Showing papers by "University of Birmingham published in 1974"
TL;DR: In this paper, the critical properties of the xy model with nearest-neighbour interactions on a two-dimensional square lattice were studied by a renormalization group technique, and the correlation length is found to diverge faster than any power of the deviation from the critical temperature.
Abstract: The critical properties of the xy model with nearest-neighbour interactions on a two-dimensional square lattice are studied by a renormalization group technique. The mean magnetization is zero for all temperatures, and the transition is from a state of finite to one of infinite susceptibility. The correlation length is found to diverge faster than any power of the deviation from the critical temperature. Analogues of the strong scaling laws are derived and the critical exponents, eta , and delta , are the same as for the two-dimensional Ising model.
1,546 citations
TL;DR: A new plot is described for analysing the results of kinetic experiments in which the Michaelis-Menten equation is obeyed, and provides clear and accurate information about the quality of the observations, and identifies aberrant observations.
Abstract: A new plot is described for analysing the results of kinetic experiments in which the Michaelis–Menten equation is obeyed. Observations are plotted as lines in parameter space, instead of points in observation space. With appropriate modifications the plot is applicable to most problems of interest to the enzyme kineticist. It has the following advantages over traditional methods of plotting kinetic results: it is very simple to construct, because it is composed entirely of straight lines and requires no calculation or mathematical tables; the kinetic constants are read off the plot directly, again without calculation; it may be used during the course of an experiment to judge the success of the experiment, and to modify the experimental design; it provides clear and accurate information about the quality of the observations, and identifies aberrant observations; it provides a clear indication of the precision of the kinetic constants; constructed with care, it provides unbiased estimates of the kinetic constants, the same as those provided by a computer program; it may be used to simulate results for illustrative purposes very rapidly and simply.
1,457 citations
TL;DR: A tentative theory is proposed to combine various features of the problem which have been revealed by some of the different approaches to the theory of noninteracting electrons in a static disordered lattice.
1,084 citations
TL;DR: A new method is described for plotting kinetic results for inhibited enzyme-catalysed reactions that provides a simple way of determining the inhibition constant, K'(i), of an uncompetitive, mixed or non-competitive inhibitor.
Abstract: A new method is described for plotting kinetic results for inhibited enzyme-catalysed reactions. It provides a simple way of determining the inhibition constant, K′i, of an uncompetitive, mixed or non-competitive inhibitor.
874 citations
TL;DR: The plot is shown to lead directly to non-parametric confidence limits for the kinetic parameters, V and K(m), which depend on far less sweeping assumptions about the nature of experimental error than those implicit in the method of least squares.
Abstract: The statistical implications of the direct linear plot for enzyme kinetic data, described in the preceding paper (Eisenthal & Cornish-Bowden, 1974), are discussed for the case of the Michaelis-Menten equation. The plot is shown to lead directly to non-parametric confidence limits for the kinetic parameters, V and K(m), which depend on far less sweeping assumptions about the nature of experimental error than those implicit in the method of least squares. Median estimates of V and K(m) can also be defined, which are shown to be more robust than the least-squares estimates in a wide variety of experimental situations.
349 citations
TL;DR: In this article, a general-purpose computer program, VIPASA, is presented for determining the critical buckling stresses or natural frequencies of vibration of thin prismatic structures, consisting of a series of plates rigidly connected together along longitudinal edges.
312 citations
TL;DR: In this paper, consistent relationships were found between variables of organization context or task environment (size, dependeness, etc) (i.e., task environment) for manufacturing organizations in three countries.
Abstract: In data in standard form on seventy manufacturing organizations in three countries, consistent relationships are found between variables of organization context or `task environment' (size, depende...
254 citations
235 citations
TL;DR: On electrophoresis in dissociating conditions the Tropomyosins isolated from skeletal muscles of mammalian, avian and amphibian species migrated as two components comparable with the alpha and beta subunits of tropomyosin present in rabbit skeletal muscle.
Abstract: 1. On electrophoresis in dissociating conditions the tropomyosins isolated from skeletal muscles of mammalian, avian and amphibian species migrated as two components. These were comparable with the α and β subunits of tropomyosin present in rabbit skeletal muscle. 2. The α and β components of all skeletal-muscle tropomyosins contained 1 and 2 residues of cysteine per 34000g respectively. 3. The ratio of the amounts of α and β subunit present in skeletal muscle tropomyosins was characteristic for the muscle type. Muscle consisting of slow red fibres contained a greater proportion of β-tropomyosin than muscles consisting predominantly of white fast fibres. 4. Mammalian and avian cardiac muscle tropomyosins consisted of α-tropomyosin only. 5. Mammalian and avian smooth-muscle tropomyosins differed both chemically and immunologically from striated-muscle tropomyosins. 6. Antibody raised against rabbit skeletal α-tropomyosin was species non-specific, reacting with all other striated muscle α-tropomyosin subunits tested. 7. Antibody raised against rabbit skeletal β-tropomyosin subunit was species-specific.
204 citations
TL;DR: Evidence is presented indicating that in the rabbit the inhibitory protein of the troponin complex of red skeletal and cardiac muscles is different from the inhibitatory protein of white skeletal muscle.
Abstract: 1. The molecular weight of the calcium-binding protein of rabbit white skeletal muscle was estimated to be 18500 by sedimentation equilibrium and electrophoresis in sodium dodecyl sulphate. 2. Addition of 2 Ca2+ ions per molecule produced reversible changes in the u.v.-absorption spectrum that are interpreted as arising from conformational changes in the structure of the protein. 3. Cd2+ was almost as effective as Ca2+ in producing the spectral changes. Other bivalent metal ions, particularly Mg2+, were less effective. 4. Binding of Ca2+ by the calcium-binding protein produced an increase in mobility to the anode on electrophoresis in 6m-urea at pH8.6. The Ca2+-saturated form of the protein was more retarded on gel filtration than the Ca2+-free form. 5. In the presence of Ca2+ the calcium-binding protein formed an equimolar complex with the inhibitory protein. This complex was stable in 8m-urea and in the pH range 7.0–8.6. 6. An isotope-dilution method for the measurement of the content of calcium-binding protein in whole muscle is described. In rabbit psoas muscle the ratio of actin monomers to molecules of calcium-binding protein was approx. 7:1. Similar values were obtained for red skeletal and cardiac muscle. 7. Evidence is presented indicating that in the rabbit the inhibitory protein of the troponin complex of red skeletal and cardiac muscles is different from the inhibitory protein of white skeletal muscle.
198 citations
TL;DR: Troponin T either in its isolated form or in the troponin complex was not phosphorylated by bovine protein kinase to any significant extent under the conditions used and had no significant effect on the ability of normal concentrations to confer Ca(2+) sensitivity on the adenosine triphosphatase of densensitized actomyosin.
Abstract: 1. The troponin complex from skeletal muscle contains approximately 1 mol of phosphate/80000g of complex, covalently bound to the troponin T component. 2. On prolonged incubation of the troponin complex or troponin T with phosphorylase kinase the phosphate content of troponin T was increased to approx. 3mol/mol. 3. On prolonged incubation of troponin I with phosphorylase kinase up to 1.6mol of phosphate/mol were incorporated. 4. Phosphorylation of troponin I was greatly inhibited by troponin C owing to the strong interaction between these proteins. Thus in the troponin complex troponin T was the main substrate for phosphorylase kinase. The phosphorylation of isolated troponin T was also inhibited by troponin C. 5. Troponin I was phosphorylated when the troponin complex was incubated with a bovine cardiac 3′:5′-cyclic AMP-dependent protein kinase. Troponin T either in its isolated form or in the troponin complex was not phosphorylated by bovine protein kinase to any significant extent under the conditions used. 6. If the troponin complex was dephosphorylated to 0.2mol/mol, or phosphorylated up to 2.5mol/mol there was no significant effect on the ability of normal concentrations to confer Ca2+ sensitivity on the adenosine triphosphatase of densensitized actomyosin.
TL;DR: In this article, the stability of the three known phases in the Y2O3-Al 2O3 pseudo-binary system has been investigated and an optical and scanning electron microscope study of the associated morphological changes in YAlO3 has been conducted.
Abstract: The stability of the three known phases in the Y2O3-Al2O3 pseudo-binary system has been investigated. YAlO3 (YAP) and Y4Al2O9 (YAM) decompose at elevated temperatures, the products of the reaction being the third compound Y3Al5O12 (YAG) and an unknown phase (designated X). The decomposition is most evident in powders but can also be initiated on the surface of bulk single crystals. X-ray diffraction studies have been performed in an attempt to identify the structure and composition of the unknown phase. The thermal decomposition has been found to be surface controlled and an optical and scanning electron microscope study of the associated morphological changes in YAlO3 indicates that the reaction involves localized surface melting, probably with the loss of oxygen which effectively moves the composition off the binary join.
TL;DR: In this article, the relationship between the initial orientation and grain susceptibilities is discussed quantitatively, for three different strain response models which can be expressed mathematically, demonstrate the characteristic features of the progressive development of the magnetic fabric and emphasize the importance of a knowledge of the strain response model, if measurements of magnetic anisotropy are to be used to measure finite strain.
TL;DR: A more penetrating analysis is needed of the extent to which variation in opinion and personality share a common genetic basis.
Abstract: WHATEVER the current norms might be with regard to public opinion about various issues, and whatever factors contribute to their change with time, attitudes are far from uniform. Eysenck1 has shown how responses to a public opinion questionnaire could be resolved into two main factors: ‘radicalism’ (R) against ‘conservatism’ and ‘toughmindedness’ (T) against ‘tendermindedness’. Individual differences in opinion are, to some degree, the social manifestation of individual differences in personality. Significant covariation has been detected between various measures of extraversion (E) and T. Wilson2 has suggested personality correlates of R. Such relationships, together with available evidence for the genetic determination of personality differences (see, for example, ref. 3), justify a more penetrating analysis of the extent to which variation in opinion and personality share a common genetic basis.
TL;DR: In this paper, a finite strip method is presented for determining the initial buckling stresses of any structure consisting of a series of thin flat isotropic plates rigidly connected together at their longitudinal edges.
Abstract: A finite strip method is presented for determining the initial buckling stresses of any structure consisting of a series of thin flat isotropic plates rigidly connected together at their longitudinal edges. Each plate may be subjected to a combination of longitudinal and transverse compression, longitudinal in-plane bending, and shear, and it is assumed that the buckling mode, of whatever type, is sinusoidal in the longitudinal direction. Due to the presence of shear, the perturbation forces and displacements which occur at the edges of component plates during buckling are out of phase, and this is accounted for by defining their magnitudes in terms of complex quantities. Stiffness matrices relating the amplitudes of these forces and displacements are derived using an approximate method based upon assumed displacement functions across the width of the plate. It is shown how the method can be used to calculate natural frequencies of prismatic structures, and finally an indication of the accuracy of the method is given together with some illustrative results.
TL;DR: It has been shown that white skeletal muscle of rabbit contains an enzyme that transfers the 7 phosphate group from ATP to each of the two :.
TL;DR: Crowding of the dentition and Class 2 dental arch relationship were found to be the main cause of the need for orthodontic treatment and more than 50 per cent of the necessary appliance treatment would be involved in treating Class 2 Division 1 occlusion.
Abstract: Occlusal features and the need for orthodontic treatment are difficult to assess objectively. Methods of assessment which have been devised for public health purposes are different from those which...
TL;DR: A theory to account for the kinetics of coupled-enzyme reactions without assuming that the second reaction follows first-order kinetics is developed and the validity of the theory is confirmed for the assay of glucokinase with glucose 6-phosphate dehydrogenase as coupling enzyme.
Abstract: 1. A theory is developed to account for the kinetics of coupled-enzyme reactions without assuming that the second reaction follows first-order kinetics. 2. A simple procedure is described for applying the theory to the practical design of enzyme assays. 3. The validity of the theory is confirmed for the assay of glucokinase with glucose 6-phosphate dehydrogenase as coupling enzyme. 4. The possibility of extending the theory to three or more coupled reactions is discussed.
TL;DR: In individuals with coronary heart disease, hypertriglyceridaemia and the presence of a pre-beta-lipoprotein band on electrophoresis, no evidence was obtained to suggest that the electrophoretic abnormality was directly due to the increased frequency of Lp(a) reactivity found in such subjects.
TL;DR: In this article, the low growth rate and threshold properties of two pearlitic steels have been evaluated and an increasing effect of load ratio was observed as the threshold was approached, such that control of crack growth passed from ΔK to Kmax.
TL;DR: Application of the procedure to the striated muscle of rabbit has indicated that there are at least three forms of troponin I present in this tissue, each form being specific for the type of muscle from which it is isolated.
TL;DR: In this paper, a two-stage model for structure sensitive crack growth is proposed, where the transition from structure sensitive to structure insensitive can be correlated with the attainment of a critical value of the reverse plastic zone size equal to the α grain size of the microstructure in question.
TL;DR: The basic and neutral fungal stimulants previously reported in anthers were also found in wheat germ, and both materials yielded crystalline preparations of the two active factors on fractionation.
Abstract: The basic and neutral fungal stimulants previously reported in anthers [ 25 ] were also found in wheat germ. Both materials yielded crystalline preparations of the two active factors on fractionation. The basic component was identified by mass spectrometry as choline and the neutral one as betaine. Activities of authentic choline chloride and betaine hydrochloride in the bioassay were recorded as 22 500 and 5600 units/mg respectively. A third minor component was separated from wheat germ extracts but not from anther extracts.
01 Feb 1974-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this paper, the authors proposed a mechanism for the structure sensitive mode of fatigue crack growth in vacua of 1.33 mN m-2, on Ti-6 A1-4V, at growth rates of 10-7 to 10-4 mm/cycle.
Abstract: Fatigue crack propagation studies in vacua of 1.33 mN m-2, on Ti-6 A1-4V, at growth rates of 10-7 to 10-4 mm/cycle have shown that a threshold for growth exists at ‡K values of 6.3 to 7.6 MN m-3/2. The value of the threshold level is microstructure dependent, but growth above this value was structure insensitive according to both growth rates and fracture surface observations. Some slow (≈ 10-8 mm/cycle) crack extension was observed below the threshold values but prolonged cycling reduced the growth rate to a vanishingly small level. Fracture surface observations indicated that growth in this region was microstructure sensitive. Comparison with previously performed air work on the same material showed that while structure insensitive growth rates in vacuum were slower than those in air by a factor of 3 to 4, the low ‡K value structure sensitive rates were slower than the air ones by at least three orders of magnitude. A hypothesis is proposed to explain this in terms of a propagation mechanism for the structure sensitive mode of fatigue crack growth.
TL;DR: It is concluded that at least part of the acceptability of a food is an augmentation of its power to elicit ingestatory reactions which has been established by the contingency of physiological effects of ingested carbohydrate or protein on experiences of that foodstuff’s distinctive sensory qualities.
Abstract: Rat pups come to accept a starch-containing diet and to prefer its flavor or other sensory properties, even when they also have access to the laboratory chow on which their mother is maintained. Protein induces acceptance somewhat more weakly, triglyceride not at all under the conditions used. Nutrient-free material becomes aversive. It is concluded that at least part of the acceptability of a food is an augmentation of its power to elicit ingestatory reactions which has been established by the contingency of physiological effects of ingested carbohydrate or protein on experiences of that foodstuff’s distinctive sensory qualities.
TL;DR: In this paper, the performance of curved-beam, finite element models of circular center line in the solution of circular arch problems is investigated. But the authors focus on the selection of the assumed displacement patterns and the comparative efficiency of some relatively high-order, independently-interpolated models and of previously formula: ed models.
TL;DR: The results were considered as evidence of a hierarchically organised motor program controlling the responses where the various levels are characterised by the speed and extent to which they can be up-dated by incoming information.
TL;DR: It is concluded that the event in inositol lipid metabolism that is affected by acetylcholine stimulation is removal of the phosphorylinositol group from the molecule; this is mediated through muscarinic cholinergic receptors.
Abstract: When rat parotid fragments that had been labelled with 32P in vivo were exposed to high concentrations of acetylcholine, radioactivity was lost from phosphatidylinositol but not from other phospholipids. Simultaneously the concentration of phosphatidylinositol in the tissue decreased. If previously unlabelled tissue was incubated with 32Pi an increase in incorporation of radioactivity into phosphatidylinositol was observed during this decrease in concentration. The effects of acetylcholine were blocked by atropine, but not by tubocurarine. The response to acetylcholine was rapid, with up to one-third of the tissue's phosphatidylinositol disappearing within 5min. Similar effects were evoked by stimulation with methacholine and by high concentrations of tetramethylammonium ion; these responses were also atropine-sensitive and tubocurarine-insensitive. It is concluded that the event in inositol lipid metabolism that is affected by acetylcholine stimulation is removal of the phosphorylinositol group from the molecule; this is mediated through muscarinic cholinergic receptors. This is followed by a compensatory increase in the rate of synthesis of phosphatidylinositol, which has been described in detail in the past. These observations are compared with those of previous workers and are discussed in relation to the existing hypotheses relating to the significance of stimulus-provoked phosphatidylinositol turnover.
TL;DR: Results from this study have provided new information Regarding the functioning of the genes coding for the Leloir pathway enzymes in man1, and have revealed a relatively close and potentially useful linkage between the genes for galactokinase and for thymidine kinase.
Abstract: PROGRESS in somatic cell genetics now allows more rapid and precise localisation of genes within the human genome. A large number of mouse × human hybrid cell lines are available, permitting the investigator to choose, for phenotype assay, lines with a particular reduced human chromosome complement. An increasingly large number of hybrid lines carrying rearranged chromosomes are also becoming available for regional localisation studies. We have used such hybrid cell lines to assign a gene coding for galactokinase (EC 2.7.1.6) to human chromosome 17 and to further localise the gene to band 21–22 on the long arm of the chromosome. Results from this study have provided new information Regarding the functioning of the genes coding for the Leloir pathway enzymes in man1, and have revealed a relatively close and potentially useful linkage between the genes for galactokinase and for thymidine kinase (EC 2.7.1.21).
TL;DR: In this paper, the He(I) photoelectron spectra of the isoelectronic series Fe(CO)2(NO)2, Co( CO)3NO and Ni(CO4) were reported and interpreted by means of ab initio SCF-MO calculations.
Abstract: The He(I) photoelectron spectra of the isoelectronic series Fe(CO)2(NO)2, Co(CO)3NO and Ni(CO)4 are reported and interpreted by means of ab initio SCF-MO calculations. For the nitrosyl complexes it is found that ionization potentials calculated assuming Koopmans' theorem are seriously in error due to the considerably greater orbital relaxation accompanying ionization from metal than from NO valence orbitals. When such allowance is made for orbital relaxation by performing restricted Hartree-Fock (RHF) calculations on the ionic states, the experimental spectra are accurately reproduced and the observed similarity of the spectra of all three molecules is explained.