Antimicrobial Effects of Microwave-Induced Plasma Torch (MiniMIP) Treatment on Candida Albicans Biofilms

The susceptibility of Candida albicans biofilms to a non-thermal plasma treatment has been investigated in terms of growth, survival and cell viability by a series of in vitro experiments. For different time periods , the C. albicans strain SC5314 was treated with a microwave-induced plasma torch (MiniMIP). The MiniMIP treatment had a strong effect (reduction factor (RF) = 2.97 after 50 s treatment) at a distance of 3 cm between the nozzle and the superior regions of the biofilms. In addition, a viability reduction of 77% after a 20 s plasma treatment and a metabolism reduction of 90% after a 40 s plasma treatment time were observed for C. albicans. After such a treatment , the biofilms revealed an altered morphology of their cells by atomic force microscopy (AFM). Additionally , fluorescence microscopy and confocal laser scanning microscopy (CLSM) analyses of plasma-treated biofilms showed that an inactivation of cells mainly appeared on the bottom side of the biofilms. Thus, the plasma inactivation of the overgrown surface reveals a new possibility to combat biofilms

Mode-hop-free tuning over 135 GHz of external cavity diode lasers without anti-reflection coating

We report an external cavity diode laser (ECDL), using a diode whose front facet is not antireflection (AR) coated, that has a mode-hop-free (MHF) tuning range greater than 135 GHz. We achieved this using a short external cavity and by simultaneously tuning the internal and external modes of the laser. We find that the precise location of the pivot point of the grating in our laser is less critical than commonly believed. The general applicability of the method, combined with the compact portable mechanical and electronic design, makes it well suited for both research and industrial applications.Comment: 5 pages, 5 figure

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Compact freeform illumination system design for pattern generation with extended light sources

One of the major problems in freeform illumination design in a geometrical optics approximation is picture generation with extended light sources. In contrast to the freeform design with zero-étendue sources, the extension of the light source leads to the typical blurring effect and a contrast reduction of the required irradiance. This effect can be minimized by increasing the distance between the freeform surface and the light source, which according to étendue conservation, results in an impractically large projection optic. To tackle this problem, we propose a design concept consisting of the combination of a pattern-generating double freeform surface for collimated beam shaping, which is calculated for a zero-étendue light source, and an imaging projection system with a telecentric object space. The design concept works independently of the shape of the emission area of the light source and does not require a representation of the extended light source by several individual wavefronts. By interpreting the pattern blurring effect as a composition of a shift contribution and a distortion contribution, we show that both can be minimized simultaneously by an appropriate placement of the object plane of the imaging optics and by making the distance between both freeform surfaces as small as possible. This allows the calculation of compact, energy-efficient freeform illumination systems for picture generation with real extended light sources. We demonstrate the significant blurring reduction by designing a simple illumination system consisting of a collimation optic, a (zero-étendue) double freeform lens for collimated beam shaping, and a projection lens for the generation of the target distribution “Elaine” with an extended Lambertian emitter of 3  mm×3  mm extension and ±42  deg maximum opening angle. For a working distance to the projection system of 500 mm and a target area of 300  mm×300  mm, a relative blurring extension of 2% is estimated, compared to 23% for a single freeform projector with the same energy throughput and similar lateral extension. The influence of the doublefreeform thickness on the blurring reduction is demonstrated, and a summary of the design procedure for the developed design concept is given

Ray mapping approach in double freeform surface design for collimated beam shaping

Laser beam shaping enables the simultaneous redistribution of the irradiance and phase of a laser beam. The desired shape of the laser beam is thereby determined by the respective application. One possible way to achieve the desired irradiance and phase at the same time is from double freeform surfaces. We investigate the numerical design of double freeform surfaces for collimated beam shaping with arbitrary irradiances by using ray-mapping techniques, where at first a proper ray mapping between the source and target irradiance is calculated, and in a subsequent step the freeform surfaces are constructed. The difficulty thereby is to find an integrable ray mapping which leads to two continuous surfaces. Combining the law of refraction and an integrability condition, we derive a condition for a ray mapping and show that it can be fulfilled in a small-angle approximation by a mapping derived with optimal mass transport. As a consequence the design process decouples into the separate calculation of the ray mapping as well as both freeform surfaces. A quantitative estimate for the approximate integrability of the optimal mass transport mapping is derived. The decoupling of the design process offers an efficient way of constructing both freeform surfaces by solving linear advection equations. The efficiency of the design algorithm is demonstrated by applying it to a challenging design example, furthermore the limitations of the numerical approach are investigated