Search results for "MR"
showing 10 items of 3001 documents
Diastereoselective formation of homochiral flexible perylene bisimide cyclophanes and their hybrids with fullerenes†‡
2021
Cyclophanes of different ring sizes featuring perylene-3,4:9,10-tetracarboxylic acid bisimide (PBI) linked by flexible malonates were designed, synthesized, and investigated with respect to their structural, chemical and photo-physical properties. It is predominantly the number of PBIs and their geometric arrangement, which influence dramatically their properties. For example, two-PBI containing cyclophanes reveal physico-chemical characteristics that are governed by strong co-facial π–π interactions. This is in stark contrast to cyclophanes with either three or four PBIs. Key to co-facial π–π stackings are the flexible malonate linkers, which, in turn, set up the ways and means for diaster…
From small to medium and beyond: a pragmatic approach in predicting properties of Ne containing structures
2013
In this study, we outlined a pragmatic approach for structural studies leading to better understanding of polycarbon structures using 21Ne as a nuclear magnetic resonance (NMR) probe. 21Ne NMR parameters of a single neon atom and its dimer were predicted at the CCSD(T) level in combination with large basis sets. At a lower level of theory, an interaction of neon atom with 1,3-cyclopentadiene ring and with five- and six-membered rings in carbazole was studied using the restricted Hartree–Fock (RHF) and density functional theory (DFT) combined with smaller basis sets. The RHF and DFT modelling of neon interaction with nanosized objects were performed on cyclacenes and selected fullerenes.
Assessing High-Order Interdependencies Through Static O-Information Measures Computed on Resting State fMRI Intrinsic Component Networks
2022
Resting state brain networks have reached a strong popularity in recent scientific endeavors due to their feasibility to characterize the metabolic mechanisms at the basis of neural control when the brain is not engaged in any task. The evaluation of these states, consisting in complex physiological processes employing a large amount of energy, is carried out from diagnostic images acquired through resting-state functionalmagnetic resonance (RS-fMRI) on different populations of subjects. In the present study, RS-fMRI signals from the WU-MinnHCP 1200 Subjects Data Release of the Human Connectome Project were studied with the aim of investigating the high order organizational structure of the…
Isolation, purification and antibacterial effects of fusaproliferin produced by Fusariumsubglutinans in submerged culture.
2009
To evaluate the fusaproliferin (FUS) production, Fusariumsubglutinans ITEM 2404 was grown in a liquid medium of potato being this mycotoxin purified by high-performance liquid chromatography (HPLC) with a C18 semipreparative column using a mobile phase of acetonitrile/H(2)O using gradient conditions. The purity of the fusaproliferin was verified by analytical HPLC, ultraviolet absorbance measurements, LC/MS-MS, (1)H NMR spectroscopy. The isolated FUS was shown to be free of impurities and can be used as a standard for routine analysis. The pure fusaproliferin was utilized to study the biological activity on Escherichiacoli and Staphylococcusaureus. This study demostred that FUS not showed s…
Modeling 21Ne NMR parameters for carbon nanosystems
2013
The potential of nuclear magnetic resonance (NMR) technique in probing the structure of porous systems including carbon nanostructures filled with inert gases is analysed theoretically using accurate calculations of neon (21Ne) nuclear magnetic shieldings. The CBS estimates of 21Ne NMR parameters were performed for single atom, its dimer and neon interacting with acetylene, ethylene and 1,3-cyclopentadiene. Several levels of theory including restricted Hartree-Fock (RHF), Møller-Plesset perturbation theory to the second order (MP2), density functional theory (DFT) with van Voorhis and Scuseria's t-dependent gradient-corrected correlation functional (VSXC), coupled cluster with single and do…
Keypoint descriptor matching with context-based orientation estimation
2014
Abstract This paper presents a matching strategy to improve the discriminative power of histogram-based keypoint descriptors by constraining the range of allowable dominant orientations according to the context of the scene under observation. This can be done when the descriptor uses a circular grid and quantized orientation steps, by computing or providing a global reference orientation based on the feature matches. The proposed matching strategy is compared with the standard approaches used with the SIFT and GLOH descriptors and the recent rotation invariant MROGH and LIOP descriptors. A new evaluation protocol based on an approximated overlap error is presented to provide an effective an…
Comparison of 1.0 M gadobutrol and 0.5 M gadopentate dimeglumine-enhanced MRI in 471 patients with known or suspected renal lesions : results of a mu…
2008
The purpose of this phase III clinical trial was to compare two different extracellular contrast agents, 1.0 M gadobutrol and 0.5 M gadopentate dimeglumine, for magnetic resonance imaging (MRI) in patients with known or suspected focal renal lesions. Using a multicenter, single-blind, interindividual, randomized study design, both contrast agents were compared in a total of 471 patients regarding their diagnostic accuracy, sensitivity, and specificity to correctly classify focal lesions of the kidney. To test for noninferiority the diagnostic accuracy rates for both contrast agents were compared with CT results based on a blinded reading. The average diagnostic accuracy across the three bli…
Outcome of LR-3 and LR-4 observations without arterial phase hyperenhancement at Gd-EOB-DTPA-enhanced MRI follow-up
2020
Objective: The aim of this study was to retrospectively analyze the outcome of LR-3 and LR-4 without arterial phase hyperenhancement (APHE), and identify which features could predict LR-5 progression on serial Gd-EOB-DTPA-enhanced MRI follow-up. Methods: Forty-nine cirrhotic patients with 55 LR-3 and 19 LR-4 without APHE were evaluated. Observations were classified as decreased, stable or increased in category at follow-up. Observation size and LI-RADS major and ancillary features were evaluated. Results: Seventeen/fifty-five (31%) LR-3 and 8/19 (42%) LR-4 progressed to LR-5 at follow-up. Baseline LI-RADS major and ancillary features were not significantly different among LR-3 and LR-4. A d…
MR-imaging features of hepatocellular carcinoma capsule appearance in cirrhotic liver: comparison of gadoxetic acid and gadobenate dimeglumine.
2016
Purpose: The purpose of the study is to compare the MR-imaging features of hepatocellular carcinoma (HCC) capsule appearance on gadoxetic acid and gadobenate dimeglumine-enhanced MR imaging, using imaging-based presumptive diagnosis of HCC as the reference standard. Methods: Gadoxetic acid and gadobenate dimeglumine-enhanced MR imaging of 51 patients with 71 HCCs were retrospectively reviewed. Three readers graded in consensus, using a five-point scale, the presence (score 4–5) of capsule appearance on images obtained during T1-weighted GRE portal venous phase (PVP), 3-min phase, and hepatobiliary phase (HBP). The Fisher's exact test and the t student unpaired test were performed. Results: …
Gadoxetate disodium-enhanced magnetic resonance cholangiography for the noninvasive detection of an active bile duct leak after laparoscopic cholecys…
2010
Abstract We report a case of an endoscopically confirmed biliary leak of the common hepatic duct after laparoscopic cholecystectomy that was prospectively diagnosed on gadoxetate disodium-enhanced magnetic resonance cholangiography. Whereas dynamic contrast-enhanced magnetic resonance images during the early vascular phases helped to rule out the causes of possible complications such as seroma, hematoma, or abdominal abscess, delayed hepatobiliary phase imaging was crucial for unequivocal diagnosis and location of the biliary leak. The diagnosis prompted therapeutic endoscopic retrograde cholangiography whereby a polytetrafluoroethylene-covered nitinol stent graft was successfully placed to…