The Experts below are selected from a list of 39 Experts worldwide ranked by ideXlab platform
Maurice C G Aalders - One of the best experts on this subject based on the ideXlab platform.
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Hyperspectral imaging for the age estimation of blood stains at the crime scene.
Forensic science international, 2012Co-Authors: Gerda Edelman, Ton G Van Leeuwen, Maurice C G AaldersAbstract:The age estimation of blood stains can provide important information on the temporal aspects of a crime. As previously shown, visible spectroscopy of blood stains can successfully be used for their age estimation. In the present study we evaluated the feasibility to use hyperspectral imaging for this purpose. Visible reflectance spectra of blood stains were recorded using a pushbroom hyperspectral imaging system. From these spectra, the relative amounts of oxyHemoglobin, metHemoglobin and hemichrome within the blood stains were derived. By comparison of the Hemoglobin Derivative fractions with a reference dataset, the age of blood stains up to 200 days old was estimated. The absolute error of the age estimation task increased with age, with a median relative error of 13.4% of the actual age. To test the practical applicability of this method, a simulated crime scene was analyzed, in which blood stains of several ages were deposited. Hyperspectral imaging combined with the proposed analysis provided insight in the absolute age of the blood stains. Additionally, the blood stains were clustered based on their Hemoglobin Derivative fractions, without the use of a reference dataset. Results demonstrated that the order of formation of blood stains can be determined, even under unknown environmental circumstances, when no proficient reference dataset is available. These findings are an important step toward the practical implementation of blood stain age estimation in forensic casework.
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Age estimation of blood stains by Hemoglobin Derivative determination using reflectance spectroscopy.
Forensic science international, 2010Co-Authors: Rolf H Bremmer, Annemarie Nadort, Ton G Van Leeuwen, Martin J C Van Gemert, Maurice C G AaldersAbstract:Blood stains can be crucial in reconstructing crime events. However, no reliable methods are currently available to establish the age of a blood stain on the crime scene. We show that determining the fractions of three Hemoglobin Derivatives in a blood stain at various ages enables relating these time varying fractions to the age of the blood stain. Application of light transport theory allows addressing the spectroscopic changes in ageing blood stains to changes in chemical composition, i.e. the transition of oxy-Hemoglobin into met-Hemoglobin and hemichrome. We have found in 20 blood stains that the chemical composition of the blood stain with age, called Hemoglobin reaction kinetics, under controlled circumstances, shows a distinct time-dependent behavior, with a unique combination of the three Hemoglobin Derivatives at all moments in time. Finally, we employed the Hemoglobin reaction kinetics inversely to assess the age of 20 other blood stains studied, again over a time period of 0-60 days. We estimated an age of e.g. 55 days correct within an uncertainty margin of 14 days. In conclusion, we propose that the results obtained under controlled conditions demand further evaluation of their possible value for age determination of blood stains on crime scenes.
Hanli Liu - One of the best experts on this subject based on the ideXlab platform.
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Steady-State Reflectance Spectroscopy Used to Quantify Hemodynamic and Optical Properties of Tissue: Demonstration of Heterogeneities of Human Prostrates
Biomedical Optics, 2008Co-Authors: Dheerendra Kashyap, Disha Peswani, Jeffrey A. Cadeddu, Hanli LiuAbstract:Heterogeneities in Hemoglobin Derivative concentrations and light scattering properties taken from ex vivo human prostate glands are demonstrated by using steady-state, single source-detector separation (1-3 cm) reflectance spectroscopy.
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Absolute Quantification of Hemoglobin Derivative Concentrations and Reduced Scattering Coefficients from Turbid Media using Steady State Reflectance Spectroscopy with Single Source-Detector Separation
Biomedical Optics, 2006Co-Authors: Dheerendra Kashyap, Hanli LiuAbstract:Steady state broadband (650-845nm) reflectance spectroscopy yields absolute concentrations of Hemoglobin Derivatives and reduced scattering coefficients of blood-intralipid phantoms within 15% relative error, using an algorithm developed from diffusion approximation.
Dheerendra Kashyap - One of the best experts on this subject based on the ideXlab platform.
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Steady-State Reflectance Spectroscopy Used to Quantify Hemodynamic and Optical Properties of Tissue: Demonstration of Heterogeneities of Human Prostrates
Biomedical Optics, 2008Co-Authors: Dheerendra Kashyap, Disha Peswani, Jeffrey A. Cadeddu, Hanli LiuAbstract:Heterogeneities in Hemoglobin Derivative concentrations and light scattering properties taken from ex vivo human prostate glands are demonstrated by using steady-state, single source-detector separation (1-3 cm) reflectance spectroscopy.
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Absolute Quantification of Hemoglobin Derivative Concentrations and Reduced Scattering Coefficients from Turbid Media using Steady State Reflectance Spectroscopy with Single Source-Detector Separation
Biomedical Optics, 2006Co-Authors: Dheerendra Kashyap, Hanli LiuAbstract:Steady state broadband (650-845nm) reflectance spectroscopy yields absolute concentrations of Hemoglobin Derivatives and reduced scattering coefficients of blood-intralipid phantoms within 15% relative error, using an algorithm developed from diffusion approximation.
Ton G Van Leeuwen - One of the best experts on this subject based on the ideXlab platform.
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Hyperspectral imaging for the age estimation of blood stains at the crime scene.
Forensic science international, 2012Co-Authors: Gerda Edelman, Ton G Van Leeuwen, Maurice C G AaldersAbstract:The age estimation of blood stains can provide important information on the temporal aspects of a crime. As previously shown, visible spectroscopy of blood stains can successfully be used for their age estimation. In the present study we evaluated the feasibility to use hyperspectral imaging for this purpose. Visible reflectance spectra of blood stains were recorded using a pushbroom hyperspectral imaging system. From these spectra, the relative amounts of oxyHemoglobin, metHemoglobin and hemichrome within the blood stains were derived. By comparison of the Hemoglobin Derivative fractions with a reference dataset, the age of blood stains up to 200 days old was estimated. The absolute error of the age estimation task increased with age, with a median relative error of 13.4% of the actual age. To test the practical applicability of this method, a simulated crime scene was analyzed, in which blood stains of several ages were deposited. Hyperspectral imaging combined with the proposed analysis provided insight in the absolute age of the blood stains. Additionally, the blood stains were clustered based on their Hemoglobin Derivative fractions, without the use of a reference dataset. Results demonstrated that the order of formation of blood stains can be determined, even under unknown environmental circumstances, when no proficient reference dataset is available. These findings are an important step toward the practical implementation of blood stain age estimation in forensic casework.
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Age estimation of blood stains by Hemoglobin Derivative determination using reflectance spectroscopy.
Forensic science international, 2010Co-Authors: Rolf H Bremmer, Annemarie Nadort, Ton G Van Leeuwen, Martin J C Van Gemert, Maurice C G AaldersAbstract:Blood stains can be crucial in reconstructing crime events. However, no reliable methods are currently available to establish the age of a blood stain on the crime scene. We show that determining the fractions of three Hemoglobin Derivatives in a blood stain at various ages enables relating these time varying fractions to the age of the blood stain. Application of light transport theory allows addressing the spectroscopic changes in ageing blood stains to changes in chemical composition, i.e. the transition of oxy-Hemoglobin into met-Hemoglobin and hemichrome. We have found in 20 blood stains that the chemical composition of the blood stain with age, called Hemoglobin reaction kinetics, under controlled circumstances, shows a distinct time-dependent behavior, with a unique combination of the three Hemoglobin Derivatives at all moments in time. Finally, we employed the Hemoglobin reaction kinetics inversely to assess the age of 20 other blood stains studied, again over a time period of 0-60 days. We estimated an age of e.g. 55 days correct within an uncertainty margin of 14 days. In conclusion, we propose that the results obtained under controlled conditions demand further evaluation of their possible value for age determination of blood stains on crime scenes.
Rolf H Bremmer - One of the best experts on this subject based on the ideXlab platform.
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Age estimation of blood stains by Hemoglobin Derivative determination using reflectance spectroscopy.
Forensic science international, 2010Co-Authors: Rolf H Bremmer, Annemarie Nadort, Ton G Van Leeuwen, Martin J C Van Gemert, Maurice C G AaldersAbstract:Blood stains can be crucial in reconstructing crime events. However, no reliable methods are currently available to establish the age of a blood stain on the crime scene. We show that determining the fractions of three Hemoglobin Derivatives in a blood stain at various ages enables relating these time varying fractions to the age of the blood stain. Application of light transport theory allows addressing the spectroscopic changes in ageing blood stains to changes in chemical composition, i.e. the transition of oxy-Hemoglobin into met-Hemoglobin and hemichrome. We have found in 20 blood stains that the chemical composition of the blood stain with age, called Hemoglobin reaction kinetics, under controlled circumstances, shows a distinct time-dependent behavior, with a unique combination of the three Hemoglobin Derivatives at all moments in time. Finally, we employed the Hemoglobin reaction kinetics inversely to assess the age of 20 other blood stains studied, again over a time period of 0-60 days. We estimated an age of e.g. 55 days correct within an uncertainty margin of 14 days. In conclusion, we propose that the results obtained under controlled conditions demand further evaluation of their possible value for age determination of blood stains on crime scenes.