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Das Metabolische Syndrom stellt eine Kombination verschiedener metabolischer Anomalien in einem Individuum dar. Starkes Übergewicht gilt als maßgebende Größe in der Genese des Syndroms, welches mit einem enormen Risiko für kardiovaskuläre Erkrankungen einhergeht. Um die stark steigende Prävalenz des Metabolischen Syndroms einzudämmen, sind dringend Konzepte für die Behandlung, vor allem jedoch für die Prävention von Übergewicht erforderlich. Einen wichtigen Beitrag leisten diesbezüglich Ballaststoffe in der Ernährung. Sie tragen auf unterschiedlichen Wegen zur Gewichtskontrolle bei und beeinflussen zudem verschiedene mit dem Metabolischen Syndrom assoziierte Blutparameter. Ebenso werden protektive Effekte von Polyphenolen, welche zur Gruppe der sekundären Pflanzenstoffe zählen, beschrieben. Diese wirken u. a. auf den Glukose- sowie den Insulinhaushalt und greifen darüber hinaus in die Regulation der Fettverbrennung sowie des Energieverbrauches ein. Die Kombination beider Substanzgruppen verspricht bedeutendes gesundheitsförderndes Potential; dieses wurde gegenwärtig jedoch kaum untersucht. Carobballaststoff ist ein polyphenolreicher und vorwiegend unlöslicher Extrakt der Frucht des Johannisbrotbaumes (Ceratonia siliqua L). Bislang publizierte Studien zur physiologischen Wirksamkeit dieses Ballaststoffpräparates weisen sowohl beim Tier als auch beim Menschen bemerkenswerte hypocholesterinämische Eigenschaften nach. Inwiefern sich der Verzehr des Carobballaststoffes ebenso auf die Entwicklung von Übergewicht sowie anderen Messgrößen des Metabolischen Syndroms auswirkt, ist allerdings nicht bekannt. Die Zielstellung der Promotionsarbeit bestand darin, die postprandialen Wirkungen des Carobballaststoffverzehrs mit Hilfe einer Humanstudie aufzuzeigen. In die randomisierten, einfach verblindeten Untersuchungen im cross-over-Design wurden 20 gesunde Erwachsene im Alter zwischen 22 und 62 Jahren eingeschlossen. Unter Verwendung variierender Begleitmahlzeiten wurden die postprandialen Effekte verschiedener Mengen des Carobballaststoffes untersucht. Hierbei standen die Veränderungen der Plasmakonzentrationen von Glukose, Triglyceriden (TG), totalem und acyliertem Ghrelin sowie der Serumkonzentrationen von Insulin und nicht-veresterten Fettsäuren (NEFA) im Mittelpunkt der Betrachtungen. Der Verzehr des Carobballaststoffes in Kombination mit 200 ml Wasser und 50 g Glukose erhöhte die postprandialen Glukose- und Insulinkonzentrationen gegenüber der Glukoselösung ohne Ballaststoffzusatz. In Kombination mit 400 ml einer Flüssigmahlzeit verzehrt, senkte Carobballaststoff die postprandialen TG-, NEFA- und Ghrelin- (acyliert) Antworten. Die Untersuchung des respiratorischen Quotienten nach Zusatz von Carobballaststoff zur Flüssigmahlzeit mittels indirekter Respirationskalorimetrie bekräftigte die bereits bekannten Effekte auf den Lipidmetabolismus und wies zudem eine Steigerung der Fettverwertung unter Verminderung der Glukoseoxidation nach. Wurde Carobballaststoff schließlich in Lebensmittel eingebracht, sanken nach dem Verzehr dieser Lebensmittel erneut die postprandialen Konzentrationen an TG und NEFA. Gleichzeitig erhöhten sich die Glukose-, Insulin- sowie Ghrelin- (acyliert) Antworten. Carobballaststoff löst in Abhängigkeit von der jeweils verzehrten Begleitmatrix unterschiedliche Effekte aus. Das Präparat weist beachtliche Wirkungen auf die Blutlipide sowie den Energieverbrauch auf, hat indes ungünstige Wirkungen auf die Blutglukose, sofern er in Kombination mit einer veränderten Nährstoffmatrix aufgenommen wird. Carobballaststoff besitzt starkes gesundheitsförderndes Potential; jedoch sind weitere Studien notwendig, um seine Wirkungen sowie deren Voraussetzungen besser zu verstehen. Ferner sollten Untersuchungen über einen längeren Zeitraum vorgenommen werden, um die langfristige Relevanz der gewonnenen Ergebnisse darzulegen. Danach stellt die Anreicherung spezieller Lebensmittel mit Carobballaststoff einen geeigneten Weg dar, um von den viel versprechenden protektiven Wirkungen des Präparates zu profitieren.
This work introduces novel internal and external memory algorithms for computing voxel skeletons of massive voxel objects with complex network-like architecture and for converting these voxel skeletons to piecewise linear geometry, that is triangle meshes and piecewise straight lines. The presented techniques help to tackle the challenge of visualizing and analyzing 3d images of increasing size and complexity, which are becoming more and more important in, for example, biological and medical research. Section 2.3.1 contributes to the theoretical foundations of thinning algorithms with a discussion of homotopic thinning in the grid cell model. The grid cell model explicitly represents a cell complex built of faces, edges, and vertices shared between voxels. A characterization of pairs of cells to be deleted is much simpler than characterizations of simple voxels were before. The grid cell model resolves topologically unclear voxel configurations at junctions and locked voxel configurations causing, for example, interior voxels in sets of non-simple voxels. A general conclusion is that the grid cell model is superior to indecomposable voxels for algorithms that need detailed control of topology. Section 2.3.2 introduces a noise-insensitive measure based on the geodesic distance along the boundary to compute two-dimensional skeletons. The measure is able to retain thin object structures if they are geometrically important while ignoring noise on the object's boundary. This combination of properties is not known of other measures. The measure is also used to guide erosion in a thinning process from the boundary towards lines centered within plate-like structures. Geodesic distance based quantities seem to be well suited to robustly identify one- and two-dimensional skeletons. Chapter 6 applies the method to visualization of bone micro-architecture. Chapter 3 describes a novel geometry generation scheme for representing voxel skeletons, which retracts voxel skeletons to piecewise linear geometry per dual cube. The generated triangle meshes and graphs provide a link to geometry processing and efficient rendering of voxel skeletons. The scheme creates non-closed surfaces with boundaries, which contain fewer triangles than a representation of voxel skeletons using closed surfaces like small cubes or iso-surfaces. A conclusion is that thinking specifically about voxel skeleton configurations instead of generic voxel configurations helps to deal with the topological implications. The geometry generation is one foundation of the applications presented in Chapter 6. Chapter 5 presents a novel external memory algorithm for distance ordered homotopic thinning. The presented method extends known algorithms for computing chamfer distance transformations and thinning to execute I/O-efficiently when input is larger than the available main memory. The applied block-wise decomposition schemes are quite simple. Yet it was necessary to carefully analyze effects of block boundaries to devise globally correct external memory variants of known algorithms. In general, doing so is superior to naive block-wise processing ignoring boundary effects. Chapter 6 applies the algorithms in a novel method based on confocal microscopy for quantitative study of micro-vascular networks in the field of microcirculation.
The statistical analysis of the variations of the dayly-mean frequency of the maximum ionospheric electron density foF2 is performed in connection with the occurrence of (more than 60) earthquakes with magnitudes M > 6.0, depths h < 80 km and distances from the vertical sounding station R < 1000 km. For the study, data of the Tokyo sounding station are used, which were registered every hour in the years 1957-1990. It is shown that, on the average, foF2 decreases before the earthquakes. One day before the shock the decrease amounts to about 5 %. The statistical reliability of this phenomenon is obtained to be better than 0.95. Further, the variations of the occurrence probability of the turbulization of the F-layer (F spread) are investigated for (more than 260) earthquakes with M > 5.5, h < 80 km, R < 1000 km. For the analysis, data of the Japanese station Akita from 1969-1990 are used, which were obtained every hour. It is found that before the earthquakes the occurrence probability of F spread decreases. In the week before the event, the decrease has values of more than 10 %. The statistical reliability of this phenomenon is also larger than 0.95. Examining the seismo-ionospheric effects, here periods of time with weak heliogeomagnetic disturbances are considered, the Wolf number is less than 100 and the index ∑ Kp is smaller than 30.
In the present work, phenomena in the ionosphere are studied, which are connected with earthquakes (16 events) having a depth of less than 50 km and a magnitude M larger than 4. Analysed are night-time Es-spread effects using data of the vertical sounding station Petropavlovsk- Kanchatsky (φ=53.0°, λ=158.7°) from May 2004 until August 2004 registered every 15 minutes. It is found that the maximum distance of the earthquake from the sounding station, where pre-seismic phenomena are yet observable, depends on the magnitude of the earthquake. Further it is shown that 1-2 days before the earthquakes, in the premidnight hours, the appearance of Es-spread increases. The reliability of this increase amounts to 0.95.
A model of the generation of pulses of local electric fields with characteristic time scales of 1–10 minutes is considered for atmospheric conditions above fracture regions of earthquakes. In the model, it is proposed that aerosols, increased ionization velocity and upstreaming air flows occur at night-time conditions. The pulses of local electric fields cause respective pulses of infrared emissions. But infrared emissions with time scales of 1–10 minutes were not observed up to now experimentally. The authors think, that the considered non-stationary field and radiation effects might be a new-type of applicable earthquake indicators and ask to perform special earth-based and satellite observations of the night-time atmosphere in seismoactive fracture regions.
We numerically investigate nonlinear asymmetric square patterns in a horizontal convection layer with up-down reflection symmetry. As a novel feature we find the patterns to appear via the skewed varicose instability of rolls. The time-independent nonlinear state is generated by two unstable checkerboard (symmetric square) patterns and their nonlinear interaction. As the bouyancy forces increase, the interacting modes give rise to bifurcations leading to a periodic alternation between a nonequilateral hexagonal pattern and the square pattern or to different kinds of standing oscillations.
In this paper an analysis of the excitation conditions of mirror waves is done, which propagate parallel to an external magnetic field. There are found analytical expressions for the dispersion relations of the waves in case of different plasma conditions. These relations may be used in future to develop the nonlinear theory of mirror waves. In comparison with former analytical works, in the study the inuence of the magnetic field and nite temperatures of the ions parallel to the magnetic field are taken into account. Application is done for the earth's magnetosheath.
Basing on recent solar models, the excitation of ion-acoustic turbulence in the weaklycollisional, fully and partially-ionized regions of the solar atmosphere is investigated. Within the frame of hydrodynamics, conditions are found under which the heating of the plasma by ion-acoustic type waves is more effective than the Joule heating. Taking into account wave and Joule heating effects, a nonlinear differential equation is derived, which describes the evolution of nonlinear ion-acoustic waves in the collisional plasma.
A numerical MHD model is developed to investigate acceleration and heating of both thermal and auroral plasma. This is done for magnetospheric flux tubes in which intensive field aligned currents flow. To give each of these tubes, the empirical Tsyganenko model of the magnetospheric field is used. The parameters of the background plasma outside the flux tube as well as the strength of the electric field of magnetospheric convection are given. Performing the numerical calculations, the distributions of the plasma densities, velocities, temperatures, parallel electric field and current, and of the coefficients of thermal conductivity are obtained in a self-consistent way. It is found that EIC turbulence develops effectively in the thermal plasma. The parallel electric field develops under the action of the anomalous resistivity. This electric field accelerates both the thermal and the auroral plasma. The thermal turbulent plasma is also subjected to an intensive heating. The increase of the plasma of the Earth's ionosphere. Besides, studying the growth and dispersion properties of oblique ion cyclotron waves excited in a drifting magnetized plasma, it is shown that under non-stationary conditions such waves may reveal the properties of bursts of polarized transverse electromagnetic waves at frequencies near the patron gyrofrequency.
This paper deals with the Mie scattering kernels for multi-spectral data. The kernels may be represented in form of power series. Furthermore, the singular-value spectrum and the degree of ill-posedness in dependence on the refractive index of the particles are numerically approximated. A special hybrid regularization technique allows us to determine via inversion the particle distributions of different types.