6,815 research outputs found
Multi-mission Ni-H2 battery cell for the 1990's
A sufficient production, test and operational database is now available to permit design technology optimization for the next decade. The evolved battery cell design features standardized technology intended to support multiple type missions (e.g., both GEO and LEO). Design analyses and validation test cells demonstrate improved performance plus attractive specific-energy characteristics will be achieved
Multi-mission Ni-H2 battery cells for the 1990's
A sufficient production, test and operational database is now available to permit design technology optimization for the next decade. The evolved battery cell design features standardized technology intended to support multiple type missions (e.g., both GEO and LEO). Design analysis and validation test cells demonstrate that improved performance plus attractive specific-energy characteristics will be achieved
The implementation of a lossless data compression module in an advanced orbiting system: Analysis and development
Data compression has been proposed for several flight missions as a means of either reducing on board mass data storage, increasing science data return through a bandwidth constrained channel, reducing TDRSS access time, or easing ground archival mass storage requirement. Several issues arise with the implementation of this technology. These include the requirement of a clean channel, onboard smoothing buffer, onboard processing hardware and on the algorithm itself, the adaptability to scene changes and maybe even versatility to the various mission types. This paper gives an overview of an ongoing effort being performed at Goddard Space Flight Center for implementing a lossless data compression scheme for space flight. We will provide analysis results on several data systems issues, the performance of the selected lossless compression scheme, the status of the hardware processor and current development plan
Heterotopic gray matter in white matter in a 62 year old
"Heterotopia" describes normal cells in an abnormal location, and in the context of neurobiology, usually refers to neurons or gray matter in the leptomeninges or in periventricular or subcortical white matter, ("Gray Matter Heterotopia"). While once thought to be quite rare, the widespread MRI availability allowed increased recognition of these malformations. Clinically, gray matter heterotopias usually manifest as seizures in the first and second decades of life and may have associated motor and cognitive developmental disturbances. We report a patient with no known prior neurologic history, who developed seizures at the age of 62, which were subsequently determined to be from a subcortical gray matter heterotopia. The patient presented to an outside hospital with episodic confusion thought to represent partial seizures, and also numbness in her left foot, leg, and arm. MRI revealed a thickened corpus callosum and abnormal signal extending into the right cingulate gyrus white matter with an infiltrative appearance suggestive of a glioma or gliomatosis. Stereotactic biopsy demonstrated white matter containing irregular islands of synaptophysin-immunopositive gray matter within which there were large dysplastic neurons. This established a diagnosis of ectopic gray matter in the subcortical white matter. To our knowledge, this is the oldest age at which a person with this congenital condition has experienced onset of related symptoms
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Commentary: critical considerations for studying low-functioning autism
Jack and Pelphrey provide a systematic review of neuroimaging studies in understudied populations within the autistic spectrum, focussing specifically on those with minimal verbal ability, intellectual disability and developmental regression. Despite accounting for nearly a third of the autistic spectrum, the number of studies focussing on these populations is extremely low. This review highlights a critical need for further neuroimaging research on these populations, and provides practical suggestions for overcoming the challenges posed by it. In this commentary, I discuss some of the theoretical questions that arise from the review, on the conceptualisation of the autistic spectrum as well as on optimising experimental design and analysis
PRODUCTION AND PROFITABILITY RESPONSES TO ALTERNATIVE PROTEIN SOURCES AND LEVELS IN BROILER RATIONS
Profitability of using alternative protein sources in broiler feed is investigated through the development of a two-stage mathematical program that optimizes broiler production. A case study of peanut meal vs. soybean meal is examined. Value of marginal product concepts incorporated in this method permit analysis of demand adjustments before decisions on the production process occur. Given reported input and output prices, results indicate that soybean meal is generally more profitable than peanut meal. Peanut meal can be more profitable at higher dietary protein levels fed to broilers processed into whole carcass or at relatively higher prices for soybean meal.maximum profit, peanut meal, soybean meal, value of marginal product, Livestock Production/Industries, Q17,
Ternatin and improved synthetic variants kill cancer cells by targeting the elongation factor-1A ternary complex.
Cyclic peptide natural products have evolved to exploit diverse protein targets, many of which control essential cellular processes. Inspired by a series of cyclic peptides with partially elucidated structures, we designed synthetic variants of ternatin, a cytotoxic and anti-adipogenic natural product whose molecular mode of action was unknown. The new ternatin variants are cytotoxic toward cancer cells, with up to 500-fold greater potency than ternatin itself. Using a ternatin photo-affinity probe, we identify the translation elongation factor-1A ternary complex (eEF1A·GTP·aminoacyl-tRNA) as a specific target and demonstrate competitive binding by the unrelated natural products, didemnin and cytotrienin. Mutations in domain III of eEF1A prevent ternatin binding and confer resistance to its cytotoxic effects, implicating the adjacent hydrophobic surface as a functional hot spot for eEF1A modulation. We conclude that the eukaryotic elongation factor-1A and its ternary complex with GTP and aminoacyl-tRNA are common targets for the evolution of cytotoxic natural products
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