26,060 results match your criteria diffusion coefficient

Electrochemical reduction of O2 in Ca2+ containing DMSO - Role of roughness and single crystal structure.

ChemSusChem 2021 Apr 21. Epub 2021 Apr 21.

University of Bonn, Inst. f. Physikalische u.Theoret. Chemie, R�merstra�e 164, -Abteilung Elektrochemie-, 53117, Bonn, GERMANY.

This work compares the oxygen reduction reaction (ORR) in Ca2+ containing dimethyl sulfoxide (DMSO) at well-ordered and rough electrode surfaces using cyclic voltammetry, differential electrochemical mass spectrometry (DEMS), rotating ring disk electrode (RRDE) and atomic force microscopy (AFM). Slightly soluble CaO2 is the main product during early ORR on gold electrodes; after completion of a monolayer of CaO and/or CaO2, which is formed in parallel and in competition to the peroxide, only superoxide is formed. When the monolayer is completely closed on smooth annealed Au no further reduction occurs, whereas on rough Au a defect - rich layer allows for continuous formation of superoxide. Read More

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Penumbra quantification from MR SWI-DWI mismatch and its comparison with MR ASL PWI-DWI mismatch in patients with acute ischemic stroke.

NMR Biomed 2021 Apr 20:e4526. Epub 2021 Apr 20.

Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India.

In acute-ischemic-stroke patients, penumbra assessment plays a significant role in treatment outcome. MR perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) mismatch ratio can provide penumbra assessment. Recently reported studies have shown the potential of susceptibility-weighted imaging (SWI) in the qualitative assessment of penumbra. Read More

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Low conductivity on electrical properties tomography demonstrates unique tumor habitats indicating progression in glioblastoma.

Eur Radiol 2021 Apr 20. Epub 2021 Apr 20.

Department of Tomographic Imaging, Philips Research Laboratories, Hamburg, Germany.

Objectives: Tissue conductivity measurements made with electrical properties tomography (EPT) can be used to define temporal changes in tissue habitats on longitudinal multiparametric MRI. We aimed to demonstrate the added insights for identifying tumor habitats obtained by including EPT with diffusion- and perfusion-weighted MRI, and to evaluate the use of these tumor habitats for determining tumor treatment response in post-treatment glioblastoma.

Methods: Tumor habitats were developed from EPT, diffusion-weighted, and perfusion-weighted MRI in 60 patients with glioblastoma who underwent concurrent chemoradiotherapy. Read More

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Alteration of brain connectivity in neurologically asymptomatic patients with chronic kidney disease.

Medicine (Baltimore) 2021 Apr;100(16):e25633

Department of Internal Medicine.

Abstract: Our previous study demonstrated that patients with end-stage renal disease had decreased structural and functional brain connectivity, and there was a significant association between brain connectivity and cognitive function. The aim of this study was to evaluate the alterations of structural and functional connectivity using graph theoretical analysis in neurologically asymptomatic patients with relatively early-stage chronic kidney disease (CKD).We enrolled 18 neurologically asymptomatic patients with early CKD and 28 healthy controls. Read More

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[Predictive value of combination of MRI tumor regression grade and apparent diffusion coefficient for pathological complete remission after neoadjuvant treatment of locally advanced rectal cancer].

Zhonghua Wei Chang Wai Ke Za Zhi 2021 Apr;24(4):359-365

Medical Imaging Center, the First Affiliate Hospital, Kunming Medical University, Kunming 650032, China.

Pelvic high-resolution magnetic resonance imaging (MRI) has now become a standard method for evaluating the efficacy of neoadjuvant treatment for locally advanced rectal cancer (LARC). However, this traditional morphological qualitative assessment method based on T2-weighted imaging (T2WI) is not effective in predicting pathological complete remission (pCR). The purpose of this study is to investigate whether combining the magnetic resonance tumor regression grade (mrTRG) with apparent diffusion coefficient (ADC) can improve diagnostic value for pCR after preoperative neoadjuvant chemoradiotherapy (nCRT) of LARC. Read More

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Fast and slow effective waves across dilute random distributions of elastic spheres in a poroelastic medium.

Ultrasonics 2021 Apr 9;115:106432. Epub 2021 Apr 9.

Département de Mathématiques, Université de Lomé, Togo.

A dilute random distribution of identical elastic spheres in a poroelastic isotropic matrix obeying Biot's theory is considered. Using Luppe, Conoir and Norris (LCN) multiple scattering formula up to the corrective second order term in concentration, approximations are sought in the low frequency domain (Rayleigh limit) for the fast and slow effective wavenumbers. The contribution of the corrective second order term - which contains the coupling (i. Read More

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Natural Course of the Diffusion Capacity for Carbon Monoxide in COPD: Importance of Sex.

Chest 2021 Apr 17. Epub 2021 Apr 17.

Pulmonary and Critical Care Department, Brigham and Women's Hospital, Boston, MA, USA.

Background: The value of the single breath diffusion capacity for carbon monoxide (DLco) relates to outcomes in COPD patients. However, little is known about the natural course of DLco over time, the intersubject variability and the factors that may influence DLco progression.

Research Question: What is the natural course of DLco in COPD patients over time, and which other factors, including sex differences could influence this progression?

Study Design And Methods: We phenotyped 602 smokers (33% women) of which 506 (84%) had COPD and 96 (16%) had no airflow limitation. Read More

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Cortically constrained shape recognition: Automated white matter tract segmentation validated in the pediatric brain.

J Neuroimaging 2021 Apr 20. Epub 2021 Apr 20.

Department of Neurology, University of California, UCSF Memory and Aging Center, Sandler Neurosciences Center, San Francisco, California, USA.

Background And Purpose: Manual segmentation of white matter (WM) bundles requires extensive training and is prohibitively labor-intensive for large-scale studies. Automated segmentation methods are necessary in order to eliminate operator dependency and to enable reproducible studies. Significant changes in the WM landscape throughout childhood require flexible methods to capture the variance across the span of brain development. Read More

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Diffusion-weighted magnetic resonance imaging of mandibular bone marrow: do apparent diffusion coefficient values of the cervical vertebrae and mandible correlate with age?

Oral Radiol 2021 Apr 20. Epub 2021 Apr 20.

Department of Stomatology, School of Dentistry, University of São Paulo, 2227 Lineu Prestes Avenue, São Paulo, SP, 05508-000, Brazil.

Objectives: The objective of this investigation was to assess the correlation between the mandible and cervical vertebrae bone marrow apparent diffusion coefficient (ADC), obtained by diffusion-weighted magnetic resonance imaging (DWI), with age; to verify the correlation between ADC values from the mandible and the cervical vertebrae; to describe and assess the differences between ADC values obtained from DWI examinations of distinct mandible areas as well as cervical vertebrae.

Methods: Thirty imaging examinations with DWI for that included the mandible and C1, C2, C3, and C4 vertebrae in the same examination were included. ADC values were collected from 7 distinct areas in the mandible and the cervical vertebrae. Read More

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Identifying lumbosacral plexus nerve root abnormalities in patients with sciatica using 3T readout-segmented echo-planar diffusion weighted MR neurography.

Insights Imaging 2021 Apr 20;12(1):54. Epub 2021 Apr 20.

Department of Radiology, Mater Misericordiae University Hospital, Eccles Street, Dublin7, Dublin, Ireland.

Objectives: To investigate the accuracy of Diffusion Weighted Imaging (DWI) using the Readout Segmentation of Long Variable Echo-trains (RESOLVE) sequence in detecting lumbosacral nerve abnormalities.

Methods: Following institutional ethics committee approval, patients with sciatica-type lower limb radicular symptoms (n = 110) were recruited and prospectively scanned using 3T MRI. Additional participants (n = 17) who underwent neurophysiological testing (EMG/NCV), were also prospectively studied. Read More

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Prognostic Value of Apparent Diffusion Coefficient in Oropharyngeal Carcinoma.

Clin Neuroradiol 2021 Apr 20. Epub 2021 Apr 20.

Radiology, HUS Diagnostic Center, University of Helsinki and Helsinki University Hospital, Haartmaninkatu 4, 00029 HUS, Helsinki, Finland.

Purpose: To investigate clinical and radiological factors predicting worse outcome after (chemo)radiotherapy ([C]RT) in oropharyngeal squamous cell carcinoma (OPSCC) with a focus on apparent diffusion coefficient (ADC).

Methods: This retrospective study included 67 OPSCC patients, treated with (C)RT with curative intent and diagnosed during 2013-2017. Human papilloma virus (HPV) association was detected with p16 immunohistochemistry. Read More

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Nomogram development and validation to predict hepatocellular carcinoma tumor behavior by preoperative gadoxetic acid-enhanced MRI.

Eur Radiol 2021 Apr 20. Epub 2021 Apr 20.

Department of Radiology, The First Affiliated Hospital, Sun Yat-sen University, 58 Zhongshan Road 2, Guangzhou, 510080, China.

Objectives: Pretreatment evaluation of tumor biology and microenvironment is important to predict prognosis and plan treatment. We aimed to develop nomograms based on gadoxetic acid-enhanced MRI to predict microvascular invasion (MVI), tumor differentiation, and immunoscore.

Methods: This retrospective study included 273 patients with HCC who underwent preoperative gadoxetic acid-enhanced MRI. Read More

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Ultrasmall LiS-Carbon Nanotube Nanocomposites for High-Rate All-Solid-State Lithium-Sulfur Batteries.

ACS Appl Mater Interfaces 2021 Apr 20. Epub 2021 Apr 20.

Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, P. R. China.

Due to the intrinsic poor ionic/electronic conductivities of LiS, it is a great challenge to realize high-rate all-solid-state lithium-sulfur batteries (ASSLSBs) with long cyclic performance. Herein, ultrasmall LiS (∼15 nm) is evenly deposited on a carbon nanotube (CNT) a facile liquid-phase method to address these issues. The unique structure of the LiS deposited on a CNT composite cathode can improve ionic/electronic conductivities of LiS effectively and relieve the generated internal stress/strain during cycling. Read More

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Tissue clearing techniques for three-dimensional optical imaging of intact human prostate and correlations with multi-parametric MRI.

Prostate 2021 Apr 20. Epub 2021 Apr 20.

Medical Artificial Intelligence Laboratory Program, The University of Hong Kong, Hong Kong, Hong Kong SAR.

Background: Tissue clearing technologies have enabled remarkable advancements for in situ characterization of tissues and exploration of the three-dimensional (3D) relationships between cells, however, these studies have predominantly been performed in non-human tissues and correlative assessment with clinical imaging has yet to be explored. We sought to evaluate the feasibility of tissue clearing technologies for 3D imaging of intact human prostate and the mapping of structurally and molecularly preserved pathology data with multi-parametric volumetric MR imaging (mpMRI).

Methods: Whole-mount prostates were processed with either hydrogel-based CLARITY or solvent-based iDISCO. Read More

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The diagnostic value of intravoxel incoherent motion imaging in differentiating high-grade from low-grade gliomas: a systematic review and meta-analysis.

Br J Radiol 2021 May;94(1121):20201321

Department of Radiology, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.

Objective: This meta-analysis was carried out for assessing the accuracy of intravoxel incoherent motion (IVIM) parameters true diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f) in differentiating low-grade gliomas (LGGs) from high-grade gliomas (HGGs).

Methods: Literatures concerning IVIM in the grading of brain gliomas published prior to October 20, 2020, searched in the Embase, PubMed, and Cochrane library. Use the quality assessment of diagnostic accuracy studies 2 (QUADAS 2) to evaluate the quality of studies. Read More

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A ternary mixture at the border of Soret separation stability.

Phys Chem Chem Phys 2021 Apr 25;23(14):8466-8477. Epub 2021 Mar 25.

Institute of Continuous Media Mechanics UB RAS, Perm, Russia.

Ternary mixtures with the Soret effect are prone to triple-diffusive convection in a thermal field. The Soret coefficients of the toluene-methanol-cyclohexane mixture, measured in microgravity at a given composition [0.62-0. Read More

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Image-based personalization of computational models for predicting response of high-grade glioma to chemoradiation.

Sci Rep 2021 Apr 19;11(1):8520. Epub 2021 Apr 19.

Department of Radiation Oncology, MD Anderson Cancer Center, Houston, TX, USA.

High-grade gliomas are an aggressive and invasive malignancy which are susceptible to treatment resistance due to heterogeneity in intratumoral properties such as cell proliferation and density and perfusion. Non-invasive imaging approaches can measure these properties, which can then be used to calibrate patient-specific mathematical models of tumor growth and response. We employed multiparametric magnetic resonance imaging (MRI) to identify tumor extent (via contrast-enhanced T-weighted, and T-FLAIR) and capture intratumoral heterogeneity in cell density (via diffusion-weighted imaging) to calibrate a family of mathematical models of chemoradiation response in nine patients with unresected or partially resected disease. Read More

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Application of the diffusion equation for modelling splash dispersal of point-source pathogens.

New Phytol 1991 Jun;118(2):295-301

Application Technology Research Unit, United States Department of Agriculture/Agricultural Research Service, Wooster, Ohio 44691, USA.

A model of splash dispersal of point-source pathogens is developed and parameterized from experimental data of Colletotrichum acutatum, the cause of strawberry anthracnose. Starting with analysis on a probability density function of a sum of random displacement vectors, the model turned out to be the fundamental solution of the classic diffusion equation. Model parameters were determined for three ground covers (plastic, soil, and straw) and two rain intensities (15 and 30 mm h ). Read More

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Investigating DWI changes in white matter of meningioma patients treated with proton therapy.

Phys Med 2021 Apr 16;84:72-79. Epub 2021 Apr 16.

Department of Electronics, Information and Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy. Electronic address:

Purpose: To evaluate changes in diffusion and perfusion-related properties of white matter (WM) induced by proton therapy, which is capable of a greater dose sparing to organs at risk with respect to conventional X-ray radiotherapy, and to eventually expose early manifestations of delayed neuro-toxicities.

Methods: Apparent diffusion coefficient (ADC) and IVIM parameters (D, D* and f) were estimated from diffusion-weighted MRI (DWI) in 46 patients affected by meningioma and treated with proton therapy. The impact on changes in diffusion and perfusion-related WM properties of dose and time, as well as the influence of demographic and pre-treatment clinical information, were investigated through linear mixed-effects models. Read More

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Dynamic heterogeneity, cooperative motion, and Johari-Goldstein [Formula: see text]-relaxation in a metallic glass-forming material exhibiting a fragile-to-strong transition.

Eur Phys J E Soft Matter 2021 Apr 19;44(4):56. Epub 2021 Apr 19.

Material Measurement Laboratory, Materials Science and Engineering Division, National Institute of Standards and Technology(NIST), Gaithersburg, MD, 20899, USA.

We investigate the Johari-Goldstein (JG) [Formula: see text]-relaxation process in a model metallic glass-forming (GF) material ([Formula: see text]), previously studied extensively by both frequency-dependent mechanical measurements and simulation studies devoted to equilibrium properties, by molecular dynamics simulations based on validated and optimized interatomic potentials with the primary aim of better understanding the nature of this universal relaxation process from a dynamic heterogeneity (DH) perspective. The present relatively low temperature and long-time simulations reveal a direct correspondence between the JG [Formula: see text]-relaxation time [Formula: see text] and the lifetime of the mobile particle clusters [Formula: see text], defined as in previous DH studies, a relationship dual to the corresponding previously observed relationship between the [Formula: see text]-relaxation time [Formula: see text] and the lifetime of immobile particle clusters [Formula: see text]. Moreover, we find that the average diffusion coefficient D nearly coincides with [Formula: see text] of the smaller atomic species (Al) and that the 'hopping time' associated with D coincides with [Formula: see text] to within numerical uncertainty, both trends being in accord with experimental studies. Read More

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Intermediate scattering functions of a rigid body monoclonal antibody protein in solution studied by dissipative particle dynamic simulation.

Struct Dyn 2021 Mar 8;8(2):024102. Epub 2021 Apr 8.

NIST Center for Neutron Research, National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899, USA.

In the past decade, there was increased research interest in studying internal motions of flexible proteins in solution using Neutron Spin Echo (NSE) as NSE can simultaneously probe the dynamics at the length and time scales comparable to protein domain motions. However, the collective intermediate scattering function (ISF) measured by NSE has the contributions from translational, rotational, and internal motions, which are rather complicated to be separated. Widely used NSE theories to interpret experimental data usually assume that the translational and rotational motions of a rigid particle are decoupled and independent to each other. Read More

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Intermuscular Fat Content in Young Chinese Men With Newly Diagnosed Type 2 Diabetes: Based on MR mDIXON-Quant Quantitative Technique.

Front Endocrinol (Lausanne) 2021 30;12:536018. Epub 2021 Mar 30.

Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, China.

Objective: Skeletal muscle fat content is one of the important contributors to insulin resistance (IR), but its diagnostic value remains unknown, especially in the Chinese population. Therefore, we aimed to analyze differences in skeletal muscle fat content and various functional MRI parameters between diabetic patients and control subjects to evaluate the early indicators of diabetes. In addition, we aimed to investigate the associations among skeletal muscle fat content, magnetic resonance parameters of skeletal muscle function and IR in type 2 diabetic patients and control subjects. Read More

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Optimal Organization of Functional Connectivity Networks for Segregation and Integration With Large-Scale Critical Dynamics in Human Brains.

Front Comput Neurosci 2021 31;15:641335. Epub 2021 Mar 31.

School of Mathematical Sciences and Centre for Computational Systems Biology, Fudan University, Shanghai, China.

The optimal organization for functional segregation and integration in brain is made evident by the "small-world" feature of functional connectivity (FC) networks and is further supported by the loss of this feature that has been described in many types of brain disease. However, it remains unknown how such optimally organized FC networks arise from the brain's structural constrains. On the other hand, an emerging literature suggests that brain function may be supported by critical neural dynamics, which is believed to facilitate information processing in brain. Read More

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Role of diffusion-weighted MRI in differentiating between benign and malignant bone lesions: a prospective study.

Clin Radiol 2021 Apr 14. Epub 2021 Apr 14.

Radio-diagnosis Department, Faculty of Medicine, South Valley University, Qena, Egypt.

Aim: To evaluate the ability of diffusion-weighted magnetic resonance imaging (DW-MRI) to differentiate between benign and malignant bony tumours.

Materials And Methods: This prospective study was conducted from October, 2018 to December, 2019. The study included 62 patients (37 male and 25 female) with clinically suspected bony lesions referred to the Radiology Department. Read More

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MRI diffusion phantoms: ADC and relaxometric measurement comparisons between polyacrylamide and agarose gels.

Eur J Radiol 2021 Apr 8;139:109696. Epub 2021 Apr 8.

Department of Medical Physics, University of Crete, Heraklion, Crete, Greece; Computational BioMedicine Laboratory, Institute of Computer Science, Foundation for Research and Technology-Hellas (FORTH), Heraklion, Crete, Greece. Electronic address:

Purpose: The aim of this study is to compare polyacrylamide and agarose gels, as components of a simple MRI phantom, for the measurements of Apparent Diffusion Coefficient (ADC), T1 and T2 relaxation times.

Materials And Methods: Five (5) test tubes with polyacrylamide gels of different monomer concentrations and six (6) test tubes of different agarose gel concentrations were used as a phantom for ADC, T1 and T2 measurements, which were expressed as 2D color parametric maps, on a 1.5 T clinical MRI system. Read More

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Determination of the size of lipid rafts studied through single-molecule FRET simulations.

Biophys J 2021 Apr 14. Epub 2021 Apr 14.

Biological Physics Laboratory, Physics Institute, Universidad Autónoma de San Luis Potosí, Álvaro Obregón 64, San Luis Potosí, S.L.P. 78290, Mexico. Electronic address:

Fluorescence Resonance Energy Transfer (FRET) is a high resolution technique that allows the characterization of spatial and temporal properties of biological structures and mechanisms. In the present work, we developed an in silico single-molecule FRET methodology to study the dynamics of fluorophores inside lipid rafts. We monitored the fluorescence of a single acceptor molecule in the presence of several donor molecules. Read More

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Study of the premicellar state in aqueous solutions of sodium dodecyl sulfate by NMR diffusion.

Magn Reson Chem 2021 Apr 17. Epub 2021 Apr 17.

Chemistry of Interfaces, Luleå University of Technology, SE-97187, Luleå, Sweden.

Self-diffusion coefficients of sodium dodecyl sulfate (SDS) were measured in aqueous solutions in the premicellar range of the SDS concentrations 7-34.7 mM and temperatures 30-90 C. Average effective hydrodynamic radii and aggregation numbers of SDS in the premicellar region were determined. Read More

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Effects of air-impingement jet drying on drying kinetics, color, polyphenol compounds, and antioxidant activities of Boletus aereus slices.

J Food Sci 2021 Apr 16. Epub 2021 Apr 16.

School of Advanced Agriculture and Bioengineering, Yangtze Normal University, Chongqing, China.

The aim of the study is to interpret the effects of air-impingement jet drying (AIJD) on drying kinetics, color, polyphenols, and antioxidation ability of Boletus aereus slices. Page model was most suitable for expressing and predicting AIJD curves of B. aereus slices. Read More

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Investigation of Quercetin interaction behaviors with lipid bilayers: Toward understanding its antioxidative effect within biomembrane.

J Biosci Bioeng 2021 Apr 13. Epub 2021 Apr 13.

Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan. Electronic address:

Quercetin (QCT), existing in common dietary sources, is an abundant bioflavonoid with planar structure and exerts multiple pharmacological effects. Herein, four kinds of liposomes were prepared as model biomembranes, and then the partition coefficient, distribution in lipid membrane and influence of the QCT on the membrane properties were evaluated. The partition of QCT to lipid membranes was affected by both membrane phase state and the interference of QCT on membrane properties. Read More

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SARS-CoV-2-associated first episode of acute mania with psychotic features.

J Clin Neurosci 2021 May 1;87:29-31. Epub 2021 Mar 1.

Department of Psychiatry, Bakirkoy Prof Mazhar Osman Training and Research Hospital for Psychiatry, Neurology, and Neurosurgery, Istanbul, Turkey. Electronic address:

Despite neuropsychiatric outcomes of SARS-CoV-2 infection are now under close scrutiny, psychoneuroimmunological characteristics of COVID-19 and precise pathophysiology of neuropsychiatric manifestations of the infection are still obscure. Moreover, there still exists a shortfall in demonstrating specific clinical manifestations of the brain involvement of the virus. Here, we presented a 33-year-old female patient with COVID-19, reporting acute-onset paranoid delusions symptoms, insomnia and irritability. Read More

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