The pathogenesis of Acanthamoeba infections: current status and future implications

Acanthamoeba are opportunistic protozoan parasites that can cause painful, visionthreatening keratitis. However the pathogenesis and pathophysiology of Acanthamoeba keratitis remain incompletely understood. Most cases of Acanthamoeba keratitis develop as a result of poor hygiene in contact lens care but it is unclear how amoebae transmigrate from the environment into the cornea leading to inflammation, photophobia and blindness. Acanthamoeba keratitis has become increasingly important in the past few decades due to increasing populations of contact lens users. The mechanisms associated with the pathogenesis of Acanthamoeba are highly complex, depending on the virulence properties of the parasite, host susceptibility and the environmental conditions. Complete understanding of Acanthamoeba pathogenesis and its associated risks factors should allow us to design strategies for disease prevention and for the rational development of therapeutic interventions against these devastating infections. Acanthamoeba keratitis has become a significant problem in recent years, especially in contact lens wearers exposed to contaminated water

Analysis of Forward-Backward and Lepton Polarization Asymmetries in B→K1ℓ+ℓ−B\to K_{1}\ell^{+}\ell^{-} Decays in the Two-Higgs-doublet Model

The exclusive semileptonic $B\to K_{1}(1270) \ell^{+}\ell^{-}$ ($\ell=\mu , \tau$) decays are analyzed in variants of two Higgs double models (THDMs). The mass eigenstates $K_{1}(1270)$ and $K_{1}(1400)$ are the mixture of two axial-vector SU(3) $^{1}{P}_{1}$ and $^{3}{P}_{1}$ states with the mixing angle $\theta_{K}$. Making use of the form factors calculated in the Light Cone QCD approach and by taking the mixing angle $\theta_{K}=-34^{\circ}$, the impact of the parameters of the THDMs on different asymmetries in above mentioned semileptonic $B$ meson decays are studied. In this context the forward-backward asymmetry and different lepton polarization asymmetries have been analyzed. We have found comprehensive effects of the parameters of the THDMs on the above mentioned asymmetries. Therefore, the precise measurements of these asymmetries at the LHC and different $B$ factories, for the above mentioned processes, can serve as a good tool to put some indirect constraints on the parametric space of the different versions of THDM.Comment: 25 pages, 10 figures, Accepted for Publication in PTEP. arXiv admin note: text overlap with arXiv:0804.0648 by other author

Far field imaging of a dielectric inclusion

A non-iterative topological sensitivity framework for guaranteed far field detection of a dielectric inclusion is presented. The cases of single and multiple measurements of the electric far field scattering amplitude at a fixed frequency are taken into account. The performance of the algorithm is analyzed theoretically in terms of resolution, stability, and signal-to-noise ratio.Comment: 6 pages, 5th International Workshop on New Computational Methods for Inverse Problems, ENS Cachan, Franc

Detection of Electromagnetic Inclusions using Topological Sensitivity

In this article a topological sensitivity framework for far field detection of a diametrically small electromagnetic inclusion is established. The cases of single and multiple measurements of the electric far field scattering amplitude at a fixed frequency are taken into account. The performance of the algorithm is analyzed theoretically in terms of its resolution and sensitivity for locating an inclusion. The stability of the framework with respect to measurement and medium noises is discussed. Moreover, the quantitative results for signal-to-noise ratio are presented. A few numerical results are presented to illustrate the detection capabilities of the proposed framework with single and multiple measurements.Comment: 31 pages, 5 figure

Isolation of Acanthamoeba isolates belonging to T2, T3, T4 and T7 genotypes from environmental samples in Ankara, Turkey

Acanthamoeba keratitis is a blinding infection that is becoming increasingly important in human health. Early diagnosis is a prerequisite for successful treatment and requires identification of Acanthamoeba at the genotypic level. The genus Acanthamoeba consists of both pathogenic and non-pathogenic species and has been recently classified into 13 different genotypes, T1-T12 and T14. More importantly, 95% of Acanthamoeba isolates that produce keratitis belong to T4 genotypes. In this study, we attempted to determine whether predominance of T4 isolates in Acanthamoeba keratitis is due to greater virulence or greater prevalence. We isolated 18 Acanthamoeba isolates from environmental samples in Ankara, Turkey and determined their pathogenic potential by means osmotolerance, temperature tolerance and in vitro cytotoxicity assays using corneal epithelial cells. Ribosomal DNA sequencing revealed that 10 isolates belong to T2, 5 belong to T3, 2 belong to T4 and one belongs to T7 genotype. As expected, T3 and T4 isolates exhibited the most pathogenic traits and were osmotolerant, temperature tolerant and exhibited severe corneal epithelial cell cytotoxicity indicating their pathogenic potential. Overall these data indicate that high frequency of T4 isolates in keratitis cases may well be due to their greater virulence. This is the first report presenting environmental distribution of Acanthamoeba in Ankara, Turkey

An Enhanced Source Location Privacy based on Data Dissemination in Wireless Sensor Networks (DeLP)

open access articleWireless Sensor Network is a network of large number of nodes with limited power and computational capabilities. It has the potential of event monitoring in unattended locations where there is a chance of unauthorized access. The work that is presented here identifies and addresses the problem of eavesdropping in the exposed environment of the sensor network, which makes it easy for the adversary to trace the packets to find the originator source node, hence compromising the contextual privacy. Our scheme provides an enhanced three-level security system for source location privacy. The base station is at the center of square grid of four quadrants and it is surrounded by a ring of flooding nodes, which act as a first step in confusing the adversary. The fake node is deployed in the opposite quadrant of actual source and start reporting base station. The selection of phantom node using our algorithm in another quadrant provides the third level of confusion. The results show that Dissemination in Wireless Sensor Networks (DeLP) has reduced the energy utilization by 50% percent, increased the safety period by 26%, while providing a six times more packet delivery ratio along with a further 15% decrease in the packet delivery delay as compared to the tree-based scheme. It also provides 334% more safety period than the phantom routing, while it lags behind in other parameters due to the simplicity of phantom scheme. This work illustrates the privacy protection of the source node and the designed procedure may be useful in designing more robust algorithms for location privac