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Magnetization transfer

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https://www.readbyqxmd.com/read/28345352/metal-free-photoinduced-electron-transfer-atom-transfer-radical-polymerization-integrated-with-bio-inspired-polydopamine-chemistry-as-a-green-strategy-for-surface-engineering-of-magnetic-nanoparticles
#1
Yang Yang, Xuegang Liu, Gang Ye, Shan Zhu, Zhe Wang, Xiaomei Huo, Krzysztof Matyjaszewski, Yuexiang Lu, Jing Chen
Developing green and efficient technologies for surface modification of magnetic nanoparticles (MNPs) is of crucial importance for their biomedical and environmental applications. This study reports, for the first time, a novel strategy by integrating metal-free photoinduced electron transfer-atom transfer radical polymerization (PET-ATRP) with the bio-inspired polydopamine (PDA) chemistry for controlled architecture of functional polymer brushes from MNPs. Conformal PDA encapsulation layers were initially generated on the surfaces of MNPs, which served as the protective shells while providing an ideal platform for tethering 2-bromo-2-phenylacetic acid (BPA), a highly efficient initiator...
March 27, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28342214/real-time-fmri-neurofeedback-in-adolescents-with-attention-deficit-hyperactivity-disorder
#2
Analucia A Alegria, Melanie Wulff, Helen Brinson, Gareth J Barker, Luke J Norman, Daniel Brandeis, Daniel Stahl, Anthony S David, Eric Taylor, Vincent Giampietro, Katya Rubia
Attention Deficit Hyperactivity Disorder (ADHD) is associated with poor self-control, underpinned by inferior fronto-striatal deficits. Real-time functional magnetic resonance neurofeedback (rtfMRI-NF) allows participants to gain self-control over dysregulated brain regions. Despite evidence for beneficial effects of electrophysiological-NF on ADHD symptoms, no study has applied the spatially superior rtfMRI-NF neurotherapy to ADHD. A randomized controlled trial tested the efficacy of rtfMRI-NF of right inferior prefrontal cortex (rIFG), a key region that is compromised in ADHD and upregulated with psychostimulants, on improvement of ADHD symptoms, cognition, and inhibitory fMRI activation...
March 25, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28341327/importance-of-the-structure-and-nanoporosity-of-organic-matter-on-the-desorption-kinetics-of-benzo-a-pyrene-in-sediments
#3
Youda Huang, Dainan Zhang, Dandan Duan, Yu Yang, Yongqiang Xiong, Yong Ran
The desorption kinetics and mechanism were investigated using a Tenax extraction technique on different sediments spiked with radiocarbon-labeled benzo[a]pyrene (BaP). Five sedimentary fractions were sequentially fractionated, and the only nonhydrolyzable organic carbon fractions (NHC) were characterized using advanced solid-state (13)C nuclear magnetic resonance spectroscopy (NMR), improved six end-member model, and a CO2 gas adsorption technique. The sediments contained high percentages of algaenan and/or sporopollenin but low percentages of black carbon and lignin...
March 22, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28338389/somatosensory-electrical-stimulation-does-not-augment-motor-skill-acquisition-and-intermanual-transfer-in-healthy-young-adults-a-pilot-study
#4
János Négyesi, Menno P Veldman, Kelly M M Berghuis, Marie Javet, József Tihanyi, Tibor Hortobágyi
Sensory input can modify motor function and magnify interlimb transfer. We examined the effects of low-intensity somatosensory electrical stimulation (SES) on motor practice-induced (MP) skill acquisition and intermanual transfer. Participants practiced a visuomotor skill for 25 minutes and received SES to the practice or the transfer arm. Responses to single- and double pulse transcranial magnetic stimulation (TMS) were measured in both extensor carpi radialis. SES did not further increase skill acquisition (RMP: 30...
March 24, 2017: Motor Control
https://www.readbyqxmd.com/read/28338011/towards-sub-nanometer-real-space-observation-of-spin-and-orbital-magnetism-at-the-fe-mgo-interface
#5
Thomas Thersleff, Shunsuke Muto, Mirosław Werwiński, Jakob Spiegelberg, Yaroslav Kvashnin, Björgvin Hjӧrvarsson, Olle Eriksson, Ján Rusz, Klaus Leifer
While the performance of magnetic tunnel junctions based on metal/oxide interfaces is determined by hybridization, charge transfer, and magnetic properties at the interface, there are currently only limited experimental techniques with sufficient spatial resolution to directly observe these effects simultaneously in real-space. In this letter, we demonstrate an experimental method based on Electron Magnetic Circular Dichroism (EMCD) that will allow researchers to simultaneously map magnetic transitions and valency in real-space over interfacial cross-sections with sub-nanometer spatial resolution...
March 24, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28336961/voltage-induced-interface-reconstruction-and-electrical-instability-of-the-ferromagnet-semiconductor-device
#6
Shu-Jui Chang, Po-Chun Chang, Wen-Chin Lin, Shao-Hua Lo, Liang-Chun Chang, Shang-Fan Lee, Yuan-Chieh Tseng
Using x-ray magnetic spectroscopy with in-situ electrical characterizations, we investigated the effects of external voltage on the spin-electronic and transport properties at the interface of a Fe/ZnO device. Layer-, element-, and spin-resolved information of the device was obtained by cross-tuning of the x-ray mode and photon energy, when voltage was applied. At the early stage of the operation, the device exhibited a low-resistance state featuring robust Fe-O bonds. However, the Fe-O bonds were broken with increasing voltage...
March 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28336426/sar-simulations-safety
#7
Thomas M Fiedler, Mark E Ladd, Andreas K Bitz
At ultra-high fields, the assessment of radiofrequency (RF) safety presents several new challenges compared to low-field systems. Multi-channel RF transmit coils in combination with parallel transmit techniques produce time-dependent and spatially varying power loss densities in the tissue. Further, in ultra-high-field systems, localized field effects can be more pronounced due to a transition from the quasistationary to the electromagnetic field regime. Consequently, local information on the RF field is required for reliable RF safety assessment as well as for monitoring of RF exposure during MR examinations...
March 20, 2017: NeuroImage
https://www.readbyqxmd.com/read/28335790/physical-mechanism-and-modeling-of-heat-generation-and-transfer-in-magnetic-fluid-hyperthermia-through-n%C3%A3-elian-and-brownian-relaxation-a-review
#8
REVIEW
Suriyanto, E Y K Ng, S D Kumar
Current clinically accepted technologies for cancer treatment still have limitations which lead to the exploration of new therapeutic methods. Since the past few decades, the hyperthermia treatment has attracted the attention of investigators owing to its strong biological rationales in applying hyperthermia as a cancer treatment modality. Advancement of nanotechnology offers a potential new heating method for hyperthermia by using nanoparticles which is termed as magnetic fluid hyperthermia (MFH). In MFH, superparamagnetic nanoparticles dissipate heat through Néelian and Brownian relaxation in the presence of an alternating magnetic field...
March 23, 2017: Biomedical Engineering Online
https://www.readbyqxmd.com/read/28334906/conformational-polymorphism-or-structural-invariance-in-dna-photoinduced-lesions-implications-for-repair-rates
#9
François Dehez, Hugo Gattuso, Emmanuelle Bignon, Christophe Morell, Elise Dumont, Antonio Monari
DNA photolesions constitute a particularly deleterious class of molecular defects responsible for the insurgence of a vast majority of skin malignant tumors. Dimerization of two adjacent thymines or cytosines mostly gives rise to cyclobutane pyrimidine dimers (CPD) and pyrimidine(6-4)pyrimidone 64-PP as the most common defects. We perform all-atom classical simulations, up to 2 μs, of CPD and 64-PP embedded in a 16-bp duplex, which reveal the constrasted behavior of the two lesions. In particular we evidence a very limited structural deformation induced by CPD while 64-PP is characterized by a complex structural polymorphism...
February 28, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/28330842/monocrotaline-induces-endothelial-injury-and-pulmonary-hypertension-by-targeting-the-extracellular-calcium-sensing-receptor
#10
Rui Xiao, Yuan Su, Tian Feng, Mengxiang Sun, Bingxun Liu, Jiwei Zhang, Yankai Lu, Jiansha Li, Tao Wang, Liping Zhu, Qinghua Hu
BACKGROUND: Monocrotaline has been widely used to establish an animal model of pulmonary hypertension. The molecular target underlying monocrotaline-induced pulmonary artery endothelial injury and pulmonary hypertension remains unknown. The extracellular calcium-sensing receptor (CaSR) and particularly its extracellular domain hold the potential structural basis for monocrotaline to bind. This study aimed to reveal whether monocrotaline induces pulmonary hypertension by targeting the CaSR...
March 22, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/28330349/coherent-manipulation-of-non-thermal-spin-order-in-optical-nuclear-polarization-experiments
#11
Gerd Buntkowsky, Konstantin L Ivanov, Herbert Zimmermann, Hans-Martin Vieth
Time resolved measurements of Optical Nuclear Polarization (ONP) have been performed on hyperpolarized triplet states in molecular crystals created by light excitation. Transfer of the initial electron polarization to nuclear spins has been studied in the presence of radiofrequency excitation; the experiments have been performed with different pulse sequences using different doped molecular systems. The experimental results clearly demonstrate the dominant role of coherent mechanisms of spin order transfer, which manifest themselves in well pronounced oscillations...
March 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28327718/can-charged-colloidal-particles-increase-the-thermoelectric-energy-conversion-efficiency
#12
Thomas J Salez, Bo Tao Huang, Maud Rietjens, Marco Bonetti, Cécile Wiertel-Gasquet, Michel Roger, Cleber Lopes Filomeno, Emmanuelle Dubois, Régine Perzynski, Sawako Nakamae
Currently, liquid thermocells are receiving increasing attention as an inexpensive alternative to conventional solid-state thermoelectrics for low-grade waste heat recovery applications. Here we present a novel path to increase the Seebeck coefficient of liquid thermoelectric materials using charged colloidal suspensions; namely, ionically stabilized magnetic nanoparticles (ferrofluids) dispersed in aqueous potassium ferro-/ferri-cyanide electrolytes. The dependency of thermoelectric potential on experimental parameters such as nanoparticle concentration and types of solute ions (lithium citrate and tetrabutylammonium citrate) is examined to reveal the relative contributions from the thermogalvanic potential of redox couples and the entropy of transfer of nanoparticles and ions...
March 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28327054/effects-of-low-frequency-repetitive-transcranial-magnetic-stimulation-and-neuromuscular-electrical-stimulation-on-upper-extremity-motor-recovery-in-the-early-period-after-stroke-a-preliminary-study
#13
Aliye Tosun, Sabiha Türe, Ayhan Askin, Engin Ugur Yardimci, Secil Umit Demirdal, Tülay Kurt Incesu, Ozgur Tosun, Hikmet Kocyigit, Galip Akhan, Fazıl Mustafa Gelal
OBJECTIVE: To assess the efficacy of inhibitory repetitive transcranial magnetic stimulation (rTMS) and neuromuscular electrical stimulation (NMES) on upper extremity motor function in patients with acute/subacute ischemic stroke. METHODS: Twenty-five ischemic acute/subacute stroke subjects were enrolled in this randomized controlled trial. Experimental group 1 received low frequency (LF) rTMS to the primary motor cortex of the unaffected side + physical therapy (PT) including activities to improve strength, flexibility, transfers, posture, balance, coordination, and activities of daily living, mainly focusing on upper limb movements; experimental group 2 received the same protocol combined with NMES to hand extensor muscles; and the control group received only PT...
March 22, 2017: Topics in Stroke Rehabilitation
https://www.readbyqxmd.com/read/28325514/multiparametric-approach-with-diffusion-weighted-imaging-and-dynamic-contrast-enhanced-mri-a-comparison-study-for-differentiating-between-benign-and-malignant-bone-lesions-in-adults
#14
E Oh, Y C Yoon, J H Kim, K Kim
AIM: To evaluate and compare the diagnostic performance of quantitative parameters derived from diffusion-weighted imaging (DWI) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in differentiating benign and malignant bone tumours. MATERIALS AND METHODS: Fifty-five patients (age range, 21-82 years; mean age, 55 years) underwent pretreatment MRI. Apparent diffusion coefficient (ADC) values were calculated by DWI. The DCE-MRI data were analysed for the volume transfer constant (K(trans)), extravascular extracellular volume fraction (Ve), and volume rate constant (Kep), and K(trans)/ADC ratio...
March 18, 2017: Clinical Radiology
https://www.readbyqxmd.com/read/28324930/rtms-enhanced-gamma-oscillation-through-strengthened-network-connection
#15
Mengmeng Dou, Xin Tian
Gamma oscillations emerge generally in working memory to aspect of higher cognitive functions, and typically with the interaction of brain network. How is gamma oscillatory activity influenced by the functional connection in the brain'a network? How can gamma oscillations be increased by neural modulation to result in potential benefits for working memory? The present study aims to investigate the intensity of gamma oscillations modulated by low frequency repetitive transcranial magnetic stimulation (rTMS), and the possible brain network mechanism of increased gamma oscillations during working memory task in rats...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28324908/-magnetic-sentinel-lymph-node-detection-in-prostate-cancer-after-intraprostatic-injection-of-superparamagnetic-iron-oxide-nanoparticles
#16
Alexander Winter, Svenja Engels, Tobias Kowald, Tina Susanne Paulo, Holger Gerullis, Ajay Chavan, Friedhelm Wawroschek
In prostate cancer, reliable information about the lymph node status is of great importance for accurate staging and the optimal planning of treatment. Despite recent advances in imaging, the histological detection of metastases, or pelvic lymphadenectomy (PLND), continues to be the most reliable method for lymph node staging in clinically localised prostate cancer, especially as this procedure enables the detection of small or micrometastases. Radioisotope-guided sentinel PLND (sPLND) demonstrates high sensitivity in the detection of lymph node metastases as well as low morbidity in prostate cancer because of the targeted removal of a relatively small number of lymph nodes...
March 21, 2017: Aktuelle Urologie
https://www.readbyqxmd.com/read/28321947/a-uv-cleavable-bottlebrush-polymer-with-o-nitrobenzyl-linked-side-chains
#17
Wen Zhu, Liangcai Zhang, Yongming Chen, Ke Zhang
An ultraviolet (UV)-cleavable bottlebrush polymer is synthesized using the "grafting-onto" strategy by combining living radical polymerization and copper-catalyzed azide-alkyne cycloaddition (CuAAC). In this approach, reversible addition-fragmentation chain transfer polymerization is used to prepare a poly(methylacrylate) backbone with azide side groups, while atom transfer radical polymerization is employed to prepare polystyrene (PS) side chains end-functionalized with o-nitrobenzyl (UV-cleavable) propargyl groups...
March 21, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28321915/acceleration-of-asl-based-time-resolved-mr-angiography-by-acquisition-of-control-and-labeled-images-in-the-same-shot-actress
#18
Yuriko Suzuki, Noriyuki Fujima, Tetsuo Ogino, James Alastair Meakin, Akira Suwa, Hiroyuki Sugimori, Marc Van Cauteren, Matthias J P van Osch
PURPOSE: Noncontrast 4D-MR-angiography (MRA) using arterial spin labeling (ASL) is beneficial because high spatial and temporal resolution can be achieved. However, ASL requires acquisition of labeled and control images for each phase. The purpose of this study is to present a new accelerated 4D-MRA approach that requires only a single control acquisition, achieving similar image quality in approximately half the scan time. METHODS: In a multi-phase Look-Locker sequence, the first phase was used as the control image and the labeling pulse was applied before the second phase...
March 20, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28321903/spin-lock-imaging-of-exogenous-exchange-based-contrast-agents-to-assess-tissue-ph
#19
Zhongliang Zu, Hua Li, Xiaoyu Jiang, John C Gore
PURPOSE: Some X-ray contrast agents contain exchangeable protons that give rise to exchange-based effects on MRI, including chemical exchange saturation transfer (CEST). However, CEST has poor specificity to explicit exchange parameters. Spin-lock sequences at high field are also sensitive to chemical exchange. Here, we evaluate whether spin-locking techniques can detect the contrast agent iohexol in vivo after intravenous administration, and their potential for measuring changes in tissue pH...
March 20, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28319301/successive-charge-transitions-of-unusually-high-valence-fe-3-5-charge-disproportionation-and-intermetallic-charge-transfer
#20
Yoshiteru Hosaka, Fabio Denis Romero, Noriya Ichikawa, Takashi Saito, Yuichi Shimakawa
A perovskite-structure oxide containing unusually high-valence Fe(3.5+) was obtained by high-pressure synthesis. Instability of the Fe(3.5+) in Ca0.5 Bi0.5 FeO3 is relieved first by charge disproportionation at 250 K and then by intermetallic charge transfer between A-site Bi and B-site Fe at 200 K. These previously unobserved successive charge transitions are due to competing intermetallic and disproportionation charge instabilities. Both transitions change magnetic and structural properties significantly, indicating strong coupling of charge, spin, and lattice in the present system...
March 20, 2017: Angewandte Chemie
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