559 research outputs found
Left ventricular to left atrial communication secondary to a paraaortic abscess: Color flow doppler documentation
Aortic root abscess occurs frequently in aortic prosthetic valve infective endocarditis. The present echocardiography report documents a ruptured abscess that led to a direct communication between the left ventricular outflow tract and the left atrium confirmed by real-time (color flow) Doppler imaging
Semiclassical Corrections to a Static Bose-Einstein Condensate at Zero Temperature
In the mean-field approximation, a trapped Bose-Einstein condensate at zero
temperature is described by the Gross-Pitaevskii equation for the condensate,
or equivalently, by the hydrodynamic equations for the number density and the
current density. These equations receive corrections from quantum field
fluctuations around the mean field. We calculate the semiclassical corrections
to these equations for a general time-independent state of the condensate,
extending previous work to include vortex states as well as the ground state.
In the Thomas-Fermi limit, the semiclassical corrections can be taken into
account by adding a local correction term to the Gross-Pitaevskii equation. At
second order in the Thomas-Fermi expansion, the semiclassical corrections can
be taken into account by adding local correction terms to the hydrodynamic
equations
Design Implementation and Evaluation of a Mobile Continuous Blood Oxygen Saturation Monitoring System
Objective: In this study, we built a mobile continuous Blood Oxygen Saturation (SpO2) monitor, and for the first time, explored key design principles towards daily applications. Methods: We firstly built a customized wearable computer that can sense two-channel photoplethysmogram (PPG) signals, and transmit the signals wirelessly to smartphone. Afterwards, we explored many SpO2 model building principles, focusing on linear/nonlinear models, different PPG parameter calculation methods, and different finger types. Moreover, we further compared PPG sensor placement principles by comparing different hand configurations and different finger configurations. Finally, a dataset collected from eleven human subjects was used to evaluate the mobile health monitor and explore all of the above design principles.
Results: The experimental results show that the root mean square error of the SpO2 estimation is only 1.8, indicating the effectiveness of the system.
Conclusion: These results indicate the effectiveness of the customized mobile SpO2 monitor and the selected design principles.
Significance: This research is expected to facilitate the continuous SpO2 monitoring of patients with clinical indications
Fluorescence decay in aperiodic Frenkel lattices
We study motion and capture of excitons in self-similar linear systems in
which interstitial traps are arranged according to an aperiodic sequence,
focusing our attention on Fibonacci and Thue-Morse systems as canonical
examples. The decay of the fluorescence intensity following a broadband pulse
excitation is evaluated by solving the microscopic equations of motion of the
Frenkel exciton problem. We find that the average decay is exponential and
depends only on the concentration of traps and the trapping rate. In addition,
we observe small-amplitude oscillations coming from the coupling between the
low-lying mode and a few high-lying modes through the topology of the lattice.
These oscillations are characteristic of each particular arrangement of traps
and they are directly related to the Fourier transform of the underlying
lattice. Our predictions can be then used to determine experimentally the
ordering of traps.Comment: REVTeX 3.0 + 3PostScript Figures + epsf.sty (uuencoded). To appear in
Physical Review
Attenuation of Host NO Production by MAMPs Potentiates Development of the Host in the Squid-Vibrio Symbiosis
The presence of bacterial pathogens typically upregulates the host’s production of nitric oxide synthase (NOS) and nitric oxide (NO) as antimicrobial agents. This dramatic response is often mediated by microbe-associated molecular patterns (MAMPs) of the pathogen. In contrast, previous studies of the beneficial Euprymna scolopes/Vibrio fischeri symbiosis demonstrated that symbiont colonization results in an attenuation of host NOS/NO, which occur in high levels in the hatchling light organ. In the present study, we sought to determine whether V. fischeri MAMPs, specifically lipopolysaccharide (LPS) and the peptidoglycan derivative tracheal cytotoxin (TCT), attenuate NOS/NO, and whether this activity mediates the MAMPs-induced light organ morphogenesis. Using confocal microscopy, we visualized and quantified the levels of NOS with immunocytochemistry and NO with a NO-specfic fluorochrome. When added exogenously to seawater containing hatchling animals, V. fischeri LPS and TCT together, but not individually, induced normal NOS/NO attenuation. Further, V. fischeri mutants defective in TCT release did not. Experiments with NOS inhibitors and NO donors provided evidence that NO mediates the apoptosis and morphogenesis associated with symbiont colonization. Attenuation of NOS/NO by LPS and TCT in the squid-vibrio symbiosis provides another example of how the host’s response to MAMPs depends on the context (i.e., beneficial or pathogenic bacteria). These data also provide a mechanism by which symbiont MAMPs regulate host development through NO attenuation
Stokesian jellyfish: Viscous locomotion of bilayer vesicles
Motivated by recent advances in vesicle engineering, we consider
theoretically the locomotion of shape-changing bilayer vesicles at low Reynolds
number. By modulating their volume and membrane composition, the vesicles can
be made to change shape quasi-statically in thermal equilibrium. When the
control parameters are tuned appropriately to yield periodic shape changes
which are not time-reversible, the result is a net swimming motion over one
cycle of shape deformation. For two classical vesicle models (spontaneous
curvature and bilayer coupling), we determine numerically the sequence of
vesicle shapes through an enthalpy minimization, as well as the fluid-body
interactions by solving a boundary integral formulation of the Stokes
equations. For both models, net locomotion can be obtained either by
continuously modulating fore-aft asymmetric vesicle shapes, or by crossing a
continuous shape-transition region and alternating between fore-aft asymmetric
and fore-aft symmetric shapes. The obtained hydrodynamic efficiencies are
similar to that of other low Reynolds number biological swimmers, and suggest
that shape-changing vesicles might provide an alternative to flagella-based
synthetic microswimmers
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