To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Ecstasy (3,4-methylenedioxymethamphetamine, MDMA) is an amphetamine derivative that is used recreationally and is now being tested in clinical trials for treatment of posttraumatic stress disorder. Ecstasy can damage serotonin neurones in brain of experimental animals; however, relevance of these findings to the human is debated.
To measure by positron emission tomography (PET) levels of binding to the serotonin transporter (SERT), a marker of serotonin neurones, in brain of chronic ecstasy users and in matched controls.
An estimate of brain SERT levels was obtained, using the PET tracer 11C-DASB, in 50 chronic (confirmed by drug hair testing) ecstasy users (mean age, 26 years; mean duration of drug use, 3.9 years; median drug withdrawal time, 38 days) and 50 (drug-hair negative) control subjects (mean age 26 years).
SERT binding levels in the ecstasy group were significantly decreased by 22 to 46% in frontal, temporal, cingulate, insular and occipital cortices, and by 23% in hippocampus. However, concentrations were distinctly normal in the SERT-rich caudate, putamen, ventral striatum and thalamus.
Our imaging data suggest that cerebral cortical SERT concentration is below normal in some ecstasy users for at least one month after last use of the drug. However, it remains to be established whether low SERT might have preceded drug use, reflects actual loss of brain serotonin neurones, or is causally related to any functional impairment in the ecstasy users. (Supported by US NIH NIDA DA017301).
Antarctic and Southern Ocean science is vital to understanding natural variability, the processes that govern global change and the role of humans in the Earth and climate system. The potential for new knowledge to be gained from future Antarctic science is substantial. Therefore, the international Antarctic community came together to ‘scan the horizon’ to identify the highest priority scientific questions that researchers should aspire to answer in the next two decades and beyond. Wide consultation was a fundamental principle for the development of a collective, international view of the most important future directions in Antarctic science. From the many possibilities, the horizon scan identified 80 key scientific questions through structured debate, discussion, revision and voting. Questions were clustered into seven topics: i) Antarctic atmosphere and global connections, ii) Southern Ocean and sea ice in a warming world, iii) ice sheet and sea level, iv) the dynamic Earth, v) life on the precipice, vi) near-Earth space and beyond, and vii) human presence in Antarctica. Answering the questions identified by the horizon scan will require innovative experimental designs, novel applications of technology, invention of next-generation field and laboratory approaches, and expanded observing systems and networks. Unbiased, non-contaminating procedures will be required to retrieve the requisite air, biota, sediment, rock, ice and water samples. Sustained year-round access to Antarctica and the Southern Ocean will be essential to increase winter-time measurements. Improved models are needed that represent Antarctica and the Southern Ocean in the Earth System, and provide predictions at spatial and temporal resolutions useful for decision making. A co-ordinated portfolio of cross-disciplinary science, based on new models of international collaboration, will be essential as no scientist, programme or nation can realize these aspirations alone.
Electron probe microanalysis (EPMA) is being utilized to characterize the composition of superconductors in the Bi-Sr-Ca-Cu-O system (BSCCO) that are doped with minor amounts of transition metal
s. Specifically, the Fe Group (Fe, Ru, Os), the Co Group (Co, Rh, Ir), the Ni Group (Ni, Pd, Pt), the Zn Group (Zn, Cd, Hg), and the other elements in the Cu Group (Ag, Au) can be used as dopants. These first long period ions in their common valence states have similar ionic radii, so only small lattice distortions are expected when other first period ions are substituted for Cu. Our research involves the systematic study of the effect of transition metal substitutions (for Cu) on the properties of the two high temperature superconductors, Bi2Sr2CaCu2O8+δ (2212) and Bi2Sr2Ca2Cu3O10+δ (2223).
Substitution for Cu with transition metal ions enables one to see what effect the changing d and s character of the ions have on the superconducting properties of these compounds.
Email your librarian or administrator to recommend adding this to your organisation's collection.