1,858 research outputs found

    Temperature and Carbon Assimilation Regulate the Chlorosome Biogenesis in Green Sulfur Bacteria

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    Green photosynthetic bacteria adjust the structure and functionality of the chlorosome—the light-absorbing antenna complex—in response to environmental stress factors. The chlorosome is a natural self-assembled aggregate of bacteriochlorophyll (BChl) molecules. In this study, we report the regulation of the biogenesis of the Chlorobaculum tepidum chlorosome by carbon assimilation in conjunction with temperature changes. Our studies indicate that the carbon source and thermal stress culture of C. tepidum grows slower and incorporates fewer BChl c in the chlorosome. Compared with the chlorosome from other cultural conditions we investigated, the chlorosome from the carbon source and thermal stress culture displays (a) smaller cross-sectional radius and overall size, (b) simplified BChl c homologs with smaller side chains, (c) blue-shifted QyQ_y absorption maxima, and (d) a sigmoid-shaped circular dichroism spectra. Using a theoretical model, we analyze how the observed spectral modifications can be associated with structural changes of BChl aggregates inside the chlorosome. Our report suggests a mechanism of metabolic regulation for chlorosome biogenesis.Chemistry and Chemical Biolog

    Full counting statistics of information content

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    We review connections between the cumulant generating function of full counting statistics of particle number and the R\'enyi entanglement entropy. We calculate these quantities based on the fermionic and bosonic path-integral defined on multiple Keldysh contours. We relate the R\'enyi entropy with the information generating function, from which the probability distribution function of self-information is obtained in the nonequilibrium steady state. By exploiting the distribution, we analyze the information content carried by a single bosonic particle through a narrow-band quantum communication channel. The ratio of the self-information content to the number of bosons fluctuates. For a small boson occupation number, the average and the fluctuation of the ratio are enhanced.Comment: 16 pages, 5 figure

    Real-time 100 Gbps/λ/core NRZ and EDB IM/DD transmission over multicore fiber for intra-datacenter communication networks

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    A BiCMOS chip-based real-time intensity modulation/direct detection spatial division multiplexing system is experimentally demonstrated for both optical interconnects. 100 Gbps/lambda/core electrical duobinary (EDB) transmission over 1 km 7-core multicore fiber (MCF) is carried out, achieving KP4 forward error correction (FEC) limit (BER < 2E-4). Using optical dispersion compensation, 7 x 100 Gbps/lambda/core transmission of both non-retunito-zero (NRZ) and EDB signals over 10 km MCF transmission is achieved with BER lower than 7% overhead hard-decision FEC limit (BER < 3.8E-3). The integrated low complexity transceiver IC and analog signal processing approach make such a system highly attractive for the high-speed intra-datacenter interconnects. (C) 2018 Optical Society of America under the terms oldie OSA open Access Publishing Agreement

    Concerted IL-25R and IL-4Rα signaling drive innate type 2 effector immunity for optimal helminth expulsion

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    Interleukin 25 (IL-25) is a major 'alarmin' cytokine, capable of initiating and amplifying the type 2 immune response to helminth parasites. However its role in the later effector phase of clearing chronic infection remains unclear. The helminth Heligmosomoides polygyrus establishes long-term infections in susceptible C57BL/6 mice, but is slowly expelled in BALB/c mice from day 14 onwards. We noted that IL-25R (Il17rb)-deficient BALB/c mice were unable to expel parasites despite type 2 immune activation comparable to the wild-type. We then established that in C57BL/6 mice, IL-25 adminstered late in infection (days 14-17) drove immunity. Moreover when IL-25 and IL-4 were delivered to Rag1-deficient mice, the combination resulted in near complete expulsion of the parasite, even following administration of an anti-CD90 antibody to deplete innate lymphoid cells (ILCs). Hence, effective anti-helminth immunity during chronic infection requires an innate effector cell population that is synergistically activated by the combination of IL-4Rα and IL-25R signaling

    Aligning ancient and modern approaches to sustainable urban water management in China: Ningbo as a ‘Blue-Green City’ in the ‘Sponge City’ Campaign

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    Modern urban flood and water management emphasises holistic strategies that reduce flood risk while providing co- benefits to urban economies, societies and environments. The ‘Blue‐Green City’ concept provides a viable framework for putting this into practice. Ningbo, is a coastal city with high flood risk, whose history as a Chinese ‘water town’ demonstrates that approaches to water management implicit to the ‘Blue‐Green’ concept were practiced in ancient times, and lessons can be learned from these applications. Furthermore, recent launch of the ‘Sponge City’ campaign by China's National Government demonstrates the political will to implement sustainable flood and water management in ways consistent with the ‘Blue‐Green’ ideals. Selection of Ningbo for a pilot project presents the opportunity to integrate new ‘Sponge city’ approaches with ancient ‘Blue‐Green’ principles, within the contexts of both new urban development and retrofit. Reinventing traditional approaches to urban water management and governance offers the possibility of maintaining flood risk at acceptable levels without constraining urban growth in China and other countries experiencing rapid urban development
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