Preeminent role of the Van Hove singularity in the strong-coupling analysis of scanning tunneling spectroscopy for two-dimensional cuprates

In two dimensions the non-interacting density of states displays a Van Hove singularity (VHS) which introduces an intrinsic electron-hole asymmetry, absent in three dimensions. We show that due to this VHS the strong-coupling analysis of tunneling spectra in high-$T_c$ superconductors must be reconsidered. Based on a microscopic model which reproduces the experimental data with great accuracy, we elucidate the peculiar role played by the VHS in shaping the tunneling spectra, and show that more conventional analyses of strong-coupling effects can lead to severe errors.Comment: 5 pages, 4 figure

State space model of a hydraulic power take off unit for wave energy conversion employing bondgraphs

In this work, the modeling of a Power Take- Off (PTO) unit for a point absorber wave energy converter is described. The PTO influences the energy conversion performance by its efficiency and by the damping force exerted, which affects the motion of the body. The state space model presented gives a description of the damping force and of the internal dynamics of the PTO. The aim of this work is to develop a model for the PTO as a part of a complete wave-to-wire model of a wave energy converter as in Figure 1, used for the design control techniques. Figure 1: Wave-to-wire model structure A bondgraph is employed to model the physical system that provides transparent and methodical means of formulating state space equations and of visualizing energy transfer throughout the system. Bondgraphs have already been shown to be a very useful tool for the modeling of PTO for wave energy converters (2). The dynamic of the mathematical model is then analyzed respect to the variation of parameters; in particular, the non-linear system obtained is linearized and its eigenvalues are calculated as function of the accumulator size and pre-charge pressur

A control system for a self-reacting point absorber wave energy converter subject to constraints

The problem of the maximization of the energy produced by a self reacting point absorber subject to motion restriction is addressed. The main objective is to design a control system suitable for real-time implementation. The method presented for the solution of the optimization problem is based on the approximation of the motion of the device and of the force exerted by the power take off unit by means of a linear combination of basis functions. The result is that the optimal control problem is reformulated as a non linear program where the properties of the cost function and of the constraint are affected by the choice of the basis functions. An example is described where the motion and the force are approximated using Fourier series; an optimization algorithm for the solution of the non linear program is also presented. The control system is implemented and simulated using a real sea profile measured by a waverider buoy

State space model of a hydraulic power take off unit for wave energy conversion employing bondgraphs

In this work, the modeling of a Power Take- Off (PTO) unit for a point absorber wave energy converter is described. The PTO influences the energy conversion performance by its efficiency and by the damping force exerted, which affects the motion of the body. The state space model presented gives a description of the damping force and of the internal dynamics of the PTO. The aim of this work is to develop a model for the PTO as a part of a complete wave-to-wire model of a wave energy converter as in Figure 1, used for the design control techniques. Figure 1: Wave-to-wire model structure A bondgraph is employed to model the physical system that provides transparent and methodical means of formulating state space equations and of visualizing energy transfer throughout the system. Bondgraphs have already been shown to be a very useful tool for the modeling of PTO for wave energy converters (2). The dynamic of the mathematical model is then analyzed respect to the variation of parameters; in particular, the non-linear system obtained is linearized and its eigenvalues are calculated as function of the accumulator size and pre-charge pressur

Harmonized tuning of nucleic acid and lectin binding properties with multivalent cyclodextrins for macrophage-selective gene delivery

Polycationic amphiphilic cyclodextrins (paCDs) have been shown to behave as efficient non-viral gene carriers paralleling the efficacy of commercial vectors towards a variety of cell lines. Their molecular framework and modular design allow the installation of saccharidic antennae to promote specific carbohydrate–protein interactions, thus potentially endowing them with selective targeting abilities. Yet, the presence of these additional functionalities onto the polycationic cluster may hamper paCD self-assembly and nucleic acid condensation. In this report we describe the influence of paCD mannosylation extent on paCD-pDNA nanocomplex stability as well as the consequences of varying glycotope density on mannose-specific lectin recognition and gene delivery capabilities. The work aims at exploring the potential of this approach to optimize both properties in order to modulate cell transfection selectivity.Ministerio de Economía y Competitividad SAF2013-44021-RJunta de Andalucía FQM-146

The system to mitigate sediment deposition in the upper surface of the Digital Optical Module in KM3NeT: Part II

The experiments ANTARES and NEMO have shown the accumulation of a thin layer of material in the upper surface of the Optical Modules (OMs). The proposed vibration system to remove this sedimentation from the DOMs surface was tested successfully in a water tank at atmospheric pressure (see [2]). In this note we describe the behaviour of the system in an hyperbaric chamber at a pressure of 360 bar, close to the operating conditions in the sea. We find that the effect of the pressure does not significantly affect the vibration intensity in the glass spher

Recent development of prebiotic research — statement from an expert workshop

A dietary prebiotic is defined as ‘a substrate that is selectively utilized by host microorganisms conferring a health benefit’. Although this definition evolved concomitantly with the knowledge and technological developments that accrued in the last twenty years, what qualifies as prebiotic continues to be a matter of debate. In this statement, we report the outcome of a workshop where academic experts working in the field of prebiotic research met with scientists from industry. The workshop covered three main topics: (i) evolution of the prebiotic concept/definition; (ii) the gut modeling in vitro technology PolyFermS to study prebiotic effects; and (iii) the potential novel microbiome-modulating effects associated with vitamins. The future of prebiotic research is very promising. Indeed, the technological developments observed in recent years provide scientists with powerful tools to investigate the complex ecosystem of gut microbiota. Combining multiple in vitro approaches with in vivo studies is key to understanding the mechanisms of action of prebiotics consumption and their potential beneficial effects on the host

Cyclodextrin-based facial amphiphiles: Assessing the impact of the hydrophilic-lipophilic balance in the self-assembly, DNA complexation and gene delivery capabilities

Exhaustive structure–efficacy relationship studies on nonviral gene delivery systems are often hampered by the ill-defined or polydisperse nature of the formulations. Facial amphiphiles based on rigid cage-type molecular scaffolds offer unique possibilities towards these studies. Taking advantage of regioselective functionalization schemes, we have synthesized a library of cationic cyclodextrin (CD) derivatives combining a range of hydrophilic and lipophilic domains. We have scrutinized how the hydrophilic–lipophilic balance (HLB) around the CD scaffold determines their self-assembly capabilities and the DNA binding and release abilities of the corresponding CD[thin space (1/6-em)]:[thin space (1/6-em)]DNA nanocomplexes (CDplexes). These features have been ultimately correlated with their capabilities to deliver a reporter luciferase-encoding pDNA into COS-7 cells. The ensemble of results demonstrates that fine tuning of the HLB is critical to induce compaction of DNA by the CD-based facial amphiphiles into transfection-productive CDplexes.Ministerio de Economia y Competitividad SAF2013- 44021-RJunta de Andalucía FQM2012- 146

The Inducible CXCR3 Ligands Control Plasmacytoid Dendritic Cell Responsiveness to the Constitutive Chemokine Stromal Cell–derived Factor 1 (SDF-1)/CXCL12

The recruitment of selected dendritic cell (DC) subtypes conditions the class of the immune response. Here we show that the migration of human plasmacytoid DCs (pDCs), the blood natural interferon α–producing cells, is induced upon the collective action of inducible and constitutive chemokines. Despite expression of very high levels of CXCR3, pDCs do not respond efficiently to CXCR3 ligands. However, they migrate in response to the constitutive chemokine stromal cell–derived factor 1 (SDF-1)/CXCL12 and CXCR3 ligands synergize with SDF-1/CXCL12 to induce pDC migration. This synergy reflects a sensitizing effect of CXCR3 ligands, which, independently of a gradient and chemoattraction, decrease by 20–50-fold the threshold of sensitivity to SDF-1/CXCL12. Thus, the ability of the constitutive chemokine SDF-1/CXCL12 to induce pDC recruitment might be controlled by CXCR3 ligands released during inflammation such as in virus infection. SDF-1/CXCL12 and the CXCR3 ligands Mig/CXCL9 and ITAC/CXCL1 display adjacent expression both in secondary lymphoid organs and in inflamed epithelium from virus-induced pathologic lesions. Because pDCs express both the lymph node homing molecule l-selectin and the cutaneous homing molecule cutaneous lymphocyte antigen, the cooperation between inducible CXCR3 ligands and constitutive SDF-1/CXCL12 may regulate recruitment of pDCs either in lymph nodes or at peripheral sites of inflammation

High Resolution Frequency Standard Dissemination via Optical Fibre Metropolitan Network

We present in this paper results on a new dissemination system of ultra-stable reference signal at 100 MHz on a standard fibre network. The 100 MHz signal is simply transferred by amplitude modulation of an optical carrier. Two different approaches for compensating the noise introduced by the link have been implemented. The limits of the two systems are analyzed and several solution suggested in order to improve the frequency stability and to further extend the distribution distance. Nevertheless, our system is a good tool for the best cold atom fountains comparison between laboratories, up to 100 km, with a relative frequency resolution of 10-14 at one second integration time and 10-17 for one day of measurement. The distribution system may be upgraded to fulfill the stringent distribution requirements for the future optical clocks