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Sample records for 3t functional magnetic

  1. BOLD contrast on a 3 T magnet: detectability of the motor areas.

    PubMed

    Nakai, T; Matsuo, K; Kato, C; Okada, T; Moriya, T; Isoda, H; Takehara, Y; Sakahara, H

    2001-01-01

    To predict the potential and the limitations of functional MRI (fMRI) with a very high field magnet, the detectability and reproducibility of activation were evaluated by comparing the activation induced by a sequential finger movement task at 1.5 T with that at 3 T. The detectability of the premotor area, supplementary motor area (SMA), and ipsilateral sensorimotor area (SM1) showed significant improvement at 3 T. On the other hand, the detectability of contralateral SM1 was not significantly different between 1.5 and 3 T. The degree of activation was proportional to task demand in the ipsilateral SM1 and SMA, whereas that in the contralateral SM1 and SMA was not. FMRI with a 3 T magnet has greater potential for detection of neuronal activation as a functional network. These observations indicated that task demand and static magnetic field strength should be considered in interpretation of fMRI data for clinical usage.

  2. Malformations of cortical development: 3T magnetic resonance imaging features

    PubMed Central

    Battal, Bilal; Ince, Selami; Akgun, Veysel; Kocaoglu, Murat; Ozcan, Emrah; Tasar, Mustafa

    2015-01-01

    Malformation of cortical development (MCD) is a term representing an inhomogeneous group of central nervous system abnormalities, referring particularly to embriyological aspect as a consequence of any of the three developmental stages, i.e., cell proliferation, cell migration and cortical organization. These include cotical dysgenesis, microcephaly, polymicrogyria, schizencephaly, lissencephaly, hemimegalencephaly, heterotopia and focal cortical dysplasia. Since magnetic resonance imaging is the modality of choice that best identifies the structural anomalies of the brain cortex, we aimed to provide a mini review of MCD by using 3T magnetic resonance scanner images. PMID:26516429

  3. Event-related dynamics of glutamate and BOLD effects measured using functional magnetic resonance spectroscopy (fMRS) at 3T in a repetition suppression paradigm.

    PubMed

    Apšvalka, Dace; Gadie, Andrew; Clemence, Matthew; Mullins, Paul G

    2015-09-01

    Proton MR spectroscopy ((1)H-MRS) complements other brain research methods by providing measures of neurometabolites noninvasively in a localized brain area. Improvements in MR scanner technologies, and data acquisition and analysis methods should allow functional (1)H-MRS (fMRS) to measure neurometabolite concentration changes during task-induced brain activation. The aim of the current study was to further develop event-related fMRS at 3T to investigate glutamate dynamics in response to repetition suppression. A secondary aim was to investigate the relationship between blood-oxygen-level-dependent (BOLD) responses and glutamate dynamics in the same paradigm at the same time. A novel approach of interleaved water-suppressed (metabolite) and unsuppressed (water) fMRS was used to simultaneously detect the event-related dynamics of glutamate and BOLD signal to repetition suppression in the lateral occipital cortex of thirteen (N=13) volunteers. On average, (1)H-MRS-visible glutamate increased after novel visual stimuli presentations by 12% and decreased by 11-13% on repeated compared to novel presentations. The BOLD signal, as measured by water peak amplitude changes, showed significant difference between Task and Rest trials, and, on a GLM based analysis of the time series, demonstrated a significant difference between the novel and repeated trials, however appeared to be decoupled from the glutamate response as no correlation was found between the two. These results are the first demonstration that reductions in neuronal activity typical of repetition suppression effects are reflected by reduced glutamatergic and BOLD measures, that glutamate and BOLD responses may not be coupled as previously thought, and that these changes and relationships can be measured simultaneously using event-related fMRS at 3T.

  4. A 3 T superconducting magnet for the amy detector

    NASA Astrophysics Data System (ADS)

    Doi, Y.; Haruyama, T.; Hirabayashi, H.; Ishimoto, S.; Maki, A.; Mito, T.; Omori, T.; Terada, S.; Tsuchiya, K.

    1989-01-01

    A 3 T high field superconducting magnet was constructed for the AMY detector at the TRISTAN electron-positron storage ring. Cooldown and excitation tests of the magnet were carried out with the detector in its final configuration. The coil is made with a fully stabilized superconductor wound into an eight layer cylinder with a 2.39 m inner diameter, a 2.58 m outer diameter and 1.54 m in length. An outer jacket of thick stainless steel was shrunk-fit around the coil to provide strength to contain the magnetic forces and to serve as a liquid helium container for the pool boiling cooling system for the coil. A computer controlled refrigeration system with a capacity of 300 W at 4.4. K (100 l/h) was prepared to cool down the 17 t of cold mass of the magnet. It took about five days to cool down from room temperature and achieve a superconducting state, and an additional two days to completely fill the coil with liquid helium and to prepare for the excitation of the magnet. The thermal stresses on the coil support rods were evenly balanced during the cooldown, and the mechanical stresses on the support rods at full excitation (a current of 5000 A) were well below the allowed maximum. In order to verify the safe operation of the magnet system, we carried out fast discharge tests with a time constant of 21 s, which was optimized to protect the magnet from quench. The pressure rise in the helium vessel during the discharge from 5000 A was an easily manageable 1.38 × 10 5 Pa. During the fast discharge of the 5000 A excitation, the coil showed no signs of developing any normal regions. At the maximum rated current of 5000 A, the central magnetic field and the inductance were measured to be 3.0367 and 3.2 H, respectively, corresponding to a stored energy of 40 MJ, in good agreement with magnetic field calculations. During these tests and in the succeeding long term operation, the magnet showed excellent stability and reliability.

  5. Philips 3T Intera Magnetic Resonance Imaging System and Upgrade of existing MRI equipment

    SciTech Connect

    Evanochko, William T

    2004-05-14

    The objective of this proposal was twofold. First, upgrade existing MRI equipment, specifically a research 4.1T whole-body system. Second, purchase a clinical, state-of-the-art 3T MRI system tailored specifically to cardiovascular and neurological applications. This project was within the guidelines of ''Medical Applications and Measurement Science''. The goals were: [1] to develop beneficial applications of magnetic resonance imaging; [2] discover new applications of MR strategies for medical research; and [2] apply them for clinical diagnosis. Much of this proposal searched for breakthroughs in this noninvasive and nondestructive imaging technology. Finally, this proposal's activities focused on research in the basic science of chemistry, biochemistry, physics, and engineering as applied to bioengineering. The centerpiece of this grant was our 4.1T ultra-high field whole-body nuclear magnetic resonance system and the newly acquired state-of-the-art, heart and head dedicated 3T clinical MRI system. We have successfully upgraded the equipment for the 4.1T system so that it is now state-of-the-art with new gradient and radio frequency amplifiers. We also purchase a unique In Vivo EKG monitoring unit that will permit tracking clinical quality EKG signals while the patient is in a high field MR scanner. Important upgrades of a peripheral vascular coil and a state-of-the-art clinical workstation for processing complex heart images were implemented. The most recent acquisition was the purchase of a state-of-the-art Philips 3T Intera clinical MRI system. This system is unique in that the magnet is only 5 1/2 feet long compare to over 12 feet long magnet of our 4.1T MRI system. The 3T MRI system is fully functional and its use and applications are already greatly benefiting the UAB with 200-300 micron resolution brain images and diagnostic quality MR angiography of coronary arteries in less than 5 minutes.

  6. Cardiovascular magnetic resonance imaging of isolated perfused pig hearts in a 3T clinical MR scanner

    PubMed Central

    Chiribiri, Amedeo; Ishida, Masaki; Morton, Geraint; Paul, Matthias; Hussain, Shazia T.; Bigalke, Boris; Perera, Divaka; Schaeffter, Tobias; Nagel, Eike

    2012-01-01

    Purpose An isolated perfused pig heart model has recently been proposed for the development of novel methods in standard clinical magnetic resonance (MR) scanners. The original set-up required the electrical system to be within the safe part of the MR-room, which introduced significant background noise. The purpose of the current work was to refine the system to overcome this limitation so that all electrical parts are completely outside the scanner room. Methods Four pig hearts were explanted under terminal anaesthesia from large white cross landrace pigs. All hearts underwent cardiovascular magnetic resonance (CMR) scanning in the MR part of a novel combined 3T MR and x-ray fluoroscopy (XMR) suite. CMR scanning included real-time k-t SENSE functional imaging, k-t SENSE accelerated perfusion imaging and late gadolinium enhancement imaging. Interference with image quality was assessed by spurious echo imaging and compared to noise levels acquired while operating the electrical parts within the scanner room. Results Imaging was performed successfully in all hearts. The system proved suitable for isolated heart perfusion in a novel 3T XMR suite. No significant additional noise was introduced into the scanner room by our set-up. Conclusions We have substantially improved a previous version of an isolated perfused pig heart model and made it applicable for MR imaging in a state of the art clinical 3T XMR imaging suite. The use of this system should aid novel CMR sequence development and translation into clinical practice. PMID:24265875

  7. Enhanced survival of short-range magnetic correlations and frustrated interactions in R3T intermetallics

    SciTech Connect

    Baranov, Nikolai; Proshkin, Aleksei; Gubkin, Andrey; Cervellino, A.; Michor, H.; Hilsher, G.; Gerasimov, E.G.; Ehlers, Georg; Frontzek, Matthias D; Podlesnyak, Andrey A

    2012-01-01

    Elastic and inelastic neutron scattering and magnetization measurements have been used to study peculiarities of the magnetic state in R{sub 3}T compounds (R=Gd, Er, Tb; T=Ni, Co) below and above magnetic ordering temperatures. A pronounced non-Brillouin shape of the magnetization curves observed in the antiferromagnetic compounds Gd{sub 3}Ni and Tb{sub 3}Ni above their magnetic ordering temperatures together with earlier reported data about the retention of the magnetic contribution to the total specific heat of Gd{sub 3}T and anomalous behavior of the electrical resistivity above magnetic ordering temperatures are ascribed to the existence of short-range magnetic correlations in the wide temperature range in the paramagnetic state. The persistence of short-range magnetic order up to temperatures greater than 5-6 times the Neel temperature has been revealed by powder neutron diffraction measurements performed for Tb{sub 3}Ni and Tb{sub 3}Co. On the other hand, results from inelastic neutron scattering show that the low temperature magnetic excitations are strongly suppressed in both Tb{sub 3}Co and Er{sub 3}Co. It is suggested that the extended short-range magnetic correlations, which turn out to be an inherent feature of R{sub 3}T type compounds, are due to the layered crystal structure and to the difference between geometrically frustrated intra-layer exchange interactions and inter-layer exchange.

  8. T2 FLAIR artifacts at 3-T brain magnetic resonance imaging.

    PubMed

    Lavdas, Eleftherios; Tsougos, Ioannis; Kogia, Stella; Gratsias, Georgios; Svolos, Patricia; Roka, Violetta; Fezoulidis, Ioannis V; Kapsalaki, Eftychia

    2014-01-01

    The purpose of this retrospective clinical study was to identify and evaluate the presence and frequency of T2 FLAIR artifacts on brain MRI studies performed at 3 T. We reviewed axial T2 FLAIR images in 200 consecutive unremarkable brain MRI studies performed at 3 T. All studies were reviewed for the presence of artifacts caused by pulsatile CSF flow, magnetic susceptibility and no nulling of the CSF signal. T2 FLAIR images introduce several artifacts that may degrade image quality and mimic pathology. Knowledge of these artifacts and increased severity and frequency at 3 T is of particular importance in avoiding a misdiagnosis.

  9. [High resolution (3 T) magnetic resonance neurography of the sciatic nerve].

    PubMed

    Cejas, C; Aguilar, M; Falcón, L; Caneo, N; Acuña, M C

    2013-01-01

    Magnetic resonance (MR) neurography refers to a set of techniques that enable the structure of the peripheral nerves and nerve plexuses to be evaluated optimally. New two-dimensional and three-dimensional neurographic sequences, in particular in 3T scanners, achieve excellent contrast between the nerve and perineural structures. MR neurography makes it possible to distinguish between the normal fascicular pattern of the nerve and anomalies like inflammation, trauma, and tumor that can affect nerves. In this article, we describe the structure of the sciatic nerve, its characteristics on MR neurography, and the most common diseases that affect it.

  10. Successful serial imaging of the mouse cerebral arteries using conventional 3-T magnetic resonance imaging

    PubMed Central

    Makino, Hiroshi; Hokamura, Kazuya; Natsume, Takahiro; Kimura, Tetsuro; Kamio, Yoshinobu; Magata, Yasuhiro; Namba, Hiroki; Katoh, Takasumi; Sato, Shigehito; Hashimoto, Tomoki; Umemura, Kazuo

    2015-01-01

    Serial imaging studies can be useful in characterizing the pathologic and physiologic remodeling of cerebral arteries in various mouse models. We tested the feasibility of using a readily available, conventional 3-T magnetic resonance imaging (MRI) to serially image cerebrovascular remodeling in mice. We utilized a mouse model of intracranial aneurysm as a mouse model of the dynamic, pathologic remodeling of cerebral arteries. Aneurysms were induced by hypertension and a single elastase injection into the cerebrospinal fluid. For the mouse cerebrovascular imaging, we used a conventional 3-T MRI system and a 40-mm saddle coil. We used non-enhanced magnetic resonance angiography (MRA) to detect intracranial aneurysm formation and T2-weighted imaging to detect aneurysmal subarachnoid hemorrhage. A serial MRI was conducted every 2 to 3 days. MRI detection of aneurysm formation and subarachnoid hemorrhage was compared against the postmortem inspection of the brain that was perfused with dye. The imaging times for the MRA and T2-weighted imaging were 3.7±0.5 minutes and 4.8±0.0 minutes, respectively. All aneurysms and subarachnoid hemorrhages were correctly identified by two masked observers on MRI. This MRI-based serial imaging technique was useful in detecting intracranial aneurysm formation and subarachnoid hemorrhage in mice. PMID:25920958

  11. Contributed review: nuclear magnetic resonance core analysis at 0.3 T.

    PubMed

    Mitchell, Jonathan; Fordham, Edmund J

    2014-11-01

    Nuclear magnetic resonance (NMR) provides a powerful toolbox for petrophysical characterization of reservoir core plugs and fluids in the laboratory. Previously, there has been considerable focus on low field magnet technology for well log calibration. Now there is renewed interest in the study of reservoir samples using stronger magnets to complement these standard NMR measurements. Here, the capabilities of an imaging magnet with a field strength of 0.3 T (corresponding to 12.9 MHz for proton) are reviewed in the context of reservoir core analysis. Quantitative estimates of porosity (saturation) and pore size distributions are obtained under favorable conditions (e.g., in carbonates), with the added advantage of multidimensional imaging, detection of lower gyromagnetic ratio nuclei, and short probe recovery times that make the system suitable for shale studies. Intermediate field instruments provide quantitative porosity maps of rock plugs that cannot be obtained using high field medical scanners due to the field-dependent susceptibility contrast in the porous medium. Example data are presented that highlight the potential applications of an intermediate field imaging instrument as a complement to low field instruments in core analysis and for materials science studies in general.

  12. Contributed Review: Nuclear magnetic resonance core analysis at 0.3 T

    SciTech Connect

    Mitchell, Jonathan Fordham, Edmund J.

    2014-11-15

    Nuclear magnetic resonance (NMR) provides a powerful toolbox for petrophysical characterization of reservoir core plugs and fluids in the laboratory. Previously, there has been considerable focus on low field magnet technology for well log calibration. Now there is renewed interest in the study of reservoir samples using stronger magnets to complement these standard NMR measurements. Here, the capabilities of an imaging magnet with a field strength of 0.3 T (corresponding to 12.9 MHz for proton) are reviewed in the context of reservoir core analysis. Quantitative estimates of porosity (saturation) and pore size distributions are obtained under favorable conditions (e.g., in carbonates), with the added advantage of multidimensional imaging, detection of lower gyromagnetic ratio nuclei, and short probe recovery times that make the system suitable for shale studies. Intermediate field instruments provide quantitative porosity maps of rock plugs that cannot be obtained using high field medical scanners due to the field-dependent susceptibility contrast in the porous medium. Example data are presented that highlight the potential applications of an intermediate field imaging instrument as a complement to low field instruments in core analysis and for materials science studies in general.

  13. An optically powered CMOS tracking system for 3 T magnetic resonance environment.

    PubMed

    Sarioglu, Baykal; Tumer, Murat; Cindemir, Umut; Camli, Berk; Dundar, Gunhan; Ozturk, Cengizhan; Yalcinkaya, Arda D

    2015-02-01

    In this work, a fully optical Complementary Metal Oxide Semiconductor (CMOS) based catheter tracking system designed for 3 T Magnetic Resonance Imaging (MRI) environment is presented. The system aims to solve the Radio Frequency (RF) induced heating problem present in conventional wired catheter tracking systems used in MRI. It is based on an integrated circuit, consisting of a receiver and an optical power supply unit. The optical power supply unit includes a single on-chip photodiode and a DC-DC converter that boosts the low photodiode voltage output to voltages greater than 1.5 V. Through an optically driven switch, the accumulated charge on an a storage capacitor is transferred to the rest of the system. This operation is novel in the way that it is fully optical and the switch control is done through modulation of the applied light. An on-chip local oscillator signal for the receiver is avoided by application of an RF signal that is generated by the MRI machine at the receiving period. The signals received by a micro-coil antenna are processed by the on-chip direct conversion receiver. The processed signal is then transferred, also optically, to the outside world for tracking purposes. The frequency encoding method is used for MRI tracking. Operation with various levels of external optical power does not generate noticeble temperature increase in the system. The overall system is successfully tested in a 3 T MRI machine to demonstrate its full operation.

  14. Magnetic Levitation of MC3T3 Osteoblast Cells as a Ground-Based Simulation of Microgravity.

    PubMed

    Hammer, Bruce E; Kidder, Louis S; Williams, Philip C; Xu, Wayne Wenzhong

    2009-11-01

    Diamagnetic samples placed in a strong magnetic field and a magnetic field gradient experience a magnetic force. Stable magnetic levitation occurs when the magnetic force exactly counter balances the gravitational force. Under this condition, a diamagnetic sample is in a simulated microgravity environment. The purpose of this study is to explore if MC3T3-E1 osteoblastic cells can be grown in magnetically simulated hypo-g and hyper-g environments and determine if gene expression is differentially expressed under these conditions. The murine calvarial osteoblastic cell line, MC3T3-E1, grown on Cytodex-3 beads, were subjected to a net gravitational force of 0, 1 and 2 g in a 17 T superconducting magnet for 2 days. Microarray analysis of these cells indicated that gravitational stress leads to up and down regulation of hundreds of genes. The methodology of sustaining long-term magnetic levitation of biological systems are discussed. PMID:20052306

  15. Magnetic Levitation of MC3T3 Osteoblast Cells as a Ground-Based Simulation of Microgravity.

    PubMed

    Hammer, Bruce E; Kidder, Louis S; Williams, Philip C; Xu, Wayne Wenzhong

    2009-11-01

    Diamagnetic samples placed in a strong magnetic field and a magnetic field gradient experience a magnetic force. Stable magnetic levitation occurs when the magnetic force exactly counter balances the gravitational force. Under this condition, a diamagnetic sample is in a simulated microgravity environment. The purpose of this study is to explore if MC3T3-E1 osteoblastic cells can be grown in magnetically simulated hypo-g and hyper-g environments and determine if gene expression is differentially expressed under these conditions. The murine calvarial osteoblastic cell line, MC3T3-E1, grown on Cytodex-3 beads, were subjected to a net gravitational force of 0, 1 and 2 g in a 17 T superconducting magnet for 2 days. Microarray analysis of these cells indicated that gravitational stress leads to up and down regulation of hundreds of genes. The methodology of sustaining long-term magnetic levitation of biological systems are discussed.

  16. Magnetic Levitation of MC3T3 Osteoblast Cells as a Ground-Based Simulation of Microgravity

    PubMed Central

    Kidder, Louis S.; Williams, Philip C.; Xu, Wayne Wenzhong

    2009-01-01

    Diamagnetic samples placed in a strong magnetic field and a magnetic field gradient experience a magnetic force. Stable magnetic levitation occurs when the magnetic force exactly counter balances the gravitational force. Under this condition, a diamagnetic sample is in a simulated microgravity environment. The purpose of this study is to explore if MC3T3-E1 osteoblastic cells can be grown in magnetically simulated hypo-g and hyper-g environments and determine if gene expression is differentially expressed under these conditions. The murine calvarial osteoblastic cell line, MC3T3-E1, grown on Cytodex-3 beads, were subjected to a net gravitational force of 0, 1 and 2 g in a 17 T superconducting magnet for 2 days. Microarray analysis of these cells indicated that gravitational stress leads to up and down regulation of hundreds of genes. The methodology of sustaining long-term magnetic levitation of biological systems are discussed. PMID:20052306

  17. Numerical study of remote detection outside the magnet with travelling wave Magnetic Resonance Imaging at 3T

    NASA Astrophysics Data System (ADS)

    López, M.; Vázquez, F.; Solís-Nájera, S.; Rodriguez, A. O.

    2015-01-01

    The use of the travelling wave approach for high magnetic field magnetic resonance imaging has been used recently with very promising results. This approach offer images one with greater field-of-view and a reasonable signal-to-noise ratio using a circular waveguide. This scheme has been proved to be successful at 7 T and 9.4 T with whole-body imager. Images have also been acquired with clinical magnetic resonance imaging systems whose resonant frequencies were 64 MHz and 128 MHz. These results motivated the use of remote detection of the magnetic resonance signal using a parallel-plate waveguide together with 3 T clinical scanners, to acquired human leg images. The cut-off frequency of this waveguide is zero for the principal mode, allowing us to overcome the barrier of transmitting waves at lower frequency than 300 MHz or 7 T for protons. These motivated the study of remote detection outside the actual magnet. We performed electromagnetic field simulations of a parallel-plate waveguide and a phantom. The signal transmission was done at 128 MHz and using a circular surface coil located almost 200 cm away for the magnet isocentre. Numerical simulations demonstrated that the magnetic field of the principal mode propagate inside a waveguide outside the magnet. Numerical results were compared with previous experimental-acquired image data under similar conditions.

  18. Twist-3 T-odd fragmentation functions G⊥ and G˜⊥ in a spectator model

    NASA Astrophysics Data System (ADS)

    Yang, Yongliang; Lu, Zhun; Schmidt, Ivan

    2016-10-01

    We present a calculation of the twist-3 T-odd chiral-even fragmentation functions G⊥ and G˜⊥ using a spectator model. We consider the effect gluon exchange to calculate all necessary one-loop diagrams for the quark-quark and quark-gluon-quark correlation functions. We find that the gluon loops corrections generate non-zero contribution to these two fragmentation function. We numerically calculate their half-kT moments by integrating over the transverse momentum and also verify the equation of motion relation among G⊥, G˜⊥ and the Collins function.

  19. [Experimental evaluation of the occupational exposure to static magnetic fields on a 3 T magnetic resonance scanner].

    PubMed

    Moro, Luca; Alabiso, Francesco; Parisoli, Francesco; Frigerio, Francesco

    2013-01-01

    The recent postponement until 31 October 2013 of the deadline for transposition of the EU Directive 2004/40/EC, concerning the minimum health requirementsfor the exposure of workers to the risks arising from electromagnetic fields between 0 and 300 GHz, keeps on suspending the Italian law which was aimed to implement the EU regulations on the occupational exposure to electromagnetic fields, including those generated by Magnetic Resonance Imaging (MRI) units. Waiting for the revision of the exposure limits proposed by the EU Directive taking into account results from new studies and evolution of knowledge, the time-weighted values of static magnetic field proposed by the Italian Ministry of Health (D.M 02/08/91) still survive as limits for worker's exposure. The comparison between the proposed thresholds and the time required to position patients allows to calculate how long the MRI staff can stay at different values of static magnetic field, i.e. the maximum workload of each worker. In order to evaluate more accurately how many time the members of MRI staff are near the magnet bore and the real value of worker's exposure to the static magnetic field during the handling of patients, a teslameter Metrolab THM1176-PDA was used. Personal exposure measurements on the radiologists and the radiographers who worked on a 3 T GE Healthcare Discovery 750 MR were carried out during the positioning of self-sufficient and collaborative patients. The sensor was worn at the chest level on the side that was nearest to the magnet bore. Results show wide variations occurring between individual working procedures concerning the handling of patients, especially during the initial position phase. The mean values of the time spent by radiographers inside the magnet room (B > 0.5 mT) to place the patient and to take him outside at the end of the exam were respectively 220 and 127 seconds. The mean value of the time spent by radiologists was 162 seconds when they had to insert a peripheral

  20. [Experimental evaluation of the occupational exposure to static magnetic fields on a 3 T magnetic resonance scanner].

    PubMed

    Moro, Luca; Alabiso, Francesco; Parisoli, Francesco; Frigerio, Francesco

    2013-01-01

    The recent postponement until 31 October 2013 of the deadline for transposition of the EU Directive 2004/40/EC, concerning the minimum health requirementsfor the exposure of workers to the risks arising from electromagnetic fields between 0 and 300 GHz, keeps on suspending the Italian law which was aimed to implement the EU regulations on the occupational exposure to electromagnetic fields, including those generated by Magnetic Resonance Imaging (MRI) units. Waiting for the revision of the exposure limits proposed by the EU Directive taking into account results from new studies and evolution of knowledge, the time-weighted values of static magnetic field proposed by the Italian Ministry of Health (D.M 02/08/91) still survive as limits for worker's exposure. The comparison between the proposed thresholds and the time required to position patients allows to calculate how long the MRI staff can stay at different values of static magnetic field, i.e. the maximum workload of each worker. In order to evaluate more accurately how many time the members of MRI staff are near the magnet bore and the real value of worker's exposure to the static magnetic field during the handling of patients, a teslameter Metrolab THM1176-PDA was used. Personal exposure measurements on the radiologists and the radiographers who worked on a 3 T GE Healthcare Discovery 750 MR were carried out during the positioning of self-sufficient and collaborative patients. The sensor was worn at the chest level on the side that was nearest to the magnet bore. Results show wide variations occurring between individual working procedures concerning the handling of patients, especially during the initial position phase. The mean values of the time spent by radiographers inside the magnet room (B > 0.5 mT) to place the patient and to take him outside at the end of the exam were respectively 220 and 127 seconds. The mean value of the time spent by radiologists was 162 seconds when they had to insert a peripheral

  1. Standardized quantitative measurements of wrist cartilage in healthy humans using 3T magnetic resonance imaging

    PubMed Central

    Zink, Jean-Vincent; Souteyrand, Philippe; Guis, Sandrine; Chagnaud, Christophe; Fur, Yann Le; Militianu, Daniela; Mattei, Jean-Pierre; Rozenbaum, Michael; Rosner, Itzhak; Guye, Maxime; Bernard, Monique; Bendahan, David

    2015-01-01

    AIM: To quantify the wrist cartilage cross-sectional area in humans from a 3D magnetic resonance imaging (MRI) dataset and to assess the corresponding reproducibility. METHODS: The study was conducted in 14 healthy volunteers (6 females and 8 males) between 30 and 58 years old and devoid of articular pain. Subjects were asked to lie down in the supine position with the right hand positioned above the pelvic region on top of a home-built rigid platform attached to the scanner bed. The wrist was wrapped with a flexible surface coil. MRI investigations were performed at 3T (Verio-Siemens) using volume interpolated breath hold examination (VIBE) and dual echo steady state (DESS) MRI sequences. Cartilage cross sectional area (CSA) was measured on a slice of interest selected from a 3D dataset of the entire carpus and metacarpal-phalangeal areas on the basis of anatomical criteria using conventional image processing radiology software. Cartilage cross-sectional areas between opposite bones in the carpal region were manually selected and quantified using a thresholding method. RESULTS: Cartilage CSA measurements performed on a selected predefined slice were 292.4 ± 39 mm2 using the VIBE sequence and slightly lower, 270.4 ± 50.6 mm2, with the DESS sequence. The inter (14.1%) and intra (2.4%) subject variability was similar for both MRI methods. The coefficients of variation computed for the repeated measurements were also comparable for the VIBE (2.4%) and the DESS (4.8%) sequences. The carpus length averaged over the group was 37.5 ± 2.8 mm with a 7.45% between-subjects coefficient of variation. Of note, wrist cartilage CSA measured with either the VIBE or the DESS sequences was linearly related to the carpal bone length. The variability between subjects was significantly reduced to 8.4% when the CSA was normalized with respect to the carpal bone length. CONCLUSION: The ratio between wrist cartilage CSA and carpal bone length is a highly reproducible standardized

  2. Window frame or superferric magnet design for low B(3T) heavy ion storage ring study

    NASA Astrophysics Data System (ADS)

    Danby, G.; Devito, B.; Jackson, J.; Keohane, G.; Lee, Y.; Phillips, R.; Plate, S.; Repeta, L.; Skaritka, J.; Smith, L.

    Double magnets share common laminations without magnetic coupling. Single layer coils of rectangular conductor are dry wound on extruded bore tubes. Magnet construction requires no molding or prestress. Absence of superconducting (SC) magnetization fields in the aperture results in very large dynamic range. The coil is wound continuously across the modplane to give unusually large dynamic aperture. Above approx. 2.2 T saturation is corrected by simple sextupole windings with no inductive coupling to the dipole. Ultrastable design requires no internal quench protection. A quadrupole pair of novel design gives excellent field quality to B . 2 T without corrections, with no SC magnetization. Experience shows magnets are accurate enough for the assembly to take place at its final location. No training is required. Test procedures (measurements with search coils or with the beam) and cooldown properties are discussed.

  3. Hydroxytyrosol promotes mitochondrial biogenesis and mitochondrial function in 3T3-L1 adipocytes.

    PubMed

    Hao, Jiejie; Shen, Weili; Yu, Guangli; Jia, Haiqun; Li, Xuesen; Feng, Zhihui; Wang, Ying; Weber, Peter; Wertz, Karin; Sharman, Edward; Liu, Jiankang

    2010-07-01

    Hydroxytyrosol (HT) in extra-virgin olive oil is considered one of the most important polyphenolic compounds responsible for the health benefits of the Mediterranean diet for lowering incidence of cardiovascular disease, the most common and most serious complication of diabetes. We propose that HT may prevent these diseases by a stimulation of mitochondrial biogenesis that leads to enhancement of mitochondrial function and cellular defense systems. In the present study, we investigated effects of HT that stimulate mitochondrial biogenesis and promote mitochondrial function in 3T3-L1 adipocytes. HT over the concentration range of 0.1-10 micromol/L stimulated the promoter transcriptional activation and protein expression of peroxisome proliferator-activated receptor (PPAR) coactivator 1 alpha (PPARGC1 alpha, the central factor for mitochondrial biogenesis) and its downstream targets; these included nuclear respiration factors 1 and 2 and mitochondrial transcription factor A, which leads to an increase in mitochondrial DNA (mtDNA) and in the number of mitochondria. Knockdown of Ppargc1 alpha by siRNA blocked HT's stimulating effect on Complex I expression and mtDNA copy number. The HT treatment resulted in an enhancement of mitochondrial function, including an increase in activity and protein expression of Mitochondrial Complexes I, II, III and V; increased oxygen consumption; and a decrease in free fatty acid contents in the adipocytes. The mechanistic study of the PPARGC1 alpha activation signaling pathway demonstrated that HT is an activator of 5'AMP-activated protein kinase and also up-regulates gene expression of PPAR alpha, CPT-1 and PPAR gamma. These data suggest that HT is able to promote mitochondrial function by stimulating mitochondrial biogenesis. PMID:19576748

  4. High-resolution In Vivo Manual Segmentation Protocol for Human Hippocampal Subfields Using 3T Magnetic Resonance Imaging.

    PubMed

    Winterburn, Julie; Pruessner, Jens C; Sofia, Chavez; Schira, Mark M; Lobaugh, Nancy J; Voineskos, Aristotle N; Chakravarty, M Mallar

    2015-01-01

    The human hippocampus has been broadly studied in the context of memory and normal brain function and its role in different neuropsychiatric disorders has been heavily studied. While many imaging studies treat the hippocampus as a single unitary neuroanatomical structure, it is, in fact, composed of several subfields that have a complex three-dimensional geometry. As such, it is known that these subfields perform specialized functions and are differentially affected through the course of different disease states. Magnetic resonance (MR) imaging can be used as a powerful tool to interrogate the morphology of the hippocampus and its subfields. Many groups use advanced imaging software and hardware (>3T) to image the subfields; however this type of technology may not be readily available in most research and clinical imaging centers. To address this need, this manuscript provides a detailed step-by-step protocol for segmenting the full anterior-posterior length of the hippocampus and its subfields: cornu ammonis (CA) 1, CA2/CA3, CA4/dentate gyrus (DG), strata radiatum/lacunosum/moleculare (SR/SL/SM), and subiculum. This protocol has been applied to five subjects (3F, 2M; age 29-57, avg. 37). Protocol reliability is assessed by resegmenting either the right or left hippocampus of each subject and computing the overlap using the Dice's kappa metric. Mean Dice's kappa (range) across the five subjects are: whole hippocampus, 0.91 (0.90-0.92); CA1, 0.78 (0.77-0.79); CA2/CA3, 0.64 (0.56-0.73); CA4/dentate gyrus, 0.83 (0.81-0.85); strata radiatum/lacunosum/moleculare, 0.71 (0.68-0.73); and subiculum 0.75 (0.72-0.78). The segmentation protocol presented here provides other laboratories with a reliable method to study the hippocampus and hippocampal subfields in vivo using commonly available MR tools.

  5. High-resolution In Vivo Manual Segmentation Protocol for Human Hippocampal Subfields Using 3T Magnetic Resonance Imaging.

    PubMed

    Winterburn, Julie; Pruessner, Jens C; Sofia, Chavez; Schira, Mark M; Lobaugh, Nancy J; Voineskos, Aristotle N; Chakravarty, M Mallar

    2015-01-01

    The human hippocampus has been broadly studied in the context of memory and normal brain function and its role in different neuropsychiatric disorders has been heavily studied. While many imaging studies treat the hippocampus as a single unitary neuroanatomical structure, it is, in fact, composed of several subfields that have a complex three-dimensional geometry. As such, it is known that these subfields perform specialized functions and are differentially affected through the course of different disease states. Magnetic resonance (MR) imaging can be used as a powerful tool to interrogate the morphology of the hippocampus and its subfields. Many groups use advanced imaging software and hardware (>3T) to image the subfields; however this type of technology may not be readily available in most research and clinical imaging centers. To address this need, this manuscript provides a detailed step-by-step protocol for segmenting the full anterior-posterior length of the hippocampus and its subfields: cornu ammonis (CA) 1, CA2/CA3, CA4/dentate gyrus (DG), strata radiatum/lacunosum/moleculare (SR/SL/SM), and subiculum. This protocol has been applied to five subjects (3F, 2M; age 29-57, avg. 37). Protocol reliability is assessed by resegmenting either the right or left hippocampus of each subject and computing the overlap using the Dice's kappa metric. Mean Dice's kappa (range) across the five subjects are: whole hippocampus, 0.91 (0.90-0.92); CA1, 0.78 (0.77-0.79); CA2/CA3, 0.64 (0.56-0.73); CA4/dentate gyrus, 0.83 (0.81-0.85); strata radiatum/lacunosum/moleculare, 0.71 (0.68-0.73); and subiculum 0.75 (0.72-0.78). The segmentation protocol presented here provides other laboratories with a reliable method to study the hippocampus and hippocampal subfields in vivo using commonly available MR tools. PMID:26575133

  6. Note: Spectral motional Stark effect diagnostic for measurement of magnetic fields below 0.3 T

    NASA Astrophysics Data System (ADS)

    Lizunov, A.; Donin, A.; Savkin, V.

    2013-08-01

    The paper reports on development of the spectral motional Stark effect (MSE) diagnostic in the midplane of the gas dynamic trap (GDT) linear system for magnetic confinement of anisotropic hot-ion plasma. The axially symmetric GDT vacuum magnetic field has a minimum value in the midplane, which varies from 0.2 to 0.35 T in different regimes of operation. Buildup of 15 keV ion population generates a diamagnetic reduction of magnetic field in the plasma core of up to 30% in the maximum density region, as measured by the existing eight-line MSE diagnostic. Commissioning of the midplane MSE provided first direct measurements of diamagnetic modifications in the minimum magnetic field GDT section, a necessary complement to the understanding of equilibrium and self-organization of high-β plasmas in GDT. Making use of the stable short-pulse diagnostic beam and calibration of the apparent spectral width of beam emission lines allow for the measurement of the plasma magnetic field of 0.29 ± 0.007 T with the integration time of 200 μs.

  7. High resolution neurography of the lumbosacral plexus on 3T magneteic resonance imaging.

    PubMed

    Cejas, C; Escobar, I; Serra, M; Barroso, F

    2015-01-01

    Magnetic resonance neurography is a technique that complements clinical and electrophysiological study of the peripheral nerves and brachial and lumbosacral plexuses. Numerous focal processes (inflammatory, traumatic, primary tumors, secondary tumors) and diffuse processes (diabetic polyneuropathy, chronic idiopathic demyelinating polyneuropathy due to amyloidosis or Charcot-Marie-Tooth disease) can involve the lumbosacral plexus. This article reviews the anatomy of the lumbosacral plexus, describes the technique for neurography of the plexus at our institution, and shows the diverse diseases that affect it.

  8. [High resolution 3T magnetic resonance neurography of the peroneal nerve].

    PubMed

    Pineda, D; Barroso, F; Cháves, H; Cejas, C

    2014-01-01

    Peroneal neuropathy is the most common mononeuropathy of the lower limbs. The causes of peroneal neuropathy include trauma, tumors of the nerve and nerve sheath, entrapment, and others like perineurioma, fibromatosis, lymphoma, and intraneural and externeural ganglia. The diagnosis is based on clinical manifestations and electrophysiological studies. Nowadays, however, magnetic resonance (MR) neurography is a complementary diagnostic technique that can help determine the location and cause of peroneal neuropathy. In this article, we describe the MR anatomy of the peroneal nerve, its relations, and the muscles it innervates. We also discuss the clinical and electrophysiological manifestations of peroneal neuropathy, describe the technical parameters used at our institution, and illustrate the MR appearance of various diseases that involve the peroneal nerve.

  9. Long term effects of cocaine on the heart assessed by cardiovascular magnetic resonance at 3T

    PubMed Central

    2014-01-01

    Background Cocaine is an addictive, sympathomimetic drug with potentially lethal effects. The prevalence and features of cocaine cardiotoxicity are not well known. We aimed to assess these effects using a comprehensive cardiovascular magnetic resonance (CMR) protocol in a large group of asymptomatic cocaine users. Methods Consecutive (n = 94, 81 males, 36.6 ±7 years), non-selected, cocaine abusers were recruited and had a medical history, examination, ECG, blood test and CMR. The CMR study included measurement of left and right ventricular (LV, RV) dimensions and ejection fraction (EF), sequences for detection of myocardial oedema and late gadolinium enhancement (LGE). Images were compared to a cohort of healthy controls. Results Years of regular cocaine use were 13.9 ± 9. When compared to the age-matched healthy cohort, the cocaine abusers had increased LV end-systolic volume, LV mass index and RV end-systolic volume, with decreased LVEF and RVEF. No subject had myocardial oedema, but 30% had myocardial LGE indicating myocardial damage. Conclusions CMR detected cardiovascular disease in 71% of this cohort of consecutive asymptomatic cocaine abusers and mean duration of abuse was related to probability of LV systolic dysfunction. PMID:24758161

  10. 3T magnetic resonance neurography of pudendal nerve with cadaveric dissection correlation

    PubMed Central

    Chhabra, Avneesh; McKenna, Courtney A; Wadhwa, Vibhor; Thawait, Gaurav K; Carrino, John A; Lees, Gary P; Dellon, A Lee

    2016-01-01

    AIM To evaluate the pudendal nerve segments that could be identified on magnetic resonance neurography (MRN) before and after surgical marking of different nerve segments. METHODS The hypothesis for this study was that pudendal nerve and its branches would be more easily seen after the surgical nerve marking. Institutional board approval was obtained. One male and one female cadaver pelvis were obtained from the anatomy board and were scanned using 3 Tesla MRI scanner using MR neurography sequences. All possible pudendal nerve branches were identified. The cadavers were then sent to the autopsy lab and were surgically dissected by a peripheral nerve surgeon and an anatomist to identify the pudendal nerve branches. Radiological markers were placed along the course of the pudendal nerve and its branches. The cadavers were then closed and rescanned using the same MRN protocol as the pre-marking scan. The remaining pudendal nerve branches were attempted to be identified using the radiological markers. All scans were read by an experienced musculoskeletal radiologist. RESULTS The pre-marking MR Neurography scans clearly showed the pudendal nerve at its exit from the lumbosacral plexus in the sciatic notch, at the level of the ischial spine and in the Alcock’s Canal in both cadavers. Additionally, the right hemorrhoidal branch could be identified in the male pelvis cadaver. The perineal and distal genital branches could not be identified. On post-marking scans, the markers were used as identifiable structures. The location of the perineal branch, the hemorroidal branch and the dorsal nerve to penis (in male cadaver)/clitoris (in female cadaver) could be seen. However, the visualization of these branches was suboptimal. The contralateral corresponding nerves were poorly seen despite marking on the surgical side. The nerve was best seen on axial T1W and T2W SPAIR images. The proximal segment could be seen well on 3D DW PSIF sequence. T2W SPACE was not very useful in

  11. Quantifiable Imaging Biomarkers for Evaluation of the Posterior Cruciate Ligament Using 3-T Magnetic Resonance Imaging

    PubMed Central

    Wilson, Katharine J.; Surowiec, Rachel K.; Ho, Charles P.; Devitt, Brian M.; Fripp, Jurgen; Smith, W. Sean; Spiegl, Ulrich J.; Dornan, Grant J.; LaPrade, Robert F.

    2016-01-01

    Background: Quantitative magnetic resonance imaging (MRI) techniques, such as T2 and T2 star (T2*) mapping, have been used to evaluate ligamentous tissue in vitro and to identify significant changes in structural integrity of a healing ligament. These studies lay the foundation for a clinical study that uses quantitative mapping to evaluate ligaments in vivo, particularly the posterior cruciate ligament (PCL). To establish quantitative mapping as a clinical tool for identifying and evaluating chronic or acute PCL injuries, T2 and T2* values first must be determined for an asymptomatic population. Purpose: To quantify T2 and T2* mapping properties, including texture variables (entropy, variance, contrast, homogeneity), of the PCL in an asymptomatic population. It was hypothesized that biomarker values would be consistent throughout the ligament, as measured across 3 clinically relevant subregions (proximal, middle, and distal thirds) in the asymptomatic cohort. Study Design: Cross-sectional study; Level of evidence, 4. Methods: Unilateral knee MRI scans were acquired for 25 asymptomatic subjects with a 3.0-T MRI system using T2 and T2* mapping sequences in the sagittal plane. The PCL was manually segmented and divided into thirds (proximal, middle, and distal). Summary statistics for T2 and T2* values were calculated. Intra- and interrater reliability was assessed across 3 raters to 2 time points. Results: The asymptomatic PCL cohort had mean T2 values of 36.7, 29.2, and 29.6 ms in the distal, middle, and proximal regions, respectively. The distal PCL exhibited significantly higher mean, variance, and contrast and lower homogeneity of T2 values than the middle and proximal subregions (P < .05). T2* results exhibited substantial positive skew and were therefore presented as median and quartile (Q) values. Median T2* values were 7.3 ms (Q1-Q3, 6.8-8.9 ms), 7.3 ms (Q1-Q3, 7.0-8.5 ms), and 7.3 ms (Q1-Q3, 6.4-8.2 ms) in the distal, middle, and proximal subregions

  12. Significant Artifact Reduction at 1.5T and 3T MRI by the Use of a Cochlear Implant with Removable Magnet: An Experimental Human Cadaver Study

    PubMed Central

    Wagner, Franca; Wimmer, Wilhelm; Leidolt, Lars; Vischer, Mattheus; Weder, Stefan; Wiest, Roland; Mantokoudis, Georgios; Caversaccio, Marco D.

    2015-01-01

    Objective Cochlear implants (CIs) are standard treatment for postlingually deafened individuals and prelingually deafened children. This human cadaver study evaluated diagnostic usefulness, image quality and artifacts in 1.5T and 3T magnetic resonance (MR) brain scans after CI with a removable magnet. Methods Three criteria (diagnostic usefulness, image quality, artifacts) were assessed at 1.5T and 3T in five cadaver heads with CI. The brain magnetic resonance scans were performed with and without the magnet in situ. The criteria were analyzed by two blinded neuroradiologists, with focus on image distortion and limitation of the diagnostic value of the acquired MR images. Results MR images with the magnet in situ were all compromised by artifacts caused by the CI. After removal of the magnet, MR scans showed an unequivocal artifact reduction with significant improvement of the image quality and diagnostic usefulness, both at 1.5T and 3T. Visibility of the brain stem, cerebellopontine angle, and parieto-occipital lobe ipsilateral to the CI increased significantly after magnet removal. Conclusions The results indicate the possible advantages for 1.5T and 3T MR scanning of the brain in CI carriers with removable magnets. Our findings support use of CIs with removable magnets, especially in patients with chronic intracranial pathologies. PMID:26200775

  13. Improving Bladder Cancer Imaging Using 3T Functional Dynamic Contrast-Enhanced MRI

    PubMed Central

    Nguyen, Huyen T.; Pohar, Kamal S.; Jia, Guang; Shah, Zarine K.; Mortazavi, Amir; Zynger, Debra L.; Wei, Lai; Clark, Daniel; Yang, Xiangyu; Knopp, Michael V.

    2015-01-01

    Objectives To assess the capability of T2-weighted MRI (T2W-MRI) and the additional diagnostic value of Dynamic Contrast-Enhanced MRI (DCE-MRI) using multi-transmit 3T in the localization of bladder cancer. Materials and Methods This prospective study was approved by the local Institutional Review Board. Thirty–six patients were included in the study and provided informed consent. MRI scans were performed with T2W-MRI and DCE-MRI on a 3T multi-transmit system. Two observers (with 12 and 25 years of experience) independently interpreted T2W-MRI prior to DCE-MRI data (maps of pharmacokinetic parameters) to localize bladder tumors. The pathological examination of cystectomy bladder specimens was used as a reference gold standard. The McNemar test was performed to evaluate the differences in sensitivity, specificity, and accuracy. Kappa scores were calculated to assess interobserver agreement. Results The sensitivity, specificity, and accuracy of the localization with T2W-MRI alone were 81% (29/36), 63% (5/8) and 77% (34/44) for observer 1, and 72% (26/36), 63% (5/8), and 70% (31/44) for observer 2. With additional DCE-MRI available, these values were 92% (33/36), 75% (6/8), and 89% (39/44) for observer 1, and 92% (33/36), 63% (5/8), and 86% (38/44) for observer 2. DCE-MRI significantly (P < 0.01) improved the sensitivity and accuracy for observer 2. For the twenty-three patients treated with chemotherapy, DCE-MRI also significantly (P < 0.02) improved the sensitivity and accuracy of bladder cancer localization with T2W-MRI alone for observer 2. Kappa scores were 0.63 for T2W-MRI alone, and 0.78 for additional DCE-MRI. Out of seven sub-centimeter malignant tumors, four (57%) were identified on T2W images and six (86%) on DCE maps. Out of eleven malignant tumors within the bladder wall thickening, six (55%) were found on T2W images and ten (91%) on DCE maps. Conclusions Compared to conventional T2W-MRI alone, the addition of DCE-MRI improved interobserver agreement as

  14. Functional expression of 5-HT{sub 2A} receptor in osteoblastic MC3T3-E1 cells

    SciTech Connect

    Hirai, Takao; Kaneshige, Kota; Kurosaki, Teruko; Nishio, Hiroaki

    2010-05-28

    In the previous study, we reported the gene expression for proteins related to the function of 5-hydroxytryptamine (5-HT, serotonin) and elucidated the expression patterns of 5-HT{sub 2} receptor subtypes in mouse osteoblasts. In the present study, we evaluated the possible involvement of 5-HT receptor subtypes and its inactivation system in MC3T3-E1 cells, an osteoblast cell line. DOI, a 5-HT{sub 2A} and 5-HT{sub 2C} receptor selective agonist, as well as 5-HT concentration-dependently increased proliferative activities of MC3T3-E1 cells in their premature period. This effect of 5-HT on cell proliferation were inhibited by ketanserin, a 5-HT{sub 2A} receptor specific antagonist. Moreover, both DOI-induced cell proliferation and phosphorylation of ERK1 and 2 proteins were inhibited by PD98059 and U0126, selective inhibitors of MEK in a concentration-dependent manner. Furthermore, treatment with fluoxetine, a 5-HT specific re-uptake inhibitor which inactivate the function of extracellular 5-HT, significantly increased the proliferative activities of MC3T3-E1 cells in a concentration-dependent manner. Our data indicate that 5-HT fill the role for proliferation of osteoblast cells in their premature period. Notably, 5-HT{sub 2A} receptor may be functionally expressed to regulate mechanisms underlying osteoblast cell proliferation, at least in part, through activation of ERK/MAPK pathways in MC3T3-E1 cells.

  15. Heating induced near deep brain stimulation lead electrodes during magnetic resonance imaging with a 3 T transceive volume head coil.

    PubMed

    Shrivastava, Devashish; Abosch, Aviva; Hughes, John; Goerke, Ute; DelaBarre, Lance; Visaria, Rachana; Harel, Noam; Vaughan, J Thomas

    2012-09-01

    Heating induced near deep brain stimulation (DBS) lead electrodes during magnetic resonance imaging with a 3 T transceive head coil was measured, modeled, and imaged in three cadaveric porcine heads (mean body weight = 85.47 ± 3.19 kg, mean head weight = 5.78 ± 0.32 kg). The effect of the placement of the extra-cranial portion of the DBS lead on the heating was investigated by looping the extra-cranial lead on the top, side, and back of the head, and placing it parallel to the coil's longitudinal axial direction. The heating was induced using a 641 s long turbo spin echo sequence with the mean whole head average specific absorption rate of 3.16 W kg(-1). Temperatures were measured using fluoroptic probes at the scalp, first and second electrodes from the distal lead tip, and 6 mm distal from electrode 1 (T(6 mm)). The heating was modeled using the maximum T(6 mm) and imaged using a proton resonance frequency shift-based MR thermometry method. Results showed that the heating was significantly reduced when the extra-cranial lead was placed in the longitudinal direction compared to the other placements (peak temperature change = 1.5-3.2 °C versus 5.1-24.7 °C). Thermal modeling and MR thermometry may be used together to determine the heating and improve patient safety online.

  16. Increased NIH 3T3 fibroblast functions on cell culture dishes which mimic the nanometer fibers of natural tissues

    PubMed Central

    Bhardwaj, Garima; Webster, Thomas J

    2015-01-01

    Traditional flat tissue cell culture dishes have consisted of polystyrene treated with plasma gases for growing, subculturing, and studying cell behavior in vitro. However, increasingly it has been observed that mimicking natural tissue properties (such as chemistry, three-dimensional structure, mechanical properties, etc) in vitro can lead to a better correlation of in vitro to in vivo cellular functions. The following studies compared traditional NIH 3T3 fibroblasts’ functions on XanoMatrix scaffolds to standard tissue culture polystyrene. Results found significantly greater fibroblast adhesion and proliferation on XanoMatrix cell culture dishes which mimic the nanoscale geometry of natural tissue fibers with true, tortuous fiber beds creating a robust, consistent, and versatile growth platform. In this manner, this study supports that cell culture dishes which mimic features of natural tissues should be continually studied for a wide range of applications in which mimicking natural cellular functions are important. PMID:26345155

  17. Dense, shape‐optimized posterior 32‐channel coil for submillimeter functional imaging of visual cortex at 3T

    PubMed Central

    Grigorov, Filip; van der Kouwe, Andre J.; Wald, Lawrence L.; Keil, Boris

    2015-01-01

    Purpose Functional neuroimaging of small cortical patches such as columns is essential for testing computational models of vision, but imaging from cortical columns at conventional 3T fields is exceedingly difficult. By targeting the visual cortex exclusively, we tested whether combined optimization of shape, coil placement, and electronics would yield the necessary gains in signal‐to‐noise ratio (SNR) for submillimeter visual cortex functional MRI (fMRI). Method We optimized the shape of the housing to a population‐averaged atlas. The shape was comfortable without cushions and resulted in the maximally proximal placement of the coil elements. By using small wire loops with the least number of solder joints, we were able to maximize the Q factor of the individual elements. Finally, by planning the placement of the coils using the brain atlas, we were able to target the arrangement of the coil elements to the extent of the visual cortex. Results The combined optimizations led to as much as two‐fold SNR gain compared with a whole‐head 32‐channel coil. This gain was reflected in temporal SNR as well and enabled fMRI mapping at 0.75 mm resolutions using a conventional GRAPPA‐accelerated gradient echo echo planar imaging. Conclusion Integrated optimization of shape, electronics, and element placement can lead to large gains in SNR and empower submillimeter fMRI at 3T. Magn Reson Med 76:321–328, 2016. © 2015 Wiley Periodicals, Inc. PMID:26218835

  18. A Novel Regulatory Function of Sweet Taste-Sensing Receptor in Adipogenic Differentiation of 3T3-L1 Cells

    PubMed Central

    Masubuchi, Yosuke; Nakagawa, Yuko; Ma, Jinhui; Sasaki, Tsutomu; Kitamura, Tadahiro; Yamamoto, Yoritsuna; Kurose, Hitoshi; Kojima, Itaru; Shibata, Hiroshi

    2013-01-01

    Background Sweet taste receptor is expressed not only in taste buds but also in nongustatory organs such as enteroendocrine cells and pancreatic beta-cells, and may play more extensive physiological roles in energy metabolism. Here we examined the expression and function of the sweet taste receptor in 3T3-L1 cells. Methodology/Principal Findings In undifferentiated preadipocytes, both T1R2 and T1R3 were expressed very weakly, whereas the expression of T1R3 but not T1R2 was markedly up-regulated upon induction of differentiation (by 83.0 and 3.8-fold, respectively at Day 6). The α subunits of Gs (Gαs) and G14 (Gα14) but not gustducin were expressed throughout the differentiation process. The addition of sucralose or saccharin during the first 48 hours of differentiation considerably reduced the expression of peroxisome proliferator activated receptor γ (PPARγ and CCAAT/enhancer-binding protein α (C/EBPα at Day 2, the expression of aP2 at Day 4 and triglyceride accumulation at Day 6. These anti-adipogenic effects were attenuated by short hairpin RNA-mediated gene-silencing of T1R3. In addition, overexpression of the dominant-negative mutant of Gαs but not YM-254890, an inhibitor of Gα14, impeded the effects of sweeteners, suggesting a possible coupling of Gs with the putative sweet taste-sensing receptor. In agreement, sucralose and saccharin increased the cyclic AMP concentration in differentiating 3T3-L1 cells and also in HEK293 cells heterologously expressing T1R3. Furthermore, the anti-adipogenic effects of sweeteners were mimicked by Gs activation with cholera toxin but not by adenylate cyclase activation with forskolin, whereas small interfering RNA-mediated knockdown of Gαs had the opposite effects. Conclusions 3T3-L1 cells express a functional sweet taste-sensing receptor presumably as a T1R3 homomer, which mediates the anti-adipogenic signal by a Gs-dependent but cAMP-independent mechanism. PMID:23336004

  19. The effect of cultureware surfaces on functional and structural components of differentiated 3T3-L1 preadipocytes.

    PubMed

    Pavlikova, Nela; Weiszenstein, Martin; Pala, Jan; Halada, Petr; Seda, Ondrej; Elkalaf, Moustafa; Trnka, Jan; Kovar, Jan; Polak, Jan

    2015-12-01

    Experiments using cultured primary cells or cell lines are a routine in vitro approach used across multiple biological disciplines, However, the structural and functional influences of various cultureware materials on cultured cells is not clearly understood. Surface treatments of cultureware have proven to have profound effects on cell viability and proliferation. In this study, we investigated the impact of polystyrene and fluorocarbon cultureware dishes on the proteomic profile of differentiated 3T3-L1 preadipocytes. After expansion and differentiation of cells on appropriate cultureware dishes, cell lysates were separated using two-dimensional gel electrophoresis and proteins were visualized with Coomassie blue staining. Spots with the highest differential expression between the two culture conditions were subsequently analyzed using matrix-assisted laser desorption/ionization mass spectrometry and the identified proteins were subjected to pathway analysis. We observed that 43% of all spots were differentially expressed depending on the cultureware. Pathway analysis revealed that glucose metabolism, mitochondrial structure and cell differentiation, represented by 14-3-3 protein-mediated signaling and the mitochondrial inner membrane organizing system (MINOS), were significantly affected by cultureware material. These results indicate that cultureware material can have a profound effect on key adipocyte functional pathways. These effects modifications of the cells should be reflected in the design of in vitro experiments and interpretation of their results.

  20. Functional Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Voos, Avery; Pelphrey, Kevin

    2013-01-01

    Functional magnetic resonance imaging (fMRI), with its excellent spatial resolution and ability to visualize networks of neuroanatomical structures involved in complex information processing, has become the dominant technique for the study of brain function and its development. The accessibility of in-vivo pediatric brain-imaging techniques…

  1. Initial assessment of the performance of an 0.3 T permanent magnet in whole body NMR imaging.

    PubMed

    Keeler, E K; Giambalvo, A; Smith, S D; Negendank, W

    1983-01-01

    An 0.3 Tesla permanent magnet was constructed and incorporated into a complete whole body NMR imager. Axial, sagittal and coronal images from human subjects were obtained using a two-dimensional Fourier Transform analysis of selected planes 8 mm thick, combined with an efficient multislice technique that produces sections centered 12 mm apart. Images were obtained based on inversion recovery and spin echo modes. The permanent magnetic field is uniform to 10 ppm over 38 cm. The magnet requires no special maintenance and has an extremely small fringe field. The magnet design, with its field vertical to the long axis of the subject, permits use of a solenoidal radiofrequency receiving coil for optimal signal-to-noise ratio. Images were shown that are of high quality and produced under conditions simulating those necessary for efficient patient throughout in a clinical setting. Many of the unique features of NMR imaging, such as ability to directly obtain axial, sagittal and coronal projections, the variety of imaging modes, the natural sources of contrast, and the ability to visualize clearly medium and large blood vessels, were demonstrated.

  2. Functional magnetic microspheres

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (Inventor); Rembaum, Alan (Inventor); Landel, Robert F. (Inventor)

    1981-01-01

    Functional magnetic particles are formed by dissolving a mucopolysaccharide such as chitosan in acidified aqueous solution containing a mixture of ferrous chloride and ferric chloride. As the pH of the solution is raised magnetite is formed in situ in the solution by raising the pH. The dissolved chitosan is a polyelectrolyte and forms micelles surrounding the granules at pH of 8-9. The chitosan precipitates on the granules to form microspheres containing the magnetic granules. On addition of the microspheres to waste aqueous streams containing dissolved ions, the hydroxyl and amine functionality of the chitosan forms chelates binding heavy metal cations such as lead, copper, and mercury and the chelates in turn bind anions such as nitrate, fluoride, phosphate and borate.

  3. Effects of Berberine on Adipose Tissues and Kidney Function in 3T3-L1 Cells and Spontaneously Hypertensive Rats.

    PubMed

    Kishimoto, Aya; Dong, Shi-Fen; Negishi, Hiroko; Yasui, Naomi; Sun, Jian-Ning; Ikeda, Katsumi

    2015-09-01

    We aimed to investigate the effect of berberine on adipose tissues, as well as its effect on renal injury in 3T3-L1 cells and spontaneously hypertensive rats. 3T3-L1 cells were cultured and treated with berberine (5-20 pM) from days 3 to 8. Berberine added to the cultured medium could significantly down-regulate transcription factors, including CCAAT/enhancer binding protein β, CCAAT/enhancer binding protein a, and peroxisome pro liferator-activated receptor y, and suppress peroxisome proliferator-activated receptor target genes, such as adipocyte fatty acid binding protein and fatty acid synthase, and inhibit 3T3-Ll fibroblast differentiation to adipocytes. Male spontaneously hypertensive rats received either 150 mg/day of berberine or saline orally for 8 weeks. Compared with the control, berberine-treated rats exhibited significant reductions in body weight gain (p < 0.05), as well as retroperitoneal and mesenteric adipose tissues (p < 0.05). Berberine-treated rats significantly decreased urinary albumin excretion, a marker of renal injury (p < 0.05). Long-term treatment with berberine decreased the adipose tissues weight and attenuated renal injury in spontaneously hypertensive rats. Based on these results, berberine has an important role in regulating adipose tissues. These results suggest the protective effect of berberine on metabolic syndrome related diseases, such as renal injury.

  4. MO-G-18C-07: Improving T2 Determination and Quantification of Lipid Methylene Protons in Proton Magnetic Resonance Spectroscopy at 3 T

    SciTech Connect

    Breitkreutz, D.; Fallone, B. G.; Yahya, A.

    2014-06-15

    Purpose: To improve proton magnetic resonance spectroscopy (MRS) transverse relaxation (T{sub 2}) determination and quantification of lipid methylene chain (1.3 ppm) protons by rewinding their J-coupling evolution. Methods: MRS experiments were performed on four lipid phantoms, namely, almond, corn, sunflower and oleic acid, using a 3 T Philips MRI scanner with a transmit/receive birdcage head coil. Two PRESS (Point RESolved Spectroscopy) pulse sequences were used. The first PRESS sequence employed standard bandwidth (BW) (∼550 Hz) RF (radiofrequency) refocussing pulses, while the second used refocussing pulses of narrow BW (∼50 Hz) designed to rewind J-coupling evolution of the methylene protons in the voxel of interest. Signal was acquired with each sequence from a 5×5×5 mm{sup 3} voxel, with a repetition time (TR) of 3000 ms, and with echo times (TE) of 100 to 200 ms in steps of 20 ms. 2048 sample points were measured with a 2000 Hz sampling bandwidth. Additionally, 30 mm outer volume suppression slabs were used to suppress signal outside the voxel of interest. The frequency of the RF pulses was set to that of the methylene resonance. Methylene peak areas were calculated and fitted in MATLAB to a monexponentially decaying function of the form M{sub 0}exp(-TE/T{sub 2}), where M{sub 0} is the extrapolated area when TE = 0 ms and yields a measure of concentration. Results: The determined values of M{sub 0} and T{sub 2} increased for all fatty acids when using the PRESS sequence with narrow BW refocussing pulses. M{sub 0} and T{sub 2} values increased by an average amount (over all the phantoms) of 31% and 14%, respectively. Conclusion: This investigation has demonstrated that J-coupling interactions of lipid methylene protons causes non-negligible signal losses which, if not accounted for, Result in underestimations of their levels and T{sub 2} values when performing MRS measurements. Funded by the Natural Sciences and Engineering Research Council of Canada

  5. Functional magnetic resonance imaging.

    PubMed

    Buchbinder, Bradley R

    2016-01-01

    Functional magnetic resonance imaging (fMRI) maps the spatiotemporal distribution of neural activity in the brain under varying cognitive conditions. Since its inception in 1991, blood oxygen level-dependent (BOLD) fMRI has rapidly become a vital methodology in basic and applied neuroscience research. In the clinical realm, it has become an established tool for presurgical functional brain mapping. This chapter has three principal aims. First, we review key physiologic, biophysical, and methodologic principles that underlie BOLD fMRI, regardless of its particular area of application. These principles inform a nuanced interpretation of the BOLD fMRI signal, along with its neurophysiologic significance and pitfalls. Second, we illustrate the clinical application of task-based fMRI to presurgical motor, language, and memory mapping in patients with lesions near eloquent brain areas. Integration of BOLD fMRI and diffusion tensor white-matter tractography provides a road map for presurgical planning and intraoperative navigation that helps to maximize the extent of lesion resection while minimizing the risk of postoperative neurologic deficits. Finally, we highlight several basic principles of resting-state fMRI and its emerging translational clinical applications. Resting-state fMRI represents an important paradigm shift, focusing attention on functional connectivity within intrinsic cognitive networks. PMID:27432660

  6. Functional magnetic resonance imaging.

    PubMed

    Buchbinder, Bradley R

    2016-01-01

    Functional magnetic resonance imaging (fMRI) maps the spatiotemporal distribution of neural activity in the brain under varying cognitive conditions. Since its inception in 1991, blood oxygen level-dependent (BOLD) fMRI has rapidly become a vital methodology in basic and applied neuroscience research. In the clinical realm, it has become an established tool for presurgical functional brain mapping. This chapter has three principal aims. First, we review key physiologic, biophysical, and methodologic principles that underlie BOLD fMRI, regardless of its particular area of application. These principles inform a nuanced interpretation of the BOLD fMRI signal, along with its neurophysiologic significance and pitfalls. Second, we illustrate the clinical application of task-based fMRI to presurgical motor, language, and memory mapping in patients with lesions near eloquent brain areas. Integration of BOLD fMRI and diffusion tensor white-matter tractography provides a road map for presurgical planning and intraoperative navigation that helps to maximize the extent of lesion resection while minimizing the risk of postoperative neurologic deficits. Finally, we highlight several basic principles of resting-state fMRI and its emerging translational clinical applications. Resting-state fMRI represents an important paradigm shift, focusing attention on functional connectivity within intrinsic cognitive networks.

  7. Accuracy and Uncertainty of Asymmetric Magnetization Transfer Ratio Quantification for Amide Proton Transfer (APT) Imaging at 3T: A Monte Carlo Study

    PubMed Central

    Yuan, Jing; Zhang, Qinwei; Wang, Yi-Xiang; Wei, Juan; Zhou, Jinyuan

    2014-01-01

    Amide proton transfer (APT) imaging offers a novel and powerful MRI contrast mechanism for quantitative molecular imaging based on the principle of chemical exchange saturation transfer (CEST). Asymmetric magnetization transfer ratio (MTRasym) quantification is crucial for Z-spectrum analysis of APT imaging, but is still challenging, particularly at clinical field strength. This paper studies the accuracy and uncertainty in the quantification of MTRasym for APT imaging at 3T, by using high-order polynomial fitting of Z-spectrum through Monte Carlo simulation. Results show that polynomial fitting is a biased estimator that consistently underestimates MTRasym. For a fixed polynomial order, the accuracy of MTRasym is almost constant with regard to signal-to-noise ratio (SNR) while the uncertainty decreases exponentially with SNR. The higher order polynomial fitting increases both the accuracy and the uncertainty of MTRasym. For different APT signal intensity levels, the relative accuracy and the absolute uncertainty keep constant for a fixed polynomial order. These results indicate the limitations and pitfalls of polynomial fitting for MTRasym quantification so better quantification technique for MTRasym estimation is warranted. PMID:24110892

  8. Accuracy and uncertainty of asymmetric magnetization transfer ratio quantification for amide proton transfer (APT) imaging at 3T: a Monte Carlo study.

    PubMed

    Yuan, Jing; Zhang, Qinwei; Wang, Yi-Xiang; Wei, Juan; Zhou, Jinyuan

    2013-01-01

    Amide proton transfer (APT) imaging offers a novel and powerful MRI contrast mechanism for quantitative molecular imaging based on the principle of chemical exchange saturation transfer (CEST). Asymmetric magnetization transfer ratio (MTR(asym)) quantification is crucial for Z-spectrum analysis of APT imaging, but is still challenging, particularly at clinical field strength. This paper studies the accuracy and uncertainty in the quantification of MTR(asym) for APT imaging at 3T, by using high-order polynomial fitting of Z-spectrum through Monte Carlo simulation. Results show that polynomial fitting is a biased estimator that consistently underestimates MTR(asym). For a fixed polynomial order, the accuracy of MTR(asym) is almost constant with regard to signal-to-noise ratio (SNR) while the uncertainty decreases exponentially with SNR. The higher order polynomial fitting increases both the accuracy and the uncertainty of MTR(asym). For different APT signal intensity levels, the relative accuracy and the absolute uncertainty keep constant for a fixed polynomial order. These results indicate the limitations and pitfalls of polynomial fitting for MTR(asym) quantification so better quantification technique for MTR(asym) estimation is warranted.

  9. Enhancement of growth and osteogenic differentiation of MC3T3-E1 cells via facile surface functionalization of polylactide membrane with chitooligosaccharide based on polydopamine adhesive coating

    NASA Astrophysics Data System (ADS)

    Li, Huihua; Luo, Chuang; Luo, Binghong; Wen, Wei; Wang, Xiaoying; Ding, Shan; Zhou, Changren

    2016-01-01

    To develop a chitooligosaccharide(COS)-functionalized poly(D,L-lactide) (PDLLA) membrane to enhance growth and osteogenic differentiation of MC3T3-E1 cells, firstly a thin polydopamine (PDOPA) layer was adhered to the PDLLA membrane via the self-polymerization and strong adhesion behavior of dopamine. Subsequently, COS was immobilized covalently on the resultant PDLLA/PDOPA composite membrane by coupling with PDOPA active coating. The successful immobilization of the PDOPA and COS was confirmed by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). Scanning electronic microscopy (SEM) and atomic force microscopy (AFM) results indicated that the surface topography and roughness of the membranes were changed, and the root mean square increased from 0.613 nm to 6.96 and 7.12 nm, respectively after coating PDOPA and COS. Water contact angle and surface energy measurements revealed that the membrane hydrophilicity was remarkably improved by surface modification. In vitro cells culture results revealed that the PDOPA- and COS-functionalized surfaces showed a significant increase in MC3T3-E1 cells adhesion, proliferation, osteogenic differentiation and alkaline phosphate activity compared to the pristine PDLLA substrate. Furthermore the COS-functionalized PDLLA membrane was more effectively at enhancing osteoblast activity than the PDOPA-functionalized PDLLA membrane.

  10. Baicalein induces CD4(+)Foxp3(+) T cells and enhances intestinal barrier function in a mouse model of food allergy.

    PubMed

    Bae, Min-Jung; Shin, Hee Soon; See, Hye-Jeong; Jung, Sun Young; Kwon, Da-Ae; Shon, Dong-Hwa

    2016-01-01

    The incidence of food allergy, which is triggered by allergen permeation of the gastrointestinal tract followed by a T-helper (Th) 2-mediated immune response, has been increasing annually worldwide. We examined the effects of baicalein (5,6,7-trihydroxyflavone), a flavonoid from Scutellaria baicalensis used in oriental herbal medicine, on regulatory T (Treg) cell induction and intestinal barrier function through the regulation of tight junctions in a mouse model of food allergy. An allergic response was induced by oral challenge with ovalbumin, and the incidence of allergic symptoms and T cell-related activity in the mesenteric lymph nodes were analyzed with and without the presence of baicalein. Our results demonstrated that the administration of baicalein ameliorated the symptoms of food allergy and attenuated serum IgE and effector T cells. However, Treg-related factors were up-regulated by baicalein. Furthermore, baicalein was shown to enhance intestinal barrier function through the regulation of tight junctions. We also found that baicalein treatment induced the differentiation of Treg cells via aryl hydrocarbon receptors (AhRs). Thus, the action of baicalein as an agonist of AhR can induce Treg differentiation and enhance barrier function, suggesting that baicalein might serve as an effective immune regulator derived from foods for the treatment of food allergy.

  11. Baicalein induces CD4+Foxp3+ T cells and enhances intestinal barrier function in a mouse model of food allergy

    PubMed Central

    Bae, Min-Jung; Shin, Hee Soon; See, Hye-Jeong; Jung, Sun Young; Kwon, Da-Ae; Shon, Dong-Hwa

    2016-01-01

    The incidence of food allergy, which is triggered by allergen permeation of the gastrointestinal tract followed by a T-helper (Th) 2-mediated immune response, has been increasing annually worldwide. We examined the effects of baicalein (5,6,7-trihydroxyflavone), a flavonoid from Scutellaria baicalensis used in oriental herbal medicine, on regulatory T (Treg) cell induction and intestinal barrier function through the regulation of tight junctions in a mouse model of food allergy. An allergic response was induced by oral challenge with ovalbumin, and the incidence of allergic symptoms and T cell-related activity in the mesenteric lymph nodes were analyzed with and without the presence of baicalein. Our results demonstrated that the administration of baicalein ameliorated the symptoms of food allergy and attenuated serum IgE and effector T cells. However, Treg-related factors were up-regulated by baicalein. Furthermore, baicalein was shown to enhance intestinal barrier function through the regulation of tight junctions. We also found that baicalein treatment induced the differentiation of Treg cells via aryl hydrocarbon receptors (AhRs). Thus, the action of baicalein as an agonist of AhR can induce Treg differentiation and enhance barrier function, suggesting that baicalein might serve as an effective immune regulator derived from foods for the treatment of food allergy. PMID:27561877

  12. Baicalein induces CD4(+)Foxp3(+) T cells and enhances intestinal barrier function in a mouse model of food allergy.

    PubMed

    Bae, Min-Jung; Shin, Hee Soon; See, Hye-Jeong; Jung, Sun Young; Kwon, Da-Ae; Shon, Dong-Hwa

    2016-01-01

    The incidence of food allergy, which is triggered by allergen permeation of the gastrointestinal tract followed by a T-helper (Th) 2-mediated immune response, has been increasing annually worldwide. We examined the effects of baicalein (5,6,7-trihydroxyflavone), a flavonoid from Scutellaria baicalensis used in oriental herbal medicine, on regulatory T (Treg) cell induction and intestinal barrier function through the regulation of tight junctions in a mouse model of food allergy. An allergic response was induced by oral challenge with ovalbumin, and the incidence of allergic symptoms and T cell-related activity in the mesenteric lymph nodes were analyzed with and without the presence of baicalein. Our results demonstrated that the administration of baicalein ameliorated the symptoms of food allergy and attenuated serum IgE and effector T cells. However, Treg-related factors were up-regulated by baicalein. Furthermore, baicalein was shown to enhance intestinal barrier function through the regulation of tight junctions. We also found that baicalein treatment induced the differentiation of Treg cells via aryl hydrocarbon receptors (AhRs). Thus, the action of baicalein as an agonist of AhR can induce Treg differentiation and enhance barrier function, suggesting that baicalein might serve as an effective immune regulator derived from foods for the treatment of food allergy. PMID:27561877

  13. Acoustic noise during functional magnetic resonance imaginga)

    PubMed Central

    Ravicz, Michael E.; Melcher, Jennifer R.; Kiang, Nelson Y.-S.

    2007-01-01

    Functional magnetic resonance imaging (fMRI) enables sites of brain activation to be localized in human subjects. For studies of the auditory system, acoustic noise generated during fMRI can interfere with assessments of this activation by introducing uncontrolled extraneous sounds. As a first step toward reducing the noise during fMRI, this paper describes the temporal and spectral characteristics of the noise present under typical fMRI study conditions for two imagers with different static magnetic field strengths. Peak noise levels were 123 and 138 dB re 20 μPa in a 1.5-tesla (T) and a 3-T imager, respectively. The noise spectrum (calculated over a 10-ms window coinciding with the highest-amplitude noise) showed a prominent maximum at 1 kHz for the 1.5-T imager (115 dB SPL) and at 1.4 kHz for the 3-T imager (131 dB SPL). The frequency content and timing of the most intense noise components indicated that the noise was primarily attributable to the readout gradients in the imaging pulse sequence. The noise persisted above background levels for 300-500 ms after gradient activity ceased, indicating that resonating structures in the imager or noise reverberating in the imager room were also factors. The gradient noise waveform was highly repeatable. In addition, the coolant pump for the imager’s permanent magnet and the room air handling system were sources of ongoing noise lower in both level and frequency than gradient coil noise. Knowledge of the sources and characteristics of the noise enabled the examination of general approaches to noise control that could be applied to reduce the unwanted noise during fMRI sessions. PMID:11051496

  14. Acoustic noise during functional magnetic resonance imaging.

    PubMed

    Ravicz, M E; Melcher, J R; Kiang, N Y

    2000-10-01

    Functional magnetic resonance imaging (fMRI) enables sites of brain activation to be localized in human subjects. For studies of the auditory system, acoustic noise generated during fMRI can interfere with assessments of this activation by introducing uncontrolled extraneous sounds. As a first step toward reducing the noise during fMRI, this paper describes the temporal and spectral characteristics of the noise present under typical fMRI study conditions for two imagers with different static magnetic field strengths. Peak noise levels were 123 and 138 dB re 20 microPa in a 1.5-tesla (T) and a 3-T imager, respectively. The noise spectrum (calculated over a 10-ms window coinciding with the highest-amplitude noise) showed a prominent maximum at 1 kHz for the 1.5-T imager (115 dB SPL) and at 1.4 kHz for the 3-T imager (131 dB SPL). The frequency content and timing of the most intense noise components indicated that the noise was primarily attributable to the readout gradients in the imaging pulse sequence. The noise persisted above background levels for 300-500 ms after gradient activity ceased, indicating that resonating structures in the imager or noise reverberating in the imager room were also factors. The gradient noise waveform was highly repeatable. In addition, the coolant pump for the imager's permanent magnet and the room air-handling system were sources of ongoing noise lower in both level and frequency than gradient coil noise. Knowledge of the sources and characteristics of the noise enabled the examination of general approaches to noise control that could be applied to reduce the unwanted noise during fMRI sessions. PMID:11051496

  15. Left Ventricular Function Evaluation on a 3T MR Scanner with Parallel RF Transmission Technique: Prospective Comparison of Cine Sequences Acquired before and after Gadolinium Injection

    PubMed Central

    Caspar, Thibault; Schultz, Anthony; Schaeffer, Mickaël; Labani, Aïssam; Jeung, Mi-Young; Jurgens, Paul Thomas; El Ghannudi, Soraya; Roy, Catherine; Ohana, Mickaël

    2016-01-01

    Objectives To compare cine MR b-TFE sequences acquired before and after gadolinium injection, on a 3T scanner with a parallel RF transmission technique in order to potentially improve scanning time efficiency when evaluating LV function. Methods 25 consecutive patients scheduled for a cardiac MRI were prospectively included and had their b-TFE cine sequences acquired before and right after gadobutrol injection. Images were assessed qualitatively (overall image quality, LV edge sharpness, artifacts and LV wall motion) and quantitatively with measurement of LVEF, LV mass, and telediastolic volume and contrast-to-noise ratio (CNR) between the myocardium and the cardiac chamber. Statistical analysis was conducted using a Bayesian paradigm. Results No difference was found before or after injection for the LVEF, LV mass and telediastolic volume evaluations. Overall image quality and CNR were significantly lower after injection (estimated coefficient cine after > cine before gadolinium: -1.75 CI = [-3.78;-0.0305], prob(coef>0) = 0% and -0.23 CI = [-0.49;0.04], prob(coef>0) = 4%) respectively), but this decrease did not affect the visual assessment of LV wall motion (cine after > cine before gadolinium: -1.46 CI = [-4.72;1.13], prob(coef>0) = 15%). Conclusions In 3T cardiac MRI acquired with parallel RF transmission technique, qualitative and quantitative assessment of LV function can reliably be performed with cine sequences acquired after gadolinium injection, despite a significant decrease in the CNR and the overall image quality. PMID:27669571

  16. Age determination of vessel wall hematoma in spontaneous cervical artery dissection: A multi-sequence 3T Cardiovascular Magnetic resonance study

    PubMed Central

    2011-01-01

    Background Previously proposed classifications for carotid plaque and cerebral parenchymal hemorrhages are used to estimate the age of hematoma according to its signal intensities on T1w and T2w MR images. Using these classifications, we systematically investigated the value of cardiovascular magnetic resonance (CMR) in determining the age of vessel wall hematoma (VWH) in patients with spontaneous cervical artery dissection (sCAD). Methods 35 consecutive patients (mean age 43.6 ± 9.8 years) with sCAD received a cervical multi-sequence 3T CMR with fat-saturated black-blood T1w-, T2w- and TOF images. Age of sCAD was defined as time between onset of symptoms (stroke, TIA or Horner's syndrome) and the CMR scan. VWH were categorized into hyperacute, acute, early subacute, late subacute and chronic based on their signal intensities on T1w- and T2w images. Results The mean age of sCAD was 2.0, 5.8, 15.7 and 58.7 days in patients with acute, early subacute, late subacute and chronic VWH as classified by CMR (p < 0.001 for trend). Agreement was moderate between VWH types in our study and the previously proposed time scheme of signal evolution for cerebral hemorrhage, Cohen's kappa 0.43 (p < 0.001). There was a strong agreement of CMR VWH classification compared to the time scheme which was proposed for carotid intraplaque hematomas with Cohen's kappa of 0.74 (p < 0.001). Conclusions Signal intensities of VWH in sCAD vary over time and multi-sequence CMR can help to determine the age of an arterial dissection. Furthermore, findings of this study suggest that the time course of carotid hematomas differs from that of cerebral hematomas. PMID:22122756

  17. A trapped magnetic field of 3 T in homogeneous, bulk MgB2 superconductors fabricated by a modified precursor infiltration and growth process

    NASA Astrophysics Data System (ADS)

    Bhagurkar, A. G.; Yamamoto, A.; Anguilano, L.; Dennis, A. R.; Durrell, J. H.; Babu, N. Hari; Cardwell, D. A.

    2016-03-01

    The wetting of boron with liquid magnesium is a critical factor in the synthesis of MgB2 bulk superconductors by the infiltration and growth (IG) process. Poor wetting characteristics can therefore result potentially in non-uniform infiltration, formation of defects in the final sample structure and poor structural homogeneity throughout the bulk material. Here we report the fabrication of near-net-shaped MgB2 bulk superconductors by a modified precursor infiltration and growth (MPIG) technique. A homogeneous bulk microstructure has subsequently been achieved via the uniform infiltration of Mg liquid by enriching pre-reacted MgB2 powder within the green precursor pellet as a wetting enhancer, leading to relatively little variation in superconducting properties across the entire bulk sample. Almost identical values of trapped magnetic field of 2.12 T have been measured at 5 K at both the top and bottom surfaces of a sample fabricated by the MPIG process, confirming the uniformity of the bulk microstructure. A maximum trapped field of 3 T has been measured at 5 K at the centre of a stack of two bulk MgB2 samples fabricated using this technique. A steady rise in trapped field was observed for this material with decreasing temperature down to 5 K without the occurrence of flux avalanches and with a relatively low field decay rate (1.5%/d). These properties are attributed to the presence of a fine distribution of residual Mg within the bulk microstructure generated by the MPIG processing technique.

  18. Magnetic Beads Enhance Adhesion of NIH 3T3 Fibroblasts: A Proof-of-Principle In Vitro Study for Implant-Mediated Long-Term Drug Delivery to the Inner Ear

    PubMed Central

    Aliuos, Pooyan; Schulze, Jennifer; Schomaker, Markus; Reuter, Günter; Stolle, Stefan R. O.; Werner, Darja; Ripken, Tammo; Lenarz, Thomas; Warnecke, Athanasia

    2016-01-01

    Introduction Long-term drug delivery to the inner ear may be achieved by functionalizing cochlear implant (CI) electrodes with cells providing neuroprotective factors. However, effective strategies in order to coat implant surfaces with cells need to be developed. Our vision is to make benefit of electromagnetic field attracting forces generated by CI electrodes to bind BDNF-secreting cells that are labelled with magnetic beads (MB) onto the electrode surfaces. Thus, the effect of MB-labelling on cell viability and BDNF production were investigated. Materials and Methods Murine NIH 3T3 fibroblasts—genetically modified to produce BDNF—were labelled with MB. Results Atomic force and bright field microscopy illustrated the internalization of MB by fibroblasts after 24 h of cultivation. Labelling cells with MB did not expose cytotoxic effects on fibroblasts and allowed adhesion on magnetic surfaces with sufficient BDNF release. Discussion Our data demonstrate a novel approach for mediating enhanced long-term adhesion of BDNF-secreting fibroblasts on model electrode surfaces for cell-based drug delivery applications in vitro and in vivo. This therapeutic strategy, once transferred to cells suitable for clinical application, may allow the biological modifications of CI surfaces with cells releasing neurotrophic or other factors of interest. PMID:26918945

  19. Magnetic Wood Achieving a Harmony between Magnetic and Woody Functions

    NASA Astrophysics Data System (ADS)

    Oka, Hideo

    Magnetic wood, which was first introduced and developed by the Oka group in 1991, achieves a good balance of both woody and magnetic functions through the active addition of magnetic characteristics to the wood itself. In addition to showing magnetic characteristics, this magnetic wood also offers a woody texture, low specific gravity, humidity control, acoustic absorption and is very easy to process.

  20. New-Generation Laser-lithographed Dual-Axis Magnetically Assisted Remote-controlled Endovascular Catheter for Interventional MR Imaging: In Vitro Multiplanar Navigation at 1.5 T and 3 T versus X-ray Fluoroscopy

    PubMed Central

    Moftakhar, Parham; Lillaney, Prasheel; Losey, Aaron D.; Cooke, Daniel L.; Martin, Alastair J.; Thorne, Bradford R. H.; Arenson, Ronald L.; Saeed, Maythem; Wilson, Mark W.

    2015-01-01

    Purpose To assess the feasibility of multiplanar vascular navigation with a new magnetically assisted remote-controlled (MARC) catheter with real-time magnetic resonance (MR) imaging at 1.5 T and 3 T and to compare it with standard x-ray guidance in simulated endovascular catheterization procedures. Materials and Methods A 1.6-mm–diameter custom clinical-grade microcatheter prototype with lithographed double-saddle coils at the distal tip was deflected with real-time MR imaging. Two inexperienced operators and two experienced operators catheterized anteroposterior (celiac, superior mesenteric, and inferior mesenteric arteries) and mediolateral (renal arteries) branch vessels in a cryogel abdominal aortic phantom. This was repeated with conventional x-ray fluoroscopy by using clinical catheters and guidewires. Mean procedure times and percentage success data were analyzed with linear mixed-effects regression. Results The MARC catheter tip was visible at 1.5 T and 3 T. Among inexperienced operators, MARC MR imaging guidance was not statistically different from x-ray guidance at 1.5 T (67% successful vessel selection turns with MR imaging vs 76% with x-ray guidance, P = .157) and at 3 T (75% successful turns with MR imaging vs 76% with x-ray guidance, P = .869). Experienced operators were more successful in catheterizing vessels with x-ray guidance (98% success within 60 seconds) than with 1.5-T (65%, P < .001) or 3-T (75%) MR imaging. Among inexperienced operators, mean procedure time was nearly equivalent by using MR imaging (31 seconds) and x-ray guidance (34 seconds, P = .436). Among experienced operators, catheterization was faster with x-ray guidance (20 seconds) compared with 1.5-T MR imaging (42 seconds, P < .001), but MARC guidance improved at 3 T (31 seconds). MARC MR imaging guidance at 3 T was not significantly different from x-ray guidance for the celiac (P = .755), superior mesenteric (P = .358), and inferior mesenteric (P = .065) arteries. Conclusion

  1. Accessory function of Kupffer cells in the antigen-specific blastogenic response of an L3T4+ T-lymphocyte clone to Listeria monocytogenes.

    PubMed Central

    Gregory, S H; Wing, E J

    1990-01-01

    The function of Kupffer cells in the development of protective immunity to infection by Listeria monocytogenes is controversial. To determine their role in antilisterial host defenses, Kupffer cells were separated from other nonparenchymal cells of the liver by centrifugation on a metrizamide gradient followed by adherence to glass or plastic. The resultant highly enriched Kupffer cell population supported the antigen-specific blastogenic response [( 3H]thymidine incorporation) of cloned L3T4+ T lymphocytes to L. monocytogenes in vitro. Blastogenesis was dependent upon the duration of the incubation period, the concentration of the antigen, and the number of Kupffer cells in culture. Maximum reactivity was greater than that observed when the same T-cell population was incubated with adherent peritoneal exudate cells and antigen under optimal conditions. The addition of antibodies specific for murine interleukin-1 beta to cocultures of Kupffer cells and T lymphocytes eliminated the antigen-stimulated incorporation of [3H]thymidine, indicating a requirement for interleukin-1. Analysis of the culture supernatants demonstrated that, in addition to interleukin-1, granulocyte-macrophage colony-stimulating factor, interleukin-6, and gamma interferon were elaborated in cocultures containing cloned T lymphocytes, Kupffer cells, and antigen. These results suggest that Kupffer cells may serve a critical role in the development of immunity to infection by L. monocytogenes in vivo. Images PMID:2114361

  2. Scaffold-free formation of a millimeter-scale multicellular spheroid with an internal cavity from magnetically levitated 3T3 cells that ingested iron oxide-containing microspheres.

    PubMed

    Lee, Joon Ho; Hur, Won

    2014-05-01

    This report describes fabrication of a millimeter-scale three-dimensional (3D) multicellular structure with a central cavity based on magnetic levitation of 3T3 cells that had ingested Fe3 O4 -containing microcapsules. Magnetically levitated cells initially formed a disc-shaped cell cluster at the air-medium interface and transformed into a spheroid (up to 2.8 mm in diameter) after 10-day incubation under a magnet. Hematoxylin-and-eosin-stained section revealed that an eosinophilic shell of cells enclosed a pale-staining core of the spheroid. Mitotic or elongated and aligned cells were found at the outer periphery of the shell, while Fe3 O4 deposits were distributed in the inner part of the shell. Surgical dissection indicated that the spheroid had a hollow interior filled with a fluid-state cell suspension. Accordingly, it was demonstrated that magnetically levitated 3T3 cells organized themselves into a tissue-like spheroid, resulting in core cell death. The spheroid can be used as a 3D tissue model and as building blocks that fused to form a more complicated structure. PMID:24254251

  3. Cytotoxic and adhesion-associated response of NIH-3T3 fibroblasts to COOH-functionalized multi-walled carbon nanotubes.

    PubMed

    Zhao, Peipei; Chen, Lusi; Shao, Han; Zhang, Yongnu; Sun, Yuqiao; Ke, Yu; Ramakrishna, Seeram; He, Liumin; Xue, Wei

    2016-02-29

    As novel, promising, man-made nanomaterials with extraordinary properties, carbon nanotubes have been attracting massive attention in regenerative medicine. However, published reports on their potential cytotoxic effects are not concordant and are even conflicting. In the current study, the cytotoxic effects of carboxyl-modified multi-walled carbon nanotubes (COOH-MWCNTs), as well as their influences on the cell adhesion of NIH-3T3 fibroblasts, were thoroughly investigated. Live/dead cell viability assay and cell counting kit-8 assay both indicated that the viability of the NIH-3T3 cells exposed to COOH-MWCNTs in the culture medium was dependent on the latter's concentration. Cell viability increased at COOH-MWCNT concentrations below 50 μg ml(-1) and then decreased with increasing concentration. Scanning electron microscopy and immunofluorescent staining of the NIH-3T3 cells revealed that the cells were well adherent to the substrate after exposure to the COOH-MWCNTs for 48 h. Western blot demonstrated that COOH-MWCNT exposure enhanced the expression of adhesion-associated proteins compared with normal cells, peaking at an intermediate concentration. Our study showed that the cytotoxicity of COOH-MWCNTs, as well as their effects on NIH-3T3 fibroblast adhesion, was dose dependent. Therefore, COOH-MWCNT concentrations in the cell culture medium should be considered in the biomedical application of COOH-MWCNTs.

  4. A proof-of-principle study of multi-site real-time functional imaging at 3T and 7T: Implementation and validation.

    PubMed

    Baecke, Sebastian; Lützkendorf, Ralf; Mallow, Johannes; Luchtmann, Michael; Tempelmann, Claus; Stadler, Jörg; Bernarding, Johannes

    2015-01-01

    Real-time functional Magnetic Resonance Imaging (rtfMRI) is used mainly for neurofeedback or for brain-computer interfaces (BCI). But multi-site rtfMRI could in fact help in the application of new interactive paradigms such as the monitoring of mutual information flow or the controlling of objects in shared virtual environments. For that reason, a previously developed framework that provided an integrated control and data analysis of rtfMRI experiments was extended to enable multi-site rtfMRI. Important new components included a data exchange platform for analyzing the data of both MR scanners independently and/or jointly. Information related to brain activation can be displayed separately or in a shared view. However, a signal calibration procedure had to be developed and integrated in order to permit the connecting of sites that had different hardware and to account for different inter-individual brain activation levels. The framework was successfully validated in a proof-of-principle study with twelve volunteers. Thus the overall concept, the calibration of grossly differing signals, and BCI functionality on each site proved to work as required. To model interactions between brains in real-time, more complex rules utilizing mutual activation patterns could easily be implemented to allow for new kinds of social fMRI experiments. PMID:25672521

  5. A proof-of-principle study of multi-site real-time functional imaging at 3T and 7T: Implementation and validation.

    PubMed

    Baecke, Sebastian; Lützkendorf, Ralf; Mallow, Johannes; Luchtmann, Michael; Tempelmann, Claus; Stadler, Jörg; Bernarding, Johannes

    2015-02-12

    Real-time functional Magnetic Resonance Imaging (rtfMRI) is used mainly for neurofeedback or for brain-computer interfaces (BCI). But multi-site rtfMRI could in fact help in the application of new interactive paradigms such as the monitoring of mutual information flow or the controlling of objects in shared virtual environments. For that reason, a previously developed framework that provided an integrated control and data analysis of rtfMRI experiments was extended to enable multi-site rtfMRI. Important new components included a data exchange platform for analyzing the data of both MR scanners independently and/or jointly. Information related to brain activation can be displayed separately or in a shared view. However, a signal calibration procedure had to be developed and integrated in order to permit the connecting of sites that had different hardware and to account for different inter-individual brain activation levels. The framework was successfully validated in a proof-of-principle study with twelve volunteers. Thus the overall concept, the calibration of grossly differing signals, and BCI functionality on each site proved to work as required. To model interactions between brains in real-time, more complex rules utilizing mutual activation patterns could easily be implemented to allow for new kinds of social fMRI experiments.

  6. Functional Magnetic Resonance Imaging Methods

    PubMed Central

    Chen, Jingyuan E.; Glover, Gary H.

    2015-01-01

    Since its inception in 1992, Functional Magnetic Resonance Imaging (fMRI) has become an indispensible tool for studying cognition in both the healthy and dysfunctional brain. FMRI monitors changes in the oxygenation of brain tissue resulting from altered metabolism consequent to a task-based evoked neural response or from spontaneous fluctuations in neural activity in the absence of conscious mentation (the “resting state”). Task-based studies have revealed neural correlates of a large number of important cognitive processes, while fMRI studies performed in the resting state have demonstrated brain-wide networks that result from brain regions with synchronized, apparently spontaneous activity. In this article, we review the methods used to acquire and analyze fMRI signals. PMID:26248581

  7. High spatial resolution time-resolved magnetic resonance angiography of lower extremity tumors at 3T: Comparison with computed tomography angiography.

    PubMed

    Wu, Gang; Jin, Teng; Li, Ting; Morelli, John; Li, Xiaoming

    2016-09-01

    The aim of this study was to compare diagnostic value of high spatial resolution time-resolved magnetic resonance angiography with interleaved stochastic trajectory (TWIST) using Gadobutrol to Computed tomography angiography (CTA) for preoperative evaluation of lower extremity tumors.This prospective study was approved by the institutional review board. Fifty consecutive patients (31 men, 19 women, age range 18-80 years, average age 42.7 years) with lower extremity tumors underwent TWIST magnetic resonance angiography (MRA) and CTA. Digital subtraction angiography was available for 8 patients. Image quality of MRA was compared with CTA by 2 radiologists according to a 4-point Likert scale. Arterial involvement by tumor was compared using kappa test between MRA and CTA. The ability to identify feeding arteries and arterio-venous fistulae (AVF) was compared using Wilcoxon signed rank test and McNemar test, respectively.Image quality of MRA and CTA was rated without a statistically significant difference (3.88 ± 0.37 vs. 3.97 ± 0.16, P = 0.135). Intramodality agreement was high for the identification of arterial invasion (kappa = 0.806 ± 0.073 for Reader 1, kappa = 0.805 ± 0.073 for Reader 2). Readers found AVF in 27 of 50 MRA cases and 14 of 50 CTA cases (P < 0.001). Mean feeding arteries identified with MRA were significantly more than that with CTA (2.08 ± 1.72 vs. 1.62 ± 1.52, P = .02).TWIST MRA is a reliable imaging modality for the assessment of lower extremity tumors. TWIST MRA is comparable to CTA for the identification of AVF and feeding arteries. PMID:27631262

  8. Abdominal MR imaging at 3T.

    PubMed

    Merkle, Elmar M; Dale, Brian M; Paulson, Erik K

    2006-02-01

    Body MR imaging at 3T is in its infancy, and should improve substantially over the next several years. Radiologists need to be aware of several limitations that are based on the laws of physics: Overall, the gain in SNR at 3T will be less than twofold (without protocol alteration) compared with a standard 1.5T MR system because of the increase in T'I'1 at ultra high field. Typically, the gain in SNR is greater in T2-weighted sequences than in TI-weighted sequences, because longer TRs allow for a more complete recovery of the longitudinal magnetization, and T2 is independent of Bo. Thus, for example, patients who are referred for an MR cholangiography may benefit from an ultrahigh-field MR examination. Chemical shift artifacts of the first kind are twice as large in ultrahigh-field MR imaging compared with standard 1.5T MR imaging. Conversely, chemical shift artifacts of the second kind do not increase in size, although the timing is altered. The increased difference in resonant frequency between water and fat at 3T also is advantageous because it allows for a better separation of the fat and water peak during MR spectroscopy, and allows better or faster fat suppression using chemical shift techniques, such as fat saturation or water excitation. Susceptibility artifacts are approximately twice as large by volume on 3T MR imaging. Although patients who are referred for a "colon" study may be challenging at ultrahigh field, the search for "gas" (eg, free air or pneumobilia) should be easier. Patients with metal implants should undergo an MR examination at 3T only if the metal-containing device specifically has been proved to be MR safe at this field strength. Usually, standing wave and conductivity effects are not seen in body imaging at a field strength of 1.5T. At 3T, these artifacts are most pronounced in pregnant women in the sec-ond and third trimester, because of the large amount of conductive amniotic fluid and the increased size of the abdomen. Therefore

  9. Functional Magnetic Resonance Imaging and Pediatric Anxiety

    ERIC Educational Resources Information Center

    Pine, Daniel S.; Guyer, Amanda E.; Leibenluft, Ellen; Peterson, Bradley S.; Gerber, Andrew

    2008-01-01

    The use of functional magnetic resonance imaging in investigating pediatric anxiety disorders is studied. Functional magnetic resonance imaging can be utilized in demonstrating parallels between the neural architecture of difference in anxiety of humans and the neural architecture of attention-orienting behavior in nonhuman primates or rodents.…

  10. Quantitative study of liver magnetic resonance spectroscopy quality at 3T using body and phased array coils with physical analysis and clinical evaluation.

    PubMed

    Xu, Li; Gu, Shiyong; Feng, Qianjin; Liang, Changhong; Xin, Sherman Xuegang

    2015-01-01

    This study aims to investigate the quality difference of short echo time (TE) breathhold 1H magnetic resonance spectroscopy (MRS) of the liver at 3.0T using the body and phased array coils, respectively. In total, 20 pairs of single-voxel proton spectra of the liver were acquired at 3.0T using the phased array and body coils as receivers. Consecutive stacks of breathhold spectra were acquired using the point resolved spectroscopy (PRESS) technique at a short TE of 30 ms and a repetition time (TR) of 1500 ms. The first spectroscopy sequence was "copied" for the second acquisition to ensure identical voxel positioning. The MRS prescan adjustments of shimming and water suppression, signal-to noise ratio (SNR), and major liver quantitative information were compared between paired spectra. Theoretical calculation of the SNR and homogeneity of the region of interest (ROI, 2 cm×2 cm×2 cm) using different coils loaded with 3D liver electromagnetic model of real human body was implemented in the theoretical analysis. The theoretical analysis showed that, inside the ROI, the SNR of the phase array coil was 2.8387 times larger than that of body coil and the homogeneity of the phase array coil and body coil was 80.10% and 93.86%, respectively. The experimental results showed excellent correlations between the paired data (all r > 0.86). Compared with the body coil group, the phased array group had slightly worse shimming effect and better SNR (all P values < .01). The discrepancy of the line width because of the different coils was approximately 0.8 Hz (0.00625 ppm). No significant differences of the major liver quantitative information of Cho/Lip2 height, Cho/Lip2 area, and lipid content were observed (all P values >0.05). The theoretical analysis and clinical experiment showed that the phased array coil was superior to the body coil with respect to 3.0T breathhold hepatic proton MRS.

  11. Glabridin Alleviates the Toxic Effects of Methylglyoxal on Osteoblastic MC3T3-E1 Cells by Increasing Expression of the Glyoxalase System and Nrf2/HO-1 Signaling and Protecting Mitochondrial Function.

    PubMed

    Choi, Eun Mi; Suh, Kwang Sik; Kim, Yu Jin; Hong, Soo Min; Park, So Yong; Chon, Suk

    2016-01-13

    Methylglyoxal (MG) contributes to the pathogenesis of age- and diabetes-associated complications. The present study investigated the effects of glabridin on MG-induced cytotoxicity in MC3T3-E1 osteoblastic cells. MC3T3-E1 cells were treated with glabridin in the presence of MG, and markers of mitochondrial function and oxidative damage were examined. Pretreatment of MC3T3-E1 osteoblastic cells with glabridin prevented MG-induced cell death, the production of intracellular reactive oxygen species and mitochondrial superoxides, cardiolipin peroxidation, and the production of inflammatory cytokines. The soluble form of receptor for advanced glycation end products (sRAGEs)/RAGE ratio increased upon MG treatment, but less so after pretreatment with glabridin, which also increased the level of reduced glutathione and the activities of glyoxalase I and heme oxygenase-1, all of which were reduced by MG. In addition, glabridin elevated the level of nuclear factor erythroid 2-related factor 2. These findings suggest that glabridin protects against MG-induced cell damage by inhibiting oxidative stress and increasing MG detoxification. Pretreatment of MC3T3-E1 osteoblastic cells with glabridin reduced MG-induced mitochondrial dysfunction. Additionally, the nitric oxide level significantly increased upon glabridin pretreatment. Together, these data show that glabridin may potentially serve to prevent the development of diabetic bone disease associated with MG-induced oxidative stress.

  12. Magnetic fields and density functional theory

    SciTech Connect

    Salsbury Jr., Freddie

    1999-02-01

    A major focus of this dissertation is the development of functionals for the magnetic susceptibility and the chemical shielding within the context of magnetic field density functional theory (BDFT). These functionals depend on the electron density in the absence of the field, which is unlike any other treatment of these responses. There have been several advances made within this theory. The first of which is the development of local density functionals for chemical shieldings and magnetic susceptibilities. There are the first such functionals ever proposed. These parameters have been studied by constructing functionals for the current density and then using the Biot-Savart equations to obtain the responses. In order to examine the advantages and disadvantages of the local functionals, they were tested numerically on some small molecules.

  13. Magnetic Anisotropy in Functionalized Bipyridyl Cryptates.

    PubMed

    Kreidt, Elisabeth; Bischof, Caroline; Platas-Iglesias, Carlos; Seitz, Michael

    2016-06-01

    The magnetic properties of molecular lanthanoid complexes are very important for a variety of scientific and technological applications, with the unique magnetic anisotropy being one of the most important features. In this context, a very rigid tris(bipyridine) cryptand was synthesized with a primary amine functionality for future bioconjugation. The magnetic anisotropy was investigated for the corresponding paramagnetic ytterbium cryptate. With the use of a combination of density functional theory calculations and lanthanoid-induced NMR shift analysis, the magnetic susceptibility tensor was determined and compared to the unfunctionalized cryptate analogue. The size and orientation of the axial and rhombic tensor components show remarkably great resilience toward the decrease of local symmetry around the metal and anion exchange in the inner coordination sphere. In addition, the functionalized ytterbium cryptate also exhibits efficient near-IR luminescence. PMID:27214575

  14. Functional Nanomaterials Useful for Magnetic Refrigeration Systems

    NASA Astrophysics Data System (ADS)

    Aslani, Amir

    Magnetic refrigeration is an emerging energy efficient and environmentally friendly refrigeration technology. The principle of magnetic refrigeration is based on the effect of varying a magnetic field on the temperature change of a magnetocaloric material (refrigerant). By applying a magnetic field, the magnetic moments of a magnetic material tend to align parallel to it, and the thermal energy released in this process heats the material. Reversibly, the magnetic moments become randomly oriented when the magnetic field is removed, and the material cools down. The heating and the cooling of a refrigerant in response to a changing magnetic field is similar to the heating and the cooling of a gaseous medium in response to an adiabatic compression and expansion in a conventional refrigeration system. One requirement to make a practical magnetic refrigerator is to have a large temperature change per unit of applied magnetic field, with sufficiently wide operating temperature. So far, no commercially viable magnetic refrigerator has been built primarily due to the low temperature change of bulk refrigerants, the added burden of hysteresis, and the system's low cooling capacity. The purpose of this dissertation is to explore magnetic refrigeration system. First, the Active Magnetic Regenerator (AMR) system built by Shir et al at the GWU's Institute for Magnetics Research (IMR) is optimized by tuning the heat transfer medium parameters and system's operating conditions. Next, by reviewing literature and works done so far on refrigerants, a number of materials that may be suitable to be used in magnetic refrigeration technology were identified. Theoretical work by Bennett et al showed an enhancement in magnetocaloric effect of magnetic nanoparticles. Research was performed on functional magnetic nanoparticles and their use in magnetic refrigeration technology. Different aspects such as the size, shape, chemical composition, structure and interaction of the nanoparticle with

  15. Tutte polynomial in functional magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    García-Castillón, Marlly V.

    2015-09-01

    Methods of graph theory are applied to the processing of functional magnetic resonance images. Specifically the Tutte polynomial is used to analyze such kind of images. Functional Magnetic Resonance Imaging provide us connectivity networks in the brain which are represented by graphs and the Tutte polynomial will be applied. The problem of computing the Tutte polynomial for a given graph is #P-hard even for planar graphs. For a practical application the maple packages "GraphTheory" and "SpecialGraphs" will be used. We will consider certain diagram which is depicting functional connectivity, specifically between frontal and posterior areas, in autism during an inferential text comprehension task. The Tutte polynomial for the resulting neural networks will be computed and some numerical invariants for such network will be obtained. Our results show that the Tutte polynomial is a powerful tool to analyze and characterize the networks obtained from functional magnetic resonance imaging.

  16. Functionalized magnetic nanoparticle analyte sensor

    DOEpatents

    Yantasee, Wassana; Warner, Maryin G; Warner, Cynthia L; Addleman, Raymond S; Fryxell, Glen E; Timchalk, Charles; Toloczko, Mychailo B

    2014-03-25

    A method and system for simply and efficiently determining quantities of a preselected material in a particular solution by the placement of at least one superparamagnetic nanoparticle having a specified functionalized organic material connected thereto into a particular sample solution, wherein preselected analytes attach to the functionalized organic groups, these superparamagnetic nanoparticles are then collected at a collection site and analyzed for the presence of a particular analyte.

  17. Functional magnetic resonance imaging at 0.2 Tesla.

    PubMed

    Stroman, P W; Malisza, K L; Onu, M

    2003-10-01

    Functional magnetic resonance imaging of healthy human volunteers was carried out at 0.2 T, using proton-density weighted (TE = 24 ms) spin-echo imaging, in order to eliminate any contribution from the blood oxygenation-level dependent (BOLD) effect. The purpose of the study was to verify the existence of a proton-density change contribution to spin-echo functional magnetic resonance imaging (fMRI) data. Results demonstrated signal intensity changes in motor and sensory areas of the brain during performance of a motor task and cold sensory stimulation of the hand, with signal changes ranging from 1.7 to 2.3%. These values are consistent with 1.9% signal changes observed previously under similar conditions at 3 T. These findings confirm the proton-density change contribution to spin-echo fMRI data and support the theory of signal enhancement by extravascular water protons (SEEP) as a non-BOLD fMRI contrast mechanism. This study also demonstrates that fMRI based on the SEEP contrast mechanism can be carried out at low fields where the BOLD effect is expected to be negligible.

  18. FUNCTIONAL AND ANATOMICAL DIFFERENCES BETWEEN CONTINENT AND INCONTINENT MEN POST RADICAL PROSTATECTOMY ON URODYNAMICS AND 3T MRI: A PILOT STUDY

    PubMed Central

    Cameron, Anne P.; Suskind, Anne M.; Neer, Charlene; Hussain, Hero; Montgomery, Jeffrey; Latini, Jerilyn M.; DeLancey, John O

    2014-01-01

    Aims There are competing hypotheses about the etiology of post prostatectomy incontinence (PPI).The purpose of this study was to determine the anatomical and functional differences between men with and without PPI. Methods Case control study of continent and incontinent men after radical prostatectomy who underwent functional and anatomic studies with urodynamics and 3.0 Tesla MRI. All men were at least 12 months post prostatectomy and none had a history of pelvic radiation or any prior surgery for incontinence. Results Baseline demographics, surgical approach and pathology were similar between incontinent (cases) (n=14) and continent (controls) (n=12) men. Among the cases, the average 24 hour pad weight was 400.0 ±176.9 grams with a mean of 2.4 ±0.7 pads per day. Urethral pressure profiles at rest did not significantly differ between groups; however with a Kegel maneuver the rise in urethral pressure was 2.6 fold higher in controls. On MRI, the urethral length was 31–35% shorter and the bladder neck was 28.9 degrees more funneled in cases. There were no differences in levator ani muscle size between groups. There was distortion of the sphincter area in 85.7% of cases and in 16.7% of controls (p=0.001). Conclusions Men with PPI were not able to increase urethral pressure with a Kegel maneuver despite similar resting urethral pressure profiles. Additionally, incontinent men had shorter urethras and were more likely to have distortion of the sphincter area. All suggesting that the sphincter in men with PPI is both diminutive and poorly functional. PMID:24752967

  19. Extracellular calcium-sensing-receptor (CaR)-mediated opening of an outward K(+) channel in murine MC3T3-E1 osteoblastic cells: evidence for expression of a functional CaR

    NASA Technical Reports Server (NTRS)

    Ye, C. P.; Yamaguchi, T.; Chattopadhyay, N.; Sanders, J. L.; Vassilev, P. M.; Brown, E. M.; O'Malley, B. W. (Principal Investigator)

    2000-01-01

    The existence in osteoblasts of the G-protein-coupled extracellular calcium (Ca(o)(2+))-sensing receptor (CaR) that was originally cloned from parathyroid and kidney remains controversial. In our recent studies, we utilized multiple detection methods to demonstrate the expression of CaR transcripts and protein in several osteoblastic cell lines, including murine MC3T3-E1 cells. Although we and others have shown that high Ca(o)(2+) and other polycationic CaR agonists modulate the function of MC3T3-E1 cells, none of these actions has been unequivocally shown to be mediated by the CaR. Previous investigations using neurons and lens epithelial cells have shown that activation of the CaR stimulates Ca(2+)-activated K(+) channels. Because osteoblastic cells express a similar type of channel, we have examined the effects of specific "calcimimetic" CaR activators on the activity of a Ca(2+)-activated K(+) channel in MC3T3-E1 cells as a way of showing that the CaR is not only expressed in those cells but is functionally active. Patch-clamp analysis in the cell-attached mode showed that raising Ca(o)(2+) from 0.75 to 2.75 mmol/L elicited about a fourfold increase in the open state probability (P(o)) of an outward K(+) channel with a conductance of approximately 92 pS. The selective calcimimetic CaR activator, NPS R-467 (0.5 micromol/L), evoked a similar activation of the channel, while its less active stereoisomer, NPSS-467 (0.5 micromol/L), did not. Thus, the CaR is not only expressed in MC3T3-E1 cells, but is also functionally coupled to the activity of a Ca(2+)-activated K(+) channel. This receptor, therefore, could transduce local or systemic changes in Ca(o)(2+) into changes in the activity of this ion channel and related physiological processes in these and perhaps other osteoblastic cells.

  20. Dissipation function in a magnetic field (Review)

    NASA Astrophysics Data System (ADS)

    Gurevich, V. L.

    2015-07-01

    The dissipation function is introduced to describe the behavior of the system of harmonic oscillations interacting with the environment (thermostat). This is a quadratic function of generalized velocities, which determines the rate of dissipation of the mechanical energy in the system. It was assumed earlier (Landau, Lifshitz) that the dissipation function can be introduced only in the absence of magnetic field. In the present review based on the author's studies, it has been shown how the dissipation function can be introduced in the presence of a magnetic field B. In a magnetic field, both dissipative and nondissipative responses arise as a response to perturbation and are expressed in terms of kinetic coefficients. The matrix of nondissipative coefficients can be obtained to determine an additional term formally including it into the equations of motion, which still satisfy the energy conservation law. Then, the dissipative part of the matrix can be considered in exactly the same way as without magnetic field, i.e., it defines the dissipation loss. As examples, the propagation and absorption of ultrasound in a metal or a semiconductor in a magnetic field have been considered using two methods: (i) the method based on the phenomenological theory using the equations of the theory of elasticity and (ii) the method based on the microscopic approach by analyzing and solving the kinetic equation. Both examples are used to illustrate the approach with the dissipation function.

  1. Dynamic 1.5-T vs 3-T true fast imaging with steady-state precession (trueFISP)-MRI sequences for assessment of velopharyngeal function

    PubMed Central

    Sinko, K; Czerny, C; Jagsch, R; Baumann, A

    2015-01-01

    Objectives: To compare the image quality of MRI scans produced with 1.5- and 3.0-T devices during functional test condition. Methods: 65 MRI scans obtained with 1.5- (n = 43) or 3.0-T (n = 22) true fast imaging with steady-state precession (trueFISP) sequences from patients with a history of a cleft palate were evaluated. Two experts assessed the MRI scans, independently of each other, and blinded to the MRI technique used. Subjective ratings were entered on a five-point Likert scale. The median planes of three anatomical structures (velum, tongue and pharyngeal wall) were assessed in three functional states (at rest, during phonation of sustained “e” and during articulation of “kkk”). In addition, MRI scans taken during velopharyngeal closure were evaluated. Results: Under blinded conditions, both observers (radiologist and orthodontist) independently rated the quality of 1.5-T scans higher than that of 3.0 T. Statistical analysis of pooled data showed that the differences were highly significant (p < 0.009) in 4 out of 10 test conditions. The greatest differences in favour of 1.5 T were observed for MRI scans of the velum. Conclusions: 1.5 T used with trueFISP may be preferable over 3.0-T trueFISP for the evaluation of the velopharyngeal structures in the clinical routine. PMID:26090932

  2. Magnetic spectroscopy and microscopy of functional materials

    SciTech Connect

    Jenkins, Catherine Ann

    2011-05-01

    Heusler intermetallics Mn2Y Ga and X2MnGa (X; Y =Fe, Co, Ni) undergo tetragonal magnetostructural transitions that can result in half metallicity, magnetic shape memory, or the magnetocaloric effect. Understanding the magnetism and magnetic behavior in functional materials is often the most direct route to being able to optimize current materials for todays applications and to design novel ones for tomorrow. Synchrotron soft x-ray magnetic spectromicroscopy techniques are well suited to explore the the competing effects from the magnetization and the lattice parameters in these materials as they provide detailed element-, valence-, and site-specifc information on the coupling of crystallographic ordering and electronic structure as well as external parameters like temperature and pressure on the bonding and exchange. Fundamental work preparing the model systems of spintronic, multiferroic, and energy-related compositions is presented for context. The methodology of synchrotron spectroscopy is presented and applied to not only magnetic characterization but also of developing a systematic screening method for future examples of materials exhibiting any of the above effects. The chapter progression is as follows: an introduction to the concepts and materials under consideration (Chapter 1); an overview of sample preparation techniques and results, and the kinds of characterization methods employed (Chapter 2); spectro- and microscopic explorations of X2MnGa/Ge (Chapter 3); spectroscopic investigations of the composition series Mn2Y Ga to the logical Mn3Ga endpoint (Chapter 4); and a summary and overview of upcoming work (Chapter 5). Appendices include the results of a Think Tank for the Graduate School of Excellence MAINZ (Appendix A) and details of an imaging project now in progress on magnetic reversal and domain wall observation in the classical Heusler material Co2FeSi (Appendix B).

  3. Functional magnetic resonance imaging using RASER

    PubMed Central

    Goerke, Ute; Garwood, Michael; Ugurbil, Kamil

    2010-01-01

    Although functional imaging of neuronal activity by magnetic resonance imaging (fMRI) has become the primary methodology employed in studying the brain, significant portions of the brain are inaccessible by this methodology due to its sensitivity to macroscopic magnetic field inhomogeneities induced near air filled cavities in the head. In this paper, we demonstrate that this sensitivity is eliminated by a novel pulse sequence, RASER (rapid acquisition by sequential excitation and refocusing) (Chamberlain et al., 2007), that can generate functional maps. This is accomplished because RASER acquired signals are purely and perfectly T2 weighted, without any T2*-effects that are inherent in the other image acquisition schemes employed to date. T2-weighted fMRI sequences are also more specific to the site of neuronal activity at ultrahigh magnetic fields than T2*-variations since they are dominated by signal components originating from the tissue in the capillary bed. The RASER based fMRI response is quantified; it is shown to have inherently less noisy time series and to provide fMRI in brain regions, such as the orbitofrontal cortex, which are challenging to image with conventional techniques. PMID:20699123

  4. Simulating functional magnetic materials on supercomputers.

    PubMed

    Gruner, Markus Ernst; Entel, Peter

    2009-07-22

    The recent passing of the petaflop per second landmark by the Roadrunner project at the Los Alamos National Laboratory marks a preliminary peak of an impressive world-wide development in the high-performance scientific computing sector. Also, purely academic state-of-the-art supercomputers such as the IBM Blue Gene/P at Forschungszentrum Jülich allow us nowadays to investigate large systems of the order of 10(3) spin polarized transition metal atoms by means of density functional theory. Three applications will be presented where large-scale ab initio calculations contribute to the understanding of key properties emerging from a close interrelation between structure and magnetism. The first two examples discuss the size dependent evolution of equilibrium structural motifs in elementary iron and binary Fe-Pt and Co-Pt transition metal nanoparticles, which are currently discussed as promising candidates for ultra-high-density magnetic data storage media. However, the preference for multiply twinned morphologies at smaller cluster sizes counteracts the formation of a single-crystalline L1(0) phase, which alone provides the required hard magnetic properties. The third application is concerned with the magnetic shape memory effect in the Ni-Mn-Ga Heusler alloy, which is a technologically relevant candidate for magnetomechanical actuators and sensors. In this material strains of up to 10% can be induced by external magnetic fields due to the field induced shifting of martensitic twin boundaries, requiring an extremely high mobility of the martensitic twin boundaries, but also the selection of the appropriate martensitic structure from the rich phase diagram.

  5. Covariant density functional theory for magnetic rotation

    NASA Astrophysics Data System (ADS)

    Peng, J.; Meng, J.; Ring, P.; Zhang, S. Q.

    2008-08-01

    The tilted axis cranking formalism is implemented in relativistic mean field (RMF) theory. It is used for a microscopic description of magnetic rotation in the framework of covariant density functional theory. We assume that the rotational axis is in the xz plane and consider systems with the two symmetries P (space reflection) and PyT (a combination of a reflection in the y direction and time reversal). A computer code based on these symmetries is developed, and first applications are discussed for the nucleus Gd142: the rotational band based on the configuration πh11/22⊗νh11/2-2 is investigated in a fully microscopic and self-consistent way. The results are compared with available data, such as spectra and electromagnetic transition ratios B(M1)/B(E2). The relation between rotational velocity and angular momentum are discussed in detail together with the shears mechanism characteristic of magnetic rotation.

  6. Functional magnetic resonance imaging studies of language.

    PubMed

    Small, Steven L; Burton, Martha W

    2002-11-01

    Functional neuroimaging of language builds on almost 150 years of study in neurology, psychology, linguistics, anatomy, and physiology. In recent years, there has been an explosion of research using functional imaging technology, especially positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), to understand the relationship between brain mechanisms and language processing. These methods combine high-resolution anatomic images with measures of language-specific brain activity to reveal neural correlates of language processing. This article reviews some of what has been learned about the neuroanatomy of language from these imaging techniques. We first discuss the normal case, organizing the presentation according to the levels of language, encompassing words (lexicon), sound structure (phonemes), and sentences (syntax and semantics). Next, we delve into some unusual language processing circumstances, including second languages and sign languages. Finally, we discuss abnormal language processing, including developmental and acquired dyslexia and aphasia.

  7. Functionalized magnetic nanoparticles: A novel heterogeneous catalyst support

    EPA Science Inventory

    Functionalized magnetic nanoparticles have emerged as viable alternatives to conventional materials, as robust, high-surface-area heterogeneous catalyst supports. Post-synthetic surface modification protocol for magnetic nanoparticles has been developed that imparts desirable che...

  8. Functionalization of magnetic nanowires by charged biopolymers.

    PubMed

    Magnin, D; Callegari, V; Mátéfi-Tempfli, S; Mátéfi-Tempfli, M; Glinel, K; Jonas, A M; Demoustier-Champagne, S

    2008-09-01

    We report on a facile method for the preparation of biocompatible and bioactive magnetic nanowires. The method consists of the direct deposition of polysaccharides by layer-by-layer (LbL) assembly onto a brush of metallic nanowires obtained by electrodeposition of the metal within the nanopores of an alumina template supported on a silicon wafer. Carboxymethylpullulan (CMP) and chitosan (CHI) multilayers were grown on brushes of Ni nanowires; subsequent grafting of an enzyme was performed by conjugating free amine side groups of chitosan with carboxylic groups of the enzyme. The nanowires are finally released by a gentle ultrasonic treatment. Transmission electron microscopy, electron energy-dispersive loss spectroscopy, and x-ray photoelectron spectroscopy indicate the formation of an homogeneous coating onto the nickel nanowires when one, two, or three CMP/CHI bilayers are deposited. This easy and efficient route to the biochemical functionalization of magnetic nanowires could find widespread use for the preparation of a broad range of nanowires with tailored surface properties. PMID:18715031

  9. Facile Surface Functionalization of Hydrophobic Magnetic Nanoparticles

    PubMed Central

    2015-01-01

    Nonpolar phase synthesized hydrophobic nanocrystals show attractive properties and have demonstrated prominent potential in biomedical applications. However, the preparation of biocompatible nanocrystals is made difficult by the presence of hydrophobic surfactant stabilizer on their surfaces. To address this limitation, we have developed a facile, high efficiency, single-phase and low-cost method to convert hydrophobic magnetic nanoparticles (MNPs) to an aqueous phase using tetrahydrofuran, NaOH and 3,4-dihydroxyhydrocinnamic acid without any complicated organic synthesis. The as-transferred hydrophilic MNPs are water-soluble over a wide pH range (pH = 3–12), and the solubility is pH-controllable. Furthermore, the as-transferred MNPs with carboxylate can be readily adapted with further surface functionalization, varying from small molecule dyes to oligonucleotides and enzymes. Finally, the strategy developed here can easily be extended to other types of hydrophobic nanoparticles to facilitate biomedical applications of nanomaterials. PMID:25140614

  10. Selecting for Function: Solution Synthesis of Magnetic Nanopropellers

    PubMed Central

    2013-01-01

    We show that we can select magnetically steerable nanopropellers from a set of carbon coated aggregates of magnetic nanoparticles using weak homogeneous rotating magnetic fields. The carbon coating can be functionalized, enabling a wide range of applications. Despite their arbitrary shape, all nanostructures propel parallel to the vector of rotation of the magnetic field. We use a simple theoretical model to find experimental conditions to select nanopropellers which are predominantly smaller than previously published ones. PMID:24127909

  11. Synthesis and characterization of functionalized magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Biswal, Dipti; Peeples, Brianna N.; Spence, Destiny D.; Peeples, Caryn; Bell, Crystal N.; Pradhan, A. K.

    2012-04-01

    Magnetic nanoparticles have been used in a wide array of industrial and biomedical applications due to their unique properties at the nanoscale level. They are extensively used in magnetic resonance imaging (MRI), magnetic hyperthermia treatment, drug delivery, and in assays for biological separations. Furthermore, superparamagnetic nanoparticles are of large interest for in vivo applications. However, these unmodified nanoparticles aggregate and consequently lose their superparamagnetic behaviors, due to high surface to volume ratio and strong dipole to dipole interaction. For these reasons, surface coating is necessary for the enhancement and effectiveness of magnetic nanoparticles to be used in various applications. In addition to providing increased stability to the nanoparticles in different solvents or media, stabilizers such as surfactants, organic/inorganic molecules, polymer and co-polymers are employed as surface coatings, which yield magnetically responsive systems. In this work we present the synthesis and magnetic characterization of Fe3O4 nanoparticles coated with 3-aminopropyltriethoxy silane (APS) and citric acid. The particles magnetic hysteresis was measured by a superconducting quantum interference device (SQUID) magnetometer with an in-plane magnetic field. The uncoated and coated magnetic nanoparticles were characterized by using fourier transform infrared (FTIR), UV-vis, X-ray diffraction, transmission electron microscopy, and thermo-gravimetric analysis.

  12. Functional study of the upregulation of miRNA-27a and miRNA-27b in 3T3-L1 cells in response to berberine.

    PubMed

    Wu, Yue-Yue; Huang, Xin-Mei; Liu, Jun; Cha, Ying; Chen, Zao-Ping; Wang, Fang; Xu, Jiong; Sheng, Li; Ding, He-Yuang

    2016-09-01

    Berberine is the major active component of Rhizoma Coptidis derived from a traditional Chinese herbal medicine and is known to regulate micro (mi)RNA levels, although the mechanism for this action remains unknown. The present study confirmed that treatment of 3T3‑L1 cells with berberine inhibited cell viability and differentiation in a dose‑ and time‑dependent manner, and significantly increased the mRNA expression levels of miRNA‑27a and miRNA‑27b. In addition, in 3T3‑L1 cells treated with berberine, overexpression of miRNA‑27a and miRNA‑27b improved the berberine-mediated inhibition of cell differentiation and reduction of triglyceride contents. By contrast, miRNA‑27a and miRNA‑27b inhibitors attenuated the berberine‑mediated inhibition of cell differentiation and reduction of triglyceride contents. Additionally, peroxisome proliferator‑activated receptors (PPAR)‑γ was confirmed to be a target of miRNA‑27a in the 3T3‑L1 cells. A dual‑luciferase reporter assay indicated that the expression of PPAR‑γ was negatively regulated by miRNA-27a. These findings may provide novel mechanistic insight into the antiobesity effects of certain compounds in traditional Chinese herbal medicine. PMID:27484069

  13. Correlation analysis between S3T and SFT/MTK vector magnetograms

    NASA Astrophysics Data System (ADS)

    Liang, H. F.; Sin, S. A.; Ma, L.

    2008-07-01

    Three components of the vector magnetic field, flux density B, inclination γ and azimuth χ of the active region NOAA10507 are derived from the two-dimensional Stokes spectral data obtained by the S3T at the Yunnan Observatory. The distributions of the longitudinal magnetic field and the transverse magnetic field are contoured on the basis of the three components. The distributions indicate that the active region is a very complicated sunspot group which is mainly composed of five sunspots, including one of negative polarity and four positive ones. Comparing the vector magnetograms obtained by S3T and the SFT/MTK, it is found that there is basic agreement on the longitudinal fields of S3T and SFT/MTK magnetograms with a correlation coefficient ρ=0.842, and the two distributions of transverse magnetic field obtained by S3T and SFT/MTK have correlation coefficients, ρ=0.423 and ρ=0.72.

  14. Plasma system of the GOL-3T facility

    SciTech Connect

    Arzhannikov, A. V.; Burdakov, A. V.; Burmasov, V. S.; Ivanov, I. A.; Kuznetsov, S. A.; Kuklin, K. N.; Mekler, K. I.; Polosatkin, S. V.; Postupaev, V. V. Rovenskikh, A. F.; Sinitsky, S. L.; Sklyarov, V. F.

    2015-11-15

    The plasma system and diagnostics of the new facility GOL-3T are described. This facility is the final result of the first stage in the deep upgrade of the GOL-3 multiple-mirror system, which has operated at the Budker Institute of Nuclear Physics since 1988. The upgrade project supposes creation of two new independent facilities at the site of GOL-3. The GOL-3T facility is intended to study the physics of beam—plasma interaction and generation of subterahertz electromagnetic radiation during the collective relaxation of a high-power relativistic electron beam with a duration of 5–10 μs. Studies on the physics of multiple-mirror plasma confinement in axisymmetric magnetic systems will be continued in a new range of experiment parameters at the second facility, named GOL-NB.

  15. Design for a high field combined function superferric magnet

    NASA Astrophysics Data System (ADS)

    Gupta, R. C.; Morgan, G. H.

    A combined function superferric magnet option was investigated for the Relativistic Heavy Ion Collider (RHIC). The option requires the maximum value of the field in the magnet to be much higher than that achieved in any existing combined function accelerator magnet. A model is presented in which a good field quality can be maintained up to 2T. It is done by carefully designing the yoke structure and positioning the coils in such a way that the iron poles tend to saturate evenly across the gap. A cold iron model might be necessary for this magnet.

  16. Increase in stability of cellulase immobilized on functionalized magnetic nanospheres

    NASA Astrophysics Data System (ADS)

    Zhang, Wenjuan; Qiu, Jianhui; Feng, Huixia; Zang, Limin; Sakai, Eiichi

    2015-02-01

    Functionalized magnetic nanospheres were prepared by co-condensation of tetraethylorthosilicate with three different amino-silanes: 3-(2-aminoethylamino propyl)-triethoxysilane (AEAPTES), 3-(2-aminoethylamino propyl)-trimethoxysilane (AEAPTMES) and 3-aminopropyltriethoxysilane (APTES). Then three functionalized magnetic nanospheres were used as supports for immobilization of cellulase. The three functionalized magnetic nanospheres with core-shell morphologies exhibited higher capacity for cellulase immobilization than unfunctionalized magnetic nanospheres. The increasing of surface charge of functionalized magnetic nanospheres leads to an enhancement of the capacity of cellulase immobilization. Particularly, AEAPTMES with methoxy groups was favored to be hydrolyzed and grafted on unfunctionalized magnetic nanospheres than the others. AEAPTMES functionalized magnetic nanospheres with the highest zeta potential (29 mV) exhibited 87% activity recovery and the maximum amount of immobilized cellulase was 112 mg/g support at concentration of initial cellulase of 8 mg/mL. Immobilized cellulase on AEAPTMES functionalized magnetic nanospheres had higher temperature stability and broader pH stability than other immobilized cellulases and free cellulase. In particular, it can be used in about 40 °C, demonstrating the potential of biofuel production using this immobilized cellulase.

  17. Magnetic Resonance, Functional (fMRI) -- Brain

    MedlinePlus

    ... powerful magnetic field, radio frequency pulses and a computer to produce detailed pictures of organs, soft tissues, ... The images can then be examined on a computer monitor, transmitted electronically, printed or copied to a ...

  18. Tumor Volume and Metabolism of Prostate Cancer Determined by Proton Magnetic Resonance Spectroscopic Imaging at 3T Without Endorectal Coil Reveal Potential Clinical Implications in the Context of Radiation Oncology;Prostate cancer; Magnetic resonance spectroscopic imaging; Radiation oncology; Tumor volume; Biomarkers

    SciTech Connect

    Crehange, Gilles; Parfait, Sebastien; Liegard, Melanie; Maingon, Philippe; Ben Salem, Douraied; Cochet, Alexandre; Funes de la Vega, Mathilde; Cormier, Luc; Bonnetain, Franck; Mirjolet, Celine; Brunotte, Francois; Walker, Paul M.

    2011-07-15

    Purpose: To determine whether a relationship exists between the tumor volume (TV) or relative choline content determined using magnetic resonance spectroscopy imaging (MRSI) at 3T and the clinical prognostic parameters for patients with localized prostate cancer (PCa). Methods and Materials: A total of 72 men (mean age, 67.8 {+-} 6.2 years) were stratified as having low-risk (n = 26), intermediate-risk (n = 24), or high-risk (n = 22) PCa. MRSI was performed at 3T using a phased-array coil. Spectra are expressed as the total choline/citrate, total choline plus creatine/citrate, and total choline plus polyamines plus creatine/citrate ratios. The mean ratio of the most pathologic voxels and the MRSI-based TV were also determined. Results: The mean values of the total choline/citrate, total choline plus creatine/citrate, and total choline plus polyamine plus creatine/citrate ratios were greater for Stage T2b or greater tumors vs. Stage T2a or less tumors: 7.53 {+-} 13.60 vs. 2.31 {+-} 5.65 (p = .018), 8.98 {+-} 14.58 vs. 2.56 {+-} 5.70 (p = .016), and 10.32 {+-} 15.47 vs. 3.55 {+-} 6.16 (p = .014), respectively. The mean MRSI-based TV for Stage T2b or greater and Stage T2a or less tumors was significantly different (2.23 {+-} 2.62 cm{sup 3} vs. 1.26 {+-} 2.06 cm{sup 3}, respectively; p = .030). This TV correlated with increased prostate-specific antigen levels (odds ratio, 1.293; p = .012). Patients with high-risk PCa had a larger TV than did the patients with intermediate-risk PCa. A similar result was found for the intermediate-risk group compared with the low-risk group (odds ratio, 1.225; p = .041). Conclusion: Biomarkers expressing the relative choline content and TV were significant parameters for the localization of PCa and could be helpful for determining the prognosis more accurately.

  19. Hybride magnetic nanostructure based on amino acids functionalized polypyrrole

    NASA Astrophysics Data System (ADS)

    Nan, Alexandrina; Bunge, Alexander; Turcu, Rodica

    2015-12-01

    Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements.

  20. Hybride magnetic nanostructure based on amino acids functionalized polypyrrole

    SciTech Connect

    Nan, Alexandrina Bunge, Alexander; Turcu, Rodica

    2015-12-23

    Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements.

  1. Amine-functionalized magnetic mesoporous silica nanoparticles for DNA separation

    NASA Astrophysics Data System (ADS)

    Sheng, Wei; Wei, Wei; Li, Junjian; Qi, Xiaoliang; Zuo, Gancheng; Chen, Qi; Pan, Xihao; Dong, Wei

    2016-11-01

    We report a modified approach for the functionalized magnetic mesoporous silica nanoparticles (MMSN) using polymer microspheres incorporated with magnetic nanoparticles in the presence of cetyltrimethylammonium bromide (CTAB) and the core-shell magnetic silica nanoparticles (MSN). These particles were functionalized with amino groups via the addition of aminosilane directly to the particle sol. We then evaluate their DNA separation abilities and find the capacity of DNA binding significantly increased (210.22 μg/mg) compared with normal magnetic silica spheres (138.44 μg/mg) by using an ultraviolet and visible spectrophotometer (UV). The morphologies, magnetic properties, particle size, pore size, core-shell structure and Zeta potential are characterized by Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), Transmission electron microscopy (TEM), Powder X-ray diffraction (XRD), and dynamic light scattering (DLS). This work demonstrates that our MMSN own an excellent potential application in bioseparation and drug delivery.

  2. Functionalization of whole‐cell bacterial reporters with magnetic nanoparticles

    PubMed Central

    Zhang, Dayi; Fakhrullin, Rawil F.; Özmen, Mustafa; Wang, Hui; Wang, Jian; Paunov, Vesselin N.; Li, Guanghe; Huang, Wei E.

    2011-01-01

    Summary We developed a biocompatible and highly efficient approach for functionalization of bacterial cell wall with magnetic nanoparticles (MNPs). Three Acinetobacter baylyi ADP1 chromosomally based bioreporters, which were genetically engineered to express bioluminescence in response to salicylate, toluene/xylene and alkanes, were functionalized with 18 ± 3 nm iron oxide MNPs to acquire magnetic function. The efficiency of MNPs functionalization of Acinetobacter bioreporters was 99.96 ± 0.01%. The MNPs‐functionalized bioreporters (MFBs) can be remotely controlled and collected by an external magnetic field. The MFBs were all viable and functional as good as the native cells in terms of sensitivity, specificity and quantitative response. More importantly, we demonstrated that salicylate sensing MFBs can be applied to sediments and garden soils, and semi‐quantitatively detect salicylate in those samples by discriminably recovering MFBs with a permanent magnet. The magnetically functionalized cells are especially useful to complex environments in which the indigenous cells, particles and impurities may interfere with direct measurement of bioreporter cells and conventional filtration is not applicable to distinguish and harvest bioreporters. The approach described here provides a powerful tool to remotely control and selectively manipulate MNPs‐functionalized cells in water and soils. It would have a potential in the application of environmental microbiology, such as bioremediation enhancement and environment monitoring and assessment. PMID:21255376

  3. Forensic age estimation via 3-T magnetic resonance imaging of ossification of the proximal tibial and distal femoral epiphyses: Use of a T2-weighted fast spin-echo technique.

    PubMed

    Ekizoglu, Oguzhan; Hocaoglu, Elif; Inci, Ercan; Can, Ismail Ozgur; Aksoy, Sema; Kazimoglu, Cemal

    2016-03-01

    Radiation exposure during forensic age estimation is associated with ethical implications. It is important to prevent repetitive radiation exposure when conducting advanced ultrasonography (USG) and magnetic resonance imaging (MRI). The purpose of this study was to investigate the utility of 3.0-T MRI in determining the degree of ossification of the distal femoral and proximal tibial epiphyses in a group of Turkish population. We retrospectively evaluated coronal T2-weighted and turbo spin-echo sequences taken upon MRI of 503 patients (305 males, 198 females; age 10-30 years) using a five-stage method. Intra- and interobserver variations were very low. (Intraobserver reliability was κ=0.919 for the distal femoral epiphysis and κ=0.961 for the proximal tibial epiphysis, and interobserver reliability was κ=0.836 for the distal femoral epiphysis and κ=0.885 for the proximal tibial epiphysis.) Spearman's rank correlation analysis indicated a significant positive relationship between age and the extent of ossification of the distal femoral and proximal tibial epiphyses (p<0.001). Comparison of male and female data revealed significant between-gender differences in the ages at first attainment of stages 2, 3, and 4 ossifications of the distal femoral epiphysis and stage 1 and 4 ossifications of the proximal tibial epiphysis (p<0.05). The earliest ages at which ossification of stages 3, 4, and 5 was evident in the distal femoral epiphysis were 14, 17, and 22 years in males and 13, 16, and 21 years in females, respectively. Proximal tibial epiphysis of stages 3, 4, and 5 ossification was first noted at ages 14, 17, and 18 years in males and 13, 15, and 16 years in females, respectively. MRI of the distal femoral and proximal tibial epiphyses is an alternative, noninvasive, and reliable technique to estimate age.

  4. Measurement of creatine kinase reaction rate in human brain using magnetization transfer image-selected in vivo spectroscopy (MT-ISIS) and a volume ³¹P/¹H radiofrequency coil in a clinical 3-T MRI system.

    PubMed

    Jeong, Eun-Kee; Sung, Young-Hoon; Kim, Seong-Eun; Zuo, Chun; Shi, Xianfeng; Mellon, Eric A; Renshaw, Perry F

    2011-08-01

    High-energy phosphate metabolism, which allows the synthesis and regeneration of adenosine triphosphate (ATP), is a vital process for neuronal survival and activity. In particular, creatine kinase (CK) serves as an energy reservoir for the rapid buffering of ATP levels. Altered CK enzyme activity, reflecting compromised high-energy phosphate metabolism or mitochondrial dysfunction in the brain, can be assessed using magnetization transfer (MT) MRS. MT (31)P MRS has been used to measure the forward CK reaction rate in animal and human brain, employing a surface radiofrequency coil. However, long acquisition times and excessive radiofrequency irradiation prevent these methods from being used routinely for clinical evaluations. In this article, a new MT (31)P MRS method is presented, which can be practically used to measure the CK forward reaction rate constant in a clinical MRI system employing a volume head (31)P coil for spatial localization, without contamination from the scalp muscle, and an acquisition time of 30 min. Other advantages associated with the method include radiofrequency homogeneity within the regions of interest of the brain using a volume coil with image-selected in vivo spectroscopy localization, and reduction of the specific absorption rate using nonadiabatic radiofrequency pulses for MT saturation. The mean value of k(f) was measured as 0.320 ± 0.075 s(-1) from 10 healthy volunteers with an age range of 18-40 years. These values are consistent with those obtained using earlier methods, and the technique may be used routinely to evaluate energetic processes in the brain on a clinical MRI system.

  5. Arbitrary function generator for APS injector synchrotron correction magnets

    SciTech Connect

    Despe, O.D.

    1990-11-07

    The APS injector synchrotron ring measures about 368 m in circumference. In order to obtain the precision of the magnetic field required for the positron acceleration from 450 Mev to 7.7 Gev with low beam loss, eighty correction magnets are distributed around its circumference. These magnets provide the vernier field changes required for beam orbit correction during the acceleration phase of the injector synchrotron cycle. Because of mechanical imperfections in the construction, as well as installation of real dipole and multi-pole magnets, the exact field correction required at each correction magnet location is not known until a beam is actually accelerated. It is therefore essential that a means is provided to generate a correction field that is a function of the beam energy from injection until extraction for each correction magnet. The fairly large number of correction magnets in the system requires that the arbitrary function generator design be as simple as possible yet provide the required performance. An important, required performance feature is that the function can be changed or modified ``on the fly``, to provide the operator with a real-time feel during the tune up process. The arbitrary function generator described in this report satisfies these requirements.

  6. Dual-source parallel radiofrequency excitation ACR phantom magnetic resonance imaging at 3 T: Assessment of the effect of image quality on high-contrast spatial resolution, percent signal ghosting, and low-contrast object detectability in comparison with conventional single-source transmission

    NASA Astrophysics Data System (ADS)

    Lee, Kyung-Bae; Park, Yong-Sung; Choe, Bo-Young

    2013-10-01

    The purpose of the present study was to assess dual-source parallel radiofrequency (RF) excitation American College of Radiology (ACR) phantom magnetic resonance (MR) imaging at 3T compared with conventional single-source RF transmission and compared with the standard ACR MRI phantom test. We used a 3T MR scanner equipped with dual-source parallel RF excitation and an 8-channel head phased array coil. We employed T1- and T2-weighted fast spin echo (FSE) pulse sequences for an assessment of the impact of image quality on high-contrast spatial resolution, percent signal ghosting and low-contrast object detectability following the ACR MRI quality control (QC) manual. With geometric accuracy and identical slice locations, dual RFs using dual-source parallel RF excitation MR showed an advantage over single RF using dual-source parallel RF excitation MR and conventional MR in terms of high-contrast spatial resolution (p < 0.010), percent signal ghosting (p < 0.010), and low-contrast object detectability (p < 0.010). The quality of the image from the dual-source parallel RF excitation MR equipment was superior to that of the image from conventional MR equipment for the ACR phantom. We need to pursue dual-source parallel RF excitation MR studies involving various clinical cases.

  7. Fuzzy logic structure analysis of trabecular bone of the calcaneus to estimate proximal femur fracture load and discriminate subjects with and without vertebral fractures using high-resolution magnetic resonance imaging at 1.5 T and 3 T.

    PubMed

    Patel, Priyesh V; Eckstein, Felix; Carballido-Gamio, Julio; Phan, Catherine; Matsuura, Maiko; Lochmüller, Eva-Maria; Majumdar, Sharmila; Link, Thomas M

    2007-10-01

    Newly developed fuzzy logic-derived structural parameters were used to characterize trabecular bone architecture in high-resolution magnetic resonance imaging (HR-MRI) of human cadaver calcaneus specimens. These parameters were compared to standard histomorphological structural measures and analyzed concerning performance in discriminating vertebral fracture status and estimating proximal femur fracture load. Sets of 60 sagittal 1.5 T and 3.0 T HR-MRI images of the calcaneus were obtained in 39 cadavers using a fast gradient recalled echo sequence. Structural parameters equivalent to bone histomorphometry and fuzzy logic-derived parameters were calculated using two chosen regions of interest. Calcaneal, spine, and hip bone mineral density (BMD) measurements were also obtained. Fracture status of the thoracic and lumbar spine was assessed on lateral radiographs. Finally, mechanical strength testing of the proximal femur was performed. Diagnostic performance in discriminating vertebral fracture status and estimating femoral fracture load was calculated using regression analyses, two-tailed t-tests of significance, and receiver operating characteristic (ROC) analyses. Significant correlations were obtained at both field strengths between all structural and fuzzy logic parameters (r up to 0.92). Correlations between histomorphological or fuzzy logic parameters and calcaneal BMD were mostly significant (r up to 0.78). ROC analyses demonstrated that standard structural parameters were able to differentiate persons with and without vertebral fractures (area under the curve [A(Z)] up to 0.73). However, none of the parameters obtained in the 1.5-T images and none of the fuzzy logic parameters discriminated persons with and without vertebral fractures. Significant correlations were found between fuzzy or structural parameters and femoral fracture load. Using multiple regression analysis, none of the structural or fuzzy parameters were found to add discriminative value to BMD

  8. Magnetic Iron Oxide Nanoparticles: Synthesis and Surface Functionalization Strategies

    NASA Astrophysics Data System (ADS)

    Wu, Wei; He, Quanguo; Jiang, Changzhong

    2008-10-01

    Surface functionalized magnetic iron oxide nanoparticles (NPs) are a kind of novel functional materials, which have been widely used in the biotechnology and catalysis. This review focuses on the recent development and various strategies in preparation, structure, and magnetic properties of naked and surface functionalized iron oxide NPs and their corresponding application briefly. In order to implement the practical application, the particles must have combined properties of high magnetic saturation, stability, biocompatibility, and interactive functions at the surface. Moreover, the surface of iron oxide NPs could be modified by organic materials or inorganic materials, such as polymers, biomolecules, silica, metals, etc. The problems and major challenges, along with the directions for the synthesis and surface functionalization of iron oxide NPs, are considered. Finally, some future trends and prospective in these research areas are also discussed.

  9. Magnetic Iron Oxide Nanoparticles: Synthesis and Surface Functionalization Strategies

    PubMed Central

    2008-01-01

    Surface functionalized magnetic iron oxide nanoparticles (NPs) are a kind of novel functional materials, which have been widely used in the biotechnology and catalysis. This review focuses on the recent development and various strategies in preparation, structure, and magnetic properties of naked and surface functionalized iron oxide NPs and their corresponding application briefly. In order to implement the practical application, the particles must have combined properties of high magnetic saturation, stability, biocompatibility, and interactive functions at the surface. Moreover, the surface of iron oxide NPs could be modified by organic materials or inorganic materials, such as polymers, biomolecules, silica, metals, etc. The problems and major challenges, along with the directions for the synthesis and surface functionalization of iron oxide NPs, are considered. Finally, some future trends and prospective in these research areas are also discussed. PMID:21749733

  10. Design, synthesis and characterization of novel binary V(V)-Schiff base materials linked with insulin-mimetic vanadium-induced differentiation of 3T3-L1 fibroblasts to adipocytes. Structure-function correlations at the molecular level.

    PubMed

    Halevas, E; Tsave, O; Yavropoulou, M P; Hatzidimitriou, A; Yovos, J G; Psycharis, V; Gabriel, C; Salifoglou, A

    2015-06-01

    Among the various roles of vanadium in the regulation of intracellular signaling, energy metabolism and insulin mimesis, its exogenous activity stands as a contemporary challenge currently under investigation and a goal to pursue as a metallodrug against Diabetes mellitus II. In this regard, the lipogenic activity of vanadium linked to the development of well-defined anti-diabetic vanadodrugs has been investigated through: a) specifically designing and synthesizing Schiff base organic ligands L, bearing a variable number of terminal alcohols, b) a series of well-defined soluble binary V(V)-L compounds synthesized and physicochemically characterized, c) a study of their cytotoxic effect and establishment of adipogenic activity in 3T3-L1 fibroblasts toward mature adipocytes, and d) biomarker examination of a closely-linked molecular target involving or influenced by the specific V(V) forms, cumulatively delineating factors involved in potential pathways linked to V(V)-induced insulin-like activity. Collectively, the results a) project the importance of specific structural features in Schiff ligands bound to V(V), thereby influencing the emergence of its (a)toxicity and for the first time its insulin-like activity in pre-adipocyte differentiation, b) contribute to the discovery of molecular targets influenced by the specific vanadoforms seeking to induce glucose uptake, and c) indicate an interplay of V(V) structural speciation and cell-differentiation biological activity, thereby gaining insight into vanadium's potential as a future metallodrug in Diabetes mellitus.

  11. High-Permittivity Thin Dielectric Padding Improves Fresh Blood Imaging of Femoral Arteries at 3T

    PubMed Central

    Lindley, Marc D; Kim, Daniel; Morrell, Glen; Heilbrun, Marta E; Storey, Pippa; Hanrahan, Christopher J; Lee, Vivian S

    2014-01-01

    Objectives Fresh blood imaging (FBI) is a useful non-contrast magnetic resonance angiography (NC-MRA) method for assessment of peripheral arterial disease (PAD), particularly in patients with poor renal function. Compared with 1.5T, 3T enables higher signal to noise ratio (SNR) and/or spatio-temporal resolution in FBI, as demonstrated successfully for the calf station. However, FBI of the thigh station at 3T has been reported to suffer from signal void in the common femoral artery of one thigh only due to the radial symmetry in transmit radio-frequency field (B1+) variation. We sought to increase the femoral arterial signal attenuated by B1+ variation in FBI at 3T using high permittivity dielectric padding. Materials and Methods We performed FBI of the thigh station in 13 human subjects at 3T to compare the following 3 settings: no padding, commercially available thick (~ 5 cm) dielectric padding, and high-permittivity thin (~2 cm) dielectric padding. B1+ mapping was also performed in the common femoral arteries to characterize the radial symmetry in B1+ variation and quantify the improvement in B1+ excitation. We characterized the impact of radial symmetry in B1+ variation on the FBI signal and FBI MRA of the right common femoral artery using quantitative (i.e., contrast-to-noise ratio (CNR)) and qualitative (i.e., conspicuity) analyses. Results The radial symmetry in B1+ variation attenuates signal in the right common femoral artery, which can be partially improved with commercial padding and improved further with high permittivity padding. Averaging the results over 13 subjects, the B1+, CNR and conspicuity scores in the right common femoral artery were significantly better with high-permittivity padding than with commercial padding and baseline (p<0.001). Conclusions Our study shows that high-permittivity dielectric padding can be used to increase the femoral arterial signal attenuated by B1+ variation in FBI at 3T. PMID:25329606

  12. A comparison of distributional considerations with statistical analysis of resting state fMRI at 3T and 7T

    NASA Astrophysics Data System (ADS)

    Yang, Xue; Holmes, Martha J.; Newton, Allen T.; Morgan, Victoria L.; Landman, Bennett A.

    2012-02-01

    Ultra-high field 7T magnetic resonance imaging (MRI) offers potentially unprecedented spatial resolution of functional activity within the human brain through increased signal and contrast to noise ratios over traditional 1.5T and 3T MRI scanners. However, the effects physiological and imaging artifacts are also greatly increased. Traditional statistical parametric mapping theories based on distributional properties representative of data acquired at lower fields may be inadequate for new 7T data. Herein, we investigate the model fitting residuals based on two 7T and one 3T protocols. We find that model residuals are substantively more non-Gaussian at 7T relative to 3T. Imaging slices that passed through regions with peak inhomogeneity problems (e.g., mid-brain acquisitions for the 7T hippocampus) exhibited visually higher degrees of distortion along with spatially correlated and extreme values of kurtosis (a measure of non- Gaussianity). The impacts of artifacts have been previously addressed for 3T data by estimating the covariance matrix of the regression errors. We further extend the robust estimation approach for autoregressive models and evaluate the qualitative impacts of this technique relative to traditional inference. Clear differences in statistical significance are shown between inferences based on classical versus robust assumptions, which suggest that inferences based on Gaussian assumptions are subject to practical (as well as theoretical) concerns regarding their power and validity. Hence, modern statistical approaches, such as the robust autoregressive model posed herein, are appropriate and suitable for inference with ultra-high field functional magnetic resonance imaging.

  13. Functionalization of polydopamine coated magnetic nanoparticles with biological entities

    NASA Astrophysics Data System (ADS)

    Mǎgeruşan, Lidia; Mrówczyński, Radosław; Turcu, Rodica

    2015-12-01

    New hybrid materials, obtained through introduction of cysteine, lysine and folic acid as biological entities into polydopamine-coated magnetite nanoparticles, are reported. The syntheses are straight forward and various methods were applied for structural and morphological characterization of the resulting nanoparticles. XPS proved a very powerful tool for surface chemical analysis and it evidences the functionalization of polydopamine coated magnetite nanoparticles. The superparamagnetic behavior and the high values of saturation magnetization recommend all products for further application where magnetism is important for targeting, separation, or heating by alternative magnetic fields.

  14. Growth stimulation of 3T3 fibroblasts by Cystatin

    SciTech Connect

    Quan Sun Beijing Medical Univ. )

    1989-01-01

    Treatment of cultures of mouse 3T3 fibroblasts with Cystatin C, a thiol-proteinase inhibitor isolated from chicken egg white, resulted in an enhanced rate of cell proliferation. This stimulation was demonstrated using two independent assay systems: (a) assessment of total cell number and (b) measurement of ({sup 3}H)thymidine incorporated into acid-precipitable DNA. In both assays, the dose-response curves of Cystatin stimulation showed a rising function that plateaued at a concentration of {approximately}120 {mu}g/ml. The addition of Cystatin to cultures of Kirsten murine sarcoma virus-transformed 3T3 cells also enhanced DNA synthesis in these target cells. Control experiments showed that the presence of Cystatin did not alter the level of binding of radioactively labeled epidermal growth factor and platelet derived growth factor to 3T3 cells. These results argue against the possibility that the observed growth stimulation by Cystatin was due to growth factor contamination of the Cystatin preparation.

  15. Lysophosphatidic acid receptor-5 negatively regulates cellular responses in mouse fibroblast 3T3 cells

    SciTech Connect

    Dong, Yan; Hirane, Miku; Araki, Mutsumi; Fukushima, Nobuyuki; Tsujiuchi, Toshifumi

    2014-04-04

    Highlights: • LPA{sub 5} inhibits the cell growth and motile activities of 3T3 cells. • LPA{sub 5} suppresses the cell motile activities stimulated by hydrogen peroxide in 3T3 cells. • Enhancement of LPA{sub 5} on the cell motile activities inhibited by LPA{sub 1} in 3T3 cells. • The expression and activation of Mmp-9 were inhibited by LPA{sub 5} in 3T3 cells. • LPA signaling via LPA{sub 5} acts as a negative regulator of cellular responses in 3T3 cells. - Abstract: Lysophosphatidic acid (LPA) signaling via G protein-coupled LPA receptors (LPA{sub 1}–LPA{sub 6}) mediates a variety of biological functions, including cell migration. Recently, we have reported that LPA{sub 1} inhibited the cell motile activities of mouse fibroblast 3T3 cells. In the present study, to evaluate a role of LPA{sub 5} in cellular responses, Lpar5 knockdown (3T3-L5) cells were generated from 3T3 cells. In cell proliferation assays, LPA markedly stimulated the cell proliferation activities of 3T3-L5 cells, compared with control cells. In cell motility assays with Cell Culture Inserts, the cell motile activities of 3T3-L5 cells were significantly higher than those of control cells. The activity levels of matrix metalloproteinases (MMPs) were measured by gelatin zymography. 3T3-L5 cells stimulated the activation of Mmp-2, correlating with the expression levels of Mmp-2 gene. Moreover, to assess the co-effects of LPA{sub 1} and LPA{sub 5} on cell motile activities, Lpar5 knockdown (3T3a1-L5) cells were also established from Lpar1 over-expressing (3T3a1) cells. 3T3a1-L5 cells increased the cell motile activities of 3T3a1 cells, while the cell motile activities of 3T3a1 cells were significantly lower than those of control cells. These results suggest that LPA{sub 5} may act as a negative regulator of cellular responses in mouse fibroblast 3T3 cells, similar to the case for LPA{sub 1}.

  16. Functional magnetic resonance imaging in neurology.

    PubMed

    Auer, Tibor; Schwarcz, Attila; Horváth, Réka A; Barsi, Péter; Janszky, József

    2008-01-30

    The present contribution discusses the clinical use of functional MRI (fMRI) and its role in the most common neurological diseases. FMRI was found a reliable and reproducible examination tool resulting in a wide distribution of fMRI methods in presurgical evaluation of epilepsy in determining the relationship of eloquent areas and the epileptic focus. Preliminary data suggest that fMRI using memory paradigms can predict the postoperative memory decline in epilepsy surgery by determining whether a reorganization of memory functions took place. Speech-activated fMRI became the most used tool in determining hemispheric dominance. Visual and sensory-motor cortex can also be routinely investigated by fMRI which helps in decision on epilepsy surgery. FMRI combined with EEG is a new diagnostic tool in epilepsy and sleep disorders. FMRI can identify the penumbra after stroke and can provide an additional information on metabolic state of the threatened brain tissue. FMRI has a predictive role in post-stroke recovery. In relapsing-remitting MS an adaptive reorganization can be demonstrated by fMRI affecting the visual, motor, and memory systems, despite preserved functional performance. Much more extensive reorganization can be demonstrated in secondary progressive MS. These findings suggest that the different stages of MS are related to different stages of the reorganization and MS becomes progressive when there is no more reserve capacity in the brain for reorganization. FMRI offers the capability of detecting early functional hemodynamic alterations in Alzheimer's disease before morphological changes. FMRI can be a valuable tool to test and monitor treatment efficacy in AD. FMRI can also provide information about the mechanisms of different therapeutic approaches in Parkinson disorder including drug treatment and deep brain stimulation.

  17. Seven topics in functional magnetic resonance imaging.

    PubMed

    Bandettini, Peter A

    2009-09-01

    Functional MRI (fMRI) is a non-invasive brain imaging methodology that started in 1991 and allows human brain activation to be imaged at high resolution within only a few minutes. Because it has extremely high sensitivity, is relatively easy to implement, and can be performed on most standard clinical MRI scanners. It continues to grow at an explosive rate throughout the world. Over the years, at any given time, fMRI has been defined by only a handful of major topics that have been the focus of researchers using and developing the methodology. In this review, I attempt to take a snapshot of the field of fMRI as it is in mid-2009 by discussing the seven topics that I feel are most on the minds of fMRI researchers. The topics are, in no particular order or grouping: (1) Clinical impact, (2) Utilization of individual functional maps, (3) fMRI signal interpretation, (4) Pattern effect mapping and decoding, (5) Endogenous oscillations, (6) MRI technology, and (7) Alternative functional contrast mechanisms. Most of these topics are highly interdependent, each advancing as the others advance. While most fMRI involves applications towards clinical or neuroscience questions, all applications are fundamentally dependent on advances in basic methodology as well as advances in our understanding of the relationship between neuronal activity and fMRI signal changes. This review neglects almost completely an in-depth discussion of applications. Rather the discussions are on the methods and interpretation.

  18. SEVEN TOPICS IN FUNCTIONAL MAGNETIC RESONANCE IMAGING

    PubMed Central

    BANDETTINI, PETER A.

    2010-01-01

    Functional MRI (fMRI) is a non-invasive brain imaging methodology that started in 1991 and allows human brain activation to be imaged at high resolution within only a few minutes. Because it has extremely high sensitivity, is relatively easy to implement, and can be performed on most standard clinical MRI scanners. It continues to grow at an explosive rate throughout the world. Over the years, at any given time, fMRI has been defined by only a handful of major topics that have been the focus of researchers using and developing the methodology. In this review, I attempt to take a snapshot of the field of fMRI as it is in mid-2009 by discussing the seven topics that I feel are most on the minds of fMRI researchers. The topics are, in no particular order or grouping: (1) Clinical impact, (2) Utilization of individual functional maps, (3) fMRI signal interpretation, (4) Pattern effect mapping and decoding, (5) Endogenous oscillations, (6) MRI technology, and (7) Alternative functional contrast mechanisms. Most of these topics are highly interdependent, each advancing as the others advance. While most fMRI involves applications towards clinical or neuroscience questions, all applications are fundamentally dependent on advances in basic methodology as well as advances in our understanding of the relationship between neuronal activity and fMRI signal changes. This review neglects almost completely an in-depth discussion of applications. Rather the discussions are on the methods and interpretation. PMID:19938211

  19. Surface functionalized biocompatible magnetic nanospheres for cancer hyperthermia.

    SciTech Connect

    Liu, X.; Novosad, V.; Rozhkova, E. A.; Chen, H.; Yefremenko, V.; Pearson, J.; Torno, M.; Bader, S. D.; Rosengart, A. J.; Univ. Chicago Pritzker School of Medicine

    2007-06-01

    We report a simplified single emulsion (oil-in-water) solvent evaporation protocol to synthesize surface functionalized biocompatible magnetic nanospheres by using highly concentrated hydrophobic magnetite (gel) and a mixture of poly(D,L lactide-co-glycolide) (PLGA) and poly(lactic acid-block-polyethylene glycol-maleimide) (PLA-PEG-maleimide) (10:1 by mass) polymers. The as-synthesized particles are approximately spherical with an average diameter of 360-370 nm with polydispersity index of 0.12-0.18, are surface-functionalized with maleimide groups, and have saturation magnetization values of 25-40 emu/g. The efficiency of the heating induced by 400-kHz oscillating magnetic fields is compared for two samples with different magnetite loadings. Results show that these nanospheres have the potential to provide an efficient cancer-targeted hyperthermia.

  20. Peptide-functionalized magnetic nanoparticles for cancer therapy applications

    NASA Astrophysics Data System (ADS)

    Hauser, Anastasia Kruse

    Lung cancer is one of the leading causes of cancer deaths in the United States. Radiation and chemotherapy are conventional treatments, but they result in serious side effects and the probability of tumor recurrence remains high. Therefore, there is an increasing need to enhance the efficacy of conventional treatments. Magnetic nanoparticles have been previously studied for a variety of applications such as magnetic resonance imaging contrast agents, anemia treatment, magnetic cell sorting and magnetically mediated hyperthermia (MMH). In this work, dextran coated iron oxide nanoparticles were developed and functionalized with peptides to target the nanoparticles to either the extracellular matrix (ECM) of tumor tissue or to localize the nanoparticles in subcellular regions after cell uptake. The magnetic nanoparticles were utilized for a variety of applications. First, heating properties of the nanoparticles were utilized to administer hyperthermia treatments combined with chemotherapy. The nanoparticles were functionalized with peptides to target fibrinogen in the ECM and extensively characterized for their physicochemical properties, and MMH combined with chemotherapy was able to enhance the toxicity of chemotherapy. The second application of the nanoparticles was magnetically mediated energy delivery. This treatment does not result in a bulk temperature rise upon actuation of the nanoparticles by an alternating magnetic field (AMF) but rather results in intracellular damage via friction from Brownian rotation or nanoscale heating effects from Neel relaxations. The nanoparticles were functionalized with a cell penetrating peptide to facilitate cell uptake and lysosomal escape. The intracellular effects of the internalized nanoparticles alone and with activation by an AMF were evaluated. Iron concentrations in vivo are highly regulated as excess iron can catalyze the formation of the hydroxyl radical through Fenton chemistry. Although often a concern of using iron

  1. Functional Connectivity Magnetic Resonance Imaging Classification of Autism

    ERIC Educational Resources Information Center

    Anderson, Jeffrey S.; Nielsen, Jared A.; Froehlich, Alyson L.; DuBray, Molly B.; Druzgal, T. Jason; Cariello, Annahir N.; Cooperrider, Jason R.; Zielinski, Brandon A.; Ravichandran, Caitlin; Fletcher, P. Thomas; Alexander, Andrew L.; Bigler, Erin D.; Lange, Nicholas; Lainhart, Janet E.

    2011-01-01

    Group differences in resting state functional magnetic resonance imaging connectivity between individuals with autism and typically developing controls have been widely replicated for a small number of discrete brain regions, yet the whole-brain distribution of connectivity abnormalities in autism is not well characterized. It is also unclear…

  2. Human brain somatic representation: a functional magnetic resonance mapping

    NASA Astrophysics Data System (ADS)

    Romero-Romo, Juan; Rojas, Rafael; Salgado, Perla; Sánchez-Cortázar, Julián; Vazquez-Vela, Arturo; Barrios, Fernando A.

    2001-10-01

    Central nervous system studies of injury and plasticity for the reorganization in the phantom limb sensation area presented. In particular functional magnetic resonance imaging (fMRI) mapping of the somatic and motor cortex of amputee patients, in the case of referred sensations. Using fMRI we can show the correlation between structure and functional field and study the reorganization due to plasticity in the brain.

  3. Electronic and magnetic properties of functionalized BN sheet

    NASA Astrophysics Data System (ADS)

    Sun, Qiang; Zhou, Jian; Wang, Qian; Jena, Puru

    2010-03-01

    First principles calculations based on density functional theory reveal some unusual properties of BN sheet functionalized with hydrogen and fluorine. These properties differ from those of similarly functionalized graphene even though both share the same honeycomb structure. (1) Unlike graphene which undergoes a metal to insulator transition when fully hydrogenated, the band gap of the BN sheet significantly narrows when fully saturated with hydrogen. Furthermore, the band gap of the BN sheet can be tuned from 4.7 eV to 0.6 eV and the system can be a direct or an indirect semiconductor or even a half-metal depending upon surface coverage. (2) Unlike graphene, BN sheet, due to its hetero-atomic composition, permits the surface to be co-decorated with H and F, thus leading to anisotropic structures with rich electronic and magnetic properties. (3) Unlike graphene, BN sheets can be made ferromagnetic, antiferromagnetic, or magnetically degenerate depending upon how the surface is functionalized. (4) Unlike graphene, the stability of magnetic coupling of functionalized BN sheet can be modulated by applying external strain. Our study highlights the potential of functionalized BN sheets for novel applications.

  4. Functional magnetic resonance imaging in medicine and physiology

    SciTech Connect

    Moonen, C.T.W.; van Zijl, P.C.M.; Frank, J.A.; Bihan, D.L.; Becker, E.D. )

    1990-10-05

    Magnetic resonance imaging (MRI) is a well-established diagnostic tool that provides detailed information about macroscopic structure and anatomy. Recent advances in MRI allow the noninvasive spatial evaluation of various biophysical and biochemical processes in living systems. Specifically, the motion of water can be measured in processes such as vascular flow, capillary flow, diffusion, and exchange. In addition, the concentrations of various metabolites can be determined for the assessment of regional regulation of metabolism. Examples are given that demonstrate the use of functional MRI for clinical and research purposes. This development adds a new dimension to the application of magnetic resonance to medicine and physiology.

  5. Advances in Langmuir probe diagnostics of the plasma potential and electron-energy distribution function in magnetized plasma

    NASA Astrophysics Data System (ADS)

    Popov, Tsv K.; Dimitrova, M.; Ivanova, P.; Kovačič, J.; Gyergyek, T.; Dejarnac, R.; Stöckel, J.; Pedrosa, M. A.; López-Bruna, D.; Hidalgo, C.

    2016-06-01

    Advanced Langmuir probe techniques for evaluating the plasma potential and electron-energy distribution function (EEDF) in magnetized plasma are reviewed. It is shown that when the magnetic field applied is very weak and the electrons reach the probe without collisions in the probe sheath the second-derivative Druyvesteyn formula can be used for EEDF evaluation. At low values of the magnetic field, an extended second-derivative Druyvesteyn formula yields reliable results, while at higher values of the magnetic field, the first-derivative probe technique is applicable for precise evaluation of the plasma potential and the EEDF. There is an interval of intermediate values of the magnetic field when both techniques—the extended second-derivative and the first-derivative one—can be used. Experimental results from probe measurements in different ranges of magnetic field are reviewed and discussed: low-pressure argon gas discharges in the presence of a magnetic field in the range from 0.01 to 0.08 T, probe measurements in circular hydrogen plasmas for high-temperature fusion (magnetic fields from 0.45 T to 1.3 T) in small ISTTOK and CASTOR tokamaks, D-shape COMPASS tokamak plasmas, as well as in the TJ-II stellarator. In the vicinity of the last closed flux surface (LCFS) in tokamaks and in the TJ-II stellarator, the EEDF obtained is found to be bi-Maxwellian, while close to the tokamak chamber wall it is Maxwellian. The mechanism of the appearance of a bi-Maxwellian EEDF in the vicinity of the LCFS is discussed. Comparison of the results from probe measurements with those obtained from calculations using the ASTRA and EIRENE codes shows that the main reason for the appearance of a bi-Maxwellian EEDF in the vicinity of the LCFS is the ionization of the neutral atoms.

  6. Assessment of cardiac function: magnetic resonance and computed tomography.

    PubMed

    Greenberg, S B

    2000-10-01

    A complete cardiac study requires both anatomic and physiologic evaluation. Cardiac function can be evaluated noninvasively by magnetic resonance imaging (MRI)or ultrafast computed tomography (CT). MRI allows for evaluation of cardiac function by cine gradient echo imaging of the ventricles and flow analysis across cardiac valves and the great vessels. Cine gradient echo imaging is useful for evaluation of cardiac wall motion, ventricular volumes and ventricular mass. Flow analysis allows for measurement of velocity and flow during the cardiac cycle that reflects cardiac function. Ultrafast CT allows for measurement of cardiac indices similar to that provided by gradient echo imaging of the ventricles.

  7. Exponentially localized Wannier functions in periodic zero flux magnetic fields

    NASA Astrophysics Data System (ADS)

    De Nittis, G.; Lein, M.

    2011-11-01

    In this work, we investigate conditions which ensure the existence of an exponentially localized Wannier basis for a given periodic hamiltonian. We extend previous results [Panati, G., Ann. Henri Poincare 8, 995-1011 (2007), 10.1007/s00023-007-0326-8] to include periodic zero flux magnetic fields which is the setting also investigated by Kuchment [J. Phys. A: Math. Theor. 42, 025203 (2009), 10.1088/1751-8113/42/2/025203]. The new notion of magnetic symmetry plays a crucial rôle; to a large class of symmetries for a non-magnetic system, one can associate "magnetic" symmetries of the related magnetic system. Observing that the existence of an exponentially localized Wannier basis is equivalent to the triviality of the so-called Bloch bundle, a rank m hermitian vector bundle over the Brillouin zone, we prove that magnetic time-reversal symmetry is sufficient to ensure the triviality of the Bloch bundle in spatial dimension d = 1, 2, 3. For d = 4, an exponentially localized Wannier basis exists provided that the trace per unit volume of a suitable function of the Fermi projection vanishes. For d > 4 and d ⩽ 2m (stable rank regime) only the exponential localization of a subset of Wannier functions is shown; this improves part of the analysis of Kuchment [J. Phys. A: Math. Theor. 42, 025203 (2009), 10.1088/1751-8113/42/2/025203]. Finally, for d > 4 and d > 2m (unstable rank regime) we show that the mere analysis of Chern classes does not suffice in order to prove triviality and thus exponential localization.

  8. Isolation of highly suppressive CD25+FoxP3+ T regulatory cells from G-CSF-mobilized donors with retention of cytotoxic anti-viral CTLs: application for multi-functional immunotherapy post stem cell transplantation.

    PubMed

    Samuel, Edward R; Beloki, Lorea; Newton, Katy; Mackinnon, Stephen; Lowdell, Mark W

    2014-01-01

    Previous studies have demonstrated the effective control of cytomegalovirus (CMV) infections post haematopoietic stem cell transplant through the adoptive transfer of donor derived CMV-specific T cells (CMV-T). Strategies for manufacturing CMV immunotherapies has involved a second leukapheresis or blood draw from the donor, which in the unrelated donor setting is not always possible. We have investigated the feasibility of using an aliquot of the original G-CSF-mobilized graft as a starting material for manufacture of CMV-T and examined the activation marker CD25 as a targeted approach for identification and isolation following CMVpp65 peptide stimulation. CD25+ cells isolated from G-CSF-mobilized apheresis revealed a significant increase in the proportion of FoxP3 expression when compared with conventional non-mobilized CD25+ cells and showed a superior suppressive capacity in a T cell proliferation assay, demonstrating the emergence of a population of Tregs not present in non-mobilized apheresis collections. The expansion of CD25+ CMV-T in short-term culture resulted in a mixed population of CD4+ and CD8+ T cells with CMV-specificity that secreted cytotoxic effector molecules and lysed CMVpp65 peptide-loaded phytohaemagglutinin-stimulated blasts. Furthermore CD25 expanded cells retained their suppressive capacity but did not maintain FoxP3 expression or secrete IL-10. In summary our data indicates that CD25 enrichment post CMV stimulation in G-CSF-mobilized PBMCs results in the simultaneous generation of both a functional population of anti-viral T cells and Tregs thus illustrating a potential single therapeutic strategy for the treatment of both GvHD and CMV reactivation following allogeneic haematopoietic stem cell transplantation. The use of G-CSF-mobilized cells as a starting material for cell therapy manufacture represents a feasible approach to alleviating the many problems incurred with successive donations and procurement of cells from unrelated donors

  9. Characterization of hyaluronate binding proteins isolated from 3T3 and murine sarcoma virus transformed 3T3 cells

    SciTech Connect

    Turley, E.A.; Moore, D.; Hayden, L.J.

    1987-06-02

    A hyaluronic acid binding fraction was purified from the supernatant media of both 3T3 and murine sarcoma virus (MSV) transformed 3T3 cultures by hyaluronate and immunoaffinity chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis resolved the hyaluronate affinity-purified fraction into three major protein bands of estimated molecular weight (M/sub r,e/) 70K, 66K, and 56K which contained hyaluronate binding activity and which were termed hyaluronate binding proteins (HABP). Hyaluronate affinity chromatography combined with immunoaffinity chromatography, using antibody directed against the larger HABP, allowed a 20-fold purification of HABP. Fractions isolated from 3T3 supernatant medium also contained additional binding molecules in the molecular weight range of 20K. This material was present in vanishingly small amounts and was not detected with a silver stain or with (/sup 35/S)methionine label. The three protein species isolated by hyaluronate affinity chromatography (M/sub r,e/ 70K, 66K, and 56K) were related to one another since they shared antigenic determinants and exhibited similar pI values. In isocratic conditions, HABP occurred as aggregates of up to 580 kilodaltons. Their glycoprotein nature was indicated by their incorporation of /sup 3/H-sugars. Enzyme-linked immunoadsorbent assay showed they were antigenically distinct from other hyaluronate binding proteins such as fibronectin, cartilage link protein, and the hyaluronate binding region of chondroitin sulfate proteoglycan. The results are discussed with regard both to the functional significance of hyaluronate-cell surface interactions in transformed as well as normal cells and to the relationship of HABP to other reported hyaluronate binding proteins.

  10. Functional magnetic resonance imaging in oncology: state of the art*

    PubMed Central

    Guimaraes, Marcos Duarte; Schuch, Alice; Hochhegger, Bruno; Gross, Jefferson Luiz; Chojniak, Rubens; Marchiori, Edson

    2014-01-01

    In the investigation of tumors with conventional magnetic resonance imaging, both quantitative characteristics, such as size, edema, necrosis, and presence of metastases, and qualitative characteristics, such as contrast enhancement degree, are taken into consideration. However, changes in cell metabolism and tissue physiology which precede morphological changes cannot be detected by the conventional technique. The development of new magnetic resonance imaging techniques has enabled the functional assessment of the structures in order to obtain information on the different physiological processes of the tumor microenvironment, such as oxygenation levels, cellularity and vascularity. The detailed morphological study in association with the new functional imaging techniques allows for an appropriate approach to cancer patients, including the phases of diagnosis, staging, response evaluation and follow-up, with a positive impact on their quality of life and survival rate. PMID:25741058

  11. Magnetic anisotropy of metal functionalized phthalocyanine 2D networks

    NASA Astrophysics Data System (ADS)

    Zhu, Guojun; Zhang, Yun; Xiao, Huaping; Cao, Juexian

    2016-06-01

    The magnetic anisotropy of metal including Cr, Mn, Fe, Co, Mo, Tc, Ru, Rh, W, Re, Os, Ir atoms functionalized phthalocyanine networks have been investigated with first-principles calculations. The magnetic moments can be expressed as 8-n μB with n the electronic number of outmost d shell in the transition metals. The huge magnetocrystalline anisotropy energy (MAE) is obtained by torque method. Especially, the MAE of Re functionalized phthalocyanine network is about 20 meV with an easy axis perpendicular to the plane of phthalocyanine network. The MAE is further manipulated by applying the external biaxial strain. It is found that the MAE is linear increasing with the external strain in the range of -2% to 2%. Our results indicate an effective approach to modulate the MAE for practical application.

  12. Functional magnetic resonance imaging in oncology: state of the art.

    PubMed

    Guimaraes, Marcos Duarte; Schuch, Alice; Hochhegger, Bruno; Gross, Jefferson Luiz; Chojniak, Rubens; Marchiori, Edson

    2014-01-01

    In the investigation of tumors with conventional magnetic resonance imaging, both quantitative characteristics, such as size, edema, necrosis, and presence of metastases, and qualitative characteristics, such as contrast enhancement degree, are taken into consideration. However, changes in cell metabolism and tissue physiology which precede morphological changes cannot be detected by the conventional technique. The development of new magnetic resonance imaging techniques has enabled the functional assessment of the structures in order to obtain information on the different physiological processes of the tumor microenvironment, such as oxygenation levels, cellularity and vascularity. The detailed morphological study in association with the new functional imaging techniques allows for an appropriate approach to cancer patients, including the phases of diagnosis, staging, response evaluation and follow-up, with a positive impact on their quality of life and survival rate.

  13. Lanthanide-Functionalized Hydrophilic Magnetic Hybrid Nanoparticles: Assembly, Magnetic Behaviour, and Photophysical Properties

    NASA Astrophysics Data System (ADS)

    Han, Shuai; Tang, Yu; Guo, Haijun; Qin, Shenjun; Wu, Jiang

    2016-05-01

    The lanthanide-functionalized multifunctional hybrid nanoparticles combining the superparamagnetic core and the luminescent europium complex were successfully designed and assembled via layer-by-layer strategy in this work. It is noted that the hybrid nanoparticles were modified by a hydrophilic polymer polyethyleneimine (PEI) through hydrogen bonding which bestowed excellent hydrophilicity and biocompatibility on this material. A bright-red luminescence was observed by fluorescence microscopy, revealing that these magnetic-luminescent nanoparticles were both colloidally and chemically stable in PBS solution. Therefore, the nanocomposite with magnetic resonance response and fluorescence probe property is considered to be of great potential in multi-modal bioimaging and diagnostic applications.

  14. Lanthanide-Functionalized Hydrophilic Magnetic Hybrid Nanoparticles: Assembly, Magnetic Behaviour, and Photophysical Properties.

    PubMed

    Han, Shuai; Tang, Yu; Guo, Haijun; Qin, Shenjun; Wu, Jiang

    2016-12-01

    The lanthanide-functionalized multifunctional hybrid nanoparticles combining the superparamagnetic core and the luminescent europium complex were successfully designed and assembled via layer-by-layer strategy in this work. It is noted that the hybrid nanoparticles were modified by a hydrophilic polymer polyethyleneimine (PEI) through hydrogen bonding which bestowed excellent hydrophilicity and biocompatibility on this material. A bright-red luminescence was observed by fluorescence microscopy, revealing that these magnetic-luminescent nanoparticles were both colloidally and chemically stable in PBS solution. Therefore, the nanocomposite with magnetic resonance response and fluorescence probe property is considered to be of great potential in multi-modal bioimaging and diagnostic applications. PMID:27245169

  15. Functional magnetic resonance imaging of the brain: a quick review.

    PubMed

    Vaghela, Viratsinh; Kesavadas, Chandrasekharan; Thomas, Bejoy

    2010-01-01

    Ability to non-invasively map the hemodynamic changes occurring focally in areas of brain involved in various motor, sensory and cognitive functions by functional magnetic resonance imaging (fMRI) has revolutionized research in neuroscience in the last two decades. This technique has already gained clinical use especially in pre-surgical evaluation of epilepsy and neurosurgical planning of resection of mass lesions adjacent to eloquent cortex. In this review we attempt to illustrate basic principles and techniques of fMRI, its applications, practical points to consider while performing and evaluating clinical fMRI and its limitations.

  16. Magnetic Alignment and Charge Transport Improvement in Functional Soft Materials

    NASA Astrophysics Data System (ADS)

    Majewski, Pawel W.

    The realization of nanostructured functional materials by self-assembly in polymers and polymer nanocomposites is adversely affected by persisting structural defects which greatly diminish the performance of the material. The use of magnetic fields to impose long-range order is investigated in three distinct systems - ion-conducting block copolymers, semiconducting nanowire-polymer composites and lyotropic surfactant mesophases. The alignment process is quantitatively studied with X-ray scattering and microscopic methods. Time and temperature resolved data collected in situ during the magnetic experiments provide an insight into the thermodynamic and kinetic aspects of the process. These data together with simultaneous electrical conductivity measurements allow relating fundamental structural properties (e.g., morphology and long-range order) to transport properties (i.e., conductivity). In particular, it is demonstrated that magnetic fields offer a viable route for improvement of electric conductivity in these systems. More than an order of magnitude increase in conductivity is recorded in magnetically-annealed materials. The resulting aligned nanostructured systems are attractive for ordered solid polymer electrolyte membranes, heterojunction photovoltaic devices and generally help to understand charge transport mechanisms in anisotropic heterogeneous systems.

  17. Functionalized magnetic-fluorescent hybrid nanoparticles for cell labelling.

    PubMed

    Lou, Lei; Yu, Ke; Zhang, Zhengli; Li, Bo; Zhu, Jianzhong; Wang, Yiting; Huang, Rong; Zhu, Ziqiang

    2011-05-01

    A facile method of synthesizing 60 nm magnetic-fluorescent core-shell bifunctional nanocomposites with the ability to label cells is presented. Hydrophobic trioctylphosphine oxide (TOPO)-capped CdSe@ZnS quantum dots (QDs) were assembled on polyethyleneimine (PEI)-coated Fe(3)O(4) nanoparticles (MNP). Polyethyleneimine was utilized for the realization of multifunction, including attaching 4 nm TOPO capped CdSe@ZnS quantum dots onto magnetite particles, altering the surface properties of quantum dots from hydrophobic to hydrophilic as well as preventing the formation of large aggregates. Results show that these water-soluble hybrid nanocomposites exhibit good colloidal stability and retain good magnetic and fluorescent properties. Because TOPO-capped QDs are assembled instead of their water-soluble equivalents, the nanocomposites are still highly luminescent with no shift in the PL peak position and present long-term fluorescence stability. Moreover, TAT peptide (GRKKRRQRRRPQ) functionalized hybrid nanoparticles were also studied due to their combined magnetic enrichment and optical detection for cell separation and rapid cell labelling. A cell viability assay revealed good biocompatibility of these hybrid nanoparticles. The potential application of the new magnetic-fluorescent nanocomposites in biological and medicine is demonstrated. PMID:21503355

  18. Magnetic resonance imaging in the evaluation of cognitive function.

    PubMed

    Bigler, Erin D

    2014-10-01

    Image quality of magnetic resonance imaging (MRI) scans of the brain currently approximate gross anatomy as would be viewed at autopsy. During the first decade of the 21st Century incredible advances in image processing and quantification have occurred permitting more refined methods for studying brain-behavior-cognitive functioning. The current presentation overviews the current status of MRI methods for routine clinical assessment of brain pathology, how these techniques identify neuropathology and how pathological findings are quantified. Diffusion tensor imaging (DTI), functional MRI (fMRI), and resting state fMRI are all reviewed, emphasizing how these techniques permit an examination of brain function and connectivity. General regional relationships of brain function associated with cognitive control will be highlighted.

  19. Advanced Morphological and Functional Magnetic Resonance Techniques in Glaucoma

    PubMed Central

    Mastropasqua, Rodolfo; Agnifili, Luca; Mattei, Peter A.; Caulo, Massimo; Fasanella, Vincenzo; Navarra, Riccardo; Mastropasqua, Leonardo; Marchini, Giorgio

    2015-01-01

    Glaucoma is a multifactorial disease that is the leading cause of irreversible blindness. Recent data documented that glaucoma is not limited to the retinal ganglion cells but that it also extends to the posterior visual pathway. The diagnosis is based on the presence of signs of glaucomatous optic neuropathy and consistent functional visual field alterations. Unfortunately these functional alterations often become evident when a significant amount of the nerve fibers that compose the optic nerve has been irreversibly lost. Advanced morphological and functional magnetic resonance (MR) techniques (morphometry, diffusion tensor imaging, arterial spin labeling, and functional connectivity) may provide a means for observing modifications induced by this fiber loss, within the optic nerve and the visual cortex, in an earlier stage. The aim of this systematic review was to determine if the use of these advanced MR techniques could offer the possibility of diagnosing glaucoma at an earlier stage than that currently possible. PMID:26167474

  20. Elucidating the Function of Penetratin and a Static Magnetic Field in Cellular Uptake of Magnetic Nanoparticles

    PubMed Central

    Chaudhary, Suman; Smith, Carol Anne; del Pino, Pablo; de la Fuente, Jesus M.; Mullin, Margaret; Hursthouse, Andrew; Stirling, David; Berry, Catherine C.

    2013-01-01

    Nanotechnology plays an increasingly important role in the biomedical arena. In particular, magnetic nanoparticles (mNPs) have become important tools in molecular diagnostics, in vivo imaging and improved treatment of disease, with the ultimate aim of producing a more theranostic approach. Due to their small sizes, the nanoparticles can cross most of the biological barriers such as the blood vessels and the blood brain barrier, thus providing ubiquitous access to most tissues. In all biomedical applications maximum nanoparticle uptake into cells is required. Two promising methods employed to this end include functionalization of mNPs with cell-penetrating peptides to promote efficient translocation of cargo into the cell and the use of external magnetic fields for enhanced delivery. This study aimed to compare the effect of both penetratin and a static magnetic field with regards to the cellular uptake of 200 nm magnetic NPs and determine the route of uptake by both methods. Results demonstrated that both techniques increased particle uptake, with penetratin proving more cell specific. Clathrin- medicated endocytosis appeared to be responsible for uptake as shown via PCR and western blot, with Pitstop 2 (known to selectively block clathrin formation) blocking particle uptake. Interestingly, it was further shown that a magnetic field was able to reverse or overcome the blocking, suggesting an alternative route of uptake. PMID:24275948

  1. The physics of functional magnetic resonance imaging (fMRI)

    NASA Astrophysics Data System (ADS)

    Buxton, Richard B.

    2013-09-01

    Functional magnetic resonance imaging (fMRI) is a methodology for detecting dynamic patterns of activity in the working human brain. Although the initial discoveries that led to fMRI are only about 20 years old, this new field has revolutionized the study of brain function. The ability to detect changes in brain activity has a biophysical basis in the magnetic properties of deoxyhemoglobin, and a physiological basis in the way blood flow increases more than oxygen metabolism when local neural activity increases. These effects translate to a subtle increase in the local magnetic resonance signal, the blood oxygenation level dependent (BOLD) effect, when neural activity increases. With current techniques, this pattern of activation can be measured with resolution approaching 1 mm3 spatially and 1 s temporally. This review focuses on the physical basis of the BOLD effect, the imaging methods used to measure it, the possible origins of the physiological effects that produce a mismatch of blood flow and oxygen metabolism during neural activation, and the mathematical models that have been developed to understand the measured signals. An overarching theme is the growing field of quantitative fMRI, in which other MRI methods are combined with BOLD methods and analyzed within a theoretical modeling framework to derive quantitative estimates of oxygen metabolism and other physiological variables. That goal is the current challenge for fMRI: to move fMRI from a mapping tool to a quantitative probe of brain physiology.

  2. The physics of functional magnetic resonance imaging (fMRI)

    PubMed Central

    Buxton, Richard B

    2015-01-01

    Functional magnetic resonance imaging (fMRI) is a methodology for detecting dynamic patterns of activity in the working human brain. Although the initial discoveries that led to fMRI are only about 20 years old, this new field has revolutionized the study of brain function. The ability to detect changes in brain activity has a biophysical basis in the magnetic properties of deoxyhemoglobin, and a physiological basis in the way blood flow increases more than oxygen metabolism when local neural activity increases. These effects translate to a subtle increase in the local magnetic resonance signal, the blood oxygenation level dependent (BOLD) effect, when neural activity increases. With current techniques, this pattern of activation can be measured with resolution approaching 1 mm3 spatially and 1 s temporally. This review focuses on the physical basis of the BOLD effect, the imaging methods used to measure it, the possible origins of the physiological effects that produce a mismatch of blood flow and oxygen metabolism during neural activation, and the mathematical models that have been developed to understand the measured signals. An overarching theme is the growing field of quantitative fMRI, in which other MRI methods are combined with BOLD methods and analyzed within a theoretical modeling framework to derive quantitative estimates of oxygen metabolism and other physiological variables. That goal is the current challenge for fMRI: to move fMRI from a mapping tool to a quantitative probe of brain physiology. PMID:24006360

  3. Nuclear chiral and magnetic rotation in covariant density functional theory

    NASA Astrophysics Data System (ADS)

    Meng, Jie; Zhao, Pengwei

    2016-05-01

    Excitations of chiral rotation observed in triaxial nuclei and magnetic and/or antimagnetic rotations (AMR) seen in near-spherical nuclei have attracted a lot of attention. Unlike conventional rotation in well-deformed or superdeformed nuclei, here the rotational axis is not necessary coinciding with any principal axis of the nuclear density distribution. Thus, tilted axis cranking (TAC) is mandatory to describe these excitations self-consistently in the framework of covariant density functional theory (CDFT). We will briefly introduce the formalism of TAC-CDFT and its application for magnetic and AMR phenomena. Configuration-fixed CDFT and its predictions for nuclear chiral configurations and for favorable triaxial deformation parameters are also presented, and the discoveries of the multiple chiral doublets in 133Ce and 103Rh are discussed.

  4. Coupled particle-fluid transport and magnetic separation in microfluidic systems with passive magnetic functionality

    NASA Astrophysics Data System (ADS)

    Khashan, Saud A.; Furlani, Edward P.

    2013-03-01

    A study is presented of coupled particle-fluid transport and field-directed particle capture in microfluidic systems with passive magnetic functionality. These systems consist of a microfluidic flow cell on a substrate that contains embedded magnetic elements. Two systems are considered that utilize soft- and hard-magnetic elements, respectively. In the former, an external field is applied to magnetize the elements, and in the latter, they are permanently magnetized. The field produced by the magnetized elements permeates into the flow cell giving rise to an attractive force on magnetic particles that flow through it. The systems are studied using a novel numerical/closed-form modelling approach that combines numerical transport analysis with closed-form field analysis. Particle-fluid transport is computed using computational fluid dynamics (CFD), while the magnetic force that governs particle capture is obtained in closed form. The CFD analysis takes into account dominant particle forces and two-way momentum transfer between the particles and the fluid. The two-way particle-fluid coupling capability is an important feature of the model that distinguishes it from more commonly used and simplified one-way coupling analysis. The model is used to quantify the impact of two-way particle-fluid coupling on both the capture efficiency and the flow pattern in the systems considered. Many effects such as particle-induced flow-enhanced capture efficiency and flow circulation are studied that cannot be predicted using one-way coupling analysis. In addition, dilute particle dispersions are shown to exhibit significant localized particle-fluid coupling near the capture regions, which contradicts the commonly held view that two-way coupling can be ignored when analysing high-gradient magnetic separation involving such particle systems. Overall, the model demonstrates that two-way coupling needs to be taken into account for rigorous predictions of capture efficiency, especially

  5. The 3T3-L1 adipocyte glycogen proteome

    PubMed Central

    2013-01-01

    Background Glycogen is a branched polysaccharide of glucose residues, consisting of α-1-4 glycosidic linkages with α-1-6 branches that together form multi-layered particles ranging in size from 30 nm to 300 nm. Glycogen spatial conformation and intracellular organization are highly regulated processes. Glycogen particles interact with their metabolizing enzymes and are associated with a variety of proteins that intervene in its biology, controlling its structure, particle size and sub-cellular distribution. The function of glycogen in adipose tissue is not well understood but appears to have a pivotal role as a regulatory mechanism informing the cells on substrate availability for triacylglycerol synthesis. To provide new molecular insights into the role of adipocyte glycogen we analyzed the glycogen-associated proteome from differentiated 3T3-L1-adipocytes. Results Glycogen particles from 3T3-L1-adipocytes were purified using a series of centrifugation steps followed by specific elution of glycogen bound proteins using α-1,4 glucose oligosaccharides, or maltodextrins, and tandem mass spectrometry. We identified regulatory proteins, 14-3-3 proteins, RACK1 and protein phosphatase 1 glycogen targeting subunit 3D. Evidence was also obtained for a regulated subcellular distribution of the glycogen particle: metabolic and mitochondrial proteins were abundant. Unlike the recently analyzed hepatic glycogen proteome, no endoplasmic proteins were detected, along with the recently described starch-binding domain protein 1. Other regulatory proteins which have previously been described as glycogen-associated proteins were not detected, including laforin, the AMPK beta-subunit and protein targeting to glycogen (PTG). Conclusions These data provide new molecular insights into the regulation of glycogen-bound proteins that are associated with the maintenance, organization and localization of the adipocyte glycogen particle. PMID:23521774

  6. Magnetic field shift due to mechanical vibration in functional magnetic resonance imaging.

    PubMed

    Foerster, Bernd U; Tomasi, Dardo; Caparelli, Elisabeth C

    2005-11-01

    Mechanical vibrations of the gradient coil system during readout in echo-planar imaging (EPI) can increase the temperature of the gradient system and alter the magnetic field distribution during functional magnetic resonance imaging (fMRI). This effect is enhanced by resonant modes of vibrations and results in apparent motion along the phase encoding direction in fMRI studies. The magnetic field drift was quantified during EPI by monitoring the resonance frequency interleaved with the EPI acquisition, and a novel method is proposed to correct the apparent motion. The knowledge on the frequency drift over time was used to correct the phase of the k-space EPI dataset. Since the resonance frequency changes very slowly over time, two measurements of the resonance frequency, immediately before and after the EPI acquisition, are sufficient to remove the field drift effects from fMRI time series. The frequency drift correction method was tested "in vivo" and compared to the standard image realignment method. The proposed method efficiently corrects spurious motion due to magnetic field drifts during fMRI.

  7. A method for functional magnetic resonance imaging of olfaction.

    PubMed

    Sobel, N; Prabhakaran, V; Desmond, J E; Glover, G H; Sullivan, E V; Gabrieli, J D

    1997-12-30

    A method for generating olfactory stimuli for humans within a functional magnetic resonance imaging (fMRI) experimental design is described. The system incorporates a nasal-mask in which the change from odorant to no-odorant conditions occurs in less than 500 ms and is not accompanied by visual, auditory, tactile, or thermal cues. The mask provides an ordorant-free environment following prolonged ordorant presence. Specific imaging parameters that are conducive to the study of the human olfactory system are described. In a pilot study performed using these methods, the specific patterns of activation observed converged with published experimental and clinical findings. PMID:9497007

  8. The economics of functional magnetic resonance imaging: clinical and research.

    PubMed

    Yousem, David M

    2014-11-01

    It is difficult to justify maintaining a clinical functional magnetic resonance imaging (fMRI) program based solely on revenue generation. The use of fMRI is, therefore, based mostly in patient care considerations, leading to better outcomes. The high costs of the top-of-the-line equipment, hardware, and software needed for state-of-the-art fMRI and the time commitment by multiple professionals are not adequately reimbursed at a representative rate by current payor schemes for the Current Procedure Terminology codes assigned.

  9. Gravitational environment produced by a superconducting magnet affects osteoblast morphology and functions

    NASA Astrophysics Data System (ADS)

    Qian, Airong; Zhang, Wei; Weng, Yuanyuan; Tian, Zongcheng; Di, Shengmeng; Yang, Pengfei; Yin, Dachuan; Hu, Lifang; Wang, Zhe; Xu, Huiyun; Shang, Peng

    The aims of this study are to investigate the effects of gravitational environment produced by a superconducting magnet on osteoblast morphology, proliferation and adhesion. A superconducting magnet which can produce large gradient high magnetic field (LGHMF) and provide three apparent gravity levels (0g,1gand2g) was employed to simulate space gravity environment. The effects of LGHMF on osteoblast morphology, proliferation, adhesion and the gene expression of fibronectin and collagen I were detected by scanning electron microscopy, immunocytochemistry, adhesion assays and real time PCR, respectively, after exposure of osteoblasts to LGHMF for 24 h. Osteoblast morphology was affected by LGHMF (0g,1gand2g) and the most evident morphology alteration was observed at 0g condition. Proliferative abilities of MC3T3 and MG-63 cell were affected under LGHMF (0g,1gand2g) conditions compared to control condition. The adhesive abilities of MC3T3 and MG-63 cells to extracellular matrix (ECM) proteins (fibronectin, laminin, collagen IV) were also affected by LGHMF (0g,1gand2g), moreover, the effects of LGHMF on osteoblast adhesion to different ECM proteins were different. Fibronectin gene expression in MG63 cells under zero gravity condition was increased significantly compared to other conditions. Collagen I gene expression in MG-63 and MC3T3 cells was altered by both magnetic field and alerted gravity. The study indicates that the superconducting magnet which can produce LGHMF may be a novel ground-based space gravity simulator and can be used for biological experiment at cellular level.

  10. Repeatability and sensitivity of T2* measurements in patients with head and neck squamous cell carcinoma at 3T

    PubMed Central

    Panek, Rafal; Welsh, Liam; Dunlop, Alex; Wong, Kee H.; Riddell, Angela M.; Koh, Dow‐Mu; Schmidt, Maria A.; Doran, Simon; Mcquaid, Dualta; Hopkinson, Georgina; Richardson, Cheryl; Nutting, Christopher M.; Bhide, Shreerang A.; Harrington, Kevin J.; Robinson, Simon P.; Newbold, Kate L.

    2016-01-01

    Purpose To determine whether quantitation of T2* is sufficiently repeatable and sensitive to detect clinically relevant oxygenation levels in head and neck squamous cell carcinoma (HNSCC) at 3T. Materials and Methods Ten patients with newly diagnosed locally advanced HNSCC underwent two magnetic resonance imaging (MRI) scans between 24 and 168 hours apart prior to chemoradiotherapy treatment. A multiple gradient echo sequence was used to calculate T2* maps. A quadratic function was used to model the blood transverse relaxation rate as a function of blood oxygenation. A set of published coefficients measured at 3T were incorporated to account for tissue hematocrit levels and used to plot the dependence of fractional blood oxygenation (Y) on T2* values, together with the corresponding repeatability range. Repeatability of T2* using Bland–Altman analysis, and calculation of limits of agreement (LoA), was used to assess the sensitivity, defined as the minimum difference in fractional blood oxygenation that can be confidently detected. Results T2* LoA for 22 outlined tumor volumes were 13%. The T2* dependence of fractional blood oxygenation increases monotonically, resulting in increasing sensitivity of the method with increasing blood oxygenation. For fractional blood oxygenation values above 0.11, changes in T2* were sufficient to detect differences in blood oxygenation greater than 10% (Δ T2* > LoA for ΔY > 0.1). Conclusion Quantitation of T2* at 3T can detect clinically relevant changes in tumor oxygenation within a wide range of blood volumes and oxygen tensions, including levels reported in HNSCC. J. Magn. Reson. Imaging 2016;44:72–80. PMID:26800280

  11. Functional imaging of the human placenta with magnetic resonance.

    PubMed

    Siauve, Nathalie; Chalouhi, Gihad E; Deloison, Benjamin; Alison, Marianne; Clement, Olivier; Ville, Yves; Salomon, Laurent J

    2015-10-01

    Abnormal placentation is responsible for most failures in pregnancy; however, an understanding of placental functions remains largely concealed from noninvasive, in vivo investigations. Magnetic resonance imaging (MRI) is safe in pregnancy for magnetic fields of up to 3 Tesla and is being used increasingly to improve the accuracy of prenatal imaging. Functional MRI (fMRI) of the placenta has not yet been validated in a clinical setting, and most data are derived from animal studies. FMRI could be used to further explore placental functions that are related to vascularization, oxygenation, and metabolism in human pregnancies by the use of various enhancement processes. Dynamic contrast-enhanced MRI is best able to quantify placental perfusion, permeability, and blood volume fractions. However, the transplacental passage of Gadolinium-based contrast agents represents a significant safety concern for this procedure in humans. There are alternative contrast agents that may be safer in pregnancy or that do not cross the placenta. Arterial spin labeling MRI relies on magnetically labeled water to quantify the blood flows within the placenta. A disadvantage of this technique is a poorer signal-to-noise ratio. Based on arterial spin labeling, placental perfusion in normal pregnancy is 176 ± 91 mL × min(-1) × 100 g(-1) and decreases in cases with intrauterine growth restriction. Blood oxygen level-dependent and oxygen-enhanced MRIs do not assess perfusion but measure the response of the placenta to changes in oxygen levels with the use of hemoglobin as an endogenous contrast agent. Diffusion-weighted imaging and intravoxel incoherent motion MRI do not require exogenous contrast agents, instead they use the movement of water molecules within tissues. The apparent diffusion coefficient and perfusion fraction are significantly lower in placentas of growth-restricted fetuses when compared with normal pregnancies. Magnetic resonance spectroscopy has the ability to extract

  12. Functional imaging of the human placenta with magnetic resonance.

    PubMed

    Siauve, Nathalie; Chalouhi, Gihad E; Deloison, Benjamin; Alison, Marianne; Clement, Olivier; Ville, Yves; Salomon, Laurent J

    2015-10-01

    Abnormal placentation is responsible for most failures in pregnancy; however, an understanding of placental functions remains largely concealed from noninvasive, in vivo investigations. Magnetic resonance imaging (MRI) is safe in pregnancy for magnetic fields of up to 3 Tesla and is being used increasingly to improve the accuracy of prenatal imaging. Functional MRI (fMRI) of the placenta has not yet been validated in a clinical setting, and most data are derived from animal studies. FMRI could be used to further explore placental functions that are related to vascularization, oxygenation, and metabolism in human pregnancies by the use of various enhancement processes. Dynamic contrast-enhanced MRI is best able to quantify placental perfusion, permeability, and blood volume fractions. However, the transplacental passage of Gadolinium-based contrast agents represents a significant safety concern for this procedure in humans. There are alternative contrast agents that may be safer in pregnancy or that do not cross the placenta. Arterial spin labeling MRI relies on magnetically labeled water to quantify the blood flows within the placenta. A disadvantage of this technique is a poorer signal-to-noise ratio. Based on arterial spin labeling, placental perfusion in normal pregnancy is 176 ± 91 mL × min(-1) × 100 g(-1) and decreases in cases with intrauterine growth restriction. Blood oxygen level-dependent and oxygen-enhanced MRIs do not assess perfusion but measure the response of the placenta to changes in oxygen levels with the use of hemoglobin as an endogenous contrast agent. Diffusion-weighted imaging and intravoxel incoherent motion MRI do not require exogenous contrast agents, instead they use the movement of water molecules within tissues. The apparent diffusion coefficient and perfusion fraction are significantly lower in placentas of growth-restricted fetuses when compared with normal pregnancies. Magnetic resonance spectroscopy has the ability to extract

  13. Approach to combined-function magnets via symplectic slicing

    NASA Astrophysics Data System (ADS)

    Titze, M.

    2016-05-01

    In this article we describe how to obtain symplectic "slice" maps for combined-function magnets, by using a method of generating functions. A feature of this method is that one can use an unexpanded and unsplit Hamiltonian. From such a slice map we obtain a first-order map which is symplectic at the closed orbit. We also obtain a symplectic kick map. Both results were implemented into the widely used program MAD-X to regain, in particular, the twiss parameters for the sliced model of the Proton Synchrotron at CERN. In addition, we obtain recursion equations for symplectic maps of general time-dependent Hamiltonians, which might be useful even beyond the scope of accelerator physics.

  14. Magnetic resonance and the human brain: anatomy, function and metabolism.

    PubMed

    Talos, I-F; Mian, A Z; Zou, K H; Hsu, L; Goldberg-Zimring, D; Haker, S; Bhagwat, J G; Mulkern, R V

    2006-05-01

    The introduction and development, over the last three decades, of magnetic resonance (MR) imaging and MR spectroscopy technology for in vivo studies of the human brain represents a truly remarkable achievement, with enormous scientific and clinical ramifications. These effectively non-invasive techniques allow for studies of the anatomy, the function and the metabolism of the living human brain. They have allowed for new understandings of how the healthy brain works and have provided insights into the mechanisms underlying multiple disease processes which affect the brain. Different MR techniques have been developed for studying anatomy, function and metabolism. The primary focus of this review is to describe these different methodologies and to briefly review how they are being employed to more fully appreciate the intricacies associated with the organ, which most distinctly differentiates the human species from the other animal forms on earth.

  15. Pulmonary functional magnetic resonance imaging for paediatric lung disease.

    PubMed

    Kirby, Miranda; Coxson, Harvey O; Parraga, Grace

    2013-09-01

    A better understanding of the anatomic structure and physiological function of the lung is fundamental to understanding the pathogenesis of pulmonary disease and how to design and deliver better treatments and measure response to intervention. Magnetic resonance imaging (MRI) with the hyperpolarised noble gases helium-3 ((3)He) and xenon-129 ((129)Xe) provides both structural and functional pulmonary measurements, and because it does not require the use of x-rays or other ionising radiation, offers the potential for intensive serial and longitudinal studies in paediatric patients. These facts are particularly important in the evaluation of chronic lung diseases such as asthma and cystic fibrosis- both of which can be considered paediatric respiratory diseases with unmet therapy needs. This review discusses MRI-based imaging methods with a focus on hyperpolarised gas MRI. We also discuss the strengths and limitations as well as the future work required for clinical translation towards paediatric respiratory disease. PMID:23522599

  16. Magnetic resonance and the human brain: anatomy, function and metabolism.

    PubMed

    Talos, I-F; Mian, A Z; Zou, K H; Hsu, L; Goldberg-Zimring, D; Haker, S; Bhagwat, J G; Mulkern, R V

    2006-05-01

    The introduction and development, over the last three decades, of magnetic resonance (MR) imaging and MR spectroscopy technology for in vivo studies of the human brain represents a truly remarkable achievement, with enormous scientific and clinical ramifications. These effectively non-invasive techniques allow for studies of the anatomy, the function and the metabolism of the living human brain. They have allowed for new understandings of how the healthy brain works and have provided insights into the mechanisms underlying multiple disease processes which affect the brain. Different MR techniques have been developed for studying anatomy, function and metabolism. The primary focus of this review is to describe these different methodologies and to briefly review how they are being employed to more fully appreciate the intricacies associated with the organ, which most distinctly differentiates the human species from the other animal forms on earth. PMID:16568243

  17. Bayesian spatiotemporal inference in functional magnetic resonance imaging.

    PubMed

    Gössl, C; Auer, D P; Fahrmeir, L

    2001-06-01

    Mapping of the human brain by means of functional magnetic resonance imaging (fMRI) is an emerging field in cognitive and clinical neuroscience. Current techniques to detect activated areas of the brain mostly proceed in two steps. First, conventional methods of correlation, regression, and time series analysis are used to assess activation by a separate, pixelwise comparison of the fMRI signal time courses to the reference function of a presented stimulus. Spatial aspects caused by correlations between neighboring pixels are considered in a separate second step, if at all. The aim of this article is to present hierarchical Bayesian approaches that allow one to simultaneously incorporate temporal and spatial dependencies between pixels directly in the model formulation. For reasons of computational feasibility, models have to be comparatively parsimonious, without oversimplifying. We introduce parametric and semiparametric spatial and spatiotemporal models that proved appropriate and illustrate their performance applied to visual fMRI data.

  18. Functional Magnetic Resonance Imaging in Acute Kidney Injury: Present Status

    PubMed Central

    Zhou, Hai Ying; Chen, Tian Wu; Zhang, Xiao Ming

    2016-01-01

    Acute kidney injury (AKI) is a common complication of hospitalization that is characterized by a sudden loss of renal excretory function and associated with the subsequent development of chronic kidney disease, poor prognosis, and increased mortality. Although the pathophysiology of renal functional impairment in the setting of AKI remains poorly understood, previous studies have identified changes in renal hemodynamics, perfusion, and oxygenation as key factors in the development and progression of AKI. The early assessment of these changes remains a challenge. Many established approaches are not applicable to humans because of their invasiveness. Functional renal magnetic resonance (MR) imaging offers an alternative assessment tool that could be used to evaluate renal morphology and function noninvasively and simultaneously. Thus, the purpose of this review is to illustrate the principle, application, and role of the techniques of functional renal MR imaging, including blood oxygen level-dependent imaging, arterial spin labeling, and diffusion-weighted MR imaging, in the management of AKI. The use of gadolinium in MR imaging may exacerbate renal impairment and cause nephrogenic systemic fibrosis. Therefore, dynamic contrast-enhanced MR imaging will not be discussed in this paper. PMID:26925411

  19. Central pain processing in chronic chemotherapy-induced peripheral neuropathy: a functional magnetic resonance imaging study.

    PubMed

    Boland, Elaine G; Selvarajah, Dinesh; Hunter, Mike; Ezaydi, Yousef; Tesfaye, Solomon; Ahmedzai, Sam H; Snowden, John A; Wilkinson, Iain D

    2014-01-01

    Life expectancy in multiple myeloma has significantly increased. However, a high incidence of chemotherapy induced peripheral neuropathy (CIPN) can negatively influence quality of life during this period. This study applied functional magnetic resonance imaging (fMRI) to compare areas associated with central pain processing in patients with multiple myeloma who had chemotherapy induced peripheral neuropathy (MM-CIPN) with those from healthy volunteers (HV). Twenty-four participants (n = 12 MM-CIPN, n = 12 HV) underwent Blood Oxygen Level-Dependent (BOLD) fMRI at 3T whilst noxious heat-pain stimuli were applied to the foot and then thigh. Patients with MM-CIPN demonstrated greater activation during painful stimulation in the precuneus compared to HV (p = 0.014, FWE-corrected). Patients with MM-CIPN exhibited hypo-activation of the right superior frontal gyrus compared to HV (p = 0.031, FWE-corrected). Significant positive correlation existed between the total neuropathy score (reduced version) and activation in the frontal operculum (close to insular cortex) during foot stimulation in patients with MM-CIPN (p = 0.03, FWE-corrected; adjusted R2 = 0.87). Painful stimuli delivered to MM-CIPN patients evoke differential activation of distinct cortical regions, reflecting a unique pattern of central pain processing compared with healthy volunteers. This characteristic activation pattern associated with pain furthers the understanding of the pathophysiology of painful chemotherapy induced peripheral neuropathy. Functional MRI provides a tool for monitoring cerebral changes during anti-cancer and analgesic treatment.

  20. Modulating functional and dysfunctional mentalizing by transcranial magnetic stimulation

    PubMed Central

    Schuwerk, Tobias; Langguth, Berthold; Sommer, Monika

    2014-01-01

    Mentalizing, the ability to attribute mental states to others and oneself, is a cognitive function with high relevance for social interactions. Recent neuroscientific research has increasingly contributed to attempts to decompose this complex social cognitive function into constituting neurocognitive building blocks. Additionally, clinical research that focuses on social cognition to find links between impaired social functioning and neurophysiological deviations has accumulated evidence that mentalizing is affected in most psychiatric disorders. Recently, both lines of research have started to employ transcranial magnetic stimulation: the first to modulate mentalizing in order to specify its neurocognitive components, the latter to treat impaired mentalizing in clinical conditions. This review integrates findings of these two different approaches to draw a more detailed picture of the neurocognitive basis of mentalizing and its deviations in psychiatric disorders. Moreover, we evaluate the effectiveness of hitherto employed stimulation techniques and protocols, paradigms and outcome measures. Based on this overview we highlight new directions for future research on the neurocognitive basis of functional and dysfunctional social cognition. PMID:25477838

  1. [Functional magnetic resonance imaging of psychopharmacological brain effects: an update].

    PubMed

    Braus, D F; Brassen, S; Weimer, E; Tost, H

    2003-02-01

    Functional magnetic resonance imaging (fMRI) is well established for the examination of functional activity in the living brain. The method permits the development of functional activation maps during perceptual, cognitive and emotional efforts with a high temporal and spatial resolution. As of late there has been growing interest in using this technique to investigate regionally specific brain activity following the administration of drugs such as nicotine, cocaine, lorazepam, scopolamine, antipsychotics or antidepressants. Studies in experimental animals investigate signal changes associated with the administration of psychopharmacological substances in different brain areas using a high magnetising field (> 4 Tesla). FMRI-studies in healthy human volunteers and psychiatric patients focus on cerebral activity following acute drug administration (single challenge) and on adaptive effects of the CNS due to long- term medication. Their results provide insights into brain physiology and neuropharmacological mechanisms which are in turn relevant for preclinical pharmacological studies, responder analyses and for the investigation of pathogenetic models in psychiatric diseases. However, with these new opportunities, additional methodological considerations and limitations emerge. Besides the need of controlling motion artefacts, the influence of interfering psychological variables, an exact specification of the experimental design, a standardised analysis for data adjustment and technical limitations have to be considered. This article provides an overview of the underlying model of brain function, present applications, future possibilities and methodological limitations of fMRI for the understanding of human psychopharmacology. PMID:12579470

  2. Longitudinal functional magnetic resonance imaging in animal models.

    PubMed

    Silva, Afonso C; Liu, Junjie V; Hirano, Yoshiyuki; Leoni, Renata F; Merkle, Hellmut; Mackel, Julie B; Zhang, Xian Feng; Nascimento, George C; Stefanovic, Bojana

    2011-01-01

    Functional magnetic resonance imaging (fMRI) has had an essential role in furthering our understanding of brain physiology and function. fMRI techniques are nowadays widely applied in neuroscience research, as well as in translational and clinical studies. The use of animal models in fMRI studies has been fundamental in helping elucidate the mechanisms of cerebral blood-flow regulation, and in the exploration of basic neuroscience questions, such as the mechanisms of perception, behavior, and cognition. Because animals are inherently non-compliant, most fMRI performed to date have required the use of anesthesia, which interferes with brain function and compromises interpretability and applicability of results to our understanding of human brain function. An alternative approach that eliminates the need for anesthesia involves training the animal to tolerate physical restraint during the data acquisition. In the present chapter, we review these two different approaches to obtaining fMRI data from animal models, with a specific focus on the acquisition of longitudinal data from the same subjects.

  3. Hyperpolarized Xenon-129 Magnetic Resonance Imaging of Functional Lung Microstructure

    NASA Astrophysics Data System (ADS)

    Dregely, Isabel

    Hyperpolarized 129Xe (HXe) is a non-invasive contrast agent for lung magnetic resonance imaging (MRI), which upon inhalation follows the functional pathway of oxygen in the lung by dissolving into lung tissue structures and entering the blood stream. HXe MRI therefore provides unique opportunities for functional lung imaging of gas exchange which occurs from alveolar air spaces across the air-blood boundary into parenchymal tissue. However challenges in acquisition speed and signal-to-noise ratio have limited the development of a HXe imaging biomarker to diagnose lung disease. This thesis addresses these challenges by introducing parallel imaging to HXe MRI. Parallel imaging requires dedicated hardware. This work describes design, implementation, and characterization of a 32-channel phased-array chest receive coil with an integrated asymmetric birdcage transmit coil tuned to the HXe resonance on a 3 Tesla MRI system. Using the newly developed human chest coil, a functional HXe imaging method, multiple exchange time xenon magnetization transfer contrast (MXTC) is implemented. MXTC dynamically encodes HXe gas exchange into the image contrast. This permits two parameters to be derived regionally which are related to gas-exchange functionality by characterizing tissue-to-alveolar-volume ratio and alveolar wall thickness in the lung parenchyma. Initial results in healthy subjects demonstrate the sensitivity of MXTC by quantifying the subtle changes in lung microstructure in response to orientation and lung inflation. Our results in subjects with lung disease show that the MXTC-derived functional tissue density parameter exhibits excellent agreement with established imaging techniques. The newly developed dynamic parameter, which characterizes the alveolar wall, was elevated in subjects with lung disease, most likely indicating parenchymal inflammation. In light of these observations we believe that MXTC has potential as a biomarker for the regional quantification of 1

  4. A General Method for Calculating the External Magnetic Field from a Cylindrical Magnetic Source using Toroidal Functions

    SciTech Connect

    J Selvaggi; S Salon; O Kwon CVK Chari

    2006-02-14

    An alternative method is developed to compute the magnetic field from a circular cylindrical magnetic source. Specifically, a Fourier series expansion whose coefficients are toroidal functions is introduced which yields an alternative to the more familiar spherical harmonic solution or the Elliptic integral solution. This alternate formulation coupled with a method called charge simulation allows one to compute the external magnetic field from an arbitrary magnetic source in terms of a toroidal expansion. This expansion is valid on any finite hypothetical external observation cylinder. In other words, the magnetic scalar potential or the magnetic field intensity is computed on a exterior cylinder which encloses the magnetic source. This method can be used to accurately compute the far field where a finite element formulation is known to be inaccurate.

  5. Monitoring fractional anisotropy in developing rabbit brain using MR diffusion tensor imaging at 3T

    NASA Astrophysics Data System (ADS)

    Jao, Jo-Chi; Yang, Yu-Ting; Hsiao, Chia-Chi; Chen, Po-Chou

    2016-03-01

    The aim of this study was to investigate the factional anisotropy (FA) in various regions of developing rabbit brain using magnetic resonance diffusion tensor imaging (MR DTI) at 3 T. A whole-body clinical MR imaging (MRI) scanner with a 15-channel high resolution knee coil was used. An echo-planar-imaging (EPI)-DTI pulse sequence was performed. Five 5 week-old New Zealand white (NZW) rabbits underwent MRI once per week for 24 weeks. After scanning, FA maps were obtained. ROIs (regions of interests) in the frontal lobe, parietal & temporal lobe, and occipital lobe were measured. FA changes with time were evaluated with a linear regression analysis. The results show that the FA values in all lobes of the brain increased linearly with age. The ranking of FA values was FA(frontal lobe) < FA(parietal & temporal lobe) > FA(occipital lobe). There was significant difference (p < 0.05) among these lobes. FA values are associated with the nerve development and brain functions. The FA change rate could be a biomarker to monitor the brain development. Understanding the FA values of various lobes during development could provide helpful information to diagnosis the abnormal syndrome earlier and have a better treatment and prognosis. This study established a brain MR-DTI protocol for rabbits to investigate the brain anatomy during development using clinical MRI. This technique can be further applied to the pre-clinical diagnosis, treatment, prognosis and follow-up of brain lesions.

  6. Simultaneous 3-T fMRI and high-density recording of human auditory evoked potentials.

    PubMed

    Scarff, Carrie J; Reynolds, Angela; Goodyear, Bradley G; Ponton, Curtis W; Dort, Joseph C; Eggermont, Jos J

    2004-11-01

    We acquired simultaneous high-field (3 T) functional magnetic resonance imaging (fMRI) and high-density (64- and 128-channel) EEG using a sparse sampling technique to measure auditory cortical activity generated by right ear stimulus presentation. Using dipole source localization, we showed that the anatomical location of the grand mean equivalent dipole of auditory evoked potentials (AEPs) and the center of gravity of fMRI activity were in good agreement in the horizontal plane. However, the grand mean equivalent dipole was located significantly superior in the cortex compared to fMRI activity. Interhemispheric asymmetry was exhibited by fMRI, whereas neither the AEP dipole moments nor the mean global field power (MGFP) of the AEPs showed significant asymmetry. Increasing the number of recording electrodes from 64 to 128 improved the accuracy of the equivalent dipole source localization but decreased the signal-to-noise ratio (SNR) of MR images. This suggests that 64 electrodes may be optimal for use in simultaneous recording of EEG and fMRI.

  7. Using High Spatial Resolution to Improve BOLD fMRI Detection at 3T

    PubMed Central

    Claise, Béatrice; Jean, Betty

    2015-01-01

    For different functional magnetic resonance imaging experiments using blood oxygenation level-dependent (BOLD) contrast, the acquisition of T2*-weighted scans at a high spatial resolution may be advantageous in terms of time-course signal-to-noise ratio and of BOLD sensitivity when the regions are prone to susceptibility artifacts. In this study, we explore this solution by examining how spatial resolution influences activations elicited when appetizing food pictures are viewed. Twenty subjects were imaged at 3 T with two different voxel volumes, 3.4 μl and 27 μl. Despite the diminution of brain coverage, we found that high-resolution acquisition led to a better detection of activations. Though known to suffer to different degrees from susceptibility artifacts, the activations detected by high spatial resolution were notably consistent with those reported in published activation likelihood estimation meta-analyses, corresponding to taste-responsive regions. Furthermore, these regions were found activated bilaterally, in contrast with previous findings. Both the reduction of partial volume effect, which improves BOLD contrast, and the mitigation of susceptibility artifact, which boosts the signal to noise ratio in certain regions, explained the better detection noted with high resolution. The present study provides further evidences that high spatial resolution is a valuable solution for human BOLD fMRI, especially for studying food-related stimuli. PMID:26550990

  8. QUANTITATIVE PLANAR AND VOLUMETRIC CARDIAC MEASUREMENTS USING 64 MDCT AND 3T MRI VS. STANDARD 2D AND M-MODE ECHOCARDIOGRAPHY: DOES ANESTHETIC PROTOCOL MATTER?

    PubMed

    Drees, Randi; Johnson, Rebecca A; Stepien, Rebecca L; Munoz Del Rio, Alejandro; Saunders, Jimmy H; François, Christopher J

    2015-01-01

    Cross-sectional imaging of the heart utilizing computed tomography and magnetic resonance imaging (MRI) has been shown to be superior for the evaluation of cardiac morphology and systolic function in humans compared to echocardiography. The purpose of this prospective study was to test the effects of two different anesthetic protocols on cardiac measurements in 10 healthy beagle dogs using 64-multidetector row computed tomographic angiography (64-MDCTA), 3T magnetic resonance (MRI) and standard awake echocardiography. Both anesthetic protocols used propofol for induction and isoflourane for anesthetic maintenance. In addition, protocol A used midazolam/fentanyl and protocol B used dexmedetomedine as premedication and constant rate infusion during the procedure. Significant elevations in systolic and mean blood pressure were present when using protocol B. There was overall good agreement between the variables of cardiac size and systolic function generated from the MDCTA and MRI exams and no significant difference was found when comparing the variables acquired using either anesthetic protocol within each modality. Systolic function variables generated using 64-MDCTA and 3T MRI were only able to predict the left ventricular end diastolic volume as measured during awake echocardiogram when using protocol B and 64-MDCTA. For all other systolic function variables, prediction of awake echocardiographic results was not possible (P = 1). Planar variables acquired using MDCTA or MRI did not allow prediction of the corresponding measurements generated using echocardiography in the awake patients (P = 1). Future studies are needed to validate this approach in a more varied population and clinically affected dogs.

  9. Unusual Function of Modified Polyolefins for Manipulating Magnetic Nanostructures

    NASA Astrophysics Data System (ADS)

    He, Qingliang; Yuan, Tingting; Wei, Suying; Guo, Zhanhu

    2014-04-01

    The unusual function of a long known plastic additive in industry, polypropylene- graft-maleic anhydride (PP- g-MA), is reviewed for serving as a polymeric surfactant to synthesize and stabilize magnetic nanoparticles (NPs) with tunable morphology and crystalline structure. The synthesis route employs a solution-based, one-pot, bottom-up method. Specifically, magnetic NPs were synthesized through thermo-decomposing organo-metallic precursors [i.e., Fe(CO)5 or Co2(CO)8] in the presence of PP- g-MA in solvent xylene. By simply changing the backbone length/concentration of PP- g-MA, different morphologies (monodispersed hollow vs. chain-like solid, or chain-like vs. monodispersed polyhedral-shaped NPs) and crystalline structures [α- vs. γ-phase for Fe2O3 NPs, or face-centered cubic (fcc)- vs. ɛ-phase for Co NPs] can be controlled simultaneously. In addition, for the chain-like Fe2O3 NPs, a different chain diameter and building block morphology can be controlled by only varying the molecular weight of PP- g-MA.

  10. Functional magnetic resonance imaging of autism spectrum disorders

    PubMed Central

    Dichter, Gabriel S.

    2012-01-01

    This review presents an overview of functional magnetic resonance imaging findings in autism spectrum disorders (ASDs), Although there is considerable heterogeneity with respect to results across studies, common themes have emerged, including: (i) hypoactivation in nodes of the “social brain” during social processing tasks, including regions within the prefrontal cortex, the posterior superior temporal sulcus, the amygdala, and the fusiform gyrus; (ii) aberrant frontostriatal activation during cognitive control tasks relevant to restricted and repetitive behaviors and interests, including regions within the dorsal prefrontal cortex and the basal ganglia; (iii) differential lateralization and activation of language processing and production regions during communication tasks; (iv) anomalous mesolimbic responses to social and nonsocial rewards; (v) task-based long-range functional hypoconnectivity and short-range hyper-connectivity; and (vi) decreased anterior-posterior functional connectivity during resting states. These findings provide mechanistic accounts of ASD pathophysiology and suggest directions for future research aimed at elucidating etiologic models and developing rationally derived and targeted treatments. PMID:23226956

  11. Functional magnetic resonance imaging: imaging techniques and contrast mechanisms.

    PubMed Central

    Howseman, A M; Bowtell, R W

    1999-01-01

    Functional magnetic resonance imaging (fMRI) is a widely used technique for generating images or maps of human brain activity. The applications of the technique are widespread in cognitive neuroscience and it is hoped they will eventually extend into clinical practice. The activation signal measured with fMRI is predicated on indirectly measuring changes in the concentration of deoxyhaemoglobin which arise from an increase in blood oxygenation in the vicinity of neuronal firing. The exact mechanisms of this blood oxygenation level dependent (BOLD) contrast are highly complex. The signal measured is dependent on both the underlying physiological events and the imaging physics. BOLD contrast, although sensitive, is not a quantifiable measure of neuronal activity. A number of different imaging techniques and parameters can be used for fMRI, the choice of which depends on the particular requirements of each functional imaging experiment. The high-speed MRI technique, echo-planar imaging provides the basis for most fMRI experiments. The problems inherent to this method and the ways in which these may be overcome are particularly important in the move towards performing functional studies on higher field MRI systems. Future developments in techniques and hardware are also likely to enhance the measurement of brain activity using MRI. PMID:10466145

  12. Functional magnetic resonance imaging of autism spectrum disorders.

    PubMed

    Dichter, Gabriel S

    2012-09-01

    This review presents an overview of functional magnetic resonance imaging findings in autism spectrum disorders (ASDS), although there is considerable heterogeneity with respect to results across studies, common themes have emerged, including: (i) hypoactivation in nodes of the "social brain" during social processing tasks, including regions within the prefrontal cortex, the posterior superior temporal sulcus, the amygdala, and the fusiform gyrus; (ii) aberrant frontostriatal activation during cognitive control tasks relevant to restricted and repetitive behaviors and interests, including regions within the dorsal prefrontal cortex and the basal ganglia; (iii) differential lateralization and activation of language processing and production regions during communication tasks; (iv) anomalous mesolimbic responses to social and nonsocial rewards; (v) task-based long-range functional hypoconnectivity and short-range hyper-connectivity; and (vi) decreased anterior-posterior functional connectivity during resting states. These findings provide mechanistic accounts of ASD pathophysiology and suggest directions for future research aimed at elucidating etiologic models and developing rationally derived and targeted treatments.

  13. Functional magnetic resonance imaging in chronic ischaemic stroke.

    PubMed

    Lake, Evelyn M R; Bazzigaluppi, Paolo; Stefanovic, Bojana

    2016-10-01

    Ischaemic stroke is the leading cause of adult disability worldwide. Effective rehabilitation is hindered by uncertainty surrounding the underlying mechanisms that govern long-term ischaemic injury progression. Despite its potential as a sensitive non-invasive in vivo marker of brain function that may aid in the development of new treatments, blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) has found limited application in the clinical research on chronic stage stroke progression. Stroke affects each of the physiological parameters underlying the BOLD contrast, markedly complicating the interpretation of BOLD fMRI data. This review summarizes current progress on application of BOLD fMRI in the chronic stage of ischaemic injury progression and discusses means by which more information may be gained from such BOLD fMRI measurements. Concomitant measurements of vascular reactivity, neuronal activity and metabolism in preclinical models of stroke are reviewed along with illustrative examples of post-ischaemic evolution in neuronal, glial and vascular function. The realization of the BOLD fMRI potential to propel stroke research is predicated on the carefully designed preclinical research establishing an ischaemia-specific quantitative model of BOLD signal contrast to provide the framework for interpretation of fMRI findings in clinical populations.This article is part of the themed issue 'Interpreting BOLD: a dialogue between cognitive and cellular neuroscience'.

  14. Functional magnetic resonance imaging in chronic ischaemic stroke.

    PubMed

    Lake, Evelyn M R; Bazzigaluppi, Paolo; Stefanovic, Bojana

    2016-10-01

    Ischaemic stroke is the leading cause of adult disability worldwide. Effective rehabilitation is hindered by uncertainty surrounding the underlying mechanisms that govern long-term ischaemic injury progression. Despite its potential as a sensitive non-invasive in vivo marker of brain function that may aid in the development of new treatments, blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) has found limited application in the clinical research on chronic stage stroke progression. Stroke affects each of the physiological parameters underlying the BOLD contrast, markedly complicating the interpretation of BOLD fMRI data. This review summarizes current progress on application of BOLD fMRI in the chronic stage of ischaemic injury progression and discusses means by which more information may be gained from such BOLD fMRI measurements. Concomitant measurements of vascular reactivity, neuronal activity and metabolism in preclinical models of stroke are reviewed along with illustrative examples of post-ischaemic evolution in neuronal, glial and vascular function. The realization of the BOLD fMRI potential to propel stroke research is predicated on the carefully designed preclinical research establishing an ischaemia-specific quantitative model of BOLD signal contrast to provide the framework for interpretation of fMRI findings in clinical populations.This article is part of the themed issue 'Interpreting BOLD: a dialogue between cognitive and cellular neuroscience'. PMID:27574307

  15. Surface functionalized magnetic nanoparticles for cancer therapy applications

    NASA Astrophysics Data System (ADS)

    Wydra, Robert John

    Despite recent advances, cancer remains the second leading cause of deaths in the United States. Magnetic nanoparticles have found various applications in cancer research as drug delivery platforms, enhanced contrast agents for improved diagnostic imaging, and the delivery of thermal energy as standalone therapy. Iron oxide nanoparticles absorb the energy from an alternating magnetic field and convert it into heat through Brownian and Neel relaxations. To better utilize magnetic nanoparticles for cancer therapy, surface functionalization is essential for such factors as decreasing cytotoxicity of healthy tissue, extending circulation time, specific targeting of cancer cells, and manage the controlled delivery of therapeutics. In the first study, iron oxide nanoparticles were coated with a poly(ethylene glycol) (PEG) based polymer shell. The PEG coating was selected to prevent protein adsorption and thus improve circulation time and minimize host response to the nanoparticles. Thermal therapy application feasibility was demonstrated in vitro with a thermoablation study on lung carcinoma cells. Building on the thermal therapy demonstration with iron oxide nanoparticles, the second area of work focused on intracellular delivery. Nanoparticles can be appropriately tailored to enter the cell and deliver energy on the nanoscale eliminating individual cancer cells. The underlying mechanism of action is still under study, and we were interested in determining the role of reactive oxygen species (ROS) catalytically generated from the surface of iron oxide nanoparticles in this measured cytotoxicity. When exposed to an AMF, the nanoscale heating effects are capable of enhancing the Fenton-like generation of ROS determined through a methylene blue degradation assay. To deliver this enhanced ROS effect to cells, monosaccharide coated nanoparticles were developed and successfully internalized by colon cancer cell lines. Upon AMF exposure, there was a measured increase in

  16. Achromatic synesthesias - a functional magnetic resonance imaging study.

    PubMed

    Melero, H; Ríos-Lago, M; Peña-Melián, A; Álvarez-Linera, J

    2014-09-01

    Grapheme-color synesthetes experience consistent, automatic and idiosyncratic colors associated with specific letters and numbers. Frequently, these specific associations exhibit achromatic synesthetic qualities (e.g. white, black or gray). In this study, we have investigated for the first time the neural basis of achromatic synesthesias, their relationship to chromatic synesthesias and the achromatic congruency effect in order to understand not only synesthetic color but also other components of the synesthetic experience. To achieve this aim, functional magnetic resonance imaging experiments were performed in a group of associator grapheme-color synesthetes and matched controls who were stimulated with real chromatic and achromatic stimuli (Mondrians), and with letters and numbers that elicited different types of grapheme-color synesthesias (i.e. chromatic and achromatic inducers which elicited chromatic but also achromatic synesthesias, as well as congruent and incongruent ones). The information derived from the analysis of Mondrians and chromatic/achromatic synesthesias suggests that real and synesthetic colors/achromaticity do not fully share neural mechanisms. The whole-brain analysis of BOLD signals in response to the complete set of synesthetic inducers revealed that the functional peculiarities of the synesthetic brain are distributed, and reflect different components of the synesthetic experience: a perceptual component, an (attentional) feature binding component, and an emotional component. Additionally, the inclusion of achromatic experiences has provided new evidence in favor of the emotional binding theory, a line of interpretation which constitutes a bridge between grapheme-color synesthesia and other developmental modalities of the phenomenon.

  17. Functional magnetic resonance imaging (FMRI) and expert testimony.

    PubMed

    Kulich, Ronald; Maciewicz, Raymond; Scrivani, Steven J

    2009-03-01

    Medical experts frequently use imaging studies to illustrate points in their court testimony. This article reviews how these studies impact the credibility of expert testimony with judges and juries. The apparent "objective" evidence provided by such imaging studies can lend strong credence to a judge's or jury's appraisal of medical expert's testimony. However, as the court usually has no specialized scientific expertise, the use of complex images as part of courtroom testimony also has the potential to mislead or at least inappropriately bias the weight given to expert evidence. Recent advances in brain imaging may profoundly impact forensic expert testimony. Functional magnetic resonance imaging and other physiologic imaging techniques currently allow visualization of the activation pattern of brain regions associated with a wide variety of cognitive and behavioral tasks, and more recently, pain. While functional imaging technology has a valuable role in brain research and clinical investigation, it is important to emphasize that the use of imaging studies in forensic matters requires a careful scientific foundation and a rigorous legal assessment. PMID:19254335

  18. Achromatic synesthesias - a functional magnetic resonance imaging study.

    PubMed

    Melero, H; Ríos-Lago, M; Peña-Melián, A; Álvarez-Linera, J

    2014-09-01

    Grapheme-color synesthetes experience consistent, automatic and idiosyncratic colors associated with specific letters and numbers. Frequently, these specific associations exhibit achromatic synesthetic qualities (e.g. white, black or gray). In this study, we have investigated for the first time the neural basis of achromatic synesthesias, their relationship to chromatic synesthesias and the achromatic congruency effect in order to understand not only synesthetic color but also other components of the synesthetic experience. To achieve this aim, functional magnetic resonance imaging experiments were performed in a group of associator grapheme-color synesthetes and matched controls who were stimulated with real chromatic and achromatic stimuli (Mondrians), and with letters and numbers that elicited different types of grapheme-color synesthesias (i.e. chromatic and achromatic inducers which elicited chromatic but also achromatic synesthesias, as well as congruent and incongruent ones). The information derived from the analysis of Mondrians and chromatic/achromatic synesthesias suggests that real and synesthetic colors/achromaticity do not fully share neural mechanisms. The whole-brain analysis of BOLD signals in response to the complete set of synesthetic inducers revealed that the functional peculiarities of the synesthetic brain are distributed, and reflect different components of the synesthetic experience: a perceptual component, an (attentional) feature binding component, and an emotional component. Additionally, the inclusion of achromatic experiences has provided new evidence in favor of the emotional binding theory, a line of interpretation which constitutes a bridge between grapheme-color synesthesia and other developmental modalities of the phenomenon. PMID:24845620

  19. Methodological challenges and solutions in auditory functional magnetic resonance imaging.

    PubMed

    Peelle, Jonathan E

    2014-01-01

    Functional magnetic resonance imaging (fMRI) studies involve substantial acoustic noise. This review covers the difficulties posed by such noise for auditory neuroscience, as well as a number of possible solutions that have emerged. Acoustic noise can affect the processing of auditory stimuli by making them inaudible or unintelligible, and can result in reduced sensitivity to auditory activation in auditory cortex. Equally importantly, acoustic noise may also lead to increased listening effort, meaning that even when auditory stimuli are perceived, neural processing may differ from when the same stimuli are presented in quiet. These and other challenges have motivated a number of approaches for collecting auditory fMRI data. Although using a continuous echoplanar imaging (EPI) sequence provides high quality imaging data, these data may also be contaminated by background acoustic noise. Traditional sparse imaging has the advantage of avoiding acoustic noise during stimulus presentation, but at a cost of reduced temporal resolution. Recently, three classes of techniques have been developed to circumvent these limitations. The first is Interleaved Silent Steady State (ISSS) imaging, a variation of sparse imaging that involves collecting multiple volumes following a silent period while maintaining steady-state longitudinal magnetization. The second involves active noise control to limit the impact of acoustic scanner noise. Finally, novel MRI sequences that reduce the amount of acoustic noise produced during fMRI make the use of continuous scanning a more practical option. Together these advances provide unprecedented opportunities for researchers to collect high-quality data of hemodynamic responses to auditory stimuli using fMRI. PMID:25191218

  20. An oculomotor decision process revealed by functional magnetic resonance imaging.

    PubMed

    Heinen, Stephen J; Rowland, Jess; Lee, Byeong-Taek; Wade, Alex R

    2006-12-27

    It is not known how the brain decides to act on moving objects. We demonstrated previously that neurons in the macaque supplementary eye field (SEF) reflect the rule of ocular baseball, a go/nogo task in which eye movements signal the rule-guided interpretation of the trajectory of a target. In ocular baseball, subjects must decide whether to pursue a moving spot target with an eye movement after discriminating whether the target will cross a distal, visible line segment. Here we identify cortical regions active during the ocular baseball task using event-related human functional magnetic resonance imaging (fMRI) and concurrent eye-movement monitoring. Task-related activity was observed in the SEF, the frontal eye field (FEF), the superior parietal lobule (SPL), and the right ventrolateral prefrontal cortex (VLPFC). The SPL and right VLPFC showed heightened activity only during ocular baseball, despite identical stimuli and oculomotor demands in the control task, implicating these areas in the decision process. Furthermore, the right VLPFC but not the SPL showed the greatest activation during the nogo decision trials. This suggests both a functional dissociation between these areas and a role for the right VLPFC in rule-guided inhibition of behavior. In the SEF and FEF, activity was similar for ocular baseball and a control eye-movement task. We propose that, although the SEF reflects the ocular baseball rule, both areas in humans are functionally closer to motor processing than the SPL and the right VLPFC. By recording population activity with fMRI during the ocular baseball task, we have revealed the cortical substrate of an oculomotor decision process.

  1. Multi-Parametric Neuroimaging Reproducibility: A 3T Resource Study

    PubMed Central

    Landman, Bennett A.; Huang, Alan J.; Gifford, Aliya; Vikram, Deepti S.; Lim, Issel Anne L.; Farrell, Jonathan A.D.; Bogovic, John A.; Hua, Jun; Chen, Min; Jarso, Samson; Smith, Seth A.; Joel, Suresh; Mori, Susumu; Pekar, James J.; Barker, Peter B.; Prince, Jerry L.; van Zijl, Peter C.M.

    2010-01-01

    Modern MRI image processing methods have yielded quantitative, morphometric, functional, and structural assessments of the human brain. These analyses typically exploit carefully optimized protocols for specific imaging targets. Algorithm investigators have several excellent public data resources to use to test, develop, and optimize their methods. Recently, there has been an increasing focus on combining MRI protocols in multi-parametric studies. Notably, these have included innovative approaches for fusing connectivity inferences with functional and/or anatomical characterizations. Yet, validation of the reproducibility of these interesting and novel methods has been severely hampered by the limited availability of appropriate multi-parametric data. We present an imaging protocol optimized to include state-of-the-art assessment of brain function, structure, micro-architecture, and quantitative parameters within a clinically feasible 60 minute protocol on a 3T MRI scanner. We present scan-rescan reproducibility of these imaging contrasts based on 21 healthy volunteers (11 M/10 F, 22–61 y/o). The cortical gray matter, cortical white matter, ventricular cerebrospinal fluid, thalamus, putamen, caudate, cerebellar gray matter, cerebellar white matter, and brainstem were identified with mean volume-wise reproducibility of 3.5%. We tabulate the mean intensity, variability and reproducibility of each contrast in a region of interest approach, which is essential for prospective study planning and retrospective power analysis considerations. Anatomy was highly consistent on structural acquisition (~1–5% variability), while variation on diffusion and several other quantitative scans was higher (~<10%). Some sequences are particularly variable in specific structures (ASL exhibited variation of 28% in the cerebral white matter) or in thin structures (quantitative T2 varied by up to 73% in the caudate) due, in large part, to variability in automated ROI placement. The

  2. [Magnetic micro-/nano-materials: functionalization and their applications in pretreatment for food samples].

    PubMed

    Gao, Qiang; Feng, Yuqi

    2014-10-01

    Magnetic solid phase extraction technique, based on functional magnetic materials, is currently a hot topic in the separation and analysis of complex samples. This paper reviews the reported methods for the functionalization of magnetic micro-/nano-materials, such as sur- face grafting organic groups, coating carbon or inorganic oxide, grafting or coating polymer, being loaded to the surface or pores of supports, being introduced into the skeleton of sup- ports, and physically co-mixing methods. Moreover, we briefly introduce the applications of the functional magnetic micro-/nano-materials in pretreatment for food samples.

  3. Mapping Depression in Schizophrenia: A Functional Magnetic Resonance Imaging Study.

    PubMed

    Kumari, Veena; Peters, Emmanuelle; Guinn, Ashley; Fannon, Dominic; Russell, Tamara; Sumich, Alexander; Kuipers, Elizabeth; Williams, Steven C R; Ffytche, Dominic H

    2016-05-01

    Depressive symptoms are common in schizophrenia, often left untreated, and associated with a high relapse rate, suicidal ideation, increased mortality, reduced social adjustment and poor quality of life. The neural mechanisms underlying depression in psychosis are poorly understood. Given reports of altered brain response to negative facial affect in depressive disorders, we examined brain response to emotive facial expressions in relation to levels of depression in people with psychosis. Seventy outpatients (final N= 63) and 20 healthy participants underwent functional magnetic resonance imaging during an implicit affect processing task involving presentation of facial expressions of fear, anger, happiness as well as neutral expressions and a (no face) control condition. All patients completed Beck Depression Inventory (BDI-II) and had their symptoms assessed on the Positive and Negative Syndrome Scale (PANSS). In patients, depression (BDI-II) scores associated positively with activation of the left thalamus, extending to the putamen-globus pallidus, insula, inferior-middle frontal and para-post-pre-central gyri during fearful expressions. Furthermore, patients with moderate-to-severe depression had significantly higher activity in these brain regions during fearful expressions relative to patients with no, minimal, or mild depression and healthy participants. The study provides first evidence of enhanced brain response to fearful facial expressions, which signal an uncertain source of threat in the environment, in patients with psychosis and a high level of self-reported depression. PMID:26712855

  4. Mapping Depression in Schizophrenia: A Functional Magnetic Resonance Imaging Study

    PubMed Central

    Kumari, Veena; Peters, Emmanuelle; Guinn, Ashley; Fannon, Dominic; Russell, Tamara; Sumich, Alexander; Kuipers, Elizabeth; Williams, Steven C. R.; ffytche, Dominic H.

    2016-01-01

    Depressive symptoms are common in schizophrenia, often left untreated, and associated with a high relapse rate, suicidal ideation, increased mortality, reduced social adjustment and poor quality of life. The neural mechanisms underlying depression in psychosis are poorly understood. Given reports of altered brain response to negative facial affect in depressive disorders, we examined brain response to emotive facial expressions in relation to levels of depression in people with psychosis. Seventy outpatients (final N = 63) and 20 healthy participants underwent functional magnetic resonance imaging during an implicit affect processing task involving presentation of facial expressions of fear, anger, happiness as well as neutral expressions and a (no face) control condition. All patients completed Beck Depression Inventory (BDI-II) and had their symptoms assessed on the Positive and Negative Syndrome Scale (PANSS). In patients, depression (BDI-II) scores associated positively with activation of the left thalamus, extending to the putamen-globus pallidus, insula, inferior-middle frontal and para-post-pre-central gyri during fearful expressions. Furthermore, patients with moderate-to-severe depression had significantly higher activity in these brain regions during fearful expressions relative to patients with no, minimal, or mild depression and healthy participants. The study provides first evidence of enhanced brain response to fearful facial expressions, which signal an uncertain source of threat in the environment, in patients with psychosis and a high level of self-reported depression. PMID:26712855

  5. [Functional magnetic resonance imaging and dynamic neuroanatomy of addictive disorders].

    PubMed

    Mel'nikov, M E; Shtark, M B

    2014-01-01

    Research into the cerebral patterns that govern the formation and development of addictive behavior is one of the most interesting goals of neurophysiology. Authors of contemporary papers on the matter define a number of symptoms that are all part of substance or non-substance dependence, each one of them leading to abnormalities in the corresponding system of the brain. During the last twenty years the functional magnetic resonance imaging (fMR1) technology has been instrumental in locating such abnormalities, identifying specific parts of the brain that, when dysfunctional, may enhance addiction and cause its positive or negative symptoms. This article reviews fMRI studies aimed toward locating areas in the brain that are responsible for cognitive, emotional, and motivational dysfunction. Cerebral correlatives of impulsiveness, behavior control, and drug cravings are reviewed separately. The article also contains an overview of possibilities to further investigate the Selves of those dependent on substances, identify previously unknown diagnostic markers of substance dependence, and evaluate the effectiveness of therapy. The research under review in this article provides data that points to a special role of the nucleus caudatus as well as the nucleus accumbens, the thalamus, the insular cortex (IC), the anterior cingulate, prefrontal and orbitofrontal areas in psychological disorders that are part of substance dependence. General findings of the article are in accordance with contemporary models of addictive pattern. PMID:25729844

  6. Fundamentals of electroencefalography, magnetoencefalography, and functional magnetic resonance imaging.

    PubMed

    Babiloni, Claudio; Pizzella, Vittorio; Gratta, Cosimo Del; Ferretti, Antonio; Romani, Gian Luca

    2009-01-01

    This review introduces readers to fundamentals of electroencephalography (EEG), magnetoencephalography (MEG), and functional magnetic resonance imaging (fMRI). EEG and MEG signals are mainly produced by postsynaptic ionic currents of synchronically active pyramidal cortical neurons. These signals reflect the integrative information processing of neurons representing the output of cortical neural modules. EEG and MEG signals have a high temporal resolution (<1ms) ideal to investigate an emerging propriety of brain physiology, namely the brain rhythms. A background spontaneous oscillatory activity of brain neurons at about 10Hz generates dominant alpha rhythms of resting-state EEG and MEG activity. This background activity is blocked during sensory and cognitive-motor events. Standard EEG shows a low spatial resolution (5-9cm), which partially improves by high-resolution EEG including 64-128 channels and source estimation techniques (1-3cm); source estimation of MEG data shows a better spatial resolution (0.5-2cm). fMRI is an indirect measurement of regional brain activity based on the ratio between deoxyhemoglobin and oxyhemoglobin blood (BOLD) during events referenced to baseline conditions. Event-related BOLD response has low temporal resolution (>1s) and quite high spatial resolution (<1cm), and is especially suitable to investigate spatial details of both cortical and subcortical activation.

  7. [Functional magnetic resonance imaging and dynamic neuroanatomy of addictive disorders].

    PubMed

    Mel'nikov, M E; Shtark, M B

    2014-01-01

    Research into the cerebral patterns that govern the formation and development of addictive behavior is one of the most interesting goals of neurophysiology. Authors of contemporary papers on the matter define a number of symptoms that are all part of substance or non-substance dependence, each one of them leading to abnormalities in the corresponding system of the brain. During the last twenty years the functional magnetic resonance imaging (fMR1) technology has been instrumental in locating such abnormalities, identifying specific parts of the brain that, when dysfunctional, may enhance addiction and cause its positive or negative symptoms. This article reviews fMRI studies aimed toward locating areas in the brain that are responsible for cognitive, emotional, and motivational dysfunction. Cerebral correlatives of impulsiveness, behavior control, and drug cravings are reviewed separately. The article also contains an overview of possibilities to further investigate the Selves of those dependent on substances, identify previously unknown diagnostic markers of substance dependence, and evaluate the effectiveness of therapy. The research under review in this article provides data that points to a special role of the nucleus caudatus as well as the nucleus accumbens, the thalamus, the insular cortex (IC), the anterior cingulate, prefrontal and orbitofrontal areas in psychological disorders that are part of substance dependence. General findings of the article are in accordance with contemporary models of addictive pattern.

  8. Multi-function magnetic jack control drive mechanism

    DOEpatents

    Bollinger, L.R.; Crawford, D.C.

    1983-10-06

    A multi-function magnetic jack control drive mechanism for controlling a nuclear reactor is provided. The mechanism includes an elongate pressure housing in which a plurality of closely spaced drive rods are located. Each drive rod is connected to a rod which is insertable in the reactor core. An electromechanical stationary latch device is provided which is actuatable to hold each drive rod stationary with respect to the pressure housing. An electromechanical movable latch device is also provided for each one of the drive rods. Each movable latch device is provided with a base and is actuatable to hold a respective drive rod stationary with respect to the base. An electromechanical lift device is further provided for each base which is actuatable for moving a respective base longitudinally along the pressure housing. In this manner, one or more drive rods can be moved in the pressure housing by sequentially and repetitively operating the electromechanical devices. Preferably, each latch device includes a pair of opposed latches which grip teeth located on the respective drive rod. Two, three, or four drive rods can be located symmetrically about the longitudinal axis of the pressure housing.

  9. Multi-function magnetic jack control drive mechanism

    DOEpatents

    Bollinger, Lawrence R.; Crawford, Donald C.

    1986-01-01

    A multi-function magnetic jack control drive mechanism for controlling a nuclear reactor is provided. The mechanism includes an elongate pressure housing in which a plurality of closely spaced drive rods are located. Each drive rod is connected to a rod which is insertable in the reactor core. An electromechanical stationary latch device is provided which is actuatable to hold each drive rod stationary with respect to the pressure housing. An electromechanical movable latch device is also provided for each one of the drive rods. Each movable latch device is provided with a base and is actuatable to hold a respective drive rod stationary with respect to the base. An electromechanical lift device is further provided for each base which is actuatable for moving a respective base longitudinally along the pressure housing. In this manner, one or more drive rods can be moved in the pressure housing by sequentially and repetitively operating the electromechanical devices. Preferably, each latch device includes a pair of opposed latches which grip teeth located on the respective drive rod. Two, three, or four drive rods can be located symmetrically about the longitudinal axis of the pressure housing.

  10. Functional magnetic resonance imaging of internet addiction in young adults

    PubMed Central

    Sepede, Gianna; Tavino, Margherita; Santacroce, Rita; Fiori, Federica; Salerno, Rosa Maria; Di Giannantonio, Massimo

    2016-01-01

    AIM: To report the results of functional magnetic resonance imaging (fMRI) studies pertaining internet addiction disorder (IAD) in young adults. METHODS: We conducted a systematic review on PubMed, focusing our attention on fMRI studies involving adult IAD patients, free from any comorbid psychiatric condition. The following search words were used, both alone and in combination: fMRI, internet addiction, internet dependence, functional neuroimaging. The search was conducted on April 20th, 2015 and yielded 58 records. Inclusion criteria were the following: Articles written in English, patients’ age ≥ 18 years, patients affected by IAD, studies providing fMRI results during resting state or cognitive/emotional paradigms. Structural MRI studies, functional imaging techniques other than fMRI, studies involving adolescents, patients with comorbid psychiatric, neurological or medical conditions were excluded. By reading titles and abstracts, we excluded 30 records. By reading the full texts of the 28 remaining articles, we identified 18 papers meeting our inclusion criteria and therefore included in the qualitative synthesis. RESULTS: We found 18 studies fulfilling our inclusion criteria, 17 of them conducted in Asia, and including a total number of 666 tested subjects. The included studies reported data acquired during resting state or different paradigms, such as cue-reactivity, guessing or cognitive control tasks. The enrolled patients were usually males (95.4%) and very young (21-25 years). The most represented IAD subtype, reported in more than 85% of patients, was the internet gaming disorder, or videogame addiction. In the resting state studies, the more relevant abnormalities were localized in the superior temporal gyrus, limbic, medial frontal and parietal regions. When analyzing the task related fmri studies, we found that less than half of the papers reported behavioral differences between patients and normal controls, but all of them found significant

  11. Cerebellum and speech perception: a functional magnetic resonance imaging study.

    PubMed

    Mathiak, Klaus; Hertrich, Ingo; Grodd, Wolfgang; Ackermann, Hermann

    2002-08-15

    A variety of data indicate that the cerebellum participates in perceptual tasks requiring the precise representation of temporal information. Access to the word form of a lexical item requires, among other functions, the processing of durational parameters of verbal utterances. Therefore, cerebellar dysfunctions must be expected to impair word recognition. In order to specify the topography of the assumed cerebellar speech perception mechanism, a functional magnetic resonance imaging study was performed using the German lexical items "Boden" ([bodn], Engl. "floor") and "Boten" ([botn], "messengers") as test materials. The contrast in sound structure of these two lexical items can be signaled either by the length of the wordmedial pause (closure time, CLT; an exclusively temporal measure) or by the aspiration noise of wordmedial "d" or "t" (voice onset time, VOT; an intrasegmental cue). A previous study found bilateral cerebellar disorders to compromise word recognition based on CLT whereas the encoding of VOT remained unimpaired. In the present study, two series of "Boden - Boten" utterances were resynthesized, systematically varying either in CLT or VOT. Subjects had to identify both words "Boden" and "Boten" by analysis of either the durational parameter CLT or the VOT aspiration segment. In a subtraction design, CLT categorization as compared to VOT identification (CLT - VOT) yielded a significant hemodynamic response of the right cerebellar hemisphere (neocerebellum Crus I) and the frontal lobe (anterior to Broca's area). The reversed contrast ( VOT - CLT) resulted in a single activation cluster located at the level of the supratemporal plane of the dominant hemisphere. These findings provide first evidence for a distinct contribution of the right cerebellar hemisphere to speech perception in terms of encoding of durational parameters of verbal utterances. Verbal working memory tasks, lexical response selection, and auditory imagery of word strings have been

  12. Bilingual brain organization: a functional magnetic resonance adaptation study.

    PubMed

    Klein, Denise; Zatorre, Robert J; Chen, Jen-Kai; Milner, Brenda; Crane, Joelle; Belin, Pascal; Bouffard, Marc

    2006-05-15

    We used functional magnetic resonance adaptation (fMRA) to examine whether intra-voxel functional specificity may be present for first (L1)- and second (L2)-language processing. We examined within- and across-language adaptation for spoken words in English-French bilinguals who had acquired their L2 after the age of 4 years. Subjects listened to words presented binaurally through earphones. In two control conditions (one for each language), six identical words were presented to obtain maximal adaptation. The remaining six conditions each consisted of five words that were identical followed by a sixth word that differed. There were thus a total of eight experimental conditions: no-change (sixth word identical to first five); a change in meaning (different final word in L1); a change in language (final item translated into L2); a change in meaning and language (different final word in L2). The same four conditions were presented in L2. The study also included a silent baseline. At the neural level, within- and across-language word changes resulted in release from adaptation. This was true for separate analyses of L1 and L2. We saw no evidence for greater recovery from adaptation in across-language relative to within-language conditions. While many brain regions were common to L1 and L2, we did observe differences in adaptation for forward translation (L1 to L2) as compared to backward translation (L2 to L1). The results support the idea that, at the lexical level, the neural substrates for L1 and L2 in bilinguals are shared, but with some populations of neurons within these shared regions showing language-specific responses.

  13. Dissociations between behavioural and functional magnetic resonance imaging-based evaluations of cognitive function after brain injury.

    PubMed

    Bardin, Jonathan C; Fins, Joseph J; Katz, Douglas I; Hersh, Jennifer; Heier, Linda A; Tabelow, Karsten; Dyke, Jonathan P; Ballon, Douglas J; Schiff, Nicholas D; Voss, Henning U

    2011-03-01

    Functional neuroimaging methods hold promise for the identification of cognitive function and communication capacity in some severely brain-injured patients who may not retain sufficient motor function to demonstrate their abilities. We studied seven severely brain-injured patients and a control group of 14 subjects using a novel hierarchical functional magnetic resonance imaging assessment utilizing mental imagery responses. Whereas the control group showed consistent and accurate (for communication) blood-oxygen-level-dependent responses without exception, the brain-injured subjects showed a wide variation in the correlation of blood-oxygen-level-dependent responses and overt behavioural responses. Specifically, the brain-injured subjects dissociated bedside and functional magnetic resonance imaging-based command following and communication capabilities. These observations reveal significant challenges in developing validated functional magnetic resonance imaging-based methods for clinical use and raise interesting questions about underlying brain function assayed using these methods in brain-injured subjects.

  14. A time-dependent density functional theory investigation on the nature of the electronic transitions involved in the nonlinear optical response of [Ru(CF3CO2)3T] (T = 4'-(C6H4-p-NBu2)-2,2':6',2''-terpyridine).

    PubMed

    De Angelis, Filippo; Fantacci, Simona; Sgamelotti, Antonio; Cariati, Franco; Roberto, Dominique; Tessore, Francesca; Ugo, Renato

    2006-02-14

    We report a theoretical study based on density functional theory (DFT) and time-dependent DFT (TDDFT) calculations on the nature and role of the absorption bands involved in the nonlinear optical response of the complexes [Ru(CF3CO2)3T] (T = T1, T2; T1 = 4'-(C6H4-p-NBu2)-2,2':6',2''-terpyridine, T2 = 4'-(C6H4-p-NMe2)-2,2':6',2''-terpyridine). Geometry optimizations, performed without any symmetry constraints, confirm a twisting of the -C6H4-p-NBu2 moiety with respect to the plane of the chelated terpyridine. Despite this lack of strong pi interaction, TDDFT excited states calculations of the electronic spectrum in solution provide evidence of a relevant role of the NBu2 donor group in the low-energy LMCT band at 911 nm. Calculations also show that the two bands at higher energy (508 and 455 nm) are not attributable only to LMCT and ILCT transitions but to a mixing of ILCT/MLCT and ILCT/pi-pi* transitions, respectively. The 911 nm LMCT band, appearing at lower wavelength of the second harmonic (670 nm) of the EFISH experiment, controls the negative value of the second-order NLO response. This is confirmed by our calculations of the static component beta0(zzz) of the quadratic hyperpolarizability tensor, showing a large positive value. In addition we have found that the increase of the dipole moment upon excitation occurs, in all the characterized transitions, along the dipole moment axis, thus explaining why the EFISH and solvatochromic experimental values of the quadratic hyperpolarizability agree as sign and value. PMID:16437181

  15. Studies in nonlinear optics and functional magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Dai, Tehui

    There are two parts in this thesis. The first part will involve a study in the anomalous dispersion phase matched second-harmonic generation, and the second part will be a study in functional magnetic resonance imaging (fMRI) and a biophysical model of the human muscle. In part I, we report on a series of tricyanovinylaniline chromophores for use as dopants in poled poly(methyl methacrylate) waveguides for anomalous-dispersion phase- matched second-harmonic generation. Second-harmonic generation measurements as a function of mode index confirmed anomalous dispersion phase-matching efficiencies as large as 245%/Wcm2 over a propagation length of ~35 μm. The waveguide coupling technique limited the interaction length. The photostability of the chromophores was measured directly and found to agree qualitatively with second-harmonic measurements over time and was found to be improved over previously reported materials. In part II, we designed a system that could record joint force and surface electromyography (EMG) simultaneously with fMRI data. I-Egh quality force and EMG data were obtained at the same time that excellent fMRI brain images were achieved. Using this system we determined the relationship between the fMRI-measured brain activation and the handgrip force, and between the fMRI-measured brain activation and the EMG of finger flexor muscles. We found that in the whole brain and in the majority of motor function-related cortical fields, the degree of muscle activation is directly proportional to the amplitude of the brain signal determined by the fMRI measurement. The similarity in the relationship between muscle output and fMRI signal in a number of brain areas suggests that multiple cortical fields are involved in controlling muscle force. The factors that may contribute to the fMRI signals are discussed. A biophysical twitch force model was developed to predict force response under electrical stimulation. Comparison between experimental and modeled force

  16. Investigating short-range magnetism in strongly correlated materials via magnetic pair distribution function analysis and ab initio theory

    NASA Astrophysics Data System (ADS)

    Frandsen, Benjamin; Page, Katharine; Brunelli, Michela; Staunton, Julie; Billinge, Simon

    Short-range magnetic correlations are known to exist in a variety of strongly correlated electron systems, but our understanding of the role they play is challenged by the difficulty of experimentally probing such correlations. Magnetic pair distribution function (mPDF) analysis is a newly developed neutron total scattering method that can reveal short-range magnetic correlations directly in real space, and may therefore help ameliorate this difficulty. We present temperature-dependent mPDF measurements of the short-range magnetic correlations in the paramagnetic phase of antiferromagnetic MnO, an archetypal strongly correlated transition-metal oxide. We observe significant correlations on a ~1 nm length scale that differ substantially from the low-temperature long-range-ordered spin arrangement. With no free parameters, ab initio calculations using the self-interaction-corrected local spin density approximation of density functional theory quantitatively reproduce the magnetic correlations to a high degree of accuracy. These results yield valuable insight into the magnetic exchange in MnO and showcase the utility of the mPDF technique for studying magnetic properties of strongly correlated electron systems.

  17. Cardiovascular risks and brain function: a functional magnetic resonance imaging study of executive function in older adults.

    PubMed

    Chuang, Yi-Fang; Eldreth, Dana; Erickson, Kirk I; Varma, Vijay; Harris, Gregory; Fried, Linda P; Rebok, George W; Tanner, Elizabeth K; Carlson, Michelle C

    2014-06-01

    Cardiovascular (CV) risk factors, such as hypertension, diabetes, and hyperlipidemia are associated with cognitive impairment and risk of dementia in older adults. However, the mechanisms linking them are not clear. This study aims to investigate the association between aggregate CV risk, assessed by the Framingham general cardiovascular risk profile, and functional brain activation in a group of community-dwelling older adults. Sixty participants (mean age: 64.6 years) from the Brain Health Study, a nested study of the Baltimore Experience Corps Trial, underwent functional magnetic resonance imaging using the Flanker task. We found that participants with higher CV risk had greater task-related activation in the left inferior parietal region, and this increased activation was associated with poorer task performance. Our results provide insights into the neural systems underlying the relationship between CV risk and executive function. Increased activation of the inferior parietal region may offer a pathway through which CV risk increases risk for cognitive impairment.

  18. Nuclear magnetic resonance imaging and spectroscopy of human brain function.

    PubMed Central

    Shulman, R G; Blamire, A M; Rothman, D L; McCarthy, G

    1993-01-01

    The techniques of in vivo magnetic resonance (MR) imaging and spectroscopy have been established over the past two decades. Recent applications of these methods to study human brain function have become a rapidly growing area of research. The development of methods using standard MR contrast agents within the cerebral vasculature has allowed measurements of regional cerebral blood volume (rCBV), which are activity dependent. Subsequent investigations linked the MR relaxation properties of brain tissue to blood oxygenation levels which are also modulated by consumption and blood flow (rCBF). These methods have allowed mapping of brain activity in human visual and motor cortex as well as in areas of the frontal lobe involved in language. The methods have high enough spatial and temporal sensitivity to be used in individual subjects. MR spectroscopy of proton and carbon-13 nuclei has been used to measure rates of glucose transport and metabolism in the human brain. The steady-state measurements of brain glucose concentrations can be used to monitor the glycolytic flux, whereas subsequent glucose metabolism--i.e., the flux into the cerebral glutamate pool--can be used to measure tricarboxylic acid cycle flux. Under visual stimulation the concentration of lactate in the visual cortex has been shown to increase by MR spectroscopy. This increase is compatible with an increase of anaerobic glycolysis under these conditions as earlier proposed from positron emission tomography studies. It is shown how MR spectroscopy can extend this understanding of brain metabolism. Images Fig. 1 Fig. 2 Fig. 3 PMID:8475050

  19. What is feasible with imaging human brain function and connectivity using functional magnetic resonance imaging.

    PubMed

    Ugurbil, Kamil

    2016-10-01

    When we consider all of the methods we employ to detect brain function, from electrophysiology to optical techniques to functional magnetic resonance imaging (fMRI), we do not really have a 'golden technique' that meets all of the needs for studying the brain. We have methods, each of which has significant limitations but provide often complimentary information. Clearly, there are many questions that need to be answered about fMRI, which unlike other methods, allows us to study the human brain. However, there are also extraordinary accomplishments or demonstration of the feasibility of reaching new and previously unexpected scales of function in the human brain. This article reviews some of the work we have pursued, often with extensive collaborations with other co-workers, towards understanding the underlying mechanisms of the methodology, defining its limitations, and developing solutions to advance it. No doubt, our knowledge of human brain function has vastly expanded since the introduction of fMRI. However, methods and instrumentation in this dynamic field have evolved to a state that discoveries about the human brain based on fMRI principles, together with information garnered at a much finer spatial and temporal scale through other methods, are poised to significantly accelerate in the next decade.This article is part of the themed issue 'Interpreting BOLD: a dialogue between cognitive and cellular neuroscience'. PMID:27574313

  20. What is feasible with imaging human brain function and connectivity using functional magnetic resonance imaging.

    PubMed

    Ugurbil, Kamil

    2016-10-01

    When we consider all of the methods we employ to detect brain function, from electrophysiology to optical techniques to functional magnetic resonance imaging (fMRI), we do not really have a 'golden technique' that meets all of the needs for studying the brain. We have methods, each of which has significant limitations but provide often complimentary information. Clearly, there are many questions that need to be answered about fMRI, which unlike other methods, allows us to study the human brain. However, there are also extraordinary accomplishments or demonstration of the feasibility of reaching new and previously unexpected scales of function in the human brain. This article reviews some of the work we have pursued, often with extensive collaborations with other co-workers, towards understanding the underlying mechanisms of the methodology, defining its limitations, and developing solutions to advance it. No doubt, our knowledge of human brain function has vastly expanded since the introduction of fMRI. However, methods and instrumentation in this dynamic field have evolved to a state that discoveries about the human brain based on fMRI principles, together with information garnered at a much finer spatial and temporal scale through other methods, are poised to significantly accelerate in the next decade.This article is part of the themed issue 'Interpreting BOLD: a dialogue between cognitive and cellular neuroscience'.

  1. The effect of 3 T MRI on microleakage of amalgam restorations

    PubMed Central

    Yilmaz, S; Misirlioğlu, M

    2013-01-01

    Objectives: To evaluate the effects of 3 T magnetic field on microleakage of amalgam restorations containing three different types of silver (Ag). Methods: 60 extracted teeth were restored with three different types of amalgam filling materials. Restored teeth were sectioned mesiodistally and divided into experimental and control groups. Experimental groups were exposed to a magnetic field of 3 T for 20 min. All samples were plunged into 2% basic fuchsin solution and examined under a digital microscope by three different observers with regard to microleakage. Results: Statistical analysis showed significant differences in microleakage between the groups exposed to MRI and controls, whereas differences in microleakage between amalgam types were insignificant. Conclusions: The primary risk of MRI systems arises from the effects of its strong magnetic field on objects containing ferromagnetic materials. An MRI of 1.5 T is known to be safe for amalgam restorations. However, our research indicates that MRI is not completely devoid of any effects on amalgam restorations. PMID:23674614

  2. Magnetic nanoparticles: synthesis, functionalization, and applications in bioimaging and magnetic energy storage

    PubMed Central

    Frey, Natalie A.; Peng, Sheng; Cheng, Kai; Sun, Shouheng

    2009-01-01

    This tutorial review summarizes the recent advances in the chemical synthesis and potential applications of monodisperse magnetic nanoparticles. After a brief introduction to nanomagnetism, the review focuses on recent developments in solution phase syntheses of monodisperse MFe2O4, Co, Fe, CoFe, FePt and SmCo5 nanoparticles. The review further outlines the surface, structural, and magnetic properties of these nanoparticles for biomedicine and magnetic energy storage applications. PMID:19690734

  3. Biomedical Applications of Magnetically Functionalized Organic/Inorganic Hybrid Nanofibers

    PubMed Central

    Lee, Hwa-Jeong; Lee, Sang Joon; Uthaman, Saji; Thomas, Reju George; Hyun, Hoon; Jeong, Yong Yeon; Cho, Chong-Su; Park, In-Kyu

    2015-01-01

    Nanofibers are one-dimensional nanomaterial in fiber form with diameter less than 1 µm and an aspect ratio (length/diameter) larger than 100:1. Among the different types of nanoparticle-loaded nanofiber systems, nanofibers loaded with magnetic nanoparticles have gained much attention from biomedical scientists due to a synergistic effect obtained from the unique properties of both the nanofibers and magnetic nanoparticles. These magnetic nanoparticle-encapsulated or -embedded nanofiber systems can be used not only for imaging purposes but also for therapy. In this review, we focused on recent advances in nanofibers loaded with magnetic nanoparticles, their biomedical applications, and future trends in the application of these nanofibers. PMID:26084046

  4. Lectin-functionalized magnetic iron oxide nanoparticles for reproductive improvement

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Semen ejaculates contain heterogeneous sperm populations that can jeopardize male fertility. Recent development of nanotechnology in physiological systems may have applications in reproductive biology. Here, we used magnetic nanoparticles as a novel strategy for sperm purification to imp...

  5. Dual-function magnetic structure for toroidal plasma devices

    DOEpatents

    Brown, Robert L.

    1978-01-01

    This invention relates to a support system wherein the iron core and yoke of the plasma current system of a tokamak plasma containment device is redesigned to support the forces of the magnet coils. The containment rings, which occupy very valuable space around the magnet coils, are utilized to serve as yokes for the core such that the conventional yoke is eliminated. The overall result is an improved aspect ratio, reduction in structure, smaller overall size, and improved access to the plasma ring.

  6. Anti-Obesity Effects of Starter Fermented Kimchi on 3T3-L1 Adipocytes

    PubMed Central

    Lee, Kyung-Hee; Song, Jia-Le; Park, Eui-Seong; Ju, Jaehyun; Kim, Hee-Young; Park, Kun-Young

    2015-01-01

    The anti-obesity effects of starter (Leuconostoc mesenteroides+Lactobacillus plantarum) fermented kimchi on 3T3-L1 adipocyte were studied using naturally fermented kimchi (NK), a functional kimchi (FK, NK supplemented with green tea), and FK supplemented with added starters (FKS). Oil red O staining and cellular levels of triglyceride (TG) and glycerol were used to evaluate the in vitro anti-obesity effects of these kimchis in 3T3-L1 cells. The expressions of adipogenesis/lipogenesis-related genes of peroxisome proliferator-active receptor (PPAR)-γ, CCAAT/enhance-binding protein (C/EBP)-α, and fatty acid synthase (FAS) were determined by RT-PCR. Kimchis, especially FKS, markedly decreased TG levels and increased levels of intracellular glycerol and lipid lipolysis. In addition, FKS also reduced the mRNA levels of PPAR-γ, C/EBP-α, and FAS, which are related to adipogenesis/lipogenesis in 3T3-L1 cells. These results suggest the anti-obesity effects of FKS were to due to enhanced lipolysis and reduced adipogenesis/lipogenesis in 3T3-L1 adipocytes. PMID:26770918

  7. Fluorescence lifetime imaging of lipids during 3T3-L1 cell differentiation

    NASA Astrophysics Data System (ADS)

    Song, Young Sik; Won, Young Jae; Lee, Sang-Hak; Kim, Dug Young

    2014-03-01

    Obesity is becoming a big health problem in these days. Since increased body weight is due to increased number and size of the triglyceride-storing adipocytes, many researchers are working on differentiation conditions and processes of adipocytes. Adipocytes also work as regulators of whole-body energy homeostasis by secreting several proteins that regulate processes as diverse as haemostasis, blood pressure, immune function, angiogenesis and energy balance. 3T3-L1 cells are widely used cell line for studying adipogenesis because it can differentiate into an adipocyte-like phenotype under appropriate conditions. In this paper, we propose an effective fluorescence lifetime imaging technique which can easily distinguish lipids in membrane and those in lipid droplets. Nile red dyes are attached to lipids in 3T3-L1 cells. Fluorescence lifetime images were taken for 2 week during differentiation procedure of 3T3-L1 cells into adipocytes. We used 488 nm pulsed laser with 5MHz repetition rate and emission wavelength is 520 nm of Nile Red fluorescent dye. Results clearly show that the lifetime of Nile red in lipid droplets are smaller than those in cell membrane. Our results suggest that fluorescence lifetime imaging can be a very powerful tool to monitor lipid droplet formation in adipocytes from 3T3-L1 cells.

  8. Multi-tensor tractography of the motor pathway at 3T: a volunteer study.

    PubMed

    Akter, Masuma; Hirai, Toshinori; Sasao, Akira; Nishimura, Shinichiro; Uetani, Hiroyuki; Iwashita, Koya; Yamashita, Yasuyuki

    2011-01-01

    Conventional single-tensor tractography cannot depict the entire motor tract of the corticospinal tract because of fiber-crossing and other factors. Using a 3-tesla magnetic resonance (MR) unit, we compared single- and multi-tensor methods for the tract ratio of the 5 major components of the motor pathway, the lower extremity, trunk, hand, face, and tongue, in 5 healthy volunteers. Multi-tensor tractography is better than single-tensor tractography at 3T in depicting more fibers of non-trunk areas from the primary motor cortex.

  9. Electron distribution function and recombination coefficient in ultracold plasma in a magnetic field

    SciTech Connect

    Bobrov, A. A.; Bronin, S. Ya.; Zelener, B. B.; Zelener, B. V.; Manykin, E. A.; Khikhlukha, D. R.

    2013-07-15

    The electron distribution function and diffusion coefficient in energy space have been calculated for the first time for a weakly coupled ultracold plasma in a magnetic field in the range of magnetic fields B = 100-50000 G for various temperatures. The dependence of these characteristics on the magnetic field is analyzed and the distribution function is shown to depend on the electron energy shift in a magnetic field. The position of the 'bottleneck' of the distribution function has been found to be shifted toward negative energies with increasing magnetic field. The electron velocity autocorrelators as a function of the magnetic field have been calculated; their behavior suggests that the frequency of collisions between charged particles decreases significantly with increasing magnetic field. The collisional recombination coefficient {alpha}{sub B} has been calculated in the diffusion approximation for a weakly coupled ultracold plasma in a magnetic field. An increase in magnetic field is shown to lead to a decrease in {alpha}{sub B} and this decrease can be several orders of magnitude.

  10. Non-perturbative calculation of molecular magnetic properties within current-density functional theory

    SciTech Connect

    Tellgren, E. I. Lange, K. K.; Ekström, U.; Helgaker, T.; Teale, A. M.; Furness, J. W.

    2014-01-21

    We present a novel implementation of Kohn–Sham density-functional theory utilizing London atomic orbitals as basis functions. External magnetic fields are treated non-perturbatively, which enable the study of both magnetic response properties and the effects of strong fields, using either standard density functionals or current-density functionals—the implementation is the first fully self-consistent implementation of the latter for molecules. Pilot applications are presented for the finite-field calculation of molecular magnetizabilities, hypermagnetizabilities, and nuclear magnetic resonance shielding constants, focusing on the impact of current-density functionals on the accuracy of the results. Existing current-density functionals based on the gauge-invariant vorticity are tested and found to be sensitive to numerical details of their implementation. Furthermore, when appropriately regularized, the resulting magnetic properties show no improvement over standard density-functional results. An advantage of the present implementation is the ability to apply density-functional theory to molecules in very strong magnetic fields, where the perturbative approach breaks down. Comparison with high accuracy full-configuration-interaction results show that the inadequacies of current-density approximations are exacerbated with increasing magnetic field strength. Standard density-functionals remain well behaved but fail to deliver high accuracy. The need for improved current-dependent density-functionals, and how they may be tested using the presented implementation, is discussed in light of our findings.

  11. Density-functional study of two Fe4-based single-molecule magnets

    NASA Astrophysics Data System (ADS)

    Ribas-Arino, Jordi; Baruah, Tunna; Pederson, Mark R.

    2005-07-01

    We present the results of our all-electron density-functional calculations on the electronic structure and magnetic anisotropy energy of the [Fe4(OMe)6(dpm)6] and [Fe4(thme)2(dpm)6] molecular clusters, which are experimentally found to behave as single-molecule magnets. The calculated magnetic anisotropy energy barriers are 2.65 and 15.8K, respectively, which agree with the experimental data. We also present a density-functional study on the effect of the structure distortions on the magnetic anisotropy of the [Fe(H2O)6]3+ complex. This study, together with an analysis of the projected anisotropies of each iron ion in both molecular clusters, allows us to qualitatively understand why the magnetic anisotropy energy (MAE) barrier of the second single-molecule magnet (SMM) is larger than the MAE of the first SMM.

  12. Chiral dynamics in a magnetic field from the functional renormalization group

    NASA Astrophysics Data System (ADS)

    Kamikado, Kazuhiko; Kanazawa, Takuya

    2014-03-01

    We investigate the quark-meson model in a magnetic field using the functional renormalization group equation beyond the local-potential approximation. Our truncation of the effective action involves anisotropic wave function renormalization for mesons, which allows us to investigate how the magnetic field distorts the propagation of neutral mesons. Solving the flow equation numerically, we find that the transverse velocity of mesons decreases with the magnetic field at all temperatures, which is most prominent at zero temperature. The meson screening masses and the pion decay constants are also computed. The constituent quark mass is found to increase with magnetic field at all temperatures, resulting in the crossover temperature that increases monotonically with the magnetic field. This tendency is consistent with most model calculations but not with the lattice simulation performed at the physical point. Our work suggests that the strong anisotropy of meson propagation may not be the fundamental origin of the inverse magnetic catalysis.

  13. Expression of Nanog gene promotes NIH3T3 cell proliferation

    SciTech Connect

    Zhang Jingyu; Wang Xia; Chen Bing; Suo Guangli; Zhao Yanhong; Duan Ziyuan; Dai Jianwu . E-mail: jwdai@genetics.ac.cn

    2005-12-16

    Cells are the functional elements in tissue engineering and regenerative medicine. A large number of cells are usually needed for these purposes. However, there are numbers of limitations for in vitro cell proliferation. Nanog is an important self-renewal determinant in embryonic stem cells. However, it remains unknown whether Nanog will influence the cell cycle and cell proliferation of mature cells. In this study, we expressed Nanog in NIH3T3 cells and showed that expression of Nanog in NIH3T3 promoted cells to enter into S phase and enhanced cell proliferation. This suggests that Nanog gene might function in a similar fashion in mature cells as in ES cells. In addition, it may provide an approach for in vitro cell expansion.

  14. Human papillomavirus type 16 DNA-induced malignant transformation of NIH 3T3 cells

    SciTech Connect

    Yasumoto, S.; Burkhardt, A.L.; Doniger, J.; DiPaolo, J.A.

    1986-02-01

    A biological function for human papillomavirus 16 (HPV 16) DNA was demonstrated by transformation of NIH 3T3 cells. HPV 16 DNA has been found frequently in genital cancer and has been classified as a papillomavirus on the basis of DNA homology. A recombinant HPV 16 DNA (pSHPV16d), which contains a head-to-tail dimer of the full-length HPV 16 genome, induced morphologic transformation; the transformed cells were tumorigenic in nude mice. Expression of transforming activity was unique because of the long latency period (more than 4 weeks) required for induction of morphologic transformation and because the transfected DNA existed primarily in a multimeric form with some rearrangement. Furthermore, virus-specific RNAs were expressed in the transformants. The transformation of NIH 3T3 cells provides a model for analyzing the functions of HPV 16, which is associated with cervical carcinomas.

  15. Functionalization and magnetization of carbon nanotubes using Co-60 gamma-ray irradiation

    NASA Astrophysics Data System (ADS)

    Chen, C. Y.; Fu, M. J.; Tsai, C. Y.; Lin, F. H.; Chen, K. Y.

    2014-10-01

    Functionalized magnetic carbon nanotubes (CNTs) can be used in the biological and biomedical fields as biosensors, drug delivery systems, etc., which makes research into processes for manufacturing modified CNTs quite important. In this paper, Co-60 gamma irradiation is shown to be an effective tool for fabricating functionalized and magnetized CNTs. After the Co-60 gamma irradiation, the presence of carboxylic functional groups on the CNT walls was confirmed by their Fourier transform infrared spectra, and the presence of Fe3O4 was verified by the X-ray diffraction patterns. The functionalized and magnetized CNTs produced using Co-60 gamma irradiation have excellent dispersion properties. The techniques for functionalizing and magnetizing CNTs are introduced in this paper, and applications of the modified CNTs will be reported after more data are gathered.

  16. Force-free magnetic fields - Generating functions and footpoint displacements

    NASA Technical Reports Server (NTRS)

    Wolfson, Richard; Verma, Ritu

    1991-01-01

    This paper presents analytic and numerical calculations that explore equilibrium sequences of bipolar force-free magnetic fields in relation to displacments of their magnetic footpoints. It is shown that the appearance of magnetic islands - sometimes interpreted as marking the loss of equilibrium in models of the solar atmosphere - is likely associated only with physically unrealistic footpoint displacements such as infinite separation or 'tearing' of the model photosphere. The work suggests that the loss of equilibrium in bipolar configurations, sometimes proposed as a mechanism for eruptive solar events, probably requires either fully three-dimensional field configurations or nonzero plasma pressure. The results apply only to fields that are strictly bipolar, and do not rule out equilibrium loss in more complex structures such as quadrupolar fields.

  17. CLOCK promotes 3T3-L1 cell proliferation via Wnt signaling.

    PubMed

    Zhu, Zhu; Hua, Bingxuan; Xu, Lirong; Yuan, Gongsheng; Li, Ermin; Li, Xiaobo; Sun, Ning; Yan, Zuoqin; Lu, Chao; Qian, Ruizhe

    2016-07-01

    Circadian genes control most of the physiological functions including cell cycle. Cell proliferation is a critical factor in the differentiation of progenitor cells. However, the role of Clock gene in the regulation of cell cycle via wingless-type (Wnt) pathway and the relationship between Clock and adipogenesis are unclear. We found that the circadian locomotor output cycles kaput (Clock) regulated the proliferation and the adipogenesis of 3T3-L1 preadipocytes. We found that Clock attenuation inhibited the viability of 3T3-L1 preadipocytes in the cell counting kit 8. The expression of c-Myc and Cyclin D1 decreased dramatically in 3T3-L1 when Clock was silenced with short interfering RNA and was also decreased in fat tissue and adipose tissue-derived stem cells of Clock(Δ19) mice. Clock directly controls the expression of the components of Wnt signal transduction pathway, which was verified by serum shock, chromatin immunoprecipitation, Western blot, and quantitative real-time polymerase chain reaction (qRT-PCR). Furthermore, IWR-1, a Wnt signal pathway inhibitor, inhibited the cell cycle promotion by CLOCK, which was detected by cell viability assay, flow cytometry, and qRT-PCR. Therefore, CLOCK transcription control of Wnt signaling promotes cell cycle progression in 3T3-L1 preadipocytes. Clock inhibited the adipogenesis on day 2 in 3T3-L1 cells via Oil Red O staining and qRT-PCR detection and probably related to cellular differentiation. These data provide evidence that the circadian gene Clock regulates the proliferation of preadipocytes and affects adipogenesis. © 2016 IUBMB Life, 68(7):557-568, 2016. PMID:27194636

  18. Vaspin promotes 3T3-L1 preadipocyte differentiation

    PubMed Central

    Liu, Ping; Wu, Jine; Zhou, Xin; Wang, Liping; Han, Wenqi; Lv, Ying; Sun, Chaofeng

    2015-01-01

    Vaspin, a novel adipocyte factor secreted from visceral adipose tissues, is associated with obesity and insulin resistance and can regulate glucose and lipid metabolism, increase insulin sensitivity, and suppress inflammation; however, the underlying mechanisms remain unknown. Proliferation and maladaptive differentiation are important pathological mechanisms underlying obesity. This study aimed to evaluate the effects of vaspin on the proliferation and differentiation of preadipocyte 3T3-L1 cells and to explore the likely mechanisms responsible for 3T3-L1 differentiation. Vaspin was added to cultured 3T3-L1 cells, and the differentiation of adipocytes was evaluated using Oil Red O staining. The AKT signaling pathway and specific differentiation factors related to the differentiation of preadipocyte 3T3-L1 cells, peroxisome proliferator-activated γ and the CCAAT/enhancer-binding protein (C/EBP) family, were evaluated using reverse transcription polymerase chain reaction (RT-PCR) and western blot analyses during the early phase of differentiation. Additionally, adiponectin mRNA, interleukin-6 mRNA (IL-6 mRNA), and glucose transporter-4 (GLUT4) protein levels were measured in the differentiated adipocytes. The results indicated that vaspin promotes the intracellular accumulation of lipids and increases differentiation-related factors, including peroxisome proliferator-activated receptor γ, C/EBPα, and free fatty acid-binding protein 4 (FABP4), in a dose-dependent manner. Additionally, vaspin (200 ng/mL) increased the mRNA and protein levels of C/EBPβ, peroxisome proliferator-activated γ, C/EBPα, and FABP4. Moreover, compared with the control, significantly smaller eight-day differentiated adipocytes were observed, and these cells exhibited decreased IL-6 mRNA and increased GLUT4 mRNA levels; these results also indicated the potential of vaspin to promote the insulin-mediated AKT signaling pathway during the early phase of differentiation. In conclusion

  19. Magnetically triggered dual functional nanoparticles for resistance-free apoptotic hyperthermia.

    PubMed

    Yoo, Dongwon; Jeong, Heeyeong; Noh, Seung-Hyun; Lee, Jae-Hyun; Cheon, Jinwoo

    2013-12-01

    Overcoming resistance: Heat-treated cancer cells possess a protective mechanism for resistance and survival. Resistance-free apoptosis-inducing magnetic nanoparticles (RAINs) successfully promote hyperthermic apoptosis, obstructing cell survival by triggering two functional units of heat generation and the release of geldanamycin (GM) for heat shock protein (Hsp) inhibition under an alternating magnetic field (AMF). PMID:24281889

  20. Magnetically triggered dual functional nanoparticles for resistance-free apoptotic hyperthermia.

    PubMed

    Yoo, Dongwon; Jeong, Heeyeong; Noh, Seung-Hyun; Lee, Jae-Hyun; Cheon, Jinwoo

    2013-12-01

    Overcoming resistance: Heat-treated cancer cells possess a protective mechanism for resistance and survival. Resistance-free apoptosis-inducing magnetic nanoparticles (RAINs) successfully promote hyperthermic apoptosis, obstructing cell survival by triggering two functional units of heat generation and the release of geldanamycin (GM) for heat shock protein (Hsp) inhibition under an alternating magnetic field (AMF).

  1. Superconducting toroidal combined-function magnet for a compact ion beam cancer therapy gantry

    NASA Astrophysics Data System (ADS)

    Robin, D. S.; Arbelaez, D.; Caspi, S.; Sun, C.; Sessler, A.; Wan, W.; Yoon, M.

    2011-12-01

    A superconducting, combined-function, 5 T, 90°, toroidal magnet with a large bore is described in this paper. This magnet is designed to be the last and most difficult part of a compact superconducting magnet-based carbon gantry optics for ion beam cancer therapy. The relatively small size of this toroidal magnet allows for a gantry the size of which is smaller or at least comparable to that of a proton gantry. The gantry design places the toroidal magnet between the scanning magnets and the patient, that is the scanning magnets are placed midway through the gantry. By optimizing the coil winding configuration of this magnet, near point-to-parallel optics is achieved between the scanning magnets and the patient; while at the same time there is only a small distortion of the beam-shape when scanning. We show that the origin of the beam-shape distortion is the strong sextupole components, whose effects are greatly pronounced when the beam is widely steered in the magnet. A method to correct such an undesirable effect is suggested and demonstrated by a numerical particle tracking through the calculated three-dimensional magnetic field.

  2. Magnetic and antimagnetic rotation in covariant density functional theory

    SciTech Connect

    Zhao, P. W.; Liang, H. Z.; Peng, J.; Ring, P.; Zhang, S. Q.; Meng, J.

    2012-10-20

    Progress on microscopic and self-consistent description of the magnetic rotation and antimagnetic rotation phenomena in tilted axis cranking relativistic mean-field theory based on a point-coupling interaction are briefly reviewed. In particular, the microscopic pictures of the shears mechanism in {sup 60}Ni and the two shears-like mechanism in {sup 105}Cd are discussed.

  3. Functional magnetic resonance imaging reflects changes in brain functioning with sedation.

    PubMed

    Starbuck, Victoria N; Kay, Gary G; Platenberg, R. Craig; Lin, Chin-Shoou; Zielinski, Brandon A

    2000-12-01

    Functional magnetic resonance imaging (fMRI) studies have demonstrated localized brain activation during cognitive tasks. Brain activation increases with task complexity and decreases with familiarity. This study investigates how sleepiness alters the relationship between brain activation and task familiarity. We hypothesize that sleepiness prevents the reduction in activation associated with practice. Twenty-nine individuals rated their sleepiness using the Stanford Sleepiness Scale before fMRI. During imaging, subjects performed the Paced Auditory Serial Addition Test, a continuous mental arithmetic task. A positive correlation was observed between self-rated sleepiness and frontal brain activation. Fourteen subjects participated in phase 2. Sleepiness was induced by evening dosing with chlorpheniramine (CP) (8 mg or 12 mg) and terfenadine (60 mg) in the morning for 3 days before the second fMRI scan. The Multiple Sleep Latency Test (MSLT) was also performed. Results revealed a significant increase in fMRI activation in proportion to the dose of CP. In contrast, for all subjects receiving placebo there was a reduction in brain activation. MSLT revealed significant daytime sleepiness for subjects receiving CP. These findings suggest that sleepiness interferes with efficiency of brain functioning. The sleepy or sedated brain shows increased oxygen utilization during performance of a familiar cognitive task. Thus, the beneficial effect of prior task exposure is lost under conditions of sedation. Copyright 2000 John Wiley & Sons, Ltd. PMID:12404614

  4. True Pathologic Abnormality versus Artifact Foot Position and Magic Angle Artifact in the Peroneal Tendons with 3T Imaging.

    PubMed

    Horn, Deena B; Meyers, Steven; Astor, William

    2015-09-01

    Magnetic resonance imaging is a commonly ordered examination by many foot and ankle surgeons for ankle pain and suspected peroneal tendon pathologic abnormalities. Magic angle artifact is one of the complexities associated with this imaging modality. Magic angle refers to the increased signal on magnetic resonance images associated with the highly organized collagen fibers in tendons and ligaments when they are orientated at a 55° angle to the main magnetic field. We present several examples from a clinical practice setting using 3T imaging illustrating a substantial reduction in magic angle artifact of the peroneal tendon in the prone plantarflexed position compared with the standard neutral (right angle) position.

  5. Brain functional magnetic resonance imaging response to glucose and fructose infusions in humans

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: In animals, intracerebroventricular glucose and fructose have opposing effects on appetite and weight regulation. In humans, functional brain magnetic resonance imaging (fMRI) studies during carbohydrate ingestion suggest that glucose may regulate HT signaling but are potentially confoun...

  6. Quantitative planar and volumetric cardiac measurements using 64 MDCT and 3T MRI versus standard 2D and M-mode echocardiography: Does anesthetic protocol matter?

    PubMed Central

    Drees, Randi; Johnson, Rebecca A; Stepien, Rebecca L; Rio, Alejandro Munoz Del; Saunders, Jimmy H; François, Christopher J

    2016-01-01

    Cross-sectional imaging of the heart utilizing computed tomography (CT) and magnetic resonance imaging (MRI) has been shown to be superior for the evaluation of cardiac morphology and systolic function in humans compared to echocardiography. The purpose of this prospective study was to test the effects of two different anesthetic protocols on cardiac measurements in 10 healthy beagle dogs using 64-multidetector row computed tomographic angiography (64-MDCTA), 3T magnetic resonance (MRI) and standard awake echocardiography. Both anesthetic protocols used propofol for induction and isoflourane for anesthetic maintenance. In addition, protocol A used midazolam/fentanyl and protocol B used dexmedetomedine as premedication and constant rate infusion during the procedure. Significant elevations in systolic and mean blood pressure were present when using protocol B. There was overall good agreement between the variables of cardiac size and systolic function generated from the MDCTA and MRI exams and no significant difference was found when comparing the variables acquired using either anesthetic protocol within each modality. Systolic function variables generated using 64-MDCTA and 3T MRI were only able to predict the left ventricular end diastolic volume as measured during awake echocardiogram when using protocol B and 64-MDCTA. For all other systolic function variables, prediction of awake echocardiographic results was not possible (P = 1). Planar variables acquired using MDCTA or MRI did not allow prediction of the corresponding measurements generated using echocardiography in the awake patients (P=1). Future studies are needed to validate this approach in a more varied population and clinically affected dogs. PMID:26082285

  7. QUANTITATIVE PLANAR AND VOLUMETRIC CARDIAC MEASUREMENTS USING 64 MDCT AND 3T MRI VS. STANDARD 2D AND M-MODE ECHOCARDIOGRAPHY: DOES ANESTHETIC PROTOCOL MATTER?

    PubMed

    Drees, Randi; Johnson, Rebecca A; Stepien, Rebecca L; Munoz Del Rio, Alejandro; Saunders, Jimmy H; François, Christopher J

    2015-01-01

    Cross-sectional imaging of the heart utilizing computed tomography and magnetic resonance imaging (MRI) has been shown to be superior for the evaluation of cardiac morphology and systolic function in humans compared to echocardiography. The purpose of this prospective study was to test the effects of two different anesthetic protocols on cardiac measurements in 10 healthy beagle dogs using 64-multidetector row computed tomographic angiography (64-MDCTA), 3T magnetic resonance (MRI) and standard awake echocardiography. Both anesthetic protocols used propofol for induction and isoflourane for anesthetic maintenance. In addition, protocol A used midazolam/fentanyl and protocol B used dexmedetomedine as premedication and constant rate infusion during the procedure. Significant elevations in systolic and mean blood pressure were present when using protocol B. There was overall good agreement between the variables of cardiac size and systolic function generated from the MDCTA and MRI exams and no significant difference was found when comparing the variables acquired using either anesthetic protocol within each modality. Systolic function variables generated using 64-MDCTA and 3T MRI were only able to predict the left ventricular end diastolic volume as measured during awake echocardiogram when using protocol B and 64-MDCTA. For all other systolic function variables, prediction of awake echocardiographic results was not possible (P = 1). Planar variables acquired using MDCTA or MRI did not allow prediction of the corresponding measurements generated using echocardiography in the awake patients (P = 1). Future studies are needed to validate this approach in a more varied population and clinically affected dogs. PMID:26082285

  8. Small-angle neutron scattering correlation functions of bulk magnetic materials

    PubMed Central

    Mettus, Denis; Michels, Andreas

    2015-01-01

    On the basis of the continuum theory of micromagnetics, the correlation function of the spin-misalignment small-angle neutron scattering cross section of bulk ferromagnets (e.g. elemental polycrystalline ferromagnets, soft and hard magnetic nanocomposites, nanoporous ferromagnets, or magnetic steels) is computed. For such materials, the spin disorder which is related to spatial variations in the saturation magnetization and magnetic anisotropy field results in strong spin-misalignment scattering dΣM/dΩ along the forward direction. When the applied magnetic field is perpendicular to the incoming neutron beam, the characteristics of dΣM/dΩ (e.g. the angular anisotropy on a two-dimensional detector or the asymptotic power-law exponent) are determined by the ratio of magnetic anisotropy field strength H p to the jump ΔM in the saturation magnetization at internal interfaces. Here, the corresponding one- and two-dimensional real-space correlations are analyzed as a function of applied magnetic field, the ratio H p/ΔM, the single-particle form factor and the particle volume fraction. Finally, the theoretical results for the correlation function are compared with experimental data on nanocrystalline cobalt and nickel. PMID:26500464

  9. Interaction of gustatory and lingual somatosensory perceptions at the cortical level in the human: a functional magnetic resonance imaging study.

    PubMed

    Cerf-Ducastel, B; Van de Moortele, P F; MacLeod, P; Le Bihan, D; Faurion, A

    2001-05-01

    The present study has investigated interaction at the cortical level in the human between two major components of flavor perception, pure chemical gustatory and lingual somatosensory perception. Twelve subjects participated in a functional magnetic resonance imaging study and tasted six stimuli, applied on the whole tongue, among which four were pure gustatory stimuli (NaCl, aspartame, quinine and HCl, pH 2.4 or 2.2) and two were both taste and lingual somatosensory stimuli, i.e. somato-gustatory stimuli (HCl, pH 1.6 or 1.5, and aluminum potassium sulfate). Functional images were acquired with an echo planar sequence on a 3 T system and were individually processed by correlation with the temporal perception profile. Both sets of stimuli showed activation in the same cortical areas, namely the insula, the rolandic operculum (base of the pre- and post-central gyri), the frontal operculum and the temporal operculum, confirming a wide overlap of taste and lingual somatosensory representations. However, the relative activation across areas and the analysis of co-activated areas across all runs for each set of stimuli allowed discrimination of taste and somatosensory modalities. Factor analysis of correspondences indicated different patterns of activation across the sub-insular and opercular regions, depending on the gustatory or somato-gustatory nature of the stimuli. For gustatory stimuli different activation patterns for the superior and inferior parts of the insula suggested a difference in function between these two insular sub-regions. Furthermore, the left inferior insula was co-activated with the left angular gyrus, a structure involved in semantic processing. In contrast, only somato-gustatory stimuli specifically produced a simultaneous and symmetrical activation of both the left and right rolandic opercula, which include a part of the sensory homunculus dedicated to the tactile representation of oral structures.

  10. General protocol for the synthesis of functionalized magnetic nanoparticles for magnetic resonance imaging from protected metal-organic precursors.

    PubMed

    Hu, He; Zhang, Chongkun; An, Lu; Yu, Yanrong; Yang, Hong; Sun, Jin; Wu, Huixia; Yang, Shiping

    2014-06-01

    The development of magnetic nanoparticles (MNPs) with functional groups has been intensively pursued in recent years. Herein, a simple, versatile, and cost-effective strategy to synthesize water-soluble and amino-functionalized MNPs, based on the thermal decomposition of phthalimide-protected metal-organic precursors followed by deprotection, was developed. The resulting amino-functionalized Fe3O4, MnFe2O4, and Mn3O4 MNPs with particle sizes of about 14.3, 7.5, and 6.6 nm, respectively, had narrow size distributions and good dispersibility in water. These MNPs also exhibited high magnetism and relaxivities of r2 = 107.25 mM(-1)  s(-1) for Fe3O4, r2 = 245.75 mM(-1)  s(-1) for MnFe2O4, and r1 = 2.74 mM(-1)  s(-1) for Mn3O4. The amino-functionalized MNPs were further conjugated with a fluorescent dye (rhodamine B) and a targeting ligand (folic acid: FA) and used as multifunctional probes. Magnetic resonance imaging and flow-cytometric studies showed that these probes could specifically target cancer cells overexpressing FA receptors. This new protocol opens a new way for the synthesis and design of water-soluble and amino-functionalized MNPs by an easy and versatile route.

  11. General protocol for the synthesis of functionalized magnetic nanoparticles for magnetic resonance imaging from protected metal-organic precursors.

    PubMed

    Hu, He; Zhang, Chongkun; An, Lu; Yu, Yanrong; Yang, Hong; Sun, Jin; Wu, Huixia; Yang, Shiping

    2014-06-01

    The development of magnetic nanoparticles (MNPs) with functional groups has been intensively pursued in recent years. Herein, a simple, versatile, and cost-effective strategy to synthesize water-soluble and amino-functionalized MNPs, based on the thermal decomposition of phthalimide-protected metal-organic precursors followed by deprotection, was developed. The resulting amino-functionalized Fe3O4, MnFe2O4, and Mn3O4 MNPs with particle sizes of about 14.3, 7.5, and 6.6 nm, respectively, had narrow size distributions and good dispersibility in water. These MNPs also exhibited high magnetism and relaxivities of r2 = 107.25 mM(-1)  s(-1) for Fe3O4, r2 = 245.75 mM(-1)  s(-1) for MnFe2O4, and r1 = 2.74 mM(-1)  s(-1) for Mn3O4. The amino-functionalized MNPs were further conjugated with a fluorescent dye (rhodamine B) and a targeting ligand (folic acid: FA) and used as multifunctional probes. Magnetic resonance imaging and flow-cytometric studies showed that these probes could specifically target cancer cells overexpressing FA receptors. This new protocol opens a new way for the synthesis and design of water-soluble and amino-functionalized MNPs by an easy and versatile route. PMID:24771671

  12. Exogenous MC3T3 preosteoblasts migrate systemically and mitigate the adverse effects of wear particles.

    PubMed

    Fritton, Kate; Ren, Pei-Gen; Gibon, Emmanuel; Rao, Allison J; Ma, Ting; Biswal, Sandip; Gambhir, Sanjiv S; Goodman, Stuart B

    2012-12-01

    Understanding how relevant cell types respond to wear particles will reveal new avenues for treating osteolysis following joint replacements. In this study, we investigate the effects of ultrahigh molecular weight polyethylene (UHMWPE) particles on preosteoblast migration and function. We infused UHMWPE particles or saline into the left femur of mice and injected luciferase-expressing preosteoblasts (MC3T3 cells) into each left ventricle. Bioluminescence imaging (BLI) confirmed systemic administration of MC3T3 cells. BLI throughout the 28-day experiment showed greater MC3T3 migration to the site of particle infusion than to the site of saline infusion, with significant differences on days 0, 4, and 6 (p≤0.055). Immunostaining revealed a greater number of osteoblasts and osteoclasts in the particle-infused femora, indicating greater bone turnover. The bone mineralization of the particle-infused femora increased significantly when compared to saline-infused femora (an increase of 146.4±27.9 vs. 12.8±8.7 mg/mL, p=0.008). These results show that infused preosteoblasts can migrate to the site of wear particles. Additionally, as the migrated cells were associated with increased bone mineralization in spite of the presence of particles, increasing osteoblast recruitment is a potential strategy for combating bone loss due to increased osteoclast/macrophage number and decreased osteoblast function.

  13. Exogenous MC3T3 Preosteoblasts Migrate Systemically and Mitigate the Adverse Effects of Wear Particles

    PubMed Central

    Fritton, Kate; Ren, Pei-Gen; Gibon, Emmanuel; Rao, Allison J.; Ma, Ting; Biswal, Sandip; Gambhir, Sanjiv S.

    2012-01-01

    Understanding how relevant cell types respond to wear particles will reveal new avenues for treating osteolysis following joint replacements. In this study, we investigate the effects of ultrahigh molecular weight polyethylene (UHMWPE) particles on preosteoblast migration and function. We infused UHMWPE particles or saline into the left femur of mice and injected luciferase-expressing preosteoblasts (MC3T3 cells) into each left ventricle. Bioluminescence imaging (BLI) confirmed systemic administration of MC3T3 cells. BLI throughout the 28-day experiment showed greater MC3T3 migration to the site of particle infusion than to the site of saline infusion, with significant differences on days 0, 4, and 6 (p≤0.055). Immunostaining revealed a greater number of osteoblasts and osteoclasts in the particle-infused femora, indicating greater bone turnover. The bone mineralization of the particle-infused femora increased significantly when compared to saline-infused femora (an increase of 146.4±27.9 vs. 12.8±8.7 mg/mL, p=0.008). These results show that infused preosteoblasts can migrate to the site of wear particles. Additionally, as the migrated cells were associated with increased bone mineralization in spite of the presence of particles, increasing osteoblast recruitment is a potential strategy for combating bone loss due to increased osteoclast/macrophage number and decreased osteoblast function. PMID:22741555

  14. Topiramate effects lipolysis in 3T3-L1 adipocytes

    PubMed Central

    MARTINS, GABRIELA POLTRONIERI CAMPAGNARO; SOUZA, CAMILA OLIVEIRA; MARQUES, SCHEROLIN; LUCIANO, THAIS FERNANDES; DA SILVA PIERI, BRUNO LUIZ; ROSA, JOSÉ CÉSAR; DA SILVA, ADELINO SANCHEZ RAMOS; PAULI, JOSÉ RODRIGO; CINTRA, DENNYS ESPER; ROPELLE, EDUARDO ROCHETE; RODRIGUES, BRUNO; DE LIRA, FABIO SANTOS; DE SOUZA, CLAUDIO TEODORO

    2015-01-01

    Studies have shown that topiramate (TPM)-induced weight loss can be dependent on the central nervous system (CNS). However, the direct action of TPM on adipose tissue has not been tested previously. Thus, the present study aimed to examine whether TPM modulates lipolysis in 3T3-L1. The 3T3-L1 cells were incubated in 50 µM TPM for 30 min. The β-adrenergic stimulator, isoproterenol, was used as a positive control. The release of lactate dehydrogenase, non-esterified fatty acid, glycerol and incorporation of 14C-palmitate to lipid were analyzed. The phosphorylation of protein kinase A (PKA), hormone-sensitive lipase (HSL), adipocyte triglyceride lipase (ATGL) and perilipin A, as well as the protein levels of comparative genetic identification 58 (CGI-58) were assessed. The levels of glycerol and non-esterified fatty acid increased markedly when the cells were treated with TPM. The TPM effects were similar to the isoproterenol positive control. Additionally, TPM reduced lipogenesis. These results were observed without any change in cell viability. Finally, the phosphorylation of PKA, HSL, ATGL and perilipin A, as well as the protein levels of CGI-58 were increased compared to the control cells. These results were similar to those observed in the cells treated with isoproterenol. The present results show that TPM increased the phosphorylation of pivotal lipolytic enzymes, which induced lipolysis in 3T3-L1 adipocytes, suggesting that this drug may act directly in the adipose tissue independent from its effect on the CNS. PMID:26623024

  15. Phonon and magnetic structure in δ-plutonium from density-functional theory

    NASA Astrophysics Data System (ADS)

    Söderlind, Per; Zhou, F.; Landa, A.; Klepeis, J. E.

    2015-10-01

    We present phonon properties of plutonium metal obtained from a combination of density-functional-theory (DFT) electronic structure and the recently developed compressive sensing lattice dynamics (CSLD). The CSLD model is here trained on DFT total energies of several hundreds of quasi-random atomic configurations for best possible accuracy of the phonon properties. The calculated phonon dispersions compare better with experiment than earlier results obtained from dynamical mean-field theory. The density-functional model of the electronic structure consists of disordered magnetic moments with all relativistic effects and explicit orbital-orbital correlations. The magnetic disorder is approximated in two ways: (i) a special quasi-random structure and (ii) the disordered-local-moment method within the coherent potential approximation. Magnetism in plutonium has been debated intensely, but the present magnetic approach for plutonium is validated by the close agreement between the predicted magnetic form factor and that of recent neutron-scattering experiments.

  16. Phonon and magnetic structure in δ-plutonium from density-functional theory

    SciTech Connect

    Söderlind, Per; Zhou, F.; Landa, A.; Klepeis, J. E.

    2015-10-30

    We present phonon properties of plutonium metal obtained from a combination of density-functional-theory (DFT) electronic structure and the recently developed compressive sensing lattice dynamics (CSLD). The CSLD model is here trained on DFT total energies of several hundreds of quasi-random atomic configurations for best possible accuracy of the phonon properties. The calculated phonon dispersions compare better with experiment than earlier results obtained from dynamical mean-field theory. The density-functional model of the electronic structure consists of disordered magnetic moments with all relativistic effects and explicit orbital-orbital correlations. The magnetic disorder is approximated in two ways: (i) a special quasi-random structure and (ii) the disordered-local-moment (DLM) method within the coherent potential approximation. Magnetism in plutonium has been debated intensely, However, the present magnetic approach for plutonium is validated by the close agreement between the predicted magnetic form factor and that of recent neutron-scattering experiments.

  17. Magnetic assembly of transparent and conducting graphene-based functional composites

    NASA Astrophysics Data System (ADS)

    Le Ferrand, Hortense; Bolisetty, Sreenath; Demirörs, Ahmet F.; Libanori, Rafael; Studart, André R.; Mezzenga, Raffaele

    2016-06-01

    Innovative methods producing transparent and flexible electrodes are highly sought in modern optoelectronic applications to replace metal oxides, but available solutions suffer from drawbacks such as brittleness, unaffordability and inadequate processability. Here we propose a general, simple strategy to produce hierarchical composites of functionalized graphene in polymeric matrices, exhibiting transparency and electron conductivity. These are obtained through protein-assisted functionalization of graphene with magnetic nanoparticles, followed by magnetic-directed assembly of the graphene within polymeric matrices undergoing sol-gel transitions. By applying rotating magnetic fields or magnetic moulds, both graphene orientation and distribution can be controlled within the composite. Importantly, by using magnetic virtual moulds of predefined meshes, graphene assembly is directed into double-percolating networks, reducing the percolation threshold and enabling combined optical transparency and electrical conductivity not accessible in single-network materials. The resulting composites open new possibilities on the quest of transparent electrodes for photovoltaics, organic light-emitting diodes and stretchable optoelectronic devices.

  18. Phonon and magnetic structure in δ-plutonium from density-functional theory

    PubMed Central

    Söderlind, Per; Zhou, F.; Landa, A.; Klepeis, J. E.

    2015-01-01

    We present phonon properties of plutonium metal obtained from a combination of density-functional-theory (DFT) electronic structure and the recently developed compressive sensing lattice dynamics (CSLD). The CSLD model is here trained on DFT total energies of several hundreds of quasi-random atomic configurations for best possible accuracy of the phonon properties. The calculated phonon dispersions compare better with experiment than earlier results obtained from dynamical mean-field theory. The density-functional model of the electronic structure consists of disordered magnetic moments with all relativistic effects and explicit orbital-orbital correlations. The magnetic disorder is approximated in two ways: (i) a special quasi-random structure and (ii) the disordered-local-moment method within the coherent potential approximation. Magnetism in plutonium has been debated intensely, but the present magnetic approach for plutonium is validated by the close agreement between the predicted magnetic form factor and that of recent neutron-scattering experiments. PMID:26514238

  19. Hyperpolarized Magnetic Resonance as a Sensitive Detector of Metabolic Function

    PubMed Central

    2015-01-01

    Hyperpolarized magnetic resonance allows for noninvasive measurements of biochemical reactions in vivo. Although this technique provides a unique tool for assaying enzymatic activities in intact organs, the scope of its application is still elusive for the wider scientific community. The purpose of this review is to provide key principles and parameters to guide the researcher interested in adopting this technology to address a biochemical, biomedical, or medical issue. It is presented in the form of a compendium containing the underlying essential physical concepts as well as suggestions to help assess the potential of the technique within the framework of specific research environments. Explicit examples are used to illustrate the power as well as the limitations of hyperpolarized magnetic resonance. PMID:25369537

  20. Magnetic resonance imaging and electromyography as indexes of muscle function

    NASA Technical Reports Server (NTRS)

    Adams, Gregory R.; Duvoisin, Marc R.; Dudley, Gary A.

    1992-01-01

    A hypothesis is tested that exercise-induced magnetic resonance (MR) contrast shifts would relate to electromyography (EMG) amplitude if both measures reflect muscle use during exercise. Both magnetic resonance images (MRI) and EMG data were obtained for separate eccentric (ECC) and cocentric (CON) exercise of increasing intensity for seven subjects 30-32 yr old. CON and ECC actions caused increased integrated EMG (IEMG) and T2 values which were strongly related with relative resistance. The rate of increase and absolute value of both T2 and IEMG were found to be greater for CON than for ECC actions. For both actions IEMG and T2 were correlated. Data obtained suggest that surface IEMG accurately reflects the contractile behavior of muscle and exercise-induced increases in MRI T2 values reflect certain processes that scale with muscle use.

  1. Microwave absorption in nanocomposite material of magnetically functionalized carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Labunov, V. A.; Danilyuk, A. L.; Prudnikava, A. L.; Komissarov, I.; Shulitski, B. G.; Speisser, C.; Antoni, F.; Le Normand, F.; Prischepa, S. L.

    2012-07-01

    The interaction of electromagnetic radiation in X and Ka bands with magnetic nanocomposite of disordered carbon nanotubes arrays has been investigated both experimentally and theoretically. Samples were synthesized on the quartz reactor walls by decomposition of ferrocene and xylene which provided random intercalation of iron phase nanoparticles in carbon nanotube array. The exhaustive characterization of the samples by means of the scanning electron microscopy, Raman spectroscopy, and x-ray photoemission spectroscopy was performed. It was found that the absorption of the electromagnetic wave monotonically increases with the frequency. To describe these experimental data, we extended the Bruggeman effective medium theory to a more complex case of a magnetic nanocomposite with randomly distributed spherical ferromagnetic nanoparticles in a conducting medium. The essential feature of the developed model is the consideration of the complex nature of the studied material. In particular, such important parameters as magnetic and dielectric properties of both the carbon nanotube medium and the nanoparticles, the volume concentration and the dimensions of the nanoparticles, the wave impedance of the resistive-capacitive shells of the conductive nanoparticles are explicitly taken into account in our model. Moreover, analysing the experimental results, we were able to obtain the frequency dependencies of permittivity and permeability of the studied nanocomposite.

  2. Synthesis and design of functionalized magnetic nanocolloids for water pollution remediation

    NASA Astrophysics Data System (ADS)

    Campos, A. F. C.; Ferreira, M. A.; Marinho, E. P.; Tourinho, F. A.; Depeyrot, J.

    This work focus on the potential applications of magnetic nanoparticles on pollution remediation. We draw attention to the chemical design of functionalized magnetic colloids based on tartrate ligands to be used in magnetic separation of heavy metals from wastewater. Coupling the speciation diagrams of nanoferrites particles surface with that of the tartaric acid, it was possible to provide a theoretical prediction of the optimal pH for particle surface-ligand complexation. Finally, from an electrochemical approach based on simultaneous potentiometric and conductimetric titrations it was possible to determine the saturation value of the surface charge density of the functionalized nanoparticles and its pH dependence.

  3. THEORETICAL ESTIMATES OF TWO-POINT SHEAR CORRELATION FUNCTIONS USING TANGLED MAGNETIC FIELDS

    SciTech Connect

    Pandey, Kanhaiya L.; Sethi, Shiv K.

    2012-03-20

    The existence of primordial magnetic fields can induce matter perturbations with additional power at small scales as compared to the usual {Lambda}CDM model. We study its implication within the context of a two-point shear correlation function from gravitational lensing. We show that a primordial magnetic field can leave its imprints on the shear correlation function at angular scales {approx}< a few arcminutes. The results are compared with CFHTLS data, which yield some of the strongest known constraints on the parameters (strength and spectral index) of the primordial magnetic field. We also discuss the possibility of detecting sub-nano Gauss fields using future missions such as SNAP.

  4. Self-assembly with orthogonal-imposed stimuli to impart structure and confer magnetic function to electrodeposited hydrogels.

    PubMed

    Li, Ying; Liu, Yi; Gao, Tieren; Zhang, Boce; Song, Yingying; Terrell, Jessica L; Barber, Nathan; Bentley, William E; Takeuchi, Ichiro; Payne, Gregory F; Wang, Qin

    2015-05-20

    A magnetic nanocomposite film with the capability of reversibly collecting functionalized magnetic particles was fabricated by simultaneously imposing two orthogonal stimuli (electrical and magnetic). We demonstrate that cathodic codeposition of chitosan and Fe3O4 nanoparticles while simultaneously applying a magnetic field during codeposition can (i) organize structure, (ii) confer magnetic properties, and (iii) yield magnetic films that can perform reversible collection/assembly functions. The magnetic field triggered the self-assembly of Fe3O4 nanoparticles into hierarchical "chains" and "fibers" in the chitosan film. For controlled magnetic properties, the Fe3O4-chitosan film was electrodeposited in the presence of various strength magnetic fields and different deposition times. The magnetic properties of the resulting films should enable broad applications in complex devices. As a proof of concept, we demonstrate the reversible capture and release of green fluorescent protein (EGFP)-conjugated magnetic microparticles by the magnetic chitosan film. Moreover, antibody-functionalized magnetic microparticles were applied to capture cells from a sample, and these cells were collected, analyzed, and released by the magnetic chitosan film, paving the way for applications such as reusable biosensor interfaces (e.g., for pathogen detection). To our knowledge, this is the first report to apply a magnetic field during the electrodeposition of a hydrogel to generate magnetic soft matter. Importantly, the simple, rapid, and reagentless fabrication methodologies demonstrated here are valuable features for creating a magnetic device interface. PMID:25923335

  5. Electronic and magnetic properties of germanene: Surface functionalization and strain effects

    NASA Astrophysics Data System (ADS)

    Liang, Pei; Liu, Yang; Xing, Song; Shu, Haibo; Tai, Bo

    2016-01-01

    The surface functionalization and strain effects on the structural, electronic, and magnetic properties of full-/half-passivated germanenes are investigated systematically by the first-principle calculations within density functional theory. It is found that the germanenes with full-passivation have different band structures. i.e., the band-gap of GeH is larger than that of GeF and GeCl. Interestingly, when surface passivation and strain are utilized, germanenes go through a transformation from semiconductor to semi-metal. Moreover, germanenes with half-passivation present different magnetic characters, i.e,. Ge2H is a ferromagnetic semiconductor, while Ge2F and Ge2Cl are anti-ferromagnetic semiconductors. The stability of magnetic coupling of Ge2Xs can be modulated by external strain. Our calculations indicate that the electronic and magnetic properties of passivated-germanenes strongly depend on their surface functionalization and strain effects.

  6. Aspartame downregulates 3T3-L1 differentiation.

    PubMed

    Pandurangan, Muthuraman; Park, Jeongeun; Kim, Eunjung

    2014-10-01

    Aspartame is an artificial sweetener used as an alternate for sugar in several foods and beverages. Since aspartame is 200 times sweeter than traditional sugar, it can give the same level of sweetness with less substance, which leads to lower-calorie food intake. There are reports that consumption of aspartame-containing products can help obese people lose weight. However, the potential role of aspartame in obesity is not clear. The present study investigated whether aspartame suppresses 3T3-L1 differentiation, by downregulating phosphorylated peroxisome proliferator-activated receptor γ (p-PPARγ), peroxisome proliferator-activated receptor γ (PPARγ), fatty acid-binding protein 4 (FABP4), CCAAT/enhancer-binding protein α (C/EBPα), and sterol regulatory element-binding protein 1 (SREBP1), which are critical for adipogenesis. The 3T3-L1 adipocytes were cultured and differentiated for 6 d in the absence and presence of 10 μg/ml of aspartame. Aspartame reduced lipid accumulation in differentiated adipocytes as evidenced by Oil Red O staining. qRT-PCR analysis showed that the PPARγ, FABP4, and C/EBPα mRNA expression was significantly reduced in the aspartame-treated adipocytes. Western blot analysis showed that the induction of p-PPARγ, PPARγ, SREBP1, and adipsin was markedly reduced in the aspartame-treated adipocytes. Taken together, these data suggest that aspartame may be a potent substance to alter adipocyte differentiation and control obesity. PMID:24961835

  7. Aspartame downregulates 3T3-L1 differentiation.

    PubMed

    Pandurangan, Muthuraman; Park, Jeongeun; Kim, Eunjung

    2014-10-01

    Aspartame is an artificial sweetener used as an alternate for sugar in several foods and beverages. Since aspartame is 200 times sweeter than traditional sugar, it can give the same level of sweetness with less substance, which leads to lower-calorie food intake. There are reports that consumption of aspartame-containing products can help obese people lose weight. However, the potential role of aspartame in obesity is not clear. The present study investigated whether aspartame suppresses 3T3-L1 differentiation, by downregulating phosphorylated peroxisome proliferator-activated receptor γ (p-PPARγ), peroxisome proliferator-activated receptor γ (PPARγ), fatty acid-binding protein 4 (FABP4), CCAAT/enhancer-binding protein α (C/EBPα), and sterol regulatory element-binding protein 1 (SREBP1), which are critical for adipogenesis. The 3T3-L1 adipocytes were cultured and differentiated for 6 d in the absence and presence of 10 μg/ml of aspartame. Aspartame reduced lipid accumulation in differentiated adipocytes as evidenced by Oil Red O staining. qRT-PCR analysis showed that the PPARγ, FABP4, and C/EBPα mRNA expression was significantly reduced in the aspartame-treated adipocytes. Western blot analysis showed that the induction of p-PPARγ, PPARγ, SREBP1, and adipsin was markedly reduced in the aspartame-treated adipocytes. Taken together, these data suggest that aspartame may be a potent substance to alter adipocyte differentiation and control obesity.

  8. Cannabidiol promotes browning in 3T3-L1 adipocytes.

    PubMed

    Parray, Hilal Ahmad; Yun, Jong Won

    2016-05-01

    Recruitment of the brown-like phenotype in white adipocytes (browning) and activation of existing brown adipocytes are currently being investigated as a means to combat obesity. Thus, a wide variety of dietary agents that contribute to browning of white adipocytes have been identified. The present study was designed to investigate the effects of cannabidiol (CBD), a major nonpsychotropic phytocannabinoid of Cannabis sativa, on induction of browning in 3T3-L1 adipocytes. CBD enhanced expression of a core set of brown fat-specific marker genes (Ucp1, Cited1, Tmem26, Prdm16, Cidea, Tbx1, Fgf21, and Pgc-1α) and proteins (UCP1, PRDM16, and PGC-1α). Increased expression of UCP1 and other brown fat-specific markers contributed to the browning of 3T3-L1 adipocytes possibly via activation of PPARγ and PI3K. In addition, CBD increased protein expression levels of CPT1, ACSL, SIRT1, and PLIN while down-regulating JNK2, SREBP1, and LPL. These data suggest possible roles for CBD in browning of white adipocytes, augmentation of lipolysis, thermogenesis, and reduction of lipogenesis. In conclusion, the current data suggest that CBD plays dual modulatory roles in the form of inducing the brown-like phenotype as well as promoting lipid metabolism. Thus, CBD may be explored as a potentially promising therapeutic agent for the prevention of obesity. PMID:27067870

  9. Large Gradient High Magnetic Fields Affect Osteoblast Ultrastructure and Function by Disrupting Collagen I or Fibronectin/αβ1 Integrin

    PubMed Central

    Qian, Ai-Rong; Gao, Xiang; Zhang, Wei; Li, Jing-Bao; Wang, Yang; Di, Sheng-Meng; Hu, Li-Fang; Shang, Peng

    2013-01-01

    The superconducting magnet generates a field and field gradient product that can levitate diamagnetic materials. In this study a specially designed superconducting magnet with a large gradient high magnetic field (LG-HMF), which can provide three apparent gravity levels (μ-g, 1-g, and 2-g), was used to simulate a space-like gravity environment. The effects of LG-HMF on the ultrastructure and function of osteoblast-like cells (MG-63 and MC3T3-E1) and the underlying mechanism were investigated by transmission electromicroscopy (TEM), MTT, and cell western (ICW) assays. Under LG-HMF significant morphologic changes in osteoblast-like cells occurred, including expansion of endoplasmic reticulum and mitochondria, an increased number of lysosomes, distorted microvilli, and aggregates of actin filaments. Compared to controls, cell viability and alkaline phosphatase (ALP) secretion were significantly increased, and collagen I (col I), fibronectin (FN), vinculin, integrin α3, αv, and β1 expression were changed under LG-HMF conditions. In conclusion, LG-HMF affects osteoblast ultrastructure, cell viability, and ALP secretion, and the changes caused by LG-HMF may be related to disrupting col I or FN/αβ1 integrin. PMID:23382804

  10. Non-Invasive Functional Mapping of the Brain Using Magnetoencephalography and Functional Magnetic Resonance Imaging.

    NASA Astrophysics Data System (ADS)

    Wang, Jihong

    Magnetoencephalography (MEG) and Functional Magnetic Resonance Imaging (FMRI) are two non-invasive techniques that can be used to study brain function. The first part of this dissertation discusses experimental factors that affect the accuracy of MEG source localization. These factors include measurement error, signal to noise ratio, number of measurement points and the local curvature of the head. A skull phantom and computer simulation were used to study the accuracy of MEG localization. It was found that the MEG dipole localization error was approximately 5-10 mm in the temporal region. This localization error was directly proportional to the digitization error. An empirical formula is given for the dependence of the MEG localization accuracy on the signal to noise ratio. The dependence of the MEG localization accuracy on the number of measurement points was also studied. Adequate coverage of extrema is necessary for accurate dipole localizations. The local curvature of the head does not affect localization accuracy as long as the center of the best fit sphere to this local surface is within 4 cm of the center of the best fit sphere to the whole head. The second part of the dissertation presents MEG and FMRI results of motor and auditory stimulation. It was found that the locations of auditory and motor activities as identified by MEG were in agreement with those identified by FMRI within 1-2 cm. The reasons for this discrepancy are discussed. The successful FMRI during auditory stimulation is reported. The fundamental aspects of the MEG inverse solution are discussed and a new spatiotemporal inverse solution algorithm is proposed.

  11. Longitudinal wave function control in single quantum dots with an applied magnetic field.

    PubMed

    Cao, Shuo; Tang, Jing; Gao, Yunan; Sun, Yue; Qiu, Kangsheng; Zhao, Yanhui; He, Min; Shi, Jin-An; Gu, Lin; Williams, David A; Sheng, Weidong; Jin, Kuijuan; Xu, Xiulai

    2015-01-01

    Controlling single-particle wave functions in single semiconductor quantum dots is in demand to implement solid-state quantum information processing and spintronics. Normally, particle wave functions can be tuned transversely by an perpendicular magnetic field. We report a longitudinal wave function control in single quantum dots with a magnetic field. For a pure InAs quantum dot with a shape of pyramid or truncated pyramid, the hole wave function always occupies the base because of the less confinement at base, which induces a permanent dipole oriented from base to apex. With applying magnetic field along the base-apex direction, the hole wave function shrinks in the base plane. Because of the linear changing of the confinement for hole wave function from base to apex, the center of effective mass moves up during shrinking process. Due to the uniform confine potential for electrons, the center of effective mass of electrons does not move much, which results in a permanent dipole moment change and an inverted electron-hole alignment along the magnetic field direction. Manipulating the wave function longitudinally not only provides an alternative way to control the charge distribution with magnetic field but also a new method to tune electron-hole interaction in single quantum dots. PMID:25624018

  12. Longitudinal wave function control in single quantum dots with an applied magnetic field

    PubMed Central

    Cao, Shuo; Tang, Jing; Gao, Yunan; Sun, Yue; Qiu, Kangsheng; Zhao, Yanhui; He, Min; Shi, Jin-An; Gu, Lin; Williams, David A.; Sheng, Weidong; Jin, Kuijuan; Xu, Xiulai

    2015-01-01

    Controlling single-particle wave functions in single semiconductor quantum dots is in demand to implement solid-state quantum information processing and spintronics. Normally, particle wave functions can be tuned transversely by an perpendicular magnetic field. We report a longitudinal wave function control in single quantum dots with a magnetic field. For a pure InAs quantum dot with a shape of pyramid or truncated pyramid, the hole wave function always occupies the base because of the less confinement at base, which induces a permanent dipole oriented from base to apex. With applying magnetic field along the base-apex direction, the hole wave function shrinks in the base plane. Because of the linear changing of the confinement for hole wave function from base to apex, the center of effective mass moves up during shrinking process. Due to the uniform confine potential for electrons, the center of effective mass of electrons does not move much, which results in a permanent dipole moment change and an inverted electron-hole alignment along the magnetic field direction. Manipulating the wave function longitudinally not only provides an alternative way to control the charge distribution with magnetic field but also a new method to tune electron-hole interaction in single quantum dots. PMID:25624018

  13. High-permeability functionalized silicone magnetic microspheres with low autofluorescence for biomedical applications.

    PubMed

    Evans, Benjamin A; Ronecker, Julia C; Han, David T; Glass, Daniel R; Train, Tonya L; Deatsch, Alison E

    2016-05-01

    Functionalized magnetic microspheres are widely used for cell separations, isolation of proteins and other biomolecules, in vitro diagnostics, tissue engineering, and microscale force spectroscopy. We present here the synthesis and characterization of a silicone magnetic microsphere which can be produced in diameters ranging from 0.5 to 50 μm via emulsion polymerization of a silicone ferrofluid precursor. This bottom-up approach to synthesis ensures a uniform magnetic concentration across all sizes, leading to significant advances in magnetic force generation. We demonstrate that in a size range of 5-20 μm, these spheres supply a full order of magnitude greater magnetic force than leading commercial products. In addition, the unique silicone matrix exhibits autofluorescence two orders of magnitude lower than polystyrene microspheres. Finally, we demonstrate the ability to chemically functionalize our silicone microspheres using a standard EDC reaction, and show that our folate-functionalized silicone microspheres specifically bind to targeted HeLa and Jurkat cells. These spheres show tremendous potential for replacing magnetic polystyrene spheres in applications which require either large magnetic forces or minimal autofluorescence, since they represent order-of-magnitude improvements in each. In addition, the unique silicone matrix and proven biocompatibility suggest that they may be useful for encapsulation and targeted delivery of lipophilic pharmaceuticals. PMID:26952493

  14. Structure, function, and use of the magnetic sense in animals (invited)

    NASA Astrophysics Data System (ADS)

    Walker, Michael M.; Diebel, Carol E.; Green, Colin R.

    2000-05-01

    The hypothesis that animals navigate magnetically is attractive because the earth's magnetic field provides consistent information about position and direction in all environments through which animals travel. However, the hypothesis has been difficult to test because (i) the structure and function of the sense could not readily be analyzed in the laboratory and (ii) the effects of experimental treatments on behavior in the laboratory and field could not be reliably predicted. Our research is focused on the structure and function of the sense in rainbow trout and on applying the understanding gained in the laboratory to studies of navigation by homing pigeons. We have found iron-rich crystals (most likely single-domain magnetite) in candidate magnetoreceptor cells located within a discrete layer of sensory tissue in the nose of rainbow trout. The candidate receptor cells are closely associated with a branch of the trigeminal nerve that responds to changes in intensity but not direction of magnetic fields. In parallel work, we have developed a model of magnetic position determination in which pigeons derive magnetic analogues of geographic latitude and longitude from (i) the total intensity and (ii) the direction of the intensity slope of the earth's magnetic field. Taken together with our other results, the model gives us confidence that a coherent understanding of the structure, function, and use of the magnetic sense in animals is now developing.

  15. Cyclosporine A prevents the generation of single positive (Lyt2+ L3T4-, Lyt2- L3T4+) mature T cells, but not single positive (Lyt2+ T3-) Immature thymocytes, in newborn mice.

    PubMed

    Heeg, K; Bendigs, S; Wagner, H

    1989-12-01

    The influence of cyclosporine A (CsA) on T-cell maturation was investigated in newborn mice. CsA treatment during the pre- and postnatal periods resulted in a hypoplasia of peripheral lymphatic organs, and absence of mature T3+ T cells in lymph nodes and spleens; no functional T-cell reactivity was observed. In thymuses of CsA-treated mice, no T3+ single positive Lyt2+ or T3+L3T4+ thymocytes could be found, but double positive (DP) cells were readily detected. A thymocyte subset with the phenotype Lyt2+L3T4-T3- was still discernible; this population was non-functional in vitro. The data show that the maturation of single positive (SP) T cells is critically influenced by CsA; under the conditions used here we found no evidence that 'leaky' autoreactive SP T cells develop in CsA-treated newborn mice.

  16. Sclerostin Enhances Adipocyte Differentiation in 3T3-L1 Cells.

    PubMed

    Ukita, Mayumi; Yamaguchi, Taihiko; Ohata, Noboru; Tamura, Masato

    2016-06-01

    Sclerostin, a secreted protein encoded by the Sost gene, is produced by osteocytes and is inhibited by osteoblast differentiation and bone formation. Recently, a functional association between bone and fat tissue has been suggested, and a correlation between circulating sclerostin levels and lipid metabolism has been reported in humans. However, the effects of sclerostin on adipogenesis remain unexplored. In the present study, we examined the role of sclerostin in regulating adipocyte differentiation using 3T3-L1 preadipocytes. In these cells, sclerostin enhanced adipocyte-specific gene expression and the accumulation of lipid deposits. Sclerostin also upregulated CCAAT/enhancer binding protein β expression but not cell proliferation and caspase-3/7 activities. Sclerostin also attenuated canonical Wnt3a-inhibited adipocyte differentiation. Recently, the transcriptional modulator TAZ has been involved in the canonical Wnt signaling pathway. Sclerostin reduced TAZ-responsive transcriptional activity and TAZ-responsive gene expression. Transfection of 3T3-L1 cells with TAZ siRNA increased the lipid deposits and adipogenic gene expression. These results show that sclerostin upregulates adipocyte differentiation in 3T3-L1 cells, suggesting a possible role for the osteocyte-derived sclerostin as a regulator of fat metabolism and as a reciprocal regulator of bone and adipose tissues metabolism.

  17. Ginkgolide C Suppresses Adipogenesis in 3T3-L1 Adipocytes via the AMPK Signaling Pathway.

    PubMed

    Liou, Chian-Jiun; Lai, Xuan-Yu; Chen, Ya-Ling; Wang, Chia-Ling; Wei, Ciao-Han; Huang, Wen-Chung

    2015-01-01

    Ginkgolide C, isolated from Ginkgo biloba leaves, is a flavone reported to have multiple biological functions, from decreased platelet aggregation to ameliorating Alzheimer disease. The study aim was to evaluate the antiadipogenic effect of ginkgolide C in 3T3-L1 adipocytes. Ginkgolide C was used to treat differentiated 3T3-L1 cells. Cell supernatant was collected to assay glycerol release, and cells were lysed to measure protein and gene expression related to adipogenesis and lipolysis by western blot and real-time PCR, respectively. Ginkgolide C significantly suppressed lipid accumulation in differentiated adipocytes. It also decreased adipogenesis-related transcription factor expression, including peroxisome proliferator-activated receptor and CCAAT/enhancer-binding protein. Furthermore, ginkgolide C enhanced adipose triglyceride lipase and hormone-sensitive lipase production for lipolysis and increased phosphorylation of AMP-activated protein kinase (AMPK), resulting in decreased activity of acetyl-CoA carboxylase for fatty acid synthesis. In coculture with an AMPK inhibitor (compound C), ginkgolide C also improved activation of sirtuin 1 and phosphorylation of AMPK in differentiated 3T3-L1 cells. The results suggest that ginkgolide C is an effective flavone for increasing lipolysis and inhibiting adipogenesis in adipocytes through the activated AMPK pathway.

  18. Ginkgolide C Suppresses Adipogenesis in 3T3-L1 Adipocytes via the AMPK Signaling Pathway

    PubMed Central

    Liou, Chian-Jiun; Lai, Xuan-Yu; Chen, Ya-Ling; Wang, Chia-Ling; Wei, Ciao-Han; Huang, Wen-Chung

    2015-01-01

    Ginkgolide C, isolated from Ginkgo biloba leaves, is a flavone reported to have multiple biological functions, from decreased platelet aggregation to ameliorating Alzheimer disease. The study aim was to evaluate the antiadipogenic effect of ginkgolide C in 3T3-L1 adipocytes. Ginkgolide C was used to treat differentiated 3T3-L1 cells. Cell supernatant was collected to assay glycerol release, and cells were lysed to measure protein and gene expression related to adipogenesis and lipolysis by western blot and real-time PCR, respectively. Ginkgolide C significantly suppressed lipid accumulation in differentiated adipocytes. It also decreased adipogenesis-related transcription factor expression, including peroxisome proliferator-activated receptor and CCAAT/enhancer-binding protein. Furthermore, ginkgolide C enhanced adipose triglyceride lipase and hormone-sensitive lipase production for lipolysis and increased phosphorylation of AMP-activated protein kinase (AMPK), resulting in decreased activity of acetyl-CoA carboxylase for fatty acid synthesis. In coculture with an AMPK inhibitor (compound C), ginkgolide C also improved activation of sirtuin 1 and phosphorylation of AMPK in differentiated 3T3-L1 cells. The results suggest that ginkgolide C is an effective flavone for increasing lipolysis and inhibiting adipogenesis in adipocytes through the activated AMPK pathway. PMID:26413119

  19. Magnetizing of permanent magnets using HTS bulk magnets

    NASA Astrophysics Data System (ADS)

    Oka, Tetsuo; Muraya, Tomoki; Kawasaki, Nobutaka; Fukui, Satoshi; Ogawa, Jun; Sato, Takao; Terasawa, Toshihisa

    2012-01-01

    A demagnetized Nd-Fe-B permanent magnet was scanned just above the magnetic pole which contains the HTS bulk magnet generating a magnetic field of 3.27 T. The magnet sample was subsequently found to be fully magnetized in the open space of the static magnetic fields. We examined the magnetic field distributions when the magnetic poles were scanned twice to activate the magnet plate inversely with various overlap distances between the tracks of the bulk magnet. The magnetic field of the "rewritten" magnet reached the values of the magnetically saturated region of the material, showing steep gradients at the border of each magnetic pole. As a replacement for conventional pulse field magnetizing methods, this technique is proposed to expand the degree of freedom in the design of electromagnetic devices, and is proposed as a novel practical method for magnetizing rare-earth magnets, which have excellent magnetic performance and require intense fields of more than 3 T to be activated.

  20. Effects of the substrate on graphone magnetism: A density functional theory study

    NASA Astrophysics Data System (ADS)

    Buonocore, Francesco; Mosca Conte, Adriano; Lisi, Nicola

    2016-04-01

    The magnetism of graphone, a single-side-hydrogenated graphene derivative, has been related to the localized and unpaired p-electrons associated with the unhydrogenated carbon atoms. In the present density functional theory study, the effects the adhesion to either Cu(111) or α-quartz (0001) surface on the magnetic properties of graphone have been investigated. The total magnetization of the graphone adsorbed to copper and quartz surface is reduced by four and two times, respectively, with respect to the isolated graphone. We have shown there is electronic charge transfer from surface towards three-fold coordinated C atoms of graphone, but the main role in the partial magnetism quenching is played by bond formation and the consequent electron pairing of p-electrons. The critical temperature has been investigated on the basis of the mean field theory to evaluate the stability of the magnetism at ordinary temperature.

  1. Multi-functional Magnetic Nanoparticles for Magnetic Resonance Imaging and Cancer Therapy

    PubMed Central

    Yallapu, Murali M.; Othman, Shadi F.; Curtis, Evan T.; Gupta, Brij K.; Jaggi, Meena; Chauhan, Subhash C.

    2010-01-01

    We have developed a multi-layer approach for the synthesis of water-dispersible superparamagnetic iron oxide nanoparticles for hyperthermia, magnetic resonance imaging (MRI) and drug delivery applications. In this approach, iron oxide core nanoparticles were obtained by precipitation of iron salts in the presence of ammonia and provided β-cyclodextrin and pluronic polymer (F127) coatings. This formulation (F127250) was highly water dispersible which allowed encapsulation of the anti-cancer drug(s) in β-cyclodextrin and pluronic polymer for sustained drug release. The F127250 formulation has exhibited superior hyperthermia effects over time under alternating magnetic field compared to pure magnetic nanoparticles (MNP) and β-cyclodextrin coated nanoparticles (CD200). Additionally, the improved MRI characteristics were also observed for the F127250 formulation in agar gel and in cisplatin resistant ovarian cancer cells (A12780CP) compared to MNP and CD200 formulations. Furthermore, the drug loaded formulation of F127250 exhibited many folds of imaging contrast properties. Due to the internalization capacity of the F127250 formulation, its curcumin loaded formulation (F127250-CUR) exhibited almost equivalent inhibition effects on A2780CP (ovarian), MDA-MB-231 (breast), and PC3 (prostate) cancer cells even though curcumin release was only 40%. The improved therapeutic effects were verified by examining molecular effects using Western blotting and transmission electron microscopic (TEM) studies. F127250-CUR also exhibited haemocompatibility, suggesting a nanochemo-therapuetic agent for cancer therapy. PMID:21167595

  2. Brain Activation during Semantic Processing in Autism Spectrum Disorders via Functional Magnetic Resonance Imaging

    ERIC Educational Resources Information Center

    Harris, Gordon J.; Chabris, Christopher F.; Clark, Jill; Urban, Trinity; Aharon, Itzhak; Steele, Shelley; McGrath, Lauren; Condouris, Karen; Tager-Flusberg, Helen

    2006-01-01

    Language and communication deficits are core features of autism spectrum disorders (ASD), even in high-functioning adults with ASD. This study investigated brain activation patterns using functional magnetic resonance imaging in right-handed adult males with ASD and a control group, matched on age, handedness, and verbal IQ. Semantic processing in…

  3. Uniform DT 3T burn: computations and sensitivities

    SciTech Connect

    Vold, Erik; Hryniw, Natalia; Hansen, Jon A; Kesler, Leigh A; Li, Frank

    2011-01-27

    A numerical model was developed in C to integrate the nonlinear deutrium-tritium (DT) burn equations in a three temperature (3T) approximation for spatially uniform test problems relevant to Inertial Confinement Fusion (ICF). Base model results are in excellent agreement with standard 3T results. Data from NDI, SESAME, and TOPS databases is extracted to create fits for the reaction rate parameter, the Planck opacity, and the coupling frequencies of the plasma temperatures. The impact of different fits (e.g., TOPS versus SESAME opacity data, higher order polynomial fits ofNDI data for the reaction rate parameter) were explored, and sensitivity to several model inputs are presented including: opacity data base, Coulomb logarithm, and Bremsstrahlung. Sensitivity to numerical integration time step size, and the relative insensitivity to the discretized numerics and numerical integration method was demonstrated. Variations in the IC for densities and temperatures were explored, showing similar DT burn profiles in most cases once ignition occurs. A coefficient multiplying the Compton coupling term (default, A = 1) can be adjusted to approximate results from more sophisticated models. The coefficient was reset (A = 0.4) to match the maximum temperatures resulting from standard multi-group simulations of the base case test problem. Setting the coefficient to a larger value, (A = 0.6) matches maximum ion temperatures in a kinetic simulation of a high density ICF-like regime. Matching peak temperatures does not match entire temperature-time profiles, indicating the Compton coefficient is density and time dependent as the photon distribution evolves. In the early time burn during the ignition of the DT, the present model with modified Compton coupling provides a very simple method to obtain a much improved match to the more accurate solution from the multi-group radiation model for these DT burn regimes.

  4. Magnetic probe response function calibrations for plasma equilibrium reconstructions of CDX-U

    SciTech Connect

    Spaleta, J.; Zakharov, L.; Kaita, R.; Majeski, R.; Gray, T.

    2006-10-15

    A novel response function calibration technique has been developed to account for time-dependent nonaxisymmetric eddy currents near magnetic sensors in toroidal magnetic confinement devices. The response function technique provides a means to cross calibrate against all available external field coil systems to calculate the absolute sensitivity of each magnetic field sensor, even when induced eddy currents are present in the vacuum vessel wall. The response function information derived in the calibration process can be used in equilibrium reconstructions to separate plasma signals from signals due to externally produced eddy currents at magnetic field sensor locations, without invoking localized wall current distribution details. The response function technique was used for the first ever equilibrium reconstructions of spherical torus plasmas, when applied to the Current Drive Experiment-Upgrade (CDX-U) device. In conjunction with the equilibrium and stability code (ESC), equilibria were obtained for recent CDX-U experiments with lithium plasma-facing components. A description of the CDX-U magnetic sensor configuration and the response function calibration technique will be presented along with examples of resulting plasma equilibrium for CDX-U lithium wall operations.

  5. Precise response function for the magnetic component of gravitational waves in scalar-tensor gravity

    SciTech Connect

    Corda, Christian

    2011-03-15

    The important issue of the magnetic component of gravitational waves (GWs) has been considered in various papers in the literature. From such analyses, it has been found that such a magnetic component becomes particularly important in the high-frequency portion of the frequency range of ground based interferometers for GWs which arises from standard general theory of relativity (GTR). Recently, such a magnetic component has been extended to GWs arising from scalar-tensor gravity (STG) too. After a review of some important issues on GWs in STG, in this paper we reanalyze the magnetic component in the framework of STG from a different point of view, by correcting an error in a previous paper and by releasing a more precise response function. In this way, we also show that if one neglects the magnetic contribution considering only the low-frequency approximation of the electric contribution, an important part of the signal could be, in principle, lost. The determination of a more precise response function for the magnetic contribution is important also in the framework of the possibility of distinguishing other gravitational theories from GTR. At the conclusion of this paper, an expansion of the main results is also shown in order to recall the presence of the magnetic component in GTR too.

  6. Advances in functional magnetic resonance imaging: technology and clinical applications.

    PubMed

    Dickerson, Bradford C

    2007-07-01

    Functional MRI (fMRI) is a valuable method for use by clinical investigators to study task-related brain activation in patients with neurological or neuropsychiatric illness. Despite the relative infancy of the field, the rapid adoption of this functional neuroimaging technology has resulted from, among other factors, its ready availability, its relatively high spatial and temporal resolution, and its safety as a noninvasive imaging tool that enables multiple repeated scans over the course of a longitudinal study, and thus may lend itself well as a measure in clinical drug trials. Investigators have used fMRI to identify abnormal functional brain activity during task performance in a variety of patient populations, including those with neurodegenerative, demyelinating, cerebrovascular, and other neurological disorders that highlight the potential utility of fMRI in both basic and clinical spheres of research. In addition, fMRI studies reveal processes related to neuroplasticity, including compensatory hyperactivation, which may be a universally-occurring, adaptive neural response to insult. Functional MRI is being used to study the modulatory effects of genetic risk factors for neurological disease on brain activation; it is being applied to differential diagnosis, as a predictive biomarker of disease course, and as a means to identify neural correlates of neurotherapeutic interventions. Technological advances are rapidly occurring that should provide new applications for fMRI, including improved spatial resolution, which promises to reveal novel insights into the function of fine-scale neural circuitry of the human brain in health and disease.

  7. Nanometric resolution magnetic resonance imaging methods for mapping functional activity in neuronal networks

    PubMed Central

    Boretti, Albert; Castelletto, Stefania

    2016-01-01

    This contribution highlights and compares some recent achievements in the use of k-space and real space imaging (scanning probe and wide-filed microscope techniques), when applied to a luminescent color center in diamond, known as nitrogen vacancy (NV) center. These techniques combined with the optically detected magnetic resonance of NV, provide a unique platform to achieve nanometric magnetic resonance imaging (MRI) resolution of nearby nuclear spins (known as nanoMRI), and nanometric NV real space localization. • Atomic size optically detectable spin probe. • High magnetic field sensitivity and nanometric resolution. • Non-invasive mapping of functional activity in neuronal networks. PMID:27144128

  8. Nanometric resolution magnetic resonance imaging methods for mapping functional activity in neuronal networks.

    PubMed

    Boretti, Albert; Castelletto, Stefania

    2016-01-01

    This contribution highlights and compares some recent achievements in the use of k-space and real space imaging (scanning probe and wide-filed microscope techniques), when applied to a luminescent color center in diamond, known as nitrogen vacancy (NV) center. These techniques combined with the optically detected magnetic resonance of NV, provide a unique platform to achieve nanometric magnetic resonance imaging (MRI) resolution of nearby nuclear spins (known as nanoMRI), and nanometric NV real space localization. •Atomic size optically detectable spin probe.•High magnetic field sensitivity and nanometric resolution.•Non-invasive mapping of functional activity in neuronal networks. PMID:27144128

  9. Nanometric resolution magnetic resonance imaging methods for mapping functional activity in neuronal networks.

    PubMed

    Boretti, Albert; Castelletto, Stefania

    2016-01-01

    This contribution highlights and compares some recent achievements in the use of k-space and real space imaging (scanning probe and wide-filed microscope techniques), when applied to a luminescent color center in diamond, known as nitrogen vacancy (NV) center. These techniques combined with the optically detected magnetic resonance of NV, provide a unique platform to achieve nanometric magnetic resonance imaging (MRI) resolution of nearby nuclear spins (known as nanoMRI), and nanometric NV real space localization. •Atomic size optically detectable spin probe.•High magnetic field sensitivity and nanometric resolution.•Non-invasive mapping of functional activity in neuronal networks.

  10. Electron Velocity Distribution Function in Magnetic Clouds in the Solar Wind

    NASA Technical Reports Server (NTRS)

    Nieves-Chinchil, Teresa; Vinas, Adolfo F.; Bale, Stuart D.

    2006-01-01

    We present a study of the kinetic properties of the electron velocity distribution functions within magnetic clouds, since they are the dominant thermal component. The study is based on high time resolution data from the GSFC WIND/SWE electron spectrometer and the Berkeley 3DP electron plasma instruments. Recent studies on magnetic clouds have shown observational evidence of anti-correlation between the total electron density and electron temperature, which suggest a polytrope law P(sub e) = alpha(Nu(sub e) (sup gamma)) for electrons with the constant gamma approximates 0.5 < 1. This anti-correlation and small polytropic gamma-values is interpreted in the context of the presence of highly non-Maxwellian electron distributions (i.e. non-thermal) within magnetic clouds. These works suggested that the non-thermal electrons can contribute as much as 50% of the total electron pressure within magnetic clouds. We have revisited some of the magnetic cloud events previously studied and attempted to quantify the nature of the non-thermal electrons by modeling the electron velocity distribution function using a kappa distribution function to characterize the kinetic non-thermal effects. If non-thermal tail effects are the source for the anti-correlation between the moment electron temperature and density and if the kappa distribution is a reasonable representative model of non-thermal effects, then the electron velocity distribution within magnetic clouds should show indication for small K-values when gamma < 1.

  11. Tailored functionalization of iron oxide nanoparticles for MRI, drug delivery, magnetic separation and immobilization of biosubstances.

    PubMed

    Hola, Katerina; Markova, Zdenka; Zoppellaro, Giorgio; Tucek, Jiri; Zboril, Radek

    2015-11-01

    In this critical review, we outline various covalent and non-covalent approaches for the functionalization of iron oxide nanoparticles (IONPs). Tuning the surface chemistry and design of magnetic nanoparticles are described in relation to their applicability in advanced medical technologies and biotechnologies including magnetic resonance imaging (MRI) contrast agents, targeted drug delivery, magnetic separations and immobilizations of proteins, enzymes, antibodies, targeting agents and other biosubstances. We review synthetic strategies for the controlled preparation of IONPs modified with frequently used functional groups including amine, carboxyl and hydroxyl groups as well as the preparation of IONPs functionalized with other species, e.g., epoxy, thiol, alkane, azide, and alkyne groups. Three main coupling strategies for linking IONPs with active agents are presented: (i) chemical modification of amine groups on the surface of IONPs, (ii) chemical modification of bioactive substances (e.g. with fluorescent dyes), and (iii) the activation of carboxyl groups mainly for enzyme immobilization. Applications for drug delivery using click chemistry linking or biodegradable bonds are compared to non-covalent methods based on polymer modified condensed magnetic nanoclusters. Among many challenges, we highlight the specific surface engineering allowing both therapeutic and diagnostic applications (theranostics) of IONPs and magnetic/metallic hybrid nanostructures possessing a huge potential in biocatalysis, green chemistry, magnetic bioseparations and bioimaging. PMID:25689073

  12. Tailored functionalization of iron oxide nanoparticles for MRI, drug delivery, magnetic separation and immobilization of biosubstances.

    PubMed

    Hola, Katerina; Markova, Zdenka; Zoppellaro, Giorgio; Tucek, Jiri; Zboril, Radek

    2015-11-01

    In this critical review, we outline various covalent and non-covalent approaches for the functionalization of iron oxide nanoparticles (IONPs). Tuning the surface chemistry and design of magnetic nanoparticles are described in relation to their applicability in advanced medical technologies and biotechnologies including magnetic resonance imaging (MRI) contrast agents, targeted drug delivery, magnetic separations and immobilizations of proteins, enzymes, antibodies, targeting agents and other biosubstances. We review synthetic strategies for the controlled preparation of IONPs modified with frequently used functional groups including amine, carboxyl and hydroxyl groups as well as the preparation of IONPs functionalized with other species, e.g., epoxy, thiol, alkane, azide, and alkyne groups. Three main coupling strategies for linking IONPs with active agents are presented: (i) chemical modification of amine groups on the surface of IONPs, (ii) chemical modification of bioactive substances (e.g. with fluorescent dyes), and (iii) the activation of carboxyl groups mainly for enzyme immobilization. Applications for drug delivery using click chemistry linking or biodegradable bonds are compared to non-covalent methods based on polymer modified condensed magnetic nanoclusters. Among many challenges, we highlight the specific surface engineering allowing both therapeutic and diagnostic applications (theranostics) of IONPs and magnetic/metallic hybrid nanostructures possessing a huge potential in biocatalysis, green chemistry, magnetic bioseparations and bioimaging.

  13. Physiological Noise Reduction Using Volumetric Functional Magnetic Resonance Inverse Imaging

    PubMed Central

    Lin, Fa-Hsuan; Nummenmaa, Aapo; Witzel, Thomas; Polimeni, Jonathan R.; Zeffiro, Thomas A.; Wang, Fu-Nien; Belliveau, John W.

    2013-01-01

    Physiological noise arising from a variety of sources can significantly degrade the detection of task-related activity in BOLD-contrast fMRI experiments. If whole head spatial coverage is desired, effective suppression of oscillatory physiological noise from cardiac and respiratory fluctuations is quite difficult without external monitoring, since traditional EPI acquisition methods cannot sample the signal rapidly enough to satisfy the Nyquist sampling theorem, leading to temporal aliasing of noise. Using a combination of high speed magnetic resonance inverse imaging (InI) and digital filtering, we demonstrate that it is possible to suppress cardiac and respiratory noise without auxiliary monitoring, while achieving whole head spatial coverage and reasonable spatial resolution. Our systematic study of the effects of different moving average (MA) digital filters demonstrates that a MA filter with a 2 s window can effectively reduce the variance in the hemodynamic baseline signal, thereby achieving 57-58% improvements in peak z-statistic values compared to unfiltered InI or spatially smoothed EPI data (FWHM =8.6 mm). In conclusion, the high temporal sampling rates achievable with InI permit significant reductions in physiological noise using standard temporal filtering techniques that result in significant improvements in hemodynamic response estimation. PMID:21954026

  14. A comprehensive neuropsychological mapping battery for functional magnetic resonance imaging.

    PubMed

    Karakas, Sirel; Baran, Zeynel; Ceylan, Arzu Ozkan; Tileylioglu, Emre; Tali, Turgut; Karakas, Hakki Muammer

    2013-11-01

    Existing batteries for FMRI do not precisely meet the criteria for comprehensive mapping of cognitive functions within minimum data acquisition times using standard scanners and head coils. The goal was to develop a battery of neuropsychological paradigms for FMRI that can also be used in other brain imaging techniques and behavioural research. Participants were 61 healthy, young adult volunteers (48 females and 13 males, mean age: 22.25 ± 3.39 years) from the university community. The battery included 8 paradigms for basic (visual, auditory, sensory-motor, emotional arousal) and complex (language, working memory, inhibition/interference control, learning) cognitive functions. Imaging was performed using standard functional imaging capabilities (1.5-T MR scanner, standard head coil). Structural and functional data series were analysed using Brain Voyager QX2.9 and Statistical Parametric Mapping-8. For basic processes, activation centres for individuals were within a distance of 3-11 mm of the group centres of the target regions and for complex cognitive processes, between 7 mm and 15 mm. Based on fixed-effect and random-effects analyses, the distance between the activation centres was 0-4 mm. There was spatial variability between individual cases; however, as shown by the distances between the centres found with fixed-effect and random-effects analyses, the coordinates for individual cases can be used to represent those of the group. The findings show that the neuropsychological brain mapping battery described here can be used in basic science studies that investigate the relationship of the brain to the mind and also as functional localiser in clinical studies for diagnosis, follow-up and pre-surgical mapping.

  15. ``Green'' functionalization of magnetic nanoparticles via tea polyphenol for magnetic resonance/fluorescent dual-imaging

    NASA Astrophysics Data System (ADS)

    Jiang, Wen; Lai, Kuilin; Liu, Kexia; Xia, Rui; Gao, Fabao; Wu, Yao; Gu, Zhongwei

    2014-01-01

    Tea polyphenol serves as an environmentally friendly ligand-exchange molecule to synthesize multifunctional metal-doped superparamagnetic iron oxide nanoparticles via a catechol-metal coordination interaction. The resultant particles not only exhibit excellent hydrophilicity and protein adsorption resistance, but also are applicable as magnetic resonance/fluorescent dual-imaging probes due to their high T2 relaxivity, autofluorescence and large cellular uptake.Tea polyphenol serves as an environmentally friendly ligand-exchange molecule to synthesize multifunctional metal-doped superparamagnetic iron oxide nanoparticles via a catechol-metal coordination interaction. The resultant particles not only exhibit excellent hydrophilicity and protein adsorption resistance, but also are applicable as magnetic resonance/fluorescent dual-imaging probes due to their high T2 relaxivity, autofluorescence and large cellular uptake. Electronic supplementary information (ESI) available: Additional information and figures (Fig. S1-S7), including experimental sections, characterization of the products, protein corona analysis, cytotoxicity and cellular uptake quantification. See DOI: 10.1039/c3nr05003c

  16. NMR scanning of the pelvis: initial experience with a 0. 3 T system

    SciTech Connect

    Bryan, P.J.; Butler, H.E.; LiPuma, J.P.; Haaga, J.R.; El Yousef, S.J.; Resnick, M.I.; Cohen, A.M.; Malviya, V.K.; Nelson, A.D.; Clampitt, M.

    1983-12-01

    Pelvic NMR scans were obtained on 29 patients using a 0.3 T superconducting magnet system. Pathologies studied included four bladder carcinomas, four prostatic carcinomas, four ovarian dermoid cysts, three ovarian cysts, three endometrial carcinomas, two endometriomas, and one each of serous cystadenoma of the ovary, benign prostatic hypertrophy, pelvic hematoma, and undifferentiated sarcoma. NMR is a very promising method for characterizing pelvic masses and in staging pelvic malignancies. It can show primary tumors of the prostate, bladder, and uterus and reveals tumor extension into pelvic fat. The pelvis is particularly well suited to NMR scanning because of the abundant natural contrast provided by pelvic fat and by urine in the bladder and gas in the bowel. There is also less motion blurring than in the upper abdomen and chest because there is relatively little respiratory motion of pelvic organs. Various pulse sequences were used in scanning the pelvis; their relative merits are discussed.

  17. Template nanowires for spintronics applications: nanomagnet microwave resonators functioning in zero applied magnetic field.

    PubMed

    Mourachkine, A; Yazyev, O V; Ducati, C; Ansermet, J-Ph

    2008-11-01

    Low-cost spintronic devices functioning in zero applied magnetic field are required for bringing the idea of spin-based electronics into the real-world industrial applications. Here we present first microwave measurements performed on nanomagnet devices fabricated by electrodeposition inside porous membranes. In the paper, we discuss in details a microwave resonator consisting of three nanomagnets, which functions in zero external magnetic field. By applying a microwave signal at a particular frequency, the magnetization of the middle nanomagnet experiences the ferromagnetic resonance (FMR), and the device outputs a measurable direct current (spin-torque diode effect). Alternatively, the nanodevice can be used as a microwave oscillator functioning in zero field. To test the resonators at microwave frequencies, we developed a simple measurement setup.

  18. Mapping Dopamine Function in Primates Using Pharmacologic Magnetic Resonance Imaging

    PubMed Central

    Sanchez-Pernaute, Rosario; Brownell, Anna-Liisa; Chen, Yin-Ching Iris; Isacson, Ole

    2008-01-01

    Dopamine (DA) receptors play a central role in such diverse pathologies as Parkinson's disease, schizophrenia, and drug abuse. We used an amphetamine challenge combined with pharmacologic magnetic resonance imaging (phMRI) to map DA-associated circuitry in nonhuman primates with high sensitivity and spatial resolution. Seven control cynomolgous monkeys and 10 MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-treated parkinsonian primates were studied longitudinally using both positron emission tomography (PET) and phMRI. Amphetamine challenge (2.5 mg/kg, i.v.) in control monkeys increased relative cerebral blood volume (rCBV) in a number of brain regions not described previously, such as parafascicular thalamus, precentral gyrus, and dentate nucleus of the cerebellum. With the high spatial resolution, we were also able to readily identify changes in rCBV in the anterior cingulate, substantia nigra, ventral tegmental area, caudate (tail and head), putamen, and nucleus accumbens. Amphetamine induced decreases in rCBV in occipital and posterior parietal cortices. Parkinsonian primates had a prominent loss of response to amphetamine, with relative sparing of the nucleus accumbens and parafascicular thalamus. There was a significant correlation between rCBV loss in the substantia nigra and both PET imaging of dopamine transporters and behavioral measures. Monkeys with partial lesions as defined by 2β-carbomethoxy-3β-(4-fluorophenyl) tropane binding to dopamine transporters showed recruitment of premotor and motor cortex after amphetamine stimulus similar to what has been noted in Parkinson's patients during motor tasks. These data indicate that phMRI is a powerful tool for assessment of dynamic changes associated with normal and dysfunctional DA brain circuitry in primates. PMID:15509742

  19. [Functional magnetic resonance imaging for cortical mapping in epilepsy].

    PubMed

    Lajos, Rudolf Kozák; Tóth, Vivien; Barsi, Péter; Rudas, Gábor

    2011-09-30

    It is not only the total curative resection of pathological tissue or the minimization of symptoms to be considered in epilepsy surgery or other neurosurgical procedures, it is equally desirable to maintain the best possible quality of life. Cortical mapping methods can help achieve this goal by delineating eloquent areas, i.e. brain regions that are vital for providing an acceptable quality of life, albeit not prone to compensatory reorganization. These areas include among others the Broca and Wernicke regions for speech, the primary motor, sensory and visual cortices. Functional MRI gained importance in the last decade as a non-invasive clinical cortical mapping technique. This method is capable of localizing cortical areas selectively activated by a given task condition. Thus, selecting appropriate tasks can help mapping eloquent brain regions. Using functional MRI provides information that is complementary to other mapping methods. Moreover, it can replace invasive methods such as the Wada test. Here, we explain the background of functional MRI, compare it to other clinical mapping methods, explain the intricacies of paradigm selection, and show the limitations of the technique while also pointing out alternative uses.

  20. Functional Magnetic Resonance Imaging in Abstinent MDMA Users: A Review.

    PubMed

    Garg, Aayushi; Kapoor, Saloni; Goel, Mishita; Chopra, Saurav; Chopra, Manav; Kapoor, Anirudh; McCann, Una D; Behera, Chittaranjan

    2015-01-01

    Ecstasy or 3,4-methylenedioxymethamphetamine (MDMA) is a popular drug of abuse. In the animal studies MDMA has been shown to have deleterious effects on the serotonergic neurotransmitter system. Understanding the adverse effects of MDMA on human brain function is of considerable importance owing to the rising number of MDMA users. Various neuroimaging studies have investigated the structural, chemical and functional differences in the brain integrity of chronic MDMA users. Various neurocognitive domains like working memory, episodic memory, semantic memory, visual stimulation, motor function and impulsivity have been compared between chronic MDMA users and nonusers using fMRI. The fMRI studies remain much more sensitive in studying the neurological deficits associated with chronic MDMA use as compared to the cognitive studies alone and therefore they serve as a prelude in our understanding of MDMA induced neurotoxicity. However they still face certain limitations contributing to inconsistency in the results and further research is needed before we can draw definitive conclusions regarding the neurotoxic effects of MDMA.

  1. Structural and magnetic properties of turmeric functionalized CoFe2O4 nanocomposite powder

    NASA Astrophysics Data System (ADS)

    Mehran, E.; Farjami Shayesteh, S.; Sheykhan, M.

    2016-10-01

    The structural and magnetic properties of the synthesized pure and functionalized CoFe2O4 magnetic nanoparticles (NPs) are studied by analyzing the results from the x-ray diffraction (XRD), transmission electron microscopy (TEM), FT-IR spectroscopy, thermogravimetry (TG), and vibrating sample magnetometer (VSM). To extract the structure and lattice parameters from the XRD analysis results, we first apply the pseudo-Voigt model function to the experimental data obtained from XRD analysis and then the Rietveld algorithm is used in order to optimize the model function to estimate the true intensity values. Our simulated intensities are in good agreement with the experimental peaks, therefore, all structural parameters such as crystallite size and lattice constant are achieved through this simulation. Magnetic analysis reveals that the synthesized functionalized NPs have a saturation magnetization almost equal to that of pure nanoparticles (PNPs). It is also found that the presence of the turmeric causes a small reduction in coercivity of the functionalized NPs in comparison with PNP. Our TGA and FTIR results show that the turmeric is bonded very well to the surface of the NPs. So it can be inferred that a nancomposite (NC) powder of turmeric and nanoparticles is produced. As an application, the anti-arsenic characteristic of turmeric makes the synthesized functionalized NPs or NC powder a good candidate for arsenic removal from polluted industrial waste water. Project supported by the University of Guilan and the Iran Nanotechnology Initiative Council.

  2. Vortex fluidic entrapment of functional microalgal cells in a magnetic polymer matrix

    NASA Astrophysics Data System (ADS)

    Eroglu, Ela; D'Alonzo, Nicholas J.; Smith, Steven M.; Raston, Colin L.

    2013-03-01

    Composite materials based on superparamagnetic magnetite nanoparticles embedded in polyvinylpyrrolidone (PVP) are generated in a continuous flow vortex fluidic device (VFD). The same device is effective in entrapping microalgal cells within this material, such that the functional cells can be retrieved from aqueous dispersions using an external magnet.Composite materials based on superparamagnetic magnetite nanoparticles embedded in polyvinylpyrrolidone (PVP) are generated in a continuous flow vortex fluidic device (VFD). The same device is effective in entrapping microalgal cells within this material, such that the functional cells can be retrieved from aqueous dispersions using an external magnet. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr33813d

  3. Making Sense of Real-Time Functional Magnetic Resonance Imaging (rtfMRI) and rtfMRI Neurofeedback

    PubMed Central

    2015-01-01

    This review explains the mechanism of functional magnetic resonance imaging in general and specifically introduces real-time functional magnetic resonance imaging as a method for training self-regulation of brain activity. Using real-time functional magnetic resonance imaging neurofeedback, participants can acquire control over their own brain activity. In patients with neuropsychiatric disorders, this control can potentially have therapeutic implications. In this review, the technical requirements are presented and potential applications and limitations are discussed. PMID:25716778

  4. Making sense of real-time functional magnetic resonance imaging (rtfMRI) and rtfMRI neurofeedback.

    PubMed

    Brühl, Annette B

    2015-02-25

    This review explains the mechanism of functional magnetic resonance imaging in general and specifically introduces real-time functional magnetic resonance imaging as a method for training self-regulation of brain activity. Using real-time functional magnetic resonance imaging neurofeedback, participants can acquire control over their own brain activity. In patients with neuropsychiatric disorders, this control can potentially have therapeutic implications. In this review, the technical requirements are presented and potential applications and limitations are discussed.

  5. Interfacial adsorption and surfactant release characteristics of magnetically functionalized halloysite nanotubes for responsive emulsions.

    PubMed

    Owoseni, Olasehinde; Nyankson, Emmanuel; Zhang, Yueheng; Adams, Daniel J; He, Jibao; Spinu, Leonard; McPherson, Gary L; Bose, Arijit; Gupta, Ram B; John, Vijay T

    2016-02-01

    Magnetically responsive oil-in-water emulsions are effectively stabilized by a halloysite nanotube supported superparamagnetic iron oxide nanoparticle system. The attachment of the magnetically functionalized halloysite nanotubes at the oil-water interface imparts magnetic responsiveness to the emulsion and provides a steric barrier to droplet coalescence leading to emulsions that are stabilized for extended periods. Interfacial structure characterization by cryogenic scanning electron microscopy reveals that the nanotubes attach at the oil-water interface in a side on-orientation. The tubular structure of the nanotubes is exploited for the encapsulation and release of surfactant species that are typical of oil spill dispersants such as dioctyl sulfosuccinate sodium salt and polyoxyethylene (20) sorbitan monooleate. The magnetically responsive halloysite nanotubes anchor to the oil-water interface stabilizing the interface and releasing the surfactants resulting in reduction in the oil-water interfacial tension. The synergistic adsorption of the nanotubes and the released surfactants at the oil-water interface results in oil emulsification into very small droplets (less than 20μm). The synergy of the unique nanotubular morphology and interfacial activity of halloysite with the magnetic properties of iron oxide nanoparticles has potential applications in oil spill dispersion, magnetic mobilization and detection using magnetic fields. PMID:26555959

  6. Surface functionalization for tailoring the aggregation and magnetic behaviour of silica-coated iron oxide nanostructures

    NASA Astrophysics Data System (ADS)

    Roca, A. G.; Carmona, D.; Miguel-Sancho, N.; Bomatí-Miguel, O.; Balas, F.; Piquer, C.; Santamaría, J.

    2012-04-01

    We report here a detailed structural and magnetic study of different silica nanocapsules containing uniform and highly crystalline maghemite nanoparticles. The magnetic phase consists of 5 nm triethylene glycol (TREG)- or dimercaptosuccinic acid (DMSA)-coated maghemite particles. TREG-coated nanoparticles were synthesized by thermal decomposition. In a second step, TREG ligands were exchanged by DMSA. After the ligand exchange, the ζ potential of the particles changed from - 10 to - 40 mV, whereas the hydrodynamic size remained constant at around 15 nm. Particles coated by TREG and DMSA were encapsulated in silica following a sol-gel procedure. The encapsulation of TREG-coated nanoparticles led to large magnetic aggregates, which were embedded in coalesced silica structures. However, DMSA-coated nanoparticles led to small magnetic clusters inserted in silica spheres of around 100 nm. The final nanostructures can be described as the result of several competing factors at play. Magnetic measurements indicate that in the TREG-coated nanoparticles the interparticle magnetic interaction scenario has not dramatically changed after the silica encapsulation, whereas in the DMSA-coated nanoparticles, the magnetic interactions were screened due to the function of the silica template. Moreover, the analysis of the AC susceptibility suggests that our systems essentially behave as cluster spin glass systems.

  7. Molecular analysis of magnetotactic bacteria and development of functional bacterial magnetic particles for nano-biotechnology.

    PubMed

    Matsunaga, Tadashi; Suzuki, Takeyuki; Tanaka, Masayoshi; Arakaki, Atsushi

    2007-04-01

    Biomineralization is an elaborate process that produces complex nano-structures consisting of organic and inorganic components of uniform size and highly ordered morphology that self-assemble into structures in a hierarchical manner. Magnetotactic bacteria synthesize nano-sized magnetite crystals that are highly consistent in size and morphology within bacterial species; each particle is surrounded by a thin organic membrane, which facilitates their use for various biotechnological applications. Recent molecular studies, including mutagenesis, whole genome, transcriptome and comprehensive proteome analyses, have elucidated the processes important to bacterial magnetite formation. Some of the genes and proteins identified from these studies have enabled us, through genetic engineering, to express proteins efficiently, with their activity preserved, onto bacterial magnetic particles, leading to the simple preparation of functional protein-magnetic particle complexes. This review describes the recent advances in the fundamental analysis of bacterial magnetic particles and the development of surface-protein-modified magnetic particles for biotechnological applications.

  8. Stability of a pinned magnetic domain wall as a function of its internal configuration

    NASA Astrophysics Data System (ADS)

    Montaigne, F.; Duluard, A.; Briones, J.; Lacour, D.; Hehn, M.; Childress, J. R.

    2015-01-01

    It is shown that there are many stable configurations for a domain wall pinned by a notch along a magnetic stripe. The stability of several of these configurations is investigated numerically as a function of the thickness of the magnetic film. The depinning mechanism depends on the structure of the domain wall and on the thickness of the magnetic film. In the case of a spin-valve structure, it appears that the stray fields emerging from the hard layer at the notch location influence the stability of the micromagnetic configuration. Different depinning mechanisms are thus observed for the same film thickness depending on the magnetization orientation of the propagating domain. This conclusion qualitatively explains experimental magnetoresistance measurements.

  9. Ionic-liquid-functionalized magnetic particles as an adsorbent for the magnetic SPE of sulfonylurea herbicides in environmental water samples.

    PubMed

    He, Zeying; Liu, Donghui; Zhou, Zhiqiang; Wang, Peng

    2013-10-01

    In this paper, a new ionic-liquid-functionalized magnetic material was prepared based on the immobilization of an ionic liquid on silica magnetic particles that could be successfully used as an adsorbent for the magnetic SPE of five sulfonylurea herbicides (bensulfuron-methyl, prosulfuron, pyrazosulfuron-ethyl, chlorimuron-ethyl and triflusulfuron-methyl) from environmental water samples. The main parameters affecting the extraction efficiency such as desorption conditions, sample pH, extraction time and so on, were optimized using the Taguchi method. Good linearities were obtained with correlation coefficients ranging from 0.9992 to 0.9999 in the concentration range of 0.1-50 μg L(-1) and the LODs were 0.053-0.091 μg L(-1). Under the optimum conditions, the enrichment factors of the method were 1155-1380 and the recoveries ranged from 77.8 to 104.4%. The proposed method was reliable and could be applied to the residue analysis of sulfonylurea herbicides in environmental water samples (tap, reservoir and river).

  10. A facile fabrication of spherical and beanpod-like magnetic-fluorescent particles with targeting functionalities

    NASA Astrophysics Data System (ADS)

    Liu, Yan-Lin; Zhang, Ji-Lin; Cheng, Gong; Hong, Guang-Yan; Ni, Jia-Zuan

    2012-10-01

    Magnetic-fluorescent particles with targeting functionalities were fabricated by a modified Stöber method and two shapes (spherical and beanpod-like) were obtained by simply tuning the reaction temperature. The two multifunctional probes combined the useful functions of magnetism, fluorescence and FA (folic acid)-targeting recognition into one entity. The products were characterized by scanning electron microscopy, transmission electron microscopy, photoluminescence spectroscopy, confocal laser scanning microscopy, by a superconducting quantum interference device and by Fourier transform infrared spectroscopy. The experimental results show that the products possessed rapid magnetic response, relatively strong fluorescent signal, higher photostability and FA-targeting recognition as well as good water-dispersibility, suggesting that they would have potential medical applications in biolabeling and bioimaging.

  11. A Functional Magnetic Resonance Imaging Investigation of Verbal Working Memory in Adolescents with Specific Language Impairment

    ERIC Educational Resources Information Center

    Weismer, Susan Ellis; Plante, Elena; Jones, Maura; Tomblin, Bruce J.

    2005-01-01

    This study used neuroimaging and behavioral techniques to examine the claim that processing capacity limitations underlie specific language impairment (SLI). Functional magnetic resonance imaging (fMRI) was used to investigate verbal working memory in adolescents with SLI and normal language (NL) controls. The experimental task involved a modified…

  12. Functional Magnetic Resonance Imaging of Cognitive Processing in Young Adults with Down Syndrome

    ERIC Educational Resources Information Center

    Jacola, Lisa M.; Byars, Anna W.; Chalfonte-Evans, Melinda; Schmithorst, Vincent J.; Hickey, Fran; Patterson, Bonnie; Hotze, Stephanie; Vannest, Jennifer; Chiu, Chung-Yiu; Holland, Scott K.; Schapiro, Mark B.

    2011-01-01

    The authors used functional magnetic resonance imaging (fMRI) to investigate neural activation during a semantic-classification/object-recognition task in 13 persons with Down syndrome and 12 typically developing control participants (age range = 12-26 years). A comparison between groups suggested atypical patterns of brain activation for the…

  13. Modelling of heat assisted magnetic recording with the Landau-Lifshitz-Bloch equation and Brillouin functions

    NASA Astrophysics Data System (ADS)

    Greaves, Simon John; Muraoka, Hiroaki; Kanai, Yasushi

    2015-05-01

    Brillouin functions were used to model the temperature dependence of magnetisation in media for heat assisted magnetic recording. Although dHk/dT was higher when Brillouin functions with J = 0.5 or J = 1 were used, an earlier onset of the linear reversal mode led to a drop in dHc/dT near to Tc, resulting in wider written bits. Tracks written with a higher thermal gradient were also wider when J was small and had lower SNR.

  14. Hyperpolarized functional magnetic resonance of murine skeletal muscle enabled by multiple tracer-paradigm synchronizations.

    PubMed

    Leftin, Avigdor; Roussel, Tangi; Frydman, Lucio

    2014-01-01

    Measuring metabolism's time- and space-dependent responses upon stimulation lies at the core of functional magnetic resonance imaging. While focusing on water's sole resonance, further insight could arise from monitoring the temporal responses arising from the metabolites themselves, in what is known as functional magnetic resonance spectroscopy. Performing these measurements in real time, however, is severely challenged by the short functional timescales and low concentrations of natural metabolites. Dissolution dynamic nuclear polarization is an emerging technique that can potentially alleviate this, as it provides a massive sensitivity enhancement allowing one to probe low-concentration tracers and products in a single-scan. Still, conventional implementations of this hyperpolarization approach are not immediately amenable to the repeated acquisitions needed in real-time functional settings. This work proposes a strategy for functional magnetic resonance of hyperpolarized metabolites that bypasses this limitation, and enables the observation of real-time metabolic changes through the synchronization of stimuli-triggered, multiple-bolus injections of the metabolic tracer 13C1-pyruvate. This new approach is demonstrated with paradigms tailored to reveal in vivo thresholds of murine hind-limb skeletal muscle activation, involving the conversion of 13C1-pyruvate to 13C1-lactate and 13C1-alanine. These functional hind-limb studies revealed that graded skeletal muscle stimulation causes commensurate increases in glycolytic metabolism in a frequency- and amplitude-dependent fashion, that can be monitored on the seconds/minutes timescale using dissolution dynamic nuclear polarization. Spectroscopic imaging further allowed the in vivo visualization of uptake, transformation and distribution of the tracer and products, in fast-twitch glycolytic and in slow-twitch oxidative muscle fiber groups. While these studies open vistas in time and sensitivity for metabolic

  15. Hyperpolarized Functional Magnetic Resonance of Murine Skeletal Muscle Enabled by Multiple Tracer-Paradigm Synchronizations

    PubMed Central

    Leftin, Avigdor; Roussel, Tangi; Frydman, Lucio

    2014-01-01

    Measuring metabolism's time- and space-dependent responses upon stimulation lies at the core of functional magnetic resonance imaging. While focusing on water's sole resonance, further insight could arise from monitoring the temporal responses arising from the metabolites themselves, in what is known as functional magnetic resonance spectroscopy. Performing these measurements in real time, however, is severely challenged by the short functional timescales and low concentrations of natural metabolites. Dissolution dynamic nuclear polarization is an emerging technique that can potentially alleviate this, as it provides a massive sensitivity enhancement allowing one to probe low-concentration tracers and products in a single-scan. Still, conventional implementations of this hyperpolarization approach are not immediately amenable to the repeated acquisitions needed in real-time functional settings. This work proposes a strategy for functional magnetic resonance of hyperpolarized metabolites that bypasses this limitation, and enables the observation of real-time metabolic changes through the synchronization of stimuli-triggered, multiple-bolus injections of the metabolic tracer 13C1-pyruvate. This new approach is demonstrated with paradigms tailored to reveal in vivo thresholds of murine hind-limb skeletal muscle activation, involving the conversion of 13C1-pyruvate to 13C1-lactate and 13C1-alanine. These functional hind-limb studies revealed that graded skeletal muscle stimulation causes commensurate increases in glycolytic metabolism in a frequency- and amplitude-dependent fashion, that can be monitored on the seconds/minutes timescale using dissolution dynamic nuclear polarization. Spectroscopic imaging further allowed the in vivo visualization of uptake, transformation and distribution of the tracer and products, in fast-twitch glycolytic and in slow-twitch oxidative muscle fiber groups. While these studies open vistas in time and sensitivity for metabolic

  16. Operant-contingency-based preparation of children for functional magnetic resonance imaging.

    PubMed

    Slifer, Keith J; Koontz, Kristine L; Cataldo, Michael F

    2002-01-01

    Functional magnetic resonance imaging (fMRI) is used to study brain function during behavioral tasks. The participation of pediatric subjects is problematic because reliable task performance and control of head movement are simultaneously required. Differential reinforcement decreased head motion and improved vigilance task performance in 4 children (2 with behavioral disorders) undergoing simulated fMRI scans. Results show that behavior analysis techniques can improve child cooperation during fMRI procedures.

  17. Evaluation of chylomicron effect on ASP production in 3T3-L1 adipocytes.

    PubMed

    Gao, Ying; Gauvreau, Danny; Cui, Wei; Lapointe, Marc; Paglialunga, Sabina; Cianflone, Katherine

    2011-02-01

    In the past few years, there has been increasing interest in the production and physiological role of acylation-stimulating protein (ASP), identical to C3adesArg, a product of the alternative complement pathway generated through C3 cleavage. Recent studies in C3 (-/-) mice that are ASP deficient have demonstrated a role for ASP in postprandial triglyceride clearance and fat storage. The aim of the present study was to establish a cell model and sensitive ELISA assay for the evaluation of ASP production using 3T3-L1 adipocytes. 3T3-L1 preadipocytes were differentiated into adipocytes, then cultured in different media such as serum-free (SF), Dulbecco's modified Eagle's medium (DMEM)/F12 + 10% fetal calf serum (FBS), and at varying concentrations of chylomicrons and insulin + chylomicrons up to 48 h. ASP production in SF and DMEM/F12 + 10% FBS was compared. Chylomicrons stimulated ASP production in a concentration- and time-dependent manner. By contrast, chylomicron treatment had no effect on the production of C3, the precursor protein of ASP, which was constant over 48 h. Addition of insulin (100 nM) to a low-dose of chylomicrons (100 µg TG/ml) significantly increased ASP production compared with chylomicrons alone at 48 h (P < 0.001). Furthermore, addition of insulin significantly increased C3 secretion at both 18 and 48 h of incubation (P < 0.05, P < 0.001, respectively). Overall, the proportion of ASP to C3 remained constant, indicating no change in the ratio of C3 cleaved to generate ASP. This study demonstrated that 3T3-L1 adipocyte is a useful model for the evaluation of C3 secretion and ASP production by using a sensitive mouse-specific ELISA assay. The stimulation of ASP production with chylomicrons demonstrates a physiologically relevant response, and provides a strategy for further studies on ASP production and function.

  18. Lysophosphatidic acid induces chemotaxis in MC3T3-E1 osteoblastic cells

    SciTech Connect

    Masiello, Lisa M.; Fotos, Joseph S.; Galileo, Deni S.; Karin, Norm J.

    2006-07-01

    Lysophosphatidic acid (LPA) is a bioactive lipid that has pleiotropic effects on a variety of cell types and enhances the migration of endothelial and cancer cells, but it is not known if this lipid can alter osteoblast motility. We performed transwell migration assays using MC3T3-E1 osteoblastic cells and found LPA to be a potent chemotactic agent. Quantitative time-lapse video analysis of osteoblast migration after wounds were introduced into cell monolayers indicated that LPA stimulated both migration velocity and the average migration distance per cell. LPA also elicited substantial changes in cell shape and actin cytoskeletal structure; lipid-treated cells contained fewer stress fibers and displayed long membrane processes that were enriched in F-actin. Quantitative RT-PCR analysis showed that MC3T3-E1 cells express all four known LPA-specific G protein-coupled receptors (LPA1-LPA4) with a relative mRNA abundance of LPA1 > LPA4 > LPA2 >> LPA3. LPA-induced changes in osteoblast motility and morphology were antagonized by both pertussis toxin and Ki16425, a subtype-specific blocker of LPA1 and LPA3 receptor function. Cell migration in many cell types is linked to changes in intracellular Ca2+. Ki16425 also inhibited LPA-induced Ca2+ signaling in a dose-dependent manner, suggesting a link between LPA-induced Ca2+ transients and osteoblast chemotaxis. Our data show that LPA stimulates MC3T3-E1 osteoblast motility via a mechanism that is linked primarily to the G protein-coupled receptor LPA1.

  19. 26 CFR 1.6050H-3T - Information reporting of mortgage insurance premiums (temporary).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... premiums (temporary). 1.6050H-3T Section 1.6050H-3T Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT....6050H-3T Information reporting of mortgage insurance premiums (temporary). (a) Information reporting... (or their successor organizations), or to private mortgage insurance (as defined by section 2 of...

  20. 26 CFR 1.6050H-3T - Information reporting of mortgage insurance premiums (temporary).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... premiums (temporary). 1.6050H-3T Section 1.6050H-3T Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT....6050H-3T Information reporting of mortgage insurance premiums (temporary). (a) Information reporting... (or their successor organizations), or to private mortgage insurance (as defined by section 2 of...

  1. 26 CFR 1.410(a)-3T - Minimum age and service conditions (temporary).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 5 2011-04-01 2011-04-01 false Minimum age and service conditions (temporary). 1.410(a)-3T Section 1.410(a)-3T Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE... Plans, Etc. § 1.410(a)-3T Minimum age and service conditions (temporary). (a) (b) Special rule for...

  2. 26 CFR 1.410(a)-3T - Minimum age and service conditions (temporary).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 5 2010-04-01 2010-04-01 false Minimum age and service conditions (temporary). 1.410(a)-3T Section 1.410(a)-3T Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE.... § 1.410(a)-3T Minimum age and service conditions (temporary). (a) (b) Special rule for plan with...

  3. 26 CFR 1.410(a)-3T - Minimum age and service conditions (temporary).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 5 2014-04-01 2014-04-01 false Minimum age and service conditions (temporary). 1.410(a)-3T Section 1.410(a)-3T Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE... Plans, Etc. § 1.410(a)-3T Minimum age and service conditions (temporary). (a) (b) Special rule for...

  4. 26 CFR 1.410(a)-3T - Minimum age and service conditions (temporary).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 5 2012-04-01 2011-04-01 true Minimum age and service conditions (temporary). 1.410(a)-3T Section 1.410(a)-3T Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY.... § 1.410(a)-3T Minimum age and service conditions (temporary). (a) (b) Special rule for plan with...

  5. 26 CFR 1.103(n)-3T - Private activity bond limit (temporary).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 2 2011-04-01 2011-04-01 false Private activity bond limit (temporary). 1.103(n)-3T Section 1.103(n)-3T Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY....103(n)-3T Private activity bond limit (temporary). Q-1: What is the “State ceiling”? A-1: In...

  6. Stationary electron velocity distribution function in crossed electric and magnetic fields with collisions

    SciTech Connect

    Shagayda, Andrey

    2012-08-15

    Analytical studies and numerical simulations show that the electron velocity distribution function in a Hall thruster discharge with crossed electric and magnetic fields is not Maxwellian. This is due to the fact that the mean free path between collisions is greater than both the Larmor radius and the characteristic dimensions of the discharge channel. However in numerical models of Hall thrusters, a hydrodynamic approach is often used to describe the electron dynamics, because discharge simulation in a fully kinetic approach requires large computing resources and is time consuming. A more accurate modeling of the electron flow in the hydrodynamic approximation requires taking into account the non-Maxwellian character of the distribution function and finding its moments, an approach that reflects the properties of electrons drifting in crossed electric and magnetic fields better than the commonly used Euler or Navier-Stokes approximations. In the present paper, an expression for the electron velocity distribution function in rarefied spatially homogeneous stationary plasma with crossed electric and magnetic fields and predominance of collisions with heavy particles is derived in the relaxation approximation. The main moments of the distribution function including longitudinal and transversal temperatures, the components of the viscous stress tensor, and of the heat flux vector are calculated. Distinctive features of the hydrodynamic description of electrons with a strongly non-equilibrium distribution function and the prospects for further development of the proposed approach for calculating the distribution function in spatially inhomogeneous plasma are discussed.

  7. SUPERCONDUCTING COMBINED FUNCTION MAGNET SYSTEM FOR J-PARC NEUTRINO EXPERIMENT.

    SciTech Connect

    OGITSU, T.; AJIMA, Y.; ANERELLA, M.; ESCALLIER, J.; GANETIS, G.; GUPTA, R.; HAGEDOM, D.; HARRISON, M.; HIGASHI, N.; IWAMOTO, Y.; ICHIKAWA, A.; JAIN, A.; KIMURA, N.; KOBAYASHI, T.; MAKIDA, Y.; MURATORE, J.; NAKAMOTO, T.; OHHATA, H.; TAKASAKI, N.; TANAKA, K.; TERASHIMA, A.; YAMOMOTO, A.; OBANA, T.; PARKER, B.; WANDERER, P.

    2004-10-03

    The J-PARC Neutrino Experiment, the construction of which starts in JFY 2004, will use a superconducting magnet system for its primary proton beam line. The system, which bends the 50 GeV 0.75 MW proton beam by about 80 degrees, consists of 28 superconducting combined function magnets. The magnets utilize single layer left/right asymmetric coils that generate a dipole field of 2.6 T and a quadrupole field of 18.6 T/m with the operation current of about 7.35 kA. The system also contains a few conduction cooled superconducting corrector magnets that serve as vertical and horizontal steering magnets. All the magnets are designed to provide a physical beam aperture of 130 mm in order to achieve a large beam acceptance. Extensive care is also required to achieve safe operation with the high power proton beam. The paper summarizes the system design as well as some safety analysis results.

  8. Investigation of the Magnetic Behavior in Fe3O4 Ferrofluid Functionalized by Carapa Guianensis Oil

    NASA Astrophysics Data System (ADS)

    López, Jorge Luis; Rodriguez, Anselmo Fortunato Ruiz; de Jesus Nascimento Pontes, Maria; de Morais, Paulo Cesar; de Azevedo, Ricardo Bentes; Pfannes, Hans Dieter; Dias Filho, José Higino

    2010-12-01

    A ferrofluid based on Fe3O4 has been synthesized using the condensation method by coprecipitating aqueous solutions of FeSO4 and FeCl3 mixtures in NH4OH and treated further in order to obtain colloidal sols by creating a charge density on their surface and functionalized by carapa guianensis (andiroba oil). Aqueous sample with an average particle diameter ˜7 nm were studied by Mössbauer spectroscopy and dc magnetization measurements in the range of 4.2-250 K. The saturation magnetization (Ms) at 4.2 K was determined from M vs 1/H plots by extrapolating the value of magnetizations to infinite fields, to 5.6 emu/g and coercivity to 344 Oe. The low saturation magnetization value was attributed to spin noncollinearity predominantly at the surface. From the magnetization measurements a magnetic anisotropy energy constant (K) of 1×104 J/m3 was calculated. Fe3O4 spectra at room temperature showed a singlet due to superparamagnetic relaxation and a sextet at low temperature.

  9. Spectral functions in a magnetic field as a probe of spin-charge separation

    NASA Astrophysics Data System (ADS)

    Rabello, Silvio; Si, Qimiao

    2001-03-01

    We show that the single-particle spectral functions in a magnetic field can be used to probe spin-charge separation[1]. For concreteness our discussion will be focused on the Luttinger liquid, but our idea is applicable to spin-charge separated metals in general. We will show two types of manifestations of spin-charge separation. For the energy dispersion away from the Fermi momentum, the magnetic field splits both the spinon peak and holon peak; here the spin-charge separation nature is reflected in the different magnitude of the two splittings. For the energy dispersion at the Fermi momentum, the magnetic field splits the zero-field peak into FOUR peaks. The effect of a magnetic field on the momentum dispersion, on the other hand, is very different. Either at or away from the Fermi energy, the magnetic field splits the zero-field peak into only two peaks; the magnitude of the splittings of the spinon and holon peaks is always the same. The contrast between the energy dispersion and momentum dispersion reflects the generic physics that the magnetic field causes as main effect the splitting of the spinon Fermi momentum. Finally, we will discuss the feasibility of studying this effect using angle-resolved photoemission and momentum-resolved tunneling[2]. [1] S. Rabello and Q. Si, cond-mat/0008065. [2]S. A. Grigera, S. Rabello et al, in preparation; A. Altland et al. Phys. Rev. Lett. 83, 1203 (1999).

  10. Magnetic assembly of transparent and conducting graphene-based functional composites

    PubMed Central

    Le Ferrand, Hortense; Bolisetty, Sreenath; Demirörs, Ahmet F.; Libanori, Rafael; Studart, André R.; Mezzenga, Raffaele

    2016-01-01

    Innovative methods producing transparent and flexible electrodes are highly sought in modern optoelectronic applications to replace metal oxides, but available solutions suffer from drawbacks such as brittleness, unaffordability and inadequate processability. Here we propose a general, simple strategy to produce hierarchical composites of functionalized graphene in polymeric matrices, exhibiting transparency and electron conductivity. These are obtained through protein-assisted functionalization of graphene with magnetic nanoparticles, followed by magnetic-directed assembly of the graphene within polymeric matrices undergoing sol–gel transitions. By applying rotating magnetic fields or magnetic moulds, both graphene orientation and distribution can be controlled within the composite. Importantly, by using magnetic virtual moulds of predefined meshes, graphene assembly is directed into double-percolating networks, reducing the percolation threshold and enabling combined optical transparency and electrical conductivity not accessible in single-network materials. The resulting composites open new possibilities on the quest of transparent electrodes for photovoltaics, organic light-emitting diodes and stretchable optoelectronic devices. PMID:27354243

  11. A multi-functional testing instrument for heat assisted magnetic recording media

    SciTech Connect

    Yang, H. Z. Chen, Y. J.; Leong, S. H.; An, C. W.; Ye, K. D.; Hu, J. F.; Yin, M. J.

    2014-05-07

    With recent developments in heat assisted magnetic recording (HAMR), characterization of HAMR media is becoming very important. We present a multi-functional instrument for testing HAMR media, which integrates HAMR writing, reading, and a micro-magneto-optic Kerr effect (μ-MOKE) testing function. A potential application of the present instrument is to make temperature dependent magnetic property measurement using a pump-probe configuration. In the measurement, the media is heated up by a heating (intense) beam while a testing (weak) beam is overlapped with the heating beam for MOKE measurement. By heating the media with different heating beam power, magnetic measurements by MOKE at different temperatures can be performed. Compared to traditional existing tools such as the vibrating sample magnetometer, the present instrument provides localized and efficient heating at the measurement spot. The integration of HAMR writing and μ-MOKE system can also facilitate a localized full investigation of the magnetic media by potential correlation of HAMR head independent write/read performance to localized magnetic properties.

  12. Phonon and magnetic structure in δ-plutonium from density-functional theory

    DOE PAGES

    Söderlind, Per; Zhou, F.; Landa, A.; Klepeis, J. E.

    2015-10-30

    We present phonon properties of plutonium metal obtained from a combination of density-functional-theory (DFT) electronic structure and the recently developed compressive sensing lattice dynamics (CSLD). The CSLD model is here trained on DFT total energies of several hundreds of quasi-random atomic configurations for best possible accuracy of the phonon properties. The calculated phonon dispersions compare better with experiment than earlier results obtained from dynamical mean-field theory. The density-functional model of the electronic structure consists of disordered magnetic moments with all relativistic effects and explicit orbital-orbital correlations. The magnetic disorder is approximated in two ways: (i) a special quasi-random structure andmore » (ii) the disordered-local-moment (DLM) method within the coherent potential approximation. Magnetism in plutonium has been debated intensely, However, the present magnetic approach for plutonium is validated by the close agreement between the predicted magnetic form factor and that of recent neutron-scattering experiments.« less

  13. Magnetic assembly of transparent and conducting graphene-based functional composites.

    PubMed

    Le Ferrand, Hortense; Bolisetty, Sreenath; Demirörs, Ahmet F; Libanori, Rafael; Studart, André R; Mezzenga, Raffaele

    2016-01-01

    Innovative methods producing transparent and flexible electrodes are highly sought in modern optoelectronic applications to replace metal oxides, but available solutions suffer from drawbacks such as brittleness, unaffordability and inadequate processability. Here we propose a general, simple strategy to produce hierarchical composites of functionalized graphene in polymeric matrices, exhibiting transparency and electron conductivity. These are obtained through protein-assisted functionalization of graphene with magnetic nanoparticles, followed by magnetic-directed assembly of the graphene within polymeric matrices undergoing sol-gel transitions. By applying rotating magnetic fields or magnetic moulds, both graphene orientation and distribution can be controlled within the composite. Importantly, by using magnetic virtual moulds of predefined meshes, graphene assembly is directed into double-percolating networks, reducing the percolation threshold and enabling combined optical transparency and electrical conductivity not accessible in single-network materials. The resulting composites open new possibilities on the quest of transparent electrodes for photovoltaics, organic light-emitting diodes and stretchable optoelectronic devices. PMID:27354243

  14. Development of Small-sized Fluid Control Valve with Self-holding Function Using Permanent Magnet

    NASA Astrophysics Data System (ADS)

    Akagi, Tetsuya; Dohta, Shujiro; Ueda, Hirofumi

    Recently, force feedback devices in virtual reality and power assisted nursing care systems have received much attention and active research. In such a control system, an actuator and a driving device such as a control valve are mounted on the human body. In this condition, the size and weight of the control valve become serious problems. At the same time, the valve should be operated with lower energy consumption because of using a limited electrical power. The typical electro magnetic solenoid valve drives its spool using a larger solenoid to open the valve. The complex construction of the valve for sealing makes its miniaturization and the fabrication of a low cost valve more difficult. In addition, the solenoid in the valve consumes more electrical power while the valve is kept opening. The purpose of our study is to develop a small-sized, lightweight, lower energy consumption and flexible control valve that can be safe enough to mount on the human body at a lower cost. In our pervious study, we proposed and tested the control valve that can open using a vibration motor. In this study, we propose and test a new type of fluid control valve with a self-holding function. The new valve uses a permanent magnet ball. It has a cylindrical magnet and two solenoids. The self-holding function of the valve is done as follows. When one side of the solenoid is stimulated by the current momentarily, the solenoid gives a repulsive force to the cylindrical magnet. The magnet moves toward the opposite side of the solenoid and is attracted to the iron core. Then, the magnet ball moves toward the cylindrical magnet and opens the orifice. The valve can keep open without electrical energy. As a result, the valve with the extremely lower energy consumption can be developed.

  15. Resting state functional connectivity magnetic resonance imaging integrated with intraoperative neuronavigation for functional mapping after aborted awake craniotomy

    PubMed Central

    Batra, Prag; Bandt, S. Kathleen; Leuthardt, Eric C.

    2016-01-01

    Background: Awake craniotomy is currently the gold standard for aggressive tumor resections in eloquent cortex. However, a significant subset of patients is unable to tolerate this procedure, particularly the very young or old or those with psychiatric comorbidities, cardiopulmonary comorbidities, or obesity, among other conditions. In these cases, typical alternative procedures include biopsy alone or subtotal resection, both of which are associated with diminished surgical outcomes. Case Description: Here, we report the successful use of a preoperatively obtained resting state functional connectivity magnetic resonance imaging (MRI) integrated with intraoperative neuronavigation software in order to perform functional cortical mapping in the setting of an aborted awake craniotomy due to loss of airway. Conclusion: Resting state functional connectivity MRI integrated with intraoperative neuronavigation software can provide an alternative option for functional cortical mapping in the setting of an aborted awake craniotomy. PMID:26958419

  16. Skyrmion core size dependence as a function of the perpendicular anisotropy and radius in magnetic nanodots

    NASA Astrophysics Data System (ADS)

    Castro, M. A.; Allende, S.

    2016-11-01

    A detailed analytical and numerical analysis of the skyrmion core size dependence as a function of the uniaxial perpendicular anisotropy and radius in magnetic nanodots has been carried out. Results from micromagnetic calculations show a non-monotonic behavior between the skyrmion core size and the uniaxial perpendicular anisotropy. The increment of the radius reduces the skyrmion core size at constant uniaxial perpendicular anisotropy. Thus, these results can be used for the control of the core sizes in magnetic artificial skyrmion crystals or spintronic devices that need to use a skyrmion configuration at room temperature.

  17. Green's function of the magnetic topological insulator in a gradient expansion approach

    NASA Astrophysics Data System (ADS)

    Hama, Yusuke; Nagaosa, Naoto

    2016-09-01

    We study the Keldysh Green's function of the Weyl fermion surface state of the three-dimensional topological insulator coupled with a space-time dependent magnetization in the gradient expansion. Based on this, we analyze the electric charge and current densities as well as the energy density and current induced by spatially and temporally slowly varying magnetization fields. We show that all the above quantities except the energy current are generated by the emergent electromagnetic fields. The energy current emerges as the circular current reflecting the spatial modulation of an induced gap of the Weyl fermion.

  18. Magnetic properties of cobalt single layer added on graphene: A density functional theory study

    NASA Astrophysics Data System (ADS)

    Afshar, M.; Doosti, H.

    2015-01-01

    In this paper, we have demonstrated magnetic ordering of single cobalt layer added on graphene using relativistic density functional theory at the level of generalized gradient approximation. We have shown that the single Co layer added on graphene show ferromagnetic ordering with perpendicular alignment to the graphene sheet. In the presence of spin-orbit coupling, a spin-polarization degree of about 92% was found for this quasi-two-dimensional magnetic system where it is shown a nearly half-metallic feature.

  19. Preparation and characterization of chemically functionalized silica-coated magnetic nanoparticles as a DNA separator.

    PubMed

    Kang, Kiho; Choi, Jinsub; Nam, Joong Hee; Lee, Sang Cheon; Kim, Kyung Ja; Lee, Sang-Won; Chang, Jeong Ho

    2009-01-15

    The work describes a simple and convenient process for highly efficient and direct DNA separation with functionalized silica-coated magnetic nanoparticles. Iron oxide magnetic nanoparticles and silica-coated magnetic nanoparticles were prepared uniformly, and the silica coating thickness could be easily controlled in a range from 10 to 50 nm by changing the concentration of silica precursor (TEOS) including controlled magnetic strength and particle size. A change in the surface modification on the nanoparticles was introduced by aminosilanization to enhance the selective DNA separation resulting from electrostatic interaction. The efficiency of the DNA separation was explored via the function of the amino-group numbers, particle size, the amount of the nanoparticles used, and the concentration of NaCl salt. The DNA adsorption yields were high in terms of the amount of triamino-functionalized nanoparticles used, and the average particle size was 25 nm. The adsorption efficiency of aminofunctionalized nanoparticles was the 4-5 times (80-100%) higher compared to silica-coated nanoparticles only (10-20%). DNA desorption efficiency showed an optimum level of over 0.7 M of the NaCl concentration. To elucidate the agglomeration of nanoparticles after electrostatic DNA binding, the Guinier plots were calculated from small-angle X-ray diffractions in a comparison of the results of energy diffraction TEM and confocal laser scanning microscopy. Additionally, the direct separation of human genomic DNA was achieved from human saliva and whole blood with high efficiency.

  20. Fabrication and hyperthermia effect of magnetic functional fluids based on amorphous particles

    NASA Astrophysics Data System (ADS)

    Yang, Chuncheng; Bian, Xiufang; Qin, Jingyu; Guo, Tongxiao; Zhao, Shuchun

    2015-03-01

    An experimental study conducted on the preparation and hyperthermia effect of magnetic functional fluids based on Fe73.5Nb3Cu1Si13.5B9 amorphous particles, CoFe2O4 nanoparticles and Fe3O4 nanoparticles dispersed in water is presented. Scanning electron microscopy, X-ray diffraction, differential scanning calorimetry and vibrating sample magnetometer methods have been used to characterize the morphology, structure and magnetic property of the amorphous particles. It is disclosed that the Fe73.5Nb3Cu1Si13.5B9 particles are still amorphous after being milled for 48 h. Moreover, the saturation magnetization of metallic glass particles is approximately 75% and 50% larger than that of CoFe2O4 nanoparticles and Fe3O4 nanoparticles, respectively. The hyperthermia experiment results show that when alternating electrical current is 150 A, the temperature of the functional fluids based on amorphous particles could rise to 33 °C in 1500 s. When the current is 300 A, the final stable temperature could reach to 60 °C. This study demonstrates that the Fe73.5Nb3Cu1Si13.5B9 magnetic functional fluids may have potential on biomedical applications.

  1. Event-related functional magnetic resonance imaging: modelling, inference and optimization.

    PubMed Central

    Josephs, O; Henson, R N

    1999-01-01

    Event-related functional magnetic resonance imaging is a recent and popular technique for detecting haemodynamic responses to brief stimuli or events. However, the design of event-related experiments requires careful consideration of numerous issues of measurement, modelling and inference. Here we review these issues, with particular emphasis on the use of basis functions within a general linear modelling framework to model and make inferences about the haemodynamic response. With these models in mind, we then consider how the properties of functional magnetic resonance imaging data determine the optimal experimental design for a specific hypothesis, in terms of stimulus ordering and interstimulus interval. Finally, we illustrate various event-related models with examples from recent studies. PMID:10466147

  2. Iron oxide magnetic nanoparticles with versatile surface functions based on dopamine anchors

    NASA Astrophysics Data System (ADS)

    Mazur, Mykola; Barras, Alexandre; Kuncser, Victor; Galatanu, Andrei; Zaitzev, Vladimir; Turcheniuk, Kostiantyn V.; Woisel, Patrice; Lyskawa, Joel; Laure, William; Siriwardena, Aloysius; Boukherroub, Rabah; Szunerits, Sabine

    2013-03-01

    The synthesis of multifunctional magnetic nanoparticles (MF-MPs) is one of the most active research areas in advanced materials as their multifunctional surfaces allow conjugation of biological and chemical molecules, thus making it possible to achieve target-specific diagnostic in parallel to therapeutics. We report here a simple strategy to integrate in a one-step reaction several reactive sites onto the particles. The preparation of MF-MPs is based on their simultaneous modification with differently functionalized dopamine derivatives using simple solution chemistry. The formed MF-MPs show comparable magnetic properties to those of naked nanoparticles with almost unaltered particle size of around 25 nm. The different termini, amine, azide and maleimide functions, enable further functionalization of MF-MPs by the grafting-on approach. Michael addition, Cu(i) catalyzed « click » chemistry and amidation reactions are performed on the MF-MPs integrating subsequently 6-(ferrocenyl)-hexanethiol, horseradish peroxidase (HRP) and mannose.

  3. Functionalized magnetic nanowires for chemical and magneto-mechanical induction of cancer cell death

    PubMed Central

    Martínez-Banderas, Aldo Isaac; Aires, Antonio; Teran, Francisco J.; Perez, Jose Efrain; Cadenas, Jael F.; Alsharif, Nouf; Ravasi, Timothy; Cortajarena, Aitziber L.; Kosel, Jürgen

    2016-01-01

    Exploiting and combining different properties of nanomaterials is considered a potential route for next generation cancer therapies. Magnetic nanowires (NWs) have shown good biocompatibility and a high level of cellular internalization. We induced cancer cell death by combining the chemotherapeutic effect of doxorubicin (DOX)-functionalized iron NWs with the mechanical disturbance under a low frequency alternating magnetic field. (3-aminopropyl)triethoxysilane (APTES) and bovine serum albumin (BSA) were separately used for coating NWs allowing further functionalization with DOX. Internalization was assessed for both formulations by confocal reflection microscopy and inductively coupled plasma-mass spectrometry. From confocal analysis, BSA formulations demonstrated higher internalization and less agglomeration. The functionalized NWs generated a comparable cytotoxic effect in breast cancer cells in a DOX concentration-dependent manner, (~60% at the highest concentration tested) that was significantly different from the effect produced by free DOX and non-functionalized NWs formulations. A synergistic cytotoxic effect is obtained when a magnetic field (1 mT, 10 Hz) is applied to cells treated with DOX-functionalized BSA or APTES-coated NWs, (~70% at the highest concentration). In summary, a bimodal method for cancer cell destruction was developed by the conjugation of the magneto-mechanical properties of iron NWs with the effect of DOX producing better results than the individual effects. PMID:27775082

  4. Cognitive functional magnetic resonance imaging at very-high-field: eye movement control.

    PubMed

    Luna, B; Sweeney, J A

    1999-02-01

    The oculomotor system, which optimizes visual interaction with the environment, provides a valuable model system for probing the building blocks of higher-order cognition. Attention shifting, working memory, and inhibition of prepotent responses can be investigated in healthy individuals and patients with brain disorders. Although the neurophysiology of the oculomotor system has been well characterized at the single-cell level in nonhuman primates, its functional architecture in humans determined by evoked response procedures and studies of patients with focal lesions has been limited. Available evidence points to a widely distributed set of neocortical and subcortical brain regions involved in the control of eye movements, including brain stem, cerebellum, thalamus, striatum, and parietal and frontal cortices. The advent of functional magnetic resonance imaging provides a noninvasive manner of localizing, at high spatial resolution, the brain systems that subserve different aspects of sensory and cognitive processes in humans. Functional magnetic resonance imaging studies have already delineated the brain systems subserving sensorimotor and cognitive control of eye movements in adult and pediatric populations. Hence, the combination of functional magnetic resonance imaging and eye movement procedures can be used to probe the integrity of the brain in neurological and psychiatric disorders as well as provide a window into the changes in brain function subserving cognitive development. PMID:10389669

  5. Foxp3+ T cells inhibit antitumor immune memory modulated by mTOR inhibition.

    PubMed

    Wang, Yanping; Sparwasser, Tim; Figlin, Robert; Kim, Hyung L

    2014-04-15

    Inhibition of mTOR signaling enhances antitumor memory lymphocytes. However, pharmacologic mTOR inhibition also enhances regulatory T-cell (Treg) activity. To counter this effect, Treg control was added to mTOR inhibition in preclinical models. Tregs were controlled with CD4-depleting antibodies because CD4 depletion has high translational potential and already has a well-established safety profile in patients. The antitumor activity of the combination therapy was CD8 dependent and controlled growth of syngeneic tumors even when an adoptive immunotherapy was not used. Lymphocytes resulting from the combination therapy could be transferred into naïve mice to inhibit aggressive growth of lung metastases. The combination therapy enhanced CD8 memory formation as determined by memory markers and functional studies of immune recall. Removal of FoxP3-expressing T lymphocytes was the mechanism underlying immunologic memory formation following CD4 depletion. This was confirmed using transgenic DEREG (depletion of regulatory T cells) mice to specifically remove Foxp3(+) T cells. It was further confirmed with reciprocal studies where stimulation of immunologic memory because of CD4 depletion was completely neutralized by adoptively transferring tumor-specific Foxp3(+) T cells. Also contributing to tumor control, Tregs that eventually recovered following CD4 depletion were less immunosuppressive. These results provide a rationale for further study of mTOR inhibition and CD4 depletion in patients.

  6. Poly(L-lactide) crystallization topography directs MC3T3-E1 cells response.

    PubMed

    Li, Wenqiang; Lu, Lu; Jiao, Yanpeng; Zhang, Chaowen; Zhou, Changren

    2016-09-01

    Biomaterial surface topography significantly influences cellular form and function. Using poly(L-lactic acid) films with normal spherulites, banded spherulites, and amorphous surfaces as model substrates, we conducted a systematic assessment of the role for polymer crystallization induced surface morphologies on cell growth and contact guidance. Microscopy and image analysis showed that the MC3T3-E1 cells spread out in a random fashion on the amorphous substrate. At 24 h post-seeding, MC3T3-E1 cells on both types of spherulite surfaces were elongated and aligned along the spherulite radius direction. For the banded spherulite surface with radial stripes and coupling annular grooves, the cell orientation and cell nuclear localization were related to the grooves structure. With increasing time, this orientation preference was weaker. These results demonstrate that the patterning of polymer crystallization structure provide important signals for guiding cells to exhibit characteristic orientation and morphology especially in the early stages of regeneration. PMID:27376548

  7. Characterization of VAMP isoforms in 3T3-L1 adipocytes: implications for GLUT4 trafficking.

    PubMed

    Sadler, Jessica B A; Bryant, Nia J; Gould, Gwyn W

    2015-02-01

    The fusion of GLUT4-containing vesicles with the plasma membrane of adipocytes is a key facet of insulin action. This process is mediated by the formation of functional soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes between the plasma membrane t-SNARE complex and the vesicle v-SNARE or VAMP. The t-SNARE complex consists of Syntaxin4 and SNAP23, and whereas many studies identify VAMP2 as the v-SNARE, others suggest that either VAMP3 or VAMP8 may also fulfil this role. Here we characterized the levels of expression, distribution, and association of all the VAMPs expressed in 3T3-L1 adipocytes to provide the first systematic analysis of all members of this protein family for any cell type. Despite our finding that all VAMP isoforms form SDS-resistant SNARE complexes with Syntaxin4/SNAP23 in vitro, a combination of levels of expression (which vary by >30-fold), subcellular distribution, and coimmunoprecipitation analyses lead us to propose that VAMP2 is the major v-SNARE involved in GLUT4 trafficking to the surface of 3T3-L1 adipocytes.

  8. Characterization of VAMP isoforms in 3T3-L1 adipocytes: implications for GLUT4 trafficking

    PubMed Central

    Sadler, Jessica B. A.; Bryant, Nia J.; Gould, Gwyn W.

    2015-01-01

    The fusion of GLUT4-containing vesicles with the plasma membrane of adipocytes is a key facet of insulin action. This process is mediated by the formation of functional soluble N-ethylmaleimide–sensitive factor attachment protein receptor (SNARE) complexes between the plasma membrane t-SNARE complex and the vesicle v-SNARE or VAMP. The t-SNARE complex consists of Syntaxin4 and SNAP23, and whereas many studies identify VAMP2 as the v-SNARE, others suggest that either VAMP3 or VAMP8 may also fulfil this role. Here we characterized the levels of expression, distribution, and association of all the VAMPs expressed in 3T3-L1 adipocytes to provide the first systematic analysis of all members of this protein family for any cell type. Despite our finding that all VAMP isoforms form SDS-resistant SNARE complexes with Syntaxin4/SNAP23 in vitro, a combination of levels of expression (which vary by >30-fold), subcellular distribution, and coimmunoprecipitation analyses lead us to propose that VAMP2 is the major v-SNARE involved in GLUT4 trafficking to the surface of 3T3-L1 adipocytes. PMID:25501368

  9. How the blind "see" Braille: lessons from functional magnetic resonance imaging.

    PubMed

    Sadato, Norihiro

    2005-12-01

    What does the visual cortex of the blind do during Braille reading? This process involves converting simple tactile information into meaningful patterns that have lexical and semantic properties. The perceptual processing of Braille might be mediated by the somatosensory system, whereas visual letter identity is accomplished within the visual system in sighted people. Recent advances in functional neuroimaging techniques, such as functional magnetic resonance imaging, have enabled exploration of the neural substrates of Braille reading. The primary visual cortex of early-onset blind subjects is functionally relevant to Braille reading, suggesting that the brain shows remarkable plasticity that potentially permits the additional processing of tactile information in the visual cortical areas.

  10. Precision calibration procedure for magnetic loss testers using a digital two-channel function generator

    NASA Astrophysics Data System (ADS)

    Ahlers, H.

    1994-05-01

    For the precision calibration of power meters used for magnetic loss measurements, a two-channel precision generator developed at the PTB is used. The staircase functions of the generator matched to the wattmeters by a current and voltage amplifier are smoothed by low-pass Bessel filters. The complex transfer functions of the filters have been measured for different ranges of voltage, current and frequency. The waveforms to be generated are corrected by means of fast Fourier transformation (FFT) and by multiplying the Fourier coefficients by the inverse complex transfer function. The accuracy of this calibration procedure was estimated to be 0.1%.

  11. Analysis of the Role of Lead Resistivity in Specific Absorption Rate for Deep Brain Stimulator Leads at 3T MRI

    PubMed Central

    Angelone, Leonardo M.; Ahveninen, Jyrki; Belliveau, John W.; Bonmassar, Giorgio

    2011-01-01

    Magnetic resonance imaging (MRI) on patients with implanted deep brain stimulators (DBSs) can be hazardous because of the antenna-effect of leads exposed to the incident radio-frequency field. This study evaluated electromagnetic field and specific absorption rate (SAR) changes as a function of lead resistivity on an anatomically precise head model in a 3T system. The anatomical accuracy of our head model allowed for detailed modeling of the path of DBS leads between epidermis and the outer table. Our electromagnetic finite difference time domain (FDTD) analysis showed significant changes of 1 g and 10 g averaged SAR for the range of lead resistivity modeled, including highly conductive leads up to highly resistive leads. Antenna performance and whole-head SAR were sensitive to the presence of the DBS leads only within 10%, while changes of over one order of magnitude were observed for the peak 10 g averaged SAR, suggesting that local SAR values should be considered in DBS guidelines. With ρlead = ρcopper, and the MRI coil driven to produce a whole-head SAR without leads of 3.2 W/kg, the 1 g averaged SAR was 1080 W/kg and the 10 g averaged SAR 120 W/kg at the tip of the DBS lead. Conversely, in the control case without leads, the 1 g and 10 g averaged SAR were 0.5 W/kg and 0.6 W/kg, respectively, in the same location. The SAR at the tip of lead was similar with electrically homogeneous and electrically heterogeneous models. Our results show that computational models can support the development of novel lead technology, properly balancing the requirements of SAR deposition at the tip of the lead and power dissipation of the system battery. PMID:20335090

  12. A Novel Data-Driven Approach to Preoperative Mapping of Functional Cortex Using Resting-State Functional Magnetic Resonance Imaging

    PubMed Central

    Mitchell, Timothy J.; Hacker, Carl D.; Breshears, Jonathan D.; Szrama, Nick P.; Sharma, Mohit; Bundy, David T.; Pahwa, Mrinal; Corbetta, Maurizio; Snyder, Abraham Z.; Shimony, Joshua S.

    2013-01-01

    BACKGROUND: Recent findings associated with resting-state cortical networks have provided insight into the brain's organizational structure. In addition to their neuroscientific implications, the networks identified by resting-state functional magnetic resonance imaging (rs-fMRI) may prove useful for clinical brain mapping. OBJECTIVE: To demonstrate that a data-driven approach to analyze resting-state networks (RSNs) is useful in identifying regions classically understood to be eloquent cortex as well as other functional networks. METHODS: This study included 6 patients undergoing surgical treatment for intractable epilepsy and 7 patients undergoing tumor resection. rs-fMRI data were obtained before surgery and 7 canonical RSNs were identified by an artificial neural network algorithm. Of these 7, the motor and language networks were then compared with electrocortical stimulation (ECS) as the gold standard in the epilepsy patients. The sensitivity and specificity for identifying these eloquent sites were calculated at varying thresholds, which yielded receiver-operating characteristic (ROC) curves and their associated area under the curve (AUC). RSNs were plotted in the tumor patients to observe RSN distortions in altered anatomy. RESULTS: The algorithm robustly identified all networks in all patients, including those with distorted anatomy. When all ECS-positive sites were considered for motor and language, rs-fMRI had AUCs of 0.80 and 0.64, respectively. When the ECS-positive sites were analyzed pairwise, rs-fMRI had AUCs of 0.89 and 0.76 for motor and language, respectively. CONCLUSION: A data-driven approach to rs-fMRI may be a new and efficient method for preoperative localization of numerous functional brain regions. ABBREVIATIONS: AUC, area under the curve BA, Brodmann area BOLD, blood oxygen level dependent ECS, electrocortical stimulation fMRI, functional magnetic resonance imaging ICA, independent component analysis MLP, multilayer perceptron MP

  13. Rapid magnetic solid-phase extraction for the selective determination of isoflavones in soymilk using baicalin-functionalized magnetic nanoparticles

    PubMed Central

    Qing, Lin-Sen; Xue, Ying; Liu, Yi-Ming; Liang, Jian; Xie, Jing; Liao, Xun

    2013-01-01

    Most protocols of sample preparation for isoflavone determination in soymilk and other liquid soybean products involves tedious freeze drying and time-consuming extraction procedures. We report a facile and rapid magnetic solid phase extraction (MSPE) of isoflavones from soymilk for subsequent HPLC–ESI-MS/MS analysis. The extraction was based on the selective binding of isoflavones to baicalin functionalized core-shell magnetic nanoparticles (BMNPs). The proposed MSPE-HPLC-MS/MS analytical method had a linear calibration curve in the concentration range from 0.3 to 80 mg/L isoflavones. With the use of calycosin, an isomer of one of the isoflavones targeted as internal standard, inter-day (5 days) precisions of the slope and intercept of the calibration curves were found to be in the range between 2.5% and 3.6% (RSD, n = 5). Six isoflavones, i.e. daidzein, glycitein, genistein, daidzin, glycitin, and genistin were detected in commercial soymilk samples and quantified by the proposed analytical method. The results indicated that the method was useful for fast determination of isoflavones in soymilk and other liquid soybean products. PMID:23898976

  14. Voxel-Wise Functional Connectomics Using Arterial Spin Labeling Functional Magnetic Resonance Imaging: The Role of Denoising.

    PubMed

    Liang, Xiaoyun; Connelly, Alan; Calamante, Fernando

    2015-11-01

    The objective of this study was to investigate voxel-wise functional connectomics using arterial spin labeling (ASL) functional magnetic resonance imaging (fMRI). Since ASL signal has an intrinsically low signal-to-noise ratio (SNR), the role of denoising is evaluated; in particular, a novel denoising method, dual-tree complex wavelet transform (DT-CWT) combined with the nonlocal means (NLM) algorithm is implemented and evaluated. Simulations were conducted to evaluate the performance of the proposed method in denoising images and in detecting functional networks from noisy data (including the accuracy and sensitivity of detection). In addition, denoising was applied to in vivo ASL datasets, followed by network analysis using graph theoretical approaches. Efficiencies cost was used to evaluate the performance of denoising in detecting functional networks from in vivo ASL fMRI data. Simulations showed that denoising is effective in detecting voxel-wise functional networks from low SNR data and/or from data with small total number of time points. The capability of denoised voxel-wise functional connectivity analysis was also demonstrated with in vivo data. We concluded that denoising is important for voxel-wise functional connectivity using ASL fMRI and that the proposed DT-CWT-NLM method should be a useful ASL preprocessing step.

  15. Simple enrichment of thiol-containing biomolecules by using zinc(II)-cyclen-functionalized magnetic beads.

    PubMed

    Fujioka, Haruto; Tsunehiro, Masaya; Kawaguchi, Maho; Kuramoto, Yasuhiro; Kurosaki, Hiromasa; Hieda, Yuhzo; Kinoshita-Kikuta, Emiko; Kinoshita, Eiji; Koike, Tohru

    2014-07-01

    A simple and efficient method based on magnetic-bead technology has been developed for the enrichment of thiol-containing biomolecules, such as l-glutathione and cysteine-containing peptides. The thiol-binding site on the bead is a mononuclear complex of zinc(II) with 1,4,7,10-tetraazacyclododecane (cyclen); this is linked to a hydrophilic cross-linked agarose coating on a particle that has a magnetic core. All steps for the thiol-affinity separation are conducted in aqueous buffers with 0.10 mL of the magnetic beads in a 1.5 mL microtube. The entire separation protocol for thiol-containing compounds, from addition to elution, requires less than one hour per sample, provided the buffers and the zinc(II)-cyclen-functionalized magnetic beads have been prepared in advance. The thiol-affinity magnetic beads are reusable at least 15 times without a decrease in their thiol-binding ability, and they are stable for six months at room temperature.

  16. Calculation of the magnetic surface function gradient in stellarators with broken stellarator symmetry

    SciTech Connect

    Nemov, V. V.; Kasilov, S. V.; Kernbichler, W.; Seiwald, B.

    2010-05-15

    The computation of the gradient of the magnetic surface function, nablapsi, plays an essential role in plasma physics, e.g., for investigations of plasma equilibrium currents or transport fluxes in stellarators. The evaluation of nablapsi becomes more complicated if the magnetic field B does not exhibit stellarator symmetry. Here, a scheme for computation of nablapsi for magnetic configurations which do not show stellarator symmetry is presented. The proposed method is based on computations of gradients of integrals of magnetic field line equations. This new technique for nablapsi calculations is applied to Uragan-2M [O. S. Pavlichenko for the U-2M group, Plasma Phys. Controlled Fusion 35, B223 (1993)]. Taking into account the influence of current feeds and detachable joints of the helical winding the magnetic configuration does not exhibit stellarator symmetry. Computations of nablapsi, the effective ripple epsilon{sub eff}, and the geometrical factor lambda{sub b} for the bootstrap current in the 1/nu transport regime are performed.

  17. Ion energy-angle distribution functions at the plasma-material interface in oblique magnetic fields

    SciTech Connect

    Khaziev, Rinat; Curreli, Davide

    2015-04-15

    The ion energy-angle distribution (IEAD) at the wall of a magnetized plasma is of fundamental importance for the determination of the material processes occurring at the plasma-material interface, comprising secondary emissions and material sputtering. Here, we present a numerical characterization of the IEAD at the wall of a weakly collisional magnetized plasma with the magnetic field inclined at an arbitrary angle with respect to the wall. The analysis has been done using two different techniques: (1) a fluid-Monte Carlo method, and (2) particle-in-cell simulations, the former offering a fast but approximate method for the determination of the IEADs, the latter giving a computationally intensive but self-consistent treatment of the plasma behavior from the quasi-neutral region to the material boundary. The two models predict similar IEADs, whose similarities and differences are discussed. Data are presented for magnetic fields inclined at angles from normal to grazing incidence (0°–85°). We show the scaling factors of the average and peak ion energy and trends of the pitch angle at the wall as a function of the magnetic angle, for use in the correlation of fluid plasma models to material models.

  18. Comparison and functionalization study of microemulsion-prepared magnetic iron oxide nanoparticles.

    PubMed

    Okoli, Chuka; Sanchez-Dominguez, Margarita; Boutonnet, Magali; Järås, Sven; Civera, Concepción; Solans, Conxita; Kuttuva, Gunaratna Rajarao

    2012-06-01

    Magnetic iron oxide nanoparticles (MION) for protein binding and separation were obtained from water-in-oil (w/o) and oil-in-water (o/w) microemulsions. Characterization of the prepared nanoparticles have been performed by TEM, XRD, SQUID magnetometry, and BET. Microemulsion-prepared magnetic iron oxide nanoparticles (ME-MION) with sizes ranging from 2 to 10 nm were obtained. Study on the magnetic properties at 300 K shows a large increase of the magnetization ~35 emu/g for w/o-ME-MION with superparamagnetic behavior and nanoscale dimensions in comparison with o/w-ME-MION (10 emu/g) due to larger particle size and anisotropic property. Moringa oleifera coagulation protein (MOCP) bound w/o- and o/w-ME-MION showed an enhanced performance in terms of coagulation activity. A significant interaction between the magnetic nanoparticles and the protein can be described by changes in fluorescence emission spectra. Adsorbed protein from MOCP is still retaining its functionality even after binding to the nanoparticles, thus implying the extension of this technique for various applications. PMID:22578053

  19. Hydrazide functionalized core-shell magnetic nanocomposites for highly specific enrichment of N-glycopeptides.

    PubMed

    Liu, Liting; Yu, Meng; Zhang, Ying; Wang, Changchun; Lu, Haojie

    2014-05-28

    In view of the biological significance of glycosylation for human health, profiling of glycoproteome from complex biological samples is highly inclined toward the discovery of disease biomarkers and clinical diagnosis. Nevertheless, because of the existence of glycopeptides at relatively low abundances compared with nonglycosylated peptides and glycan microheterogeneity, glycopeptides need to be highly selectively enriched from complex biological samples for mass spectrometry analysis. Herein, a new type of hydrazide functionalized core-shell magnetic nanocomposite has been synthesized for highly specific enrichment of N-glycopeptides. The nanocomposites with both the magnetic core and the polymer shell hanging high density of hydrazide groups were prepared by first functionalization of the magnetic core with polymethacrylic acid by reflux precipitation polymerization to obtain the Fe3O4@poly(methacrylic acid) (Fe3O4@PMAA) and then modification of the surface of Fe3O4@PMAA with adipic acid dihydrazide (ADH) to obtain Fe3O4@poly(methacrylic hydrazide) (Fe3O4@PMAH). The abundant hydrazide groups toward highly specific enrichment of glycopeptides and the magnetic core make it suitable for large-scale, high-throughput, and automated sample processing. In addition, the hydrophilic polymer surface can provide low nonspecific adsorption of other peptides. Compared to commercially available hydrazide resin, Fe3O4@PMAH improved more than 5 times the signal-to-noise ratio of standard glycopeptides. Finally, this nanocomposite was applied in the profiling of N-glycoproteome from the colorectal cancer patient serum. In total, 175 unique glycopeptides and 181 glycosylation sites corresponding to 63 unique glycoproteins were identified in three repeated experiments, with the specificities of the enriched glycopeptides and corresponding glycoproteins of 69.6% and 80.9%, respectively. Because of all these attractive features, we believe that this novel hydrazide functionalized

  20. Functional expression of an scFv on bacterial magnetic particles by in vitro docking

    SciTech Connect

    Sugamata, Yasuhiro; Tanaka, Tsuyoshi; Matsunaga, Tadashi; Yoshino, Tomoko

    2014-02-28

    Highlights: • We present a novel expression system called “in vitro docking” on bacterial magnetic particles. • An scFv–Fc was functionally expressed on bacterial magnetic particles of magnetotactic bacteria. • Our novel expression system on BacMPs will be effective for disulfide-bonded proteins. - Abstract: A Gram-negative, magnetotactic bacterium, Magnetospirillum magneticum AMB-1 produces nano-sized magnetic particles (BacMPs) in the cytoplasm. Although various applications of genetically engineered BacMPs have been demonstrated, such as immunoassay, ligand–receptor interaction or cell separation, by expressing a target protein on BacMPs, it has been difficult to express disulfide-bonded proteins on BacMPs due to lack of disulfide-bond formation in the cytoplasm. Here, we propose a novel dual expression system, called in vitro docking, of a disulfide-bonded protein on BacMPs by directing an immunoglobulin Fc-fused target protein to the periplasm and its docking protein ZZ on BacMPs. By in vitro docking, an scFv–Fc fusion protein was functionally expressed on BacMPs in the dimeric or trimeric form. Our novel disulfide-bonded protein expression system on BacMPs will be useful for efficient screening of potential ligands or drugs, analyzing ligand–receptor interactions or as a magnetic carrier for affinity purification.

  1. Isolation of N-linked glycopeptides by hydrazine-functionalized magnetic particles.

    PubMed

    Sun, Shisheng; Yang, Ganglong; Wang, Ting; Wang, Qinzhe; Chen, Chao; Li, Zheng

    2010-04-01

    We introduce a novel combination of magnetic particles with hydrazine chemistry, dubbed as hydrazine-functionalized magnetic particles (HFMP) for isolation of glycopeptides. Four methods have been developed and compared for the production of HFMP by hydrazine modification of the surface of the carboxyl and epoxy-silanized magnetic particles, respectively. The evaluation of the capability and specificity of HFMP as well as the optimization of the coupling condition for capturing of glycoproteins were systematically investigated. The results showed that HFMP prepared by adipic dihydrazide functionalization from carboxyl-silanized magnetic particles (HFCA) displayed the maximum capture capacity and isolated efficiency for glycoprotein. When measured with glycoproteins, the capacity of the HFCA (1 g) for coupling bovine fetuin was 130 +/- 5.3 mg. The capability of this method was also confirmed by successful isolation of all formerly glycosylated peptides from standard glycoproteins and identification of their glycosylation sites, which demonstrated the feasibility of the HFCA as an alternative solid support for isolation of glycoproteins/glycopeptides. PMID:20169334

  2. Development of magnetic resonance imaging based detection methods for beta amyloids via sialic acid-functionalized magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Kouyoumdjian, Hovig

    The development of a non-invasive method for the detection of Alzheimer's disease is of high current interest, which can be critical in early diagnosis and in guiding preventive treatment of the disease. The aggregates of beta amyloids are a pathological hallmark of Alzheimer's disease. Carbohydrates such as sialic acid terminated gangliosides have been shown to play significant roles in initiation of amyloid aggregation. Herein, we report a biomimetic approach using sialic acid coated iron oxide superparamagnetic nanoparticles for in vitro detection in addition to the assessment of the in vivo mouse-BBB (Blood brain barrier) crossing of the BSA (bovine serum albumin)-modified ones. The sialic acid functionalized dextran nanoparticles were shown to bind with beta amyloids through several techniques including ELISA (enzyme linked immunosorbent assay), MRI (magnetic resonance imaging), TEM (transmission electron microscopy), gel electrophoresis and tyrosine fluorescence assay. The superparamagnetic nature of the nanoparticles allowed easy detection of the beta amyloids in mouse brains in both in vitro and ex vivo model by magnetic resonance imaging. Furthermore, the sialic acid nanoparticles greatly reduced beta amyloid induced cytotoxicity to SH-SY5Y neuroblastoma cells, highlighting the potential of the glyconanoparticles for detection and imaging of beta amyloids. Sialic acid functionalized BSA (bovine serum albumin) nanoparticles also showed significant binding to beta amyloids, through ELISA and ex vivo mouse brain MRI experiments. Alternatively, the BBB crossing was demonstrated by several techniques such as confocal microscopy, endocytosis, exocytosis assays and were affirmed by nanoparticles transcytosis assays through bEnd.3 endothelial cells. Finally, the BBB crossing was confirmed by analyzing the MRI signal of nanoparticle-injected CD-1 mice.

  3. Functional mapping of the human visual cortex by magnetic resonance imaging

    SciTech Connect

    Belliveau, J.W.; Kennedy, D.N.; McKinstry, R.C.; Buchbinder, B.R.; Weisskoff, R.M.; Cohen, M.S.; Vevea, J.M.; Brady, T.J.; Rosen, B.R. Harvard Medical School, Boston, MA )

    1991-11-01

    Knowledge of regional cerebral hemodynamics has widespread application for both physiological research and clinical assessment because of the well-established interrelation between physiological function, energy metabolism, and localized blood supply. A magnetic resonance technique was developed for quantitative imaging of cerebral hemodynamics, allowing for measurement of regional cerebral blood volume during resting and activated cognitive states. This technique was used to generate the first functional magnetic resonance amps of human task activation, by using a visual stimulus paradigm. During photic stimulation, localized increases in blood volume (32 {plus minus} 10%, n = 7 subjects) were detected in the primary visual cortex. Center-of-mass coordinates and linear extends of brain activation within the plane of the calcarine fissure are reported.

  4. Functional magnetic resonance microscopy at single-cell resolution in Aplysia californica

    PubMed Central

    Radecki, Guillaume; Nargeot, Romuald; Jelescu, Ileana Ozana; Le Bihan, Denis; Ciobanu, Luisa

    2014-01-01

    In this work, we show the feasibility of performing functional MRI studies with single-cell resolution. At ultrahigh magnetic field, manganese-enhanced magnetic resonance microscopy allows the identification of most motor neurons in the buccal network of Aplysia at low, nontoxic Mn2+ concentrations. We establish that Mn2+ accumulates intracellularly on injection into the living Aplysia and that its concentration increases when the animals are presented with a sensory stimulus. We also show that we can distinguish between neuronal activities elicited by different types of stimuli. This method opens up a new avenue into probing the functional organization and plasticity of neuronal networks involved in goal-directed behaviors with single-cell resolution. PMID:24872449

  5. Shared and differential neural substrates of copying versus drawing: a functional magnetic resonance imaging study.

    PubMed

    Ferber, Susanne; Mraz, Richard; Baker, Nicole; Graham, Simon J

    2007-07-16

    Copying and drawing-from-memory tasks are popular clinical tests to assess visuo-motor skills in neurological patients. The tasks share some motor and visual processes; however, they differ substantially in their cognitive demands. We used functional magnetic resonance imaging to identify brain regions underlying processes involved in these tasks while avoiding confounds related to basic motor requirements, through use of a specially developed functional magnetic resonance imaging-compatible computer tablet. For the copying task, activation was observed in brain regions subserving visual processing and crossmodal attention (e.g. left lingual gyrus, cuneus). Drawing activated the anterior cingulate, an area associated with motor control and linking intention with action. These findings suggest distinct neural networks subserving copying and drawing.

  6. Low-energy ion distribution functions on a magnetically quiet day at geostationary altitude /L = 7/

    NASA Technical Reports Server (NTRS)

    Singh, N.; Raitt, W. J.; Yasuhara, F.

    1982-01-01

    Ion energy and pitch angle distribution functions are examined for a magnetically quiet day using averaged data from ATS 6. For both field-aligned and perpendicular fluxes, the populations have a mixture of characteristic energies, and the distribution functions can be fairly well approximated by Maxwellian distributions over three different energy bands in the range 3-600 eV. Pitch angle distributions varying with local time, and energy distributions are used to compute total ion density. Pitch angle scattering mechanisms responsible for the observed transformation of pitch angle distribution are examined, and it is found that a magnetic noise of a certain power spectral density belonging to the electromagnetic ion cyclotron mode near the ion cyclotron frequency can be effective in trapping the field aligned fluxes by pitch angle scattering.

  7. Nature versus nurture: Functional assessment of restoration effects on wetland services using Nuclear Magnetic Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sundareshwar, P. V.; Richardson, C. J.; Gleason, Robert A.; Pellechia, Perry J.; Honomichl, Shawn

    2009-02-01

    Land-use change has altered the ability of wetlands to provide vital services such as nutrient retention. While compensatory practices attempt to restore degraded wetlands and their functions, it is difficult to evaluate the recovery of soil biogeochemical functions that are critical for restoration of ecosystem services. Using solution 31P Nuclear Magnetic Resonance Spectroscopy, we examined the chemical forms of phosphorus (P) in soils from wetlands located across a land-use gradient. We report that soil P diversity, a functional attribute, was lowest in farmland, and greatest in native wetlands. Soil P diversity increased with age of restoration, indicating restoration of biogeochemical function. The trend in soil P diversity was similar to documented trends in soil bacterial taxonomic composition but opposite that of soil bacterial diversity at our study sites. These findings provide insights into links between ecosystem structure and function and provide a tool for evaluating the success of ecosystem restoration efforts.

  8. Functionalization of PEGylated Fe3O4 magnetic nanoparticles with tetraphosphonate cavitand for biomedical application

    NASA Astrophysics Data System (ADS)

    Tudisco, C.; Bertani, F.; Cambria, M. T.; Sinatra, F.; Fantechi, E.; Innocenti, C.; Sangregorio, C.; Dalcanale, E.; Condorelli, G. G.

    2013-11-01

    In this contribution, Fe3O4 magnetic nanoparticles (MNPs) have been functionalized with a tetraphosphonate cavitand receptor (Tiiii), capable of complexing N-monomethylated species with high selectivity, and polyethylene glycol (PEG) via click-chemistry. The grafting process is based on MNP pre-functionalization with a bifunctional phosphonic linker, 10-undecynylphosphonic acid, anchored on an iron surface through the phosphonic group. The Tiiii cavitand and the PEG modified with azide moieties have then been bonded to the resulting alkyne-functionalized MNPs through a ``click'' reaction. Each reaction step has been monitored by using X-ray photoelectron and FTIR spectroscopies. PEG and Tiiii functionalized MNPs have been able to load N-methyl ammonium salts such as the antitumor drug procarbazine hydrochloride and the neurotransmitter epinephrine hydrochloride and release them as free bases. In addition, the introduction of PEG moieties promoted biocompatibility of functionalized MNPs, thus allowing their use in biological environments.

  9. Nature versus nurture: functional assessment of restoration effects on wetland services using Nuclear Magnetic Resonance Spectroscopy

    USGS Publications Warehouse

    Sundareshwar, P.V.; Richardson, C.J.; Gleason, R.A.; Pellechia, P.J.; Honomichl, S.

    2009-01-01

    Land-use change has altered the ability of wetlands to provide vital services such as nutrient retention. While compensatory practices attempt to restore degraded wetlands and their functions, it is difficult to evaluate the recovery of soil biogeochemical functions that are critical for restoration of ecosystem services. Using solution 31P Nuclear Magnetic Resonance Spectroscopy, we examined the chemical forms of phosphorus (P) in soils from wetlands located across a land-use gradient. We report that soil P diversity, a functional attribute, was lowest in farmland, and greatest in native wetlands. Soil P diversity increased with age of restoration, indicating restoration of biogeochemical function. The trend in soil P diversity was similar to documented trends in soil bacterial taxonomic composition but opposite that of soil bacterial diversity at our study sites. These findings provide insights into links between ecosystem structure and function and provide a tool for evaluating the success of ecosystem restoration efforts. Copyright 2009 by the American Geophysical Union.

  10. MR images of mouse brain using clinical 3T MR scanner and 4CH-Mouse coil

    NASA Astrophysics Data System (ADS)

    Lim, Soo Mee; Park, Eun Mi; Lyoo, In Kyoon; Lee, Junghyun; Han, Bo Mi; Lee, Jeong Kyong; Lee, Su Bin

    2015-07-01

    Objectives: Although small-bore high-field magnets are useful for research in small rodent models,this technology, however, has not been easily accessible to most researchers. This current study, thus,tried to evaluate the usability of 4CH-Mouse coil (Philips Healthcare, Best, the Netherlands) forpreclinical investigations in clinical 3T MR scan environment. We evaluated the effects of ischemicpreconditioning (IP) in the mouse stroke model with clinical 3T MR scanner and 4CH-Mouse coil. Materials and Methods: Experiments were performed on male C57BL/6 mice that either received the IP or sham operation (control). Three different MR sequences including diffusion weighted images (DWI), T2-weighted images (T2WI), and fluid attenuated inversion recovery (FLAIR) were performed on the mouse brains following 24, 72 hours of middle cerebral artery occlusion (MCAO) and analyzed for infarct lesions. Results: The images showed that the IP-treated mouse brains had significantly smaller infarct volumes compared to the control group. Of the MR sequences employed, the T2WI showed the highest level of correlations with postmortem infarct volume measurements. Conclusions: The clinical 3T MR scanner turned out to have a solid potential as a practical tool for imaging small animal brains. MR sequences including DWI, T2WI, FLAIR were obtained with acceptable resolution and in a reasonable time constraint in evaluating a mouse stroke model brain.

  11. Extraction of Weak Transition Strengths via the (He3, t) Reaction at 420MeV

    NASA Astrophysics Data System (ADS)

    Zegers, R. G. T.; Adachi, T.; Akimune, H.; Austin, Sam M.; van den Berg, A. M.; Brown, B. A.; Fujita, Y.; Fujiwara, M.; Galès, S.; Guess, C. J.; Harakeh, M. N.; Hashimoto, H.; Hatanaka, K.; Hayami, R.; Hitt, G. W.; Howard, M. E.; Itoh, M.; Kawabata, T.; Kawase, K.; Kinoshita, M.; Matsubara, M.; Nakanishi, K.; Nakayama, S.; Okumura, S.; Ohta, T.; Sakemi, Y.; Shimbara, Y.; Shimizu, Y.; Scholl, C.; Simenel, C.; Tameshige, Y.; Tamii, A.; Uchida, M.; Yamagata, T.; Yosoi, M.

    2007-11-01

    Differential cross sections for transitions of known weak strength were measured with the (He3, t) reaction at 420 MeV on targets of C12, C13, O18, Mg26, Ni58, Ni60, Zr90, Sn118, Sn120, and Pb208. Using these data, it is shown that the proportionalities between strengths and cross sections for this probe follow simple trends as a function of mass number. These trends can be used to confidently determine Gamow-Teller strength distributions in nuclei for which the proportionality cannot be calibrated via β-decay strengths. Although theoretical calculations in the distorted-wave Born approximation overestimate the data, they allow one to understand the main experimental features and to predict deviations from the simple trends observed in some of the transitions.

  12. Early functional magnetic resonance imaging activations predict language outcome after stroke.

    PubMed

    Saur, Dorothee; Ronneberger, Olaf; Kümmerer, Dorothee; Mader, Irina; Weiller, Cornelius; Klöppel, Stefan

    2010-04-01

    An accurate prediction of system-specific recovery after stroke is essential to provide rehabilitation therapy based on the individual needs. We explored the usefulness of functional magnetic resonance imaging scans from an auditory language comprehension experiment to predict individual language recovery in 21 aphasic stroke patients. Subjects with an at least moderate language impairment received extensive language testing 2 weeks and 6 months after left-hemispheric stroke. A multivariate machine learning technique was used to predict language outcome 6 months after stroke. In addition, we aimed to predict the degree of language improvement over 6 months. 76% of patients were correctly separated into those with good and bad language performance 6 months after stroke when based on functional magnetic resonance imaging data from language relevant areas. Accuracy further improved (86% correct assignments) when age and language score were entered alongside functional magnetic resonance imaging data into the fully automatic classifier. A similar accuracy was reached when predicting the degree of language improvement based on imaging, age and language performance. No prediction better than chance level was achieved when exploring the usefulness of diffusion weighted imaging as well as functional magnetic resonance imaging acquired two days after stroke. This study demonstrates the high potential of current machine learning techniques to predict system-specific clinical outcome even for a disease as heterogeneous as stroke. Best prediction of language recovery is achieved when the brain activation potential after system-specific stimulation is assessed in the second week post stroke. More intensive early rehabilitation could be provided for those with a predicted poor recovery and the extension to other systems, for example, motor and attention seems feasible. PMID:20299389

  13. Impact of a High Magnetic Field on the Orientation of Gravitactic Unicellular Organisms—A Critical Consideration about the Application of Magnetic Fields to Mimic Functional Weightlessness

    PubMed Central

    Simon, Anja; Waßer, Kai; Hauslage, Jens; Christianen, Peter C.M.; Albers, Peter W.; Lebert, Michael; Richter, Peter; Alt, Wolfgang; Anken, Ralf

    2014-01-01

    Abstract The gravity-dependent behavior of Paramecium biaurelia and Euglena gracilis have previously been studied on ground and in real microgravity. To validate whether high magnetic field exposure indeed provides a ground-based facility to mimic functional weightlessness, as has been suggested earlier, both cell types were observed during exposure in a strong homogeneous magnetic field (up to 30 T) and a strong magnetic field gradient. While swimming, Paramecium cells were aligned along the magnetic field lines; orientation of Euglena was perpendicular, demonstrating that the magnetic field determines the orientation and thus prevents the organisms from the random swimming known to occur in real microgravity. Exposing Astasia longa, a flagellate that is closely related to Euglena but lacks chloroplasts and the photoreceptor, as well as the chloroplast-free mutant E. gracilis 1F, to a high magnetic field revealed no reorientation to the perpendicular direction as in the case of wild-type E. gracilis, indicating the existence of an anisotropic structure (chloroplasts) that determines the direction of passive orientation. Immobilized Euglena and Paramecium cells could not be levitated even in the highest available magnetic field gradient as sedimentation persisted with little impact of the field on the sedimentation velocities. We conclude that magnetic fields are not suited as a microgravity simulation for gravitactic unicellular organisms due to the strong effect of the magnetic field itself, which masks the effects known from experiments in real microgravity. Key Words: Levitation—Microgravity—Gravitaxis—Gravikinesis—Gravity. Astrobiology 14, 205–215. PMID:24621307

  14. Impact of a high magnetic field on the orientation of gravitactic unicellular organisms--a critical consideration about the application of magnetic fields to mimic functional weightlessness.

    PubMed

    Hemmersbach, Ruth; Simon, Anja; Waßer, Kai; Hauslage, Jens; Christianen, Peter C M; Albers, Peter W; Lebert, Michael; Richter, Peter; Alt, Wolfgang; Anken, Ralf

    2014-03-01

    The gravity-dependent behavior of Paramecium biaurelia and Euglena gracilis have previously been studied on ground and in real microgravity. To validate whether high magnetic field exposure indeed provides a ground-based facility to mimic functional weightlessness, as has been suggested earlier, both cell types were observed during exposure in a strong homogeneous magnetic field (up to 30 T) and a strong magnetic field gradient. While swimming, Paramecium cells were aligned along the magnetic field lines; orientation of Euglena was perpendicular, demonstrating that the magnetic field determines the orientation and thus prevents the organisms from the random swimming known to occur in real microgravity. Exposing Astasia longa, a flagellate that is closely related to Euglena but lacks chloroplasts and the photoreceptor, as well as the chloroplast-free mutant E. gracilis 1F, to a high magnetic field revealed no reorientation to the perpendicular direction as in the case of wild-type E. gracilis, indicating the existence of an anisotropic structure (chloroplasts) that determines the direction of passive orientation. Immobilized Euglena and Paramecium cells could not be levitated even in the highest available magnetic field gradient as sedimentation persisted with little impact of the field on the sedimentation velocities. We conclude that magnetic fields are not suited as a microgravity simulation for gravitactic unicellular organisms due to the strong effect of the magnetic field itself, which masks the effects known from experiments in real microgravity.

  15. Fluorochrome-functionalized magnetic nanoparticles for high-sensitivity monitoring of the polymerase chain reaction by magnetic resonance.

    PubMed

    Alcantara, David; Guo, Yanyan; Yuan, Hushan; Goergen, Craig J; Chen, Howard H; Cho, Hoonsung; Sosnovik, David E; Josephson, Lee

    2012-07-01

    Easy to find: magnetic nanoparticles bearing fluorochromes (red) that intercalate with DNA (green) form microaggregates with DNA generated by the polymerase chain reaction (PCR). These aggregates can be detected at low cycle numbers by magnetic resonance (MR).

  16. Comparison of oxygen consumption rates in minimally transformed BALB/3T3 and virus-transformed 3T3B-SV40 cells.

    PubMed

    Leznev, E I; Popova, I I; Lavrovskaja, V P; Evtodienko, Y V

    2013-08-01

    In the recent years, bioenergetics of tumor cells and particularly cell respiration have been attracting great attention because of the involvement of mitochondria in apoptosis and growing evidence of the possibility to diagnose and treat cancer by affecting the system of oxidative phosphorylation in mitochondria. In the present work, a comparative study of oxygen consumption in 3T3B-SV40 cells transformed with oncovirus SV40 and parental BALB/3T3 cells was conducted. Such fractions of oxygen consumption as "phosphorylating" respiration coupled to ATP synthesis, "free" respiration not coupled to ATP synthesis, and "reserve" or hidden respiration observed in the presence of protonophore were determined. Maximal respiration was shown to be only slightly decreased in 3T3B-SV40 cells as compared to BALB/3T3. However, in the case of certain fractions of cellular respiration, the changes were significant. "Phosphorylating" respiration was found to be reduced to 54% and "reserve" respiration, on the contrary, increased up to 160% in virus-transformed 3T3B-SV40 cells. The low rate of "phosphorylating" respiration and high "reserve" respiration indicate that under normal incubation conditions the larger part of mitochondrial respiratory chains of the virus-transformed cells is in the resting state (i.e. there is no electron transfer to oxygen). The high "reserve" respiration is suggested to play an important role in preventing apoptosis of 3T3B-SV40 cells.

  17. Delineating potential epileptogenic areas utilizing resting functional magnetic resonance imaging (fMRI) in epilepsy patients.

    PubMed

    Pizarro, Ricardo; Nair, Veena; Meier, Timothy; Holdsworth, Ryan; Tunnell, Evelyn; Rutecki, Paul; Sillay, Karl; Meyerand, Mary E; Prabhakaran, Vivek

    2016-08-01

    Seizure localization includes neuroimaging like electroencephalogram, and magnetic resonance imaging (MRI) with limited ability to characterize the epileptogenic network. Temporal clustering analysis (TCA) characterizes epileptogenic network congruent with interictal epileptiform discharges by clustering together voxels with transient signals. We generated epileptogenic areas for 12 of 13 epilepsy patients with TCA, congruent with different areas of seizure onset. Resting functional MRI (fMRI) scans are noninvasive, and can be acquired quickly, in patients with different levels of severity and function. Analyzing resting fMRI data using TCA is quick and can complement clinical methods to characterize the epileptogenic network. PMID:27362339

  18. Network asymmetry of motor areas revealed by resting-state functional magnetic resonance imaging.

    PubMed

    Yan, Li-Rong; Wu, Yi-Bo; Hu, De-Wen; Qin, Shang-Zhen; Xu, Guo-Zheng; Zeng, Xiao-Hua; Song, Hua

    2012-02-01

    There are ample functional magnetic resonance imaging (fMRI) studies on functional brain asymmetries, and the asymmetry of cerebral network in the resting state may be crucial to brain function organization. In this paper, a unified schema of voxel-wise functional connectivity and asymmetry analysis was presented and the network asymmetry of motor areas was studied. Twelve healthy male subjects with mean age 29.8 ± 6.4 were studied. Functional network in the resting state was described by using functional connectivity magnetic resonance imaging (fcMRI) analysis. Motor areas were selected as regions of interest (ROIs). Network asymmetry, including intra- and inter-network asymmetries, was formulated and analyzed. The intra-network asymmetry was defined as the difference between the left and right part of a particular functional network. The inter-network asymmetry was defined as the difference between the networks for a specific ROI in the left hemisphere and its homotopic ROI in the right hemisphere. Primary motor area (M1), primary sensory area (S1) and premotor area (PMA) exhibited higher functional correlation with the right parietal-temporal-occipital circuit and the middle frontal gyrus than they did with the left hemisphere. Right S1 and right PMA exhibited higher functional correlation with the ipsilateral precentral and supramarginal areas. There exist the large-scale hierarchical network asymmetries of the motor areas in the resting state. These asymmetries imply the right hemisphere dominance for predictive motor coding based on spatial attention and higher sensory processing load for the motor performance of non-dominant hemisphere.

  19. Arrangement for measuring the field angle of a magnetic field as a function of axial position within a magnet bore tube

    DOEpatents

    Pidcoe, Stephen V.; Zink, Roger A.; Boroski, William N.; McCaw, William R.

    1993-01-01

    An arrangement for measuring the field angle of a magnetic field as a function of axial position within a magnet bore tube of a magnet such as is used with the Superconducting Super Collider (SSC). The arrangement includes a magnetic field alignment gauge that is carried through the magnet bore tube by a positioning shuttle in predetermined increments. The positioning shuttle includes an extensible body assembly which is actuated by an internal piston arrangement. A pair of spaced inflatable cuffs are carried by the body assembly and are selectively actuated in cooperation with pressurizing of the piston to selectively drive the positioning shuttle in an axial direction. Control of the shuttle is provided by programmed electronic computer means located exteriorly of the bore tube and which controls valves provided pressurized fluid to the inflatable cuss and the piston arrangement.

  20. The effects of functional magnetic nanotubes with incorporated nerve growth factor in neuronal differentiation of PC12 cells

    NASA Astrophysics Data System (ADS)

    Xie, Jining; Chen, Linfeng; Varadan, Vijay K.; Yancey, Justin; Srivatsan, Malathi

    2008-03-01

    In this in vitro study the efficiency of magnetic nanotubes to bind with nerve growth factor (NGF) and the ability of NGF-incorporated magnetic nanotubes to release the bound NGF are investigated using rat pheochromocytoma cells (PC12 cells). It is found that functional magnetic nanotubes with NGF incorporation enabled the differentiation of PC12 cells into neurons exhibiting growth cones and neurite outgrowth. Microscope observations show that filopodia extending from neuron growth cones were in close proximity to the NGF-incorporated magnetic nanotubes, at times appearing to extend towards or into them. These results show that magnetic nanotubes can be used as a delivery vehicle for NGF and thus may be exploited in attempts to treat neurodegenerative disorders such as Parkinson's disease with neurotrophins. Further neurite outgrowth can be controlled by manipulating magnetic nanotubes with external magnetic fields, thus helping in directed regeneration.

  1. Effect of Ganoderma applanatum mycelium extract on the inhibition of adipogenesis in 3T3-L1 adipocytes.

    PubMed

    Kim, Ji-Eun; Park, Sung-Jin; Yu, Mi-Hee; Lee, Sam-Pin

    2014-10-01

    Ganoderma applanatum (GA) and related fungal species have been used for over 2000 years in China to prevent and treat various human diseases. However, there is no critical research evaluating the functionality of GA grown using submerged culture technology. This study aimed to evaluate the effects of submerged culture GA mycelium (GAM) and its active components (protocatechualdehyde [PCA]) on preadipocyte differentiation of 3T3-L1 cells. Mouse-derived preadipocyte 3T3-L1 cells were treated with differentiation inducers in the presence or absence of GAM extracts. We determined triglyceride accumulations, glycerol-3-phosphate dehydrogenase (GPDH) activities, and differentiation makers. PCA, the active component of GAM extract, was also used to treat 3T3-L1 cells. The MTT assay showed that the GAM extract (0.01-1 mg/mL) was not toxic to 3T3-L1 preadipocyte. Treatment of cells with GAM extracts and its active components significantly decreased the GPDH activity and lipid accumulation, a marker of adipogenesis, in a dose-dependent manner. Western blot analysis results showed that the protein expression levels of peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding protein α (C/EBPα), and sterol regulatory element-binding protein 1 (SREBP1) were inhibited by the GAM extract. In addition, adipogenic-specific genes such as perilipin, fatty acid synthase (FAS), fatty acid transport protein 1 (FATP1), and fatty acid-binding protein 4 (FABP4) decreased in a dose-dependent manner. Quantitative high-performance liquid chromatography analysis showed that the GAM extract contained 1.14 mg/g PCA. GAM extracts suppressed differentiation of 3T3-L1 preadipocytes, in part, through altered regulation of PPARγ, C/EBPα, and SREBP1. These results suggest that GAM extracts and PCA may suppress adipogenesis by inhibiting differentiation of preadipocytes.

  2. Prediction of d^0 magnetism in self-interaction corrected density functional theory

    NASA Astrophysics Data System (ADS)

    Das Pemmaraju, Chaitanya

    2010-03-01

    Over the past couple of years, the phenomenon of ``d^0 magnetism'' has greatly intrigued the magnetism community [1]. Unlike conventional magnetic materials, ``d^0 magnets'' lack any magnetic ions with open d or f shells but surprisingly, exhibit signatures of ferromagnetism often with a Curie temperature exceeding 300 K. Current research in the field is geared towards trying to understand the mechanism underlying this observed ferromagnetism which is difficult to explain within the conventional m-J paradigm [1]. The most widely studied class of d^0 materials are un-doped and light element doped wide gap Oxides such as HfO2, MgO, ZnO, TiO2 all of which have been put forward as possible d0 ferromagnets. General experimental trends suggest that the magnetism is a feature of highly defective samples leading to the expectation that the phenomenon must be defect related. In particular, based on density functional theory (DFT) calculations acceptor defects formed from the O-2p states in these Oxides have been proposed as being responsible for the ferromagnetism [2,3]. However. predicting magnetism originating from 2p orbitals is a delicate problem, which depends on the subtle interplay between covalency and Hund's coupling. DFT calculations based on semi-local functionals such as the local spin-density approximation (LSDA) can lead to qualitative failures on several fronts. On one hand the excessive delocalization of spin-polarized holes leads to half-metallic ground states and the expectation of room-temperature ferromagnetism. On the other hand, in some cases a magnetic ground state may not be predicted at all as the Hund's coupling might be under estimated. Furthermore, polaronic distortions which are often a feature of acceptor defects in Oxides are not predicted [4,5]. In this presentation, we argue that the self interaction error (SIE) inherent to semi-local functionals is responsible for the failures of LSDA and demonstrate through various examples that beyond

  3. Characterization, prediction, and correction of geometric distortion in 3 T MR images.

    PubMed

    Baldwin, Lesley N; Wachowicz, Keith; Thomas, Steven D; Rivest, Ryan; Fallone, B Gino

    2007-02-01

    The work presented herein describes our methods and results for predicting, measuring and correcting geometric distortions in a 3 T clinical magnetic resonance (MR) scanner for the purpose of image guidance in radiation treatment planning. Geometric inaccuracies due to both inhomogeneities in the background field and nonlinearities in the applied gradients were easily visualized on the MR images of a regularly structured three-dimensional (3D) grid phantom. From a computed tomography scan, the locations of just under 10 000 control points within the phantom were accurately determined in three dimensions using a MATLAB-based computer program. MR distortion was then determined by measuring the corresponding locations of the control points when the phantom was imaged using the MR scanner. Using a reversed gradient method, distortions due to gradient nonlinearities were separated from distortions due to inhomogeneities in the background B0 field. Because the various sources of machine-related distortions can be individually characterized, distortions present in other imaging sequences (for which 3D distortion cannot accurately be measured using phantom methods) can be predicted negating the need for individual distortion calculation for a variety of other imaging sequences. Distortions were found to be primarily caused by gradient nonlinearities and maximum image distortions were reported to be less than those previously found by other researchers at 1.5 T. Finally, the image slices were corrected for distortion in order to provide geometrically accurate phantom images. PMID:17388155

  4. In vivo conductivity imaging of canine male pelvis using a 3T MREIT system

    NASA Astrophysics Data System (ADS)

    Kim, H. J.; Jeong, W. C.; Kim, Y. T.; Minhas, A. S.; Lee, T. H.; Lim, C. Y.; Park, H. M.; Seo, J. K.; Woo, E. J.

    2010-04-01

    The prostate is an imaging area of growing concern related with aging. Prostate cancer and benign prostatic hyperplasia are the most common diseases and significant cause of death for elderly men. Hence, the conductivity imaging of the male pelvis is a challenging task with a clinical significance. In this study, we performed in vivo MREIT imaging experiments of the canine male pelvis using a 3T MRI scanner. Adopting carbon-hydrogel electrodes and a multi-echo pulse sequence, we could inject as much as 10 mA current in a form of 51 ms pulse into the pelvis. Collecting magnetic flux density data inside the pelvis subject to multiple injection currents, we reconstructed cross-sectional conductivity images using a MREIT software package CoReHA. Scaled conductivity images of the prostate show a clear contrast between the central and peripheral zones which are related with prostate diseases including cancer and benign prostatic hyperplasia. In our future work, we will focus on prostate cancer model animal experiments.

  5. Improved localisation for 2-hydroxyglutarate detection at 3T using long-TE semi-LASER

    PubMed Central

    Berrington, Adam; Voets, Natalie L.; Plaha, Puneet; Larkin, Sarah J.; Mccullagh, James; Stacey, Richard; Yildirim, Muhammed; Schofield, Christopher J.; Jezzard, Peter; Cadoux-Hudson, Tom; Ansorge, Olaf; Emir, Uzay E.

    2016-01-01

    2-hydroxyglutarate (2-HG) has emerged as a biomarker of tumour cell IDH mutations that may enable the differential diagnosis of glioma patients. At 3 Tesla, detection of 2-HG with magnetic resonance spectroscopy is challenging because of metabolite signal overlap and a spectral pattern modulated by slice selection and chemical shift displacement. Using density matrix simulations and phantom experiments, an optimised semi-LASER scheme (TE = 110 ms) improves localisation of the 2-HG spin system considerably compared to an existing PRESS sequence. This results in a visible 2-HG peak in the in vivo spectra at 1.9 ppm in the majority of IDH mutated tumours. Detected concentrations of 2-HG were similar using both sequences, although the use of semi-LASER generated narrower confidence intervals. Signal overlap with glutamate and glutamine, as measured by pairwise fitting correlation was reduced. Lactate was readily detectable across glioma patients using the method presented here (mean CLRB: (10±2)%). Together with more robust 2-HG detection, long TE semi-LASER offers the potential to investigate tumour metabolism and stratify patients in vivo at 3T. PMID:27547821

  6. Comprehensive study of mesoporous carbon functionalized with carboxylate groups and magnetic nanoparticles as a promising adsorbent.

    PubMed

    Chi, Yue; Geng, Wangchang; Zhao, Liang; Yan, Xiao; Yuan, Qing; Li, Nan; Li, Xiaotian

    2012-03-01

    Highly ordered mesoporous carbon functionalized with carboxylate groups and magnetic nanoparticles has been successfully synthesized. By oxidative treatment using (NH(4))(2)S(2)O(8) and H(2)SO(4) mixed solution, numerous hydrophilic groups were created in the mesopores without destroying the ordered mesostructure of CMK-3. Through the in situ reduction in Fe(3+), magnetic nanoparticles were successfully introduced into the mesopores, resulting in the multifunctional mesoporous carbon Fe-CMK-3. The obtained hybrid carbon material possesses ordered mesostructure, high Brunauer-Emmett-Teller (BET) surface area up to 1013 m(2)/g, large pore volume of about 1.16 cm(3)/g, carboxylic surface, and excellent magnetic property. When used as an adsorbent, Fe-CMK-3 exhibits excellent performances for removing toxic organic compounds from waster-water, with a high adsorption capacity, an extremely rapid adsorption rate, and an easy magnetically separable process. In the case of requiring emergency removal of large amount of organic pollutants in aqueous, the hybrid carbon adsorbent would be an ideal choice.

  7. Removal of total organic carbon from sewage wastewater using poly(ethylenimine)-functionalized magnetic nanoparticles.

    PubMed

    Lakshmanan, Ramnath; Sanchez-Dominguez, Margarita; Matutes-Aquino, Jose A; Wennmalm, Stefan; Kuttuva Rajarao, Gunaratna

    2014-02-01

    The increased levels of organic carbon in sewage wastewater during recent years impose a great challenge to the existing wastewater treatment process (WWTP). Technological innovations are therefore sought that can reduce the release of organic carbon into lakes and seas. In the present study, magnetic nanoparticles (NPs) were synthesized, functionalized with poly(ethylenimine) (PEI), and characterized using TEM (transmission electron microscopy), X-ray diffraction (XRD), FTIR (Fourier transform infrared spectroscopy), CCS (confocal correlation spectroscopy), SICS (scattering interference correlation spectroscopy), magnetism studies, and thermogravimetric analysis (TGA). The removal of total organic carbon (TOC) and other contaminants using PEI-coated magnetic nanoparticles (PEI-NPs) was tested in wastewater obtained from the Hammarby Sjöstadsverk sewage plant, Sweden. The synthesized NPs were about 12 nm in diameter and showed a homogeneous particle size distribution in dispersion by TEM and CCS analyses, respectively. The magnetization curve reveals superparamagnetic behavior, and the NPs do not reach saturation because of surface anisotropy effects. A 50% reduction in TOC was obtained in 60 min when using 20 mg/L PEI-NPs in 0.5 L of wastewater. Along with TOC, other contaminants such as turbidity (89%), color (86%), total nitrogen (24%), and microbial content (90%) were also removed without significant changes in the mineral ion composition of wastewater. We conclude that the application of PEI-NPs has the potential to reduce the processing time, complexity, sludge production, and use of additional chemicals in the WWTP.

  8. Functionalized magnetic mesoporous silica nanoparticles for U removal from low and high pH groundwater.

    PubMed

    Li, Dien; Egodawatte, Shani; Kaplan, Daniel I; Larsen, Sarah C; Serkiz, Steven M; Seaman, John C

    2016-11-01

    U(VI) species display limited adsorption onto sediment minerals and synthetic sorbents in pH <4 or pH >8 groundwater. In this work, magnetic mesoporous silica nanoparticles (MMSNs) with magnetite nanoparticle cores were functionalized with various organic molecules using post-synthetic methods. The functionalized MMSNs were characterized using N2 adsorption-desorption isotherms, thermogravimetric analysis (TGA), transmission electron microscopy (TEM), (13)C cross polarization and magic angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectroscopy, and powder X-ray diffraction (XRD), which indicated that mesoporous silica (MCM-41) particles of 100-200nm formed around a core of magnetic iron oxide, and the functional groups were primarily grafted into the mesopores of ∼3.0nm in size. The functionalized MMSNs were effective for U removal from pH 3.5 and 9.6 artificial groundwater (AGW). Functionalized MMSNs removed U from the pH 3.5 AGW by as much as 6 orders of magnitude more than unfunctionalized nanoparticles or silica and had adsorption capacities as high as 38mg/g. They removed U from the pH 9.6 AGW as much as 4 orders of magnitude greater than silica and 2 orders of magnitude greater than the unfunctionalized nanoparticles with adsorption capacities as high as 133mg/g. These results provide an applied solution for treating U contamination that occurs at extreme pH environments and a scientific foundation for solving critical industrial issues related to environmental stewardship and nuclear power production.

  9. Functionalized magnetic mesoporous silica nanoparticles for U removal from low and high pH groundwater.

    PubMed

    Li, Dien; Egodawatte, Shani; Kaplan, Daniel I; Larsen, Sarah C; Serkiz, Steven M; Seaman, John C

    2016-11-01

    U(VI) species display limited adsorption onto sediment minerals and synthetic sorbents in pH <4 or pH >8 groundwater. In this work, magnetic mesoporous silica nanoparticles (MMSNs) with magnetite nanoparticle cores were functionalized with various organic molecules using post-synthetic methods. The functionalized MMSNs were characterized using N2 adsorption-desorption isotherms, thermogravimetric analysis (TGA), transmission electron microscopy (TEM), (13)C cross polarization and magic angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectroscopy, and powder X-ray diffraction (XRD), which indicated that mesoporous silica (MCM-41) particles of 100-200nm formed around a core of magnetic iron oxide, and the functional groups were primarily grafted into the mesopores of ∼3.0nm in size. The functionalized MMSNs were effective for U removal from pH 3.5 and 9.6 artificial groundwater (AGW). Functionalized MMSNs removed U from the pH 3.5 AGW by as much as 6 orders of magnitude more than unfunctionalized nanoparticles or silica and had adsorption capacities as high as 38mg/g. They removed U from the pH 9.6 AGW as much as 4 orders of magnitude greater than silica and 2 orders of magnitude greater than the unfunctionalized nanoparticles with adsorption capacities as high as 133mg/g. These results provide an applied solution for treating U contamination that occurs at extreme pH environments and a scientific foundation for solving critical industrial issues related to environmental stewardship and nuclear power production. PMID:27341378

  10. Ursolic Acid Inhibits Adipogenesis in 3T3-L1 Adipocytes through LKB1/AMPK Pathway

    PubMed Central

    He, Yonghan; Li, Ying; Zhao, Tiantian; Wang, Yanwen; Sun, Changhao

    2013-01-01

    Background Ursolic acid (UA) is a triterpenoid compound with multiple biological functions. This compound has recently been reported to possess an anti-obesity effect; however, the mechanisms are less understood. Objective As adipogenesis plays a critical role in obesity, the present study was conducted to investigate the effect of UA on adipogenesis and mechanisms of action in 3T3-L1 preadipocytes. Methods and Results The 3T3-L1 preadipocytes were induced to differentiate in the presence or absence of UA for 6 days. The cells were determined for proliferation, differentiation, fat accumulation as well as the protein expressions of molecular targets that regulate or are involved in fatty acid synthesis and oxidation. The results demonstrated that ursolic acid at concentrations ranging from 2.5 µM to 10 µM dose-dependently attenuated adipogenesis, accompanied by reduced protein expression of CCAAT element binding protein β (C/EBPβ), peroxisome proliferator-activated receptor γ (PPARγ), CCAAT element binding protein α (C/EBPα) and sterol regulatory element binding protein 1c (SREBP-1c), respectively. Ursolic acid increased the phosphorylation of acetyl-CoA carboxylase (ACC) and protein expression of carnitine palmitoyltransferase 1 (CPT1), but decreased protein expression of fatty acid synthase (FAS) and fatty acid-binding protein 4 (FABP4). Ursolic acid increased the phosphorylation of AMP-activated protein kinase (AMPK) and protein expression of (silent mating type information regulation 2, homolog) 1 (Sirt1). Further studies demonstrated that the anti-adipogenic effect of UA was reversed by the AMPK siRNA, but not by the Sirt1 inhibitor nicotinamide. Liver kinase B1 (LKB1), the upstream kinase of AMPK, was upregulated by UA. When LKB1 was silenced with siRNA or the inhibitor radicicol, the effect of UA on AMPK activation was diminished. Conclusions Ursolic acid inhibited 3T3-L1 preadipocyte differentiation and adipogenesis through the LKB1/AMPK pathway

  11. Locomotory behavior, contact inhibition, and pattern formation of 3T3 and polyoma virus-transformed 3T3 cells in culture

    PubMed Central

    Bell, PB

    1977-01-01

    The social behavior of 3T3 cells and their polynoma virus-transformed derivative (Py3T3 cells) was examined by time-lapse cinemicrography in order to determine what factors are responsible for the marked differences in the patterns formed by the two cell lines in culture. Contrary to expectations, both cell types have been found to exhibit contact inhibition of cell locomotion. Therefore, the tendency of 3T3 cells to form monolayers and of Py3T3 cells to form crisscrossed multilayers cannot be explained on the basis of the presence versus the absence of contact inhibition. Morevover, with the exception of cell division control, the social behavior of the two cell types is qualitively similar. Both exhibit cell underlapping and, after contact between lamelliopodia, both show inhibition of locomotory activity and adhesion formation. Neither cell type was observed to migrate over the surface of another cell. The two cell types do show quantitative differences in the frequency of underlapping, the frequency with which contact results in inhibition of locomotion, and the proportion of the cell margin that adheres to the substratum. The increased frequency pf Py3T3 underlapping is correlated with the reduced frequency of substratum adhesions, which in turn favors underlapping. On the basis of these observations, it is concluded that the differences in culture patterns are the result of differences in the shapes of the individual cells, such that underlapping, and hence crisscrossing, is favored in Py3T3 cell interactions and discouraged in 3T3 cells. PMID:198414

  12. Integrating Functional and Diffusion Magnetic Resonance Imaging for Analysis of Structure-Function Relationship in the Human Language Network

    PubMed Central

    Morgan, Victoria L.; Mishra, Arabinda; Newton, Allen T.; Gore, John C.; Ding, Zhaohua

    2009-01-01

    Background The capabilities of magnetic resonance imaging (MRI) to measure structural and functional connectivity in the human brain have motivated growing interest in characterizing the relationship between these measures in the distributed neural networks of the brain. In this study, we attempted an integration of structural and functional analyses of the human language circuits, including Wernicke's (WA), Broca's (BA) and supplementary motor area (SMA), using a combination of blood oxygen level dependent (BOLD) and diffusion tensor MRI. Methodology/Principal Findings Functional connectivity was measured by low frequency inter-regional correlations of BOLD MRI signals acquired in a resting steady-state, and structural connectivity was measured by using adaptive fiber tracking with diffusion tensor MRI data. The results showed that different language pathways exhibited different structural and functional connectivity, indicating varying levels of inter-dependence in processing across regions. Along the path between BA and SMA, the fibers tracked generally formed a single bundle and the mean radius of the bundle was positively correlated with functional connectivity. However, fractional anisotropy was found not to be correlated with functional connectivity along paths connecting either BA and SMA or BA and WA. Conclusions/Significance These findings suggest that structure-function relations in the human language circuits may involve a number of confounding factors that need to be addressed. Nevertheless, the insights gained from this work offers a useful guidance for continued studies that may provide a non-invasive means to evaluate brain network integrity in vivo for use in diagnosing and determining disease progression and recovery. PMID:19684850

  13. Recent advances in surface chemistry strategies for the fabrication of functional iron oxide based magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Turcheniuk, Kostiantyn; Tarasevych, Arkadii V.; Kukhar, Valeriy P.; Boukherroub, Rabah; Szunerits, Sabine

    2013-10-01

    The synthesis of superparamagnetic nanostructures, especially iron-oxide based nanoparticles (IONPs), with appropriate surface functional groups has been intensively researched for many high-technological applications, including high density data storage, biosensing and biomedicine. In medicine, IONPs are nowadays widely used as contrast agents for magnetic resonance imaging (MRI), in hyperthermia therapy, but are also exploited for drug and gene delivery, detoxification of biological fluids or immunoassays, as they are relatively non-toxic. The use of magnetic particles in vivo requires IONPs to have high magnetization values, diameters below 100 nm with overall narrow size distribution and long time stability in biological fluids. Due to the high surface energies of IONPs agglomeration over time is often encountered. It is thus of prime importance to modify their surface to prevent aggregation and to limit non-specific adsorption of biomolecules onto their surface. Such chemical modifications result in IONPs being well-dispersed and biocompatible, and allow for targeted delivery and specific interactions. The chemical nature of IONPs thus determines not only the overall size of the colloid, but also plays a significant role for in vivo and in vitro applications. This review discusses the different concepts currently used for the surface functionalization and coating of iron oxide nanoparticles. The diverse strategies for the covalent linking of drugs, proteins, enzymes, antibodies, and nucleotides will be discussed and the chemically relevant steps will be explained in detail.

  14. Succinate Functionalization of Hyperbranched Polyglycerol-Coated Magnetic Nanoparticles as a Draw Solute During Forward Osmosis.

    PubMed

    Yang, Hee-Man; Choi, Hye Min; Jang, Sung-Chan; Han, Myeong Jin; Seo, Bum-Kyoung; Moon, Jei-Kwon; Lee, Kune-Woo

    2015-10-01

    Hyperbranched polyglycerol-coated magnetic nanoparticles (SHPG-MNPs) were functionalized with succinate groups to form a draw solute for use in a forward osmosis (FO). After the one-step synthesis of hyperbranched polyglycerol-coated magnetic nanoparticles (HPG-MNPs), the polyglycerol groups on the surfaces of the HPG-MNPs were functionalized with succinic anhydride moieties. The resulting SHPG-MNPs showed no change of size and magnetic property compared with HPG-MNPs and displayed excellent dispersibility in water up to the concentration of 400 g/L. SHPG-MNPs solution showed higher osmotic pressure than that of HPG-MNPs solution due to the presence of surface carboxyl groups in SHPG-MNPs and could draw water from a feed solution across an FO membrane without any reverse draw solute leakage during FO process. Moreover, the water flux remained nearly constant over several SHPG-MNP darw solute regeneration cycles applied to the ultrafiltration (UF) process. The SHPG-MNPs demonstrate strong potential for use as a draw solute in FO processes.

  15. Highly Stable Amine Functionalized Iron Oxide Nanoparticles Designed for Magnetic Particle Imaging (MPI)

    PubMed Central

    Arami, Hamed; Krishnan, Kannan M.

    2014-01-01

    Magnetic particle imaging (MPI) is a promising medical imaging technology that uses iron oxide nanoparticles (NPs) as clinically safe tracers. The core and hydrodynamic size of these NPs determine the signal intensity and spatial resolution in MPI, whilst their monodispersity when preserved during the biomedical applications, generates a consistently high quality MPI image. Using an effective process to coat the synthesized NPs with amine terminated PEG molecules, we show by dynamic light scattering (DLS) that they are water-soluble with long-term stability in biological media such as phosphate buffered saline (PBS) and sodium bicarbonate buffers and Dulbecco’s modified Eagle medium (DMEM) enriched with 10% fetal bovine serum (FBS). Further, using magnetic particle spectroscopy (MPS), to measure the particle response function (PRF), defined as the derivative of the magnetization of the nanoparticles, we predict the MPI performance of these nanoparticles at a driving field frequency of 25 kHz. The MPS efficacy of the functionalized nanoparticles was also monitored over time, and both signal intensity and resolution remained unchanged even after seven days of incubation. This is attributed to the dominant contribution of the Néel relaxation mechanism of the monodisperse and highly stable nanoparticles, which was preserved through the incubation period. PMID:25554710

  16. Succinate Functionalization of Hyperbranched Polyglycerol-Coated Magnetic Nanoparticles as a Draw Solute During Forward Osmosis.

    PubMed

    Yang, Hee-Man; Choi, Hye Min; Jang, Sung-Chan; Han, Myeong Jin; Seo, Bum-Kyoung; Moon, Jei-Kwon; Lee, Kune-Woo

    2015-10-01

    Hyperbranched polyglycerol-coated magnetic nanoparticles (SHPG-MNPs) were functionalized with succinate groups to form a draw solute for use in a forward osmosis (FO). After the one-step synthesis of hyperbranched polyglycerol-coated magnetic nanoparticles (HPG-MNPs), the polyglycerol groups on the surfaces of the HPG-MNPs were functionalized with succinic anhydride moieties. The resulting SHPG-MNPs showed no change of size and magnetic property compared with HPG-MNPs and displayed excellent dispersibility in water up to the concentration of 400 g/L. SHPG-MNPs solution showed higher osmotic pressure than that of HPG-MNPs solution due to the presence of surface carboxyl groups in SHPG-MNPs and could draw water from a feed solution across an FO membrane without any reverse draw solute leakage during FO process. Moreover, the water flux remained nearly constant over several SHPG-MNP darw solute regeneration cycles applied to the ultrafiltration (UF) process. The SHPG-MNPs demonstrate strong potential for use as a draw solute in FO processes. PMID:26726503

  17. MULTIPASS MUON RLA RETURN ARCS BASED ON LINEAR COMBINED-FUNCTION MAGNETS

    SciTech Connect

    Vasiliy Morozov, Alex Bogacz, Yves Roblin, Kevin Beard

    2011-09-01

    Recirculating Linear Accelerators (RLA) are an efficient way of accelerating short-lived muons to the multi-GeV energies required for Neutrino Factories and TeV energies required for Muon Colliders. In this paper we present a design of a two-pass RLA return arc based on linear combined function magnets, in which both charge muons with momenta different by a factor of two are transported through the same string of magnets. The arc is composed of 60{sup o}-bending symmetric super cells allowing for a simple arc geometry closing. By adjusting the dipole and quadrupole components of the combined-function magnets, each super cell is designed to be achromatic and to have zero initial and final periodic orbit offsets for both muon momenta. Such a design provides a greater compactness than, for instance, an FFAG lattice with its regular alternating bends and is expected to possess a large dynamic aperture characteristic of linear-field lattices.

  18. Density-functional-theory calculations of matter in strong magnetic fields. I. Atoms and molecules

    NASA Astrophysics Data System (ADS)

    Medin, Zach; Lai, Dong

    2006-12-01

    We present calculations of the electronic structure of various atoms and molecules in strong magnetic fields ranging from B=1012Gto2×1015G , appropriate for radio pulsars and magnetars. For these field strengths, the magnetic forces on the electrons dominate over the Coulomb forces, and to a good approximation the electrons are confined to the ground Landau level. Our calculations are based on the density functional theory, and use a local magnetic exchange-correlation function which is tested to be reliable in the strong field regime. Numerical results of the ground-state energies are given for HN (up to N=10 ), HeN (up to N=8 ), CN (up to N=5 ), and FeN (up to N=3 ), as well as for various ionized atoms. Fitting formulae for the B dependence of the energies are also given. In general, as N increases, the binding energy per atom in a molecule, ∣EN∣/N , increases and approaches a constant value. For all the field strengths considered in this paper, hydrogen, helium, and carbon molecules are found to be bound relative to individual atoms (although for B less than a few ×1012G , carbon molecules are very weakly bound relative to individual atoms). Iron molecules are not bound at B≲1013G , but become energetically more favorable than individual atoms at larger field strengths.

  19. PML suppresses oncogenic transformation of NIH/3T3 cells by activated neu

    PubMed Central

    1995-01-01

    The chromosomal translocation t(15;17)(q22;q12) is a consistent feature of acute promyelocytic leukemia (APL) that results in the disruption of genes for the zinc finger transcription factor PML and the retinoic acid receptor alpha (RAR alpha). We have previously shown that PML is a growth suppressor and is able to suppress transformation of NIH/3T3 by activated neu oncogene. In the study presented here, the full-length PML cDNA was transfected into B104-1-1 cells (NIH/3T3 cells transformed by the activated neu oncogene) by retrovirally mediated gene transfer. We found that expression of PML could reverse phenotypes of B104-1-1 including morphology, contact-limiting properties, and growth rate in both transient-expression and stable transfectants. We also demonstrated that PML is able to suppress clonogenicity of B104-1-1 in soft agar assay and tumorigenicity in nude mice. These results strongly support our previous finding that PML is a transformation or growth suppressor. Our results further demonstrate that expression of PML in B104-1-1 cells has little effect on cell cycle distribution. Western blot analysis demonstrated that suppression of neu expression in B104-1- 1 by PML was insignificant in the transient transfection experiment but significant in the PML stable transfectants. This study suggests that PML may suppress neu expression and block signaling events associated with activated neu. This study supports our hypothesis that disruption of the normal function of PML, a growth or transformation suppressor, is a critical event in APL leukomogenesis. PMID:7759992

  20. Regulation of p53 in NIH3T3 mouse fibroblasts following hyperosmotic stress

    PubMed Central

    Lambert, Ian Henry; Enghoff, Maria Stine; Brandi, Marie-Luise; Hoffmann, Else Kay

    2015-01-01

    The aim of this project was to analyze the regulation of p53 expression in NIH3T3 fibroblasts under the influence of increasing hyperosmotic stress. Expression of p53 showed a biphasic response pattern in NIH3T3 cells under increasing osmotic stress (337 mOsm to 737 mOsm) with a maximum at 587 mOsm. Under isotonic conditions p53 expression increased after addition of the proteasome inhibitor MG132 indicating that cellular p53 levels in unperturbed cells is kept low by proteasomal degradation. However, under hypertonic conditions p53 synthesis as well as p53 degradation were significantly reduced and it is demonstrated that the increase in p53 expression observed when tonicity is increased from 337 to 587 mOsm reflects that degradation is more inhibited than synthesis, whereas the decrease in p53 expression at higher tonicities reflects that synthesis is more inhibited than degradation. The activity of the p53 regulating proteins p38 MAP kinase and the ubiquitin ligase MDM2 were studied as a function of increasing osmolarity. MDM2 protein expression was unchanged at all osmolarities, whereas MDM2 phosphorylation (Ser166) increased at osmolarities up to 537 mOsm and remained constant at higher osmolarities. Phosphorylation of p38 increased at osmolarities up to 687 mOsm which correlated with an increased phosphorylation of p53 (Ser15) and the decreased p53 degradation. Caspase-3 activity increased gradually with hypertonicity and at 737 mOsm both Caspase-3 activity and annexin V binding are high even though p53 expression and activity are low, indicating that initiation of apoptosis under severe hypertonic conditions is not strictly controlled by p53. PMID:26056062

  1. Regulation of p53 in NIH3T3 mouse fibroblasts following hyperosmotic stress.

    PubMed

    Lambert, Ian Henry; Enghoff, Maria Stine; Brandi, Marie-Luise; Hoffmann, Else Kay

    2015-06-01

    The aim of this project was to analyze the regulation of p53 expression in NIH3T3 fibroblasts under the influence of increasing hyperosmotic stress. Expression of p53 showed a biphasic response pattern in NIH3T3 cells under increasing osmotic stress (337 mOsm to 737 mOsm) with a maximum at 587 mOsm. Under isotonic conditions p53 expression increased after addition of the proteasome inhibitor MG132 indicating that cellular p53 levels in unperturbed cells is kept low by proteasomal degradation. However, under hypertonic conditions p53 synthesis as well as p53 degradation were significantly reduced and it is demonstrated that the increase in p53 expression observed when tonicity is increased from 337 to 587 mOsm reflects that degradation is more inhibited than synthesis, whereas the decrease in p53 expression at higher tonicities reflects that synthesis is more inhibited than degradation. The activity of the p53 regulating proteins p38 MAP kinase and the ubiquitin ligase MDM2 were studied as a function of increasing osmolarity. MDM2 protein expression was unchanged at all osmolarities, whereas MDM2 phosphorylation (Ser(166)) increased at osmolarities up to 537 mOsm and remained constant at higher osmolarities. Phosphorylation of p38 increased at osmolarities up to 687 mOsm which correlated with an increased phosphorylation of p53 (Ser(15)) and the decreased p53 degradation. Caspase-3 activity increased gradually with hypertonicity and at 737 mOsm both Caspase-3 activity and annexin V binding are high even though p53 expression and activity are low, indicating that initiation of apoptosis under severe hypertonic conditions is not strictly controlled by p53. PMID:26056062

  2. SiN-SiC nanofilm: A nano-functional ceramic with bipolar magnetic semiconducting character

    SciTech Connect

    Zhang, Jiahui; Li, Xingxing; Yang, Jinlong

    2014-04-28

    Nowadays, functional ceramics have been largely explored for application in various fields. However, magnetic functional ceramics for spintronics remain little studied. Here, we propose a nano-functional ceramic of sphalerite SiN-SiC nanofilm with intrinsic ferromagnetic order. Based on first principles calculations, the SiN-SiC nanofilm is found to be a ferromagnetic semiconductor with an indirect band gap of 1.71 eV. By mean field theory, the Curie temperature is estimated to be 304 K, close to room temperature. Furthermore, the valence band and conduction band states of the nanofilm exhibit inverse spin-polarization around the Fermi level. Thus, the SiN-SiC nanofilm is a typical bipolar magnetic semiconductor in which completely spin-polarized currents with reversible spin polarization can be created and controlled by applying a gate voltage. Such a nano-functional ceramic provides a possible route for electrical manipulation of carrier's spin orientation.

  3. Duplex communicable implanted antenna for magnetic direct feeding method: Functional electrical stimulation

    NASA Astrophysics Data System (ADS)

    Kato, Kentaro; Matsuki, Hidetoshi; Sato, Fumihiro; Satoh, Tadakuni; Handa, Nobuyasu

    2009-04-01

    Functional electrical stimulation (FES) is the therapy used for the rehabilitation of lost movement function by applying electrical stimulation (ES) to paralyzed extremities. To realize ES, we adapted the implanted direct feeding method (DFM). In this method, small implanted stimulators are placed under the skin at a depth of 10-20 mm and stimulus energy and signals for controlling devices are applied to them by a mounted system using magnetic coupling. This method has the merits of having no percutaneous points and high-precision stimulation. However, since the mounted system and implanted elements are separated, it is necessary to add feedback information from inside the body to confirm the system operation for safety therapy or to rehabilitate motor function smoothly. Satisfying both restrictions, we propose the magnetic connective dual resonance (MCDR) antenna, which has two resonance circuits. Adding the LC serial circuit to the LC parallel circuit gives the sending function. In this paper, we report the principle of the MCDR antenna and verify its duplex communication ability through communication experiment. This antenna enables DFM of FES to rehabilitate more complex movements.

  4. A portable single-sided magnet system for remote NMR measurements of pulmonary function

    PubMed Central

    Mikayel, Dabaghyan; Iga, Muradyan; James, Butler; Eric, Frederick; Feng, Zhou; Angelos, Kyriazis; Charles, Hardin; Samuel, Patz; Mirko, Hrovat

    2014-01-01

    In this work, we report initial results from a light-weight, low field magnetic resonance device designed to make relative pulmonary density measurements at the bedside. The development of this device necessarily involves special considerations for the magnet, RF and data acquisition schemes as well as a careful analysis of what is needed to provide useful information in the ICU. A homogeneous field region is created remotely from the surface of the magnet such that when the magnet is placed against the chest, an NMR signal is measured from a small volume in the lung. In order to achieve portability, one must trade off field strength and therefore spatial resolution. We report initial measurements from a ping-pong ball size region in the lung as a function of lung volume. As expected, we measured decreased signal at larger lung volumes since lung density decreases with increasing lung volume. Using a CPMG sequence with ΔTE=3.5 ms and a 20 echo train, a signal to noise ratio ~1100 was obtained from an 8.8mT planar magnet after signal averaging for 43 s. This is the first demonstration of NMR measurements made on a human lung with a light-weight planar NMR device. We argue that very low spatial resolution measurements of different lobar lung regions will provide useful diagnostic information for clinicians treating Acute Respiratory Distress Syndrome as clinicians want to avoid ventilator pressures that cause either lung over distension (too much pressure) or lung collapse (too little pressure). PMID:24953556

  5. Magnetic properties and paleointensities as function of depth in a Hawaiian lava flow

    NASA Astrophysics Data System (ADS)

    de Groot, Lennart V.; Dekkers, Mark J.; Visscher, Martijn; ter Maat, Geertje W.

    2014-04-01

    outcome of paleointensity experiments largely depends on the rock-magnetic properties of the samples. To assess the relation between volcanic emplacement processes and rock-magnetic properties, we sampled a vertical transect in a ˜6 m thick inflated lava flow at Hawaii, emplaced in ˜588 AD. Its rock-magnetic properties vary as function of distance from the flow top; the observations can be correlated to the typical cooling rate profile for such a flow. The top and to a lesser extent the bottom parts of the flow cooled faster and reveal a composition of ˜TM60 in which the magnetic remanence is carried by fine-grained titanomagnetites, relatively rich in titanium, with associated low Curie and unblocking temperatures. The titanomagnetite in the slower cooled central part of the flow is unmixed into the magnetite and ülvospinel end-members as evidenced by scanning electron microscope observation. The remanence is carried by coarse-grained magnetite lamella (˜TM0) with high Curie and unblocking temperatures. The calibrated pseudo-Thellier results that can be accepted yield an average paleointensity of 44.1 ± 2.4 μT. This is in good agreement with the paleointensity results obtained using the thermal IZZI-Thellier technique (41.6 ± 7.4 μT) and a recently proposed record for Hawaii. We therefore suggest that the chance of obtaining a reliable paleointensity from a particular cooling unit can be increased by sampling lavas at multiple levels at different distances from the top of the flow combined with careful preliminary testing of the rock-magnetic properties.

  6. Development of Magnetic Resonance-based Functional Imaging: The Past, the Present, and the Future.

    PubMed

    Matsumoto, Ken-Ichiro

    2016-01-01

    The term "theranostics" is a compound word combining "therapeutics" and "diagnostics". Discovery of the X-ray made an extraordinary contribution to the field of medical science. Development of computer science after World War II has been absolutely imperative for the development of medical imaging technology to date. The invention of X-ray computed tomography (CT) has revolutionized medical image diagnostic systems. Several functional imaging modalities emerged not only in the radiological field but also in magnetic resonance and ultrasonic fields. The fusion of three digital imaging techniques, MR Redox imaging, electron paramagnetic resonance (EPR) oxygen mapping, and hyperpolarized (13)C MRI techniques in the magnetic resonance field, contribute to the newly-termed theranostics. Future development of a suitable contrast agent for each imaging modality will be a key for the success of theranositics.

  7. Development of Magnetic Resonance-based Functional Imaging: The Past, the Present, and the Future.

    PubMed

    Matsumoto, Ken-Ichiro

    2016-01-01

    The term "theranostics" is a compound word combining "therapeutics" and "diagnostics". Discovery of the X-ray made an extraordinary contribution to the field of medical science. Development of computer science after World War II has been absolutely imperative for the development of medical imaging technology to date. The invention of X-ray computed tomography (CT) has revolutionized medical image diagnostic systems. Several functional imaging modalities emerged not only in the radiological field but also in magnetic resonance and ultrasonic fields. The fusion of three digital imaging techniques, MR Redox imaging, electron paramagnetic resonance (EPR) oxygen mapping, and hyperpolarized (13)C MRI techniques in the magnetic resonance field, contribute to the newly-termed theranostics. Future development of a suitable contrast agent for each imaging modality will be a key for the success of theranositics. PMID:27477720

  8. Bacterial inactivation using silver-coated magnetic nanoparticles as functional antimicrobial agents

    PubMed Central

    Wang, Lingyan; Luo, Jin; Shan, Shiyao; Crew, Elizabeth; Yin, Jun; Zhong, Chuan-Jian; Wallek, Brandi; Wong, Season

    2011-01-01

    The ability for silver nanoparticles to function as an antibacterial agent while being separable from the target fluids is important for bacterial inactivation in biological fluids. This report describes the analysis of the antimicrobial activities of silver-coated magnetic nanoparticles synthesized by wet chemical methods. The bacterial inactivation of several types of bacteria was analyzed, including Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) and Gram-negative bacteria (Pseudomonas aeruginosa, Enterobacter cloacae, and Escherichia coli). The results have demonstrated the viability of the silver-coated magnetic nanoparticles for achieving effective bacterial inactivation efficiency comparable to and better than silver nanoparticles conventionally used. The bacteria inactivation efficiency of our MZF@Ag nanoparticles were also determined for blood platelets samples, demonstrating the potential of utilization in inactivating bacterial growth in platelets prior to transfusion to ensure blood product safety, which also has important implications for enabling the capability of effective separation, delivery and targeting of the antibacterial agents. PMID:21999710

  9. Electronic and magnetic properties of yttrium-doped silicon carbide nanotubes: Density functional theory investigations

    SciTech Connect

    Khaira, Jobanpreet S.; Jain, Richa N.; Chakraborty, Brahmananda; Ramaniah, Lavanya M.

    2015-06-24

    The electronic structure of yttrium-doped Silicon Carbide Nanotubes has been theoretically investigated using first principles density functional theory (DFT). Yttrium atom is bonded strongly on the surface of the nanotube with a binding energy of 2.37 eV and prefers to stay on the hollow site at a distance of around 2.25 Å from the tube. The semi-conducting nanotube with chirality (4, 4) becomes half mettalic with a magnetic moment of 1.0 µ{sub B} due to influence of Y atom on the surface. There is strong hybridization between d orbital of Y with p orbital of Si and C causing a charge transfer from d orbital of the Y atom to the tube. The Fermi level is shifted towards higher energy with finite Density of States for only upspin channel making the system half metallic and magnetic which may have application in spintronic devices.

  10. Prostate Cancer: Value of Multiparametric MR Imaging at 3 T for Detection—Histopathologic Correlation1

    PubMed Central

    Turkbey, Baris; Pinto, Peter A.; Mani, Haresh; Bernardo, Marcelino; Pang, Yuxi; McKinney, Yolanda L.; Khurana, Kiranpreet; Ravizzini, Gregory C.; Albert, Paul S.; Merino, Maria J.

    2010-01-01

    Purpose: To determine utility of multiparametric imaging performed at 3 T for detection of prostate cancer by using T2-weighted magnetic resonance (MR) imaging, MR spectroscopy, and dynamic contrast material–enhanced MR imaging, with whole-mount pathologic findings as reference standard. Materials and Methods: This prospectively designed, HIPAA-compliant, single-institution study was approved by the local institutional review board. Seventy consecutive patients (mean age, 60.4 years; mean prostate-specific antigen level, 5.47 ng/mL [5.47 μg/L]; range, 1–19.9 ng/mL [1–19.9 μg/L]) were included; informed consent was obtained from each patient. All patients had biopsy-proved prostate cancer, with a median Gleason score of 7 (range, 6–9). Images were obtained by using a combination of six-channel cardiac and endorectal coils. MR imaging and pathologic findings were evaluated independently and blinded and then correlated with histopathologic findings by using side-by-side comparison. Analyses were conducted with a raw stringent approach and an alternative neighboring method, which accounted for surgical deformation, shrinkage, and nonuniform slicing factors in pathologic specimens. Generalized estimating equations (GEEs) were used to estimate the predictive value of region-specific, pathologically determined cancer for all three modalities. This approach accounts for the correlation among multiple regions in the same individual. Results: For T2-weighted MR imaging, sensitivity and specificity values obtained with stringent approach were 0.42 (95% confidence interval [CI]: 0.36, 0.47) and 0.83 (95% CI: 0.81, 0.86), and for the alternative neighboring approach, sensitivity and specificity values were 0.73 (95% CI: 0.67, 0.78) and 0.89 (95% CI: 0.85, 0.93), respectively. The combined diagnostic accuracy of T2-weighted MR imaging, dynamic contrast-enhanced MR imaging, and MR spectroscopy for peripheral zone tumors was examined by calculating their predictive value

  11. A guide to the metabolic pathways and function of metabolites observed in human brain 1H magnetic resonance spectra.

    PubMed

    Rae, Caroline D

    2014-01-01

    The current knowledge of the normal biochemistry of compounds that give rise to resonances in human brain proton magnetic resonance spectra measureable at readily available field strengths (i.e. ≤3 T) is reviewed. Molecules covered include myo- and scyllo-inositol, glycerophospho- and phospho-choline and choline, creatine and phosphocreatine, N-acetylaspartate, N-acetylaspartylglutamate, glutamate, glutamine, γ-aminobutyrate, glucose, glutathione and lactate. The factors which influence changes in the levels of these compounds are discussed. As most proton resonances in the brain at low field are derived from a combination of moieties whose biochemistry is complex and interrelated, an understanding of the mechanisms underlying why these species change is crucial to meaningful interpretation of human brain spectra.

  12. DEVELOPMENT OF SUPERCONDUCTING COMBINED FUNCTION MAGNETS FOR THE PROTON TRANSPORT LINE FOR THE J-PARC NEUTRINO EXPERIMENT.

    SciTech Connect

    NAKAMOTO, T.; AJIMA, Y.; FUJII, Y.; HIGASHI, N.; ICHIKAWA, A.; KIMURA, N.; KOBAYASHI, T.; MAKIDA, Y.; OGITSU, T.; OHHATA, H.; OKAMURA, T.; SASAKI, K.; ET AL.

    2005-05-16

    Superconducting combined function magnets will be utilized for the 50 GeV, 750 kW proton beam line for the J-PARC neutrino experiment. The magnet is designed to provide a dipole field of 2.6 T combined with a quadrupole field of 19 T/m in a coil aperture of 173.4 mm at a nominal current of 7345 A. Two full-scale prototype magnets to verify the magnet performance were successfully developed. The first prototype experienced no training quench during the excitation test and good field quality was confirmed.

  13. Neural Correlates of Symptom Dimensions in Pediatric Obsessive-Compulsive Disorder: A Functional Magnetic Resonance Imaging Study

    ERIC Educational Resources Information Center

    Gilbert, Andrew R.; Akkal, Dalila; Almeida, Jorge R. C.; Mataix-Cols, David; Kalas, Catherine; Devlin, Bernie; Birmaher, Boris; Phillips, Mary L.

    2009-01-01

    The use of functional magnetic resonance imaging on a group of pediatric subjects with obsessive compulsive disorder reveals that this group has reduced activity in neural regions underlying emotional processing, cognitive processing, and motor performance as compared to control subjects.

  14. Phase transitions, magnetism and surface adsorptions assessed by meta-GGA functionals and random phase approximation

    NASA Astrophysics Data System (ADS)

    Xiao, Bing

    investigated the electronic structures and magnetism of R-VO2 using exchange-correlation functionals of all five rungs on Jacob's ladder. Our calculations show that all semilocal functionals (LSDA, GGAs and meta-GGAs) and hybrid functionals (HSE06) stabilize the spin-polarized states (ferromagnetic and anti-ferromagnetic states) over non-magentic state, which are completely opposite to experimental observation. Suprisingly, LSDA gives the best energetic descriptions for magnetic and non-magnetic phases of R-VO2 among semilocal functionals and HSE06. Othwerwise, RPA calculations are highly dependent on the inputs in the spin polarized case. With PBE inputs, RPA also fails, giving lower energies for spin-polarized states than for the non-magnetic phase. Meawhile, the results are reversed using LSDA inputs. From the computed equilibrium cell volume, we observe the error cancellation in the exchange-correlation hole of most semilocal functionals in the spin-polarized calculations. LSDA and RPA do not fit to this picture. By analyzing the local magnetic moments of vanadium atoms, it is found that the magnetic property predicted from meta-GGA can be related to its exchange enhancement factor. The physisorption of a molecule on a transition metal surface is also another difficult problem in DFT because of the long-range van der Waals interactions. The recently developed MGGA_MS family of density functionals is able to capture a portion of intermediate range dispersion interactions. Therefore, we employed MGGA_MS2 to study the physisorption of CO2 on Pt (111) surface, and the results are compared to those of PBE, PBE+D2 and optB88-vdW methods. The computed binding curves comfirm that that MGGA_MS2 indeed captures the van der Waals interactions near the equilibrium binding distance, and the obtained binding distance is also in good agreement with PBE+D2 and optB88-vdW calculations. By computing the electron density difference map (EDDM), we find that the electron densities of CO2 and

  15. 26 CFR 1.702-3T - 4-Year spread (temporary).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 8 2014-04-01 2014-04-01 false 4-Year spread (temporary). 1.702-3T Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Partners and Partnerships § 1.702-3T 4-Year spread (temporary). (a... taxable year for the first taxable year beginning after December 31, 1986 (partnership's year of...

  16. 26 CFR 1.702-3T - 4-Year spread (temporary).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 8 2011-04-01 2011-04-01 false 4-Year spread (temporary). 1.702-3T Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Partners and Partnerships § 1.702-3T 4-Year spread (temporary). (a... taxable year for the first taxable year beginning after December 31, 1986 (partnership's year of...

  17. 26 CFR 1.702-3T - 4-Year spread (temporary).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 8 2010-04-01 2010-04-01 false 4-Year spread (temporary). 1.702-3T Section 1... (CONTINUED) INCOME TAXES Partners and Partnerships § 1.702-3T 4-Year spread (temporary). (a) Applicability... year for the first taxable year beginning after December 31, 1986 (partnership's year of change);...

  18. 26 CFR 1.702-3T - 4-Year spread (temporary).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 8 2012-04-01 2012-04-01 false 4-Year spread (temporary). 1.702-3T Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Partners and Partnerships § 1.702-3T 4-Year spread (temporary). (a... taxable year for the first taxable year beginning after December 31, 1986 (partnership's year of...

  19. 26 CFR 1.469-3T - Passive activity credit (temporary).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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  20. 26 CFR 1.469-3T - Passive activity credit (temporary).

    Code of Federal Regulations, 2012 CFR

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  1. 26 CFR 1.469-3T - Passive activity credit (temporary).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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  2. Neuroelectrical decomposition of spontaneous brain activity measured with functional magnetic resonance imaging.

    PubMed

    Liu, Zhongming; de Zwart, Jacco A; Chang, Catie; Duan, Qi; van Gelderen, Peter; Duyn, Jeff H

    2014-11-01

    Spontaneous activity in the human brain occurs in complex spatiotemporal patterns that may reflect functionally specialized neural networks. Here, we propose a subspace analysis method to elucidate large-scale networks by the joint analysis of electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) data. The new approach is based on the notion that the neuroelectrical activity underlying the fMRI signal may have EEG spectral features that report on regional neuronal dynamics and interregional interactions. Applying this approach to resting healthy adults, we indeed found characteristic spectral signatures in the EEG correlates of spontaneous fMRI signals at individual brain regions as well as the temporal synchronization among widely distributed regions. These spectral signatures not only allowed us to parcel the brain into clusters that resembled the brain's established functional subdivision, but also offered important clues for disentangling the involvement of individual regions in fMRI network activity.

  3. GPU-based parallel group ICA for functional magnetic resonance data.

    PubMed

    Jing, Yanshan; Zeng, Weiming; Wang, Nizhuan; Ren, Tianlong; Shi, Yingchao; Yin, Jun; Xu, Qi

    2015-04-01

    The goal of our study is to develop a fast parallel implementation of group independent component analysis (ICA) for functional magnetic resonance imaging (fMRI) data using graphics processing units (GPU). Though ICA has become a standard method to identify brain functional connectivity of the fMRI data, it is computationally intensive, especially has a huge cost for the group data analysis. GPU with higher parallel computation power and lower cost are used for general purpose computing, which could contribute to fMRI data analysis significantly. In this study, a parallel group ICA (PGICA) on GPU, mainly consisting of GPU-based PCA using SVD and Infomax-ICA, is presented. In comparison to the serial group ICA, the proposed method demonstrated both significant speedup with 6-11 times and comparable accuracy of functional networks in our experiments. This proposed method is expected to perform the real-time post-processing for fMRI data analysis.

  4. Visual object agnosia and pure word alexia: correlation of functional magnetic resonance imaging and lesion localization.

    PubMed

    Salvan, Carmen V; Ulmer, John L; DeYoe, Edgar A; Wascher, Thomas; Mathews, Vincent P; Lewis, James W; Prost, Robert W

    2004-01-01

    We present a case of a 64-year-old, right-handed female with a metastatic breast cancer lesion involving the left posterior inferior temporal lobe causing complete loss of the ability to recognize visually common objects and words. After her symptoms resolved on corticosteroid therapy, functional magnetic resonance imaging (fMRI) mapping demonstrated strong left-hemispheric dominance for word recognition and right-hemispheric dominance for object recognition. The case illustrates the relationships among ventral occipito-temporal cortical activation, lesion localization, and lesion-induced deficits of higher visual function. The relationship between hemispheric dominance determined by fMRI and risk of postoperative deficit depends on the specific visual function of interest.

  5. Independent Component Analysis Involving Autocorrelated Sources With an Application to Functional Magnetic Resonance Imaging

    PubMed Central

    Lee, Seonjoo; Shen, Haipeng; Truong, Young; Lewis, Mechelle; Huang, Xuemei

    2016-01-01

    Independent component analysis (ICA) is an effective data-driven method for blind source separation. It has been successfully applied to separate source signals of interest from their mixtures. Most existing ICA procedures are carried out by relying solely on the estimation of the marginal density functions, either parametrically or nonparametrically. In many applications, correlation structures within each source also play an important role besides the marginal distributions. One important example is functional magnetic resonance imaging (fMRI) analysis where the brain-function-related signals are temporally correlated. In this article, we consider a novel approach to ICA that fully exploits the correlation structures within the source signals. Specifically, we propose to estimate the spectral density functions of the source signals instead of their marginal density functions. This is made possible by virtue of the intrinsic relationship between the (unobserved) sources and the (observed) mixed signals. Our methodology is described and implemented using spectral density functions from frequently used time series models such as autoregressive moving average (ARMA) processes. The time series parameters and the mixing matrix are estimated via maximizing the Whittle likelihood function. We illustrate the performance of the proposed method through extensive simulation studies and a real fMRI application. The numerical results indicate that our approach outperforms several popular methods including the most widely used fastICA algorithm. This article has supplementary material online. PMID:27524847

  6. Copper Ferrocyanide-Functionalized Magnetic Adsorbents Using Polyethyleneimine Coated Fe3O4 Nanoparticles for the Removal of Radioactive Cesium.

    PubMed

    Yang, Hee-Man; Hong, Sang Bum; Cho, Yong Suk; Lee, Kune-Woo; Seo, Bum-Kyoung; Moon, Jei-Kwon

    2016-03-01

    Copper ferrocyanide-functionalized magnetic nano-adsorbents were successfully synthesized by electrostatic coating of citric acid coated Fe3O4 nanoparticles with polyethyleneimine, and immobilizing copper and ferrocyanide on the surfaces of polyethyleneimine-coated nanoparticles. Radioactive cesium (Cs) adsorption tests were conducted to investigate the effectiveness of the copper ferrocyanide-functionalized magnetic nano-adsorbents toward the removal of radioactive Cs. PMID:27455762

  7. Vectorial Slepian functions and the estimation of the crustal magnetic field

    NASA Astrophysics Data System (ADS)

    Plattner, Alain; Simons, Frederik

    2013-04-01

    Within the past two decades increasingly sophisticated magnetometry satellite missions have brought us data of ever improving quality and will reach a new pinnacle with the Swarm satellite mission to be launched in 2013. In order to make optimal use of this rich source of information for the lithospheric structure of Earth, and other planets, the computational algorithms used to obtain the crustal magnetic field from satellite data should be designed to take the specific properties of the data into account (e.g. their bandlimitation, their noise properties, the satellite altitude, their vectorial character). Ideally, the method should also be able to focus on chosen regions, be it as a means of regularization in a specifically targeted investigation or in order to discern between areas of intrinsically different properties of the field, such as for example crustal versus oceanic field. Such a merging of properties can be achieved using Slepian functions, a basis of bandlimited and spatially concentrated functions. The scalar version of Slepian functions has proven to be useful in a wide range of fields including geodesy, gravimetry, geomagnetism, and geodynamics. In order to make use of all three components of the vectorial data set we recently developed vectorial Slepian functions. In this presentation we combine the vectorial Slepian functions with the up- and downward continuation of vector fields to construct a fully vectorial estimation scheme for the regional crustal magnetic field from data at satellite altitude. We test our method with artificial data for different regions and bandlimits and compare different implementations of the method including regional concentration at satellite altitude, regional concentration on Earth's surface, and an estimation scheme employing vectorial Slepian functions that are constructed to ideally incorporate the defocusing effect due to altitude continuation.

  8. 3T3-L1 adipocytes display phenotypic characteristics of multiple adipocyte lineages

    PubMed Central

    Morrison, Shona; McGee, Sean L

    2015-01-01

    Differentiated 3T3-L1 adipocytes are a widely used in vitro model of white adipocytes. In addition to classical white and brown adipocytes that are derived from different cell lineages, beige adipocytes have also been identified, which have characteristics of both white and brown adipocytes. Here we show that 3T3-L1 adipocytes display features of multiple adipocytes lineages. While the gene expression profile and basal bioenergetics of 3T3-L1 adipocytes was typical of white adipocytes, they responded acutely to catecholamines by increasing oxygen consumption in an UCP1-dependent manner, and by increasing the expression of genes enriched in brown but not beige adipocytes. Chronic exposure to catecholamines exacerbated this phenotype. However, a beige adipocyte differentiation procedure did not induce a beige adipocyte phenotype in 3T3-L1 fibroblasts. These multiple lineage features should be considered when interpreting data from experiments utilizing 3T3-L1 adipocytes. PMID:26451286

  9. Design of covalently functionalized carbon nanotubes filled with metal oxide nanoparticles for imaging, therapy, and magnetic manipulation.

    PubMed

    Liu, Xiaojie; Marangon, Iris; Melinte, Georgian; Wilhelm, Claire; Ménard-Moyon, Cécilia; Pichon, Benoit P; Ersen, Ovidiu; Aubertin, Kelly; Baaziz, Walid; Pham-Huu, Cuong; Bégin-Colin, Sylvie; Bianco, Alberto; Gazeau, Florence; Bégin, Dominique

    2014-11-25

    Nanocomposites combining multiple functionalities in one single nano-object hold great promise for biomedical applications. In this work, carbon nanotubes (CNTs) were filled with ferrite nanoparticles (NPs) to develop the magnetic manipulation of the nanotubes and their theranostic applications. The challenges were both the filling of CNTs with a high amount of magnetic NPs and their functionalization to form biocompatible water suspensions. We propose here a filling process using CNTs as nanoreactors for high-yield in situ growth of ferrite NPs into the inner carbon cavity. At first, NPs were formed inside the nanotubes by thermal decomposition of an iron stearate precursor. A second filling step was then performed with iron or cobalt stearate precursors to enhance the encapsulation yield and block the formed NPs inside the tubes. Water suspensions were then obtained by addition of amino groups via the covalent functionalization of the external surface of the nanotubes. Microstructural and magnetic characterizations confirmed the confinement of NPs into the anisotropic structure of CNTs making them suitable for magnetic manipulations and MRI detection. Interactions of highly water-dispersible CNTs with tumor cells could be modulated by magnetic fields without toxicity, allowing control of their orientation within the cell and inducing submicron magnetic stirring. The magnetic properties were also used to quantify CNTs cellular uptake by measuring the cell magnetophoretic mobility. Finally, the photothermal ablation of tumor cells could be enhanced by magnetic stimulus, harnessing the hybrid properties of NP loaded-CNTs.

  10. Regulation of Na+-H+ exchange in normal NIH-3T3 cells and in NIH-3T3 cells expressing the ras oncogene

    SciTech Connect

    Owen, N.E.; Knapik, J.; Strebel, F.; Tarpley, W.G.; Gorman, R.R.

    1989-04-01

    Our laboratory and others have demonstrated that Na+-H+ exchange can be regulated by two different pathways; one that is mediated by an inositol trisphosphate-stimulated increase in intracellular calcium activity, and one that is mediated by an increase in protein kinase C activity. To determine whether one of these pathways is more important than the other, or whether one pathway is physiologically relevant, we employed normal NIH-3T3 cells (3T3 cells) and NIH-3T3 cells expressing the EJ human bladder ras oncogene (EJ cells). The EJ cells were chosen because they provide a genetic model that does not exhibit serum- or platelet-derived growth factor (PDGF)-stimulated inositol trisphosphate release or Ca2+ mobilization. It was found that serum- or PDGF-stimulated Na+-H+ exchange was more pronounced in EJ cells than in control 3T3 cells. As expected, serum- or PDGF-stimulated Na+-H+ exchange in 3T3 cells was inhibited by chelating intracellular Ca2+ with the intracellular Ca2+ chelator quin2, by the intracellular Ca2+ antagonist 8-(N,N-diethylamino)octyl 3,4,5-trimethoxybenzoate (TMB-8), and by the calmodulin antagonist trifluoperazine. In contrast, these agents did not inhibit serum- or PDGF-stimulated Na+-H+ exchange in EJ cells. Activators of protein kinase C (e.g., 1-oleoyl-2-acetylglycerol or biologically active phorbol esters) were found to stimulate Na+-H+ exchange in EJ cells to the same extent as serum. However, these agents were considerably less effective than serum in control 3T3 cells. Despite these findings, PDGF did not stimulate diacylglycerol levels in EJ cells.

  11. Evidence for correlations between distant intentionality and brain function in recipients: a functional magnetic resonance imaging analysis.

    PubMed

    Achterberg, Jeanne; Cooke, Karin; Richards, Todd; Standish, Leanna J; Kozak, Leila; Lake, James

    2005-12-01

    This study, using functional magnetic resonance imaging (fMRI) technology, demonstrated that distant intentionality (DI), defined as sending thoughts at a distance, is correlated with an activation of certain brain functions in the recipients. Eleven healers who espoused some form for connecting or healing at a distance were recruited from the island of Hawaii. Each healer selected a person with whom they felt a special connection as a recipient for DI. The recipient was placed in the MRI scanner and isolated from all forms of sensory contact from the healer. The healers sent forms of DI that related to their own healing practices at random 2-minute intervals that were unknown to the recipient. Significant differences between experimental (send) and control (no send) procedures were found (p = 0.000127). Areas activated during the experimental procedures included the anterior and middle cingulate area, precuneus, and frontal area. It was concluded that instructions to a healer to make an intentional connection with a sensory isolated person can be correlated to changes in brain function of that individual.

  12. Affinity capture using peptide-functionalized magnetic nanoparticles to target Staphylococcus aureus.

    PubMed

    Kuo, Fang-Yin; Lin, Wei-Lien; Chen, Yu-Chie

    2016-04-28

    Staphylococcus aureus, a commonly found pathogen, can cause food poisoning and infections. Thus, it is necessary to develop analytical methods for the rapid screening of S. aureus in suspicious samples. Magnetic nanoparticles (MNPs) are widely used as affinity probes to selectively enrich target species from complex samples because of their high specific surface area and magnetic properties. The MNP surface should be functionalized to have the capability to target specific species. We herein propose a straightforward method to functionalize aluminum oxide-coated iron oxide (Fe3O4@Al2O3) MNPs with the peptide HHHHHHDEEGLFVD (D). The peptide D was comprised of three domains: polyhistidine (H6) used as the linker, DEE added as the spacer, and GLFVD used for targeting S. aureus. D was immobilized on the surface of Fe3O4@Al2O3 MNPs through H6-Al chelation. Our results showed that the D-functionalized Fe3O4@Al2O3 MNPs (D-Fe3O4 MNPs) possess the capability to target S. aureus. The selective trapping experiments were conducted under microwave-heating for only 60 s, and sufficient bacterial cells were trapped by the MNPs to be identified by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). We demonstrated that the D-Fe3O4@Al2O3 MNPs combined with MALDI-MS can be used to rapidly characterize trace amounts of S. aureus in complex juice and egg samples. PMID:27087258

  13. DESIGN OF SUPERCONDUCTING COMBINED FUNCTION MAGNETS FOR THE 50 GEV PROTON BEAM LINE FOR THE J-PARC NEUTRINO EXPERIMENT.

    SciTech Connect

    WANDERER,P.; ET AL.

    2003-06-15

    Superconducting combined function magnets will be utilized for the 50GeV-750kW proton beam line for the J-PARC neutrino experiment and an R and D program has been launched at KEK. The magnet is designed to provide a combined function with a dipole field of 2.59 T and a quadrupole field of 18.7 T/m in a coil aperture of 173.4 mm. A single layer coil is proposed to reduce the fabrication cost and the coil arrangement in the 2-D cross-section results in left-right asymmetry. This paper reports the design study of the magnet.

  14. Combining Nuclear Magnetic Resonance Spectroscopy and Density Functional Theory Calculations to Characterize Carvedilol Polymorphs.

    PubMed

    Rezende, Carlos A; San Gil, Rosane A S; Borré, Leandro B; Pires, José Ricardo; Vaiss, Viviane S; Resende, Jackson A L C; Leitão, Alexandre A; De Alencastro, Ricardo B; Leal, Katia Z

    2016-09-01

    The experiments of carvedilol form II, form III, and hydrate by (13)C and (15)N cross-polarization magic-angle spinning (CP MAS) are reported. The GIPAW (gauge-including projector-augmented wave) method from DFT (density functional theory) calculations was used to simulate (13)C and (15)N chemical shifts. A very good agreement was found for the comparison between the global results of experimental and calculated nuclear magnetic resonance (NMR) chemical shifts for carvedilol polymorphs. This work aims a comprehensive understanding of carvedilol crystalline forms employing solution and solid-state NMR as well as DFT calculations.

  15. Investigating the emotional response to room acoustics: A functional magnetic resonance imaging study.

    PubMed

    Lawless, M S; Vigeant, M C

    2015-10-01

    While previous research has demonstrated the powerful influence of pleasant and unpleasant music on emotions, the present study utilizes functional magnetic resonance imaging (fMRI) to assess the positive and negative emotional responses as demonstrated in the brain when listening to music convolved with varying room acoustic conditions. During fMRI scans, subjects rated auralizations created in a simulated concert hall with varying reverberation times. The analysis detected activations in the dorsal striatum, a region associated with anticipation of reward, for two individuals for the highest rated stimulus, though no activations were found for regions associated with negative emotions in any subject.

  16. Temperature dependence of spin density in FeCo alloy: Magnetic response function

    NASA Astrophysics Data System (ADS)

    Petrillo, C.; Sacchetti, F.

    1994-02-01

    The magnetic structure factor of the equiatomic FeCo alloy has been measured in the disordered phase at 1000 K by polarized neutron diffraction. A comparison with the data collected in the ordered phase at room temperature [E. Di Fabrizio et al., Phys. Rev.B40, 9502 (1989)] shows marked variations that can be ascribed to the thermal motion of nuclei. From the complete set of data vs temperature, the experimental ion-electron linear response function has been deduced and compared to a theoretical Random Phase Approximation model.

  17. Nature versus nurture in ventral visual cortex: a functional magnetic resonance imaging study of twins.

    PubMed

    Polk, Thad A; Park, Joonkoo; Smith, Mason R; Park, Denise C

    2007-12-19

    Using functional magnetic resonance imaging, we estimated neural activity in twins to study genetic influences on the cortical response to categories of visual stimuli (faces, places, and pseudowords) that are known to elicit distinct patterns of activity in ventral visual cortex. The neural activity patterns in monozygotic twins were significantly more similar than in dizygotic twins for the face and place stimuli, but there was no effect of zygosity for pseudowords (or chairs, a control category). These results demonstrate that genetics play a significant role in determining the cortical response to faces and places, but play a significantly smaller role (if any) in the response to orthographic stimuli. PMID:18094229

  18. Optimizing the design and analysis of clinical functional magnetic resonance imaging research studies.

    PubMed

    Carter, Cameron S; Heckers, Stephan; Nichols, Thomas; Pine, Daniel S; Strother, Stephen

    2008-11-15

    With the widespread availability of functional magnetic resonance imaging (fMRI), there has been rapid progress in identifying neural correlates of cognition and emotion in the human brain. In conjunction with basic research studies, fMRI has been increasingly applied in clinical disorders, making it a central research tool in human psychopathology, psychopharmacology, and genetics. In the present article, we discuss a number of conceptual and methodological challenges that confront the implementation of fMRI in clinical and translational research, and we offer a set of recommendations intended to enhance the interpretability and reproducibility of results in clinical fMRI.

  19. Functional Magnetic Resonance Imaging of Motor Cortex: Hemispheric Asymmetry and Handedness

    NASA Astrophysics Data System (ADS)

    Kim, Seong-Gi; Ashe, James; Hendrich, Kristy; Ellermann, Jutta M.; Merkle, Hellmut; Ugurbil, Kamil; Georgopoulos, Apostolos P.

    1993-07-01

    A hemispheric asymmetry in the functional activation of the human motor cortex during contralateral (C) and ipsilateral (I) finger movements, especially in right-handed subjects, was documented with nuclear magnetic resonance imaging at high field strength (4 tesla). Whereas the right motor cortex was activated mostly during contralateral finger movements in both right-handed (C/I mean area of activation = 36.8) and left-handed (C/I = 29.9) subjects, the left motor cortex was activated substantially during ipsilateral movements in left-handed subjects (C/I = 5.4) and even more so in right-handed subjects (C/I = 1.3).

  20. Investigating the emotional response to room acoustics: A functional magnetic resonance imaging study.

    PubMed

    Lawless, M S; Vigeant, M C

    2015-10-01

    While previous research has demonstrated the powerful influence of pleasant and unpleasant music on emotions, the present study utilizes functional magnetic resonance imaging (fMRI) to assess the positive and negative emotional responses as demonstrated in the brain when listening to music convolved with varying room acoustic conditions. During fMRI scans, subjects rated auralizations created in a simulated concert hall with varying reverberation times. The analysis detected activations in the dorsal striatum, a region associated with anticipation of reward, for two individuals for the highest rated stimulus, though no activations were found for regions associated with negative emotions in any subject. PMID:26520354

  1. Vital functions of organisms in infra-low frequency magnetic fields 3. The embryogeny of mammals

    SciTech Connect

    Khizhenkov, P.K.; Bilobrov, V.M.; Zinkevich, I.I.; Zyablitsev, S.V.

    1994-10-01

    Results are presented of the experimental studies of the effect of variable (rotary) magnetic fields H at f = 6.5 Hz on the reproduction function of rats. It is shown that a pregnancy does not occur when mating takes place under the action of the field H. In the second quarter of pregnancy, the effect of the field is characterized by an increase of the mass of the body and of the internal organs of the new-born rats, among which, the growth of gemmae, spleen and of the thymus gland are particularly significant. The relative composition of the white blood cells changes as well.

  2. pH-responsive deoxyribonucleic acid capture/release by polydopamine functionalized magnetic nanoparticles.

    PubMed

    Wang, Yu; Ma, Xiangdong; Ding, Chun; Jia, Li

    2015-03-01

    Polydopamine functionalized magnetic nanoparticles (PDA@Fe3O4) were prepared and characterized by transmission electron microscopy, scanning electron microscopy, zeta potential and vibrating sample magnetometry. They were found to enable highly efficient capture of genomic deoxyribonucleic acid (DNA). The adsorption capacity of PDA@Fe3O4 for genomic DNA can reach 161 mg g(-1). The extraction protocol used aqueous solutions for DNA binding to and releasing from the surface of the magnetic particles based on the pH inducing the charge switch of amino and phenolic hydroxyl groups on PDA@Fe3O4. The extracted DNA with high quality (A260/A280=1.80) can be directly used as templates for polymerase chain reaction (PCR) followed by capillary electrophoresis (CE) analysis. None of the toxic chemical reagents and PCR inhibitors was used throughout the whole procedure. PDA@Fe3O4 based magnetic solid phase extraction (MSPE) method was superior to those using commercial kit and traditional phenol-chloroform extraction methods in yield of DNA. The developed PDA@Fe3O4 based MSPE-PCR-CE method was applied for simultaneous and fast detection of Listeria monocytogenes and Escherichia coli O157:H7 in milk. PMID:25682426

  3. Structural, electronic and magnetic effects of Al-doped niobium clusters: a density functional theory study.

    PubMed

    Wang, Huai-Qian; Li, Hui-Fang; Wang, Jia-Xian; Kuang, Xiao-Yu

    2012-07-01

    The application of the ab initio stochastic search procedure with Saunders "kick" method has been carried out for the elucidation of global minimum structures of a series of Al-doped clusters, Nb(n)Al (1 ≤ n ≤ 10). We have studied the structural characters, growth behaviors, electronic and magnetic properties of Nb(n)Al by the density functional theory calculations. Unlike the previous literature reported on Al-doped systems where ground state structures undergo a structural transition from the Al-capped frame to Al-encapsulated structure, we found that Al atom always occupies the surface of Nb(n)Al clusters and structural transition does not take place until n = 10. Note that the fragmentation proceeds preferably by the ejection of an aluminum atom other than niobium atom. According to the natural population analysis, charges always transfer from aluminum to niobium atoms. Furthermore, the magnetic moments of the Nb(n)Al clusters are mainly located on the 4d orbital of niobium atoms, and aluminum atom possesses very small magnetic moments.

  4. High-capacity adsorption of dissolved hexavalent chromium using amine-functionalized magnetic corn stalk composites.

    PubMed

    Song, Wen; Gao, Baoyu; Zhang, Tengge; Xu, Xing; Huang, Xin; Yu, Huan; Yue, Qinyan

    2015-08-01

    Easily separable amine-functionalized magnetic corn stalk composites (AF-MCS) were employed for effective adsorption and reduction of toxic hexavalent chromium [Cr(VI)] to nontoxic Cr(III). The saturated magnetization of AF-MCS reached 6.2emu/g, and as a result, it could be separated from aqueous solution by a magnetic process for its superparamagnetism. The studies of various factors influencing the sorption behavior indicated that the optimum AF-MCS dosage for Cr(VI) adsorption was 1g/L, and the maximum adsorption capacity was observed at pH 3.0. The chromium adsorption perfectly fitted the Langmuir isotherm model and pseudo second order kinetic model. Furthermore, characterization of AF-MCS was investigated by means of XRD, SEM, TEM, FT-IR, BET, VSM and XPS analysis to discuss the uptake mechanism. Basically, these results demonstrated that AF-MCS prepared in this work has shown its merit in effective removal of Cr(VI) and rapid separation from effluents simultaneously.

  5. H-1 Nuclear Magnetic Resonance Metabolomics Analysis Identifies Novel Urinary Biomarkers for Lung Function

    SciTech Connect

    MCClay, Joseph L.; Adkins, Daniel E.; Isern, Nancy G.; O'Connell, Thomas M.; Wooten, Jan B.; Zedler, Barbara K.; Dasika, Madhukar S.; Webb, B. T.; Webb-Robertson, Bobbie-Jo M.; Pounds, Joel G.; Murrelle, Edward L.; Leppert, Mark F.; van den Oord, Edwin J.

    2010-06-04

    Chronic obstructive pulmonary disease (COPD), characterized by chronic airflow limitation, is a serious and growing public health concern. The major environmental risk factor for COPD is tobacco smoking, but the biological mechanisms underlying COPD are not well understood. In this study, we used proton nuclear magnetic resonance (1H-NMR) spectroscopy to identify and quantify metabolites associated with lung function in COPD. Plasma and urine were collected from 197 adults with COPD and from 195 adults without COPD. Samples were assayed using a 600 MHz NMR spectrometer, and the resulting spectra were analyzed against quantitative spirometric measures of lung function. After correcting for false discoveries and adjusting for covariates (sex, age, smoking) several spectral regions in urine were found to be significantly associated with baseline lung function. These regions correspond to the metabolites trigonelline, hippurate and formate. Concentrations of each metabolite, standardized to urinary creatinine, were associated with baseline lung function (minimum p-value = 0.0002 for trigonelline). No significant associations were found with plasma metabolites. Two of the three urinary metabolites positively associated with baseline lung function, i.e. hippurate and formate, are often related to gut microflora. This suggests that the microbiome composition is variable between individuals with different lung function. Alternatively, the nature and origins of all three associated metabolites may reflect lifestyle differences affecting overall health. Our results will require replication and validation, but demonstrate the utility of NMR metabolomics as a screening tool for identifying novel biomarkers of lung disease or disease risk.

  6. Testing the Jacob's ladder of density functionals for electronic structure and magnetism of rutile VO2

    NASA Astrophysics Data System (ADS)

    Xiao, Bing; Sun, Jianwei; Ruzsinszky, Adrienn; Perdew, John P.

    2014-08-01

    We employ semilocal density functionals [local spin-density approximation (LSDA), Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA), and meta-GGAs)], LSDA plus Hubbard U (LSDA+U) theory, a nonlocal range-separated Heyd-Scuseria-Ernzerhof hybrid functional (HSE06), and the random-phase approximation (RPA) to assess their performances for the ground-state magnetism and electronic structure of a strongly correlated metal, rutile VO2. Using recent quantum Monte Carlo results as the benchmark, all tested semilocal and hybrid functionals as well as the RPA (with PBE inputs) predict the correct magnetic ground states for rutile VO2. The observed paramagnetism could arise from temperature-disordered local spin moments or from the thermal destruction of these moments. All semilocal functionals also give the correct ground-state metallicity for rutile VO2. However, in the ferromagnetic (FM) and antiferromagnetic (AFM) phases, LSDA+U and HSE06 incorrectly predict rutile VO2 to be a Mott-Hubbard insulator. For the computed electronic structures of FM and AFM phases, we find that the Tao-Perdew-Staroverov-Scuseria (TPSS) and revised TPSS (revTPSS) meta-GGAs give strong 2p-3d hybridizations, resulting in a depopulation of the 2p bands of O atoms, in comparison with other tested meta-GGAs. The regularized TPSS (regTPSS) and meta-GGAs made simple, i.e., MGGA_MS0 and MGGA_MS2, which are free of the spurious order-of-limits problem of TPSS and revTPSS, give electronic states close to those of the PBE GGA and LSDA. In comparison to experiment, semilocal functionals predict better equilibrium cell volumes for rutile VO2 in FM and AFM states than in the spin-unpolarized state. For meta-GGAs, a monotonic decrease of the exchange enhancement factor Fx(s,α) with α for small s, as in the MGGA_MS functionals, leads to large (probably too large) local magnetic moments in spin-polarized states.

  7. Reconstruction of 7T-Like Images From 3T MRI.

    PubMed

    Bahrami, Khosro; Shi, Feng; Zong, Xiaopeng; Shin, Hae Won; An, Hongyu; Shen, Dinggang

    2016-09-01

    In the recent MRI scanning, ultra-high-field (7T) MR imaging provides higher resolution and better tissue contrast compared to routine 3T MRI, which may help in more accurate and early brain diseases diagnosis. However, currently, 7T MRI scanners are more expensive and less available at clinical and research centers. These motivate us to propose a method for the reconstruction of images close to the quality of 7T MRI, called 7T-like images, from 3T MRI, to improve the quality in terms of resolution and contrast. By doing so, the post-processing tasks, such as tissue segmentation, can be done more accurately and brain tissues details can be seen with higher resolution and contrast. To do this, we have acquired a unique dataset which includes paired 3T and 7T images scanned from same subjects, and then propose a hierarchical reconstruction based on group sparsity in a novel multi-level Canonical Correlation Analysis (CCA) space, to improve the quality of 3T MR image to be 7T-like MRI. First, overlapping patches are extracted from the input 3T MR image. Then, by extracting the most similar patches from all the aligned 3T and 7T images in the training set, the paired 3T and 7T dictionaries are constructed for each patch. It is worth noting that, for the training, we use pairs of 3T and 7T MR images from each training subject. Then, we propose multi-level CCA to map the paired 3T and 7T patch sets to a common space to increase their correlations. In such space, each input 3T MRI patch is sparsely represented by the 3T dictionary and then the obtained sparse coefficients are used together with the corresponding 7T dictionary to reconstruct the 7T-like patch. Also, to have the structural consistency between adjacent patches, the group sparsity is employed. This reconstruction is performed with changing patch sizes in a hierarchical framework. Experiments have been done using 13 subjects with both 3T and 7T MR images. The results show that our method outperforms previous

  8. Reconstruction of 7T-Like Images From 3T MRI.

    PubMed

    Bahrami, Khosro; Shi, Feng; Zong, Xiaopeng; Shin, Hae Won; An, Hongyu; Shen, Dinggang

    2016-09-01

    In the recent MRI scanning, ultra-high-field (7T) MR imaging provides higher resolution and better tissue contrast compared to routine 3T MRI, which may help in more accurate and early brain diseases diagnosis. However, currently, 7T MRI scanners are more expensive and less available at clinical and research centers. These motivate us to propose a method for the reconstruction of images close to the quality of 7T MRI, called 7T-like images, from 3T MRI, to improve the quality in terms of resolution and contrast. By doing so, the post-processing tasks, such as tissue segmentation, can be done more accurately and brain tissues details can be seen with higher resolution and contrast. To do this, we have acquired a unique dataset which includes paired 3T and 7T images scanned from same subjects, and then propose a hierarchical reconstruction based on group sparsity in a novel multi-level Canonical Correlation Analysis (CCA) space, to improve the quality of 3T MR image to be 7T-like MRI. First, overlapping patches are extracted from the input 3T MR image. Then, by extracting the most similar patches from all the aligned 3T and 7T images in the training set, the paired 3T and 7T dictionaries are constructed for each patch. It is worth noting that, for the training, we use pairs of 3T and 7T MR images from each training subject. Then, we propose multi-level CCA to map the paired 3T and 7T patch sets to a common space to increase their correlations. In such space, each input 3T MRI patch is sparsely represented by the 3T dictionary and then the obtained sparse coefficients are used together with the corresponding 7T dictionary to reconstruct the 7T-like patch. Also, to have the structural consistency between adjacent patches, the group sparsity is employed. This reconstruction is performed with changing patch sizes in a hierarchical framework. Experiments have been done using 13 subjects with both 3T and 7T MR images. The results show that our method outperforms previous

  9. MAGNETS

    DOEpatents

    Hofacker, H.B.

    1958-09-23

    This patent relates to nmgnets used in a calutron and more particularly to means fur clamping an assembly of magnet coils and coil spacers into tightly assembled relation in a fluid-tight vessel. The magnet comprises windings made up of an assembly of alternate pan-cake type coils and spacers disposed in a fluid-tight vessel. At one end of the tank a plurality of clamping strips are held firmly against the assembly by adjustable bolts extending through the adjacent wall. The foregoing arrangement permits taking up any looseness which may develop in the assembly of coils and spacers.

  10. Detection of cannabinoid agonist evoked increase in BOLD contrast in rats using functional magnetic resonance imaging.

    PubMed

    Shah, Y B; Prior, M J W; Dixon, A L; Morris, P G; Marsden, C A

    2004-03-01

    BOLD-contrast functional magnetic resonance imaging (fMRI) was used to investigate the effects of the synthetic cannabinoid agonist HU210 on the rat brain in order to determine potential CNS sites of action for the functional effects of cannabinoids. After obtaining basal data, rats (n=8) were given the cannabinoid agonist HU210 (10 microg/kg i.v.) and volume data sets collected for 85 mins. Significant increases in functional BOLD activity were observed in specific brain regions including those important in pain (PAG), reward (VTA and accumbens) and motor function (striatum). In order to confirm cannabinoid receptor involvement in the HU210 evoked functional BOLD activity, rats (n=8) were pre-treated with the CB1 cannabinoid receptor antagonist SR141716A (100 microg/kg i.v.) prior to HU210. Pretreatment with SR141716A abolished all significant evoked HU210 functional BOLD activity. To exclude the involvement of potential systemic effects induced by the cannabinoid agonist administration on the observed evoked functional BOLD activity a separate experiment investigated the effect of HU210 (10 microg/kg i.v.) on mean arterial pressure and showed that HU210 had no significant effect on pressure under chloral hydrate anaesthesia. In summary, this study demonstrates that the cannabinoid agonist HU210 evokes a significant increase in BOLD functional activity in specific regions and that this was cannabinoid receptor mediated. Furthermore the study indicates the potential value of fMRI in rodents to delineate pharmacologically induced changes in regional brain function. PMID:14975693

  11. Suppressive Effects of Barley β-Glucans with Different Molecular Weight on 3T3-L1 Adipocyte Differentiation.

    PubMed

    Zhu, Yingying; Yao, Yang; Gao, Yue; Hu, Yibo; Shi, Zhenxing; Ren, Guixing

    2016-03-01

    In this study, 2 β-glucans with different molecular weight were prepared and purified from hull-less barley bran. The aim was to evaluate their effects on the differentiation of 3T3-L1 pre-adipocytes. Results showed that barley β-glucans inhibited the differentiation of 3T3-L1 pre-adipocytes induced by differentiation medium in a dose-dependent manner, the suppressive effect of high-molecular-weight barley β-glucans (552 kDa, BGH) was stronger (P < 0.05) than that of low-molecular-weight barley β-glucan (32 kDa, BGL), evidenced by the significantly decrease (P < 0.05) of Oil-red O staining and intracellular triglyceride content in the mature adipocytes. Besides, gene expression analysis and Western Blot analysis revealed that both BGH and BGL inhibited the mRNA and protein levels of adipogenesis related transcription factors peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT-enhancer-binding protein α (C/EBPα) which are principal regulators of adipogenesis. Furthermore, the mRNA and protein expression levels of PPARγ target genes in adipose tissue including adipocyte fatty acid binding protein (ap2), lipoprotein lipase (LPL), uncoupling protein-2 (UCP-2), and glucose-transporter 4 (Glut4) in 3T3-L1 cells was also markedly downregulated (P < 0.05). These findings were anticipated to help develop barley β-glucans based functional food for the management of obesity.

  12. A dual RF resonator system for high-field functional magnetic resonance imaging of small animals.

    PubMed

    Ludwig, R; Bodgdanov, G; King, J; Allard, A; Ferris, C F

    2004-01-30

    A new apparatus has been developed that integrates an animal restrainer arrangement for small animals with an actively tunable/detunable dual radio-frequency (RF) coil system for in vivo anatomical and functional magnetic resonance imaging of small animals at 4.7 T. The radio-frequency coil features an eight-element microstrip line configuration that, in conjunction with a segmented outer copper shield, forms a transversal electromagnetic (TEM) resonator structure. Matching and active tuning/detuning is achieved through fixed/variable capacitors and a PIN diode for each resonator element. These components along with radio-frequency chokes (RFCs) and blocking capacitors are placed on two printed circuit boards (PCBs) whose copper coated ground planes form the front and back of the volume coil and are therefore an integral part of the resonator structure. The magnetic resonance signal response is received with a dome-shaped single-loop surface coil that can be height-adjustable with respect to the animal's head. The conscious animal is immobilized through a mechanical arrangement that consists of a Plexiglas body tube and a head restrainer. This restrainer has a cylindrical holder with a mouthpiece and position screws to receive and restrain the head of the animal. The apparatus is intended to perform anatomical and functional magnetic resonance imaging in conscious animals such as mice, rats, hamsters, and marmosets. Cranial images acquired from fully conscious rats in a 4.7 T Bruker 40 cm bore animal scanner underscore the feasibility of this approach and bode well to extend this system to the imaging of other animals. PMID:14706710

  13. Low-Functioning Autism and Nonsyndromic Intellectual Disability: Magnetic Resonance Imaging (MRI) Findings.

    PubMed

    Erbetta, Alessandra; Bulgheroni, Sara; Contarino, Valeria Elisa; Chiapparini, Luisa; Esposito, Silvia; Annunziata, Silvia; Riva, Daria

    2015-10-01

    Previous neuroradiologic studies reported a high incidence of abnormalities in low-functioning autistic children. In this population, it is difficult to know which abnormality depends on autism itself and which is related to intellectual disability associated with autism. The aim of this study was to evaluate the frequency of neuroradiologic abnormalities in low-functioning autistic children compared to Intellectual Quotient and age-matched nonsyndromic children, using the same set of magnetic resonance imaging (MRI) sequences. MRI was rated as abnormal in 44% of autistic and 54% of children with intellectual disability. The main results were mega cisterna magna in autism and hypoplastic corpus callosum in intellectual disability. These abnormalities are morphologically visible signs of altered brain development. These findings, more frequent than expected, are not specific to the 2 conditions. Although MRI cannot be considered mandatory, it allows an in-depth clinical assessment in nonsyndromic intellectual-disabled and autistic children.

  14. Nuclear magnetic resonance spectroscopy for determining the functional content of organic aerosols: a review.

    PubMed

    Chalbot, Marie-Cecile G; Kavouras, Ilias G

    2014-08-01

    The knowledge deficit of organic aerosol (OA) composition has been identified as the most important factor limiting our understanding of the atmospheric fate and implications of aerosol. The efforts to chemically characterize OA include the increasing utilization of nuclear magnetic resonance spectroscopy (NMR). Since 1998, the functional composition of different types, sizes and fractions of OA has been studied with one-dimensional, two-dimensional and solid state proton and carbon-13 NMR. This led to the use of functional group ratios to reconcile the most important sources of OA, including secondary organic aerosol and initial source apportionment using positive matrix factorization. Future research efforts may be directed towards the optimization of experimental parameters, detailed NMR experiments and analysis by pattern recognition methods to identify the chemical components, determination of the NMR fingerprints of OA sources and solid state NMR to study the content of OA as a whole.

  15. [Event-related functional magnetic resonance imaging of cerebral pain processing].

    PubMed

    Meyer, H; Kleinböhl, D; Baudendistel, K; Bock, M; Trojan, J; Rabuffetti-Lehle, M; Hölzl, R; Schad, L R

    2001-01-01

    Neurofunctional magnetic resonance imaging (fMRI) offers the possibility to map cerebral activity non-invasively. The development of event-related techniques during the past years allows to study brain processes with high spatial and temporal resolution. Based on these techniques, EPI- and FLASH sequences were developed in this study, to investigate cerebral processing of experimental thermal pain stimulation. Phasic and tonic stimulation paradigms were developed with an MR-compatible contact thermode. Functional mapping of pain-relevant areas was performed with these paradigms, as well as a specification of the temporal characteristics of the activation. Further, a randomized paradigm with several stimulus intensities could differentiate graded functional responses, dependent on stimulus intensity in specific "regions-of-interest". In this design, randomizing the stimulus order reduced habituation effects, while continuous subjective magnitude estimation of the stimuli kept attention of subjects maximal. PMID:11487860

  16. Liquid Crystalline Block Copolymers with Brush Type Architecture: Toward Functional Membranes by Magnetic Field Alignment

    NASA Astrophysics Data System (ADS)

    Choo, Youngwoo; Gopinadhan, Manesh; Mahajan, Lalit; Kasi, Rajeswari; Osuji, Chinedum

    2015-03-01

    We introduce a novel liquid crystalline block copolymer with brush type architecture for membrane applications by magnetic field directed self-assembly. Ring-opening metathesis of n-alkyloxy cyanobiphenyl and polylactide (PLA) functionalized norbornene monomers provides efficient polymerization yielding low polydispersity block copolymers. The molecular weight of the PLA side chains, spacer length of the cyanobiphenyl mesogens are systematically varied to form well-ordered BCP morphologies at varying volume fractions. Interestingly, the system features morphology dependent anchoring condition where mesogens adopt planar anchoring on cylindrical interface while homeotropic anchoring was preferred on a planar block interface. The minority PLA domains from highly aligned materials can be readily degraded by hydrolysis to produce vertically aligned nanoporous polymer films which exhibit reversible thermal switching behavior. The polymers introduced here provide a versatile platform for scalable fabrication of aligned membranes and further functional materials based on such templates. This work was supported by NSF(CCMI-1246804).

  17. The impact of data preprocessing in traumatic brain injury detection using functional magnetic resonance imaging.

    PubMed

    Vergara, Victor M; Damaraju, Eswar; Mayer, Andrew B; Miller, Robyn; Cetin, Mustafa S; Calhoun, Vince

    2015-01-01

    Traumatic brain injury (TBI) can adversely affect a person's thinking, memory, personality and behavior. For this reason new and better biomarkers are being investigated. Resting state functional network connectivity (rsFNC) derived from functional magnetic resonance (fMRI) imaging is emerging as a possible biomarker. One of the main concerns with this technique is the appropriateness of methods used to correct for subject movement. In this work we used 50 mild TBI patients and matched healthy controls to explore the outcomes obtained from different fMRI data preprocessing. Results suggest that correction for motion variance before spatial smoothing is the best alternative. Following this preprocessing option a significant group difference was found between cerebellum and supplementary motor area/paracentral lobule. In this case the mTBI group exhibits an increase in rsFNC.

  18. Low-Functioning Autism and Nonsyndromic Intellectual Disability: Magnetic Resonance Imaging (MRI) Findings.

    PubMed

    Erbetta, Alessandra; Bulgheroni, Sara; Contarino, Valeria Elisa; Chiapparini, Luisa; Esposito, Silvia; Annunziata, Silvia; Riva, Daria

    2015-10-01

    Previous neuroradiologic studies reported a high incidence of abnormalities in low-functioning autistic children. In this population, it is difficult to know which abnormality depends on autism itself and which is related to intellectual disability associated with autism. The aim of this study was to evaluate the frequency of neuroradiologic abnormalities in low-functioning autistic children compared to Intellectual Quotient and age-matched nonsyndromic children, using the same set of magnetic resonance imaging (MRI) sequences. MRI was rated as abnormal in 44% of autistic and 54% of children with intellectual disability. The main results were mega cisterna magna in autism and hypoplastic corpus callosum in intellectual disability. These abnormalities are morphologically visible signs of altered brain development. These findings, more frequent than expected, are not specific to the 2 conditions. Although MRI cannot be considered mandatory, it allows an in-depth clinical assessment in nonsyndromic intellectual-disabled and autistic children. PMID:25895913

  19. Facile synthesis of boronic acid-functionalized magnetic carbon nanotubes for highly specific enrichment of glycopeptides

    NASA Astrophysics Data System (ADS)

    Ma, Rongna; Hu, Junjie; Cai, Zongwei; Ju, Huangxian

    2014-02-01

    A stepwise strategy was developed to synthesize boronic acid functionalized magnetic carbon nanotubes (MCNTs) for highly specific enrichment of glycopeptides. The MCNTs were synthesized by a solvothermal reaction of Fe3+ loaded on the acid-treated CNTs and modified with 1-pyrenebutanoic acid N-hydroxysuccinimidyl ester (PASE) to bind aminophenylboronic acid (APBA) via an amide reaction. The introduction of PASE could bridge the MCNT and APBA, suppress the nonspecific adsorption and reduce the steric hindrance among the bound molecules. Due to the excellent structure of the MCNTs, the functionalization of PASE and then APBA on MCNTs was quite simple, specific and effective. The glycopeptides enrichment and separation with a magnetic field could be achieved by their reversible covalent binding with the boronic group of APBA-MCNTs. The exceptionally large specific surface area and the high density of boronic acid groups of APBA-MCNTs resulted in rapid and highly efficient enrichment of glycopeptides, even in the presence of large amounts of interfering nonglycopeptides. The functional MCNTs possessed high selectivity for enrichment of 21 glycopeptides from the digest of horseradish peroxidase demonstrated by MALDI-TOF mass spectrometric analysis showing more glycopeptides detected than the usual 9 glycopeptides with commercially available APBA-agarose. The proposed system showed better specificity for glycopeptides even in the presence of non-glycopeptides with 50 times higher concentration. The boronic acid functionalized MCNTs provide a promising selective enrichment platform for precise glycoproteomic analysis.A stepwise strategy was developed to synthesize boronic acid functionalized magnetic carbon nanotubes (MCNTs) for highly specific enrichment of glycopeptides. The MCNTs were synthesized by a solvothermal reaction of Fe3+ loaded on the acid-treated CNTs and modified with 1-pyrenebutanoic acid N-hydroxysuccinimidyl ester (PASE) to bind aminophenylboronic acid

  20. The effects of antiepileptic drugs on cognitive functional magnetic resonance imaging

    PubMed Central

    Beltramini, Guilherme Coco; Cendes, Fernando

    2015-01-01

    The cognitive dysfunction caused by antiepileptic drugs (AEDs) has been extensively described, although the mechanisms underlying such collateral effects are still poorly understood. The combination of functional magnetic resonance imaging (fMRI) studies with pharmacological intervention (pharmaco-MRI or ph-MRI) offers the opportunity to investigate the effect of drugs such as AEDs on brain activity, including cognitive tasks. Here we review the studies that investigated the effects of AEDs [topiramate (TPM), lamotrigine (LMT), carbamazepine (CBZ), pregabalin (PGB), valproate (VPA) and levetiracetam (LEV)] on cognitive fMRI tasks. Despite the scarcity of fMRI studies focusing on the impact of AEDs on cognitive task, the results of recent work have provided important information about specific drug-related changes of brain function. PMID:25853082

  1. Magnetically induced behaviour of ferritin corpuscles in avian ears: can cuticulosomes function as magnetosomes?

    PubMed Central

    Jandacka, Petr; Burda, Hynek; Pistora, Jaromir

    2015-01-01

    Magnetoreception is an enigmatic, poorly understood sensory ability, described mainly on the basis of behavioural studies in animals of diverse taxa. Recently, corpuscles containing superparamagnetic iron-storage protein ferritin were found in the inner ear hair cells of birds, a predominantly single ferritin corpuscle per cell. It was suggested that these corpuscles might represent magnetosomes and function as magnetosensors. Here we determine ferritin low-field paramagnetic susceptibility to estimate its magnetically induced intracellular behaviour. Physical simulations show that ferritin corpuscles cannot be deformed or rotate in weak geomagnetic fields, and thus cannot provide magnetoreception via deformation of the cuticular plate. Furthermore, we reached an alternative hypothesis that ferritin corpuscle in avian ears may function as an intracellular electromagnetic oscillator. Such an oscillator would generate additional cellular electric potential related to normal cell conditions. Though the phenomenon seems to be weak, this effect deserves further analyses. PMID:25551148

  2. The impact of data preprocessing in traumatic brain injury detection using functional magnetic resonance imaging.

    PubMed

    Vergara, Victor M; Damaraju, Eswar; Mayer, Andrew B; Miller, Robyn; Cetin, Mustafa S; Calhoun, Vince

    2015-01-01

    Traumatic brain injury (TBI) can adversely affect a person's thinking, memory, personality and behavior. For this reason new and better biomarkers are being investigated. Resting state functional network connectivity (rsFNC) derived from functional magnetic resonance (fMRI) imaging is emerging as a possible biomarker. One of the main concerns with this technique is the appropriateness of methods used to correct for subject movement. In this work we used 50 mild TBI patients and matched healthy controls to explore the outcomes obtained from different fMRI data preprocessing. Results suggest that correction for motion variance before spatial smoothing is the best alternative. Following this preprocessing option a significant group difference was found between cerebellum and supplementary motor area/paracentral lobule. In this case the mTBI group exhibits an increase in rsFNC. PMID:26737520

  3. Active form Notch4 promotes the proliferation and differentiation of 3T3-L1 preadipocytes

    SciTech Connect

    Lai, Peng-Yeh; Tsai, Chong-Bin; Tseng, Min-Jen

    2013-01-18

    Highlights: ► Notch4IC modulates the ERK pathway and cell cycle to promote 3T3-L1 proliferation. ► Notch4IC facilitates 3T3-L1 differentiation by up-regulating proadipogenic genes. ► Notch4IC promotes proliferation during the early stage of 3T3-L1 adipogenesis. ► Notch4IC enhances differentiation during subsequent stages of 3T3-L1 adipogenesis. -- Abstract: Adipose tissue is composed of adipocytes, which differentiate from precursor cells in a process called adipogenesis. Many signal molecules are involved in the transcriptional control of adipogenesis, including the Notch pathway. Previous adipogenic studies of Notch have focused on Notch1 and HES1; however, the role of other Notch receptors in adipogenesis remains unclear. Q-RT-PCR analyses showed that the augmentation of Notch4 expression during the differentiation of 3T3-L1 preadipocytes was comparable to that of Notch1. To elucidate the role of Notch4 in adipogenesis, the human active form Notch4 (N4IC) was transiently transfected into 3T3-L1 cells. The expression of HES1, Hey1, C/EBPδ and PPARγ was up-regulated, and the expression of Pref-1, an adipogenic inhibitor, was down-regulated. To further characterize the effect of N4IC in adipogenesis, stable cells expressing human N4IC were established. The expression of N4IC promoted proliferation and enhanced differentiation of 3T3-L1 cells compared with those of control cells. These data suggest that N4IC promoted proliferation through modulating the ERK pathway and the cell cycle during the early stage of 3T3-L1 adipogenesis and facilitated differentiation through up-regulating adipogenic genes such as C/EBPα, PPARγ, aP2, LPL and HSL during the middle and late stages of 3T3-L1 adipogenesis.

  4. 3T MR Spectroscopy Reveals an Imbalance between Excitatory and Inhibitory Neurotransmitters in Amyotrophic Lateral Sclerosis

    PubMed Central

    Foerster, Bradley R.; Pomper, Martin G.; Callaghan, Brian C.; Petrou, Myria; Edden, Richard A.E.; Mohamed, Mona A.; Welsh, Robert C.; Carlos, Ruth C.; Barker, Peter B.; Feldman, Eva L.

    2015-01-01

    Objective To determine whether there are reductions in γ-aminobutyric acid (GABA) and elevations of glutamate + glutamine (Glx) levels in different brain regions of patients with amyotrophic lateral sclerosis (ALS) using proton magnetic resonance spectroscopy (1H-MRS). Design 3T short echo time and GABA-edited 1H-MRS centered on the left motor cortex and left subcortical white matter. Short echo time 1H-MRS was also performed centered on the pons. Data were analyzed using logistic regression, t-tests, and Pearson correlations. Post hoc analyses were performed to investigate differences between riluzole-naïve and riluzole-treated ALS patients. Participants Twenty-nine ALS patients and thirty age- and gender-matched healthy controls (HCs). Results ALS patients had significantly lower levels of GABA in the motor cortex compared to HCs (P<.01). ALS patients also had significantly lower levels of N-acetylaspartate in the motor cortex (P<.01), subcortical white matter (P<.05), and pons (P<.01) and higher levels of myo-inositol in the motor cortex (P<.001) and subcortical white matter (P<.01) compared to HCs. Compared to riluzole-treated ALS patients, riluzole-naïve ALS patients had higher levels of Glx in the motor cortex (P<.05) and pons (P<.01), higher levels of creatine in the motor cortex (P<.001) and subcortical white matter (P=.05), and higher levels of N-acetylaspartate in the motor cortex (P<.01). Conclusion There are reduced levels of GABA in the motor cortex of ALS patients. There are elevations of Glx in riluzole-naïve ALS patients compared to ALS riluzole-treated patients. These results point to an imbalance between excitatory and inhibitory neurotransmission, contributing to the pathogenesis of ALS. PMID:23797905

  5. Normal-appearing brain tissue analysis in radiologically isolated syndrome using 3 T MRI.

    PubMed

    Labiano-Fontcuberta, Andrés; Mato-Abad, Virginia; Álvarez-Linera, Juan; Hernández-Tamames, Juan Antonio; Martínez-Ginés, María Luisa; Aladro, Yolanda; Ayuso, Lucía; Domingo-Santos, Ángela; Benito-León, Julián

    2016-07-01

    To date, it remains largely unknown whether there is in radiologically isolated syndrome (RIS) brain damage beyond visible T2 white matter lesions. We used single- voxel proton magnetic resonance spectroscopy and diffusion tensor imaging (3 T MRI) to analyze normal-appearing brain tissue regions in 18 RIS patients and 18 matched healthy controls. T2-hyperintense lesion volumes and structural brain volumes were also measured. The absolute metabolite concentrations and ratios of total N-acetylaspartate+N-acetylaspartyl glutamate (NAA), choline-containing compounds, myoinositol, and glutamine-glutamate complex to creatine were calculated. Spectral analysis was performed by LCModel. Voxelwise morphometry analysis was performed to localize regions of brain tissue showing significant changes of fractional anisotropy or mean diffusivity. Compared with healthy controls, RIS patients did not show any significant differences in either the absolute concentration of NAA or NAA/Cr ratio in mid-parietal gray matter. A trend toward lower NAA concentrations (-3.35%) was observed among RIS patients with high risk for conversion to multiple sclerosis. No differences in the other metabolites or their ratios were observed. RIS patients showed lower fractional anisotropy only in clusters overlapping lesional areas, namely in the cingulate gyrus bilaterally and the frontal lobe subgyral bilaterally (P < 0.001). Normalized brain and cortical volumes were significantly lower in RIS patients than in controls (P = 0.01 and P = 0.03, respectively). Our results suggest that in RIS, global brain and cortical atrophy are not primarily driven by significant occult microstructural normal appearing brain damage. Longitudinal MRI studies are needed to better understand the pathological processes underlying this novel entity. PMID:27399108

  6. Assembly of cyanometalate-functionalized phosphotungstates with magnetic properties and bifunctional electrocatalytic activities.

    PubMed

    Wang, Ya; Sun, Ming-Hui; Li, Feng-Yan; Sun, Zhi-Xia; Xu, Lin

    2015-03-14

    Two cyanometalate-functionalized heteropolytungstates (C4H10ON)23[HN(CH2CH2OH)3]11H[Fe(III()CN)6(α2-P2W17O61Ni(II))4]·31H2O (1) and (C4H10ON)23[HN(CH2CH2OH)3]10H2[Fe(III)(CN)6(α2-P2W17O61Co(II))4]·27H2O (2) (C4H10ON = morpholine, HN(CH2CH2OH)3 = triethanol amine) have been successfully synthesized in aqueous solution under conventional reaction conditions, which demonstrated that it is a successful strategy to incorporate the cyanometalate fragment into lacunary heteropolytungstates. These polyanions were characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis, thermogravimetric analysis, magnetic studies, and electrochemistry. Interestingly, the electrochemical studies have shown that the two complexes have bifunctional electrocatalytic activities towards not only the reduction of potassium iodate (KIO3) ascribed to the function of POM, but also the oxidation of the biological molecule ascorbic acid (AA) ascribed to the Fe-center in [M(II)4Fe(III)(CN)6](5+). Significantly, the magnetic investigations demonstrate the presence of ferromagnetic exchange interactions in 1 (Ni4Fe) and antiferromagnetic interactions in 2 (Co4Fe).

  7. Magnetic hydrogels from alkyne/cobalt carbonyl-functionalized ABA triblock copolymers

    DOE PAGES

    Jiang, Bingyin; Hom, Wendy L.; Chen, Xianyin; Yu, Pengqing; Pavelka, Laura C.; Kisslinger, Kim; Parise, John B.; Bhatia, Surita R.; Grubbs, Robert B.

    2016-03-09

    A series of alkyne-functionalized poly(4-(phenylethynyl)styrene)-block-poly(ethylene oxide)-block-poly(4-(phenylethynyl)styrene) (PPES-b-PEO-b-PPES) ABA triblock copolymers was synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization. PESn[Co2(CO)6]x-EO800-PESn[Co2(CO)6]x ABA triblock copolymer/cobalt adducts (10–67 wt % PEO) were subsequently prepared by reaction of the alkyne-functionalized PPES block with Co2(CO)8 and their phase behavior was studied by TEM. Heating triblock copolymer/cobalt carbonyl adducts at 120 °C led to cross-linking of the PPES/Co domains and the formation of magnetic cobalt nanoparticles within the PPES/Co domains. Magnetic hydrogels could be prepared by swelling the PEO domains of the cross-linked materials with water. Furthermore, swelling tests, rheological studies and actuation tests demonstrated thatmore » the water capacity and modulus of the hydrogels were dependent upon the composition of the block copolymer precursors.« less

  8. Functionalized magnetic nanoparticles for the decontamination of water polluted with cesium

    NASA Astrophysics Data System (ADS)

    Helal, Ahmed S.; Decorse, Philippe; Perruchot, Christian; Novak, Sophie; Lion, Claude; Ammar, Souad; El Hage Chahine, Jean-Michel; Hémadi, Miryana

    2016-05-01

    Magnetic nanoparticles are attracting considerable interest because of their potential applications in practically all fields of science and technology, including the removal of heavy metals from contaminated waters. It is, therefore, of great importance to adapt the surfaces of these nanoparticles according to the application. In this work advanced nanoparticles (NPs) with well-tailored surface functionalities were synthesized using the polyol method. The efficiency of a chelating agent, succinyl-β-cyclodextrin (SBCD), was first investigated spectrophotometrically and by Isothermal Titration Calorimetry (ITC). SBCD was then grafted onto nanoparticles previously functionalized with 3-aminopropyl triethoxsilane (NP-APTES). The resulting NP-SBCD system was then incubated with a solution of cesium. After magnetic separation, the solid residue was removed from the supernatant and characterized by X-Ray Photoelectron spectrometry (XPS), X-Ray Fluorescence spectrometry (XRF) and Superconducting QUantum Interference Device (SQUID) magnetometry. These characterizations show the presence of cesium in the solid residue, which indicates Cs uptake by the NP-SBCD system. This nanohybrid system constitutes a promising model for heavy metal decontamination.

  9. Lateral flow biosensor for multiplex detection of nitrofuran metabolites based on functionalized magnetic beads.

    PubMed

    Lu, Xuewen; Liang, Xiaoling; Dong, Jianghong; Fang, Zhiyuan; Zeng, Lingwen

    2016-09-01

    The use of potential mutagenic nitrofuran antibiotic in food animal production has been banned world-wide. Common methods for nitrofuran detection involve complex extraction procedures. In the present study, magnetic beads functionalized with antibody against nitrofuran derivative were used as both the extraction and color developing media in lateral flow biosensor. Derivatization reagent carboxybenzaldehyde is firstly modified with ractopamine. After reaction with nitrofuran metabolites, the resultant molecule has two functional groups: the metabolite moiety and the ractopamine moiety. Metabolite moiety is captured by the antibody that is coated on magnetic beads. This duplex is then loaded onto biosensor and ractopamine moiety is further captured by the antibody immobilized on the test zone of nitrocellulose membrane. Without tedious organic reagent-based extraction procedure, this biosensor was capable of visually detecting four metabolites simultaneously with a detection limit of 0.1 μg/L. No cross-reactivity was observed in the presence of 50 μg/L interferential components. Graphical abstract Derivatization of nitrofuran metabolites (AHD, AOZ, SEM, or AMOZ) and LFA detection of the derivative products. PMID:27438720

  10. Magnetically-tunable spin-selective positioning of wave functions in asymmetric semiconductor quantum structures

    NASA Astrophysics Data System (ADS)

    Lee, S.; Titova, L. V.; Furdyna, Jacek K.; Dobrowolska, M.

    2000-03-01

    It has been recently reported that the properties of self-organized CdSe quantum dots (QDs) on ZnSe change significantly when they are grown on ZnMnSe spacers separating CdSe form ZnSe.[1] To explore this effect futher, we have prepared a series of samples by depositing one monolayer (ML) of CdSe on ZnMnSe spacer layers of different thickness and different Mn concentration. The system is then capped with ZnSe. The band structure for this geometry results in an asymmetric quantum structure, where the 1 ML thick CdSe acts as a "well" between barriers comprised of ZnSe on side, and ZnMnSe on the other. When a magnetic field is applied, the Zeeman splitting of the band edges in ZnMnSe spacer moves the position of the wave function toward or away from the spacer, depending on spin orientation. Such spin-selective repositioning of the wave functions is fully confirmed by magnetic field dependence of ground state exciton transitions observed in PL. This work was supported by NSF Grant DMR 9705064. [1]C.S. Kim et.al., 9th International conference on II-VI compounds, Kyoto, Nov. 1-5, 1999.

  11. Covalent Immobilization of Bacillus licheniformis γ-Glutamyl Transpeptidase on Aldehyde-Functionalized Magnetic Nanoparticles

    PubMed Central

    Chen, Yi-Yu; Tsai, Ming-Gen; Chi, Meng-Chun; Wang, Tzu-Fan; Lin, Long-Liu

    2013-01-01

    This work presents the synthesis and use of surface-modified iron oxide nanoparticles for the covalent immobilization of Bacillus licheniformis γ-glutamyl transpeptidase (BlGGT). Magnetic nanoparticles were prepared by an alkaline solution of divalent and trivalent iron ions, and they were subsequently treated with 3-aminopropyltriethoxysilane (APES) to obtain the aminosilane-coated nanoparticles. The functional group on the particle surface and the amino group of BlGGT was then cross-linked using glutaraldehyde as the coupling reagent. The loading capacity of the prepared nanoparticles for BlGGT was 34.2 mg/g support, corresponding to 52.4% recovery of the initial activity. Monographs of transmission electron microscopy revealed that the synthesized nanoparticles had a mean diameter of 15.1 ± 3.7 nm, and the covalent cross-linking of the enzyme did not significantly change their particle size. Fourier transform infrared spectroscopy confirmed the immobilization of BlGGT on the magnetic nanoparticles. The chemical and kinetic behaviors of immobilized BlGGT are mostly consistent with those of the free enzyme. The immobilized enzyme could be recycled ten times with 36.2% retention of the initial activity and had a comparable stability respective to free enzyme during the storage period of 30 days. Collectively, the straightforward synthesis of aldehyde-functionalized nanoparticles and the efficiency of enzyme immobilization offer wide perspectives for the practical use of surface-bound BlGGT. PMID:23443161

  12. Controlled surface functionality of magnetic nanoparticles by layer-by-layer assembled nano-films

    NASA Astrophysics Data System (ADS)

    Choi, Daheui; Son, Boram; Park, Tai Hyun; Hong, Jinkee

    2015-04-01

    Over the past several years, the preparation of functionalized nanoparticles has been aggressively pursued in order to develop desired structures, compositions, and structural order. Among the various nanoparticles, iron oxide magnetic nanoparticles (MNPs) have shown great promise because the material generated using these MNPs can be used in a variety of biomedical applications and possible bioactive functionalities. In this study, we report the development of various functionalized MNPs (F-MNPs) generated using the layer-by-layer (LbL) self-assembly method. To provide broad functional opportunities, we fabricated F-MNP bio-toolbox by using three different materials: synthetic polymers, natural polymers, and carbon materials. Each of these F-MNPs displays distinct properties, such as enhanced thickness or unique morphologies. In an effort to explore their biomedical applications, we generated basic fibroblast growth factor (bFGF)-loaded F-MNPs. The bFGF-loaded F-MNPs exhibited different release mechanisms and loading amounts, depending on the film material and composition order. Moreover, bFGF-loaded F-MNPs displayed higher biocompatibility and possessed superior proliferation properties than the bare MNPs and pure bFGF, respectively. We conclude that by simply optimizing the building materials and the nanoparticle's film composition, MNPs exhibiting various bioactive properties can be generated.Over the past several years, the preparation of functionalized nanoparticles has been aggressively pursued in order to develop desired structures, compositions, and structural order. Among the various nanoparticles, iron oxide magnetic nanoparticles (MNPs) have shown great promise because the material generated using these MNPs can be used in a variety of biomedical applications and possible bioactive functionalities. In this study, we report the development of various functionalized MNPs (F-MNPs) generated using the layer-by-layer (LbL) self-assembly method. To provide

  13. Effect of the double-counting functional on the electronic and magnetic properties of half-metallic magnets using the GGA+U method

    NASA Astrophysics Data System (ADS)

    Tsirogiannis, Christos; Galanakis, Iosif

    2015-11-01

    Methods based on the combination of the usual density functional theory (DFT) codes with the Hubbard models are widely used to investigate the properties of strongly correlated materials. Using first-principle calculations we study the electronic and magnetic properties of 20 half-metallic magnets performing self-consistent GGA+U calculations using both the atomic-limit (AL) and around-mean-field (AMF) functionals for the double counting term, used to subtract the correlation part from the DFT total energy, and compare these results to the usual generalized-gradient-approximation (GGA) calculations. Overall the use of AMF produces results similar to the GGA calculations. On the other hand the effect of AL is diversified depending on the studied material. In general the AL functional produces a stronger tendency towards magnetism leading in some cases to unphysical electronic and magnetic properties. Thus the choice of the adequate double-counting functional is crucial for the results obtained using the GGA+U method.

  14. Functional imaging as an indicator of diagnostic information in cardiac magnetic-resonance images

    NASA Astrophysics Data System (ADS)

    Klingler, Joseph W.; Andrews, Lee T.; Begeman, Michael S.; Zeiss, Jacob; Leighton, Richard F.

    1990-08-01

    Magnetic Resonance (MR) images of the human heart provide three dimensional geometric information about the location of cardiac structures throughout the cardiac cycle. Analysis of this four dimensional data set allows detection of abnormal cardiac function related to the presence of coronary artery disease. To assist in this analysis, quantitative measurements of cardiac performance are made from the MR data including ejection fractions, regional wall motion and myocardial wall thickening. Analysis of cardiac performance provided by quantitative analysis of MR data can be aided by computer graphics presentation techniques. Two and three dimensional functional images are computed to indicate regions of abnormality based on the previous methods. The two dimensional images are created using color graphics overlays on the original MR image to represent performance. Polygon surface modeling techniques are used to represent data which is three dimensional, such as blood pool volumes. The surface of these images are color encoded by regional ejection fraction, wall motion or wall thickening. A functional image sequence is constructed at each phase of the cardiac cycle and displayed as a movie loop for review by the physician. Selection of a region on the functional image allows visual interpretation of the original MR images, graphical plots of cardiac function and tabular results. Color encoding is based on absolute measurements and comparison to standard normal templates of cardiac performance.

  15. Association between the XRCC3 T241M polymorphism and risk of cancer: evidence from 157 case-control studies.

    PubMed

    He, Xiao-Feng; Wei, Wu; Li, Jia-Lin; Shen, Xu-Liang; Ding, Da-peng; Wang, Su-Lan; Liu, Zhi-Zhong; Qin, Jiang-Bo; Wu, Li-Xia; Xie, Dao-Lin

    2013-07-01

    The T241M polymorphism in the X-ray cross-complementing group 3 (XRCC3) had been implicated in cancer susceptibility. The previous published data on the association between XRCC3 T241M polymorphism and cancer risk remained controversial. Hence, we performed a meta-analysis to investigate the association between cancer susceptibility and XRCC3 T241M (61,861 cases and 84,584 controls from 157 studies) polymorphism in different inheritance models. We used odds ratios with 95% confidence intervals to assess the strength of the association. Overall, significantly increased cancer risk was observed in any genetic model (dominant model: odds ration [OR]=1.07, 95% confidence interval [CI]=1.00-1.13; recessive model: OR=1.15, 95% CI=1.08-1.23; additive model: OR=1.17, 95% CI=1.08-1.28) when all eligible studies were pooled into the meta-analysis. In further stratified and sensitivity analyses, the elevated risk remained for subgroups of bladder cancer and breast cancer, especially in Caucasians. In addition, significantly decreased lung cancer risk was also observed. In summary, this meta-analysis suggests the participation of XRCC3 T241M in the susceptibility for bladder cancer and breast cancer, especially in Caucasians, and XRCC3 T241M polymorphism is associated with decreased lung cancer risk. Moreover, our work also points out the importance of new studies for T241M association in some cancer types, such as gastric cancer, colorectal cancer, and melanoma skin cancer, where at least some of the covariates responsible for heterogeneity could be controlled, to obtain a more conclusive understanding about the function of the XRCC3 polymorphism in cancer development. PMID:23562721

  16. Comparison of three magnetic bead surface functionalities for RNA extraction and detection.

    PubMed

    Adams, Nicholas M; Bordelon, Hali; Wang, Kwo-Kwang A; Albert, Laura E; Wright, David W; Haselton, Frederick R

    2015-03-25

    Magnetic beads are convenient for extracting nucleic acid biomarkers from biological samples prior to molecular detection. These beads are available with a variety of surface functionalities designed to capture particular subsets of RNA. We hypothesized that bead surface functionality affects binding kinetics, processing simplicity, and compatibility with molecular detection strategies. In this report, three magnetic bead surface chemistries designed to bind nucleic acids, silica, oligo (dT), and a specific oligonucleotide sequence were evaluated. Commercially available silica-coated and oligo (dT) beads, as well as beads functionalized with oligonucleotides complementary to respiratory syncytial virus (RSV) nucleocapsid gene, respectively recovered ∼75, ∼71, and ∼7% target RSV mRNA after a 1 min of incubation time in a surrogate patient sample spiked with the target. RSV-specific beads required much longer incubation times to recover amounts of the target comparable to the other beads (∼77% at 180 min). As expected, silica-coated beads extracted total RNA, oligo (dT) beads selectively extracted total mRNA, and RSV-specific beads selectively extracted RSV N gene mRNA. The choice of bead functionality is generally dependent on the target detection strategy. The silica-coated beads are most suitable for applications that require nucleic acids other than mRNA, especially with detection strategies that are tolerant of a high concentration of nontarget background nucleic acids, such as RT-PCR. On the other hand, oligo (dT) beads are best-suited for mRNA targets, as they bind biomarkers rapidly, have relatively high recovery, and enable detection strategies to be performed directly on the bead surface. Sequence-specific beads may be best for applications that are not tolerant of a high concentration of nontarget nucleic acids that require short RNA sequences without poly(A) tails, such as microRNAs, or that perform RNA detection directly on the bead surface.

  17. 3T MRI and 128-slice dual-source CT cisternography images of the cranial nerves a brief pictorial review for clinicians.

    PubMed

    Roldan-Valadez, Ernesto; Martinez-Anda, Jaime J; Corona-Cedillo, Roberto

    2014-01-01

    There is a broad community of health sciences professionals interested in the anatomy of the cranial nerves (CNs): specialists in neurology, neurosurgery, radiology, otolaryngology, ophthalmology, maxillofacial surgery, radiation oncology, and emergency medicine, as well as other related fields. Advances in neuroimaging using high-resolution images from computed tomography (CT) and magnetic resonance (MR) have made highly-detailed visualization of brain structures possible, allowing normal findings to be routinely assessed and nervous system pathology to be detected. In this article we present an integrated perspective of the normal anatomy of the CNs established by radiologists and neurosurgeons in order to provide a practical imaging review, which combines 128-slice dual-source multiplanar images from CT cisternography and 3T MR curved reconstructed images. The information about the CNs includes their origin, course (with emphasis on the cisternal segments and location of the orifices at the skull base transmitting them), function, and a brief listing of the most common pathologies affecting them. The scope of the article is clinical anatomy; readers will find specialized texts presenting detailed information about particular topics. Our aim in this article is to provide a helpful reference for understanding the complex anatomy of the cranial nerves.

  18. L-cysteine functionalized magnetic nanoparticles (LCMNP): a novel magnetically separable organocatalyst for one-pot synthesis of 2-amino-4H-chromene-3-carbonitriles in water.

    PubMed

    Khalafi-Nezhad, Ali; Nourisefat, Maryam; Panahi, Farhad

    2015-07-28

    In this study, L-cysteine was chemically grafted to magnetic nanoparticles in order to prepare a reusable magnetic material incorporating an amino acid moiety. For this purpose, silica-coated magnetic nanoparticles (Fe3O4@SiO2) were reacted with trimethoxy(vinyl)silane to produce vinyl-functionalized magnetic nanoparticles (VMNP). Reaction of a VMNP substrate with L-cysteine in the presence of azobisisobutyronitrile (AIBN) resulted in the production of L-cysteine-functionalized magnetic nanoparticles (LCMNP). The LCMNP material was characterized using different microscopy and spectroscopy techniques such as FT-IR, XRD, TEM, SEM, EDX, VSM, and elemental analysis. Also, LCMNP was analyzed by thermogravimetric analysis (TGA) in order to determine its thermal behavior. The applicability of the LCMNP material was evaluated in a three-component coupling reaction between a nucleophile, salicylaldehyde and malononitrile as the catalyst for one-pot synthesis of 2-amino-4H-chromene-3-carbonitrile derivatives. The catalyst system showed high catalytic activity in this process and target products were obtained in high isolated yields in water as a green solvent. The LCMNP catalyst was reusable in this reaction at least 7 times with no significant decrease in its catalytic activity.

  19. Magnetic Helicity Spectrum of Solar Wind Fluctuations as a Function of the Angle with Respect to the Local Mean Magnetic Field

    NASA Astrophysics Data System (ADS)

    Podesta, J. J.; Gary, S. P.

    2011-06-01

    Magnetic field data acquired by the Ulysses spacecraft in high-speed streams over the poles of the Sun are used to investigate the normalized magnetic helicity spectrum σ m as a function of the angle θ between the local mean magnetic field and the flow direction of the solar wind. This spectrum provides important information about the constituent modes at the transition to kinetic scales that occurs near the spectral break separating the inertial range from the dissipation range. The energetically dominant signal at scales near the thermal proton gyroradius k bottomρ i ~ 1 often covers a wide band of propagation angles centered about the perpendicular direction, θ ~= 90° ± 30°. This signal is consistent with a spectrum of obliquely propagating kinetic Alfvén waves with k bottom Gt k par in which there is more energy in waves propagating away from the Sun and along the direction of the local mean magnetic field than toward the Sun. Moreover, this signal is principally responsible for the reduced magnetic helicity spectrum measured using Fourier transform techniques. The observations also reveal a subdominant population of nearly parallel propagating electromagnetic waves near the proton inertial scale k par c/ωpi ~ 1 that often exhibit high magnetic helicity |σ m | ~= 1. These waves are believed to be caused by proton pressure anisotropy instabilities that regulate distribution functions in the collisionless solar wind. Because of the existence of a drift of alpha particles with respect to the protons, the proton temperature anisotropy instability that operates when T pbottom/T ppar > 1 preferentially generates outward propagating ion-cyclotron waves and the fire-hose instability that operates when T pbottom/T ppar < 1 preferentially generates inward propagating whistler waves. These kinetic processes provide a natural explanation for the magnetic field observations.

  20. MAGNETIC HELICITY SPECTRUM OF SOLAR WIND FLUCTUATIONS AS A FUNCTION OF THE ANGLE WITH RESPECT TO THE LOCAL MEAN MAGNETIC FIELD

    SciTech Connect

    Podesta, J. J.; Gary, S. P.

    2011-06-10

    Magnetic field data acquired by the Ulysses spacecraft in high-speed streams over the poles of the Sun are used to investigate the normalized magnetic helicity spectrum {sigma}{sub m} as a function of the angle {theta} between the local mean magnetic field and the flow direction of the solar wind. This spectrum provides important information about the constituent modes at the transition to kinetic scales that occurs near the spectral break separating the inertial range from the dissipation range. The energetically dominant signal at scales near the thermal proton gyroradius k{sub perpendicular{rho}i} {approx} 1 often covers a wide band of propagation angles centered about the perpendicular direction, {theta} {approx_equal} 90{sup 0} {+-} 30{sup 0}. This signal is consistent with a spectrum of obliquely propagating kinetic Alfven waves with k{sub perpendicular} >> k{sub ||} in which there is more energy in waves propagating away from the Sun and along the direction of the local mean magnetic field than toward the Sun. Moreover, this signal is principally responsible for the reduced magnetic helicity spectrum measured using Fourier transform techniques. The observations also reveal a subdominant population of nearly parallel propagating electromagnetic waves near the proton inertial scale k{sub ||} c/{omega}{sub pi} {approx} 1 that often exhibit high magnetic helicity |{sigma}{sub m}| {approx_equal} 1. These waves are believed to be caused by proton pressure anisotropy instabilities that regulate distribution functions in the collisionless solar wind. Because of the existence of a drift of alpha particles with respect to the protons, the proton temperature anisotropy instability that operates when T{sub pperpendicular}/T{sub p||} > 1 preferentially generates outward propagating ion-cyclotron waves and the fire-hose instability that operates when T{sub pperpendicular}/T{sub p||} < 1 preferentially generates inward propagating whistler waves. These kinetic processes

  1. Functional magnetic resonance imaging blood oxygenation level-dependent signal and magnetoencephalography evoked responses yield different neural functionality in reading.

    PubMed

    Vartiainen, Johanna; Liljeström, Mia; Koskinen, Miika; Renvall, Hanna; Salmelin, Riitta

    2011-01-19

    It is often implicitly assumed that the neural activation patterns revealed by hemodynamic methods, such as functional magnetic resonance imaging (fMRI), and electrophysiological methods, such as magnetoencephalography (MEG) and electroencephalography (EEG), are comparable. In early sensory processing that seems to be the case, but the assumption may not be correct in high-level cognitive tasks. For example, MEG and fMRI literature of single-word reading suggests differences in cortical activation, but direct comparisons are lacking. Here, while the same human participants performed the same reading task, analysis of MEG evoked responses and fMRI blood oxygenation level-dependent (BOLD) signals revealed marked functional and spatial differences in several cortical areas outside the visual cortex. Divergent patterns of activation were observed in the frontal and temporal cortex, in accordance with previous separate MEG and fMRI studies of reading. Furthermore, opposite stimulus effects in the MEG and fMRI measures were detected in the left occipitotemporal cortex: MEG evoked responses were stronger to letter than symbol strings, whereas the fMRI BOLD signal was stronger to symbol than letter strings. The EEG recorded simultaneously during MEG and fMRI did not indicate neurophysiological differences that could explain the observed functional discrepancies between the MEG and fMRI results. Acknowledgment of the complementary nature of hemodynamic and electrophysiological measures, as reported here in a cognitive task using evoked response analysis in MEG and BOLD signal analysis in fMRI, represents an essential step toward an informed use of multimodal imaging that reaches beyond mere combination of location and timing of neural activation.

  2. Magnetic capture from blood rescues molecular motor function in diagnostic nanodevices

    PubMed Central

    2013-01-01

    Background Introduction of effective point-of-care devices for use in medical diagnostics is part of strategies to combat accelerating health-care costs. Molecular motor driven nanodevices have unique potentials in this regard due to unprecedented level of miniaturization and independence of external pumps. However motor function has been found to be inhibited by body fluids. Results We report here that a unique procedure, combining separation steps that rely on antibody-antigen interactions, magnetic forces applied to magnetic nanoparticles (MPs) and the specificity of the actomyosin bond, can circumvent the deleterious effects of body fluids (e.g. blood serum). The procedure encompasses the following steps: (i) capture of analyte molecules from serum by MP-antibody conjugates, (ii) pelleting of MP-antibody-analyte complexes, using a magnetic field, followed by exchange of serum for optimized biological buffer, (iii) mixing of MP-antibody-analyte complexes with actin filaments conjugated with same polyclonal antibodies as the magnetic nanoparticles. This causes complex formation: MP-antibody-analyte-antibody-actin, and magnetic separation is used to enrich the complexes. Finally (iv) the complexes are introduced into a nanodevice for specific binding via actin filaments to surface adsorbed molecular motors (heavy meromyosin). The number of actin filaments bound to the motors in the latter step was significantly increased above the control value if protein analyte (50–60 nM) was present in serum (in step i) suggesting appreciable formation and enrichment of the MP-antibody-analyte-antibody-actin complexes. Furthermore, addition of ATP demonstrated maintained heavy meromyosin driven propulsion of actin filaments showing that the serum induced inhibition was alleviated. Detailed analysis of the procedure i-iv, using fluorescence microscopy and spectroscopy identified main targets for future optimization. Conclusion The results demonstrate a promising approach for

  3. A resting state functional magnetic resonance imaging study of concussion in collegiate athletes.

    PubMed

    Czerniak, Suzanne M; Sikoglu, Elif M; Liso Navarro, Ana A; McCafferty, Joseph; Eisenstock, Jordan; Stevenson, J Herbert; King, Jean A; Moore, Constance M

    2015-06-01

    Sports-related concussions are currently diagnosed through multi-domain assessment by a medical professional and may utilize neurocognitive testing as an aid. However, these tests have only been able to detect differences in the days to week post-concussion. Here, we investigate a measure of brain function, namely resting state functional connectivity, which may detect residual brain differences in the weeks to months after concussion. Twenty-one student athletes (9 concussed within 6 months of enrollment; 12 non-concussed; between ages 18 and 22 years) were recruited for this study. All participants completed the Wisconsin Card Sorting Task and the Color-Word Interference Test. Neuroimaging data, specifically resting state functional Magnetic Resonance Imaging data, were acquired to examine resting state functional connectivity. Two sample t-tests were used to compare the neurocognitive scores and resting state functional connectivity patterns among concussed and non-concussed participants. Correlations between neurocognitive scores and resting state functional connectivity measures were also determined across all subjects. There were no significant differences in neurocognitive performance between concussed and non-concussed groups. Concussed subjects had significantly increased connections between areas of the brain that underlie executive function. Across all subjects, better neurocognitive performance corresponded to stronger brain connectivity. Even at rest, brains of concussed athletes may have to 'work harder' than their healthy peers to achieve similar neurocognitive results. Resting state brain connectivity may be able to detect prolonged brain differences in concussed athletes in a more quantitative manner than neurocognitive test scores.

  4. A Resting State Functional Magnetic Resonance Imaging Study of Concussion in Collegiate Athletes

    PubMed Central

    Czerniak, Suzanne M; Sikoglu, Elif M; Navarro, Ana A Liso; McCafferty, Joseph; Eisenstock, Jordan; Stevenson, J Herbert; King, Jean A; Moore, Constance M

    2015-01-01

    Sports-related concussions are currently diagnosed through multi-domain assessment by a medical professional and may utilize neurocognitive testing as an aide. However, these tests have only been able to detect differences in the days to week post-concussion. Here, we investigate a measure of brain function, namely resting state functional connectivity, which may detect residual brain differences in the weeks to months after concussion. Twenty-one student athletes (9 concussed within 6 months of enrollment; 12 non-concussed; between ages 18 to 22 years) were recruited for this study. All participants completed the Wisconsin Card Sort Task and the Color-Word Interference Test. Neuroimaging data, specifically resting state functional Magnetic Resonance Imaging data, were acquired to examine resting state functional connectivity. Two sample t-tests were used to compare the neurocognitive scores and resting state functional connectivity patterns among concussed and non-concussed participants. Correlations between neurocognitive scores and resting state functional connectivity measures were also determined across all subjects. There were no significant differences in neurocognitive performance between concussed and non-concussed groups. Concussed subjects had significantly increased connections between areas of the brain that underlie executive function. Across all subjects, better neurocognitive performance corresponded to stronger brain connectivity. Even at rest, brains of concussed athletes may have to ‘work harder’ than their healthy peers to achieve similar neurocognitive results. Resting state brain connectivity may be able to detect prolonged brain differences in concussed athletes in a more quantitative manner than neurocognitive test scores. PMID:25112544

  5. Magnetism, structures and stabilities of cluster assembled TM@Si nanotubes (TM = Cr, Mn and Fe): a density functional study.

    PubMed

    Dhaka, Kapil; Bandyopadhyay, Debashis

    2016-08-01

    The present study reports transition metal (TM = Cr, Mn and Fe) doped silicon nanotubes with tunable band structures and magnetic properties by careful selection of cluster assemblies as building blocks using the first-principles density functional theory. We found that the transition metal doping and in addition, the hydrogen termination process can stabilize the pure silicon nanoclusters or cluster assemblies and then it could be extended as magnetic nanotubes with finite magnetic moments. Study of the band structures and density of states (DOS) of different empty and TM doped nanotubes (Type 1 to Type 4) show that these nanotubes are useful as metals, semiconductors, semi-metals and half-metals. These designer magnetic materials could be useful in spintronics and magnetic devices of nanoscale order. PMID:27430742

  6. Magnetism, structures and stabilities of cluster assembled TM@Si nanotubes (TM = Cr, Mn and Fe): a density functional study.

    PubMed

    Dhaka, Kapil; Bandyopadhyay, Debashis

    2016-08-01

    The present study reports transition metal (TM = Cr, Mn and Fe) doped silicon nanotubes with tunable band structures and magnetic properties by careful selection of cluster assemblies as building blocks using the first-principles density functional theory. We found that the transition metal doping and in addition, the hydrogen termination process can stabilize the pure silicon nanoclusters or cluster assemblies and then it could be extended as magnetic nanotubes with finite magnetic moments. Study of the band structures and density of states (DOS) of different empty and TM doped nanotubes (Type 1 to Type 4) show that these nanotubes are useful as metals, semiconductors, semi-metals and half-metals. These designer magnetic materials could be useful in spintronics and magnetic devices of nanoscale order.

  7. Vacancy-induced magnetism in BaTiO3(001) thin films based on density functional theory.

    PubMed

    Cao, Dan; Cai, Meng-Qiu; Hu, Wang-Yu; Yu, Ping; Huang, Hai-Tao

    2011-03-14

    The origin of magnetism induced by vacancies on BaTiO(3)(001) surfaces is investigated systematically by first-principles calculations within density-functional theory. The calculated results show that O vacancy is responsible for the magnetism of the BaO-terminated surface and the magnetism of the TiO(2)-terminated surface is induced by Ti vacancy. For the BaO-terminated surface, the magnetism mainly arises from the unpaired electrons that are localized in the O vacancy basin. In contrast, for the TiO(2)-terminated surface, the magnetism mainly originates from the partially occupied O-2p states of the first nearest neighbor O atoms surrounding the Ti vacancy. These results suggest the possibility of implementing magneto-electric coupling in conventional ferroelectric materials.

  8. Evolution of an electron energy distribution function in a weak dc magnetic field in solenoidal inductive plasma

    SciTech Connect

    Lee, Min-Hyong; Choi, Seong Wook

    2008-12-01

    We investigated the evolution of the electron energy distribution function (EEDF) in a solenoidal inductively coupled plasma surrounded by an axial dc magnetic field. The increase in the dc magnetic field caused the EEDF to evolve from a bi-Maxwellian to a Maxwellian distribution. At the discharge center, the number of low energy electrons was significantly reduced while the high energy electron population showed little change when a weak dc magnetic field was present. However, at the discharge radial boundary, the high energy electron population decreased significantly with the magnetic field while the change in low energy population was not prominent compared to the discharge boundary. These changes in EEDFs at the boundary and center of the discharge are due to the radial confinement and the restriction of radial transport of electrons by dc magnetic field.

  9. Parceling of mesial frontal motor areas during ideation and movement using functional magnetic resonance imaging at 1.5 tesla.

    PubMed

    Tyszka, J M; Grafton, S T; Chew, W; Woods, R P; Colletti, P M

    1994-06-01

    Finger movement-related responses were identified in three discrete sites of mesial frontal cortex in 7 normal subjects using high resolution functional magnetic resonance imaging. During imagination of the same movements there was a differential response with rostral areas more active than caudal areas. Humans have multiple motor areas in mesial frontal cortex that subserve different functions in motor planning and execution.

  10. Affinity capture using peptide-functionalized magnetic nanoparticles to target Staphylococcus aureus

    NASA Astrophysics Data System (ADS)

    Kuo, Fang-Yin; Lin, Wei-Lien; Chen, Yu-Chie

    2016-04-01

    Staphylococcus aureus, a commonly found pathogen, can cause food poisoning and infections. Thus, it is necessary to develop analytical methods for the rapid screening of S. aureus in suspicious samples. Magnetic nanoparticles (MNPs) are widely used as affinity probes to selectively enrich target species from complex samples because of their high specific surface area and magnetic properties. The MNP surface should be functionalized to have the capability to target specific species. We herein propose a straightforward method to functionalize aluminum oxide-coated iron oxide (Fe3O4@Al2O3) MNPs with the peptide HHHHHHDEEGLFVD (D). The peptide D was comprised of three domains: polyhistidine (H6) used as the linker, DEE added as the spacer, and GLFVD used for targeting S. aureus. D was immobilized on the surface of Fe3O4@Al2O3 MNPs through H6-Al chelation. Our results showed that the D-functionalized Fe3O4@Al2O3 MNPs (D-Fe3O4 MNPs) possess the capability to target S. aureus. The selective trapping experiments were conducted under microwave-heating for only 60 s, and sufficient bacterial cells were trapped by the MNPs to be identified by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). We demonstrated that the D-Fe3O4@Al2O3 MNPs combined with MALDI-MS can be used to rapidly characterize trace amounts of S. aureus in complex juice and egg samples.Staphylococcus aureus, a commonly found pathogen, can cause food poisoning and infections. Thus, it is necessary to develop analytical methods for the rapid screening of S. aureus in suspicious samples. Magnetic nanoparticles (MNPs) are widely used as affinity probes to selectively enrich target species from complex samples because of their high specific surface area and magnetic properties. The MNP surface should be functionalized to have the capability to target specific species. We herein propose a straightforward method to functionalize aluminum oxide-coated iron oxide (Fe3O4@Al2O3) MNPs with the

  11. Neuropeptide Y potentiates beta-adrenergic stimulation of lipolysis in 3T3-L1 adipocytes.

    PubMed

    Li, Raymond; Guan, Haiyan; Yang, Kaiping

    2012-10-10

    Recently, we have shown that neuropeptide Y (NPY) is produced and upregulated in visceral adipose tissue of an early-life programmed rat model of central obesity. Moreover, we have demonstrated that NPY promotes proliferation of adipocyte precursor cells and contributes to the pathogenesis of obesity. However, the role of NPY in regulating adipocyte metabolism is poorly understood. The present study was designed to examine the effects of NPY on adipocyte metabolic function using 3T3-L1 adipocytes as an in vitro cell model system. We found that although it did not affect basal lipolysis, NPY potentiated isoproterenol (a β-adrenergic receptor agonist) stimulated lipolysis. Furthermore, this potentiation occurred upstream of adenylyl cyclase, since NPY did not enhance forskolin (an activator of adenylyl cyclase) stimulated lipolysis. In addition, NPY also augmented isoproterenol-stimulated phosphorylation of hormone sensitive lipase. In contrast, NPY did not alter the expression of several key lipolytic and lipogenic enzymes/proteins. Taken together, our results revealed a novel cross talk between the NPY and β-adrenergic signaling pathways in regulating lipolysis. Thus, the present findings add a new dimension to the dynamic role NPY plays in regulating energy balance.

  12. Flow cytometric analysis of intracellular pH in 3T3 cells.

    PubMed

    Gillies, R J; Cook, J; Fox, M H; Giuliano, K A

    1987-07-01

    Techniques to determine intracellular pH generally report the average pH of population and do not indicate whether or not there is significant variance among cells within the population. Population variance is important to ascribe pH changes on a per cell basis. The magnitude of the pH change in individual cells is important to ascribe physiological function to changes in pH. To determine the variability of cell responses, we have used dual wavelength fluorescence emission spectroscopy of intracellular dicyanohydroquinone monitored with flow cytometry to determine the pH of normal and transformed 3T3 cells in response to serum or serum components. All cells were mechanically harvested from subconfluent cultures. Large differences in pH were observed between serum-deprived and serum-conditioned normal, but not transformed, cells. Addition of serum caused cytosolic alkalinization, with the serum-deprived cells responding more slowly. Titration of cells with submaximal doses of serum indicate that the response of pH is graded, that all cells respond in similar manner, and that the relative affinity of transformed cells for the serum components causing the pH effect is about twice that of normal cells.

  13. Visualizing Functional Pathways in the Human Brain Using Correlation Tensors and Magnetic Resonance Imaging

    PubMed Central

    Ding, Zhaohua; Xu, Ran; Bailey, Stephen K.; Wu, Tung-Lin; Morgan, Victoria L.; Cutting, Laurie E.; Anderson, Adam W.; Gore, John C.

    2016-01-01

    Functional magnetic resonance imaging usually detects changes in blood oxygenation level dependent (BOLD) signals from T2*-sensitive acquisitions, and is most effective in detecting activity in brain cortex which is irrigated by rich vasculature to meet high metabolic demands. We recently demonstrated that MRI signals from T2*-sensitive acquisitions in a resting state exhibit structure-specific temporal correlations along white matter tracts. In this report we validate our preliminary findings and introduce spatio-temporal functional correlation tensors to characterize the directional preferences of temporal correlations in MRI signals acquired at rest. The results bear a remarkable similarity to data obtained by diffusion tensor imaging but without any diffusion-encoding gradients. Just as in gray matter, temporal correlations in resting state signals may reflect intrinsic synchronizations of neural activity in white matter. Here we demonstrate that functional correlation tensors are able to visualize long range white matter tracts as well as short range sub-cortical fibers imaged at rest, and that evoked functional activities alter these structures and enhance the visualization of relevant neural circuitry. Furthermore, we explore the biophysical mechanisms underlying these phenomena by comparing pulse sequences, which suggest that white matter signal variations are consistent with hemodynamic (BOLD) changes associated with neural activity. These results suggest new ways to evaluate MRI signal changes within white matter. PMID:26477562

  14. Functional magnetic resonance imaging exploration of combined hand and speech movements in Parkinson's disease.

    PubMed

    Pinto, Serge; Mancini, Laura; Jahanshahi, Marjan; Thornton, John S; Tripoliti, Elina; Yousry, Tarek A; Limousin, Patricia

    2011-10-01

    Among the repertoire of motor functions, although hand movement and speech production tasks have been investigated widely by functional neuroimaging, paradigms combining both movements have been studied less so. Such paradigms are of particular interest in Parkinson's disease, in which patients have specific difficulties performing two movements simultaneously. In 9 unmedicated patients with Parkinson's disease and 15 healthy control subjects, externally cued tasks (i.e., hand movement, speech production, and combined hand movement and speech production) were performed twice in a random order and functional magnetic resonance imaging detected cerebral activations, compared to the rest. F-statistics tested within-group (significant activations at P values < 0.05, familywise error corrected), between-group, and between-task comparisons (regional activations significant at P values < 0.001, uncorrected, with cluster size > 10 voxels). For control subjects, the combined task activations comprised the sum of those obtained during hand movement and speech production performed separately, reflecting the neural correlates of performing movements sharing similar programming modalities. In patients with Parkinson's disease, only activations underlying hand movement were observed during the combined task. We interpreted this phenomenon as patients' potential inability to recruit facilitatory activations while performing two movements simultaneously. This lost capacity could be related to a functional prioritization of one movement (i.e., hand movement), in comparison with the other (i.e., speech production). Our observation could also reflect the inability of patients with Parkinson's disease to intrinsically engage the motor coordination necessary to perform a combined task.

  15. ATF3 inhibits adipocyte differentiation of 3T3-L1 cells

    SciTech Connect

    Jang, Min Kyung; Kim, Cho Hee; Seong, Je Kyung; Jung, Myeong Ho

    2012-04-27

    Highlights: Black-Right-Pointing-Pointer Overexpression of ATF3 inhibits adipocyte differentiation in 3T3-L1 cells. Black-Right-Pointing-Pointer Overexpression of ATF3 represses C/EBP{alpha} expression. Black-Right-Pointing-Pointer ATF3 directly binds to mouse C/EBP{alpha} promoter spanning from -1928 to -1907. Black-Right-Pointing-Pointer ATF3 may play a role in hypoxia-mediated inhibition of adipocyte differentiation. -- Abstract: ATF3 is a stress-adaptive gene that regulates proliferation or apoptosis under stress conditions. However, the role of ATF3 is unknown in adipocyte cells. Therefore, in this study, we investigated the functional role of ATF3 in adipocytes. Both lentivirus-mediated overexpression of ATF3 and stably-overexpressed ATF3 inhibited adipocyte differentiation in 3T3-L1 cells, as revealed by decreased lipid staining with oil red staining and reduction in adipogenic genes. Thapsigargin treatment and overexpression of ATF3 decreased C/EBP{alpha} transcript and repressed the activity of the 3.6-kb mouse C/EBP{alpha} promoter, demonstrating that ATF3 downregulates C/EBP{alpha} expression. Transfection studies using mutant constructs containing 5 Prime -deletions in the C/EBP{alpha} promoter revealed that a putative ATF/CRE element, GGATGTCA, is located between -1921 and -1914. Electrophoretic mobility shift assay and chromatin immunoprecipitation assay demonstrated that ATF3 directly binds to mouse C/EBP{alpha} promoter spanning from -1928 to -1907. Both chemical hypoxia-mimetics or physical hypoxia led to reduce the C/EBP{alpha} mRNA and repress the promoter activity of the C/EBP{alpha} gene, whereas increase ATF3 mRNA, suggesting that ATF3 may contribute to the inhibition of adipocyte differentiation in hypoxia through downregulation of C/EBP{alpha} expression. Collectively, these results demonstrate that ATF3 represses the C/EBP{alpha} gene, resulting in inhibition of adipocyte differentiation, and thus plays a role in hypoxia-mediated inhibition

  16. Influence of intermittency on the anisotropy of magnetic structure functions of solar wind turbulence

    NASA Astrophysics Data System (ADS)

    Pei, Zhongtian; He, Jiansen; Wang, Xin; Tu, Chuanyi; Marsch, Eckart; Wang, Linghua; Yan, Limei

    2016-02-01

    Intermittency appears to be connected with the spectral anisotropy of solar wind turbulence. We use the Local Intermittency Measure to identify and remove intermittency from the magnetic field data measured by the Ulysses spacecraft in fast solar wind. Structure functions are calculated based on the time sequences as obtained before and after removing intermittency and arranged by time scale (τ) and ΘRB (the angle between local mean magnetic field B0 and radial direction R). Thus, the scaling exponent (ξ(p, ΘRB)) of every structure function of order (p) is obtained for different angles. Before removing intermittency, ξ(p, ΘRB) shows a distinctive dependence on ΘRB: from monofractal scaling law at ΘRB ~0° to multifractal scaling law at ΘRB ~90°. In contrast after eliminating the intermittency, ξ(p, ΘRB) is found to be more monofractal for all ΘRB. The extended structure-function model is applied to ξ(p, ΘRB), revealing differences of its fitting parameters α (a proxy of the power spectral index) and P1 (fragmentation fraction) for the cases with and without intermittency. Parameter α shows an evident angular trend falling from 1.9 to 1.6 for the case with intermittency but has a relatively flat profile around 1.8 for the case without intermittency. Parameter P1 rises from around 0.5 to above 0.8 with increasing ΘRB for the intermittency case and is located between 0.5 and 0.8 for the case lacking intermittency. Therefore, we may infer that it is the anisotropy of intermittency that causes the scaling anisotropy of energy spectra and the unequal fragmentation of energy cascading.

  17. Regulatory T Cells in Melanoma Revisited by a Computational Clustering of FOXP3+ T Cell Subpopulations

    PubMed Central

    Fujii, Hiroko; Josse, Julie; Tanioka, Miki; Miyachi, Yoshiki; Husson, François

    2016-01-01

    CD4+ T cells that express the transcription factor FOXP3 (FOXP3+ T cells) are commonly regarded as immunosuppressive regulatory T cells (Tregs). FOXP3+ T cells are reported to be increased in tumor-bearing patients or animals and are considered to suppress antitumor immunity, but the evidence is often contradictory. In addition, accumulating evidence indicates that FOXP3 is induced by antigenic stimulation and that some non-Treg FOXP3+ T cells, especially memory-phenotype FOXP3low cells, produce proinflammatory cytokines. Accordingly, the subclassification of FOXP3+ T cells is fundamental for revealing the significance of FOXP3+ T cells in tumor immunity, but the arbitrariness and complexity of manual gating have complicated the issue. In this article, we report a computational method to automatically identify and classify FOXP3+ T cells into subsets using clustering algorithms. By analyzing flow cytometric data of melanoma patients, the proposed method showed that the FOXP3+ subpopulation that had relatively high FOXP3, CD45RO, and CD25 expressions was increased in melanoma patients, whereas manual gating did not produce significant results on the FOXP3+ subpopulations. Interestingly, the computationally identified FOXP3+ subpopulation included not only classical FOXP3high Tregs, but also memory-phenotype FOXP3low cells by manual gating. Furthermore, the proposed method successfully analyzed an independent data set, showing that the same FOXP3+ subpopulation was increased in melanoma patients, validating the method. Collectively, the proposed method successfully captured an important feature of melanoma without relying on the existing criteria of FOXP3+ T cells, revealing a hidden association between the T cell profile and melanoma, and providing new insights into FOXP3+ T cells and Tregs. PMID:26864030

  18. Magnetic properties and paleointensities as function of depth in a Hawai'ian lava flow

    NASA Astrophysics Data System (ADS)

    Dekkers, M. J.; de Groot, L. V.; ter Maat, G. W.

    2013-12-01

    The outcome of paleointensity experiments largely depends on the rock-magnetic properties of the samples. To assess the relation between volcanic emplacement processes and rock-magnetic properties we sampled a vertical transect in a ~6 m thick inflated lava flow at Hawai'i, with an age of 588 (558 - 640) AD (Rubin et al., 1987, recalibrated with INTCAL.09). This profile was sampled at sixteen levels in the flow; at six of these levels up to twelve samples were taken horizontally to have sufficient sample material for paleointensity experiments. Samples from all levels were rock magnetically characterized by determining hysteresis loops and FORC (first-order-reversal-curve) diagrams, and the low-field susceptibility, all at room temperature. To test for thermochemical alteration the temperature dependence of the low-field susceptibility and magnetization was determined. Overall, rock magnetic properties appear to vary as function of distance from the top; the observations can be correlated to the typical cooling rate profile for such a flow. The solidified crust under which the flow continued to flow during emplacement is ~1.8 m thick. Its rock-magnetic properties - notably the low-field susceptibility and the coercivity ratio - are more variable than those of the inflated part underneath. FORC diagrams indicate a fair portion of very small superparamagnetic particles in the top and to a lesser extent the bottom parts of the flow. In line with their faster cooling the dominant titanomagnetite composition is ~TM60 with associated low Curie and unblocking temperatures. The titanomagnetite in the slower cooled central part of the flow is unmixed into the magnetite (~TM0) and ülvospinel end-members; the remanence has therefore high Curie and unblocking temperatures. FORC diagrams and hysteresis parameters indicate larger pseudo-single-domain particles. We performed both IZZI-Thellier and calibrated pseudo-Thellier (AGU Fall 2012 contribution GP43A-1122, submitted

  19. Surface Functionalization of Magnetic Iron Oxide Nanoparticles for MRI Applications – Effect of Anchoring Group and Ligand Exchange Protocol

    PubMed Central

    Smolensky, Eric D.; Park, Hee-Yun E.; Berquó, Thelma S.; Pierre, Valérie C.

    2011-01-01

    Hydrophobic magnetite nanoparticles synthesized from thermal decomposition of iron salts must be rendered hydrophilic for their application as MRI contrast agents. This process requires refunctionalizing the surface of the nanoparticles with a hydrophilic organic coating such as polyethylene glycol. Two parameters were found to influence the magnetic behavior and relaxivity of the resulting hydrophilic iron oxide nanoparticles: the functionality of the anchoring group and the protocol followed for the functionalization. Nanoparticles coated with PEGs via a catecholate-type anchoring moiety maintain the saturation magnetization and relaxivity of the hydrophobic magnetite precursor. Other anchoring functionalities, such as phosphonate, carboxylate, and dopamine decrease the magnetization and relaxivity of the contrast agent. The protocol for functionalizing the nanoparticles also influences the magnetic behavior of the material. Nanoparticles refunctionalized according to a direct biphasic protocol exhibit higher relaxivity than those refunctionalized according to a two-step procedure which first involves stripping the nanoparticles. This research presents the first systematic study of both the binding moiety and the functionalization protocol on the relaxivity and magnetization of water-soluble coated iron oxide nanoparticles used as MRI contrast agents. PMID:21861279

  20. Fucoxanthin and its metabolite, fucoxanthinol, suppress adipocyte differentiation in 3T3-L1 cells.

    PubMed

    Maeda, Hayato; Hosokawa, Masashi; Sashima, Tokutake; Takahashi, Nobuyuki; Kawada, Teruo; Miyashita, Kazuo

    2006-07-01

    Fucoxanthin is a major carotenoid found in edible seaweed such as Undaria pinnatifida and Hijikia fusiformis. We investigated the suppressive effects of fucoxanthin and its metabolite, fucoxanthinol, on the differentiation of 3T3-L1 preadipocytes to adipocytes. Fucoxanthin inhibited intercellular lipid accumulation during adipocyte differentiation of 3T3-L1 cells. Furthermore, fucoxanthin was converted to fucoxanthinol in 3T3-L1 cells. Fucoxanthinol also exhibited suppressive effects on lipid accumulation and decreased glycerol-3-phosphate dehydrogenase activity, an indicator of adipocyte differentiation. The suppressive effect of fucoxanthinol was stronger than that of fucoxanthin. In addition, in 3T3-L1 cells treated with fucoxanthin and fucoxanthinol, peroxisome proliferator-activated receptor gamma (PPARgamma), which regulates adipogenic gene expression, was down-regulated in a dose-dependent manner. These results suggest that fucoxanthin and fucoxanthinol inhibit the adipocyte differentiation of 3T3-L1 cells through down-regulation of PPARgamma. Fucoxanthinol had stronger suppressive effects than fucoxanthin on adipocyte differentiation in 3T3-L1 cells. PMID:16786166

  1. Transformation and apoptosis of NIH/3T3 cells treated with nickel-smelting fumes.

    PubMed

    Jin, Yan-Tao; Wu, Yong-Hui; Hu, Fu-Lan; Hu, Xue-Ying

    2009-01-01

    The purpose of this study was to investigate the transformation and apoptosis of NIH/3T3 cells treated with nickel (Ni) smelting fumes. Cytotoxicity of NIH/3T3 cells was detected with a methyl thiazolyl tetrazolium (MTT) colorimetric assay. The cell translation model was established by cell focus translation using two types of Ni-smelting fumes from a Ni smelting plant in China. The transformed focus was determined by soft agar culture assay. The apoptotic characteristics of NIH/3T3 cells treated with Ni-smelting fumes were detected by flow cytometry using Annexin V-FITC and PI as markers. The DNA fragment of apoptosis in NIH/3T3 cells treated with nickel smelting fumes was detected by observing agarose electrophoresis and morphological characteristics of cells under electron microscopy. With increase in exposure time, growth of NIH/3T3 cells was inhibited. The NIH/3T3 cell transformation model was established successfully using two Ni-smelting fumes, and the transformed cells grow in soft agar. No apoptosis peak was detected by flow cytometry. Apoptotic cells characterized by necrosis were observed using electron microscopy. There was no apparent "ladder" observed by DNA fragment analysis. Data indicated that Ni-smelting fumes produced cytotoxicity by mechanisms associated with necrosis but not apoptosis. PMID:19492236

  2. Mitigative Effect of Erythromycin on PMMA Challenged Preosteoblastic MC3T3-E1 Cells

    PubMed Central

    Shen, Yi; Wang, Weili; Li, Xiaomiao; Markel, David C.; Ren, Weiping

    2014-01-01

    Background. Aseptic loosening (AL) is a major complication of total joint replacement. Recent approaches to limiting AL have focused on inhibiting periprosthetic inflammation and osteoclastogenesis. Questions/Purposes. The purpose of this study was to determine the effects of erythromycin (EM) on polymethylmethacrylate (PMMA) particle-challenged MC3T3 osteoblast precursor cells. Methods. MC3T3 cells were pretreated with EM (0–10 μg/mL) and then stimulated with PMMA (1 mg/mL). Cell viability was evaluated by both a lactate dehydrogenase (LDH) release assay and cell counts. Cell differentiation was determined by activity of alkaline phosphatase (ALP). Gene expression was measured via real-time quantitative RT-PCR. Results. We found that exposure to PMMA particles reduced cellular viability and osteogenetic potential in MC3T3 cell line. EM treatment mitigated the effects of PMMA particles on the proliferation, viability and differentiation of MC3T3 cells. PMMA decreased the gene expression of Runx2, osterix and osteocalcin, which can be partially restored by EM treatment. Furthermore, EM suppressed PMMA- induced increase of NF-κB gene expression. Conclusions. These data demonstrate that EM mitigates the effects of PMMA on MC3T3 cell viability and differentiation, in part through downregulation of NF-κB pathway. EM appeared to represent an anabolic agent on MC3T3 cells challenged with PMMA particles. PMID:25110723

  3. Transformation and apoptosis of NIH/3T3 cells treated with nickel-smelting fumes.

    PubMed

    Jin, Yan-Tao; Wu, Yong-Hui; Hu, Fu-Lan; Hu, Xue-Ying

    2009-01-01

    The purpose of this study was to investigate the transformation and apoptosis of NIH/3T3 cells treated with nickel (Ni) smelting fumes. Cytotoxicity of NIH/3T3 cells was detected with a methyl thiazolyl tetrazolium (MTT) colorimetric assay. The cell translation model was established by cell focus translation using two types of Ni-smelting fumes from a Ni smelting plant in China. The transformed focus was determined by soft agar culture assay. The apoptotic characteristics of NIH/3T3 cells treated with Ni-smelting fumes were detected by flow cytometry using Annexin V-FITC and PI as markers. The DNA fragment of apoptosis in NIH/3T3 cells treated with nickel smelting fumes was detected by observing agarose electrophoresis and morphological characteristics of cells under electron microscopy. With increase in exposure time, growth of NIH/3T3 cells was inhibited. The NIH/3T3 cell transformation model was established successfully using two Ni-smelting fumes, and the transformed cells grow in soft agar. No apoptosis peak was detected by flow cytometry. Apoptotic cells characterized by necrosis were observed using electron microscopy. There was no apparent "ladder" observed by DNA fragment analysis. Data indicated that Ni-smelting fumes produced cytotoxicity by mechanisms associated with necrosis but not apoptosis.

  4. [Envelope protein of Jaagsiekte sheep retrovious expressed in NIH3T3 cells promotes cell proliferation].

    PubMed

    DU, Fangyuan; Chen, Dayong; Zhang, Yufei; Sun, Xiaolin; Guo, Wenqing; Liu, Shuying

    2016-09-01

    Objective To explore the influence of the exogenous Jaagsiekte sheep retrovious (exJSRV) envelope protein (Env) on NIH3T3 cell proliferation. Methods A recombinant plasmid pcDNA4/myc-His/exJSRV- env carrying exJSRV- env gene was constructed, and then the correctness of the recombinant plasmid was identified by PCR, restriction enzyme digestion and sequencing. The recombinant plasmid pcDNA4/myc-His/exJSRV- env was transiently transfected into NIH3T3 cells by Lipofectamine(TM) LTX. After the transfection of the recombinant plasmid, the