Showing papers by "University College Dublin published in 1976"
TL;DR: The ultrastructure of the arterial supply of the human placenta was studied in 15 pregnancies with severe fetal growth retardation and in both hypertensive and normotensive patients the spiral arteries and basal arteries of the decidua showed occlusive atheromatous lesions with considerable fibrin deposition and accumulation of lipid‐laden cells.
230 citations
150 citations
TL;DR: In this paper, normal coordinate analyses of a series of chromium (III) dithiocarbamates are reported and the Ugo-Bonati distinguishing monodentate and bidentate bonding by the number of observed bands in the 1000 cm −1 region is shown to be valid, provided comparison is made between complexes containing the same alkyl group.
99 citations
TL;DR: Four inhibitors of alpha-amylase (EC 3.2.1.1) were separated from an alcohol extract of wheat by ion-exchange chromatography on DE52-cellulose and one inhibitor showed the greatest specificity for human salivary amylase relative to human pancreatic amylases.
99 citations
TL;DR: In this paper, the classic Horiuti-Polanyi mechanism of hydrogenation of olefins and competitive reactions for cycloalkenes was discussed, and the αβ process propagates readily along a chain of carbon atoms, and, in acyclic paraffins with rapid rotation about C-C bonds, every H atom is readily replaced, as evidenced by the very large quantities of the perdeutero isomer in initial products from exchange of n-hexane on Pd films.
Abstract: Publisher Summary This chapter focuses on stereochemical approaches to mechanisms of hydrocarbon reactions on metal catalysts. The chapter discusses the classic Horiuti–Polanyi mechanism of hydrogenation of olefins and describes competitive reactions for hydrogenation of cycloalkenes. Some basic facts are established from exchange with deuterium of numerous alkanes and polycycloalkanes especially on Pd catalysts. The interconversion of monoadsorbed and αβ-diadsorbed species can be very rapid especially on Pd and Rh before desorption of alkane. This interconversion is referred to as the “αβ process.” The αβ process propagates readily along a chain of carbon atoms, and, in acyclic paraffins with rapid rotation about C–C bonds, every H atom is readily replaced, as evidenced by the very large quantities of the perdeutero isomer in initial products from exchange of n-hexane on Pd films. The propagation of the exchange reaction is blocked if the chain of carbon atoms contains a quaternary center or a bridgehead.
77 citations
TL;DR: In a study of neutrino interactions occurring in nuclear emulsion, an event has been found that is most readily interpreted as the decay of a charmed particle with lifetime a few times 10 −13 s as mentioned in this paper.
43 citations
TL;DR: The results support the possibility that idiopathic hypercalciuria in many cases represents an early or mild form of 'normocalcaemic' primary hyperparathyroidism and conflict with both the alimentary calcium hyperabsorption theory and the renal calcium leak theory of the aetiology of idiopATHic hyperCalciuria.
Abstract: Serum ionized calcium was shown to be significantly elevated in a group of twenty-eight subjects with idiopathic hypercalciuria in whom the mean total serum calcium concentration was within normal limits. Measurement of parathyroid hormone levels confirmed that elevated values are suppressible by infusion of calcium. Ten subjects with simultaneous elevation of serum ionized calcium and parathormone levels above 3 S.D. of normal were referred for neck exploration, and a parathyroid adenoma was found and removed in nine. Significant decreases to normal values of serum ionized calcium and parathormone levels of urine and calcium excretion were documented some weeks following operation. The results conflict with both the alimentary calcium hyperabsorption theory and the renal calcium leak theory of the aetiology of idiopathic hypercalciuria, and support the possibility that idiopathic hypercalciuria in many cases represents an early or mild form of 'normocalcaemic' primary hyperparathyroidism.
40 citations
TL;DR: In this paper, a new algorithm is presented for reducing trajectory sensitivity for the optimal linear regulator problem, which is shown to yield improvements over existing methods for a first-order example.
Abstract: A new algorithm is presented for reducing trajectory sensitivity for the optimal linear regulator problem. Results for a first-order example yield improvements over existing methods.
36 citations
TL;DR: In this paper, a model designed to incorporate external influences through the labour and goods markets on the rates of domestic wage and price inflation is specified and estimated from postwar Irish data, and an appropriate modification of the two-stage least-squares estimation technique is used.
30 citations
TL;DR: The fresh bark of Picea sitchensis contains astringin as the major stilbene; isorhapontin and piceid are present in minor amounts as discussed by the authors.
28 citations
TL;DR: The associated production of charmed particles by the interactions of 300 GeV/c protons with complex nuclei has been sought using nuclear emulsions as discussed by the authors, and the failure to observe any candidates for this process among some 60,000 interactions investigated implies, provided charmed particle lifetimes are in the range 10 −12 to 10 −14 s, a cross section for their associated production by the interaction of 300 GV/ c protons and nucleons of less than 1.5 microbarns at a 90% confidence level.
TL;DR: It is confirmed that a true rise in metabolically active cortisol occurs during pregnancy and falls to non‐pregnant levels at six weeks post partum.
01 Dec 1976
TL;DR: The first haemopoietic centres in the embryo of Pterophyllum scalare are found in the blood islands of the yolk sac, in contrast to the classical theory of blood formation in teleosts, which maintains that the first blood formation occurs intraembryonically.
Abstract: The first haemopoietic centres in the embryo ofPterophyllum scalare are found in the blood islands of the yolk sac. These results are in contrast to the classical theory of blood formation in teleosts, which maintains that the first blood formation occurs intraembryonically, in the so-called intermediate cell mass of Oellacher. InPterophyllum, the intermediate cell mass forms only the axial blood vessels. Haemopoiesis in the post-embryo is carried out by the pronephros. This organ remains haemopoietic to the adult stage. In the adult, the pronephric tubules are degenerated; the organ is filled with haemopoietic tissue and also contains strands of adrenal tissue. The adult kidney (mesonephros) is also haemopoietic, though to a much lesser degree than the pronephros.The blood islands in the yolk sac form only stem cells (haemocytoblasts) and proerythroblasts. Released into the circulation, they differentiate and mature into round, disc-like erythrocytes (erythrocytes-E). Erythropoiesis in the pronephros produces elliptical erythrocytes (erythrocytes-ImA). Thus for the latter part of the postembryonic phase, until complete absorption of the yolk, there is a mixed erythrocyte population in circulation. During metamorphosis into the laterally-compressed adult, the adult type of erythrocyte (erythrocyte-A) makes its first appearance. Leucocytes and thrombocytes appear much later in development than the red blood cells. They are formed in the pronephros and are seen in circulation only after the yolk has been absorbed.
TL;DR: In a series of diphenyl and related ligand tricarbonylchromium complexes, the 13 C NMR chemical shifts of the ring carbons directly complexed to the metal are about 35 ppm upfield relative to the free ligand, while those of the uncomplexed ring (with the exception of C(1′)) change by no more than 1-2 ppm as mentioned in this paper.
TL;DR: No difference was observed between euthyroid subjects and patients with thyroid disease for any of the three parameters tested, which are discussed in the light of earlier reports linking thyroid activity with the levels of corticosteroid binding globulin.
Abstract: Summary. Plasma cortisol, cortisol resin uptake ratio and free cortisol index was measured in twenty-seven euthyroid, ten hypothyroid and fifteen hyperthyroid subjects. No difference was observed between euthyroid subjects and patients with thyroid disease for any of the three parameters tested. The significance of these findings is discussed in the light of earlier reports linking thyroid activity with the levels of corticosteroid binding globulin.
TL;DR: In this paper, the authors developed an important branch of settlement history by mapping the relict features of deserted villages and fields to increase the knowledge of the evolution of settlement and field-patterns.
01 Sep 1976
TL;DR: In this article, it was shown that the number of elements x ∈ G such that x p = 1 is at most (p | G |)/( p + 1) when G is a Frobenius group of order p (p + 1), p a Mersenne prime.
Abstract: Let G be a finite group, p a prime divisor of | G | and suppose that G is not a p -group. In this note, we show that the number of elements x ∈ G such that x p = 1 is at most ( p | G |)/( p + 1). This answers a question posed by D. MacHale. When G is a Frobenius group of order p ( p + 1), p a Mersenne prime, the above bound is attained.
TL;DR: In general, muscles from high-line mice appeared to contain a larger number of smaller fibres than low- line mice in which there were fewer but wider fibres in the unselected control population from which the lines were derived.
Abstract: M. biceps brachii and m. tibialis anterior were studied at a fixed body weight in mice selected for high and low body weight at a fixed age. Muscle weights were approximately equal in the two lines. In general, muscles from high-line mice appeared to contain a larger number of smaller fibres than low-line mice in which there were fewer but wider fibres than in the unselected control population from which the lines were derived.
TL;DR: A sea-level cosmic ray burst detector was in operation at the time of occurrence of 16 Vela bursts, between 1970 and 1973 as discussed by the authors, but no events were seen, and the upper limits for primary γ-rays of 1011 eV or higher were set at 10−29 erg cm−2 Hz−1.
Abstract: A sea-level cosmic ray burst detector was in operation at the time of occurrence of 16 Vela bursts, between 1970 and 1973. No events were seen. Upper limits for primary γ-rays of 1011 eV or higher were set at 10−29 erg cm−2 Hz−1.
Journal Article•
TL;DR: In this article, the effects of silvicultural treatments on tracheid length and wood density were assessed in a 37 years old stand of Sitka spruce in Knockrath Woodlands, Laragh, Co. Wicklow.
Abstract: The influence of tracheid length and density in Sitka spruce upon wood properties has been demonstrated by several studies and it has been shown that there is a definite correlation between tracheid length and the tensile strength of paper. Wood density is the simplest index of the suitability of wood for many important uses. The effects of silvicultural treatments on tracheid length and wood density should be assessed in this context. Wood samples for all of the preliminary experiments described in this paper were obtained from a 37 years old stand of Sitka spruce in Knockrath Woodlands, Laragh, Co. Wicklow. The results of the experiment showed that spacing did not have a statistically significant influence on tracheid length, but it did have a statistically significant influence on wood density. It is demonstrated that mean density decreased with increased spacing. If it is true that both spacing and canopy closure have an effect on wood density, then it could be expected that this variation would normally disappear as the more closely spaced trees are thinned, or as the wider spaced trees close canopy...
TL;DR: In this paper, a radio system with all sky viewing antennas at 151 MHz was operating at 5 widely spaced stations over the period 1970-1973, during which 19 Vela γ-ray bursts were detected.
Abstract: Radio systems with all sky viewing antennas at 151 MHz were operating at 5 widely spaced stations over the period 1970–1973, during which 19 Vela γ-ray bursts were detected. The records were analysed for each Vela time but no radio coincidences were recorded. A new experiment in the radio band operating at 408 MHz with similar objectives is now under construction and will be described. Five radiometers at 10 GHz have been tracking the Perseus cluster of galaxies for over one year. The supernova reported on 1 March in Perseus occurred during our oberving time but failed to give evidence from prompt emission in excess to 8×10−11 erg cm−2 event−1, for event durations 0.3–100 s.
TL;DR: A wide variety of polynuclear cobalt carbonyl complexes bring about the title reaction but only in the presence of a Lewis acid cocatalyst as mentioned in this paper, but not in the case of a non-coarse Lewis acid.
TL;DR: Glycophosphosphingolipids have been isolated from both plant and fungal sources and contain either one or two mol of inositol phosphate per mol of lipid.
Abstract: The glycophosphosphingolipids are a group of sphingolipids characterized by the presence of equimolar amounts of long-chain base and fatty acid (ceramide) and containing either one or two mol of inositol phosphate per mol of lipid. From one to several mol of sugar are also present. Glycophosphosphingolipids have been isolated from both plant and fungal sources. Work in this area had for years been the province of Herbert Carter and colleagues. They showed that such glycolipids occurred in seeds from corn, flax, soya beans and bean leaves (Carter et al., 1958; Carter & Koob, 1969). The major glycolipid from corn seed had the structure (Carter et al., 1969):
TL;DR: In this paper, the authors investigated the loss in vacuo of RaB atoms by alpha recoil from radon daughter deposits collected with membrane filters and found that the recoil loss efficiency ranges from less than 20 to approx. 100% for the different filter types examined.
TL;DR: In this paper, the amount of excess ionization produced in the lower ionosphere by various transient X-and γ-ray bursts under different assumptions about the incident spectrum and the ion recombination rates in the ionosphere is presented.
Abstract: Calculations are presented of the amount of excess ionization produced in the lower ionosphere by various transient X- and γ-ray bursts under different assumptions about the incident spectrum and the ion recombination rates in the ionosphere. These calculations show that the bursts will have only a small effect on the ionosphere, due in part to their short duration. An experiment has been started to measure the power spectrum of the phase and amplitude of the night-time fluctuations of a CW signal in order to determine if it is possible to improve the sensitivity of the ionospheric technique by using the transient nature of the bursts. Preliminary results from this experiment are presented.
TL;DR: Two 1.5 m reflectors have been used in coincidence, observing the Crab Nebula for pulsed γ-rays of about 5·1012 eV in 1972 and 1973.
Abstract: Two 1.5 m reflectors have been used in coincidence, observing the Crab Nebula for pulsed γ-rays of about 5·1012 eV. About 600 000 showers were observed in 1972 and 1973. The overall results show no significant effect, but some runs showed anomalies, which could be consistent with a real but variable emission.
TL;DR: Farrington's 1947 hypothesis that the Knockmealdown Mountains were a glacial nunatak is tested and confirmed as mentioned in this paper, and the unglaciatcd area was considerably less than Farrington suggested and the maximum altitude reached by the ice around the mountains appears to have been around 365 m.
Abstract: Farrington's 1947 hypothesis that the Knockmealdown Mountains were a glacial nunatak is tested and confirmed. The unglaciatcd area was considerably less than Farrington suggested and the maximum altitude reached by the ice around the mountains appears to have been around 365 m.