Showing papers by "University College Cork published in 1984"
01 Jan 1984
TL;DR: As a consequence of the non-spherical symmetry of the copper(II) ion, d9 configuration, and of the influence of the Jahn-Teller, and pseudo Jahn Teller effect on six-coordinate geometries, the stereochemistries of copper( II) ion are characterized by non-rigid geometry (fluxional behaviour), and ranges of distorted geometry (Plasticity Effect) The latter may be connected by a series of Structural Pathways, which may be characterised by an "Electronic Criterion of Stereochemistry
Abstract: As a consequence of the non-spherical symmetry of the copper(II) ion, d9 configuration, and of the influence of the Jahn-Teller, and pseudo Jahn-Teller effect on six-coordinate geometries, the stereochemistries of the copper(II) ion are characterized by non-rigid geometries (fluxional behaviour), and ranges of distorted geometries (Plasticity Effect) The latter may be connected by a series of Structural Pathways, which may be characterised by an ‘Electronic Criterion of Stereochemistry’ for a related series of complexes, eg the [Cu(bipy)2X] [Y] complexes
441 citations
TL;DR: In this article, the unusual potential/pH behavior of hydrous oxide layers grown on iridium under potential cycling conditions is interpreted on the basis of a model which describes the interaction between the acid-base and redox properties of this type of system.
175 citations
TL;DR: In this paper, the efficiency of the multicycling procedure for producing oxide films on iridium in acid media was observed to decrease with increasing pH, the effect being almost negligible at pH>3.5.
136 citations
TL;DR: Two strains of Lactobacillus plantarum accumulated H2O2 when grown aerobically in a complex glucose based medium and the induction of NADH oxidase responded to lower levels of O2 than the pyruvate oxidase or the NADH peroxidase.
Abstract: Two strains of Lactobacillus plantarum accumulated H2O2 when grown aerobically in a complex glucose based medium. The H2O2 accumulation did not occur immediately on exposure of the culture to O2 but was delayed for a time which, in the case of one strain, was dependent on the amount of inoculum used to seed the culture. The accumulation was always preceded by an increase in the rate of O2 utilization by the cultures. The latter coincided approximately with an increase in specific activity of NADH oxidase, pyruvate oxidase and NADH peroxidase. H2O2 was not a product of NADH oxidase in vitro but was formed in substantial quantities from O2 during oxidation of pyruvate. The three enzymes were induced by O2 and H2O2; the induction of NADH oxidase responded to lower levels of O2 (but not of H2O2) than the pyruvate oxidase or the NADH peroxidase.
80 citations
TL;DR: In this article, the formation and reduction of Ni(II) species was observed at low potentials, about 0.3 V (RHE), and a much thicker hydrous film was produced by repetitive potential cycling.
77 citations
TL;DR: While periodontal disease was significant related to oral hygiene at the outset, neither factor was significantly related to the degree of tooth loss, and a poorer prognosis was found for the teeth with destructive periodonta disease in the younger age group.
Abstract: 1016 textile workers were examined during a baseline study in 1969/70. A follow-up examination in 1979/80 identified 82 subjects who had not been treated for periodontal disease in the intervening period. There were 39 male and 43 female subjects; the average age at the initial examination was 27.0 years. There was an average tooth loss of 2.5 (SEM 0.6) teeth per subject over the 10-year period. While periodontal disease was significantly related to oral hygiene at the outset, neither factor was significantly related to the degree of tooth loss. A detailed analysis of the dynamics of the periodontal condition was undertaken. The subsequent results are presented in the form of transition matrices and clearly illustrate both the progression of periodontal disease and the degree of tooth loss associated with each level of periodontal disease at the initial examination. The main findings are as follows. (a) Overall 6% of teeth initially free of periodontal disease (P.I.O.) were lost compared to 14% with destructive periodontal disease (P.I.6). (b) Progression of periodontal disease was slow for teeth initially free of periodontal disease and with mild gingivitis (P.I.0 and P.I.1) for all age groups. However severe gingivitis (P.I.2), resulted in more rapid deterioration of the supporting tissues in subjects over 35 years old at the final examination; 35% of such teeth changed to destructive periodontal disease (P.I.6) compared to 17% of corresponding teeth for the under 35-year age group. In contrast, a poorer prognosis was found for the teeth with destructive periodontal disease (P.I.6) in the younger age group.(ABSTRACT TRUNCATED AT 250 WORDS)
74 citations
TL;DR: The growth rate of Lactobacillus plantarum in a complex medium with 55.6 mM glucose decreased during aerobic incubation (relative to anaerobic incubation) and the decrease occurred much earlier than an increase in the rate of oxygen utilization by the culture which led to H2O2 accumulation.
Abstract: The growth rate of Lactobacillus plantarum in a complex medium with 55.6 mM glucose decreased during aerobic incubation (relative to anaerobic incubation). The decrease occurred much earlier than an increase in the rate of oxygen utilization by the culture which led to H2O2 accumulation. The concentration of H2O2 accumulated in the medium was easily tolerated by the culture and elimination of the H2O2 did not prevent the decrease in growth rate. Increased O2 utilization was accompanied by a switch in metabolism which resulted in acetate rather than lactate accumulation in aerobic cultures.
67 citations
TL;DR: In this article, the formation of hydrous oxide films on platinum under triangular potential cycling conditions was investigated as a function of sweep-rate, sweep limits, and solution pH, showing that for reasonably short cycling time (<15 min at 100 V s−1) loss of platinum due to dissolution was virtually negligible.
66 citations
TL;DR: In this article, the methylation of toluene with methanol has been compared over unmodified Zeolite HZSM-5 and over HZ SM-5 samples that were partially or fully poisoned with preadsorbed quinoline or trimethylphosphite (TMP).
65 citations
TL;DR: In this article, it was shown that hydrous oxide growth on iridium under potential cycling conditions is possible in dilute, though not strong, base (0.1 and 1.0 mol dm −3 NaOH, respectively).
53 citations
TL;DR: The detailed structure of deuterated Cu(II) Tutton's salt has been determined at 5, 50, 123, 150, 203, 250, 295, and 295 K by neutron powder diffraction as mentioned in this paper.
TL;DR: The acetolactate synthase of Leuconostoc lactis NCW1 was studied and it was allosteric with at least two binding sites for pyruvate and was inhibited by several products of glucose metabolism.
Abstract: The acetolactate synthase of Leuconostoc lactis NCW1 was studied. The Mn 2+ content of cell free extracts was 3·2 µ/mg protein. The enzyme did not require Mn 2+ for activity, had an optimum pH between 5 and 6 and was labile. Incubation at 21 °C or addition of thiamine pyrophosphate followed by storage at 4 °C stabilized the enzyme. It was allosteric with at least two binding sites for pyruvate and was inhibited by several products of glucose metabolism (6-phosphogluconate, 3-phosphoglycerate, 2-phosphoglycerate, PEP and ATP) at pH 5·4. Except for ATP, which became more inhibitory, the inhibition disappeared completely (6-phosphogluconate, 2-phosphoglycerate, and PEP) or partly (3-phosphoglycerate) at pH 4·7. The role of these compounds in the regulation of acetoin production from citrate by leuconostocs is discussed.
TL;DR: In this article, temperature-programmed desorption spectra (TPDS) was used to detect desorbing of D2O from several distinguishable surface configurations for each crystal face.
TL;DR: Seven species of the amphipod genus Ericthonius are described and figured from the North-east Atlantic and associated seas and a key to their identification is provided.
Abstract: Seven species of the amphipod genus Ericthonius are described and figured from the North-east Atlantic and associated seas and a key to their identification is provided. West Atlantic material is also considered where relevant to the taxonomy of East Atlantic species. Two species are re-established after a long period of submersion in synonymy, and one species new to science is described. The previous confusion in the literature of some of the species is discussed, and a synonymy of species described in key works is provided.
TL;DR: In this paper, the formation of hydrous oxide films on gold in base under potential cycling conditions was investigated and found to be less inhibited than the same type of reaction observed when gold is strongly anodized at high potentials under dc conditions at high pH.
Abstract: The formation of hydrous oxide films on gold in base under potential cycling conditions was investigated and found to be less inhibited than the same type of reaction observed when gold is strongly anodized at high potentials under dc conditions at high pH The overall behaviour on cycling is quite similar to that observed with other metals, eg platinum The importance of the lower limit, for instance, again appears to be related to the need under film thickening conditions to significantly reduce the compact oxide layer formed on the metal surface during the anodic sweep It was noted that the earlier duplex model for this type of system, ie an inner compact and an outer dispersed oxide layer, is not always valid Under certain conditions about six distinct peaks (suggesting six different states of gold oxide hydration, dispersion or polymerization) were observed in cathodic sweeps recorded for the reduction of thick films grown on gold under potential cycling conditions in base
TL;DR: A sequence of events consistent with known facts about the transport of proteins into or through the mitochondrial membrane systems is provided and provides a framework for future investigations.
Abstract: There is still much that is obscure concerning the transport of proteins into or through the mitochondrial membrane systems. In addition, as pointed out previously, it is unlikely that the details of the process are the same for proteins destined for different compartments of the organelle. A brief summary of the process for matrix proteins might be as follows: The proteins are synthesized on free polysomes as precursors of higher molecular weight than the native forms. These precursors are liberated into the cell cytosol and subsequently translocated into the mitochondria. This timing might be different in yeast under some circumstances, synthesis being completed in association with the mitochondria. The precursors interact with a receptor in the outer mitochondrial membrane interaction being mediated by the presequences of the precursors. The presequences therefore act as addressing signals as well as possibly playing a role in one or all of (a) solubilization of precursors, (b) prevention of premature assembly into multimeric structures, or (c) maintenance of nonnative configurations required for transport. Interaction occurs with a second receptor, this time in the inner membrane of the mitochondria, interaction being with multiple sites in the polypeptide chain. Transport across the inner membrane then occurs, this transport depending on a transmembrane electrochemical gradient of which the proton component is the essential part. Transport is accompanied or followed by proteolysis of the prepiece, and formation of the native structure. While steps 1 and 2 of this sequence can be considered well established, the remaining steps are still poorly understood or purely hypothetical. Nevertheless, this sequence of events is consistent with known facts about the process and provides a framework for future investigations.
TL;DR: La mort selective des animaux due a la proliferation de G.a. species est suivie d'un colonisation par les Enteromorpha des Pheophycies and d'une recolonisation par une faune analogue.
Abstract: The mortalities and subsequent recolonization of a rocky shore in S.W. Ireland following a bloom of the toxic dinoflagellate, Gyrodinium aureolum in 1979 are described. Selective mortalities of key animal species notably grazing gastropods were followed by a marked increase in fucoid algae. Enteromorpha spp. blooms were a feature of vertical surfaces only. In general planktonic recruiting gastropods exhibited the most rapid recovery. Forty-two months after the red tide, fucoid algae still dominate both vertical and horizontal surfaces at the study area.IntroductionDinoflagellate blooms ('red-tides'), chiefly of Gyrodinium aureolum Hulburt have been recorded several times in Southern Ireland since 1976 (Ottway et al. 1979; Cross & Southgate, 1980; Jenkinson & Connors, 1980; Leahy, 1980; Roden, Ryan & Lennon, 1980; Wilson, 1982) and have resulted in mortalities of farmed rainbow trout in sea-cages in Dunmanus Bay (Parker, 1981). Other species of pelagic and demersal fish on the south coast were also affected by a toxic red-tide in 1976 (Ottway et al. 1979). Owing to the unpredictability of occurrence of dinoflagellate blooms, few studies on the effects of red tides on littoral fauna, and on the subsequent recolonization following the events have been carried out. Previous studies in Dunmanus Bay, Ireland (Leahy, 1980) suffered from a lack of the shores prior to the of information about the structure and dynamics occurrence of a red-tide.Regular monitoring of the rocky shore biota at Dunmanus Bay (Myers, Southgate & Wilson, 1980) has been carried out since May 1978 and is continuing. The red tide of August 1979 caused dramatic mortalities of a wide range of taxa at Pointabulloge in Dunmanus Bay (Cross & Southgate, 1980).
TL;DR: Growth analysis of the progeny plant populations show differences in plant diameter, leaf number, leaf area and petiole length between tissue culture progenies and those derived from leaf cuttings.
TL;DR: Although mutant CJ9 induced nitrogenase activity in an ‘in vitro’ assay system under microaerobic conditions, it failed to fix nitrogen (acetylene reduction) in soybean root nodules and constitute a new Asm − mutant class in Rhizobium spp.
Abstract: A mutant strain of Rhizobium japonicum (CJ9) unable to assimilate ammonium (Asm − ) was isolated following mutagenesis with N -methyl N -nitro-nitrosoguanidine (NTG). Glutamate synthase activity was not detectable in cell-free extracts of the mutant strain in contrast to the wild type and revertant strains. Although mutant CJ9 induced nitrogenase activity in an ‘in vitro’ assay system under microaerobic conditions, it failed to fix nitrogen (acetylene reduction) in soybean root nodules. These properties of mutant CJ9 constitute a new Asm − mutant class in Rhizobium spp.
TL;DR: There is now, however, evidence to suggest that some prokaryotes possess a copper/zinc enzyme related to the eukaryotic cytosolic form, and the possibility arises that primitive proKaryotes possessed both proteins.
TL;DR: In this paper, a path analysis which treats the personal variables as causally antecedent was tested in Cork, Ireland, and showed neighbourhood satisfaction to be a direct result of four perceived attributes and two personal characteristics, which together explain 38% of the variation in satisfaction.
Abstract: Many studies of residential satisfaction have shown that the effect of residents' personal characteristics is mediated through their perceptions and evaluations of attributes of their neighbourhoods, but have not been able to show how this occurs. A path analysis which treats the personal variables as causally antecedent was tested in Cork, Ireland. This shows neighbourhood satisfaction to be a direct result of four perceived attributes and two personal characteristics, which together explain 38% of the variation in satisfaction. The other personal variables are mediated through these direct causes and contribute indirectly to satisfaction levels.
TL;DR: This site specific transposition of Tn7 in R. meliloti provides an additional genetic tool to further manipulate this important plasmid in symbiotic nitrogen fixation.
Abstract: Transposon Tn7 was shown to insert specifically into the megaplasmid of different Rhizobium meliloti strains. Tn7 transposition could not be detected in other Rhizobium strains such as R. trifolii, R. leguminosarum, R. phaseoli and R. japonicum. In R. meliloti strains, two unique sites in the megaplasmid were observed into which Tn7 can transpose at different frequencies. Only one copy of Tn7 could be detected in the megaplasmid and the insertion sites for Tn7 are outside the nif and nod region. Tn7 transposition in R. meliloti showed a marked preference for sites on plasmid RP4 compared to the megaplasmid sites. Attempts to cure Tn7 from the megaplasmid were unsuccessful. This site specific transposition of Tn7 in R. meliloti provides an additional genetic tool to further manipulate this important plasmid in symbiotic nitrogen fixation.
TL;DR: In this article, Gaussian 80 (6-21G) calculations were performed in both HF and CI modes on the species SiHn (n = 1-4) and SiHm+ (m = 1−5).
Abstract: Gaussian 80 (6-21G) calculations were performed in both HF and CI modes on the species SiHn (n = 1–4) and SiHm+ (m = 1–5). In general the agreement between calculated and experimentally determined properties such as the structures of SiHn molecules and the ionisation potentials of SiH4 were very good. The present results were compared with those previously published. The production of the ions SiH3+ and SiH2+ in the electron impact mass spectrum of silane was also analysed.
TL;DR: A response to barney O'Reilly on curriculum and policy in Irish post-primary education is given in this article, where O'Brien discusses curriculum and policies in Irish education.
Abstract: (1984). A response to barney O'Reilly on curriculum and policy in Irish post‐primary education. Irish Educational Studies: Vol. 4, No. 2, pp. 33-46.
TL;DR: In this article, the crystal and molecular structure of the tetraethylammonium salt of the tricarbonylmolybdenum complex of III, i.e. [NEt4][Mo(CO)3HB(C4H5N2)3] (IV) has been determined.
TL;DR: In this paper, the impact of strategic diversification on a market-based measure of firm risk is examined, and the results cast further doubt on risk reduction as a general motive for diversifying merger, although they do not support the positive association between systematic risk and conglomerate status.
Abstract: This paper presents some empirical tests of the impact of strategic diversification on a market-based measure of firm risk. Instead of considering merely the consequences of isolated diversifying mergers, as most previous work in this area has done, the study examines the impact of all quoted acquisitions over a five year period using a sample of 100 large companies and a period of intense merger activity. The results cast further doubt on risk reduction as a general motive for diversifying merger, although they do not support the positive association between systematic risk and conglomerate status found in many US studies.