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Farley JH, Williams AJ, Clear NP, Davies CR, Nicol SJ. Age estimation and validation for South Pacific albacore Thunnus alalunga. JOURNAL OF FISH BIOLOGY 2013; 82:1523-1544. [PMID: 23639152 DOI: 10.1111/jfb.12077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 01/28/2013] [Indexed: 06/02/2023]
Abstract
Validated estimates of age are presented for albacore Thunnus alalunga, sampled from a large part of the south-western Pacific Ocean, based on counts of annual opaque growth zones from transverse sections of otoliths. Counts of daily increments were used to estimate the location of the first opaque growth zone, which was completed before the first assumed birthday. The periodicity of opaque zones was estimated by marginal increment analysis and an oxytetracycline mark-recapture experiment. Both validation methods indicated that opaque zones formed over the austral summer and were completed by autumn to winter (April to August). The direct comparison of age estimates obtained from otoliths and dorsal-fin spines of the same fish indicated bias, which was assumed to be due to poor increment clarity and resorption of early growth zones in spines, resulting in imprecise age estimates. As such, age estimates from otoliths are considered to be more accurate than those from spines for T. alalunga. This is consistent with results for a growing number of tropical and temperate tuna Thunnini species. It is recommend that validated counts of annual growth zones from sectioned otoliths is used as the preferred method for estimating age-based parameters for assessment and management advice for these important stocks.
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Currey LM, Williams AJ, Mapstone BD, Davies CR, Carlos G, Welch DJ, Simpfendorfer CA, Ballagh AC, Penny AL, Grandcourt EM, Mapleston A, Wiebkin AS, Bean K. Comparative biology of tropical Lethrinus species (Lethrinidae): challenges for multi-species management. JOURNAL OF FISH BIOLOGY 2013; 82:764-788. [PMID: 23464543 DOI: 10.1111/jfb.3495] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Life-history characteristics of six tropical Lethrinus species sampled from the Great Barrier Reef World Heritage Area were compared. Two species groups were identified based on fork length (LF ): large species with maximum LF > 640 mm (longface emperor Lethrinus olivaceus, yellowlip emperor Lethrinus xanthochilus and spangled emperor Lethrinus nebulosus) and small species with maximum LF < 480 mm (Pacific yellowtail emperor Lethrinus atkinsoni, pink ear emperor Lethrinus lentjan and ornate emperor Lethrinus ornatus). Lifespan was not correlated with LF . Early growth for all species was rapid and similar during the first few years of life, but coefficients of the von Bertalanffy growth function varied considerably among species. Growth also differed between sexes for L. atkinsoni. Reproductive characteristics varied among species, with peak periods of spawning occurring in November to December for L. atkinsoni, July to August for L. nebulous, September to October for L. olivaceus and a protracted season for L. lentjan, although fewer samples were available for the last two species. Sex-specific LF and age distributions and gonad histology of L. lentjan were suggestive of a functional protogynous reproductive pattern, as observed in other lethrinids. Gonad histology indicated non-functional protogynous hermaphroditism for L. atkinsoni and L. nebulosus. The diversity of life histories among these closely related species emphasizes the difficulty in devising single management strategies appropriate for multi-species fisheries and illustrates the importance of understanding species-specific life histories to infer responses to exploitation.
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Werkheiser JL, Sydserff S, Hubbs SJ, Ding M, Eisman MS, Perry D, Williams AJ, Smith JS, Mrzljak L, Maier DL. Ultra-low exposure to α-7 nicotinic acetylcholine receptor partial agonists elicits an improvement in cognition that corresponds with an increase in α-7 receptor expression in rodents: implications for low dose clinical efficacy. Neuroscience 2011; 186:76-87. [PMID: 21550383 DOI: 10.1016/j.neuroscience.2011.04.033] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 04/11/2011] [Accepted: 04/12/2011] [Indexed: 11/16/2022]
Abstract
Αlpha-7 neuronal nicotinic receptors (NNRs) are considered targets for cognitive enhancement in schizophrenia and Alzheimer's disease. AZD0328 is an alpha-7 NNR partial agonist that enhances cognition in rodents and nonhuman primates at sub-microgram to microgram doses. We hypothesized that increased expression of the alpha-7 receptor contributes to this beneficial activity at low doses and tested this by examining the effect of AZD0328 using in vivo and ex vivo binding, RT-PCR and cognitive function in rodents. AZD0328 (0.00178 mg/kg) was subcutaneously administered to mice 4, 24, 48 and 72 hours prior to testing in novel object recognition and produced a significant increase in cognition at 4, 24 and 48 h post-dosing. In vivo binding was examined in rat brain using [(3)H]AZ11637326 and there was a dose-dependent reduction in receptor binding at higher doses of AZD0328 (0.001-3 mg/kg), and a second alpha-7 partial agonist, SSR180711 (0.01-30 mg/kg). Lower doses of both compounds (0.0001 mg/kg) produced a significant increase in binding of [(3)H]AZ11637326. Ex vivo binding using [(125)I]-α-bungarotoxin, showed a significant increase in receptor number (B(max.)) in the frontal cortex or hippocampus with no significant effect on receptor affinity (K(d)) 2 h post administration of AZD0328. [(3)H]AZ11637326 administered 1.5 h following AZD0328 produced a significant increase in specific binding in rat brain regions. We found that the effect on receptor number was long-lasting, with [(125)I]-α-bungarotoxin binding increased in rats given AZD0328 for 2-48 h, but this was not accompanied by increased mRNA synthesis. SSR180711 produced a similar increase in B(max.) and specific binding with no effect on K(d). Therefore, trace dose of alpha-7 partial agonists has rapid onset and produces a profound, sustained effect on novel object recognition in mice that corresponds by dose to an increase in receptor number in rat brain. These findings provide an explanation for the acute and sustained benefit of alpha-7 receptor activation in working memory in nonhuman primates and guidance for drug development initiatives and treatment regimens for nicotinic partial agonists.
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Wassilak S, Pate MA, Wannemuehler K, Jenks J, Burns C, Chenoweth P, Abanida EA, Adu F, Baba M, Gasasira A, Iber J, Mkanda P, Williams AJ, Shaw J, Pallansch M, Kew O. Outbreak of type 2 vaccine-derived poliovirus in Nigeria: emergence and widespread circulation in an underimmunized population. J Infect Dis 2011; 203:898-909. [PMID: 21402542 PMCID: PMC3068031 DOI: 10.1093/infdis/jiq140] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Accepted: 10/22/2010] [Indexed: 11/25/2022] Open
Abstract
Wild poliovirus has remained endemic in northern Nigeria because of low coverage achieved in the routine immunization program and in supplementary immunization activities (SIAs). An outbreak of infection involving 315 cases of type 2 circulating vaccine-derived poliovirus (cVDPV2; >1% divergent from Sabin 2) occurred during July 2005-June 2010, a period when 23 of 34 SIAs used monovalent or bivalent oral poliovirus vaccine (OPV) lacking Sabin 2. In addition, 21 "pre-VDPV2" (0.5%-1.0% divergent) cases occurred during this period. Both cVDPV and pre-VDPV cases were clinically indistinguishable from cases due to wild poliovirus. The monthly incidence of cases increased sharply in early 2009, as more children aged without trivalent OPV SIAs. Cumulative state incidence of pre-VDPV2/cVDPV2 was correlated with low childhood immunization against poliovirus type 2 assessed by various means. Strengthened routine immunization programs in countries with suboptimal coverage and balanced use of OPV formulations in SIAs are necessary to minimize risks of VDPV emergence and circulation.
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Lee KK, Suh E, Peisch J, McGlone A, Mistry A, Murphy P, Williams AJ, Davidson AC, Hart N. S67 Phenotypic differences between obese patients with eucapnic and hypercapnic sleep-disordered breathing (SDB). Thorax 2010. [DOI: 10.1136/thx.2010.150938.18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Murphy P, Dillon R, Williams AJ, Howard J, Hart N. S17 A pilot study of the prevalence of sleep disordered breathing (SDB) and nocturnal hypoxia in symptomatic adults with Sickle Cell Disease (SCD) and its relationship with disease severity. Thorax 2010. [DOI: 10.1136/thx.2010.150912.17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Williams AJ, Pitcher A, Thomas P, Baker R. P127 Does it matter how they breathe?--Perceptions in COPD patients when adopting different routes of breathing. Thorax 2010. [DOI: 10.1136/thx.2010.150987.28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Murphy P, Davidson AC, Williams AJ, Moxham J, Simonds A, Hind M, Polkey MI, Hart N. S65 Interim data from a randomised controlled trial of average volume-assured pressure support (AVAPS) versus spontaneous-timed (ST) pressure support in Obesity Hypoventilation Syndrome (OHS). Thorax 2010. [DOI: 10.1136/thx.2010.150938.16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Vinall AJ, Williams AJ, Currie VE, Van Esch A, Huyskens D. Practical guidelines for routine intensity-modulated radiotherapy verification: pre-treatment verification with portal dosimetry and treatment verification with in vivo dosimetry. Br J Radiol 2010; 83:949-57. [PMID: 20965905 PMCID: PMC3473728 DOI: 10.1259/bjr/31573847] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 07/22/2009] [Accepted: 10/29/2009] [Indexed: 11/05/2022] Open
Abstract
The purpose of this work is to provide guidelines for the routine use of portal dosimetry and in vivo diode measurements to verify intensity-modulated radiotherapy (IMRT) treatments. To achieve tolerance levels that are sensitive enough to intercept problems, both the portal dosimetry and the in vivo procedure must be optimised. Portal dosimetry was improved by the introduction of an optimised two-dimensional (2D) profile correction, which also accounted for the effect of backscatter from the R-arm. The scaled score, indicating the fraction of points not meeting the desired gamma evaluation criteria within the field opening, was determined as the parameter of interest. Using gamma criteria of a 3% dose difference and 3 mm distance to agreement, a "scaled score" threshold value of 1.5% was chosen to indicate excessive tongue and groove and other problems. The pre-treatment portal dosimetry quality assurance (QA) does not encompass verification of the patient dose calculation or position, and so it is complemented by in vivo diode measurements. Diode positioning is crucial in IMRT, and so we describe a method for diode positioning at any suitable point. We achieved 95% of IMRT field measurements within ±5% and 99% within ±8%, with improved accuracy being achieved over time owing to better positioning. Although the careful preparation and setup of the diode measurements can be time-consuming, this is compensated for by the time efficiency of the optimised procedure. Both methods are now easily absorbed into the routine work of the department.
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Lett WR, Williams AJ, Poole ME. The Achievement Drive and Ego Strength of Highly Creative Adolescents. THE JOURNAL OF PSYCHOLOGY 2010. [DOI: 10.1080/00223980.1979.9923497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Owen JC, Moore FR, Williams AJ, Ward MP, Beveroth TA, Miller EA, Wilson LC, Morley VJ, Abbey-Lee RN, Veeneman BA, DeRussy BM, McWhorter MS, Garvin MC. Test of recrudescence hypothesis for overwintering of West Nile virus in gray catbirds. JOURNAL OF MEDICAL ENTOMOLOGY 2010; 47:451-457. [PMID: 20496593 DOI: 10.1603/me09035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
West Nile virus is a pathogen of concern for both human and wildlife health. Although many aspects of the ecology of West Nile virus are well understood, the mechanisms by which this and similar mosquito-borne viruses overwinter and become reinitiated each spring in temperate regions is not known. A thorough understanding of this mechanism is crucial to risk assessment and development of control strategies. One of the hypotheses to explain the mechanism by which this virus persists from year to year is the spring recrudescence of latent virus in avian reservoir hosts. Stress-related immunosuppression is implicated in the recrudescence of latent viruses in birds. We tested the spring recrudescence hypothesis in a controlled laboratory experiment using hatching-year gray catbirds (Dumatella carolinensis) captured in northern Ohio (July-August 2006). Catbirds (n = 60) were experimentally infected (September 2006) and later examined for the effects of immunosuppression through exogenous hormones and artificially induced migratory disposition. We found no effect of either testosterone or migratory behavior on infection status in any of the treatment birds. Moreover, we detected no viral RNA in the kidney, spleen, brain, or liver upon necropsy at 24 wk postinfection.
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Groves ND, Humphreys HW, Williams AJ, Jones A. Effect of informational internet web pages on patients' decision-making: randomised controlled trial regarding choice of spinal or general anaesthesia for orthopaedic surgery. Anaesthesia 2010; 65:277-82. [PMID: 20336817 DOI: 10.1111/j.1365-2044.2009.06211.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
This study explored whether patients' preference for particular types of anaesthesia could be influenced pre-operatively by giving them the addresses of various relevant websites. Patients at an orthopaedic pre-assessment education clinic completed a questionnaire, which included a short multiple-choice general knowledge quiz about anaesthesia, and also questioned them as to their choice of anaesthesia (general or neuraxial). Patients were randomly assigned to intervention or control groups. Intervention group members were given the addresses of three relevant anaesthesia and health related websites to access at home. All patients were asked to complete the questionnaires on a second occasion, before surgery. Initially, most patients stated a preference for general anaesthesia. Subsequently, the intervention group altered their preference towards neuraxial anaesthesia compared to the control group (p < or = 0.0001). The increase in median (IQR [range]) anaesthesia knowledge test score was greater in the intervention group (from 10.0 (9.0-12.0 [5.0-14.0]) to 13.0 (11.0-14.0 [6.0-14.0])) than in the control group (from 10.0 (9.0-11.5 [3.0-13.0]) to 11.0 (9.0-12.0 [4.0-14.0]); p = 0.0068).
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Crawford RJM, Ryan PG, Williams AJ. Seabird consumption and production in the Benguela and Western Agulhas ecosystems. ACTA ACUST UNITED AC 2010. [DOI: 10.2989/025776191784287709] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Jarad NA, Sequeiros IM, Hester K, Callaway M, Williams AJ, Sund Z, Powell T, Wong FS. The size of the spleen by magnetic resonance imaging in patients with cystic fibrosis; with and without diabetes--a novel observational study. QJM 2010; 103:237-42. [PMID: 20139101 DOI: 10.1093/qjmed/hcp193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Magnetic resonance imaging (MRI) has been shown to be a useful tool to evaluate the volume of the pancreas. There is currently no information about the size of the spleen in cystic fibrosis (CF) patients. PATIENTS AND METHODS We investigated 51 adult volunteers: 28 pancreatic insufficient CF patients [13 with CF-related diabetes (CFRD) and 15 non-diabetic] and 23 male non-CF patients [12 with type 1 diabetes mellitus (T1DM) and 11 healthy control subjects]. Patients with known liver cirrhosis or portal hypertension were excluded. The size of the spleen was measured in all subjects by an investigator unaware of patients' clinical status. For comparison of spleen size in the four study groups only male CF patients were included. For CF patients, spleen size was compared with forced expiratory volume in 1 s (FEV(1)), body mass index (BMI), total number of days of intravenous (IV) antibiotic treatment for pulmonary exacerbations in year previous to study, levels of circulating white blood cells, glycosylated haemoglobin A1c (HbA1c), and exocrine function of the pancreas, as assessed by daily requirement of oral lipase. RESULTS Amongst the four study groups, spleen size was greatest in the male non-diabetic CF patients (P = 0.01). For CF patients, spleen size was greater in male compared to female patients (P = 0.012). For patients with CFRD, there was an inverse correlation between the spleen size and HbA1c (r = -0.59, P = 0.04) and the daily intake of supplementary lipase (r = -0.63, P = 0.02). The size of the spleen in patients with CFRD, but not in CF patients without CFRD, inversely correlated with the days of IV antibiotic treatment received in the year previous to the study (r = -0.67, P = 0.012). There was no correlation between spleen size and BMI, FEV1 and white blood cell counts in any group. CONCLUSION On MRI, the spleen size was greatest in male non-diabetic CF patients in comparison with other groups. The size of the spleen in CFRD patients was smaller when diabetes was poorly controlled, when exocrine pancreatic function was greatly impaired and in those with greater need for IV antibiotics in the year prior to the study.
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Schmeisser ET, Vann RR, Williams AJ. Nonlinear dynamical characterization of magnocellular neural population response variability. J Vis 2010. [DOI: 10.1167/5.8.433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Hor YS, Williams AJ, Checkelsky JG, Roushan P, Seo J, Xu Q, Zandbergen HW, Yazdani A, Ong NP, Cava RJ. Superconductivity in CuxBi2Se3 and its implications for pairing in the undoped topological insulator. PHYSICAL REVIEW LETTERS 2010; 104:057001. [PMID: 20366785 DOI: 10.1103/physrevlett.104.057001] [Citation(s) in RCA: 242] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Indexed: 05/25/2023]
Abstract
Bi2Se3 is one of a handful of known topological insulators. Here we show that copper intercalation in the van der Waals gaps between the Bi2Se3 layers, yielding an electron concentration of approximately 2x10{20} cm{-3}, results in superconductivity at 3.8 K in CuxBi2Se3 for 0.12<or=x<or=0.15. This demonstrates that Cooper pairing is possible in Bi2Se3 at accessible temperatures, with implications for studying the physics of topological insulators and potential devices.
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Williams AJ, Davies CR, Mapstone BD, Currey LM, Welch DJ, Begg GA, Ballagh AC, Choat JH, Murchie CD, Simpfendorfer CA. Age-based demography of humpback grouper Cromileptes altivelis: implications for fisheries management and conservation. ENDANGER SPECIES RES 2009. [DOI: 10.3354/esr00237] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Carter AB, Williams AJ, Russ GR. Increased accuracy of batch fecundity estimates using oocyte stage ratios in Plectropomus leopardus. JOURNAL OF FISH BIOLOGY 2009; 75:716-722. [PMID: 20738569 DOI: 10.1111/j.1095-8649.2009.02313.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Using the ratio of the number of migratory nuclei to hydrated oocytes to estimate batch fecundity of common coral trout Plectropomus leopardus increases the time over which samples can be collected and, therefore, increases the sample size available and reduces biases in batch fecundity estimates.
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McQueen TM, Williams AJ, Stephens PW, Tao J, Zhu Y, Ksenofontov V, Casper F, Felser C, Cava RJ. Tetragonal-to-orthorhombic structural phase transition at 90 K in the superconductor Fe(1.01)Se. PHYSICAL REVIEW LETTERS 2009; 103:057002. [PMID: 19792526 DOI: 10.1103/physrevlett.103.057002] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Indexed: 05/25/2023]
Abstract
In this Letter we show that superconducting Fe(1.01)Se undergoes a structural transition at 90 K from a tetragonal to an orthorhombic phase but that nonsuperconducting Fe(1.03)Se does not. High resolution electron microscopy at low temperatures further reveals an unexpected additional modulation of the crystal structure of the superconducting phase that involves displacements of the Fe atoms, and that the nonsuperconducting composition shows a different, complex nanometer-scale structural modulation. Finally, we show that magnetism is not the driving force for the phase transition in the superconducting phase.
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Williams AJ, McQueen TM, Ksenofontov V, Felser C, Cava RJ. The metal-insulator transition in Fe(1.01-x)Cu(x)Se. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:305701. [PMID: 21828556 DOI: 10.1088/0953-8984/21/30/305701] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Iron selenide, Fe(1.01)Se, the layered parent compound of the recently discovered superconducting arsenide family, has previously been shown to be non-magnetic and superconducting with a critical temperature of 8 K. Here we show that copper can be substituted at the iron site in Fe(1.01)Se up to a solubility limit of 20-30%, after which a first-order transition to the three-dimensional CuFeSe(2) structure type is observed. As little as 1.5% copper is sufficient to suppress the superconductivity, and 4% drives the system through a metal-insulator transition. A local magnetic moment is introduced, which maximizes near 12% doping, where a spin-glass transition near 15 K is observed.
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Goddard CA, Ghais NS, Zhang Y, Williams AJ, Colledge WH, Grace AA, Huang CLH. Physiological consequences of the P2328S mutation in the ryanodine receptor (RyR2) gene in genetically modified murine hearts. Acta Physiol (Oxf) 2008; 194:123-40. [PMID: 18419777 PMCID: PMC2628439 DOI: 10.1111/j.1748-1716.2008.01865.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aim To explore the physiological consequences of the ryanodine receptor (RyR2)-P2328S mutation associated with catecholaminergic polymorphic ventricular tachycardia (CPVT). Methods We generated heterozygotic (RyR2p/s) and homozygotic (RyR2s/s) transgenic mice and studied Ca2+ signals from regularly stimulated, Fluo-3-loaded, cardiac myocytes. Results were compared with monophasic action potentials (MAPs) in Langendorff-perfused hearts under both regular and programmed electrical stimulation (PES). Results Evoked Ca2+ transients from wild-type (WT), heterozygote (RyR2p/s) and homozygote (RyR2s/s) myocytes had indistinguishable peak amplitudes with RyR2s/s showing subsidiary events. Adding 100 nm isoproterenol produced both ectopic peaks and subsidiary events in WT but not RyR2p/s and ectopic peaks and reduced amplitudes of evoked peaks in RyR2s/s. Regularly stimulated WT, RyR2p/s and RyR2s/s hearts showed indistinguishable MAP durations and refractory periods. RyR2p/s hearts showed non-sustained ventricular tachycardias (nsVTs) only with PES. Both nsVTs and sustained VTs (sVTs) occurred with regular stimuli and PES with isoproterenol treatment. RyR2s/s hearts showed higher incidences of nsVTs before but mainly sVTs after introduction of isoproterenol with both regular stimuli and PES, particularly at higher pacing frequencies. Additionally, intrinsically beating RyR2s/s showed extrasystolic events often followed by spontaneous sVT. Conclusion The RyR2-P2328S mutation results in marked alterations in cellular Ca2+ homeostasis and arrhythmogenic properties resembling CPVT with greater effects in the homozygote than the heterozygote demonstrating an important gene dosage effect.
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Williams AJ, Elyashberg ME, Blinov KA, Lankin DC, Martin GE, Reynolds WF, Porco JA, Singleton CA, Su S. Applying computer-assisted structure elucidation algorithms for the purpose of structure validation: revisiting the NMR assignments of hexacyclinol. JOURNAL OF NATURAL PRODUCTS 2008; 71:581-588. [PMID: 18257535 DOI: 10.1021/np070557t] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Computer-assisted structure elucidation (CASE) using a combination of 1D and 2D NMR data has been available for a number of years. These algorithms can be considered as "logic machines" capable of deriving all plausible structures from a set of structural constraints or "axioms", defined by the spectroscopic data and associated chemical information or prior knowledge. CASE programs allow the spectroscopist not only to determine structures from spectroscopic data but also to study the dependence of the proposed structure on changes to the set of axioms. In this article, we describe the application of the ACD/Structure Elucidator expert system to help resolve the conflict between two different hypothetical hexacyclinol structures derived by different researchers from the NMR spectra of this complex natural product. It has been shown that the combination of algorithms for both structure elucidation and structure validation delivered by the expert system enables the identification of the most probable structure as well as the associated chemical shift assignments.
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Blinov KA, Smurnyy YD, Elyashberg ME, Churanova TS, Kvasha M, Steinbeck C, Lefebvre BA, Williams AJ. Performance validation of neural network based (13)c NMR prediction using a publicly available data source. J Chem Inf Model 2008; 48:550-5. [PMID: 18293952 DOI: 10.1021/ci700363r] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The validation of the performance of a neural network based 13C NMR prediction algorithm using a test set available from an open source publicly available database, NMRShiftDB, is described. The validation was performed using a version of the database containing ca. 214,000 chemical shifts as well as for two subsets of the database to compare performance when overlap with the training set is taken into account. The first subset contained ca. 93,000 chemical shifts that were absent from the ACD\CNMR DB, the "excluded shift set" used for training of the neural network and the ACD\CNMR prediction algorithm, while the second contained ca. 121,000 shifts that were present in the ACD\CNMR DB training set, the "included shift set". This work has shown that the mean error between experimental and predicted shifts for the entire database is 1.59 ppm, while the mean deviation for the subset with included shifts is 1.47 and 1.74 ppm for excluded shifts. Since similar work has been reported online for another algorithm we compared the results with the errors determined using Robien's CNMR Neural Network Predictor using the entire NMRShiftDB for program validation.
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Murray RD, Williams AJ, Sheldon IM. Field investigation of perinatal mortality in friesian cattle associated with myocardial degeneration and necrosis. Reprod Domest Anim 2007; 43:339-345. [PMID: 18086254 DOI: 10.1111/j.1439-0531.2007.00911.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Perinatal mortality and stillbirths were investigated in an extensively managed herd of Friesian cows and heifers calving over a 2-year period: 504 cows were calved and 215 heifers. Cows were bred to Friesian and Jersey bulls using natural service. The perinatal fetal mortality rate was 7.5% for cows and 30% for heifers. An experienced stockman managed these calvings and veterinary assistance was required only on nine occasions. All stillborn fetuses were examined post-mortem by the Veterinary Laboratories Agency, Carmarthen and no infectious agent was identified on any occasion. Thyroid hyperplasia was found in two fetuses. In blood samples taken from 10 late pregnant heifers, mean glutathione peroxidase values were 7.9 +/- 1.7 IU/ml Packed Cell Volume (PCV). Tissues from eight fetuses were submitted to the University of Liverpool for histopathological examination; all presented lesions consistent with myocardial degeneration and necrosis of the left ventricle. Following treatment of 205 late pregnant heifers with sodium selenite and vitamin E, the overall perinatal mortality rate in these cattle fell to below 11%.
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Lett WR, Williams AJ. Extending human relations work with teachers. AUSTRALIAN PSYCHOLOGIST 2007. [DOI: 10.1080/00050067608255676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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