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Notes: A definitive set of the Los Alamos Hugoniot data for iron in a pressure regime extending to 442 GPa is given. Earlier standards data, obtained using conventional explosive systems, were thoroughly reprocessed. All original film records were reread. On the basis of more recent experiment and theory, some data were culled because the experimental designs were found to be insufficiently conservative. The analysis was also modified to take into account preheating of the explosively driven flyer plates. Minor clerical errors in transcription of measurements were corrected. An improved algorithm for the flash-gap time correction was incorporated. Higher-pressure data were obtained using a conventional 13-pin target assembly on a two-stage light gas gun. Several polynomial representations of the data are given. A linear fit to the data (Us=3.935+1.578 Up, where the shock velocity Us and the particle velocity Up are in km/s) has a root-mean-square misfit of 62 m/s. The quadratic fit (Us=3.691+1.788 Up−0.038 Up2) has a root-mean-square misfit of 39 m/s. © 2000 American Institute of Physics.

Notes: Economic models have suggested that population Helicobacter pylori screening and treatment may be a cost-effective method of reducing mortality from gastric cancer. These models are conservative as they do not consider that the programme may reduce health service peptic ulcer and other dyspepsia costs. We have evaluated the economic impact of population H. pylori screening and treatment over 2 years in a randomized controlled trial and have incorporated the results into an economic model exploring the impact of H. pylori eradication on peptic ulcer disease and gastric cancer.〈section xml:id="abs1-2"〉〈title type="main"〉Methods:Subjects between the ages of 40 and 49 years were randomly invited to attend their local primary care centre. H. pylori status was evaluated by 13C-urea breath test and infected individuals were randomized to receive omeprazole, 20 mg b.d., clarithromycin, 250 mg b.d., and tinidazole, 500 mg b.d., for 7 days or identical placebos. Economic data on health service costs for dyspepsia were obtained from a primary care note review for the 2 years following randomization. These data were incorporated into a Markov model comparing population H. pylori screening and treatment with no intervention.〈section xml:id="abs1-3"〉〈title type="main"〉Results:A total of 2329 of 8407 subjects were H. pylori positive: 1161 were randomized to receive eradication therapy and 1163 to receive placebo. The cost difference favoured the intervention group 2 years after randomization, but this did not reach statistical significance (£11.42 per subject cost saving; 95% confidence interval, £30.04 to – £7.19; P=0.23). Analysis by gender suggested a statistically significant dyspepsia cost saving in men (£27.17 per subject; 95% confidence interval, £50.01 to £4.32; P=0.02), with no benefit in women (– £4.46 per subject; 95% confidence interval, – £33.85 to £24.93). Modelling of these data suggested that population H. pylori screening and treatment for 1 000 000 45-year-olds would save over £6 000 000 and 1300 years of life. The programme would cost £14 200 per life year saved if the health service dyspepsia cost savings were the lower limit of the 95% confidence intervals and H. pylori eradication had only a 10% efficacy in reducing mortality from distal gastric cancer and peptic ulcer disease.〈section xml:id="abs1-4"〉〈title type="main"〉Conclusions:Modelling suggests that population H. pylori screening and treatment are likely to be cost-effective and could be the first cost-neutral screening programme. This provides a further mandate for clinical trials to evaluate the efficacy of population H. pylori screening and treatment in preventing mortality from gastric cancer and peptic ulcer disease.

Notes: The quality of the pseudopotential approximation has been tested thoroughly by calculating spectroscopic properties of the gold atom and ground state AuH for eight different effective core potentials using Hartree–Fock, second-order Møller–Plesset and coupled cluster methods. The pseudopotential valence basis set {cursive-phi}v for Au was chosen to be identical for all pseudopotentials, a subset of the all-electron basis set {cursive-phi}v⊂{cursive-phi}AE, and the condition was applied that all sets are of near basis set limit quality. The pseudopotential results are compared with data obtained from nonrelativistic, scalar relativistic Douglas–Kroll and fully relativistic four-component all-electron calculations. The variation between the results obtained for all valence electron small-core pseudopotentials and all electron Douglas–Kroll calculations is found to be small (for the Stuttgart pseudopotential Δre=0.001 Å, ΔDe=0.03 eV, Δωe=9 cm−1, Δμe=0.04 D). Sizable differences to all electron results are only found for the 11 valence electron large-core pseudopotentials. The effects of the basis set superposition error on spectroscopic constants were investigated. Calculated coupled cluster electron affinities and ionization potentials for gold and spectroscopic properties for AuH were found to be in excellent agreement with available experimental data. The variation between the different small-core pseudopotentials for one particular spectroscopic property is shown to be less than the error due to the incompleteness of electron correlation procedure or the basis set and approximately of the same size as the basis set superposition error. The results show that scalar relativistic effects for valence properties are perfectly described by the pseudopotential approximation. © 2000 American Institute of Physics.

Notes: The suprachiasmatic nuclei (SCN) of the hypothalamus house the main circadian pacemaker in mammals. Vasoactive intestinal polypeptide (VIP) is the most abundant neuropeptide in the SCN and has been shown to phase-shift the electrical activity rhythm of SCN cells in vitro. However, the effects of VIP on the cellular activity of rat SCN neurones are unknown. In this study, we examined the acute effects of VIP on the extracellularly recorded spontaneous firing rate of SCN neurones in an in-vitro hypothalamic slice preparation. Furthermore, with the use of receptor-selective agonists and antagonists, we determined which receptors might mediate the effects of VIP in the SCN. Approximately 50% of cells responded to VIP; the main type of response was suppression in firing rate, although a few cells were activated. Suppression responses to VIP were mimicked by the VPAC2 receptor agonist Ro 25-1553 and blocked by the selective VPAC2 receptor antagonist PG 99-465. The PAC1 receptor agonist maxadilan evoked responses from 40% of SCN cells, and activations to this agonist were not altered by PG 99-465. Responses to VIP were not blocked by antagonists to ionotropic glutamate receptors, but the duration of suppression was modulated by the GABAA receptor antagonist bicuculline. Our data indicate that VIP alters the electrical activity of rat SCN neurones in vitro, via both VPAC2 and PAC1 receptors.

Notes: The biotrophic fungus Puccinia striiformis f.sp. tritici, a basidiomycete that causes yellow rust on wheat, is spread by wind-dispersed spores. Analysis of amplified fragment length polymorphism (AFLP) variation showed that the fungus frequently migrates between the UK, Germany, France and Denmark. There is no biological evidence for sexual or parasexual reproduction under natural conditions, and this was supported by the lack of recombination, as revealed by AFLP, over the time and area represented by the samples in this study. A phylogeographic analysis revealed that there was effectively a single, clonal population in the four countries, up to 1700 km apart, consistent with a ‘continent-island’ model in which Denmark is the recipient of migrants from other countries. In five cases, specific pathogen clones were dispersed between the UK and Denmark, and on at least two recent occasions clones were also spread from the UK to Germany and France, causing outbreaks of yellow rust on wheat cultivars that were previously resistant to the disease in these countries. The agronomic consequences of migration were enhanced because of the limited genetic diversity for yellow rust resistance in wheat cultivars in the area. These results demonstrate that long-distance migration of pathogen clones, coupled with low diversity in the host species, may cause previously useful resistance genes to become ineffective for disease control on a continental scale.

Notes: Yellowtail flounder Pleuronectes ferrugineus (Storer) have been identified as a potential species for coldwater aquaculture along the north-east coast of Canada. It has been shown that increased photoperiods improve growth and survival during the larval stage of this species. We conducted two experiments to determine the effect of photoperiod on the growth and survival of juveniles. The first experiment compared growth and survival under 24-, 18- and 12-h lighting per day with a restricted food ration. The second experiment compared growth and survival rates under the above photoperiods and ambient lighting with fish being fed to satiation. No significant differences in growth or survival were found in juveniles under the different photoperiods in either experiment.

Notes: Mucosal mast cells (MMC) play a central role in gut hypersensitivities and inflammation. They are morphologically, biochemically and functionally distinct from their connective tissue counterparts. Massive hyperplasia of MMC occurs 7–10 days after intestinal infection with nematodes but it has never been possible to replicate this phenomenon in vitro.〈section xml:id="abs1-2"〉〈title type="main"〉Objective(1) To determine whether mouse bone marrow-derived mast cells (mBMMC) grown in the presence of transforming growth factor (TGF)-β1 could develop over the same time frame (7–10 days) as MMC in parasitized mice. (2) To compare the early expression of surface receptors (integrins αE and β7, c-kit and FcεR) with that of the MMC-specific granule chymase mouse mast cell protease-1 (mMCP-1).〈section xml:id="abs1-3"〉〈title type="main"〉MethodsMouse bone marrow cells were cultured in the presence of IL-9, IL-3 and Stem Cell Factor (SCF) with or without TGF-β1. mBMMC were quantified after toluidine blue or Leishmans' staining. Expression of MMC-specific mouse mast cell proteases was analysed by ELISA, immunohistochemistry and RT-PCR. Surface antigen expression was characterized by flow cytometry and confocal microscopy.〈section xml:id="abs1-4"〉〈title type="main"〉ResultsTGF-β1 promotes the development of abundant MMC-like mBMMC from bone marrow progenitor cells with kinetics, which closely parallel that seen in vivo. mRNA transcripts encoding mMCP-1 and -2 are readily detectable by day 4 ex vivo in cultures grown in the presence of TGF-β1. Between 30 and 40% and 75–90% of the cells in these cultures on days 4 and 7, respectively, have typical mast cell morphology, are c-kit+, FcεR+, integrin αEβ7+, and express and secrete abundant mMCP-1. The integrin αE subunit is coexpressed with mMCP-1.〈section xml:id="abs1-5"〉〈title type="main"〉ConclusionThe kinetics of mMCP-1+/αE+ mBMMC development, regulated by TGF-β1, are consistent with that seen in vivo in the parasitized intestine. The normally down-regulatory functions of TGF-β1 in haematopoiesis are superseded in this culture system by its ability to promote the early expression of αE and mMCP-1.