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Emran S, Jokinen N, Laitinen K, Lappalainen R, Myllymaa S. Novel 3D printed probe for bioimpedance spectroscopic measurement of oral mucosa: design and testing with ex vivo porcine oral tissues. MEASUREMENT SCIENCE AND TECHNOLOGY 2023; 34:095704. [DOI: 10.1088/1361-6501/acd658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Abstract
Three-dimensional (3D) printing has a high potential in various biomedical applications. We hypothesize that 3D printing could be a viable option to construct novel bioimpedance spectroscopic (BIS) sensors suitable for electrochemical characterization of oral mucosal tissues. Previous BIS studies have relied on hand-made probes possessing significant limitations related to their single patient disposable use, large inter-probe differences, and weak reproducibility of measurement. There is also uncertainty related to the effect of varying loading pressure between the probe and biological tissue. Here, we introduce three differently sized rectangular shaped 3D printed probes and test those using a four-terminal measurement principle on various porcine oral tissue samples. We find that constructing a fully 3D printed probe is a challenging task, prone to issues relating to short-circuiting or electrochemical corrosion. However, our final prototype version, constructed with silver-coated copper electrodes, showed favorable characteristics in BIS experiments. All three differently sized probes were able to differentiate between different tissue types with excellent reproducibility. The effect of loading pressure was found to be almost negligible when using small- and medium-sized probes. However, further studies are needed to measure tissues with uneven surfaces, such as palatinum, and to avoid manual or (electro)chemical surface-finishing steps.
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Guo J, He M, Li Z, Cai S, Xiong X, Cheng Z. Piezoresistivity modeling of soft tissue electrical-mechanical properties: A validation study. Proc Inst Mech Eng H 2023; 237:936-945. [PMID: 37387354 DOI: 10.1177/09544119231183545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
In general, the electrical property of soft tissues is sensitive to the force applied to their surface. To further study the relationship between the force and the electrical property of soft tissues, this paper attempts to investigate the effect of static and higher-order stresses on electrical properties. Overall, a practical experimental platform is designed to acquire the force information and the electrical property of soft tissues during a contact procedure, which is featured different compression stimuli, such as constant pressing force, constant pressing speed, and step-force compression, etc. Furthermore, the piezoresistive characteristic is innovatively introduced to model the mechanical-electrical properties of soft tissue. Finite Element Modeling (FEM) is adopted to fit the static piezoresistivity of the soft tissue. Finally, experimental studies were performed to demonstrate the effect of stress on the electrical properties and the feasibility of the proposed piezoresistive model to describe soft tissues' mechanical and electrical properties.
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Affiliation(s)
- Jing Guo
- School of Automation, Guangdong University of Technology, Guangzhou, Guangdong, China
| | - Min He
- School of Automation, Guangdong University of Technology, Guangzhou, Guangdong, China
| | - Zhichao Li
- Key Laboratory of Land Surface Pattern and Simulation, Institute of Geo-graphic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
| | - Shuting Cai
- School of Integrated Circuits, Guangdong University of Technology, Guangzhou, Guangdong, China
| | - Xiaoming Xiong
- School of Integrated Circuits, Guangdong University of Technology, Guangzhou, Guangdong, China
| | - Zhuoqi Cheng
- Maersk Mc Kinney Moller Institute, University of Southern Denmark, Odense, Denmark
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Maldonado-Valadez RE, Falcón-Sandoval EB, Vargas-Luna FM, Kashina S, Balleza-Ordaz JM. Detrusor pressure monitoring by electrical bioimpedance in the neurogenic bladder of adult patients. Int Urol Nephrol 2022; 54:3107-3115. [PMID: 36001269 DOI: 10.1007/s11255-022-03342-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/14/2022] [Indexed: 11/28/2022]
Abstract
PURPOSE Detrusor pressure-volume relationship evaluation by urodynamics provides useful clinical information; however, it is invasive, and requires specific installations. An alternative technique proposed by our research group is the electrical bioimpedance (BI) which is an easily performed and non-invasive method. In this work, we assess the relationship between BI and detrusor bladder pressure in adults with neurogenic lower urinary tract dysfunction. METHODS A prospective observational study was conducted. 20 patients (11 females and 9 male) previously diagnosed with neurogenic bladder were included. All participants underwent simultaneously a urodynamic evaluation (UDS) and BI determination, and both examination signals were recorded and subjected to Shapiro-Wilks statistical test. A correlational statistical test was used to compare the pressure parameters (detrusor, vesical and abdominal) with their respective BI determinations. Subsequently, a linear regression test was performed to evaluate the concordance between BI and their respective pressure values. RESULTS From the 20 correlations, between detrusor bladder pressure (PDET) and abdominal bioimpedance determinations (ZABD), obtained for all participants, 16 evidenced significant results over 90% (p < 0.05). CONCLUSIONS A significantly high correlation between abdominal bioimpedance determinations and the detrusor bladder pressures was evidenced. These results should be confirmed in a larger group of participants.
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Affiliation(s)
- Rafael Edgardo Maldonado-Valadez
- Urology Department, Hospital Regional de Alta Especialidad del Bajío (HRAEB), San Carlos la Roncha, 37660, León, Guanajuato, México
| | - Erika Beatriz Falcón-Sandoval
- Urology Department, Hospital Regional de Alta Especialidad del Bajío (HRAEB), San Carlos la Roncha, 37660, León, Guanajuato, México.,Department of Medical Physics, University of Guanajuato, Lomas del Bosque #103, Lomas del Campestre, 37150, León, Guanajuato, México
| | - Francisco Miguel Vargas-Luna
- Department of Medical Physics, University of Guanajuato, Lomas del Bosque #103, Lomas del Campestre, 37150, León, Guanajuato, México
| | - Svetlana Kashina
- Department of Medical Physics, University of Guanajuato, Lomas del Bosque #103, Lomas del Campestre, 37150, León, Guanajuato, México
| | - José Marco Balleza-Ordaz
- Department of Medical Physics, University of Guanajuato, Lomas del Bosque #103, Lomas del Campestre, 37150, León, Guanajuato, México.
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Schule J, Kraus F, Veil C, Kunkel S, Somers P, Tarin C, Sawodny O. Multi-Physical Tissue Modeling of a Human Urinary Bladder. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2021; 2021:4297-4302. [PMID: 34892172 DOI: 10.1109/embc46164.2021.9629482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
A multi-physical model of a human urinary bladder is an essential element for the potential application of electrical impedance spectroscopy during transurethral resection surgery, where measurements are taken at different fill levels inside the bladder. This work derives a multi-physical bladder tissue model that incorporates the electrical impedance properties with dependence on mechanical deformation due to filling of the bladder. The volume and ratio of the intracellular to extracellular tissue fluid heavily influence the electrical impedance characteristics and thus provide the connection between the mechanical and electrical domains. Modeling the fluid within the tissue links both the physical and histological processes and enables useful inferences of the properties from empiric observations. This is demonstrated by taking impedance measurements at different fill volumes. The resulting model provides a tool to analyze impedance measurements during surgery at different stress levels. In addition, this model can be used to determine patient-specific tissue parameters.
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Effect of Open-Ended Coaxial Probe-to-Tissue Contact Pressure on Dielectric Measurements. SENSORS 2020; 20:s20072060. [PMID: 32268598 PMCID: PMC7181017 DOI: 10.3390/s20072060] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/01/2020] [Accepted: 04/03/2020] [Indexed: 12/21/2022]
Abstract
Open-ended coaxial probes are widely used to gather dielectric properties of biological tissues. Due to the lack of an agreed data acquisition protocol, several environmental conditions can cause inaccuracies when comparing dielectric data. In this work, the effect of a different measurement probe-to-tissue contact pressure was monitored in the frequency range from 0.5 to 20 GHz. Therefore, we constructed a controlled lifting platform with an integrated pressure sensor to exert a constant pressure on the tissue sample during the dielectric measurement. In the pressure range from 7.74 kPa to 77.4 kPa, we observed a linear correlation of - 0 . 31 ± 0 . 09 % and - 0 . 32 ± 0 . 14 % per kPa for, respectively, the relative real and imaginary complex permittivity. These values are statistically significant compared with the reported measurement uncertainty. Following the literature in different biology-related disciplines regarding pressure-induced variability in measurements, we hypothesize that these changes originate from squeezing out the interstitial and extracellular fluid. This process locally increases the concentration of membranes, cellular organelles, and proteins in the sensed volume. Finally, we suggest moving towards a standardized probe-to-tissue contact pressure, since the literature has already demonstrated that reprobing at the same pressure can produce repeatable data within a 1% uncertainty interval.
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Yang CH, Li W, Chen RK. Determination of Tissue Thermal Conductivity as a Function of Thermal Dose and Its Application in Finite Element Modeling of Electrosurgical Vessel Sealing. IEEE Trans Biomed Eng 2020; 67:2862-2869. [PMID: 32054566 DOI: 10.1109/tbme.2020.2972465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Electrosurgical vessel sealing is a process commonly used to control bleeding during surgical procedures. Finite element (FE) modeling is often performed to obtain a better understanding of thermal spread during this process. The accuracy of the FE model depends on the implemented material properties. Thermal conductivity is one of the most important properties that affect temperature distribution. The goal of this study is to determine the tissue thermal conductivity as a function of thermal dose. Methods: We developed an iterative approach to correlating tissue thermal conductivity to more accurately calculated thermal dose, which cannot be experimentally measured. The resulting regression model was then implemented into an electrosurgical vessel sealing FE model to examine the accuracy of this FE model. Results: The results show that with the regression model, more reasonable temperature and thermal dose prediction can be achieved at the center of the sealed vessel tissue. The resulting electrical current and impedance from the FE model match with the experimental results. Conclusion: The developed approach can be used to determine the correlation between thermal dose and thermal conductivity. Describing the thermal conductivity as a function of thermal dose allows modeling of irreversible changes in tissue properties. Significance: By having a more accurate temperature estimation at the center of the sealed vessel, more insight is provided into how the tissue reacts during the vessel sealing process.
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Concentric Ring Probe for Bioimpedance Spectroscopic Measurements: Design and Ex Vivo Feasibility Testing on Pork Oral Tissues. SENSORS 2018; 18:s18103378. [PMID: 30308986 PMCID: PMC6210762 DOI: 10.3390/s18103378] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 09/19/2018] [Accepted: 10/03/2018] [Indexed: 11/17/2022]
Abstract
Many oral diseases, such as oral leukoplakia and erythroplakia, which have a high potential for malignant transformations, cause abnormal structural changes in the oral mucosa. These changes are clinically assessed by visual inspection and palpation despite their poor accuracy and subjective nature. We hypothesized that non-invasive bioimpedance spectroscopy (BIS) might be a viable option to improve the diagnostics of potentially malignant lesions. In this study, we aimed to design and optimize the measurement setup and to conduct feasibility testing on pork oral tissues. The contact pressure between a custom-made concentric ring probe and tissue was experimentally optimized. The effects of loading time and inter-electrode spacing on BIS spectra were also clarified. Tissue differentiation testing was performed for ex vivo pork oral tissues including palatinum, buccal mucosa, fat, and muscle tissue samples. We observed that the most reproducible results were obtained by using a loading weight of 200 g and a fixed time period under press, which was necessary to allow meaningful quantitative comparison. All studied tissues showed their own unique spectra, accompanied by significant differences in both impedance magnitude and phase (p ≤ 0.014, Kruskal-Wallis test). BIS shows promise, and further studies are warranted to clarify its potential to detect specific pathological tissue alterations.
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Ruiz-Vargas A, Ivorra A, Arkwright JW. Design, Construction and Validation of an Electrical Impedance Probe with Contact Force and Temperature Sensors Suitable for in-vivo Measurements. Sci Rep 2018; 8:14818. [PMID: 30287842 PMCID: PMC6172255 DOI: 10.1038/s41598-018-33221-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 09/19/2018] [Indexed: 12/31/2022] Open
Abstract
Bioimpedance spectroscopy measurements can be used for tissue characterization. These measurements can be performed in soft tissues by direct contact of a non-invasive probe consisting of two or four electrodes. The amount of force applied by users can be quite different, and the measurements can vary as a result. To compensate for this, we have built an electrical impedance probe (diameter 3.2 mm) with fibre optic contact-force and temperature sensors built in it. The different sensors of the probe were tested individually. The errors in magnitude and phase angle of the probe are <0.9% and <4°, respectively, for a 0.9% NaCl solution. The linear dynamic range of the force sensor was from 0 to 100 grams. An ex-vivo experiment on a section of proximal colon from a guinea-pig was performed. Twenty bioimpedance measurements were taken in a frequency range of 5 kHz to 1 MHz, while simultaneously recording the force applied. For an increase in contact pressure applied to tissue from 0 to 15.4 kPa, the maximum change in resistivity was 33% at 5 kHz and the minimum was 6.6% at 142 kHz. The probe is small enough to be introduced via the instrument port of an endoscope.
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Affiliation(s)
- Albert Ruiz-Vargas
- The Medical Device Research Institute, College of Science and Engineering, Flinders University, Adelaide, Australia.
| | - Antoni Ivorra
- Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
- Serra Húnter Programme, Universitat Pompeu Fabra, Barcelona, Spain
| | - John William Arkwright
- The Medical Device Research Institute, College of Science and Engineering, Flinders University, Adelaide, Australia
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Knabe M, Kurz C, Knoll T, Velten T, Vieth M, Manner H, Ell C, Pech O. Diagnosing early Barrett's neoplasia and oesophageal squamous cell neoplasia by bioimpedance spectroscopy in human tissue. United European Gastroenterol J 2014; 1:236-41. [PMID: 24917967 DOI: 10.1177/2050640613495198] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 05/26/2013] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Detection of early oesophageal cancer in surrounding normal tissue can be challenging, but detection is essential to determine the subsequent treatment. Dysplastic tissue can be detected by using electrical impedance spectroscopy (EIS). OBJECTIVE The aim of the present study was to evaluate the feasibility and value of EIS in the diagnosis of oesophageal neoplasia. METHODS This prospective ex-vivo study included 23 patients with early oesophageal cancer (17 with Barrett's cancer and six with early squamous cell cancer). Immediately after endoscopic resection, the electrical properties of the resected specimens were investigated using a pencil probe (5 mm in diameter, frequency range from 100 Hz to 1 MHz). Punch biopsies were taken from the measured site in order to compare the results of EIS with histology. RESULTS EIS was able to detect dysplastic oesophageal mucosa with a high rate of accuracy (82% in Barrett's oesophagus and 100% in squamous oesophagus) A total of 54 different sites in 26 tumours were evaluated. CONCLUSIONS EIS was able to differentiate reliably between non-neoplastic and neoplastic oesophageal mucosa. Using EIS, it might be possible to use it for targeted biopsies and to avoid unnecessary biopsies during cancer surveillance in future.
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Affiliation(s)
- Mate Knabe
- HSK Wiesbaden (Teaching Hospital of the University of Mainz), Wiesbaden, Germany
| | - Christian Kurz
- Fraunhofer Institute for Biomedical Engineering IBMT, St. Ingbert, Germany
| | - Thorsten Knoll
- Fraunhofer Institute for Biomedical Engineering IBMT, St. Ingbert, Germany
| | - Thomas Velten
- Fraunhofer Institute for Biomedical Engineering IBMT, St. Ingbert, Germany
| | | | - Hendrik Manner
- HSK Wiesbaden (Teaching Hospital of the University of Mainz), Wiesbaden, Germany
| | - Christian Ell
- HSK Wiesbaden (Teaching Hospital of the University of Mainz), Wiesbaden, Germany
| | - Oliver Pech
- HSK Wiesbaden (Teaching Hospital of the University of Mainz), Wiesbaden, Germany ; St John of God Hospital, Regensburg, Germany
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Bladder cancer detection using electrical impedance technique (tabriz mark 1). PATHOLOGY RESEARCH INTERNATIONAL 2012; 2012:470101. [PMID: 22567538 PMCID: PMC3337498 DOI: 10.1155/2012/470101] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 01/16/2012] [Accepted: 02/14/2012] [Indexed: 11/17/2022]
Abstract
Bladder cancer is the fourth most common malignant neoplasm in men and the eighth in women. Bladder pathology is usually investigated visually by cystoscopy. In this technique, biopsies are obtained from the suspected area and then, after needed procedure, the diagnostic information can be taken. This is a relatively difficult procedure and is associated with discomfort for the patient and morbidity. Therefore, the electrical impedance spectroscopy (EIS), a minimally invasive screening technique, can be used to separate malignant areas from nonmalignant areas in the urinary bladder. The feasibility of adapting this technique to screen for bladder cancer and abnormalities during cystoscopy has been explored and compared with histopathological evaluation of urinary bladder lesions. Ex vivo studies were carried out in this study by using a total of 30 measured points from malignant and 100 measured points from non-malignant areas of patients bladders in terms of their biopsy reports matching to the electrical impedance measurements. In all measurements, the impedivity of malignant area of bladder tissue was significantly higher than the impedivity of non-malignant area this tissue (P < 0.005).
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Keshtkar A, Salehnia Z, Somi MH, Eftekharsadat AT. Some early results related to electrical impedance of normal and abnormal gastric tissue. Phys Med 2011; 28:19-24. [PMID: 21334938 DOI: 10.1016/j.ejmp.2011.01.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2010] [Revised: 12/22/2010] [Accepted: 01/23/2011] [Indexed: 10/18/2022] Open
Abstract
Gastric cancer is the fourth most common cancer and most patients with gastric cancer are being diagnosed in advanced stages of the disease so they do not gain any survival chance from conventional surgical, chemotherapeutic or radiotherapeutic methods. These are relatively high cost procedures in terms of both time and money. This study considers the introduction of a novel minimally invasive diagnostic technique which shows the relationship between histopathology and the electrical impedance spectrum in the human stomach. In this study, 4 electrode technique was used to differentiate tissues from each other using Tabriz Mark 1 electrical impedance system (30 different frequencies in the range of 2 kHz to 1 MHz). A total of 97 points from 45 patients were studied in terms of their biopsy reports matching to the electrical impedance measurements (in vivo). After impedance measurements and applying calibration factors, a non-parametric statistical technique, the Kruskal-Wallis test was used to evaluate the difference among the groups. According to the calculation of respective data using this spectroscopy system, the resistivity of the normal group was higher than that of the benign group, and the resistivity of these groups were higher than that of the malignant group at frequencies between 470 kHz and 1 MHz (P < 0.05). In these frequencies, the impedivity of the dysplastic tissue was significantly lower than that of the other groups (P < 0.05). Also, Cole equation fitting procedure was used to generate a scatter plot of the malignant and benign points: it shows in general, benign points had higher values of R than the malignant points. Therefore, electrical impedance spectroscopy can be a useful technique to characterize the stomach tissue.
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Affiliation(s)
- A Keshtkar
- Medical Physics Department, Medical Faculty, Tabriz University of Medical Sciences, Tabriz, Iran.
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Leonhardt S, Cordes A, Plewa H, Pikkemaat R, Soljanik I, Moehring K, Gerner HJ, Rupp R. Electric impedance tomography for monitoring volume and size of the urinary bladder. ACTA ACUST UNITED AC 2011; 56:301-7. [DOI: 10.1515/bmt.2011.022] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Keshtkar A, Mesbahi A, Rasta S, Keshtkar A. The feasibility of computational modelling technique to detect the bladder cancer. Phys Med 2010; 26:34-7. [DOI: 10.1016/j.ejmp.2009.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2008] [Revised: 05/31/2009] [Accepted: 06/17/2009] [Indexed: 01/04/2023] Open
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