High spin states in147Tb

The level scheme of¹⁴⁷Tb has been extended to 116 levels and 198 transitions in two experiments with the OSIRIS Compton suppressed detector array at the HMI Berlin with the reactions¹²²Sn(³¹P, 6n)¹⁴⁷Tb at 160 MeV and¹²⁰Sn(³¹P, 4n)¹⁴⁷Tb at 152 MeV. Evidence for a new high spin isomer atE=7664.1 keV with a life-time of the order of 2 ns has been found.     

High spin states in145Gd

The data from two experiments with heavy ion induced reactions at the OSIRIS Compton suppressed Ge detector array has been analyzed to study high spin states in¹⁴⁵Gd. The level scheme of¹⁴⁵Gd has been extended up to an excitation energy of 12 MeV and an estimated spin of 25 ?. No evidence for high spin isomers was found.     

Photoplate data acquisition in mass spectrometry with the IBM-PC/AT

An existing photoplate evaluation system has to be replaced by modern equipment. Instead of the old minicomputer system VARIAN 620/L, an IBM-PC/AT personal computer has been installed. This system is equipped with an intelligent I/O adapter (Data Translation) for acquiring and storing the whole amount of transmittance values of a photoplate in real time. This is the difference to the old system which only stores all relevant data around a detected line, including the background values. It has been shown that, principally, there is a gain in sensitivity which can be used for high purity analysis work. There may be better founded detection limits on a distinctly lower level than with the previous system, but also a secure determination of background values in line-free areas. In addition, the new sysstem is more flexible to evaluate also laser-generated photoplates.     

Vibrational study of silicon oxidation: H2O on Si(100)

The vibrational spectrum of water dissociatively adsorbed on Si(100) surfaces is obtained with surface infrared absorption spectroscopy. Low frequency spectra (< 1450 cm⁻¹ are acquired using a buried CoSi₂ layer as an internal mirror to perform external reflection spectroscopy. On clean Si(100), water dissociates into H and OH surface species as evidenced by EELS results [1] in the literature which show a Si---H stretching vibration (2082 cm⁻¹), and SiO---H vibrations (O---H stretch at 3660 cm⁻¹ and the Si---O---H bend and Si---O stretch of the hydroxyl group centered around 820 cm⁻¹). In this paper, infrared (IR) measurements are presented which confirm and resolve the issue of a puzzling isotopic shift for the Si---O mode of the surface hydroxyl group, namely, that the Si---O stretch of the O---H surface species formed upon H₂O exposure occurs at 825 cm⁻¹, while the Si---O stretch of the ---OD surface species formed upon D₂O exposure shifts to 840 cm⁻¹, contrary to what is expected for simple reduced mass arguments. The higher resolution of IR measurements versus typical EELS measurements makes it possible to identify a new mode at 898 cm⁻¹, which is an important piece of evidence in understanding the anomalous frequency shift. By comparing the results of measurements for adsorption of H¹⁶₂O, H¹⁸₂O and D₂O with the results from recently performed first-principles calculations, it can be shown that a strong vibrational interaction between the Si---O stretching and Si---O---H bending functional group vibrations of the hydroxyl group accounts for the observed isotopic shifts.     

Myocardial effects of local shock wave therapy in a Langendorff model

Objective

Applying shock waves to the heart has been reported to stimulate the heart and alter cardiac function. We hypothesized that shock waves could be used to diagnose regional viability.

Method

We used a Langendorff model to investigate the acute effects of shock waves at different energy levels and times related to systole, cycle duration and myocardial function.

Results

We found only a small time window to use shock waves. Myocardial fibrillation or extrasystolic beats will occur if the shock wave is placed more than 15 ms before or 30 ms after the onset of systole. Increased contractility and augmented relaxation were observed after the second beat, and these effects decreased after prolonging the shock wave delay from 15 ms before to 30 ms after the onset of systole. An energy dependency could be found only after short delays (−15 ms). The involved processes might include post-extrasystolic potentiation and simultaneous pacing.

Conclusion

In summary, we found that low-energy shock waves can be a useful tool to stimulate the myocardium at a distance and influence function.     

Evidence for the production of thermal muon pairs with masses above 1 GeV/c 2 in 158 A GeV indium-indium collisions

The yield of muon pairs in the invariant mass region 1<M<2.5 GeV/c ² produced in heavy-ion collisions significantly exceeds the sum of the two expected contributions, Drell-Yan dimuons and muon pairs from the decays of D meson pairs. These sources properly account for the dimuons produced in proton-nucleus collisions. In this paper, we show that dimuons are also produced in excess in 158 A GeV In-In collisions. We furthermore observe, by tagging the dimuon vertices, that this excess is not due to enhanced D meson production, but made of prompt muon pairs, as expected from a source of thermal dimuons specific to high-energy nucleus-nucleus collisions. The yield of this excess increases significantly from peripheral to central collisions, both with respect to the Drell-Yan yield and to the number of nucleons participating in the collisions. Furthermore, the transverse mass distributions of the excess dimuons are well described by an exponential function, with inverse slope values around 190 MeV. The values are independent of mass and significantly lower than those found at masses below 1 GeV/c ², rising there up to 250 MeV due to radial flow. This suggests the emission source of thermal dimuons above 1 GeV/c ² to be of largely partonic origin, when radial flow has not yet built up.     

Model reduction for nonlinear biomechanical structural analysis

For surgery training and on-line support during surgeries a method is required which is able to reduce simulation time possibly even to realtime. This contribution compares the effectiveness of three model reduction methods, all of which are widely used for linear problems, in the context of nonlinear structural mechanics. Three reduction methods will be extended to nonlinear elasticity including large deformations. The performance of the extended concepts is investigated for a simplified model of a human inferior turbinate in the context of the functional endoscopic sinus surgery. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Book review

Communicated by Professor Zimmermann