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  • 1
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    Lethargus is a Caenorhabditis elegans sleep-like state (2008)
    Nature Publishing Group (NPG)
    Details
    Publication Date: 2008-01-11
    Description: There are fundamental similarities between sleep in mammals and quiescence in the arthropod Drosophila melanogaster, suggesting that sleep-like states are evolutionarily ancient. The nematode Caenorhabditis elegans also has a quiescent behavioural state during a period called lethargus, which occurs before each of the four moults. Like sleep, lethargus maintains a constant temporal relationship with the expression of the C. elegans Period homologue LIN-42 (ref. 5). Here we show that quiescence associated with lethargus has the additional sleep-like properties of reversibility, reduced responsiveness and homeostasis. We identify the cGMP-dependent protein kinase (PKG) gene egl-4 as a regulator of sleep-like behaviour, and show that egl-4 functions in sensory neurons to promote the C. elegans sleep-like state. Conserved effects on sleep-like behaviour of homologous genes in C. elegans and Drosophila suggest a common genetic regulation of sleep-like states in arthropods and nematodes. Our results indicate that C. elegans is a suitable model system for the study of sleep regulation. The association of this C. elegans sleep-like state with developmental changes that occur with larval moults suggests that sleep may have evolved to allow for developmental changes.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Raizen, David M -- Zimmerman, John E -- Maycock, Matthew H -- Ta, Uyen D -- You, Young-jai -- Sundaram, Meera V -- Pack, Allan I -- England -- Nature. 2008 Jan 31;451(7178):569-72. doi: 10.1038/nature06535. Epub 2008 Jan 9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Center for Sleep and Respiratory Neurobiology, University of Pennsylvania School of Medicine, 3400 Spruce Street, Philadelphia, Pennsylvania 19104, USA. raizen@mail.med.upenn.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18185515" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Arousal/genetics/physiology ; Biological Evolution ; Caenorhabditis elegans/enzymology/genetics/*physiology ; Caenorhabditis elegans Proteins/genetics/metabolism ; Conserved Sequence/genetics ; Cyclic GMP-Dependent Protein Kinases/genetics/metabolism ; Drosophila melanogaster/genetics/physiology ; Homeostasis/physiology ; Larva/physiology ; Lethargy ; Molting/physiology ; Sleep/genetics/*physiology
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Nature Publishing Group (NPG)
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  • 2
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    Differential lysosomal proteolysis in antigen-presenting cells determines antigen fate (2005)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2005-03-12
    Description: Antigen-presenting cells (APCs) internalize antigens and present antigen-derived peptides to T cells. Although APCs have been thought to exhibit a well-developed capacity for lysosomal proteolysis, here we found that they can exhibit two distinct strategies upon antigen encounter. Whereas macrophages contained high levels of lysosomal proteases and rapidly degraded internalized proteins, dendritic cells (DCs) and B lymphocytes were protease-poor, resulting in a limited capacity for lysosomal degradation. Consistent with these findings, DCs in vivo degraded internalized antigens slowly and thus retained antigen in lymphoid organs for extended periods. Limited lysosomal proteolysis also favored antigen presentation. These results help explain why DCs are able to efficiently accumulate, process, and disseminate antigens and microbes systemically for purposes of tolerance and immunity.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Delamarre, Lelia -- Pack, Margit -- Chang, Henry -- Mellman, Ira -- Trombetta, E Sergio -- R37-AI34098/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 2005 Mar 11;307(5715):1630-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cell Biology and Department of Immunobiology, Ludwig Institute for Cancer Research, Yale University School of Medicine, 333 Cedar Street, Post Office Box 208002, New Haven, CT 06520-8002, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15761154" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; *Antigen Presentation ; Antigen-Presenting Cells/*enzymology/*immunology/metabolism ; Antigens/*metabolism ; B-Lymphocytes/enzymology/immunology/metabolism ; Cells, Cultured ; Dendritic Cells/*enzymology/immunology/metabolism ; Endocytosis ; Green Fluorescent Proteins/immunology/metabolism ; Histocompatibility Antigens Class II/immunology ; Horseradish Peroxidase/immunology/metabolism ; Lymphoid Tissue/cytology/enzymology/immunology ; Lysosome-Associated Membrane Glycoproteins ; Lysosomes/*enzymology/ultrastructure ; Macrophages/enzymology/immunology/metabolism ; Membrane Glycoproteins/metabolism ; Mice ; Mice, Inbred C3H ; Peptide Hydrolases/*metabolism ; Ribonuclease, Pancreatic/immunology/metabolism ; Ribonucleases/immunology/metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
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  • 3
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    High-Lift System for a Supercritical Airfoil: Simplified by Active Flow Control (2007)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Active flow control wind tunnel experiments were conducted in the NASA Langley Low-Turbulence Pressure Tunnel using a two-dimensional supercritical high-lift airfoil with a 15% chord hinged leading-edge flap and a 25% chord hinged trailing-edge flap. This paper focuses on the application of zero-net-mass-flux periodic excitation near the airfoil trailing edge flap shoulder at a Mach number of 0.1 and chord Reynolds numbers of 1.2 x 10(exp 6) to 9 x 10(exp 6) with leading- and trailing-edge flap deflections of 25 deg. and 30 deg., respectively. The purpose of the investigation was to increase the zero-net-mass-flux options for controlling trailing edge flap separation by using a larger model than used on the low Reynolds number version of this model and to investigate the effect of flow control at higher Reynolds numbers. Static and dynamic surface pressures and wake pressures were acquired to determine the effects of flow control on airfoil performance. Active flow control was applied both upstream of the trailing edge flap and immediately downstream of the trailing edge flap shoulder and the effects of Reynolds number, excitation frequency and amplitude are presented. The excitations around the trailing edge flap are then combined to control trailing edge flap separation. The combination of two closely spaced actuators around the trailing-edge flap knee was shown to increase the lift produced by an individual actuator. The phase sensitivity between two closely spaced actuators seen at low Reynolds number is confirmed at higher Reynolds numbers. The momentum input required to completely control flow separation on the configuration was larger than that available from the actuators used.
    Keywords: Aircraft Design, Testing and Performance
    Type: AIAA Paper 2007-0707 , 45th AIAA Aerospace Sciences Meeting and Exhibit; Jan 08, 2007 - Jan 11, 2007; Reno, NV; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
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