3,713 research outputs found
Central amygdala PKC-δ^+ neurons mediate the influence of multiple anorexigenic signals
Feeding can be inhibited by multiple cues, including those associated with satiety, sickness or unpalatable food. How such anorexigenic signals inhibit feeding at the neural circuit level is not completely understood. Although some inhibitory circuits have been identified, it is not yet clear whether distinct anorexigenic influences are processed in a convergent or parallel manner. The amygdala central nucleus (CEA) has been implicated in feeding control, but its role is controversial. The lateral subdivision of CEA (CEl) contains a subpopulation of GABAergic neurons that are marked by protein kinase C-δ (PKC-δ). We found that CEl PKC-δ^+ neurons in mice were activated by diverse anorexigenic signals in vivo, were required for the inhibition of feeding by such signals and strongly suppressed food intake when activated. They received presynaptic inputs from anatomically distributed neurons activated by different anorexigenic agents. Our data suggest that CEl PKC-δ^+ neurons constitute an important node that mediates the influence of multiple anorexigenic signals
Simulation of alnico coercivity
Micromagnetic simulations of alnico show substantial deviations from
Stoner-Wohlfarth behavior due to the unique size and spatial distribution of
the rod-like Fe-Co phase formed during spinodal decomposition in an external
magnetic field. The maximum coercivity is limited by single-rod effects,
especially deviations from ellipsoidal shape, and by interactions between the
rods. Both the exchange interaction between connected rods and magnetostatic
interaction between rods are considered, and the results of our calculations
show good agreement with recent experiments. Unlike systems dominated by
magnetocrystalline anisotropy, coercivity in alnico is highly dependent on
size, shape, and geometric distribution of the Fe-Co phase, all factors that
can be tuned with appropriate chemistry and thermal-magnetic annealing
In-Space Propulsion Technology Products for NASA's Future Science and Exploration Missions
Since 2001, the In-Space Propulsion Technology (ISPT) project has been developing and delivering in-space propulsion technologies that will enable or enhance NASA robotic science missions. These in-space propulsion technologies are applicable, and potentially enabling, for future NASA flagship and sample return missions currently being considered, as well as having broad applicability to future competed mission solicitations. The high-temperature Advanced Material Bipropellant Rocket (AMBR) engine providing higher performance for lower cost was completed in 2009. Two other ISPT technologies are nearing completion of their technology development phase: 1) NASA's Evolutionary Xenon Thruster (NEXT) ion propulsion system, a 0.6-7 kW throttle-able gridded ion system; and 2) Aerocapture technology development with investments in a family of thermal protection system (TPS) materials and structures; guidance, navigation, and control (GN&C) models of blunt-body rigid aeroshells; aerothermal effect models: and atmospheric models for Earth, Titan, Mars and Venus. This paper provides status of the technology development, applicability, and availability of in-space propulsion technologies that have recently completed their technology development and will be ready for infusion into NASA s Discovery, New Frontiers, Science Mission Directorate (SMD) Flagship, and Exploration technology demonstration mission
In-Space Propulsion Technology Products Ready for Infusion on NASA's Future Science Missions
Since 2001, the In-Space Propulsion Technology (ISPT) program has been developing and delivering in-space propulsion technologies that will enable or enhance NASA robotic science missions. These in-space propulsion technologies are applicable, and potentially enabling, for future NASA flagship and sample return missions currently being considered. They have a broad applicability to future competed mission solicitations. The high-temperature Advanced Material Bipropellant Rocket (AMBR) engine, providing higher performance for lower cost, was completed in 2009. Two other ISPT technologies are nearing completion of their technology development phase: 1) NASA s Evolutionary Xenon Thruster (NEXT) ion propulsion system, a 0.6-7 kW throttle-able gridded ion system; and 2) Aerocapture technology development with investments in a family of thermal protection system (TPS) materials and structures; guidance, navigation, and control (GN&C) models of blunt-body rigid aeroshells; aerothermal effect models; and atmospheric models for Earth, Titan, Mars and Venus. This paper provides status of the technology development, applicability, and availability of in-space propulsion technologies that have recently completed their technology development and will be ready for infusion into NASA s Discovery, New Frontiers, SMD Flagship, or technology demonstration missions
Methemoglobinemia: An unusual cause of postoperative cyanosis
AbstractMethemoglobinemia, although rare, must be considered in surgical patients presenting with acute respiratory distress and cyanosis. We report two cases of methemoglobinemia in patients undergoing aortic reconstruction. The first patient developed methemoglobinemia while on a nitroglycerin infusion, and the second after receiving benzocaine spray before intubation. Both patients were treated with methylene blue and ascorbic acid, with resolution of their hypoxia and cyanosis. The pathophysiology, etiology, diagnosis, and treatment of methemoglobinemia are reviewed
Influence of ractopamine supplementation on Salmonella in feeder pigs
The objective of the current study was to determine the effect of ractopamine supplementation on gut populations and fecal shedding of Salmonella in growing pigs
Control of Stress-Induced Persistent Anxiety by an Extra-Amygdala Septohypothalamic Circuit
The extended amygdala has dominated research on the neural circuitry of fear and anxiety, but the septohippocampal axis also plays an important role. The lateral septum (LS) is thought to suppress fear and anxiety through its outputs to the hypothalamus. However, this structure has not yet been dissected using modern tools. The type 2 CRF receptor (Crfr2) marks a subset of LS neurons whose functional connectivity we have investigated using optogenetics. Crfr2^+ cells include GABAergic projection neurons that connect with the anterior hypothalamus. Surprisingly, we find that these LS outputs enhance stress-induced behavioral measures of anxiety. Furthermore, transient activation of Crfr2^+ neurons promotes, while inhibition suppresses, persistent anxious behaviors. LS Crfr2^+ outputs also positively regulate circulating corticosteroid levels. These data identify a subset of LS projection neurons that promote, rather than suppress, stress-induced behavioral and endocrinological dimensions of persistent anxiety states and provide a cellular point of entry to LS circuitry
Sample Return Propulsion Technology Development Under NASA's ISPT Project
Abstract In 2009, the In-Space Propulsion Technology (ISPT) program was tasked to start development of propulsion technologies that would enable future sample return missions. Sample return missions can be quite varied, from collecting and bringing back samples of comets or asteroids, to soil, rocks, or atmosphere from planets or moons. As a result, ISPT s propulsion technology development needs are also broad, and include: 1) Sample Return Propulsion (SRP), 2) Planetary Ascent Vehicles (PAV), 3) Multi-mission technologies for Earth Entry Vehicles (MMEEV), and 4) Systems/mission analysis and tools that focuses on sample return propulsion. The SRP area includes electric propulsion for sample return and low cost Discovery-class missions, and propulsion systems for Earth Return Vehicles (ERV) including transfer stages to the destination. Initially the SRP effort will transition ongoing work on a High-Voltage Hall Accelerator (HIVHAC) thruster into developing a full HIVHAC system. SRP will also leverage recent lightweight propellant-tanks advancements and develop flight-qualified propellant tanks with direct applicability to the Mars Sample Return (MSR) mission and with general applicability to all future planetary spacecraft. ISPT s previous aerocapture efforts will merge with earlier Earth Entry Vehicles developments to form the starting point for the MMEEV effort. The first task under the Planetary Ascent Vehicles (PAV) effort is the development of a Mars Ascent Vehicle (MAV). The new MAV effort will leverage past MAV analysis and technology developments from the Mars Technology Program (MTP) and previous MSR studies. This paper will describe the state of ISPT project s propulsion technology development for future sample return missions.1
936-86 Plasma Fibrinogen Level Predicts Severity of Intimal Thickening After Cardiac Transplantation
Diffuse atherosclerosis is the primary reason for late graft failure after cardiac transplantation. Because there is increasing evidence that imbalances in the hemostatic and fibrinolytic pathways are associated with allogeneic rejection, we hypothesized that atherothrombotic risk factors may contribute to accelerated atherosclerosis. We therefore prospectively evaluated the burden of coronary atherosclerosis by intravascular ultrasound (IVUS) in 20 patients and measured plasma fibrinogen (FGN). lipoprotein (a) (Lp(a)) and net fibrinolytic activity of plasma using a standard fibrin plate assay. Intimal thickening was quantified using IVUS by measuring the intimal index (li=intimal area/[intimal area+luminal area]) in 2–5 segments of the LAD using planimetry. The maximal Ii per patient was calculated and indexed to the time post-transplant (Mxli/Yr). FGN predicted severity of Mxli/Yr (r2=0.41, p=0.008). In patients with decreased plasma fibrinolytic activity (lytic zone <100 mm2). Mxli/Yr was increased ten-fold (0.21±0.17 vs. 0.02±0.02, p=0.002). Because Lp(a) colocalizes with fibrinogen in the vessel wall and inhibits fibrinolysis, we correlated plasma Lp(a) levels with the degree of intimal thickening. Lp(a) did not predict Mxli/Yr (p=NS). In conclusion, these data suggest that plasma FGN and net fibrinolytic activity predict the degree of intimal thickening and that fibrin deposition may play an integral role in diffuse coronary atherosclerosis after cardiac transplantation
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