Self-Stabilizing Supervised Publish-Subscribe Systems

In this paper we present two major results: First, we introduce the first self-stabilizing version of a supervised overlay network by presenting a self-stabilizing supervised skip ring. Secondly, we show how to use the self-stabilizing supervised skip ring to construct an efficient self-stabilizing publish-subscribe system. That is, in addition to stabilizing the overlay network, every subscriber of a topic will eventually know all of the publications that have been issued so far for that topic. The communication work needed to processes a subscribe or unsubscribe operation is just a constant in a legitimate state, and the communication work of checking whether the system is still in a legitimate state is just a constant on expectation for the supervisor as well as any process in the system

Fast Hybrid Network Algorithms for Shortest Paths in Sparse Graphs

We consider the problem of computing shortest paths in hybrid networks, in which nodes can make use of different communication modes. For example, mobile phones may use ad-hoc connections via Bluetooth or Wi-Fi in addition to the cellular network to solve tasks more efficiently. Like in this case, the different communication modes may differ considerably in range, bandwidth, and flexibility. We build upon the model of Augustine et al. [SODA \u2720], which captures these differences by a local and a global mode. Specifically, the local edges model a fixed communication network in which O(1) messages of size O(log n) can be sent over every edge in each synchronous round. The global edges form a clique, but nodes are only allowed to send and receive a total of at most O(log n) messages over global edges, which restricts the nodes to use these edges only very sparsely. We demonstrate the power of hybrid networks by presenting algorithms to compute Single-Source Shortest Paths and the diameter very efficiently in sparse graphs. Specifically, we present exact O(log n) time algorithms for cactus graphs (i.e., graphs in which each edge is contained in at most one cycle), and 3-approximations for graphs that have at most n + O(n^{1/3}) edges and arboricity O(log n). For these graph classes, our algorithms provide exponentially faster solutions than the best known algorithms for general graphs in this model. Beyond shortest paths, we also provide a variety of useful tools and techniques for hybrid networks, which may be of independent interest

Facet-, composition- and wavelength-dependent photocatalysis of Ag2_{2}MoO4_{4}

Faceted $\beta$-Ag$_{2}$MoO$_{4}$ microcrystals are prepared by controlled nucleation and growth in diethylene glycol (DEG) or dimethylsulfoxide (DMSO). Both serve as solvents for the liquid-phase synthesis and surface-active agents for the formation of faceted microcrystals. Due to its reducing properties, truncated $\beta$-Ag$_{2}$MoO$_{4}$@Ag octahedra are obtained in DEG. The synthesis in DMSO allows avoiding the formation of elemental silver and results in $\beta$-Ag$_{2}$MoO$_{4}$ cubes and cuboctahedra. Due to its band gap of 3.2 eV, photocatalytic activation of $\beta$-Ag$_{2}$MoO$_{4}$ is only possible under UV-light. To enable $\beta$-Ag$_{2}$MoO$_{4}$ for absorption of visible light, silver-coated $\beta$-Ag$_{2}$MoO$_{4}$@Ag and Ag$_{2}$(Mo$_{0.95}$Cr$_{0.05}$)O$_{4}$ with partial substitution of [MoO4]$^{2-}$ by [CrO4]$^{2-}$ were prepared, too. The photocatalytic activity of all the faceted microcrystals (truncated octahedra, cubes, cuboctahedra) and compositions ($\beta$-Ag$_{2}$MoO$_{4}$, $\beta$-Ag$_{2}$MoO$_{4}$@Ag, $\beta$-Ag$_{2}$(Mo$_{0.95}$Cr$_{0.05}$)O$_{4}$) is compared with regard to the photocatalytic decomposition of rhodamine B and the influence of the respective faceting, composition and wavelength

Monitoring nanoparticle dissolution via fluorescence-colour shift

[La(OH)]$^{2+}$[ICG]$^{−}$$_{2}$ and [La(OH)]$^{2+}$$_{2}$[PTC]$^{4−}$ inorganic–organic hybrid nanoparticles (IOH-NPs) with indocyanine green (ICG) and perylene-3,4,9,10-tetracarboxylate (PTC) as fluorescent dye anions are used for emission-based monitoring of the dissolution of nanoparticles. Whereas ICG shows a deep red emission in the solid [La(OH)]$^{2+}$[ICG]$^{−}$$_{2}$ IOH-NPs, the emission of PTC in the solid [La(OH)]$^{2+}$$_{2}$[PTC]$^{4−}$ IOH-NPs is completely quenched due to π-stacking. After nanoparticle dissolution, the emission of freely dissolved ICG is weak, whereas freely dissolved PTC shows intense green emission. We report on the synthesis of IOH-NPs and nanoparticle characterization as well as on the fluorescence properties and how to avoid undesirable energy transfer between different fluorescent dyes. The emission shift from red (intact solid nanoparticles) to green (freely dissolved dye anions), indicating nanoparticle dissolution, is shown for aqueous systems and verified $\textit{in vitro}$. Based on this first proof-of-the-concept, the IOH-NP marker system can be interesting to monitor nanoparticle dissolution in cells and tissues of small animals and to evaluate cell processes and/or drug-delivery strategies

A Multi-perspective Analysis of Carrier-Grade NAT Deployment

As ISPs face IPv4 address scarcity they increasingly turn to network address translation (NAT) to accommodate the address needs of their customers. Recently, ISPs have moved beyond employing NATs only directly at individual customers and instead begun deploying Carrier-Grade NATs (CGNs) to apply address translation to many independent and disparate endpoints spanning physical locations, a phenomenon that so far has received little in the way of empirical assessment. In this work we present a broad and systematic study of the deployment and behavior of these middleboxes. We develop a methodology to detect the existence of hosts behind CGNs by extracting non-routable IP addresses from peer lists we obtain by crawling the BitTorrent DHT. We complement this approach with improvements to our Netalyzr troubleshooting service, enabling us to determine a range of indicators of CGN presence as well as detailed insights into key properties of CGNs. Combining the two data sources we illustrate the scope of CGN deployment on today's Internet, and report on characteristics of commonly deployed CGNs and their effect on end users

Optical and electrical characterization of poly-Si/SiOx contacts and their implications on solar cell design

Abstract The scope of this paper lies on the phenomenon of free-carrier absorption (FCA) in heavily phosphorus-doped poly-Si layers, applied at solar cells featuring poly-Si/SiO x passivating contacts at the rear. Firstly, FCA is investigated on test structures featuring poly-Si contacts of different thickness and doping level. Secondly, these passivating contacts are integrated into the rear of solar cells featuring a boron-diffused emitter at the front. The infrared (IR) response of the solar cells is analyzed and FCA losses are quantified. In agreement with theory, it is shown that J sc losses due to FCA increase with poly-Si doping level and thickness. For instance, a total J sc loss of ~0.5 mA/cm² is obtained for a 145 nm thick poly-Si layer with a doping concentration of 1.9x10 20 cm -3

The Hantaan Virus Glycoprotein Precursor Is Cleaved at the Conserved Pentapeptide WAASA

AbstractThe medium segment of the tripartite negative-stranded RNA genome of hantaviruses encodes for the predicted glycoprotein precursor GPC. We have demonstrated here the expression of the glycoprotein precursor of Hantaan virus following transfection of mammalian cells. The cleavage of the precursor into the glycoproteins G1 and G2 followed the rules for signal peptides and seemed to occur directly at the pentapeptide motif “WAASA.” Our data indicate that the signal peptidase complex is responsible for the proteolytic processing of the precursor GPC of Hantaan virus. The comparison of this region of the glycoprotein precursor, including the absolutely conserved WAASA motif, suggests a similar cleavage event for all hantavirus glycoproteins

Reversible control of current across lipid membranes by local heating

Lipid membranes are almost impermeable for charged molecules and ions that can pass the membrane barrier only with the help of specialized transport proteins. Here, we report how temperature manipulation at the nanoscale can be employed to reversibly control the electrical resistance and the amount of current that flows through a bilayer membrane with pA resolution. For this experiment, heating is achieved by irradiating gold nanoparticles that are attached to the bilayer membrane with laser light at their plasmon resonance frequency. We found that controlling the temperature on the nanoscale renders it possible to reproducibly regulate the current across a phospholipid membrane and the membrane of living cells in absence of any ion channels