Gravitational Lensing and f(R) theories in the Palatini approach

We investigate gravitational lensing in the Palatini approach to the f(R) extended theories of gravity. Starting from an exact solution of the f(R) field equations, which corresponds to the Schwarzschild-de Sitter metric and, on the basis of recent studies on this metric, we focus on some lensing observables, in order to evaluate the effects of the non linearity of the gravity Lagrangian. We give estimates for some astrophysical events, and show that these effects are tiny for galactic lenses, but become interesting for extragalactic ones.Comment: 7 Pages, RevTex, 1 eps figure; references added; revised to match the version accepted for publication in General Relativity and Gravitatio

Distinct germline genetic susceptibility profiles identified for common non-Hodgkin lymphoma subtypes

Lymphoma risk is elevated for relatives with common non-Hodgkin lymphoma (NHL) subtypes, suggesting shared genetic susceptibility across subtypes. To evaluate the extent of mutual heritability among NHL subtypes and discover novel loci shared among subtypes, we analyzed data from eight genome-wide association studies within the InterLymph Consortium, including 10,629 cases and 9505 controls. We utilized Association analysis based on SubSETs (ASSET) to discover loci for subsets of NHL subtypes and evaluated shared heritability across the genome using Genome-wide Complex Trait Analysis (GCTA) and polygenic risk scores. We discovered 17 genome-wide significant loci (P < 5 × 10−8) for subsets of NHL subtypes, including a novel locus at 10q23.33 (HHEX) (P = 3.27 × 10−9). Most subset associations were driven primarily by only one subtype. Genome-wide genetic correlations between pairs of subtypes varied broadly from 0.20 to 0.86, suggesting substantial heterogeneity in the extent of shared heritability among subtypes. Polygenic risk score analyses of established loci for different lymphoid malignancies identified strong associations with some NHL subtypes (P < 5 × 10−8), but weak or null associations with others. Although our analyses suggest partially shared heritability and biological pathways, they reveal substantial heterogeneity among NHL subtypes with each having its own distinct germline genetic architecture

Analysis of dynamic crack propagation in elastomers by simultaneous tensile- and pure-shear-mode testing

The present work proposes a new fracture mechanical testing concept for determination of dynamic crack propagation of rubber materials. This concept implements a method of simultaneous tensile- and pure-shear-mode testing. The present approach is based on an upgrade of the Tear Analyzer (Co. Coesfeld GmbH & Co. KG), on the fracture mechanics theory of dynamically loaded test specimens and on the definition of pure-shear states according to the test specimen's geometry ratio. The main focus of this work can be divided into three parts. Firstly, it introduces the development of a method for analysis of dynamic crack propagation in filled rubber by simultaneous tensile- and pure shear mode testing. The servo-hydraulic machine with controlled temperature testing chamber is equipped with simultaneously operating two-mode test equipment that represents a new fracture testing method. This two-mode test allows the measurement of crack propagation on different rubber specimens simultaneously and under identical load. The data analysis allows a comparison between the two parallel running testing modes. Secondly, this work deals with the development of a method for the defined creation of a notch in a rubber specimen. This method serves as a basis for the reproducible and reliable determination of fracture mechanical parameters for elastomers. After insertion of notches in a defined way, fracture tests under different loading conditions were performed. A significant influence on the notch geometry was observed in the test results. The results illustrated the importance of a defined and reproducible notching of elastomeric specimens. Next, the analysis of crack propagation under dynamic loading conditions is practiced with this method. It is shown how the tearing energy and the crack growth rate depend on the test specimen's geometry ratio and crack length. It is also demonstrated that the values for tearing energies and crack growth rates for short crack lengths in SENT, as well as in pure-shear test specimens, are identical. Another important aspect of the results is related to the different values of tearing energies and crack growth rates for cracks with short and large lengths in pureshear test specimens. The results show the dependence of fracture behavior on the manufacture of the test specimens. The new fracture mechanical testing concept offers a comparison between fracture behaviors of rubber materials independent of the test specimen's geometry. © Springer-Verlag Berlin Heidelberg 2013.

Compact and efficient single frequency Nd:YVO4 laser with variable longitudinal mode discrimination

We show for the first time that the longitudinal-mode discrimination in a birefringently filtered laser can be tuned through the variation of the waveplating action of the gain crystal. In this way, the laser can be optimized for either high intermodal discrimination or for frequency tuning with reduced output power rolloff. Up to 760 mW of single-frequency 1064-nm output is obtained from a compact diode-pumped source that can be frequency chirped over 6.5 GHz

Preprint: Actions of camptothecin derivatives on larvae and adults of the arboviral vector Aedes aegypti

Mosquito-borne viruses including dengue, Zika and Chikungunya viruses as well as parasites such as malaria and Onchocerca volvulus endanger health and economic security around the globe and emerging mosquito-borne pathogens have pandemic potential. However, the rapid spread of insecticide resistance threatens our ability to control mosquito vectors. Larvae of Aedes aegypti (New Orleans strain) were screened with the Medicines for Malaria Venture Pandemic Response Box, an open-source compound library, using INVAPP, an invertebrate automated phenotyping platform suited to high-throughput chemical screening of larval motility. Of the 400 compounds screened, we identified rubitecan (a synthetic derivative of camptothecin) as a hit compound that significantly reduced Ae. aegypti larval motility compared to DMSO controls. Both rubitecan and camptothecin displayed concentration dependent reduction in larval motility with estimated EC50s of 25.5 ± 5.0 μM and 22.3 ± 5.4 μM respectively. We extended our investigation to adult mosquitoes and found that camptothecin increased lethality when delivered in a blood meal to Ae. aegypti adults at 100 μM and 10 μM and completely blocked egg laying when fed at 100 μM. Camptothecin and its derivatives, inhibitors of topoisomerase I, have known activity against several agricultural pests and are also approved for the treatment of several cancers. Crucially, they can inhibit Zika virus replication in human cells, so there is potential for dual targeting of both the vector and an important arbovirus that it carries. Both humans and mosquitoes express the highly conserved topoisomerase I target, however, the design of derivatives with differing pharmacokinetic properties may offer a promising route towards the development of insect-specificity of this chemistry