bluuebunny/crossref_metadata_2025_split huggingface dataset:
Process flowsheet analysis of pervaporation‐based hybrid processes in the production of ethyl tert‐butyl ether
Authors: Norkobilov Adham , Gorri Daniel , Ortiz Inmaculada 
Published: December 2016

AbstractBACKGROUNDThe manufacturing process of ethyl tert‐butyl ether (ETBE) involves the separation of ETBE, mixed C4 hydrocarbons and unreacted ethanol. Unfortunately, the unreacted ethanol forms azeotropic mixtures with ETBE that are difficult to separate by distillation. One of the alternative methods to overcome this limitation is the application of hybrid distillation–pervaporation processes with alcohol‐selective membranes.RESULTSSimulation tasks were carried out with the process simulation software Aspen Plus and the results of alternative process flowsheets that result from the relative location of the separation technologies (for a target product purity) have been compared on the basis of the required membrane area and energy consumption. Thus, in the case study analyzed seven pervaporation modules located on a sidestream withdrawal, with a total membrane area of 210 m2, are required to obtain 6420 kg h−1 of ETBE with a purity of 95.2 wt%. The retentate stream is returned to the column while the permeate stream, with a high ethanol content, is recycled back to feed the reactorsCONCLUSIONIncorporating pervaporation modules in the process flowsheet for production of ETBE allows unloading of the main separation unit (debutanizer column), thereby reducing energy consumption and operating costs and increasing throughput. © 2016 Society of Chemical Industry
Regeneration of arsenic spent adsorbents by Fe/MgO nanoparticles
Authors: Simeonidis Konstantinos , Martinez‐Boubeta Carlos , Rivera-Gil Pilar , Ashraf Sumaira , Samaras Theodoros , Angelakeris Makis , Tresintsi Sofia , Mitrakas Manassis , Parak Wolfgang J , Monty Claude , Balcells Lluis 
Published: December 2016

AbstractBACKGROUNDOver recent decades, there has been increasing global concern over public health impacts related to water pollution with arsenic. With the development of nanotechnology, nanomaterials are being proposed as alternative agents for water treatment. This study focuses on the use of core‐shell nanoparticles as secondary receptors able to operate under intense conditions and perform efficient yet environmentally friendly regeneration of conventional adsorbents.RESULTSHybrid MgO‐coated Fe nanoparticles are proposed, optimized to achieve maximum arsenic uptake under a strong alkaline environment, such as the NaOH stream used to regenerate a typical oxy‐hydroxide adsorption column. The magnetic response of these nanocomposites enables their recovery and recirculation by means of an external magnetic field. A scalable laboratory continuous flow system was designed as a proof‐of‐concept to provide maximum efficiency of the recirculating nanoparticles, as well as complete reuse of the alkaline washing solution. A risk assessment scheme was conducted to evaluate the potential environmental impact of nanoparticle residues by testing the toxicity of arsenic‐loaded materials in RTgill‐W1 cells and their inertization into concrete building blocks.CONCLUSIONThe presented methodology illustrates a way to incorporate nanoparticles in water technology taking advantage of their surface activity and magnetic separation potential. © 2016 Society of Chemical Industry
Evaluation of neonatal brain myelination using the T1‐ and T2‐weighted MRI ratio
Authors: Soun Jennifer E. , Liu Michael Z. , Cauley Keith A. , Grinband Jack 
Published: December 2016

PurposeTo validate the T1‐ and T2‐weighted (T1w/T2w) MRI ratio technique in evaluating myelin in the neonatal brain.Materials and MethodsT1w and T2w MR images of 10 term neonates with normal‐appearing brain parenchyma were obtained from a single 1.5 Tesla MRI and retrospectively analyzed. T1w/T2w ratio images were created with a postprocessing pipeline and qualitatively compared with standard clinical sequences (T1w, T2w, and apparent diffusion coefficient [ADC]). Quantitative assessment was also performed to assess the ratio technique in detecting areas of known myelination (e.g., posterior limb of the internal capsule) and very low myelination (e.g., optic radiations) using linear regression analysis and the Michelson Contrast equation, a measure of luminance contrast intensity.ResultsThe ratio image provided qualitative improvements in the ability to visualize regional variation in myelin content of neonates. Linear regression analysis demonstrated a significant inverse relationship between the ratio intensity values and ADC values in the posterior limb of the internal capsule and the optic radiations (R2 = 0.96 and P < 0.001). The Michelson Contrast equation showed that contrast differences between these two regions for the ratio images were 1.6 times higher than T1w, 2.6 times higher than T2w, and 1.8 times higher than ADC (all P < 0.001). Finally, the ratio improved visualization of the corticospinal tract, one of the earliest myelinated pathways.ConclusionThe T1w/T2w ratio accentuates contrast between myelinated and less myelinated structures and may enhance our diagnostic ability to detect myelination patterns in the neonatal brain.Level of Evidence: 2Technical Efficacy: Stage2J. MAGN. RESON. IMAGING 2017;46:690–696
A novel surrogate to identify anatomical changes during radiotherapy of head and neck cancer patients
Authors: Gros Sébastien A.A. , Xu William , Roeske John C. , Choi Mehe , Emami Bahman , Surucu Murat 
Published: December 2016

PurposeTo develop a novel method to monitor external anatomical changes in head and neck cancer patients in order to triage possible adaptive radiotherapy needs.MethodsThe presented approach aims to provide information on internal anatomical changes based on variations observed in external anatomy. Setup Cone Beam Computed Tomography (CBCT) images are processed to produce an accurate external contour of the patient's skin. After registering the CBCTs to the reference planning CT, the external contours from each CBCT are transferred to the initial — first week — CBCT. Contour radii, defined as the distances between an external contour and the isocenter projection in each CBCT slice, are calculated for each scan over the full 360 degrees. The changes in external anatomy are then quantified by the difference in radial distance between the external contours of any secondary CBCT relative to the initial CBCT. Finally, the radial difference is displayed in cylindrical coordinates as a 2D intensity map to highlight regions of interests with significant changes. Weekly CBCT scans from 15 head and neck patients were retrospectively analyzed to demonstrate the utility of this approach as a proof of principle. External changes suggested by the 2D radial difference map of an example patient after 23 fractions were then correlated with the changes in the gross tumor volumes and organs at risks. The resulting dosimetric effects were evaluated. An interactive standalone software application has been developed to facilitate the generation and the interpretation of the 2D intensity map.ResultsThe 2D radial difference maps provided qualitative and quantitative information, such as the location and the magnitude of external contour changes and the rate at which these deviations occur. Out of the 15 patients, 10 presented clear evidence of general external volume shrinkage due to weight loss, and nine patients had at least one site of local shrinkage. Only two patients showed no signs of anatomical change during their entire treatment course. For the example patient, the mean (±σ) radial difference was 6.7 (±3.0) mm for the left parotid and 7.3 (±2.5) mm for the right parotid. The mean dose to the left and right parotids increased from 20.1 Gy to 30 Gy and from 16.3 Gy to 29.6 Gy, respectively.ConclusionThis novel method provides an efficient tool to visualize 3D external anatomical changes on a single 2D map. It quickly pinpoints the location of differences in anatomy during the course of radiotherapy, which can help physicians determine if a treatment plan needs to be adapted. The interactive graphic user interface developed in this study will be evaluated in an adaptive radiotherapy workflow for head and neck patients in a future prospective trial.
The relative accuracy of 4D dose accumulation for lung radiotherapy using rigid dose projection versus dose recalculation on every breathing phase
Authors: Valdes Gilmer , Lee Chul , Tenn Stephen , Lee Percy , Robinson Clifford , Iwamoto Keisuke , Low Daniel , Lamb James M. 
Published: December 2016

PurposeTo investigate the accuracy of 4D dose accumulation using projection of dose calculated on the end‐exhalation, mid‐ventilation, or average intensity breathing phase CT scan, versus dose accumulation performed using full Monte Carlo dose recalculation on every breathing phase.MethodsRadiotherapy plans for 10 patients with stage I–II lung cancer were analyzed. All patients had respiratory‐correlated computed tomography (4D‐CT) performed as part of an IRB‐approved research protocol. Stereotactic body radiotherapy (SBRT) plans were optimized using the dose calculated by a commercially available Monte Carlo algorithm on the end‐exhalation 4D‐CT phase. 4D dose accumulations using deformable registration were performed with a commercially available tool that projected the planned dose onto every breathing phase without recalculation, as well as with a Monte Carlo recalculation of the dose on all breathing phases. The 3D planned dose (3D‐EX), the 3D dose calculated on the average intensity image (3D‐AVE), and the 4D accumulations of the dose calculated on the end‐exhalation phase CT (4D‐PR‐EX), the mid‐ventilation phase CT (4D‐PR‐MID), and the average intensity image (4D‐PR‐AVE), respectively, were compared against the accumulation of the Monte Carlo dose recalculated on every phase. Plan evaluation metrics relating to target volumes and critical structures relevant for lung SBRT were analyzed.ResultsPlan evaluation metrics tabulated using 4D‐PR‐EX, 4D‐PR‐MID, and 4D‐PR‐AVE differed from those tabulated using Monte Carlo recalculation on every phase by an average of 0.14 ± 0.70 Gy, −0.11 ± 0.51 Gy, and 0.00 ± 0.62 Gy, respectively. Plan evaluation metrics calculated from 3D‐EX and 3D‐AVE were acceptably accurate for target volumes and most critical structures, however, deviations of between 8 and 13 Gy were observed for the proximal bronchial trees of three patients.ConclusionsThe accuracy of 4D dose accumulated by projecting the dose calculated on the end‐exhale, mid‐ventilation, and average intensity images has been presented for 10 lung cancer SRBT plans. These methods involving projection without recalculation may be sufficiently accurate compared to 4D dose accumulated from Monte Carlo recalculation on every phase, depending on institutional protocols. Projection of the dose calculated on the mid‐ventilation scan was found to be statistically significantly more accurate than projection of the dose calculated on end‐exhalation when considering target volume dose metrics. Use of 4D dose accumulation should be considered when evaluating normal tissue complication probabilities as well as in clinical situations where target volumes are directly inferior to mobile critical structures.
Nuclear paramagnetism‐induced MR frequency shift and its implications for MR‐based magnetic susceptibility measurement
Authors: Park Jinil , Lee Jeongtaek , Park Jang‐Yeon , Lee Seung‐Kyun 
Published: December 2016

PurposeTo investigate the 1H spin contribution (0.004 parts per million (ppm)) to the water magnetic susceptibility and discuss its implications for high‐precision phase mapping and tissue susceptibility measurement.MethodsFree induction decay (FID) signals were acquired at 3 Tesla (T) and 9.4T from thin square phantoms at a range of tip angles. The FID frequency shift was examined at a high resolution ( < 0.01 Hz) for different phantom orientations relative to the main magnetic field (B0). B0 maps on an axial and a coronal slice of a spherical phantom were obtained at 3T to examine the tip angle and orientation dependence at the 0.001 ppm level.ResultsA frequency shift of about 0.3 Hz was observed between tip angles of 10 ° and 90 ° when the thin phantom was normal to B0 at 3T, whereas the shift changed sign and was halved in magnitude when the phantom's face was parallel to B0. At 9.4T, the effect size increased proportionately. The orientation‐dependent frequency shift was also observed in the B0 map experiment. These observations agree with theoretical frequency shift due to longitudinal 1H spin polarization.ConclusionMagnetic susceptibility contribution from the nuclear paramagnetism should be taken into account in the interpretation of high‐precision phase and susceptibility mapping in MRI. Magn Reson Med 77:848–854, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Intelligent and automatic in vivo detection and quantification of transplanted cells in MRI
Authors: Afridi Muhammad Jamal , Ross Arun , Liu Xiaoming , Bennewitz Margaret F. , Shuboni Dorela D. , Shapiro Erik M. 
Published: December 2016

PurposeMagnetic resonance imaging (MRI)‐based cell tracking has emerged as a useful tool for identifying the location of transplanted cells, and even their migration. Magnetically labeled cells appear as dark contrast in T2*‐weighted MRI, with sensitivities of individual cells. One key hurdle to the widespread use of MRI‐based cell tracking is the inability to determine the number of transplanted cells based on this contrast feature. In the case of single cell detection, manual enumeration of spots in three‐dimensional (3D) MRI in principle is possible; however, it is a tedious and time‐consuming task that is prone to subjectivity and inaccuracy on a large scale. This research presents the first comprehensive study on how a computer‐based intelligent, automatic, and accurate cell quantification approach can be designed for spot detection in MRI scans.MethodsMagnetically labeled mesenchymal stem cells (MSCs) were transplanted into rats using an intracardiac injection, accomplishing single cell seeding in the brain. T2*‐weighted MRI of these rat brains were performed where labeled MSCs appeared as spots. Using machine learning and computer vision paradigms, approaches were designed to systematically explore the possibility of automatic detection of these spots in MRI. Experiments were validated against known in vitro scenarios.ResultsUsing the proposed deep convolutional neural network (CNN) architecture, an in vivo accuracy up to 97.3% and in vitro accuracy of up to 99.8% was achieved for automated spot detection in MRI data.ConclusionThe proposed approach for automatic quantification of MRI‐based cell tracking will facilitate the use of MRI in large‐scale cell therapy studies. Magn Reson Med 78:1991–2002, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Robustness of spatio‐temporal regularization in perfusion MRI deconvolution: An application to acute ischemic stroke
Authors: Giacalone Mathilde , Frindel Carole , Robini Marc , Cervenansky Frédéric , Grenier Emmanuel , Rousseau David 
Published: December 2016

PurposeThe robustness of a recently introduced globally convergent deconvolution algorithm with temporal and edge‐preserving spatial regularization for the deconvolution of dynamic susceptibility contrast perfusion magnetic resonance imaging is assessed in the context of ischemic stroke.Theory and MethodsIschemic tissues are not randomly distributed in the brain but form a spatially organized entity. The addition of a spatial regularization term allows to take into account this spatial organization contrarily to the sole temporal regularization approach which processes each voxel independently. The robustness of the spatial regularization in relation to shape variability, hemodynamic variability in tissues, noise in the magnetic resonance imaging apparatus, and uncertainty on the arterial input function selected for the deconvolution is addressed via an original in silico validation approach.ResultsThe deconvolution algorithm proved robust to the different sources of variability, outperforming temporal Tikhonov regularization in most realistic conditions considered. The limiting factor is the proper estimation of the arterial input function.ConclusionThis study quantified the robustness of a spatio‐temporal approach for dynamic susceptibility contrast‐magnetic resonance imaging deconvolution via a new simulator. This simulator, now accessible online, is of wide applicability for the validation of any deconvolution algorithm. Magn Reson Med 78:1981–1990, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Noninvasive measurement of pressure gradient across a coronary stenosis using phase contrast (PC)‐MRI: A feasibility study
Authors: Deng Zixin , Fan Zhaoyang , Lee Sang‐Eun , Nguyen Christopher , Xie Yibin , Pang Jianing , Bi Xiaoming , Yang Qi , Choi Byoung‐Wook , Kim Jung‐Sun , Berman Daniel , Chang Hyuk‐Jae , Li Debiao 
Published: December 2016

PurposeTo investigate the feasibility of blood pressure difference measurement, ΔP, across the coronary artery using phase contrast (PC)‐MRI for potential noninvasive assessment of the functional significance of coronary artery stenosis.MethodsThree‐directional velocities in the coronary arteries acquired using 2D‐PC‐MRI were used with the Navier‐Stokes equations to derive ΔP. Repeat phantom studies were performed to assess the reproducibility of flow velocity and ΔP. ΔP derived using PC‐MRI (ΔPMR) and that obtained using pressure transducer (ΔPPT) were compared. Reproducibility of coronary flow velocity was assessed in healthy controls (n = 11). Patients with suspected coronary artery disease (n = 6) were studied to evaluate the feasibility of ΔPMR measurement across a coronary stenosis.ResultsPhantom: Good overall reproducibility of flow velocity and ΔP measurements and excellent correlation (ΔPMR vs ΔPPT) was observed: intraclass correlation (ICC) of 0.95(Vz), 0.72(Vx), 0.73(Vy), and 0.87(ΔPMR) and R2 = 0.94, respectively. Human: Good reproducibility of coronary flow velocity was observed: ICC of 0.94/0.95(Vz), 0.76/0.74(Vx), and 0.80/0.77(Vy) at cardiac phase 1/2. Significant (p = 0.025) increase in ΔPMR was observed in patients (6.40 ± 4.43 mmHg) versus controls (0.70 ± 0.57 mmHg).ConclusionΔPMR in the coronary arteries is feasible. Upon further validation using the invasive measure, ΔPMR has the potential for noninvasive assessment of coronary artery stenosis. Magn Reson Med 77:529–537, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Contrast mechanisms associated with neuromelanin‐MRI
Authors: Trujillo Paula , Summers Paul E. , Ferrari Emanuele , Zucca Fabio A. , Sturini Michela , Mainardi Luca T. , Cerutti Sergio , Smith Alex K. , Smith Seth A. , Zecca Luigi , Costa Antonella 
Published: December 2016

PurposeTo investigate the physical mechanisms associated with the contrast observed in neuromelanin MRI.MethodsPhantoms having different concentrations of synthetic melanins with different degrees of iron loading were examined on a 3 Tesla scanner using relaxometry and quantitative magnetization transfer (MT).ResultsConcentration‐dependent T1 and T2 shortening was most pronounced for the melanin pigment when combined with iron. Metal‐free melanin had a negligible effect on the magnetization transfer spectra. On the contrary, the presence of iron‐laden melanins resulted in a decreased magnetization transfer ratio. The presence of melanin or iron (or both) did not have a significant effect on the macromolecular content, represented by the pool size ratio.ConclusionThe primary mechanism underlying contrast in neuromelanin‐MRI appears to be the T1 reduction associated with melanin‐iron complexes. The macromolecular content is not significantly influenced by the presence of melanin with or without iron, and thus the MT is not directly affected. However, as T1 plays a role in determining the MT‐weighted signal, the magnetization transfer ratio is reduced in the presence of melanin‐iron complexes. Magn Reson Med 78:1790–1800, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Multiparametric estimation of brain hemodynamics with MR fingerprinting ASL
Authors: Su Pan , Mao Deng , Liu Peiying , Li Yang , Pinho Marco C. , Welch Babu G. , Lu Hanzhang 
Published: December 2016

PurposeAssessment of brain hemodynamics without exogenous contrast agents is of increasing importance in clinical applications. This study aims to develop an MR perfusion technique that can provide noncontrast and multiparametric estimation of hemodynamic markers.MethodsWe devised an arterial spin labeling (ASL) method based on the principle of MR fingerprinting (MRF), referred to as MRF‐ASL. By taking advantage of the rich information contained in MRF sequence, up to seven hemodynamic parameters can be estimated concomitantly. Feasibility demonstration, flip angle optimization, comparison with Look‐Locker ASL, reproducibility test, sensitivity to hypercapnia challenge, and initial clinical application in an intracranial steno‐occlusive process, Moyamoya disease, were performed to evaluate this technique.ResultsMagnetic resonance fingerprinting ASL provided estimation of up to seven parameters, including
, tissue T1, cerebral blood flow (CBF), tissue bolus arrival time (BAT), pass‐through arterial BAT, pass‐through blood volume, and pass‐through blood travel time. Coefficients of variation of the estimated parameters ranged from 0.2 to 9.6%. Hypercapnia resulted in an increase in CBF by 57.7%, and a decrease in BAT by 13.7 and 24.8% in tissue and vessels, respectively. Patients with Moyamoya disease showed diminished CBF and lengthened BAT that could not be detected with regular ASL.ConclusionMagnetic resonance fingerprinting ASL is a promising technique for noncontrast, multiparametric perfusion assessment. Magn Reson Med 78:1812–1823, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
Encapsulation of imidazole with synthesized copolymers for latent curing of epoxy resin
Authors: Shin Young Jae , Shin Min Jae , Shin Jae Sup 
Published: December 2016

AbstractAnisotropic conductive film (ACF) is an essential component in the manufacture of liquid crystal displays, and an imidazole–epoxy resin system that exhibits a latent behavior is generally used as an adhesive in the ACF. In this study, a new copolymer was synthesized using methacrylic acid and dodecyl methacrylate, and this copolymer was used to encapsulate an imidazole curing agent to endow the ACF with latent behavior. A spray‐drying method was used in the encapsulation process, and this encapsulated imidazole was mixed with epoxy resin to form an imidazole–epoxy resin system. A comparison with our previous results showed that a smaller amount of polymeric material could be used in the encapsulating process, and a superior latent behavior could be obtained. © 2016 Society of Chemical Industry
Synthesis and conjugation of a triiodohydroxylamine for the preparation of highly X‐ray opaque poly(ε‐caprolactone) materials
Authors: Van Horn Brooke A. , Davis Lundy L. , Nicolau Samantha E. , Burry Emma E. , Bailey Victoria O. , Guerra Fernanda D. , Alexis Frank , Whitehead Daniel C. 
Published: December 2016

ABSTRACTTo address a need for highly X‐ray opaque biodegradable materials, a series of poly(ε‐caprolactone) derivatives were prepared using oxime post‐polymerization modification to conjugate two different iodinated hydroxylamines. These materials were synthesized with up to 32 wt. % iodine content and demonstrated improved X‐ray contrast relative to both the ketone precursors and previously reported monoiodinated materials. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 787–793