1,009 research outputs found

    A method of visualization of Neurospora nucleosidase in polyacrylamide gels

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    Visualization of nucleosidase in polyacrylamide gel

    Experimental Milestones in the Discovery of Molecular Chaperones as Polypeptide Unfolding Enzymes.

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    Molecular chaperones control the cellular folding, assembly, unfolding, disassembly, translocation, activation, inactivation, disaggregation, and degradation of proteins. In 1989, groundbreaking experiments demonstrated that a purified chaperone can bind and prevent the aggregation of artificially unfolded polypeptides and use ATP to dissociate and convert them into native proteins. A decade later, other chaperones were shown to use ATP hydrolysis to unfold and solubilize stable protein aggregates, leading to their native refolding. Presently, the main conserved chaperone families Hsp70, Hsp104, Hsp90, Hsp60, and small heat-shock proteins (sHsps) apparently act as unfolding nanomachines capable of converting functional alternatively folded or toxic misfolded polypeptides into harmless protease-degradable or biologically active native proteins. Being unfoldases, the chaperones can proofread three-dimensional protein structures and thus control protein quality in the cell. Understanding the mechanisms of the cellular unfoldases is central to the design of new therapies against aging, degenerative protein conformational diseases, and specific cancers

    Influence of sodium pyruvate on Neurospora fructose diphosphatase

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    Influence of sodium pyruvate on fructose diphosphatas

    Mediated control of polyphosphotase in Neurospora crassa

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    Phosphate-mediated control of polyphosphate in Neurospora crass

    Applying the Dark Target Aerosol Algorithm with Advanced Himawari Imager Observations During the KORUS-AQ Field Campaign

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    For nearly 2 decades we have been quantitatively observing the Earth's aerosol system from space at one or two times of the day by applying the Dark Target family of algorithms to polar-orbiting satellite sensors, particularly MODIS and VIIRS. With the launch of the Advanced Himawari Imager (AHI) and the Advanced Baseline Imagers (ABIs) into geosynchronous orbits, we have the new ability to expand temporal coverage of the traditional aerosol optical depth (AOD) to resolve the diurnal signature of aerosol loading during daylight hours. The KoreanUnited States Air Quality (KORUS-AQ) campaign taking place in and around the Korean peninsula during MayJune 2016 initiated a special processing of full-disk AHI observations that allowed us to make a preliminary adoption of Dark Target aerosol algorithms to the wavelengths and resolutions of AHI. Here,we describe the adaptation and show retrieval results from AHI for this 2-month period. The AHI-retrieved AOD is collocated in time and space with existing AErosol RObotic NETwork stations across Asia and with collocated Terra and Aqua MODIS retrievals. The new AHI AOD product matches AERONET, and the standard MODIS product does as well, and the agreement between AHI and MODIS retrieved AOD is excellent, as can be expected by maintaining consistency in algorithm architecture and most algorithm assumptions. Furthermore, we show that the new product approximates the AERONET-observed diurnal signature. Examining the diurnal patterns of the new AHI AOD product we find specific areas over land where the diurnal signal is spatially cohesive. For example, in Bangladesh the AOD in-creases by 0.50 from morning to evening, and in northeast China the AOD decreases by 0.25. However, over open ocean the observed diurnal cycle is driven by two artifacts, one associated with solar zenith angles greater than 70t hat may be caused by a radiative transfer model that does not properly represent the spherical Earth and the other artifact associated with the fringes of the 40 degree glint angle mask. This opportunity during KORUS-AQ provides encouragement to move towards an operational Dark Target algorithm for AHI. Future work will need to re-examine masking including snow mask, reevaluate assumed aerosol models for geosynchronous geometry, address the artifacts over the ocean, and investigate size parameter retrieval from the over-ocean algorithm

    MODIS 3km Aerosol Product: Algorithm and Global Perspective

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    After more than a decade of producing a nominal 10 km aerosol product based on the dark target method, the MODIS aerosol team will be releasing a nominal 3 km product as part of their Collection 6 release. The new product differs from the original 10 km product only in the manner in which reflectance pixels are ingested, organized and selected by the aerosol algorithm. Overall, the 3 km product closely mirrors the 10 km product. However, the finer resolution product is able to retrieve over ocean closer to islands and coastlines, and is better able to resolve fine aerosol features such as smoke plumes over both ocean and land. In some situations, it provides retrievals over entire regions that the 10 km product barely samples. In situations traditionally difficult for the dark target algorithm, such as over bright or urban surfaces the 3 km product introduces isolated spikes of artificially high aerosol optical depth (AOD) that the 10 km algorithm avoids. Over land, globally, the 3 km product appears to be 0.01 to 0.02 higher than the 10 km product, while over ocean, the 3 km algorithm is retrieving a proportionally greater number of very low aerosol loading situations. Based on collocations with ground-based observations for only six months, expected errors associated with the 3 km land product are determined to be greater than for the 10 km product: 0.05 0.25 AOD. Over ocean, the suggestion is for expected errors to be the same as the 10 km product: 0.03 0.05 AOD. The advantage of the product is on the local scale, which will require continued evaluation not addressed here. Nevertheless, the new 3 km product is expected to provide important information complementary to existing satellite-derived products and become an important tool for the aerosol community
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