High power 405 nm diode laser fiber-coupled single-mode system with high long-term stability

Fiber-coupled 405 nm diode laser systems are rarely used with fiber output powers higher than 50 mW. A quick degradation of fiber-coupled high power modules with wavelengths in the lower range of the visible spectrum is known for several years. Meanwhile, the typical power of single-mode diode lasers around 400 nm is in the order of 100 to 300 mW, leading to single-mode fiber core power densities in the 1 MW/cm² range. This is three magnitudes of order below the known threshold for optical damage. Our profound investigations on the influence of 405 nm laser light irradiation of single-mode fibers found the growth of periodic surface structures in the form of ripples responsible for the power loss. The ripples are found on the proximal and distal fiber end surfaces, negatively impacting power transmission and beam quality, respectively. Important parameters in the generation of the surface structures are power density, surface roughness and polarization direction. A fiber-coupled high-power 405 nm diode laser system with a high long-term stability will be introduced and described

Effect of the unpolarized spin state in spin-correlation measurement of two protons produced in the 12C(d,2He) reaction

In this note we discuss the effect of the unpolarized state in the spin-correlation measurement of the $^1S_0$ two-proton state produced in 12C(d,2He) reaction at the KVI, Groningen. We show that in the presence of the unpolarized state the maximal violation of the CHSH-Bell inequality is lower than the classical limit if the purity of the state is less than $\sim \verb+70$. In particular, for the KVI experiment the violation of the CHSH-Bell inequality should be corrected by a factor $\sim\verb+10$ from the pure $^1S_0$ state.Comment: 6 pages, to appear in J. Phys.

Fostering European Collaborations: EUFRAT and work done at the accelerator facilities of JRC-IRMM

The European Commission via the General Directorate RTD in its different Framework Programs supported collaborations of member state institutions dealing with nuclear data. The projects EFNUDAT, ERINDA, CHANDA and EUFRAT all have in common Transnational Access Activities (TAA) to partner institutions. Within the past 10 years the collaborations have grown and in CHANDA now 35 partners are involved of which 16 offer TAA to their facilities. Since June 2014 JRC-IRMM, one of the driving forces behind the TAA, launched its own TAA project EUFRAT to foster collaborations with member states institutions. The calls for proposals are open ended with a deadline twice a year. A Project Advisory Committee discusses the proposals and decides on about approval. Financial support is given to approved proposals for two scientists. So far two calls have been evaluated with a request for access totalling more than 5000 h. Examples of proposals at the accelerator facilities at the JRC-IRMM are presented showing the multitude of possibilities using the nuclear facilities at the JRC-IRMM

RNAi Trigger Delivery into Anopheles gambiae Pupae

Citation: Regna, K., Harrison, R. M., Heyse, S. A., Chiles, T. C., Michel, K., & Muskavitch, M. A. T. (2016). RNAi Trigger Delivery into Anopheles gambiae Pupae. Jove-Journal of Visualized Experiments(109), 9. doi:10.3791/53738RNA interference (RNAi), a naturally occurring phenomenon in eukaryotic organisms, is an extremely valuable tool that can be utilized in the laboratory for functional genomic studies. The ability to knockdown individual genes selectively via this reverse genetic technique has allowed many researchers to rapidly uncover the biological roles of numerous genes within many organisms, by evaluation of loss-of-function phenotypes. In the major human malaria vector Anopheles gambiae, the predominant method used to reduce the function of targeted genes involves injection of double-stranded (dsRNA) into the hemocoel of the adult mosquito. While this method has been successful, gene knockdown in adults excludes the functional assessment of genes that are expressed and potentially play roles during pre-adult stages, as well as genes that are expressed in limited numbers of cells in adult mosquitoes. We describe a method for the injection of Serine Protease Inhibitor 2 (SRPN2) dsRNA during the early pupal stage and validate SRPN2 protein knockdown by observing decreased target protein levels and the formation of melanotic pseudo-tumors in SRPN2 knockdown adult mosquitoes. This evident phenotype has been described previously for adult stage knockdown of SRPN2 function, and we have recapitulated this adult phenotype by SRPN2 knockdown initiated during pupal development. When used in conjunction with a dye-labeled dsRNA solution, this technique enables easy visualization by simple light microscopy of injection quality and distribution of dsRNA in the hemocoel

Efficient implementation of a CCA2-secure variant of McEliece using generalized Srivastava codes

International audienceIn this paper we present efficient implementations of McEliece variants using quasi-dyadic codes. We provide secure parameters for a classical McEliece encryption scheme based on quasi-dyadic generalized Srivastava codes, and successively convert our scheme to a CCA2-secure protocol in the random oracle model applying the Fujisaki-Okamoto transform. In contrast with all other CCA2-secure code-based cryptosystems that work in the random oracle model, our conversion does not require a constant weight encoding function. We present results for both 128-bit and 80-bit security level, and for the latter we also feature an implementation for an embedded device

Polarization Correlations of 1S0 Proton Pairs as Tests of Bell and Wigner Inequalities

In an experiment designed to overcome the loophole of observer dependent reality and satisfying the counterfactuality condition, we measured polarization correlations of 1S0 proton pairs produced in 12C(d,2He) and 1H(d,He) reactions in one setting. The results of these measurements are used to test the Bell and Wigner inequalties against the predictions of quantum mechanics.Comment: 8 pages, 4 figure