1,844 research outputs found
Triglyceride-rich lipoproteins prevent septic death in rats.
Triglyceride-rich lipoproteins bind and inactive bacterial endotoxin in vitro and prevent death when given before a lethal dose of endotoxin in animals. However, lipoproteins have not yet been demonstrated to improve survival in polymicrobial gram-negative sepsis. We therefore tested the ability of triglyceride-rich lipoproteins to prevent death after cecal ligation and puncture (CLP) in rats. Animals were given bolus infusions of either chylomicrons (1 g triglyceride/kg per 4 h) or an equal volume of saline for 28 h after CLP. Chylomicron infusions significantly improved survival (measured at 96 h) compared with saline controls (80 vs 27%, P < or = 0.03). Chylomicron infusions also reduced serum levels of endotoxin, measured 90 min (26 +/- 3 vs 136 +/- 51 pg/ml, mean +/- SEM, P < or = 0.03) and 6 h (121 +/- 54 vs 1,026 +/- 459 pg/ml, P < or = 0.05) after CLP. The reduction in serum endotoxin correlated with a reduction in serum tumor necrosis factor, measured 6 h after CLP (0 +/- 0 vs 58 +/- 24 pg/ml, P < or = 0.03), suggesting that chylomicrons improve survival in this model by limiting macrophage exposure to endotoxin and thereby reducing secretion of inflammatory cytokines. Infusions of a synthetic triglyceride-rich lipid emulsion (Intralipid; KabiVitrum, Inc., Alameda, CA) (1 g triglyceride/kg) also significantly improved survival compared with saline controls (71 vs 27%, P < or = 0.03). These data demonstrate that triglyceride-rich lipoproteins can protect animals from lethal polymicrobial gram-negative sepsis
Parametric Evolution for a Deformed Cavity
We consider a classically chaotic system that is described by a Hamiltonian
H(Q,P;x), where (Q,P) describes a particle moving inside a cavity, and x
controls a deformation of the boundary. The quantum-eigenstates of the system
are |n(x)>. We describe how the parametric kernel P(n|m) = , also
known as the local density of states, evolves as a function of x-x0. We
illuminate the non-unitary nature of this parametric evolution, the emergence
of non-perturbative features, the final non-universal saturation, and the
limitations of random-wave considerations. The parametric evolution is
demonstrated numerically for two distinct representative deformation processes.Comment: 13 pages, 8 figures, improved introduction, to be published in Phys.
Rev.
Reduction of circulating cholesterol and apolipoprotein levels during sepsis
Sepsis with multiple organ failure is frequently associated with a substantial decrease of cholesterol levels. This decrease of cholesterol is strongly associated with mortality suggesting a direct relation between inflammatory conditions and altered cholesterol homeostasis. The host response during sepsis is mediated by cytokines and growth factors, which are capable of influencing lipid metabolism. Conversely lipoproteins are also capable of modulating cytokine production during the inflammatory response. Therefore the decrease in circulating cholesterol levels seems to play a crucial role in the pathophysiology of sepsis. In this review the interaction between cytokines and lipid metabolism and its clinical consequences will be discussed
Study of the growth parameters involved in synthesizing boron carbide filaments Final report
Boron carbide whiskers - growth, mechanical properties and crystalline perfection, and incorporation in composite material
Localization in Strongly Chaotic Systems
We show that, in the semiclassical limit and whenever the elements of the
Hamiltonian matrix are random enough, the eigenvectors of strongly chaotic
time-independent systems in ordered bases can on average be exponentially
localized across the energy shell and decay faster than exponentially outside
the energy shell. Typically however, matrix elements are strongly correlated
leading to deviations from such behavior.Comment: RevTeX, 5 pages + 3 postscript figures, submitted to Phys. Rev. Let
Quantum-Mechanical Non-Perturbative Response of Driven Chaotic Mesoscopic Systems
Consider a time-dependent Hamiltonian with periodic driving
. It is assumed that the classical dynamics is chaotic,
and that its power-spectrum extends over some frequency range
. Both classical and quantum-mechanical (QM) linear
response theory (LRT) predict a relatively large response for
, and a relatively small response otherwise, independently
of the driving amplitude . We define a non-perturbative regime in the
space, where LRT fails, and demonstrate this failure numerically.
For , where , the system may have a relatively
strong response for , and the shape of the response
function becomes dependent.Comment: 4 pages, 2 figures, revised version with much better introductio
Study of the growth parameters involved in synthesizing boron carbide filaments
Growth and deposition zone geometry effects on boron carbide whisker production, mechanical properties, and composite application
Global Diffusion in a Realistic Three-Dimensional Time-Dependent Nonturbulent Fluid Flow
We introduce and study the first model of an experimentally realizable
three-dimensional time-dependent nonturbulent fluid flow to display the
phenomenon of global diffusion of passive-scalar particles at arbitrarily small
values of the nonintegrable perturbation. This type of chaotic advection,
termed {\it resonance-induced diffusion\/}, is generic for a large class of
flows.Comment: 4 pages, uuencoded compressed postscript file, to appear in Phys.
Rev. Lett. Also available on the WWW from http://formentor.uib.es/~julyan/,
or on paper by reques
Marine stratocumulus aerosol-cloud relationships in the MASE-II experiment: Precipitation susceptibility in eastern Pacific marine stratocumulus
Observational data on aerosol-cloud-drizzle relationships in marine stratocumulus are presented from the second Marine Stratus/Stratocumulus Experiment (MASE-II) carried out in July 2007 over the eastern Pacific near Monterey, California. Observations, carried out in regions of essentially uniform meteorology with localized aerosol enhancements due to ship exhaust (“ship tracks”), demonstrate, in accord with those from numerous other field campaigns, that increased cloud drop number concentration Nc and decreased cloud top effective radius r_e are associated with increased subcloud aerosol concentration. Modulation of drizzle by variations in aerosol levels is
levels is clearly evident.
Variations of cloud base drizzle rate R_(cb) are found to be consistent with the proportionality,
R_(cb) / H^3/N_c, where H is cloud depth. Simultaneous aircraft and A-Train satellite
observations are used to quantify the precipitation susceptibility of clouds to aerosol
perturbations in the eastern Pacific region
Evaluation of Methicillin-Resistant Staphylococcus aureus Carriage and High Livestock Production Areas in North Carolina through Active Case Finding at a Tertiary Care Hospital
: Recent reports from the Netherlands document the emergence of novel multilocus sequence
typing (MLST) types (e.g., ST-398) of methicillin-resistant Staphylococcus aureus (MRSA) in livestock,
particularly swine. In Eastern North Carolina (NC), one of the densest pig farming areas in the United
States, as many as 14% of MRSA isolates from active case finding in our medical center have no
matches in a repetitive sequence-based polymerase chain reaction (rep-PCR) library. The current
study was designed to determine if these non-matched MRSA (NM-MRSA) were geographically
associated with exposure to pig farming in Eastern NC. While residential proximity to farm waste
lagoons lacked association with NM-MRSA in a logistic regression model, a spatial cluster was
identified in the county with highest pig density. Using MLST, we found a heterogeneous distribution
of strain types comprising the NM-MRSA isolates from the most pig dense regions, including ST-5
and ST-398. Our study raises the warning that patients in Eastern NC harbor livestock associated
MRSA strains are not easily identifiable by rep-PCR. Future MRSA studies in livestock dense areas in
the U.S. should investigate further the role of pig–human interactions
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