317 research outputs found
Association of PET-measured myocardial flow reserve with echocardiography-estimated pulmonary artery systolic pressure in patients with hypertrophic cardiomyopathy
BackgroundPulmonary hypertension (PH) is a known complication of HCM and is a strong predictor of mortality. We aim to investigate the relationship between microvascular dysfunction measured by quantitative PET and PH in HCM patients.MethodsEighty-nine symptomatic HCM patients were included in the study. Each patient underwent two 20-min 13N-NH3 dynamic PET scans for rest and stress conditions, respectively. A 2-tissue irreversible compartmental model was used to fit the segments time activity curves for estimating segmental and global myocardial blood flow (MBF) and myocardial flow reserve (MFR). Echocardiographic derived PASP was utilized to estimate PH.ResultsPatients were categorized into two groups across PASP: PH (PASP > 36 mmHg) and no-PH (PASP ≤ 36 mmHg). patients with PH had larger left atrium, ratio of higher inflow early diastole (E) and atrial contraction (A) waves, E/A, and ratio of inflow and peak early diastolic waves, E/e', significantly reduced global stress MBF (1.85 ± 0.52 vs. 2.13 ± 0.56 ml/min/g; p = 0.024) and MFR (2.21 ± 0.57 vs. 2.62 ± 0.75; p = 0.005), while the MBFs at rest between the two groups were similar. There were significant negative correlations between global stress MBF/MFR and PASP (stress MBF: r = -0.23, p = 0.03; MFR: r = -0.32, p = 0.002); for regional MBF and MFR measurements, the highest linear correlation coefficients were observed in the septal wall (stress MBF: r = -0.27, p = 0.01; MFR: r = -0.31, p = 0.003). Global MFR was identified to be independent predictor for PH in multivariate regression analysis.ConclusionEchocardiography-derived PASP is negatively correlated with global MFR measured by 13N-NH3 dynamic PET. Global MFR is suggested to be an index of PH in HCM patients.</div
Shear Stress Measurements of Non-Spherical Particles in High Shear Rate Flows
The behavior of liquid-solid flows varies greatly depending on fluid viscosity; particle and liquid inertia; and collisions and near-collisions between particles. Shear stress measurements were made in a coaxial rheometer with a height to gap ratio (b/r0) of 11.7 and gap to outer radius ratio (h/b) of 0.166 that was specially designed to minimize the effects of secondary flows. Experiments were performed for a range of Reynolds numbers, solid fractions and ratio of particle to fluid densities. With neutrally buoyant particles, the dimensional shear stress exhibits a linear dependence on Reynolds number: the slope is monotonic but a non-linear function of the solid fraction. Though non-neutrally buoyant particles exhibit a similar linear dependence at higher Reynolds numbers, at lower values the shear stress exhibits a non-linear behavior in which the stress increases with decreasing Reynolds number due to particle settling
Effective Action and Schwinger Pair Production in Scalar QED
Some astrophysical objects are supposed to have very strong electromagnetic
fields above the critical strength. Quantum fluctuations due to strong
electromagnetic fields modify the Maxwell theory and particularly electric
fields make the vacuum unstable against pair production of charged particles.
We study the strong field effect such as the effective action and the Schwinger
pair production in scalar QED.Comment: RevTex 6 pages, no figure; Proceedings of APCTP Winter School on
Black Hole Astrophysics 2008, Jan 24-29, 200
Distinct Differentiation Programs Triggered by IL-6 And LPS in Teleost IgM+ B Cells in the Absence of Germinal Centers
We would like to thank Lucia Gonzalez and Maria Sanz for technical assistance. Professor Øystein Evensen is also acknowledged for providing us with the inactivated IPNV. This work was supported by the European Research Council (ERC Starting Grant 2011 280469) and by the European Commission under the 7th Framework Programme for Research and Technological Development (FP7) of the European Union (Grant Agreement 311993 TARGETFISH). T. W. received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference HR09011).Peer reviewedPublisher PD
Highly Efficient Autologous HIV-1 Isolation by Coculturing Macrophage With Enriched CD4+ T Cells From HIV-1 Patients
We described a novel HIV autologous isolation method based in coculturing macrophages and CD4+T-cell-enriched fractions from peripheral blood collected from antiretroviral-treated (ART) HIV patients. This method allows the isolation of high viral titers of autologous viruses, over 1010HIV RNA copies/ml, and reduces the time required to produce necessary amounts for virus for use as antigens presented by monocyte-derived myeloid cells in HIV therapeutic vaccine approaches. By applying these high titer and autologous virus produced in the patient-derived cells, we intended to elicit a boost of the immunological system response in HIV therapeutic vaccines in clinical trials.This study was partially supported by grants from the Spanish Ministry of Economy (MINECO) (grants: SAF2015-66193-R, SAF-2017-88089-R, RTI2018-096309-B-I00); the Fondo Europeo para el Desarrollo Regional (FEDER); the SPANISH AIDS Research Network RD16/0025/0002 and RD16/0025/0014-ISCIII-FEDER (RIS); the Fondo de Investigación Sanitaria (FIS) PI12/01247 and PI20/00676; and HIVACAT program and the CERCA Programme/Generalitat de Catalunya SGR 615 and SGR 653. The project leading to these results has received funding from “la Caixa” Foundation under agreement. This study was also supported in part with federal funds from the National Cancer Institute, National Institutes of Health, under contract Nos. HHSN261200800001E and 75N91019D00024.S
Theory of Thermodynamic Stresses in Colloidal Dispersions at the Glass Transition
We discuss the nonlinear rheology of dense colloidal dispersions at the glass
transition. A first principles approach starting with interacting Brownian
particles in given arbitrary homogeneous (incompressible) flow neglecting
hydrodynamic interactions is sketched. It e.g. explains steady state flow
curves for finite shear rates measured in dense suspensions of thermosensitive
core-shell particles consisting of a polystyrene core and a crosslinked
poly(N-isopropylacrylamide)(PNIPAM) shell. The exponents of simple and
generalized Herschel Bulkley laws are computed for hard spheres.Comment: 3 pages, 1 figure; contribution to The XVth International Congress on
Rheology, August 3-8, 2008, Monterey, California; submitted to J. Rheo
Automated lesion detection of breast cancer in [18F] FDG PET/CT using a novel AI-Based workflow
UNLABELLED: Applications based on artificial intelligence (AI) and deep learning (DL) are rapidly being developed to assist in the detection and characterization of lesions on medical images. In this study, we developed and examined an image-processing workflow that incorporates both traditional image processing with AI technology and utilizes a standards-based approach for disease identification and quantitation to segment and classify tissue within a whole-body [
METHODS: One hundred thirty baseline PET/CT studies from two multi-institutional preoperative clinical trials in early-stage breast cancer were semi-automatically segmented using techniques based on PERCIST v1.0 thresholds and the individual segmentations classified as to tissue type by an experienced nuclear medicine physician. These classifications were then used to train a convolutional neural network (CNN) to automatically accomplish the same tasks.
RESULTS: Our CNN-based workflow demonstrated Sensitivity at detecting disease (either primary lesion or lymphadenopathy) of 0.96 (95% CI [0.9, 1.0], 99% CI [0.87,1.00]), Specificity of 1.00 (95% CI [1.0,1.0], 99% CI [1.0,1.0]), DICE score of 0.94 (95% CI [0.89, 0.99], 99% CI [0.86, 1.00]), and Jaccard score of 0.89 (95% CI [0.80, 0.98], 99% CI [0.74, 1.00]).
CONCLUSION: This pilot work has demonstrated the ability of AI-based workflow using DL-CNNs to specifically identify breast cancer tissue as determined by
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