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Magnetization transfer

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https://www.readbyqxmd.com/read/28548530/strain-induced-gauge-field-and-landau-levels-in-acoustic-structures
#1
Zhaoju Yang, Fei Gao, Yahui Yang, Baile Zhang
The emerging field of topological acoustics that explores novel gauge-field-related phenomena for sound has drawn attention in recent years. However, previous approaches constructing a synthetic gauge field for sound predominantly relied on a periodic system, being unable to form a uniform effective magnetic field, thus lacking access to some typical magnetic-induced quantum phenomena such as Landau energy quantization. Here we introduce strain engineering, previously developed in graphene electronics and later transferred to photonics, into a two-dimensional acoustic structure in order to form a uniform effective magnetic field for airborne acoustic wave propagation...
May 12, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28547862/mri-evaluation-of-regional-and-longitudinal-changes-in-z-spectra-of-injured-spinal-cord-of-monkeys
#2
Feng Wang, Zhongliang Zu, Ruiqi Wu, Tung-Lin Wu, John C Gore, Li Min Chen
PURPOSE: In principle, MR methods that exploit magnetization transfer (MT) may be used to quantify changes in the molecular composition of tissues after injury. The ability to track such changes in injured spinal cord may allow more precise assessment of the state of neural tissues. METHODS: Z-Spectra were obtained from the cervical spinal cord before and after a unilateral dorsal column lesion in monkeys at 9.4T. The amplitudes of chemical exchange saturation transfer (CEST) and nuclear Overhauser enhancement (NOE) effects from multiple proton pools, along with nonspecific semisolid MT effects from immobile macromolecules, were quantified using a five-peak Lorenzian fitting of each Z-spectrum...
May 25, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28547740/biliary-duodenal-anastomosis-using-magnetic-compression-following-massive-resection-of-small-intestine-due-to-strangulated-ileus-after-living-donor-liver-transplantation-a-case-report
#3
Ryusuke Saito, Hiroyuki Tahara, Seiichi Shimizu, Masahiro Ohira, Kentaro Ide, Kohei Ishiyama, Tsuyoshi Kobayashi, Hideki Ohdan
BACKGROUND: Despite the improvements of surgical techniques and postoperative management of patients with liver transplantation, biliary complications are one of the most common and important adverse events. We present a first case of choledochoduodenostomy using magnetic compression following a massive resection of the small intestine due to strangulated ileus after living donor liver transplantation. CASE PRESENTATION: The 54-year-old female patient had end-stage liver disease, secondary to liver cirrhosis, due to primary sclerosing cholangitis with ulcerative colitis...
December 2017: Surgical Case Reports
https://www.readbyqxmd.com/read/28546556/smelting-reduction-and-kinetics-analysis-of-magnetic-iron-in-copper-slag-using-waste-cooking-oil
#4
Bo Li, Xubin Wang, Hua Wang, Yonggang Wei, Jianhang Hu
To improve the recovery of copper, the viscosity of copper molten slag is decreased by the reduction of magnetic iron, which, in turn, accelerates the settling and separation of copper droplets from the slag. A new technology is proposed in which waste cooking oil is used as a reductant to reduce magnetic iron in the copper smelting slag and consequently reduce carbon emissions in the copper smelting process. A kinetic model of the reduction of magnetic iron in copper slag by waste cooking oil was built using experimental data, and the accuracy of the model was verified...
May 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28544208/ultra-high-field-magnetic-resonance-spectroscopy-in-non-alcoholic-fatty-liver-disease-novel-mechanistic-and-diagnostic-insights-of-energy-metabolism-in-non-alcoholic-steatohepatitis-and-advanced-fibrosis
#5
Stefan Traussnigg, Christian Kienbacher, Martin Gajdošík, Ladislav Valkovič, Emina Halilbasic, Judith Stift, Christian Rechling, Harald Hofer, Petra Steindl-Munda, Peter Ferenci, Fritz Wrba, Siegfried Trattnig, Martin Krššák, Michael Trauner
BACKGROUND & AIMS: With the rising prevalence of non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) non-invasive tools obtaining pathomechanistic insights to improve risk stratification are urgently needed. We therefore explored high- and ultra-high-field magnetic resonance spectroscopy (MRS) to obtain novel mechanistic and diagnostic insights into alterations of hepatic lipid, cell membrane and energy metabolism across the spectrum of NAFLD. METHODS: MRS and liver biopsy were performed in 30 NAFLD patients with NAFL (n=8) or NASH (n=22)...
April 24, 2017: Liver International: Official Journal of the International Association for the Study of the Liver
https://www.readbyqxmd.com/read/28544159/simultaneous-measurement-of-t1-b1-and-pharmacokinetic-model-parameters-using-active-contrast-encoding-ace-mri
#6
Jin Zhang, Kerryanne Winters, Olivier Reynaud, Sungheon Gene Kim
The aim of this study was to assess the feasibility of combining dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) with the measurement of the radiofrequency (RF) transmit field B1 and pre-contrast longitudinal relaxation time T10 . A novel approach has been proposed to simultaneously estimate B1 and T10 from a modified DCE-MRI scan that actively encodes the washout phase of the curve with different amounts of T1 and B1 weighting using multiple flip angles and repetition times, hence referred to as active contrast encoding (ACE)-MRI...
May 22, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28544035/chemical-exchange-sensitive-mri-of-amide-amine-and-noe-at-9-4%C3%A2-t-versus-15-2%C3%A2-t
#7
Julius Juhyun Chung, Wonmin Choi, Tao Jin, Jung Hee Lee, Seong-Gi Kim
Chemical exchange (CE)-sensitive MRI benefits greatly from stronger magnetic fields; however, field effects on CE-sensitive imaging have not yet been studied well in vivo. We have compared CE-sensitive Z-spectra and maps obtained at the fields of 9.4 T and 15.2 T in phantoms and rats with off-resonance chemical-exchange-sensitive spin lock (CESL), which is similar to conventional chemical exchange saturation transfer. At higher fields, the background peak at water resonance has less spread and the exchange rate relative to chemical shift decreases, thus CESL intensity is dependent on B0 ...
May 22, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28543885/dce-mri-prediction-of-survival-time-for-patients-with-glioblastoma-multiforme-using-an-adaptive-neuro-fuzzy-based-model-and-nested-model-selection-technique
#8
Azimeh N V Dehkordi, Alireza Kamali-Asl, Ning Wen, Tom Mikkelsen, Indrin J Chetty, Hassan Bagher-Ebadian
This pilot study investigates the construction of an Adaptive Neuro-Fuzzy Inference System (ANFIS) for the prediction of the survival time of patients with glioblastoma multiforme (GBM). ANFIS is trained by the pharmacokinetic (PK) parameters estimated by the model selection (MS) technique in dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) data analysis, and patient age. DCE-MRI investigations of 33 treatment-naïve patients with GBM were studied. Using the modified Tofts model and MS technique, the following physiologically nested models were constructed: Model 1, no vascular leakage (normal tissue); Model 2, leakage without efflux; Model 3, leakage with bidirectional exchange (influx and efflux)...
May 25, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28543840/imaging-of-nuclear-overhauser-enhancement-at-7-and-3%C3%A2-t
#9
Yuanyu Shen, Gang Xiao, Zhiwei Shen, Xiaolei Zhang, Xiangyong Tang, Wei Hu, Zhiyan Zhang, Jitian Guan, Renhua Wu
Nuclear Overhauser enhancement (NOE) is a type of magnetization transfer using cross-relaxation. It originates from mobile macromolecules, which may have relevance to the evaluation of tumor features. We studied the value of NOE imaging at 7 and 3 T and suggest a utility for diagnosing human brain tumors. Two types of protein solution at different concentrations and pH values, and six normal Sprague Dawley (SD) rats, were used to detect NOE signal with a 7 T scanner. Then, six healthy volunteers and 11 patients with brain tumors (six gliomas and five meningiomas) were included at 3 T...
May 24, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28542095/magnetization-transfer-magnetic-resonance-imaging-noninvasively-detects-renal-fibrosis-in-swine-atherosclerotic-renal-artery-stenosis-at-3-0-t
#10
Kai Jiang, Christopher M Ferguson, John R Woollard, Xiangyang Zhu, Lilach O Lerman
OBJECTIVES: Renal fibrosis is a useful biomarker for diagnosis and evaluation of therapeutic interventions of renal diseases but often requires invasive testing. Magnetization transfer magnetic resonance imaging (MT-MRI), which evaluates the presence of macromolecules, offers a noninvasive tool to probe renal fibrosis in murine renal artery stenosis (RAS) at 16.4 T. In this study, we aimed to identify appropriate imaging parameters for collagen detection at 3.0 T MRI and to test the utility of MT-MRI in measuring renal fibrosis in a swine model of atherosclerotic RAS (ARAS)...
May 24, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28539602/effect-of-excitation-power-on-voltage-induced-local-magnetization-dynamics-in-an-ultrathin-cofeb-film
#11
Bivas Rana, Yasuhiro Fukuma, Katsuya Miura, Hiromasa Takahashi, YoshiChika Otani
Voltage or electric field induced magnetization dynamics promises low power spintronics devices. For successful operation of some spintronics devices such as magnetic oscillators and magnetization switching devices a clear understanding of nonlinear magnetization dynamics is required. Here, we report a detailed experimental and micromagnetic simulation study about the effect of excitation power on voltage induced local magnetization dynamics in an ultrathin CoFeB film. Experimental results show that the resonance line-width and frequency remains constant, whereas cone angle of the magnetization precession increases linearly with square-root of excitation power below threshold value, known as linear excitation regime...
May 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28538856/-an-adolescent-with-lumbosacral-instability-due-to-the-presence-of-a-hydatid-cyst-a-case-report
#12
Miguel Vizcarra, Mijaíl Mujica, Vladimir Sánchez, Paul Méndez
Hydatidosis, caused by Echinococcus granulosus, affects the spinal column in 0.5-2% of all cases, with the sacral column being a rare location typically observed only in adults. The case is reported of a 14-year-old boy from Juliaca (Puno, Peru) who presented with chronic lower back pain and cauda equina syndrome. He was initially attended to in Juliaca, and then transferred to the Hospital Edgardo Rebagliati Martins (Lima, Peru) with a diagnosis of sacral tumor. In magnetic resonance imaging, a multicystic tumor was seen with L5 and S1 lysis and instability...
January 2017: Revista Peruana de Medicina Experimental y Salud Pública
https://www.readbyqxmd.com/read/28535412/selective-separation-and-determination-of-glucocorticoids-in-cosmetics-using-dual-template-magnetic-molecularly-imprinted-polymers-and-hplc
#13
Min Liu, Xiaoyan Li, Junjie Li, Zongyuan Wu, Fang Wang, Li Liu, Xuecai Tan, Fuhou Lei
Molecularly imprinting polymers (MIPs) are typically prepared using a single template molecule, which allows selective separation and enrichment of only one target analyte. It is not suitable for determination of complex real samples containing multiple analytes. In order to expand the practical application of imprinted polymers, novel dual-template magnetic molecularly imprinted polymers (MMIPs) were synthesized by surface polymerization using hydrocortisone and dexamethasone as the dual-template molecules in this study...
May 17, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28532968/off-loading-wheelchair-cushion-provides-best-case-reduction-in-tissue-deformation-as-indicated-by-mri
#14
Evan Call, Thomas Hetzel, Chad McLean, Joshua N Burton, Craig Oberg
Off-loading or the Orthotic approach to wheelchair seating has been used successfully to provide seating that optimizes tissue protection at the ischial tuberosities (ITs), sacrum and greater trochanters. Recent publications indicate the significance of preventing tissue compression to reduce ulcer formation. Comparative Magnetic Resonance Imaging (MRI) of individuals seated on two cushion types provides direct evidence of tissue unloading resulting in the reduction in tissue compression. Measurement of tissue compression in MRI images provides the cumulative impact of compression and shear resulting in ultimate tissue thickness documented here...
May 18, 2017: Journal of Tissue Viability
https://www.readbyqxmd.com/read/28532118/facile-synthesis-of-polymeric-fluorescent-organic-nanoparticles-based-on-the-self-polymerization-of-dopamine-for-biological-imaging
#15
Yingge Shi, Ruming Jiang, Meiying Liu, Lihua Fu, Guangjian Zeng, Qing Wan, Liucheng Mao, Fengjie Deng, Xiaoyong Zhang, Yen Wei
Polymeric fluorescent organic nanoparticles (polymer-FONs) have raised considerable research attention for biomedical applications owing to their advantages as compared with fluorescent inorganic nanoparticles and small organic molecules. In this study, we presented an efficient, facile and environment-friendly strategy to produce polymer-FONs, which relied on the self-polymerization of dopamine and polyethyleneimine (PEI) in rather mild conditions. To obtain the final polymer-FONs, aldehyde group-containing copolymers (named as poly(UA-co-PEGMA)) were synthesized by reversible addition-fragmentation chain-transfer polymerization using polyethylene glycol methyl ether methacrylate (PEGMA) and 1-undecen-10-al (UA) as monomers...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28529838/large-scale-energy-budget-of-impulsive-magnetic-reconnection-theory-and-simulation
#16
S A Kiehas, N N Volkonskaya, V S Semenov, N V Erkaev, I V Kubyshkin, I V Zaitsev
We evaluate the large-scale energy budget of magnetic reconnection utilizing an analytical time-dependent impulsive reconnection model and a numerical 2-D MHD simulation. With the generalization to compressible plasma, we can investigate changes in the thermal, kinetic, and magnetic energies. We study these changes in three different regions: (a) the region defined by the outflowing plasma (outflow region, OR), (b) the region of compressed magnetic fields above/below the OR (traveling compression region, TCR), and (c) the region trailing the OR and TCR (wake)...
March 2017: Journal of Geophysical Research. Space Physics
https://www.readbyqxmd.com/read/28527566/abnormalities-in-high-energy-phosphate-metabolism-in-first-episode-bipolar-disorder-measured-using-31-p-magnetic-resonance-spectroscopy
#17
Fei Du, Cagri Yuksel, Virginie-Anne Chouinard, Polly Huynh, Kyle Ryan, Bruce M Cohen, Dost Öngür
BACKGROUND: Brain energy metabolism is critical for supporting synaptic function and information processing. A growing body of evidence suggests abnormalities in brain bioenergetics in psychiatric disorders, including both bipolar disorder (BD) and schizophrenia. (31)P magnetic resonance spectroscopy provides a noninvasive window into these processes in vivo. Using this approach, we previously showed that patients with BD show normal adenosine triphosphate (ATP) and phosphocreatine levels at rest but cannot maintain normal ATP levels in the visual cortex during times of high energy demand (photic stimulation)...
April 7, 2017: Biological Psychiatry
https://www.readbyqxmd.com/read/28527446/single-molecule-spin-orientation-control-by-an-electric-field
#18
Yachao Zhang
We report the effects of an electric field E on the spin orientations of nickelocene (Nc) deposited on the Cu surfaces by means of first-principles calculations. We employ the Hubbard-U corrected van der Waals density functional to take into account the strong correlation effects of the localized 3d electrons and the non-covalent binding involved in the molecule-surface coupling. We show that the deposited Nc molecule can switch between in-plane (in small E-field) and perpendicular magnetization (in large E-field)...
May 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28526848/room-temperature-magnetism-in-carbon-dots-and-enhanced-ferromagnetism-in-carbon-dots-polyaniline-nanocomposite
#19
Jian Liu, Hong Bi, Paulo Cesar Morais, Xiang Zhang, Fapei Zhang, Lin Hu
Room temperature magnetic ordering is reported for very small carbon dots (CDs), mat-like polyaniline nanofibers (Mat-PANI) and a composite of CDs@Mat-PANI containing 0.315 wt% CDs. We have found saturation magnetization (M S ) of CDs, Mat-PANI and CDs@Mat-PANI at 5 (20/300) K equals to 0.0079 (0.0048/0.0019), 0.0116 (0.0065/0.0055) and 0.0349 (0.0085/0.0077) emu/g, respectively. The M S enhancement in CDs@Mat-PANI (200% and 40% at 5 K and 300 K, respectively) is attributed to electron transfer from Mat-PANI imine N-atoms to the encapsulated CDs...
May 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28526431/measurement-of-apt-using-a-combined-cert-arex-approach-with-varying-duty-cycles
#20
Zhongliang Zu, Hua Li, Junzhong Xu, Xiao-Yong Zhang, Moritz Zaiss, Ke Li, Mark D Does, John C Gore, Daniel F Gochberg
The goal is to develop an imaging method where contrast reflects amide-water magnetization exchange, with minimal signal contributions from other sources. Conventional chemical exchange saturation transfer (CEST) imaging of amides (often called amide proton transfer, or APT, and quantified by the metric MTRasym) is confounded by several factors unrelated to amides, such as aliphatic protons, water relaxation, and macromolecular magnetization transfer. In this work, we examined the effects of combining our previous chemical exchange rotation (CERT) approach with the non-linear AREX method while using different duty cycles (DC) for the label and reference scans...
May 17, 2017: Magnetic Resonance Imaging
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