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Neerav Dixit, Pascal P Stang, John M Pauly, Greig C Scott
Patients who have implanted medical devices with long conductive leads are often restricted from receiving MRI scans due to the danger of RF-induced heating near the lead tips. Phantom studies have shown that this heating varies significantly on a case-by-case basis, indicating that many patients with implanted devices can receive clinically useful MRI scans without harm. However, the difficulty of predicting RF-induced lead tip heating prior to scanning prevents numerous implant recipients from being scanned...
October 17, 2017: IEEE Transactions on Medical Imaging
Bo-Hou Xia, Yu-Zhen Hu, Su-Hui Xiong, Jie Tang, Qing-Zi Yan, Li-Mei Lin
To establish a random forest algorithm for identifying and classifying different brands of Xiasangju granules, and provide effective reference for identifying multi-index complex fingerprint. HPLC method was used to collect the fingerprint of 83 batches of Xiasangju granules from different manufacturers. The classification of Xiasangju granules samples based on chromatographic fingerprints was identified by chemometric methods including principal component analysis (PCA), partial least squares discriminate analysis (PLS-DA) and random forest analysis (RF)...
April 2017: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
Yu-Chuan Tseng, Ju-Hui Wu, Hong-Sen Chen, Chun-Ming Chen, Chun-Chan Ting
The objective of study was to investigate the correlation between the mechanical strengths [insertion torque (IT); resonance frequency (RF); and horizontal pullout strength (HPS)] and gripping volume (GV) of mini-implants. Thirty mini-implants of three types (Type A: 2 mm × 10 mm, cylindrical, titanium alloy; Type B: 2 mm × 10 mm, tapered, stainless steel; and Type C: 2 mm × 11 mm, cylindrical, titanium alloy) were inserted 7 mm into artificial bones. One-way analysis of variance and Spearman's test were applied to assess intergroup comparisons and intragroup correlations...
November 2017: Kaohsiung Journal of Medical Sciences
David J Polhemus, Rishi K Trivedi, Juan Gao, Zhen Li, Amy L Scarborough, Traci T Goodchild, Kurt J Varner, Huijing Xia, Frank W Smart, Daniel R Kapusta, David J Lefer
BACKGROUND: Sustained sympathetic activation contributes to the progression of myocardial cell injury, cardiac fibrosis, and left ventricular (LV) dysfunction in heart failure (HF). OBJECTIVES: This study investigated the effects of radiofrequency renal nerve denervation (RF-RDN) on the pathobiology of HF and the interaction between the renal sympathetic nerves and natriuretic peptide (NP) metabolism. METHODS: Spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) were subjected to 45 min of coronary artery ligation and reperfusion for 12 weeks...
October 24, 2017: Journal of the American College of Cardiology
Da-Un-Jin Jung, Rafiq Ahmad, Yoon-Bong Hahn
Herein, we fabricated nonenzymatic flexible field-effect transistor (f-FET) based glucose sensor using nickel oxide quantum dots (NiO QDs) modified zinc oxide nanorods (ZnO NRs). The ZnO NRs surfaces were coated with NiO QDs using radio frequency (RF) magnetron sputtering to enhance the electrocatalytic feature and the surface area of ZnO NRs. Under physiological conditions (pH 7.4), the nonenzymatic f-FET glucose sensor shows two linear ranges of 0.001-10mM and 10-50mM with the high sensitivity of 13.14μAcm(-2)mM(-1) and 7...
October 12, 2017: Journal of Colloid and Interface Science
Joshua R Biller, Karl F Stupic, J Moreland
We present the development of a portable dynamic nuclear polarization (DNP) instrument based on the PCI eXtensions for Instrumentation (PXI) platform. The main purpose of the instrument is for study of (1) H polarization enhancements in solution through the Overhauser mechanism at low magnetic fields. A DNP probe set was constructed for use at 6.7 mT, using a modified Alderman-Grant (MAG) resonator at 241 MHz for saturation of the electron transition. The solenoid for detection of the enhanced (1) H signal at 288 kHz was constructed with Litz wire...
October 19, 2017: Magnetic Resonance in Chemistry: MRC
Lixin Luo, Xinghua Zhao, Minjie Jiang, Haiyan Zhang, Yu Wang
Paper chromatography (PC) is a highly flexible, fast, and efficient separation method. In this study, a chromatographic paper with a chiral separation function was investigated and a paper chromatographic method for chiral separation was developed. Single-factor experiments and orthogonal tests were used to determine the optimal oxidation conditions for filter paper. The optimal conditions were that sodium periodate 4% (mass percentage), pH 2 buffer solution, reaction temperature 45℃, and reaction time 4 h...
September 8, 2017: Se Pu, Chinese Journal of Chromatography
Nour Alem, Fabrice Pellen, Guy Le Brun, Bernard Le Jeune
The hybrid lidar-radar technique is commonly used for shallow underwater target detection. This technique requires a powerful blue-green RF-modulated laser with stable microwave frequency. In this paper, a novel modulator design perfectly suited for this application is proposed. It consists of an extra-cavity modulator composed of two plane mirrors and a second-harmonic generator stage within the cavity to maximize the energy efficiency. This modulator is coupled with a picosecond Nd:YAG infrared laser source to insure the emission of a powerful pulse (up to 5 mJ)...
September 10, 2017: Applied Optics
Shalom Bloch, Shmuel Sternklar, Er'el Granot
Next-generation analog radio frequency over fiber (RFoF) links will require dispersion compensation. Most dispersion compensation methods are based on additional optical elements. Therefore, these solutions may be inadequate for low-cost channels. In this work, we suggest a novel low-cost dispersion compensation solution for RFoF links. The method is based on two properties, which are common in these links: the modulation depth in analog RFoF links is lower than in digital links (and to avoid nonlinearities, it may be deliberately set to a small value), and the data are carried by a high-frequency carrier...
August 20, 2017: Applied Optics
S Maidul Haque, Rajnarayan De, S Tripathi, C Mukherjee, A K Yadav, Dibyendu Bhattacharyya, S N Jha, N K Sahoo
Gadolinium oxide is an excellent optical material that offers high transmission in a wide wavelength range of 200-1600 nm and exhibits a high bulk refractive index of ∼1.80 at 550 nm. In the present study, a set of Gd2O3 thin films has been deposited on fused silica substrates by RF sputtering of a Gd2O3 target under various O2 to Ar flow ratios. The samples have been characterized by grazing incidence x-ray diffraction (GIXRD) to study the long range structural behavior, by GIXR to study density and surface roughness of the films, by atomic force microscopy measurements to study morphological properties, by Rutherford backscattering measurements for compositional studies, and by transmission spectrophotometry and spectroscopic ellipsometry techniques to study their optical properties...
August 1, 2017: Applied Optics
Heike Christopher, Evgeny V Kovalchuk, Hans Wenzel, Frank Bugge, Markus Weyers, Andreas Wicht, Achim Peters, Günther Tränkle
We present a compact, mode-locked diode laser system designed to emit a frequency comb in the wavelength range around 780 nm. We compare the mode-locking performance of symmetric and asymmetric double quantum well ridge-waveguide diode laser chips in an extended-cavity diode laser configuration. By reverse biasing a short section of the diode laser chip, passive mode-locking at 3.4 GHz is achieved. Employing an asymmetric double quantum well allows for generation of a mode-locked optical spectrum spanning more than 15 nm (full width at -20  dB) while the symmetric double quantum well device only provides a bandwidth of ∼2...
July 1, 2017: Applied Optics
Zeb W Barber, Calvin Harrington, R Krishna Mohan, Trent Jackson, Colton Stiffler, P B Sellin, Kristian D Merkel
The demonstration of an all-optical, ultra-high-speed, time-domain signal correlator based on spatial-spectral holographic (SSH) technology is described. The fully programmable signal correlator demonstration operates asynchronously and continuously on signals with up to 32 GHz of bandwidth and correlative filter length exceeding a time-bandwidth product of 10(4), for the equivalent of teraflop-scale processing. Experimental demonstrations are presented that show both digital and analog correlation capability using phase-shift keyed modulation formats to search plain text ASCII data sources for arbitrary phrases at continuous line rate throughputs up to 200 Gbps with minimal latency...
July 1, 2017: Applied Optics
Andrei Choukourov, Pavel Pleskunov, Daniil Nikitin, Valerii Titov, Artem Shelemin, Mykhailo Vaidulych, Anna Kuzminova, Pavel Solař, Jan Hanuš, Jaroslav Kousal, Ondřej Kylián, Danka Slavínská, Hynek Biederman
This contribution reviews plasma polymer nanoparticles produced by gas aggregation cluster sources either via plasma polymerization of volatile monomers or via radio frequency (RF) magnetron sputtering of conventional polymers. The formation of hydrocarbon, fluorocarbon, silicon- and nitrogen-containing plasma polymer nanoparticles as well as core@shell nanoparticles based on plasma polymers is discussed with a focus on the development of novel nanostructured surfaces.
2017: Beilstein Journal of Nanotechnology
Markus Göttlicher, Marcus Rohnke, Yannik Moryson, Jürgen Thomas, Joachim Sann, Anja Lode, Matthias Schumacher, Romy Schmidt, Stefan Pilz, Annett Gebert, Thomas Gemming, Jürgen Janek
BACKGROUND: Surface functionalization of orthopedic implants with pharmaceutically active agents is a modern approach to enhance osseointegration in systemically altered bone. A local release of strontium, a verified bone building therapeutic agent, at the fracture site would diminish side effects, which could occur otherwise by oral administration. Strontium surface functionalization of specially designed titanium-niobium (Ti-40Nb) implant alloy would provide an advanced implant system that is mechanically adapted to altered bone with the ability to stimulate bone formation...
2017: Biomaterials Research
Boubker Zaaimi, Lauren R Dean, Stuart N Baker
Coordinated movement requires patterned activation of muscles. In this study we examined differences in selective activation of primate upper limb muscles by cortical and sub-cortical regions. Five macaque monkeys were trained to perform a reach and grasp task, and electromyogram (EMG) was recorded from 10-24 muscles while weak single-pulse stimuli were delivered through microelectrodes inserted in the motor cortex (M1), reticular formation (RF) or cervical spinal cord (SC). Stimulus intensity was adjusted to a level just above threshold...
October 18, 2017: Journal of Neurophysiology
Eduardo Sánchez, Rubén Ferreiroa, Adrián Arias, Luis M Martínez
The center-surround organization of the receptive fields (RFs) of retinal ganglion cells highlights the presence of local contrast in visual stimuli. As RF of thalamic relay cells follow the same basic functional organization, it is often assumed that they contribute very little to alter the retinal output. However, in many species, thalamic relay cells largely outnumber their retinal inputs, which diverge to contact simultaneously several units at thalamic level. This gain in cell population as well as retinothalamic convergence opens the door to question how information about contrast is transformed at the thalamic stage...
September 7, 2017: International Journal of Neural Systems
Ju Hwan Kim, Hyo-Jeong Kim, Da-Hyeon Yu, Hee-Seok Kweon, Yang Hoon Huh, Hak Rim Kim
We studied the effects of radiofrequency electromagnetic fields (RF-EMFs) exposure on neuronal functions of mice. Particularly, we focused on RF-EMF effects on synaptic vesicles (SVs), which store neurotransmitters at axon terminals or synaptic boutons. C57 BL/6 mice were exposed to 835 MHz RF-EMF (4.0 W/kg SAR, for 5 h daily) and alterations in SVs at presynaptic terminals in the cerebral cortex were determined. Ultrastructure of randomly selected cortical neurons was observed using typical electron microscopy and bio-high voltage electron microscopy (Bio-HVEM) methods, which enable the estimation of the numbers and size of SVs...
2017: PloS One
Lucas Christoph Adam, Nikitha Murali, Julius Chapiro, Jean-François Geschwind
In an effort to improve the technical success rates and clinical outcomes of radiofrequency (RF) ablation, Yan et al validated the use of a tumor-penetrating peptide and thermosensitive doxorubicin (DOX)-loaded nanoparticles in combination with RF ablation in a hepatocellular carcinoma mouse model. By achieving higher chemotherapeutic drug concentrations in target lesions, fewer toxic effects, and improved survival end points in an animal tumor model, the authors conclude that superior tumor treatment with RF ablation is possible when combined with molecular-targeted drug delivery systems...
November 2017: Radiology
Pooja Viswanathan, Andreas Nieder
The concept of receptive field (RF) describes the responsiveness of neurons to sensory space. Neurons in the primate association cortices have long been known to be spatially selective but a detailed characterization and direct comparison of RFs between frontal and parietal association cortices is missing. We sampled the RFs of a large number of neurons from two interconnected areas of the frontal and parietal lobes, the dorsolateral prefrontal cortex (dlPFC) and ventral intraparietal area (VIP), of rhesus monkeys by systematically presenting a moving bar during passive fixation...
October 17, 2017: European Journal of Neuroscience
Peter Wells, Marc Dubuc, George J Klein, Dan Dan, Jean-Francois Roux, Evan Lockwood, Marcio Sturmer, David Dunbar, Paul Novak, Arun Rao, Brett J Peterson, Fred Kueffer, Kenneth A Ellenbogen
INTRODUCTION: Radiofrequency (RF) ablation is effective for slow pathway ablation, but carries a risk of inadvertent AV block requiring permanent pacing. By comparison, cryoablation with a 4 mm distal electrode catheter has not been reported to cause permanent AV block but has been shown to be less effective than RF ablation. We sought to define the safety and efficacy of a 6 mm distal electrode cryoablation catheter for slow pathway ablation in patients with atrioventricular nodal reentry tachycardia (AVNRT)...
October 17, 2017: Journal of Cardiovascular Electrophysiology
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