2,358 research outputs found
The mode of action of a lipid mobilising factor in cancer cachexia
Cachexia is characterised by a progressive weight loss due to depletion of both skeletal muscle and adipose tissue. The loss of adipose tissue is due to the production of a tumour-derived lipid mobilising factor (LMF), which has been shown to directly induce lipolysis in isolated epididymal murine white adipocytes. The administration of LMF to a non-tumour bearing mice produced a rapid weight loss, with a specific reduction in carcass lipid with also some redistribution of lipid with the accumulation of lipid in the liver. There was also up-regulation of uncoupling protein-1 and -2 mRNA and protein expression in brown adipose tissue, suggesting that an adaptive process occurs due to increased energy mobilisation. There was also up-regulation of UCP-2 in the livers of LMF treated mice, suggesting a protective mechanism to the build up of lipid in the livers, which would produce free radical by-products. LMF was also shown to stimulate cyclic AMP production in CHO-K1 cells transfected with human -3 adrenergic receptors and inhibited by the -β3 antagonist SR59230A. LMF binding was also inhibited by SR59230A in isolated receptors. This suggests that LMF mediates its effects through a β3 adrenergic receptor. There were also changes in glucose and fatty acid uptake in LMF treated mice, which suggests metabolic changes are occurring. The study suggests that a tumour derived lipolytic factor acts through the 3 adrenoceptor producing effects on lipid mobilisation, energy expenditure and glucose metabolism
Entangling the optical frequency comb: simultaneous generation of multiple 2x2 and 2x3 continuous-variable cluster states in a single optical parametric oscillator
We report on our research effort to generate large-scale multipartite
optical-mode entanglement using as few physical resources as possible. We have
previously shown that cluster- and GHZ-type N-partite continuous-variable
entanglement can be obtained in an optical resonator that contains a suitably
designed second-order nonlinear optical medium, pumped by at most O(N^2)
fields. In this paper, we show that the frequency comb of such a resonator can
be entangled into an arbitrary number of independent 2x2 and 2x3
continuous-variable cluster states by a single optical parametric oscillator
pumped by just a few optical modes.Comment: Third version has corrected eqs. (10-14) and revised notation "Q" in
lieu of "X" for amplitude quadrature operato
Time Frequency Analysis of Spacecraft Propellant Tank Spinning Slosh
Many spacecraft are designed to spin about an axis along the flight path as a means of stabilizing the attitude of the spacecraft via gyroscopic stiffness. Because of the assembly requirements of the spacecraft and the launch vehicle, these spacecraft often spin about an axis corresponding to a minor moment of inertia. In such a case, any perturbation of the spin axis will cause sloshing motions in the liquid propellant tanks that will eventually dissipate enough kinetic energy to cause the spin axis nutation (wobble) to grow further. This spinning slosh and resultant nutation growth is a primary design problem of spinning spacecraft and one that is not easily solved by analysis or simulation only. Testing remains the surest way to address spacecraft nutation growth. This paper describes a test method and data analysis technique that reveal the resonant frequency and damping behavior of liquid motions in a spinning tank. Slosh resonant frequency and damping characteristics are necessary inputs to any accurate numerical dynamic simulation of the spacecraft
Factors Influencing Willingness-to-Pay for the Energy Star Label
In the United States, nearly 17 percent of greenhouse gas emissions come from residential energy use. Increases in energy efficiency for the residential sector can generate significant energy savings and emissions reductions. Consumer labels, such as USEPA’s Energy Star, promote conservation by providing consumers with information on energy usage for household appliances. This study examines how the Energy Star label affects consumer preferences for refrigerators. An online survey of a national sample of adults suggest that consumers are, on average, willing to pay an extra 349.30 for a refrigerator that has been awarded the Energy Star label. Furthermore, the results provide evidence that willingness to pay was motivated by both private (energy cost savings) and public (environmental) benefits.Energy Star, willingness-to-pay, eco-label, Consumer/Household Economics, Demand and Price Analysis, Environmental Economics and Policy,
Playing the quantum harp: Multipartite squeezing and entanglement of harmonic oscillators
The frequency comb of an optical resonator is a naturally large set of exquisitely well defined quantum systems, such as in the broadband mode-locked lasers which have redefined time/frequency metrology and ultraprecise measurements in recent years. High coherence can therefore be expected in the quantum version of the frequency comb, in which nonlinear interactions couple different cavity modes, as can be modeled by different forms of graph states. We show that is possible to thereby generate states of interest to quantum metrology and computing, such as multipartite entangled cluster and Greenberger-Horne-Zeilinger states
Phase transitions near black hole horizons
The Reissner-Nordstrom black hole in four dimensions can be made unstable
without violating the dominant energy condition by introducing a real massive
scalar with non-renormalizable interactions with the gauge field. New stable
black hole solutions then exist with greater entropy for fixed mass and charge
than the Reissner-Nordstrom solution. In these new solutions, the scalar
condenses to a non-zero value near the horizon. Various generalizations of
these hairy black holes are discussed, and an attempt is made to characterize
when black hole hair can occur.Comment: 30 pages, 6 figures. v2: minor corrections, references adde
Safeguard: Progress and Test Results for a Reliable Independent On-Board Safety Net for UAS
As demands increase to use unmanned aircraft systems (UAS) for a broad spectrum of commercial applications, regulatory authorities are examining how to safely integrate them without compromising safety or disrupting traditional airspace operations. For small UAS, several operational rules have been established; e.g., do not operate beyond visual line-of-sight, do not fly within five miles of a commercial airport, do not fly above 400 feet above ground level. Enforcing these rules is challenging for UAS, as evidenced by the number of incident reports received by the Federal Aviation Administration (FAA). This paper reviews the development of an onboard system - Safeguard - designed to monitor and enforce conformance to a set of operational rules defined prior to flight (e.g., geospatial stay-out or stay-in regions, speed limits, and altitude constraints). Unlike typical geofencing or geo-limitation functions, Safeguard operates independently of the off-the-shelf UAS autopilot and is designed in a way that can be realized by a small set of verifiable functions to simplify compliance with existing standards for safety-critical systems (e.g. for spacecraft and manned commercial transportation aircraft systems). A framework is described that decouples the system from any other devices on the UAS as well as introduces complementary positioning source(s) for applications that require integrity and availability beyond what can be provided by the Global Positioning System (GPS). This paper summarizes the progress and test results for Safeguard research and development since presentation of the design concept at the 35th Digital Avionics Systems Conference (DASC '16). Significant accomplishments include completion of software verification and validation in accordance with NASA standards for spacecraft systems (to Class B), development of improved hardware prototypes, development of a simulation platform that allows for hardware-in-the-loop testing and fast-time Monte Carlo evaluations, and flight testing on multiple air vehicles. Integration testing with NASA's UAS Traffic Management (UTM) service-oriented architecture was also demonstrated
Intravenous Prenatal Nicotine Exposure Alters METH-Induced Hyperactivity, Conditioned Hyperactivity, and BDNF in Adult Rat Offspring
In the USA, approximately 15% of women smoke tobacco cigarettes during pregnancy. In utero tobacco smoke exposure produces somatic growth deficits like intrauterine growth restriction and low birth w
Role of β-adrenergic receptors in the oral activity of zinc-α2-glycoprotein (ZAG)
Zinc-a2-glycoprotein (ZAG) is an adipokine with the potential as a therapeutic agent in the treatment of obesity and type 2 diabetes. In this study we show that human ZAG, which is a 41-kDa protein, when administered to ob/ob mice at 50 µg/d-1 orally in the drinking water produced a progressive loss of body weight (5 g after 8 d treatment), together with a 0.5 C increase in rectal temperature and a 40% reduction in urinary excretion of glucose. There was also a 33% reduction in the area under the curve during an oral glucose tolerance test and an increased sensitivity to insulin. These results were similar to those after iv administration of ZAG. However, tryptic digestion was shown to inactivate ZAG. There was no evidence of human ZAG in the serum but a 2-fold elevation of murine ZAG, which was also observed in target tissues such as white adipose tissue. To determine whether the effect was due to interaction of the human ZAG with the ß-adrenergic (ß-AR) in the gastrointestinal tract before digestion, ZAG was coadministered to ob/ob mice together with propanolol (40 mg/kg-1), a nonspecific ß-AR antagonist. The effect of ZAG on body weight, rectal temperature, urinary glucose excretion, improvement in glucose disposal, and increased insulin sensitivity were attenuated by propanolol, as was the increase in murine ZAG in the serum. These results suggest that oral administration of ZAG increases serum levels through interaction with a ß-AR in the upper gastrointestinal tract, and gene expression studies showed this to be in the esophagus
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