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1

Digitale Medien

Hexapole magnet system for thermal energy 3He atom manipulation (2001)

Jardine, A. P. ; Fouquet, P. ; Ellis, J. ; [weitere]

[S.l.] : American Institute of Physics (AIP)

Review of Scientific Instruments 72 (2001), S. 3834-3841

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ISSN: 1089-7623

Quelle: AIP Digital Archive

Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik

Notizen: We present design and construction details for a novel high field, small bore permanent hexapole magnet. The design is intended for focusing atomic beams of 3He at thermal energies. The magnet uses an optimized polepiece design which includes vacuum gaps to enable its use with high intensity atomic and molecular beams. The 0.3 m long, 1 mm internal radius magnet achieves a polepiece tip field of 1.1 T using NdFeB permanent magnets and Permendur 49 polepieces. The polepiece shanks are designed to saturate so that the hexapole properties are determined predominantly by the shape of the polepiece tip. The performance of the hexapole assembly is demonstrated with an 8 meV 3He beam in the beam source of the Cambridge spin echo spectrometer and the measured focused beam results show excellent agreement with theoretical predictions and negligible beam attenuation. © 2001 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.1405794

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2

Digitale Medien

Current–voltage characteristics of a GaAs Schottky diode accounting for leakage paths (2000)

Ellis, J. A. ; Barnes, P. A.

Woodbury, NY : American Institute of Physics (AIP)

Applied Physics Letters 76 (2000), S. 124-125

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ISSN: 1077-3118

Quelle: AIP Digital Archive

Thema: Physik

Notizen: Many fabricated Schottky diodes exhibit significant deviations from the theoretically calculated current–voltage (I–V) characteristics of ideal Schottky diodes. Attempts have been made to account for this deviation using interface states or surface state densities. Previous models have used the interfacial layer model to analyze the nonideal I–V characteristics of a GaAs Schottky barrier. We show here how nonideal behavior can be explained by considering surface leakage currents and material resistance. The standard figure of merit of Schottky diodes is the ideality factor, which can be obtained from measurements of δV/δ ln(I). By taking into account device resistance and shunt leakage paths with physically appropriate parameters, a relationship between δV/δ ln(I) and voltage can be established, which yields a better understanding of transport across the interface(s) of real Schottky diodes. © 2000 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.125677

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3

Digitale Medien

Helium atom scattering study of the frustrated translation mode of CO adsorbed on the Cu(001) surface (1995)

Ellis, J. ; Toennies, J. P. ; Witte, G.

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 102 (1995), S. 5059-5070

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ISSN: 1089-7690

Quelle: AIP Digital Archive

Thema: Physik , Chemie und Pharmazie

Notizen: The structure and vibrational modes of CO adsorbed on Cu(001) have been investigated by helium atom scattering (HAS). Below coverages of θ=0.13, CO adsorbs as isolated molecules, and the time of flight (TOF) spectra of helium atoms scattered from the surface are characterized by energy losses and gains of 3.94 ± 0.07 meV. With the aid of isotope shift measurements, this mode is unambiguously assigned to the frustrated translation mode of the adsorbed CO. In the c(2×2) structure (θ=0.5) this mode is found to show dispersion in both the 〈100〉 and 〈110〉 azimuths with frequencies ranging from 3.9 meV at the zone origin to 5.6 meV at the zone boundary. A simple force constant model with a single nearest neighbor force constant within the layer is found to be sufficient to describe the dispersion. For coverages slightly less than θ=0.5 the angular distributions of scattered helium atoms show features characteristic of vacancies in the overlayer. In the TOF spectra an additional nondispersive mode at about 4 meV is also seen and assigned to the frustrated translation of CO molecules adjacent to the vacancies in the c(2×2) overlayer. The Rayleigh mode is clearly observed in the c(2×2) structure but is found to decrease slightly in frequency while the longitudinal resonance, which is especially prominent on the clean surface, disappears completely. The results are interpreted with the aid of slab calculations. © 1995 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.469555

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4

Digitale Medien

Sustainable Urban-Drainage Systems and Catchment Planning (2002)

Ellis, J. B. ; D'Arcy, B. J. ; Chatfield, P. R.

Oxford, UK : Blackwell Publishing Ltd

Water and environment journal 16 (2002), S. 0

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ISSN: 1747-6593

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Energietechnik

Notizen: Partnership initiatives to address the problem of diffuse pollution from impermeable surface runoff within urban catchments are reviewed, with particular reference to mutual stakeholder duties and interests which are vested in the regulatory agencies, planning authorities, developers, water companies and highway agencies within the UK. The role of ‘sustainable urban-drainage systems’within integrated catchment-based approaches is considered in the context of the requirements of the EU Water Framework Directive and strategic river-basin management planning.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1111/j.1747-6593.2002.tb00418.x

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5

Digitale Medien

Infiltration Systems: A Sustainable Source-Control Option for Urban Stormwater Quality Management? (2000)

Ellis, J. B.

Oxford, UK : Blackwell Publishing Ltd

Water and environment journal 14 (2000), S. 0

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ISSN: 1747-6593

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Energietechnik

Notizen: Source control is regarded as a key principle in supporting concepts of sustainable management and integrated pollution control for diffuse non-point stormwater runoff, with infiltration procedures being a prime component of such source-control systems. The potential conflicts between the benefits of groundwater recharge and the risks to long-term groundwater quality uncertainties associated with infiltration disposal are considered. The long-term performance of a number of infiltration systems is reported in terms of their pollutant removal efficiencies, and the utility of an infiltration acceptability matrix approach is reviewed.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1111/j.1747-6593.2000.tb00222.x

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6

Digitale Medien

Transport and the Environment: Effects of Organic Pollutants on Water Quality (1997)

Ellis, J. B. ; Revitt, D. M. ; Llewellyn, N.

Oxford, UK : Blackwell Publishing Ltd

Water and environment journal 11 (1997), S. 0

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ISSN: 1747-6593

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Energietechnik

Notizen: The eighteenth report of the Royal Commission on Environmental Pollution made no reference to any potential environmental impacts resulting from runoff pollution associated with transport activities. This paper identifies the magnitude and extent of pollution associated with discharges from various transport sources and identifies solids, metals, hydrocarbons, herbicides and de-icing agents as the principal contaminants of environmental concern. The impacts of these pollutants on the receiving water are reviewed. They are primarily associated with highways which have a high traffic density, and herbicides are considered to be the only potential and widespread hazard to groundwaters. Highway and airport runoff are shown to have both acute and chronic effects on biotic diversity and organism mortality rates, although these effects appear to be largely confined to reaches immediately downstream from the discharge outfalls.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1111/j.1747-6593.1997.tb00112.x

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7

Digitale Medien

Photographic scoring of gingival overgrowth (2001)

Ellis, J. S. ; Seymour, R. A. ; Robertson, P. ; [weitere]

Copenhagen : Munksgaard International Publishers

Journal of clinical periodontology 28 (2001), S. 0

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ISSN: 1600-051X

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Medizin

Notizen: Background: A wide range of methods have been employed to determine the severity of gingival overgrowth resulting in uncertainty regarding the prevalence of the side-effect. There is no simple, non-invasive, objective, blind method for assessing gingival overgrowth.Aim: This article aims to describe a method which is suitable for use in large-scale population studies.Materials and Methods: Photographs were taken of the anterior, buccal gingivae and teeth of 925 patients medicated with calcium channel blockers. In addition, each patient was ascribed a clinical gingival overgrowth score. 100 patients had repeat photographs, and a further 10 patients had alginate impressions taken. The models were scored for severity of gingival overgrowth using a described technique. The slides were scored using a modification of this technique.Results: When photographic and study model scores were compared, photographic scores were consistently higher, and as a result, a photographic score of 38.6% was considered to represent a significant overgrowth. There was good agreement between clinically determined scores and photographic scores (κ=0.71).Conclusions: The results indicate that this method is suitable for large-scale population studies where it also has the advantage of providing a continuous scale of gingival changes for subsequent statistical analysis.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1111/j.1600-051X.2001.280112.x

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8

Digitale Medien

Risk factors for drug-induced gingival overgrowth (2000)

Seymour, R. A. ; Ellis, J. S. ; Thomason, J. M.

Copenhagen : Munksgaard International Publishers

Journal of clinical periodontology 27 (2000), S. 0

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ISSN: 1600-051X

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Medizin

Notizen: Background/Aims: Drug-induced gingival overgrowth remains a significant problem for the periodontologist. Many patients medicated with the drugs implicated in this unwanted effect experience significant, recurrent gingival problems that require repeated surgical excisions. In this review, we attempt to identify and quantify the various “risk factors” associated with both the development and expression of the drug-induced gingival changes.Method: The risk factors appraised include age, sex, drug variables, concomitant medication, periodontal variables and genetic factors. Elucidation of such factors may help to identify “at risk patients” and then develop appropriate treatment strategies.Results: Of the factors identified, the only one that can be affected by the periodontologist is the patents' periodontal condition. However, drug variables and concomitant medication do impact upon the expression of gingival overgrowth.Conclusion: The identificatioin of risk factors associated with both the prevalence and severity of drug-induced gingival overgrowth is important for all parties involved with this unwanted effect. Both periodontologist and patient have an important rôle to play in improving oral hygiene and gingival health. Likewise, there is always an opportinity to establish a close liaison between the patient's physician and the periodontologist to try and identify alternative drug regimens that can help reduce the impact of this unwanted effect.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1034/j.1600-051x.2000.027004217.x

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9

Digitale Medien

Prevalence of gingival overgrowth in transplant patients immunosuppressed with tacrolimus (2004)

Ellis, J. S. ; Seymour, R. A. ; Taylor, J. J. ; [weitere]

Oxford, UK : Munksgaard International Publishers

Journal of clinical periodontology 31 (2004), S. 0

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ISSN: 1600-051X

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Medizin

Notizen: Aims: The study aims to determine the prevalence and severity of gingival overgrowth in a group of adult organ transplant recipients immunosuppressed with tacrolimus in comparison with ciclosporin, and to examine various risk factors for the development of gingival overgrowth.Methods: Forty patients taking tacrolimus were compared with 197 ciclosporin patients. Demographic, pharmacological and periodontal data were recorded for all patients. Comparison between the groups was made using independent sample t-tests, χ2 statistic or Mann–Whitney test. The effects of risk variables on overgrowth severity were examined using forward and backward stepwise regression analysis.Results: Those taking tacrolimus had a significantly lower mean gingival overgrowth score (14.1%) compared with ciclosporin (22.4%). Fifteen percent of the tacrolimus group had clinically significant gingival overgrowth compared with 30% in the ciclosporin group (p=0.053).Conclusions: The prevalence and severity of gingival overgrowth is less in adult transplant patients taking tacrolimus compared with ciclosporin. Concomitant use of calcium channel blockers and previous medication with ciclosporin are significant risk factors for the presence and severity of gingival overgrowth. Patients who have alteration of their immunosuppressant from ciclosporin to tacrolimus may persist in demonstrating gingival overgrowth attributable to their ongoing therapy with calcium channel blockers.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1111/j.0303-6979.2004.00459.x

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10

Digitale Medien

Cardiovascular diseases and periodontology (2003)

Seymour, R. A. ; Preshaw, P. M. ; Thomason, J. M. ; [weitere]

Oxford, UK : Munksgaard International Publishers

Journal of clinical periodontology 30 (2003), S. 0

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ISSN: 1600-051X

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Medizin

Notizen: Background: Cardiovascular diseases represent a widespread heterogeneous group of conditions that have significant morbidity and mortality. The various diseases and their treatments can have an impact upon the periodontium and the delivery of periodontal care.Aim: In this paper we consider three main topics and explore their relationship to the periodontist and the provision of periodontal treatment.Method: The areas reviewed include the effect of cardiovascular drugs on the periodontium and management of patients with periodontal diseases; the risk of infective endocarditis arising from periodontal procedures; the inter-relationship between periodontal disease and coronary artery disease.Results and conclusions: Calcium-channel blockers and β-adrenoceptor blockers cause gingival overgrowth and tooth demineralisation, respectively. Evidence suggests that stopping anticoagulant therapy prior to periodontal procedures is putting patients at a greater risk of thromboembolic disorders compared to the risk of prolonged bleeding. The relationship between dentistry and infective endocarditis remains a controversial issue. It would appear that spontaneous bacteraemia arising from a patient's oral hygiene practices is more likely to be the cause of endocarditis than one-off periodontal procedures. The efficacy of antibiotic prophylaxis is uncertain (and unlikely to be proven), and the risk of death from penicillin appears to be greater than the risk of death arising from infective endocarditis. Finally, the association between periodontal disease and coronary artery disease has been explored and there seem to be many issues with respect to data handling interpretation. Many putative mechanisms have been suggested; however, these only further highlight the need for intervention studies.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1034/j.1600-051X.2003.00291.x

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