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Andersson, Britt M.
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Publications (10 of 66) Show all publications
Shirdel, M., Bergdahl, I., Andersson, B. M., Wingfors, H., Sommar, J. & Liljelind, I. (2019). Passive personal air sampling of dust in a working environment: A pilot study. Journal of Occupational and Environmental Hygiene
Open this publication in new window or tab >>Passive personal air sampling of dust in a working environment: A pilot study
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2019 (English)In: Journal of Occupational and Environmental Hygiene, ISSN 1545-9624, E-ISSN 1545-9632Article in journal (Refereed) Epub ahead of print
Abstract [en]

The aim of this study was to make a preliminary evaluation of the University of North Carolina passive aerosol sampler (UNC sampler) for personal air sampling of particles. Nine personal air samplings of respirable fraction were conducted in an open-pit mine, with pairwise UNC samplers and a respirable cyclone mounted on the chest of workers. UNC samples were analyzed with scanning electron microscopy (SEM) and to some extent energy dispersive X-ray spectroscopy (EDS). Respirable cyclone filter samples were weighed. Correlations and particle elemental compositions were described. Microscopic imaging of the collection surface showed that the particles were heterogeneously deposited across the surface of the UNC sampler. Collected particles were shaped as gravel particles and the resulting particle size distribution in air showed a peak at ca. 3 µm aerodynamic diameter, similarly to what has previously been reported from the same mine. The elemental composition indicated mineral origin. All correlations between the airborne mass concentrations from UNC samplers and respirable cyclones (Pearson = 0.54 and Spearman = 0.43) and between pairs of parallel UNC samplers (Pearson = 0.55 and Spearman = 0.67) were weak. The UNC sampler mass concentrations were approximately 30 times higher than those measured with the respirable cyclone. In conclusion, the UNC sampler, when used for personal sampling in a mine, provides a reasonable particle size distribution and the deposited particles appeared to be of mineral origin and not from textile or skin but the approximately 30-fold overestimation of mass concentrations when comparing with respirable cyclone sampling indicates that further improvements are necessary. Positioning of the sampler may be critical and moving the UNC sampler from the chest to e.g. the top of a helmet might be an improvement. Grounding of the sampler in order to avoid static electricity might also be useful. The UNC sampler should continue to be researched for personal sampling, as passive sampling might become a useful alternative to more laborious sampling techniques.

Place, publisher, year, edition, pages
Taylor & Francis Group, 2019
Keywords
Area factor, UNC passive aerosol sampler, mesh factor, mineral, occupational exposure, respirable cyclone
National Category
Public Health, Global Health, Social Medicine and Epidemiology Occupational Health and Environmental Health
Identifiers
urn:nbn:se:umu:diva-162647 (URN)10.1080/15459624.2019.1648814 (DOI)31442106 (PubMedID)
Available from: 2019-08-26 Created: 2019-08-26 Last updated: 2019-09-02
Shirdel, M., Sommar, J. N., Andersson, B. M., Bergdahl, I. A., Wingfors, H. & Liljelind, I. E. (2018). Choosing the number of images and image position when analysing the UNC Passive Aerosol Sampler for occupational exposure assessment. Journal of Occupational and Environmental Hygiene, 15(11), 767-772
Open this publication in new window or tab >>Choosing the number of images and image position when analysing the UNC Passive Aerosol Sampler for occupational exposure assessment
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2018 (English)In: Journal of Occupational and Environmental Hygiene, ISSN 1545-9624, E-ISSN 1545-9632, Vol. 15, no 11, p. 767-772Article in journal (Refereed) Published
Abstract [en]

The University of North Carolina passive aerosol sampler (UNC sampler) could be an alternative when measuring occupational dust exposure, but the time required for microscopic imaging of the sampler needs to be reduced to make it more attractive. The aims of this study were to 1) characterise the effect on precision when reducing imaging, in order to shorten analysis time and 2) assess if the position of the images makes a difference. Eighty-eight samplers were deployed in different locations of an open pit mine. Sixty images were captured for each UNC sampler, covering 51% of its collection surface, using scanning electron microscopy. Bootstrapped samples were generated with different image combinations, to assess the within-sampler coefficient of variation (CVws) for different numbers of images. In addition, the particle concentration relative to the distance from the centre of the sampler was studied. Reducing the number of images collected from the UNC sampler led to up to 8.3% CVws for ten images when calculating respirable fraction. As the overall CV has previously been assessed to 36%, the additional contribution becomes minimal, increasing the overall CV to 37%. The mean concentrations of the images were modestly related to distance from the centre of the sampler. The CVws changed from 8.26% to 8.13% for ten images when applying rules for the image collection based on distance. Thus, the benefit of these rules on the precision is small and the images can therefore be chosen at random. In conclusion, reducing the number of images analysed from 60 to 10, corresponding to a reduction of the imaged sampling area from 51% to 8.5%, results in a negligible loss in precision for respirable fraction dust measurements in occupational environments.

Place, publisher, year, edition, pages
Taylor & Francis, 2018
Keywords
Dust particles, PM10, PM2.5, occupational hygienist, passive sampling, respirable fraction
National Category
Public Health, Global Health, Social Medicine and Epidemiology Environmental Sciences
Identifiers
urn:nbn:se:umu:diva-152114 (URN)10.1080/15459624.2018.1508875 (DOI)000451621900002 ()30111275 (PubMedID)
Available from: 2018-09-27 Created: 2018-09-27 Last updated: 2018-12-19Bibliographically approved
Shirdel, M., Andersson, B. M., Bergdahl, I., Sommar, J. N., Wingfors, H. & Liljelind, I. E. (2018). Improving the UNC passive aerosol sampler model based on comparison with commonly used aerosol sampling methods. Annals of Work Exposures and Health, 62(3), 328-338
Open this publication in new window or tab >>Improving the UNC passive aerosol sampler model based on comparison with commonly used aerosol sampling methods
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2018 (English)In: Annals of Work Exposures and Health, ISSN 2398-7308, Vol. 62, no 3, p. 328-338Article in journal (Refereed) Published
Abstract [en]

Objectives: In an occupational environment, passive sampling could be an alternative to active sampling with pumps for sampling of dust. One passive sampler is the University of North Carolina passive aerosol sampler (UNC sampler). It is often analysed by microscopic imaging. Promising results have been shown for particles above 2.5 µm, but indicate large underestimations for PM2.5. The aim of this study was to evaluate, and possibly improve, the UNC sampler for stationary sampling in a working environment.

Methods: Sampling was carried out at 8-h intervals during 24 h in four locations in an open pit mine with UNC samplers, respirable cyclones, PM10 and PM2.5 impactors, and an aerodynamic particle sizer (APS). The wind was minimal. For quantification, two modifications of the UNC sampler analysis model, UNC sampler with hybrid model and UNC sampler with area factor, were compared with the original one, UNC sampler with mesh factor derived from wind tunnel experiments. The effect of increased resolution for the microscopic imaging was examined.

Results: Use of the area factor and a higher resolution eliminated the underestimation for PM10 and PM2.5. The model with area factor had the overall lowest deviation versus the impactor and the cyclone. The intraclass correlation (ICC) showed that the UNC sampler had a higher precision and better ability to distinguish between different exposure levels compared to the cyclone (ICC: 0.51 versus 0.24), but lower precision compared to the impactor (PM10: 0.79 versus 0.99; PM2.5: 0.30 versus 0.45). The particle size distributions as calculated from the different UNC sampler analysis models were visually compared with the distributions determined by APS. The distributions were obviously different when the UNC sampler with mesh factor was used but came to a reasonable agreement when the area factor was used.

Conclusions: High resolution combined with a factor based on area only, results in no underestimation of small particles compared to impactors and cyclones and a better agreement with the APS’s particle size distributions. The UNC sampler had lower precision than the impactors, but higher than the respirable cyclone. The UNC sampler with area factor could be used for PM2.5, PM10 and respirable fraction measurements in this working environment without wind.

Place, publisher, year, edition, pages
Oxford University Press, 2018
Keywords
inorganic dust, mesh factor, PM10, PM2.5, respirable fraction, UNC passive aerosol sampler, working environment
National Category
Occupational Health and Environmental Health
Identifiers
urn:nbn:se:umu:diva-145698 (URN)10.1093/annweh/wxx110 (DOI)000432804600008 ()29300818 (PubMedID)
Available from: 2018-03-14 Created: 2018-03-14 Last updated: 2018-06-26Bibliographically approved
Shirdel, M., Wingfors, H., Andersson, B. M., Sommar, J. N., Bergdahl, I. A. & Liljelind, I. E. (2017). A pilot study: the UNC passive aerosol sampler in a working environment. Annals of Work Exposures and Health, 61(8), 1029-1034
Open this publication in new window or tab >>A pilot study: the UNC passive aerosol sampler in a working environment
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2017 (English)In: Annals of Work Exposures and Health, ISSN 2398-7308, Vol. 61, no 8, p. 1029-1034Article in journal (Refereed) Published
Abstract [en]

Objectives: Dust is generally sampled on a filter using air pumps, but passive sampling could be a cost-effective alternative. One promising passive sampler is the University of North Carolina passive aerosol sampler (UNC sampler). The aim of this study is to characterize and compare the UNC sampler’s performance with PM10 and PM2.5 impactors in a working environment.

Methods: Area sampling was carried out at different mining locations using UNC samplers in parallel with PM2.5 and PM10 impactors. Two different collection surfaces, polycarbonate (PC) and carbon tabs (CT), were employed for the UNC sampling. Sampling was carried out for 4–25 hours.

Results: The UNC samplers underestimated the concentrations compared to PM10 and PM2.5 impactor data. At the location with the highest aerosol concentration, the time-averaged mean of PC showed 24% and CT 35% of the impactor result for PM2.5. For PM10, it was 39% with PC and 58% with CT. Sample blank values differed between PC and CT. For PM2.5, PC blank values were ~7 times higher than those of CT, but only 1.8 times higher for PM10. The blank variations were larger for PC than for CT.

Conclusions: Particle mass concentrations appear to be underestimated by the UNC sampler compared to impactors, more so for PM2.5 than for PM10. CT may be preferred as a collection surface because the blank values were lower and less variable than for PC. Future validations in the working environment should include respirable dust sampling.

Place, publisher, year, edition, pages
Oxford University Press, 2017
Keywords
inorganic dust, PM2.5, PM10, scanning electron microscopy, UNC passive aerosol sampler, working environment
National Category
Occupational Health and Environmental Health
Identifiers
urn:nbn:se:umu:diva-140539 (URN)10.1093/annweh/wxx067 (DOI)000417608500013 ()29028256 (PubMedID)
Available from: 2017-10-13 Created: 2017-10-13 Last updated: 2018-06-09Bibliographically approved
Åstrand, A., Andersson, B., Jalkanen, V., Börje, L., Anders, B. & Lindahl, O. (2017). Prostate cancer detection with a tactile resonance sensor: measurement considerations and clinical setup. Sensors, 17(11), Article ID 2453.
Open this publication in new window or tab >>Prostate cancer detection with a tactile resonance sensor: measurement considerations and clinical setup
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2017 (English)In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 17, no 11, article id 2453Article in journal (Refereed) Published
Abstract [en]

Tumors in the human prostate are usually stiffer compared to surrounding non-malignant glandular tissue, and tactile resonance sensors measuring stiffness can be used to detect prostate cancer. To explore this further, we used a tactile resonance sensor system combined with a rotatable sample holder where whole surgically removed prostates could be attached to detect tumors on, and beneath, the surface ex vivo. Model studies on tissue phantoms made of silicone and porcine tissue were performed. Finally, two resected human prostate glands were studied. Embedded stiff silicone inclusions placed 4 mm under the surface could be detected in both the silicone and biological tissue models, with a sensor indentation of 0.6 mm. Areas with different amounts of prostate cancer (PCa) could be distinguished from normal tissue (p < 0.05), when the tumor was located in the anterior part, whereas small tumors located in the dorsal aspect were undetected. The study indicates that PCa may be detected in a whole resected prostate with an uneven surface and through its capsule. This is promising for the development of a clinically useful instrument to detect prostate cancer during surgery.

Place, publisher, year, edition, pages
Switzerland: MDPI AG, 2017
Keywords
tissue stiffness, resonance sensor, tactile sensor, prostate cancer, piezoelectric sensor
National Category
Medical Laboratory and Measurements Technologies
Identifiers
urn:nbn:se:umu:diva-141158 (URN)10.3390/s17112453 (DOI)000416790500015 ()
Available from: 2017-10-26 Created: 2017-10-26 Last updated: 2018-06-09Bibliographically approved
Shirdel, M., Andersson, B., Liljelind, I., Nilsson Sommar, J., Håkan, W. & Bergdahl, I. A. (2017). Should one really use wind tunnel experiments for a passive sampler?. In: : . Paper presented at NOSA Aerosol Symposium 2017, Lund.
Open this publication in new window or tab >>Should one really use wind tunnel experiments for a passive sampler?
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2017 (English)Conference paper, Poster (with or without abstract) (Other academic)
National Category
Occupational Health and Environmental Health
Identifiers
urn:nbn:se:umu:diva-140583 (URN)
Conference
NOSA Aerosol Symposium 2017, Lund
Available from: 2017-10-13 Created: 2017-10-13 Last updated: 2018-06-09
Åstrand, A. P., Andersson, B. M., Jalkanen, V. & Lindahl, O. A. (2015). Initial Measurements on Whole Human Prostate ex vivo with a Tactile Resonance Sensor in Order to Detect Prostate Cancer. In: Henrik Mindedal, Mikael Persson (Ed.), 16th Nordic-Baltic Conference on Biomedical Engineering: 16. NBC & 10. MTD 2014 joint conferences. October 14-16, 2014, Gothenburg, Sweden. Paper presented at 16th Nordic-Baltic Conference on Biomedical Engineering October 14-16, 2014, Gothenburg, Sweden (pp. 120-123). Springer International Publishing
Open this publication in new window or tab >>Initial Measurements on Whole Human Prostate ex vivo with a Tactile Resonance Sensor in Order to Detect Prostate Cancer
2015 (English)In: 16th Nordic-Baltic Conference on Biomedical Engineering: 16. NBC & 10. MTD 2014 joint conferences. October 14-16, 2014, Gothenburg, Sweden / [ed] Henrik Mindedal, Mikael Persson, Springer International Publishing , 2015, p. 120-123Conference paper, Published paper (Refereed)
Abstract [en]

Prostate cancer (PCa) is the most common form of cancer among the male population in Europe and the USA. PCa can be suspected by a blood test for a specific prostate antigen, a PSA-test, followed by a digital rectal examination (DRE). The objective with the DRE is to investigate the presence of stiff nodules on the prostate. Stiff nodules can indicate PCa and biopsies are taken from the suspicious parts of the prostate using guidance of a transrectal ultrasound. Microscopic evaluation of the biopsies is used for final diagnosis. Superficial tumor growth on, and beneath the surface of the gland is of special interest as it suggests that the cancer has spread to other parts of the body.

Tactile resonance sensors can be used to distinguish between areas of different stiffness in soft tissue. The aim was to detect tumors on, and beneath the surface of a whole human prostate ex vivo.

A tactile resonance sensor system (TRSS) based on a piezoelectric resonance sensor and a force sensor has been used to detect areas with increased stiffness in soft tissue. The TRSS has a rotatable sample holder for measurements on spherical shaped samples. Stiffness measurements were made on samples of porcine muscle tissue with embedded stiff silicone nodules placed under the surface. Further measurements were made on a resected whole human prostate with PCa.

The results showed that through the measured stiffness parameter, the stiff silicone nodules placed down to 4 mm under the surface could be detected. The measurements on the prostate showed that elevated values of the stiffness parameter correlated (p < 0.05) with areas in the anterior of the prostate where cancer tumors were detected by histopathological evaluation. The tumors were significantly stiffer than the healthy tissue in the dorsal region.

The results are promising for further development of a clinically useful instrument to detect superficial PCa.

Place, publisher, year, edition, pages
Springer International Publishing, 2015
Series
IFMBE Proceedings, ISSN 1680-0737 ; 48
Keywords
Prostate cancer, Tissue stiffness, Resonance sensors
National Category
Medical Engineering Medical Laboratory and Measurements Technologies
Identifiers
urn:nbn:se:umu:diva-97279 (URN)10.1007/978-3-319-12967-9_33 (DOI)000347893000033 ()978-3-319-12966-2 (ISBN)978-3-319-12967-9 (ISBN)
Conference
16th Nordic-Baltic Conference on Biomedical Engineering October 14-16, 2014, Gothenburg, Sweden
Available from: 2014-12-12 Created: 2014-12-12 Last updated: 2018-06-07Bibliographically approved
Shirdel, M., Håkan, W., Andersson, B. & Liljelind, I. (2014). Comparing the UNC passive sampler to particle counters in the swedish mining industry. In: : . Paper presented at Airmon15‐19 June 2014 Marseille, France.
Open this publication in new window or tab >>Comparing the UNC passive sampler to particle counters in the swedish mining industry
2014 (English)Conference paper, Oral presentation with published abstract (Other academic)
National Category
Occupational Health and Environmental Health
Identifiers
urn:nbn:se:umu:diva-140582 (URN)
Conference
Airmon15‐19 June 2014 Marseille, France
Available from: 2017-10-13 Created: 2017-10-13 Last updated: 2018-06-09
Jonsson, U. G., Lindahl, O. A. & Andersson, B. M. (2014). Modeling the high-frequency complex modulus of a silicone rubber using standing lamb waves and an inverse finite element method. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 61(12), 2106-2120
Open this publication in new window or tab >>Modeling the high-frequency complex modulus of a silicone rubber using standing lamb waves and an inverse finite element method
2014 (English)In: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, ISSN 0885-3010, E-ISSN 1525-8955, Vol. 61, no 12, p. 2106-2120Article in journal (Refereed) Published
Abstract [en]

To gain an understanding of the high-frequency elastic properties of silicone rubber, a finite element model of a cylindrical piezoelectric element, in contact with a silicone rubber disk, was constructed. The frequency dependent elastic modulus of the silicone rubber was modeled by a four parameter fractional derivative viscoelastic model in the 100 kHz to 250 kHz frequency range. The calculations were carried out in the range of the first radial resonance frequency of the sensor. At the resonance, the hyperelastic effect of the silicone rubber was modeled by a hyperelastic compensating function. The calculated response was matched to the measured response by using the transitional peaks in the impedance spectrum that originates from the switching of standing Lamb wave modes in the silicone rubber. To validate the results, the impedance responses of three 5 mm thick silicone rubber disks, with different radial lengths, were measured. The calculated and measured transitional frequencies have been compared in detail. The comparison showed very good agreement, with average relative differences of 0.7 %, 0.6 %, and 0.7 % for the silicone rubber samples with radial lengths of 38.0 mm, 21.4 mm, and 11.0 mm, respectively. The average, complex, elastic modulus of the samples were: (0.97 + 0.009i) GPa at 100 kHz and (0.97 + 0.005i) GPa at 250 kHz.

Place, publisher, year, edition, pages
IEEE Press, 2014
Keywords
piezoelectric, silicone rubber, impedance, resonance, lamb waves, phantom
National Category
Medical Laboratory and Measurements Technologies Electrical Engineering, Electronic Engineering, Information Engineering Fluid Mechanics and Acoustics
Research subject
Electronics
Identifiers
urn:nbn:se:umu:diva-88214 (URN)10.1109/TUFFC.2014.006471 (DOI)000345944300017 ()
Available from: 2014-04-28 Created: 2014-04-28 Last updated: 2018-06-07Bibliographically approved
Jonsson, U. ., Andersson, B. M. & Lindahl, O. A. (2013). A FEM-Based Method Using Harmonic Overtones to Determine the Effective Elastic, Dielectric, and Piezoelectric Parameters of Freely Vibrating Thick Piezoelectric Disks. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 60(1), 243-255
Open this publication in new window or tab >>A FEM-Based Method Using Harmonic Overtones to Determine the Effective Elastic, Dielectric, and Piezoelectric Parameters of Freely Vibrating Thick Piezoelectric Disks
2013 (English)In: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, ISSN 0885-3010, E-ISSN 1525-8955, Vol. 60, no 1, p. 243-255Article in journal (Refereed) Published
Abstract [en]

To gain an understanding of the electroelasticproperties of tactile piezoelectric sensors used in the characterizationof soft tissue, the frequency-dependent electric impedanceresponse of thick piezoelectric disks has been calculatedusing finite element modeling. To fit the calculated to the measuredresponse, a new method was developed using harmonicovertones for tuning of the calculated effective elastic, piezoelectric,and dielectric parameters. To validate the results, theimpedance responses of 10 piezoelectric disks with diameterto-thickness ratios of 20, 6, and 2 have been measured from10 kHz to 5 MHz. A two-dimensional, general purpose finiteelement partial differential equation solver with adaptive meshingcapability run in the frequency-stepped mode, was used.The equations and boundary conditions used by the solver arepresented. Calculated and measured impedance responses arepresented, and resonance frequencies have been compared indetail. The comparison shows excellent agreement, with averagerelative differences in frequency of 0.27%, 0.19%, and0.54% for the samples with diameter-to-thickness ratios of 20,6, and 2, respectively. The method of tuning the effective elastic,piezoelectric, and dielectric parameters is an importantstep toward a finite element model that describes the propertiesof tactile sensors in detail.

Place, publisher, year, edition, pages
New York: IEEE Ultrasonics, Ferroelectrics, and Frequency Control Society, 2013
Keywords
piezoelectric, impedance, resonance, effective parameter, disk
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electronics
Identifiers
urn:nbn:se:umu:diva-63830 (URN)10.1109/TUFFC.2013.2555 (DOI)000314369700024 ()23287929 (PubMedID)
Available from: 2013-01-25 Created: 2013-01-08 Last updated: 2018-06-08Bibliographically approved
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