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LED Array (lead + array)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Improvement of Postfractional Laser Erythema with Light-Emitting Diode Photomodulation

DERMATOLOGIC SURGERY, Issue 5 2009
TINA S. ALSTER MD
BACKGROUND The most common side effects of fractional laser skin treatment are erythema and edema. Low-level light therapy and light-emitting diode (LED) devices have been used to stimulate fibroblast activity and hasten wound healing. OBJECTIVE To determine whether LED treatment immediately after fractional laser skin resurfacing affects the severity and duration of postoperative eythema. MATERIALS AND METHODS Twenty patients received treatment with a 590-nm wavelength LED array to randomly selected facial halves immediately after undergoing full-face fractional laser skin resurfacing with a 1,550-nm erbium-doped fiber laser. Differences in erythema between LED-treated and untreated facial halves were recorded at 24, 48, and 96 hours post-treatment. RESULTS The LED-treated facial halves were less erythematous in all 20 patients 24 hours postoperatively. The six patients who received the highest mean energy densities during fractional laser treatment continued to exhibit decreased erythema in the LED-treated areas at 48 hours. At 96 hours post-treatment, no discernible differences between facial halves were observed in any patient. CONCLUSIONS Photomodulation with a 590-nm-wavelength LED array can decrease the intensity and duration of postfractional laser treatment erythema. [source]

Varying ratios of wavelengths in dual wavelength LED photomodulation alters gene expression profiles in human skin fibroblasts

LASERS IN SURGERY AND MEDICINE, Issue 6 2010
D.H. McDaniel MD
Abstract Background and Objective LED photomodulation has been shown to profoundly influence cellular behavior. A variety of parameters with LED photomodulation can alter cellular response in vitro. The effects of one visible and one infrared wavelength were evaluated to determine the optimal ratio to produce a net increase in dermal collagen by altering the ratio of total energy output of each wavelength. The ratio between the two wavelengths (590 and 870,nm) was shifted in 25% increments. Study Design/Materials and Methods Human skin fibroblasts in culture were exposed to a 590/870,nm LED array with total combined energy density fixed at 4.0,mW/cm.. The ratio of 590/870,nm tested parameters were: 100/0%, 75/25%, 50/50%, 25/75%, and 0/100%. These ratios were delivered using pulsed duty cycle of exposure (250,milliseconds "on" time/100,milliseconds "off" time/100,pulses) for a total energy fluence of 0.1,J/cm.. Gene expression was examined using commercially available extra cellular matrix and adhesion molecule RT PCR Arrays (SA Biosciences, Fredrick, MD) at 24,hours post-exposure. Results Different expression profiles were noticed for each of the ratios studied. Overall, there was an average (in an 80 gene array) of 6% expression difference in up or downregulation between the arrays. The greatest increase in collagen I and decrease in collagenase (MMP-1) was observed with 75/25% ratio of 590/870,nm. The addition of increasing proportions of IR wavelengths causes alteration in gene expression profile. The ratios of the wavelengths caused variation in magnitude of expression. Conclusions Cell metabolism and gene expression can be altered by simultaneous exposure to multiple wavelengths of low energy light. Varying the ratios of specific wavelength intensity in both visible and near infrared light therapy can strongly influence resulting fibroblast gene expression patterns. Lasers Surg. Med. 42:540,545, 2010. © 2010 Wiley,Liss, Inc. [source]

Visible light wireless transmission based on optical access network using white light-emitting diode and electroabsorption transceiver

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2010
Yong-Hwan Son
Abstract We propose the visible light communication (VLC) system based on optical access network using light-emitting diode (LED) and electroabsorption transceiver (EAT). The EAT based on electroabsorption modulator is used as an optical network unit in order to be connected with VLC link based on white LED and photodiode (PD). The proposed architecture is demonstrated experimentally, and its performance is verified through the experimental investigation of quality factor and eye pattern of 5 Mbps baseband data. The variation of performance is shown depending on both the existence of the ambient light and the distance between the LED array and PD. A total of 5 Mbps downlink and uplink transmission is verified through 23.2-km single-mode fiber and wireless channel experimentally. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:790,793, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25045 [source]

Fabrication of Flexible Binary Amplitude Masks for Patterning on Highly Curved Surfaces

ADVANCED FUNCTIONAL MATERIALS, Issue 20 2009
Audrey M. Bowen
Abstract This paper describes soft lithography methods that expand current fabrication capabilities by enabling high-throughput patterning on nonplanar substrates. These techniques exploit optically dense elastomeric mask elements embedded in a transparent poly(dimethylsiloxane) (PDMS) matrix by vacuum-assisted microfluidic patterning, UV,ozone-mediated irreversible sealing, and chemical etching. These protocols provide highly flexible photomasks exhibiting either positive- or negative-image contrasts, which serve as amplitude masks for large-area photolithographic patterning on a variety of curved (and planar) surfaces. When patterning on cylindrical surfaces, the developed masks do not experience significant pattern distortions. For substrates with 3D curvatures/geometries, however, the PDMS mask must undergo relatively large strains in order to make conformal contact. The new methods described in this report provide planar masks that can be patterned to compliantly compensate for both the displacements and distortions of features that result from stretching the mask to span the 3D geometry. To demonstrate this, a distortion-corrected grid pattern mask was fabricated and used in conjunction with a homemade inflation device to pattern an electrode mesh on a glass hemisphere with predictable registration and distortion compensation. The showcased mask fabrication processes are compatible with a broad range of substrates, illustrating the potential for development of complex lithographic patterns for a variety of applications in the realm of curved electronics (i.e., synthetic retinal implants and curved LED arrays) and wide field-of-view optics. [source]

Detection of Pretreated Fingerprint Fluorescence Using an LED-based Excitation System

JOURNAL OF FORENSIC SCIENCES, Issue 4 2008
Masahisa Takatsu Ph.D.
Abstract:, Optimization of a light emitting diode (LED)-based excitation system for the detection of pretreated fingerprint fluorescence is described. Fluorescent ridges can usually be excited by irradiation with forensic light sources such as xenon arc lamps or quartz-halogen lamps with high-power output and suitable filters. However, they are too expensive for many crime laboratories in smaller organizations. We concentrated on LEDs which have advantages over conventional light sources in that they are simpler and of lower cost, but the power output and quality of each individual LED unit is not sufficient for the detection of weak fluorescent ridges. To resolve this subject, blue and green LED arrays composed of ninety LED units were adopted and suitable low pass filters for them were designed. An experimental system, consisting of blue and green LED arrays with the suitable low pass filters for illumination, high pass filters for viewing, a digital camera and a computer, was tested. The fluorescent images of cyanoacrylate ester fumed/rhodamine 6G stained fingerprint on white polyethylene sheet and weak fluorescent ridges of ninhydrin/indium chloride treated fingerprint on white paper were successfully detected and photographed. It was shown that the improvement of LED beam in intensity and quality can compensate the disadvantages, resulting in well-contrasted images. [source]