Recent advances and future perspectives on more sustainable and energy efficient distillation processes

Distillation has held a very strong position in the chemical process industries for well over a century, and has, as a separation method, been around for millennia. The process can be designed directly without the need for experimentation unlike other novel separation processes, and distillation is a standard part of any undergraduate curriculum. So why the ongoing interest in this separation dinosaur? Due to distillation’s significant importance in industry, and its associated high energy requirements and thereby contribution to global warming, considerable effort is still needed to make the process more energy efficient, as well as to consider other heating sources beyond traditional fossil fuels. In this work, we will outline the most significant methods currently considered for energy efficiency of distillation, and provide an overview of where we may be heading as a discipline in our quest for a more sustainable chemical engineering future. We will argue that significant improvements have already been made, but more is still required by both industry and legislators. We need to consider a future without the use of fossil fuel-based feedstock or energy sources and switch towards renewable sources, and our future graduates need to be adequately prepared for such a future

Three-Dimensional High-Resolution Black-Blood Magnetic Resonance Imaging for Detection of Arteritic Anterior Ischemic Optic Neuropathy in Patients With Giant Cell Arteritis

Objectives: Arteritic anterior ischemic optic neuropathy (A-AION) caused by inflammatory occlusion of the posterior ciliary arteries is the most common reason for irreversible vision loss in patients with giant cell arteritis. Atypical clinical presentation and negative funduscopy can delay systemic high-dose corticosteroid therapy to prevent impending permanent blindness and involvement of the contralateral eye. The purpose of this study was to assess the diagnostic accuracy of 3-dimensional (3D) high-resolution T1-weighted black-blood magnetic resonance imaging (T1-BB-MRI) for the detection of posterior ciliary artery involvement in patients with giant cell arteritis and funduscopic A-AION. Materials and Methods: After institutional review board approval and informed consent, 27 patients with suspected giant cell arteritis and vision disturbances were included in this monocentric prospective cohort study. Giant cell arteritis was diagnosed in 18 patients according to the diagnostic reference standard (6 men, 73.8 [69.0-78.0] years);14 of those were positive for A-AION. Precontrast and postcontrast 3D T1-BB-MRI was performed in all 27 patients. Two radiologists separately assessed image quality and local fat suppression (4-point scale), visual contrast enhancement (3-point scale), and diagnostic confidence (5-point scale) regarding arteritic posterior ciliary artery involvement. Magnetic resonance imaging findings were assessed in comparison to funduscopy. Statistical analysis included accuracy parameters and interrater agreement. Results: Sensitivity of 3D T1-BB-MRI was 92.9% (95% confidence interval, 66.1%-99.8%) and specificity was 92.3% (95% confidence interval, 64.0%-99.8%) for detection of A-AION-positive patients. Image quality and local fat suppression were assessed with 3.2 +/- 0.8 (median 3) and 3.8 +/- 0.5 (median 4). Visual contrast enhancement with 2.3 +/- 0.8 (median 3) and diagnostic confidence was rated at 4.7 +/- 0.5 (median 5). Interrater agreement was high (kappa = 0.85, P < 0.001). Three-dimensional T1-BB-MRI displayed bilateral findings in 50% of the cases, whereas only unilateral A-AION was detected in funduscopy as a possible indication for the contralateral eye at risk. Conclusions: Three-dimensional T1-BB-MRI allows accurate detection of arteritic posterior ciliary artery involvement in patients with A-AION. Further, 3D T1-BB-MRI seems to display arteritic involvement of the posterior ciliary arteries earlier than funduscopy and might, therefore, display "vision-at-risk" in patients with visual impairment and suspected giant cell arteritis but unremarkable funduscopy

Multiple Sclerosis: Improved Detection of Active Cerebral Lesions With 3-Dimensional T1 Black-Blood Magnetic Resonance Imaging Compared With Conventional 3-Dimensional T1 GRE Imaging

Objectives: The aim of this study was to assess the diagnostic accuracy of a modified high-resolution whole-brain three-dimensional T1-weighted black-blood sequence (T1-weighted modified volumetric isotropic turbo spin echo acquisition [T1-mVISTA]) in comparison to a standard three-dimensional T1-weighted magnetization-prepared rapid gradient echo (MP-RAGE) sequence for detection of contrast-enhancing cerebral lesions in patients with relapsing-remitting multiple sclerosis (MS).& para;& para;Materials and Methods: After institutional review board approval and informed consent, 22 patients (8 men;aged 31.0 +/- 9.2 years) with relapsing-remitting MS were included in this monocentric prospective cohort study.& para;& para;Contrast-enhanced T1-mVISTA and MP-RAGE, both with 0.8 mm(3) resolution, were performed in all patients. In a substudy of 12 patients, T1-mVISTA was compared with a T1-mVISTA with 1.0 mm(3) resolution (T1-mVISTA_1.0). Reference lesions were 2-defined by an experienced neuroradiologist using all available sequences and served as the criterion standard. T1-mVISTA, T1-mVISTA_1.0, and MP-RAGE sequences were read in random order 4 weeks apart. Image quality, visual contrast enhancement, contrast-to-noise-ratio (CNR), diagnostic confidence, and lesion size were assessed and compared by Wilcoxon and Mann-Whitney U tests.& para;& para;Results: Eleven of 22 patients displayed contrast-enhancing lesions. Visual contrast enhancement, CNR, and diagnostic confidence of contrast-enhancing MS lesions were significantly increased in T1-mVISTA compared with MP-RAGE (P < 0.001). Significantly more contrast-enhancing lesions were detected with T1-mVISTA than with MP-RAGE (71 vs 39, respectively;P < 0.001). With MP-RAGE, 25.6% of lesions were missed in the initial reading, whereas only 4.2% of lesions were missed with T1-mVISTA. Increase of the voxel volume from 0.8 mm to 1.0 mm isotropic in T1-mVISTA_1.0 did not affect the detect-ability of lesions, whereas scan time was decreased from 4:43 to 1:55 minutes.& para;& para;Conclusions: Three-dimensional T1-mVISTA improves the detection rates of contrast-enhancing cerebral MS lesions compared with conventional 3D MP-RAGE sequences by increasing CNR of lesions and might, therefore, be useful in patient management

T2-Weighted Dixon Turbo Spin Echo for Accelerated Simultaneous Grading of Whole-Body Skeletal Muscle Fat Infiltration and Edema in Patients With Neuromuscular Diseases

Objective The assessment of fatty infiltration and edema in the musculature of patients with neuromuscular diseases (NMDs) typically requires the separate performance of T-1-weighted and fat-suppressed T-2-weighted sequences. T-2-weighted Dixon turbo spin echo (TSE) enables the generation of T-2-weighted fat- and water-separated images, which can be used to assess both pathologies simultaneously. The present study examines the diagnostic performance of T-2-weighted Dixon TSE compared with the standard sequences in 10 patients with NMDs and 10 healthy subjects. Methods Whole-body magnetic resonance imaging was performed including T-1-weighted Dixon fast field echo, T-2-weighted short-tau inversion recovery, and T-2-weighted Dixon TSE. Fatty infiltration and intramuscular edema were rated by 2 radiologists using visual semiquantitative rating scales. To assess intermethod and interrater agreement, weighted Cohen's coefficients were calculated. Results The ratings of fatty infiltration showed high intermethod and high interrater agreement (T-1-weighted Dixon fast field echo vs T-2-weighted Dixon TSE fat image). The evaluation of edematous changes showed high intermethod and good interrater agreement (T-2-weighted short-tau inversion recovery vs T-2-weighted Dixon TSE water image). Conclusions T-2-weighted Dixon TSE imaging is an alternative for accelerated simultaneous grading of whole-body skeletal muscle fat infiltration and edema in patients with NMDs

Association of MRS-Based Vertebral Bone Marrow Fat Fraction with Bone Strength in a Human In Vitro Model

Bone marrow adiposity has recently gained attention due to its association with bone loss pathophysiology. In this study, ten vertebrae were harvested from fresh human cadavers. Trabecular BMD and microstructure parameters were extracted from MDCT. Bone marrow fat fractions were determined using single-voxel MRS. Failure load (FL) values were assessed by destructive biomechanical testing. Significant correlations (P<0.05) were observed between MRS-based fat fraction and MDCT-based parameters (up to r=-0.72) and MRS-based fat fraction and FL (r=-0.77). These findings underline the importance of the bone marrow in the pathophysiology and imaging diagnostics of osteoporosis

Dynamic fetal cardiovascular magnetic resonance imaging using Doppler ultrasound gating

Background: Fetal cardiovascular magnetic resonance (CMR) imaging may provide a valuable adjunct to fetal echocardiography in the evaluation of congenital cardiovascular pathologies. However, dynamic fetal CMR is difficult due to the lack of direct in-utero cardiac gating. The aim of this study was to investigate the effectiveness of a newly developed Doppler ultrasound (DUS) device in humans for fetal CMR gating. Methods: Fifteen fetuses (gestational age 30–39 weeks) were examined using 1.5 T CMR scanners at three different imaging sites. A newly developed CMR-compatible DUS device was used to generate gating signals from fetal cardiac motion. Gated dynamic balanced steady-state free precession images were acquired in 4-chamber and short-axis cardiac views. Gating signals during data acquisition were analyzed with respect to trigger variability and sensitivity. Image quality was assessed by measuring endocardial blurring (EB) and by image evaluation using a 4-point scale. Left ventricular (LV) volumetry was performed using the single-plane ellipsoid model. Results: Gating signals from the fetal heart were detected with a variability of 26 ± 22 ms and a sensitivity of trigger detection of 96 ± 4%. EB was 2.9 ± 0.6 pixels (4-chamber) and 2.5 ± 0.1 pixels (short axis). Image quality scores were 3.6 ± 0.6 (overall), 3.4 ± 0.7 (mitral valve), 3.4 ± 0.7 (foramen ovale), 3.6 ± 0.7 (atrial septum), 3.7 ± 0.5 (papillary muscles), 3.8 ± 0.4 (differentiation myocardium/lumen), 3.7 ± 0.5 (differentiation myocardium/lung), and 3.9 ± 0.4 (systolic myocardial thickening). Inter-observer agreement for the scores was moderate to very good (kappa 0.57–0.84) for all structures. LV volumetry revealed mean values of 2.8 ± 1.2 ml (end-diastolic volume), 0.9 ± 0.4 ml (end systolic volume), 1.9 ± 0.8 ml (stroke volume), and 69.1 ± 8.4% (ejection fraction). Conclusion: High-quality dynamic fetal CMR was successfully performed using a newly developed DUS device for direct fetal cardiac gating. This technique has the potential to improve the utility of fetal CMR in the evaluation of congenital pathologies

Holmium Nanoparticles: Preparation and In Vitro Characterization of a New Device for Radioablation of Solid Malignancies

# The Author(s) 2010. This article is published with open access at Springerlink.com Purpose The present study introduces the preparation and in vitro characterization of a nanoparticle device comprising holmium acetylacetonate for radioablation of unresectable solid malignancies. Methods HoAcAc nanoparticles were prepared by dissolving holmium acetylacetonate in chloroform, followed by emulsification in an aqueous solution of a surfactant and evaporation of W. Bult: R. Varkevisser: P. R. Luijten: A. D. van het Schip

Association of MRS-Based Vertebral Bone Marrow Fat Fraction with Bone Strength in a Human In Vitro Model

Bone marrow adiposity has recently gained attention due to its association with bone loss pathophysiology. In this study, ten vertebrae were harvested from fresh human cadavers. Trabecular BMD and microstructure parameters were extracted from MDCT. Bone marrow fat fractions were determined using single-voxel MRS. Failure load (FL) values were assessed by destructive biomechanical testing. Significant correlations ( &lt; 0.05) were observed between MRS-based fat fraction and MDCT-based parameters (up to = −0.72) and MRS-based fat fraction and FL ( = −0.77). These findings underline the importance of the bone marrow in the pathophysiology and imaging diagnostics of osteoporosis