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Carmen Garciaruiz - One of the best experts on this subject based on the ideXlab platform.
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progressing the analysis of improvised explosive devices comparative study for trace detection of explosive residues in handprints by raman spectroscopy and liquid chromatography
Talanta, 2016Co-Authors: Felix Zapata, Ma Angeles Fernandez De La Ossa, Elizabeth Gilchrist, Leon Barron, Carmen GarciaruizAbstract:Concerning the dreadful global threat of terrorist attacks, the detection of explosive residues in biological traces and marks is a current need in both forensics and homeland security. This study examines the potential of Raman microscopy in comparison to liquid chromatography (ion chromatography (IC) and reversed-phase high performance liquid chromatography (RP-HPLC)) to detect, identify and quantify residues in human handmarks of explosives and energetic salts commonly used to manufacture Improvised Explosive Devices (IEDs) including Dynamite, ammonium nitrate, single- and double-smokeless gunpowders and black powder. Dynamite, ammonium nitrate and black powder were detected through the identification of the energetic salts by Raman spectroscopy, their respective anions by IC, and organic components by RP-HPLC. Smokeless gunpowders were not detected, either by Raman spectroscopy or the two liquid chromatography techniques. Several aspects of handprint collection, sample treatment and a critical comparison of the identification of compounds by both techniques are discussed. Raman microscopy and liquid chromatography were shown to be complementary to one another offering more comprehensive information for trace explosives analysis.
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near infrared spectral imaging for the analysis of Dynamite residues on human handprints
Talanta, 2014Co-Authors: Ma Angeles Fernandez De La Ossa, Carmen Garciaruiz, Jose Manuel AmigoAbstract:This study examines the utility of near infrared hyperspectral imaging (NIR-HSI) combined with chemometrics for the detection of Dynamite residues on human handprints. Polyvinyl sheets containing Dynamite residues were then analysed with the NIR-HSI system. A spectral library was developed by using partial least squares-discriminant analysis model (PLS-DA) to detect and classify the pixels contaminated with the Dynamite residues. Values of sensitivity and specificity of 100% were obtained for both calibration and cross validation of Dynamite and ammonium nitrate. The results were tested in real human handprints. Seven volunteers deposited their handprints into polyvinyl transparent sheets after the manipulation of a common type of Dynamite which was mainly composed by ammonium nitrate. These results highlight the extremely high potential and capability of NIR-HSI combined with chemometrics for the fast and easy identification of explosive residues and additionally, its potential competence to detect the explosive manipulation.
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detection of residues from explosive manipulation by near infrared hyperspectral imaging a promising forensic tool
Forensic Science International, 2014Co-Authors: Ma Angeles Fernandez De La Ossa, Jose Manuel Amigo, Carmen GarciaruizAbstract:In this study near infrared hyperspectral imaging (NIR-HSI) is used to provide a fast, non-contact, non-invasive and non-destructive method for the analysis of explosive residues on human handprints. Volunteers manipulated individually each of these explosives and after deposited their handprints on plastic sheets. For this purpose, classical explosives, potentially used as part of improvised explosive devices (IEDs) as ammonium nitrate, blackpowder, single- and double-base smokeless gunpowders and Dynamite were studied. A partial-least squares discriminant analysis (PLS-DA) model was built to detect and classify the presence of explosive residues in handprints. High levels of sensitivity and specificity for the PLS-DA classification model created to identify ammonium nitrate, blackpowder, single- and double-base smokeless gunpowders and Dynamite residues were obtained, allowing the development of a preliminary library and facilitating the direct and in situ detection of explosives by NIR-HSI. Consequently, this technique is showed as a promising forensic tool for the detection of explosive residues and other related samples.
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Dynamite analysis by raman spectroscopy as a unique analytical tool
Analytical Chemistry, 2013Co-Authors: Maria Lopezlopez, Jose Luis Ferrando, Carmen GarciaruizAbstract:Apart from powerful explosives, Dynamites are complex samples with an intricate analysis. These mixtures of compounds of diverse chemical nature present a challenge to the analyst, and as a result, several analytical techniques need to be applied currently for their analysis. Taking into account that presently there are almost no methods for Dynamite analysis in the literature, it is crucial to develop analytical methods that could be applied for the analysis of these samples. This study introduces the use of Raman spectroscopy to analyze Dynamites. Two different Dynamites made up of ethylene glycol dinitrate and ammonium nitrate, among other minor components, were analyzed by Raman spectroscopy. First, confocal Raman spectroscopy allowed the identification of different components easily distinguished by eye (ammonium nitrate, ethylene glycol dinitrate, and sawdust). Then, Raman mapping was used to show the distribution of the main components throughout the Dynamite mass. Finally, several minor components were identified after flocculation (nitrocellulose) or precipitation (sawdust, CaCO3, and flour). The results obtained demonstrate the huge potential of this technique for the analysis of such a complex and tricky sample.
Ma Angeles Fernandez De La Ossa - One of the best experts on this subject based on the ideXlab platform.
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progressing the analysis of improvised explosive devices comparative study for trace detection of explosive residues in handprints by raman spectroscopy and liquid chromatography
Talanta, 2016Co-Authors: Felix Zapata, Ma Angeles Fernandez De La Ossa, Elizabeth Gilchrist, Leon Barron, Carmen GarciaruizAbstract:Concerning the dreadful global threat of terrorist attacks, the detection of explosive residues in biological traces and marks is a current need in both forensics and homeland security. This study examines the potential of Raman microscopy in comparison to liquid chromatography (ion chromatography (IC) and reversed-phase high performance liquid chromatography (RP-HPLC)) to detect, identify and quantify residues in human handmarks of explosives and energetic salts commonly used to manufacture Improvised Explosive Devices (IEDs) including Dynamite, ammonium nitrate, single- and double-smokeless gunpowders and black powder. Dynamite, ammonium nitrate and black powder were detected through the identification of the energetic salts by Raman spectroscopy, their respective anions by IC, and organic components by RP-HPLC. Smokeless gunpowders were not detected, either by Raman spectroscopy or the two liquid chromatography techniques. Several aspects of handprint collection, sample treatment and a critical comparison of the identification of compounds by both techniques are discussed. Raman microscopy and liquid chromatography were shown to be complementary to one another offering more comprehensive information for trace explosives analysis.
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near infrared spectral imaging for the analysis of Dynamite residues on human handprints
Talanta, 2014Co-Authors: Ma Angeles Fernandez De La Ossa, Carmen Garciaruiz, Jose Manuel AmigoAbstract:This study examines the utility of near infrared hyperspectral imaging (NIR-HSI) combined with chemometrics for the detection of Dynamite residues on human handprints. Polyvinyl sheets containing Dynamite residues were then analysed with the NIR-HSI system. A spectral library was developed by using partial least squares-discriminant analysis model (PLS-DA) to detect and classify the pixels contaminated with the Dynamite residues. Values of sensitivity and specificity of 100% were obtained for both calibration and cross validation of Dynamite and ammonium nitrate. The results were tested in real human handprints. Seven volunteers deposited their handprints into polyvinyl transparent sheets after the manipulation of a common type of Dynamite which was mainly composed by ammonium nitrate. These results highlight the extremely high potential and capability of NIR-HSI combined with chemometrics for the fast and easy identification of explosive residues and additionally, its potential competence to detect the explosive manipulation.
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detection of residues from explosive manipulation by near infrared hyperspectral imaging a promising forensic tool
Forensic Science International, 2014Co-Authors: Ma Angeles Fernandez De La Ossa, Jose Manuel Amigo, Carmen GarciaruizAbstract:In this study near infrared hyperspectral imaging (NIR-HSI) is used to provide a fast, non-contact, non-invasive and non-destructive method for the analysis of explosive residues on human handprints. Volunteers manipulated individually each of these explosives and after deposited their handprints on plastic sheets. For this purpose, classical explosives, potentially used as part of improvised explosive devices (IEDs) as ammonium nitrate, blackpowder, single- and double-base smokeless gunpowders and Dynamite were studied. A partial-least squares discriminant analysis (PLS-DA) model was built to detect and classify the presence of explosive residues in handprints. High levels of sensitivity and specificity for the PLS-DA classification model created to identify ammonium nitrate, blackpowder, single- and double-base smokeless gunpowders and Dynamite residues were obtained, allowing the development of a preliminary library and facilitating the direct and in situ detection of explosives by NIR-HSI. Consequently, this technique is showed as a promising forensic tool for the detection of explosive residues and other related samples.
Christoph Juchem - One of the best experts on this subject based on the ideXlab platform.
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Dynamic multicoil technique (Dynamite) MRI on human brain.
Magnetic resonance in medicine, 2020Co-Authors: Christoph Juchem, Sebastian Theilenberg, Chathura Kumaragamage, Michael Mullen, Lance Delabarre, Gregor Adriany, Peter B. Brown, Scott Mcintyre, Terence W. Nixon, Michael GarwoodAbstract:PURPOSE Spatial encoding for MRI is generally based on linear x, y, and z magnetic field gradients generated by a set of dedicated gradient coils. We recently introduced the dynamic multicoil technique (Dynamite) for B0 field control and demonstrated Dynamite MRI in a preclinical MR environment. In this study, we report the first realization of Dynamite MRI of the in vivo human head. METHODS Gradient fields for Dynamite MRI were generated with a 28-channel multicoil hardware arranged in 4 rows of 7 coils on a cylindrical surface (length 359 mm, diameter 344 mm, maximum 5 A per coil). Dynamite MRIs of a resolution phantom and in vivo human heads were acquired with multislice gradient-echo, multislice spin-echo, and 3D gradient-echo sequences. The resultant image fidelity was compared to that obtained with conventional gradient coil technology. RESULTS Dynamite field control enabled the realization of all imaging sequences with average gradient errors ≤ 1%. Dynamite MRI provided image quality and sensitivity comparable to conventional gradient technology without any obvious artifacts. Some minor geometric deformations were noticed primarily in the image periphery as the result of regional field imperfections. The imperfections can be readily approximated theoretically through numerical integration of the Biot-Savart law and removed through image distortion correction. CONCLUSION The first realization of Dynamite MRI of the in vivo human head has been presented. The obtained image fidelity is comparable to MRI with conventional gradient coils, paving the way for full-fledged Dynamite MRI and B0 shim systems for human applications.
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dynamic multi coil technique Dynamite shimming for echo planar imaging of the human brain at 7 tesla
NeuroImage, 2015Co-Authors: Christoph Juchem, Terence W. Nixon, Umesh S Rudrapatna, Robin A De GraafAbstract:Abstract Gradient-echo echo-planar imaging (EPI) is the primary method of choice in functional MRI and other methods relying on fast MRI to image brain activation and connectivity. However, the high susceptibility of EPI towards B0 magnetic field inhomogeneity poses serious challenges. Conventional magnetic field shimming with low-order spherical harmonic (SH) functions is capable of compensating shallow field distortions, but performs poorly for global brain shimming or on specific areas with strong susceptibility-induced B0 distortions such as the prefrontal cortex (PFC). Excellent B0 homogeneity has been demonstrated recently in the human brain at 7 Tesla with the DYNAmic Multi-coIl TEchnique (Dynamite) for magnetic field shimming (J Magn Reson (2011) 212:280–288). Here, we report the benefits of Dynamite shimming for multi-slice EPI and T2* mapping. A standard deviation of 13 Hz was achieved for the residual B0 distribution in the human brain at 7 Tesla with Dynamite shimming and was 60% lower compared to conventional shimming that employs static zero through third order SH shapes. The residual field inhomogeneity with SH shimming led to an average 8 mm shift at acquisition parameters commonly used for fMRI and was reduced to 1.5-3 mm with Dynamite shimming. T2* values obtained from the prefrontal and temporal cortices with Dynamite shimming were 10-50% longer than those measured with SH shimming. The reduction of the confounding macroscopic B0 field gradients with Dynamite shimming thereby promises improved access to the relevant microscopic T2* effects. The combination of high spatial resolution and Dynamite shimming allows largely artifact-free EPI and T2* mapping throughout the brain, including prefrontal and temporal lobe areas. Dynamite shimming is expected to critically benefit a wide range of MRI applications that rely on excellent B0 magnetic field conditions including EPI-based fMRI to study various cognitive processes and assessing large-scale brain connectivity in vivo. As such, Dynamite shimming has the potential to replace conventional SH shim systems in human MR scanners.
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dynamic multi coil technique Dynamite shimming of the rat brain at 11 7 t
NMR in Biomedicine, 2014Co-Authors: Christoph Juchem, Peter B. Brown, Scott Mcintyre, Terence W. Nixon, Peter Herman, Basavaraju G Sanganahalli, Dan Green, Fahmeed Hyder, Robin A De GraafAbstract:The in vivo rat model is a workhorse in neuroscience research, preclinical studies and drug development. A repertoire of MR tools has been developed for its investigation; however, high levels of B0 magnetic field homogeneity are required for meaningful results. The homogenization of magnetic fields in the rat brain, i.e. shimming, is a difficult task because of a multitude of complex, susceptibility-induced field distortions. Conventional shimming with spherical harmonic (SH) functions is capable of compensating for shallow field distortions in limited areas, e.g. in the cortex, but performs poorly in difficult-to-shim subcortical structures or for the entire brain. Based on the recently introduced multi-coil approach for magnetic field modeling, the DYNAmic Multi-coIl TEchnique (Dynamite) is introduced for magnetic field shimming of the in vivo rat brain and its benefits for gradient-echo echo-planar imaging (EPI) are demonstrated. An integrated multi-coil/radiofrequency (MC/RF) system comprising 48 individual localized DC coils for B0 shimming and a surface transceive RF coil has been developed that allows MR investigations of the anesthetized rat brain in vivo. Dynamite shimming with this MC/RF set-up is shown to reduce the B0 standard deviation to a third of that achieved with current shim technology employing static first- through third-order SH shapes. The EPI signal over the rat brain increased by 31%, and a 24% gain in usable EPI voxels could be realized. Dynamite shimming is expected to critically benefit a wide range of preclinical and neuroscientific MR research. Improved magnetic field homogeneity, together with the achievable large brain coverage of this method, will be crucial when signal pathways, cortical circuitry or the brain's default network are studied. Together with the efficiency gains of MC-based shimming compared with SH approaches demonstrated recently, Dynamite shimming has the potential to replace conventional SH shim systems in small-bore animal scanners.
Robin A De Graaf - One of the best experts on this subject based on the ideXlab platform.
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dynamic multi coil technique Dynamite shimming for echo planar imaging of the human brain at 7 tesla
NeuroImage, 2015Co-Authors: Christoph Juchem, Terence W. Nixon, Umesh S Rudrapatna, Robin A De GraafAbstract:Abstract Gradient-echo echo-planar imaging (EPI) is the primary method of choice in functional MRI and other methods relying on fast MRI to image brain activation and connectivity. However, the high susceptibility of EPI towards B0 magnetic field inhomogeneity poses serious challenges. Conventional magnetic field shimming with low-order spherical harmonic (SH) functions is capable of compensating shallow field distortions, but performs poorly for global brain shimming or on specific areas with strong susceptibility-induced B0 distortions such as the prefrontal cortex (PFC). Excellent B0 homogeneity has been demonstrated recently in the human brain at 7 Tesla with the DYNAmic Multi-coIl TEchnique (Dynamite) for magnetic field shimming (J Magn Reson (2011) 212:280–288). Here, we report the benefits of Dynamite shimming for multi-slice EPI and T2* mapping. A standard deviation of 13 Hz was achieved for the residual B0 distribution in the human brain at 7 Tesla with Dynamite shimming and was 60% lower compared to conventional shimming that employs static zero through third order SH shapes. The residual field inhomogeneity with SH shimming led to an average 8 mm shift at acquisition parameters commonly used for fMRI and was reduced to 1.5-3 mm with Dynamite shimming. T2* values obtained from the prefrontal and temporal cortices with Dynamite shimming were 10-50% longer than those measured with SH shimming. The reduction of the confounding macroscopic B0 field gradients with Dynamite shimming thereby promises improved access to the relevant microscopic T2* effects. The combination of high spatial resolution and Dynamite shimming allows largely artifact-free EPI and T2* mapping throughout the brain, including prefrontal and temporal lobe areas. Dynamite shimming is expected to critically benefit a wide range of MRI applications that rely on excellent B0 magnetic field conditions including EPI-based fMRI to study various cognitive processes and assessing large-scale brain connectivity in vivo. As such, Dynamite shimming has the potential to replace conventional SH shim systems in human MR scanners.
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dynamic multi coil technique Dynamite shimming of the rat brain at 11 7 t
NMR in Biomedicine, 2014Co-Authors: Christoph Juchem, Peter B. Brown, Scott Mcintyre, Terence W. Nixon, Peter Herman, Basavaraju G Sanganahalli, Dan Green, Fahmeed Hyder, Robin A De GraafAbstract:The in vivo rat model is a workhorse in neuroscience research, preclinical studies and drug development. A repertoire of MR tools has been developed for its investigation; however, high levels of B0 magnetic field homogeneity are required for meaningful results. The homogenization of magnetic fields in the rat brain, i.e. shimming, is a difficult task because of a multitude of complex, susceptibility-induced field distortions. Conventional shimming with spherical harmonic (SH) functions is capable of compensating for shallow field distortions in limited areas, e.g. in the cortex, but performs poorly in difficult-to-shim subcortical structures or for the entire brain. Based on the recently introduced multi-coil approach for magnetic field modeling, the DYNAmic Multi-coIl TEchnique (Dynamite) is introduced for magnetic field shimming of the in vivo rat brain and its benefits for gradient-echo echo-planar imaging (EPI) are demonstrated. An integrated multi-coil/radiofrequency (MC/RF) system comprising 48 individual localized DC coils for B0 shimming and a surface transceive RF coil has been developed that allows MR investigations of the anesthetized rat brain in vivo. Dynamite shimming with this MC/RF set-up is shown to reduce the B0 standard deviation to a third of that achieved with current shim technology employing static first- through third-order SH shapes. The EPI signal over the rat brain increased by 31%, and a 24% gain in usable EPI voxels could be realized. Dynamite shimming is expected to critically benefit a wide range of preclinical and neuroscientific MR research. Improved magnetic field homogeneity, together with the achievable large brain coverage of this method, will be crucial when signal pathways, cortical circuitry or the brain's default network are studied. Together with the efficiency gains of MC-based shimming compared with SH approaches demonstrated recently, Dynamite shimming has the potential to replace conventional SH shim systems in small-bore animal scanners.
Pilar Llorens - One of the best experts on this subject based on the ideXlab platform.
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spatio temporal variability of the isotopic input signal in a partly forested catchment implications for hydrograph separation
Hydrological Processes, 2019Co-Authors: Carles Cayuela, Jerome Latron, Josie Geris, Pilar LlorensAbstract:This research was supported by the projects TransHyMed (CGL2016-75957-R AEI/FEDER, UE) and MASCC-Dynamite (PCIN-2017-061/AEI). C. Cayuela was beneficiary of a predoctoral FPI grant (BES-2014-070609) and a pre-doctoral mobility grant (EEBB-I-17-12493). We are grateful to G. Bertran, F. Gallart, A.J. Molina, M. Moreno de las Heras and E. Sanchez-Costa for their support during fieldwork and data analysis. We also thank all the members of the Northern Rivers Institute where part of this study was conceived. Finally, we want to thank M. Eaude for reviewing the English.