| 1. |
- Möller, Bengt, et al.
(författare)
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Lead Levels Determined in Swedish Permanent Teeth by Particle-Induced X-Ray Emission
- 1982
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Ingår i: Scandinavian Journal of Work, Environment and Health. - 0355-3140. ; 8:4, s. 267-272
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Tidskriftsartikel (refereegranskat)abstract
- The determination of lead in permanent teeth is a useful measure of past exposure in early childhood since these teeth are mineralized in early childhood. Particle-induced X-ray emission (PIXE) analysis has been shown to be a method with good applicability for the contamination-free analysis of elements heavier than calcium in dental hard tissues. The method is rapid and nondestructive. The purpose of this study, which used the PIXE technique, was to survey the average level of lead in the coronal dentin of permanent bicuspid teeth collected in three places representing Swedish urban and rural areas. In addition teeth from the New York City area were analyzed. The material comprised 165 teeth from Sweden and, for comparison, 14 teeth from New York City. The median value of lead in the Swedish teeth was 2.9 micrograms/g, a value indicating an insignificant influence from the environment in comparison to the New York teeth, for which the median value was 9.2 micrograms/g. There was however a statistically significant difference in the lead concentration of teeth from large and small Swedish cities; this finding may reflect different automobile traffic intensity.
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| 2. |
- Carlsson, Lars-Eric, et al.
(författare)
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Applicability of PIXE and XRF to Fast Drill Core Analysis in Air
- 1981
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Ingår i: Advances in X-Ray Analysis. ; 24, s. 313-321
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Tidskriftsartikel (refereegranskat)abstract
- The properties of particle-induced X-ray emission, PIXE, and secondary target mode X-ray fluorescence, XRF, applied to the analysis of unprepared drill cores in open air have been evaluated. Typical detection limits for elements heavier than Mg have been determined for a PIXE-system with an external 2.55 MeV proton beam and for an XRF-system with Ti, Mo and Tb secondary targets. These two systems were found to have similar detection limits for most elements in a typical geological sample. The heterogeneous composition of drill cores prevents the performance of accurate matrix corrections, though calculations using fundamental parameters show that in the PIXE analysis of elements heavier than Ca, these corrections are much less sensitive to variations in the matrix composition than in the XRF analysis.
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| 3. |
- Carlsson, Lars-Eric, et al.
(författare)
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Miljöanalys med hjälp av kärnfysikalisk teknik - PIXE
- 1981
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Ingår i: Ordo. - 0345-8970. ; 15:3, s. 3-8
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Tidskriftsartikel (refereegranskat)abstract
- Under de senaste tio åren har en känslig analysmetod för grundämnen utvecklats vid institutionen för kärnfysik vid LTH. Metoden kallas PIXE (Particle Induced X-ray Emisson) och medger att mycket små förekomster (109 – 1012 g) av grundämnen kanbestämmas i små prov. Metoden är snabb. Ett par minuters analys ger en samtidig bestämning av ett stort antal grundämnen. Analysmetoden används nu i ett stort antal laboratorier runt om i världen och har funnit tillämpning inom en rad olika områden såsom medicin, biologi, yrkes- och omgivningshygien, meteorologi, geologi samt arkeologi. I Lund har metoden huvudsakligen använts för omfattande studier av föroreningar i arbetsmiljö och yttre miljö, varför vi först redogör för vårt arbete inom dessa tillämpningsområden, varefter vi beskriver de fysikaliska principerna för analysmetoden och utvecklingsarbetet med den.
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| 4. |
- Carlsson, Lars-Eric, et al.
(författare)
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PIXE Analysis of Samples of Intermediate Thickness
- 1981
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 181:1-3, s. 179-183
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Tidskriftsartikel (refereegranskat)abstract
- A procedure for making accurate matrix corrections in PIXE analyses of samples of intermediate thickness has been developed. The transmission of a collimated X-ray beam through different parts of the sample is measured with a Si(Li) detector to determine the thickness and shape of the sample. Experiments have been performed using uniform polymer foils doped with known concentrations of different elements and with thicknesses ranging from 1.5 to 11 mg/cm2. The results from these samples indicate that the accuracy of the correction procedure is better than 5%. The correction procedure has been applied to, e.g., samples obtained in single orifice cascade impactors.
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| 5. |
- Carlsson, Lars-Eric, et al.
(författare)
-
Rapid Determination of Major and Trace Elements in Geological Material with Proton-Induced X-Ray and Gamma-Ray Emission
- 1981
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 181:1-3, s. 531-537
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Tidskriftsartikel (refereegranskat)abstract
- The simultaneous detection of proton-induced X-rays and gamma-rays enables rapid determination of both major and trace elements in thick homogeneous samples. Using protons of energy 2.55 MeV, the atomic numbers of the elements detectable with this technique were Z=3, 5, 9, 11–13 from gamma-ray analysis and Z=13–92 from X-ray analysis. Thick target concentrations were determined from a thoroughly made thin target calibration and from matrix-dependent conversion factors calculated from fundamental parameters. The major compositions of samples needed in these calculations are derived in an iterative procedure using the spectra recorded. The method proposed has been tested on six USGS rock standards. Detection limits for one of the standards are presented. Approximately 20 elements were detected in each sample 5 min irradiations. For elements well above their detection limits, the results are typically accurate to within 5%. The precision of repeated day-to-day analysis is about 2% (one standard deviation).
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| 6. |
- Eberhardt, Jacob, et al.
(författare)
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Trafikbullers inverkan på sömnen hos unga och äldre män
- 1980
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Trafikbullers inverkan på sömnen har undersökts medelst EEG-, EOG- och EMG-registreringar på sju unga män (21-27 år) och sex äldre män (63-74 år) i deras vanliga hemmiljö längs hårt trafikerade vägar (trafikintensitet cirka 450 fordonspassager med toppbullernivå överstigande 40 dB (A) per natt). Effekten av dämpning (cirka 10 dB (A)) av inomhusbullret genom montering av ljudisolerande plattor i fönsteröppningarna studerades. För unga män ökade andelen djup sömn (orto-3, -4) när ljudnivån i sovrummet sänktes med 10 dB (A). Dessutom ökade tiden i orto-23-sömn signifikant under nattens senare del. Effekten av bullerdämpningen för äldre män var huvudsakligen en minskning av insomningstiden samt en minskning av vakentiden under natten. Båda grupperna försökspersoner kom tidigare i djup orto-4-sömn under nätter med dämpning. För båda grupperna konstaterades en paradoxal ökning av antalet skift per natt mellan olika sömnstadier när ljudnivån sänktes. Likaså ökade antalet muskeltonushöjningar under nätter med dämpning. Det kunde med 95% signifikans påvisas att både sömnstadieskift till mindre djup sömn och muskeltonushöjningar förekommer som akuta svar på enstaka fordonspassager, dock är dessa akuta störningar så fåtaliga att de är försumbara jämfört med de sömnstadieskift och muskeltonushöjningar som inte är korrelerade till fordonspassager. En morgonenkät visade inte att unga män upplevde sömnen som bättre efter dämpning av ljudet i sovrummet, men de uppgav oftare att de inte hade vaknat någon gång under natten. Äldre män däremot uppgav att de sovit bättre, somnat lättare och känt sig mera utvilade efter nätter med dämpning.
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| 7. |
- Forslind, Bo, et al.
(författare)
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Elemental Analysis on Freeze-Dried Sections of Human Skin: Studies by Electron Microprobe and Particle Induced X-Ray Emission Analysis
- 1984
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Ingår i: Scanning Electron Microscopy. - 0586-5581. ; , s. 755-759
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Tidskriftsartikel (refereegranskat)abstract
- The possibility of using the proton microprobe (PMP) in the elemental analysis of dermatological material, under conditions where the spatial resolution can be restricted to a few micrometers, was demonstrated. Comparison with the electron microprobe (EMP) technique using duplicate sections from the same human skin biopsies revealed that the PMP and EMP techniques are complementary and yield closely corresponding elemental distributions for elements of dermatological interest. The concentrations of phosphorus and potassium were low in the dermis, high in the stratum basale and stratum spinosum, and decreased markedly in the stratum granulosum to a low level in the stratum corneum. The sulfur concentration was highest in the stratum corneum.
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| 8. |
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| 9. |
- Li, Hong-Kou, et al.
(författare)
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A PIXE System for Routine Longitudinal Scanning of Single Hair Strands
- 1984
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - 0168-583X. ; 3:1-3, s. 347-351
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Tidskriftsartikel (refereegranskat)abstract
- This article describes a PIXE system designed and constructed for routine longitudinal scanning of single hair strands. In constructing a PIXE system for trace elemental scans of single hair strands on a routine basis, a fairly intense beam has to be used but the heating damage must be kept to a minimum. The experimental conditions (charge integration, beam homogeneity etc.) have to be carefully controlled in order to give accurate PIXE results. The geometrical thickness of the hair at each point of the scan has to be determined and a qualitative knowledge of the elemental distribution over the cross section of the hair has to be provided for a proper interpretation of the PIXE results. In the present PIXE system the geometrical thickness of a hair strand at each point along the scan is determined by counting the number of backscattered protons simultaneously with the PIXE analysis, and a qualitative knowledge of the elemental distribution over the cross section of the hair is obtained through bombarding the hair at particular points with different proton energies.
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| 10. |
- Malmqvist, Klas, et al.
(författare)
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Proton and Electron Microprobe Analysis of Human Skin
- 1984
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms. - 0168-583X. ; 3:1-3, s. 611-617
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Tidskriftsartikel (refereegranskat)abstract
- In order to demonstrate the feasibility of the proton microprobe in the analysis of dermatological material when a spatial resolution of a few micrometres is sufficient and to compare it with the electron microprobe technique, duplicate sections of human skin have been analysed with both methods. A skin sample was obtained from each of three healthy volunteers. After cryosectioning (12 μm) and freeze-drying adjacent sections of each sample were scanned by the electron microprobe and the proton microprobe, respectively.
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