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Conductivities/Q-l cm-l from ca.to 800 [for Cu(TCNQ)] are obtained for salts, often novel, of the formulation M(TCNQ), or M(TCNQ), (solvent),, prepared by cathodic electrocrystallisation from tetracyanoquinodimethane (TCNQ) in the presence of metal (M) salts, where the M are

The anodic electropolymerisation of long-chain 3-substituted pyrroles and thiophenes gives highly conducting polymeric materials, some of which are soluble in common organic solvents in the conducting state.

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Although it is some five years since fullerenes were extracted in macroscopic quantities from the black, superficially amorphous sooty deposits produced by a carbon arc under helium, little is known in detail about the structure of the deposit or its electrical and magnetic properties. Here we provide evidence that this deposit, known as fullerene soot, is composed of defective networks of carbon atoms which do not have all valencies satisfied. We have studied these soots, before and after thermal annealing, using x-ray and electron diffraction, electron spin-resonance (ESR) spectroscopy, infra-red transmission and measurements of electrical conductivity. We find that localized states associated with such dangling bonds are removed from the soot on annealing and this process is accompanied by an ordering transition which modifies the electrical and magnetic properties. The fullerene soot particles appear to be encapsulated aggregates of highly defective carbon `onions'. Such metastable defective networks undergo a subtle ordering processes upon heat treatment which is accompanied by a rise in the electrical conductivity and a loss of paramagnetism due to the elimination of unsatisfied carbon atom valencies. Electrical conductivity and infra-red transmission measurements indicate that the centre of these `onions' is graphitic, with metallic properties. The temperature dependence of the electrical conductivity suggests that charge transport in both annealed and unannealed materials occurs by tunnelling between metallic islands in the sample. The ESR linewidth, arising from the spin centres in fullerene soots, is not significantly changed by exposure to oxygen. This suggests that the free radical centres in fullerene soots are extremely efficiently isolated from the atmosphere - presumably by encapsulation. This behaviour contrasts with that of amorphous carbons prepared by thermal decomposition of organic materials (chars). The ESR g-factors of the fullerene soots are lower than those of chars, which suggests that the radicals in fullerene soots have strong sigma character due to unsatisfied -type valencies. In this paper, a plausible structure and associated annealing mechanism for the fullerene soot is presented based on these experimental observations. .

SummaryControversy exists as to whether effective spinal anaesthesia can be achieved as quickly as general anaesthesia for a category-1 caesarean section. Sixteen consultants and three fellows in obstetric anaesthesia were timed performing spinal and general anaesthesia for category-1 caesarean section on a simulator. The simulation time commenced upon entry of the anaesthetist into the operating theatre and finished for the spinal anaesthetic at the end of intrathecal injection and for the general anaesthetic when the anaesthetist was happy for surgery to start. In the second clinical part of the study, the time from intrathecal administration to 'adequate surgical anaesthesia' (defined as adequate for start of a category-1 caesarean section) was estimated in 100 elective (category-4) caesarean sections. The median (IQR [range]) times (min:s) for spinal procedure, onset of spinal block and general anaesthesia were 2:56 (2:32 -3:32 [1:22 -3:50]), 5:56 (4:23 -7:39 [2:9 -13:32]) and 1:56 (1:39 -2:9 [1:13 -3:12]), respectively. The limiting factor in urgent spinal anaesthesia is the unpredictable time needed for adequate surgical block to develop.

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