108 research outputs found
Benchmark of FEM, Waveguide and FDTD Algorithms for Rigorous Mask Simulation
An extremely fast time-harmonic finite element solver developed for the
transmission analysis of photonic crystals was applied to mask simulation
problems. The applicability was proven by examining a set of typical problems
and by a benchmarking against two established methods (FDTD and a differential
method) and an analytical example. The new finite element approach was up to
100 times faster than the competing approaches for moderate target accuracies,
and it was the only method which allowed to reach high target accuracies.Comment: 12 pages, 8 figures (see original publication for images with a
better resolution
Rigorous Simulation of 3D Masks
We perform 3D lithography simulations by using a finite-element solver. To
proof applicability to real 3D problems we investigate DUV light propagation
through a structure of size 9 microns times 4 microns times 65 nm. On this
relatively large computational domain we perform rigorous computations (No
Hopkins) taking into account a grid of 11 times 21 source points with two
polarization directions each. We obtain well converged results with an accuracy
of the diffraction orders of about one percent. The results compare well to
experimental aerial imaging results. We further investigate the convergence of
3D solutions towards quasi-exact results obtained with different methods.Comment: 8 pages, 5 figures (see original publication for images with a better
resolution
Chitosan in Plant Protection
Chitin and chitosan are naturally-occurring compounds that have potential in agriculture with regard to controlling plant diseases. These molecules were shown to display toxicity and inhibit fungal growth and development. They were reported to be active against viruses, bacteria and other pests. Fragments from chitin and chitosan are known to have eliciting activities leading to a variety of defense responses in host plants in response to microbial infections, including the accumulation of phytoalexins, pathogen-related (PR) proteins and proteinase inhibitors, lignin synthesis, and callose formation. Based on these and other proprieties that help strengthen host plant defenses, interest has been growing in using them in agricultural systems to reduce the negative impact of diseases on yield and quality of crops. This review recapitulates the properties and uses of chitin, chitosan, and their derivatives, and will focus on their applications and mechanisms of action during plant-pathogen interactions
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
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