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Lubbe J, Simpson BRS, van Staden MJ, van Rooy MW. The operation of an ionization chamber with depleted gas for radioactivity measurement: Calibration procedure and utilising normalized manufacturer's radionuclide factors. Appl Radiat Isot 2021; 170:109633. [PMID: 33588201 DOI: 10.1016/j.apradiso.2021.109633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 01/28/2021] [Accepted: 01/29/2021] [Indexed: 11/29/2022]
Abstract
At the National Metrology Institute of South Africa (NMISA) absolute activity measurements of γ-emitting radionuclides are maintained for longevity on a secondary standard ionization chamber. Because the ionization chamber has lower gas pressure than that normally produced by the manufacturer, this paper focuses attention on explaining a normalization scheme devised to allow NMISA to make use of the manufacturer's supplied radionuclide calibration factors when necessary. The applicability of the procedure is justified through analysis of some results from a comprehensive simulation of the chamber undertaken in an independent study. Comparisons of the derived normalized calibration factors against those obtained through measurement at NMISA are made for a variety of radionuclides.
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Affiliation(s)
- J Lubbe
- Radioactivity Standards Section, NMISA, 15 Lower Hope Road, Rosebank, 7700, Cape Town, South Africa.
| | - B R S Simpson
- Radioactivity Standards Section, NMISA, 15 Lower Hope Road, Rosebank, 7700, Cape Town, South Africa
| | - M J van Staden
- Radioactivity Standards Section, NMISA, 15 Lower Hope Road, Rosebank, 7700, Cape Town, South Africa
| | - M W van Rooy
- Radioactivity Standards Section, NMISA, 15 Lower Hope Road, Rosebank, 7700, Cape Town, South Africa
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Lubbe J, Webner A, Potgieter A, Odendaal W, Cooper C, Lambrechts A. Metabolic surgery in South Africa: an initial academic hospital experience. S AFR J SURG 2019; 57:20-26. [PMID: 31342680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
BACKGROUND In South Africa, 42.0% of adult females and 13.5% of adult males are classified as obese, the highest recorded numbers in Sub-Saharan Africa. Metabolic surgery has been proven to be a safe and effective treatment, yet due to demand on government resources has only been performed to a limited extent in public hospitals. The aim of this study was to describe the safety and efficacy of performing metabolic surgery at a single academic hospital in South Africa. METHOD This was a single centre retrospective review of 57 metabolic surgery procedures performed from October 2011 to September 2017 at Tygerberg Hospital, Cape Town, South Africa. The primary outcome was safety including mortality and adverse events. Secondary outcomes included effect of surgery on weight and diabetes resolution. RESULTS A total of 57 patients underwent laparoscopic metabolic surgery, of which 44 (83.0%) were female with a mean age (standard deviation) of 42.8 (8.0) years. Fifty-six patients (98%) underwent Roux-and-Y gastric bypass and one (2%) had a sleeve gastrectomy performed. There were no mortalities and overall morbidity was 14.0%, with 3 (5.3%) classified as major and 5 (8.8%) as minor. The follow-up rate at 1 year was 100%. Mean preoperative body mass index (BMI) was 58.8 kg/m2, and comorbidities included hypertension (59.6%), Type 2 Diabetes (42.1%), and dyslipidaemia (36.8%). There were no conversions to open surgery and at one year the mean (95% confidence interval) percentage excess body mass index loss was 50.4% (44.0-56.8%). CONCLUSION Metabolic surgery can be performed safely in the public sector in South Africa, with short-term safety and efficacy outcomes comparable to international reports. Larger scale studies are needed to determine long-term outcomes and cost-effectiveness.
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Affiliation(s)
- J Lubbe
- Division of Surgery, Tygerberg Hospital and the University of Stellenbosch
| | - A Webner
- Division of Surgery, Tygerberg Hospital and the University of Stellenbosch
| | - A Potgieter
- Division of Surgery, Tygerberg Hospital and the University of Stellenbosch
| | - W Odendaal
- Division of Surgery, Tygerberg Hospital and the University of Stellenbosch
| | - C Cooper
- Division of Surgery, Tygerberg Hospital and the University of Stellenbosch
| | - A Lambrechts
- Division of Surgery, Tygerberg Hospital and the University of Stellenbosch
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Pommé S, Stroh H, Paepen J, Van Ammel R, Marouli M, Altzitzoglou T, Hult M, Kossert K, Nähle O, Schrader H, Juget F, Bailat C, Nedjadi Y, Bochud F, Buchillier T, Michotte C, Courte S, van Rooy M, van Staden M, Lubbe J, Simpson B, Fazio A, De Felice P, Jackson T, Van Wyngaardt W, Reinhard M, Golya J, Bourke S, Roy T, Galea R, Keightley J, Ferreira K, Collins S, Ceccatelli A, Unterweger M, Fitzgerald R, Bergeron D, Pibida L, Verheyen L, Bruggeman M, Vodenik B, Korun M, Chisté V, Amiot MN. Evidence against solar influence on nuclear decay constants. Phys Lett B 2016; 761:281-286. [PMID: 28057978 PMCID: PMC5207040 DOI: 10.1016/j.physletb.2016.08.038] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The hypothesis that proximity to the Sun causes variation of decay constants at permille level has been tested and disproved. Repeated activity measurements of mono-radionuclide sources were performed over periods from 200 days up to four decades at 14 laboratories across the globe. Residuals from the exponential nuclear decay curves were inspected for annual oscillations. Systematic deviations from a purely exponential decay curve differ from one data set to another and are attributable to instabilities in the instrumentation and measurement conditions. The most stable activity measurements of alpha, beta-minus, electron capture, and beta-plus decaying sources set an upper limit of 0.0006% to 0.008% to the amplitude of annual oscillations in the decay rate. Oscillations in phase with Earth's orbital distance to the Sun could not be observed within a 10-6 to 10-5 range of precision. There are also no apparent modulations over periods of weeks or months. Consequently, there is no indication of a natural impediment against sub-permille accuracy in half-life determinations, renormalisation of activity to a distant reference date, application of nuclear dating for archaeology, geo- and cosmochronology, nor in establishing the SI unit becquerel and seeking international equivalence of activity standards.
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Affiliation(s)
- S. Pommé
- European Commission, Joint Research Centre (JRC), Retieseweg 111, B-2440Geel, Belgium
| | - H. Stroh
- European Commission, Joint Research Centre (JRC), Retieseweg 111, B-2440Geel, Belgium
| | - J. Paepen
- European Commission, Joint Research Centre (JRC), Retieseweg 111, B-2440Geel, Belgium
| | - R. Van Ammel
- European Commission, Joint Research Centre (JRC), Retieseweg 111, B-2440Geel, Belgium
| | - M. Marouli
- European Commission, Joint Research Centre (JRC), Retieseweg 111, B-2440Geel, Belgium
| | - T. Altzitzoglou
- European Commission, Joint Research Centre (JRC), Retieseweg 111, B-2440Geel, Belgium
| | - M. Hult
- European Commission, Joint Research Centre (JRC), Retieseweg 111, B-2440Geel, Belgium
| | - K. Kossert
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany
| | - O. Nähle
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany
| | - H. Schrader
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany
| | - F. Juget
- Institut de Radiophysique, Lausanne (IRA), Switzerland
| | - C. Bailat
- Institut de Radiophysique, Lausanne (IRA), Switzerland
| | - Y. Nedjadi
- Institut de Radiophysique, Lausanne (IRA), Switzerland
| | - F. Bochud
- Institut de Radiophysique, Lausanne (IRA), Switzerland
| | - T. Buchillier
- Institut de Radiophysique, Lausanne (IRA), Switzerland
| | - C. Michotte
- Bureau International des Poids et Mesures (BIPM), Pavillon de Breteuil, 92310 Sèvres, France
| | - S. Courte
- Bureau International des Poids et Mesures (BIPM), Pavillon de Breteuil, 92310 Sèvres, France
| | - M.W. van Rooy
- Radioactivity Standards Laboratory (NMISA), 15 Lower Hope Road, Rosebank 7700, Cape Town, South Africa
| | - M.J. van Staden
- Radioactivity Standards Laboratory (NMISA), 15 Lower Hope Road, Rosebank 7700, Cape Town, South Africa
| | - J. Lubbe
- Radioactivity Standards Laboratory (NMISA), 15 Lower Hope Road, Rosebank 7700, Cape Town, South Africa
| | - B.R.S. Simpson
- Radioactivity Standards Laboratory (NMISA), 15 Lower Hope Road, Rosebank 7700, Cape Town, South Africa
| | - A. Fazio
- National Institute of Ionizing Radiation Metrology (ENEA), Casaccia Research Centre, Via Anguillarese, 301—S.M. Galeria I-00060 Roma, C.P. 2400, I-00100 Roma A.D., Italy
| | - P. De Felice
- National Institute of Ionizing Radiation Metrology (ENEA), Casaccia Research Centre, Via Anguillarese, 301—S.M. Galeria I-00060 Roma, C.P. 2400, I-00100 Roma A.D., Italy
| | - T.W. Jackson
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee, NSW 2232, Australia
| | - W.M. Van Wyngaardt
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee, NSW 2232, Australia
| | - M.I. Reinhard
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee, NSW 2232, Australia
| | - J. Golya
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee, NSW 2232, Australia
| | - S. Bourke
- Australian Nuclear Science and Technology Organisation (ANSTO), Locked Bag 2001, Kirrawee, NSW 2232, Australia
| | - T. Roy
- National Research Council of Canada (NRC), 1200 Montreal Road, Ottawa, ON, K1A0R6, Canada
| | - R. Galea
- National Research Council of Canada (NRC), 1200 Montreal Road, Ottawa, ON, K1A0R6, Canada
| | - J.D. Keightley
- National Physical Laboratory (NPL), Hampton Road, Teddington, Middlesex TW11 OLW, UK
| | - K.M. Ferreira
- National Physical Laboratory (NPL), Hampton Road, Teddington, Middlesex TW11 OLW, UK
| | - S.M. Collins
- National Physical Laboratory (NPL), Hampton Road, Teddington, Middlesex TW11 OLW, UK
| | - A. Ceccatelli
- Terrestrial Environment Laboratory, IAEA Environment Laboratories, Department of Nuclear Sciences and Applications, International Atomic Energy Agency (IAEA), Vienna International Centre, PO Box 100, 1400 Vienna, Austria
| | - M. Unterweger
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), 100 Bureau Dr., Gaithersburg, MD 20899-8462, USA
| | - R. Fitzgerald
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), 100 Bureau Dr., Gaithersburg, MD 20899-8462, USA
| | - D.E. Bergeron
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), 100 Bureau Dr., Gaithersburg, MD 20899-8462, USA
| | - L. Pibida
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), 100 Bureau Dr., Gaithersburg, MD 20899-8462, USA
| | - L. Verheyen
- Belgian Nuclear Research Centre (SCK·CEN), Boeretang 200, B-2400 Mol, Belgium
| | - M. Bruggeman
- Belgian Nuclear Research Centre (SCK·CEN), Boeretang 200, B-2400 Mol, Belgium
| | - B. Vodenik
- Jožef Stefan Institute (JSI), Jamova 39, 1000 Ljubljana, Slovenia
| | - M. Korun
- Jožef Stefan Institute (JSI), Jamova 39, 1000 Ljubljana, Slovenia
| | - V. Chisté
- CEA, LIST, Laboratoire National Henri Becquerel (LNHB), Bât. 602 PC 111, CEA-Saclay 91191 Gif-sur-Yvette cedex, France
| | - M.-N. Amiot
- CEA, LIST, Laboratoire National Henri Becquerel (LNHB), Bât. 602 PC 111, CEA-Saclay 91191 Gif-sur-Yvette cedex, France
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