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YAG
Terms modified by YAG Selected AbstractsLaser-induced crystal growth of nonlinear optical Ba3Ti3O6(BO3)2 on glass surfaceCRYSTAL RESEARCH AND TECHNOLOGY, Issue 12 2008T. Oikawa Abstract Nonlinear optical Ba3Ti3O6(BO3)2 crystals were patterned on the surface of CuO (1 mol%)-doped 40BaO-40TiO2 -20B2O3 glass by irradiations of continuous-wave Nd:YAG (wavelength: ,=1064 nm) and Yb:YVO4 (,=1080 nm) lasers. Laser energies absorbed by Cu2+ ions were transferred to the lattice system through a nonradiative relaxation process, consequently heating the glass and inducing local crystallizations. For the lines patterned by Yb:YVO4 laser irradiations with a power of 1 W and a scanning speed of 20 ,m/s, a c -axis orientation of Ba3Ti3O6(BO3)2 crystals along the laser scanning direction is proposed from measurements of X-ray diffraction analyses, polarized optical photographs, polarized micro-Raman scattering spectra, and azimuthal dependence of second harmonic generations. The laser-induced crystallization technique is found to be applied successfully for the spatially selective patterning of nonlinear optical Ba3Ti3O6(BO3)2 crystals in glass. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Influence of internal radiation on the heat transfer during growth of YAG single crystals by the Czochralski methodCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2003Z. Galazka Abstract Heat and mass transfer taking place during growth of Y3Al5O12 (YAG) crystals by the Czochralski method, including inner radiation, is analyzed numerically using a Finite Element Method. For inner radiative heat transfer through the crystal the band approximation model and real transmission characteristics, measured from obtained crystals, are used. The results reveal significant differences in temperature and melt flow for YAG crystals doped with different dopands influencing the optical properties of the crystals. When radiative heat transport through the crystal is taken into account the melt-crystal interface shape is different from that when the radiative transport is not included. Its deflection remains constant over a wide range of crystal rotation rates until it finally rapidly changes in a narrow range of rotation rates. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Transmission spectra of crystals at elevated temperatures for the calculation of internal radiant heat transport during crystal growth , Part 1: The spectrometer and its performanceCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2003D. Schwabe Abstract We report the construction, operation and performance of a transmission spectrometer for the visible to the IR (up to 3.5 ,m wavelength) to measure crystals up to a temperature of 1400 °C. The spectral resolution is almost comparable to that of a commercial spectrometer. The performance of the spectrometer and some problems are demonstrated by spectra of YAG : Nd at different temperatures. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Low-Fluence Q-Switched Neodymium-Doped Yttrium Aluminum Garnet Laser for Melasma with Pre- or Post-Treatment Triple Combination CreamDERMATOLOGIC SURGERY, Issue 6 2010SE-YEONG JEONG MD BACKGROUND Topical triple combination (TC) treatment is considered the primary approach to melasma. Recently, collimated low-fluence 1,064-nm Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser treatment has attracted attention as an alternative approach. OBJECTIVES To compare the clinical efficacy and adverse effects of low-fluence Q-switched Nd:YAG laser when performed before and after treatment with topical TC using a split-face crossover design. METHODS Thirteen patients with melasma received topical treatment with TC cream or 1,064-nm Q-switched Nd:YAG laser treatment on opposite sides of the face for 8 weeks, and then treatments were reversed for 8 weeks. Responses were evaluated using the Melasma Area and Severity Index scoring system, spectrophotometry measurements, and a subjective self-assessment method. RESULTS After 16 weeks, better results were seen in subjective assessments when laser treatment was used after 8 weeks of topical TC treatment than before usage of TC. There were no significant adverse effects with the laser treatments. CONCLUSIONS Laser treatment after topical TC cream was found to be safer and more effective than the post-treatment use of topical agents. The authors have indicated no significant interest with commercial supporters. [source] Comparison of a Long-Pulse Nd:YAG Laser and a Combined 585/1,064-nm Laser for the Treatment of Acne Scars: A Randomized Split-Face Clinical StudyDERMATOLOGIC SURGERY, Issue 11 2009SEONG UK MIN MD BACKGROUND Nonablative laser is gaining popularity because of the low risk of complications, especially in patients with darker skin. OBJECTIVE To compare the efficacy and safety of a long-pulse neodymium-doped yttrium aluminium garnet (Nd:YAG) laser and a combined 585/1,064-nm laser for the treatment of acne scars. MATERIALS AND METHODS Nineteen patients with mild to moderate atrophic acne scars received four long-pulse Nd:YAG laser or combined 585/1,064-nm laser treatment sessions at fortnightly intervals. Treatments were administered randomly in a split-face manner. RESULTS Acne scars showed mild to moderate improvement, with significant Echelle d'évaluation clinique des cicatrices d'acné (ECCA) score reductions, after both treatments. Although intermodality differences were not significant, combined 585/1,064-nm laser was more effective for deep boxcar scars. In patients with combined 585/1,064-nm laser-treated sides that improved more than long-pulse Nd:YAG laser-treated sides, ECCA scores were significantly lower for combined 585/1,064-nm laser treatment. Histologic evaluations revealed significantly greater collagen deposition, although there was no significant difference between the two modalities. Patient satisfaction scores concurred with physicians' evaluations. CONCLUSION Both lasers ameliorated acne scarring with minimal downtime. In light of this finding, optimal outcomes might be achieved when laser treatment types are chosen after considering individual scar type and response. [source] Treatment of Melasma Using Variable Square Pulse Er: YAG Laser ResurfacingDERMATOLOGIC SURGERY, Issue 3 2009RUNGSIMA WANITPHAKDEEDECHA MD BACKGROUND Treatment of melasma remains a challenge. Laser treatments show limited efficacy, with a high rate of recurrence and side effects. Recently, variable-pulsed erbium:yttrium aluminum garnet (Er:YAG) lasers have shown favorable results in skin resurfacing, with minimal downtime and adverse effects. OBJECTIVE To determine the efficacy and side effects of variable square pulsed (VSP) Er:YAG laser resurfacing for treatment of epidermal type melasma. METHODS Twenty Thai women with epidermal-type melasma were treated with two passes of VSP Er:YAG laser resurfacing using a 7-mm spot size, pulse duration of 300 ,s, and a fluence of 0.4 J/cm2. Two treatments were given 1 month apart. Visual analog scale (VAS), Melasma Area and Severity Index (MASI) score and melanin index (MI) were measured at baseline and 1, 2, and 4 months after treatment. RESULTS There was a significant improvement in VAS from baseline at 1-, 2-, and 4-month follow-up visits (p<.001). Significant improvement in MASI score at the 2-month visit from baseline (p=.004) was also observed. The average MI measured using melanin reflectance spectrometry measurements corresponded to MASI score rating. CONCLUSIONS VSP Er:YAG laser resurfacing effectively but temporarily improved epidermal-type melasma. Recurrence was observed after the treatment was discontinued. [source] Effect of Laser Resurfacing on p53 Expression in Photoaged Facial SkinDERMATOLOGIC SURGERY, Issue 6 2007MOETAZ M. EL-DOMYATI MD BACKGROUND p53 overexpression has been reported in photoaged skin. Meanwhile, p53 gene mutations have been implicated as an important factor in the pathogenesis of ultraviolet (UV) light,induced skin cancer. OBJECTIVE The objective was to evaluate the effect of laser resurfacing on the epidermal thickness and expression of p53 in photoaged skin. METHODS Specimens were obtained from the facial skin of 10 patients before and after 3 months and 1 year of treatment using CO2 (five cases) and erbium (Er):YAG (five cases) lasers. Specimens were also obtained from six age-matched controls. These biopsies were used for routine histopathology, histometry, and p53 immunoperoxidase staining. RESULTS Both CO2 and Er:YAG lasers were found to induce a significant decrease in p53 expression in biopsies obtained after 3 months (p=.0004 and .002, respectively) followed by gradual increase (p=.01 in both groups). A significant increase (p<.01) in epidermal thickness was also observed after 1 year of resurfacing. This increase, however, is inversely correlated with the level of p53 expression in such patients. CONCLUSION The decrease in epidermal p53 expression after CO2 and Er:YAG lasers may account for some of the benefits of resurfacing on the epidermis, as well as prevention of actinic neoplasia by adjusting any disturbance in the proliferation/apoptosis balance observed in photoaged facial skin. [source] Nonablative Acne Scar Reduction after a Series of Treatments with a Short-Pulsed 1,064-nm Neodymium:YAG LaserDERMATOLOGIC SURGERY, Issue 8 2006GRAEME M. LIPPER MD BACKGROUND Effective treatment of facial acne scarring presents a major challenge. Nonablative lasers and radiofrequency devices work by thermally stimulating dermal collagen remodeling, thereby softening acne scars in a minimally invasive fashion. One such laser, a 1,064-nm short-pulsed Nd:YAG, uses rapidly scanned low-energy infrared pulses to heat the dermis selectively through the normal dermal microvasculature. OBJECTIVE In this pilot study, the safety and efficacy of a novel short-pulsed Nd:YAG laser were investigated for the treatment of moderate to severe facial acne scarring. MATERIALS AND METHODS Nine of 10 enrolled patients with moderate to severe facial acne scarring received eight sequential 1,064-nm Nd:YAG treatments (laser parameters 14 J/cm2, 0.3 milliseconds, 5-mm spot size, 7-Hz pulse rate, 2,000 pulses per side of face). Patients were graded for the presence and severity of three scar morphologies: superficial (rolling), medium-depth (boxcar), and deep (ice pick). Outcome measures included blinded evaluation of before and after photographs by three physician observers (scar severity score) and patient self-assessment. RESULTS Acne scarring improved in 100% of the nine patients completing the study. Scar severity scores improved by a mean of 29.36% (95% confidence interval, 16.93%,41.79%; p=.006); 89% of patients noted greater than 10% scar improvement. No treatment-related adverse events were seen. CONCLUSION Our findings support the use of a short-pulsed, low-fluence 1,064-nm Nd:YAG laser as a safe, effective treatment for facial acne scarring. Scar improvement was noted in all treated subjects with minimal discomfort and no downtime. This protocol appears to be most effective at reducing scar depth and softening scar contours. [source] Patient Satisfaction and Reported Long-Term Therapeutic Efficacy Associated with 1,320 nm Nd:YAG Laser Treatment of Acne Scarring and PhotoagingDERMATOLOGIC SURGERY, Issue 3 2006ASHISH C. BHATIA BACKGROUND AND OBJECTIVE Nonablative laser treatments have become increasingly used for the treatment of acne scarring and photoaging. While nonablative laser treatments are more convenient and relatively safer than ablative laser resurfacing, efficacy and patient satisfaction with the level of improvement of textural abnormalities in acne scarring and rhytids associated with photoaging needs further study. DESIGN/MATERIALS AND METHODS Structured interviews were performed with 34 patients from a referral-based academic practice who each previously received a series of 6 monthly treatments with a 1,320 nm neodymium:yttrium,aluminum,garnet (Nd:YAG) laser for treatment of acne scarring or photoaging. Topical anesthesia was applied 1 hour before each treatment. Patients were interviewed at least 3 months after cessation of treatment (range 3,12 months). RESULTS Patients tolerated the treatments well. Combined results for acne scarring and photoaging patients were as follows: (a) patient satisfaction with treatment was rated at 62%, and (b) textural improvement was reported at 31% at the end of the six treatments, and 30% at the date of interview. When results were stratified by diagnosis, patient satisfaction was slightly higher for treatment of acne scarring than for photoaging. Overall degree of improvement on a 1,10 scale was 5.4 for acne scarring and 3.8 for wrinkling. CONCLUSION Nonablative treatment with the 1,320 nm Nd:YAG laser induced significant patient-reported improvement in both acne scarring and photoaging. The majority of patients reported satisfaction with the degree of improvement. [source] Variable-Pulse Nd:YAG Laser in the Treatment of Facial TelangiectasiasDERMATOLOGIC SURGERY, Issue 1 2006AVERY A. BEVIN MD BACKGROUND Variable-pulse 1,064 nm wavelength lasers have been used with good effectiveness on leg telangiectasias and reticular veins and have shown promising results on facial telangiectasias as well. OBJECTIVE To investigate the effectiveness of a variable-pulse neodymium:yttrium-aluminum-garnet (Nd:YAG) laser using a small spot size in the treatment of facial telangi-ectasias. METHODS Eight male patients (mean age 75 years) underwent a single treatment session using a variable-pulse 1.5 mm spot size Nd:YAG laser with epidermal cooling. Telangiectasia diameters were 0.3 to 2.0 mm. Test sites were performed using three pulse widths (3, 20, and 60 ms), with fluences varying depending on vessel size and response. Full treatments were per-formed using test parameters giving the best response. Thirteen weeks later, the patients returned for final evaluation and satisfaction rating. RESULTS Fluences ranged from 226 to 425 J/cm2, with smaller vessels requiring larger energies. Pulse duration was equally divided between the 20 and 60 ms settings. The shortest pulse width (3 ms) was inferior in all patients. Longer pulse durations achieved superior vessel elimination with minimal immediate purpura and no postinammatory hyperpigmentation. The average mean vessel clearance was 26 to 50% in half of the patients and 51 to 75% in the other half as evaluated by three unbiased dermatologists with extensive laser experience. CONCLUSION A small,spot size Nd:YAG laser using a pulse width of 20 ms or higher appears to be effective in clearing a significant percentage of facial telangectasias with a single pass. The side effects were minimal. [source] Successful Treatment of a Cosmetic Tattoo Using a Combination of LasersDERMATOLOGIC SURGERY, Issue 1 2004Karen Rebecca Suchin MD Background. Cosmetic tattoos are becoming more popular and are often composed of several colors. Tattoo pigments containing ferric oxide and titanium dioxide can change to a blue-black color after exposure to Q-switched lasers that can be permanent. Objective. Using a patient who presented with rouge tattoos on the cheeks as an example, we describe a useful approach to laser treatment of cosmetic tattoos. Methods. Test areas were done with the Q-switched Nd:YAG at both 532 and 1064 nm and with the pulsed-dye laser at 595 nm. Results. Although an immediate blue-black color change occurred after treatment with the Nd:YAG at 532 and 1064 nm, sequential treatments at 1064 nm produced a near complete clearance of the tattoos. The pulsed-dye laser was used to remove subtle pink tones. Conclusion. Performing small test areas before complete treatment and using several laser wavelengths throughout the course of therapy are essential to the successful treatment of cosmetic tattoos. [source] Laser-Assisted Hair Transplantation: Histologic Comparison Between CO2 and Ho:YAG LasersDERMATOLOGIC SURGERY, Issue 4 2001Eugene A. Chu MD Background. Various laser wavelengths and devices have been advocated for use in the creation of recipient channels during hair transplant surgery, including flash-scanned CO2, Ho:YAG (, = 2.12 ,m), and Er:YAG (, = 2.94 ,m). Objective. To determine the tissue injury caused by flash-scanned CO2 and pulsed Ho:YAG lasers during the creation of hair transplant recipient channels and to assess the efficacy of the Ho:YAG laser. Methods. Recipient channels were created in vivo in human scalp tissue using both lasers, and were excised and prepared for histologic examination. Optical micrometry of tissue sections was used to assess thermal injury. Results. The Ho:YAG laser created jagged, irregular-shaped channels with larger zones of thermal injury (superficial deepithelialization, thermal necrosis, and thermal damage). In contrast, the CO2 laser produced well-defined cylindrically shaped channels free of cellular debris with minimal epithelial disruption and significantly less lateral thermal injury. Conclusion. Given that the Ho:YAG produced larger regions of thermal injury and recipient channels that were unacceptable for graft, the CO2 laser remains the better choice for the creation of recipient channels during hair transplant surgery. However, ongoing research will be necessary to determine the optimal laser wavelength and/or devices for this procedure. [source] Fluorescence-controlled Er:YAG laser for caries removal in permanent teeth: a randomized clinical trialEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2008Henrik Dommisch The aim of this randomized clinical study was to compare the efficacy of a fluorescence-controlled erbium-loaded yttrium aluminum garnet (Er:YAG) laser with conventional bur treatment for caries therapy in adults. Twenty-six patients with 102 carious lesions were treated using either the Er:YAG laser, at threshold levels of 7, 8, 9, and 10 [U], or rotary burs. Both techniques were applied to each lesion at separate locations. After treatment, dentine samples were obtained using a carbide bur. The viable counts of Streptococcus mutans (SM) and lactobacilli (LB) [expressed as colony-forming units (log10 CFUs)], treatment time, pain, vibration, and sound intensity were determined. The median numbers of CFUs for SM and LB were not statistically different between laser and bur treatment at threshold levels 7 and 8 [U]. At threshold levels 9 and 10 [U], the median number of CFUs for LB [1.11 (range: 0.00,2.04)] were significantly higher following laser treatment than following bur treatment [0.30 (range: 0.00,0.60)]. The results indicate that treatment with a fluorescence-controlled Er:YAG laser at threshold levels of 7 and 8 removed caries to a level similar to that achieved using conventional bur treatment, with clinically irrelevant amounts of remaining bacteria. Although more time consuming, laser treatment provided higher patient comfort than bur treatment. [source] Synthesis of Nd-YAG material by citrate-nitrate sol-gel combustion route,ADVANCED ENGINEERING MATERIALS, Issue 4 2007L. Costa Polycrystalline, Neodymium doped, yttrium aluminum garnet Nd:YAG is a functional materials for solid-state lasers. The synthesis of Nd:YAG powders requires a strict control of the precursor reactivity and composition. Sol-gel citrate-based methods increase the chemical homogeneity and reactivity of the precursor powder. Calcination performed around 900,°C leads to the formation of pure YAG phase at temperatures much lower than the temperature required for the solid-state reaction (1600,°C). [source] Modifying the Output Characteristics of an Organic Light-Emitting Device by Refractive-Index Modulation,ADVANCED FUNCTIONAL MATERIALS, Issue 18 2006T. Höfler Abstract In order to modify the output characteristics of organic light-emitting devices (OLEDs), the optical properties of an active layer within the device are patterned without introducing any thickness modulation. For this purpose a new conjugated copolymer, which serves as a hole-transporting material and at the same time can be index patterned using UV techniques, is synthesized. Poly(VC- co -VBT) (VC: N -vinylcarbazole; VBT: 4-vinylbenzyl thiocyanate) is prepared by free-radical copolymerization of VC and VBT. The material contains photoreactive thiocyanate groups that enable altering of the material's refractive index under UV illumination. This copolymer is employed as a patternable hole-transporting layer in multilayer OLEDs. Refractive-index gratings in poly(VC- co -VBT) are inscribed using a holographic setup based upon a Lloyd mirror configuration. The fourth harmonic of a Nd:YAG (YAG: yttrium aluminum garnet) laser (266,nm) serves as the UV source. In this way 1D photonic structures are integrated in an OLED containing AlQ3 (tris(8-hydroxyquinoline) aluminum) as the emitting species. It is assured that only a periodical change of the refractive index (,n,=,0.006 at ,,=,540,nm) is generated in the active material but no surface-relief gratings are generated. The patterned devices show more forward-directed out-coupling behavior than unstructured devices (increase in luminosity by a factor of five for a perpendicular viewing direction). This effect is most likely due to Bragg scattering. For these multilayer structures, optimum outcoupling was observed for grating periods ,,,,390,nm. [source] Ex vivo study of the adhesion of an epoxy-based sealer to human dentine submitted to irradiation with Er : YAG and Nd : YAG lasersINTERNATIONAL ENDODONTIC JOURNAL, Issue 12 2005M. D. Sousa-Neto Abstract Aim, To evaluate the adhesion of an epoxy-based sealer to human dentine submitted to irradiation with Er : YAG or Nd : YAG laser at various parameters. Methodology, Ninety maxillary canine teeth were sectioned transversely at the cemento-enamel junction and at the root tip to leave an 8-mm-long cylinder. The tooth specimen was centred in a metallic ring (16 mm diameter and 8 mm height) and embedded in acrylic resin. The root canals were prepared using a low-speed handpiece and a conical diamond bur, which was attached to a paralleling device. This bur was lowered to a depth previously determined by a silicone stop. Specimens were divided into nine groups: group I, dentine was treated with 2 mL of 17% EDTAC for 5 min. Groups II,V were irradiated with Er : YAG laser at the following parameters: group II , 8 Hz and 200 mJ input (120 mJ output); group III , 8 Hz and 400 mJ input (240 mJ output); group IV , 16 Hz and 200 mJ input (120 mJ output); group V , 16 Hz and 400 mJ input (240 mJ output). Groups VI,IX were irradiated with Nd : YAG laser at the following parameters: group VI , 10 Hz and 1 W input (0.4 W output); group VII , 10 Hz and 2 W input (0.8 W output); group VIII , 15 Hz and 1 W input (0.4 W output); group IX , 15 Hz and 2 W input (0.8 W output). The root canals were filled with an epoxy-based root canal sealer and submitted to a push-out test. Results, Statistical analysis showed significant differences (P < 0.01) between Er : YAG and Nd : YAG laser treatments at the higher frequencies compared with 17% EDTAC. Greater adhesion values were obtained for groups IV and V (Er : YAG laser) and groups VIII and IX (Nd : YAG laser), which were statistically different from groups II and III (Er : YAG laser) and groups VI and VII (Nd : YAG laser). Treatment with only 17% EDTAC had the lowest adhesion values. Conclusions, An increase in frequency, independent of power settings, of the lasers used in this study increased adhesion of an epoxy-based root canal sealer. [source] Lasers for facial rejuvenation: a reviewINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 6 2003Evangelia Papadavid MD Background Different types of laser are used for resurfacing and collagen remodeling in cutaneous laser surgery. Methods A systematic review was performed of the different types of laser currently employed for skin rejuvenation. These systems are either ablative [high-energy pulsed or scanned carbon dioxide (CO2) laser emitting at a wavelength of 10,600 nm, single- or variable-pulse or dual ablative/coagulative mode erbium:yttrium aluminum garnet (Er:YAG) laser emitting at a wavelength of 2940 nm, or systems combining both 10,600 nm and 2940 nm wavelengths] or nonablative [Q-switched neodymium:yttrium aluminum garnet (Nd:YAG) laser emitting at a wavelength of 1064 nm, Nd:YAG laser emitting at a wavelength of 1320 nm, or diode laser emitting at a wavelength of 1450 nm]. Different protocols, patient selection, treatment techniques, and complications are discussed for each system. Results New-generation CO2 resurfacing lasers have been successful in the treatment of photodamaged skin and scarring, with a postoperative morbidity dependent on the depth of thermal damage. Because of its minimal penetration, the pulsed Er:YAG laser, usually used in the treatment of more superficial rhytides, produces less postoperative morbidity. Novel ablative systems have been developed and a further understanding of laser,tissue interaction has led to the design of nonablative systems for the treatment of rhytides, scarring, and photodamaged skin, the efficacy and profile of which remain to be evaluated in the long term. Conclusions There are several effective techniques for scar revision and the treatment of aged skin, but all have their drawbacks due to a lack of precise depth control and unwanted damage to the lower layers of the dermis. The Er:YAG laser is the treatment of choice for fine lines and superficial scars, whereas the CO2 laser is better for deeper rhytides and scars. In the future, a combination of lasers may be used for facial rejuvenation. [source] Pulsed erbium:YAG laser-assisted autologous epidermal punch grafting in vitiligoINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 11 2000Mukta Sachdev MD Background A pilot study was conducted to evaluate the efficacy and safety of pulsed erbium:YAG laser ablation of autologous minipunch grafted sites for the treatment of refractory or stable vitiligo. Methods Thirteen patients, seven men and six women, aged between 19 and 58 years, with Fitzpatrick skin types ranging from type IV to VI, were grafted. The pulsed erbium: YAG laser was used to create recipient graft sites. Results Repigmentation was observed in 12 out of 13 patients. Failure of grafts to repigment ranged from 3% to 100%. No untoward side-effects of surgery were noted. Conclusions Using an erbium:YAG laser to create graft recipient sites permits the survival of punch harvested grafts and the spread of pigmentation to the surrounding skin. [source] Neodymium-YAG Laser for hemangiomas and vascular malformations , long term resultsJOURNAL DER DEUTSCHEN DERMATOLOGISCHEN GESELLSCHAFT, Issue 6 2005Die Behandlung von Hämangiomen und vaskulären Fehlbildungen mit dem Neodymium-YAG-Laser, Langzeitergebnisse Hämangiom; Lasertherapie; Nd:YAG-Laser; vaskuläre Malformation Summary Background: Hemangiomas and vascular malformations are the most common vascular lesions of infancy. Different lasers can be used for treatment. Nd:YAG laser photocoagulation is particularly effective because of its deep penetration into tissue. Patients and methods: Thirty-one patients, aged from three months to 18,years, with voluminous hemangiomas and venous malformations were treated with a cw-neodymium:YAG laser. The quartz fibre was used in percutaneous and intralesional technique. Long-term follow-up data were acquired by clinical control or a patient questionnaire for a maximal period of eight years. Twenty patients could be evaluated. Results: In the group with hemangiomas (n,=,15), three cases showed nearly complete remission (> 90 %), ten cases had a partial reduction in size (50,,,90 %), in one case there was stable disease and in one case tumor growth. In the group with venous malformations (n,=,5) two cases showed an excellent response (> 90 %), one case a moderate response (25,,,50 %) and in two cases there was no improvement. Adverse effects included scars (40 %), hyper- and hypopigmentation (23 %), mild atrophy (20 %) and a wrinkled texture (17 %). After maximal reduction in size, 30 % of the patients were not satisfied with the laser treatment outcome and elected surgical excision of the residual lesion. Conclusions: The neodymium:yttrium aluminium garnet (Nd:YAG) laser with percutaneous or intralesional application technique is a valuable tool for selected patients with hemangiomas and venous malformations. Zusammenfassung Hintergrund: Hämangiome und vaskuläre Malformationen sind die häufigsten Gefäßfehlbildungen in der Kindheit. Eine Therapieoption stellt die Laserbehandlung dar. Der Nd:YAG-Laser ist besonders effektiv aufgrund seiner hohen Eindringtiefe ins Gewebe. Patienten und Methodik: Insgesamt wurden 31,Patienten im Alter zwischen drei Monaten und achtzehn Jahren mit voluminösen Hämangiomen und venösen Malformationen mit einem cw-Neodymium:YAG-Laser behandelt. Die Laserfaser wurde in perkutaner und intraläsionaler Technik angewendet. Die Nachbeobachtung über einen Zeitraum von maximal acht Jahren erfolgte mittels klinischer Kontrollen oder einem Patientenfragebogen. Von den insgesamt 31,Patienten konnten 20 ausgewertet werden. Ergebnisse: In der Gruppe der Patienten mit Hämangiomen zeigten drei Patienten eine fast vollständige Rückbildung (> 90 %), zehn Patienten eine partielle Rückbildung (50,,,90 %), in einem Fall zeigte sich ein unveränderter Befund und bei einem Patienten beobachteten wir weiterhin Wachstum. In der Gruppe der Patienten mit venösen Malformationen zeigten zwei Patienten ein exzellentes Ansprechen (> 90 %), ein Patient ein moderates Ansprechen (25,,,50 %) und bei zwei Patienten kam es zu keiner Verbesserung. Nebenwirkungen beinhalteten Narben (40 %), Hyper- und Hypopigmentierungen (23 %), geringe Atrophie (20 %) und eine Hautfältelung. Nach vollständiger Rückbildung waren 30 % der Patienten unzufrieden mit dem Ergebnis und unterzogen sich einer operativen Entfernung der Residuen. Schlußfolgerungen: Der Nd:YAG-Laser mit perkutaner und intraläsionaler Applikationstechnik stellt eine wirksame Methode zur Behandlung ausgewählter Patienten mit Hämangiomen und venösen Malformationen dar. [source] Comparison of fluoride and sapphire optical fibers for Er: YAG laser lithotripsyJOURNAL OF BIOPHOTONICS, Issue 5-6 2010Jinze Qiu Abstract The long-pulse (200,350 ,s) Holmium: YAG (Ho: YAG) laser (, = 2.12 ,m) is used extensively in urology for laser lithotripsy. The long-pulse Erbium: YAG (Er: YAG) laser (, = 2.94 ,m) fragments urinary calculi up to 5 times more efficiently than the Ho: YAG laser, however, no optical fibers are available to transmit efficiently 2.94 ,m laser light for laser lithotripsy. We report results of a study evaluating a fluoride glass fiber to transmit Er: YAG laser light for laser lithotripsy and compare to a sapphire fiber that provides good transmission of Er: YAG light at low irradiance. The fluoride fiber provides superior light transmission efficiency over the sapphire fiber at an Er: YAG wavelength (2.94 ,m). The sapphire fiber provides a more durable and robust delivery waveguide than the fluoride fiber when ablating urinary calculi in contact mode. Results of our study suggest that further development to improve performance of fluoride fibers for laser lithotripsy is warranted. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Morphology, chemical structure and diffusion processes of root surface after Er:YAG and Nd:YAG laser irradiationJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 6 2001B. Ga Abstract Objectives: The aim of this in vitro study was to evaluate the effects of Er:YAG and Nd:YAG lasers on morphology, chemical structure and diffusion processes of the root surface. Material and methods: 60 root samples were irradiated for 1 min each either with 60 mJ/p, 80mJ/p and 100mJ/p using Er:YAG laser or with 0.5W, 1.0W and 1.5W using Nd:YAG laser. Scanning electron microscopy (SEM) was used to determine the morphology, infrared (IR) spectroscopy to assess the alterations in chemical structure and one dimensional electron paramagnetic resonance imaging (1-D EPRI) was used to estimate the diffusion coefficients in dental root samples. Results: Er:YAG laser treatment resulted in deep crater formation with exposed dentin. Morphological alterations of root surface after Nd:YAG laser irradiation included cracks, crater formation, meltdown of the root mineral and resolidified porous globules formation. Er:YAG laser failed to alter the intensity of Amide peaks I, II or III. In contrast, treatment with Nd:YAG laser, using the highest power setting of 1.5W, reduced the intensity of Amide peak II and III in comparison to the control. The diffusion coefficients were increased significantly in all Er:YAG and Nd:YAG treated root samples. Conclusion: This study demonstrated that Er:YAG laser influences only on morphology and diffusion processes of root surfaces, while Nd:YAG laser also alters the chemical structure of root proteins. Zusammenfassung Ziele: Das Ziel dieser in vitro Studie war es, die Wirkung von Er:YAG- und Nd:YAG-Laser auf die Morphologie, chemische Struktur und die Diffusionsprozesse zu evaluieren. Material und Methoden: 60 Proben von Wurzeln wurden für eine Minute entweder mit einem Er:YAG-Laser und 60 mJ/p, 80 mJ/p und 100 mJ/p oder einem Nd:YAGLaser und 0.5 W, 1.0 W und 1.5 W bestrahlt. Die Rasterelektronenmikroskopie (REM) wurde verwendet um die Morphologie zu bestimmen, Infrarotspektroskopie (IR) zur Messung der Veränderung in der chemischen Struktur und die eindimensionale paramagnetische Elektronenresonanz-Bildgebung (1-D EPRI) wurde verwendet um die Diffusions-Koeffizienten in den dentalen Wurzelproben abzuschätzen. Ergebnisse: Die Behandlung mit dem Er: YAG-Laser resultierte in der Ausbildung tiefer Krater mit exponiertem Dentin. Die morphologischen Veränderungen der Wurzeloberfläche nach Bestrahlung mit dem Nd: YAG-Laser waren Brüche, Kraterbildung, Aufschmelzen des Wurzelminerals und Bildung wiederverfestigter poröser Globuli. Mit dem Er:YAG-Laser gelang es nicht die Intensität der Amid-peaks I, II oder III zu verändern. Im Gegensatz dazu reduzierte die Behandlung mit dem Nd:YAG-Laser im Vergleich mit der Kontrolle bei der höchsten Leistungseinstellung von 1.5 W die Intensität der Amid-Peaks II und III. In allen mit Er: YAG und Nd:YAG behandelten Wurzelproben waren die Wurzeldiffusionskoeffizienten signifikant erhöht. Schlussfolgerung: Diese Studie demonstrierte, dass der Er:YAG-Laser nur die Morphologie und die Diffusionsprozesse der Wurzeloberfläche beeinflusst, während der Nd: YAG-Laser auch die chemische Struktur der Wurzelproteine verändert. Résumé Morphologie, structure chimique et processus de diffusion de surfaces radiculaires après irradiation au lasers Er:YAG et Nd:YAG But: Le but de cette étude in vitro était d'évaluer les effets des lasers Er:YAG et Nd:YAG sur la morphologie, la structure chimique et les processus de diffusion des surfaces radiculaires. Matériaux et méthodes: 60 échantillons de racines furent irradiés pendant 1 min chacun par 60 mJ/p, 80 mJ/p et 100 mJ/p avec le laser Er:YAG ou par 0.5 W, 1.0 W et 1.5 W avec le laser Nd:YAG. La microscopie électronique à balayage (SEM) a été utilisée pour déterminer la morphologie, la spectroscopie infra rouge pour mettre en évidence les altérations de la structure chimique et l'imagerie en une dimension par résonnance magnétique électronique (1-DEPRI) fut utilisée pour estimer les coefficients de diffusion dans les échantillons de racines dentaires. Résultats: Le traitement au laser Er:YAG entrainait la formation de cratères profonds avec de la detine exposée. Les altérations morphologiques de la surface radiculaire après irradiation au laser Nd:YAG prenaient la forme de félures, de cratères, fusion du minéral radiculaire et formation de globules poreux resolidifiés. Le laser Er:YAG n'arrivait pas à altérer l'intensité des pics Amide I, II our III. Au contraire, le traitement au laser Nd:YAG, en utilisant la plus haute puissance de 1.5 W, réduisait l'intensité des pics Amide II et III, par rapport au contrôle. Les coefficients de diffusion étaient significativement augmentés pour toutes les racines traitées par les lasers Er:YAG et Nd:YAG. Conclusions: Cette étude démontre que le laser Er:YAG a une influence sur seulement la morphologie et les processus de diffusion des surfaces radiculaires alors que le laser Nd:YAG modifie également la structure chinique des protéines radiculaires. [source] ADHESION TO LASER-PREPARED TOOTH STRUCTUREJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 6 2006MS Author, Thomas J. Hilton DMD The use of Er:YAG (erbium : yttrium aluminum garnet and Er,Cr:YAG (erbium, chromium : yttrium scandium gallium garnet) lasers for tooth preparation has received much attention in recent years. Several advantages have been attributed to these devices, including a reduced need for local anesthesia for tooth preparation, less vibration to the patient, and more conservative cavity preparation. Another purported advantage has been the contention that adhesion to tooth structure is enhanced compared with other means of cavity preparation, even to the point of eliminating the need for conditioning and/or etching prior to adhesive system application. As the use of bonded, esthetic restorations has increased, it is important to know if this purported bonding advantage is valid. This Critical Appraisal examines evidence in the peer-reviewed scientific literature that contradicts this contention, and discusses concerns regarding the use of lasers in cavity preparation. [source] A fast, reproducible and low-cost method for sequence deconvolution of ,on-bead' peptides via ,on-target' maldi-TOF/TOF mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 3 2010Giulio A. Amadei Abstract A novel approach to high-throughput sequence deconvolution of on-bead small peptides (MW < 2000 Da) using on-target MALDI-TOF/TOF instrumentation is presented. Short peptides of pentamer and octamer length, covalently attached to TentaGel polystyrene beads through a photolabile linker, were placed onto the MALDI target, apportioned with suitable matrix (2,5-dihydroxybenzoic acid) and then hit with the instrument laser (Nd : YAG, 355 nm). This induced easy and highly reproducible photochemical cleavage, desorption (MS mode) and fragmentation (MS/MS mode). Peptide fragments were identified with a mass accuracy of 0.1 Da of the expected values. This technique significantly accelerates the sequence determination of positive peptide hits obtained from random combinatorial libraries when screening against biological targets, paving the way for a rapid and efficient method to identify molecular imaging ligands specific to pathological targets in cancer and other diseases. Copyright © 2009 John Wiley & Sons, Ltd. [source] Scanning electron microscopy and transmission electron microscopy microstructural investigation of high-speed tool steel after Nd:YAG pulsed laser meltingJOURNAL OF MICROSCOPY, Issue 1 2006S. KAC Summary This article presents the microstructure of a pulsed Nd:YAG laser-melted high-speed steel, namely HS6-5-2. The high chemical homogeneity and fine structure of the melted zone was attributed to high cooling rates due to the short duration of interaction with the Nd:YAG pulsed laser radiation and the relatively small volume of the melted material. The structure obtained in the surface layer after laser melting has a high level of hardness and shows improved wear resistance. [source] The structure and mechanical properties of amorphous and nanocrystalline Fe,Si,B alloysJOURNAL OF MICROSCOPY, Issue 1 2006A. SYPIE Summary This article describes the results of investigations of the microstructure of failure surfaces and the mechanism of deformation of an amorphous Fe80Si11B9 alloy, nanocrystallized with the use of Nd:YAG pulsed laser heating. The research included ,in situ' tensile testing in a scanning electron microscope. Mechanical properties were also measured on an Instron-type machine for the amorphous and nanocrystalline alloys. The mechanical tensile tests performed on the amorphous and nanocrystalline samples showed a ductile fracture surface with very high fracture stress. Detailed observations of the flow deformation and fractures revealed the relationship between the quenched-in crystalline and mechanical behaviour. [source] Effect of Er:YAG and Diode lasers on the adhesion of blood components and on the morphology of irradiated root surfacesJOURNAL OF PERIODONTAL RESEARCH, Issue 5 2006Letícia Helena Theodoro Objective:, The aim of this study was to evaluate in vitro, by scanning electron microscopy (SEM), the adhesion of blood components on root surfaces irradiated with Er:YAG (2.94 µm) and GaAlAs Diode (808 nm) lasers and the effects on the morphology of irradiated root surfaces. Methods:, One hundred samples of human teeth were obtained. They were previously planed and scaled with manual instruments and divided into five groups of 20 samples each: G1 (control group) , absence of treatment; G2 , Er:YAG laser (7.6 J/cm2); G3 , Er:YAG laser (12.9 J/cm2); G4 , Diode laser (90 J/cm2) and G5 , Diode laser (108 J/cm2). After these treatments, 10 samples of each group received a blood tissue but the remaining 10 did not. After laboratory treatments, the samples were obtained by SEM, the photomicrographs were analysed by the score of adhesion of blood components and the results were statistically analysed (Kruskall,Wallis and Mann,Whitney test). Results:, In relation to the adhesion of blood components, the study showed no significant differences between the control group and the groups treated with Er:YAG laser (p = 0.9633 and 0.6229). Diode laser radiation was less effective than control group and Er:YAG laser radiation (p < 0.01). Conclusions:, None of the proposed treatments increased the adhesion of blood components in a significant way when compared to the control group. Although the Er:YAG laser did not interfere in the adhesion of blood components, it caused more changes on the root surface, whereas the Diode laser inhibited the adhesion. [source] Hot Isostatic Pressing of Transparent Nd:YAG CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2009Sang-Ho Lee This paper demonstrates that fine-grained (2,3 ,m), transparent Nd:YAG can be achieved at SiO2 doping levels as low as 0.02 wt% by the sinter plus hot isostatic pressing (HIP) approach. Fine grain size is assured by sintering to 98% density, in order to limit grain growth, followed by HIP. Unlike dry-pressed samples, tape-cast samples were free of large, agglomerate-related pores after sintering, and thus high transparency (i.e., >80% transmission at 1064 nm) could be achieved by HIP at <1750°C along with lower silica levels, thereby avoiding conditions shown to cause exaggerated grain growth. Grain growth was substantially limited at lower SiO2 levels because silica is soluble in the YAG lattice up to ,0.02,0.1 wt% at 1750°C, thus allowing sintering and grain growth to occur by solid-state diffusional processes. In contrast, liquid phase enhanced densification and grain growth occur at ,0.08,0.14 wt% SiO2, especially at higher temperatures, because the SiO2 solubility limit is exceeded. [source] Effect of Sc Substitution for Al on the Optical Properties of Transparent Ce:YSAG CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2008Tao Feng Transparent Ce:YAG (Ce:Y3Al5O12) and Ce:YSAG (Ce:Y3ScxAl5,xO12) ceramics have been successfully fabricated using Sc3+ to substitute for Al3+ in Ce:YAG. The effect of Sc substitution on the luminescent properties of Ce:YAG has been investigated. At the substitution level of 20 at.% of Sc3+ for Al3+, the emission intensity of Ce:YSAG is the highest. Meanwhile, the doping of Sc into Ce:YAG lattice broadened both the absorption and emission bands, which is believed to be due to the inhomogeneous broadening of the 5d energy level of Ce3+ caused by the Sc3+ substitution. [source] Atomistic Modeling Study of Surface Segregation in Nd:YAGJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2006Ulrich Aschauer This study investigates the composition of free surfaces of neodymium-doped yttrium,aluminum,garnet, using energy minimization techniques. Atomistic modeling shows that the dopant is concentrated in a zone within 5 Å of the surface, the enrichment factor being around 1300 when comparing surfaces with bulk concentrations. It is shown that the (111) surface can incorporate 1.8 times as much Nd as the (110) surface, the latter commonly found in YAG morphologies. Our results indicate that by using nanocrystalline ceramics and by modifying crystal growth to form (111) surfaces, the Nd content and thus the laser power may be significantly increased. [source] Synthesis of Yttrium,Aluminum,Garnet Hollow Microspheres by Reverse-Emulsion TechniqueJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2006Minati Chatterjee Yttrium,aluminum,garnet (YAG, Y3Al5O12) hollow microspheres were synthesized by reverse-emulsion (w/o) technique starting with aqua-based precursors of oxides. The non-ionic surfactant was used as the emulsifying agent. The gel powders were calcined at 700°,1200°C. The synthesized powders were characterized by differential thermal analysis (DTA), thermogravimetry, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The appearance of an exothermic peak at 932°C in the DTA curve revealed the crystallization of YAG, which was further confirmed by XRD and FTIR studies. SEM confirmed the formation of hollow microspheres. [source] | ||||||||||||||||||||||||||||||||||