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51.
Threes Smijs Zoë Dame Ellen de Haas Jan‐Bonne Aans Stan Pavel Henricus Sterenborg 《Photochemistry and photobiology》2014,90(1):189-200
Novel multifunctional photosensitizers (MFPSs), 5,10,15‐tris(4‐N‐methylpyridinium)‐20‐(4‐phenylthio)‐[21H,23H]‐porphine trichloride (PORTH) and 5,10,15‐tris(4‐N‐methylpyridinium)‐20‐(4‐(butyramido‐methylcysteinyl)‐hydroxyphenyl)‐[21H,23H]‐porphine trichloride (PORTHE), derived from 5,10,15‐Tris(4‐methylpyridinium)‐20‐phenyl‐[21H,23H]‐porphine trichloride (Sylsens B) and designed for treatment of onychomycosis were characterized and their functionality evaluated. MFPSs should function as nail penetration enhancer and as photosensitizer for photodynamic treatment (PDT) of onychomycosis. Spectrophotometry was used to characterize MFPSs with and without 532 nm continuous‐wave 5 mW cm?2 laser light (± argon/mannitol/NaN3). Nail penetration enhancement was screened (pH 5, pH 8) using water uptake in nails and fluorescence microscopy. PDT efficacy was tested (pH 5, ± argon/mannitol/NaN3) in vitro with Trichophyton mentagrophytus microconida (532 nm, 5 mW cm?2). A light‐dependent absorbance decrease and fluorescence increase were found, PORTH being less photostable. Argon and mannitol increased PORTH and PORTHE photostability; NaN3 had no effect. PDT (0.6 J cm?2, 2 μm ) showed 4.6 log kill for PORTH, 4.4 for Sylsens B and 3.2 for PORTHE (4.1 for 10 μm ). Argon increased PORTHE, but decreased PORTH PDT efficacy; NaN3 increased PDT effect of both MFPSs whereas mannitol increased PDT effect of PORTHE only. Similar penetration enhancement effects were observed for PORTH (pH 5 and 8) and PORTHE (pH 8). PORTHE is more photostable, effective under low oxygen conditions and thus realistic candidate for onychomycosis PDT. 相似文献
52.
This study presents a methodology to accurately extract the absorption coefficient from single fiber reflectance spectra measured in turbid media without a priori knowledge of either the reduced scattering coefficient or the phase function. This novel approach accounts for the interrelated effects these properties have on the photon path length, yielding estimates of an absorption coefficient on average within <7.5% of true values over a wide range of biologically relevant optical properties. 相似文献
53.
54.
The two-dimensional striation model consists of a nonlinear system of PDE's which arises in the modeling of the ionospheric plasma. The local-in-time existence of strong solutions is first proved using Banach's fixed point theorem. Then, under physically relevant assumptions, the system is shown to be nonlinearly unstable as soon as it is linearly unstable. Moreover, the instability occurs before the possible blow-up time of the solution. The proof relies on an earlier work of Hwang and Guo (2003). The first step of the proof is to investigate under which conditions the linearized system is unstable and to prove that its spectrum is bounded, by means of a variational formulation. The second one consists in constructing a family of solutions depending on the parameter δ measuring the smallness of the perturbation to the steady-state. Thanks to the boundedness of the linearized spectrum, this family of solutions is shown to be unstable by means of a power series expansion in δ. 相似文献
55.
In this article, we give a brief overview of our recent work on continuum mechanical modelling and simulation of microbial films. This comprises some classical tasks of applied mathematics such as computational fluid dynamics, analysis of partial differential equations, and mathematical biology. 相似文献
56.
Tom A. Middelburg Floor Van Zaane Henriëtte S. De Bruijn Angelique Van Der Ploeg-van den Heuvel Henricus J. C. M. Sterenborg H. A. Martino Neumann Ellen R. M. De Haas Dominic J. Robinson 《Photochemistry and photobiology》2010,86(5):1140-1146
Photodynamic therapy (PDT) for actinic field cancerization is effective but painful. Pain mechanisms remain unclear but fluence rate has been shown to be a critical factor. Lower fluence rates also utilize available oxygen more efficiently. We investigated PDT effect in normal SKH1-HR mice using low and high fluence rate aminolevulinic acid (ALA) PDT and a fractionated illumination scheme. Six groups of six mice with different light treatment parameters were studied. Visual skin damage was assessed up to 7 days post-PDT. Fluorescence and reflectance spectroscopy during illuminations provided us with real-time information about protoporphyrin IX (PpIX) photobleaching. A novel dosing approach was introduced in that we used a photobleaching percentage instead of a preset fluence. Data show similar total and maximum damage scores in high and low fluence rate groups. Photobleaching of PpIX in the low fluence rate groups shows a trend toward more efficient photobleaching. Results indicate that low fluence rate PDT is as effective as and more efficient than high fluence rate PDT in normal mouse skin. Low fluence rate PDT light protocols need to be explored in human studies in search for an effective and well-tolerated treatment for actinic field cancerization. 相似文献
57.
Background
Many systems in nature are characterized by complex behaviour where large cascades of events, or avalanches, unpredictably alternate with periods of little activity. Snow avalanches are an example. Often the size distribution f(s) of a system's avalanches follows a power law, and the branching parameter sigma, the average number of events triggered by a single preceding event, is unity. A power law for f(s), and sigma = 1, are hallmark features of self-organized critical (SOC) systems, and both have been found for neuronal activity in vitro. Therefore, and since SOC systems and neuronal activity both show large variability, long-term stability and memory capabilities, SOC has been proposed to govern neuronal dynamics in vivo. Testing this hypothesis is difficult because neuronal activity is spatially or temporally subsampled, while theories of SOC systems assume full sampling. To close this gap, we investigated how subsampling affects f(s) and sigma by imposing subsampling on three different SOC models. We then compared f(s) and sigma of the subsampled models with those of multielectrode local field potential (LFP) activity recorded in three macaque monkeys performing a short term memory task. 相似文献58.
HJ. Mellin 《Acta Mathematica》1887,9(1):137-166
Ohne Zusammenfassung 相似文献
59.
H J Sterenborg H van Weelden J C van der Leun 《Journal of photochemistry and photobiology. B, Biology》1988,2(2):179-194
Groups of hairless mice were irradiated daily with Philips TL01 UVB sources. This type of lamp has become available recently and was developed for UVB phototherapy of psoriasis. The TL01 emits radiation in a narrow band around 311-312 nm. Tumours developed on all animals. The dose-response relationship had practically the same shape as that found in a similar experiment with Westinghouse FS40 sunlamps; the tumour induction time appeared to be proportional to the daily dose to a power of -0.58. An additional experiment was performed with a TL01 from which the shorter wavelengths were filtered away. This reduced the carcinogenic effectiveness by a factor of 2.3. The potential of the filtered lamp for phototherapy of psoriasis is discussed. 相似文献
60.
Toman Rudolf Garidel Patrick Andrä Jörg Slaba Katarina Hussein Ahmed Koch Michel HJ Brandenburg Klaus 《BMC biochemistry》2004,5(1):1-14