C-C Bond Lengths and Hybridization in some Cyclopropane Derivatives. GED Structure Studies of 1-Methyl-1-tert-butyl-cyclopropane and 1-Methyl-1-iso-propyl-cyclopropane

The molecular structures of 1-methyl-1-tert-butyl-cyclopropane and 1- methyl-l-iso-propyl-cyclopropane have been studied by gas-phase electron diffraction. The effects of hybridization and sterical overcrowding on the central C-C bond are discussed. Theoretical calculations (ab initio HF/6- 31G*; AM1;MM3) of the geometiy of a series of molecules of relevance for the problems treated, have been carried out

Kinetic studies of the hydrolysis of aromatic sulphonic anhydrides

We present a preliminary study of a thalamo-cortico-thalamic (TCT) implementation on SpiNNaker (Spiking Neural Network architecture), a brain inspired hardware platform designed to incorporate the inherent biological properties of parallelism, fault tolerance and energy efficiency. These attributes make SpiNNaker an ideal platform for simulating biologically plausible computational models. Our focus in this work is to design a TCT framework that can be simulated on SpiNNaker to mimic dynamical behaviour similar to Electroencephalogram (EEG) time and power-spectra signatures in sleep-wake transition. The scale of the model is minimised for simplicity in this proof-of-concept study; thus the total number of spiking neurons is approximately 1000 and represents a `mini-column' of the thalamocortical tissue. All data on model structure, synaptic layout and parameters is inspired from previous studies and abstracted at a level that is appropriate to the aims of the current study as well as computationally suitable for model simulation on a small 4-chip SpiNNaker system. The initial results from selective deletion of synaptic connectivity parameters in the model show similarity with EEG time series characteristics of sleep and wakefulness. These observations provide a positive perspective and a basis for future implementation of a very large scale biologically plausible model of thalamo-cortico-thalamic interactivity---the essential brain circuit that regulates the biological sleep-wake cycle and associated EEG rhythms