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Wagri NK, Carlborg M, Eriksson M, Ma C, Broström M, Andersson BM. High temperature interactions between K-rich biomass ash and MgO-based refractories. Ann Ital Chir 2023. [DOI: 10.1016/j.jeurceramsoc.2023.01.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Mejtoft T, Lindahl O, Öhberg F, Pommer L, Jonzén K, Andersson BM, Eklund A, Wåhlin A, Hallberg P. Medtech innovation guide: an empiric model to support medical technology innovation. Health Technol 2022. [DOI: 10.1007/s12553-022-00689-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
AbstractInnovation has become increasingly important for most industries to cope with rapid technological changes as well as changing societal needs. Even though there are many sectors with specific needs when it comes to supporting innovation, the medical technology sector is facing several unique challenges that both increases the lead-time from idea to finished product and decreases the number of innovations that are developed. This paper presents a proposed innovation guide that has been developed and evaluated as a support for the innovation process within medical technology research. The guide takes the unique characteristics of the medical technology sector into account and serves as a usable guide for the innovator. The complete guide contains both a structure for the process and a usable web application to support the journey from idea to finished products and services. The paper also includes a new readiness level, Sect. 4.2 to provide support both when developing and determining the readiness for clinical implementation of a medical technology innovation.
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Shirdel M, Bergdahl IA, Andersson BM, Wingfors H, Sommar JN, Liljelind IE. Passive personal air sampling of dust in a working environment-A pilot study. J Occup Environ Hyg 2019; 16:675-684. [PMID: 31442106 DOI: 10.1080/15459624.2019.1648814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
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.
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Affiliation(s)
- Mariam Shirdel
- Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University , Umeå , Sweden
| | - Ingvar A Bergdahl
- Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University , Umeå , Sweden
| | - Britt M Andersson
- Department of Applied Physics and Electronics, Umeå University , Umeå , Sweden
| | - Håkan Wingfors
- Swedish Defence Research Agency, CBRN Defence & Security Division , Cementvägen, Umeå , Sweden
| | - Johan N Sommar
- Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University , Umeå , Sweden
| | - Ingrid E Liljelind
- Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University , Umeå , Sweden
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Shirdel M, Sommar JN, Andersson BM, Bergdahl IA, Wingfors H, Liljelind IE. Choosing the number of images and image position when analyzing the UNC Passive Aerosol Sampler for occupational exposure assessment. J Occup Environ Hyg 2018; 15:767-772. [PMID: 30111275 DOI: 10.1080/15459624.2018.1508875] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
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) characterize 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 center of the sampler was studied. Reducing the number of images collected from the UNC sampler led to up to 8.3% CVws for 10 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 center of the sampler. The CVws changed from 8.26% to 8.13% for 10 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 analyzed 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.
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Affiliation(s)
- M Shirdel
- a Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine , Umeå University , Umeå, Sweden
| | - J N Sommar
- a Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine , Umeå University , Umeå, Sweden
| | - B M Andersson
- b Department of Applied Physics and Electronics , Umeå University , Umeå, Sweden
| | - I A Bergdahl
- a Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine , Umeå University , Umeå, Sweden
| | - H Wingfors
- c Swedish Defence Research Agency CBRN Defence & Security Division , Umeå , Sweden
| | - I E Liljelind
- a Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine , Umeå University , Umeå, Sweden
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Shirdel M, Andersson BM, Bergdahl IA, Sommar JN, Wingfors H, Liljelind IE. Improving the UNC Passive Aerosol Sampler Model Based on Comparison with Commonly Used Aerosol Sampling Methods. Ann Work Expo Health 2018; 62:328-338. [PMID: 29300818 PMCID: PMC5873525 DOI: 10.1093/annweh/wxx110] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 12/01/2017] [Indexed: 11/12/2022] Open
Abstract
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.
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Affiliation(s)
- Mariam Shirdel
- Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - Britt M Andersson
- Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden
| | - Ingvar A Bergdahl
- Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - Johan N Sommar
- Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - Håkan Wingfors
- CBRN Defence & Security Division, Swedish Defence Research Agency, Cementvägen, Umeå, Sweden
| | - Ingrid E Liljelind
- Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
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Åstrand AP, Andersson BM, Jalkanen V, Ljungberg B, Bergh A, Lindahl OA. Prostate Cancer Detection with a Tactile Resonance Sensor-Measurement Considerations and Clinical Setup. Sensors (Basel) 2017; 17:s17112453. [PMID: 29072592 PMCID: PMC5713103 DOI: 10.3390/s17112453] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/16/2017] [Accepted: 10/24/2017] [Indexed: 12/11/2022]
Abstract
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.
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Affiliation(s)
- Anders P Åstrand
- Department of Applied Physics and Electronics, Umeå University, SE-90187 Umeå, Sweden.
- Centre for Biomedical Engineering and Physics, Umeå University, SE-90187 Umeå, Sweden.
| | - Britt M Andersson
- Department of Applied Physics and Electronics, Umeå University, SE-90187 Umeå, Sweden.
- Centre for Biomedical Engineering and Physics, Umeå University, SE-90187 Umeå, Sweden.
| | - Ville Jalkanen
- Department of Applied Physics and Electronics, Umeå University, SE-90187 Umeå, Sweden.
- Centre for Biomedical Engineering and Physics, Umeå University, SE-90187 Umeå, Sweden.
| | - Börje Ljungberg
- Department of Surgical and Perioperative Science, Urology and Andrology, Umeå University, SE-90187 Umeå, Sweden.
| | - Anders Bergh
- Department of Medical Biosciences, Pathology, Umeå University, SE-90187 Umeå, Sweden.
| | - Olof A Lindahl
- Centre for Biomedical Engineering and Physics, Umeå University, SE-90187 Umeå, Sweden.
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, SE-90187 Umeå, Sweden.
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Shirdel M, Wingfors H, Andersson BM, Sommar JN, Bergdahl IA, Liljelind IE. A Pilot Study: The UNC Passive Aerosol Sampler in a Working Environment. Ann Work Expo Health 2017; 61:1029-1034. [PMID: 29028256 PMCID: PMC6824523 DOI: 10.1093/annweh/wxx067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 07/18/2017] [Indexed: 11/13/2022] Open
Abstract
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.
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Affiliation(s)
- Mariam Shirdel
- Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University, 901 87, Umeå, Sweden
| | - Håkan Wingfors
- Swedish Defence Research Agency, CBRN Defence and Security Division, Cementvägen 20, SE-901 82, Umeå, Sweden
| | - Britt M Andersson
- Department of Applied Physics and Electronics, Umeå University, SE-901 87, Umeå, Sweden
| | - Johan N Sommar
- Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University, 901 87, Umeå, Sweden
| | - Ingvar A Bergdahl
- Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University, 901 87, Umeå, Sweden
| | - Ingrid E Liljelind
- Occupational and Environmental Medicine, Department of Public Health and Clinical Medicine, Umeå University, 901 87, Umeå, Sweden
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Åstrand AP, Andersson BM, Jalkanen V, Lindahl OA. Initial Measurements on Whole Human Prostate ex vivo with a Tactile Resonance Sensor in Order to Detect Prostate Cancer. IFMBE Proceedings 2015. [DOI: 10.1007/978-3-319-12967-9_33] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Åstrand AP, Jalkanen V, Andersson BM, Lindahl OA. Detection of Stiff Nodules Embedded in Soft Tissue Phantoms, Mimicking Cancer Tumours, Using a Tactile Resonance Sensor. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/jbise.2014.74022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Jalkanen V, Andersson BM, Bergh A, Ljungberg B, Lindahl OA. Indentation loading response of a resonance sensor--discriminating prostate cancer and normal tissue. J Med Eng Technol 2013; 37:416-23. [PMID: 23978075 DOI: 10.3109/03091902.2013.824510] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Prostate cancer is the most common type of cancer among men worldwide. Mechanical properties of prostate tissue are promising for distinguishing prostate cancer from healthy prostate tissue. The aim was to investigate the indentation loading response of a resonance sensor for discriminating prostate cancer tissue from normal tissue. Indentation measurements were done on prostate tissue specimens ex vivo from 10 patients from radical prostatectomy. The measurement areas were analysed using standard histological methods. The stiffness parameter was linearly dependent on the loading force (average R(2 )= 0.90) and an increased loading force caused a greater stiffness contrast of prostate cancer vs normal tissue. The accuracy of the stiffness contrast was assessed by the ROC curve with the area under the curve being 0.941 for a loading force of 12.8 mN. The results are promising for the development of a resonance sensor instrument for detecting prostate cancer.
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Åstrand AP, Jalkanen V, Andersson BM, Lindahl OA. Contact angle and indentation velocity dependency for a resonance sensor—Evaluation on soft tissue silicone models. J Med Eng Technol 2013; 37:185-96. [DOI: 10.3109/03091902.2013.773097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Jonsson UG, Andersson BM, Lindahl OA. A FEM-based method using harmonic overtones to determine the effective elastic, dielectric, and piezoelectric parameters of freely vibrating thick piezoelectric disks. IEEE Trans Ultrason Ferroelectr Freq Control 2013; 60:243-255. [PMID: 23287929 DOI: 10.1109/tuffc.2013.2555] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
To gain an understanding of the electroelastic properties of tactile piezoelectric sensors used in the characterization of soft tissue, the frequency-dependent electric impedance response of thick piezoelectric disks has been calculated using finite element modeling. To fit the calculated to the measured response, a new method was developed using harmonic overtones for tuning of the calculated effective elastic, piezoelectric, and dielectric parameters. To validate the results, the impedance responses of 10 piezoelectric disks with diameter-to-thickness ratios of 20, 6, and 2 have been measured from 10 kHz to 5 MHz. A two-dimensional, general purpose finite element partial differential equation solver with adaptive meshing capability run in the frequency-stepped mode, was used. The equations and boundary conditions used by the solver are presented. Calculated and measured impedance responses are presented, and resonance frequencies have been compared in detail. The comparison shows excellent agreement, with average relative differences in frequency of 0.27%, 0.19%, and 0.54% 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 important step toward a finite element model that describes the properties of tactile sensors in detail.
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Affiliation(s)
- Ulf G Jonsson
- Department of Applied Physics and Electronics and the Centre for Biomedical Engineering and Physics, Umea University, Umea, Sweden.
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Tonpheng B, Yu J, Andersson BM, Andersson O. Tensile Strength and Young’s Modulus of Polyisoprene/Single-Wall Carbon Nanotube Composites Increased by High Pressure Cross-linking. Macromolecules 2010. [DOI: 10.1021/ma101484e] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Junchun Yu
- Department of Physics, Umeå University, 901 87 Umeå, Sweden
| | - Britt M Andersson
- Department of Applied Physics and Electronics, Umeå University, 901 87 Umeå, Sweden
| | - Ove Andersson
- Department of Physics, Umeå University, 901 87 Umeå, Sweden
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Lindberg PL, Andersson BM, Bergh A, Ljungberg B, Lindahl OA. An image analysis method for prostate tissue classification: preliminary validation with resonance sensor data. J Med Eng Technol 2009; 33:18-24. [PMID: 19116850 DOI: 10.1080/03091900801945200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Resonance sensor systems have been shown to be able to distinguish between cancerous and normal prostate tissue, in vitro. The aim of this study was to improve the accuracy of the tissue determination, to simplify the tissue classification process with computerized morphometrical analysis, to decrease the risk of human errors, and to reduce the processing time. In this article we present our newly developed computerized classification method based on image analysis. In relation to earlier resonance sensor studies we increased the number of normal prostate tissue classes into stroma, epithelial tissue, lumen and stones. The linearity between the impression depth and tissue classes was calculated using multiple linear regression (R(2) = 0.68, n = 109, p < 0.001) and partial least squares (R(2) = 0.55, n = 109, p < 0.001). Thus it can be concluded that there existed a linear relationship between the impression depth and the tissue classes. The new image analysis method was easy to handle and decreased the classification time by 80%.
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Affiliation(s)
- P L Lindberg
- Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden
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Jalkanen V, Andersson BM, Bergh A, Ljungberg B, Lindahl OA. Explanatory models for a tactile resonance sensor system—elastic and density-related variations of prostate tissuein vitro. Physiol Meas 2008; 29:729-45. [DOI: 10.1088/0967-3334/29/7/003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Jalkanen V, Andersson BM, Bergh A, Ljungberg B, Lindahl OA. Spatial variations in prostate tissue histology as measured by a tactile resonance sensor. Physiol Meas 2007; 28:1267-81. [PMID: 17906393 DOI: 10.1088/0967-3334/28/10/011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In recent years, tactile sensors based on piezoelectric resonance sensor technology have been used for medical diagnosis where the sensor's stiffness-measuring properties can reflect tissue pathology. The change in the frequency of the resonating system and the change in force when contact is made with tissue are used as a stiffness parameter. Earlier stiffness measurements of prostate tissue in vitro demonstrate variations related to tissue composition. In this study, measured stiffness from two human prostate specimens was compared to histological composition of prostate tissue below and around the measurement points. Tissue stiffness was measured with the resonance sensor system. Tissue composition was measured at four different depths in the tissue specimen using a microscopic-image-based morphometrical method. With this method, the proportion of tissue types was determined at the points of intersections in a circular grid on the images representing each measurement point. Numerical values were used for weighting the tissue proportions at different depths in the tissue specimen. For an impression depth of 1.0 mm, the sensing depth in this study was estimated to be 3.5-5.5 mm. Stiffness variations due to horizontal tissue variations were investigated by studying the dependence of the size of the circular grid area relative to the contact area of the sensor tip. The sensing area (grid radius) was estimated to be larger than the contact area (contact radius) between the sensor tip and the tissue. Thus, the sensor tip registers spatial variations in prostate tissue histology, both directly below and lateral to the tip itself. These findings indicate that tumours around the sensor tip could be detected, which in turn supports the idea of a future resonance-sensor-based clinical device for detecting tumours and for guiding biopsies.
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Affiliation(s)
- Ville Jalkanen
- Department of Applied Physics and Electronics, Umeå University, SE-90187 Umeå, Sweden.
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Jalkanen V, Andersson BM, Bergh A, Ljungberg B, Lindahl OA. Resonance sensor measurements of stiffness variations in prostate tissuein vitro—a weighted tissue proportion model. Physiol Meas 2006; 27:1373-86. [PMID: 17135706 DOI: 10.1088/0967-3334/27/12/009] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Prostate cancer is the most common type of cancer in men in Europe and the US. The methods to detect prostate cancer are still precarious and new techniques are needed. A piezoelectric transducer element in a feedback system is set to vibrate with its resonance frequency. When the sensor element contacts an object a change in the resonance frequency is observed, and this feature has been utilized in sensor systems to describe physical properties of different objects. For medical applications it has been used to measure stiffness variations due to various patho-physiological conditions. In this study the sensor's ability to measure the stiffness of prostate tissue, from two excised prostatectomy specimens in vitro, was analysed. The specimens were also subjected to morphometric measurements, and the sensor parameter was compared with the morphology of the tissue with linear regression. In the probe impression interval 0.5-1.7 mm, the maximum R(2) > or = 0.60 (p < 0.05, n = 75). An increase in the proportion of prostate stones (corpora amylacea), stroma, or cancer in relation to healthy glandular tissue increased the measured stiffness. Cancer and stroma had the greatest effect on the measured stiffness. The deeper the sensor was pressed, the greater, i.e., deeper, volume it sensed. Tissue sections deeper in the tissue were assigned a lower mathematical weighting than sections closer to the sensor probe. It is concluded that cancer increases the measured stiffness as compared with healthy glandular tissue, but areas with predominantly stroma or many stones could be more difficult to differ from cancer.
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Affiliation(s)
- Ville Jalkanen
- Department of Applied Physics and Electronics, Umeå University, SE-90187 Umeå, Sweden.
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Jalkanen V, Andersson BM, Bergh A, Ljungberg B, Lindahl OA. Prostate tissue stiffness as measured with a resonance sensor system: a study on silicone and human prostate tissue in vitro. Med Biol Eng Comput 2006; 44:593-603. [PMID: 16937195 DOI: 10.1007/s11517-006-0069-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2006] [Accepted: 05/05/2006] [Indexed: 12/01/2022]
Abstract
Prostate cancer is the most common form of cancer in men in Europe and in the USA. Some prostate tumours are stiffer than the surrounding normal tissue, and it could therefore be of interest to measure prostate tissue stiffness. Resonance sensor technology based on piezoelectric resonance detects variations in tissue stiffness due to a change in the resonance frequency. An impression-controlled resonance sensor system was used to detect stiffness in silicone rubber and in human prostate tissue in vitro using two parameters, both combinations of frequency change and force. Variations in silicone rubber stiffness due to the mixing ratio of the two components could be detected (p<0.05) using both parameters. Measurements on prostate tissue showed that there existed a statistically significant (MANOVA test, p<0.001) reproducible difference between tumour tissue (n=13) and normal healthy tissue (n=98) when studying a multivariate parameter set. Both the tumour tissue and normal tissue groups had variations within them, which were assumed to be related to differences in tissue composition. Other sources of error could be uneven surfaces and different levels of dehydration for the prostates. Our results indicated that the resonance sensor could be used to detect stiffness variations in silicone and in human prostate tissue in vitro. This is promising for the development of a future diagnostic tool for prostate cancer.
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Affiliation(s)
- Ville Jalkanen
- Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
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Ramstedt M, Andersson BM, Shchukarev A, Sjöberg S. Surface properties of hydrous manganite (gamma-MnOOH). A potentiometric, electroacoustic, and X-ray photoelectron spectroscopy study. Langmuir 2004; 20:8224-8229. [PMID: 15350096 DOI: 10.1021/la0496338] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The acid-base characteristics of the manganite (gamma-MnOOH) surface have been studied at pH above 6, where dissolution is negligible. Synthetic microcrystalline particles of manganite were used in the experiments. From potentiometric titrations, electrophoretic mobility measurements, and X-ray photoelectron spectroscopy (XPS), a one pK(a) model was constructed that describes the observed behavior. The data show no ionic strength effect at pH < 8.2, which is the pH at the isoelectric point (pH(iep)), but ionic strength effects were visible above this pH. To explain these observations, Na(+) ions were suggested to form a surface complex. The following equilibria were established: =MnOH(2)(+1/2) right harpoon over left harpoon =MnOH(-)(1/2) + H(+), log beta(0) (intr.) = -8.20; =MnOH(2)(+1/2) + Na(+) right harpoon over left harpoon =MnOHNa(+1/2) + H(+), log beta(0) (intr.) = -9.64. The excess of Na(+) at the surface was supported by XPS measurements of manganite suspensions containing 10 mM NaCl. The dielectric constant of synthetic manganite powder was also determined in this study.
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Affiliation(s)
- Madeleine Ramstedt
- Department of Chemistry, Inorganic Chemistry, Umeå University, SE-901 87 Umeå, Sweden.
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Eklund A, Lindén C, Bäcklund T, Andersson BM, Lindahl OA. Evaluation of applanation resonator sensors for intra-ocular pressure measurement: results from clinical and in vitro studies. Med Biol Eng Comput 2003; 41:190-7. [PMID: 12691439 DOI: 10.1007/bf02344887] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Glaucoma is an eye disease that, in its most common form, is characterised by high intra-ocular pressure (IOP), reduced visual field and optic nerve damage. For diagnostic purposes and for follow-up after treatment, it is important to have simple and reliable methods for measuring IOP. Recently, an applanation resonator sensor (ARS) for measuring IOP was introduced and evaluated using an in vitro pig-eye model. In the present study, the first clinical evaluation of the same probe has been carried out, with experiments in vivo on human eyes. There was a low but significant correlation between IOP(ARS) and the IOP measured with a Goldmann applanation tonometer (r = 0.40, p = 0.001, n = 72). However, off-centre positioning of the sensor against the cornea caused a non-negligible source of error. The sensor probe was redesigned to have a spherical, instead of flat, contact surface against the eye and was evaluated in the in vitro model. The new probe showed reduced sensitivity to off-centre positioning, with a decrease in relative deviation from 89% to 11% (1 mm radius). For normalised data, linear regression between IOP(ARS) and direct IOP measurement in the vitreous chamber showed a correlation of r = 0.97 (p < 0.001, n = 108) and a standard deviation for the residuals of SD < or = 2.18 mm Hg (n = 108). It was concluded that a spherical contact surface should be preferred and that further development towards a clinical instrument should focus on probe design and signal analysis.
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Affiliation(s)
- A Eklund
- Department of Biomedical Engineering & Informatics, University Hospital of Umeå, Umeå, Sweden.
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Messner K, Fahlgren A, Persliden J, Andersson BM. Radiographic joint space narrowing and histologic changes in a rabbit meniscectomy model of early knee osteoarthrosis. Am J Sports Med 2001; 29:151-60. [PMID: 11292039 DOI: 10.1177/03635465010290020701] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The purpose of this study was to compare weightbearing radiographs with histologic cartilage evaluation in a rabbit meniscectomy model of the early stage of osteoarthrosis. Fifteen rabbits had a medial meniscectomy performed in one knee and a sham operation in the other knee. Five rabbits each were sacrificed at 13, 25, and 40 weeks after surgery. Radiographic joint space width and histologic cartilage changes of the medial knee compartment were quantified. Five non-operated knees and five knees in which the meniscus had been removed immediately before the evaluations served as control specimens. Overall, the joint space of the peripheral part of the medial knee compartment was narrower in knees operated on for meniscus removal than in sham-operated knees (P < 0.003). In the knees with the meniscus removed, more cartilage changes were seen at the joint surface area of contact on radiographs than in the sham-operated knees (P < 0.0015). Indeed, the area of contact had cartilage changes similar to those in the whole medial compartment. However, there was no correlation between the degree of histologic cartilage change and the corresponding joint space measurements. Joint space width as measured on weightbearing radiographs is reduced after meniscectomy in the rabbit, but it does not reflect the degree of cartilage damage of the loaded joint surfaces in early stages of osteoarthrosis.
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Affiliation(s)
- K Messner
- Department of Neuroscience and Locomotion, Faculty of Health Sciences, Linköping University, Sweden
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Andersson BM, Sundqvist B, Niska J, Loberg B. Thermal conductivity of polycrystalline YBa2Cu4O8. Phys Rev B Condens Matter 1994; 49:4189-4198. [PMID: 10011317 DOI: 10.1103/physrevb.49.4189] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Kelly KB, Bergh C, Andersson BM, Holmberg L. [Do teenagers need play therapy? Great need of teenage-oriented hospital care]. Lakartidningen 1993; 90:4446-9. [PMID: 8271888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- K B Kelly
- Samtliga vid Ostra sjukhuset, Göteborg
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Andersson BM. [Incorrect about fat in meat]. Lakartidningen 1993; 90:3845. [PMID: 8231538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Andersson BM, Sundqvist B. Thermal conductivity of YBa2Cu4O8 dominated by phonon-phonon interactions. Phys Rev B Condens Matter 1993; 48:3575-3578. [PMID: 10008800 DOI: 10.1103/physrevb.48.3575] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Kaminski JJ, Wallmark B, Briving C, Andersson BM. Antiulcer agents. 5. Inhibition of gastric H+/K(+)-ATPase by substituted imidazo[1,2-a]pyridines and related analogues and its implication in modeling the high affinity potassium ion binding site of the gastric proton pump enzyme. J Med Chem 1991; 34:533-41. [PMID: 1847427 DOI: 10.1021/jm00106a008] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A number of substituted imidazo[1,2-a]pyridines and related analogues were selected for biochemical characterization in vitro against both the purified gastric proton pump enzyme, H+/K(+)-ATPase, and the intact gastric gland. The inhibitory activity in these two in vitro models was then examined for correlation with the gastric antisecretory potency determined for these compounds in vivo by using the histamine-stimulated Heidenhain pouch dog. Analysis of the biological data suggested that the inhibitory activity of the analogues determined in two in vitro models is predictive of their in vivo gastric antisecretory activity following intravenous, but not oral, administration. Furthermore, the good correlation observed between the in vitro and in vivo models suggests that these compounds are gastric proton pump inhibitors in vivo. A molecular modeling study of these compounds using the active analogue approach has defined the molecular volume which is shared by the active analogues, as well as the molecular volume which is common to the inactive analogues. Graphical representation of the difference between these molecular volumes can be interpreted in terms of a hypothetical description of the pharmacophore by means of which 3-(cyanomethyl)-2-methyl-8-(phenylmethoxy)imidazo[1,2-a]pyridine, Sch 28080 (1) and its analogues interact with the gastric proton pump enzyme, H+/K(+)-ATPase.
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Affiliation(s)
- J J Kaminski
- Department of Chemical Research, Schering-Plough Research, Schering-Plough Corporation, Bloomfield, New Jersey 07003
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Abstract
A hydrophobic imidazopyridine, SCH 28080 (3-cyanomethyl-2-methyl-8-phenylmethoxy)imidazo[1,2-a]pyridine) has previously been shown to inhibit gastric acid secretion in vivo and in vitro. Studies of isolated gastric H+/K+-ATPase have demonstrated that SCH 28080 reversibly inhibited the enzyme and competitively interacted with the K+-stimulated ATPase and p-nitrophenylphosphatase activities of the H+/K+-ATPase. To elucidate the mechanism of inhibition further, for example to establish whether the inhibitor interaction occurs on the luminal or the cytosolic side of the enzyme or if compound pKa influences inhibition, SCH 28080 and three analogues have been studied. We have examined the effects on K+-stimulated ATPase activity in isolated ion-permeable membrane vesicles at different pH values and KCl concentrations. In ion-tight membrane fractions the effect on acid formation was estimated. The results are in agreement with the hypothesis that the protonated, and thus positively charged, form of SCH 28080 is the active species, and that the inhibitory effect is exerted by binding of the compound to the luminal side of the H+/K+-ATPase.
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Affiliation(s)
- C Briving
- Hässle Gastrointestinal Research Laboratories, Department of Biology, Mölndal, Sweden
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Abstract
AbstractSterile irrigation solutions, used in open systems in a conventional orthopedic operating theatre, were examined for bacterial contamination. At the end of 13 of 21 operations (duration ≥ one hour) the solution tested displayed the growth of Staphylococcus epidermidis and/or diphtheroid rods and/or other species. It is concluded that irrigation by solutions, kept in open bowls during an operation, is a potential source of contamination.
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