Search Results - (Author, Cooperation:P. Hunt)

2018-10-10

Nature Publishing Group (NPG)

2045-2322

Natural Sciences in General

2011-04-19

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

3' Untranslated Regions/genetics ; Alleles ; Base Sequence ; Cell Line ; *Gene Expression Regulation/genetics/immunology ; Genes, Reporter/genetics ; HIV/*immunology ; HIV Infections/*genetics/*immunology/therapy ; HLA-C Antigens/*genetics ; Humans ; MicroRNAs/*genetics ; Polymorphism, Single Nucleotide/genetics ; Viral Load

2018-02-10

American Physical Society (APS)

0556-2813

1089-490X

Physics

Nuclear Structure

2012-04-17

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Benzothiazoles/pharmacology/*therapeutic use ; Cell Line, Tumor ; DNA Mutational Analysis ; Drug Resistance, Neoplasm/genetics ; Humans ; Leukemia, Myeloid, Acute/*drug therapy/*genetics/metabolism ; Models, Molecular ; Molecular Structure ; *Molecular Targeted Therapy ; Mutation/*genetics ; Phenylurea Compounds/pharmacology/*therapeutic use ; Protein Binding ; Protein Structure, Tertiary/genetics ; Recurrence ; Reproducibility of Results ; fms-Like Tyrosine Kinase 3/*antagonists & inhibitors/*genetics/metabolism

2018-02-21

The American Association of Immunologists (AAI)

0022-1767

1550-6606

Medicine

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

Schlögl's criterion for equistability of two stable stationary states of an inhomogeneous chemical kinetic system is valid only for single-variable cases dependent along a single spatial coordinate. We test the thermodynamic theory, developed in the preceding article for multivariable systems, in one dimension by comparison with calculations based on the deterministic reaction-diffusion equation for a cubic Schlögl model (single variable). This reaction-diffusion system is equivalent to a coupled multivariable system. The prediction of the thermodynamic theory of equistability approaches Schlögl's result as the length of the system increases. We also test the theory for an optically bistable (ZnSe) system which has been studied experimentally; in this system, temperature is the variable, and there is transport by thermal conduction. Again, we find that the prediction of the multivariable thermodynamic theory approaches the result from the deterministic kinetic equation as the length of the system increases. Further, the single-variable thermodynamic theory of relative stability of homogeneous steady states agrees with experiments and with the prediction of the deterministic equation.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The thermodynamic and stochastic theory of chemical systems far from equilibrium is extended to reactions in inhomogeneous system for both single and multiple intermediates, with multiple stationary states coupled with linear diffusion. The theory is applied to the two variable Selkov model coupled with diffusion, in particular to the issue of relative stability of two stable homogeneous stationary states as tested in a possible inhomogeneous experimental configuration. The thermodynamic theory predicts equistability of such states when the excess work from one stationary state to the stable inhomogeneous concentration profile equals the excess work from the other stable stationary state. The predictions of the theory on the conditions for relative stability are consistent with solutions of the deterministic reaction-diffusion equations. In the following article we apply the theory again to the issue of relative stability for single-variable systems, and make comparison with numerical solutions of the reaction-diffusion equations for the Schlögl model, and with experiments on an optically bistable system where the kinetic variable is temperature and the transport mechanism is thermal conduction.

Electronic Resource

1365-2133

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

SUMMARY.— The vasoconstrictor test of McKenzie and Stoughton (1962) has been adapted for studying the release of betamethasone 17-valerate and 21-desoxy betamethasone 17-propionate from ointments. Vasoconstriction on the skin of volunteers was assessed quantally by noting presence or absence of vasoconstriction or quantitatively by measuring diameters of vasoconstricted areas. The quantitative method employs corticosteroid doses higher than those used in the quantal method of McKenzie and Stoughton. The vasoconstrictor potencies of 3 betamethasone derivatives have been compared using the quantitative method in order to confirm its validity. The quantitative method was used for comparing various ointment bases with betamethasone 17-valerate or 21-desoxy betamethasone 17-propionate. High relative potencies were obtained by the inclusion of propylene glycol in the ointments. Ointments containing betamethasone 17-valerate and varying amounts of hydrogenated lanolin were compared.The quantitative and quantal methods showed that relative vasoconstrictor potency increased or diminished respectively with increased concentration of hydrogenated lanolin. The effect of hydrogenated lanolin in vehicles on the release of betamethasone 17-valerate was studied using two in vitro model systems and the results are discussed in relation to those of the in vivo experiments.

Electronic Resource

1095-8649

Blackwell Publishing Journal Backfiles 1879-2005

Biology

The results of the application of Schnabel (Chapman modification), Schumacher & Eschmeyer, Fisher & Ford, and Jolly capture-recapture techniques on the Barbus barbus (L.) population in four areas of the middle Severn are compared. The survival of tagged fish varied in different areas and fish released in some time periods were less vulnerable to recapture than fish released from other samples. It is suggested that the shoaling behaviour of Barbus barbus resulted in non-random mixing of marked fish. The average population size of Barbus barbus greater than 18 cm in length in each of the four sections for the total period of investigation gave population densities ranging from 0.024/m2 to 0.202/m2.

Electronic Resource

1095-8649

Blackwell Publishing Journal Backfiles 1879-2005

Biology

The contents of the stomachs of 38 rainbow trout stocked in Llyn Alaw, Anglesey, in August 1969 and caught between October 1969 and February 1970 were analysed. The fish were actively feeding on the bottom fauna throughout the winter and 21 of the stomachs were full or distended. The mean volume of the contents of the stomachs was 2–8 times greater than that of the contents of stomachs of similarly sized brown trout caught at the same time.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The eikonal approximation (instanton technique) is applied to the problem of large fluctuations of the number of species in spatially homogeneous chemical reactions with the probability density distribution described by a master equation. For both autocatalytic and nonautocatalytic reactions, the analysis of the distribution about a stable stationary state and of the transitions between coexisting stable states comes, to logarithmic accuracy, to the analysis of Hamiltonian dynamics of an auxiliary dynamical system. The latter can be done explicitly in a few cases, including one-species systems, systems with detailed balance, and systems close to the bifurcation points where the number of the stable states changes. In the last case, the fluctuations display universal features, and, for saddle-node bifurcation points, the logarithm of the probability of escape from the metastable state (per unit time) is proportional to the distance to the bifurcation point (in the parameter space) raised to the power 3/2. We compare the eikonal approximation for the stationary distribution of a master equation to Monte Carlo numerical solutions for two chemical two-variable systems with multiple stationary states, where none of the cited restrictions exists. For one of the systems in the pattern of optimal paths we observe caustics emanating from the saddle point.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The adaptive multigrid technique in the finite element method of the solution of partial differential equations is examined in the context of model problems in atom–atom and collinear atom–diatom collisions. For the problem leading to scattering along an L-shaped region, it yields accurate results for regions of energy far from threshold for excitation of a new channel without inclusion of virtual states. Close to threshold, the cusp-like structure of the transition probability (vs energy) and the time delay associated with the onset of a resonance are recovered only by inclusion of the new (closed) channel in the finite element solution. For atom–diatom collinear collisions, use of an orthogonal coordinate system facilitates discretization and adds no extra labor in the finite element method, compared to the usual mass-weighted system. In such collisions, where the threshold behavior of the transition probability resembles the presence of a bound-state resonance below the threshold, the no-virtual-state solution is shifted in energy relative to the converged one-virtual-state solution. Under certain circumstances, transition probabilities from the former solution are found to deviate substantially from those determined from the latter in energy regions well below threshold. The multigrid method of solution of the finite element equation is found to be accurate provided a sufficiently fine grid is employed for the coarsest level of the multigrid adaptive solution process. However, for the problems studied, when the solution obtained from the coarsest grid does not yield a sufficiently accurate interpolated initial approximation for the relaxation method of solution of the finer grid levels, this method was found to converge to erroneous solutions. In future work, techniques examined herein will be applied to molecular scattering problems involving collisional dissociation.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Triazolam 0.25 mg, diazepam 10 mg and placebo were compared in a randomized double-blind trial of oral premedication in 90 patients undergoing minor gynaecological surgery. Both triazolam and diazepam produced a significant sedative effect as measured by patient serf assessment linear analogue scales but only diazepam was more anxiolytic than placebo. Psychomotor performance assessed by the letter-search test at 3 and 6 hours after awakening showed a decrement in performance in patients receiving triazolam at 3 hours compared with the two other groups. Triazolam was shown to have a pronounced amnesic effect and whilst it might be used for premedication, its lack of anxiolysis coupled with a significant impairment of psychomotor performance at 3 hours after awakening, render the drug unsuitable for premedication in the short stay patient.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The effects of pancuronium and vecuronium on the lower oesophageal sphincter pressure were studied in 24 healthy patients anaesthetised with 0.5% halothane in nitrous oxide and oxygen. Following pancuronium 0.1 mg/kg intravenously, there was a significant increase in barrier pressure from a control value of 2.0 (SEM 0.14) kPa to 3.0 (SEM 0.27) kPa 1 minute after injection (p 〈 0.05). This increase was sustained throughout the 15 minute period of recording and was accompanied by a significant increase in heart rate (p 〈 0.001). Following administration of vecuronium 0.1 mg/kg intravenously there was an initial modest, though not significant increase in barrier pressure. This increase was significant (p 〈 0.05) at 15 minutes. There were no cardiovascular changes following vecuronium.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Reports and guidelines concerning intensive care practice have been issued recently. However, the introduction of such centrally issued recommendations may be difficult because of marked heterogeneity between intensive care units. This study examined the facilities (number of beds, consultant sessions, nursing establishment), annual workload (number and types of patients admitted) and outcome (intensive care unit mortality) in the (old) Anglia Region. There were significant differences in the distribution of patients' ages, severities of illness, diagnoses, durations of admission and outcomes. Such heterogeneity may make multicentre trials more difficult to conduct and create problems when uniform measures designed to improve intensive care services are being planned.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1095-8649

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Scales from 7071 barbel from the River Severn were used for age and growth determinations. The scales showed clear annual checks which were laid in May when most fish spawned. Scale structure and length frequency distributions showed an almost total absence of 1968 year class barbel. Growth was significantly faster in some sections of the sampling area than in others. Back-calculated growth analysis showed a systematic decrease in length for each age for females and males in the 1961 to 1967 year classes. Females grew significantly faster than males after four years of age and reached greater ultimate size. There was a preponderance of males between the ages of III and VII and a dominance of females in older age groups. The overall sex ratio of males to females was 2–41: 1. A distinct seasonal growth pattern was shown.

Electronic Resource

1095-8649

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Five hundred and thirty one of a total of 3122 tagged Barbus barbus (L.) in the middle Severn were recaptured using electric fishing and angling. Ninety two barbel were recaught downstream of the site of tagging, 152 upstream and 287 did not move. Electric fishing was selective for home recaptures. The barbel population was divisible into mobile and static components; 86% remained within 5 km, the remainder wandering more widely up to a maximum of 34 km from their site of tagging. Movement seemed to be dependent on size of the fish.

Electronic Resource

1095-8649

Blackwell Publishing Journal Backfiles 1879-2005

Biology

The results of the analysis of the contents of 274 brown trout stomachs taken over a period of one year from Llyn Alaw, in Anglesey, North Wales, are described. The annual composition and seasonal changes of the diet were determined using number, volume and occurrence methods. The bottom fauna is classified according to accessibility to the trout as food and the utilization and apparent selection of the fauna by the trout is discussed. Food in relation to trout size is considered in detail.

Electronic Resource

1095-8649

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Water level fluctuations of up to 5.5 m in the newly constructed reservoir, Llyn Celyn, were shown to result in a uniformly barren littoral zone in which Lumbriculidae, Pisidium sp. and Chironomidae were the only animals to occur in significant numbers throughout the year. Other groups of animals were unable to survive the big fluctuations in water level and this in turn affected the food and growth of trout in the environment.

Electronic Resource