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Showing papers by "City University London published in 1974"


Journal ArticleDOI
TL;DR: In this paper, a reliability model with the usual continuous random variable representation of the working times of the system between failures is proposed with a probabilistic repair rule via a Bayesian argument, in order to simulate decay (or improvement) of reliability in time.
Abstract: A reliability model is proposed with the usual continuous random variable representation of the working times of the system between failures. The model utilizes a probabilistic repair rule, via a Bayesian argument, in order to simulate decay (or improvement) of reliability in time.

80 citations


Journal ArticleDOI
TL;DR: The results are compatible with the hypothesis that Gilbert9s syndrome is a manifestation of a relative deficiency of hepatic bilirubin glucuronyl transferase, and differs from congenital non-haemolytic jaundice only in severity.
Abstract: 1. The clearance of a tracer dose of [ 14 C]bilirubin from the plasma was studied in patients with Gilbert9s syndrome, congenital non-haemolytic jaundice, haemolytic jaundice and in normal subjects. Clearance was significantly impaired in the patients with Gilbert9s syndrome and in those with congenital non-haemolytic jaundice when compared with the normal subjects, and was normal in the patient with haemolytic jaundice. 2. Treatment for 2 weeks with phenobarbitone (180 mg/day) lowered the plasma bilirubin concentration and improved all indices of plasma clearance of the isotope in patients with Gilbert9s syndrome, so that they became indistinguishable from those of normal subjects. The improvement in plasma [ 14 C]bilirubin clearance in these patients was associated with modest increases in hepatic bilirubin glucuronyl transferase in some subjects. 3. Phenobarbitone treatment improved plasma bilirubin concentrations and plasma [ 14 C]bilirubin clearance in patients with congenital non-haemolytic jaundice, so that they resembled those seen in patients with untreated Gilbert9s syndrome. Despite this improvement hepatic bilirubin glucuronyl transferase activity remained undetectable. 4. These results are compatible with the hypothesis that Gilbert9s syndrome is a manifestation of a relative deficiency of hepatic bilirubin glucuronyl transferase, and differs from congenital non-haemolytic jaundice only in severity.

42 citations


Journal ArticleDOI
TL;DR: It is perhaps surprising that changes in noradrenaline were comparable to those of adrenaline, but stress appears to increase the excretion of both catecholamines (Levi, 1968), which is likely to provide the more useful measurement of pain.
Abstract: Measurement of the excretion of catecholamines appears to provide an indirect but objective measure of pain which may be useful in the assessment of analgesic drugs. There is a large individual variation and the method is likely to be useful only in crossover trials when the patient provides his own control. The differences in treated and untreated patients are not large and urine collections for at least three days are likely to be required to detect them. In a previous experiment, there were no significant differences in treated and untreated patients with urine collected for three 12 h periods overnight. In this study, a variety of treatments was used and in all cases there was a good response to treatment. Less marked pain relief might be undetectable or require longer periods of collection. The findings of this study could also be explained by a direct action of analgesic and anti-inflammatory drugs on some aspect of catecholamine metabolism, which must be considered when the method is applied to individual compounds. It is perhaps surprising that changes in noradrenaline were comparable to those of adrenaline, but stress appears to increase the excretion of both catecholamines (Levi, 1968). Because noradrenaline is excreted in much larger amounts, it is likely to provide the more useful measurement of pain.

36 citations


Journal ArticleDOI

31 citations


Journal ArticleDOI
TL;DR: In this paper, the ultrastructure of conjunctival nerve fibres was studied in control material from two species of monkey and the combined results of electron-microscopy of control and experimental material suggested that nerve fibers from different sources innervating the conjunctiva had ultrastructurally distinct terminals.
Abstract: The ultrastructure of conjunctival nerve fibres was studied in control material from two species of monkey. Nerve fibres reached the conjunctiva either in small nerves or in the adventitia of arterioles. A few myelinated nerve fibres were found within the nerves but the great majority of their fibres were unmyelinated. Bundles of unmyelinated nerve fibres were found in the interstices of the lamina propria up to the epithelial basement membrane and nerve fibres were traced into the epithelium. Other unmyelinated nerve fibre bundles lay adjacent to the walls of capillaries. Nerve fibre terminals exhibited varicosities and three types of terminals were recognised; those having varicosities packed with mitochondria, those having varicosities containing vesicles without any small granules and those having varicosities with vesicles, some with small granules. Following experimental nerve lesions induced changes were observed in the nerve fibres, and from these changes it was determined that nerve fibres from three sources were present in the conjunctiva. Nerves and interstitial nerve fibre bundles contained ophthalmic and pterygopalatine nerve fibres, from which the epithelium was supplied. Arteriolar nerve fibre bundles contained superior cervical and pterygopalatine nerve fibres which were joined by ophthalmic nerve fibres in capillary nerve fibre bundles. The combined results of electron-microscopy of control and experimental material suggested that nerve fibres from different sources innervating the conjunctiva had ultrastructurally distinct terminals.

29 citations


Journal ArticleDOI
TL;DR: In this paper, an examination is made of some methods for determining lower confidence limits for the reliability of series systems using binomial subsystem test data, and several approximate methods compare favorably with exact methods.
Abstract: An examination is made of some methods for determining lower confidence limits for the reliability of series systems using binomial subsystem test data. Key test results form the basis of a theoretical and numerical study which shows that several approximate methods compare favorably with exact methods.

27 citations


Journal ArticleDOI
TL;DR: In this article, a detailed analysis of the combustion in binary mixtures of n -decane and 2,2,5-trimethylhexane has been carried out and it has been shown that branched alkane has little effect on the slow combustion/cool flame boundary but as n-decane is further replaced by the nonane isomer, there is a progressive increase in the limiting temperature and pressure required for spontaneous ignition.

22 citations


Journal ArticleDOI
TL;DR: In this article, a wideband transducers for pulse-echo systems can be produced, and a spectrum analysis of the ultrasonic pulses is carried out by a novel, inexpensive spectrum analyser.

20 citations



Journal ArticleDOI
TL;DR: In this article, a single oxygen/glucose cell consisting of a platinum black on platinum-mesh electrode (cathode) and a platinum-black on porous graphite electrode (anode) was tested in vitro and in vivo in the rat.
Abstract: A biological fuel cell such as an oxygen/glucose cell has been considered to be an ideal power source for implantable cardiac pacemakers and similar devices. This study is mainly concerned with the development of a single oxygen/glucose cell, which can be implanted inside the body fluids with the simultaneous presence of oxidant and fuel(s). Present results ofin vitro experiments with a single oxygen/glucose cell consisting of a platinum black on platinum-mesh electrode (cathode) and a platinum black on porous-graphite electrode (anode) have shown that cell performance was markedly increased after glucose addition. Half-cell testings by means of a potentiostat coupled to a linear sweep generator also demonstrated that the anode current of a platinised graphite electrode after glucose was over 3 mA/cm2. It was also found that a steady and continuous power output of 20 μW/cm2 could be generated from the above oxygen/glucose cell. When the cell was testedin vivo in the rat. the continuous power output was steady at 3·3 μW/cm2. The present study also investigated the possibility of generating electricity from an oxygen concentration cell and an oxygen/hydrogen cell. It was concluded that a platinum black on porous graphite electrode offers promise as a specific electrode for glucose oxidation. An oxygen/hydrogen cell could also provide a long termin vivo power supply provided the Pd-H electrode is properly encapsulated. The significance of the present study in relation to the development of biological power sources is discussed, and the importance of fundamental investigation for the development of a specific electrode is emphasised.

17 citations


Journal ArticleDOI
TL;DR: In this paper, the specific heat of platinum in the temperature range 1200 to 1900 K has been measured by a temperature modulation method, and the results indicate that, under the conditions of modulation experiments, internal vacancy source/sinks operate at less than ideal efficiency.
Abstract: The specific heat of platinum in the temperature range 1200 to 1900 K has been measured by a temperature modulation method. In this, the light emitted by a specimen of 50 μm diameter wire heated by superimposed ac and dc was used to study the temperature modulation. The modulation frequencies used (100 to 1000 Hz) are significantly higher than the frequencies (30 Hz) used in previous studies, and the absence of any detectable frequency dependence of the specific heat is interpreted as showing that the vacancy contribution to the specific heat is less than 1% in the temperature range covered. The observed upward curvature of the graph of specific heat against temperature is interpreted as an effect due to the lattice specific heat. A comparison of the specific heats measured by emitted light and electrical resistance modulation methods is made, and the differences between them (≈5 to 10%) are interpreted as an effect of vacancy relaxation on the temperature coefficient of resistance. The results indicate that, under the conditions of modulation experiments, internal vacancy source/sinks operate at less than ideal efficiency. Die spezifische Warme von Platin wurde im Temperaturbereich zwischen 1200 und 1900 K mit einer Temperaturmodulationsmethode gemessen. Bei dieser Methode wurde zur Untersuchung der Temperaturmodulation Licht verwandt, das von einer Probe in Form eines Drahtes von 50 μm Durchmesser emittiert wurde, der durch einen Gleichstrom dem ein Wechselstrom uberlagert war, beheizt wurde. Die verwendeten Modulationsfrequenzen (100 bis 1000 Hz) sind bedeutend hoher als die Frequenzen (30 Hz), die in vorhergehenden Untersuchungen angewendet wurden. Das Fehlen irgendeiner mesbaren Frequenzabhangigkeit der spezifischen Warme wird dahingehend gedeutet, das der Beitrag der Leerstellen zur spezifischen Warme in dem uberstrichenen Temperaturbereich kleiner als 1% ist. Der beobachtete Anstieg des Gradienten der spezifischen Warme als Funktion der Temperatur wird als ein Effekt gedeutet, der auf die spezifische Warme des Gitters zuruckzufuhren ist. Es wird ein Vergleich angestellt zwischen der spezifischen Warme gemessen mit der Modulationsmethode des emittierten Lichts und der des elektrischen Widerstandes. Die Unterschiede zwischen beiden Ergebnissen (≈5 bis 10%) werden auf den Einflus der Relaxation der Leerstellen auf den Temperaturkoeffizienten des Widerstandes zuruckgefuhrt. Die Ergebnisse zeigen, das innere Quellen bzw. Senken fur Leerstellen unter den Bedingungen von Modulationsexperimenten mit einer geringeren als der idealen Wirksamkeit arbeiten.

Journal ArticleDOI
TL;DR: The human body is surrounded by an enveiope of upward-moving warm air which forms a natural convection boundary layer which has been used to visualise this airflow and this visualisation has been complemented by measurements of temperature and velocity within the flow and local convective heat transfer rates at the skin surface.
Abstract: The human body is surrounded by an enveiope of upward-moving warm air which forms a natural convection boundary layer. A Schlieren optical system has been used to visualise this airflow and this visualisation has been complemented by measurements of temperature and velocity within the flow and local convective heat transfer rates at the skin surface.

Journal ArticleDOI
01 Jun 1974
TL;DR: In this article, the results of two-level block program tests on 2L65 aluminium alloy at four values of constant principal stress ratio and at several combinations of two different principal stress ratios are presented and discussed with reference to cumulative damage criteria developed for the case of uniaxial fatigue stress.
Abstract: Previous investigations into cumulative damage fatigue under uniaxial stress are discussed in conjunction with the parameters relevant to the present experimental investigation. The results of two-level block programme tests on 2L65 aluminium alloy at four values of constant principal stress ratio and at several combinations of two different principal stress ratios are presented and discussed with reference to cumulative damage criteria developed for the case of uniaxial fatigue stress.

Journal ArticleDOI
TL;DR: In this article, the chemical shift of the NH protons for a series of monomethyl, dimethyl- and trimethyl- substituted 2- and 4- quinolones has been studied.
Abstract: The chemical shift of the NH protons for a series of monomethyl-, dimethyl- and trimethyl- substituted 2- and 4- quinolones has been studied. Compounds with an 8-methyl substituent exhibit a characteristic upfield shift which is considered to be due to a reduction in hydrogen bonding as a result of steric effects. The application of this effect to the identification of alkyl substituted quinolones and some natural products is discussed.


Journal ArticleDOI
TL;DR: In this paper, D.c. polarography, i-t curves, chronopotentiometry and linear sweep polarography have been used to examine the kinetics of the Cd 2+ /Cd(Hg) reaction in Ca(NO 3 ) 2 ·4H 2 O at 50°C.

Journal ArticleDOI
TL;DR: In this paper, Tantram charts the development of fuel cells from early laboratory experiments to the highly efficient, but expensive cells used in the Apollo space programme and assesses their future commercial prospects.

Journal ArticleDOI
TL;DR: In this article, the magnetic phase transition in disordered alloys is discussed on the basis of a phenomenological Landau theory and the critical concentration of disordered Pd-Ni alloys was found to be lower than that obtained previously for a regular lattice.

Journal ArticleDOI
TL;DR: In the course of an investigation into the reactions of ethynyl radicals with alkynes, monobromoethyne and certain polyalkynes, their infra-red spectra were recorded.
Abstract: In the course of an investigation into the reactions of ethynyl radicals with alkynes1, monobromoethyne and certain polyalkynes were synthesized and their infra-red spectra were recorded. Although ...

Journal ArticleDOI
TL;DR: Experiments have made in a laminar flow channel and in the flow over a full-sized heated model of the human form to visualise and analyse the trajectories of particles such as dust, skin scales, pollens and spores.
Abstract: The natural convection boundary layer surrounding the human body is capable of transporting particles such as dust, skin scales, pollens and spores and provides a link in the chain of airborne infection. Experiments have made in a laminar flow channel and in the flow over a full-sized heated model of the human form to visualise and analyse the trajectories of these particles.

Journal ArticleDOI
01 Apr 1974-Futures
TL;DR: In this article, the authors explore the relevance of some of the methodologies of systems engineering to problems in the social sciences, especially the dynamics of domestic and international conflict, and describe an initial exercise in modelling domestic conflict in terms of state equations (system dynamics).

Journal ArticleDOI
A. Davies1
TL;DR: Effects of clock drift on the performance of a discretetime control system for synchronizing all the clocks in a digital communications network are shown by a detailed analysis of the dynamic behavior of the simple case of a two-node network.
Abstract: Effects of clock drift on the performance of a discretetime control system for synchronizing all the clocks in a digital communications network are shown by a detailed analysis of the dynamic behavior of the simple case of a two-node network. With a unidirectional frequency drift of one or both oscillators, it is shown that the buffer stores eventually overflow. A more general linear control scheme is also discussed.

Patent
01 Jul 1974
TL;DR: In this paper, the metal nitrito compounds are provided having at least one nitrito group covalently bonded to a metal atom and characterized by being capable of reversibly forming additional compounds with molecular oxygen.
Abstract: Novel metal nitrito compounds are provided having at least one nitrito group covalently bonded to at least one metal atom and characterized by being capable of reversibly forming additional compounds with molecular oxygen The metal nitrito compounds are of general interest for carrying out chemical reactions

Journal ArticleDOI
TL;DR: In this article, the authors propose a framework for the development of the accountant's/auditor's traditional role and for a means of communication between interest groups within and without the enter-prise.
Abstract: Business enterprise today is being called upon to exercise significantly wider “social responsibility” than has traditionally been the case. As a result, individuals, communities and national governments are beginning to call for statements of “social account” which reflect a company's performance in the eyes not only of financial shareholders, but also of other stakeholders in the community at large. This paper, therefore, attempts to extend fundamental accounting principles, which have traditionally embraced only monetary stocks and flows, towards physical, social and psychological exchanges. It therefore provides a foundation both for the development of the accountant's/auditor's traditional role and for a means of communication between interest groups within and without the enter-prise. The paper does not attempt to develop thoroughgoing quantitative measures to the same degree of specificity as conventional financial accounts; rather it aims to develop a novel framework, to which both management practitioners and theorists may apply their own specific refinements.






Book ChapterDOI
01 Jan 1974