Showing papers by "Queen's University Belfast published in 1976"
TL;DR: The R-matrix concept of atomic processes was first introduced by Wigner and Eisenbud as mentioned in this paper with the fundamental idea that configuration space describes the scattered particle, and the target is divided into two regions.
Abstract: Publisher Summary This chapter discusses the R-matrix concept of atomic processes. The R-matrix method was first introduced by Wigner and Eisenbud with a fundamental idea that configuration space describes the scattered particle, and the target is divided into two regions. In the internal region (r
498 citations
TL;DR: In this paper, the adsorption of Telon Blue (Acid Blue 25) on peat has been investigated and the effects of contact time, initial dye concentration and peat particle size were studied.
450 citations
TL;DR: In this article, the ability of wood to adsorb Telon Blue (Acid Blue 25) has been investigated and the effects of contact time, particle size and adsorption capacity have been studied.
193 citations
TL;DR: It is suggested that the increase in synthesis at this time may result from an increase in both the abailability and active involvement of ribosomes, and that these anabolic trends may be caused by spontaneous fibrillation and/or the amount of passive stretching of the denervated muscles.
Abstract: The effects of denervation on muscle weight, rates of protein synthesis and breakdown, and RNA concentraitons were studied in the soleus and extensor digitorum longus muscle. Althrough the soleus underwent a true atrophy after section of the sciatic nerve, the extensor digitorum longus continued to grow, albeit at a lower rate than innervated controls. At 24h after nerve section protein breakdown was increased in both muscle types when compared with internal controls, and remained so throughout the 10 days studied. The possibility that this increased catabolism might arise from conformational changes of proteins after denervation was not substantiated, as myofibrillar or soluble proteins of denervated and control tissues were equally susceptible to degradation in vitro by three proteinases. Tyrosine uptake into the denervated extensor digitorum longus was decreased throughout the 10 days studied, whereas two phases of increased transport of the amino acid were found in the soleus. Significant decreases in rates of protein synthesis were found 1 and 2 days after denervation and results are presented that suggest that these changes may result from a decrease in ribosomal involvement in the translation process. These initial decreases were not maintained and the rate of protein synthesis was in fact increased when compared with controls, at 7 and 10 days. The increased synthetic rates of the 7-day denervated tissues were reflected as proportional increases in both myofibrillar and soluble proteins. It is suggested that the increase in synthesis at this time may result from an increase in both the abailability and active involvement of ribosomes, and that these anabolic trends may be caused by spontaneous fibrillation and/or the amount of passive stretching of the denervated muscles.
177 citations
TL;DR: In this article, a FORTRAN IV algorithm is presented for determining sets of dominant eigenvalues and corresponding eigenvectors of symmetric matrices, which is also extended to the solution of the natural vibration of a structure for which symmetric stiffness and mass matrices are available.
Abstract: A FORTRAN IV algorithm is presented for determining sets of dominant eigenvalues and corresponding eigenvectors of symmetric matrices. It is also extended to the solution of the equations of natural vibration of a structure for which symmetric stiffness and mass matrices are available. The matrices are stored and processed in variable bandwidth form, thus enabling advantage to be gained from sparseness in the equations. Some of the procedures may also be used to solve symmetric positive definite equations such as those arising from the static analysis of structures loaded within the elastic range.
162 citations
01 Oct 1976
TL;DR: In this paper, the authors studied the channel geometry, flow and sedimentation in a meander bend of the River South Esk from bank full stages (January-February) to low water stages (May) in 1974.
Abstract: Channel geometry, flow and sedimentation in a meander bend of the River South Esk were studied from bankfull stages (January–February) to low water stages (May) in 1974. Bed topography varied little over the study period, showing a typical pool and ripple geometry. Variation of mean depth and velocity with discharge differed from section to section around the bend, due primarily to locally varying flow resistance with stage.
The flow pattern for all stages was dominated by a single spiral over the point bar, with a development zone at the bend entrance. Deviation of bed shear stress from the mean flow direction was in general accord with theory, especially for high stages. The use of a uniform longitudinal water surface slope in the calculation of bed shear stress is not justified because of a complicated water surface topography, also such calculated shear may not represent effective bed shear on grains, as it accounts also for energy losses associated with secondary flows.
Dunes covered much of the bar at high stages, with increasing proportions of ripples, sand ribbons and lower phase plane beds at low stages. Local flow resistance generally decreases from dunes, diminished and ripple-backed dunes, ripples, sand ribbons to plane beds, and bed forms are predicted quite well by the stream power-grain size scheme.
Mean size, sorting and skewness of sediment over the bed changes little with stage. In general, size decreases, sorting improves and skewness changes from positive to negative from the talweg to the inner bank, and in the downstream direction. Allen's (1970a, b) force balance equation for moving bed load particles is supported for bankfull stage, with some reservations, and textural characteristics are explained by progressive sorting in the direction of sediment transport.
Large-scale trough cross stratification (with some flat bedding) formed at high stage by dunes (and lower phase plane beds) dominates the point bar sediments. Alternations of fine-medium sand (often cross-laminated) and vegetation-rich layers result from periodic deposition on the grassed upper bar surface.
Fining upwards sequences produced by lateral channel migration are modified by a coarsening upward subsequence in the upstream bar region where spiral flow is developing from the bend upstream.
129 citations
TL;DR: Repeated oral administration of atenolol 200 mg daily either as a single dose or in divided 12 hourly doses for 8 days maintained reduction of an exercise tachycardia of at least 24% during the period of drug administration.
Abstract: The effects of oral and intravenous administration of atenolol were studied in healthy volunteers. The oral administration of a series of single doses of atenolol reduced an exercise tachycardia. After a 200-mg dose, the effect on an exercise tachycardia was maximal at 3 hr and declined linearly with time at a rate of approximately 10% per 24 hr. The peak plasma atenolol concentration occurred at 3 hr and thereafter declined exponentially with time with an elimination half-life of 6.36 +/- 0.55 hr: 43 +/- 3.9% of the dose was excreted in the urine within 72 hr. There was a correlation between the reduction in an exercise tachycardia and the logarithm of the corresponding plasma concentration. The intravenous administration of atenolol reduced exercise tachycardia with a significant correlation between effect and plasma concentration. After 50 mg intravenously, 100% of the dose was recovered from the urine, and the clearance was 97.3 ml/min. Comparison of AUC O leads to chi after oral and intravenous administration of 50 mg showed the bioavailability to be 63% after oral drug. Repeated oral administration of atenolol 200 mg daily either as a single dose or in divided 12 hourly doses for 8 days maintained reduction of an exercise tachycardia of at least 24% during the period of drug administration. The plasma elimination half-life, area under the plasma concentration-time curve, and peak plasma concentration after 200 mg atenolol were not changed by chronic dosing for 8 days.
128 citations
TL;DR: Measurements of the serum bilirubin concentration showed the most frequent abnormalities, but the pseudocholinesterase concentration decreased progressively after intra-abdominal surgery and b.s.o.p.t. retention increased significantly, changes which were probably not related to liver function.
Abstract: Liver function tests carried out after minor surgical procedures, under anaesthesia lasting for 1 hr, showed no abnormalities. Tests after body surface operations under the same anaesthetic techniques showed transient derangements. After intra-abdominal procedures, liver dysfunction was more marked, although no patients with evidence of preoperative liver dysfunction or postoperative surgical complications were studied and none received blood transfusions. Measurements of the serum bilirubin concentration showed the most frequent abnormalities, but the pseudocholinesterase concentration decreased progressively after intra-abdominal surgery and b.s.p. retention increased significantly. Serum concentration of intracellular enzymes (LDH, s.g.o.t. and s.g.p.t.) increased within an hour of starting surgery, changes which were probably not related to liver function.
109 citations
TL;DR: In an attempt to understand the effect of solutes on starch gelatinization, the theory of polymer-amorphous phase transitions has been developed to consider melting in a three component system consisting of polymer, diluent and solute as mentioned in this paper.
106 citations
TL;DR: The fetal crown‐rump length was measured by means of pulsed ultrasound, and the normal values between 47 and 101 days from the onset of the last menstrual period were determined from cross‐sectional data in 253 patients.
94 citations
TL;DR: A family of algorithms that are variations on the Bron-Kerbosch algorithm for finding all the cliques of a simple undirected graph are developed in a stepwise manner from a recursive algorithm for generating all combinations of zero or more objects chosen fromN objects.
Abstract: This paper develops a family of algorithms that are variations on the Bron-Kerbosch algorithm for finding all the cliques of a simple undirected graph. The algorithms are developed in a stepwise manner, from a recursive algorithm for generating all combinations of zero or more objects chosen fromN objects. Experimental results are given.
TL;DR: It is concluded from the high Q10 figures for germination in the cold that the failure of germination may result from a denaturation of proteins.
Abstract: SUMMARY
At 2O°C, cucumber and mung bean seeds germinate rapidly. As the temperature is lowered to 14°C, the time required for 50% germination increases with a Ql0 of about 2. However, between 14 and 11°C, Q10 rises to 60–1600 (cucumber) and 87 (mung bean); below 11°C only a small percentage of seeds will germinate. At 10°C, the roots never extend to more than 1.5 mm, while a length of 2.5 mm is necessary for germination. Exogenous supply of various amino acids and hormones fails to alleviate the block to germination in the cold. The mitotic index of root cells in cucumber seedlings is low at 5°C. However, at 22°C the seeds can germinate even under conditions that inhibit mitosis (0.02% colchicine or following γ-irradiation). There is little indication of leakage from cucumber seeds in the cold. Arrhenius plots of the respiration of imbibed seeds, of the growth of 1-cm long roots and the respiration of root tips are a1! linear. It is concluded from the high Q10 figures for germination in the cold that the failure of germination may result from a denaturation of proteins.
TL;DR: It is suggested that collection of particles for possible ingestion is by way of water currents which flow dorsally in the U-shaped principal filaments rather than by any straining effect by the latero-frontal tracts.
Abstract: Following an examination by transmission and scanning electron microscopy of the latero-frontal tracts on the gills of Nucula sulcata, Ostrea edulis and Chlamys varia, it is suggested that only two types of structure are involved, namely compound eu-latero-frontal cirri and pro-latero-frontal cilia; the terms 9anomalous latero-frontal9, 9para-latero-frontal9 and 9micro-latero-frontal9 should be dropped Each latero-frontal tract of N sulcata consists of a row of compound eu-latero-frontal cirri and four rows of pro-latero-frontal cilia Each cirrus is borne by a single cell and consists of some 20 pairs of cilia arranged in two parallel, alternating rows Individual cilia leave the shaft of the cirrus at regular intervals on each side but there is no stiffening element present in the region of the bend Each latero-frontal tract on the plicate, heterorhabdic gill of O edulis consists of a single row of compound cirri and two alternating rows of pro-latero-frontal cilia The cirri of the principal filaments are spaced 15-20 $\mu $m apart and consist of 10 or 11 pairs of cilia Those on the ordinary filaments forming the crests of the plicae are spaced 25 $\mu $m apart and consist of but 6 or 7 pairs of cilia As in N sulcata, the individual cilia bend to either side of the main axis of each cirrus but, unlike those of N sulcata, a small stiffening element is present in the immediate region of the bend It is concluded that the Ostreidae should not be grouped with the Microciliobranchia The latero-frontal tracts of the plicate, heterorhabdic gills of C varia consist of a single row of pro-latero-frontal cilia only In both O edulis and C varia, mucous glands and sensory ciliary tufts occur mainly along the frontal faces of the ordinary filaments forming the crests of the plicae; the glands of O edulis appear to contain a neutral mucoprotein and those of C varia an acid mucopolysaccharide The principal filaments of C varia are capable of marked changes in form with consequent effects on the nature of the plication of the gill When few particles are presented to the gill the principal filaments are U-shaped in section and form a pronounced gutter at the base of the grooves between adjacent plicae It is suggested that collection of particles for possible ingestion is by way of water currents which flow dorsally in the U-shaped principal filaments rather than by any straining effect by the latero-frontal tracts Correlated with this method of collection the frontal cilia of the principal filaments are arranged in three well defined tracts, all of which beat dorsally When the concentration of particles presented to the gill is increased, the principal filaments temporarily lose their U-shape and, in extreme cases, become T-shaped in section; the current flow referred to above thus breaks down Increased amounts of mucus are secreted by the glands associated with the ordinary filaments and mucus, plus entangled particles, are carried ventrally to the free margins of the demibranchs by the frontal tracts of the ordinary filaments It is suggested that the collection of particles by way of water currents, as proposed for the gill of C varia, has been developed in those bivalves in which the latero-frontal tracts consist of pro-latero-frontal cilia only, that is the Microciliobranchia excluding the Ostreidae In those lamellibranch bivalves in which the latero-frontal tracts consist of compound eu-latero-frontal cirri in addition to pro-latero-frontal cilia, the collection of particles is achieved primarily by the straining action of the cirri and the retained material is transported by direct ciliary action rather than in suspension by water currents
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.
TL;DR: The characteristics of cultured cells persistently infected with RNA viruses, other than leuko viruses are described and the roles that the host cell, interferon, virus mutants and defective interfering particles may play in the establishment and maintenance of persistent infection are discussed.
Abstract: In this paper, the characteristics of cultured cells persistently infected with RNA viruses, other than leuko viruses are described. The roles that the host cell, interferon, virus mutants and defective interfering particles may play in the establishment and maintenance of persistent infection, are discussed.
TL;DR: In this paper, the 1s to 2s and 1s 2p total and differential cross sections for electron impact excitation of atomic hydrogen are calculated from 13 eV to 300 eV.
Abstract: The 1s to 2s and 1s to 2p total and differential cross sections for electron impact excitation of atomic hydrogen are calculated from 13 eV to 300 eV. The 1s-2s-2p close-coupling approximation is used for the low partial waves and the unitarized Born approximation for the high partial waves. At the highest energy up to 500 partial waves are included. The calculated differential cross sections are in quite good agreement with the measurements of Williams and Willis (1975).
TL;DR: The surface of Fasciola hepatica, therefore, has morphological and chemical features very like those proposed for the “greater membrane” by Lehninger.
TL;DR: In this paper, the excitation of the 2P and 2S states of atomic hydrogen by electron impact has been studied by observing separately the prompt (approximately 10-9 s) Lyman- alpha photons from the decay of 2P state, the delayed Lyman alpha photon from the quenched 2S state and the 10.2 eV energy-loss scattered electrons.
Abstract: The excitation of the 2P and 2S states of atomic hydrogen by electron impact has been studied by observing separately the prompt ( approximately 10-9 s) Lyman- alpha photons from the decay of the 2P state, the delayed Lyman- alpha photons from the quenched 2S state and the 10.2 eV energy-loss scattered electrons. Observations of these channels indicate the presence of at least four resonant states at 11.74, 11.85, 11.94 and 12.05 eV (+or-0.080 eV). These energies agree within the experimental error with the positions of the 1S, 1D, 1P and 1S(3P) resonance states predicted by six-state close-coupling theory. Over the first 0.5 eV above threshold, the measured values of the absolute cross section for separate excitation of the 2S and 2P states agree, within the experimental errors of +17% and -15%, with the three-state (1s,2s,2p) plus twenty-correlation-term close-coupling predictions of Taylor and Burke (1967). At incident electron energies of 13.87, 16.46 and 19.58 eV the first low-energy measurements are reported of the differential cross sections for exciting the n=2 states.
TL;DR: In this article, the authors measured diazepam and N-desmethyl concentrations in patients receiving 5 mg or 10 mg i.v. at 4-h intervals for periods of 6-22 days.
Abstract: Plasma diazepam and N–desmethyl diazepam concentrations were measured in patients receiving diazepam 5 mg or 10 mg i.v. at 4–h intervals for periods of 6–22 days. At both doses there was an accumulation of both diazepam and its metabolite, the latter reaching concentrations of up to two to three times that of the parent drug. Plasma diazepam concentrations reached a plateau after 8 days while the concentration of N-desmethyl metabolite continued to increase throughout the period of drug administration. On discontinuation of diazepam therapy both diazepam and N-desmethyl diazepam concentrations decreased slowly, the former with a half-life of 2–4 days and the latter with a half-life of 4–8 days.
TL;DR: Development of the spermatozoa in the testis of a polyopisthocotylean fish-gill fluke, Diclidophora merlangi, has been examined by light and electron microscopy and shows that spermatogonial cells are typically undifferentiated and display numerous free ribosomes and relatively little cytoplasm.
TL;DR: The technique of Bakhvalov and Vasil'eva for evaluating Fourier integrals is discussed and used as the basis for providing computationally efficient and stable algorithms as discussed by the authors.
Abstract: The technique of Bakhvalov and Vasil'eva for evaluating Fourier integrals is discussed and used as the basis for providing computationally efficient and stable algorithms The method is generalized to deal with a number of weight functions including those for the infinite ranges A number of examples illustrate the methods
TL;DR: It is concluded that the oral administration of sotalol either once or twice daily (depending on dose level) will provide satisfactory 24-hour blockade of β-adrenoceptors.
Abstract: The effects of sotalol after oral administration were measured on the tachycardia induced by strenuous exercise in normal subjects. Plasma sotalol levels were also determined. The oral administration of sotalol (50, 100, 200 and 400 mg) to 6 subjects produced a progressive reduction in the tachycardia induced by severe exercise. This was similar to the effects of 25, 50, 100, 200, 400 and 800 mg given to different subjects. Each increase in sotalol dose produced a successively greater reduction in exercise tachycardia. This did not appear to be maximum even with 800 mg. Oral sotalol was rapidly absorbed and produced peak blood levels in 2 - 3 hours. The plasma levels of sotalol measured 2 hours after the oral administration of 25 to 800 mg showed never more than a six-fold variation between different subject. The half-life of sotalol in plasma was 12.7 +/- SE 1.6 hours. There was a significant correlation between the logarithm of the plasma sotalol concentration and the percentage reduction of exercise heart rate. It is concluded that the oral administration of sotalol either once or twice daily (depending on dose level) will provide satisfactory 24-hour blockade of beta-adrenoceptors.
TL;DR: Relative growth has been studied in intertidal populations of Cerastoderma edule and Mytilus edulis and in a subtidal population of Modiolus modiolus and results are interpreted in terms of differences in stability between their respective habitats.
Abstract: Relative growth has been studied in intertidal populations of Cerastoderma edule and Mytilus edulis and in a subtidal population of Modiolus modiolus. Size dimensions were generally more variable and shell thickness generally greater in the intertidal species. Total weight was correlated with shell weight in all three species but there was a progressively greater emphasis on tissue growth through the sequence Cerastoderma, Mytilus, Modiolus. These results are interpreted in terms of differences in stability between their respective habitats.
Analyses of individual year classes in Cerastoderma showed a marked pattern of alternating years of good and poor growth.
TL;DR: It is suggested that during acute starvation the rise in triglyceride concentration results from the increased availability of free fatty acids, and that elevated secretin and glucagon levels enhance lipolysis and hence provide substrates for triglyceride synthesis.
Abstract: Plasma lipid and hormone levels have been measured during 72 hours total starvation in nine healthy subjects, to assess the relative importance of hormones and substrates in human triglyceride metabolism. Plasma free fatty acid and glycerol concentrations rose steadily on each day of starvation. Plasma triglyceride concentrations rose on the second and third days, from a control level of 649 +/- 67 mg/1 to a maximum of 1001 +/- 66 mg/1. Plasma cholesterol concentrations remained unchanged while glucose concentrations fell and insulin did not change. Plasma glucagon (C-GLI) levels doubled while secretin levels, reported previously, rose threefold. It is suggested that during acute starvation the rise in triglyceride concentration results from the increased availability of free fatty acids, and that elevated secretin and glucagon levels enhance lipolysis and hence provide substrates for triglyceride synthesis.
TL;DR: The increase in volume of the human calf and forearm during pregnancy resulting from graded venous congestion has been measured plethysmographically in the raised leg and forearm of 10 recumbent subjects during and after pregnancy.
TL;DR: Fasting for 3 days had no significant effect on the Paneth cell count but after a 4-day fast there was a significant rise in the total Panethcell count accompanied by a fall in the percentage of Paneth cells containing dithizone-reactive zinc in all areas examined.
Abstract: The distribution of Paneth cells in the rat small intestine was found to be approximately one per crypt in the duodenum, two to three per crypt in the jejunum and four to six per crypt in the ileum. The ileum has more Paneth cells containing dithizone-reactive zinc than the duodenum and jejunum. Zinc deficiency had no significant effect on the total Paneth cell count but no dithizone-reactive Paneth cells were found in any area of the small intestine examined in zinc-deficient animals. Fasting for 3 days had no significant effect on the Paneth cell count but after a 4-day fast there was a significant rise in the total Paneth cell count accompanied by a fall in the percentage of Paneth cells containing dithizone-reactive zinc in all areas examined.