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Showing papers by "University of Hertfordshire published in 1978"


Journal ArticleDOI
02 Mar 1978-Nature
TL;DR: Certain phosphonopeptides, of which L-alanyl-‘L’-l-aminoethylphosphonic acid (alaphosphin) is typical, inhibit the growth of various important pathogenic bacteria in vitro and in infected animals.
Abstract: ANTIBIOTICS of the group that includes the penicillins, the cephalosporins, D-cycloserine and vancomycin, act by interfering with the biosynthesis of bacterial cell walls1,2. This is achieved by inhibiting the formation, or the subsequent utilisation in cross-linking, of the terminal D-Ala-D-Ala units which occur in the peptide chains of the cell-wall peptidoglycans of all pathogenic bacteria so far investigated3–5. We have sought new synthetic compounds, related to D-Ala-D-Ala, that have similar antibacterial action. We report here that certain phosphonopeptides, of which L-alanyl-‘L’-l-aminoethylphosphonic acid (alaphosphin) is typical, inhibit the growth of various important pathogenic bacteria in vitro and in infected animals.

383 citations


Journal ArticleDOI
TL;DR: The results demonstrate that the presynaptic α‐adrenoceptors in the guinea‐pig ileum are of the same type as those located presynaptically in sympathetically innervated tissues.
Abstract: 1 The presynaptic alpha-adrenoceptors located on the terminals of the cholinergic nerves of the guineapig myenteric plexus have been characterized according to their sensitivities to alpha-adrenoceptor agonists and antagonists.2 Electrical stimulation of the cholinergic nerves supplying the longitudinal muscle of the guinea-pig ileum caused a twitch response. Clonidine caused a concentration-dependent inhibition of the twitch response; the maximum inhibition obtained was 80 to 95% of the twitch response. Oxymetazoline and xylazine were qualitatively similar to clonidine but were about 5 times less potent. Phenylephrine and methoxamine also inhibited the twitch response but were at least 10,000 times less potent than clonidine.3 The twitch-inhibitory effects of clonidine, oxymetazoline and xylazine, but not those of phenylephrine or methoxamine, were reversed by piperoxan (0.3 to 1.0 mug/ml).4 Lysergic acid diethylamide (LSD) inhibited the twitch response, but also increased the basal tone of the ileum. Mepyramine prevented the increase in tone but did not affect the inhibitory action of LSD. Piperoxan or phentolamine only partially antagonized the inhibitory effect of LSD.5 Phentolamine, yohimbine, piperoxan and tolazoline were potent, competitive antagonists of the inhibitory effect of clonidine with pA(2) values of 8.51, 7.78, 7.64 and 6.57 respectively.6 Thymoxamine was a weak antagonist of clonidine; it also antagonized the twitch-inhibitory effect of morphine. Thus, its effect against clonidine is probably not mediated specifically at presynaptic alpha-adrenoceptors.7 Labetalol, itself, depressed the twitch response but did not antagonize the inhibitory effect of clonidine on the residual twitch.8 The results demonstrate that the presynaptic alpha-adrenoceptors in the guinea-pig ileum are of the same type as those located presynaptically in sympathetically innervated tissues. They are alpha(2)-adrenoceptors and are different from those located postsynaptically.

211 citations


Journal ArticleDOI
TL;DR: The infection process in Arachis hypogaea by rhizobia differs from that normally found in Trifolium spp.
Abstract: The infection process in Arachis hypogaea by rhizobia differs from that normally found in Trifolium spp in that no infection threads are formed The root hairs, which are long (up to 4 mm), septate, and often with large basal cells, occur only at the sites of emerging lateral roots Infection occurs only where the root hairs have large basal cells Rhizobia cause curling and deformation of the root hairs (as in Trifolium spp) but enter the root at the junction of the root hair and the epidermal and cortical cells The bacteria are distributed intercellularly via the middle lamellae and enter the cortical cells through the structurally altered cell wall, often close to the host cell nucleus The root hairs and large basal cells become infected in the same way Within the cortical cells of the emerging lateral root the rhizobia multiply rapidly and the invaded cells divide repeatedly to form the nodule tissue Bacteriod formation occurs only when the host cell ceases to divide

177 citations


Journal ArticleDOI
TL;DR: In this article, a chain of good chips are automatically bypassed without requiring any pre- or post-programming of the metallization and without any prior knowledge of the distribution of faulty chips on the wafer.
Abstract: Considers a new approach to full-slice technology in relation to existing procedures for achieving this goal. Under external control a chain of good chips is created to form a long serial memory from an array of identical chips on a full slice. Bad chips are automatically bypassed without requiring any pre- or post-programming of the metallization and without any prior knowledge of the distribution of faulty chips on the wafer. Computer simulations of chain formation are described which demonstrate the feasibility of creating such serial memories at practicable dice-yield levels. The proposed logic design is summarized and its verification by TTL simulation is noted. The inherent fault and failure tolerance of the design are discussed and the potential problem areas of short-circuit chips, double-level metallization, spiral branching, thermal dissipation, and noise/pattern sensitivity are described together with suggested solutions.

125 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of drought on the harvest yield and its components, on water use and nutrient uptake, was investigated, and it was shown that a prolonged early drought had an exceptionally large effect on both yield and water use.
Abstract: Automatic mobile shelters were used to keep rain off a barley crop in a drought experiment. The treatments ranged from no water during the growing season to regular weekly irrigation. This paper reports the effect of drought on the harvest yield and its components, on water use and nutrient uptake.Drought caused large decreases in yield, and affected each component of the grain yield. The magnitude of each component varied by up to 25% between treatments, and much of the variation could be accounted for by linear regression against the mean soil water deficit in one of three periods. For the number of grains per ear, the relevant period included tillering and ear formation; for the number of ears per unit ground area, the period included stem extension and tiller death; for grain mass, the period included grain filling.The harvest yields were linearly related to water use, with no indication of a critical period of drought sensitivity. The relation of grain yield to the maximum potential soil water deficit did show that a prolonged early drought had an exceptionally large effect on both yield and water use.Two unsheltered irrigation experiments, also on barley, were made in the same year on a nearby site. The effects of drought on yield in these experiments were in good agreement with the effects observed on the mobile shelter site.When fully irrigated, the small plots under the mobile shelters used water 11% faster than larger areas of crop, because of advection. The maximum depth from which water was extracted was unaffected by the drought treatment. When 50% of the available soil water had been used the uptake rate decreased, but the maximum depth of uptake continued to increase.Measurements of crop nutrients at harvest showed that nitrogen uptake was large, because of site history, and that phosphate uptake was decreased by drought to such an extent that phosphate shortage may have limited yield.

122 citations


Journal ArticleDOI
TL;DR: The tissue distribution of the enzymes of intermediary metabolism must be known before they are used as diagnostic aids in a particular species, and how the plasma activities of these enzymes alter in that species after experimental lesions have been induced is needed.

101 citations


Journal ArticleDOI
TL;DR: During the early period of infestation of winter rape, pollen beetles and seed weevils were mainly feeding and attaining sexual maturity, with some loss of seed weight and viability when feeding on pods of spring rape.
Abstract: During the early period of infestation of winter rape, pollen beetles and seed weevils were mainly feeding and attaining sexual maturity. Before a crop flowered pollen beetles fed on buds but only some of those which they had perforated to obtain pollen dropped off. When flowering started adults obtained pollen from flowers rather than from buds. They laid their eggs in the buds but not in the flowers. Larvae moved from flower to flower up the raceme and caused no damage. Probably many podless stalks have been wrongly attributed to pollen beetle damage.Overwintered seed weevils caused no damage by feeding on rape pods. New generation seed weevils caused some loss of seed weight and viability when feeding on pods of spring rape; this is probably unimportant on a field scale.Pollen beetles and seed weevils mated from mid-May until the emergence of new generation adults; these did not mate before hibernating.

89 citations


Journal ArticleDOI
TL;DR: When most of the grains were removed from wheat ears the remaining grains developed increased numbers of aleurone and endosperm cells, and the increased grain volume was accompanied by an enlargedendosperm cavity.
Abstract: When most of the grains were removed from wheat ears the remaining grains developed increased numbers of aleurone and endosperm cells, and the increased grain volume was accompanied by an enlarged endosperm cavity. The giant grains usually synthesized starch more rapidly than normal grains. Flag leaf photosynthesis was unaffected and additional sugar was retained in the culm and glumes. Total nitrogen and free amino acid content increased. Gibberellin and auxin concentrations were greater in the glumes of the partly degrained ears, and auxin in the grains was also greater than in equivalent grains from intact ears.

72 citations


Journal ArticleDOI
TL;DR: The protein-glycogen particle preparation isolated from rabbit skeletal muscle extracts by mild acidification and differential centrifugation shows eight major protein-staining bands when examined by polyacrylamide gel electrophoresis, five of which have previously been identified as the glycogen debranching enzyme, the α and β subunits of phosphorylase kinase, glycogen phosphoryLase and glycogen synthase.
Abstract: The protein-glycogen particle preparation isolated from rabbit skeletal muscle extracts by mild acidification and differential centrifugation shows eight major protein-staining bands when examined by polyacrylamide gel electrophoresis, five of which have previously been identified as the glycogen debranching enzyme, the α and β subunits of phosphorylase kinase, glycogen phosphorylase and glycogen synthase [Taylor, C., Cox, A. J., Kernohan, J. C. & Cohen, P. (1975) Eur. J. Biochem. 51, 105–115]. The other three major proteins in this preparation have now been identified. Two of the proteins were identified as the heavy chain of myosin and actin respectively, based on their electrophoretic migration, their insolubility in buffers of low ionic strength, and their solubility in buffers containing 0.6 M KCl. The third protein has been found to be calsequestrin, a major calcium-binding protein of the sarcoplasmic reticulum. This conclusion was based on the unusual chromatographic behaviour of the protein on DEAE-cellulose at pH 7.5, its electrophoretic mobility, amino acid composition, and immunological cross reactivity. A simple method for the isolation of calsequestrin as a by-product of the purification of glycogen synthase has been developed, by which 70–80 mg of the protein were routinely isolated from 5000 g of muscle (6 rabbits) within five days. The protein was homogeneous by the criterion of polyacrylamide gel electrophoresis and sedimentation equilibrium centrifugation. The molecular weight determined by the latter technique was 41000 and the absorbance index A280 nm1%, was 11.7. The protein had a very low sedimentation coefficient of 1.97 S indicating that it is either very asymmetric or a largely unfolded protein, in the buffers used in these experiments, a conclusion supported by its abnormal gel filtration behaviour. Since the three hitherto unidentified components of the protein-glycogen particle preparation are not enzymes of glycogen metabolism and merely constituents of particulate material (actomyosin and fragments of the sarcoplasmic reticulum) which have coprecipitated with the protein-glycogen complex, over 95% of the protein attached to glycogen is accounted for by just four enzymes.

70 citations


Journal ArticleDOI
TL;DR: The dip-test, a simple, rapid and inexpensive bioassay designed to detect resistance and its different levels gave satisfactory results which warrant its use where biochemical detection of resistance is not possible.
Abstract: Examination of the enzyme that determines the level of resistance to organophosphorus insecticides and carbamates in Myzus persicae (Sulz.) and bioassays were used to establish the frequency and resistance levels of resistant aphids on outdoor crops in Britain in 1976. The biochemical tests, staining esterase-4 after electrophoresis and total esterase determination, were more sensitive than bioassays. However the dip-test, a simple, rapid and inexpensive bioassay designed to detect resistance and its different levels gave satisfactory results which warrant its use where biochemical detection of resistance is not possible. Carboxylesterase activities of M. persicae collected in 1976 fell into three groups: low, moderate and high, and these were correlated with differences in tolerance to dimethoate, demeton-S-methyl and pirimicarb. Aphids with low esterase activity were susceptible(S). Those with the moderately active enzyme (R1) had five- to seven-fold resistance to the two organophosphorus insecticides and were marginally resistant (about two-fold) to pirimicarb. The insects with the most active esterase (R2) were strongly resistant to dimethoate (resistance factor, RF × 126) and moderately resistant to demeton-S-methyl (RF × 17) and pirimicarb (RF × 8). Some R1, but no S aphids survived the recommended dose of demeton-S-methyl on field crops probably because they were under the lowest leaves and therefore protected from direct contact with the spray. Laboratory tests demonstrated that these R1 aphids tolerated the residual deposit and systemic dose present in the leaves of the treated potato-plants. This enabled their numbers to recover in treated fields much faster than the susceptible insects which could do so by immigration only when the residual dose in the plant was no longer toxic. R1 aphids were common throughout the country particularly in eastern England where susceptible aphids were rare, but in the Shardlow area of Derbyshire susceptible aphids were in the majority throughout the summer. R2 aphids were found only in samples from the west of Scotland and northern England. The implications of the presence of aphids with different levels of resistance for aphid control are discussed.

67 citations


Journal ArticleDOI
TL;DR: Inadequate pollination probably limits yield in self-fertile cultivars of swede rape that auto-pollinate poorly and in turnip rape cultivars that are nearly self-sterile.
Abstract: The pollination requirements of eight cultivars of swede rape (Brassica napus) and two of turnip rape (Brassica campestris) grown in a glasshouse, were compared Cultivars differed in the number of pods, and of seeds per pod set by auto-pollination Cultivars of turnip rape yielded more when cross-pollinated than when self-pollinated by hand but those of swede rape did not, although additional pollination of swede rape increased the set of early flowers Inadequate pollination probably limits yield in self-fertile cultivars of swede rape that auto-pollinate poorly and in turnip rape cultivars that are nearly self-sterile

Journal ArticleDOI
TL;DR: In this paper, RuDP carboxylase protein and activity were determined in relation to net photosynthetic rate during the senescence of intact flag leaves of wheat on the plant.
Abstract: Ribulose-l,5-diphosphate (RuDP) carboxylase protein and activity were determined in relation to net photosynthetic rate during the senescence of intact flag leaves of wheat on the plant. Initially the decrease in RuDP carboxylase activity was greater than the decline in net photosynthesis. The major decrease in RuDP carboxylase activity over this period resulted from a decrease in enzyme specific activity from 11 to 2 ,umol C02 fixed h_1 mg-1 protein. Loss of RuDP carboxylase protein did not occur until late in senescence by which time chlorophyll concentration had decreased by more than 50%. Treatment of flag leaves at weekly intervals with either 1000 parts 10~6 2-chloro ethyltrimethylammonium chloride or 100 parts 10~6 gibberellic acid with 1 part 10~6 kinetin did not significantly affect net photosynthetic rate, RuDP carboxylase protein or activity during senescence.

Journal ArticleDOI
TL;DR: The results obtained on the distribution of nitrogen between the various fractions in the seeds of Bomi and RisO 1508 and on the amino acid analysis and polypeptide composition differ considerably from those published by other workers, in which a classical Osborne type extraction was used as mentioned in this paper.
Abstract: Whole seed of barley (cv. Julia) was ground, and the meal extracted to remove lipids, non-protein nitrogen compounds, albumins, and globulins. Four procedures for extracting hordein and glutelin from this meal were then compared. The composition of the isolated fractions was monitored by amino acid analysis and SDS polyacrylamide gel electrophoresis. More hordein was extracted by 55% (v/v) propan-2-ol containing 2% (v/v) 2-mercaptoethanol at 60 °C than at 20 °C or by sequential extraction with 55% propan-2-ol alone followed by 55% propan-2-ol plus 0.6% 2-mercaptoethanol. After hordein extraction glutelins were successfully extracted from the residual meal by reduction and alkylation in buffer containing 8 M urea, and were precipitated by dialysis against water. Small amounts of hordein were recovered from the alkylated glutelin by washing with hot 70% (v/v) ethanol plus 0.7% (v/v) acetic acid. The acid alcohol-insoluble glutelin was free from hordein polypeptides. Glutelins were also extracted sequentially using borate buffer at pH 10 with 0.6% mercaptoethanol followed by the same buffer with 1% SDS. Two procedures were used to compare the hordein and glutelin composition of endosperms of high lysine (RisO 1508) and normal (Bomi, Julia) barley varieties. The hordein extracted at 60°C by 55% propan-2-ol plus 2% 2-mercaptoethanol represented almost 50% of the total N of the endosperm of Bomi and Julia, and 16% of RisO 1508. The high lysine mutant (RisO 1508) had more glutelin and salt-soluble nitrogen than Bomi. Electrophoretic analysis of the component polypeptides of the hordein of Bomi and RisO 1508 showed several differences in the bands present, and in their relative proportions. In contrast the hordein-free glutelins of all three varieties appeared to have similar polypeptide compositions. Investigation of the salt-soluble fraction confirmed that the high lysine gene in RisO 1508 results in increases in both protein and non-protein nitrogen components. The results obtained on the distribution of nitrogen between the various fractions in the seeds of Bomi and RisO 1508 and on the amino acid analysis and polypeptide composition differ considerably from those published by other workers, in which a classical Osborne type extraction was used, and we conclude that such methods should not be used for barley.

Journal ArticleDOI
TL;DR: The number of insecticide applications to spring rape crops was positively correlated with the number of years for which the farmer had grown rape, and the proportion of pods infested with seed weevil in winter rape plants was not great.
Abstract: No correlation was found between the seed yield per plant of oil-seed rape, the percentage of podless stalks and the percentage of pods infested with seed weevil larvae. The weight per seed and the percentage of podless stalks of winter and spring rape plants were similar.In winter crops the mean number of seeds per plant, weight of seeds per plant, and number of pods per plant were greater near the crop centre than near the crop edge. Plants with relatively few seeds tend to compensate by having heavier ones.Pods infested with seed weevil had fewer and lighter seeds than pods not infested, but the overall decrease in weight of seed per pod was small. The proportion of pods infested with seed weevil in winter rape was twice that in spring rape plants, but was not great. In lightly infested fields the weevils were concentrated at the edges, but the opposite occurred as infestation increased.Infestation of pods of winter rape by seed weevil increased with the number of years rape had been grown on the farm. There was no correlation between insecticide application and yield, but the number of insecticide applications to spring rape crops was positively correlated with the number of years for which the farmer had grown rape.

Journal ArticleDOI
TL;DR: In this article, a semi-insulating epitaxial gallium arsenide can be readily produced, and its use as a buffer layer in MESFET's is demonstrated.


Journal ArticleDOI
TL;DR: The characteristics of the starch in flour appear to be critical in high-ratio cakes and it is suggested that chlorine effects the necessary changes in starch behavior by reacting with the noncarbohydrate surface contaminants on the granules.
Abstract: The literature on the role of chlorine treatment of flour for use in high-ratio cake production is discussed in relation to current knowledge of cereal chemistry and cake technology. A brief perspective of the present use of chlorine in high-ratio cake flours is included. Investigations of the uptake of gaseous chlorine by flour and its distribution among and chemical action upon the major flour components (water, protein, lipid, and carbohydrate) are assessed. The physical effects of chlorination as demonstrated by experiments with batters and cakes and by physicochemical observations of flour and its fractions are also considered. The characteristics of the starch in flour appear to be critical in high-ratio cakes. Chlorine treatment modifies the gelatinization behavior of the starch granules yet does not change their gelatinization temperature not is there evidence of chemical attack upon the starch molecules. Therefore, it is suggested that chlorine effects the necessary changes in starch behavior by reacting with the noncarbohydrate surface contaminants on the granules. Alternative methods of improving high-ratio cake flours are mentioned, particularly heat-treatment processes.

Journal ArticleDOI
TL;DR: The results are consistent with the reduction of nitrite to ammonia involving nitrate-induced nitrite reductase and a reductant generated by the chloroplast electron transport chain.
Abstract: Chloroplasts were prepared from peas ( Pisum sativum ) in glucose-phosphate medium. In the presence of dl-glyceraldehyde, they catalyzed nitrite-dependent O 2 evolution (mean of 13 preparations, 17.5 μmole per mg chlorophyll per hour, sd 3.64). The optimum concentration of nitrite was 0.5 mm; 0.12 mm nitrite supported V max /2. The reaction was accompanied by the consumption of nitrite; 55 to 80% of the nitrite-N consumed was recovered as ammonia. In short experiments (less than 10 minutes) the O 2 to nitrite ratio approached 1.5, but thereafter decreased. There was no nitrite-dependent O 2 evolution with chloroplasts from plants grown without added nitrate but such chloroplasts could assimilate ammonia at about the usual rate. The results are consistent with the reduction of nitrite to ammonia involving nitrate-induced nitrite reductase and a reductant generated by the chloroplast electron transport chain. In the presence of ADP, pyrophosphate, and MgCl 2 the O 2 to nitrite ratio was typically 0.5 to 0.6 and the recovery of nitrite-N as ammonia about 60%. Under these conditions, α-ketoglutarate increased the O 2 to nitrite ratio (0.9-1.35) and the recovery of nitrite-N as ammonia decreased to 27%. These data and the results of nitrite plus ammonia addition experiments (with and without α-ketoglutarate) are attributed to incorporation of nitrite-N into glutamate via the chloroplast enzymes nitrite reductase, glutamine synthetase, and glutamate synthetase.

Journal ArticleDOI
TL;DR: In this paper, the source of these sporadic ozone episodes is shown to be the intrusion of stratospheric air into the lower troposphere, which makes no contribution to ozone exposure levels in urban areas.

Journal ArticleDOI
TL;DR: Results obtained in the laboratory at Rothamsted from 1964 to 1977 on the contact and oral toxicities of 60 pesticides to worker honey bees are summarised.
Abstract: SUMMARY Results obtained in the laboratory at Rothamsted from 1964 to 1977 on the contact and oral toxicities of 60 pesticides to worker honey bees are summarised.

Journal ArticleDOI
TL;DR: The response of susceptible (S), moderatelyresistant (R1) and strongly resistant (R2) peach-potato aphids, Myzus persicae (Sulz.) to organophosphorus, carbamate and pyrethroid insecticides was tested by a leaf-dip bioassay.
Abstract: The response of susceptible (S), moderately resistant (R1) and strongly resistant (R2) peach-potato aphids, Myzus persicae (Sulz.) to organophosphorus, carbamate and pyrethroid insecticides was tested by a leaf-dip bioassay. The aphids were placed on potato leaves (dipped in insecticide solutions 1–2 or 24 h before infestation) and their mortality examined 48 h later. R1 aphids were virtually susceptible to most of the carbamates, demephion and acephate, but were slightly to moderately resistant (2.1–9.4 times) to permethrin, cypermethrin and (S)-α-cyano-3-phenoxybenzyl (1R)-cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylate (I), (NRDC 161), to 5,6,7,8-tetrahydro-2-methylquinolin-4-yl dimethylcarbamate (II), (Hoechst 25 682) and demeton-S-methyl. R2 aphids resisted more strongly or very strongly (between 65 and 1280 times) the pyrethroids, demeton-S-methyl (×94), II (×83) and demephion (×9), and were slightly to moderately (2–5 times) resistant to acephate, pirimicarb, ethiofencarb and 2-(dimethylcarbamoyloxyimino)-3-methoxyimino-N,N- dimethylbutyramide (III), (DPX 3853). Both resistant strains were susceptible to nitrilacarb [4,4-dimethyl-5-(methylcarbamoyloxyimino)pentanenitrile] complex (1:1) with zinc chloride (IV), (AC 85 258). The implications of these results in terms of practical aphid control are discussed.


Journal ArticleDOI
TL;DR: The use of water and chemicals in the textile industry and the volume, nature and composition of process effluents, the effect they have on the environment and the limitations they pose on the reuse of water are discussed in this paper.
Abstract: The paper considers the use of water and chemicals in the textile industry and the volume, nature and composition of process effluents, the effect they have on the environment and the limitations they pose on the reuse of water. An outline is given of the methods available for treatment of waste waters from the industry, on site or at a Water Authority's works and the effects that chemical constituents of the effluents have on the treatment processes and on disposal of water and sludge. The assessment and significance of biodegradability and the extent of present-day knowledge on the biodegradability of the main classes of chemicals used in textile processing are discussed. The paper concludes with a section dealing with the removal of colour from waste waters.

Journal ArticleDOI
TL;DR: It is concluded that in the saphenous vein, low concentrations of 5‐HT act directly on specific 5‐ HT receptors and that high concentrations of5‐HT also act indirectly on α‐adrenoceptors by displacing noradrenaline from neuronal stores.
Abstract: 1 5-Hydroxytryptamine (5-HT) contracted isolated saphenous vein strips of the dog, producing a biphasic concentration-effect curve. The first phase occurred with low concentrations of 5-HT (1.0 X 10(-8) TO 5.0 X 10(-6) mol/l) with a plateau between 1.0 x 10(-6) mol/l and 1.0 x 10(-5) mol/l. The second phase occurred with high concentrations of 5-HT (greater than 1.0 x 10(-5) mol/l). 2 The alpha-adrenoceptor antabonists, phentolamine (5.0 x 10(-8) to 5.0 x 10(-7) mol/l), labetalol (1.0 x 10(-6) to 1.0 x 10(-5) mol/l) and thymoxamine (1.0 x 10(-6) to 1.0 x 10(-5) mol/l), antagonized responses to high concentrations of 5-HT but responses to low concentrations of 5-HT were not antagonized. 3 The effects of high concentrations of 5-HT were antagonized by cocaine (1.0 x 10(-6) to 1.0 x 10(-5) mol/l) and were not evident in veins removed from dogs pretreated with syrosingopine. 5-HT receptors and that high concentrations of 5-HT also act indirectly on alpha-adrenoceptors by displacing noradrenaline from neuronal stores.

Patent
10 Oct 1978
TL;DR: In this article, the bushing was removed from the housing 16 of the steering gear assembly and rotated 180° and then reinserted into the housing to provide an unworn bearing surface which slidably engaged the rack 12.
Abstract: A rack and pinion gear assembly 10 (FIG. 1) includes a resilient bushing which urges the rack into meshing engagement with the pinion. An arcuate inside bearing surface 54 (FIG. 4) of the bushing 18 has a larger radius of curvature than the curved outside surface 52 of the rack 12 against which it bears. The rack thus makes tangent contact with the bushing 18. When one portion of the bushing 18 is worn and therefore excessive play appears in the steering gear assembly 10, the bushing may be removed from the housing 16 of the assembly and rotated 180° and then reinserted into the housing to thereby provide an unworn bearing surface which slidably engages the rack 12. The bushing 18 includes a plurality of axially extending grooves 70, 72, 74, and 76 through which lubricant is supplied to the bearing surfaces 52 and 54. In a second embodiment (FIG. 5) the aperture 50b in the bushing 18b through which the rack 12b extends has a square cross section and is in tangent contact with the rack at two locations 84 and 86. In a third embodiment (FIG. 3) the aperture 50c in the bushing through which the rack 12c extends is composed of four arcuate segments 100, 102, 104, and 106 each having the same radius of curvature, and each having a different center of curvature 110, 112, 114, and 116, respectively. This provides tangent contact between the rack 12c and the bushing 18c at two axially extending areas 120 and 122.


Journal ArticleDOI
TL;DR: A method is described to confirm the presence of 19-nortestosterone metabolites in urine after the administration of veterinary preparations of this anabolic steroid to horses.
Abstract: A method is described to confirm the presence of 19-nortestosterone metabolites in urine after the administration of veterinary preparations of this anabolic steroid to horses. The method is based upon the detection, by gas chromatography mass spectrometry or selected ion monitoring, of an isomer of estrane-3,17-diol in the urine.

Journal ArticleDOI
TL;DR: Turnstones wintering on the seaboard of western Europe breed in Greenland and north-east Canada as discussed by the authors, where they pause to replenish fat reserves, but then continue south to African moulting and wintering grounds.
Abstract: Almost all Turnstones wintering on the seaboard of western Europe breed in Greenland and north-east Canada. Turnstones breeding in northern Europe migrate through the North Sea, where they pause to replenish fat reserves, but then continue south to African moulting and wintering grounds.

Journal ArticleDOI
TL;DR: In this paper, the development of the hypocaust gives an idea of the state of the art at the time of the Roman occupation of Britain, and explains why the importance of baths in the history of architecture, usually taken as being almost axiomatic, is determined by comfort physics.

PatentDOI
TL;DR: In this article, a pair of electrodes are applied externally to the larynx region of the speaker's neck, where one electrode feeds a carrier voltage to the speaker, and the other electrode receives the resultant Larynx amplitude-modulated current.
Abstract: The invention relates to the monitoring, recording and display of a speaker's larynx waveform, for the purposes of education, speech therapy and speech analysis. A pair of electrodes are applied externally to the larynx region of the speaker's neck. Each electrode has two concentric surfaces (the outer surface is called a guard ring). One electrode feeds a carrier voltage to the speaker's neck. The other electrode receives the resultant larynx amplitude-modulated current. Detection techniques are used to derive the larynx waveform. A preferred detection technique is "slicing" which is herein defined as a demodulation which follows the changes in envelope of an amplitude-modulated carrier and retains only the small rapid larynx modulation filtering out the slower neck-movement modulation. The important feature of speech called intonation, which is made up of rhythm and pitch patterns, is directly correlated with larynx frequency. The present larynx waveform provides a simple and reliable basis both for the representation of intonation in speech and for the analysis of the frequencies defining other speech pattern features. Any combination of these patterns is displayed, on a domestic television receiver, for instance, and, or plotted or recorded.