Positron demonstrated

In 1921, Irene Curie (1897-1956) began research at the Radium Institute. Five years later she married Frederic Joliot (1900-1958). a brilliant young physicist who was also an assistant at the Institute. In 1931, they began a research program in nuclear chemistry that led to several important discoveries and at least one near miss. The Joliot-Curies were the first to demonstrate induced radioactivity. They also discovered the positron, a particle that scientists had been seeking for many years. They narrowly missed finding another, more fundamental particle, the neutron. That honor went to James Chadwick in England. In 1935,... 

Positron annihilation spectroscopy (PAS) was first applied to investigate [Fe(phen)2(NCS)2] [77]. The most important chemical information provided by the technique relates to the ortho-positronium lifetime as determined by the electron density in the medium. It has been demonstrated that PAS can be used to detect changes in electron density accompanying ST or a thermally induced lattice deformation, which could actually trigger a ST [78]. 

Patients with combat-related PTSD compared to healthy controls had enhanced behavioral, biochemical, and cardiovascular responses to the a2 antagonist yohimbine, which stimulates central NE release (Southwick et al. 1993, 1997). Moreover, a positron emission tomography study demonstrated that PTSD patients have a cerebral metabolic response to yohimbine consistent with increased NE release (Bremner et al. 1997b). 

Be is the lightest nuclide that decays by electron capture and hence is the best nuclide to demonstrate whether or not the decay constant for electron capture depends on the chemical environment and pressure. (The decay constants for a-decay and p-decay through emission of an electron or a positron from the... 

We have demonstrated the use of generator produced Rb-82 as a readily available supply of a positron emitter for PET studies. 

Neuroanatomy. Abnormalities on positron emission tomography (PET) scans of neuronal activity of cortical projections to the basal ganglia have been confirmed by a number of investigators in OCD patients. Specifically, projections from the orbitofrontal—medial prefrontal cortex may be implicated in OCD. Such PET-demonstrated abnormalities in cortical projections to the basal ganglia may even be linked to the severity of symptoms in OCD patients, since they diminish as OCD patients improve, whether that improvement occurs after drag treatment or after behavioral therapy (see Fig. 5—53). 

A 1998 study using data from positron emission tomography or PET scans on humans also demonstrated that ketamine stimulates the release of dopamine, the brain s pleasure chemical. Most drugs of abuse spur the forced release of dopamine, reinforcing pleasurable associations in the user. 

Mills (1984) pointed out that it might soon be experimentally feasible to realize systems containing positrons which overlapped one with another, both spatially and temporally. This was due to the production of time-focussed beams and the prospects (since demonstrated) for brightness-enhanced, highly focussed beams. 

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