University of Westminster

About: University of Westminster is a education organization based out in London, United Kingdom. It is known for research contribution in the topics: Population & Politics. The organization has 2944 authors who have published 8426 publications receiving 200236 citations. The organization is also known as: Westminster University & Royal Polytechnic Institution.

The ventrolateral medulla and medullary raphe in sudden unexpected death in epilepsy

Abstract: Sudden unexpected death in epilepsy (SUDEP) is a leading cause of premature death in patients with epilepsy. One hypothesis proposes that sudden death is mediated by post-ictal central respiratory depression, which could relate to underlying pathology in key respiratory nuclei and/or their neuromodulators. Our aim was to investigate neuronal populations in the ventrolateral medulla (which includes the putative human pre-Botzinger complex) and the medullary raphe. Forty brainstems were studied comprising four groups: 14 SUDEP, six epilepsy controls, seven Dravet syndrome cases and 13 non-epilepsy controls. Serial sections through the medulla (from obex 1 to 10 mm) were stained for Nissl, somatostatin, neurokinin 1 receptor (for pre-Botzinger complex neurons) and galanin, tryptophan hydroxylase and serotonin transporter (neuromodulatory systems). Using stereology total neuronal number and densities, with respect to obex level, were measured. Whole slide scanning image analysis was used to quantify immunolabelling indices as well as co-localization between markers. Significant findings included reduction in somatostatin neurons and neurokinin 1 receptor labelling in the ventrolateral medulla in sudden death in epilepsy compared to controls (P < 0.05). Galanin and tryptophan hydroxylase labelling was also reduced in sudden death cases and more significantly in the ventrolateral medulla region than the raphe (P < 0.005 and P < 0.05). With serotonin transporter, reduction in labelling in cases of sudden death in epilepsy was noted only in the raphe (P ≤ 0.01); however, co-localization with tryptophan hydroxylase was significantly reduced in the ventrolateral medulla. Epilepsy controls and cases with Dravet syndrome showed less significant alterations with differences from non-epilepsy controls noted only for somatostatin in the ventrolateral medulla (P < 0.05). Variations in labelling with respect to obex level were noted of potential relevance to the rostro-caudal organization of respiratory nuclear groups, including tryptophan hydroxylase, where the greatest statistical difference noted between all epilepsy cases and controls was at obex 9-10 mm (P = 0.034), the putative level of the pre-Botzinger complex. Furthermore, there was evidence for variation with duration of epilepsy for somatostatin and neurokinin 1 receptor. Our findings suggest alteration to neuronal populations in the medulla in SUDEP with evidence for greater reduction in neuromodulatory neuropeptidergic and mono-aminergic systems, including for galanin, and serotonin. Other nuclei need to be investigated to evaluate if this is part of more widespread brainstem pathology. Our findings could be a result of previous seizures and may represent a pathological risk factor for SUDEP through impaired respiratory homeostasis during a seizure.

Digital alias-free signal processing in the GHz frequency range

Abstract: The advanced Information Technology we call Digital Alias-free Signal Processing (DASP) is discussed in this paper to draw attention to the facts that, first, this technique has already reached a considerable degree of maturity so that it can now be used as a widely applicable Digital Signal Processing (DSP) tool and, second, that it is especially competitive in the area of Microwave and Radio Frequency (RF) signal processing. Its utility arises from its applicability to digital processing of signals at frequencies considerably exceeding half of the mean sampling rate, which traditionally limit classical DSP applications.

From Agent Theory to Agent Construction: A Case Study

Abstract: There is a growing body of work that concentrates on theoretical aspects of agents and multi-agent systems, and a complementary body of work concerned with building practical systems. However, the two have typically been unrelated. This gap between the theory and practice of intelligent agents has only relatively recently begun to be addressed. In this paper we describe the construction of an agent simulation environment that is based strongly on a formal theory of agent systems, but which is intended to serve in exactly this way as a basis for practical development. The paper briefly introduces the theory, then describes the system and the simple reactive agents built with it, but most importantly shows how it reflects the theoretical framework and how it facilitates incremental agent design and implementation. Using this example as a case-study, some possibilities for a methodology for the development of agent systems are discussed.

Effect of dissolved oxygen tension and pH on the production of extracellular protease from a new isolate of Bacillus subtilis k2, for use in leather processing

Abstract: Scale-up of production of an alkaline protease, previously characterised from a new isolate of Bacillus subtilis for use as a bating enzyme in leather processing, is described Before large-scale commercial production of the protease is possible, characteristics of the growth of the bacterium and enzyme production in fermenters must be defined In 2 dm3 fermenters an optimal specific activity of 296×103 U g −1 cell dry weight was obtained after 60 h with the dissolved oxygen tension (DOT) kept above 10% and pH left uncontrolled Culture pH was 6 on inoculation, falling to 53 after 12 h before rising steadily to ∽8 at the end of fermentation DOT was maintained above 10% by agitation in the range 300 to 500 rpm The same criteria were adopted for scale-up to 20 dm3 but the increase in activity occurred 24 h later © 1999 Society of Chemical Industry