607 research outputs found
Kombinierte dorsale und palmare Plattenosteosynthese bei distalen intraartikulÀren Radiusfrakturen
Zusammenfassung: Hintergrund: Behandlungsziel bei komplexen distalen intraartikulĂ€ren Radiusfrakturen ist die anatomische Gelenkrekonstruktion. In seltenen FĂ€llen kann dies nur mit einer kombinierten, dorsalen und palmaren AbstĂŒtzung erreicht werden, trotz der zunehmenden Erfahrung mit winkelstabilen palmaren Implantaten. Diese retrospektive QualitĂ€tskontrollstudie untersucht das funktionelle, radiologische und subjektive Outcome der mit dieser Technik operierten Patienten. Patienten und Methoden : An der Klinik fĂŒr Unfallchirurgie des UniversitĂ€tsspital ZĂŒrich wurden zwischen MĂ€rz 1999 und Januar 2003 von 360 Patienten mit instabiler distaler Radiusfraktur 30 Patienten mit komplexer C2-/C3-Fraktur ĂŒber einen kombinierten dorsopalmaren Zugang mit einer 3,5-mm-T-Platte und dorsal mit zwei 1/4-Rohr-Platten behandelt und in die Studie eingeschlossen (9 Frauen, 21MĂ€nner, Mittelwert des Alters 52). Nachkontrolliert werden konnten 25 der 30 Patienten im Mittel 29 Monate nach Unfall. Ergebnisse: Die angestrebte anatomische Rekonstruktion gelang nicht bei allen Patienten: 56% zeigten leichte, 28% schwere Zeichen der Arthrose. Die Flexion erreichte 66%, die Extension 75% der gesunden Seite, Pronation und Supination sogar 98 bzw. 91%. Die Kraft beim Faustschluss betrug 75% der kontralateralen Seite. Zehn Patienten (40%) entwickelten im Verlauf ein komplexes regionales Schmerzsyndrom (CRPS). Die RĂŒckkehr zur Arbeit war nach 120 Tagen möglich. Schlussfolgerung: Die dorsopalmare Plattenosteosynthese komplexer, distaler intraartikulĂ€rer Radiusfrakturen erlaubt eine Gelenkrekonstruktion mit gutem subjektivem, funktionellem und radiologischem Resultat, dies trotz des durch den beidseitigen Zugang verursachten zusĂ€tzlichen Weichteilschaden. Das hohe CRPS-Risiko, aber auch der lange Arbeitsausfall mĂŒssen bei der PatientenaufklĂ€rung berĂŒcksichtigt werde
a comparison of morphological and petrological methods
In planetary sciences, the emplacement of lava flows is commonly modelled
using a single rheological parameter (apparent viscosity or apparent yield
strength) calculated from morphological dimensions using Jeffreysʌ and Hulmeʌs
equations. The rheological parameter is then typically further interpreted in
terms of the nature and chemical composition of the lava (e.g., mafic or
felsic). Without the possibility of direct sampling of the erupted material,
the validity of this approach has remained largely untested. In modern
volcanology, the complex rheological behaviour of lavas is measured and
modelled as a function of chemical composition of the liquid phase, fractions
of crystals and bubbles, temperature and strain rate. Here, we test the
planetary approach using a terrestrial basaltic lava flow from the Western
Volcanic Zone in Iceland. The geometric parameters required to employ
Jeffreysʌ and Hulmeʌs equations are accurately estimated from high-resolution
HRSC-AX Digital Elevation Models. Samples collected along the lava flow are
used to constrain a detailed model of the transient rheology as a function of
cooling, crystallisation, and compositional evolution of the residual melt
during emplacement. We observe that the viscosity derived from the morphology
corresponds to the value estimated when significant crystallisation inhibits
viscous deformation, causing the flow to halt. As a consequence, the inferred
viscosity is highly dependent on the details of the crystallisation sequence
and crystal shapes, and as such, is neither uniquely nor simply related to the
bulk chemical composition of the erupted material. This conclusion, drawn for
a mafic lava flow where crystallisation is the primary process responsible for
the increase of the viscosity during emplacement, should apply to most of
martian, lunar, or mercurian volcanic landforms, which are dominated by
basaltic compositions. However, it may not apply to felsic lavas where
vitrification resulting from degassing and cooling may ultimately cause lava
flows to halt
Brain oscillatory activity as a biomarker of motor recovery in chronic stroke
In the present work, we investigated the relationship of oscillatory sensorimotor brain activity to motor recovery. The neurophysiological data of 30 chronic stroke patients with severe upperâlimb paralysis are the basis of the observational study presented here. These patients underwent an intervention including movement training based on combined brainâmachine interfaces and physiotherapy of several weeks recorded in a doubleâblinded randomized clinical trial. We analyzed the alpha oscillations over the motor cortex of 22 of these patients employing multilevel linear predictive modeling. We identified a significant correlation between the evolution of the alpha desynchronization during rehabilitative intervention and clinical improvement. Moreover, we observed that the initial alpha desynchronization conditions its modulation during intervention: Patients showing a strong alpha desynchronization at the beginning of the training improved if they increased their alpha desynchronization. Patients showing a small alpha desynchronization at initial training stages improved if they decreased it further on both hemispheres. In all patients, a progressive shift of desynchronization toward the ipsilesional hemisphere correlates significantly with clinical improvement regardless of lesion location. The results indicate that initial alpha desynchronization might be key for stratification of patients undergoing BMI interventions and that its interhemispheric balance plays an important role in motor recovery.Bundesministerium fĂŒr Bildung und Forschung, Grant/Award Numbers: 13GW0053, 16SV7754; Deutsche Forschungsgemeinschaft; Deutscher Akademischer Austauschdienst, Grant/Award Number: 9156335
Interaction imaging with amplitude-dependence force spectroscopy
Knowledge of surface forces is the key to understanding a large number of
processes in fields ranging from physics to material science and biology. The
most common method to study surfaces is dynamic atomic force microscopy (AFM).
Dynamic AFM has been enormously successful in imaging surface topography, even
to atomic resolution, but the force between the AFM tip and the surface remains
unknown during imaging. Here, we present a new approach that combines high
accuracy force measurements and high resolution scanning. The method, called
amplitude-dependence force spectroscopy (ADFS) is based on the
amplitude-dependence of the cantilever's response near resonance and allows for
separate determination of both conservative and dissipative tip-surface
interactions. We use ADFS to quantitatively study and map the nano-mechanical
interaction between the AFM tip and heterogeneous polymer surfaces. ADFS is
compatible with commercial atomic force microscopes and we anticipate its
wide-spread use in taking AFM toward quantitative microscopy
Sustainable Management of Water Resources
The Dawn spacecraft arrived at dwarf planet Ceres in spring 2015 and imaged its surface from four successively lower polar orbits at ground sampling dimensions between âŒ1.3âŻkm/px and âŒ35âŻm/px. To understand the geological history of Ceres a mapping campaign was initiated to produce a set of 15 quadrangle-based geological maps using the highest-resolution Framing Camera imagery. Here we present the geological map of the Ac-10 Rongo Quadrangle, which is located at the equator encompassing the region from 22°N to 22°S and 288° to 360°E. The total relief within the quadrangle is 11.1âŻkm with altitudes ranging from about â7.3âŻkm to +3.8âŻkm. We identified nine geological units based on surface morphology and surface textural characteristics. The dominant and most widespread unit is the cratered terrain (crt) representing ancient reworked crustal material. Its consistent formation age across the quadrangle is 1.8âŻGa. Two edifices (unit th), Ahuna Mons and an unnamed tholus within Begbalel Crater, are interpreted to be of (cryo)volcanic origin. The southwest portion of the quadrangle is dominated by ejecta material (Ye) emplaced during the formation of the 260-km diameter Yalode impact basin at about 580 Ma. Rayed crater ejecta material (cr) is dominant in the eastern part of the quadrangle but also occurs in isolated patches up to a distance of 455âŻkm from the 34âŻkm diameter source crater Haulani. The remaining five geological units also represent impact crater materials: degraded rim (crdeg), bright crater (cb), hummocky floor (cfh), talus (ta), and crater (c) materials. Widespread Yalode and Haulani ejecta materials can potentially be utilised as stratigraphic markers. Therefore, it is essential to consistently map their full areal extent and to date their formations using impact crater statistics
Latest Developments from the S-DALINAC*
The S-DALINAC is a 130 MeV superconducting recirculating electron accelerator serving several nuclear and radiation physics experiments as well as driving an infrared free-electron laser. A system of normal conducting rf resonators for noninvasive beam position and current measurement was established. For the measurement of gamma-radiation inside the accelerator cave a system of Compton diodes has been developed and tested. Detailed investigations of the transverse phasespace were carried out with a tomographical reconstruction method of optical transition radiation spots. The method can be applied also to non-Gaussian phasespace distributions. The results are in good accordance with simulations. To improve the quality factor of the superconducting 3 GHz cavities, an external 2K testcryostat was commissioned. The influence of electro-chemical polishing and magnetic shielding is currently under investigation. A digital rf-feedback-system for the accelerator cavities is being developed in order to improve the energy spread of the beam of the S-DALINAC. * Supported by the BMBF under contract no. 06 DA 820, the DFG under contract no. Ri 242/12-1 and -2 and the DFG Graduiertenkolleg 'Physik und Technik von Beschleunigern
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