Context-Awareness Enhances 5G Multi-Access Edge Computing Reliability

The fifth generation (5G) mobile telecommunication network is expected to support Multi- Access Edge Computing (MEC), which intends to distribute computation tasks and services from the central cloud to the edge clouds. Towards ultra-responsive, ultra-reliable and ultra-low-latency MEC services, the current mobile network security architecture should enable a more decentralized approach for authentication and authorization processes. This paper proposes a novel decentralized authentication architecture that supports flexible and low-cost local authentication with the awareness of context information of network elements such as user equipment and virtual network functions. Based on a Markov model for backhaul link quality, as well as a random walk mobility model with mixed mobility classes and traffic scenarios, numerical simulations have demonstrated that the proposed approach is able to achieve a flexible balance between the network operating cost and the MEC reliability.Comment: Accepted by IEEE Access on Feb. 02, 201

Understanding charge transport in organic field effect transistors

The organic electronics research field has advanced tremendously in the last decades, having already led to field-effect mobilities able to compete with their inorganic counterparts. However, many fundamental aspects of this field remain still unclear and need to be clarified before its final blossoming, which would probably come with the complete understanding of the charge transport mechanism in organic materials. It is well-known that the performance of organic semiconductors is governed not only by their molecular structures but also by their intermolecular assembly in the solid state. Therefore, analyzing organic materials from both a molecular and supramolecular point of view is highly desirable. For this end, Raman spectroscopy is a rapid, non invasive technique able to gather information on molecular and supramolecular levels, thus being greatly useful in the organic electronics research field. Analyzing buried interfaces, such as the semiconductor-dielectric interface in organic field effect transistors (OFETs) is fundamental, since the largest contribution to charge transport occurs within the first few nanometers of the semiconductor near the dielectric interface. Surface Enhanced Raman Spectroscopy (SERS) appears as an easy and straightforward technique to carry out this task and to provide useful information on molecular orientation at the device active layer. In this communication, some examples will be presented in which several spectroscopic techniques, conventional Raman and SERS, supported by DFT quantum chemical calculations have been used to shed light on the mechanism of charge transport in OFETs.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Isothermal Titration Calorimetry and Transmission Electron Microscopy of Main-Chain Viologen Polymer Containing Bromide as Counerions

Polyelectrolytes are an important class of macromolecules that contain dissociable ionic groups. When introduced into polar solvent, usually the universal solvent water, dissociation takes place so that electrically charged macromolecule is suspended in solution. The electrostatic interaction is operative between ionized groups inside the macromolecule, between the macromolecules, between the counterions, and between the macromolecule and counterion. Since this interaction is characterized by its long-range nature, the solution exhibits various interesting properties including the polyelectrolyte behavior very different from solutions of neutral polymers

Enhancing malaria diagnosis through microfluidic cell enrichment and magnetic resonance relaxometry detection

Despite significant advancements over the years, there remains an urgent need for low cost diagnostic approaches that allow for rapid, reliable and sensitive detection of malaria parasites in clinical samples. Our previous work has shown that magnetic resonance relaxometry (MRR) is a potentially highly sensitive tool for malaria diagnosis. A key challenge for making MRR based malaria diagnostics suitable for clinical testing is the fact that MRR baseline fluctuation exists between individuals, making it difficult to detect low level parasitemia. To overcome this problem, it is important to establish the MRR baseline of each individual while having the ability to reliably determine any changes that are caused by the infection of malaria parasite. Here we show that an approach that combines the use of microfluidic cell enrichment with a saponin lysis before MRR detection can overcome these challenges and provide the basis for a highly sensitive and reliable diagnostic approach of malaria parasites. Importantly, as little as 0.0005% of ring stage parasites can be detected reliably, making this ideally suited for the detection of malaria parasites in peripheral blood obtained from patients. The approaches used here are envisaged to provide a new malaria diagnosis solution in the near future.Singapore-MIT Alliance for Research and Technology Cente

Rheotaxis facilitates upstream navigation of mammalian sperm cells

A major puzzle in biology is how mammalian sperm determine and maintain the correct swimming direction during the various phases of the sexual reproduction process. Whilst chemotaxis is assumed to dominate in the immediate vicinity of the ovum, it is unclear which biochemical or physical cues guide spermatozoa on their long journey towards the egg cell. Currently debated mechanisms range from peristaltic pumping to temperature sensing (thermotaxis) and direct response to fluid flow variations (rheotaxis), but little is known quantitatively about their relative importance. Here, we report the first quantitative experimental study of mammalian sperm rheotaxis. Using microfluidic devices, we investigate systematically the swimming behavior of human and bull sperm over the whole range of physiologically relevant shear rates and viscosities. Our measurements show that the interplay of fluid shear, steric surface-interactions and chirality of the flagellar beat leads to a stable upstream spiraling motion of sperm cells, thus providing a generic and robust rectification mechanism to support mammalian fertilisation. To rationalise these findings, we identify a minimal mathematical model that is capable of describing quantitatively the experimental observations. The combined experimental and theoretical evidence supports the hypothesis that the shape and beat patterns of mammalian sperm cells have evolved to optimally exploit rheotaxis for long-distance navigation.Comment: 18 pages, 4 figures, supplementary information available at eLifesciences.or

Hillview:A trillion-cell spreadsheet for big data

Hillview is a distributed spreadsheet for browsing very large datasets that cannot be handled by a single machine. As a spreadsheet, Hillview provides a high degree of interactivity that permits data analysts to explore information quickly along many dimensions while switching visualizations on a whim. To provide the required responsiveness, Hillview introduces visualization sketches, or vizketches, as a simple idea to produce compact data visualizations. Vizketches combine algorithmic techniques for data summarization with computer graphics principles for efficient rendering. While simple, vizketches are effective at scaling the spreadsheet by parallelizing computation, reducing communication, providing progressive visualizations, and offering precise accuracy guarantees. Using Hillview running on eight servers, we can navigate and visualize datasets of tens of billions of rows and trillions of cells, much beyond the published capabilities of competing systems

Chromatin-Remodeling Components of the BAF Complex Facilitate Reprogramming

SummaryReprogramming of somatic cells achieved by combination of the four transcription factors Oct4, Sox2, Klf4, and c-Myc has very low efficiency. To increase the reprogramming efficiency and better understand the process, we sought to identify factors that mediate reprogramming with higher efficiency. We established an assay to screen nuclear fractions from extracts of pluripotent mouse cells based on Oct4 reactivation. Using proteomics, we identified components of the ATP-dependent BAF chromatin-remodeling complex, which significantly increases reprogramming efficiency when used together with the four factors. The reprogrammed cells could transmit to the germline and exhibited pluripotency. Reprogramming remained highly efficient when c-Myc was not present but BAF components were overexpressed. BAF complex components mediate this effect by facilitating enhanced Oct4 binding to target promoters during reprogramming. Thus, somatic cell reprogramming using chromatin-remodeling molecules represents an efficient method of generating reprogrammed cells

MSSM Electroweak Baryogenesis and Flavour Mixing in Transport Equations

We make use of the formalism developed in Ref. [1], and calculate the chargino mediated baryogenesis in the Minimal Supersymmetric Standard Model. The formalism makes use of a gradient expansion of the Kadanoff-Baym equations for mixing fermions. For illustrative purposes, we first discuss the semiclassical transport equations for mixing bosons in a space-time dependent Higgs background. To calculate the baryon asymmetry, we solve a standard set of diffusion equations, according to which the chargino asymmetry is transported to the top sector, where it biases sphaleron transitions. At the end we make a qualitative and quantitative comparison of our results with the existing work. We find that the production of the baryon asymmetry of the Universe by CP-violating currents in the chargino sector is strongly constrained by measurements of electric dipole moments.Comment: 30 pages, 6 figures; minor changes, published versio

The anaphase promoting complex impacts repair choice by protecting ubiquitin signalling at DNA damage sites

Double-strand breaks (DSBs) are repaired through two major pathways, homology-directed recombination (HDR) and non-homologous end joining (NHEJ). While HDR can only occur in S/G2, NHEJ can happen in all cell cycle phases (except mitosis). How then is the repair choice made in S/G2 cells? Here we provide evidence demonstrating that APCCdh1 plays a critical role in choosing the repair pathways in S/G2 cells. Our results suggest that the default for all DSBs is to recruit 53BP1 and RIF1. BRCA1 is blocked from being recruited to broken ends because its recruitment signal, K63-linked poly-ubiquitin chains on histones, is actively destroyed by the deubiquitinating enzyme USP1. We show that the removal of USP1 depends on APCCdh1 and requires Chk1 activation known to be catalysed by ssDNA-RPA-ATR signalling at the ends designated for HDR, linking the status of end processing to RIF1 or BRCA1 recruitment.We thank S.-Y. Lin (MD Anderson Cancer Center) for cell lines; J. Rosen (Baylor College of Medicine) for reagents; H. Masai (Tokyo Metropolitan Institute of Medical Science) for U2OS-Fucci cell line; D. Durocher (University of Toronto) for HeLa-Fucci cell line; E. Citterio (Netherlands Cancer Institute) for GFP-USP3 construct; M.S.Y. Huen (The University of Hong Kong) for RNF168 antibody. This work was performed with facilities and instruments in the Imaging Core of National Center for Protein Science (Beijing), the Cytometry and Cell Sorting Core at Baylor College of Medicine with funding from the NIH (P30 AI036211, P30 CA125123 and S10 RR024574), the Integrated Microscopy Core at Baylor College of Medicine with funding from the NIH (HD007495, DK56338 and CA125123), and the John S. Dunn Gulf Coast Consortium for Chemical Genomics. We also thank other members of the Zhang lab for helpful discussion and support. This work was supported in part by an international collaboration grant (# 2013DFB30210) and a 973 Project grant (# 2013CB910300) from Chinese Minister of Science and Technology, in part by a Chinese National Natural Science Foundation grant (# 81171920), in part by a grant from The Committee of Science and Technology of Beijing Municipality, China (# Z141100000214015), and in part by NIH grants CA116097 and CA122623 to P.Z. J.J. is supported by grants from National Institutes of Health (R01GM102529) and the Welch Foundation (AU-1711). S.H. is supported by grants (# 81272488 and 81472795) from Chinese National Natural Science Foundation. Y.Z. is supported by grants from the National Natural Scientific Foundation of China (No. 81430055), Programs for Changjiang Scholars and Innovative Research Team in University (No. IRT_15R13).S