5,095 research outputs found

    Characterization and evaluation of Bacillus isolates for their potential plant growth and biocontrol activities against tomato bacterial wilt

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    About 200 Bacillus isolates were isolated from tomato and potato rhizosphere and examined for their antagonistic activities against Ralstonia solanacearum T-91, the causal agent of tomato bacterial wilt (TBW), in vitro and in vivo. Four strains, AM1, D16, D29 and H8, have shown high potential of antagonistic activity against the pathogen in laboratory and greenhouse experiments. In greenhouse, 81.1 to 89.0% reduction of disease incidence of TBW was recorded in treated tomato plants with 4 isolates, which also significantly (p > 0.05) increased plant height by 22.7 to 43.7% and dry weight by 47.93 to 91.55% compared with non-treated control. 16SrRNA gene sequence, the biochemical and physiological tests and fatty acid methyl esters analysis assigned strains AM1 and D29 as Bacillus amyloliquefaciens, while strains D16 and H8 as Bacillus subtilis and B. methylotrophicus, respectively. In addition, the 4 strains showed ability to inhibit growth of the three soil-borne fungi, produce indole-3- acetic acid, siderophores and also with exception of strain D16, the other 3 strains were capable of solubilizing phosphate. Therefore, these results suggest that out of 200 isolates, Bacillus stains AM1, D16, D29 and H8 support good antagonistic activity and could be applied as biocontrol agents against TBW under greenhouse conditions beside their potential to promote tomato plants growth.Key words: Tomato, Ralstonia solanacearum, Bacillus spp, biological control, plant growth promotion activitie

    Recent progress in organic-based radiative cooling materials: fabrication methods and thermal management properties

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    Organic-based materials capable of radiative cooling have attracted widespread interest in recent years due to their ease of engineering and good adaptability to different application scenarios. As a cooling material for walls, clothing, and electronic devices, these materials can reduce the energy consumption load of air conditioning, improve thermal comfort, and reduce carbon emissions. In this paper, an overview is given of the current fabrication strategies of organic-based radiative cooling materials, and of their properties. The methods and joint thermal management strategies including evaporative cooling, phase-change materials, fluorescence, and light-absorbing materials that have been demonstrated in conjunction with a radiative cooling function are also discussed. This review provides a comprehensive overview of organic-based radiative cooling, exemplifying the emerging application directions in this field and highlighting promising future research directions in the field

    An invisibility cloak using silver nanowires

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    In this paper, we use the parameter retrieval method together with an analytical effective medium approach to design a well-performed invisible cloak, which is based on an empirical revised version of the reduced cloak. The designed cloak can be implemented by silver nanowires with elliptical cross-sections embedded in a polymethyl methacrylate host. This cloak is numerically proved to be robust for both the inner hidden object as well as incoming detecting waves, and is much simpler thus easier to manufacture when compared with the earlier proposed one [Nat. Photon. 1, 224 (2007)].Comment: 7 pages, 4 figures, 2 table

    PARP3 is a sensor of nicked nucleosomes and monoribosylates histone H2B(Glu2).

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    PARP3 is a member of the ADP-ribosyl transferase superfamily that we show accelerates the repair of chromosomal DNA single-strand breaks in avian DT40 cells. Two-dimensional nuclear magnetic resonance experiments reveal that PARP3 employs a conserved DNA-binding interface to detect and stably bind DNA breaks and to accumulate at sites of chromosome damage. PARP3 preferentially binds to and is activated by mononucleosomes containing nicked DNA and which target PARP3 trans-ribosylation activity to a single-histone substrate. Although nicks in naked DNA stimulate PARP3 autoribosylation, nicks in mononucleosomes promote the trans-ribosylation of histone H2B specifically at Glu2. These data identify PARP3 as a molecular sensor of nicked nucleosomes and demonstrate, for the first time, the ribosylation of chromatin at a site-specific DNA single-strand break

    Streamflow Forecast and Reservoir Operation Performance Assessment Under Climate Change

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    This study attempts to investigate potential impacts of future climate change on streamflow and reservoir operation performance in a Northern American Prairie watershed. System Dynamics is employed as an effective methodology to organize and integrate existing information available on climate change scenarios, watershed hydrologic processes, reservoir operation and water resource assessment system. The second version of the Canadian Centre for Climate Modelling and Analysis Coupled Global Climate Model is selected to generate the climate change scenarios with daily climatic data series for hydrologic modeling. Watershed-based hydrologic and reservoir water dynamics modeling focuses on dynamic processes of both streamflow generation driven by climatic conditions, and the reservoir water dynamics based on reservoir operation rules. The reliability measure describes the effectiveness of present reservoir operation rules to meet various demands which are assumed to remain constant for the next 100 years in order to focus the study on the understanding of the structure and the behaviour of the water supply. Simulation results demonstrate that future climate variation and change may bring more high-peak-streamflow occurrences and more abundant water resources. Current reservoir operation rules can provide a high reliability in drought protection and flood control

    Chromosomal Rearrangements between Serotype A and D Strains in Cryptococcus neoformans

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    Cryptococcus neoformans is a major human pathogenic fungus that can cause meningoencephalitis in immunocompromised hosts. It contains two divergent varieties, var. grubii (serotype A) and var. neoformans (serotype D), as well as hybrids (serotype AD) between these two varieties. In this study, we investigated the extent of chromosomal rearrangements between the two varieties, estimated the effects of chromosomal rearrangements on recombination frequencies, and surveyed the potential polymorphisms of the rearrangements among natural strains of the three serotypes. Through the analyses of two sequenced genomes from strains H99 (representing var. grubii) and JEC21 (representing var. neoformans), we revealed a total of 32 unambiguous chromosome rearrangements, including five translocations, nine simple inversions, and 18 complex rearrangements. Our analyses identified that overall, rearranged regions had recombination frequencies about half of those around syntenic regions. Using a direct PCR screening strategy, we examined the potential polymorphisms of 11 rearrangements among 64 natural C. neoformans strains from five countries. We found no polymorphism within var. neoformans and very limited polymorphism within var. grubii. However, strains of serotype AD showed significant polymorphism, consistent with their hybrid origins coupled with differential loss of heterozygosity. We discuss the implications of these results on the genome structure, ecology, and evolution of C. neoformans

    THz quantum cascade lasers operating on the radiative modes of a 2D photonic crystal

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    Photonic-crystal lasers operating on Γ-point band-edge states of a photonic structure naturally exploit the so-called “nonradiative” modes. As the surface output coupling efficiency of these modes is low, they have relatively high Q factors, which favor lasing. We propose a new 2D photonic-crystal design that is capable of reversing this mode competition and achieving lasing on the radiative modes instead. Previously, this has only been shown in 1D structures, where the central idea is to introduce anisotropy into the system, both at unit-cell and resonator scales. By applying this concept to 2D photonic-crystal patterned terahertz frequency quantum cascade lasers, surface-emitting devices with diffraction-limited beams are demonstrated, with 17 mW peak output power
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