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Light Reflection (light + reflection)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

A Combination of Selective Light Reflection and Fluorescence Modulation in a Cholesteric Polymer Matrix

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 3 2005
Dasha Medvedeva
Abstract Summary: The phase behavior and optical properties of a cholesteric ternary copolymer, containing nematogenic phenylbenzoate, cholesteric, and photochromic diarylethene side groups, and its mixture with 2 wt.-% fluorescent dopant were studied. The investigation of the kinetics of a photochemical opening-cycle process of the photochromic groups in the cholesteric mixture proved the energy transfer from the fluorescent dopant to the photochromic diarylethene groups. It was shown that the fluorescence intensity of the fluorescent dopant could be controlled by the portion of the "closed" form of the diarylethene groups. During the photocyclization of the photochromic groups a "degeneration" of the selective light reflection of the cholesteric matrix is observed. Fluorescence-resonance energy transfer makes possible the process of photosensitization of the back ring-opening photoreaction of the photochromic diarylethene groups in the cholesteric polymer matrix. [source]

Prevention of Nosocomial Infection During Dermoscopy?

DERMATOLOGIC SURGERY, Issue 4 2006
SUSAN C. KELLY DO
BACKGROUND Dermatoscopes are applied directly to cutaneous or mucocutaneous surfaces with immersion fluid (IF) such as oil or alcohol to reduce light reflection. Recently, Staphylococcus aureus has been isolated from dermatosopes that used mineral oil as the IF. Thus, dermatoscopes might be a potential source of nosocomial infection. OBJECTIVE In this study we propose the use of an alcohol-based antibacterial gel to reduce nosocomial infection transmission while optimizing optical resolution during dermatoscopic examination. MATERIALS AND METHODS Aerobic bacterial cultures were performed on three dermatoscopes used in an outpatient setting after routine examination of 31 patients with an alcohol-based antibacterial gel as IF. RESULTS There was no bacterial growth after using the antibacterial gel with the dermatoscopes. The optical resolution for the antibacterial gel appeared equal to the ,dermatoscopy oil' and superior to alcohol wipes. CONCLUSIONS Alcohol-based antibacterial gel appears to inhibit bacterial colonization while offering excellent optical resolution during dermoscopic examination. The use of alcohol-based IF appears to obviate the risk of nosocomial infections. [source]

Clinical significance of dermoscopy in alopecia areata: analysis of 300 cases

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 7 2008
Shigeki Inui MD
Objective To determine dermoscopic findings of alopecia areata (AA) from a large-scale study that can be used as clinical indicators of disease. Methods Dermoscopic examination of areas of hair loss on the scalp of 300 Asian patients with AA was performed using a DermLite® II pro, which can block light reflection from the skin surface without immersion gels. Using the Spearman rank-order correlation coefficient by rank test, correlations between the incidence of each dermoscopic finding and the severity of disease and disease activity were examined. The sensitivity and specificity of the findings as diagnostic clues for AA were evaluated. Results Characteristic dermoscopic findings of AA included black dots, tapering hairs, broken hairs, yellow dots, and clustered short vellus hairs (shorter than 10 mm) in the areas of hair loss. Black dots, yellow dots, and short vellus hairs correlated with the severity of disease, and black dots, tapering hairs, broken hairs, and short vellus hairs correlated with disease activity. For diagnosis, yellow dots and short vellus hairs were the most sensitive markers, and black dots, tapering hairs, and broken hairs were the most specific markers. Conclusion Dermoscopic characteristics, such as black dots, tapering hairs, broken hairs, yellow dots, and clustered short vellus hairs, are useful clinical indicators for AA. [source]

A Combination of Selective Light Reflection and Fluorescence Modulation in a Cholesteric Polymer Matrix

The distribution of circularly polarized light reflection in the Scarabaeoidea (Coleoptera)

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2010
J. DAVID PYE fls
The light reflected from many scarab beetles is strongly circularly polarized, a phenomenon that may be unique in nature. Approximately 1500 genera and more than 19 000 species/subspecies of scarab beetles (Scarabaeoidea) in the collection of the Natural History Museum, London, were surveyed with circularly polarizing filters to assess how widespread this effect is and how it relates to colour patterns in the individuals concerned. Over 1100 measurements were made of the strength of the circular polarization, in some cases registering 97%. Circular polarization had been previously described from five subfamilies of Scarabaeidae and, in the present study, was found in three further subfamilies: Phaenomeridinae, Dynastinae and Euchirinae, as well as in the subfamily Ceratocanthinae of the family Hybosoridae, comprising the first records outside the Scarabaeidae. The results may have implications for the taxonomy of the group, for visual discrimination, and for the behaviour of the species themselves. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 585,596. [source]

Optical Coherence Tomography: A Noninvasive Method to Assess Wound Reepithelialization

ACADEMIC EMERGENCY MEDICINE, Issue 5 2007
Adam J. Singer MD
BackgroundAccurate assessment of wound healing may require invasive tissue biopsies, limiting its clinical usefulness in humans. Optical coherence tomography (OCT) is a novel, high-resolution method using light reflection to obtain noninvasive cross sectional imaging of biological tissues. ObjectivesTo evaluate the utility of OCT for assessing wound reepithelialization in a porcine model. MethodsThe authors conducted an animal study with two domestic pigs. Excisional cutaneous wounds were created over the ventral surface of the animals using an electric dermatome set at a depth of 600 ,m. The wounds were excised two or three days later and precisely marked to guide initial OCT and subsequent tissue slicing and microscopy. Comparing hematoxylin and eosin,stained histologic sections and the corresponding OCT images from each tissue sample permitted identification of the correlative micromorphology. Scatter and Bland,Altman plots were used to present the data. The primary measure of agreement was the standard deviation of the pairwise differences in percent reepithelialization between OCT and histology together with a 95% confidence interval. ResultsIn normal skin, the epidermis was characterized by a thin, bright layer indicating a high degree of light scattering on OCT. The dermis below was characterized by a thicker, darker area indicating less scattering of light. All fresh excisional wounds lacked an outer bright layer of epidermis immediately after injury. At days 2 and 3, the wounds were partially reepithelialized. A new bright layer with intense light scattering was present on OCT corresponding to the neoepidermis on hematoxylin and eosin,stained sections. The correlation between percent reepithelialization measured with OCT and histology was 0.66 (p < 0.001), and the standard deviation of the differences was 11.0% (95% confidence interval = 8.4% to 16.1%). ConclusionsOCT accurately detects the presence or absence of the epidermal layer of skin, allowing noninvasive tracking of wound reepithelialization. [source]