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Spot Size (spot + size)

Distribution by Scientific Domains

Medical Sciences	64%
Chemistry	24%
Polymers and Materials Science	5%
Physics and Astronomy	3%

Selected Abstracts

Sample Target Substrates with Reduced Spot Size for MALDI-TOF Mass Spectrometry Based on Patterned Self-Assembled Monolayers

ADVANCED FUNCTIONAL MATERIALS, Issue 17 2009
Nicole Herzer
Abstract The wetting properties of structured self-assembled monolayers are used to fabricate sample target substrates for MALDI-TOF mass spectrometry. Combining the advantages of a hydrophobic-hydrophilic surface pattern and the possibility of obtaining micrometer patterns allows an increase in the sensitivity of MALDI-TOF mass spectrometry analysis and a reduction in the traceable concentration down to fmol µL,1. This easy, cheap and fast patterning process provides substrates that allow sensitive, high-resolution mass spectrometry of dilute solutions. [source]

Subretinal pigment dispersion following transpupillary thermotherapy for choroidal melanoma

ACTA OPHTHALMOLOGICA, Issue 4 2002
Hayyam Kiratli
ABSTRACT. Purpose:, To report the case of a patient who developed considerable subretinal pigment/debris dispersion following transpupillary thermotherapy (TTT). This type of tumour response is extremely rare with this relatively new therapeutic modality. Methods:, A 50-year-old man with a left juxtapapillary choroidal melanoma measuring 8 × 6 × 4.3 mm was treated with 810 nm diode laser TTT administered in two sessions. Spot size was 3 mm and the power setting was 450 mW. Results:, Four months after the first treatment session, a considerable amount of pigment/debris was seen to have dispersed in the subretinal space, accumulating mainly in the macular area. Over a 12-month follow-up, the tumour showed progressive shrinkage without any change in the amount or location of the shed pigment/debris. No new tumour formation, recurrence or systemic metastases were detected. Conclusion:, Subretinal pigment/debris dispersion is an unusual complication after TTT and requires close follow-up. There has been no short-term compromise on the life or visual acuity of this patient. [source]

Laser Hair Removal: Long-Term Results with a 755 nm Alexandrite Laser

DERMATOLOGIC SURGERY, Issue 11 2001
Sorin Eremia MD
Background. Hypertrichosis is a common problem for which laser hair removal is becoming the treatment of choice. Optimal wavelength, pulse duration, spot size, fluence, and skin cooling parameters for various skin types have not yet been firmly established. Objective. To evaluate the long-term efficacy and safety of a 3-msec 755 nm alexandrite laser equipped with a cryogen cooling device for patients with Fitzpatrick skin types I,V. Methods. Eighty-nine untanned patients with skin types I,V underwent a total of 492 treatments of laser hair removal over a 15-month period. Each patient in the study underwent a minimum of three treatment sessions spaced 4,6 weeks apart (mean treatments 5.6). Retrospective chart review and patient interviews were used to establish hair reduction results. Treatment sites included the axillae, bikini, extremities, face, and trunk. A 3-msec pulse width, 755 nm alexandrite laser equipped with a cryogen spray cooling device was used in this study. Spot sizes of 10,15 mm were used. A spot size of 10 mm was used for fluences greater than 40 J/cm2, a spot size of 12 mm was used for fluences of 35,40 J/cm2, and spot sizes of 12 and 15 mm were used for fluences less than 30 J/cm2. Fluences ranging from 20 to 50 J/cm2 (mean fluence 36 J/cm2) were used. Results. The patients had a mean 74% hair reduction. Skin type I patients had an average of 78.5% hair reduction using a mean fluence of 40 J/cm2 (35,50 J/cm2) and a 10,12 mm spot size (12 mm in more than 95% of treatments). Skin type II patients had a mean 74.3% hair reduction using a mean fluence of 38 J/cm2 (30,40 J/cm2) and a 12,15 mm spot size. Skin type III patients had a mean 73.4% hair reduction using a mean fluence of 37 J/cm2 (25,40 J/cm2) and a 12,15 mm spot size. Skin type IV patients had a mean 71.0% hair reduction using a mean fluence of 31 J/cm2 (25,35 J/cm2) and a 12,15 mm spot size. A patient with skin type V had a 60% hair reduction using a mean fluence of 23 J/cm2 (20,25 J/cm2) and a 12,15 mm spot size. The efficiency of hair removal directly correlates significantly with the fluence used. Rare side effects included transient postinflammatory hyperpigmentation (n = 9; 10%), burn with blisters (n = 1; 1%), and postinflammatory hypopigmentation (n = 2; 2%). All complications resolved without permanent scarring. Conclusion. The 3-msec cryogen cooling-equipped alexandrite laser can safely and effectively achieve long-term hair removal in patients with skin types I,V. The best results are achieved in untanned patients with skin types I,IV. [source]

Treatment of Melasma Using Variable Square Pulse Er: YAG Laser Resurfacing

DERMATOLOGIC SURGERY, Issue 3 2009
RUNGSIMA 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]

Minimally Ablative Erbium:YAG Laser Resurfacing of Facial Atrophic Acne Scars in Asian Skin: A Pilot Study

DERMATOLOGIC SURGERY, Issue 5 2008
YONG-KWANG TAY MD
BACKGROUND Atrophic scars are dermal depressions caused by collagen damage most commonly occurring after inflammatory acne vulgaris. There are little published data regarding the effectiveness and safety of minimally invasive lasers in the treatment of atrophic acne scars in darker skin types. OBJECTIVE The purpose was to evaluate the efficacy and safety of a low-fluence 2,940-nm erbium:YAG laser in the treatment of atrophic acne scars in Asian patients. MATERIALS AND METHODS Nine patients aged 19 to 45 years with mild to moderate atrophic facial scars and Skin Types IV and V were treated with topical anesthesia and one to two passes with an erbium:YAG laser two times at 1-month intervals. Treatment parameters were 6-mm spot size, fluence of 400 mJ, pulse duration of 300 ,s, and repetition rate of 2 Hz. RESULTS At 2 months after the last treatment, mild to moderate clinical improvement was noted in all patients compared to baseline. Treatment was well tolerated. Side effects consisted of posttreatment erythema, peeling, and crusting, which resolved within 1 to 2 weeks. There was no postinflammatory hyper- or hypopigmentation, blistering, or hypertrophic scarring. CONCLUSION Low-fluence erbium:YAG facial resurfacing was effective and safe in patients with mild to moderately severe atrophic acne scarring. [source]

Nonablative Acne Scar Reduction after a Series of Treatments with a Short-Pulsed 1,064-nm Neodymium:YAG Laser

DERMATOLOGIC SURGERY, Issue 8 2006
GRAEME 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]

Variable-Pulse Nd:YAG Laser in the Treatment of Facial Telangiectasias

DERMATOLOGIC SURGERY, Issue 1 2006
AVERY 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]

Clear Cell Acanthoma Successfully Treated with a Carbon Dioxide Laser

DERMATOLOGIC SURGERY, Issue 10 2005
Ching-Chi Chi MD
Background. The treatment of choice for clear cell acanthoma (CCA) is excision. Resolution after cryotherapy has also been reported but requires three to four courses of treatment. Objective. To demonstrate three CCA lesions in two patients successfully treated with a carbon dioxide (CO2) laser. Methods. Under local anesthesia, these lesions were vaporized by using a CO2 laser in the Silktouch mode with a spot size of 5 mm and a fluence of 20 J/cm2. Two to six passes, as needed, were delivered until the tumor was completely removed. Results. Pain was minimal or nonexistent during and after the operation. No postoperative edema was noted. The wounds healed satisfactorily without scarring. No sign of recurrence was found following operation. Conclusion. The CO2 laser has the advantages of requiring only one course, precise tumor removal, a relatively bloodless surgical field, a short operation time, and less or no postoperative pain and edema. Postoperative wound care is convenient and easy with hydrocolloid and alginate dressings. The patient's quality of life is less adversely affected. The CO2 laser may be appropriate for multiple CCAs, giant CCA, CCA overlying or near joints, CCA refractory to cryotherapy, patients on anticoagulants, and those who cannot tolerate pain from cryotherapy, especially children and the elderly. [source]

Pilonidal Sinus Disease Treated by Depilation Using an 800 nm Diode Laser and Review of the Literature

DERMATOLOGIC SURGERY, Issue 5 2005
Anthony V. Benedetto DO, FACP
background. Pilonidal sinus disease is a debilitating, disfiguring chronic ailment that is often resistant to therapy. Its etiology and treatment remain in question. objective. To assess the efficacy of an 800 nm diode laser in the treatment of recalcitrant pilonidal sinus disease. methods. Two patients with recalcitrant pilonidal sinus disease were treated in the lower back, buttocks, and perigluteal cleft area with an 800 nm diode laser with a spot size of 9 × 9 mm, fluences of 30 to 48 J/cm2, and pulse widths of 15 to 24 milliseconds. results. Long-term relief of pilonidal sinus disease was produced with as few as two treatments 2 months apart to as many as six treatments over a 2-year period. With each successive treatment, fewer pulses were needed and the interval between treatments increased. conclusion. The 800 nm diode laser may be an effective tool in the treatment of pilonidal sinus disease. By eliminating the source of hair and hair fragments that course along the surface of the lower back and buttocks, interruption of the etiologic source for pilonidal sinus disease can be accomplished. [source]

Collagen Remodeling After 585-nm Pulsed Dye Laser Irradiation: An Ultrasonographic Analysis

DERMATOLOGIC SURGERY, Issue 10 2003
Brent R. Moody MD
Background and Objectives. Nonablative dermal remodeling is an evolving technology that has generated great interest among both laser surgeons and patients. Evidence indicates that dermal collagen formation is the key mechanism of action for the nonablative techniques. We studied, with ultrasound, new collagen formation after nonablative laser irradiation. Methods. Ten patients with facial rhytids underwent a single treatment with a 585-nm pulsed dye laser. The patients were all female, ranging in age from 47 to 67, and were Fitzpatrick skin types I,III. Laser parameters were as follows: an energy fluence of 2.4 to 3.0 J/cm2, a pulse duration of 350 ,sec, and a spot size of 5 mm with no overlap. Ultrasonographic assessments of dermal collagen were taken at baseline and at 30 and 90 days after treatment. Results. Ultrasonography demonstrated an increase in dermal collagen after a single treatment with the 585-nm pulsed dye laser. The greatest degree of neocollagenesis occurred periocularly. Conclusion. A single treatment with a 585-nm pulsed dye laser appears to increase dermal collagen. This increase in dermal collagen can be assessed with noninvasive cutaneous ultrasound. [source]

Treatment of Facial Telangiectasia With Variable-Pulse High-Fluence Pulsed-Dye Laser: Comparison of Efficacy with Fluences Immediately Above and Below the Purpura Threshold

DERMATOLOGIC SURGERY, Issue 7 2003
Murad Alam MD
Background. Pulsed-dye laser treatment has been shown to be highly effective for the treatment of facial telangiectasia. Posttreatment purpura after such treatment has limited patient acceptance of the procedure. Objective. To determine whether purpura-free treatment with recently introduced variable-pulsed pulsed-dye lasers can effectively reduce facial telangiectasia. Methods. This was a prospective, randomized, controlled, nonblinded trial. Eleven patients received variable-pulse pulsed-dye laser treatment with and without induction of purpura. Telangiectasia were graded on a "telangiectasia density scale," on which a 1 signified extremely fine, sparsely distributed telangiectasia, and 5 referred to thick, ropelike telangiectasia covering the affected area. For each subject, two areas on either side of the facial midline with equivalent telangiectasia density ratings were randomized to the purpura and purpura-free treatment groups, respectively. All treatments used a 7-mm spot size and a 10-ms pulse duration. The fluence associated with the purpura threshold for each patient was determined in test areas. Purpura-free treatment entailed a fluence 1.0 J/cm2 less than the purpura threshold, and purpura-level treatment entailed a fluence 0.5 J/cm2 greater than the threshold. Results. Six weeks after a single purpura-free treatment, mean telangiectasia ratings were reduced from 2.7 to 2.4. Purpura-level treatments resulted in a decrease to 1.4 from the same baseline. Thicker, denser telangiectasia appeared to benefit more from purpura-level treatment (a mean telangiectasia density scale reduction of 1.7) than finer, sparser telangiectasia (a mean reduction of 0.8). In 81% of cases, both investigators and patients rated the side treated with purpura as undergoing a greater reduction in telangiectasia density. Conclusion. Although facial telangiectasia do improve after a single purpura-free treatment with the variable-pulse pulsed-dye laser, they improve more after purpura is induced. Purpura-free and purpura-level treatments may be close to equivalent for treating fine telangiectasia, but purpura-level treatments have a distinct advantage for treating thicker telangiectasia. Significantly, the variable-pulse pulsed-dye laser offers patients the option of effective treatment of some telangiectasia without bruising. [source]

585-nm Pulsed Dye Laser in the Treatment of Surgical Scars Starting on the Suture Removal Day

DERMATOLOGIC SURGERY, Issue 1 2003
Keyvan Nouri MD
Background The optimal time frame to improve the quality and cosmetic appearance of scars by laser therapy has not been clearly elucidated by prior controlled clinical trials. Objective To determine the efficacy of the 585-nm pulsed dye laser (PDL) in the treatment of surgical scars starting on the day of suture removal. Methods Eleven patients (skin types I,IV) with 12 postoperative linear scars that were greater than 2 cm were treated three times on monthly intervals with the 585-nm PDL (450 ,s, 10-mm spot size, 3.5 J/cm2 with 10% overlap) on one scar half, whereas the other half received no treatment. Scars were later evaluated by a blinded examiner using the Vancouver Scar Scale (VSS) for pigmentation, vascularity, pliability, and height. Scars were then blindly examined for cosmetic appearance using a visual analog scale. Results One month after the last treatment, final scar analysis by the blinded examiner revealed a significant difference between treated and untreated sites, with the treated halves scoring better in all scar parameters in the VSS and in cosmetic appearance. The treated halves demonstrated an overall average improvement in the VSS between the first treatment score and the final score of 54% versus 10% in the controls (P=0.0002). The cosmetic appearance score (0=worst; 10=best) at final assessment was significantly better for the treated scars, scoring 7.3 versus the averaged control score of 5.2 (P=0.016). Conclusion The 585-nm PDL is effective and safe in improving the quality and cosmetic appearance of surgical scars in skin types I,IV starting on the day of suture removal. [source]

Treatment of Pigmented Hypertrophic Scars with the 585 nm Pulsed Dye Laser and the 532 nm Frequency-Doubled Nd:YAG Laser in the Q-Switched and Variable Pulse Modes: A Comparative Study

DERMATOLOGIC SURGERY, Issue 8 2002
Leyda Elizabeth Bowes MD
background. Pigmented hypertrophic scars are a difficult condition to treat. They may result from traumatic injuries or from surgical and cosmetic procedures. The 585 nm flashlamp-pumped pulsed dye laser (FLPDL) has been used to treat this condition, with significant improvement of varying degrees. It remains to be determined whether other laser modalities may have a similar or even greater success in the treatment of pigmented hypertrophic scars. objective. To determine the efficacy of the 532 nm frequency-doubled Nd:YAG laser in the treatment of pigmented hypertrophic scars as compared to the 585 nm FLPDL. methods. Six patients with pigmented hypertrophic scars and skin phototypes II,IV were chosen. A scar was selected for treatment in each patient and divided into four equal 2 cm segments. Three segments were each treated with a different laser modality and one was left untreated to serve as the control. A 585 nm FLPDL was used with an energy of 3.5 J, a pulse duration of 450 ,sec, and a 10 mm spot size. A 532 nm Q-switched frequency-doubled Nd:YAG laser was set to an energy of 2.8 J, a 10-nsec pulse, and a 3 mm spot size. The same 532 nm laser was set to the variable pulse mode to treat a 2 cm scar segment, with an energy of 9.5 J, a 10-msec pulse, and a 4 mm spot size. An average of 3.3 treatments were performed on each scar segment, at intervals of 4,6 weeks and long-term follow-up at 22 weeks. Treatment outcome was graded by a blind observer using the Vancouver General Hospital (VGH) Burn Scar Assessment Scale. A SigmaStat t -test was used to determine the statistical significance of the values obtained. results. Treatment of pigmented hypertrophic scars with the 532 nm Q-switched Nd:YAG laser led to a significant improvement of 38% in the VGH scores when compared to baseline (P = .005). The 585 nm FLPDL also had a favorable effect on the scars, with an average improvement of 36.1% in the VGH scores. There was no significant difference noted between the outcome of treatment with either of these two lasers. Treatment with the 532 nm variable pulse Nd:YAG laser led to a 19% improvement in the VGH scores of scars, which did not differ significantly from the 16.1% improvement observed in control scars on the last follow-up visit. No side effects or complications from treatment were noted or reported during the course of the study. At the conclusion of the study, five of six patients chose the segment treated with the 532 nm Q-switched Nd:YAG laser as the best segment overall. conclusion. The 532 nm Q-switched Nd:YAG laser and the 585 nm FLPDL offer comparable favorable results in the treatment of pigmented hypertrophic scars. The 532 nm Q-switched Nd:YAG laser may be preferred by patients particularly distressed by the dark color of their scars. [source]

Treatment of Port-Wine Stain Birthmarks Using the 1.5-msec Pulsed Dye Laser at High Fluences in Conjunction with Cryogen Spray Cooling

DERMATOLOGIC SURGERY, Issue 4 2002
Kristen M. Kelly MD
Background. The majority of port-wine stain (PWS) patients treated with the pulsed dye laser (PDL) do not achieve complete blanching. Safe administration of higher fluences has been proposed as a means of improving treatment efficacy. Objective. To determine the safety and efficacy of PWS treatment with the 1.5-msec PDL at high fluences in conjunction with cryogen spray cooling. Methods. Twenty PWS patients were treated with the PDL in combination with cryogen spray cooling utilizing a 7 or 10 mm spot size and fluences ranging from 6 to 15 J/cm2. Before and after treatment photographs were compared on a blinded basis. Results. No scarring or skin textural changes occurred. Blanching scores were as follows: 20% of patients achieved 75% or greater blanching after an average of 3.3 treatments, 30% achieved 50,74% blanching, 20% achieved 25,49% blanching, and 30% achieved less than 25% blanching. Conclusion. In conjunction with cryogen spray cooling, the PDL can be safely used at high fluences. At this time it is not clear that the use of higher fluences improves treatment efficacy; however, as other aspects of PWS laser treatment are optimized, safe administration of higher fluences is likely to be advantageous. [source]

Minocycline-Induced Hyperpigmentation of the Tongue: Successful Treatment with the Q-Switched Ruby Laser

DERMATOLOGIC SURGERY, Issue 3 2002
Ilyse S. Friedman MD
background. Minocycline-induced hyperpigmentation (MIH) is a benign condition that may persist for years despite abrogation of therapy. The Q-switched ruby laser (QSRL) has been successful in removing such lesions from the skin. To date there is no documentation of QSRL or any laser being used to treat lingual hyperpigmentation associated with minocycline therapy. objective. Long-term follow-up results are reported for the use of QSRL to treat lingual hyperpigmentation. The literature is reviewed comparing the use of different laser systems on MIH. methods. A 26-year-old woman with pigment changes of the tongue and buccal mucosa due to long-term minocycline therapy was treated with four consecutive sessions with QSRL (694 nm, 20-nsec pulse duration, and 6.5 mm spot size) at 3.6,4.0 J/cm2. results. A 90% resolution was achieved after three treatments. After the final treatment the lesions were completely gone. There were no side effects reported. No new pigment was detected at follow-up. conclusion. Treatment with the QSRL is a safe and effective strategy for treating hyperpigmentation of the tongue associated with minocycline therapy. [source]

Laser Hair Removal: Long-Term Results with a 755 nm Alexandrite Laser

Laser Hair Removal with Alexandrite versus Diode Laser Using Four Treatment Sessions: 1-Year Results

DERMATOLOGIC SURGERY, Issue 11 2001
Sorin Eremia MD
Background. Laser hair removal is the treatment of choice for hypertrichosis. The two most commonly used hair removal lasers are compared. Objective. To present the results of a comparative study examining the role of wavelength, fluence, spot size, pulse width, and cooling systems on long-term results after a series of four laser hair removal treatments using the 755 nm alexandrite and 800,810 nm diode lasers. Methods. The axillae of 15 untanned, type I,V patients were treated side by side four times at 4- to 6-week intervals with a 755 nm, 3-msec pulse width, cryogen spray-equipped alexandrite laser and an 800 nm, variable pulse width, cooled sapphire window-equipped diode laser. Each patient was pretested and treated with the maximum fluence tolerated at the largest spot size available for each laser (12 mm round/113 mm2 for the alexandrite and 9 mm for the diode). Results. Evaluations were done at 3, 6, 9, and 12 months after the last treatment. Twelve-month results with the alexandrite and diode lasers achieved 85% versus 84% hair reduction. The fact that tan avoidance was strictly followed permitted the use of relatively high fluences (25,30+ J/cm2) even in type IV patients. For most patients, four treatment sessions using high fluences (30,40 J/cm2) with relatively large spot sizes (12 mm round for the 755 nm alexandrite and 9 mm for the 800 nm diode) resulted in 12-month hair reductions in the 90% range. Conclusion. Both the alexandrite and diode lasers in this 12-month study produced excellent long-term hair reductions. [source]

Application of High Spatial Resolution Laser Ablation ICP-MS to Crystal-Melt Trace Element Partition Coefficient Determination

GEOSTANDARDS & GEOANALYTICAL RESEARCH, Issue 1 2007
Maurizio Petrelli
ICP-MS; ablation laser; éléments en trace; figure de mérite; coefficients de partage entre cristal et liquide In this contribution we evaluate the capabilities of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) using a 12 ,m spot size. Precision, accuracy and detection limits were assessed on the USGS BCR-2G reference material. We demonstrate that the 12 ,m LA-ICP-MS analyses of experimentally-grown amphibole and garnet are in excellent agreement with secondary ion mass spectrometry (SIMS) trace element determinations on the same crystals. The 12 ,m spot size configuration was subsequently used to determine trace element crystal-melt partition coefficients (Dc/m) for a wide range of trace elements in amphibole in equilibrium with a basanitic melt. The following strategy to determine accurately and evaluate Dc/m is proposed. One or more major elements determined previously by electron probe microanalysis (EPMA) was used to ensure consistency between EPMA and the composition of the aerosol produced by the laser ablation. Measured Dc/m values were successively evaluated using the lattice strain model. The use of this strategy significantly improved the precision and accuracy of Dc/m determination when a LA-ICP-MS configuration with a high spatial resolution was employed. Dans cet article nous évaluons les potentialités de l'ablation laser couplée à un spectromètre de masse à plasma induit (LA-ICP-MS) en travaillant avec un diamètre d'impact de 12 ,m. Précision, justesse et limites de détections sont évaluées sur le matériau de référence BCR-2G de l'USGS. Nous démontrons que les analyses LA-ICP-MS faites avec un diamètre de 12 ,m sur les amphiboles et des grenats synthétiques sont en excellent accord avec les déterminations d'éléments en trace effectuées sur les mêmes cristaux par sonde ionique (SIMS). Ce diamètre d'impact de 12 ,m a donc été sélectionné pour déterminer les coefficients de partage cristal/liquide (Dc/m) pour un grand nombre d'éléments en trace dans une amphibole en équilibre avec un liquide basanitique. Nous proposons la stratégie d'analyse suivante, qui assure une détermination exacte des coefficients de partage Dc/m. Un ou plusieurs des éléments majeurs déterminés auparavant par microsonde électronique (EMPA) est utilisé pour garantir la consistance des données entre EMPA et la composition de l'aérosol produit par l'ablation laser. Les Dc/m mesurés sont ensuite évalués en utilisant le modèle de contrainte de réseau. L'utilisation de cette stratégie améliore de manière significative la précision et la justesse des déterminations de Dc/m quand elle est couplée à l'utilisation d'un système LA-ICP-MS de grande résolution spatiale. [source]

Sharp Carbon-Nanotube Tips and Carbon-Nanotube Soldering Irons,

ADVANCED MATERIALS, Issue 22 2009
Abha Misra
The nano-electron beam assisted fabrication of atomically sharp iron-based tips (see figure) and the creation of a nano-soldering iron for nano-interconnects using Fe-filled multiwalled carbon nanotubes (MWCNTs) is reported. The technique allows carving of a MWCNT and a control of the flow of the encapsulated metal outward by regulating the e-beam exposure time and spot size. [source]

Hair removal using an 800-nm Diode Laser: Comparison at different treatment intervals of 45, 60, and 90 days

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 1 2005
Navid Bouzari MD
Background, Some laser irradiation parameters such as wavelength, fluence, pulse duration, and spot size have been shown to influence the damage of any target inside the skin, however, the role of some patients' factors such as hair growth cycle is still under debate. Objective, To determine the association of treatment interval and laser treatment outcome. Methods, In a retrospective chart review of 176 patients undergoing laser-assisted hair removal with a diode laser 24 patients were selected. All accepted to cease the therapy, and be followed-up for 5 months. At the end of the study the patients were questioned about the efficacy of the treatment as well as the adverse effects. Hair counting was also performed. The adverse effects (pain, blister or erosion, hyperpigmentation, hypopigmentation, and folliculitis) were questioned during the follow-up period. Results, The mean hair reduction was 78.1%, 45.8%, and 28.7% in 45, 60, and 90-day interval groups, respectively (P < 0.0001). Conclusion, The treatment interval was related to the treatment outcome in our study. [source]

POWTEX , the high-intensity time-of-flight diffractometer at FRM II for structure analysis of polycrystalline materials

JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 5 2008
Harald Conrad
In order to provide the large chemistry and materials science as well as the geosciences communities with a powerful tool for rapid data acquisition, a time-of-flight powder diffractometer to be installed at the new Munich reactor has been designed. The time-of-flight technique is expected to outperform a monochromator instrument by at least an order of magnitude in data acquisition time, particularly on small samples of less than a cubic centimetre. The construction of this innovative type of diffractometer utilizes modern components such as focusing super-mirror neutron guides, a four-unit high-speed disk chopper system and linear position-sensitive detectors covering a solid angle of about 2, steradian. The diffractometer design enables an easy enlargement of the focal spot size and is therefore equally well suited for the texture analysis of large geological and archaeological samples. [source]

Focusing capillary optics for use in solution small-angle X-ray scattering

JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 1 2007
Jessica S. Lamb
Measurements of the global conformation of macromolecules can be carried out using small-angle X-ray scattering (SAXS). Glass focusing capillaries, manufactured at the Cornell High Energy Synchrotron Source (CHESS), have been successfully employed for SAXS measurements on the heme protein cytochrome c. These capillaries provide high X-ray flux into a spot size of tens of micrometres, permitting short exposures of small-volume samples. Such a capability is ideal for use in conjunction with microfluidic mixers, where time resolution may be determined by beam size and sample volumes are kept small to facilitate mixing and conserve material. [source]

Treatment of linear and spider telangiectasia with an intense pulsed light source

JOURNAL OF COSMETIC DERMATOLOGY, Issue 4 2004
R A Retamar
Summary Background, The flashlamp-pumped pulsed dye laser (585 and 577 nm) has proved to be an effective and safe treatment option in the therapy of linear and spider facial telangiectasia. Nevertheless, the postoperative purpura, which most patients see as cosmetically disfiguring, has always been a matter of concern. Aims, To test the effectiveness and safety of an intense pulsed light source (IPLS), which emits non-coherent light adjustable within the 515,1200 nm range, in the treatment of linear and spider facial telangiectasia. Patients & Methods, One hundred and forty patients with linear and stellate facial telangiectasia were treated with an IPLS. Results, In 94 (67.1%) the results were considered excellent (clearance of 80,100%), 43 (30.7%) showed good results (clearance of 40,80%) and in 3 patients (2.1%) the results were poor (clearance < 40%). Post-treatment side effects were minimal and well tolerated. There were no instances of scarring or other permanent side effects. Owing to the large spot size, a large area could be treated within one session. No anaesthesia was required. Conclusion, IPLS is a highly effective and comparably safe therapeutic alternative to the pulsed dye laser in the treatment of facial telangiectasia. The rate of cosmetically relevant side effects is considerably smaller, patient compliance is excellent and the method can easily be applied in an outpatient setting. [source]

Simulation of an aperture in the thick metallic screen that gives high intensity and small spot size using surface plasmon polariton

JOURNAL OF MICROSCOPY, Issue 3 2003
K. Tanaka
Summary The optical wave behaviour around a subwavelength aperture in a thick metallic screen is examined through three-dimensional computer simulation. Treating the metallic screen as a dielectric slab with complex-valued permittivity, it is possible to design an aperture that simultaneously provides high intensity and small spot size through the excitation of surface plasmon polaritons on the side walls of the aperture. [source]

Spatial resolution limits for synchrotron-based spectromicroscopy in the mid- and near-infrared

JOURNAL OF SYNCHROTRON RADIATION, Issue 4 2008
Erika Levenson
Spatial resolution tests were performed on beamline 1.4.4 at the Advanced Light Source in Berkeley, CA, USA, a third-generation synchrotron light source. This beamline couples the high-brightness synchrotron source to a Thermo-Electron Continuµm XL infrared microscope. Two types of resolution tests were performed in both the mid-IR and near-IR. The results are compared with a diffraction-limited spot size theory. At shorter near-IR wavelengths the experimental results begin to deviate from diffraction-limited so a combined diffraction-limit and electron-beam-source-size model is employed. This description shows how the physical electron beam size of the synchrotron source begins to dominate the focused spot size at higher energies. The transition from diffraction-limited to electron-beam-size-limited performance is a function of storage-ring parameters and the optical demagnification within the beamline and microscope optics. The discussion includes how different facilities, beamlines and microscopes will affect the achievable spatial resolution. As synchrotron light sources and other next-generation accelerators such as energy-recovery LINACs and free-electron lasers achieve smaller beam emittances, beta-functions and/or energy spreads, diffraction-limited performance can continue to higher-energy beams, perhaps ultimately into the extreme ultraviolet. [source]

Suite of three protein crystallography beamlines with single superconducting bend magnet as the source

JOURNAL OF SYNCHROTRON RADIATION, Issue 6 2004
Alastair A. MacDowell
At the Advanced Light Source, three protein crystallography beamlines have been built that use as a source one of the three 6,T single-pole superconducting bending magnets (superbends) that were recently installed in the ring. The use of such single-pole superconducting bend magnets enables the development of a hard X-ray program on a relatively low-energy 1.9,GeV ring without taking up insertion-device straight sections. The source is of relatively low power but, owing to the small electron beam emittance, it has high brightness. X-ray optics are required to preserve the brightness and to match the illumination requirements for protein crystallography. This was achieved by means of a collimating premirror bent to a plane parabola, a double-crystal monochromator followed by a toroidal mirror that focuses in the horizontal direction with a 2:1 demagnification. This optical arrangement partially balances aberrations from the collimating and toroidal mirrors such that a tight focused spot size is achieved. The optical properties of the beamline are an excellent match to those required by the small protein crystals that are typically measured. The design and performance of these new beamlines are described. [source]

Beamline 10.3.2 at ALS: a hard X-ray microprobe for environmental and materials sciences

JOURNAL OF SYNCHROTRON RADIATION, Issue 3 2004
Matthew A. Marcus
Beamline 10.3.2 at the ALS is a bend-magnet line designed mostly for work on environmental problems involving heavy-metal speciation and location. It offers a unique combination of X-ray fluorescence mapping, X-ray microspectroscopy and micro-X-ray diffraction. The optics allow the user to trade spot size for flux in a size range of 5,17,µm in an energy range of 3,17,keV. The focusing uses a Kirkpatrick,Baez mirror pair to image a variable-size virtual source onto the sample. Thus, the user can reduce the effective size of the source, thereby reducing the spot size on the sample, at the cost of flux. This decoupling from the actual source also allows for some independence from source motion. The X-ray fluorescence mapping is performed with a continuously scanning stage which avoids the time overhead incurred by step-and-repeat mapping schemes. The special features of this beamline are described, and some scientific results shown. [source]

The effect of 595,nm pulsed dye laser on superficial and nodular basal cell carcinomas

LASERS IN SURGERY AND MEDICINE, Issue 6 2009
Sonali M. Shah MD
Abstract Background and Objective Basal cell carcinomas (BCCs) have supporting vasculature that could serve as a target for 595,nm pulsed dye laser (PDL). The objective of this study was to determine the effect of repeated PDL treatments on BCCs of superficial and nodular subtypes and of varying diameters. Study Design/Materials and Methods Twenty biopsy-proven BCCs received four 595,nm PDL treatments at 2-week intervals. The tumor and 4,mm of peripheral skin were treated using a set of previously optimized laser parameters: one pass, 15,J/cm2 energy, 3,ms pulse length, no cooling, and 7,mm spot size with 10% overlap. The treated area was excised and evaluated histologically for residual tumor. Histologic response rates of the PDL treated BCCs were compared with that of non-PDL treated, matched control tumors. Results Nearly all BCCs <1.5,cm in diameter (n,=,12) showed complete response to four PDL treatments (91.7%; n,=,11/12) versus 16.7% of controls (n,=,2/12, P -value,= 0.0003). BCCs ,1.5,cm in diameter (n,=,8) showed a complete response rate of 25% (n,=,2/8) versus 0% of controls (n,=,0/8, P -value,=,0.2). Mean clinical tumor diameter of the complete responders was 1.1,cm (n,=,13) versus 2.2,cm (n,=,7) for incomplete responders (P -value,=,0.005). Tumor histologic types among the complete responders included superficial, nodular, micronodular, and keratinizing. Incompletely responding BCCs showed a significant reduction in tumor burden after PDL treatment, with residual histologic tumor burden ranging from <1% to 29% of the original clinical tumor diameter, compared to 13,68% residual tumor burden for the corresponding controls (P -value,=,0.05). Conclusions PDL is an effective means of reducing tumor burden in patients with large BCCs and may be an alternative therapy in BCCs <1.5,cm in diameter. Lasers Surg. Med. 41:417,422, 2009. © 2009 Wiley-Liss, Inc. [source]

Pilot study examining the combined use of pulsed dye laser and topical Imiquimod versus laser alone for treatment of port wine stain birthmarks

LASERS IN SURGERY AND MEDICINE, Issue 9 2008
Cheng-Jen Chang MD
Abstract Background and Objective The objective of this study was to improve port wine stain (PWS) therapeutic outcome in response to laser therapy. Our specific aim was to determine whether the combined use of pulsed dye laser (PDL) therapy and topical Imiquimod versus PDL alone can improve PWS therapeutic outcome. Study Design/Materials and Methods This pilot study involved a retrospective review of 20 subjects, all Asian, with PWS. Subject ages ranged between 3 and 56 years. Upon enrollment, three test sites were prospectively identified on each subject for treatment assignments to the following regimens: (A) PDL+Imiquimod; (B) PDL alone; and (C) Imiquimod alone. PDL test sites received a single treatment with a 585 nm wavelength; 1.5 milliseconds pulse duration; spot size 7 mm using a light dosage of 10 J/cm2 with cryogen spray cooling. For the PDL+Imiquimod and Imiquimod alone test sites, subjects were instructed to apply Imiquimod topically to the sites once daily for 1 month after PDL exposure. Subjects were followed-up at 1, 3, 6, and 12 months after PDL exposure to evaluate each of the three test sites. The primary efficacy measurement was the quantitative assessment of blanching responses as measured by a DermoSpectrometer to calculate the hemoglobin-index of each site at 1, 3, 6, and 12 months after PDL exposure. Subjects were also closely monitored for any adverse effects. Results Based on paired sample test analysis, there were clinically, and statistically significant, differences in blanching responses over time favoring PWS receiving PDL+Imiquimod as compared to either PDL or Imiquimod alone (P<0.05). At 12 months, it should be noted that there was some evidence of redarkening of PWS test sites treated by PDL+Imiquimod and PDL alone, presumably due to revascularization of blood vessels. However, based on comparison of the hemoglobin-indices determined at 1 and 12 months after PDL exposure, there was less revascularization of PWS test sites treated with PDL+Imiquimod as compared to PDL alone (P<0.05). Transient hyperpigmentation was noted in 10% (n,=,2) and 40% (n,=,8) of subjects on the PDL+Imiquimod and PDL alone test sites, respectively. On all sites, hyperpigmentation resolved spontaneously without medical intervention within 6 months. Permanent hypopigmentation or scarring was not observed on any test site. Conclusion Based on the results of this pilot study, PDL+Imiquimod resulted in superior blanching responses over time as compared to PDL alone for treatment of test sites on PWS lesions. Although the PDL+Imiquimod approach is intriguing, clinical validation in large PWS patient samples is required. Lesers Surg. Med. 40:605,610, 2008. © 2008 Wiley-Liss, Inc. [source]

Ex vivo histological characterization of a novel ablative fractional resurfacing device,

LASERS IN SURGERY AND MEDICINE, Issue 2 2007
Basil M. Hantash MD
Abstract Background and Objectives We introduce a novel CO2 laser device that utilizes ablative fractional resurfacing for deep dermal tissue removal and characterize the resultant thermal effects in skin. Study Design/Materials and Methods A prototype 30 W, 10.6 µm CO2 laser was focused to a 1/e2 spot size of 120 µm and pulse duration up to 0.7 milliseconds to achieve a microarray pattern in ex vivo human skin. Lesion depth and width were assessed histologically using either hematoxylin & eosin (H&E) or lactate dehyrdogenase (LDH) stain. Pulse energies were varied to determine their effect on lesion dimensions. Results Microarrays of ablative and thermal injury were created in fresh ex vivo human skin irradiated with the prototype CO2 laser device. Zones of tissue ablation were surrounded by areas of tissue coagulation spanning the epidermis and part of the dermis. A thin condensed lining on the interior wall of the lesion cavity was observed consistent with eschar formation. At 23.3 mJ, the lesion width was approximately 350 µm and depth 1 mm. In this configuration, the cavities were spaced approximately 500 µm apart and interlesional epidermis and dermis demonstrated viable tissue by LDH staining. Conclusion A novel prototype ablative CO2 laser device operating in a fractional mode was developed and its resultant thermal effects in human abdominal tissue were characterized. We discovered that controlled microarray patterns could be deposited in skin with variable depths of dermal tissue ablation depending on the treatment pulse energy. This is the first report to characterize the successful use of ablative fractional resurfacing as a potential approach to dermatological treatment. Lasers Surg. Med. 39:87,95, 2007. © 2007 Wiley-Liss, Inc. [source]