CT myelography for diagnosis of brachial plexus avulsion in small animals

Avulsion of nerve roots of the brachial plexus can be diagnosed clinically, neurologically, radiographically and by electromyography. But like the myelography these techniques are inprecise for determination of the severity (partial or complete disruption) and the localization of the lesion. In human medicine the combination of computerized tomography with myelography shows high accuracy. Veterinary reports of experience in this field are not yet known. The aim of the present study was to demonstrate nerve root avulsions using myelography and computerized tomography. Three dogs and one cat with traumatic lesions of the brachial plexus were examined. The lesion could be seen in all patients. Thus CT-myelography results in an improved prognostic assessment of brachial plexus paralysis. Moreover, this technique could become one of the most important diagnostic methods for brachial plexus lesions involving nerve root reinsertion--neurotizations in veterinary medicine

Scanning Near-Field Optical Microscopy (SNOM) and its Application in Mineralogy

Gutmannsbauer W, Huser T, Lacoste T, Heinzelmann H, Güntherodt HJ. Scanning Near-Field Optical Microscopy (SNOM) and its Application in Mineralogy. SCHWEIZERISCHE MINERALOGISCHE UND PETROGRAPHISCHE MITTEILUNGEN. 1995;75(2):259-264.Scanning near-field optical microscopy (SNOM) is a member of the family of scanning probe microscopes. It combines the high three dimensional resolution of a scanning force microscope with the contrast mechanisms of an optical microscope. An optical resolution beyond the diffraction limit can be achieved. We show the first application of this technique in the field of mineralogy, and we point out its future potential

Das intrakranielle Meningeom: Befunde, Therapie und Ergebnisse bei neun Katzen und einem Hund

Nine cats and one dog with intracranial meningioma, which underwent surgery at the Department of Veterinary Surgery, University of Munich, Germany were evaluated retrospectively. One cat died shortly after surgery whereas the remaining 9 animals survived between 8 to 43 months (mean, 21.9 months) after surgery. Relapse was seen in 2 cats shortly after surgery and these animals were re-operated. After surgery, computed tomography was performed to ascertain that the tumour was completely removed. Pre-operative symptoms disappeared rapidly after surgery, except central blindness which persisted. Initial clinical observations and results of in vitro studies using feline meningioma cells indicated that hydroxy-urea can prolong survival time of affected animals

Sled-type motion on the nanometer scale : determination of dissipation and cohesive energies of C-60

The tribological properties of C-60 on the mesoscopic scale were investigated with a scanning force microscope, which allowed simultaneous measurements of normal and lateral forces under ultrahigh-vacuum conditions. islands of C-60, deposited on NaCl(001), could be moved by the action of the probing tip in a controlled way. Different modes of motion, such as translation and rotation, were observed. An extremely small dissipation energy of about 0.25 millielectron volt per molecule and a cohesive energy of 1.5 electron volts were determined in these nanometer-scale experiments. The corresponding shear strength of 0.05 to 0.1 megapascal was smaller by one order of magnitude than typical values of boundary lubricants. For C-60 on graphite, disruption of the islands was observed and collective motion of the islands could not be achieved. These results could find use in the field of nanotechnology; for example, C-60 islands could be developed into a sled-type transport system on the nanometer scale

Statics and dynamics of ferroelectric domains studied with scanning force microscopy

Scanning force microscopy for studying ferroelectric domain structures is applied. The force microscope was operated in the contact static mode (repulsive force regime) and in the noncontact dynamic mode (attractive force regime). These two techniques were applied to study cleavage faces of ferroelectric crystals of GASH (guanidinium aluminum sulfate hexahydrate) and TGS (triglycine sulfate) crystals. Using the contact mode, the positive and negative domains are revealed by opposite contrast. In the dynamic noncontact mode, the domain walls are revealed. The experimental setup allows in situ experiments to study the dynamics of ferroelectric domains. First results on the time dependence of the domains motion in TGS will be presented

Friction force microscopy on well defined surfaces

Friction force microscopy is implemented in ultrahigh vacuum conditions, Atomic-scale friction is observed on clean surfaces. The onset of atomic-scale stick-slip is observed and discussed in relation to the plucking model. Comparative measurements of AgBr(001) versus NaCl(001) and C-60 versus NaCl(001) demonstrate the material-specific contrast of friction. Contrast mechanisms are discussed in relation to these experiments. The role of the chemical nature of the tip is exemplified for the case of Si(111) 7 x 7, where wearless sliding is achieved with a PTFE-coated probing tip

Nanotribology : an UHV-SFM study on thin-films of C60 and AgBr

We performed scanning force microscopy (SFM) in ultrahigh vacuum (UHV) on C60 and AgBr thin films deposited on NaCl(001) substrates. The morphology of the initial growth stage and the nanotribological properties of these thin films are characterized and discussed. A novel experimental approach is presented where local friction coefficients are determined: the lateral (frictional) forces are measured as a function of normal load, controlled by an external ramp generator. The local friction coefficient can be extracted by means of the two-dimensional histogram technique. In the low load regime, friction coefficients of 0.15 +/- 0.02, 0.33 +/- 0.07 and > 0.03 were found between probing SiOx tip and C60, AgBr and NaCl, respectively. The two-dimensional histogram reveals significant details about the force regime of wear-less friction and the initial stage of wear on these thin films

Submicron contacts for electrical characterization of semiconducting WS2 thin films

We report a new method to characterize the local electronic properties of polycrystalline semiconducting thin films. A lattice of triangular gold electrodes, with a typical area of 0.2 mm2, is evaporated on a p-type WS2 film. With the help of a conductive atomic force microscope, the current voltage characteristics of the contacts established between the gold electrodes and the WS2 film are measured. A linear dependence of the current versus voltage is obtained on gold triangles in contact with grain edges. This indicates a high level of doping or degeneracy of the semiconductor at the grain edges. The electrodes deposited on flat WS2 crystallites form rectifying diodes with the underlying grains. Barrier heights of 0.56 0.74 eV and diode ideality factors between 1.15 and 2 are determined. Under illumination, open-circuit voltages up to 500 mV can be measured on some contacts. A short response time of the photocurrent is observed (100 ms), linked to trapping effectsat grain boundaries