Transmission electron microscopy of fluorapatite-gelatine composite particles prepared using focused ion beam milling.

In this paper, synthetic fluorapatite-gelatine composite particles are prepared for transmission electron microscopy (TEM) studies using two methods based on focused ion beam (FIB) milling. TEM studies on the FIB-prepared specimens are compared with TEM observations on samples prepared using an ultramicrotome. The results show that ultramicrotome slicing causes significant cracking of the apatite, whereas the ion beam can be used to make high-quality, crack-free specimens with no apparent ion beam-induced damage. The TEM observations on the FIB-prepared samples confirm that the fluorapatite composite particles are composed of elongated, preferentially orientated grains and reveal that the grain boundaries contain many small interstices filled with an amorphous phase.

Selective specimen preparation for TEM observation of the cross-section of individual carbon nanotube/metal junctions

We present here an efficient method to prepare a transmission electron microscopy (TEM) specimen for selective observation of the cross-section of individual nanoscale structures. As a typical example, the cross-sectional TEM observation of a quasi-one-dimensional material - a nano-electronic component based on an individual carbon nanotube - is presented.

Rat locomotion and release of acetylcholinesterase.

In the substantia nigra acetylcholinesterase is released from the dopamine cells of the pars compacta independent of cholinergic transmission. In this study the effects of local and systemic amphetamine treatment were compared on acetylcholinesterase release in the rat substantia nigra in relation to concomitant behavior. Acetylcholinesterase release, measured "on-line" with a sensitive chemiluminescent system, was enhanced by amphetamine stimulation administered locally and could not be dissociated from simultaneous amphetamine-induced circling behavior. On the other hand, amphetamine administered systemically resulted in a general increase in locomotor behavior followed by a subsequent increase in acetylcholinesterase release. The alternative scenario of an initial rise in acetylcholinesterase release, subsequently followed by enhanced movement, was never seen. Hence, movement can enhance release of acetylcholinesterase from the substantia nigra, whereas "upstream" local nigral events can affect acetylcholinesterase release and movement simultaneously.