212 research outputs found

    Passing crisis and emergency risk communications: the effects of communication channel, information type, and repetition.

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    Three experiments explore several factors which influence information transmission when warning messages are passed from person to person. In Experiment 1, messages were passed down chains of participants using five different modes of communication. Written communication channels resulted in more accurate message transmission than verbal. In addition, some elements of the message endured further down the chain than others. Experiment 2 largely replicated these effects and also demonstrated that simple repetition of a message eliminated differences between written and spoken communication. In a final field experiment, chains of participants passed information however they wanted to, with the proviso that half of the chains could not use telephones. Here, the lack of ability to use a telephone did not affect accuracy, but did slow down the speed of transmission from the recipient of the message to the last person in the chain. Implications of the findings for crisis and emergency risk communication are discussed

    IMAC capture of recombinant protein from unclarified mammalian cell feed streams

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    Fusion-tag affinity chromatography is a key technique in recombinant protein purification. Current methods for protein recovery from mammalian cells are hampered by the need for feed stream clarification. We have developed a method for direct capture using immobilized metal affinity chromatography (IMAC) of hexahistidine (His6) tagged proteins from unclarified mammalian cell feed streams. The process employs radial flow chromatography with 300-500 μm diameter agarose resin beads that allow free passage of cells but capture His-tagged proteins from the feed stream; circumventing expensive and cumbersome centrifugation and/or filtration steps. The method is exemplified by Chinese Hamster Ovary (CHO) cell expression and subsequent recovery of recombinant His-tagged carcinoembryonic antigen (CEA); a heavily glycosylated and clinically relevant protein. Despite operating at a high NaCl concentration necessary for IMAC binding, cells remained over 96% viable after passage through the column with host cell proteases and DNA detected at ∼8 U/mL and 2 ng/μL in column flow-through, respectively. Recovery of His-tagged CEA from unclarified feed yielded 71% product recovery. This work provides a basis for direct primary capture of fully glycosylated recombinant proteins from unclarified mammalian cell feed streams. Biotechnol. Bioeng. 2015;9999: 1-11. © 2015 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc

    Multi-dimensional synthetic space and state measurement with spectral photonic lattices

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    © OSA 2018. We propose and experimentally realize spectral photonic lattices with pumpinduced frequency couplings, which can emulate multi-dimensional dynamics with synthetic gauge fields and enable single-shot measurement of the signal phase and coherence

    Scalable multi-dimensional synthetic space and full state reconstruction in spectral lattices

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    © 2018 The Author(s). We propose and experimentally realize spectral photonic lattices with pumpinduced frequency couplings, which can emulate multi-dimensional dynamics with synthetic gauge fields and enable single-shot measurement of the signal phase and coherence

    A scale-down mimic for mapping the process performance of centrifugation, depth and sterile filtration

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    In the production of biopharmaceuticals disk-stack centrifugation is widely used as a harvest step for the removal of cells and cellular debris. Depth filters followed by sterile filters are often then employed to remove residual solids remaining in the centrate. Process development of centrifugation is usually conducted at pilot-scale so as to mimic the commercial scale equipment but this method requires large quantities of cell culture and significant levels of effort for successful characterization. A scale-down approach based upon the use of a shear device and a bench-top centrifuge has been extended in this work towards a preparative methodology that successfully predicts the performance of the continuous centrifuge and polishing filters. The use of this methodology allows the effects of cell culture conditions and large-scale centrifugal process parameters on subsequent filtration performance to be assessed at an early stage of process development where material availability is limited

    Quantum metasurface for multiphoton interference and state reconstruction

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    ©The Authors. Metasurfaces based on resonant nanophotonic structures have enabled innovative types of flat-optics devices that often outperform the capabilities of bulk components,yet these advances remain largely unexplored for quantum applications.We show that nonclassical multiphoton interferences can be achieved at the subwavelength scale in all-dielectric metasurfaces.We simultaneously image multiple projections of quantum states with a single metasurface,enabling a robust reconstruction of amplitude,phase,coherence, and entanglement of multiphoton polarization-encoded states.One-and two-photon states are reconstructed through nonlocal photon correlation measurements with polarizationinsensitive click detectors positioned after the metasurface, and the scalability to higher photon numbers is established theoretically.Our work illustrates the feasibility of ultrathin quantum metadevices for the manipulation and measurement of multiphoton quantum states,with applications in free-space quantum imaging and communications

    Quantum imaging with dielectric metasurfaces for multi-photon polarization tomography

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    © 2017 IEEE. We suggest and realize experimentally dielectric metasurfaces with high transmission efficiency for quantum multi-photon tomography, allowing for full reconstruction of pure or mixed quantum polarization states across a broad bandwidth

    Tomography of quantum dots in a non-hermitian photonic chip

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    © 2019 IEEE. Quantum optical information systems offer the potential for secure communication and fast quantum computation. To fully characterise a quantum optical system one has to use quantum tomography [1]. Integration of quantum optics onto photonic chips provides advantages such as miniaturisation and stability, and also significantly improves quantum tomography using both re-configurable [2], and more recently, simpler static designs [3,4]. These on-chip designs have, so far, only used probabilistic single photon sources. Here we are working towards quantum tomography using a true deterministic source - a quantum dot. The scheme of the proposed experiment is shown in Fig. 1A. So far we have fabricated and characterised the performance of an InGaAs quantum dot monolithically integrated into a microlens [5], and completed the design, fabrication and classical characterisation of a photonic chip for quantum tomography

    Phase-field modeling of microstructural pattern formation during directional solidification of peritectic alloys without morphological instability

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    During the directional solidification of peritectic alloys, two stable solid phases (parent and peritectic) grow competitively into a metastable liquid phase of larger impurity content than either solid phase. When the parent or both solid phases are morphologically unstable, i.e., for a small temperature gradient/growth rate ratio (G/vpG/v_p), one solid phase usually outgrows and covers the other phase, leading to a cellular-dendritic array structure closely analogous to the one formed during monophase solidification of a dilute binary alloy. In contrast, when G/vpG/v_p is large enough for both phases to be morphologically stable, the formation of the microstructurebecomes controlled by a subtle interplay between the nucleation and growth of the two solid phases. The structures that have been observed in this regime (in small samples where convection effect are suppressed) include alternate layers (bands) of the parent and peritectic phases perpendicular to the growth direction, which are formed by alternate nucleation and lateral spreading of one phase onto the other as proposed in a recent model [R. Trivedi, Metall. Mater. Trans. A 26, 1 (1995)], as well as partially filled bands (islands), where the peritectic phase does not fully cover the parent phase which grows continuously. We develop a phase-field model of peritectic solidification that incorporates nucleation processes in order to explore the formation of these structures. Simulations of this model shed light on the morphology transition from islands to bands, the dynamics of spreading of the peritectic phase on the parent phase following nucleation, which turns out to be characterized by a remarkably constant acceleration, and the types of growth morphology that one might expect to observe in large samples under purely diffusive growth conditions.Comment: Final version, minor revisions, 16 pages, 14 EPS figures, RevTe
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