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Lewis S, Arnott D, Godfrey C, Britton J. Public health measures to reduce smoking prevalence in the UK: how many lives could be saved? Tob Control 2005; 14:251-4. [PMID: 16046688 PMCID: PMC1748066 DOI: 10.1136/tc.2005.011064] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To estimate the number of deaths that could be prevented in the UK by implementing population strategies to reduce smoking prevalence. DESIGN A prospective analysis of future mortality using recent national smoking prevalence data and relative risks of mortality in current smokers, ex-smokers, and never-smokers. POPULATION Smokers in the UK. INTERVENTIONS Population measures of proven effectiveness assumed to reduce smoking prevalence by 1 percentage point per year for 10 years, or alternatively by 13% over 19 years (1 percentage point per annum for seven years, 0.5 percentage point per annum for 12 years) as considered to be achievable in a recent report to the UK Chancellor of the Exchequer. MAIN OUTCOME MEASURE Estimated deaths from smoking prevented in the 35-75 year age group. RESULTS Reducing the prevalence of smoking by 1 percentage point each year for 10 years would prevent 69 049 deaths at ages between 35 and 74 years during that period. The model of reduction by 13% over 19 years would prevent 54 308 and 194 493 deaths in 10 and 19 years, respectively. Continued prevalence reductions at the current rate of 0.4 percentage points each year will prevent 23 192 deaths over 10 years. CONCLUSIONS Full implementation of simple population measures to encourage smoking cessation could prevent substantial numbers of deaths in the UK.
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Davey G, Venn A, Belete H, Berhane Y, Britton J. Wheeze, allergic sensitization and geohelminth infection in Butajira, Ethiopia. Clin Exp Allergy 2005; 35:301-7. [PMID: 15784107 DOI: 10.1111/j.1365-2222.2005.02181.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND The effect of geohelminth infection on wheeze and allergen sensitization is inconsistent across different epidemiological studies. OBJECTIVE To investigate the association between self-reported wheeze, self-reported asthma, allergic sensitization and geohelminth infection in urban and rural areas of Butajira, southern Ethiopia. METHODS Questionnaire data on wheeze, asthma and a range of confounding variables was gathered in a cross-sectional study of 7649 people aged 5 years or more from the Butajira Rural Health Project database. Allergic skin sensitization to Dermatophagoides pteronyssinus and cockroach was measured, and a stool sample collected for qualitative and quantitative geohelminth analysis. RESULTS Wheeze was weakly associated with allergic sensitization to D. pteronyssinus and cockroach (odds ratios (OR) 1.21, 95% confidence interval (CI) 0.98-1.51, and 1.27, 95% CI 1.00-1.62, respectively). Self-reported asthma was related to sensitization to D. pteronyssinus only (OR 4.09, 95% CI 2.86-5.84). Geohelminths were present in 33.8% of participants, and the median egg load in infested individuals was 6 eggs/g. Overall, presence of any geohelminths was associated with a diminished risk of cockroach sensitization (adjusted OR 0.82, 95% CI 0.68-0.99) but there were no significant protective effects of any geohelminth infection against wheeze or asthma. CONCLUSION In a developing country community with relatively low geohelminth prevalence and intensity, we found weak association between allergic sensitization and wheeze, but no evidence of a protective effect of geohelminths against wheeze or asthma.
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Langer C, Ozeri R, Jost JD, Chiaverini J, Demarco B, Ben-Kish A, Blakestad RB, Britton J, Hume DB, Itano WM, Leibfried D, Reichle R, Rosenband T, Schaetz T, Schmidt PO, Wineland DJ. Long-lived qubit memory using atomic ions. PHYSICAL REVIEW LETTERS 2005; 95:060502. [PMID: 16090932 DOI: 10.1103/physrevlett.95.060502] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2005] [Indexed: 05/03/2023]
Abstract
We demonstrate experimentally a robust quantum memory using a magnetic-field-independent hyperfine transition in 9Be+ atomic ion qubits at a magnetic field B approximately = 0.01194 T. We observe that the single physical qubit memory coherence time is greater than 10 s, an improvement of approximately 5 orders of magnitude from previous experiments with 9Be+. We also observe long coherence times of decoherence-free subspace logical qubits comprising two entangled physical qubits and discuss the merits of each type of qubit.
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Hubbard R, Lewis S, West J, Smith C, Godfrey C, Smeeth L, Farrington P, Britton J. Bupropion and the risk of sudden death: a self-controlled case-series analysis using The Health Improvement Network. Thorax 2005; 60:848-50. [PMID: 16055620 PMCID: PMC1747199 DOI: 10.1136/thx.2005.041798] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Bupropion is an effective smoking cessation therapy but its use in the UK has been limited by concerns that it may increase the risk of sudden death. METHODS Data for all patients prescribed bupropion within The Health Improvement Network (a computerised general practice database) were extracted and the self-controlled case-series method was used to estimate the relative incidence of death during the first 28 days of treatment. The incidence of seizures, a recognised adverse effect of bupropion, was also investigated during this period. RESULTS A total of 9329 individuals had been prescribed bupropion (mean age 44 years, 48% male). The total person-time after the first prescription for bupropion was 17,586 years, and during this time 121 people died. Two people died within the first 28 days of treatment, which was less than expected in comparison with the remaining observation period by an incidence ratio of 0.50 (95% confidence interval (CI) 0.12 to 2.05). Twenty eight people were recorded as having a total of 45 seizures (23 before starting bupropion, two in the first 28 days of treatment, and 20 at a later point). The relative incidence of seizures during the first 28 days of treatment was 3.62 (95% CI 0.87 to 15.09), equivalent to one additional seizure per 6219 first time bupropion users. CONCLUSIONS Bupropion use is probably associated with an increased risk of seizures, but no evidence was found to suggest that the drug is associated with an increased risk of sudden death.
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Ozeri R, Langer C, Jost JD, DeMarco B, Ben-Kish A, Blakestad BR, Britton J, Chiaverini J, Itano WM, Hume DB, Leibfried D, Rosenband T, Schmidt PO, Wineland DJ. Hyperfine coherence in the presence of spontaneous photon scattering. PHYSICAL REVIEW LETTERS 2005; 95:030403. [PMID: 16090723 DOI: 10.1103/physrevlett.95.030403] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2005] [Indexed: 05/03/2023]
Abstract
The coherence of a hyperfine-state superposition of a trapped 9Be+ ion in the presence of off-resonant light is studied experimentally. It is shown that Rayleigh elastic scattering of photons that does not change state populations also does not affect coherence. We observe coherence times that exceed the average scattering time of 19 photons which is determined from measured Stark shifts. This result implies that, with sufficient control over its parameters, laser light can be used to manipulate hyperfine-state superpositions with very little decoherence.
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Haileamlak A, Lewis SA, Britton J, Venn AJ, Woldemariam D, Hubbard R, Williams HC. Validation of the International Study of Asthma and Allergies in Children (ISAAC) and U.K. criteria for atopic eczema in Ethiopian children. Br J Dermatol 2005; 152:735-41. [PMID: 15840106 DOI: 10.1111/j.1365-2133.2005.06511.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Reliable diagnostic criteria for atopic eczema (AE) are essential in order to make international comparisons and to identify possible disease risk factors. Little is known about the prevalence of atopic eczema and validity of diagnostic criteria for AE in developing countries where English is not the first language. OBJECTIVES We sought to determine the prevalence of AE in an area of urban and rural Ethiopia, and to compare the predictive values of different questionnaire and examination methods for diagnosing AE in this population. METHODS We conducted a cross-sectional survey of 7915 children aged 1-5 years living in and around the town of Jimma in southwest Ethiopia. AE prevalence was assessed in two ways: (i) by using the International Study for Asthma and Allergies in Childhood (ISAAC) questionnaire, and (ii) using the U.K. refinement of Hanifin and Rajka's diagnostic criteria. All possible cases identified by screening questions and random samples of controls were then examined by an experienced local paediatrician, who acted as a reference standard to determine the predictive value of the criteria used to diagnose AE. RESULTS The overall 1-year period prevalence of AE according to ISAAC and U.K. criteria was 4.4%[95% confidence interval (CI) 3.95-4.85] and 1.8% (95% CI 1.5-2.1), respectively. Corresponding point prevalence estimates (symptoms in the last week) were 1.8% for ISAAC and 1.3% for the U.K. criteria. The positive predictive values of the ISAAC and U.K. criteria questions for AE symptoms still reported to be present (in the last week) at the doctor's examination were 48.8% and 55.5%, respectively. Corresponding negative predictive values were 90.5% and 90.1%, respectively. The sign of visible flexural dermatitis (a component of the U.K. criteria) when used alone had positive and negative predictive values of 57% and 91%, respectively. CONCLUSIONS Neither the ISAAC nor U.K. criteria performed especially well in predicting cases of AE in this survey. Possible reasons include problems with questionnaire translation, cultural conceptions of terminology, asking parents rather than the child about symptoms, the transient nature of AE signs, and differences in what a doctor perceives to constitute a typical case of AE. The results do not preclude the use of standardized diagnostic criteria alongside a doctor's examination in future surveys of Ethiopian children, and knowledge of the criteria's limited predictive value should help to interpret study findings that have employed such criteria. Consideration should be given to adopting the sign of visible flexural dermatitis as a standard for estimating the point prevalence of AE throughout the world because it is less susceptible to problems with translation and interpretation.
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Venn A, Yemaneberhan H, Lewis S, Parry E, Britton J. Proximity of the home to roads and the risk of wheeze in an Ethiopian population. Occup Environ Med 2005; 62:376-80. [PMID: 15901884 PMCID: PMC1741025 DOI: 10.1136/oem.2004.017228] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND There is widespread public concern that exposure to road vehicle traffic pollution causes asthma, but epidemiological studies in developed countries have not generally confirmed a strong effect and may have underestimated the risk as a result of relatively high and widespread exposure to traffic in everyday life. AIMS To investigate the effect of living close to a traffic bearing road on the risk of wheezing in Jimma, Ethiopia where road traffic is generally low and restricted to a limited network of roads. METHODS Data have been previously collected on respiratory symptoms, allergic sensitisation, and numerous demographic and lifestyle factors in a systematic sample of inhabitants of Jimma town. In 2003 the homes of these people were retraced; the shortest distance to the nearest surfaced road, and traffic flows on these roads were measured. RESULTS Distance measurements were collected for 7609 (80%) individuals. The overall prevalence of wheeze was similar in those living within 150 m of a road compared to those living further away (3.9% v 3.7%), but among the 3592 individuals living within 150 m, the risk of wheeze increased significantly in linear relation to proximity to the road (adjusted odds ratio = 1.17 per 30 m proximity, 95% CI 1.01 to 1.36). This relation was stronger, though not significantly so, for roads with above median traffic flows. CONCLUSION These findings indicate that living in close proximity to road vehicle traffic is associated with an increased risk of wheeze, but that other environmental factors are also likely to be important.
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Chiaverini J, Britton J, Leibfried D, Knill E, Barrett MD, Blakestad RB, Itano WM, Jost JD, Langer C, Ozeri R, Schaetz T, Wineland DJ. Implementation of the Semiclassical Quantum Fourier Transform in a Scalable System. Science 2005; 308:997-1000. [PMID: 15890877 DOI: 10.1126/science.1110335] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We report the implementation of the semiclassical quantum Fourier transform in a system of three beryllium ion qubits (two-level quantum systems) confined in a segmented multizone trap. The quantum Fourier transform is the crucial final step in Shor's algorithm, and it acts on a register of qubits to determine the periodicity of the quantum state's amplitudes. Because only probability amplitudes are required for this task, a more efficient semiclassical version can be used, for which only single-qubit operations conditioned on measurement outcomes are required. We apply the transform to several input states of different periodicities; the results enable the location of peaks corresponding to the original periods. This demonstration incorporates the key elements of a scalable ion-trap architecture, suggesting the future capability of applying the quantum Fourier transform to a large number of qubits as required for a useful quantum factoring algorithm.
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Lewis SA, Antoniak M, Venn AJ, Davies L, Goodwin A, Salfield N, Britton J, Fogarty AW. Secondhand smoke, dietary fruit intake, road traffic exposures, and the prevalence of asthma: a cross-sectional study in young children. Am J Epidemiol 2005; 161:406-11. [PMID: 15718476 DOI: 10.1093/aje/kwi059] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The authors have investigated the independent effects of exposure to secondhand smoke, road vehicle traffic, and dietary fruit intake in a cross-sectional study of asthma in young children. They surveyed all children aged 4-6 years in 235 schools in the East Midlands and East of England regions of the United Kingdom in 2003. Data on respiratory symptoms, diagnoses and treatment, smoking in the home, and dietary fruit intake were collected by parental questionnaire. A geographic information system was used to map postcodes and determine the distance of the home from the nearest main road. Responses were obtained from 11,562 children. Wheeze in the past year and physician-diagnosed asthma were reported by 14.1% and 18.2%, respectively. Both of these outcomes were more common in children who lived with a smoker, and the prevalence of asthma increased with the number of smokers in the home. Asthma prevalence was not associated with proximity of the home to a main road or with dietary fruit intake. The authors conclude that, of the potential risk factors considered in this study, preventing secondhand smoke exposure may be the most effective way of preventing asthma.
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Schaetz T, Barrett MD, Leibfried D, Britton J, Chiaverini J, Itano WM, Jost JD, Knill E, Langer C, Wineland DJ. Enhanced quantum state detection efficiency through quantum information processing. PHYSICAL REVIEW LETTERS 2005; 94:010501. [PMID: 15698054 DOI: 10.1103/physrevlett.94.010501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2004] [Indexed: 05/24/2023]
Abstract
We investigate theoretically and experimentally how quantum state-detection efficiency is improved by the use of quantum information processing (QIP). Experimentally, we encode the state of one 9Be(+) ion qubit with one additional ancilla qubit. By measuring both qubits, we reduce the state-detection error in the presence of noise. The deviation from the theoretically allowed reduction is due to infidelities of the QIP operations. Applying this general scheme to more ancilla qubits suggests that error in the individual qubit measurements need not be a limit to scalable quantum computation.
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Chiaverini J, Leibfried D, Schaetz T, Barrett MD, Blakestad RB, Britton J, Itano WM, Jost JD, Knill E, Langer C, Ozeri R, Wineland DJ. Realization of quantum error correction. Nature 2005; 432:602-5. [PMID: 15577904 DOI: 10.1038/nature03074] [Citation(s) in RCA: 321] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2004] [Accepted: 10/01/2004] [Indexed: 11/08/2022]
Abstract
Scalable quantum computation and communication require error control to protect quantum information against unavoidable noise. Quantum error correction protects information stored in two-level quantum systems (qubits) by rectifying errors with operations conditioned on the measurement outcomes. Error-correction protocols have been implemented in nuclear magnetic resonance experiments, but the inherent limitations of this technique prevent its application to quantum information processing. Here we experimentally demonstrate quantum error correction using three beryllium atomic-ion qubits confined to a linear, multi-zone trap. An encoded one-qubit state is protected against spin-flip errors by means of a three-qubit quantum error-correcting code. A primary ion qubit is prepared in an initial state, which is then encoded into an entangled state of three physical qubits (the primary and two ancilla qubits). Errors are induced simultaneously in all qubits at various rates. The encoded state is decoded back to the primary ion one-qubit state, making error information available on the ancilla ions, which are separated from the primary ion and measured. Finally, the primary qubit state is corrected on the basis of the ancillae measurement outcome. We verify error correction by comparing the corrected final state to the uncorrected state and to the initial state. In principle, the approach enables a quantum state to be maintained by means of repeated error correction, an important step towards scalable fault-tolerant quantum computation using trapped ions.
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Broadfield EC, McKeever TM, Whitehurst A, Lewis SA, Lawson N, Britton J, Fogarty A. A case-control study of dietary and erythrocyte membrane fatty acids in asthma. Clin Exp Allergy 2004; 34:1232-6. [PMID: 15298563 DOI: 10.1111/j.1365-2222.2004.02032.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Epidemiological evidence suggests that increased dietary omega-6 and reduced omega-3 fatty acid intake, may have contributed to the rising prevalence of asthma, but these hypotheses have not been tested in studies comparing both dietary intake and objective measures of polyunsaturated fatty acids. OBJECTIVE To assess whether a higher intake of omega-6 or a lower intake of omega-3 fatty acids increases the risk of asthma, by measuring dietary fatty acid intake by a food frequency questionnaire (FFQ) and erythrocyte membrane fatty acids, as an objective biomarker of intake. METHODS We have compared individual fatty acid intake estimated by FFQ and by mass spectrometry of fasting erythrocyte cell membranes in 89 cases of asthma and 89 community-matched controls. RESULTS The odds of asthma were increased in relation to intake of the omega-3 fatty acids eicosapentaenoic acid (odds ratio (OR) for difference between the 25th and 75th centiles of intake= 1.89, 95% CI 1.15-3.11) and docosahexaenoic acid (OR = 2.11, 95% CI 1.19-3.74). There was no evidence of any difference in erythrocyte membrane levels of omega-3 fatty acids, while the odds of asthma were reduced in relation to linoleic acid (omega-6) membrane levels (OR = 0.45, 95% CI 0.21-0.95). CONCLUSION These findings suggest that dietary omega-3 fatty acids do not play a major role in protecting against asthma, and that higher levels of erythrocyte membrane linoleic acid are associated with a lower risk of asthma.
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Roddy E, Rubin P, Britton J. A study of smoking and smoking cessation on the curricula of UK medical schools. Tob Control 2004; 13:74-7. [PMID: 14985601 PMCID: PMC1747835 DOI: 10.1136/tc.2003.004572] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES To identify current practice in teaching on smoking and smoking cessation in UK medical schools, and establish whether newly qualified UK doctors feel prepared to deliver smoking cessation interventions. DESIGN Search of published curricula from all UK medical schools; questionnaire surveys of all UK medical school deans and UK qualified pre-registration house officers (PRHOs). PARTICIPANTS Deans or nominated representatives from all 24 UK medical schools with current undergraduates, and all UK qualified PRHOs. MAIN OUTCOME MEASURES Inclusion and organisation in curriculum of 15 predefined core topics related to smoking (deans); perceived readiness to deliver smoking cessation interventions (PRHOs). RESULTS There was no mention of smoking or smoking cessation in the published curriculum material of 10 (42%) medical schools. Deans reported compulsory teaching on a mean (SD) of 9.5 (2.8) core topics, while PRHOs recalled compulsory teaching in only 6.6 (3.2). Training in clinical aspects of smoking cessation was particularly neglected, with 60% of PRHOs reporting that they graduated unable to deliver smoking cessation interventions in accordance with national guidelines. Only 17% of PRHOs felt well prepared to deliver advice on using nicotine replacement therapy, and 5% on bupropion. CONCLUSIONS Teaching on smoking cessation in UK medical schools is inadequate.
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Pearson PJK, Lewis SA, Britton J, Fogarty A. Vitamin E supplements in asthma: a parallel group randomised placebo controlled trial. Thorax 2004; 59:652-6. [PMID: 15282383 PMCID: PMC1747112 DOI: 10.1136/thx.2004.022616] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND Increased dietary vitamin E intake is associated with a reduced incidence of asthma, and combinations of antioxidant supplements including vitamin E are effective in reducing ozone induced bronchoconstriction. A study was undertaken to investigate the effect of supplementation with vitamin E for 6 weeks on bronchial hyperresponsiveness in atopic adults with asthma. METHODS 72 participants from a clinical trial register of adults with asthma were randomised to receive 500 mg natural vitamin E or matched placebo for 6 weeks in a placebo controlled, double blind parallel group clinical trial. Inclusion criteria included age 18-60 years, maintenance treatment of at least one dose of inhaled corticosteroid per day, a positive skin prick test to one of three common allergens, and bronchial hyperresponsiveness to methacholine (defined as a dose provoking a 20% fall in forced expiratory volume in 1 second (FEV(1)) (PD(20)) of 12.25 micromol). Secondary outcomes were FEV(1), forced vital capacity, mean morning and evening peak flow, symptom scores, bronchodilator use, and serum immunoglobulin E levels. RESULTS In the primary intention to treat analysis the change in PD(20) was similar in the vitamin E and placebo groups with a mean difference of +0.25 doubling doses of methacholine (95% confidence interval -0.67 to +1.16 greater with vitamin E). There was no effect of vitamin E supplementation on any other measure of asthma control, either in the intention to treat or per protocol analysis. There was also no effect of vitamin E supplementation on serum immunoglobulin levels. CONCLUSION Dietary supplementation with vitamin E adds no benefit to current standard treatment in adults with mild to moderate asthma.
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Yemaneberhan H, Flohr C, Lewis SA, Bekele Z, Parry E, Williams HC, Britton J, Venn A. Prevalence and associated factors of atopic dermatitis symptoms in rural and urban Ethiopia. Clin Exp Allergy 2004; 34:779-85. [PMID: 15144471 DOI: 10.1111/j.1365-2222.2004.1946.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Allergic diseases, including atopic dermatitis (AD), are increasingly becoming a clinical problem in developing countries. OBJECTIVE We investigated the prevalence of AD symptoms and the effects of potential environmental aetiologies in rural and urban areas of Jimma in southwestern Ethiopia. METHODS Information on allergic disease symptoms and lifestyle factors was gathered in an interviewer-led cross-sectional questionnaire-based population survey of 9844 urban and 3032 rural participants of all ages. A one-in-four subsample underwent skin prick testing for hypersensitivity to Dermatophagoides pteronyssinus, mixed threshings, and aspergillus. RESULTS Around 95% of those eligible took part in the survey. Lifetime cumulative prevalence of AD symptoms was generally low with an overall prevalence of 1.2%, but was higher in the urban (1.5%) than in the rural area (0.3%; odds ratio (OR)=4.45 [95% CI 2.34-8.47]). AD symptoms were strongly associated with wheeze (adjusted OR=22.03 [15.45-31.42]) and rhinitis symptoms (61.94 [42.66-89.95]). Of several environmental exposures assessed, residence in a house made of brick (rather than mud) walls with wooden (rather than clay) floor, exposure to cigarette smoke as a child, having lived outside of Jimma in the past, and being of the Tigrean ethnic group were associated with an increased risk of AD symptoms. CONCLUSION Although the overall prevalence of AD symptoms was low in this Ethiopian population, a marked urban-rural gradient was evident. Lifestyle factors linked to urbanization were associated with an increased risk of AD symptoms.
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Schaetz T, Barrett MD, Leibfried D, Chiaverini J, Britton J, Itano WM, Jost JD, Langer C, Wineland DJ. Quantum dense coding with atomic qubits. PHYSICAL REVIEW LETTERS 2004; 93:040505. [PMID: 15323743 DOI: 10.1103/physrevlett.93.040505] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2004] [Indexed: 05/24/2023]
Abstract
We report the implementation of quantum dense coding on individual atomic qubits with the use of two trapped 9Be+ ions. The protocol is implemented with a complete Bell measurement that distinguishes the four operations used to encode two bits of classical information. We measure an average transmission fidelity of 0.85(1) and determine a channel capacity of 1.16(1).
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Barrett MD, Chiaverini J, Schaetz T, Britton J, Itano WM, Jost JD, Knill E, Langer C, Leibfried D, Ozeri R, Wineland DJ. Deterministic quantum teleportation of atomic qubits. Nature 2004; 429:737-9. [PMID: 15201904 DOI: 10.1038/nature02608] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2004] [Accepted: 05/04/2004] [Indexed: 11/08/2022]
Abstract
Quantum teleportation provides a means to transport quantum information efficiently from one location to another, without the physical transfer of the associated quantum-information carrier. This is achieved by using the non-local correlations of previously distributed, entangled quantum bits (qubits). Teleportation is expected to play an integral role in quantum communication and quantum computation. Previous experimental demonstrations have been implemented with optical systems that used both discrete and continuous variables, and with liquid-state nuclear magnetic resonance. Here we report unconditional teleportation of massive particle qubits using atomic (9Be+) ions confined in a segmented ion trap, which aids individual qubit addressing. We achieve an average fidelity of 78 per cent, which exceeds the fidelity of any protocol that does not use entanglement. This demonstration is also important because it incorporates most of the techniques necessary for scalable quantum information processing in an ion-trap system.
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Fogarty A, Broadfield E, Lewis S, Lawson N, Britton J. Amino acids and asthma: a case-control study. Eur Respir J 2004; 23:565-8. [PMID: 15083755 DOI: 10.1183/09031936.04.00090404] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Amino acids contribute to various anti-oxidant and immunological activities relevant to asthma pathogenesis, raising the possibility that differences in amino acids may be involved in asthma aetiology. The authors hypothesised that cystine reduces the risk of asthma via glutathione metabolism. Methionine, glutamine, glutamic acid and glycine may have potential protective effects, whilst arginine, phenylalanine and tryptophan may have adverse effects in asthma. Fasting plasma levels of amino acids were compared in a case-control study. A total of 89 adults, aged 18-65 yrs, with asthma controlled by inhaled corticosteroids, were recruited from a volunteer database and local primary care registers, and compared with 89 controls individually matched for age, sex and primary care centre. Contrary to the primary hypothesis, cases had higher fasting plasma cystine levels than controls, and there was no difference between cases and controls in any of the other amino acids tested, with the exception of plasma glycine, which was associated with a strongly reduced risk of asthma (odds ratio for the highest tertile compared to lowest 0.30 (95% confidence interval (0.11-0.82)). This study negates the hypothesis that higher fasting plasma cystine levels have a protective effect on the risk of asthma, although the inverse correlation with plasma glycine deserves further investigation.
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Leibfried D, Barrett MD, Schaetz T, Britton J, Chiaverini J, Itano WM, Jost JD, Langer C, Wineland DJ. Toward Heisenberg-Limited Spectroscopy with Multiparticle Entangled States. Science 2004; 304:1476-8. [PMID: 15178794 DOI: 10.1126/science.1097576] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The precision in spectroscopy of any quantum system is fundamentally limited by the Heisenberg uncertainty relation for energy and time. For N systems, this limit requires that they be in a quantum-mechanically entangled state. We describe a scalable method of spectroscopy that can potentially take full advantage of entanglement to reach the Heisenberg limit and has the practical advantage that the spectroscopic information is transferred to states with optimal protection against readout noise. We demonstrate our method experimentally with three beryllium ions. The spectroscopic sensitivity attained is 1.45(2) times as high as that of a perfect experiment with three non-entangled particles.
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Cork MJ, Britton J, Butler L, Young S, Murphy R, Keohane SG. Comparison of parent knowledge, therapy utilization and severity of atopic eczema before and after explanation and demonstration of topical therapies by a specialist dermatology nurse. Br J Dermatol 2003; 149:582-9. [PMID: 14510993 DOI: 10.1046/j.1365-2133.2003.05595.x] [Citation(s) in RCA: 195] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The failure of patients to take medicines in a way that leads to clinical benefit is a major challenge. A consensus has emerged that, on average, compliance sufficient to obtain therapeutic objectives occurs about half the time, with noncompliance contributing to therapeutic failure in the other half. These figures refer to simple oral regimens. There has been little work assessing compliance/concordance with complex treatment regimens for atopic eczema. Asthma schools led by specialist nurses have been shown to improve knowledge, use of therapies and clinical outcome. OBJECTIVES To determine the effect of education and demonstration of topical therapies by specialist dermatology nurses on therapy utilization and severity of atopic eczema. METHODS Fifty-one children with atopic eczema attending a paediatric dermatology clinic were followed for up to 1 year. At each visit the parent's knowledge about atopic eczema and its treatment and therapy utilization was recorded. The severity of the eczema was recorded using the six area, six sign atopic dermatitis severity score (SASSAD) and parental assessment of itch, sleep disturbance and irritability. At the first visit a specialist dermatology nurse explained and demonstrated how to use all of the topical treatments. This education was repeated at subsequent visits depending on the knowledge of the parent. RESULTS At baseline less than 5% of parents had received/recalled receiving any explanation of the causes of eczema or demonstration of how to apply topical treatments. The eczema was poorly controlled in all children (mean SASSAD 42.9). Of the children, 24% were not being treated with any emollient cream/ointment; the mean use was 54 g weekly. Of the children, 25% were being inappropriately treated with potent or very potent topical steroids. Following repeated education and demonstration of topical therapies by a specialist dermatology nurse, there was an 89% reduction in the severity of the eczema. The main change in therapy utilization was an 800% increase in the use of emollients (to 426 g weekly of emollient cream/ointment) and no overall increase in the use of topical steroids, accounting for potency and quantity used. CONCLUSIONS This study reinforces the importance of specialist dermatology nurses in the management of atopic eczema. It also confirms the opinion of patients, patient support groups, dermatologists and best practice guidelines that the most important intervention in the management of atopic eczema is to spend time to listen and explain its causes and demonstrate how to apply topical therapies.
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Fogarty A, Lewis SA, Scrivener SL, Antoniak M, Pacey S, Pringle M, Britton J. Oral magnesium and vitamin C supplements in asthma: a parallel group randomized placebo-controlled trial. Clin Exp Allergy 2003; 33:1355-9. [PMID: 14519140 DOI: 10.1046/j.1365-2222.2003.01777.x] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Epidemiological studies suggest that higher intakes of dietary vitamin C and magnesium may be associated with a reduced risk of asthma. OBJECTIVE To determine whether vitamin C or magnesium supplements improve the clinical control of asthma in primary care patients. METHODS A randomized, placebo-controlled, double-blind parallel group trial of 16 weeks supplementation with 1 g/day vitamin C, 450 mg/day magnesium chelate or matched placebo. Three hundred patients aged 18-60 years with physician-diagnosed asthma, controlled with at least one dose of an inhaled corticosteroid daily, were recruited from 24 primary care practices in Nottingham, UK. The main outcome measures were change in forced expiratory volume in 1 s, forced vital capacity, airway responsiveness to methacholine, mean morning and evening peak flow, symptom scores and bronchodilator use, both individually and as a combined summary statistic. RESULTS There was no evidence of any beneficial effect of either supplement on any outcome measure of asthma control in the primary intention-to-treat analysis, or in an analysis restricted to participants who completed the study. CONCLUSIONS Regular dietary supplementation with vitamin C or magnesium adds no clinical benefit to current standard therapy of asthma in primary care patients.
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Brada M, Viviers L, Abson C, Hines F, Britton J, Ashley S, Sardell S, Traish D, Gonsalves A, Wilkins P, Westbury C. Phase II study of primary temozolomide chemotherapy in patients with WHO grade II gliomas. Ann Oncol 2003; 14:1715-21. [PMID: 14630674 DOI: 10.1093/annonc/mdg371] [Citation(s) in RCA: 207] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The aim of this study was to assess the efficacy of temozolomide in patients with World Health Organisation (WHO) grade II gliomas treated with surgery alone using imaging and clinical criteria. PATIENTS AND METHODS Thirty patients with histologically verified WHO grade II gliomas (17 astrocytoma, 11 oligodendroglioma, two mixed oligoastrocytoma) following surgery 2-104 months (median 23 months) after initial diagnosis received temozolomide 200 mg/m(2)/day for 5 days, on a 28-day cycle, for a maximum of 12 cycles or until tumour progression. Median age was 40 years (range 25-68 years). Median follow-up from entry into the study was 3 years [range 23-47 months (for patients alive)]. Objective response was assessed by 3-monthly magnetic resonance imaging and monthly health-related quality of life (HQoL) and clinical assessment. Tumour size was measured as the high signal intensity area on fluid attenuated inversion recovery sequences. Responses were assessed using change in the product of two perpendicular diameters as complete response (CR), partial response (PR), minimal response (MR), stable disease (SD) and progressive disease (PD). RESULTS Twenty-nine of 30 patients entered into the study were evaluable for response. Three patients had a PR, 14 MR, 11 SD and one PD. Twenty-four patients received 12 cycles of chemotherapy. Of 29 evaluable patients, three discontinued after four, five and six cycles and two after 10 cycles. Nine patients progressed (three during chemotherapy-one PD and two initial SD-and six after completion of chemotherapy); five had evidence of transformation. The 3-year progression-free survival was 66%. Five patients died; the actuarial 3-year survival was 82%. Ninety-six per cent of patients with impaired HQoL had improvement in at least one HQoL domain. There was improvement in 115 of the 207 domains (56%). Fifteen of 28 patients (54%) with epilepsy had reduction in seizure frequency, of whom six became seizure free. Six patients had transient grade III/IV haematological toxicity (11 episodes; 3.5%). CONCLUSIONS Temozolomide has single-agent activity in patients with WHO grade II cerebral glioma, with modest improvement in quality of life and improvement in epilepsy control. On present evidence, temozolomide cannot be considered as primary therapy without formal comparison with other treatment modalities.
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Venn AJ, Cooper M, Antoniak M, Laughlin C, Britton J, Lewis SA. Effects of volatile organic compounds, damp, and other environmental exposures in the home on wheezing illness in children. Thorax 2003; 58:955-60. [PMID: 14586048 PMCID: PMC1746513 DOI: 10.1136/thorax.58.11.955] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND The effects of indoor exposure to volatile organic compounds (VOCs), including formaldehyde, on respiratory health are not clearly understood. The aim of this study was to determine the independent effects of VOCs and other common environmental exposures in the home on the risk and severity of persistent wheezing illness in children. METHODS Total volatile organic compounds, formaldehyde, nitrogen dioxide, damp (on a four category scale of % wood moisture equivalent), and environmental tobacco smoke (from salivary cotinine) were measured objectively in the homes of 193 children with persistent wheezing illness and 223 controls aged 9-11 years in Nottingham, UK. RESULTS The risk of wheezing illness was significantly increased only in relation to damp (odds ratio (OR) per increasing category=1.32 (95% confidence interval (CI), 1.00 to 1.75)), and was unrelated to the other exposures measured. Among cases, formaldehyde and damp were associated with more frequent nocturnal symptoms (OR per increasing quartile and category, respectively, 1.45 (1.06 to 1.98) and 1.97 (1.10 to 3.53)), significantly more so in atopic cases, but there was no effect of total volatile organic compounds, nitrogen dioxide, or cotinine. CONCLUSIONS Domestic volatile organic compounds are not a major determinant of risk or severity of childhood wheezing illness, though formaldehyde may increase symptom severity. Indoor damp increases both the risk and severity of childhood wheezing illness.
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McDonnell L, Maginnis C, Lewis S, Pickering N, Antoniak M, Hubbard R, Lawson I, Britton J. Occupational exposure to solvents and metals and Parkinson's disease. Neurology 2003; 61:716-7. [PMID: 12963777 DOI: 10.1212/wnl.61.5.716] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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