73 research outputs found
Treatment of chronic dry eye: focus on cyclosporine
To review the current treatment of chronic dry eye syndrome, focusing on cyclosporine A (CsA), a systematic literature search was performed using PubMed databases in two steps. The first step was oriented to articles published for dry eye. The second step was focused on the use of CsA in dry eye. A manual literature search was also undertaken based on citations in the published articles. The knowledge on the pathogenesis of dry eye syndrome has changed dramatically during the last few years. Inflammation and the interruption of the inflammatory cascade seem to be the main focus of the ophthalmologic community in the treatment of dry eye, giving the anti-inflammatory therapy a new critical role. The infiltration of T-cells in the conjuctiva tissue and the presence of cytokines and proteasis in the tear fluid were the main reason introducing the use of immunomodulator agents such as corticosteroids, cyclosporine, and doxycicline in order to treat dry eye syndrome. CsA emulsion is approved by the FDA for the treatment of dry eye, while clinical trials of this agent have demonstrated efficacy and safety of CsA. CsA seems to be a promising treatment against dry eye disease. New agents focused on the inflammatory pathogenesis of this syndrome in combination with CsA may be the future in the quest of treating dry eye. More studies are needed to determine the efficacy, safety, timing, and relative cost/effect of CsA
On the complexity of color-avoiding site and bond percolation
The mathematical analysis of robustness and error-tolerance of complex
networks has been in the center of research interest. On the other hand, little
work has been done when the attack-tolerance of the vertices or edges are not
independent but certain classes of vertices or edges share a mutual
vulnerability. In this study, we consider a graph and we assign colors to the
vertices or edges, where the color-classes correspond to the shared
vulnerabilities. An important problem is to find robustly connected vertex
sets: nodes that remain connected to each other by paths providing any type of
error (i.e. erasing any vertices or edges of the given color). This is also
known as color-avoiding percolation. In this paper, we study various possible
modeling approaches of shared vulnerabilities, we analyze the computational
complexity of finding the robustly (color-avoiding) connected components. We
find that the presented approaches differ significantly regarding their
complexity.Comment: 14 page
A Bird's Eye View on the I2P Anonymous File-sharing Environment
International audienceAnonymous communications have been gaining more and more interest from Internet users as privacy and anonymity problems have emerged. Among anonymous enabled services, anonymous file-sharing is one of the most active one and is increasingly growing. Large scale monitoring on these systems allows us to grasp how they behave, which type of data is shared among users, the overall behaviour in the system. But does large scale monitoring jeopardize the system anonymity? In this work we present the first large scale monitoring architecture and experiments on the I2P network, a low-latency message-oriented anonymous network. We characterize the file-sharing environment within I2P, and evaluate if this monitoring affects the anonymity provided by the network. We show that most activities within the network are file-sharing oriented, along with anonymous web-hosting. We assess the wide geographical location of nodes and network popularity. We also demonstrate that group-based profiling is feasible on this particular network
Node-weighted measures for complex networks with spatially embedded, sampled, or differently sized nodes
When network and graph theory are used in the study of complex systems, a
typically finite set of nodes of the network under consideration is frequently
either explicitly or implicitly considered representative of a much larger
finite or infinite region or set of objects of interest. The selection
procedure, e.g., formation of a subset or some kind of discretization or
aggregation, typically results in individual nodes of the studied network
representing quite differently sized parts of the domain of interest. This
heterogeneity may induce substantial bias and artifacts in derived network
statistics. To avoid this bias, we propose an axiomatic scheme based on the
idea of node splitting invariance to derive consistently weighted variants of
various commonly used statistical network measures. The practical relevance and
applicability of our approach is demonstrated for a number of example networks
from different fields of research, and is shown to be of fundamental importance
in particular in the study of spatially embedded functional networks derived
from time series as studied in, e.g., neuroscience and climatology.Comment: 21 pages, 13 figure
Spectra of complex networks
We propose a general approach to the description of spectra of complex
networks. For the spectra of networks with uncorrelated vertices (and a local
tree-like structure), exact equations are derived. These equations are
generalized to the case of networks with correlations between neighboring
vertices. The tail of the density of eigenvalues at large
is related to the behavior of the vertex degree distribution
at large . In particular, as , . We propose a simple approximation, which enables us to
calculate spectra of various graphs analytically. We analyse spectra of various
complex networks and discuss the role of vertices of low degree. We show that
spectra of locally tree-like random graphs may serve as a starting point in the
analysis of spectral properties of real-world networks, e.g., of the Internet.Comment: 10 pages, 4 figure
Symmetry in complex networks
We consider the size and structure of the automorphism groups of a variety of empirical ‘real-world’ networks and find that, in contrast to classical random graph models, many real-world networks are richly symmetric. We construct a practical network automorphism group decomposition, relate automorphism group structure to network topology and discuss generic forms of symmetry and their origin in real-world networks. We also comment on how symmetry can affect network redundancy and robustness
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Intrastromal corneal ring segments for the treatment of irregular astigmatism
Intrastromal corneal ring (ICR; INTACS; Addition Technology, Inc., IL, USA) segments were first designed to provide a refractive adjustment by flattening the central corneal curvature while maintaining a prolate aspheric shape in the central optical zone. In contrast to excimer laser refractive techniques, ICR preserves corneal tissue and does not involve the central optical zone. Owing to these tissue-conserving properties, ICR has been proposed as an interesting surgical alternative in patients with corneal ectatic disorders. The treatment options for patients with corneal ectatic diseases and abnormal astigmatism depend on the severity of the disease. In patients with spectacle correction, ICR does not improve visual acuity and rigid contact lenses are not well tolerated; ICR seems to be an interesting, minimally invasive prekeratoplastic surgical technique. There are several publications in the literature supporting the safety and efficacy of this technique in patients with corneal ectatic diseases and abnormal astigmatism. ICR is considered to be a safe, reversible and minimally invasive procedure
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