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proton density

Risa Matsubara, Yoshinobu Yanagi, Kazuhiro Oki, Miki Hisatomi, Karina Cp Santos, Babatunde O Bamgbose, Mariko Fujita, Shunsuke Okada, Shogo Minagi, Junichi Asaumi
OBJECTIVES: To investigate the correlations among various temporomandibular joint (TMJ) findings on MRI and the relationships between MRI findings and symptoms. METHODS: 425 patients (850 TMJs) with temporomandibular joint disorders (TMDs) who underwent MRI were enrolled. Oblique sagittal proton density-weighted and T 2 weighted images in open- and closed-mouth positions were evaluated. MRI findings included disc configuration, disc position, condylar morphology, bone marrow pattern, and joint effusion...
February 16, 2018: Dento Maxillo Facial Radiology
Junmin Liu, Spencer Christiansen, Maria Drangova
Multi-echo gradient echo (mGRE) sequences have been widely adapted in clinical and scientific practice for different purposes to their capability of performing Dixon MRI, generating multi-contrast images and extracting multi-parametric maps. This work aims to extend mGRE-based techniques for imaging whole head, where further technical developments are required due to the co-existence of fat and large B0 inhomogeneity in regions such as the skull base and neck. Specifically, bipolar mGRE data were acquired with a single sequence that contains both a short echo-spacing (ΔTE) echo train to capture water-fat and B0 phase shifts (for proton density fat-fraction (FF) and B0 mapping) and a longer ΔTE echo train (and long echo times) to capture subtle susceptibility variations and R2* information...
February 12, 2018: NeuroImage
Fahed Alsanea, Francois Therriault-Proulx, Gabriel Sawakuchi, Sam Beddar
PURPOSE: Currently, no detectors are capable of simultaneously measuring dose and linear energy transfer (LET) in real time. In this study, we evaluated the feasibility of exploiting the difference in the response of various organic plastic scintillation detectors to measure LET and dose in therapeutic proton beams. The hypothesis behind this work was that the ratio of the responses of different scintillators exposed to the same proton beam can be used to obtain a LET-vs-ratio calibration curve that can then be used to infer LET under any other measurement conditions...
February 15, 2018: Medical Physics
Abha Bharti, Shaneeth Muliankeezhu, Gouri Cheruvally
Pt-TiO2 nanocomposite catalysts in different Pt:Ti atomic ratios (1:1, 2:1 and 3:1) were synthesized in acidic (pH < 3) and basic (pH >10) medium for oxygen reduction reaction of proton exchange membrane fuel cells. The pH of synthesis medium significantly affected both physicochemical and catalytic properties of Pt-TiO2. Pt-TiO2 prepared in acidic medium exhibited smaller crystallite size, higher specific surface area and more non-stoichiometric titania with higher electrical conductivity as compared to that prepared in basic medium...
April 1, 2018: Journal of Nanoscience and Nanotechnology
S Thangarasu, S Athimoolam, S Asath Bahadur, A Manikandan
The proton transfer salts of 2-aminopyrimidine with nitric acid (2APNO) and oxalic acid (2APOX) were synthesized and crystallized successfully by solvent evaporation solution growth technique. The crystal packing is stabilized through intricate three dimensional hydrogen bonded network. Both, the molecular structures were optimized with Density Functional Theory (DFT) using B3LYP function and Hartree-Fock method with a 6-311++G(d,p) basis set. Optimized molecular parameters between the methods were compared for the cation showing appreciable agreement...
April 1, 2018: Journal of Nanoscience and Nanotechnology
Seung Hyeon Kim, Juhoon Lee, Gabriela I Vargas-Zúñiga, Vincent M Lynch, Benjamin P Hay, Jonathan L Sessler, Sung Kuk Kim
The binding interactions between the azide anion (N3-) and the strapped calix[4]pyrroles 2 and 3 bearing auxiliary hydrogen bonding donors on the bridging moieties, as well as of normal calix[4]pyrrole 1, were investigated via 1H NMR spectroscopic and ITC (isothermal titration calorimetry) analyses. The resulting data revealed that receptors 2 and 3 have significantly higher affinities for the azide anion in organic media as compared with the unfunctionalized calix[4]pyrrole 1 and other azide receptors reported to date...
February 14, 2018: Journal of Organic Chemistry
Miquel Navarro, Christene Smith, Mo Li, Stefan Bernhard, Martin Albrecht
The synthetic versatility of PYA ligands has been exploited to prepare and evaluate a diverging series of iridium complexes containing C,N-bidentate chelating aryl-PYA ligands for water oxidation catalysis. The phenyl-PYA lead structure was modified (i) electronically through introduction of one, two, or three electron-donating methoxy substituents on the aryl ring, (ii) by incorporating long aliphatic chains to the pyridyl fragment of the PYA unit, and (iii) by altering the PYA positions from para-PYA to its ortho- and meta-isomers...
February 14, 2018: Chemistry: a European Journal
Chunyu Ru, Zhenhua Li, Chengji Zhao, Yuting Duan, Zhuang Zhuang, Fanzhe Bu, Hui Na
Novel side-chain-type sulfonated poly (arylene ether ketone) (SNF-PAEK) containing naphthalene and fluorine moieties on the main chain was prepared in this work, and a new amino-sulfo-bifunctionalized metal-organic framework (MNS, short for MIL-101-NH2-SO3H) was synthesized via a hydrothermal technology and post-modification. Then MNS was incorporated into SNF-PAEK matrix as an inorganic nano-filler to prepare a series of organic-inorganic hybrid membranes (MNS@SNF-PAEK-XX). The mechanical property, methanol resistance, electrochemistry and other properties of MNS@SNF-PAEK-XX hybrid membranes were detailed characterized...
February 14, 2018: ACS Applied Materials & Interfaces
M Castellà-Ventura, A Moissette, E Kassab
The confinement effects of a zeolite framework on the adsorption of a bidentate 4,4'-bipyridine (44BPY) ligand on the straight channel of H-ZSM-5 have been investigated by density functional theory calculations using B3LYP, B3LYP-D3, M06-2X, M06-2X-D3 functionals, and the MP2 method with two basis sets 6-31+G* and 6-31++G(2d,2p). The straight channel is simulated by a realistic cluster model of 32 tetrahedra (T), having two aluminum atoms located in the straight and intersection regions, respectively. The potential energy surface of the double proton transfer reaction from the Brønsted acid sites of H-ZSM-5 to 44BPY is characterized by three minima corresponding to two monodentate ion pair complexes 44BPYH+/32T- and one bidentate ion pair complex 44BPYH22+/32T2- formed consecutively via two distinct pathways...
February 13, 2018: Physical Chemistry Chemical Physics: PCCP
Tatsuya Hayashi, Kei Fukuzawa, Hidekazu Yamazaki, Takashi Konno, Tosiaki Miyati, Jun'ichi Kotoku, Hiroshi Oba, Hiroshi Kondo, Keiko Toyoda, Satoshi Saitoh
PURPOSE: To evaluate the reproducibility of proton density fat fraction (PDFF) and T2* in a fat-water phantom on three different 3 T MRI systems using 6-point DIXON methods. METHODS: A phantom which included varying fat volume percentages (true fat fraction [FF]) was scanned by three 3 T MR machines, and PDFF and T2* were measured. RESULTS: The mean difference between true FF and PDFF was small in all vendors (-2.11% to 0.41%). However, the difference ratio for T2* values was large among vendors (1...
February 2, 2018: Clinical Imaging
T Tada, T Kumada, H Toyoda, Y Sone, K Takeshima, S Ogawa, T Goto, A Wakahata, M Nakashima, M Nakamuta, J Tanaka
BACKGROUND: Whether direct-acting anti-viral therapy can reduce liver fibrosis and steatosis in patients with chronic hepatitis C virus (HCV) infection is unclear. AIMS: To evaluate changes in liver stiffness and steatosis in patients with HCV who received direct-acting anti-viral therapy and achieved sustained virological response (SVR). METHODS: A total of 198 patients infected with HCV genotype 1 or 2 who achieved SVR after direct-acting anti-viral therapy were analysed...
February 9, 2018: Alimentary Pharmacology & Therapeutics
M Savastano, C Bazzicalupi, C García-Gallarín, C Giorgi, M D López de la Torre, F Pichierri, A Bianchi, M Melguizo
The formation of halide and hydroxide anion complexes with two ligands L1 (3,6-bis(morpholin-4-ylmethyl)-1,2,4,5-tetrazine) and L2 (3,6-bis(morpholin-4-ylethyl)-1,2,4,5-tetrazine) was studied in aqueous solution, by means of potentiometric and ITC procedures. In the solid state, HF2-, Cl- and Br- complexes of H2L22+ were analysed by single crystal XRD measurements. Further information on the latter was obtained with the use of density functional theory (DFT) calculations in combination with the polarizable continuum model (PCM)...
February 9, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Fumihito Yoshii, Hitoshi Tomiyasu, Ryo Watanabe, Masafuchi Ryo
Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant spinocerebellar degeneration, associated with extended repeats of the trinucleotide CAG in the ATXN2 gene on the long arm of chromosome 12. Magnetic resonance imaging (MRI) of SCA2 showed significant atrophies of the brainstem, middle cerebellar peduncles, and cerebellum. We report two genetically proven SCA2 patients who showed hypertrophy of the inferior olivary nuclei on proton density- and T2-weighted MRI. This pattern has never been reported in patients with SCA1, SCA3, or SCA6, and may make it possible to differentiate SCA2 from other hereditary spinocerebellar ataxias...
September 2017: Case Reports in Neurology
N T Henthorn, J W Warmenhoven, M Sotiropoulos, R I Mackay, N F Kirkby, K J Kirkby, M J Merchant
This work uses Monte Carlo simulations to investigate the dependence of residual and misrepaired double strand breaks (DSBs) at 24 hours on the initial damage pattern created during ion therapy. We present results from a nanometric DNA damage simulation coupled to a mechanistic model of Non-Homologous End Joining, capable of predicting the position, complexity, and repair of DSBs. The initial damage pattern is scored by calculating the average number of DSBs within 70 nm from every DSB. We show that this local DSB density, referred to as the cluster density, can linearly predict misrepair regardless of ion species...
February 8, 2018: Scientific Reports
Dahui Wang, Yinren Shou, Pengjie Wang, Jianbo Liu, Chengcai Li, Zheng Gong, Ronghao Hu, Wenjun Ma, Xueqing Yan
We report a simulation study on proton acceleration driven by ultraintense laser pulses with normal contrast (107-109) containing nanosecond plateau amplified spontaneous emission (ASE). It's found in hydrodynamic simulations that if the thickness of the targets lies in the range of hundreds nanometer matching the intensity and duration of ASE, the ablation pressure would push the whole target in the forward direction with speed exceeding the expansion velocity of plasma, resulting in a plasma density profile with a long extension at the target front and a sharp gradient at the target rear...
February 7, 2018: Scientific Reports
Janne West, Thobias Romu, Sofia Thorell, Hanna Lindblom, Emilia Berin, Anna-Clara Spetz Holm, Lotta Lindh Åstrand, Anette Karlsson, Magnus Borga, Mats Hammar, Olof Dahlqvist Leinhard
OBJECTIVES: To determine precision of magnetic resonance imaging (MRI) based fat and muscle quantification in a group of postmenopausal women. Furthermore, to extend the method to individual muscles relevant to upper-body exercise. MATERIALS AND METHODS: This was a sub-study to a randomized control trial investigating effects of resistance training to decrease hot flushes in postmenopausal women. Thirty-six women were included, mean age 56 ± 6 years. Each subject was scanned twice with a 3...
2018: PloS One
Yang Wang, Zhong-Ying Ma, De-Long Zhang, Jia-Li Deng, Xiong Chen, Cheng-Zhi Xie, Xin Qiao, Qing-Zhong Li, Jing-Yuan Xu
A new aluminum ion fluorescent probe (4-(diethylamino)-2-hydroxybenzylidene)isoquinoline-1-carbohydrazide (HL1) has been conveniently synthesized and characterized. HL1 exhibited a highly selective and pronounced enhancement for Al3+ in the fluorescence emission over other common cations by forming a 2:1 complex, with a recognition mechanism based on excited-state intramolecular proton transfer (ESIPT) and intramolecular charge transfer (ICT). The strong fluorescent emission can be observed even at ppm level concentration of the probe in the presence of Al3+ with 41 fold intensity enhancement at 545 nm...
January 29, 2018: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Gonzalez Torres Maria Jose, Henniger Jürgen
In order to expand the Monte Carlo transport program AMOS to particle therapy applications, the ion module is being developed in the radiation physics group (ASP) at the TU Dresden. This module simulates the three main interactions of ions in matter for the therapy energy range: elastic scattering, inelastic collisions and nuclear reactions. The simulation of the elastic scattering is based on the Binary Collision Approximation and the inelastic collisions on the Bethe-Bloch theory. The nuclear reactions, which are the focus of the module, are implemented according to a probabilistic-based model developed in the group...
January 2018: Physica Medica: PM
Igor Shamovsky, Graham Belfield, Richard Lewis, Frank Narjes, Lena Ripa, Christian Tyrchan, Lisa Öberg, Peter Sjö
Nitric oxide (NO·) is a messenger molecule with diverse physiological roles including host defense, neurotransmission and vascular function. The synthesis of NO· from l-arginine is catalyzed by NO-synthases and occurs in two steps through the intermediary Nω-hydroxy-l-arginine (NHA). In both steps the P450-like reaction cycle is coupled with the redox cycle of the cofactor tetrahydrobiopterin (H4B). The mechanism of the second step is studied by Density Functional Theory calculations to ascertain the canonical sequence of proton and electron transfer (PT and ET) events...
January 10, 2018: Journal of Inorganic Biochemistry
Bo Jiang, Haihong He, Yijie Liu, Yizhen Tang, Siyi Luo, Zhaohui Wang
This study reports that the redox reactions between weak electron donors and Cr(VI) can be significantly accelerated by many environmentally occurring or industrially produced polycarboxylates (PolyCAs). The results demonstrate that oxalic acid (OA) can act as a redox mediator to accelerate the reduction of Cr(VI) by As(III) in pH range of 2.0-5.0, as well as a reductant donating electron for Cr(VI) reduction at pH < 4.0. Density functional theory calculation results indicate that the coordination of OA with Cr(VI) can remarkably enhance the reactivity of the CrO bond in HCrO4- toward oxygen atom transfer or the protonation of oxo groups during Cr(VI) reduction...
January 12, 2018: Chemosphere
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