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https://www.readbyqxmd.com/read/29166135/application-of-diffusion-tensor-imaging-in-quantitatively-monitoring-chronic-constriction-injury-of-rabbit-sciatic-nerves-correlation-with-histological-and-functional-changes
#1
Wenjun Wu, Yanfeng Niu, Xiangquan Kong, Dingxi Liu, Xi Long, Shenglei Shu, Xiaoyun Su, Bing Wang, Xiaoming Liu, Yamei Ma, Lixia Wang
OBJECTIVE: To investigate the potential of diffusion tensor imaging (DTI) in quantitatively monitoring chronic constriction injuries (CCI) of sciatic nerves and to analyze the association of DTI parameters with nerve histology and limb function. METHODS: CCI was created on sciatic nerves in the right hind legs of 20 rabbits with the left as control. DTI parameters -- fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusivity (AD) and radial diffusivity (RD) -- and limb function were longitudinally evaluated...
November 22, 2017: British Journal of Radiology
https://www.readbyqxmd.com/read/29166113/statistical-mechanics-of-transport-processes-in-active-fluids-equations-of-hydrodynamics
#2
Katherine Klymko, Dibyendu Mandal, Kranthi K Mandadapu
The equations of hydrodynamics including mass, linear momentum, angular momentum, and energy are derived by coarse-graining the microscopic equations of motion for systems consisting of rotary dumbbells driven by internal torques. In deriving the balance of linear momentum, we find that the symmetry of the stress tensor is broken due to the presence of non-zero torques on individual particles. The broken symmetry of the stress tensor induces internal spin in the fluid and leads us to consider the balance of internal angular momentum in addition to the usual moment of momentum...
November 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29166053/towards-the-irving-kirkwood-limit-of-the-mechanical-stress-tensor
#3
E R Smith, D M Heyes, D Dini
The probability density functions (PDFs) of the local measure of pressure as a function of the sampling volume are computed for a model Lennard-Jones (LJ) fluid using the Method of Planes (MOP) and Volume Averaging (VA) techniques. This builds on the study of Heyes, Dini, and Smith [J. Chem. Phys. 145, 104504 (2016)] which only considered the VA method for larger subvolumes. The focus here is typically on much smaller subvolumes than considered previously, which tend to the Irving-Kirkwood limit where the pressure tensor is defined at a point...
June 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29166009/formation-of-spherical-aromatic-endohedral-metallic-fullerenes-evaluation-of-magnetic-properties-of-m-c28-m-ti-zr-and-hf-from-dft-calculations
#4
Alvaro Muñoz-Castro, R Bruce King
The small C28 cage has been shown experimentally to encapsulate titanium, zirconium, and hafnium (M), among other elements. Here, we explore computationally its magnetic response properties accounting for both global and local shielding tensors. Our results exhibit a continuous shielding region for M@C28 for an orientation-averaged applied field thereby differing from that observed for the hollow C28 structure. Moreover, under a specific orientation of the applied field a long-ranged shielding cone is obtained supporting the spherical aromatic behavior expected by the 2(N + 1)(2) Hirsch rule for M@C28, standing for its particular abundance...
November 22, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/29165452/conformational-analysis-of-spiro-epoxides-by-principal-component-analysis-of-molecular-dynamics-trajectories
#5
T Hrenar, I Primožič, D Fijan, M Majerić Elenkov
A new procedure for full conformational analyses comprising the statistical analysis of molecular dynamics trajectories was developed and applied. This method included a coordinate space for sampling using molecular dynamics simulations, reduction of dimensionality using tensor decomposition tools, determination of probability distributions in a reduced space, and finally the search for all of the strict extrema points of probability distributions. These extracted extrema points formed an initial guess for geometry optimization and clustering of conformers...
November 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29165048/psychoradiologic-utility-of-mr-imaging-for-diagnosis-of-attention-deficit-hyperactivity-disorder-a-radiomics-analysis
#6
Huaiqiang Sun, Ying Chen, Qiang Huang, Su Lui, Xiaoqi Huang, Yan Shi, Xin Xu, John A Sweeney, Qiyong Gong
Purpose To identify cerebral radiomic features related to diagnosis and subtyping of attention deficit hyperactivity disorder (ADHD) and to build and evaluate classification models for ADHD diagnosis and subtyping on the basis of the identified features. Materials and Methods A consecutive cohort of 83 age- and sex-matched children with newly diagnosed and never-treated ADHD (mean age 10.83 years ± 2.30; range, 7-14 years; 71 boys, 40 with ADHD-inattentive [ADHD-I] and 43 with ADHD-combined [ADHD-C, or inattentive and hyperactive]) and 87 healthy control subjects (mean age, 11...
November 22, 2017: Radiology
https://www.readbyqxmd.com/read/29164896/nuclear-magnetic-shielding-of-monoboranes-calculation-and-assessment-of-11b-nmr-chemical-shifts-in-planar-bx3-and-in-tetrahedral-bx4-systems
#7
Jan Machacek, Michael Buhl, Jindřich Fanfrlík, Drahomir Hnyk
11B NMR chemical shifts of tricoordinated BX3 and tetracoordinated BX4- compounds (X = H, CH3, F, Cl, Br, I, OH, SH, NH2, and CH=CH2) were computed and the shielding tensors were explored not only within the nonrelativistic GIAO approach but also by applying both relativistic ZORA computations including spin-orbit coupling as well as by employing scalar nonrelativistic ZORA computations (BP86 level of density functional theory). The contributions of the spin-orbit coupling to the overall shieldings are decisive for X = Br and I in both series...
November 22, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/29163337/disrupted-gamma-synchrony-after-mild-traumatic-brain-injury-and-its-correlation-with-white-matter-abnormality
#8
Chao Wang, Michelle E Costanzo, Paul E Rapp, David Darmon, Dominic E Nathan, Kylee Bashirelahi, Dzung L Pham, Michael J Roy, David O Keyser
Mild traumatic brain injury (mTBI) has been firmly associated with disrupted white matter integrity due to induced white matter damage and degeneration. However, comparatively less is known about the changes of the intrinsic functional connectivity mediated via neural synchronization in the brain after mTBI. Moreover, despite the presumed link between structural and functional connectivity, no existing studies in mTBI have demonstrated clear association between the structural abnormality of white matter axons and the disruption of neural synchronization...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/29163330/white-matter-changes-in-hiv-women-with-a-history-of-cocaine-dependence
#9
Kathryn-Mary Wakim, Ciara J Molloy, Ryan P Bell, Lars A Ross, John J Foxe
Cocaine use is associated with the transmission of human immunodeficiency (HIV) virus through risky sexual behavior. In HIV+ individuals, cocaine use is linked with poor health outcomes, including HIV-medication non-adherence and faster disease progression. Both HIV and cocaine dependence are associated with reduced integrity of cerebral white matter (WM), but the effects of HIV during cocaine abstinence have not yet been explored. We used diffusion tensor imaging (DTI) to understand the effect of combined HIV+ serostatus and former cocaine dependence on cerebral WM integrity...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/29163108/alterations-in-white-matter-integrity-in-young-adults-with-smartphone-dependence
#10
Yuanming Hu, Xiaojing Long, Hanqing Lyu, Yangyang Zhou, Jianxiang Chen
Smartphone dependence (SPD) is increasingly regarded as a psychological problem, however, the underlying neural substrates of SPD is still not clear. High resolution magnetic resonance imaging provides a useful tool to help understand and manage the disorder. In this study, a tract-based spatial statistics (TBSS) analysis on diffusion tensor imaging (DTI) was used to measure white matter integrity in young adults with SPD. A total of 49 subjects were recruited and categorized into SPD and control group based on their clinical behavioral tests...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/29162178/childhood-maltreatment-moderates-the-effect-of-combat-exposure-on-cingulum-structural-integrity
#11
Layla Banihashemi, Meredith L Wallace, Lei K Sheu, Michael C Lee, Peter J Gianaros, Robert P Mackenzie, Salvatore P Insana, Anne Germain, Ryan J Herringa
Limbic white matter pathways link emotion, cognition, and behavior and are potentially malleable to the influences of traumatic events throughout development. However, the impact of interactions between childhood and later life trauma on limbic white matter pathways has yet to be examined. Here, we examined whether childhood maltreatment moderated the effect of combat exposure on diffusion tensor imaging measures within a sample of military veterans (N = 28). We examined five limbic tracts of interest: two components of the cingulum (cingulum, cingulate gyrus, and cingulum hippocampus [CGH]), the uncinate fasciculus, the fornix/stria terminalis, and the anterior limb of the internal capsule...
December 2017: Development and Psychopathology
https://www.readbyqxmd.com/read/29162009/rank-optimized-logistic-matrix-regression-toward-improved-matrix-data-classification
#12
Jianguang Zhang, Jianmin Jiang
While existing logistic regression suffers from overfitting and often fails in considering structural information, we propose a novel matrix-based logistic regression to overcome the weakness. In the proposed method, 2D matrices are directly used to learn two groups of parameter vectors along each dimension without vectorization, which allows the proposed method to fully exploit the underlying structural information embedded inside the 2D matrices. Further, we add a joint [Formula: see text]-norm on two parameter matrices, which are organized by aligning each group of parameter vectors in columns...
November 21, 2017: Neural Computation
https://www.readbyqxmd.com/read/29161620/in-situ-elastic-strain-mapping-during-micromechanical-testing-using-ebsd
#13
Mark J McLean, William A Osborn
Compared to more commonly used strain measurement techniques, electron backscatter diffraction (EBSD) offers improved spatial resolution and measurement sensitivity. Additionally, EBSD can provide the full deformation tensor, whereas other techniques, such as digital image correlation (DIC), are limited to only in-plane strains and rotations. In this work, EBSD was used to measure strains and rotations in-situ during testing of a single-crystal silicon micromechanical test specimen. The theta-like specimen geometry was chosen due to the complex and spatially-varying strain states that exist in the circular frame of the sample during testing, as well as the nominally uniform strains in the central web...
November 14, 2017: Ultramicroscopy
https://www.readbyqxmd.com/read/29161349/relation-of-retinal-and-serum-lutein-and-zeaxanthin-to-white-matter-integrity-in-older-adults-a-diffusion-tensor-imaging-study
#14
Catherine M Mewborn, Douglas P Terry, Lisa M Renzi-Hammond, Billy R Hammond, L Stephen Miller
Objective: Lutein (L) and zeaxanthin (Z) are phytonutrients that accumulate in human brain tissue and positively impact cognition. Given their antioxidant and anti-inflammatory properties and their role in stabilizing cell membranes, L&Z may relate to measures of white matter integrity (WMI). Method: The current study tested the relation of retinal (macular pigment optical density/MPOD) and blood serum concentrations of L&Z to WMI in community-dwelling older adults (n = 54) using diffusion tensor imaging (DTI)...
November 17, 2017: Archives of Clinical Neuropsychology: the Official Journal of the National Academy of Neuropsychologists
https://www.readbyqxmd.com/read/29159816/on-the-isotropy-of-induced-multipole-moments-in-heavy-ion-complexes
#15
Michael Trumm
Polarization effects have been proven to play an important role in the theoretical description of chemical processes. With this respect, we report ab initio calculations describing multiconfigurational and relativistic effects as well as electron correlation to determine dipole- and quadrupole polarizabilities for all trivalent actinide and lanthanide ions. The results are used in an iterative point-multipole model to compute polarization interaction for different metal compounds. Significant differences between the usage of isotropic polarizabilities for the coordinating ligands compared to the full tensor representation is found...
November 20, 2017: Journal of Computational Chemistry
https://www.readbyqxmd.com/read/29159467/the-use-of-multiparametric-quantitative-magnetic-resonance-imaging-for-evaluating-visually-assigned-lesion-groups-in-patients-with-multiple-sclerosis
#16
Christian Thaler, Tobias D Faizy, Jan Sedlacik, Maxim Bester, Jan-Patrick Stellmann, Christoph Heesen, Jens Fiehler, Susanne Siemonsen
In multiple sclerosis (MS), inflammatory lesions present a broad spectrum of histopathologic processes. For a better discrimination, lesions are visually defined into different lesion groups according to their appearance on conventional magnetic resonance imaging (MRI). The aim of this study was to investigate the properties of different MS lesion groups using multiparametric quantitative MRI. 35 patients diagnosed with relapsing-remitting MS received 3 Tesla MRI including magnetization-prepared 2 rapid acquisition gradient echo, diffusion tensor imaging and magnetization transfer imaging...
November 20, 2017: Journal of Neurology
https://www.readbyqxmd.com/read/29159052/subcortical-grey-matter-changes-in-juvenile-myoclonic-epilepsy
#17
Ji Hyun Kim, Jung Bin Kim, Sang-Il Suh, Dong Wook Kim
Recent neuroimaging studies have provided converging evidence of structural and functional abnormalities of the thalamus in patients with juvenile myoclonic epilepsy (JME). There has also been limited evidence indicating involvement of the subcortical grey matter structures other than thalamus in JME, but with inconsistent findings across the studies. In the present study, we combined volumetric MRI and diffusion tensor imaging analyses to investigate macrostructural and microstructural alterations of the subcortical grey matter in 64 JME patients compared to 58 matched control subjects...
2018: NeuroImage: Clinical
https://www.readbyqxmd.com/read/29159046/imaging-of-glia-activation-in-people-with-primary-lateral-sclerosis
#18
Sabrina Paganoni, Mohamad J Alshikho, Nicole R Zürcher, Paul Cernasov, Suma Babu, Marco L Loggia, James Chan, Daniel B Chonde, David Izquierdo Garcia, Ciprian Catana, Caterina Mainero, Bruce R Rosen, Merit E Cudkowicz, Jacob M Hooker, Nazem Atassi
Background: Glia activation is thought to contribute to neuronal damage in several neurodegenerative diseases based on preclinical and human post-mortem studies, but its role in primary lateral sclerosis (PLS) is unknown. Objectives: To localize and measure glia activation in people with PLS compared to healthy controls (HC). Methods: Ten participants with PLS and ten age-matched HCs underwent simultaneous magnetic resonance (MR) and proton emission tomography (PET)...
2018: NeuroImage: Clinical
https://www.readbyqxmd.com/read/29159043/neuroimaging-and-other-modalities-to-assess-alzheimer-s-disease-in-down-syndrome
#19
REVIEW
Natalie Neale, Concepcion Padilla, Luciana Mascarenhas Fonseca, Tony Holland, Shahid Zaman
People with Down syndrome (DS) develop Alzheimer's disease (AD) at higher rates and a younger age of onset compared to the general population. As the average lifespan of people with DS is increasing, AD is becoming an important health concern in this group. Neuroimaging is becoming an increasingly useful tool in understanding the pathogenesis of dementia development in relation to clinical symptoms. Furthermore, neuroimaging has the potential to play a role in AD diagnosis and monitoring of therapeutics. This review describes major recent findings from in vivo neuroimaging studies analysing DS and AD via ligand-based positron emission tomography (PET), [18F] fluorodeoxyglucose (FDG)-PET, structural magnetic resonance imaging (sMRI), and diffusion tensor imaging (DTI)...
2018: NeuroImage: Clinical
https://www.readbyqxmd.com/read/29159041/white-matter-alterations-and-their-associations-with-motor-function-in-young-adults-born-preterm-with-very-low-birth-weight
#20
Ingrid Marie Husby Hollund, Alexander Olsen, Jon Skranes, Ann-Mari Brubakk, Asta K Håberg, Live Eikenes, Kari Anne I Evensen
Very low birth weight (VLBW: ≤ 1500 g) individuals have an increased risk of white matter alterations and neurodevelopmental problems, including fine and gross motor problems. In this hospital-based follow-up study, the main aim was to examine white matter microstructure and its relationship to fine and gross motor function in 31 VLBW young adults without cerebral palsy compared with 31 term-born controls, at mean age 22.6 ± 0.7 years. The participants were examined with tests of fine and gross motor function (Trail Making Test-5: TMT-5, Grooved Pegboard, Triangle from Movement Assessment Battery for Children-2: MABC-2 and High-level Mobility Assessment Tool: HiMAT) and diffusion tensor imaging (DTI)...
2018: NeuroImage: Clinical
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