Clinical evaluation of the SmartSkin fractional laser for the treatment of photodamage and acne scars.

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Gold, Michael H; Heath, Amanda D; Biron, Julie A

2009-11-01

Fractional photothermolysis with a CO2 laser shows promise in the treatment of photodamaged skin. The purpose of this study was to evaluate a fractional CO2 laser device (SmartSkin, Cynosure, Westford, MA) for the treatment of facial photodamage. Twelve subjects seeking treatment of facial hyperpigmentation, skin laxity, wrinkles and fine lines, enlarged pores and acne scars enrolled in the study. Each subject was treated twice with the SmartSkin device at three- to five-week intervals. Results were evaluated at one week, one month and three months after the final treatment. All 12 subjects completed the study. Physician and subject assessments both indicated that clinical improvements in all photodamage parameters were apparent at one month and persisted at least three months. Improvements in acne scars were noted but not graded. Eleven subjects would recommend the treatment to family and friends. The median pain scores during the initial and final treatments were 2.00 and 2.00, respectively, on a scale of 0-5. Only one adverse effect, facial edema, was judged "probably related to treatment." The SmartSkin fractional laser device improves photodamaged skin for at least three months. The treatment was well tolerated and adverse effects were limited to transient facial edema.

Fractional CO 2 laser resurfacing as monotherapy in the treatment of atrophic facial acne scars

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Imran Majid

2014-01-01

Full Text Available Background: While laser resurfacing remains the most effective treatment option for atrophic acne scars, the high incidence of post-treatment adverse effects limits its use. Fractional laser photothermolysis attempts to overcome these limitations of laser resurfacing by creating microscopic zones of injury to the dermis with skip areas in between. Aim: The aim of the present study is to assess the efficacy and safety of fractional CO 2 laser resurfacing in atrophic facial acne scars. Materials and Methods: Sixty patients with moderate to severe atrophic facial acne scars were treated with 3-4 sessions of fractional CO 2 laser resurfacing at 6-week intervals. The therapeutic response to treatment was assessed at each follow up visit and then finally 6 months after the last laser session using a quartile grading scale. Response to treatment was labelled as ′excellent′ if there was >50% improvement in scar appearance and texture of skin on the grading scale while 25-50% response and <25% improvement were labelled as ′good′ and ′poor′ response, respectively. The overall satisfaction of the patients and any adverse reactions to the treatment were also noted. Results: Most of the patients showed a combination of different morphological types of acne scars. At the time of final assessment 6 months after the last laser session, an excellent response was observed in 26 patients (43.3% while 15 (25% and 19 patients (31.7% demonstrated a good and poor response respectively. Rolling and superficial boxcar scars responded the best while pitted scars responded the least to fractional laser monotherapy. The commonest reported adverse effect was transient erythema and crusting lasting for an average of 3-4 and 4-6 days, respectively while three patients developed post-inflammatory pigmentation lasting for 8-12 weeks. Conclusions: Fractional laser resurfacing as monotherapy is effective in treating acne scars especially rolling and superficial boxcar

Ablative skin resurfacing with a novel microablative CO2 laser.

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Gotkin, Robert H; Sarnoff, Deborah S; Cannarozzo, Giovanni; Sadick, Neil S; Alexiades-Armenakas, Macrene

2009-02-01

Carbon dioxide (CO2) laser skin resurfacing has been a mainstay of facial rejuvenation since its introduction in the mid 1990s. Recently, a new generation of fractional or microablative CO2 lasers has been introduced to the marketplace. According to the concept of fractional photothermolysis, these lasers ablate only a fraction of the epidermal and dermal architecture in the treatment area. An array of microscopic thermal wounds is created that ablates the epidermis and dermis within very tiny zones; adjacent to these areas, the epidermis and dermis are spared. This microablative process of laser skin resurfacing has proven safe and effective not only for facial rejuvenation, but elsewhere on the body as well. It is capable of improving wrinkles, acne scars, and other types of atrophic scars and benign pigmented lesions associated with elastotic, sun-damaged skin. Because of the areas of spared epidermis and dermis inherent in a procedure that employs fractional photothermolysis, healing is more rapid compared to fully ablative CO2 laser skin resurfacing and downtime is proportionately reduced. A series of 32 consecutive patients underwent a single laser resurfacing procedure with the a new microablative CO2 laser. All patients were followed for a minimum of 6 months and were asked to complete patient satisfaction questionnaires; a 6 month postoperative photographic evaluation by an independent physician, not involved in the treatment, was also performed. Both sets of data were graded and reported on a quartile scale. Results demonstrated greater than 50% improvement in almost all patients with those undergoing treatment for wrinkles, epidermal pigment or solar elastosis deriving the greatest change for the better (>75%).

Efficacy and safety of Erbium-doped Yttrium Aluminium Garnet fractional resurfacing laser for treatment of facial acne scars

Directory of Open Access Journals (Sweden)

Balakrishnan Nirmal

2013-01-01

Full Text Available Background: Treatment of acne scars with ablative fractional laser resurfacing has given good improvement. But, data on Indian skin are limited. A study comparing qualitative, quantitative, and subjective assessments is also lacking. Aim: Our aim was to assess the improvement of facial acne scars with Erbium-doped Yttrium Aluminium Garnet (Er:YAG 2940 nm fractional laser resurfacing and its adverse effects in 25 patients at a tertiary care teaching hospital. Methods: All 25 patients received four treatment sessions with Er:YAG fractional laser at 1-month interval. The laser parameters were kept constant for each of the four sittings in all patients. Qualitative and quantitative assessments were done using Goodman and Barron grading. Subjective assessment in percentage of improvement was also documented 1 month after each session. Photographs were taken before each treatment session and 1 month after the final session. Two unbiased dermatologists performed independent clinical assessments by comparing the photographs. The kappa statistics was used to monitor the agreement between the dermatologists and patients. Results: Most patients (96% showed atleast fair improvement. Rolling and superficial box scars showed higher significant improvement when compared with ice pick and deep box scars. Patient′s satisfaction of improvement was higher when compared to physician′s observations. No serious adverse effects were noted with exacerbation of acne lesions forming the majority. Conclusion: Ablative fractional photothermolysis is both effective and safe treatment for atrophic acne scars in Indian skin.Precise evaluation of acne scar treatment can be done by taking consistent digital photographs.

Histologic effects of resurfacing lasers.

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Freedman, Joshua R; Greene, Ryan M; Green, Jeremy B

2014-02-01

By utilizing resurfacing lasers, physicians can significantly improve the appearance of sun-damaged skin, scars, and more. The carbon dioxide and erbium:yttrium-aluminum-garnet lasers were the first ablative resurfacing lasers to offer impressive results although these earlier treatments were associated with significant downtime. Later, nonablative resurfacing lasers such as the neodymium:yttrium-aluminum-garnet laser proved effective, after a series of treatments with less downtime, but with more modest results. The theory of fractional photothermolysis has revolutionized resurfacing laser technology by increasing the safety profile of the devices while delivering clinical efficacy. A review of the histologic and molecular consequences of the resurfacing laser-tissue interaction allows for a better understanding of the devices and their clinical effects. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Selective Photothermolysis to target Sebaceous Glands: Theoretical Estimation of Parameters and Preliminary Results Using a Free Electron Laser

Energy Technology Data Exchange (ETDEWEB)

Fernanda Sakamoto, Apostolos Doukas, William Farinelli, Zeina Tannous, Michelle D. Shinn, Stephen Benson, Gwyn P. Williams, H. Dylla, Richard Anderson

2011-12-01

The success of permanent laser hair removal suggests that selective photothermolysis (SP) of sebaceous glands, another part of hair follicles, may also have merit. About 30% of sebum consists of fats with copious CH2 bond content. SP was studied in vitro, using free electron laser (FEL) pulses at an infrared CH2 vibrational absorption wavelength band. Absorption spectra of natural and artificially prepared sebum were measured from 200 nm to 3000 nm, to determine wavelengths potentially able to target sebaceous glands. The Jefferson National Accelerator superconducting FEL was used to measure photothermal excitation of aqueous gels, artificial sebum, pig skin, human scalp and forehead skin (sebaceous sites). In vitro skin samples were exposed to FEL pulses from 1620 to 1720 nm, spot diameter 7-9.5 mm with exposure through a cold 4C sapphire window in contact with the skin. Exposed and control tissue samples were stained using H and E, and nitroblue tetrazolium chloride staining (NBTC) was used to detect thermal denaturation. Natural and artificial sebum both had absorption peaks near 1210, 1728, 1760, 2306 and 2346 nm. Laser-induced heating of artificial sebum was approximately twice that of water at 1710 and 1720 nm, and about 1.5x higher in human sebaceous glands than in water. Thermal camera imaging showed transient focal heating near sebaceous hair follicles. Histologically, skin samples exposed to {approx}1700 nm, {approx}100-125 ms pulses showed evidence of selective thermal damage to sebaceous glands. Sebaceous glands were positive for NBTC staining, without evidence of selective loss in samples exposed to the laser. Epidermis was undamaged in all samples. Conclusions: SP of sebaceous glands appears to be feasible. Potentially, optical pulses at {approx}1720 nm or {approx}1210 nm delivered with large beam diameter and appropriate skin cooling in approximately 0.1 s may provide an alternative treatment for acne.

Fraxel laser indications and long-term follow-up.

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Tanzi, Elizabeth L; Wanitphakdeedecha, Rungsima; Alster, Tina S

2008-01-01

Fractional photothermolysis, based on creating spatially precise microscopic thermal wounds, is performed using a 1550-nm erbium fiber laser that targets water-containing tissue to effect the photocoagulation of narrow, sharply defined columns of skin known as microscopic thermal zones. According to the authors, Fraxel resurfacing has been shown to be both safe and effective for facial and nonfacial photodamage, atrophic acne scars, hypopigmented scars, and dyspigmentation. Because only a fraction of the skin is treated during a single session, a series (typically 3 to 6 treatments) of fractional resurfacing at 2- to 4-week intervals is required for the best clinical improvement. It is the authors' experience that a series of Fraxel treatments can achieve a similar clinical result for atrophic scars compared with traditional ablative laser skin resurfacing. However, the improvement seen after a series of Fraxel treatments for perioral laxity and rhytides often falls short of the impressive results that can be achieved with ablative laser skin resurfacing.

Fractional laser skin resurfacing.

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Alexiades-Armenakas, Macrene R; Dover, Jeffrey S; Arndt, Kenneth A

2012-11-01

Laser skin resurfacing (LSR) has evolved over the past 2 decades from traditional ablative to fractional nonablative and fractional ablative resurfacing. Traditional ablative LSR was highly effective in reducing rhytides, photoaging, and acne scarring but was associated with significant side effects and complications. In contrast, nonablative LSR was very safe but failed to deliver consistent clinical improvement. Fractional LSR has achieved the middle ground; it combined the efficacy of traditional LSR with the safety of nonablative modalities. The first fractional laser was a nonablative erbium-doped yttrium aluminum garnet (Er:YAG) laser that produced microscopic columns of thermal injury in the epidermis and upper dermis. Heralding an entirely new concept of laser energy delivery, it delivered the laser beam in microarrays. It resulted in microscopic columns of treated tissue and intervening areas of untreated skin, which yielded rapid reepithelialization. Fractional delivery was quickly applied to ablative wavelengths such as carbon dioxide, Er:YAG, and yttrium scandium gallium garnet (2,790 nm), providing more significant clinical outcomes. Adjustable laser parameters, including power, pitch, dwell time, and spot density, allowed for precise determination of percent surface area, affected penetration depth, and clinical recovery time and efficacy. Fractional LSR has been a significant advance to the laser field, striking the balance between safety and efficacy.

Fractional resurfacing in the Asian patient: Current state of the art.

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Wat, Heidi; Wu, Douglas C; Chan, Henry Hin Lee

2017-01-01

Fractionated photothermolysis (FP) has revolutionized modern laser technology. By creating selective columns of microthermal damage, fractionated devices allows for greater treatment depths to be achieved without the prolonged downtime and risk of complications seen in traditional fully ablative laser resurfacing. Fractional resurfacing is a proven method to treat a variety of cutaneous conditions. In the Caucasian patient, a wide range of devices and treatment settings can be utilized safely and effectively. However, ethnic skin requires special consideration due to its unique pigmentary characteristics and clinical presentations. In this review article, we detail the current indications and strategies to optimize results and mitigate complications when utilizing fractional resurfacing for the Asian patient. A review of the MEDLINE English literature was conducted on fractionated laser devices studied in the Asian population. Articles included describe non-ablative devices including fractionated erbium glass, thulium fiber, diode, and radiofrequency devices; and ablative devices including fractionated carbon dioxide (CO 2 ) laser, erbium yttrium aluminum garnet and yttrium scandium gallium garnet (YSGG) laser. These data were integrated with the expert opinion of the authors. Taking into account the unique characteristics and cosmetic concerns of the Asian population, fractional resurfacing can be considered a safe and effective option for the treatment of atrophic and hypertrophic scarring, and photorejuvenation in ethnic skin types. Select cases of melasma may be treated with fractionated non-ablative devices, but utilized with caution. The predominant complication associated with fractional resurfacing for these conditions is post-inflammatory hyperpigmentation (PIH) and rebound worsening of melasma. A greater number of treatments at lower density settings and wider treatment intervals typically produce the lowest risks of PIH without compromising treatment

Theranostic probe for simultaneous in vivo photoacoustic imaging and confined photothermolysis by pulsed laser at 1064 nm in 4T1 breast cancer model

Science.gov (United States)

Zhou, Min; Ku, Geng; Pageon, Laura; Li, Chun

2014-11-01

Here, we report that polyethylene glycol (PEG)-coated copper(ii) sulfide nanoparticles (PEG-CuS NPs) with their peak absorption tuned to 1064 nm could be used both as a contrast agent for photoacoustic tomographic imaging of mouse tumor vasculature and as a mediator for confined photothermolysis of tumor cells in an orthotopic syngeneic 4T1 breast tumor model. PEG-CuS NPs showed stronger photoacoustic signal than hollow gold nanospheres and single-wall carbon nanotubes at 1064 nm. MicroPET imaging of 4T1 tumor-bearing mice showed a gradual accumulation of the NPs in the tumor over time. About 6.5% of injected dose were taken up in each gram of tumor tissue at 24 h after intravenous injection of 64Cu-labeled PEG-CuS NPs. For both photoacoustic imaging and therapeutic studies, nanosecond (ns)-pulsed laser was delivered with Q-switched Nd:YAG at a wavelength of 1064 nm. Unlike conventional photothermal ablation therapy mediated by continuous wave laser with which heat could spread to the surrounding normal tissue, interaction of CuS NPs with short pulsed laser deliver heat rapidly to the treatment volume keeping the thermal damage confined to the target tissues. Our data demonstrated that it is possible to use a single-compartment nanoplatform to achieve both photoacoustic tomography and highly selective tumor destruction at 1064 nm in small animals.Here, we report that polyethylene glycol (PEG)-coated copper(ii) sulfide nanoparticles (PEG-CuS NPs) with their peak absorption tuned to 1064 nm could be used both as a contrast agent for photoacoustic tomographic imaging of mouse tumor vasculature and as a mediator for confined photothermolysis of tumor cells in an orthotopic syngeneic 4T1 breast tumor model. PEG-CuS NPs showed stronger photoacoustic signal than hollow gold nanospheres and single-wall carbon nanotubes at 1064 nm. MicroPET imaging of 4T1 tumor-bearing mice showed a gradual accumulation of the NPs in the tumor over time. About 6.5% of injected dose were

Possibility of increasing the efficiency of laser-induced tattoo removal by optical skin clearing

International Nuclear Information System (INIS)

Genina, E A; Bashkatov, A N; Tuchin, V V; Yaroslavskii, I V; Altshuler, G B

2008-01-01

The possibility of selective laser photothermolysis improvement for the removal of tattoo pigments due to the optical clearing of human skin is investigated. It is shown experimentally that the optical skin clearing increases the tattoo image contrast. Computer Monte Carlo simulations show that by decreasing the laser beam scattering in upper skin layers, it is possible to reduce the radiation power required for tattoo removal by 30%-40% and, therefore, to increase the the photothermolysis efficiency. (special issue devoted to application of laser technologies in biophotonics and biomedical studies)

Possibility of increasing the efficiency of laser-induced tattoo removal by optical skin clearing

Science.gov (United States)

Genina, E. A.; Bashkatov, A. N.; Tuchin, V. V.; Altshuler, G. B.; Yaroslavskii, I. V.

2008-06-01

The possibility of selective laser photothermolysis improvement for the removal of tattoo pigments due to the optical clearing of human skin is investigated. It is shown experimentally that the optical skin clearing increases the tattoo image contrast. Computer Monte Carlo simulations show that by decreasing the laser beam scattering in upper skin layers, it is possible to reduce the radiation power required for tattoo removal by 30%—40% and, therefore, to increase the the photothermolysis efficiency.

Current Status of Fractional Laser Resurfacing.

Science.gov (United States)

Carniol, Paul J; Hamilton, Mark M; Carniol, Eric T

2015-01-01

Fractional lasers were first developed based on observations of lasers designed for hair transplantation. In 2007, ablative fractional laser resurfacing was introduced. The fractionation allowed deeper tissue penetration, leading to greater tissue contraction, collagen production and tissue remodeling. Since then, fractional erbium:YAG resurfacing lasers have also been introduced. These lasers have yielded excellent results in treating photoaging, acne scarring, and dyschromia. With the adjustment of microspot density, pulse duration, number of passes, and fluence, the surgeon can adjust the treatment effects. These lasers have allowed surgeons to treat patients with higher Fitzpatrick skin types (types IV to VI) and greater individualize treatments to various facial subunits. Immunohistochemical analysis has demonstrated remodeling effects of the tissues for several months, producing longer lasting results. Adjuvant treatments are also under investigation, including concomitant face-lift, product deposition, and platelet-rich plasma. Finally, there is a short recovery time from treatment with these lasers, allowing patients to resume regular activities more quickly. Although there is a relatively high safety profile for ablative fractionated lasers, surgeons should be aware of the limitations of specific treatments and the associated risks and complications.

Ablative Fractional 10 600 nm Carbon Dioxide Laser Versus Non-ablative Fractional 1540 nm Erbium-Glass Laser in Egyptian Post-acne Scar patients.

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Elsaie, Mohamed L; Ibrahim, Shady M; Saudi, Wael

2018-01-01

Introduction: Non-ablative fractional erbium-doped glass 1540 nm and fractional ablative 10600 nm carbon dioxide lasers are regarded as effective modalities for treating acne atrophic scars. In this study, we aimed to compare the effectiveness of fractional CO 2 laser and fractional nonablative 1540 nm erbium doped glass laser in treating post acne atrophic scars in Egyptian patients. Methods: Fifty-eight patients complaining of moderate and severe acne atrophic scars were randomly divided into 2 groups of 29 patients each. Both groups were subjected to 4 treatment sessions with 3 weeks interval and were followed up for 3 months. In group A, enrolled patient sreceived C2 laser, while in group B, patients were treated with 1540 nm erbium glass fractional laser. Results: Clinical assessment revealed that the mean grades of progress and improvement were higher with fractional 10600 nm CO2 laser but with non-significant difference between both treatments ( P = 0.1). The overall patients' satisfaction with both lasers were not significantly different ( P = 0.44). Conclusion: Both fractional ablative CO2 and fractional non-ablative erbium glass lasers are good modalities for treating acne scars with a high efficacy and safety profile and good patient satisfaction. The fractional ablative laser showed higher efficacy while non-ablative laser offered less pain and shorter downtime.

Fractional laser exposure induces neutrophil infiltration (N1 phenotype into the tumor and stimulates systemic anti-tumor immune response.

Directory of Open Access Journals (Sweden)

Masayoshi Kawakubo

Full Text Available Ablative fractional photothermolysis (aFP using a CO2 laser generates multiple small diameter tissue lesions within the irradiation field. aFP is commonly used for a wide variety of dermatological indications, including treatment of photodamaged skin and dyschromia, drug delivery and modification of scars due to acne, surgical procedures and burns. In this study we explore the utility of aFP for treating oncological indications, including induction of local tumor regression and inducing anti-tumor immunity, which is in marked contrast to current indications of aFP.We used a fractional CO2 laser to treat a tumor established by BALB/c colon carcinoma cell line (CT26.CL25, which expressed a tumor antigen, beta-galactosidase (beta-gal. aFP treated tumors grew significantly slower as compared to untreated controls. Complete remission after a single aFP treatment was observed in 47% of the mice. All survival mice from the tumor inoculation rejected re-inoculation of the CT26.CL25 colon carcinoma cells and moreover 80% of the survival mice rejected CT26 wild type colon carcinoma cells, which are parental cells of CT26.CL25 cells. Histologic section of the FP-treated tumors showed infiltrating neutrophil in the tumor early after aFP treatment. Flow cytometric analysis of tumor-infiltrating lymphocytes showed aFP treatment abrogated the increase in regulatory T lymphocyte (Treg, which suppresses anti-tumor immunity and elicited the expansion of epitope-specific CD8+ T lymphocytes, which were required to mediate the tumor-suppressing effect of aFP.We have demonstrated that aFP is able to induce a systemic anti-tumor adaptive immunity preventing tumor recurrence in a murine colon carcinoma in a mouse model. This study demonstrates a potential role of aFP treatments in oncology and further studies should be performed.

Efficacy of fractional lasers in treating alopecia: a literature review.

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Perper, Marina; Aldahan, Adam S; Fayne, Rachel A; Emerson, Christopher P; Nouri, Keyvan

2017-11-01

Hair loss stemming from different types of alopecia, such as androgenic alopecia and alopecia areata, negatively affects over half the population and, in many circumstances, causes serious psychosocial distress. Current treatment options for alopecia, such as minoxidil, anthralin, and intralesional corticosteroids, vary efficacy and side effect profiles. It is known that low-level laser/light therapies (LLLT), or photobiomodulations, such as the US FDA-cleared HairMax Lasercomb®, He-Ne laser, and excimer laser, are relatively affordable, user-friendly, safe, and effective forms of treatment for hair loss. While less is known about the effectiveness of fractional lasers for combating hair loss, research suggests that by creating microscopic thermal injury zones, fractional lasers may cause an increase in hair growth from a wound healing process, making them potential therapeutic options for alopecia. A literature review was performed to evaluate the effectiveness of fractional lasers on hair regrowth. The specific fractional laser therapies include the 1550-nm nonablative fractional erbium-glass laser, the ablative fractional 2940-nm erbium:YAG laser, and the ablative fractional CO 2 fractional laser. Additional randomized controlled trials are necessary to further evaluate the effectiveness of the lasers, as well as to establish appropriate parameters and treatment intervals.

Laser systems for ablative fractional resurfacing

DEFF Research Database (Denmark)

Paasch, Uwe; Haedersdal, Merete

2011-01-01

of a variety of skin conditions, primarily chronically photodamaged skin, but also acne and burn scars. In addition, it is anticipated that AFR can be utilized in the laser-assisted delivery of topical drugs. Clinical efficacy coupled with minimal downtime has driven the development of various fractional...... ablative laser systems. Fractionated CO(2) (10,600-nm), erbium yttrium aluminum garnet, 2940-nm and yttrium scandium gallium garnet, 2790-nm lasers are available. In this article, we present an overview of AFR technology, devices and histopathology, and we summarize the current clinical possibilities...

Laser systems for ablative fractional resurfacing

DEFF Research Database (Denmark)

Paasch, Uwe; Haedersdal, Merete

2011-01-01

ablative laser systems. Fractionated CO(2) (10,600-nm), erbium yttrium aluminum garnet, 2940-nm and yttrium scandium gallium garnet, 2790-nm lasers are available. In this article, we present an overview of AFR technology, devices and histopathology, and we summarize the current clinical possibilities...... of a variety of skin conditions, primarily chronically photodamaged skin, but also acne and burn scars. In addition, it is anticipated that AFR can be utilized in the laser-assisted delivery of topical drugs. Clinical efficacy coupled with minimal downtime has driven the development of various fractional...

Fractional laser-assisted drug delivery

DEFF Research Database (Denmark)

Taudorf, Elisabeth Hjardem; Lerche, C.M.; Erlendsson, A M

2016-01-01

BACKGROUND AND OBJECTIVE: Ablative fractional laser (AFXL) facilitates delivery of topical methotrexate (MTX). This study investigates impact of laser-channel depth on topical MTX-delivery. MATERIALS AND METHODS: MTX (1% [w/v]) diffused for 21 hours through AFXL-exposed porcine skin in in vitro F...

Fractional ablative laser skin resurfacing: a review.

Science.gov (United States)

Tajirian, Ani L; Tarijian, Ani L; Goldberg, David J

2011-12-01

Ablative laser technology has been in use for many years now. The large side effect profile however has limited its use. Fractional ablative technology is a newer development which combines a lesser side effect profile along with similar efficacy. In this paper we review fractional ablative laser skin resurfacing.

Fractional laser-assisted drug uptake

DEFF Research Database (Denmark)

Banzhaf, Christina A; Thaysen-Petersen, Daniel; Bay, Christiane

2017-01-01

BACKGROUND AND OBJECTIVE: Ablative fractional laser (AFXL) is acknowledged to increase uptake of topically applied agents in skin. AFXL channels gradually close over time, which may impair this capability. The time frame for applying a drug after AFXL exposure remains to be established. The aim...... in laser-exposed and non-laser-exposed skin at 24-48 hours. CONCLUSIONS: The time frame to maintain enhanced drug delivery sustained for several hours after AFXL exposure, corresponding to channel morphology and loss of skin integrity. Lasers Surg. Med. 49:348-354, 2017. © 2016 Wiley Periodicals, Inc....

Fractional laser-assisted drug delivery

DEFF Research Database (Denmark)

Erlendsson, Andrés M; Doukas, Apostolos G; Farinelli, William A

2016-01-01

BACKGROUND AND OBJECTIVE: Ablative fractional laser (AFXL) is rapidly evolving as one of the foremost techniques for cutaneous drug delivery. While AFXL has effectively improved topical drug-induced clearance rates of actinic keratosis, treatment of basal cell carcinomas (BCCs) has been challenging......, potentially due to insufficient drug uptake in deeper skin layers. This study sought to investigate a standardized method to actively fill laser-generated channels by altering pressure, vacuum, and pressure (PVP), enquiring its effect on (i) relative filling of individual laser channels; (ii) cutaneous...

The spectrum of laser skin resurfacing: nonablative, fractional, and ablative laser resurfacing.

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Alexiades-Armenakas, Macrene R; Dover, Jeffrey S; Arndt, Kenneth A

2008-05-01

The drive to attain cosmetic facial enhancement with minimal risk and rapid recovery has inspired the field of nonsurgical skin rejuvenation. Laser resurfacing was introduced in the 1980s with continuous wave carbon dioxide (CO(2)) lasers; however, because of a high rate of side effects, including scarring, short-pulse, high-peak power, and rapidly scanned, focused-beam CO(2) lasers and normal-mode erbium-doped yttrium aluminium garnet lasers were developed, which remove skin in a precisely controlled manner. The prolonged 2-week recovery time and small but significant complication risk prompted the development of non-ablative and, more recently, fractional resurfacing in order to minimize risk and shorten recovery times. Nonablative resurfacing produces dermal thermal injury to improve rhytides and photodamage while preserving the epidermis. Fractional resurfacing thermally ablates microscopic columns of epidermal and dermal tissue in regularly spaced arrays over a fraction of the skin surface. This intermediate approach increases efficacy as compared to nonablative resurfacing, but with faster recovery as compared to ablative resurfacing. Neither nonablative nor fractional resurfacing produces results comparable to ablative laser skin resurfacing, but both have become much more popular than the latter because the risks of treatment are limited in the face of acceptable improvement. At the completion of this learning activity, participants should be familiar with the spectrum of lasers and light technologies available for skin resurfacing, published studies of safety and efficacy, indications, methodologies, side effects, complications, and management.

Parameters in fractional laser assisted delivery of topical anesthetics: Role of laser type and laser settings.

Science.gov (United States)

Meesters, Arne A; Nieboer, Marilin J; Kezic, Sanja; de Rie, Menno A; Wolkerstorfer, Albert

2018-05-07

Efficacy of topical anesthetics can be enhanced by pretreatment of the skin with ablative fractional lasers. However, little is known about the role of parameters such as laser modality and laser density settings in this technique. Aims of this study were to compare the efficacy of pretreatment with two different ablative fractional laser modalities, a CO 2 laser and an Er:YAG laser, and to assess the role of laser density in ablative fractional laser assisted topical anesthesia. In each of 15 healthy subjects, four 10 × 10 mm test regions on the back were randomized to pretreatment (70-75 μm ablation depth) with CO 2 laser at 5% density, CO 2 laser at 15% density, Er:YAG laser at 5% density or Er:YAG laser at 15% density. Articaine hydrochloride 40 mg/ml + epinephrine 10 μg/ml solution was applied under occlusion to all four test regions. After 15 minutes, a pass with the CO 2 laser (1,500 μm ablation depth) was administered as pain stimulus to each test region. A reference pain stimulus was given on unanesthetized skin. The main outcome parameter, pain, was scored on a 0-10 visual analogue scale (VAS) after each pain stimulus. Median VAS scores were 1.50 [CO 2 5%], 0.50 [CO 2 15%], 1.50 [Er:YAG 5%], 0.43 [Er:YAG 15%], and 4.50 [unanesthetized reference]. VAS scores for all pretreated test regions were significantly lower compared to the untreated reference region (P laser pretreated regions. However, VAS scores were significantly lower at 15% density compared to 5% density for both for the CO 2 laser (P laser (P laser was considered slightly more painful than pretreatment with Er:YAG laser by the subjects. Fractional laser assisted topical anesthesia is effective even with very low energy settings and an occlusion time of only 15 minutes. Both the CO 2 laser and the Er:YAG laser can be used to assist topical anesthesia although the CO 2 laser pretreatment is experienced as more painful. In our study settings, using articaine

Transcutaneous drug delivery by liposomes using fractional laser technology.

Science.gov (United States)

Fujimoto, Takahiro; Wang, Jian; Baba, Kazuki; Oki, Yuka; Hiruta, Yuki; Ito, Masayuki; Ito, Shinobu; Kanazawa, Hideko

2017-07-01

Transdermal delivery of hydrophilic peptides remains a challenge due to their poor cellular uptake and transdermal penetration. We hypothesize that combination of a CO 2 fractional laser to enhance percutaneous absorption and liposomes as transdermal carriers would improve skin penetration of hydrophilic drugs. NA. Liposomes were prepared using membrane fusion lipid dioleoylphosphatidylethanolamine, and used to deliver 5-carboxyfluorescein (CF) and fluorescein isothiocyanate-conjugated ovalbumin (OVA-FITC) as model hydrophilic peptide drugs. Liposome size was estimated by dynamic light scattering. Liposome uptake into murine macrophage cells and penetration or permeation into Yucatan micropig skin after irradiation by CO 2 fractional laser at varying energy levels (laser power and exposure duration) were investigated using Franz cell and fluorescence microscopy. Oxidative damage to the irradiated mouse skin was assessed by electron spin resonance. Size of CF and OVA-FITC encapsulated liposomes was 324 ± 75 nm. Cellular uptake of OVA-FITC delivered by liposomes was 10-fold higher (1,370 relative fluorescence units, RFU) than delivered in solution form (130 RFU). Fractional laser irradiation increased skin permeation rate of CF liposomes (0-10%) and OVA-FITC liposomes (4-40%) in a dose-dependent manner. Although peeling off the stratum corneum facilitated CF liposome penetration at low energy levels (2.69-3.29 J/cm 2 ; 10-20 W for 500 μs), drug permeation was similar (7-8%) in peeled or untreated skin at higher laser energy levels (6.06 J/cm 2 ; 20 W for 1,500 μs). FITC penetrated deeper in the skin after laser irradiation. However, OH, O2-, and VC reactive oxygen species were generated upon irradiation of the skin with a fractional CO 2 laser. Increasing laser power and irradiation, time increased liposome uptake by cells and penetration of peptide drugs across the skin in a dose-dependent manner. High-energy CO 2 fractional laser overcomes the

Fractional CO2 laser treatment for vaginal laxity: A preclinical study.

Science.gov (United States)

Kwon, Tae-Rin; Kim, Jong Hwan; Seok, Joon; Kim, Jae Min; Bak, Dong-Ho; Choi, Mi-Ji; Mun, Seok Kyun; Kim, Chan Woong; Ahn, Seungwon; Kim, Beom Joon

2018-05-07

Various studies have investigated treatment for vaginal laxity with microablative fractional carbon dioxide CO 2 laser in humans; however, this treatment has not yet been studied in an animal model. Herein, we evaluate the therapeutic effects of fractional CO 2 laser for tissue remodeling of vaginal mucosa using a porcine model, with the aim of improving vaginal laxity. The fractional CO 2 laser enables minimally invasive and non-incisional procedures. By precisely controlling the laser energy pulses, energy is sent to the vaginal canal and the introitus area to induce thermal denaturation and contraction of collagen. We examined the effects of fractional CO 2 laser on a porcine model via clinical observation and ultrasound measurement. Also, thermal lesions were histologically examined via hematoxylin-eosin staining, Masson's trichrome staining, and Elastica van Gieson staining and immunohistochemistry. The three treatment groups, which were determined according to the amount of laser-energy applied (60, 90, and 120 mJ), showed slight thermal denaturation in the vaginal mucosa, but no abnormal reactions, such as excessive hemorrhaging, vesicles, or erythema, were observed. Histologically, we also confirmed that the denatured lamina propria induced by fractional CO 2 laser was dose-dependently increased after laser treatment. The treatment groups also showed an increase in collagen and elastic fibers due to neocollagenesis and angiogenesis, and the vaginal walls became firmer and tighter because of increased capillary and vessel formation. Also, use of the fractional CO 2 laser increased HSP (heat shock protein) 70 and collagen type I synthesis. Our results show that microablative fractional CO 2 laser can produce remodeling of the vaginal connective tissue without causing damage to surrounding tissue, and the process of mucosa remodeling while under wound dressings enables collagen to increase and the vaginal wall to become thick and tightened. Lasers Surg. Med

Fractional laser-assisted delivery of methyl aminolevulinate

DEFF Research Database (Denmark)

Haak, Christina S; Farinelli, William A; Tam, Joshua

2012-01-01

Pretreatment of skin with ablative fractional lasers (AFXL) enhances the uptake of topical photosensitizers used in photodynamic therapy (PDT). Distribution of photosensitizer into skin layers may depend on depth of laser channels and incubation time. This study evaluates whether depth of intrade...

Laser tattoo removal with preceding ablative fractional treatment

Science.gov (United States)

Cencič, Boris; Možina, Janez; Jezeršek, Matija

2013-06-01

A combined laser tattoo removal treatment, first the ablative fractional resurfacing (AFR) with an Er:YAG laser and then the q-switched (QSW) Nd:YAG laser treatment, was studied. Experiments show that significantly higher fluences can be used for the same tissue damage levels.

Fractional lasers in dermatology - Current status and recommendations

Directory of Open Access Journals (Sweden)

Apratim Goel

2011-01-01

Full Text Available Introduction: Fractional laser technology is a new emerging technology to improve scars, fine lines, dyspigmentation, striae and wrinkles. The technique is easy, safe to use and has been used effectively for several clinical and cosmetic indications in Indian skin. Devices: Different fractional laser machines, with different wavelengths, both ablative and non-ablative, are now available in India. A detailed understanding of the device being used is recommended. Indications: Common indications include resurfacing for acne, chickenpox and surgical scars, periorbital and perioral wrinkles, photoageing changes, facial dyschromias. The use of fractional lasers in stretch marks, melasma and other pigmentary conditions, dermatological conditions such as granuloma annulare has been reported. But further data are needed before adopting them for routine use in such conditions. Physician qualification: Any qualified dermatologist may administer fractional laser treatment. He/ she should possess a Master′s degree or diploma in dermatology and should have had specific hands-on training in lasers, either during postgraduation or later at a facility which routinely performs laser procedures under a competent dermatologist or plastic surgeon with experience and training in using lasers. Since parameters may vary with different systems, specific training tailored towards the concerned device at either the manufacturer′s facility or at another center using the machine is recommended. Facility: Fractional lasers can be used in the dermatologist′s minor procedure room for the above indications. Preoperative counseling and Informed consent: Detailed counseling with respect to the treatment, desired effects and possible postoperative complications should be provided to the patient. The patient should be provided brochures to study and also adequate opportunity to seek information. A detailed consent form needs to be completed by the patient. Consent form should

Fractional CO2 laser resurfacing for atrophic acne scars

DEFF Research Database (Denmark)

Hedelund, Lene; Haak, Christina Skovbølling; Togsverd-Bo, Katrine

2012-01-01

The treatment of acne scars with fractional CO(2) lasers is gaining increasing impact, but has so far not been compared side-by-side to untreated control skin.......The treatment of acne scars with fractional CO(2) lasers is gaining increasing impact, but has so far not been compared side-by-side to untreated control skin....

Fractionated laser resurfacing corrects the inappropriate UVB response in geriatric skin.

Science.gov (United States)

Spandau, Dan F; Lewis, Davina A; Somani, Ally-Khan; Travers, Jeffrey B

2012-06-01

Non-melanoma skin cancer is a disease primarily afflicting geriatric patients as evidenced by the fact that 80% of all non-melanoma skin cancers are diagnosed in patients over the age of 60 years. As such, geriatric skin responds to cancer-inducing UVB irradiation in a manner that allows the establishment of tumor cells. Currently, the only effective treatment for non-melanoma skin cancer is the removal of the tumors after they appear, indicating the need for a more cost-effective prophylactic therapy. Geriatric volunteers were treated with fractionated laser resurfacing therapy on either sun-protected (upper buttocks) or chronically sun-exposed (dorsal forearm) skin. Fractionated laser resurfacing therapy was shown to decrease the occurrence of senescent fibroblasts in geriatric dermis, increase the dermal expression of IGF-1, and correct the inappropriate UVB response observed in untreated geriatric skin. These responses to fractionated laser resurfacing were equal to the effects seen previously using the more aggressive wounding following dermabrasion. Furthermore, fractionated laser resurfacing was equally effective in both sun-protected and sun-exposed skin. The ability of fractionated laser resurfacing treatment to protect against the occurrence of UVB-damaged proliferating keratinocytes indicates the potential of fractionated laser resurfacing to reduce or prevent aging-associated non-melanoma skin cancer.

Ablative fractional laser enhances MAL-induced PpIX accumulation

DEFF Research Database (Denmark)

Haak, C S; Christiansen, K; Erlendsson, Andrés M

2016-01-01

BACKGROUND AND OBJECTIVES: Pretreatment of skin with ablative fractional laser enhances accumulation of topical provided photosensitizer, but essential information is lacking on the interaction between laser channel densities and pharmacokinetics. Hence our objectives were to investigate how...... (range 46-133min) induced fluorescence levels similar to curettage and 180min incubation. Furthermore, MAL 80 and 160mg/g induced similar fluorescence intensities in skin exposed to laser densities of 1, 2 and 5% (p>0.0537, 30-180min). CONCLUSION: MAL-induced protoporphyrin accumulation is augmented...... protoporphyrin accumulation was affected by laser densities, incubation time and drug concentration. METHODS: We conducted the study on the back of healthy male volunteers (n=11). Test areas were pretreated with 2940nm ablative fractional Er:YAG laser, 11.2mJ per laser channel using densities of 1, 2, 5, 10...

Translational medicine in the field of ablative fractional laser (AFXL)-assisted drug delivery

DEFF Research Database (Denmark)

Haedersdal, Merete; Erlendsson, Andrés M; Paasch, Uwe

2016-01-01

Ablative fractional lasers enhance uptake of topical therapeutics and the concept of fractional laser-assisted drug delivery has now been taken into clinical practice. Objectives We systematically reviewed preclinical data and clinical evidence for fractional lasers to enhance drug uptake...... level of evidence was reached for actinic keratoses treated with methylaminolevulinate for photodynamic therapy (level IB, 5 randomized controlled trials), substantiating superior and long-lasting efficacy versus conventional photodynamic therapy. No adverse events were reported, but ablative fractional...... laser-assisted drug delivery implies risks of systemic drug absorption, especially when performed over large skin areas. Conclusions Fractional laser-assisted drug delivery is beneficial in enhancing preclinical and clinical outcomes for certain skin conditions....

Fractional ablative erbium YAG laser

DEFF Research Database (Denmark)

Taudorf, Elisabeth H; Haak, Christina S; Erlendsson, Andrés M

2014-01-01

laser parameters with tissue effects. MATERIALS AND METHODS: Ex vivo pig skin was exposed to a miniaturized 2,940 nm AFXL, spot size 225 µm, density 5%, power levels 1.15-2.22 W, pulse durations 50-225 microseconds, pulse repetition rates 100-500 Hz, and 2, 20, or 50 stacked pulses, resulting in pulse......BACKGROUND AND OBJECTIVES: Treatment of a variety of skin disorders with ablative fractional lasers (AFXL) is driving the development of portable AFXLs. This study measures micropore dimensions produced by a small 2,940 nm AFXL using a variety of stacked pulses, and determines a model correlating...... 190 to 347 µm. CONCLUSIONS: Pulse stacking with a small, low power 2,940 nm AFXL created reproducible shallow to deep micropores, and influenced micropore configuration. Mathematical modeling established relations between laser settings and micropore dimensions, which assists in choosing laser...

Significant skin-tightening by closure of fractional ablative laser holes.

Science.gov (United States)

Russe, Elisabeth; Purschke, Martin; Limpiangkanan, Wikunda; Farinelli, William A; Wang, Ying; Doukas, Apostolos G; Sakamoto, Fernanda H; Wechselberger, Gottfried; Anderson, Richard Rox

2018-01-01

Ablative fractional laser treatment uses thousands of very small laser beam wounds to damage a fraction of the skin, which stimulates tissue remodeling. Each open micro-wound heals without scarring, but the amount of skin tightening achieved is limited. This animal study was performed to test the hypothesis that immediate temporary closure of fractional laser wounds could increase skin tightening after fractional ablative laser treatment. Four adult swine were used for the study; 98 square test sites (3 × 3 cm) were tattooed on the abdomen and flanks of each pig. An ablative fractional Erbium:YAG laser (Sciton Profile, Sciton Inc, Palo Alto, CA) was used to treat the test areas. A laser micro-spot fluence of 375 J/cm 2 was delivered in 150-250 microseconds pulses, resulting in an array of ablation channels extending 1.5 mm deep into the skin, with a spot size of 250 µm, with 10% treatment density. Immediately following laser exposure the resulting holes were closed using a stretched elastic adhesive dressing, which, when applied, recoiled and compressed the diameter of the ablation holes. The compressive dressings were removed after 7 days. This procedure was compared to removing the same amount of skin (10%) mechanically by specially designed 19 gauge coring needles, as well as to the same laser and coring methods without compression closure. Area and shape of test sites were measured by digital photography before and 28 days after treatment. Data analysis included compensation for animal growth, as measured by increase in the area of the untreated control sites. All treated and control sites healed within a week, without scarring evident at 28 days. Laser treatment combined with compressive wound closure caused significant shrinkage at 28 days compared with untreated control sites. The treated skin area was reduced by 11.5% (P = 0.0001). Needle coring with wound closure produced similar, significant shrinkage (8%, P < 0.0021), whereas laser

Non-ablative fractional laser provides long-term improvement of mature burn scars

DEFF Research Database (Denmark)

Taudorf, Elisabeth H; Danielsen, Patricia L; Paulsen, Ida F

2015-01-01

BACKGROUND AND OBJECTIVES: Non-ablative fractional laser-treatment is evolving for burn scars. The objective of this study was to evaluate clinical and histological long-term outcome of 1,540 nm fractional Erbium: Glass laser, targeting superficial, and deep components of mature burn scars....... MATERIALS & METHODS: Side-by-side scar-areas were randomized to untreated control or three monthly non-ablative fractional laser-treatments using superficial and extra-deep handpieces. Patient follow-up were at 1, 3, and 6 months. Primary outcome was improvement in overall scar-appearance on a modified...... of scar-appearance. CONCLUSIONS: Combined superficial and deep non-ablative fractional laser-treatments induce long-term clinical and histological improvement of mature burn scars....

Efficiency of Carbon Dioxide Fractional Laser in Skin Resurfacing.

Science.gov (United States)

Petrov, Andrej

2016-06-15

The aim of the study was to confirm the efficiency and safety of the fractional CO2 laser in skin renewal and to check the possibility of having a synergistic effect in patients who besides carbon dioxide laser are treated with PRP (platelet-rich plasma) too. The first group (Examined Group 1 or EG1) included 107 patients treated with fractional CO2 laser (Lutronic eCO2) as mono-therapy. The second group (Control Group or CG) covered 100 patients treated with neither laser nor plasma in the same period but subjected to local therapy with drugs or other physio-procedures under the existing protocols for treatment of certain diseases. The third group (Examined Group 2 or EG2) treated 25 patients with combined therapy of CO2 laser and PRP in the treatment of facial rejuvenation or treatment of acne scars. Patient's satisfaction, in general, is significantly greater in both examined groups (EG1 and EG2) (p skin is significant (χ2 = 39.41; df = 4; p skin was significantly lower in examined group (treated with laser), p = 0.0002. Multifunctional fractional carbon dioxide laser used in treatment of patients with acne and pigmentation from acne, as well as in the treatment of scars from different backgrounds, is an effective and safe method that causes statistically significant better effect of the treatment, greater patients' satisfaction, minimal side effects and statistically better response to the therapy, according to assessments by the patient and the therapist.

Nonablative fractional laser resurfacing in Asian skin--a review.

Science.gov (United States)

Sachdeva, Silonie

2010-12-01

Skin resurfacing has been a part of cosmetic dermatology for more than two decades now, and most of it has been ablative with traditional aggressive lasers including the CO(2) and erbium. The last few years have seen a revolutionary change with the invention of nonablative lasers for skin tightening. Fractional resurfacing is a new concept of cutaneous remodeling whereby laser-induced zones of microthermal injury are surrounded by normal untreated tissue that helps in quicker healing. The various wavelengths used are 1320, 1440, and 2940 nm with depth of penetration ranging from 25 μ to 1.2 mm. This article reviews the history of nonablative fractional laser resurfacing, its indications, contraindications, and a review of use in Asian skin with Fitzpatrick type III-VI. © 2010 Wiley Periodicals, Inc.

Efficacy of long pulse Nd:YAG laser versus fractional Er:YAG laser in the treatment of hand wrinkles.

Science.gov (United States)

Robati, Reza M; Asadi, Elmira; Shafiee, Anoosh; Namazi, Nastaran; Talebi, Atefeh

2018-04-01

There are different modalities for hand rejuvenation. Fractional Er:YAG laser and long pulse Nd:YAG laser were introduced for treating hand wrinkles. We plan to compare fractional Er:YAG laser and long pulse Nd:YAG laser in a randomized controlled double-blind design with multiple sessions and larger sample size in comparison with previous studies. Thirty-three participants with hand wrinkles entered this study. They were randomly allocated to undergo three monthly laser treatments on each hand, one with a fractional Er:YAG laser and the other with a long pulse Nd:YAG laser. The evaluations included assessment of clinical improvement determined by two independent dermatologists not enrolled in the treatment along with measuring skin biomechanical property of hands using a sensitive biometrologic device with the assessment of cutaneous resonance running time (CRRT). Moreover, potential side effects and patients' satisfaction have been documented at baseline, 1 month after each treatment, and 3 months after the final treatment session. Clinical evaluation revealed both modalities significantly reduce hand wrinkles (p value lasers. Mean CRRT values also decreased significantly after the laser treatment compared to those of the baseline in both laser groups. There was no serious persistent side effect after both laser treatments. Both fractional Er:YAG and long pulse Nd:YAG lasers show substantial clinical improvement of hand skin wrinkles with no serious side effects. However, combination treatment by these lasers along with the other modalities such as fat transfer could lead to better outcomes in hand rejuvenation. IRCT2016032020468N4.

Nonablative Fractional Laser Resurfacing in Skin of Color: Evidence-based Review.

Science.gov (United States)

Kaushik, Shivani B; Alexis, Andrew F

2017-06-01

Background: Nonablative laser resurfacing represents one of the major advances in procedural dermatology over the past decade. However, its use in darker skin types is limited by safety concerns and a relative lack of available data. Aim: To provide evidence-based recommendations for the use of fractional lasers in darker skin types. Evidence review: A broad literature search of PubMed/Medline database was conducted in April 2016 using the term fractional lasers. A free text search of keywords including fractional resurfacing, nonablative lasers, skin type, skin of color, ethnic skin, Fitzpatrick skin type, Asian skin, African Americans, Afro-Caribbean, and Hispanics was also executed. An in-depth review of all the relevant articles fitting the authors' inclusion/exclusion criteria was performed. Thereafter, each study was assigned levels of evidence per the Modified Criteria by Oxford Center of Evidence Based Medicine. A recommendation was made for a specific treatment based on the presence of at least one Level 1 study or more than three Level 2 or 3 studies that had concordant results. Findings: The available evidence strongly suggests that fractional lasers are a favorable treatment option for a variety of dermatological diseases in Fitzpatrick skin phototypes IV to VI. Level 1 evidence was found for the use of fractional lasers for treating acne, striae and skin rejuvenation. Level 2 evidence was found for their use in acne scars, melasma, and surgical/traumatic scars. Conclusion: Fractional resurfacing is a safe and efficacious treatment option for various dermatological disorders in darker skin types; however, there is a paucity of high-quality studies involving skin types V and VI.

Generalized eczematous reaction after fractional carbon dioxide laser therapy for tattoo allergy.

Science.gov (United States)

Meesters, Arne A; De Rie, Menno A; Wolkerstorfer, Albert

2016-12-01

Allergic tattoo reactions form a therapeutically difficult entity. Treatment with conventional quality-switched lasers does not completely remove the allergenic particles and may lead to generalized hypersensitivity reactions. Recently, ablative fractional laser therapy was introduced as a treatment for allergic tattoo removal. We present two cases of allergic reactions to red tattoo ink treated with 10,600-nm fractional CO 2 laser. At the end of treatment, almost complete removal of red ink accompanied by a significant reduction of symptoms was observed in the first patient, whereas the second patient developed an acute generalized eczematous reaction after five treatments. These findings confirm that ablative fractional laser therapy is capable of significant removal of tattoo ink in an allergic tattoo reaction. However, it implies a risk of generalized hypersensitivity reactions. To our knowledge, this is the first case of a generalized hypersensitivity reaction following treatment of tattoo allergy with the fractional CO 2 laser.

Laser corrective surgery with fractional carbon dioxide laser following full-thickness skin grafts

OpenAIRE

Emily Forbat; Faisal R Ali; Raj Mallipeddi; Firas Al-Niaimi

2017-01-01

Full-thickness skin grafts (FTSGs) are frequently used to treat patients with burn injuries and to repair defects rendered by excisional (including Mohs) surgery. The evidence for corrective laser surgery after scar formation is well established. With regard to laser treatment of FTSG, the evidence is sparse. Laser treatment after FTSG is a novel concept, with minimal literature. We present a case series, one of the first to our knowledge, of the treatment of FTSG with fractional CO2 laser in...

Fractional CO2 lasers contribute to the treatment of stable non-segmental vitiligo.

Science.gov (United States)

Yuan, Jinping; Chen, Hongqiang; Yan, Ru; Cui, Shaoshan; Li, Yuan-Hong; Wu, Yan; Gao, Xing-Hua; Chen, Hong-Duo

2016-12-01

Stable non-segmental vitiligo is often resistant to conventional therapies. The purpose of this study was to investigate the effect of three types of fractional lasers in the treatment of stable non-segmental vitiligo. Twenty patients were enrolled in the study. The vitiligo lesions of each patient were divided into four treatment parts, and all parts were treated with narrowband ultraviolet-B (NB-UVB). Three of the four parts were respectively treated with three types of fractional lasers (two ablative 10,600-nm CO 2 lasers and one non-ablative 1,565-nm laser), followed by topical betamethasone solution application. The treatment period lasted six months. Efficacy and satisfaction were respectively assessed by dermatologists and patients. The ablative CO 2 lasers, in combination with topical betamethasone solution and NB-UVB, achieved marked to excellent improvement on white patches assessed by dermatologists. Patients showed high satisfaction scores for the treatments. The non-ablative 1,565-nm fractional laser did not provide any further benefit in the treatment of vitiligo. No severe adverse events developed for any of the treatments. The treatment protocol with ablative CO 2 lasers, in combination with topical betamethasone solution and NB-UVB, was suitable for stable non-segmental vitiligo. For vitiligo, the ablative fractional CO 2 laser is more effective than the non-ablative fractional laser.

Fractional CO2 laser is as effective as Q-switched ruby laser for the initial treatment of a traumatic tattoo.

Science.gov (United States)

Seitz, Anna-Theresa; Grunewald, Sonja; Wagner, Justinus A; Simon, Jan C; Paasch, Uwe

2014-12-01

Q-switched laser treatments are considered the standard method for removing both regular and traumatic tattoos. Recently, the removal of tattoo ink using ablative fractional lasers has been reported. Ablative fractional CO2 laser and q-switched ruby laser treatments were used in a split-face mode to compare the safety and efficacy of the two types of laser in removing a traumatic tattoo caused by the explosion of a firework. A male patient suffering from a traumatic tattoo due to explosive deposits in his entire face was subjected to therapy. A series of eleven treatments were performed. The right side of the face was always treated using an ablative fractional CO2 laser, whereas the left side was treated only using a q-switched ruby laser. After a series of eleven treatments, the patient demonstrated a significant lightening on both sides of his traumatic tattoo, with no clinical difference. After the first six treatments, the patient displayed greater lightening on the right side of his face, whereas after another five treatments, the left side of the patient's face appeared lighter. No side effects were reported. In the initial stage of removing the traumatic tattoo, the ablative fractional laser treatment appeared to be as effective as the standard ruby laser therapy. However, from the 6th treatment onward, the ruby laser therapy was more effective. Although ablative fractional CO2 lasers have the potential to remove traumatic tattoos, they remain a second-line treatment option.

Next generation Er:YAG fractional ablative laser

Science.gov (United States)

Heinrich, A.; Vizhanyo, A.; Krammer, P.; Summer, S.; Gross, S.; Bragagna, T.; Böhler, C.

2011-03-01

Pantec Biosolutions AG presents a portable fractional ablative laser system based on a miniaturized diode pumped Er:YAG laser. The system can operate at repetition rates up to 500 Hz and has an incorporated beam deflection unit. It is smaller, lighter and cost efficient compared to systems based on lamp pumped Er:YAG lasers and incorporates a skin layer detection to guarantee precise control of the microporation process. The pulse parameters enable a variety of applications in dermatology and in general medicine, as demonstrated by first results on transdermal drug delivery of FSH (follicle stimulating hormone).

Laser corrective surgery with fractional carbon dioxide laser following full-thickness skin grafts

Directory of Open Access Journals (Sweden)

Emily Forbat

2017-01-01

Full Text Available Full-thickness skin grafts (FTSGs are frequently used to treat patients with burn injuries and to repair defects rendered by excisional (including Mohs surgery. The evidence for corrective laser surgery after scar formation is well established. With regard to laser treatment of FTSG, the evidence is sparse. Laser treatment after FTSG is a novel concept, with minimal literature. We present a case series, one of the first to our knowledge, of the treatment of FTSG with fractional CO2 laser in five patients after Mohs surgery.

Histological evaluation of vertical laser channels from ablative fractional resurfacing

DEFF Research Database (Denmark)

Skovbølling Haak, Christina; Illes, Monica; Paasch, Uwe

2011-01-01

Ablative fractional resurfacing (AFR) represents a new treatment potential for various skin conditions and new laser devices are being introduced. It is important to gain information about the impact of laser settings on the dimensions of the created laser channels for obtaining a safe...... and efficient treatment outcome. The aim of this study was to establish a standard model to document the histological tissue damage profiles after AFR and to test a new laser device at diverse settings. Ex vivo abdominal pig skin was treated with a MedArt 620, prototype fractional carbon dioxide (CO(2)) laser...... (Medart, Hvidovre, Denmark) delivering single microbeams (MB) with a spot size of 165 µm. By using a constant pulse duration of 2 ms, intensities of 1-18 W, single and 2-4 stacked pulses, energies were delivered in a range from 2-144 mJ/MB. Histological evaluations included 3-4 high-quality histological...

Histological evaluation of vertical laser channels from ablative fractional resurfacing

DEFF Research Database (Denmark)

Skovbølling Haak, Christina; Illes, Monica; Paasch, Uwe

2011-01-01

Ablative fractional resurfacing (AFR) represents a new treatment potential for various skin conditions and new laser devices are being introduced. It is important to gain information about the impact of laser settings on the dimensions of the created laser channels for obtaining a safe...... and efficient treatment outcome. The aim of this study was to establish a standard model to document the histological tissue damage profiles after AFR and to test a new laser device at diverse settings. Ex vivo abdominal pig skin was treated with a MedArt 620, prototype fractional carbon dioxide (CO(2)) laser...... (Medart, Hvidovre, Denmark) delivering single microbeams (MB) with a spot size of 165 μm. By using a constant pulse duration of 2 ms, intensities of 1-18 W, single and 2-4 stacked pulses, energies were delivered in a range from 2-144 mJ/MB. Histological evaluations included 3-4 high-quality histological...

The picosecond laser for tattoo removal.

Science.gov (United States)

Hsu, Vincent M; Aldahan, Adam S; Mlacker, Stephanie; Shah, Vidhi V; Nouri, Keyvan

2016-11-01

The prevalence of tattoos continues to grow as modern society's stigma towards this form of body art shifts towards greater acceptance. Approximately one third of Americans aged 18-25 and 40 % of Americans aged 26-40 are tattooed. As tattoos continue to rise in popularity, so has the demand for an effective method of tattoo removal such as lasers. The various colors of tattoo inks render them ideal targets for specific lasers using the principle of selective photothermolysis. Traditional laser modalities employed for tattoo removal operate on pulse durations in the nanosecond domain. However, this pulse duration range is still too long to effectively break ink into small enough particles. Picosecond (10 -12 ) lasers have emerged at the forefront of laser tattoo removal due to their shorter pulse lengths, leading to quicker heating of the target chromophores, and consequently, more effective tattoo clearance. Recent studies have cited more effective treatment outcomes using picosecond lasers. Future comparative studies between picosecond lasers of various settings are necessary to determine optimal laser parameters for tattoo clearance.

Fractional CO(2) laser-assisted drug delivery

DEFF Research Database (Denmark)

Haedersdal, Merete; Sakamoto, Fernanda H; Farinelli, William A

2010-01-01

Ablative fractional resurfacing (AFR) creates vertical channels that might assist the delivery of topically applied drugs into skin. The purpose of this study was to evaluate drug delivery by CO(2) laser AFR using methyl 5-aminolevulinate (MAL), a porphyrin precursor, as a test drug....

Facelift combined with simultaneous fractional laser resurfacing: Outcomes and complications.

Science.gov (United States)

Wright, Eric J; Struck, Steve K

2015-10-01

The combination of simultaneous surgical rhytidectomy with ablative resurfacing has been a controversial procedure due to the concern of postoperative wound healing. Traditional ablative resurfacing lasers are believed to have higher rates of complications, leading to delayed healing and skin flap loss when combined with face rhytidectomy surgeries. With the development of fractionated ablative laser therapy, there has been increased interest in combining these two procedures. The objective of this study is to evaluate the clinical outcomes of patients undergoing simultaneous full-face rhytidectomy in combination with fractionated ablative skin resurfacing. A retrospective chart analysis was performed for all patients who had a combined procedure of facelift and ablative fractional laser resurfacing from 2008 to 2013 by the senior author (SKS). Postoperative recovery and complications were recorded. The surgical technique used for performing the facelift was an extended supraplatysmal dissection with SMAS plication. Fraxel Re:Pair 10,600-nm fractional carbon dioxide laser was used to perform an ablative resurfacing including the elevated skin flaps. A total of 86 patients were included. Average age was 60.01 years (range of 45-78 years). Longest follow up was five years. The average size of the elevated skin flaps was 100 cm(2). Average skin type was a Fitzpatrick type 2. All patients had complete re-epithelialization by one week after their procedure. Four patients (4.6%) experienced acne outbreaks. Four patients (4.6%) had facial erythema that persisted greater than two weeks. Of these four patients, all resolved by five weeks postoperatively. There was no delayed wound healing or skin flap loss observed. Our results indicate that simultaneous rhytidectomy with fractionated ablative laser resurfacing does not cause an increase in wound healing or skin loss. Due to improved patient outcomes with combining these procedures, we believe that this can be increasingly

Laser-induced incandescence: Towards quantitative soot volume fraction measurements

Energy Technology Data Exchange (ETDEWEB)

Tzannis, A P; Wienbeucker, F; Beaud, P; Frey, H -M; Gerber, T; Mischler, B; Radi, P P [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1999-08-01

Laser-Induced Incandescence has recently emerged as a versatile tool for measuring soot volume fraction in a wide range of combustion systems. In this work we investigate the essential features of the method. LII is based on the acquisition of the incandescence of soot when heated through a high power laser pulse. Initial experiments have been performed on a model laboratory flame. The behaviour of the LII signal is studied experimentally. By applying numerical calculations we investigate the possibility to obtain two-dimensional soot volume fraction distributions. For this purpose a combination of LII with other techniques is required. This part is discussed in some extent and the future work is outlined. (author) 4 figs., 3 refs.

Fractional versus ablative erbium:yttrium-aluminum-garnet laser resurfacing for facial rejuvenation: an objective evaluation.

Science.gov (United States)

El-Domyati, Moetaz; Abd-El-Raheem, Talal; Abdel-Wahab, Hossam; Medhat, Walid; Hosam, Wael; El-Fakahany, Hasan; Al Anwer, Mustafa

2013-01-01

Laser is one of the main tools for skin resurfacing. Erbium:yttrium-aluminum-garnet (Er:YAG) was the second ablative laser, after carbon dioxide, emitting wavelength of 2940 nm. Fractional laser resurfacing has been developed to overcome the drawbacks of ablative lasers. We aimed to objectively evaluate the histopathological and immunohistochemical effects of Er:YAG 2940-nm laser for facial rejuvenation (multiple sessions of fractional vs single session of ablative Er:YAG laser). Facial resurfacing with single-session ablative Er:YAG laser was performed on 6 volunteers. Another 6 were resurfaced using fractional Er:YAG laser (4 sessions). Histopathological (hematoxylin-eosin, orcein, Masson trichrome, and picrosirius red stains) and immunohistochemical assessment for skin biopsy specimens were done before laser resurfacing and after 1 and 6 months. Histometry for epidermal thickness and quantitative assessment for neocollagen formation; collagen I, III, and VII; elastin; and tropoelastin were done for all skin biopsy specimens. Both lasers resulted in increased epidermal thickness. Dermal collagen showed increased neocollagen formation with increased concentration of collagen types I, III, and VII. Dermal elastic tissue studies revealed decreased elastin whereas tropoelastin concentration increased after laser resurfacing. Neither laser showed significant difference between their effects clinically and on dermal collagen. Changes in epidermal thickness, elastin, and tropoelastin were significantly more marked after ablative laser. The small number of patients is a limitation, yet the results show significant improvement. Multiple sessions of fractional laser have comparable effects to a single session of ablative Er:YAG laser on dermal collagen but ablative laser has more effect on elastic tissue and epidermis. Copyright © 2012 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

The impact of treatment density and molecular weight for fractional laser-assisted drug delivery

DEFF Research Database (Denmark)

Haak, Christina S; Bhayana, Brijesh; Farinelli, William A

2012-01-01

Ablative fractional lasers (AFXL) facilitate uptake of topically applied drugs by creating narrow open micro-channels into the skin, but there is limited information on optimal laser settings for delivery of specific molecules. The objective of this study was to investigate the impact of laser...... treatment density (% of skin occupied by channels) and molecular weight (MW) for fractional CO(2) laser-assisted drug delivery. AFXL substantially increased intra- and transcutaneous delivery of polyethylene glycols (PEGs) in a MW range from 240 to 4300 Da (Nuclear Magnetic Resonance, p...

Hypertrophic Scarring of the Neck Following Ablative Fractional Carbon Dioxide Laser Resurfacing

Science.gov (United States)

Avram, Mathew M.; Tope, Whitney D.; Yu, Thomas; Szachowicz, Edward; Nelson, J. Stuart

2009-01-01

Background Ablative fractional carbon dioxide (CO2) laser treatments have gained popularity due to their efficacy, shortened downtime, and decreased potential for scarring in comparison to traditional ablative CO2 resurfacing. To date, scarring with fractional CO2 lasers has not been reported. Objective Five patients treated with the same fractional CO2 laser technology for photodamage of the neck were referred to our practices 1–3 months after treatment. Each patient developed scarring. Of the five cases, two are discussed in detail. The first was treated under general anesthesia on the face and anterior neck at a pulse energy of 30 mJ (859 μm depth) with 25% coverage. Eleven days after treatment, three non-healing areas along the horizontal skin folds of the anterior neck were noted. At 2 weeks after CO2 ablative fractional resurfacing, these areas had become thickened. These raised areas were treated with a non-ablative fractionated 1,550 nm laser to modify the wound healing milieu. One week later, distinct firm pale papules in linear arrays with mild hypopigmentation had developed along involved neck skin folds. Skin biopsy was performed. For the second patient, the neck was treated at a pulse energy of 20 mJ (630 μm depth) with 30% coverage of the exposed skin, with a total treatment energy of 5.0 kJ. Minimal crusting was noted on the neck throughout the initial healing phase of 2 weeks. She then experienced tightness on her neck. Approximately 3 weeks after treatment, she developed multiple vertical and horizontal hypertrophic scars (HS). Results Histopathology for the first case confirmed the presence of a hypertrophic scar. The papules in this case completely resolved with mild residual hypopigmentation after treatment with topical corticosteroids. HS failed to resolve in the second case to date after 1 month. Conclusion As with traditional ablative CO2 laser resurfacing, HS is a potential complication of ablative fractional CO2 laser resurfacing

The role of transforming growth factor β1 in fractional laser resurfacing with a carbon dioxide laser.

Science.gov (United States)

Jiang, Xia; Ge, Hongmei; Zhou, Chuanqing; Chai, Xinyu; Deng, Hui

2014-03-01

The aim of this study was to investigate the role of transforming growth factor β1 in mechanisms of cutaneous remodeling induced by fractional carbon dioxide laser treatment. The dorsal skin of Kunming mice was exposed to a single-pass fractional CO2 laser treatment. Biopsies were taken at 1 h and at 1, 3, 7, 14, 21, 28, and 56 days after treatment. Transforming growth factor (TGF) β1 expression in skin samples was evaluated by ELISA, dermal thickness by hematoxylin-eosin staining, collagen and elastic fibers by Ponceau S and Victoria blue double staining, and types I and III collagens by ELISA. The level of TGF β1 in the laser-treated areas of skin was significantly increased compared with that in the control areas on days 1 (p skin of the laser-treated areas had increased significantly (p resurfacing.

Direct quantitative comparison of molecular responses in photodamaged human skin to fractionated and fully ablative carbon dioxide laser resurfacing.

Science.gov (United States)

Orringer, Jeffrey S; Sachs, Dana L; Shao, Yuan; Hammerberg, Craig; Cui, Yilei; Voorhees, John J; Fisher, Gary J

2012-10-01

Fractionated ablative laser resurfacing has become a widely used treatment modality. Its clinical results are often found to approach those of traditional fully ablative laser resurfacing. To directly compare the molecular changes that result from fractionated and fully ablative carbon dioxide (CO(2)) laser resurfacing in photodamaged human skin. Photodamaged skin of 34 adult volunteers was focally treated at distinct sites with a fully ablative CO(2) laser and a fractionated CO(2) laser. Serial skin samples were obtained at baseline and several time points after treatment. Real-time reverse transcriptase polymerase chain reaction technology and immunohistochemistry were used to quantify molecular responses to each type of laser treatment. Fully ablative and fractionated CO(2) laser resurfacing induced significant dermal remodeling and collagen induction. After a single treatment, fractionated ablative laser resurfacing resulted in collagen induction that was approximately 40% to 50% as pronounced as that induced by fully ablative laser resurfacing. The fundamental cutaneous responses that result from fully ablative and fractionated carbon dioxide laser resurfacing are similar but differ in magnitude and duration, with the fully ablative procedure inducing relatively greater changes including more pronounced collagen induction. However, the molecular data reported here provide substantial support for fractionated ablative resurfacing as an effective treatment modality for improving skin texture. © 2012 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

Elemental fractionation in 785 nm picosecond and femtosecond laser ablation inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Shaheen, M.E.; Gagnon, J.E.; Fryer, B.J.

2015-01-01

Elemental fractionation and ICP-MS signal response were investigated for two different pulse width laser beams originating from the same laser system. Femtosecond and picosecond laser beams at pulse widths of 130 fs and 110 ps, respectively, and wavelength of 785 nm were used to ablate NIST 610 synthetic glass and SRM 1107 Naval Brass B at the same spot for 800 to 1000 laser pulses at different repetition rates (5 to 50 Hz). Elemental fractionation was found to depend on repetition rate and showed a trend with femtosecond laser ablation that is opposite to that observed in picosecond laser ablation for most measured isotopes. ICP-MS signal intensity was higher in femtosecond than picosecond LA-ICP-MS in both NIST 610 and naval brass when ablation was conducted under the same fluence and repetition rate. The differences in signal intensity were partly related to differences in particle size distribution between particles generated by femtosecond and picosecond laser pulses and the consequent differences in transport and ionization efficiencies. The main reason for the higher signal intensity resulting from femtosecond laser pulses was related to the larger crater sizes compared to those created during picosecond laser ablation. Elemental ratios measured using 66 Zn/ 63 Cu, 208 Pb/ 238 U, 232 Th/ 238 U, 66 Zn/ 232 Th and 66 Zn/ 208 Pb were found to change with the number of laser pulses with data points being more scattered in picosecond than femtosecond laser pulses. Reproducibility of replicate measurements of signal intensities, fractionation and elemental ratios was better for fs-LA-ICP-MS (RSD ~ 3 to 6%) than ps-LA-ICP-MS (RSD ~ 7 to 11%). - Highlights: • Fractionation and ICP-MS signal response were investigated for two different pulse widths using NIST 610 and Naval Brass. • Dependence of fractionation indices on repetition rate and pulse width. • Higher ablation rate was observed in picosecond compared to femtosecond laser ablation of NIST 610 and Brass

Management of vascular lesions using advanced laser technology

Directory of Open Access Journals (Sweden)

Christofer Tzermias

2017-04-01

Full Text Available One of the most widely used cutaneous applications of Light Amplification by Stimulated Emission of Radiation (laser concerns the treatment of vascular lesions. During the past two decades, very significant advances in the application of laser technology in dermatology have occurred, with selective photothermolysis being the most important. This review focuses on the application of modern laser devices (Pulsed Dye Laser, or PDL; potassium titanyl phosphate laser, or KTP; diode laser; and neodymium-doped yttrium-aluminium-garnet laser, or Nd:YAG, as well as the combination of laser and photodynamic therapy (PDT for the treatment of vascular lesions. In particular, both congenital (haemangiomas and port-wine stains and acquired vascular lesions (facial and leg telangiectasias, rosacea, Poikiloderma of Civatte, spider angioma, pyogenic granuloma, and venous lakes are discussed. The review of many recent research studies demonstrates that modern applications of lasers in dermatology constitute the finest method for the treatment of vascular lesions, combining the advantages of invasive therapy with the security offered by non-invasive therapy, while in certain cases they are the single and only choice for the treatment of these lesions.

Subrecoil laser cooling dynamics: a fractional derivative approach

International Nuclear Information System (INIS)

Uchaikin, Vladimir V; Sibatov, Renat T

2009-01-01

The subrecoil laser cooling process is considered in the framework of a model with two states (trapping and recycling), with instantaneous transitions between them. The key point of the work is the use of a fractional exponential function for waiting time distributions. This allows us to derive a general master equation covering both important cases: those with exponential and power type tails. Their solutions are expressed through fractionally stable distributions. The pdfs of the total trapping time of an atom and the proportion of trapped atoms are found. Analytical relationships show a good agreement with numerical results from Monte Carlo simulation

Molecular effects of fractional carbon dioxide laser resurfacing on photodamaged human skin.

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Reilly, Michael J; Cohen, Marc; Hokugo, Akishige; Keller, Gregory S

2010-01-01

Objective To elucidate the sequential changes in protein expression that play a role in the clinically beneficial results seen with fractional carbon dioxide (CO(2)) laser resurfacing of the face and neck. Methods Nine healthy volunteers were recruited for participation from the senior author's facial plastic surgery practice. After informed consent was obtained, each volunteer underwent a 2-mm punch biopsy from a discrete area of infra-auricular neck skin prior to laser treatment. Patients then immediately underwent laser resurfacing of photodamaged face and neck skin at a minimal dose (30 W for 0.1 second) with the Pixel Perfect fractional CO(2) laser. On completion of the treatment, another biopsy specimen was taken adjacent to the first site. Additional biopsy specimens were subsequently taken from adjacent skin at 2 of 3 time points (day 7, day 14, or day 21). RNA was extracted from the specimens, and reverse transcriptase-polymerase chain reaction and protein microarray analysis were performed. Comparisons were then made between time points using pairwise comparison testing. Results We found statistically significant changes in the gene expression of several matrix metalloproteinases (MMPs). The data demonstrate a consistent up-regulation of MMPs 1, 3, 9, and 13, all of which have been previously reported for fully ablative CO(2) laser resurfacing. There was also a statistically significant increase in MMP-10 and MMP-11 levels in this data set. Conclusion This study suggests that the molecular mechanisms of action are similar for both fractional and fully ablative CO(2) laser resurfacing.

Fractional Carbon Dioxide Laser for Keratosis Pilaris: A Single-Blind, Randomized, Comparative Study

Directory of Open Access Journals (Sweden)

Vasanop Vachiramon

2016-01-01

Full Text Available Objective. Keratosis pilaris (KP is a common condition which can frequently be cosmetically disturbing. Topical treatments can be used with limited efficacy. The objective of this study is to evaluate the effectiveness and safety of fractional carbon dioxide (CO2 laser for the treatment of KP. Patients and Methods. A prospective, randomized, single-blinded, intraindividual comparative study was conducted on adult patients with KP. A single session of fractional CO2 laser was performed to one side of arm whereas the contralateral side served as control. Patients were scheduled for follow-up at 4 and 12 weeks after treatment. Clinical improvement was graded subjectively by blinded dermatologists. Patients rated treatment satisfaction at the end of the study. Results. Twenty patients completed the study. All patients stated that the laser treatment improved KP lesions. At 12-week follow-up, 30% of lesions on the laser-treated side had moderate to good improvement according to physicians’ global assessment (p=0.02. Keratotic papules and hyperpigmentation appeared to respond better than the erythematous component. Four patients with Fitzpatrick skin type V developed transient pigmentary alteration. Conclusions. Fractional CO2 laser treatment may be offered to patients with KP. Dark-skinned patients should be treated with special caution.

Elemental fractionation in 785 nm picosecond and femtosecond laser ablation inductively coupled plasma mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Shaheen, M.E., E-mail: mshaheen73@science.tanta.edu.eg [Department of Physics, Faculty of Sciences, Tanta University, Tanta (Egypt); Gagnon, J.E.; Fryer, B.J. [Great Lakes Institute for Environmental Research (GLIER), University of Windsor, Windsor, Ontario N9B 3P4 (Canada); Department of Earth and Environmental Sciences, University of Windsor, Windsor, Ontario N9B 3P4 (Canada)

2015-05-01

Elemental fractionation and ICP-MS signal response were investigated for two different pulse width laser beams originating from the same laser system. Femtosecond and picosecond laser beams at pulse widths of 130 fs and 110 ps, respectively, and wavelength of 785 nm were used to ablate NIST 610 synthetic glass and SRM 1107 Naval Brass B at the same spot for 800 to 1000 laser pulses at different repetition rates (5 to 50 Hz). Elemental fractionation was found to depend on repetition rate and showed a trend with femtosecond laser ablation that is opposite to that observed in picosecond laser ablation for most measured isotopes. ICP-MS signal intensity was higher in femtosecond than picosecond LA-ICP-MS in both NIST 610 and naval brass when ablation was conducted under the same fluence and repetition rate. The differences in signal intensity were partly related to differences in particle size distribution between particles generated by femtosecond and picosecond laser pulses and the consequent differences in transport and ionization efficiencies. The main reason for the higher signal intensity resulting from femtosecond laser pulses was related to the larger crater sizes compared to those created during picosecond laser ablation. Elemental ratios measured using {sup 66}Zn/{sup 63}Cu, {sup 208}Pb/{sup 238}U, {sup 232}Th/{sup 238}U, {sup 66}Zn/{sup 232}Th and {sup 66}Zn/{sup 208}Pb were found to change with the number of laser pulses with data points being more scattered in picosecond than femtosecond laser pulses. Reproducibility of replicate measurements of signal intensities, fractionation and elemental ratios was better for fs-LA-ICP-MS (RSD ~ 3 to 6%) than ps-LA-ICP-MS (RSD ~ 7 to 11%). - Highlights: • Fractionation and ICP-MS signal response were investigated for two different pulse widths using NIST 610 and Naval Brass. • Dependence of fractionation indices on repetition rate and pulse width. • Higher ablation rate was observed in picosecond compared to

Fractional Carbon Dioxide Laser and its Combination with Subcision in Improving Atrophic Acne Scars.

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Nilforoushzadeh, Mohammad Ali; Faghihi, Gita; Jaffary, Fariba; Haftbaradaran, Elaheh; Hoseini, Sayed Mohsen; Mazaheri, Nafiseh

2017-01-01

Acne is a very common skin disease in which scars are seen in 95% of the patients. Although numerous treatments have been recommended, researchers are still searching for a single modality to treat the complication due to its variety in shape and depth. We compared the effects of fractional carbon dioxide (CO 2 ) laser alone and in combination with subcision in the treatment of atrophic acne scars. This clinical trial study was performed in Skin Diseases and Leishmaniasis Research Center (Isfahan, Iran) during 2011-2012. Eligible patients with atrophic acne scars were treated with fractional CO 2 laser alone (five sessions with 3-week interval) on the right side of the face and fractional CO 2 laser plus subcision (one session using both with four sessions of fractional CO 2 laser, with 3-week interval) on the left side. The subjects were visited 1, 2, and 6 months after the treatment. Patient satisfaction rate was analyzed using SPSS 20 software. The average of recovery rate was 54.7% using the combination method and 43.0% using laser alone ( P < 0.001). The mean patient satisfaction was significantly higher with the combination method than laser alone (6.6 ± 1.2 vs. 5.2 ± 1.8; P < 0.001). Bruising was only seen with the combination method and lasted for 1 week in 57.0% and for 2 weeks in 43.0%. Erythema was seen in both methods. Postinflammatory pigmentation and hyperpigmentation were associated with combination method. No persistent side effects were seen after 6 months. Using a combination of subcision and laser had suitable results regarding scar recovery and satisfaction rate.

Laser-assisted hair removal for facial hirsutism in women: A review of evidence.

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Lee, Chun-Man

2018-06-01

Poly cystic ovarian syndrome (PCOS) has been described as the common diagnosis for hirsutism in women. Facial hirsutism is by far the most distressing symptom of hyperandrogenism in women with PCOS. A statistically significant improvement in psychological well-being has been reported in patients with PCOS allocated for laser-assisted hair removal. The theory of selective photothermolysis has revolutionized laser hair removal in that it is effective and safe, when operated by sufficiently trained and experienced professionals. Long-pulsed ruby (694 nm), long-pulsed alexandrite (755 nm), diode (800-980 nm), and long-pulsed Nd:YAG (1064 nm) are commercially available laser devices for hair removal most widely studied. This article will introduce the fundamentals and mechanism of action of lasers in hair removal, in a contemporary literature review looking at medium to long term efficacy and safety profiles of various laser hair removal modalities most widely commercially available to date.

Hair regrowth through wound healing process after ablative fractional laser treatment in a murine model.

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Bae, Jung Min; Jung, Han Mi; Goo, Boncheol; Park, Young Min

2015-07-01

Alopecia is one of the most common dermatological problems in the elderly; however, current therapies for it are limited by low efficacy and undesirable side effects. Although clinical reports on fractional laser treatment for various alopecia types are increasing, the exact mechanism remains to be clarified. The purposes of this study were to demonstrate the effect of ablative fractional laser treatment on hair follicle regrowth in vivo and investigate the molecular mechanism after laser treatment. Ablative CO2 fractional laser was applied to the shaved dorsal skin of 7-week-old C57BL/6 mice whose hair was in the telogen stage. After 12 mice were treated at various energy (10-40 mJ/spot) and density (100-400 spots/cm(2) ) settings to determine the proper dosage for maximal effect. Six mice were then treated at the decided dosage and skin specimens were sequentially obtained by excision biopsy from the dorsal aspect of each mouse. Tissue samples were used for the immunohistochemistry and reverse transcription polymerase chain reaction assays to examine hair follicle status and their related molecules. The most effective dosage was the 10 mJ/spot and 300 spots/cm(2) setting. The anagen conversion of hair was observed in the histopathological examination, while Wnt/β-catenin expression was associated with hair regrowth in the immunohistochemistry and molecular studies. Ablative fractional lasers appear to be effective for inducing hair regrowth via activation of the Wnt/β-catenin pathway in vivo. Our findings indicate that fractional laser treatment can potentially be developed as new treatment options for stimulating hair regrowth. © 2015 Wiley Periodicals, Inc.

Micro-scale novel stable isotope fractionation during weathering disclosed by femtosecond laser ablation

Science.gov (United States)

Schuessler, J. A.; von Blanckenburg, F.

2012-12-01

The stable isotope fractionation of metals and metalloids during chemical weathering and alteration of rocks at low temperature is a topic receiving increasing scientific attention. For these systems, weathering of primary minerals leads to selective partitioning of isotopes between the secondary minerals formed from them, and the dissolved phase of soil or river water. While the isotopic signatures of these processes have been mapped-out at the catchment or the soil scale, the actual isotopic fractionation is occurring at the mineral scale. To identify the processes underlying such micro-scale fractionation, the development of micro-analytical tools allows to investigate mechanisms of isotope fractionation in-situ, in combination with textural information of weathering reactions. We have developed a second-generation UV femtosecond (fs) laser system at GFZ Potsdam. The advantage of UV-fs laser ablation is the reduction of laser-induced isotopic and elemental fractionation by avoiding 'thermal effects' during ablation, such that accurate isotope ratios can be measured by standard-sample-standard bracketing using laser ablation multicollector ICP-MS; where the matrix of the bracketing standard does not need to match that of the sample [1]. Our system consists of the latest generation femtosecond solid-state laser (Newport Spectra Physics Solstice), producing an ultra short pulse width of about 100 femtoseconds at a wavelength of 196 nm. The system is combined with a custom-build computer-controlled sample stage and allows fully automated isotope analyses through synchronised operation of the laser with the Neptune MC-ICP-MS. To assess precision and accuracy of our laser ablation method, we analysed various geological reference materials. We obtained δ30Si values of -0.31 ± 0.23 (2SD, n = 13) for basalt glass BHVO-2G, and -1.25 ± 0.21 (2SD, n = 27) for pure Si IRMM17 when bracketed against NBS-28 quartz. δ56Fe and δ26Mg values obtained from non-matrix matched

Determination of pulse energy dependence for skin denaturation from 585nm fibre laser

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Mujica-Ascencio, S.; Velazquez-Gonzalez, J. S.; Mujica-Ascencio, C.; Alvarez-Chavez, J. A.

2014-05-01

In this paper, simulation and mathematical analysis for the determination of pulse energy from a Q-switched Yb3+-doped fibre laser is required in Port Wine Stain (PWS) treatment. The pulse energy depends on average power, gain, volume, repetition rate and pulse duration. In some treatments such as Selective Photothermolysis (SP), the peak power at the end of the optical fibre and pulse duration can be obtained and modified via a cavity design. For that purpose, a 585nm optical fibre laser full design which considers all of the above besides the average losses through the optical devices proposed for the design and the Ytterbium optical fibre overall gain will be presented.

Use of 1540nm fractionated erbium:glass laser for split skin graft resurfacing: a case study.

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Narinesingh, S; Lewis, S; Nayak, B S

2013-09-01

The field of laser skin resurfacing has evolved rapidly over the past two decades from ablative lasers, to nonablative systems using near-infrared, intense-pulsed light and radio-frequency systems, and most recently fractional laser resurfacing. Although fractional thermolysis is still in its infancy, its efficacy in in the treatment of skin disorders have been clearly demonstrated. Here we present a case report on the safety and efficacy of a 1540nm erbium:glass laser in the treatment of the waffle pattern of a meshed skin graft in a 38-year-old patient with type V skin in the Caribbean.

Pattern analysis of laser-tattoo interactions for picosecond- and nanosecond-domain 1,064-nm neodymium-doped yttrium-aluminum-garnet lasers in tissue-mimicking phantom.

Science.gov (United States)

Ahn, Keun Jae; Zheng, Zhenlong; Kwon, Tae Rin; Kim, Beom Joon; Lee, Hye Sun; Cho, Sung Bin

2017-05-08

During laser treatment for tattoo removal, pigment chromophores absorb laser energy, resulting in fragmentation of the ink particles via selective photothermolysis. The present study aimed to outline macroscopic laser-tattoo interactions in tissue-mimicking (TM) phantoms treated with picosecond- and nanosecond-domain lasers. Additionally, high-speed cinematographs were captured to visualize time-dependent tattoo-tissue interactions, from laser irradiation to the formation of photothermal and photoacoustic injury zones (PIZs). In all experimental settings using the nanosecond or picosecond laser, tattoo pigments fragmented into coarse particles after a single laser pulse, and further disintegrated into smaller particles that dispersed toward the boundaries of PIZs after repetitive delivery of laser energy. Particles fractured by picosecond treatment were more evenly dispersed throughout PIZs than those fractured by nanosecond treatment. Additionally, picosecond-then-picosecond laser treatment (5-pass-picosecond treatment + 5-pass-picosecond treatment) induced greater disintegration of tattoo particles within PIZs than picosecond-then-nanosecond laser treatment (5-pass-picosecond treatment + 5-pass-nanosecond treatment). High-speed cinematography recorded the formation of PIZs after repeated reflection and propagation of acoustic waves over hundreds of microseconds to a few milliseconds. The present data may be of use in predicting three-dimensional laser-tattoo interactions and associated reactions in surrounding tissue.

Clinical effects of non-ablative and ablative fractional lasers on various hair disorders: a case series of 17 patients.

Science.gov (United States)

Cho, Suhyun; Choi, Min Ju; Zheng, Zhenlong; Goo, Boncheol; Kim, Do-Young; Cho, Sung Bin

2013-04-01

Both ablative and non-ablative fractional lasers have been applied to various uncommon hair disorders. The purpose of this study was to demonstrate the clinical effects of fractional laser therapy on the course of primary follicular and perifollicular pathologies and subsequent hair regrowth. A retrospective review of 17 patients with uncommon hair disorders - including ophiasis, autosomal recessive woolly hair/hypotrichosis, various secondary cicatricial alopecias, pubic hypotrichosis, frontal fibrosing alopecia, and perifolliculitis abscedens et suffodiens - was conducted. All patients had been treated with non-ablative and/or ablative fractional laser therapies. The mean clinical improvement score in these 17 patients was 2.2, while the mean patient satisfaction score was 2.5. Of the 17 subjects, 12 (70.6%) demonstrated a clinical response to non-ablative and/or ablative fractional laser treatments, including individuals with ophiasis, autosomal recessive woolly hair/hypotrichosis, secondary cicatricial alopecia (scleroderma and pressure-induced alopecia), frontal fibrosing alopecia, and perifolliculitis abscedens et suffodiens. Conversely, patients with long-standing ophiasis, surgical scar-induced secondary cicatricial alopecia, and pubic hypotrichosis did not respond to fractional laser therapy. Our findings demonstrate that the use of non-ablative and/or ablative fractional lasers promoted hair growth in certain cases of uncommon hair disorders without any remarkable side effects.

Polydeoxyribonucleotide improves wound healing of fractional laser resurfacing in rat model.

Science.gov (United States)

Yu, Mi; Lee, Jun Young

2017-02-01

Polydeoxyribonucleotide (PDRN) is an active compound that can promote wound healing. PDRN stimulates wound healing by enhancing angiogenesis and increasing fibroblast growth rates. Laser skin resurfacing is a popular cosmetic procedure for skin rejuvenation. Despite excellent improvement of photo-damaged skin and acne scarring, it is accompanied with drawbacks, such as prolonged erythema and crusting. This study was designed to assess the effect of PDRN on wounds induced by fractional laser resurfacing. Twelve male rats aged 8 weeks were randomly assigned to the PDRN treatment group and the control group. Wounds were induced using a fractional ablative CO 2 laser. The treatment group received daily injections of PDRN and the control group received injections of the vehicle. Wound healing assessed by clinical features and histopathologic findings. The process of wound healing was faster in the treatment group than in the control group. In the histopathological examination, the granulation tissue thickness score of the treatment group was significantly higher than that of the control group. Results of immunohistochemical staining showed a marked increase of VEGF-positive cells and PECAM-1/CD31-positive microvessels in the treatment group. PDRN may be a beneficial option to promote wound healing after laser treatment.

Fractional Nonablative 1540 nm Laser Resurfacing for Thermal Burn Scars: A Randomized Controlled Trial

DEFF Research Database (Denmark)

Haedersdal, M.; Moreau, K.E.R.; Beyer, D.M.

2009-01-01

Background and Objective: Burn scars cause permanent and disfiguring problems for many patients and limited treatments are available. Nonablative fractional lasers induce a wound healing response, which may lead to remodeling of burn sear texture. This randomized trial evaluates efficacy and adve......Background and Objective: Burn scars cause permanent and disfiguring problems for many patients and limited treatments are available. Nonablative fractional lasers induce a wound healing response, which may lead to remodeling of burn sear texture. This randomized trial evaluates efficacy...

Treatment of dilated pores with 1410-nm fractional erbium-doped fiber laser.

Science.gov (United States)

Suh, Dong-Hye; Chang, Ka-Yeun; Lee, Sang-Jun; Song, Kye-Yong; Choi, Jeong Hwee; Shin, Min Kyung; Jeong, Ki-Heon

2015-04-01

Dilated pores can be an early sign of skin aging and are a significant cosmetic concern. The 1410-nm wavelength is optimal for superficial dermal treatments up to 650 μm deep. The aim of the present study was to evaluate the clinical effectiveness and safety of the fractional erbium-doped fiber 1410-nm laser in the treatment of dilated pores. Fifteen patients with dilated facial pores underwent three laser treatments at 3-week intervals. Posttreatment skin responses and side effects were assessed at treatment and follow-up visits by study physicians. Clinical effectiveness of treatment was assessed by both study physicians and patients 3 months after the final laser treatment using a quartile grading scale. Histological examination was performed using biopsy samples taken at baseline (pretreatment) and 3 months after the last treatment. This study showed that greater than 51 % improvement in dilated pores was demonstrated in 14 of 15 patients after three sessions of laser treatments. Improvements in skin texture, tone, and smoothness were reported in all patients. Treatment was well tolerated in all patients, with no unanticipated side effects. This study demonstrates that the 1410-nm fractional erbium fiber laser is effective and safe for treatment of dilated facial pores in Fitzpatrick skin types III-IV.

Soot volume fraction fields in unsteady axis-symmetric flames by continuous laser extinction technique.

Science.gov (United States)

Kashif, Muhammad; Bonnety, Jérôme; Guibert, Philippe; Morin, Céline; Legros, Guillaume

2012-12-17

A Laser Extinction Method has been set up to provide two-dimensional soot volume fraction field time history at a tunable frequency up to 70 Hz inside an axis-symmetric diffusion flame experiencing slow unsteady phenomena preserving the symmetry. The use of a continuous wave laser as the light source enables this repetition rate, which is an incremental advance in the laser extinction technique. The technique is shown to allow a fine description of the soot volume fraction field in a flickering flame exhibiting a 12.6 Hz flickering phenomenon. Within this range of repetition rate, the technique and its subsequent post-processing require neither any method for time-domain reconstruction nor any correction for energy intrusion. Possibly complemented by such a reconstruction method, the technique should support further soot volume fraction database in oscillating flames that exhibit characteristic times relevant to the current efforts in the validation of soot processes modeling.

Intensified photodynamic therapy of actinic keratoses with fractional CO2 laser

DEFF Research Database (Denmark)

Togsverd-Bo, K; Haak, C S; Thaysen-Petersen, D

2012-01-01

Photodynamic therapy (PDT) with methyl aminolaevulinate (MAL) is effective for thin actinic keratoses (AKs) in field-cancerized skin. Ablative fractional laser resurfacing (AFXL) creates vertical channels that facilitate MAL uptake and may improve PDT efficacy....

Histologic analyses on the response of the skin to 1,927-nm fractional thulium fiber laser treatment.

Science.gov (United States)

Kwon, In Ho; Bae, Youin; Yeo, Un-Cheol; Lee, Jin Yong; Kwon, Hyuck Hoon; Choi, Young Hee; Park, Gyeong-Hun

2018-02-01

The histologic responses to varied parameters of 1,927-nm fractional thulium fiber laser treatment have not yet been sufficiently elucidated. This study sought to evaluate histologic changes immediately after 1,927-nm fractional thulium fiber laser session at various parameters. The dorsal skin of Yucatan mini-pig was treated with 1,927-nm fractional thulium fiber laser at varied parameters, with or without skin drying. The immediate histologic changes were evaluated to determine the effects of varying laser parameters on the width and the depth of treated zones. The increase in the level of pulse energy widened the area of epidermal changes in the low power level, but increased the dermal penetration depth in the high power level. As the pulse energy level increased, the increase in the power level under the given pulse energy level more evidently made dermal penetration deeper and the treatment area smaller. Skin drying did not show significant effects on epidermal changes, but evidently increased the depth of dermal denaturation under both high and low levels of pulse energy. These results may provide important information to establish treatment parameters of the 1,927-nm fractional thulium fiber laser for various skin conditions.

Pseudoxanthoma Elasticum Treatment with Fractional CO2 Laser

Directory of Open Access Journals (Sweden)

Alessandra Grassi Salles, MD, PhD

2014-09-01

Full Text Available Summary: Pseudoxanthoma elasticum (PE is a rare genetic disease characterized by calcification and fragmentation of elastic fibers of the skin, retina, and cardiovascular system. We report a case of PE in which fractional carbon dioxide laser treatment was successfully used to achieve improvement of the cervical skin with 2-year follow-up, in a patient with Fitzpatrick skin type IV. After the fifth session, the patient presented with a local herpes infection. The postlaser reaction of the PE skin was similar to that of the normal skin, in terms of the duration of redness, pain, swelling, and duration of crusting. The overall cosmetic result was satisfactory, with improvement in skin texture, irregularity, volume, and distensibility. The herpetic infection reinforces the value of antiviral prophylaxis during laser treatment of extrafacial areas.

Micro-fractional ablative skin resurfacing with two novel erbium laser systems.

Science.gov (United States)

Dierickx, Christine C; Khatri, Khalil A; Tannous, Zeina S; Childs, James J; Cohen, Richard H; Erofeev, Andrei; Tabatadze, David; Yaroslavsky, Ilya V; Altshuler, Gregory B

2008-02-01

Fractional ablation offers the potential benefits of full-surface ablative skin resurfacing while minimizing adverse effects. The purpose of this study was to evaluate the safety, damage profile, and efficacy of erbium fractional lasers. Histology from animal and human skin as well as clinical evaluations were conducted with erbium YAG (2,940 nm) and erbium YSGG (2,790 nm) fractional lasers varying pulse width, microbeam (microb) energy, number of passes, and stacking of pulses. Single-pulse treatment parameters from 1 to 12 mJ per 50-70 microm diameter microbeam and 0.25-5 milliseconds pulse widths produced microcolumns of ablation with border coagulation of up to 100 microm width and 450 microm depth. Stacking of pulses generated deeper microcolumns. Clinical observations and in vivo histology demonstrate rapid re-epithelization and limited adverse side effects. Facial treatments were performed in the periorbital and perioral areas using 1-8 passes of single and stacked pulses. Treatments were well-tolerated and subjects could resume their normal routine in 4 days. A statistically significant reduction in wrinkle scores at 3 months was observed for both periorbital and perioral wrinkles using blinded grading. For periorbital treatments of four passes or more, over 90% had > or =1 score wrinkle reduction (0-9 scale) and 42% had > or =2. For perioral wrinkles, over 50% had substantial improvements (> or =2). The clinical observations and histology findings demonstrate that micro-fractional ablative treatment with 2,790 and 2,940 nm erbium lasers resulted in safe and effective wrinkle reduction with minimal patient downtime. The depth and width of the ablated microcolumns and varying extent of surrounding coagulation can be controlled and used to design new treatment procedures targeted for specific indications and areas such as moderate to severe rhytides and photodamaged skin.

Financial analysis of technology acquisition using fractionated lasers as a model.

Science.gov (United States)

Jutkowitz, Eric; Carniol, Paul J; Carniol, Alan R

2010-08-01

Ablative fractional lasers are among the most advanced and costly devices on the market. Yet, there is a dearth of published literature on the cost and potential return on investment (ROI) of such devices. The objective of this study was to provide a methodological framework for physicians to evaluate ROI. To facilitate this analysis, we conducted a case study on the potential ROI of eight ablative fractional lasers. In the base case analysis, a 5-year lease and a 3-year lease were assumed as the purchase option with a $0 down payment and 3-month payment deferral. In addition to lease payments, service contracts, labor cost, and disposables were included in the total cost estimate. Revenue was estimated as price per procedure multiplied by total number of procedures in a year. Sensitivity analyses were performed to account for variability in model assumptions. Based on the assumptions of the model, all lasers had higher ROI under the 5-year lease agreement compared with that for the 3-year lease agreement. When comparing results between lasers, those with lower operating and purchase cost delivered a higher ROI. Sensitivity analysis indicates the model is most sensitive to purchase method. If physicians opt to purchase the device rather than lease, they can significantly enhance ROI. ROI analysis is an important tool for physicians who are considering making an expensive device acquisition. However, physicians should not rely solely on ROI and must also consider the clinical benefits of a laser. (c) Thieme Medical Publishers.

Quantitative mixture fraction measurements in combustion system via laser induced breakdown spectroscopy

KAUST Repository

Mansour, Mohy S.

2015-01-01

Laser induced breakdown spectroscopy (LIBS) technique has been applied to quantitative mixture fraction measurements in flames. The measured spectra of different mixtures of natural gas and air are used to obtain the calibration parameters for local elemental mass fraction measurements and hence calculate the mixture fraction. The results are compared with the mixture fraction calculations based on the ratios of the spectral lines of H/N elements, H/O elements and C/(N+O) and they show good agreement within the reaction zone of the flames. Some deviations are observed outside the reaction zone. The ability of LIBS technique as a tool for quantitative mixture fraction as well as elemental fraction measurements in reacting and non-reacting of turbulent flames is feasible. © 2014 Elsevier Ltd. All rights reserved.

Efficiency of Carbon Dioxide Fractional Laser in Skin Resurfacing

Directory of Open Access Journals (Sweden)

Andrej Petrov

2016-05-01

CONCLUSION: Multifunctional fractional carbon dioxide laser used in treatment of patients with acne and pigmentation from acne, as well as in the treatment of scars from different backgrounds, is an effective and safe method that causes statistically significant better effect of the treatment, greater patients’ satisfaction, minimal side effects and statistically better response to the therapy, according to assessments by the patient and the therapist.

Synergistic skin heat shock protein expression in response to combined laser treatment with a diode laser and ablative fractional lasers.

Science.gov (United States)

Paasch, Uwe; Sonja, Grunewald; Haedersdal, Merete

2014-06-01

Diode laser-based skin heating has been shown to minimise scars by interfering with wound healing responses through the induction of heat shock proteins (HSP). HSP are also induced after ablative fractional laser (AFXL) wound healing. AFXL itself is highly recommended for scar treatment. Therefore, the sequential combination of both modalities may produce superior outcomes. The aim of this study was to examine the pretreatment effects of a diode laser before AFXL on wound healing responses in terms of HSP up-regulation in an in vitro model. Immediate responses and responses on days 1, 3 or 6 post-procedure were studied in an in vitro porcine skin model (n = 240). Untreated samples served as control. Immunohistochemical investigation (Hsp70) was performed in all untreated controls, diode laser-, AFXL-, and in diode laser + AFXL-treated samples. Hsp70 was shown to be up-regulated by all interventions between days 1 and 6 after interventions. The largest effect was caused by the combination of a diode laser and an AFXL procedure. Diode laser exposure induces a skin HSP response that can be further enhanced by sequential AFXL treatment. Clinical studies are necessary to investigate the dose response of HSP on scar formation and refine suitable laser exposure settings.

Fractional nonablative 1,540-nm laser resurfacing of atrophic acne scars. A randomized controlled trial with blinded response evaluation

DEFF Research Database (Denmark)

Hedelund, Lene; Moreau, Karen Estell R; Beyer, Ditte M

2010-01-01

as moderately or significantly improved. No differences were found in skin redness or pigmentation between before and after treatment. Patients experienced moderate pain, erythema, oedema, bullae, and crusts. No adverse effects were seen in untreated control areas. The nonablative 1,540-nm fractional laser......The efficacy of nonablative fractional laser resurfacing of acne scars has been described in case reports and uncontrolled trials. The present study is the first randomized controlled trial in this field. The aim of this study was to examine the efficacy and adverse effects of 1,540-nm nonablative...... fractional laser treatment of acne scars. Ten patients with acne scars were included. Two intraindividual areas of similar size and appearance within contralateral anatomical regions were randomized to (1) 3-monthly laser treatments with a StarLux 1,540-nm fractional handpiece, and (2) no treatment. Blinded...

Ablative fractional laser alters biodistribution of ingenol mebutate in the skin

DEFF Research Database (Denmark)

Erlendsson, A M; Taudorf, E H; Eriksson, A. H.

2015-01-01

Topically applied ingenol mebutate (IngMeb) is approved for field-treatment of actinic keratosis and is currently being investigated for treatment of non-melanoma skin cancer (NMSC). Ablative fractional lasers (AFXLs) generate microscopic ablation zones (MAZs) in the skin, which may help induce...

The clinical experience and efficacy of bipolar radiofrequency with fractional photothermolysis for aged Asian skin.

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Akita, Hirotaka; Sasaki, Ryosuke; Yokoyama, Yusuke; Negishi, Kei; Matsunaga, Kayoko

2014-10-01

Bipolar radiofrequency (RF) technology is developed based on fractional thermolysis, and the literature concerning the efficacy of the rejuvenation and treatment of acne scars has been reported in Europe and the United States of America. Therefore, we examined bipolar RF treatment using fractional thermolysis to evaluate the efficacy and safety of the treatment of Asian photo-aging skin, particularly 'wrinkles' and 'sagging.' Ten Japanese women (mean age: 58.6, skin type III-IV) received three fractional bipolar RF treatments every 4-6 weeks. For the objective evaluation, we evaluated the improvement of the wrinkles on the forehead, lateral canthus (crow's feet) and lower eyelid, and the sagging of the nasolabial fold using digital photographs captured using Visia(™) . For the subjective evaluation, the participants were asked to describe the improvements observed in the wrinkles on the forehead, lateral canthus (crow's feet) and lower eyelid, and sagging nasolabial fold and to evaluate the level pain experienced using a 10-point VAS score. The objective evaluation in each category showed significant improvements in the wrinkles on the lateral canthus (crow's feet) and lower eyelid. As for the nasolabial fold, 60% of the subjects showed improvements, scoring from good to excellent (51-100% improvement), although there was a little improvement of the wrinkle on the forehead. Similar improvements were observed in the subjective evaluation. During each treatment, oedema and erythema were observed in all participants, but the oedema disappeared the following day in all cases. However, mild erythema persisted for an average of 3.1 days. Micro debris disappeared after an average of 5.2 days. The participants were satisfied, as we allowed them to apply make-up the next day. There were no other severe adverse reactions observed during the treatment. The 10-point VAS score was 3.8, and no participants dropped out due to discomfort. Little improvement was observed in

The efficacy of autologous platelet-rich plasma combined with erbium fractional laser therapy for facial acne scars or acne.

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Zhu, Jiang-Ting; Xuan, Min; Zhang, Ya-Ni; Liu, Hong-Wei; Cai, Jin-Hui; Wu, Yan-Hong; Xiang, Xiao-Fei; Shan, Gui-Qiu; Cheng, Biao

2013-07-01

The aim of this study was to evaluate the efficacy of autologous platelet-rich plasma (PRP) combined with erbium fractional laser therapy for facial acne or acne scars. PRP combined with erbium fractional laser therapy was used for the treatment of 22 patients, including 16 patients who suffered from facial acne scars and 6 patients who suffered from acne scars concomitant with acne. Whole blood (40 ml) was collected from each patient, and following differential centrifugation, PRP was harvested. After using an erbium fractional laser, we applied PRP to the entire face of every patient. Digital photos were taken before and after the treatment for evaluation by dermatologists and the patients rated the efficacy on a 5-point scale. The erythema was moderate or mild, while its total duration was 50%, and 91% of the patients were satisfied; no acne inflammation was observed after treatment. PRP combined with erbium fractional laser therapy is an effective and safe approach for treating acne scars or acne, with minimal side-effects, and it simultaneously enhanced the recovery of laser-damaged skin.

Fractional Er:YAG laser assisting topical betamethasone solution in combination with NB-UVB for resistant non-segmental vitiligo.

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Yan, Ru; Yuan, Jinping; Chen, Hongqiang; Li, Yuan-Hong; Wu, Yan; Gao, Xing-Hua; Chen, Hong-Duo

2017-09-01

Resistant non-segmental vitiligo is difficult to be treated. Ablative erbium-YAG (Er:YAG) laser has been used in the treatment of vitiligo, but the ablation of entire epidermis frustrated the compliance of patients. The purpose of this study is to investigate the effects of fractional Er:YAG laser followed by topical betamethasone and narrow band ultraviolet B (NB-UVB) therapy in the treatment of resistant non-segmental vitiligo. The vitiligo lesions of each enrolled patient were divided into four treatment parts, which were all irradiated with NB-UVB. Three parts were, respectively, treated with low, medium, or high energy of Er:YAG laser, followed by topical betamethasone solution application. A control part was spared with laser treatment and topical betamethasone. The treatment period lasted 6 months. The efficacy was assessed by two blinded dermatologists. Treatment protocol with high energy of 1800 mJ/P of fractional Er:YAG laser followed by topical betamethasone solution and in combination with NB-UVB made 60% patients achieve marked to excellent improvement in white patches. The protocol with medium energy of 1200 mJ/P of laser assisted approximate 36% patients achieve such improvement. The two protocols, respectively, showed better efficacies than NB-UVB only protocol. However, fractional Er:YAG laser at low energy of 600 mJ/P did not provide such contributions to the treatment of vitiligo. The fractional Er:YAG laser in combination with topical betamethasone solution and NB-UVB was suitable for resistant non-segmental vitiligo. The energy of laser was preferred to be set at relatively high level.

Quantitative mixture fraction measurements in combustion system via laser induced breakdown spectroscopy

KAUST Repository

Mansour, Mohy S.; Imam, Hisham; Elsayed, Khaled A.; Elbaz, Ayman M.; Abbass, Wafaa

2015-01-01

Laser induced breakdown spectroscopy (LIBS) technique has been applied to quantitative mixture fraction measurements in flames. The measured spectra of different mixtures of natural gas and air are used to obtain the calibration parameters for local

Efficacy of Punch Elevation Combined with Fractional Carbon Dioxide Laser Resurfacing in Facial Atrophic Acne Scarring: A Randomized Split-face Clinical Study

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Faghihi, Gita; Nouraei, Saeid; Asilian, Ali; Keyvan, Shima; Abtahi-Naeini, Bahareh; Rakhshanpour, Mehrdad; Nilforoushzadeh, Mohammad Ali; Hosseini, Sayed Mohsen

2015-01-01

Background: A number of treatments for reducing the appearance of acne scars are available, but general guidelines for optimizing acne scar treatment do not exist. The aim of this study was to compare the clinical effectiveness and side effects of fractional carbon dioxide (CO2) laser resurfacing combined with punch elevation with fractional CO2 laser resurfacing alone in the treatment of atrophic acne scars. Materials and Methods: Forty-two Iranian subjects (age range 18–55) with Fitzpatrick skin types III to IV and moderate to severe atrophic acne scars on both cheeks received randomized split-face treatments: One side received fractional CO2 laser treatment and the other received one session of punch elevation combined with two sessions of laser fractional CO2 laser treatment, separated by an interval of 1 month. Two dermatologists independently evaluated improvement in acne scars 4 and 16 weeks after the last treatment. Side effects were also recorded after each treatment. Results: The mean ± SD age of patients was 23.4 ± 2.6 years. Clinical improvement of facial acne scarring was assessed by two dermatologists blinded to treatment conditions. No significant difference in evaluation was observed 1 month after treatment (P = 0.56). Their evaluation found that fractional CO2 laser treatment combined with punch elevation had greater efficacy than that with fractional CO2 laser treatment alone, assessed 4 months after treatment (P = 0.02). Among all side effects, coagulated crust formation and pruritus at day 3 after fractional CO2 laser treatment was significant on both treatment sides (P < 0.05). Conclusion: Concurrent use of fractional laser skin resurfacing with punch elevation offers a safe and effective approach for the treatment of acne scarring. PMID:26538695

Efficacy of punch elevation combined with fractional carbon dioxide laser resurfacing in facial atrophic acne scarring: A randomized split-face clinical study

Directory of Open Access Journals (Sweden)

Gita Faghihi

2015-01-01

Full Text Available Background: A number of treatments for reducing the appearance of acne scars are available, but general guidelines for optimizing acne scar treatment do not exist. The aim of this study was to compare the clinical effectiveness and side effects of fractional carbon dioxide (CO 2 laser resurfacing combined with punch elevation with fractional CO 2 laser resurfacing alone in the treatment of atrophic acne scars. Materials and Methods: Forty-two Iranian subjects (age range 18-55 with Fitzpatrick skin types III to IV and moderate to severe atrophic acne scars on both cheeks received randomized split-face treatments: One side received fractional CO 2 laser treatment and the other received one session of punch elevation combined with two sessions of laser fractional CO 2 laser treatment, separated by an interval of 1 month. Two dermatologists independently evaluated improvement in acne scars 4 and 16 weeks after the last treatment. Side effects were also recorded after each treatment. Results: The mean ± SD age of patients was 23.4 ± 2.6 years. Clinical improvement of facial acne scarring was assessed by two dermatologists blinded to treatment conditions. No significant difference in evaluation was observed 1 month after treatment (P = 0.56. Their evaluation found that fractional CO 2 laser treatment combined with punch elevation had greater efficacy than that with fractional CO 2 laser treatment alone, assessed 4 months after treatment (P = 0.02. Among all side effects, coagulated crust formation and pruritus at day 3 after fractional CO 2 laser treatment was significant on both treatment sides (P < 0.05. Conclusion: Concurrent use of fractional laser skin resurfacing with punch elevation offers a safe and effective approach for the treatment of acne scarring.

Nonlinear processes in laser-produced dense plasma (observation of the fractional harmonics)

International Nuclear Information System (INIS)

Lyu, K.S.

1988-01-01

One of the main issues of laser plasma physics interactions is harmonic generation. The harmonic emission spectrum provides clues as to which non-linear processes take place in the plasma. Several effects contribute to a given line as judged from the complexity of the actual spectra. Unfolding of them has not been done satisfactorily yet. Harmonic lines with half integer or integer orders have been observed, but the physics are far from complete. In this dissertation research, we observed the usual second harmonic generation and a set of fractional harmonics which we believe have been observed for the first time in plasma physics. The plasma was produced by a high power laser and we have characterized its properties from the analysis of the radiation spectra, including the harmonic lines, as measured using the methods of transient spectroscopy. We produced the plasma with a Nd:glass laser which had a 65 nsec pulse width (FWHM) with a total energy of up to 6 Joules. The targets were steel alloys, copper, and aluminum. The harmonic generation from the plasma with a planar metal target was not strong. But, it became stronger when we made a dead hole (cavity) at the laser spot on the target surface. The second harmonic line appears first before the time of the peak of laser pulse. The fractional harmonics, which are related to the laser wavelength by rational number other than integers or half integers, appear near or after the time of the laser peak and weaker in UV wavelength range but stronger if some atomic emission line are near by. To understand the plasma evolution better, we developed computer simulation codes. The codes contain all relevant processes necessary to compute the plasma evolution

Deep pulse fractional CO2 laser combined with a radiofrequency system: results of a case series.

Science.gov (United States)

Cannarozzo, Giovanni; Sannino, Mario; Tamburi, Federica; Chiricozzi, Andrea; Saraceno, Rosita; Morini, Cristiano; Nisticò, Steven

2014-07-01

The purpose of this study was evaluation of the safety and efficacy of this new combined technology that adds deep ablation to thermal stimulation. Minimally ablative or subablative lasers, such as fractional CO2 lasers, have been developed in an attempt to achieve the same clinical results observed with traditional ablative lasers, but with fewer side effects. Despite being an ablative laser, the system used in this study is able to produce a fractional supply of the beam of light. Fractional ablation of skin is performed through the development of microscopic vertical columns surrounded by spared areas of epidermis and dermis, ensuring rapid wound healing and minimum down time. Simultaneous synchronized delivery of a radiofrequency (RF) current to the deeper layers of the skin completes the therapeutic scenario, ensuring an effective skin tightening effect over the entire treated area. Nine adult patients were treated for wrinkles and acne scars using this new laser technology. An independent observer evaluated the improvement using a five point scale. All patients had good results in terms of improvement of skin texture, with mild and transitory side effects. This novel combined system produced improvement in wrinkles and acne scars, with progressive enhancement of skin tone and elasticity.

Early treatment using fractional CO2 laser before skin suture during scar revision surgery in Asians.

Science.gov (United States)

Du, Feiya; Yu, Yusheng; Zhou, Zhiqin; Wang, Liujia; Zheng, Shusen

2018-04-01

Fractional CO 2 laser is one of the most effective treatment options used to resurface scars. However, most previous studies have been performed on mature scars at least 2 months after surgery. Recent studies have emphasized the importance of early treatment to reduce scar formation. In the present study, we described our experience with fractional CO 2 laser intervention before skin suture during scar revision surgery in Asians, and found the treatment was safe and effective.

Upper Eyelid Fractional CO2 Laser Resurfacing With Incisional Blepharoplasty.

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Kotlus, Brett S; Schwarcz, Robert M; Nakra, Tanuj

2016-01-01

Laser resurfacing, performed at the same time as blepharoplasty, has most commonly been applied to the lower eyelid skin but can effectively be used on the upper eyelid to reduce rhytidosis and improve skin quality. The authors evaluate the safety and efficacy of this procedure. Fractional CO2 laser resurfacing was performed in conjunction with incisional upper blepharoplasty. The ultrapulsed laser energy was applied to the sub-brow skin, the upper medial canthal skin, and the pretarsal skin in 30 patients. Photos were obtained preoperatively and at 3 months. All patients demonstrated reduction in upper eyelid rhytidosis without any serious complications. Independent rhytidosis grading (0-4) showed a mean improvement of 42%. One patient experienced wound dehiscence that satisfactorily resolved without intervention. Upper eyelid laser resurfacing is effective and can be safely performed at the same time as upper blepharoplasty. This approach reduces or eliminates the need for medial incisions to address medial canthal skin redundancy and rhytidosis and it directly treats upper eyelid wrinkles on residual eyelid and infra-brow skin during blepharoplasty.

Laser treatment of amateur tattoos in Arabs in Kuwait: effectiveness and safety.

Science.gov (United States)

Qasem, Kholoud Darwish; Alotaibi, Mohammad Fehan

2012-04-01

Laser treatment of amateur tattoos on Fitzpatrick type V skin produces a considerable risk of complications because of the increased incidence of adverse pigmentary changes. The principle of selective photothermolysis predicts that the Q-switched alexandrite laser should be effective in removing tattoo ink with minimal side effects in patients with skin phototype V. To study the effectiveness of the Q-switched alexandrite (755 nm, 50 ns) laser in the treatment of amateur tattoos in Arabs in Kuwait. One hundred patients, each with multiple tattoos, were treated until total clearance. Fluences used ranged from 5 to 7 J/cm(2) with a spot size of 3 mm. Clinical evaluation was performed at baseline and at each follow-up visit until dyspigmentation resolved. Total clearing was observed in all tattoos after an average of six sessions. Both tattoo clearing and post-laser hypopigmentation (29%) and hyperpigmentation (38%) increased with higher fluences. In this prospective study, our findings suggest that the Q-switched alexandrite laser is an effective laser in removing amateur tattoos in patients with skin phototype V, but with a high incidence of pigmentary changes.

Spatiotemporal closure of fractional laser-ablated channels imaged by optical coherence tomography and reflectance confocal microscopy

DEFF Research Database (Denmark)

Banzhaf, Christina A.; Wind, Bas S.; Mogensen, Mette

2016-01-01

Background and Objective Optical coherence tomography (OCT) and reflectance confocal microscopy (RCM) offer high-resolution optical imaging of the skin, which may provide benefit in the context of laser-assisted drug delivery. We aimed to characterize postoperative healing of ablative fractional...... laser (AFXL)-induced channels and dynamics in their spatiotemporal closure using in vivo OCT and RCM techniques. Study design/Materials and Methods The inner forearm of healthy subjects (n = 6) was exposed to 10,600 nm fractional CO2 laser using 5 and 25% densities, 120 μm beam diameter, 5, 15, and 25 m......J/microbeam. Treatment sites were scanned with OCT to evaluate closure of AFXL-channels and RCM to evaluate subsequent re-epithelialization. Results OCT and RCM identified laser channels in epidermis and upper dermis as black, ablated tissue defects surrounded by characteristic hyper-and hyporeflective zones. OCT imaged...

The clinical effectiveness and cost-effectiveness of fractional CO2 laser in acne scars and skin rejuvenation: A meta-analysis and economic evaluation.

Science.gov (United States)

Ansari, Fereshteh; Sadeghi-Ghyassi, Fatemeh; Yaaghoobian, Barmak

2018-01-31

Fractional CO 2 has many indications in medicine including in treatment of acne scars and rejuvenation. The aim of this study was to evaluate the safety, efficacy, and cost-effectiveness of Fractional CO 2 Laser in comparison with other methods of rejuvenation and acne scar treatment. Several databases including Medline, OVID, EMBASE, CINHAL, SCOPUS, Web of science, CRD, and Cochrane were searched. After conducting the search and evaluation of selected publications, critical appraisal was done and eligible studies were accepted for inclusion in the systematic review. From 2667 identified publications two of the trials were eligible. The effectiveness and complications of Fractional CO 2 laser were comparable with Er:YAG but Fractional CO 2 laser was 14.7% (p = 0.01) more effective than Q-Switched ND:YAG laser. Cost affectivity of this method was the same as other alternative lasers. In conclusion Fractional CO 2 laser is an effective and safe method for curing of several kinds of skin diseases. Nevertheless there was not sufficient evidence to support its advantage. This device has equal or lower price in comparison to competent technologies except for the non- fractional ablative CO 2 laser that has the same or lower price and comparable effects.

Versatility of erbium YAG laser: from fractional skin rejuvenation to full-field skin resurfacing.

Science.gov (United States)

Holcomb, J David

2011-05-01

For the laser surgeon, the Er-YAG laser is an invaluable tool that delivers unsurpassed ablation efficiency, and with appropriate functionality (quasi long-pulse feature) provides sufficient tissue coagulation to remodel deep rhytids. As such, the 2940-nm wavelength is well suited for routine laser skin rejuvenation in full-field, fractional, and point-beam modes with additional benefits, including applicability to diverse skin types, short healing times, and a low likelihood of energy-related complications. Copyright © 2011 Elsevier Inc. All rights reserved.

Non-ablative fractionated laser skin resurfacing for the treatment of aged neck skin.

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Bencini, Pier Luca; Tourlaki, Athanasia; Galimberti, Michela; Pellacani, Giovanni

2015-06-01

Aging of the neck skin includes poikiloderma of Civatte, skin laxity and wrinkles. While the vascular alterations of poikiloderma of Civatte can be effectively treated with lasers or intense pulsed light, a successful treatment of dyschromia, skin laxity and wrinkles is still difficult to achieve. To evaluate the safety and efficacy of non-ablative fractional 1540 erbium glass laser for the treatment of aged neck skin, also by means of in vivo reflectance confocal microscopy (RCM). A prospective study for neck resurfacing in 18 women with aged neck skin. Six laser treatments were performed in 4-week intervals with a 1540-nm erbium-glass fiber laser. By using a 6-point grading scale, the mean score (±SD; range) at baseline was 3.6 (±1.5; 1-6) for skin dyschromia, 2.9 (±1.4; 1-6) for laxity and 3.3 (±1.3; 1-5) for wrinkles. Three months after the last laser session, we found a significant clinical improvement of dyschromia (p = 0.0002; Wilcoxon test), and wrinkles (p = 0.0004; Wilcoxon test), with a mean (±SD) reduction of 2.5 (±1.0) and 1.9 (±1.1) points in the 6-point grading scale, respectively. No change was observed in laxity. These results were also supported by structural changes documented by RCM. Non-ablative fractional 1540 erbium glass laser was both safe and effective for the treatment of dyschromia and wrinkles, but not effective for the laxity of the neck skin.

Efficacy and safety of 10,600-nm carbon dioxide fractional laser on facial skin with previous volume injections

Directory of Open Access Journals (Sweden)

Josiane Hélou

2013-01-01

Full Text Available Background: Fractionated carbon dioxide (CO 2 lasers are a new treatment modality for skin resurfacing. The cosmetic rejuvenation market abounds with various injectable devices (poly-L-lactic acid, polymethyl-methacrylate, collagens, hyaluronic acids, silicone. The objective of this study is to examine the efficacy and safety of 10,600-nm CO 2 fractional laser on facial skin with previous volume injections. Materials and Methods: This is a retrospective study including 14 patients treated with fractional CO 2 laser and who have had previous facial volume restoration. The indication for the laser therapy, the age of the patients, previous facial volume restoration, and side effects were all recorded from their medical files. Objective assessments were made through clinical physician global assessment records and improvement scores records. Patients′ satisfaction rates were also recorded. Results: Review of medical records of the 14 patients show that five patients had polylactic acid injection prior to the laser session. Eight patients had hyaluronic acid injection prior to the laser session. Two patients had fat injection, two had silicone injection and one patient had facial thread lift. Side effects included pain during the laser treatment, post-treatment scaling, post-treatment erythema, hyperpigmentation which spontaneously resolved within a month. Concerning the previous facial volume restoration, no granulomatous reactions were noted, no facial shape deformation and no asymmetry were encountered whatever the facial volume product was. Conclusion: CO 2 fractional laser treatments do not seem to affect facial skin which had previous facial volume restoration with polylactic acid for more than 6 years, hyaluronic acid for more than 0.5 year, silicone for more than 6 years, or fat for more than 1.4 year. Prospective larger studies focusing on many other variables (skin phototype, injected device type are required to achieve better

Fractional Ablative Laser Followed by Transdermal Acoustic Pressure Wave Device to Enhance the Drug Delivery of Aminolevulinic Acid: In Vivo Fluorescence Microscopy Study.

Science.gov (United States)

Waibel, Jill S; Rudnick, Ashley; Nousari, Carlos; Bhanusali, Dhaval G

2016-01-01

Topical drug delivery is the foundation of all dermatological therapy. Laser-assisted drug delivery (LAD) using fractional ablative laser is an evolving modality that may allow for a greater precise depth of penetration by existing topical medications, as well as more efficient transcutaneous delivery of large drug molecules. Additional studies need to be performed using energy-driven methods that may enhance drug delivery in a synergistic manner. Processes such as iontophoresis, electroporation, sonophoresis, and the use of photomechanical waves aid in penetration. This study evaluated in vivo if there is increased efficacy of fractional CO2 ablative laser with immediate acoustic pressure wave device. Five patients were treated and biopsied at 4 treatment sites: 1) topically applied aminolevulinic acid (ALA) alone; 2) fractional ablative CO2 laser and topical ALA alone; 3) fractional ablative CO2 laser and transdermal acoustic pressure wave device delivery system; and 4) topical ALA with transdermal delivery system. The comparison of the difference in the magnitude of diffusion with both lateral spread of ALA and depth diffusion of ALA was measured by fluorescence microscopy. For fractional ablative CO2 laser, ALA, and transdermal acoustic pressure wave device, the protoporphyrin IX lateral fluorescence was 0.024 mm on average vs 0.0084 mm for fractional ablative CO2 laser and ALA alone. The diffusion for the acoustic pressure wave device was an order of magnitude greater. We found that our combined approach of fractional ablative CO2 laser paired with the transdermal acoustic pressure wave device increased the depth of penetration of ALA.

The effect of a 1550 nm fractional erbium-glass laser in female pattern hair loss.

Science.gov (United States)

Lee, G-Y; Lee, S-J; Kim, W-S

2011-12-01

Female pattern hair loss (FPHL) is the most common cause of hair loss in women, and its prevalence increases with advancing age. Affected women may experience psychological distress and social withdrawal. A variety of laser and light sources have been tried for treatment of hair loss, and some success has been reported. The purpose of this study was to determine the efficacy and safety of a 1550 nm fractional erbium-glass laser in treatment of female pattern hair loss. Twenty eight ethnic South Korean patients with varying degrees of FPHL were enrolled in the study. Patients received ten treatments with a 1550 nm fractional Er:Glass Laser (Mosaic, Lutronic Co., Ltd, Seoul, South Korea) at 2-weeks intervals using the same parameters (5-10 mm tip, 6 mJ pulse energy, 800 spot/cm(2) density, static mode). Phototrichogram and global photographs were taken at baseline and at the end of laser treatment, and analysed for changes in hair density and hair shaft diameter. Global photographs underwent blinded review by three independent dermatologists using a 7-point scale. Patients also answered questionnaires assessing hair growth throughout the study. All adverse effects were reported during the study. Twenty seven patients completed a 5-month schedule of laser treatment. One patient was excluded during treatment due to occurrence of alopecia areata. At the initial visit, mean hair density was 100 ± 14/cm(2) , and mean hair thickness was 58 ± 12 μm. After 5 months of laser treatment, hair density showed a marked increase to 157 ± 28/cm(2) (P laser treatment; however, these resolved within 2 h. A 1550 nm fractional erbium-glass laser irradiation may be an effective and safe treatment option for women with female pattern hair loss. © 2011 The Authors. Journal of the European Academy of Dermatology and Venereology © 2011 European Academy of Dermatology and Venereology.

A retrospective chart review to assess the safety of nonablative fractional laser resurfacing in Fitzpatrick skin types IV to VI.

Science.gov (United States)

Clark, Charlotte M; Silverberg, Jonathan I; Alexis, Andrew F

2013-04-01

Laser resurfacing in patients with Fitzpatrick skin phototypes (SPT) IV to VI is associated with a higher risk of pigmentary alteration. There is a paucity of studies evaluating optimum treatment parameters for fractional lasers in darkly pigmented skin types. This is a retrospective review of medical records for patients with SPT IV to VI who were treated with a 1,550 nm erbium-doped fractional nonablative laser (Fraxel Re:Store SR 1550; Solta Medical, Hayword, CA). Data were collected from patient charts and the clinic laser logbook from January 2008 to January 2012. The frequency of treatment-associated postinflammatory hyperpigmentation (PIH) and treatment settings used were evaluated. A total of 115 total laser sessions (45 patients) were included in our analysis. Five of the sessions (4%) were accompanied by PIH, 2 of which occurred in a single patient. Only 1 episode of PIH lasted longer than 1 month (2 months). Two of the 5 cases had only transient PIH (≤7 days), one of which was reported by the patient and not clinically evident on examination. The 1,550 nm erbium-doped fractional laser is well tolerated in SPT IV to VI. Fractional laser resurfacing, with the settings used and pretreatment and posttreatment hydroquinone 4% cream, was associated with a low risk of PIH in darker skin types.

Fractional erbium-doped yttrium aluminum garnet laser-assisted drug delivery of hydroquinone in the treatment of melasma

Science.gov (United States)

Badawi, Ashraf M; Osman, Mai Abdelraouf

2018-01-01

Background Melasma is a difficult-to-treat hyperpigmentary disorder. Ablative fractional laser (AFL)-assisted delivery of topically applied drugs to varied targets in the skin has been an area of ongoing study and research. Objective The objective of this study was to evaluate the efficacy and safety of fractional erbium-doped yttrium aluminum garnet (Er:YAG) laser as an assisted drug delivery for enhancing topical hydroquinone (HQ) permeation into the skin of melasma patients. Patients and methods Thirty female patients with bilateral melasma were randomly treated in a split-face controlled manner with a fractional Er:YAG laser followed by 4% HQ cream on one side and 4% HQ cream alone on the other side. All patients received six laser sessions with a 2-week interval. The efficacy of treatments was determined through photographs, dermoscopic photomicrographs and Melasma Area Severity Index (MASI) score, all performed at baseline and at 12 weeks of starting therapy. The patient’s level of satisfaction was also recorded. Results Er:YAG laser + HQ showed significantly better results (plaser + HQ side vs HQ side. Minor reversible side effects were observed on both sides. Conclusion AFL-assisted delivery of HQ is a safe and effective method for the treatment of melasma. PMID:29379308

Histological evaluation of vertical laser channels from ablative fractional resurfacing: an ex vivo pig skin model.

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Skovbølling Haak, Christina; Illes, Monica; Paasch, Uwe; Hædersdal, Merete

2011-07-01

Ablative fractional resurfacing (AFR) represents a new treatment potential for various skin conditions and new laser devices are being introduced. It is important to gain information about the impact of laser settings on the dimensions of the created laser channels for obtaining a safe and efficient treatment outcome. The aim of this study was to establish a standard model to document the histological tissue damage profiles after AFR and to test a new laser device at diverse settings. Ex vivo abdominal pig skin was treated with a MedArt 620, prototype fractional carbon dioxide (CO(2)) laser (Medart, Hvidovre, Denmark) delivering single microbeams (MB) with a spot size of 165 μm. By using a constant pulse duration of 2 ms, intensities of 1-18 W, single and 2-4 stacked pulses, energies were delivered in a range from 2-144 mJ/MB. Histological evaluations included 3-4 high-quality histological measurements for each laser setting (n = 28). AFR created cone-shaped laser channels. Ablation depths varied from reaching the superficial dermis (2 mJ, median 41 μm) to approaching the subcutaneous fat (144 mJ, median 1,943 μm) and correlated to the applied energy levels in an approximate linear relation (r(2) = 0.84, p skin model to characterize AFR laser channels histologically.

Clinical efficacy of utilizing Ultrapulse CO2 combined with fractional CO2 laser for the treatment of hypertrophic scars in Asians-A prospective clinical evaluation.

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Lei, Ying; Li, Shi Feng; Yu, Yi Ling; Tan, Jun; Gold, Michael H

2017-06-01

Hypertrophic scarring is seen regularly. Tissue penetration of laser energy into hypertrophic scars using computer defaults from some lasers may be insufficient and penetration not enough. We have developed a treatment with an interrupted laser "drilling" by the Ultrapulse CO 2 (Manual Fractional Technology, MFT) and, a second pass, with fractional CO 2 . The MFT with fractional CO 2 lasers to treat hypertrophic scars is evaluated. A total of 158 patients with hypertrophic scars had three sessions of MFT with fractional CO 2 laser at 3-month intervals. Evaluations made before and 6 months after the 3rd treatment: (1) the Vancouver Scar Scale (VSS), (2) the University of North Carolina (UNC) Scar Scale, and (3) a survey of patient satisfaction. All data were analyzed using a t-test before and after treatment. The VSS score decreased from 9.35 to 3.12 (Plaser drilling by MFT and a fractional CO2 laser had profound effects on the hypertrophic scars treated. It works by increasing the penetration depth of the CO 2 laser in the scar tissue, exerting more precise effects on the hypertrophic scars. MFT combined with fractional CO 2 laser has the potential to be a major advance in the treatment of hypertrophic scars. © 2017 Wiley Periodicals, Inc.

Vehicle type affects filling of fractional laser-ablated channels imaged by optical coherence tomography

DEFF Research Database (Denmark)

Olesen, Uffe Høgh; Mogensen, Mette; Haedersdal, Merete

2017-01-01

Ablative fractional laser (AFXL) is an emerging method that enhances topical drug delivery. Penetrating the skin in microscopic, vertical channels, termed microscopic treatment zones (MTZs), the fractional technique circumvents the skin barrier and allows increased uptake of topically applied dru...... was overall greater for more superficial MTZs. In conclusion, vehicle type affects filling of MTZs, which may be of importance for AFXL-assisted drug delivery....

Risk assessment of excess drug and sunscreen absorption via skin with ablative fractional laser resurfacing : optimization of the applied dose for postoperative care.

Science.gov (United States)

Chen, Wei-Yu; Fang, Chia-Lang; Al-Suwayeh, Saleh A; Yang, Hung-Hsu; Li, Yi-Ching; Fang, Jia-You

2013-09-01

The ablative fractional laser is a new modality used for surgical resurfacing. It is expected that laser treatment can generally deliver drugs into and across the skin, which is toxicologically relevant. The aim of this study was to establish skin absorption characteristics of antibiotics, sunscreens, and macromolecules via laser-treated skin and during postoperative periods. Nude mice were employed as the animal model. The skin received a single irradiation of a fractional CO2 laser, using fluences of 4-10 mJ with spot densities of 100-400 spots/cm(2). In vitro skin permeation using Franz cells was performed. Levels of skin water loss and erythema were evaluated, and histological examinations with staining by hematoxylin and eosin, cyclooxygenase-2, and claudin-1 were carried out. Significant signs of erythema, edema, and scaling of the skin treated with the fractional laser were evident. Inflammatory infiltration and a reduction in tight junctions were also observed. Laser treatment at 6 mJ increased tetracycline and tretinoin fluxes by 70- and 9-fold, respectively. A higher fluence resulted in a greater tetracycline flux, but lower skin deposition. On the other hand, tretinoin skin deposition increased following an increase in the laser fluence. The fractional laser exhibited a negligible effect on modulating oxybenzone absorption. Dextrans with molecular weights of 4 and 10 kDa showed increased fluxes from 0.05 to 11.05 and 38.54 μg/cm(2)/h, respectively. The optimized drug dose for skin treated with the fractional laser was 1/70-1/60 of the regular dose. The skin histology and drug absorption had recovered to a normal status within 2-3 days. Our findings provide the first report on risk assessment of excessive skin absorption after fractional laser resurfacing.

Promising Option for Treatment of Striae Alba: Fractionated Microneedle Radiofrequency in Combination with Fractional Carbon Dioxide Laser

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Farahnaz Fatemi Naeini

2016-01-01

Full Text Available Background. A consistent treatment has not been proposed for treatment of Striae Alba (SA. The present study was designed to compare the fractionated microneedle radiofrequency (FMR alone and in combination with fractional carbon dioxide laser (FMR + CO2 in the treatment of SA. Methods. Forty-eight pairs of SA from six patients were selected. Right or left SAs were randomly assigned to one of the treatment groups. The surface area of the SA before and after treatment and clinical improvement using a four-point scale were measured at the baseline, after one and three months. Results. The mean age of the patients was 30.17±5.19 years. The mean difference of the surface area between pre- and posttreatment in the FMR + CO2 group was significantly higher than that in the FMR group (p=0.003. Clinical improvement scales showed significantly higher improvement in the FMR + CO2 group than in the FMR group in the first and second follow-up (p=0.002 and 0.004, resp.. There were no major persistence side-effects in both groups. Conclusions. The results showed that FMR + CO2 laser was more effective than FMR alone in the treatment of SA.

Fractional ablative CO2 laser treatment versus scar subcision and autologous fat transfer in the treatment of atrophic acne scars: New technique

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Laila Mohammad

2016-04-01

Full Text Available There are different modalities for management of atrophic acne scars which include lasers. Ablative fractional CO2 laser was developed to address the shortcomings of traditional ablative lasers, with superior results to non-ablative fractional lasers. Autologous fat transfer has been utilized for nearly a decade in tissue augmentation and reconstruction.Present studies were designed to compare ablative fractional CO2 laser treatment with scar subcision and autologous fat transfer in the treatment of atrophic acne scars. 20 patients with atrophic acne scars were recruited: 10 patients were treated by three sessions of ablative fractional CO2 laser therapy, and 10 patients treated by subcision and autologous fat transfer. All patients were followed up for three months, and were assessed by digital photograph before and after treatment through the application of Goodman and Baron quantitative and qualitative grading systems, in addition to reports by three physicians committees and reports of patients’ satisfaction. Analysis of both groups showed significant improvements in all types of atrophic acne scars. The mean percentage of total quantitative improvement was more significant in the case of autologous fat transfer with regard to ice-pick and total number of scars. Therefore, scar subcision with autologous fat transfer proved to be as effective as, or even more effective than, ablative fractional CO2 laser in the treatment of atrophic acne scars with regard to the total number of scars as well as ice-pick type.

Inflammatory responses, matrix remodeling, and re-epithelialization after fractional CO2 laser treatment of scars.

Science.gov (United States)

DeBruler, Danielle M; Blackstone, Britani N; Baumann, Molly E; McFarland, Kevin L; Wulff, Brian C; Wilgus, Traci A; Bailey, J Kevin; Supp, Dorothy M; Powell, Heather M

2017-09-01

Fractional CO 2 laser therapy has been used to improve scar pliability and appearance; however, a variety of treatment protocols have been utilized with varied outcomes. Understanding the relationship between laser power and extent of initial tissue ablation and time frame for remodeling could help determine an optimum power and frequency for laser treatment. The characteristics of initial injury caused by fractional CO 2 laser treatment, the rates of dermal remodeling and re-epithelialization, and the extent of inflammation as a function of laser stacking were assessed in this study in a porcine scar model. Full-thickness burn wounds were created on female Red Duroc pigs followed by immediate excision of the eschar and split-thickness autografting. Three months after injury, the resultant scars were treated with a fractional CO 2 laser with 70 mJ of energy delivered as either a single pulse or stacked for three consecutive pulses. Immediately prior to laser treatment and at 1, 24, 96, and 168 hours post-laser treatment, transepidermal water loss (TEWL), erythema, and microscopic characteristics of laser injury were measured. In addition, markers for inflammatory cytokines, extracellular matrix proteins, and re-epithelialization were quantified at all time points using qRT-PCR. Both treatments produced erythema in the scar that peaked 24 hours after treatment then decreased to basal levels by 168 hours. TEWL increased after laser treatment and returned to normal levels between 24 and 96 hours later. Stacking of the pulses did not significantly increase the depth of ablated wells or extend the presence of erythema. Interleukin 6 and monocyte chemoattractant protein-1 were found to increase significantly 1 hour after treatment but returned to baseline by 24 hours post laser. In contrast, expression of transforming growth factor β1 and transforming growth factor β3 increased slowly after treatment with a more modest increase than interleukin 6 and monocyte

Experimental Study of 5-fluorouracil Encapsulated Ethosomes Combined with CO2 Fractional Laser to Treat Hypertrophic Scar.

Science.gov (United States)

Zhang, Zhen; Chen, Jun; Huang, Jun; Wo, Yan; Zhang, Yixin; Chen, Xiangdong

2018-01-18

This study is designed to explore permeability of ethosomes encapsulated with 5-florouracil (5-FU) mediated by CO 2 fractional laser on hypertrophic scar tissues. Moreover, therapeutic and duration effect of CO 2 fractional laser combined with 5-FU encapsulated ethosomes in rabbit ear hypertrophic scar model will be evaluated. The permeated amount of 5-FU and retention contents of 5-FU were both determined by high-performance liquid chromatography (HPLC). Fluorescence intensities of ethosomes encapsulated with 5-FU (5E) labeled with Rodanmin 6GO (Rho) were measured by confocal laser scanning microscopy (CLSM). The permeability promotion of 5E labeled with Rho in rabbit ear hypertrophic scar mediated by CO 2 fractional laser was evaluated at 0 h, 6 h, 12 h, 24 h, 3 days and 7 days after the irradiation. The opening rates of the micro-channels were calculated according to CLSM. The therapeutic effect of 5EL was evaluated on rabbit ear hypertrophic scar in vivo. Relative thickness of rabbit ear hypertrophic scar before and after the treatment was measured by caliper method. Scar elevation index (SEI) of rabbit ear hypertrophic scar was measured using H&E staining. The data showed that the penetration amount of 5EL group was higher than 5E group (4.15 ± 2.22 vs. 0.73 ± 0.33; p 5E group (107.61 ± 13.27 vs. 20.73 ± 3.77; p 5E group (24.42 ± 4.37 vs.12.25 ± 1.64; p 5E group at different time points (1, 6, and 24 h). The opening rates of the micro-channels were decreased gradually within 24 h, and micro-channels were closed completely 3 days after the irradiation by CO 2 fractional laser. The relative thickness and SEI of rabbit ear hypertrophic scar after 7 days of treatment in the 5EL group were significantly lower than the 5E group. CO 2 fractional laser combined with topical 5E can be effective in the treatment of hypertrophic scar in vivo and supply a novel therapy method for human hypertrophic scar.

The Use of Locally Applied Vibration to Minimize Pain during Fractional CO Laser Therapy in Living Liver-Donor Scar Management

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Sinyoung Song

2016-11-01

Full Text Available BackgroundFractional CO2 laser is an effective treatment for scars, but most patients complain about sharp burning pain, even after the application of lidocaine ointment. This study analyzed the impact of a vibrating device to nonpharmacologically reduce the acute pain of laser treatment, in accordance with the gate control theory of pain management.MethodsThis is a prospective study performed from May 2013 through March 2014. Fifty-three patients (mean age, 26.7 years; range, 16–44 years who had donated livers for liver transplantation were treated with a fractional CO2 laser (10,600 nm; model eCO2, Lutronic Corp for their abdomen scars. Laser treatment was applied 4 months after surgery. A commercially available, locally applied vibrating device (model UM-30M, Unix Electronics Co. Ltd. was used, in an on-and-off pattern, together with the CO2 laser. A visual analogue scale (VAS; 0, no pain; 10, most severe pain of pain sensation was assessed and statistically analyzed using a paired t-test.ResultsThe average VAS score for pain with the vibrating device was 4.60 and the average VAS score without the vibrating device was 6.11. The average difference between scores was 1.51 (P=0.001.ConclusionsA locally applied vibrating device was demonstrated to be effective in reducing pain when treating with a fractional CO2 laser. Vibration treatment could be helpful when treating scars with fractional CO2 laser in pain-sensitive patients, particularly children.

Effect of laser welding parameters on the austenite and martensite phase fractions of NiTi

Energy Technology Data Exchange (ETDEWEB)

Oliveira, J.P., E-mail: jp.oliveira@campus.fct.unl.pt [CENIMAT/i3N, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa (Portugal); Braz Fernandes, F.M. [CENIMAT/i3N, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa (Portugal); Miranda, R.M. [UNIDEMI, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa (Portugal); Schell, N. [Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Max-Planck-Str. 1, D-21502 Geesthacht (Germany); Ocaña, J.L. [Centro Láser UPM, Universidad Politécnica de Madrid, Edificio “La Arboleda”, Ctra. Valencia, km 7,300, Campus Sur UPM, 28031 Madrid (Spain)

2016-09-15

Although laser welding is probably the most used joining technique for NiTi shape memory alloys there is still a lack of understanding about the effects of laser welding parameters on the microstructural induced changes: in both the heat affected and fusion zones martensite may be present, while the base material is fully austenitic. Synchrotron X-ray diffraction was used for fine probing laser welded NiTi joints. Through Rietveld refinement the martensite and austenite phase fractions were determined and it was observed that the martensite content increases towards the weld centreline. This is related to a change of the local transformation temperatures on these regions, which occurs due to compositional variation in those regions. The martensite phase fraction in the thermally affected regions may have significant implications on functional properties on these joints. - Highlights: •Synchrotron X-ray diffraction was used for fine probing of the microstructure in laser welded NiTi joints. •Rietveld refinement allowed to determine the content of martensite along the heat affected and fusion zones. •The martensite content increases from the base material towards the weld centreline.

Fractional CO2 laser assisted delivery of topical anesthetics: A randomized controlled pilot study

NARCIS (Netherlands)

Meesters, Arne A.; Bakker, Myrna M.; de Rie, Menno A.; Wolkerstorfer, Albert

2016-01-01

Many dermatological procedures are performed under local anesthesia. Topical anesthesia requires prolonged occlusion and is often insufficient. Infiltration anesthesia is associated with discomfort. Pretreatment with an ablative fractional laser (AFXL) may enhance penetration of topical drugs,

Rejuvenation of the male scalp using 1,927 nm non-ablative fractional thulium fiber laser.

Science.gov (United States)

Boen, Monica; Wilson, Monique J Vanaman; Goldman, Mitchel P; Wu, Douglas C

2017-07-01

The male scalp undergoes extensive photodamage due to a high prevalence of androgenic alopecia and exposure to ultraviolet radiation. This photodamage presents as solar lentigines, fine rhytides, and keratosis, and can prematurely age a patient. In this study, we demonstrate the safety and efficacy of the fractionated 1,927 nm thulium fiber laser using high density and high energy settings to achieve rejuvenation of the male scalp after a single treatment session. Four male patients with Fitzpatrick skin types II-III and extensive photodamage on the scalp underwent one treatment with the fractional non-ablative 1,927 nm thulium fiber laser. The patients had a 60-90% improvement in dyspigmentation, lentigines, and keratosis. No adverse events were observed and the patients tolerated the procedure well. This case series is the first report in the literature demonstrating the successful rejuvenation of the scalp using the 1,927 nm thulium fiber laser. Lasers Surg. Med. 49:475-479, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

A study on fractional erbium glass laser therapy versus chemical peeling for the treatment of melasma in female patients

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Neerja Puri

2013-01-01

Full Text Available Introduction: Melasma is a commonly acquired hypermelanosis and a common dermatologic skin disease that occurs on sun-exposed areas of face. Aims: To assess the efficacy and safety of non-ablative 1,550 nm Erbium glass fractional laser therapy and compare results with those obtained with chemical peeling. Materials and Methods: We selected 30 patients of melasma aged between 20 years and 50 years for the study. The patients were divided into two groups of 15 patients each. Group I patients were subjected to four sessions of 1,550 nm Erbium glass non-ablative fractional laser at 3 weeks interval. In group II patients, four sessions of chemical peeling with 70% glycolic acid was performed. Results: After 12 weeks of treatment, percentage reduction in Melasma Area and Severity Index (MASI score was seen in 62.9% in the laser group and 58.7% in the peels group. Conclusion: It was observed that 1,550 nm fractional laser is as effective as 70% glycolic acid peel in reducing MASI score in patients with melasma.

Comparative study of the efficacy of Platelet-rich plasma combined with carboxytherapy vs its use with fractional carbon dioxide laser in atrophic acne scars.

Science.gov (United States)

Al Taweel, Abdul-Aziz Ibrahim; Al Refae, Abdul-Aziz Abdul-Salam; Hamed, Ahmed Mohamed; Kamal, Asmaa Mostafa

2018-04-22

Acne scars are a major concerning problem to all acne patients affecting their quality of life. Platelet-rich plasma (PRP) and fractional CO 2 laser are innovative treatment modalities for acne scars. Carboxytherapy can also be used to improve scar tissue through the increase in collagen deposition and reorganization, and the improvement in skin texture and tone. The aim of this work was to compare the efficacy, safety, and complications of the intradermal injection of PRP combined with carboxytherapy and PRP combined with fractional CO 2 laser, in the treatment of atrophic acne scars. Forty patients with atrophic acne scars were divided into 2 groups. Group A included 20 patients and was subjected to three fractional CO 2 laser sessions combined with PRP injection. Group B included 20 patients and was subjected to three sessions of carboxytherapy combined with PRP injection. Both fractional CO 2 laser and carboxytherapy combined with PRP showed improvement in acne scars and patients' satisfaction but the improvement with fractional CO 2 laser was significantly better than carboxytherapy but with more side effects. Improvement of acne scars was noted in both treatment modalities with obvious higher and statistically significant results in favor of fractional CO 2 laser but with more side effects. Carboxytherapy is a promising tool in treatment of acne scars with less complication. © 2018 Wiley Periodicals, Inc.

Comparison of the Effectiveness of Ablative and Non-Ablative Fractional Laser Treatments for Early Stage Thyroidectomy Scars

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Jin-Uk Jang

2016-11-01

Full Text Available BackgroundOpen thyroidectomy is conventionally performed at the anterior side of neck, which is a body part with a comparatively great degree of open exposure; due to this, postoperative scarring may cause distress in patients. We aimed to compare the effects of ablative and nonablative fractional laser treatments on thyroidectomy scars. We examined medical records in a retrospective manner and analyzed scars based on their digital images by using the modified Manchester Scar Scale (mMSS.MethodsBetween February 2012 and May 2013, 55 patients with thyroidectomy scars were treated with ablative (34 patients or nonablative (21 patients fractional laser. Each patient underwent 4 laser treatment sessions in 3–4 week intervals, 1–2 months postoperatively. Scar improvement was assessed using patient images and the mMSS scale.ResultsThe mean decrease in scar score was 3.91 and 3.47 in the ablative and nonablative groups, respectively; the reduction between 2 groups did not exhibit any significant difference (P=0.16. We used the scale once again to individually evaluate scar attributes. The nonablative group accounted for a considerably higher color score value (P=0.03; the ablative group accounted for a considerably higher contour score value (P<0.01. Patient satisfaction was high and no complications occurred.ConclusionsBoth types of fractional laser treatments can be used successfully for thyroidectomy scar treatment with minimal complications; however, results indicate that higher effectiveness may be obtained from the use of ablative and nonablative lasers for hypertrophic scars and early erythematous scars, respectively. Therefore, the appropriate laser for scar treatment should be selected according to its specific characteristics.

Delivery of Methotrexate and Characterization of Skin Treated by Fabricated PLGA Microneedles and Fractional Ablative Laser.

Science.gov (United States)

Nguyen, Hiep X; Banga, Ajay K

2018-02-21

This study investigated in vitro transdermal delivery of methotrexate through dermatomed porcine ear and cadaver human skin treated with poly (D,L-lactide-co-glycolide) acid microneedles or fractional ablative laser. PLGA microneedles were fabricated and characterized using scanning electron microscopy and mechanical assessment techniques. The integrity of treated skin was evaluated by rheometer, transepidermal water loss, and skin electrical resistance measurements. Successful skin microporation was demonstrated by dye binding, histology, pore uniformity, confocal laser microscopy, and DermaScan studies. In vitro permeation experiment was performed on Franz diffusion cells to determine drug delivery into and across the skin. Both physical treatments resulted in a considerable decrease in skin resistance and an increase in transepidermal water loss value. The laser-created microchannels were significantly larger than those formed by microneedles (p < 0.05). An effective force of 41.04 ± 18.33 N was required to achieve 100% penetration efficiency of the microneedles. For both porcine ear and human skin, laser ablation provided a significantly higher methotrexate permeability into the receptor chamber and skin layers compared to microneedle poration and untreated skin (p < 0.05). Both fractional ablative laser and polymeric microneedles markedly enhanced in vitro transdermal delivery of methotrexate into and across skin. Graphical Abstract ᅟ.

Laser Treatment of Tattoos: Basic Principles.

Science.gov (United States)

Bäumler, Wolfgang

2017-01-01

Tattooing has become very popular worldwide during the past decades, and millions of people have one or many tattoos at different anatomical sites. The color of tattoos is mainly black, followed by red, green, blue, and other colors. A part of the tattooed people regret tattooing or have permanent problems with tattoos and therefore seek for tattoo removal. Tattoos consist of solid pigment particles in the skin. Thus, tattoo removal requires fragmentation of these permanently incorporated particles. The gold standard of tattoo removal is laser therapy. Short light pulses at high intensities are applied to the tattooed skin surface. The laser light penetrates the skin and is selectively absorbed in the pigment particles. The absorbed laser light leads to heat-up and fragmentation of the particles. Due to the complex chemistry of the various tattoo pigments, the efficacy of this fragmentation process is frequently unpredictable. Due to the short and intense pulses, nonlinear effects of light and thermal properties of tattoo particles may play a role, and the assumptions of selective photothermolysis may not reflect the real process of tattoo particle fragmentation as a whole. In case fragmentation occurs, the concentration of pigment particles in the skin decreases, yielding a fading of the tattoo color in the skin. Laser therapy is most effective in black tattoos and less effective for colored tattoos. The rate of side effects is low due to the selectivity of the treatment. Laser light may change the chemistry of the tattoo pigments and hence provoke toxic decomposition products. © 2017 S. Karger AG, Basel.

Fractional non-ablative laser-assisted drug delivery leads to improvement in male and female pattern hair loss.

Science.gov (United States)

Bertin, Ana Carina Junqueira; Vilarinho, Adriana; Junqueira, Ana Lúcia Ariano

2018-02-16

Androgenetic alopecia, also known as male and female pattern hair loss, is a very prevalent condition; however, approved therapeutic options are limited. Fractionated laser has been proposed to assist in penetration of topical medications to the cutaneous tissue. We present four cases of androgenetic alopecia that underwent treatment with a non-ablative erbium glass fractional laser followed by the application of topical finasteride 0,05% and growth factors including basic fibroblast growth factor, insulin-like growth factor, vascular endothelial growth factor, and copper peptide 1%. During all laser treatment sessions, eight passes were performed, at 7 mJ, 3-9% of coverage and density of 120 mzt/cm 2 . A positive response was observed in all of the four patients. Photographs taken 2 weeks after the last session showed improvement in hair regrowth and density. No significant side effects were observed.

The comparison of skin rejuvenation effects of vitamin A, fractional laser, and their combination on rat.

Science.gov (United States)

Qu, Yan; Wang, Ying; Zhang, Yan; Han, Chunyu; Gao, Dong; Jin, Waishu; Liang, Jinning; Xia, Xiujuan

2018-03-15

Because of long-term exposure of skin, skin aging is an unavoidable natural law with age. Traditional Vitamin A and novel ablative fractional laser technique both have the effects of skin rejuvenation, and studies have demonstrated both of them have apparent clinical efficacy and histology-improving effects on photo-aging skin. 45 female healthy Wistar rats were selected and the depilation areas of every rat were divided into four regions: control region(Region A), Vitamin A acid region(Region B), combination treatment region(Region C), and fractional laser region(Region D). 0.025% Vitamin A acid cream was applied to Region B and C every day for 3 weeks; Region C and D were irradiated once with 10600nm CO 2 fractional laser on the first day of the trail. The skin tissue was dissected and placed into liquid nitrogen according to the design. The real-time quantitative PCR and western blotting methods were taken to detect the expression changes of miR-29a, Akt, TGF-β, and mRNA of type III pre-collagen. It can be seen from the results of the real-time quantitative PCR that the mRNA expression levels of type III pre-collagen, Akt, and TGF-β in the treatment regions are up-regulated and the expression levels of miR-29a mRNA are down-regulated compared to the Region A. The hybridization tests showed that changes of the expression of type III pre-collagen, Akt gene, miR-29a gene, and TGF-β gene across the experiment regions are all significantly different in the third week, and the expression levels of them all achieve the highest value in the third week, the expression level of miR-29a gene achieves the lowest value in the third week, which are consistent with the results of real-time quantitative PCR. It is indicated that the combination region of Vitamin A acid and fractional laser may lead to low expression of miR-29a, thus the inhibition of downstream Akt activation is loss, Akt activation is enhanced, enhancement of the expression of TGF-β is induced, leading to

Ablative fractional lasers (CO(2) and Er:YAG): a randomized controlled double-blind split-face trial of the treatment of peri-orbital rhytides.

Science.gov (United States)

Karsai, Syrus; Czarnecka, Agnieszka; Jünger, Michael; Raulin, Christian

2010-02-01

Ablative fractional lasers were introduced for treating facial rhytides in an attempt to achieve results comparable to traditional ablative resurfacing but with fewer side effects. However, there is conflicting evidence on how well this goal has generally been achieved as well as on the comparative value of fractional CO(2) and Er:YAG lasers. The present study compares these modalities in a randomized controlled double-blind split-face study design. Twenty-eight patients were enrolled and completed the entire study. Patients were randomly assigned to receive a single treatment on each side of the peri-orbital region, one with a fractional CO(2) and one with a fractional Er:YAG laser. The evaluation included the profilometric measurement of wrinkle depth, the Fitzpatrick wrinkle score (both before and 3 months after treatment) as well as the assessment of side effects and patient satisfaction (1, 3, 6 days and 3 months after treatment). Both modalities showed a roughly equivalent effect. Wrinkle depth and Fitzpatrick score were reduced by approximately 20% and 10%, respectively, with no appreciable difference between lasers. Side effects and discomfort were slightly more pronounced after Er:YAG treatment in the first few days, but in the later course there were more complaints following CO(2) laser treatment. Patient satisfaction was fair and the majority of patients would have undergone the treatment again without a clear preference for either method. According to the present study, a single ablative fractional treatment session has an appreciable yet limited effect on peri-orbital rhytides. When fractional CO(2) and Er:YAG lasers are used in such a manner that there are comparable post-operative healing periods, comparable cosmetic improvement occurs. Multiple sessions may be required for full effect, which cancels out the proposed advantage of fractional methods, that is, fewer side effects and less down time.

A three-temperature model of selective photothermolysis for laser treatment of port wine stain containing large malformed blood vessels

International Nuclear Information System (INIS)

Li, D.; Wang, G.X.; He, Y.L.; Wu, W.J.; Chen, B.

2014-01-01

As congenital vascular malformations, port wine stain (PWS) is composed of ectatic venular capillary blood vessels buried within healthy dermis. In clinic, pulsed dye laser (PDL) in visible band (e.g. 585 nm) together with cryogen spray cooling (CSC) have become the golden standard for treatment of PWS. However, due to the limited energy deposition of the PDL in blood, large blood vessels are likely to survive from the laser irradiation. As a result, complete clearance of the lesions is rarely achieved. Assuming the local thermal non-equilibrium in skin tissue during the laser surgery, a three-temperature model is proposed to treat the PWS tissue as a porous media composed of a non-absorbing dermal matrix buried with the blood as well as the large malformed blood vessels. Three energy equations are constructed and solved coupling for the temperature of the blood in average-sized PWS vessels, non-absorbing dermal tissues and large malformed blood vessels, respectively. Subsequently, the thermal responses of human skin to visible (585 nm) and near-infrared (1064 nm) laser irradiations with various pulse durations in conjunction with cryogen spray cooling are investigated by the new model, and Arrhenius integral is used to analyze the thermal damage. The simulations show that the short pulse duration of 1.5 ms results in a higher selective heating of blood over epidermis, which will lead to a desired clinic outcome than the longer pulse duration. Due to a much deeper light penetration depth, laser irradiation with 1064 nm in wavelength is superior to that with 585 nm in treating patients with cutaneous hyper-vascular malformation. Complete coagulations are predicted in large-sized and deeply extending blood vessels by 1064 nm laser. - Highlights: •A three-temperature model is proposed for the laser treatment of port wine stain (PWS). •Average sized and large malformed blood vessels in porous medium (tissue) are considered. •Thermal responses of PWS to

Laser-induced breakdown spectroscopy measurement of a small fraction of rhenium in bulk tungsten

Science.gov (United States)

Nishijima, D.; Ueda, Y.; Doerner, R. P.; Baldwin, M. J.; Ibano, K.

2018-03-01

Laser-induced breakdown spectroscopy (LIBS) of bulk rhenium (Re) and tungsten (W)-Re alloy has been performed using a Q-switched Nd:YAG laser (wavelength = 1064 nm, pulse width ∼4-6 ns, laser energy = 115 mJ). It is found that the electron temperature, Te, of laser-induced Re plasma is lower than that of W plasma, and that Te of W-Re plasma is in between Re and W plasmas. This indicates that material properties affect Te in a laser-induced plasma. For analysis of W-3.3%Re alloy, only the strongest visible Re I 488.9 nm line is found to be used because of the strong enough intensity without contamination with W lines. Using the calibration-free LIBS method, the atomic fraction of Re, cRe, is evaluated as a function of the ambient Ar gas pressure, PAr. At PAr 10 Torr due to spectral overlapping of the Re I 488.9 nm line by an Ar II 488.9 nm line.

Fractional laser microablation of skin aimed at enhancing its permeability for nanoparticles

International Nuclear Information System (INIS)

Genina, Elina A; Dolotov, L E; Bashkatov, A N; Terentyuk, G S; Maslyakova, G N; Zubkina, E A; Tuchin, Valerii V; Yaroslavsky, I V; Altshuler, G B

2011-01-01

A new method for delivering nanoparticles into the skin using the fractional laser microablation of its surface and the ultrasonic treatment is proposed. As a result of in vitro and in vivo studies, it is shown that the 290-nm laser pulses with the energy from 0.5 to 3.0 J provide the penetration of nanoparticles of titanium dioxide with the diameter ∼100 nm from the skin surface to the depth, varying from 150 to 400 μm. Histological testing of the skin areas, subjected to the treatment, shows that the particles stay in the dermis at the depth up to 400 μm no less than for three weeks. (optical technologies in biophysics and medicine)

Fractional nonablative 1,540-nm laser resurfacing of atrophic acne scars. A randomized controlled trial with blinded response evaluation

DEFF Research Database (Denmark)

Hedelund, Lene; Moreau, Karen Estell R; Beyer, Ditte M

2010-01-01

The efficacy of nonablative fractional laser resurfacing of acne scars has been described in case reports and uncontrolled trials. The present study is the first randomized controlled trial in this field. The aim of this study was to examine the efficacy and adverse effects of 1,540-nm nonablative...... fractional laser treatment of acne scars. Ten patients with acne scars were included. Two intraindividual areas of similar size and appearance within contralateral anatomical regions were randomized to (1) 3-monthly laser treatments with a StarLux 1,540-nm fractional handpiece, and (2) no treatment. Blinded...... appeared more even and smooth than untreated control areas (4.5, 2-6.5, versus 6.5, 4.5-8, P=0.0156, at 4 weeks; 4.5, 2.5-6.5, versus 6.5, 4.5-8, at 12 weeks; P=0.0313). Patients were satisfied with the treatment (5.5, 1-7, after 12 weeks) and five of the ten patients evaluated their acne scars...

Fractional carbon dioxide laser versus low-dose UVA-1 phototherapy for treatment of localized scleroderma: a clinical and immunohistochemical randomized controlled study.

Science.gov (United States)

Shalaby, S M; Bosseila, M; Fawzy, M M; Abdel Halim, D M; Sayed, S S; Allam, R S H M

2016-11-01

Morphea is a rare fibrosing skin disorder that occurs as a result of abnormal homogenized collagen synthesis. Fractional ablative laser resurfacing has been used effectively in scar treatment via abnormal collagen degradation and induction of healthy collagen synthesis. Therefore, fractional ablative laser can provide an effective modality in treatment of morphea. The study aimed at evaluating the efficacy of fractional carbon dioxide laser as a new modality for the treatment of localized scleroderma and to compare its results with the well-established method of UVA-1 phototherapy. Seventeen patients with plaque and linear morphea were included in this parallel intra-individual comparative randomized controlled clinical trial. Each with two comparable morphea lesions that were randomly assigned to either 30 sessions of low-dose (30 J/cm 2 ) UVA-1 phototherapy (340-400 nm) or 3 sessions of fractional CO 2 laser (10,600 nm-power 25 W). The response to therapy was then evaluated clinically and histopathologically via validated scoring systems. Immunohistochemical analysis of TGF-ß1 and MMP1 was done. Patient satisfaction was also assessed. Wilcoxon signed rank test for paired (matched) samples and Spearman rank correlation equation were used as indicated. Comparing the two groups, there was an obvious improvement with fractional CO 2 laser that was superior to that of low-dose UVA-1 phototherapy. Statistically, there was a significant difference in the clinical scores (p = 0.001), collagen homogenization scores (p = 0.012), and patient satisfaction scores (p = 0.001). In conclusion, fractional carbon dioxide laser is a promising treatment modality for cases of localized morphea, with proved efficacy of this treatment on clinical and histopathological levels.

Combination of Q-switched and quasi long-pulsed 1064-nm Nd:YAG laser, non-ablative 1450-nm diode laser, and ablative 10 600-nm carbon dioxide fractional laser for enlarged pores.

Science.gov (United States)

Cho, Sung Bin; Noh, Seongmin; Lee, Sang Ju; Kang, Jin Moon; Kim, Young Koo; Lee, Ju Hee

2010-07-01

Currently, there is no gold standard for the treatment of enlarged facial pores. In this report, we describe a patient with enlarged nasal pores which were treated with a combination of a non-ablative 1450-nm diode laser, a Q-switched and quasi long-pulsed 1064-nm Nd:YAG laser, and an ablative 10 600-nm carbon dioxide fractional laser system. Four months after the final treatment, the condition of the patient's pores had markedly improved, and the patient was satisfied with the results.

Treatment of striae distensae with needling therapy versus CO2 fractional laser.

Science.gov (United States)

Khater, Mohamed H; Khattab, Fathia M; Abdelhaleem, Manal R

2016-01-01

Striae are atrophic dermal scars with overlying epidermal atrophy causing cosmetic concern. This study assesses and compares the efficacy and safety of needling therapy versus CO2 fractional laser in treatment of striae. Twenty Egyptian female patients with striae in the abdomen and lower limbs were involved in the study. The patients were treated with needling therapy and CO2 laser every 1 month for 3 sessions. Follow-up by digital photography and skin biopsy was conducted at baseline and 6 months after treatment. Clinical improvement was assessed by comparing photographs and patient's satisfaction before and after treatment. Nine of 10 (90%) needle-treated patients showed improvement. Among them, 3 (30%) had good, 4 (40%) had fair, and 2 (20%) had poor improvements; however, 1 (10%) did not show any improvement after the treatment. In CO2-laser treated patients, 5 of 10 (50%) of the patients showed clinical improvement; 1 (10%) were good, 3 (30%) were fair, and 1 (10%) were poor; however, 5 (50%) did not show improvement. The results support the use of microneedle therapy over CO2 lasers for striae treatment.

The Clinical Efficacy of Autologous Platelet-Rich Plasma Combined with Ultra-Pulsed Fractional CO2 Laser Therapy for Facial Rejuvenation.

Science.gov (United States)

Hui, Qiang; Chang, Peng; Guo, Bingyu; Zhang, Yu; Tao, Kai

2017-02-01

Ultra-pulsed fractional CO 2 laser is an efficient, precise, and safe therapeutic intervention for skin refreshing, although accompanied with prolonged edema and erythema. In recent years, autologous platelet-rich plasma (PRP) has been proven to promote wound and soft tissue healing and collagen regeneration. To investigate whether the combination of PRP and ultra-pulsed fractional CO 2 laser had a synergistic effect on therapy for facial rejuvenation. Totally, 13 facial aging females were treated with ultra-pulsed fractional CO 2 laser. One side of the face was randomly selected as experimental group and injected with PRP, the other side acted as the control group and was injected with physiological saline at the same dose. Comprehensive assessment of clinical efficacy was performed by satisfaction scores, dermatologists' double-blind evaluation and the VISIA skin analysis system. After treatment for 3 months, subjective scores of facial wrinkles, skin texture, and skin elasticity were higher than that in the control group. Similarly, improvement of skin wrinkles, texture, and tightness in the experimental group was better compared with the control group. Additionally, the total duration of erythema, edema, and crusting was decreased, in the experimental group compared with the control group. PRP combined with ultra-pulsed fractional CO 2 laser had a synergistic effect on facial rejuvenation, shortening duration of side effects, and promoting better therapeutic effect.

Combination of platelet rich plasma in fractional carbon dioxide laser treatment increased clinical efficacy of for acne scar by enhancement of collagen production and modulation of laser-induced inflammation.

Science.gov (United States)

Min, Seonguk; Yoon, Ji Young; Park, Seon Yong; Moon, Jungyoon; Kwon, Hyuck Hoon; Suh, Dae Hun

2018-04-01

Platelet-rich plasma (PRP) which contains large amounts of growth factors has been tried to enhance therapeutic efficacy of laser treatment for acne scar with unknown underlying mechanism. The present study was conducted to investigate the molecular mechanism of increased clinical efficacy of PRP when combined with fractional laser treatment for treating acne scars. Subjects with mild to moderate acne scars were treated with two sessions of fractional CO 2 laser therapy given with and without co-administration of PRP. Skin biopsy specimens were obtained at baseline, 1, 3, 7, and 28 days for investigation of molecular profiles associated with skin changes produced by laser plus PRP treatment. The PRP treatment increased clinical efficacy with decreased severity of adverse effects such as erythema, swelling and oozing. Productions of TGFβ1 and TGFβ3 proteins were more highly elevated on the PRP-treated side of the face compared to the control side at day 28. Furthermore, PRP-treated side showed significant increase of c-myc, TIMP, and HGF expression. Experimental fibroblast culture model was also used. PRP administration after laser irradiation increased expressions of p-Akt, TGFβ1, TGFβ3, β-catenin, collagen 1, and collagen 3 in both dose-dependent and time dependent manners in fibroblast. Moreover, we acquired clinical and histological data through randomized control clinical trial. Taken together with human study results combined with the data from cell experiments we suggest that PRP treatment increased fibrogenetic molecules induced by fractional CO 2 laser, which have association with clinical effect. Lasers Surg. Med. 50:302-310, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Image-guided automatic triggering of a fractional CO2 laser in aesthetic procedures.

Science.gov (United States)

Wilczyński, Sławomir; Koprowski, Robert; Wiernek, Barbara K; Błońska-Fajfrowska, Barbara

2016-09-01

Laser procedures in dermatology and aesthetic medicine are associated with the need for manual laser triggering. This leads to pulse overlapping and side effects. Automatic laser triggering based on image analysis can provide a secure fit to each successive doses of radiation. A fractional CO2 laser was used in the study. 500 images of the human skin of healthy subjects were acquired. Automatic triggering was initiated by an application together with a camera which tracks and analyses the skin in visible light. The tracking algorithm uses the methods of image analysis to overlap images. After locating the characteristic points in analysed adjacent areas, the correspondence of graphs is found. The point coordinates derived from the images are the vertices of graphs with respect to which isomorphism is sought. When the correspondence of graphs is found, it is possible to overlap the neighbouring parts of the image. The proposed method of laser triggering owing to the automatic image fitting method allows for 100% repeatability. To meet this requirement, there must be at least 13 graph vertices obtained from the image. For this number of vertices, the time of analysis of a single image is less than 0.5s. The proposed method, applied in practice, may help reduce the number of side effects during dermatological laser procedures resulting from laser pulse overlapping. In addition, it reduces treatment time and enables to propose new techniques of treatment through controlled, precise laser pulse overlapping. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fractional CO2 laser resurfacing of photoaged facial and non-facial skin: histologic and clinical results and side effects.

Science.gov (United States)

Sasaki, Gordon H; Travis, Heather M; Tucker, Barbara

2009-12-01

CO(2) fractional ablation offers the potential for facial and non-facial skin resurfacing with minimal downtime and rapid recovery. The purpose of this study was (i) to document the average depths and density of adnexal structures in non-lasered facial and non-facial body skin; (ii) to determine injury in ex vivo human thigh skin with varying fractional laser modes; and (iii) to evaluate the clinical safety and efficacy of treatments. Histologies were obtained from non-lasered facial and non-facial skin from 121 patients and from 14 samples of excised lasered thigh skin. Seventy-one patients were evaluated after varying energy (mJ) and density settings by superficial ablation, deeper penetration, and combined treatment. Skin thickness and adnexal density in non-lasered skin exhibited variable ranges: epidermis (47-105 mum); papillary dermis (61-105 mum); reticular dermis (983-1986 mum); hair follicles (2-14/ HPF); sebaceous glands (2-23/HPF); sweat glands (2-7/HPF). Histological studies of samples from human thigh skin demonstrated that increased fluencies in the superficial, deep and combined mode resulted in predictable deeper levels of ablations and thermal injury. An increase in density settings results in total ablation of the epidermis. Clinical improvement of rhytids and pigmentations in facial and non-facial skin was proportional to increasing energy and density settings. Patient assessments and clinical gradings by the Wilcoxon's test of outcomes correlated with more aggressive settings. Prior knowledge of normal skin depths and adnexal densities, as well as ex vivo skin laser-injury profiles at varying fluencies and densities, improve the safety and efficiency of fractional CO(2) for photorejuvenation of facial and non-facial skin.

Trial of human laser epilation technology for permanent wool removal in Merino sheep.

Science.gov (United States)

Colditz, I G; Cox, T; Small, A H

2015-01-01

To assess whether human laser epilation technology can permanently prevent wool growth in sheep. An observational study. Two commercial human epilation lasers (Sharplan alexandrite 755 nm laser, and Lumenis LightSheer 800 nm diode laser) were tested at energies between 10 and 100 J/cm2 and pulse widths from 2 to 400 ms. Wool was clipped from flank, breech, pizzle and around the eyes of superfine Merino sheep with Oster clippers. After initial laser removal of residual wool to reveal bare skin, individual skin sites were treated with up to 15 cycles of laser irradiation. Behavioural responses during treatment, skin temperature immediately after treatment and skin and wool responses for 3 months after treatment were monitored. A clear transudate was evident on the skin surface within minutes. A dry superficial scab developed by 24 h and remained adherent for at least 6 weeks. When scabs were shed, there was evidence of scarring at sites receiving multiple treatment cycles and normal wool growth in unscarred skin. There was no evidence of laser energy level or pulse width affecting the response of skin and wool to treatment and no evidence of permanent inhibition of wool growth by laser treatment. Laser treatment was well tolerated by the sheep. Treatment of woolled skin with laser parameters that induce epilation by selective photothermolysis in humans failed to induce permanent inhibition of wool growth in sheep. Absence of melanin in wool may have contributed to the result. © 2015 Australian Veterinary Association.

The effect of fractional CO2 laser irradiation on remineralization of enamel white spot lesions.

Science.gov (United States)

Poosti, Maryam; Ahrari, Farzaneh; Moosavi, Horieh; Najjaran, Hoda

2014-07-01

This study investigated the combined effect of fractional CO(2) laser irradiation and fluoride on treatment of enamel caries. Sixty intact premolars were randomly assigned into four groups and then stored in a demineralizing solution to induce white spot lesions. Tooth color was determined at baseline (T1) and after demineralization (T2). Afterwards, the teeth in group 1 remained untreated (control), while group 2 was exposed to an acidulated phosphate fluoride (APF) gel for 4 min. In groups 3 and 4, a fractional CO(2) laser was applied (10 mJ, 200 Hz, 10 s) either before (group 3) or through (group 4) the APF gel. The teeth were then immersed in artificial saliva for 90 days while subjected to daily fluoride mouthrinse and weekly brushing. Color examinations were repeated after topical fluoride application (T3) and 90 days later (T4). Finally, the teeth were sectioned, and microhardness was measured at the enamel surface and at 30 and 60 μ from the surface. In both lased groups, the color change between T1 and T4 stages (∆E(T1-T4)) was significantly lower than those of the other groups (p Laser irradiation followed by fluoride application (group 3) caused a significant increase in surface microhardness compared to APF alone and control groups (p laser before fluoride therapy is suggested for recovering the color and rehardening of demineralized enamel.

The Efficacy and Safety of Ablative Fractional Resurfacing Using a 2,940-Nm Er:YAG Laser for Traumatic Scars in the Early Posttraumatic Period

Directory of Open Access Journals (Sweden)

Sun Goo Kim

2012-05-01

Full Text Available BackgroundSkin injuries, such as lacerations due to trauma, are relatively common, and patients are very concerned about the resulting scars. Recently, the use of ablative and non-ablative lasers based on the fractional approach has been used to treat scars. In this study, the authors demonstrated the efficacy and safety of ablative fractional resurfacing (AFR for traumatic scars using a 2,940-nm erbium: yttrium-aluminum-garnet (Er:YAG laser for traumatic scars after primary repair during the early posttraumatic period.MethodsTwelve patients with fifteen scars were enrolled. All had a history of facial laceration and primary repair by suturing on the day of trauma. Laser therapy was initiated at least 4 weeks after the primary repair. Each patient was treated four times at 1-month intervals with a fractional ablative 2,940-nm Er:YAG laser using the same parameters. Post-treatment evaluations were performed 1 month after the fourth treatment session.ResultsAll 12 patients completed the study. After ablative fractional laser treatment, all treated portions of the scars showed improvements, as demonstrated by the Vancouver Scar Scale and the overall cosmetic scale as evaluated by 10 independent physicians, 10 independent non-physicians, and the patients themselves.ConclusionsThis study shows that ablative fractional Er:YAG laser treatment of scars reduces scars fairly according to both objective results and patient satisfaction rates. The authors suggest that early scar treatment using AFR can be one adjuvant scar management method for improving the quality of life of patients with traumatic scars.

Muscle relaxation for individuals having tattoos removed through laser treatment: possible effects regarding anxiety and pain.

Science.gov (United States)

Huang, Faye; Chou, Wen-Jiun; Chen, Tien-Hsing; Chen, Ching; Hsieh, Yu-Lian; Chong, Mian-Yoon; Hung, Chi-Fa; Lin, Shu-Ching; Tsai, Hsiu-Huang; Wang, Liang-Jen

2016-08-01

Effectively managing pain is vital for the well-being and satisfaction of patients undergoing dermatologic treatments involving lasers. This study investigates the potential outcome of using muscle relaxation techniques to reduce pain among people having their tattoos removed with laser treatment. This study consists of 56 participants (mean age 18.1 ± 2.1 years) that had tattoos removed using the principle of selective photothermolysis. These participants underwent muscle relaxation before receiving the laser treatment. Their peripheral skin temperatures (PST) were measured both at the beginning and the end of the muscle relaxation period. Then, the Beck Anxiety Inventory was applied to evaluate anxiety levels. Once the laser treatment was completed, pain levels were measured using a visual analogue scale. A total of 125 person-sessions of laser treatment and psychometric assessments were performed in this study. The muscle relaxation method significantly increased the PST of the participants while reducing the levels of anxiety and pain throughout the course of the laser treatment procedure. The PST, anxiety scores, and pain scores all showed significant correlations with one another. According to the results obtained, this study proposes that muscle relaxation techniques be considered possibly auxiliary treatment options for individuals having tattoos removed through laser treatment. Additional studies with a comparison group and a larger sample size are required in the future to confirm the effectiveness of such intervention.

Novel methotrexate soft nanocarrier/fractional erbium YAG laser combination for clinical treatment of plaque psoriasis.

Science.gov (United States)

Ramez, Shahenda A; Soliman, Mona M; Fadel, Maha; Nour El-Deen, Faisal; Nasr, Maha; Youness, Eman R; Aboel-Fadl, Dalea M

2018-02-15

Psoriasis is a commonly encountered chronic dermatological disease, presenting with inflammatory symptoms in patients. Systemic treatment of psoriasis is associated with several adverse effects, therefore the development of a customized topical treatment modality for psoriasis would be an interesting alternative to systemic delivery. The therapeutic modality explored in this article was the comparative treatment of psoriatic patients using nanoparticulated methotrexate in the form of jojoba oil-based microemulsion with or without fractional erbium YAG laser. Assessment parameters included follow-up photography for up to 8 weeks of treatment, estimation of the psoriasis severity [TES (thickness, erythema, scales)] score, and histopathological skin evaluation. The prepared methotrexate microemulsion was clinically beneficial and safe in treatment of psoriasis vulgaris. The concomitant use of the fractional laser provided improvement in the psoriatic plaques within shorter time duration (3 weeks compared to 8 weeks of treatment), presenting an alternative topical treatment modality for psoriasis vulgaris.

Structural characterization on in vitro porcine skin treated by ablative fractional laser using optical coherence tomography

Science.gov (United States)

Feng, Kairui; Zhou, Kanheng; Ling, Yuting; O'Mahoney, Paul; Ewan, Eadie; Ibbotson, Sally H.; Li, Chunhui; Huang, Zhihong

2018-02-01

Ablative fractional skin laser is widely applied for various skin conditions, especially for cosmetic repairing and promoting the located drug delivery. Although the influence of laser treatment over the skin has been explored before in means of excision and biopsy with microscopy, these approaches are invasive, only morphological and capable of distorting the skin. In this paper the authors use fresh porcine skin samples irradiated by the lasers, followed by detected by using Optical Coherence Tomography (OCT). This advanced optical technique has the ability to present the high resolution structure image of treated sample. The results shows that laser beams can produce holes left on the surface after the irradiation. The depth of holes can be affected by changes of laser energy while the diameter of holes have no corresponding relation. Plus, OCT, as a valuable imaging technology, is capable of monitoring the clinical therapy procedure and assisting the calibration.

The Efficacy and Safety of Ablative Fractional Resurfacing Using a 2,940-Nm Er:YAG Laser for Traumatic Scars in the Early Posttraumatic Period

Directory of Open Access Journals (Sweden)

Sun Goo Kim

2012-05-01

Full Text Available Background Skin injuries, such as lacerations due to trauma, are relatively common, andpatients are very concerned about the resulting scars. Recently, the use of ablative and nonablativelasers based on the fractional approach has been used to treat scars. In this study,the authors demonstrated the efficacy and safety of ablative fractional resurfacing (AFRfor traumatic scars using a 2,940-nm erbium: yttrium-aluminum-garnet (Er:YAG laser fortraumatic scars after primary repair during the early posttraumatic period.Methods Twelve patients with fifteen scars were enrolled. All had a history of faciallaceration and primary repair by suturing on the day of trauma. Laser therapy was initiatedat least 4 weeks after the primary repair. Each patient was treated four times at 1-monthintervals with a fractional ablative 2,940-nm Er:YAG laser using the same parameters. Posttreatmentevaluations were performed 1 month after the fourth treatment session.Results All 12 patients completed the study. After ablative fractional laser treatment, alltreated portions of the scars showed improvements, as demonstrated by the VancouverScar Scale and the overall cosmetic scale as evaluated by 10 independent physicians, 10independent non-physicians, and the patients themselves.Conclusions This study shows that ablative fractional Er:YAG laser treatment of scars reducesscars fairly according to both objective results and patient satisfaction rates. The authorssuggest that early scar treatment using AFR can be one adjuvant scar management methodfor improving the quality of life of patients with traumatic scars.

The effect of microablative fractional CO2 laser on vaginal flora of postmenopausal women.

Science.gov (United States)

Athanasiou, S; Pitsouni, E; Antonopoulou, S; Zacharakis, D; Salvatore, S; Falagas, M E; Grigoriadis, T

2016-10-01

To assess the effect of microablative fractional CO2 laser (MFCO2-Laser) therapy on the vaginal microenvironment of postmenopausal women. Three laser therapies at monthly intervals were applied in postmenopausal women with moderate to severe symptoms of genitourinary syndrome of menopause, pH of vaginal fluid >4.5 and superficial epithelial cells on vaginal smear Vaginal fluid pH values, fresh wet mount microscopy, Gram stain and aerobic and anaerobic cultures were evaluated at baseline and 1 month after each subsequent therapy. Nugent score and Hay-Ison criteria were used to evaluate vaginal flora. Fifty-three women (mean age 57.2 ± 5.4 years) participated and completed this study. MFCO2-Laser therapy increased Lactobacillus (p vaginal pH from a mean of 5.5 ± 0.8 (initial value) to 4.7 ± 0.5 (p aerobic vaginitis or candidiasis did not appear in any participant. MFCO2-Laser therapy is a promising treatment for improving the vaginal health of postmenopausal women by helping repopulate the vagina with normally existing Lactobacillus species and reconstituting the normal flora to premenopausal status.

Effects of non-ablative fractional erbium glass laser treatment on gene regulation in human three-dimensional skin models.

Science.gov (United States)

Amann, Philipp M; Marquardt, Yvonne; Steiner, Timm; Hölzle, Frank; Skazik-Voogt, Claudia; Heise, Ruth; Baron, Jens M

2016-04-01

Clinical experiences with non-ablative fractional erbium glass laser therapy have demonstrated promising results for dermal remodelling and for the indications of striae, surgical scars and acne scars. So far, molecular effects on human skin following treatment with these laser systems have not been elucidated. Our aim was to investigate laser-induced effects on skin morphology and to analyse molecular effects on gene regulation. Therefore, human three-dimensional (3D) organotypic skin models were irradiated with non-ablative fractional erbium glass laser systems enabling qRT-PCR, microarray and histological studies at same and different time points. A decreased mRNA expression of matrix metalloproteinases (MMPs) 3 and 9 was observed 3 days after treatment. MMP3 also remained downregulated on protein level, whereas the expression of other MMPs like MMP9 was recovered or even upregulated 5 days after irradiation. Inflammatory gene regulatory responses measured by the expression of chemokine (C-X-C motif) ligands (CXCL1, 2, 5, 6) and interleukin expression (IL8) were predominantly reduced. Epidermal differentiation markers such as loricrin, filaggrin-1 and filaggrin-2 were upregulated by both tested laser optics, indicating a potential epidermal involvement. These effects were also shown on protein level in the immunofluorescence analysis. This novel standardised laser-treated human 3D skin model proves useful for monitoring time-dependent ex vivo effects of various laser systems on gene expression and human skin morphology. Our study reveals erbium glass laser-induced regulations of MMP and interleukin expression. We speculate that these alterations on gene expression level could play a role for dermal remodelling, anti-inflammatory effects and increased epidermal differentiation. Our finding may have implications for further understanding of the molecular mechanism of erbium glass laser-induced effects on human skin.

Fractional ablative erbium YAG laser: histological characterization of relationships between laser settings and micropore dimensions.

Science.gov (United States)

Taudorf, Elisabeth H; Haak, Christina S; Erlendsson, Andrés M; Philipsen, Peter A; Anderson, R Rox; Paasch, Uwe; Haedersdal, Merete

2014-04-01

Treatment of a variety of skin disorders with ablative fractional lasers (AFXL) is driving the development of portable AFXLs. This study measures micropore dimensions produced by a small 2,940 nm AFXL using a variety of stacked pulses, and determines a model correlating laser parameters with tissue effects. Ex vivo pig skin was exposed to a miniaturized 2,940 nm AFXL, spot size 225 µm, density 5%, power levels 1.15-2.22 W, pulse durations 50-225 microseconds, pulse repetition rates 100-500 Hz, and 2, 20, or 50 stacked pulses, resulting in pulse energies of 2.3-12.8 mJ/microbeam and total energy levels of 4.6-640 mJ/microchannel. Histological endpoints were ablation depth (AD), coagulation zone (CZ) and ablation width (AW). Data were logarithmically transformed if required prior to linear regression analyses. Results for histological endpoints were combined in a mathematical model. In 138 sections from 91 biopsies, AD ranged from 16 to a maximum of 1,348 µm and increased linearly with the logarithm of total energy delivered by stacked pulses, but also depended on variations in power, pulse duration, pulse repetition rate, and pulse energy (r(2)  = 0.54-0.85, P micropores of specific ADs with an associated range of CZs and AWs, for example, 300 µm ADs were associated with CZs from 27 to 73 µm and AWs from 190 to 347 µm. Pulse stacking with a small, low power 2,940 nm AFXL created reproducible shallow to deep micropores, and influenced micropore configuration. Mathematical modeling established relations between laser settings and micropore dimensions, which assists in choosing laser settings for desired tissue effects. © 2014 Wiley Periodicals, Inc.

Laser beam pointing and stabilization by fractional-order PID control: Tuning rule and experiments

KAUST Repository

Al-Alwan, Asem Ibrahim Alwan; Guo, Xingang; Ndoye, Ibrahima; Laleg-Kirati, Taous-Meriem

2017-01-01

This paper studies the problem of high-precision positioning of laser beams by using a robust Fractional-Order Proportional-Integral-Derivative (FOPID) controller. The control problem addressed in laser beams aims to maintain the position of the laser beam on a Position Sensing Device (PSD) despite the effects of noise and active disturbances. The FOPID controller is well known for its simplicity with better tuning flexibility along with robustness to noise and output disturbance rejections. Thus, a control strategy based on FOPID to achieve the control objectives has been proposed. The FOPID gains and differentiation orders are optimally tuned in order to fulfill the robustness design specifications by solving a nonlinear optimization problem. A comparison to the conventional Proportional-Integral-Derivative (PID) and robust PID is also provided from simulation and experiment set-up. Due to sensor noise, practical PID controllers that filter the position signal before taking the derivative have been also proposed. Experimental results show that the requirements are totally met for the laser beam platform to be stabilized.

Laser beam pointing and stabilization by fractional-order PID control: Tuning rule and experiments

KAUST Repository

Al-Alwan, Asem Ibrahim Alwan

2017-10-24

This paper studies the problem of high-precision positioning of laser beams by using a robust Fractional-Order Proportional-Integral-Derivative (FOPID) controller. The control problem addressed in laser beams aims to maintain the position of the laser beam on a Position Sensing Device (PSD) despite the effects of noise and active disturbances. The FOPID controller is well known for its simplicity with better tuning flexibility along with robustness to noise and output disturbance rejections. Thus, a control strategy based on FOPID to achieve the control objectives has been proposed. The FOPID gains and differentiation orders are optimally tuned in order to fulfill the robustness design specifications by solving a nonlinear optimization problem. A comparison to the conventional Proportional-Integral-Derivative (PID) and robust PID is also provided from simulation and experiment set-up. Due to sensor noise, practical PID controllers that filter the position signal before taking the derivative have been also proposed. Experimental results show that the requirements are totally met for the laser beam platform to be stabilized.

Feedback-stabilized fractional fringe laser interferometer for plasma density measurements

International Nuclear Information System (INIS)

Schneider, J.; Robertson, S.

1979-01-01

A feedback stabilization technique is described for a fractional fringe interferometer measuring plasma electron densities. Using this technique, a CO 2 laser Michelson interferometer with a pyroelectric detector exhibited a sensitivity of 3.4 x 10 -4 fringe on a 1-ms time scale and, due to acoustic pickup, 1.8 x 10 -2 fringe on a 10-ms time scale. The rise time is 45 μs. Stabilization against slow drifts in mirror distances is achieved by an electromechanically translated mirror driven by a servo system having a 0.2-s response time. A mechanical chopper in one of the two beam paths generates the signal which drives the servo system

Fractional laser therapy – the next step in alleviating the symptoms of skin aging (own observations

Directory of Open Access Journals (Sweden)

Adam Halbina

2014-05-01

Full Text Available Skin aging is a natural process of the skin, which accelerates in menopause and is additionally intensified by accumulating effects of repeated exposure to solar UV radiation and other external factors. Anti-aging skin treatment and constant improvement of its methods have become an important area of current research. The need to apply effective skin anti-aging methods that minimize traumatization resulted in the development of fractional laser technology delivering a laser beam to microscopic column skin zones in order to achieve skin photo-remodeling.

Efficacy of autologous platelet-rich plasma combined with fractional ablative carbon dioxide resurfacing laser in treatment of facial atrophic acne scars: A split-face randomized clinical trial.

Science.gov (United States)

Faghihi, Gita; Keyvan, Shima; Asilian, Ali; Nouraei, Saeid; Behfar, Shadi; Nilforoushzadeh, Mohamad Ali

2016-01-01

Autologous platelet-rich plasma has recently attracted significant attention throughout the medical field for its wound-healing ability. This study was conducted to investigate the potential of platelet-rich plasma combined with fractional laser therapy in the treatment of acne scarring. Sixteen patients (12 women and 4 men) who underwent split-face therapy were analyzed in this study. They received ablative fractional carbon dioxide laser combined with intradermal platelet-rich plasma treatment on one half of their face and ablative fractional carbon dioxide laser with intradermal normal saline on the other half. The injections were administered immediately after laser therapy. The treatment sessions were repeated after an interval of one month. The clinical response was assessed based on patient satisfaction and the objective evaluation of serial photographs by two blinded dermatologists at baseline, 1 month after the first treatment session and 4 months after the second. The adverse effects including erythema and edema were scored by participants on days 0, 2, 4, 6, 8, 15 and 30 after each session. Overall clinical improvement of acne scars was higher on the platelet-rich plasma-fractional carbon dioxide laser treated side but the difference was not statistically significant either 1 month after the first treatment session (P = 0.15) or 4 months after the second (P = 0.23). In addition, adverse effects (erythema and edema) on the platelet-rich plasma-fractional carbon dioxide laser-treated side were more severe and of longer duration. Small sample size, absence of all skin phototypes within the study group and lack of objective methods for the evaluation of response to treatment and adverse effects were the limitations. This study demonstrated that adding platelet-rich plasma to fractional carbon dioxide laser treatment did not produce any statistically significant synergistic effects and also resulted in more severe side effects and longer downtime.

Fractional CO2 laser treatment for vulvovaginal atrophy symptoms and vaginal rejuvenation in perimenopausal women

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Arroyo C

2017-08-01

Full Text Available César Arroyo HM Montepríncipe University Hospital Laser Unit, Madrid, Spain Background: This study investigated a novel fractional carbon dioxide (CO2 laser for treatment of symptoms associated with vulvovaginal atrophy (VVA in perimenopausal women.Methods: The study included 21 perimenopausal women (mean age 45±7 years treated three times by CO2 laser resurfacing and coagulation of the vaginal canal tissue and mucosal tissue of the introitus. Vaginal health index (VHI scores were computed by the investigator at baseline and follow-ups. Subjects reported on sexual function, satisfaction, and improvement with treatment. A visual analog scale was used to measure discomfort with treatment.Results: Vaginal health and subject assessment of vaginal symptoms improved with successive treatments. At 12 weeks following the third treatment, 82% of the patients showed a statistically significant improvement in VHI (P<0.05. Additionally, 81% of subjects reported improvement in sexual gratification, 94% reported improvement in vaginal rejuvenation, and 100% reported satisfaction with treatment. VHI improvement remained significant at 6–8 months after treatments (P<0.01. Most patients (97% reported no to mild discomfort with treatment. Responses were mild and transient following treatment, with itching being the most commonly reported (20% side effect.Conclusion: In this study, fractional CO2 laser treatment was associated with improvement of vaginal health and amelioration of symptoms of VVA, resulting in improved sexual function in perimenopausal women. Treatment time was quick, and there was minimal discomfort associated with treatment. Investigation of clinical outcome in a larger study population is warranted. Keywords: genitourinary syndrome of menopause, vaginal rejuvenation, stress urinary incontinence, collagen remodeling, sexual dysfunction, vulvovaginal atrophy

Therapeutic Effect of Fractionated Ultra-Pulse CO2 Laser and Fractionated Er∶YAG Laser on Enlarged Facial Pores: an Observation and Comparison%点阵式超脉冲CO2激光和点阵式Er∶YAG激光治疗面部毛孔粗大的疗效比较

Institute of Scientific and Technical Information of China (English)

张元文; 靳贺; 罗世兰; 陈永新; 王娅; 潘文东

2017-01-01

Objective To observe and compare the clinic efficacy and operation safety of fractionated ultra-pulse CO2 laser and fractionated Er ∶ YAG laser in the treatment of enlarged facial pores.Methods Totally 60 patients with enlarged facial pores were divided into two groups randomly:30 of them were treated with fractionated ultrapulse CO2 laser and the rest with fractionated Er ∶ YAG laser.During the follow-up conducted 3 months after the treatment,the clinical improvement was evaluated with a photographic scale for grading the widening of pores,and the adverse reaction was assessed.Results After the treatment,the improvement in the appearance of facial pores was distinctive (P ＜ 0.05) in each group.The difference between the fractionated ultra-pulse CO2 laser group and fractionated Er∶ YAG laser group in clinic efficacy was statistically significant (P ＜ 0.05).The patients'satisfaction rate was 83.3％ for the fractionated ultrapulse CO2 laser group and 90.0％ for the fractionated Er∶YAG laser group.The adverse events were limited to transient pain,erythema,edema and crust desquamates.No permanent hyperpigmentation,hypopigmentation or scar was observed.Conclusions Both fractionated ultra-pulse CO2 laser and fractionated Er∶YAG laser may shrink enlarged facial pores effectively with minimal side effects.%目的 比较点阵式超脉冲CO2激光与点阵式Er∶YAG激光治疗面部毛孔粗大的疗效及安全性.方法 面部毛孔粗大患者60例,随机分为两组,每组30例,分别采用点阵式CO2激光与点阵式Er∶ YAG激光治疗.疗程结束后随访3个月,应用面部毛孔标准照片评价法进行临床疗效评估并比较两组疗效.结果 点阵CO2激光组治疗前与治疗后3个月患者面部毛孔标准照片评分分别为(4.97 ±0.77)和(2.00 ±0.95),点阵Er∶YAG激光组分别为(5.03 ±0.77)和(2.40±0.82),组内比较治疗前后差异具有统计学意义(P＜0.05).组间比较点阵CO2�

Topically applied methotrexate is rapidly delivered into skin by fractional laser ablation

DEFF Research Database (Denmark)

Taudorf, Elisabeth Hjardem; Lerche, Catharina; Vissing, Anne-Cathrine

2015-01-01

Objectives: Methotrexate (MTX) is a chemotherapeutic and anti-inflammatory drug that may cause systemic adverse effects. This study investigated kinetics and biodistribution of MTX delivered topically by ablative fractional laser (AFXL). Methods: In vitro passive diffusion of 10 mg/ml MTX (1 w...... sections, donor and receiver compartments. Fluorescence microscopy of UVC-activated MTX-fluorescence and desorption electro-spray ionization mass spectrometry imaging (DESI-MSI) evaluated MTX biodistribution. Results: AFXL-processed skin facilitated rapid MTX delivery through cone-shaped microchannels.......30 mg/cm3, p = 0.002). Transdermal permeation was

Histological examination of the oral mucosa after fractional diode laser irradiation with different power and pulse duration

Science.gov (United States)

Belikov, Andrey V.; Ermolaeva, Ludmila A.; Korzhevsky, Dmitriy E.; Sergeeva, Elena S.; Semyashkina, Yulia V.; Antropova, Maria M.; Fedotov, Denis Y.; Zaitseva, Maria A.; Kashina, Tatiana V.

2018-04-01

Optical and histological methods were used to examination of influence the power and pulse duration of 980-nm diode laser to the dimensions and morphology of tissue around fractional micro injuries created by the radiation of that laser in the oral mucosa of rats in vivo. The power of laser radiation (P) varied in the range of 1÷21 W, and its pulse duration (tp) - in the range 50÷500 ms. Histological examination showed that in the mucosa of the oral cavity after the laser fractional irradiation, there following effects are found: a tissue defect, a transudate in the lumen of ablative micro injury, stretching and compacting effect of the nuclei of the basal epithelium, the disappearance of granules of the keratohialin, destroying the structure of the connective tissue, erythrocyte stasis in the vessels, the disappearance of transverse striation in the muscle fibers in muscle layer. It has been found that ablative micro injury begins to form up at P = 5 W, tp = 100 ms and affects only the epithelial layer of the mucosa. At P = 7 W, tp = 120 ms, the ratio of width to depth of ablative micro injury is 1 : 1, and at P = 10 W, tp = 100 ms, an ablative micro column with ratio of 1 : 1.5 is formed in the epithelial and submucosal layers of the mucosa. The laser effect with P = 15 W, tp = 200 ms leads to lengthening of the ablation micro-column to 1 : 2, with the bottom of the ablative micro column reaching the muscular layer. With a further growth of laser power or pulse duration, the width of the micro injury increases, and the growth of the micro injury depth is slowed down so that the micro column buildup is ceased.

A Comparison between the Effects of Glucantime, Topical Trichloroacetic Acid 50% plus Glucantime, and Fractional Carbon Dioxide Laser plus Glucantime on Cutaneous Leishmaniasis Lesions

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Fariba Jaffary

2016-01-01

Full Text Available Background. Cutaneous leishmaniasis is an endemic disease in Iran. Pentavalent antimonial drugs have been the first line of therapy in cutaneous leishmaniasis for many years. However, the cure rate of these agents is still not favorable. This study was carried out to compare the efficacies of intralesional glucantime with topical trichloroacetic acid 50% (TCA 50% + glucantime and fractional carbon dioxide laser + glucantime in the treatment of cutaneous leishmaniasis. Methods. A total of 90 patients were randomly divided into three groups of 30 to be treated with intralesional injection of glucantime, a combination of topical TCA 50% and glucantime, or a combination of fractional laser and glucantime. The overall clinical improvement and changes in sizes of lesions and scars were assessed and compared among three groups. Results. The mean duration of treatment was 6.1±2.1 weeks in all patients (range: 2–12 weeks and 6.8±1.7, 5.2±1.0, and 6.3±3.0 weeks in glucantime, topical TCA plus glucantime, and fractional laser plus glucantime groups, respectively (P=0.011. Complete improvement was observed in 10 (38.5%, 27 (90%, and 20 (87% patients of glucantime, glucantime + TCA, and glucantime + laser groups, respectively (P<0.001. Conclusion. Compared to glucantime alone, the combination of intralesional glucantime and TCA 50% or fractional CO2 laser had significantly higher and faster cure rate in patients with cutaneous leishmaniasis.

Biophysical evaluation of fractional laser skin resurfacing with an Er:YSGG laser device in Japanese skin.

Science.gov (United States)

Kimura, Utako; Kinoshita, Ayako; Osawa, Aki; Negi, Osamu; Haruna, Kunitaka; Mizuno, Yuki; Suga, Yasushi

2012-05-01

Ablative fractional laser skin resurfacing (FLSR) has recently been used for the amelioration of acne scars, and previous studies have shown clinical effectiveness. Despite its extensive use, few studies have focused on the associated changes in biophysical properties of the epidermis. Herein, we evaluate transepidermal water loss, sebum levels, skin hydration, and skin elasticity, following FLSR treatments with an Er:YSGG laser device (Pearl FractionalTM, Cutera Inc., Brisbane, CA), employing non-invasive measurements. Five Japanese patients with facial acne scars underwent one FLSR session. Some acne scars appeared to become less obvious as a consequence of the treatment. All patients were aware of a feeling of skin tightness in treated areas. Objective measurements on the lower lateral angle of the eye and on the inner cheeks were evaluated at baseline and at 3 days, 1 week, and 4 weeks after FLSR. Transepidermal water loss showed a significant two-fold (100%) increase at day 3, but had returned to almost the baseline level at week 4 in both areas. Sebum secretion showed a 50% increase at day 3, but had returned to the baseline level after day 7. Skin hydration showed a significant decrease at day 3, but had returned to the baseline level by day 7, and showed significant improvement at the end of the study. Skin elasticity (R2) was still at baseline on day 3, but showed some improvement--an increase of at least 30%--at the end of the study. Based on our findings, we believe that FLSR should be performed no more than once a month to allow sufficient time for the damaged skin to recover its barrier function in most areas of the face.

Testing the Application of Terrestrial Laser Scanning to Measure Forest Canopy Gap Fraction

Directory of Open Access Journals (Sweden)

F. Mark Danson

2013-06-01

Full Text Available Terrestrial laser scanners (TLS have the potential to revolutionise measurement of the three-dimensional structure of vegetation canopies for applications in ecology, hydrology and climate change. This potential has been the subject of recent research that has attempted to measure forest biophysical variables from TLS data, and make comparisons with two-dimensional data from hemispherical photography. This research presents a systematic comparison between forest canopy gap fraction estimates derived from TLS measurements and hemispherical photography. The TLS datasets used in the research were obtained between April 2008 and March 2009 at Delamere Forest, Cheshire, UK. The analysis of canopy gap fraction estimates derived from TLS data highlighted the repeatability and consistency of the measurements in comparison with those from coincident hemispherical photographs. The comparison also showed that estimates computed considering only the number of hits and misses registered in the TLS datasets were consistently lower than those estimated from hemispherical photographs. To examine this difference, the potential information available in the intensity values recorded by TLS was investigated and a new method developed to estimate canopy gap fraction proposed. The new approach produced gap fractions closer to those estimated from hemispherical photography, but the research also highlighted the limitations of single return TLS data for this application.

Treatment of cosmetic tattoos with nonablative fractional laser in an animal model: a novel method with histopathologic evidence.

Science.gov (United States)

Wang, Chia-Chen; Huang, Chuen-Lin; Lee, Shao-Chen; Sue, Yuh-Mou; Leu, Fur-Jiang

2013-02-01

Cosmetic tattoos are difficult to treat using Q-switched lasers. We introduce a novel method for the treatment of cosmetic tattoos using a nonablative fractional laser and investigate the underlying pathophysiological mechanisms in an animal model. Ten rats were tattooed on their backs with white and flesh-colored pigments. One-half of each tattoo was treated with a 1,550-nm, erbium:glass fractional laser system with energy settings of 17 mJ and 169 MTZ/cm(2)  × 2 passes for five sessions at 1-month intervals. The untreated half of each tattoo served as the control. An independent physician reviewed the photographs and scored the clinical response. Serial skin samples were obtained at baseline and at various times after laser treatment. These tissue sections were stained with hematoxylin and eosin, and immunostained for types I, III, and IV collagen; laminin; fibronectin; and α-smooth muscle actin. White tattoos showed excellent responses in two rats and good responses in eight rats, whereas flesh-colored tattoos showed excellent responses in four rats and good responses in six rats (P = 0.001 in both cases compared with baseline). Both tattoos exhibited a similar clearance rate (P > 0.05) and histological reactions. Microscopic epidermal necrotic debris (MEND) containing tattoo pigments and collagen fibrils appeared on day 1, increased on day 2, and was exfoliated after 5 days. The dermal-epidermal junction lost integrity 30 minutes after treatment, but recovered completely on day 3. The expression of fibronectin and collagen-III, which play key roles in wound healing, increased around the microscopic treatment zone on days 1-5 and 4-7, respectively. A few myofibroblasts appeared on days 4-7. Nonablative fractional lasers (NAFLs) successfully remove cosmetic tattoos by transepidermal elimination of tattoo pigments through the disrupted dermal-epidermal junction. This action is facilitated by the wound healing process. Copyright © 2013 Wiley

Early Regenerative Modifications of Human Postmenopausal Atrophic Vaginal Mucosa Following Fractional CO2 Laser Treatment

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Stefano Salvatore

2018-01-01

Full Text Available BACKGROUND: Postmenopausal women experience undesired symptoms that adversely affect their quality of life. In the recent years, a specific 12 - week fractional CO2 laser treatment has been introduced, with highly significant relief of symptoms. AIM: The aim of this paper is the identification of the early modifications of structural components of atrophic vaginal mucosa induced by laser irradiation, which is responsible for the restorative processes. MATERIAL AND METHODS: We investigated by microscopical, ultrastructural and biochemical methods the modifications of the structural components of postmenopausal atrophic vaginal mucosa tissues after 1 hour following a single fractional laser CO2 application. RESULTS: In one hour, the mucosal epithelium thickens, with the maturation of epithelial cells and desquamation at the epithelial surface. In the connective tissue, new papillae indenting the epithelium with newly formed vessels penetrating them, new thin fibrils of collagen III are also formed in a renewed turnover of components due to the increase of metalloproteinase - 2. Specific features of fibroblasts support stimulation of their activity responsible of the renewal of the extracellular matrix, with an increase of mechanical support as connective tissue and stimulation of growth and maturation to epithelium thanks to new vessels and related factors delivered. CONCLUSION: We found the activation of regenerative mechanisms expressed both in the connective tissue - with the formation of new vessels, new papillae, and new collagen - and in the epithelium with the associated thickening and desquamation of cells at the mucosal surface.

Clinical and Histological Evaluations of Enlarged Facial Skin Pores After Low Energy Level Treatments With Fractional Carbon Dioxide Laser in Korean Patients.

Science.gov (United States)

Kwon, Hyuck Hoon; Choi, Sun Chul; Lee, Won-Yong; Jung, Jae Yoon; Park, Gyeong-Hun

2018-03-01

Enlarged facial pores can be an early manifestation of skin aging and they are a common aesthetic concern for Asians. However, studies of improving the appearance of enlarged pores have been limited. The authors aimed to study the application of CO2 fractional laser treatment in patients with enlarged facial pores. A total of 32 patients with dilated facial pores completed 3 consecutive sessions of low energy level treatments with a fractional CO2 laser at 4-week intervals. Image analysis was performed to calculate the number of enlarged pores before each treatment session and 12 weeks after the final treatment. After application of laser treatments, there was a significant decrease in the number of enlarged pores. The mean number of enlarged pores was decreased by 28.8% after the second session and by 54.5% at post-treatment evaluation. Post-treatment side effects were mild and transitory. Histological and immunohistochemical analyses demonstrated clear increases in the number of collagen fibers and the expression of transforming growth factor-β1. The short-term results showed that treatment with low energy level CO2 fractional laser therapy could be a safe and effective option for patients with Fitzpatrick skin Types III and IV who are concerned with enlarged pores.

Fractional ablative carbon dioxide laser followed by topical sodium stibogluconate application: A treatment option for pediatric cutaneous leishmaniasis.

Science.gov (United States)

Hilerowicz, Yuval; Koren, Amir; Mashiah, Jacob; Katz, Oren; Sprecher, Eli; Artzi, Ofir

2018-05-01

Leishmaniasis is a protozoan zoonotic parasitic infection with cutaneous, mucocutaneous, and visceral manifestations. Israel is endemic for cutaneous leishmaniasis, which is a self-limited disease but is associated with scarring, which is often a source of psychological and social burden for patients. Scars can be especially devastating for children and teenagers. A wide range of physical and medical approaches is used to treat cutaneous leishmaniasis, among which intralesional injections of sodium stibogluconate rank among the most frequently used. Unfortunately, despite being effective, this therapeutic modality can be very painful. Fractional ablative laser creates a controlled mesh-like pattern of tissue ablation in the skin that promotes dermal remodeling and collagen production while at the same time facilitating enhanced delivery of topically applied medications. Patients were treated with fractional ablative carbon dioxide laser followed by immediate topical application of sodium stibogluconate. All children were diagnosed with cutaneous leishmaniasis prior to treatment initiation.. Ten children were treated. One leishmania tropica-positive girl failed to respond. The other nine patients achieved clinical cure and demonstrated good to excellent final cosmesis. Self-rated patient satisfaction and tolerance were high No adverse effects were observed or reported during treatment. Fractional ablative carbon dioxide laser followed by topical sodium stibogluconate application appears to be a safe and promising treatment for cutaneous leishmaniasis infection in children. Future controlled studies are required to validate these findings and compare this technique with traditional approaches. © 2018 Wiley Periodicals, Inc.

Endovenous and perivenous 808-nm laser treatment of lower limb collateral, reticular and telangiectasiac veins.

Science.gov (United States)

Bugiantella, Walter; Bovani, Bruno; Zini, Francesco

2017-02-01

Visible leg veins are not only a mere aesthetic problem, but may also be manifestation of altered microcirculation and superficial venous incompetency. Sclerotherapy is the first-line treatment for leg veins veins: the greater, the harder photothermolysis is, so that higher powers may lead to aesthetic complications. We report our experience in the treatment of small collateral (reticular and telangiectasiac veins with endovenous and perivenous 808-nm laser. Overall, 325 treatments were performed on 113 patients. The endovenous and perivenous treatment proved to be a safe, quick, well-tolerated and effective procedure. It ensured an optimal closure of the target veins right from the first treatment in most patients. Sometimes, a second treatment of the same vein was needed. The endovenous and perivenous 808-nm laser photothermal sclerosis ensures a quick coagulation-fibrosis of the veins of the lower limbs, thus allowing rapid healing and good aesthetic results (stable in 95% of patients after an average follow-up of 18 months). It may be an effective alternative to sclerotherapy.

Efficacy of autologous platelet-rich plasma combined with fractional ablative carbon dioxide resurfacing laser in treatment of facial atrophic acne scars: A split-face randomized clinical trial

Directory of Open Access Journals (Sweden)

Gita Faghihi

2016-01-01

Full Text Available Background: Autologous platelet-rich plasma has recently attracted significant attention throughout the medical field for its wound-healing ability. Aims: This study was conducted to investigate the potential of platelet-rich plasma combined with fractional laser therapy in the treatment of acne scarring. Methods: Sixteen patients (12 women and 4 men who underwent split-face therapy were analyzed in this study. They received ablative fractional carbon dioxide laser combined with intradermal platelet-rich plasma treatment on one half of their face and ablative fractional carbon dioxide laser with intradermal normal saline on the other half. The injections were administered immediately after laser therapy. The treatment sessions were repeated after an interval of one month. The clinical response was assessed based on patient satisfaction and the objective evaluation of serial photographs by two blinded dermatologists at baseline, 1 month after the first treatment session and 4 months after the second. The adverse effects including erythema and edema were scored by participants on days 0, 2, 4, 6, 8, 15 and 30 after each session. Results: Overall clinical improvement of acne scars was higher on the platelet-rich plasma-fractional carbon dioxide laser treated side but the difference was not statistically significant either 1 month after the first treatment session (P = 0.15 or 4 months after the second (P = 0.23. In addition, adverse effects (erythema and edema on the platelet-rich plasma-fractional carbon dioxide laser-treated side were more severe and of longer duration. Limitations: Small sample size, absence of all skin phototypes within the study group and lack of objective methods for the evaluation of response to treatment and adverse effects were the limitations. Conclusion: This study demonstrated that adding platelet-rich plasma to fractional carbon dioxide laser treatment did not produce any statistically significant synergistic effects

Picosecond Laser Treatment for Tattoos and Benign Cutaneous Pigmented Lesions (Secondary publication).

Science.gov (United States)

Kasai, Kenichiro

2017-12-31

The selective removal of tattoos and benign cutaneous pigmented lesions with laser energy evolved rapidly with the development of the nanosecond-domain Q-switched laser (ns-laser). Recently, however, a series of picosecond-domain lasers (ps-lasers) with pulsewidths less than 1 ns has become commercially available, enabling more efficient and faster removal of pigmented lesions in the field of dermatologic laser surgery. The efficacy of the ns-laser depended on the theory of selective photothermolysis, whereby an extremely short pulse width was delivered less than the thermal relaxation time (TRT) of a target. At sub-ns pulsewidths, i.e. in the ps-domain, this efficacy is dramatically extended through defeating the stress relaxation time (SRT) of a target allowing for even more effective pigment destruction with even less damage to the surrounding normal tissue. This will be discussed in detail. The ps-laser has been reported as achieving tattoo removal in fewer sessions than the ns-laser, with less in the way of unwanted side effects. Tattoos recalcitrant to ns-laser treatment have responded well to the ps-laser, and although true 'color blindness' is not yet completely achieved with the ps-domain pulses currently available, multicolored tattoos have also responded very favorably. The ability to limit damage precisely to the pigment target gives greater efficacy in treatment of epidermal lesions with less induction of post-inflammatory hyperpigmentation in the PIH-susceptible Asian skin, and dermal melanocytosis also respond very well to ps-laser treatment. Illustrative clinical examples from the author's experience are given. Current ps-lasers could be a revolutionary advance for laser tattoo removal but may be less effective for some specific aesthetic indications such as melasma and other cosmetic procedures. Manufacturers must make an effort to reduce the current comparatively long ps-domain pulsewidths to deliver a 'true' ps-domain laser, with more basic

Fractional carbon dioxide laser resurfacing of rhytides and photoaged skin--a prospective clinical study on patient expectation and satisfaction.

Science.gov (United States)

Kohl, Elisabeth; Meierhöfer, Julia; Koller, Michael; Zeman, Florian; Groesser, Leopold; Karrer, Sigrid; Hohenleutner, Ulrich; Landthaler, Michael; Hohenleutner, Silvia

2015-02-01

Fractional CO2 -laser resurfacing is increasingly used for treating rhytides and photoaged skin because of its favorable benefit-risk ratio. A key outcome measure and treatment goal in aesthetic laser therapy is patient satisfaction. However, few data are available on patient-reported outcomes after fractional ablative skin-resurfacing. To compare patient expectations before and patient satisfaction after three fractional CO2 -laser treatments and to correlate objectively measured wrinkle reduction with patient satisfaction after treatment. We investigated patient expectation and satisfaction using a 14-item questionnaire in 24 female patients. We assessed the skin-related quality of life and patient satisfaction with skin appearance. We profilometrically measured wrinkle size in four facial areas before and three months after treatment and investigated correlations between wrinkle reduction and patient satisfaction. The high patient expectations before treatment (ceiling effect) were actually slightly exceeded. The average score of 14 items delineating patient satisfaction with laser treatment was higher (4.64 ± 0.82; n = 24) than the respective expectations before treatment (4.43 ± 0.88; n = 24). Skin-related quality of life and patient satisfaction with skin appearance had significantly improved after the last treatment. Patients dissatisfied with their skin appearance before treatment (mean 2.1 ± 1.5; evaluated on a scale ranging from 0-6) were satisfied (mean 5.1 ± 1.2) (P skin appearance at the follow-up. Patient satisfaction with skin appearance was not correlated to the profilometrically measured reduction of wrinkle size of any facial area. Our results show high patient satisfaction with ablative fractional skin resurfacing, also regarding improved self-esteem and self-satisfaction despite high pre-treatment expectations. Skin-specific quality of life had significantly improved. Thus, this treatment modality can be recommended

Lower energy and pulse stacking. A safer alternative for skin tightening using fractional CO2 laser.

Science.gov (United States)

Motta, Marcos Matias; Stelini, Rafael Fantelli; Calderoni, Davi Reis; Gilioli, Rovilson; Kharmandayan, Paulo

2016-01-01

To evaluate the effect of different energies and stacking in skin shrinkage. Three decreasing settings of a fractional CO2 laser were applied to the abdomen of Twenty five Wistar rats divided into three groups. Group I (n=5) was histologically evaluated for microthermal zones dimensions. Groups II and III (n=10 each) were macroscopic evaluated with freeware ImageJ for area contraction immediately and after 30 and 60 days. No statistical significance was found within microthermal zone histological dimensions (Group I) in all settings studied. (Ablation depth: 76.90 to 97.18µm; Coagulation depth: 186.01 to 219.84 µm). In Group II, macroscopic evaluation showed that all settings cause significant immediate skin contraction. The highest setting cause significant more intense tightening effect initially, contracting skin area from 258.65 to 179.09 mm2. The same pattern was observed in Group III. At 30 and 60 days, the lowest setting significantly sustained contraction. Lower fractional CO2 laser energies associated to pulse stacking could cause consistent and long lasting tissue contraction in rats.

Enhancing hair growth in male androgenetic alopecia by a combination of fractional CO2 laser therapy and hair growth factors.

Science.gov (United States)

Huang, Yue; Zhuo, Fenglin; Li, Linfeng

2017-11-01

Laser therapy and growth factors have been used as alternative treatments for male androgenetic alopecia (MAA). The aim of this study is to determine the efficacy and safety of hair growth factors alone or combined with ablative carbon dioxide (CO 2 ) fractional laser therapy in MAA. Twenty-eight men were enrolled in this randomized half-split study based on a left-head to right-head pattern. Fractional CO 2 laser treatment was unilaterally performed; hair growth factors were bilaterally applied. Six sessions with 2-week intervals were performed. Global photographs and dermoscopy assessments were performed at the baseline and 4 months after first treatment. Global photographs underwent blinded review by three independent dermatologists. Scanning electron microscopy was used to compare changes in hair-follicle phase and hair-shaft diameter. Twenty-seven participants completed the 4-month treatment schedule. One patient was lost. Mean hair density increased from 114 ± 27 to 143 ± 25/cm 2 (P laser combined with hair growth factors may serve as an alternative treatment for MAA in individuals unwilling/unable to undergo medical or surgical treatment.

The long-term effect of 1550 nm erbium:glass fractional laser in acne vulgaris.

Science.gov (United States)

Liu, Yale; Zeng, Weihui; Hu, Die; Jha, Smita; Ge, Qin; Geng, Songmei; Xiao, Shengxiang; Hu, Guanglei; Wang, Xiaoxiao

2016-04-01

We evaluated the short-term and long-term effects of the 1550 nm erbium:glass (Er:glass) fractional laser in the treatment of facial acne vulgaris. Forty-five (9 male and 36 female) acne patients were treated 4 times at 4-week intervals with the following parameters: 169 spot density and 15-30 mJ/cm(2) fluence. There was no control group. The laser spots were adjustable (maximum overlap: 20%) according to the treatment area, and delivered in rows in order to cover all the face. Clinical photographs were taken. The IGA scores and lesion counts were performed for each treatment. Their current state was obtained by phone call follow-up to determine the long-term effect and photographs were offered by themselves or taken in hospital. After four treatments, all patients had an obvious reduction of lesion counts and IGA score and the peak lesion counts decreased to 67.7% after the initial four treatment sessions. For long-term effect, 8 patients lost follow-up, hence 37 patients were followed-up. 8 patients were 2-year follow up, 27 at the 1-year follow-up, and all patients at the half-year follow-up. The mean percent reduction was 72% at the half-year follow-up, 79 at the 1-year follow-up and 75% at the 2-year follow-up. Side effects and complications were limited to transient erythema and edema, and few patients suffered from transient acne flare-ups and sensitivity. All patients responded that their skin was less prone to oiliness. In conclusion, acne can be successfully treated by 1550 nm Er:glass fractional laser, with few side effects and prolonged acne clearing.

SPF-RR sequential photothermal fractional resurfacing and remodeling with the variable pulse Er:YAG laser and scanner-assisted Nd:YAG laser.

Science.gov (United States)

Marini, Leonardo

2009-12-01

Many different lasers, polychromatic high-intensity light sources (PCLs), and RF devices have claimed clinical efficacy in rejuvenating the skin. In this study, the sequential combination of two different laser wavelengths was evaluated to produce reliably significant clinical improvements optimizing treatment parameters. The left volar aspects of the forearms of four volunteers were treated with nine different parameter settings using a variable pulsewidth fractional Er:YAG 2940-nm laser with and without air cooling. The pain perception level was recorded on a 0-10 point scale (0=No pain; 10=Most severe pain). Three evaluations were made: during treatment, immediately after treatment, and 5 minutes after treatment. The same investigation was made on the right volar aspects of the same four volunteers using a short-pulse, random pattern, 3-mm spot, scanner-assisted Nd-YAG 1064-nm laser at 0.3 ms pulsewidth at seven different parameter settings. Clinical evaluations were made concerning erythema and edema 3 days after treatment, as well as pre-operative and 60 days postoperative skin texture plus color uniformity. Considering that the majority of cosmetic patients are willing to accept a relatively short and uneventful downtime (2-4 days according to a study we are presently conducting) and do prefer to limit their intra- and postoperative pain to a minimum, the best combination of clinical improvement matching these two important parameters were selected for our study. A treatment strategy combining two sequential passes of long-pulse Nd:YAG laser (Nd:YAG-LP) at 0.3 and 35 ms followed by two passes of long-pulse fractional Er:YAG laser (Er:YAG-FT) at 600 micros was designed to treat the facial regions of 10 volunteers affected by a combination of intrinsic (chrono-) and extrinsic (mostly photo-) aging. The pain perception level was recorded on a 0-10 scale (0=No pain; 10=Most severe pain). Three evaluations were made: during, immediately after, and 5 minutes after

Non-ablative 1550 nm fractional laser therapy not effective for erythema dyschromicum perstans and postinflammatory hyperpigmentation: a pilot study

NARCIS (Netherlands)

Kroon, Marije W.; Wind, Bas S.; Meesters, Arne A.; Wolkerstorfer, Albert; van der Veen, J. P. Wietze; Bos, Jan D.; van der Wal, Allard C.; Beek, Johan F.

2012-01-01

Background: Erythema dyschromicum perstans and postinflammatory hyperpigmentation (PIH) are characterized by papillary dermal pigmentation or pigment incontinence. To date, no standard treatment is available. Fractional laser therapy (FLT) was recently reported to improve different pigment

Improving the outcome of fractional CO2 laser resurfacing using a probiotic skin cream: Preliminary clinical evaluation.

Science.gov (United States)

Zoccali, Giovanni; Cinque, Benedetta; La Torre, Cristina; Lombardi, Francesca; Palumbo, Paola; Romano, Lucia; Mattei, Antonella; Orsini, Gino; Cifone, Maria Grazia; Giuliani, Maurizio

2016-11-01

As known, fractional CO 2 resurfacing treatments are more effective than non-ablative ones against aging signs, but post-operative redness and swelling prolong the overall downtime requiring up to steroid administration in order to reduce these local systems. In the last years, an increasing interest has been focused on the possible use of probiotics for treating inflammatory and allergic conditions suggesting that they can exert profound beneficial effects on skin homeostasis. In this work, the Authors report their experience on fractional CO 2 laser resurfacing and provide the results of a new post-operative topical treatment with an experimental cream containing probiotic-derived active principles potentially able to modulate the inflammatory reaction associated to laser-treatment. The cream containing DermaACB (CERABEST™) was administered post-operatively to 42 consecutive patients who were treated with fractional CO 2 laser. All patients adopted the cream twice a day for 2 weeks. Grades were given according to outcome scale. The efficacy of the cream containing DermaACB was evaluated comparing the rate of post-operative signs vanishing with a control group of 20 patients topically treated with an antibiotic cream and a hyaluronic acid based cream. Results registered with the experimental treatment were good in 22 patients, moderate in 17, and poor in 3 cases. Patients using the study cream took an average time of 14.3 days for erythema resolution and 9.3 days for swelling vanishing. The post-operative administration of the cream containing DermaACB induces a quicker reduction of post-operative erythema and swelling when compared to a standard treatment.

Mixture-fraction imaging at 1  kHz using femtosecond laser-induced fluorescence of krypton.

Science.gov (United States)

Richardson, Daniel R; Jiang, Naibo; Stauffer, Hans U; Kearney, Sean P; Roy, Sukesh; Gord, James R

2017-09-01

Femtosecond, two-photon-absorption laser-induced-fluorescence (TALIF) imaging measurements of krypton (Kr) are demonstrated to study mixing in gaseous flows. A measurement approach is presented in which observed Kr TALIF signals are 7 times stronger than the current state-of-the-art methodology. Fluorescence emission is compared for different gas pressures and excitation wavelengths, and the strongest fluorescence signals were observed when the excitation wavelength was tuned to 212.56 nm. Using this optimized excitation scheme, 1-kHz, single-laser-shot visualizations of unsteady flows and two-dimensional measurements of mixture fraction and scalar dissipation rate of a Kr-seeded jet are demonstrated.

Excellent Aesthetic and Functional Outcome After Fractionated Carbon Dioxide Laser Skin Graft Revision Surgery: Case Report and Review of Laser Skin Graft Revision Techniques.

Science.gov (United States)

Ho, Derek; Jagdeo, Jared

2015-11-01

Skin grafts are utilized in dermatology to reconstruct a defect secondary to surgery or trauma of the skin. Common indications for skin grafts include surgical removal of cutaneous malignancies, replacement of tissue after burns or lacerations, and hair transplantation in alopecia. Skin grafts may be cosmetically displeasing, functionally limiting, and significantly impact patient's quality-of-life. There is limited published data regarding skin graft revision to enhance aesthetics and function. Here, we present a case demonstrating excellent aesthetic and functional outcome after fractionated carbon dioxide (CO2) laser skin graft revision surgery and review of the medical literature on laser skin graft revision techniques.

Tunable diode laser absorption spectroscopy-based tomography system for on-line monitoring of two-dimensional distributions of temperature and H2O mole fraction

International Nuclear Information System (INIS)

Xu, Lijun; Liu, Chang; Jing, Wenyang; Cao, Zhang; Xue, Xin; Lin, Yuzhen

2016-01-01

To monitor two-dimensional (2D) distributions of temperature and H 2 O mole fraction, an on-line tomography system based on tunable diode laser absorption spectroscopy (TDLAS) was developed. To the best of the authors’ knowledge, this is the first report on a multi-view TDLAS-based system for simultaneous tomographic visualization of temperature and H 2 O mole fraction in real time. The system consists of two distributed feedback (DFB) laser diodes, a tomographic sensor, electronic circuits, and a computer. The central frequencies of the two DFB laser diodes are at 7444.36 cm −1 (1343.3 nm) and 7185.6 cm −1 (1391.67 nm), respectively. The tomographic sensor is used to generate fan-beam illumination from five views and to produce 60 ray measurements. The electronic circuits not only provide stable temperature and precise current controlling signals for the laser diodes but also can accurately sample the transmitted laser intensities and extract integrated absorbances in real time. Finally, the integrated absorbances are transferred to the computer, in which the 2D distributions of temperature and H 2 O mole fraction are reconstructed by using a modified Landweber algorithm. In the experiments, the TDLAS-based tomography system was validated by using asymmetric premixed flames with fixed and time-varying equivalent ratios, respectively. The results demonstrate that the system is able to reconstruct the profiles of the 2D distributions of temperature and H 2 O mole fraction of the flame and effectively capture the dynamics of the combustion process, which exhibits good potential for flame monitoring and on-line combustion diagnosis

Effects of early combinatorial treatment of autologous split-thickness skin grafts in red duroc pig model using pulsed dye laser and fractional CO2 laser.

Science.gov (United States)

Bailey, J Kevin; Blackstone, Britani N; DeBruler, Danielle M; Kim, Jayne Y; Baumann, Molly E; McFarland, Kevin L; Imeokparia, Folasade O; Supp, Dorothy M; Powell, Heather M

2018-01-01

The use of pulsed dye laser (PDL) and fractional CO 2 (FX CO 2 ) laser therapy to treat and/or prevent scarring following burn injury is becoming more widespread with a number of studies reporting reduction in scar erythema and pruritus following treatment with lasers. While the majority of studies report positive outcomes following PDL or FX CO 2 therapy, a number of studies have reported no benefit or worsening of the scar following treatment. The objective of this study was to directly compare the efficacy of PDL, FX CO 2 , and PDL + FX CO 2 laser therapy in reducing scarring post burn injury and autografting in a standardized animal model. Eight female red Duroc pigs (FRDP) received 4 standardized, 1 in. x 1 in. third degree burns that were excised and autografted. Wound sites were treated with PDL, FX CO 2 , or both at 4, 8, and 12 weeks post grafting. Grafts receiving no laser therapy served as controls. Scar appearance, morphology, size, and erythema were assessed and punch biopsies collected at weeks 4, 8, 12, and 16. At week 16, additional tissue was collected for biomechanical analyses and markers for inflammatory cytokines, extracellular matrix (ECM) proteins, re-epithelialization, pigmentation, and angiogenesis were quantified at all time points using qRT-PCR. Treatment with PDL, FX CO 2 , or PDL + FX CO 2 resulted in significantly less contraction versus skin graft only controls with no statistically significant difference among laser therapy groups. Scars treated with both PDL and FX CO 2 were visually more erythematous than other groups with a significant increase in redness between two and three standard deviations above normal skin redness. Scars treated with FX CO 2 were visually smoother and contained significantly fewer wrinkles. In addition, hyperpigmentation was significantly reduced in scars treated with FX CO 2 . The use of fractional carbon dioxide or pulsed dye laser therapy within 1 month of autografting significantly reduced scar

Light and electron microscopic analysis of tattoos treated by Q-switched ruby laser

Energy Technology Data Exchange (ETDEWEB)

Taylor, C.R.; Anderson, R.R.; Gange, R.W.; Michaud, N.A.; Flotte, T.J. (Massachusetts General Hospital, Boston (USA))

1991-07-01

Short-pulse laser exposures can be used to alter pigmented structures in tissue by selective photothermolysis. Potential mechanisms of human tattoo pigment lightening with Q-switched ruby laser were explored by light and electron microscopy. Significant variation existed between and within tattoos. Electron microscopy of untreated tattoos revealed membrane-bound pigment granules, predominantly within fibroblasts and macrophages, and occasionally in mast cells. These granules contained pigment particles ranging from 2-in diameter. Immediately after exposure, dose-related injury was observed in cells containing pigment. Some pigment particles were smaller and lamellated. At fluences greater than or equal to 3 J/cm2, dermal vacuoles and homogenization of collagen bundles immediately adjacent to extracellular pigment were occasionally observed. A brisk neutrophilic infiltrate was apparent by 24 h. Eleven days later, the pigment was again intracellular. Half of the biopsies at 150 d revealed a mild persistent lymphocytic infiltrate. There was no fibrosis except for one case of clinical scarring. These findings confirm that short-pulse radiation can be used to selectively disrupt cells containing tattoo pigments. The physial alteration of pigment granules, redistribution, and elimination appear to account for clinical lightening of the tattoos.

Enhancing hair follicle regeneration by nonablative fractional laser: Assessment of irradiation parameters and tissue response.

Science.gov (United States)

Wu, Yueh-Feng; Wang, Shiou-Han; Wu, Pei-Shan; Fan, Sabrina Mai-Yi; Chiu, Hsien-Yi; Tsai, Tsung-Hua; Lin, Sung-Jan

2015-04-01

Identification of methods to enhance anagen entry can be helpful for alopecia. Recently, nonablative laser has been proposed as a potential treatment for alopecia. However, how the laser parameters affect stem cell activity, hair cycles and the associated side effects have not been well characterized. Here we examine the effects of irradiation parameters of 1,550-nm fractional laser on hair cycles. The dorsal skin of eight-week-old female C57BL/6 mice with hair follicles in synchronized telogen was shaved and irradiated with a 1,550-nm fractional erbium-glass laser (Fraxel RE:STORE (SR1500) Laser System, Solta Medical, U.S.A.) with varied beam energies (5-35 mJ) and beam densities (500-3500 microthermal zones/cm(2) ). The cutaneous changes were evaluated both grossly and histologically. Hair follicle stem cell activity was detected by BrdU incorporation and changes in gene expression were quantified by real-time PCR. Direct thermal injury to hair follicles could be observed early after irradiation, especially at higher beam energy. Anagen induction in the irradiated skin showed an all-or-non change. Anagen induction and ulcer formation were affected by the combination of beam energy and density. The lowest beam energy of 5 mJ failed to promote anagen entry at all beam densities tested. As beam energy increased from 10 mJ to 35 mJ, we found a decreasing trend of beam density that could induce anagen entry within 7-9 days with activation of hair follicle stem cells. Beam density above the pro-regeneration density could lead to ulcers and scarring followed by anagen entry in adjacent skin. Analysis of inflammatory cytokines, including TNF-α, IL-1β, and IL-6, revealed that transient moderate inflammation was associated with anagen induction and intense prolonged inflammation preceded ulcer formation. To avoid side effects of hair follicle injury and scarring, appropriate combination of beam energy and density is required. Parameters outside the therapeutic

Comparison of a fractional microplasma radio frequency technology and carbon dioxide fractional laser for the treatment of atrophic acne scars: a randomized split-face clinical study.

Science.gov (United States)

Zhang, Zhen; Fei, Ye; Chen, Xiangdong; Lu, Wenli; Chen, Jinan

2013-04-01

No studies have compared fractional microplasma radio frequency (RF) technology with the carbon dioxide fractional laser system (CO2 FS) in the treatment of atrophic acne scars in the same patient. To compare the efficacy and safety of fractional microplasma RF with CO2 FS in the treatment of atrophic acne scars. Thirty-three Asian patients received three sessions of a randomized split-face treatment of fractional microplasma RF or CO2 FS. Both modalities had a roughly equivalent effect. Échelle d'Évaluation Clinique Des Cicatrices d'Acné scores were significantly lower after fractional microplasma RF (from 51.1 ± 14.2 to 22.3 ± 8.6, 56.4% improvement) and CO2 FS (from 48.8 ± 15.1 to 19.9 ± 7.9, 59.2% improvement) treatments. There was no statistically significant difference between the two therapies. Twelve subjects (36.4%) experienced postinflammatory hyperpigmentation (PIH) after 30 of 99 treatment sessions (30.3%) on the CO2 FS side and no PIH was observed on the fractional microplasma RF sides. Both modalities have good effects on treating atrophic scars. PIH was not seen with the fractional microplasma RF, which might make it a better choice for patients with darker skin. © 2013 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

Efficacy of autologous platelet-rich plasma combined with fractional ablative carbon dioxide resurfacing laser in treatment of facial atrophic acne scars: A split-face randomized clinical trial

OpenAIRE

Gita Faghihi; Shima Keyvan; Ali Asilian; Saeid Nouraei; Shadi Behfar; Mohamad Ali Nilforoushzadeh

2016-01-01

Background: Autologous platelet-rich plasma has recently attracted significant attention throughout the medical field for its wound-healing ability. Aims: This study was conducted to investigate the potential of platelet-rich plasma combined with fractional laser therapy in the treatment of acne scarring. Methods: Sixteen patients (12 women and 4 men) who underwent split-face therapy were analyzed in this study. They received ablative fractional carbon dioxide laser combined with intradermal ...

2940-nm Er:YAG fractional laser enhanced the effect of topical drug for psoriasis.

Science.gov (United States)

Li, Ruilian; Zhou, Jun; Su, Hui; Wang, Mei; Wang, Yongxian; Xiao, Shengxiang; Ma, Huiqun

2017-08-01

We observed the promoting effects of the 2940-nm erbium:YAG (Er:YAG) fractional laser in topical drug delivery for psoriasis. A total of five (four males and one female) recalcitrant psoriasis patients were given laser treatment eight times at 1-week intervals with the following parameters: 5-11% spot density and 100-μm energy depth. The psoriatic skin lesions on the left knee and the corresponding lesions at the right ones of each psoriasis patient were randomly divided into two groups: laser + topical drug group (L) and drug alone group (D). The psoriatic lesions in both groups were treated with the same topical treatment (calcipotriol ointment). The corresponding psoriatic lesions in the L group received extra 2940-nm Er:YAG laser irradiation before topical treatment. The photos of psoriatic lesions were taken before each treatment. The final photos were obtained from the patients at the seventh day after the final treatment. Drug alone or in combination with laser Er:YAG both reduced psoriatic lesions. However, with the increase in the number of treatments, increasing differences were observed between the treatment and the control sides. The therapeutic outcomes in the L groups were better than those in the D groups. Psoriasis area and severity index (PASI) scores for five cases of both groups were decreased. However, the scores in the L groups were lower than those in the D groups. The use of 2940 nm Er:YAG promoted the absorption of topical drugs for psoriasis, improving the therapeutic effect.

Tunable diode laser absorption spectroscopy-based tomography system for on-line monitoring of two-dimensional distributions of temperature and H{sub 2}O mole fraction

Energy Technology Data Exchange (ETDEWEB)

Xu, Lijun, E-mail: lijunxu@buaa.edu.cn; Liu, Chang; Jing, Wenyang; Cao, Zhang [School of Instrument Science and Opto-Electronic Engineering, Beihang University, Beijing 100191 (China); Ministry of Education’s Key Laboratory of Precision Opto-Mechatronics Technology, Beijing 100191 (China); Xue, Xin; Lin, Yuzhen [School of Energy and Power Engineering, Beihang University, Beijing 100191 (China)

2016-01-15

To monitor two-dimensional (2D) distributions of temperature and H{sub 2}O mole fraction, an on-line tomography system based on tunable diode laser absorption spectroscopy (TDLAS) was developed. To the best of the authors’ knowledge, this is the first report on a multi-view TDLAS-based system for simultaneous tomographic visualization of temperature and H{sub 2}O mole fraction in real time. The system consists of two distributed feedback (DFB) laser diodes, a tomographic sensor, electronic circuits, and a computer. The central frequencies of the two DFB laser diodes are at 7444.36 cm{sup −1} (1343.3 nm) and 7185.6 cm{sup −1} (1391.67 nm), respectively. The tomographic sensor is used to generate fan-beam illumination from five views and to produce 60 ray measurements. The electronic circuits not only provide stable temperature and precise current controlling signals for the laser diodes but also can accurately sample the transmitted laser intensities and extract integrated absorbances in real time. Finally, the integrated absorbances are transferred to the computer, in which the 2D distributions of temperature and H{sub 2}O mole fraction are reconstructed by using a modified Landweber algorithm. In the experiments, the TDLAS-based tomography system was validated by using asymmetric premixed flames with fixed and time-varying equivalent ratios, respectively. The results demonstrate that the system is able to reconstruct the profiles of the 2D distributions of temperature and H{sub 2}O mole fraction of the flame and effectively capture the dynamics of the combustion process, which exhibits good potential for flame monitoring and on-line combustion diagnosis.

Fractional CO₂ laser treatment of caesarean section scars

DEFF Research Database (Denmark)

Karmisholt, Katrine E; Taudorf, Elisabeth H; Wulff, Camilla B

2017-01-01

BACKGROUND AND OBJECTIVES: Caesarean section (c-section) scars can be pose functional and cosmetic challenges and ablative fractional laser (AFXL) treatment may offer benefit to patients. We evaluated textural and color changes over time in AFXL-treated versus untreated control scars. MATERIALS...... AND METHODS: A randomized, controlled, intra-individual split-scar trial with three sessions of AFXL-treatments for mature c-section scars. Settings of AFXL were adjusted to each individual scar. End-points were blinded on-site clinical evaluations at 1, 3, and 6 months follow-up (Patient and Observer Scar...... Assessment Scale [POSAS] and Vancouver Scar Scale [VSS]), blinded photo-evaluations, reflectance measurements, tissue histology, and patients satisfaction. RESULTS: Eleven of 12 patients completed the study. At 1 month follow-up, AFXL-treated scars were significantly improved in pliability (POSAS P = 0...

Evaluation of a Low Energy, Low Density, Non-Ablative Fractional 1927 nm Wavelength Laser for Facial Skin Resurfacing.

Science.gov (United States)

Brauer, Jeremy A; Alabdulrazzaq, Hamad; Bae, Yoon-Soo Cindy; Geronemus, Roy G

2015-11-01

We investigated the safety, tolerability and efficacy of a low energy low density, non-ablative fractional 1,927-nm laser in the treatment of facial photodamage, melasma, and post inflammatory hyperpigmentation. Prospective non-randomized trial. Single center, private practice with a dedicated research department. Subjects with clinically diagnosed facial photodamage, melasma, or post inflammatory hyperpigmentation. Subjects received four to six treatments at 14-day intervals (+/- 3 days) with a low energy low density non-ablative fractional 1,927-nm laser (Solta Hayward, CA) with an energy level of 5 mJ, and density coverage of either 5%, 7.5%, or 10%, with a total of up to 8 passes. Blinded assessment of clinical photos for overall improvement at one and three months post final treatment. Investigator improvement scores, and subject pain and satisfaction scores for overall improvement were recorded as well. We enrolled 23 subjects, average age 45.0 years (range, 25-64 years), 22 with Fitzpatrick Skin Types I-IV and 1 with Type VI, with facial photodamage, melasma, or post inflammatory hyperpigmentation. Approximately 55% of subjects reported marked to very significant improvement at one and three months post final treatment. Blinded assessment of photography of 20 subjects revealed an average of moderate improvement at one-month follow up and mild to moderate improvement at three months. Average subject pain score was 3.4/10 during treatment. Favorable outcomes were demonstrated using the low energy low density, non-ablative fractional 1,927-nm laser in facial resurfacing for photodamage, melasma, and post inflammatory hyperpigmentation. Results were maintained at the 3-month follow up, as demonstrated by investigator and subject assessments, as well as blinded evaluations by three independent dermatologists utilizing photographs obtained from a standardized facial imaging device.

Nonablative 1550-nm fractional laser therapy versus triple topical therapy for the treatment of melasma: A randomized controlled pilot study

NARCIS (Netherlands)

Kroon, Marije W.; Wind, Bas S.; Beek, Johan F.; van der Veen, J. P. Wietze; Nieuweboer-Krobotová, Ludmila; Bos, Jan D.; Wolkerstorfer, Albert

2011-01-01

Various treatments are currently available for melasma. However, results are often disappointing. We sought to assess the efficacy and safety of nonablative 1550-nm fractional laser therapy and compare results with those obtained with triple topical therapy (the gold standard). Twenty female

Quality assurance in fractionated stereotactic radiotherapy

International Nuclear Information System (INIS)

Warrington, A.P.; Laing, R.W.; Brada, M.

1994-01-01

The recent development of fractionated stereotactic radiotherapy (SRT), which utilises the relocatable Gill-Thomas-Cosman frame (GTC 'repeat localiser'), requires comprehensive quality assurance (QA). This paper focuses on those QA procedures particularly relevant to fractionated SRT treatments, and which have been derived from the technique used at the Royal Marsden Hospital. They primarily relate to the following: (i) GTC frame fitting, initially in the mould room, and then at each imaging session and treatment fraction; (ii) checking of the linear accelerator beam geometry and alignment lasers; and (iii) setting up of the patient for each fraction of treatment. The precision of the fractionated technique therefore depends on monitoring the GTC frame relocation at each fitting, checking the accuracy of the radiation isocentre of the treatment unit, its coincidence with the patient alignment lasers and the adjustments required to set the patient up accurately. The results of our quality control checks show that setting up to a mean radiation isocentre using precisely set-up alignment lasers can be achievable to within 1 mm accuracy. When this is combined with a mean GTC frame relocatability of 1 mm on the patient, a 2-mm allowance between the prescribed isodose surface and the defined target volume is a realistic safety margin for this technique

Use of fractional laser microablation of skin for improvement of its immersion clearing

Science.gov (United States)

Kolesnikova, Ekaterina A.; Kolesnikov, Aleksandr S.; Genina, Elina A.; Dolotov, Leonid E.; Tuchina, Darya K.; Bashkatov, Alexey N.; Tuchin, Valery V.

2013-02-01

We are proposing a new method for enhancement of optical clearing agent delivery into the skin using fractional laser microablation of the skin surface. The Palomar Lux2940 erbium laser with the wavelength 2940 nm and pulse duration of 5 ms was used as a light source. Two regimes of laser action were used in the experiments: the first one realized microablation of skin upper layer and the second one created microchannels in skin. As optical clearing agents mineral oil and PEG-300 were used. In vivo studies were carried out with white outbred rats. Both parameters: the permeability coefficient of the agents in the tissue and the optical probing depth were measured using the OCT system at a wavelength of 930 nm. The following values of the permeability coefficient of the skin with microablation were obtained: (3.41+/-0.46)×10-5 cm/s and (2.35+/-0.30)×10-5 cm/s for mineral oil and PEG-300, respectively, at the use of the surface microablation and (3.32+/-0.09)×10-5 cm/s and (3.61+/-0.34)×10-5 cm/s for mineral oil and PEG-300, respectively, at the use of the microporation. The results have shown that the joint application of mineral oil with microablation in the first regime promotes maximal (nearly 2-folds) increasing of optical probing depth in 30 min. Obtained data can be used for development of optical diagnostic methods of skin diseases.

Current role of resurfacing lasers.

Science.gov (United States)

Hantash, B M; Gladstone, H B

2009-06-01

Resurfacing lasers have been the treatment of choice for diminishing rhytids and tightening skin. The carbon dioxide and erbium lasers have been the gold and silver standards. Despite their effectiveness, these resurfacing lasers have a very high risk profile including scarring, hyperpigmentation and hypopigmentation. Because of these side effects, various practitioners have tried alternative settings for these lasers as well as alternative wavelengths, particularly in the infrared spectrum. These devices have had less downtime, but their effectiveness has been limited to fine wrinkles. As with selective photothemolysis, a major advance in the field has been fractionated resurfacing which incorporates grids of microthermal zones that spares islands of skin. This concept permits less tissue damage and quicker tissue regeneration. Initially, fractionated resurfacing was limited to the nonablative mid-infrared spectrum. These resurfacing lasers is appropriate for those patients with acne scars, uneven skin tone, mild to moderate photodamage, and is somewhat effective for melasma. Importantly, because there is less overall tissue damage and stimulation of melanocytes, these lasers can be used in darker skin types. Downtime is 2-4 days of erythema and scaling. Yet, these nonablative fractionated devices required 5-6 treatments to achieve a moderate effect. Logically, the fractionated resurfacing has now been applied to the CO2 and the Erbium:Yag lasers. These devices can treat deeper wrinkles and tighten skin. Downtime appears to be 5-7 days. The long term effectiveness and the question of whether these fractionated devices will approach the efficacy of the standard resurfacing lasers is still in question. Ultimately either integrated devices which may use fractionated resurfacing, radiofrequency and a sensitizer, or combining different lasers in a single treatment may prove to be the most effective in reducing rhtyides, smoothing the skin topography and tightening the

The Effect of Neodymium: Yttrium Aluminum Garnet and Fractional Carbon Dioxide Lasers on Alopecia Areata: A Prospective Controlled Clinical Trial.

Science.gov (United States)

Yalici-Armagan, Basak; Elcin, Gonca

2016-04-01

Effective treatment options for alopecia areata (AA) are missing. Whether lasers might be effective is a topic of debate. We aimed to evaluate whether neodymium: yttrium aluminum garnet (Nd:YAG) or fractional carbon dioxide lasers might stimulate the development of new hair. Thirty-two patients who had long-standing and treatment refractory diseases were recruited for the study. Three different patches on the scalp were selected, 1 of which served as control. The mean outcome measure was the hair count, which was calculated with the digital phototrichogram. Response was defined as at least 25% increase in the mean hair count at the treated patch compared with the control patch. At the end of the study, there was no statistically significant difference in the mean hair count for the 3 patches. In 7 of 32 patients (22%), an increase in the mean hair count was observed on the whole scalp including the control patch, which resulted in an improved Severity of Alopecia Tool (SALT) score. We have observed that Nd:YAG or fractional carbon dioxide lasers did not increase the mean hair count on the treated AA patches when compared with the control patch. However, an SALT score improvement in 22% of the patients suggested spontaneous remission.

Effect of combination of fractional CO2 laser and narrow-band ultraviolet B versus narrow-band ultraviolet B in the treatment of non-segmental vitiligo.

Science.gov (United States)

El-Zawahry, Mohamed Bakr; Zaki, Naglaa Sameh; Wissa, Marian Youssry; Saleh, Marwah Adly

2017-12-01

The present study was designed to evaluate the effect of combining fractional CO 2 laser with narrow-band ultraviolet B (NB-UVB) versus NB-UVB in the treatment of non-segmental vitiligo. The study included 20 patients with non-segmental stable vitiligo. They were divided into two groups. Group I received a single session of fractional CO 2 laser therapy on the right side of the body followed by NB-UVB phototherapy twice per week for 8 weeks. Group II received a second session of fractional CO 2 laser therapy after 4 weeks from starting treatment with NB-UVB. The vitiligo lesions were assessed before treatment and after 8 weeks of treatment by VASI. At the end of the study period, the vitiligo area score index (VASI) in group I decreased insignificantly on both the right (-2.6%) and left (-16.4%) sides. In group II, VASI increased insignificantly on the right (+14.4%) and left (+2.5%) sides. Using Adobe Photoshop CS6 extended program to measure the area of vitiligo lesions, group I showed a decrease of -1.02 and -6.12% in the mean area percentage change of vitiligo lesions on the right and left sides, respectively. In group II the change was +9.84 and +9.13% on the right and left sides, respectively. In conclusion, combining fractional CO 2 laser with NB-UVB for the treatment of non-segmental vitiligo did not show any significant advantage over treatment with NB-UVB alone. Further study of this combination for longer durations in the treatment of vitiligo is recommended.

Nonablative Fractional Laser Resurfacing for Acne Scarring in Patients With Fitzpatrick Skin Phototypes IV-VI.

Science.gov (United States)

Alexis, Andrew F; Coley, Marcelyn K; Nijhawan, Rajiv I; Luke, Janiene D; Shah, Sejal K; Argobi, Yahya A; Nodzenski, Michael; Veledar, Emir; Alam, Murad

2016-03-01

There is a paucity of studies investigating laser resurfacing in Fitzpatrick skin phototypes (SPT) IV to VI. To assess the efficacy and safety of fractional nonablative laser resurfacing in the treatment of acne scarring in patients with SPT IV to VI. The authors conducted a randomized, investigator-blinded and rater-blinded, split-face comparative study of adults with SPT IV to VI and facial acne scars treated with 2 different density settings and the same fluence. Quantitative global scarring grading system (QGSGS) scores were significantly improved from baseline at 16 and 24 weeks (p = .0277). Improvements in QGSGS scores after higher and lower density treatments were statistically similar (p = .96). The live-blinded dermatologist, the blinded dermatologist photoraters, and the patients rated scars as being significantly more improved by visual analog scale at weeks 16 and 24 compared with baseline (p skin types IV to VI. Self-limited postinflammatory hyperpigmentation was a common occurrence, especially with higher treatment densities.

Combination of ablative fractional laser and daylight-mediated photodynamic therapy for actinic keratosis in organ transplant recipients – a randomized controlled trial

DEFF Research Database (Denmark)

Togsverd-Bo, Katrine; Lei, Ulrikke; Erlendsson, A M

2015-01-01

BACKGROUND: Topical photodynamic therapy (PDT) for actinic keratoses (AK) is hampered by pain during illumination and inferior efficacy in organ-transplant recipients (OTR). OBJECTIVES: We assessed ablative fractional laser (AFL)-assisted daylight photodynamic therapy (PDT) (AFL-dPDT) compared...

Laser and Light Treatments for Hair Reduction in Fitzpatrick Skin Types IV-VI: A Comprehensive Review of the Literature.

Science.gov (United States)

Fayne, Rachel A; Perper, Marina; Eber, Ariel E; Aldahan, Adam S; Nouri, Keyvan

2018-04-01

Unwanted facial and body hair presents as a common finding in many patients, such as females with hirsutism. With advances in laser and light technology, a clinically significant reduction in hair can be achieved in patients with light skin. However, in patients with darker skin, Fitzpatrick skin types (FST) IV-VI, the higher melanin content of the skin interferes with the proposed mechanism of laser-induced selective photothermolysis, which is to target the melanin in the hair follicle to cause permanent destruction of hair bulge stem cells. Many prospective and retrospective studies have been conducted with laser and light hair-removal devices, but most exclude patients with darkly pigmented skin, considering them a high-risk group for unwanted side effects, including pigmentation changes, blisters, and crust formation. We reviewed the published literature to obtain studies that focused on hair reduction for darker skin types. The existing literature for this patient population identifies longer wavelengths as a key element of the treatment protocol and indicates neodymium-doped yttrium aluminum garnet (Nd:YAG), diode, alexandrite, and ruby lasers as well as certain intense pulsed light sources for safe hair reduction with minimal side effects in patients with FST IV-VI, so long as energy settings and wavelengths are appropriate. Based on the findings in this review, safe and effective hair reduction for patients with FST IV-VI is achievable under proper treatment protocols and energy settings.

Laser Resurfacing Pearls

OpenAIRE

Shah, Sonia; Alam, Murad

2012-01-01

Ablative skin resurfacing using the carbon dioxide laser was long considered the gold standard for treatment of photoaging, acne scars, and rhytids. However, conventional full-face carbon dioxide resurfacing is associated with significant risk of side effects and a prolonged postoperative recovery period. Fractional resurfacing has recently revolutionized laser surgery by offering close to comparable results with minimal side effects and a more rapid recovery. Although fractional devices have...

Laser based thermo-conductometry as an approach to determine ribbon solid fraction off-line and in-line.

Science.gov (United States)

Wiedey, Raphael; Šibanc, Rok; Kleinebudde, Peter

2018-06-06

Ribbon solid fraction is one of the most important quality attributes during roll compaction/dry granulation. Accurate and precise determination is challenging and no in-line measurement tool has been generally accepted, yet. In this study, a new analytical tool with potential off-line as well as in-line applicability is described. It is based on the thermo-conductivity of the compacted material, which is known to depend on the solid fraction. A laser diode was used to punctually heat the ribbon and the heat propagation monitored by infrared thermography. After performing a Gaussian fit of the transverse ribbon profile, the scale parameter σ showed correlation to ribbon solid fraction in off-line as well as in-line studies. Accurate predictions of the solid fraction were possible for a relevant range of process settings. Drug stability was not affected, as could be demonstrated for the model drug nifedipine. The application of this technique was limited when using certain fillers and working at higher roll speeds. This study showed the potentials of this new technique and is a starting point for additional work that has to be done to overcome these challenges. Copyright © 2018 Elsevier B.V. All rights reserved.

Successful Treatment of Tattoo-Induced Pseudolymphoma with Sequential Ablative Fractional Resurfacing Followed by Q-Switched Nd: YAG 532 nm Laser

Science.gov (United States)

Lucinda, Tan Siyun; Hazel, Oon Hwee Boon; Joyce, Lee Siong Siong; Hon, Chua Sze

2013-01-01

Decorative tattooing has been linked with a range of complications, with pseudolymphoma being unusual and challenging to manage. We report a case of tattoo-induced pseudolymphoma, who failed treatment with potent topical and intralesional steroids. She responded well to sequential treatment with ablative fractional resurfacing (AFR) followed by Q-Switched (QS) Nd:YAG 532 nm laser. Interestingly, we managed to document the clearance of her tattoo pigments after laser treatments on histology and would like to highlight the use of special stains such as the Grocott's Methenamine Silver (GMS) stain as a useful method to assess the presence of tattoo pigment in cases where dense inflammatory infiltrates are present. PMID:24470721

Q-switched ruby laser irradiation of normal human skin. Histologic and ultrastructural findings.

Science.gov (United States)

Hruza, G J; Dover, J S; Flotte, T J; Goetschkes, M; Watanabe, S; Anderson, R R

1991-12-01

The Q-switched ruby laser is used for treatment of tatoos. The effects of Q-switched ruby laser pulses on sun-exposed and sun-protected human skin, as well as senile lentigines, were investigated with clinical observation, light microscopy, and transmission electron microscopy. A pinpricklike sensation occurred at radiant exposures as low as 0.2 J/cm2. Immediate erythema, delayed edema, and immediate whitening occurred with increasing radiant exposure. The threshold for immediate whitening varied inversely with skin pigmentation, ranging from a mean of 1.4 J/cm2 in lentigines to 3.1 J/cm2 in sun-protected skin. Transmission electron microscopy showed immediate alteration of mature melanosomes and nuclei within keratinocytes and melanocytes, but stage I and II melanosomes were unaffected. Histologically, immediate injury was confined to the epidermis. There was minimal inflammatory response 1 day after exposure. After 1 week, subthreshold exposures induced hyperpigmentation, with epidermal hyperplasia and increased melanin staining noted histologically. At higher radiant exposures, hypopigmentation occurred with desquamation of a pigmented scale/crust. All sites returned to normal skin color and texture without scarring within 3 to 6 months. These observations suggest that the human skin response to selective photothermolysis of pigmented cells is similar to that reported in animal models, including low radiant exposure stimulation of melanogenesis and high radiant exposure lethal injury to pigmented epidermal cells.

Effects of morphology and wavelength on the measurement accuracy of soot volume fraction by laser extinction

Science.gov (United States)

Wang, Ya-fei; Huang, Qun-xing; Wang, Fei; Chi, Yong; Yan, Jian-hua

2018-01-01

A novel method to evaluate the quantitative effects of soot morphology and incident wavelength on the measurement accuracy of soot volume fraction, by the laser extinction (LE) technique is proposed in this paper. The results indicate that the traditional LE technique would overestimate soot volume fraction if the effects of morphology and wavelength are not considered. Before the agglomeration of isolated soot primary particles, the overestimation of the LE technique is in the range of 2-20%, and rises with increasing primary particle diameter and with decreasing incident wavelength. When isolated primary particles are agglomerated into fractal soot aggregates, the overestimation would exceed 30%, and rise with increasing primary particle number per soot aggregate, fractal dimension and fractal prefactor and with decreasing incident wavelength to a maximum value of 55%. Finally, based on these results above, the existing formula of the LE technique gets modified, and the modification factor is 0.65-0.77.

Fractional carbon dioxide laser for the treatment of facial atrophic acne scars: prospective clinical trial with short and long-term evaluation.

Science.gov (United States)

Elcin, Gonca; Yalici-Armagan, Basak

2017-12-01

The aim of this study was to evaluate the efficacy and safety of fractional carbon dioxide laser for the treatment of acne scars. Thirty-one participants, 15 female and 16 male, whose mean age was 34.84 ± 10.94 years, were included in this prospective study. The study took place between 2012 and 2016. Participants were evaluated with the "ECCA Grading Scale" before the first session, 3 months (short-term evaluation) and 3 years after the last session (long-term evaluation). Participants received two or three treatment sessions at 4-week intervals, with a 10,600 nm fractional carbon dioxide laser with pulse energies ranging between 100 and 160 mJ, 120 spot type, 75-100 spot/cm 2 density, and 30 W power. Self-assessments by the participants were done 3 months and 3 years after the last session. The mean ECCA score was 107.90 ± 39.38 before the first session, and 82.17 ± 36.23 at the time of short-term evaluation (p = 0.000). The grade of improvement at the short-term evaluation was as follows: no improvement, mild, moderate, and significant improvement for 7 (22.6%), 11 (35.5%), 9 (29%), and 4 (12.9%) of the participants, respectively. Regarding self-assessments, 80.6 and 61.3% of the participants rated themselves as having at least mild improvement at the short-term and the long-term follow-up periods, respectively. The results of this study suggest that fractional carbon dioxide laser is an efficient treatment option for acne scars. Furthermore, self-assessment results show that more than half of the participants still experience at least mild improvement at the end of 3 years.

Safe and effective one-session fractional skin resurfacing using a carbon dioxide laser device in super-pulse mode: a clinical and histologic study.

Science.gov (United States)

Trelles, Mario A; Shohat, Michael; Urdiales, Fernando

2011-02-01

Carbon dioxide (CO(2)) laser ablative fractional resurfacing produces skin damage, with removal of the epidermis and variable portions of the dermis as well as associated residual heating, resulting in new collagen formation and skin tightening. The nonresurfaced epidermis helps tissue to heal rapidly, with short-term postoperative erythema. The results for 40 patients (8 men and 32 women) after a single session of a fractional CO(2) resurfacing mode were studied. The treatments included resurfacing of the full face, periocular upper lip, and residual acne scars. The patients had skin prototypes 2 to 4 and wrinkle degrees 1 to 3. The histologic effects, efficacy, and treatment safety in various clinical conditions and for different phototypes are discussed. The CO(2) laser for fractional treatment is used in super-pulse mode. The beam is split by a lens into several microbeams, and super-pulse repetition is limited by the pulse width. The laser needs a power adaptation to meet the set fluence per microbeam. Laser pulsing can operate repeatedly on the same spot or be moved randomly over the skin, using several passes to achieve a desired residual thermal effect. Low, medium, and high settings are preprogrammed in the device, and they indicate the strength of resurfacing. A single treatment was given with the patient under topical anesthesia. However, the anesthesia was injected on areas of scar tissue. Medium settings (2 Hz, 30 W, 60 mJ) were used, and two passes were made for dark skins and degree 1 wrinkles. High settings (2 Hz, 60 W, 120 mJ) were used, and three passes were made for degree 3 wrinkles and scar tissue. Postoperatively, resurfaced areas were treated with an ointment of gentamycin, Retinol Palmitate, and DL-methionine (Novartis; Farmaceutics, S.A., Barcelona, Spain). Once epithelialization was achieved, antipigment and sun protection agents were recommended. Evaluations were performed 15 days and 2 months after treatment by both patients and

Quantifying uncertainty in soot volume fraction estimates using Bayesian inference of auto-correlated laser-induced incandescence measurements

Science.gov (United States)

Hadwin, Paul J.; Sipkens, T. A.; Thomson, K. A.; Liu, F.; Daun, K. J.

2016-01-01

Auto-correlated laser-induced incandescence (AC-LII) infers the soot volume fraction (SVF) of soot particles by comparing the spectral incandescence from laser-energized particles to the pyrometrically inferred peak soot temperature. This calculation requires detailed knowledge of model parameters such as the absorption function of soot, which may vary with combustion chemistry, soot age, and the internal structure of the soot. This work presents a Bayesian methodology to quantify such uncertainties. This technique treats the additional "nuisance" model parameters, including the soot absorption function, as stochastic variables and incorporates the current state of knowledge of these parameters into the inference process through maximum entropy priors. While standard AC-LII analysis provides a point estimate of the SVF, Bayesian techniques infer the posterior probability density, which will allow scientists and engineers to better assess the reliability of AC-LII inferred SVFs in the context of environmental regulations and competing diagnostics.

Laser-photophoretic migration and fractionation of human blood cells

International Nuclear Information System (INIS)

Monjushiro, Hideaki; Tanahashi, Yuko; Watarai, Hitoshi

2013-01-01

Graphical abstract: -- Highlights: •RBCs were migrated faster than WBCs and blood pellets by laser photophoresis. •Photophoretic efficiency of RBC and WBC was simulated by the Mie scattering theory. •Spontaneous orientation of RBC parallel to the migration direction was elucidated. •Laser photophoretic separation of RBC and WBC was possible in a tip flow system. -- Abstract: Laser photophoretic migration behavior of human blood cells in saline solution was investigated under the irradiation of Nd:YAG laser beam (532 nm) in the absence and the presence of the flow in a fused silica capillary. Red blood cells (RBC) were migrated faster than white blood cells (WBC) and blood pellets to the direction of propagation of laser light. The observed photophoretic velocity of RBC was about 11 times faster than those of others. This was understood from the larger photophoretic efficiency of RBC than that of WBC, which was simulated based on the Mie scattering theory. Furthermore, it was found that, during the photophoretic migration, RBCs spontaneously orientated parallel to the migration direction so as to reduce the drag force. Finally, it was demonstrated that RBC and WBC were separated in a micro-channel flow system by the laser photophoresis

Laser-photophoretic migration and fractionation of human blood cells

Energy Technology Data Exchange (ETDEWEB)

Monjushiro, Hideaki; Tanahashi, Yuko; Watarai, Hitoshi, E-mail: watarai@chem.sci.osaka-u.ac.jp

2013-05-13

Graphical abstract: -- Highlights: •RBCs were migrated faster than WBCs and blood pellets by laser photophoresis. •Photophoretic efficiency of RBC and WBC was simulated by the Mie scattering theory. •Spontaneous orientation of RBC parallel to the migration direction was elucidated. •Laser photophoretic separation of RBC and WBC was possible in a tip flow system. -- Abstract: Laser photophoretic migration behavior of human blood cells in saline solution was investigated under the irradiation of Nd:YAG laser beam (532 nm) in the absence and the presence of the flow in a fused silica capillary. Red blood cells (RBC) were migrated faster than white blood cells (WBC) and blood pellets to the direction of propagation of laser light. The observed photophoretic velocity of RBC was about 11 times faster than those of others. This was understood from the larger photophoretic efficiency of RBC than that of WBC, which was simulated based on the Mie scattering theory. Furthermore, it was found that, during the photophoretic migration, RBCs spontaneously orientated parallel to the migration direction so as to reduce the drag force. Finally, it was demonstrated that RBC and WBC were separated in a micro-channel flow system by the laser photophoresis.

The effect of pre-operative topical anaesthetic cream on the ablative width and coagulative depth of ablative fractional resurfacing laser.

Science.gov (United States)

Punyaratabandhu, Preawphan; Wanitphakdeedecha, Rungsima; Pattanaprichakul, Penvadee; Sitthinamsuwan, Panitta; Phothong, Weeranut; Eimpunth, Sasima; Lohsiriwat, Visnu; Manuskiatti, Woraphong

2017-02-01

Topical anaesthetic cream (TAC) is commonly used as a pre-treatment of ablative fractional resurfacing (AFR) laser. Most of anaesthetic cream contains distilled water as major component. Therefore, pre-operative TAC may interfere the photothermal reaction in the skin treated with fractional carbon-dioxide (FCO 2 ) laser and fractional erbium-doped yttrium aluminium garnet (FEr:YAG) laser. The objective of the study was to compare the ablative width (AW) and coagulative depth (CD) of AFR laser with and without pre-treatment with TAC. Four Thai females who underwent abdominoplasty were included in the study. The excised skin of each subject was divided into four areas. TAC (eutectic mixture of local anaesthesia; EMLA) with 1-h occlusion was applied only on the first and second areas. The first and third areas were treated with FCO 2 at 15 mj and 5% density. The second and fourth areas were treated with FEr:YAG at 28 J/cm 2 and 5% density. Six biopsied specimens were obtained from each area. A total of 96 specimens (24 specimens from each area) were collected from four patients and examined randomly by two dermatopathologists. The ablative width and coagulative depth from each specimen were determined. In FCO 2 -treated specimens, the mean AW of the specimens that were pre-treated with TAC and control was 174.86 ± 24.57 and 188.52 ± 41.32 μm. The mean CD of the specimens that were pre-treated with TAC and control was 594.96 ± 111.72 and 520.03 ± 147.40 μm. There were no significant differences in AW and CD between both groups (p = 0.53 and p = 0.15). In FEr:YAG-treated specimens, the mean AW of the specimens that were pre-treated with TAC and control was 381.11 ± 48.02 and 423.65 ± 60.16 μm. The mean CD of the specimens that were pre-treated with TAC and control was 86.03 ± 29.44 and 71.59 ± 18.99 μm. There were no significant differences in AW and CD between both groups (p = 0.16 and p = 0.24). The pre

Successful treatment of tattoo-induced pseudolymphoma with sequential ablative fractional resurfacing followed by Q-switched Nd: Yag 532 nm laser

Directory of Open Access Journals (Sweden)

Tan Siyun Lucinda

2013-01-01

Full Text Available Decorative tattooing has been linked with a range of complications, with pseudolymphoma being unusual and challenging to manage. We report a case of tattoo-induced pseudolymphoma, who failed treatment with potent topical and intralesional steroids. She responded well to sequential treatment with ablative fractional resurfacing (AFR followed by Q-Switched (QS Nd:YAG 532 nm laser. Interestingly, we managed to document the clearance of her tattoo pigments after laser treatments on histology and would like to highlight the use of special stains such as the Grocott′s Methenamine Silver (GMS stain as a useful method to assess the presence of tattoo pigment in cases where dense inflammatory infiltrates are present.

Efficacy and safety of fractional carbon dioxide laser for treatment of unwanted facial freckles in phototypes II-IV: a pilot study.

Science.gov (United States)

El Zawahry, Bakr; Zaki, Naglaa; Hafez, Vanessa; Abdel Hay, Rania; Hay, Rania Abdel; Fahim, Aya

2014-11-01

Facial freckles are a cosmetic concern to Egyptians, particularly young females. Several therapeutic lines exist with variable response rates and limitations. Fractional carbon dioxide (FCO2) laser provides minimal ablation and therefore less down time and less side effects. The efficacy and safety of this laser technology have still not been studied in freckles. The aim of this study is to assess the efficacy and safety of FCO2 laser in the treatment of unwanted facial freckles in Egyptians. Twenty patients undergone a single session of FCO2 laser and then were followed up clinically a month later. Photographs were taken before treatment and at follow-up visit and were assessed by three blinded investigators. Percent of global improvement was measured on a 4-point grading scale. Patient's satisfaction and adverse events were recorded. Two patients (10 %) showed grade 1 improvement, while eight patients (40 %) showed grade 2 improvement. Nine patients (45 %) showed grade 3 improvement, and only one patient (5 %) showed grade 4 improvement. FCO2 laser resurfacing is effective and safe in treatment of facial freckles in skin phototypes II-IV. It can offer a more practical alternative to topical treatments, and a cheaper alternative to Q-switched lasers.

Laser resurfacing pearls.

Science.gov (United States)

Shah, Sonia; Alam, Murad

2012-08-01

Ablative skin resurfacing using the carbon dioxide laser was long considered the gold standard for treatment of photoaging, acne scars, and rhytids. However, conventional full-face carbon dioxide resurfacing is associated with significant risk of side effects and a prolonged postoperative recovery period. Fractional resurfacing has recently revolutionized laser surgery by offering close to comparable results with minimal side effects and a more rapid recovery. Although fractional devices have grown in popularity, and have essentially replaced traditional resurfacing, fractional resurfacing can still be a challenging modality to control precisely due to hardware variations across comparable devices, the range of settings that can be used, and patient-specific considerations. Certain precautions and rules of thumb can reduce the risk associated with fractional resurfacing, and increase the likelihood of a good outcome.

Combined Fractional Treatment of Acne Scars Involving Non-ablative 1,550-nm Erbium-glass Laser and Micro-needling Radiofrequency: A 16-week Prospective, Randomized Split-face Study

Directory of Open Access Journals (Sweden)

Hyuck Hoon Kwon

2017-06-01

Full Text Available An optimized therapeutic regimen involving a non-ablative fractionated laser or radiofrequency therapy for acne scars has not yet been established. To evaluate whether the combination of a non-ablative fractional laser (NAF and fractional micro-needling radiofrequency (FMR has clinical advantages for the treatment of atrophic acne scars compared with NAF alone, a 16-week prospective, randomized split-face study was performed. Each facial side of a patient was treated with 3 sessions of either NAF with FMR or NAF alone, with a 4-week interval between each session. Although both sides demonstrated significant decreases in the échelle d’évaluation clinique des cicatrices d’acné (ECCA score, the facial side treated using the combination regimen demonstrated greater improvement in ECCA score regarding degree and onset time than the NAF-treated side. Histopathological and immunohistochemical results confirmed the clinical findings. This study demonstrated that a combination regimen involving NAF and FMR could be a viable option with satisfactory efficacy.

Evaluating facial pores and skin texture after low-energy nonablative fractional 1440-nm laser treatments.

Science.gov (United States)

Saedi, Nazanin; Petrell, Kathleen; Arndt, Kenneth; Dover, Jeffrey

2013-01-01

The fractionated nonablative 1440-nm laser creates microscopic thermal wounds within the epidermis and the dermis and is used clinically to improve tone, texture, and color of skin. We sought to investigate the use of this device to treat facial pores and to improve skin texture. Twenty patients received 6 treatments at the highest tolerable energy level performed 2 weeks apart. Photographic assessments using the VISIA-CR (Canfield Scientific Inc, Fairfield, NJ) imaging system were performed. The pore score was calculated, which is the percentage of the skin surface that has detected pores. Subjective measurements (0-4 scale) were recorded by both the subject and investigator regarding pore appearance, skin texture, and overall skin appearance. Treatment discomfort was scored by patients (1-10 scale). After 6 treatments there was a significant reduction in pore score (P pore score at baseline was 2.059 ± 0.8 and 2 weeks after the final treatment it was 1.700 ± 0.8, resulting in a 17% average reduction in pore score. Study investigators reported average scores being 1.95 ± 0.3 for improved pore appearance and 2.75 ± 0.2 for improved overall appearance (0-4 scale). Subjects noted average scores of 1.9 ± 0.5 for improvement of the appearance of pores and 2.85 ± 0.4 for improvement of overall appearance (0-4 scale). The average discomfort score during treatments was reported to be 4.6 ± 0.1 (1-10 scale). There were no serious adverse effects or long-term side effects. Small sample size and limited follow-up are study limitations. A series of treatments with the nonablative low-energy fractional 1440-nm laser appears to be safe and effective for reducing detectable pores and improving overall skin appearance. Copyright © 2012 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

Novel treatment of Hori's nevus: A combination of fractional nonablative 2,940-nm Er:YAG and low-fluence 1,064-nm Q-switched Nd:YAG laser.

Science.gov (United States)

Tian, Brian Wei Cheng Anthony

2015-01-01

To demonstrate a combination laser therapy to treat Hori's nevus. A prospective study. A Singapore-based clinic. Five female patients, aged 30-46 years, with bilateral malar Hori's nevus. Photographs were taken before treatment and 1 month after laser treatment was completed. These were graded by three independent physicians. The patients were also asked to grade their treatment response subjectively. They were followed up for a total of 3 months after laser treatment to monitor recurrence. The fractional nonablative 2,940-nm Er:YAG laser with a fluence of 0.7 J/cm(2), spot size 12 mm, and frequency 15 Hz was used to perform a full-face single-pass treatment. Subsequently, a second pass and third pass over Hori's nevi were done bilaterally till the clinical endpoint of skin whitening. The 1,064-nm Q-switched (QS) Nd:YAG at a fluence of 2.0 J/cm(2), frequency 2 Hz, and 4-mm spot size was used to deliver multiple passes over Hori's nevus till erythema with mild petechiae appeared. We repeated the treatment once a week for 3 more consecutive weeks. All five patients had above 80% improvement in their pigmentation and two (skin type III) achieved complete 100% clearance. Based on the patients' subjective assessments, all five of them expressed satisfaction and felt that their pigmentation had improved. There were no complications noted. The fractional nonablative 2940 nm Er:YAG laser and Q-switched 1064nm laser Nd:YAG combination is an effective and safe treatment for Hori's nevus.

The efficacy of fractional carbon dioxide (CO2) laser combined with terbinafine hydrochloride 1% cream for the treatment of onychomycosis.

Science.gov (United States)

Shi, Jian; Li, Jin; Huang, He; Permatasari, Felicia; Liu, Juan; Xu, Yang; Wu, Di; Zhou, Bing-Rong; Luo, Dan

2017-10-01

Although systemic and topical antifungal agents are widely used to treat onychomycosis, oral medications can cause adverse effects and the efficacy of topical agents is not satisfying. Currently, laser treatment has been studied for its efficacy in the treatment of onychomycosis. Our study was aimed to evaluate the efficacy of fractional carbon dioxide (CO 2 ) laser treatment combined with terbinafine cream for 6 months in the treatment of onychomycosis and to analyze the influencing factors. A total of 30 participants (124 nails) with clinical and mycological diagnosis of onychomycosis received fractional CO 2 laser treatment at 2-week interval combined with terbinafine cream once daily for 6 months. The clinical efficacy rate (CER) was assessed from the percentage of fully normal-appearing nails or nails with ≤5% abnormal appearance, and the mycological clearance rate (MCR) was assessed from the percentage of nails with negative fungal microscopy. The CER was evaluated at 3 time points: at the end of treatment (58.9%), at 1 month after the last treatment (63.5%), and at 3 months after the last treatment (68.5%). The MCRs at 1 month and 3 months after the last treatment were 77.4 and 74.2%, respectively. The evaluation of influencing factors showed significantly higher CER (p terbinafine cream for 6 months was an effective and safe method for the treatment of onychomycosis. There were 5 factors that positively influenced the treatment outcome: age, clinical type of onychomycosis, nail thickness, involved nail, and species of fungus.

Ultracentrifugation for ultrafine nanodiamond fractionation

Science.gov (United States)

Koniakhin, S. V.; Besedina, N. A.; Kirilenko, D. A.; Shvidchenko, A. V.; Eidelman, E. D.

2018-01-01

In this paper we propose a method for ultrafine fractionation of nanodiamonds using the differential centrifugation in the fields up to 215000g. The developed protocols yield 4-6 nm fraction giving main contribution to the light scattering intensity. The desired 4-6 nm fraction can be obtained from various types of initial nanodiamonds: three types of detonation nanodiamonds differing in purifying methods, laser synthesis nanodiamonds and nanodiamonds made by milling. The characterization of the obtained hydrosols was conducted with Dynamic Light Scattering, Zeta potential measurements, powder XRD and TEM. According to powder XRD and TEM data ultracentrifugation also leads to a further fractionation of the primary diamond nanocrystallites in the hydrosols from 4 to 2 nm.

A New Void Fraction Measurement Method for Gas-Liquid Two-Phase Flow in Small Channels

Directory of Open Access Journals (Sweden)

Huajun Li

2016-01-01

Full Text Available Based on a laser diode, a 12 × 6 photodiode array sensor, and machine learning techniques, a new void fraction measurement method for gas-liquid two-phase flow in small channels is proposed. To overcome the influence of flow pattern on the void fraction measurement, the flow pattern of the two-phase flow is firstly identified by Fisher Discriminant Analysis (FDA. Then, according to the identification result, a relevant void fraction measurement model which is developed by Support Vector Machine (SVM is selected to implement the void fraction measurement. A void fraction measurement system for the two-phase flow is developed and experiments are carried out in four different small channels. Four typical flow patterns (including bubble flow, slug flow, stratified flow and annular flow are investigated. The experimental results show that the development of the measurement system is successful. The proposed void fraction measurement method is effective and the void fraction measurement accuracy is satisfactory. Compared with the conventional laser measurement systems using standard laser sources, the developed measurement system has the advantages of low cost and simple structure. Compared with the conventional void fraction measurement methods, the proposed method overcomes the influence of flow pattern on the void fraction measurement. This work also provides a good example of using low-cost laser diode as a competent replacement of the expensive standard laser source and hence implementing the parameter measurement of gas-liquid two-phase flow. The research results can be a useful reference for other researchers’ works.

A New Void Fraction Measurement Method for Gas-Liquid Two-Phase Flow in Small Channels.

Science.gov (United States)

Li, Huajun; Ji, Haifeng; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing; Wu, Guohua

2016-01-27

Based on a laser diode, a 12 × 6 photodiode array sensor, and machine learning techniques, a new void fraction measurement method for gas-liquid two-phase flow in small channels is proposed. To overcome the influence of flow pattern on the void fraction measurement, the flow pattern of the two-phase flow is firstly identified by Fisher Discriminant Analysis (FDA). Then, according to the identification result, a relevant void fraction measurement model which is developed by Support Vector Machine (SVM) is selected to implement the void fraction measurement. A void fraction measurement system for the two-phase flow is developed and experiments are carried out in four different small channels. Four typical flow patterns (including bubble flow, slug flow, stratified flow and annular flow) are investigated. The experimental results show that the development of the measurement system is successful. The proposed void fraction measurement method is effective and the void fraction measurement accuracy is satisfactory. Compared with the conventional laser measurement systems using standard laser sources, the developed measurement system has the advantages of low cost and simple structure. Compared with the conventional void fraction measurement methods, the proposed method overcomes the influence of flow pattern on the void fraction measurement. This work also provides a good example of using low-cost laser diode as a competent replacement of the expensive standard laser source and hence implementing the parameter measurement of gas-liquid two-phase flow. The research results can be a useful reference for other researchers' works.

A review of laser and light therapy in melasma

Directory of Open Access Journals (Sweden)

M.K. Trivedi, BS, BA

2017-03-01

Full Text Available Melasma is a dysregulation of the homeostatic mechanisms that control skin pigmentation and excess pigment is produced. Traditional treatment approaches with topical medications and chemical peels are commonly used but due to the refractory and recurrent nature of melasma, patients often seek alternative treatment strategies such as laser and light therapy. Several types of laser and light therapy have been studied in the treatment of melasma. Intense pulsed light, low fluence Q-switched lasers, and non-ablative fractionated lasers are the most common lasers and light treatments that are currently performed. They all appear effective but there is a high level of recurrence with time and some techniques are associated with an increased risk for postinflammatory hyper- or hypopigmentation. The number and frequency of treatments varies by device type but overall, Q-switched lasers require the greatest number of treatment applications to see a benefit. Vascular-specific lasers do not appear to be effective for the treatment of melasma. Ablative fractionated lasers should be used with caution because they have a very high risk for postinflammatory hypo- and hyperpigmentation. The use of nonablative fractionated laser treatments compared with other laser and light options may result in slightly longer remission intervals. Picosecond lasers, fractional radiofrequency, and laser-assisted drug delivery are promising future approaches to treat melasma. The goal of this review is to summarize the efficacy and safety of the most commonly used laser and light therapies to treat melasma, briefly present future laser-based treatment options for patients with melasma, and provide recommendations for treatment on the basis of the reviewed information.

Advanced film-forming gel formula vs spring thermal water and white petrolatum as primary dressings after full-face ablative fractional CO2 laser resurfacing: a comparative split-face pilot study.

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Marini, L

2018-01-01

Aesthetically pleasing results and fast, uneventful recovery are highly desirable after rejuvenating ablative laser procedures. Wound dressings following ablative laser procedures should ideally improve and optimize the wound healing environment. The purpose of this comparative split-face, single-blinded, prospective observational study was to assess the efficacy and acceptability of two primary wound dressings immediately after a full-face fractional CO 2 laser resurfacing procedure. The assessments of an innovative film-forming dressing called Stratacel (SC) vs spring thermal water + Vaseline (V+) were conducted after a standardized, single-pass, full-face ablative fractional CO 2 laser skin resurfacing procedure. Clinical parameters, such as haemoglobin - HB; surface temperature - ST; micro-textural modifications - MT; superficial melanin - M; intrafollicular porphyrins - P, were assessed at different phases of the healing process using standardized, non-invasive technologies. Five female volunteers were enrolled in this inpatient, controlled pilot study. Most of the clinical parameters considered, including 3D surface texture analysis, revealed a better performance of SC vs. V+ during the early, more delicate phases of the healing process. This preliminary study, even if performed on a small number of volunteers, confirmed a definite advantage of the tested semipermeable film-forming formula (SC) over a more conventional postoperative skin care regime (V+). Clinical results could be explained by a better uniformity of distribution of SC over the micro-irregularities induced by ablative fractional CO 2 laser resurfacing. Its thin, semipermeable film might, in fact, act as an efficient, perfectly biocompatible, full contact, temporary skin barrier, able to protect extremely delicate healing surfaces from potential environmental irritations. © 2017 European Academy of Dermatology and Venereology.

Is the Fractional Laser Still Effective in Assisting Cutaneous Macromolecule Delivery in Barrier-Deficient Skin? Psoriasis and Atopic Dermatitis as the Disease Models.

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Lee, Woan-Ruoh; Shen, Shing-Chuan; Sung, Calvin T; Liu, Pei-Ying; Fang, Jia-You

2018-04-26

Most of the investigations into laser-assisted skin permeation have used the intact skin as the permeation barrier. Whether the laser is effective in improving cutaneous delivery via barrier-defective skin is still unclear. In this study, ablative (Er:YAG) and non-ablative (Er:glass) lasers were examined for the penetration of peptide and siRNA upon topical application on in vitro skin with a healthy or disrupted barrier. An enhanced peptide flux (6.9 fold) was detected after tape stripping of the pig stratum corneum (SC). A further increase of flux to 11.7 fold was obtained after Er:YAG laser irradiation of the SC-stripped skin. However, the application of Er:glass modality did not further raise the flux via the SC-stripped skin. A similar trend was observed in the case of psoriasiform skin. Conversely, the flux was enhanced 3.7 and 2.6 fold after treatment with the Er:YAG and the Er:glass laser on the atopic dermatitis (AD)-like skin. The 3-D skin structure captured by confocal microscopy proved the distribution of peptide and siRNA through the microchannels and into the surrounding tissue. The fractional laser was valid for ameliorating macromolecule permeation into barrier-disrupted skin although the enhancement level was lower than that of normal skin.

In vivo and ex vivo characterization of a novel Er fiber laser system for fractional treatment of soft oral tissues

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Shatilova, Ksenia; Aloian, Georgii; Karabut, Maria; Ryabova, Valentina; Yaroslavsky, Ilya V.; Altshuler, Gregory

2018-02-01

In this work, we present the first histological in vivo and ex vivo study of effects of fractional Er fiber laser (wavelength 1550 nm, peak power 25 W) on keratinized gum and alveolar mucosa for gum regeneration. Biopsy with subsequent NBTC staining was used as primary evaluation technique. Ex vivo, porcine tissue model was used. Effects of pulse energy, beam diameter, and beam divergence were investigated in detail. It has been demonstrated that under optimal conditions columns up to 800 μm in depth could be reliably produced with 130 mJ pulses. Clinically, 2 subjects were treated and 4 punch biopsies were collected. The results were compared with ex vivo data. Both ex vivo and in vivo datasets suggest feasibility of a dental fractional system intended for gum regeneration.

Novel treatment of Hori′s nevus: A combination of fractional nonablative 2,940-nm Er:YAG and low-fluence 1,064-nm Q-switched Nd:YAG laser

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Brian Wei Cheng Anthony Tian

2015-01-01

Full Text Available Objective: To demonstrate a combination laser therapy to treat Hori′s nevus. Design: A prospective study. Setting: A Singapore-based clinic. Participants: Five female patients, aged 30-46 years, with bilateral malar Hori′s nevus. Measurements: Photographs were taken before treatment and 1 month after laser treatment was completed. These were graded by three independent physicians. The patients were also asked to grade their treatment response subjectively. They were followed up for a total of 3 months after laser treatment to monitor recurrence. Materials and Methods: The fractional nonablative 2,940-nm Er:YAG laser with a fluence of 0.7 J/cm 2, spot size 12 mm, and frequency 15 Hz was used to perform a full-face single-pass treatment. Subsequently, a second pass and third pass over Hori′s nevi were done bilaterally till the clinical endpoint of skin whitening. The 1,064-nm Q-switched (QS Nd:YAG at a fluence of 2.0 J/cm 2 , frequency 2 Hz, and 4-mm spot size was used to deliver multiple passes over Hori′s nevus till erythema with mild petechiae appeared. We repeated the treatment once a week for 3 more consecutive weeks. Results: All five patients had above 80% improvement in their pigmentation and two (skin type III achieved complete 100% clearance. Based on the patients′ subjective assessments, all five of them expressed satisfaction and felt that their pigmentation had improved. There were no complications noted. Conclusion: The fractional nonablative 2940 nm Er:YAG laser and Q-switched 1064nm laser Nd:YAG combination is an effective and safe treatment for Hori′s nevus.

Non-ablative fractional laser in conjunction with microneedle arrays for improved cutaneous vaccination

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Wang, Ji; Li, Bo; Wu, Mei X.

2015-03-01

Skin is more potent than the muscle for vaccination, but it is not a common site for immunization to date owing, in part, to a relatively high rate of pains and skin irritation and difficulty of administration. Here, we show effective and lesion free cutaneous vaccination by a combination of a biodegradable microneedle array (MNs) and an FDA-approved nonablative fractional laser (NAFL). Delivering a vaccine into many micropores, instead of a single "big" pore in the skin, effectively segregated vaccine-induced inflammation into many microzones and resulted in quick resolution of the inflammation, provided that distances between any two micropores were far enough. When the inoculation site was treated by NAFL prior to insertion of the MNs comprised of PR8 model influenza vaccine, the mice displayed vigorous antigen-uptake, giving rise to strong, Th1-biased immunity. The mice were protected from a challenge of homologous influenza virus at a high dose as well as heterologous H1N1 and H3N2 viruses. The adjuvant effect of NAFL was ascribed primarily to activation of the dsDNA sensing pathway by dsDNA released from laser-damaged skin cells. Thus, mice deficient in the dsDNA sensing pathway, but not toll like receptor (TLR) or inflammasome pathways, showed poor response to NAFL. Importantly, both mice and swine exhibited strong, protective immunity, but no overt skin reactions with this approach, in sharp contrast to intradermal injections that caused severe, overt skin reactions. The effective lesion-free transcutaneous vaccination merits further clinical studies.

Efficacy of a new fractional CO2 laser in the treatment of photodamage and acne scarring.

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Katz, Bruce

2010-01-01

This study evaluates the efficacy and safety of a novel fractional CO(2) laser device for improving facial rhytids, hyperpigmentation, enlarged pores, skin laxity, and acne scarring. Subjects (n= 15) were treated three to five times at 3-week intervals. Biopsy specimens were used to evaluate healing response and neocollagenesis. Clinical improvement was rated on a quartile rating scale from digital photographs. Subject discomfort during treatment was evaluated on a scale of 0 to 5. Fourteen subjects who completed the study achieved good to excellent improvement in overall appearance, with 60% rated excellent. Improvement in photodamage was good to excellent in 92% of subjects, and reduction in rhytids was good to excellent in 85%. A total of 79% of subjects achieved good to excellent improvement in pore sizes and skin laxity. Subject discomfort during treatment was 3.0 +/- 0.7. Erythema persisted for 2-3 days, and subjects resumed normal activities 1-2 days after the procedure. Histological slides after a single treatment showed new collagen formation. The SmartSkin fractional CO(2) system (Cynosure, Inc., Westford, MA, USA) provides significant improvement for the treatment of facial wrinkles, hyperpigmentation, pore size, and skin laxity associated with photodamage.

Objective evaluation of the efficacy of a non-ablative fractional 1565 nm laser for the treatment of deliberate self-harm scars.

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Guertler, Anne; Reinholz, Markus; Poetschke, Julian; Steckmeier, Stephanie; Schwaiger, Hannah; Gauglitz, Gerd G

2018-02-01

Scars resulting from deliberate self-harm (DSH) represent therapeutically challenging forms of scarring due to their highly variable patterns, with no official therapeutic guidelines available. In this pilot study, we aimed to evaluate the effectiveness and safety of a non-ablative fractional Er:glass 1565 nm laser, as a potential new, minimal-invasive approach for the improvement of DSH scars. Sixteen Caucasians suffering from mature DSH scars were included in this clinical study. Patients received a total of three treatments using a non-ablative fractional 1565 nm Er:glass laser every 4 weeks, employing two passes (300 μbeams/cm 2 , 40 mJ, onto the scar; 150 μbeams/cm 2 , 50 mJ, overall area). Measurements included questionnaires (DLQI, POSAS), digital photography, and objective three-dimensional analysis using PRIMOS and VECTRA software at baseline, 1 and 6 months after treatment. PRIMOS objective measurements showed highly significant changes in scar surface with a reduction of atrophic lesions by 27.5% at 6 months follow-up (FU), a decrease in scar height by 42.7% at 6 months FU, resulting in an overall diminished skin irregularity dropping from 678.3 μm at baseline to 441.6 μm throughout the course of the study (p = laser represents a promising and safe approach for the therapy of DSH scars. Although these scars will never fully resolve, their appearance can be significantly improved to a cosmetically and socially more acceptable appearance.

The fractional laser-induced coagulation zone characterized over time by laser scanning confocal microscopy-A proof of concept study.

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Banzhaf, Christina A; Lin, Lynlee L; Dang, Nhung; Freeman, Michael; Haedersdal, Merete; Prow, Tarl W

2018-01-01

Ablative fractional laser (AFXL) is an acknowledged technique to increase uptake of topical agents in skin. Micro thermal ablation zones (MAZs) consist of ablated vertical channels surrounded by a coagulation zone (CZ). Laser scanning confocal microscopy (LSCM) images individual MAZs at 733 nm (reflectance confocal microscopy (RCM)). Further, LSCM can image sodium fluorescein (NaF) fluorescence with 488 nm excitation (fluorescence confocal microcopy (FCM)), a small hydrophilic test molecule (370 MW, log P -1.52), which may simulate uptake, bio-distribution and kinetics of small hydrophilic drugs. To explore LSCM for combined investigations of CZ thickness and uptake, bio-distribution and kinetics of NaF in AFXL-exposed skin. Excised human abdominal skin samples were exposed to AFXL (15 mJ/microbeam, 2% density) and NaF gel (1000 μg/ml, 10 μl/cm2) in six repetitions, including untreated control samples. CZ thickness and spatiotemporal fluorescence intensities (FI) were quantified up to four hours after NaF application by RCM and FCM. Test sites were scanned to a depth of 200 μm, quantifying thickness of skin compartments (stratum corneum, epidermis, upper dermis), individual CZ thicknesses and FI in CZ and surrounding skin. RCM images established skin morphology to a depth of 200 μm. The CZ thickness measurements were feasible to a depth of 50 μm, and remained unchanged over time at 50 μm (P > 0.5). FI were detected to a depth of 160 μm and remained constant in CZ up to four hours after NaF application (15 minutes: 79 AU (73-92 AU), 60 minutes: 72 AU (58-82 AU), four hours: 78 AU (71-90 AU), P > 0.1). In surrounding skin, FI increased significantly over time, but remained lower than FI in CZ (15 minutes: 21 AU (17-22 AU), 60 minutes: 21 AU (19-26 AU), four hours: 42 (31- 48 AU), P = 0.03). AFXL-processed skin generated higher FI compared to non-laser processed skin in epidermis and upper dermis at 60 minutes and four hours

TEM investigations of laser ablated particles

International Nuclear Information System (INIS)

Fliegel, D.; Dundas, S.; Kosler, J.; Klementova, M.

2009-01-01

Full text: Laser ablation inductively coupled plasma mass spectrometry suffers from fractionation effects hindering a non matrix matched calibration strategy. Different reasons for elemental fractionation that are related to the laser ablation, the transport and the vaporization in the plasma are discussed. One major question to be addressed linked to the vaporization yield in the ICP is in which of mineralogical phase the different ablated particle sizes enter the plasma. This contribution will investigate particles generated by a 213 nm laser from different samples such as minerals and alloys with respect to their chemical and phase compositions using high resolution TEM. (author)

Mexametric and cutometric assessment of the signs of aging of the skin area around the eyes after the use of non-ablative fractional laser, non-ablative radiofrequency and intense pulsed light.

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Kołodziejczak, Anna Maria; Rotsztejn, Helena

2017-03-01

The assessment of the signs of aging within eyes area in cutometric (skin elasticity) and mexametric (discoloration and severity of erythema) examination after the treatment with: non-ablative fractional laser, non-ablative radiofrequency (RF) and intense light source (IPL). This study included 71 patients, aged 33-63 years (the average age was 45.81) with Fitzpatrick skin type II and III. 24 patients received 5 successive treatment sessions with a 1,410-nm non-ablative fractional laser in two-week intervals, 23 patients received 5 successive treatment sessions with a non-ablative RF in one-week intervals and 24 patients received 5 successive treatment sessions with an IPL in two-week intervals. The treatment was performed for the skin in the eye area. The Cutometer and Mexameter (Courage + Khazaka electronic) reference test was used as an objective method for the assessment of skin properties: elasticity, skin pigmentation and erythema. Measurements of skin elasticity were made in three or four sites within eye area. The results of cutometric measurements for R7 showed the improvement in skin elasticity in case of all treatment methods. The largest statistically significant improvement (p measurements and for all methods, the greatest improvement in skin elasticity was demonstrated between the first and second measurement (after 3rd procedures). The majority of the results of mexametric measurements-MEX (melanin level) and ERYT (the severity of erythema) are statistically insignificant. Fractional, non-ablative laser, non-ablation RF and intense light source can be considered as methods significantly affecting elasticity and to a lesser extent erythema and skin pigmentation around the eyes. Fractional non-ablative laser is a method which, in comparison to other methods, has the greatest impact on skin viscoelasticity. These procedures are well tolerated and are associated with a low risk of side effects. © 2017 Wiley Periodicals, Inc.

Use of a novel fractional CO2 laser for the treatment of genitourinary syndrome of menopause: 1-year outcomes.

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Sokol, Eric R; Karram, Mickey M

2017-07-01

To assess safety and efficacy of a fractional CO2 laser therapy for the treatment of genitourinary syndrome of menopause (GSM) with follow-up to 1 year posttreatment. Women presenting with GSM and meeting inclusion criterion were enrolled. Visual Analog Scales were used to grade vaginal pain, burning, itching, dryness, dyspareunia, and dysuria. Dilators were used to rate vaginal elasticity at baseline and at each follow-up visit. Before each treatment and at follow-up, Vaginal Health Index scoring and Female Sexual Function Index questionnaires were completed. Women received three vaginal laser treatments spaced 6 weeks apart. Participant satisfaction was measured on 5-point Likert scales (1 = very dissatisfied, 5 = very satisfied). Of 30 women (mean age 58.6 ± 8.8 years), three were lost to follow-up at 3 months and six at 1 year. None were discontinued or withdrew due to an adverse event. Average improvement in Visual Analog Scale scores for all symptom categories was statistically significant at 3 months and remained so through 1 year, except dysuria. Differences between data at 3 months and 1 year were not statistically significant, indicating persistence of positive outcomes. Average overall improvement in pain was 1.9 (±3.4), burning 1.9 (±3.1), itching 1.4 (±1.9), dryness 5.9 (±2.8), dyspareunia 4.9 (±3.3), and dysuria 0.9 (±3.1). Improvement in average Vaginal Health Index and Female Sexual Function Index scores was also statistically significant (P < 0.0001). Of 19 women undergoing dilator examination at 1 year, 18 (94.8%) were comfortable with the same or larger dilator size. Twenty-two of 24 women (92%) were satisfied or extremely satisfied with the treatment at 1 year. Based on study data up to 1 year, the fractional CO2 laser may be an effective and safe treatment for women suffering from symptoms of GSM, although additional studies with larger populations and placebo control is needed to confirm these results.

Use of fractional laser microablation and ultrasound to facilitate the delivery of gold nanoparticles into skin in vivo

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Terentyuk, G S; Genina, Elina A; Bashkatov, A N; Ryzhova, M V; Tsyganova, N A; Chumakov, D S; Khlebtsov, B N; Sazonov, A A; Dolotov, L E; Tuchin, Valerii V; Khlebtsov, Nikolai G; Inozemtseva, O A

2012-06-30

The delivery of gold nanoparticles (nanocages coated with a layer of silicon dioxide (40/20 nm)) dispersed in the solution (glycerol + polyethylene glycol-400, 1 : 1) into the skin tissue is studied experimentally in vivo. From the data of optical coherence tomography and histochemical analysis it follows that simple application of suspension of nanoparticles is not efficient enough for delivery of the particles into the skin as a result of passive diffusion. It is shown that fractional laser microablation of skin before the application of the suspension, followed by the topical treatment by ultrasound allows penetration through the epidermis layer and delivery of nanoparticles into dermis and hypodermis.

Use of fractional laser microablation and ultrasound to facilitate the delivery of gold nanoparticles into skin in vivo

International Nuclear Information System (INIS)

Terentyuk, G S; Genina, Elina A; Bashkatov, A N; Ryzhova, M V; Tsyganova, N A; Chumakov, D S; Khlebtsov, B N; Sazonov, A A; Dolotov, L E; Tuchin, Valerii V; Khlebtsov, Nikolai G; Inozemtseva, O A

2012-01-01

The delivery of gold nanoparticles (nanocages coated with a layer of silicon dioxide (40/20 nm)) dispersed in the solution (glycerol + polyethylene glycol-400, 1 : 1) into the skin tissue is studied experimentally in vivo. From the data of optical coherence tomography and histochemical analysis it follows that simple application of suspension of nanoparticles is not efficient enough for delivery of the particles into the skin as a result of passive diffusion. It is shown that fractional laser microablation of skin before the application of the suspension, followed by the topical treatment by ultrasound allows penetration through the epidermis layer and delivery of nanoparticles into dermis and hypodermis.

Use of fractional laser microablation and ultrasound to facilitate the delivery of gold nanoparticles into skin in vivo

Science.gov (United States)

Terentyuk, G. S.; Genina, Elina A.; Bashkatov, A. N.; Ryzhova, M. V.; Tsyganova, N. A.; Chumakov, D. S.; Khlebtsov, B. N.; Sazonov, A. A.; Dolotov, L. E.; Tuchin, Valerii V.; Khlebtsov, Nikolai G.; Inozemtseva, O. A.

2012-06-01

The delivery of gold nanoparticles (nanocages coated with a layer of silicon dioxide (40/20 nm)) dispersed in the solution (glycerol + polyethylene glycol-400, 1 : 1) into the skin tissue is studied experimentally in vivo. From the data of optical coherence tomography and histochemical analysis it follows that simple application of suspension of nanoparticles is not efficient enough for delivery of the particles into the skin as a result of passive diffusion. It is shown that fractional laser microablation of skin before the application of the suspension, followed by the topical treatment by ultrasound allows penetration through the epidermis layer and delivery of nanoparticles into dermis and hypodermis

Retrospective analysis of the treatment of melasma lesions exhibiting increased vascularity with the 595-nm pulsed dye laser combined with the 1927-nm fractional low-powered diode laser.

Science.gov (United States)

Geddes, Elizabeth R C; Stout, Ashlyn B; Friedman, Paul M

2017-01-01

Melasma presents a significant challenge to laser surgeons. Aggressive treatments often result in rebound melasma or post-inflammatory pigmentary alteration. Recent reports suggest melasma pathogenesis may have a vascular component. Spectrocolorimetry can detect subtle or sub-clinical telangiectatic erythema within melasma lesions. For certain patients identified by spectrocolorimetry, effective melasma treatment may include vascular-targeted therapy together with pigment-specific treatment modalities. Such combined therapies may reduce the likelihood of melasma recurrence. To evaluate the efficacy of treating melasma lesions exhibiting subtle or sub-clinical telangiectatic erythema with the 595-nm pulsed dye laser (PDL) combined with the 1927-nm fractional low-powered diode laser (FDL). A retrospective review was performed over a 2-year period as follows. Evaluated patients (n = 11) include 10 women and 1 man, average age of 38.7 years, and Fitzpatrick skin types II-IV. Each patient exhibited melasma lesions with subtle or sub-clinical telangiectatic erythema identified by spectrocolorimetry. Each underwent a series of treatments (average of four) at approximate 4-6 week intervals of the PDL followed by the FDL. Treatments were performed same-day, sequentially, with 10-15 minute interim time allowance for skin cooling. The following PDL parameters were utilized: 10 mm spot, 10-20 ms pulse duration, 7.5-8.5 J/cm 2 fluence, 30/30 DCD. Eight passes with the FDL (Clear + Brilliant ® Permea™, Solta Medical, Hayward, CA) were then performed utilizing a "low" treatment level. Clinical endpoint was mild erythema and edema. Patients were encouraged to practice strict photoprotection and apply topical skin lightening agents, but compliance was not measured. An independent physician evaluated photographs taken at baseline and at follow-up after last treatment session (average follow-up of 96 days). A quartile improvement score was used to grade the

Treatment of burn scars in Fitzpatrick phototype III patients with a combination of pulsed dye laser and non-ablative fractional resurfacing 1550 nm erbium:glass/1927 nm thulium laser devices.

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Tao, Joy; Champlain, Amanda; Weddington, Charles; Moy, Lauren; Tung, Rebecca

2018-01-01

Burn scars cause cosmetic disfigurement and psychosocial distress. We present two Fitzpatrick phototype (FP) III patients with burn scars successfully treated with combination pulsed dye laser (PDL) and non-ablative fractional lasers (NAFL). A 30-year-old, FP III woman with a history of a second-degree burn injury to the bilateral arms and legs affecting 30% body surface area (BSA) presented for cosmetic treatment. The patient received three treatments with 595 nm PDL (7 mm, 8 J, 6 ms), six with the 1550 nm erbium:glass laser (30 mJ, 14% density, 4-8 passes) and five with the 1927 nm thulium laser (10 mJ, 30% density, 4-8 passes). Treated burn scars improved significantly in thickness, texture and colour. A 33-year-old, FP III man with a history of a second-degree burn injury of the left neck and arm affecting 7% BSA presented for cosmetic treatment. The patient received two treatments with 595 nm PDL (5 mm, 7.5 J, 6 ms), four with the 1550 nm erbium:glass laser (30 mJ, 14% density, 4-8 passes) and two with the 1927 nm thulium laser (10 mJ, 30% density, 4-8 passes). The burn scars became thinner, smoother and more normal in pigmentation and appearance. Our patients' burn scars were treated with a combination of PDL and NAFL (two wavelengths). The PDL targets scar hypervascularity, the 1550 nm erbium:glass stimulates collagen remodelling and the 1927 nm thulium targets epidermal processes, particularly hyperpigmentation. This combination addresses scar thickness, texture and colour with a low side effect profile and is particularly advantageous in patients at higher risk of post-procedure hyperpigmentation. Our cases suggest the combination of 595nm PDL plus NAFL 1550 nm erbium:glass/1927 nm thulium device is effective and well-tolerated for burn scar treatment in skin of colour.

Current Laser Resurfacing Technologies: A Review that Delves Beneath the Surface

Science.gov (United States)

Preissig, Jason; Hamilton, Kristy; Markus, Ramsey

2012-01-01

Numerous laser platforms exist that rejuvenate the skin by resurfacing its upper layers. In varying degrees, these lasers improve the appearance of lentigines and rhytides, eliminate photoaging, soften scarring due to acne and other causes, and treat dyspigmentation. Five major classes of dermatologic lasers are currently in common use: ablative and nonablative lasers in both fractionated and unfractionated forms as well as radiofrequency technologies. The gentler nonablative lasers allow for quicker healing, whereas harsher ablative lasers tend to be more effective. Fractionating either laser distributes the effect, increasing the number of treatments but minimizing downtime and complications. In this review article, the authors seek to inform surgeons about the current laser platforms available, clarify the differences between them, and thereby facilitate the identification of the most appropriate laser for their practice. PMID:23904818

In vivo non-invasive monitoring of collagen remodelling by two-photon microscopy after micro-ablative fractional laser resurfacing.

Science.gov (United States)

Cicchi, Riccardo; Kapsokalyvas, Dimitrios; Troiano, Michela; Campolmi, Piero; Morini, Cristiano; Massi, Daniela; Cannarozzo, Giovanni; Lotti, Torello; Pavone, Francesco Saverio

2014-11-01

Non-linear optical microscopy is becoming popular as a non-invasive in vivo imaging modality in dermatology. In this study, combined TPF and SHG microscopy were used to monitor collagen remodelling in vivo after micro-ablative fractional laser resurfacing. Papillary dermis of living subjects, covering a wide age range, was imaged immediately before and forty days after treatment. A qualitative visual examination of acquired images demonstrated an age-dependent remodelling effect on collagen. Additional quantitative analysis of new collagen production was performed by means of two image analysis methods. A higher increase in SHG to TPF ratio, corresponding to a stronger treatment effectiveness, was found in older subjects, whereas the effect was found to be negligible in young, and minimal in middle age subjects. Analysis of collagen images also showed a dependence of the treatment effectiveness with age but with controversial results. While the diagnostic potential of in vivo multiphoton microscopy has already been demonstrated for skin cancer and other skin diseases, here we first successfully explore its potential use for a non-invasive follow-up of a laser-based treatment. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Direct biological effects of fractional ultrapulsed CO2 laser irradiation on keratinocytes and fibroblasts in human organotypic full-thickness 3D skin models.

Science.gov (United States)

Schmitt, L; Huth, S; Amann, P M; Marquardt, Y; Heise, R; Fietkau, K; Huth, L; Steiner, T; Hölzle, F; Baron, J M

2018-05-01

Molecular effects of various ablative and non-ablative laser treatments on human skin cells-especially primary effects on epidermal keratinocytes and dermal fibroblasts-are not yet fully understood. We present the first study addressing molecular effects of fractional non-sequential ultrapulsed CO 2 laser treatment using a 3D skin model that allows standardized investigations of time-dependent molecular changes ex vivo. While histological examination was performed to assess morphological changes, we utilized gene expression profiling using microarray and qRT-PCR analyses to identify molecular effects of laser treatment. Irradiated models exhibited dose-dependent morphological changes resulting in an almost complete recovery of the epidermis 5 days after irradiation. On day 5 after laser injury with a laser fluence of 100 mJ/cm 2 , gene array analysis identified an upregulation of genes associated with tissue remodeling and wound healing (e.g., COL12A1 and FGF7), genes that are involved in the immune response (e.g., CXCL12 and CCL8) as well as members of the heat shock protein family (e.g., HSPB3). On the other hand, we detected a downregulation of matrix metalloproteinases (e.g., MMP3), differentiation markers (e.g., LOR and S100A7), and the pro-inflammatory cytokine IL1α.Overall, our findings substantiate the understanding of time-dependent molecular changes after CO 2 laser treatment. The utilized 3D skin model system proved to be a reliable, accurate, and reproducible tool to explore the effects of various laser settings both on skin morphology and gene expression during wound healing.

Measurements of void fraction in transparent two-phase flows by light extinction

International Nuclear Information System (INIS)

Shamoun, B.; El Beshbeeshy, M.; Bonazza, R.

1998-01-01

We report a technique for the measurement of the 2-D distribution of the line average void fraction in a two-phase flow with transparent gas and liquid components based on the Mie scattering induced by the gas bubbles on a collimated laser beam. The 2-D distribution of the line average of the interfacial area density is measured directly; the void fraction is deduced from it through an image processing algorithm. The technique is demonstrated with experiments in a pool of water injected with air and illuminated with a CW argon ion laser. (author)

The influence of laser pulse duration and energy on ICP-MS signal intensity, elemental fractionation, and particle size distribution in NIR fs-LA-ICP-MS

Science.gov (United States)

Diwakar, Prasoon K.; Harilal, Sivanandan S.; LaHaye, Nicole L.; Hassanein, Ahmed; Kulkarni, Pramod

2015-01-01

Laser parameters, typically wavelength, pulse width, irradiance, repetition rate, and pulse energy, are critical parameters which influence the laser ablation process and thereby influence the LA-ICP-MS signal. In recent times, femtosecond laser ablation has gained popularity owing to the reduction in fractionation related issues and improved analytical performance which can provide matrix-independent sampling. The advantage offered by fs-LA is due to shorter pulse duration of the laser as compared to the phonon relaxation time and heat diffusion time. Hence the thermal effects are minimized in fs-LA. Recently, fs-LA-ICP-MS demonstrated improved analytical performance as compared to ns-LA-ICP-MS, but detailed mechanisms and processes are still not clearly understood. Improvement of fs-LA-ICP-MS over ns-LA-ICP-MS elucidates the importance of laser pulse duration and related effects on the ablation process. In this study, we have investigated the influence of laser pulse width (40 fs to 0.3 ns) and energy on LA-ICP-MS signal intensity and repeatability using a brass sample. Experiments were performed in single spot ablation mode as well as rastering ablation mode to monitor the Cu/Zn ratio. The recorded ICP-MS signal was correlated with total particle counts generated during laser ablation as well as particle size distribution. Our results show the importance of pulse width effects in the fs regime that becomes more pronounced when moving from femtosecond to picosecond and nanosecond regimes. PMID:26664120

Effects of 1,540-nm Fractional Nonablative Erbium and 2,940-nm Fractional Ablative Erbium on p53 Epidermal Expression After 3 months: A Split-Face Interventional Study.

Science.gov (United States)

Borges, Juliano; Araújo, Luciana; de Oliveira, Rodrigo P B; Manela-Azulay, Monica

2018-04-16

Expression of p53 by keratinocytes may be important in the pathogenesis of skin cancer induced by ultraviolet light. We used side-by-side nonablative and ablative erbium fractional laser resurfacing to assess the effects on expression of p53 by facial keratinocytes. Ten female patients (age range, 50-63 years) with Fitzpatrick skin Types I-IV and clinical signs of photoaging underwent erbium fractional laser resurfacing (nonablative, 1,540-nm; ablative, 2,940-nm) on opposite sides of the face. Skin biopsies were obtained before treatment and 3 months after treatment for comparison with control biopsies of face and inner arm, quantifying p53 in immunostained tissue sections. Only ablative (2,940-nm) treatments produced a statistically significant reduction in p53 scoring after 3 months. The histologic appearance of skin after ablative resurfacing more closely resembled inner arm skin (rather than facial skin) of control subjects. Epidermal repopulation with p53-negative keratinocytes through ablative erbium fractional laser resurfacing may diminish the risk of eventual malignancy in photoaged skin.

UV and IR laser ablation for inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Smith, M.R.; Koppenaal, D.W.; Farmer, O.T.

1993-06-01

Laser ablation particle plume compositions are characterized using inductively coupled plasma mass spectrometry (ICP/MS). This study evaluates the mass response characteristics peculiar to ICP/MS detection as a function of laser fluence and frequency. Evaluation of the ICP/MS mass response allows deductions to be made concerning how representative the laser ablation produced particle plume composition is relative to the targeted sample. Using a black glass standard, elemental fractionation was observed, primarily for alkalis and other volatile elements. The extent of elemental fractionation between the target sample and the sampled plume varied significantly as a function of laser fluences and IR and UV laser frequency

Enhancement of light absorption by blood to Nd:YAG laser using PEG-modified gold nanorods.

Science.gov (United States)

Xing, Linzhuang; Li, Dong; Chen, Bin; Dai, Yuze; Wu, Wenjuan; Wang, Guoxiang

2016-10-01

On the basis of the principle of selective photothermolysis, laser therapy has been the most effective treatment strategy for Port-wine stains (PWSs) caused by the expansion of dermal capillaries. Neodymium:Yttrium Aluminum Garnet (Nd:YAG) laser at 1064 nm wavelength has great potential for deeply buried PWS, although its application is limited because of its weak absorption by blood. The purpose of this study is to investigate the effect of PEG-modified gold nanorods (NRs) on the blood absorption enhancement for Nd:YAG laser. PEG-modified gold nanorods (NRs) were synthesized via the seeded growth method. Then, the effect of PEG-modified gold NRs on blood light absorbance was investigated through adding different concentration of PEG-modified gold NRs to 1 ml of blood at room temperature. Finally, the optical properties of whole mice blood with or without PEG-modified gold NRs under slow heating were investigated. The average length and width of PEG-modified gold NRs are 79.5 ± 10.5 and 13.5 ± 0.9 nm, respectively, with the aspect ratio of 5.89, and a strong absorption peak exists at ∼1050 nm in the near-infrared range. A linear correlation between the blood absorbance at 1064 nm and the amount of PEG-modified gold NRs was obtained. The absorbance at 1064 nm increased 17.6, 33.0, 48.3, and 65.4 times when 0.4, 0.8, 1.2, and 1.6 mg of PEG-modified gold NRs was added to 1 ml of blood at room temperature, respectively. After adding 0.8 mg of PEG-modified gold NRs to 1 ml of blood, blood absorbance at 1064 nm at different temperatures increased by an average of 24.0 times. After intravenously injecting PEG-modified gold NRs (0.87 mg/ml) into Sprague-Dawley mice, the blood absorbance at 1064 nm increased from 0.014 to 0.5. Our findings suggest that PEG-modified gold NRs injection is an efficient way to enhance light absorption by blood to Nd:YAG laser. Lasers Surg. Med. 48:790-803, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley

Impact of laser power density on tribological properties of Pulsed Laser Deposited DLC films

Science.gov (United States)

Gayathri, S.; Kumar, N.; Krishnan, R.; AmirthaPandian, S.; Ravindran, T. R.; Dash, S.; Tyagi, A. K.; Sridharan, M.

2013-12-01

Fabrication of wear resistant and low friction carbon films on the engineered substrates is considered as a challenging task for expanding the applications of diamond-like carbon (DLC) films. In this paper, pulsed laser deposition (PLD) technique is used to deposit DLC films on two different types of technologically important class of substrates such as silicon and AISI 304 stainless steel. Laser power density is one of the important parameter used to tailor the fraction of sp2 bonded amorphous carbon (a-C) and tetrahedral amorphous carbon (ta-C) made by sp3 domain in the DLC film. The I(D)/I(G) ratio decreases with the increasing laser power density which is associated with decrease in fraction of a-C/ta-C ratio. The fraction of these chemical components is quantitatively analyzed by EELS which is well supported to the data obtained from the Raman spectroscopy. Tribological properties of the DLC are associated with chemical structure of the film. However, the super low value of friction coefficient 0.003 is obtained when the film is predominantly constituted by a-C and sp2 fraction which is embedded within the clusters of ta-C. Such a particular film with super low friction coefficient is measured while it was deposited on steel at low laser power density of 2 GW/cm2. The super low friction mechanism is explained by low sliding resistance of a-C/sp2 and ta-C clusters. Combination of excellent physical and mechanical properties of wear resistance and super low friction coefficient of DLC films is desirable for engineering applications. Moreover, the high friction coefficient of DLC films deposited at 9GW/cm2 is related to widening of the intergrain distance caused by transformation from sp2 to sp3 hybridized structure.

Anti-Neuroblastoma Activity of Gold Nanorods Bound with GD2 Monoclonal Antibody under Near-Infrared Laser Irradiation

International Nuclear Information System (INIS)

Peng, Ching-An; Wang, Chung-Hao

2011-01-01

High-risk neuroblastoma is one of the most common deaths in pediatric oncology. Current treatment of this disease involves a coordinated sequence of chemotherapy, surgery, and radiation. Further advances in therapy will require the targeting of tumor cells in a more selective and efficient way so that survival can be improved without substantially increasing toxicity. To achieve tumor-selective delivery, disialoganglioside (GD2) expressed by almost all neuroblastoma tumors represents a potential molecular target that can be exploited for tumor-selective delivery. In this study, GD2 monoclonal antibody (anti-GD2) was conjugated to gold nanorods (GNRs) which are one of anisotropic nanomaterials that can absorb near-infrared (NIR) laser light and convert it to energy for photothermolysis of tumor cells. Thiolated chitosan, due to its biocompatibility, was used to replace cetyltrimethylammonium bromide (CTAB) originally used in the synthesis of gold nanorods. In order to specifically target GD2 overexpressed on the surface of neuroblastoma stNB-V1 cells, anti-GD2 was conjugated to chitosan modified GNRs (CGNRs). To examine the fate of CGNRs conjugated with anti-GD2 after incubation with neuroblastoma cells, rhadoamine B was labeled on CGNRs functionalized with anti-GD2. Our results illustrated that anti-GD2-conjugated CGNRs were extensively endocytosed by GD2 + stNB-V1 neuroblastoma cells via antibody-mediated endocytosis. In addition, we showed that anti-GD2 bound CGNRs were not internalized by GD2 − SH-SY5Y neuroblastoma cells. After anti-GD2-linked CGNRs were incubated with neuroblatoma cells for six hours, the treated cells were further irradiated with 808 nm NIR laser. Post-NIR laser exposure, when examined by calcein-AM dye, stNB-V1 cells all underwent necrosis, while non-GD2 expressing SH-SY5Y cells all remained viable. Based on the in vitro study, CGNRs bound with anti-GD2 has the potential to be utilized as a therapeutic thermal coupling agent that generates

Safety and Efficacy of a 1550nm/1927nm Dual Wavelength Laser for the Treatment of Photodamaged Skin.

Science.gov (United States)

Narurkar, Vic A; Alster, Tina S; Bernstein, Eric F; Lin, Tina J; Loncaric, Anya

2018-01-01

BACKGROUND: Fractional photothermolysis (FP) is a popular treatment option for photodamaged skin and addresses shortcomings of ablative skin resurfacing and nonablative dermal remodeling. Previous studies have demonstrated that FP using the 1550nm wavelength has led to improvement of ultrastructural changes and clinical effects associated with photodamaged skin in the deeper dermal structures, while treatment with the 1927nm wavelength has shown clinical effects in the superficial dermis. Both wavelengths produce precise microscopic treatment zones (MTZs) in the skin. The two wavelengths used in combination may optimize the delivery of fractional nonablative resurfacing intended for dermal and epidermal coagulation of photodamage skin. OBJECTIVES: To evaluate the safety and efficacy of a 1550/1927 Laser System (Fraxel Dual, Solta), using both 1550nm and 1927nm wavelengths in combination for treatment of facial and non-facial photodamage. METHODS: Prospective, multi-center, post-market study in subjects with clinically identifiable photodamage (N=35) (Fitzpatrick skin types I-IV). Both 1550nm and 1927nm wavelengths were used at each treatment visit. Investigator assessment of the affected area(s) occurred at one week, one month and 3 months after a series of up to four treatments. Severity of adverse events (AEs) were assessed using a 4-point scale (where 0=none and 3=marked). Assessments included erythema, edema, hyperkeratosis, hyper- and hypo-pigmentation, scarring, itchiness, dryness, and flaking. Severity of photoaging, fine and coarse wrinkling, mottled hyperpigmentation, sallowness, and tactile roughness at baseline was assessed using the same scale. Investigators and subjects assessed overall appearance of photodamage and pigmentation based on a 5-point quartile improvement scale at all follow-up visits (where 0=no improvement and 4=very significant improvement [76%-100%]). RESULTS: There was a positive treatment effect at all study visits, with moderate

Tunable fractional-order Fourier transformer

International Nuclear Information System (INIS)

Malyutin, A A

2006-01-01

A fractional two-dimensional Fourier transformer whose orders are tuned by means of optical quadrupoles is described. It is shown that in the optical scheme considered, the Fourier-transform order a element of [0,1] in one of the mutually orthogonal planes corresponds to the transform order (2-a) in another plane, i.e., to inversion and inverse Fourier transform of the order a. (laser modes and beams)

Fractional dynamics of charged particles in magnetic fields

Science.gov (United States)

Coronel-Escamilla, A.; Gómez-Aguilar, J. F.; Alvarado-Méndez, E.; Guerrero-Ramírez, G. V.; Escobar-Jiménez, R. F.

2016-02-01

In many physical applications the electrons play a relevant role. For example, when a beam of electrons accelerated to relativistic velocities is used as an active medium to generate Free Electron Lasers (FEL), the electrons are bound to atoms, but move freely in a magnetic field. The relaxation time, longitudinal effects and transverse variations of the optical field are parameters that play an important role in the efficiency of this laser. The electron dynamics in a magnetic field is a means of radiation source for coupling to the electric field. The transverse motion of the electrons leads to either gain or loss energy from or to the field, depending on the position of the particle regarding the phase of the external radiation field. Due to the importance to know with great certainty the displacement of charged particles in a magnetic field, in this work we study the fractional dynamics of charged particles in magnetic fields. Newton’s second law is considered and the order of the fractional differential equation is (0;1]. Based on the Grünwald-Letnikov (GL) definition, the discretization of fractional differential equations is reported to get numerical simulations. Comparison between the numerical solutions obtained on Euler’s numerical method for the classical case and the GL definition in the fractional approach proves the good performance of the numerical scheme applied. Three application examples are shown: constant magnetic field, ramp magnetic field and harmonic magnetic field. In the first example the results obtained show bistability. Dissipative effects are observed in the system and the standard dynamic is recovered when the order of the fractional derivative is 1.

Propagation of optical vortices with fractional topological charge in free space

Science.gov (United States)

Ali, Tamelia; Kreminska, Liubov; Golovin, Andrii B.; Crouse, David T.

2014-10-01

The behavior of the optical vortices with fractional topological charges in the far-field is assessed through numerical modeling and confirmed by experimental results. The generation of fractional topological charge variations of the phase within a Gaussian beam was achieved by using a liquid crystal spatial light modulator (LCoS SLM). It is shown that a laser beam carrying an optical vortex with a fractional topological charge evolves into a beam with a topological charge of integer value, specifically an integer value closer to the fractional number in the far field. A potential application of this work is for data transmission within optical telecommunication systems.

New lasers and light sources - old and new risks?

DEFF Research Database (Denmark)

Paasch, Uwe; Schwandt, Antje; Seeber, Nikolaus

2017-01-01

Recent developments (new wavelengths, treatment concepts, and combinations) in the field of lasers, intense pulsed light (IPL), LED, as well as new energy and light sources have opened up new therapeutic options that extend beyond mere aesthetic indications. Thus, while fractional lasers used...

Laser-assisted deposition of thin C60 films

DEFF Research Database (Denmark)

Schou, Jørgen; Canulescu, Stela; Fæster, Søren

Metal and metal oxide films with controlled thickness from a fraction of a monolayer up more than 1000 nm and known stoichiometry can be produced by pulsed laser deposition (PLD) relatively easily, and (PLD) is now a standard technique in all major research laboratories within materials science...... of the matrix material, anisole, with a concentration of 0.67 wt% C60. At laser fluences below 1.5 J/cm2, a dominant fraction of the film molecules are C60 transferred to the substrate without any fragmentation. High-resolution SEM images of MAPLE deposited films reveal large circular features on the surface...

Kinetics and tissue repair process following fractional bipolar radiofrequency treatment.

Science.gov (United States)

Kokolakis, G; von Eichel, L; Ulrich, M; Lademann, J; Zuberbier, T; Hofmann, M A

2018-05-15

Fractionated radiofrequency (RF) tissue tightening is an alternative method to fractionated laser treatment of skin wrinkling, laxity and acne scars, with reduced risk of scarring or persistent pigmentation. The aim of this study was to evaluate and quantify the wound healing process after RF treatment. 12 patients were treated with a 64-pin fractional bipolar RF device with 60 mJ/pin applied energy. Confocal laser scanning microscopy (CLSM) examination was performed on day 1, day 2, day 7 and day 14 after treatment. Clinical wound healing process was measured and expressed as a percentage. All patients developed erythema, mild edema and crusts at the treated areas. Two weeks after treatment clinical symptoms resolved. During ablation patients reported moderate pain. Directly after ablation microscopic ablation zones could be detected in CLSM. Measurement of MAZ at epidermis, dermo-epidermal junction and papilary dermis showed a constant diameter until two weeks after treatment. Re-epithelization of the MAZ could be detected already 1 week after treatment. However, 2 weeks after ablation the honeycomb pattern of the epidermis was not yet completely restored. Bipolar fractionated RF treatment demonstrates clinically a rapid wound healing response. The subepidermal remodelling process still ongoing after 14 days, showing new granulation tissue. Therefore, treatment intervals of at least 14 days should be recommended to allow completion of the remodelling process.

The onset of coherence collapse in DBR lasers

International Nuclear Information System (INIS)

Woodward, S.L.; Koch, T.L.; Koren, U.

1990-01-01

The authors investigate how the onset of coherence collapse depends on laser output power. The lasers were three-section multiquantum-well distributed-Bragg-reflector (MQW-DBR) lasers. The fraction of light reflected back into the lasing mode was varied, and the point at which the transition to coherence collapse occurred was measured. This feedback level varies approximately linearly with laser output power. For these lasers, when the output power is 1 mW, the transition to coherence collapse beings when the optical feedback into the lasing mode is below - 40 dBm; when the feedback power is - 35 dBm the laser line is completely collapsed

A compact, robust, and transportable ultra-stable laser with a fractional frequency instability of 1 × 10{sup −15}

Energy Technology Data Exchange (ETDEWEB)

Chen, Qun-Feng; Nevsky, Alexander; Cardace, Marco; Schiller, Stephan, E-mail: Step.Schiller@uni-duesseldorf.de [Institut für Experimentalphysik, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf (Germany); Legero, Thomas; Häfner, Sebastian; Uhde, Andre; Sterr, Uwe [Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig (Germany)

2014-11-15

We present a compact and robust transportable ultra-stable laser system with minimum fractional frequency instability of 1 × 10{sup −15} at integration times between 1 and 10 s. The system was conceived as a prototype of a subsystem of a microwave-optical local oscillator to be used on the satellite mission Space-Time Explorer and QUantum Equivalence Principle Space Test (STE-QUEST) ( http://sci.esa.int/ste-quest/ ). It was therefore designed to be compact, to sustain accelerations occurring during rocket launch, to exhibit low vibration sensitivity, and to reach a low frequency instability. Overall dimensions of the optical system are 40 cm × 20 cm × 30 cm. The acceleration sensitivities of the optical frequency in the three directions were measured to be 1.7 × 10{sup −11}/g, 8.0 × 10{sup −11}/g, and 3.9 × 10{sup −10}/g, and the absolute frequency instability was determined via a three-cornered hat measurement. Two additional cavity-stabilized lasers were used for this purpose, one of which had an instability σ{sub y} < 4 × 10{sup −16} at 1 s integration time. The design is also appropriate and useful for terrestrial applications.

Soil Particle Size Analysis by Laser Diffractometry: Result Comparison with Pipette Method

Science.gov (United States)

Šinkovičová, Miroslava; Igaz, Dušan; Kondrlová, Elena; Jarošová, Miriam

2017-10-01

Soil texture as the basic soil physical property provides a basic information on the soil grain size distribution as well as grain size fraction representation. Currently, there are several methods of particle dimension measurement available that are based on different physical principles. Pipette method based on the different sedimentation velocity of particles with different diameter is considered to be one of the standard methods of individual grain size fraction distribution determination. Following the technical advancement, optical methods such as laser diffraction can be also used nowadays for grain size distribution determination in the soil. According to the literature review of domestic as well as international sources related to this topic, it is obvious that the results obtained by laser diffractometry do not correspond with the results obtained by pipette method. The main aim of this paper was to analyse 132 samples of medium fine soil, taken from the Nitra River catchment in Slovakia, from depths of 15-20 cm and 40-45 cm, respectively, using laser analysers: ANALYSETTE 22 MicroTec plus (Fritsch GmbH) and Mastersizer 2000 (Malvern Instruments Ltd). The results obtained by laser diffractometry were compared with pipette method and the regression relationships using linear, exponential, power and polynomial trend were derived. Regressions with the three highest regression coefficients (R2) were further investigated. The fit with the highest tightness was observed for the polynomial regression. In view of the results obtained, we recommend using the estimate of the representation of the clay fraction (analysis is done according to laser diffractometry. The advantages of laser diffraction method comprise the short analysis time, usage of small sample amount, application for the various grain size fraction and soil type classification systems, and a wide range of determined fractions. Therefore, it is necessary to focus on this issue further to address the

Combined fractional resurfacing (10600 nm/1540 nm): Tridimensional imaging evaluation of a new device for skin rejuvenation.

Science.gov (United States)

Mezzana, Paolo; Valeriani, Maurizio; Valeriani, Roberto

2016-11-01

In this study were described the results, by tridimensional imaging evaluation, of the new "Combined Fractional Resurfacing" technique with the first fractional laser that overtakes the limits of traditional ablative, nonablative fractional resurfacing by combining CO 2 ablative and GaAs nonablative lasers. These two wavelengths can work separately or in a mixed modality to give the best treatment choice to all the patients. In this study, it is demonstrated that the simultaneous combination of the CO 2 wavelength (10600 nm) and GaAs wavelength (1540 nm) reduced the downtime, reduced pain during the treatment, and produced better results on fine wrinkles reduction and almost the same results on pigmentation as seen with 3D analysis by Antera (Miravex).

New lasers and light sources - old and new risks?

DEFF Research Database (Denmark)

Paasch, Uwe; Schwandt, Antje; Seeber, Nikolaus

2017-01-01

Recent developments (new wavelengths, treatment concepts, and combinations) in the field of lasers, intense pulsed light (IPL), LED, as well as new energy and light sources have opened up new therapeutic options that extend beyond mere aesthetic indications. Thus, while fractional lasers used to ...

An update on the use of laser technology in skin vaccination

Science.gov (United States)

Chen, Xinyuan; Wang, Ji; Shah, Dilip; Wu, Mei X

2014-01-01

Vaccination via skin often induces stronger immune responses than via muscle. This, in line with potential needle-free, painless delivery, makes skin a very attractive site for immunization. Yet, despite decades of effort, effective skin delivery is still in its infant stage and safe and potent adjuvants for skin vaccination remain largely undefined. We have shown that laser technologies including both fractional and non-fractional lasers can greatly augment vaccine-induced immune response without incurring any significant local and systemic side effects. Laser illumination at specific settings can accelerate the motility of antigen-presenting cells or trigger release of ‘danger’ signals stimulating the immune system. Moreover, several other groups including the authors explore laser technologies for needle-free transcutaneous vaccine delivery. As these laser-mediated resurfacing technologies are convenient, safe and cost-effective, their new applications in vaccination warrant clinical studies in the very near future. PMID:24127871

In vivo multiphoton-microscopy of picosecond-laser-induced optical breakdown in human skin.

Science.gov (United States)

Balu, Mihaela; Lentsch, Griffin; Korta, Dorota Z; König, Karsten; Kelly, Kristen M; Tromberg, Bruce J; Zachary, Christopher B

2017-08-01

Improvements in skin appearance resulting from treatment with fractionated picosecond-lasers have been noted, but optimizing the treatment efficacy depends on a thorough understanding of the specific skin response. The development of non-invasive laser imaging techniques in conjunction with laser therapy can potentially provide feedback for guidance and optimizing clinical outcome. The purpose of this study was to demonstrate the capability of multiphoton microscopy (MPM), a high-resolution, label-free imaging technique, to characterize in vivo the skin response to a fractionated non-ablative picosecond-laser treatment. Two areas on the arm of a volunteer were treated with a fractionated picosecond laser at the Dermatology Clinic, UC Irvine. The skin response to treatment was imaged in vivo with a clinical MPM-based tomograph at 3 hours and 24 hours after treatment and seven additional time points over a 4-week period. MPM revealed micro-injuries present in the epidermis. Pigmented cells were particularly damaged in the process, suggesting that melanin is likely the main absorber for laser induced optical breakdown. Damaged individual cells were distinguished as early as 3 hours post pico-laser treatment with the 532 nm wavelength, and 24 hours post-treatment with both 532 and 1064 nm wavelengths. At later time points, clusters of cellular necrotic debris were imaged across the treated epidermis. After 24 hours of treatment, inflammatory cells were imaged in the proximity of epidermal micro-injuries. The epidermal injuries were exfoliated over a 4-week period. This observational and descriptive pilot study demonstrates that in vivo MPM imaging can be used non-invasively to provide label-free contrast for describing changes in human skin following a fractionated non-ablative laser treatment. The results presented in this study represent the groundwork for future longitudinal investigations on an expanded number of subjects to understand the response to treatment

Ablative fractional carbon dioxide laser combined with intense pulsed light for the treatment of photoaging skin in Chinese population: A split-face study.

Science.gov (United States)

Mei, Xue-Ling; Wang, Li

2018-01-01

Intense pulsed light (IPL) is effective for the treatment of lentigines, telangiectasia, and generalized erythema, but is less effective in the removal of skin wrinkles. Fractional laser is effective on skin wrinkles and textural irregularities, but can induce postinflammatory hyperpigmentation (PIH), especially in Asians. This study evaluated the safety and efficacy of ablative fractional laser (AFL) in combination with IPL in the treatment of photoaging skin in Asians.This study included 28 Chinese women with Fitzpatrick skin type III and IV. The side of the face to be treated with IPL alone (3 times) or AFL in combination with IPL (2 IPL treatments and 1 AFL treatment) was randomly selected. Skin conditions including hydration, transepidermal water loss, elasticity, spots, ultraviolet spots, brown spots, wrinkle, texture, pore size and red areas, as well as adverse effects were evaluated before the treatment and at 30 days after the treatment.Compared with IPL treatment alone, AFL in combination with IPL significantly increased elasticity, decreased pore size, reduced skin wrinkles, and improved skin texture (P = .004, P = .039, P = .015, and P = .035, respectively). Both treatment protocols produced similar effects in relation to the improvement of photoaging-induced pigmentation. The combined therapy did not impair epidermal barrier function. No postoperative infection, hypopigmentation, or scarring occurred after IPL and AFL treatments. PIH occurred at 1 month after AFL treatment and disappeared at 30 days after completion of the combined therapy.AFL in combination with IPL is safe and effective for photoaging skin in Asians. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

Fractional high-harmonic combs by attosecond-precision split-spectrum pulse control

Directory of Open Access Journals (Sweden)

Laux Martin

2013-03-01

Full Text Available Few-cycle laser fields enable pulse-shaping control of high-order harmonic generation by time delaying variable broadband spectral sections. We report the experimental generation of fractional (noninteger high-harmonic combs by the controlled interference of two attosecond pulse trains. Additionally the energy of the high harmonics is strongly tuned with the relative time delay. We quantify the tuning to directly result from the controlled variation of the instantaneous laser frequency at the shaped driver pulse intensity maximum.

The Mercury Laser Advances Laser Technology for Power Generation

Energy Technology Data Exchange (ETDEWEB)

Ebbers, C A; Caird, J; Moses, E

2009-01-21

The National Ignition Facility (NIF) at Lawrence Livermore Laboratory is on target to demonstrate 'breakeven' - creating as much fusion-energy output as laser-energy input. NIF will compress a tiny sphere of hydrogen isotopes with 1.8 MJ of laser light in a 20-ns pulse, packing the isotopes so tightly that they fuse together, producing helium nuclei and releasing energy in the form of energetic particles. The achievement of breakeven will culminate an enormous effort by thousands of scientists and engineers, not only at Livermore but around the world, during the past several decades. But what about the day after NIF achieves breakeven? NIF is a world-class engineering research facility, but if laser fusion is ever to generate power for civilian consumption, the laser will have to deliver pulses nearly 100,000 times faster than NIF - a rate of perhaps 10 shots per second as opposed to NIF's several shots a day. The Mercury laser (named after the Roman messenger god) is intended to lead the way to a 10-shots-per-second, electrically-efficient, driver laser for commercial laser fusion. While the Mercury laser will generate only a small fraction of the peak power of NIF (1/30,000), Mercury operates at higher average power. The design of Mercury takes full advantage of the technology advances manifest in its behemoth cousin (Table 1). One significant difference is that, unlike the flashlamp-pumped NIF, Mercury is pumped by highly efficient laser diodes. Mercury is a prototype laser capable of scaling in aperture and energy to a NIF-like beamline, with greater electrical efficiency, while still running at a repetition rate 100,000 times greater.

Planar measurements of soot volume fraction and OH in a JP-8 pool fire

Energy Technology Data Exchange (ETDEWEB)

Henriksen, Tara L.; Ring, Terry A.; Eddings, Eric G. [Department of Chemical Engineering, University of Utah, Salt Lake City, UT 84112 (United States); Nathan, Graham J. [School of Mechanical Engineering, University of Adelaide, SA 5005 (Australia); Alwahabi, Zeyad T.; Qamar, Nader [School of Chemical Engineering, University of Adelaide, SA 5005 (Australia)

2009-07-15

The simultaneous measurement of soot volume fraction by laser induced incandescence (LII) and qualitative imaging of OH by laser induced fluorescence (LIF) was performed in a JP-8 pool fire contained in a 152 mm diameter pan. Line of sight extinction was used to calibrate the LII system in a laminar flame, and to provide an independent method of measuring average soot volume fraction in the turbulent flame. The presence of soot in the turbulent flame was found to be approximately 50% probable, resulting in high levels of optical extinction, which increased slightly through the flame from approximately 30% near the base, to approximately 50% at the tip. This high soot loading pushes both techniques toward their detection limit. Nevertheless, useful accuracy was obtained, with the LII measurement of apparent extinction in the turbulent flame being approximately 21% lower than a direct measurement, consistent with the influence of signal trapping. The axial and radial distributions of soot volume fraction are presented, along with PDFs of volume fraction, and new insight into the behavior of soot sheets in pool fires are sought from the simultaneous measurements of OH and LII. (author)

Laser applications in nuclear physics

International Nuclear Information System (INIS)

Murnick, D.E.

1985-01-01

A large fraction of the International Workshop on Hyperfine Interactions was devoted to various aspects of 'laser applications in nuclear physics'. This panel discussion took place before all of the relevant formal presentations on the subject were complete. Nevertheless, there had been sufficient discussions for the significance of this emerging area of hyperfine interaction research to be made clear. An attempt was made to identify critical and controversial aspects of the subject in order to critically evaluate past successes and indicate important future directions of research. Each of the panelists made a short statement on one phase of laser-nuclear physics research, which was followed by general discussions with the other panelists and the audience. In this report, a few areas which were not covered in the formal presentations are summarized: extensions of laser spectroscopy to shorter lifetimes; extension of laser techniques to nuclei far off stability; interpretation of laser spectroscopic data; sensitivity and spectral resolution; polarized beams and targets. (Auth.)

Nonablative Fractional Laser Resurfacing in Skin of Color: Evidence-based Review

OpenAIRE

Kaushik, Shivani B.; Alexis, Andrew F.

2017-01-01

Background: Nonablative laser resurfacing represents one of the major advances in procedural dermatology over the past decade. However, its use in darker skin types is limited by safety concerns and a relative lack of available data.

Bistable laser device with multiple coupled active vertical-cavity resonators

Science.gov (United States)

Fischer, Arthur J.; Choquette, Kent D.; Chow, Weng W.

2003-08-19

A new class of bistable coupled-resonator vertical-cavity semiconductor laser devices has been developed. These bistable laser devices can be switched, either electrically or optically, between lasing and non-lasing states. A switching signal with a power of a fraction of a milliwatt can change the laser output of such a device by a factor of a hundred, thereby enabling a range of optical switching and data encoding applications.

Laser ablation in analytical chemistry - A review

Energy Technology Data Exchange (ETDEWEB)

Russo, Richard E.; Mao, Xianglei; Liu, Haichen; Gonzalez, Jhanis; Mao, Samuel S.

2001-10-10

Laser ablation is becoming a dominant technology for direct solid sampling in analytical chemistry. Laser ablation refers to the process in which an intense burst of energy delivered by a short laser pulse is used to sample (remove a portion of) a material. The advantages of laser ablation chemical analysis include direct characterization of solids, no chemical procedures for dissolution, reduced risk of contamination or sample loss, analysis of very small samples not separable for solution analysis, and determination of spatial distributions of elemental composition. This review describes recent research to understand and utilize laser ablation for direct solid sampling, with emphasis on sample introduction to an inductively coupled plasma (ICP). Current research related to contemporary experimental systems, calibration and optimization, and fractionation is discussed, with a summary of applications in several areas.

The KMSF laser fusion programme

International Nuclear Information System (INIS)

Berger, R.L.; Campbell, P.M.; Charatis, G.

1979-01-01

Laser-driven implosion experiments have been performed at both 1.06μm and 0.53μm. The fractional absorption was greater at 0.53μm although with the laser power available at 0.53μm it was not possible to observe effects of a high-temperature corona. Other experiments were performed using cryogenic targets at 1.06μm. It was found that the neutron yield and peak fuel densities were greater when the fuel formed a liquid or solid layer on the inside of the spherical glass-shell targets. (author)

Evaluation of microneedling fractional radiofrequency device for treatment of acne scars

Directory of Open Access Journals (Sweden)

Byalekere Shivanna Chandrashekar

2014-01-01

Full Text Available Background: Various treatment modalities including non-invasive methods such as chemical peels, topical retinoids, microdermabrasion, minimally invasive techniques such as microneedling, fractional lasers, microneedling radiofrequency devices and invasive procedures such as acne scar surgeries and ablative lasers are used for acne scars, each with its own unique advantages and disadvantages. This study is a retrospective assessment of efficacy and safety of microneedling fractional radiofrequency in the treatment of acne scars. Methods: Thirty one patients of skin types III-V with moderate and severe facial acne scarring received four sequential fractional radiofrequency treatments over a period of 6 months with an interval of 6 weeks between each session. Goodman & Baron′s acne scar grading system was used for assessment by a side by side comparison of preoperative and post- operative photographs taken at their first visit and at the end of 3 months after the last session. Results: Estimation of improvement with Goodman and Baron′s Global Acne Scarring System showed that by qualitative assessment of 31 patients with grade 3 and grade 4 acne scars, 80.64% showed improvement by 2 grades and 19.35% showed improvement by 1 grade. Quantitative assessment showed that 58% of the patients had moderate, 29% had minimal, 9% had good and 3% showed very good improvement. Adverse effects were limited to transient pain, erythema, edema and hyperpigmentation. Conclusion: Microneedling fractional radiofrequency is efficacious for the treatment of moderate and severe acne scars.

Calorimeters for diagnosis of laser-fusion experiments

International Nuclear Information System (INIS)

Gunn, S.R.

1976-01-01

A variety of calorimeters have been developed for measuring ions, x-rays, and scattered radiation emanating from laser-pulse-imploded fusion targets. The ion and x-ray calorimeters use metal or glass absorbers to reflect or transmit most of the scattered laser radiation; the versions using metal absorbers also incorporate a differential construction to compensate for the fraction of the scattered laser radiation that is absorbed. The scattered-radiation calorimeters use colored glass to absorb the radiation and a transparent glass shield to remove ions and x rays. Most of the calorimeters use commercial semiconductor thermoelectric modules as the temperature sensors

Influence of laser-supported detonation waves on metal drilling with pulsed CO2 lasers

International Nuclear Information System (INIS)

Stuermer, E.; von Allmen, M.

1978-01-01

Drilling of highly reflective metals in an ambient atmosphere with single TEA-CO 2 -laser pulses of fluences between 300 and 6000 J/cm 2 is reported. The drilling process was investigated by measuring the time-resolved laser power reflected specularly from the targets during the interaction and by analyzing the craters produced. Experiments were performed in ambient air, argon, and helium. Target damage was found to be strongly influenced by a laser-supported detonation (LSD) wave in the ambient gas. If the laser fluence exceeded a material-dependent damage threshold (copper: 300 J/cm 2 ), drilling occurred, but the efficiency was inversely related to the duration of the LSD wave. Efficient material removal is possible if the LSD wave can be dissipated within a small fraction of the laser pulse duration. This was achieved by small-F-number focusing of TEM 00 laser pulses of 5-μs duration. Replacing the ambient air at the target by a gas of lower density results in a further significant reduction of LSD-wave lifetime, and a correlated increase of the drilling yield. On copper targets a maximum drilling yield of 10 -5 cm 3 /J was observed in ambient helium at a laser fluence of 1 kJ/cm 2

Tensile behavior of laser treated Fe-Si-B metallic glass

Energy Technology Data Exchange (ETDEWEB)

Joshi, Sameehan S.; Samimi, Peyman; Ghamarian, Iman; Katakam, Shravana; Collins, Peter C.; Dahotre, Narendra B., E-mail: narendra.dahotre@unt.edu [Department of Materials Science and Engineering, University of North Texas, 1150 Union Circle 305310, Denton, Texas 76203-5017 (United States)

2015-10-28

Fe-Si-B metallic glass foils were treated with a linear laser track using a continuous wave Nd-YAG laser and its effect on the overall tensile behavior was investigated. Microstructure and phase evolutions were evaluated using X-ray diffraction, resistivity measurements, and transmission electron microscopy. Crystallization fraction was estimated via the differential scanning calorimetry technique. Metallic glass foils treated with the lower laser fluences (<0.49 J/mm{sup 2}) experienced structural relaxation, whereas higher laser fluences led to crystallization within the laser treated region. The overall tensile behavior was least impacted by structural relaxation, whereas crystallization severely reduced the ultimate tensile strength of the laser treated metallic glass foils.

Lorentz laser-assisted stripping (Lolas) for H-/H0 injection into proton drivers

International Nuclear Information System (INIS)

Gastaldi, Ugo

2002-01-01

We discuss the main components of schemes for Lorentz laser-assisted stripping (abbreviated Lolas henceforth) proposed for injection into proton driver accumulators: H- → H0 + e- Lorentz stripping, H0→H0(n) laser excitation, H0(n)→p+ + e- Lorentz stripping. We mention results obtained in practice of H- beam transport and storage and of experiments addressing physics of the H- ion, of the H0 atom and of vacuum, which prove the feasibility of each Lolas component. For high enough injection energies, it is feasible to split without losses the H0 beam sent towards the accumulator into a fraction stripped to p+s and stored inside the accumulator and a complementary fraction of H0s delivered to high duty-cycle users. The fraction of stored beam can exceed 50% with one single Fabry-Perot cavity used to enhance the laser power density. Aspects of Lolas integration and optimization are pointed out

Sliding wear resistance of metal matrix composite layers prepared by high power laser

NARCIS (Netherlands)

Ocelik, Vaclav; Matthews, D; de Hosson, Jeff

2005-01-01

Two laser surface engineering techniques, Laser Cladding and Laser Melt Injection (LMI), were used to prepare three different metal matrix composite layers with a thickness of about 1 mm and approximately 25-30% volume fraction of ceramic particles. SiC/Al-8Si, WC/Ti-6Al-4V and TiB2/Ti-6Al-4V layers

Treatment of acne scars and wrinkles in asian patients using carbon-dioxide fractional laser resurfacing: its effects on skin biophysical profiles.

Science.gov (United States)

Hwang, Young Ji; Lee, Yu Na; Lee, Yang Won; Choe, Yong Beom; Ahn, Kyu Joong

2013-11-01

Although ablative fractional resurfacing is known to be effective against photoaging and acne scars, studies on its efficacy, safety and changes in the skin characteristics of Asians are limited. The aim of this study is to assess the efficacy and safety of carbon dioxide fractional laser (CO2FL) in Koreans treated for wrinkles and acne scars, and to define the changes in skin characteristics during recovery period. We administered one session of CO2FL on 10 acne scar patients and 14 wrinkles patients with skin types IV and V. The surveillance of efficacy and side effects along with the measurement of biophysical properties was carried out before 1 day, 1 week, 1 month and 3 months after treatment. Using a non-invasive method, skin barrier damage, erythema and bronzing of skin during the recovery period were assessed, and all of the items eventually returned to the pre-treatment level. Skin elasticity was measured in the wrinkle group, and the statistically significant effect was sustained throughout the next three months. The outcome of treatment was found to be better than 'moderate improvement' in both the acne scar and wrinkle groups. Further, there were no serious side effects three months post-procedure. CO2 FL is thought to be an effective and safe method for treating moderate to severe acne scars and wrinkles in Asians.

Protein fraction heterogeneity in donkey’s milk analysed by proteomic methods

Directory of Open Access Journals (Sweden)

G. D'Urso

2010-04-01

Full Text Available Donkey’s milk is often well tolerate by patients affected by cow’s milk protein allergy, probably thanks to its protein composition. This empiric evidence, confirmed by some clinical trials, needs to be better investigated. A preliminary survey on the protein fraction of donkey’s milk was carried out: fifty-six individual milk samples have been collected and analysed by IEF and SDS-PAGE. Five different IEF patterns have been identified, showing a marked heterogeneity both in casein and whey protein fractions. A single IEF pattern showed an apparent reduced amount of casein fraction highlighted by SDS. Three of the five IEF patterns have been further investigated by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS.

Blue-green ZnSe lasers with a new type of active region

International Nuclear Information System (INIS)

Ivanov, S.V.; Toropov, A.A.; Sorokin, S.V.; Shubina, T.V.; Sedova, I.V.; Kop'ev, P.S.; Alferov, Zh.I.; Waag, A.; Lugauer, H.J.; Reuscher, G.; Keim, M.; Fischer, F.F.; Landwehr, G.

1999-01-01

We report the results of an experimental study of molecular-beam epitaxy of ZnSe-based laser heterostructures with a new structure of the active region, which contains a fractional-monolayer CdSe recombination region in an expanded ZnSe quantum well and a waveguide based on a variably-strained, short-period superlattice are reported. Growth of a fractional-monolayer CdSe region with a nominal thickness of 2-3 ML, i.e., less than the critical thickness, on a ZnSe surface (Δa/a∼7%) leads to the formation of self-organized, pseudomorphic, CdSe-enriched islands with lateral dimensions ∼10-30 nm and density ∼2x10 10 cm -2 , which serve as efficient centers of carrier localization, giving rise to effective spatial separation of defective regions and regions of radiative recombination and, as a result, a higher quantum efficiency. Laser structures for optical pumping in the (Zn, Mg) (S, Se) system with a record-low threshold power density (less than 4 kW/cm 2 at 300 K) and continuous-wave laser diodes in the system (Be, Mg, Zn) Se with a 2.5 to 2.8-ML-thick, fractional-monolayer CdSe active region have been obtained. The laser structures and diodes have an improved degradation resistance

Study of plasma parameters influencing fractionation in laser ablation-inductively coupled plasma-mass spectrometry

Science.gov (United States)

Gäckle, M.; Merten, D.

2010-12-01

Methods permitting to test the influence of the matrix as well as of its local and temporal distribution on the plasma conditions in laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) are developed. For this purpose, the MS interface is used as plasma probe allowing to investigate the average plasma condition within the ICP zone observed in terms of temporal and spatial distribution of the matrix. Inserted matrix particles, particularly when being atomized and ionized, can cause considerable changes in both electron density and plasma temperature thus influencing the ionization equilibrium of the individual analytes. In this context, the plasma probe covers a region of the plasma for which no local thermodynamic equilibrium can be assumed. The differences in temperature, identified within the region of the plasma observed, amounted up to 3000 K. While in the central region conditions were detected that would not allow efficient atomization and ionization of the matrix, these conditions improve considerably towards the margin of the area observed. Depending on the nature as well as on the temporally and locally variable density of the matrix, this can lead to varying intensity ratios of the analytes and explain fractionation effects. By means of a derived equation it is shown that the deviation of the intensity ratio from the concentration ratio turns out to be more serious the higher the difference of the ionization potential of the analytes observed, the lower the plasma temperature and the higher the matrix concentration within the area observed.

Energy of a shock wave generated in different metals under irradiation by a high-power laser pulse

International Nuclear Information System (INIS)

Gus'kov, S. Yu.; Kasperczuk, A.; Pisarczyk, T.; Borodziuk, S.; Ullschmied, J.; Krousky, E.; Masek, K.; Pfeifer, M.; Skala, J.; Pisarczyk, P.

2007-01-01

The energies of a shock wave generated in different metals under irradiation by a high-power laser beam were determined experimentally. The experiments were performed with the use of targets prepared from a number of metals, such as aluminum, copper, silver and lead (which belong to different periods of the periodic table) under irradiation by pulses of the first and third harmonics of the PALS iodine laser at a radiation intensity of approximately 10 14 W/cm 2 . It was found that, for heavy metals, like for light solid materials, the fraction of laser radiation energy converted into the energy of a shock wave under irradiation by a laser pulse of the third harmonic considerably (by a factor of 2-3) exceeds the fraction of laser radiation energy converted under irradiation by a laser pulse of the first harmonic. The influence of radiation processes on the efficiency of conversion of the laser energy into the energy of the shock wave was analyzed

Bell nonlocality and fully entangled fraction measured in an entanglement-swapping device without quantum state tomography

Czech Academy of Sciences Publication Activity Database

Bartkiewicz, K.; Lemr, K.; Černoch, Antonín; Miranowicz, A.

2017-01-01

Roč. 95, č. 3 (2017), s. 1-7, č. článku 030102. ISSN 2469-9926 R&D Projects: GA ČR GAP205/12/0382 Institutional support: RVO:68378271 Keywords : Bell nonlocality * fully entangled fraction * entanglement-swapping device * quantum state tomography Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 2.925, year: 2016

Molecular Laser Spectroscopy as a Tool for Gas Analysis Applications

Directory of Open Access Journals (Sweden)

Javis Anyangwe Nwaboh

2011-01-01

Full Text Available We have used the traceable infrared laser spectrometric amount fraction measurement (TILSAM method to perform absolute concentration measurements of molecular species using three laser spectroscopic techniques. We report results performed by tunable diode laser absorption spectroscopy (TDLAS, quantum cascade laser absorption spectroscopy (QCLAS, and cavity ring down spectroscopy (CRDS, all based on the TILSAM methodology. The measured results of the different spectroscopic techniques are in agreement with respective gravimetric values, showing that the TILSAM method is feasible with all different techniques. We emphasize the data quality objectives given by traceability issues and uncertainty analyses.

Transient Infrared Measurement of Laser Absorption Properties of Porous Materials

Directory of Open Access Journals (Sweden)

Marynowicz Andrzej

2016-06-01

Full Text Available The infrared thermography measurements of porous building materials have become more frequent in recent years. Many accompanying techniques for the thermal field generation have been developed, including one based on laser radiation. This work presents a simple optimization technique for estimation of the laser beam absorption for selected porous building materials, namely clinker brick and cement mortar. The transient temperature measurements were performed with the use of infrared camera during laser-induced heating-up of the samples’ surfaces. As the results, the absorbed fractions of the incident laser beam together with its shape parameter are reported.

Transient Infrared Measurement of Laser Absorption Properties of Porous Materials

Science.gov (United States)

Marynowicz, Andrzej

2016-06-01

The infrared thermography measurements of porous building materials have become more frequent in recent years. Many accompanying techniques for the thermal field generation have been developed, including one based on laser radiation. This work presents a simple optimization technique for estimation of the laser beam absorption for selected porous building materials, namely clinker brick and cement mortar. The transient temperature measurements were performed with the use of infrared camera during laser-induced heating-up of the samples' surfaces. As the results, the absorbed fractions of the incident laser beam together with its shape parameter are reported.

Application of a particle separation device to reduce inductively coupled plasma-enhanced elemental fractionation in laser ablation-inductively coupled plasma-mass spectrometry

International Nuclear Information System (INIS)

Guillong, Marcel; Kuhn, Hans-Rudolf; Guenther, Detlef

2003-01-01

The particle size distribution of laser ablation aerosols are a function of the wavelength, the energy density and the pulse duration of the laser, as well as the sample matrix and the gas environment. Further the size of the particles affects the vaporization and ionization efficiency in the inductively coupled plasma (ICP). Some matrices produce large particles, which are not completely vaporized and ionized in the ICP. The previous work has shown that analytical results such as matrix-independent calibration, accuracy and precision can be significantly influenced by the particle sizes of the particles. To minimize the particle size related incomplete conversion of the sample to ions in the ICP a particle separation device was developed, which allows effective particle separation using centrifugal forces in a thin coiled tube. In this device, the particle cut-off size is varied by changing the number of turns in the coil, as well as by changing the gas flow and the tube diameter. The interaction of the laser with the different samples leads to varying particle size distributions. When carrying out quantitative analysis with non-matrix matched calibration reference materials, it was shown that different particle cut-off sizes were required depending on the ICP conditions and the instrument used for analysis. Various sample materials were investigated in this study to demonstrate the applicability of the device. For silicate matrices, the capability of the ICP to produce ions was significantly reduced for particles larger than 0.5 μm, and was dependent on the element monitored. To reduce memory effects caused by the separated particles, a washout procedure was developed, which additionally allowed the analysis of the trapped particles. These results clearly demonstrate the very important particle size dependent ICP-MS signal response and the potential of the described particle size based separator for the reduction of ICP induced elemental fractionation

Diminution of acute radiation reaction of mouse skin with low-intensity infrared laser/red diodes-emitted light

International Nuclear Information System (INIS)

Meshcherikova, V.V.; Klimakov, B.D.; Goldobenko, G.V.; Vajnson, A.A.

2000-01-01

Efficiency of the application of different regimes of laser treatment of radiation-induced skin reactions in mice feet is compared. Posterior limb feet of mice were exposed to acute X radiation at 30-36 Gy dose or fractionated radiation at 45 Gy dose. In the day of primary irradiation or different time later the feet were treated using magnetic infrared laser therapeutic MILTA-01 apparatus. Magnetic and light components of the MILTA-01 apparatus reduce the effect of radiation on mice skin corresponding two time decrease in X-radiation dose [ru

Comparison of layer grain size analysis with pipette and sieve analysis: a solution for the underestimation of the clay fraction

NARCIS (Netherlands)

Konert, M.; Vandenberghe, J.F.

1997-01-01

Classically, the grain size of soil and sediment samples is determined by the sieve method for the coarse fractions and by the pipette method, based on the 'Stokes' sedimentation rates, for the fine fractions. Results from the two methods are compared with results from laser diffraction size

Controlled intra- and transdermal protein delivery using a minimally invasive Erbium:YAG fractional laser ablation technology.

Science.gov (United States)

Bachhav, Y G; Heinrich, A; Kalia, Y N

2013-06-01

The aim of the study was (i) to investigate the feasibility of using fractional laser ablation to create micropore arrays in order to deliver proteins into and across the skin and (ii) to demonstrate how transport rates could be controlled by variation of poration and formulation conditions. Four proteins with very different structures and properties were investigated - equine heart cytochrome c (Cyt c; 12.4 kDa), recombinant human growth hormone expressed in Escherichia coli (hGH; 22 kDa), urinary follicle stimulating hormone (FSH; 30 kDa) and FITC-labelled bovine serum albumin (FITC-BSA; 70 kDa). The transport experiments were performed using a scanning Er:YAG diode pumped laser (P.L.E.A.S.E.®; Precise Laser Epidermal System). The distribution of FITC-BSA in the micropores following P.L.E.A.S.E.® poration was visualised by using confocal laser scanning microscopy (CLSM). Porcine skin was used for the device parameter and CLSM studies; its validity as a model was confirmed by subsequent comparison with transport of Cyt c and FITC-BSA across P.L.E.A.S.E.® porated human skin. No protein transport (deposition or permeation) was observed across intact skin; however, P.L.E.A.S.E.® poration enabled total delivery after 24h of 48.2±8.9, 8.1±4.2, 0.2±0.1 and 273.3±30.6 μg/cm(2) for Cyt c, hGH, FSH and FITC-BSA, respectively, using 900 pores/135.9 cm(2). Calculation of permeability coefficients showed that there was no linear dependence of transport on molecular weight ((1.6±0.3), (0.1±0.05), (0.08±0.03) and (0.9±0.1)×10(-3) cm/h, for Cyt c, hGH, FSH and FITC-BSA, respectively); indeed, a U-shaped curve was observed. This suggested that molecular weight was not a sufficiently sensitive descriptor and that transport was more likely to be determined by the surface properties of the respective proteins since these would govern interactions with the local microenvironment. Increasing pore density (i.e. the number of micropores per unit area) had a statistically

Non-ablative fractional resurfacing in combination with topical tretinoin cream as a field treatment modality for multiple actinic keratosis: a pilot study and a review of other field treatment modalities.

Science.gov (United States)

Prens, Sebastiaan P; de Vries, Karin; Neumann, H A Martino; Prens, Errol P

2013-06-01

Actinic keratoses (AK) are premalignant lesions occurring mainly in sun-damaged skin. Current topical treatment options for AK and photo-damaged skin such as liquid nitrogen and electrosurgery are not suitable for field treatment. Otherwise, therapies suitable for field treatment bring along considerable patient discomfort. Non-ablative fractional resurfacing has emerged as a logical treatment option especially for field treatment of AK. To evaluate the clinical efficacy of fractional laser therapy for clearing AK and improving skin quality. To compare patient friendliness of the "fractional" therapy with those reported for other field treatment modalities. Ten patients with Fitzpatrick skin type I to III with multiple AK and extensive sun-damaged skin, received 5-10 sessions with a 4-week interval using a 1550 nm Erbium-Glass Fractionated laser (Sellas, Korea). Four weeks and 24 weeks after the last treatment the clinical results were evaluated by an independent physician. The mean degree of improvement, in terms of reduction in the number of AK and improvement of skin texture, was 54% on a 4 point PGA scale, and persisted for approximately 6 months. The biggest advantage of fractional laser treatment, besides the eradication of AK and a clear rejuvenation effect, is the absence of "downtime". Fractional non-ablative resurfacing induces significant reduction in the number of AK and improves the skin quality. Also all patients preferred fractional laser therapy above other AK treatment modalities.

COMPARING PARTICLE SIZE DISTRIBUTION ANALYSIS BY SEDIMENTATION AND LASER DIFFRACTION METHOD

OpenAIRE

Vito Ferro; Stefano Mirabile

2009-01-01

In this paper a brief review of the laser diffraction method is firstly carried out. Then, for 30 soil samples having a different texture classification sampled in Sicilian basin, a comparison between the two techniques is developed. The analysis demonstrated that the sand content measured by Sieve-Hydrometer method can be assumed equal to the one determinated by laser diffraction technique while an overestimation of the clay fraction measured by Sieve-Hydrometer method respect to laser diffr...

Correlation of histological findings of single session Er:YAG skin fractional resurfacing with various passes and energies and the possible clinical implications.

Science.gov (United States)

Trelles, Mario A; Vélez, Mariano; Mordon, Serge

2008-03-01

Ablative fractional resurfacing shows promise for skin resurfacing and tightening and also to improve treatment of epidermal and dermal pigmentary disorders. This study aimed at determining any correlation between epidermal ablation and effects on the dermis when using an Er:YAG laser in ablative fractional resurfacing mode. Ten female subjects participated in the study, mean age 52 years, Skin phototypes: 1 Fitzpatrick type II; 8 type III and 1 type IV. The degree of wrinkles (Glogau scale II or III) was similar in all cases. The laser used was the Pixel Er:YAG system (Alma Lasertrade mark, Israel) which delivers the laser beam via a hand-piece equipped with a beam splitter to divide the 2,940 nm beam into various microbeams of 850 microm in diameter in an 11 mmx11 mm treatment area. Using a constant energy of 1,400 mJ/cm(2), on a test area of 4 cmx2 cm. Two, 4, 6, and 8 passes on the preauricular area of the face were evaluated immediately after treatment. In all cases, the handpiece was kept in the same position, and rotated slightly around its perpendicular axis between passes, then moved on to the next spot. Biopsies were performed and tissue samples were routinely processed and stained with hematoxylin and eosin (H&E). No patient reported any noticeable discomfort, even at 8 passes. The histological findings revealed that, independent of the degree of the wrinkles, more laser passes produced more ablative removal of the epidermis. Residual thermal damage (RTD) with 2 laser passes was not observed but with 4 and 6 passes increased thermal effects and vacuole formation in the epidermal cells were noticed. With 8 laser passes, total epidermal removal was seen together with frank RTD-related changes in the upper part of the papillary dermis. In this study, we have demonstrated that high density fractional Er:YAG laser energy in a single session with multiple passes targeted not only the skin surface with elimination of the epidermis, but could also achieve heat

Fractional Fourier transform for confluent hypergeometric beams

International Nuclear Information System (INIS)

Tang, Bin; Jiang, Chun; Zhu, Haibin

2012-01-01

Based on the definition of the fractional Fourier transform (FRFT) in the cylindrical coordinate system, the propagation properties of a new family of paraxial laser beams named confluent hypergeometric (HyG) beams, of which intensity profile is similar to that for the Bessel modes, passing through FRFT optical systems have been studied in detail by some typical numerical examples. The results indicate that the normalized intensity distribution of a HyG beam in the FRFT plane is closely related to not only the fractional order p but also the beam parameters m,n, and focal length f. -- Highlights: ► We study the propagation of a HyG beam through FRFT optical systems. ► The intensity of the beam in the FRFT plane is closely related to some parameters. ► We can control the properties of HyG beams by properly choosing the parameters.

Inductively Coupled Plasma: Fundamental Particle Investigations with Laser Ablation and Applications in Magnetic Sector Mass Spectrometry

International Nuclear Information System (INIS)

Nathan Joe Saetveit

2008-01-01

Particle size effects and elemental fractionation in laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) are investigated with nanosecond and femtosecond laser ablation, differential mobility analysis, and magnetic sector ICP-MS. Laser pulse width was found to have a significant influence on the LA particle size distribution and the elemental composition of the aerosol and thus fractionation. Emission from individual particles from solution nebulization, glass, and a pressed powder pellet are observed with high speed digital photography. The presence of intact particles in an ICP is shown to be a likely source of fractionation. A technique for the online detection of stimulated elemental release from neural tissue using magnetic sector ICP-MS is described. Detection limits of 1 (micro)g L -1 or better were found for P, Mn, Fe, Cu, and Zn in a 60 (micro)L injection in a physiological saline matrix

Laser-plasma interactions for fast ignition

Science.gov (United States)

Kemp, A. J.; Fiuza, F.; Debayle, A.; Johzaki, T.; Mori, W. B.; Patel, P. K.; Sentoku, Y.; Silva, L. O.

2014-05-01

In the electron-driven fast-ignition (FI) approach to inertial confinement fusion, petawatt laser pulses are required to generate MeV electrons that deposit several tens of kilojoules in the compressed core of an imploded DT shell. We review recent progress in the understanding of intense laser-plasma interactions (LPI) relevant to FI. Increases in computational and modelling capabilities, as well as algorithmic developments have led to enhancement in our ability to perform multi-dimensional particle-in-cell simulations of LPI at relevant scales. We discuss the physics of the interaction in terms of laser absorption fraction, the laser-generated electron spectra, divergence, and their temporal evolution. Scaling with irradiation conditions such as laser intensity are considered, as well as the dependence on plasma parameters. Different numerical modelling approaches and configurations are addressed, providing an overview of the modelling capabilities and limitations. In addition, we discuss the comparison of simulation results with experimental observables. In particular, we address the question of surrogacy of today's experiments for the full-scale FI problem.

Laser-induced reversion of δ′ precipitates in an Al-Li alloy: Study on temperature rise in pulsed laser atom probe

KAUST Repository

Khushaim, Muna Saeed Amin

2016-06-14

The influence of tuning the laser pulse energy during the analyses on the resulting microstructure in a specimen utilizing an ultra-fast laser assisted atom probe was demonstrated by a case study of a binary Al-Li alloy. The decomposition parameters, such as the size, number density, volume fraction, and composition of δ\\' precipitates, were carefully monitored after each analysis. A simple model was employed to estimate the corresponding specimen temperature for each value of the laser energy. The results indicated that the corresponding temperatures for the laser pulse energy in the range of 10 to 80 pJ are located inside the miscibility gap of the binary Al-Li phase diagram and fall into the metastable equilibrium field. In addition, the corresponding temperature for a laser pulse energy of 100 pJ was in fairly good agreement with reported range of δ\\' solvus temperature, suggesting a result of reversion upon heating due to laser pulsing. © 2016 Wiley Periodicals, Inc.

Laser-induced reversion of δ′ precipitates in an Al-Li alloy: Study on temperature rise in pulsed laser atom probe

KAUST Repository

Khushaim, Muna Saeed Amin; Gemma, Ryota; Al-Kassab, Talaat

2016-01-01

The influence of tuning the laser pulse energy during the analyses on the resulting microstructure in a specimen utilizing an ultra-fast laser assisted atom probe was demonstrated by a case study of a binary Al-Li alloy. The decomposition parameters, such as the size, number density, volume fraction, and composition of δ' precipitates, were carefully monitored after each analysis. A simple model was employed to estimate the corresponding specimen temperature for each value of the laser energy. The results indicated that the corresponding temperatures for the laser pulse energy in the range of 10 to 80 pJ are located inside the miscibility gap of the binary Al-Li phase diagram and fall into the metastable equilibrium field. In addition, the corresponding temperature for a laser pulse energy of 100 pJ was in fairly good agreement with reported range of δ' solvus temperature, suggesting a result of reversion upon heating due to laser pulsing. © 2016 Wiley Periodicals, Inc.

Skin pre-ablation and laser assisted microjet injection for deep tissue penetration.

Science.gov (United States)

Jang, Hun-Jae; Yeo, Seonggu; Yoh, Jack J

2017-04-01

For conventional needless injection, there still remain many unresolved issues such as the potential for cross-contamination, poor reliability of targeted delivery dose, and significantly painstaking procedures. As an alternative, the use of microjets generated with Er:YAG laser for delivering small doses with controlled penetration depths has been reported. In this study, a new system with two stages is evaluated for effective transdermal drug delivery. First, the skin is pre-ablated to eliminate the hard outer layer and second, laser-driven microjet penetrates the relatively weaker and freshly exposed epidermis. Each stage of operation shares a single Er:YAG laser that is suitable for skin ablation as well as for the generation of a microjet. In this study, pig skin is selected for quantification of the injection depth based on the two-stage procedure, namely pre-ablation and microjet injection. The three types of pre-ablation devised here consists of bulk ablation, fractional ablation, and fractional-rotational ablation. The number of laser pulses are 12, 18, and 24 for each ablation type. For fractional-rotational ablation, the fractional beams are rotated by 11.25° at each pulse. The drug permeation in the skin is evaluated using tissue marking dyes. The depth of penetration is quantified by a cross sectional view of the single spot injections. Multi-spot injections are also carried out to control the dose and spread of the drug. The benefits of a pre-ablation procedure prior to the actual microjet injection to the penetration is verified. The four possible combinations of injection are (a) microjet only; (b) bulk ablation and microjet injection; (c) fractional ablation and microjet injection; and (d) fractional-rotational ablation and microjet injection. Accordingly, the total depth increases with injection time for all cases. In particular, the total depth of penetration attained via fractional pre-ablation increased by 8 ∼ 11% and that of fractional

Skin optical clearing for improvement of laser tattoo removal

Science.gov (United States)

Bashkatov, A. N.; Genina, E. A.; Tuchin, V. V.; Altshuler, G. B.

2009-06-01

The possibility of improvement of laser tattoo removal due to the optical clearing of human skin is investigated. It is shown experimentally that previously perforation of skin stratum corneum allows increasing tattoo image contrast at topical administration of immersion agent in contrast with non-perforated skin. Computer Monte Carlo simulation shows that at the optical clearing of upper skin layers the tattoo image contrast and the photon fraction absorbed in the tattoo area at the depths of 0.5 or 1.0 mm increase, that allows significant decreasing of the power of laser radiation used at laser thermolysis.

Instantaneous temperature field measurements using planar laser-induced fluorescence.

Science.gov (United States)

Seitzman, J M; Kychakoff, G; Hanson, R K

1985-09-01

A single-pulse, laser-induced-fluorescence diagnostic for the measurement of two-dimensional temperature fields in combustion flows is described. The method uses sheet illumination from a tunable laser to excite planar laserinduced fluorescence in a stable tracer molecule, seeded at constant mole fraction into the flow field. The temporal resolution of this technique is determined by the laser pulse length. Experimental results are presented for a rodstabilized, premixed methane-air flame, using the Q(1) (22) line of the nitric oxide A(2) Sigma(+) (v = 0) ? X(2)II((1/2))(v = 0) transition (lambda approximately 225.6 nm).

Polarization dependence of laser interaction with carbon fibers and CFRP.

Science.gov (United States)

Freitag, Christian; Weber, Rudolf; Graf, Thomas

2014-01-27

A key factor for laser materials processing is the absorptivity of the material at the laser wavelength, which determines the fraction of the laser energy that is coupled into the material. Based on the Fresnel equations, a theoretical model is used to determine the absorptivity for carbon fiber fabrics and carbon fiber reinforced plastics (CFRP). The surface of each carbon fiber is considered as multiple layers of concentric cylinders of graphite. With this the optical properties of carbon fibers and their composites can be estimated from the well-known optical properties of graphite.

Microstructure and wear resistance of laser cladded Ni-Cr-Co-Ti-V high-entropy alloy coating after laser remelting processing

Science.gov (United States)

Cai, Zhaobing; Cui, Xiufang; Liu, Zhe; Li, Yang; Dong, Meiling; Jin, Guo

2018-02-01

An attempt, combined with the technologies of laser cladding and laser remelting, has been made to develop a Ni-Cr-Co-Ti-V high entropy alloy coating. The phase composition, microstructure, micro-hardness and wear resistance (rolling friction) were studied in detail. The results show that after laser remelting, the phase composition remains unchanged, that is, as-cladded coating and as-remelted coatings are all composed of (Ni, Co)Ti2 intermetallic compound, Ti-rich phase and BCC solid solution phase. However, after laser remelting, the volume fraction of Ti-rich phase increases significantly. Moreover, the micro-hardness is increased, up to ∼900 HV at the laser remelting parameters: laser power of 1 kW, laser spot diameter of 3 mm, and laser speed of 10 mm/s. Compared to the as-cladded high-entropy alloy coating, the as-remelted high-entropy alloy coatings have high friction coefficient and low wear mass loss, indicating that the wear resistance of as-remelted coatings is improved and suggesting practical applications, like coatings on brake pads for wear protection. The worn surface morphologies show that the worn mechanism of as-cladded and as-remelted high-entropy alloy coatings are adhesive wear.

Evaporation Induced Oxygen Isotope Fractionation in Impact Ejecta

Science.gov (United States)

Macris, C. A.; Young, E. D.; Kohl, I. E.; zur Loye, T. E.

2017-12-01

Tektites are natural glasses formed as quenched impact melt ejecta. Because they experienced extreme heating while entrained in a hot impact vapor plume, tektites allow insight into the nature of these ephemeral events, which play a critical role in planetary accretion and evolution. During tektite formation, the chemical and isotopic composition of parent materials may be modified by (1) vapor/liquid fractionation at high T in the plume, (2) incorporation of meteoric water at the target site, (3) isotope exchange with atmospheric oxygen (if present), or some combination of the three. Trends from O isotope studies reveal a dichotomy: some tektite δ18O values are 4.0-4.5‰ lower than their protoliths (Luft et al. 1987; Taylor & Epstein 1962), opposite in direction to a vaporization induced fractionation; increases in δ18O with decreasing SiO2 in tektites (Taylor & Epstein 1969) is consistent with vapor fractionation. Using an aerodynamic levitation laser furnace (e.g. Macris et al. 2016), we can experimentally determine the contributions of processes (1), (2) and (3) above to tektite compositions. We conducted a series of evaporation experiments to test process (1) using powdered tektite fused into 2 mm spheres and heated to 2423-2473 K for 50-90 s while levitated in Ar in the furnace. Mass losses were from 23 to 26%, reflecting evaporation of Si and O from the melt. The starting tektite had a δ18O value of 10.06‰ (±0.01 2se) and the residues ranged from 13.136‰ (±0.006) for the least evaporated residue to 14.30‰ (±0.02) for the most evaporated (measured by laser fluorination). The increase in δ18O with increasing mass loss is consistent with Rayleigh fractionation during evaporation, supporting the idea that O isotopes are fractionated due to vaporization at high T in an impact plume. Because atmospheric O2 and water each have distinctive Δ17O values, we should be able to use departures from our measured three-isotope fractionation law to evaluate

Evaluation of Laser-Assisted Trans-Nail Drug Delivery with Optical Coherence Tomography

Directory of Open Access Journals (Sweden)

Meng-Tsan Tsai

2016-12-01

Full Text Available The nail provides a functional protection to the fingertips and surrounding tissue from external injuries. The nail plate consists of three layers including dorsal, intermediate, and ventral layers. The dorsal layer consists of compact, hard keratins, limiting topical drug delivery through the nail. In this study, we investigate the application of fractional CO2 laser that produces arrays of microthermal ablation zones (MAZs to facilitate drug delivery in the nails. We utilized optical coherence tomography (OCT for real-time monitoring of the laser–skin tissue interaction, sparing the patient from an invasive surgical sampling procedure. The time-dependent OCT intensity variance was used to observe drug diffusion through an induced MAZ array. Subsequently, nails were treated with cream and liquid topical drugs to investigate the feasibility and diffusion efficacy of laser-assisted drug delivery. Our results show that fractional CO2 laser improves the effectiveness of topical drug delivery in the nail plate and that OCT could potentially be used for in vivo monitoring of the depth of laser penetration as well as real-time observations of drug delivery.

Diffuse scattering from laser-irradiated plane targets

International Nuclear Information System (INIS)

Kessel, C.G.M. van; Olsen, J.N.; Sachsenmaier, P.; Sigel, R.; Eidmann, K.; Godwin, R.P.

1976-11-01

Optical calorimetry of the laser radiation scattered from plane targets irradiated by 0.3 Joule/30 ps Nd-laser pulses with intensities up to 10 16 W cm -2 has been performed with an emphasis on diffuse scattering. Diffuse scattering outside the solid angle of the focusing lens is found to be a major reflection loss from the target. A fraction of 0.3 to 0.5 of the incident pulse energy was absorbed in the target with only a very weak dependence on pulse energy and target material. (orig.) [de

Absorption of femtosecond laser pulses by atomic clusters

International Nuclear Information System (INIS)

Lin Jingquan; Zhang Jie; Li Yingjun; Chen Liming; Lu Tiezheng; Teng Hao

2001-01-01

Energy absorption by Xe, Ar, He atomic clusters are investigated using laser pulses with 5 mJ energy in 150 fs duration. Experimental results show that the size of cluster and laser absorption efficiency are strongly dependent on several factors, such as the working pressure of pulse valve, atomic number Z of the gas. Absorption fraction of Xe clusters is as high as 45% at a laser intensity of 1 x 10 15 W/cm 2 with 20 x 10 5 Pa gas jet backing pressure. Absorption of the atomic clusters is greatly reduced by introducing pre-pulses. Ion energy measurements confirm that the efficient energy deposition results in a plasma with very high ion temperature

Comparative Study Using Autologous Fat Grafts Plus Platelet-Rich Plasma With or Without Fractional CO2 Laser Resurfacing in Treatment of Acne Scars: Analysis of Outcomes and Satisfaction With FACE-Q.

Science.gov (United States)

Tenna, S; Cogliandro, A; Barone, M; Panasiti, Vincenzo; Tirindelli, M; Nobile, Carolina; Persichetti, Paolo

2017-06-01

A multitude of options are traditionally used for the treatment of acne scars; however, newer treatment modalities are emerging to decrease the propensity for post-inflammatory hyperpigmentation and upregulate new collagen production. The aim of this study was to evaluate the efficacy of nanofat and platelet-rich plasma (PRP) infiltration alone and combined with fractional CO 2 laser resurfacing to improve atrophic scars of the face. From March 2014 to June 2015, 30 patients with atrophic acne scars on the cheeks were selected for this study. Patients were evaluated pre- and postoperatively by physical examination, photographs and ultrasound with a 22-MHz probe to measure subcutaneous tissue thickness. All patients were treated with infiltration of nanofat plus PRP. The production of PRP was achieved using the RegenLab THT tube ® method. In 15 randomly chosen patients, a fractional CO 2 laser resurfacing at 15 W was also performed right after the infiltration. An Italian version of the FACE-Q postoperative module was administered to analyze each patient's satisfaction and aesthetic perception of the result. The average preoperative thickness of subcutaneous tissue of patients from group A was 0.532 cm, while the average preoperative thickness of subcutaneous tissue of patients from group B was 0.737 cm. The average postoperative thickness of subcutaneous tissue was 1.201 cm in group A and 1.367 cm in group B. The improvement of thickness of subcutaneous tissue was 0.668 cm in group A and 0.63 cm in group B. We applied a t test on unpaired data, comparing the difference in thickness obtained with the treatment in both group A and in group B, with a p value =0.7289 (not significant). All patients in both groups had a treatment benefit, confirmed with FACE-Q postoperative module, but without a significant difference between the two groups. Subcutaneous infiltration with nanofat and PRP seems to be effective to improve atrophic scars, either alone or combined

Multi-pulse enhanced laser ion acceleration using plasma half cavity targets

International Nuclear Information System (INIS)

Scott, G. G.; Brenner, C. M.; Neely, D.; Green, J. S.; Robinson, A. P. L.; Spindloe, C.; Bagnoud, V.; Brabetz, C.; Zielbauer, B.; Carroll, D. C.; MacLellan, D. A.; McKenna, P.; Roth, M.; Wagner, F.

2012-01-01

We report on a plasma half cavity target design for laser driven ion acceleration that enhances the laser to proton energy conversion efficiency and has been found to modify the low energy region of the proton spectrum. The target design utilizes the high fraction of laser energy reflected from an ionized surface and refocuses it such that a double pulse interaction is attained. We report on numerical simulations and experimental results demonstrating that conversion efficiencies can be doubled, compared to planar foil interactions, when the secondary pulse is delivered within picoseconds of the primary pulse.

Multi-pulse enhanced laser ion acceleration using plasma half cavity targets

Energy Technology Data Exchange (ETDEWEB)

Scott, G. G.; Brenner, C. M.; Neely, D. [Central Laser Facility, STFC Rutherford Appleton Laboratory, OX11 0QX Didcot (United Kingdom); Department of Physics SUPA, University of Strathclyde, G4 0NG Glasgow (United Kingdom); Green, J. S.; Robinson, A. P. L.; Spindloe, C. [Central Laser Facility, STFC Rutherford Appleton Laboratory, OX11 0QX Didcot (United Kingdom); Bagnoud, V.; Brabetz, C.; Zielbauer, B. [PHELIX Group, Gesellschaft fuer Schwerionenforschung, D-64291 Darmstadt (Germany); Carroll, D. C.; MacLellan, D. A.; McKenna, P. [Department of Physics SUPA, University of Strathclyde, G4 0NG Glasgow (United Kingdom); Roth, M. [Fachbereich Physik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany); Wagner, F. [PHELIX Group, Gesellschaft fuer Schwerionenforschung, D-64291 Darmstadt (Germany); Fachbereich Physik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany)

2012-07-09

We report on a plasma half cavity target design for laser driven ion acceleration that enhances the laser to proton energy conversion efficiency and has been found to modify the low energy region of the proton spectrum. The target design utilizes the high fraction of laser energy reflected from an ionized surface and refocuses it such that a double pulse interaction is attained. We report on numerical simulations and experimental results demonstrating that conversion efficiencies can be doubled, compared to planar foil interactions, when the secondary pulse is delivered within picoseconds of the primary pulse.

Lambda shifted photonic crystal cavity laser

DEFF Research Database (Denmark)

Schubert, Martin; Skovgård, Troels Suhr; Ek, Sara

2010-01-01

We propose and demonstrate an alternative type of photonic crystal laser design that shifts all the holes in the lattice by a fixed fraction of the targeted emission wavelength. The structures are realized in InGaAsP =1.15 with InGaAsP quantum wells =1.52 as gain material. Cavities with shifts of...

Iron isotope composition of particles produced by UV-femtosecond laser ablation of natural oxides, sulfides, and carbonates.

Science.gov (United States)

d'Abzac, Francois-Xavier; Beard, Brian L; Czaja, Andrew D; Konishi, Hiromi; Schauer, James J; Johnson, Clark M

2013-12-17

The need for femtosecond laser ablation (fs-LA) systems coupled to MC-ICP-MS to accurately perform in situ stable isotope analyses remains an open question, because of the lack of knowledge concerning ablation-related isotopic fractionation in this regime. We report the first iron isotope analysis of size-resolved, laser-induced particles of natural magnetite, siderite, pyrrhotite, and pyrite, collected through cascade impaction, followed by analysis by solution nebulization MC-ICP-MS, as well as imaging using electron microscopy. Iron mass distributions are independent of mineralogy, and particle morphology includes both spheres and agglomerates for all ablated phases. X-ray spectroscopy shows elemental fractionation in siderite (C-rich agglomerates) and pyrrhotite/pyrite (S-rich spheres). We find an increase in (56)Fe/(54)Fe ratios of +2‰, +1.2‰, and +0.8‰ with increasing particle size for magnetite, siderite, and pyrrhotite, respectively. Fe isotope differences in size-sorted aerosols from pyrite ablation are not analytically resolvable. Experimental data are discussed using models of particles generation by Hergenröder and elemental/isotopic fractionation by Richter. We interpret the isotopic fractionation to be related to the iron condensation time scale, dependent on its saturation in the gas phase, as a function of mineral composition. Despite the isotopic variations across aerosol size fractions, total aerosol composition, as calculated from mass balance, confirms that fs-LA produces a stoichiometric sampling in terms of isotopic composition. Specifically, both elemental and isotopic fractionation are produced by particle generation processes and not by femtosecond laser-matter interactions. These results provide critical insights into the analytical requirements for laser-ablation-based stable isotope measurements of high-precision and accuracy in geological samples, including the importance of quantitative aerosol transport to the ICP.

Designing Fresnel microlenses for focusing astigmatic multi-Gaussian beams by using fractional order Fourier transforms

International Nuclear Information System (INIS)

Patino, A; Durand, P-E; Fogret, E; Pellat-Finet, P

2011-01-01

According to a scalar theory of diffraction, light propagation can be expressed by two-dimensional fractional order Fourier transforms. Since the fractional Fourier transform of a chirp function is a Dirac distribution, focusing a light beam is optically achieved by using a diffractive screen whose transmission function is a two-dimensional chirp function. This property is applied to designing Fresnel microlenses, and the orders of the involved Fourier fractional transforms depend on diffraction distances as well as on emitter and receiver radii of curvature. If the emitter is astigmatic (with two principal radii of curvature), the diffraction phenomenon involves two one-dimensional fractional Fourier transforms whose orders are different. This degree of freedom allows us to design microlenses that can focus astigmatic Gaussian beams, as produced by a line-shaped laser diode source.

UNS S32750 super duplex steel welding using pulsed Nd:YAG laser; Soldagem do aco superduplex UNS S32750 com laser pulsado Nd:YAG

Energy Technology Data Exchange (ETDEWEB)

Francini, O.D.; Andrade, G.G.; Clemente, M.S.; Gallego, J.; Ventrella, V.A., E-mail: ventrella@dem.feis.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Ilha Solteira, SP (Brazil). Departamento de Engenharia Mecanica

2016-07-01

Laser is a flexible and powerful tool with many relevant applications in industry, mainly in the welding area. Lasers today provide the welding industry technical solutions to many problems. This work studied the weld metal obtained by pulsed laser welding of Nd: YAG super duplex stainless steel UNS S32750 employed in the oil and natural gas, analyzing the influence of high cooling rate, due to the laser process, the swing phase ferrite / austenite. Were performed weld beads in butt joint with different repetition rates. The different microstructures were obtained by optical microscopy and scanning electron microscopy. The results showed that the effect of varying the welding energy of Nd: YAG laser on the volume fractions of the phases ferrite/austenite in the weld metal was its ferritization and low austenite amount on the grain boundary. (author)

Colloidal transport of uranium in soil: Size fractionation and characterization by field-flow fractionation-multi-detection

International Nuclear Information System (INIS)

Claveranne-Lamolere, C.; Lespes, G.; Dubascoux, St.; Potin-Gautier, M.; Claveranne-Lamolere, C.; Aupiais, J.; Pointurier, F.

2009-01-01

The aim of this study was to characterize colloids associated with uranium by using an on-line fractionation/multi-detection technique based on asymmetrical flow field-flow fractionation (As-Fl-FFF) hyphenated with UV detector, multi angle laser light scattering (MALLS) and inductively coupling plasma-mass spectrometry (ICP-MS). Moreover, thanks to the As-Fl-FFF, the different colloidal fractions were collected and characterized by a total organic carbon analyzer (TOC). Thus it is possible to determine the nature (organic or inorganic colloids), molar mass, size (gyration and hydrodynamic radii) and quantitative uranium distribution over the whole colloidal phase. In the case of the site studied, two populations are highlighted. The first population corresponds to humic-like substances with a molar mass of (1500 ± 300) g mol -1 and a hydrodynamic diameter of (2. 0 ± 0. 2) nm. The second one has been identified as a mix of carbonated nano-particles or clays with organic particles (aggregates and/or coating of the inorganic particles) with a size range hydrodynamic diameter between 30 and 450 nm. Each population is implied in the colloidal transport of uranium: maximum 1% of the uranium content in soil leachate is transported by the colloids in the site studied, according to the depth in the soil. Indeed, humic substances are the main responsible of this transport in sub-surface conditions whereas nano-particles drive the phenomenon in depth conditions. (authors)

Effect of laser-plasma X-ray irradiation on crystallization of amorphous silicon film by excimer laser annealing

International Nuclear Information System (INIS)

Matsuo, Naoto; Uejukkoku, Kazuya; Heya, Akira; Takanashi, Yasuyuki; Amano, Sho; Miyamoto, Shuji; Mochizuki, Takayasu

2007-01-01

The effect of laser plasma soft X-ray (LPX) irradiation on crystallization by excimer laser annealing (ELA) was investigated at low ELA energy densities. The crystalline fraction at energy densities of 50 and 60 mJ/cm 2 for LPX followed by ELA is nearly equal to that at 80 to 100 mJ/cm 2 for the ELA method with non-LPX irradiation. The results obtained indicate that LPX irradiation before ELA reduces the critical energy density for the start of crystallization. The combined method of LPX irradiation and ELA will enable us to realize a low-temperature process for ELA crystallization. (author)

Laser-assisted delivery of topical methotrexate - in vitro investigations

DEFF Research Database (Denmark)

Taudorf, Elisabeth Hjardem

2016-01-01

of the correlation between laser parameters and tissue effects was used to deliver methotrexate (MTX) topically through microscopic ablation zones (MAZs) of precise dimensions. MTX is a well-known chemotherapeutic and anti-inflammatory drug that may cause systemic adverse effects, and topical delivery is thus......Ablative fractional lasers (AFXL) are increasingly used to treat dermatological disorders and to facilitate laser-assisted topical drug delivery. In this thesis, laser-tissue interactions generated by stacked pulses with a miniaturized low-power 2,940 nm AFXL were characterized (study I). Knowledge...... zones of varying thickness. The ratio of skin deposition versus transdermal permeation was constant, regardless of MAZ depth. Impact of transport kinetics on AFXL-assisted topical MTX delivery: MTX accumulated rapidly in AFXL-processed skin. MTX was detectable in mid-dermis after 15 min. and saturated...

Laser Cooling and Slowing of a Diatomic Molecule

Science.gov (United States)

2013-12-01

124]. For this example, we assume Mik = 0. The population fractions obey nj + Ng∑ i=1 ni = 1, (3.17) 11i.e. no π pulses, stimulated raman adiabatic...expensive for transitions requiring a CW dye laser (∼ $200k) or frequency doubled Raman fiber laser (∼ $120k) since generating light with the ∼ 15 GHz...lower than the mean thermal velocities of He, N2 or H20 at 293 K, which are ≈ 1250, 590 and 470 m/s respectively. Conceptually, the slow SrF molecules

An Investigation into the Relationship Between Distillate Yield and Stable Isotope Fractionation

Science.gov (United States)

Sowers, T.; Wagner, A. J.

2016-12-01

Recent breakthroughs in laser spectrometry have allowed for faster, more efficient analyses of stable isotopic ratios in water samples. Commercially available instruments from Los Gatos Research and Picarro allow users to quickly analyze a wide range of samples, from seawater to groundwater, with accurate isotope ratios of D/H to within ± 0.2 ‰ and 18O/16O to within ± 0.03 ‰. While these instruments have increased the efficiency of stable isotope laboratories, they come with some major limitations, such as not being able to analyze hypersaline waters. The Los Gatos Research Liquid Water Isotope Analyzer (LWIA) can accurately and consistently measure the stable isotope ratios in waters with salinities ranging from 0 to 4 grams per liter (0 to 40 parts per thousand). In order to analyze water samples with salinities greater than 4 grams per liter, however, it was necessary to develop a consistent method through which to reduce salinity while causing as little fractionation as possible. Using a consistent distillation method, predictable fractionation of δ 18O and δ 2 H values was found to occur. This fractionation occurs according to a linear relationship with respect to the percent yield of the water in the sample. Using this method, samples with high salinity can be analyzed using laser spectrometry instruments, thereby enabling laboratories with Los Gatos or Picarro instruments to analyze those samples in house without having to dilute them using labor-intensive in-house standards or expensive premade standards.

Tracking frequency laser distance gauge

International Nuclear Information System (INIS)

Phillips, J.D.; Reasenberg, R.D.

2005-01-01

Advanced astronomical missions with greatly enhanced resolution and physics missions of unprecedented accuracy will require laser distance gauges of substantially improved performance. We describe a laser gauge, based on Pound-Drever-Hall locking, in which the optical frequency is adjusted to maintain an interferometer's null condition. This technique has been demonstrated with pm performance. Automatic fringe hopping allows it to track arbitrary distance changes. The instrument is intrinsically free of the nm-scale cyclic bias present in traditional (heterodyne) high-precision laser gauges. The output is a radio frequency, readily measured to sufficient accuracy. The laser gauge has operated in a resonant cavity, which improves precision, can suppress the effects of misalignments, and makes possible precise automatic alignment. The measurement of absolute distance requires little or no additional hardware, and has also been demonstrated. The proof-of-concept version, based on a stabilized HeNe laser and operating on a 0.5 m path, has achieved 10 pm precision with 0.1 s integration time, and 0.1 mm absolute distance accuracy. This version has also followed substantial distance changes as fast as 16 mm/s. We show that, if the precision in optical frequency is a fixed fraction of the linewidth, both incremental and absolute distance precision are independent of the distance measured. We discuss systematic error sources, and present plans for a new version of the gauge based on semiconductor lasers and fiber-coupled components

Inverse free electron laser accelerator for advanced light sources

Directory of Open Access Journals (Sweden)

J. P. Duris

2012-06-01

Full Text Available We discuss the inverse free electron laser (IFEL scheme as a compact high gradient accelerator solution for driving advanced light sources such as a soft x-ray free electron laser amplifier or an inverse Compton scattering based gamma-ray source. In particular, we present a series of new developments aimed at improving the design of future IFEL accelerators. These include a new procedure to optimize the choice of the undulator tapering, a new concept for prebunching which greatly improves the fraction of trapped particles and the final energy spread, and a self-consistent study of beam loading effects which leads to an energy-efficient high laser-to-beam power conversion.

Robust Frequency Combs and Lasers for Optical Clocks and Sensing, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Optical frequency combs are the key enabling technology that enabled the immense fractional stability of highly-stabilized lasers in the optical regime to be...

COMPARING PARTICLE SIZE DISTRIBUTION ANALYSIS BY SEDIMENTATION AND LASER DIFFRACTION METHOD

Directory of Open Access Journals (Sweden)

Vito Ferro

2009-06-01

Full Text Available In this paper a brief review of the laser diffraction method is firstly carried out. Then, for 30 soil samples having a different texture classification sampled in Sicilian basin, a comparison between the two techniques is developed. The analysis demonstrated that the sand content measured by Sieve-Hydrometer method can be assumed equal to the one determinated by laser diffraction technique while an overestimation of the clay fraction measured by Sieve-Hydrometer method respect to laser diffraction technique was obtained. Finally a set of equations useful to refer LD measurements to SH method was proposed.

Amorphous structure evolution of high power diode laser cladded Fe–Co–B–Si–Nb coatings

International Nuclear Information System (INIS)

Zhu Yanyan; Li Zhuguo; Huang Jian; Li Min; Li Ruifeng; Wu Yixiong

2012-01-01

Highlights: ► Fabricated amorphous composited coating by high power diode laser cladding with single track. ► Lower dilution and higher scanning speed are desired to obtain higher amorphous phase fraction. ► White spots phase with high content of Nb embedded in the amorphous matrix. - Abstract: Fe–Co–B–Si–Nb coatings were fabricated on the surface of low carbon steel using high power diode laser cladding of [(Fe 0.5 Co 0.5 ) 0.75 B 0.2 Si 0.05 ] 95.7 Nb 4.3 amorphous powders at three different scanning speeds of 6, 17 and 50 m/s. At each scanning speed, laser power was optimized to obtain low dilution ratio. Scanning electron microscopy, X-ray diffraction, transmission electron microscopy with energy dispersive spectrometer and electron probe micro analysis were carried out to characterize the microstructure and chemical composition of the cladded coatings. Differential scanning calorimetry was also carried out to investigate the fraction of the amorphous phase. The results showed that dilution ratio and scanning speed were the two main factors for fabricating Fe–Co–B–Si–Nb amorphous coating by high power diode laser cladding. Low dilution ratio was crucial for the formation of amorphous phase. When the dilution ratio was low, the fraction of amorphous phase in the cladded coatings increased upon increasing the scanning speed.

Growth of thin fullerene films by matrix assisted pulsed laser evaporation

DEFF Research Database (Denmark)

Canulescu, Stela; Schou, Jørgen; Fæster, Søren

C60 fullerene thin films of average thickness of more than 100 nm on silicon substrates can be produced in vacuum by matrix-assisted pulsed laser evaporation (MAPLE). A 355 nm Nd:YAG laser was directed onto a frozen target of anisole with a concentration of 0.67 wt% C60. At laser fluences below 1.......5 J/cm2 the dominant fraction of the film molecules are C60 transferred to the substrate without any fragmentation. For high fluences high-resolution SEM images of MAPLE deposited films reveal large circular features on the surface with high amount of material concentrated at edges. These features......, observed over a wide range of laser fluences, are caused by ejection of large matrix-fullerene liquid droplets into the gas-phase and subsequent deposition. At similar laser energies, but using an unfocused laser beam, MAPLE favours evaporation of matrix and organic molecules, resulting in films...

Polymer photonic crystal dye lasers as optofluidic cell sensors

DEFF Research Database (Denmark)

Christiansen, Mads Brøkner; Lopacinska, Joanna M.; Jakobsen, Mogens Havsteen

2009-01-01

Dye doped hybrid polymer lasers are implemented as label free evanescent field biosensors for detection of cells. It is demonstrated that although the coverage is irregular and the cells extend over several lattice constants, the emission wavelength depends linearly on the fraction of the surface...

The Effect of Conditioned Media of Adipose-Derived Stem Cells on Wound Healing after Ablative Fractional Carbon Dioxide Laser Resurfacing

Science.gov (United States)

Zhou, Bing-Rong; Xu, Yang; Guo, Shi-Lei; Xu, Yan; Wang, Ying; Zhu, Fen; Wu, Di; Yin, Zhi-Qiang; Luo, Dan

2013-01-01

Objective. To evaluate the benefits of conditioned medium of Adipose-derived stem cells (ADSC-CM) on wound healing after fractional carbon dioxide laser resurfacing (FxCR) on human skin. Materials and Methods. Nineteen subjects were treated with FxCR on the bilateral inner arms. ADSC-CM was applied on FxCR site of one randomly selected arm. Transepidermal water loss (TEWL), skin color, and gross-elasticity of FxCR site on both arms were measured. Skin samples were taken by biopsy from three subjects 3 weeks after treatment for histopathological manifestations and mRNA expressions of procollagen types I and III, elastin genes were noted. Results. The index of erythema, melanin, and TEWL of the ADSC-CM-treated skin were significantly lower than those of the control side. The mRNA expression of type III procollagen in ADSC-CM-treated group at 3 weeks posttreatment was 2.6 times of that of the control group. Conclusion. Application of allograft ADSC-CM is an effective method for enhancing wound healing after FxCR, by reducing transient adverse effects such as erythema, hyperpigmentation, and increased TEWL. PMID:24381938

The Effect of Conditioned Media of Adipose-Derived Stem Cells on Wound Healing after Ablative Fractional Carbon Dioxide Laser Resurfacing

Directory of Open Access Journals (Sweden)

Bing-Rong Zhou

2013-01-01

Full Text Available Objective. To evaluate the benefits of conditioned medium of Adipose-derived stem cells (ADSC-CM on wound healing after fractional carbon dioxide laser resurfacing (FxCR on human skin. Materials and Methods. Nineteen subjects were treated with FxCR on the bilateral inner arms. ADSC-CM was applied on FxCR site of one randomly selected arm. Transepidermal water loss (TEWL, skin color, and gross-elasticity of FxCR site on both arms were measured. Skin samples were taken by biopsy from three subjects 3 weeks after treatment for histopathological manifestations and mRNA expressions of procollagen types I and III, elastin genes were noted. Results. The index of erythema, melanin, and TEWL of the ADSC-CM-treated skin were significantly lower than those of the control side. The mRNA expression of type III procollagen in ADSC-CM-treated group at 3 weeks posttreatment was 2.6 times of that of the control group. Conclusion. Application of allograft ADSC-CM is an effective method for enhancing wound healing after FxCR, by reducing transient adverse effects such as erythema, hyperpigmentation, and increased TEWL.

Soil Texture Aanalysis by Laser Diffraction – Standardisation Needed

DEFF Research Database (Denmark)

Callesen, Ingeborg; Palviainen, Marjo; Kjoenaas, O. Janne

2017-01-01

sedimentation and sieving methods have been well-defined. From literature and a mini-survey, we know already that laser diffraction is a commonly used analytical method for soil PSD determination in scientific environmental studies that involve soils. A body of literature has documented that colloid......-sized fraction results obtained by laser diffraction analysis of fine-textured soil samples are not comparable to those obtained with sedimentation and sieving methods, when translating to the traditional particle size limits clay, silt and sand. Also, operating procedures for pretreatment of soil samples...... content. We conclude that PSD’s obtained by the laser diffraction method are repeatable and mostly reproducible given standardised pretreatment. Translation to texture class using traditional separates does not work well, and more work and new PTF’s for soils are needed that can translate a laser...

Laser assisted drug delivery: a review of an evolving technology.

Science.gov (United States)

Sklar, Lindsay R; Burnett, Christopher T; Waibel, Jill S; Moy, Ronald L; Ozog, David M

2014-04-01

Topically applied drugs have a relatively low cutaneous bioavailability. This article reviews the existing applications of laser assisted drug delivery, a means by which the permeation of topically applied agents can be enhanced into the skin. The existing literature suggests that lasers are a safe and effective means of enhancing the delivery of topically applied agents through the skin. The types of lasers most commonly studied in regards to drug delivery are the carbon dioxide (CO2 ) and erbium:yttrium-aluminum-garnet (Er:YAG) lasers. Both conventional ablative and fractional ablative modalities have been utilized and are summarized herein. The majority of the existing studies on laser assisted drug delivery have been performed on animal models and additional human studies are needed. Laser assisted drug delivery is an evolving technology with potentially broad clinical applications. Multiple studies demonstrate that laser pretreatment of the skin can increase the permeability and depth of penetration of topically applied drug molecules for both local cutaneous and systemic applications. © 2014 Wiley Periodicals, Inc.

Direct Laser Ablation and Ionization of Solids for Chemical Analysis by Mass Spectrometry

Energy Technology Data Exchange (ETDEWEB)

Holt, J K; Nelson, E J; Klunder, G L [Forensic Science Center, Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States)

2007-04-15

A laser ablation/ionization mass spectrometer system is described for the direct chemical analysis of solids. An Nd:YAG laser is used for ablation and ionization of the sample in a quadrupole ion trap operated in an ion-storage (IS) mode that is coupled with a reflectron time-of-flight mass spectrometer (TOF-MS). Single pulse experiments have demonstrated simultaneous detection of up to 14 elements present in glasses in the ppm range. However, detection of the components has produced non-stoichiometric results due to difference in ionization potentials and fractionation effects. Time-of-flight secondary ionization mass spectrometry (TOF-SIMS) was used to spatially map elemental species on the surface and provide further evidence of fractionation effects. Resolution (m/{delta}m) of 1500 and detection limits of approximately 10 pg have been achieved with a single laser pulse. The system configuration and related operating principles for accurately measuring low concentrations of isotopes are described.

Volume fraction dependence of transient absorption signal and nonlinearities in metal nanocolloids

International Nuclear Information System (INIS)

Jayabalan, J; Singh, Asha; Khan, Salahuddin; Chari, Rama

2013-01-01

Electron–lattice thermalization dynamics in metal nanoparticles or in bulk metal is usually estimated by measuring the decay time of the change in transmission following an optical excitation. Such measurements can be performed in transient absorption geometry using a femtosecond laser. We find that for silver nanoplatelet/water colloids, the decay time of the transient absorption depends on the volume fraction of silver in water. By estimating the volume fraction dependence of nonlinearities in the same samples, we show that the variation in the measured decay time is due to pump-depletion effects present in the sample. The correct correction factor for taking into account pump-depletion effects in fifth- and higher-order nonlinearities is also presented. (paper)

Fractional vector calculus for fractional advection dispersion

Science.gov (United States)

Meerschaert, Mark M.; Mortensen, Jeff; Wheatcraft, Stephen W.

2006-07-01

We develop the basic tools of fractional vector calculus including a fractional derivative version of the gradient, divergence, and curl, and a fractional divergence theorem and Stokes theorem. These basic tools are then applied to provide a physical explanation for the fractional advection-dispersion equation for flow in heterogeneous porous media.

Erosion and corrosion resistance of laser cladded AISI 420 stainless steel reinforced with VC

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhe [Center for Laser-aided Manufacturing, Lyle School of Engineering, Southern Methodist University, 3101 Dyer Street, Dallas, TX 75206 (United States); Yu, Ting [Center for Laser-aided Manufacturing, Lyle School of Engineering, Southern Methodist University, 3101 Dyer Street, Dallas, TX 75206 (United States); School of Mechanical and Electrical Engineering, Nanchang University, Nanchang, Jiangxi 330031 (China); Kovacevic, Radovan, E-mail: kovacevi@smu.edu [Center for Laser-aided Manufacturing, Lyle School of Engineering, Southern Methodist University, 3101 Dyer Street, Dallas, TX 75206 (United States)

2017-07-15

Highlights: • The coatings of 420 stainless steel reinforced with VC were fabricated by high power direct diode laser. • The erosion resistance of the cladded layer was increased with the increase in the VC fraction. • No obvious improvement of erosion resistance was observed when the VC fraction was above 30 wt.%. • The corrosion resistance of the cladded layer was decreased with the increase in the VC fraction. - Abstract: Metal Matrix Composites (MMC) fabricated by the laser cladding process have been widely applied as protective coatings in industries to improve the wear, erosion, and corrosion resistance of components and prolong their service life. In this study, the AISI 420/VC metal matrix composites with different weight percentage (0 wt.%–40 wt.%) of Vanadium Carbide (VC) were fabricated on a mild steel A36 by a high power direct diode laser. An induction heater was used to preheat the substrate in order to avoid cracks during the cladding process. The effect of carbide content on the microstructure, elements distribution, phases, and microhardness was investigated in detail. The erosion resistance of the coatings was tested by using the abrasive waterjet (AWJ) cutting machine. The corrosion resistance of the coatings was studied utilizing potentiodynamic polarization. The results showed that the surface roughness and crack susceptibility of the laser cladded layer were increased with the increase in VC fraction. The volume fraction of the precipitated carbides was increased with the increase in the VC content. The phases of the coating without VC consisted of martensite and austenite. New phases such as precipitated VC, V{sub 8}C{sub 7}, M{sub 7}C{sub 3}, and M{sub 23}C{sub 6} were formed when the primary VC was added. The microhardness of the clads was increased with the increase in VC. The erosion resistance of the cladded layer was improved after the introduction of VC. The erosion resistance was increased with the increase in the VC content

Improvement of the quality of laser-wakefield accelerators: towards a compact free-electron laser

International Nuclear Information System (INIS)

Lehe, R.

2014-01-01

When an intense and short laser pulse propagates through an underdense gas, it can accelerate a fraction of the electrons of the gas, and thereby generate an electron bunch with an energy of a few hundreds of MeV. This phenomenon, which is referred to as laser-wakefield acceleration, has many potential applications, including the design of ultra-bright X-ray sources known as free electron lasers (FEL). However, these applications require the electron bunch to have an excellent quality (low divergence, emittance and energy spread). In this thesis, different solutions to improve the quality of the electron bunch are developed, both analytically and through the use of Particle-In-Cell (PIC) simulations. It is first shown however that PIC simulations tend to erroneously overestimate the emittance of the bunch, due to the numerical Cherenkov effect. Thus, in order to correctly estimate the emittance, a modified PIC algorithm is proposed, which is not subject to this unphysical Cherenkov effect. Using this algorithm, we have observed and studied a new mechanism to generate the electron bunch: optical transverse injection. This mechanism can produce bunches with a high charge, a low emittance and a low energy spread. In addition, we also proposed an experimental setup - the laser-plasma lens - which can strongly reduce the final divergence of the bunch. Finally, these results are put into context by discussing the properties required for the design of a compact FEL. It is shown in particular that laser-wakefield accelerator could be advantageously combined with innovative laser-plasma undulators, in order to produce bright X-rays sources. (author)

Influence of size and volume fraction of SiC particulates on properties of ex situ reinforced Al-4.5Cu-3Mg metal matrix composite prepared by direct metal laser sintering process

Energy Technology Data Exchange (ETDEWEB)

Ghosh, Subrata Kumar [Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Midnapore (West), Kharagpur 721302, West Bengal (India); Saha, Partha, E-mail: psaha@mech.iitkgp.ernet.in [Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Midnapore (West), Kharagpur 721302, West Bengal (India); Kishore, Shyam [Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Midnapore (West), Kharagpur 721302, West Bengal (India)

2010-07-15

Direct metal laser sintering (DMLS) process has a great potential to prepare metal matrix composites (MMCs) in fabrication of arbitrary shaped jobs through rapid manufacturing. In the present work, silicon carbide particulates reinforced aluminium based metal matrix composite was developed by direct metal laser sintering process. Influences of SiC particulate (SiCp) on density, porosity and microhardness of the composite were investigated. It shows that SiCp having 300 mesh size provides higher density and lower porosity because of lower clustering effect. Higher microhardness was achieved at 1200 mesh of reinforcement because of lower grain size. Microhardness increases with increase of volume fraction of SiCp and higher value was achieved at high reinforcement content of 30 vol.%. Microstructure was studied through scanning electron microscopy (SEM) and X-ray elemental mapping. Interfacial microstructure was also investigated and cracks were found in number of cases due to difference between co-efficient of thermal expansion of matrix alloy and SiCp.

Influence of size and volume fraction of SiC particulates on properties of ex situ reinforced Al-4.5Cu-3Mg metal matrix composite prepared by direct metal laser sintering process

International Nuclear Information System (INIS)

Ghosh, Subrata Kumar; Saha, Partha; Kishore, Shyam

2010-01-01

Direct metal laser sintering (DMLS) process has a great potential to prepare metal matrix composites (MMCs) in fabrication of arbitrary shaped jobs through rapid manufacturing. In the present work, silicon carbide particulates reinforced aluminium based metal matrix composite was developed by direct metal laser sintering process. Influences of SiC particulate (SiCp) on density, porosity and microhardness of the composite were investigated. It shows that SiCp having 300 mesh size provides higher density and lower porosity because of lower clustering effect. Higher microhardness was achieved at 1200 mesh of reinforcement because of lower grain size. Microhardness increases with increase of volume fraction of SiCp and higher value was achieved at high reinforcement content of 30 vol.%. Microstructure was studied through scanning electron microscopy (SEM) and X-ray elemental mapping. Interfacial microstructure was also investigated and cracks were found in number of cases due to difference between co-efficient of thermal expansion of matrix alloy and SiCp.

Characterization of laser ablation of copper in the irradiance regime of laser-induced breakdown spectroscopy analysis

Energy Technology Data Exchange (ETDEWEB)

Picard, J., E-mail: jessica.picard@cea.fr [Commissariat à l' Energie Atomique, DAM, Valduc, F-21120 Is-sur-Tille (France); Sirven, J.-B.; Lacour, J.-L. [Commissariat à l' Energie Atomique, DEN/DANS/DPC/SEARS/LANIE, Saclay, F-91191 Gif-sur-Yvette (France); Musset, O. [Université de Bourgogne, Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR CNRS 5209, F-21000 Dijon (France); Cardona, D.; Hubinois, J.-C. [Commissariat à l' Energie Atomique, DAM, Valduc, F-21120 Is-sur-Tille (France); Mauchien, P. [Commissariat à l' Energie Atomique, DEN/DANS/DPC/SEARS/LANIE, Saclay, F-91191 Gif-sur-Yvette (France)

2014-11-01

The LIBS signal depends both on the ablated mass and on the plasma excitation temperature. These fundamental parameters depend in a complex manner on laser ablation and on laser–plasma coupling. As several works in the literature suggest that laser ablation processes play a predominant role compared to plasma heating phenomena in the LIBS signal variations, this paper focuses on the study of laser ablation. The objective was to determine an interaction regime enabling to maximally control the laser ablation. Nanosecond laser ablation of copper at 266 nm was characterized by scanning electron microscopy and optical profilometry analysis, in air at 1 bar and in the vacuum. The laser beam spatial profile at the sample surface was characterized in order to give realistic values of the irradiance. The effect of the number of accumulated laser shots on the crater volume was studied. Then, the ablation crater morphology, volume, depth and diameter were measured as a function of irradiance between 0.35 and 96 GW/cm². Results show that in the vacuum, a regular trend is observed over the whole irradiance range. In air at 1 bar, below a certain irradiance, laser ablation is very similar to the vacuum case, and the ablation efficiency of copper was estimated at 0.15 ± 0.03 atom/photon. Beyond this irradiance, the laser beam propagation is strongly disrupted by the expansion of the dense plasma, and plasma shielding appears. The fraction of laser energy used for laser ablation and for plasma heating is estimated in the different irradiance regimes. - Highlights: • The morphology of copper's craters was studied as a function of the pulse energy. • Correlation at low energy and two pressures between crater volume and pulse energy • The ablation efficiency of copper at 1 bar is equal to 0.15 atom/photon. • Ablation efficiency in the vacuum is not limited by laser–plasma interaction. • Physical mechanisms of laser ablation at both pressures are discussed.

Randomized, Split-Face/Décolleté Comparative Trial of Procedure Enhancement System for Fractional non-Ablative Laser Resurfacing Treatment.

Science.gov (United States)

Robinson, Deanne Mraz; Frulla, Ashton P

2017-07-01

INTRODUCTION: A topical proprietary procedural enhancement system (PES) containing a combination of active ingredients including a tripeptide and hexapeptide (TriHex Technology™, Alastin Procedure Enhancement Invasive System, ALASTIN Skincare™, Inc., Carlsbad, CA) has been used successfully to aid in healing and improve symptomatology following resurfacing procedures. METHODS: PES (Gentle Cleanser, Regenerating Skin Nectar with TriHex Technology™, Ultra Nourishing Moisturizer with TriHex Technology™, Soothe + Protect Recovery Balm, Broad Spectrum 30+ Sunscreen) was compared to a basic regimen (Aquaphor™, Cerave™ cleanser, Vanicream™, Alastin Broad Spectrum 30+ Sunscreen) in a split face/ décolleté trial following fractional non-ablative thulium-doped resurfacing treatment to the face or décolleté. The skin was pre-conditioned and treated during and after the procedure using the two regimens. RESULTS: A blinded investigator rated the PES statistically superior to the basic regimen on healing post-laser treatment on day 4 based on lentigines, texture, and Global Skin Quality. Subjects also reported 'better looking and feeling' skin on the PES side. CONCLUSION: PES appears to improve healing post-non ablative thulium-doped resurfacing treatment to the face/décolleté in comparison with standard of care. J Drugs Dermatol. 2017;16(7):707-710..

Tissue responses to postoperative laser therapy in diabetic rats submitted to excisional wounds.

Directory of Open Access Journals (Sweden)

Cristiano de Loura Santana

Full Text Available In a previous study about low-level laser therapy biomodulation on a full-thickness burn model we showed that single and fractionated dose regimens increased wound healing and leukocyte influx similarly when compared with untreated control. In order to verify if this finding would be similar in an impaired wound model, we investigated the effect of single and multiple irradiations on wound closure rate, type of inflammatory infiltrate, myofibroblasts, collagen deposition, and optical retardation of collagen in diabetic rats. Female Wistar rats in the same estrous cycle had diabetes induced with streptozotocin and an 8-mm excisional wound performed with a punch. The experimental groups were: control group--untreated ulcer; single-dose group--ulcer submitted to single dose of diode laser therapy (λ = 660 ± 2 nm; P = 30 mW; energy density: 4 J/cm2 and fractionated-dose group--ulcer submitted to 1 J/cm2 laser therapy on Days 1, 3, 8, and 10. The ulcers were photographed on the experimental days and after euthanasia tissue samples were routinely processed for histological and immunohistochemistry analyses. Independently of the energy density, laser therapy accelerated wound closure by approximately 40% in the first three days in comparison to the control group. Laser therapy increased acute inflammatory infiltrate until Day 3. Both laser groups exhibited more myofibroblasts and better collagen organization than the control group. The findings demonstrate that low-level laser therapy in the immediate postoperative period can enhance the tissue repair process in a diabetes model. Similar effects were achieved with laser therapy applied a single time with an energy density of 4 J/cm2 and applied four times with an energy density of 1 J/cm2. The application of laser therapy in the inflammatory phase was the most important factor to the enhancement of the tissue repair process.

Spectroscopic analysis of femtosecond laser-induced gas breakdown

International Nuclear Information System (INIS)

Hermann, J.; Bruneau, S.; Sentis, M.

2004-01-01

The plasma generated by the interaction of a femtosecond laser pulse with gas has been analyzed using time- and space-resolved emission spectroscopy. The laser beam has been focused with a microscope objective into different gases (air, Ar, He) at pressures ranging from 10 2 to 10 5 Pa. From the analysis of spectral line emission from ions and neutral atoms, the plasma parameters and the plasma composition have been determined as a function of time and space. Furthermore, the generation of fast electrons and/or VUV radiation by the femtosecond laser interaction with the gas was brought to the fore. From the time- and space-evolution of the plasma parameters, a rough estimation of initial values of electron density and refraction index in the focal volume has been performed. These results are compared to analysis of the laser beam transmitted by the plasma. The latter show that only a small fraction of the laser energy is absorbed by the plasma while the spatial distribution of the transmitted laser beam is strongly perturbed by the plasma, which acts like a defocusing lens. However, in ambient helium, the plasma defocusing is weak due to the high ionization potential of helium. The understanding of femtosecond laser-induced gas breakdown is useful for process optimization in femtosecond laser applications like micromachining or surface microanalysis, etc

Fractional vector calculus and fractional Maxwell's equations

International Nuclear Information System (INIS)

Tarasov, Vasily E.

2008-01-01

The theory of derivatives and integrals of non-integer order goes back to Leibniz, Liouville, Grunwald, Letnikov and Riemann. The history of fractional vector calculus (FVC) has only 10 years. The main approaches to formulate a FVC, which are used in the physics during the past few years, will be briefly described in this paper. We solve some problems of consistent formulations of FVC by using a fractional generalization of the Fundamental Theorem of Calculus. We define the differential and integral vector operations. The fractional Green's, Stokes' and Gauss's theorems are formulated. The proofs of these theorems are realized for simplest regions. A fractional generalization of exterior differential calculus of differential forms is discussed. Fractional nonlocal Maxwell's equations and the corresponding fractional wave equations are considered

Optical timing receiver for the NASA laser ranging system. Part I. Constant-fraction discriminator

International Nuclear Information System (INIS)

Leskovar, B.; Lo, C.C.

1975-01-01

Position-resolution capabilities of the NASA laser ranging system are essentially determined by time-resolution capabilities of its optical timing receiver. The optical timing receiver consists of a fast photoelectric device, primarily a standard of microchannel-plate-type photomultiplier or an avalanche photodiode detector, a timing discriminator, a high-precision time-interval digitizer, and a signal-processing system. The time-resolution capabilities of the receiver are determined by the photoelectron time spread of the photoelectric device, the time walk and resolution characteristics of the timing discriminator, and the time-interval digitizer. It is thus necessary to evaluate available fast photoelectronic devices with respect to their time-resolution capabilities, and to design a very low time walk timing discriminator and a high-precision time digitizer which will be used in the laser ranging system receiver. (auth)

Fractional Number Operator and Associated Fractional Diffusion Equations

Science.gov (United States)

Rguigui, Hafedh

2018-03-01

In this paper, we study the fractional number operator as an analog of the finite-dimensional fractional Laplacian. An important relation with the Ornstein-Uhlenbeck process is given. Using a semigroup approach, the solution of the Cauchy problem associated to the fractional number operator is presented. By means of the Mittag-Leffler function and the Laplace transform, we give the solution of the Caputo time fractional diffusion equation and Riemann-Liouville time fractional diffusion equation in infinite dimensions associated to the fractional number operator.

Matrix Assisted Pulsed Laser Evaporation for growth of fullerene thin films

DEFF Research Database (Denmark)

Canulescu, Stela; Schou, Jørgen; Fæster Nielsen, Søren

C60 fullerene thin films of average thickness of more than 100 nm can be produced in vacuum by matrix-assisted pulsed laser evaporation (MAPLE). A 355 nm Nd:YAG laser was directed onto a frozen target of anisole with a concentration of 0.67 wt% C60. At laser fluences below 1.5 J/cm2, a dominant...... fraction of the film molecules are C60 transferred to the substrate without any fragmentation. Highresolution SEM images of MAPLE deposited films reveal large circular droplets on the surface with high amount of material concentrated at edges (Fig. 1A). These features, observed over a wide range of laser...... fluences, are caused by ejection of large matrix-fullerene liquid droplets into the gas-phase and subsequent deposition. At similar laser energies, but using an unfocused laser beam, MAPLE favours evaporation of matrix and organic molecules, resulting in production of films with smooth surfaces and minimal...

Fractional Processes and Fractional-Order Signal Processing Techniques and Applications

CERN Document Server

Sheng, Hu; Qiu, TianShuang

2012-01-01

Fractional processes are widely found in science, technology and engineering systems. In Fractional Processes and Fractional-order Signal Processing, some complex random signals, characterized by the presence of a heavy-tailed distribution or non-negligible dependence between distant observations (local and long memory), are introduced and examined from the ‘fractional’ perspective using simulation, fractional-order modeling and filtering and realization of fractional-order systems. These fractional-order signal processing (FOSP) techniques are based on fractional calculus, the fractional Fourier transform and fractional lower-order moments. Fractional Processes and Fractional-order Signal Processing: • presents fractional processes of fixed, variable and distributed order studied as the output of fractional-order differential systems; • introduces FOSP techniques and the fractional signals and fractional systems point of view; • details real-world-application examples of FOSP techniques to demonstr...

Laser-driven particle acceleration for radiobiology and radiotherapy: where we are and where we are going

Science.gov (United States)

Giulietti, Antonio

2017-05-01

Radiation therapy of tumors progresses continuously and so do devices, sharing a global market of about $ 4 billions, growing at an annual rate exceeding 5%. Most of the progress involves tumor targeting, multi-beam irradiation, reduction of damage on healthy tissues and critical organs, dose fractioning. This fast-evolving scenario is the moving benchmark for the progress of the laser-based accelerators towards clinical uses. As for electrons, both energy and dose requested by radiotherapy are available with plasma accelerators driven by lasers in the power range of tens of TW but several issues have still to be faced before getting a prototype device for clinical tests. They include capability of varying electron energy, stability of the process, reliability for medical users. On the other side hadron therapy, presently applied to a small fraction of cases but within an exponential growth, is a primary option for the future. With such a strong motivation, research on laser-based proton/ion acceleration has been supported in the last decade in order to get performances suitable to clinical standards. None of these performances has been achieved so far with laser techniques. In the meantime a rich crop of data have been obtained in radiobiological experiments performed with beams of particles produced with laser techniques. It is quite significant however that most of the experiments have been performed moving bio samples to laser labs, rather moving laser equipment to bio labs or clinical contexts. This give us the measure that laser community cannot so far provide practical devices usable by non-laser people.

Summary of the laser working group

International Nuclear Information System (INIS)

Bigio, I.J.; Kurnit, N.A.; Donaldson, W.R.; Srinivasan-Rao, T.

1988-10-01

The laser working group considered several options to deliver synchronized laser pulses of the required energy to the photocathode and laser triggered switches. These requirements actually decreased during the course of the workshop, and the values finally settled upon (<10 μJ in 100 fs at ∼250 nm for the photocathode and ∼20 mJ in 2 ps near either 250 nm or 1 μm for the switches) were considered to be well within the state of the art. Some development work may be required, however, to provide a system that has the desirable characteristics of stability, ease of use and low maintenance. The baseline concept, which is similar to a number of existing systems, utilizes doubled Nd:YAG-pumped dye oscillator/amplifiers to produce an upconverted picosecond pulse that can be amplified to tens of mJ in a KrF excimer laser. A fraction of the dye oscillator output is also compressed by means of a fiber-grating compressor and further amplified in a dye amplifier before being upconverted to produce the synchronized pulse for the photocathode. 9 refs., 1 fig

Light-material interactions in laser material processing

International Nuclear Information System (INIS)

Chiang, S.; Albright, C.E.

1989-01-01

The authors discusses how light interactions with materials in laser material processing operations occur by a variety of mechanisms depending on the material being processed, the wavelength of the laser light, the gaseous environment, and the physical state of the material surface. The high reflectivity of metals limits the fraction of the beam power absorbed by the solid metal surface. For metals in the solid state, reflectivity increases as the wavelength of the laser light and the electrical conductivity of the metal increase. The reflectivity of metals is reduced upon heating to the melting point, and further reduced upon melting. At high power densities the liquid metal surface is heated so quickly that very rapid vaporization occurs. The recoil force produced by the evaporation causes a depression in the liquid/vapor interface. The keyhole resulting from this depression allows for multiple reflections and thus increases beam absorption in the liquid

The effect of powder composition on the morphology of in situ TiC composite coating deposited by Laser-Assisted Powder Deposition (LAPD)

International Nuclear Information System (INIS)

Emamian, Ali; Corbin, Stephen F.; Khajepour, Amir

2012-01-01

Highlights: ► The novel idea was to develop Fe-TiC containing high volume fraction of TiC. ► Increased TiC volume fraction enhanced clad hardness profile. ► Both, laser conditions and fed powder compositions affected the clad microstructure. ► Hardness and TiC volume fraction was maximized by control over melt pool composition. ► Hardness/TiC volume fraction was maximized by controlling of laser parameters. - Abstract: In this paper, the effect of powder composition on in situ TiC formation within an Fe-based matrix coating during laser cladding was studied. Different atomic ratios of C:Ti (45% and 55%) were selected in order to adjust the matrix from an Fe-Ti-based composition to an Fe-C-based one. Fe percentages of 70, 60, 50 and 10 wt% were explored to increase the volume fraction of TiC in the clad. Results showed that chemical composition affects the TiC morphology as well as the TiC distribution and hardness profile in the clad. By increasing the C:Ti ratio from 45 at% to 55 at%, the volume fraction of the formed TiC increases. A higher volume fraction of TiC in the clad resulted in increases clad hardness. SEM and EDS analyses were used to characterize the phases in the clad, while increasing the C ratio promoted the formation of excess graphite in the Fe matrix.

The effect of powder composition on the morphology of in situ TiC composite coating deposited by Laser-Assisted Powder Deposition (LAPD)

Energy Technology Data Exchange (ETDEWEB)

Emamian, Ali, E-mail: aemamian@uwaterloo.ca [Research Associate and Postdoctoral fellow in the Department of Mechanics and Mechatronics, University of Waterloo, 200 University West, Waterloo, N2L 4 3G1 (Canada); Corbin, Stephen F. [Professor and Canada Research Chair in the Department of Civil and Resource Engineering, Dalhousie University, Halifax, Nova Scotia, P.O. Box 15000, B3H 5 4R2 (Canada); Khajepour, Amir [Professor and Canada Research Chair in the Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo (Canada)

2012-11-15

Highlights: Black-Right-Pointing-Pointer The novel idea was to develop Fe-TiC containing high volume fraction of TiC. Black-Right-Pointing-Pointer Increased TiC volume fraction enhanced clad hardness profile. Black-Right-Pointing-Pointer Both, laser conditions and fed powder compositions affected the clad microstructure. Black-Right-Pointing-Pointer Hardness and TiC volume fraction was maximized by control over melt pool composition. Black-Right-Pointing-Pointer Hardness/TiC volume fraction was maximized by controlling of laser parameters. - Abstract: In this paper, the effect of powder composition on in situ TiC formation within an Fe-based matrix coating during laser cladding was studied. Different atomic ratios of C:Ti (45% and 55%) were selected in order to adjust the matrix from an Fe-Ti-based composition to an Fe-C-based one. Fe percentages of 70, 60, 50 and 10 wt% were explored to increase the volume fraction of TiC in the clad. Results showed that chemical composition affects the TiC morphology as well as the TiC distribution and hardness profile in the clad. By increasing the C:Ti ratio from 45 at% to 55 at%, the volume fraction of the formed TiC increases. A higher volume fraction of TiC in the clad resulted in increases clad hardness. SEM and EDS analyses were used to characterize the phases in the clad, while increasing the C ratio promoted the formation of excess graphite in the Fe matrix.

Delivery and reveal of localization of upconversion luminescent microparticles and quantum dots in the skin in vivo by fractional laser microablation, multimodal imaging, and optical clearing

Science.gov (United States)

Volkova, Elena K.; Yanina, Irina Yu; Genina, Elina A.; Bashkatov, Alexey N.; Konyukhova, Julia G.; Popov, Alexey P.; Speranskaya, Elena S.; Bucharskaya, Alla B.; Navolokin, Nikita A.; Goryacheva, Irina Yu.; Kochubey, Vyacheslav I.; Sukhorukov, Gleb B.; Meglinski, Igor V.; Tuchin, Valery V.

2018-02-01

Delivery and spatial localization of upconversion luminescent microparticles [Y2O3:Yb, Er] (mean size ˜1.6 μm) and quantum dots (QDs) (CuInS2/ZnS nanoparticles coated with polyethylene glycol-based amphiphilic polymer, mean size ˜20 nm) inside rat skin was studied in vivo using a multimodal optical imaging approach. The particles were embedded into the skin dermis to the depth from 300 to 500 μm through microchannels performed by fractional laser microablation. Low-frequency ultrasound was applied to enhance penetration of the particles into the skin. Visualization of the particles was revealed using a combination of luminescent spectroscopy, optical coherence tomography, confocal microscopy, and histochemical analysis. Optical clearing was used to enhance the image contrast of the luminescent signal from the particles. It was demonstrated that the penetration depth of particles depends on their size, resulting in a different detection time interval (days) of the luminescent signal from microparticles and QDs inside the rat skin in vivo. We show that luminescent signal from the upconversion microparticles and QDs was detected after the particle delivery into the rat skin in vivo during eighth and fourth days, respectively. We hypothesize that the upconversion microparticles have created a long-time depot localized in the laser-created channels, as the QDs spread over the surrounding tissues.

Clinical effect of ablative fractional laser-assisted topical anesthesia on human skin%点阵Er:YAG激光辅助外用麻醉药物传输的临床观察

Institute of Scientific and Technical Information of China (English)

罗瑶佳; 吴严; 高兴华; 何春涤; 陈洪铎; 李远宏

2011-01-01

Objective Most topically used medications need a long time to be absorbed into the skin owing to the stratum corneum(SC) barrier. The fractional Erbium:yttrium-aluminum-garnet (Er:YAG) laser,creating vertical channels to disrupt the SC,might assist the delivery of topically applied drug to penetrate into the skin. This study was intended to determine whether pretreatment with fractional Er:YAG laser could assist transdermal delivery of topical anesthesia. Methods Thirty-one subjects were enrolled in this study. Three neighboring 4cm×3cm regions were marked on their left forearm with the interference of Er:YAG laser plus topical anesthesia (laser +anesthesia +pain stimuli), anesthesia control (anesthesia + pain stimuli) and blank control (moisture + pain stimuli) respectively. Then each region was treated with YSGG laser to evaluate the pain sensation using the visual analogue scale (VAS) as a way to scale the transdermal absorption of topical anesthesia. Results The pain scores for Er:YAG laser plus topical anesthesia, anesthesia control and blank control regions are 2.84±0.66, 3.91 ±0.79 and 4.59±0.87 respectively. The pain score for Er:YAG laser plus topical anesthesia region is significantly lower than the anesthesia control (P=0.042) and blank control (P=0.003). Conclusion This proved the laser assistance of transdermal absorption for topical anesthesia medication.%目的:由于角质层的屏障作用,外用药物很难经皮吸收.铒:钇铝石榴石(Er:YAG)点阵激光通过点状剥脱的模式穿透角质层,破坏了角质层的完整性,可以加速外用药物经皮吸收的速度.本实验旨在验证外用表面麻醉药之前用点阵Er:YAG激光破坏角质层,可以促进表面麻醉药的吸收速度.方法:在31名受试者的左前臂上划出三块相邻的4cm×3cm区域,分别予以Er:YAG激光加表面麻醉药("点阵+麻药+疼痛"),�

Studies of the Influence of Beam Profile and Cooling Conditions on the Laser Deposition of a Directionally-Solidified Superalloy

Directory of Open Access Journals (Sweden)

Shuo Yang

2018-02-01

Full Text Available In the laser deposition of single crystal and directionally-solidified superalloys, it is desired to form laser deposits with high volume fractions of columnar grains by suppressing the columnar-to-equiaxed transition efficiently. In this paper, the influence of beam profile (circular and square shapes and cooling conditions (natural cooling and forced cooling on the geometric morphology and microstructure of deposits were experimentally studied in the laser deposition of a directionally-solidified superalloy, IC10, and the mechanisms of influence were revealed through a numerical simulation of the thermal processes during laser deposition. The results show that wider and thinner deposits were obtained with the square laser beam than those with the circular laser beam, regardless of whether natural or forced cooling conditions was used. The heights and contact angles of deposits were notably increased due to the reduced substrate temperatures by the application of forced cooling for both laser beam profiles. Under natural cooling conditions, columnar grains formed epitaxially at both the center and the edges of the deposits with the square laser beam, but only at the center of the deposits with the circular laser beam; under forced cooling conditions, columnar grains formed at both the center and the edges of deposits regardless of the laser beam profile. The high ratios of thermal gradient and solidification velocity in the height direction of the deposits were favorable to forming deposits with higher volume fractions of columnar grains.

Resonant laser techniques for combustion and flow diagnostics

Energy Technology Data Exchange (ETDEWEB)

Fritzon, Rolf

1998-05-01

This thesis presents results from two areas of research. Firstly, the resonant coherent laser techniques polarization spectroscopy (PS), degenerate four-wave mixing (DFWM) and stimulated emission (SE) have been developed in the general field of combustion diagnostics. Secondly, laser induced fluorescence (LIF) has been developed and applied for the visualization of mixture fractions in turbulent non reacting flows. PS was developed for instantaneous two-dimensional imaging of minor species in flames, the technique being demonstrated on OH and NO. Various aspects of imaging and of detection in general were investigated. Two-photon induced PS was demonstrated for the detection of NH{sub 3}, CO and N{sub 2} molecules. LIF was monitored simultaneously to allow a quantitative comparison between the techniques. Furthermore, PS and DFWM were developed for instantaneous two-dimensional OH temperature imaging. Through a novel experimental approach based on the use of a dual-wavelength dye laser and a diffraction grating the temperature imaging measurements were performed using only one laser and one CCD camera. A comparison between the two techniques was made. SE was through a crossed-beam arrangement developed for spatially resolved detection of flame species. Two-dimensional LIF was developed and applied for measuring mixture fractions in the shear layer between two co-flowing turbulent gaseous jets. The technique was further applied in a study of the mixing of a turbulent water jet impinging orthogonally onto a flat surface. Average concentration fields in the center-plane of the jet was compared with results from large eddy simulations and with data from the literature 221 refs, 48 figs, 5 tabs

Series expansion in fractional calculus and fractional differential equations

OpenAIRE

Li, Ming-Fan; Ren, Ji-Rong; Zhu, Tao

2009-01-01

Fractional calculus is the calculus of differentiation and integration of non-integer orders. In a recently paper (Annals of Physics 323 (2008) 2756-2778), the Fundamental Theorem of Fractional Calculus is highlighted. Based on this theorem, in this paper we introduce fractional series expansion method to fractional calculus. We define a kind of fractional Taylor series of an infinitely fractionally-differentiable function. Further, based on our definition we generalize hypergeometric functio...

UNS S32750 super duplex steel welding using pulsed Nd:YAG laser

International Nuclear Information System (INIS)

Francini, O.D.; Andrade, G.G.; Clemente, M.S.; Gallego, J.; Ventrella, V.A.

2016-01-01

Laser is a flexible and powerful tool with many relevant applications in industry, mainly in the welding area. Lasers today provide the welding industry technical solutions to many problems. This work studied the weld metal obtained by pulsed laser welding of Nd: YAG super duplex stainless steel UNS S32750 employed in the oil and natural gas, analyzing the influence of high cooling rate, due to the laser process, the swing phase ferrite / austenite. Were performed weld beads in butt joint with different repetition rates. The different microstructures were obtained by optical microscopy and scanning electron microscopy. The results showed that the effect of varying the welding energy of Nd: YAG laser on the volume fractions of the phases ferrite/austenite in the weld metal was its ferritization and low austenite amount on the grain boundary. (author)

Comparative analysis of the effects of CO2 fractional laser and sonophoresis on human skin penetration with 5-aminolevulinic acid.

Science.gov (United States)

Choi, J H; Shin, E J; Jeong, K H; Shin, M K

2017-11-01

Successful delivery of a photosensitizer into the skin is an important factor for effective photodynamic therapy (PDT). The effective method to increase drug penetration within short incubation time overcoming skin barrier have been investigated. This study was performed to analyze and compare the effectiveness of ablative fractional laser (FXL) pretreatment and/or sonophoresis for enhancing the penetration of 5-aminolevulinic acid (ALA) into human skin in vivo. Twenty-four identical 1 × 1 cm 2 treatment areas were mapped on the backs of ten healthy male subjects. Each area received FXL pretreatment and/or sonophoresis with different energy settings and ALA incubation times. After treatments, porphyrin fluorescence reflecting the ALA penetration were measured. Application of ablative CO 2 FXL pretreatment resulted to higher fluorescence intensities than the non-treatment group. Incubation times were positively correlated with the increments of ALA penetration. However, increasing pulse energy or combining with sonophoresis did not show additional positive effects on ALA penetration. Ablative CO 2 FXL pretreatment effectively facilitated ALA penetration in human skin in vivo. Ablative CO 2 FXL alone without sonophoresis setting pulse energy of 10 and 20 mJ with more than 60 min of ALA incubation time could be an ideal setting for ALA penetration.

Ion Production by Laser Impact on a Silver Surface

DEFF Research Database (Denmark)

Christensen, Bo Toftmann; Schou, Jørgen

Even at moderate fluence (0.6 -2.4 J/cm2) laser impact on metals in the UV regime results in a significant number of ions emitted from the surface. Even at this low fluence the particles ejected from a surface interact with each other in a so-called laser ablation plume. The ablated particles...... are largely neutrals at low fluence, but the fraction of ions increases strongly with fluence. We have irradiated silver in a vacuum chamber (~ 10-7 mbar) with a Nd:YAG laser at a wavelength of 355 nm. The ion flow in different directions has been measured with a hemispherical array of Langmuir probes...... range considered is also a typical range for pulsed laser deposition (PLD), by which the material is collected on a suitable substrate for thin film growth. PLD has the advantage compared with other film deposition methods, that even a complicated stoichiometry, e.g. metal oxides or alloys, can...

Fractional governing equations of transient groundwater flow in confined aquifers with multi-fractional dimensions in fractional time

Directory of Open Access Journals (Sweden)

M. L. Kavvas

2017-10-01

Full Text Available Using fractional calculus, a dimensionally consistent governing equation of transient, saturated groundwater flow in fractional time in a multi-fractional confined aquifer is developed. First, a dimensionally consistent continuity equation for transient saturated groundwater flow in fractional time and in a multi-fractional, multidimensional confined aquifer is developed. For the equation of water flux within a multi-fractional multidimensional confined aquifer, a dimensionally consistent equation is also developed. The governing equation of transient saturated groundwater flow in a multi-fractional, multidimensional confined aquifer in fractional time is then obtained by combining the fractional continuity and water flux equations. To illustrate the capability of the proposed governing equation of groundwater flow in a confined aquifer, a numerical application of the fractional governing equation to a confined aquifer groundwater flow problem was also performed.

Evaluating the safety and efficacy of the 1,440-nm laser in the treatment of photodamage in Asian skin.

Science.gov (United States)

Marmon, Shoshana; Shek, Samantha Y N; Yeung, C K; Chan, Nicola P Y; Chan, Johnny Cy; Chan, Henry H L

2014-07-01

As the demand for diminished procedure-associated downtime continues to increase, nonablative fractional laser resurfacing is becoming a more popular intervention in the progression of photoaging. Patients with pigmented skin and a mild degree of photodamage may be particularly suited for a less intensive laser treatment. In this study, we have evaluated the safety and efficacy of a low energy, low density 1,440-nm fractional laser in the treatment of multiple signs of photoaging including dyspigmentation, wrinkling, tissue laxity, enlarged pores, and skin roughness in Asians. Ten Chinese subjects with Fitzpatrick skin types III-V and visible signs of photodamage participated in this study. Patients received four treatments at 2-week intervals with a 1,440-nm diode-based fractional laser. Photographs were taken at baseline, 2 weeks after each of the first three treatments and 4 weeks after the final treatment. Images were evaluated independently by two physicians. Clinical improvement and adverse events were analyzed. Discomfort, heat sensation and overall patient satisfaction associated with the procedure were also quantified. In this prospective single-arm study, signs of photoaging were examined after treatment with the 1,440-nm laser. Here we show that a series of four treatments with this device produced a mild improvement in skin texture, pigmentation, and wrinkling. Changes in pore size and skin laxity failed to reach statistical significance. Immediate after-effects of the procedure included erythema and edema which were transient and left no permanent sequela. A significant proportion of patients reported some degree of discomfort during the procedure despite use of a topical anesthetic. One patient developed a discrete, localized area of post-inflammatory hyperpigmentation which completely resolved by the final follow up visit. The low energy, low density nonablative 1,440-nm fractional laser produces a mild improvement in select signs of photodamage

Ultraviolet SO lasers optically pumped by a tunable, line-narrowed KrF laser

International Nuclear Information System (INIS)

Stuart, B.C.D.

1992-06-01

The feasibility of an ultraviolet energy storage laser based on the long-lived sulfur monoxide A 3 π-χ 3 Σ - electronic transition was investigated, and an ultraviolet laser based on the short-lived SO(B 3 Σ - -χ 3 Σ - ) transition was demonstrated and modeled. Both were optically pumped by a continuously tunable, line-narrowed KrF laser developed for efficient rotationally resolved excitation of SO. SO was produced by both microwave discharge and excimer laser photolysis of the precursor molecules SO 2 and SOCl 2 , with a maximum SO concentration (10 16 cm -3 ) generated by ArF (193 nm) photodissociation of SO 2 . Laser induced fluorescence of SO was used to study the excitation spectroscopy, vibrational branching ratios, lifetimes and deactivation rates. The radiative lifetime of SO(A 3 π 2 ,v' = 5) was measured to be 6.9 μs and that of SO(B,v' = 1) to be 33 ns. Lifetimes in the highly perturbed SO(B,v' = 2) level ranged from 28--90 ns. Measurements and modeling of the excitation saturation fluence as a function of buffer gas pressure determined what fraction of the ground state SO(X) molecules could be excited to SO(A) or SO(B). No evidence of excited state absorption was seen. Lasing on six new ultraviolet SO(B-X) vibrational bands in the range 262--315 nm was demonstrated. SO(B-X) pulse energies of up to 11 μJ were obtained and the gain coefficient was estimated to be 0.1 cm -1 . A multi-level rate equation model of the SO(B-X) excitation and lasing transitions, including collisional rotational mixing, described the dynamics of the lasing and measured output very well. Modeling showed and experiments confirmed that the maximum possible SO laser gain simply corresponded to saturating the excitation of a single rotational level. Collisional coupling of the rotational levels increased the laser output energy

Comparison between Er:YAG laser and bipolar radiofrequency combined with infrared diode laser for the treatment of acne scars: Differential expression of fibrogenetic biomolecules may be associated with differences in efficacy between ablative and non-ablative laser treatment.

Science.gov (United States)

Min, Seonguk; Park, Seon Yong; Moon, Jungyoon; Kwon, Hyuck Hoon; Yoon, Ji Young; Suh, Dae Hun

2017-04-01

Fractional Er:YAG minimizes the risk associated with skin ablation. Infrared diode laser and radiofrequency have suggested comparable improvements in acne scar. We compared the clinical efficacy of Er:YAG laser and bipolar radiofrequency combined with diode laser (BRDL) for the treatment of acne scars. Moreover, acute molecular changes of cytokine profile associated with wound healing have been evaluated to suggest mechanisms of improvement of acne scar. Twenty-four subjects with mild-to-moderate acne scars were treated in a split-face manner with Er:YAG and BRDL, with two treatment sessions, 4 weeks apart. Objective and subjective assessments were done at baseline, 1, 3, 7 days after each treatment and 4 weeks after last treatment. Skin biopsy specimens were obtained at baseline, 1, 3, 7, 28 days after one session of treatment for investigation of molecular profile of acute skin changes by laser treatment. Investigator's Global Assessment representing the improvement degree shows 2.1 (50%) in fractional Er:YAG and 1.2 (25%) in BRDL. Er:YAG induced the later and higher peak expression of TGFβs and collagenases, whereas BRDL induced earlier and lower expression of TGFβ and collagenases, relatively. PPARγ dropped rapidly after a peak in Er:YAG-treated side, which is associated with tissue inhibitor of metalloproteinase (TIMP) expression. We observed higher expression of TIMP after Er:YAG treatment compared with BRDL by immunohistochemistry, which may be associated with the expression of upregulation of collagen fibers. The superior efficacy of Er:YAG to BRDL in the treatment of acne scars may be associated with higher expression of collagen which is associated with differential expression of TGFβs, collagenases, PPARγ, and TIMP. Lasers Surg. Med. 49:341-347, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Laser-induced transfer of gel microdroplets for cell printing

Science.gov (United States)

Yusupov, V. I.; Zhigar'kov, V. S.; Churbanova, E. S.; Chutko, E. A.; Evlashin, S. A.; Gorlenko, M. V.; Cheptsov, V. S.; Minaev, N. V.; Bagratashvili, V. N.

2017-12-01

We study thermal and transport processes involved in the transfer of gel microdroplets under the conditions of laser cell microprinting. The specific features of the interaction of pulsed laser radiation ( λ = 1.064 µm, pulse duration 4 - 200 ns, energy 2 µJ - 1 mJ) with the absorbing gold film deposited on the glass donor substrate are determined. The investigation of the dynamics of transport processes by means of fast optical video recording and optoacoustic methods makes it possible to determine the characteristics of the produced gel jets as functions of the laser operation regimes. The hydrodynamic process of interaction between the laser radiation and the gold coating with the hydrogel layer on it is considered and the temperature in the region of the laser pulse action is estimated. It is shown that in the mechanism of laser-induced transfer a significant role is played by the processes of explosive boiling of water (in gel) and gold. The amount of gold nanoparticles arriving at the acceptor plate in the process of the laser transfer is determined. For the laser pulse duration 8 ns and small energies (less than 10 µJ), the fraction of gold nanoparticles in the gel microdroplets is negligibly small, and their quantity linearly grows with increasing pulse energy. The performed studies offer a base for optimising the processes of laser transfer of gel microdroplets in the rapidly developing technologies of cell microprinting.

DEVICE FOR MEASURING OF THERMAL LENS PARAMETERS IN LASER ACTIVE ELEMENTS WITH A PROBE BEAM METHOD

Directory of Open Access Journals (Sweden)

A. N. Zakharova

2015-01-01

Full Text Available We have developed a device for measuring of parameters of thermal lens (TL in laser active elements under longitudinal diode pumping. The measurements are based on the probe beam method. This device allows one to determine sign and optical power of the lens in the principal meridional planes, its sensitivity factor with respect to the absorbed pump power and astigmatism degree, fractional heat loading which make it possible to estimate integral impact of the photoelastic effect to the formation of TL in the laser element. The measurements are performed in a linearly polarized light at the wavelength of 532 nm. Pumping of the laser element is performed at 960 nm that makes it possible to study laser materials doped with Yb3+ and (Er3+, Yb3+ ions. The precision of measurements: for sensitivity factor of TL – 0,1 m-1/W, for astigmatism degree – 0,2 m-1/W, for fractional heat loading – 5 %, for the impact of the photoelastic effect – 0,5 × 10-6 K-1. This device is used for characterization of thermal lens in the laser active element from an yttrium vanadate crystal, Er3+,Yb3+:YVO .

Fractional governing equations of transient groundwater flow in confined aquifers with multi-fractional dimensions in fractional time

OpenAIRE

M. L. Kavvas; T. Tu; A. Ercan; J. Polsinelli

2017-01-01

Using fractional calculus, a dimensionally consistent governing equation of transient, saturated groundwater flow in fractional time in a multi-fractional confined aquifer is developed. First, a dimensionally consistent continuity equation for transient saturated groundwater flow in fractional time and in a multi-fractional, multidimensional confined aquifer is developed. For the equation of water flux within a multi-fractional multidimensional confined aquifer, a dimensionally...

Harmonic mode-locking and sub-round-trip time nonlinear dynamics of electro-optically controlled solid state laser

Science.gov (United States)

Gorbunkov, M. V.; Maslova, Yu Ya; Petukhov, V. A.; Semenov, M. A.; Shabalin, Yu V.; Tunkin, V. G.

2018-03-01

Harmonic mode-locking in a solid state laser due to optoelectronic control is studied numerically on the basis of two methods. The first one is detailed numeric simulation taking into account laser radiation fine time structure. It is shown that optimally chosen feedback delay leads to self-started mode-locking with generation of desired number of pulses in the laser cavity. The second method is based on discrete maps for short laser pulse energy. Both methods show that the application of combination of positive and negative feedback loops allows to reduce the period of regular nonlinear dynamics down to a fraction of a laser cavity round trip time.

Bonding structure and mechanical properties of B-C-N thin films synthesized by pulsed laser deposition at different laser fluences

International Nuclear Information System (INIS)

Wang, C.B.; Xiao, J.L.; Shen, Q.; Zhang, L.M.

2016-01-01

Boron carbon nitride (B-C-N) thin films have been grown by pulsed laser deposition under different laser fluences changing from 1.0 to 3.0 J/cm"2. The influence of laser fluence on microstructure, bonding structure, and mechanical properties of the films was studied, so as to explore the possibility of improving their mechanical properties by controlling bonding structure. The bonding structure identified by FT-IR and XPS indicated the coexistence of B-N, B-C, N-C and N=C bonds in the films, suggesting the formation of a ternary B-C-N hybridization. There is a clear evolution of bonding structure in the B-C-N films with the increasing of laser fluence. The variation of the mechanical properties as a function of laser fluence was also in accordance with the evolution of B-C and sp"3 N-C bonds whereas contrary to that of sp"2 B-N and N=C bonds. The hardness and modulus reached the maximum value of 33.7 GPa and 256 GPa, respectively, at a laser fluence of 3.0 J/cm"2, where the B-C-N thin films synthesized by pulsed laser deposition possessed the highest intensity of B-C and N-C bonds and the lowest fraction of B-N and N=C bonds. - Highlights: • Improvement of mechanical property by controlling bonding structure is explored. • A clear evolution of bonding structure with the increasing of laser fluence • Variation of property is in accordance with the evolution of B−C and N−C bonds.

Laser Mode Behavior of the Cassini CIRS Fourier Transform Spectrometer at Saturn

Science.gov (United States)

Brasunas, John C.

2012-01-01

The CIRS Fourier transform spectrometer aboard the NASA/ESA/ASI Cassini orbiter has been acquiring spectra of the Saturnian system since 2004. The CIRS reference interferometer employs a laser diode to trigger the interferogram sampling. Although the control of laser diode drive current and operating temperature are stringent enough to restrict laser wavelength variation to a small fraction of CIRS finest resolution element, the CIRS instrument does need to be restarted every year or two, at which time it may start in a new laser mode. By monitoring the Mylar absorption features in uncalibrated spectra due to the beam splitter Mylar substrate, it can be shown that these jumps are to adjacent modes and that most of the eight-year operation so far is restricted to three adjacent modes. For a given mode, the wavelength stability appears consistent with the stability of the laser diode drive curren.t and operating temperature.

Determination of the antiproton-to-electron mass ratio by precision laser spectroscopy of $\\overline{p}He^{+}$

CERN Document Server

Hori, M; Eades, John; Gomikawa, K; Hayano, R S; Ono, N; Pirkl, Werner; Widmann, E; Torii, H A; Juhász, B; Barna, D; Horváth, D

2006-01-01

A femtosecond optical frequency comb and continuous-wave pulse- amplified laser were used to measure 12 transition frequencies of antiprotonic helium to fractional precisions of (9-16) 10/sup -9lifetimes hitherto unaccessible to our precision laser spectroscopy method. Comparisons with three-body QED calculations yielded an antiproton-to-electron mass ratio of M/sub pmacron//m/sub e/=1836.152 674(5).

Holographic interferometry of isolated deuterium plasmas produced by a CO2 laser

International Nuclear Information System (INIS)

Gatenby, P.V.; Walker, A.C.

1978-10-01

The application of double exposure fractional fringe holographic interferometry to measurements of electron density in a plasma generated by irradiation of a freely falling pellet of solid deuterium with a focused CO 2 laser pulse is discussed. A particularly simple technique is used for processing and reconstructing the holograms and this is described in detail. A summary and discussion of the results is included with the emphasis on the observed evolution of the deuterium plasma over the duration of the laser irradiation. (author)

Injection of electrons by colliding laser pulses in a laser wakefield accelerator

Energy Technology Data Exchange (ETDEWEB)

Hansson, M., E-mail: martin.hansson@fysik.lth.se; Aurand, B.; Ekerfelt, H.; Persson, A.; Lundh, O.

2016-09-01

To improve the stability and reproducibility of laser wakefield accelerators and to allow for future applications, controlling the injection of electrons is of great importance. This allows us to control the amount of charge in the beams of accelerated electrons and final energy of the electrons. Results are presented from a recent experiment on controlled injection using the scheme of colliding pulses and performed using the Lund multi-terawatt laser. Each laser pulse is split into two parts close to the interaction point. The main pulse is focused on a 2 mm diameter gas jet to drive a nonlinear plasma wave below threshold for self-trapping. The second pulse, containing only a fraction of the total laser energy, is focused to collide with the main pulse in the gas jet under an angle of 150°. Beams of accelerated electrons with low divergence and small energy spread are produced using this set-up. Control over the amount of accelerated charge is achieved by rotating the plane of polarization of the second pulse in relation to the main pulse. Furthermore, the peak energy of the electrons in the beams is controlled by moving the collision point along the optical axis of the main pulse, and thereby changing the acceleration length in the plasma. - Highlights: • Compact colliding pulse injection set-up used to produce low energy spread e-beams. • Beam charge controlled by rotating the polarization of injection pulse. • Peak energy controlled by point of collision to vary the acceleration length.

Fractional variational calculus in terms of Riesz fractional derivatives

International Nuclear Information System (INIS)

Agrawal, O P

2007-01-01

This paper presents extensions of traditional calculus of variations for systems containing Riesz fractional derivatives (RFDs). Specifically, we present generalized Euler-Lagrange equations and the transversality conditions for fractional variational problems (FVPs) defined in terms of RFDs. We consider two problems, a simple FVP and an FVP of Lagrange. Results of the first problem are extended to problems containing multiple fractional derivatives, functions and parameters, and to unspecified boundary conditions. For the second problem, we present Lagrange-type multiplier rules. For both problems, we develop the Euler-Lagrange-type necessary conditions which must be satisfied for the given functional to be extremum. Problems are considered to demonstrate applications of the formulations. Explicitly, we introduce fractional momenta, fractional Hamiltonian, fractional Hamilton equations of motion, fractional field theory and fractional optimal control. The formulations presented and the resulting equations are similar to the formulations for FVPs given in Agrawal (2002 J. Math. Anal. Appl. 272 368, 2006 J. Phys. A: Math. Gen. 39 10375) and to those that appear in the field of classical calculus of variations. These formulations are simple and can be extended to other problems in the field of fractional calculus of variations

Using harmonic oscillators to determine the spot size of Hermite-Gaussian laser beams

Science.gov (United States)

Steely, Sidney L.

1993-01-01

The similarity of the functional forms of quantum mechanical harmonic oscillators and the modes of Hermite-Gaussian laser beams is illustrated. This functional similarity provides a direct correlation to investigate the spot size of large-order mode Hermite-Gaussian laser beams. The classical limits of a corresponding two-dimensional harmonic oscillator provide a definition of the spot size of Hermite-Gaussian laser beams. The classical limits of the harmonic oscillator provide integration limits for the photon probability densities of the laser beam modes to determine the fraction of photons detected therein. Mathematica is used to integrate the probability densities for large-order beam modes and to illustrate the functional similarities. The probabilities of detecting photons within the classical limits of Hermite-Gaussian laser beams asymptotically approach unity in the limit of large-order modes, in agreement with the Correspondence Principle. The classical limits for large-order modes include all of the nodes for Hermite Gaussian laser beams; Sturm's theorem provides a direct proof.

Laser-driven particle and photon beams and some applications

International Nuclear Information System (INIS)

Ledingham, K W D; Galster, W

2010-01-01

Outstanding progress has been made in high-power laser technology in the last 10 years with laser powers reaching petawatt (PW) values. At present, there are 15 PW lasers built or being built around the world and plans are afoot for new, even higher power, lasers reaching values of exawatt (EW) or even zetawatt (ZW) powers. Petawatt lasers generate electric fields of 10 12 V m -1 with a large fraction of the total pulse energy being converted to relativistic electrons with energies reaching in excess of 1 GeV. In turn these electrons result in the generation of beams of protons, heavy ions, neutrons and high-energy photons. These laser-driven particle beams have encouraged many to think of carrying out experiments normally associated with conventional nuclear accelerators and reactors. To this end a number of introductory articles have been written under a trial name 'Laser Nuclear Physics' (Ledingham and Norreys 1999 Contemp. Phys. 40 367, Ledingham et al 2002 Europhys. News. 33 120, Ledingham et al 2003 Science 300 1107, Takabe et al 2001 J. Plasma Fusion Res. 77 1094). However, even greater strides have been made in the last 3 or 4 years in laser technology and it is timely to reassess the potential of laser-driven particle and photon beams. It must be acknowledged right from the outset that to date laser-driven particle beams have yet to compete favourably with conventional nuclear accelerator-generated beams in any way and so this is not a paper comparing laser and conventional accelerators. However, occasionally throughout the paper as a reality check, it will be mentioned what conventional nuclear accelerators can do.

Laser-driven particle and photon beams and some applications

Energy Technology Data Exchange (ETDEWEB)

Ledingham, K W D; Galster, W, E-mail: K.Ledingham@phys.strath.ac.u [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

2010-04-15

Outstanding progress has been made in high-power laser technology in the last 10 years with laser powers reaching petawatt (PW) values. At present, there are 15 PW lasers built or being built around the world and plans are afoot for new, even higher power, lasers reaching values of exawatt (EW) or even zetawatt (ZW) powers. Petawatt lasers generate electric fields of 10{sup 12} V m{sup -1} with a large fraction of the total pulse energy being converted to relativistic electrons with energies reaching in excess of 1 GeV. In turn these electrons result in the generation of beams of protons, heavy ions, neutrons and high-energy photons. These laser-driven particle beams have encouraged many to think of carrying out experiments normally associated with conventional nuclear accelerators and reactors. To this end a number of introductory articles have been written under a trial name 'Laser Nuclear Physics' (Ledingham and Norreys 1999 Contemp. Phys. 40 367, Ledingham et al 2002 Europhys. News. 33 120, Ledingham et al 2003 Science 300 1107, Takabe et al 2001 J. Plasma Fusion Res. 77 1094). However, even greater strides have been made in the last 3 or 4 years in laser technology and it is timely to reassess the potential of laser-driven particle and photon beams. It must be acknowledged right from the outset that to date laser-driven particle beams have yet to compete favourably with conventional nuclear accelerator-generated beams in any way and so this is not a paper comparing laser and conventional accelerators. However, occasionally throughout the paper as a reality check, it will be mentioned what conventional nuclear accelerators can do.

Fractional Schroedinger equation

International Nuclear Information System (INIS)

Laskin, Nick

2002-01-01

Some properties of the fractional Schroedinger equation are studied. We prove the Hermiticity of the fractional Hamilton operator and establish the parity conservation law for fractional quantum mechanics. As physical applications of the fractional Schroedinger equation we find the energy spectra of a hydrogenlike atom (fractional 'Bohr atom') and of a fractional oscillator in the semiclassical approximation. An equation for the fractional probability current density is developed and discussed. We also discuss the relationships between the fractional and standard Schroedinger equations

Laser assisted jet nozzle isotope separation

International Nuclear Information System (INIS)

1981-01-01

A process for separating fluent particles having different masses comprises the steps of: driving a fluent mixture of such particles around a curved passage toward a septum oriented to divide the mixture thereby accelerating such particles to impart a centrifugal force thereto; inducing type selective heating of a selected particle type in said mixture prior to termination of such acceleration; receiving the fraction of the mixture flowing past an outer surface of said septum in a first output conduit; and receiving the fraction of the mixture flowing past an inner surface of said septum in a second output conduit. The description of the process for isotope separation refers also to the use of infrared laser radiation to produce isotopically selective excitation of the U-235 isotope in UF 6 . (author)

Fractional thermoelasticity

CERN Document Server

Povstenko, Yuriy

2015-01-01

This book is devoted to fractional thermoelasticity, i.e. thermoelasticity based on the heat conduction equation with differential operators of fractional order. Readers will discover how time-fractional differential operators describe memory effects and space-fractional differential operators deal with the long-range interaction. Fractional calculus, generalized Fourier law, axisymmetric and central symmetric problems and many relevant equations are featured in the book. The latest developments in the field are included and the reader is brought up to date with current research.  The book contains a large number of figures, to show the characteristic features of temperature and stress distributions and to represent the whole spectrum of order of fractional operators.  This work presents a picture of the state-of-the-art of fractional thermoelasticity and is suitable for specialists in applied mathematics, physics, geophysics, elasticity, thermoelasticity and engineering sciences. Corresponding sections of ...

Controlled light localisation and nonlinear-optical interactions of short laser pulses in holey fibres

International Nuclear Information System (INIS)

Fedotov, Andrei B; Zheltikov, Aleksei M; Golovan', Leonid A; Kashkarov, Pavel K; Tarasevitch, A P; Podshivalov, Alexey A; Alfimov, Mikhail V; Ivanov, Anatoliy A; Beloglazov, V I; Haus, J W; Linde, D von der

2001-01-01

The influence of the structure of holey-fibre cladding on the effective waveguide mode area and the spectral broadening of femtosecond pulses of titanium-sapphire and forsterite lasers is experimentally studied. These experiments demonstrate that the increase in the air-filling fraction of the holey-fibre cladding may substantially enhance the spectral broadening of laser pulses due to the increase in the degree of light localisation in the fibre core. (femtosecond technologies)

Short-pulsed laser for the treatment of tattoos, pigmented lesions, scars and rejuvenation.

Science.gov (United States)

Tanghetti, Emil A; Hoffmann, Kristina Andrea; Hoffmann, Klaus

2017-12-01

This review describes the use of picosecond lasers for the treatment of tattoos, pigmented lesions, scars, and their use in rejuvenation. These devices have delivered enhanced efficacy for the treatment of tattoos and pigmented lesions when compared to the older 40-50 nanosecond devices. The fractional delivery with the picosecond devices have opened up a new method of rejuvenation for photodamaged skin and the treatment of scars. The delivery of these high-energy short pulses have created zones of injury in the skin referred to as areas of laser-induced optical breakdown. These areas of damage appear to produce cytokines and chemokines which result in epidermal and dermal repair and remodeling. The dual use of these devices with the flat and the fractional optics have made these devices useful in many ways that have been unanticipated. ©2017 Frontline Medical Communications.

Ultrasonic study on ternary liquid systems by laser-sound interaction

International Nuclear Information System (INIS)

Behboudnia, M.; Necati Ecevit, F.; Aydin, R.

1994-01-01

To investigate the ultrasound velocity in liquid mixtures an interferometer based on Raman-Nath diffraction of laser light by sound waves is described. Ultrasonic velocity measurements in water in dependence of temperature and in carboxylic acids with triethylamine in benzene of different mole fractions are presented. (author). 14 refs, 4 figs, 1 tab

Fractional quantum mechanics

CERN Document Server

Laskin, Nick

2018-01-01

Fractional quantum mechanics is a recently emerged and rapidly developing field of quantum physics. This is the first monograph on fundamentals and physical applications of fractional quantum mechanics, written by its founder. The fractional Schrödinger equation and the fractional path integral are new fundamental physical concepts introduced and elaborated in the book. The fractional Schrödinger equation is a manifestation of fractional quantum mechanics. The fractional path integral is a new mathematical tool based on integration over Lévy flights. The fractional path integral method enhances the well-known Feynman path integral framework. Related topics covered in the text include time fractional quantum mechanics, fractional statistical mechanics, fractional classical mechanics and the α-stable Lévy random process. The book is well-suited for theorists, pure and applied mathematicians, solid-state physicists, chemists, and others working with the Schrödinger equation, the path integral technique...

Intense pulsed light, near infrared pulsed light, and fractional laser combination therapy for skin rejuvenation in Asian subjects: a prospective multi-center study in China.

Science.gov (United States)

Tao, Li; Wu, Jiaqiang; Qian, Hui; Lu, Zhong; Li, Yuanhong; Wang, Weizhen; Zhao, Xiaozhong; Tu, Ping; Yin, Rui; Xiang, Leihong

2015-09-01

Ablative skin rejuvenation therapies have limitations for Asian people, including post-inflammatory hyperpigmentation and long down time. Non-ablative lasers are safer but have limited efficacy. This study is to investigate the safety and efficacy of a combination therapy consisting of intense pulsed light (IPL), near infrared (NIR) light, and fractional erbium YAG (Er:YAG) laser for skin rejuvenation in Asian people. This study recruited 113 subjects from six sites in China. Subjects were randomly assigned to a full-face group, who received combination therapy, and split-face groups, in which one half of the face received combination therapy and the other half received IPL monotherapy. Each subject received five treatment sessions during a period of 90 days. Subjects were followed up at 1 and 3 months post last treatment. Three months after last treatment, the full-face group (n = 57) had a global improvement rate of 29 % and 29 % for wrinkles, 32 % for skin texture, 33 % for pigment spots, 28 % for pore size, respectively. For patients in the split-face groups (n = 54), monotherapy side had a global improvement rate of 23 % and 20 % for wrinkles, 27 % for skin texture, 25 % for pigment spots, 25 % for pore size, respectively. Both combination therapy and monotherapy resulted in significant improvements at the follow-up visits compared to baseline (P < 0.001). Combination therapy showed significantly greater improvements compared to monotherapy at two follow-up visits (P < 0.05). Combination therapy is a safe and more effective strategy than IPL monotherapy for skin rejuvenation in Asian people.

Thermokinetic Modeling of Phase Transformation in the Laser Powder Deposition Process

Science.gov (United States)

Foroozmehr, Ehsan; Kovacevic, Radovan

2009-08-01

A finite element model coupled with a thermokinetic model is developed to predict the phase transformation of the laser deposition of AISI 4140 on a substrate with the same material. Four different deposition patterns, long-bead, short-bead, spiral-in, and spiral-out, are used to cover a similar area. Using a finite element model, the temperature history of the laser powder deposition (LPD) process is determined. The martensite transformation as well as martensite tempering is considered to calculate the final fraction of martensite, ferrite, cementite, ɛ-carbide, and retained austenite. Comparing the surface hardness topography of different patterns reveals that path planning is a critical parameter in laser surface modification. The predicted results are in a close agreement with the experimental results.

Collisionless energy absorption in the short-pulse intense laser-cluster interaction

International Nuclear Information System (INIS)

Kundu, M.; Bauer, D.

2006-01-01

In a previous paper [Phys. Rev. Lett. 96, 123401 (2006)] we have shown by means of three-dimensional particle-in-cell simulations and a simple rigid-sphere model that nonlinear resonance absorption is the dominant collisionless absorption mechanism in the intense, short-pulse laser cluster interaction. In this paper we present a more detailed account of the matter. In particular we show that the absorption efficiency is almost independent of the laser polarization. In the rigid-sphere model, the absorbed energy increases by many orders of magnitude at a certain threshold laser intensity. The particle-in-cell results display maximum fractional absorption around the same intensity. We calculate the threshold intensity and show that it is underestimated by the common overbarrier ionization estimate

Laser doppler perfusion imaging

International Nuclear Information System (INIS)

Waardell, K.

1992-01-01

Recording of tissue perfusion is important in assessing the influence of peripheral vascular diseases on the microcirculation. This thesis reports on a laser doppler perfusion imager based on dynamic light scattering in tissue. When a low power He-Ne laser beam sequentally scans the tissue, moving blood cells generate doppler components in the back-scattered light. A fraction of this light is detected by a photodetector and converted into an electrical signal. In the processor, a signal proportional to the tissue perfusion at each measurement site is calculated and stored. When the scanning procedure is completed, a color-coded perfusion image is presented on a monitor. To convert important aspects of the perfusion image into more quantitative parameters, data analysis functions are implemented in the software. A theory describing the dependence of the distance between individual measurement points and detector on the system amplification factor is proposed and correction algorithms are presented. The performance of the laser doppler perfusion imager was evaluated using a flow simulator. A linear relationship between processor output signal and flow through the simulator was demonstrated for blood cell concentrations below 0.2%. The median sampling depth of the laser beam was simulated by a Monte Carlo technique and estimated to 235 μm. The perfusion imager has been used in the clinic to study perfusion changes in port wine stains treated with argon laser and to investigate the intensity and extension of the cutaneous axon reflex response after electrical nerve stimulation. The fact that perfusion can be visualized without touching the tissue implies elimination of sterilization problems, thus simplifying clinical investigations of perfusion in association with diagnosis and treatment of peripheral vascular diseases. 22 refs

Next generation laser optics for a hybrid fusion-fission power plant

Energy Technology Data Exchange (ETDEWEB)

Stolz, C J; Latkowski, J T; Schaffers, K I

2009-09-10

The successful completion of the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL), followed by a campaign to achieve ignition, creates the proper conditions to begin exploring what development work remains to construct a power plant based on Inertial Confinement Fusion (ICF) technology. Fundamentally, two distinct NIF laser properties must be overcome. The repetition rate must increase from a shot every four hours to several shots per second. Additionally, the efficiency of converting electricity to laser light must increase by 20x to roughly 10 percent. Solid state diode pumped lasers, commercially available for table top applications, have adequate repetition rates and power conversion efficiencies, however, they operate at a tiny fraction of the required energy for an ICF power plant so would need to be scaled in energy and aperture. This paper describes the optics and coatings that would be needed to support this type of laser architecture.

Resonator design and performance estimation for a space-based laser transmitter

Science.gov (United States)

Agrawal, Lalita; Bhardwaj, Atul; Pal, Suranjan; Kamalakar, J. A.

2006-12-01

Development of a laser transmitter for space applications is a highly challenging task. The laser must be rugged, reliable, lightweight, compact and energy efficient. Most of these features are inherently achieved by diode pumping of solid state lasers. Overall system reliability can further be improved by appropriate optical design of the laser resonator besides selection of suitable electro-optical and opto-mechanical components. This paper presents the design details and the theoretically estimated performance of a crossed-porro prism based, folded Z-shaped laser resonator. A symmetrically pumped Nd: YAG laser rod of 3 mm diameter and 60 mm length is placed in the gain arm with total input peak power of 1800 W from laser diode arrays. Electro-optical Q-switching is achieved through a combination of a polarizer, a fractional waveplate and LiNbO 3 Q-switch crystal (9 x 9 x 25 mm) placed in the feedback arm. Polarization coupled output is obtained by optimizing azimuth angle of quarter wave plate placed in the gain arm. Theoretical estimation of laser output energy and pulse width has been carried out by varying input power levels and resonator length to analyse the performance tolerances. The designed system is capable of meeting the objective of generating laser pulses of 10 ns duration and 30 mJ energy @ 10 Hz.

Fractional-order positive position feedback compensator for active vibration control of a smart composite plate

Science.gov (United States)

Marinangeli, L.; Alijani, F.; HosseinNia, S. Hassan

2018-01-01

In this paper, Active Vibration Control (AVC) of a rectangular carbon fibre composite plate with free edges is presented. The plate is subjected to out-of-plane excitation by a modal vibration exciter and controlled by Macro Fibre Composite (MFC) transducers. Vibration measurements are performed by using a Laser Doppler Vibrometer (LDV) system. A fractional-order Positive Position Feedback (PPF) compensator is proposed, implemented and compared to the standard integer-order PPF. MFC actuator and sensor are positioned on the plate based on maximal modal strain criterion, so as to control the second natural mode of the plate. Both integer and fractional-order PPF allowed for the effective control of the second mode of vibration. However, the newly proposed fractional-order controller is found to be more efficient in achieving the same performance with less actuation voltage. Moreover, it shows promising performance in reducing spillover effect due to uncontrolled modes.

Recent developments in laser-driven polarized sources

International Nuclear Information System (INIS)

Young, L.; Coulter, K.P.; Holt, R.J.; Kinney, E.R.; Kowalczyk, R.S.; Potterveld, D.H.; Zghiche, A.

1990-01-01

Recent progress in the performance of laser-driven sources of polarized hydrogen and deuterium is described. The current status of the prototype source, I = 2.5 x 10 17 s -1 , polarization = 0.29 (including atomic fraction), is comparable to classical Stern-Gerlach sources. A scheme to improve source performance by approximately an order of magnitude, using a combination of optical-pumping spin-exchange and RF transitions, is outlined. 8 refs., 2 figs., 1 tab

Fractional statistics and fractional quantized Hall effect

International Nuclear Information System (INIS)

Tao, R.; Wu, Y.S.

1985-01-01

The authors suggest that the origin of the odd-denominator rule observed in the fractional quantized Hall effect (FQHE) may lie in fractional statistics which govern quasiparticles in FQHE. A theorem concerning statistics of clusters of quasiparticles implies that fractional statistics do not allow coexistence of a large number of quasiparticles at fillings with an even denominator. Thus, no Hall plateau can be formed at these fillings, regardless of the presence of an energy gap. 15 references