Active Mamyshev regenerator

In this contribution, we numerically and experimentally investigate the extension of the so-called Mamyshev regenerator with the implementation of an additional Raman gain. We evaluate the potential efficiency and advantages of this new active Mamyshev regenerator at 40 Gbps and we highlight a strong reduction of the working power as well as a large improvement of the available output power.     

Phospholipid–Detergent Conjugates as Novel Tools for siRNA Delivery

One of the potential benefits of drug delivery systems in medicine is the creation of nanoparticle‐based vectors that deliver a therapeutic cargo in sufficient quantity to a target site to enable a selective effect, width of the therapeutic window depending on the toxicity of the vector and the cargo. In this work, we intended to improve the siRNA delivery efficiency of a new kind of nucleic acid carrier, which is the result of the conjugation of the membrane phospholipid 1,2‐dioleoyl‐sn‐glycero‐3‐phosphocholine (DOPC) to the membrane‐active species Triton X‐100 (TX100). We hypothesized that by improving the biodegradability the cytotoxicity of the conjugate might by reduced, whereas its original transfection potential would be tentatively preserved. DOPC was conjugated to Triton X‐100 through spacers displaying various resistance to chemical hydrolysis and enzyme degradation. The results obtained through in vitro siRNA delivery experiments showed that the initial phosphoester bond can be replaced with a phospho(alkyl)enecarbonate group with no loss in the transfection activity, whereas the associated cytotoxicity was significantly decreased, as assessed by metabolic activity and membrane integrity measurements. The toxicity of the conjugates incorporating a phospho(alkyl)enesuccinnate moiety proved even lower but was clearly balanced with a reduction of the siRNA delivery efficiency. Hydrolytic stability and intracellular degradation of the conjugates were investigated by NMR spectroscopy and mass spectrometry. A general trend was that the more readily degraded conjugates were those with the lower toxicity. Otherwise, the phospho(alkyl)enecarbonate conjugates revealed some hemolytic activity, whereas the parent phosphoester did not. The reason why these conjugates behave differently with respect to hemolysis might be a consequence of unusual fusogenic properties and probably reflects the difference in the stability of the conjugates in the intracellular environment.     

A column generation heuristic for districting the price of a financial product

This paper studies a districting problem that arises in the context of financial product pricing. The challenge lies in partitioning a set of small geographical regions into a set of larger territories. In each territory, the customers will share a common price. These territories need to be contiguous, contain enough customers and be as homogeneous as possible in terms of customer value. To address this problem, we present a column generation-based heuristic where the subproblem generates contiguous territories taken into account a nonlinear objective function. Computational results indicate that the territories produced by this heuristic are about 35% more homogeneous than those previously used in practice. The developed algorithm has been transferred to a financial firm and is now used to help craft more competitive financial products.     

Bending Moment in Membrane Theory

A model of nonlinear membrane is proposed where the external loading induces a density of bending moments. The mathematical justification of this model is obtained through a 3D–2D dimension reduction via a Γ-convergence analysis taking into account the Cosserat vector field.     

Fourier transform spectroscopy around 3 μm with a broad difference frequency comb

We characterize a new mid-infrared frequency comb generator based on difference frequency generation around 3.1 μm. High power per comb mode (>10^?7 W/mode) is obtained over a broad spectral span (>750 nm, >790 cm^?1). The source is used for direct absorption spectroscopy with a Michelson-based Fourier transform interferometer.