Distance distribution in configuration model networks

We present analytical results for the distribution of shortest path lengths between random pairs of nodes in configuration model networks. The results, which are based on recursion equations, are shown to be in good agreement with numerical simulations for networks with degenerate, binomial and power-law degree distributions. The mean, mode and variance of the distribution of shortest path lengths are also evaluated. These results provide expressions for central measures and dispersion measures of the distribution of shortest path lengths in terms of moments of the degree distribution, illuminating the connection between the two distributions.Comment: 28 pages, 7 figures. Accepted for publication in Phys. Rev.

Model-free inference of direct network interactions from nonlinear collective dynamics

The topology of interactions in network dynamical systems fundamentally underlies their function. Accelerating technological progress creates massively available data about collective nonlinear dynamics in physical, biological, and technological systems. Detecting direct interaction patterns from those dynamics still constitutes a major open problem. In particular, current nonlinear dynamics approaches mostly require to know a priori a model of the (often high dimensional) system dynamics. Here we develop a model-independent framework for inferring direct interactions solely from recording the nonlinear collective dynamics generated. Introducing an explicit dependency matrix in combination with a block-orthogonal regression algorithm, the approach works reliably across many dynamical regimes, including transient dynamics toward steady states, periodic and non-periodic dynamics, and chaos. Together with its capabilities to reveal network (two point) as well as hypernetwork (e.g., three point) interactions, this framework may thus open up nonlinear dynamics options of inferring direct interaction patterns across systems where no model is known.Comment: 10 pages, 7 figure

Analytical results for the distribution of shortest path lengths in random networks

We present two complementary analytical approaches for calculating the distribution of shortest path lengths in Erdos-R\'enyi networks, based on recursion equations for the shells around a reference node and for the paths originating from it. The results are in agreement with numerical simulations for a broad range of network sizes and connectivities. The average and standard deviation of the distribution are also obtained. In the case that the mean degree scales as $N^{\alpha}$ with the network size, the distribution becomes extremely narrow in the asymptotic limit, namely almost all pairs of nodes are equidistant, at distance $d=\lfloor 1/\alpha \rfloor$ from each other. The distribution of shortest path lengths between nodes of degree $m$ and the rest of the network is calculated. Its average is shown to be a monotonically decreasing function of $m$, providing an interesting relation between a local property and a global property of the network. The methodology presented here can be applied to more general classes of networks.Comment: 12 pages, 4 figures, accepted to EP

Synthetic cells synthesize therapeutic proteins inside tumors

The existing dogma is that protein medicines need to be produced in large factories, and then injected to the patient. We propose that miniature artificial inert factories can be injected to the patient, to produce a protein of interest directly in the diseased tissue. We engineered artificial cell-like particles with an autonomous capacity to synthesize protein drugs after receiving an external signal. The protein is tuned to the patient\u27s needs based on a predetermined DNA code we incorporate inside the particles. This approach increases treatment efficiency and reduces adverse effects to healthy tissues. We developed a new T7-S30 based cell-free protein synthesis system, which contains all the transcription and translation machines and molecules required for protein production (Krinsky et al., PloS one 2016). This system was used to prepare liposomes that act as artificial cells, capable of producing proteins autonomously in response to a physical trigger. Functional enzymes (luciferase and tyrosinase) and fluorescent proteins (GFP) were successfully produced using the new cell-free protein synthesis system and inside the particles both in vitro and in vivo. In addition, we demonstrated the therapeutic capabilities of the protein producing particles by producing Pseudomonas exotoxin A, an extremely potent protein, for treating cancer. Applying the particles on 4T1 cells (a triple-negative breast cancer cell-line) in vitro or injecting them into a 4T1-induced tumor in vivo, resulted in high cytotoxicity due to the effective production of the therapeutic protein inside the vesicles (Krinsky et al. Advanced Healthcare Materials, 2017). Synthetic cells serve as autonomous, trigger-able, artificial particles that produces a variety of proteins. This platform has promise to address a wide range of fundamental questions associated with protein synthesis in nature, as well as applicative protein delivery needs. Please click Additional Files below to see the full abstract

The scientific payload of the Ultraviolet Transient Astronomy Satellite (ULTRASAT)

The Ultraviolet Transient Astronomy Satellite (ULTRASAT) is a space-borne near UV telescope with an unprecedented large field of view (200 sq. deg.). The mission, led by the Weizmann Institute of Science and the Israel Space Agency in collaboration with DESY (Helmholtz association, Germany) and NASA (USA), is fully funded and expected to be launched to a geostationary transfer orbit in Q2/3 of 2025. With a grasp 300 times larger than GALEX, the most sensitive UV satellite to date, ULTRASAT will revolutionize our understanding of the hot transient universe, as well as of flaring galactic sources. We describe the mission payload, the optical design and the choice of materials allowing us to achieve a point spread function of ~10arcsec across the FoV, and the detector assembly. We detail the mitigation techniques implemented to suppress out-of-band flux and reduce stray light, detector properties including measured quantum efficiency of scout (prototype) detectors, and expected performance (limiting magnitude) for various objects.Comment: Presented in the SPIE Astronomical Telescopes + Instrumentation 202