Switching adhesion forces by crossing the metal-insulator transition in Magnéli-type vanadium oxide crystals.

Magnéli-type vanadium oxides form the homologous series V(n)O(2) (n) (-1) and exhibit a temperature-induced, reversible metal-insulator first order phase transition (MIT). We studied the change of the adhesion force across the transition temperature between the cleavage planes of various vanadium oxide Magnéli phases (n = 3 … 7) and spherical titanium atomic force microscope (AFM) tips by systematic force-distance measurements with a variable-temperature AFM under ultrahigh vacuum conditions (UHV). The results show, for all investigated samples, that crossing the transition temperatures leads to a distinct change of the adhesion force.

Spontaneous intracranial hypotension: case report with subdural hematomas, steroid dependency and clinical improvement after myelography.

Objective: In spontaneous intracranial hypotension (SIH), also known as spontaneous hypoliquorrhea, an abnormally low intracranial pressure leads to posture-dependent headaches similar to those observed after lumbar puncture. Although its etiology is not yet fully understood, it is now diagnosed more often as clinical awareness increases and the availability of MRI becomes more widespread.

Clinical Presentation: We report the case of a 42-year-old patient with SIH who developed bilateral subdural hematomas (SDH) and symptomatic diencephalic herniation requiring surgical evacuation.

Intraoperative landmarking of vascular anatomy by integration of duplex and Doppler ultrasonography in image-guided surgery. Technical note.

Background: The integration of ultrasound technology into neuronavigation systems has recently been the subject of reports by several groups. This article describes our preliminary findings with regard to the integration of data derived from intraoperative duplex (color mode) and Doppler ultrasonography into a neuronavigational data set. It was the aim of the study to investigate (1) whether the intraoperative landmarking of vessels that are outlined with ultrasound technology is possible and (2) whether such a technique might be of clinical interest for neurosurgical interventions.

Functional imaging with intraoperative ultrasound: detection of somatosensory cortex in dogs with color-duplex sonography.

Objective: To evaluate the capability of intraoperative color-duplex sonography to detect eloquent flow-activated areas and their anatomic relationship in dogs.

Methods: After craniotomy, the sensory cortex of eight dogs was identified by recording the highest amplitude detected with a grid electrode evoked with somatosensory evoked potential stimulation of the nervus ischiadicus. A 7.

In vivo droplet vaporization for occlusion therapy and phase aberration correction.

The objective was to determine whether a transpulmonary droplet emulsion (90%, <6 microm diameter) could be used to form large gas bubbles (>30 microm) temporarily in vivo. Such bubbles could occlude a targeted capillary bed when used in a large number density. Alternatively, for a very sparse population of droplets, the resulting gas bubbles could serve as point beacons for phase aberration corrections in ultrasonic imaging.