317,293 research outputs found

    Rivalry, Exclusion and Coalitions

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    Coalition formation, exclusion contest, tragedy of the commons

    A Leptin-regulated Circuit Controls Glucose Mobilization During Noxious Stimuli

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    Adipocytes secrete the hormone leptin to signal the sufficiency of energy stores. Reductions in circulating leptin concentrations reflect a negative energy balance, which augments sympathetic nervous system (SNS) activation in response to metabolically demanding emergencies. This process ensures adequate glucose mobilization despite low energy stores. We report that leptin receptor–expressing neurons (LepRb neurons) in the periaqueductal gray (PAG), the largest population of LepRb neurons in the brain stem, mediate this process. Application of noxious stimuli, which often signal the need to mobilize glucose to support an appropriate response, activated PAG LepRb neurons, which project to and activate parabrachial nucleus (PBN) neurons that control SNS activation and glucose mobilization. Furthermore, activating PAG LepRb neurons increased SNS activity and blood glucose concentrations, while ablating LepRb in PAG neurons augmented glucose mobilization in response to noxious stimuli. Thus, decreased leptin action on PAG LepRb neurons augments the autonomic response to noxious stimuli, ensuring sufficient glucose mobilization during periods of acute demand in the face of diminished energy stores

    Photosensitive Sacrificial Polymer With Low Residue

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    Embodiments according to the present invention relate generally to PAG bilayer and PAG-doped unilayer structures using sacrificial polymer layers that incorporate a photoacid generator having a concentration gradient therein. Said PAG concentration being higher in a upper portion of such structures than in a lower portion thereof. Embodiments according to the present invention also relate to a method of using such bilayers and unilayers to form microelectronic structures having a three-dimensional space, and methods of decomposition of the sacrificial polymer within the aforementioned layers.Georgia Tech Research Corporatio

    Polymer Bound Photobase Generators And Photoacid Generators For Pitch Division Lithography

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    The semiconductor industry is pursuing several process options that provide pathways to printing images smaller than the theoretical resolution limit of 193 nm projection scanners. These processes include double patterning, side wall deposition and pitch division. Pitch doubling lithography (PDL), the achievement of pitch division by addition of a photobase generator (PBG) to typical 193 nm resist formulations was recently presented. 1 Controlling the net acid concentration as a function of dose by incorporating both a photoacid generator (PAG) and a PBG in the resist formulation imparts a resist dissolution rate response modulation at twice the frequency of the aerial image. Simulation and patterning of 45 nm half pitch L/S patterns produced using a 90 nm half pitch mask were reported. 2 Pitch division was achieved, but the line edge roughness of the resulting images did not meet the current standard. To reduce line edge roughness, polymer bound PBGs and polymer bound PAGs were investigated in the PDL resist formulations. The synthesis, purification, analysis, and functional performance of various polymers containing PBG or PAG monomers are described herein. Both polymer bound PBG with monomeric PAG and polymer bound PAG with monomeric PBG showed a PDL response. The performance of the polymer bound formulations is compared to the same formulations with small molecule analogs of PAG and PBG.Chemical Engineerin

    Septic Systems Discussion Session

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    Cruise Report 74-KB-1: Lobster investigations

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    Cover Art

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    Cruise Report 73-KB-27: Big game fish investigations

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