Showing papers by "University College Cork published in 1980"

Artificial substrates as a means of monitoring rocky shore cryptofauna

Abstract: Two types of artificial substrate (nylon pan-scourers) have been shown to be highly efficient collectors of cryptofauna on rocky shores. The communities which develop in them are closely similar to those which develop in naturally occurring red algal turfs in Bantry Bay. The physical structure of the red algae appears to be the prime factor in determining the development of populations of most of the cryptofaunal species studied. In monitoring protocols artificial substrates of the types described here can be substituted for naturally occurring red algae in studies on shore cryptofauna obviating the necessity for destructive sampling of algae and facilitating statistical analysis by providing a standard ‘unit’ of substrate for comparative purposes. Furthermore, recruitment intensity of two species of gastropod has been shown to be similar in the artificial substrates to that in natural turfs

Mortalities of fauna of rocky substrates in south-west ireland associated with the occurrence of Gyrodinium aureolum blooms during autumn 1979

Abstract: Dinoflagellate blooms, chiefly of Gyrodiniwn aureolum Hulburt, occurred along the south and south-west coasts of Ireland in August and September 1978 and mortalities of shore animals and of rainbow trout Salmo gairdneri held in sea cages were described from Dunmanus Bay (Parker, 1980). Since May 1978 four rocky shore sites in Bantry Bay and one in Dunmanus Bay have been monitored monthly (Myers, Cross & Southgate, 1978, 1979). At each site a permanently marked transect is monitored, limpet shell lengths are measured in marked quadrats at M.H.W.N., M.T.L. and M.L.W.N. and settlement, growth and mortality of barnacle species are studied on vertical rock faces. Discoloration of the water was observed at all five monitoring sites in August 1978 but no effects on the littoral or sub-littoral fauna and flora were detected (Cross & Southgate, 1980).In 1979 a reddish-brown discoloration of the water in Bantry and Dunmanus Bays was first observed in early September. Surface water samples taken at the regular sampling sites between 5 and 10 September revealed very high densities of Gyrodinium aureolum. Slight discoloration of the water persisted at Eagle Point until October and at Glengariff Castle until early November. During this period mortalities of shore fauna were observed at four of the regular sampling sites. Highest mortalities were observed at Pointabulloge in Dunmanus Bay. When visited on 8 September many Patella spp. on the transect were either dead or, if alive, could easily be removed. An estimated 75% of Gibbula umbilicalis were lying inverted in rock crevices with partially opened opercula which they could close only slowly.

The cytosolic and mitochondrial aspartate aminotransferases from pig heart. A comparison of their primary structures, predicted secondary structures and some physical properties.

Abstract: 1 A primary structure is presented for mitochondrial aspartate aminotransferase from pig heart based on previously published results [Barra et al (1977) FEBS Lett 83, 241–244; Doonan et al (1979) Ital J Biochem 28, 441–455; Barra et al (1979) Ital J Biochem 28, 456–477, 478–490] and a small amount of extra information given here 2 A detailed comparison is made between the primary structures of the cytosolic and mitochondrial isozymes These are homologous proteins with 47% identity of primary structure and do not differ appreciably in overall polarity 3 Hydrophobic chromatography of the isozymes using alkyl agaroses suggests that the cytosolic but not the mitochondrial isozyme has a hydrophobic patch or pocket capable of binding to the alkyl side chains of the affinity medium 4 Evidence is presented to show that the cytosolic isozyme contains some basic amino acids whose ionizations are not expressed under native conditions The mitochondrial isozyme does not show this effect 5 Predictions of the secondary structures of the isozymes are presented based on four predictive models Minimum predictions are derived on the basis of agreement of three out of four of the individual predictions These agregate predictions underestimate the amount of ordered secondary structure in both isozymes and suggest a relatively low degree of similarity between the isozymes Individual predictive models, on the other hand, reveal greater similarities in secondary structures between the two isozymes

The Regeneration of Virus-Free Plants from Cucumber Mosaic Virus- and Potato Virus Y-Infected Tobacco Explants Cultured in the Presence of Virazole

Abstract: Adventitious shoots regenerated from tobacco explants taken from donor-plants infected with cucumber mosaic virus and potato virus Y, were virus infected. Similar ex-plants cultured in the presence of Virazole were virus-free.

A biochemical genetic analysis of populations of the northern pike, Esox lucius L., from Europe and North America

Abstract: Genetic variation as identified by starch gel electrophoresis and enzyme staining was studied in seven populations of the northern pike, Esox lucius L. Samples derived from populations in northern U.S., Canada, Swedish fresh water, Swedish Baltic, the Netherlands, England and Ireland were analysed for variation at between 10 and 26 enzyme-coding loci. Polymorphism was found to be restricted to three loci: Sod-1 (mitochondrial superoxide dismutase), Ldh-2 (heart-type lactate dehydrogenase) and Got-1 (cytoplasmic glutamateoxalate transaminase). Mean heterozygosity (H) over all seven population samples was estimated to be 0·019. This extremely low variability, relative to reported data for other fish species, is discussed in terms of the structure and possible origins of pike populations.

Placental transfer and neonatal effects of diazepam when administered to women just before delivery

Abstract: SUMMARY Diazepam 10 mg i.v. was administered to 23 patients (test group) just More delivery. The umbilical cord blood was analysed for diazepam and the well-being of neonates in the test group and in a suitable control group (n = 32) was compared using analysis of covariance. Diazepam was detected in neonatal blood about 0.5 min following its administration to mothers. No significant differences in neonatal well-being were detected between the two groups. However, a highly significant inverse relationship was found between the red temperature of the newborn and the concentration of diazcpam in umbilical cord blood.

Plasma angiotensin II and the control of diabetes mellitus.

Abstract: Plasma angiotensin II was measured in twenty patients with poorly controlled non-ketotic diabetes mellitus, and again when blood glucose control improved. Plasma angiotensin II fell significantly improved control, both when patients were supine and fasting overnight, and when studied after 4 h ambulation. The change occurred with improved short-term and longer-term control. It is concluded that the degree of blood glucose control is important when assessing the renin-angiotensin system in diabetic patients.

NMR studies in the heterocyclic series. XX—a carbon-13 NMR study of the structures of N-hydroxybenzotriazole and its acylated derivatives†

Abstract: Assignment of the carbon resonances in nine derivatives of N-hydroxybenzotriazole has been carried out. The 13C NMR method enables tautomeric N-hydroxy and N-oxide and isomeric O- and N-acyl structures to be identified. In DMSO, the predominant tautomer of N-hydroxybenzotriazole was found to be the N-hydroxy form. The structure of the benzoate and methyl and phenyl carbonate esters were likewise established, but for the two latter compounds, hydrolysis of the equilibrating O- and N-acyl isomers imposed some limitations on the usefulness of the technique.

Effect of selected amides on heat-induced changes in milk.

Abstract: The effect of 15 amides and related compounds on the heat stability of milk was investigated; of these urea, biuret, triuret, methyl urea and ethyl urea had a similar stabilizing effect. These 5 compounds reacted with lysine to form a ninhydrin-positive compound, possibly homocitrulline, and with lactose produced Maillard-type browning, but some of the other compounds studied were also capable of participating in one or both of these reactions. The only effect which the 5 stabilizing amides had in common and which the other compounds did not share was a significant pH-buffering capacity in synthetic systems and in milk. It is suggested that urea exercises its stabilizing influence in milk principally through its ability to buffer the pH of the system during heating.

Hydrogenolysis of alkyl‐substituted adamantanes, diamantanes, and triamantanes in the gas phase on a nickel‐alumina catalyst

Abstract: Dealkylation of several alkyladamantanes, diamantanes, and triamantanes has been observed in the gas phase with hydrogen at atmospheric pressure on a 30% nickel-alumina catalyst. Yield-temperature profiles show that the optimum temperature for obtaining the pure parent compound in high yield can be as low as 215 °C. The ease of removal of an alkyl substituent depends on whether it is secondary or tertiary on the diamondoid nucleus. Rupture of the diamondoid skeleton requires much higher temperatures (over 280 °C) than dealkylation. The hydrogenolytic degradation of diamantane to adamantane was examined with the aid of molecular mechanics calculations; likely pathways for CC bond cleavage were deduced which are consistent with the several intermediates detected experimentally. The mechanism of dealkylation is discussed in terms of steric and thermodynamic factors and the nature of possible surface intermediates. Hydrogenolyse von alkylsubstituierten Adamantanen, Diamantanen and Triamantanen mit Nickel-Aluminiumoxid-Katalysatoren in der Gasphase Bei der Gasphasen-Hydrogenolyse verschiedener Alkyladamantane, Diamantane und Triamantane unter Normaldruck mit Wasserstoff an einem Nickel-Aluminiumoxid-Katalysator wurde glatte Dealkylierung beobachtet. Die optimale Temperatur zur Erzeugung des reinen Grundkorpers in guten Ausbeuten kann den Temperaturprofilen entnommen werden. Die optimale Dealkylierungstemperatur zeigt starke Abhangigkeit von der Position (sekundar oder tertiar) der Alkylgruppe am Kafigmolekul. Die Zerstorung des Kafig-Grundkorpers erfolgt erst bei wesentlich hoheren Temperaturen als die Dealkylierung. Der hydrogenolytische Abbau des Diamantans zu Adamantan wurde untersucht, und der wahrscheinlichste Reaktionsweg wird mit der Hilfe von Kraft-Feld-Rechnungen diskutiert. Unter Berucksichtigung von sterischen und thermodynamischen Faktoren sowie der Natur moglicher Zwischenstufen an der Katalysatoroberflache wird ein Dealkylierungs-Mechanismus vorgeschlagen.

Ohm's law and the definition of resistance

Abstract: In a recent article in this magazine Johnstone and Mughol (1978) drew attention to the struggle many pupils have in understanding the concept of electrical resistance. Much pedagogical clarity is to be gained if distinctions are made between definitions of physical quantities on the one hand and relationships between quantities ('laws') on the other. The author investigates how such clarity might be achieved in the case of Ohm's law.

The Predictability of Counterexamples

Abstract: When teaching mathematics, one is often faced with the task of convincing a student that the converse of a given theorem is false or that the theorem is as strong as possible. The usual method involves the production of a counterexample. However, even a quick glance at a wide range of textbooks shows a singular lack of variety in the counterexamples exhibited, arising no doubt from a lack of imagination on the part of the authors. Indeed, an inexperienced student might be led to conjecture that the following statements are theorems: 1. The function f(x) = IxI is the only real function that is continuous but not differentiable. 2. The real interval [0,1] is the only uncountable set. 3. The function defined on [0,1] by