Showing papers by "Queen's University Belfast published in 1977"
TL;DR: Post-concussion symptoms were more frequent in women, in those injured by falls, and in those who blamed their employers or large impersonal organisations for their accidents.
280 citations
TL;DR: Cell-free extracts of benzonitrile-grown cells contain an enzyme that catalyses the conversion of benzoneitrile directly into benzoic acid without intermediate formation of benzamide, and studies with different substrates indicate that the nitrilase is specific for nitrile groups directly attached to the benzene ring.
Abstract: 1. An organism utilizing benzonitrile as sole carbon and nitrogen source was isolated by the enrichment-culture technique and identified as a Nocardia sp. of the rhodochrous group. 2. Respiration studies indicate that nitrile degradation proceeds through benzoic acid and catechol. 3. Cell-free extracts of benzonitrile-grown cells contain an enzyme that catalyses the conversion of benzonitrile directly into benzoic acid without intermediate formation of benzamide. 4. This nitrilase enzyme was purified by DEAE-cellulose chromatography and gel filtration on Sephadex G-100 in the presence and absence of substrate. The purity of the enzyme was confirmed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and isoelectric focusing on polyacrylamide gel. 5. The enzyme shows a time-dependent substrate-activation process in which the substrate catalyses the association of inactive subunits of mol.wt. 45000 to form the polymeric 12-unit active enzyme of mol.wt. 560000. The time required for complete association is highly dependent on the concentration of the enzyme, temperature and pH. 6. The associated enzyme has a pH optimum of 8.0 and Km with benzonitrile as substrate of 4mm. The activation energy of the reaction as deduced from the Arrhenius plot is 51.8kJ/mol. 7. Enzyme activity is inhibited by thiol-specific reagents and several metal ions. 8. Studies with different substrates indicate that the nitrilase is specific for nitrile groups directly attached to the benzene ring. Various substituents in the ring are compatible with activity, though ortho-substitution, except by fluorine, renders the nitrile invulnerable to attack. 9. The environmental implications of these findings and the possible significance of the enzyme in the regulation of metabolism are discussed.
184 citations
TL;DR: Rates of enzymic attack on various substrates indicated that the nitrilase has a fairly broad specificity and that the fungus probably plays an important role in the biodegradation of certain nitrilic herbicides in the environment.
Abstract: 1. A strain of the fungus Fusarium solani able to use benzonitrile as sole source of carbon and nitrogen was isolated by elective culture. 2. Respiration studies indicate that the nitrile, after degradation to benzoate, is catabolized via catechol or alternatively via p-hydroxybenzoate and 3,4-dihydroxybenzoate. 3. Cell-free extracts of benzonitrile-grown cells contain an enzyme mediating the conversion of benzonitrile into benzoate and ammonia. 4. The nitrilase enzyme was purified by DEAE-cellulose chromatography, (NH4)2SO4 precipitation and gel filtration on Sephadex G-200. The homogeneity of the purified enzyme preparation was confirmed by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and isoelectric focusing on polyacrylamide gel. 5. The enzyme showed a broad pH optimum between pH7.8 and 9.1 and a Km with benzonitrile as substrate of 0.039mm. The activation energy of the reaction deduced from an Arrhenius plot was 48.4kJ/mol. 6. The enzyme was susceptible to inhibition by thiol-specific reagents and certain heavy metal ions. 7. Gel filtration gave a value of 620000 for the molecular weight of the intact enzyme. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis demonstrated that the enzyme was composed of eight subunits of mol.wt. 76000. 8. Rates of enzymic attack on various substrates indicated that the nitrilase has a fairly broad specificity and that the fungus probably plays an important role in the biodegradation of certain nitrilic herbicides in the environment.
155 citations
TL;DR: The compensation effect remains largely an empirical method of classifying kinetic observations and this has not been developed into a theoretical representation capable of predicting activities and patterns of reactivity in hitherto untested catalytic processes.
Abstract: Publisher Summary This chapter discusses the compensation effect in heterogeneous catalysis that expresses the existence of interrelated kinetic behavior within a group of rate processes. The chapter focuses on the interrelation between kinetic characteristics and the chemistry of the participating surface rate processes. The chapter discusses the theoretical models and statistical methods used in the recognition of compensation phenomena. The chapter illustrates reported examples of compensation behavior and describes new instances of the effect that became apparent while making the present search of published kinetic data. A semiquantitative statistical analysis of these trends has been undertaken to provide a common basis for comparisons and to attempt to define criteria that enable meaningful relationships to be recognized. The compensation effect remains largely an empirical method of classifying kinetic observations and this has not been developed into a theoretical representation capable of predicting activities and patterns of reactivity in hitherto untested catalytic processes. Development of the usefulness of the correlation necessarily requires reexamination of many of the basic tenets of heterogeneous kinetic behavior.
146 citations
TL;DR: High levels of circulating insulin may have a role in the development of atherosclerosis because insulin has the ability to promote changes in the artery which, in the long term, may progress to Atherosclerosis.
108 citations
104 citations
TL;DR: Azzam and Bashara as mentioned in this paper presented an ellipsometry and polarized light for the first time in the context of polarizing light and ellipsology. Pp. xvii + 529.
Abstract: Ellipsometry and Polarized Light. By R. M. A. Azzam and N. M. Bashara. Pp. xvii + 529. (North-Holland: New York, Amsterdam and Oxford, 1977.) Dfl.180; $37.50.
101 citations
TL;DR: In this paper, the authors used a sine-generated curve to predict bed topography and grain size for steady, non-uniform flow in non-circular bends.
Abstract: Bed topography and grain size are predicted for steady, uniform flow in circular bends by consideration of the balance of fluid, gravity and frictional forces acting on bed load particles. Uniform flow pattern is adequately described by conventional hydraulic equations, with bed shear defined as that effectively acting on bed load grains. This analysis is used as a basis to predict bed topography and grain size for steady, non-uniform flow in non-circular bends (represented by a ‘sine-generated’ curve). The non-uniform flow pattern is calculated using the method of Engelund (1974a). Equilibrium bed form, hence sedimentary structure, is found by comparison of existing flow conditions with one of the schemes describing the hydraulic stability limits of the various bed forms.
The model was compared with bankfull flow observations from a channel bend on the River South Esk, Scotland. Theoretical bed topography and velocity distribution were very close to the observed data. However, bed shear stress showed only a broad agreement, probably because of the use a constant friction coefficient value. Mean grain size distribution showed good agreement, but theory did not account adequately for gravel sizes in the talweg region and on the upstream, inner part of the bar, possibly due to theoretical underestimation of effective bed shear. Bed form and sedimentary structure are predicted well using the familiar stream power-grain size scheme.
The behaviour of the model under unsteady uniform flow conditions in circular bends was analyzed, and suggests that any variation of grain size and bed topography with stage is likely to be limited to deeper parts of the channel.
97 citations
TL;DR: The study suggests that pheromones interact with cognitive and affective responses elicited by, and dependent on, the people assessed and their sex.
92 citations
TL;DR: In this article, 13C NMR spectra were obtained for polymers made by ring-opening polymerization of cyclopentene and bicyclo[2.2]hept-2-ene respectively.
Abstract: 13C NMR spectra were obtained for polymers made by ring-opening polymerization of cyclopentene and bicyclo[2.2.1]hept-2-ene respectively. The fraction of cis double bonds could be determined with much greater precision from 13C NMR spectra than from IR spectra and varied from 0,66 to 0,31 for the samples of poly(1-pentenylene), (2), and from 1,0 to 0,14 for the samples of poly(1,3-cyclopentylenevinylene), (4). This is the first time an all-cis polymer of 4 has been reported.
The spectra of 2 showed a cis (upfield) and trans (downfield) peak for each of CH and α-CH2, but only one peak for β-CH2. The spectra of 4 showed multiple fine structure, the main splittings corresponding to a cis (upfield) and trans (downfield) peak for α-CH, and a reverse line order for the other three carbons; subsidiary splittings were observed for all but the olefinic carbons, interpreted in terms of sensitivity of the chemical shifts to the cis/trans structure at the next nearest double bond. A complete interpretation of the line orders in 4 is given in terms of steric compression effects. The possibility that ring tacticity accounts for some of the fine structure cannot be entirely discounted.
The stereochemistry of 4 is discussed in relation to the four possible modes of addition of monomer to a carbene chain carrier during polymerization.
91 citations
TL;DR: The reproductive strategies exhibited by Cerastoderma, Modiolus, and Mytilus in Strangford Lough are considered in relation to population stability and to the different patterns of mortality which characterise these species in their respective local habitats.
Abstract: This paper examines the reproductive cycles of three ecologically important marine bivalves-Modiolus modiolus (L.), Cerastoderma edule (L.), and Mytilus edulis L. in Strangford Lough, Northern Ireland over a period of almost five years.Whilst Modiolus does not appear to become sexually mature until it is several years old, Mytilus and Cerastoderma can reproduce in their first and second years of life respectively. In Cerastoderma and Modiolus sexual maturity is preceded by a period of rapid somatic growth.The subtidal Modiolus population remained in a more or less fully ripe condition virtually throughout the period of this investigation suggesting that this particular population lacked any marked cyclical reproductive activity. We interpret this as evidence of slow but almost continuous release of gametes throughout much of the year, a suggestion which is supported by recruitment data. A small intertidal population of Modiolus in Belfast Lough monitored over a period of two years exhibited a much more seasonal cycle. Here spawning occurred mainly during the autumn and winter. These data suggest that localised environmental factors are exceedingly important in controlling the annual reproductive cycle of this species. Cerastoderma from the mid-tidal sand flats ripened rapidly during the spring and spawned over a relatively restricted period in the summer. In Strangford Lough Mytilus occurs predominantly in the low-shore and while it spawns mainly in the spring and summer the annual cycle is considerably more protracted and variable than in Cerastoderma.Variations in the duration of the spawning periods in these bivalves can perhaps be explained in terms of both environmental stability and the immediate physical conditions experienced by these particular populations. The reproductive strategies exhibited by Cerastoderma, Modiolus, and Mytilus in Strangford Lough are considered in relation to population stability and to the different patterns of mortality which characterise these species in their respective local habitats.
TL;DR: The EEG results showed transcendental meditation to be a method of holding the mediator's level of consciousness at stage 'onset' sleep, and no evidence could be found to suggest that meditation produced a hypometabolic state beyond that produced by muscle relaxation.
TL;DR: In this article, the R-matrix method is used to determine the collisional excitation cross sections between the 2s2 1Se, 2s 2p 3Po, 1Po and the 2p2 3Pe, 1De, 1Se target eigenstates of the beryllium isoelectronic sequence.
Abstract: The R-matrix method is being used to determine the collisional excitation cross sections between the 2s2 1Se, 2s2p 3Po, 1Po and the 2p2 3Pe, 1De, 1Se target eigenstates of the beryllium isoelectronic sequence. The first results for the 2s2 1S3-2s2p 3Po and 2s2 1Se-2s2p 1Po transitions for C III and O V are presented and compared with earlier distorted-wave and close-coupling results. The results indicate that the use of accurate target eigenstates and a more accurate treatment of the collision problem may change the cross sections by as much as 20% from earlier work.
TL;DR: The smooth muscle cell plays an important role in the process of atherogenesis, proliferating in the arterial intima and becoming filled with lipid during the course of the disease, and the effect of insulin and glucose on sterol synthesis in cultured rat arterial smooth muscle cells was studied.
TL;DR: Analysis of the additional properties of these beta adrenoceptor‐blocking drugs revealed that both practolol and oxprenolol have intrinsic sympathomimetic activity (ISA), whereas propranolol and sotalol do not and ISA would appear to appear to be demonstrated in man by flattening of the dose‐response curves with exercise.
Abstract: Dose-response curves for propranolol and oxprenolol were studied in healthy volunteers, with a standardized excercise test and percentage reduction in excercise heart rate (EHR) as the index of drug effect. The dose-response curves obtained were compared with similar curves previously reported for sotalol, practolol, and atenolol with identical experimental methods. Two distinct types of response were identified: in the first, shown by propranolol and sotalol, increasing doses of the beta adrenoceptor-blocking drug continued to produce increasing effects to the limits of the dose levels examined; with the second (oxprenolol and practolol), increasing the dose initially resulted in substantial increase in effect but subsequently larger doses produced almost no increase in effect. Consideration of the additional properties of these beta adrenoceptor-blocking drugs revealed that both practolol and oxprenolol have intrinsic sympathomimetric activity (ISA), whereas propranolol and sotalol do not. In addition, practolol is cardioselective. Further investigation of the possible influence of ISA or cardioselectivity on beta adrenoceptor-blocking activity was undertaken by studying the effects of combinations of drugs on EHR. Sotalol produced greater effect when given 2 hr after sotalol, oxprenolol, practolol, or atenolol. When oxprenolol was given after sotalol or oxprenolol, or practolol was given after sotalol or practolol, there was no further increase in percentage reduction in EHR. When atenolol was given, the combinations of sotalol and atenolol together with two doses either of sotalol or atenolol all induced increases and similar final percentage reductions in EHR. Thus atenolol induces effects like those of sotalol, which are quite different from those of oxprenolol or practolol. The presence or absence of ISA would appear to be the important difference between these two groups of drugs: ISA would, therefore, appear to be demonstrated in man by flattening of the dose-response curves with exercise.
TL;DR: The number of apoptotic bodies found in the small intestine of control non-fasted rats was low and the crypt region of zinc-deficient rats and were present in very large numbers in half the animals examined.
Abstract: The number of apoptotic bodies found in the small intestine of control non-fasted rats was low. Apoptotic bodies were found in the crypt region of zinc-deficient rats and were present in very large numbers in half the animals examined. Increased numbers of apoptotic bodies were found in the crypt and fundic regions of fasted rats. The failure of cellular DNA synthesis which may occur in both zinc deficiency and fasting is considered as a possible cause of cell death by apoptosis.
TL;DR: The responses of a population of Oystercatchers to their own depletion of their prey, the edible cockle Cerastoderma edule, have been examined in Strangford Lough, Northern Ireland and are seen as consistent with Royama's profitability theory.
Abstract: The responses of a population of Oystercatchers to their own depletion of their prey, the edible cockle Cerastoderma edule, have been examined in Strangford Lough, Northern Ireland., Cockle stocks were severely depleted each winter as a result of predation by Oystercatchers and about half the birds present in October in the main study area had left by March: the reduction was greater when the initial population of Oystercatchers was high than when it was low. Oystercatchers were initially widespread around the Lough but tended to aggregate by January into a few good sites. Within each site annual differences in the location of feeding effort were correlated with year to year variation in the location of second winter cockles.
TL;DR: It is discovered that calls of similar structure regularly occur without social stimulation and in a daily pattern controlled by the light–dark cycle, which may help in the maintenance of other behaviour patterns.
Abstract: CALLS of about 22 kHz occur during two kinds of social interaction among rats, Rattus norvegicus: they are produced by submissive animals in agonistic encounters1 and by males after ejaculation2,3 I have now discovered that calls of similar structure regularly occur without social stimulation and in a daily pattern controlled by the light–dark cycle Such ‘spontaneous’ 22-kHz calls may help in the maintenance and development of other behaviour patterns
TL;DR: In this paper, an absolute radiometric dating technique involving the investigation of all probable sources of error was proposed. But the accuracy of the radiometric dates was not improved by using a floating North of Ireland tree-ring chronology.
Abstract: Attempts to produce a calibration curve for the radiocarbon timescale by analysis of known age materials have highlighted the inaccuracies of conventional radiocarbon dating methods The resulting ambiguities have caused a loss of confidence in radiocarbon dating particularly among European pre-historians We describe here an absolute radiometric dating technique involving the investigation of all probable sources of error Accurate measurements were made with an overall precision of less than 25 yr standard deviation, on a floating North of Ireland tree-ring chronology
TL;DR: Oral lorazepam in doses of 2.5-5.0 mg was a reliable, effective sedative which could be recommended for routine preanaesthetic medication, provided rapid recovery was not essential.
Abstract: Lorazepam has been studied as preanaesthetic medication given by mouth, i.m. and i.v. Sedation and side-effects and the incidence of anterograde amnesia in patients having a standard operation under methohexitone-nitrous oxide-oxygen anaesthesia were assessed. In a preliminary study of three i.m. (2-, 4- and 8-mg) and six oral (1-, 2-, 2.5-, 4-, 5- and 8-mg) doses, the optimum dose was found to be 4 mg for patients with an average weight of 60 kg. This dose was studied in detail when given by all three routes and compared with the commercially available 2.5-and 5-mg tablets. Even when given i.v., there was a delay of 30—40 min in the onset of maximum sedative effect and drowsiness persisted for at least 4 h. Although the onset of action by i.m. injection was slightly faster than when the drug was given by mouth this advantage was more than offset by the high frequencies of pain at the site of injection and restlessness which persisted for 20—40 min. Oral lorazepam in doses of 2.5—5.0 mg was a reliable, effective sedative which could be recommended for routine preanaesthetic medication, provided rapid recovery was not essential. Its soporific effect was accompanied by an appreciable incidence of anterograde amnesia.
TL;DR: Both normal Wistar rat fetuses and those with cleft palate induced by 5-Fluoro-2-Desoxyuridine were studied with a view to elucidating the mechanism of palatal shelf elevation and the pathogenesis of Cleft palate.
Abstract: Both normal Wistar rat fetuses and those with cleft palate induced by 5-Fluoro-2-Desoxyuridine were studied with a view to elucidating the mechanism of palatal shelf elevation and the pathogenesis of cleft palate. It was postulated that normal shelf elevation is brought about rapidly by an intrinsic turgor shelf force generated by binding of water to mucopolysaccharides. Interference with mucopolysaccharide synthesis would seem to be an important factor in the pathogenesis of some types of cleft palate.
TL;DR: Application for these short growth periods early and late in the growing season appeared to be a relatively inefficient use of nitrogen, but nitrate content of herbage did not reach dangerous levels until nitrogen application reached levels beyond those at which maximum dry·matter yield was achieved.
Abstract: A small-plot experiment was made to assess the influence on dry-matter output from grass of a wide range of fertilizer nitrogen and defoliation interval treatments. There were five defoliation treatments, 22, 28, 45, 75 and 112-day regrowth intervalsroughout the growing season each at six levels of nitrogen application, ranging by 300 kg increments from 0 to 1500 kg/ha/year.There was a marked interaction effect between treatments; a positive dry-matter response was maintained to a higher level of applied nitrogen with more frequent defoliation. In 2 years out of 3 maximum dry-matter yield was produced under a 75·day defoliation interval although the mean yield advantage over a 45-day defoliation system was only 11%. Mean yield of digestible dry matter appeared to reach a maximum under a 45·day defoliation interval at 600 kg N/ha but at the lower levels of N the maximum yield was reached at the longest growth interval.Seasonal response to nitrogen under the 22–day and 28–day defoliation systems measured as the increase in yield resulting from increased N at each cutting date reached its peak in July–August. Application for these short growth periods early and late in the growing season appeared to be a relatively inefficient use of nitrogen.The less frequently the sward was harvested and the higher the nitrogen application the greater was the reduction in ground cover as estimated by eye at the end of the growing season, this reached an estimated 25% reduction under 112·day defoliation at 300 kg N/ha/year.In relation to published figures nitrate content of herbage did not reach dangerous levels until nitrogen application reached levels beyond those at which maximum dry·matter yield was achieved.
TL;DR: In this article, the authors measured vertical velocity profiles over various bed configurations (plane beds, ripples, and dunes) in the meandering River South Esk, Glen Clova, Scotland and calculated the lowermost parts of the profiles using the Karman-Prandtl law of the wall.
Abstract: Vertical velocity profiles measured over various bed configurations (plane beds, ripples, and dunes) in. the meandering River South Esk, Glen Clova, Scotland are presented on semilogarithmic paper. Local bed shear stress and roughness height are calculated from the lowermost parts of the profiles using the Karman-Prandtl law of the wall; these parameters, and the geometrical properties of the profiles, are related to the various bed configurations. A graphical model is used to identify profiles developed on specific regions of dune geometry, in order to discriminate those profiles that define bed shear effective in transporting sediment over dunes. An assessment is made of the errors involved in estimating local mean velocity from extrapolating the law of the wall to the water surface. A Darcy-Weisbach friction coefficient is related to bed configuration and local stream power.
TL;DR: Diazepam and flunitrazepam were compared in equipotent doses as induction agents for premedicated patients having cardiac surgery and there was no significant difference between the two drugs in onset time of anaesthesia, cardiovascular or respiratory depression, or quality of induction.
Abstract: Diazepam and flunitrazepam were compared in equipotent doses as induction agents for premedicated patients having cardiac surgery Both drugs caused a significant fall in arterial blood pressure, a rise in Paco2 and a fall in Pao2 There was no significant difference between the two drugs in onset time of anaesthesia, cardiovascular or respiratory depression, or quality of induction There was also no significant difference from induction with thiopentone in these respects Diazepam, over a 02 to 06 mg/kg range of doses showed no difference in toxicity, although induction was clinically smoother with the higher dose
TL;DR: The concentration of BHC residues in the water of rivers discharging into Lough Neagh shows a high correlation with urban population density in the catchment area of the rivers.
TL;DR: A survey of the theory and methods of measurement and their trend towards the perfect scattering experiment can be found in this article, where a detailed coverage is given of various theoretical models and the results compared with experimental data.