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The four most popular search engines PubMed/MEDLINE, ScienceDirect, Scopus and Google Scholar are investigated to assess which search engine is most effective for literature research in laser medicine. Their search features are described and the results of a performance test are compared according to the criteria (1) recall, (2) precision, and (3) importance. As expected, the search features provided by PubMed/MEDLINE with a comprehensive investigation of medical documents are found to be exceptional compared to the other search engines. However the most effective search engine for an overview of a topic is Scopus, followed by ScienceDirect and Google Scholar. With regard to the criterion " importance" Scopus and Google Scholar are clearly more successful than their competitors. © 2011. Source

Beuthan J.,Charite - Medical University of Berlin | Dressler C.,Laser und Medizin Technology GmbH | Zabarylo U.,Charite - Medical University of Berlin | Minet O.,Charite - Medical University of Berlin
Laser Physics Letters | Year: 2010

The use of lasers in the near infrared spectral range for laser-induced tumor therapy (LITT) demands a new understanding of the thermal responses to repetitive heat stress. The analysis of laser-induced fluorescence during vital monitoring offers an excellent opportunity to solve many of the related issues in this field. The laser-induced fluorescence of the cellular coenzyme NADH was investigated for its time and intensity behavior under heat stress conditions. Heat was applied to vital 3T3 cells (from 22°C to 50°C) according to a typical therapeutical time regime. A sharp increase in temperature resulted in non-linear time behavior when the concentration of this vital coenzyme changed. There are indications that biological systems have a delayed reaction on a cellular level. These results are therefore important for further dosimetric investigations. © 2010 by Astro Ltd. Source

Dressler C.,Laser und Medizin Technology GmbH | Schwandt D.,Berlin Technical University of Applied Sciences | Beuthan J.,Charite - Medical University of Berlin | Mildaziene V.,Vytautas Magnus University | And 2 more authors.
Laser Physics Letters | Year: 2010

Minimally invasive laser-induced thermotherapy (LITT) presents an alternative method to conventional tumor therapeutically interventions, such as surgery, chemotherapy, radiotherapy or nuclear medicine. Optical tissue characteristics of tumor cells and their heat-induced changes are essential issues for controlling LITT progressions. Therefore, it is indispensable to exactly know the absorption coefficient μa, the scattering coefficient μs and the anisotropy factor g as well as their changes under rising temperatures in order to simulate the treatment parameters successfully. Optical parameters of two different cancer model tissues - breast cancer cells species MX1 and colon cancer cells species CX1 - were measured in the spectral range 400-1100 nm as well as in the temperature range 37-60°C. The absorption coefficient of both cell species was low throughout the spectral range analyzed, while μs of both species rose with increasing temperatures. The anisotropy factor g however dropped for both tissues with increasing temperatures. Light scatterings inside tissues proceeded continuously forward for all species tested. It was demonstrated that optical tissue properties undergo significant changes along with the vital status of the cells when the temperature increases. © 2010 by Astro Ltd., published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA. Source

Haag S.F.,Charite - Medical University of Berlin | Tscherch K.,University of Hamburg | Arndt S.,Charite - Medical University of Berlin | Kleemann A.,Klosterfrau Berlin GmbH | And 4 more authors.
European Journal of Pharmaceutics and Biopharmaceutics | Year: 2014

Hyperforin is well-known for its anti-inflammatory, anti-tumor, anti-bacterial, and antioxidant properties. The application of a hyperforin-rich verum cream could strengthen the skin barrier function by reducing radical formation and stabilizing stratum corneum lipids. Here, it was investigated whether topical treatment with a hyperforin-rich cream increases the radical protection of the skin during VIS/NIR irradiation. Skin lipid profile was investigated applying HPTLC on skin lipid extracts. Furthermore, the absorption- and scattering coefficients, which influence radical formation, were determined. 11 volunteers were included in this study. After a single cream application, VIS/NIR-induced radical formation could be completely inhibited by both verum and placebo showing an immediate protection. After an application period of 4 weeks, radical formation could be significantly reduced by 45% following placebo application and 78% after verum application showing a long-term protection. Furthermore, the skin lipids in both verum and placebo groups increased directly after a single cream application but only significantly for ceramide [AP], [NP1], and squalene. After long-term cream application, concentration of cholesterol and the ceramides increased, but no significance was observed. These results indicate that regular application of the hyperforin-rich cream can reduce radical formation and can stabilize skin lipids, which are responsible for the barrier function. © 2013 Elsevier B.V. All rights reserved. Source

Friebel M.,Laser und Medizin Technology GmbH | Helfmann J.,Laser und Medizin Technology GmbH | Meinke M.C.,Charite - Medical University of Berlin
Journal of Biomedical Optics | Year: 2010

Plasma osmolarity influences the volume and shape of red blood cells (RBCs). The volume change is inversely related to the hemoglobin concentration and as a consequence to the complex refractive index within the cell. These morphological changes can be linked to changes in the optical behavior of the cells. The optical parameters, absorption coefficient μ a, scattering coefficient μ s, and effective scattering phase function of red blood cells are investigated in dependence on osmolarity in the spectral range from 250 to 1100 nm. Integrating sphere measurements of light transmit-tance and reflectance in combination with inverse Monte-Carlo simulations are carried out for osmolarities from 225 to 400 mosmol/L. Osmolarity changes have a significant influence on the optical parameters, which can in part be explained by changes in the complex refractive index, cell shape, and cell volume. Spherical forms of RBCs induced by low osmolarity show reduced scattering effects compared to the normal RBC biconcave disk shape. Spinocytes, which are crenated erythrocytes induced by high osmolarity, show the highest scattering effects. Even only a 10% change in osmolarity has a drastic influence on the optical parameters, which appears to be of the same order as for 10% hematocrit and oxygen saturation changes. © 2010 Society of Photo-Optical Instrumentation Engineers. Source

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