tunable fiber laser frequencies, Δω (multi photon operation), are in the ultraviolet frequency range, thus enabling monitoring of the electrical charge imbalance (within the 10s of milliseconds), and the DNA-corruption in the epilepsy-topion, as the possible cause of the disease. Supported by Nikola Tesla Labs., Stefan University.

  13. Free-solution, label-free molecular interactions studied by back-scattering interferometry

    DEFF Research Database (Denmark)

    Bornhop, D.J.; Latham, J.C.; Kussrow, A.

    2007-01-01

    Free-solution, label-free molecular interactions were investigated with back-scattering interferometry in a simple optical train composed of a helium-neon laser, a microfluidic channel, and a position sensor. Molecular binding interactions between proteins, ions and protein, and small molecules...

  14. Multiple wavelength illumination in flow cytometry using a single arc lamp and a dispersing element

    NARCIS (Netherlands)

    de Grooth, B.G.; van Dam, M.; Swart, N.C.; Willemsen, A.; Greve, Jan

    1987-01-01

    The principle of a multiple wavelength illumination method for flow cytometers, based upon a combination of a helium-neon laser and an arc lamp as illumination sources is described. By using a prism, the light from the arc lamp is dispersed and the different colors are imaged at different places on

  15. JPRS Report, China

    Science.gov (United States)

    1991-02-25

    strengthen the procurement the blockade sooner, come to grief by doing so late, and and sales of local products in an attempt to protect the suffer...a multi-purpose electromag- netic valve, a helium neon laser acupuncture instrument, [Article by staff reporters Chen Xiaowei (7115 2556 and a

  16. Low-level laser therapy for the prevention of low salivary flow rate after radiotherapy and chemotherapy in patients with head and neck cancer.

    Science.gov (United States)

    Gonnelli, Fernanda Aurora Stabile; Palma, Luiz Felipe; Giordani, Adelmo José; Deboni, Aline Lima Silva; Dias, Rodrigo Souza; Segreto, Roberto Araújo; Segreto, Helena Regina Comodo

    2016-01-01

    To determine whether low-level laser therapy can prevent salivary hypofunction after radiotherapy and chemotherapy in head and neck cancer patients. We evaluated 23 head and neck cancer patients, of whom 13 received laser therapy and 10 received clinical care only. An InGaAlP laser was used intra-orally (at 660 nm and 40 mW) at a mean dose of 10.0 J/cm(2) and extra-orally (at 780 nm and 15 mW) at a mean dose of 3.7 J/cm(2), three times per week, on alternate days. Stimulated and unstimulated sialometry tests were performed before the first radiotherapy and chemotherapy sessions (N0) and at 30 days after the end of treatment (N30). At N30, the mean salivary flow rates were significantly higher among the laser therapy patients than among the patients who received clinical care only, in the stimulated and unstimulated sialometry tests (p = 0.0131 and p = 0.0143, respectively). Low-level laser therapy, administered concomitantly with radiotherapy and chemotherapy, appears to mitigate treatment-induced salivary hypofunction in patients with head and neck cancer.

  17. Low-level laser therapy for the prevention of low salivary flow rate after radiotherapy and chemotherapy in patients with head and neck cancer

    Energy Technology Data Exchange (ETDEWEB)

    Gonnelli, Fernanda Aurora Stabile [Faculdades Metropolitanas Unidas (FMU), Sao Paulo, SP (Brazil); Palma, Luiz Felipe; Giordani, Adelmo Jose; Dias, Rodrigo Souza; Segreto, Roberto Araujo; Segreto, Helena Regina Comodo [Universidade Federal de Sao Paulo (EPM/UNIFESP), Sao Paulo, SP (Brazil). Escola Paulista de Medicina; Deboni, Aline Lima Silva

    2016-03-15

    Objective: to determine whether low-level laser therapy can prevent salivary hypofunction after radiotherapy and chemotherapy in head and neck cancer patients. Materials and methods: ee evaluated 23 head and neck cancer patients, of whom 13 received laser therapy and 10 received clinical care only. An InGaAlP laser was used intra-orally (at 660 nm and 40 mW) at a mean dose of 10.0 J/cm{sup 2} and extra-orally (at 780 nm and 15 mW) at a mean dose of 3.7 J/cm{sup 2} , three times per week, on alternate days. Stimulated and unstimulated sialometry tests were performed before the first radiotherapy and chemotherapy sessions (NO) and at 30 days after the end of treatment (N30). Results: At N30, the mean salivary flow rates were significantly higher among the laser therapy patients than among the patients who received clinical care only, in the stimulated and unstimulated sialometry tests (p = 0.0131 and p = 0.0143, respectively). Conclusion: low-level laser therapy, administered concomitantly with radiotherapy and chemotherapy, appears to mitigate treatment induced salivary hypofunction in patients with head and neck cancer. (author)

  18. Low-level laser therapy for the prevention of low salivary flow rate after radiotherapy and chemotherapy in patients with head and neck cancer*

    Science.gov (United States)

    Gonnelli, Fernanda Aurora Stabile; Palma, Luiz Felipe; Giordani, Adelmo José; Deboni, Aline Lima Silva; Dias, Rodrigo Souza; Segreto, Roberto Araújo; Segreto, Helena Regina Comodo

    2016-01-01

    Objective To determine whether low-level laser therapy can prevent salivary hypofunction after radiotherapy and chemotherapy in head and neck cancer patients. Materials and Methods We evaluated 23 head and neck cancer patients, of whom 13 received laser therapy and 10 received clinical care only. An InGaAlP laser was used intra-orally (at 660 nm and 40 mW) at a mean dose of 10.0 J/cm2 and extra-orally (at 780 nm and 15 mW) at a mean dose of 3.7 J/cm2, three times per week, on alternate days. Stimulated and unstimulated sialometry tests were performed before the first radiotherapy and chemotherapy sessions (N0) and at 30 days after the end of treatment (N30). Results At N30, the mean salivary flow rates were significantly higher among the laser therapy patients than among the patients who received clinical care only, in the stimulated and unstimulated sialometry tests (p = 0.0131 and p = 0.0143, respectively). Conclusion Low-level laser therapy, administered concomitantly with radiotherapy and chemotherapy, appears to mitigate treatment-induced salivary hypofunction in patients with head and neck cancer. PMID:27141130

  19. Effects of the low-intensity laser therapy on the prevention of dental caries induced in rats; Efeitos da radiacao laser em baixa intensidade na prevencao de carie dental induzida em ratos

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Karin Praia

    2004-07-01

    The purpose of this study was to investigate the effects of low intensity laser therapy, associated or not to an acidulated phosphate fluoride, on the prevention of dental caries induced in rats. It was used 40 wistar rats, female, weaned with 18 days, fed with a cariogenic diet during 48 days and inoculated orally with Streptococcus mutans by three consecutive days starting from the second day of the diet. On the fifth day of experiment the animals were divided into five groups: G{sub c} (control) the animas were no submitted to any treatment; G{sub L} (laser) irradiation with low power laser (GaAlAs, {lambda}=660 nm, P=30 mW, {delta}t=5 sec, 5 J/cm{sup 2}); G{sub F} (fluoride) topical application of acidulated phosphate fluoride (APF 1,23%) for four minutes; G{sub LF} (laser + fluoride) irradiation with low power laser followed by topical application of acidulated phosphate fluoride; G{sub FL} (fluoride + laser) topical application of acidulated phosphate fluoride followed by low power laser. The animals were sacrificed after 48 days; the molars were extracted and prepared to determine the dental caries lesions area by optical microscopy, enamel microhardness and analysis of the calcium and phosphorus ratio (Ca/P) by energy dispersive spectroscopy. The results were statistically analyzed by ANOVA (plaser radiation associated with acidulated phosphate fluoride reduces the caries area and could be an alternative in the prevention of the dental caries. (author)

  20. Laser accidents: Being Prepared

    Energy Technology Data Exchange (ETDEWEB)

    Barat, K

    2003-01-24

    The goal of the Laser Safety Officer and any laser safety program is to prevent a laser accident from occurring, in particular an injury to a person's eyes. Most laser safety courses talk about laser accidents, causes, and types of injury. The purpose of this presentation is to present a plan for safety offices and users to follow in case of accident or injury from laser radiation.

  1. Disturbance of visual functions as a result of temporary blinding from low power lasers

    Science.gov (United States)

    Reidenbach, Hans-Dieter

    2010-04-01

    Although it is well-known that dazzle, flash-blindness and afterimages may be caused by bright optical radiation, only sparse quantitative data are available with regard to the effects arising from low power laser products. Indirect effects like temporary blinding might result in serious incidents or even accidents due to the alteration of visual functions like visual acuity, contrast sensitivity and color discrimination. In order to determine the degree and duration of impairment resulting from dazzle, flash-blindness and afterimages, caused by a laser beam, an investigation has been performed with the goal to improve the current knowledge as far as especially the visual acuity recovery duration is concerned. Two different test set-ups were designed and applied in order to determine the afterimage duration and the recovery time for visual acuity after temporary blinding from a laser, respectively. In order to get the desired information a helium-neon laser was mounted on a movable assembly where the respective beam position and direction could be set up on a semicircle. In addition the mount could be inclined in a vertical plane in order to increase the variability of feasible settings. The power was adjusted in several steps in order to investigate the respective dependence of the afterimage. The investigations were relatively time consuming, since re-adaptation of about half an hour was necessary after every exposure in order not to falsify the results. The trials have been done with several volunteers in the laboratory. After the experimental mapping of the local afterimage duration for the various sites on the retina the foveal afterimage duration taf,fv produced by a red laser beam was determined. The investigations have shown a strong dependence on the angle between the line of sight and the beam direction. Besides a maximum of 300 s the dose relationship taf,fv/s ~ 50.6•ln[(P•texp)/μJ] - 13.4 for laser output powers P between 10 μW and 30 μW with

  2. A phase III randomized double-blind placebo-controlled clinical trial to determine the efficacy of low level laser therapy for the prevention of oral mucositis in patients undergoing hematopoietic cell transplantation.

    Science.gov (United States)

    Schubert, Mark M; Eduardo, Fernanda P; Guthrie, Katherine A; Franquin, Jean-Claude; Bensadoun, Rene-Jean J; Migliorati, Cesar A; Lloid, C Michele E; Eduardo, Carlos P; Walter, Niccoli-Filho; Marques, Marcia M; Hamdi, Mohd

    2007-10-01

    Oral mucositis (OM) is a significant early complication of hematopoietic cell transplantation (HCT). This phase III randomized double-blind placebo-controlled study was designed to compare the ability of 2 different low level GaAlAs diode lasers (650 nm and 780 nm) to prevent oral mucositis in HCT patients conditioned with chemotherapy or chemoradiotherapy. Seventy patients were enrolled and randomized into 1 of 3 treatment groups: 650 nm laser, 780 nm laser or placebo. All active laser treatment patients received daily direct laser treatment to the lower labial mucosa, right and left buccal mucosa, lateral and ventral surfaces of the tongue, and floor of mouth with energy densities of 2 J/cm2. Study treatment began on the first day of conditioning and continued through day +2 post HCT. Mucositis and oral pain was measured on days 0, 4, 7, 11, 14, 18, and 21 post HCT. The 650 nm wavelength reduced the severity of oral mucositis and pain scores. Low level laser therapy was well-tolerated and no adverse events were noted. While these results are encouraging, further study is needed to truly establish the efficacy of this mucositis prevention strategy. Future research needs to determine the effects of modification of laser parameters (e.g., wavelength, fluence, repetition rate of energy delivery, etc.) on the effectiveness of LLE laser to prevent OM.

  3. EFFECT OF TOPICAL BRIMONIDINE 0.15% VERSUS TIMOLOL 0.5% TO PREVENT INTRAOCULAR PRESSURE ELEVATION AFTER Nd-YAG LASER CAPSULOTOMY

    Directory of Open Access Journals (Sweden)

    Amruth Lal Yellamelli

    2017-07-01

    Full Text Available ROUND Posterior capsular opacification (PCO is the most common long term complication of modern extra capsular cataract surgery techniques including phacoemulsification. The treatment of choice for clinically significant posterior capsule opacification is Neodymium: Yttrium-Aluminium-Garnet (Nd:YAG laser posterior capsulotomy. Increased IOP is a well-known complication of Nd:YAG laser posterior capsulotomy Effective prophylaxis could prevent the possible optic nerve damage or visual field loss in susceptible patients. MATERIALS AND METHODS This prospective randomized study was conducted for one year in the Department of Ophthalmology Christian Medical College and Hospital, Ludhiana. All patients undergoing laser capsulotomy during this period were randomly distributed into two groups – A or B. Group A received 1 drop of Brimonidine 0.15%, Group B received 1 drop of 0.5% Timolol, one hour prior to presentation. Nd:YAG laser Capsulotomy was done. IOP was measured using an applanation tonometer after 1 hr, 2 hrs, 3 hrs and 4 hrs. after completion of procedure. The data was collected as per protocol and statistically analysed using t-test, Chisquare test and Z test. RESULTS There were 30 patients in each group. The baseline IOP was 15.10 ± 2.66 mmHg for group A and 16 ± 2.18 mmHg for group B (p = 0.11 (t test. There was no statistically significant reduction between the two groups in the mean IOP changes at 1, 2 or 3 hrs after Nd:YAG capsulotomy. The mean reduction in IOP after 4 hrs. for group was -1.83 mmHg and for group B was - 1.53 mmHg. The difference was statistically significant (p <0.05. CONCLUSION Brimonidine 0.15% was found to have an efficacy comparable to that of Timolol 0.5% in preventing post Nd:YAG capsulotomy IOP spikes.

  4. Photo activated disinfection efficiency of low-intensity laser and comprehensive prevention of caries and gingivitis in adolescents using bracket system

    Directory of Open Access Journals (Sweden)

    Dmitry Ye. Suetenkov

    2015-05-01

    Full Text Available It is very important to study the problem of caries and gingivitis in adolescents who are being treated for orthodontic pathology with bracket systems. The method of combined treatment which incorporates the use of medicine and laser therapy has been proved effective in caries prevention. This research aims to study clinical aspects of the effectiveness of the combined influence of the low-intensity laser "OPTODAN" with a wavelength of 0.85 μm (Scientific Development and Production Center "VEND", Saratov, Russia in caries prevention. The research also aims to study the disinfection method of PAD with "FotoSan" ("CMS Dental", Denmark, with a wavelength of 625–635 nm, where toluidine blue is used as photosensitizer molecules combined with regular measure to prevent gingivitis in adolescents being treated for orthodontic pathology with bracket systems. This paper presents the results of 1.5 years of clinical study of 60 12–13-year-old children. They were examined before and after the orthodontic treatment: their decayed, missing, filled teeth (DMFT, decayed, missing, filled tooth surfaces (DMFS index and hygiene status (OHI-S were calculated, gum inflammations were detected. Before the orthodontic treatment, their mouths were sanitized. After orthodontic appliances were placed, the children were randomly divided into two groups of 30 each. Children of the first group, while being treated with braces, took traditional preventative measures against gum inflammation and caries: occupational hygiene, local antiseptics (0.05% chlorhexidine solution, the use of remineralizing and phosphorus containing applications four times a year. The children of the second group, along with the traditional scheme of preventive measures, were treated with the devices "FotoSan" and "Optodan". Results of clinical examination of the second group have accurately proved decrease in the growth of dental caries intensity and surface caries intensity (ΔDMFT, ΔDMFS and

  5. Arabin cervical pessary for prevention of preterm birth in cases of twin-to-twin transfusion syndrome treated by fetoscopic LASER coagulation: the PECEP LASER randomised controlled trial.

    Science.gov (United States)

    Rodó, Carlota; Arévalo, Sílvia; Lewi, Liesbeth; Couck, Isabel; Hollwitz, Bettina; Hecher, Kurt; Carreras, Elena

    2017-08-01

    Fetoscopic LASER coagulation of the placental anastomoses has changed the prognosis of twin-twin transfusion syndrome. However, the prematurity rate in this cohort remains very high. To date, strategies proposed to decrease the prematurity rate have shown inconclusive, if not unfavourable results. This is a randomised controlled trial to investigate whether a prophylactic cervical pessary will lower the incidence of preterm delivery in cases of twin-twin transfusion syndrome requiring fetoscopic LASER coagulation. Women eligible for the study will be randomised after surgery and allocated to either pessary or expectant management. The pessary will be left in place until 37 completed weeks or earlier if delivery occurs. The primary outcome is delivery before 32 completed weeks. Secondary outcomes are a composite of adverse neonatal outcome, fetal and neonatal death, maternal complications, preterm rupture of membranes and hospitalisation for threatened preterm labour. 352 women will be included in order to decrease the rate of preterm delivery before 32 weeks' gestation from 40% to 26% with an alpha-error of 0.05 and 80% power. The trial aims at clarifying whether the cervical pessary prolongs the pregnancy in cases of twin-twin transfusion syndrome regardless of cervical length at the time of fetoscopy. ClinicalTrials.gov Identifier: NCT01334489 . Registered 04 December 2011.

  6. Development of oral mucositis model induced by radiation in hamsters: prevention and treatment with low power laser

    Energy Technology Data Exchange (ETDEWEB)

    Galletta, Vivian C.; Folgosi-Correa, Melissa S.; Zezell, Denise M., E-mail: vivian.galletta@gmail.com, E-mail: melfolgosi@gmail.com, E-mail: zezell@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Gouw-Soares, Sheila, E-mail: sheilagouw@hotmail.com [Universidade Cruzeiro do Sul (UNICSUL), Sao Paulo, SP (Brazil). Fac. de Odontologia; Correa, Luciana, E-mail: lcorrea@usp.br [Universidade de Sao Paulo (FO/USP), SP (Brazil). Fac. de Odontologia

    2013-07-01

    Despite the benefits for the prognosis of patients treated with radiotherapy for oral cancer treatment, it might cause local side effects such as oral mucositis. The oral mucositis is a pathological condition that may appear in affected oral mucosa by ionizing radiation, and the pain related can alter and even stop the antineoplastic treatment, decreasing tumor control rates. Oral mucositis has several treatment modalities, although it remains as a problem since therapies available are not enough to treat efficiently this inflammatory process. Many pharmacological solutions (anti-inflammatory, antibiotics, antiseptic, lubricant agents) are used to alleviate oral mucositis symptoms. Laser treatment has been used as an option, but there is lack of studies to verify the process of laser therapy in oral mucositis caused by ionizing radiation. This work accomplishes follow-up of oral mucositis evolution, comparing laser and benzydamine therapies in an animal model. Forty-two animals were irradiated at head and neck in a single dose of 30 Grays, by means of a Co{sup 60} source. After irradiation, treatments were applied daily, once a day, for 20 days, in which severity of lesions were clinically classified by two calibrated examiners. Histological evaluation was performed to search for mucosal alterations at treated tissues. Statistical analysis of data showed that laser treatment was more efficient than benzydamine treatment, diminishing severity and duration of oral mucosal lesions caused by ionizing irradiation. (author)

  7. The prevention of induced oral mucositis with low-level laser therapy in bone marrow transplantation patients: a randomized clinical trial.

    Science.gov (United States)

    Silva, Geisa Badauy Lauria; Mendonça, Elismauro Francisco; Bariani, Cesar; Antunes, Heliton Spindola; Silva, Maria Alves Garcia

    2011-01-01

    Patients who have received high doses of chemotherapy, either alone or in combination with total body irradiation often cite oral mucositis (OM) as the most debilitating side effect. The aim of this study was to investigate the clinical effects of low-level laser therapy (LLLT) on the prevention of conditioning-induced OM in hematopoietic stem cell transplantation (HSCT). We randomized 42 patients who underwent autologous or allogeneic HSCT. A low-level InGaAlP diode laser was used, emitting light at 660 nm, 40 mW, and 4 J/cm(2). An evaluation of OM was carried out using the World Health Organization scale. In the LLLT group, 57.1% of patients had an OM grade 0, 9.6% had grade 1, and 33.3% had grade 2, whereas in the control group, only 4.8% of patients were free of OM (grade 0). Our results indicate that the preventive use of LLLT in patients who have undergone HSCT is a powerful instrument in reducing OM incidence.

  8. Mid-IR laser absorption diagnostics for hydrocarbon vapor sensing in harsh environments

    Science.gov (United States)

    Klingbeil, Adam Edgar

    Fuel/air stoichiometry is an important parameter in modern combustion devices because it has a profound influence on efficiency, power, and pollutant formation. As engine technologies continue to advance, diagnostics and sensors are becoming essential for studying fundamental combustion processes and characterizing performance of combustion-based engines. Optical-absorption diagnostics have been used previously to probe various species in these environments and to infer quantities such as concentration, temperature, pressure, and velocity. However, there have been only a limited number of demonstrations of optical diagnostics for hydrocarbon fuels. This thesis describes the development of mid-IR optical-absorption sensors for time-resolved measurements of hydrocarbon species to infer critical parameters such as concentration and temperature. These sensors provide the necessary sensitivity and time resolution for measurements in shock tubes, pulse detonation engines, and internal combustion engines. Different aspects of the research conducted are summarized below. An FTIR spectrometer is used to measure the temperature-dependent absorption spectra of a selection of hydrocarbon species and blended fuels in the ˜3.3 mum region of the fundamental C-H stretching vibration. This spectroscopic library provides the first high-temperature spectral information for many of the species studied and facilitates development of sensitive diagnostics for various applications. This unique database also enables modelling of the absorption spectra of blended fuels such as gasoline. An ethylene and propane diagnostic is designed for measuring fuel concentration in a pulse detonation engine using a fixed-wavelength helium-neon laser. Time-resolved measurements during fired tests of a repetitively pulsed engine reveal non-ideal cycle-to-cycle interactions that cause a substantial amount of fuel to leave the engine unburned. By quantifying the fuel loading and identifying the amount of

  9. Lithium niobate Q-switch to prevent pre-lasing of high gain lasers operating over a wide temperature range

    Science.gov (United States)

    Jundt, Dieter H.; MacKay, Peter E.

    2015-02-01

    Because of its ease of growth and large electro-optic effect, lithium niobate is the preferred choice for Q-switching mobile lasers. Temperature-induced pyro-electric charges however may lead to premature lasing. We manufactured and characterized temperature-stable LN Q-switch. A thermo-chemical anneal was performed creating a conductive material layer 0.5mm thick with increased conductivity. While this increases optical insertion loss by a few percent, this is tolerable in high gain lasers. We present details of treatment, the surface charge creation and dissipation mechanism and the setup used to assess the cold-performance used to demonstrate improved charge dissipation when compared to untreated crystals.

  10. Microstructure and mechanical changes induced by Q-Switched pulse laser on human enamel with aim of caries prevention

    Science.gov (United States)

    Apsari, R.; Pratomo, D. A.; Hikmawati, D.; Bidin, N.

    2016-03-01

    This study was conducted to determine the effect of Q-Switched Nd: YAG laser energy dose to human enamel caries. The specifications of Q-Switched Nd: YAG laser as followed: wavelength of 1064 nm and 6 ns pulse width. Caries enamel samples taken from human teeth molars of 17-35 ages and the type of media caries. Energy doses used in this study were 723.65 mJ/cm2, 767.72 mJ/cm2, and 1065.515 mJ/cm2; 5 Hz repetition rate, and 20 second exposure time. Samples characterized the surface morphology and the percentage of constituent elements, especially calcium/phosphorus (Ca/P) with FESEM-EDAX. The fraction volume and crystallinity percentage of hydroxyapatite (HA) with XRD and hardness value using Vickers Microhardness Test. The results indicated that exposure of Q-Switched Nd:YAG laser on enamel caries resulting cracks, holes, and melt due to plasma production effects in the surface. Plasma production effect also resulted in micro properties such as percentage of Ca/P was close to normal, the fraction volume and crystallinity percentage of HA went up but did not change the crystal structure (in terms of the lattice structure). The hardness value also rose as linear as exposure energy dose caused by phototermal effect. Based on the results, Q-Switched Nd:YAG laser can be used as contactless drill dental caries replacement candidate with the additional therapy effect such as localized caries in order to avoid the spread, the ratio of Ca/P approaching healthy teeth, the fraction volume and crystallinity percentage of HA rose and established stronger teeth with peak energy dose 1065.515 mJ/cm2.

  11. Effect of type of cavity preparation (bur,Er:YAG laser and restorative materials on prevention of caries lesion

    Directory of Open Access Journals (Sweden)

    Masumeh Hasani Tabatabaei

    2017-03-01

    Full Text Available Background and Aims: Despite the reduction of incidence of dental caries in recent years, this disease is common and many efforts were conducted to decrease the prevalence of dental caries. On the other hand secondary caries lesions are the main reason for replacement of direct restorations. Therefore, the aim of the current study was to evaluate suitable methods of preparation and restorative materials to reduce caries recurrence. Materials and Methods: In this experimental study, eighty human teeth were collected and stored in normal saline. The teeth were soft-tissue debrided and cleaned with water/pumice slurry and rubber cups in a low-speed handpiece. Speciments were randomly divided in two main groups. Cavities were prepared with diamond burs or Er:YAG laser (10 Hz, 300 mJ, 3W. Each group was divided into 4 sub-groups, and restored with a glass-ionomer cement (Fuji IX, resin modified glass-ionomer (Fuji II LC, total etch bonding + composite resin or self-etch bonding + composite resin. The specimens were submitted to pH cycling. Speciments were then sectioned, polished and Vickers microhardness measurements were performed on each specimen. Differences among the medians were analyzed using two way ANOVA test at a 95% confidence level and Tukey test. Results: Statistical analysis showed significant difference in the type of substrate (enamel, dentin in both main groups (P<0.0001 but no differences in the caries lesion development between the cavities restored with the same material and prepared with diamond burs or Er:YAG laser. Conclusion: The Er:YAG laser used for cavity preparation and different types of restorative materials used did not show the ability to guarantee significantly more acid-resistance tooth structure against demineralization.

  12. Evaluation of Enterococcus faecalis adhesion, penetration, and method to prevent the penetration of Enterococcus faecalis into root cementum: Confocal laser scanning microscope and scanning electron microscope analysis.

    Science.gov (United States)

    Halkai, Rahul S; Hegde, Mithra N; Halkai, Kiran R

    2016-01-01

    To ascertain the role of Enterococcus faecalis in persistent infection and a possible method to prevent the penetration of E. faecalis into root cementum. One hundred and twenty human single-rooted extracted teeth divided into five groups. Group I (control): intact teeth, Group II: no apical treatment done, Group III divided into two subgroups. In Groups IIIa and IIIb, root apex treated with lactic acid of acidic and neutral pH, respectively. Group IV: apical root cementum exposed to lactic acid and roughened to mimic the apical resorption. Group V: apical treatment done same as Group IV and root-end filling done using mineral trioxide aggregate (MTA). Apical one-third of all samples immersed in E. faecalis broth for 8 weeks followed by bone morphogenetic protein and obturation and again immersed into broth for 8 weeks. Teeth split into two halves and observed under confocal laser scanning microscope and scanning electron microscope, organism identified by culture and polymerase chain reaction techniques. Adhesion and penetration was observed in Group IIIa and Group IV. Only adhesion in Group II and IIIB and no adhesion and penetration in Group I and V. Adhesion and penetration of E. faecalis into root cementum providing a long-term nidus for subsequent infection are the possible reason for persistent infection and root-end filling with MTA prevents the adhesion and penetration.

  13. Phase III trial of low-level laser therapy to prevent oral mucositis in head and neck cancer patients treated with concurrent chemoradiation.

    Science.gov (United States)

    Antunes, Heliton S; Herchenhorn, Daniel; Small, Isabele A; Araújo, Carlos M M; Viégas, Celia Maria Pais; Cabral, Elida; Rampini, Mariana P; Rodrigues, Pedro C; Silva, Tereza G P; Ferreira, Elza M S; Dias, Fernando L; Ferreira, Carlos G

    2013-11-01

    Oral mucositis (OM) is a complication of chemoradiotherapy treatment of head and neck squamous cell carcinoma (HNSCC) patients with no effective therapy. This study was designed to assess the efficacy of preventive low-level laser therapy (LLLT) in reducing the incidence of grade 3-4 OM. From June 2007 to December 2010, 94 HNSCC patients entered a prospective, randomized, double-blind, placebo-controlled phase III trial. Chemoradiotherapy consisted of conventional radiotherapy plus concurrent cisplatin every 3weeks. A diode InGaAlP (660nm-100mW-1J-4J/cm(2)) was used. OM evaluation was performed by WHO and OMAS scales and quality of life by EORTC questionnaires (QLQ). A six-fold decrease in the incidence of grades 3-4 OM was detected in the LLLT group compared to the placebo; (6.4% versus 40.5%). LLLT impacted the incidence of grades 3-4 OM to a relative risk ratio of 0.158 (CI 95% 0.050-0.498). After treatment QLQ-C30 showed, differences favoring LLLT in physical, emotional functioning, fatigue, and pain; while the QLQ-H&N35 showed improvements in LLLT arm for pain, swallowing, and trouble with social eating. Preventive LLLT in HNSCC patients receiving chemoradiotherapy is an effective tool for reducing the incidence of grade 3-4 OM. Efficacy data were corroborated by improvements seen in quality of life. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  14. Evaluation of Enterococcus faecalis adhesion, penetration, and method to prevent the penetration of Enterococcus faecalis into root cementum: Confocal laser scanning microscope and scanning electron microscope analysis

    Science.gov (United States)

    Halkai, Rahul S.; Hegde, Mithra N.; Halkai, Kiran R.

    2016-01-01

    Aim: To ascertain the role of Enterococcus faecalis in persistent infection and a possible method to prevent the penetration of E. faecalis into root cementum. Methodology: One hundred and twenty human single-rooted extracted teeth divided into five groups. Group I (control): intact teeth, Group II: no apical treatment done, Group III divided into two subgroups. In Groups IIIa and IIIb, root apex treated with lactic acid of acidic and neutral pH, respectively. Group IV: apical root cementum exposed to lactic acid and roughened to mimic the apical resorption. Group V: apical treatment done same as Group IV and root-end filling done using mineral trioxide aggregate (MTA). Apical one-third of all samples immersed in E. faecalis broth for 8 weeks followed by bone morphogenetic protein and obturation and again immersed into broth for 8 weeks. Teeth split into two halves and observed under confocal laser scanning microscope and scanning electron microscope, organism identified by culture and polymerase chain reaction techniques. Results: Adhesion and penetration was observed in Group IIIa and Group IV. Only adhesion in Group II and IIIB and no adhesion and penetration in Group I and V. Conclusion: Adhesion and penetration of E. faecalis into root cementum providing a long-term nidus for subsequent infection are the possible reason for persistent infection and root-end filling with MTA prevents the adhesion and penetration. PMID:27994316

  15. Discovery of a solvent effect preventing quantitative profiling by matrix-assisted laser desorption/ionization and its treatment.

    Science.gov (United States)

    Park, Kyung Man; Moon, Jeong Hee; Kim, Jae Hyung; Song, Un Tak; Lee, Seong Hoon; Kim, Myung Soo

    2016-02-15

    In analyte profiling by matrix-assisted laser desorption/ionization (MALDI), drawing a quantitative profile map is an outstanding problem. Recently, we developed a method to quantify an analyte by MALDI, which is needed to solve the problem. Another requirement for quantitative profiling is the quantitative sample-to-matrix analyte transfer, which is investigated in this work. MALDI-time-of-flight (TOF) spectra were acquired for samples produced by two methods. In one, a sample solution containing a matrix and an analyte was loaded with a pipet and dried. In the other, a sample was prepared by a consecutive process, i.e., loading-drying of an analyte solution followed by that of a matrix solution. Two different micro-spotters were used in the second method. Various mixtures of organic solvents with water were used to prepare matrix solutions. The organic solvent, matrix, and analyte used in the study did not affect the analyte transfer efficiency, whereas it improved as the water content in the solvent increased. It also improved as the liquid droplet emitted by a micro-spotter got larger. Use of a more polar solvent or a larger droplet increases the contact time between a solution droplet and the sample surface, which seems to be responsible for the improvement in the transfer efficiency. Sample-to-matrix analyte transfer occurred efficiently when polar solvents and/or large liquid droplets were used to produce solid samples for MALDI profiling with a micro-spotter. A long contact time between the sample surface and a matrix solution droplet is one of the requirements for quantitative profiling. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  16. Oral Mucositis Prevention By Low-Level Laser Therapy in Head-and-Neck Cancer Patients Undergoing Concurrent Chemoradiotherapy: A Phase III Randomized Study

    Energy Technology Data Exchange (ETDEWEB)

    Gouvea de Lima, Aline [Departamento de Radiologia, Disciplina de Oncologia, Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo, SP (Brazil); Villar, Rosangela Correa [Instituto de Radiologia, Servico de Radioterapia, Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo, SP (Brazil); Castro, Gilberto de, E-mail: gilberto.castro@usp.br [Department of Clinical Oncology, Instituto do Cancer do Estado de Sao Paulo, Sao Paulo, SP (Brazil); Antequera, Reynaldo [Divisao de Odontologia, Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo, SP (Brazil); Gil, Erlon; Rosalmeida, Mauro Cabral [Instituto de Radiologia, Servico de Radioterapia, Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo, SP (Brazil); Federico, Miriam Hatsue Honda; Snitcovsky, Igor Moises Longo [Departamento de Radiologia, Disciplina de Oncologia, Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo, SP (Brazil)

    2012-01-01

    Purpose: Oral mucositis is a major complication of concurrent chemoradiotherapy (CRT) in head-and-neck cancer patients. Low-level laser (LLL) therapy is a promising preventive therapy. We aimed to evaluate the efficacy of LLL therapy to decrease severe oral mucositis and its effect on RT interruptions. Methods and Materials: In the present randomized, double-blind, Phase III study, patients received either gallium-aluminum-arsenide LLL therapy 2.5 J/cm{sup 2} or placebo laser, before each radiation fraction. Eligible patients had to have been diagnosed with squamous cell carcinoma or undifferentiated carcinoma of the oral cavity, pharynx, larynx, or metastases to the neck with an unknown primary site. They were treated with adjuvant or definitive CRT, consisting of conventional RT 60-70 Gy (range, 1.8-2.0 Gy/d, 5 times/wk) and concurrent cisplatin. The primary endpoints were the oral mucositis severity in Weeks 2, 4, and 6 and the number of RT interruptions because of mucositis. The secondary endpoints included patient-reported pain scores. To detect a decrease in the incidence of Grade 3 or 4 oral mucositis from 80% to 50%, we planned to enroll 74 patients. Results: A total of 75 patients were included, and 37 patients received preventive LLL therapy. The mean delivered radiation dose was greater in the patients treated with LLL (69.4 vs. 67.9 Gy, p = .03). During CRT, the number of patients diagnosed with Grade 3 or 4 oral mucositis treated with LLL vs. placebo was 4 vs. 5 (Week 2, p = 1.0), 4 vs. 12 (Week 4, p = .08), and 8 vs. 9 (Week 6, p = 1.0), respectively. More of the patients treated with placebo had RT interruptions because of mucositis (6 vs. 0, p = .02). No difference was detected between the treatment arms in the incidence of severe pain. Conclusions: LLL therapy was not effective in reducing severe oral mucositis, although a marginal benefit could not be excluded. It reduced RT interruptions in these head-and-neck cancer patients, which might

  17. Oral mucositis prevention by low-level laser therapy in head-and-neck cancer patients undergoing concurrent chemoradiotherapy: a phase III randomized study.

    Science.gov (United States)

    Gouvêa de Lima, Aline; Villar, Rosângela Correa; de Castro, Gilberto; Antequera, Reynaldo; Gil, Erlon; Rosalmeida, Mauro Cabral; Federico, Miriam Hatsue Honda; Snitcovsky, Igor Moisés Longo

    2012-01-01

    Oral mucositis is a major complication of concurrent chemoradiotherapy (CRT) in head-and-neck cancer patients. Low-level laser (LLL) therapy is a promising preventive therapy. We aimed to evaluate the efficacy of LLL therapy to decrease severe oral mucositis and its effect on RT interruptions. In the present randomized, double-blind, Phase III study, patients received either gallium-aluminum-arsenide LLL therapy 2.5 J/cm(2) or placebo laser, before each radiation fraction. Eligible patients had to have been diagnosed with squamous cell carcinoma or undifferentiated carcinoma of the oral cavity, pharynx, larynx, or metastases to the neck with an unknown primary site. They were treated with adjuvant or definitive CRT, consisting of conventional RT 60-70 Gy (range, 1.8-2.0 Gy/d, 5 times/wk) and concurrent cisplatin. The primary endpoints were the oral mucositis severity in Weeks 2, 4, and 6 and the number of RT interruptions because of mucositis. The secondary endpoints included patient-reported pain scores. To detect a decrease in the incidence of Grade 3 or 4 oral mucositis from 80% to 50%, we planned to enroll 74 patients. A total of 75 patients were included, and 37 patients received preventive LLL therapy. The mean delivered radiation dose was greater in the patients treated with LLL (69.4 vs. 67.9 Gy, p = .03). During CRT, the number of patients diagnosed with Grade 3 or 4 oral mucositis treated with LLL vs. placebo was 4 vs. 5 (Week 2, p = 1.0), 4 vs. 12 (Week 4, p = .08), and 8 vs. 9 (Week 6, p = 1.0), respectively. More of the patients treated with placebo had RT interruptions because of mucositis (6 vs. 0, p = .02). No difference was detected between the treatment arms in the incidence of severe pain. LLL therapy was not effective in reducing severe oral mucositis, although a marginal benefit could not be excluded. It reduced RT interruptions in these head-and-neck cancer patients, which might translate into improved CRT efficacy. Copyright © 2012 Elsevier

  18. Laser in operative dentistry

    Directory of Open Access Journals (Sweden)

    E. Yasini

    1994-06-01

    Full Text Available Today laser has a lot of usage in medicine and dentistry. In the field of dentistry, laser is used in soft tissue surgery, sterilization of canals (in root canal therapy and in restorative dentistry laser is used for cavity preparation, caries removal, sealing the grooves (in preventive dentistry, etching enamel and dentin, composite polymerization and removal of tooth sensitivity. The use of Co2 lasers and Nd: YAG for cavity preparation, due to creating high heat causes darkness and cracks around the region of laser radiation. Also due to high temperature of these lasers, pulp damage is inevitable. So today, by using the Excimer laser especially the argon floride type with a wavelength of 193 nm, the problem of heat stress have been solved, but the use of lasers in dentistry, especially for cavity preparation needs more researches and evaluations.

  19. Lasers in orthodontics

    Science.gov (United States)

    Nalcaci, Ruhi; Cokakoglu, Serpil

    2013-01-01

    Many types of dental lasers are currently available that can be efficiently used for soft and hard tissue applications in the field of orthodontics. For achieving the desired effects in the target tissue, knowledge of laser characteristics such as power, wavelength and timing, is necessary. Laser therapy is advantageous because it often avoids bleeding, can be pain free, is non-invasive and is relatively quick. The high cost is its primary disadvantage. It is very important to take the necessary precautions to prevent possible tissue damage when using laser dental systems. Here, we reviewed the main types and characteristics of laser systems used in dental practice and discuss the applications of lasers in orthodontics, harmful effects and laser system safety. PMID:24966719

  20. Low-level laser therapy in the prevention of radiotherapy-induced xerostomia and oral mucositis; Prevencao da xerostomia e da musosite oral induzidas por radioterapia com uso do laser de baixa potencia

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Carlos de Oliveira [Instituto de Radioterapia do Vale do Paraiba Ltda., Sao Jose dos Campos, SP (Brazil)]. E-mail: colopes@uol.com.br; Mas, Josepa Rigau I. [Universitat Rovira i Virgili, Tarragona (Spain). Facultat Medicine i la Ciencies Salut; Zangaro, Renato Amaro [Universidade do Vale do Paraiba (UNIVAP), Sao Jose dos Campos, SP (Brazil). Inst. de Pesquisa e Desenvolvimento

    2006-03-15

    Objective: to verify if the use of InGaAIP laser with 685 nm wave length can reduce the xerostomy incidence, the oral mucositis severity and the pain related to mucositis in patients with head and neck cancer submitted to radiotherapy. Objective: sixty patients presenting head and neck carcinoma were submitted to radiotherapy with daily doses of 1.8 to 2.0 Gy and a final dose of 45 to 72 Gy. The salivary volume was evaluated in the first and fifteenth days, at the end of the treatment and after 15 and 30 days. The oral mucositis was evaluated on a weekly basis. Twenty-nine patients were submitted to radiotherapy without laser and 31 were submitted to radiotherapy and laser with daily doses of 2 joules/cm{sup 2} in predetermined areas of the oral mucosa and the parotid and submandibular glands. Results: in the group submitted to radiotherapy and laser the incidence of mucositis (p < 0.001) and pain (p < 0.016) was significantly lower and the salivary volume (p < 0.001) was kept higher during and after the treatment. Conclusion: the group of patients submitted to radiotherapy and laser had lower incidence of xerostomy, oral mucositis and pain when compared to the group treated with radiotherapy without laser, producing statistically significant results. (author)

  1. Prevenção da xerostomia e da mucosite oral induzidas por radioterapia com uso do laser de baixa potência Low level laser therapy in the prevention of radiotherapy-induced xerostomia and oral mucositis

    Directory of Open Access Journals (Sweden)

    Carlos de Oliveira Lopes

    2006-04-01

    Full Text Available OBJETIVO: Verificar se o uso do laser de InGaAlP com comprimento de onda de 685 nm pode reduzir a incidência de xerostomia, gravidade da mucosite oral e da dor associada à mucosite em pacientes portadores de câncer de cabeça e pescoço submetidos a radioterapia. MATERIAIS E MÉTODOS: Sessenta pacientes portadores de carcinoma de cabeça e pescoço foram submetidos a radioterapia com dose diária de 1,8 a 2,0 Gy e dose final de 45 a 72 Gy. O volume salivar foi medido nos dias um, 15, ao final do tratamento e após 15 e 30 dias, e a mucosite oral em avaliações semanais. Vinte e nove pacientes se submeteram a radioterapia sem laser e 31 foram submetidos a radioterapia e laser com dose diária de 2 joules/cm² em pontos pré-determinados da mucosa oral e glândulas parótida e submandibular. RESULTADOS: No grupo submetido a radioterapia e laser, a incidência de mucosite (p OBJECTIVE: To verify if the use of InGaAIP laser with 685 nm wave length can reduce the xerostomy incidence, the oral mucositis severity and the pain related to mucositis in patients with head and neck cancer submitted to radiotherapy. MATERIALS AND METHODS: Sixty patients presenting head and neck carcinoma were submitted to radiotherapy with daily doses of 1.8 to 2.0 Gy and a final dose of 45 to 72 Gy. The salivary volume was evaluated in the first and fifteenth days, at the end of the treatment and after 15 and 30 days. The oral mucositis was evaluated on a weekly basis. Twenty-nine patients were submitted to radiotherapy without laser and 31 were submitted to radiotherapy and laser with daily doses of 2 joules/cm² in predetermined areas of the oral mucosa and the parotid and submandibular glands. RESULTS: In the group submitted to radiotherapy and laser the incidence of mucositis (p < 0.001 and pain (p < 0.016 was significantly lower and the salivary volume (p < 0.001 was kept higher during and after the treatment. CONCLUSION: The group of patients submitted to

  2. Modification Of Normal Microscope To Magneto-Optical Microscope

    Directory of Open Access Journals (Sweden)

    Nurazlin Ahmad

    2015-04-01

    Full Text Available Abstract The present work reports on the modification of polarizing microscope to a magnetic domain imaging microscope based on Faraday Effect. Sample used in this research is a ferromagnetic garnet BiTmNa3FeGa5O12. The halogen lamp in the microscope is replaced by helium-neon HeNe laser as a light source. To reduce the laser spatial coherent effect thin transparent plastics placed in the laser path. The plastics are rotated at certain velocity. Other factors to be considered are the plastic rotation velocity the laser intensity and the laser alignment. Typical magnetic domain pattern is obtained with the new system.

  3. Topical 0.1% Bromfenac Sodium for Intraoperative Miosis Prevention and Prostaglandin E2 Inhibition in Femtosecond Laser-Assisted Cataract Surgery.

    Science.gov (United States)

    Chen, Hui; Lin, Haotian; Chen, Wan; Zhang, Bo; Xiang, Wu; Li, Jing; Chen, Weirong

    2017-04-01

    The purpose of this study was to evaluate the effect of topical 0.1% bromfenac sodium, a nonsteroidal anti-inflammatory drug (NSAID), on intraoperative pupil dilation maintenance and prostaglandin E2 (PGE2) inhibition during femtosecond laser-assisted cataract surgery. Sixty patients (30 each in study and control groups) were included in this study. The patients received 0.1% bromfenac ophthalmic solution or control placebo twice a day for 3 days before surgery. Pupil size was measured at the initiation of femtosecond laser pretreatment and phacoemulsification. Aqueous humor was collected at the beginning of routine cataract surgery. PGE2 levels were measured with an enzyme-linked immunoassay. Laser flare photometry was measured preoperatively and at 1 day postoperatively. Compared with untreated patients, the change in pupil size and postoperative day 1 aqueous flare were significantly reduced throughout the operation in the patients treated with 0.1% bromfenac (P miosis, and reducing PGE2 levels.

  4. The use of Intravenous Laser Blood Irradiation (ILBI) at 630–640 nm to prevent vascular diseases and to increase life expectancy

    OpenAIRE

    Mikhaylov, VA

    2015-01-01

    Background and Aims: The mortality rate from vascular diseases is one of the highest. The use of Intravenous Laser Blood Irradiation (ILBI) within the last 30 years has demonstrated high efficacy in the treatment of vascular, cardiac and other systemic diseases.

  5. Macular Burns from Nonmedical Lasers.

    Science.gov (United States)

    Sayman Muslubaş, Işıl; Hocaoğlu, Mümin; Arf, Serra; Özdemir, Hakan; Karaçorlu, Murat

    2016-06-01

    Laser devices are widely used for medical, military, industrial and entertainment purposes. This extensive and unregulated use of lasers can cause a variety of maculopathies that can result in permanent vision loss. Uncontrolled and inappropriate use of laser instruments should be prevented with strict rules. We strongly emphasize the importance of changing the general misperception that lasers are safe to use for entertainment purposes. In this study we aim to report the clinical features of three patients with a history of maculopathy caused by exposure to laser light in an entertainment venue.

  6. Macular Burns from Nonmedical Lasers

    Directory of Open Access Journals (Sweden)

    Işıl Sayman Muslubaş

    2016-06-01

    Full Text Available Laser devices are widely used for medical, military, industrial and entertainment purposes. This extensive and unregulated use of lasers can cause a variety of maculopathies that can result in permanent vision loss. Uncontrolled and inappropriate use of laser instruments should be prevented with strict rules. We strongly emphasize the importance of changing the general misperception that lasers are safe to use for entertainment purposes. In this study we aim to report the clinical features of three patients with a history of maculopathy caused by exposure to laser light in an entertainment venue.

  7. Evaluation of low-level laser therapy in the prevention and treatment of radiation-induced mucositis: a double-blind randomized study in head and neck cancer patients.

    Science.gov (United States)

    Carvalho, P A G; Jaguar, G C; Pellizzon, A C; Prado, J D; Lopes, R N; Alves, F A

    2011-12-01

    The purpose of this prospective study was to determine the effect of the low-level laser in the prevention and treatment of mucositis in head and neck cancer patients. A total of 70 patients with malignant neoplasms in the oral cavity or oropharynx were evaluated. The patients were randomized into two low-level laser therapy groups: Group 1 (660nm/15mW/3.8J/cm(2)/spot size 4mm(2)) or Group 2 (660nm/5mW/1.3J/cm(2)/spot size 4mm(2)) starting on the first day of radiotherapy. Oral mucositis was assessed daily and weekly using the NCI and WHO scales. Oral pain was scored daily with a visual analogue scale before laser application. The patients in Group 1 had a mean time of 13.5days (range 6-26days) to present mucositis grade II, while the patients in Group 2 had a mean time of 9.8days (range 4-14days) (both WHO and NCI p=0.005). In addition, Group 2 also presented a higher mucositis grade than Group 1 with significant differences found in weeks 2 (p=0.019), 3 (p=0.005) and 4 (p=0.003) for WHO scale and weeks 2 (p=0.009) and 4 (p=0.013) for NCI scale. The patients in Group 1 reported lower pain levels (p=0.004). Low-level laser therapy during radiotherapy was found to be effective in controlling the intensity of mucositis and pain. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Lasers in pediatric dentistry.

    Science.gov (United States)

    Kotlow, Lawrence A

    2004-10-01

    Pediatric dentistry's mission in delivering care to our young patients is simple: provide optimal preventive, interceptive, and restorative dental care in a stress-free environment. Lasers such as argon, diode, Nd:YAG, CO2, and now the erbium family enable minimally invasive dentistry for hard- and soft-tissue procedures. This article offers an understanding of treatment planning in the pediatric practice and demonstrates the procedures that dental lasers can perform on younger patients.

  9. Lasers technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    The Lasers Technology Program of IPEN is committed to the development of new lasers based on the research of optical materials and new technologies, as well to laser applications in several areas: Nuclear, Medicine, Dentistry, Industry, Environment and Advanced Research. The Program is basically divided into two main areas: Material and Laser Development and Laser Applications.

  10. The use of Intravenous Laser Blood Irradiation (ILBI) at 630-640 nm to prevent vascular diseases and to increase life expectancy.

    Science.gov (United States)

    Mikhaylov, V A

    2015-03-31

    The mortality rate from vascular diseases is one of the highest. The use of Intravenous Laser Blood Irradiation (ILBI) within the last 30 years has demonstrated high efficacy in the treatment of vascular, cardiac and other systemic diseases. Laser energy at 630-640 nanometers is arguably the most effective for irradiation of blood and the vascular wall. Photons at this wavelength are absorbed by oxygen, improve microcirculation, can change the viscosity of the blood and affect vascular endothelium. In summary, more than 25 years of experience of using laser energy at 630-640 nm has shown that this waveband directly influences the parameters of all cells in the blood, blood plasma, the coagulation process and all the structural components of the vascular wall. Additionally, ILBI directly or indirectly affects the cells of the immune system, hormones, and exchange processes in an organism, thereby not only improving the function of the vascular system, but also the other systems of an organism. It can finally lead to lower the incidence and number of vascular diseases, and indirectly to the reduction of the number of diseases in other organs and even systemically, thus helping to prolong the lifespan.

  11. Avaliação comparativa do efeito dos colírios de apraclonidina e latanoprost na profilaxia da hipertensão ocular pós capsulotomia com YAG Laser em pacientes não glaucomatosos Profilatic use of apraclonidine and latanoprost to prevent intraocular pressure elevation following Nd:YAG laser posterior capsulotomy

    Directory of Open Access Journals (Sweden)

    Juliane de Freitas S. Paranhos

    1999-10-01

    Full Text Available Objetivo: Comparar a eficácia do latanoprost 0,005% e da apraclonidina 1% na prevenção da hipertensão ocular pós-capsulotomia posterior com YAG laser, em pacientes não- glaucomatosos. Método: Trinta e seis pacientes (36 olhos incluídos foram divididos em três grupos que usaram latanoprost 0,005%, apraclonidina 1% ou placebo. Foram realizadas medidas da pressão ocular antes da instilação de qualquer colírio, 30 minutos após a dilatação, 1 hora e 4 horas após o YAG laser. Resultados: Não houve diferença significativa entre os 3 grupos em relação à idade, pressão ocular inicial e pós-dilatação, assim como em quantidade de energia utilizada. Na primeira hora, tanto para a diferença absoluta quanto para o percentual de alteração da pressão intra-ocular, o grupo da apraclonidina apresentou redução estatisticamente maior em relação ao grupo controle (p 0,05. Na 4a. hora não houve diferença significativa entre os grupos (p > 0,05. As medidas de pressão nos 4 intervalos não apresentaram variação estatisticamente significativa (p > 0,05. A quantidade de energia utilizada não mostrou correlação significativa com o aumento da Po (p > 0,05. Conclusão: A apraclonidina 1% apresentou maior eficácia na profilaxia da hipertensão após capsulotomia posterior com YAG laser quando comparada com latanoprost 0,005%.Purpose: To compare the efficacy of 0.005% latanoprost and 1% apraclonidine in the prevention of an increase of intraocular pressure (IOP after Nd: YAG laser capsulotomy in nonglaucomatous patients. Methods: Thirty-six patients were included and divided in to three groups. Patients received 0.005% latanoprost. 1% apraclonidine or placebo. Four measurements of IOP were made: before instillation of any drug, 30 minutes after cycloplegia, 1 hour and 4 hours after laser. Results: No significant difference was found between the three groups regarding age, initial intraocular pressure, pressure 30 minutes after

  12. Laser principles.

    Science.gov (United States)

    Bogdan Allemann, Inja; Kaufman, Joely

    2011-01-01

    Since the construction of the first laser in the 1960s, the role that lasers play in various medical specialities, including dermatology, has steadily increased. However, within the last 2 decades, the technological advances and the use of lasers in the field of dermatology have virtually exploded. Many treatments have only become possible with the use of lasers. Especially in aesthetic medicine, lasers are an essential tool in the treatment armamentarium. Due to better research and understanding of the physics of light and skin, there is now a wide and increasing array of different lasers and devices to choose from. The proper laser selection for each indication and treatment requires a profound understanding of laser physics and the basic laser principles. Understanding these principles will allow the laser operator to obtain better results and help avoid complications. This chapter will give an in-depth overview of the physical principles relevant in cutaneous laser surgery. Copyright © 2011 S. Karger AG, Basel.

  13. Influence of beam shape on in-vitro cellular transformations in human skin fibroblasts

    Science.gov (United States)

    Mthunzi, Patience; Forbes, Andrew; Hawkins, Denise; Abrahamse, Heidi; Karsten, Aletta E.

    2005-08-01

    A variety of strategies have been utilised for prevention and treatment of chronic wounds such as leg ulcers, diabetic foot ulcers and pressure sores1. Low Level Laser Therapy (LLLT) has been reported to be an invaluable tool in the enhancement of wound healing through stimulating cell proliferation, accelerating collagen synthesis and increasing ATP synthesis in mitochondria to name but a few2. This study focused on an in-vitro analysis of the cellular responses induced by treatment with three different laser beam profiles namely, the Gaussian (G), Super Gaussian (SG) and Truncated Gaussian (TG), on normal wounded irradiated (WI) and wounded non-irradiated (WNI) human skin fibroblast cells (WS1), to test their influence in wound healing at 632.8 nm using a helium neon (HeNe) laser. For each beam profile, measurements were made using average energy densities over the sample ranging from 0.2 to 1 J, with single exposures on normal wounded cells. The cells were subjected to different post irradiation incubation periods, ranging from 0 to 24 hours to evaluate the duration (time) dependent effects resulting from laser irradiation. The promoted cellular alterations were measured by increase in cell viability, cell proliferation and cytotoxicity. The results obtained showed that treatment with the G compared to the SG and TG beams resulted in a marked increase in cell viability and proliferation. The data also showed that when cells undergo laser irradiation some cellular processes are driven by the peak energy density rather than the energy of the laser beam. We show that there exist threshold values for damage, and suggest optimal operating regimes for laser based wound healing.

  14. Evaluation of Enterococcus faecalis adhesion, penetration, and method to prevent the penetration of Enterococcus faecalis into root cementum: Confocal laser scanning microscope and scanning electron microscope analysis

    OpenAIRE

    Rahul S Halkai; Hegde, Mithra N; Halkai, Kiran R.

    2016-01-01

    Aim: To ascertain the role of Enterococcus faecalis in persistent infection and a possible method to prevent the penetration of E. faecalis into root cementum. Methodology: One hundred and twenty human single-rooted extracted teeth divided into five groups. Group I (control): intact teeth, Group II: no apical treatment done, Group III divided into two subgroups. In Groups IIIa and IIIb, root apex treated with lactic acid of acidic and neutral pH, respectively. Group IV: apical root cementu...

  15. Selective laser melting porous metallic implants with immobilized silver nanoparticles kill and prevent biofilm formation by methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    van Hengel, Ingmar A J; Riool, Martijn; Fratila-Apachitei, Lidy E; Witte-Bouma, Janneke; Farrell, Eric; Zadpoor, Amir A; Zaat, Sebastian A J; Apachitei, Iulian

    2017-09-01

    Implant-associated infection and limited longevity are two major challenges that orthopedic devices need to simultaneously address. Additively manufactured porous implants have recently shown tremendous promise in improving bone regeneration and osseointegration, but, as any conventional implant, are threatened by infection. In this study, we therefore used rational design and additive manufacturing in the form of selective laser melting (SLM) to fabricate porous titanium implants with interconnected pores, resulting in a 3.75 times larger surface area than corresponding solid implants. The SLM implants were biofunctionalized by embedding silver nanoparticles in an oxide surface layer grown using plasma electrolytic oxidation (PEO) in Ca/P-based electrolytes. The PEO layer of the SLM implants released silver ions for at least 28 days. X-ray diffraction analysis detected hydroxyapatite on the SLM PEO implants but not on the corresponding solid implants. In vitro and ex vivo assays showed strong antimicrobial activity of these novel SLM PEO silver-releasing implants, without any signs of cytotoxicity. The rationally designed SLM porous implants outperformed solid implants with similar dimensions undergoing the same biofunctionalization treatment. This included four times larger amount of released silver ions, two times larger zone of inhibition, and one additional order of magnitude of reduction in numbers of CFU in an ex vivo mouse infection model. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Pilot study on the efficacy of combined intraoral and extraoral low-level laser therapy for prevention of oral mucositis in pediatric patients undergoing hematopoietic stem cell transplantation.

    Science.gov (United States)

    Soto, Marcos; Lalla, Rajesh V; Gouveia, Roseane Vasconcelos; Zecchin, Victor Gattardello; Seber, Adriana; Lopes, Nilza Nelly Fontana

    2015-11-01

    Studies suggest that intraoral low-level laser therapy (LLLT) can ameliorate oral mucositis in adult patients receiving high-dose chemotherapy. The objective of this study was to evaluate the use of a combined protocol of intraoral and extraoral LLLT in children undergoing hematopoietic stem cell transplantation (HSCT). Twelve children undergoing HSCT were treated four times a week with a combined protocol of intraoral and extraoral LLLT, for a mean duration of 22 days. Clinical and functional mucositis scores were assessed using the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE). These scores were compared with a matched retrospective control group of 12 children who did not receive LLLT during HSCT. Clinical mucositis scores were significantly lower in the LLLT group than in the control group (p = 0.004). Incidence of ulcerative oral mucositis was also significantly lower in the LLLT group (p = 0.027). Functional limitation associated with diet/swallowing was less severe in the LLLT group; however, this was not statistically significant. This study indicates that a combined protocol of intraoral and extraoral application of LLLT can reduce the severity of oral mucositis in pediatric patients undergoing HSCT. Randomized double-blind clinical trials with a larger number of subjects are needed to further test such combined protocols.

  17. Low-level laser therapy in the prevention and treatment of cancer therapy-induced mucositis: 2012 state of the art based on literature review and meta-analysis.

    Science.gov (United States)

    Bensadoun, René-Jean; Nair, Raj G

    2012-07-01

    To discuss the promising state of the art low-level laser therapy (LLLT) for preventive and therapeutic usage in oral mucositis due to cancer therapy. Photomedicine using LLLT is very effective with intraoral and extraoral devices in the management of oral mucositis, based on several studies including randomized control studies. A systematic review identified 33 relevant articles that were subjected to meta-analysis based on which laser parameters in routine practice are being defined. Meta-analysis showed that LLLT reduced risk of oral mucositis with relative risk (RR) 2.45 [confidence interval (CI) 1.85-3.18], reduced duration, severity of oral mucositis and reduced number of days with oral mucositis (4.38 days, P = 0.0009). RR was similar between the red (630-670 nm) and infrared (780-830 nm) LLLT. Pain-relieving effect based on the Cohen scale was at 1.22 (CI 0.19-2.25). No adverse side effects of LLLT were reported; hence, we recommend red or infrared LLLT with diode output between 10-100 mW, dose of 2-3 J/cm2/cm2 for prophylaxis and 4 J/cm2 (maximum limit) for therapeutic effect, application on single spot rather than scanning motion. Lesions must be evaluated by a trained clinician and therapy should be repeated daily or every other day or a minimum of three times per week until resolution. There is moderate-to-strong evidence in favor of LLLT at optimal doses as a well tolerated, relatively inexpensive intervention for cancer therapy-induced oral mucositis. It is envisaged that LLLT will soon become part of routine oral supportive care in cancer.

  18. Preventing stroke

    Science.gov (United States)

    Stroke - prevention; CVA - prevention; Cerebral vascular accident - prevention; TIA - prevention; Transient ischemic attack - prevention ... something that increases your chance of having a stroke. You can't change some risk factors for ...

  19. Is adjuvant laser therapy effective for preventing pain, swelling, and trismus after surgical removal of impacted mandibular third molars? A systematic review and meta-analysis.

    Science.gov (United States)

    Brignardello-Petersen, Romina; Carrasco-Labra, Alonso; Araya, Ignacio; Yanine, Nicolas; Beyene, Joseph; Shah, Prakesh S

    2012-08-01

    To assess the efficacy and safety of low-level laser energy irradiation (LLEI) for decreasing pain, swelling, and trismus after surgical removal of impacted mandibular third molars (IMTMs). MEDLINE, EMBASE, and the Central Register of Controlled Trials of the Cochrane Library were searched from their inception, and conference proceedings, cross-references, and gray literature were searched for the last 5 years for randomized and quasi-randomized controlled trials that evaluated the effects of any type of LLEI, compared with active or inactive treatments, in patients undergoing surgical removal of IMTMs. Risk of bias in included studies was assessed by 2 independent evaluators using the Cochrane Risk of Bias tool. A random-effects model meta-analysis was used to estimate the mean difference of trismus between the groups. Heterogeneity was assessed using Cochran χ(2) and I(2). Ten eligible trials were included in this systematic review. The included studies overall had a moderate risk of bias. Because of heterogeneity in the intervention and outcomes assessments, pain and swelling outcomes were only qualitatively summarized and indicated no beneficial effects of LLEI over placebo. Patients receiving LLEI had an average of 4.2 mm (95% confidence interval, 1.2 to 7.2) and 5.2 mm (95% confidence interval, 1.8 to 8.2) less trismus than patients receiving no active treatment on the second and seventh day after the surgery, respectively. There was no benefit of LLEI on pain or swelling and a moderate benefit on trismus after removal of IMTMs. It is necessary to standardize the intervention and outcomes assessment and to conduct adequately powered, well-designed trials to evaluate the efficacy of LLEI. Copyright © 2012 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  20. Lasers technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2014-07-01

    The Laser Technology Program of IPEN is developed by the Center for Lasers and Applications (CLA) and is committed to the development of new lasers based on the research of new optical materials and new resonator technologies. Laser applications and research occur within several areas such as Nuclear, Medicine, Dentistry, Industry, Environment and Advanced Research. Additional goals of the Program are human resource development and innovation, in association with Brazilian Universities and commercial partners.

  1. Laser handbook

    CERN Document Server

    Bass, Michael

    1985-01-01

    Volume 4 of the Laser Handbook continues the high standard set by the first three volumes which were widely acclaimed by numerous reviewers in Science, Optical Spectra and Laser Technology, as presenting an outstanding contribution to the field of laser technology.

  2. Microchip Lasers

    Science.gov (United States)

    2016-10-31

    USA E-mail: zayhowski@ll.mit.edu Abstract Microchip lasers are a rich family of solid-state lasers defined by their small size, robust integration...reliability, and potential for low-cost mass production. Continuous-wave microchip lasers cover a wide range of wavelengths, often operate single

  3. Lasers (Rev.)

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1969-01-01

    A laser is an instrument that produces an enormously intense pencil-thin beam of light. In this booklet we shall learn what there is about the laser that gives it so much promise. We shall investigate what it is, how it works, and the different kinds of lasers there are.

  4. Laser photocoagulation - eye

    Science.gov (United States)

    Laser coagulation; Laser eye surgery; Photocoagulation; Laser photocoagulation - diabetic eye disease; Laser photocoagulation - diabetic retinopathy; Focal photocoagulation; Scatter (or pan retinal) photocoagulation; Proliferative ...

  5. Microdentistry with Lasers

    Science.gov (United States)

    Prathima, G S; Bhadrashetty, Dinesh; Babu, S B Umesh; Disha, P

    2015-01-01

    Treating infants and young children is a rewarding experience, especially when we guide parents and children down the path of prevention and interception of oral disease. The pediatric dentist has to be updated about the new technologies to treating patients along with basic principles. This article gives a brief discussion on the types, applications, advantages, and limitations of the use of lasers in pediatric dentistry. PMID:26435633

  6. Biocavity Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Gourley, P.L.; Gourley, M.F.

    2000-10-05

    Laser technology has advanced dramatically and is an integral part of today's healthcare delivery system. Lasers are used in the laboratory analysis of human blood samples and serve as surgical tools that kill, burn or cut tissue. Recent semiconductor microtechnology has reduced the size o f a laser to the size of a biological cell or even a virus particle. By integrating these ultra small lasers with biological systems, it is possible to create micro-electrical mechanical systems that may revolutionize health care delivery.

  7. Novel preventive treatment options

    DEFF Research Database (Denmark)

    Longbottom, C; Ekstrand, K; Zero, D

    2009-01-01

    ozone therapy and probiotics; measures to increase enamel resistance to demineralization, including laser treatment of enamel, and a novel 'hybrid' technique for the treatment of primary molar caries which involves 'overlapping' of secondary and tertiary prevention--the Hall technique. Although many...... to that point. These include: approximal sealants; fluoride applications, including slow-release devices; measures to help remineralize demineralized tissue, including 3 different methods of delivering amorphous calcium phosphate; measures to help modify the biofilm to reduce the cariogenic challenge, including...

  8. High power lasers & systems

    OpenAIRE

    Chatwin, Chris; Young, Rupert; Birch, Philip

    2015-01-01

    Some laser history;\\ud Airborne Laser Testbed & Chemical Oxygen Iodine Laser (COIL);\\ud Laser modes and beam propagation;\\ud Fibre lasers and applications;\\ud US Navy Laser system – NRL 33kW fibre laser;\\ud Lockheed Martin 30kW fibre laser;\\ud Conclusions

  9. Lasers use in dental implantology.

    Science.gov (United States)

    Romanos, Georgios E; Gupta, Bhumija; Yunker, Mike; Romanos, Enisa Begic; Malmstrom, Hans

    2013-06-01

    The purpose of this literature review was to evaluate the present use of different laser systems in implant dentistry. A literature search of MEDLINE-PubMed for articles published, describing the use of lasers in implant dentistry, was performed and articles were critically reviewed by the investigators to determine the strength of evidence. The literature review reveals a limited number of randomized clinical trials with regard to laser use in dentistry. Although many case studies indicate extensive use of lasers and promising results in dental implantology, lasers may be used for uncovering submerged implants atraumatically to prevent crestal bone loss, recontouring periimplant soft tissues and sculpting emergence profile for prosthetic components, raising surgical flaps, osseous recontouring, and creating parabolic tissue architecture. Additionally, bone harvesting of block grafts, window preparation in sinus lift procedures, ridge splitting, and debridement of extraction sockets for immediate implant placement were described. Aside from the many benefits associated with the use of lasers in implant-related procedures, there are also risks to consider from the laser irradiation on the implant surface and the periimplant tissues. Therefore, an appropriate training on laser use is mandatory to increase the clinical outcome and to control the potential of complications.

  10. Remote electrical arc suppression by laser filamentation

    CERN Document Server

    Schubert, Elise; Kasparian, Jérôme; Wolf, Jean-Pierre

    2015-01-01

    We investigate the interaction of narrow plasma channels formed in the filamentation of ultrashort laser pulses, with a DC high voltage. The laser filaments prevent electrical arcs by triggering corona that neutralize the high-voltage electrodes. This phenomenon, due to the electric field modulation and free electron release around the filament, opens new prospects to lightning and over-voltage mitigation.

  11. Paediatric laser dentistry. Part 1: General introduction.

    Science.gov (United States)

    Caprioglio, C; Olivi, G; Genovese, M D

    2017-03-01

    Knowledge of the physical characteristics of different laser lights and optical and thermal properties of oral tissues is very important to understand the interaction of dental lasers with biological tissues. Choosing the correct dental laser is crucial to match specific wavelengths with target chromophores of different tissues; this affinity makes laser irradiation selective and therefore minimally invasive. Various types of lasers are used in dentistry, offering a viable alternative to low and high-speed handpieces and surgical blades, and also minimising fear and discomfort of the patient. Lasers can provide innovative and minimally invasive therapies in different branches of dentistry including preventive and restorative dentistry, traumatic injury treatments and surgical procedures. Laser has also biostimulating and anti-inflammatory effects, as well as analgesic effect.

  12. Long-term survival of a randomized phase III trial of head and neck cancer patients receiving concurrent chemoradiation therapy with or without low-level laser therapy (LLLT) to prevent oral mucositis.

    Science.gov (United States)

    Antunes, Héliton S; Herchenhorn, Daniel; Small, Isabele A; Araújo, Carlos M M; Viégas, Celia Maria Pais; de Assis Ramos, Gabriela; Dias, Fernando L; Ferreira, Carlos G

    2017-08-01

    The impact of low-level laser therapy (LLLT) to prevent oral mucositis in patients treated with exclusive chemoradiation therapy remains unknown. This study evaluated the overall, disease-free and progression-free survival of these patients. Overall, disease-free and progression-free survival of 94 patients diagnosed with oropharynx, nasopharynx, and hypopharynx cancer, who participated on a phase III study, was evaluated from 2007 to 2015. The patients were subjected to conventional radiotherapy plus cisplatin every 3weeks. LLLT was applied with an InGaAlP diode (660nm-100mW-1J-4J/cm2). With a median follow-up of 41.3months (range 0.7-101.9), patients receiving LLLT had a statistically significant better complete response to treatment than those in the placebo group (LG=89.1%; PG=67.4%; p=0.013). Patients subjected to LLLT also displayed increase in progression-free survival than those in the placebo group (61.7% vs. 40.4%; p=0.030; HR:1:93; CI 95%: 1.07-3.5) and had a tendency for better overall survival (57.4% vs. 40.4%; p=0.90; HR:1.64; CI 95%: 0.92-2.91). This is the first study to suggest that LLLT may improve survival of head and neck cancer patients treated with chemoradiotherapy. Further studies, with a larger sample, are necessary to confirm our findings. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Lasers technology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    The Lasers Technology Program of IPEN is strongly committed to the study of Laser Applications on several areas: Nuclear, Medicine and Dentistry, Industry, Environment and Advanced research, aiming not only research but diffusion and innovation in association with Brazilian universities and commercial partners.

  14. Laser device

    Science.gov (United States)

    Scott, Jill R.; Tremblay, Paul L.

    2008-08-19

    A laser device includes a virtual source configured to aim laser energy that originates from a true source. The virtual source has a vertical rotational axis during vertical motion of the virtual source and the vertical axis passes through an exit point from which the laser energy emanates independent of virtual source position. The emanating laser energy is collinear with an orientation line. The laser device includes a virtual source manipulation mechanism that positions the virtual source. The manipulation mechanism has a center of lateral pivot approximately coincident with a lateral index and a center of vertical pivot approximately coincident with a vertical index. The vertical index and lateral index intersect at an index origin. The virtual source and manipulation mechanism auto align the orientation line through the index origin during virtual source motion.

  15. Laser instrument

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera, R.J.; Eagar, T.W.

    1986-04-08

    An instrument is described for intercepting a carbon dioxide incident laser beam after it has energized a desired surgical target site but before it energizes material adjacent to the surgical target site. The instrument consists of: a substrate means for transmitting energy received from a laser beam away from a surgical target site, the substrate means having a high thermal conductivity and an exterior surface; a coating means for absorbing laser energy at the wavelength of a carbon dioxide laser, the coating means covering substantially the entirety of the exterior surface of the substrate means and having a high absorptivity for energy at the wavelength of the incident laser beam; and, the coating means having thickness which is large enough to provide high absorptivity but small enough to permit absorbed energy to be readily transferred to the high conductivity substrate means, and the thickness of the coating means being not greater than 0.001 inch.

  16. Dengue Prevention

    Science.gov (United States)

    ... Address What's this? Submit What's this? Submit Button Prevention Recommend on Facebook Tweet Share Compartir This photograph ... medications to treat a dengue infection. This makes prevention the most important step, and prevention means avoiding ...

  17. High throughput laser processing

    Energy Technology Data Exchange (ETDEWEB)

    Harley, Gabriel; Pass, Thomas; Cousins, Peter John; Viatella, John

    2016-12-27

    A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

  18. Investigation of Laser Peening Effects on Hydrogen Charged Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Zaleski, Tania M. [San Jose State Univ., CA (United States)

    2008-10-30

    Hydrogen-rich environments such as fuel cell reactors can exhibit damage caused by hydrogen permeation in the form of corrosion cracking by lowering tensile strength and decreasing material ductility. Coatings and liners have been investigated, but there were few shot-peening or laser peening studies referenced in the literature with respect to preventing hydrogen embrittlement. The surface compressive residual stress induced by laser peening had shown success in preventing stress corrosion cracking (SCC) for stainless steels in power plants. The question arose if the residual stresses induced by laser peening could delay the effects of hydrogen in a material. This study investigated the effect of laser peening on hydrogen penetration into metal alloys. Three areas were studied: laser peening, hydrogenation, and hydrogen detection. This study demonstrated that laser peening does not reduce the hydrogen permeation into a stainless steel surface nor does it prevent hydrogen embrittlement. The effect of laser peening to reduce hydrogen-assisted fatigue was unclear.

  19. Laser spectroscopy

    CERN Document Server

    Demtröder, Wolfgang

    2008-01-01

    Keeping abreast of the latest techniques and applications, this new edition of the standard reference and graduate text on laser spectroscopy has been completely revised and expanded. While the general concept is unchanged, the new edition features a broad array of new material, e.g., frequency doubling in external cavities, reliable cw-parametric oscillators, tunable narrow-band UV sources, more sensitive detection techniques, tunable femtosecond and sub-femtosecond lasers (X-ray region and the attosecond range), control of atomic and molecular excitations, frequency combs able to synchronize independent femtosecond lasers, coherent matter waves, and still more applications in chemical analysis, medical diagnostics, and engineering.

  20. Multichannel laser-fiber vibrometer

    Science.gov (United States)

    Dudzik, Grzegorz; Waz, Adam; Kaczmarek, Pawel; Antonczak, Arkadiusz; Sotor, Jaroslaw; Krzempek, Karol; Sobon, Grzegorz; Abramski, Krzysztof M.

    2013-01-01

    For the last few years we were elaborating the laser-fiber vibrometer working at 1550 nm. Our main stress was directed towards different aspects of research: analysis of scattered light, efficient photodetection, optimization of the fiber-free space interfaces and signal processing. As a consequence we proposed the idea of a multichannel fiber vibrometer based on well developed telecommunication technique - Wavelength Division Multiplexing (WDM). One of the most important parts of a fiber-laser vibrometer is demodulation electronic section. The distortion, nonlinearity, offset and added noise of measured signal come from electronic circuits and they have direct influence on finale measuring results. We present the results of finished project "Developing novel laser-fiber monitoring technologies to prevent environmental hazards from vibrating objects" where we have constructed a 4-channel WDM laser-fiber vibrometer.

  1. Laser endoscopy.

    Science.gov (United States)

    McElvein, R B

    1981-11-01

    A carbon dioxide laser operating in the invisible infrared range (10.6 mu) generates a beam of energy that is almost completely absorbed by biological tissue with release of intense heat and rapid destruction. A laser attached to a rigid bronchoscope has been used in 18 patients ranging in age from 21 to 62 years to treat a variety of causes of airway obstruction. These include tracheal stenosis and granulation tissue (6 patients), adenoma (1), web (2), and carcinoma (9). The results were good in 15 and poor in 3 patients. However, all patients had an improved airway after laser treatment with the best results occurring in patients with benign, inflammatory disease. The advantages of the laser are a lack of bleeding, minimal edema after treatment, and minimal scar formation. The disadvantages are the expense of the machine, and the need for general anesthesia and direct visualization of the lesion.

  2. Laser Refractography

    CERN Document Server

    Rinkevichyus, B.S; Raskovskaya, I.L

    2010-01-01

    This book describes the basic principles of laser refractography, a flexible new diagnostic tool for measuring optically inhomogeneous media and flows. Laser refractography is based on digital imaging and computer processing of structured laser beam refraction (SLR) in inhomogeneous transparent media. Laser refractograms provide both qualitative and quantitative measurements and can be used for the study of fast and transient processes. In this book, the theoretical basis of refractography is explored in some detail, and experimental setups are described for measurement of transparent media using either 2D (passed radiation) or 3D (scattered radiation) refractograms. Specific examples and applications are discussed, including visualization of the boundary layer near a hot or cold metallic ball in water, and observation of edge effects and microlayers in liquids and gases. As the first book to describe this new and exciting technique, this monograph has broad cross-disciplinary appeal and will be of interest t...

  3. Il laser

    CERN Document Server

    Smith, William V

    1974-01-01

    Verso il 1960, il laser era ancora "una soluzione alla ricerca di un problema", ma fin dagli anni immediatamente successivi si è rivelato uno strumento insostituibile per le applicazioni più svariate.

  4. Green lasers

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin

    2010-01-01

    Well over a dozen papers at this year's Photonics West meeting in San Francisco boasted improvements in harmonic generation to produce visible laser beams, most of them in the green spectral range......Well over a dozen papers at this year's Photonics West meeting in San Francisco boasted improvements in harmonic generation to produce visible laser beams, most of them in the green spectral range...

  5. Laser weapons

    Science.gov (United States)

    Tsipis, K.

    1981-12-01

    The potential for deploying lasers as an effective antimissile system is assessed. High intensity and precise collimation are noted as essential for lasers as weapons, although size and material properties determine the actual performance. Gas-dynamic, electron, and chemical lasers are reviewed as prime weapons candidates. Space-, ground-, and ship-based uses are considered; each demands precision pointing, involving movable mirrors, target tracking and condition sensors, and central processing for target choice, along with large capacity power generation and storage. Laser propagation in the atmosphere is degraded by absorption, scattering, thermal blooming, turbulence (causes diffraction), and plasma formation ahead of the beam. Different modes of damaging missiles are reviewed, and it is found that mirrored surfaces, ablative coatings, and fluid layers have significant abilities to protect a missile in-flight. Destroying an ICBM in the boost phase is calculated to require a one million MW generator, far beyond current power engineering capabilities. Conventional weapons are viewed as more effective than lasers, although high energy laser research may have definite applications in areas such as chemical engineering

  6. Laser therapy for cancer

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000905.htm Laser therapy for cancer To use the sharing features on ... Lasers are also used on the skin. How Laser Therapy is Used Laser therapy can be used to: ...

  7. Laser material processing

    CERN Document Server

    Steen, William

    2010-01-01

    This text moves from the basics of laser physics to detailed treatments of all major materials processing techniques for which lasers are now essential. New chapters cover laser physics, drilling, micro- and nanomanufacturing and biomedical laser processing.

  8. Selective laser melting of copper using ultrashort laser pulses

    Science.gov (United States)

    Kaden, Lisa; Matthäus, Gabor; Ullsperger, Tobias; Engelhardt, Hannes; Rettenmayr, Markus; Tünnermann, Andreas; Nolte, Stefan

    2017-09-01

    Within the field of laser-assisted additive manufacturing, the application of ultrashort pulse lasers for selective laser melting came into focus recently. In contrast to conventional lasers, these systems provide extremely high peak power at ultrashort interaction times and offer the potential to control the thermal impact at the vicinity of the processed region by tailoring the pulse repetition rate. Consequently, materials with extremely high melting points such as tungsten or special composites such as AlSi40 can be processed. In this paper, we present the selective laser melting of copper using 500 fs laser pulses at MHz repetition rates emitted at a center wavelength of about 1030 nm. To identify an appropriate processing window, a detailed parameter study was performed. We demonstrate the fabrication of bulk copper parts as well as the realization of thin-wall structures featuring thicknesses below 100 {μ }m. With respect to the extraordinary high thermal conductivity of copper which in general prevents the additive manufacturing of elements with micrometer resolution, this work demonstrates the potential for sophisticated copper products that can be applied in a wide field of applications extending from microelectronics functionality to complex cooling structures.

  9. Laser acceleration

    Science.gov (United States)

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-02-01

    The fundamental idea of Laser Wakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wakefields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ˜ c and ultrafastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nanomaterials is also emerging.

  10. Poison Prevention

    Science.gov (United States)

    ... the Word Shop AAP Find a Pediatrician Safety & Prevention Immunizations All Around At Home At Play On ... Listen Español Text Size Email Print Share Poison Prevention Page Content Article Body Post the Poison Help ...

  11. Preventing Addiction.

    Science.gov (United States)

    Moore, Susan Fordney

    The purpose of this paper is to provide the beginning counselor with an overview of prevention concepts. Prevention is a relatively new emphasis in community efforts to stem the rising costs of substance abuse and other high-risk behaviors. The paper discusses agent, host, and environmental prevention models and how they relate to causal theories…

  12. Novel preventive treatment options.

    Science.gov (United States)

    Longbottom, C; Ekstrand, K; Zero, D; Kambara, M

    2009-01-01

    A number of novel preventive treatment options which, as with traditional methods, can be differentiated into 3 categories of prevention (primary, secondary and tertiary), have been and are being currently investigated. Those reviewed are either commercially available or appear relatively close to that point. These include: approximal sealants; fluoride applications, including slow-release devices; measures to help remineralize demineralized tissue, including 3 different methods of delivering amorphous calcium phosphate; measures to help modify the biofilm to reduce the cariogenic challenge, including ozone therapy and probiotics; measures to increase enamel resistance to demineralization, including laser treatment of enamel, and a novel 'hybrid' technique for the treatment of primary molar caries which involves 'overlapping' of secondary and tertiary prevention--the Hall technique. Although many of these techniques show considerable promise and dentists should be aware of these developments and follow their progress, the evidence for each of these novel preventive treatment options is currently insufficient to make widespread recommendations. Changes in dental practice should be explored to see how oral health can be best supported through novel preventive systems. Further research is also required involving double-blind randomized controlled trials in order to bring further benefits of more effective caries control to patients. Implementation in practice should follow promptly as new techniques are shown to be clinically valuable for individual patients. Copyright 2009 S. Karger AG, Basel

  13. Laser barometer

    Science.gov (United States)

    Abercrombie, Kevin R.; Shiels, David; Rash, Tim

    2001-02-06

    A pressure measuring instrument that utilizes the change of the refractive index of a gas as a function of pressure and the coherent nature of a laser light to determine the barometric pressure within an environment. As the gas pressure in a closed environment varies, the index of refraction of the gas changes. The amount of change is a function of the gas pressure. By illuminating the gas with a laser light source, causing the wavelength of the light to change, pressure can be quantified by measuring the shift in fringes (alternating light and dark bands produced when coherent light is mixed) in an interferometer.

  14. Laser Heterodyning

    CERN Document Server

    Protopopov, Vladimir V

    2009-01-01

    Laser heterodyning is now a widespread optical technique, based on interference of two waves with slightly different frequencies within the sensitive area of a photo-detector. Its unique feature – preserving phase information about optical wave in the electrical signal of the photo-detector – finds numerous applications in various domains of applied optics and optoelectronics: in spectroscopy, polarimetry, radiometry, laser radars and Lidars, microscopy and other areas. The reader may be surprised by a variety of disciplines that this book covers and satisfied by detailed explanation of the phenomena. Very well illustrated, this book will be helpful for researches, postgraduates and students, working in applied optics.

  15. Laser yellowing

    Indian Academy of Sciences (India)

    References. [1] P Maravelaki-Kalaitzaki et al, Appl. Surf. Sci. 148, 92 (1999). [2] Th Skoulikidis et al, LACONA, Workshop on Lasers in Conservation of Artworks,. (1995). [3] Veronique Verges-Belmin et al, J. Cultural Heritage 4, 238s (2003). [4] V Zafiropulos et al, LACONA V Springer Proceedings in Physics 100, 313 (2003).

  16. Mirrorless lasers

    Indian Academy of Sciences (India)

    Abstract. Experimental realization of mirrorless lasers in the last decade have resulted in hectic activity in this field, due to their novelty, simplicity and ruggedness and their great potential for application. In this article, I will review the various developments in this field in roughly chronological order, and discuss some possible ...

  17. Dye lasers

    Energy Technology Data Exchange (ETDEWEB)

    Kuder, J.E.; McGinnis, J.L.; Goldberg, H.A.; Hart, T.R.; Che, T.M.

    1989-10-31

    This patent describes a dye laser. It consists of a composite composition of an inorganic oxide glass monolith with a microporous structure containing an incorporated solution comprising a solvent component and a lasable dye component. Wherein the glass monolith has sealed outer surfaces.

  18. Laser Dyes

    Indian Academy of Sciences (India)

    tions to be treated with laser radiation. They are congenital malformations consisting of superficial and deep dilated capillar- ies in the skin. The swollen blood vessels cause a reddish discol- oration of the skin. Although PWS can appear in any part of the body, they occur more often on the face and persist throughout life. N.

  19. Laser Dyes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 9. Laser Dyes. G S Shankarling K J Jarag. General Article Volume 15 Issue 9 September ... Author Affiliations. G S Shankarling1 K J Jarag1. Dyestuff Technology, Department Institute of Chemical Technology, Matunga Mumbai 400 019, India.

  20. Laser device

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention provides a light source for light circuits on a silicon platform. A vertical laser cavity is formed by a gain region arranged between a first mirror structure and a second mirror structure, both acting as mirrors, by forming a grating region including an active material in a...

  1. Laser yellowing

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... Author Affiliations. M B Sai Prasad1 Salvatore Siano2. Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai 400 085, India; CNR-IFAC, Polo Scientifico di Sesto Fiorentino, Via Madonna del Piano, 10, Sesto Fiorentino (FI)-50019, Italy ...

  2. excimer laser

    Indian Academy of Sciences (India)

    2014-01-07

    Jan 7, 2014 ... Excimer laser; krypton chloride; UV pre-ionization; gas circulation. PACS No 42.55.Lt. 1. ... active discharge volume is by spark UV radiation created adjacent to both sides of the. Figure 4. Output ... HV electrode, all along its length and spatially modulated to ensure uniform irradiation of the gas volume.

  3. Laser physics and a review of laser applications in dentistry for children.

    Science.gov (United States)

    Martens, L C

    2011-04-01

    The aim of this introduction to this special laser issue is to describe some basic laser physics and to delineate the potential of laser-assisted dentistry in children. A brief review of the available laser literature was performed within the scope of paediatric dentistry. Attention was paid to soft tissue surgery, caries prevention and diagnosis, cavity preparation, comfort of the patient, effect on bacteria, long term pulpal vitality, endodontics in primary teeth, dental traumatology and low level laser therapy. Although there is a lack of sufficient evidence taking into account the highest standards for evidence-based dentistry, it is clear that laser application in a number of different aetiologies for soft tissue surgery in children has proven to be successful. Lasers provide a refined diagnosis of caries combined with the appropriate preventive adhesive dentistry after cavity preparation. This will further lead to a new wave of micro-dentistry based on 'filling without drilling'. It has become clear from a review of the literature that specific laser applications in paediatric dentistry have gained increasing importance. It can be concluded that children should be considered as amongst the first patients for receiving laser-assisted dentistry.

  4. Nanowire Lasers

    Directory of Open Access Journals (Sweden)

    Couteau C.

    2015-05-01

    Full Text Available We review principles and trends in the use of semiconductor nanowires as gain media for stimulated emission and lasing. Semiconductor nanowires have recently been widely studied for use in integrated optoelectronic devices, such as light-emitting diodes (LEDs, solar cells, and transistors. Intensive research has also been conducted in the use of nanowires for subwavelength laser systems that take advantage of their quasione- dimensional (1D nature, flexibility in material choice and combination, and intrinsic optoelectronic properties. First, we provide an overview on using quasi-1D nanowire systems to realize subwavelength lasers with efficient, directional, and low-threshold emission. We then describe the state of the art for nanowire lasers in terms of materials, geometry, andwavelength tunability.Next,we present the basics of lasing in semiconductor nanowires, define the key parameters for stimulated emission, and introduce the properties of nanowires. We then review advanced nanowire laser designs from the literature. Finally, we present interesting perspectives for low-threshold nanoscale light sources and optical interconnects. We intend to illustrate the potential of nanolasers inmany applications, such as nanophotonic devices that integrate electronics and photonics for next-generation optoelectronic devices. For instance, these building blocks for nanoscale photonics can be used for data storage and biomedical applications when coupled to on-chip characterization tools. These nanoscale monochromatic laser light sources promise breakthroughs in nanophotonics, as they can operate at room temperature, can potentially be electrically driven, and can yield a better understanding of intrinsic nanomaterial properties and surface-state effects in lowdimensional semiconductor systems.

  5. Excimer Laser Technology

    CERN Document Server

    Basting, Dirk

    2005-01-01

    This comprehensive survey on Excimer Lasers investigates the current range of the technology, applications and devices of this commonly used laser source, as well as the future of new technologies, such as F2 laser technology. Additional chapters on optics, devices and laser systems complete this compact handbook. A must read for laser technology students, process application researchers, engineers or anyone interested in excimer laser technology. An effective and understandable introduction to the current and future status of excimer laser technology.

  6. Laser Physics and Laser Spectroscopy.

    Science.gov (United States)

    1983-06-01

    Introduction A basic idea for achieving short wavelength lasers is to work with multiply-ionized atoms. Such ions generally have larger energy differences... generacion , characterization and applications over the next graduate student generation. - 71- *1* . . . . . . - o - - ° ... VII. PUBLICATIONS AND

  7. Prevention: Exercise

    Medline Plus

    Full Text Available ... Therapy Postural Training Traction Watchful Waiting and Education Injection Treatments for Spinal Pain Epidural Steroid Injections Lumbar Zygapophysical (Facet) Joint Injections PREVENTION Lifestyle Choices ...

  8. Prevention: Exercise

    Medline Plus

    Full Text Available ... Steroid Injections Lumbar Zygapophysical (Facet) Joint Injections PREVENTION Lifestyle Choices 10 Tips for a Healthy Back Smoking Weight Patient Safety Exercise Strengthening Strengthen ...

  9. Application of Laser Irradiation for Restorative Treatments

    Science.gov (United States)

    Davoudi, Amin; Sanei, Maryam; Badrian, Hamid

    2016-01-01

    Nowadays, lasers are widely used in many fields of medicine. Also, they can be applied at many branches of dental practice such as diagnosis, preventive procedures, restorative treatments, and endodontic therapies. Procedures like caries removal, re-mineralization, and vital pulp therapy are the most noticeable effects of laser irradiation which has gained much attention among clinicians. With controlled and appropriate wavelength, they can help stimulating dentinogenesis, controlling pulpal hemorrhage, sterilization, healing of collagenic proteins, formation of a fibrous matrix, and inducing hard tissue barrier. Nevertheless, there are many controversies in literatures regarding their effects on the quality of bonded restorations. It hampered a wide application of lasers in some aspects of restorative dentistry and requirements to identify the best way to use this technology. The aim of this mini review is to explain special characteristics of laser therapy and to introduce the possible applications of laser devices for dental purposes. PMID:27990188

  10. Application of Laser Irradiation for Restorative Treatments.

    Science.gov (United States)

    Davoudi, Amin; Sanei, Maryam; Badrian, Hamid

    2016-01-01

    Nowadays, lasers are widely used in many fields of medicine. Also, they can be applied at many branches of dental practice such as diagnosis, preventive procedures, restorative treatments, and endodontic therapies. Procedures like caries removal, re-mineralization, and vital pulp therapy are the most noticeable effects of laser irradiation which has gained much attention among clinicians. With controlled and appropriate wavelength, they can help stimulating dentinogenesis, controlling pulpal hemorrhage, sterilization, healing of collagenic proteins, formation of a fibrous matrix, and inducing hard tissue barrier. Nevertheless, there are many controversies in literatures regarding their effects on the quality of bonded restorations. It hampered a wide application of lasers in some aspects of restorative dentistry and requirements to identify the best way to use this technology. The aim of this mini review is to explain special characteristics of laser therapy and to introduce the possible applications of laser devices for dental purposes.

  11. Free-space QKD system hacking by wavelength control using an external laser.

    Science.gov (United States)

    Lee, Min Soo; Woo, Min Ki; Jung, Jisung; Kim, Yong-Su; Han, Sang-Wook; Moon, Sung

    2017-05-15

    We develop a way to hack free-space quantum key distribution (QKD) systems by changing the wavelength of the quantum signal laser using an external laser. Most free-space QKD systems use four distinct lasers for each polarization, thereby making the characteristics of each laser indistinguishable. We also discover a side-channel that can distinguish the lasers by using an external laser. Our hacking scheme identifies the lasers by automatically applying the external laser to each signal laser at different intensities and detecting the wavelength variation according to the amount of incident external laser power. We conduct a proof-of-principle experiment to verify the proposed hacking structure and confirm that the wavelength varies by several gigahertzes to several nanometers, depending on the intensity of the external laser. The risk of hacking is successfully proven through the experimental results. Methods for prevention are also suggested.

  12. RILIS laser room HD

    CERN Multimedia

    2016-01-01

    Footage of the RILIS laser room at ISOLDE. The Resonance Ionization Laser Ion Source (RILIS) is a chemically selective ion source which relies on resonant excitation of atomic transitions using tunable laser radiation. This video shows you the laser table with the different lenses and optics as well as an overview of the RILIS laser setup. It also shows laser light with different colors and operation by the RILIS laser experts. The last part of the video shows you the laser path from the RILIS laser room into the ISOLDE GPS separator room where it enters the GPS separator magnet.

  13. RILIS laser room

    CERN Multimedia

    2016-01-01

    Footage of the RILIS laser room at ISOLDE. The Resonance Ionization Laser Ion Source (RILIS) is a chemically selective ion source which relies on resonant excitation of atomic transitions using tunable laser radiation. This video shows you the laser table with the different lenses and optics as well as an overview of the RILIS laser setup. It also shows laser light with different colors and operation by the RILIS laser experts. The last part of the video shows you the laser path from the RILIS laser room into the ISOLDE GPS separator room where it enters the GPS separator magnet.

  14. Lasers and medicine

    Energy Technology Data Exchange (ETDEWEB)

    Deren, Przemyslaw J. [Institute of Low Temperatures and Structure Researches, Polish Academy of Sciences, P.O.Box 1410, 50-950 Wroclaw (Poland)

    2004-02-01

    This paper presents physical bases of laser light interaction with biological tissue. Invasive and non-invasive laser applications like laser knife (scalpel), biostymulation - Low Level Laser Therapy, laser diagnosis and therapy especially Photodynamic Diagnosis and Therapy are reviewed. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Preventative Maintenance.

    Science.gov (United States)

    Migliorino, James

    Boards of education must be convinced that spending money up front for preventive maintenance will, in the long run, save districts' tax dollars. A good program of preventive maintenance can minimize disruption of service; reduce repair costs, energy consumption, and overtime; improve labor productivity and system equipment reliability; handle…

  16. The diabetic foot and leg: combined He-Ne and infrared low-intensity lasers improve skin blood perfusion and prevent potential complications. A prospective study on 30 Egyptian patients.

    Science.gov (United States)

    Saied, Gamal M; Kamel, Ragia M; Labib, Awatif M; Said, Mohamed T; Mohamed, Abir Z

    2011-09-01

    The objective of this study was to examine skin blood flow in diabetic patients having disease-related skin lesions, and to evaluate possible improvement imposed by low-intensity laser therapy (LILT) as a new treatment modality. Thirty patients (in addition to 15 controls receiving conventional treatment = group II and 15 others receiving no treatment = group III) having diabetes-related skin lesions were tested for skin blood flow by laser Doppler flowmetry. Group I patients received LILT by a specified dosimetry. This was by combined uniform He-Ne and infrared lasers delivered by a scanner over the affected area. This study used a paired t test to determine the significance of blood flow recovery after treatment within each group while Independent t test compared results between the three groups. The level of significance was p < 0.05. The most frequently detected diabetes specific skin lesions were dryness, nail changes, hair loss, infections, itching, and frank eczema-like reactions, mostly in combinations (76%). This pattern appears specific for Egyptians as it is different from data registered in foreign literature. The minimum perfusion flow improved from 16.45 before LILT to 25.94 after, while maximum flow recovered from 32.91 to 48.47 and basal perfusion changed from 24.68 to 34.84 blood perfusion units. The percentage change in perfusion values was 23.17. All these were statistically significant. The study demonstrates that diabetes-linked skin lesions have a special pattern in Egyptians and are apparently caused by deranged skin blood flow .The deficit is measurable by laser flowmetry and can be partially reversed by LILT.

  17. Carbon in Fly Ash Analysis Using Photoacoustic Spectroscopy.

    Science.gov (United States)

    Dykstra, Jeffrey Raymond

    Photoacoustic absorption spectroscopy (PAS) was investigated as a method for on-line monitoring of carbon in fly ash from coal-fired boilers. PAS is based on the periodic heating of a gas when amplitude-modulated radiation is absorbed by the gas or by particles suspended in the gas. This periodic heating produces an acoustical wave that can be detected by a microphone. Because the PAS signal is based solely on the absorption of radiation (by carbon) and not scattering of radiation (by mineral matter), it has the potential for distinguishing unburned carbon from mineral matter suspended in the flue gas. Two radiation sources were studied: helium-neon laser and microwaves. The helium-neon source produces a large mass specific absorption coefficient for the carbon in the fly ash. Although the optical PAS system uses less than one forty thousandths of the power as the microwave system, it still has twice the sensitivity (D etam) and the microwave source (lambda = 12.24 cm). It may be possible to find a source that has all the positive characteristics with manageable drawbacks.

  18. Advanced laser sensors

    OpenAIRE

    Ebert, R.

    2010-01-01

    The paper presents the status of laser sensors based on direct and coherent detection technology. Potential and limitations of 3D- laser radar, laser vibrometer, and gated viewing systems will be described.

  19. Laser therapy (image)

    Science.gov (United States)

    A laser is used for many medical purposes. Because the laser beam is so small and precise, it enables ... without injuring surrounding tissue. Some uses of the laser are retinal surgery, excision of lesions, and cauterization ...

  20. Laser Research Lab

    Data.gov (United States)

    Federal Laboratory Consortium — The Laser Research lab is thecenter for the development of new laser sources, nonlinear optical materials, frequency conversion processes and laser-based sensors for...

  1. Laser Protection TIL

    Data.gov (United States)

    Federal Laboratory Consortium — The Laser Protection TIL conducts research and analysis of laser protection materials along with integration schemes. The lab's objectives are to limit energy coming...

  2. Laser satellite power systems

    Energy Technology Data Exchange (ETDEWEB)

    Walbridge, E.W.

    1980-01-01

    A laser satellite power system (SPS) converts solar power captured by earth-orbiting satellites into electrical power on the earth's surface, the satellite-to-ground transmission of power being effected by laser beam. The laser SPS may be an alternative to the microwave SPS. Microwaves easily penetrate clouds while laser radiation does not. Although there is this major disadvantage to a laser SPS, that system has four important advantages over the microwave alternative: (1) land requirements are much less, (2) radiation levels are low outside the laser ground stations, (3) laser beam sidelobes are not expected to interfere with electromagnetic systems, and (4) the laser system lends itself to small-scale demonstration. After describing lasers and how they work, the report discusses the five lasers that are candidates for application in a laser SPS: electric discharge lasers, direct and indirect solar pumped lasers, free electron lasers, and closed-cycle chemical lasers. The Lockheed laser SPS is examined in some detail. To determine whether a laser SPS will be worthy of future deployment, its capabilities need to be better understood and its attractiveness relative to other electric power options better assessed. First priority should be given to potential program stoppers, e.g., beam attenuation by clouds. If investigation shows these potential program stoppers to be resolvable, further research should investigate lasers that are particularly promising for SPS application.

  3. Semiconductor Laser Measurements Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Semiconductor Laser Measurements Laboratory is equipped to investigate and characterize the lasing properties of semiconductor diode lasers. Lasing features such...

  4. Laser treatment of hypertrophic scar/span>s

    Science.gov (United States)

    Dobrjakova, Olga B.; Gulev, Valerii S.

    2001-10-01

    For prophylaxis and treatment, the pulsed solid state neodymium yttrium-aluminum garnet laser was used. It has been shown that this kind of radiation inhibits the proliferative process and prevents the scar hyperfibrotization. In this paper author's reports about the development of the method for improving the scar quality using Nd:YAG laser are presented.

  5. Prevention: Exercise

    Medline Plus

    Full Text Available ... Physical Therapy Postural Training Traction Watchful Waiting and Education Injection Treatments for Spinal Pain Epidural Steroid Injections Lumbar Zygapophysical (Facet) Joint Injections PREVENTION Lifestyle Choices 10 Tips for a Healthy Back ...

  6. Prevention: Exercise

    Medline Plus

    Full Text Available ... Exercise Strength Training for the Elderly Other Back Pack Safety Pregnancy and Back Pain Preventing Osteoporosis Back ... in very slightly. Hold a ball directly in front of you. Keep your abdominal muscles tight and ...

  7. Prevention: Exercise

    Medline Plus

    Full Text Available ... A SPECIALIST Prevention Strengthening Exercise Committee Exercise Committee Core Strengthening Many popular forms of exercise focus on ... acute pain, you should stop doing it. Transverse Core Strengthening This strengthens the muscles that cross from ...

  8. Preventive analgesia

    DEFF Research Database (Denmark)

    Dahl, Jørgen B; Kehlet, Henrik

    2011-01-01

    This paper will discuss the concepts of pre-emptive and preventive analgesia in acute and persistent postsurgical pain, based on the most recent experimental and clinical literature, with a special focus on injury-induced central sensitization and the development from acute to chronic pain. Recent...... findings: The nature of central sensitization during acute and chronic postsurgical pain share common features, and there may be interactions between acute and persistent postoperative pain. The term ‘pre-emptive analgesia’ should be abandoned and replaced by the term ‘preventive analgesia’. Recent studies...... of preventive analgesia for persistent postoperative pain are promising. However, clinicians must be aware of the demands for improved design of their clinical studies in order to get more conclusive answers regarding the different avenues for intervention. Summary: The concept of preventive analgesia is still...

  9. Prevention: Exercise

    Medline Plus

    Full Text Available ... 10 Tips for a Healthy Back Smoking Weight Patient Safety Exercise Strengthening Strengthen Your Core! Stretching/Flexibility ... Pain Preventing Osteoporosis Back Pain Basics Book RESOURCES Patient Information Feature Articles Patient Q&A Success Stories ...

  10. Prevention: Exercise

    Medline Plus

    Full Text Available ... Tips for a Healthy Back Smoking Weight Patient Safety Exercise Strengthening Strengthen Your Core! Stretching/Flexibility Aerobic ... Strength Training for the Elderly Other Back Pack Safety Pregnancy and Back Pain Preventing Osteoporosis Back Pain ...

  11. Prevention: Exercise

    Medline Plus

    Full Text Available ... Changes Hydrotherapy Manual Therapy Physical Therapy Postural Training Traction Watchful Waiting and Education Injection Treatments for Spinal Pain Epidural Steroid Injections Lumbar Zygapophysical (Facet) Joint Injections PREVENTION Lifestyle Choices 10 ...

  12. Prevention: Exercise

    Medline Plus

    Full Text Available ... and Education Injection Treatments for Spinal Pain Epidural Steroid Injections Lumbar Zygapophysical (Facet) Joint Injections PREVENTION Lifestyle ... Z Spine Specialists Videos 9 for Spine Epidural Steroid Injections Exercise: The Backbone of Spine Treatment Spondylolisthesis ...

  13. Prevention: Exercise

    Medline Plus

    Full Text Available ... Low Back Pain Chronic Low Back Pain SI Joint Pain Other Scoliosis Back Pain and Emotional Distress ... Spinal Pain Epidural Steroid Injections Lumbar Zygapophysical (Facet) Joint Injections PREVENTION Lifestyle Choices 10 Tips for a ...

  14. Prevention: Exercise

    Medline Plus

    Full Text Available ... Strengthen Your Core! Stretching/Flexibility Aerobic Exercise Cervical Exercise Strength Training for the Elderly Other Back Pack Safety Pregnancy and Back Pain Preventing Osteoporosis Back Pain Basics ...

  15. Salmonella Prevention

    Science.gov (United States)

    ... indirect contact between reptiles (turtles, iguanas, other lizards, snakes) and infants or immunocompromised persons. Don't work ... help prevent salmonellosis caused by contaminated foods. Better education of food industry workers in basic food safety ...

  16. [Laser physics].

    Science.gov (United States)

    Banús Gassol, J M

    2008-11-01

    The commission of this article plunged me into doubt. First I should confess that I don't find excuse to escape this part if somebody wants to minimally deepen in the knowledge of the biological effects of this energy source. Secondly, when we talk about results, we use terms made and defined by Physics. Often we have polemics about results, and what really happens is that we don't reach agreements because we refer to different terms to explain the same observation; in conclusion we cannot understand each other because we do not know the adequate terms; for example, hypoxemia as oxygen deficit, which is true in an anemic patient as well as in a low oxygen saturation rate. In consequence, a good review of these concepts seems necessary to me. The third reason is the confusion that exists in our environment, I think sometimes of interest, about properties and effects of different types of laser. Only a minimal knowledge of physics will help us to state the scientific basis for understanding. The problems, nevertheless, accumulate due to the fact that the universe to which this article is directed is formed by urologists. What Physics education should we suppose they have? Superficial? Medium? Is it a collective with a uniform knowledge, being it whatever it is? The implication is clear. The article depth will depend on the answers to these questions. Nevertheless, the aim of the authors is to give a base enough to know what the laser is and how it acts. For that, the answer I gave to my questions is that the reader should understand the article and have enough base for, at least, reading critically the articles about laser published in urological journals.

  17. HIV Prevention

    Centers for Disease Control (CDC) Podcasts

    2012-02-01

    Dr. Kevin Fenton, Director of CDC’s National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, talks about steps people can take to protect their health from HIV.  Created: 2/1/2012 by National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP).   Date Released: 2/1/2012.

  18. A non-destructive non-contact method of the sea-bottom structure investigation

    Directory of Open Access Journals (Sweden)

    V.A. Chupin

    2017-06-01

    Full Text Available The paper describes a nondestructive noncontact method for investigating the sea-bottom structure using hydroacoustic and laser radiation. A practical implementation of this method is also presented. The research complex incorporates a state-of-the-art low-frequency hydroacoustic radiating system and a system of coastal laser strainmeters arranged in the specially selected sea waters and coastal grounds. The hydroacoustic radiators are used to generate a seismic signal. Seismic superficial waves are recorded by the coastal laser strainmeters. Optical parts of the strainmeters are constructed as the unequal-path Michelson interferometer where the frequency-stable helium-neon lasers serve as emission sources. A preliminary model of the sea-bottom testing ground has been developed by application of geologic-geophysical procedures. The model-based analysis of the timing data of the recorded seismic waves was carried out. The prospectivity of the used method was proved.

  19. Investigation of stress induced by CO2 laser processing of fused silica optics for laser damage growth mitigation.

    Science.gov (United States)

    Gallais, Laurent; Cormont, Philippe; Rullier, Jean-Luc

    2009-12-21

    Laser damage mitigation' is a process developed to prevent the growth of nanosecond laser-initiated damage sites under successive irradiation. It consists of re-fusing the damage area with a CO2 laser. In this paper we investigate the stress field created around mitigated sites which could have an influence on the efficiency of the process. A numerical model of CO2 laser interaction with fused silica is developed. It takes into account laser energy absorption, heat transfer, thermally induced stress and birefringence. Residual stress near mitigated sites in fused silica samples is characterized with specific photoelastic methods and theoretical data are compared to experiments. The stress distribution and quantitative values of stress levels are obtained for sites treated with the CO2 laser in various conditions of energy deposition (beam size, pulse duration, incident power). The results provided evidence that the presence of birefringence/residual stress around the mitigated sites has an effect on their laser damage resistance.

  20. Prophylactic laser treatment hastens choroidal neovascularization in unilateral age-related maculopathy: final results of the drusen laser study.

    Science.gov (United States)

    Owens, Sarah L; Bunce, Catey; Brannon, Alan J; Xing, Wen; Chisholm, Iain H; Gross, Mirjam; Guymer, Robyn H; Holz, Frank G; Bird, Alan C

    2006-02-01

    The Drusen Laser Study evaluated macular laser to prevent choroidal neovascularization (CNV) and vision loss in high-risk age-related maculopathy (ARM). Prospective, interventional, randomized, controlled clinical trial in five hospital centers. Patients in the unilateral group had neovascular ARM and drusen in the study eye. Study eyes were randomized to laser-treated or no-laser groups. For patients in the bilateral drusen group, eyes were randomized to right eye, laser or no laser; and left eye, alternative. Laser treatment comprised 12 argon spots. Outcome was best-corrected visual acuity and CNV signs, which were monitored for 3 years. In the unilateral group, vision loss occurred in 21 (28.8%) of 73 patients in laser vs 13 (19.7%) of 66 no-laser patients (P=.214). Incidence of CNV was 27 (29.7%) of 91 in laser vs 15 (17.65%) of 85 no-laser patients (P=.061). CNV onset was approximately 6 months earlier in laser-treated compared with no-laser patients (P=.05). In the bilateral group, vision loss occurred in six (8.3%) of 72 laser-treated vs 10 (13.9%) of 72 fellow eyes (P=.3877). CNV incidence was 12 (11.6%) of 103 in laser-treated vs seven (6.8%) of 103 fellow eyes (P=.225). There was no difference in onset of CNV. Results do not support prophylactic laser of the fellow eye of patients with neovascular ARM. Its role in patients with bilateral drusen remains unclear.

  1. Visible Solid State Lasers

    NARCIS (Netherlands)

    Hikmet, R.A.M.

    2007-01-01

    Diode lasers can be found in various applications most notably in optical communication and optical storage. Visible lasers were until recently were all based on IR diode lasers. Using GaN, directly blue and violet emitting lasers have also been introduced to the market mainly in the area of optical

  2. Lasers in cosmetic dentistry.

    Science.gov (United States)

    Pang, Peter

    2008-01-01

    Lasers have become a necessary instrument in the esthetic restorative armamentarium. This article presents smile design guidelines for soft tissue lasers, as well as an overview of hard tissue procedures that may be performed using all-tissue lasers. The goal is to help dentists determine the appropriate laser for a given clinical situations.

  3. Laser Wire Stripper

    Science.gov (United States)

    1983-01-01

    NASA-developed space shuttle technology is used in a laser wire stripper designed by Raytheon Company. Laser beams cut through insulation on a wire without damaging conductive metal, because laser radiation that melts plastic insulation is reflected by the metal. The laser process is fast, clean, precise and repeatable. It eliminates quality control problems and the expense of rejected wiring.

  4. High Power Vanadate lasers

    CSIR Research Space (South Africa)

    Strauss, HJ

    2006-07-01

    Full Text Available This presentation aims at the following: to develop new techniques to mount laser crystals; compare the laser properties of two equally doped, high power Nd:YVO4 and Nd: GdVO4 lasers; build a 1um vanadate laser with average output power exceeding...

  5. A laser radar experiment

    Science.gov (United States)

    Stiglitz, Martin R.; Blanchard, Christine

    1990-09-01

    An experiment demonstrating the feasibility of using a laser radar for long-range target acquisition and tracking is discussed. A CO2 laser was used to collect range Doppler images, while a medium-power argon ion laser was employed for angular tracking. Laser-radar operation is outlined with emphasis on isotopic laser radars. Laser-radar imaging is covered, and a laser-radar range equation is given. Experimental laser-radar transmitter, receiver, and telescope are described. A 35-foot long surface-to-air missile and payload were tracked in the experiment, with the laser radar acquiring the targets as they reached 480 km in altitude, 750 km from the radar site. The 4-ft-diameter aperture laser-radar telescope provided the resolution and range accuracy equivalent to that of a 120-ft microwave radar antenna.

  6. Multibeam fiber laser cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Hansen, Klaus Schütt; Nielsen, Jakob Skov

    2009-01-01

    The appearance of the high power high brilliance fiber laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating Cutting laser, the CO2 laser. However, quality problems in fiber......-laser cutting have until now limited its application to metal cutting. In this paper the first results of proof-of-principle Studies applying a new approach (patent pending) for laser cutting with high brightness and short wavelength lasers will be presented. In the approach, multibeam patterns are applied...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from two single mode fiber lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W...

  7. Multibeam Fibre Laser Cutting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove

    The appearance of the high power high brilliance fibre laser has opened for new possibilities in laser materials processing. In laser cutting this laser has demonstrated high cutting performance compared to the dominating cutting laser, the CO2-laser. However, quality problems in fibre......-laser cutting have until now limited its application in metal cutting. In this paper the first results of proof-of-principle studies applying a new approach (patent pending) for laser cutting with high brightness short wavelength lasers will be presented. In the approach, multi beam patterns are applied...... to control the melt flow out of the cut kerf resulting in improved cut quality in metal cutting. The beam patterns in this study are created by splitting up beams from 2 single mode fibre lasers and combining these beams into a pattern in the cut kerf. The results are obtained with a total of 550 W of single...

  8. Retained laser fibre: insights and management.

    Science.gov (United States)

    Lekich, C; Hannah, P

    2014-06-01

    To describe a case of retained endovenous laser fibre. To review the literature and Food and Drug Administration device failure reports. To suggest protocols for avoiding this complication and a method of removal. A case of retained fibre removal is described. Fibre removal techniques in vivo and ex vivo in a bovine model on the laboratory bench are presented. Successful in vivo and ex vivo fibre removal was performed using duplex ultrasound scan guided phlebectomy techniques. Unexplained measured fibre-length discrepancies due to misleading manufacturer's packaging was discovered. Simple ultrasound-guided micro-phlebectomy techniques can be used to remove retained laser fibres in the office environment. Laser fibre length measurements before and after treatment are recommended. Some preventive guidelines are described to avoid, or at least diagnose immediately, this complication, such as the 'Laser Eclipse Sign'. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  9. Computing Temperatures In Optically Pumped Laser Rods

    Science.gov (United States)

    Farrukh, Usamah O.

    1991-01-01

    Computer program presents new model solving temperature-distribution problem for laser rods of finite length and calculates both radial and axial components of temperature distributions in these rods. Contains several self-checking schemes to prevent over-writing of memory blocks and to provide simple tracing of information in case of trouble. Written in Microsoft FORTRAN 77.

  10. The laser in urology

    Science.gov (United States)

    Hofstetter, Alfons G.

    2002-10-01

    Laser is an acronym for a physical principle and means: Light Amplification by stimulated Emission of Radiation. This principle offers a lot of tissue/light effects caused by the parameters: power density/time and the special qualities of the laser light. Nowadays for diagnosis and therapy following lasers are used in urology: Krypton- and Dye-lasers as well as the Neodymium-YAG- (nd:YAG-), Holmium-YAG (Ho:YAG-), Diode-, Argon- and the CO2-lasers.

  11. Prevent Pneumonia

    Centers for Disease Control (CDC) Podcasts

    2015-08-06

    CDC’s Matthew Westercamp explains what pneumonia is, its symptoms, and how to prevent it.  Created: 8/6/2015 by National Center for Immunization and Respiratory Diseases (NCIRD), Division of Bacterial Diseases (DBD), Respiratory Diseases Branch (RDB).   Date Released: 8/6/2015.

  12. Bullying Prevention

    Science.gov (United States)

    Kemp, Patrice

    2016-01-01

    The focus of the milestone project is to focus on bridging the gap of bullying and classroom instruction methods. There has to be a defined expectations and level of accountability that has to be defined when supporting and implementing a plan linked to bullying prevention. All individuals involved in the student's learning have to be aware of…

  13. HIV Prevention

    Science.gov (United States)

    ... Abroad Treatment Basic Statistics Get Tested Find an HIV testing site near you. Enter ZIP code or city Follow HIV/AIDS CDC HIV CDC HIV/AIDS See RSS | ... Collapse All Is abstinence the only 100% effective HIV prevention option? Yes. Abstinence means not having oral, ...

  14. Laser ablation principles and applications

    CERN Document Server

    1994-01-01

    Laser Ablation provides a broad picture of the current understanding of laser ablation and its many applications, from the views of key contributors to the field. Discussed are in detail the electronic processes in laser ablation of semiconductors and insulators, the post-ionization of laser-desorbed biomolecules, Fourier-transform mass spectroscopy, the interaction of laser radiation with organic polymers, laser ablation and optical surface damage, laser desorption/ablation with laser detection, and laser ablation of superconducting thin films.

  15. Experimental and theoretical studies of picosecond laser interactions with electronic materials-laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Mao, Samuel S. [Univ. of California, Berkeley, CA (United States)

    2000-05-01

    Lasers having picosecond and shorter pulse duration are receiving much attention due to their capabilities for direct-write micromachining on many materials with minimal substrate damage. Substantial progress has been made in the understanding of laser ablation processes, particularly the creation of plasmas that often shield the target and reduce the material processing efficiency at nanosecond time scales. However, a considerable challenge that still remains is the understanding of the underlying mechanisms during picosecond laser interactions with electronic solids. In this work we first study picosecond laser-induced electron emission from semiconductor surfaces. A theoretical model was set up based on carrier transport inside the semiconductor material during picosecond laser-semiconductor interactions. We demonstrate that nonequilibrium carrier dynamics plays a significant role for picosecond, as well as short nanosecond, laser induced electron emission from semiconductors. Photoelectric effect is found to be responsible for electron emission at low incident laser fluences, whereas thermionic emission is dominant at higher fluences. We have also performed experimental and theoretical studies on the formation and subsequent evolution of plasmas during laser-metal interactions at the picosecond time scale. Using picosecond time-resolved shadowgrams ahd interferograms, a novel type of plasma is observed, which has an electron density on the order of 1020cm-3.The origin of this picosecond plasma is attributed to gas breakdown, which is caused by laser-induced electron emission fi-om the target surface. After the laser pulse is completed, the longitudinal expansion of the plasma is suppressed. This suppression is found to result from an electric field above the target that prevents, after laser irradiation, fbrther movement of the electrons inside the plasma. Measurements of lateral plasma expansion indicate that the picosecond plasma may absorb

  16. Ceramic Laser Materials

    Directory of Open Access Journals (Sweden)

    Guillermo Villalobos

    2012-02-01

    Full Text Available Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers, ultrashort pulse lasers, novel materials such as sesquioxides, fluoride ceramic lasers, selenide ceramic lasers in the 2 to 3 μm region, composite ceramic lasers for better thermal management, and single crystal lasers derived from polycrystalline ceramics. This paper highlights some of these notable achievements.

  17. Raman fiber lasers

    CERN Document Server

    2017-01-01

    This book serves as a comprehensive, up-to-date reference about this cutting-edge laser technology and its many new and interesting developments. Various aspects and trends of Raman fiber lasers are described in detail by experts in their fields. Raman fiber lasers have progressed quickly in the past decade, and have emerged as a versatile laser technology for generating high power light sources covering a spectral range from visible to mid-infrared. The technology is already being applied in the fields of telecommunication, astronomy, cold atom physics, laser spectroscopy, environmental sensing, and laser medicine. This book covers various topics relating to Raman fiber laser research, including power scaling, cladding and diode pumping, cascade Raman shifting, single frequency operation and power amplification, mid-infrared laser generation, specialty optical fibers, and random distributed feedback Raman fiber lasers. The book will appeal to scientists, students, and technicians seeking to understand the re...

  18. Laser-surface interactions

    CERN Document Server

    Ganeev, Rashid A

    2014-01-01

    This book is about the interaction of laser radiation with various surfaces at variable parameters of radiation. As a basic principle of classification we chose the energetic or intensity level of interaction of laser radiation with the surfaces. These two characteristics of laser radiation are the most important parameters defining entire spectrum of the processes occurring on the surfaces during interaction with electromagnetic waves. This is a first book containing a whole spectrum of the laser-surface interactions distinguished by the ranges of used laser intensity. It combines the surface response starting from extremely weak laser intensities (~1 W cm-2) up to the relativistic intensities (~1020 W cm-2 and higher). The book provides the basic information about lasers and acquaints the reader with both common applications of laser-surface interactions (laser-related printers, scanners, barcode readers, discs, material processing, military, holography, medicine, etc) and unusual uses of the processes on t...

  19. Double conjugate laser amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, S.; Daunt, G.H.

    1991-01-29

    This paper describes a double conjugate laser amplifier system for producing a stable output laser beam in line with a laser oscillator input beam. It comprises: a laser oscillator which produces a low energy oscillator laser beam therefrom directly along a laser beam axis of the system; an amplification means comprised of double conjugate laser amplifiers further comprised of a first and a second singly phase conjugate amplifiers laterally opposite each other about the laser beam axis; polarizers with one of the polarizers positioned between each of the first and second singly phase conjugate amplifiers on the laser beam axis; Pockels cells with on of the Pockels cells positioned on the laser beam axis immediately prior to one of the polarizers; and a means for selectively switching the amplifier means comprised of applying a half-wave voltage at each of the Pockels cells to provide a polarization rotation of the input beam through 90{degrees} for routing of the oscillator laser beam directly through or reflected off the polarizes as an input beam to the amplification means wherein the amplification means amplifies the input beam twice in each of the first and second singly phase conjugate amplifiers and reflects the amplified laser beam off the polarizers as an amplified laser output beam in exactly the same direction as the input laser beam.

  20. Lasers in periodontics.

    Science.gov (United States)

    Elavarasu, Sugumari; Naveen, Devisree; Thangavelu, Arthiie

    2012-08-01

    Laser is one of the most captivating technologies in dental practice since Theodore Maiman in 1960 invented the ruby laser. Lasers in dentistry have revolutionized several areas of treatment in the last three and a half decades of the 20(th) century. Introduced as an alternative to mechanical cutting device, laser has now become an instrument of choice in many dental applications. Evidence suggests its use in initial periodontal therapy, surgery, and more recently, its utility in salvaging implant opens up a wide range of applications. More research with better designs are a necessity before lasers can become a part of dental armamentarium. This paper gives an insight to laser in periodontics.

  1. Laser materials processing with diode lasers

    OpenAIRE

    Li, Lin; Lawrence, Jonathan; Spencer, Julian T.

    1996-01-01

    Laser materials processing is currently dominated by CO2, Nd-YAG and Excimer lasers. Continuous advances in semiconductor laser technology over the last decade have increased the average power output of the devices annualy by two fold, resulting in the commercial availability of the diode lasers today with delivery output powers in excess of 60W in CW mode and 5kW in qasi-CW mode. The advantages of compactness, high reliability, high efficiency and potential low cost, due to the mass producti...

  2. Analysis of High-Power Diode Laser Heating Effects on HY-80 Steel for Laser Assisted Friction Stir Welding Applications

    Energy Technology Data Exchange (ETDEWEB)

    Wiechec, Maxwell; Baker, Brad; McNelley, Terry; Matthews, Manyalibo; Rubenchik, Alexander; Rotter, Mark; Beach, Ray; Wu, Sheldon

    2017-01-01

    In this research, several conditions of high power diode laser heated HY-80 steel were characterized to determine the viability of using such lasers as a preheating source before friction stir welding in order to reduce frictional forces thereby reducing tool wear and increasing welding speeds. Differences in microstructures within heat affected zones were identified at specific laser powers and traverse speeds. Vickers hardness values were recorded and analyzed to validate the formation of additional martensite in diode laser heated regions of HY-80 steel. Conditions that produced little to no additional martensite were identified and relationships among high power diode laser power, traverse speed, and martensite formation were determined. The development of heat affected zones, change in grain structure, and creation of additional martensite in HY-80 can be prevented through the optimization of laser amperage and transverse speed.

  3. Lithium triborate laser vaporization of the prostate using the 120 W, high performance system laser: high performance all the way?

    Science.gov (United States)

    Hermanns, Thomas; Strebel, Daniel D; Hefermehl, Lukas J; Gross, Oliver; Mortezavi, Ashkan; Müller, Alexander; Eberli, Daniel; Müntener, Michael; Michel, Maurice S; Meier, Alexander H; Sulser, Tullio; Seifert, Hans-Helge

    2011-06-01

    Technical modifications of the 120 W lithium-triborate laser have been implemented to increase power output, and prevent laser fiber degradation and loss of power output during laser vaporization of the prostate. However, visible alterations at the fiber tip and the subjective impression of decreasing ablative effectiveness during lithium-triborate laser vaporization indicate that delivering constantly high laser power remains a relevant problem. Thus, we evaluated the extent of laser fiber degradation and loss of power output during 120 W lithium-triborate laser vaporization of the prostate. We investigated 46 laser fibers during routine 120 W lithium-triborate laser vaporization in 35 patients with prostatic bladder outflow obstruction. Laser beam power was measured at baseline and after the application of each 25 kJ during laser vaporization. Fiber tips were microscopically examined after the procedure. Mild to moderate degradation at the emission window occurred in all fibers, associated with a loss of power output. A steep decrease to a median power output of 57.3% of baseline was detected after applying the first 25 kJ. Median power output at the end of the defined 275 kJ lifespan of the fibers was 48.8%. Despite technical refinements of the 120 W lithium-triborate laser fiber degradation and significantly decreased power output are still detectable during the procedure. Laser fibers are not fully appropriate for the high power delivery of the new system. There is still potential for further improvement in the laser performance. Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  4. Potential mechanism for the laser-fluoride effect on enamel demineralization.

    Science.gov (United States)

    Liu, Y; Hsu, C-Y S; Teo, C M J; Teoh, S H

    2013-01-01

    Laser-induced prevention of dental caries has been studied extensively. However, the cariostatic mechanisms of a combined fluoride-laser treatment are not well-understood. Using micro- computed tomography (micro-CT), we quantified the effect of fluoride and/or Er:YAG laser treatment on enamel demineralization. The mean mineral loss (%/V) for each group was 4,870 ± 1,434 (fluoride followed by laser treatment), 6,341 ± 2,204 (laser treatment), 7,669 ± 2,255 (fluoride treatment), and 10,779 ± 2,936 (control). The preventive effect of the laser (p enamel hydroxyapatite into fluoridated hydroxyapatite to reduce enamel solubility as a preventive treatment for enamel demineralization.

  5. Photonic bandgap fiber lasers and multicore fiber lasers for next generation high power lasers

    DEFF Research Database (Denmark)

    Shirakawa, A.; Chen, M.; Suzuki, Y.

    2014-01-01

    Photonic bandgap fiber lasers are realizing new laser spectra and nonlinearity mitigation that a conventional fiber laser cannot. Multicore fiber lasers are a promising tool for power scaling by coherent beam combination. © 2014 OSA....

  6. Laser surgery - skin

    Science.gov (United States)

    Surgery using a laser ... used is directly related to the type of surgery being performed and the color of the tissue ... Laser surgery can be used to: Close small blood vessels to reduce blood loss Remove warts , moles , sunspots, and ...

  7. Wavelength sweepable laser source

    DEFF Research Database (Denmark)

    2014-01-01

    Wavelength sweepable laser source is disclosed, wherein the laser source is a semiconductor laser source adapted for generating laser light at a lasing wavelength. The laser source comprises a substrate, a first reflector, and a second reflector. The first and second reflector together defines...... and having a rest position, the second reflector and suspension together defining a microelectromechanical MEMS oscillator. The MEMS oscillator has a resonance frequency and is adapted for oscillating the second reflector on either side of the rest position.; The laser source further comprises electrical...... connections adapted for applying an electric field to the MEMS oscillator. Furthermore, a laser source system and a method of use of the laser source are disclosed....

  8. Laser safety in dentistry.

    Science.gov (United States)

    Sweeney, Caroline

    2008-01-01

    Although many regulations and standards relating to laser safety are in effect, there continue to be an average of 35 laser injuries per year. Laser safety professionals believe that this number under-represents the actual number of injuries and that many more accidents per year occur that are not documented with federal agencies. A review of these accidents has determined that failing to wear available eye protection is one of the most frequent contributing factors to laser injuries. As the purchase and use of lasers in dentistry continues to grow, so must concern for laser safety. This article provides basic information to advance the safe use of lasers in dentistry and to help establish laser safety protocols for the dental office.

  9. Transmyocardial Laser Revascularization

    Science.gov (United States)

    ... Vascular Access for Hemodialysis Ventricular Assist Devices Transmyocardial Laser Revascularization Like every other organ or tissue in ... bypass surgery, there is a procedure called transmyocardial laser revascularization, also called TMLR or TMR. TMLR cannot ...

  10. Laser particle sorter

    Science.gov (United States)

    Martin, J.C.; Buican, T.N.

    1987-11-30

    Method and apparatus are provided for sorting particles, such as biological particles. A first laser is used to define an optical path having an intensity gradient which is effective to propel the particles along the path but which is sufficiently weak that the particles are not trapped in an axial direction. A probe laser beam is provided for interrogating the particles to identify predetermined phenotypical characteristics of the particles. A second laser beam is provided to intersect the driving first laser beam, wherein the second laser beam is activated by an output signal indicative of a predetermined characteristic. The second laser beam is switchable between a first intensity and a second intensity, where the first intensity is effective to displace selected particles from the driving laser beam and the second intensity is effective to propel selected particles along the deflection laser beam. The selected particles may then be propelled by the deflection beam to a location effective for further analysis. 2 figs.

  11. Laser-assisted electrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Glenn, D.F.

    1995-05-01

    The effect of laser irradiation on electrodeposition processes has been investigated. These studies demonstrated that the addition of laser irradiation to an electroplating process can dramatically enhance plating rates and current efficiencies, as well as improve the morphology of the resultant electrodeposit. During the course of these investigations, the mechanism for the laser enhancement of electrodeposition processes was determined. Experimental evidence was obtained to show that laser irradiation of the substrate results in increased metal ion concentrations at the surface of the electrode due to a laser-induced Soret effect. The laser-induced Soret effect has important implications for laser-assisted electrochemical processing. The increase in the surface concentration of ions allows efficient electrodeposition from dilute solutions. As such, laser- assisted electrodeposition may develop into an environmentally conscious manufacturing process by reducing waste and limiting worker exposure to toxic chemicals.

  12. Laser Processing and Chemistry

    CERN Document Server

    Bäuerle, Dieter

    2011-01-01

    This book gives an overview of the fundamentals and applications of laser-matter interactions, in particular with regard to laser material processing. Special attention is given to laser-induced physical and chemical processes at gas-solid, liquid-solid, and solid-solid interfaces. Starting with the background physics, the book proceeds to examine applications of lasers in “standard” laser machining and laser chemical processing (LCP), including the patterning, coating, and modification of material surfaces. This fourth edition has been enlarged to cover the rapid advances in the understanding of the dynamics of materials under the action of ultrashort laser pulses, and to include a number of new topics, in particular the increasing importance of lasers in various different fields of surface functionalizations and nanotechnology. In two additional chapters, recent developments in biotechnology, medicine, art conservation and restoration are summarized. Graduate students, physicists, chemists, engineers, a...

  13. Lasers in Electronic Warfare

    Science.gov (United States)

    Manke, Gerald C.

    2014-10-01

    The use of lasers for Electronic Warfare applications will be discussed and reviewed. Specific examples of deployed EW systems which include lasers will be presented along with a discussion of their most salient features.

  14. LASIK - Laser Eye Surgery

    Science.gov (United States)

    ... Uveitis Focus On Pediatric Ophthalmology Education Center Oculofacial Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center ... Glaucoma Education Center Pediatric Ophthalmology Education Center Oculofacial Plastic ... Center Laser Surgery Education Center Redmond Ethics Center ...

  15. Laser ablation of hard tissue: correlation between the laser beam parameters and the post-ablative tissue characteristics

    Science.gov (United States)

    Serafetinides, Alexandros A.; Makropoulou, Mersini I.; Khabbaz, Maruan

    2003-11-01

    Hard dental tissue laser applications, such as preventive treatment, laser diagnosis of caries, laser etching of enamel, laser decay removal and cavity preparation, and more recently use of the laser light to enlarge the root canal during the endodontic therapy, have been investigated for in vitro and in vivo applications. Post-ablative surface characteristics, e.g. degree of charring, cracks and other surface deformation, can be evaluated using scanning electron microscopy. The experimental data are discussed in relevance with the laser beam characteristics, e.g. pulse duration, beam profile, and the beam delivery systems employed. Techniques based on the laser illumination of the dental tissues and the subsequent evaluation of the scattered fluorescent light will be a valuable tool in early diagnosis of tooth diseases, as carious dentin or enamel. The laser induced autofluorescence signal of healthy dentin is much stronger than that of the carious dentin. However, a better understanding of the transmission patterns of laser light in teeth, for both diagnosis and therapy is needed, before the laser procedures can be used in a clinical environment.

  16. Laser Micromachining of Ceramics

    OpenAIRE

    SCITI, Diletta; Bellosi, Alida

    2011-01-01

    Laser surface processing of ceramics is an area of considerable technological importance for several structural, tribological, optical and electronic applications. The laser beam behaves as a heat source that induces a temperature rise on the surface and within the bulk of the material. Depending on laser parameters and material characteristics, lasers can be used for fabricating microholes at designated locations, for cutting, scribing, for surface modifications In this work different types ...

  17. Tunable laser optics

    CERN Document Server

    Duarte, FJ

    2015-01-01

    This Second Edition of a bestselling book describes the optics and optical principles needed to build lasers. It also highlights the optics instrumentation necessary to characterize laser emissions and focuses on laser-based optical instrumentation. The book emphasizes practical and utilitarian aspects of relevant optics including the essential theory. This revised, expanded, and improved edition contains new material on tunable lasers and discusses relevant topics in quantum optics.

  18. Lasers in periodontics

    OpenAIRE

    Elavarasu, Sugumari; Naveen, Devisree; Thangavelu, Arthiie

    2012-01-01

    Laser is one of the most captivating technologies in dental practice since Theodore Maiman in 1960 invented the ruby laser. Lasers in dentistry have revolutionized several areas of treatment in the last three and a half decades of the 20 th century. Introduced as an alternative to mechanical cutting device, laser has now become an instrument of choice in many dental applications. Evidence suggests its use in initial periodontal therapy, surgery, and more recently, its utility in salvaging imp...

  19. Tunable high pressure lasers

    Science.gov (United States)

    Hess, R. V.

    1976-01-01

    Atmospheric transmission of high energy CO2 lasers is considerably improved by high pressure operation which, due to pressure broadening, permits tuning the laser lines off atmospheric absorption lines. Pronounced improvement is shown for horizontal transmission at altitudes above several kilometers and for vertical transmission through the entire atmosphere. Applications of tunable high pressure CO2 lasers to energy transmission and to remote sensing are discussed along with initial efforts in tuning high pressure CO2 lasers.

  20. Laser cutting system

    Science.gov (United States)

    Dougherty, Thomas J

    2015-03-03

    A workpiece cutting apparatus includes a laser source, a first suction system, and a first finger configured to guide a workpiece as it moves past the laser source. The first finger includes a first end provided adjacent a point where a laser from the laser source cuts the workpiece, and the first end of the first finger includes an aperture in fluid communication with the first suction system.

  1. Photonic bandgap fiber lasers and multicore fiber lasers for next generation high power lasers

    DEFF Research Database (Denmark)

    Shirakawa, A.; Chen, M.; Suzuki, Y.

    2014-01-01

    Photonic bandgap fiber lasers are realizing new laser spectra and nonlinearity mitigation that a conventional fiber laser cannot. Multicore fiber lasers are a promising tool for power scaling by coherent beam combination. © 2014 OSA.......Photonic bandgap fiber lasers are realizing new laser spectra and nonlinearity mitigation that a conventional fiber laser cannot. Multicore fiber lasers are a promising tool for power scaling by coherent beam combination. © 2014 OSA....

  2. Laser Stabilization with Laser Cooled Strontium

    DEFF Research Database (Denmark)

    Christensen, Bjarke Takashi Røjle

    the nonlinear effects from coupling of an optical cavity to laser cooled atoms having a narrow transition linewidth. Here, we have realized such a system where a thermal sample of laser cooled strontium-88 atoms are coupled to an optical cavity. The strontium-88 atoms were probed on the narrow 1S0-3P1 inter...

  3. LaserFest Celebration

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Alan Chodos; Elizabeth A. Rogan

    2011-08-25

    LaserFest was the yearlong celebration, during 2010, of the 50th anniversary of the demonstration of the first working laser. The goals of LaserFest were: to highlight the impact of the laser in its manifold commercial, industrial and medical applications, and as a tool for ongoing scientific research; to use the laser as one example that illustrates, more generally, the route from scientific innovation to technological application; to use the laser as a vehicle for outreach, to stimulate interest among students and the public in aspects of physical science; to recognize and honor the pioneers who developed the laser and its many applications; to increase awareness among policymakers of the importance of R&D funding as evidenced by such technology as lasers. One way in which LaserFest sought to meet its goals was to encourage relevant activities at a local level all across the country -- and also abroad -- that would be identified with the larger purposes of the celebration and would carry the LaserFest name. Organizers were encouraged to record and advertise these events through a continually updated web-based calendar. Four projects were explicitly detailed in the proposals: 1) LaserFest on the Road; 2) Videos; 3) Educational material; and 4) Laser Days.

  4. Lasers for nonlinear microscopy.

    Science.gov (United States)

    Wise, Frank

    2013-03-01

    Various versions of nonlinear microscopy are revolutionizing the life sciences, almost all of which are made possible because of the development of ultrafast lasers. In this article, the main properties and technical features of short-pulse lasers used in nonlinear microscopy are summarized. Recent research results on fiber lasers that will impact future instruments are also discussed.

  5. Fiber Lasers V

    DEFF Research Database (Denmark)

    Hansen, Kim P.; Olausson, Christina Bjarnal Thulin; Broeng, Jes

    2008-01-01

    High-power fiber lasers and amplifiers have gained tremendous momentum in the last five years, and many of the traditional manufactures of gas and solid-state lasers are pursuing the attractive fiber-based systems, which are now displacing the old technology in many areas. High-power fiber laser ...

  6. Laser Programs Highlights 1998

    Energy Technology Data Exchange (ETDEWEB)

    Lowdermilk, H.; Cassady, C.

    1999-12-01

    This report covers the following topics: Commentary; Laser Programs; Inertial Confinement Fusion/National Ignition Facility (ICF/NIF); Atomic Vapor Laser Isotope Separation (AVLIS); Laser Science and Technology (LS&T); Information Science and Technology Program (IS&T); Strategic Materials Applications Program (SMAP); Medical Technology Program (MTP) and Awards.

  7. ALMDS laser system

    Science.gov (United States)

    Kushina, Mark E.; Heberle, Geoff; Hope, Michael; Hall, David; Bethel, Michael; Calmes, Lonnie K.

    2003-06-01

    The ALMDS (Airborne Laser Mine Detection System) has been developed utilizing a solid-state laser operating at 532nm for naval mine detection. The laser system is integrated into a pod that mounts externally on a helicopter. This laser, along with other receiver systems, enables detailed underwater bathymetry. CEO designs and manufactures the laser portion of this system. Arete Associates integrates the laser system into the complete LIDAR package that utilizes sophisticated streak tube detection technology. Northrop Grumman is responsible for final pod integration. The laser sub-system is comprised of two separate parts: the LTU (Laser Transmitter Unit) and the LEU (Laser Electronics Unit). The LTU and LEU are undergoing MIL-STD-810 testing for vibration, shock, temperature storage and operation extremes, as well as MIL-STD-704E electrical power testing and MIL-STD-461E EMI testing. The Nd:YAG MOPA laser operates at 350 Hz pulse repetition frequency at 45 Watts average 532nm power and is controlled at the system level from within the helicopter. Power monitor circuits allow real time laser health monitoring, which enables input parameter adjustments for consistent laser behavior.

  8. Compact Hybrid Laser Rod and Laser System

    Science.gov (United States)

    Busch, George E. (Inventor); Amzajerdian, Farzin (Inventor); Pierrottet, Diego F. (Inventor)

    2017-01-01

    A hybrid fiber rod includes a fiber core and inner and outer cladding layers. The core is doped with an active element. The inner cladding layer surrounds the core, and has a refractive index substantially equal to that of the core. The outer cladding layer surrounds the inner cladding layer, and has a refractive index less than that of the core and inner cladding layer. The core length is about 30 to 2000 times the core diameter. A hybrid fiber rod laser system includes an oscillator laser, modulating device, the rod, and pump laser diode(s) energizing the rod from opposite ends. The rod acts as a waveguide for pump radiation but allows for free-space propagation of laser radiation. The rod may be used in a laser resonator. The core length is less than about twice the Rayleigh range. Degradation from single-mode to multi-mode beam propagation is thus avoided.

  9. Laser in ophthalmology. Laser i oftalmologien

    Energy Technology Data Exchange (ETDEWEB)

    Syrdalen, P. (Rikshospitalet, Oslo (Norway))

    1991-09-01

    The article presents a brief history of the use of laser in ophthalmology in Norway, from the introduction of the first argon-photocoalulator in 1972 to the excimer laser in 1990. The argon-photocoagulator is in daily us in all Eye Departments in Norway and the main group of patients treated are those with diabetic retionopathy. Glaucoma has been treated with argon-laser with good results for the last ten years. YAG-laser, introduced in Norway in 1985, is used to treat secondary cataracts which occur after extracapsular cataract extractions and implantation of artificial lenses. In 1990, the excimer laser was introduced for refractive surgery (myopia, astigmatism). 4 refs., 6 figs., 1 tab.

  10. Diode laser and endoscopic laser surgery.

    Science.gov (United States)

    Sullins, Kenneth E

    2002-05-01

    Two functionally important differences exist between the diode laser and the carbon dioxide (CO2) laser (used more commonly in small animal surgery). Diode laser energy is delivered through a quartz fiber instead of being reflected through an articulated arm or waveguide. Quartz fibers are generally more flexible and resilient than waveguides and can be inserted through an endoscope for minimally invasive procedures. Laser-tissue interaction is the other significant difference. The CO2 laser is completely absorbed by water, which limits the effect to visible tissue. The diode wavelength is minimally absorbed by water and may affect tissue as deep as 10 mm below the surface in the free-beam mode. With proper respect for the tissue effect, these differences can be used to the advantage of the patient.

  11. Quantum well lasers

    CERN Document Server

    Zory, Jr, Peter S; Kelley, Paul

    1993-01-01

    This book provides the information necessary for the reader to achieve a thorough understanding of all aspects of QW lasers - from the basic mechanism of optical gain, through the current technolgoical state of the art, to the future technologies of quantum wires and quantum dots. In view of the growing importance of QW lasers, this book should be read by all those with an active interest in laser science and technology, from the advanced student to the experienced laser scientist.* The first comprehensive book-length treatment of quantum well lasers* Provides a detailed treatment

  12. Introduction to laser technology

    CERN Document Server

    Hitz, C Breck; Hecht, Jeff; Hitz, C Breck; John Wiley & Sons

    2001-01-01

    Electrical Engineering Introduction to Laser Technology , Third Edition. Would you like to know how a laser works, and how it can be modified for your own specific tasks? This intuitive third edition-previously published as Understanding Laser Technology , First and Second Editions-introduces engineers, scientists, technicians, and novices alike to the world of modern lasers, without delving into the mathematical details of quantum electronics. It is the only introductory text on the market today that explains the underlying physics and engineering applicable to all lasers. A unique combinatio.

  13. Tunable laser applications

    CERN Document Server

    Duarte, FJ

    2008-01-01

    Introduction F. J. Duarte Spectroscopic Applications of Tunable Optical Parametric Oscillators B. J. Orr, R. T. White, and Y. He Solid-State Dye Lasers Costela, I. García-Moreno, and R. Sastre Tunable Lasers Based on Dye-Doped Polymer Gain Media Incorporating Homogeneous Distributions of Functional Nanoparticles F. J. Duarte and R. O. James Broadly Tunable External-Cavity Semiconductor Lasers F. J. Duarte Tunable Fiber Lasers T. M. Shay and F. J. Duarte Fiber Laser Overview and Medical Applications

  14. Coherent laser beam combining

    CERN Document Server

    Brignon, Arnaud

    2013-01-01

    Recently, the improvement of diode pumping in solid state lasers and the development of double clad fiber lasers have allowed to maintain excellent laser beam quality with single mode fibers. However, the fiber output power if often limited below a power damage threshold. Coherent laser beam combining (CLBC) brings a solution to these limitations by identifying the most efficient architectures and allowing for excellent spectral and spatial quality. This knowledge will become critical for the design of the next generation high-power lasers and is of major interest to many industrial, environme

  15. Lasers in otorhinolaryngology

    Science.gov (United States)

    Pais Clemente, Manuel P.

    1992-03-01

    Lasers are now commonly accepted and widely used surgical instruments in otorhinolaryngology. There have been a great number of technological advances with lasers that have contributed to the expansion of this new surgical modality with an increased number of medical applications. Surgical strategies have also changed and are more favorable toward conservative surgery in which less tissues is removed than with more radical resections. This combination of improving technology and medical attitudes has changed the field of otorhinolaryngology, and resulted in an expanding use of laser surgery. Since 1973 we have been using the carbon dioxide laser in the treatment of diseases of the upper aero digestive systems, learning this new surgical technique from the pioneer work of Strong, Jako, and Vaughan. It is our conviction that a laser surgeon must have a thorough knowledge of laser biophysics, instrumentation, safety protocols, and surgical indications, and have the technical skills to perform laser surgery. Laser technology continues to improve at an increased speed, and it is imperative to update knowledge of current and potential applications of lasers in our specialty. It is the purpose of this article to present our clinical experience of 18 years with the use of lasers in surgery of ORL, emphasizing the carbon dioxide laser.

  16. Lasers in materials science

    CERN Document Server

    Ossi, Paolo; Zhigilei, Leonid

    2014-01-01

    This book covers various aspects of lasers in materials science, including a comprehensive overview on basic principles of laser-materials interactions and applications enabled by pulsed laser systems.  The material is organized in a coherent way, providing the reader with a harmonic architecture. While systematically covering the major current and emerging areas of lasers processing applications, the Volume provides examples of targeted modification of material properties achieved through careful control of the processing conditions and laser irradiation parameters. Special emphasis is placed on specific strategies aimed at nanoscale control of material structure and properties to match the stringent requirements of modern applications.  Laser fabrication of novel nanomaterials, which expands to the domains of photonics, photovoltaics, sensing, and biomedical applications, is also discussed in the Volume. This book assembles chapters based on lectures delivered at the Venice International School on Lasers...

  17. [Navigated retinal laser therapy].

    Science.gov (United States)

    Kernt, M; Ulbig, M; Kampik, A; Neubauer, A S

    2013-08-01

    Navigated laser therapy introduces for the first time computerized assistance systems for retinal laser therapy. The Navilas system offers high precision and safety and provides additional benefits regarding standardization of planning, execution, documentation and quality assurance. The current focus of clinical application for navigated laser therapy besides laser treatment after retinal vein occlusion and panretinal laser photocoagulation in proliferative diabetic retinopathy (PDR) is diabetic macular edema. Recent data indicate that combined initial anti-vascular endothelial growth factor (anti-VEGF) and navigated macular laser therapy allows achievement and maintenance of treatment success with a minimum number of interventions. Despite very promising results the current assessment of navigated laser therapy is still limited by the evidence available worldwide.

  18. Laser beam shaping techniques

    Energy Technology Data Exchange (ETDEWEB)

    DICKEY,FRED M.; WEICHMAN,LOUIS S.; SHAGAM,RICHARD N.

    2000-03-16

    Industrial, military, medical, and research and development applications of lasers frequently require a beam with a specified irradiance distribution in some plane. A common requirement is a laser profile that is uniform over some cross-section. Such applications include laser/material processing, laser material interaction studies, fiber injection systems, optical data image processing, lithography, medical applications, and military applications. Laser beam shaping techniques can be divided into three areas: apertured beams, field mappers, and multi-aperture beam integrators. An uncertainty relation exists for laser beam shaping that puts constraints on system design. In this paper the authors review the basics of laser beam shaping and present applications and limitations of various techniques.

  19. Laser safety in dentistry

    Science.gov (United States)

    Wigdor, Harvey A.

    1997-05-01

    One of the major causes of anxiety in the dental clinic is the dental handpiece. Because dentists wish to provide a method which can replace the drill there has often been a premature use of the laser in dentistry. Various lasers have been introduced into the clinic before research has shown the laser used is of clinical benefit. Any new treatment method must not compromise the health of the patient being treated. Thus a method of evaluating the clinical abilities of dentists and their understanding the limitations of the laser used must be developed. Dentist must be trained in the basic interaction of the laser on oral tissues. The training has to concentrate on the variation of the laser wavelength absorption in the different tissues of the oral cavity. Because of the differences in the optical properties of these tissues great care must be exercised by practitioners using lasers on patients.

  20. Lasers in periodontology.

    Science.gov (United States)

    Mavrogiannis, M; Thomason, J M; Seymour, R A

    2004-11-01

    Since the development of the ruby laser by Maiman in 1960, lasers have been widely employed in medicine for a number of years. The purpose of this paper is to summarize potential applications for lasers in dentistry, with special regard to periodontology. This article briefly describes clinical applications of lasers and laser safety. Particularly, the use of a diode laser seems to be promising, especially in already compromised transplant patients, who need to be treated with a technique where the operative and post-operative blood loss, post-operative discomfort and the recurrence of drug-induced gingival overgrowth need to be kept to a minimum or eliminated. Therefore, the use of lasers in periodontology may lead to an alteration in present clinical practice and help to establish the best management strategy because, by maintaining periodontal health, the life quality of patients can be improved.

  1. Lasers in oral surgery

    Science.gov (United States)

    Keller, Ulrich; Hibst, Raimund

    1994-12-01

    The indications of lasers in oral surgery are defined by the laser-tissue interaction types. These are mainly thermal effects depending especially on the absorption of laser light in varying biological tissues. In histological sections different laser effects are demonstrated on oral mucosa, bone and cartilage, which have a great influence on wound healing and subsequently on clinical indications of the different wavelengths. On the one hand the good coagulation effect of the Nd:YAG laser is wanted for hemostasis in soft tissue surgery. On the other hand, for the treatment of precancerous dysplasias or neoplasias an effective cutting with a coagulation effect like using the CO2 laser is necessary. However, the excision of benign mucosal lesions as well as performing osteotomies or shaping of cartilage should be undertaken with the Er:YAG laser without greater coagulation and consequently without any delay of wound healing.

  2. Laser Applications in Orthodontics

    Science.gov (United States)

    Heidari, Somayeh; Torkan, Sepideh

    2013-01-01

    A laser is a collimated single wavelength of light which delivers a concentrated source of energy. Soon after different types of lasers were invented, investigators began to examine the effects of different wavelengths of laser energy on oral tissues, routine dental procedures and experimental applications. Orthodontists, along with other specialist in different fields of dentistry, can now benefit from several different advantages that lasers provide during the treatment process, from the beginning of the treatment, when separators are placed, to the time of resin residues removal from the tooth surface at the end of orthodontic treatment. This article outlines some of the most common usages of laser beam in orthodontics and also provides a comparison between laser and other conventional method that were the standard of care prior to the advent of laser in this field. PMID:25606324

  3. Flexible Laser Metal Cutting

    DEFF Research Database (Denmark)

    Villumsen, Sigurd; Jørgensen, Steffen Nordahl; Kristiansen, Morten

    2014-01-01

    This paper describes a new flexible and fast approach to laser cutting called ROBOCUT. Combined with CAD/CAM technology, laser cutting of metal provides the flexibility to perform one-of-a-kind cutting and hereby realises mass production of customised products. Today’s laser cutting techniques...... possess, despite their wide use in industry, limitations regarding speed and geometry. Research trends point towards remote laser cutting techniques which can improve speed and geometrical freedom and hereby the competitiveness of laser cutting compared to fixed-tool-based cutting technology...... such as punching. This paper presents the concepts and preliminary test results of the ROBOCUT laser cutting technology, a technology which potentially can revolutionise laser cutting....

  4. Mode selection laser

    DEFF Research Database (Denmark)

    2014-01-01

    The invention relates to a semiconductor mode selection laser, particularly to a VCSEL laser (200) having mode selection properties. The mode selection capability of the laser is achieved by configuring one of the reflectors (15,51) in the resonance cavity so that a reflectivity of the reflector...... (15) varies spatially in one dimension or two dimensions. Accordingly, the reflector (15) with spatially varying reflectivity is part both of the resonance cavity and the mode selection functionality of the laser. A plurality of the lasers configured with different mode selectors, i.e. different...... spatial reflector variations, may be combined to generate a laser beam containing a plurality of orthogonal modes. The laser beam may be injected into a few- mode optical fiber, e.g. for the purpose of optical communication. The VCSEL may have intra-cavity contacts (31,37) and a Tunnel junction (33...

  5. Molecular dynamics stimulations to study laser dye aggregation in water (comparison with experiments); Simulations par dynamique moleculaire de la dimerisation de colorants laser en phase aqueuse (confrontation avec l'experience)

    Energy Technology Data Exchange (ETDEWEB)

    Dare-Doyen, St.; Doizi, D. [CEA Saclay, Dept. des Procedes d' Enrichissement (DCC/DPE/SPCP), 91 - Gif-sur-Yvette (France)

    2000-07-01

    A laser facility consists of dye laser chains where the active medium is composed of fluorescent dyes dissolved in ethanol. The use of water as a solvent would offer two major advantages: greater safety of the laser facility by drastically reducing fire risks, easier design of the laser beam correcting devices required at the end of the dye laser chains, thanks to the properties of water. Unfortunately, laser dyes exhibit poor optical properties in water, due to the formation of dye aggregates. Molecular dynamics simulations were used to study and develop means to prevent this behavior between two charged species. The results were compared with NMR (Nuclear Magnetic Resonance) experiments.

  6. Electron optical injection with head-on and countercrossing colliding laser pulses.

    Science.gov (United States)

    Kotaki, H; Daito, I; Kando, M; Hayashi, Y; Kawase, K; Kameshima, T; Fukuda, Y; Homma, T; Ma, J; Chen, L-M; Esirkepov, T Zh; Pirozhkov, A S; Koga, J K; Faenov, A; Pikuz, T; Kiriyama, H; Okada, H; Shimomura, T; Nakai, Y; Tanoue, M; Sasao, H; Wakai, D; Matsuura, H; Kondo, S; Kanazawa, S; Sugiyama, A; Daido, H; Bulanov, S V

    2009-11-06

    A high stability electron bunch is generated by laser wakefield acceleration with the help of a colliding laser pulse. The wakefield is generated by a laser pulse; the second laser pulse collides with the first pulse at 180 degrees and at 135 degrees realizing optical injection of an electron bunch. The electron bunch has high stability and high reproducibility compared with single pulse electron generation. In the case of 180 degrees collision, special measures have been taken to prevent damage. In the case of 135 degrees collision, since the second pulse is countercrossing, it cannot damage the laser system.

  7. The development of laser surgery and medicine in China

    Science.gov (United States)

    Chen, Mingzhe

    2005-07-01

    acne scar, osmidrosis etc. For ophthalmology, excimer laser are used for myopia or hyperopia; argon green laser, krypton yellow laser are adopted in coagulation for retinal detachment and neovascularization etc. Lasers are often used for the canaliculoplasty in the lacrimal canal. Low level lasers had been used very often on the acupuncture points and for many chronic diseases. Intravascular low level laser irradiation adopting semiconductor lasers and He-Ne laser were reported to use for comatose patients, schizophrenia, vascular dementia, Alzeimer"s disease and coronary disease. Reports from laboratory studies in the field of low level laser demonstrated the stimulation effect on the cells and immunology system; inhibitory effect on proliferation; it improved the biomedical data in hemorrheology; promoted the spinal motor nerve cell function, axonal regeneration; increased epidermal Langerhams cell to improve the antigen function, increased myocardial capillary permeability. Intra-coronary low power red laser irradiation assisted coronary interventional therapy showed its prevention effect on restenosis. Studies about the effects of various kinds of lasers, their wavelength, power densities and doses on various kinds of tissues were reported.

  8. Laser system using ultra-short laser pulses

    Science.gov (United States)

    Dantus, Marcos [Okemos, MI; Lozovoy, Vadim V [Okemos, MI; Comstock, Matthew [Milford, MI

    2009-10-27

    A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal.

  9. Polio and Prevention

    Science.gov (United States)

    ... Photo Collections Videos Polio Today → Polio + Prevention Polio + Prevention Polio and prevention Polio is a crippling and ... a child for life. Learn more about polio + prevention The Virus The Vaccines The Communities Related resources ...

  10. Clinical use of lasers in caries diagnosis and therapy.

    Science.gov (United States)

    Chan, Ambrose

    2008-06-01

    Laser technology is now ubiquitous in science, business, the arts, the military, industry, telecommunications, entertainment and medicine. It is increasingly finding a useful place in dentistry to offer the potential for practical solutions to managing difficult clinical problems. Research into the clinical use of lasers in diagnostic and therapeutic dental procedures has escalated rapidly in recent years. Laser technology has revolutionized the treatment of dental caries. This article reviews the role of laser technology in the clinical management of caries, early caries diagnosis and treatment planning decision making, caries prevention, soft tissue management, fluorescence aided caries elimination and fluorescence feedback-controlled selective caries removal. Laser technology plays a vital role in enhancing caries diagnosis and therapy.

  11. Laser in dentistry: An innovative tool in modern dental practice

    Science.gov (United States)

    Verma, Sanjeev Kumar; Maheshwari, Sandhya; Singh, Raj Kumar; Chaudhari, Prabhat Kumar

    2012-01-01

    The term LASER is an acronym for ‘Light Amplification by the Stimulated Emission of Radiation’. As its first application in dentistry by Miaman, in 1960, the laser has seen various hard and soft tissue applications. In the last two decades, there has been an explosion of research studies in laser application. In hard tissue application, the laser is used for caries prevention, bleaching, restorative removal and curing, cavity preparation, dentinal hypersensitivity, growth modulation and for diagnostic purposes, whereas soft tissue application includes wound healing, removal of hyperplastic tissue to uncovering of impacted or partially erupted tooth, photodynamic therapy for malignancies, photostimulation of herpetic lesion. Use of the laser proved to be an effective tool to increase efficiency, specificity, ease, and cost and comfort of the dental treatment. PMID:23833485

  12. Pathogen reduction in human plasma using an ultrashort pulsed laser.

    Science.gov (United States)

    Tsen, Shaw-Wei D; Kingsley, David H; Kibler, Karen; Jacobs, Bert; Sizemore, Sara; Vaiana, Sara M; Anderson, Jeanne; Tsen, Kong-Thon; Achilefu, Samuel

    2014-01-01

    Pathogen reduction is a viable approach to ensure the continued safety of the blood supply against emerging pathogens. However, the currently licensed pathogen reduction techniques are ineffective against non-enveloped viruses such as hepatitis A virus, and they introduce chemicals with concerns of side effects which prevent their widespread use. In this report, we demonstrate the inactivation of both enveloped and non-enveloped viruses in human plasma using a novel chemical-free method, a visible ultrashort pulsed laser. We found that laser treatment resulted in 2-log, 1-log, and 3-log reductions in human immunodeficiency virus, hepatitis A virus, and murine cytomegalovirus in human plasma, respectively. Laser-treated plasma showed ≥70% retention for most coagulation factors tested. Furthermore, laser treatment did not alter the structure of a model coagulation factor, fibrinogen. Ultrashort pulsed lasers are a promising new method for chemical-free, broad-spectrum pathogen reduction in human plasma.

  13. Pathogen reduction in human plasma using an ultrashort pulsed laser.

    Directory of Open Access Journals (Sweden)

    Shaw-Wei D Tsen

    Full Text Available Pathogen reduction is a viable approach to ensure the continued safety of the blood supply against emerging pathogens. However, the currently licensed pathogen reduction techniques are ineffective against non-enveloped viruses such as hepatitis A virus, and they introduce chemicals with concerns of side effects which prevent their widespread use. In this report, we demonstrate the inactivation of both enveloped and non-enveloped viruses in human plasma using a novel chemical-free method, a visible ultrashort pulsed laser. We found that laser treatment resulted in 2-log, 1-log, and 3-log reductions in human immunodeficiency virus, hepatitis A virus, and murine cytomegalovirus in human plasma, respectively. Laser-treated plasma showed ≥70% retention for most coagulation factors tested. Furthermore, laser treatment did not alter the structure of a model coagulation factor, fibrinogen. Ultrashort pulsed lasers are a promising new method for chemical-free, broad-spectrum pathogen reduction in human plasma.

  14. Frequency comb swept lasers.

    Science.gov (United States)

    Tsai, Tsung-Han; Zhou, Chao; Adler, Desmond C; Fujimoto, James G

    2009-11-09

    We demonstrate a frequency comb (FC) swept laser and a frequency comb Fourier domain mode locked (FC-FDML) laser for applications in optical coherence tomography (OCT). The fiber-based FC swept lasers operate at a sweep rate of 1kHz and 120kHz, respectively over a 135nm tuning range centered at 1310nm with average output powers of 50mW. A 25GHz free spectral range frequency comb filter in the swept lasers causes the lasers to generate a series of well defined frequency steps. The narrow bandwidth (0.015nm) of the frequency comb filter enables a approximately -1.2dB sensitivity roll off over approximately 3mm range, compared to conventional swept source and FDML lasers which have -10dB and -5dB roll offs, respectively. Measurements at very long ranges are possible with minimal sensitivity loss, however reflections from outside the principal measurement range of 0-3mm appear aliased back into the principal range. In addition, the frequency comb output from the lasers are equally spaced in frequency (linear in k-space). The filtered laser output can be used to self-clock the OCT interference signal sampling, enabling direct fast Fourier transformation of the fringe signals, without the need for fringe recalibration procedures. The design and operation principles of FC swept lasers are discussed and designs for short cavity lasers for OCT and interferometric measurement applications are proposed.

  15. Photobiomodulation in laser surgery

    Science.gov (United States)

    Liu, Timon Cheng-Yi; Rong, Dong-Liang; Huang, Jin; Deng, Xiao-Yuan; Liu, Song-Hao

    2006-01-01

    Laser surgery provides good exposure with clear operating fields and satisfactory preliminary functional results. In contrast to conventional excision, it was found that matrix metalloproteinases and the tissue inhibitors of metalloproteinases -1 mRNA expression is higher, myofibroblasts appeared and disappeared slower in laser excision wounds. It has been suggested that the better anatomical and functional results achieved following laser cordectomy may be explained by the fact that such procedures result in better, more rapid healing processes to recover vocal cord for early glottic tumors and better. In this paper, the role of photobiomodulation in laser surgery will be discussed by the cultured monolayer normal human skin fibroblast model of the photobiomodulation of marginal irradiation of high intensity laser beam, the photobiomodulation related to the irradiated tissue, the biological information model of photobiomodulation and the animal models of laser surgery. Although high intensity laser beam is so intense that it destroys the irradiated cells or tissue, its marginal irradiation intensity is so low that there is photobiomodulation on non-damage cells to modulate the regeneration of partly damaged tissue so that the surgery of laser of different parameters results in different post-surgical recovery. It was concluded that photobiomodulation might play an important role in the long-term effects of laser surgery, which might be used to design laser surgery.

  16. Laser treatment in gynecology

    Science.gov (United States)

    de Riese, Cornelia

    2004-07-01

    This presentation is designed as a brief overview of laser use in gynecology, for non-medical researchers involved in development of new laser techniques. The literature of the past decade is reviewed. Differences in penetration, absorption, and suitable delivery media for the beams dictate clinical application. The use of CO2 laser in the treatment of uterine cervical intraepithelial lesions is well established and indications as well as techniques have not changed over 30 years. The Cochrane Systematic Review from 2000 suggests no obviously superior technique. CO2 laser ablation of the vagina is also established as a safe treatment modality for VAIN. CO2 laser permits treatment of lesions with excellent cosmetic and functional results. The treatment of heavy menstrual bleeding by destruction of the endometrial lining using various techniques has been the subject of a 2002 Cochran Database Review. Among the compared treatment modalities are newer and modified laser techniques. Conclusion by reviewers is that outcomes and complication profiles of newer techniques compare favorably with the gold standard of endometrial resection. The ELITT diode laser system is one of the new successful additions. CO2 laser is also the dominant laser type used with laparoscopy for ablation of endometriotic implants. Myoma coagulation or myolysis with Nd:Yag laser through the laparoscope or hysteroscope is a conservative treatment option. Even MRI guided percutaneous approaches have been described. No long-term data are available.

  17. Laser scanning laser diode photoacoustic microscopy system.

    Science.gov (United States)

    Erfanzadeh, Mohsen; Kumavor, Patrick D; Zhu, Quing

    2018-03-01

    The development of low-cost and fast photoacoustic microscopy systems enhances the clinical applicability of photoacoustic imaging systems. To this end, we present a laser scanning laser diode-based photoacoustic microscopy system. In this system, a 905 nm, 325 W maximum output peak power pulsed laser diode with 50 ns pulsewidth is utilized as the light source. A combination of aspheric and cylindrical lenses is used for collimation of the laser diode beam. Two galvanometer scanning mirrors steer the beam across a focusing aspheric lens. The lateral resolution of the system was measured to be ∼21 μm using edge spread function estimation. No averaging was performed during data acquisition. The imaging speed is ∼370 A-lines per second. Photoacoustic microscopy images of human hairs, ex vivo mouse ear, and ex vivo porcine ovary are presented to demonstrate the feasibility and potentials of the proposed system.

  18. Lasers in medicine

    Energy Technology Data Exchange (ETDEWEB)

    Peng Qian [Department of Pathology, Norwegian Radium Hospital, University of Oslo, Montebello, 0310 Oslo (Norway); Juzeniene, Asta; Moan, Johan [Department of Radiation Biology, Norwegian Radium Hospital, University of Oslo, Montebello, 0310 Oslo (Norway); Chen Jiyao [State Key Laboratory for Advanced Photonic Materials and Devices, Fudan University, 200433 Shanghai (China); Svaasand, Lars O [Department of Electronics and Telecommunications, Norwegian University of Science and Technology, O.S. Bragstads Plass 2A, 7491 Trondheim (Norway); Warloe, Trond; Giercksky, Karl-Erik [Department of Surgical Oncology, Norwegian Radium Hospital, University of Oslo, Montebello, 0310 Oslo (Norway)], E-mail: Qian.Peng@rr-research.no

    2008-05-15

    It is hard to imagine that a narrow, one-way, coherent, moving, amplified beam of light fired by excited atoms is powerful enough to slice through steel. In 1917, Albert Einstein speculated that under certain conditions atoms could absorb light and be stimulated to shed their borrowed energy. Charles Townes coined the term laser (light amplification by stimulated emission of radiation) in 1951. Theodore Maiman investigated the glare of a flash lamp in a rod of synthetic ruby, creating the first human-made laser in 1960. The laser involves exciting atoms and passing them through a medium such as crystal, gas or liquid. As the cascade of photon energy sweeps through the medium, bouncing off mirrors, it is reflected back and forth, and gains energy to produce a high wattage beam of light. Although lasers are today used by a large variety of professions, one of the most meaningful applications of laser technology has been through its use in medicine. Being faster and less invasive with a high precision, lasers have penetrated into most medical disciplines during the last half century including dermatology, ophthalmology, dentistry, otolaryngology, gastroenterology, urology, gynaecology, cardiology, neurosurgery and orthopaedics. In many ways the laser has revolutionized the diagnosis and treatment of a disease. As a surgical tool the laser is capable of three basic functions. When focused on a point it can cauterize deeply as it cuts, reducing the surgical trauma caused by a knife. It can vaporize the surface of a tissue. Or, through optical fibres, it can permit a doctor to see inside the body. Lasers have also become an indispensable tool in biological applications from high-resolution microscopy to subcellular nanosurgery. Indeed, medical lasers are a prime example of how the movement of an idea can truly change the medical world. This review will survey various applications of lasers in medicine including four major categories: types of lasers, laser

  19. Dermatological laser treatment. Dermatologisk laserbehandling

    Energy Technology Data Exchange (ETDEWEB)

    Moerk, N.J.; Austad, J. (Rikshospitalet, Oslo (Norway)); Helland, S. (Haukeland Sykehus, Bergen (Norway)); Thune, P. (Ullevaal Sykehus, Oslo (Norway)); Volden, G. (University and Regional Hospital, Trondheim (Norway)); Falk, E. (University and Regional Hospital, Tromsoe (Norway))

    1991-10-01

    The article reviews the different lasers used in dermatology. Special emphasis is placed on the treatment of naevus flammeus (''portwine stain'') where lasers are the treatment of choice. Argon laser and pulsed dye laser are the main lasers used in vascular skin diseases, and the article focuses on these two types. Copper-vapour laser, neodymium-YAG laser and CO{sub 2} laser are also presented. Information is provided about the availability of laser technology in the different health regions in Norway. 5 refs., 2 figs.

  20. High power lasers in manufacturing

    OpenAIRE

    Chatwin, Chris R

    2017-01-01

    Lecture covers a brief history of lasers and the important beam parameters for manufacturing applications. It introduces the main laser types that are appropriate for manufacturing: carbon dioxide lasers, Nd YAG, Diode and fibre lasers, excimer lasers. It then looks at applications to different products and also micro-engineering

  1. Sub-Doppler laser cooling of potassium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Landini, M. [LENS and Dipartimento di Fisica e Astronomia, Universita di Firenze, I-50019 Sesto Fiorentino (Italy); INFN, Sezione di Firenze, I-50019 Sesto Fiorentino (Italy); Dipartimento di fisica, Universita di Trento, I-38123 Povo (Trento) (Italy); Roy, S.; Carcagni, L.; Trypogeorgos, D. [LENS and Dipartimento di Fisica e Astronomia, Universita di Firenze, I-50019 Sesto Fiorentino (Italy); Fattori, M.; Inguscio, M.; Modugno, G. [LENS and Dipartimento di Fisica e Astronomia, Universita di Firenze, I-50019 Sesto Fiorentino (Italy); INFN, Sezione di Firenze, I-50019 Sesto Fiorentino (Italy)

    2011-10-15

    We investigate the sub-Doppler laser cooling of bosonic potassium isotopes, whose small hyperfine splitting has so far prevented cooling below the Doppler temperature. We find instead that the combination of a dark optical molasses scheme that naturally arises in this kind of system and an adiabatic ramping of the laser parameters allows us to reach sub-Doppler temperatures for small laser detunings. We demonstrate temperatures as low as 25{+-}3 {mu}K and 47{+-}5 {mu}K in high-density samples of the two isotopes {sup 39}K and {sup 41}K, respectively. Our findings should find application to other atomic systems.

  2. Nuclear-pumped lasers

    CERN Document Server

    Prelas, Mark

    2016-01-01

    This book focuses on Nuclear-Pumped Laser (NPL) technology and provides the reader with a fundamental understanding of NPLs, a review of research in the field, and exploration of large scale NPL system design and applications. Early chapters look at the fundamental properties of lasers, nuclear-pumping and nuclear reactions that may be used as drivers for nuclear-pumped lasers. The book goes on to explore the efficient transport of energy from the ionizing radiation to the laser medium and then the operational characteristics of existing nuclear-pumped lasers. Models based on Mathematica, explanations and a tutorial all assist the reader’s understanding of this technology. Later chapters consider the integration of the various systems involved in NPLs and the ways in which they can be used, including beyond the military agenda. As readers will discover, there are significant humanitarian applications for high energy/power lasers, such as deflecting asteroids, space propulsion, power transmission and mining....

  3. Power Laser Ablation Symposia

    CERN Document Server

    Phipps, Claude

    2007-01-01

    Laser ablation describes the interaction of intense optical fields with matter, in which atoms are selectively driven off by thermal or nonthermal mechanisms. The field of laser ablation physics is advancing so rapidly that its principal results are seen only in specialized journals and conferences. This is the first book that combines the most recent results in this rapidly advancing field with authoritative treatment of laser ablation and its applications, including the physics of high-power laser-matter interaction. Many practical applications exist, ranging from inertial confinement fusion to propulsion of aerostats for pollution monitoring to laser ignition of hypersonic engines to laser cleaning nanoscale contaminants in high-volume computer hard drive manufacture to direct observation of the electronic or dissociative states in atoms and molecules, to studying the properties of materials during 200kbar shocks developed in 200fs. Selecting topics which are representative of such a broad field is difficu...

  4. Single frequency semiconductor lasers

    CERN Document Server

    Fang, Zujie; Chen, Gaoting; Qu, Ronghui

    2017-01-01

    This book systematically introduces the single frequency semiconductor laser, which is widely used in many vital advanced technologies, such as the laser cooling of atoms and atomic clock, high-precision measurements and spectroscopy, coherent optical communications, and advanced optical sensors. It presents both the fundamentals and characteristics of semiconductor lasers, including basic F-P structure and monolithic integrated structures; interprets laser noises and their measurements; and explains mechanisms and technologies relating to the main aspects of single frequency lasers, including external cavity lasers, frequency stabilization technologies, frequency sweeping, optical phase locked loops, and so on. It paints a clear, physical picture of related technologies and reviews new developments in the field as well. It will be a useful reference to graduate students, researchers, and engineers in the field.

  5. Lasers in periodontics

    Directory of Open Access Journals (Sweden)

    Sugumari Elavarasu

    2012-01-01

    Full Text Available Laser is one of the most captivating technologies in dental practice since Theodore Maiman in 1960 invented the ruby laser. Lasers in dentistry have revolutionized several areas of treatment in the last three and a half decades of the 20 th century. Introduced as an alternative to mechanical cutting device, laser has now become an instrument of choice in many dental applications. Evidence suggests its use in initial periodontal therapy, surgery, and more recently, its utility in salvaging implant opens up a wide range of applications. More research with better designs are a necessity before lasers can become a part of dental armamentarium. This paper gives an insight to laser in periodontics.

  6. Nanofabrication with Pulsed Lasers

    Directory of Open Access Journals (Sweden)

    Kabashin AV

    2010-01-01

    Full Text Available Abstract An overview of pulsed laser-assisted methods for nanofabrication, which are currently developed in our Institute (LP3, is presented. The methods compass a variety of possibilities for material nanostructuring offered by laser–matter interactions and imply either the nanostructuring of the laser-illuminated surface itself, as in cases of direct laser ablation or laser plasma-assisted treatment of semiconductors to form light-absorbing and light-emitting nano-architectures, as well as periodic nanoarrays, or laser-assisted production of nanoclusters and their controlled growth in gaseous or liquid medium to form nanostructured films or colloidal nanoparticles. Nanomaterials synthesized by laser-assisted methods have a variety of unique properties, not reproducible by any other route, and are of importance for photovoltaics, optoelectronics, biological sensing, imaging and therapeutics.

  7. Principles of Lasers

    CERN Document Server

    Svelto, Orazio

    2010-01-01

    This new Fifth Edition of Principles of Lasers incorporates corrections to the previous edition. The text’s essential mission remains the same: to provide a wide-ranging yet unified description of laser behavior, physics, technology, and current applications. Dr. Svelto emphasizes the physical rather than the mathematical aspects of lasers, and presents the subject in the simplest terms compatible with a correct physical understanding. Praise for earlier editions: "Professor Svelto is himself a longtime laser pioneer and his text shows the breadth of his broad acquaintance with all aspects of the field … Anyone mastering the contents of this book will be well prepared to understand advanced treatises and research papers in laser science and technology." (Arthur L. Schawlow, 1981 Nobel Laureate in Physics) "Already well established as a self-contained introduction to the physics and technology of lasers … Professor Svelto’s book, in this lucid translation by David Hanna, can be strongly recommended for...

  8. Lasers in periodontics

    Science.gov (United States)

    Elavarasu, Sugumari; Naveen, Devisree; Thangavelu, Arthiie

    2012-01-01

    Laser is one of the most captivating technologies in dental practice since Theodore Maiman in 1960 invented the ruby laser. Lasers in dentistry have revolutionized several areas of treatment in the last three and a half decades of the 20th century. Introduced as an alternative to mechanical cutting device, laser has now become an instrument of choice in many dental applications. Evidence suggests its use in initial periodontal therapy, surgery, and more recently, its utility in salvaging implant opens up a wide range of applications. More research with better designs are a necessity before lasers can become a part of dental armamentarium. This paper gives an insight to laser in periodontics. PMID:23066266

  9. Laser rocket system analysis

    Science.gov (United States)

    Jones, W. S.; Forsyth, J. B.; Skratt, J. P.

    1979-01-01

    The laser rocket systems investigated in this study were for orbital transportation using space-based, ground-based and airborne laser transmitters. The propulsion unit of these systems utilizes a continuous wave (CW) laser beam focused into a thrust chamber which initiates a plasma in the hydrogen propellant, thus heating the propellant and providing thrust through a suitably designed nozzle and expansion skirt. The specific impulse is limited only by the ability to adequately cool the thruster and the amount of laser energy entering the engine. The results of the study showed that, with advanced technology, laser rocket systems with either a space- or ground-based laser transmitter could reduce the national budget allocated to space transportation by 10 to 345 billion dollars over a 10-year life cycle when compared to advanced chemical propulsion systems (LO2-LH2) of equal capability. The variation in savings depends upon the projected mission model.

  10. Laser/tissue interaction.

    Science.gov (United States)

    Dederich, D N

    1991-01-01

    When laser light impinges on tissue, it can reflect, scatter, be absorbed, or transmit to the surrounding tissue. Absorption controls to a great degree the extent to which reflection, scattering and transmission occur, and wavelength is the primary determinant of absorption. The CO2 laser is consistently absorbed by most materials and tissues and the Nd-YAG laser wavelength is preferentially absorbed in pigmented tissues. The factors which determine the initial tissue effect include the laser wavelength, laser power, laser waveform, tissue optical properties, and tissue thermal properties. There are almost an infinite number of combinations of these factors possible, many of which would result in unacceptable damage to the tissues. This underscores the need to thoroughly test any particular combination of these factors on the conceptual, in-vitro, and in-vivo level before a treatment is offered.

  11. Strong field laser physics

    CERN Document Server

    2008-01-01

    Since the invention of the laser in the 1960s, people have strived to reach higher intensities and shorter pulse durations. High intensities and ultrashort pulse durations are intimately related. Recent developments have shown that high intensity lasers also open the way to realize pulses with the shortest durations to date, giving birth to the field of attosecond science (1 asec = 10-18s). This book is about high-intensity lasers and their applications. The goal is to give an up to date introduction to the technology behind these laser systems and to the broad range of intense laser applications. These applications include AMO (atomic molecular and optical) physics, x-ray science, attosecond science, plasma physics and particle acceleration, condensed matter science and laser micromachining, and finally even high-energy physics.

  12. Atomic iodine laser

    Energy Technology Data Exchange (ETDEWEB)

    Fisk, G.A.; Gusinow, M.A.; Hays, A.K.; Padrick, T.D.; Palmer, R.E.; Rice, J.K.; Truby, F.K.; Riley, M.E.

    1978-05-01

    The atomic iodine photodissociation laser has been under intensive study for a number of years. The physics associated with this system is now well understood and it is possible to produce a 0.1 nsec (or longer) near-diffraction-limited laser pulse which can be amplified with negligible temporal distortion and little spatial deformation. The output of either a saturated or unsaturated amplifier consists of a high-fidelity near-diffraction-limited, energetic laser pulse. The report is divided into three chapters. Chapter 1 is a survey of the important areas affecting efficient laser operation and summarizes the findings of Chap. 2. Chapter 2 presents detailed discussions and evaluations pertinent to pumps, chemical regeneration, and other elements in the overall laser system. Chapter 3 briefly discusses those areas that require further work and the nature of the work required to complete the full-scale evaluation of the applicability of the iodine photodissociation laser to the inertial confinement program.

  13. Thermal behaviors of stainless steel tube based GeO2 ATR hollow fibers for transmitting CO2 laser radiations

    Science.gov (United States)

    Wang, Xu; Wang, Lin; Fu, Xiaohong; Jing, Chengbin; Yue, Fangyu; Yang, Pingxiong; Chu, Junhao

    2017-10-01

    The stainless steel (SUS) capillary tube attenuated total reflective (ATR) GeO2 hollow waveguide has advantages of low fabrication cost, strong mechanic strength and low transmission loss. It can find laser power delivery applications such as laser surgery, and material processing. However, the temperature rise of the operating waveguide may affect the laser delivery stability and the laser surgery safety. The thermal behaviors of the SUS ATR hollow fiber transmitting CO2 laser were investigated theoretically and experimentally in this work. Both theoretic simulations and experimental results disclose the periodic oscillatory behavior of the fiber temperature. The influence of input laser power on fiber temperature has been quantitatively discussed. A maximum input laser power of 23 W is predicted for laser surgery in which case the fiber temperature had better be lower than 47 °C to avoid tissue scalds. An input laser power smaller than 137 W is suggested preventing the fiber from being overheated (150 °C).

  14. Laser In Veterinary Medicine

    Science.gov (United States)

    Newman, Carlton; Jaggar, David H.

    1982-12-01

    Lasers have been used for some time now on animals for experimental purposes prior to their use in human medical and surgical fields. However the use of lasers in veterinary medicine and surgery per se is a recent development. We describe the application of high and low intensity laser technology in a general overview of the current uses, some limitations to its use and future needs for future inquiry and development.

  15. Lasers in orthodontics

    OpenAIRE

    Nalcaci, Ruhi; Cokakoglu, Serpil

    2013-01-01

    Many types of dental lasers are currently available that can be efficiently used for soft and hard tissue applications in the field of orthodontics. For achieving the desired effects in the target tissue, knowledge of laser characteristics such as power, wavelength and timing, is necessary. Laser therapy is advantageous because it often avoids bleeding, can be pain free, is non-invasive and is relatively quick. The high cost is its primary disadvantage. It is very important to take the necess...

  16. Polarization feedback laser stabilization

    Science.gov (United States)

    Esherick, P.; Owyoung, A.

    1987-09-28

    A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other. 4 figs.

  17. Laser precision microfabrication

    CERN Document Server

    Sugioka, Koji; Pique, Alberto

    2010-01-01

    Miniaturization and high precision are rapidly becoming a requirement for many industrial processes and products. As a result, there is greater interest in the use of laser microfabrication technology to achieve these goals. This book composed of 16 chapters covers all the topics of laser precision processing from fundamental aspects to industrial applications to both inorganic and biological materials. It reviews the sate of the art of research and technological development in the area of laser processing.

  18. Infrared diode lasers

    Science.gov (United States)

    Lo, Wayne

    1981-01-01

    This paper reviews the development of infrared diode lasers for automobile exhaust gas analysis and high resolution spectroscopy at the General Motors Research Laboratories. Advances in lead-salt crystal growth technology and laser fabrication techniques to achieve high temperature operation and wide frequency tuning range will be discussed. Recent developments in improving the long-term reliability of the laser will also be reviewed.

  19. Introduction to laser technology

    CERN Document Server

    Hitz, C Breck; Hecht, Jeff

    2012-01-01

    The only introductory text on the market today that explains the underlying physics and engineering applicable to all lasersAlthough lasers are becoming increasingly important in our high-tech environment, many of the technicians and engineers who install, operate, and maintain them have had little, if any, formal training in the field of electro-optics. This can result in less efficient usage of these important tools. Introduction to Laser Technology, Fourth Edition provides readers with a good understanding of what a laser is and what it can and cannot do. The book explains what types of las.

  20. Gigashot Optical Laser Demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    Deri, R. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-13

    The Gigashot Optical Laser Demonstrator (GOLD) project has demonstrated a novel optical amplifier for high energy pulsed lasers operating at high repetition rates. The amplifier stores enough pump energy to support >10 J of laser output, and employs conduction cooling for thermal management to avoid the need for expensive and bulky high-pressure helium subsystems. A prototype amplifier was fabricated, pumped with diode light at 885 nm, and characterized. Experimental results show that the amplifier provides sufficient small-signal gain and sufficiently low wavefront and birefringence impairments to prove useful in laser systems, at repetition rates up to 60 Hz.

  1. Lasers for Onychomycosis.

    Science.gov (United States)

    Gupta, Aditya K; Foley, Kelly A; Versteeg, Sarah G

    Many studies that have been recently published investigate the efficacy of laser treatment for onychomycosis. These studies support the current US Food and Drug Administration (FDA) approval of lasers for the 'temporary increase in clear nail'. Clear nail growth is an important treatment goal for patients; however, many do not realise that laser treatment is not a cure for onychomycosis. The current article briefly reviews why lasers may be theoretically effective in treating onychomycosis and critically reviews published laser studies for onychomycosis in light of the standards employed in drug trials. Treatment regimens, efficacy endpoints, and the unit of analysis (nails vs patients) vary widely among published laser studies. Complete cure, mycological cure, and clinical improvement rates in laser studies are not reported or use such disparate criteria that comparison among studies is not possible. The US FDA has recently published guidelines for the use of medical devices in clinical trial design for onychomycosis. Future laser studies should adopt the FDA's guidelines to allow for more consistency within the field and focus on the efficacy of lasers as monotherapy for onychomycosis.

  2. X-ray lasers

    CERN Document Server

    Elton, Raymond C

    2012-01-01

    The first in its field, this book is both an introduction to x-ray lasers and a how-to guide for specialists. It provides new entrants and others interested in the field with a comprehensive overview and describes useful examples of analysis and experiments as background and guidance for researchers undertaking new laser designs. In one succinct volume, X-Ray Lasers collects the knowledge and experience gained in two decades of x-ray laser development and conveys the exciting challenges and possibilities still to come._Add on for longer version of blurb_M>The reader is first introduced

  3. High power lasers

    CERN Document Server

    Niku-Lari, A

    1989-01-01

    The use of lasers for the working and treatment of materials is becoming increasingly common in industry. However, certain laser applications, for example, in welding, cutting and drilling, are more widely exploited than others. Whilst the potential of lasers for the surface treatment of metals is well recognised, in practice, this particular application is a relative newcomer. The 24 papers in this volume present the latest research and engineering developments in the use of lasers for processes such as surface melting, surface alloying and cladding, and machining, as well as discussing th

  4. Physics of semiconductor lasers

    CERN Document Server

    Mroziewicz, B; Nakwaski, W

    2013-01-01

    Written for readers who have some background in solid state physics but do not necessarily possess any knowledge of semiconductor lasers, this book provides a comprehensive and concise account of fundamental semiconductor laser physics, technology and properties. The principles of operation of these lasers are therefore discussed in detail with the interrelations between their design and optical, electrical and thermal properties. The relative merits of a large number of laser structures and their parameters are described to acquaint the reader with the various aspects of the semiconductor l

  5. Principles of laser dynamics

    CERN Document Server

    Khanin, YI

    1995-01-01

    This monograph summarizes major achievements in laser dynamics over the past three decades. The book begins with two introductory Chapters. Chapter 1 offers general considerations on quantum oscillators, formulates the requirements for the laser key elements and shows how these requirements are met in different laser systems. The second Chapter proposes the mathematical models used in semiclassical laser theory, discusses the approximations and simplifications in particular cases, and specifies the range of applicability of these models. In Chapters 3-5 attention is given primarily to the stea

  6. Tunable Microfluidic Dye Laser

    DEFF Research Database (Denmark)

    Olsen, Brian Bilenberg; Helbo, Bjarne; Kutter, Jörg Peter

    2003-01-01

    We present a tunable microfluidic dye laser fabricated in SU-8. The tunability is enabled by integrating a microfluidic diffusion mixer with an existing microfluidic dye laser design by Helbo et al. By controlling the relative flows in the mixer between a dye solution and a solvent......, the concentration of dye in the laser cavity can be adjusted, allowing the wavelength to be tuned. Wavelength tuning controlled by the dye concentration was demonstrated with macroscopic dye lasers already in 1971, but this principle only becomes practically applicable by the use of microfluidic mixing...

  7. Transscleral laser for ophthalmology

    Science.gov (United States)

    Pekarik, Alexander S.; Linnik, Leonid A.; Kadan, Victor N.

    1997-05-01

    Transscleral laser (YAG:Nd, (lambda) equals 1.06 micrometers ) for ophthalmology has been developed and assembled for pulse laser transscleral treatment of eyes structures by means of adaptive optical fibers tip. `Adaptivity' means that we have used some exactly defined levels of optical fiber tip contact pressure to eyes surface to replace intertissues liquid. Such kind of fiber tip permit us apply more laser irradiation power due to decreasing of laser beam absorption in the liquid of eyes tissue. The different laser power levels, pulse duration, exposure time have been considered in correspondence with many types of adaptive fiber optical tips to optimize both transscleral coagulation and cutting process. To exactly determine the dependencies of laser irradiation spatial distributions behind sclera via contact tips pressure levels we have used as a adequate enough model He-Ne laser and eyes tissue samples. Laser system consist of power supply, control unit, laser head with cooling system, adapter for different kind of optical fibers tips. All of the above has been mounted as one case.

  8. Lasers for Frontier Spectroscopy

    Science.gov (United States)

    Baldacchini, Giuseppe

    The first laser has been invented in 1960 by using the red light from a ruby crystal, and since then the laser field exploded almost exponentially, and thousands of different materials, in the state of solids, liquids, vapors, gases, plasmas, and elementary particles have lased up to now from less than I Å to more than 1 mm. Many of them have been used with outstanding results both in basic science, and in industrial and commercial applications, by changing for ever the same lifestyle of humankind. As far as spectroscopy is concerned, the laser light has started an unprecedented revolution because of its unique properties as monochromaticity, coherence, power, brightness and short-pulse regime, unrivaled by any other natural and artificial light source. Spectroscopy applications increased qualitatively and quantitatively with the laser sources themselves, and they are still proceeding in parallel with the moving of the laser field towards new territories. Apart the opening up of new regions of the electromagnetic spectrum, like the terahertz gap, and the outstanding increase of the output power which is giving rise to completely new spectroscopic effects, the improvement of laser sources and auxiliary equipment is producing a growth of traditional laser spectroscopy with superior resolution and sensitivity. Moreover, spectroscopic techniques and laser light contributed to the development of new chemical and physical processes which have been used to fabricate photonic materials with new spectroscopic properties enriching the laser field itself, in a virtuous cycle spectroscopy→aser→material and back to spectroscopy with no end in sight.

  9. Lasers in materials processing

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J.I.; Rockower, E.B.

    1981-01-01

    A status report on the uranium Laser Isotope Separation (LIS) Program at the Lawrence Livermore National Laboratory is presented. Prior to this status report, process economic analysis is presented so as to understand how the unique properties of laser photons can be best utilized in the production of materials and components despite the high cost of laser energy. The characteristics of potential applications that are necessary for success are identified, and those factors that have up to now frustrated attempts to find commercially viable laser induced chemical and physical process for the production of new or existing materials are pointed out.

  10. Laser adaptive holographic hydrophone

    Energy Technology Data Exchange (ETDEWEB)

    Romashko, R V; Kulchin, Yu N; Bezruk, M N; Ermolaev, S A [Institute of Automation and Control Processes, Far Eastern Branch of the Russian Academy of Sciences, Vladivostok (Russian Federation)

    2016-03-31

    A new type of a laser hydrophone based on dynamic holograms, formed in a photorefractive crystal, is proposed and studied. It is shown that the use of dynamic holograms makes it unnecessary to use complex optical schemes and systems for electronic stabilisation of the interferometer operating point. This essentially simplifies the scheme of the laser hydrophone preserving its high sensitivity, which offers the possibility to use it under a strong variation of the environment parameters. The laser adaptive holographic hydrophone implemented at present possesses the sensitivity at a level of 3.3 mV Pa{sup -1} in the frequency range from 1 to 30 kHz. (laser hydrophones)

  11. Laser Program annual report 1987

    Energy Technology Data Exchange (ETDEWEB)

    O' Neal, E.M.; Murphy, P.W.; Canada, J.A.; Kirvel, R.D.; Peck, T.; Price, M.E.; Prono, J.K.; Reid, S.G.; Wallerstein, L.; Wright, T.W. (eds.)

    1989-07-01

    This report discusses the following topics: target design and experiments; target materials development; laboratory x-ray lasers; laser science and technology; high-average-power solid state lasers; and ICF applications studies.

  12. Manifestation of unequal arm lengths of uranyl ions in luminescent and oscillating spectra of uranylsufates and molybdates

    Energy Technology Data Exchange (ETDEWEB)

    Serezhkin, V.N.; Serezhkina, L.B.; Fakeyeva, O.A.; Olikov, I.I.

    1981-12-01

    This study was undertaken to determine how the nonuniformity of uranyl ions established by x-ray studies of uranyl molybdate and sulfate is manifested in the luminescent and oscillating spectra of these compounds. IR absorption spectra were recorded from specimens prepared as tablets with KBr or suspensions in vaseline oil. Raman spectra were recorded using a helium-neon laser spectrometer. Luminescent spectra were recorded at 77 K using a mercury-quartz lamp as the excitation source. The data indicate the possibility of detecting nonuniform arm lengths in uranyl ions by analysis of the luminescent and oscillating spectra. However a final answer to this question requires comparison of the spectroscopic and structural characteristics of a broader range of compounds with asymmetrical uranium-oxygen bonds in the uranyl ions.

  13. High-speed and high-accuracy DNA sequencing by capillary gel electrophoresis in a simple, low cost instrument. Two-color peak-height encoded sequencing at 40 degrees C.

    Science.gov (United States)

    Lu, H; Arriaga, E; Chen, D Y; Dovichi, N J

    1994-10-07

    A low-cost DNA sequencer was constructed based on a single helium-neon laser. The two-color peak-height encoded sequencing protocol, based on the use of T7 DNA polymerase in a manganese buffer, was used to generate samples. Two termination reactions were performed. In the first, a TAMRA (applied Biosystems)-labeled primer was extended in the presence of ddATP and ddCTP. The amounts of dideoxynucleotides were adjusted to produce a 3:1 peak height ratio. Similarly, a ROX (Applied Biosystems)-labeled primer was extended in the presence of ddGTP and ddTTP; the amounts of dideoxynucleotides was adjusted to produce a 3:1 peak height ratio. The pooled fragments were separated on a 4% T LongRanger gel operated at 39 degrees C. Over 500 bases of sequence were generated in 50 min.

  14. Immunological criteria in risk assessment of nonionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Batanov, G.V.; Trifonov, S.I.

    1984-07-01

    A survey is presented of the use of immunological criteria in determining safety limits for nonionizing radiation, in view of occupational, medical and background exposure to various sources of electromagnetic radiation. Many components of the immune system have been shown to be very labile to various external factors and, although experimental and clinical data are quite limited, nonionizing radiation has been demonstrated to affect certain components. For example, irradiation with low power flux density microwaves (to 1 mW/cm/sup 2/) has been shown to enhance certain specific and nonspecific immune responses, while microwaves in the 1-10 mW/cm/sup 2/ range have been shown to be immunosuppressive. In addition, therapeutic-intensity argon, cadmium, helium-neon and chemical HF lasers have been shown to alter serum immunoglobulin levels and antibody reactivity. Other factors of the immune system found susceptible to nonionizing radiation include phagocytic activity, immune cell function, complement activity, antibody formation, etc. 30 references.

  15. [Characteristics of laser light].

    Science.gov (United States)

    Takac, S; Stojanović, S

    1999-01-01

    Laser is one of the greatest technical discoveries of the 20th century. It is important in basic sciences, but particularly in diagnosis and therapy of various pathologic conditions of human organism. It is electromagnetic radiation, not X-irradiation and, as such, it is not expected to produce new generation of iatrogenic malignancies. Laser falls between infrared and ultraviolet on the spectrum mainly in the visible light spectrum. Properties of laser light are: monochromacity (the same color), coherence (all of the light waves are in phase both spatially and temporally), collimation (all rays are parallel to each other and do not diverge significantly even over long distances). Lasers were first conceived by Einstein in 1917 when he wrote his "Zur Quantum Theorie der Strahlung" (the quantum theory of radiation) which enumerated concepts of stimulated and spontaneous emission and absorption. Drs. Arthur Schawlow and Charles Townes, in 1956, extended lasers into the optical frequency range and Maiman, in 1960, operated the first laser using ruby as the active medium (ruby laser). Laser is an acronym for Light Amplification by Stimulated Emission of Radiation. To understand the acronym, it is necessary to understand the basic physics of the atom. However, if the atom that is in the excited state is struck by another photon of energy before it returns to the ground state, two photons of equal frequency and energy, travelling in the same direction and in perfect spatial and temporal harmony, are produced. This phenomenon is termed stimulated emission of radiation. An external power source hyperexcites the atoms in the laser medium so that the number of atoms possessing upper energy levels exceeds the number of atoms in a power energy level, a condition termed a population inversion. This "pumping system" which imparts additional energy to the atoms may be optical, mechanical, or chemical. These atoms in a hyperexcited state spontaneously emit photons of light. The

  16. The KTP-(greenlight-) laser--principles and experiences.

    Science.gov (United States)

    Bachmann, Alexander; Ruszat, Robin

    2007-01-01

    The most recent advance in laser technology for transurethral prostatectomy is represented by the KTP laser. A potassium-titanyl-phosphate-(KTP-) crystal doubles the frequency of pulsed Neodymium: Yttrium-Aluminum-Garnet (Nd:YAG) laser energy to a 532 nm wavelength, which is in the green electromagnetic spectrum (Greenlight-laser) and is selectively absorbed by hemoglobin and not at all by water. Reducing the wavelength leads to a completely different interaction between laser beam and prostatic tissue. In contrast to the early clinical experiences with the Nd:YAG lasers in which vaporization was observed as a side-effect during the procedure, the new KTP laser offers an immediate and efficient vaporization, leading to real tissue ablation. Because of the instant and nearly complete absorption in blood, the depth in vascularized tissue such as prostate is only 0.8 mm. The superficial coagulation prevents the large tissue necrosis that is seen with the Nd:YAG laser, leading to long lasting irritative symptoms due to sloughing of necrotic tissue. Initial experiences, made with a 60W KTP system, demonstrated that the procedure was as effective as conventional transurethral resection of the prostate (TURP) with a lower intraoperative complication rate. In order to speed up vaporization of the prostate laser power has been increased to 80W. The 80W KTP laser combines the tissue debulking properties of TURP and the favourable safety profile of laser surgery. With the new 120W High Performance System, introduced in 2006, vaporization will become more powerful and faster. Initial reports are awaited.

  17. Laser Stabilization with Laser Cooled Strontium

    DEFF Research Database (Denmark)

    Christensen, Bjarke Takashi Røjle

    The frequency stability of current state-of-the-art stabilized clock lasers are limited by thermal fluctuations of the ultra-stable optical reference cavities used for their frequency stabilization. In this work, we study the possibilities for surpassing this thermal limit by exploiting the nonli......The frequency stability of current state-of-the-art stabilized clock lasers are limited by thermal fluctuations of the ultra-stable optical reference cavities used for their frequency stabilization. In this work, we study the possibilities for surpassing this thermal limit by exploiting...... the nonlinear effects from coupling of an optical cavity to laser cooled atoms having a narrow transition linewidth. Here, we have realized such a system where a thermal sample of laser cooled strontium-88 atoms are coupled to an optical cavity. The strontium-88 atoms were probed on the narrow 1S0-3P1 inter......-combination line at 689 nm in a strongly saturated regime. The dynamics of the atomic induced phase shift and absorption of the probe light were experimentally studied in details with the purpose of applications to laser stabilization. The atomic sample temperature was in the mK range which brought this system out...

  18. New laser amplifier improves laser Doppler interferometry

    Science.gov (United States)

    1986-02-01

    The design of a laser light amplifier developed to improve the ability of a laser Doppler interferometry system to measure the high velocities of explosion-driven objects or targets is described. The amplifier increases the laser light intensity and S/N ratio. A green coumarin dye is utilized as if the lasing medium for an argon-ion laser and a blue dye as the frequency shifter to improve coupling between the light-pump power source and lasing medium. The arrangement of amplifier components and the frequency characteristics of the flash lamps and dyes are examined. The design requirements for eliminating chirping and achieving acoustic isolation are discussed. The control of the thermal gradients which produce lens effect is analyzed. The selection of a proper dye concentration for uniform excitation across the active volume of the amplifier is studied; an excitation absorption length of three diameters of active cross section is utilized. In order to increase the amount of pumping light reaching the laser dye and to reduce the number of unwanted wavelengths a optical frequency shifter is employed. The amplifier produces enough light to observe two or more spots on the target, record data for up to 12 microsec, and have an accuracy of 0.5 pct.

  19. Laser Sintered Calcium Phosphate Bone

    National Research Council Canada - National Science Library

    Vail, Neil

    1999-01-01

    ...) technology selective laser sintering (SLS). BME has successfully implemented a pilot facility to fabricate calcium phosphate implants using anatomical data coupled with the selective laser sintering process...

  20. Laser safety tools and training

    CERN Document Server

    Barat, Ken

    2008-01-01

    Lasers perform many unique functions in a plethora of applications, but there are many inherent risks with this continually burgeoning technology. Laser Safety: Tools and Training presents simple, effective ways for users in a variety of facilities to evaluate the hazards of any laser procedure and ensure they are following documented laser safety standards.Designed for use as either a stand-alone volume or a supplement to Laser Safety Management, this text includes fundamental laser and laser safety information and critical laser use information rarely found in a single source. The first lase

  1. Controlled laser cleaning of artworks via low resolution plasma spectroscopy and linear correlation

    NARCIS (Netherlands)

    Lentjes, M.

    2007-01-01

    In this thesis a system has been developed to prevent polluted artworks for over-cleaning during laser cleaning. One method to monitor the laser cleaning process in-situ is spectroscopic analyzing of the in-process induced plasma emission. The characteristic plasma emission spectrum depends on the

  2. Erosion resistant anti-ice surfaces generated by ultra short laser pulses

    NARCIS (Netherlands)

    Del Cerro, D.A.; Römer, G.R.B.E.; Huis in't Veld, A.J.

    2010-01-01

    Wetting properties of a wide range of materials can be modified by accurate laser micromachining with ultra short laser pulses. Controlling the surface topography in a micro and sub-micrometer scale allows the generation of water-repellent surfaces, which remain dry and prevent ice accumulation

  3. Poison prevention: engineering in primary prevention.

    Science.gov (United States)

    Marcus, Steven Matthew

    2012-03-01

    Over the past 50 years we have seen improvements in outcomes of poisonings in the United States. I intend to discuss the approaches to prevention. I review various primary, secondary, and tertiary prevention strategies in relationship to poison prevention. We have made strong efforts in some ways, but our efforts in primary prevention have often been less than maximal. We propose requiring lockable medicine cabinets and lockable storage cabinets for dangerous substances.

  4. Infrared laser irradiation of dental enamel using submicrosecond laser pulses with and without an applied water layer: effect on bond strength to restorative materials

    Science.gov (United States)

    Sarma, Anupama V.; Staninec, Michal; Le, Charles Q.; Fried, Daniel

    2004-05-01

    Previous studies have shown that during IR laser irradiation at CO2 and Er:YAG laser wavelengths, residual particles of fused non-apatite calcium phosphate phases accumulate that may inhibit adhesion to restorative materials. A layer of water added to the enamel surface before ablation prevents the accumulation of such phases. The objective of this study was to investigate the influence of laser pulse duration and wavelength with and without the added water layer on the bond strength of composite to laser prepared enamel surfaces. The surfaces of bovine enamel were irradiated by three lasers systems: a 0.5-μs Er:YSGG laser. a 25-μs Er:YAG laser and a 5-μs TEA CO2 laser operating at 9.6-μm. A motion control system and a pressurized spray system incorporating a microprocessor controlled pulsed nozzle for water delivery, were used to ensure uniform treatment of the entire surface. There was no significant reduction in the shear-bond strength of enamel to composite for the shorter erbium laser pulses if a water-spray was not used, in contrast to previous results for the 200-μs free-running Er:YAG laser in which the water-spray resulted in significantly higher bond-strengths. Shear-bond strengths for both erbium laser systems were significantly higher than for the CO2 laser irradiated samples and the negative control (no acid-etch) but significantly lower than the positive control group (phosphoric acid-etch). The application of the water-spray markedly influenced the surface morphology for all three laser systems with the most uniform surface preparation being produced by the 25-μs Er:YAG laser and the 5-μs CO2 laser with the water-spray.

  5. Laser Wakefield Accelerators

    OpenAIRE

    Najmudin, Z.

    2017-01-01

    The one-dimensional wakefield generation equations are solved for increasing levels of non-linearity, to demonstrate how they contribute to the overall behaviour of a non-linear wakefield in a plasma. The effect of laser guiding is also studied as a way to increase the interaction length of a laser wakefield accelerator.

  6. Fine welding with lasers.

    Science.gov (United States)

    MacLellan, D

    2008-01-01

    The need for micro joining metallic alloys for surgical instruments, implants and advanced medical devices is driving a rapid increase in the implementation of laser welding technology in research, development and volume production. This article discusses the advantages of this welding method and the types of lasers used in the process.

  7. Learning about Lasers

    Science.gov (United States)

    Roberts, Larry

    2011-01-01

    The word laser is an acronym. It stands for Light Amplification by Stimulated Emission of Radiation. Lasers, invented in 1958, are used to cut and fuse materials, accurately survey long distances, communicate across fiber-optic phone lines, produce 3D pictures, make special effects, help navigation, and read bar codes for cash registers. A laser…

  8. (308 nm) excimer laser

    Indian Academy of Sciences (India)

    The UV lasers with high quantum energy photons directly break the atomic and molecular bonds within material. The photons in this spectral range are also capable of inducing photo- chemical reactions. Most solid materials have high absorption in the UV. The short pulses result in reducing interaction time between laser ...

  9. Laser applications in surgery.

    Science.gov (United States)

    Azadgoli, Beina; Baker, Regina Y

    2016-12-01

    In modern medicine, lasers are increasingly utilized for treatment of a variety of pathologies as interest in less invasive treatment modalities intensifies. The physics behind lasers allows the same basic principles to be applied to a multitude of tissue types using slight modifications of the system. Multiple laser systems have been studied within each field of medicine. The term "laser" was combined with "surgery," "ablation," "lithotripsy," "cancer treatment," "tumor ablation," "dermatology," "skin rejuvenation," "lipolysis," "cardiology," "atrial fibrillation (AF)," and "epilepsy" during separate searches in the PubMed database. Original articles that studied the application of laser energy for these conditions were reviewed and included. A review of laser therapy is presented. Laser energy can be safely and effectively used for lithotripsy, for the treatment of various types of cancer, for a multitude of cosmetic and reconstructive procedures, and for the ablation of abnormal conductive pathways. For each of these conditions, management with lasers is comparable to, and potentially superior to, management with more traditional methods.

  10. Coherent Polariton Laser

    Science.gov (United States)

    Kim, Seonghoon; Zhang, Bo; Wang, Zhaorong; Fischer, Julian; Brodbeck, Sebastian; Kamp, Martin; Schneider, Christian; Höfling, Sven; Deng, Hui

    2016-01-01

    The semiconductor polariton laser promises a new source of coherent light, which, compared to conventional semiconductor photon lasers, has input-energy threshold orders of magnitude lower. However, intensity stability, a defining feature of a coherent state, has remained poor. Intensity noise many times the shot noise of a coherent state has persisted, attributed to multiple mechanisms that are difficult to separate in conventional polariton systems. The large intensity noise, in turn, limits the phase coherence. Thus, the capability of the polariton laser as a source of coherence light is limited. Here, we demonstrate a polariton laser with shot-noise-limited intensity stability, as expected from a fully coherent state. This stability is achieved by using an optical cavity with high mode selectivity to enforce single-mode lasing, suppress condensate depletion, and establish gain saturation. Moreover, the absence of spurious intensity fluctuations enables the measurement of a transition from exponential to Gaussian decay of the phase coherence of the polariton laser. It suggests large self-interaction energies in the polariton condensate, exceeding the laser bandwidth. Such strong interactions are unique to matter-wave lasers and important for nonlinear polariton devices. The results will guide future development of polariton lasers and nonlinear polariton devices.

  11. Coherent Polariton Laser

    Directory of Open Access Journals (Sweden)

    Seonghoon Kim

    2016-03-01

    Full Text Available The semiconductor polariton laser promises a new source of coherent light, which, compared to conventional semiconductor photon lasers, has input-energy threshold orders of magnitude lower. However, intensity stability, a defining feature of a coherent state, has remained poor. Intensity noise many times the shot noise of a coherent state has persisted, attributed to multiple mechanisms that are difficult to separate in conventional polariton systems. The large intensity noise, in turn, limits the phase coherence. Thus, the capability of the polariton laser as a source of coherence light is limited. Here, we demonstrate a polariton laser with shot-noise-limited intensity stability, as expected from a fully coherent state. This stability is achieved by using an optical cavity with high mode selectivity to enforce single-mode lasing, suppress condensate depletion, and establish gain saturation. Moreover, the absence of spurious intensity fluctuations enables the measurement of a transition from exponential to Gaussian decay of the phase coherence of the polariton laser. It suggests large self-interaction energies in the polariton condensate, exceeding the laser bandwidth. Such strong interactions are unique to matter-wave lasers and important for nonlinear polariton devices. The results will guide future development of polariton lasers and nonlinear polariton devices.

  12. Microfluidic Dye Lasers

    DEFF Research Database (Denmark)

    Kristensen, Anders; Balslev, Søren; Gersborg-Hansen, Morten

    2006-01-01

    A technology for miniaturized, polymer based lasers, suitable for integration with planar waveguides and microfluidic networks is presented. The microfluidic dye laser device consists of a microfluidic channel with an embedded optical resonator. The devices are fabricated in a thin polymer film...

  13. Lasers in dental traumatology

    National Research Council Canada - National Science Library

    Olivi, G; Caprioglio, C; Genovese, M D

    2010-01-01

    ... connected to dental trauma, particularly in children. Furthermore, laser-assisted therapies drastically reduce the need for analgesics and anti- inflammatory medications compared with conventional procedures. Using laser equipment to obtain anaesthesia is another challenge, while the use of low power setting for desensitising tissue and to obtain anaesthesia is also an open field.

  14. Levitated droplet dye laser

    DEFF Research Database (Denmark)

    Azzouz, H.; Alkafadiji, L.; Balslev, Søren

    2006-01-01

    a high quality optical resonator. Our 750 nL lasing droplets consist of Rhodamine 6G dissolved in ethylene glycol, at a concentration of 0.02 M. The droplets are optically pumped at 532 nm light from a pulsed, frequency doubled Nd:YAG laser, and the dye laser emission is analyzed by a fixed grating...

  15. Laser processing of materials

    Indian Academy of Sciences (India)

    Light amplification by stimulated emission of radiation (laser) is a coherent and monochromatic beam of electromagnetic radiation that can propagate in a straight line with negligible divergence and occur in a wide range of wavelength, energy/power and beam-modes/configurations. As a result, lasers find wide applications ...

  16. Lasers in Orthodontics

    Directory of Open Access Journals (Sweden)

    Rajesh Jayantilal Kamdar

    2013-01-01

    Summary and conclusion: Incorporation of lasers in an orthodontic practice requires thorough learning process on the part of the orthodontist. Attending various workshops and certification programs will help in mastering the science and art of laser dentistry. Needless to say, proper case selection will pave way for the successful long-term result.

  17. CO2 laser resurfacing.

    Science.gov (United States)

    Fitzpatrick, R E

    2001-07-01

    The CO2 Laser offers a variety of unique features in resurfacing facial photodamage and acne scarring. These include hemostasis, efficient removal of the epidermis in a single pass, thermally induced tissue tightening, and safe, predictable tissue interaction. Knowledge of these mechanisms will result in the capability of using the CO2 laser effectively and safely whether the goal is superficial or deep treatment.

  18. Laser Interference Lithography

    NARCIS (Netherlands)

    van Wolferen, Hendricus A.G.M.; Abelmann, Leon; Hennessy, Theodore C.

    In this chapter we explain how submicron gratings can be prepared by Laser Interference Lithography (LIL). In this maskless lithography technique, the standing wave pattern that exists at the intersection of two coherent laser beams is used to expose a photosensitive layer. We show how to build the

  19. Laser biostimulation in pediatrics

    Science.gov (United States)

    Utz, Irina A.; Lagutina, L. E.; Tuchin, Valery V.

    1995-01-01

    In the present paper the method and apparatus for percutaneous laser irradiation of blood (PLIB) in vessels (veins) are described. Results of clinical investigations of biostimulating effects under PLIB by red laser light (633 nm) in Cubiti and Saphena Magna veins are presented.

  20. Laser energy conversion

    Science.gov (United States)

    Jalufka, N. W.

    1989-01-01

    The conversion of laser energy to other, more useful, forms is an important element of any space power transmission system employing lasers. In general the user, at the receiving sight, will require the energy in a form other than laser radiation. In particular, conversion to rocket power and electricity are considered to be two major areas where one must consider various conversion techniques. Three systems (photovoltaic cells, MHD generators, and gas turbines) have been identified as the laser-to-electricity conversion systems that appear to meet most of the criteria for a space-based system. The laser thruster also shows considerable promise as a space propulsion system. At this time one cannot predict which of the three laser-to-electric converters will be best suited to particular mission needs. All three systems have some particular advantages, as well as disadvantages. It would be prudent to continue research on all three systems, as well as the laser rocket thruster. Research on novel energy conversion systems, such as the optical rectenna and the reverse free-electron laser, should continue due to their potential for high payoff.

  1. Exciton laser rate equations

    Directory of Open Access Journals (Sweden)

    Garkavenko A. S.

    2011-08-01

    Full Text Available The rate equations of the exciton laser in the system of interacting excitons have been obtained and the inverted population conditions and generation have been derived. The possibility of creating radically new gamma-ray laser has been shown.

  2. Solid state laser

    Science.gov (United States)

    Rines, Glen A. (Inventor); Moulton, Peter F. (Inventor); Harrison, James (Inventor)

    1993-01-01

    A wavelength-tunable, injection-seeded, dispersion-compensated, dispersively-pumped solid state laser includes a lasing medium; a highly reflective mirror; an output coupler; at least one isosceles Brewster prism oriented to the minimum deviation angle between the medium and the mirror for directing light of different wavelengths along different paths; means for varying the angle of the highly reflective mirror relative to the light from at least one Brewster angle for selecting a predetermined laser operating wavelength; a dispersion compensation apparatus associated with the lasing medium; a laser injection seeding port disposed between the dispersion compensation apparatus and one of the mirror and coupler and including a reflective surface at an acute non-Brewster angle to the laser beam for introducing a seed input; a dispersion compensation apparatus associated with the laser medium including opposite chirality optical elements; the lasing medium including a pump surface disposed at an acute angle to the laser beam to define a discrete path for the pumping laser beam separate from the pumped laser beam.

  3. Laser hair removal pearls.

    Science.gov (United States)

    Tierney, Emily P; Goldberg, David J

    2008-03-01

    A number of lasers and light devices are now available for the treatment of unwanted hair. The goal of laser hair removal is to damage stem cells in the bulge of the follicle through the targeting of melanin, the endogenous chromophore for laser and light devices utilized to remove hair. The competing chromophores in the skin and hair, oxyhemoglobin and water, have a decreased absorption between 690 nm and 1000 nm, thus making this an ideal range for laser and light sources. Pearls of laser hair removal are presented in this review, focusing on four areas of recent development: 1 treatment of blond, white and gray hair; 2 paradoxical hypertrichosis; 3 laser hair removal in children; and 4 comparison of lasers and IPL. Laser and light-based technologies to remove hair represents one of the most exciting areas where discoveries by dermatologists have led to novel treatment approaches. It is likely that in the next decade, continued advancements in this field will bring us closer to the development of a more permanent and painless form of hair removal.

  4. Athermal laser launch telescopes

    NARCIS (Netherlands)

    Kamphues, F.G.; Henselmans, R.; Rijnveld, N.; Lemmen, M.H.J.; Doelman, N.J.; Nijkerk, M.D.

    2011-01-01

    ESO has developed a concept for a compact laser guide star unit for use in future Adaptive Optics (AO) systems. A small powerful laser is combined with a telescope that launches the beam, creating a single modular unit that can be mounted directly on a large telescope. This approach solves several

  5. Ceramic laser materials

    Science.gov (United States)

    Ikesue, Akio; Aung, Yan Lin

    2008-12-01

    The word 'ceramics' is derived from the Greek keramos, meaning pottery and porcelain. The opaque and translucent cement and clay often used in tableware are not appropriate for optical applications because of the high content of optical scattering sources, that is, defects. Recently, scientists have shown that by eliminating the defects, a new, refined ceramic material - polycrystalline ceramic - can be produced. This advanced ceramic material offers practical laser generation and is anticipated to be a highly attractive alternative to conventional glass and single-crystal laser technologies in the future. Here we review the history of the development of ceramic lasers, the principle of laser generation based on this material, some typical results achieved with ceramic lasers so far, and discuss the potential future outlook for the field.

  6. Regenerative similariton laser

    Directory of Open Access Journals (Sweden)

    Thibault North

    2016-05-01

    Full Text Available Self-pulsating lasers based on cascaded reshaping and reamplification (2R are capable of initiating ultrashort pulses despite the accumulation of large amounts of nonlinearities in all-fiber resonators. The spectral properties of pulses in self-similar propagation are compatible with cascaded 2R regeneration by offset filtering, making parabolic pulses suitable for the design of a laser of this recently introduced class. A new type of regenerative laser giving birth to similaritons is numerically investigated and shows that this laser is the analog of regenerative sources based solely on self-phase modulation and offset filtering. The regenerative similariton laser does not suffer from instabilities due to excessive nonlinearities and enables ultrashort pulse generation in a simple cavity configuration.

  7. Femtosecond Laser Filamentation

    CERN Document Server

    Chin, See Leang

    2010-01-01

    Femtosecond Laser Filamentation gives a comprehensive review of the physics of propagation of intense femtosecond laser pulses in optical media (principally air) and the applications and challenges of this new technique. This book presents the modern understanding of the physics of femtosecond laser pulse propagation, including unusual new effects such as the self-transformation of the pulse into a white light laser pulse, intensity clamping, the physics of multiple filamentation and competition, and how filaments’ ability to melt glass leads to wave guide writing. The potential applications of laser filamentation in atmospheric sensing and the generation of other electromagnetic pulses from the UV to the radio frequency are treated, together with possible future challenges in the excitation of super-excited states of molecules. Exciting new phenomena such as filament induced ultrafast birefringence and the excitation of molecular rotational wave packets and their multiple revivals in air (gases) will also ...

  8. Laser Beam Focus Analyser

    DEFF Research Database (Denmark)

    Nielsen, Peter Carøe; Hansen, Hans Nørgaard; Olsen, Flemming Ove

    2007-01-01

    The quantitative and qualitative description of laser beam characteristics is important for process implementation and optimisation. In particular, a need for quantitative characterisation of beam diameter was identified when using fibre lasers for micro manufacturing. Here the beam diameter limits...... the obtainable features in direct laser machining as well as heat affected zones in welding processes. This paper describes the development of a measuring unit capable of analysing beam shape and diameter of lasers to be used in manufacturing processes. The analyser is based on the principle of a rotating...... mechanical wire being swept through the laser beam at varying Z-heights. The reflected signal is analysed and the resulting beam profile determined. The development comprised the design of a flexible fixture capable of providing both rotation and Z-axis movement, control software including data capture...

  9. Laser controlled flame stabilization

    Science.gov (United States)

    Early, James W.; Thomas, Matthew E.

    2001-01-01

    A method and apparatus is provided for initiating and stabilizing fuel combustion in applications such as gas turbine electrical power generating engines and jet turbine engines where it is desired to burn lean fuel/air mixtures which produce lower amounts of NO.sub.x. A laser induced spark is propagated at a distance from the fuel nozzle with the laser ignitor being remotely located from the high temperature environment of the combustion chamber. A laser initiating spark generated by focusing high peak power laser light to a sufficiently tight laser spot within the fuel to cause the ionization of air and fuel into a plasma is unobtrusive to the flow dynamics of the combustion chamber of a fuel injector, thereby facilitating whatever advantage can be taken of flow dynamics in the design of the fuel injector.

  10. Auricular Acupuncture with Laser

    Science.gov (United States)

    Bahr, Frank

    2013-01-01

    Auricular acupuncture is a method which has been successfully used in various fields of medicine especially in the treatment of pain relief. The introduction of lasers especially low-level lasers into medicine brought besides the already existing stimulation with needles and electricity an additional technique to auricular acupuncture. This literature research looks at the historical background, the development and the anatomical and neurological aspects of auricular acupuncture in general and auricular laser acupuncture in detail. Preliminary scientific findings on auricular acupuncture with laser have been described in detail and discussed critically in this review article. The results of the studies have shown evidence of the effect of auricular laser acupuncture. However, a comparison of these studies was impossible due to their different study designs. The most important technical as well as study parameters were described in detail in order to give more sufficient evidence and to improve the quality of future studies. PMID:23935695

  11. NASA Space Laser Technology

    Science.gov (United States)

    Krainak, Michael A.

    2015-01-01

    Over the next two decades, the number of space based laser missions for mapping, spectroscopy, remote sensing and other scientific investigations will increase several fold. The demand for high wall-plug efficiency, low noise, narrow linewidth laser systems to meet different systems requirements that can reliably operate over the life of a mission will be high. The general trends will be for spatial quality very close to the diffraction limit, improved spectral performance, increased wall-plug efficiency and multi-beam processing. Improved spectral performance will include narrower spectral width (very near the transform limit), increased wavelength stability and or tuning (depending on application) and lasers reaching a wider range of wavelengths stretching into the mid-infrared and the near ultraviolet. We are actively developing high efficiency laser transmitter and high-sensitivity laser receiver systems that are suitable for spaceborne applications.

  12. Teradiode's high brightness semiconductor lasers

    Science.gov (United States)

    Huang, Robin K.; Chann, Bien; Burgess, James; Lochman, Bryan; Zhou, Wang; Cruz, Mike; Cook, Rob; Dugmore, Dan; Shattuck, Jeff; Tayebati, Parviz

    2016-03-01

    TeraDiode is manufacturing multi-kW-class ultra-high brightness fiber-coupled direct diode lasers for industrial applications. A fiber-coupled direct diode laser with a power level of 4,680 W from a 100 μm core diameter, world-record brightness levels for direct diode lasers. The fiber-coupled output corresponds to a Beam Parameter Product (BPP) of 3.5 mm-mrad and is the lowest BPP multi-kW-class direct diode laser yet reported. This laser is suitable for industrial materials processing applications, including sheet metal cutting and welding. This 4-kW fiber-coupled direct diode laser has comparable brightness to that of industrial fiber lasers and CO2 lasers, and is over 10x brighter than state-of-the-art direct diode lasers. We have also demonstrated novel high peak power lasers and high brightness Mid-Infrared Lasers.

  13. Laser-diode pumped Nd:YAG lasers; Laser diode reiki Nd:YAG lasear

    Energy Technology Data Exchange (ETDEWEB)

    Yuasa, H.; Akiyama, Y.; Nakayama, M. [Toshiba Corp., Tokyo (Japan)

    2000-04-01

    Laser-diode pumped Nd:YAG lasers are expected to be applied to laser processing fields such as welding, cutting, drilling, and marking due to their potential for high efficiency and compactness. We are designing and developing laser-diode pumped Nd:YAG lasers using numerical analysis simulation techniques such as ray tracing and thermal analysis. We have succeeded in achieving a laser power of more than 3 kW with 20% efficiency, which is the best ever obtained. In addition, we have developed a laser-diode pumped green laser by second harmonic generation, for precision machining on silicon wafers. (author)

  14. Laser autodyne angioscopy

    Science.gov (United States)

    Gordov, Eugeni P.; Makogon, Michail M.; Pekarskii, Vikentii V.; Shipulin, Vladimir M.

    1994-07-01

    A novel approach to imagination of inner surface of arteria during performing laser and balloon angioplasty is suggested. To this end the laser light was transmitted via fiber to the zone of interest and radiation diffused by the walls of the vessel was adopted by receiver. Known technique to determine of contours of an object by measuring the time of the laser pulse propagation is unusable due to the small geometrical scales. Using the CW laser and feeding a portion of the backscattered signal power into the laser cavity (this kind of device was referred to as laser autodyne coherent receiver), the authors have been able to measure the object contour with spatial resolution of up to 2 microns. Such resolution and high sensitivity inherent to this technique should allows one to detect early in the development of the atherosclerosis. To obtain the 3D image of the vessel inside surface we offer two methods. In the first case the vessel side is scanned by moving the end of light quid. In the second one multimode laser is used and the image is drawing by scanning the transverse modes of this laser. The vessel side and atherosclerotic plaques have the different reflectivity spectrum and this fact can be used to increase the image contrast. The correct selection of the laser wavelength makes possible to work into the vessel with circulation of the blood. The calculation of laser autodyne intrascope performance and tentative experimental results are presented in this report. The advantages of this method for the angiography are in speed and adequately of control during performing angioplasty.

  15. Risk Factors and Prevention

    Science.gov (United States)

    ... Factors & Prevention Back to Patient Resources Risk Factors & Prevention Even people who look healthy and free of ... as possible. Share: The Normal Heart Risk Factors & Prevention Heart Diseases & Disorders Substances & Heart Rhythm Disorders Symptoms & ...

  16. Prevent Back Pain

    Science.gov (United States)

    ... Prevent Back Pain Print This Topic En español Prevent Back Pain Browse Sections The Basics Overview Am ... at Risk? 3 of 5 sections Take Action: Prevent Injuries Focus on good posture. Good posture can ...

  17. Prevent Bite Wounds

    Science.gov (United States)

    ... Issues Listen Español Text Size Email Print Share Prevent Bite Wounds Page Content Article Body Each year, ... bite Swollen glands that occur above the bite Prevention of Bites and Infections To prevent bites and ...

  18. Stomach (Gastric) Cancer Prevention

    Science.gov (United States)

    ... Stomach Cancer Prevention Stomach Cancer Screening Research Stomach (Gastric) Cancer Prevention (PDQ®)–Patient Version What is prevention? Go ... has stayed about the same since 2005. Stomach (gastric) cancer is a disease in which malignant (cancer) cells ...

  19. Comparative shock wave analysis during corneal ablation with an excimer laser, picosecond laser, and femtosecond laser

    Science.gov (United States)

    Krueger, Ronald R.; Juhasz, Tibor

    1995-05-01

    With the event of topographic steep central islands following excimer laser surgery and the potential damage to the corneal endothelium, shock waves are playing an increasingly important role in laser refractive surgery. With this in mind, we performed a comparative shock wave analysis in corneal tissue using an excimer laser, picosecond laser, and femtosecond laser. We used a Lambda Physik excimer laser at 308 nm wavelength, a Nd:YLF picosecond laser at 1053 nm wavelength and a synchronously pumped linear cavity femtosecond laser at 630 nm wavelength. The pulse widths of the corresponding lasers were 8 ns, 18 ps, 150 fs, respectively. The energy density of irradiation was 2.5 to 8 times the threshold level being 2 J/cm2 (excimer laser), 86 J/cm2 (picosecond laser) and 10.3 J/cm2 (femtosecond laser). Shock wave dynamics were analyzed using time-resolved photography on a nanosecond time scale using the picosecond laser in corneal tissue, water and air. Shock wave dynamics using the femtosecond laser were studied in water only while the excimer laser induced shock wave during corneal ablation was studied in air only. We found the dynamics of shock waves to be similar in water and corneal tissue indicating that water is a good model to investigate shock wave effects in the cornea. The magnitude of the shock wave velocity and pressure decays over time to that of a sound wave. The distance over which it decays is 3 mm in air with the excimer laser and 600 - 700 micrometers in air with the picosecond laser. In water, the picosecond laser shock wave decays over a distance of 150 micrometers compared to the femtosecond laser shock wave which decays over a distance of 30 micrometers . Overall the excimer laser shock wave propagates 5 times further than that of the picosecond laser and the picosecond laser shock wave propagates 5 times further than that of the femtosecond laser. In this preliminary comparison, the time and distance for shock wave decay appears to be directly

  20. Direct Laser Acceleration in Laser Wakefield Accelerators

    Science.gov (United States)

    Shaw, J. L.; Froula, D. H.; Marsh, K. A.; Joshi, C.; Lemos, N.

    2017-10-01

    The direct laser acceleration (DLA) of electrons in a laser wakefield accelerator (LWFA) has been investigated. We show that when there is a significant overlap between the drive laser and the trapped electrons in a LWFA cavity, the accelerating electrons can gain energy from the DLA mechanism in addition to LWFA. The properties of the electron beams produced in a LWFA, where the electrons are injected by ionization injection, have been investigated using particle-in-cell (PIC) code simulations. Particle tracking was used to demonstrate the presence of DLA in LWFA. Further PIC simulations comparing LWFA with and without DLA show that the presence of DLA can lead to electron beams that have maximum energies that exceed the estimates given by the theory for the ideal blowout regime. The magnitude of the contribution of DLA to the energy gained by the electron was found to be on the order of the LWFA contribution. The presence of DLA in a LWFA can also lead to enhanced betatron oscillation amplitudes and increased divergence in the direction of the laser polarization. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  1. History and principle of lasers; Histoire et principe des lasers

    Energy Technology Data Exchange (ETDEWEB)

    Townes, Ch.H. [Universite de Californie, Berkeley (United States); Schwob, C. [Institut de Nanosciences de Paris, UPMC/CNRS, 75 - Paris (France); Julien, L. [Lab. Kastler Brossel ENS/UPMC/CNRS, 75 - Paris (France); Forget, S. [Lab. de Physique des Lasers, Paris-13 Univ., 93 - Villetaneuse (France); Robert-Philip, I. [Lab. de Photonique et de anostructures, CNRS, 91 - Marcoussis (France); Balcou, Ph. [Centre des lasers Intenses et Applications, Bordeaux-1 Univ., 33 - Talence (France)

    2010-10-15

    This document gathers 3 short articles: in the first one, C.H. Townes, the inventor of the laser, presents the genesis of the laser, while the principle of the laser is described in the second and the different types of lasers are reviewed in the third. The most important technological progress is expected in ultra-intense lasers that will be used in inertial fusion in gigantic facilities

  2. [Lasers in dentistry 1. What is special about lasers?].

    Science.gov (United States)

    ten Bosch, J J

    2002-03-01

    Diagnosis and treatment with lasers is becoming widely spread in dentistry. This article is an introduction to a series of articles that deal with the many dental applications of lasers. The article contains a summary of presently used lasers. It also describes the pertinent features of laser radiation: parallelism of the beam and narrow line shape in the spectrum of electromagnetic radiation. Finally, it summarizes the relevant processes of interaction of laser radiation with tissue: scattering, absorption, fluorescence and frequency-doubling.

  3. 1982 laser program annual report

    Energy Technology Data Exchange (ETDEWEB)

    Hendricks, C.D.; Grow, G.R. (eds.)

    1983-08-01

    This annual report covers the following eight sections: (1) laser program review, (2) laser systems and operation, (3) target design, (4) target fabrication, (5) fusion experiments program, (6) Zeus laser project, (7) laser research and development, and (8) energy applications. (MOW)

  4. Femtosecond petawatt laser

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Tae Moon; Lee, Jongmin [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology (Korea, Republic of)

    2014-04-15

    The high-power femtosecond laser has now become an excellent scientific tool for the study of not only relativistic laser-matter interactions but also scientific applications. The high-power femtosecond laser depends on the Kerr-lens modelocking (KLM) and chirped-pulse amplification (CPA) technique. An all-Ti:sapphire-based 30-fs PW CPA laser, which is called the PULSER (Petawatt Ultrashort Laser System for Extreme Science Research) has been recently constructed and is being used for accelerating the charged particles (electrons and protons) and generating ultrashort high-energy photon (X-ray and γ-ray) sources. In this review, the world-wide PW-level femtosecond laser systems are first summarized, the output performances of the PULSER-I and II are described, and the future upgrade plan of the PULSER to the multi-PW level is also discussed. Then, several experimental results on particle (electron and proton) acceleration and X-ray generation in the intensity range of mid-10{sup 18} W/cm{sup 2} to mid-10{sup 20} W/cm{sup 2} are described. Experimental demonstrations for the newly proposed phenomena and the understanding of physical mechanisms in relativistic and ultrarelativistic regimes are highly expected as increasing the laser peak intensity up to over 10{sup 22} W/cm{sup 2} ∝10{sup 23} W/cm{sup 2}. (copyright 2014 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Laser scar revision.

    Science.gov (United States)

    Lupton, Jason R; Alster, Tina S

    2002-01-01

    A variety of lasers can be used to treat scars and striae effectively. It is of paramount importance that the type of scar be properly classified on initial examination so that the most appropriate method of treatment can be chosen. Classification also allows the laser surgeon to discuss with the patient the anticipated response to treatment. The 585-nm pulsed dye laser (PDL) is the most appropriate system for treating hypertrophic scars, keloids, erythematous scars, and striae. The PDL carries a low risk of side effects and complications when operated at appropriate treatment parameters and time intervals. Atrophic scars are best treated with ablative CO2 and Er:YAG lasers; however, proliferative keloids and hypertrophic scars should not be vaporized because of the high risk of scar recurrence or progression. The appropriate choice and use of lasers can significantly improve most scars. As research in laser-skin interaction continues, further refinements in laser technology coupled with the addition of alternate treatment procedures will allow improved clinical efficacy and predictability.

  6. Novel laser ion sources

    CERN Document Server

    Fournier, P; Kugler, H; Lisi, N; Scrivens, R; Rodríguez, F V; Düsterer, S; Sauerbrey, R; Schillinger, H; Theobald, W; Veisz, L; Tisch, J W G; Smith, R A

    2000-01-01

    Development in the field of high-power laser systems with repetition rates of several Hz and energies of few joules is highly active and opening, giving new possibilities for the design of laser ions sources. Preliminary investigations on the use of four different laser and target configurations are presented: (1) A small CO/sub 2/ laser (100 mJ, 10.6 mu m) focused onto a polyethylene target to produce C ions at 1 Hz repetition rate (CERN). (2) An excimer XeCl laser (6 J, 308 nm) focused onto solid targets (Frascati). (3) A femtosecond Ti: sapphire laser (250 mJ, 800 nm) directed onto a solid targets (Jena). (4) A picosecond Nd: yttrium-aluminum-garnet (0.3 J, 532 nm) focused into a dense medium of atomic clusters and onto solid targets (London). The preliminary experimental results and the most promising schemes will be discussed with respect to the scaling of the production of high numbers of highly charged ions. Different lasers are compared in terms of current density at 1 m distance for each charge state...

  7. Ultra-intense lasers

    CERN Document Server

    Mourou, G

    2002-01-01

    This article reviews the applications of ultra-intense lasers in domains like particle acceleration, gamma-gamma collisions, cancer diagnostic, eye surgery and inertial fusion. The main characteristic of such lasers is to deliver impulses carrying the same amount of energy as did previous generations of lasers but in a far shorter time which increases their power dramatically. Typically an ultra-intense laser releases 1 joule through an impulse that lasts 100 femtoseconds which means a power of 10 sup 1 sup 3 Watt. The method of the amplification of impulses through frequency shift (CPA) has allowed power lasers to reach power levels that were beyond the technological limits of amplifying equipment (10 sup 9 W). The powerful electrical field of a femtosecond laser impulse make electrons oscillate with speeds nearing the speed of light while its magnetic field accelerates them in the perpendicular direction of the oscillation plane. Ultra-intense lasers generate electric fields from 10 sup 1 sup 2 to 10 sup 1 ...

  8. Color Laser Microscope

    Science.gov (United States)

    Awamura, D.; Ode, T.; Yonezawa, M.

    1987-04-01

    A color laser microscope utilizing a new color laser imaging system has been developed for the visual inspection of semiconductors. The light source, produced by three lasers (Red; He-Ne, Green; Ar, Blue; He-Cd), is deflected horizontally by an AOD (Acoustic Optical Deflector) and vertically by a vibration mirror. The laser beam is focused in a small spot which is scanned over the sample at high speed. The light reflected back from the sample is reformed to contain linear information by returning to the original vibration mirror. The linear light is guided to the CCD image sensor where it is converted into a video signal. Individual CCD image sensors are used for each of the three R, G, or B color image signals. The confocal optical system with its laser light source yields a color TV monitor image with no flaring and a much sharper resolution than that of the conventional optical microscope. The AOD makes possible a high speed laser scan and a NTSC or PAL TV video signal is produced in real time without any video memory. Since the light source is composed of R, G, and B laser beams, color separation superior to that of white light illumination is achieved. Because of the photometric linearity of the image detector, the R, G, and B outputs of the system are most suitably used for hue analysis. The CCD linear image sensors in the optical system produce no geometrical distortion, and good color registration is available principally. The output signal can be used for high accuracy line width measuring. The many features of the color laser microscope make it ideally suited for the visual inspection of semiconductor processing. A number of these systems have already been installed in such a capacity. The Color Laser Microscope can also be a very useful tool for the fields of material engineering and biotechnology.

  9. Dye laser principles with applications

    CERN Document Server

    Duarte, Frank J; Liao, Peter F; Kelley, Paul

    1990-01-01

    A tutorial introduction to the field of dye lasers, Dye Laser Principles also serves as an up-to-date overview for those using dye lasers as research and industrial tools. A number of the issues discussed in this book are pertinent not only to dye lasers but also to lasers in general. Most of the chapters in the book contain problem sets that expand on the material covered in the chapter.Key Features* Dye lasers are among the most versatile and successful laser sources currently available in use Offering both pulsed and continuous-wave operation and tunable from the near ultraviole

  10. Temperature measurements during laser skin welding

    Science.gov (United States)

    Fried, Nathaniel M.; Choi, Bernard; Welch, Ashley J.; Walsh, Joseph T., Jr.

    1999-06-01

    A thermal camera was used to measure surface temperatures during laser skin welding to provide feedback for optimization of the laser parameters. Two-cm-long, full- thickness incisions were made in guinea pig skin. India ink was used as an absorber. Continuous-wave, 1.06-μm, Nd:YAG laser radiation was scanned over the incisions, producing a pulse duration of approximately 100 ms. Cooling durations between scans of 1.6, 4.0, and 8.0 s were studied with total operation times of 3, 5, and 10 min, respectively. A laser spot diameter of 5 mm was used with the power constant at 10 W. Thermal images were obtained at 30 frames per second with a thermal camera detecting 3.5 micrometers radiation. Surface temperatures were recorded at 0, 1, and 6 mm from the center line of the incision. Cooling durations between scans of 1.6 s and 4.0 s in vitro resulted in temperatures at the weld site remaining above ~65°C for prolonged periods of time. Cooling durations between scans as long as 8.0 s were sufficient both in vitro and in vivo to prevent a significant rise in baseline temperatures at the weld site over time.

  11. Color speckle in laser displays

    Science.gov (United States)

    Kuroda, Kazuo

    2015-07-01

    At the beginning of this century, lighting technology has been shifted from discharge lamps, fluorescent lamps and electric bulbs to solid-state lighting. Current solid-state lighting is based on the light emitting diodes (LED) technology, but the laser lighting technology is developing rapidly, such as, laser cinema projectors, laser TVs, laser head-up displays, laser head mounted displays, and laser headlamps for motor vehicles. One of the main issues of laser displays is the reduction of speckle noise1). For the monochromatic laser light, speckle is random interference pattern on the image plane (retina for human observer). For laser displays, RGB (red-green-blue) lasers form speckle patterns independently, which results in random distribution of chromaticity, called color speckle2).

  12. Organic solid-state lasers

    CERN Document Server

    Forget, Sébastien

    2013-01-01

    Organic lasers are broadly tunable coherent sources, potentially compact, convenient and manufactured at low-costs. Appeared in the mid 60’s as solid-state alternatives for liquid dye lasers, they recently gained a new dimension after the demonstration of organic semiconductor lasers in the 90's. More recently, new perspectives appeared at the nanoscale, with organic polariton and surface plasmon lasers. After a brief reminder to laser physics, a first chapter exposes what makes organic solid-state organic lasers specific. The laser architectures used in organic lasers are then reviewed, with a state-of-the-art review of the performances of devices with regard to output power, threshold, lifetime, beam quality etc. A survey of the recent trends in the field is given, highlighting the latest developments with a special focus on the challenges remaining for achieving direct electrical pumping of organic semiconductor lasers. A last chapter covers the applications of organic solid-state lasers.

  13. Physics of semiconductor laser devices

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, G.H.B.

    1980-01-01

    Aspects of laser design and development are considered along with semiconductor materials for lasers, problems of device fabrication, crystal growth, the degradation of lasers, and the integration of semiconductor lasers with other optical components. A description is presented of light emission processes and laser action in semiconductors, taking into account electronic radiative transitions, the relation between emission and absorption processes, transition probabilities, the density of electron states in the highly doped semiconductor, carrier recombination and spontaneous emission, the gain/current relation, light-current characteristics, optical modes, and the evolution of mode spectrum and intensity with current. Attention is given to laser heterostructures and the properties of heterojunctions, optical waveguides, the performance of heterostructure lasers, stripe geometry lasers, and the dynamic response of lasers. Lasers with distributed feedback and Bragg reflectors are also discussed.

  14. Monoenergetic laser wakefield acceleration

    Directory of Open Access Journals (Sweden)

    N. E. Andreev

    2000-02-01

    Full Text Available Three dimensional test particle simulations are applied to optimization of the plasma-channeled laser wakefield accelerator (LWFA operating in a weakly nonlinear regime. Electron beam energy spread, emittance, and luminosity depend upon the proportion of the electron bunch size to the plasma wavelength. This proportion tends to improve with the laser wavelength increase. We simulate a prospective two-stage ∼1GeV LWFA with controlled energy spread and emittance. The input parameters correspond to realistic capabilities of the BNL Accelerator Test Facility that features a picosecond-terawatt CO_{2} laser and a high-brightness electron gun.

  15. Lasers In Dental Diagnosis

    Science.gov (United States)

    Everse, K. E.; Sinor, T. W.; Menzel, E. R.

    1987-01-01

    We have investigated the potential of lasers for real time in situ dental diagnosis via transillumination of teeth and gums and via fluorescence. Not surprisingly, absorption and/or scattering of light by teeth was found to be insensitive to light color. However, monochromatic transillumination revealed detail better than white light. Transillumination of gums was best performed with orange-red light because of tissue absorption. Illumination of oral structures by 488 nm Ar-laser light was effective in revealing diagnosis detail by fluorescence. Incipient caries and fine tooth fracture lines that are generally not revealed by radiography were observable by laser.

  16. Laser undulator radiation

    CERN Document Server

    Kawamura, Y; Ruschin, S; Tanabé, T; Toyoda, K

    2000-01-01

    Various characteristics such as the number of photons, the wavelength, and the solid angle of the laser undulator radiation have been measured quantitatively. It was performed in the visible wavelength region using the interaction between a high-power pulsed CO sub 2 laser and a high-quality electron beam having an energy of 0.65-0.85 MeV. The experimental results were in good agreement with the theoretical calculations. A criterion to determine the limitation to the number of periods of the laser undulator was also proposed.

  17. Optimising laser tattoo removal

    Directory of Open Access Journals (Sweden)

    Kabir Sardana

    2015-01-01

    Full Text Available Lasers are the standard modality for tattoo removal. Though there are various factors that determine the results, we have divided them into three logical headings, laser dependant factors such as type of laser and beam modifications, tattoo dependent factors like size and depth, colour of pigment and lastly host dependent factors, which includes primarily the presence of a robust immune response. Modifications in the existing techniques may help in better clinical outcome with minimal risk of complications. This article provides an insight into some of these techniques along with a detailed account of the factors involved in tattoo removal.

  18. Optimising Laser Tattoo Removal

    Science.gov (United States)

    Sardana, Kabir; Ranjan, Rashmi; Ghunawat, Sneha

    2015-01-01

    Lasers are the standard modality for tattoo removal. Though there are various factors that determine the results, we have divided them into three logical headings, laser dependant factors such as type of laser and beam modifications, tattoo dependent factors like size and depth, colour of pigment and lastly host dependent factors, which includes primarily the presence of a robust immune response. Modifications in the existing techniques may help in better clinical outcome with minimal risk of complications. This article provides an insight into some of these techniques along with a detailed account of the factors involved in tattoo removal. PMID:25949018

  19. Laser propulsion: a review

    CSIR Research Space (South Africa)

    Michaelis, MM

    2006-07-01

    Full Text Available is that the Crookes radiometer rotates due to photon rather than gas pressure. In fact, the very first pure photon pendulum experiment was carried out by American laser propulsion enthusiasts Myrabo, Knowles, Bagford, Siebert and Harris.31 The photon pressure... is minute: the photon force on a 10-cm2 target illuminated by a 9-kW CO2 laser is found from: hence the need for an ultra-delicate pendulum equipment, as well as for a high-power laser source! In marked contrast to the Myrabo experiment...

  20. Laser in manufacturing

    CERN Document Server

    Davim, J Paulo

    2013-01-01

    Generally a laser (light amplification by stimulated emission of radiation) is defined as "a device which uses a quantum mechanical effect, stimulated emission, to generate a coherent beam of light from a lasing medium of controlled purity, size, and shape". Laser material processing represents a great number of methods, which are rapidly growing in current and different industrial applications as new alternatives to traditional manufacturing processes. Nowadays, the use of lasers in manufacturing is an emerging area with a wide variety of applications, for example, in electronics, molds an

  1. Ultrashort Laser Pulse Phenomena

    CERN Document Server

    Diels, Jean-Claude

    2006-01-01

    Ultrashort Laser Pulse Phenomena, 2e serves as an introduction to the phenomena of ultra short laser pulses and describes how this technology can be used to examine problems in areas such as electromagnetism, optics, and quantum mechanics. Ultrashort Laser Pulse Phenomena combines theoretical backgrounds and experimental techniques and will serve as a manual on designing and constructing femtosecond (""faster than electronics"") systems or experiments from scratch. Beyond the simple optical system, the various sources of ultrashort pulses are presented, again with emphasis on the basic

  2. Assisting Gas Optimization in CO2 Laser Welding

    DEFF Research Database (Denmark)

    Gong, Hui; Olsen, Flemming Ove

    1996-01-01

    High quality laser welding is achieved under the condition of optimizing all process parameters. Assisting gas plays an important role for sound welds. In the conventional welding process assisting gas is used as a shielding gas to prevent that the weld seam oxidates. In the laser welding process...... assisting gas is also needed to control the laser induced plasma.Assisting gas is one of the most important parameters in the laser welding process. It is responsible for obtaining a quality weld which is characterized by deep penetration, no interior imperfections, i.e. porosity, no crack, homogeneous seam...... surface, etc. In this work a specially designed flexible off-axis nozzle capable of adjusting the angle of the nozzle, the diameter of the nozzle, and the distance between the nozzle end and the welding zone is tested. In addition to the nozzle parameters three gases, Nitrogen, Argon, and Helium...

  3. Recent developments in retinal lasers and delivery systems

    Directory of Open Access Journals (Sweden)

    Naresh Kumar Yadav

    2014-01-01

    Full Text Available Photocoagulation is the standard of care for several ocular disorders and in particular retinal conditions. Technology has offered us newer lasing mediums, wavelengths and delivery systems. Pattern scan laser in proliferative diabetic retinopathy and diabetic macular edema allows laser treatment that is less time consuming and less painful. Now, it is possible to deliver a subthreshold micropulse laser that is above the threshold of biochemical effect but below the threshold of a visible, destructive lesion thereby preventing collateral damage. The advent of solid-state diode yellow laser allows us to treat closer to the fovea, is more effective for vascular structures and offers a more uniform effect in patients with light or irregular fundus pigmentation. Newer retinal photocoagulation options along with their advantages is discussed in this review.

  4. Excision of oral mucocele by different wavelength lasers

    Directory of Open Access Journals (Sweden)

    Umberto Romeo

    2013-01-01

    Full Text Available Background: Mucocele is a common benign neoplasm of oral soft tissues and the most common after fibroma. It generally occurs in the lower lip and its treatment includes excision of cyst and the responsible salivary gland, in order to prevent recurrences. Aims: To evaluate the capability of three different lasers in performing the excision of labial mucocele with two different techniques. Materials and Methods: In the presented cases, excision was performed using two different techniques (circumferential incision technique and mucosal preservation technique and three different laser wavelengths (Er,Cr:YSGG 2780 nm, diode 808 nm, and KTP 532 nm. Results: All the tested lasers, regardless of wavelength, showed many advantages (bloodless surgical field, no postoperative pain, relative speed, and easy execution. The most useful surgical technique depends on clinical features of the lesion. Conclusion: Tested lasers, with both techniques, are helpful in the management of labial mucocele.

  5. Laser applications in neurosurgery

    Science.gov (United States)

    Cerullo, Leonard J.

    1985-09-01

    The "false start" of the laser in neurosurgery should not be misconstrued as a denial of the inherent advantages of precision and gentleness in dealing with neural tissue. Rather, early investigators were frustrated by unrealistic expectations, cumbersome equipment, and a general ignorance of microtechnique. By the early 70s, microneurosurgery was well established, surgical laser equipment for free hand and microlinked application had been developed, and a more realistic view of the limitations of the laser had been established. Consequently, the late 70s really heralded the renaissance of the laser in neurosurgery. Since then, there has been an overwhelming acceptance of the tool in a variety of clinical situations, broadly categorized in five groups. 1)|Perhaps the most generally accepted area is in the removal of extra-axial tumors of the brain and spinal cord. These tumors, benign by histology but treacherous by location, do not present until a significant amount of neurological compensation has already occurred. The application of additional trauma to the neural tissue, whether by further tumor growth or surgical manipulation, frequently results in irreversible damage. Here, the ability of the laser to vaporize tissue, in a fairly hemostatic fashion, without mechanical or thermal damage to sensitive surrounding tissues, is essential. 2)|The ability to incise delicate neural tissue with minimal spread of thermal destruction to adjacent functioning tissue makes the laser the ideal instrument when tumors deep under the surface are encountered in the brain or spinal cord. Thus, the second group of applications is in the transgression of normal neural structures to arrive at deeper pathological tissue. 3)|The third area of benefit for the laser in neurosurgery has been in the performance of neuroablative procedures, calling for deliberate destruction of functioning neural tissue in a controlled fashion. Again, the precision and shape confinement of the destructive

  6. Crack formation and prevention in colloidal drops

    Science.gov (United States)

    Kim, Jin Young; Cho, Kun; Ryu, Seul-A.; Kim, So Youn; Weon, Byung Mook

    2015-08-01

    Crack formation is a frequent result of residual stress release from colloidal films made by the evaporation of colloidal droplets containing nanoparticles. Crack prevention is a significant task in industrial applications such as painting and inkjet printing with colloidal nanoparticles. Here, we illustrate how colloidal drops evaporate and how crack generation is dependent on the particle size and initial volume fraction, through direct visualization of the individual colloids with confocal laser microscopy. To prevent crack formation, we suggest use of a versatile method to control the colloid-polymer interactions by mixing a nonadsorbing polymer with the colloidal suspension, which is known to drive gelation of the particles with short-range attraction. Gelation-driven crack prevention is a feasible and simple method to obtain crack-free, uniform coatings through drying-mediated assembly of colloidal nanoparticles.

  7. Crack formation and prevention in colloidal drops.

    Science.gov (United States)

    Kim, Jin Young; Cho, Kun; Ryu, Seul-A; Kim, So Youn; Weon, Byung Mook

    2015-08-17

    Crack formation is a frequent result of residual stress release from colloidal films made by the evaporation of colloidal droplets containing nanoparticles. Crack prevention is a significant task in industrial applications such as painting and inkjet printing with colloidal nanoparticles. Here, we illustrate how colloidal drops evaporate and how crack generation is dependent on the particle size and initial volume fraction, through direct visualization of the individual colloids with confocal laser microscopy. To prevent crack formation, we suggest use of a versatile method to control the colloid-polymer interactions by mixing a nonadsorbing polymer with the colloidal suspension, which is known to drive gelation of the particles with short-range attraction. Gelation-driven crack prevention is a feasible and simple method to obtain crack-free, uniform coatings through drying-mediated assembly of colloidal nanoparticles.

  8. Gas ion laser construction for electrically isolating the pressure gauge thereof

    Science.gov (United States)

    Wood, C. E.; Witte, R. S. (Inventor)

    1975-01-01

    The valve and the pressure gauge of a gas ion laser were electrically insulated from the laser discharge path by connecting them in series with the cathode of the laser. The laser cathode can be grounded and preferably is a cold cathode although a hot cathode may be used instead. The cold cathode was provided with a central aperture to which was connected both the pressure gauge and the gas pressure reservoir through the valve. This will effectively prevent electric discharges from passing either to the pressure gauge or the valve which would otherwise destroy the pressure gauge.

  9. Pyrometry applications in laser machining

    Science.gov (United States)

    Smurov, Igor

    2001-01-01

    Special techniques of non-contact optical diagnostics under actual industrial conditions is required for accurate temperature monitoring and control in a wide range of laser applications. The set of pyrometers was developed and applied for surface temperature monitoring in pulsed periodic Nd:YAG laser welding and surface treatment, deep penetration welding by CO2 and Nd:YAG lasers, and electron beam; laser assisted machining; laser cladding, etc.

  10. Laser forming and welding processes

    CERN Document Server

    Yilbas, Bekir Sami; Shuja, Shahzada Zaman

    2013-01-01

    This book introduces model studies and experimental results associated with laser forming and welding such as laser induced bending, welding of sheet metals, and related practical applications. The book provides insight into the physical processes involved with laser forming and welding. The analytical study covers the formulation of laser induced bending while the model study demonstrates the simulation of bending and welding processes using the finite element method. Analytical and numerical solutions for laser forming and welding problems are provided.

  11. Laser-Induced Choroidal Neovascularizations: Clinical Study of 3 Cases

    Directory of Open Access Journals (Sweden)

    Wipada Laovirojjanakul

    2017-08-01

    Full Text Available Background: We report 3 patients with laser-induced choroidal neovascularization (CNV. Method: Retrospective, observational case series. Medical charts and photographs were reviewed. Results: Two patients with central serous chorioretinopathy who developed iatrogenic CNV after focal laser photocoagulation were treated with intravitreal ranibizumab injections. One patient with CNV secondary to thermal laser photocoagulation for diabetic macular edema was treated with photodynamic therapy (PDT. Visual improvement has been demonstrated in the patients treated with intravitreal ranibizumab injections, and their successful visual outcome was stable for more than 2 years. Stable visual acuity was also observed in the patient treated with PDT, no visual improvement was observed possibly due to the macular scar and macular ischemia. No systemic or ocular complications were detected among the 3 cases. Conclusion: To prevent a laser-induced CNV, it is critical to avoid heavy small-spot laser burns and repeated application. Patients should be monitored carefully for CNV after laser treatment. In our cases, PDT and intravitreal ranibizumab injections were effective for the treatment of laser-induced CNV.

  12. Improving executive function using transcranial infrared laser stimulation.

    Science.gov (United States)

    Blanco, Nathaniel J; Maddox, W Todd; Gonzalez-Lima, Francisco

    2017-03-01

    Transcranial infrared laser stimulation is a new non-invasive form of low-level light therapy that may have a wide range of neuropsychological applications. It entails using low-power and high-energy-density infrared light from lasers to increase metabolic energy. Preclinical work showed that this intervention can increase cortical metabolic energy, thereby improving frontal cortex-based memory function in rats. Barrett and Gonzalez-Lima (2013, Neuroscience, 230, 13) discovered that transcranial laser stimulation can enhance sustained attention and short-term memory in humans. We extend this line of work to executive function. Specifically, we ask whether transcranial laser stimulation enhances performance in the Wisconsin Card Sorting Task that is considered the gold standard of executive function and is compromised in normal ageing and a number of neuropsychological disorders. We used a laser of a specific wavelength (1,064 nm) that photostimulates cytochrome oxidase - the enzyme catalysing oxygen consumption for metabolic energy production. Increased cytochrome oxidase activity is considered the primary mechanism of action of this intervention. Participants who received laser treatment made fewer errors and showed improved set-shifting ability relative to placebo controls. These results suggest that transcranial laser stimulation improves executive function and may have exciting potential for treating or preventing deficits resulting from neuropsychological disorders or normal ageing. © 2015 The British Psychological Society.

  13. Laser surgery as a treatment for oral leukoplakia.

    Science.gov (United States)

    Ishii, J; Fujita, K; Komori, T

    2003-12-01

    Various treatment procedures for oral leukoplakia have been reported. However, after some treatments, oral leukoplakia show recurrence and/or malignant transformation, even following complete resection. Furthermore, patients with oral leukoplakia may develop new lesions in other oral cavity locations. Laser surgery for oral mucosal lesions has been reported to have many advantages, and it is widely used in the treatment of oral leukoplakia. In previous studies, recurrence and malignant transformation from the lesion have occasionally been observed following laser surgery. We reviewed the records of oral leukoplakia patients treated with laser surgery to assess its clinical usefulness. It has been reported that the rate of recurrence was 7.7-38.1%, while malignant transformation was 2.6-9% for oral leukoplakia treated with laser surgery. In the present study, there was 29.3% recurrence and 1.2% malignant transformation after laser surgery. This was similar to previous findings. This suggests that non-homogeneous leukoplakia on nonkeratinized epithelia, i.e. the tongue mucosa has a high risk for malignant transformation, so lesions should be excised after detecting abnormal epithelia using vital tissue staining. The wound healing process after laser surgery was satisfactory and no significant complications were observed. Management of oral leukoplakia prevents not only recurrence and malignant transformation, but also postoperative dysfunction: laser surgery is an excellent procedure that is able to overcome these problems.

  14. Lasers and intense pulsed light (IPL) association with cancerous lesions.

    Science.gov (United States)

    Ash, Caerwyn; Town, Godfrey; Whittall, Rebecca; Tooze, Louise; Phillips, Jaymie

    2017-11-01

    The development and use of light and lasers for medical and cosmetic procedures has increased exponentially over the past decade. This review article focuses on the incidence of reported cases of skin cancer post laser or IPL treatment. The existing evidence base of over 25 years of laser and IPL use to date has not raised any concerns regarding its long-term safety with only a few anecdotal cases of melanoma post treatment over two decades of use; therefore, there is no evidence to suggest that there is a credible cancer risk. Although laser and IPL technology has not been known to cause skin cancer, this does not mean that laser and IPL therapies are without long-term risks. Light therapies and lasers to treat existing lesions and CO2 laser resurfacing can be a preventative measure against BCC and SCC tumour formation by removing photo-damaged keratinocytes and encouraged re-epithelisation from stem cells located deeper in the epidermis. A review of the relevant literature has been performed to address the issue of long-term IPL safety, focussing on DNA damage, oxidative stress induction and the impact of adverse events.

  15. [Experimental and clinical experiences with bronchologic lasers].

    Science.gov (United States)

    Knoth, E; Wiesner, B; Dürschmied, H

    1987-01-01

    Bronchological application of lasers is based on differences of their biophysical effects, which were confirmed in experimental investigations. There were early reepithelizations and rapid healing after laser tracheotomy and lung resections without signs secondary stenoses by hypergranulation. Argon laser is of limited use in bronchology for HpD-coupled tumor fluorescence diagnostic. Nd-YAG-laser is the "classic" laser for palliative bronchial tumor therapy. Improvements of laser applications (laser thoracoscopy, perthoracic laser punction therapy) are new therapeutic laser methods.

  16. Fabrication of microchannels on PMMA using a low power CO2 laser

    Science.gov (United States)

    Imran, Muhammad; Rahman, Rosly A.; Ahmad, Mukhtar; Akhtar, Majid N.; Usman, Arslan; Sattar, Abdul

    2016-09-01

    This study presents a cheap and quick method for the formation of microchannels on poly methyl methacrylate (PMMA). A continuous wave CO2 laser with a wavelength of 10.6 μm was used to inscribe periodic ripple structures on a PMMA substrate. A direct writing technique was employed for micromachining. As PMMA is very sensitive to such laser irradiations, a slightly low power CO2 laser was effective in inscribing such periodic structures. The results show that smooth and fine ripple structures can be fabricated by controlling the input laser parameters and interaction time of the laser beam. This direct laser writing technique is promising enough to prevent us from using complex optical arrangements. Laser power was tested starting from the ablation threshold and was gradually increased, together with the variation in scanning speed of the xy-translational stage, to observe the effects on the target surface in terms of depth and width of trenches. It was observed that the depth of the trenches increases on increasing the laser power, and the bulge formation on the outer sides of the trenches was also studied. It was evident that the formation of bulges across the trenches is dependent on the scanning speed and input laser power. The results depict that a focused laser beam with optimized parameters, such as controlling the scanning speed and laser power, results in fine, regular and tidy periodic structures.

  17. Effect of low level laser (LLL) on cochlear and vestibular inner ear including tinnitus

    Science.gov (United States)

    Rhee, Chung-Ku; Lim, Eun-Seok; Kim, Young-Saeng; Chung, Yong-Won; Jung, Jae-Yun; Chung, Phil-Sang

    2006-02-01

    Objectives: 1. To investigate preventive effect of LLL on gentamicin-induced vestibular ototoxicity. 2. To evaluate the effectiveness of lower level laser (LLL) in the treatment of tinnitus. Methods: 1. Twenty guinea pigs were divided into control and laser groups. Vestibular ototoxicity was induced by intratympanic injection of gentamicin into left ear. LLL was irradiated into left ear canal of animals in laser group. Vestibular function of the animals was evaluated with vertical and off-vertical axis rotation testing. 2. Forty patients with tinnitus were treated with ginkgo biloba orally and randomly divided into control and laser groups. The 20 patients of laser group received 80.4 J/cm2 of 830 nm laser, 3 times per week for 4 weeks, via transmeatal irradiation. Tinnitus was evaluated by visual analogue scale (VAS) and tinnitus handicap inventory (THI). Results: 1. Preventive effect of LLL to gentamicin induced vestibular ototoxicity was demonstrated by preventing reduction of gain in slow harmonic acceleration test and modulation in the off-vertical axis rotation test. 2. Eleven of 20 laser group patients have shown significant improvement in VAS and THI compared to those of the control group. Conclusions: 1. LLL therapy may have preventive effect to vestibular ototoxicity. 2. LLL therapy in combination with ginkgo biloba seems to be worth trying on patients with tinnitus.

  18. Effect of pulse energy and density on laser peening of Inconel 600 without a protective coating

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Joung Soo; Choi, Jong Wan; Chung, Chinman [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Han, Weon JIn; Park, Kwang Soo [Doosan Heavy Industries and Construction Co., Ltd., Changwon (Korea, Republic of)

    2014-05-15

    In this study, a laser peening process without protective coating on an Inconel 600 plate is being developed for application to a BMI (bottom mounted instrument) J-weld and nozzle inner wall in a PWR reactor vessel to prevent PWSCC occurring in weld areas during operating nuclear power plants. To obtain the optimum peening conditions, laser peening was performed in water at different peening parameters to obtain the maximum compressive residual stress and depth on the Alloy 600 plate. From a study on laser peening without a protective surface coating, the effect of its process has been proved to be high enough to prevent Inconel 600 material for stress corrosion cracking. The effect of laser peening on susceptibility to stress corrosion cracking of Inconel 600 was confirmed by stress corrosion cracking tests; no stress corrosion cracking was occurred in a laser-peened specimen, while an un-peened specimen failed by cracking in a very short period of testing time.

  19. Multispot fiber laser welding

    DEFF Research Database (Denmark)

    Schutt Hansen, Klaus

    This dissertation presents work and results achieved in the field of multi beam fiber laser welding. The project has had a practical approach, in which simulations and modelling have been kept at a minimum. Different methods to produce spot patterns with high power single mode fiber lasers have...... been examined and evaluated. It is found that both diamond turned DOE’s in zinc sulphide and multilevel etched DOE’s (Diffractive Optical Elements) in fused silica have a good performance. Welding with multiple beams in a butt joint configuration has been tested. Results are presented, showing it has...... been possible to control the welding width in incremental steps by adding more beams in a row. The laser power was used to independently control the keyhole and consequently the depth of fusion. An example of inline repair of a laser weld in butt joint configuration was examined. Zinc powder was placed...

  20. Jupiter Laser Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Jupiter Laser Facility is an institutional user facility in the Physical and Life Sciences Directorate at LLNL. The facility is designed to provide a high degree...