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Results are presented for an electron impact study of ionization and fragmentation effects in Bi microclusters ranging in size from 1 to 63 atoms. Using results from both high-vacuum and gas condensation cluster sources, energy thresholds for the fragmentation of clusters larger than 20 atoms or so are identified and found to lie 5±1 eV above the corresponding ionization thresholds. The experimental distribution of net changes in intensity from fragmentation, for clusters from 3 to 63 atoms, has been fitted with a simple model in which it was necessary to assume (a) a strong peak in the fragmentation probability in the vicinity of ∼30 atoms and (b) a probability of ∼80% that the minor fragment retains the positive charge, contrary to expectations based on final energies. Ionization potentials are given for clusters up to n=38 atoms. These are found to show rough agreement with the metallic sphere model for n>5 atoms, i.e., behavior intermediate between that of simple metals and semiconductors. The great majority of clusters studied also exhibit second thresholds in their ionization curves, from 1.2 to 3.0 eV above the first onset. The interval between thresholds becomes nearly constant for n>10 atoms. We tentatively attribute this effect to structure in the filled electron states. [ABSTRACT FROM AUTHOR]

Presents a study which examined copper oxide superconductors using nuclear magnetic resonance and nuclear quadrupole resonance. Experimental procedures; Results of spin-lattice relaxation; Conclusion.

Background: Postoperative pain management is often limited by adverse effects such as nausea and vomiting. Adjuvant treatment with an inexpensive opioid-sparing drug such as ketamine may be of value in giving better analgesia with fewer adverse effects., Objectives: To evaluate the effectiveness and tolerability of ketamine administered perioperatively in the treatment of acute postoperative pain in adults., Search Strategy: Studies were identified from MEDLINE (1966-2004), EMBASE (1980-2004), the Cochrane Library (2004) and by handsearching reference lists from review articles and trials. The manufacturer of ketamine (Pfizer) provided search results from their in-house database, PARDLARS., Selection Criteria: Randomised controlled trials (RCTs) of adult patients undergoing surgery, being treated with perioperative ketamine or placebo. Studies where ketamine was administered in addition to a basic analgesic (such as morphine or NSAID) in one study group, and compared with a group receiving the same basic analgesic (but without ketamine) in another group, were also included., Data Collection and Analysis: Two independent reviewers identified fifty five RCTs for potential inclusion. Quality and validity assessment was performed by two independent reviewers. In the case of discrepancy, a third reviewer was consulted. Patient reported pain intensity and pain relief was assessed using visual analogue scales or verbal rating scales and adverse effects data were collated., Main Results: Thirty-seven trials were included (2240 participants). Eighteen trials were excluded.Twenty-seven of the 37 trials found that perioperative subanaesthetic doses of ketamine reduced rescue analgesic requirements or pain intensity, or both. Quantitative analysis showed that treatment with ketamine reduced 24 hour PCA morphine consumption and postoperative nausea or vomiting (PONV). Adverse effects were mild or absent., Authors' Conclusions: Ketamine in subanaesthetic dose (that is a dose which is below that required to produce anaesthesia) is effective in reducing morphine requirements in the first 24 hours after surgery. Ketamine also reduces postoperative nausea and vomiting. Adverse effects are mild or absent.

Background: Chronic pain is a complex, multidimensional phenomenon. Medical intervention has often little effect., Material and Methods: The case histories of 100 patients evaluated by the multidisciplinary pain clinic team at Haukeland University Hospital in Bergen, Norway were examined., Results: 44% of the patients reported serious trauma long before the development of pain., Interpretation: Chronification of pain appears to be related to childhood trauma.

Long-term opioid therapy results in physical dependency. Therefore abrupt cessation of opioid treatment may cause acute abstinence symptoms. The doses of opioids should always be reduced gradually, even when other treatment options give good pain relief. Patients receiving long-term treatment with opioids become more sensitive to the opioid antagonist naloxone. Inappropriate use of naloxone in these patients can also result in acute abstinence symptoms. Opioid treatment is limited by toxic side effects, and the problem can be solved by changing the opioid. The author describes three cases to illustrate these problems.