Hamiltonian dynamics and constrained variational calculus: continuous and discrete settings

The aim of this paper is to study the relationship between Hamiltonian dynamics and constrained variational calculus. We describe both using the notion of Lagrangian submanifolds of convenient symplectic manifolds and using the so-called Tulczyjew's triples. The results are also extended to the case of discrete dynamics and nonholonomic mechanics. Interesting applications to geometrical integration of Hamiltonian systems are obtained.Comment: 33 page

Quaternion Solution for the Rock'n'roller: Box Orbits, Loop Orbits and Recession

We consider two types of trajectories found in a wide range of mechanical systems, viz. box orbits and loop orbits. We elucidate the dynamics of these orbits in the simple context of a perturbed harmonic oscillator in two dimensions. We then examine the small-amplitude motion of a rigid body, the rock'n'roller, a sphere with eccentric distribution of mass. The equations of motion are expressed in quaternionic form and a complete analytical solution is obtained. Both types of orbit, boxes and loops, are found, the particular form depending on the initial conditions. We interpret the motion in terms of epi-elliptic orbits. The phenomenon of recession, or reversal of precession, is associated with box orbits. The small-amplitude solutions for the symmetric case, or Routh sphere, are expressed explicitly in terms of epicycles; there is no recession in this case

The Possible "Proton Sponge " Effect of Polyethylenimine (PEI) Does Not Include Change in Lysosomal pH.

Polycations such as polyethylenimine (PEI) are used in many novel nonviral vector designs and there are continuous efforts to increase our mechanistic understanding of their interactions with cells. Even so, the mechanism of polyplex escape from the endosomal/lysosomal pathway after internalization is still elusive. The “proton sponge ” hypothesis remains the most generally accepted mechanism, although it is heavily debated. This hypothesis is associated with the large buffering capacity of PEI and other polycations, which has been interpreted to cause an increase in lysosomal pH even though no conclusive proof has been provided. In the present study, we have used a nanoparticle pH sensor that was developed for pH measurements in the endosomal/lysosomal pathway. We have carried out quantitative measurements of lysosomal pH as a function of PEI content and correlate the results to the “proton sponge ” hypothesis. Our measurements show that PEI does not induce change in lysosomal pH as previously suggested and quantification of PEI concentrations in lysosomes makes it uncertain that the “proton sponge ” effect is the dominant mechanism of polyplex escape

Beeinflussung der Vorderkantenablösung durch akustische Anregung

Der Einfluß akustischer Anregung auf die Grenzschichtablösung von einem Flügel endlicher Spannweite wurde mittels Strömungssichtbarmachung untersucht. Ein Flügelmodell mit einer Streckung Spannweite: Flügeltiefe = 3 wurde im Bereich 0 < Ma < 0,1 und 6 x 10 hoch 5 < Re < 1.2 x 10 hoch 6 bei Anstellwinkeln bis zu 25 und Schiebewinkeln bis zu 30 getestet. Die Wirkungen sphärischer Schallwellen von einer Punktschallquelle im Fernfeld sowie der durch einen Hohlspiegel gebündelten Bestrahlung einer Teilfläche des Flügels wurden untersucht. Die Versuchsergebnisse zeigen, daß durch Schallanregung mit geeigneter Frequenz die bei hohen Anstellwinkeln auftretende Strömungsablösung an der Flügelvorderkante zu einer turbulenten Ablösung nahe der Flügelmitte umgewandelt und damit das abgelöste Gebiet stark verkleinert wird

Detection and Discrimination of X-Ray Radiation Sources

International Telemetering Conference Proceedings / October 14-16, 1975 / Sheraton Inn, Silver Spring, MarylandWhile studying radiation sources in X-ray range by devices, carried to the near-Earth orbit, there appeares some problems, called by the necessity of uninterrupted scanning of the sky sphere and high speed of canals' test, which leads, consequently, to a considerable volume of data. Side by side with strong sources of radiation one shows great interest to the weak ones which may turn out to be unknown to the science stars. On detecting the source, it is necessary to get a number of parameters, characterizing its structure. Devices of the space station "Saljut 4", carried an enormous deposit into the study of sources in X-ray range. The analyses of results shows, that beside useful signal from X-ray telescopes, a considerable number of superfluous references enters the radioline. Highly effective algorythm of detection and discrimination of useful signals, allowing to raise the informational capability of radioline is represented in the work. Superfluous references, which are stipulated by a galactic background are excluded from the whole data stream. The use of this kind of algorythm allows to discriminate more legible the sources of radiation in on-board and on-Earth use. The effectiveness of this algorythm is shown in adaptation of experimental data, got from X-ray telescopes of the space station "Saljut-4".International Foundation for TelemeteringProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection

Relationship of anemia with clinicolaboratory measures of inflammation activity in patients with rheumatoid arthritis

Objective. To study relationship of anemic syndrome with inflammation activity measures in pts with rheumatoid arthritis (RA). Material and methods. 177 pts with RA fulfilled 1987 ACR criteria were included. 132 from them had anemia at the examination. Results were processed with complex of descriptive, structural and multivariate statistics. Results. Close relationship of RA clinical features with erythropoiesis disturbances clinically manifesting with anemia development was proved. Critical hemoglobin level (<113 g/1) was determined at which pathological processes in erythron leading to the development of anemia begin significantly influence severity of immunopathological rheumatoid process. Diapasons of disease activity measures were revealed associated with anemia presence or absence in pts with RA. Diagnostic value of studied measures diapasons for prognosis of anemia development in RA was determined. Conclusion. The results of the study allow developing criteria for prognosis of anemia appearance in RA pts with normal blood concentration of hemoglobin. Such method could help to reveal early disturbances of erythron and improve RA treatment schemes with erythropoiesis modulating drugs

HYBRID REVASCULIZATION AS METHOD OF SURGICAL TREATMENT OF ISCHEMIC CORONARY DISEASE IN NUMEROUS LESIONS OF CORONARY BED

Hybrid revasculization of myocardium combined the advantages of mammary-coronary bypass surgery and coronary arteries stenting. It presented itself as a perspective direction in treatment of ischemic coronary disease. The article provides the results of comparison of usage of hybrid revasculization of myocardium and aortocoronary bypass in 71 patients with multivessel coronary artery disease. The data obtained indicated, that hybrid approach allowed complete revasculization of the myocardium (as in case of aortocoronary bypass), fast recovery of the patient, shortening a hospital stay due to decrease of intra- and postoperative complications