Publications by authors named "S Simon"

2,724 Publications

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Emulsions in external electric fields.

Adv Colloid Interface Sci 2021 May 30;294:102455. Epub 2021 May 30.

Ugelstad Laboratory, Norwegian University of Science and Technology, 7491 Trondheim, Norway; Anvendt Teknologi AS, Munkvollvegen 56, 7022 Trondheim, Norway.

Water is co-produced with crude oils, generally in the form of water-in-crude oil emulsions. The oil and water phases need to be separated before export. Separation is performed in gravity separators with the addition of chemical demulsifiers and, sometimes, with the application of an electric field by using an electrocoalescer. The present article reviews several aspects of electrocoalescence by considering the effect of the electric field from the molecular to a macroscopic scale: the oil-water interface, single drop effects, two drop interactions, and finally emulsions at laboratory scales. Experimental results together with Dissipative Particle Dynamics (DPD) simulation results are presented. The review begins with water-oil interface under an electric field and followed by single drop electrohydrodynamics. The electric field is shown to influence the adsorption of crude oil indigenous surface-active components (asphaltenes) due to the electrohydrodynamic (EHD) flows. The interactions between two droplets in the presence of electric field and the factors governing the drop-drop coalescence are discussed in detail. DPD simulations help to elucidate thin film breakup during (electro)-coalescence of two water droplets, where the oil film has drained out to nanometer thickness. The film is comprised of surfactant and demulsifier molecules, and the simulations capture the pores formation in the film when a DC field is applied. The results demonstrate influence of the molecular structure of the surfactant and demulsifier, and their interactions. The subsequent section describes experimental techniques to assess the resolution of crude oil emulsions at the laboratory scale. The focus is on low-field Nuclear Magnetic Resonance (LF-NMR) which allows a determination of various emulsion features such as the droplet size distribution (DSD) and the brine profile (variation of the concentration of water with the height of the emulsion sample) and their evolution with time. Application of the technique in emulsion treatment involving chemical demulsifiers and electric field is presented. The review concludes with description of commercial industrial electrocoalecers such as the Vessel Internal Electrostatic Coalescer (VIEC) and the Compact Electrostatic Coalescer (CEC).
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http://dx.doi.org/10.1016/j.cis.2021.102455DOI Listing
May 2021

The Spatiotemporal Dynamics and Microevolution Events That Favored the Success of the Highly Clonal Multidrug-Resistant Monophasic Circulating in Europe.

Front Microbiol 2021 21;12:651124. Epub 2021 May 21.

Department of Bacteriology, Animal and Plant Health Agency, Addlestone, United Kingdom.

The European epidemic monophasic variant of enterica serovar (. 1,4,[5],12:i:-) characterized by the multi sequence type ST34 and the antimicrobial resistance ASSuT profile has become one of the most common serovars in Europe (EU) and the United States (US). In this study, we reconstructed the time-scaled phylogeny and evolution of this in Europe. The epidemic . 1,4,[5],12:i:- ST34 emerged in the 1980s by an acquisition of the Genomic Island (SGI)-4 at the 3' end of the phenylalanine tRNA conferring resistance to copper and arsenic toxicity. Subsequent integration of the Tn21 transposon into the gave resistance to mercury toxicity and several classes of antibiotics used in food-producing animals (ASSuT profile). The second step of the evolution occurred in the 1990s, with the integration of mTmV and mTmV-like prophages carrying the and/or genes involved in the ability to reduce nitrates in intestinal contents and facilitate the disruption of the junctions of the host intestinal epithelial cells. Heavy metals are largely used as food supplements or pesticide for cultivation of seeds intended for animal feed so the expansion of the epidemic 1,4,[5],12:i:- ST34 was strongly related to the multiple-heavy metal resistance acquired by transposons, integrative and conjugative elements and facilitated by the escape until 2011 from the regulatory actions applied in the control of Typhimurium in Europe. The genomic plasticity of the epidemic 1,4,[5],12:i:- was demonstrated in our study by the analysis of the plasmidome. We were able to identify plasmids harboring genes mediating resistance to phenicols, colistin, and fluoroquinolone and also describe for the first time in six of the analyzed genomes the presence of two plasmids (pERR1744967-1 and pERR2174855-2) previously described only in strains of enterotoxigenic and .
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http://dx.doi.org/10.3389/fmicb.2021.651124DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8175864PMC
May 2021

Burden and Needs of Patients with Severe GvHD from the Supportive and Palliative Care Perspective-A Literature Review.

Cancers (Basel) 2021 May 30;13(11). Epub 2021 May 30.

Department of Palliative Medicine, University Hospital and Faculty of Medicine, University of Cologne, 50937 Cologne, Germany.

Graft-versus-host disease (GvHD) is a frequent, and often life-threatening, complication after an allogeneic, hematopoietic stem cell transplantation (allo-SCT). It can appear in an acute or a chronic form and presents different grades of severity. Particularly, the severe forms of GvHD are often responsible for a change of the curative intent for allo-SCT into a palliative goal of care. For this non-systematic review, we conducted a focused literature search in the MEDLINE database via PubMed to examine whether patients with severe forms of GvHD might have special needs and burdens from a supportive and palliative care perspective. To draw a comprehensive picture of this patient group, we included findings on quality of life (QoL) and physical symptoms and function as well as psychological and spiritual well-being. In most domains, patients with severe forms of GvHD showed greater impairment and a higher symptom burden compared to patients with milder forms of GvHD. However, we could not identify any studies that specifically investigated patients with severe forms of GvHD. Further research in this field is necessary to guarantee the highest standard of care for this very special patient group.
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http://dx.doi.org/10.3390/cancers13112697DOI Listing
May 2021

FDRN: A Fast Deformable Registration Network for Medical Images.

Med Phys 2021 May 30. Epub 2021 May 30.

Institute of Parallel and Distributed Systems, University of Stuttgart, Stuttgart, Germany.

Purpose: Deformable image registration is a fundamental task in medical imaging. Due to the large computational complexity of deformable registration of volumetric images, conventional iterative methods usually face the tradeoff between the registration accuracy and the computation time in practice. In order to boost the performance of deformable registration in both accuracy and runtime, we propose a fast unsupervised convolutional neural network for deformable image registration.

Methods: The proposed registration model FDRN possesses a compact encoder-decoder network architecture which employs a pair of fixed and moving images as input and outputs a three dimensional displacement vector field (DVF) describing the offsets between the corresponding voxels in the fixed and moving images. In order to efficiently utilize the memory resources and enlarge the model capacity, we adopt additive forwarding instead of channel concatenation and deepen the network in each encoder and decoder stage. To facilitate the learning efficiency, we leverage skip connection within the encoder and decoder stages to enable residual learning and employ an auxiliary loss at the bottom layer with lowest resolution to involve deep supervision. Particularly, the low-resolution auxiliary loss is weighted by an exponentially decayed parameter during the training phase. In conjunction with the main loss in high-resolution grid, a coarse-to-fine learning strategy is achieved. Last but not least, we involve a proposed multi-label segmentation loss to improve the network performance in Dice score in case the segmentation prior is available. Comparing to the segmentation loss using average Dice score, the proposed segmentation loss does not require additional memory in the training phase and improves the registration accuracy efficiently.

Results: We evaluated FDRN on multiple brain MRI datasets from different aspects including registration accuracy, model generalizability, and model analysis. Experimental results demonstrate that FDRN performs better than the state-of-the-art registration method VoxelMorph by 1.46% in Dice score in LPBA40. In addition to LPBA40, FDRN obtains the best Dice and NCC among all the investigated methods in the unseen MRI datasets including CUMC12, MGH10, ABIDE, and ADNI by a large margin.

Conclusions: The proposed FDRN provides better performance than the existing state-of-the-art registration methods for brain MR images by resorting to the compact autoencoder structure and efficient learning. Additionally, FDRN is a generalized framework for image registration which is not confined to a particular type of medical images or anatomy.
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http://dx.doi.org/10.1002/mp.15011DOI Listing
May 2021

Incremental Value of Three-Phase Bone Scintigraphy and Single-Photon Emission Computed Tomography-Computed Tomography in a Case of Postpartum PUO in the Wake of The Antibiotic-Resistance Era.

Indian J Nucl Med 2021 Jan-Mar;36(1):62-65. Epub 2021 Mar 4.

Department of Nuclear Medicine and Molecular Imaging, Apollo Hospitals, Chennai, Tamil Nadu, India.

Postpartum methicillin-resistant (MRSA) infection occurs in patients with complicated vaginal delivery or cesarean section. The infection can manifest as mastitis, endometritis, and if untreated may lead to toxic shock syndrome. We report a case of postpartum MRSA osteomyelitis diagnosed by 99mtechnetium-methylene diphosphonate skeletal scintigraphy and single-photon emission computed tomography-computed tomography (CT) that was further confirmed by magnetic resonance imaging and CT-guided biopsy. This multimodal imaging approach helped reach the diagnosis and in further management of the patient.
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http://dx.doi.org/10.4103/ijnm.IJNM_168_20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8130677PMC
March 2021