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Sample records for lymphotropic nanoparticle-enhanced magnetic

  1. Resonant Raman Scattering from Silicon Nanoparticles Enhanced by Magnetic Response

    CERN Document Server

    Dmitriev, Pavel A; Milichko, Valentin A; Makarov, Sergey V; Mukhin, Ivan S; Samusev, Anton K; Krasnok, Alexander E; Belov, Pavel A; Kivshar, Yuri S

    2016-01-01

    Enhancement of optical response with high-index dielectric nanoparticles is attributed to the excitation of their Mie-type magnetic and electric resonances. Here we study Raman scattering from crystalline silicon nanoparticles and reveal that magnetic dipole modes have much stronger effect on the scattering than electric modes of the same order. We demonstrate experimentally a 140-fold enhancement of Raman signal from individual silicon spherical nanoparticles at the magnetic dipole resonance. Our results confirm the importance of the optically-induced magnetic response of subwavelength dielectric nanoparticles for enhancing light-matter interactions.

  2. Cellular uptake of magnetite nanoparticles enhanced by NdFeB magnets in staggered arrangement

    Science.gov (United States)

    Lu, Yi-Ching; Chang, Fan-Yu; Tu, Shu-Ju; Chen, Jyh-Ping; Ma, Yunn-Hwa

    2017-04-01

    Magnetic force may greatly enhance uptake of magnetic nanoparticles (MNPs) by cultured cells; however, the effects of non-uniformity of magnetic field/ magnetic gradient on MNP internalization in culture has not been elucidated. Cellular uptake of polyacrylic acid coated-MNP by LN229 cells was measured with cylindrical NdFeB magnets arranged in a staggered pattern. The magnetic field generated by placing a magnet underneath (H-field) elicited a homogenous distribution of MNPs on the cells in culture; whereas the field without magnet underneath (L-field) resulted in MNP distribution along the edge of the wells. Cell-associated MNP (MNPcell) appeared to be magnetic field- and concentration-dependent. In H-field, MNPcell reached plateau within one hour of exposure to MNP with only one-min application of the magnetic force in the beginning of incubation; continuous presence of the magnet for 2 h did not further increase MNPcell, suggesting that magnetic force-induced uptake may be primarily contributed to enhanced MNP sedimentation. Although MNP distribution was much inhomogeneous in L-field, averaged MNPcell in the L-field may reach as high as 80% of that in H-field during 1-6 h incubation, suggesting high capacity of MNP internalization. In addition, no significant difference was observed in MNPcell analyzed by flow cytometry with the application of H-field of staggered plate vs. filled magnet plate. Therefore, biological variation may dominate MNP internalization even under relatively uniformed magnetic field; whereas non-uniformed magnetic field may serve as a model for tumor targeting with MNPs in vivo.

  3. RGDS-functionalized polyethylene glycol hydrogel-coated magnetic iron oxide nanoparticles enhance specific intracellular uptake by HeLa cells

    OpenAIRE

    Nazli C; Ergenc TI; Yar Y; Acar HY; Kizilel S

    2012-01-01

    © 2012 Nazli et al, publisher and licensee Dove Medical Press Ltd. This is an Open Access article which permits unrestricted noncommercial use, provided the original work is properly cited. International Journal of Nanomedicine 2012:7 1903–1920 International Journal of Nanomedicine RGDS-functionalized polyethylene glycol hydrogel-coated magnetic iron oxide nanoparticles enhance specific intracellular uptake by HeLa cells Caner Nazli1 Tugba Ipek Ergenc2 Yasemin Ya...

  4. Novel Gd nanoparticles enhance vascular contrast for high-resolution magnetic resonance imaging.

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    Tot Bui

    Full Text Available BACKGROUND: Gadolinium (Gd, with its 7 unpaired electrons in 4f orbitals that provide a very large magnetic moment, is proven to be among the best agents for contrast enhanced MRI. Unfortunately, the most potent MR contrast agent based on Gd requires relatively high doses of Gd. The Gd-chelated to diethylene-triamine-penta-acetic acid (DTPA, or other derivatives (at 0.1 mmole/kg recommended dose, distribute broadly into tissues and clear through the kidney. These contrast agents carry the risk of Nephrogenic Systemic Fibrosis (NSF, particularly in kidney impaired subjects. Thus, Gd contrast agents that produce higher resolution images using a much lower Gd dose could address both imaging sensitivity and Gd safety. METHODOLOGY/PRINCIPAL FINDINGS: To determine whether a biocompatible lipid nanoparticle with surface bound Gd can improve MRI contrast sensitivity, we constructed Gd-lipid nanoparticles (Gd-LNP containing lipid bound DTPA and Gd. The Gd-LNP were intravenously administered to rats and MR images collected. We found that Gd in Gd-LNP produced a greater than 33-fold higher longitudinal (T(1 relaxivity, r(1, constant than the current FDA approved Gd-chelated contrast agents. Intravenous administration of these Gd-LNP at only 3% of the recommended clinical Gd dose produced MRI signal-to-noise ratios of greater than 300 in all vasculatures. Unlike current Gd contrast agents, these Gd-LNP stably retained Gd in normal vasculature, and are eliminated predominately through the biliary, instead of the renal system. Gd-LNP did not appear to accumulate in the liver or kidney, and was eliminated completely within 24 hrs. CONCLUSIONS/SIGNIFICANCE: The novel Gd-nanoparticles provide high quality contrast enhanced vascular MRI at 97% reduced dose of Gd and do not rely on renal clearance. This new agent is likely to be suitable for patients exhibiting varying degrees of renal impairment. The simple and adaptive nanoparticle design could accommodate

  5. Nanoparticles enhance brain delivery of blood-brain barrier-impermeable probes for in vivo optical and magnetic resonance imaging.

    Science.gov (United States)

    Koffie, Robert M; Farrar, Christian T; Saidi, Laiq-Jan; William, Christopher M; Hyman, Bradley T; Spires-Jones, Tara L

    2011-11-15

    Several imaging modalities are suitable for in vivo molecular neuroimaging, but the blood-brain barrier (BBB) limits their utility by preventing brain delivery of most targeted molecular probes. We prepared biodegradable nanocarrier systems made up of poly(n-butyl cyanoacrylate) dextran polymers coated with polysorbate 80 (PBCA nanoparticles) to deliver BBB-impermeable molecular imaging probes into the brain for targeted molecular neuroimaging. We demonstrate that PBCA nanoparticles allow in vivo targeting of BBB-impermeable contrast agents and staining reagents for electron microscopy, optical imaging (multiphoton), and whole brain magnetic resonance imaging (MRI), facilitating molecular studies ranging from individual synapses to the entire brain. PBCA nanoparticles can deliver BBB-impermeable targeted fluorophores of a wide range of sizes: from 500-Da targeted polar molecules to 150,000-Da tagged immunoglobulins into the brain of living mice. The utility of this approach is demonstrated by (i) development of a "Nissl stain" contrast agent for cellular imaging, (ii) visualization of amyloid plaques in vivo in a mouse model of Alzheimer's disease using (traditionally) non-BBB-permeable reagents that detect plaques, and (iii) delivery of gadolinium-based contrast agents into the brain of mice for in vivo whole brain MRI. Four-dimensional real-time two-photon and MR imaging reveal that brain penetration of PBCA nanoparticles occurs rapidly with a time constant of ∼18 min. PBCA nanoparticles do not induce nonspecific BBB disruption, but collaborate with plasma apolipoprotein E to facilitate BBB crossing. Collectively, these findings highlight the potential of using biodegradable nanocarrier systems to deliver BBB-impermeable targeted molecular probes into the brain for diagnostic neuroimaging.

  6. Nanoparticles enhance brain delivery of blood–brain barrier-impermeable probes for in vivo optical and magnetic resonance imaging

    Science.gov (United States)

    Koffie, Robert M.; Farrar, Christian T.; Saidi, Laiq-Jan; William, Christopher M.; Hyman, Bradley T.; Spires-Jones, Tara L.

    2011-01-01

    Several imaging modalities are suitable for in vivo molecular neuroimaging, but the blood–brain barrier (BBB) limits their utility by preventing brain delivery of most targeted molecular probes. We prepared biodegradable nanocarrier systems made up of poly(n-butyl cyanoacrylate) dextran polymers coated with polysorbate 80 (PBCA nanoparticles) to deliver BBB-impermeable molecular imaging probes into the brain for targeted molecular neuroimaging. We demonstrate that PBCA nanoparticles allow in vivo targeting of BBB-impermeable contrast agents and staining reagents for electron microscopy, optical imaging (multiphoton), and whole brain magnetic resonance imaging (MRI), facilitating molecular studies ranging from individual synapses to the entire brain. PBCA nanoparticles can deliver BBB-impermeable targeted fluorophores of a wide range of sizes: from 500-Da targeted polar molecules to 150,000-Da tagged immunoglobulins into the brain of living mice. The utility of this approach is demonstrated by (i) development of a “Nissl stain” contrast agent for cellular imaging, (ii) visualization of amyloid plaques in vivo in a mouse model of Alzheimer's disease using (traditionally) non–BBB-permeable reagents that detect plaques, and (iii) delivery of gadolinium-based contrast agents into the brain of mice for in vivo whole brain MRI. Four-dimensional real-time two-photon and MR imaging reveal that brain penetration of PBCA nanoparticles occurs rapidly with a time constant of ∼18 min. PBCA nanoparticles do not induce nonspecific BBB disruption, but collaborate with plasma apolipoprotein E to facilitate BBB crossing. Collectively, these findings highlight the potential of using biodegradable nanocarrier systems to deliver BBB-impermeable targeted molecular probes into the brain for diagnostic neuroimaging. PMID:22065785

  7. Magnetic resonance imaging for Human T-cell lymphotropic virus type 1 (HTLV1- associated myelopathy/tropical spastic paraparesis patients: a systematic review

    Directory of Open Access Journals (Sweden)

    Fariba Zemorshidi

    2015-06-01

    Full Text Available Introduction: Human T-cell lymphotropic virus type 1 (HTLV-1 associated myelopathy/tropical spastic paraparesis is a chronic progressive neurologic disease which might be associated by brain and spinal cord atrophy and lesions. Here we systematically reviewed the brain and spinal cord abnormalities reported by using magnetic resonance imaging modality on HTLV-1 associated myelopathy/tropical spastic paraparesis patients. Methods: PubMed was searched for all the relevant articles which used magnetic resonance imaging for patients with human HTLV-1 associated myelopathy/tropical spastic paraparesis disease. Included criteria were all the cohort and case series on with at least 10 patients. We had no time limitation for searched articles, but only English language articles were included in our systematic review. Exclusion criteria were none-English articles, case reports, articles with less than 10 patients, spastic paraparesis patients with unknown etiology, and patients with HTLVII. Results: Total of 14 relevant articles were extracted after studying title, abstracts, and full text of the irrelevant articles. Only 2/14 articles, reported brain atrophy incidence. 5/14 articles studied the brain lesions prevalence. Spinal cord atrophy and lesions, each were studied in 6/14 articles.Discussion: According to the extracted data, brain atrophy does not seem to happen frequently in patients with HTLV-1 associated myelopathy/tropical spastic paraparesis. None-specific brain lesions identified in articles are indicative of low specificity of magnetic resonance imaging technique despite its high sensitivity. Conclusion: Prevalence of spinal cord lesions and atrophy in these patients might be due to the degenerative processes associated with aging phenomenon. Further larger studies in endemic areas can more accurately reveal the specificity of magnetic resonance imaging for these patients.

  8. A Thermofluid Analysis of the Magnetic Nanoparticles Enhanced Heating Effects in Tissues Embedded with Large Blood Vessel during Magnetic Fluid Hyperthermia

    Directory of Open Access Journals (Sweden)

    Koustov Adhikary

    2016-01-01

    Full Text Available The thermal effect developed due to the heating of magnetic nanoparticles (MNPs in presence of external magnetic field can be precisely controlled by the proper selection of magnetic absorption properties of the MNPs. The present paper deals with the numerical simulation of temperature field developed within or outside the tumor, in the presence of an external alternating magnetic field, using a thermofluidic model developed using ANSYS FLUENT®. A three-layer nonuniform tissue structure with one or two blood vessels surrounding the tumor is considered for the present simulation. The results obtained clearly suggest that the volumetric distribution pattern of MNPs within the tumor has a strong influence on the temperature field developed. The linear pattern of volumetric distribution has a strong effect over the two other types of distribution considered herein. Various other important factors like external magnetic field intensity, frequency, vascular congestion, types of MNP material, and so forth are considered to find the influence on the temperature within the tumor. Results show that proper selection of these parameters has a strong influence on the desired therapeutic temperature range and thus it is of utmost importance from the efficacy point of view of magnetic fluid hyperthermia (MFH.

  9. [Lymphotropic therapy for acute purulent odontogenic jaw periostitis].

    Science.gov (United States)

    Maĭborodin, I V; Lĭubarskiĭ, M S; Loĭko, E R; Sheplev, B V

    2003-01-01

    The structure of the gingival mucosa was studied by optic microscopy in patients with acute purulent odontogenic maxillary periostitis treated traditionally and receiving lymphotropic therapy. Lymphotropic administration of the antibiotic during 2 days resulted in less pronounced dilatation of the interstitial spaces and lymph vessels adjacent to the molars and higher counts of lymphocytes, monocytes, and macrophages. This indicated high efficiency of lymphotropic therapy of acute purulent maxillary periostitis for molars. Microcirculation parameters and tissue leukocyte cytogram in gingival mucosal tissue adjacent to the canines and premolars differed negligibly in patients treated by different methods.

  10. Core-Shell Nanoparticle-Enhanced Raman Spectroscopy.

    Science.gov (United States)

    Li, Jian-Feng; Zhang, Yue-Jiao; Ding, Song-Yuan; Panneerselvam, Rajapandiyan; Tian, Zhong-Qun

    2017-03-08

    Core-shell nanoparticles are at the leading edge of the hot research topics and offer a wide range of applications in optics, biomedicine, environmental science, materials, catalysis, energy, and so forth, due to their excellent properties such as versatility, tunability, and stability. They have attracted enormous interest attributed to their dramatically tunable physicochemical features. Plasmonic core-shell nanomaterials are extensively used in surface-enhanced vibrational spectroscopies, in particular, surface-enhanced Raman spectroscopy (SERS), due to the unique localized surface plasmon resonance (LSPR) property. This review provides a comprehensive overview of core-shell nanoparticles in the context of fundamental and application aspects of SERS and discusses numerous classes of core-shell nanoparticles with their unique strategies and functions. Further, herein we also introduce the concept of shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) in detail because it overcomes the long-standing limitations of material and morphology generality encountered in traditional SERS. We then explain the SERS-enhancement mechanism with core-shell nanoparticles, as well as three generations of SERS hotspots for surface analysis of materials. To provide a clear view for readers, we summarize various approaches for the synthesis of core-shell nanoparticles and their applications in SERS, such as electrochemistry, bioanalysis, food safety, environmental safety, cultural heritage, materials, catalysis, and energy storage and conversion. Finally, we exemplify about the future developments in new core-shell nanomaterials with different functionalities for SERS and other surface-enhanced spectroscopies.

  11. Hepatitis C virus has a genetically determined lymphotropism through co-receptor B7.2

    Science.gov (United States)

    Chen, Chia-Lin; Huang, Jeffrey Y.; Wang, Chun-Hsiang; Tahara, Stanley M; Zhou, Lin; Kondo, Yasuteru; Schechter, Joel; Su, Lishan; Lai, Michael M C.; Wakita, Takaji; Cosset, François-Loïc; Jung, Jae U; Machida, Keigo

    2017-01-01

    B-cell infection by hepatitis C virus (HCV) has been a controversial topic. To examine whether HCV has a genetically determined lymphotropism through a co-receptor specific for the infection by lymphotropic HCV, we established an infectious clone and chimeric virus of hepatotropic and lymphotropic HCV strains derived from an HCV-positive B-cell lymphoma. The viral envelope and 5′-UTR sequences of the lymphotropic HCV strain were responsible for the lymphotropism. Silencing of the virus sensor, RIGI, or overexpression of microRNA-122 promoted persistent viral replication in B cells. By cDNA library screening, we identified an immune cell-specific, co-stimulatory receptor B7.2 (CD86) as a co-receptor of lymphotropic HCV. Infection of B cells by HCV inhibited the recall reaction to antigen stimulation. Together, a co-receptor B7.2 enabled lymphotropic HCV to infect memory B cells, leading to inhibition of memory B-cell function and persistent HCV infection in HCV-infected hosts. PMID:28067225

  12. Lymphotropic antifilarial agents derived from closantel and chlorambucil.

    Science.gov (United States)

    Loiseau, P M; Bourass, J; Letourneux, Y

    1997-04-01

    New closantel and chlorambucil prodrugs expected to accumulate in the lymphatic system were evaluated on the filaria Molinema dessetae. The prodrugs of closantel had a delayed effect in vitro on the infective larvae compared to the free drug. The closantel prodrugs were less toxic in vivo than closantel itself. The most active prodrug after treatment at 200 mumol/kg by the oral route was the 1,3-dipalmitoyl-2-succinyl-glycerol-closantel. The macrofilaricidal delayed effect of closantel prodrugs was of interest to prevent anaphylactic shock. In vitro, chlorambucil was active on M. dessetae infective larvae with an IC50 of 26 microM. 1,3-Dipalmitoyl-2-chlorambucil-glycerol was slightly active while the addition of a thioether function between the drug and the lymphotropic ligand canceled the activity. However, no activity with chlorambucil and its prodrugs was observed in vivo. The lymphotropism of these prodrugs has now to be verified using comparative pharmacokinetics in serum and lymph to quantify the increase in drug concentration in lymph.

  13. Proanthocyanidins-Loaded Nanoparticles Enhance Dentin Degradation Resistance.

    Science.gov (United States)

    Fawzy, A S; Priyadarshini, B M; Selvan, S T; Lu, T B; Neo, J

    2017-07-01

    Previous studies reported that grapeseed extract (GSE), which is rich in proanthocyanidins (PAs), improves the biodegradation resistance of demineralized dentin. This study aimed to investigate the effect of a new GSE delivery strategy to demineralized dentin through loading into biodegradable polymer poly-[lactic-co-glycolic acid] (PLGA) nanoparticles on the biodegradation resistance in terms of structural stability and surface/bulk mechanical and biochemical properties with storage time in collagenase-containing solutions. GSE-loaded nanoparticles were synthetized by nanoprecipitation at PLGA/GSE (w/w) ratios of 100:75, 100:50, and 100:25 and characterized for their morphological/structural features, physicochemical characteristics, and drug loading, entrapment, and release. Nanoparticle suspensions in distilled water (12.5% w/v) were applied (1 min) to demineralized dentin specimens by simulating pulpal pressure. The nanoparticle delivery was investigated by scanning electron microscopy (SEM)/transmission electron microscopy (TEM), and the GSE release from the delivered nanoparticles was further characterized. The variations in surface and bulk mechanical properties were characterized in terms of reduced elastic-modulus, hardness, nanoindentation testing, and apparent elastic-modulus with a storage time up to 3 mo. Hydroxyproline release with exposure to collagenase up to 7 d was estimated. An etch-and-rinse dentin adhesive was applied to investigate the morphology of the resin-dentin interface after nanoparticle delivery. Treatment with the GSE-loaded nanoparticles enhanced the collagen fibril structural resistance, reflected from the TEM investigation, and improved the biomechanical and biochemical stability of demineralized dentin. Nanoparticles having PLGA/GSE of 100:75 (w/w) showed the highest cumulative GSE release and were associated with the best improvement in biodegradation resistance. TEM/SEM showed the ability of the nanoparticles to infiltrate

  14. Nanoparticle-enhanced synergistic HIFU ablation and transarterial chemoembolization for efficient cancer therapy

    Science.gov (United States)

    You, Yufeng; Wang, Zhigang; Ran, Haitao; Zheng, Yuanyi; Wang, Dong; Xu, Jinshun; Wang, Zhibiao; Chen, Yu; Li, Pan

    2016-02-01

    High-intensity focused ultrasound (HIFU) is being generally explored as a non-invasive therapeutic modality to treat solid tumors. However, the clinical use of HIFU for large and deep tumor-ablation applications such as hepatocellular carcinoma (HCC) is currently entangled with long treatment duration and high operating energy. This critical issue can be potentially resolved by the introduction of HIFU synergistic agents (SAs). Traditional SAs such as microbubbles and microparticles face the problem of large size, short cycle time, damage to mononuclear phagocytic system and unsatisfactory targeting efficiency. In this work, we have developed a facile and versatile nanoparticle-based HIFU synergistic cancer surgery enhanced by transarterial chemoembolization for high-efficiency HCC treatment based on elaborately designed Fe3O4-PFH/PLGA nanocapsules. Multifunctional Fe3O4-PFH/PLGA nanocapsules were administrated into tumor tissues via transarterial injection combined with Lipiodol to achieve high tumor accumulation because transarterial chemoembolization by Lipiodol could block the blood vessels. The high synergistic HIFU ablation effect was successfully achieved against HCC tumors based on the phase-transformation performance of the perfluorohexane (PFH) inner core in the composite nanocapsules, as systematically demonstrated in VX2 liver tumor xenograft in rabbits. Multifunctional Fe3O4-PFH/PLGA nanocapsules were also demonstrated as efficient contrast agents for ultrasound, magnetic resonance and photoacoustic tri-modality imagings, potentially applicable for imaging-guided HIFU synergistic surgery. Therefore, the elaborate integration of traditional transarterial chemoembolization with recently developed nanoparticle-enhanced HIFU cancer surgery could efficiently enhance the HCC cancer treatment outcome, initiating a new and efficient therapeutic protocol/modality for clinic cancer treatment.

  15. Imaging of human T-lymphotropic virus type I-associated chronic progressive myeloneuropathies

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    Alcindor, F. (Dept. of Neurology, State Univ. of New York, Health Science Center, Brooklyn, NY (United States)); Valderrama, R. (Dept. of Neurology, State Univ. of New York, Health Science Center, Brooklyn, NY (United States)); Canavaggio, M. (Abbott Labs., North Chicago, IL (United States)); Lee, H. (Abbott Labs., North Chicago, IL (United States)); Katz, A. (Dept. of Neurology, State Univ. of New York, Health Science Center, Brooklyn, NY (United States)); Montesinos, C. (Beth Israel Medical Center, Dept. of Neurology and Clinical Electrophysiology, New York, NY (United States)); Madrid, R.E. (New York State Office of Mental Retardation and Developmental Disabilities, Inst. for Basic Research in Developmental Disabilities, NY (United States)); Merino, R.R. (Beth Israel Medical Center, Dept. of Neurology and Clinical Electrophysiology, New York, NY (United States)); Pipia, P.A. (Dept. of Neurology, State Univ. of New York, Health Science Center, Brooklyn, NY (United States))

    1992-12-01

    We studied magnetic resonance imaging (MRI) of the head and cervical spine and CT of the head in 46 patients (14 men, 32 women) with chronic progressive myeloneuropathy. The findings were correlated with human T-lymphotropic virus type I (HTLV-I) serology, race, country of origin, and age. We found a female predominance of 2:1. Most patients were aged between 30 and 50 years, and most were Caribbean immigrants and black. There were 9 men and 17 women with blood antibody titers to HTLV-I and 7 mem and 15 women with cerebrospinal fluid (CSF) titers. All patients with virus or antibodies in blood or CSF were Caribbean immigrants or black. T2-weighted cranial MRI showed scattered areas of high signal intensity in the cerebral white matter, usually in the periventricular and subcortical areas, but not in the posterior cranial fossa. Cranial CT revealed periventricular low density areas, ventricular enlargement, and atrophy MRI of the cervical spine showed atrophy of the cord. Myelography was normal in all 15 patients examined. No imaging differences were observed between the HTLV-I-positive and -negative patients. These findings, although consistent with demyelination, are not specific. (orig.)

  16. Occult persistence and lymphotropism of hepatitis C virus infection

    Institute of Scientific and Technical Information of China (English)

    Tram NQ Pham; Tomasz I Michalak

    2008-01-01

    Recent discovery of occult hepatitis C virus (HCV)infection persisting after spontaneous or antiviral therapy-induced resolution of hepatitis C was made possible by the introduction of nucleic acid amplification assays capable of detecting HCV RNA at sensitivities superseding those offered by clinical tests. Although individuals with this seemingly silent HCV infection are usually anti-HCV antibody reactive and have normal liver function tests, occult HCV infection has also been reported in anti-HCV-negative individuals with persistently elevated liver enzymes of unknown etiology. Studies have shown that HCV RNA can persist for years in serum, iymphomononuciear cells and liver in the absence of clinical symptoms, although histological evidence of a mild inflammatory liver injury can be occasionally encountered. Furthermore, while HCV RNA can be detected in circulating lymphoid cells in approximately 30% of cases, a short-term culture under stimulatory conditions augments HCV replication in these cells allowing detection of virus in otherwise HCV-negative cases. HCV infects different immune cell subsets, including CD4+ and CD8+ T lymphocytes, B cells and monocytes. Studies employing cional sequencing and single-stranded conformational polymorphism analyses have revealed unique HCV variants residing in immune cells, further strengthening the notion of HCV lymphotropism. Overall, the data accumulated suggest that occult HCV infection is a common consequence of resolution of symptomatic hepatitis C and that examination of the cells of the immune system is an effective approach to diagnosis of HCV infection and its long-term persistence. Further work is required to fully realize pathogenic and epidemiological consequences of occult HCV persistence.

  17. Thermophysical Properties of Nanoparticle-Enhanced Ionic Liquids (NEILs) Heat-Transfer Fluids

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Elise B.; Visser, Ann E.; Bridges, Nicholas J.; Amoroso, Jake W.

    2013-06-20

    An experimental investigation was completed on nanoparticle enhanced ionic liquid heat transfer fluids as an alternative to conventional organic based heat transfer fluids (HTFs). These nanoparticle-based HTFs have the potential to deliver higher thermal conductivity than the base fluid without a significant increase in viscosity at elevated temperatures. The effect of nanoparticle morphology and chemistry on thermophysical properties was examined. Whisker shaped nanomaterials were found to have the largest thermal conductivity temperature dependence and were also less likely to agglomerate in the base fluid than spherical shaped nanomaterials.

  18. Convective heat transfer characters of nanoparticle enhanced latent functionally thermal fluid

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The latent heat of the microencapsulated phase change material(MPCM)increases the effective ther-mal capacity of latent functionally thermal fluid.However,researchers found that the heat transfer performance of such fluids was diminished due to the reduction of the low thermal conductivity of MPCM.For this reason,the nanoparticle enhanced latent functionally thermal fluids were formulated and the heat transfer behaviors of these fluids in a vertical circular tube at the laminar regime were conducted.The result showed that slurries containing 0.5% TiO2 nanoparticles by mass and 5%―20% MPCM by mass exhibited improved heat transfer rates in comparison with the conventional latent functionally thermal fluid and that the enhancement increased with the increasing MPCM concentration and up to 18.9% of the dimensionless wall temperature was reduced.

  19. Convective heat transfer characters of nanoparticle enhanced latent functionally thermal fluid

    Institute of Scientific and Technical Information of China (English)

    WANG Liang; LIN GuiPing; CHEN HaiSheng; DING YuLong

    2009-01-01

    The latent heat of the microencapsulated phase change material (MPCM) increases the effective ther-mal capacity of latent functionally thermal fluid. However, researchers found that the heat transfer performance of such fluids was diminished due to the reduction of the low thermal conductivity of MPCM. For this reason, the nanoparticle enhanced latent functionally thermal fluids were formulated and the heat transfer behaviors of these fluids in a vertical circular tube at the laminar regime were conducted. The result showed that slurries containing 0.5% TiO2 nanoparticles by mass and 5%-20% MPCM by mass exhibited improved heat transfer rates in comparison with the conventional latent functionally thermal fluid and that the enhancement increased with the increasing MPCM concentration and up to 18.9% of the dimensionless wall temperature was reduced.

  20. Coupling shell-isolated nanoparticle enhanced Raman spectroscopy with paper chromatography for multi-components on-site analysis.

    Science.gov (United States)

    Zhang, Kun; Qing, Jiang; Gao, Han; Ji, Ji; Liu, Baohong

    2017-01-01

    By coupling shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) with paper chromatography, two birds with one stone method were developed for simultaneous on-site separation and optical detection of multiple components. The established method features high sensitivity of plasmon-enhanced sensing strategies and sufficient temporal and spatial resolution of planar chromatographic techniques.

  1. Shell-isolated nanoparticle-enhanced Raman spectroscopy: principle and applications (Presentation Recording)

    Science.gov (United States)

    Li, Jian-Feng; Tian, Zhong-Qun

    2015-08-01

    Surface-enhanced Raman spectroscopy (SERS) is a powerful technique that yields fingerprint vibrational information with ultra-high sensitivity. However, only roughened Ag, Au and Cu surfaces can generate strong SERS effect. The lack of materials and morphology generality has severely limited the breadth of SERS practical applications on surface science, electrochemistry and catalysis. Shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) was therefore invented to break the long-standing limitation of SERS. In SHINERS, Au@SiO2 core-shell nanoparticles were rationally designed. The gold core acts as plasmonic antenna and encapsulated by an ultra-thin, uniform and pinhole-free silica shell, can provide high electromagnetic field to enhance the Raman signals of probed molecules. The inert silica shell acts as tunneling barrier prevents the core from interacting with the environment. SHINERS has already been applied to a number of challenging systems, such as hydrogen and CO on Pt(hkl) and Rh(hkl), which can't be realized by traditional SERS. Combining with electrochemical methods, we has investigated the adsorption processes of pyridine at the Au(hkl) single crystal/solution interface, and in-situ monitored the surface electro-oxidation at Au(hkl) electrodes. These pioneering studies demonstrate convincingly the ability of SHINERS in exploring correlations between structure and reactivity as well as in monitoring intermediates at the interfaces. SHINERS was also explored from semiconductor surface for industry, to living bacteria for life science, and to pesticide residue detection for food safety. The concept of shell-isolated nanoparticle-enhancement is being applied to other spectroscopies such as infrared absorption, sum frequency generation and fluorescence. Jian-Feng Li et al., Nature, 2010, 464, 392-395.

  2. Failure to demonstrate human T cell lymphotropic virus type I in multiple sclerosis patients

    DEFF Research Database (Denmark)

    Fugger, L; Morling, N; Ryder, L P;

    1990-01-01

    The polymerase chain reaction (PCR) technique was employed in searching for human T cell lymphotropic virus type I (HTLV-I) gag, env and pol sequences in samples of DNA prepared from two HTLV-I seropositive patients with tropical spastic paraparesis (TSP), the Swedish multiple sclerosis (MS...... and detection probes. In MS patients and healthy individuals, no signals were obtained with gag and env. In occasional experiments, weak signals were seen for the pol segment for a single MS patient and/or healthy individuals, but these signals were not reproducible in subsequent experiments. Thus, the present...

  3. Coated carbide drill performance under soluble coconut oil lubricant and nanoparticle enhanced MQL in drilling AISI P20

    Science.gov (United States)

    Jamil, N. A. M.; Azmi, A. I.; Fairuz, M. A.

    2016-02-01

    This research experimentally investigates the performance of a TiAlN coated carbide drill bit in drilling AISI P20 through two different kinds of lubricants, namely; soluble coconut oil (SCO) and nanoparticle-enhanced coconut oil (NECO) under minimum quantity lubrication system. The tool life and tool wear mechanism were studied using various cutting speeds of 50, 100 and 150 m/min with a constant feed of 0.01 mm/rev. Since the flank wear land was not regular along the cutting edge, the average flank wear (VB) was measured at several points using image analysis software. The drills were inspected using a scanning electron microscope to further elucidate the wear mechanism. The result indicates that drilling with the nanoparticle- enhanced lubricant was better in resisting the wear and improving the drill life to some extent

  4. Evaluation of the microscopic dose enhancement for nanoparticle-enhanced Auger therapy

    Science.gov (United States)

    Sung, Wonmo; Jung, Seongmoon; Ye, Sung-Joon

    2016-11-01

    The aim of this study is to investigate the dosimetric characteristics of nanoparticle-enhanced Auger therapy. Monte Carlo (MC) simulations were performed to assess electron energy spectra and dose enhancement distributions around a nanoparticle. In the simulations, two types of nanoparticle structures were considered: nanoshell and nanosphere, both of which were assumed to be made of one of five elements (Fe, Ag, Gd, Au, and Pt) in various sizes (2-100 nm). Auger-electron emitting radionuclides (I-125, In-111, and Tc-99m) were simulated within a nanoshell or on the surface of a nanosphere. For the most promising combination of Au and I-125, the maximum dose enhancement was up to 1.3 and 3.6 for the nanoshell and the nanosphere, respectively. The dose enhancement regions were restricted within 20-100 nm and 0-30 nm distances from the surface of Au nanoshell and nanosphere, respectively. The dose enhancement distributions varied with sizes of nanoparticles, nano-elements, and radionuclides and thus should be carefully taken into account for biological modeling. If the nanoparticles are accumulated in close proximity to the biological target, this new type of treatment can deliver an enhanced microscopic dose to the target (e.g. DNA). Therefore, we conclude that Auger therapy combined with nanoparticles could have the potential to provide a better therapeutic effect than conventional Auger therapy alone.

  5. Silver nanoparticle enhanced immunoassays: one step real time kinetic assay for insulin in serum.

    Science.gov (United States)

    Lochner, Nina; Lobmaier, Christina; Wirth, Michael; Leitner, Alfred; Pittner, Fritz; Gabor, Franz

    2003-11-01

    Silver nanoparticle enhanced fluorescence is introduced as an alternative method to surface plasmon resonance techniques for real time monitoring of biorecognitive interactions or immunoassays. This method relies on the phenomenon that an electromagnetic near field is generated upon illumination on the surface of silver nanoparticles. The interaction of this field with nearby fluorophores results in fluorescence enhancement. Thus, fluorophores in the bulk solution can be discriminated from surface bound fluorophores. Anti-insulin-antibodies were immobilized on the surface of silver colloids in the following order: A ready to use microplate was prepared by bottom up coating with layers of aminosilane, silver nanoparticles, Fc-recognizing F(ab)(2)-fragments and anti-insulin-antibodies. At equilibrium conditions fluorescein-labeled insulin could only be detected in the presence of the colloid; the detection limit was 250 nM, and a fourfold increase in fluorescence was observed upon real time monitoring. The competitive assay of labeled and unlabeled insulin revealed a working range of 10-200 nM insulin in serum. The rapid single step immunoassay is easy to perform even in microplate format, its sensitivity is comparable to ELISA techniques, and offers broad application for real time monitoring of molecular recognitive processes.

  6. Monte Carlo and analytic simulations in nanoparticle-enhanced radiation therapy

    Directory of Open Access Journals (Sweden)

    Paro AD

    2016-09-01

    Full Text Available Autumn D Paro,1 Mainul Hossain,2 Thomas J Webster,1,3,4 Ming Su1,4 1Department of Chemical Engineering, Northeastern University, Boston, MA, USA; 2NanoScience Technology Center and School of Electrical Engineering and Computer Science, University of Central Florida, Orlando, Florida, USA; 3Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia; 4Wenzhou Institute of Biomaterials and Engineering, Chinese Academy of Science, Wenzhou Medical University, Zhejiang, People’s Republic of China Abstract: Analytical and Monte Carlo simulations have been used to predict dose enhancement factors in nanoparticle-enhanced X-ray radiation therapy. Both simulations predict an increase in dose enhancement in the presence of nanoparticles, but the two methods predict different levels of enhancement over the studied energy, nanoparticle materials, and concentration regime for several reasons. The Monte Carlo simulation calculates energy deposited by electrons and photons, while the analytical one only calculates energy deposited by source photons and photoelectrons; the Monte Carlo simulation accounts for electron–hole recombination, while the analytical one does not; and the Monte Carlo simulation randomly samples photon or electron path and accounts for particle interactions, while the analytical simulation assumes a linear trajectory. This study demonstrates that the Monte Carlo simulation will be a better choice to evaluate dose enhancement with nanoparticles in radiation therapy. Keywords: nanoparticle, dose enhancement, Monte Carlo simulation, analytical simulation, radiation therapy, tumor cell, X-ray 

  7. Fast and sensitive detection of ochratoxin A in red wine by nanoparticle-enhanced SPR.

    Science.gov (United States)

    Karczmarczyk, Aleksandra; Reiner-Rozman, Ciril; Hageneder, Simone; Dubiak-Szepietowska, Monika; Dostálek, Jakub; Feller, Karl-Heinz

    2016-09-21

    Herein, we present a fast and sensitive biosensor for detection of Ochratoxin A (OTA) in a red wine that utilizes gold nanoparticle-enhanced surface plasmon resonance (SPR). By combining an indirect competitive inhibition immunoassay and signal enhancement by secondary antibodies conjugated with gold nanoparticles (AuNPs), highly sensitive detection of low molecular weight compounds (such as OTA) was achieved. The reported biosensor allowed for OTA detection at concentrations as low as 0.75 ng mL(-1) and its limit of detection was improved by more than one order of magnitude to 0.068 ng mL(-1) by applying AuNPs as a signal enhancer. The study investigates the interplay of size of AuNPs and affinity of recognition elements affecting the efficiency of the signal amplification strategy based on AuNP. Furthermore, we observed that the presence of polyphenolic compounds in wine samples strongly interferes with the affinity binding on the surface. To overcome this limitation, a simple pre-treatment of the wine sample with the binding agent poly(vinylpyrrolidone) (PVP) was successfully applied.

  8. Gold nanoparticles enhance the radiation therapy of a murine squamous cell carcinoma

    Science.gov (United States)

    Hainfeld, James F.; Avraham Dilmanian, F.; Zhong, Zhong; Slatkin, Daniel N.; Kalef-Ezra, John A.; Smilowitz, Henry M.

    2010-06-01

    The purpose of this study is to test the hypothesis that gold nanoparticle (AuNP, nanogold)-enhanced radiation therapy (nanogold radiation therapy, NRT) is efficacious when treating the radiation resistant and highly aggressive mouse head and neck squamous cell carcinoma model, SCCVII, and to identify parameters influencing the efficacy of NRT. Subcutaneous (sc) SCCVII leg tumors in mice were irradiated with x-rays at the Brookhaven National Laboratory (BNL) National Synchrotron Light Source (NSLS) with and without prior intravenous (iv) administration of AuNPs. Variables studied included radiation dose, beam energy, temporal fractionation and hyperthermia. AuNP-mediated NRT was shown to be effective for the sc SCCVII model. AuNPs were more effective at 42 Gy than at 30 Gy (both at 68 keV median beam energy) compared to controls without gold. Similarly, at 157 keV median beam energy, 50.6 Gy NRT was more effective than 44 Gy NRT. At the same radiation dose (~42 Gy), 68 keV was more effective than 157 keV. Hyperthermia and radiation therapy (RT) were synergistic and AuNPs enhanced this synergy, thereby further reducing TCD50 s (tumor control dose 50%) and increasing long-term survivals. It is concluded that gold nanoparticles enhance the radiation therapy of a radioresistant mouse squamous cell carcinoma. The data show that radiation dose, energy and hyperthermia influence efficacy and better define the potential utility of gold nanoparticles for cancer x-ray therapy.

  9. Gold Nanoparticles Enhance the Radiation Therapy of a Murine Squamous Cell Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Hainfeld, J.F.; Zhong, Z.; Dilmanian, F.A.; Slatkin, D.N.; Kalef-Ezra, J.A.; Smilowitz, H.

    2010-05-12

    The purpose of this study is to test the hypothesis that gold nanoparticle (AuNP, nanogold)-enhanced radiation therapy (nanogold radiation therapy, NRT) is efficacious when treating the radiation resistant and highly aggressive mouse head and neck squamous cell carcinoma model, SCCVII, and to identify parameters influencing the efficacy of NRT. Subcutaneous (sc) SCCVII leg tumors in mice were irradiated with x-rays at the Brookhaven National Laboratory (BNL) National Synchrotron Light Source (NSLS) with and without prior intravenous (iv) administration of AuNPs. Variables studied included radiation dose, beam energy, temporal fractionation and hyperthermia. AuNP-mediated NRT was shown to be effective for the sc SCCVII model. AuNPs were more effective at 42 Gy than at 30 Gy (both at 68 keV median beam energy) compared to controls without gold. Similarly, at 157 keV median beam energy, 50.6 Gy NRT was more effective than 44 Gy NRT. At the same radiation dose (42 Gy), 68 keV was more effective than 157 keV. Hyperthermia and radiation therapy (RT) were synergistic and AuNPs enhanced this synergy, thereby further reducing TCD50 s (tumor control dose 50%) and increasing long-term survivals. It is concluded that gold nanoparticles enhance the radiation therapy of a radioresistant mouse squamous cell carcinoma. The data show that radiation dose, energy and hyperthermia influence efficacy and better define the potential utility of gold nanoparticles for cancer x-ray therapy.

  10. Hepatitis C virus lymphotropism and peculiar immunological phenotype: Effects on natural history and antiviral therapy

    Institute of Scientific and Technical Information of China (English)

    Paolo Conca; Giovanni Tarantino

    2009-01-01

    Hepatitis C virus (HCV) has been recognized to be both a hepato- and lymphotropic virus. HCV lymphotropism represents an essential lap in the pathogenesis of virusrelated autoimmune and lymphoproliferative disorders, ranging from clonal expansion of B-cells with organ-and non-organ-specific autoantibody production up step-by-step model of B-cell lymphomagenesis, where the intermediated mixed cryoglobulinemia could be considered as a stage of suppressible antigen-driven lymphoproliferation. HCV infection of lymphoid cells could set up privileged reservoirs able to interfere with the host viral clearance efficiency and may be implicated in viral recurrence after apparently successful antiviral therapy. The HCV long-lasting extrahepatic replicative state generates an abnormal systemic immunological response, easily detectable by searching simple laboratory and clinical parameters, mainly represented by vasculitis-like skin features and hypocomplementemia.The presence or absence of this hypersensitivity pattern seems to correlate with the antiviral response and could be identified as a novel immunological cofactor. Further research is required to fully verify the real impact on therapeutic choice/regimen.

  11. Reduced cell turnover in lymphocytic monkeys infected by human T-lymphotropic virus type 1.

    Science.gov (United States)

    Debacq, Christophe; Héraud, Jean-Michel; Asquith, Becca; Bangham, Charles; Merien, Fabrice; Moules, Vincent; Mortreux, Franck; Wattel, Eric; Burny, Arsène; Kettmann, Richard; Kazanji, Mirdad; Willems, Luc

    2005-11-17

    Understanding cell dynamics in animal models have implications for therapeutic strategies elaborated against leukemia in human. Quantification of the cell turnover in closely related primate systems is particularly important for rare and aggressive forms of human cancers, such as adult T-cell leukemia. For this purpose, we have measured the death and proliferation rates of the CD4+ T lymphocyte population in squirrel monkeys (Saimiri sciureus) infected by human T-lymphotropic virus type 1 (HTLV-1). The kinetics of in vivo bromodeoxyuridine labeling revealed no modulation of the cell turnover in HTLV-1-infected monkeys with normal CD4 cell counts. In contrast, a substantial decrease in the proliferation rate of the CD4+ T population was observed in lymphocytic monkeys (e.g. characterized by excessive proportions of CD4+ T lymphocytes and by the presence of abnormal flower-like cells). Unexpectedly, onset of HTLV-associated leukemia thus occurs in the absence of increased CD4+ T-cell proliferation. This dynamics significantly differs from the generalized activation of the T-cell turnover induced by other primate lymphotropic viruses like HIV and SIV.

  12. Molecular investigation of the evolutionary history and diversity of primate T-lymphotropic virus types 1 and 3

    NARCIS (Netherlands)

    Van Dooren, Sonia Jeanne Albertine

    2005-01-01

    The Primate T-lymphotropic viruses (PTLV) comprise a group of complex retroviruses that infect both humans (HTLV) and simians (STLV) and have been associated with leukaemia or lymphoma and with neurological disorders. PTLVs have a peculiar replication strategy: their way of life is mainly determined

  13. Molecular investigation of the evolutionary history and diversity of primate T-lymphotropic virus types 1 and 3

    NARCIS (Netherlands)

    Van Dooren, Sonia Jeanne Albertine

    2005-01-01

    The Primate T-lymphotropic viruses (PTLV) comprise a group of complex retroviruses that infect both humans (HTLV) and simians (STLV) and have been associated with leukaemia or lymphoma and with neurological disorders. PTLVs have a peculiar replication strategy: their way of life is mainly determined

  14. Amorphous silica nanoparticles enhance cross-presentation in murine dendritic cells

    Energy Technology Data Exchange (ETDEWEB)

    Hirai, Toshiro [Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Yoshioka, Yasuo, E-mail: yasuo@phs.osaka-u.ac.jp [Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Takahashi, Hideki; Ichihashi, Ko-ichi; Yoshida, Tokuyuki; Tochigi, Saeko [Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nagano, Kazuya [Laboratory of Biopharmaceutical Research, National Institute of Biomedical Innovation, 7-6-8 Saitoasagi, Ibaraki, Osaka 567-0085 (Japan); Abe, Yasuhiro [Cancer Biology Research Center, Sanford Research/USD, 2301 E. 60th Street N, Sioux Falls, SD 57104 (United States); Kamada, Haruhiko; Tsunoda, Shin-ichi [Laboratory of Biopharmaceutical Research, National Institute of Biomedical Innovation, 7-6-8 Saitoasagi, Ibaraki, Osaka 567-0085 (Japan); The Center for Advanced Medical Engineering and Informatics, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Nabeshi, Hiromi [Division of Foods, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501 (Japan); Yoshikawa, Tomoaki [Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Tsutsumi, Yasuo, E-mail: ytsutsumi@phs.osaka-u.ac.jp [Laboratory of Toxicology and Safety Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Laboratory of Biopharmaceutical Research, National Institute of Biomedical Innovation, 7-6-8 Saitoasagi, Ibaraki, Osaka 567-0085 (Japan); The Center for Advanced Medical Engineering and Informatics, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer Silica nanoparticles enhanced cross-presentation. Black-Right-Pointing-Pointer Silica nanoparticles induced endosomal release of exogenous antigens. Black-Right-Pointing-Pointer Silica nanoparticle-induced cross-presentation was mediated by scavenger receptors. Black-Right-Pointing-Pointer Surface-modification may enable the manufacture of safer silica nanoparticles. -- Abstract: Nanomaterials (NMs) exhibit unique physicochemical properties and innovative functions, and they are increasingly being used in a wide variety of fields. Ensuring the safety of NMs is now an urgent task. Recently, we reported that amorphous silica nanoparticles (nSPs), one of the most widely used NMs, enhance antigen-specific cellular immune responses and may therefore aggravate immune diseases. Thus, to ensure the design of safer nSPs, investigations into the effect of nSPs on antigen presentation in dendritic cells, which are central orchestrators of the adaptive immune response, are now needed. Here, we show that nSPs with diameters of 70 and 100 nm enhanced exogenous antigen entry into the cytosol from endosomes and induced cross-presentation, whereas submicron-sized silica particles (>100 nm) did not. Furthermore, we show that surface modification of nSPs suppressed cross-presentation. Although further studies are required to investigate whether surface-modified nSPs suppress immune-modulating effects in vivo, the current results indicate that appropriate regulation of the characteristics of nSPs, such as size and surface properties, will be critical for the design of safer nSPs.

  15. HUMAN T-LYMPHOTROPIC VIRUS 1 (HTLV-1 AND HUMAN T-LYMPHOTROPIC VIRUS 2 (HTLV-2: GEOGRAPHICAL RESEARCH TRENDS AND COLLABORATION NETWORKS (1989-2012

    Directory of Open Access Journals (Sweden)

    Gregorio GONZÁLEZ-ALCAIDE

    2016-01-01

    Full Text Available Publications are often used as a measure of research work success. Human T-lymphotropic virus (HTLV type 1 and 2 are human retroviruses, which were discovered in the early 1980s, and it is estimated that 15-20 million people are infected worldwide. This article describes a bibliometric review and a coauthorship network analysis of literature on HTLV indexed in PubMed in a 24-year period. A total of 7,564 documents were retrieved, showing a decrease in the number of documents from 1996 to 2007. HTLV manuscripts were published in 1,074 journals. Japan and USA were the countries with the highest contribution in this field (61% followed by France (8%. Production ranking changed when the number of publications was normalized by population (Dominican Republic and Japan, by gross domestic product (Guinea-Bissau and Gambia, and by gross national income per capita (Brazil and Japan. The present study has shed light on some of the defining features of scientific collaboration performed by HTLV research community, such as the existence of core researchers responsible for articulating the development of research in the area, facilitating wider collaborative relationships and the integration of new authors in the research groups.

  16. Diffuse Large B-Cell Lymphoma in Human T-Lymphotropic Virus Type 1 Carriers

    Directory of Open Access Journals (Sweden)

    Brady E. Beltran

    2012-01-01

    Full Text Available We describe the clinical and pathological characteristics of seven patients who were human T-lymphotropic virus type 1 (HTLV-1 carriers and had a pathological diagnosis of de novo diffuse large B-cell lymphoma. Interestingly, three of our cases showed positive expression of Epstein-Barr-virus, (EBV- encoded RNA within the tumor cells indicating a possible interaction between these two viruses. Furthermore, our three EBV-positive cases presented with similar clinical characteristics such as early clinical stage and low-risk indices. To the best of our knowledge, this is the first case series describing the characteristics of HTLV-1-positive DLBCL patients. The potential relationship between HTLV-1 and EBV should be further explored.

  17. Activation of porcine cytomegalovirus, but not porcine lymphotropic herpesvirus, in pig-to-baboon xenotransplantation.

    Science.gov (United States)

    Mueller, Nicolas J; Livingston, Christine; Knosalla, Christoph; Barth, Rolf N; Yamamoto, Shin; Gollackner, Bernd; Dor, Frank J M F; Buhler, Leo; Sachs, David H; Yamada, Kazuhiko; Cooper, David K C; Fishman, Jay A

    2004-05-01

    Tissue-invasive disease due to porcine cytomegalovirus (PCMV) has been demonstrated after pig-to-baboon solid-organ xenotransplantation. Porcine lymphotropic herpesvirus (PLHV)-1 is associated with B cell proliferation and posttransplant lymphoproliferative disorder after allogeneic bone marrow transplantation in swine but has not been observed in pig-to-primate xenotransplantation. Activation of PCMV and PLHV-1 was investigated in 22 pig-to-baboon xenotransplants by use of quantitative polymerase chain reaction. PCMV was found in all xenografts; increased viral replication occurred in 68% of xenografts during immunosuppression. PLHV-1 was found in 12 xenografts (55%); no increases in viral replication occurred during immunosuppression. Control immunosuppressed swine coinfected with PCMV and PLHV-1 had activation of PCMV but not PLHV-1. PCMV, but not PLHV-1, is activated in solid-organ xenotransplantation.

  18. Failure to demonstrate human T cell lymphotropic virus type I in multiple sclerosis patients

    DEFF Research Database (Denmark)

    Fugger, L; Morling, N; Ryder, L P

    1990-01-01

    The polymerase chain reaction (PCR) technique was employed in searching for human T cell lymphotropic virus type I (HTLV-I) gag, env and pol sequences in samples of DNA prepared from two HTLV-I seropositive patients with tropical spastic paraparesis (TSP), the Swedish multiple sclerosis (MS......) patients who recently have been reported to be PCR-positive for HTLV-I gag and env sequences, and eight healthy individuals. Precautions were taken in order to reduce the risk of cross-contamination in the PCR. In the two TSP patients strong signals were obtained with gag, env and pol amplification primers...... data do not confirm the presence of HTLV-I sequences in MS patients....

  19. Nano-particle enhanced impedimetric biosensor for detection of foodborne pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Kim, G [National Institute of Agricultural Engineering, 249 Seodun-dong, Suwon, Republic of Korea, 441-100 (Korea, Republic of); Om, A S [Department of Food and Nutrient, Hanyang University, 17 Haengdang-dong, Seoul, Republic of Korea, 133-791 (Korea, Republic of); Mun, J H [Department of Food and Nutrient, Hanyang University, 17 Haengdang-dong, Seoul, Republic of Korea, 133-791 (Korea, Republic of)

    2007-03-15

    Recent outbreaks of foodborne illness have been increased the need for rapid and sensitive methods for detection of these pathogens. Conventional methods for pathogens detection and identification involve prolonged multiple enrichment steps. Even though some immunological rapid assays are available, these assays still need enrichment steps result in delayed detection. Biosensors have shown great potential for rapid detection of foodborne pathogens. They are capable of direct monitoring the antigen-antibody reactions in real time. Among the biosensors, impedimetric biosensors have been widely adapted as an analysis tool for the study of various biological binding reactions because of their high sensitivity and reagentless operation. In this study a nanoparticle-enhanced impedimetric biosensor for Salmonella enteritidis detection was developed which detected impedance changes caused by the attachment of the cells to the anti-Salmonella antibodies immobilized on interdigitated gold electrodes. Successive immobilization of neutravidin followed by anti-Salmonella antibodies was performed to the sensing area to create a biological detection surface. To enhance the impedance responses generated by antigen-antibody reactions, anti-Salmonella antibody conjugated nanoparticles were introduced on the sensing area. Using a portable impedance analyzer, the impedance across the interdigital electrodes was measured after the series of antigen-antibody bindings. Bacteria cells present in solution attached to capture antibodies and became tethered to the sensor surface. Attached bacteria cells changed the dielectric constant of the media between the electrodes thereby causing a change in measured impedance. Optimum input frequency was determined by analyzing frequency characteristics of the biosensor over ranges of applied frequencies from 10 Hz to 400 Hz. At 100 Hz of input frequency, the biosensor was most sensitive to the changes of the bacteria concentration and this frequency

  20. Nano-particle enhanced impedimetric biosensor for detedtion of foodborne pathogens

    Science.gov (United States)

    Kim, G.; Om, A. S.; Mun, J. H.

    2007-03-01

    Recent outbreaks of foodborne illness have been increased the need for rapid and sensitive methods for detection of these pathogens. Conventional methods for pathogens detection and identification involve prolonged multiple enrichment steps. Even though some immunological rapid assays are available, these assays still need enrichment steps result in delayed detection. Biosensors have shown great potential for rapid detection of foodborne pathogens. They are capable of direct monitoring the antigen-antibody reactions in real time. Among the biosensors, impedimetric biosensors have been widely adapted as an analysis tool for the study of various biological binding reactions because of their high sensitivity and reagentless operation. In this study a nanoparticle-enhanced impedimetric biosensor for Salmonella enteritidis detection was developed which detected impedance changes caused by the attachment of the cells to the anti-Salmonella antibodies immobilized on interdigitated gold electrodes. Successive immobilization of neutravidin followed by anti-Salmonella antibodies was performed to the sensing area to create a biological detection surface. To enhance the impedance responses generated by antigen-antibody reactions, anti-Salmonella antibody conjugated nanoparticles were introduced on the sensing area. Using a portable impedance analyzer, the impedance across the interdigital electrodes was measured after the series of antigen-antibody bindings. Bacteria cells present in solution attached to capture antibodies and became tethered to the sensor surface. Attached bacteria cells changed the dielectric constant of the media between the electrodes thereby causing a change in measured impedance. Optimum input frequency was determined by analyzing frequency characteristics of the biosensor over ranges of applied frequencies from 10 Hz to 400 Hz. At 100 Hz of input frequency, the biosensor was most sensitive to the changes of the bacteria concentration and this frequency

  1. THE POTENTIAL OF NANOPARTICLE ENHANCED IONIC LIQUIDS (NEILS) AS ADVANCED HEAT TRANSFER FLUIDS

    Energy Technology Data Exchange (ETDEWEB)

    Fox, E.; Bridges, N.; Visser, A.

    2011-09-14

    Interest in capturing the energy of the sun is rising as demands for renewable energy sources increase. One area of developing research is the use of concentrating solar power (CSP), where the solar energy is concentrated by using mirrors to direct the sunlight towards a collector filled with a heat transfer fluid (HTF). The HTF transfers the collected energy into pressurized steam, which is used to generate energy. The greater the energy collected by the HTF, the more efficent the electrical energy production is, thus the overall efficiency is controlled by the thermal fluid. Commercial HTFs such as Therminol{reg_sign} (VP-1), which is a blend of biphenyl and diphenyl oxide, have a significant vapor pressure, especially at elevated temperatures. In order for these volatile compounds to be used in CSP systems, the system either has to be engineered to prevent the phase change (i.e., volatilization and condensation) through pressurization of the system, or operate across the phase change. Over thirty years ago, a class of low-melting organic compounds were developed with negligible vapor pressure. These compounds are referred to as ionic liquids (ILs), which are organic-based compounds with discrete charges that cause a significant decrease in their vapor pressure. As a class, ILs are molten salts with a melting point below 100 C and can have a liquidus range approaching 400 C, and in several cases freezing points being below 0 C. Due to the lack of an appreciable vapor pressure, volatilization of an IL is not possible at atmospheric pressure, which would lead to a simplification of the design if used as a thermal fluid and for energy storage materials. Though the lack of a vapor pressure does not make the use of ILs a better HTF, the lack of a vapor pressure is a compliment to their higher heat capacity, higher volummetric density, and thus higher volumetric heat capacity. These favorable physical properties give ILs a pontential advantage over the current commerically used thermal fluids. Also within the past decade nanofluids have gained attention for thermal conductivity enhancment of fluids, but little analysis has been completed on the heat capacity effects of the nanoparticle addition. The idea of ILs or nanofluids as a HTF is not new, as there are several references that have proposed the idea. However, the use of ionic liquid nanofluids containing nanomaterials other than carbon nanotubes has never before been studied. Here, for the first time, nano-particle enhanced ILs (NEILs) have been shown to increase the heat capacity of the IL with no adverse side effects to the ILs thermal stability and, only at high nanoparticle loading, are the IL physical properties affected. An increase of volumetric heat capacity translates into a better heat transfer fluid as more energy is stored per volumetric unit in the solar concentrating section, thus more efficency in increased steam pressure. Results show that the properties of the NEIL are highly dependant on the suspended nanomaterial and careful materials selection is required to fully optimize the nanofluid properties.

  2. Comparative performances of serologic and molecular assays for detecting human T lymphotropic virus type 1 and type 2 (HTLV-1 and HTLV-2 in patients infected with human immunodeficiency virus type 1 (HIV-1

    Directory of Open Access Journals (Sweden)

    Karoline Rodrigues Campos

    Full Text Available ABSTRACT The present study evaluated several techniques currently available (commercial kits and in-house assays for diagnosing human T lymphotropic viruses types 1 and 2 in two groups of patients enrolled at HIV/AIDS specialized care services in São Paulo: Group 1 (G1, n = 1608, 1237 male/371 female, median age 44.3 years old, majority using highly active antiretroviral therapy (HAART; G2, n = 1383, 930 male/453 female, median age of 35.6 years old, majority HAART naïve. Enzyme immunoassays [(EIA Murex and Gold ELISA] were employed for human T lymphotropic viruses types 1 and 2 screening; Western blotting (WB, INNO-LIA (LIA, real-time PCR pol (qPCR, and nested-PCR-RFLP (tax were used to confirm infection. Samples were considered human T lymphotropic viruses types 1 and 2 positive when there was reactivity using at least one of the four confirmatory assays. By serological screening, 127/2991 samples were positive or borderline, and human T lymphotropic virus infection was confirmed in 108 samples (three EIA-borderline: 56 human T lymphotropic virus type 1 [G1 (27 + G2 (29]; 45 human T lymphotropic virus type 2 [G1 (21 + G2 (24]; one human T lymphotropic virus type 1 + human T lymphotropic virus type 2 (G2; six human T lymphotropic virus [G1 (2 + G2 (4]. Although there were differences in group characteristics, human T lymphotropic viruses types 1 and 2 prevalence was similar [3.1% (G1 and 4.2% (G2, p = 0.113]. The overall sensitivities of LIA, WB, qPCR, and PCR-RFLP were 97.2%, 82.4%, 68.9%, and 68.4%, respectively, with some differences among groups, likely due to the stage of human T lymphotropic virus infection and/or HAART duration. Indeterminate immunoblotting results were detected in G2, possibly due to the seroconversion period. Negative results in molecular assays could be explained by the use of HAART, the occurrence of defective provirus and/or the low circulating proviral load. In conclusion, when determining the human T

  3. Human T Lymphotropic Virus Type 1 (HTLV-1: Molecular Biology and Oncogenesis

    Directory of Open Access Journals (Sweden)

    Patrick L. Green

    2010-09-01

    Full Text Available Human T lymphotropic viruses (HTLVs are complex deltaretroviruses that do not contain a proto-oncogene in their genome, yet are capable of transforming primary T lymphocytes both in vitro and in vivo. There are four known strains of HTLV including HTLV type 1 (HTLV-1, HTLV-2, HTLV-3 and HTLV-4. HTLV-1 is primarily associated with adult T cell leukemia (ATL and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP. HTLV-2 is rarely pathogenic and is sporadically associated with neurological disorders. There have been no diseases associated with HTLV-3 or HTLV-4 to date. Due to the difference in the disease manifestation between HTLV-1 and HTLV-2, a clear understanding of their individual pathobiologies and the role of various viral proteins in transformation should provide insights into better prognosis and prevention strategies. In this review, we aim to summarize the data accumulated so far in the transformation and pathogenesis of HTLV-1, focusing on the viral Tax and HBZ and citing appropriate comparisons to HTLV-2.

  4. Sexual transmission of human T-cell lymphotropic virus type 1

    Directory of Open Access Journals (Sweden)

    Arthur Paiva

    2014-06-01

    Full Text Available Human T-cell lymphotropic virus type 1 (HTLV-1 is endemic in many parts of the world and is primarily transmitted through sexual intercourse or from mother to child. Sexual transmission occurs more efficiently from men to women than women to men and might be enhanced by sexually transmitted diseases that cause ulcers and result in mucosal ruptures, such as syphilis, herpes simplex type 2 (HSV-2, and chancroid. Other sexually transmitted diseases might result in the recruitment of inflammatory cells and could increase the risk of HTLV-1 acquisition and transmission. Additionally, factors that are associated with higher transmission risks include the presence of antibodies against the viral oncoprotein Tax (anti-Tax, a higher proviral load in peripheral blood lymphocytes, and increased cervicovaginal or seminal secretions. Seminal fluid has been reported to increase HTLV replication and transmission, whereas male circumcision and neutralizing antibodies might have a protective effect. Recently, free virions were discovered in plasma, which reveals a possible new mode of HTLV replication. It is unclear how this discovery might affect the routes of HTLV transmission, particularly sexual transmission, because HTLV transmission rates are significantly higher from men to women than women to men.

  5. Possible etiologies for tropical spastic paraparesis and human T lymphotropic virus I-associated myelopathy

    Directory of Open Access Journals (Sweden)

    V. Zaninovic'

    2004-01-01

    Full Text Available The epidemiology of tropical spastic paraparesis/human T lymphotropic virus I (HTLV-I-associated myelopathy (TSP/HAM is frequently inconsistent and suggests environmental factors in the etiology of these syndromes. The neuropathology corresponds to a toxometabolic or autoimmune process and possibly not to a viral disease. Some logical hypotheses about the etiology and physiopathology of TSP and HAM are proposed. Glutamate-mediated excitotoxicity, central distal axonopathies, cassava, lathyrism and cycad toxicity may explain most cases of TSP. The damage caused to astrocytes and to the blood-brain barrier by HTLV-I plus xenobiotics may explain most cases of HAM. Analysis of the HTLV-I/xenobiotic ratio clarifies most of the paradoxical epidemiology of TSP and HAM. Modern neurotoxicology, neuroimmunology and molecular biology may explain the neuropathology of TSP and HAM. It is quite possible that there are other xenobiotics implicated in the etiology of some TSP/HAMs. The prevention of these syndromes appears to be possible today.

  6. Human T-lymphotropic viruses (HTLV) in England and Wales, 2004 to 2013: testing and diagnoses.

    Science.gov (United States)

    Ireland, Georgina; Croxford, Sara; Tosswill, Jennifer; Raghu, Rajani; Davison, Katy; Hewitt, Patricia; Simmons, Ruth; Taylor, Graham

    2017-05-18

    Human T-lymphotropic virus (HTLV) infection has been under enhanced surveillance in England and Wales since 2002, however, little is known about testing patterns. Using data from two surveillance systems held at Public Health England, we described HTLV antibody testing patterns between 2008 and 2013 and the demographic and clinical characteristics of persons diagnosed with HTLV in England and Wales between 2004 and 2013. An increase in HTLV testing was observed in England between 2008 and 2013 (3,581 to 7,130). Most tests (82%; 7,597/9,302) occurred within secondary care, 0.5% (48/9,302) of persons were reactive for HTLV antibodies and 0.3% (27/9,302) were confirmed positive. Increasing age and female sex were predictors of a reactive HTLV screen and confirmed diagnosis. Testing in primary care including sexual health and antenatal services was infrequent. Between 2004 and 2013, 858 people were diagnosed with HTLV, most of whom were female (65%; 549/851), of black Caribbean ethnicity (60%), not born in the United Kingdom (72%; 369/514) and asymptomatic at diagnosis (45%; 267/595). Despite increased testing, the epidemiology and clinical features of those diagnosed with HTLV have remained consistent. Apart from donor screening, testing for HTLV infection remains uncommon, except to diagnose associated disease. This article is copyright of The Authors, 2017.

  7. Human T-lymphotropic Virus Type 1-infected Cells Secrete Exosomes That Contain Tax Protein*

    Science.gov (United States)

    Jaworski, Elizabeth; Narayanan, Aarthi; Van Duyne, Rachel; Shabbeer-Meyering, Shabana; Iordanskiy, Sergey; Saifuddin, Mohammed; Das, Ravi; Afonso, Philippe V.; Sampey, Gavin C.; Chung, Myung; Popratiloff, Anastas; Shrestha, Bindesh; Sehgal, Mohit; Jain, Pooja; Vertes, Akos; Mahieux, Renaud; Kashanchi, Fatah

    2014-01-01

    Human T-lymphotropic virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia and HTLV-1-associated myelopathy/tropical spastic paraparesis. The HTLV-1 transactivator protein Tax controls many critical cellular pathways, including host cell DNA damage response mechanisms, cell cycle progression, and apoptosis. Extracellular vesicles called exosomes play critical roles during pathogenic viral infections as delivery vehicles for host and viral components, including proteins, mRNA, and microRNA. We hypothesized that exosomes derived from HTLV-1-infected cells contain unique host and viral proteins that may contribute to HTLV-1-induced pathogenesis. We found exosomes derived from infected cells to contain Tax protein and proinflammatory mediators as well as viral mRNA transcripts, including Tax, HBZ, and Env. Furthermore, we observed that exosomes released from HTLV-1-infected Tax-expressing cells contributed to enhanced survival of exosome-recipient cells when treated with Fas antibody. This survival was cFLIP-dependent, with Tax showing induction of NF-κB in exosome-recipient cells. Finally, IL-2-dependent CTLL-2 cells that received Tax-containing exosomes were protected from apoptosis through activation of AKT. Similar experiments with primary cultures showed protection and survival of peripheral blood mononuclear cells even in the absence of phytohemagglutinin/IL-2. Surviving cells contained more phosphorylated Rb, consistent with the role of Tax in regulation of the cell cycle. Collectively, these results suggest that exosomes may play an important role in extracellular delivery of functional HTLV-1 proteins and mRNA to recipient cells. PMID:24939845

  8. Human T-lymphotropic virus type 1 infection and disease in Spain.

    Science.gov (United States)

    de Mendoza, Carmen; Caballero, Estrella; Aguilera, Antonio; Requena, Silvia; de Lejarazu, Raúl Ortiz; Pirón, María; González, Rocío; Jiménez, Ana; Roc, Lourdes; Treviño, Ana; Benito, Rafael; Fernández-Alonso, Miriam; Aguinaga, Aitziber; Rodríguez, Carmen; García-Costa, Juan; Blanco, Lidia; Ramos, José M; Calderón, Enrique; Eirós, José M; Sauleda, Silvia; Barreiro, Pablo; Soriano, Vicente

    2017-07-31

    : Human T-lymphotropic virus type 1 (HTLV-1) infection is a neglected disease despite roughly 15 million people are chronically infected worldwide. Lifelong less than 10% of carriers develop life-threatening diseases, mostly a subacute myelopathy known as tropical spastic paraparesis (TSP) and a lymphoproliferative disorder named adult T-cell leukemia (ATL). HTLV-1 is efficiently transmitted perinatally (breastfeeding), sexually (more from men to women) and parenterally (transfusions, injection drug user (IDU), and transplants). To date there is neither prophylactic vaccine nor effective antiviral therapy. A total of 327 cases of HTLV-1 infection had been reported at the HTLV-1 Spanish registry until December 2016, of whom 34 had been diagnosed with TSP and 25 with ATL. Overall 62% were Latin American immigrants and 13% were persons of African origin. The incidence of HTLV-1 in Spain has remained stable for nearly a decade with 20-25 new cases yearly. Of the 21 newly diagnosed HTLV-1 cases during year 2016, one was a native Spaniard pregnant woman, and four presented with symptomatic disease, including three with ATL and one with TSP. Underdiagnosis of HTLV-1 in Spain must be high (iceberg model), which may account for the disproportionate high rate of symptomatic cases (almost 20%) and the late recognition of preventable HTLV-1 transmissions in special populations, such as newborns and transplant recipients. Our current estimate is of 10 000 persons living with HTLV-1 infection in Spain. Given the large flux of immigrants and visitors from HTLV-1 endemic regions to Spain, the expansion of HTLV-1 screening policies is warranted. At this time, it seems worth recommending HTLV testing to all donor/recipient organ transplants and pregnant women regardless place of birth. Although current leukoreduction procedures largely prevent HTLV-1 transmission by blood transfusions, HTLV testing of all first-time donors should be cost-effective contributing to unveil

  9. Complex cell cycle abnormalities caused by human T-lymphotropic virus type 1 Tax.

    Science.gov (United States)

    Yang, Liangpeng; Kotomura, Naoe; Ho, Yik-Khuan; Zhi, Huijun; Bixler, Sandra; Schell, Michael J; Giam, Chou-Zen

    2011-03-01

    Human T-lymphotropic virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia/lymphoma (ATL), a malignancy of CD4(+) T cells whose etiology is thought to be associated with the viral trans-activator Tax. We have shown recently that Tax can drastically upregulate the expression of p27(Kip1) and p21(CIP1/WAF1) through protein stabilization and mRNA trans-activation and stabilization, respectively. The Tax-induced surge in p21(CIP1/WAF1) and p27(Kip1) begins in S phase and results in cellular senescence. Importantly, HeLa and SupT1 T cells infected by HTLV-1 also arrest in senescence, thus challenging the notion that HTLV-1 infection causes cell proliferation. Here we use time-lapse microscopy to investigate the effect of Tax on cell cycle progression in two reporter cell lines, HeLa/18x21-EGFP and HeLa-FUCCI, that express enhanced green fluorescent protein (EGFP) under the control of 18 copies of the Tax-responsive 21-bp repeat element and fluorescent ubiquitin cell cycle indicators, respectively. Tax-expressing HeLa cells exhibit elongated or stalled cell cycle phases. Many of them bypass mitosis and become single senescent cells as evidenced by the expression of senescence-associated β-galactosidase. Such cells have twice the normal equivalent of cellular contents and hence are enlarged, with exaggerated nuclei. Interestingly, nocodazole treatment revealed a small variant population of HeLa/18x21-EGFP cells that could progress into mitosis normally with high levels of Tax expression, suggesting that genetic or epigenetic changes that prevent Tax-induced senescence can occur spontaneously at a detectable frequency.

  10. Human T-lymphotropic virus type 1-infected cells secrete exosomes that contain Tax protein.

    Science.gov (United States)

    Jaworski, Elizabeth; Narayanan, Aarthi; Van Duyne, Rachel; Shabbeer-Meyering, Shabana; Iordanskiy, Sergey; Saifuddin, Mohammed; Das, Ravi; Afonso, Philippe V; Sampey, Gavin C; Chung, Myung; Popratiloff, Anastas; Shrestha, Bindesh; Sehgal, Mohit; Jain, Pooja; Vertes, Akos; Mahieux, Renaud; Kashanchi, Fatah

    2014-08-08

    Human T-lymphotropic virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia and HTLV-1-associated myelopathy/tropical spastic paraparesis. The HTLV-1 transactivator protein Tax controls many critical cellular pathways, including host cell DNA damage response mechanisms, cell cycle progression, and apoptosis. Extracellular vesicles called exosomes play critical roles during pathogenic viral infections as delivery vehicles for host and viral components, including proteins, mRNA, and microRNA. We hypothesized that exosomes derived from HTLV-1-infected cells contain unique host and viral proteins that may contribute to HTLV-1-induced pathogenesis. We found exosomes derived from infected cells to contain Tax protein and proinflammatory mediators as well as viral mRNA transcripts, including Tax, HBZ, and Env. Furthermore, we observed that exosomes released from HTLV-1-infected Tax-expressing cells contributed to enhanced survival of exosome-recipient cells when treated with Fas antibody. This survival was cFLIP-dependent, with Tax showing induction of NF-κB in exosome-recipient cells. Finally, IL-2-dependent CTLL-2 cells that received Tax-containing exosomes were protected from apoptosis through activation of AKT. Similar experiments with primary cultures showed protection and survival of peripheral blood mononuclear cells even in the absence of phytohemagglutinin/IL-2. Surviving cells contained more phosphorylated Rb, consistent with the role of Tax in regulation of the cell cycle. Collectively, these results suggest that exosomes may play an important role in extracellular delivery of functional HTLV-1 proteins and mRNA to recipient cells.

  11. Reexamination of human T cell lymphotropic virus (HTLV-I/II) prevalence

    Science.gov (United States)

    Zucker-Franklin, Dorothea; Pancake, Bette A.; Marmor, Michael; Legler, Patricia M.

    1997-01-01

    In the United States, blood donors are being screened for infection with human T cell lymphotropic viruses I and II (HTLV-I/II) by serologic means, which detect antibodies to the structural proteins of these viruses. Because patients with mycosis fungoides (MF) usually do not have such antibodies even though their cells harbor HTLV-I Tax and/or pol proviral sequences, it was questioned whether the prevalence of HTLV infection among healthy blood donors may also be underestimated by current means of testing. To examine this possibility, a study on specimens of relatives of mycosis fungoides patients (MFR) was begun. In addition, to collect data more expeditiously, a cohort of former injection drug users (IDUs) was tested by routine serologic methods, as well as by PCR/Southern blot analysis for Tax, pol, and gag proviral sequences and Western blot analysis for antibodies to the Tax gene product. To date, 6/8 MFRs and 42/81 (51.8%) of HIV-negative IDUs proved to be positive for HTLV, whereas routine serology identified none of the MFR and only 18/81 (22.2%) of the IDUs. Among the latter test subjects, the incidence of HTLV-I also proved to be 10 times higher than expected. Therefore, it is likely that among healthy blood donors infection with HTLV-I/II is more prevalent than is currently assumed. Since Tax is the transforming sequence of HTLV-I/II, testing for Tax sequences and antibodies to its gene product may be desirable in blood transfusion and tissue donor facilities. PMID:9177230

  12. Reexamination of human T cell lymphotropic virus (HTLV-I/II) prevalence.

    Science.gov (United States)

    Zucker-Franklin, D; Pancake, B A; Marmor, M; Legler, P M

    1997-06-10

    In the United States, blood donors are being screened for infection with human T cell lymphotropic viruses I and II (HTLV-I/II) by serologic means, which detect antibodies to the structural proteins of these viruses. Because patients with mycosis fungoides (MF) usually do not have such antibodies even though their cells harbor HTLV-I Tax and/or pol proviral sequences, it was questioned whether the prevalence of HTLV infection among healthy blood donors may also be underestimated by current means of testing. To examine this possibility, a study on specimens of relatives of mycosis fungoides patients (MFR) was begun. In addition, to collect data more expeditiously, a cohort of former injection drug users (IDUs) was tested by routine serologic methods, as well as by PCR/Southern blot analysis for Tax, pol, and gag proviral sequences and Western blot analysis for antibodies to the Tax gene product. To date, 6/8 MFRs and 42/81 (51.8%) of HIV-negative IDUs proved to be positive for HTLV, whereas routine serology identified none of the MFR and only 18/81 (22.2%) of the IDUs. Among the latter test subjects, the incidence of HTLV-I also proved to be 10 times higher than expected. Therefore, it is likely that among healthy blood donors infection with HTLV-I/II is more prevalent than is currently assumed. Since Tax is the transforming sequence of HTLV-I/II, testing for Tax sequences and antibodies to its gene product may be desirable in blood transfusion and tissue donor facilities.

  13. Regulation of human T-lymphotropic virus type I latency and reactivation by HBZ and Rex.

    Directory of Open Access Journals (Sweden)

    Subha Philip

    2014-04-01

    Full Text Available Human T lymphotropic virus type I (HTLV-I infection is largely latent in infected persons. How HTLV-1 establishes latency and reactivates is unclear. Here we show that most HTLV-1-infected HeLa cells become senescent. By contrast, when NF-κB activity is blocked, senescence is averted, and infected cells continue to divide and chronically produce viral proteins. A small population of infected NF-κB-normal HeLa cells expresses low but detectable levels of Tax and Rex, albeit not Gag or Env. In these "latently" infected cells, HTLV-1 LTR trans-activation by Tax persists, but NF-κB trans-activation is attenuated due to inhibition by HBZ, the HTLV-1 antisense protein. Furthermore, Gag-Pol mRNA localizes primarily in the nuclei of these cells. Importantly, HBZ was found to inhibit Rex-mediated export of intron-containing mRNAs. Over-expression of Rex or shRNA-mediated silencing of HBZ led to viral reactivation. Importantly, strong NF-κB inhibition also reactivates HTLV-1. Hence, during HTLV-1 infection, when Tax/Rex expression is robust and dominant over HBZ, productive infection ensues with expression of structural proteins and NF-κB hyper-activation, which induces senescence. When Tax/Rex expression is muted and HBZ is dominant, latent infection is established with expression of regulatory (Tax/Rex/HBZ but not structural proteins. HBZ maintains viral latency by down-regulating Tax-induced NF-κB activation and senescence, and by inhibiting Rex-mediated expression of viral structural proteins.

  14. Discovery of a new human T-cell lymphotropic virus (HTLV-3 in Central Africa

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    Mahieux Renaud

    2005-05-01

    Full Text Available Abstract Human T-cell Leukemia virus type 1 (HTLV-1 and type 2 (HTLV-2 are pathogenic retroviruses that infect humans and cause severe hematological and neurological diseases. Both viruses have simian counterparts (STLV-1 and STLV-2. STLV-3 belongs to a third group of lymphotropic viruses which infect numerous African monkeys species. Among 240 Cameroonian plasma tested for the presence of HTLV-1 and/or HTLV-2 antibodies, 48 scored positive by immunofluorescence. Among those, 27 had indeterminate western-blot pattern. PCR amplification of pol and tax regions, using HTLV-1, -2 and STLV-3 highly conserved primers, demonstrated the presence of a new human retrovirus in one DNA sample. tax (180 bp and pol (318 bp phylogenetic analyses demonstrated the strong relationships between the novel human strain (Pyl43 and STLV-3 isolates from Cameroon. The virus, that we tentatively named HTLV-3, originated from a 62 years old Bakola Pygmy living in a remote settlement in the rain forest of Southern Cameroon. The plasma was reactive on MT2 cells but was negative on C19 cells. The HTLV 2.4 western-blot exhibited a strong reactivity to p19 and a faint one to MTA-1. On the INNO-LIA strip, it reacted faintly with the generic p19 (I/II, but strongly to the generic gp46 (I/II and to the specific HTLV-2 gp46. The molecular relationships between Pyl43 and STLV-3 are thus not paralleled by the serological results, as most of the STLV-3 infected monkeys have an "HTLV-2 like" WB pattern. In the context of the multiple interspecies transmissions which occurred in the past, and led to the present-day distribution of the PTLV-1, it is thus very tempting to speculate that this newly discovered human retrovirus HTLV-3 might be widespread, at least in the African continent.

  15. Expression of the small T antigen of Lymphotropic Papovavirus is sufficient to transform primary mouse embryo fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Tushar; Robles, Maria Teresa Sáenz [Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260 (United States); Schowalter, Rachel M.; Buck, Christopher B. [Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892-4263 (United States); Pipas, James M., E-mail: pipas@pitt.edu [Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260 (United States)

    2016-01-15

    Polyomaviruses induce cell proliferation and transformation through different oncoproteins encoded within the early region (ER): large T antigen (LT), small T antigen (sT) and, in some cases, additional components. Each virus utilizes different mechanisms to achieve transformation. For instance, the LTs of Simian virus 40 (SV40), BK and/or JC virus can induce transformation; but Merkel Cell Polyomavirus (MCPyV) requires expression of sT. Lymphotropic Papovavirus (LPV) is closely related to Human Polyomavirus 9 (HuPyV9) and, under similar conditions, mice expressing LPV.ER exhibit higher rates of tumor formation than mice expressing SV40.ER. We have investigated the contributions of individual LPV.ER components to cell transformation. In contrast to SV40, LPV.ER transforms mouse embryonic fibroblasts (MEFs), but expression of LPV LT is insufficient to transform MEFs. Furthermore, LPV sT induces immortalization and transformation of MEFs. Thus, in the case of LPV, sT is the main mediator of oncogenesis. - Highlights: • Characterization of early region products from the Lymphotropic Polyomavirus (LPV). • On its own, sT immortalizes and transforms mouse primary cells, and is able to block p53 activation. • Combined LT and sT expression induces a greater rate of proliferation than either LT or sT alone.

  16. MAGNET

    CERN Multimedia

    by B. Curé

    2011-01-01

    The magnet operation was very satisfactory till the technical stop at the end of the year 2010. The field was ramped down on 5th December 2010, following the successful regeneration test of the turbine filters at full field on 3rd December 2010. This will limit in the future the quantity of magnet cycles, as it is no longer necessary to ramp down the magnet for this type of intervention. This is made possible by the use of the spare liquid Helium volume to cool the magnet while turbines 1 and 2 are stopped, leaving only the third turbine in operation. This obviously requires full availability of the operators to supervise the operation, as it is not automated. The cryogenics was stopped on 6th December 2010 and the magnet was left without cooling until 18th January 2011, when the cryoplant operation resumed. The magnet temperature reached 93 K. The maintenance of the vacuum pumping was done immediately after the magnet stop, when the magnet was still at very low temperature. Only the vacuum pumping of the ma...

  17. Exploring type II microcalcifications in benign and premalignant breast lesions by shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS)

    Science.gov (United States)

    Liang, Lijia; Zheng, Chao; Zhang, Haipeng; Xu, Shuping; Zhang, Zhe; Hu, Chengxu; Bi, Lirong; Fan, Zhimin; Han, Bing; Xu, Weiqing

    2014-11-01

    The characteristics of type II microcalcifications in fibroadenoma (FB), atypical ductal hyperplasia (ADH), and ductal carcinoma in situ (DCIS) breast tissues has been analyzed by the fingerprint features of Raman spectroscopy. Fresh breast tissues were first handled to frozen sections and then they were measured by normal Raman spectroscopy. Due to inherently low sensitivity of Raman scattering, Au@SiO2 shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) technique was utilized. A total number of 71 Raman spectra and 70 SHINERS spectra were obtained from the microcalcifications in benign and premalignant breast tissues. Principal component analysis (PCA) was used to distinguish the type II microcalcifications between these tissues. This is the first time to detect type II microcalcifications in premalignant (ADH and DCIS) breast tissue frozen sections, and also the first time SHINERS has been utilized for breast cancer detection. Conclusions demonstrated in this paper confirm that SHINERS has great potentials to be applied to the identification of breast lesions as an auxiliary method to mammography in the early diagnosis of breast cancer.

  18. Gold nanoparticles enhance methylene blue-induced photodynamic therapy: a novel therapeutic approach to inhibit Candida albicans biofilm.

    Science.gov (United States)

    Khan, Shakir; Alam, Fahad; Azam, Ameer; Khan, Asad U

    2012-01-01

    This article explores the novel gold nanoparticle-enhanced photodynamic therapy of methylene blue against recalcitrant pathogenic Candida albicans biofilm. Physiochemical (X-ray diffraction, ultraviolet-visible absorption, photon cross-correlation, FTIR, and fluorescence spectroscopy) and electron microscopy techniques were used to characterize gold nanoparticles as well as gold nanoparticle-methylene blue conjugate. A 38.2-J/cm(2) energy density of 660-nm diode laser was applied for activation of gold nanoparticle-methylene blue conjugate and methylene blue against C. albicans biofilm and cells. Antibiofilm assays, confocal laser scanning, and electron microscopy were used to investigate the effects of the conjugate. Physical characteristics of the gold nanoparticles (21 ± 2.5 nm and 0.2 mg/mL) and methylene blue (20 μg/mL) conjugation were confirmed by physicochemical and electron microscopy techniques. Antibiofilm assays and microscopic studies showed significant reduction of biofilm and adverse effect against Candida cells in the presence of conjugate. Fluorescence spectroscopic study confirmed type I photo toxicity against biofilm. Gold nanoparticle conjugate-mediated photodynamic therapy may be used against nosocomially acquired refractory Candida albicans biofilm.

  19. Novel strontium-doped bioactive glass nanoparticles enhance proliferation and osteogenic differentiation of human bone marrow stromal cells

    Energy Technology Data Exchange (ETDEWEB)

    Strobel, L. A. [University of Erlangen-Nuremberg Medical Center, Department of Plastic and Hand Surgery (Germany); Hild, N.; Mohn, D.; Stark, W. J. [ETH Zurich, Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering (Switzerland); Hoppe, A. [University of Erlangen-Nuremberg, Department of Materials Science and Engineering, Institute of Biomaterials (Germany); Gbureck, U. [University of Wuerzburg, Department for Functional Materials in Medicine and Dentistry (Germany); Horch, R. E.; Kneser, U. [University of Erlangen-Nuremberg Medical Center, Department of Plastic and Hand Surgery (Germany); Boccaccini, A. R., E-mail: aldo.boccaccini@ww.uni-erlangen.de [University of Erlangen-Nuremberg, Department of Materials Science and Engineering, Institute of Biomaterials (Germany)

    2013-07-15

    The present study investigates a new family of bioactive glass nanoparticles with and without Sr-doping focusing on the influence of the nanoparticles on human bone marrow stromal cells (hBMSCs) in vitro. The bioactive glass nanoparticles were fabricated by flame spray synthesis and a particle diameter of 30-35 nm was achieved. Glass nanoparticles were undoped (BG 13-93-0Sr) or doped with 5 wt% strontium (Sr) (BG 13-93-5Sr) and used at concentrations of 10 and 100 {mu}g/cm Superscript-Two (particles per culture plate area), respectively. Cells were cultured for 14 days after which the samples were analysed regarding metabolic activity and expression of various bone-specific genes. Cell growth and morphology indicated the high cytocompatibility of the nanoparticulate bioactive glass. The presence of the nanoparticles enhanced cell growth compared to the plain polystyrene control group. At a concentration of 100 {mu}g/cm Superscript-Two , Sr-doped particles led to significantly enhanced gene expression of osteocalcin, collagen type 1 and vascular endothelial growth factor. Thus, Sr-doped nanoparticles showing a dose-dependent increase of osteogenic differentiation in hBMSCs are a promising biomaterial for bone regeneration purposes.

  20. Mass Spectrometry Imaging of low Molecular Weight Compounds in Garlic (Allium sativum L.) with Gold Nanoparticle Enhanced Target.

    Science.gov (United States)

    Misiorek, Maria; Sekuła, Justyna; Ruman, Tomasz

    2017-06-13

    Garlic (Allium sativum) is the subject of many studies due to its numerous beneficial properties. Although compounds of garlic have been studied by various analytical methods, their tissue distributions are still unclear. Mass spectrometry imaging (MSI) appears to be a very powerful tool for the identification of the localisation of compounds within a garlic clove. Visualisation of the spatial distribution of garlic low-molecular weight compounds with nanoparticle-based MSI. Compounds occurring on the cross-section of sprouted garlic has been transferred to gold-nanoparticle enhanced target (AuNPET) by imprinting. The imprint was then subjected to MSI analysis. The results suggest that low molecular weight compounds, such as amino acids, dipeptides, fatty acids, organosulphur and organoselenium compounds are distributed within the garlic clove in a characteristic manner. It can be connected with their biological functions and metabolic properties in the plant. New methodology for the visualisation of low molecular weight compounds allowed a correlation to be made between their spatial distribution within a sprouted garlic clove and their biological function. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  1. Nanoparticle Enhanced MRI Scanning to Detect Cellular Inflammation in Experimental Chronic Renal Allograft Rejection

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    S. R. Alam

    2015-01-01

    Full Text Available Objectives. We investigated whether ultrasmall paramagnetic particles of iron oxide- (USPIO- enhanced magnetic resonance imaging (MRI can detect experimental chronic allograft damage in a murine renal allograft model. Materials and Methods. Two cohorts of mice underwent renal transplantation with either a syngeneic isograft or allograft kidney. MRI scanning was performed prior to and 48 hours after USPIO infusion using T2∗-weighted protocols. R2∗ values were calculated to indicate the degree of USPIO uptake. Native kidneys and skeletal muscle were imaged as reference tissues and renal explants analysed by histology and electron microscopy. Results. R2∗ values in the allograft group were higher compared to the isograft group when indexed to native kidney (median 1.24 (interquartile range: 1.12 to 1.36 versus 0.96 (0.92 to 1.04, P<0.01. R2∗ values were also higher in the allograft transplant when indexed to skeletal muscle (6.24 (5.63 to 13.51 compared to native kidney (2.91 (1.11 to 6.46 P<0.05. Increased R2∗ signal in kidney allograft was associated with macrophage and iron staining on histology. USPIO were identified within tissue resident macrophages on electron microscopy. Conclusion. USPIO-enhanced MRI identifies macrophage.

  2. Irradiation performance of rare earth and nanoparticle enhanced high temperature superconducting films based on YBCO

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    K.J. Leonard

    2016-12-01

    Full Text Available The new series of commercially produced high temperature superconducting (HTS tapes based on the YBa2Cu3O7 (YBCO structure have attracted renewed attention for their performance under applied magnetic fields without significant loss in supercurrent compared to the earlier generation of conductors. This adaptability is achieved through rare earth substitution and dopants resulting in the formation of nanoparticles and extended defects within the superconducting film matrix. The electrical performance of Zr-(Gdx,Y1−xBa2Cu3O7 and (Y1−x,DyxBa2Cu3O7 coated conductor tapes were tested prior to and after neutron exposures between 6.54×1017 and 7.00×1018 n/cm2 (E > 0.1MeV. Results showed a decrease in superconducting current with neutron irradiation for the range of fluences tested, with losses in the Zr-(Gdx,Y1−xBa2Cu3O7 conductor being more rapid. Post-irradiation testing was limited to evaluation at 77K and applied fields of up to 0.5Tesla, and therefore testing at lower temperatures and higher applied fields may result in improved superconducting properties as shown in previous ion irradiation work. Under the conditions tested, the doped conductors showed a loss in critical current at fluences lower than that of undoped YBa2Cu3O7 tapes reported on in literature.

  3. Strongyloidiasis and infective dermatitis alter human T lymphotropic virus-1 clonality in vivo.

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    Nicolas A Gillet

    Full Text Available Human T-lymphotropic Virus-1 (HTLV-1 is a retrovirus that persists lifelong by driving clonal proliferation of infected T-cells. HTLV-1 causes a neuroinflammatory disease and adult T-cell leukemia/lymphoma. Strongyloidiasis, a gastrointestinal infection by the helminth Strongyloides stercoralis, and Infective Dermatitis associated with HTLV-1 (IDH, appear to be risk factors for the development of HTLV-1 related diseases. We used high-throughput sequencing to map and quantify the insertion sites of the provirus in order to monitor the clonality of the HTLV-1-infected T-cell population (i.e. the number of distinct clones and abundance of each clone. A newly developed biodiversity estimator called "DivE" was used to estimate the total number of clones in the blood. We found that the major determinant of proviral load in all subjects without leukemia/lymphoma was the total number of HTLV-1-infected clones. Nevertheless, the significantly higher proviral load in patients with strongyloidiasis or IDH was due to an increase in the mean clone abundance, not to an increase in the number of infected clones. These patients appear to be less capable of restricting clone abundance than those with HTLV-1 alone. In patients co-infected with Strongyloides there was an increased degree of oligoclonal expansion and a higher rate of turnover (i.e. appearance and disappearance of HTLV-1-infected clones. In Strongyloides co-infected patients and those with IDH, proliferation of the most abundant HTLV-1⁺ T-cell clones is independent of the genomic environment of the provirus, in sharp contrast to patients with HTLV-1 infection alone. This implies that new selection forces are driving oligoclonal proliferation in Strongyloides co-infection and IDH. We conclude that strongyloidiasis and IDH increase the risk of development of HTLV-1-associated diseases by increasing the rate of infection of new clones and the abundance of existing HTLV-1⁺ clones.

  4. Family Aggregation of Human T-Lymphotropic Virus 1-Associated Diseases: A Systematic Review

    Science.gov (United States)

    Alvarez, Carolina; Gotuzzo, Eduardo; Vandamme, Anne-Mieke; Verdonck, Kristien

    2016-01-01

    Human T-lymphotropic virus 1 (HTLV-1) is a retrovirus that produces a persistent infection. Two transmission routes (from mother to child and via sexual intercourse) favor familial clustering of HTLV-1. It is yet unknown why most HTLV-1 carriers remain asymptomatic while about 10% of them develop complications. HTLV-1 associated diseases were originally described as sporadic entities, but familial presentations have been reported. To explore what is known about family aggregation of HTLV-1-associated diseases we undertook a systematic review. We aimed at answering whether, when, and where family aggregation of HTLV-1-associated diseases was reported, which relatives were affected and which hypotheses were proposed to explain aggregation. We searched MEDLINE, abstract books of HTLV conferences and reference lists of selected papers. Search terms used referred to HTLV-1 infection, and HTLV-1-associated diseases, and family studies. HTLV-1-associated diseases considered are adult T-cell leukemia/lymphoma (ATLL), HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), HTLV-1-associated uveitis, and infective dermatitis. Seventy-four records reported HTLV-1-associated diseases in more than one member of the same family and were included. Most reports came from HTLV-1-endemic countries, mainly Japan (n = 30) and Brazil (n = 10). These reports described a total of 270 families in which more than one relative had HTLV-1-associated diseases. In most families, different family members suffered from the same disease (n = 223). The diseases most frequently reported were ATLL (115 families) and HAM/TSP (102 families). Most families (n = 144) included two to four affected individuals. The proportion of ATLL patients with family history of ATLL ranged from 2 to 26%. The proportion of HAM/TSP patients with family history of HAM/TSP ranged from 1 to 48%. The predominant cluster types for ATLL were clusters of siblings and parent-child pairs and for HAM/TSP, an affected

  5. High prevalence of human T-lymphotropic virus infection in indigenous women from the peruvian Amazon.

    Directory of Open Access Journals (Sweden)

    Magaly M Blas

    Full Text Available BACKGROUND: In an earlier study, we detected an association between human T-cell lymphotropic virus (HTLV infection and cervical human papillomavirus (HPV in indigenous Amazonian Peruvian women of the Shipibo-Konibo ethnic group. As both HTLV and HPV can be transmitted sexually, we now report a population-based study examining the prevalence and risk factors for HTLV-1 and HTLV-2 infection in this population. METHODS: Between July and December 2010, we conducted a comprehensive screening for HTLV among Shipibo-Konibo women 15 to 39 years of age living in two communities located in Lima and in 17 communities located within four hours by car or boat from the Amazonian city of Pucallpa in Peru. RESULTS: We screened 1,253 Shipibo-Konibo women for HTLV infection 74 (5.9% tested positive for HTLV-1, 47 (3.8% for HTLV-2 infection, and 4 (0.3% had indeterminate results. In the multivariate analysis, factors associated with HTLV-1 infection included: older age (Prevalence Ratio (PR: 1.04, 95% CI 1.00-1.08, primary education or less (PR: 2.01, 95% CI: 1.25-3.24, younger or same age most recent sex partner (PR: 1.66, 95% CI: 1.00-2.74, and having a most recent sex partner who worked at a logging camp (PR: 1.73, 95% CI: 1.09-2.75. The only factor associated with HTLV-2 infection was older age (PR: 1.08, 95% CI: 1.03-1.12. CONCLUSION: HTLV infection is endemic among Shipibo-Konibo women. Two characteristics of the sexual partner (younger age and labor history were associated with infection in women. These results suggest the need for implementation of both HTLV screening during the antenatal healthcare visits of Shipibo-Konibo women, and counseling about the risk of HTLV transmission through prolonged breastfeeding in infected women. We also recommend the implementation of prevention programs to reduce sexual transmission of these viruses.

  6. MAGNET

    CERN Multimedia

    B. Curé

    2012-01-01

      The magnet was energised at the beginning of March 2012 at a low current to check all the MSS safety chains. Then the magnet was ramped up to 3.8 T on 6 March 2012. Unfortunately two days later an unintentional switch OFF of the power converter caused a slow dump. This was due to a misunderstanding of the CCC (CERN Control Centre) concerning the procedure to apply for the CMS converter control according to the beam-mode status at that time. Following this event, the third one since 2009, a discussion was initiated to define possible improvement, not only on software and procedures in the CCC, but also to evaluate the possibility to upgrade the CMS hardware to prevent such discharge from occurring because of incorrect procedure implementations. The magnet operation itself was smooth, and no power cuts took place. As a result, the number of magnetic cycles was reduced to the minimum, with only two full magnetic cycles from 0 T to 3.8 T. Nevertheless the magnet suffered four stops of the cryogeni...

  7. MAGNET

    CERN Multimedia

    Benoit Curé

    2010-01-01

    Operation of the magnet has gone quite smoothly during the first half of this year. The magnet has been at 4.5K for the full period since January. There was an unplanned short stop due to the CERN-wide power outage on May 28th, which caused a slow dump of the magnet. Since this occurred just before a planned technical stop of the LHC, during which access in the experimental cavern was authorized, it was decided to leave the magnet OFF until 2nd June, when magnet was ramped up again to 3.8T. The magnet system experienced a fault also resulting in a slow dump on April 14th. This was triggered by a thermostat on a filter choke in the 20kA DC power converter. The threshold of this thermostat is 65°C. However, no variation in the water-cooling flow rate or temperature was observed. Vibration may have been the root cause of the fault. All the thermostats have been checked, together with the cables, connectors and the read out card. The tightening of the inductance fixations has also been checked. More tem...

  8. MAGNET

    CERN Multimedia

    B. Curé

    2012-01-01

      Following the unexpected magnet stops last August due to sequences of unfortunate events on the services and cryogenics [see CMS internal report], a few more events and initiatives again disrupted the magnet operation. All the magnet parameters stayed at their nominal values during this period without any fault or alarm on the magnet control and safety systems. The magnet was stopped for the September technical stop to allow interventions in the experimental cavern on the detector services. On 1 October, to prepare the transfer of the liquid nitrogen tank on its new location, several control cables had to be removed. One cable was cut mistakenly, causing a digital input card to switch off, resulting in a cold-box (CB) stop. This tank is used for the pre-cooling of the magnet from room temperature down to 80 K, and for this reason it is controlled through the cryogenics control system. Since the connection of the CB was only allowed for a field below 2 T to avoid the risk of triggering a fast d...

  9. MAGNET

    CERN Multimedia

    B. Curé

    2012-01-01

      The magnet and its sub-systems were stopped at the beginning of the winter shutdown on 8th December 2011. The magnet was left without cooling during the cryogenics maintenance until 17th January 2012, when the cryoplant operation resumed. The magnet temperature reached 93 K. The vacuum pumping was maintained during this period. During this shutdown, the yearly maintenance was performed on the cryogenics, the vacuum pumps, the magnet control and safety systems, and the power converter and discharge lines. Several preventive actions led to the replacement of the electrovalve command coils, and the 20A DC power supplies of the magnet control system. The filters were cleaned on the demineralised water circuits. The oil of the diffusion pumps was changed. On the cryogenics, warm nitrogen at 343 K was circulated in the cold box to regenerate the filters and the heat exchangers. The coalescing filters have been replaced at the inlet of both the turbines and the lubricant trapping unit. The active cha...

  10. MAGNET

    CERN Multimedia

    Benoit Curé

    2010-01-01

    The magnet was successfully operated at the end of the year 2009 despite some technical problems on the cryogenics. The magnet was ramped up to 3.8 T at the end of November until December 16th when the shutdown started. The magnet operation met a few unexpected stops. The field was reduced to 3.5 T for about 5 hours on December 3rd due to a faulty pressure sensor on the helium compressor. The following day the CERN CCC stopped unintentionally the power converters of the LHC and the experiments, triggering a ramp down that was stopped at 2.7 T. The magnet was back at 3.8 T about 6 hours after CCC sent the CERN-wide command. Three days later, a slow dump was triggered due to a stop of the pump feeding the power converter water-cooling circuit, during an intervention on the water-cooling plant done after several disturbances on the electrical distribution network. The magnet was back at 3.8 T in the evening the same day. On December 10th a break occurred in one turbine of the cold box producing the liquid ...

  11. MAGNET

    CERN Multimedia

    B. Curé

    2013-01-01

      The magnet was operated without any problem until the end of the LHC run in February 2013, apart from a CERN-wide power glitch on 10 January 2013 that affected the CMS refrigerator, causing a ramp down to 2 T in order to reconnect the coldbox. Another CERN-wide power glitch on 15 January 2013 didn’t affect the magnet subsystems, the cryoplant or the power converter. At the end of the magnet run, the reconnection of the coldbox at 2.5 T was tested. The process will be updated, in particular the parameters of some PID valve controllers. The helium flow of the current leads was reduced but only for a few seconds. The exercise will be repeated with the revised parameters to validate the automatic reconnection process of the coldbox. During LS1, the water-cooling services will be reduced and many interventions are planned on the electrical services. Therefore, the magnet cryogenics and subsystems will be stopped for several months, and the magnet cannot be kept cold. In order to avoid unc...

  12. MAGNET

    CERN Multimedia

    B. Curé

    2011-01-01

    The CMS magnet has been running steadily and smoothly since the summer, with no detected flaw. The magnet instrumentation is entirely operational and all the parameters are at their nominal values. Three power cuts on the electrical network affected the magnet run in the past five months, with no impact on the data-taking as the accelerator was also affected at the same time. On 22nd June, a thunderstorm caused a power glitch on the service electrical network. The primary water cooling at Point 5 was stopped. Despite a quick restart of the water cooling, the inlet temperature of the demineralised water on the busbar cooling circuit increased by 5 °C, up to 23.3 °C. It was kept below the threshold of 27 °C by switching off other cooling circuits to avoid the trigger of a slow dump of the magnet. The cold box of the cryogenics also stopped. Part of the spare liquid helium volume was used to maintain the cooling of the magnet at 4.5 K. The operators of the cryogenics quickly restarted ...

  13. Pursuing shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) for concomitant detection of breast lesions and microcalcifications

    Science.gov (United States)

    Zheng, Chao; Shao, Wanting; Paidi, Santosh Kumar; Han, Bing; Fu, Tong; Wu, Di; Bi, Lirong; Xu, Weiqing; Fan, Zhimin; Barman, Ishan

    2015-10-01

    Although tissue staining followed by morphologic identification remains the gold standard for diagnosis of most cancers, such determinations relying solely on morphology are often hampered by inter- and intra-observer variability. Vibrational spectroscopic techniques, in contrast, offer objective markers for diagnoses and can afford disease detection prior to alterations in cellular and extracellular architecture by furnishing a rapid ``omics''-like view of the biochemical status of the probed specimen. Here, we report a classification approach to concomitantly detect microcalcification status and local pathological state in breast tissue, featuring a combination of vibrational spectroscopy that focuses on the tumor and its microenvironment, and multivariate data analysis of spectral markers reflecting molecular expression. We employ the unprecedented sensitivity and exquisite molecular specificity offered by Au@SiO2 shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) to probe the presence of calcified deposits and distinguish between normal breast tissues, fibroadenoma, atypical ductal hyperplasia, ductal carcinoma in situ (DCIS), and invasive ductal carcinoma (IDC). By correlating the spectra with the corresponding histologic assessment, we developed partial least squares-discriminant analysis derived decision algorithm that provides excellent diagnostic power in the fresh frozen sections (overall accuracy of 99.4% and 93.6% using SHINs for breast lesions with and without microcalcifications, respectively). The performance of this decision algorithm is competitive with or supersedes that of analogous algorithms employing spontaneous Raman spectroscopy while enabling facile detection due to the considerably higher intensity of SHINERS. Our results pave the way for rapid tissue spectral pathology measurements using SHINERS that can offer a novel stain-free route to accurate and economical diagnoses without human interpretation.Although tissue staining

  14. MAGNETS

    Science.gov (United States)

    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.

  15. Are lipid disorders involved in the predominance of human T-lymphotropic virus-1 infections in women?

    Directory of Open Access Journals (Sweden)

    Luciana Debortoli de Carvalho

    2015-12-01

    Full Text Available Abstract INTRODUCTION : The human T-lymphotropic virus-1 (HTLV-1 is associated with chronic inflammatory diseases such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP, a chronic inflammatory disease. Disturbances in lipid metabolism are involved in inflammatory and demyelinating diseases. METHODS : Plasma levels of triglycerides, total cholesterol, and fractions of HTLV-1-infected individuals of both sexes with different clinical progressions were determined. RESULTS : Elevated levels of triglyceride and very low-density lipoproteins (VLDL were exclusively detected in HTLV-1-infected women from asymptomatic and HAM/TSP groups compared with uninfected individuals (p = 0.02. CONCLUSIONS : Elevated triglyceride and VLDL levels in HTLV-1-infected women may be related to the predominance of HAM/TSP in women.

  16. Human T-cell lymphotropic virus type III infection in a cohort of homosexual men in New York City

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, C.E.; Taylor, P.E.; Zang, E.A.; Morrison, J.M.; Harley, E.J.; de Cordoba, S.R.; Bacino, C.; Ting, R.C.; Bodner, A.J.; Sarngadharan, M.G.; Gallo, R.C.

    1986-04-25

    Using blood samples collected since 1978, the authors investigated the epidemiology of human T-cell lymphotropic virus type III (HTLV-III), the etiologic agent of the acquired immunodeficiency syndrome, in a group of 378 homosexually active men who have resided in New York City since the acquire immunodeficiency syndrome epidemic began. The anti-HTLV-III prevalence was 6.6% in sera from 1978 or 1979, and the subsequent annual incidence of seroconversion among susceptible men ranged between 5.5% and 10.6%. The highest incidences were in recent years, even though these men reported a decrease in their sexual activity during this time. These data demonstrate the continuing risk of HTLV-III infections in the homosexual population studied and emphasize the need for more effective prevention of transmission. The year during which antibody was first present was the only factor identified that was associated with altered cell-mediated immunity in antibody-positive men.

  17. Regional Lymphotropic Therapy in Combination with Low Level Laser Therapy for Treating Multi-Drug-Resistant Tuberculosis

    Directory of Open Access Journals (Sweden)

    Oksana Dogorova

    2016-03-01

    Full Text Available With the growing incidence of Multi-Drug-Resistant Tuberculosis (MDR-TB in newly identified patients, novel multimodality treatment methods are needed, aimed at reducing the time to sputum conversion and cavity healing, which would be applicable in MDR cases. Our experimental treatment consisted of the following: 1 chemotherapy based on the drug sensitivity profile, 2 local laser irradiation therapy for 25 days, and lymphotropic administration of isoniazid (to subcutaneous tissue in alternating locations: underarm area; fifth intercostal space along the sterna border; subclavian area where the first rib meets the sternum in a daily dose of 10mg/kg 5 times a week. This treatment was significantly more effective in newly detected destructive MDR-TB versus the standard Category IV regimen for MDR-TB in terms of reduced time for sputum culture conversion and cavity healing, estimated to be 6 months after initiation of treatment.

  18. MAGNET

    CERN Multimedia

    B. Curé

    2011-01-01

    The magnet ran smoothly in the last few months until a fast dump occurred on 9th May 2011. Fortunately, this occurred in the afternoon of the first day of the technical stop. The fast dump was due to a valve position controller that caused the sudden closure of a valve. This valve is used to regulate the helium flow on one of the two current leads, which electrically connects the coil at 4.5 K to the busbars at room temperature. With no helium flow on the lead, the voltage drop and the temperatures across the leads increase up to the defined thresholds, triggering a fast dump through the Magnet Safety System (MSS). The automatic reaction triggered by the MSS worked properly. The helium release was limited as the pressure rise was just at the limit of the safety valve opening pressure. The average temperature of the magnet reached 72 K. It took four days to recover the temperature and refill the helium volumes. The faulty valve controller was replaced by a spare one before the magnet ramp-up resumed....

  19. MAGNET

    CERN Multimedia

    B. Curé

    2013-01-01

    The magnet is fully stopped and at room temperature. The maintenance works and consolidation activities on the magnet sub-systems are progressing. To consolidate the cryogenic installation, two redundant helium compressors will be installed as ‘hot spares’, to avoid the risk of a magnet downtime in case of a major failure of a compressor unit during operation. The screw compressors, their motors, the mechanical couplings and the concrete blocks are already available and stored at P5. The metallic structure used to access the existing compressors in SH5 will be modified to allow the installation of the two redundant ones. The plan is to finish the installation and commissioning of the hot spare compressors before the summer 2014. In the meantime, a bypass on the high-pressure helium piping will be installed for the connection of a helium drier unit later during the Long Shutdown 1, keeping this installation out of the schedule critical path. A proposal is now being prepared for the con...

  20. MAGNET

    CERN Multimedia

    B. Curé

    MAGNET During the winter shutdown, the magnet subsystems went through a full maintenance. The magnet was successfully warmed up to room temperature beginning of December 2008. The vacuum was broken later on by injecting nitrogen at a pressure just above one atmosphere inside the vacuum tank. This was necessary both to prevent any accidental humidity ingress, and to allow for a modification of the vacuum gauges on the vacuum tank and maintenance of the diffusion pumps. The vacuum gauges had to be changed, because of erratic variations on the measurements, causing spurious alarms. The new type of vacuum gauges has been used in similar conditions on the other LHC experiments and without problems. They are shielded against the stray field. The lubricants of the primary and diffusion pumps have been changed. Several minor modifications were also carried out on the equipment in the service cavern, with the aim to ease the maintenance and to allow possible intervention during operation. Spare sensors have been bough...

  1. MAGNET

    CERN Multimedia

    Benoit Curé

    2010-01-01

    The magnet worked very well at 3.8 T as expected, despite a technical issue that manifested twice in the cryogenics since June. All the other magnet sub-systems worked without flaw. The issue in the cryogenics was with the cold box: it could be observed that the cold box was getting progressively blocked, due to some residual humidity and air accumulating in the first thermal exchanger and in the adsorber at 65 K. This was later confirmed by the analysis during the regeneration phases. An increase in the temperature difference between the helium inlet and outlet across the heat exchanger and a pressure drop increase on the filter of the adsorber were observed. The consequence was a reduction of the helium flow, first compensated by the automatic opening of the regulation valves. But once they were fully opened, the flow and refrigeration power reduced as a consequence. In such a situation, the liquid helium level in the helium Dewar decreased, eventually causing a ramp down of the magnet current and a field...

  2. MAGNET

    CERN Multimedia

    Benoit Curé.

    The magnet operation restarted end of June this year. Quick routine checks of the magnet sub-systems were performed at low current before starting the ramps up to higher field. It appeared clearly that the end of the field ramp down to zero was too long to be compatible with the detector commissioning and operations plans. It was decided to perform an upgrade to keep the ramp down from 3.8T to zero within 4 hours. On July 10th, when a field of 1.5T was reached, small movements were observed in the forward region support table and it was decided to fix this problem before going to higher field. At the end of July the ramps could be resumed. On July 28th, the field was at 3.8T and the summer CRAFT exercise could start. This run in August went smoothly until a general CERN wide power cut took place on August 3rd, due to an insulation fault on the high voltage network outside point 5. It affected the magnet powering electrical circuit, as it caused the opening of the main circuit breakers, resulting in a fast du...

  3. Prevalence of human T-cell lymphotropic virus types 1 and 2 in blood donors of the Caruaru Blood Center (Hemope

    Directory of Open Access Journals (Sweden)

    Waleska Mayara Gomes de Lima

    2013-01-01

    Full Text Available BACKGROUND: There is difficulty in gathering data on the prevalence of human T-cell lymphotropic virus in blood donors as confirmatory testing is not mandatory in Brazil. This suggests there may be an underreporting of the prevalence. OBJECTIVE: To estimate the prevalence of human T-cell lymphotropic virus types 1 and 2 in donors of a blood bank in Caruaru, Brazil. METHODS: This was an observational, epidemiological, descriptive, longitudinal and retrospective study with information about the serology of donors of the Caruaru Blood Center, Fundação de Hematologia e Hemoterapia de Pernambuco (Hemope from May 2006 to December 2010. The data were analyzed using the Excel 2010 computer program (Microsoft Office(r. RESULTS: Of 61,881 donors, 60 (0.096% individuals were identified as potential carriers of human T-cell lymphotropic virus types 1 and 2. Of these, 28 (0.045% were positive and 32 (0.051% had inconclusive results in the serological screening. Forty-five (0.072% were retested; 17 were positive (0.027% and 3 inconclusive (0.005%. After confirmatory tests, 8 were positive (0.013%. Six (75% of the confirmed cases were women. CONCLUSION: Epidemiological surveys like this are very important in order to create campaigns to attract donors and reduce the costs of laboratory tests.

  4. Prevalence of human T-cell lymphotropic virus types 1 and 2 in blood donors of the Caruaru Blood Center (Hemope).

    Science.gov (United States)

    de Lima, Waleska Mayara Gomes; Esteves, Fabrício Andrade Martins; Torres, Maria do Carmo Morais Rodrigues; Pires, Edna Suely Feitosa

    2013-01-01

    There is difficulty in gathering data on the prevalence of human T-cell lymphotropic virus in blood donors as confirmatory testing is not mandatory in Brazil. This suggests there may be an underreporting of the prevalence. To estimate the prevalence of human T-cell lymphotropic virus types 1 and 2 in donors of a blood bank in Caruaru, Brazil. This was an observational, epidemiological, descriptive, longitudinal and retrospective study with information about the serology of donors of the Caruaru Blood Center, Fundação de Hematologia e Hemoterapia de Pernambuco (Hemope) from May 2006 to December 2010. The data were analyzed using the Excel 2010 computer program (Microsoft Office(®)). Of 61,881 donors, 60 (0.096%) individuals were identified as potential carriers of human T-cell lymphotropic virus types 1 and 2. Of these, 28 (0.045%) were positive and 32 (0.051%) had inconclusive results in the serological screening. Forty-five (0.072%) were retested; 17 were positive (0.027%) and 3 inconclusive (0.005%). After confirmatory tests, 8 were positive (0.013%). Six (75%) of the confirmed cases were women. Epidemiological surveys like this are very important in order to create campaigns to attract donors and reduce the costs of laboratory tests.

  5. MAGNET

    CERN Multimedia

    Benoit Curé

    The magnet subsystems resumed operation early this spring. The vacuum pumping was restarted mid March, and the cryogenic power plant was restarted on March 30th. Three and a half weeks later, the magnet was at 4.5 K. The vacuum pumping system is performing well. One of the newly installed vacuum gauges had to be replaced at the end of the cool-down phase, as the values indicated were not coherent with the other pressure measurements. The correction had to be implemented quickly to be sure no helium leak could be at the origin of this anomaly. The pressure measurements have been stable and coherent since the change. The cryogenics worked well, and the cool-down went quite smoothly, without any particular difficulty. The automated start of the turbines had to be fine-tuned to get a smooth transition, as it was observed that the cooling power delivered by the turbines was slightly higher than needed, causing the cold box to stop automatically. This had no consequence as the cold box safety system acts to keep ...

  6. MAGNET

    CERN Multimedia

    B. Curé

    During the winter shutdown, the magnet subsystems went through a full maintenance. The magnet was successfully warmed up to room temperature beginning of December 2008. The vacuum was broken later on by injecting nitrogen at a pressure just above one atmosphere inside the vacuum tank. This was necessary both to prevent any accidental humidity ingress, and to allow for a modification of the vacuum gauges on the vacuum tank and maintenance of the diffusion pumps. The vacuum gauges had to be changed, because of erratic variations on the measurements, causing spurious alarms. The new type of vacuum gauges has been used in similar conditions on the other LHC experiments and without problems. They are shielded against the stray field. The lubricants of the primary and diffusion pumps have been changed. Several minor modifications were also carried out on the equipment in the service cavern, with the aim to ease the maintenance and to allow possible intervention during operation. Spare sensors have been bought. Th...

  7. Short Communication: Current Prevalence and Risk Factors Associated with Human T Lymphotropic Virus Type 1 and Human T Lymphotropic Virus Type 2 Infections Among HIV/AIDS Patients in São Paulo, Brazil.

    Science.gov (United States)

    Caterino-de-Araujo, Adele; Sacchi, Cláudio Tavares; Gonçalves, Maria Gisele; Campos, Karoline Rodrigues; Magri, Mariana Cavalheiro; Alencar, Wong Kuen

    2015-05-01

    During the 1990s, high prevalences of HIV/human T lymphotropic virus type 1 (HTLV-1) and HIV/human T lymphotropic virus type 2 (HTLV-2) coinfections were detected in São Paulo, Brazil in association with intravenous drug use (IDU). The current prevalences and risk factors for HIV/HTLV-1/-2 were evaluated in 1,608 patients attending the AIDS/STD Reference and Training Center in São Paulo. Blood samples were analyzed for HTLV-1/2-specific antibodies using enzyme immunoassays (EIA Murex HTLV-I+II, Diasorin, and Gold ELISA HTLV-I+II, REM) and immunoblotting (HTLV Blot 2.4, MP Biomedicals and INNO-LIA HTLV-I/II, Innogenetics) and for the pol proviral DNA segments of HTLV-1 and HTLV-2 by "in-house" real-time PCR. These analyses revealed that 50 (3.11%) of the samples were HTLV positive, including 25 (1.55%) that were HTLV-1 positive, 21 (1.31%) that were HTLV-2 positive, and 4 (0.25%) that were HTLV positive (untypeable). The median age of the HIV/HTLV-coinfected individuals was 50 years versus 44 years in the overall population (p=0.000). The risk factors associated with HIV/HTLV-1/-2 coinfections were female gender (OR 3.26, 1.78-5.95), black/pardo color (OR 2.21, 1.21-4.03), infection with hepatitis B virus (HBV) (OR 4.27, 2.32-7.87) or hepatitis C virus (HCV) (OR 24.40, 12.51-48.11), and intravenous drug use (IDU) (OR 30.01, 15.21-59.29). The current low prevalence of HTLV-1/2 in HIV-infected patients in São Paulo could be explained in part by programs providing IDUs with sterile needles and syringes and changes in the drug usage patterns of individuals from injecting cocaine to smoking crack cocaine.

  8. Molecular epidemiology of endemic human T-lymphotropic virus type 1 in a rural community in Guinea-Bissau.

    Directory of Open Access Journals (Sweden)

    Carla van Tienen

    Full Text Available Human T-Lymphotropic Virus Type 1 (HTLV-1 infection causes lethal adult T-cell leukemia (ATL and severely debilitating HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP in up to 5% of infected adults. HTLV-1 is endemic in parts of Africa and the highest prevalence in West Africa (5% has been reported in Caio, a rural area in the North-West of Guinea-Bissau. It is not known which HTLV-1 variants are present in this community. Sequence data can provide insights in the molecular epidemiology and help to understand the origin and spread of HTLV-1.To gain insight into the molecular diversity of HTLV-1 in West Africa.HTLV-1 infected individuals were identified in community surveys between 1990-2007. The complete Long Terminal Repeat (LTR and p24 coding region of HTLV-1 was sequenced from infected subjects. Socio-demographic data were obtained from community census and from interviews performed by fieldworkers. Phylogenetic analyses were performed to characterize the relationship between the Caio HTLV-1 and HTLV-1 from other parts of the world.LTR and p24 sequences were obtained from 72 individuals (36 LTR, 24 p24 only and 12 both. Consistent with the low evolutionary change of HTLV-1, many of the sequences from unrelated individuals showed 100% nucleotide identity. Most (45 of 46 of the LTR sequences clustered with the Cosmopolitan HTLV-1 subtype 1a, subgroup D (1aD. LTR and p24 sequences from two subjects were divergent and formed a significant cluster with HTLV-1 subtype 1g, and with the most divergent African Simian T-cell Lymphotropic Virus, Tan90.The Cosmopolitan HTLV-1 1aD predominates in this rural West African community. However, HTLV-1 subtype 1g is also present. This subtype has not been described before in West Africa and may be more widespread than previously thought. These data are in line with the hypothesis that multiple monkey-to-man zoonotic events are contributing to HTLV-1 diversity.

  9. MAGNET

    CERN Multimedia

    Benoit Curé

    2013-01-01

    Maintenance work and consolidation activities on the magnet cryogenics and its power distribution are progressing according to the schedules. The manufacturing of the two new helium compressor frame units has started. The frame units support the valves, all the sensors and the compressors with their motors. This activity is subcontracted. The final installation and the commissioning at CERN are scheduled for March–April 2014. The overhauls of existing cryogenics equipment (compressors, motors) are in progress. The reassembly of the components shall start in early 2014. The helium drier, to be installed on the high-pressure helium piping, has been ordered and will be delivered in the first trimester of 2014. The power distribution for the helium compressors in SH5 on the 3.3kV network is progressing. The 3.3kV switches, between each compressor and its hot spare compressor, are being installed, together with the power cables for the new compressors. The 3.3kV electrical switchboards in SE5 will ...

  10. MAGNET

    CERN Multimedia

    Benoit Curé

    The cooling down to the nominal temperature of 4.5 K was achieved at the beginning of August, in conjunction with the completion of the installation work of the connection between the power lines and the coil current leads. The temperature gradient on the first exchanger of the cold box is now kept within the nominal range. A leak of lubricant on a gasket of the helium compressor station installed at the surface was observed and several corrective actions were necessary to bring the situation back to normal. The compressor had to be refilled with lubricant and a regeneration of the filters and adsorbers was necessary. The coil cool down was resumed successfully, and the cryogenics is running since then with all parameters being nominal. Preliminary tests of the 20kA coil power supply were done earlier at full current through the discharge lines into the dump resistors, and with the powering busbars from USC5 to UXC5 without the magnet connected. On Monday evening August 25th, at 8pm, the final commissionin...

  11. MAGNET

    CERN Multimedia

    B. Curé

    The first phase of the commissioning ended in August by a triggered fast dump at 3T. All parameters were nominal, and the temperature recovery down to 4.5K was carried out in two days by the cryogenics. In September, series of ramps were achieved up to 3 and finally 3.8T, while checking thoroughly the detectors in the forward region, measuring any movement of and around the HF. After the incident of the LHC accelerator on September 19th, corrective actions could be undertaken in the forward region. When all these displacements were fully characterized and repetitive, with no sign of increments in displacement at each field ramp, it was possible to start the CRAFT, Cosmic Run at Four Tesla (which was in fact at 3.8T). The magnet was ramped up to 18.16kA and the 3 week run went smoothly, with only 4 interruptions: due to the VIP visits on 21st October during the LHC inauguration day; a water leak on the cooling demineralized water circuit, about 1 l/min, that triggered a stop of the cooling pumps, and resulte...

  12. Magnetic

    Science.gov (United States)

    Aboud, Essam; El-Masry, Nabil; Qaddah, Atef; Alqahtani, Faisal; Moufti, Mohammed R. H.

    2015-06-01

    The Rahat volcanic field represents one of the widely distributed Cenozoic volcanic fields across the western regions of the Arabian Peninsula. Its human significance stems from the fact that its northern fringes, where the historical eruption of 1256 A.D. took place, are very close to the holy city of Al-Madinah Al-Monawarah. In the present work, we analyzed aeromagnetic data from the northern part of Rahat volcanic field as well as carried out a ground gravity survey. A joint interpretation and inversion of gravity and magnetic data were used to estimate the thickness of the lava flows, delineate the subsurface structures of the study area, and estimate the depth to basement using various geophysical methods, such as Tilt Derivative, Euler Deconvolution and 2D modeling inversion. Results indicated that the thickness of the lava flows in the study area ranges between 100 m (above Sea Level) at the eastern and western boundaries of Rahat Volcanic field and getting deeper at the middle as 300-500 m. It also showed that, major structural trend is in the NW direction (Red Sea trend) with some minor trends in EW direction.

  13. Long-term increases in lymphocytes and platelets in human T-lymphotropic virus type II infection.

    Science.gov (United States)

    Bartman, Melissa T; Kaidarova, Zhanna; Hirschkorn, Dale; Sacher, Ronald A; Fridey, Joy; Garratty, George; Gibble, Joan; Smith, James W; Newman, Bruce; Yeo, Anthony E; Murphy, Edward L

    2008-11-15

    Human T-lymphotropic viruses types I and II (HTLV-I and HTLV-II) cause chronic infections of T lymphocytes that may lead to leukemia and myelopathy. However, their long-term effects on blood counts and hematopoiesis are poorly understood. We followed 151 HTLV-I-seropositive, 387 HTLV-II-seropositive, and 799 HTLV-seronegative former blood donors from 5 U.S. blood centers for a median of 14.0 years. Complete blood counts were performed every 2 years. Multivariable repeated measures analyses were conducted to evaluate the independent effect of HTLV infection and potential confounders on 9 hematologic measurements. Participants with HTLV-II had significant (P platelet counts (+16 544 and +21 657 cells/mm(3); P platelet count and lymphocyte counts, and to increases in MCV and monocytes. Sex, race, smoking, and alcohol consumption all had significant effects on blood counts. The HTLV-II effect on lymphocytes is novel and may be related to viral transactivation or immune response. HTLV-I and HTLV-II associations with higher platelet counts suggest viral effects on hematopoietic growth factors or cytokines.

  14. Highly endemic human T-lymphotropic virus type II (HTLV-II) infection in a Venezuelan Guahibo Amerindian group.

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    Leon-Ponte, M; Noya, O; Bianco, N; Echeverría de Perez, G

    1996-11-01

    Sera from 166 Guahibo Indians (55% of the population) living in southwest Venezuela were screened by enzyme-linked immunoassay for antibodies to human T-cell lymphotropic virus (HTLV) I and II. Positive samples were confirmed by immunofluorescence and Western blot. Forty-one Guahibos (24.8%) were found to be seropositive. Polymerase chain reaction (PCR) analysis of proviral DNA in mononuclear cell lysates revealed the virus to be HTLV-II. Prevalence increased with age, and sexual contact with HTLV-II-seropositive partners was identified as a risk factor for infection. PCR amplification of a region of the pol gene, utilizing the primer pair SK110/SK111, with subsequent digestion of the 140-base-pair amplification products with HinfI and MseI restriction enzymes, showed an HTLV-II subtype-b restriction pattern in all cases. These data suggest that the substrain infecting this Guahibo community belongs to the b subtype, the most frequent among Paleo-Amerindian populations.

  15. Clinical pathophysiology of human T-lymphotropic virus-type1-associated myelopathy/tropical spastic paraparesis

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    Yoshihisa eYamano

    2012-11-01

    Full Text Available Human T-lymphotropic virus type 1 (HTLV-1, a human retrovirus, is the causative agent of a progressive neurological disease termed HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP. HAM/TSP is a chronic inflammatory disease of the central nervous system and is characterized by unremitting myelopathic symptoms such as spastic paraparesis, lower limb sensory disturbance, and bladder/bowel dysfunction. Approximately 0.25%–3.8% of HTLV-1-infected individuals develop HAM/TSP, which is more common in women than in men. Since the discovery of HAM/TSP, significant advances have been made with respect to elucidating the virological, molecular, and immunopathological mechanisms underlying this disease. These findings suggest that spinal cord invasion by HTLV-1-infected T cells triggers a strong virus-specific immune response and increases proinflammatory cytokine and chemokine production, leading to chronic lymphocytic inflammation and tissue damage in spinal cord lesions. However, little progress has been made in the development of an optimal treatment for HAM/TSP, more specifically in the identification of biomarkers for predicting disease progression and of molecular targets for novel therapeutic strategies targeting the underlying pathological mechanisms. This review summarizes current clinical and pathophysiological knowledge on HAM/TSP and discusses future focus areas for research on this disease.

  16. Analysis of human T-cell lymphotropic virus in CD25+ anaplastic large cell lymphoma in children.

    Science.gov (United States)

    Gualco, Gabriela; Chioato, Lucimara; Weiss, Lawrence M; Harrington, William J; Bacchi, Carlos E

    2009-07-01

    Anaplastic large cell lymphoma (ALCL) is recognized as 2 distinct diseases: anaplastic lymphoma kinase (ALK)+ ALCL and ALK- ALCL. ALK+ ALCL occurs in younger patients and has a better prognosis. Human T-cell lymphotropic virus (HTLV-1) is linked to the development of adult T-cell leukemia/lymphoma (ATLL), which frequently expresses CD25. CD25 is significantly expressed in childhood ALCL. In Brazil, HTLV-1 infection is endemic, and vertical transmission is responsible for spread to children. Of HTLV-1 carriers, 90% or more remain asymptomatic. Some cases of adult HTLV-1-related lymphomas have characteristics of ALCL but are considered CD30+ ATLL subtypes. No similar cases have been described in children. We analyzed 33 cases of pediatric ALCL, CD25+ and CD25-, for proviral HTLV-1 DNA. All cases corresponded to the common histologic ALCL type and were CD30+ in virtually all neoplastic cells. ALK expression was observed in 31 (94%) of 33 cases; CD25 was positive in 27 (82%), including 1 ALK- ALCL case. There was a strong positive correlation between ALK and CD25 expression. None of the cases showed proviral HTLV-1 DNA. ALCL in children has no relationship with HTLV-1; the frequent CD25 expression must be explained by a mechanism different from that in ATLL.

  17. Leukotrienes are upregulated and associated with human T-lymphotropic virus type 1 (HTLV-1-associated neuroinflammatory disease.

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    Bruno Caetano Trindade

    Full Text Available Leukotrienes (LTs are lipid mediators involved in several inflammatory disorders. We investigated the LT pathway in human T-lymphotropic virus type 1 (HTLV-1 infection by evaluating LT levels in HTLV-1-infected patients classified according to the clinical status as asymptomatic carriers (HACs and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP patients. Bioactive LTB(4 and CysLTs were both increased in the plasma and in the supernatant of peripheral blood mononuclear cell cultures of HTLV-1-infected when compared to non-infected. Interestingly, CysLT concentrations were increased in HAM/TSP patients. Also, the concentration of plasma LTB(4 and LTC(4 positively correlated with the HTLV-1 proviral load in HTLV-1-infected individuals. The gene expression levels of LT receptors were differentially modulated in CD4(+ and CD8(+ T cells of HTLV-1-infected patients. Analysis of the overall plasma signature of immune mediators demonstrated that LT and chemokine amounts were elevated during HTLV-1 infection. Importantly, in addition to CysLTs, IP-10 was also identified as a biomarker for HAM/TSP activity. These data suggest that LTs are likely to be associated with HTLV-1 infection and HAM/TSP development, suggesting their putative use for clinical monitoring.

  18. Viral Causes of Lymphoma: The History of Epstein-Barr Virus and Human T-Lymphotropic Virus 1

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    Daniel Esau

    2017-09-01

    Full Text Available In 1964, Epstein, Barr, and Achong published a report outlining their discovery of viral particles in lymphoblasts isolated from a patient with Burkitt lymphoma. The Epstein-Barr virus (EBV was the first human cancer virus to be described, and its discovery paved the way for further investigations into the oncogenic potential of viruses. In the decades following the discovery of EBV, multinational research efforts led to the discovery of further viral causes of various human cancers. Lymphomas are perhaps the cancer type that is most closely associated with oncogenic viruses: infection with EBV, human T-lymphotropic virus 1 (HTLV-1, human immunodeficiency virus (HIV, Kaposi sarcoma-associated herpesvirus/human herpesvirus 8, and hepatitis C virus have all been associated with lymphomagenesis. Lymphomas have also played an important role in the history of oncoviruses, as both the first human oncovirus (EBV and the first human retrovirus (HTLV-1 were discovered through isolates taken from patients with unique lymphoma syndromes. The history of the discovery of these 2 key oncoviruses is presented here, and their impact on further medical research, using the specific example of HIV research, is briefly discussed.

  19. Viral Causes of Lymphoma: The History of Epstein-Barr Virus and Human T-Lymphotropic Virus 1.

    Science.gov (United States)

    Esau, Daniel

    2017-01-01

    In 1964, Epstein, Barr, and Achong published a report outlining their discovery of viral particles in lymphoblasts isolated from a patient with Burkitt lymphoma. The Epstein-Barr virus (EBV) was the first human cancer virus to be described, and its discovery paved the way for further investigations into the oncogenic potential of viruses. In the decades following the discovery of EBV, multinational research efforts led to the discovery of further viral causes of various human cancers. Lymphomas are perhaps the cancer type that is most closely associated with oncogenic viruses: infection with EBV, human T-lymphotropic virus 1 (HTLV-1), human immunodeficiency virus (HIV), Kaposi sarcoma-associated herpesvirus/human herpesvirus 8, and hepatitis C virus have all been associated with lymphomagenesis. Lymphomas have also played an important role in the history of oncoviruses, as both the first human oncovirus (EBV) and the first human retrovirus (HTLV-1) were discovered through isolates taken from patients with unique lymphoma syndromes. The history of the discovery of these 2 key oncoviruses is presented here, and their impact on further medical research, using the specific example of HIV research, is briefly discussed.

  20. Radioimmunoassay and enzyme-linked immunoassay of antibodies to the core protein (P24) of human T-lymphotropic virus (HTLV III). [Acquired immunodeficiency syndrome (AIDS)

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    Neurath, A.R.; Strick, N.; Sproul, P.

    1985-05-01

    Human T-cell lymphotropic viruses designated HTLV III or LAV are considered to represent the causative agents of the acquired immunodeficiency syndrome (AIDS). Therefore a simple direct RIA or ELISA method for antibodies to distinct epitopes of HTLV III/LAV structural components would be of great value. The authors describe RIA and ELISA assays which obviate the need for purified virus or virus proteins, do not utilize infected cells and thus do not diminish the source for continuous production of viral antigens and are specific for a major core protein of HTLV III/LAV.

  1. Physiotherapy for human T-lymphotropic virus 1-associated myelopathy: review of the literature and future perspectives

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    Sá KN

    2015-02-01

    Full Text Available Katia N Sá,1 Maíra C Macêdo,1 Rosana P Andrade,2 Selena D Mendes,1 José V Martins,3 Abrahão F Baptista1,4 1Neuromusculoskeletal Research Group, Bahian School of Medicine and Human Health, Salvador, Brazil; 2Edgard Santos University Hospital, Federal University of Bahia, Salvador, 3Deolindo Couto Institute of Neurology, Federal University of Rio de Janeiro, Rio de Janeiro, 4Biomorphology Department, Health Sciences Institute, Federal University of Bahia, Salvador, Brazil Abstract: Human T-lymphotropic virus 1 (HTLV-1 infection may be associated with damage to the spinal cord – HTLV-associated myelopathy/tropical spastic paraparesis – and other neurological symptoms that compromise everyday life activities. There is no cure for this disease, but recent evidence suggests that physiotherapy may help individuals with the infection, although, as far as we are aware, no systematic review has approached this topic. Therefore, the objective of this review is to address the core problems associated with HTLV-1 infection that can be detected and treated by physiotherapy, present the results of clinical trials, and discuss perspectives on the development of knowledge in this area. Major problems for individuals with HTLV-1 are pain, sensory-motor dysfunction, and urinary symptoms. All of these have high impact on quality of life, and recent clinical trials involving exercises, electrotherapeutic modalities, and massage have shown promising effects. Although not influencing the basic pathologic disturbances, a physiotherapeutic approach seems to be useful to detect specific problems related to body structures, activity, and participation related to movement in HTLV-1 infection, as well as to treat these conditions. Keywords: HTLV-1, HAM/TSP, physical therapy modalities, quality of life, pain, sensory-motor dysfunction, urinary symptoms

  2. Detection of DNA of Lymphotropic Herpesviruses in Plasma of Human Immunodeficiency Virus-Infected Patients: Frequency and Clinical Significance

    Science.gov (United States)

    Broccolo, Francesco; Bossolasco, Simona; Careddu, Anna M.; Tambussi, Giuseppe; Lazzarin, Adriano; Cinque, Paola

    2002-01-01

    The frequency and clinical significance of detection of DNA of cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), HHV-7, and HHV-8 in plasma were investigated by PCR. The plasma was obtained from 120 selected human immunodeficiency virus (HIV)-infected patients, of whom 75 had AIDS-related manifestations, 32 had primary HIV infection (PHI), and 13 had asymptomatic infections. Nested PCR analysis revealed that none of the lymphotropic herpesviruses tested were found in patients with PHI, in asymptomatic HIV-positive individuals, or in HIV-negative controls. By contrast, DNA of one or more of the viruses was found in 42 (56%) of 75 patients with AIDS-related manifestations, including CMV disease (CMV-D) or AIDS-related tumors. The presence of CMV DNA in plasma was significantly associated with CMV-D (P < 0.001). By contrast, EBV detection was not significantly associated with AIDS-related lymphomas (P = 0.31). Interestingly, the presence of HHV-8 DNA in plasma was significantly associated with Kaposi's sarcoma (KS) disease (P < 0.001) and with the clinical status of KS patients (P < 0.001). CMV (primarily), EBV, and HHV-8 were the viruses most commonly reactivated in the context of severe immunosuppression (P < 0.05). In contrast, HHV-6 and HHV-7 infections were infrequent at any stage of disease. In conclusion, plasma PCR was confirmed to be useful in the diagnosis of CMV-D but not in that of tumors or other conditions possibly associated with EBV, HHV-6, and HHV-7. Our findings support the hypothesis of a direct involvement of HHV-8 replication in KS pathogenesis, thus emphasizing the usefulness of sensitive and specific diagnostic tests to monitor HHV-8 infection. PMID:12414753

  3. Prevalence of human T-cell lymphotropic virus (HTLV-1/2) in individuals from public health centers in Mozambique.

    Science.gov (United States)

    Caterino-de-Araujo, Adele; Magri, Mariana Cavalheiro; Costa, Emanuela Avelar Silva; Manuel, Rolanda Carmen Rafael

    2010-05-01

    The prevalence of human T-cell lymphotropic viruses types 1 and 2 (HTLV-1/2) in Mozambique is not known. The present study examined blood samples from 208, 226, and 318 individuals from Northern, Central, and Southern Mozambique, respectively, of all socioeconomic and demographic strata attending public health centers in Mozambique for HTLV-1/2-specific antibodies. Serum samples were assessed for HIV- and HTLV-1/2-specific antibodies by using enzyme immunoassays, and infections with HTLV-1 and -2 were confirmed by using Western blot. An overall HTLV-1/2 prevalence of 2.3% (2.9% in female and 1.1% in male subjects) was observed, and the prevalence of infection increased with age. Regional variation in the prevalence of HIV and HTLV-1/2 was observed; 32.2%, 65.5%, and 44% of individuals tested HIV positive in Northern, Central, and Southern Mozambique, respectively, and 2.4%, 3.9%, and 0.9% tested HTLV-1/2 positive in the same regions. HTLV-1 infection was confirmed in these individuals. No association between HTLV-1 infection and sociodemographic variables or HIV status was detected, although the low number of HTLV-1-positive cases did not allow robust statistical analyses. The results obtained suggest different risk factors and epidemiologic correlates of HIV and HTLV-1 transmission in Mozambique. Furthermore, our results suggested that North and Central Mozambique should be considered endemic regions for HTLV-1 infection. As no cases of HTLV-2 were detected, HTLV-2 appears to have not been introduced into Mozambique.

  4. Critical role of human T-lymphotropic virus type 1 accessory proteins in viral replication and pathogenesis.

    Science.gov (United States)

    Albrecht, Björn; Lairmore, Michael D

    2002-09-01

    Human T-cell lymphotropic virus type 1 (HTLV-1) infection is associated with a diverse range of lymphoproliferative and neurodegenerative diseases, yet pathogenic mechanisms induced by the virus remain obscure. This complex retrovirus contains typical structural and enzymatic genes but also unique regulatory and accessory genes in four open reading frames (ORFs) of the pX region of the viral genome (pX ORFs I to IV). The regulatory proteins encoded by pX ORFs III and IV, Tax and Rex, respectively, have been extensively characterized. In contrast the contribution of the four accessory proteins p12(I), p27(I), p13(II), and p30(II), encoded by pX ORFs I and II, to viral replication and pathogenesis remained unclear. Proviral clones that are mutated in either pX ORF I or II, while fully competent in cell culture, are severely limited in their replicative capacity in a rabbit model. Emerging evidence indicates that the HTLV-1 accessory proteins are critical for establishment of viral infectivity, enhance T-lymphocyte activation, and potentially alter gene transcription and mitochondrial function. HTLV-1 pX ORF I expression is critical to the viral infectivity in resting primary lymphocytes, suggesting a role for p12(I) in lymphocyte activation. The endoplasmic reticulum and cis-Golgi localizing p12(I), encoded from pX ORF I, activates NFAT, a key T-cell transcription factor, through calcium-mediated signaling pathways and may lower the threshold of lymphocyte activation via the JAK/STAT pathway. In contrast p30(II) localizes to the nucleus and represses viral promoter activity, but may regulate cellular gene expression through p300/CBP or related coactivators of transcription. p13(II) targets mitochondrial proteins, where it alters the organelle morphology and may influence energy metabolism. Collectively, studies of the molecular functions of the HTLV-1 accessory proteins provide insight into strategies used by retroviruses that are associated with lymphoproliferative

  5. Seroepidemiology of human T-cell lymphotropic virus type-I in blood donors of Northeastern Iran, Sabzevar

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    Mahtab Maghsudlu

    2015-01-01

    Full Text Available Background and Objectives: Human T-cell lymphotropic virus type-I (HTLV-I infection is considered as a public health challenge in endemic areas. The virus is associated with severe diseases, such as adult T-cell leukemia/lymphoma, and HTLV-I-associated myelopathy/tropical spastic paraparesis. One of the major routes of the HTLV-I transmission includes blood transfusion. Sabzevar is located in the endemic region of HTLV-I infection. The aim of the present study was to determine the seroprevalence of HTLV-I infection in the blood donors in Sabzevar. Materials and Methods: A total of 35,067 blood donors in Sabzevar from March 2009 to April 2012 who were screened with HTLV-I on the enzyme-linked immunosorbent assay screening test were included in this survey. Reactive samples that confirmed by western blot were considered to be seropositive cases. The required data were obtained from blood donors′ database of blood transfusion service. Results: The overall prevalence of HTLV-1 based on the positive result of western blot test was 0.14%. The seropositive donors aged 17-59 years with a mean age of 38.10 ± 11.82. The prevalence rates of HTLV-I infection in 3 years of study were 0.19%, 0.14%, and 0.09%, respectively. A significant relation between age, sex, educational level, and history of blood donation was observed with seropositivity of HTLV-I. Conclusion: The improvement of donor selection and laboratory screening caused a decline in the prevalence of infection in blood donors. Given the lower prevalence of infection in regular donors with lower age and higher educational level, more efforts should be done to attract blood donors from these populations.

  6. Barefoot Plantar Pressure Indicates Progressive Neurological Damage in Patients with Human T-Cell Lymphotropic Virus Type 1 Infection.

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    Beatriz Helena B Vasconcelos

    Full Text Available The human T-Cell Lymphotropic Virus Type 1 (HTLV-1 is a retrovirus associated with neurological alterations; individuals with HTLV-1 infection may develop HTLV-1 associated myelopathy / tropical spastic paraparesis (HAM/TSP. Frequent neurological complaints include foot numbness and leg weakness. In this study, we compared the distribution of the body weight on different areas of the foot in HTLV-1 patients with HAM/TSP, asymptomatic HTLV-1 patients, and healthy individuals.We studied 36 HTLV-1 infected patients, who were divided in two groups of 18 patients each based on whether or not they had been diagnosed with HAM/TSP, and 17 control subjects. The evaluation included an interview on the patient's clinical history and examinations of the patient's reflexes, foot skin tactile sensitivity, and risk of falling. The pressure distribution on different areas of the foot was measured with baropodometry, using a pressure platform, while the patients had their eyes open or closed.The prevalence of neurological disturbances-altered reflexes and skin tactile sensitivity and increased risk of falling-was higher in HTLV-1 HAM/TSP patients than in HTLV-1 asymptomatic patients. The medium and maximum pressure values were higher in the forefoot than in the midfoot and hindfoot in both HTLV-1 groups. In addition, the pressure on the hindfoot was lower in HAM/TSP patients compared to control subjects.The neurological disturbances associated with HTLV-1 infection gradually worsened from HTLV-1 asymptomatic patients to HAM/TSP patients. Baropodometry is a valuable tool to establish the extent of neurological damage in patients suffering from HTLV-1 infection.

  7. Constitutive Release of IFNγ and IL2 from Peripheral Blood Mononuclear Cells of Rhesus Macaques (Macaca mulatta) Infected with Simian T-Lymphotropic Virus Type 1

    Science.gov (United States)

    Yee, JoAnn L; Montiel, Nestor A; Ardeshr, Amir; Lerche, Nicholas W

    2013-01-01

    Simian T-cell lymphotropic viruses (STLV), the nonhuman primate counterparts of human T-cell lymphotropic viruses (HTLV), are endemic in many populations of African and Asian monkeys and apes. Although an etiologic link between STLV1 infection and lymphoproliferative disorders such as malignant lymphomas has been suggested in some nonhuman primate species, most STLV infections are inapparent, and infected animals remain clinically healthy. The retroviral transactivator, tax, is well known to increase transcription of viral and cellular genes, resulting in altered cytokine profiles. This study compared the cytokine profiles of peripheral blood mononuclear cell (PBMC) cultures from 25 STLV1-seropositive rhesus macaques (Macaca mulatta) with those of age- and sex-matched seronegative controls. IFNγ, TNFα, IL10, and IL2 levels in unstimulated PBMC culture supernatants were measured at 24, 48, and 72 h by using enzyme immunoassays. IFNγ concentrations were found significantly higher in the supernatants of PBMC cultures of seropositive monkeys as compared with seronegative controls. In addition, although IL2 concentrations were not significantly elevated in the supernatants of PBMC cultures of all seropositive monkeys as compared with all seronegative controls, IL2 levels were increased in a subset of 5 pairs. Increased constitutive cytokine release occurred in the absence of spontaneous proliferation. The increased constitutive release of IFNγ and IL2 suggests that STLV1 alters immune functions in infected but clinically healthy rhesus macaques and further characterizes STLV1 infection of rhesus macaques as a potential model for human HTLV1 infection. PMID:24326227

  8. Quantification of Human T-lymphotropic virus type I (HTLV-I) provirus load in a rural West African population: no enhancement of human immunodeficiency virus type 2 pathogenesis, but HTLV-I provirus load relates to mortality

    DEFF Research Database (Denmark)

    Ariyoshi, K; Berry, N; Cham, F;

    2003-01-01

    Human T-lymphotropic virus type I (HTLV-I) provirus load was examined in a cohort of a population in Guinea-Bissau among whom human immunodeficiency virus (HIV) type 2 is endemic. Geometric mean of HIV-2 RNA load among HTLV-I-coinfected subjects was significantly lower than that in subjects infec...

  9. Ancient, independent evolution and distinct molecular features of the novel human T-lymphotropic virus type 4

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    Wolfe Nathan D

    2009-02-01

    Full Text Available Abstract Background Human T-lymphotropic virus type 4 (HTLV-4 is a new deltaretrovirus recently identified in a primate hunter in Cameroon. Limited sequence analysis previously showed that HTLV-4 may be distinct from HTLV-1, HTLV-2, and HTLV-3, and their simian counterparts, STLV-1, STLV-2, and STLV-3, respectively. Analysis of full-length genomes can provide basic information on the evolutionary history and replication and pathogenic potential of new viruses. Results We report here the first complete HTLV-4 sequence obtained by PCR-based genome walking using uncultured peripheral blood lymphocyte DNA from an HTLV-4-infected person. The HTLV-4(1863LE genome is 8791-bp long and is equidistant from HTLV-1, HTLV-2, and HTLV-3 sharing only 62–71% nucleotide identity. HTLV-4 has a prototypic genomic structure with all enzymatic, regulatory, and structural proteins preserved. Like STLV-2, STLV-3, and HTLV-3, HTLV-4 is missing a third 21-bp transcription element found in the long terminal repeats of HTLV-1 and HTLV-2 but instead contains unique c-Myb and pre B-cell leukemic transcription factor binding sites. Like HTLV-2, the PDZ motif important for cellular signal transduction and transformation in HTLV-1 and HTLV-3 is missing in the C-terminus of the HTLV-4 Tax protein. A basic leucine zipper (b-ZIP region located in the antisense strand of HTLV-1 and believed to play a role in viral replication and oncogenesis, was also found in the complementary strand of HTLV-4. Detailed phylogenetic analysis shows that HTLV-4 is clearly a monophyletic viral group. Dating using a relaxed molecular clock inferred that the most recent common ancestor of HTLV-4 and HTLV-2/STLV-2 occurred 49,800 to 378,000 years ago making this the oldest known PTLV lineage. Interestingly, this period coincides with the emergence of Homo sapiens sapiens during the Middle Pleistocene suggesting that early humans may have been susceptible hosts for the ancestral HTLV-4. Conclusion The

  10. Genetic characterization of human T-cell lymphotropic virus type 1 in Mozambique: transcontinental lineages drive the HTLV-1 endemic.

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    Ana Carolina P Vicente

    Full Text Available BACKGROUND: Human T-Cell Lymphotropic Virus Type 1 (HTLV-1 is the etiological agent of adult T-cell leukemia (ATL and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP. It has been estimated that 10-20 million people are infected worldwide, but no successful treatment is available. Recently, the epidemiology of this virus was addressed in blood donors from Maputo, showing rates from 0.9 to 1.2%. However, the origin and impact of HTLV endemic in this population is unknown. OBJECTIVE: To assess the HTLV-1 molecular epidemiology in Mozambique and to investigate their relationship with HTLV-1 lineages circulating worldwide. METHODS: Blood donors and HIV patients were screened for HTLV antibodies by using enzyme immunoassay, followed by Western Blot. PCR and sequencing of HTLV-1 LTR region were applied and genetic HTLV-1 subtypes were assigned by the neighbor-joining method. The mean genetic distance of Mozambican HTLV-1 lineages among the genetic clusters were determined. Human mitochondrial (mt DNA analysis was performed and individuals classified in mtDNA haplogroups. RESULTS: LTR HTLV-1 analysis demonstrated that all isolates belong to the Transcontinental subgroup of the Cosmopolitan subtype. Mozambican HTLV-1 sequences had a high inter-strain genetic distance, reflecting in three major clusters. One cluster is associated with the South Africa sequences, one is related with Middle East and India strains and the third is a specific Mozambican cluster. Interestingly, 83.3% of HIV/HTLV-1 co-infection was observed in the Mozambican cluster. The human mtDNA haplotypes revealed that all belong to the African macrohaplogroup L with frequencies representatives of the country. CONCLUSIONS: The Mozambican HTLV-1 genetic diversity detected in this study reveals that although the strains belong to the most prevalent and worldwide distributed Transcontinental subgroup of the Cosmopolitan subtype, there is a high HTLV diversity that could be

  11. Prevalence and risk factors for Human T-Lymphotropic Virus Type 1 (HTLV-1) among maintenance hemodialysis patients.

    Science.gov (United States)

    Santos, Rilma F S; Conceição, Gildásio C; Martins, Márcia S; Kraychete, Angiolina; Penalva, Maria A C; Carvalho, Edgar M; Lopes, Antonio Alberto; Rocha, Paulo Novis

    2017-02-15

    Infection with the human T-cell lymphotropic virus type 1 (HTLV-1), although asymptomatic in most cases, can lead to potentially grave consequences, such as adult T-cell leukemia-lymphoma and HTLV-1-associated myelopathy / tropical spastic paraparesis. Its prevalence varies widely across different populations and geographic regions. A population-based study in the city of Salvador, located in the Northeast region of Brazil, showed an overall prevalence of HTLV-1 seropositivity of 1.7%. Blood borne virus infections are recognized as important hazards for patients and staff in maintenance hemodialysis (MHD) units but most studies focus on hepatitis B, hepatitis C and human immunodeficiency viruses. There are scarce data about HTLV-1 infection in the MHD population. We aimed to determine the prevalence and risk factors for HTLV-1 infection among MHD patients in the city of Salvador-Bahia, Brazil. We conducted a multi-center, cross-sectional study nested in a prospective cohort of MHD patients enrolled from four outpatient clinics. HTLV-1 screening was performed with ELISA and positive cases were confirmed by Western Blot. Factors associated with HTLV-1 seropositivity were identified by multivariable logistic regression. 605 patients were included in the study. The overall prevalence of HTLV-1 infection was 2.48% (15/605), which was similar to that of hepatitis B [1.98% (12/605)] and C [3.14% (19/605)] viruses in our sample. HTLV-1 seropositivity was positively associated with age [prevalence odds ratio (POR) 1.04; 95% confidence interval (CI) 1.01-1.08], unmarried status (POR 3.65; 95% CI 1.13-11.65), and history of blood transfusion (POR 3.35; 95% CI 1.01-11.13). The overall prevalence of HTLV-1 infection in a sample of MHD patients was similar to that of other viral infections, such as hepatitis B and C. Our data revealed that MHD patients who are older, unmarried or who have received blood transfusions are at higher risk for HTLV-1 infection.

  12. Relationship Among Strongyloides stercoralis Infection, Human T-Cell Lymphotropic Virus Type 1 Infection, and Cancer: A 24-Year Cohort Inpatient Study in Okinawa, Japan.

    Science.gov (United States)

    Tanaka, Teruhisa; Hirata, Tetsuo; Parrott, Gretchen; Higashiarakawa, Miwa; Kinjo, Takeshi; Kinjo, Tetsu; Hokama, Akira; Fujita, Jiro

    2016-02-01

    This study evaluated the prevalence of Strongyloides stercoralis infection and human T-cell lymphotropic virus type 1 (HTLV-1) infection in the population. In addition, this study investigated the relationship between S. stercoralis infection or HTLV-1 infection and a patient's risk of developing related cancers. This is a retrospective cohort study of 5,209 patients. The prevalence of S. stercoralis infection was 5.2% among all patients. The prevalence among men (6.3%) was significantly higher than among women (3.6%, P stercoralis and HTLV-1 in the Okinawan population has been steadily decreasing over the past 24 years. HTLV-1 infection significantly increases the odds of developing liver cancer and lymphomas other than ATLL.

  13. Human T-Cell Lymphotropic Virus Types 1 and 2 Seropositivity among Blood Donors at Mbarara Regional Blood Bank, South Western Uganda.

    Science.gov (United States)

    Uchenna Tweteise, Patience; Natukunda, Bernard; Bazira, Joel

    2016-01-01

    Background. The human T-cell lymphotropic virus types 1 and 2 (HTLV 1/2) are retroviruses associated with different pathologies. HTLV-1 causes adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP); HTLV-2 is not clearly associated with a known clinical disease. Both viruses may be transmitted by whole blood transfusion, from mother to child predominantly through breastfeeding, and by sexual contact. Presently, none of the regional blood banks in Uganda perform routine pretransfusion screening for HTLV. The aim of this study was to determine the prevalence of anti-human T-cell lymphotropic virus types 1/2 (HTLV-1/2) antibodies among blood donors at Mbarara Regional Blood Bank in South Western Uganda. A cross-sectional study was conducted between June 2014 and September 2014. Methodology. Consecutive blood samples of 368 blood donors were screened for anti-HTLV-1/2 antibodies using an enzyme linked immunosorbent assay (ELISA). Samples reactive on a first HTLV-1/2 ELISA were further retested in duplicate using the same ELISA. Of the three hundred and sixty-eight blood donors (229 (62.2%) males and 139 (37.8%) females), only two male donors aged 20 and 21 years were HTLV-1/2 seropositive, representing a prevalence of 0.54%. Conclusion. HTLV-1/2 prevalence is low among blood donors at Mbarara Regional Blood Bank. Studies among other categories of people at risk for HTLV 1/2 infection should be carried out.

  14. Human T-Cell Lymphotropic Virus Types 1 and 2 Seropositivity among Blood Donors at Mbarara Regional Blood Bank, South Western Uganda

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    Patience Uchenna Tweteise

    2016-01-01

    Full Text Available Background. The human T-cell lymphotropic virus types 1 and 2 (HTLV 1/2 are retroviruses associated with different pathologies. HTLV-1 causes adult T-cell leukemia/lymphoma (ATL and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP; HTLV-2 is not clearly associated with a known clinical disease. Both viruses may be transmitted by whole blood transfusion, from mother to child predominantly through breastfeeding, and by sexual contact. Presently, none of the regional blood banks in Uganda perform routine pretransfusion screening for HTLV. The aim of this study was to determine the prevalence of anti-human T-cell lymphotropic virus types 1/2 (HTLV-1/2 antibodies among blood donors at Mbarara Regional Blood Bank in South Western Uganda. A cross-sectional study was conducted between June 2014 and September 2014. Methodology. Consecutive blood samples of 368 blood donors were screened for anti-HTLV-1/2 antibodies using an enzyme linked immunosorbent assay (ELISA. Samples reactive on a first HTLV-1/2 ELISA were further retested in duplicate using the same ELISA. Of the three hundred and sixty-eight blood donors (229 (62.2% males and 139 (37.8% females, only two male donors aged 20 and 21 years were HTLV-1/2 seropositive, representing a prevalence of 0.54%. Conclusion. HTLV-1/2 prevalence is low among blood donors at Mbarara Regional Blood Bank. Studies among other categories of people at risk for HTLV 1/2 infection should be carried out.

  15. A Novel Human T-lymphotropic Virus Type 1c Molecular Variant in an Indigenous Individual from New Caledonia, Melanesia

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    Charavay, Françoise; Touzain, Frédéric; Jeannin, Patricia; Grangeon, Jean-Paul; Laumond, Sylvie; Chungue, Eliane; Martin, Paul M. V.; Gessain, Antoine

    2017-01-01

    Background Human T-Lymphotropic Virus type 1 (HTLV-1) is endemic among people of Melanesian descent in Papua New Guinea, Solomon Islands and Vanuatu, and in Indigenous populations from Central Australia. Molecular studies revealed that these Australo-Melanesian strains constitute the highly divergent HTLV-1c subtype. New Caledonia is a French overseas territory located in the Southwest Pacific Ocean. HTLV-1 situation is poorly documented in New Caledonia and the molecular epidemiology of HTLV-1 infection remains unknown. Objectives Studying 500 older adults Melanesian natives from New Caledonia, we aim to evaluate the HTLV-1 seroprevalence and to molecularly characterize HTLV-1 proviral strains. Study design Plasma from 262 men and 238 females (age range: 60–96 years old, mean age: 70.5) were screened for anti-HTLV-1 antibodies by particle agglutination (PA) and indirect immunofluorescence assay (IFA). Serological confirmation was obtained using Western blot assay. DNAs were extracted from peripheral blood buffy coat of HTLV-1 seropositive individuals, and subjected to four series of PCR (LTR-gag; pro-pol; pol-env and tax-LTR). Primers were designed from highly common conserved regions of the major HTLV-1 subtypes to characterize the entire HTLV-1 proviral genome. Results Among 500 samples, 3 were PA and IFA positive. The overall seroprevalence was 0.6%. The DNA sample from 1 New Caledonian woman (NCP201) was found positive by PCR and the complete HTLV-1 proviral genome (9,033-bp) was obtained. The full-length HTLV-1 genomic sequence from a native woman from Vanuatu (EM5), obtained in the frame of our previous studies, was also characterized. Both sequences belonged to the HTLV-1c Australo-Melanesian subtype. The NCP201 strain exhibited 0.3% nucleotide divergence with the EM5 strain from Vanuatu. Furthermore, divergence reached 1.1% to 2.9% with the Solomon and Australian sequences respectively. Phylogenetic analyses on a 522-bp-long fragment of the gp21-env gene

  16. Repression of Human T-lymphotropic virus type 1 Long Terminal Repeat sense transcription by Sp1 recruitment to novel Sp1 binding sites

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    Fauquenoy, Sylvain; Robette, Gwenaëlle; Kula, Anna; Vanhulle, Caroline; Bouchat, Sophie; Delacourt, Nadège; Rodari, Anthony; Marban, Céline; Schwartz, Christian; Burny, Arsène; Rohr, Olivier; Van Driessche, Benoit; Van Lint, Carine

    2017-01-01

    Human T-lymphotropic Virus type 1 (HTLV-1) infection is characterized by viral latency in the majority of infected cells and by the absence of viremia. These features are thought to be due to the repression of viral sense transcription in vivo. Here, our in silico analysis of the HTLV-1 Long Terminal Repeat (LTR) promoter nucleotide sequence revealed, in addition to the four Sp1 binding sites previously identified, the presence of two additional potential Sp1 sites within the R region. We demonstrated that the Sp1 and Sp3 transcription factors bound in vitro to these two sites and compared the binding affinity for Sp1 of all six different HTLV-1 Sp1 sites. By chromatin immunoprecipitation experiments, we showed Sp1 recruitment in vivo to the newly identified Sp1 sites. We demonstrated in the nucleosomal context of an episomal reporter vector that the Sp1 sites interfered with both the sense and antisense LTR promoter activities. Interestingly, the Sp1 sites exhibited together a repressor effect on the LTR sense transcriptional activity but had no effect on the LTR antisense activity. Thus, our results demonstrate the presence of two new functional Sp1 binding sites in the HTLV-1 LTR, which act as negative cis-regulatory elements of sense viral transcription. PMID:28256531

  17. A cluster of human T-cell lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis in Jujuy, Argentina.

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    Biglione, Mirna M; Pizarro, Manuel; Puca, Alberto; Salomón, Horacio E; Berría, Maria I

    2003-04-01

    Compared with other regions in Argentina, greater human T-cell lymphotropic virus type I (HTLV-I) seroprevalence has been reported in Jujuy Province, where it reaches 2.32% in the general population, so that a search for HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) cases deserved to be carried out. Accordingly, a clinically diagnosed and serologically confirmed cluster of cases in 1 man and 10 women, including 2 sisters, is described here. Most patients (9/11) were born in Cochinoca Department, located in an Andes highland area called Puna Jujeña, situated at more that 3400 m above sea level. No history of risk factors was disclosed, except for a single transfusion in 1 patient. In contrast to the Andean region of Bolivia, where high HTLV-I seroprevalence is in part attributable to Japanese immigrants, the Jujuy population mainly consists of aborigines, mestizos, and European descendants. Therefore, the long-term presence of virus in Jujuy natives may be taken for granted. Considering the HAM/TSP cluster described here plus previously reported isolated cases in neighboring Salta Province, we speculate that the Puna Jujeña region and regions in that vicinity would be a microepidemic focus of disease. To determine the role of possible pathogenic cofactors such as geographic, ethnic, genetic, and cultural features, further pertinent surveys are required in subtropical northwestern Argentina.

  18. Insights into origins of Human T-cell Lymphotropic Virus Type 1 based on new strains from aboriginal people of Canada.

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    Andonov, Anton; Coulthart, Michael B; Pérez-Losada, Marcos; Crandall, Keith A; Posada, David; Padmore, Ruth; Giulivi, Antonio; Oger, Joel J; Peters, Andrew A; Dekaban, Gregory A

    2012-12-01

    The causes of the worldwide distribution of Human T-cell Lymphotropic Virus Type 1 (HTLV-1) remain incompletely understood, with competing hypotheses regarding the number and timing of events leading to intercontinental spread on historical and prehistoric timescales. Ongoing discovery of this virus in aboriginal populations of Asia and the Americas has been the main source of evidence for the latter. We conducted molecular phylogenetic and dating analyses for 13 newly reported HTLV-1 strains from Canada. We analyzed two full-length proviral genomes from aboriginal residents of Nunavut (an autonomous territory in Northern Canada including most of the Canadian Arctic), 11 long-terminal-repeat (LTR) sequences from aboriginal residents of British Columbia's Pacific coast, and 2 LTR sequences from non-aboriginal Canadians. Phylogenetic analysis demonstrated a well-supported affinity between the two Nunavut strains and two East Asian strains, suggesting the presence of an Asian-American sublineage within the widespread "transcontinental" subgroup A clade of HTLV-1 Cosmopolitan subtype a. This putative sublineage was estimated to be 5400-11,900 years in age, consistent with a long-term presence of HTLV-1 in aboriginal populations of the Canadian Arctic. Phylogenetic affinities of the other 11 Canadian HTLV-1 aboriginal strains were diverse, strengthening earlier evidence for multiple incursions of this virus into coastal aboriginal populations of British Columbia. Our results are consistent with the hypothesis of ancient presence of HTLV-1 in aboriginal populations of North America. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Two Cases of Human T-Lymphotropic Virus Type I-Associated Myelopathy/Tropical Spastic Paraparesis Caused by Living-Donor Renal Transplantation

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    Yasutaka Tajima

    2016-01-01

    Full Text Available In rare instances, recipients of organ transplants from human T-lymphotropic virus type I- (HTLV-I- positive donors reportedly developed neurologic symptoms due to HTLV-I-associated myelopathy (HAM. We present herein two cases of HAM associated with renal transplantation from HTLV-I seropositive living-donors. The first patient was a 42-year-old woman with chronic renal failure for twelve years and seronegative for HTLV-I. She underwent renal transplantation with her HTLV-I seropositive mother as the donor, and she developed HAM three years after the transplantation. The second patient was a 65-year-old man who had been suffering from diabetic nephropathy. He was seronegative for HTLV-I and underwent renal transplantation one year previously, with his HTLV-I seropositive wife as the donor. He developed HAM eight months after renal transplantation. Both cases showed neurological improvements after the immunomodulating therapies. We tried to shed some light on the understanding of immunological mechanisms of transplantation-associated HAM, focusing on therapeutic strategies based on the immunopathogenesis of the condition.

  20. Use of anti-tumor necrosis factor biologics in the treatment of rheumatoid arthritis does not change human T-lymphotropic virus type 1 markers: a case series.

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    Umekita, Kunihiko; Umeki, Kazumi; Miyauchi, Shunichi; Ueno, Shiro; Kubo, Kazuyoshi; Kusumoto, Norio; Takajo, Ichiro; Nagatomo, Yasuhiro; Okayama, Akihiko

    2015-09-01

    Anti-tumor necrosis factor (anti-TNF) biologics are effective in the treatment of rheumatoid arthritis (RA); however, it is still not clear whether this treatment promotes the development of malignancies such as lymphoma. Human T-lymphotropic virus type 1 (HTLV-1), which is a causative agent of adult T-cell lymphoma (ATL), is prevalent in Japan. Many HTLV-1-positive patients with RA are assumed to exist; however, there have thus far been no reports on the effect of anti-TNF biologics on HTLV-1-positive patients. We analyzed the response to treatment with anti-TNF biologics and change of HTLV-1 markers in two cases of RA. The two cases showed no response based on the European League Against of Rheumatism response criteria 60-96 weeks after administration of anti-TNF biologics (infliximab and etanercept). No signs of ATL were observed and HTLV-1 markers, such as proviral load and clonality of HTLV-1-infected cells, showed no significant change in either of two cases. Therefore, treatment with anti-TNF biologics did not induce activation of HTLV-1, although the effect on RA was not as effective as in HTLV-1-negative patients in this limited study. Further long-term study with a greater number of patients is necessary to clarify the safety and efficacy of anti-TNF biologics in HTLV-1-positive patients with RA.

  1. Endemicity and phylogeny of the human T cell lymphotropic virus type II subtype A from the Kayapo Indians of Brazil: evidence for limited regional dissemination.

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    Switzer, W M; Black, F L; Pieniazek, D; Biggar, R J; Lal, R B; Heneine, W

    1996-05-01

    Long terminal repeat (LTR)-based restriction fragment length polymorphism (RFLP) analysis of human T cell lymphotropic virus type II (HTLV-II) from 17 seropositive Kayapo Indians from Brazil showed that all 17 samples contained a unique HTLV-IIa subtype (A-II). Additional RFLP screening demonstrated the presence of this subtype in two of three Brazilian blood donors and a Mexican prostitute and her child. In contrast, 129 samples from blood donors and intravenous drug users (IDUs) from the United States, two Pueblo Indian samples, five samples from Norwegian IDUs, and two samples from blood donors from Denmark were all found to be a different HTLV-IIa subtype (A-III). Phylogenetic analysis of two Kayapo and one Mexican LTR sequences showed that they cluster with a subtype A-II sequence from a Brazilian blood donor and with sequences from two prostitutes from Ghana and Cameroon. These results demonstrate that infection with the A-II subtype is endemic among the Kayapo Amerindians, has disseminated to non-Indian populations in Brazil, and is also present in Mexico. Furthermore, the A-II subtype does not appear to represent an origin for the HTLV-IIa infection in urban areas of the United States and Europe. This study provides evidence that HTLV-IIa may be a Paleo-Indian subtype as previously suggested for HTLV-IIb.

  2. Mapping the molecular characteristics of Brazilian human T-cell lymphotropic virus type 1 Env (gp46 and Pol amino acid sequences for vaccine design

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    Aline Cristina Mota-Miranda

    2007-09-01

    Full Text Available This study was carried out to evaluate the molecular pattern of all available Brazilian human T-cell lymphotropic virus type 1 Env (n = 15 and Pol (n = 43 nucleotide sequences via epitope prediction, physico-chemical analysis, and protein potential sites identification, giving support to the Brazilian AIDS vaccine program. In 12 previously described peptides of the Env sequences we found 12 epitopes, while in 4 peptides of the Pol sequences we found 4 epitopes. The total variation on the amino acid composition was 9 and 17% for human leukocyte antigen (HLA class I and class II Env epitopes, respectively. After analyzing the Pol sequences, results revealed a total amino acid variation of 0.75% for HLA-I and HLA-II epitopes. In 5 of the 12 Env epitopes the physico-chemical analysis demonstrated that the mutations magnified the antigenicity profile. The potential protein domain analysis of Env sequences showed the loss of a CK-2 phosphorylation site caused by D197N mutation in one epitope, and a N-glycosylation site caused by S246Y and V247I mutations in another epitope. Besides, the analysis of selection pressure have found 8 positive selected sites (w = 9.59 using the codon-based substitution models and maximum-likelihood methods. These studies underscore the importance of this Env region for the virus fitness, for the host immune response and, therefore, for the development of vaccine candidates.

  3. Western blot seroindeterminate individuals for Human T-lymphotropic Virus 1/2 (HTLV-1/2 in Fortaleza (Brazil: a serological and molecular diagnostic and epidemiological approach

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    Terezinha de Jesus Teixeira Santos

    2003-06-01

    Full Text Available How to handle Western blot (WB seroindeterminate individuals for Human T-lymphotropic Virus 1/2 (HTLV-1/2 constitutes a challenge for blood banks and fam ilies. We made a cross-sectional study of 191 enzyme linked immunoassay (EIA reactive individuals from the hematological center (HEMOCE of Fortaleza (Brazil, examining their serological (WB and molecular (PCR diagnosis, and demographic profiles, as well as a possible association of their condition with other infectious pathologies and risk factors. Ethical institutional approval and personal consent were obtained. Out of 191 EIA reactive individuals, 118 were WB seroindeterminate and 73 were seropositive for HTLV-1/2. In the PCR analysis of 41 WB seroindeterminate individuals, 9 (22% were positive and 32 (78% were negative for HTLV-1/2. The demographic analysis indicated a trend towards a predominance of males among the seroindeterminate individuals and females in the seropositive ones. The seroindeterminate individuals were younger than the seropositive ones. We did not find any association of these conditions with syphilis, Chagas disease or HIV or hepatitis, and with risk factors such as breast-feeding, blood transfusion, STD (syphilis and IDU.

  4. Human T-lymphotropic virus-1/2 detected in drug abused men who have sex with men in Surakarta Indonesia

    Science.gov (United States)

    Prasetyo, Afiono Agung; Sari, Yulia

    2017-02-01

    Human T-cell lymphotropic virus types 1 and 2 (HTLV-1/2) are retroviruses that probably among the most neglected blood-borne pathogens. The molecular epidemiology data of HTLV-1/2 in Indonesia is very rare. This study evaluated the prevalence of HTLV-1 and 2 in men who have sex with men with drug abused history in Surakarta Indonesia, to track the presentation of HTLV-1/2 in Indonesia. All blood samples collected from men who have sex with men with drug abused history in Surakarta in 2009-2013 were tested using enzyme linked immunosorbent assays and confirmed by RT-PCR nested addressed the part of HTLV-1 LTR and HTLV-2 LTR region, respectively. The specificity of the molecular assays was confirmed by sequencing the amplicons. The anti HTLV-1/2 positive rate was 4.8% (6/126). All positive serological samples were confirmed by nested RT-PCR. Of these, two was HTLV-1 positive and four was HTLV-2 positive. Molecular analysis of positive PCR products revealed that all HTLV-1 isolate had close relationship with HTLV-1 isolated in Japan while all HTLV-2 isolate with that of isolated in USA. HTLV-1 and HTLV-2 were detected in men who have sex with men with drug abused history in Surakarta indicated that these viruses were circulated in Indonesia, especially in the high risk communities

  5. Adult T-cell leukemia/lymphoma in a Peruvian hospital in human T-lymphotropic virus type 1 (HTLV-1) positive patients.

    Science.gov (United States)

    Rodríguez-Zúñiga, Milton José Max; Cortez-Franco, Florencio; Qujiano-Gomero, Eberth

    2017-05-01

    Adult T-cell leukemia/lymphoma (ATLL) is an aggressive neoplasm of T-lymphocytes associated with human T-lymphotropic virus type I (HTLV-1) infection. As HTLV-1 is endemic in native ethnics in South America, and its infection leads to several chronic diseases as ATLL with poor prognosis, we aimed to present three ATLL cases and to review current literature. Two cases were from the mountains of Peru, while one was from an endemic harbor of the country. An acute ATLL patient presented with multipapular infiltration of the skin and died 2 weeks after admission because of septic shock. The two chronic ATLL patients presented with erythematous plaques and erythroderma. They had swollen lymph nodes, lymphocytosis, and atypical lymphocytes on blood smear, with normal biochemical results. They both passed away a few months after diagnosis. ATLL is developed after years of HTLV-1 carrier status; therefore, physicians should know the principal clinical and laboratory findings in order to make prompt diagnosis. Prognosis is still poor in aggressive and indolent variants, with survival rates from months to a few years. Treatment based on chemotherapy, antiretroviral, and allogeneic stem cell transplantation are improving survival rates but with limited results. © 2017 The International Society of Dermatology.

  6. Expansion of Natural Killer Cells in Peripheral Blood in a Japanese Elderly with Human T-Cell Lymphotropic Virus Type 1-Related Skin Lesions

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    Shinsaku Imashuku

    2014-01-01

    Full Text Available Natural killer (NK cells were proposed to play an important role in the pathogenesis of human T-cell lymphotropic virus type 1- (HTLV-1- associated neurologic disease. Our patient was a 77-year-old Japanese man, who had been treated for infective dermatitis associated with HTLV-1 for nearly 10 years. When referred to us, he had facial eczema/edema as well as extensive dermatitis at the neck/upper chest and nuchal area/upper back regions. Dermal lesions had CD3+CD4+ cells, but no NK cells. Flow cytometry of his peripheral blood showed a phenotype of CD2+ (97%, CD3+ (17%, CD4+ (12%, CD7+ (94%, CD8+ (6%, CD11c+ (70%, CD16+ (82%, CD19+ (0%, CD20+ (0%, CD56+ (67%, HLA-DR+ (68%, and NKp46+ (36%. Absolute numbers of CD56+NK cells in the peripheral blood were in a range of 986/μL–1,270/μL. The expanded NK cells in the peripheral blood are considered to be reactive, to maintain the confinement of the HTLV-1-positive CD4+ cells in the skin, and to prevent the progression of the disease.

  7. Seroprevalence of Human T-Cell Lymphotropic Virus-1/2 in Blood Donors in Northern Pakistan: Implications for Blood Donor Screening.

    Science.gov (United States)

    Niazi, Saifullah Khan; Bhatti, Farhat Abbas; Salamat, Nuzhat

    2015-12-01

    To determine the seroprevalence of Human T-cell Lymphotropic Virus-1/2 (HTLV-1/2) in blood donors in Northern Pakistan. Descriptive study. Armed Forces Institute of Transfusion, Rawalpindi, from July to August 2013. A total of 2100 blood donors were screened for anti-HTLV-1/2 antibodies during the study period, in a pool of six, on a highly sensitive, Chemiluminiscent Microparticle Immunoassay (CMIA) based system. The screening test-reactive donors were recalled, counseled and interviewed, and a fresh sample was obtained for confirmatory testing. Confirmation was performed using additional immunoassays including Line Immunoassay (LIA); with additional testing for HTLV-1 pvDNAPCR. Frequency and percentages were determined. Four donors (0.19%) were repeatedly screening test-reactive and were subsequently confirmed to be HTLV-1 infected by line immunoassay and HTLV-1 pvDNAPCR. All four donors were male with mean age of 27 ± 6.27 years. Two (50%) of the positive donors gave history of Multiple Sexual Partners (MSP). HTLV-1 seroprevalence in Northern Pakistan blood donors was determined to be 0.19%. Large scale studies, including the cost effectiveness of screening blood donations for anti-HTLV-1/2 in Pakistan, are recommended.

  8. [The lymphotropic marking and biopsy of sentinel lymph nodes in T1 tumors--a new approach to the staging of axillary lymphatic metastasis in breast cancer].

    Science.gov (United States)

    Deliĭski, T; Baĭchev, G; Popovska, S; Penkova, R

    1997-01-01

    It is the purpose of the study to assay the possibility of demonstrating axillary lymph status through marking and biopsy of sentinel lymph nodes. Preoperative lymphotropic marking of sentinel lymph nodes is performed in 48 female patients presenting mammary gland carcinoma, measuring up to two centimeters. Drimaren 0.5 ml (in 18 cases), Mitoxantrone (17 cases) or Patent Blue (13 cases) each are perineoplastically injected in two points. Intraoperatively, in 34 patients blue stained lymph nodes (from Patent Blue and Mitoxantrone mainly) are identified, and compared with the results of axillary dissection. Metastases in sentinel nodes are documented in seven instances. In the remainder (30) which are histologically negative, lymph node metastasis II level is discovered in one case (false negative = 3.3 per cent). As shown by the initial observations perioperative marking of lymph nodes with Patent Blue and Mitoxantrone contribute to demonstrate sentinel nodes, and by biopsy study of the latter it is possible to judge about the pattern of lymph metastasizing of mammary gland carcinoma.

  9. Low prevalence of human immunodeficiency virus-1 (HIV-1), HIV-2, and human T cell lymphotropic virus-1 infection in Somalia.

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    Scott, D A; Corwin, A L; Constantine, N T; Omar, M A; Guled, A; Yusef, M; Roberts, C R; Watts, D M

    1991-12-01

    A seroepidemiologic survey was conducted to determine the prevalence of human immunodeficiency virus type 1 (HIV-1), HIV-2, human T cell lymphotropic virus type I (HTLV-I), and Treponema pallidum infection among southern Somalis. Sera were collected from 1,269 study subjects in the urban area of the capital city, Mogadishu, and in the rural towns of Merka, Qoryoley, and Kismayo. The subjects included 57 prostitutes, 79 sexually transmitted disease (STD) patients, and 1,133 others, including outpatient and hospitalized patients with leprosy, tuberculosis, other infectious diseases, individuals from rehabilitation camps and secondary schools, and Ethiopian immigrants. Results indicated that none of the sera were positive for HIV-1 and HIV-2 by Western blot, but one was positive for HTLV-I. The prostitutes had a significantly higher prevalence of treponemal antibody (50.8%; P less than 0.0001) than either the STD patients (12.6%) or the other subjects (5.2%). Epidemiologic data indicated that 94% of the males and females were circumcised and only 2.6% of the males used condoms. Overall, the results of this study suggested a very low prevalence of HIV-1, HIV-2, and HTLV-I infections, especially among prostitutes and STD patients, who were considered at greatest risk of contracting these retroviral infections.

  10. Low Proviral Load is Associated with Indeterminate Western Blot Patterns in Human T-Cell Lymphotropic Virus Type 1 Infected Individuals: Could Punctual Mutations be Related?

    Science.gov (United States)

    Cánepa, Camila; Salido, Jimena; Ruggieri, Matías; Fraile, Sindy; Pataccini, Gabriela; Berini, Carolina; Biglione, Mirna

    2015-10-28

    indeterminate Western blot (WB) patterns are a major concern for diagnosis of human T-cell lymphotropic virus type 1 (HTLV-1) infection, even in non-endemic areas. (a) to define the prevalence of indeterminate WB among different populations from Argentina; (b) to evaluate if low proviral load (PVL) is associated with indeterminate WB profiles; and (c) to describe mutations in LTR and tax sequence of these cases. Among 2031 samples, 294 were reactive by screening. Of them, 48 (16.3%) were WB indeterminate and of those 15 (31.3%) were PCR+. Quantitative real-time PCR (qPCR) was performed to 52 HTLV-1+ samples, classified as Group 1 (G1): 25 WB+ samples from individuals with pathologies; Group 2 (G2): 18 WB+ samples from asymptomatic carriers (AC); and Group 3 (G3): 9 seroindeterminate samples from AC. Median PVL was 4.78, 2.38, and 0.15 HTLV-1 copies/100 PBMCs, respectively; a significant difference (p=0.003) was observed. Age and sex were associated with PVL in G1 and G2, respectively. Mutations in the distal and central regions of Tax Responsive Elements (TRE) 1 and 2 of G3 were observed, though not associated with PVL.The 8403A>G mutation of the distal region, previously related to high PVL, was absent in G3 but present in 50% of WB+ samples (p = 0.03). indeterminate WB results confirmed later as HTLV-1 positive may be associated with low PVL levels. Mutations in LTR and tax are described; their functional relevance remains to be determined.

  11. Human T-Lymphotropic Virus Type I (HTLV-1) Infection among Iranian Blood Donors: First Case-Control Study on the Risk Factors.

    Science.gov (United States)

    Hedayati-Moghaddam, Mohammad Reza; Tehranian, Farahnaz; Bayati, Maryam

    2015-11-04

    Human T-cell lymphotropic virus type 1 (HTLV-1) infection is an endemic condition in Northeast Iran and, as such, identification of risk factors associated with the infection in this region seems to be a necessity. All the possible risk factors for HTLV-1 seropositivity among first-time blood donors were evaluated in Mashhad, Iran, during the period of 2011-2012. Blood donation volunteers were interviewed for demographic data, medical history, and behavioral characteristics and the frequencies of risk factors were compared between HTLV-1 positive (case) and HTLV-1 negative (control) donors. The data was analyzed using Chi square and t-tests. Logistic regression analysis was performed to identify independent risk factors for the infection. Assessments were carried out on 246 cases aged 17-60 and 776 controls aged 17-59, who were matched based on their ages, gender, and date and center of donation. Logistic analysis showed low income (OR = 1.53, p = 0.035), low educational level (OR = 1.64, p = 0.049), being born in the cities of either Mashhad (OR = 2.47, p = 0.001) or Neyshabour (OR = 4.30, p risk factors for HTLV-1 infection, such as prolonged breastfeeding and sexual promiscuity. Pre-donation screening of possible risk factors for transfusion-transmissible infections should also be considered as an important issue, however, a revision of the screening criteria such as a history of transfusion for more than one year prior to donation is strongly recommended.

  12. Prevalence of human retroviral infection in Quillabamba and Cuzco, Peru: a new endemic area for human T cell lymphotropic virus type 1.

    Science.gov (United States)

    Zurita, S; Costa, C; Watts, D; Indacochea, S; Campos, P; Sanchez, J; Gotuzzo, E

    1997-05-01

    An epidemiologic study was conducted to determine the prevalence of retroviral infections among people of Qucchua origin in Cuzco and Quillabamba, Peru. The study volunteers included individuals at low and at high risk for retroviral infections. Each volunteer was interviewed to obtain clinical and epidemiologic data, and to identify risk behaviors for infection. The serum was tested for human immunodeficiency virus type 1 (HIV-1) and human T cell lymphotropic virus types 1/2 (HTLV-1/2) by standard enzyme-linked immunosorbent and Western blot assays. Among a total of 370 volunteers enrolled in the study, 276 were women and 94 were men whose ages ranged between 15 and 49 years. Infection with HTLV-1 was demonstrated in 5.1% (19 of 370), and one of these, a homosexual, was also positive for HIV-1; none had HTLV-2. Overall, the rate of HTLV-1 infection was 5.3% (5 of 94) for males and 5% (14 of 276) for females. Among the low risk group of 211 healthy pregnant women, five (2.3%) were positive for HTLV-1. The rate of HTLV-1 infection in this group was significantly correlated with a history of dental surgery, as well as other surgical procedures, and a history of jaundice. Among the volunteers who practiced risk behavior(s) for retroviral infections, the positive rates for HTLV-1 were 13.7% (7 of 51) for female sex workers, 6.2% (3 of 48) for homosexuals and/or bisexuals, 8.5% (4 of 47) for patients with sexually transmitted diseases (STDs), and 0.0% (0 of 13) for promiscuous heterosexual males. In female sex workers. HTLV-1 infection was found to be significantly associated with age, a history of STDs or genital ulcers, sexual intercourse during menses, and vaginal douching (P < 0.05). A low prevalence of HIV-1 infection indicates that the virus has not yet spread significantly in these areas.

  13. Distinct transformation tropism exhibited by human T lymphotropic virus type 1 (HTLV-1) and HTLV-2 is the result of postinfection T cell clonal expansion.

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    Kannian, Priya; Yin, Han; Doueiri, Rami; Lairmore, Michael D; Fernandez, Soledad; Green, Patrick L

    2012-04-01

    Human T lymphotropic virus type 1 (HTLV-1) and HTLV-2 are related but pathogenically distinct viruses. HTLV-1 mainly causes adult T cell leukemia, while HTLV-2 is not associated with leukemia. In vitro, HTLV-1 and HTLV-2 predominantly transform CD4(+) and CD8(+) T cells, respectively: the genetic determinant maps to the viral envelope. Herein, we investigate whether this transformation tropism occurs during initial infection or subsequently during the cellular transformation process. Since most individuals are chronically infected at the time of detection, we utilized an established rabbit model to longitudinally measure the early HTLV-1 and HTLV-2 infection and replication kinetics in purified CD4(+) and CD8(+) T cells. HTLV-1 and HTLV-2 were detected in both CD4(+) and CD8(+) T cells within 1 week postinoculation. In HTLV-1-infected rabbit CD4(+) T cells, proviral burden and tax/rex mRNA expression peaked early, and expression levels were directly proportional to each other. The late expression of the antisense transcript (Hbz or Aph-2) correlated directly with a late proviral burden peak in HTLV-1- or HTLV-2-infected rabbit CD8(+) T cells, respectively. This study provides the first in vivo evidence that these viruses do not exhibit cellular preference during initial infection. We further evaluated the transformation tropism of HTLV-1 and HTLV-2 over a 9-week period using in vitro cell growth/immortalization assays. At the early weeks, both HTLV-1 and HTLV-2 showed proportionate growth of CD4(+) and CD8(+) T cells. However, beyond week 5, the predominance of one particular T cell type emerged, supporting the conclusion that transformation tropism is a postinfection event due to selective clonal expansion over time.

  14. Human T-Lymphotropic Virus Type 1 and 2 Seroprevalence among first-time blood donors in Chile, 2011-2013.

    Science.gov (United States)

    San Martín, Héctor; Balanda, Monserrat; Vergara, Nicolás; Valenzuela, María Antonieta; Cartier, Luis; Ayala, Salvador; Ramírez, Eugenio

    2016-06-01

    Infection with human T-lymphotropic virus type 1/2 (HTLV-1/2) is a major health problem. HTLV-1/2 infection is endemic in Chile but representative donor prevalence data are lacking. Data on all blood donors in a large network of Chilean blood centers were examined during 2011-2013. Screening of HTLV-1/2 antibodies were measured by enzyme immunoassay (EIA) at all blood banks. Blood samples with anticoagulants from initially reactive blood donors were analyzed by serological confirmation tests (immunofluorescence or recombinant immunoblot) at the HTLV National Reference Laboratory of the Public Health Institute of Chile. Additionally, detection of HTLV-1 and HTLV-2 provirus in peripheral blood mononuclear cells (PBMCs) was performed in all blood donors as confirmatory test. Prevalence rates were calculated. Among 694,016 donors, 706 were seropositive for HTLV-1 (prevalence, 1.02 cases per 1,000; 95% confidence interval [CI], 0.94-1.09), and 97 were seropositive for HTLV-2 (prevalence, 0.14 cases per 1,000; 95%CI, 0.11-0.17). Prevalence of HTLV-1 differed considerably by region, from 0.51 to 1.69 per 1,000. Prevalence of HTLV-2 was similar across the country (0.12-0.16). HTLV-1 prevalence was associated with female sex, older age, and residence in the north of Chile. HTVL-2 prevalence was associated with older age. The HTLV-1 prevalence among Chilean blood donors was relatively high and could be reduced by improving donor recruitment and selection in high prevalence areas. Blood center data may contribute to surveillance for HTLV-1 and HTLV-2 infections.

  15. Polymorphism in the promoter region of the mannose-binding lectin gene among human T-cell lymphotropic virus infected subjects

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    AEM Alves

    2007-12-01

    Full Text Available The present study investigated the frequency of the mutations at positions -550 and -221 of the mannose-binding lectin (MBL gene in a sample of 75 human T-cell lymphotropic virus (HTLV infected patients and 96 HTLV seronegative controls, in order to evaluate the occurrence of a possible association between the polymorphism and HTLV infection. A sequence specific primer-polymerase chain reaction was used for discrimination of the polymorphism. The analysis of allele frequencies at position -550 did not show any significant differences between HTLV infected group and controls, but there was a significant difference at position -221. The comparative analysis of haplotypes frequencies were not significant, but the genotype frequencies between the two groups, revealed a higher prevalence of genotype LYLX (25.3%, associated with medium and low MBL serum levels among HTLV infected subjects. The odds ratio estimation demonstrated that the presence of genotype LYLX was associated with an increased risk of HTLV infection (p = 0.0096; 1.38 < IC95% < 7.7605. There was no association between proviral load and the promoter polymorphism, but when promoter and exon 1 mutations were matched, it was possible to identify a significant higher proviral load among HTLV infected individuals carrying haplotypes correlated to low serum levels of MBL. The present study shows that the polymorphism in the promoter region of the MBL gene may be a genetic marker associated with HTLV infection, and emphasizes the need for further studies to determinate if the present polymorphism have any impact on diseases linked to HTLV infection.

  16. Identification of TL-Om1, an adult T-cell leukemia (ATL) cell line, as reference material for quantitative PCR for human T-lymphotropic virus 1.

    Science.gov (United States)

    Kuramitsu, Madoka; Okuma, Kazu; Yamagishi, Makoto; Yamochi, Tadanori; Firouzi, Sanaz; Momose, Haruka; Mizukami, Takuo; Takizawa, Kazuya; Araki, Kumiko; Sugamura, Kazuo; Yamaguchi, Kazunari; Watanabe, Toshiki; Hamaguchi, Isao

    2015-02-01

    Quantitative PCR (qPCR) for human T-lymphotropic virus 1 (HTLV-1) is useful for measuring the amount of integrated HTLV-1 proviral DNA in peripheral blood mononuclear cells. Many laboratories in Japan have developed different HTLV-1 qPCR methods. However, when six independent laboratories analyzed the proviral load of the same samples, there was a 5-fold difference in their results. To standardize HTLV-1 qPCR, preparation of a well-defined reference material is needed. We analyzed the integrated HTLV-1 genome and the internal control (IC) genes of TL-Om1, a cell line derived from adult T-cell leukemia, to confirm its suitability as a reference material for HTLV-1 qPCR. Fluorescent in situ hybridization (FISH) showed that HTLV-1 provirus was monoclonally integrated in chromosome 1 at the site of 1p13 in the TL-Om1 genome. HTLV-1 proviral genome was not transferred from TL-Om1 to an uninfected T-cell line, suggesting that the HTLV-1 proviral copy number in TL-Om1 cells is stable. To determine the copy number of HTLV-1 provirus and IC genes in TL-Om1 cells, we used FISH, digital PCR, and qPCR. HTLV-1 copy numbers obtained by these three methods were similar, suggesting that their results were accurate. Also, the ratio of the copy number of HTLV-1 provirus to one of the IC genes, RNase P, was consistent for all three methods. These findings indicate that TL-Om1 cells are an appropriate reference material for HTLV-1 qPCR. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  17. Human T-Lymphotropic Virus Type 1 (HTLV-1 and Regulatory T Cells in HTLV-1-Associated Neuroinflammatory Disease

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    Yoshihisa Yamano

    2011-08-01

    Full Text Available Human T-lymphotropic virus type 1 (HTLV-1 is a retrovirus that is the causative agent of adult T cell leukemia/lymphoma (ATL and associated with multiorgan inflammatory disorders, including HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP and uveitis. HTLV-1-infected T cells have been hypothesized to contribute to the development of these disorders, although the precise mechanisms are not well understood. HTLV-1 primarily infects CD4+ T helper (Th cells that play a central role in adaptive immune responses. Based on their functions, patterns of cytokine secretion, and expression of specific transcription factors and chemokine receptors, Th cells that are differentiated from naïve CD4+ T cells are classified into four major lineages: Th1, Th2, Th17, and T regulatory (Treg cells. The CD4+CD25+CCR4+ T cell population, which consists primarily of suppressive T cell subsets, such as the Treg and Th2 subsets in healthy individuals, is the predominant viral reservoir of HTLV-1 in both ATL and HAM/TSP patients. Interestingly, CD4+CD25+CCR4+ T cells become Th1-like cells in HAM/TSP patients, as evidenced by their overproduction of IFN-γ, suggesting that HTLV-1 may intracellularly induce T cell plasticity from Treg to IFN-γ+ T cells. This review examines the recent research into the association between HTLV-1 and Treg cells that has greatly enhanced understanding of the pathogenic mechanisms underlying immune dysregulation in HTLV-1-associated neuroinflammatory disease.

  18. Low Proviral Load is Associated with Indeterminate Western Blot Patterns in Human T-Cell Lymphotropic Virus Type 1 Infected Individuals: Could Punctual Mutations be Related?

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    Camila Cánepa

    2015-10-01

    Full Text Available Background: indeterminate Western blot (WB patterns are a major concern for diagnosis of human T-cell lymphotropic virus type 1 (HTLV-1 infection, even in non-endemic areas. Objectives: (a to define the prevalence of indeterminate WB among different populations from Argentina; (b to evaluate if low proviral load (PVL is associated with indeterminate WB profiles; and (c to describe mutations in LTR and tax sequence of these cases. Results: Among 2031 samples, 294 were reactive by screening. Of them, 48 (16.3% were WB indeterminate and of those 15 (31.3% were PCR+. Quantitative real-time PCR (qPCR was performed to 52 HTLV-1+ samples, classified as Group 1 (G1: 25 WB+ samples from individuals with pathologies; Group 2 (G2: 18 WB+ samples from asymptomatic carriers (AC; and Group 3 (G3: 9 seroindeterminate samples from AC. Median PVL was 4.78, 2.38, and 0.15 HTLV-1 copies/100 PBMCs, respectively; a significant difference (p=0.003 was observed. Age and sex were associated with PVL in G1 and G2, respectively. Mutations in the distal and central regions of Tax Responsive Elements (TRE 1 and 2 of G3 were observed, though not associated with PVL.The 8403A>G mutation of the distal region, previously related to high PVL, was absent in G3 but present in 50% of WB+ samples (p = 0.03. Conclusions: indeterminateWBresults confirmed later as HTLV-1 positive may be associated with low PVL levels. Mutations in LTR and tax are described; their functional relevance remains to be determined.

  19. Undifferentiated Pleomorphic Sarcoma and the Importance of Considering the Oncogenic and Immune-Suppressant Role of the Human T-Cell Lymphotropic Virus Type 1: A Case Report

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    Sergio Lupo

    2017-05-01

    Full Text Available IntroductionSoft-tissue sarcomas account for 0.7% of all malignant tumors, with an incidence rate of 3 per 100,000 persons/year. The undifferentiated pleomorphic sarcoma (UPS with giant cells, a high grade tumor of soft tissue, is very unusual, especially in young adults before the age of 40. Human T-cell lymphotropic virus type 1 (HTLV-1 is a human retrovirus, classified as group 1 human carcinogens by The International Agency for Research on Cancer, that causes an aggressive malignancy known as adult T-cell lymphoma/leukemia and a progressive chronic inflammatory neurological disease named HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP. HTLV-1 causes accumulation of genetic mutations in the host genome that could contribute to cellular transformation, one of the oncogenic features of HTLV-1.Case reportWe describe a case of a young woman with UPS who suffered from HAM/TSP with 3 years of evolution. In 2013, the patient started with neurological symptoms: weakness in the legs and bladder dysfunction. One year later, the patient developed a mild paraparesis in both extremities, anti-HTLV-1 antibodies were detected in plasma and in cerebrospinal fluid, and HAM/TSP was confirmed. In November 2015, a benign ganglion cyst was first suspected without intervention and by March 2016 a sarcoma was diagnosed. Three weeks after surgical resection, the tumor aroused in deep tissue and behaved aggressively, implicating a curative wide resection of the fibula, joint reconstruction, and soft-tissue graft. Histopathological examination confirmed UPS with giant cells.Concluding remarksThe unapparent subclinical immunodeficiency state due to HTLV-1 infection deserves to be considered in order to carefully monitor the possibility of developing any type of cancer. Besides, reaching an accurate and timely diagnosis of UPS can be challenging due to the difficulty in diagnosis/classification and delayed consultation. In this particular case

  20. Human T-cell lymphotropic virus type 1 provirus and phylogenetic analysis in patients with mycosis fungoides and their family relatives.

    Science.gov (United States)

    Shohat, M; Shohat, B; Mimouni, D; Pauli, G; Ellerbrok, H; David, M; Hodak, E

    2006-08-01

    Mycosis fungoides (MF) is a cutaneous T-cell lymphoma of unknown aetiology. A pathogenic role of human T-cell lymphotropic virus type 1 (HTLV-1) has been suggested but remains controversial. To determine whether MF is linked to HTLV-1. Blood samples were collected from 60 patients, 15 family relatives of patients with MF (MFRs), 20 healthy controls and 10 patients with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The presence of HTLV-1 antibodies in serum was tested by the Western blot rp21e-enhanced test. DNA was extracted from the blood with the Qiagen blood kit. We used 500 ng of DNA either in conventional HTLV-1-specific polymerase chain reaction (PCR) or in real-time PCR using primers sk43 and sk44 together with a tax-specific fluorescent probe. In Western blot, antibodies against three to four HTLV-1 antigens were detected in 52% of patients with MF. All of the patients with HAM/TSP were positive, while only 7% of the MFRs and none of the 20 healthy controls reacted with HTLV-1 antigens in Western blot. One of 60 patients with MF and one of 15 MFRs were positive in HTLV-1 PCR. These two PCR-positive samples which were quantified in real-time PCR showed that fewer than five in 10(6) cells were HTLV-1 infected. We succeeded in amplifying and sequencing the 5' end of the provirus from the blood of the PCR-positive MFR by seminested PCR. A positive result was also obtained in this test. Phylogenetic tree analyses revealed a high homology of this sequence with other HTLV-1 sequences from the Middle East. The above PCR-positive MFR was the brother of a PCR-negative patient with MF. These findings demonstrate that HTLV-1 is probably not the aetiological agent of MF. However, it may play a role in immunosuppression and in the spreading of the disease.

  1. Prevalence of Human T-lymphotropic virus type 1 (HTLV-1) Infection in Patients with Hematologic Disorders and Non-Hematologic Malignancies in a Tertiary Referral Hospital.

    Science.gov (United States)

    Jalaeikhoo, Hasan; Soleymani, Mosayeb; Rajaeinejad, Mohsen; Keyhani, Manoutchehr

    2017-04-01

    Human T-lymphotropic virus type 1 (HTLV-1) was the first retrovirus identified in human. The current evidence is quite scarce regarding the potential role of HTLV-1 in pathogenesis of hematologic disorders and non-hematologic malignancies. The aim of this study is to evaluate the prevalence of HTLV-1 infection in patients with hematologic disorders and non-hematologic malignancies. This cross-sectional study was conducted on 505 cases of definite diagnosis of hematologic disorders including malignancies as well as non-malignant disorders such as polycythemia and myelofibrosis and non-hematologic malignancies referred to the hematology and medical oncology ward at Army Hospital 501 from January 2015 to January 2016. A 3-mL blood specimen was collected from each patient and tested for the presence of anti-HTLV-1 antibodies using enzyme-linked immunosorbent assay (ELISA). Data were analyzed using SPSS software package version 19 (IBM, New York, USA). Data are presented as mean ± SD if normally distributed and otherwise as median (range). Totally, 242 (48%) males and 263 (52%) females with a mean ± SD age of 52.09 ± 16.24 were enrolled in this study. In total, there were 9 (1.78%) cases positive for HTLV-1 infection including 4 males and 5 females. Seven out of 287 (2.4%) patients with hematologic disorders were infected by HTLV-1. In non-hematologic malignancies, 2 out of 211 cases were positive (0.9%). There was no HTLV-1 positive case in 7 patients with both hematologic and non-hematologic disorders. The difference in HTLV-1 infection prevalence between patients with hematologic disorders and non-hematologic malignancies was not statistically significant different (P = 0.31). There was no association between sex and transfusion history with HTLV-1 infection in this population (P = 0.9 and 0.7, respectively). Our study revealed that the prevalence of HTLV-1 in hematologic disorders is higher than the general population. Further larger prospective studies are

  2. Human T-lymphotropic virus type-1 p30 alters cell cycle G2 regulation of T lymphocytes to enhance cell survival

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    Silverman Lee

    2007-07-01

    Full Text Available Abstract Background Human T-lymphotropic virus type-1 (HTLV-1 causes adult T-cell leukemia/lymphoma and is linked to a number of lymphocyte-mediated disorders. HTLV-1 contains both regulatory and accessory genes in four pX open reading frames. pX ORF-II encodes two proteins, p13 and p30, whose roles are still being defined in the virus life cycle and in HTLV-1 virus-host cell interactions. Proviral clones of HTLV-1 with pX ORF-II mutations diminish the ability of the virus to maintain viral loads in vivo. p30 expressed exogenously differentially modulates CREB and Tax-responsive element-mediated transcription through its interaction with CREB-binding protein/p300 and while acting as a repressor of many genes including Tax, in part by blocking tax/rex RNA nuclear export, selectively enhances key gene pathways involved in T-cell signaling/activation. Results Herein, we analyzed the role of p30 in cell cycle regulation. Jurkat T-cells transduced with a p30 expressing lentivirus vector accumulated in the G2-M phase of cell cycle. We then analyzed key proteins involved in G2-M checkpoint activation. p30 expression in Jurkat T-cells resulted in an increase in phosphorylation at serine 216 of nuclear cell division cycle 25C (Cdc25C, had enhanced checkpoint kinase 1 (Chk1 serine 345 phosphorylation, reduced expression of polo-like kinase 1 (PLK1, diminished phosphorylation of PLK1 at tyrosine 210 and reduced phosphorylation of Cdc25C at serine 198. Finally, primary human lymphocyte derived cell lines immortalized by a HTLV-1 proviral clone defective in p30 expression were more susceptible to camptothecin induced apoptosis. Collectively these data are consistent with a cell survival role of p30 against genotoxic insults to HTLV-1 infected lymphocytes. Conclusion Collectively, our data are the first to indicate that HTLV-1 p30 expression results in activation of the G2-M cell cycle checkpoint, events that would promote early viral spread and T

  3. Superhydrophobic/superoleophilic magnetic elastomers by laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Milionis, Athanasios, E-mail: am2vy@virginia.edu [Smart Materials-Nanophysics, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy); Fragouli, Despina; Brandi, Fernando; Liakos, Ioannis; Barroso, Suset [Smart Materials-Nanophysics, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy); Ruffilli, Roberta [Nanochemistry, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy); Athanassiou, Athanassia, E-mail: athanassia.athanassiou@iit.it [Smart Materials-Nanophysics, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genova (Italy)

    2015-10-01

    Highlights: • We report the development of magnetic nanocomposite sheets. • Laser irradiation of the nanocomposites induces chemical and structural changes to the surface. • The laser-patterned surfaces exhibit superhydrophobicity and superoleophilicity. • The particle contribution in altering the surface and bulk properties of the material is studied. - Abstract: We report the development of magnetic nanocomposite sheets with superhydrophobic and supeoleophilic surfaces generated by laser ablation. Polydimethylsiloxane elastomer free-standing films, loaded homogeneously with 2% wt. carbon coated iron nanoparticles, were ablated by UV (248 nm), nanosecond laser pulses. The laser irradiation induces chemical and structural changes (both in micro- and nano-scale) to the surfaces of the nanocomposites rendering them superhydrophobic. The use of nanoparticles increases the UV light absorption efficiency of the nanocomposite samples, and thus facilitates the ablation process, since the number of pulses and the laser fluence required are greatly reduced compared to the bare polymer. Additionally the magnetic nanoparticles enhance significantly the superhydrophobic and oleophilic properties of the PDMS sheets, and provide to PDMS magnetic properties making possible its actuation by a weak external magnetic field. These nanocomposite elastomers can be considered for applications requiring magnetic MEMS for the controlled separation of liquids.

  4. Debilitating clinical disease in a wild-born captive western lowland gorilla (Gorilla gorilla gorilla) co-infected with varicella zoster virus (VZV) and simian T-lymphotropic virus (STLV).

    Science.gov (United States)

    Masters, Nicholas; Niphuis, Henk; Verschoor, Ernst; Breuer, Judith; Quinlivan, Mark; Wawrzynczyk, Teresa; Stidworthy, Mark

    2010-12-01

    A wild-born, 34-yr-old female western lowland gorilla (Gorilla gorilla gorilla) was transferred between zoologic collections in the United Kingdom. Adjustment to its new environment was difficult and a series of health problems ensued. Progressive severe illness of multiple etiologies, and a failure to respond to multiple therapies, led to its euthanasia 5 mo later. Disease processes included severe thoracic and axillary cutaneous ulceration of T2-3 dermatome distribution, gastroenteritis, ulcerative stomatitis, emaciation, hind limb weakness or paresis, and decubitus ulcers of the ankles and elbows. Ante- and postmortem infectious disease screening revealed that this animal was not infected with Mycobacterium tuberculosis, simian varicella virus (SVV), simian immunodeficiency virus (SIV), or hepatitis B virus; but was infected with varicella-zoster virus (VZV) and simian T-lymphotropic virus (STLV). It is hypothesized that recrudescence of VZV and other disease processes described were associated with chronic STLV infection and the end of a characteristically long incubation period.

  5. Core-shell magnetite-silica composite nanoparticles enhancing DNA damage induced by a photoactive platinum-diimine complex in red light.

    Science.gov (United States)

    Zhang, Zhigang; Chai, Aiyun

    2012-12-01

    Lack of solubility under physiological conditions poses an additional risk for toxicity and side effects for intravenous delivery of the photodynamic therapeutic agent in vivo. Employing magnetite-silica composite nanoparticles as carriers of the photodynamic therapeutic agents may be a promising way to solve the problem. In this study, core-shell magnetite-silica composite nanoparticles were prepared by a sol-gel method, and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and dynamic light scattering, then they were used as carriers of a photoactive platinum diimine complex. The interactions of the photosensitizer-loaded magnetic composite nanoparticles with DNA in red light were monitored by agarose-gel electrophoresis. The results suggest that high doses of magnetite-silica composite nanoparticles might facilitate the transformation of covalently closed circular (ccc)-DNA band to open circular (oc)-DNA band though they are harmless to DNA at their low concentrations, therefore enhancing the extent of DNA damage caused by the metal complex in red light.

  6. Glycyrrhetinic acid-modified chitosan nanoparticles enhanced the effect of 5-fluorouracil in murine liver cancer model via regulatory T-cells

    Directory of Open Access Journals (Sweden)

    Cheng M

    2013-10-01

    Full Text Available Mingrong Cheng,1,2,* Hongzhi Xu,3,* Yong Wang,4,* Houxiang Chen,5 Bing He,3 Xiaoyan Gao,6 Yingchun Li,2 Jiang Han,1 Zhiping Zhang1 1Department of General Surgery, 2Department of Endoscopy, Pudong New Area District Zhoupu Hospital, Shanghai, People’s Republic of China; 3Department of General Surgery, Shanghai Fifth People’s Hospital, Fudan University, Shanghai, People’s Republic of China; 4School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, People’s Republic of China; 5Zhejiang Huafon Fiber Research Institute, Zhejiang Huafon Spandex Co, Ltd, Wenzhou, People’s Republic of China; 6Department of Plastic Surgery, Pudong New Area District Zhoupu Hospital, Shanghai, People’s Republic of China *These authors contributed equally to this work Abstract: Modified chitosan nanoparticles are a promising platform for drug, such as 5-fluorouracil (5-FU, gene, and vaccine delivery. Here, we used chitosan and hepatoma cell-specific binding molecule glycyrrhetinic acid (GA to synthesize glycyrrhetinic acid-modified chitosan (GA-CTS. The synthetic product was confirmed by infrared spectroscopy and hydrogen nuclear magnetic resonance. By combining GA-CTS and 5-FU, we obtained a GA-CTS/5-FU nanoparticle, with a particle size of 193.7 nm, drug loading of 1.56%, and a polydispersity index of 0.003. The GA-CTS/5-FU nanoparticle provided a sustained-release system comprising three distinct phases of quick, steady, and slow release. In vitro data indicated that it had a dose- and time-dependent anticancer effect. The effective drug exposure time against hepatic cancer cells was increased in comparison with that observed with 5-FU. In vivo studies on an orthotropic liver cancer mouse model demonstrated that GA-CTS/5-FU significantly inhibited cancer cell proliferation, resulting in increased survival time. The antitumor mechanisms for GA-CTS/5-FU nanoparticle were possibly associated with an increased expression of regulatory T

  7. Magnetism and magnetic materials

    CERN Document Server

    Coey, J M D

    2010-01-01

    Covering basic physical concepts, experimental methods, and applications, this book is an indispensable text on the fascinating science of magnetism, and an invaluable source of practical reference data. Accessible, authoritative, and assuming undergraduate familiarity with vectors, electromagnetism and quantum mechanics, this textbook is well suited to graduate courses. Emphasis is placed on practical calculations and numerical magnitudes - from nanoscale to astronomical scale - focussing on modern applications, including permanent magnet structures and spin electronic devices. Each self-contained chapter begins with a summary, and ends with exercises and further reading. The book is thoroughly illustrated with over 600 figures to help convey concepts and clearly explain ideas. Easily digestible tables and data sheets provide a wealth of useful information on magnetic properties. The 38 principal magnetic materials, and many more related compounds, are treated in detail

  8. Nanoparticle enhanced ionic liquid heat transfer fluids

    Science.gov (United States)

    Fox, Elise B.; Visser, Ann E.; Bridges, Nicholas J.; Gray, Joshua R.; Garcia-Diaz, Brenda L.

    2014-08-12

    A heat transfer fluid created from nanoparticles that are dispersed into an ionic liquid is provided. Small volumes of nanoparticles are created from e.g., metals or metal oxides and/or alloys of such materials are dispersed into ionic liquids to create a heat transfer fluid. The nanoparticles can be dispersed directly into the ionic liquid during nanoparticle formation or the nanoparticles can be formed and then, in a subsequent step, dispersed into the ionic liquid using e.g., agitation.

  9. High seroprevalence of human T-cell lymphotropic virus type 1 in blood donors in Guyana and molecular and phylogenetic analysis of new strains in the Guyana shelf (Guyana, Suriname, and French Guiana).

    Science.gov (United States)

    Pouliquen, Jean-François; Hardy, Lynette; Lavergne, Anne; Kafiludine, Eric; Kazanji, Mirdad

    2004-05-01

    The prevalence of human T-cell lymphotropic virus type 1 (HTLV-1) and HTLV-2 in blood donors in Guyana has never been estimated. We evaluated the prevalence of these viruses in blood donors by enzyme-linked immunosorbent assay and Western blotting and showed a prevalence of HTLV-1 of 1.3%; no HTLV-2 was detected. Female donors had a much higher HTLV-1 seroprevalence (3.6%) than male donors (0.7%). HTLV-1-seropositive donors tended to be slightly older than the average age for the total pool of donors. We also investigated the phylogenetic and molecular characteristics of HTLV-1 strains in Guyana and compared them with those identified in Suriname and French Guiana. Analysis of portions of the env and long terminal repeat nucleotide sequences showed that all the strains in Guyana and Suriname, like those in French Guiana, belonged to the transcontinental group of cosmopolitan subtype A. The similarities were greater between strains from Suriname and Guyana than between strains from Suriname and Guyana and those from French Guiana. Nevertheless, our results confirm that the HTLV-1 strains in all three countries have a common African origin.

  10. Mother-to-Child Transmission of Human T-Cell Lymphotropic Viruses-1/2: What We Know, and What Are the Gaps in Understanding and Preventing This Route of Infection

    Science.gov (United States)

    Carneiro-Proietti, A. B. F.; Amaranto-Damasio, M. S.; Leal-Horiguchi, C. F.; Bastos, R. H. C.; Seabra-Freitas, G.; Borowiak, D. R.; Ribeiro, M. A.; Proietti, F. A.; Ferreira, A. S. D.; Martins, M. L.

    2014-01-01

    Although human T-cell lymphotropic viruses (HTLV-1/2) were described over 30 years ago, they are relatively unknown to the public and even to healthcare personnel. Although HTLV-1 is associated with severe illnesses, these occur in only approximately 10% of infected individuals, which may explain the lack of public knowledge about them. However, cohort studies are showing that a myriad of other disease manifestations may trouble infected individuals and cause higher expenditures with healthcare. Testing donated blood for HTLV-1/2 started soon after reliable tests were developed, but unfortunately testing is not available for women during prenatal care. Vertical transmission can occur before or after birth of the child. Before birth, it occurs transplacentally or by transfer of virus during cesarean delivery, but these routes of infection are rare. After childbirth, viral transmission occurs during breastfeeding and increases with longer breastfeeding and high maternal proviral load. Unlike the human immunodeficiency virus types 1 and 2, HTLV is transmitted primarily through breastfeeding and not transplacentally or during delivery. In this study, we review what is currently known about HTLV maternal transmission, its prevention, and the gaps still present in the understanding of this process. PMID:25232474

  11. Human T-lymphotropic virus 1 (HTLV-1)-associated lichenoid dermatitis induced by CD8+ T cells in HTLV-1 carrier, HTLV-1-associated myelopathy/tropical spastic paraparesis and adult T-cell leukemia/lymphoma.

    Science.gov (United States)

    Tokura, Yoshiki; Ito, Taisuke; Kawakami, Chika; Sugita, Kazunari; Kasuya, Akira; Tatsuno, Kazuki; Sawada, Yu; Nakamura, Motonobu; Shimauchi, Takatoshi

    2015-10-01

    Human T-lymphotropic virus type 1 (HTLV-1) induces adult T-cell leukemia/lymphoma (ATLL), HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and carrier. ATLL is a mature CD4+ CD25+ CCR4+ T-cell neoplasm, and approximately half of patients have direct skin involvement manifesting patch, plaque, tumor, multiple papules, erythroderma and purpura. However, there exist secondary eruptions without tumor cell infiltration in patients with ATLL or HAM/TSP and carriers of HTLV-1. To clarify the presence of reactive skin eruptions in HTLV-1-infected individuals, we reviewed our patients with HTLV-1-associated diseases. In 2002-2012, we saw 50 ATLL or HAM/TSP patients and HTLV-1 carriers presenting with skin lesions. We retrospectively selected cases that histologically showed lichenoid tissue reactions with predominant infiltration of CD8+ T cells, but not CD4+ tumor cells. The cases included erythroderma (HTLV-1 carrier), lichen planus (HTLV-1 carrier), alopecia areata (HAM/TSP), chronic actinic dermatitis (HTLV-1 carrier to acute ATLL conversion) and discoid lupus erythematosus (smoldering ATLL). They were graft-versus-host disease-like, major secondary lesions and seen in HTLV-1 carriers and patients with HAM/TSP and smoldering ATLL. We coin the term HTLV-1-associated lichenoid dermatitis (HALD) to encompass the conditions. HALD may occur in association with the elevated immunity toward HTLV-1-infected CD4+ T cells, thus sharing the pathogenetic role of cytotoxic T cells with HAM/TSP.

  12. Magnetic Levitation.

    Science.gov (United States)

    Rossing, Thomas D.; Hull, John R.

    1991-01-01

    Discusses the principles of magnetic levitation presented in the physics classroom and applied to transportation systems. Topics discussed include three classroom demonstrations to illustrate magnetic levitation, the concept of eddy currents, lift and drag forces on a moving magnet, magnetic levitation vehicles, levitation with permanent magnets…

  13. Magnetic Levitation.

    Science.gov (United States)

    Rossing, Thomas D.; Hull, John R.

    1991-01-01

    Discusses the principles of magnetic levitation presented in the physics classroom and applied to transportation systems. Topics discussed include three classroom demonstrations to illustrate magnetic levitation, the concept of eddy currents, lift and drag forces on a moving magnet, magnetic levitation vehicles, levitation with permanent magnets…

  14. Magnetic Nanocapsules

    Institute of Scientific and Technical Information of China (English)

    Zhidong ZHANG

    2007-01-01

    A brief review on recent advances in the area of the magnetic nanocapsules is given. The most applicable nanoencapsulation procedures are introduced, which include: (1) physical techniques such as arc-discharge,evaporating, etc.; (2) chemical techniques such as chemical vapor deposition, solid-state reactions, etc. The structure and magnetic properties of various nanocapsules with different core/shell structures are studied in details, for possibly applications in magnetic recording, magnetic refrigerator, magnetic fluids, superconductors and medicine.

  15. 对嗜T淋巴细胞病毒Ⅰ型重组env的研究%Study on the expression of recombinant antigen env in human T-cell lymphotropic virus type into prokaryotic vector I

    Institute of Scientific and Technical Information of China (English)

    朱庆华; 王梅芬

    2012-01-01

    Objective To investigate the expression of recombinant antigen env in human T-cell lymphotropic virus type I. Methods The target gene of HTLV-I env were analyzed and selected, cloned into prokaryotic vector pQE80L and identified it through PCR and restriction methods. Then the expressed recombinant env protein antigen was induced and purified by affinity chromatography. Western—blot method was adapted to test the activity of the recombinant env antigen expressed by prokaryotic, and ELISA method was adapted to test its specificity. Results The positive recombinants pQE80L-env was selected through PCR amplification and restriction. SDS-PAGE suggested the relative molecular mass of the recombinant protein was approximately 25KDa,which was in line with the expected molecular weight,and Western-blot showed an obvious specific band at 25KDa. The transfected cells were cultured for 48h,then the corresponding SDS-PAGE indicated the relative molecular mass of the recombinant protein was approximately 27KDa,which coincided with the expected molecular weight,and Western-blot revealed an obvious specific band at 27KDa. The reference sera of normal, HIV-positive and HTLV- II -positive people were all detected negative, while HTLV- I -positive people was strongly positive. Conclusion 5915-6545nt area of HTLV-I env gene can be cloned into prokaryotic and eukaryotic vector to express the specific recombinant antigen HTLV-I. There are no significant differences between the two antigens,and it holds the potential to be used as test kits.%目的 探讨人类嗜T淋巴细胞病毒( Human T-cell Lymphotropic Virus,HTLV)I型重组env抗原的表达.方法 分析和选择HTLV-Ⅰ env目的基因,将目的基因片段分别克隆人原核表达载体pQE80L,PCR和酶切鉴定重组子,诱导并亲和层析纯化表达重组env蛋白抗原,Western-blot检测重组env蛋白抗原活性,ELISA方法测试重组env蛋白抗原的特异性.结果 PCR扩增和酶切筛

  16. Cell-Free versus Cell-to-Cell Infection by Human Immunodeficiency Virus Type 1 and Human T-Lymphotropic Virus Type 1: Exploring the Link among Viral Source, Viral Trafficking, and Viral Replication.

    Science.gov (United States)

    Dutartre, Hélène; Clavière, Mathieu; Journo, Chloé; Mahieux, Renaud

    2016-09-01

    Human immunodeficiency virus type 1 (HIV-1) and human T-lymphotropic virus type 1 (HTLV-1) are complex retroviruses mainly infecting CD4(+) T lymphocytes. In addition, antigen-presenting cells such as dendritic cells (DCs) are targeted in vivo by both viruses, although to a lesser extent. Interaction of HIV-1 with DCs plays a key role in viral dissemination from the mucosa to CD4(+) T lymphocytes present in lymphoid organs. While similar mechanisms may occur for HTLV-1 as well, most HTLV-1 data were obtained from T-cell studies, and little is known regarding the trafficking of this virus in DCs. We first compared the efficiency of cell-free versus cell-associated viral sources of both retroviruses at infecting DCs. We showed that both HIV-1 and HTLV-1 cell-free particles are poorly efficient at productively infecting DCs, except when DC-SIGN has been engaged. Furthermore, while SAMHD-1 accounts for restriction of cell-free HIV-1 infection, it is not involved in HTLV-1 restriction. In addition, cell-free viruses lead mainly to a nonproductive DC infection, leading to trans-infection of T-cells, a process important for HIV-1 spread but not for that of HTLV-1. Finally, we show that T-DC cell-to-cell transfer implies viral trafficking in vesicles that may both increase productive infection of DCs ("cis-infection") and allow viral escape from immune surveillance. Altogether, these observations allowed us to draw a model of HTLV-1 and HIV-1 trafficking in DCs.

  17. Tax posttranslational modifications and interaction with calreticulin in MT-2 cells and human peripheral blood mononuclear cells of human T cell lymphotropic virus type-I-associated myelopathy/tropical spastic paraparesis patients.

    Science.gov (United States)

    Medina, Fernando; Quintremil, Sebastian; Alberti, Carolina; Barriga, Andres; Cartier, Luis; Puente, Javier; Ramírez, Eugenio; Ferreira, Arturo; Tanaka, Yuetsu; Valenzuela, Maria Antonieta

    2014-04-01

    The human retrovirus human T cell lymphotropic virus type-I (HTLV-1) is the etiologic agent of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Axonal degeneration in HAM/TSP patients occurs without neuron infection, with the secreted viral Tax protein proposed to be involved. We previously found that Tax secreted into the culture medium of MT-2 cells (HTLV-1-infected cell line) produced neurite retraction in neuroblastoma cells differentiated to neuronal type. To assess the relevance of Tax posttranslational modifications on this effect, we addressed the question of whether Tax secreted by MT-2 cells and peripheral blood mononuclear cells (PBMCs) of HTLV-1-infected subjects is modified. The interaction of Tax with calreticulin (CRT) that modulates intracellular Tax localization and secretion has been described. We studied Tax localization and modifications in MT-2 cells and its interaction with CRT. Intracellular Tax in MT-2 cells was assessed by flow cytometry, corresponding mainly to a 71-kDa protein followed by western blot. This protein reported as a chimera with gp21 viral protein-confirmed by mass spectrometry-showed no ubiquitination or SUMOylation. The Tax-CRT interaction was determined by confocal microscopy and coimmunoprecipitation. Extracellular Tax from HAM/TSP PBMCs is ubiquitinated according to western blot, and its interaction with CRT was shown by coimmunoprecipitation. A positive correlation between Tax and CRT secretion was observed in HAM/TSP PBMCs and asymptomatic carriers. For both proteins inhibitors and activators of secretion showed secretion through the endoplasmic reticulum-Golgi complex. Tax, present in PBMC culture medium, produced neurite retraction in differentiated neuroblastoma cells. These results suggest that Tax, whether ubiquitinated or not, is active for neurite retraction.

  18. Tax secretion from peripheral blood mononuclear cells and Tax detection in plasma of patients with human T-lymphotropic virus-type 1-associated myelopathy/tropical spastic paraparesis and asymptomatic carriers.

    Science.gov (United States)

    Medina, Fernando; Quintremil, Sebastián; Alberti, Carolina; Godoy, Fabián; Pando, María E; Bustamante, Andrés; Barriga, Andrés; Cartier, Luis; Puente, Javier; Tanaka, Yuetsu; Valenzuela, María A; Ramírez, Eugenio

    2016-03-01

    Human T-lymphotropic virus-type 1 (HTLV-1) is the etiologic agent of the neurologic disease HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Tax viral protein plays a critical role in viral pathogenesis. Previous studies suggested that extracellular Tax might involve cytokine-like extracellular effects. We evaluated Tax secretion in 18 h-ex vivo peripheral blood mononuclear cells (PBMCs) cultures from 15 HAM/TSP patients and 15 asymptomatic carriers. Futhermore, Tax plasma level was evaluated from other 12 HAM/TSP patients and 10 asymptomatic carriers. Proviral load and mRNA encoding Tax were quantified by PCR and real-time RT-PCR, respectively. Intracellular Tax in CD4(+)CD25(+) cells occurred in 100% and 86.7% of HAM/TSP patients and asymptomatic carriers, respectively. Percentage of CD4(+)CD25(+) Tax+, proviral load and mRNA encoding Tax were significantly higher in HAM/TSP patients. Western blot analyses showed higher secretion levels of ubiquitinated Tax in HAM/TSP patients than in asymptomatic carriers. In HTLV-1-infected subjects, Western blot of plasma Tax showed higher levels in HAM/TSP patients than in asymptomatic carriers, whereas no Tax was found in non-infected subjects. Immunoprecipitated plasma Tax resolved on SDS-PAGE gave two major bands of 57 and 48 kDa allowing identification of Tax and Ubiquitin peptides by mass spectrometry. Relative percentage of either CD4(+)CD25(+) Tax+ cells, or Tax protein released from PBMCs, or plasma Tax, correlates neither with tax mRNA nor with proviral load. This fact could be explained by a complex regulation of Tax expression. Tax secreted from PBMCs or present in plasma could potentially become a biomarker to distinguish between HAM/TSP patients and asymptomatic carriers.

  19. Tumor necrosis factor alpha inhibitors have no effect on a human T-lymphotropic virus type-I (HTLV-I)-infected cell line from patients with HTLV-I-associated myelopathy.

    Science.gov (United States)

    Fukui, Shoichi; Nakamura, Hideki; Takahashi, Yoshiko; Iwamoto, Naoki; Hasegawa, Hiroo; Yanagihara, Katsunori; Nakamura, Tatsufumi; Okayama, Akihiko; Kawakami, Atsushi

    2017-02-03

    While tumor necrosis factor alpha (TNF-α) inhibitors (TNFi) and other biologics are very effective against autoimmune diseases, they can also cause infectious diseases. Therefore, it is important to clarify whether the TNFi sometimes used to treat patients with rheumatoid arthritis (RA) complicated with human T-lymphotropic virus type-I (HTLV-I) infection have the unintended side effect of promoting HTLV-I proliferation. We used the HTLV-I-infected cell line HCT-5, derived from spinal fluid cells of a patient with HTLV-I associated myelopathy, to evaluate the production of cytokines and chemokines, TNF-α receptor (TNFR), the expression of HTLV-I associated genes, the HTLV-I proviral load (PVL), the expression of HTLV-I structural protein, and apoptosis. We used Jurkat cells as a control. Supernatants of HCT-5 showed time-dependent elevations of IL-6, RANTES and ICAM-1. HCT-5 supernatants treated with infliximab, adalimumab, etanercept (ETN), golimumab and certolizumab pegol showed no significant differences in the levels of these molecules compared to the control. Neither TNFR1 nor TNFR2 expression was altered by any TNFi treatment, relative to phosphate-buffered saline (PBS) treatment, with the exception that TNFR2 was significantly decreased and internalized in HCT-5 cells by ETN treatment. The HTLV-I associated genes Tax and HBZ and the PVL levels were not significantly changed. Immunofluorescence staining of HCT-5 for an HTLV-I-associated protein, GAG, was also not significantly different between any of the TNFi treatments and the PBS treatment. DNA ladders as an index of apoptosis were not detected. Apoptotic cells were not increased by the addition of any TNFi. In vitro, TNFi did not affect the cytokine profiles, expression of associated genes and proteins, proviral load or apoptosis of HCT-5 cells. The results suggested that TNFi treatment of RA patients complicated with HTLV-I might have no effect on HTLV-I infection.

  20. Magnetic Reconnection

    NARCIS (Netherlands)

    Schep, T. J.

    1994-01-01

    This lecture deals with the concept of magnetic field lines and with the conservation of magnetic flux. In high temperature fusion devices like tokamaks flux conservation can be violated and reconnection can occur at closed magnetic field lines. Reconnection processes lead to changes in the global t

  1. Magnetizing of permanent magnets using HTS bulk magnets

    Science.gov (United States)

    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.

  2. Magnetic investigations

    Energy Technology Data Exchange (ETDEWEB)

    Bath, G.D.; Jahren, C.E.; Rosenbaum, J.G. [Geological Survey, Denver, CO (USA); Baldwin, M.J. [Fenix and Scisson, Inc., Mercury, NV (USA)

    1983-12-31

    Air and ground magnetic anomalies in the Climax stock area of the NTS help define the gross configuration of the stock and detailed configuration of magnetized rocks at the Boundary and Tippinip faults that border the stock. Magnetizations of geologic units were evaluated by measurements of magnetic properties of drill core, minimum estimates of magnetizations from ground magnetic anomalies for near surface rocks, and comparisons of measured anomalies with anomalies computed by a three-dimensional forward program. Alluvial deposits and most sedimentary rocks are nonmagnetic, but drill core measurements reveal large and irregular changes in magnetization for some quartzites and marbles. The magnetizations of quartz monzonite and granodiorite near the stock surface are weak, about 0.15 A/m, and increase at a rate of 0.00196 A/m/m to 1.55 A/m, at depths greater than 700 m (2300 ft). The volcanic rocks of the area are weakly magnetized. Aeromagnetic anomalies 850 m (2800 ft) above the stock are explained by a model consisting of five vertical prisms. Prisms 1, 2, and 3 represent the near surface outline of the stock, prism 4 is one of the models developed by Whitehill (1973), and prism 5 is modified from the model developed by Allingham and Zietz (1962). Most of the anomaly comes from unsampled and strongly-magnetized deep sources that could be either granite or metamorphosed sedimentary rocks. 48 refs., 23 figs., 3 tabs.

  3. Planetary Magnetism

    Science.gov (United States)

    Connerney, J. E. P.

    2007-01-01

    The chapter on Planetary Magnetism by Connerney describes the magnetic fields of the planets, from Mercury to Neptune, including the large satellites (Moon, Ganymede) that have or once had active dynamos. The chapter describes the spacecraft missions and observations that, along with select remote observations, form the basis of our knowledge of planetary magnetic fields. Connerney describes the methods of analysis used to characterize planetary magnetic fields, and the models used to represent the main field (due to dynamo action in the planet's interior) and/or remnant magnetic fields locked in the planet's crust, where appropriate. These observations provide valuable insights into dynamo generation of magnetic fields, the structure and composition of planetary interiors, and the evolution of planets.

  4. Quantum Magnetism

    CERN Document Server

    Barbara, Bernard; Sawatzky, G; Stamp, P. C. E

    2008-01-01

    This book is based on some of the lectures during the Pacific Institute of Theoretical Physics (PITP) summer school on "Quantum Magnetism", held during June 2006 in Les Houches, in the French Alps. The school was funded jointly by NATO, the CNRS, and PITP, and entirely organized by PITP. Magnetism is a somewhat peculiar research field. It clearly has a quantum-mechanical basis – the microsopic exchange interactions arise entirely from the exclusion principle, in conjunction with respulsive interactions between electrons. And yet until recently the vast majority of magnetism researchers and users of magnetic phenomena around the world paid no attention to these quantum-mechanical roots. Thus, eg., the huge ($400 billion per annum) industry which manufactures hard discs, and other components in the information technology sector, depends entirely on room-temperature properties of magnets - yet at the macroscopic or mesoscopic scales of interest to this industry, room-temperature magnets behave entirely classic...

  5. Magnetics Processing

    Data.gov (United States)

    Federal Laboratory Consortium — The Magnetics Processing Lab equipped to perform testing of magnetometers, integrate them into aircraft systems, and perform data analysis, including noise reduction...

  6. Magnet Systems

    Data.gov (United States)

    Federal Laboratory Consortium — Over the decades, Fermilab has been responsible for the design, construction, test and analysis of hundreds of conventional and superconducting accelerator magnets...

  7. Magnetic Field

    DEFF Research Database (Denmark)

    Olsen, Nils

    2015-01-01

    of the fluid flow at the top of the core. However, what is measured at or near the surface of the Earth is the superposition of the core field and fields caused by magnetized rocks in the Earth’s crust, by electric currents flowing in the ionosphere, magnetosphere, and oceans, and by currents induced......he Earth has a large and complicated magnetic field, the major part of which is produced by a self-sustaining dynamo operating in the fluid outer core. Magnetic field observations provide one of the few tools for remote sensing the Earth’s deep interior, especially regarding the dynamics...... in the Earth by time-varying external fields. These sources have their specific characteristics in terms of spatial and temporal variations, and their proper separation, based on magnetic measurements, is a major challenge. Such a separation is a prerequisite for remote sensing by means of magnetic field...

  8. Magnetic nanotubes

    Science.gov (United States)

    Matsui, Hiroshi; Matsunaga, Tadashi

    2010-11-16

    A magnetic nanotube includes bacterial magnetic nanocrystals contacted onto a nanotube which absorbs the nanocrystals. The nanocrystals are contacted on at least one surface of the nanotube. A method of fabricating a magnetic nanotube includes synthesizing the bacterial magnetic nanocrystals, which have an outer layer of proteins. A nanotube provided is capable of absorbing the nanocrystals and contacting the nanotube with the nanocrystals. The nanotube is preferably a peptide bolaamphiphile. A nanotube solution and a nanocrystal solution including a buffer and a concentration of nanocrystals are mixed. The concentration of nanocrystals is optimized, resulting in a nanocrystal to nanotube ratio for which bacterial magnetic nanocrystals are immobilized on at least one surface of the nanotubes. The ratio controls whether the nanocrystals bind only to the interior or to the exterior surfaces of the nanotubes. Uses include cell manipulation and separation, biological assay, enzyme recovery, and biosensors.

  9. Magnetic Bearing

    Science.gov (United States)

    1996-01-01

    AVCON, Inc. produces advanced magnetic bearing systems for industrial use, offering a unique technological approach based on contract work done at Marshall Space Flight Center and Lewis Research Center. Designed for the turbopump of the Space Shuttle main engine, they are now used in applications such as electric power generation, petroleum refining, machine tool operation and natural gas pipelines. Magnetic bearings support moving machinery without physical contact; AVCON's homopolar approach is a hybrid of permanent and electromagnets which are one-third the weight, smaller and more power- efficient than previous magnetic bearings.

  10. Lunar magnetism

    Science.gov (United States)

    Hood, L. L.; Sonett, C. P.; Srnka, L. J.

    1984-01-01

    Aspects of lunar paleomagnetic and electromagnetic sounding results which appear inconsistent with the hypothesis that an ancient core dynamo was the dominant source of the observed crustal magnetism are discussed. Evidence is summarized involving a correlation between observed magnetic anomalies and ejecta blankets from impact events which indicates the possible importance of local mechanisms involving meteoroid impact processes in generating strong magnetic fields at the lunar surface. A reply is given to the latter argument which also presents recent evidence of a lunar iron core.

  11. Designing a magnet for magnetic refrigeration

    DEFF Research Database (Denmark)

    Bjørk, Rasmus

    of infinite length, are presented. Once it has been determined which properties are desirable for a magnet used in magnetic refrigeration the design of a new magnet is described. This is a high performance cylindrical magnet for use in a new magnetic refrigeration device being built at Risø DTU. This magnet...

  12. CRYOGENIC MAGNETS

    Science.gov (United States)

    Post, R.F.; Taylor, C.E.

    1963-05-21

    A cryogenic magnet coil is described for generating magnetic fields of the order of 100,000 gauss with a minimum expenditure of energy lost in resistive heating of the coil inductors and energy lost irreversibly in running the coil refrigeration plant. The cryogenic coil comprises a coil conductor for generating a magnetic field upon energization with electrical current, and refrigeration means disposed in heat conductive relation to the coil conductor for cooling to a low temperature. A substantial reduction in the power requirements for generating these magnetic fields is attained by scaling the field generating coil to large size and particular dimensions for a particular conductor, and operating the coil at a particular optimum temperature commensurate with minimum overall power requirements. (AEC)

  13. Quantum magnetism

    CERN Document Server

    Richter, Johannes; Farnell, Damian; Bishop, Raymod

    2004-01-01

    The investigation of magnetic systems where quantum effects play a dominant role has become a very active branch of solid-state-physics research in its own right. The first three chapters of the "Quantum Magnetism" survey conceptual problems and provide insights into the classes of systems considered, namely one-dimensional, two-dimensional and molecular magnets. The following chapters introduce the methods used in the field of quantum magnetism, including spin wave analysis, exact diagonalization, quantum field theory, coupled cluster methods and the Bethe ansatz. The book closes with a chapter on quantum phase transitions and a contribution that puts the wealth of phenomena into the context of experimental solid-state physics. Closing a gap in the literature, this volume is intended both as an introductory text at postgraduate level and as a modern, comprehensive reference for researchers in the field.

  14. Magnetization reversal in ultrashort magnetic field pulses

    CERN Document Server

    Bauer, M; Fassbender, J; Hillebrands, B

    2000-01-01

    We report the switching properties of a thin magnetic film subject to an ultrashort, laterally localized magnetic field pulse, obtained by numerical investigations. The magnetization distribution in the film is calculated on a grid assuming Stoner-like coherent rotation within the grid square size. Perpendicularly and in-plane magnetized films exhibit a magnetization reversal due to a 4 ps magnetic field pulse. Outside the central region the pulse duration is short compared to the precession period. In this area the evolution of the magnetization during the field pulse does not depend strongly on magnetic damping and/or pulse shape. However, the final magnetization distribution is affected by the magnetic damping. Although the pulse duration is short compared to the precession period, the time needed for the relaxation of the magnetization to the equilibrium state is rather large. The influence of the different magnetic anisotropy contributions and the magnetic damping parameter enters into the magnetization ...

  15. An optimized magnet for magnetic refrigeration

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Bahl, Christian Robert Haffenden; Smith, Anders

    2010-01-01

    A magnet designed for use in a magnetic refrigeration device is presented. The magnet is designed by applying two general schemes for improving a magnet design to a concentric Halbach cylinder magnet design and dimensioning and segmenting this design in an optimum way followed by the construction...... to the maximum energy density. The final design is characterized in terms of a performance parameter, and it is shown that it is one of the best performing magnet designs published for magnetic refrigeration....

  16. Magnetism Materials and Applications

    CERN Document Server

    Trémolet de Lacheisserie, Étienne; Schlenker, Michel

    2005-01-01

    This book treats permanent magnet (hard) materials, magnetically soft materials for low-frequency applications and for high-frequency electronics, magnetostrictive materials, superconductors, magnetic-thin films and multilayers, and ferrofluids. Chapters are dedicated to magnetic recording, the role of magnetism in magnetic resonance imaging (MRI), and instrumentation for magnetic measurements.   

  17. Magnetic monopoles and dipoles

    CERN Multimedia

    Dominguez, Daniel

    2016-01-01

    Conventional bar magnets are also called ‘magnetic dipoles’ because they have two magnetic poles (a “North” and a “South” magnetic pole, like the Earth). In theory, “magnetic monopoles” could exist that act like an isolated “magnetic charge”, i.e. either a “North” or a “South” magnetic pole.

  18. Designing a magnet for magnetic refrigeration

    Energy Technology Data Exchange (ETDEWEB)

    Bjoerk, R.

    2010-03-15

    This thesis investigates the design and optimization of a permanent magnet assembly for use in a magnetic refrigeration device. The heart of magnetic refrigeration is the adiabatic temperature change in the magnetocaloric material which is caused by the magnetic field. In order to design an ideal magnet assembly the magnetocaloric materials and the refrigeration process itself and their properties and performance as a function of magnetic field are investigated. For the magnetocaloric materials it is the magnetization, specific heat capacity and adiabatic temperature that are investigated as functions of the magnetic field. Following this the process utilized by a magnetic refrigerator to provide cooling is investigated using a publicly available one dimensional numerical model. This process is called active magnetic regeneration (AMR). The aim is to determine the performance of the AMR as a function of the magnetic field in order to learn the properties of the optimal magnet assembly. The performance of the AMR as a function of the synchronization and width of the magnetic field with respect to the AMR cycle, the ramp rate and maximum value of the magnetic field are investigated. Other published magnet designs used in magnetic refrigeration devices are also evaluated, using a figure of merit based on the properties of the investigated magnetocaloric materials, to learn the properties of the best magnet designs to date. Following this investigation the Halbach cylinder, which is a hollow permanent magnet cylinder with a rotating remanent flux density, is investigated in detail as it forms the basis of many magnet designs used in magnetic refrigeration. Here the optimal dimensions of a Halbach cylinder, as well as analytical calculations of the magnetic field for a Halbach cylinder of infinite length, are presented. Once it has been determined which properties are desirable for a magnet used in magnetic refrigeration the design of a new magnet is described. This is

  19. Magnetic guns with cylindrical permanent magnets

    DEFF Research Database (Denmark)

    Vokoun, David; Beleggia, Marco; Heller, Luděk

    2012-01-01

    The motion of a cylindrical permanent magnet (projectile) inside a tubular permanent magnet, with both magnets magnetized axially, illustrates nicely the physical principles behind the operation of magnetic guns. The force acting upon the projectile is expressed semi-analytically as derivative...

  20. Magnetics Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Magnetics Research Facility houses three Helmholtz coils that generate magnetic fields in three perpendicular directions to balance the earth's magnetic field....

  1. Kicker magnet

    CERN Multimedia

    CERN PhotoLab

    1966-01-01

    The improved "bare" kicker magnet for the PS fast extraction system is here shown being mounted for testing a vacuum tank similar to the one in which it will be installed, early in 1967 in straight section 97 of the PS.

  2. Magnetic Fluids: Biomedical Applications and Magnetic Fractionation

    OpenAIRE

    Rheinländer, Thomas; Kötitz, Róman; Weitschies, Werner; Semmler, Wolfhard

    2000-01-01

    In addition to engineering applications, magnetic fluids containing magnetic nanoparticles are being increasingly applied to biomedical purposes. Besides the well established use of magnetic particles for biological separation or as contrast agents for magnetic resonance imaging, magnetic particles are also being tested for the inductive heat treatment of tumors or as markers for the quantification of biologically active substances. The properties of magnetic nanoparticles usually exhibit a b...

  3. LHC prototype magnet

    CERN Multimedia

    1991-01-01

    1.5 metre superconducting magnet. This prototype magnet for the LHC was cooled to a few degrees above absolute zero, which allowed it to obtain the world record for the highest magnetic field for an accelerator magnet in 1991.

  4. Magnetization curve modelling of soft magnetic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Meszaros, I, E-mail: meszaros@eik.bme.hu [Department of Materials Science and Engineering, Budapest University of Technology and Economics, Bertalan L. street 7., Budapest, H-1111 (Hungary)

    2011-01-01

    In this paper we present an application of the so called hyperbolic model of magnetization. The model was modified and it was applied for nine different soft magnetic alloys. The tested samples were electro-technical steels (FeSi alloys) and a permalloy (FeNi alloy) with strongly different magnetic properties. Among them there are top, medium and definitely poor quality soft magnetic materials as well. Their minor hysteresis loops and normal magnetization curves were measured by alternating current measurement. The hyperbolic model of magnetization was applied for the experimental normal magnetization curves. It was proved that the applied model is excellent for describing mathematically the experimental magnetization curves.

  5. magnetic horn

    CERN Multimedia

    Neutrinos and antineutrinos are ideal for probing the weak force because it is effectively the only force they feel. How were they made? Protons fired into a metal target produce a tangle of secondary particles. A magnetic horn like this one, invented by Simon Van der Meer, selected pions and focused them into a sharp beam. Pions decay into muons and neutrinos or antineutrinos. The muons were stopped in a wall of 3000 tons of iron and 1000 tons of concrete, leaving the neutrinos or antineutrinos to reach the Gargamelle bubble chamber. A simple change of magnetic field direction on the horn flipped between focusing positively- or negatively-charged pion beams, and so between neutrinos and antineutrinos.

  6. Magnetic switching

    Energy Technology Data Exchange (ETDEWEB)

    Birx, D.; Cook, E.; Hawkins, S.; Poor, S.; Reginato, L.; Schmidt, J.; Smith, M.

    1983-06-01

    The paper discusses the development program in magnetic switching which was aimed at solving the rep-rate and reliability limitations of the ATA spark gaps. The end result has been a prototype physically very similar to the present Advanced Test Accelerator (ATA) pulse power unit but vastly superior in performance. This prototype, which is easily adaptable to the existing systems, has achieved a burst rep-rate of 20 kHz and an output voltage of 500 kV. A one-on-one substitution of the existing pulse power module would result in a 100 MeV accelerator. Furthermore, the high efficiency of the magnetic pulse compression stages has allowed CW operation of the prototype at one kilohertz opening up other applications for the pulse power. Performance and design details will be described.

  7. Magnetic Reconnection

    Energy Technology Data Exchange (ETDEWEB)

    Masaaki Yamada, Russell Kulsrud and Hantao Ji

    2009-09-17

    We review the fundamental physics of magnetic reconnection in laboratory and space plasmas, by discussing results from theory, numerical simulations, observations from space satellites, and the recent results from laboratory plasma experiments. After a brief review of the well-known early work, we discuss representative recent experimental and theoretical work and attempt to interpret the essence of significant modern findings. In the area of local reconnection physics, many significant findings have been made with regard to two- uid physics and are related to the cause of fast reconnection. Profiles of the neutral sheet, Hall currents, and the effects of guide field, collisions, and micro-turbulence are discussed to understand the fundamental processes in a local reconnection layer both in space and laboratory plasmas. While the understanding of the global reconnection dynamics is less developed, notable findings have been made on this issue through detailed documentation of magnetic self-organization phenomena in fusion plasmas. Application of magnetic reconnection physics to astrophysical plasmas is also brie y discussed.

  8. Magnetic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Bihler, Christoph

    2009-04-15

    In this thesis we investigated in detail the properties of Ga{sub 1-x}Mn{sub x}As, Ga{sub 1-x}Mn{sub x}P, and Ga{sub 1-x}Mn{sub x}N dilute magnetic semiconductor thin films with a focus on the magnetic anisotropy and the changes of their properties upon hydrogenation. We applied two complementary spectroscopic techniques to address the position of H in magnetic semiconductors: (i) Electron paramagnetic resonance, which provides direct information on the symmetry of the crystal field of the Mn{sup 2+} atoms and (ii) x-ray absorption fine structure analysis which allows to probe the local crystallographic neighborhood of the absorbing Mn atom via analysing the fine structure at the Mn K absorption edge. Finally, we discussed the obstacles that have to be overcome to achieve Curie temperatures above the current maximum in Ga{sub 1-x}Mn{sub x}As of 185 K. Here, we outlined in detail the generic problem of the formation of precipitates at the example of Ge:MN. (orig.)

  9. MAGNET / INFRASTRUCTURE

    CERN Multimedia

    D. Campi

    The final fast discharge of the Magnet took place on 3rd of November. The Coil reached a temperature of 70K by internal energy dissipation. By injecting a current of 200 A room temperature was reached on the 23rd November. During the heating of the coil un-connecting of the first magnet connectors on YBO was started to give the earliest possible access to the assembly groups and to continue the installation of the muon chambers. The removal of the pumping lines and the disconnection of the vacuum system was instead done as soon as the room temperature was reached: more precisely from the 4 to the 18 December. The disconnection of the transfer line from the cold box and the completion of the removal of the control cables of the vacuum system and cryogenics was done at last. In January 2007 the disconnection of MCS-MSS, CDS, vacuum racks and their cable trays was also achieved. After coil disconnection the effort of the magnet team has been mainly devoted in optimizing the lowering and reassembly of the a...

  10. Enhancing the magnetic properties of magnetic nanoparticles

    DEFF Research Database (Denmark)

    Ahlburg, Jakob; Saura-Múzquiz, Matilde; Stingaciu, Marian

    ways of enhancing magnetic properties of 3d magnetic compounds. This includes, size control, core-shell particles or mixing hard and soft magnetic materials together to achieve an exchange coupling between the compounds and enhancing the magnetic energy product. In order to control the particle size......Enhancing the magnetic properties of magnetic nanoparticles J. V. Ahlburg, M. S. Músquiz, C. Zeuthen, S. Kjeldgaard, M. Stingaciu, M. Christensen Center for Materials Crystallography, Departement of Chemistry & iNano, Aarhus University, Denmark Strong magnets with a high energy product are vital...... when optimizing the efficiency in the electric industry. But since the rare earth metals, normally used for making strong permanent magnets, are both expensive and difficult to mine, a great demand has come to cheaper types of magnets with a similar magnetic performance. There are several different...

  11. Physics of magnetism and magnetic materials

    CERN Document Server

    Buschow, K H J

    2003-01-01

    In this book, the fundamentals of magnetism are treated, starting at an introductory level. The origin of magnetic moments, the response to an applied magnetic field, and the various interactions giving rise to different types of magnetic ordering in solids are presented and many examples are given. Crystalline-electric-field effects are treated at a level that is sufficient to provide the basic knowledge necessary in understanding the properties of materials in which these effects play a role. Itinerant-electron magnetism is presented on a similar basis. Particular attention has been given to magnetocrystalline magnetic anisotropy and the magnetocaloric effect. Also, the usual techniques for magnetic measurements are presented. About half of the book is devoted to magnetic materials and the properties that make them suitable for numerous applications. The state of the art is presented of permanent magnets, high-density recording materials, soft-magnetic materials, Invar alloys and magnetostrictive materials....

  12. Noncentrosymmetric Magnets Hosting Magnetic Skyrmions.

    Science.gov (United States)

    Kanazawa, Naoya; Seki, Shinichiro; Tokura, Yoshinori

    2017-03-17

    The concept of a skyrmion, which was first introduced by Tony Skyrme in the field of particle physics, has become widespread in condensed matter physics to describe various topological orders. Skyrmions in magnetic materials have recently received particular attention; they represent vortex-like spin structures with the character of nanometric particles and produce fascinating physical properties rooted in their topological nature. Here, a series of noncentrosymmetric ferromagnets hosting skyrmions is reviewed: B20 metals, Cu2 OSeO3 , Co-Zn-Mn alloys, and GaV4 S8 , where Dzyaloshinskii-Moriya interaction plays a key role in the stabilization of skyrmion spin texture. Their topological spin arrangements and consequent emergent electromagnetic fields give rise to striking features in transport and magnetoelectric properties in metals and insulators, such as the topological Hall effect, efficient electric-drive of skyrmions, and multiferroic behavior. Such electric controllability and nanometric particle natures highlight magnetic skyrmions as a potential information carrier for high-density magnetic storage devices with excellent energy efficiency.

  13. Fe3O4 nanoparticles for magnetic hyperthermia and drug delivery; synthesis, characterization and cellular studies

    Science.gov (United States)

    Palihawadana Arachchige, Maheshika

    with dextran functionalized FITC conjugated Fe3O4 nanoparticles, and our results demonstrate that there is a time-dependent distribution of these nanoparticles into different cellular compartments. Moreover, a novel conjugation of anti-cancer drug, Doxorubicin (Dox) with a labeling dye (FITC) onto dextran coated Fe3O4 nanoparticles was developed using existing EDC/NHS technique for specific drug targeting. The experiments on this unique drug-dye dual conjugation with human pancreatic cancer cell line (MIA PaCa-2) show that association of Dox onto the surface of nanoparticles enhances its penetration into the cancer cells as compared to the unconjugated drug while releasing Dox into the nucleus of the malignant cells.

  14. Magnetic fluids - suspensions of magnetic dipoles and their magnetic control

    CERN Document Server

    Odenbach, S

    2003-01-01

    Suspensions of magnetic nanoparticles exhibit normal liquid behaviour coupled with superparamagnetic properties. This leads to the possibility to control the properties and the flow of these liquids with moderate magnetic fields. The magnetic control enables various experiments in fluid mechanics and gives rise to the development of numerous technical and medical applications. Ferrofluids and their general properties will be introduced and, as examples for the magnetic control of their flow and properties, thermomagnetic convection and magnetoviscous effects will be discussed in some detail.

  15. Enhancing the magnetic properties of magnetic nanoparticles

    DEFF Research Database (Denmark)

    Ahlburg, Jakob; Saura-Múzquiz, Matilde; Stingaciu, Marian

    with a similar magnetic performance. There are several different ways of enhancing magnetic properties of 3d magnetic compounds. This includes, size control, core-shell particles or mixing hard and soft magnetic materials together to achieve an exchange coupling between the compounds and enhancing the magnetic......Strong magnets with a high energy product are vital when optimizing the efficiency in the electric industry. But since the rare earth metals, normally used for making strong permanent magnets, are both expensive and difficult to mine, a great demand has come to cheaper types of magnets...... energy product. In order to control the particle size, a hydrothermal synthesis is preferred. This followed by reduction or the oxides into either core shell particles, or a mixture of magnetic oxides and a metallic phase....

  16. Thin Magnetically Soft Wires for Magnetic Microsensors

    Directory of Open Access Journals (Sweden)

    Arcady Zhukov

    2009-11-01

    Full Text Available Recent advances in technology involving magnetic materials require development of novel advanced magnetic materials with improved magnetic and magneto-transport properties and with reduced dimensionality. Therefore magnetic materials with outstanding magnetic characteristics and reduced dimensionality have recently gained much attention. Among these magnetic materials a family of thin wires with reduced geometrical dimensions (of order of 1–30 μm in diameter have gained importance within the last few years. These thin wires combine excellent soft magnetic properties (with coercivities up to 4 A/m with attractive magneto-transport properties (Giant Magneto-impedance effect, GMI, Giant Magneto-resistance effect, GMR and an unusual re-magnetization process in positive magnetostriction compositions exhibiting quite fast domain wall propagation. In this paper we overview the magnetic and magneto-transport properties of these microwires that make them suitable for microsensor applications.

  17. Electrically Tunable Magnetism in Magnetic Topological Insulators

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jing; Lian, Biao; Zhang, Shou-Cheng

    2015-07-14

    The external controllability of the magnetic properties in topological insulators would be important both for fundamental and practical interests. Here we predict the electric-field control of ferromagnetism in a thin film of insulating magnetic topological insulators. The decrease of band inversion by the application of electric fields results in a reduction of magnetic susceptibility, and hence in the modification of magnetism. Remarkably, the electric field could even induce the magnetic quantum phase transition from ferromagnetism to paramagnetism. We further propose a transistor device in which the dissipationless charge transport of chiral edge states is controlled by an electric field. In particular, the field-controlled ferromagnetism in a magnetic topological insulator can be used for voltage based writing of magnetic random access memories in magnetic tunnel junctions. The simultaneous electrical control of magnetic order and chiral edge transport in such devices may lead to electronic and spintronic applications for topological insulators.

  18. MAGNETIC WOVEN FABRICS - PHYSICAL AND MAGNETIC PROPERTIES

    Directory of Open Access Journals (Sweden)

    GROSU Marian C

    2015-05-01

    Full Text Available A coated material is a composite structure that consists of at least two components: base material and coating layer. The purpose of coating is to provide special properties to base material, with potential to be applied in EMI shielding and diverse smart technical fields. This paper reports the results of a study about some physical and magnetic properties of coated woven fabrics made from cotton yarns with fineness of 17 metric count. For this aim, a plain woven fabric was coated with a solution hard magnetic polymer based. As hard magnetic powder, barium hexaferrite (BaFe12O19 was selected. The plain woven fabric used as base has been coated with five solutions having different amounts of hard magnetic powder (15% - 45% in order to obtain five different magnetic woven fabrics. A comparison of physical properties regarding weight (g/m2, thickness (mm, degree of charging (% and magnetic properties of magnetic woven samples were presented. Saturation magnetizing (emu/g, residual magnetizing (emu/g and coercive force (kA/m of pure hard magnetic powder and woven fabrics have been studied as hysteresis characteristics. The magnetic properties of the woven fabrics depend on the mass percentage of magnetic powder from coating solution. Also, the residual magnetism and coercive field of woven fabrics represents only a part of bulk barium hexafferite residual magnetism and coercive field.

  19. The magnetization process: Hysteresis

    Science.gov (United States)

    Balsamel, Richard

    1990-01-01

    The magnetization process, hysteresis (the difference in the path of magnetization for an increasing and decreasing magnetic field), hysteresis loops, and hard magnetic materials are discussed. The fabrication of classroom projects for demonstrating hysteresis and the hysteresis of common magnetic materials is described in detail.

  20. Magnetic Nano-structures

    Institute of Scientific and Technical Information of China (English)

    姚永德

    2004-01-01

    Fabrication of magnetic nano-structures with dots array and wires has been paid attention recently due to the application of high-density magnetic recording. In this study, we fabricated the magnetic dots array and wires through several ways that ensure the arrangement of magnetic dots and wires to be the structures we designed. Their magnetic properties are studied experimentally.

  1. Development of Magnetic Refrigerator

    Science.gov (United States)

    Ogiwara, Hiroyasu; Nakagome, Hideki; Kuriyama, Tohru

    A series of R & D of magnetic refrigerators has been done in order to realize an advanced type cryocooler for superconducting magnets of maglev trains and MRI medical system. As a result of efforts on both the magnetic refrigerator and superconducting magnets, a parasitic type magnetic refrigeration system was proposed.

  2. MRI (Magnetic Resonance Imaging)

    Science.gov (United States)

    ... and Procedures Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options ... usually given through an IV in the arm. MRI Research Programs at FDA Magnetic Resonance Imaging (MRI) ...

  3. Magnetism of Carbonados

    Science.gov (United States)

    Kletetschka, G.; Taylor, P. T.; Wasilewski, P. J.

    2000-01-01

    Origin of Carbonado is not clear. Magnetism of Carbonado comes from the surface, indicating contemporary formation of both the surface and magnetic carriers. The interior of carbonado is relatively free of magnetic phases.

  4. Magnetic Resonance Imaging

    Science.gov (United States)

    ... metallic objects from being attracted by the powerful magnet of the MR system, you will typically receive ... teeth with magnetic keepers Other implants that involve magnets Medication patch (i.e., transdermal patch) that contains ...

  5. Magnetized accretion

    Science.gov (United States)

    Heyvaerts, J.

    This lecture reviews in simple terms the general subject of large scale magnetic field coupling to plasma flows in the vicinity of accreting compact stars. The relevant astrophysical phenomenology is summarized. Disk interaction with the magnetosphere of accreting stars is first discussed, in particular the structure of the magnetopause, its stability and plasma ejection in so-called propeller systems. The physics of accretion/ejection is then considered. Acceleration and focusing mechanisms of jets from accretion disks around compact stars or black holes and the question of the self-consistency of accretion and ejection are described. By contrast, small scale MHD turbulence in disks is not discussed, neither are accretion columns near the polar caps of neutron stars or white dwarfs. The reader is only assumed to have some basic knowledge of astrophysics and of fluid mechanics and electromagnetism.

  6. Smashing magnets

    Science.gov (United States)

    Ferrier-Barbut, Igor

    2016-11-01

    Understanding or designing phases of matter relies in the first place on the knowledge at the microscopic level of the interactions taking place between the constituents. In quantum gases, a renewed interest is rising about the interaction between two dipoles, owing to its anisotropic and long-range character. In a new paper, Burdick et al (2016 New J. Phys. 18 113004) demonstrate experimentally the angular-dependence of collisions between two dysprosium atoms, an atomic species that carries a magnetic dipole moment among the largest in the periodic table. This is realized by colliding two 164Dy Bose-Einstein condensates, and the experiments are backed by a theoretical analysis to connect these results with the two-body scattering cross-section. This represents a further step on the way to the full control of dipole-interacting many-body systems.

  7. Electromechanical integrated magnetic gear

    OpenAIRE

    Xiu-hong Hao; Hong-fei Zhang; Ji-de Men

    2016-01-01

    This study proposes a new type of magnetic gear, namely, the electromechanical integrated magnetic gear, that integrates the traditional field-modulated magnetic gear, drive, and control. The topology and operating principle of the electromechanical integrated magnetic gear are described in detail in this article, and the constraints of parameter design and speed ratio of electromechanical integrated magnetic gear are presented. Moreover, magnetic field distribution is analyzed with the finit...

  8. Developing bulk exchange spring magnets

    Energy Technology Data Exchange (ETDEWEB)

    Mccall, Scott K.; Kuntz, Joshua D.

    2017-06-27

    A method of making a bulk exchange spring magnet by providing a magnetically soft material, providing a hard magnetic material, and producing a composite of said magnetically soft material and said hard magnetic material to make the bulk exchange spring magnet. The step of producing a composite of magnetically soft material and hard magnetic material is accomplished by electrophoretic deposition of the magnetically soft material and the hard magnetic material to make the bulk exchange spring magnet.

  9. Magnetic Field Calculator

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Magnetic Field Calculator will calculate the total magnetic field, including components (declination, inclination, horizontal intensity, northerly intensity,...

  10. Integrated magnetic transformer assembly

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to an integrated magnetics transformer assembly comprising a first magnetically permeable core forming a first substantially closed magnetic flux path and a second magnetically permeable core forming a second substantially closed magnetic flux path. A first input...... inductor winding is wound around a first predetermined segment of the first magnetically permeable core and a second input inductor winding is wound around a first predetermined segment of the second magnetically permeable core. The integrated magnetics transformer assembly further comprises a first output......-winding of the first output inductor winding and the first half-winding of the second output inductor winding are configured to produce aligned, i.e. in the same direction, magnetic fluxes through the first substantially closed magnetic flux path. The integrated magnetics transformer assembly is well- suited for use...

  11. Sensitive detection of Campylobacter jejuni using nanoparticles enhanced QCM sensor.

    Science.gov (United States)

    Masdor, Noor Azlina; Altintas, Zeynep; Tothill, Ibtisam E

    2016-04-15

    A quartz crystal microbalance (QCM) sensor platform was used to develop an immunosensor for the detection of food pathogen Campylobacter jejuni. Rabbit polyclonal antibodies and commercially available mouse monoclonal antibodies against C. jejuni were investigated to construct direct, sandwich and gold-nanoparticles (AuNPs) amplified sandwich assays. The performance of the QCM immunosensor developed using sandwich assay by utilising the rabbit polyclonal antibody as the capture antibody and conjugated to AuNPs as the detection antibody gave the highest sensitivity. This sensor achieved a limit of detection (LOD) of 150 colony forming unit (CFU)mL(-1) of C. jejuni in solution. The QCM sensor showed excellent sensitivity and specificity for Campylobacter detection with low cross reactivity for other foodborne pathogens such as Salmonella Typhimurium, (7%) Listeria monocytogenes (3%) and Escherichia coli (0%). The development of this biosensor would help in the sensitive detection of Campylobacter which can result in reducing pre-enrichment steps; hence, reducing assay time. This work demonstrates the potential of this technology for the development of a rapid and sensitive detection method for C. jejuni.

  12. Dynamic Response and Simulations of Nanoparticle-Enhanced Composites

    Science.gov (United States)

    2007-11-15

    variation for 1.25 wt percent (MWCNT). 129 Effect of enviromental aging on nylon 6,6 reinforced with 2.5 wt percent (MWCNT) 0 was almost negligible...high heat deflection temperature, low thermal expansion coefficient, high tensile strength and low permeation rates. A critical issue for...value of ho as in the expression of elastic energy, the proper choice of ho could be a governing issue . The thermodynamic tension has the property of

  13. Photocatalytic TiO2 nanoparticles enhanced polymer antimicrobial coating

    Science.gov (United States)

    Wei, Xiaojin; Yang, Zhendi; Tay, See Leng; Gao, Wei

    2014-01-01

    Copper (Cu) containing coatings can provide sustainable protection against microbial contamination. However, metallic Cu coatings have not been widely used due to the relatively high cost, poor corrosion resistance, and low compatibility with non-metal substrates. Titanium dioxide (TiO2) possesses antibacterial functions by its photocatalytic properties which can destroy bacteria or suppress their reproduction. TiO2 also has the function of improving the mechanical properties through particle dispersion strengthening. We have recently developed an innovative polymer based coating system containing fine particles of Cu and TiO2 nanoparticles. These polymer based coatings simultaneously display excellent antimicrobial and good mechanical properties. The results showed that the addition of TiO2 has improved the antimicrobial property under sunlight, which provides extended applications in outdoor environment. The elimination of 106 bacterial by contacting the coatings without TiO2 needs 5 h, while contacting with the Cu/TiO2- 1 wt.% TiO2 took only 2 h to kill the same amount of bacteria. The coatings also presented enhanced hardness and wear resistance after adding TiO2. The width of wear track decreased from 270 μm of the Cu-polymer coating to 206 μm of Cu/TiO2-polymer coatings with 10 wt.% TiO2. Synchrotron Infrared Microscopy was used to in-situ and in-vivo study the bacteria killing process at the molecular level. The real-time chemical images of bacterial activities showed that the bacterial cell membranes were damaged by the Cu and TiO2 containing coatings

  14. Radiative heat transfer between nanoparticles enhanced by intermediate particle

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yanhong; Wu, Jingzhi, E-mail: jzwu@live.nuc.edu.cn [Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051, Shanxi (China)

    2016-02-15

    Radiative heat transfer between two polar nanostructures at different temperatures can be enhanced by resonant tunneling of surface polaritons. Here we show that the heat transfer between two nanoparticles is strongly varied by the interactions with a third nanoparticle. By controlling the size of the third particle, the time scale of thermalization toward the thermal bath temperature can be modified over 5 orders of magnitude. This effect provides control of temperature distribution in nanoparticle aggregation and facilitates thermal management at nanoscale.

  15. Nanoparticle enhanced optical imaging and phototherapy of cancer.

    Science.gov (United States)

    Pekkanen, Allison M; DeWitt, Matthew R; Rylander, Marissa Nichole

    2014-09-01

    Nanoparticle research has seen advances in many fields, including the imaging and treatment of cancer. Specifically, nanotechnology has been investigated for its potential to be used as a tool to deliver well-tested drugs in potentially safer concentrations through both passive and active tumor targeting, while additionally providing means for a secondary therapy or imaging contrast. In particular, the use of light in conjunction with nanoparticle-based imaging and therapies has grown in popularity in recent years due to advances in utilizing light energy. In this review, we will first discuss nanoparticle platforms that can be used for optical imaging of cancer, such as fluorescence generation with quantum dots and surface-enhanced Raman scattering with plasmonic nanoparticles. We then analyze nanoparticle therapies, including photothermal therapy, photodynamic therapies, and photoacoustic therapy and their differences in exploiting light for cancer treatment. For photothermal therapies in particular, we have aggregated data on key variables in gold nanoparticle treatment protocols, such as exposure energy and nanoparticle concentration, and hope to highlight the need for normalization of variable reporting across varying experimental conditions and energy sources. We additionally discuss the potential to co-deliver chemotherapeutic drugs to the tumor using nanoparticles and how light can be harnessed for multifunctional approaches to cancer therapy. Finally, current in vitro methods of testing these therapies is discussed as well as the potential to improve on clinical translatability through 3D tissue phantoms. This review is focused on presenting, for the first time, a comprehensive comparison on a wide variety of photo based nanoparticle interactions leading to novel treatments and imaging tools from a basic science to clinical aspects and future directions.

  16. Biodegradable magnesium nanoparticle-enhanced laser hyperthermia therapy

    Directory of Open Access Journals (Sweden)

    Wang Q

    2012-08-01

    Full Text Available Qian Wang,1 Liping Xie,1 Zhizhu He,2 Derui Di,2 Jing Liu1,21Department of Biomedical Engineering, School of Medicine, Tsinghua University, 2Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing, People's Republic of ChinaBackground: Recently, nanoparticles have been demonstrated to have tremendous merit in terms of improving the treatment specificity and thermal ablation effect on tumors. However, the potential toxicity and long-term side effects caused by the introduced nanoparticles and by expelling them out of the body following surgery remain a significant challenge. Here, we propose for the first time to directly adopt magnesium nanoparticles as the heating enhancer in laser thermal ablation to avoid these problems by making full use of the perfect biodegradable properties of this specific material.Methods: To better understand the new nano “green” hyperthermia modality, we evaluated the effects of magnesium nanoparticles on the temperature transients inside the human body subject to laser interstitial heating. Further, we experimentally investigated the heating enhancement effects of magnesium nanoparticles on a group of biological samples: oil, egg white, egg yolk, in vitro pig tissues, and the in vivo hind leg of rabbit when subjected to laser irradiation.Results: Both the theoretical simulations and experimental measurements demonstrated that the target tissues injected with magnesium nanoparticles reached much higher temperatures than tissues without magnesium nanoparticles. This revealed the enhancing behavior of the new nanohyperthermia method.Conclusion: Given the unique features of magnesium nanoparticles – their complete biological safety and ability to enhance heating – which most other advanced metal nanoparticles do not possess, the use of magnesium nanoparticles in hyperthermia therapy offers an important “green” nanomedicine modality for treating tumors. This method has the potential to be used in clinics in the near future.Keywords: laser thermal therapy, heating enhancer, biodegradability, nanohyperthermia, bioheat transfer

  17. Radiative heat transfer between nanoparticles enhanced by intermediate particle

    Directory of Open Access Journals (Sweden)

    Yanhong Wang

    2016-02-01

    Full Text Available Radiative heat transfer between two polar nanostructures at different temperatures can be enhanced by resonant tunneling of surface polaritons. Here we show that the heat transfer between two nanoparticles is strongly varied by the interactions with a third nanoparticle. By controlling the size of the third particle, the time scale of thermalization toward the thermal bath temperature can be modified over 5 orders of magnitude. This effect provides control of temperature distribution in nanoparticle aggregation and facilitates thermal management at nanoscale.

  18. Gold Nanoparticles-Enhanced Proton Exchange Membrane (PEM) Fuel Cell

    Science.gov (United States)

    Li, Hongfei; Pan, Cheng; Liu, Ping; Zhu, Yimei; Adzic, Radoslav; Rafailovich, Miriam

    Proton exchange membrane fuel cells have drawn great attention and been taken as a promising alternated energy source. One of the reasons hamper the wider application of PEM fuel cell is the catalytic poison effect from the impurity of the gas flow. Haruta has predicted that gold nanoparticles that are platelet shaped and have direct contact with the metal oxide substrate to be the perfect catalysts of the CO oxidization, yet the synthesis method is difficult to apply in the Fuel Cell. In our approach, thiol-functionalized gold nanoparticles were synthesized through two-phase method developed by Brust et al. We deposit these Au particles with stepped surface directly onto the Nafion membrane in the PEM fuel cell by Langmuir-Blodgett method, resulting in over 50% enhancement of the efficiency of the fuel cell. DFT calculations were conducted to understand the theory of this kind of enhancement. The results indicated that only when the particles were in direct surface contact with the membrane, where AuNPs attached at the end of the Nafion side chains, it could reduce the energy barrier for the CO oxidation that could happen at T<300K.

  19. Sustainable Regeneration of Nanoparticle Enhanced Activated Carbon in Water

    Science.gov (United States)

    The regeneration and reuse of exhausted granular activated carbon (GAC) is an appropriate method for lowering operational and environmental costs. Advanced oxidation is a promising environmental friendly technique for GAC regeneration. The main objective of this research was to ...

  20. Silver Nanoparticle Enhanced Freestanding Thin-Film Silicon Solar Cells

    Science.gov (United States)

    Winans, Joshua David

    As the supply of fossil fuels diminishes in quantity the demand for alternative energy sources will consistently increase. Solar cells are an environmentally friendly and proven technology that suffer in sales due to a large upfront cost. In order to help facilitate the transition from fossil fuels to photovoltaics, module costs must be reduced to prices well below $1/Watt. Thin-film solar cells are more affordable because of the reduced materials costs, but lower in efficiency because less light is absorbed before passing through the cell. Silver nanoparticles placed at the front surface of the solar cell absorb and reradiate the energy of the light in ways such that more of the light ends being captured by the silicon. Silver nanoparticles can do this because they have free electron clouds that can take on the energy of an incident photon through collective action. This bulk action of the electrons is called a plasmon. This work begins by discussing the economics driving the need for reduced material use, and the pros and cons of taking this step. Next, the fundamental theory of light-matter interaction is briefly described followed by an introduction to the study of plasmonics. Following that we discuss a traditional method of silver nanoparticle formation and the initial experimental studies of their effects on the ability of thin-film silicon to absorb light. Then, Finite-Difference Time-Domain simulation software is used to simulate the effects of nanoparticle morphology and size on the scattering of light at the surface of the thin-film.

  1. Gold nanoparticle-enhanced electroporation for leukemia cell transfection.

    Science.gov (United States)

    Huang, Shuyan; Zu, Yingbo; Wang, Shengnian

    2014-01-01

    Electroporation serves as an attractive nonviral gene delivery approach for its effectiveness, operational simplicity, and no restrictions of probe or cell type. The commercial electroporation systems have been widely adopted in research and clinics with protocols usually compromising appropriate transfection efficiency and cell viability. By introducing gold nanoparticles (AuNPs), we demonstrated greatly enhanced performance of electroporation from two aspects: the highly conductive, naked AuNPs help reduce the potential drop consumed by the electroporation solution so that the majority of the applied voltage of an electric pulse is truly imposed on cells with enhanced field strength; AuNPs with targeting ligands (e.g., transferrin-AuNPs or Tf-AuNPs) are bound to the cell membrane, working as virtual microelectrodes to create pores on cells with limited opening area while from many different sites. The addition of AuNPs during electroporation therefore benefits not only quicker recovery and better survival of cells but also more efficient uptake of the subjected probes. Such enhancement was successfully confirmed on a chronic myeloid leukemia cell line (i.e., K562 cells) in both a commercial batch electroporation system and a homemade flow system with pWizGFP plasmid DNA probes. The efficiency was found to be dependent on the size, concentration, and mixing ratio of free AuNPs/Tf-AuNPs. An equivalent mixture of free AuNPs and Tf-AuNPs exhibited the best enhancement with the transfection efficiency increase of two to threefold at a minimum sacrifice of the cell viability.

  2. Gold nanoparticles enhanced electroporation for mammalian cell transfection.

    Science.gov (United States)

    Zu, Yingbo; Huang, Shuyan; Liao, Wei-Ching; Lu, Yang; Wang, Shengnian

    2014-06-01

    Electroporation figured prominently as an effective nonviral gene delivery approach for its balance on the transfection efficiency and cell viability, no restrictions of probe or cell type, and operation simplicity. The commercial electroporation systems have been widely adopted in the past two decades while still carry drawbacks associated with the high applied electric voltage, unsatisfied delivery efficiency, and/or low cell viability. By adding highly conductive gold nanoparticles (AuNPs) in electroporation solution, we demonstrated enhanced electroporation performance (i.e., better DNA delivery efficiency and higher cell viability) on mammalian cells from two different aspects: the free, naked AuNPs reduce the resistance of the electroporation solution so that the local pulse strength on cells was enhanced; targeting AuNPs (e.g., Tf-AuNPs) were brought to the cell membrane to work as virtual microelectrodes to porate cells with limited area from many different sites. The enhancement was confirmed with leukemia cells in both a commercial batch electroporation system and a home-made flow-through system using pWizGFP plasmid DNA probes. Such enhancement depends on the size, concentration, and the mixing ratio of free AuNPs/Tf-AuNPs. An equivalent mixture of free AuNPs and Tf-AuNPs exhibited the best enhancement with the transfection efficiency increased 2-3 folds at minimum sacrifice of cell viability. This new delivery concept, the combination of nanoparticles and electroporation technologies, may stimulate various in vitro and in vivo biomedical applications which rely on the efficient delivery of nucleic acids, anticancer drugs, or other therapeutic materials.

  3. Magnetic domains the analysis of magnetic microstructures

    CERN Document Server

    Hubert, Alex

    1998-01-01

    The book gives a systematic and comprehensive survey of the complete area of magnetic microstructures. It reaches from micromagnetism of nanoparticles to complex structures of extended magnetic materials. The book starts with a comprehensive evaluation of traditional and modern experimental methods for the observation of magnetic domains and continues with the treatment of important methods for the theoretical analysis of magnetic microcstructures. A survey of the necessary techniques in materials characterization is given. The book offers an observation and analysis of magnetic domains in all

  4. Magnetic hyperthermia in solid magnetic colloids

    Science.gov (United States)

    Zubarev, A. Yu.; Iskakova, L. Yu.; Abu-Bakr, A. F.

    2017-02-01

    We present results of theoretical study of magnetic hyperthermia in systems of single-domain ferromagnetic particles homogeneously distributed in a solid matrix. The heat effect is induced by linearly polarized alternating magnetic field. The effect of magnetic interaction between the particles as well as influence of orientation of the particles magnetic axes are in a focus of our consideration. Analysis shows that the interparticle interaction increases intensity of the heat production. The thermal effect in the systems with parallel orientation of the particles axes of easy magnetization is significantly higher than that in the case of random orientation of these axes.

  5. Environmental magnetism

    CERN Document Server

    Thompson, Roy

    1986-01-01

    The scientist will be forced, in the unenthusiastic words of one of my scientific colleagues, 'to slosh about in the primordial ooze known as inter-disciplinary studies'. John Passmore Man's responsibility for nature The present text has arisen from some thirteen years advances in our perception, appraisal and creative use of collaboration between the two authors. During that of order in natural systems. Out of this can come period, upwards of a dozen postgraduates in enhanced insight into processes, structures and Edinburgh, the New University of Ulster and Liver­ systems interactions on all temporal and spatial scales pool have been closely involved in exploring many of and at all integrative levels from subatomic to cosmic. the applications of magnetic measurements described In the environment, elements of order are often in the second half of the book. Much of the text is difficult to appraise and analyse, not only because of based on their work, both published and unpublished. intrinsic complexity, but ...

  6. Hoosier Magnetics

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2015-09-30

    Hoosier Magnetics proposes to replace the indirect clinker water cooling system with a cooling system that recycles heat from the hot ferrite to preheat the combustion air. This innovative process would significantly reduce the amount of natural gas required to heat the combustion air while eliminating Hoosier’s largest source of downtime. According to the Department of Energy’s Industrial Technologies Program for Energy Efficiency and Renewable Energy, process temperature is customarily used as a rough indication of where preheating air will be cost effective. Previous studies have concluded that processes operating above 1,600° F are ideal candidates for the utilization of pre-heated combustion air. Hoosier Magnetics’ operating temperatures run between 1800-2200° F making Hoosier the perfect candidate. Using preheated air at 1200° F will result in 35% fuel savings, or $298,935 annually. Additionally, the new system would have improved process reliability and result in both production efficiency increases and cost savings. This technology is NOT practiced or utilized on a wide-spread basis but could have a significant energy reduction impact in many different high heat utilizing industries in the country. While the energy savings is apparent with this theory the application and design of such a process has not been studied.

  7. Bifurcation magnetic resonance in films magnetized along hard magnetization axis

    Energy Technology Data Exchange (ETDEWEB)

    Vasilevskaya, Tatiana M., E-mail: t_vasilevs@mail.ru [Ulyanovsk State University, Leo Tolstoy 42, 432017 Ulyanovsk (Russian Federation); Sementsov, Dmitriy I.; Shutyi, Anatoliy M. [Ulyanovsk State University, Leo Tolstoy 42, 432017 Ulyanovsk (Russian Federation)

    2012-09-15

    We study low-frequency ferromagnetic resonance in a thin film magnetized along the hard magnetization axis performing an analysis of magnetization precession dynamics equations and numerical simulation. Two types of films are considered: polycrystalline uniaxial films and single-crystal films with cubic magnetic anisotropy. An additional (bifurcation) resonance initiated by the bistability, i.e. appearance of two closely spaced equilibrium magnetization states is registered. The modification of dynamic modes provoked by variation of the frequency, amplitude, and magnetic bias value of the ac field is studied. Both steady and chaotic magnetization precession modes are registered in the bifurcation resonance range. - Highlights: Black-Right-Pointing-Pointer An additional bifurcation resonance arises in a case of a thin film magnetized along HMA. Black-Right-Pointing-Pointer Bifurcation resonance occurs due to the presence of two closely spaced equilibrium magnetization states. Black-Right-Pointing-Pointer Both regular and chaotic precession modes are realized within bifurcation resonance range. Black-Right-Pointing-Pointer Appearance of dynamic bistability is typical for bifurcation resonance.

  8. A Magnetic Paradox

    Science.gov (United States)

    Arndt, Ebe

    2006-01-01

    Two recent articles in this journal described how an air core solenoid connected to an ac power source may restore the magnetization of a bar magnet with an alternating magnetic field (see Figs. 1 and 2). Although we are quite accustomed to using a constant magnetic field in an air core solenoid to remagnetize a ferromagnet, it is puzzling that we…

  9. Magnetic multilayer structure

    Energy Technology Data Exchange (ETDEWEB)

    Herget, Philipp; O' Sullivan, Eugene J.; Romankiw, Lubomyr T.; Wang, Naigang; Webb, Bucknell C.

    2017-03-21

    A mechanism is provided for an integrated laminated magnetic device. A substrate and a multilayer stack structure form the device. The multilayer stack structure includes alternating magnetic layers and diode structures formed on the substrate. Each magnetic layer in the multilayer stack structure is separated from another magnetic layer in the multilayer stack structure by a diode structure.

  10. Magnetic multilayer structure

    Science.gov (United States)

    Herget, Philipp; O'Sullivan, Eugene J.; Romankiw, Lubomyr T.; Wang, Naigang; Webb, Bucknell C.

    2016-07-05

    A mechanism is provided for an integrated laminated magnetic device. A substrate and a multilayer stack structure form the device. The multilayer stack structure includes alternating magnetic layers and diode structures formed on the substrate. Each magnetic layer in the multilayer stack structure is separated from another magnetic layer in the multilayer stack structure by a diode structure.

  11. Ferroelectricity in spiral magnets

    NARCIS (Netherlands)

    Mostovoy, M

    2006-01-01

    It was recently observed that the ferroelectrics showing the strongest sensitivity to an applied magnetic field are spiral magnets. We present a phenomenological theory of inhomogeneous ferroelectric magnets, which describes their thermodynamics and magnetic field behavior, e.g., dielectric suscepti

  12. Magnetic effects in electrochemistry

    Directory of Open Access Journals (Sweden)

    NEBOJSA D. NIKOLIC

    2005-05-01

    Full Text Available The effect of imposed magnetic fields onto the electrodeposition of magnetic (nickel and non – magnetic (copper metals was analysed. Also, magnetic properties of electrochemically obtained nanocontacts were examined. An effort to establish a possible correlation between the morphologies of the nanocontacts and the effect of the very large ballistic magnetoresistance (BMR effect was made.

  13. Fundamentals of magnetism

    CERN Document Server

    Reis, Mario

    2013-01-01

    The Fundamentals of Magnetism is a truly unique reference text, that explores the study of magnetism and magnetic behavior with a depth that no other book can provide. It covers the most detailed descriptions of the fundamentals of magnetism providing an emphasis on statistical mechanics which is absolutely critical for understanding magnetic behavior. The books covers the classical areas of basic magnetism, including Landau Theory and magnetic interactions, but features a more concise and easy-to-read style. Perfect for upper-level graduate students and industry researchers, The Fu

  14. Magnetic confinement

    Energy Technology Data Exchange (ETDEWEB)

    Batistoni, Paola; De Marco, Francesco; Pieroni, Leonardo (ed.)

    2005-07-01

    The Frascati Tokamak Upgrade (FTU) is a compact, high-magnetic-field tokamak capable of operating at density and magnetic field values similar to, or even encompassing, those of International Thermonuclear Experimental Reactor (ITER) and therefore provides a unique opportunity to explore physics issues that are directly relevant to ITER. During 2004 the experimental activities were focussed on fully exploiting the lower hybrid system (for generating and controlling the plasma current) and the electron cyclotron heating system (joint experiment with the Institute of Plasma Physics of the National Research Council, Milan). With all four gyrotrons in operation, full electron cyclotron power was achieved up to a record level of 1.5 MW. By simultaneously injecting lower hybrid waves, to tailor the plasma current radial profile, and electron cyclotron waves, to heat the plasma centre, good confinement regimes with internal transport barriers were obtained at the highest plasma density values ever achieved for this operation regime (n {approx}1.5X10{sup 20}m{sup -3}). Specific studies were devoted to optimising the coupling of lower hybrid waves to the plasma (by real-time control of the plasma position) and to generating current by electron cyclotron current drive. The new scanning CO{sub 2} interferometer (developed by the Reversed Field Experiment Consortium) for high spatial and time resolution (1 cm/50 {mu}s) density profile measurements was extensively used. The Thomson scattering diagnostic was upgraded and enabled observation of scattered signals associated with the Confinement background plasma dynamics. As for theoretical studies on the dynamics of turbulence in plasmas, the transition from Bohm-like scaling to gyro-Bohm scaling of the local plasma diffusivity was demonstrated on the basis of a generalised four wave model (joint collaboration with Princeton Plasma Physics Laboratory and the University of California at Irvine). The transition from weak to strong

  15. Ultrafast magnetization dynamics

    OpenAIRE

    Woodford, S.

    2008-01-01

    This thesis addresses ultrafast magnetization dynamics from a theoretical perspective. The manipulation of magnetization using the inverse Faraday effect has been studied, as well as magnetic relaxation processes in quantum dots. The inverse Faraday effect – the generation of a magnetic field by nonresonant, circularly polarized light – offers the possibility to control and reverse magnetization on a timescale of a few hundred femtoseconds. This is important both for the technological advant...

  16. Ultrafast Magnetization Dynamics

    OpenAIRE

    Woodford, S.

    2008-01-01

    This thesis addresses ultrafast magnetization dynamics from a theoretical perspective. The manipulation of magnetization using the inverse Faraday effect has been studied, as well as magnetic relaxation processes in quantum dots. The inverse Faraday effect – the generation of a magnetic field by nonresonant, circularly polarized light – offers the possibility to control and reverse magnetization on a timescale of a few hundred femtoseconds. This is important both for the technological advant...

  17. Permanent magnet system of alpha magnetic spectrometer

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Alpha magnetic spectrometer (AMS) is the first large magnetic spectrometer in space. Its precursor flight was completed successfully in June 1998. The key part of AMS is the permanent magnet system, which was built by the Institute of Electric Engineering, the Institute of High Energy Physics and the Chinese Academy of Launch Vehicle Technology. This system includes a permanent magnet made of high grade NdFeB and a support structure. The unique design of the permanent magnet based on the magic ring fulfills the severe requirements on the magnetic field leakage and the dipole moment for space experiments. The permanent magnet weighs about 2 tons, and provides a geometric acceptance of 0.6 m2 ·sr and an analyzing power BL2 of 0.135 T·m2. It works up to 40℃ without demagnetization. The main structure is a thin double shell, which undergoes the strong magnetic force and torque of the permanent magnet, as well as the large load during launching and landing. The permanent magnet system fulfills the requirements from AMS, and satisfies the strict safety standards of NASA.

  18. Permanent magnet system of alpha magnetic spectrometer

    Institute of Scientific and Technical Information of China (English)

    陈和生

    2000-01-01

    Alpha magnetic spectrometer (AMS) is the first large magnetic spectrometer in space. Its precursor flight was completed successfully in June 1998. The key part of AMS is the permanent magnet system, which was built by the Institute of Electric Engineering, the Institute of High Energy Physics and the Chinese Academy of Launch Vehicle Technology. This system includes a permanent magnet made of high grade NdFeB and a support structure. The unique design of the permanent magnet based on the magic ring fulfills the severe requirements on the magnetic field leakage and the dipole moment for space experiments. The permanent magnet weighs about 2 tons, and provides a geometric acceptance of 0.6 m2·sr and an analyzing power BL2 of 0.135 T·m2. It works up to 40℃ without demagnetization. The main structure is a thin double shell, which undergoes the strong magnetic force and torque of the permanent magnet, as well as the large load during launching and landing. The permanent magnet system fulfills the requirem

  19. Magnetic novae

    Science.gov (United States)

    Zemko, Polina; Orio, Marina

    2016-07-01

    We present the results of optical and X-ray observations of two quiescent novae, V2491 Cyg and V4743 Sgr. Our observations suggest the intriguing possibility of localization of hydrogen burning in magnetic novae, in which accretion is streamed to the polar caps. V2491 Cyg was observed with Suzaku more than 2 years after the outburst and V4743 Sgr was observed with XMM Newton 2 and 3.5 years after maximum. In the framework of a monitoring program of novae previously observed as super soft X-ray sources we also obtained optical spectra of V4743 Sgr with the SALT telescope 11.5 years after the eruption and of V2491 Cyg with the 6m Big Azimutal Telescope 4 and 7 years post-outburst. In order to confirm the possible white dwarf spin period of V2491 Cyg measured in the Suzaku observations we obtained photometric data using the 90cm WIYN telescope at Kitt Peak and the 1.2 m telescope in Crimea. We found that V4743 Sgr is an intermediate polar (IP) and V2491 Cyg is a strong IP candidate. Both novae show modulation of their X-ray light curves and have X-ray spectra typical of IPs. The Suzaku and XMM Newton exposures revealed that the spectra of both novae have a very soft blackbody-like component with a temperature close to that of the hydrogen burning white dwarfs in their SSS phases, but with flux by at least two orders of magnitude lower, implying a possible shrinking of emitting regions in the thin atmosphere that is heated by nuclear burning underneath it. In quiescent IPs, independently of the burning, an ultrasoft X-ray flux component originates at times in the polar regions irradiated by the accretion column, but the soft component of V4743 Sgr disappeared in 2006, indicating that the origin may be different from accretion. We suggest it may have been due to an atmospheric temperature gradient on the white dwarf surface, or to continuing localized thermonuclear burning at the bottom of the envelope, before complete turn-off. The optical spectra of V2491 Cyg and V

  20. Magnetically Damped Furnace Bitter Magnet Coil 1

    Science.gov (United States)

    Bird, M. D.

    1997-01-01

    A magnet has been built by the National High Magnetic Field Laboratory for NASA on a cost reimbursement contract. The magnet is intended to demonstrate the technology and feasibility of building a magnet for space based crystal growth. A Bitter magnet (named after Francis Bitter, its inventor) was built consisting of four split coils electrically in series and hydraulically in parallel. The coils are housed in a steel vessel to reduce the fringe field and provide some on-axis field enhancement. The steel was nickel plated and Teflon coated to minimize interaction with the water cooling system. The magnet provides 0.14 T in a 184 mm bore with 3 kW of power.

  1. Improving Staging in Bladder Cancer: The Increasing Role of Multiparametric Magnetic Resonance Imaging.

    Science.gov (United States)

    Panebianco, Valeria; Barchetti, Flavio; de Haas, Robbert J; Pearson, Rachel A; Kennish, Steven J; Giannarini, Gianluca; Catto, James W F

    2016-06-01

    In bladder cancer (BCa) patients, accurate local and regional tumor staging is required when planning treatment. Clinical understaging frequently occurs and leads to undertreatment of the disease, with a negative impact on survival. An improvement in staging accuracy could be attained by advances in imaging. Magnetic resonance imaging (MRI) is currently the best imaging technique for locoregional staging for several malignancies because of its superior soft tissue contrast resolution with the advantage of avoiding exposure to ionizing radiation. Important improvements in MRI technology have led to the introduction of multiparametric MRI (mpMRI), which combines anatomic and functional evaluation. To review the fundamentals of mpMRI in BCa and to provide a contemporary overview of the available data on the role of this emerging imaging technology. A nonsystematic literature search using the Medline and Cochrane Library databases was performed up to March 2016. Additional articles were retrieved by cross-matching references of selected articles. Only articles reporting complete data with regard to image acquisition protocols, locoregional staging, monitoring response to therapy, and detection of locoregional recurrence after primary treatment in BCa patients were selected. Standardization of acquisition and reporting protocols for bladder mpMRI is paramount. Combining anatomic and functional sequences improves the accuracy of local tumor staging compared with conventional imaging alone. Diffusion-weighted imaging may distinguish BCa type and grade. Functional sequences are capable of monitoring response to chemotherapy and radiation therapy. Diffusion-weighted imaging enhanced by lymphotropic nanoparticles showed high accuracy in pelvic lymph node staging compared with conventional cross-sectional imaging. In BCa patients, mpMRI appears a promising tool for accurate locoregional staging, predicting tumor aggressiveness and monitoring response to therapy. Further large

  2. Cosmological Magnetic Fields

    CERN Document Server

    Kunze, Kerstin E

    2013-01-01

    Magnetic fields are observed on nearly all scales in the universe, from stars and galaxies upto galaxy clusters and even beyond. The origin of cosmic magnetic fields is still an open question, however a large class of models puts its origin in the very early universe. A magnetic dynamo amplifying an initial seed magnetic field could explain the present day strength of the galactic magnetic field. However, it is still an open problem how and when this initial magnetic field was created. Observations of the cosmic microwave background (CMB) provide a window to the early universe and might therefore be able to tell us whether cosmic magnetic fields are of primordial, cosmological origin and at the same time constrain its parameters. We will give an overview of the observational evidence of large scale magnetic fields, describe generation mechanisms of primordial magnetic fields and possible imprints in the CMB.

  3. Advanced Magnetic Nanostructures

    CERN Document Server

    Sellmyer, David

    2006-01-01

    Advanced Magnetic Nanostructures is devoted to the fabrication, characterization, experimental investigation, theoretical understanding, and utilization of advanced magnetic nanostructures. Focus is on various types of 'bottom-up' and 'top-down' artificial nanostructures, as contrasted to naturally occurring magnetic nanostructures, such as iron-oxide inclusions in magnetic rocks, and to structures such as perfect thin films. Chapter 1 is an introduction into some basic concepts, such as the definitions of basic magnetic quantities. Chapters 2-4 are devoted to the theory of magnetic nanostructures, Chapter 5 deals with the characterization of the structures, and Chapters 6-10 are devoted to specific systems. Applications of advanced magnetic nanostructures are discussed in Chapters11-15 and, finally, the appendix lists and briefly discusses magnetic properties of typical starting materials. Industrial and academic researchers in magnetism and related areas such as nanotechnology, materials science, and theore...

  4. Multifunctionality in molecular magnetism.

    Science.gov (United States)

    Pinkowicz, Dawid; Czarnecki, Bernard; Reczyński, Mateusz; Arczyński, Mirosław

    2015-01-01

    Molecular magnetism draws from the fundamental ideas of structural chemistry and combines them with experimental physics resulting in one of the highest profile current topics, namely molecular materials that exhibit multifunctionality. Recent advances in the design of new generations of multifunctional molecular magnets that retain the functions of the building blocks and exhibit non-trivial magnetic properties at higher temperatures provide promising evidence that they may be useful for the future construction of nanoscale devices. This article is not a complete review but is rather an introduction into thefascinating world of multifunctional solids with magnetism as the leitmotif. We provide a subjective selection and discussion of the most inspiring examples of multifunctional molecular magnets: magnetic sponges, guest-responsive magnets, molecular magnets with ionic conductivity, photomagnets and non-centrosymmetric and chiral magnets.

  5. Human T-cell lymphotropic virus type II in Guaraní Indians, Southern Brazil Vírus linfotrópico de células T-humanas do tipo II em Índios Guaraní, Sul do Brasil

    Directory of Open Access Journals (Sweden)

    Marcio Menna-Barreto

    2005-12-01

    Full Text Available Human T-cell lymphotropic virus type II (HTLV-II is found in many New World Indian groups on the American continent. In Brazil, HTLV-II has been found among urban residents and Indians in the Amazon region, in the North. Guaraní Indians in the South of Brazil were studied for HTLV-I/II infection. Among 52 individuals, three (5.76% showed positive anti-HTLV-II antibodies (enzyme-linked immunosorbent assay and Western blot. This preliminary report is the first seroepidemiological study showing HTLV-II infection among Indians in the South of Brazil.O vírus linfotrópico de células T-humanas do tipo II (HTLV-II é identificado em muitos grupos de ameríndios. No Brasil, tem sido encontrado em indivíduos da população urbana, bem como em índios oriundos da região Amazônica. Os Índios Guaraní, do Sul do país, foram investigados para infecção por HTLV-I/II. Três indivíduos, oriundos de uma amostra de 52 índios, demonstraram sororeatividade para HTLV-II (ensaio imunoenzimático e Western blot. Este estudo preliminar foi o primeiro a identificar a presença de infecção por HTLV-II em ameríndios do Sul do Brasil.

  6. Antibody to human T-lymphotropic virus in a patient with Guillain-Barré syndrome (case report Anticorpo para o vírus linfotrópico humano T em um paciente com a síndrome de Guillain-Barré

    Directory of Open Access Journals (Sweden)

    C.M. Nakauchi

    1991-08-01

    Full Text Available Serum sample obtained from a male, 12 year old patient suffering from Guillain-Barré syndrome (GBS was positive for human T-lymphotropic virus (HTLV-I antibody by the enzyme-linked immunosorbent assay (ELISA and the Western Blot analysis (WB. Attempts to isolate enteroviruses (including poliovirus from faecal material in both tissue culture and suckling mice were unsuccessful; in addition, acute and convalescent paired serum samples did not show any evidence of recent poliovirus infection when tested against the three serotypes. Specific tests for detection of Epstein-Barr virus infection were not performed; however, the Paul-Bunnel test yielded negative results. ELISA for detection of anti-cytomegalovirus IgM was also negative. The concomitant occurrence of either adult T cell leukemia (ATL or lymphoma was not recorded in this case.Amostra de soro obtida de paciente com a síndrome de Guillain-Barré revelou-se positiva quanto à presença de anticorpos para o vírus linfotrópico humano T (HTLV-I pelo método imuno-enzimático (ELISA e a análise por "Western-Blot". Resultaram negativos os testes visando à detecção de enterovírus (incluindo poliovírus a partir de material fecal, tanto em cultura de tecidos como em camundongos recém-nascidos; exames com amostras de soro aguda e convalescente não exibiram qualquer evidência de infecção recente pelos três tipos de poliovírus. O teste de Paul-Bunnel, assim como o "ELISA" para a detecção de IgM anti-citomegalovírus resultaram negativos. Não foi registrada, no presente caso, quer a leucemia adulta de células T, quer linfomas.

  7. Manifestações reumáticas associadas ao vírus linfotrópico humano de células T do tipo I (HTLV-I Rheumatic manifestations associated with the human T-Cell lymphotropic virus type I (HTLV-I

    Directory of Open Access Journals (Sweden)

    Boris A. Cruz

    2005-04-01

    Full Text Available O vírus linfotrópico humano de células T tipo I (HTLV-I é reconhecido como agente etiológico da leucemia de células T do adulto. O HTLV-I é também relacionado a uma mielopatia crônica, que inclui agressão inflamatória (auto imune-mediada em sua patogênese. Outras síndromes auto-imunes, dentre as quais artrite reumatóide e síndrome de Sjögren são descritas em pacientes infectados. Nestes pacientes, estas condições clínicas parecem ser o resultado da interação entre o vírus como fator do ambiente e susceptibilidade do hospedeiro, levando ao funcionamento aberrante de mecanismos imuno-moduladores, proliferação celular e inflamação. O estudo dos aspectos clínicos e imunológicos das manifestações reumáticas associadas ao HTLV-I pode contribuir para o melhor entendimento das doenças auto-imunes.The Human T-Cell Lymphotropic Virus Type I is known as the etiologic agent of Adult T-Cell Leukemia. The HTLV-I is also related to a chronic myelopathy, which includes (auto immune-mediated inflammatory injury in its pathogenesis. Other autoimmune syndromes such as Rheumatoid Arthritis and Sjögren's Syndrome are reported in infected patients. In those patients, these clinical conditions seem to be the result of the interaction between the virus as an environmental agent and host susceptibility, leading to an aberrant functioning of immunomodulatory mechanisms, cellular proliferation and inflammation. The study of clinical and immunological aspects of the HTLV-I-associated rheumatic manifestations may contribute to the better understanding of the auto-immune diseases.

  8. Clinical symptoms and the odds of human T-cell lymphotropic virus type 1-associated myelopathy/ tropical spastic paraparesis (HAM/TSP) in healthy virus carriers: application of best-fit logistic regression equation based on host genotype, age, and provirus load.

    Science.gov (United States)

    Nose, Hirohisa; Saito, Mineki; Usuku, Koichiro; Sabouri, Amir H; Matsuzaki, Toshio; Kubota, Ryuji; Eiraku, Nobutaka; Furukawa, Yoshitaka; Izumo, Shuji; Arimura, Kimiyoshi; Osame, Mitsuhiro

    2006-06-01

    The authors have previously developed a logistic regression equation to predict the odds that a human T-cell lymphotropic virus type 1 (HTLV-1)-infected individual of specified genotype, age, and provirus load has HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in southern Japan. This study evaluated whether this equation is useful predictor for monitoring asymptomatic HTLV-1-seropositive carriers (HCs) in the same population. The authors genotyped 181 HCs for each HAM/TSP-associated gene (tumor necrosis factor [TNF]-alpha-863A/C, stromal cell-derived factor 1 (SDF-1) +801G/A, human leukocyte antigen [HLA]-A*02, HLA-Cw*08, HTLV-1 tax subgroup) and measured HTLV-1 provirus load in peripheral blood mononuclear cells using real-time polymerase chain reaction (PCR). Finally, the odds of HAM/TSP for each subject were calculated by using the equation and compared the results with clinical symptoms and laboratory findings. Although no clear difference was seen between the odds of HAM/TSP and either sex, family history of HAM/TSP or adult T-cell lenkemia (ATL), history of blood transfusion, it was found that brisk patellar deep tendon reflexes, which suggest latent central nervous system compromise, and flower cell-like abnormal lymphocytes, which is the morphological characteristic of ATL cells, were associated with a higher odds of HAM/TSP. The best-fit logistic regression equation may be useful for detecting subclinical abnormalities in HCs in southern Japan.

  9. CME Magnetic Structure and Magnetic Cloud Signature

    Science.gov (United States)

    Li, Yan; Luhmann, J.

    2006-06-01

    An interplanetary coronal mass ejection (ICME) is the counterpart of a coronal mass ejection by definition. However, the relationship between the magnetic structures of the CMEs and that of the situ observations of ICMEs is still quite far from clear, due to observational gaps and the state of our understanding of CMEs. Some studies suggested that the magnetic cloud (MC, a group of ICMEs with fluxrope signatures) magnetic polarity follows the solar large scale magnetic field, and others suggested it follows the local magnetic field of the CME source region. Recent studies found that the relationship is more complex. While solar cycle dependence of the magnetic signature of MCs is clearly evident, the polarity of the MCs does not reverse at the same time when the solar large scale field reverses around solar maximum, but begins to have mixed polarities, and the new polarity may only prevail at the midst of the declining phase. Interestingly, in an independent study of the magnetic topology at the CME source regions, we found a similar solar cycle dependence of the bipolar and quadrupolar topologie. In this work, the link between CMEs and ICMEs is made and the results will shed light on our understanding about the relationship between CME and ICME magnetic structures and how these structures are related to solar local and large scale magnetic fields.Acknowledgement: ATM/NSF-0451438, SRT/NASA-NNG06GE51G and CISM/NSF.

  10. Micro-Magnets

    Science.gov (United States)

    Herlach, F.; Volodin, A.; Van Haesendonck, C.

    2004-11-01

    Suggestions are made regarding the feasibility of building very small electromagnets for experimental applications. These structures would be made by lithographic techniques on a scale of microns. However, pulsed solenoid magnets with a bore on the order of a millimeter are also considered. These must be immersed in the cryogenic liquid used in the experiment, as the small bore does not allow for a separate cryostat. The magnets made by lithography could be single loops (e.g. to provide a field gradient), spirals, Helmholtz pairs, or stacks resembling a Bitter magnet. Superconducting magnets, resistive dc magnets and pulsed magnets (both non-destructive as well as self-destructing) are all considered.

  11. Tamper resistant magnetic stripes

    Science.gov (United States)

    Naylor, Richard Brian; Sharp, Donald J.

    1999-01-01

    This invention relates to a magnetic stripe comprising a medium in which magnetized particles are suspended and in which the encoded information is recorded by actual physical rotation or alignment of the previously magnetized particles within the flux reversals of the stripe which are 180.degree. opposed in their magnetic polarity. The magnetized particles are suspended in a medium which is solid, or physically rigid, at ambient temperatures but which at moderately elevated temperatures, such as 40.degree. C., is thinable to a viscosity permissive of rotation of the particles therein under applications of moderate external magnetic field strengths within acceptable time limits.

  12. Multilayered Magnetic Gelatin Membrane Scaffolds

    Science.gov (United States)

    Samal, Sangram K.; Goranov, Vitaly; Dash, Mamoni; Russo, Alessandro; Shelyakova, Tatiana; Graziosi, Patrizio; Lungaro, Lisa; Riminucci, Alberto; Uhlarz, Marc; Bañobre-López, Manuel; Rivas, Jose; Herrmannsdörfer, Thomas; Rajadas, Jayakumar; De Smedt, Stefaan; Braeckmans, Kevin; Kaplan, David L.; Dediu, V. Alek

    2016-01-01

    A versatile approach for the design and fabrication of multilayer magnetic scaffolds with tunable magnetic gradients is described. Multilayer magnetic gelatin membrane scaffolds with intrinsic magnetic gradients were designed to encapsulate magnetized bioagents under an externally applied magnetic field for use in magnetic-field-assisted tissue engineering. The temperature of the individual membranes increased up to 43.7 °C under an applied oscillating magnetic field for 70 s by magnetic hyperthermia, enabling the possibility of inducing a thermal gradient inside the final 3D multilayer magnetic scaffolds. On the basis of finite element method simulations, magnetic gelatin membranes with different concentrations of magnetic nanoparticles were assembled into 3D multilayered scaffolds. A magnetic-gradient-controlled distribution of magnetically labeled stem cells was demonstrated in vitro. This magnetic biomaterial–magnetic cell strategy can be expanded to a number of different magnetic biomaterials for various tissue engineering applications. PMID:26451743

  13. The magnetic stress tensor in magnetized matter

    CERN Document Server

    Espinosa, Olivier R; Espinosa, Olivier; Reisenegger, Andreas

    2003-01-01

    We derive the form of the magnetic stress tensor in a completely general, stationary magnetic medium, with an arbitrary magnetization field $vec M(vec r)$ and free current density $vec j(vec r)$. We start with the magnetic force density $vec f$ acting on a matter element, modelled as a collection of microscopic magnetic dipoles in addition to the free currents. We show that there is a unique tensor ${bf T}$ quadratic in the magnetic flux density $vec B(vec r)$ and the magnetic field $vec H(vec r)=vec B-4pivec M$ whose divergence is $nablacdot{bf T}=vec f$. In the limit $vec M=0$, the well-known vacuum magnetic stress tensor is recovered. However, the general form of the tensor is asymmetric, leading to a divergent angular acceleration for matter elements of vanishing size. We argue that this is not inconsistent, because it occurs only if $vec M$ and $vec B$ are not parallel, in which case the macroscopic field does indeed exert a torque on each of the microscopic dipoles, so this state is only possible if the...

  14. Magnetic Graphene Nanohole Superlattices

    CERN Document Server

    Yu, Decai; Liu, Miao; Liu, Wei; Liu, Feng

    2008-01-01

    We investigate the magnetic properties of nano-holes (NHs) patterned in graphene using first principles calculations. We show that superlattices consisting of a periodic array of NHs form a new family of 2D crystalline "bulk" magnets whose collective magnetic behavior is governed by inter-NH spin-spin interaction. They exhibit long-range magnetic order well above room temperature. Furthermore, magnetic semiconductors can be made by doping magnetic NHs into semiconducting NH superlattices. Our findings offer a new material system for fundamental studies of spin-spin interaction and magnetic ordering in low dimensions, and open up the exciting opportunities of making engineered magnetic materials for storage media and spintronics applications.

  15. Enhanced Magnetic Model 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Enhanced Magnetic Model (EMM) extends to degree and order 720, resolving magnetic anomalies down to 56 km wavelength. The higher resolution of the EMM results in...

  16. Magnetic fields in galaxies

    CERN Document Server

    Beck, Rainer

    2013-01-01

    Most of the visible matter in the Universe is ionized, so that cosmic magnetic fields are quite easy to generate and due to the lack of magnetic monopoles hard to destroy. Magnetic fields have been measured in or around practically all celestial objects, either by in-situ measurements of spacecrafts or by the electromagnetic radiation of embedded cosmic rays, gas or dust. The Earth, the Sun, solar planets, stars, pulsars, the Milky Way, nearby galaxies, more distant (radio) galaxies, quasars and even intergalactic space in clusters of galaxies have significant magnetic fields, and even larger volumes of the Universe may be permeated by "dark" magnetic fields. Information on cosmic magnetic fields has increased enormously as the result of the rapid development of observational methods, especially in radio astronomy. In the Milky Way, a wealth of magnetic phenomena was discovered, which are only partly related to objects visible in other spectral ranges. The large-scale structure of the Milky Way's magnetic fie...

  17. ISR magnet power supplies

    CERN Multimedia

    1970-01-01

    At the left, for the main magnets, the 18 kV switchgear is in the foreground and at the rear are cubicles with rectifiers and filters. At the right, rear, are rectifiers for pole face windings and auxiliary magnets.

  18. Magnetic Resonance (MR) Defecography

    Science.gov (United States)

    ... their nature and the strength of the MRI magnet. Many implanted devices will have a pamphlet explaining ... large cylinder-shaped tube surrounded by a circular magnet. You will lie on a moveable examination table ...

  19. Project Magnet 1996

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Project Magnet data include low altitude, high density individual track line surveys, high altitude vector data and regional magnetic anomaly grids.

  20. Active magnetic regenerator

    Science.gov (United States)

    Barclay, John A.; Steyert, William A.

    1982-01-01

    The disclosure is directed to an active magnetic regenerator apparatus and method. Brayton, Stirling, Ericsson, and Carnot cycles and the like may be utilized in an active magnetic regenerator to provide efficient refrigeration over relatively large temperature ranges.

  1. Electromechanical integrated magnetic gear

    Directory of Open Access Journals (Sweden)

    Xiu-hong Hao

    2016-06-01

    Full Text Available This study proposes a new type of magnetic gear, namely, the electromechanical integrated magnetic gear, that integrates the traditional field-modulated magnetic gear, drive, and control. The topology and operating principle of the electromechanical integrated magnetic gear are described in detail in this article, and the constraints of parameter design and speed ratio of electromechanical integrated magnetic gear are presented. Moreover, magnetic field distribution is analyzed with the finite element method. Subsequently, the harmonics of the magnetic field and the electromagnetic torque are calculated. The static torques on all the components are exhibited by finite element method and torque test. The effects of the design parameters on the torques and the torque densities are discussed, and the results show that electromechanical integrated magnetic gear has a high speed ratio and can generate a high torque at low speed. The maximum torques are affected by air-gap thickness and other parameters.

  2. Magnetic induction hyperthermia

    Science.gov (United States)

    Nikiforov, V. N.

    2007-09-01

    A review of physical principles and experimental data on magnetic hyperthermia are presented. The main principles of magnetic hyperthermia are considered. Results of its application in the therapy of oncology diseases are presented.

  3. Boulder Magnetic Observatory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data are vector and scalar component values of the Earth's magnetic field for 2004 recorded at the Boulder Magnetic Observatory in Colorado. Vector values are...

  4. Enhanced Magnetic Model 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Enhanced Magnetic Model (EMM) extends to degree and order 720, resolving magnetic anomalies down to 56 km wavelength. The higher resolution of the EMM results in...

  5. Magnetism basics and applications

    CERN Document Server

    Stefanita, Carmen-Gabriela

    2012-01-01

    This textbook is aimed at engineering students who are likely to come across magnetics applications in their professional practice. Whether designing lithography equipment containing ferromagnetic brushes, or detecting defects in aeronautics, some basic knowledge of 21st century magnetism is needed. From the magnetic tape on the pocket credit card to the read head in a personal computer, people run into magnetism in many products. Furthermore, in a variety of disciplines tools of the trade exploit magnetic principles, and many interdisciplinary laboratory research areas cross paths with magnetic phenomena that may seem mysterious to the untrained mind. Therefore, this course offers a broad coverage of magnetism topics encountered more often in this millenium, revealing key concepts on which many practical applications rest. Some traditional subjects in magnetism are discussed in the first half of the book, followed by areas likely to spark the curiosity of those more interested in today’s technological achi...

  6. Magnetic Field Grid Calculator

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Magnetic Field Properties Calculator will computes the estimated values of Earth's magnetic field(declination, inclination, vertical component, northerly...

  7. 壳聚糖介导增强幽门螺杆菌Lpp20 DNA疫苗黏膜免疫效果的研究%Chitosan-DNA nanoparticles enhancing the immune response of Helicobacter pylori Lpp20 DNA vaccine following the mucosal immunization

    Institute of Scientific and Technical Information of China (English)

    曹斌; 张艳; 刘志杰; 于文; 余敏君

    2011-01-01

    stimulated by corresponding antigen, the stimulation index of intranasal or oral delivery of chitosan-pcDNA3. 1 ( + )/Lpp20 nanoparticles group was significantly higher than that of pcDNA3.1( + )/Lpp20 group, CS group and PBS control group. Moreover, systemic and mucosal immune responses in mice induced by intranasal immunization were stronger than that of oral immunization. Conclusion Chitosan nanoparticles enhanced the immune response of pcDNA3.1 ( + )/Lpp20 DNA vaccine by intranasal or oral administration in BALB/c mice. Compared to oral administration, intranasal delivery of chitosan-pcDNA3.1 ( + )/Lpp20 DNA nanoparticles could induce stronger cellular and humoral immune responses in BALB/c mice.

  8. Axial Halbach Magnetic Bearings

    Science.gov (United States)

    Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

    2008-01-01

    Axial Halbach magnetic bearings have been investigated as part of an effort to develop increasingly reliable noncontact bearings for future high-speed rotary machines that may be used in such applications as aircraft, industrial, and land-vehicle power systems and in some medical and scientific instrumentation systems. Axial Halbach magnetic bearings are passive in the sense that unlike most other magnetic bearings that have been developed in recent years, they effect stable magnetic levitation without need for complex active control.

  9. The Earth's Magnetic Field

    OpenAIRE

    Edda Lína Gunnarsdóttir 1988

    2012-01-01

    The Earth's magnetic field is essential for life on Earth, as we know it, to exist. It forms a magnetic shield around the planet, protecting it from high energy particles and radiation from the Sun, which can cause damage to life, power systems, orbiting satellites, astronauts and spacecrafts. This report contains a general overview of the Earth's magnetic field. The different sources that contribute to the total magnetic field are presented and the diverse variations in the field are describ...

  10. Magnetic actuators and sensors

    CERN Document Server

    Brauer, John R

    2014-01-01

    An accessible, comprehensive guide on magnetic actuators and sensors, this fully updated second edition of Magnetic Actuators and Sensors includes the latest advances, numerous worked calculations, illustrations, and real-life applications. Covering magnetics, actuators, sensors, and systems, with updates of new technologies and techniques, this exemplary learning tool emphasizes computer-aided design techniques, especially magnetic finite element analysis, commonly used by today's engineers. Detailed calculations, numerous illustrations, and discussions of discrepancies make this text an inva

  11. Magnetic cluster excitations

    Science.gov (United States)

    Furrer, Albert; Waldmann, Oliver

    2013-01-01

    Magnetic clusters, i.e., assemblies of a finite number (between two or three and several hundred) of interacting spin centers which are magnetically decoupled from their environment, can be found in many materials ranging from inorganic compounds and magnetic molecules to artificial metal structures formed on surfaces and metalloproteins. Their magnetic excitation spectra are determined by the nature of the spin centers and of the magnetic interactions, and the particular arrangement of the mutual interaction paths between the spin centers. Small clusters of up to four magnetic ions are ideal model systems in which to examine the fundamental magnetic interactions, which are usually dominated by Heisenberg exchange, but often complemented by anisotropic and/or higher-order interactions. In large magnetic clusters, which may potentially deal with a dozen or more spin centers, there is the possibility of novel many-body quantum states and quantum phenomena. In this review the necessary theoretical concepts and experimental techniques to study the magnetic cluster excitations and the resulting characteristic magnetic properties are introduced, followed by examples of small clusters, demonstrating the enormous amount of detailed physical information that can be retrieved. The current understanding of the excitations and their physical interpretation in the molecular nanomagnets which represent large magnetic clusters is then presented, with a section devoted to the subclass of single-molecule magnets, distinguished by displaying quantum tunneling of the magnetization. Finally, there is a summary of some quantum many-body states which evolve in magnetic insulators characterized by built-in or field-induced magnetic clusters. The review concludes by addressing future perspectives in the field of magnetic cluster excitations.

  12. Magnetic fusion technology

    CERN Document Server

    Dolan, Thomas J

    2014-01-01

    Magnetic Fusion Technology describes the technologies that are required for successful development of nuclear fusion power plants using strong magnetic fields. These technologies include: ? magnet systems, ? plasma heating systems, ? control systems, ? energy conversion systems, ? advanced materials development, ? vacuum systems, ? cryogenic systems, ? plasma diagnostics, ? safety systems, and ? power plant design studies. Magnetic Fusion Technology will be useful to students and to specialists working in energy research.

  13. Rotating superconductor magnet for producing rotating lobed magnetic field lines

    Science.gov (United States)

    Hilal, Sadek K.; Sampson, William B.; Leonard, Edward F.

    1978-01-01

    This invention provides a rotating superconductor magnet for producing a rotating lobed magnetic field, comprising a cryostat; a superconducting magnet in the cryostat having a collar for producing a lobed magnetic field having oppositely directed adjacent field lines; rotatable support means for selectively rotating the superconductor magnet; and means for energizing the superconductor magnet.

  14. Common Magnets, Unexpected Polarities

    Science.gov (United States)

    Olson, Mark

    2013-01-01

    In this paper, I discuss a "misconception" in magnetism so simple and pervasive as to be typically unnoticed. That magnets have poles might be considered one of the more straightforward notions in introductory physics. However, the magnets common to students' experiences are likely different from those presented in educational…

  15. Iron dominated magnets

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, G.E.

    1985-07-01

    These two lectures on iron dominated magnets are meant for the student of accelerator science and contain general treatments of the subjects design and construction. The material is arranged in the categories: General Concepts and Cost Considerations, Profile Configuration and Harmonics, Magnetic Measurements, a few examples of ''special magnets'' and Materials and Practices. Extensive literature is provided.

  16. Magnetism in meteorites

    Science.gov (United States)

    Herndon, J. M.; Rowe, M. W.

    1974-01-01

    An overview is presented of magnetism in meteorites. A glossary of magnetism terminology followed by discussion of the various techniques used for magnetism studies in meteorites are included. The generalized results from use of these techniques by workers in the field are described. A brief critical analysis is offered.

  17. Nanochemistry and magnetism

    Science.gov (United States)

    Buchachenko, A. L.

    2009-10-01

    An analysis of magnetism of nanochemical systems opens up new ways to creating ferromagnets from diamagnetic substances and new principles for constructing molecular ferromagnets, hybrid magnetic materials, and monomolecular magnets on the basis of high-spin molecules and complexes. Their use in spin computing is considered.

  18. The Juno Magnetic Field Investigation

    DEFF Research Database (Denmark)

    Connerney, J. E. P.; Benn, Mathias; Bjarnø, Jonas Bækby

    2017-01-01

    The Juno Magnetic Field investigation (MAG) characterizes Jupiter’s planetary magnetic field and magnetosphere, providing the first globally distributed and proximate measurements of the magnetic field of Jupiter. The magnetic field instrumentation consists of two independent magnetometer sensor ...

  19. Magnetic hyperthermia with hard-magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kashevsky, Bronislav E., E-mail: bekas@itmo.by [A.V Luikov Heat and Mass Transfer Institute, Belarus Academy of Sciences, P. Brovka str. 15, Minsk 220072 (Belarus); Kashevsky, Sergey B.; Korenkov, Victor S. [A.V Luikov Heat and Mass Transfer Institute, Belarus Academy of Sciences, P. Brovka str. 15, Minsk 220072 (Belarus); Istomin, Yuri P. [N. N. Alexandrov National Cancer Center of Belarus, Lesnoy-2, Minsk 223040 (Belarus); Terpinskaya, Tatyana I.; Ulashchik, Vladimir S. [Institute of Physiology, Belarus Academy of Sciences, Akademicheskaya str. 28, Minsk 220072 (Belarus)

    2015-04-15

    Recent clinical trials of magnetic hyperthermia have proved, and even hardened, the Ankinson-Brezovich restriction as upon magnetic field conditions applicable to any site of human body. Subject to this restriction, which is harshly violated in numerous laboratory and small animal studies, magnetic hyperthermia can relay on rather moderate heat source, so that optimization of the whole hyperthermia system remains, after all, the basic problem predetermining its clinical perspectives. We present short account of our complex (theoretical, laboratory and small animal) studies to demonstrate that such perspectives should be related with the hyperthermia system based on hard-magnetic (Stoner–Wohlfarth type) nanoparticles and strong low-frequency fields rather than with superparamagnetic (Brownian or Neél) nanoparticles and weak high-frequency fields. This conclusion is backed by an analytical evaluation of the maximum absorption rates possible under the field restriction in the ideal hard-magnetic (Stoner–Wohlarth) and the ideal superparamagnetic (single relaxation time) systems, by theoretical and experimental studies of the dynamic magnetic hysteresis in suspensions of movable hard-magnetic particles, by producing nanoparticles with adjusted coercivity and suspensions of such particles capable of effective energy absorption and intratumoral penetration, and finally, by successful treatment of a mice model tumor under field conditions acceptable for whole human body. - Highlights: • Hard-magnetic nanoparticles are shown superior for hyperthetmia to superparamagnetic. • Optimal system parameters are found from magnetic reversal model in movable particle. • Penetrating suspension of HM particles with aggregation-independent SAR is developed. • For the first time, mice with tumors are healed in AC field acceptable for human body.

  20. A Novel DNA Nanosensor Based on CdSe/ZnS Quantum Dots and Synthesized Fe3O4 Magnetic Nanoparticles

    Directory of Open Access Journals (Sweden)

    Roozbeh Hushiarian

    2014-04-01

    Full Text Available Although nanoparticle-enhanced biosensors have been extensively researched, few studies have systematically characterized the roles of nanoparticles in enhancing biosensor functionality. This paper describes a successful new method in which DNA binds directly to iron oxide nanoparticles for use in an optical biosensor. A wide variety of nanoparticles with different properties have found broad application in biosensors because their small physical size presents unique chemical, physical, and electronic properties that are different from those of bulk materials. Of all nanoparticles, magnetic nanoparticles are proving to be a versatile tool, an excellent case in point being in DNA bioassays, where magnetic nanoparticles are often used for optimization of the hybridization and separation of target DNA. A critical step in the successful construction of a DNA biosensor is the efficient attachment of biomolecules to the surface of magnetic nanoparticles. To date, most methods of synthesizing these nanoparticles have led to the formation of hydrophobic particles that require additional surface modifications. As a result, the surface to volume ratio decreases and nonspecific bindings may occur so that the sensitivity and efficiency of the device deteriorates. A new method of large-scale synthesis of iron oxide (Fe3O4 nanoparticles which results in the magnetite particles being in aqueous phase, was employed in this study. Small modifications were applied to design an optical DNA nanosensor based on sandwich hybridization. Characterization of the synthesized particles was carried out using a variety of techniques and CdSe/ZnS core-shell quantum dots were used as the reporter markers in a spectrofluorophotometer. We showed conclusively that DNA binds to the surface of ironoxide nanoparticles without further surface modifications and that these magnetic nanoparticles can be efficiently utilized as biomolecule carriers in biosensing devices.

  1. 3-Aminopropylsilane-modified iron oxide nanoparticles for contrast-enhanced magnetic resonance imaging of liver lesions induced by Opisthorchis felineus

    Science.gov (United States)

    Demin, Alexander M; Pershina, Alexandra G; Ivanov, Vladimir V; Nevskaya, Kseniya V; Shevelev, Oleg B; Minin, Artyom S; Byzov, Iliya V; Sazonov, Alexey E; Krasnov, Victor P; Ogorodova, Ludmila M

    2016-01-01

    Purpose Liver fluke causes severe liver damage in an infected human. However, the infection often remains neglected due to the lack of pathognomonic signs. Nanoparticle-enhanced magnetic resonance imaging (MRI) offers a promising technique for detecting liver lesions induced by parasites. Materials and methods Surface modification of iron oxide nanoparticles produced by coprecipitation from a solution of Fe3+ and Fe2+ salts using 3-aminopropylsilane (APS) was carried out. The APS-modified nanoparticles were characterized by transmission electron microscopy, fourier transform infrared spectroscopy, and thermogravimetric analysis. Magnetic resonance properties of MNPs were investigated in vitro and in vivo. Results The amount of APS grafted on the surface of nanoparticles (0.60±0.06 mmol g−1) was calculated based on elemental analysis and infrared spectroscopy data. According to transmission electron microscopy data, there were no essential changes in the structure of nanoparticles during the modification. The APS-modified nanoparticles exhibit high magnetic properties; the calculated relaxivity r2 was 271 mmol−1 s−1. To obtain suspension with optimal hydrodynamic characteristics, amino groups on the surface of nanoparticles were converted into an ionic form with HCl. Cellular uptake of modified nanoparticles by rat hepatoma cells and human monocytes in vitro was 74.1±4.5 and 10.0±3.7 pg [Fe] per cell, respectively. Low cytotoxicity of the nanoparticles was confirmed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and Annexin V/7-aminoactinomycin D flow cytometry assays. For the first time, magnetic nanoparticles were applied for contrast-enhanced MRI of liver lesions induced by Opisthorchis felineus. Conclusion The synthesized APS-modified iron oxide nanoparticles showed high efficiency as an MRI contrast agent for the evaluation of opisthorchiasis-related liver damage. PMID:27660439

  2. Permanent-Magnet Meissner Bearing

    Science.gov (United States)

    Robertson, Glen A.

    1994-01-01

    Permanent-magnet meissner bearing features inherently stable, self-centering conical configuration. Bearing made stiffer or less stiff by selection of magnets, springs, and spring adjustments. Cylindrical permanent magnets with axial magnetization stacked coaxially on rotor with alternating polarity. Typically, rare-earth magnets used. Magnets machined and fitted together to form conical outer surface.

  3. Magnetism: a supramolecular function

    Energy Technology Data Exchange (ETDEWEB)

    Decurtins, S.; Pellaux, R.; Schmalle, H.W. [Zurich Univ., Inst. fuer Anorganische Chemie, Zurich (Switzerland)

    1996-11-01

    The field of molecule-based magnetism has developed tremendously in the last few years. Two different extended molecular - hence supramolecular -systems are presented. The Prussian-blue analogues show some of the highest magnetic ordering temperature of any class of molecular magnets, T{sub c} = 315 K, whereas the class of transition-metal oxalate-bridged compounds exhibits a diversity of magnetic phenomena. Especially for the latter compounds, the elastic neutron scattering technique has successfully been proven to trace the magnetic structure of these supramolecular and chiral compounds. (author) 18 figs., 25 refs.

  4. Switchable molecular magnets.

    Science.gov (United States)

    Sato, Osamu

    2012-01-01

    Various molecular magnetic compounds whose magnetic properties can be controlled by external stimuli have been developed, including electrochemically, photochemically, and chemically tunable bulk magnets as well as a phototunable antiferromagnetic phase of single chain magnet. In addition, we present tunable paramagnetic mononuclear complexes ranging from spin crossover complexes and valence tautomeric complexes to Co complexes in which orbital angular momentum can be switched. Furthermore, we recently developed several switchable clusters and one-dimensional coordination polymers. The switching of magnetic properties can be achieved by modulating metals, ligands, and molecules/ions in the second sphere of the complexes.

  5. Magnetic nanocomposite sensor

    KAUST Repository

    Alfadhel, Ahmed

    2016-05-06

    A magnetic nanocomposite device is described herein for a wide range of sensing applications. The device utilizes the permanent magnetic behavior of the nanowires to allow operation without the application of an additional magnetic field to magnetize the nanowires, which simplifies miniaturization and integration into microsystems. In5 addition, the nanocomposite benefits from the high elasticity and easy patterning of the polymer-based material, leading to a corrosion-resistant, flexible material that can be used to realize extreme sensitivity. In combination with magnetic sensor elements patterned underneath the nanocomposite, the nanocomposite device realizes highly sensitive and power efficient flexible artificial cilia sensors for flow measurement or tactile sensing.

  6. Magnetism and metallurgy of soft magnetic materials

    CERN Document Server

    Chen, Chih-Wen

    2011-01-01

    Soft magnetic materials are economically and technologically the most important of all magnetic materials. In particular, the development of new materials and novel applications for the computer and telecommunications industries during the past few decades has immensely broadened the scope and altered the nature of soft magnetic materials. In addition to metallic substances, nonmetallic compounds and amorphous thin films are coming increasingly important. This thorough, well-organized volume - on of the most comprehensive treatments available - offers a coherent, logical presentation of the p

  7. Magnetic volumetric hologram memory with magnetic garnet.

    Science.gov (United States)

    Nakamura, Yuichi; Takagi, Hiroyuki; Lim, Pang Boey; Inoue, Mitsuteru

    2014-06-30

    Holographic memory is a promising next-generation optical memory that has a higher recording density and a higher transfer rate than other types of memory. In holographic memory, magnetic garnet films can serve as rewritable holographic memory media by use of magneto-optical effect. We have now demonstrated that a magnetic hologram can be recorded volumetrically in a ferromagnetic garnet film and that the signal image can be reconstructed from it for the first time. In addition, multiplicity of the magnetic hologram was also confirmed; the image could be reconstructed from a spot overlapped by other spots.

  8. Molecule-based magnets

    Indian Academy of Sciences (India)

    J V Yakhmi

    2009-06-01

    The conventional magnetic materials used in current technology, such as, Fe, Fe2O3, Cr2O3, SmCo5, Nd2Fe14B etc are all atom-based, and their preparation/processing require high temperature routes. Employing self-assembly methods, it is possible to engineer a bulk molecular material with long-range magnetic order, mainly because one can play with the weak intermolecular interactions. Since the first successful synthesis of molecular magnets in 1986, a large variety of them have been synthesized, which can be categorized on the basis of the chemical nature of the magnetic units involved: organic-, metal-based systems, heterobimetallic assemblies, or mixed organic–inorganic systems. The design of molecule-based magnets has also been extended to the design of poly-functional molecular magnets, such as those exhibiting second-order optical nonlinearity, liquid crystallinity, or chirality simultaneously with long-range magnetic order. Solubility, low density and biocompatibility are attractive features of molecular magnets. Being weakly coloured, unlike their opaque classical magnet ‘cousins’ listed above, possibilities of photomagnetic switching exist. Persistent efforts also continue to design the ever-elusive polymer magnets towards applications in industry. While providing a brief overview of the field of molecular magnetism, this article highlights some recent developments in it, with emphasis on a few studies from the author’s own lab.

  9. Magnetically responsive enzyme powders

    Energy Technology Data Exchange (ETDEWEB)

    Pospiskova, Kristyna, E-mail: kristyna.pospiskova@upol.cz [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Safarik, Ivo, E-mail: ivosaf@yahoo.com [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 11, 783 71 Olomouc (Czech Republic); Department of Nanobiotechnology, Institute of Nanobiology and Structural Biology of GCRC, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic)

    2015-04-15

    Powdered enzymes were transformed into their insoluble magnetic derivatives retaining their catalytic activity. Enzyme powders (e.g., trypsin and lipase) were suspended in various liquid media not allowing their solubilization (e.g., saturated ammonium sulfate and highly concentrated polyethylene glycol solutions, ethanol, methanol, 2-propanol) and subsequently cross-linked with glutaraldehyde. Magnetic modification was successfully performed at low temperature in a freezer (−20 °C) using magnetic iron oxides nano- and microparticles prepared by microwave-assisted synthesis from ferrous sulfate. Magnetized cross-linked enzyme powders were stable at least for two months in water suspension without leakage of fixed magnetic particles. Operational stability of magnetically responsive enzymes during eight repeated reaction cycles was generally without loss of enzyme activity. Separation of magnetically modified cross-linked powdered enzymes from reaction mixtures was significantly simplified due to their magnetic properties. - Highlights: • Cross-linked enzyme powders were prepared in various liquid media. • Insoluble enzymes were magnetized using iron oxides particles. • Magnetic iron oxides particles were prepared by microwave-assisted synthesis. • Magnetic modification was performed under low (freezing) temperature. • Cross-linked powdered trypsin and lipase can be used repeatedly for reaction.

  10. Tunneling magnetic force microscopy

    Science.gov (United States)

    Burke, Edward R.; Gomez, Romel D.; Adly, Amr A.; Mayergoyz, Isaak D.

    1993-01-01

    We have developed a powerful new tool for studying the magnetic patterns on magnetic recording media. This was accomplished by modifying a conventional scanning tunneling microscope. The fine-wire probe that is used to image surface topography was replaced with a flexible magnetic probe. Images obtained with these probes reveal both the surface topography and the magnetic structure. We have made a thorough theoretical analysis of the interaction between the probe and the magnetic fields emanating from a typical recorded surface. Quantitative data about the constituent magnetic fields can then be obtained. We have employed these techniques in studies of two of the most important issues of magnetic record: data overwrite and maximizing data-density. These studies have shown: (1) overwritten data can be retrieved under certain conditions; and (2) improvements in data-density will require new magnetic materials. In the course of these studies we have developed new techniques to analyze magnetic fields of recorded media. These studies are both theoretical and experimental and combined with the use of our magnetic force scanning tunneling microscope should lead to further breakthroughs in the field of magnetic recording.

  11. Magnetically recoverable nanocatalysts

    KAUST Repository

    Polshettiwar, Vivek

    2011-05-11

    A broad overview on magnetically recoverable nanocatalysts is presented and the use of magnetic nanomaterials as catalysts is discussed. Magnetic materials are used as organocatalysts and their applications range to challenging reactions, such as hydroformylation and olefin metathesis. Magnetic nanomaterials are also being used in environmental applications, such as for photo- and biocatalysis and for the adsorption and removal of pollutants from air and water. These materials show great promise as enantioselective catalysts, which are used extensively for the synthesis of medicines, drugs, and other bioactive molecules. By functionalizing these materials using chiral ligands, a series of chiral nanocatalysts can be designed, offering great potential to reuse these otherwise expensive catalyst systems. Characterization of magnetic catalysts is often a challenging task, and NMR characterization of these catalysts is difficult because the magnetic nature of the materials interferes with the magnetic field of the spectrometer.

  12. Magnetism in lanthanide superlattices

    DEFF Research Database (Denmark)

    Goff, J.P.; Sarthour, R.S.; McMorrow, D.F.

    2000-01-01

    Neutron diffraction studies of heavy rare-earth superlattices have revealed the stabilization of novel magnetic phases chat are not present in bulk materials. The most striking result is the propagation of the magnetic ordering through nonmagnetic spacer materials. Here we describe some recent X......-ray magnetic resonant scattering studies of light rare-earth superlattices, which illuminate the mechanism of interlayer coupling, and provide access to different areas of Physics. such as the interplay between superconductivity and magnetism. Magnetic X-ray diffraction is found to be particularly well suited...... to the study of the modulated magnetic structures in superlattices, and provides unique information on the conduction-electron spin-density wave responsible for the propagation of magnetic order. (C) 2000 Elsevier Science B.V. All rights reserved....

  13. Superconducting pulsed magnets

    CERN Document Server

    CERN. Geneva

    2006-01-01

    Lecture 1. Introduction to Superconducting Materials Type 1,2 and high temperature superconductors; their critical temperature, field & current density. Persistent screening currents and the critical state model. Lecture 2. Magnetization and AC Loss How screening currents cause irreversible magnetization and hysteresis loops. Field errors caused by screening currents. Flux jumping. The general formulation of ac loss in terms of magnetization. AC losses caused by screening currents. Lecture 3. Twisted Wires and Cables Filamentary composite wires and the losses caused by coupling currents between filaments, the need for twisting. Why we need cables and how the coupling currents in cables contribute more ac loss. Field errors caused by coupling currents. Lecture 4. AC Losses in Magnets, Cooling and Measurement Summary of all loss mechanisms and calculation of total losses in the magnet. The need for cooling to minimize temperature rise in a magnet. Measuring ac losses in wires and in magnets. Lecture 5. Stab...

  14. Superconducting bulk magnets for magnetic levitation systems

    Science.gov (United States)

    Fujimoto, H.; Kamijo, H.

    2000-06-01

    The major applications of high-temperature superconductors have mostly been confined to products in the form of wires and thin films. However, recent developments show that rare-earth REBa 2Cu 3O 7- x and light rare-earth LREBa 2Cu 3O 7- x superconductors prepared by melt processes have a high critical-current density at 77 K and high magnetic fields. These superconductors will promote the application of bulk high-temperature superconductors in high magnetic fields; the superconducting bulk magnet for the Maglev train is one possible application. We investigated the possibility of using bulk magnets in the Maglev system, and examined flux-trapping characteristics of multi-superconducting bulks arranged in array.

  15. Active Magnetic Bearings – Magnetic Forces

    DEFF Research Database (Denmark)

    Kjølhede, Klaus

    2006-01-01

    Parameter identification procedures and model validation are major steps towards intelligent machines supported by active magnetic bearings (AMB). The ability of measuring the electromagnetic bearing forces, or deriving them from measuring the magnetic flux, strongly contributes to the model...... validation and leads to novel approaches in identifying crucial rotor parameters. This is the main focus of this paper, where an intelligent AMB is being developed with the aim of aiding the accurate identification of damping and stiffness coefficients of journal bearings and seals. The main contribution...... of the magnetic forces are led by using different experimental tests: (I) by using hall sensors mounted directly on the poles (precise measurements of the magnetic flux) and by an auxiliary system, composed of strain gages and flexible beams attached to the rotor; (II) by measuring the input current and bearing...

  16. Magnetization arrangement of hard magnetic phases and mechanism of magnetization and reversal magnetization of nano-composite magnets

    Institute of Scientific and Technical Information of China (English)

    LIU Xin-cai; XIE Ren; PAN Jing

    2009-01-01

    During the process of directional solidification, laser remelting/solidification in the layer on sintered magnets, die-upsetting of cast magnets, or die-upsetting of nano-composites, the arrangements of the easy-magnetization-axes of the hard magnetic phases (Nd_2Fe_(14)B, SmCo_5 or Sm_2Co_(17) type) in their designed directions have been studied. In Fe-Pt nano-composite magnets, attempts have been taken to promote phase transformation from disordered, soft magnetic A1 to ordered, hard magnetic L_(10) FePt phase at reduced temperatures. The dependence of the magnetization and reversal magnetization processes on the microstructures, involving the morphology and three critical sizes of particles of the FePt nano-composite magnets, are summarized. With the decrease of the nominal thickness of the anisotropic FePt film epitaxially grown on the single crystal MgO (001) substrate, the reversal magnetization process firstly changes from full domain wall displacement to partial magnetic wall pinning related to the morphology change, where the coercive force increases abruptly. The reversal magnetization process secondly changes from magnetic wall pinning to incoherent magnetization rotation associated with the particles being below the first critical size at which multi-domain particles turn into single domain ones, where the coercive force is still increased. And the reversal magnetization mode thirdly changes from incoherent to coherent rotation referred to the second critical size, where the increase of the coercive force keeps on. However, when the particle size decreases to approach the third critical size where the particles turn into the supperparamagnetic state, the coercive force begins to decrease due to the interplay of the size effect and the incomplete ordering induced by the size effect. Meanwhile, due to the size effect, Curie temperature of the ultra-small FePt particles reduces.

  17. Magnetic Excitations and Magnetic Ordering in Praseodymium

    DEFF Research Database (Denmark)

    Houmann, Jens Christian Gylden; Chapellier, M.; Mackintosh, A. R.;

    1975-01-01

    The dispersion relations for magnetic excitons propagating on the hexagonal sites of double-hcp Pr provide clear evidence for a pronounced anisotropy in the exchange. The energy of the excitations decreases rapidly as the temperature is lowered, but becomes almost constant below about 7 K......, in agreement with a random-phase-approximation calculation. No evidence of magnetic ordering has been observed above 0.4 K, although the exchange is close to the critical value necessary for an antiferromagnetic state....

  18. Magnetic-seeding filtration

    Energy Technology Data Exchange (ETDEWEB)

    DePaoli, D.W.; Tsouris, C. [Oak Ridge National Lab., TN (United States); Yiacoumi, Sotira

    1997-10-01

    Magnetic-seeding filtration is a technology under development for the enhanced removal of magnetic and non-magnetic particulates from liquids. This process involves the addition of a small amount of magnetic seed particles (such as naturally occurring iron oxide) to a waste suspension, followed by treatment with a magnetic filter. Non-magnetic and weakly magnetic particles are made to undergo nonhomogeneous flocculation with the seed particles, forming flocs of high magnetic susceptibility that are readily removed by a conventional high-gradient magnetic filter. This technology is applicable to a wide range of liquid wastes, including groundwater, process waters, and tank supernatants. Magnetic-seeding filtration may be used in several aspects of treatment, such as (1) removal of solids, particularly those in the colloidal size range that are difficult to remove by conventional means; (2) removal of contaminants by precipitation processes; and (3) removal of contaminants by sorption processes. Waste stream characteristics for which the technology may be applicable include (1) particle sizes ranging from relatively coarse (several microns) to colloidal particles, (2) high or low radiation levels, (3) broad-ranging flow rates, (4) low to moderate solids concentration, (5) cases requiring high decontamination factors, and (6) aqueous or non-aqueous liquids. At this point, the technology is at the bench-scale stage of development; laboratory studies and fundamental modeling are currently being employed to determine the capabilities of the process.

  19. Magnetism in Medicine

    Science.gov (United States)

    Schenck, John

    2000-03-01

    For centuries physicians, scientists and others have postulated an important role, either as a cause of disease or as a mode of therapy, for magnetism in medicine. Although there is a straightforward role in the removal of magnetic foreign bodies, the majority of the proposed magnetic applications have been controversial and have often been attributed by mainstream practitioners to fraud, quackery or self-deception. Calculations indicate that many of the proposed methods of action, e.g., the field-induced alignment of water molecules or alterations in blood flow, are of negligible magnitude. Nonetheless, even at the present time, the use of small surface magnets (magnetotherapy) to treat arthritis and similar diseases is a widespread form of folk medicine and is said to involve sales of approximately one billion dollars per year. Another medical application of magnetism associated with Mesmer and others (eventually known as animal magnetism) has been discredited, but has had a culturally significant role in the development of hypnotism and as one of the sources of modern psychotherapy. Over the last two decades, in marked contrast to previous applications of magnetism to medicine, magnetic resonance imaging or MRI, has become firmly established as a clinical diagnostic tool. MRI permits the non-invasive study of subtle biological processes in intact, living organisms and approximately 150,000,000 diagnostic studies have been performed since its clinical introduction in the early 1980s. The dramatically swift and widespread acceptance of MRI was made possible by scientific and engineering advances - including nuclear magnetic resonance, computer technology and whole-body-sized, high field superconducting magnets - in the decades following World War Two. Although presently used much less than MRI, additional applications, including nerve and muscle stimulation by pulsed magnetic fields, the use of magnetic forces to guide surgical instruments, and imaging utilizing

  20. Lesões dermatológicas em pacientes infectados pelo vírus linfotrópico humano de células T do tipo 1 (HTLV-1 Dermatologic lesions in patients infected with the human T-cell lymphotropic vírus type 1 (HTLV-1

    Directory of Open Access Journals (Sweden)

    Vandack Nobre

    2005-02-01

    Full Text Available O vírus linfotrópico humano de células T do tipo 1 (HTLV-1 é o primeiro retrovírus isolado do ser humano. Descreveu-se, em pouco tempo, o seu papel etiológico em algumas doenças, com destaque para a leucemia/linfoma de células T do adulto (ATLL, a mielopatia associada ao HTLV-1/paraparesia espástica tropical (HAM/TSP e a uveíte associada ao HTLV-1 (HAU. Na década de 90, o HTLV-1 foi associado a eczema grave da infância, conhecido como dermatite infecciosa (DI. Desde então, diversos outros tipos de lesões cutâneas têm sido observados em pacientes infectados pelo HTLV-1, em especial, nos doentes de HAM/TSP ou de ATLL. Porém, mesmo portadores assintomáticos do vírus apresentam doenças dermatológicas. Excetuando-se a dermatite infecciosa, não há lesão da pele específica da infecção pelo HTLV-1. Aqui, os autores apresentam as principais lesões dermatológicas descritas em pacientes infectados pelo HTLV-1, destacando o valor epidemiológico e clínico desses achados.Human T-cell Lymphotropic vírus type I (HTLV-1 was the first human retrovírus described. Some time after its discovery a group of diseases were related to this vírus, such as, adult T-cell leukemia lymphoma (ATLL, HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP and HTLV-1 associated uveitis (HAU. In the nineties, HTLV-1 was associated to a severe eczema of children, called infective dermatitis (ID. Since then, several other skin manifestations have been observed in HTLV-1-infected individuals, particularly in patients with ATLL or HAM/TSP. However, according to some reports, dermatologic lesions are also common in asymptomatic HTLV-1 carriers. Besides ID, all other skin lesions reported are nonspecific. The aim of this review is to outline the dermatologic manifestations reported in HTLV-1 infected patients, emphasizing the clinical and epidemiological value of these findings.

  1. Optimally segmented magnetic structures

    DEFF Research Database (Denmark)

    Insinga, Andrea Roberto; Bahl, Christian; Bjørk, Rasmus;

    ], or are applicable only to analytically solvable geometries[4]. In addition, some questions remained fundamentally unanswered, such as how to segment a given design into N uniformly magnetized pieces.Our method calculates the globally optimal shape and magnetization direction of each segment inside a certain......We present a semi-analytical algorithm for magnet design problems, which calculates the optimal way to subdivide a given design region into uniformly magnetized segments.The availability of powerful rare-earth magnetic materials such as Nd-Fe-B has broadened the range of applications of permanent...... designarea with an optional constraint on the total amount of magnetic material. The method can be applied to any objective functional which is linear respect to the field, and with any combination of linear materials. Being based on an analytical-optimization approach, the algorithm is not computationally...

  2. Magnetic Coordinate Systems

    CERN Document Server

    Laundal, K M

    2016-01-01

    Geospace phenomena such as the aurora, plasma motion, ionospheric currents and associated magnetic field disturbances are highly organized by Earth's main magnetic field. This is due to the fact that the charged particles that comprise space plasma can move almost freely along magnetic field lines, but not across them. For this reason it is sensible to present such phenomena relative to Earth's magnetic field. A large variety of magnetic coordinate systems exist, designed for different purposes and regions, ranging from the magnetopause to the ionosphere. In this paper we review the most common magnetic coordinate systems and describe how they are defined, where they are used, and how to convert between them. The definitions are presented based on the spherical harmonic expansion coefficients of the International Geomagnetic Reference Field (IGRF) and, in some of the coordinate systems, the position of the Sun which we show how to calculate from the time and date. The most detailed coordinate systems take the...

  3. The First Magnetic Fields

    CERN Document Server

    Widrow, Lawrence M; Schleicher, Dominik; Subramanian, Kandaswamy; Tsagas, Christos G; Treumann, Rudolf A

    2011-01-01

    We review current ideas on the origin of galactic and extragalactic magnetic fields. We begin by summarizing observations of magnetic fields at cosmological redshifts and on cosmological scales. These observations translate into constraints on the strength and scale magnetic fields must have during the early stages of galaxy formation in order to seed the galactic dynamo. We examine mechanisms for the generation of magnetic fields that operate prior during inflation and during subsequent phase transitions such as electroweak symmetry breaking and the quark-hadron phase transition. The implications of strong primordial magnetic fields for the reionization epoch as well as the first generation of stars is discussed in detail. The exotic, early-Universe mechanisms are contrasted with astrophysical processes that generate fields after recombination. For example, a Biermann-type battery can operate in a proto-galaxy during the early stages of structure formation. Moreover, magnetic fields in either an early genera...

  4. Remanent magnetism at Mars

    Science.gov (United States)

    Curtis, S. A.; Ness, N. F.

    1988-01-01

    It is shown that a strong case can be made for an intrinsic magnetic field of dynamo origin for Mars earlier in its history. The typical equatorial magnetic field intensity would have been equal to about 0.01-0.1 gauss. The earlier dynamo activity is no longer extant, but a significant remanent magnetic field may exist. A highly non-dipole magnetic field could result from the remanent magnetization of the surface. Remanent magnetization may thus play an important role in the Mars solar wind interactions, in contrast to Venus with its surface temperatures above the Curie point. The anomalous characteristics of Mars'solar wind interaction compared to that of Venus may be explicable on this basis.

  5. The 2017 Magnetism Roadmap

    Science.gov (United States)

    Sander, D.; Valenzuela, S. O.; Makarov, D.; Marrows, C. H.; Fullerton, E. E.; Fischer, P.; McCord, J.; Vavassori, P.; Mangin, S.; Pirro, P.; Hillebrands, B.; Kent, A. D.; Jungwirth, T.; Gutfleisch, O.; Kim, C. G.; Berger, A.

    2017-09-01

    Building upon the success and relevance of the 2014 Magnetism Roadmap, this 2017 Magnetism Roadmap edition follows a similar general layout, even if its focus is naturally shifted, and a different group of experts and, thus, viewpoints are being collected and presented. More importantly, key developments have changed the research landscape in very relevant ways, so that a novel view onto some of the most crucial developments is warranted, and thus, this 2017 Magnetism Roadmap article is a timely endeavour. The change in landscape is hereby not exclusively scientific, but also reflects the magnetism related industrial application portfolio. Specifically, Hard Disk Drive technology, which still dominates digital storage and will continue to do so for many years, if not decades, has now limited its footprint in the scientific and research community, whereas significantly growing interest in magnetism and magnetic materials in relation to energy applications is noticeable, and other technological fields are emerging as well. Also, more and more work is occurring in which complex topologies of magnetically ordered states are being explored, hereby aiming at a technological utilization of the very theoretical concepts that were recognised by the 2016 Nobel Prize in Physics. Given this somewhat shifted scenario, it seemed appropriate to select topics for this Roadmap article that represent the three core pillars of magnetism, namely magnetic materials, magnetic phenomena and associated characterization techniques, as well as applications of magnetism. While many of the contributions in this Roadmap have clearly overlapping relevance in all three fields, their relative focus is mostly associated to one of the three pillars. In this way, the interconnecting roles of having suitable magnetic materials, understanding (and being able to characterize) the underlying physics of their behaviour and utilizing them for applications and devices is well illustrated, thus giving an

  6. Molecules in Magnetic Fields

    Science.gov (United States)

    Berdyugina, Svetlana

    2015-08-01

    Molecules probe cool matter in the Universe and various astrophysical objects. Their ability to sense magnetic fields provides new insights into magnetic properties of these objects. During the past fifteen years we have carried out a theoretical study of molecular magnetic effects such as the Zeeman, Paschen-Back and Hanle effects and their applications for inferring magnetic structures and spatial inhomogeneities on the Sun, cool stars, brown dwarfs, and exoplanets from molecular spectro-polarimetry (e.g., Berdyugina 2011). Here, we present an overview of this study and compare our theoretical predictions with recent laboratory measurements of magnetic properties of some molecules. We present also a new web-based tool to compute molecular magnetic effects and polarized spectra which is supported by the ERC Advanced Grant HotMol.

  7. Magnetic nanocap arrays with tilted magnetization

    Science.gov (United States)

    Albrecht, Manfred

    2009-03-01

    In modern magnetic recording materials the ``superparamagnetic effect'' has become increasingly important as new magnetic hard disk drive products are designed for higher storage densities. In this regard, patterned media [1], where two-dimensional arrays of nanostructures are used, is one of the concepts that might provide the required areal density in future magnetic recording devices. However, also nanostructure arrays will ultimately need high anisotropy material such as L10-FePt to provid enough thermal stability and thus much higher writing fields than currently obtainable from perpendicular magnetic recording heads. One proposed solution to this problem is the use of tilted magnetic recording media [2]. The basic idea is to tilt the easy axis of the magnetic medium from the perpendicular direction to 45 degree. In this case, the switching field will be reduced by a foctor of two in the Stoner-Wohlfarth limit. Recently, this approach was realized by oblique film deposition onto arrays of self-assembled spherical particles [3-5]. In this presentation, recent results on different film systems including Co/Pt multilayers, FePt and CoPtCr-SiO2 alloys which have been deposited onto SiO2 particle monolayers will be presented. It turned out that by tuning the growth conditions single domain nanocaps with enhanced magnetic coercivity and tilted anisostropy axis can be achieved even for particle sizes below 50 nm. [4pt] [1] B. D. Terris and T. Thomson, J. Phys. D: Appl. Phys. 38 (2005) R199 [0pt] [2] J.-P. Wang, Nat. Mater. 4, 191 (2005). [0pt] [3] M. Albrecht et al., Nat. Mater. 4, 203 (2005). [0pt] [4] T. Ulbrich et al., Phys. Rev. Lett. 96 (2006) 077202. [0pt] [5] D. Makarov et al., Appl. Phys. Lett. 93, 153112 (2008).

  8. Mielopatia associada ao vírus linfotrópico humanode células T do tipo 1 (HTLV-1 Human T-cell lymphotropic virus type 1(HTLV-1 - associated myelopathy

    Directory of Open Access Journals (Sweden)

    João Gabriel Ramos Ribas

    2002-08-01

    stiffness of the lower limbs are common presenting signs and symptoms of HAM. Lower extremities are affected to a much greater degree than upper extremities. Spasticity may be moderate to severe, and lower back pain is common. As the disease progresses, bladder and bowel dysfunction can occur. Sensory involvement is generally mild and can result in a variable degree of sensory loss and dysesthesia. Results of magnetic resonance imaging may be normal, or the scans show atrophy of the spinal cord and nonspecific lesions in the brain. Immunologic evidence suggests that an immune mechanism may play a role in the development of HAM. There is no effective treatment for the myelopathy. Corticosteroids, and INF-gamma may produce transient responses. Danazol, an anabolic steroid, does not improve gait and bladder function. The value of zidovudine (anti-retroviral agent in the treatment has not been defined yet.

  9. Magnetic latching solenoid

    Science.gov (United States)

    Marts, D.J.; Richardson, J.G.; Albano, R.K.; Morrison, J.L. Jr.

    1995-11-28

    This invention discloses a D.C. magnetic latching solenoid that retains a moving armature in a first or second position by means of a pair of magnets, thereby having a zero-power requirement after actuation. The first or second position is selected by reversing the polarity of the D.C. voltage which is enough to overcome the holding power of either magnet and transfer the armature to an opposite position. The coil is then de-energized. 2 figs.

  10. Magnetic latching solenoid

    Energy Technology Data Exchange (ETDEWEB)

    Marts, Donna J. (Idaho Falls, ID); Richardson, John G. (Idaho Falls, ID); Albano, Richard K. (Idaho Falls, ID); Morrison, Jr., John L. (Idaho Falls, ID)

    1995-01-01

    This invention discloses a D.C. magnetic latching solenoid that retains a moving armature in a first or second position by means of a pair of magnets, thereby having a zero-power requirement after actuation. The first or second position is selected by reversing the polarity of the D.C. voltage which is enough to overcome the holding power of either magnet and transfer the armature to an opposite position. The coil is then de-energized.

  11. GHz magnetic film inductors

    CERN Document Server

    Korenivski, V

    2000-01-01

    Use of magnetic films for miniaturization of planar inductors operating at ultra-high frequencies is reviewed. Materials and design aspects determining the efficiency of the devices are analyzed. Mechanisms involved in magnetic dissipation and their role in limiting the device operation frequency range and quality factor are discussed. Typical inductor geometries are considered. A magnetically sandwiched strip inductor is argued to hold a promise for GHz applications.

  12. Organic magnetic field sensor

    Energy Technology Data Exchange (ETDEWEB)

    McCamey, Dane; Boehme, Christoph

    2017-01-24

    An organic, spin-dependent magnetic field sensor (10) includes an active stack (12) having an organic material with a spin-dependence. The sensor (10) also includes a back electrical contact (14) electrically coupled to a back of the active stack (12) and a front electrical contact (16) electrically coupled to a front of the active stack (12). A magnetic field generator (18) is oriented so as to provide an oscillating magnetic field which penetrates the active stack (12).

  13. Theoretical magnetic flux emergence

    OpenAIRE

    MacTaggart, David

    2011-01-01

    Magnetic flux emergence is the subject of how magnetic fields from the solar interior can rise and expand into the atmosphere to produce active regions. It is the link that joins dynamics in the convection zone with dynamics in the atmosphere. In this thesis, we study many aspects of magnetic flux emergence through mathematical modelling and computer simulations. Our primary aim is to understand the key physical processes that lie behind emergence. The first chapter intro...

  14. Magnetic record support

    Science.gov (United States)

    Nakayama, M.; Morita, H.; Tokuoka, Y.; Izumi, T.; Fukuda, K.; Kubota, Y.

    1984-01-01

    The magnetic layer of a magnetic record support is coated with a thin film of a polymer with a siloxane bond. The magnetic layer consists of a thin film obtained by vacuum metallization, cathode sputtering or dispersion of a ferromagnetic metal powder in a binder. The polymer with a siloxane bond is produced by the polymerization of an organic silicon compound which inherently contains or is able to form this bond. Polymerization is preferably performed by plasma polymerization.

  15. Magnetic Electrochemical Finishing Machining

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    How to improve the finishing efficiency and surface roughness have been all along the objective of research in electrochemical polishing. However, the research activity, i.e. during electrochemical polishing, directly introduce the magnetic field to study how the magnetic field influences on the finishing efficiency, quality and the electrochemical process in the field of finishing machining technology, is insufficient. When introducing additional magnetic field in the traditional electrochemical pol...

  16. Magnetic Spring Device

    OpenAIRE

    Hassam, A. B.; Rodgers, J. C.

    2009-01-01

    A cylindrical system is proposed that will store magnetic energy in a localized azimuthal field that can then be quickly released on Alfvenic timescales, accompanied by the formation of a flowing Z-pinch plasma. The magnetized plasma is MHD in character and will have unilateral axial momentum with Alfvenic speeds. Conventional plasma gun injectors (Marshall type) have a limited parameter space of operation. The "magnetic spring" momentum injector differs from Marshall guns in that it has an a...

  17. SPS : the magnet system

    CERN Multimedia

    CERN Neyrac Films

    1974-01-01

    English version. Part of a series of films about the SPS. This one ois from May 1974 to December 1974. Roy Billinge, Vince Hatton explain about magnet system. Technical requirements, accuracy checks, installation, magnetic measurements, mechanical measurements. Discussion of a particular problem which can come from variation in the thickness of the vacuum chambers. Dipoles, quadrapoles and other speciality magnets. Necessity for close international cooperation to coordinate the work. Nice meeting sequence at end. (calculator on the table.)

  18. Magnets in prosthetic dentistry.

    Science.gov (United States)

    Riley, M A; Walmsley, A D; Harris, I R

    2001-08-01

    Magnetic retention is a popular method of attaching removable prostheses to either retained roots or osseointegrated implants. This review chronicles the development of magnets in dentistry and summarizes future research in their use. The literature was researched by using the Science Citation Index and Compendex Web from 1981 to 2000. Articles published before 1981 were hand researched from citations in other publications. Articles that discussed the use of magnets in relation to prosthetic dentistry were selected.

  19. LHCb experiment magnets

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    The leading members of the LHCb magnet project, from left to right: Pierre-Ange Giudici, who organized and supervised the industrial production of the coils; Marcello Losasso, who performed the 3D calculations to optimise the magnetic field; Olivier Jamet, responsible for the 3D design; Jean Renaud, in charge of the magnet assembly, and Wilfried Flegel, project leader. The LHCb detector will investigate matter-antimatter differences in B mesons at the LHC. The coils of the detector's huge dipole magnet are seen here in April 2004.

  20. Biomaterials and magnetism

    Indian Academy of Sciences (India)

    D Bahadur; Jyotsnendu Giri

    2003-06-01

    Magnetism plays an important role in different applications of health care. Magnetite (Fe34) is biocompatible and therefore is one of the most extensively used biomaterials for different applications ranging from cell separation and drug delivery to hyperthermia. Other than this, a large number of magnetic materials in bulk as well as in the form of nano particles have been exploited for a variety of medical applications. In this review, we summarize the salient features of clinical applications, where magnetic biomaterials are used. Magnetic intracellular hyperthermia for cancer therapy is discussed in detail.

  1. Covariant Magnetic Connection Hypersurfaces

    CERN Document Server

    Pegoraro, F

    2016-01-01

    In the single fluid, nonrelativistic, ideal-Magnetohydrodynamic (MHD) plasma description magnetic field lines play a fundamental role by defining dynamically preserved "magnetic connections" between plasma elements. Here we show how the concept of magnetic connection needs to be generalized in the case of a relativistic MHD description where we require covariance under arbitrary Lorentz transformations. This is performed by defining 2-D {\\it magnetic connection hypersurfaces} in the 4-D Minkowski space. This generalization accounts for the loss of simultaneity between spatially separated events in different frames and is expected to provide a powerful insight into the 4-D geometry of electromagnetic fields when ${\\bf E} \\cdot {\\bf B} = 0$.

  2. Magnetic Nernst effect

    Science.gov (United States)

    Brechet, Sylvain D.; Ansermet, Jean-Philippe

    2015-09-01

    The thermodynamics of irreversible processes in continuous media predicts the existence of a magnetic Nernst effect that results from a magnetic analog to the Seebeck effect in a ferromagnet and magnetophoresis occurring in a paramagnetic electrode in contact with the ferromagnet. Thus, a voltage that has DC and AC components is expected across a Pt electrode as a response to the inhomogeneous magnetic induction field generated by magnetostatic waves of an adjacent YIG slab subject to a temperature gradient. The voltage frequency and dependence on the orientation of the applied magnetic induction field are quite distinct from that of spin pumping.

  3. Oscillating Permanent Magnets.

    Science.gov (United States)

    Michaelis, M. M.; Haines, C. M.

    1989-01-01

    Describes several ways to partially levitate permanent magnets. Computes field line geometries and oscillation frequencies. Provides several diagrams illustrating the mechanism of the oscillation. (YP)

  4. Magnetic flocculation and filtration

    Energy Technology Data Exchange (ETDEWEB)

    Yiacoumi, Sotira; Chin, Ching-Ju; Yin, Tung-Yu [Georgia Inst. of Tech., Atlanta, GA (United States). School of Civil and Environmental Engineering; Tsouris, C., DePaoli, D.W.; Chattin, M.R.; Spurrier, M. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    A model is available in predicting flocculation frequencies between particles of various properties under the influence of a magnetic field. This model provides a basic understanding of fundamental phenomena, such as particle-particle and particle-collector interactions, occurring in HGMF (high gradient magnetic field), and will be extended to describe experimental data of particle flocculation and filtration and predict the performance of high- gradient magnetic filters. It is also expected that this model will eventually lead to a tool for design and optimization of magnetic filters for environmental, metallurgical, biochemical, and other applications.

  5. Superconducting magnets for MRI

    Energy Technology Data Exchange (ETDEWEB)

    Williams, J.E.

    1984-08-01

    Three types of magnets are currently used to provide the background field required for magnet resonance imaging (MRI). (i) Permanent magnets produce fields of up to 0.3 T in volumes sufficient for imaging the head or up to 0.15 T for whole body imaging. Cost and simplicity of operation are advantages, but relatively low field, weight (up to 100 tonnes) and, to a small extent, instability are limitations. (ii) Water-cooled magnets provide fields of up to 0.25 T in volumes suitable for whole body imaging, but at the expense of power (up to 150 kW for 0.25 T) and water-cooling. Thermal stability of the field requires the maintenance of constant temperature through periods both of use and of quiescence. (iii) Because of the limitations imposed by permanent and resistive magnets, particularly on field strength, the superconducting magnet is now most widely used to provide background fields of up to 2 T for whole body MRI. It requires very low operating power and that only for refrigeration. Because of the constant low temperature, 4.2 K, at which its stressed structure operates, its field is stable. The following review deals principally with superconducting magnets for MRI. However, the sections on field analysis apply to all types of magnet and the description of the source terms of circular coils and of the principals of design of solenoids apply equally to resistive solenoidal magnets.

  6. Engineering magnetism in semiconductors

    Directory of Open Access Journals (Sweden)

    Tomasz Dietl

    2006-11-01

    Full Text Available Transition metal doped III-V, II-VI, and group IV compounds offer an unprecedented opportunity to explore ferromagnetism in semiconductors. Because ferromagnetic spin-spin interactions are mediated by holes in the valence band, changing the Fermi level using co-doping, electric fields, or light can directly manipulate the magnetic ordering. Moreover, engineering the Fermi level position by co-doping makes it possible to modify solubility and self-compensation limits, affecting magnetic characteristics in a number of surprising ways. The Fermi energy can even control the aggregation of magnetic ions, providing a new route to self-organization of magnetic nanostructures in a semiconductor host.

  7. Magnetic S-parameter

    DEFF Research Database (Denmark)

    Sannino, Francesco

    2010-01-01

    We propose a direct test of the existence of gauge duals for nonsupersymmetric asymptotically free gauge theories developing an infrared fixed point by computing the S-parameter in the electric and dual magnetic description. In particular we show that at the lower bound of the conformal window...... the magnetic S-parameter, i.e. the one determined via the dual magnetic gauge theory, assumes a simple expression in terms of the elementary magnetic degrees of freedom. The results further support our recent conjecture of the existence of a universal lower bound on the S parameter and indicates...

  8. Electromechanical magnetization switching

    Energy Technology Data Exchange (ETDEWEB)

    Chudnovsky, Eugene M. [Department of Physics and Astronomy, Lehman College and Graduate School, The City University of New York, 250 Bedford Park Boulevard West, Bronx, New York 10468-1589 (United States); Jaafar, Reem [Department of Mathematics, Engineering and Computer Science, LaGuardia Community College, The City University of New York, 31-10 Thomson Avenue, Long Island City, New York 11101 (United States)

    2015-03-14

    We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained.

  9. Magnetic chemically peculiar stars

    CERN Document Server

    Schöller, Markus

    2015-01-01

    Chemically peculiar (CP) stars are main-sequence A and B stars with abnormally strong or weak lines for certain elements. They generally have magnetic fields and all observables tend to vary with the same period. Chemically peculiar stars provide a wealth of information; they are natural atomic and magnetic laboratories. After a brief historical overview, we discuss the general properties of the magnetic fields in CP stars, describe the oblique rotator model, explain the dependence of the magnetic field strength on the rotation, and concentrate at the end on HgMn stars.

  10. Magnetism v.5

    CERN Document Server

    Suhl, Harry

    1973-01-01

    Magnetism, Volume V: Magnetic Properties of Metallic Alloys deals with the magnetic properties of metallic alloys and covers topics ranging from conditions favoring the localization of effective moments to the s-d model and the Kondo effect, along with perturbative, scattering, and Green's function theories of the s-d model. Asymptotically exact methods used in addressing the Kondo problem are also described.Comprised of 12 chapters, this volume begins with a review of experimental results and phenomenology concerning the formation of local magnetic moments in metals, followed by a Har

  11. Characteristics of shell-isolated nanoparticle-enhanced Raman spectroscopy of breast fibroadenoma and its clinical significance%乳腺纤维腺瘤表面增强拉曼光谱学特点及其临床意义

    Institute of Scientific and Technical Information of China (English)

    张海鹏; 付彤; 张喆; 吴迪; 范志民; 郑超; 韩冰

    2014-01-01

    目的:采用壳层隔绝纳米粒子增强拉曼光谱(SHINRES)检测乳腺纤维腺瘤和正常乳腺组织,通过探讨乳腺纤维腺瘤光谱学特点,探讨乳腺纤维腺瘤的生物学特征和鉴别方法。方法:收集乳腺外科手术患者的乳腺组织冰冻切片,共26例,均为女性,年龄19~59岁,乳腺纤维腺瘤17例,正常乳腺组织9例。冰冻切片解冻后先行普通拉曼光谱检测,加壳层隔绝纳米粒子(SHINs)后再次检测。共收集了243个拉曼光谱和273个SHINRES光谱,所有的光谱均进行基线修正拟合,再将所有的光谱用 Adjacent-Averaging算法进行15点平滑。结果:普通拉曼光谱检测,正常乳腺组织特征峰出现在1090、1157、1262、1300、1442、1658、1745和1874 cm-1;在加入SHINs后,少数特征峰的峰位出现2~3 cm-1位移,其中1090和1157 cm-1相对强度明显增加,出现1496 cm-1特征峰。纤维腺瘤主要的特征峰出现在751、880、930、1157、1262、1442、1579、1658和1745 cm-1,其中主导的特征峰应归属为脂类,但可见蛋白酰胺Ⅰ带特征峰。结论:拉曼光谱能够发现乳腺正常组织和纤维腺瘤组织中明显的蛋白酰胺Ⅰ带特征峰的差异。利用 SHINs对不同类型的乳腺组织最大增强的特征峰不同以及特征峰的最大增强倍数不同,可以区分乳腺纤维腺瘤和正常乳腺组织。%Objective To identify the normal breast tissue and breast fibroadenoma tissue by shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS),and to explore the biological characteristics of FD and the identification method by discussing its spectroscope characteristics.Methods The frozen section of 26 patients (all female,aged 19-59 years)were obtained by routine surgical resection.9 cases of normal tissue and 17 cases of breast fibroadenoma tissue were detected by Raman spectroscopy and then SHINERS technique was utilized.A total of 243 Raman and 273

  12. Radial Halbach Magnetic Bearings

    Science.gov (United States)

    Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

    2009-01-01

    Radial Halbach magnetic bearings have been investigated as part of an effort to develop increasingly reliable noncontact bearings for future high-speed rotary machines that may be used in such applications as aircraft, industrial, and land-vehicle power systems and in some medical and scientific instrumentation systems. Radial Halbach magnetic bearings are based on the same principle as that of axial Halbach magnetic bearings, differing in geometry as the names of these two types of bearings suggest. Both radial and axial Halbach magnetic bearings are passive in the sense that unlike most other magnetic bearings that have been developed in recent years, they effect stable magnetic levitation without need for complex active control. Axial Halbach magnetic bearings were described in Axial Halbach Magnetic Bearings (LEW-18066-1), NASA Tech Briefs, Vol. 32, No. 7 (July 2008), page 85. In the remainder of this article, the description of the principle of operation from the cited prior article is recapitulated and updated to incorporate the present radial geometry. In simplest terms, the basic principle of levitation in an axial or radial Halbach magnetic bearing is that of the repulsive electromagnetic force between (1) a moving permanent magnet and (2) an electric current induced in a stationary electrical conductor by the motion of the magnetic field. An axial or radial Halbach bearing includes multiple permanent magnets arranged in a Halbach array ("Halbach array" is defined below) in a rotor and multiple conductors in the form of wire coils in a stator, all arranged so the rotary motion produces an axial or radial repulsion that is sufficient to levitate the rotor. A basic Halbach array (see Figure 1) consists of a row of permanent magnets, each oriented so that its magnetic field is at a right angle to that of the adjacent magnet, and the right-angle turns are sequenced so as to maximize the magnitude of the magnetic flux density on one side of the row while

  13. Ultrafast magnetization dynamics in diluted magnetic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Morandi, O [INRIA Nancy Grand-Est and Institut de Recherche en Mathematiques Avancees, 7 rue Rene Descartes, F-67084 Strasbourg (France); Hervieux, P-A; Manfredi, G [Institut de Physique et Chimie des Materiaux de Strasbourg, 23 rue du Loess, F-67037 Strasbourg (France)], E-mail: morandi@dipmat.univpm.it

    2009-07-15

    We present a dynamical model that successfully explains the observed time evolution of the magnetization in diluted magnetic semiconductor quantum wells after weak laser excitation. Based on the pseudo-fermion formalism and a second-order many-particle expansion of the exact p-d exchange interaction, our approach goes beyond the usual mean-field approximation. It includes both the sub-picosecond demagnetization dynamics and the slower relaxation processes that restore the initial ferromagnetic order in a nanosecond timescale. In agreement with experimental results, our numerical simulations show that, depending on the value of the initial lattice temperature, a subsequent enhancement of the total magnetization may be observed within the timescale of a few hundred picoseconds.

  14. Electro-Magnetic Quadrupole Magnets in the LCLS FEL Undulator

    Energy Technology Data Exchange (ETDEWEB)

    Emma, P.

    2005-01-31

    We discuss various aspects of electro-magnetic quadrupole (EMQ) magnets for the LCLS FEL undulator, including their utility in beam-based alignment (BBA), magnet design issues, and impact on tunnel environment, reliability, and cost.

  15. Magnetic Properties and Intergranular Action in Bonded Hybrid Magnets

    Institute of Scientific and Technical Information of China (English)

    Hua Zhenghe; Li Shandong; Han Zhida; Wang Dunhui; Zhong Wei; Gu Benxi; Lu Mu; Zhang Jianrong; Du Youwei

    2007-01-01

    Magnetic properties and intergranular action in bonded hybrid magnets, based on NdFeB and strontium ferrite powders were investigated. The long-range magnetostatic interaction and short-range exchange coupling interaction existed simultaneously in bonded hybrid magnets, and neither of them could be neglected. Some magnetic property parameters of hybrid magnets could be approximately obtained by adding the hysteresis loops of two magnets pro rata.

  16. Magnetic absorption dichroism and sum rules in itinerant magnets

    OpenAIRE

    Strange, Paul

    1994-01-01

    In this letter we discuss X-ray magnetic dichroism in magnetic materials where an itinerant model of the magnetic behaviour is appropriate. Inspired by progress made in interpreting dichroism spectra in a localized approach, we show that dichroism spectra are an excellent measure of the orbital and spin magnetic moments in itinerant magnets. By performing an energy decomposition of the sum rules we show that the structure found in dichroism spectra reflects the energy dependence of the magnet...

  17. PS auxiliary magnet

    CERN Multimedia

    CERN PhotoLab

    1974-01-01

    Units of the PS auxiliary magnet system. The picture shows how the new dipoles, used for vertical and horizontal high-energy beam manipulation, are split for installation and removal so that it is not necessary to break the accelerator vacuum. On the right, adjacent to the sector valve and the windings of the main magnet, is an octupole of the set.

  18. Magnetic support system

    NARCIS (Netherlands)

    Nijsse, G.J.P.; Spronck, J.W.

    1999-01-01

    There is described a support system enabling supporting an object such as a platform (1) free from vibration, in that bearing elements (50) have a stiffness (k) which at a working point (z0) equals zero. A bearing element (50) comprises two magnetic couplings (51, 52) provided by permanent magnets

  19. Magnetic Particle Technology

    Science.gov (United States)

    Oliveira, Luiz C.A.; A. Rios, Rachel V.R.; Fabris, Jose D.; Lago, Rachel M.; Sapag, Karim

    2004-01-01

    An exciting laboratory environment is activated by the preparation and novel use of magnetic materials to decontaminate water through adsorption and magnetic removal of metals and organics. This uncomplicated technique is also adaptable to the possible application of adsorbents to numerous other environmental substances.

  20. Solid state magnetism

    CERN Document Server

    Crangle, John

    1991-01-01

    Solid state magnetism is important and attempts to understand magnetic properties have led to an increasingly deep insight into the fundamental make up of solids. Both experimental and theoretical research into magnetism continue to be very active, yet there is still much ground to cover before there can be a full understanding. There is a strong interplay between the developments of materials science and of magnetism. Hundreds of new materials have been dis­ covered, often with previously unobserved and puzzling magnetic prop­ erties. A large and growing technology exists that is based on the magnetic properties of materials. Very many devices used in everyday life involve magnetism and new applications are being invented all the time. Under­ standing the fundamental background to the applications is vital to using and developing them. The aim of this book is to provide a simple, up-to-date introduction to the study of solid state magnetism, both intrinsic and technical. It is designed to meet the needs a...

  1. Magnetically controlled permeability membranes

    KAUST Repository

    Kosel, Jurgen

    2013-10-31

    A bioactive material delivery system can include a thermoresponsive polymer membrane and nanowires distributed within the thermoresponsive polymer membrane. Magnetic activation of a thermoresponsive polymer membrane can take place via altering the magnetization or dimensions of nanowires dispersed or ordered within the membrane matrix.

  2. Selected topics in magnetism

    CERN Document Server

    Gupta, L C

    1993-01-01

    Part of the ""Frontiers in Solid State Sciences"" series, this volume presents essays on such topics as spin fluctuations in Heisenberg magnets, quenching of spin fluctuations by high magnetic fields, and kondo effect and heavy fermions in rare earths amongst others.

  3. Wobbly Corner: Magnetism

    Science.gov (United States)

    Corbett, Lisa; Maklad, Rania; Dunne, Mick; Grace, Pierre

    2014-01-01

    During a final seminar with BA year 4 science specialist trainee teachers, the authors posed a question about the difficulties associated with understanding magnetism. The ensuing discussion focused on a number of concerns commonly identified by students, which may also be of interest to classroom teachers teaching magnetism. Issues raised…

  4. Magnetization of ancient ceramics

    NARCIS (Netherlands)

    Van Klinken, J

    2001-01-01

    The saturation magnetization sigma of soft baked pottery appears to be determined during the firing process by transitions between the iron oxides magnetite, maghemite, hematite and perhaps goethite. The finding of large variations in a motivated the design and construction of a 'magnetization-gravi

  5. Magnetic support system

    NARCIS (Netherlands)

    Nijsse, G.J.P.; Spronck, J.W.

    1999-01-01

    There is described a support system enabling supporting an object such as a platform (1) free from vibration, in that bearing elements (50) have a stiffness (k) which at a working point (z0) equals zero. A bearing element (50) comprises two magnetic couplings (51, 52) provided by permanent magnets (

  6. Neutrino Magnetic Moment

    OpenAIRE

    Balantekin, A. B.

    2006-01-01

    Current experimental and observational limits on the neutrino magnetic moment are reviewed. Implications of the recent results from the solar and reactor neutrino experiments for the value of the neutrino magnetic moment are discussed. It is shown that spin-flavor precession in the Sun is suppressed.

  7. AGS Booster prototype magnets

    Energy Technology Data Exchange (ETDEWEB)

    Danby, G.; Jackson, J.; Lee, Y.Y.; Phillips, R.; Brodowski, J.; Jablonski, E.; Keohane, G.; McDowell, B.; Rodger, E.

    1987-03-19

    Prototype magnets have been designed and constructed for two half cells of the AGS Booster. The lattice requires 2.4m long dipoles, each curved by 10/sup 0/. The multi-use Booster injector requires several very different standard magnet cycles, capable of instantaneous interchange using computer control from dc up to 10 Hz.

  8. Magnetic Implants Aid Hearing

    Institute of Scientific and Technical Information of China (English)

    陈宏

    1995-01-01

    The next generation of hearing aids may use tiny magnets that fit inside the ear. Researchersat a California company and an engineer at the University of Virginia are both developing systems that rely on magnets to convey sounds. Conventional hearing aids have three components:a microphone, an amplifier, and a speaker. The microphone picks up sounds and sends them to the am-

  9. Magnetism in massive stars

    NARCIS (Netherlands)

    Henrichs, H.F.

    2012-01-01

    Stars with mass more than 8 solar masses end their lives as neutron stars, which we mostly observe as highly magnetized objects. Where does this magnetic field come from? Such a field could be formed during the collapse, or is a (modified) remnant of a fossil field since the birth of the star, or ot

  10. Checking BEBC superconducting magnet

    CERN Multimedia

    1974-01-01

    The superconducting coils of the magnet for the 3.7 m Big European Bubble Chamber (BEBC) had to be checked, see Annual Report 1974, p. 60. The photo shows a dismantled pancake. By December 1974 the magnet reached again the field design value of 3.5 T.

  11. Magnetic-seeding filtration

    Energy Technology Data Exchange (ETDEWEB)

    Ying, T.Y.; Chin, C.J.; Lu, S.C.; Yiacoumi, S. [Georgia Institute of Technology, Atlanta, GA (United States). School of Civil and Environmental Engineering] [and others

    1997-10-01

    Magnetic-seeding filtration consists of two steps: heterogeneous particle flocculation of magnetic and nonmagnetic particles in a stirred tank and high-gradient magnetic filtration (HGMF). The effects of various parameters affecting magnetic-seeding filtration (HGMF). The effects of various parameters affecting magnetic seeding filtration are theoretically and experimentally investigated. A trajectory model that includes hydrodynamic resistance, van der Waals, and electrostatic forces is developed to calculate the flocculation frequency in a turbulent-shear regime. Fractal dimension is introduced to simulate the open structure of aggregates. A magnetic-filtration model that consists of trajectory analysis, a particle build-up model, a breakthrough model, and a bivariate population-balance model is developed to predict the breakthrough curve of magnetic-seeding filtration. A good agreement between modeling results and experimental data is obtained. The results show that the model developed in this study can be used to predict the performance of magnetic-seeding filtration without using empirical coefficients or fitting parameters. 35 refs., 7 figs., 1 tab.

  12. Stellar magnetic cycles

    Science.gov (United States)

    Baliunas, S. L.

    2004-05-01

    Is hope for understanding the solar magnetic cycle to be found in stars? Observations of stars with significant sub-surface convective zones -- masses smaller than about 1.5 solar masses on the lower main sequence and many types of cool, post-main-sequence stars -- indicate the presence of surface and atmospheric inhomogeneities analogous to solar magnetic features, making stellar magnetic activity a cosmically widespread phenomenon. Observations have been made primarily in visible wavelengths, and important information has also been derived from the ultraviolet and x-ray spectrum regions. Interannual to interdecadal variability of spectrum indicators of stellar magnetic features is common, and in some cases similar in appearance to the 11-year sunspot cycle. Successful models of the physical processes responsible for stellar magnetic cycles, typically cast as a magnetohydrodynamic dynamo, require advances in understanding not only convection but also the magnetic field's interaction with it. The observed facts that underpin the hope for models will be summarized. Properties of stellar magnetic cycles will be compared and contrasted with those of the sun, including inferences from paleo-environmental reservoirs that contain information on solar century- to millennial-scale magnetic variability. Partial support of this research came from NASA NAG5-7635, NRC COBASE, CRDF 322, MIT-MSG 5710001241, JPL 1236821, AF 49620-02-1-0194, Richard Lounsberry Foundation, Langley-Abbot, Rollins, Scholarly Studies and James Arthur Funds (Smithsonian Institution) and several generous individuals.

  13. Streched Magnetic Moments

    CERN Document Server

    Zamick, Larry

    2012-01-01

    We note that for a system of 2 nucleons in a stretched case (J=J1+J2) the magnetic moment of the combined system is the sum of the magnetic moments of the 2 constituents. In general there is no additive rule for g factors.

  14. TMX magnets: mechanical design

    Energy Technology Data Exchange (ETDEWEB)

    Hinkle, R.E.; Harvey, A.R.; Calderon, M.O.; Chargin, A.K.; Chen, F.F.K.; Denhoy, B.S.; Horvath, J.A.; Reed, J.R.; Waugh, A.F.

    1977-09-27

    The Tandem Mirror Experiment (TMX) system, part of the Lawrence Livermore Laboratory magnetic mirror program incorporates in its design various types of coils or magnets. This paper describes the physical construction of each coil within the system as well as the structural design required for their support and installation.

  15. The LHCb magnet

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    The LHCb magnet consists of two huge 27 tonne coils mounted inside a 1450 tonne iron yoke. As charged particles pass through the magnet's field their trajectories will be bent according to their momentum, allowing their momentum to be measured as they pass through the detector walls. LHCb will study bottom quarks, which will be produced close to the two colliding proton beams.

  16. Magnetic Structure of Erbium

    DEFF Research Database (Denmark)

    Gibbs, D.; Bohr, Jakob; Axe, J. D.

    1986-01-01

    , and at positions split symmetrically about the fundamental. As the temperature is lowered below 52 K the charge and magnetic scattering display a sequence of lock-in transitions to rational wave vectors. A spin-slip description of the magnetic structure is presented which explains the wave vectors...

  17. Magnetic bipolar transistor

    OpenAIRE

    Fabian, Jaroslav; Zutic, Igor; Sarma, S. Das

    2003-01-01

    A magnetic bipolar transistor is a bipolar junction transistor with one or more magnetic regions, and/or with an externally injected nonequilibrium (source) spin. It is shown that electrical spin injection through the transistor is possible in the forward active regime. It is predicted that the current amplification of the transistor can be tuned by spin.

  18. Teaching Tips: Mind Magnets

    Science.gov (United States)

    Fortenberry, Callie L.; Fowler, Teri W.

    2006-01-01

    Mind magnets are maps to guide instruction and facilitate the comprehension processes. They extend individual comprehension strategy instruction, which does not typically show students how to link application of appropriate strategies to whole texts. The mind magnet framework allows teachers to plan powerful interactions between the reader and the…

  19. Strong Little Magnets

    Science.gov (United States)

    Moloney, Michael J.

    2007-01-01

    Did you know that some strong little cylindrical magnets available in local hardware stores can have an effective circumferential current of 2500 A? This intriguing information can be obtained by hanging a pair of magnets at the center of a coil, as shown in Fig. 1, and measuring the oscillation frequency as a function of coil current.

  20. Magnetic shape memory fatigue

    Science.gov (United States)

    Heczko, Oleg; Straka, Ladislav; Soderberg, Outi; Hannula, Simo-Pekka

    2005-05-01

    Single crystal specimens of having compositions close to Ni2MnGa and exhibiting magnetic shape memory effect (MSME) were tested in a rotating magnetic field at a frequency of 5.7 Hz. The applied magnetic field, about 0.7 T was strong enough to induce the MSME. Test of one specimen was discontinued because of the structural failure of the specimens after 0.5 million cycles. Second specimen was tested up to 37 millions cycles. The evolution of the martensitic morphology and crack propagation were observed by optical microscopy. To characterize the magnetic shape memory behavior the simultaneous measurements of the field-induced strain and magnetization as a function of the magnetic field and external load was used. The full MSM effect, about 6% obtained prior the test, decreased to about 3% during the first million cycles. This value stayed then approximately constant up to 37 millions cycles of rotating magnetic field. The magnetic field needed to initiate the MSME increased. The observed behavior is discussed within the framework of observed martensitic band structure in the specimens and the existence of initial cracks and other obstacles for martensitic twin boundary motion.

  1. One thousand magnets delivered!

    CERN Multimedia

    2005-01-01

    The little matchstick-like objects, neatly lined up like colouring pencils in their box, are in fact LHC magnets seen from the air. These particular ones are being stored at Point 19 just alongside SM18, the magnet assembly and testing hall, which can be seen on the right of the picture. On the right in the background, is the Meyrin site.

  2. Analogue Magnetism: An Ansatz

    CERN Document Server

    Osano, Bob

    2016-01-01

    We present an ansatz for the relationship between magnetic flux density and fluid vorticity evolution equations. We also suggest that the magnetic flux density evolution equations be compared to the evolution equation for an effective vorticity ($\\omega_{eff}$), which bears a power law relation to the ordinary vorticity.

  3. The magnetic properties of the hollow cylindrical ideal remanence magnet

    DEFF Research Database (Denmark)

    Bjørk, Rasmus

    2016-01-01

    We consider the magnetic properties of the hollow cylindrical ideal remanence magnet. This magnet is the cylindrical permanent magnet that generates a uniform field in the cylinder bore, using the least amount of magnetic energy to do so. The remanence distribution of this magnet is derived...... and the generated field is compared to that of a Halbach cylinder of equal dimensions. The ideal remanence magnet is shown in most cases to generate a significantly lower field than the equivalent Halbach cylinder, although the field is generated with higher efficiency. The most efficient Halbach cylinder is shown...... to generate a field exactly twice as large as the equivalent ideal remanence magnet....

  4. Magnetic Properties of Erbium Gallium Gallate under High Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    Zhang Xijuan; Cheng Haiying; Yang Cuihong; Wang Wei

    2004-01-01

    A theoretical investigation on the magnetic properties of rare-earth Er3+ in Er3 Ga5 O12 was reported. The average magnetic moments(M) for applied magnetic field H parallel to the [001 ], [ 100], [ 110], [ 111 ] direction was studied based on the quantum theory. Temperature dependence of the magnetic properties is analyzed for H applied parallel to the [ 100] and [ 111 ] crystallographic directions. The magnetization decreases with increasing temperature,showing good agreement with thermal effect. A strong anisotropy of the magnetization is found under high magnetic field, but when the magnetic field is small, M and H are proportional.

  5. The magnetic properties of the hollow cylindrical ideal remanence magnet

    CERN Document Server

    Bjørk, R

    2016-01-01

    We consider the magnetic properties of the hollow cylindrical ideal remanence magnet. This magnet is the cylindrical permanent magnet that generates a uniform field in the cylinder bore, using the least amount of magnetic energy to do so. The remanence distribution of this magnet is derived and the generated field is compared to that of a Halbach cylinder of equal dimensions. The ideal remanence magnet is shown in most cases to generate a significantly lower field than the equivalent Halbach cylinder, although the field is generated with higher efficiency. The most efficient Halbach cylinder is shown to generate a field exactly twice as large as the equivalent ideal remanence magnet.

  6. Magnetic forces produced by rectangular permanent magnets in static microsystems.

    Science.gov (United States)

    Gassner, Anne-Laure; Abonnenc, Mélanie; Chen, Hong-Xu; Morandini, Jacques; Josserand, Jacques; Rossier, Joel S; Busnel, Jean-Marc; Girault, Hubert H

    2009-08-21

    Finite element numerical simulations were carried out in 2D geometries to map the magnetic field and force distribution produced by rectangular permanent magnets as a function of their size and position with respect to a microchannel. A single magnet, two magnets placed in attraction and in repulsion have been considered. The goal of this work is to show where magnetic beads are preferentially captured in a microchannel. These simulations were qualitatively corroborated, in one geometrical case, by microscopic visualizations of magnetic bead plug formation in a capillary. The results show that the number of plugs is configuration dependent with: in attraction, one plug in the middle of the magnets; in repulsion, two plugs near the edges of the magnets; and with a single magnet, a plug close to the center of the magnet. The geometry of the magnets (h and l are the height and length of the magnets respectively) and their relative spacing s has a significant impact on the magnetic flux density. Its value inside a magnet increases with the h/l ratio. Consequently, bar magnets produce larger and more uniform values than flat magnets. The l/s ratio also influences the magnetic force value in the microchannel, both increasing concomitantly for all the configurations. In addition, a zero force zone in the middle appears in the attraction configuration as the l/s ratio increases, while with a single magnet, the number of maxima and minima goes from one to two, producing two focusing zones instead of only one.

  7. Magnetic separation of antibiotics by electrochemical magnetic seeding

    Energy Technology Data Exchange (ETDEWEB)

    Ihara, I; Toyoda, K [Department of Agricultural Engineering and Socio Economics, Kobe University, Nada, Kobe 657-8501 (Japan); Beneragama, N; Umetsu, K [Department of Animal Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555 (Japan)], E-mail: ihara@port.kobe-u.ac.jp

    2009-03-01

    Magnetic separation of several classes of antibiotics was investigated using electrochemical magnetic seeding. Electrocoagulation with a sacrificial anode followed by addition of magnetite particles was applied for the magnetic seeding of antibiotics. With electrochemical magnetic seeding using an iron anode, tetracycline antibiotics (oxytetracycline, chlortetracycline, doxycycline and tetracycline) and cephalosporin antibiotic (cefdinir) were rapidly removed from synthetic wastewater by magnetic separation using a neodymium magnet. Iron and aluminium anodes were suitable for magnetic seeding of the antibiotics. The results indicated that the ability of antibiotics to form strong complex with iron and aluminium allowed the higher removal by magnetic separation. This method would be appropriate for rapid treatment of antibiotics in wastewater.

  8. Review and comparison of magnet designs for magnetic refrigeration

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Bahl, Christian Robert Haffenden; Smith, Anders

    2010-01-01

    One of the key issues in magnetic refrigeration is generating the magnetic field that the magnetocaloric material must be subjected to. The magnet constitutes a major part of the expense of a complete magnetic refrigeration system and a large effort should therefore be invested in improving...... the magnet design. A detailed analysis of the efficiency of different published permanent magnet designs used in magnetic refrigeration applications is presented in this paper. Each design is analyzed based on the generated magnetic flux density, the volume of the region where this flux is generated...

  9. Quasi-continuous magnets

    Energy Technology Data Exchange (ETDEWEB)

    Sims, J.R. [Los Alamos National Lab., NM (United States); Naumovich, G.J.; Hoang, T.A.; Dent, P.C. [Everson Electric Co., Bethlehem, PA (United States)

    1996-05-01

    The National High Magnetic Field Laboratory is completing a quasi-continuous magnet which will sustain a constant field of 60 T for 100 ms in a 32-mm 77 K bore. This magnet consists of 9 mechanically independent, nested, liquid nitrogen-cooled coils which are individually reinforced by high-strength stainless steel outer shells. The coils were wound from rectangular large cross-section, high-strength, high-conductivity copper conductor insulated wtih polyimide and fiberglass tapes. After winding, the coils were inserted into closely fitted, stainless steel reinforcing shells and impregnated with epoxy resin. Design, analysis, material, fabrication and operational issues for this class of magnets are reviewed. Fabrication and quality assurance testing of the 60 T coil set are covered in detail. Future growth of and possible links from this technology to other magnet systems are discussed. Needed improvements in design, analysis, materials, and fabrication are outlined.

  10. Lanthanide single molecule magnets

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jinkui; Zhang, Peng [Chinese Academy of Sciences, Changchun (China). Changchun Inst. of Applied Chemistry

    2015-10-01

    This book begins by providing basic information on single-molecule magnets (SMMs), covering the magnetism of lanthanide, the characterization and relaxation dynamics of SMMs and advanced means of studying lanthanide SMMs. It then systematically introduces lanthanide SMMs ranging from mononuclear and dinuclear to polynuclear complexes, classifying them and highlighting those SMMs with high barrier and blocking temperatures - an approach that provides some very valuable indicators for the structural features needed to optimize the contribution of an Ising type spin to a molecular magnet. The final chapter presents some of the newest developments in the lanthanide SMM field, such as the design of multifunctional and stimuli-responsive magnetic materials as well as the anchoring and organization of the SMMs on surfaces. In addition, the crystal structure and magnetic data are clearly presented with a wealth of illustrations in each chapter, helping newcomers and experts alike to better grasp ongoing trends and explore new directions.

  11. GHz nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Cross, T.A.; Drobny, G.; Trewhella, J.

    1994-12-01

    For the past dozen years, 500- and 600-MHz spectrometers have become available in many laboratories. The first 600-MHz NMR spectrometer (at Carnegie Mellon University) was commissioned more than 15 years ago and, until 1994, represented the highest field available for high-resolution NMR. This year, we have witnessed unprecedented progress in the development of very high field magnets for NMR spectroscopy, including the delivery of the first commercial 750-MHz NMR spectrometers. In addition, NMR signals have been obtained from 20-Tesla magnets (850 MHz for {sup 1}H`s) at both Los Alamos National Laboratory and Florida State University in the NHMFL (National High Magnetic Field Laboratory). These preliminary experiments have been performed in magnets with 100-ppm homogeneity, but a 20-Tesla magnet developed for the NHMFL will be brought to field this year with a projected homogeneity of 0.1 ppm over a 1-cm-diam spherical volume.

  12. Electricity and magnetism

    CERN Document Server

    Purcell, Edward M

    2013-01-01

    For 50 years, Edward M. Purcell's classic textbook has introduced students to the wonders of electricity and magnetism. The third edition has been brought up to date and is now in SI units. It features hundreds of new examples, problems and figures and contains discussions of real-life applications. The textbook covers all the standard introductory topics, such as electrostatics, magnetism, circuits, electromagnetic waves and electric and magnetic fields in matter. Taking a non-traditional approach, magnetism is derived as a relativistic effect. Mathematical concepts are introduced in parallel with the physics topics at hand, making the motivations clear. Macroscopic phenomena are derived rigorously from microscopic phenomena. With worked examples, hundreds of illustrations and nearly 600 end-of-chapter problems and exercises, this textbook is ideal for electricity and magnetism courses. Solutions to the exercises are available for instructors at www.cambridge.org/9781107014022.

  13. Metallic Magnetic Nanoparticles

    Directory of Open Access Journals (Sweden)

    A. Hernando

    2005-01-01

    Full Text Available In this paper, we reviewed some relevant aspects of the magnetic properties of metallic nanoparticles with small size (below 4 nm, covering the size effects in nanoparticles of magnetic materials, as well as the appearance of magnetism at the nanoscale in materials that are nonferromagnetic in bulk. These results are distributed along the text that has been organized around three important items: fundamental magnetic properties, different fabrication procedures, and characterization techniques. A general introduction and some experimental results recently obtained in Pd and Au nanoparticles have also been included. Finally, the more promising applications of magnetic nanoparticles in biomedicine are indicated. Special care was taken to complete the literature available on the subject.

  14. Physics of magnetic nanostructures

    CERN Document Server

    Owens, Frank J

    2015-01-01

    This book discusses how the important properties of materials such as the cohesive energy, and the electronic and vibrational structures are affected when materials have at least one length in the nanometer range. The author uses relatively simple models of the solid state to explain why these changes in the size and dimension in the nanometer regime occur. The text also reviews the physics of magnetism and experimental methods of measuring magnetic properties necessary to understanding how nanosizing affects magnetism. Various kinds of magnetic structures are presented by the author in order to explain how nanosizing influences their magnetic properties. The book also presents potential and actual applications of nanomaterials in the fields of medicine and computer data storage.

  15. Superconducting Accelerator Magnets

    CERN Document Server

    Mess, K H; Wolff, S

    1996-01-01

    The main topic of the book are the superconducting dipole and quadrupole magnets needed in high-energy accelerators and storage rings for protons, antiprotons or heavy ions. The basic principles of low-temperature superconductivity are outlined with special emphasis on the effects which are relevant for accelerator magnets. Properties and fabrication methods of practical superconductors are described. Analytical methods for field calculation and multipole expansion are presented for coils without and with iron yoke. The effect of yoke saturation and geometric distortions on field quality is studied. Persistent magnetization currents in the superconductor and eddy currents the copper part of the cable are analyzed in detail and their influence on field quality and magnet performance is investigated. Superconductor stability, quench origins and propagation and magnet protection are addressed. Some important concepts of accelerator physics are introduced which are needed to appreciate the demanding requirements ...

  16. Magnetic entropy and cooling

    DEFF Research Database (Denmark)

    Hansen, Britt Rosendahl; Kuhn, Luise Theil; Bahl, Christian Robert Haffenden

    2010-01-01

    Some manifestations of magnetism are well-known and utilized on an everyday basis, e.g. using a refrigerator magnet for hanging that important note on the refrigerator door. Others are, so far, more exotic, such as cooling by making use of the magnetocaloric eect. This eect can cause a change...... or nitrogen liquefaction or for room-temperature cooling. The magnetocaloric eect can further be used to determine phase transition boundaries, if a change in the magnetic state occurs at the boundary.In this talk, I will introduce the magnetocaloric eect (MCE) and the two equations, which characterize...... in the temperature of a magnetic material when a magnetic eld is applied or removed. For many years, experimentalists have made use of dilute paramagnetic materials to achieve milliKelvin temperatures by use of the magnetocaloric eect. Also, research is done on materials, which might be used for hydrogen, helium...

  17. An integrated magnetics component

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention relates to an integrated magnetics component comprising a magnetically permeable core comprising a base member extending in a horizontal plane and first, second, third and fourth legs protruding substantially perpendicularly from the base member. First, second, third...... extending substantially orthogonally to the first flux path. Another aspect of the invention relates to a multiple-input isolated power converter comprising the integrated magnetics component....... and fourth output inductor windings are wound around the first, second, third and fourth legs, respectively. A first input conductor of the integrated magnetics component has a first conductor axis and extends in-between the first, second, third and fourth legs to induce a first magnetic flux through a first...

  18. Lanthanide single molecule magnets

    CERN Document Server

    Tang, Jinkui

    2015-01-01

    This book begins by providing basic information on single-molecule magnets (SMMs), covering the magnetism of lanthanide, the characterization and relaxation dynamics of SMMs, and advanced means of studying lanthanide SMMs. It then systematically introduces lanthanide SMMs ranging from mononuclear and dinuclear to polynuclear complexes, classifying them and highlighting those SMMs with high barrier and blocking temperatures – an approach that provides some very valuable indicators for the structural features needed to optimize the contribution of an Ising type spin to a molecular magnet. The final chapter presents some of the newest developments in the lanthanide SMM field, such as the design of multifunctional and stimuli-responsive magnetic materials as well as the anchoring and organization of the SMMs on surfaces. In addition, the crystal structure and magnetic data are clearly presented with a wealth of illustrations in each chapter, helping newcomers and experts alike to better grasp ongoing trends and...

  19. Study on healthcare magnetic concrete

    Institute of Scientific and Technical Information of China (English)

    YANG Yushan; DONG Faqin; FENG Jianjun

    2006-01-01

    Magnetic concrete was prepared by adding SrFe12O9 magnetic functional elementary material into concrete, and its magnetism was charged by magnetizing machine. The effect of SrFe12O9 content on magnetic field intensity and the attenuation of magnetic field intensity were investigated in different medium. The blood viscosity of rats kept in magnetic concrete was carried out. The results show that magnetic concrete can be prepared by adding SrFe12O9, and magnetic fields intensity increases with the augment of ferrite content. The attenuation of magnetic fields is mainly related with the density of medium, but it is secondary to the properties of medium. The blood viscosity of rats decreases under magnetic condition, but the blood cells remain the same as before. Experimental results support that magnetic concrete has great healthcare function.

  20. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... Us News Physician Resources Professions Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging ( ... if possible, or removed prior to the MRI scan. Because they can interfere with the magnetic field ...

  1. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) uses a powerful magnetic field, radio waves ...

  2. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... Resources Professions Site Index A-Z Children’s (Pediatric) Magnetic Resonance Imaging Children’s magnetic resonance imaging (MRI) uses a powerful magnetic field, radio ...

  3. Magnetic Resonance Imaging (MRI) -- Head

    Medline Plus

    Full Text Available ... Site Index A-Z Magnetic Resonance Imaging (MRI) - Head Magnetic resonance imaging (MRI) of the head uses ... of the Head? What is MRI of the Head? Magnetic resonance imaging (MRI) is a noninvasive medical ...

  4. Magnetically responsive dry fluids

    Science.gov (United States)

    Sousa, Filipa L.; Bustamante, Rodney; Millán, Angel; Palacio, Fernando; Trindade, Tito; Silva, Nuno J. O.

    2013-07-01

    Ferrofluids and dry magnetic particles are two separate classes of magnetic materials with specific niche applications, mainly due to their distinct viscosity and interparticle distances. For practical applications, the stability of these two properties is highly desirable but hard to achieve. Conceptually, a possible solution to this problem would be encapsulating the magnetic particles but keeping them free to rotate inside a capsule with constant interparticle distances and thus shielded from changes in the viscosity of the surrounding media. Here we present an example of such materials by the encapsulation of magnetic ferrofluids into highly hydrophobic silica, leading to the formation of dry ferrofluids, i.e., a material behaving macroscopically as a dry powder but locally as a ferrofluid where magnetic nanoparticles are free to rotate in the liquid.Ferrofluids and dry magnetic particles are two separate classes of magnetic materials with specific niche applications, mainly due to their distinct viscosity and interparticle distances. For practical applications, the stability of these two properties is highly desirable but hard to achieve. Conceptually, a possible solution to this problem would be encapsulating the magnetic particles but keeping them free to rotate inside a capsule with constant interparticle distances and thus shielded from changes in the viscosity of the surrounding media. Here we present an example of such materials by the encapsulation of magnetic ferrofluids into highly hydrophobic silica, leading to the formation of dry ferrofluids, i.e., a material behaving macroscopically as a dry powder but locally as a ferrofluid where magnetic nanoparticles are free to rotate in the liquid. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr01784b

  5. Rare Earths and Magnetic Refrigeration

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Magnetic refrigeration is a revolutionary, efficient, environmentally friendly cooling technology, which is on the threshold of commercialization. The magnetic rare earth materials are utilized as the magnetic refrigerants in most cooling devices, and for many cooling application the Nd2Fe14B permanent magnets are employed as the source of the magnetic field. The status of the near room temperature magnetic cooling was reviewed.

  6. Magnetic measurements inside the Omicron magnet.

    CERN Multimedia

    1977-01-01

    The multipurpose detection system (Omicron) built at the SC in the late seventies in the Proton Hall made use of the large aperture magnet (on loan from Rutherford Lab, 85 cm gap height, 1 m width, 1.8 m length, 1 Tesla peak field). See CERN Courier 17 (1977) p. 61.

  7. Magnetically Coupled Magnet-Spring Oscillators

    Science.gov (United States)

    Donoso, G.; Ladera, C. L.; Martin, P.

    2010-01-01

    A system of two magnets hung from two vertical springs and oscillating in the hollows of a pair of coils connected in series is a new, interesting and useful example of coupled oscillators. The electromagnetically coupled oscillations of these oscillators are experimentally and theoretically studied. Its coupling is electromagnetic instead of…

  8. Review and comparison of magnet designs for magnetic refrigeration

    CERN Document Server

    Bjørk, R; Smith, A; Pryds, N

    2014-01-01

    One of the key issues in magnetic refrigeration is generating the magnetic field that the magnetocaloric material must be subjected to. The magnet constitutes a major part of the expense of a complete magnetic refrigeration system and a large effort should therefore be invested in improving the magnet design. A detailed analysis of the efficiency of different published permanent magnet designs used in magnetic refrigeration applications is presented in this paper. Each design is analyzed based on the generated magnetic flux density, the volume of the region where this flux is generated and the amount of magnet material used. This is done by characterizing each design by a figure of merit magnet design efficiency parameter, $\\Lambda_\\mathrm{cool}$. The designs are then compared and the best design found. Finally recommendations for designing the ideal magnet design are presented based on the analysis of the reviewed designs.

  9. Magnetic Resonance Force Microscopy System

    Data.gov (United States)

    Federal Laboratory Consortium — The Magnetic Resonance Force Microscopy (MRFM) system, developed by ARL, is the world's most sensitive nuclear magnetic resonance (NMR) spectroscopic analysis tool,...

  10. Magnetism a very short introduction

    CERN Document Server

    Blundell, Stephen J

    2012-01-01

    Magnetism: A Very Short Introduction explains the mysteries and importance of magnetism. For centuries magnetism has been used for various exploits: as a great healer, a navigation aid through compasses, and through motors, generators, and turbines it has given us power. Our understanding of electricity and magnetism, from the work of Galvani, Ampère, Faraday, and Tesla is explored, and how Maxwell and Faraday's work led to the unification of electricity and magnetism is explained. With a discussion of the relationship between magnetism and relativity, quantum magnetism, and its impact on computers and information storage, how magnetism has changed our fundamental understanding of the Universe is shown.

  11. Electromagnetic acceleration of permanent magnets

    CERN Document Server

    Dolya, S N

    2015-01-01

    We consider the acceleration of the permanent magnets, consisting of neodymium iron boron by means of the running magnetic field gradient. It is shown that the specific magnetic moment per nucleon in neodymium iron boron is determined by the remained magnetization of the substance. The maximum accessable gradient of the magnetic field accelerating the permanent magnets is determined by the coercive force thirty kilogauss. For the neodymium iron boron magnets this gradient is equal to twenty kilogauss divided by one centimeter. The finite velocity of the magnets six kilometers per second, the length of acceleration is six hundred thirty-seven meters.

  12. Model of THz Magnetization Dynamics

    Science.gov (United States)

    Bocklage, Lars

    2016-01-01

    Magnetization dynamics can be coherently controlled by THz laser excitation, which can be applied in ultrafast magnetization control and switching. Here, transient magnetization dynamics are calculated for excitation with THz magnetic field pulses. We use the ansatz of Smit and Beljers, to formulate dynamic properties of the magnetization via partial derivatives of the samples free energy density, and extend it to solve the Landau-Lifshitz-equation to obtain the THz transients of the magnetization. The model is used to determine the magnetization response to ultrafast multi- and single-cycle THz pulses. Control of the magnetization trajectory by utilizing the THz pulse shape and polarization is demonstrated. PMID:26956997

  13. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... Magnetic Resonance, Functional (fMRI) - Brain Children's (Pediatric) CT (Computed Tomography) Magnetic Resonance Imaging (MRI) Safety Contrast Materials Children and Radiation ...

  14. Children's (Pediatric) Magnetic Resonance Imaging

    Medline Plus

    Full Text Available ... Magnetic Resonance, Functional (fMRI) - Brain Children's (Pediatric) CT (Computed Tomography) Magnetic Resonance Imaging (MRI) Safety Contrast Materials Children and Radiation Safety ...

  15. Active Magnetic Regenerative Liquefier

    Energy Technology Data Exchange (ETDEWEB)

    Barclay, John A. [Heracles Energy Corporation d.b.a. Prometheus Energy, Washington, DC (United States); Oseen-Send, Kathryn [Heracles Energy Corporation d.b.a. Prometheus Energy, Washington, DC (United States); Ferguson, Luke [Heracles Energy Corporation d.b.a. Prometheus Energy, Washington, DC (United States); Pouresfandiary, Jamshid [Heracles Energy Corporation d.b.a. Prometheus Energy, Washington, DC (United States); Cousins, Anand [Heracles Energy Corporation d.b.a. Prometheus Energy, Washington, DC (United States); Ralph, Heather [Heracles Energy Corporation d.b.a. Prometheus Energy, Washington, DC (United States); Hampto, Tom [Heracles Energy Corporation d.b.a. Prometheus Energy, Washington, DC (United States)

    2016-01-12

    This final report for the DOE Project entitled Active Magnetic Regenerative Liquefier (AMRL) funded under Grant DE-FG36-08GO18064 to Heracles Energy Corporation d.b.a. Prometheus Energy (Heracles/Prometheus) describes an active magnetic regenerative refrigerator (AMRR) prototype designed and built during the period from July 2008 through May 2011. The primary goal of this project was to make significant technical advances toward highly efficient liquefaction of hydrogen. Conventional hydrogen liquefiers at any scale have a maximum FOM of ~0.35 due primarily to the intrinsic difficulty of rapid, efficient compression of either hydrogen or helium working gases. Numerical simulation modeling of high performance AMRL designs indicates certain designs have promise to increase thermodynamic efficiency from a FOM of ~0.35 toward ~0.5 to ~0.6. The technical approach was the use of solid magnetic working refrigerants cycled in and out of high magnetic fields to build an efficient active regenerative magnetic refrigeration module providing cooling power for AMRL. A single-stage reciprocating AMRR with a design temperature span from ~290 K to ~120 K was built and tested with dual magnetic regenerators moving in and out of the conductively-cooled superconducting magnet subsystem. The heat transfer fluid (helium) was coupled to the process stream (refrigeration/liquefaction load) via high performance heat exchangers. In order to maximize AMRR efficiency a helium bypass loop with adjustable flow was incorporated in the design because the thermal mass of magnetic refrigerants is higher in low magnetic field than in high magnetic field. Heracles/Prometheus designed experiments to measure AMRR performance under a variety of different operational parameters such as cycle frequency, magnetic field strength, heat transfer fluid flow rate, amount of bypass flow of the heat transfer fluid while measuring work input, temperature span, cooling capability as a function of cold temperature

  16. MAGNETIC CIRCUIT EQUIVALENT OF THE SYNCHRONOUS MOTOR WITH INCORPORATED MAGNETS

    Directory of Open Access Journals (Sweden)

    Fyong Le Ngo

    2015-01-01

    Full Text Available Magnetic circuitry computation is one of the central stages of designing a synchronous motor with incorporated magnets, which can be performed by means of a simplified method of the magnetic-circuits equivalent modeling. The article studies the magnetic circuit of the motor with the rotor-incorporated magnets, which includes four sectors: constant magnets with the field pole extension made of magnetically soft steel, magniflux dispersion sections containing air barriers and steel bridges; the air gap; the stator grooves, cogs and the frame yoke. The authors introduce an equivalent model of the magnetic circuit. High-energy magnets with a linear demagnetization curve are employed in the capacity of constant magnets. Two magnets create the magnetic flux for one pole. The decline of magnetic potential in the steel of the pole is negligible consequent on the admission that the poles magnetic inductivity µ = ∞. The rotor design provides for the air barriers and the steel bridges that close leakage flux. The induction-permeability curve linearization serves for the bridges magnetic saturation accountability and presents a polygonal line consisting of two linear sections. The estimation of the magnet circuit section including the cogs and the frame yoke is executed with account of the steel saturation, their magnetic conductivities thereat being dependent on the saturation rate. Relying on the equivalent model of the magnetic circuit, the authors deduce a system of two equations written from the first and the second Kirchhoff laws of the magnetic circuits. These equations allow solving two problems: specifying dimensions of the magnets by the preset value of the magnetic flow in the clearance and determining the clearance magnetic flow at the preset motor rotor-and-stator design.

  17. Magnetic Coordinate Systems

    Science.gov (United States)

    Laundal, K. M.; Richmond, A. D.

    2017-03-01

    Geospace phenomena such as the aurora, plasma motion, ionospheric currents and associated magnetic field disturbances are highly organized by Earth's main magnetic field. This is due to the fact that the charged particles that comprise space plasma can move almost freely along magnetic field lines, but not across them. For this reason it is sensible to present such phenomena relative to Earth's magnetic field. A large variety of magnetic coordinate systems exist, designed for different purposes and regions, ranging from the magnetopause to the ionosphere. In this paper we review the most common magnetic coordinate systems and describe how they are defined, where they are used, and how to convert between them. The definitions are presented based on the spherical harmonic expansion coefficients of the International Geomagnetic Reference Field (IGRF) and, in some of the coordinate systems, the position of the Sun which we show how to calculate from the time and date. The most detailed coordinate systems take the full IGRF into account and define magnetic latitude and longitude such that they are constant along field lines. These coordinate systems, which are useful at ionospheric altitudes, are non-orthogonal. We show how to handle vectors and vector calculus in such coordinates, and discuss how systematic errors may appear if this is not done correctly.

  18. Magnetically mediated thermoacoustic imaging

    Science.gov (United States)

    Feng, Xiaohua; Gao, Fei; Zheng, Yuanjin

    2014-03-01

    In this paper, alternating magnetic field is explored for inducing thermoacoustic effect on dielectric objects. Termed as magnetically mediated thermo-acoustic (MMTA) effect that provides a contrast in conductivity, this approach employs magnetic resonance for delivering energy to a desired location by applying a large transient current at radio frequency below 50MHz to a compact magnetically resonant coil. The alternating magnetic field induces large electric field inside conductive objects, which then undergoes joule heating and emanates acoustic signal thermo-elastically. The magnetic mediation approach with low radio frequency can potentially provide deeper penetration than microwave radiation due to the non-magnetic nature of human body and therefore extend thermoacoustic imaging to deep laid organs. Both incoherent time domain method that applies a pulsed radio frequency current and coherent frequency domain approach that employs a linear chirp signal to modulate the envelop of the current are discussed. Owing to the coherent processing nature, the latter approach is capable of achieving much better signal to noise ratio and therefore potential for portable imaging system. Phantom experiments are carried out to demonstrate the signal generation together with some preliminary imaging results. Ex-vivo tissue studies are also investigated.

  19. Magnetically controlled solar nebula

    Science.gov (United States)

    Stepinski, T. F.; Reyes-Ruiz, M.

    1993-01-01

    It is widely believed that a primordial solar nebula, the precursor of the Sun and its planetary system, could be best described in terms of an accretion disk. Such an accretion disk is though to be turbulent, and it is usually imagined that turbulent viscosity alone provides the torque responsible for the structure and the evolution of the nebula. However, it was found that an MHD dynamo operating in a turbulent nebula can contemporaneously produce magnetic fields capable of significantly altering or even dominating the total torque. Thus, it seems that no model of a viscous solar nebula is complete without taking magnetic fields into consideration. It was demonstrated that there are usually two distinct regions of nebular disk where a dynamo can operate: the inner region, where the magnetic field coupled to gas due to relatively high thermal ionization; and the outer region, where this coupling is achieved due to nonthermal ionization. Most models also show the existence of an intermediate region, 'the magnetic gap,' where neither thermal nor nonthermal sources can produce enough ionization to provide the necessary coupling between the magnetic field and the gas. The location and width of the gap change substantially from one model to another. At present, we can only estimate the strength of a generated magnetic field. It seems that a large-scale magnetic field is likely to be in the equipartition with the turbulent kinetic energy; however, the intense magnetic fluctuations may greatly exceed this equipartition strength on short time and length scales. To show how a dynamo-generated magnetic field changes the structure of a viscous nebula, we consider four nebula models extensively.

  20. PREFACE: Geometrically frustrated magnetism Geometrically frustrated magnetism

    Science.gov (United States)

    Gardner, Jason S.

    2011-04-01

    Frustrated magnetism is an exciting and diverse field in condensed matter physics that has grown tremendously over the past 20 years. This special issue aims to capture some of that excitement in the field of geometrically frustrated magnets and is inspired by the 2010 Highly Frustrated Magnetism (HFM 2010) meeting in Baltimore, MD, USA. Geometric frustration is a broad phenomenon that results from an intrinsic incompatibility between some fundamental interactions and the underlying lattice geometry based on triangles and tetrahedra. Most studies have centred around the kagomé and pyrochlore based magnets but recent work has looked at other structures including the delafossite, langasites, hyper-kagomé, garnets and Laves phase materials to name a few. Personally, I hope this issue serves as a great reference to scientist both new and old to this field, and that we all continue to have fun in this very frustrated playground. Finally, I want to thank the HFM 2010 organizers and all the sponsors whose contributions were an essential part of the success of the meeting in Baltimore. Geometrically frustrated magnetism contents Spangolite: an s = 1/2 maple leaf lattice antiferromagnet? T Fennell, J O Piatek, R A Stephenson, G J Nilsen and H M Rønnow Two-dimensional magnetism and spin-size effect in the S = 1 triangular antiferromagnet NiGa2S4 Yusuke Nambu and Satoru Nakatsuji Short range ordering in the modified honeycomb lattice compound SrHo2O4 S Ghosh, H D Zhou, L Balicas, S Hill, J S Gardner, Y Qi and C R Wiebe Heavy fermion compounds on the geometrically frustrated Shastry-Sutherland lattice M S Kim and M C Aronson A neutron polarization analysis study of moment correlations in (Dy0.4Y0.6)T2 (T = Mn, Al) J R Stewart, J M Hillier, P Manuel and R Cywinski Elemental analysis and magnetism of hydronium jarosites—model kagome antiferromagnets and topological spin glasses A S Wills and W G Bisson The Herbertsmithite Hamiltonian: μSR measurements on single crystals

  1. Frontiers in Magnetic Materials

    CERN Document Server

    Narlikar, Anant V

    2005-01-01

    Frontiers in Magnetic Materials focuses on the current achievements and state-of-the-art advancements in magnetic materials. Several lines of development- High-Tc Superconductivity, Nanotechnology and refined experimental techniques among them – raised knowledge and interest in magnetic materials remarkably. The book comprises 24 chapters on the most relevant topics written by renowned international experts in the field. It is of central interest to researchers and specialists in Physics and Materials Science, both in academic and industrial research, as well as advanced students.

  2. Cryogenic Hybrid Magnetic Bearing

    Science.gov (United States)

    Meeks, Crawford R.; Dirusso, Eliseo; Brown, Gerald V.

    1994-01-01

    Cryogenic hybrid magnetic bearing is example of class of magnetic bearings in which permanent magnets and electromagnets used to suspend shafts. Electromagnets provide active control of position of shaft. Bearing operates at temperatures from -320 degrees F (-196 degrees C) to 650 degrees F (343 degrees C); designed for possible use in rocket-engine turbopumps, where effects of cryogenic environment and fluid severely limit lubrication of conventional ball bearings. This and similar bearings also suitable for terrestrial rotating machinery; for example, gas-turbine engines, high-vacuum pumps, canned pumps, precise gimbals that suspend sensors, and pumps that handle corrosive or gritty fluids.

  3. Magnetic-seeding filtration

    Energy Technology Data Exchange (ETDEWEB)

    Depaoli, D. [Oak Ridge National Lab., TN (United States)

    1996-10-01

    This task will investigate the capabilities of magnetic-seeding filtration for the enhanced removal of magnetic and nonmagnetic particulates from liquids. This technology appies to a wide range of liquid wastes, including groundwater, process waters, and tank supernatant. Magnetic-seeding filtration can be used in several aspects of treatment, such as (1) removal of solids, particularly those in the colloidal-size range that are difficult to remove by conventional means; (2) removal of contaminants by precipitation processes; and (3) removal of contaminants by sorption processes.

  4. Magnetic Actuators and Sensors

    Science.gov (United States)

    Brauer, John R.

    2005-12-01

    Magnetic actuators and sensors are needed to enable computer and manual control of motion. Magnetic actuators allow a small electrical signal to move small or large objects. To sense the amount of motion, magnetic sensors are frequently used. This book provides the most up-to-date coverage of topics important to modern engineers, both electrical and mechanical. The author includes the latest findings and design techniques from computer models. The latest software tools are used.

  5. Electrically controlled magnetism

    Science.gov (United States)

    Binek, Ch.; He, Xi; Wang, Yi; Sahoo, S.

    2008-08-01

    Manipulation of magnetically ordered states by electrical means is a promising approach towards novel spintronics devices. We report on the electric control of surface magnetism in Cr2O3 thin films and uniaxial anisotropy in ferroelectric/ferromagnetic heterostructures, respectively. Artificial magnetoelectricity is realized in a BaTiO3/Fe heterostructure. Here, thermally induced coercivity changes of the Fe hysteresis loop are used to derive the stress imposed by the ferroelectric BaTiO3 substrate on the adjacent Fe film. Electrically induced coercivity changes give rise to a giant magnetoelectric susceptibility in the vicinity of the magnetic coercive field.

  6. Magnetic refrigeration materials

    Institute of Scientific and Technical Information of China (English)

    戴闻; 沈保根; 高政祥

    2001-01-01

    Magnetic refrigeration has drawn much attention because of its greater efficiency and higher reliability than the traditional gas-cycle refrigeration technology. Recently, a kind of new materials with a giant magnetocaloric effect in the subroom temperature range, Gd5 (Six Ge1- x)4, was discovered, which boosts the search for high-performance magnetic refrigerants. However, the intermetallic compounds Gd5 (SixGe1 - x )4 belong to the first order transition materials; their performance in practical magnetic refrigeration cycles remains controversial. In this paper the developing tendency of the refrigerants are discussed on the basis of our work.

  7. Biomimetic magnetic nanoparticles

    Directory of Open Access Journals (Sweden)

    Michael T. Klem

    2005-09-01

    Full Text Available Magnetic nanoparticles are of considerable interest because of their potential use in high-density memory devices, spintronics, and applications in diagnostic medicine. The conditions for synthesis of these materials are often complicated by their high reaction temperatures, costly reagents, and post-processing requirements. Practical applications of magnetic nanoparticles will require the development of alternate synthetic strategies that can overcome these impediments. Biomimetic approaches to materials chemistry have provided a new avenue for the synthesis and assembly of magnetic nanomaterials that has great potential for overcoming these obstacles.

  8. Magnetic entropy and cooling

    DEFF Research Database (Denmark)

    Hansen, Britt Rosendahl; Kuhn, Luise Theil; Bahl, Christian Robert Haffenden

    2010-01-01

    in the temperature of a magnetic material when a magnetic eld is applied or removed. For many years, experimentalists have made use of dilute paramagnetic materials to achieve milliKelvin temperatures by use of the magnetocaloric eect. Also, research is done on materials, which might be used for hydrogen, helium...... the eect: the isothermal magnetic entropy change and the adiabatic temperature change. Some of the manifestations and utilizations of the MCE will be touched upon in a general way and nally I will talk about the results I have obtained on a sample of Gadolinium Iron Garnet (GdIG, Gd3Fe5O12), which...

  9. Advanced Magnetic Metrology Instrumentation

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The extraordinary progress in magnetic peripheral storage systems has been fueled by the ad vancements in heads (MR, GMR, spin valves) and in very high coercivity, Iow remanence thickness product (Mrt) media. These advancements are imposing new performance require ments on the magnetometers (VSMs) used to characterize these materials. At the same time, they have introduced a new paradigm for in-process (nondestructive, robotic) magnetic metrol ogy tools to assure the stringent product uniformity requirements. In this paper, we discuss the recent advancements in magnetometry for characterizing state-of-the-art media and heads, as well as other magnetic materials.

  10. Investigations on the magnetization behavior of magnetic composite particles

    Science.gov (United States)

    Eichholz, Christian; Knoll, Johannes; Lerche, Dietmar; Nirschl, Hermann

    2014-11-01

    In life sciences the application of surface functionalized magnetic composite particles is establishing in diagnostics and in downstream processing of modern biotechnology. These magnetic composite particles consist of non-magnetic material, e.g. polystyrene, which serves as a matrix for the second magnetic component, usually colloidal magnetite. Because of the multitude of magnetic cores these magnetic beads show a complex magnetization behavior which cannot be described with the available approaches for homogeneous magnetic material. Therefore, in this work a new model for the magnetization behavior of magnetic composite particles is developed. By introducing an effective magnetization and considering an overall demagnetization factor the deviation of the demagnetization of homogeneously magnetized particles is taken into account. Calculated and experimental results show a good agreement which allows for the verification of the adapted model of particle magnetization. Besides, a newly developed magnetic analyzing centrifuge is used for the characterization of magnetic composite particle systems. The experimental results, also used for the model verification, give both, information about the magnetic properties and the interaction behavior of particle systems. By adding further components to the particle solution, such as salts or proteins, industrial relevant systems can be reconstructed. The analyzing tool can be used to adapt industrial processes without time-consuming preliminary tests with large samples in the process equipments.

  11. Random porous media and magnetic separation of magnetic colloids

    NARCIS (Netherlands)

    Baars, R.J.

    2016-01-01

    The separation of magnetic nanoparticles from a stable dispersion is a challenging task because of the nanoparticles' thermal motion and relatively small magnetic moments. Strong magnetic gradients are required to capture such particles, which can be achieved in a high-gradient magnetic separator. I

  12. ANALYTIC EXPRESSION OF MAGNETIC FIELD DISTRIBUTION OF RECTANGULAR PERMANENT MAGNETS

    Institute of Scientific and Technical Information of China (English)

    苟晓凡; 杨勇; 郑晓静

    2004-01-01

    From the molecular current viewpoint,an analytic expression exactly describing magnetic field distribution of rectangular permanent magnets magnetized sufficiently in one direction was derived from the Biot-Savart's law. This expression is useful not only for the case of one rectangular permanent magnet bulk, but also for that of several rectangular permanent magnet bulks. By using this expression,the relations between magnetic field distribution and the size of rectangular permanent magnets as well as the magnitude of magnetic field and the distance from the point in the space to the top (or bottom) surface of rectangular permanent magnets were discussed in detail. All the calculating results are consistent with experimental ones. For transverse magnetic field which is a main magnetic field of rectangular permanent magnets,in order to describe its distribution,two quantities,one is the uniformity in magnitude and the other is the uniformity in distribution of magnetic field,were defined. Furthermore, the relations between them and the geometric size of the magnet as well as the distance from the surface of permanent magnets were investigated by these formulas. The numerical results show that the geometric size and the distance have a visible influence on the uniformity in magnitude and the uniformity in distribution of the magnetic field.

  13. Numerical analysis of thermally actuated magnets for magnetization of superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Li Quan; Yan Yu; Rawlings, Colin; Coombs, Tim, E-mail: ql229@cam.ac.u [EPEC Superconductivity Group, Engineering Department, University of Cambridge, Trumpington Street. Cambridge, CB2 1PZ (United Kingdom)

    2010-06-01

    Superconductors, such as YBCO bulks, have extremely high potential magnetic flux densities, comparing to rare earth magnets. Therefore, the magnetization of superconductors has attracted broad attention and contribution from both academic research and industry. In this paper, a novel technique is proposed to magnetize superconductors. Unusually, instead of using high magnetic fields and pulses, repeatedly magnetic waves with strength of as low as rare earth magnets are applied. These magnetic waves, generated by thermally controlling a Gadolinium (Gd) bulk with a rare earth magnet underneath, travel over the flat surface of a YBCO bulk and get trapped little by little. Thus, a very small magnetic field can be used to build up a very large magnetic field. In this paper, the modelling results of thermally actuated magnetic waves are presented showing how to transfer sequentially applied thermal pulses into magnetic waves. The experiment results of the magnetization of YBCO bulk are also presented to demonstrate how superconductors are progressively magnetized by small magnetic field

  14. Effective magnetic moment of neutrinos in strong magnetic fields

    CERN Document Server

    Pérez, A; Masood, S S; Gaitan, R; Rodríguez, S

    2002-01-01

    In this paper we compute the effective magnetic moment of neutrinos propagating in dense high magnetized medium. Taking typical values of magnetic field and densities of astrophysical objects (such as the cores of supernovae and neutron stars) we obtain an effective type of dipole magnetic moment in agreement with astrophysical and cosmological bounds. (Author)

  15. Modeling and analysis of magnetic dipoles in weak magnetic field

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The magnetic leakage field distribution resulting from linear defects of a tube sample in the geomagnetic field is modeled according to the magnetic dipole theory.The formula to compute the normal component of the weak magnetic field is deduced based on the spatial distribution of the magnetic dipole.The shape and characteristics of the zero line (an important criterion for magnetic memory testing) of the normal field is analyzed under different longitudinal magnetizations.Results show that the characteristics of the zero line should be considered when the metal magnetic memory testing method is used to find and locate the defect.

  16. Counseling blood donors seropositive for human T-lymphotropic virus types I and II in a developing country Aconselhando o doador de sangue soropositivo para o Vírus Linfotrópico Humano tipo I/II em um país em desenvolvimento

    Directory of Open Access Journals (Sweden)

    Valéria M. A. Passos

    1998-04-01

    Full Text Available Human T-lymphotropic virus types I and II (HTLV-I/II are blood-transmitted retroviruses associated with leukemia, myelopathy, and uveitis. From 51,135 eligible blood donors at the Fundação Hemominas tested in 1993, 689 (1.35% were repeatedly reactive to HTLV-I/II antibodies by enzyme immunoassay and were notified accordingly. Routes of transmission and preventive measures were emphasized in the orientation. Supplementary laboratory tests should be available and free of cost. Health services should recommend the use of latex condoms and make them available. Avoiding shared use of needles or syringes is important for both the seropositive donor and public health in general. In a country with such widespread malnutrition, the benefits of breast-feeding usually outweigh the risks of virus transmission. Based on our experience, we recommend that: 1 identical orientation be given to donors by all health professionals involved in counseling; 2 level of schooling be considered and information provided accordingly; 3 donors be assisted in understanding and assessing available information; 4 psychological assistance be provided to anxious or depressed donors; and 5 joint counseling be offered to donors with stable partners.Os vírus linfotrópico humano tipos I e II (HTLV-I/II são retrovírus transmitidos por componentes celulares sanguíneos e associados à ocorrência de leucemia, mielopatia e uveíte. De 51.135 doadores de sangue da Fundação Hemominas testados em 1993, 689 (1,35% foram repetidamente reativos a anticorpos contra HTLV-I/II no ensaio imunoenzimático e foram devidamente notificados. As vias de transmissão e medidas de controle foram enfatizadas na orientação. Testes laboratoriais suplementares devem ser disponíveis e gratuitos. O uso de preservativos deve ser recomendado e os mesmos serem disponíveis nos serviços de saúde. O doador soropositivo e os serviços de saúde não devem reutilizar agulhas e seringas. Sendo a desnutri

  17. Manifestações cutâneas da infecção e das doenças relacionadas ao vírus linfotrópico de células T humanas do tipo 1 Cutaneous manifestations in human T-cell lymphotropic virus type 1 infection

    Directory of Open Access Journals (Sweden)

    Marcelo Grossi Araújo

    2008-10-01

    Full Text Available O vírus linfotrópico de células T humanas tipo 1 (HTLV-1 é um retrovírus encontrado em todo o mundo e, no Brasil, tem distribuição heterogênea com várias regiões consideradas de alta prevalência. Está relacionado com doenças graves e/ou incapacitantes, como a leucemia/linfoma de células T do adulto, com a doença neurológica conhecida como mielopatia associada ao HTLV-1/paraparesia espástica tropical, com a uveíte associada ao HTLV-1 e com a dermatite infecciosa. O risco para o aparecimento dessas doenças depende, principalmente, de fatores genéticos, da forma como a infecção foi adquirida e da carga proviral. Estima-se que até 10% dos infectados possam desenvolver alguma doença relacionada ao vírus ao longo da vida. O comprometimento da pele tem sido descrito tanto nas doenças relacionadas ao HTLV-1 quanto nos indivíduos portadores assintomáticos. Vários mecanismos são propostos para explicar as lesões da pele, seja pela presença direta do vírus em células, pela imunossupressão ou por resposta inflamatória que a infecção pelo vírus poderia desencadear. Dentre as manifestações dermatológicas mais freqüentes destacam-se a xerose, as dermatofitoses e as infecções bacterianas recorrentes. Neste artigo são revistos os principais aspectos referentes à infecção e às doenças relacionadas ao HTLV- 1, com ênfase na discussão das manifestações dermatológicas observadas nesse contexto.Humam T lymphotropic virus type 1 (HTLV-1 has heteregenous distribution world-wide and, in Brazil, there are high prevalence areas. HTLV-1 has been associated to severe diseases, such as adult T cell leukaemia/ lymphoma, HTLV-1 associated myelopahthy/ tropical spastic parapesis, HTLV-1 associated uveitis and HTLV-1 associated infective dermatitis. Genetics, proviral load and infection route are related to disease risk along life. The lifetime risk to develop HTLV-1 related diseases may be close to 10%. Skin lesions are

  18. Human T-Cell Lymphotropic Virus Type I (HTLV-1: implications for autoimmune diseases Vírus linfotrópico de células T humano tipo 1 (HTLV-1: implicações em doenças autoimunes

    Directory of Open Access Journals (Sweden)

    Dênis Augusto Santana Reis

    2012-06-01

    Full Text Available Autoimmunity is characterized by tissue destruction that implicates functional damages caused by self-reactive cells that escape self-tolerance mechanisms. Autoimmune diseases can be initiated by viral infections and the study of the association between these viruses and autoimmunity has advanced the understanding of the molecular mechanisms involved in autoimmune diseases. The Human T-Cell Lymphotropic Virus Type I (HTLV-1 is a deltavirus that infects preferentially lymphocytes. Retrovirus particles like has been identified in patients with autoimmune diseases. Therefore this review had by objective approach the main aspects involving HTLV-1 with systemic lupus erythematosus and rheumatoid arthritis. Studies show that retroviruses can integrate their genetic material in host DNA, changing the expression gene profile related with apoptosis and immunologic system molecules. It’s known that HTLV-1 can cause different clinical manifestations in their careers and the mechanisms that triggers the HTLV-1 associated autoimmune diseases are not well known. Besides the perpetuation and marked production of pro-inflammatory cytokines, studies have demonstrated that both Th17 cells and T regulatory cells (Tregs are involved in autoimmune diseases pathogenesis. Therefore the HTLV-1 viral particles recognized could be used as a risk marker in the development of autoimmune diseases.A autoimunidade é caracterizada pela destruição tecidual, que acarreta danos funcionais, causados por células autoreativas que escapam dos mecanismos de autotolerância. Doenças autoimunes podem ser iniciadas por infecções virais e o estudo da associação entre essas viroses e a autoimunidade tem possibilitado melhor conhecimento dos mecanismos moleculares envolvidos nas doenças autoimunes. O vírus linfotrópico de células T humano tipo 1 (HTLV-1 é um delta vírus que infecta preferencialmente linfócitos. Partículas semelhantes aos retrovírus foram identificadas em

  19. Influence of human t-cell lymphotropic virus type 1 (HTLV-1 Infection on laboratory parameters of patients with chronic hepatitis C virus Influência da infecção pelo vírus linfotrópico humano tipo 1 (HTLV-1 em parâmetros laboratoriais de pacientes com hepatite C crônica

    Directory of Open Access Journals (Sweden)

    Daniela Fernandes Cardoso

    2009-12-01

    Full Text Available Hepatitis C virus (HCV and human T-cell lymphotropic virus type 1 (HTLV-1 share routes of transmission and some individuals have dual infection. Although some studies point to a worse prognosis of hepatitis C virus in patients co-infected with HTLV-1, the interaction between these two infections is poorly understood. This study evaluated the influence of HTLV-1 infection on laboratory parameters in chronic HCV patients. Twelve HTLV-1/HCV-coinfected patients were compared to 23 patients infected only with HCV, in regard to demographic data, risk factors for viral acquisition, HCV genotype, presence of cirrhosis, T CD4+ and CD8+ cell counts and liver function tests. There was no difference in regard to age, gender, alcohol consumption, smoking habits, HCV genotype or presence of cirrhosis between the groups. Intravenous drug use was the most common risk factor among individuals co-infected with HTLV-1. These patients showed higher TCD8+ counts (p = 0.0159 and significantly lower median values of AST and ALT (p = 0.0437 and 0.0159, respectively. In conclusion, we have shown that HCV/HTLV-1 co-infected patients differs in laboratorial parameters involving both liver and immunological patterns. The meaning of these interactions in the natural history of these infections is a matter that deserves further studies.O vírus da hepatite C (VHC e vírus linfotrópico humano tipo 1 (HTLV-1 compartilham formas de transmissão e algumas pessoas apresentam coinfecção. Embora alguns estudos apontem para um pior prognóstico da infecção pelo VHC em pacientes coinfectados com HTLV-1, a interação entre estas infecções é mal compreendida. Este estudo avaliou a influência da infecção pelo HTLV-1 em parâmetros laboratoriais de pacientes com VHC. 12 coinfectados VHC/HTLV-1 foram comparados com 23 pacientes monoinfectados com VHC, no que diz respeito aos dados demográficos, fatores de risco para aquisição viral, genótipo do VHC, presença de cirrose

  20. Magnetic Nanoparticles in Non-magnetic CNTs and Graphene

    Science.gov (United States)

    Kayondo, Moses; Seifu, Dereje

    Magnetic nanoparticles were embedded in non-magnetic CNTs and graphene matrix to incorporate all the advantages and the unique properties of CNTs and graphene. Composites of CNTs and graphene with magnetic nanoparticles may offer new opportunities for a wide variety of potential applications such as magnetic data storage, magnetic force microscopy tip, electromagnetic interference shields, thermally conductive films, reinforced polymer composites, transparent electrodes for displays, solar cells, gas sensors, magnetic nanofluids, and magnetically guided drug delivery systems. Magnetic nanoparticles coated CNTs can also be used as an electrode in lithium ion battery to replace graphite because of the higher theoretical capacity. Graphene nanocomposites, coated with magnetic sensitive nanoparticles, have demonstrated enhanced magnetic property. We would like to acknowledge support by NSF-MRI-DMR-1337339.

  1. Effects of magnetic field on fluidization properties of magnetic pearls

    Institute of Scientific and Technical Information of China (English)

    Maoming Fan; Zhenfu Luo; Yuemin Zhao; Qingru Chen; Daniel Tao; Xiuxiang Tao; Zhenqiang Chen

    2007-01-01

    An experimental study of the influence of external magnetic field on the fluidization behavior of magnetic pearls was carried out. Magnetic pearls are a magnetic form of iron oxide that mainly consists of Fe2O3 which are recovered from a high-volume power plant fly ash from pulverized coal combustion. Due to its abundance, low price and particular physical and chemical properties, magnetic pearls can be used as a heavy medium for minerals or solid waste dry separation based on density difference. This paper introduces the properties of magnetic pearls and compares the performance of magnetic pearls fluidised bed operation with or without an external magnetic field. Experimental results show that an external magnetic field significantly improves the fluidization performance of magnetic pearls such as uniformity and stability.

  2. Magnetic susceptibility, magnetization, magnetic moment and characterization of Carancas meteorite

    CERN Document Server

    Rosales, Domingo

    2015-01-01

    On September, 15th, 2007, in the community of Carancas (Puno, Peru) a stony meteorite formed a crater explosive type with a mean diameter of 13.5 m. some samples meteorite fragments were collected. The petrologic analysis performed corresponds to a meteorite ordinary chondrite H 4-5. In this paper we have analyzed the magnetic properties of a meteorite fragment with a proton magnetometer. Also in order to have a complete characterization of the Carancas meteorite and its crater, from several papers, articles and reports, we have made a compilation of the most important characteristics and properties of this meteorite.

  3. Magnetically Actuated Seal

    Science.gov (United States)

    Pinera, Alex

    2013-01-01

    This invention is a magnetically actuated seal in which either a single electromagnet, or multiple electromagnets, are used to control the seal's position. This system can either be an open/ close type of system or an actively controlled system.

  4. Magnetically Actuated Seal Project

    Data.gov (United States)

    National Aeronautics and Space Administration — FTT proposes development of a magnetically actuated dynamic seal. Dynamic seals are used throughout the turbopump in high-performance, pump-fed, liquid rocket...

  5. Self pumping magnetic cooling

    Science.gov (United States)

    Chaudhary, V.; Wang, Z.; Ray, A.; Sridhar, I.; Ramanujan, R. V.

    2017-01-01

    Efficient thermal management and heat recovery devices are of high technological significance for innovative energy conservation solutions. We describe a study of a self-pumping magnetic cooling device, which does not require external energy input, employing Mn-Zn ferrite nanoparticles suspended in water. The device performance depends strongly on magnetic field strength, nanoparticle content in the fluid and heat load temperature. Cooling (ΔT) by ~20 °C and ~28 °C was achieved by the application of 0.3 T magnetic field when the initial temperature of the heat load was 64 °C and 87 °C, respectively. These experiments results were in good agreement with simulations performed with COMSOL Multiphysics. Our system is a self-regulating device; as the heat load increases, the magnetization of the ferrofluid decreases; leading to an increase in the fluid velocity and consequently, faster heat transfer from the heat source to the heat sink.

  6. World Magnetic Model 2015

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The World Magnetic Model is the standard model used by the U.S. Department of Defense, the U.K. Ministry of Defence, the North Atlantic Treaty Organization (NATO)...

  7. Last PS magnet refurbished

    CERN Multimedia

    2009-01-01

    PS Magnet Refurbishment Programme Completed. The 51st and final refurbished magnet was transported to the PS on Tuesday 3 February. The repair and consolidation work on the PS started back in 2003 when two magnets and a busbar connection were found to be faulty during routine high-voltage tests. The cause of the fault was a combination of age and radiation on electrical insulation. After further investigation the decision was taken to overhaul half of the PS’s 100 magnets to reduce the risk of a similar fault. As from 20 February the PS ring will start a five-week test programme to be ready for operation at the end of March.

  8. Large Superconducting Magnet Systems

    CERN Document Server

    Védrine, P.

    2014-07-17

    The increase of energy in accelerators over the past decades has led to the design of superconducting magnets for both accelerators and the associated detectors. The use of Nb−Ti superconducting materials allows an increase in the dipole field by up to 10 T compared with the maximum field of 2 T in a conventional magnet. The field bending of the particles in the detectors and generated by the magnets can also be increased. New materials, such as Nb3Sn and high temperature superconductor (HTS) conductors, can open the way to higher fields, in the range 13–20 T. The latest generations of fusion machines producing hot plasma also use large superconducting magnet systems.

  9. Ultrafast Magnetic Light

    CERN Document Server

    Makarov, Sergey V; Krasnok, Alexander E; Belov, Pavel A

    2015-01-01

    We propose a novel concept for efficient dynamic tuning of optical properties of a high refractive index subwavelength nanoparticle with a magnetic Mie-type resonance by means of femtosecond laser radiation. This concept is based on ultrafast generation of electron-hole plasma within such nanoparticle, drastically changing its transient dielectric permittivity. This allows to manipulate by both electric and magnetic nanoparticle responses, resulting in dramatic changes of its extinction cross section and scattering diagram. Specifically, we demonstrate the effect of ultrafast switching-on a Huygens source in the vicinity of the magnetic dipole resonance. This approach enables to design ultrafast and compact optical switchers and modulators based on the "ultrafast magnetic light" concept.

  10. Magnetic interactions between nanoparticles

    DEFF Research Database (Denmark)

    Mørup, Steen; Hansen, Mikkel Fougt; Frandsen, Cathrine

    2010-01-01

    We present a short overview of the influence of inter-particle interactions on the properties of magnetic nanoparticles. Strong magnetic dipole interactions between ferromagnetic or ferrimagnetic particles, that would be superparamagnetic if isolated, can result in a collective state...... of nanoparticles. This collective state has many similarities to spin-glasses. In samples of aggregated magnetic nanoparticles, exchange interactions are often important and this can also lead to a strong suppression of superparamagnetic relaxation. The temperature dependence of the order parameter in samples...... of strongly interacting hematite nanoparticles or goethite grains is well described by a simple mean field model. Exchange interactions between nanoparticles with different orientations of the easy axes can also result in a rotation of the sub-lattice magnetization directions....

  11. Magnetic and superconducting nanowires

    DEFF Research Database (Denmark)

    Piraux, L.; Encinas, A.; Vila, L.

    2005-01-01

    magnetic and superconducting nanowires. Using different approaches entailing measurements on both single wires and arrays, numerous interesting physical properties have been identified in relation to the nanoscopic dimensions of these materials. Finally, various novel applications of the nanowires are also...

  12. 1000th magnet delivered!

    CERN Multimedia

    2006-01-01

    On Monday 20 February members of the AT Department marked the delivery of the 1000th superconducting dipole magnet to CERN. Only 232 more of the dipole magnets are needed for the LHC. The 35-tonne-dipoles are 15 meters long and are being manufactured by three companies: Babcock Noell Nuclear in Germany (which completed its contract in November 2005), Ansaldo Superconduttori in Italy and Alstom-Jeumont in France. 'The production is proceeding well and we expect to be complete in October as foreseen,' said Lucio Rossi, Head of the Magnets and Superconductors Group (AT-MAS). In total, 1650 main magnets are needed for the LHC, of which 1300 have already been delivered.

  13. 1000th magnet delivered!

    CERN Multimedia

    2006-01-01

    On Monday 20 February members of the AT Department marked the delivery of the 1000th superconducting dipole magnet to CERN. Only 232 more of the dipole magnets are needed for the LHC. The 35 tonne-dipoles are 15 meters long and are being manufactured by three companies: Babcock Noell Nuclear in Germany (which finished its contract in November 2005), Ansaldo Superconduttori in Italy and Alstom-Jeumont in France. "The production is proceeding well and we expect to be complete in October as previously foreseen," said Lucio Rossi, Head of the Magnets and Superconductors Group (AT-MAS). In total, 1650 main magnets are needed for the LHC, of which 1300 have been delivered.

  14. Magnetic Resonance Sensors

    Directory of Open Access Journals (Sweden)

    Robert H. Morris

    2014-11-01

    Full Text Available Magnetic Resonance finds countless applications, from spectroscopy to imaging, routinely in almost all research and medical institutions across the globe. It is also becoming more frequently used for specific applications in which the whole instrument and system is designed for a dedicated application. With beginnings in borehole logging for the petro-chemical industry Magnetic Resonance sensors have been applied to fields as varied as online process monitoring for food manufacture and medical point of care diagnostics. This great diversity is seeing exciting developments in magnetic resonance sensing technology published in application specific journals where they are often not seen by the wider sensor community. It is clear that there is enormous interest in magnetic resonance sensors which represents a significant growth area. The aim of this special edition of Sensors was to address the wide distribution of relevant articles by providing a forum to disseminate cutting edge research in this field in a single open source publication.[...

  15. Neutrino magnetic moment

    Energy Technology Data Exchange (ETDEWEB)

    Chang, D. (Northwestern Univ., Evanston, IL (USA). Dept. of Physics and Astronomy Fermi National Accelerator Lab., Batavia, IL (USA)); Senjanovic, G. (Zagreb Univ. (Yugoslavia). Dept. of Theoretical Physics)

    1990-01-01

    We review attempts to achieve a large neutrino magnetic moment ({mu}{sub {nu}} {le} 10{sup {minus}11}{mu}{sub B}), while keeping neutrino light or massless. The application to the solar neutrino puzzle is discussed. 24 refs.

  16. Magnetic Catalysis in Graphene

    CERN Document Server

    Winterowd, Christopher; Zafeiropoulos, Savvas

    2015-01-01

    One of the most important developments in condensed matter physics in recent years has been the discovery and characterization of graphene. A two-dimensional layer of Carbon arranged in a hexagonal lattice, graphene exhibits many interesting electronic properties, most notably that the low energy excitations behave as massless Dirac fermions. These excitations interact strongly via the Coulomb interaction and thus non-perturbative methods are necessary. Using methods borrowed from lattice QCD, we study the graphene effective theory in the presence of an external magnetic field. Graphene, along with other $(2+1)$-dimensional field theories, has been predicted to undergo spontaneous breaking of flavor symmetry including the formation of a gap as a result of the external magnetic field. This phenomenon is known as magnetic catalysis. Our study investigates magnetic catalysis using a fully non-perturbative approach.

  17. Quantum Theory of Magnetism

    CERN Document Server

    Nolting, Wolfgang

    2009-01-01

    Magnetism is one of the oldest and most fundamental problems of Solid State Physics although not being fully understood up to now. On the other hand it is one of the hottest topic of current research. Practically all branches of modern technological developments are based on ferromagnetism, especially what concerns information technology. The book, written in a tutorial style, starts from the fundamental features of atomic magnetism, discusses the essentially single-particle problems of dia- and paramagnetism, in order to provide the basis for the exclusively interesting collective magnetism (ferro, ferri, antiferro). Several types of exchange interactions, which take care under certain preconditions for a collective ordering of localized or itinerant permanent magnetic moments, are worked out. Under which conditions these exchange interactions are able to provoke a collective moment ordering for finite temperatures is investigated within a series of theoretical models, each of them considered for a very spec...

  18. ANOMALOUS MAGNETIC FILMS,

    Science.gov (United States)

    Three types of anomalous nickel-iron magnetic films characterized by hysteresigraph and torque-magnetometer measurements; bitter-pattern observations; reprint from ’ Journal of Applied Physics .’

  19. Magnetically Coupled Microcalorimeters

    Science.gov (United States)

    Bandler, S. R.; Irwin, K. D.; Kelly, D.; Nagler, P. N.; Porst, J. P.; Rotzinger, H.; Sadleir, J. E.; Seidel, G. M.; Smith, S. J.; Stevenson, T. R.

    2012-01-01

    Magnetic calorimeters have been under development for over 20 years targeting a wide variety of different applications that require very high resolution spectroscopy. They have a number of properties that distinguish them from other 10w temperature detectors. In this paper we review these properties and emphasize the types of application to which they are most suited. We will describe what has been learned about the best materials, geometries, and read-out amplifiers and our understanding of the measured performance and theoretical limits. While most magnetic calorimeter research has concentrated on the use of paramagnets to provide the temperature sensitivity, recently magnetically coupled microcalorimeters have been in development that utilize the diamagnetic response of superconductors. We will contrast some of the properties of the two different magnetic sensor types.

  20. Magnets for Pain Relief

    Science.gov (United States)

    ... better ways to prevent, diagnose, and treat diseases. Web site: www.nih.gov/health/clinicaltrials/ Key References Colbert AP, Markov MS, Souder JS. Static magnetic field therapy: dosimetry considerations. Journal of Alternative ...

  1. Magnetic vortex racetrack memory

    Science.gov (United States)

    Geng, Liwei D.; Jin, Yongmei M.

    2017-02-01

    We report a new type of racetrack memory based on current-controlled movement of magnetic vortices in magnetic nanowires with rectangular cross-section and weak perpendicular anisotropy. Data are stored through the core polarity of vortices and each vortex carries a data bit. Besides high density, non-volatility, fast data access, and low power as offered by domain wall racetrack memory, magnetic vortex racetrack memory has additional advantages of no need for constrictions to define data bits, changeable information density, adjustable current magnitude for data propagation, and versatile means of ultrafast vortex core switching. By using micromagnetic simulations, current-controlled motion of magnetic vortices in cobalt nanowire is demonstrated for racetrack memory applications.

  2. ISR Radial Field Magnet

    CERN Multimedia

    1983-01-01

    There were 37 (normal) + 3 (special) Radial Field magnets in the ISR to adjust vertically the closed orbit. Gap heights and strengths were 200 mm and .12 Tm in the normal magnets, 220 mm and .18 Tm in the special ones. The core length was 430 mm in both types. Due to their small length as compared to the gap heights the end fringe field errors were very important and had to be compensated by suitably shaping the poles. In order to save on cables, as these magnets were located very far from their power supplies, the coils of the normal type magnets were formed by many turns of solid cpper conductor with some interleaved layers of hollow conductor directly cooled by circulating water

  3. Magnetic gripper device

    Science.gov (United States)

    Meyer, Ross E.

    1993-01-01

    A climbing apparatus is provided for climbing ferromagnetic surfaces, such as storage tanks and steel frame structures. A magnet assembly is rotatably mounted in a frame assembly. The frame assembly provides a pair of cam surfaces having different dimensions so that, when the frame is rotated, the cam surfaces contact the ferromagnetic surface to separate the magnet assembly from the surface. The different cam dimensions enable one side of the magnet at a time to be detached from the surface to reduce the effort needed to disengage the climbing apparatus. The cam surface also provides for smoothly attaching the apparatus. A hardened dowel pin is also attached to the frame and the pointed end of the dowel engages the surface when the magnet is attached to the surface to prevent downward sliding movement of the assembly under the weight of the user.

  4. High field superconducting magnets

    Science.gov (United States)

    Hait, Thomas P. (Inventor); Shirron, Peter J. (Inventor)

    2011-01-01

    A superconducting magnet includes an insulating layer disposed about the surface of a mandrel; a superconducting wire wound in adjacent turns about the mandrel to form the superconducting magnet, wherein the superconducting wire is in thermal communication with the mandrel, and the superconducting magnet has a field-to-current ratio equal to or greater than 1.1 Tesla per Ampere; a thermally conductive potting material configured to fill interstices between the adjacent turns, wherein the thermally conductive potting material and the superconducting wire provide a path for dissipation of heat; and a voltage limiting device disposed across each end of the superconducting wire, wherein the voltage limiting device is configured to prevent a voltage excursion across the superconducting wire during quench of the superconducting magnet.

  5. Magnetic WKB Constructions

    Science.gov (United States)

    Bonnaillie-Noël, V.; Hérau, F.; Raymond, N.

    2016-08-01

    This paper is devoted to the semiclassical magnetic Laplacian. Until now WKB expansions for the eigenfunctions were only established in the presence of a non-zero electric potential. Here we tackle the pure magnetic case. Thanks to Feynman-Hellmann type formulas and coherent states decomposition, we develop here a magnetic Born-Oppenheimer theory. Exploiting the multiple scales of the problem, we are led to solve an effective eikonal equation in pure magnetic cases and to obtain WKB expansions.We also investigate explicit examples for which we can improve our general theorem: global WKB expansions, quasi-optimal Agmon estimates and upper bound of the tunelling effect (in symmetric cases).We also apply our strategy to get more accurate descriptions of the eigenvalues and eigenfunctions in a wide range of situations analyzed in the last two decades.

  6. World Magnetic Model 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The World Magnetic Model is the standard model used by the U.S. Department of Defense, the U.K. Ministry of Defence, the North Atlantic Treaty Organization (NATO)...

  7. Magnetic Pulse Welding Technology

    Directory of Open Access Journals (Sweden)

    Ahmad K. Jassim

    2011-12-01

    Full Text Available In this paper, the benefits of using Magnetic Pulse machine which is belong to Non-conventional machine instead of conventional machine. Magnetic Pulse Technology is used for joining dissimilar metals, and for forming and cutting metals. It is a non contact technique. Magnetic field is used to generate impact magnetic pressure for welding and forming the work piece by converted the electrical energy to mechanical energy. It is enable us to design previously not possible by welding dissimilar materials and allowing to welds light and stronger materials together. It can be used to weld metallic with non metallic materials to created mechanical lock on ceramics, polymers, rubbers and composites. It is green process; there is no heat, no radiation, no gas, no smoke and sparks, therefore the emissions are negligible.

  8. Magnetic separation of algae

    Energy Technology Data Exchange (ETDEWEB)

    Nath, Pulak; Twary, Scott N.

    2016-04-26

    Described herein are methods and systems for harvesting, collecting, separating and/or dewatering algae using iron based salts combined with a magnetic field gradient to separate algae from an aqueous solution.

  9. Study of Magnetic Nanocomposites by NMR and Bulk Magnetization Techniques

    Directory of Open Access Journals (Sweden)

    Matveev V.

    2014-07-01

    Full Text Available Magnetic nanocomposites possess complex and nonuniform magnetic structure. As a result it is necessary to use different physical methods to describe their properties. In this work we have applied a combination of micro and macro approaches to understand more deeply magnetic properties of some cobaltcontaining nanocomposites. Testing of magnetic structure of the samples at molecular level was done with NMR and Mössbauer techniques whereas static (SQUID and dynamic magnetic (M2, see below measurements – at macro level.

  10. Quantization of edge currents along magnetic barriers and magnetic guides

    CERN Document Server

    Dombrowski, N; Raikov, G D

    2010-01-01

    We investigate the edge conductance of particles submitted to an Iwatsuka magnetic field, playing the role of a purely magnetic barrier. We also consider magnetic guides generated by generalized Iwatsuka potentials. In both cases we prove quantization of the edge conductance. Next, we consider magnetic perturbations of such magnetic barriers or guides, and prove stability of the quantized value of the edge conductance. Further, we establish a sum rule for edge conductances. Regularization within the context of disordered systems is discussed as well.

  11. A superconducting magnetic gear

    Science.gov (United States)

    Campbell, A. M.

    2016-05-01

    A comparison is made between a magnetic gear using permanent magnets and superconductors. The objective is to see if there are any fundamental reasons why superconducting magnets should not provide higher power densities than permanent magnets. The gear is based on the variable permeability design of Attilah and Howe (2001 IEEE Trans. Magn. 37 2844-46) in which a ring of permanent magnets surrounding a ring of permeable pole pieces with a different spacing gives an internal field component at the beat frequency. Superconductors can provide much larger fields and forces but will saturate the pole pieces. However the gear mechanism still operates, but in a different way. The magnetisation of the pole pieces is now constant but rotates with angle at the beat frequency. The result is a cylindrical Halbach array which produces an internal field with the same symmetry as in the linear regime, but has an analytic solution. In this paper a typical gear system is analysed with finite elements using FlexPDE. It is shown that the gear can work well into the saturation regime and that the Halbach array gives a good approximation to the results. Replacing the permanent magnets with superconducting tapes can give large increases in torque density, and for something like a wind turbine a combined gear and generator is possible. However there are major practical problems. Perhaps the most fundamental is the large high frequency field which is inevitably present and which will cause AC losses. Also large magnetic fields are required, with all the practical problems of high field superconducting magnets in rotating machines. Nevertheless there are ways of mitigating these difficulties and it seems worthwhile to explore the possibilities of this technology further.

  12. Explosive Turbulent Magnetic Reconnection

    OpenAIRE

    Higashimori, Katsuaki; Yokoi, Nobumitsu; Hoshino, Masahiro

    2013-01-01

    We report simulation results for turbulent magnetic reconnection obtained using a newly developed Reynolds-averaged magnetohydrodynamics model. We find that the initial Harris current sheet develops in three ways, depending on the strength of turbulence: laminar reconnection, turbulent reconnection, and turbulent diffusion. The turbulent reconnection explosively converts the magnetic field energy into both kinetic and thermal energy of plasmas, and generates open fast reconnection jets. This ...

  13. Permanent magnet design methodology

    Science.gov (United States)

    Leupold, Herbert A.

    1991-01-01

    Design techniques developed for the exploitation of high energy magnetically rigid materials such as Sm-Co and Nd-Fe-B have resulted in a revolution in kind rather than in degree in the design of a variety of electron guidance structures for ballistic and aerospace applications. Salient examples are listed. Several prototype models were developed. These structures are discussed in some detail: permanent magnet solenoids, transverse field sources, periodic structures, and very high field structures.

  14. Biofunctionalized Magnetic Nanowires

    KAUST Repository

    Kosel, Jurgen

    2013-12-19

    Magnetic nanowires can be used as an alternative method overcoming the limitations of current cancer treatments that lack specificity and are highly cytotoxic. Nanowires are developed so that they selectively attach to cancer cells via antibodies, potentially destroying them when a magnetic field induces their vibration. This will transmit a mechanical force to the targeted cells, which is expected to induce apoptosis on the cancer cells.

  15. LHC Magnet test failure

    CERN Multimedia

    2007-01-01

    "On Tueday, March 22, a Fermilab-built quadrupole magnet, one of an "inner triplet" of three focusing magnets, failed a high-pressure test at Point 5 in the tunnel of the LHC accelerator at CERN. Since Tuesday, teams at CERN and Fermilab have worked closely together to address the problem and have identified the cause of the failure. Now they are at work on a solution.:" (1 page)

  16. Hybrid Magnetics and Power Applications

    DEFF Research Database (Denmark)

    Mo, Wai Keung; Paasch, Kasper

    A hybrid magnetic approach, merging two different magnetic core properites such as ferrite and iron powder cores, is an effective solution for power converter applications. It can offer similar magnetic properties to that of magnetic powder cores but showing less copper loss than powder cores...

  17. NMR magnet technology at MIT

    Energy Technology Data Exchange (ETDEWEB)

    Williams, J.E.C.; Bobrov, E.S.; Iwasa, Y.; Punchard, W.F.B.; Wrenn, J.; Zhukovsky, A. (Massachusetts Inst. of Tech., Cambridge, MA (United States). Francis Bitter National Magnet Lab.)

    1992-01-01

    The design and construction of high field superconducting NMR magnets has much in common with other types of adiabatic superconducting magnets. However, two issues have a particular relevance to NMR magnets. They are field drift and homogeneity. In this paper the control of these factors in the particular context of high field NMR spectrometer magnets is examined.

  18. Magnetic metallic multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Hood, R.Q.

    1994-04-01

    Utilizing self-consistent Hartree-Fock calculations, several aspects of multilayers and interfaces are explored: enhancement and reduction of the local magnetic moments, magnetic coupling at the interfaces, magnetic arrangements within each film and among non-neighboring films, global symmetry of the systems, frustration, orientation of the various moments with respect to an outside applied field, and magnetic-field induced transitions. Magnetoresistance of ferromagnetic-normal-metal multilayers is found by solving the Boltzmann equation. Results explain the giant negative magnetoresistance encountered in these systems when an initial antiparallel arrangement is changed into a parallel configuration by an external magnetic field. The calculation depends on (1) geometric parameters (thicknesses of layers), (2) intrinsic metal parameters (number of conduction electrons, magnetization, and effective masses in layers), (3) bulk sample properties (conductivity relaxation times), (4) interface scattering properties (diffuse scattering versus potential scattering at the interfaces, and (5) outer surface scattering properties (specular versus diffuse surface scattering). It is found that a large negative magnetoresistance requires considerable asymmetry in interface scattering for the two spin orientations. Features of the interfaces that may produce an asymmetrical spin-dependent scattering are studied: varying interfacial geometric random roughness with no lateral coherence, correlated (quasi-periodic) roughness, and varying chemical composition of the interfaces. The interplay between these aspects of the interfaces may enhance or suppress the magnetoresistance, depending on whether it increases or decreases the asymmetry in the spin-dependent scattering of the conduction electrons.

  19. Aging in Magnetic Superlattices

    Science.gov (United States)

    Mukherjee, Tathagata; Pleimling, Michel; Binek, Christian

    2010-03-01

    Aging phenomena can be observed in non-equilibrium systems with slow relaxation dynamics. Magnetic specimens with well defined interactions and dimensions can serve as model systems for universal aspects of aging. Magnetic thin films provide access to a wide range of microscopic parameters. Superlattice structures allow tuning the intra and inter-plane exchange and enable geometrical confinement of the spin fluctuations. We use Co/Cr thin film superlattices to study magnetic aging. The static and dynamic magnetic properties are affected via the Co and Cr film thicknesses. The Curie temperature of the Co films is reduced from the bulk value by geometrical confinement. Cr provides antiferromagnetic coupling between the Co films. In-plane magnetic set fields of some 10-100 mT are applied and the sample is exposed to the latter for various waiting times. After removing the field, relaxation of the magnetization is recorded via longitudinal Kerr-magnetometry and SQUID. The relaxation data are analyzed by scaling plots revealing universal aspects of aging. Financial support by NRI, and NSF through EPSCoR, Career DMR-0547887, DMR-0904999, and MRSEC.

  20. Soft magnetic wires

    Science.gov (United States)

    Vázquez, M.

    2001-06-01

    An overview of the present state of the art on the preparation techniques, outstanding magnetic properties and applications of soft magnetic micro and nanowires is presented. Rapid solidification techniques (in-rotating-water quenching and drawing methods) to fabricate amorphous microwires with diameter in the range from 100 down to 1 μm are first described. Electrodeposition is also employed to prepare composite microtubes (magnetic coatings) and to fill porous membranes (diameter of the order of 0.1 μm). Magnetic behaviours of interest are related to the different hysteresis loops of samples: square-shaped loops typical of bistable behaviour, and nearly non-hysteretic loop with well-defined transverse anisotropy field. The role played by magnetic dipolar interactions in the magnetic behaviour of arrays of micro and nanowires is described. A particular analysis is done on the giant magnetoimpedance (GMI) effect in the radio and microwave frequency ranges exhibited by ultrasoft microwires. Finally, a few examples of applications are introduced for magnetostrictive and non-magnetostrictive wires, they are: “magnetoelastic pens”, micromotors; DC current-sensors based on GMI, and sharpened amorphous wire tips in spin polarised scanning tunneling microscopy.

  1. Magnetic anisotropy in nanostructures

    CERN Document Server

    Eisenbach, M

    2001-01-01

    method for solving the LDA Kohn-Sham equation. This extended code allows us to perform fully relativistic calculations to enable us to investigate the spin orbit coupling effects leading to anisotropies and potentially non collinear ordering of magnetic moments in these systems of magnetic inclusions in copper. With this approach we find that depending on the orientation of the atoms along the 100 or 110 direction in copper the ground state orientation of the magnetic moments in the chain is either perpendicular or parallel to the chain direction, when the magnetic dipolar interaction energy is added to the final ab initio result. In this thesis we investigate the effect of magnetic anisotropies in nanostructured materials. The main emphasis in our work presented here is on systems that have an underlying one dimensional structure, like nanowires or atomic chains. In a simple classical one dimensional model we show the rich ground state structure of magnetic orientations one might expect to find in such syste...

  2. Magnetic flux concentration methods for magnetic energy harvesting module

    Directory of Open Access Journals (Sweden)

    Wakiwaka Hiroyuki

    2013-01-01

    Full Text Available This paper presents magnetic flux concentration methods for magnetic energy harvesting module. The purpose of this study is to harvest 1 mW energy with a Brooks coil 2 cm in diameter from environmental magnetic field at 60 Hz. Because the harvesting power is proportional to the square of the magnetic flux density, we consider the use of a magnetic flux concentration coil and a magnetic core. The magnetic flux concentration coil consists of an air­core Brooks coil and a resonant capacitor. When a uniform magnetic field crossed the coil, the magnetic flux distribution around the coil was changed. It is found that the magnetic field in an area is concentrated larger than 20 times compared with the uniform magnetic field. Compared with the air­core coil, our designed magnetic core makes the harvested energy ten­fold. According to ICNIRP2010 guideline, the acceptable level of magnetic field is 0.2 mT in the frequency range between 25 Hz and 400 Hz. Without the two magnetic flux concentration methods, the corresponding energy is limited to 1 µW. In contrast, our experimental results successfully demonstrate energy harvesting of 1 mW from a magnetic field of 0.03 mT at 60 Hz.

  3. Interaction between two magnetic dipoles in a uniform magnetic field

    Directory of Open Access Journals (Sweden)

    J. G. Ku

    2016-02-01

    Full Text Available A new formula for the interaction force between two magnetic dipoles in a uniform magnetic field is derived taking their mutual magnetic interaction into consideration and used to simulate their relative motion. Results show that when the angle β between the direction of external magnetic field and the centerline of two magnetic dipoles is 0 ° or 90 °, magnetic dipoles approach each other or move away from each other in a straight line, respectively. And the time required for them to contact each other from the initial position is related to the specific susceptibility and the diameter of magnetic particles, medium viscosity and magnetic field strength. When β is between 0 ° and 90 °, magnetic dipole pair performs approximate elliptical motion, and the motion trajectory is affected by the specific susceptibility, diameter and medium viscosity but not magnetic field strength. However, time required for magnetic dipoles to complete the same motion trajectory is shorter when adopting stronger magnetic field. Moreover, the subsequent motion trajectory of magnetic dipoles is ascertained once the initial position is set in a predetermined motion trajectory. Additionally, magnetic potential energy of magnetic dipole pairs is transformed into kinetic energy and friction energy during the motion.

  4. MAGNETIC NEUTRON SCATTERING

    Energy Technology Data Exchange (ETDEWEB)

    ZALIZNYAK,I.A.; LEE,S.H.

    2004-07-30

    Much of our understanding of the atomic-scale magnetic structure and the dynamical properties of solids and liquids was gained from neutron-scattering studies. Elastic and inelastic neutron spectroscopy provided physicists with an unprecedented, detailed access to spin structures, magnetic-excitation spectra, soft-modes and critical dynamics at magnetic-phase transitions, which is unrivaled by other experimental techniques. Because the neutron has no electric charge, it is an ideal weakly interacting and highly penetrating probe of matter's inner structure and dynamics. Unlike techniques using photon electric fields or charged particles (e.g., electrons, muons) that significantly modify the local electronic environment, neutron spectroscopy allows determination of a material's intrinsic, unperturbed physical properties. The method is not sensitive to extraneous charges, electric fields, and the imperfection of surface layers. Because the neutron is a highly penetrating and non-destructive probe, neutron spectroscopy can probe the microscopic properties of bulk materials (not just their surface layers) and study samples embedded in complex environments, such as cryostats, magnets, and pressure cells, which are essential for understanding the physical origins of magnetic phenomena. Neutron scattering is arguably the most powerful and versatile experimental tool for studying the microscopic properties of the magnetic materials. The magnitude of the cross-section of the neutron magnetic scattering is similar to the cross-section of nuclear scattering by short-range nuclear forces, and is large enough to provide measurable scattering by the ordered magnetic structures and electron spin fluctuations. In the half-a-century or so that has passed since neutron beams with sufficient intensity for scattering applications became available with the advent of the nuclear reactors, they have became indispensable tools for studying a variety of important areas of modern

  5. MAGNETIC NEUTRON SCATTERING

    Energy Technology Data Exchange (ETDEWEB)

    ZALIZNYAK,I.A.; LEE,S.H.

    2004-07-30

    Much of our understanding of the atomic-scale magnetic structure and the dynamical properties of solids and liquids was gained from neutron-scattering studies. Elastic and inelastic neutron spectroscopy provided physicists with an unprecedented, detailed access to spin structures, magnetic-excitation spectra, soft-modes and critical dynamics at magnetic-phase transitions, which is unrivaled by other experimental techniques. Because the neutron has no electric charge, it is an ideal weakly interacting and highly penetrating probe of matter's inner structure and dynamics. Unlike techniques using photon electric fields or charged particles (e.g., electrons, muons) that significantly modify the local electronic environment, neutron spectroscopy allows determination of a material's intrinsic, unperturbed physical properties. The method is not sensitive to extraneous charges, electric fields, and the imperfection of surface layers. Because the neutron is a highly penetrating and non-destructive probe, neutron spectroscopy can probe the microscopic properties of bulk materials (not just their surface layers) and study samples embedded in complex environments, such as cryostats, magnets, and pressure cells, which are essential for understanding the physical origins of magnetic phenomena. Neutron scattering is arguably the most powerful and versatile experimental tool for studying the microscopic properties of the magnetic materials. The magnitude of the cross-section of the neutron magnetic scattering is similar to the cross-section of nuclear scattering by short-range nuclear forces, and is large enough to provide measurable scattering by the ordered magnetic structures and electron spin fluctuations. In the half-a-century or so that has passed since neutron beams with sufficient intensity for scattering applications became available with the advent of the nuclear reactors, they have became indispensable tools for studying a variety of important areas of modern

  6. Planet migration and magnetic torques

    Science.gov (United States)

    Strugarek, A.; Brun, A. S.; Matt, S. P.; Reville, V.

    2016-10-01

    The possibility that magnetic torques may participate in close-in planet migration has recently been postulated. We develop three dimensional global models of magnetic star-planet interaction under the ideal magnetohydrodynamic (MHD) approximation to explore the impact of magnetic topology on the development of magnetic torques. We conduct twin numerical experiments in which only the magnetic topology of the interaction is altered. We find that magnetic torques can vary by roughly an order of magnitude when varying the magnetic topology from an aligned case to an anti-aligned case. Provided that the stellar magnetic field is strong enough, we find that magnetic migration time scales can be as fast as ~100 Myr. Hence, our model supports the idea that magnetic torques may participate in planet migration for some close-in star-planet systems.

  7. Magnetic separation in microfluidic systems

    DEFF Research Database (Denmark)

    Smistrup, Kristian

    2007-01-01

    This Ph.D. thesis presents theory, modeling, design, fabrication, experiments and results for microfluidic magnetic separators. A model for magnetic bead movement in a microfluidic channel is presented, and the limits of the model are discussed. The effective magnetic field gradient is defined...... for fabrication of silicon based systems. This fabrication scheme is explained, and it is shown how, it is applied with variations for several designs of magnetic separators. An experimental setup for magnetic separation experiments has been developed. It has been coupled with an image analysis program....... It is shown conceptually how such a system can be applied for parallel biochemical processing in a microfluidic system. ’Passive’ magnetic separators are presented, where on-chip soft magnetic elements are magnetized by an external magnetic field and create strong magnetic fields and gradients inside...

  8. Study of Magnetic Domain Dynamics Using Nonlinear Magnetic Responses: Magnetic Diagnostics of the Itinerant Magnet MnP

    Science.gov (United States)

    Mito, Masaki; Matsui, Hideaki; Tsuruta, Kazuki; Deguchi, Hiroyuki; Kishine, Jun-ichiro; Inoue, Katsuya; Kousaka, Yusuke; Yano, Shin-ichiro; Nakao, Yuya; Akimitsu, Jun

    2015-10-01

    The nonlinear and linear magnetic responses to an ac magnetic field H are useful for the study of the magnetic dynamics of both magnetic domains and their constituent spins. In particular, the third-harmonic magnetic response M3ω reflects the dynamics of magnetic domains. Furthermore, by considering the ac magnetic response as a function of H, we can evaluate the degree of magnetic nonlinearity, which is closely related to M3ω. In this study, a series of approaches was used to examine the itinerant magnet MnP, in which both ferromagnetic and helical phases are present. On the basis of this investigation, we systematize the diagnostic approach to evaluating nonlinearity in magnetic responses.

  9. Lodestone: Nature's own permanent magnet

    Science.gov (United States)

    Wasilewski, P.

    1976-01-01

    Magnetic hysteresis and microstructural details are presented which explain why the class of magnetic iron ores defined as proto-lodestones, can behave as permanent magnets, i.e. lodestones. Certain of these proto-lodestones which are not permanent magnets can be made into permanent magnets by charging in a field greater than 1000 oersted. This fact, other experimental observations, and field evidence from antiquity and the middle ages, which seems to indicate that lodestones are found as localized patches within massive ore bodies, suggests that lightning might be responsible for the charging of lodestones. The large remanent magnetization, high values of coercive force, and good time stability for the remanent magnetization are all characteristics of proto-lodestone iron ores which behave magnetically as fine scale ( 10 micrometer) intergrowths when subjected to magnetic hysteresis analysis. The magnetic results are easily understood by analysis of the complex proto lodestone microstructural patterns observable at the micrometer scale and less.

  10. Handbook of Advanced Magnetic Materials

    CERN Document Server

    Liu, Yi; Shindo, Daisuke

    2006-01-01

    From high-capacity, inexpensive hard drives to mag-lev trains, recent achievements in magnetic materials research have made the dreams of a few decades ago reality. The objective of Handbook of Advanced Magnetic Materials is to provide a timely, comprehensive review of recent progress in magnetic materials research. This broad yet detailed reference consists of four volumes: 1.) Nanostructured advanced magnetic materials, 2.) Characterization and simulation of advanced magnetic materials, 3.) Processing of advanced magnetic materials, and 4.) Properties and applications of advanced magnetic materials The first volume documents and explains recent development of nanostructured magnetic materials, emphasizing size effects. The second volume provides a comprehensive review of both experimental methods and simulation techniques for the characterization of magnetic materials. The third volume comprehensively reviews recent developments in the processing and manufacturing of advanced magnetic materials. With the co...

  11. Going Wild: Lessons from Naturally Occurring T-Lymphotropic Lentiviruses

    OpenAIRE

    VandeWoude, Sue; Apetrei, Cristian

    2006-01-01

    Over 40 nonhuman primate (NHP) species harbor species-specific simian immunodeficiency viruses (SIVs). Similarly, more than 20 species of nondomestic felids and African hyenids demonstrate seroreactivity against feline immunodeficiency virus (FIV) antigens. While it has been challenging to study the biological implications of nonfatal infections in natural populations, epidemiologic and clinical studies performed thus far have only rarely detected increased morbidity or impaired fecundity/sur...

  12. Evaluation of the prevalence of lymphotropic hepatitis viruses in ...

    African Journals Online (AJOL)

    SAra

    3Haematology Research Center and Bone marrow Transplant Unit, Shiraz University of Medical Sciences-Shiraz, ... studies, the rates and severity of clinical liver disease ..... Non-Hodgkin lymphoma: results of the NCI-SEER multi-center case.

  13. Negative magnetic relaxation in superconductors

    Directory of Open Access Journals (Sweden)

    Krasnoperov E.P.

    2013-01-01

    Full Text Available It was observed that the trapped magnetic moment of HTS tablets or annuli increases in time (negative relaxation if they are not completely magnetized by a pulsed magnetic field. It is shown, in the framework of the Bean critical-state model, that the radial temperature gradient appearing in tablets or annuli during a pulsed field magnetization can explain the negative magnetic relaxation in the superconductor.

  14. Magnetic cooling at Risoe DTU

    OpenAIRE

    Nielsen, Kaspar Kirstein; Bjørk, Rasmus; Jensen, Jesper Buch; Bahl, Christian Robert Haffenden; Pryds, Nini; Smith, Anders; Nordentoft, Anders; Hattel, Jesper Henri

    2009-01-01

    Magnetic refrigeration at room temperature is of great interest due to a long-term goal of making refrigeration more energy-efficient, less noisy and free of any environmentally hostile materials. A refrigerator utilizing an active magnetic regenerator (AMR) is based on the magnetocaloric effect, which manifests itself as a temperature change in magnetic materials when subjected to a varying magnetic field. In this work we present the current state of magnetic refrigeration research at Risoe ...

  15. EDITORIAL: Ultrafast magnetization processes

    Science.gov (United States)

    Hillebrands, Burkard

    2008-09-01

    This Cluster Issue of Journal of Physics D: Applied Physics is devoted to ultrafast magnetization processes. It reports on the scientific yield of the Priority Programme 1133 'Ultrafast Magnetization Processes' which was funded by the Deutsche Forschungsgemeinschaft in the period 2002-2008 in three successive two-year funding periods, supporting research of 17-18 groups in Germany. Now, at the end of this Priority Programme, the members feel that the achievements made in the course of the programme merit communication to the international scientific community in a concerted way. Therefore, each of the projects of the last funding period presents a key result in a published contribution to this Cluster Issue. The purpose of the funding by a Priority Programme is to advance knowledge in an emerging field of research through collaborative networked support over several locations. Priority Programmes are characterized by their enhanced quality of research through the use of new methods and forms of collaboration in emerging fields, by added value through interdisciplinary cooperation, and by networking. The aim of the Priority Programme 1133 'Ultrafast Magnetization Processes' may be well characterized by the call for projects in June 2001 after the programme was approved by the Deutsche Forschungsgemeinschaft: 'The aim of the priority programme is the achievement of a basic understanding of the temporal evolution of fast magnetization processes in magnetically ordered films, multilayers and micro-structured systems. The challenge lies in the advancement of the field of ultrafast magnetization processes into the regime of a few femtoseconds to nanoseconds, a topic not yet well explored. A general aim is to understand the fundamental mechanisms needed for applications in ultrafast magneto-electronic devices. The fundamental topic to be addressed is the response of the magnetization of small structures upon the application of pulsed magnetic fields, laser pulses or

  16. Magnetic Nanocomposite Cilia Sensors

    KAUST Repository

    Alfadhel, Ahmed

    2016-07-19

    Recent progress in the development of artificial skin concepts is a result of the increased demand for providing environment perception such as touch and flow sensing to robots, prosthetics and surgical tools. Tactile sensors are the essential components of artificial skins and attracted considerable attention that led to the development of different technologies for mimicking the complex sense of touch in humans. This dissertation work is devoted to the development of a bioinspired tactile sensing technology that imitates the extremely sensitive hair-like cilia receptors found in nature. The artificial cilia are fabricated from permanent magnetic, biocompatible and highly elastic nanocomposite material, and integrated on a giant magneto-impedance magnetic sensor to measure the stray field. A force that bends the cilia changes the stray field and is therefore detected with the magnetic sensor, providing high performance in terms of sensitivity, power consumption and versatility. The nanocomposite is made of Fe nanowires (NWs) incorporated into polydimethylsiloxane (PDMS). Fe NWs have a high remanent magnetization, due the shape anisotropy; thus, they are acting as permanent nano-magnets. This allows remote device operation and avoids the need for a magnetic field to magnetize the NWs, benefiting miniaturization and the possible range of applications. The magnetic properties of the nanocomposite can be easily tuned by modifying the NWs concentration or by aligning the NWs to define a magnetic anisotropy. Tactile sensors are realized on flexible and rigid substrates that can detect flow, vertical and shear forces statically and dynamically, with a high resolution and wide operating range. The advantage to operate the sensors in liquids and air has been utilized to measure flows in different fluids in a microfluidic channel. Various dynamic studies were conducted with the tactile sensor demonstrating the detection of moving objects or the texture of objects. Overall

  17. Magnetically textured ferrofluid in a non-magnetic matrix: Magnetic properties

    Indian Academy of Sciences (India)

    Mrudul Gadhvi; R V Upadhyay; Kinnari Parekh; R V Mehta

    2004-04-01

    Texturing of two different magnetic fluids were carried out in paraffin wax under the influence of an external magnetic field. The textured samples were characterized using magnetization measurement and a.c. susceptibility techniques. The results are discussed in the light of ratio of anisotropic energy to magnetic and thermal energies.

  18. Design Study Of Cyclotron Magnet With Permanent Magnet

    Science.gov (United States)

    Kim, Hyun Wook; Chai, Jong Seo

    2011-06-01

    Low energy cyclotrons for Positron emission tomography (PET) have been wanted for the production of radio-isotopes after 2002. In the low energy cyclotron magnet design, increase of magnetic field between the poles is needed to make a smaller size of magnet and decrease power consumption. The Permanent magnet can support this work without additional electric power consumption in the cyclotron. In this paper the study of cyclotron magnet design using permanent magnet is shown and also the comparison between normal magnet and the magnet which is designed with permanent magnet is shown. Maximum energy of proton is 8 MeV and RF frequency is 79.3 MHz. 3D CAD design was done by CATIA P3 V5 R18 [1] and the All field calculations had been performed by OPERA-3D TOSCA [2]. The self-made beam dynamics program OPTICY [3] is used for making isochronous field and other calculations.

  19. Solar Magnetic Flux Ropes

    Indian Academy of Sciences (India)

    Boris Filippov; Olesya Martsenyuk; Abhishek K. Srivastava; Wahab Uddin

    2015-03-01

    In the early 1990s, it was found that the strongest disturbances of the space–weather were associated with huge ejections of plasma from the solar corona, which took the form of magnetic clouds when moved from the Sun. It is the collisions of the magnetic clouds with the Earth's magnetosphere that lead to strong, sometimes catastrophic changes in space–weather. The onset of a coronal mass ejection (CME) is sudden and no reliable forerunners of CMEs have been found till date. The CME prediction methodologies are less developed compared to the methods developed for the prediction of solar flares. The most probable initial magnetic configuration of a CME is a flux rope consisting of twisted field lines which fill the whole volume of a dark coronal cavity. The flux ropes can be in stable equilibrium in the coronal magnetic field for weeks and even months, but suddenly they lose their stability and erupt with high speed. Their transition to the unstable phase depends on the parameters of the flux rope (i.e., total electric current, twist, mass loading, etc.), as well as on the properties of the ambient coronal magnetic field. One of the major governing factors is the vertical gradient of the coronal magnetic field, which is estimated as decay index (). Cold dense prominence material can be collected in the lower parts of the helical flux tubes. Filaments are, therefore, good tracers of the flux ropes in the corona, which become visible long before the beginning of the eruption. The perspectives of the filament eruptions and following CMEs can be estimated by a comparison of observed filament heights with calculated decay index distributions. The present paper reviews the formation of magnetic flux ropes, their stable and unstable phases, eruption conditions, and also discusses their physical implications in the solar corona.

  20. Rigidly connected magnetic lines: twisting and winding of magnetic lines

    Science.gov (United States)

    Prasad, G.

    2017-10-01

    The dynamical process of magnetic flux variation in a fluid's stream tube is described by constructing 1+1+ (2) decomposition of the gradient of fluid's 4-velocity. The necessary and sufficient conditions are obtained for a spacelike congruence to be a congruence of rigidly connected spacelike curves. The evolution of magnetic flux in a magnetic tube is explored under the assumptions that magnetic lines are rigidly connected and the chemical potential of the fluid is constant along a magnetic tube. The interplay between magnetic and stream tubes is demonstrated. It is shown that the growth of magnetic energy in a magnetic tube cannot exceed to that of a stream tube. It is found that the proper time variation of twist of magnetic lines is caused by gravitation inside a neutron star if magnetic lines are rigidly connected and charge neutrality condition holds. Helmholtz-like magnetic vorticity flux conservation in a magnetic tube constituted by rigidly connected geodetic magnetic lines is derived under the assumption that the charge neutrality condition holds. It is shown that the winding of frozen-in poloidal magnetic field due to differential rotation requires meridional circulation in an axisymmetric stationary hydromagnetic configuration.

  1. Dynamic interaction between rotor and axially-magnetized passive magnetic bearing considering magnetic eccentricity

    DEFF Research Database (Denmark)

    Enemark, Søren; Santos, Ilmar

    2014-01-01

    Passive magnetic bearings are known due to the excellent characteristics in terms of friction and no requirement of additional energy sources to work. However, passive magnetic bearings do not provide damping, are not stable and, depending on their design, may also introduce magnetic eccentricity....... Such magnetic eccentricities are generated by discrepancies in magnet fabrication. In this framework the main focus of the work is the theoretical as well as experimental investigation of the nonlinear dynamics of a rotor-bearing system with strong emphasis on the magnetic eccentricities and non......-linear stiffness. In this investigation passive magnetic bearings using axially- aligned neodymium cylinder magnets are investigated. The cylinder magnets are axially magnetised for rotor as well as bearings. Compared to bearings with radial magnetisation, the magnetic stiffness of axially-aligned bearings...

  2. Influence of magnetic domain walls and magnetic field on the thermal conductivity of magnetic nanowires.

    Science.gov (United States)

    Huang, Hao-Ting; Lai, Mei-Feng; Hou, Yun-Fang; Wei, Zung-Hang

    2015-05-13

    We investigated the influence of magnetic domain walls and magnetic fields on the thermal conductivity of suspended magnetic nanowires. The thermal conductivity of the nanowires was obtained using steady-state Joule heating to measure the change in resistance caused by spontaneous heating. The results showed that the thermal conductivity coefficients of straight and wavy magnetic nanowires decreased with an increase in the magnetic domain wall number, implying that the scattering between magnons and domain walls hindered the heat transport process. In addition, we proved that the magnetic field considerably reduced the thermal conductivity of a magnetic nanowire. The influence of magnetic domain walls and magnetic fields on the thermal conductivity of polycrystalline magnetic nanowires can be attributed to the scattering of long-wavelength spin waves mediated by intergrain exchange coupling.

  3. Performance of repulsive type magnetic bearing system under nonuniform magnetization of permanent magnet

    OpenAIRE

    Ohji, T.; Mukhopadhyay, S. C.; Iwahara, Masayoshi; Yamada, Sotoshi

    2000-01-01

    Permanent magnet bearing system utilizes the repulsive forces between the stator and rotor permanent magnets (PM) for the levitation of the system and it results a simplified axial control scheme. A repulsive type magnetic bearing system based on the above principle was fabricated in our laboratory. Material characteristics and the configuration of the permanent magnets are the central component for this type of bearing system. Due to aging or as both the magnets are repelling each other, the...

  4. Forces Between a Permanent Magnet and a Soft Magnetic Plate

    DEFF Research Database (Denmark)

    Beleggia, Marco; Vokoun, David; De Graef, Marc

    2012-01-01

    Forces between a hard/permanent magnet of arbitrary shape and an ideally soft magnetic plate in close proximity are derived analytically from the image method applied to magnetostatics. We found that the contact force, defined as the force required to detach the hard magnet from the plate......, coincides with that between two identical touching permanent magnets. Furthermore, if the hard and the soft magnets are displaced by some amount, their attraction equals that between two identical permanent magnets displaced by twice that amount. Experimental results are presented that validate...

  5. Comparing superconducting and permanent magnets for magnetic refrigeration

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Nielsen, Kaspar Kirstein; Bahl, C. R. H.

    2016-01-01

    We compare the cost of a high temperature superconducting (SC) tape-based solenoidwith a permanent magnet (PM) Halbach cylinder for magnetic refrigeration.Assuming a five liter active magnetic regenerator volume, the price of each type ofmagnet is determined as a function of aspect ratio of the r......We compare the cost of a high temperature superconducting (SC) tape-based solenoidwith a permanent magnet (PM) Halbach cylinder for magnetic refrigeration.Assuming a five liter active magnetic regenerator volume, the price of each type ofmagnet is determined as a function of aspect ratio...

  6. AA quadrupole magnet

    CERN Multimedia

    1980-01-01

    Focusing magnet used for the AA (antiproton accumulator).Making an antiproton beam took a lot of time and effort. Firstly, protons were accelerated to an energy of 26 GeV in the PS and ejected onto a metal target. From the spray of emerging particles, a magnetic horn picked out 3.6 GeV antiprotons for injection into the AA through a wide-aperture focusing quadrupole magnet. For a million protons hitting the target, just one antiproton was captured, 'cooled' and accumulated. It took 3 days to make a beam of 3 x 10^11 - three hundred thousand million - antiprotons. About focusing magnets (quadrupoles): Quadrupole magnets are needed to focus the particle beams and squeeze them so that more particles collide when the beams cross. Particle beams are stored for about 10 hours in the LHC. During this time, the particles make four hundred million revolutions around the machine, travelling a distance equivalent to the diameter of the solar system.

  7. Turbulent General Magnetic Reconnection

    CERN Document Server

    Eyink, Gregory L

    2014-01-01

    Plasma flows with an MHD-like turbulent inertial range, such as the solar wind, require a generalization of General Magnetic Reconnection (GMR) theory. We introduce the slip-velocity source vector, which gives the rate of development of slip velocity per unit arc length of field line. The slip source vector is the ratio of the curl of the non ideal electric field in the Generalized Ohm's Law and the magnetic field strength. It diverges at magnetic nulls, unifying GMR with magnetic null-point reconnection. Only under restrictive assumptions is the slip velocity related to the gradient of the quasi potential (integral of parallel electric field along field lines). In a turbulent inertial range the curl becomes extremely large while the parallel component is tiny, so that line slippage occurs even while ideal MHD becomes accurate. The resolution of this paradox is that ideal MHD is valid for a turbulent inertial-range only in a weak sense which does not imply magnetic line freezing. The notion of weak solution i...

  8. Magnetically Coupled Calorimeters

    Science.gov (United States)

    Bandler, Simon

    2011-01-01

    Calorimeters that utilize the temperature sensitivity of magnetism have been under development for over 20 years. They have targeted a variety of different applications that require very high resolution spectroscopy. I will describe the properties of this sensor technology that distinguish it from other low temperature detectors and emphasize the types of application to which they appear best suited. I will review what has been learned so far about the best materials, geometries, and read-out amplifiers and our understanding of the measured performance and theoretical limits. I will introduce some of the applications where magnetic calorimeters are being used and also where they are in development for future experiments. So far, most magnetic calorimeter research has concentrated on the use of paramagnets to provide temperature sensitivity; recent studies have also focused on magnetically coupled calorimeters that utilize the diamagnetic response of superconductors. I will present some of the highlights of this research, and contrast the properties of the two magnetically coupled calorimeter types.

  9. Extraterrestrial magnetic minerals

    Science.gov (United States)

    Pechersky, D. M.; Markov, G. P.; Tsel'movich, V. A.; Sharonova, Z. V.

    2012-07-01

    Thermomagnetic and microprobe analyses are carried out and a set of magnetic characteristics are measured for 25 meteorites and 3 tektites from the collections of the Vernadsky Geological Museum of the Russian Academy of Sciences and Museum of Natural History of the North-East Interdisciplinary Science Research Institute, Far Eastern Branch of the Russian Academy of Sciences. It is found that, notwithstanding their type, all the meteorites contain the same magnetic minerals and only differ by concentrations of these minerals. Kamacite with less than 10% nickel is the main magnetic mineral in the studied samples. Pure iron, taenite, and schreibersite are less frequent; nickel, various iron spinels, Fe-Al alloys, etc., are very rare. These minerals are normally absent in the crusts of the Earth and other planets. The studied meteorites are more likely parts of the cores and lower mantles of the meteoritic parent bodies (the planets). Uniformity in the magnetic properties of the meteorites and the types of their thermomagnetic (MT) curves is violated by secondary alterations of the meteorites in the terrestrial environment. The sediments demonstrate the same monotony as the meteorites: kamacite is likely the only extraterrestrial magnetic mineral, which is abundant in sediments and associated with cosmic dust. The compositional similarity of kamacite in iron meteorites and in cosmic dust is due to their common source; the degree of fragmentation of the material of the parent body is the only difference.

  10. Magnetic binary nanofillers

    Energy Technology Data Exchange (ETDEWEB)

    Morales Mendoza, N. [INQUIMAE, CONICET-UBA, Ciudad Universitaria, Pab2, (C1428EHA) Bs As (Argentina); LPyMC, Dep. De Fisica, FCEN-UBA and IFIBA -CONICET, Ciudad Universitaria, Cap. Fed. (Argentina); Goyanes, S. [LPyMC, Dep. De Fisica, FCEN-UBA and IFIBA -CONICET, Ciudad Universitaria, Cap. Fed. (Argentina); Chiliotte, C.; Bekeris, V. [LBT, Dep. De Fisica, FCEN-UBA. Ciudad Universitaria, Pab1, C1428EGA CABA (Argentina); Rubiolo, G. [LPyMC, Dep. De Fisica, FCEN-UBA and IFIBA -CONICET, Ciudad Universitaria, Cap. Fed. (Argentina); Unidad de Actividad Materiales, CNEA, Av Gral. Paz 1499, San Martin (1650), Prov. de Bs As (Argentina); Candal, R., E-mail: candal@qi.fcen.uba.ar [INQUIMAE, CONICET-UBA, Ciudad Universitaria, Pab2, (C1428EHA) Bs As (Argentina); Escuela de Ciencia y Tecnologia, 3iA, Universidad de Gral. San Martin, San Martin, Prov. Bs As (Argentina)

    2012-08-15

    Magnetic binary nanofillers containing multiwall carbon nanotubes (MWCNT) and hercynite were synthesized by Chemical Vapor Deposition (CVD) on Fe/AlOOH prepared by the sol-gel method. The catalyst precursor was fired at 450 Degree-Sign C, ground and sifted through different meshes. Two powders were obtained with different particle sizes: sample A (50-75 {mu}m) and sample B (smaller than 50 {mu}m). These powders are composed of iron oxide particles widely dispersed in the non-crystalline matrix of aluminum oxide and they are not ferromagnetic. After reduction process the powders are composed of {alpha}-Fe nanoparticles inside hercynite matrix. These nanofillers are composed of hercynite containing {alpha}-Fe nanoparticles and MWCNT. The binary magnetic nanofillers were slightly ferromagnetic. The saturation magnetization of the nanofillers depended on the powder particle size. The nanofiller obtained from powder particles in the range 50-75 {mu}m showed a saturation magnetization 36% higher than the one formed from powder particles smaller than 50 {mu}m. The phenomenon is explained in terms of changes in the magnetic environment of the particles as consequence of the presence of MWCNT.

  11. Magnetoacoustic Sensing of Magnetic Nanoparticles.

    Science.gov (United States)

    Kellnberger, Stephan; Rosenthal, Amir; Myklatun, Ahne; Westmeyer, Gil G; Sergiadis, George; Ntziachristos, Vasilis

    2016-03-11

    The interaction of magnetic nanoparticles and electromagnetic fields can be determined through electrical signal induction in coils due to magnetization. However, the direct measurement of instant electromagnetic energy absorption by magnetic nanoparticles, as it relates to particle characterization or magnetic hyperthermia studies, has not been possible so far. We introduce the theory of magnetoacoustics, predicting the existence of second harmonic pressure waves from magnetic nanoparticles due to energy absorption from continuously modulated alternating magnetic fields. We then describe the first magnetoacoustic system reported, based on a fiber-interferometer pressure detector, necessary for avoiding electric interference. The magnetoacoustic system confirmed the existence of previously unobserved second harmonic magnetoacoustic responses from solids, magnetic nanoparticles, and nanoparticle-loaded cells, exposed to continuous wave magnetic fields at different frequencies. We discuss how magnetoacoustic signals can be employed as a nanoparticle or magnetic field sensor for biomedical and environmental applications.

  12. Replacement reactor to revolutionise magnets

    CERN Document Server

    Atkins, G

    2002-01-01

    Electric motors, hearing aids and magnetic resonance imaging are only some of the applications that will benefit from the first advances in magnets in a quarter of a century. Magnets achieve their characteristics when electrons align themselves to produce a unified magnetic field. Neutrons can probe these magnetic structures. The focus is not just on making more powerful magnets, but also identifying the characteristics that make magnets cheaper and easier for industry to manufacture. Staff from the ANSTO's Neutron Scattering Group have already performed a number of studies on the properties of magnets using using HIFAR, but the Replacement Research Reactor that will produce cold neutrons would allow scientists to investigate the atomic properties of materials with large molecules. A suite of equipment will enable studies at different temperatures, pressures and magnetic fields

  13. Magnetic Reconnection in Astrophysical Environments

    CERN Document Server

    Lazarian, A; Vishniac, E; Kowal, G

    2014-01-01

    Magnetic reconnection is a process that changes magnetic field topology in highly conducting fluids. Traditionally, magnetic reconnection was associated mostly with solar flares. In reality, the process must be ubiquitous as astrophysical fluids are magnetized and motions of fluid elements necessarily entail crossing of magnetic frozen in field lines and magnetic reconnection. We consider magnetic reconnection in realistic 3D geometry in the presence of turbulence. This turbulence in most astrophysical settings is of pre-existing nature, but it also can be induced by magnetic reconnection itself. In this situation turbulent magnetic field wandering opens up reconnection outflow regions, making reconnection fast. We discuss Lazarian \\& Vishniac (1999) model of turbulent reconnection, its numerical and observational testings, as well as its connection to the modern understanding of the Lagrangian properties of turbulent fluids. We show that the predicted dependences of the reconnection rates on the level of...

  14. Magnetic digital microfluidics - a review.

    Science.gov (United States)

    Zhang, Yi; Nguyen, Nam-Trung

    2017-03-14

    A digital microfluidic platform manipulates droplets on an open surface. Magnetic digital microfluidics utilizes magnetic forces for actuation and offers unique advantages compared to other digital microfluidic platforms. First, the magnetic particles used in magnetic digital microfluidics have multiple functions. In addition to serving as actuators, they also provide a functional solid substrate for molecule binding, which enables a wide range of applications in molecular diagnostics and immunodiagnostics. Second, magnetic digital microfluidics can be manually operated in a "power-free" manner, which allows for operation in low-resource environments for point-of-care diagnostics where even batteries are considered a luxury item. This review covers research areas related to magnetic digital microfluidics. This paper first summarizes the current development of magnetic digital microfluidics. Various methods of droplet manipulation using magnetic forces are discussed, ranging from conventional magnetic particle-based actuation to the recent development of ferrofluids and magnetic liquid marbles. This paper also discusses several new approaches that use magnetically controlled flexible substrates for droplet manipulation. In addition, we emphasize applications of magnetic digital microfluidics in biosensing and medical diagnostics, and identify the current limitations of magnetic digital microfluidics. We provide a perspective on possible solutions to close these gaps. Finally, the paper discusses the future improvement of magnetic digital microfluidics to explore potential new research directions.

  15. Obtaining Magnetic Properties of Meteorites Using Magnetic Scanner

    Science.gov (United States)

    Kletetschka, G.; Nabelek, L.; Mazanec, M.; Simon, K.; Hruba, J.

    2015-12-01

    Magnetic images of Murchison meteorite's and Chelyabinsk meteorite's thin section have been obtained from magnetic scanning system from Youngwood Science and Engineering (YSE) capable of resolving magnetic anomalies down to 10-3 mT range from about 0.3 mm distance between the probe and meteorite surface (resolution about 0.15 mm). Anomalies were produced repeatedly, each time after application of magnetic field pulse of varying amplitude and constant, normal or reversed, direction. This process resulted in both magnetizing and demagnetizing of the meteorite thin section, while keeping the magnetization vector in the plane of the thin section. Analysis of the magnetic data allows determination of coercivity of remanence (Bcr) for the magnetic sources in situ. Value of Bcr is critical for calculating magnetic forces applicable during missions to asteroids where gravity is compromised. Bcr was estimated by two methods. First method measured varying dipole magnetic field strength produced by each anomaly in the direction of magnetic pulses. Second method measured deflections of the dipole direction from the direction of magnetic pulses (Nabelek et al., 2015). Nabelek, L., Mazanec, M., Kdyr, S., and Kletetschka, G., 2015, Magnetic, in situ, mineral characterization of Chelyabinsk meteorite thin section: Meteoritics & Planetary Science.

  16. New ALPHA-2 magnet

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    On 21 June, members of the ALPHA collaboration celebrated the handover of the first solenoid designed for the ALPHA-2 experiment. The magnet has since been successfully installed and is working well.   Khalid Mansoor, Sumera Yamin and Jeffrey Hangst in front of the new ALPHA-2 solenoid. “This was the first of three identical solenoids that will be installed between now and September, as the rest of the ALPHA-2 device is installed and commissioned,” explains ALPHA spokesperson Jeffrey Hangst. “These magnets are designed to allow us to transfer particles - antiprotons, electrons and positrons - between various parts of the new ALPHA-2 device by controlling the transverse size of the particle bunch that is being transferred.” Sumera Yamin and Khalid Mansoor, two Pakistani scientists from the National Centre for Physics in Islamabad, came to CERN in February specifically to design and manufacture these magnets. “We had the chance to work on act...

  17. Cosmic magnetic fields

    CERN Document Server

    Kronberg, Philipp P

    2016-01-01

    Magnetic fields are important in the Universe and their effects contain the key to many astrophysical phenomena that are otherwise impossible to understand. This book presents an up-to-date overview of this fast-growing topic and its interconnections to plasma processes, astroparticle physics, high energy astrophysics, and cosmic evolution. The phenomenology and impact of magnetic fields are described in diverse astrophysical contexts within the Universe, from galaxies to the filaments and voids of the intergalactic medium, and out to the largest redshifts. The presentation of mathematical formulae is accessible and is designed to add insight into the broad range of topics discussed. Written for graduate students and researchers in astrophysics and related disciplines, this volume will inspire readers to devise new ways of thinking about magnetic fields in space on galaxy scales and beyond.

  18. Skyrmions in magnetic materials

    CERN Document Server

    Seki, Shinichiro

    2016-01-01

    This brief reviews current research on magnetic skyrmions, with emphasis on formation mechanisms, observation techniques, and materials design strategies. The response of skyrmions, both static and dynamical, to various electromagnetic fields is also covered in detail. Recent progress in magnetic imaging techniques has enabled the observation of skyrmions in real space, as well as the analysis of their ordering manner and the details of their internal structure. In metallic systems, conduction electrons moving through the skyrmion spin texture gain a nontrivial quantum Berry phase, which provides topological force to the underlying spin texture and enables the current-induced manipulation of magnetic skyrmions. On the other hand, skyrmions in an insulator can induce electric polarization through relativistic spin-orbit interaction, paving the way for the control of skyrmions by an external electric field without loss of Joule heating. Because of its nanometric scale, particle nature, and electric controllabil...

  19. Magnetic hyperbolic optical metamaterials.

    Science.gov (United States)

    Kruk, Sergey S; Wong, Zi Jing; Pshenay-Severin, Ekaterina; O'Brien, Kevin; Neshev, Dragomir N; Kivshar, Yuri S; Zhang, Xiang

    2016-04-13

    Strongly anisotropic media where the principal components of electric permittivity or magnetic permeability tensors have opposite signs are termed as hyperbolic media. Such media support propagating electromagnetic waves with extremely large wave vectors exhibiting unique optical properties. However, in all artificial and natural optical materials studied to date, the hyperbolic dispersion originates solely from the electric response. This restricts material functionality to one polarization of light and inhibits free-space impedance matching. Such restrictions can be overcome in media having components of opposite signs for both electric and magnetic tensors. Here we present the experimental demonstration of the magnetic hyperbolic dispersion in three-dimensional metamaterials. We measure metamaterial isofrequency contours and reveal the topological phase transition between the elliptic and hyperbolic dispersion. In the hyperbolic regime, we demonstrate the strong enhancement of thermal emission, which becomes directional, coherent and polarized. Our findings show the possibilities for realizing efficient impedance-matched hyperbolic media for unpolarized light.

  20. Rock and mineral magnetism

    CERN Document Server

    O’Reilly, W

    1984-01-01

    The past two decades have witnessed a revolution in the earth sciences. The quantitative, instrument-based measurements and physical models of. geophysics, together with advances in technology, have radically transformed the way in which the Earth, and especially its crust, is described. The study of the magnetism of the rocks of the Earth's crust has played a major part in this transformation. Rocks, or more specifically their constituent magnetic minerals, can be regarded as a measuring instrument provided by nature, which can be employed in the service of the earth sciences. Thus magnetic minerals are a recording magnetometer; a goniometer or protractor, recording the directions of flows, fields and forces; a clock; a recording thermometer; a position recorder; astrain gauge; an instrument for geo­ logical surveying; a tracer in climatology and hydrology; a tool in petrology. No instrument is linear, or free from noise and systematic errors, and the performance of nature's instrument must be assessed and ...