Left Ventricular Longitudinal Function Assessed by Speckle Tracking Ultrasound from a Single Apical Imaging Plane

Background. Transthoracic ultrasonography of the heart is valuable in monitoring and treatment of critically ill patients. Speckle tracking ultrasound (STU) has proven valid in estimating left ventricular systolic deformation. The aims of the study were to compare conventional and automated STU and to determine whether left ventricular systolic deformation could be estimated from one single imaging plane. Methods. 2D-echocardiography cine-loops were obtained from 20 patients for off-line speckle tracking analysis, consisting of manually tracing of the endocardial border (conventional method) or automatically drawn boundaries (automated method). Results. We found a bias of 0,6 (95% CI −2.2−3.3) for global peak systolic strain comparing the automated and the conventional method. Comparing global peak systolic strain of apical 4-chamber cine-loops with averaged Global Peak Strain obtained from apical 4, 2 and long axis cine-loops, showed a bias of 0.1 (95% CI −3.9−4.0). The agreement between subcostal 4-chamber and apical 4-chamber global peak systolic strain was 4.4 (95% CI −3.7−12.5). Conclusion. We found good agreement between the conventional and the automated method. STU applied to single apical 4-chamber cine-loops is in excellent agreement with overall averaged global peak systolic strain, while subcostal 4-chamber cine-loops proved less compliant with speckle tracking ultrasound

Synergistic platelet inhibition between Omega-3 and acetylsalicylic acid dose titration; an observational study

Background: Omega-3 and acetylsalicylic acid (ASA) are two widely used “over-the-counter” drugs. Previous researchhas shown multiple electrode aggregometry (MEA) can detect ASA and varying Omega-3 platelet inhibiting effects.Synergistic platelet inhibiting effects of ASA and Omega-3 have been found using other methods than MEA. The aimof this study was to investigate the antiplatelet effects of Omega-3, and ASA synergism with MEA.Methods: Ten healthy male volunteers ingested Omega-3 (1260mg/day) for 5 days. MEA was used to analyse plateletfunction before and after Omega-3 intake. Aggregation was initiated using three different agonists and measured asarea under the curve (AUC): adenosine diphosphate (ADP), thrombin receptor activating peptide (TRAP) andarachidonic acid (ASPI). Two concentrations of ASA were dose titrated ex vivo to 2 out of 3 ASPI test cells in order tomeasure synergism between Omega-3 and ASA.Results: Following 5 days Omega-3 intake, ADP, TRAP and ASPI AUC did not change significantly. In vitro ASA beforeOmega-3 intake, reduced ASPI AUC < 30 U, indicating a strong platelet inhibiting effect. Below this AUC level, the 5 daysOmega-3 intake increased ASPI-AUC with the ex vivo added low dose ASA (P = 0.02) and high dose ASA (P = 0.04).Conclusions: No synergism between ASA and Omega-3 was found using the MEA ASPI test. The surprising increase inASPI-AUC following Omega-3 intake and ex vivo ASA suggest that there are methodological issuses with the MEA ASPI test

Casimir effect between anti-de Sitter braneworlds

We calculate the one-loop effective action of a scalar field with general mass and coupling to the curvature in the detuned Randall-Sundrum brane world scenario, where the four-dimensional branes are anti-de Sitter. We make use of conformal transformations to map the problem to one on the direct product of the hyperbolic space H^4 and the interval. We also include the cocycle function for this transformation. This Casimir potential is shown to give a sizable correction to the classical radion potential for small values of brane separation.Comment: 14 pages, 3 figures, revtex. Typos corrected and references added. Minor mistakes in Eq. 48 and Eq. A10 correcte

Complementarity of Resonant and Nonresonant Strong WWWW Scattering at the LHC

We exhibit a complementary relationship between resonant $WZ$ and nonresonant $W^+W^+$ scattering in a chiral Lagrangian model of the electroweak symmetry breaking sector with a dominant ``$\rho$'' meson. We use the model to estimate the minimum luminosity for the LHC to ensure a ``no-lose'' capability to observe the symmetry breaking sector.Comment: 13 pages, LateX with uuencoded postcript figures (figures available by mail to the technologically challenged), LBL-3484

Brane World Susy Breaking from String/M Theory

String and M-theory realizations of brane world supersymmetry breaking scenarios are considered in which visible sector Standard Model fields are confined on a brane, with hidden sector supersymmetry breaking isolated on a distant brane. In calculable examples with an internal manifold of any volume the Kahler potential generically contains brane--brane non-derivative contact interactions coupling the visible and hidden sectors and is not of the no-scale sequestered form. This leads to non-universal scalar masses and without additional assumptions about flavor symmetries may in general induce dangerous sflavor violation even though the Standard Model and supersymmetry branes are physically separated. Deviations from the sequestered form are dictated by bulk supersymmetry and can in most cases be understood as arising from exchange of bulk supergravity fields between branes or warping of the internal geometry. Unacceptable visible sector tree-level tachyons arise in many models but may be avoided in certain classes of compactifications. Anomaly mediated and gaugino mediated contributions to scalar masses are sub-dominant except in special circumstances such as a flat or AdS pure five--dimensional bulk geometry without bulk vector multiplets.Comment: Latex, 83 pages, references adde

Phases of Chiral Gauge Theories

We discuss the behavior of two non-supersymmetric chiral SU(N) gauge theories, involving fermions in the symmetric and antisymmetric two-index tensor representations respectively. In addition to global anomaly matching, we employ a recently proposed inequality constraint on the number of effective low energy (massless) degrees of freedom of a theory, based on the thermodynamic free energy. Several possible zero temperature phases are consistent with the constraints. A simple picture for the phase structure emerges if these theories choose the phase, consistent with global anomaly matching, that minimizes the massless degree of freedom count defined through the free energy. This idea suggests that confinement with the preservation of the global symmetries through the formation of massless composite fermions is in general not preferred. While our discussion is restricted mainly to bilinear condensate formation, higher dimensional condensates are considered for one case. We conclude by commenting briefly on two related supersymmetric chiral theories.Comment: 23 pages, 2 figures, ReVTeX, improved forma