Showing papers by "University of Hertfordshire published in 1980"
TL;DR: It is concluded that both μ‐ and κ‐opiate receptors mediate antinociception in animals and that the interactions of analgesic drugs with these receptors may be classified in terms of their antinOCiceptive activities against qualitatively different nociceptive stimuli.
Abstract: 1 To investigate the opiate receptors that mediate antinociception, the activity profiles of opioid analgesic drugs have been determined against different nociceptive stimuli in the mouse and rat. 2 In tests that employ heat as the nociceptive stimulus, mu-opiate receptor agonists, such as morphine, pethidine and dextropropoxyphene, had steep and parallel dose-response curves and were capable of achieving maximum effects. In addition, the antinociceptive potency ratios of these drugs in heat tests were similar to those for analgesia in man. 3 The kappa-agonists, such as ethylketazocine, nalorphine, Mr2034 and pentazocine, were essentially inactive against heat nociception except at doses that caused sedation and motor incapacitation. 4 In the writhing and paw pressure tests both mu- and kappa-agonists produced steep and parallel dose-response curves. 5 It is concluded that both mu- and kappa-opiate receptors mediate antinociception in animals and that the interactions of analgesic drugs with these receptors may be classified in terms of their antinociceptive activities against qualitatively different nociceptive stimuli.
335 citations
TL;DR: In this article, specific hypotheses about particular subgroups within organizations are advanced, which predict variations in the proportions of adaptors and innovators within given organizational structures, and the variations are derived from the adaptor/innovator means of managers in: (a) different departments of a company; (b) different companies; and (c) different management courses.
Abstract: It is theoretically safe to expect that collective decision-making at the managerial level, in most organizations, will be adaptor-dominated to ensure, e.g., stability and continuity; however, the organizations themselves need not necessarily be adaptor-weighted, i.e., contain more adaptors than innovators. Specific hypotheses about particular subgroups within organizations are advanced, which predict variations in the proportions of adaptors and innovators within given organizational structures. Studies are presented supporting these hypotheses. The variations examined are derived from the adaptor/innovator means of managers in: (a) different departments of a company; (b) different companies; and (c) different management courses. These variations suggest that there may even be differences between the means of practitioners of particular occupations.
216 citations
TL;DR: The distribution of cells in a planar section of a soap foam is determined at different stages of growth, and the shape of their sections is related quantitatively to that of the adjoining cell sections by an empirical equation.
177 citations
TL;DR: The results are consistent with the hypothesis that there are two types of receptor mediating 5‐HT‐induced vasoconstriction in dog vasculature, and one of these is like the previously described ‘D‐receptor’.
Abstract: 1 As part of an investigation into the mode of action of anti-migraine drugs, a study of the excitatory receptors for 5-hydroxytryptamine (5-HT) has been carried out in a range of isolated vascular preparations from the dog.
2 5-HT contracted the dog isolated femoral artery and saphenous vein over the concentration-range 1.0 × 10-8 to 5.0 × 10-6 mol/l.
3 In the femoral artery methysergide and cyproheptadine were potent, competitive and specific antagonists of the contractile responses to 5-HT, with pA2 values of 8.52 and 8.55 respectively.
4 In the saphenous vein, methysergide was only a weak antagonist of 5-HT. In addition, it was an agonist over the concentration-range 5.0 × 10-8 to 1.0 × 10-5 mol/l. Cyproheptadine was a weak and unsurmountable antagonist of contractile responses to 5-HT and methysergide.
5 Contractile responses to 5-HT and methysergide in the saphenous vein were not antagonized by morphine (3.0 × 10-5 mol/l), indomethacin (5.0 × 10-5 mol/l), phentolamine (5.0 × 10-7 mol/l), propranolol (1.0 × 10-6 mol/l), atropine (1.0 × 10-6 mol/l), mepyramine (1.0 × 10-6 mol/l) or cimetidine (1.0 × 10-5 mol/l).
6 In the external carotid and lingual arteries the pattern of activity obtained with methysergide and cyproheptadine was the same as that in the femoral artery, while in the auricular artery the pattern of activity was the same as that in the saphenous vein.
7 The results are consistent with the hypothesis that there are two types of receptor mediating 5-HT-induced vasoconstriction in dog vasculature. One type, characterized by the pattern of activity obtained in the femoral artery, is like the previously described `D-receptor'. The other type, characterized by the pattern of activity obtained in the saphenous vein, has not been described before. The verification of this hypothesis requires the identification of a specific antagonist of 5-HT and methysergide in the saphenous vein.
141 citations
TL;DR: In this article, a quasi-steady approach is used to explain the growth of fires in enclosures. But the authors do not consider the effect of thermal radiative feedback from the enclosure.
116 citations
TL;DR: Data obtained with antagonists indicate a consistently higher affinity for the receptor than observed for the β2‐subtype in other tissues but do not suggest a novel β‐adrenoceptor subtype on the mast cell of the human lung.
Abstract: 1 The rank order of potency of six beta-adrenoceptor agonists as inhibitors of the anaphylactic release of histamine from fragments of passively sensitized human lung in vitro was (--)-isoprenaline greater than (--) -adrenaline greater than (+/-)-salbutamol greater than (--)-noradrenaline greater than R0363 greater than H133/22. 2 The beta-adrenoceptor antagonists, propranolol, atenolol and H35/25, blocked the response to both (--)-isoprenaline and (+/-)-salbutamol competitively. Each antagonist gave similar pA2 values with both agonists. pA2 values were consistently at the high end of the range expected for interaction at a beta 2-adrenoceptor. 3 Practolol did not antagonize isoprenaline in a competitive manner but was a competitive antagonist of salbutamol with a pA2 at the high end of the range expected for interaction at a beta 2-adrenoceptor. 4 Data obtained with agonists are consistent with the receptor being of the beta 2-subtype. Data obtained with antagonists indicate a consistently higher affinity for the receptor than observed for the beta 2-subtype in other tissues but do not suggest a novel beta-adrenoceptor subtype on the mast cell of the human lung.
85 citations
TL;DR: The development of systems of chromosomal gene transfer and mapping in Rhizobium, the recent studies implicating indigenous plasmids as important determinants of symbiotic functions and the use of RhizOBium mutants as aids in the biochemical analysis of the symbiosis are considered.
Abstract: In the last few years there has been an increasing interest in the genetics and molecular biology of Rhizobium, the bacterium that is responsible for inducing nitrogen-fixing nodules on the roots of leguminous plants, and in this paper we have reviewed recent work in this field. We have considered, in turn, the development of systems of chromosomal gene transfer and mapping in Rhizobium, the recent studies implicating indigenous plasmids as important determinants of symbiotic functions and, finally, the use of Rhizobium mutants as aids in the biochemical analysis of the symbiosis.
72 citations
TL;DR: Esterase patterns produced from resistant populations by poly-acrylamide gel and starch gel electrophoresis and by isoelectric focusing consistently differed in both numbers of bands and migration rates from the susceptible type.
Abstract: SUMMARY
The resistance to pirimicarb of populations of Aphis gossypii Glover from several glasshouses in England was studied in the laboratory by topical applications of insecticide and by electrophoresis and isoelectric focusing of aphid esterases. When compared with a known susceptible population, the aphids were found to be resistant to pirimicarb. Esterase patterns produced from resistant populations by poly-acrylamide gel and starch gel electrophoresis and by isoelectric focusing consistently differed in both numbers of bands and migration rates from the susceptible type. Resistant A. gossypii were found infesting only chrysanthemums and would not transfer to cucumber, the host of the susceptible population.
63 citations
TL;DR: The sequences of compounds, leading from the natural pyrethrins to the present established pyrethroids, are described so as to provide a background for considering the more recent advances discussed in succeeding papers.
Abstract: The sequences of compounds, leading from the natural pyrethrins to the present established pyrethroids, are described so as to provide a background for considering the more recent advances discussed in succeeding papers.
58 citations
TL;DR: The results suggest that the pressor responses to M-7 are mediated via postsynaptic alpha 2-adrenoceptors.
56 citations
01 Nov 1980
TL;DR: In this paper, the role of enthalpic and entropic forces during exchange is discussed, emphasizing the differences between each “standard” mineral and also the anomalous behavior of the kaolinite and montmorillonite minerals.
Abstract: Differential and integral thermodynamic functions were evaluated from equilibrium isotherm and microcalorimetric measurements for KCa exchange in the <2-μm particles of 1:1 and 2:1 layer aluminosilicates. The heterogeneity of exchange sites for K sorption in each mineral was inferred qualitatively from changes, with K saturation, of the activity coefficient of adsorbed K+ and of the integral functions. However, the corresponding change in differential enthalpy, measured by microcalorimetry, was found to separate precisely groups of sites with constant exchange enthalpies in each mineral. The role of the enthalpic and entropic forces during exchange is discussed, emphasizing the differences between each “standard” mineral, and also the anomalous behavior of the kaolinite and montmorillonite minerals.
TL;DR: X-ray photoelectron spectroscopy (XPS) has been used to study the chemical modification of low density polyethylene and polypropylene using a very mild treatment with chromic-sulphuric acid or treatment with concentrated sulphuric acids.
Abstract: X-ray photoelectron spectroscopy (XPS) has been used to study the chemical modification of low density polyethylene, high density polyethylene and polypropylene using a very mild treatment with chromic-sulphuric acid or treatment with concentrated sulphuric acid. The treatment of low density polyethylene with CrO3-water has been studied in detail by XPS and multiple internal reflection infrared spectroscopy. In all cases surface modification has been correlated with adhesion level to an epoxide adhesive. The XPS data are also used to discuss the adhesion of metals to CrO3-water etched polymers and the effect of surface contaminants on adhesion to epoxides.
TL;DR: The reaction of ethene with deuterium has been catalyzed at 20 °C by platinum supported on titania, magnesia, alumina, silica, and silica-alumina.
TL;DR: Maintaining an internal temperature below 10 degrees C during the boning operation would be sufficient to safeguard public health requirements and criteria for deciding safe handling temperatures for meat are discussed.
Abstract: Growth rates of a mixture of Salmonella serotypes inoculated on beef from a commercial abattoir were measured at chill temperatures. The minimum recorded mean generation times were 8.1 h at 10 degrees C; 5.2 h at 12.5 degrees C and 2.9 h at 15 degrees C. Growth did not occur at 7-8 degrees C. From these data the maximum extent of growth of Salmonella during storage of meat for different times at chill temperatures was calculated. Criteria for deciding safe handling temperatures for meat are discussed. Maintaining an internal temperature below 10 degrees C during the boning operation would be sufficient to safeguard public health requirements.
TL;DR: The antinociceptive activities of morphine, codeine and dextropropoxyphene (μ‐agonists), buprenorphine and Mr 2034 have been determined against nocICEptive responses to electrical stimulation of the tooth pulp in the conscious dog.
Abstract: 1 The antinociceptive activities of morphine, codeine and dextropropoxyphene (micro-agonists), buprenorphine and Mr 2034 [(-)5,9-dimethyl-2-(tetrahydrofurfuryl)-2'-hydroxy-6,7-benzomorphan](k-agonists ) have been determined against nociceptive responses to electrical stimulation of the tooth pulp in the conscious dog. 2 Dose-dependent increases in nociceptive threshold were obtained for all of the analgesic drugs tested at doses within their antinociceptive range as determined in nociceptive pressure and chemical tests in rodents.
TL;DR: The results support the existence of adenosine receptors in the guinea‐pig trachea and caffeine and theophylline enhanced the non‐adrenergic inhibitory response to nerve stimulation (NAIR).
Abstract: 1 To test the possibility that adenosine receptors exist within the trachea of the guinea-pig, an attempt has been made to identify a compound with adenosine antagonist activity in this tissue.
2 Quinidine, phentolamine, phenoxybenzamine, 2-2′-pyridylisatogen tosylate (PIT) and caffeine were tested for antagonism of spasmolytic responses to adenosine, adenosine 5′-triphosphate (ATP) and adenine on the guinea-pig isolated trachea.
3 Quinidine (10 and 25 μg/ml), phentolamine (10 and 30 μg/ml) and phenoxybenzamine (10 μg/ml) had little or no effect on response to adenosine, ATP and adenine. PIT (21 μg/ml) potentiated responses to adenosine, ATP and adenine by an unexplained mechanism.
4 Caffeine (25 μg/ml) partially relaxed the trachea and inhibited spasmolytic responses to both adenosine and ATP, but not to adenine, isoprenaline, aminophylline or prostaglandin E2 (PGE2).
5 A number of compounds related to caffeine (xanthine, hypoxanthine, theophylline and theobromine) were tested for adenosine antagonist activity. Xanthine (300 μg/ml) and hypoxanthine (300 μg/ml) did not relax the trachea or antagonize spasmolytic responses to adenosine. Both theophylline (10 μg/ml) and theobromine (30 μg/ml) partially relaxed the trachea; theophylline, but not theobromine, antagonized spasmolytic responses to adenosine.
6 pA2 values for caffeine and theophylline as antagonists of adenosine were 4.3 and 4.7 respectively. However, the slopes of the Schild plot regressions were significantly less than 1.0 for both compounds.
7 Four compounds, adenine, AH 8883, M30966 and ICI 63197, which like caffeine and theophylline, have phosphodiesterase inhibitory activity were tested for adenosine antagonist activity in the trachea. Adenine and AH 8883 had no effect and M30966 and ICI 63197 caused significant potentiation.
8 The effects of caffeine and theophylline were also investigated on the non-adrenergic inhibitory response to nerve stimulation (NAIR). Both caffeine (100 μg/ml, n = 4) and theophylline (30 μg/ml, n = 4) enhanced the NAIR (20 Hz) while virtually abolishing matched responses to exogenous adenosine.
9 The results support the existence of adenosine receptors in the guinea-pig trachea.
TL;DR: Aerial migrations of Metopolophium dirhodum over Europe in 1979 measured by suction traps indicated that alates flew first in the south of France where the warm climate probably encouraged early population increase.
Abstract: SUMMARY
Aerial migrations of Metopolophium dirhodum over Europe in 1979 measured by suction traps at a height of 12.2 m indicated that alates flew first in the south of France where the warm climate probably encouraged early population increase. Subsequent spread across Europe was gradual and northerly, with the largest populations occurring in East Anglia in late July. The date of the population peak at each site was correlated with latitude, being later at northerly sites, and probably also with crop development.
TL;DR: Carbonic anhydrase should always be included in reaction mixtures used to determine the Michaelis constant of ribulose bisphosphate carboxylase for C02 where fixation of radioactive C02 into phosphoglycerate is the basis of rate estimation.
Abstract: At concentrations of C02 less than saturating, carbonic anhydrase (EC 4.2.1.1) stimulates the carboxylation of ribulose bisphosphate catalysed by ribulose bisphosphate carboxylase (EC 4.1.1.3.9) in vitro. This is not through any beneficial association of the two enzymes but is a consequence of the increased rate of conversion of HCOj ion to C02, the substrate for the carboxylation. Carbonic anhydrase should always be included in reaction mixtures used to determine the Michaelis constant of ribulose bisphosphate carboxylase for C02 where fixation of radioactive C02 into phosphoglycerate is the basis of rate estimation. The effect is to decrease the value obtained for the Michaelis constant.
TL;DR: In this article, a new design for a rotor system to achieve spinning rates of the order of 3 kHz is presented, which uses a simple cylindrical rotor, and involves a forced air bearing over the whole cylinrical surface.
TL;DR: In this paper, oil-seed rape and beekeeping, particularly in Britain, are discussed. But the focus is on the oil-seed rape and not the beekeeping process.
Abstract: (1980). Oil-Seed Rape and Beekeeping, Particularly in Britain. Bee World: Vol. 61, No. 4, pp. 141-153.
TL;DR: On potted seedlings exposed within a crop most infection occurred during long rain periods or when rain fell late in the evening; fewest lesions usually developed on seedlings prevented from touching adjacent plants.
Abstract: SUMMARY
The numbers of spores of Rhynchosporium secalis washed from samples of barley plants taken weekly, varied markedly. No consistent association with amount of previous rainfall or length of the preceding dry period was detected. On potted seedlings exposed within a crop most infection occurred during long rain periods or when rain fell late in the evening; fewest lesions usually developed on seedlings prevented from touching adjacent plants.
Rotorod traps fitted with a 13 mm diameter disc at the apex of each arm were operated under 24 cm diameter covers. Spores were collected on circular cover slips fixed to each disc with glycerine jelly. At all stages of crop growth more spores were trapped at ground level than at other heights tested up to 1 m. The number of spores trapped was not related to the quantity of or duration of rainfall but was related to the mean rate of fall during brief showers only. Efficiency of droplet retention was assessed in a wind tunnel. It declined rapidly when more than c. 5 pl was presented to the disc surface and was less at a wind speed of 1.0 than 0.5 m s-l. Spore distribution on discs indicated that spores were washed from the surface during long rain periods.
TL;DR: Immunofluorescence appeared to be more sensitive but less reliable than conventional plating methods for fireblight diagnosis and differential centrifugation greatly improved the rate of detection of E. amylovora in plant tissue.
Abstract: SUMMARY
An immunofiuorescent (fluorescent antibody or FA) staining technique was used to detect Erwinia amylovora (Burrill) Winslow et al. in plant tissue, but in preliminary trials it failed to do so in a majority of preparations from fireblight-infected plants. Differential centrifugation greatly improved the rate of detection of E. amylovora in plant tissue. Ctiltures of E. herbicola subsp. ananas (Serrano) Dye, E. stewartii (Smith) Dye, E. rhapontici (Millard) Burkholder and two plant isolates (probably Pseudomonas fiuorescens (Trevisan) Migula and E. herbicola subsp. herbicola (Lohnis) Dye) cross-reacted with E. amylovora in the FA stain. Of these only the Ps. fiuorescens isolate and a different plant isolate of E.h. subsp. herbicola cross-reacted with E. amylovora anti-serum in the slide agglutination test. Use of absorbed E. amylovora antiserum completely eliminated cross reactions in the slide agglutination test, but only partly removed cross reactions in the FA stain. Immunofluorescence appeared to be more sensitive but less reliable than conventional plating methods for fireblight diagnosis.
TL;DR: Large populations of bees often continue to forage on oil-seed rape crops until flowering ceases, and applications of insecticide to crops in the late flowering stage could be hazardous to these bees.
Abstract: Large populations of bees often continue to forage on oil-seed rape crops until flowering ceases. Applications of insecticide to crops in the late flowering stage could be hazardous to these bees.
TL;DR: In this paper, the authors examine the recent assertion by a scholar of Burmese history that extensive landholding by the Buddhist monkhood helped to undermine every dynasty between the ninth and nineteenth century, and argue that religious wealth, possibly before the fifteenth century and certainly after that period, was less significant than has been suggested, and that the institutional relation between throne and monkhood was by no means static.
Abstract: This article examines the recent assertion by a scholar of Burmese history that extensive landholding by the Buddhist monkhood helped to undermine every dynasty between the ninth and nineteenth century. It argues that religious wealth, possibly before the fifteenth century and certainly after that period, was less significant than has been suggested, and that the institutional relation between throne and monkhood was by no means static. During the later dynasties, secular elites represented the principal threat to the centralization of resources. Further, in certain instances, royal purification of the Religion sought not to deprive the monkhood of wealth, but to strengthen both the Religion and the crown at the expense of private lay interests.
TL;DR: In this paper, the potato cyst-nematode Globodera rostochiensis was controlled in peaty loam by growing the resistant potato cultivars Cara and Maris Piper, or incorporating aldicarb or oxamyl granules in the seed bed before planting susceptible cultivars.
Abstract: Potato cyst-nematode, Globodera rostochiensis, was controlled in peaty loam by growing the resistant potato cultivars Cara and Maris Piper, or by incorporating aldicarb or oxamyl granules in the seed bed before planting susceptible cultivars. In heavily infested soils, aldicarb or oxamyl increased tuber yields of susceptible cultivars and Maris Piper but did not increase tuber yields of Cara, which suggests that it is tolerant as well as resistant. Yield responses to oxamyl varied greatly among susceptible cultivars. In the top 20 cm of untreated soil, the nematodes increased twice as much on Bang Edward as on five other susceptible cultivars.
Patent•
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TL;DR: A touch switch device includes a touch plate 3 or other touch member arranged, when touched, to interrupt the passage of an oscillating signal from a DC powered oscillator 31-34 to a charging circuit 36-39, including a capacitative store 38 as discussed by the authors.
Abstract: A touch switch device includes a touch plate 3 or other touch member arranged, when touched, to interrupt the passage of an oscillating signal from a DC powered oscillator 31-34 to a charging circuit 36-39, including a capacitative store 38 The charging circuit responds to this interruption to initiate discharge of the charge store, and a control, including an inverter 44 and a flip-flop 46 controls a switch 48 to change from one state to another upon a change of charge state, in this case a recharge, of the charge store A circuit 51-54 supplies a reset signal to the flip-flop during an initial preset period immediately following the switching on of power to the device, to inhibit this change of state of the switch 48 during such period
TL;DR: Serological tests were made using a simple kit consisting of dropper bottles filled with latex sera or buffer, a plastic mixing plate, plastic pipettes, wooden cocktail sticks and polythene bags, packed in a plastic sandwich box.
Abstract: SUMMARY
Serological tests were made using a simple kit consisting of dropper bottles filled with latex sera or buffer, a plastic mixing plate, plastic pipettes, wooden cocktail sticks, a black glass reaction plate and polythene bags, packed in a plastic sandwich box. Potato viruses X, S and Y were readily detected in infected potato leaves in tests done both in the laboratory and in the field. Results were obtained in 4–10 min.
TL;DR: It is tentatively suggested on the evidence of symbiotic performance that R. japonicum is a specialised group within R. spp.
Abstract: SUMMARY
Strains of Rhizobium spp. (cowpea miscellany) and R. japonicum are characterised by their symbiotic performance on two hosts, Vigna unguiculata cv. Ife Brown and Glycine rnax cv. Bossier. The results indicate that isolates from G. max cv. Malayan, a promiscuously nodulating cultivar adapted to Nigerian conditions, form a group intermediate between R. japonicum and R. spp. but are more closely related to the latter. We tentatively suggest on the evidence of symbiotic performance that R. japonicum is a specialised group within R. spp.