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Sample records for active magnetic regenerator

  1. An active magnetic regenerator device

    2015-01-01

    A rotating active magnetic regenerator (AMR) device comprising two or more regenerator beds, a magnet arrangement and a valve arrangement. The valve arrangement comprises a plurality of valve elements arranged substantially immovably with respect to the regenerator beds along a rotational direction...

  2. Demagnetizing fields in active magnetic regenerators

    Nielsen, Kaspar Kirstein; Bahl, Christian R.H.; Smith, Anders

    2014-01-01

    A magnetic material in an externally applied magnetic field will in general experience a spatially varying internal magnetic field due to demagnetizing effects. When the performance of active magnetic regenerators (AMRs) is evaluated using numerical models the internal field is often assumed to be...... is in general both a function of the overall shape of the regenerator and its morphology (packed particles, parallel plates etc.) as well as the magnetization of the material. Due to the pronounced temperature dependence of the magnetization near the Curie temperature, the demagnetization field is...

  3. Development of an active magnetic regenerator for space applications

    Chen, Weibo

    2014-07-01

    This paper discusses the design of a micromachined regenerator in an Active Magnetic Regenerative Refrigeration (AMRR) system for space applications. The AMRR system is designed to provide continuous remote/distributed cooling at about 2 K and reject heat at temperatures of about 15 K. This paper first discusses the general thermal and fluid performance requirements for an AMRR regenerator, a unique structured bed configuration that enables the regenerator to meet these requirements, and its thermal and fluid performance based on numerical analyses. The paper then discusses the general design consideration for the magnetic field driving the regenerator for optimal thermal performance, and the analysis processes to optimize the variation rate of the magnetic field in an actual superconducting magnet during the isothermal processes of the AMRR cycle to enhance the performance of an actual regenerator. The paper finally presents the thermal performance of the regenerator from such iterative design optimization processes.

  4. Improved modelling of a parallel plate active magnetic regenerator

    Engelbrecht, Kurt; Tušek, J.; Nielsen, Kaspar Kirstein;

    2013-01-01

    Much of the active magnetic regenerator (AMR) modelling presented in the literature considers only the solid and fluid domains of the regenerator and ignores other physical effects that have been shown to be important, such as demagnetizing fields in the regenerator, parasitic heat losses and fluid...... flow maldistribution in the regenerator. This paper studies the effects of these loss mechanisms and compares theoretical results with experimental results obtained on an experimental AMR device. Three parallel plate regenerators were tested, each having different demagnetizing field characteristics...

  5. Experimental Studies with an Active Magnetic Regenerating Refrigerator

    Eriksen, Dan; Engelbrecht, Kurt; Bahl, Christian;

    2015-01-01

    Experimental results for an active magnetic regenerator (AMR) are presented. The focus is on whether or not it pays off to partly substitute soft magnetic material with non-magnetic insulation in a flux-conducting core in the magnet system. Such a substitution reduces losses due to heat conductio...

  6. Dimensionless numerical model for simulation of active magnetic regenerator refrigerator

    Sarlah, A.; Poredos, A. [Faculty of Mechanical Engineering, University of Ljubljana, Askerceva 6, SI-1000 Ljubljana (Slovenia)

    2010-09-15

    In order to obtain a better reliability, consistency and accuracy of results obtained with a numerical simulation of an AMRR (active magnetic regenerator refrigerator), a dimensionless numerical model was developed, which can equally be used for determination of regenerator's heat transfer coefficient and simulation of passive heat regenerators or AMRR operation. Regenerator's heat transfer coefficient {alpha}{sub f}, is a crucial input parameter in the simulation of AMRR operation and has a primal effect on the outcome of a solution. This paper deals with a derived dimensionless model and discusses errors involved when using different models for heat transfer coefficient and AMRR operation simulation. (author)

  7. Numerical modeling and analysis of the active magnetic regenerator

    Nielsen, Kaspar Kirstein

    In this thesis the active magnetic regenerator (AMR) is analyzed using various numerical tools and experimental devices. A 2-dimensional transient numerical model of the AMR is developed and implemented and it is used to investigate the in uence of a range of parameters on the performance of the...... investigated using the numerical AMR model. The results show indeed that the performance may be enhanced signicantly and it may thus be concluded that the performance of the AMR is dependent on a vast number of parameters (material composition, magnetic eld source, regenerator geometry, regenerator eciency...... AMR. The model simulates a regenerator made of parallel plates. The operating parameters, such as uid ow rates, thermal utilization, magnetocaloric properties etc. are varied as are geometric properties such as plate and channel thickness, regenerator length and porosity. In this way the performance...

  8. Exploring the efficiency potential for an active magnetic regenerator

    Eriksen, Dan; Engelbrecht, Kurt; Haffenden Bahl, Christian Robert;

    2016-01-01

    A novel rotary state of the art active magnetic regenerator refrigeration prototype was used in an experimental investigation with special focus on efficiency. Based on an applied cooling load, measured shaft power, and pumping power applied to the active magnetic regenerator, a maximum second......-law efficiency of 18% was obtained at a cooling load of 81.5 W, resulting in a temperature span of 15.5 K and a coefficient of performance of 3.6. A loss analysis is given, based on measured pumping power and shaft power together with theoretically estimated regenerator presssure drop. It is shown that......, especially for the pressure drop, significant improvements can be made to the machine. However, a large part of the losses may be attributed to regenerator irreversibilities. Considering these unchanged, an estimated upper limit to the second-law efficiency of 30% is given by eliminating parasitic losses and...

  9. A numerical analysis of a reciprocating Active Magnetic Regenerator with a parallel-plate regenerator geometry

    Petersen, Thomas Frank; Pryds, Nini; Smith, Anders;

    2007-01-01

    transfer equations for the regenerator and the fluid. The model is implemented using the Finite Element Method. The model can be used to study both transient and steady-state phenomena in the AMR for any ratio of regenerator to fluid heat capacity. Results on the AMR performance for different design......We have developed a two-dimensional model of a reciprocating Active Magnetic Regenerator(AMR) with a regenerator made of parallel plates arranged in a stack configuration. The time dependent,two-dimensional model solves the Navier-Stokes equations for the heat transfer fluid and the coupled heat...

  10. Experimental results for a novel rotary active magnetic regenerator

    Engelbrecht, Kurt; Eriksen, Dan; Bahl, Christian; Bjørk, Rasmus; Geyti, Jørgen; Lozano, Jaime; Nielsen, Kaspar Kirstein; Saxild, Finn B.; Smith, Anders; Pryds, Nini

    2012-01-01

    Active magnetic regenerator (AMR) refrigerators represent an alternative to vapor compression technology and have great potential in realizing cooling devices with high efficiency, which are highly desirable for a broad range of applications. The technology relies on the magnetocaloric effect in a...

  11. Numerical analysis of a reciprocating active magnetic regenerator

    A time-dependent, two-dimensional mathematical model of a configuration system for magnetic refrigeration has been developed, based on a reciprocating active magnetic regenerator operating at room temperature. The model's geometry is made of parallel plates of magnetocaloric material separated by microchannels. Through the microchannels, the flow of a heat transfer fluid has also been simulated. Water has been used as heat transfer fluid and as magnetocaloric material we have used the benchmark material gadolinium. The heat transfer inside the regenerator and the fluid flow are modelled separately and the magnetocaloric effect is taken into account by the inclusion of a variable source term in the energy equation. The model simulates the steps of the active magnetic regenerative refrigeration cycle and evaluates the performance in terms of cooling load, COP, temperature span and pressure drop for the parallel-plate configuration. The model has been validated by comparing the numerical results with the results obtained from an experimental device made by a partner. This parametric study allows us to identify the most important characteristics that have a significant influence on the thermal behaviour of the active magnetic regenerator. Several simulation results are discussed and some optimal solutions are presented. - Highlights: • We have developed a 2D model of an active magnetic regenerator. • The MCE is included as a source term with data from experimental measurements. • A validation of the model with experimental data is included. • We analysed the temperature span, the cooling power, the COP and the pressure drop of the system

  12. Numerical Modeling of Multi-Material Active Magnetic Regeneration

    Nielsen, Kaspar Kirstein; Engelbrecht, Kurt; Bahl, Christian Robert Haffenden;

    2009-01-01

    Magnetic refrigeration is a potentially environmentally-friendly alternative to vapour compression technology that is presented in this paper. The magnetocaloric effect in two magnetocaloric compounds in the La(Fe,Co,Si)13 series is presented in terms of their adiabatic temperature change and the...... specific heat as a function of temperature at constant magnetic field. A 2.5-dimensional numerical model of an active magnetic regenerative (AMR) refrigerator device is presented. The experimental AMR located at Risø DTU has been equipped with a parallel-plate based regenerator made of the two materials....... Experimental zero heat-load temperature spans are presented for different operating conditions and the results are compared to predictions of the numerical model. It is concluded that the model reproduces the experimental tendencies and when including thermal parasitic losses to ambient and the predictions...

  13. Effects of flow balancing on active magnetic regenerator performance

    Eriksen, Dan; Engelbrecht, Kurt; Bahl, Christian;

    2016-01-01

    Experiments with a recently constructed rotary multi-bed active magnetic regnenerator (AMR) prototype have revealed strong impacts on the temperature span from variations in the resistances of the flow channels carrying heat transfer fluid in and out of the regenerator beds. In this paper we show...... through numerical modeling how unbalanced flow in the beds decreases the cooling power and COP for a dual bed device. Furthermore, it is shown how resistance variations in multi-bed devices give rise to unbalanced flow in the individual beds and how this decreases cooling powers and COPs of the machines...

  14. The influence of the magnetic field on the performance of an active magnetic regenerator (AMR)

    Bjørk, Rasmus; Engelbrecht, Kurt

    2011-01-01

    The influence of the time variation of the magnetic field, termed the magnetic field profile, on the performance of a magnetocaloric refrigeration device using the active magnetic regeneration (AMR) cycle is studied for a number of process parameters for both a parallel plate and packed bed...... regenerator using a numerical model. The cooling curve of the AMR is shown to be almost linear far from the Curie temperature of the magnetocaloric material. It is shown that a magnetic field profile that is 10% of the cycle time out of sync with the flow profile leads to a drop in both the maximum...

  15. A modeling study on the geometry of active magnetic regenerator

    Numazawa, Takenori; Mastumoto, Koichi; Yanagisawa, Yoshinori; Nakagome, Hideki

    2012-06-01

    Magnetic refrigeration technology needs further development not just by the improvement of magnetocaloric properties but also the optimization of the cooling system design. One of the important problems in the cooling system design is the geometry of regenerator for the efficient heat transfer between magnetic material and fluid which is the major loss mechanism in cooling system. Two kinds of regenerators are widely used. One is flat plate regenerator which can offer the best heat transfer to pressure drop ratio [2] for common regenerator design; another is porous media regenerator which can obtain a large temperature span for the good heat transfer surface. But until now, only a few research papers actually study the regenerator geometry. This paper focuses on the influence of regenerator geometry to the performance of AMR system. The 1 dimension flat plat model and porous media model have been constructed and compared with entropy generation, cooling capacity, coefficient of performance by changing plate thickness and sphere size at frequency 0.25Hz, 0.5Hz, 1, aspect ratio 2, 7, 14. The result shows that the optimized sphere size will be around 0.2mm to 0.3mm. On the other hand, 0.1mm to 0.2mm thickness plate will be more efficient. Compared the 2 models, flat plate model can get a smaller entropy generation and achieve a higher cooling capacity.

  16. 2-dimensional numerical modeling of active magnetic regeneration

    Nielsen, Kaspar Kirstein; Pryds, Nini; Smith, Anders;

    2009-01-01

    Various aspects of numerical modeling of Active Magnetic Regeneration (AMR) are presented. Using a 2-dimensional numerical model for solving the unsteady heat transfer equations for the AMR system, a range of physical effects on both idealized and non-idealized AMR are investigated. The modeled...... system represents a linear, parallel-plate based AMR. The idealized version of the model is able to predict the theoretical performance of AMR in terms of cooling power and temperature span. This is useful to a certain extent, but a model reproducing experiments to a higher degree is desirable. Therefore...... physical effects such as thermal parasitic losses have been included. Furthermore, experimentally found magnetocaloric properties are used when available, since the commonly used mean field model can be too idealized and is not always able to determine the magnetocaloric effect accurately. In the present...

  17. The influence of the magnetic field on the performance of an active magnetic regenerator (AMR)

    Bjørk, R

    2014-01-01

    The influence of the time variation of the magnetic field, termed the magnetic field profile, on the performance of a magnetocaloric refrigeration device using the active magnetic regeneration (AMR) cycle is studied for a number of process parameters for both a parallel plate and packed bed regenerator using a numerical model. The cooling curve of the AMR is shown to be almost linear far from the Curie temperature of the magnetocaloric material. It is shown that a magnetic field profile that is 10% of the cycle time out of sync with the flow profile leads to a drop in both the maximum temperature span and the maximum cooling capacity of 20-40\\% for both parallel plate and packed bed regenerators. The maximum cooling capacity is shown to depend very weakly on the ramp rate of the magnetic field. Reducing the temporal width of the high field portion of the magnetic field profile by 10% leads to a drop in maximum temperature span and maximum cooling capacity of 5-20%. An increase of the magnetic field from 1 T t...

  18. Experimental and modelling results of a parallel-plate based active magnetic regenerator

    Tura, A.; Nielsen, Kaspar Kirstein; Rowe, A.

    2012-01-01

    The performance of a permanent magnet magnetic refrigerator (PMMR) using gadolinium parallel plates is described. The configuration and operating parameters are described in detail. Experimental results are compared to simulations using an established twodimensional model of an active magnetic...... regenerator (AMR). In particular, the effect of geometric demagnetization in the regenerator is included in a simplified manner. The model and experimental data are in good agreement while the effect of demagnetization is seen to degrade the performance. It is concluded from the experiments that both thinner...

  19. An efficient numerical scheme for the simulation of parallel-plate active magnetic regenerators

    Torregrosa-Jaime, Bárbara; Corberán, José M.; Payá, Jorge;

    2015-01-01

    A one-dimensional model of a parallel-plate active magnetic regenerator (AMR) is presented in this work. The model is based on an efficient numerical scheme which has been developed after analysing the heat transfer mechanisms in the regenerator bed. The new finite difference scheme optimally...... combines explicit and implicit techniques in order to solve the one-dimensional conjugate heat transfer problem in an accurate and fast manner while ensuring energy conservation. The present model has been thoroughly validated against passive regenerator cases with an analytical solution. Compared to the...

  20. Two-dimensional mathematical model of a reciprocating room-temperature Active Magnetic Regenerator

    Petersen, Thomas Frank; Pryds, Nini; Smith, Anders;

    2008-01-01

    A time-dependent, two-dimensional mathematical model of a reciprocating Active Magnetic Regenerator (AMR) operating at room-temperature has been developed. The model geometry comprises a regenerator made of parallel plates separated by channels of a heat transfer fluid and a hot as well as a cold...... heat exchanger. The model simulates the different steps of the AMR refrigeration cycle and evaluates the performance in terms of refrigeration capacity and temperature span between the two heat exchangers. The model was used to perform an analysis of an AMR with a regenerator made of gadolinium...

  1. Design and experimental tests of a rotary active magnetic regenerator prototype

    Eriksen, Dan; Engelbrecht, Kurt; Bahl, Christian;

    2015-01-01

    transfer fluid flow and an inhomogenous time-varying magnetic field in the individual regenerator beds has been used in the design process. For one operating point a COP of 3.1 at a temperature span of 10.2 K and a cooling power of 103Wwere measured. Major issues limiting the performance have been......A rotary active magnetic regenerator (AMR) prototype with efficiency and compact design as focus points has been designed and built. The main objective is to demonstrate improved efficiency for rotary devices by reducing heat leaks from the environment and parasitic mechanical work losses while...... optimizing the utilization of the magnetized volume. Heat transfer calculations combined with 1D AMR modeling have revealed the necessity for an insulating air gap between magnet and regenerator when designing for high efficiency. 2D finite difference AMR modeling capturing the interplay between heat...

  2. Study of geometries of active magnetic regenerators for room temperature magnetocaloric refrigeration

    Lei, Tian; Engelbrecht, Kurt; Nielsen, Kaspar Kirstein;

    2016-01-01

    Room temperature magnetic refrigeration has attracted substantial attention during the past decades and continuing to increase the performance of active magnetic regenerators (AMR) is of great interest. Optimizing the regenerator geometry and related operating parameters is a practical and...... effective way to obtain the desired cooling performance. To investigate how to choose and optimize the AMR geometry, a quantitative study is presented by simulations based on a one-dimensional (1D) numerical model. Correlations for calculating the friction factor and heat transfer coefficient are reviewed...... and chosen for modeling different geometries. Moreover, the simulated impacts of various parameters on the regenerator efficiency with a constant specific cooling capacity are presented. An analysis based on entropy production minimization reveals how those parameters affect the main losses occurring...

  3. Design Concepts for a Continuously Rotating Active Magnetic Regenerator

    Bahl, Christian Robert Haffenden; Engelbrecht, Kurt; Bjørk, Rasmus;

    2010-01-01

    Design considerations for a prototype magnetic refrigeration device with a continuously rotating AMR are presented. Building the AMR from stacks of elongated plates of the perovskite oxide material La0.67Ca0.33-xSrxMn1.05O3, gives both a low pressure drop and allows grading of the Curie temperatu...

  4. Performance of magnetic activated carbon composite as peroxymonosulfate activator and regenerable adsorbent via sulfate radical-mediated oxidation processes.

    Oh, Wen-Da; Lua, Shun-Kuang; Dong, Zhili; Lim, Teik-Thye

    2015-03-01

    Magnetic activated carbon composite (CuFe2O4/AC, MACC) was prepared by a co-precipitation-calcination method. The MACC consisted of porous micro-particle morphology with homogeneously distributed CuFe2O4 and possessed high magnetic saturation moment (8.1 emu g(-1)). The performance of MACC was evaluated as catalyst and regenerable adsorbent via peroxymonosulfate (PMS, Oxone(®)) activation for methylene blue (MB) removal. Optimum CuFe2O4/AC w/w ratio was 1:1.5 giving excellent performance and can be reused for at least 3 cycles. The presence of common inorganic ions, namely Cl(-) and NO3(-) did not exert significant influence on MB degradation but humic acid decreased the MB degradation rate. As a regenerable adsorbent, negligible difference in regeneration efficiency was observed when a higher Oxone(®) dosage was employed but a better efficiency was obtained at a lower MACC loading. The factors hindering complete MACC regeneration are MB adsorption irreversibility and AC surface modification by PMS making it less favorable for subsequent MB adsorption. With an additional mild heat treatment (150 °C) after regeneration, 82% of the active sites were successfully regenerated. A kinetic model incorporating simultaneous first-order desorption, second-order adsorption and pseudo-first order degradation processes was numerically-solved to describe the rate of regeneration. The regeneration rate increased linearly with increasing Oxone(®):MACC ratio. The MACC could potentially serve as a catalyst for PMS activation and regenerable adsorbent. PMID:25463211

  5. Review on numerical modeling of active magnetic regenerators for room temperature applications

    Nielsen, Kaspar Kirstein; Tusek, Jaka; Engelbrecht, Kurt;

    2011-01-01

    The active magnetic regenerator (AMR) is an alternative refrigeration cycle with a potential gain of energy efficiency compared to conventional refrigeration techniques. The AMR poses a complex problem of heat transfer, fluid dynamics and magnetic fields, which requires detailed and robust modeling....... This paper reviews the existing numerical modeling of room temperature AMR to date. The governing equations, implementation of the magnetocaloric effect (MCE), fluid flow and magnetic field profiles, thermal conduction etc. are discussed in detail as is their impact on the AMR cycle. Flow channeling...... effects, hysteresis, thermal losses and demagnetizing fields are discussed and it is concluded that more detailed modeling of these phenomena is required to obtain a better understanding of the AMR cycle....

  6. Study of a magnetic refrigeration cycle by active regeneration between 15 and 4.2 kelvins

    Magnetic refrigeration with active regeneration cycles was realized on a test bench. From a hot source at 14K cold power near 20 mW is reached on liquid helium at 4.2 K. Efficiency of the cooling loop is around 0.20. Different geometries are tested and a part of observed physical phenomena are simulated with a numerical model. Interest of ferromagnetic cryogenic materials for the range 4-15 K is evidenced by measurement of thermomagnetic properties of europium sulfide

  7. 1-D transient numerical model of a regenerator in a novel sub Kelvin Active Magnetic Regenerative Refrigerator

    Jahromi, Amir E.; Miller, Franklin K.

    2016-03-01

    A sub Kelvin Active Magnetic Regenerative Refrigerator (AMRR) is being developed at the University of Wisconsin - Madison. This AMRR consists of two circulators, two regenerators, one superleak, one cold heat exchanger, and two warm heat exchangers. The circulators are novel non-moving part pumps that reciprocate a superfluid mixture of 4He-3He in the system. Heat from the mixture is removed within the two regenerators of this tandem system. An accurate model of the regenerators in this AMRR is necessary in order to predict the performance of these components, which in turn helps predicting the overall performance of the AMRR system. This work presents modeling methodology along with results from a 1-D transient numerical model of the regenerators of an AMRR capable of removing 2.5 mW at 850 mK at cyclic steady state.

  8. Influence of manganite powder grain size and Ag-particle coating on the magnetocaloric effect and the active magnetic regenerator performance

    Turcaud, J.A.; Neves Bez, Henrique; Ruiz-Trejo, E.;

    2015-01-01

    the active magnetic regenerator cycle using the silver decorated material in powder form. The regenerator performance is improved by the reduction of the powder grain size of the refrigerant which we attribute to improved thermal management due to increased surface to volume ratio. © 2015 Acta...

  9. Study of multi-layer active magnetic regenerators using magnetocaloric materials with first and second order phase transition

    Lei, Tian; Engelbrecht, Kurt; Nielsen, Kaspar Kirstein;

    2016-01-01

    magnetocaloric refrigerators (MCR) demonstrated the great potential for these materials, but a thorough study on the impact of the moderate adiabatic temperature change and strong temperature dependence of the magnetocaloric effect (MCE) is lacking. Besides, comparing active magnetic regenerators (AMR) using...... MCE are quantified and analyzed by using artificially built magnetocaloric properties. Then, based on measured magnetocaloric properties of La(Fe,Mn,Si)13H y and Gd, an investigation on how to layer typical FOPT and SOPT materials with different temperature spans is carried out. Moreover, the...

  10. The influence of the solid thermal conductivity on active magnetic regenerators

    Nielsen, Kaspar Kirstein; Engelbrecht, Kurt

    2012-01-01

    range of thermal conductivities, operating frequencies, a long and short regenerator, and finally a regenerator with a low and a high number of transfer units (NTU) regenerator. In this way the performance is mapped out and the impact of the thermal conductivity of the solid is probed. Modeling shows...

  11. Using a Linux Cluster for Parallel Simulations of an Active Magnetic Regenerator Refrigerator

    Petersen, T.F.; Pryds, N.; Smith, A.

    2006-01-01

    This paper describes the implementation of a Comsol Multiphysics model on a Linux computer Cluster. The Magnetic Refrigerator (MR) is a special type of refrigerator with potential to reduce the energy consumption of household refrigeration by a factor of two or more. To conduct numerical analysis...

  12. Organic solvent regeneration of granular activated carbon

    Cross, W. H.; Suidan, M. T.; Roller, M. A.; Kim, B. R.; Gould, J. P.

    1982-09-01

    The use of activated carbon for the treatment of industrial waste-streams was shown to be an effective treatment. The high costs associated with the replacement or thermal regeneration of the carbon have prohibited the economic feasibility of this process. The in situ solvent regeneration of activated carbon by means of organic solvent extraction was suggested as an economically alternative to thermal regeneration. The important aspects of the solvent regeneration process include: the physical and chemical characteristics of the adsorbent, the pore size distribution and energy of adsorption associated with the activated carbon; the degree of solubility of the adsorbate in the organic solvent; the miscibility of the organic solvent in water; and the temperature at which the generation is performed.

  13. Modelling and comparison studies of packed screen regenerators for active magnetocaloric refrigeration

    Lei, Tian; Engelbrecht, Kurt; Nielsen, Kaspar Kirstein;

    2014-01-01

    relatively large pressure drop and almost fixed porosity make loss reductions and further optimization challenging. This paper proposes and focuses on packed screen regenerators, which may exhibit lower pressure drop and equivalent heat transfer performance to packed sphere regenerators. A 1D AMR model is......In active magnetic regeneration (AMR) systems, not only the magnetocaloric properties of materials, but also the regenerator geometry plays an important role in the system performance. Packed sphere regenerators are often employed in existing prototypes, however, the characteristics such as...... improved and applied to simulate the regenerators. The performance of the new regenerators is studied and compared with that of the packed sphere regenerators. Possible fabrication methods of the packed screen regenerators are also discussed....

  14. Mathematical Modeling of Magnetic Regenerator Refrigeration Systems

    Salarvand, Navid

    2009-01-01

    ABSTRACT: Active magnetic regenerative refrigeration (AMRR) systems are designed based on magnetocaloric effect of some special solid materials, such as Gadolinium-Silicon-Germanium, Ferrum-Rhodium, etc. During the last three decades, a variety of cooling systems have been proposed using magnetic materials at room temperature. In this thesis, an AMRR system using FeRh as refrigerant is studied. For the simulation, a one-dimensional, time-varying mathematical model is developed. This model co...

  15. A Monolithic Perovskite Structure for Use as a Magnetic Regenerator

    Pryds, Nini; Clemens, Frank; Menon, Mohan; Nielsen, Pernille Hedemark; Brodersen, Karen; Bjørk, Rasmus; Bahl, Christian Robert Haffenden; Engelbrecht, Kurt; Nielsen, Kaspar Kirstein; Smith, Anders

    2011-01-01

    A La0.67Ca0.26Sr0.07Mn1.05O3 (LCSM) perovskite was prepared for the first time as a ceramic monolithic regenerator used in a regenerative magnetic refrigeration device. The parameters influencing the extrusion process and the performance of the regenerator, such as the nature of the monolith paste...

  16. Microwave-assisted regeneration of activated carbon.

    Foo, K Y; Hameed, B H

    2012-09-01

    Microwave heating was used in the regeneration of methylene blue-loaded activated carbons produced from fibers (PFAC), empty fruit bunches (EFBAC) and shell (PSAC) of oil palm. The dye-loaded carbons were treated in a modified conventional microwave oven operated at 2450 MHz and irradiation time of 2, 3 and 5 min. The virgin properties of the origin and regenerated activated carbons were characterized by pore structural analysis and nitrogen adsorption isotherm. The surface chemistry was examined by zeta potential measurement and determination of surface acidity/basicity, while the adsorptive property was quantified using methylene blue (MB). Microwave irradiation preserved the pore structure, original active sites and adsorption capacity of the regenerated activated carbons. The carbon yield and the monolayer adsorption capacities for MB were maintained at 68.35-82.84% and 154.65-195.22 mg/g, even after five adsorption-regeneration cycles. The findings revealed the potential of microwave heating for regeneration of spent activated carbons. PMID:22728787

  17. Experimental results for a magnetic refrigerator using three different types of magnetocaloric material regenerators

    Engelbrecht, Kurt; Bahl, Christian Robert Haffenden; Nielsen, Kaspar Kirstein

    2011-01-01

    refrigeration device for near room temperature applications, and it is driven by the magnetocaloric effect in the regenerator material. Several magnetocaloric materials with potential magnetic refrigeration applications have recently been developed and characterized; however, few of them have been tested in an...... experimental device. This paper compares the performance of three magnetocaloric material candidates for AMRs, La(Fe,Co,Si)13, (La,Ca,Sr)MnO3 and Gd, in an experimental active magnetic regenerator with a parallel plate geometry. The performance of single-material regenerators of each magnetocaloric material...... family were compared. In an attempt to improve system performance, graded two-material regenerators were made from two different combinations of La(Fe,Co,Si)13 compounds having different magnetic transition temperatures. One combination of the La(Fe,Co,Si)13 materials yielded a higher performance, while...

  18. A recyclable and regenerable magnetic chitosan absorbent for dye uptake.

    Zhao, Weifeng; Huang, Xuelian; Wang, Yilin; Sun, Shudong; Zhao, Changsheng

    2016-10-01

    A recyclable and regenerable magnetic polysaccharide absorbent for methylene blue (MB) removal was prepared by coating magnetic polyethyleneimine nanoparticles (PEI@MNPs) with sulfonated chitosan (SCS) and further cross-linked with glutaraldehyde. The driving force for coating is the electrostactic interaction between positively charged PEI and negatively charged SCS. Infrared spectra, zeta potential, thermal gravimetric analysis and X-ray diffraction demonstrated the successful synthesis of magnetic polysaccharide absorbent. The self-assembly of polysaccharide with magnetic nanopartices did not alter the saturation magnetization value of the absorbent confirmed by vibrating sample magnetometer. The nanoparticles showed fast removal (about 30min reached equilibrium) of MB. In particular, the removal ability of MB after desorption did not reduce, demonstrating an excellent regeneration ability. Our study provides new insights into utilizing polysaccharides for environmental remediation and creating advanced magnetic materials for various promising applications. PMID:27312630

  19. Magnetic field intensified bi-enzyme system with in situ cofactor regeneration supported by magnetic nanoparticles.

    Zheng, Muqing; Su, Zhiguo; Ji, Xiaoyuan; Ma, Guanghui; Wang, Ping; Zhang, Songping

    2013-10-20

    Efficient dynamic interactions among cofactor, enzymes and substrate molecules are of primary importance for multi-step enzymatic reactions with in situ cofactor regeneration. Here we showed for the first time that the above dynamic interactions could be significantly intensified by exerting an external alternating magnetic field on magnetic nanoparticles-supported multi-enzymatic system so that the inter-particle collisions due to Brownian motion of nanoparticles could be improved. To that end, a multienzyme system including glutamate dehydrogenase (GluDH), glucose dehydrogenase (GDH) and cofactor NAD(H) were separately immobilized on silica coated Fe3O4 magnetic nanoparticles with an average diameter of 105 nm, and the effect of magnetic field strength and frequency on the kinetics of the coupled bi-enzyme reaction was investigated. It was found that at low magnetic field frequency (25 Hz and 100 Hz), increasing magnetic field strength from 9.8 to 161.1 Gs led to only very slight increase in reaction rate of the coupled bi-enzyme reaction expressed by glucose consumption rate. At higher magnetic field of 200 Hz and 500 Hz, reaction rate increased significantly with increase of magnetic field strength. When the magnetic field frequency was kept at 500 Hz, the reaction rate increased from 3.89 μM/min to 8.11 μM/min by increasing magnetic field strength from 1.3 to 14.2 Gs. The immobilized bi-enzyme system also showed good reusability and stability in the magnetic field (500 Hz, 14.2 Gs), that about 46% of original activity could be retained after 33 repeated uses, accounting for totally 34 days continuous operation. These results demonstrated the feasibility in intensifying molecular interactions among magnetic nanoparticle-supported multienzymes by using nano-magnetic stirrer for efficient multi-step transformations. PMID:23756150

  20. Rapid microwave-assisted regeneration of magnetic carbon nanotubes loaded with p-nitrophenol

    Cui, Chunyue, E-mail: cuichunyue1977@163.com [School of Resource and Environment, Qingdao Agricultural University, Qingdao 266109 (China); Zheng, Qingzhu [School of Resource and Environment, Qingdao Agricultural University, Qingdao 266109 (China); Han, Yanhe [Department of Environmental Engineering, Beijing Institute of Petrochemical Technology, 19 Qingyuan North Road, Daxing District, Beijing 102617 (China); Xin, Yanjun [School of Resource and Environment, Qingdao Agricultural University, Qingdao 266109 (China)

    2015-08-15

    Highlights: • Magnetic CNTs material was successfully synthesized. • Magnetic CNTs have high fast adsorption rate and adsorption capacity. • Magnetic CNTs can be easily separated from the water by external magnetic field. • Magnetic CNTs can be recycled by MW irradiation regeneration. - Abstract: A novel magnetic carbon nanotubes (CNTs) adsorbent with good sorption, magnetic separability, and microwave (MW) regeneration properties was prepared successfully using thermal decomposition. The magnetic CNTs were characterized using transmission electron microscopy, energy dispersive X-ray, nitrogen adsorption (Brunauer–Emmett–Teller surface area), and X-ray diffraction and their magnetic properties were measured using a vibrating sample magnetometer. Magnetic nanoparticles (≈10 nm diameter) were dispersed uniformly on the CNTs with a magnetic CNTs surface area of 146.7 m{sup 2} g{sup −1} and a saturation magnetization of 21.11 emu g{sup −1}. When the magnetic CNTs were used in the sorption of p-nitrophenol, the equilibrium time was 20 min and the sorption isotherms fit the Freundlich isotherm well. The spent magnetic CNTs could be separated magnetically and be regenerated by MW irradiation. After six adsorption and MW regeneration cycles (at 850 W for 180 s), the adsorption capacity of the magnetic CNTs was higher than that of the virgin magnetic CNTs with a low carbon loss.

  1. Regeneration of waste sintered Nd-Fe-B magnets to fabricate anisotropic bonded magnets

    李现涛; 岳明; 刘卫强; 张东涛; 左铁镛

    2015-01-01

    The waste sintered Nd-Fe-B magnets were regenerated as magnetic powders via manually crushing (MC) or hydrogen de-crepitation (HD) to fabricate anisotropic bonded magnets. Effect of size distribution on the magnetic properties of the regenerated magnetic MC and HD powders was investigated. For the MC powders, as the particle size decreased, the remanence (Br) increased first, and then decreased again, while the coercivity (Hci) dropped monotonically. The powders with particle size in the range of 200–450μm possessed the best magnetic properties ofBr of 1.22 T andHci of 875.6 kA/m. The corresponding bonded magnet exhibited magnetic properties ofBr of 0.838 T,Hci of 940.9 kA/m, and (BH)max of 91.4 kJ/m3, respectively. On the other hand, the HD powders with particle size range of 200-450μm bore the best magnetic properties ofBr of 1.24 T andHci of 860.4 kA/m. Compared with magnetic proper-ties of the waste magnet, the powders retained 93.9% ofBr and 70.0% ofHci, respectively. The bonded magnet produced from HD powders possessedBr of 0.9 T,Hci of 841.4 kA/m, and (BH)max of 111.6 kJ/m3, indicating its good potential in practical applications.

  2. Regeneration tests of a room temperature magnetic refrigerator and heat pump

    Brown, G V

    2014-01-01

    A magnetic heat pump apparatus consisting of a solid magnetic refrigerant, gadolinium, and a liquid regenerator column of ethanol and water has been tested. Utilizing a 7T field, it produced a maximum temperature span of 80 K, and in separate tests, a lowest temperature of 241 K and a highest temperature of 328 K. Thermocouples, placed at intervals along the regenerator tube, permitted measurement of the temperature distribution in the regenerator fluid. No attempt was made to extract refrigeration from the device, but analysis of the temperature distributions shows that 34 watts of refrigeration was produced.

  3. Effect of high entropy magnetic regenerator materials on power of the GM refrigerator

    In previous work the authors have proved that heavy rare earth compounds with low magnetic transition temperature Tc are very useful as regenerator materials in low temperature range. Applying the magnetic material Er3Ni particles to the 2nd regenerator of the GM refrigerator, they were able to reach the 2 K range but could not obtain high refrigeration power at 4.2 K. This is thought to be due to the temperature dependence of the magnetic specific heat. They present here a method by which high refrigeration power is obtained at low temperature. The simplest means of obtaining high power is with a hybrid structure regenerator which is composed of two kinds of magnetic materials, high Tc and low Tc materials. Computer simulation and experiments were carried out to verify the superiority of the hybrid regenerator. The authors succeeded experimentally in obtaining the high power of ∼ 1.1 watt at 4.2 K. They will report other detailed results and discuss developing way of the magnetic regenerator in future

  4. Early exposure of rotating magnetic fields promotes central nervous regeneration in planarian Girardia sinensis.

    Chen, Qiang; Lin, Gui-Miao; Wu, Nan; Tang, Sheng-Wei; Zheng, Zhi-Jia; Lin, Marie Chia-Mi; Xu, Gai-Xia; Liu, Hao; Deng, Yue-Yue; Zhang, Xiao-Yun; Chen, Si-Ping; Wang, Xiao-Mei; Niu, Han-Ben

    2016-05-01

    Magnetic field exposure is an accepted safe and effective modality for nerve injury. However, it is clinically used only as a supplement or salvage therapy at the later stage of treatment. Here, we used a planarian Girardia sinensis decapitated model to investigate beneficial effects of early rotary non-uniform magnetic fields (RMFs) exposure on central nervous regeneration. Our results clearly indicated that magnetic stimulation induced from early RMFs exposure significantly promoted neural regeneration of planarians. This stimulating effect is frequency and intensity dependent. Optimum effects were obtained when decapitated planarians were cultured at 20 °C, starved for 3 days before head-cutting, and treated with 6 Hz 0.02 T RMFs. At early regeneration stage, RMFs exposure eliminated edema around the wound and facilitated subsequent formation of blastema. It also accelerated cell proliferation and recovery of neuron functionality. Early RMFs exposure up-regulated expression of neural regeneration related proteins, EGR4 and Netrin 2, and mature nerve cell marker proteins, NSE and NPY. These results suggest that RMFs therapy produced early and significant benefit in central nervous regeneration, and should be clinically used at the early stage of neural regeneration, with appropriate optimal frequency and intensity. Bioelectromagnetics. Bioelectromagnetics. 37:244-255, 2016. © 2016 Wiley Periodicals, Inc. PMID:27061713

  5. Cyclic dermal BMP signalling regulates stem cell activation during hair regeneration

    Plikus, M. V.; Mayer, J. A.; de La Cruz, D.; Baker, Ruth E.; Maini, P.K.; Maxson, R.; Chuong, C M

    2008-01-01

    In the age of stem cell engineering it is critical to understand how stem cell activity is regulated during regeneration. Hairs are mini-organs that undergo cyclic regeneration throughout adult life1, and are an important model for organ regeneration. Hair stem cells located in the follicle bulge2 are regulated by the surrounding microenvironment, or niche3. The activation of such stem cells is cyclic, involving periodic -catenin activity4, 5, 6, 7. In the adult mouse, regeneration occurs in ...

  6. Epigenetic regulation of satellite cell activation during muscle regeneration

    Dilworth, F Jeffrey; Blais, Alexandre

    2011-01-01

    Satellite cells are a population of adult muscle stem cells that play a key role in mediating muscle regeneration. Activation of these quiescent stem cells in response to muscle injury involves modulating expression of multiple developmentally regulated genes, including mediators of the muscle-specific transcription program: Pax7, Myf5, MyoD and myogenin. Here we present evidence suggesting an essential role for the antagonistic Polycomb group and Trithorax group proteins in the epigenetic ma...

  7. Comparison Between Dielectric Barrier Discharge Plasma and Ozone Regenerations of Activated Carbon Exhausted with Pentachlorophenol

    Qu, Guangzhou; Liang, Dongli; Qu, Dong; Huang, Yimei; Li, Jie

    2014-06-01

    In this study, two regeneration methods (dielectric barrier discharge (DBD) plasma and ozone (O3) regeneration) of saturated granular activated carbon (GAC) with pentachlorophenol (PCP) were compared. The results show that the two regeneration methods can eliminate contaminants from GAC and recover its adsorption properties to some extent. Comparing the DBD plasma with O3 regeneration, the adsorption rate and the capacity of the GAC samples after DBD plasma regeneration are greater than those after O3 regeneration. O3 regeneration decreases the specific surface area of GAC and increases the acidic surface oxygen groups on the surface of GAC, which causes a decrease in PCP on GAC uptake. With increasing regeneration cycles, the regeneration efficiencies of the two methods decrease, but the decrease in the regeneration efficiencies of GAC after O3 regeneration is very obvious compared with that after DBD plasma regeneration. Furthermore, the equilibrium data were fitted by the Freundlich and Langmuir models using the non-linear regression technique, and all the adsorption equilibrium isotherms fit the Langmuir model fairly well, which demonstrates that the DBD plasma and ozone regeneration processes do not appear to modify the adsorption process, but to shift the equilibrium towards lower adsorption concentrations. Analyses of the weight loss of GAC show that O3 regeneration has a lower weight loss than DBD plasma regeneration.

  8. Comparison Between Dielectric Barrier Discharge Plasma and Ozone Regenerations of Activated Carbon Exhausted with Pentachlorophenol

    In this study, two regeneration methods (dielectric barrier discharge (DBD) plasma and ozone (O3) regeneration) of saturated granular activated carbon (GAC) with pentachlorophenol (PCP) were compared. The results show that the two regeneration methods can eliminate contaminants from GAC and recover its adsorption properties to some extent. Comparing the DBD plasma with O3 regeneration, the adsorption rate and the capacity of the GAC samples after DBD plasma regeneration are greater than those after O3 regeneration. O3 regeneration decreases the specific surface area of GAC and increases the acidic surface oxygen groups on the surface of GAC, which causes a decrease in PCP on GAC uptake. With increasing regeneration cycles, the regeneration efficiencies of the two methods decrease, but the decrease in the regeneration efficiencies of GAC after O3 regeneration is very obvious compared with that after DBD plasma regeneration. Furthermore, the equilibrium data were fitted by the Freundlich and Langmuir models using the non-linear regression technique, and all the adsorption equilibrium isotherms fit the Langmuir model fairly well, which demonstrates that the DBD plasma and ozone regeneration processes do not appear to modify the adsorption process, but to shift the equilibrium towards lower adsorption concentrations. Analyses of the weight loss of GAC show that O3 regeneration has a lower weight loss than DBD plasma regeneration

  9. The transcription factor Sox11 promotes nerve regeneration through activation of the regeneration-associated gene Sprr1a

    Jing, Xiaotang; Wang, Ting; Huang, Shaohua; Glorioso, Joseph C.; Albers, Kathryn M.

    2011-01-01

    Factors that enhance the intrinsic growth potential of adult neurons are key players in the successful repair and regeneration of neurons following injury. Injury-induced activation of transcription factors has a central role in this process because they regulate expression of regeneration-associated genes. Sox11 is a developmentally expressed transcription factor that is significantly induced in adult neurons in response to injury. Its function in injured neurons is however undefined. Here, ...

  10. PERFORMANCE OF ACTIVATED SLUDGE-POWDERED ACTIVATED CARBON-WET AIR REGENERATION SYSTEMS

    The investigation summarized in the report was undertaken to evaluate the performance of powdered activated carbon (PAC) technology used in conjunction with wet air regeneration (WAR) at municipal wastewater treatment plants. Excessive ash concentrations accumulated in the mixed ...

  11. Aberrant innate immune activation following tissue injury impairs pancreatic regeneration.

    Alexandra E Folias

    Full Text Available Normal tissue architecture is disrupted following injury, as resident tissue cells become damaged and immune cells are recruited to the site of injury. While injury and inflammation are critical to tissue remodeling, the inability to resolve this response can lead to the destructive complications of chronic inflammation. In the pancreas, acinar cells of the exocrine compartment respond to injury by transiently adopting characteristics of progenitor cells present during embryonic development. This process of de-differentiation creates a window where a mature and stable cell gains flexibility and is potentially permissive to changes in cellular fate. How de-differentiation can turn an acinar cell into another cell type (such as a pancreatic β-cell, or a cell with cancerous potential (as in cases of deregulated Kras activity is of interest to both the regenerative medicine and cancer communities. While it is known that inflammation and acinar de-differentiation increase following pancreatic injury, it remains unclear which immune cells are involved in this process. We used a combination of genetically modified mice, immunological blockade and cellular characterization to identify the immune cells that impact pancreatic regeneration in an in vivo model of pancreatitis. We identified the innate inflammatory response of macrophages and neutrophils as regulators of pancreatic regeneration. Under normal conditions, mild innate inflammation prompts a transient de-differentiation of acinar cells that readily dissipates to allow normal regeneration. However, non-resolving inflammation developed when elevated pancreatic levels of neutrophils producing interferon-γ increased iNOS levels and the pro-inflammatory response of macrophages. Pancreatic injury improved following in vivo macrophage depletion, iNOS inhibition as well as suppression of iNOS levels in macrophages via interferon-γ blockade, supporting the impairment in regeneration and the

  12. STIMULATION OF RAPID REGENERATION BY A MAGNETIC FIELD IN PAULOWNIA NODE CULTURES

    Özge Çelik

    2008-11-01

    Full Text Available In this study, the aim was to determine the effect of magnetic fields on regeneration of Paulownia node cultures. Paulownia tomentosa node cultures were used to generate explants and these explants were passed through a 2.9- 4.6-mT magnetic flux density 1 and 9 times at 2.2 and 19.8 seconds, respectively. Chlorophyll quantities, total RNA concentrations of shoots and shoot formation rates from control and treated explants were determined. While the shoot formation rate was 61.9% in the control group, this rate was increased in magnetic field experiments and shoot formation was 82.5% in the explants that were exposed to a magnetic field for a 2.2 second period. However, the regeneration percentage of the explants exposed to a MF for a period of 19.8 s was 45%. Chlorophyll a, chlorophyll b and total chlorophyll contents of the 2.2 s group were increased in comparison to the control group. Total RNA concentrations of seedlings regenerated from treatment explants treated for 2.2 seconds significantly increased in comparison to the control (p<0.05. Our experiments show that the exposure duration to MFs is an important factor for plant tissue. MFs may be used in in vitro regeneration studies rapid and for a short time.

  13. Activation of the Canonical Wnt Signaling Pathway Induces Cementum Regeneration.

    Han, Pingping; Ivanovski, Saso; Crawford, Ross; Xiao, Yin

    2015-07-01

    Canonical Wnt signaling is important in tooth development but it is unclear whether it can induce cementogenesis and promote the regeneration of periodontal tissues lost because of disease. Therefore, the aim of this study is to investigate the influence of canonical Wnt signaling enhancers on human periodontal ligament cell (hPDLCs) cementogenic differentiation in vitro and cementum repair in a rat periodontal defect model. Canonical Wnt signaling was induced by (1) local injection of lithium chloride; (2) local injection of sclerostin antibody; and (3) local injection of a lentiviral construct overexpressing β-catenin. The results showed that the local activation of canonical Wnt signaling resulted in significant new cellular cementum deposition and the formation of well-organized periodontal ligament fibers, which was absent in the control group. In vitro experiments using hPDLCs showed that the Wnt signaling pathway activators significantly increased mineralization, alkaline phosphatase (ALP) activity, and gene and protein expression of the bone and cementum markers osteocalcin (OCN), osteopontin (OPN), cementum protein 1 (CEMP1), and cementum attachment protein (CAP). Our results show that the activation of the canonical Wnt signaling pathway can induce in vivo cementum regeneration and in vitro cementogenic differentiation of hPDLCs. PMID:25556853

  14. Optimization of the performance characteristics in an irreversible regeneration magnetic Brayton refrigeration cycle

    Wang, Hao; Wu, GuoXing

    2012-02-01

    A model of the irreversible regenerative Brayton refrigeration cycle working with paramagnetic materials is established, in which the regeneration problem in two constant-magnetic field processes and the irreversibility in two adiabatic processes are considered synthetically. Expressions for the COP, cooling rate, power input, the minimum ratio of the two magnetic fields, etc., are derived. It is found that the influence of the irreversibility and the regeneration on the main performance parameters of the magnetic Brayton refrigerator is remarkable. It is important that we have obtained several optimal criteria, which may provide some theoretical basis for the optimal design and operation of the Brayton refrigerator. The results obtained in the paper can provide some new theoretical information for the optimal design and performance improvement of real Brayton refrigerators.

  15. Activated carbon/Fe(3)O(4) nanoparticle composite: fabrication, methyl orange removal and regeneration by hydrogen peroxide.

    Do, Manh Huy; Phan, Ngoc Hoa; Nguyen, Thi Dung; Pham, Thi Thu Suong; Nguyen, Van Khoa; Vu, Thi Thuy Trang; Nguyen, Thi Kim Phuong

    2011-11-01

    In the water treatment field, activated carbons (ACs) have wide applications in adsorptions. However, the applications are limited by difficulties encountered in separation and regeneration processes. Here, activated carbon/Fe(3)O(4) nanoparticle composites, which combine the adsorption features of powdered activated carbon (PAC) with the magnetic and excellent catalytic properties of Fe(3)O(4) nanoparticles, were fabricated by a modified impregnation method using HNO(3) as the carbon modifying agent. The obtained composites were characterized by X-ray diffraction, scanning and transmission electron microscopy, nitrogen adsorption isotherms and vibrating sample magnetometer. Their performance for methyl orange (MO) removal by adsorption was evaluated. The regeneration of the composite and PAC-HNO(3) (powdered activated carbon modified by HNO(3)) adsorbed MO by hydrogen peroxide was investigated. The composites had a high specific surface area and porosity and a superparamagnetic property that shows they can be manipulated by an external magnetic field. Adsorption experiments showed that the MO sorption process on the composites followed pseudo-second order kinetic model and the adsorption isotherm date could be simulated with both the Freundlich and Langmuir models. The regeneration indicated that the presence of the Fe(3)O(4) nanoparticles is important for a achieving high regeneration efficiency by hydrogen peroxide. PMID:21840037

  16. Cyclic dermal BMP signaling regulates stem cell activation during hair regeneration

    Plikus, Maksim V; Mayer, Julie; de la Cruz, Damon; Baker, Ruth E.; Maini, Philip K.; Maxson, Robert; Chuong, Cheng-ming

    2008-01-01

    In the age of stem cell engineering, it is critical to understand how stem cell activity is regulated during regeneration. Hairs are mini-organs that undergo cyclic regeneration throughout adult life,1 and are an important model for organ regeneration. Hair stem cells located in the follicle bulge2 are regulated by the surrounding micro-environment, or niche3. The activation of such stem cells is cyclic, involving periodic β-catenin activity4–7. In adult mouse, regeneration occurs in waves in...

  17. Micromachined Active Magnetic Regenerator for Low Temperature Magnetic Coolers Project

    National Aeronautics and Space Administration — NASA's future science missions to investigate the structure and evolution of the universe require highly efficient, very low temperature coolers for low noise...

  18. Persulfate Oxidation Regeneration of Granular Activated Carbon: Reversible Impacts on Sorption Behavior

    Chemical oxidation regeneration of granular activated carbon (GAC) is a developing technology that can be carried out utilizing thermally-activated persulfate. During chemical regeneration of GAC, aggressive oxidative conditions lead to high acidity (pH < 2) and the accumulation ...

  19. STIMULATION OF RAPID REGENERATION BY A MAGNETIC FIELD IN PAULOWNIA NODE CULTURES

    Özge Çelik; Çimen Atak; Aitekin Rzakulieva

    2008-01-01

    In this study, the aim was to determine the effect of magnetic fields on regeneration of Paulownia node cultures. Paulownia tomentosa node cultures were used to generate explants and these explants were passed through a 2.9- 4.6-mT magnetic flux density 1 and 9 times at 2.2 and 19.8 seconds, respectively. Chlorophyll quantities, total RNA concentrations of shoots and shoot formation rates from control and treated explants were determined. While the shoot formation rate was 61.9% in the contro...

  20. A cost-effective and versatile technology for regenerating activated carbon

    McLaughlin, H. [Waste Min, Inc., Croton, MA (United States)

    1996-12-31

    Adsorption by activated carbon is a mainstream technology for the removal of soluble chemicals from waters and wastewaters, as well as for the removal of organics from vapor streams. Activated carbon basically acts like a sponge - accumulating the chemical species removed from the liquid or vapor stream. When the capacity of the carbon is reached, the spent carbon must be replaced or regenerated to restore its ability to adsorb. The current commercial regeneration options for spent carbon have significant shortcomings. Regeneration by steaming or low temperature heating removes low boiling organic compounds from vapor-phase carbon, but is not efficient removing less volatile compounds and does not regenerate liquid-phase activated carbons. High temperature thermal regeneration methods are expensive to build and operate, have high energy requirements, destroy the adsorbed compounds, and gradually destroy the carbon itself. An alternative technology that avoids the shortcomings of current methods is regeneration of spent activated carbon by extraction with organic solvents. The process uses an organic solvent to dissolve adsorbed material out of the internal pores of the activated carbon. Subsequently, the residual solvent is removed, typically by steaming, then the solvent is recovered and recycled. Cost-wise, solvent regeneration of activated carbon is substantially less expensive than thermal methods. The solvent regeneration technology works for virtually all adsorption applications where thermal regeneration is currently utilized. Capacity-wise, solvent regeneration restores 70% to 90% of the adsorption capacity of virgin activated carbon - while recovering the adsorbates intact and without deteriorating the activated carbon. 3 refs., 2 figs.

  1. Experimental and numerical results of a high frequency rotating active magnetic refrigerator

    Lozano, Jaime; Engelbrecht, Kurt; Bahl, Christian; Nielsen, Kaspar Kirstein; Barbosa Jr., J.R.; Prata, A. T.; Pryds, Nini

    2012-01-01

    Experimental results for a recently developed prototype magnetic refrigeration device at The Technical University of Denmark (DTU) were obtained and compared with numerical simulation results. A continuously rotating active magnetic regenerator (AMR) using 2.8 kg packed sphere regenerators of commercial grade gadolinium (Gd) was employed. With operating frequencies up to 10 Hz and volumetric flow rates up to 600 L/h, the prototype has shown high performance and the results are consistent with...

  2. Experimental and numerical results of a high frequency rotating active magnetic refrigerator

    Lozano, Jaime; Engelbrecht, Kurt; Bahl, Christian;

    2012-01-01

    Experimental results for a recently developed prototype magnetic refrigeration device at The Technical University of Denmark (DTU) were obtained and compared with numerical simulation results. A continuously rotating active magnetic regenerator (AMR) using 2.8 kg packed sphere regenerators of...... function of cycle frequency was determined. It was found that thermal losses increase as the frequency increases. Therefore, a detailed study of these parasitic losses was carried out experimentally and numerically....

  3. The utility of magnetic resonance imaging in cardiac tissue regeneration trials.

    Fuster, Valentin; Sanz, Javier; Viles-Gonzalez, Juan F; Rajagopalan, Sanjay

    2006-03-01

    The past decade has seen the emergence of paradigm shifts in concepts involving cardiovascular tissue regeneration, including the idea that adult stem cells originate in hematopoietic or bone marrow cells, the belief that even adult organs, such as the heart and nervous system, are capable of post-mitotic regeneration, and the concept of inherent plasticity in cells that have undergone limited lineage differentiation. There has consequently been a flurry of proposed regenerative strategies, and safety and limited efficacy data from both animal and limited human trials have been presented. The drive to push these advances from the bench to the bedside has created a unique environment where the therapeutic agents, delivery approaches, and methods of measuring efficacy (often imaging technology) are evolving practically in parallel. The encouraging results of recent cell-therapy trials should therefore be assessed cautiously and in consonance with an understanding of the advantages and limitations of delivery strategies and end points. Arguably, the use of imaging technologies to evaluate surrogate end points might help overcome the difficulty posed by large sample sizes required for hard end point trials in cardiovascular therapeutics. Cardiac magnetic resonance imaging is one of the most sensitive techniques available to assess spatial and temporal changes following local or systemic therapies, and the availability of a bevy of complementary techniques enables interrogation of physiology, morphology, and metabolism in one setting. We contend that cardiac magnetic resonance imaging is ideally suited to assess response to myocardial regeneration therapy and can be exploited to yield valuable insights into the mechanism of action of myocardial regeneration therapies. PMID:16501625

  4. Active Magnetic Bearings – Magnetic Forces

    Kjølhede, Klaus

    2006-01-01

    the work is the characterization of magnetic forces by using two experimental different experimental approaches. Such approaches are investigated and described in details. A special test rig is designed where the 4 poles - AMB is able to generate forces up to 1900 N. The high precision......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...... characterization 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...

  5. Active Magnetic Bearings – Magnetic Forces

    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...... the work is the characterization of magnetic forces by using two experimental different experimental approaches. Such approaches are investigated and described in details. A special test rig is designed where the 4 poles - AMB is able to generate forces up to 1900 N. The high precision...... characterization 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...

  6. Design and performance study of the active magnetic refrigerator for room-temperature application

    Zheng, Z.G.; Yu, H.Y.; Zhong, X.C.; Zeng, D.C.; Liu, Z.W. [School of Materials Science and Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640 (China)

    2009-01-15

    A room-temperature magnetic refrigerator, consisting of permanent magnet, active magnetic refrigeration (AMR) cycle bed, pumps, hydraulic circuit, active magnetic double regenerator cycle (AM2RC) and control subsystems, has been designed. The magnetic field is supplied by NdFeB permanent magnets. The AMR bed made by stainless steel 304 encloses gadolinium particles as the magnetic working substance. Each part of the refrigerator is controlled by the programmable controller. The different standard heat exchangers are employed to expel heat. The cycle performance of this self-designed facility is analyzed using Langevin theory. The results provide useful data for future design and development of room-temperature magnetic refrigeration. (author)

  7. A new method of regenerating activated carbon by thermal desorption with liquid water under subcritical conditions

    Salvador, F.; Sanchez Jimenez, C. [Universidad de Salamanca, Salamanca (Spain). Dept. de Quimica Fisica

    1996-06-01

    This paper discusses a new procedure for regenerating activated carbon based on thermal desorption with liquid water under subcritical conditions (300{degree}C and 120 atm). The method was assayed with three types of activated carbons exhausted with phenols (phenol and 4-nitrophenol), textile dyes (sirius red C.I.:29080 and orange II C.I.:15510) and pesticides (carbonfuran and atrazine). In all cases, total recovery of the adsorption capacity was achieved, even after seven regenerations. The mechanism and factors involved in regeneration were investigated using the TPD technique in liquid phase. The differences and advantages of this procedure as compared with others, such as thermal regeneration or regeneration with supercritical CO{sub 2} are discussed. 20 refs., 5 figs., 1 tab.

  8. Impulse magnetic stimulation facilitates synaptic regeneration in rats following sciatic nerve injury

    Sergey A. Zhivolupov; Miroslav M. Odinak; Nariman A. Rashidov; Ludmila S. Onischenko; Igor N. Samartsev; Anton A. Jurin

    2012-01-01

    The current studies describing magnetic stimulation for treatment of nervous system diseases mainly focus on transcranial magnetic stimulation and rarely focus on spinal cord magnetic stimula-tion. Spinal cord magnetic stimulation has been confirmed to promote neural plasticity after injuries of spinal cord, brain and peripheral nerve. To evaluate the effects of impulse magnetic stimulation of the spinal cord on peripheral nerve regneration, we compressed a 3 mm segment located in the middle third of the hip using a sterilized artery forceps to induce ischemia. Then, all animals un-derwent impulse magnetic stimulation of the lumbar portion of spinal crod and spinal nerve roots daily for 1 month. Electron microscopy results showed that in and below the injuryed segment, the inflammation and demyelination of neural tissue were alleviated, apoptotic cells were reduced, and injured Schwann cells and myelin fibers were repaired. These findings suggest that high-frequency impulse magnetic stimulation of spinal cord and corresponding spinal nerve roots promotes synaptic regeneration following sciatic nerve injury.

  9. Stellar magnetic activity

    The stellar emission in the chromospheric Ca II H+K lines is compared with the coronal soft X-ray emission, measuring the effects of non-radiative heating in the outer atmosphere at temperatures differing two orders of magnitude. The comparison of stellar flux densities in Ca II H+K and X-rays is extended to fluxes from the transition-region and the high-temperature chromosphere. The stellar magnetic field is probably generated in the differentially rotating convective envelope. The relation between rotation rate and the stellar level of activity measured in chromospheric, transition-region, and coronal radiative diagnostics is discovered. X-ray observations of the binary λ Andromedae are discussed. The departure of M-type dwarfs from the main relations, and the implications for the structure of the chromospheres of these stars are discussed. Variations of the average surface flux densities of the Sun during the 11-year activity cycle agree with flux-flux relations derived for other cool stars, suggesting that the interpretation of the stellar relations may be furthered by studying the solar analogue in more detail. (Auth.)

  10. Regeneration of spent powdered activated carbon saturated with inorganic ions by cavitation united with ion exchange method.

    Li, Gang; Gao, Hong; Li, Yansheng; Yang, Huixin

    2011-06-01

    Using ion exchange resin as transfer media, regenerate powdered activated carbon (PAC) adsorbed inorganic ions by cavitation to enhance the transfer; we studied how the regeneration time and the mass ratio of resin and PAC influence the regeneration rate respectively through re-adsorption. The result showed that the effective regeneration of PAC saturated with inorganic ions was above 90% using ion exchange resin as media and transfer carrier, the quantity of PAC did not reduced but activated in the process. PMID:25084579

  11. Effects of microwave heating on porous structure of regenerated powdered activated carbon used in xylose.

    Li, Wei; Wang, Xinying; Peng, Jinhui

    2014-01-01

    The regeneration of spent powdered activated carbons used in xylose decolourization by microwave heating was investigated. Effects of microwave power and microwave heating time on the adsorption capacity of regenerated activated carbons were evaluated. The optimum conditions obtained are as follows: microwave power 800W; microwave heating time 30min. Regenerated activated carbon in this work has high adsorption capacities for the amount of methylene blue of 16 cm3/0.1 g and the iodine number of 1000.06mg/g. The specific surface areas of fresh commercial activated carbon, spent carbon and regenerated activated carbon were calculated according to the Brunauer, Emmett and Teller method, and the pore-size distributions of these carbons were characterized by non-local density functional theory (NLDFT). The results show that the specific surface area and the total pore volume of regenerated activated carbon are 1064 m2/g and 1.181 mL/g, respectively, indicating the feasibility of regeneration of spent powdered activated carbon used in xylose decolourization by microwave heating. The results of surface fractal dimensions also confirm the results of isotherms and NLDFT. PMID:24645431

  12. A nonventing cooling system for space environment extravehicular activity, using radiation and regenerable thermal storage

    Bayes, Stephen A.; Trevino, Luis A.; Dinsmore, Craig E.

    1988-01-01

    This paper outlines the selection, design, and testing of a prototype nonventing regenerable astronaut cooling system for extravehicular activity space suit applications, for mission durations of four hours or greater. The selected system consists of the following key elements: a radiator assembly which serves as the exterior shell of the portable life support subsystem backpack; a layer of phase change thermal storage material, n-hexadecane paraffin, which acts as a regenerable thermal capacitor; a thermoelectric heat pump; and an automatic temperature control system. The capability for regeneration of thermal storage capacity with and without the aid of electric power is provided.

  13. Regulation of skeletal muscle regeneration by CCR2-activating chemokines is directly related to macrophage recruitment

    Martinez, Carlo O.; McHale, Matthew J.; Wells, Jason T.; OCHOA, OSCAR; Joel E. Michalek; McManus, Linda M.; Shireman, Paula K.

    2010-01-01

    Muscle regeneration requires CC chemokine receptor 2 (CCR2) expression on bone marrow-derived cells; macrophages are a prominent CCR2-expressing cell in this process. CCR2−/− mice have severe impairments in angiogenesis, macrophage recruitment, and skeletal muscle regeneration following cardiotoxin (CTX)-induced injury. However, multiple chemokines activate CCR2, including monocyte chemotactic proteins (MCP)-1, -3, and -5. We hypothesized that MCP-1 is the chemokine ligand that mediates the i...

  14. Repetitive magnetic stimulation affects the microenvironment of nerve regeneration and evoked potentials after spinal cord injury

    Jiang, Jin-lan; Guo, Xu-dong; Zhang, Shu-quan; Wang, Xin-gang; Wu, Shi-feng

    2016-01-01

    Repetitive magnetic stimulation has been shown to alter local blood flow of the brain, excite the corticospinal tract and muscle, and induce motor function recovery. We established a rat model of acute spinal cord injury using the modified Allen's method. After 4 hours of injury, rat models received repetitive magnetic stimulation, with a stimulus intensity of 35% maximum output intensity, 5-Hz frequency, 5 seconds for each sequence, and an interval of 2 minutes. This was repeated for a total of 10 sequences, once a day, 5 days in a week, for 2 consecutive weeks. After repetitive magnetic stimulation, the number of apoptotic cells decreased, matrix metalloproteinase 9/2 gene and protein expression decreased, nestin expression increased, somatosensory and motor-evoked potentials recovered, and motor function recovered in the injured spinal cord. These findings confirm that repetitive magnetic stimulation of the spinal cord improved the microenvironment of neural regeneration, reduced neuronal apoptosis, and induced neuroprotective and repair effects on the injured spinal cord. PMID:27335567

  15. An experimental study of passive regenerator geometries

    Engelbrecht, Kurt; Nielsen, Kaspar Kirstein; Pryds, Nini

    2011-01-01

    Active magnetic regenerative (AMR) systems are being investigated because they represent a potentially attractive alternative to vapor compression technology. The performance of these systems is dependent on the heat transfer and pressure drop performance of the regenerator geometry. Therefore th...

  16. Regulation of skeletal muscle regeneration by CCR2-activating chemokines is directly related to macrophage recruitment.

    Martinez, Carlo O; McHale, Matthew J; Wells, Jason T; Ochoa, Oscar; Michalek, Joel E; McManus, Linda M; Shireman, Paula K

    2010-09-01

    Muscle regeneration requires CC chemokine receptor 2 (CCR2) expression on bone marrow-derived cells; macrophages are a prominent CCR2-expressing cell in this process. CCR2-/- mice have severe impairments in angiogenesis, macrophage recruitment, and skeletal muscle regeneration following cardiotoxin (CTX)-induced injury. However, multiple chemokines activate CCR2, including monocyte chemotactic proteins (MCP)-1, -3, and -5. We hypothesized that MCP-1 is the chemokine ligand that mediates the impairments present in CCR2-/- mice. We examined muscle regeneration, capillary density, and cellular recruitment in MCP-1-/- and CCR2-/- mice following injury. Muscle regeneration and adipocyte accumulation, but not capillary density, were significantly impaired in MCP-1-/- compared with wild-type (WT) mice; however, muscle regeneration and adipocyte accumulation impairments were not as severe as observed in CCR2-/- mice. Although tissue levels of MCP-5 were elevated in MCP-1-/- mice compared with WT, the administration of MCP-5 neutralizing antibody did not alter muscle regeneration in MCP-1-/- mice. While neutrophil accumulation after injury was similar in all three mouse strains, macrophage recruitment was highest in WT mice, intermediate in MCP-1-/- mice, and severely impaired in CCR2-/- mice. In conclusion, while the absence of MCP-1 resulted in impaired macrophage recruitment and muscle regeneration, MCP-1-/- mice exhibit an intermediate phenotype compared with CCR2-/- mice. Intermediate macrophage recruitment in MCP-1-/- mice was associated with similar capillary density to WT, suggesting that fewer macrophages may be needed to restore angiogenesis vs. muscle regeneration. Finally, other chemokines, in addition to MCP-1 and MCP-5, may activate CCR2-dependent regenerative processes resulting in an intermediate phenotype in MCP-1-/- mice. PMID:20631294

  17. Hyaluronic acid production and hyaluronidase activity in the newt iris during lens regeneration

    The process of lens regeneration in newts involves the dedifferentiation of pigmented iris epithelial cells and their subsequent conversion into lens fibers. In vivo this cell-type conversion is restricted to the dorsal region of the iris. We have examined the patterns of hyaluronate accumulation and endogenous hyaluronidase activity in the newt iris during the course of lens regeneration in vivo. Accumulation of newly synthesized hyaluronate was estimated from the uptake of [3H]glucosamine into cetylpyridinium chloride-precipitable material that was sensitive to Streptomyces hyaluronidase. Endogenous hyaluronidase activity was determined from the quantity of reducing N-acetylhexosamine released upon incubation of iris tissue extract with exogenous hyaluronate substrate. We found that incorporation of label into hyaluronate was consistently higher in the regeneration-activated irises of lentectomized eyes than in control irises from sham-operated eyes. Hyaluronate labeling was higher in the dorsal (lens-forming) region of the iris than in ventral (non-lens-forming) iris tissue during the regeneration process. Label accumulation into hyaluronate was maximum between 10 and 15 days after lentectomy, the period of most pronounced dedifferentiation in the dorsal iris epithelium. Both normal and regenerating irises demonstrated a high level of endogenous hyaluronidase activity with a pH optimum of 3.5-4.0. Hyaluronidase activity was 1.7 to 2 times higher in dorsal iris tissue than in ventral irises both prior to lentectomy and throughout the regeneration process. We suggest that enhanced hyaluronate accumulation may facilitate the dedifferentiation of iris epithelial cells in the dorsal iris and prevent precocious withdrawal from the cell cycle. The high level of hyaluronidase activity in the dorsal iris may promote the turnover and remodeling of extracellular matrix components required for cell-type conversion

  18. Hyaluronic acid production and hyaluronidase activity in the newt iris during lens regeneration

    Kulyk, W.M.; Zalik, S.E.; Dimitrov, E.

    1987-09-01

    The process of lens regeneration in newts involves the dedifferentiation of pigmented iris epithelial cells and their subsequent conversion into lens fibers. In vivo this cell-type conversion is restricted to the dorsal region of the iris. We have examined the patterns of hyaluronate accumulation and endogenous hyaluronidase activity in the newt iris during the course of lens regeneration in vivo. Accumulation of newly synthesized hyaluronate was estimated from the uptake of (/sup 3/H)glucosamine into cetylpyridinium chloride-precipitable material that was sensitive to Streptomyces hyaluronidase. Endogenous hyaluronidase activity was determined from the quantity of reducing N-acetylhexosamine released upon incubation of iris tissue extract with exogenous hyaluronate substrate. We found that incorporation of label into hyaluronate was consistently higher in the regeneration-activated irises of lentectomized eyes than in control irises from sham-operated eyes. Hyaluronate labeling was higher in the dorsal (lens-forming) region of the iris than in ventral (non-lens-forming) iris tissue during the regeneration process. Label accumulation into hyaluronate was maximum between 10 and 15 days after lentectomy, the period of most pronounced dedifferentiation in the dorsal iris epithelium. Both normal and regenerating irises demonstrated a high level of endogenous hyaluronidase activity with a pH optimum of 3.5-4.0. Hyaluronidase activity was 1.7 to 2 times higher in dorsal iris tissue than in ventral irises both prior to lentectomy and throughout the regeneration process. We suggest that enhanced hyaluronate accumulation may facilitate the dedifferentiation of iris epithelial cells in the dorsal iris and prevent precocious withdrawal from the cell cycle. The high level of hyaluronidase activity in the dorsal iris may promote the turnover and remodeling of extracellular matrix components required for cell-type conversion.

  19. Thermal regeneration of activated carbons saturated with ortho- and meta-chlorophenols

    Maroto-Valer, M. Mercedes [School of Chemical, Environmental and Mining Engineering, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Dranca, Ion; Clifford, David [The Energy Institute of the Penn State University, University Park, PA 16802 (United States); Lupascu, Tudor; Nastas, Raisa [Institute of Chemistry of the Academy of Sciences, Chisinau MD 2028 (Moldova, Republic of); Leon y Leon, Carlos A. [Quantachrome Instruments, Boynton Beach, FL 33426 (United States)

    2006-05-15

    Activated carbons (ACs) made from peach and plum stones were oxidized and impregnated with salts of Cu(II), Fe(III), Ni(II) and Cr(III). The chemically modified ACs, along with a commercial AC (S208c), were saturated with ortho- (OCP) and meta-chlorophenol (MCP) to investigate the potential for thermally regenerating the spent ACs. The thermal regeneration process was monitored by thermal analysis (TGA/DSC), gas chromatography and mass spectrometry (GC/MS). Thermal desorption profiles showed that in most cases weight losses occur in two steps (weak physisorption at circa 220{sup o}C and strong chemisorption at circa 620{sup o}C). Intermediate steps at circa 400{sup o}C appeared in samples whose chemical treatments successfully weakened the interactions between strongly chemisorbed chlorophenol (CP) molecules and AC surfaces. The type and quantity of products of OCP and MCP desorption during the thermal regeneration of a spent AC depend on the chemical modification given to the AC prior to its use as CP adsorbent. Besides the original chlorophenols, thermal regeneration products can include chlorobenzene, dichloro-dibenzofuran, phenol, aliphatic and aromatic hydrocarbons, water, chlorides, carbon oxides, hydrogen, and char deposits. Mechanisms for the formation of these compounds are discussed. The char deposits built during this study did not appear to diminish the surface area or porosity of the chemically modified ACs following their thermal regeneration. (author)

  20. Regeneration of acid orange 7-exhausted granular activated carbons with microwave irradiation.

    Quan, Xie; Liu, Xitao; Bo, Longli; Chen, Shuo; Zhao, Yazhi; Cui, Xinyi

    2004-12-01

    An investigation was performed for the regeneration of three granular activated carbons (GACs) exhausted with acid orange 7 (AO7). The three GACs were made from different materials, i.e. coconut shells, almond nucleus and coal. The AO7 adsorption process was carried out in a continuous-flow adsorption column. After adsorption, the AO7-saturated GAC was dried at 120 degrees C, then regenerated in a quartz reactor by 2450 MHz microwave (MW) irradiation at 850 W for 5 min. The efficacy of this procedure was analyzed by determining the rates and amounts of AO7 adsorbed in successive adsorption-MW regeneration cycles. Effects of this regeneration on the structural properties, surface chemistry and the AO7 adsorption capacities of GAC samples were examined. It was found that after several adsorption-MW regeneration cycles, the adsorption rates and capacities of GACs could maintain relatively high levels, even higher than those of virgin GACs, as indicated by AO7 breakthrough curves and adsorption isotherms. The improvement of GAC adsorption properties resulted from the modification of pore size distribution and surface chemistry by MW irradiation. PMID:15556223

  1. Impact of Cylinder Deactivation on Active Diesel Particulate Filter Regeneration at Highway Cruise Conditions

    Lu, Xueting; Ding, Chuan; Ramesh, Aswin K.; Shaver, Gregory M.; Holloway, Eric; McCarthy, James; Ruth, Michael; Koeberlein, Edward; Nielsen, Douglas

    2015-01-01

    Heavy-duty over-the-road trucks require periodic active diesel particulate filter regeneration to clean the filter of stored particulate matter. These events require sustained temperatures between 500 and 600°C to complete the regeneration process. Engine operation during typical 65 mile/h highway cruise conditions (1200 rpm/7.6 bar) results in temperatures of approximately 350°C, and can reach approximately 420°C with late fuel injection. This necessitates hydrocarbon fueling of a diesel oxi...

  2. Post-combustion CO2 capture with a commercial activated carbon: Comparison of different regeneration strategies

    González Plaza, Marta; García López, Susana; Rubiera González, Fernando; Pis Martínez, José Juan; Pevida García, Covadonga

    2010-01-01

    A commercial activated carbon supplied by Norit, R2030CO2, was evaluated as CO2 adsorbent under conditions relevant to post-combustion CO2 capture (ambient pressure and diluted CO2). It has been demonstrated that this carbon possesses sufficient CO2/N2 selectivity in order to efficiently separate a binary mixture composed of 17% CO2 in N2. Moreover, this carbon was easily completely regenerated and it did not show capacity decay after 10 consecutive cycles. Three different regeneration strate...

  3. Experimental and numerical results of a high frequency rotating active magnetic refrigerator

    Lozano, Jaime; Engelbrecht, Kurt; Bahl, Christian R.H.;

    2014-01-01

    Experimental results for a recently developed prototype magnetic refrigeration device at the Technical University of Denmark (DTU) were obtained and compared with numerical simulation results. A continuously rotating active magnetic regenerator (AMR) using 2.8 kg packed sphere regenerators of...... implemented in a one-dimensional numerical AMR model that includes also the parasitic losses from the prototype. The temperature span for a thermal load of 200 W as a function of frequency was measured and modelled. Moreover, the temperature span dependence on the cooling capacity as a function of cycle...

  4. Cyclic dermal BMP signalling regulates stem cell activation during hair regeneration.

    Plikus, Maksim V; Mayer, Julie Ann; de la Cruz, Damon; Baker, Ruth E; Maini, Philip K; Maxson, Robert; Chuong, Cheng-Ming

    2008-01-17

    In the age of stem cell engineering it is critical to understand how stem cell activity is regulated during regeneration. Hairs are mini-organs that undergo cyclic regeneration throughout adult life, and are an important model for organ regeneration. Hair stem cells located in the follicle bulge are regulated by the surrounding microenvironment, or niche. The activation of such stem cells is cyclic, involving periodic beta-catenin activity. In the adult mouse, regeneration occurs in waves in a follicle population, implying coordination among adjacent follicles and the extrafollicular environment. Here we show that unexpected periodic expression of bone morphogenetic protein 2 (Bmp2) and Bmp4 in the dermis regulates this process. This BMP cycle is out of phase with the WNT/beta-catenin cycle, thus dividing the conventional telogen into new functional phases: one refractory and the other competent for hair regeneration, characterized by high and low BMP signalling, respectively. Overexpression of noggin, a BMP antagonist, in mouse skin resulted in a markedly shortened refractory phase and faster propagation of the regenerative wave. Transplantation of skin from this mutant onto a wild-type host showed that follicles in donor and host can affect their cycling behaviours mutually, with the outcome depending on the equilibrium of BMP activity in the dermis. Administration of BMP4 protein caused the competent region to become refractory. These results show that BMPs may be the long-sought 'chalone' inhibitors of hair growth postulated by classical experiments. Taken together, results presented in this study provide an example of hierarchical regulation of local organ stem cell homeostasis by the inter-organ macroenvironment. The expression of Bmp2 in subcutaneous adipocytes indicates physiological integration between these two thermo-regulatory organs. Our findings have practical importance for studies using mouse skin as a model for carcinogenesis, intra-cutaneous drug

  5. The Effects of Weak Combined Magnetic Field on Cell Wall Regeneration and Frequency of Plant Protoplasts Fusion

    Nedukha, Olena

    The major purpose of these experiments was to investigate plant protoplast fusion frequency and regeneration of a cell wall by protoplasts at weak combined magnetic field (CMF) with the frequency resonance to the cyclotron frequency of Mg2+, Ca2+ and K+ ions. The protoplasts were isolated from Nicotiana lumbaginifolia and N. silvestris leaf mesophyll and from callus tissues (Nicotiana tabacum and Glycine max). The special extra apparatus with ferromagnetic shield was used for estimate of CMF with the frequency resonance to the cyclotron frequency of Mg2+, Ca2+ and K+ ions. The fusion of protoplasts is realized by using of parent protoplasts isolated from one plant species, as well as from various plant species. Control samples were situated near the apparatus with CMF. The laser confocal microscopy was used for study of cell wall regeneration by single and fused protoplasts. The cytochemical methods with DAPI and calcofluor dye were also applied as the detectors for protoplast fusion and regeneration of cell wall. We have been established that CMF with frequency adjusted to the cyclotron frequency Mg2+ ions have shown the most positive influence on regeneration of cell wall by protoplasts. CMF adjusted to the cyclotron frequency of K+ ions very weakly affected on the frequency of protoplast fusion. Largest frequency of protoplasts fusion is noted in the CMF adjusted to the cyclotron frequency of Ca2+ in comparison with the control samples.

  6. Differentially activated macrophages orchestrate myogenic precursor cell fate during human skeletal muscle regeneration

    Saclier, Marielle; Yacoub-Youssef, Houda; Mackey, Abigail;

    2013-01-01

    Macrophages (MPs) exert either beneficial or deleterious effects on tissue repair, depending on their activation/polarization state. They are crucial for adult skeletal muscle repair, notably by acting on myogenic precursor cells. However, these interactions have not been fully characterized. Here......, we explored both in vitro and in vivo, in human, the interactions of differentially activated MPs with myogenic precursor cells (MPCs) during adult myogenesis and skeletal muscle regeneration. We showed in vitro that through the differential secretion of cytokines and growth factors, proinflammatory...... anti-inflammatory markers. These data demonstrate for the first time in human that MPs sequentially orchestrate adult myogenesis during regeneration of damaged skeletal muscle. These results support the emerging concept that inflammation, through MP activation, controls stem cell fate and coordinates...

  7. Optical Search for QED vacuum magnetic birefringence, Axions and photon Regeneration

    Srnka, A; Pugnat, P; Hryczuk, A; Slunecka, M; Jary, V; Finger, M; Finger, M; Kral, M

    2007-01-01

    Since its prediction in 1936 by Euler, Heisenberg and Weisskopf in the earlier development of the Quantum Electrodynamic (QED) theory, the Vacuum Magnetic Birefringence (VMB) is still a challenge for optical metrology techniques. According to QED, the vacuum behaves as an optically active medium in the presence of an external magnetic field. It can be experimentally probed with a linearly polarized laser beam. After propagating through the vacuum submitted to a transverse magnetic field, the polarization of the laser beam will change to elliptical and the parameters of the polarization are directly related to fundamental constants such as the fine structure constant and the electron Compton wavelength. Contributions to the VMB could also arise from the existence of light scalar or pseudo-scalar particles like axions that couple to two photons and this would manifest itself as a sizeable deviation from the initial QED prediction. On one side, the interest in axion search, providing an answer to the strong-CP p...

  8. Optimization of active magnetic regenerative refrigeration systems using Design of Experiments

    Roudaut, Julien; Bouchekara, Houssem; Kedous-Lebouc, Afef; Coulomb, Jean-Louis

    2009-01-01

    International audience This paper attends to demonstrate the usefulness of Design of Experiments (DOE) method in magnetic refrigeration (MR) understanding and optimization. A numerical DOE is applied to a simple 1D finite difference model describing an Active Magnetic Regenerative Refrigeration (AMRR) system. The heat transfer fluid is water, the regenerator consists of stacked gadolinium plates and the model is based on the assumption of an equivalent single plate. A two-level 27-3 fracti...

  9. Biomimetic three-dimensional nanocrystalline hydroxyapatite and magnetically synthesized single-walled carbon nanotube chitosan nanocomposite for bone regeneration

    Im O

    2012-04-01

    Full Text Available Owen Im1, Jian Li2, Mian Wang2, Lijie Grace Zhang2,3, Michael Keidar2,31Department of Biomedical Engineering, Duke University, Durham, NC; 2Department of Mechanical and Aerospace Engineering, 3Institute for Biomedical Engineering and Institute for Nanotechnology, The George Washington University, Washington, DC, USABackground: Many shortcomings exist in the traditional methods of treating bone defects, such as donor tissue shortages for autografts and disease transmission for allografts. The objective of this study was to design a novel three-dimensional nanostructured bone substitute based on magnetically synthesized single-walled carbon nanotubes (SWCNT, biomimetic hydrothermally treated nanocrystalline hydroxyapatite, and a biocompatible hydrogel (chitosan. Both nanocrystalline hydroxyapatite and SWCNT have a biomimetic nanostructure, excellent osteoconductivity, and high potential to improve the load-bearing capacity of hydrogels.Methods: Specifically, three-dimensional porous chitosan scaffolds with different concentrations of nanocrystalline hydroxyapatite and SWCNT were created to support the growth of human osteoblasts (bone-forming cells using a lyophilization procedure. Two types of SWCNT were synthesized in an arc discharge with a magnetic field (B-SWCNT and without a magnetic field (N-SWCNT for improving bone regeneration.Results: Nanocomposites containing magnetically synthesized B-SWCNT had superior cytocompatibility properties when compared with nonmagnetically synthesized N-SWCNT. B-SWCNT have much smaller diameters and are twice as long as their nonmagnetically prepared counterparts, indicating that the dimensions of carbon nanotubes can have a substantial effect on osteoblast attachment.Conclusion: This study demonstrated that a chitosan nanocomposite with both B-SWCNT and 20% nanocrystalline hydroxyapatite could achieve a higher osteoblast density when compared with the other experimental groups, thus making this nanocomposite

  10. Rac1 selective activation improves retina ganglion cell survival and regeneration.

    Erika Lorenzetto

    Full Text Available In adult mammals, after optic nerve injury, retinal ganglion cells (RGCs do not regenerate their axons and most of them die by apoptosis within a few days. Recently, several strategies that activate neuronal intracellular pathways were proposed to prevent such degenerative processes. The rho-related small GTPase Rac1 is part of a complex, still not fully understood, intracellular signaling network, mediating in neurons many effects, including axon growth and cell survival. However, its role in neuronal survival and regeneration in vivo has not yet been properly investigated. To address this point we intravitreally injected selective cell-penetrating Rac1 mutants after optic nerve crush and studied the effect on RGC survival and axonal regeneration. We injected two well-characterized L61 constitutively active Tat-Rac1 fusion protein mutants, in which a second F37A or Y40C mutation confers selectivity in downstream signaling pathways. Results showed that, 15 days after crush, both mutants were able to improve survival and to prevent dendrite degeneration, while the one harboring the F37A mutation also improved axonal regeneration. The treatment with F37A mutant for one month did not improve the axonal elongation respect to 15 days. Furthermore, we found an increase of Pak1 T212 phosphorylation and ERK1/2 expression in RGCs after F37A treatment, whereas ERK1/2 was more activated in glial cells after Y40C administration. Our data suggest that the selective activation of distinct Rac1-dependent pathways could represent a therapeutic strategy to counteract neuronal degenerative processes in the retina.

  11. The physico-chemical properties and biostimulative activities of humic substances regenerated from lignite

    David, Jan; Šmejkalová, Daniela; Hudecová, Šárka; Zmeškal, Oldřich; von Wandruszka, Ray; Gregor, Tomáš; Kučerík, Jiří

    2014-01-01

    The positive effect of humic acids on the growth of plant roots is well known, however, the mechanisms and role of their physical structure in these processes have not been fully explained yet. In this work, South-Moravian lignite was oxidized by means of nitric acid and hydrogen peroxide to produce a set of regenerated humic acids. The elemental composition, solid state stability and solution characteristics were determined and correlated in vitro with their biological activity. A modified h...

  12. Progenitor cells in liver regeneration: molecular responses controlling their activation and expansion

    Santoni-Rugiu, Eric; Jelnes, Peter; Thorgeirsson, Snorri S;

    2005-01-01

    biliary cells to restore liver homeostasis. In recent years, hepatic progenitor cells have been the subject of increasing interest due to their therapeutic potential in numerous liver diseases as alternative or supportive/complementary tools to liver transplantation. While the first investigations on......Although normally quiescent, the adult mammalian liver possesses a great capacity to regenerate after different types of injuries in order to restore the lost liver mass and ensure maintenance of the multiple liver functions. Major players in the regeneration process are mature residual cells......, including hepatocytes, cholangiocytes and stromal cells. However, if the regenerative capacity of mature cells is impaired by liver-damaging agents, hepatic progenitor cells are activated and expand into the liver parenchyma. Upon transit amplification, the progenitor cells may generate new hepatocytes and...

  13. Adsorption of nitrate from aqueous solution by magnetic amine-crosslinked biopolymer based corn stalk and its chemical regeneration property.

    Song, Wen; Gao, Baoyu; Xu, Xing; Wang, Fang; Xue, Nan; Sun, Shenglei; Song, Wuchang; Jia, Ruibao

    2016-03-01

    A novel adsorbent of magnetic amine-crosslinked biopolymer based corn stalk (MAB-CS) was synthesized and used for nitrate removal from aqueous solution. The characters and adsorption mechanisms of this bio-adsorbent were determined by using VSM, TGA, XRD, SEM, TEM, FT-IR and XPS, respectively. The results revealed that the saturated magnetization of MAB-CS reached 6.25 emu/g. Meanwhile, the studies of various factors indicated that this novel magnetic bio-adsorbent performed well over a considerable wide pH range of 6.0 ∼ 9.0, and the presence of PO4(3-) and SO4(2-) would markedly decrease the nitrate removal efficiency. Furthermore, the nitrate adsorption by MAB-CS perfectly fitted the Langmuir isotherm model (R(2)=0.997-0.999) and pseudo second order kinetic model (R(2)=0.953-0.995). The calculated nitrate adsorption capacity of MAB-CS was 102.04 mg/g at 318 K by Langmuir model, and thermodynamic study showed that nitrate adsorption is an spontaneous endothermic process. The regeneration experiments indicated its merit of regeneration and stability with the recovery efficient of 118 ∼ 147%. By integrating the experimental results, it was found that the removal of nitrate was mainly via electrostatic attraction and ion exchange. And this novel bio-adsorbent prepared in this work could achieve effective removal of nitrate and rapid separation from effluents simultaneously. PMID:26561752

  14. Diffusion in active magnetic colloids

    Properties of active colloids of circle swimmers are reviewed. As a particular example of active magnetic colloids the magnetotactic bacteria under the action of a rotating magnetic field is considered. The relation for a diffusion coefficient due to the random switching of the direction of rotation of their rotary motors is derived on the basis of the master equation. The obtained relation is confirmed by the direct numerical simulation of random trajectory of a magnetotactic bacterium under the action of the Poisson type internal noise due to the random switching of rotary motors. The results obtained are in qualitative and quantitative agreement with the available experimental results and allow one to determine the characteristic time between the switching events of a rotary motor of the bacterium. - Highlights: • Magnetotactic bacteria in a rotating field behaves as circle swimmers. • Diffusion coefficient of these swimmers due to the random switching of rotary motors is calculated. • Results are in good qualitative and quantitative agreement with available experimental results

  15. Non-Uniform Heat Transfer in Thermal Regenerators

    Jensen, Jesper Buch

    regenerators (AMRs) with parallel plates. The results suggest that random variations in the regenerator geometries causes maldistributed fluid flow inside the regener- ators, which affects the regenerator performance. In order to study the heat transfer processes in regenerators with non-uniform geometries, a...... numerical model, which simulates a single-blow operation in a parallel-plate regenerator, was developed and used to model the heat transfer under various conditions. In addition to the modeling of the heat transfer, a series of experiments on passive regenerators with non-uniform, but precisely controlled......This thesis presents investigations on the heat transfer in complex heat ex- changers in general and in regenerative heat exchangers (regenerators) in par- ticular. The motivation for this work is a result of inconsistencies obeserved in the results from a series of experiments on active magnetic...

  16. Transcriptomic analysis of tail regeneration in the lizard Anolis carolinensis reveals activation of conserved vertebrate developmental and repair mechanisms.

    Elizabeth D Hutchins

    Full Text Available Lizards, which are amniote vertebrates like humans, are able to lose and regenerate a functional tail. Understanding the molecular basis of this process would advance regenerative approaches in amniotes, including humans. We have carried out the first transcriptomic analysis of tail regeneration in a lizard, the green anole Anolis carolinensis, which revealed 326 differentially expressed genes activating multiple developmental and repair mechanisms. Specifically, genes involved in wound response, hormonal regulation, musculoskeletal development, and the Wnt and MAPK/FGF pathways were differentially expressed along the regenerating tail axis. Furthermore, we identified 2 microRNA precursor families, 22 unclassified non-coding RNAs, and 3 novel protein-coding genes significantly enriched in the regenerating tail. However, high levels of progenitor/stem cell markers were not observed in any region of the regenerating tail. Furthermore, we observed multiple tissue-type specific clusters of proliferating cells along the regenerating tail, not localized to the tail tip. These findings predict a different mechanism of regeneration in the lizard than the blastema model described in the salamander and the zebrafish, which are anamniote vertebrates. Thus, lizard tail regrowth involves the activation of conserved developmental and wound response pathways, which are potential targets for regenerative medical therapies.

  17. Transcriptomic analysis of tail regeneration in the lizard Anolis carolinensis reveals activation of conserved vertebrate developmental and repair mechanisms.

    Hutchins, Elizabeth D; Markov, Glenn J; Eckalbar, Walter L; George, Rajani M; King, Jesse M; Tokuyama, Minami A; Geiger, Lauren A; Emmert, Nataliya; Ammar, Michael J; Allen, April N; Siniard, Ashley L; Corneveaux, Jason J; Fisher, Rebecca E; Wade, Juli; DeNardo, Dale F; Rawls, J Alan; Huentelman, Matthew J; Wilson-Rawls, Jeanne; Kusumi, Kenro

    2014-01-01

    Lizards, which are amniote vertebrates like humans, are able to lose and regenerate a functional tail. Understanding the molecular basis of this process would advance regenerative approaches in amniotes, including humans. We have carried out the first transcriptomic analysis of tail regeneration in a lizard, the green anole Anolis carolinensis, which revealed 326 differentially expressed genes activating multiple developmental and repair mechanisms. Specifically, genes involved in wound response, hormonal regulation, musculoskeletal development, and the Wnt and MAPK/FGF pathways were differentially expressed along the regenerating tail axis. Furthermore, we identified 2 microRNA precursor families, 22 unclassified non-coding RNAs, and 3 novel protein-coding genes significantly enriched in the regenerating tail. However, high levels of progenitor/stem cell markers were not observed in any region of the regenerating tail. Furthermore, we observed multiple tissue-type specific clusters of proliferating cells along the regenerating tail, not localized to the tail tip. These findings predict a different mechanism of regeneration in the lizard than the blastema model described in the salamander and the zebrafish, which are anamniote vertebrates. Thus, lizard tail regrowth involves the activation of conserved developmental and wound response pathways, which are potential targets for regenerative medical therapies. PMID:25140675

  18. Magnetic Helicity Injection in Solar Active Regions

    Hong-Qi Zhang

    2006-01-01

    We present the evolution of magnetic field and its relationship with magnetic (current) helicity in solar active regions from a series of photospheric vector magnetograms obtained by Huairou Solar Observing Station, longitudinal magnetograms by MDI of SOHO and white light images of TRACE. The photospheric current helicity density is a quantity reflecting the local twisted magnetic field and is related to the remaining magnetic helicity in the photosphere, even if the mean current helicity density brings the general chiral property in a layer of solar active regions. As new magnetic flux emerges in active regions, changes of photospheric current helicity density with the injection of magnetic helicity into the corona from the subatmosphere can be detected, including changes in sign caused by the injection of magnetic helicity of opposite sign. Because the injection rate of magnetic helicity and photospheric current helicity density have different means in the solar atmosphere,the injected magnetic helicity is probably not proportional to the current helicity density remaining in the photosphere. The evidence is that rotation of sunspots does not synchronize exactly with the twist of photospheric transverse magnetic field in some active regions (such as, delta active regions). They represent different aspects of magnetic chirality. A combined analysis of the observational magnetic helicity parameters actually provides a relative complete picture of magnetic helicity and its transfer in the solar atmosphere.

  19. Impact of Cylinder Deactivation on Active Diesel Particulate Filter Regeneration at Highway Cruise Conditions

    Xueting eLu

    2015-08-01

    Full Text Available Abstract—Heavy-duty over-the-road trucks require periodic active diesel particulate filter regeneration to clean the filter of stored particulate matter. These events require sustained temperatures between 500 and 600□C to complete the regeneration process. Engine operation during typical 65 mile/hour highway cruise conditions (1200 rpm/7.6 bar results in temperatures of approximately 350□C, and can reach approximately 420□C with late fuel injection. This necessitates hydrocarbon fueling of a diesel oxidation catalyst or burner located upstream of the diesel particulate filter to reach the required regeneration temperatures. These strategies require increased fuel consumption, and the presence of a fuel-dosed oxidation catalyst (or burner between the engine and particulate filter. This paper experimentally demonstrates that, at the highway cruise condition, deactivation of valve motions and fuel injection for two or three (of six cylinders can instead be used to reach engine outlet temperatures of 520-570□C, a 170-220□C increase compared to normal operation. This is primarily a result of a reduction in the air-to-fuel ratio realized by reducing the displaced cylinder volume through cylinder deactivation.

  20. Optically-Induced Neuronal Activity Is Sufficient to Promote Functional Motor Axon Regeneration In Vivo

    Ward, Patricia J.; Jones, Laura N.; Mulligan, Amanda; Goolsby, William; Wilhelm, Jennifer C.; English, Arthur W.

    2016-01-01

    Peripheral nerve injuries are common, and functional recovery is very poor. Beyond surgical repair of the nerve, there are currently no treatment options for these patients. In experimental models of nerve injury, interventions (such as exercise and electrical stimulation) that increase neuronal activity of the injured neurons effectively enhance axon regeneration. Here, we utilized optogenetics to determine whether increased activity alone is sufficient to promote motor axon regeneration. In thy-1-ChR2/YFP transgenic mice in which a subset of motoneurons express the light-sensitive cation channel, channelrhodopsin (ChR2), we activated axons in the sciatic nerve using blue light immediately prior to transection and surgical repair of the sciatic nerve. At four weeks post-injury, direct muscle EMG responses evoked with both optical and electrical stimuli as well as the ratio of these optical/electrical evoked EMG responses were significantly greater in mice that received optical treatment. Thus, significantly more ChR2+ axons successfully re-innervated the gastrocnemius muscle in mice that received optical treatment. Sections of the gastrocnemius muscles were reacted with antibodies to Synaptic Vesicle Protein 2 (SV2) to quantify the number of re-occupied motor endplates. The number of SV2+ endplates was greater in mice that received optical treatment. The number of retrogradely-labeled motoneurons following intramuscular injection of cholera toxin subunit B (conjugated to Alexa Fluor 555) was greater in mice that received optical treatment. Thus, the acute (1 hour), one-time optical treatment resulted in robust, long-lasting effects compared to untreated animals as well as untreated axons (ChR2-). We conclude that neuronal activation is sufficient to promote motor axon regeneration, and this regenerative effect is specific to the activated neurons. PMID:27152611

  1. Optically-Induced Neuronal Activity Is Sufficient to Promote Functional Motor Axon Regeneration In Vivo.

    Ward, Patricia J; Jones, Laura N; Mulligan, Amanda; Goolsby, William; Wilhelm, Jennifer C; English, Arthur W

    2016-01-01

    Peripheral nerve injuries are common, and functional recovery is very poor. Beyond surgical repair of the nerve, there are currently no treatment options for these patients. In experimental models of nerve injury, interventions (such as exercise and electrical stimulation) that increase neuronal activity of the injured neurons effectively enhance axon regeneration. Here, we utilized optogenetics to determine whether increased activity alone is sufficient to promote motor axon regeneration. In thy-1-ChR2/YFP transgenic mice in which a subset of motoneurons express the light-sensitive cation channel, channelrhodopsin (ChR2), we activated axons in the sciatic nerve using blue light immediately prior to transection and surgical repair of the sciatic nerve. At four weeks post-injury, direct muscle EMG responses evoked with both optical and electrical stimuli as well as the ratio of these optical/electrical evoked EMG responses were significantly greater in mice that received optical treatment. Thus, significantly more ChR2+ axons successfully re-innervated the gastrocnemius muscle in mice that received optical treatment. Sections of the gastrocnemius muscles were reacted with antibodies to Synaptic Vesicle Protein 2 (SV2) to quantify the number of re-occupied motor endplates. The number of SV2+ endplates was greater in mice that received optical treatment. The number of retrogradely-labeled motoneurons following intramuscular injection of cholera toxin subunit B (conjugated to Alexa Fluor 555) was greater in mice that received optical treatment. Thus, the acute (1 hour), one-time optical treatment resulted in robust, long-lasting effects compared to untreated animals as well as untreated axons (ChR2-). We conclude that neuronal activation is sufficient to promote motor axon regeneration, and this regenerative effect is specific to the activated neurons. PMID:27152611

  2. Optically-Induced Neuronal Activity Is Sufficient to Promote Functional Motor Axon Regeneration In Vivo.

    Patricia J Ward

    Full Text Available Peripheral nerve injuries are common, and functional recovery is very poor. Beyond surgical repair of the nerve, there are currently no treatment options for these patients. In experimental models of nerve injury, interventions (such as exercise and electrical stimulation that increase neuronal activity of the injured neurons effectively enhance axon regeneration. Here, we utilized optogenetics to determine whether increased activity alone is sufficient to promote motor axon regeneration. In thy-1-ChR2/YFP transgenic mice in which a subset of motoneurons express the light-sensitive cation channel, channelrhodopsin (ChR2, we activated axons in the sciatic nerve using blue light immediately prior to transection and surgical repair of the sciatic nerve. At four weeks post-injury, direct muscle EMG responses evoked with both optical and electrical stimuli as well as the ratio of these optical/electrical evoked EMG responses were significantly greater in mice that received optical treatment. Thus, significantly more ChR2+ axons successfully re-innervated the gastrocnemius muscle in mice that received optical treatment. Sections of the gastrocnemius muscles were reacted with antibodies to Synaptic Vesicle Protein 2 (SV2 to quantify the number of re-occupied motor endplates. The number of SV2+ endplates was greater in mice that received optical treatment. The number of retrogradely-labeled motoneurons following intramuscular injection of cholera toxin subunit B (conjugated to Alexa Fluor 555 was greater in mice that received optical treatment. Thus, the acute (1 hour, one-time optical treatment resulted in robust, long-lasting effects compared to untreated animals as well as untreated axons (ChR2-. We conclude that neuronal activation is sufficient to promote motor axon regeneration, and this regenerative effect is specific to the activated neurons.

  3. Connection between active longitudes and magnetic helicity

    Brandenburg, A

    2005-01-01

    A two-dimensional mean field dynamo model is solved where magnetic helicity conservation is fully included. The model has a negative radial velocity gradient giving rise to equatorward migration of magnetic activity patterns. In addition the model develops longitudinal variability with activity patches travelling in longitude. These patches may be associated with active longitudes.

  4. Tunable reflector with active magnetic metamaterials.

    Deng, Tianwei; Huang, Ruifeng; Tang, Ming-Chun; Tan, Peng Khiang

    2014-03-24

    We placed active magnetic metamaterials on metallic surface to implement a tunable reflector with excellent agile performance. By incorporating active elements into the unit cells of the magnetic metamaterial, this active magnetic metamaterial can be tuned to switch function of the reflector among a perfect absorber, a perfect reflector and a gain reflector. This brings about DC control lines to electrically tune the active magnetic metamaterial with positive loss, zero loss and even negative loss. The design, analytical and numerical simulation methods, and experimental results of the tunable reflector are presented. PMID:24663977

  5. Superconducting magnet activities at CEN Saclay

    The activities in superconducting magnets at DPhPE/Saclay spread over a wide range from DC magnets mainly for particle and nuclear physics and also for other fields of research, pulsed magnets for particle accelerators and for a controlled fusion tokamak machine. The superconducting magnets designed during recent years involve a variety of conductor types, winding schemes, materials and cooling modes, including the use of superfluid helium. (author)

  6. Regeneration of the iodine isotope-exchange efficiency for nuclear-grade activated carbons

    The removal of radioactive iodine from air flows passing through impregnated activated carbons depends on a minimum of three distinguishable reactions: (1) adsorption on the carbon networks of the activated carbons, (2) iodine isotope exchange with impregnated iodine-127, and (3) chemical combination with impregnated tertiary amines when present. When a carbon is new, all three mechanisms are at peak performance and it is not possible to distinguish among the three reactions by a single measurement; the retention of methyl iodide-127 is usually equal to the retention of methyl iodide-131. After the carbon is placed in service, the three mechanisms of iodine removal are degraded by the contaminants of the air at different rates; the adsorption process degrades faster than the other two. This behavior will be shown by comparisons of methyl iodide-127 and methyl iodide-131 penetration tests. It was found possible to regenerate the iodine isotope-exchange efficiency by reaction with airborne chemical reducing agents with little or no improvement in methyl iodine-127 retention. Examples will be given of the chemical regeneration of carbons after exhaustion with known contaminants as well as for many carbons removed from nuclear power operations. The depth profile of methyl iodide-131 penetration was determined in 2-inch deep layers before and after chemical treatments

  7. Thermally activated magnetization reversal in magnetic tunnel junctions

    Zhou Guang-Hong; Wang Yin-Gang; Qi Xian-Jin; Li Zi-Quan; Chen Jian-Kang

    2009-01-01

    In this paper, the magnetization reversal of the ferromagnetic layers in the lrMn/CoFe/AlOx/CoFe magnetic tunnel junction has been investigated using bulk magnetometry. The films exhibit very complex magnetization processes and reversal mechanism. Thermal activation phenomena such as the training effect, the asymmetry of reversal, the loop broadening and the decrease of exchange field while holding the film at negative saturation have been observed on the hysteresis loops of the pinned ferromagnetic layer while not on those of the free ferromagnetic layer. The thermal activation phenomena observed can be explained by the model of two energy barrier distributions with different time constants.

  8. The Magnetic Free Energy in Active Regions

    Metcalf, Thomas R.; Mickey, Donald L.; LaBonte, Barry J.

    2001-01-01

    The magnetic field permeating the solar atmosphere governs much of the structure, morphology, brightness, and dynamics observed on the Sun. The magnetic field, especially in active regions, is thought to provide the power for energetic events in the solar corona, such as solar flares and Coronal Mass Ejections (CME) and is believed to energize the hot coronal plasma seen in extreme ultraviolet or X-rays. The question remains what specific aspect of the magnetic flux governs the observed variability. To directly understand the role of the magnetic field in energizing the solar corona, it is necessary to measure the free magnetic energy available in active regions. The grant now expiring has demonstrated a new and valuable technique for observing the magnetic free energy in active regions as a function of time.

  9. Active Achilles tendon kinesitherapy accelerates Achilles tendon repair by promoting neurite regeneration

    Jiasharete Jielile; Beicen Hunapia; Ayidaer Jialihasi; Jingping Bai; Murat Kizaibek; Minawa Aibai; Gulnur Sabirhazi; Nuerai Shawutali; Wulanbai Tangkejie; Aynaz Badelhan; Yeermike Nuerduola; Turde Satewalede; Darehan Buranbai

    2012-01-01

    Active Achilles tendon kinesitherapy facilitates the functional recovery of a ruptured Achilles tendon. However, protein expression during the healing process remains a controversial issue. New Zealand rabbits, aged 14 weeks, underwent tenotomy followed immediately by Achilles tendon microsurgery to repair the Achilles tendon rupture. The tendon was then immobilized or subjected to postoperative early motion treatment (kinesitherapy). Mass spectrography results showed that after 14 days of motion treatment, 18 protein spots were differentially expressed, among which, 12 were up-regulated, consisting of gelsolin isoform b and neurite growth-related protein collapsing response mediator protein 2. Western blot analysis showed that gelsolin isoform b was up-regulated at days 7–21 of motion treatment. These findings suggest that active Achilles tendon kinesitherapy promotes the neurite regeneration of a ruptured Achilles tendon and gelsolin isoform b can be used as a biomarker for Achilles tendon healing after kinesitherapy.

  10. Detection of hydroxyl radicals during regeneration of granular activated carbon in dielectric barrier discharge plasma system

    To understand the reactions taking place in the dielectric barrier discharge (DBD) plasma system of activated carbon regeneration, the determination of active species is necessary. A method based on High Performance Liquid Chromatography with radical trapping by salicylic acid, has been developed to measure hydroxyl radical (.OH) in the DBD plasma reactor. The effects of applied voltage, treatment time, and gas flow rate and atmosphere were investigated. Experimental results indicated that increasing voltage, treatment time and air flow rate could enhance the formation of .OH. Oxygen atmosphere and a suitable GAC water content were contributed to .OH generation. The results give an insight into plasma chemical processes, and can be helpful to optimize the design and application for the plasma system.

  11. Investigation on the two-stage active magnetic regenerative refrigerator for liquefaction of hydrogen

    Park, Inmyong; Park, Jiho; Jeong, Sangkwon [Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); Kim, Youngkwon [Institute for Basic Science, Daejeon 305-811 (Korea, Republic of)

    2014-01-29

    An active magnetic regenerative refrigerator (AMRR) is expected to be useful for hydrogen liquefaction due to its inherent high thermodynamic efficiency. Because the temperature of the cold end of the refrigerator has to be approximately liquid temperature, a large temperature span of the active magnetic regenerator (AMR) is indispensable when the heat sink temperature is liquid nitrogen temperature or higher. Since magnetic refrigerants are only effective in the vicinity of their own transition temperatures, which limit the temperature span of the AMR, an innovative structure is needed to increase the temperature span. The AMR must be a layered structure and the thermophysical matching of magnetic field and flow convection effects is very important. In order to design an AMR for liquefaction of hydrogen, the implementation of multi-layered AMR with different magnetic refrigerants is explored with multi-staging. In this paper, the performance of the multi-layered AMR using four rare-earth compounds (GdNi{sub 2}, Gd{sub 0.1}Dy{sub 0.9}Ni{sub 2}, Dy{sub 0.85}Er{sub 0.15}Al{sub 2}, Dy{sub 0.5}Er{sub 0.5}Al{sub 2}) is investigated. The experimental apparatus includes two-stage active magnetic regenerator containing two different magnetic refrigerants each. A liquid nitrogen reservoir connected to the warm end of the AMR maintains the temperature of the warm end around 77 K. High-pressure helium gas is employed as a heat transfer fluid in the AMR and the maximum magnetic field of 4 T is supplied by the low temperature superconducting (LTS) magnet. The temperature span with the variation of parameters such as phase difference between magnetic field and mass flow rate of magnetic refrigerants in AMR is investigated. The maximum temperature span in the experiment is recorded as 50 K and several performance issues have been discussed in this paper.

  12. Investigation on the two-stage active magnetic regenerative refrigerator for liquefaction of hydrogen

    An active magnetic regenerative refrigerator (AMRR) is expected to be useful for hydrogen liquefaction due to its inherent high thermodynamic efficiency. Because the temperature of the cold end of the refrigerator has to be approximately liquid temperature, a large temperature span of the active magnetic regenerator (AMR) is indispensable when the heat sink temperature is liquid nitrogen temperature or higher. Since magnetic refrigerants are only effective in the vicinity of their own transition temperatures, which limit the temperature span of the AMR, an innovative structure is needed to increase the temperature span. The AMR must be a layered structure and the thermophysical matching of magnetic field and flow convection effects is very important. In order to design an AMR for liquefaction of hydrogen, the implementation of multi-layered AMR with different magnetic refrigerants is explored with multi-staging. In this paper, the performance of the multi-layered AMR using four rare-earth compounds (GdNi2, Gd0.1Dy0.9Ni2, Dy0.85Er0.15Al2, Dy0.5Er0.5Al2) is investigated. The experimental apparatus includes two-stage active magnetic regenerator containing two different magnetic refrigerants each. A liquid nitrogen reservoir connected to the warm end of the AMR maintains the temperature of the warm end around 77 K. High-pressure helium gas is employed as a heat transfer fluid in the AMR and the maximum magnetic field of 4 T is supplied by the low temperature superconducting (LTS) magnet. The temperature span with the variation of parameters such as phase difference between magnetic field and mass flow rate of magnetic refrigerants in AMR is investigated. The maximum temperature span in the experiment is recorded as 50 K and several performance issues have been discussed in this paper

  13. Sustained ERK Activation Underlies Reprogramming in Regeneration-Competent Salamander Cells and Distinguishes Them from Their Mammalian Counterparts

    Yun, Maximina H.; Gates, Phillip B.; Brockes, Jeremy P.

    2014-01-01

    Summary In regeneration-competent vertebrates, such as salamanders, regeneration depends on the ability of various differentiated adult cell types to undergo natural reprogramming. This ability is rarely observed in regeneration-incompetent species such as mammals, providing an explanation for their poor regenerative potential. To date, little is known about the molecular mechanisms mediating natural reprogramming during regeneration. Here, we have identified the extent of extracellular signal-regulated kinase (ERK) activation as a key component of such mechanisms. We show that sustained ERK activation following serum induction is required for re-entry into the cell cycle of postmitotic salamander muscle cells, partially by promoting the downregulation of p53 activity. Moreover, ERK activation induces epigenetic modifications and downregulation of muscle-specific genes such as Sox6. Remarkably, while long-term ERK activation is found in salamander myotubes, only transient activation is seen in their mammalian counterparts, suggesting that the extent of ERK activation could underlie differences in regenerative competence between species. PMID:25068118

  14. Gelatin crosslinked with dehydroascorbic acid as a novel scaffold for tissue regeneration with simultaneous antitumor activity

    A porous scaffold was developed to support normal tissue regeneration in the presence of residual tumor disease. It was prepared by gelatin crosslinked with dehydroascorbic acid (DHA). A physicochemical characterization of the scaffold was carried out. SEM and mercury porosimetry revealed a high porosity and interconnection of pores in the scaffold. Enzymatic degradation provided 56% weight loss in ten days. The scaffold was also evaluated in vitro for its ability to support the growth of normal cells while hindering tumor cell development. For this purpose, primary human fibroblasts and osteosarcoma tumor cells (MG-63) were seeded on the scaffold. Fibroblasts attached the scaffold and proliferated, while the tumor cells, after an initial attachment and growth, failed to proliferate and progressively underwent cell death. This was attributed to the progressive release of DHA during the scaffold degradation and its cytotoxic activity towards tumor cells. (paper)

  15. Bifurcations and intermittent magnetic activity

    The sequence of equilibria of two-dimensional reduced magnetohydrodynamics has been studied as a function of the tearing mode stability parameter Δ'. After a symmetry-breaking bifurcation occurring at Δ' ∼ 0, which originates a state with a small magnetic island, the system undergoes a second bifurcation, of tangent type, at Δ' ∼ 1. Above this value, no stationary solutions with small islands exist. The system rapidly develops an island of macroscopic size. This general property is proposed as a basic ingredient of the intermittent events observed in magnetically confined plasmas. (author)

  16. Bifurcations and intermittent magnetic activity

    Tebaldi, C.; Ottaviani, M.; Porcelli, F. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking

    1996-04-01

    The sequence of equilibria of two-dimensional reduced magnetohydrodynamics has been studied as a function of the tearing mode stability parameter {Delta}`. After a symmetry-breaking bifurcation occurring at {Delta}` {approx} 0, which originates a state with a small magnetic island, the system undergoes a second bifurcation, of tangent type, at {Delta}` {approx} 1. Above this value, no stationary solutions with small islands exist. The system rapidly develops an island of macroscopic size. This general property is proposed as a basic ingredient of the intermittent events observed in magnetically confined plasmas. (author).

  17. MAGNET

    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...

  18. Observational Study of Solar Magnetic Active Phenomena

    Hongqi Zhang

    2006-06-01

    The electric current separated into two parts reflected the quantative properties of heterogeneity and chirality of magnetic field, and defined them as the shear and twist components of current. We analyze the basic configuration and evolution of superactive region NOAA 6580-6619-6659. It is found that the contribution of the twist component of current cannot be reflected in the normal analysis of the magnetic shear and gradient of the active regions. The observational evidence of kink magnetic ropes generated from the subatmosphere cannot be found completely in some super delta active regions.

  19. Axon Regeneration Is Regulated by Ets–C/EBP Transcription Complexes Generated by Activation of the cAMP/Ca2+ Signaling Pathways

    Li, Chun; Hisamoto, Naoki; Matsumoto, Kunihiro

    2015-01-01

    The ability of specific neurons to regenerate their axons after injury is governed by cell-intrinsic regeneration pathways. In Caenorhabditis elegans, the JNK and p38 MAPK pathways are important for axon regeneration. Axonal injury induces expression of the svh-2 gene encoding a receptor tyrosine kinase, stimulation of which by the SVH-1 growth factor leads to activation of the JNK pathway. Here, we identify ETS-4 and CEBP-1, related to mammalian Ets and C/EBP, respectively, as transcriptiona...

  20. The physico-chemical properties and biostimulative activities of humic substances regenerated from lignite.

    David, Jan; Smejkalová, Daniela; Hudecová, Sárka; Zmeškal, Oldřich; von Wandruszka, Ray; Gregor, Tomáš; Kučerík, Jiří

    2014-01-01

    The positive effect of humic acids on the growth of plant roots is well known, however, the mechanisms and role of their physical structure in these processes have not been fully explained yet. In this work, South-Moravian lignite was oxidized by means of nitric acid and hydrogen peroxide to produce a set of regenerated humic acids. The elemental composition, solid state stability and solution characteristics were determined and correlated in vitro with their biological activity. A modified hydroponic method was applied to determine the effects of their potassium salts on Zea mays seedlings roots with respect to the plant weight, root length, root division, and starch and protein content. The relations between the determined parameters were evaluated through Principal Component Analysis and Pearson's correlation coefficients. The results indicated that the most important factor determining the biological activity of South-Moravian lignite potassium humates is related to the nature of self-assemblies, while the chemical composition had no direct connection with the root growth of Zea mays seedlings. It was demonstrated a controlled processing that provided humic substances with different chemical and physicochemical properties and variable biological activity. PMID:24790812

  1. A flexible numerical model to study an active magnetic refrigerator for near room temperature applications

    Aprea, Ciro; Maiorino, Angelo [Department of Mechanical Engineering, University of Salerno, Via Ponte Don Melillo 1, 84084 Fisciano (Salerno) (Italy)

    2010-08-15

    Magnetic refrigeration is an emerging technology based on the magnetocaloric effect in solid-state refrigerants. This technology offers a smaller global environmental impact than the refrigeration obtained by means of the classical vapor compression machines operating with fluids such as HFCs. The Active Magnetic Regenerative Refrigeration (AMRR) is currently the most studied ant tested magnetic cycle. It combines the regenerative properties of a high specific heat solid porous matrix with the ability of performing thermo-magnetic cycles thanks to the magnetocaloric property of the refrigerant; while a fluid pulsing through the regenerator works as a heat transfer medium. An active magnetic regenerator can provide larger temperature spans making up for the local small temperature variation of the refrigerant. In the present paper, a practical model for predicting the performance and efficiency of an AMRR cycle has been developed. The model evaluates both the refrigerant properties and the entire cycle of an AMR operating in conformity with a Brayton regenerative cycle. The magnetocaloric material of choice is gadolinium, while the heat transfer medium is liquid water. With this model can be predicted the refrigeration capacity, the power consumption and consequently the Coefficient of Performance. The results show a greater COP when compared to a classical vapor compression plant working between the same temperature levels. (author)

  2. A flexible numerical model to study an active magnetic refrigerator for near room temperature applications

    Magnetic refrigeration is an emerging technology based on the magnetocaloric effect in solid-state refrigerants. This technology offers a smaller global environmental impact than the refrigeration obtained by means of the classical vapor compression machines operating with fluids such as HFCs. The Active Magnetic Regenerative Refrigeration (AMRR) is currently the most studied ant tested magnetic cycle. It combines the regenerative properties of a high specific heat solid porous matrix with the ability of performing thermo-magnetic cycles thanks to the magnetocaloric property of the refrigerant; while a fluid pulsing through the regenerator works as a heat transfer medium. An active magnetic regenerator can provide larger temperature spans making up for the local small temperature variation of the refrigerant. In the present paper, a practical model for predicting the performance and efficiency of an AMRR cycle has been developed. The model evaluates both the refrigerant properties and the entire cycle of an AMR operating in conformity with a Brayton regenerative cycle. The magnetocaloric material of choice is gadolinium, while the heat transfer medium is liquid water. With this model can be predicted the refrigeration capacity, the power consumption and consequently the Coefficient of Performance. The results show a greater COP when compared to a classical vapor compression plant working between the same temperature levels.

  3. Magnetic biodegradable Fe{sub 3}O{sub 4}/CS/PVA nanofibrous membranes for bone regeneration

    Wei Yan; Zhang Xuehui; Hu Xiaoyang; Deng Xuliang [Department of Geriatric Dentistry, School and Hospital of Stomatology, Peking University, Beijing, 100081 (China); Song Yu; Lin Yuanhua [State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China); Han Bing [Department of Orthodontics, School and Hospital of Stomatology, Peking University, Beijing, 100081 (China); Wang Xinzhi, E-mail: kqdengxuliang@bjmu.edu.cn [Department of Prosthodontics, School and Hospital of Stomatology, Peking University, Beijing, 100081 (China)

    2011-10-15

    In recent years, interest in magnetic biomimetic scaffolds for tissue engineering has increased considerably. The aim of this study is to develop magnetic biodegradable fibrous materials with potential use in bone regeneration. Magnetic biodegradable Fe{sub 3}O{sub 4}/chitosan (CS)/poly vinyl alcohol (PVA) nanofibrous membranes were achieved by electrospinning with average fiber diameters ranging from 230 to 380 nm and porosity of 83.9-85.1%. The influences of polymer concentration, applied voltage and Fe{sub 3}O{sub 4} nanoparticles loading on the fabrication of nanofibers were investigated. The polymer concentration of 4.5 wt%, applied voltage of 20 kV and Fe{sub 3}O{sub 4} nanoparticles loading of lower than 5 wt% could produce homogeneous, smooth and continuous Fe{sub 3}O{sub 4}/CS/PVA nanofibrous membranes. X-ray diffraction (XRD) data confirmed that the crystalline structure of the Fe{sub 3}O{sub 4}, CS and PVA were maintained during electrospinning process. Fourier transform infrared spectroscopy (FT-IR) demonstrated that the Fe{sub 3}O{sub 4} loading up to 5 wt% did not change the functional groups of CS/PVA greatly. Transmission electron microscopy (TEM) showed islets of Fe{sub 3}O{sub 4} nanoparticles evenly distributed in the fibers. Weak ferrimagnetic behaviors of membranes were revealed by vibrating sample magnetometer (VSM) test. Tensile test exhibited Young's modulus of membranes that were gradually enhanced with the increase of Fe{sub 3}O{sub 4} nanoparticles loading, while ultimate tensile stress and ultimate strain were slightly reduced by Fe{sub 3}O{sub 4} nanoparticles loading of 5%. Additionally, MG63 human osteoblast-like cells were seeded on the magnetic nanofibrous membranes to evaluate their bone biocompatibility. Cell growth dynamics according to MTT assay and scanning electron microscopy (SEM) observation exhibited good cell adhesion and proliferation, suggesting that this magnetic biodegradable Fe{sub 3}O{sub 4}/CS/PVA nanofibrous

  4. International program activities in magnetic fusion energy

    The following areas of our international activities in magnetic fusion are briefly described: (1) policy; (2) background; (3) strategy; (4) strategic considerations and concerns; (5) domestic program inplications, and (6) implementation. The current US activities are reviewed. Some of our present program needs are outlined

  5. Doppler-free magnetic optical activity

    Giraud-Cotton, S.; Kaftandjian, V.P.; Talin, B.

    1980-01-01

    The theory of Doppler-free magnetic optical activity associated with a single absorption line is presented. The transmission of tunable laser light, linearly polarized, through a dilute gaseous medium along a steady magnetic field is studied in the presence of a second counterpropagating saturating laser. The third order non linear susceptibility is calculated for a two-level system exhibiting a normal Zeeman effect, with arbitrary J values.

  6. 电子束再生粉状活性炭的研究%Study on Regeneration of Powdered Activated Carbon by Electron Beam

    吴明红; 包伯荣; 陈捷; 陆丽蓉

    2000-01-01

    The powdered activated carbon which had adsorbed phenylglycine solution from pharmaceutics factory can be regenerated by mean of irradiation of high-energy electron beams in oxygen, nitrogen and water vapor respectively. The effects of radiation dose and beam current on regeneration of activated carbon in different atmosphere were studied. Differential scanning calorimetry (DSC) and the iodine number of activated carbon were used to monitor the change of carbon adsorption. The results show that the powder activated carbon polluted with phenlglycine could be regenerated effectively by irradiation of high energy electron beams in nitrogen stream. The generation did not need high temperature, and the weight loss of carbon and energy consumption were minimum.

  7. Study on Regeneration of Powdered Activated Carbon by Electron Beam%电子束再生粉状活性炭的研究

    吴明红; 包伯荣; 陈捷; 陆丽蓉

    2001-01-01

    The powdered activated carbon which had adsorbed phenylglycine solution from pharmaceutics factory can be regenerated by mean of irradiation of high-energy electron beams in oxygen, nitrogen and water vapor respectively. The effects of radiation dose and beam current on regeneration of activated carbon in different atmosphere were studied. Differential scanning calorimetry (DSC) and the iodine number of activated carbon were used to monitor the change of carbon adsorption. The results show that the powder activated carbon polluted with phenlglycine could be regenerated effectively by irradiation of high energy electron beams in nitrogen stream. The generation did not need high temperature, and the weight loss of carbon and energy consumption were minimum.

  8. Procyanidins Negatively Affect the Activity of the Phosphatases of Regenerating Liver.

    Sven Stadlbauer

    Full Text Available Natural polyphenols like oligomeric catechins (procyanidins derived from green tea and herbal medicines are interesting compounds for pharmaceutical research due to their ability to protect against carcinogenesis in animal models. It is nevertheless still unclear how intracellular pathways are modulated by polyphenols. Monomeric polyphenols were shown to affect the activity of some protein phosphatases (PPs. The three phosphatases of regenerating liver (PRLs are close relatives and promising therapeutic targets in cancer. In the present study we show that several procyanidins inhibit the activity of all three members of the PRL family in the low micromolar range, whereas monomeric epicatechins show weak inhibitory activity. Increasing the number of catechin units in procyanidins to more than three does not further enhance the potency. Remarkably, the tested procyanidins showed selectivity in vitro when compared to other PPs, and over 10-fold selectivity toward PRL-1 over PRL-2 and PRL-3. As PRL overexpression induces cell migration compared to control cells, the effect of procyanidins on this phenotype was studied. Treatment with procyanidin C2 led to a decrease in cell migration of PRL-1- and PRL-3-overexpressing cells, suggesting the compound-dependent inhibition of PRL-promoted cell migration. Treatment with procyanidin B3 led to selective suppression of PRL-1 overexpressing cells, thereby corroborating the selectivity toward PRL-1- over PRL-3 in vitro. Together, our results show that procyanidins negatively affect PRL activity, suggesting that PRLs could be targets in the polypharmacology of natural polyphenols. Furthermore, they are interesting candidates for the development of PRL-1 inhibitors due to their low cellular toxicity and the selectivity within the PRL family.

  9. Activation of pancreatic-duct-derived progenitor cells during pancreas regeneration in adult rats

    Li, Wan-Chun; Rukstalis, J. Michael; Nishimura, Wataru; Tchipashvili, Vaja; Habener, Joel F.; Arun SHARMA; Bonner-Weir, Susan

    2010-01-01

    The adult pancreas has considerable capacity to regenerate in response to injury. We hypothesized that after partial pancreatectomy (Px) in adult rats, pancreatic-duct cells serve as a source of regeneration by undergoing a reproducible dedifferentiation and redifferentiation. We support this hypothesis by the detection of an early loss of the ductal differentiation marker Hnf6 in the mature ducts, followed by the transient appearance of areas composed of proliferating ductules, called foci o...

  10. Treatment of Reactive Black 5 by combined electrocoagulation-granular activated carbon adsorption-microwave regeneration process

    Treatment of an azo dye, Reactive Black 5 (RB5) by combined electrocoagulation-activated carbon adsorption-microwave regeneration process was evaluated. The toxicity was also monitored by the Vibrio fischeri light inhibition test. GAC of 100 g L-1 sorbed 82% of RB5 (100 mg L-1) within 4 h. RB5-loaded GAC was not effectively regenerated by microwave irradiation (800 W, 30 s). Electrocoagulation showed high decolorization of RB5 within 8 min at pH0 of 7, current density of 277 A m-2, and NaCl of 1 g L-1. However, 61% COD residue remained after treatment and toxicity was high (100% light inhibition). GAC of 20 g L-1 effectively removed COD and toxicity of electrocoagulation-treated solution within 4 h. Microwave irradiation effectively regenerated intermediate-loaded GAC within 30 s at power of 800 W, GAC/water ratio of 20 g L-1, and pH of 7.8. The adsorption capacity of GAC for COD removal from the electrocoagulation-treated solution did not significantly decrease at the first 7 cycles of adsorption/regeneration. The adsorption capacity of GAC for removal of both A265 (benzene-related groups) and toxicity slightly decreased after the 6th cycle.

  11. Treatment of Reactive Black 5 by combined electrocoagulation-granular activated carbon adsorption-microwave regeneration process

    Chang, Shih-Hsien, E-mail: shchang@csmu.edu.tw [Department of Public Health, Chung-Shan Medical University, 110 Chen-Kuo N. Road, Taichung 402, Taiwan (China); Wang, Kai-Sung; Liang, Hsiu-Hao; Chen, Hsueh-Yu; Li, Heng-Ching; Peng, Tzu-Huan [Department of Public Health, Chung-Shan Medical University, 110 Chen-Kuo N. Road, Taichung 402, Taiwan (China); Su, Yu-Chun; Chang, Chih-Yuan [Institute of Environmental Engineering, National Chiao-Tung University, Hsinchu, 300, Taiwan (China)

    2010-03-15

    Treatment of an azo dye, Reactive Black 5 (RB5) by combined electrocoagulation-activated carbon adsorption-microwave regeneration process was evaluated. The toxicity was also monitored by the Vibrio fischeri light inhibition test. GAC of 100 g L{sup -1} sorbed 82% of RB5 (100 mg L{sup -1}) within 4 h. RB5-loaded GAC was not effectively regenerated by microwave irradiation (800 W, 30 s). Electrocoagulation showed high decolorization of RB5 within 8 min at pH{sub 0} of 7, current density of 277 A m{sup -2}, and NaCl of 1 g L{sup -1}. However, 61% COD residue remained after treatment and toxicity was high (100% light inhibition). GAC of 20 g L{sup -1} effectively removed COD and toxicity of electrocoagulation-treated solution within 4 h. Microwave irradiation effectively regenerated intermediate-loaded GAC within 30 s at power of 800 W, GAC/water ratio of 20 g L{sup -1}, and pH of 7.8. The adsorption capacity of GAC for COD removal from the electrocoagulation-treated solution did not significantly decrease at the first 7 cycles of adsorption/regeneration. The adsorption capacity of GAC for removal of both A{sub 265} (benzene-related groups) and toxicity slightly decreased after the 6th cycle.

  12. Solar regeneration of powdered activated carbon impregnated with visible-light responsive photocatalyst: factors affecting performances and predictive model.

    Yap, Pow-Seng; Lim, Teik-Thye

    2012-06-01

    This study demonstrated a green technique to regenerate spent powdered activated carbon (AC) using solar photocatalysis. The AC was impregnated with a photocatalyst photoexcitable under visible-light irradiation to yield a solar regenerable composite, namely nitrogen-doped titanium dioxide (N-TiO(2)/AC). This composite exhibited bifunctional adsorptive-photocatalytic characteristics. Contaminants of emerging environmental concern, i.e. bisphenol-A (BPA), sulfamethazine (SMZ) and clofibric acid (CFA) which exhibited varying affinities for AC were chosen as target pollutants. The adsorption of BPA and SMZ by the N-TiO(2)/AC was significantly higher than that of CFA. The performance of solar photocatalytic regeneration (SPR) of the spent N-TiO(2)/AC composite generally increased with light intensity, N-TiO(2) loading and temperature. The regeneration efficiency (RE) for CFA-loaded spent composite was the highest compared to the other pollutant-loaded spent composites, achieving 77% within 8h of solar irradiation (765 W m(-2)). The rate-limiting process was pollutant desorption from the interior AC sorption sites. A kinetic model was developed to predict the transient concentration of the sorbate remaining in the spent composite during SPR. Comparison studies using solvent extraction technique indicated a different order of RE for the three pollutants, attributable to their varying solubilities in the aqueous and organic solvents. PMID:22464146

  13. Cluster magnetic fields from active galactic nuclei

    Sutter, P M; Yang, H -Y

    2009-01-01

    Active galactic nuclei (AGN) found at the centers of clusters of galaxies are a possible source for weak cluster-wide magnetic fields. To evaluate this scenario, we present 3D adaptive mesh refinement MHD simulations of a cool-core cluster that include injection of kinetic, thermal, and magnetic energy via an AGN-powered jet. Using the MHD solver in FLASH 2, we compare several sub-resolution approaches that link the estimated accretion rate as measured on the simulation mesh to the accretion rate onto the central black hole and the resulting feedback. We examine the effects of magnetized outflows on the accretion history of the black hole and discuss the ability of these models to magnetize the cluster medium.

  14. Mitochondrial aerobic respiration is activated during hair follicle stem cell differentiation, and its dysfunction retards hair regeneration

    Tang, Yan; Luo, Binping; Deng, Zhili; Wang, Ben; Liu, Fangfen; Li, Jinmao; Shi, Wei; Xie, Hongfu; Hu, Xingwang

    2016-01-01

    Background. Emerging research revealed the essential role of mitochondria in regulating stem/progenitor cell differentiation of neural progenitor cells, mesenchymal stem cells and other stem cells through reactive oxygen species (ROS), Notch or other signaling pathway. Inhibition of mitochondrial protein synthesis results in hair loss upon injury. However, alteration of mitochondrial morphology and metabolic function during hair follicle stem cells (HFSCs) differentiation and how they affect hair regeneration has not been elaborated upon. Methods. We compared the difference in mitochondrial morphology and activity between telogen bulge cells and anagen matrix cells. Expression levels of mitochondrial ROS and superoxide dismutase 2 (SOD2) were measured to evaluate redox balance. In addition, the level of pyruvate dehydrogenase kinase (PDK) and pyruvate dehydrogenase (PDH) were estimated to present the change in energetic metabolism during differentiation. To explore the effect of the mitochondrial metabolism on regulating hair regeneration, hair growth was observed after application of a mitochondrial respiratory inhibitor upon hair plucking. Results. During HFSCs differentiation, mitochondria became elongated with more abundant organized cristae and showed higher activity in differentiated cells. SOD2 was enhanced for redox balance with relatively stable ROS levels in differentiated cells. PDK increased in HFSCs while differentiated cells showed enhanced PDH, indicating that respiration switched from glycolysis to oxidative phosphorylation during differentiation. Inhibiting mitochondrial respiration in differentiated hair follicle cells upon hair plucking repressed hair regeneration in vivo. Conclusions. Upon HFSCs differentiation, mitochondria are elongated with more abundant cristae and show higher activity, accompanying with activated aerobic respiration in differentiated cells for higher energy supply. Also, dysfunction of mitochondrial respiration delays hair

  15. Heart Regeneration

    Laflamme, Michael A.; Charles E. Murry

    2011-01-01

    Heart failure plagues industrialized nations, killing more people than any other disease. Heart failure usually results from a deficiency of cardiomyocytes, and a robust therapy to regenerate lost myocardium could help millions of patients a year. Heart regeneration is well documented in lower vertebrates and in developing mammals. After we are born, however, human heart regeneration becomes limited. In this article, Laflamme and Murry review the innate barriers to heart regeneration, the evi...

  16. Cryogenic regenerators

    Importance of regenerators in cryogenic refrigerators is highlighted. Design aspects of regenerator are reviewed and the factors involved in the selection of regenerator material are enumerated. Various methods used to calculate the heat transfer coefficient and regenerator effectiveness are mentioned. Variation of effectiveness with various parameters is calculated by a computer programme using the ideal, Ackermann and Tipler formulae. Results are presented in graphical form. Listing of the computer programme is given in the Appendix. (author)

  17. Hybrid ground-source heat pump system with active air source regeneration

    Highlights: • A hybrid ground source heat pump system with two separate borefields is modelled. • The maximum underground storage temperature depends on the size of the drycooler. • Drycooler selection curves are given as function of underground storage temperature. • The size of the cold storage is reduced with 47% in the cost optimal configuration. • The cooling seasonal performance factor decreases with reduced storage capacity. - Abstract: Ground-source heat pump systems (GSHP) offer great advantages over traditional heating and cooling installations. However, their applications are limited due to the high initial costs of borehole drilling. One way to avoid these costs is by reducing the size of the borefield, e.g. by combining the system with other renewable energy sources or by using active regeneration to increase the system efficiency. In this paper a hybrid ground-source heat pump system (HGSHP) is analyzed. The borefield is split into a warm part and a cold part, which allows for seasonal thermal-energy storage. Additionally, supplementary drycoolers capture heat during summer and cold during winter. The relationship between the underground storage size and temperature and the drycooler capacity is described, using an office building in Flanders (Belgium) as reference case. Results show that with a HGSHP system a significant borefield size reduction can be achieved without compromising system performance; i.e. for the reference case a reduction of 47% was achieved in the cost-optimal configuration. It is also shown that the cooling seasonal performance factor decreases significantly with underground storage capacity. In addition, the HGSHP can be used to maintain or restore thermal balance in the geothermal source when heating and cooling loads do not match

  18. Regeneration of commercial SCR catalysts by washing and sulphation. Effect of sulphate groups on the activity

    Khodayari, R.; Ingemar Odenbrand, C.U. [Department of Chemical Engineering II, Lund University, P.O. Box 124, S-221 00 Lund (Sweden)

    2001-10-25

    The use of bio-fuels is becoming more important because of the environmental benefits associated with these fuels. Deactivation of SCR catalysts applied in bio-fuel plants is a major problem due to the high potassium content of bio-fuels and therefore, great potential lies in finding regeneration processes that can be used commercially. Exposing the catalyst surface to sulphate groups generated by SO{sub 2} or H{sub 2}SO{sub 4} is a promising way to rejuvenate the initial activity of the catalyst. The chemical stability of the sulphate groups was investigated by the interaction of the SCR reactant gases with the sulphate-promoted catalysts. Sulphate ions deposited on the surface of the TiO{sub 2}/V{sub 2}O{sub 5}/WO{sub 3} were thermally stable at 420C. The introduced sulphate groups were chemically unstable when the catalyst was treated with the SCR reactants at 400C, but were chemically stable when the catalyst was exposed for the SCR reactants at 350C. Sulphation after water treatment provided more chemically stable surface sulphate groups at 400C. The presence of sulphate groups enhanced the number and the strength of the surface acid sites. The amount of ammonia bound to the Broensted acid sites decreased with the potassium content of the catalyst while the amount of ammonia adsorbed on the Lewis acid sites was almost unaffected. Since potassium both retarded the redox potential of the surface vanadia species and decreased the amount of ammonia bound to the Broensted acid sites, it is important to wash the strongly deactivated catalyst before sulphation.

  19. TO THE METHOD OF THE STUDYING OF REGENERATION ACTIVITY OF GRAPE CUTTINGS (SCIENTIFIC-RESEARCH WORK ON BIOLOGY IN SECONDARY SCHOOLS

    Radchevskiy P. P.

    2014-09-01

    Full Text Available Methodological aspects of conduction of researches on study of regeneration activity of grape cuttings by students of secondary schools including by members of Small Agricultural Academy of Kuban are cited in the article

  20. mTOR signaling promotes stem cell activation via counterbalancing BMP-mediated suppression during hair regeneration.

    Deng, Zhili; Lei, Xiaohua; Zhang, Xudong; Zhang, Huishan; Liu, Shuang; Chen, Qi; Hu, Huimin; Wang, Xinyue; Ning, Lina; Cao, Yujing; Zhao, Tongbiao; Zhou, Jiaxi; Chen, Ting; Duan, Enkui

    2015-02-01

    Hair follicles (HFs) undergo cycles of degeneration (catagen), rest (telogen), and regeneration (anagen) phases. Anagen begins when the hair follicle stem cells (HFSCs) obtain sufficient activation cues to overcome suppressive signals, mainly the BMP pathway, from their niche cells. Here, we unveil that mTOR complex 1 (mTORC1) signaling is activated in HFSCs, which coincides with the HFSC activation at the telogen-to-anagen transition. By using both an inducible conditional gene targeting strategy and a pharmacological inhibition method to ablate or inhibit mTOR signaling in adult skin epithelium before anagen initiation, we demonstrate that HFs that cannot respond to mTOR signaling display significantly delayed HFSC activation and extended telogen. Unexpectedly, BMP signaling activity is dramatically prolonged in mTOR signaling-deficient HFs. Through both gain- and loss-of-function studies in vitro, we show that mTORC1 signaling negatively affects BMP signaling, which serves as a main mechanism whereby mTORC1 signaling facilitates HFSC activation. Indeed, in vivo suppression of BMP by its antagonist Noggin rescues the HFSC activation defect in mTORC1-null skin. Our findings reveal a critical role for mTOR signaling in regulating stem cell activation through counterbalancing BMP-mediated repression during hair regeneration. PMID:25609845

  1. Magnetic refrigerator for hydrogen liquefaction

    Matsumoto, Koichi; Kondo, T.; Yoshioka, S; Kamiya, K.; Numazawa, T.

    2009-01-01

    Magnetic refrigeration which is based on the magnetocaloric effect of solids has the potential to achieve high thermal efficiency for hydrogen liquefaction. We have been developing a magnetic refrigerator for hydrogen liquefaction which cools down hydrogen gas from liquid natural gas temperature and liquefies at 20 K. The magnetic liquefaction system consists of two magnetic refrigerators: Carnot magnetic refrigerator (CMR) and active magnetic regenerator (AMR) device. CMR with Carnot cycle s...

  2. mTOR is necessary for proper satellite cell activity and skeletal muscle regeneration

    The serine/threonine kinase mammalian target of rapamycin (mTOR) is a key regulator of protein synthesis, cell proliferation and energy metabolism. As constitutive deletion of Mtor gene results in embryonic lethality, the function of mTOR in muscle stem cells (satellite cells) and skeletal muscle regeneration remains to be determined. In this study, we established a satellite cell specific Mtor conditional knockout (cKO) mouse model by crossing Pax7CreER and Mtorflox/flox mice. Skeletal muscle regeneration after injury was severely compromised in the absence of Mtor, indicated by increased number of necrotic myofibers infiltrated by Evans blue dye, and reduced number and size of regenerated myofibers in the Mtor cKO mice compared to wild type (WT) littermates. To dissect the cellular mechanism, we analyzed satellite cell-derived primary myoblasts grown on single myofibers or adhered to culture plates. The Mtor cKO myoblasts exhibited defective proliferation and differentiation kinetics when compared to myoblasts derived from WT littermates. At the mRNA and protein levels, the Mtor cKO myoblasts expressed lower levels of key myogenic determinant genes Pax7, Myf5, Myod, Myog than did the WT myoblasts. These results suggest that mTOR is essential for satellite cell function and skeletal muscle regeneration through controlling the expression of myogenic genes. - Highlights: • Pax7CreER was used to delete Mtor gene in satellite cells. • Satellite cell specific deletion of Mtor impairs muscle regeneration. • mTOR is necessary for satellite cell proliferation and differentiation. • Deletion of Mtor leads to reduced expression of key myogenic genes

  3. mTOR is necessary for proper satellite cell activity and skeletal muscle regeneration

    Zhang, Pengpeng [Key Laboratory of Swine Genetics and Breeding of Agricultural Ministry & Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070 (China); Department of Animal Sciences, Purdue University, West Lafayette, IN 47907 (United States); Liang, Xinrong; Shan, Tizhong [Department of Animal Sciences, Purdue University, West Lafayette, IN 47907 (United States); Jiang, Qinyang [Department of Animal Sciences, Purdue University, West Lafayette, IN 47907 (United States); College of Animal Science and Technology, Guangxi University, Nanning 530004 (China); Deng, Changyan [Key Laboratory of Swine Genetics and Breeding of Agricultural Ministry & Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070 (China); Zheng, Rong, E-mail: zhengrong@mail.hzau.edu.cn [Key Laboratory of Swine Genetics and Breeding of Agricultural Ministry & Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070 (China); Kuang, Shihuan, E-mail: skuang@purdue.edu [Department of Animal Sciences, Purdue University, West Lafayette, IN 47907 (United States)

    2015-07-17

    The serine/threonine kinase mammalian target of rapamycin (mTOR) is a key regulator of protein synthesis, cell proliferation and energy metabolism. As constitutive deletion of Mtor gene results in embryonic lethality, the function of mTOR in muscle stem cells (satellite cells) and skeletal muscle regeneration remains to be determined. In this study, we established a satellite cell specific Mtor conditional knockout (cKO) mouse model by crossing Pax7{sup CreER} and Mtor{sup flox/flox} mice. Skeletal muscle regeneration after injury was severely compromised in the absence of Mtor, indicated by increased number of necrotic myofibers infiltrated by Evans blue dye, and reduced number and size of regenerated myofibers in the Mtor cKO mice compared to wild type (WT) littermates. To dissect the cellular mechanism, we analyzed satellite cell-derived primary myoblasts grown on single myofibers or adhered to culture plates. The Mtor cKO myoblasts exhibited defective proliferation and differentiation kinetics when compared to myoblasts derived from WT littermates. At the mRNA and protein levels, the Mtor cKO myoblasts expressed lower levels of key myogenic determinant genes Pax7, Myf5, Myod, Myog than did the WT myoblasts. These results suggest that mTOR is essential for satellite cell function and skeletal muscle regeneration through controlling the expression of myogenic genes. - Highlights: • Pax7{sup CreER} was used to delete Mtor gene in satellite cells. • Satellite cell specific deletion of Mtor impairs muscle regeneration. • mTOR is necessary for satellite cell proliferation and differentiation. • Deletion of Mtor leads to reduced expression of key myogenic genes.

  4. [Dynamics of terminal plaque structure during changes in the impulse activity of sensory endings in the process of their regeneration].

    Zamuraev, I N; Khonny, O A

    2002-01-01

    The dynamics of changes in terminal plates of frog's urinary bladder sensory free visceroceptors during their posttraumatic regeneration was studied. It was shown that during the time period from two months to one year the terminal plate number in receptor bush increased, while their average dimensions decreased and their shape changed. No correlations between the changes of afferent impulse activity and these morphological transformations were found. The data obtained suggest that terminal plates do not seem to participate in the generation of bioelectric activity, but rather appear to be the growth cones of non-myelinated terminal and thus are involved in repair processes. PMID:12108103

  5. Recent Activities in Magnetic Separation in Sweden

    Wang, Yanmin; Forssberg, Eric

    1995-01-01

    This paper describes some industrial applications of magnetic separation in Swedish mineral industry. Recent studies on magnetic treatment of minerals in Sweden are also presented. These studies involve selectivity of wet magnetic separation, wet magnetic recovery of mineral fines and ultrafines, sulphide processing by magnetic means, as well as dry magnetic purification of industrial minerals.

  6. Magnetic activity of planet-hosting stars

    Poppenhaeger, Katja

    2011-05-01

    Magnetic activity in cool stars is a widely observed phenomenon, however it is still far from being understood. How fundamental stellar parameters like mass and rotational period quantitatively cause a stellar magnetic field which manifests itself in features such as spots, flares and high-energy coronal emission is a lively area of research in solar and stellar astrophysics. Especially for planet-hosting stars, stellar activity profiles are very interesting as exoplanets are affected by high-energy radiation, both at the time of planet formation as well as during the further lifetime of a star-planet system. In extreme cases, the atmosphere of a planet very close to its host star can be strongly heated by the stellar X-ray and EUV emission and finally escape the planet's gravitational attraction, so that the atmosphere of the planet evaporates over time. Theoretically, planets can also affect their host star's magnetic activity. In analogy to processes in binary stars which lead to enhanced - both overall and periodically varying - activity levels, also giant planets might influence the stellar activity by tidal or magnetic interaction processes, however on a weaker level than in binaries. Some indications for such interactions exist from chromospheric measurements in stars with Hot Jupiters. In this thesis I investigate the magnetic activity of planet-hosting stars and especially possible effects from star-planet interactions with an emphasis on stellar coronae in X-rays. I tested a complete sample of all known planet-hosting stars within 30 pc distance from the Sun for correlations of stellar X-ray properties with planetary parameters. A significant correlation exists between the stellar X-ray luminosity and the product of planetary mass and inverse semimajor axis. However, this could be traced back to a selection effect introduced by planetary detection methods. For stars in the solar neighborhood, planets are mainly detected by radial velocity shifts in the

  7. Lack of robust satellite cell activation and muscle regeneration during the progression of Pompe disease

    Schaaf, Gerben J.; van Gestel, Tom JM; Brusse, Esther; Verdijk, Robert M.; de Coo, Irenaeus FM; Doorn Van, Pieter A; Ploeg, Ans T van der; Pijnappel, WWM Pim

    2015-01-01

    Introduction Muscle stem cells termed satellite cells are essential for muscle regeneration. A central question in many neuromuscular disorders is why satellite cells are unable to prevent progressive muscle wasting. We have analyzed muscle fiber pathology and the satellite cell response in Pompe disease, a metabolic myopathy caused by acid alpha-glucosidase deficiency and lysosomal glycogen accumulation. Pathology included muscle fiber vacuolization, loss of cross striation, and immune cell ...

  8. Magnetic activity in accretion disc boundary layers

    Armitage, Philip J.

    2002-03-01

    We use three-dimensional magnetohydrodynamic simulations to study the structure of the boundary layer between an accretion disc and a non-rotating, unmagnetized star. Under the assumption that cooling is efficient, we obtain a narrow but highly variable transition region in which the radial velocity is only a small fraction of the sound speed. A large fraction of the energy dissipation occurs in high-density gas adjacent to the hydrostatic stellar envelope, and may therefore be reprocessed and largely hidden from view of the observer. As suggested by Pringle, the magnetic field energy in the boundary layer is strongly amplified by shear, and exceeds that in the disc by an order of magnitude. These fields may play a role in generating the magnetic activity, X-ray emission and outflows in disc systems where the accretion rate is high enough to overwhelm the stellar magnetosphere.

  9. A study on the cementation of the regenerated cesium activity containing ferric, generated from elution of spent ion exchange resin

    For the studies on the cementation of the regenerated activity, 50 mL of 0.3 μCi Cs was taken with different strengths of ferric, viz. 0.5 N to 11 N,. The pH of the cement and ferric solutions of different strength was studied. Compressive strength studies of the cement blocks showed that at all strengths of ferric used for making the cement blocks, it was maximum at the 4th week and hence the curing time was fixed as 4 weeks

  10. Photospheric Magnetic Free Energy Density of Solar Active Regions

    Zhang, Hongqi

    2016-01-01

    We present the photospheric energy density of magnetic fields in two solar active regions inferred from observational vector magnetograms, and compare it with the possible different defined energy parameters of magnetic fields in the photosphere. We analyze the magnetic fields in active region NOAA 6580-6619-6659 and 11158. It is noticed that the quantity 1/4pi Bn.Bp is an important energy parameter that reflects the contribution of magnetic shear on the difference between the potential magnetic field (Bp) and non-potential one (Bn), and also the contribution to the free magnetic energy near the magnetic neutral lines in the active regions. It is found that the photospheric mean magnetic energy density changes obviously before the powerful solar flares in the active region NOAA 11158, it is consistent with the change of magnetic fields in the lower atmosphere with flares.

  11. ANTIOXIDANT ACTIVITY IN CALLUS CULTURES AND IN VITRO REGENERATED PLANTS OF ARTEMISIA NILAGIRICA (CLARKE PAMP.- AN IMPORTANT MEDICINAL PLANT SPECIES

    A. K. BALIARSINGH 1* , L. SAMANTA 2 AND S. S. MOHANTY 3

    2015-01-01

    dichlorophenoxyacetic  acid  (2,4-D  with  1.0  mg/L  Kinetin  (Kin  yielded maximum  callogenic  response.  Shoot  organogenesis  in  callus  cultures  was most favoured in MS containing 2.0 mg/L 6-benzylaminopurine (BAP and 0.5 mg/L indole-3-acetic acid (IAA. In vitro regenerated plantlets, emerged from culture medium, were acclimatized and the survival rate of ex vitro plants after soil transplantation  was 80-83% with  no apparent  phenotypic variations. The antioxidant  potential  of  natural  (in  vivo  plants,  callus  tissues  and  in  vitro regenerated plants before and after field transplantation (ex vitro plants were compared. DPPH scavenging activity was the highest in aqueous extracts of 10 week-old ex vitro plants than  other  sources.  Superoxide  anion  and  nitric  oxide  radical  scavenging  activity  was  the  highest  in ethanolic  extracts  of  10 week-old  ex  vitro  plants  where  as  the  hydroxyl  radical  was  the  maximum  in  6 week-old in vivo plants. Lipid peroxidation was neither observed in calli nor in regenerated plants of A. nilagirica.

  12. Towards the Design of 3D Fiber-Deposited Poly(ε-caprolactone)/lron-Doped Hydroxyapatite Nanocomposite Magnetic Scaffolds for Bone Regeneration.

    De Santis, Roberta; Russo, Alessandro; Gloria, Antonio; D'Amora, Ugo; Russo, Teresa; Panseri, Silvia; Sandri, Monica; Tampieri, Anna; Marcacci, Maurilio; Dediu, Valentin A; Wilde, Colin J; Ambrosio, Luigi

    2015-07-01

    In the past few years, researchers have focused on the design and development of three-dimensional (3D) advanced scaffolds, which offer significant advantages in terms of cell performance. The introduction of magnetic features into scaffold technology could offer innovative opportunities to control cell populations within 3D microenvironments, with the potential to enhance their use in tissue regeneration or in cell-based analysis. In the present study, 3D fully biodegradable and magnetic nanocomposite scaffolds for bone tissue engineering, consisting of a poly(ε-caprolactone) (PCL) matrix reinforced with iron-doped hydroxyapatite (FeHA) nanoparticles, were designed and manufactured using a rapid prototyping technique. The performances of these novel 3D PCL/FeHA scaffolds were assessed through a combination of theoretical evaluation, experimental in vitro analyses and in vivo testing in a rabbit animal model. The results from mechanical com- pression tests were consistent with FEM simulations. The in vitro results showed that the cell growth in the magnetized scaffolds was 2.2-fold greater than that in non-magnetized ones. In vivo experiments further suggested that, after only 4 weeks, the PCL/FeHA scaffolds were completely filled with newly formed bone, proving a good level of histocompatibility. All of the results suggest that the introduction of magnetic features into biocompatible materials may confer significant advantages in terms of 3D cell assembly. PMID:26307846

  13. Comparing superconducting and permanent magnets for magnetic refrigeration

    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...... regenerator and desiredinternal magnetic field. It is shown that to produce a 1 T internal field in theregenerator a permanent magnet of hundreds of kilograms is needed or an area ofsuperconducting tape of tens of square meters. The cost of cooling the SC solenoidis shown to be a small fraction of the cost of...... the SC tape. Assuming a cost ofthe SC tape of 6000 $/m2 and a price of the permanent magnet of 100 $/kg, thesuperconducting solenoid is shown to be a factor of 0.3-3 times more expensive thanthe permanent magnet, for a desired field from 0.5-1.75 T and the geometrical aspectratio of the regenerator...

  14. Brain-derived neurotrophic factor promotes nerve regeneration by activating the JAK/STAT pathway in Schwann cells

    Lin, Guiting; Zhang, Haiyang; Sun, Fionna; Lu, Zhihua; Reed-Maldonado, Amanda; Lee, Yung-Chin; Wang, Guifang; Banie, Lia

    2016-01-01

    Background Radical prostatectomy (RP) carries the risk of erectile dysfunction (ED) due to cavernous nerve (CN) injury. Schwann cells are essential for the maintenance of integrity and function of peripheral nerves such as the CNs. We hypothesize that brain-derived neurotrophic factor (BDNF) activates the Janus kinase (JAK)/(signal transducer and activator of transcription) STAT pathway in Schwann cells, not in neuronal axonal fibers, with the resultant secretion of cytokines from Schwann cells to facilitate nerve recovery. Methods Using four different cell lines—human neuroblastoma BE(2)-C and SH-SY5Y, human Schwann cell (HSC), and rat Schwann cell (RSC) RT4-D6P2T—we assessed the effect of BDNF application on the activation of the JAK/STAT pathway. We also assessed the time response of JAK/STAT pathway activation in RSCs and HSCs after BDNF treatment. We then assayed cytokine release from HSCs as a response to BDNF treatment using oncostatin M and IL6 as markers. Results We showed extensive phosphorylation of STAT3/STAT1 by BDNF at high dose (100 pM) in RSCs, with no JAK/STAT pathway activation in human neuroblastoma cell lines. The time response of JAK/STAT pathway activation in RSCs and HSCs after BDNF treatment showed an initial peak at shortly after treatment and then a second higher peak at 24–48 hours. Cytokine release from HSCs increased progressively after BDNF application, reaching statistical significance for IL6. Conclusions We demonstrated for the first time the indirect mechanism of BDNF enhancement of nerve regeneration through the activation of JAK/STAT pathway in Schwann cells, rather than directly on neurons. As a result of BDNF application, Schwann cells produce cytokines that promote nerve regeneration.

  15. Activation of mitochondrial glycerophosphate cytochrome c reductase in regenerating rat liver by triiodothyronine

    Lotková, H.; Rauchová, Hana; Drahota, Zdeněk

    2001-01-01

    Roč. 50, č. 3 (2001), s. 333-336. ISSN 0862-8408 R&D Projects: GA MŠk OC 918.50; GA ČR GA303/98/0473; GA ČR GA303/00/1658; GA MŠk LN00A069 Institutional research plan: CEZ:AV0Z5011922 Keywords : liver regeneration * triiodothyromine * glycerophosphate cytochrome c reductase Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 1.027, year: 2001

  16. Changing paradigms in cranio-facial regeneration: current and new strategies for the activation of endogenous stem cells

    Luigi eMele

    2016-02-01

    Full Text Available Craniofacial area represent a unique district of human body characterized by a very high complexity of tissues, innervation and vascularization, and being deputed to many fundamental function such as eating, speech, expression of emotions, delivery of sensations such as taste, sight and earing. For this reasons, tissue loss in this area following trauma or for example oncologic resection, have a tremendous impact on patients’ quality of life. In the last 20 years regenerative medicine has emerged as one of the most promising approach to solve problem related to trauma, tissue loss, organ failure etc. One of the most powerful tools to be used for tissue regeneration is represented by stem cells, which have been successfully implanted in different tissue/organs with exciting results. Nevertheless both autologous and allogeneic stem cell transplantation raise many practical and ethical concerns that make this approach very difficult to apply in clinical practice. For this reason different cell free approaches have been developed aiming to the mobilization, recruitment and activation of endogenous stem cells into the injury site avoiding exogenous cells implant but instead stimulating patients’ own stem cells to repair the lesion. To this aim many strategies have been used including functionalized bioscaffold, controlled release of stem cell chemoattractants, growth factors, BMPs, Platelet–Rich-Plasma and other new strategies such as ultrasound wave and laser are just being proposed. Here we review all the current and new strategies used for activation and mobilization of endogenous stem cells in the regeneration of craniofacial tissue.

  17. Changing Paradigms in Cranio-Facial Regeneration: Current and New Strategies for the Activation of Endogenous Stem Cells.

    Mele, Luigi; Vitiello, Pietro Paolo; Tirino, Virginia; Paino, Francesca; De Rosa, Alfredo; Liccardo, Davide; Papaccio, Gianpaolo; Desiderio, Vincenzo

    2016-01-01

    Craniofacial area represent a unique district of human body characterized by a very high complexity of tissues, innervation and vascularization, and being deputed to many fundamental function such as eating, speech, expression of emotions, delivery of sensations such as taste, sight, and earing. For this reasons, tissue loss in this area following trauma or for example oncologic resection, have a tremendous impact on patients' quality of life. In the last 20 years regenerative medicine has emerged as one of the most promising approach to solve problem related to trauma, tissue loss, organ failure etc. One of the most powerful tools to be used for tissue regeneration is represented by stem cells, which have been successfully implanted in different tissue/organs with exciting results. Nevertheless, both autologous and allogeneic stem cell transplantation raise many practical and ethical concerns that make this approach very difficult to apply in clinical practice. For this reason different cell free approaches have been developed aiming to the mobilization, recruitment, and activation of endogenous stem cells into the injury site avoiding exogenous cells implant but instead stimulating patients' own stem cells to repair the lesion. To this aim many strategies have been used including functionalized bioscaffold, controlled release of stem cell chemoattractants, growth factors, BMPs, Platelet-Rich-Plasma, and other new strategies such as ultrasound wave and laser are just being proposed. Here we review all the current and new strategies used for activation and mobilization of endogenous stem cells in the regeneration of craniofacial tissue. PMID:26941656

  18. Cardiac regeneration by pharmacologically active microcarriers releasing growth factors and/or transporting adipose-derived stem cells

    Monia Savi

    2014-01-01

    Full Text Available We tested the hypothesis that cardiac regeneration through local delivery of adipose-derived stem cells (ASCs, activation of resident cardiac stem cells via growth factors (GFs [hepatocyte growth factor (HGF and insulin-like growth factor 1 (IGF-1:GFs] or both, are improved by pharmacologically active microcarriers (PAMs interacting with cells/molecules conveyed on their surface. Rats with one-month old myocardial infarction were treated with ASCs, ASCs+PAMs, GF-releasing PAMs, ASCs+GF-releasing PAMs or vehicle. Two weeks later, hemodynamic function and inducibility of ventricular arrhythmias (VAs were assessed. Eventually, the hearts were subjected to anatomical and immunohistochemical analyses. A significant ASCs engraftment and the largest improvement in cardiac mechanics occurred in ASC+GF-releasing PAM rats which by contrast were more vulnerable to VAs. Thus, PAMs may improve cell/GF-based cardiac regeneration although caution should be paid on the electrophysiological impact of their physical interaction with the myocardium.

  19. Changing Paradigms in Cranio-Facial Regeneration: Current and New Strategies for the Activation of Endogenous Stem Cells

    Mele, Luigi; Vitiello, Pietro Paolo; Tirino, Virginia; Paino, Francesca; De Rosa, Alfredo; Liccardo, Davide; Papaccio, Gianpaolo; Desiderio, Vincenzo

    2016-01-01

    Craniofacial area represent a unique district of human body characterized by a very high complexity of tissues, innervation and vascularization, and being deputed to many fundamental function such as eating, speech, expression of emotions, delivery of sensations such as taste, sight, and earing. For this reasons, tissue loss in this area following trauma or for example oncologic resection, have a tremendous impact on patients' quality of life. In the last 20 years regenerative medicine has emerged as one of the most promising approach to solve problem related to trauma, tissue loss, organ failure etc. One of the most powerful tools to be used for tissue regeneration is represented by stem cells, which have been successfully implanted in different tissue/organs with exciting results. Nevertheless, both autologous and allogeneic stem cell transplantation raise many practical and ethical concerns that make this approach very difficult to apply in clinical practice. For this reason different cell free approaches have been developed aiming to the mobilization, recruitment, and activation of endogenous stem cells into the injury site avoiding exogenous cells implant but instead stimulating patients' own stem cells to repair the lesion. To this aim many strategies have been used including functionalized bioscaffold, controlled release of stem cell chemoattractants, growth factors, BMPs, Platelet–Rich-Plasma, and other new strategies such as ultrasound wave and laser are just being proposed. Here we review all the current and new strategies used for activation and mobilization of endogenous stem cells in the regeneration of craniofacial tissue. PMID:26941656

  20. Live in vivo imaging of Egr-1 promoter activity during neonatal development, liver regeneration and wound healing

    Schaper Wolfgang

    2011-05-01

    Full Text Available Abstract Background The zinc finger transcription factor Egr-1 (Early growth response 1 is central to several growth factors and represents an important activator of target genes not only involved in physiological processes like embryogenesis and neonatal development, but also in a variety of pathophysiological processes, for example atherosclerosis or cancer. Current options to investigate its transcription and activation in vivo are end-point measurements that do not provide insights into dynamic changes in the living organism. Results We developed a transgenic mouse (Egr-1-luc in which the luciferase reporter gene is under the control of the murine Egr-1 promoter providing a versatile tool to study the time course of Egr-1 activation in vivo. In neonatal mice, bioluminescence imaging revealed a high Egr-1 promoter activity reaching basal levels three weeks after birth with activity at snout, ears and paws. Using a model of partial hepatectomy we could show that Egr-1 promoter activity and Egr-1 mRNA levels were increased in the regenerating liver. In a model of wound healing, we demonstrated that Egr-1 promoter activity was upregulated at the site of injury. Conclusion Taken together, we have developed a transgenic mouse model that allows real time in vivo imaging of the Egr-1 promoter activity. The ability to monitor and quantify Egr-1 activity in the living organism may facilitate a better understanding of Egr-1 function in vivo.

  1. Activity estimation in radioimmunotherapy using magnetic nanoparticles

    Rajabi, Hossein; Johari Daha, Fariba

    2015-01-01

    Objective Estimation of activity accumulated in tumor and organs is very important in predicting the response of radiopharmaceuticals treatment. In this study, we synthesized 177Lutetium (177Lu)-trastuzumab-iron oxide nanoparticles as a double radiopharmaceutical agent for treatment and better estimation of organ activity in a new way by magnetic resonance imaging (MRI). Methods 177Lu-trastuzumab-iron oxide nanoparticles were synthesized and all the quality control tests such as labeling yield, nanoparticle size determination, stability in buffer and blood serum up to 4 d, immunoreactivity and biodistribution in normal mice were determined. In mice bearing breast tumor, liver and tumor activities were calculated with three methods: single photon emission computed tomography (SPECT), MRI and organ extraction, which were compared with each other. Results The good results of quality control tests (labeling yield: 61%±2%, mean nanoparticle hydrodynamic size: 41±15 nm, stability in buffer: 86%±5%, stability in blood serum: 80%±3%, immunoreactivity: 80%±2%) indicated that 177Lu-trastuzumab-iron oxide nanoparticles could be used as a double radiopharmaceutical agent in mice bearing tumor. Results showed that 177Lu-trastuzumab-iron oxide nanoparticles with MRI had the ability to measure organ activities more accurate than SPECT. Conclusions Co-conjugating radiopharmaceutical to MRI contrast agents such as iron oxide nanoparticles may be a good way for better dosimetry in nuclear medicine treatment. PMID:25937783

  2. Deciphering Solar Magnetic Activity: On Grand Minima in Solar Activity

    McIntosh, Scott W

    2015-01-01

    The Sun provides the energy necessary to sustain our existence. While the Sun provides for us, it is also capable of taking away. The weather and climatic scales of solar evolution and the Sun-Earth connection are not well understood. There has been tremendous progress in the century since the discovery of solar magnetism - magnetism that ultimately drives the electromagnetic, particulate and eruptive forcing of our planetary system. There is contemporary evidence of a decrease in solar magnetism, perhaps even indicators of a significant downward trend, over recent decades. Are we entering a minimum in solar activity that is deeper and longer than a typical solar minimum, a "grand minimum"? How could we tell if we are? What is a grand minimum and how does the Sun recover? These are very pertinent questions for modern civilization. In this paper we present a hypothetical demonstration of entry and exit from grand minimum conditions based on a recent analysis of solar features over the past 20 years and their p...

  3. A Model of Mercury's Magnetospheric Magnetic Field with Dependence on Magnetic Activity

    Korth, H.; Tsyganenko, N. A.; Johnson, C. L.; Philpott, L. C.; Anderson, B. J.; Solomon, S. C.; McNutt, R. L., Jr.

    2015-12-01

    Accurate knowledge of Mercury's magnetospheric magnetic field is required to characterize the planet's internal field and the structure of the magnetosphere. We present the first model of Mercury's magnetospheric magnetic field that includes a dependence on magnetic activity. The model consists of individual modules for magnetic fields of internal origin, approximated by a dipole of magnitude 190 nT RM3, where RM is Mercury's radius, offset northward by 479 km along the spin axis, and of external origin resulting from currents flowing on the magnetopause boundary and in the cross-tail current sheet. The magnetic field is confined within a magnetopause shape derived from Magnetometer observations by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft and dependent on magnetic activity. The cross-tail current is prescribed having a disk shape near the planet and extending into a sheet at larger distances. The magnitude of the tail current, which also depends on magnetic activity, is fit to minimize the root-mean-square residual between the model magnetic field and the field within the magnetosphere observed by MESSENGER. The model was fit separately for magnetic field observations within distinct levels of magnetic activity. Linear fits of model parameters versus magnetic activity allows continuous scaling of the model to magnetic activity. The magnetic field contribution from each module is shielded individually by a scalar potential function, which was fit to minimize the root-mean-square normal magnetic field component at the magnetopause. The resulting model reproduces the dependence of the magnetospheric size and tail current intensity on magnetic activity, and allows more accurate characterization of the internal field.

  4. Quantitative magnetic resonance imaging as marker of synovial membrane regeneration and recurrence of synovitis after arthroscopic knee joint synovectomy: a one year follow up study

    Østergaard, Mikkel; Ejbjerg, B; Stoltenberg, M; Gideon, P; Volck, B; Skov, K; Jensen, Claus Hjorth; Lorenzen, I

    2001-01-01

    OBJECTIVES: By repeated magnetic resonance imaging (MRI) to study synovial membrane regeneration and recurrence of synovitis after arthroscopic knee joint synovectomy in patients with rheumatoid arthritis (RA) and other (non-RA) causes of persistent knee joint synovitis. METHODS: Contrast enhanced...... MRI was performed in 15 knees (nine RA, six non-RA) before and one day, seven days, two months, and 12 months after arthroscopic synovectomy. Synovial membrane volumes, joint effusion volumes, and cartilage and bone destruction were assessed on each MRI set. Baseline microscopic and macroscopic...... assessments of synovitis and baseline and follow up standard clinical and biochemical examinations were available. RESULTS: Synovial membrane and joint fluid volumes were significantly reduced two and 12 months after synovectomy. However, MRI signs of recurrent synovitis were already present in most knees at...

  5. Comparisons of kinetics, thermodynamics and regeneration of tetramethylammonium hydroxide adsorption in aqueous solution with graphene oxide, zeolite and activated carbon

    Chang, Shenteng; Lu, Chungsying; Lin, Kun-Yi Andrew

    2015-01-01

    Graphene oxide (GO), sodium Y-type zeolite (NaY) and granular activated carbon (GAC) are selected as adsorbents to study their kinetics, thermodynamics and regeneration of tetramethylammonium hydroxide (TMAH) adsorption from water. The adsorption kinetics follows the pseudo-second-order rate law while the adsorption thermodynamics shows an exothermic reaction with GO and GAC but displays an endothermic reaction with NaY. The adsorbed TMAH can be readily desorbed from the surface of GO and NaY by 0.05 M NaCl solution. A comparative study on the cyclic TMAH adsorption with GO, NaY and GAC is also conducted and the results reveal that GO exhibits the greatest TMAH adsorption capacity as well as superior reversibility of TMAH adsorption over 10 cycles of adsorption and desorption process. These features indicate that GO is a promising and efficient adsorbent for TMAH removal in wastewater treatment.

  6. An active antenna for ELF magnetic fields

    Sutton, John F.; Spaniol, Craig

    1994-01-01

    The work of Nikola Tesla, especially that directed toward world-wide electrical energy distribution via excitation of the earth-ionosphere cavity resonances, has stimulated interest in the study of these resonances. Not only are they important for their potential use in the transmission of intelligence and electrical power, they are important because they are an integral part of our natural environment. This paper describes the design of a sensitive, untuned, low noise active antenna which is uniquely suited to modern earth-ionosphere cavity resonance measurements employing fast-Fourier transform techniques for near-real-time data analysis. It capitalizes on a little known field-antenna interaction mechanism. Recently, the authors made preliminary measurements of the magnetic fields in the earth-ionosphere cavity. During the course of this study, the problem of designing an optimized ELF magnetic field sensor presented itself. The sensor would have to be small, light weight (for portable use), and capable of detecting the 5-50 Hz picoTesla-level signals generated by the natural excitations of the earth-ionosphere cavity resonances. A review of the literature revealed that past researchers had employed very large search coils, both tuned and untuned. Hill and Bostick, for example, used coils of 30,000 turns wound on high permeability cores of 1.83 m length, weighing 40 kg. Tuned coils are unsuitable for modern fast-Fourier transform data analysis techniques which require a broad spectrum input. 'Untuned' coils connected to high input impedance voltage amplifiers exhibit resonant responses at the resonant frequency determined by the coil inductance and the coil distributed winding capacitance. Also, considered as antennas, they have effective areas equal only to their geometrical areas.

  7. Magnetic activity at Mars - Mars Surface Magnetic Observatory

    Vennerstrøm, Susanne; Menvielle, M.; Merayo, José M.G.;

    2012-01-01

    , and use this to provide an estimate of the expected magnetic disturbances at the Martian surface. Far from crustal anomaly regions the expected magnetic disturbances originating from currents associated with the induced magnetosphere are very weak at the day-side, but most likely larger on the night...... around medium intensity radial anomalies in the equatorial region appear to derive from local current loops or vortices around cusp-like radial fields, acting to partly cancel the crustal field. The radial perturbation is further found to depend on upstream solar wind dynamic pressure. We define a...

  8. Pulse-driven magnetoimpedance sensor detection of cardiac magnetic activity.

    Shinsuke Nakayama

    Full Text Available This study sought to establish a convenient method for detecting biomagnetic activity in the heart. Electrical activity of the heart simultaneously induces a magnetic field. Detection of this magnetic activity will enable non-contact, noninvasive evaluation to be made. We improved the sensitivity of a pulse-driven magnetoimpedance (PMI sensor, which is used as an electric compass in mobile phones and as a motion sensor of the operation handle in computer games, toward a pico-Tesla (pT level, and measured magnetic fields on the surface of the thoracic wall in humans. The changes in magnetic field detected by this sensor synchronized with the electric activity of the electrocardiogram (ECG. The shape of the magnetic wave was largely altered by shifting the sensor position within 20 mm in parallel and/or perpendicular to the thoracic wall. The magnetic activity was maximal in the 4th intercostals near the center of the sterna. Furthermore, averaging the magnetic activity at 15 mm in the distance between the thoracic wall and the sensor demonstrated magnetic waves mimicking the P wave and QRS complex. The present study shows the application of PMI sensor in detecting cardiac magnetic activity in several healthy subjects, and suggests future applications of this technology in medicine and biology.

  9. Self–activation and effect of regeneration conditions in CO2 – carbonate looping with CaO - Ca12Al14O33 sorbent

    STENDARDO Stefano; Andersen, Lars; HERCE C

    2012-01-01

    CO2 capture by solid sorbents through uptake–regeneration cycling is a promising option for high temperature removal of CO2 from combustion gases and synthesis/fuel gases. The present study investigates the influence of regeneration atmosphere and temperature on the CO2 uptake capacity during repeated cycling of CaO–based solid sorbents. The sorbents were synthesised to contain 75 and 85 %w/w of active phase (CaO) and binder (Ca12Al14O33) and were then subjected to cycling tests with repeate...

  10. 40-Gb/s all-optical wavelength conversion, regeneration, and demultiplexing in an SOA-based all-active Mach-Zehnder interferometer

    Wolfson, David; Kloch, Allan; Fjelde, Tina;

    2000-01-01

    All-optical 2R and 3R regeneration techniques are investigated at 40 Gb/s, It is shown that an all-active SOA-based Mach-Zehnder device, employed as a,wavelength converter, is capable of improving the OSNR by more than 20 dB at this bit rate, thereby resulting in penalty reduction. Furthermore......, simultaneous all-optical wavelength conversion and demultiplexing from 40 to 10 Gb/s is demonstrated showing that the scheme, which also has a 3R regeneration capability, is feasible in a combined OTDM/WDM network....

  11. Chloroplast ultra structure, photosynthesis and enzyme activities in regenerated plants of Stevia rebaudiana (Bert.) Bertoni as influenced by copper sulphate in the medium.

    Jain, Pourvi; Kachhwaha, Sumita; Kothari, S L

    2014-09-01

    Stevia rebaudiana (Bert.) Bertoni is an important medicinal plant used as noncaloric commercial sweetener. Plants regenerated with higher levels of copper sulphate in the medium exhibited enhanced activity of peroxidase and polyphenoloxidase (PPO) enzymes. Transmission electron microscopy (TEM) revealed increase in size and number of electron dense inclusions in the chloroplasts of plants regenerated at optimised level of copper sulphate (0.5 microM) in the medium. There was decrease in chlorogenic acid (CGA) content. Chl-a-fluorescence transient pattern (OJIP) showed that the photosynthesis process was more efficient at 0.5 microM CuSO4 in the medium. PMID:25241590

  12. Study on the regeneration of activated carbon with microwave technology from sewage sludge%微波技术再生污泥活性炭的研究

    吕春芳; 高盼盼

    2013-01-01

    Methylene blue was employed as a pollutant to contaminate activated carbon filters and then microwave irradiation was used for regeneration of the activated carbon.The relationship between regeneration performance for saturated activated carbon and concentration of assisted solvent,pH,microwave power,time of microwave radiation,AC quantity,and other factors were discussed.The results showed that the optimized conditions of regeneration were as follows:the microwave power is 650 W for 120 s and the quantity of AC is 3 g,activated carbon regeneration capability under the optimum condition is closed to 100%,even more than 100%.%以亚甲基蓝为污染物污染活性炭,利用微波辐照的方法对失效的活性炭进行再生.探讨了污泥活性炭的再生性能与辅助溶液的浓度、pH、微波功率、辐照时间、活性炭的用量等因素的关系.结果表明,微波法再生活性炭的最佳条件为:微波功率650 W,辐照时间120 s,辐照活性炭质量3 g.此时,其性能恢复率接近100%,甚至超过100%.

  13. Applications of magnetically active fibre reinforced composites

    Etches, Julie; Bond, Ian; Mellor, Philip

    2005-05-01

    As the application of fibre reinforced polymer composites (FRP) becomes more widespread there is a desire to add functionality beyond that of simple mechanical properties in order to facilitate the development of 'smart' materials. For example, the functionality being discussed in this paper is the imparting of significant magnetic properties to a FRP. This can take the form of soft magnetic performance for use in electrical machines or hard magnetic performance for novel forms of sensing or power generation. It has been demonstrated that by using hollow glass fibres as a reinforcement, magnetic material can be introduced into these fibres without significant effects on the structural behaviour of the FRP. The current studies have included the assessment of such a magnetic FRP in a variety of applications. The addition of hard magnetic materials, e.g. magnetite and barium ferrite, has been achieved through the use of nanopowders and the resulting FRP has been assessed for morphing structures applications. The magnitude of magnetic performance that can be currently achieved is controlled by the availability of suitable magnetic materials in fine powder form and the volume of magnetic material which can be incorporated within the fibres.

  14. Magnetic activity of surface plasmon resonance using dielectric magnetic materials fabricated on quartz glass substrate

    Narushima, Kazuki; Ashizawa, Yoshito; Brachwitz, Kerstin; Hochmuth, Holger; Lorenz, Michael; Grundmann, Marius; Nakagawa, Katsuji

    2016-07-01

    The magnetic activity of surface plasmons in Au/MFe2O4 (M = Ni, Co, and Zn) polycrystalline bilayer films fabricated on a quartz glass substrate was studied for future magnetic sensor applications using surface plasmon resonance. The excitation of surface plasmons and their magnetic activity were observed in all investigated Au/MFe2O4 films. The magnetic activity of surface plasmons of the polycrystalline Au/NiFe2O4 film was larger than those of the other polycrystalline Au/MFe2O4 films, the epitaxial NiFe2O4 film, and metallic films. The large magnetic activity of surface plasmons of the polycrystalline film is controlled by manipulating surface plasmon excitation conditions and magnetic properties.

  15. A magnetically active microfluidic device for chemiluminescence bioassays

    Zheng, Yi; Zhao, Shulin; Liu, Yi-Ming

    2011-01-01

    Highly active horseradish peroxidase functionalized magnetic nanoparticles were prepared and packed into a microfluidic channel, producing an in-line bioreactor that enabled a sensitive chemiluminescence assay of H2O2. The proposed magnetically active microfluidic device proved useful for chemiluminescence assays of biomedically interesting compounds.

  16. Active screening of magnetic field near power stations generator buses

    B.I. Kuznetsov

    2013-12-01

    Full Text Available An experimental study technique for a prototyping system of active screening of power-frequency magnetic field distortions near power station generator buses via controllable magnetic field sources is presented. Results of experimental research on a proto-typing active screening system with different control algorithms are given.

  17. Microgravity can activate signals urging cells to S-phase entry during tissue and organ regeneration in Urodele amphibians exposed to real and simulated microgravity

    Grigoryan, E.; Anton, H.-J.; Mitashov, V.

    Regenerative response following local injury or tissue removal in urodele amphibians is dependent on cell cycle entry of cells sources for regeneration in the remaining tissue. In a number of our experiments performed aboard biosatellites in orbital flights and fast rotated clinostat we found enhanced proliferative activity and, as a result, regeneration quicker than that in controls. In each investigated case an activity of cell proliferation evaluated by 3H-thymidine radioautography and BrdU assay at the early stages of lens, retina, forelimb and tail regeneration in newts was about 1,2-1,7 fold higher both under conditions of real and physiological weightlessness as compared with controls. Faster S-phase entry under conditions of micro- g was demonstrated by cycling multipotent cells as well as by differentiated postmitotic cells both participated in regeneration. Important, that cycling cells outside areas of regeneration were also found as displayed faster cellular growth. In our papers (1,2,3,4) we offered some hypothesis that could explain mechanisms of low g stimulating effect upon cell growth in regeneration in Urodela. In particular, changes in expression of some growth factors and their receptors, as well as the synthesis of specific range of generalized stress proteins (AGSPs) were proposed. However, in fact, molecular mechanisms of micro- g effect upon cell proliferation are mediated by changes on organismic level induced by micro- g environment. Some of them which are able to trigger off signaling changes on the cellular level that, in turn, evoke cells to grow faster would be represented in our report. 1. Mitashov V. et al. Adv. Space Res. 1996. 17 (6/7): 241-255 2. Anton H.-J. et al. Adv. Space Res. 1996. 17 (6/7): 55-65 3. Grigoryan E. et al. Adv. Space Res. 1998. 22 (2): 293-301 4. Grigoryan E. et al. Adv. Space Res. 2002. 30 (4): 757-764

  18. Magnetic history of solar active regions

    An attempt was made to use recent magnetic observations to trace the history of a typical solar active region from birth to death. By comparing the short-term motions to the long-term spreading, it is demonstrated that the decay process is dominated, over periods ranging from days to months, by a random walk of field lines, with a diffusion constant of roughly 200 to 400 km2/sec. While the interaction between diffusion and differential rotation dictates the geometric pattern of the decaying region, the actual quantity of surviving flux appears to be less, and its ultimate annihilation more thorough, than would have been expected. This probably indicates a continued subsurface coupling between opposite polarity features. In addition, the long-range agreement between theory and observation is considerably improved by postulating the existence, in the middle latitudes of each hemisphere, of a systematic, poleward-moving meridional flow of about 3 m/sec. The outlook for being able to make continued progress towards the understanding of basic solar phenomena by further efforts in this direction is promising

  19. MAGNET

    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...

  20. Designing a magnet for magnetic refrigeration

    Bjørk, Rasmus

    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...

  1. Understanding Urban Regeneration in Turkey

    Candas, E.; Flacke, J.; Yomralioglu, T.

    2016-06-01

    In Turkey, rapid population growth, informal settlements, and buildings and infrastructures vulnerable to natural hazards are seen as the most important problems of cities. Particularly disaster risk cannot be disregarded, as large parts of various cities are facing risks from earthquakes, floods and landslides and have experienced loss of lives in the recent past. Urban regeneration is an important planning tool implemented by local and central governments in order to reduce to disaster risk and to design livable environments for the citizens. The Law on the Regeneration of Areas under Disaster Risk, commonly known as the Urban Regeneration Law, was enacted in 2012 (Law No.6306, May 2012). The regulation on Implementation of Law No. 6306 explains the fundamental steps of the urban regeneration process. The relevant institutions furnished with various authorities such as expropriation, confiscation and changing the type and place of your property which makes urban regeneration projects very important in terms of property rights. Therefore, urban regeneration projects have to be transparent, comprehensible and acceptable for all actors in the projects. In order to understand the urban regeneration process, the legislation and projects of different municipalities in Istanbul have been analyzed. While some steps of it are spatial data demanding, others relate to land values. In this paper an overview of the urban regeneration history and activities in Turkey is given. Fundamental steps of the urban regeneration process are defined, and particularly spatial-data demanding steps are identified.

  2. Seed recovery and regeneration

    Magnetohydrodynamic's (MHD) electric power generation capability depends on Faraday's law of induction. An ionized gas, called plasma, passes through a fixed magnetic field. The plasma is produced by seeding flue gases at a temperature of around 2500 deg C with potassium carbonate or formate. In a coal-fired open cycle MHD power plant the potassium seed material is in direct contact with the polluted flue gas from coal combustion. The molten slag droplets will capture a certain amount of potassium. The sulphur dioxide in the flue gases will react with potassium to potassium sulphate. The spent seed material has to be recovered and reprocessed so that the potassium can be reused as seed material. We can distinguish a preprocessing and a regeneration step. Seed preprocessing removes the minerals and volatile coal constituents from the potassium salts. Seed regeneration transforms the purified potassium sulphate into potassium carbonate or formate. Eight regeneration processes have been evaluated. The processes that convert the sulphur of the coal into saleable sulphur or sulphuric acid are still at an early stage of development. Considering all pros and cons, the Formate/Econoseed process appears most suited for seed regeneration purposes in coal-fired MHD systems. For an advanced MHD power plant the mass flow rates of the flue gas and of the potassium containing off-product streams will be calculated. It will be shown that the sulphur content of coal will influence the economical efficiency of the power plant

  3. The Limit of Free Magnetic Energy in Active Regions

    Moore, Ron; Falconer, David; Sterling, Alphonse

    2012-01-01

    By measuring from active-region magnetograms a proxy of the free energy in the active region fs magnetic field, it has been found previously that (1) there is an abrupt upper limit to the free energy the field can hold that increases with the amount of magnetic field in the active region, the active region fs magnetic flux content, and (2) the free energy is usually near its limit when the field explodes in a CME/flare eruption. That is, explosive active regions are concentrated in a main-sequence path bordering the free-energy ]limit line in (flux content, free-energy proxy) phase space. Here, from measurement of Marshall Space Flight Center vector magnetograms, we find the magnetic condition that underlies the free ]energy limit and the accompanying main sequence of explosive active regions. Using a suitable free ]energy proxy measured from vector magnetograms of 44 active regions, we find that (1) in active regions at and near their free ]energy limit, the ratio of magnetic-shear free energy to the non ]free magnetic energy the potential field would have is approximately 1 in the core field, the field rooted along the neutral line, and (2) this ratio is progressively less in active regions progressively farther below their free ]energy limit. This shows that most active regions in which this core-field energy ratio is much less than 1 cannot be triggered to explode; as this ratio approaches 1, most active regions become capable of exploding; and when this ratio is 1 or greater, most active regions are compelled to explode. From these results we surmise the magnetic condition that determines the free ]energy limit is the ratio of the free magnetic energy to the non-free energy the active region fs field would have were it completely relaxed to its potential ]field configuration, and that this ratio is approximately 1 at the free-energy limit and in the main sequence of explosive active regions.

  4. All optical regeneration using semiconductor devices

    Mørk, Jesper; Öhman, Filip; Tromborg, Bjarne

    All-optical regeneration is a key functionality for implementing all-optical networks. We present a simple theory for the bit-error-rate in links employing all-optical regenerators, which elucidates the interplay between the noise and and nonlinearity of the regenerator. A novel device structure ...... analyzed, emphasizing general aspects of active semiconductor waveguides....

  5. Light-Activated Magnetic Compass in Birds

    Solov'yov, Ilia; Greiner, Walter

    2013-01-01

    Migrating birds fly thousand miles without having a map, or a GPS unit. But they may carry their own sensitive navigational tool, which allows them "see" the Earth’s magnetic field. Here we review the important physical and chemical constraints on a possible compass sensor and discuss the suggest......Migrating birds fly thousand miles without having a map, or a GPS unit. But they may carry their own sensitive navigational tool, which allows them "see" the Earth’s magnetic field. Here we review the important physical and chemical constraints on a possible compass sensor and discuss...... the suggestion that radical pairs in a photoreceptor cryptochrome might provide a biological realization for a magnetic compass. Finally, we review the current evidence supporting a role for radical pair reactions in the magnetic compass of birds....

  6. Evaluating the effect of magnetocaloric properties on magnetic refrigeration performance

    Engelbrecht, Kurt; Bahl, Christian Robert Haffenden

    2010-01-01

    Active magnetic regenerator (AMR) refrigerators represent an alternative to vapor compression technology that relies on the magnetocaloric effect in a solid refrigerant. Magnetocaloric materials are in development and properties are reported regularly. Recently, there has been an emphasis on...

  7. Pulse-Driven Magnetoimpedance Sensor Detection of Cardiac Magnetic Activity

    Nakayama, Shinsuke; Sawamura, Kenta; Mohri, Kaneo; Uchiyama, Tsuyoshi

    2011-01-01

    This study sought to establish a convenient method for detecting biomagnetic activity in the heart. Electrical activity of the heart simultaneously induces a magnetic field. Detection of this magnetic activity will enable non-contact, noninvasive evaluation to be made. We improved the sensitivity of a pulse-driven magnetoimpedance (PMI) sensor, which is used as an electric compass in mobile phones and as a motion sensor of the operation handle in computer games, toward a pico-Tesla (pT) level...

  8. Modulation of ornithine decarboxylase activity in the normal and regenerating rat liver by various doses of the peptide morphogen of Hydra

    In this investigation, changes in ornithine decarboxylase (ODC) activity were studied in the normal and regenerating liver of rats receiving injections of various doses of Hydra peptide morphogen (HPM). Activity of ODC was determined by a radioisotope method based on liberation of 14CO2 from L-(1-14C)-ornithine. The results indicate in the author's opinion that HPM may have a role in the regulation of anabolic processes and, in particular, of regenerative processes in mammals

  9. Site-Specific Bioconjugation of an Organometallic Electron Mediator to an Enzyme with Retained Photocatalytic Cofactor Regenerating Capacity and Enzymatic Activity

    Sung In Lim

    2015-04-01

    Full Text Available Photosynthesis consists of a series of reactions catalyzed by redox enzymes to synthesize carbohydrates using solar energy. In order to take the advantage of solar energy, many researchers have investigated artificial photosynthesis systems mimicking the natural photosynthetic enzymatic redox reactions. These redox reactions usually require cofactors, which due to their high cost become a key issue when constructing an artificial photosynthesis system. Combining a photosensitizer and an Rh-based electron mediator (RhM has been shown to photocatalytically regenerate cofactors. However, maintaining the high concentration of cofactors available for efficient enzymatic reactions requires a high concentration of the expensive RhM; making this process cost prohibitive. We hypothesized that conjugation of an electron mediator to a redox enzyme will reduce the amount of electron mediators necessary for efficient enzymatic reactions. This is due to photocatalytically regenerated NAD(PH being readily available to a redox enzyme, when the local NAD(PH concentration near the enzyme becomes higher. However, conventional random conjugation of RhM to a redox enzyme will likely lead to a substantial loss of cofactor regenerating capacity and enzymatic activity. In order to avoid this issue, we investigated whether bioconjugation of RhM to a permissive site of a redox enzyme retains cofactor regenerating capacity and enzymatic activity. As a model system, a RhM was conjugated to a redox enzyme, formate dehydrogenase obtained from Thiobacillus sp. KNK65MA (TsFDH. A RhM-containing azide group was site-specifically conjugated to p-azidophenylalanine introduced to a permissive site of TsFDH via a bioorthogonal strain-promoted azide-alkyne cycloaddition and an appropriate linker. The TsFDH-RhM conjugate exhibited retained cofactor regenerating capacity and enzymatic activity.

  10. A comprehensive parameter study of an active magnetic regenerator using a 2D numerical model

    Nielsen, Kaspar Kirstein; Bahl, Christian Robert Haffenden; Smith, Anders;

    2010-01-01

    , cycle frequency and fluid movement. These are cast into the non-dimensional units utilization, porosity and number of transfer units (NTU). The cooling capacity vs. temperature span is mapped as a function of these parameters and each configuration is evaluated through the maximum temperature span and...

  11. Magnetically Responsive Activated Carbons for Bio - and Environmental Applications

    Šafařík, Ivo; Horská, Kateřina; Popisková, K.; Šafaříková, Miroslava

    2012-01-01

    Roč. 4, č. 3 (2012), s. 346-352. ISSN 2035-1755 R&D Projects: GA ČR(CZ) GAP503/11/2263; GA MŠk LH12190 Institutional support: RVO:67179843 Keywords : Activated Carbon * Magnetic Modification * Magnetic Separation Subject RIV: EH - Ecology, Behaviour

  12. The Basis of Muscle Regeneration

    Antonio Musarò

    2014-01-01

    Full Text Available Muscle regeneration recapitulates many aspects of embryonic myogenesis and is an important homeostatic process of the adult skeletal muscle, which, after development, retains the capacity to regenerate in response to appropriate stimuli, activating the muscle compartment of stem cells, namely, satellite cells, as well as other precursor cells. Moreover, significant evidence suggests that while stem cells represent an important determinant for tissue regeneration, a “qualified” environment is necessary to guarantee and achieve functional results. It is therefore plausible that the loss of control over these cell fate decisions could lead to a pathological transdifferentiation, leading to pathologic defects in the regenerative process. This review provides an overview about the general aspects of muscle development and discusses the cellular and molecular aspects that characterize the five interrelated and time-dependent phases of muscle regeneration, namely, degeneration, inflammation, regeneration, remodeling, and maturation/functional repair.

  13. Pathogenic shifts in endogenous microbiota impede tissue regeneration via distinct activation of TAK1/MKK/p38

    Arnold, Christopher P; Merryman, M Shane; Harris-Arnold, Aleishia; McKinney, Sean A; Seidel, Chris W; Loethen, Sydney; Proctor, Kylie N; Guo, Longhua; Sánchez Alvarado, Alejandro

    2016-01-01

    The interrelationship between endogenous microbiota, the immune system, and tissue regeneration is an area of intense research due to its potential therapeutic applications. We investigated this relationship in Schmidtea mediterranea, a model organism capable of regenerating any and all of its adult tissues. Microbiome characterization revealed a high Bacteroidetes to Proteobacteria ratio in healthy animals. Perturbations eliciting an expansion of Proteobacteria coincided with ectopic lesions and tissue degeneration. The culture of these bacteria yielded a strain of Pseudomonas capable of inducing progressive tissue degeneration. RNAi screening uncovered a TAK1 innate immune signaling module underlying compromised tissue homeostasis and regeneration during infection. TAK1/MKK/p38 signaling mediated opposing regulation of apoptosis during infection versus normal tissue regeneration. Given the complex role of inflammation in either hindering or supporting reparative wound healing and regeneration, this invertebrate model provides a basis for dissecting the duality of evolutionarily conserved inflammatory signaling in complex, multi-organ adult tissue regeneration. DOI: http://dx.doi.org/10.7554/eLife.16793.001 PMID:27441386

  14. Genomic profiling reveals that transient adipogenic activation is a hallmark of mouse models of skeletal muscle regeneration.

    Laura Lukjanenko

    Full Text Available The marbling of skeletal muscle by ectopic adipose tissue is a hallmark of many muscle diseases, including sarcopenia and muscular dystrophies, and generally associates with impaired muscle regeneration. Although the etiology and the molecular mechanisms of ectopic adipogenesis are poorly understood, fatty regeneration can be modeled in mice using glycerol-induced muscle damage. Using comprehensive molecular and histological profiling, we compared glycerol-induced fatty regeneration to the classical cardiotoxin (CTX-induced regeneration model previously believed to lack an adipogenic response in muscle. Surprisingly, ectopic adipogenesis was detected in both models, but was stronger and more persistent in response to glycerol. Importantly, extensive differential transcriptomic profiling demonstrated that glycerol induces a stronger inflammatory response and promotes adipogenic regulatory networks while reducing fatty acid β-oxidation. Altogether, these results provide a comprehensive mapping of gene expression changes during the time course of two muscle regeneration models, and strongly suggest that adipogenic commitment is a hallmark of muscle regeneration, which can lead to ectopic adipocyte accumulation in response to specific physio-pathological challenges.

  15. Neural stem cells secrete factors facilitating brain regeneration upon constitutive Raf-Erk activation.

    Rhee, Yong-Hee; Yi, Sang-Hoon; Kim, Joo Yeon; Chang, Mi-Yoon; Jo, A-Young; Kim, Jinyoung; Park, Chang-Hwan; Cho, Je-Yoel; Choi, Young-Jin; Sun, Woong; Lee, Sang-Hun

    2016-01-01

    The intracellular Raf-Erk signaling pathway is activated during neural stem cell (NSC) proliferation, and neuronal and astrocytic differentiation. A key question is how this signal can evoke multiple and even opposing NSC behaviors. We show here, using a constitutively active Raf (ca-Raf), that Raf-Erk activation in NSCs induces neuronal differentiation in a cell-autonomous manner. By contrast, it causes NSC proliferation and the formation of astrocytes in an extrinsic autocrine/paracrine manner. Thus, treatment of NSCs with medium (CM) conditioned in ca-Raf-transduced NSCs (Raf-CM; RCM) became activated to form proliferating astrocytes resembling radial glial cells (RGCs) or adult-type NSCs. Infusion of Raf-CM into injured mouse brains caused expansion of the NSC population in the subventricular zone, followed by the formation of new neurons that migrated to the damaged site. Our study shows an example how molecular mechanisms dissecting NSC behaviors can be utilized to develop regenerative therapies in brain disorders. PMID:27554447

  16. Tissue type plasminogen activator regulates myeloid-cell dependent neoangiogenesis during tissue regeneration

    Ohki, Makiko; Ohki, Yuichi; Ishihara, Makoto;

    2010-01-01

    Ischemia of the heart, brain, and limbs is a leading cause of morbidity and mortality worldwide. Treatment with tissue type plasminogen activator (tPA) can dissolve blood clots and can ameliorate the clinical outcome in ischemic diseases. But the underlying mechanism by which tPA improves ischemi...

  17. Modelling and simulation of regenerators with complex flow arrangements for active magnetocaloric refrigeration

    Lei, Tian; Nielsen, Kaspar Kirstein; Engelbrecht, Kurt

    2014-01-01

    Compared to a conventional vapor compression refrigera-tion system, a magnetocaloric refrigerator has many advantages, such as potentially high efficiency, low vibration and avoidance of refrigerants that deplete the ozone layer and cause the green-house effect. As a main component of the active...

  18. Electrically Activated Primary Human Fibroblasts Improve In Vitro and In Vivo Skin Regeneration.

    Rouabhia, Mahmoud; Park, Hyun Jin; Zhang, Ze

    2016-08-01

    Electrical stimulation (ES) changes cellular behaviors and thus constitutes a potential strategy to promote wound healing. However, well-controlled in vitro findings have yet to be translated to in vivo trials. This study was to demonstrate the feasibility and advantages of transplanting electrically activated cells (E-Cells) to help wound healing. Primary human skin fibroblasts were activated through well defined ES and cultured with keratinocytes to generate engineered human skin (EHS), which were transplanted to nu/nu mice. The electrically activated EHS grafts were analyzed at 20 and 30 days post-grafting, showing faster wound closure, thick epidermis, vasculature, and functional basement membrane containing laminin and type IV collagen that were totally produced by the implanted human cells. Because a variety of cells can be electrically activated, E-Cells may become a new cell source and the transplantation of E-Cells may represent a new strategy in wound healing and tissue engineering. J. Cell. Physiol. 231: 1814-1821, 2016. © 2015 Wiley Periodicals, Inc. PMID:26661681

  19. Magnetism and Electricity Activity "Attracts" Student Interest

    Roman, Harry T.

    2010-01-01

    Electricity and magnetism are intimately linked, this relationship forming the basis of the modern electric utility system and the generation of bulk electrical energy. There is rich literature from which to teach students the basics, but nothing drives the point home like having them learn from firsthand experience--and that is what this…

  20. Experimental Contribution to High Precision Characterization of Magnetic Forces in Active Magnetic Bearings

    Kjølhede, Klaus; Santos, Ilmar

    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 vali...... with respect to the instantaneous measured force obtained from the strain gauges signals)...... magnetic forces is conducted using different experimental tests: (a) 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, (b) by measuring the input current and bearing...

  1. Experimental Contribution to High-Precision Characterization of Magnetic Forces in Active Magnetic Bearings

    Kjølhede, Klaus; Santos, Ilmar

    2007-01-01

    Parameter identification procedures and model validation are major steps toward 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 valid...... normalized with respect to the instantaneous measured force obtained from the strain gauges signals)....... the magnetic forces is conducted 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...

  2. Experimental Contribution to High Precision Characterization of Magnetic Forces in Active Magnetic Bearings

    Kjølhede, Klaus; Santos, Ilmar

    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 vali...... with respect to the instantaneous measured force obtained from the strain gauges signals)...... magnetic forces is conducted using different experimental tests: (a) 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, (b) by measuring the input current and bearing...

  3. Stellar magnetic activity – Star-Planet Interactions

    Poppenhaeger, K.

    2015-01-01

    Full Text Available Stellar magnetic activity is an important factor in the formation and evolution of exoplanets. Magnetic phenomena like stellar flares, coronal mass ejections, and high-energy emission affect the exoplanetary atmosphere and its mass loss over time. One major question is whether the magnetic evolution of exoplanet host stars is the same as for stars without planets; tidal and magnetic interactions of a star and its close-in planets may play a role in this. Stellar magnetic activity also shapes our ability to detect exoplanets with different methods in the first place, and therefore we need to understand it properly to derive an accurate estimate of the existing exoplanet population. I will review recent theoretical and observational results, as well as outline some avenues for future progress.

  4. Tests of an Induced Activity Monitor in a magnetic environment

    Pangallo, M; Perrot, Anne Laure; Vincke, H; CERN. Geneva. TS Department

    2005-01-01

    The Induced Activity Monitors (IAM) dedicated to measure the gamma ambient dose equivalent rate (due to the photons from the activated materials) will be installed inside the LHC accelerator and in the experimental caverns. Some of these IAM detectors (plastic ionization chambers) will be located in areas were magnetic fields will be present. Therefore the response of such radiation detectors in a magnetic field environment has been experimentally and theoretically studied and the results are reported in this note. The tests were performed at CERN in the CMS H2 experimental area with conventional and superconductor magnets. The response of the IAM was studied for different orientations of its chamber with respect to the magnetic field lines and for different magnetic field intensities up to 3T. Moreover, FLUKA Monte Carlo Simulations were performed to fully understand the physical effects responsible for the various measurement results. The conclusions of this study will permit to choose the proper orientatio...

  5. Characteristics of particle number and mass emissions during heavy-duty diesel truck parked active DPF regeneration in an ambient air dilution tunnel

    Yoon, Seungju; Quiros, David C.; Dwyer, Harry A.; Collins, John F.; Burnitzki, Mark; Chernich, Donald; Herner, Jorn D.

    2015-12-01

    Diesel particle number and mass emissions were measured during parked active regeneration of diesel particulate filters (DPF) in two heavy-duty diesel trucks: one equipped with a DPF and one equipped with a DPF + SCR (selective catalytic reduction), and compliant with the 2007 and 2010 emission standards, respectively. The emission measurements were conducted using an ambient air dilution tunnel. During parked active regeneration, particulate matter (PM) mass emissions measured from a 2007 technology truck were significantly higher than the emissions from a 2010 technology truck. Particle number emissions from both trucks were dominated by nucleation mode particles having a diameter less than 50 nm; nucleation mode particles were orders of magnitude higher than accumulation mode particles having a diameter greater than 50 nm. Accumulation mode particles contributed 77.8 %-95.8 % of the 2007 truck PM mass, but only 7.3 %-28.2 % of the 2010 truck PM mass.

  6. Comparisons of kinetics, thermodynamics and regeneration of tetramethylammonium hydroxide adsorption in aqueous solution with graphene oxide, zeolite and activated carbon

    Chang, Shenteng; Lu, Chungsying, E-mail: clu@nchu.edu.tw; Lin, Kun-Yi Andrew

    2015-01-30

    Graphical abstract: A comparison of TMAH adsorption capacity with GO, NaY and GAC is conducted and the result reveals that the magnitude of qe follows the order of GO > NaY > GAC. The adsorption capacity of GO is significantly higher than those of zeolite and activated carbon in this and reported studies, showing its encouraging potential. GO also exhibits good reversibility of TMAH adsorption through 10 cycles of adsorption and desorption process. This reflects that GO is a promising and efficient adsorbent for TMAH removal in wastewater treatment. - Highlights: • Adsorption kinetics and isotherms of TMAH to GO, NaY and GAC are compared. • Thermodynamics of TMAH adsorption to GO, NaY and GAC is determined. • GO exhibits the highest TMAH adsorption capacity, followed by NaY and GAC. • Recyclabilities of NaY and GO remain above 95% but that of GAC dropped to 70%. - Abstract: Graphene oxide (GO), sodium Y-type zeolite (NaY) and granular activated carbon (GAC) are selected as adsorbents to study their kinetics, thermodynamics and regeneration of tetramethylammonium hydroxide (TMAH) adsorption from water. The adsorption kinetics follows the pseudo-second-order rate law while the adsorption thermodynamics shows an exothermic reaction with GO and GAC but displays an endothermic reaction with NaY. The adsorbed TMAH can be readily desorbed from the surface of GO and NaY by 0.05 M NaCl solution. A comparative study on the cyclic TMAH adsorption with GO, NaY and GAC is also conducted and the results reveal that GO exhibits the greatest TMAH adsorption capacity as well as superior reversibility of TMAH adsorption over 10 cycles of adsorption and desorption process. These features indicate that GO is a promising and efficient adsorbent for TMAH removal in wastewater treatment.

  7. Comparisons of kinetics, thermodynamics and regeneration of tetramethylammonium hydroxide adsorption in aqueous solution with graphene oxide, zeolite and activated carbon

    Graphical abstract: A comparison of TMAH adsorption capacity with GO, NaY and GAC is conducted and the result reveals that the magnitude of qe follows the order of GO > NaY > GAC. The adsorption capacity of GO is significantly higher than those of zeolite and activated carbon in this and reported studies, showing its encouraging potential. GO also exhibits good reversibility of TMAH adsorption through 10 cycles of adsorption and desorption process. This reflects that GO is a promising and efficient adsorbent for TMAH removal in wastewater treatment. - Highlights: • Adsorption kinetics and isotherms of TMAH to GO, NaY and GAC are compared. • Thermodynamics of TMAH adsorption to GO, NaY and GAC is determined. • GO exhibits the highest TMAH adsorption capacity, followed by NaY and GAC. • Recyclabilities of NaY and GO remain above 95% but that of GAC dropped to 70%. - Abstract: Graphene oxide (GO), sodium Y-type zeolite (NaY) and granular activated carbon (GAC) are selected as adsorbents to study their kinetics, thermodynamics and regeneration of tetramethylammonium hydroxide (TMAH) adsorption from water. The adsorption kinetics follows the pseudo-second-order rate law while the adsorption thermodynamics shows an exothermic reaction with GO and GAC but displays an endothermic reaction with NaY. The adsorbed TMAH can be readily desorbed from the surface of GO and NaY by 0.05 M NaCl solution. A comparative study on the cyclic TMAH adsorption with GO, NaY and GAC is also conducted and the results reveal that GO exhibits the greatest TMAH adsorption capacity as well as superior reversibility of TMAH adsorption over 10 cycles of adsorption and desorption process. These features indicate that GO is a promising and efficient adsorbent for TMAH removal in wastewater treatment

  8. Magnetic Levitation Technique for Active Vibration Control

    Hoque, Emdadul; Mizuno, Takeshi

    2010-01-01

    A zero-power controlled magnetic levitation system has been presented in this chapter. The unique characteristic of the zero-power control system is that it can generate negative stiffness with zero control current in the steady-state which is realized in this chapter. The detail characteristics of the levitation system are investigated. Moreover, two major contributions, the stiffness adjustment and nonlinear compensation of the suspension system have been introduced elaborately. Often, ther...

  9. Magnetic structure of an activated filament in a flaring active region

    Sasso, C; Solanki, S K

    2013-01-01

    While the magnetic field in quiescent prominences has been widely investigated, less is known about the field in activated prominences. We introduce observational results on the magnetic field structure of an activated filament in a flaring active region. We study, in particular, its magnetic structure and line-of-sight flows during its early activated phase, shortly before it displays signs of rotation. We invert the Stokes profiles of the chromospheric He I 10830 A triplet and the photospheric Si I 10827 A line observed in this filament by the VTT on Tenerife. Using these inversion results we present and interpret the first maps of velocity and magnetic field obtained in an activated filament, both in the photosphere and the chromosphere. Up to 5 different magnetic components are found in the chromospheric layers of the filament, while outside the filament a single component is sufficient to reproduce the observations. Magnetic components displaying an upflow are preferentially located towards the centre of...

  10. Optimization of active magnetic bearings for automotive flywheel energy storage systems based on soft magnetic materials

    Wegleiter H.

    2013-01-01

    Full Text Available For active magnetically suspended rotors in mobile flywheel energy storage systems the lowest possible weight, smallest size and a low price is required. Since the flywheel is operated in vacuum and very little heat can be dissipated from the rotor, the bearing’s magnetic losses have to be as minimal as well. This paper compares the design and optimization of homopolar radial active magnetic bearings with 3 different types of laminated steel. The first type is a standard transformer steel, the second one is high flux cobalt steel and the third one is high flux cobalt steel with high tensile strength.

  11. Deciphering Solar Magnetic Activity: On Grand Minima in Solar Activity

    Scott William Mcintosh; Leamon, Robert J.

    2015-01-01

    The Sun provides the energy necessary to sustain our existence. While the Sun provides for us, it is also capable of taking away. The weather and climatic scales of solar evolution and the Sun-Earth connection are not well understood. There has been tremendous progress in the century since the discovery of solar magnetism - magnetism that ultimately drives the electromagnetic, particulate and eruptive forcing of our planetary system. There is contemporary evidence of a decrease in solar magne...

  12. Deciphering solar magnetic activity: on grand minima in solar activity

    Mcintosh, Scott W.; Leamon, Robert J.

    2015-01-01

    The Sun provides the energy necessary to sustain our existence. While the Sun provides for us, it is also capable of taking away. The weather and climatic scales of solar evolution and the Sun-Earth connection are not well understood. There has been tremendous progress in the century since the discovery of solar magnetism - magnetism that ultimately drives the electromagnetic, particulate and eruptive forcing of our planetary system. There is contemporary evidence of a decrease in solar magne...

  13. Stimulating endogenous cardiac regeneration

    Amanda eFinan

    2015-09-01

    Full Text Available The healthy adult heart has a low turnover of cardiac myocytes. The renewal capacity, however, is augmented after cardiac injury. Participants in cardiac regeneration include cardiac myocytes themselves, cardiac progenitor cells, and peripheral stem cells, particularly from the bone marrow compartment. Cardiac progenitor cells and bone marrow stem cells are augmented after cardiac injury, migrate to the myocardium, and support regeneration. Depletion studies of these populations have demonstrated their necessary role in cardiac repair. However, the potential of these cells to completely regenerate the heart is limited. Efforts are now being focused on ways to augment these natural pathways to improve cardiac healing, primarily after ischemic injury but in other cardiac pathologies as well. Cell and gene therapy or pharmacological interventions are proposed mechanisms. Cell therapy has demonstrated modest results and has passed into clinical trials. However, the beneficial effects of cell therapy have primarily been their ability to produce paracrine effects on the cardiac tissue and recruit endogenous stem cell populations as opposed to direct cardiac regeneration. Gene therapy efforts have focused on prolonging or reactivating natural signaling pathways. Positive results have been demonstrated to activate the endogenous stem cell populations and are currently being tested in clinical trials. A potential new avenue may be to refine pharmacological treatments that are currently in place in the clinic. Evidence is mounting that drugs such as statins or beta blockers may alter endogenous stem cell activity. Understanding the effects of these drugs on stem cell repair while keeping in mind their primary function may strike a balance in myocardial healing. To maximize endogenous cardiac regeneration,a combination of these approaches couldameliorate the overall repair process to incorporate the participation ofmultiple cell players.

  14. Development of a rotary magnetic refrigerator

    Tusek, Jaka; Zupan, Samo; Sarlah, Alen; Prebil, Ivan; Poredos, Alojz [University of Ljubljana, Faculty of Mechanical Engineering, Askerceva c. 6, 1000 Ljubljana (Slovenia)

    2010-03-15

    A team of researchers have developed and built a prototype of a rotary magnetic refrigerator (MR). The principle of the operation of the presented magnetic refrigerator is based on the rotary movement of active magnetic regenerators (AMRs) with a magnetocaloric material and on the magnetic field generated by permanent magnets Nd-Fe-B. The first part of the paper presents the development and analysis of the structure for generating the magnetic field and the basic operational principle of the magnetic refrigerator concerned, and the second part gives a description of the development process for certain key elements of the complete magnetic refrigeration system. (author)

  15. Comparing superconducting and permanent magnets for magnetic refrigeration

    Bjørk, R.; Nielsen, K. K.; Bahl, C. R. H.; Smith, A.; Wulff, A. C.

    2016-05-01

    We compare the cost of a high temperature superconducting (SC) tape-based solenoid with a permanent magnet (PM) Halbach cylinder for magnetic refrigeration. Assuming a five liter active magnetic regenerator volume, the price of each type of magnet is determined as a function of aspect ratio of the regenerator and desired internal magnetic field. It is shown that to produce a 1 T internal field in the regenerator a permanent magnet of hundreds of kilograms is needed or an area of superconducting tape of tens of square meters. The cost of cooling the SC solenoid is shown to be a small fraction of the cost of the SC tape. Assuming a cost of the SC tape of 6000 /m2 and a price of the permanent magnet of 100 /kg, the superconducting solenoid is shown to be a factor of 0.3-3 times more expensive than the permanent magnet, for a desired field from 0.5-1.75 T and the geometrical aspect ratio of the regenerator. This factor decreases for increasing field strength, indicating that the superconducting solenoid could be suitable for high field, large cooling power applications.

  16. Para-aminobenzamidine linked regenerated cellulose membranes for plasminogen activator purification: Effect of spacer arm length and ligand density

    Fasoli, Ezio; Reyes, Yiaslin Ruiz; Guzman, Osiris Martinez; Rosado, Alexandra; Cruz, Vivian Rodriguez; Borges, Amaris; Martinez, Edmarie; Bansal, Vibha

    2013-01-01

    Despite membrane-based separations offering superior alternative to packed bed chromatographic processes, there has been a substantial lacuna in their actual application to separation processes. One of the major reasons behind this is the lack of availability of appropriately modified or end-group modifiable membranes. In this paper, an affinity membrane was developed using a commercially available serine protease inhibitor, para-aminobenzamidine (pABA). The membrane modification was optimized for protein binding capacity by varying: i) the length of the spacer arm (SA; 5-atoms, 7-atoms, and 14-atoms) linking the ligand to membrane surface; ii) the affinity ligand (pABA) density on membrane surface (5–25 nmoles per cm2). Resulting membranes were tested for their ability to bind plasminogen activators (PAs) from mono- and multi- component systems in batch mode. The membrane containing pABA linked through 7-atoms SA but similar ligand density as in the case of 5- or 14- atoms long SA was found to bind up to 1.6-times higher amounts of PA per nmole of immobilized ligand from conditioned HeLa cell culture media. However, membranes with similar ligand densities but different lengths of SA, showed comparable binding capacities in monocomponent system. In addition, the length of SA did not affect the selectivity of the ligand for PA. A clear inverse linear correlation was observed between ligand density and binding capacity until the point of PA binding optima was reached (11±1.0 nmoles per cm2) in mono- and multi- component systems for 7- as well as 14- atoms SA. Up to 200-fold purification was achieved in a single step separation of PA from HeLa conditioned media using these affinity membranes. The issues of ligand leaching and reuse of the membranes were also investigated. An extensive regeneration procedure allowed the preservation of approximately 95% of the PA binding capacity of the membranes even after five cycles of use. PMID:23703544

  17. The role of proteasome beta subunits in gastrin-mediated transcription of plasminogen activator inhibitor-2 and regenerating protein1.

    Adrian O'Hara

    Full Text Available The hormone gastrin physiologically regulates gastric acid secretion and also contributes to maintaining gastric epithelial architecture by regulating expression of genes such as plasminogen activator inhibitor 2 (PAI-2 and regenerating protein 1 (Reg1. Here we examine the role of proteasome subunit PSMB1 in the transcriptional regulation of PAI-2 and Reg1 by gastrin, and its subcellular distribution during gastrin stimulation. We used the gastric cancer cell line AGS, permanently transfected with the CCK2 receptor (AGS-GR to study gastrin stimulated expression of PAI-2 and Reg1 reporter constructs when PSMB1 was knocked down by siRNA. Binding of PSMB1 to the PAI-2 and Reg1 promoters was assessed by chromatin immunoprecipitation (ChIP assay. Subcellular distribution of PSMB1 was determined by immunocytochemistry and Western Blot. Gastrin robustly increased expression of PAI-2 and Reg1 in AGS-GR cells, but when PSMB1 was knocked down the responses were dramatically reduced. In ChIP assays, following immunoprecipitation of chromatin with a PSMB1 antibody there was a substantial enrichment of DNA from the gastrin responsive regions of the PAI-2 and Reg1 promoters compared with chromatin precipitated with control IgG. In AGS-GR cells stimulated with gastrin there was a significant increase in the ratio of nuclear:cytoplasmic PSMB1 over the same timescale as recruitment of PSMB1 to the PAI-2 and Reg1 promoters seen in ChIP assays. We conclude that PSMB1 is part of the transcriptional machinery required for gastrin stimulated expression of PAI-2 and Reg1, and that its change in subcellular distribution in response to gastrin is consistent with this role.

  18. The connection between stellar activity cycles and magnetic field topology

    See, V.; Jardine, M.; Vidotto, A. A.; Donati, J.-F.; Boro Saikia, S.; Bouvier, J.; Fares, R.; Folsom, C. P.; Gregory, S. G.; Hussain, G.; Jeffers, S. V.; Marsden, S. C.; Morin, J.; Moutou, C.; do Nascimento, J. D.; Petit, P.; Waite, I. A.

    2016-08-01

    Zeeman Doppler imaging has successfully mapped the large-scale magnetic fields of stars over a large range of spectral types, rotation periods and ages. When observed over multiple epochs, some stars show polarity reversals in their global magnetic fields. On the Sun, polarity reversals are a feature of its activity cycle. In this paper, we examine the magnetic properties of stars with existing chromospherically determined cycle periods. Previous authors have suggested that cycle periods lie on multiple branches, either in the cycle period-Rossby number plane or the cycle period-rotation period plane. We find some evidence that stars along the active branch show significant average toroidal fields that exhibit large temporal variations while stars exclusively on the inactive branch remain dominantly poloidal throughout their entire cycle. This lends credence to the idea that different shear layers are in operation along each branch. There is also evidence that the short magnetic polarity switches observed on some stars are characteristic of the inactive branch while the longer chromospherically determined periods are characteristic of the active branch. This may explain the discrepancy between the magnetic and chromospheric cycle periods found on some stars. These results represent a first attempt at linking global magnetic field properties obtained form ZDI and activity cycles.

  19. Activation of satellite cells and the regeneration of human skeletal muscle are expedited by ingestion of nonsteroidal anti-inflammatory medication.

    Mackey, Abigail L; Rasmussen, Lotte K; Kadi, Fawzi; Schjerling, Peter; Helmark, Ida C; Ponsot, Elodie; Aagaard, Per; Durigan, João Luiz Q; Kjaer, Michael

    2016-06-01

    With this study we investigated the role of nonsteroidal anti-inflammatory drugs (NSAIDs) in human skeletal muscle regeneration. Young men ingested NSAID [1200 mg/d ibuprofen (IBU)] or placebo (PLA) daily for 2 wk before and 4 wk after an electrical stimulation-induced injury to the leg extensor muscles of one leg. Muscle biopsies were collected from the vastus lateralis muscles before and after stimulation (2.5 h and 2, 7, and 30 d) and were assessed for satellite cells and regeneration by immunohistochemistry and real-time RT-PCR, and we also measured telomere length. After injury, and compared with PLA, IBU was found to augment the proportion of ActiveNotch1(+) satellite cells at 2 d [IBU, 29 ± 3% vs. PLA, 19 ± 2% (means ± sem)], satellite cell content at 7 d [IBU, 0.16 ± 0.01 vs. PLA, 0.12 ± 0.01 (Pax7(+) cells/fiber)], and to expedite muscle repair at 30 d. The PLA group displayed a greater proportion of embryonic myosin(+) fibers and a residual ∼2-fold increase in mRNA levels of matrix proteins (all P muscle remodeling during large-scale regeneration of injured human skeletal muscle.-Mackey, A. L., Rasmussen, L. K., Kadi, F., Schjerling, P., Helmark, I. C., Ponsot, E., Aagaard, P., Durigan, J. L. Q., Kjaer, M. Activation of satellite cells and the regeneration of human skeletal muscle are expedited by ingestion of nonsteroidal anti-inflammatory medication. PMID:26936358

  20. Whirling Dervish Dynamos: Magnetic Activity in CV Secondaries

    Saar, Steven

    2003-07-01

    The mass-losing secondary stars of cataclysmic variables {CVs} are the most rapidly rotating cool dwarfs observable. Other rapid rotators show a maximal, "saturated" level of magnetic activity {e.g., X-ray emission}, but there are hints from contact binaries and young clusters that activity may be suppressed at the highest rotation rates. CV secondaries are thus important probes of magnetic dynamos at rotational extremes. Implications for CV evolution {e.g., the ``period gap", accretion variability} may also be profound. Unfortunately, study of CV secondaries is hampered by pesky accretion-related phenomena and reflection effects. As a result, little systematic work has been done. To explore activity in these stars, we therefore propose to study far-UV spectra of AM Her-type systems {which have no accretion disks} in deep photometric minima in which accretion is shut off. Magnetic-related emission from the secondary will be separated {in velocity} from residual accretion emission by observations near quadratures. Lower chromospheric irradiation due to the white dwarf primary will be removed by modeling, yielding the true level of magnetic activity on the secondary. We will compare the results to other dMe stars and draw implications for magnetic dynamos and activity at rotational extremes, and for CV evolution and behavior.

  1. Adsorption of Imidacloprid on Powdered Activated Carbon and Magnetic Activated Carbon

    Zahoor, M.; Mahramanlioglu, M.

    2011-01-01

    The adsorptive characteristics of imidacloprid on magnetic activated carbon (MAC12) in comparison to powdered activated carbon (PAC) were investigated. Adsorption of imidacloprid onto powdered activated carbon and magnetic activated carbon was studied as a function of time, initial imidacloprid concentration, temperature and pH. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models for both carbons were used to describe the kinetic data. The adsorption equilibrium data we...

  2. Magnetic flare model of quasars and active galactic nuclei

    As a model of quasars and active galactic nuclei, we present the magnetic flare model which clarifies the connection between the primary energy source and the non-thermal phenomena. The behavior of the magnetic field generated in the accretion disk around a massive black hole is investigated in terms of the αω-dynamo and the magnetic buoyancy. The magnetic field is responsible not only for the angular momentum transfer but also for the vertical energy transfer owing to the magnetic buoyancy. Magnetic energy thus transferred should be released in the coronal region above the disk surface through its flare-like reconnection as in the solar flare. We expect that it will produce a variety of non-thermal activities characteristic to quasars and active galactic nuclei. We argue that the following scenario is compatible with various observations: A flare generates the relativistic shock behind which electrons are heated up to the relativistic energy. Subsequently, they produce X and γ rays by the inverse Compton scattering of low energy photons as well as emit from radio up to soft X photons by the synchrotron radiation. (author)

  3. Valproic acid induces hair regeneration in murine model and activates alkaline phosphatase activity in human dermal papilla cells.

    Soung-Hoon Lee

    Full Text Available BACKGROUND: Alopecia is the common hair loss problem that can affect many people. However, current therapies for treatment of alopecia are limited by low efficacy and potentially undesirable side effects. We have identified a new function for valproic acid (VPA, a GSK3β inhibitor that activates the Wnt/β-catenin pathway, to promote hair re-growth in vitro and in vivo. METHODOLOGY/ PRINCIPAL FINDINGS: Topical application of VPA to male C3H mice critically stimulated hair re-growth and induced terminally differentiated epidermal markers such as filaggrin and loricrin, and the dermal papilla marker alkaline phosphatase (ALP. VPA induced ALP in human dermal papilla cells by up-regulating the Wnt/β-catenin pathway, whereas minoxidil (MNX, a drug commonly used to treat alopecia, did not significantly affect the Wnt/β-catenin pathway. VPA analogs and other GSK3β inhibitors that activate the Wnt/β-catenin pathway such as 4-phenyl butyric acid, LiCl, and BeCl(2 also exhibited hair growth-promoting activities in vivo. Importantly, VPA, but not MNX, successfully stimulate hair growth in the wounds of C3H mice. CONCLUSIONS/ SIGNIFICANCE: Our findings indicate that small molecules that activate the Wnt/β-catenin pathway, such as VPA, can potentially be developed as drugs to stimulate hair re-growth.

  4. Investigation of magnetic active core sizes and hydrodynamic diameters of a magnetically fractionated ferrofluid

    In this work we address the question which relates between the size of the magnetically active core of magnetic nanoparticles (MNPs) and the size of the overall particle in the solution (the so-called hydrodynamic diameter dhyd) exists. For this purpose we use two methods of examination that can deliver conclusions about the properties of MNP which are not accessible with normal microscopy. On the one hand, we use temperature dependent magnetorelaxation (TMRX) method, which enables direct access to the energy barrier distribution and by using additional hysteresis loop measurements can provide details about the size of the magnetically active cores. On the other hand, to determine the size of the overall particle in the solution, we use the magnetooptical relaxation of ferrofluids (MORFF) method, where the stimulation is done magnetically while the reading of the relaxation signal, however, is done optically. As a basis for the examinations in this work we use a ferrofluid that was developed for medicinal purposes and which has been fractioned magnetically to obtain differently sized fractions of MNPs. The two values obtained through these methods for each fraction shows the success in fractioning the original solution. Therefore, one can conclude a direct correlation between the size of the magnetically active core and the size of the complete particle in the solution from the experimental results. To calculate the size of the magnetically active core we found a temperature dependent anisotropy constant which was taken into account for the calculations. Furthermore, we found relaxation signals at 18 K for all fractions in these TMRX measurements, which have their origin in other magnetic effects than the Néel relaxation.

  5. Modulation of ornithine decarboxylase activity in the normal and regenerating rat liver by various doses of the peptide morphogen of Hydra

    Yarygin, K.N.; Kazimirskii, A.N.; Kositskii, G.I.; Rubina, A.Yu.; Vinogradov, V.A.; Pylaev, A.S.

    1986-11-01

    In this investigation, changes in ornithine decarboxylase (ODC) activity were studied in the normal and regenerating liver of rats receiving injections of various doses of Hydra peptide morphogen (HPM). Activity of ODC was determined by a radioisotope method based on liberation of /sup 14/CO/sub 2/ from L-(1-/sup 14/C)-ornithine. The results indicate in the author's opinion that HPM may have a role in the regulation of anabolic processes and, in particular, of regenerative processes in mammals.

  6. The evaluation of the activity of medicinal remedies of plant and animal origin on the regeneration of the earthworms′ tail segments

    Viktor Alexandrovich Bybin

    2015-01-01

    Full Text Available Now, in the global community there is enough hard recommendation to replace the vertebrate test animals into simpler organisms at the development, testing, and evaluation of the quality pharmaceuticals. The feature of planarian to regenerate in new individual planarian from a piece, which is only 1/7 of the original animal, allowed to create the alternative methods of testing of drugs, dietary supplements, water quality, influence of electromagnetic fields, and other radiations. The tests on planarian can replace the ones that are held today on mammals. However, the lacks of the bioassays based on the planarian regeneration are the need for complex and expensive video equipment for recording the regrowth of worms′ body, the difficulties of culturing of flatworms and fairly long period of response. These difficulties can be avoided by using another group of the worms of type Annelida. The new individual can be fully recovered only from the front half of the body in many species of earthworms. Thus, the influence of the pharmaceuticals from earthworms, mummy, and Orthilia secunda on the ability of earthworms to regenerate lost tail segments has been investigated. The relations of the activity of preparations tested with doses and the time of the storage have been revealed. The principal possibility of applicability of the test reaction studied as a way to evaluate the effects and quality of remedies based on medicinal plants and earthworms has been shown.

  7. Measurements of flux pumping activation of trapped field magnets

    Weinstein, Roy; Parks, Drew; Sawh, Ravi-Persad [Texas Center for Superconductivity, 202 Houston Science Center, University of Houston, Houston, TX 77204-5002 (United States); Davey, Kent [Physics Department, 617 Science and Research Building I, University of Houston, Houston, TX 77204-5005 (United States)

    2010-11-15

    Large grains of high temperature superconducting (HTS) material can be utilized as trapped field magnets (TFMs). Persistent currents are set up in the HTS when it is cooled in a magnetic field, or exposed to a magnetic field after cooling. TFMs have been improved over the past two decades by the efforts of a large number of worldwide research groups. However, applications using TFMs have lagged, in part due to the problem of high fields needed for activation. We describe herein experiments designed to observe the behaviour of TFM activation using repeated applications of low fields (called 'pumping'). Significant partial activation is obtained using a non-uniform pumping field (e.g., a small permanent magnet) which is higher in the centre of the HTS than at the periphery. Cooling in zero field followed by pumping with such a field results in trapping the full applied field, in comparison to half of the applied field being trapped by cooling in zero field followed by application of a uniform field. We find that for partial activation by cooling in a field and subsequent activation by pumping, the resulting fields are additive. We also conclude that for activation by fluxoid pumping, creep assists the process.

  8. Functional magnetic resonance imaging of higher brain activity

    Functional magnetic resonance images (fMRIs) exhibit small differences in the magnetic resonance signal intensity in positions corresponding to focal areas of brain activation. These signal are caused by variation in the oxygenation state of the venous vasculature. Using this non-invasive and dynamic method, it is possible to localize functional brain activation, in vivo, in normal individuals, with an accuracy of millimeters and a temporal resolution of seconds. Though a series of technical difficulties remain, fMRI is increasingly becoming a key method for visualizing the working brain, and uncovering the topographical organization of the human brain, and understanding the relationship between brain and the mind

  9. Tissue regeneration with photobiomodulation

    Tang, Elieza G.; Arany, Praveen R.

    2013-03-01

    Low level light therapy (LLLT) has been widely reported to reduce pain and inflammation and enhance wound healing and tissue regeneration in various settings. LLLT has been noted to have both stimulatory and inhibitory biological effects and these effects have been termed Photobiomodulation (PBM). Several elegant studies have shown the key role of Cytochrome C oxidase and ROS in initiating this process. The downstream biological responses remain to be clearly elucidated. Our work has demonstrated activation of an endogenous latent growth factor complex, TGF-β1, as one of the major biological events in PBM. TGF-β1 has critical roles in various biological processes especially in inflammation, immune responses, wound healing and stem cell biology. This paper overviews some of the studies demonstrating the efficacy of PBM in promoting tissue regeneration.

  10. Simulation of magnetic active polymers for versatile microfluidic devices

    Gusenbauer, Markus; Fischbacher, Johann; Reichel, Franz; Exl, Lukas; Bance, Simon; Kataeva, Nadezhda; Binder, Claudia; Brückl, Hubert; Schrefl, Thomas

    2013-01-01

    We propose to use a compound of magnetic nanoparticles (20-100 nm) embedded in a flexible polymer (Polydimethylsiloxane PDMS) to filter circulating tumor cells (CTCs). The analysis of CTCs is an emerging tool for cancer biology research and clinical cancer management including the detection, diagnosis and monitoring of cancer. The combination of experiments and simulations lead to a versatile microfluidic lab-on-chip device. Simulations are essential to understand the influence of the embedded nanoparticles in the elastic PDMS when applying a magnetic gradient field. It combines finite element calculations of the polymer, magnetic simulations of the embedded nanoparticles and the fluid dynamic calculations of blood plasma and blood cells. With the use of magnetic active polymers a wide range of tunable microfluidic structures can be created. The method can help to increase the yield of needed isolated CTCs.

  11. Thermal investigations of a room temperature magnetic refrigerator

    Smaili, Arezki; Chiba, Younes [Ecole Nationale Polytechnique d' Alger (Algeria)], email: arezki.smaili@enp.edu.dz

    2011-07-01

    Magnetic refrigeration is a concept based on the magnetocaloric effect that some materials exhibit when the external magnetic field changes. The aim of this paper is to assess the performance of a numerical model in predicting parameters of an active magnetic regenerator refrigerator. Numerical simulations were conducted to perform a thermal analysis on an active magnetic regenerator refrigerator operating near room temperature with and without applied cooling load. Curves of temperature span, cooling capacity and thermal efficiency as functions of the operating conditions were drawn and are presented in this paper. Results showed that at fixed frequency Ql versus mf has an optimum and COP was increased with cycle frequency values. This study demonstrated that the proposed numerical model could be used to predict parameters of an active magnetic regenerator refrigerator as it provides consistent results.

  12. Performance-oriented Analysis of a Hybrid magnetic Assembly for a Heat-pump Magnetocaloric Device

    Insinga, Andrea Roberto; Smith, Anders; Bahl, Christian R.H.; Bjørk, Rasmus

    2014-01-01

    Conventional active-regenerator magnetocaloric devices include moving parts, with the purpose of generating an oscillating magnetic field in the magneto-caloric material, placed inside the regenerator. In this work a different design is analyzed, for application in a magnetocaloric heat pump. In...

  13. MAGNET

    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...

  14. Dendrite Injury Triggers DLK-Independent Regeneration

    Michelle C. Stone

    2014-01-01

    Full Text Available Axon injury triggers regeneration through activation of a conserved kinase cascade, which includes the dual leucine zipper kinase (DLK. Although dendrites are damaged during stroke, traumatic brain injury, and seizure, it is not known whether mature neurons monitor dendrite injury and initiate regeneration. We probed the response to dendrite damage using model Drosophila neurons. Two larval neuron types regrew dendrites in distinct ways after all dendrites were removed. Dendrite regeneration was also triggered by injury in adults. Next, we tested whether dendrite injury was initiated with the same machinery as axon injury. Surprisingly, DLK, JNK, and fos were dispensable for dendrite regeneration. Moreover, this MAP kinase pathway was not activated by injury to dendrites. Thus, neurons respond to dendrite damage and initiate regeneration without using the conserved DLK cascade that triggers axon regeneration.

  15. Measuring starspots on magnetically active stars with the VLTI

    Wittkowski, M; Hubrig, S; Posselt, B; Von der Lühe, O

    2002-01-01

    We present feasibility studies to directly image stellar surface features, which are caused by magnetic activity, with the Very Large Telescope Interferometer (VLTI). We concentrate on late type magnetically active stars, for which the distribution of starspots on the surface has been inferred from photometric and spectroscopic imaging analysis. The study of the surface spot evolution during consecutive rotation cycles will allow first direct measurements (apart from the Sun) of differential rotation which is the central ingredient of magnetic dynamo processes. The VLTI will provide baselines of up to 200 m, and two scientific instruments for interferometric studies at near- and mid-infrared wavelengths. Imaging capabilities will be made possible by closure-phase techniques. We conclude that a realistically modeled cool surface spot can be detected on stars with angular diameters exceeding ~2 mas using the VLTI with the first generation instrument AMBER. The spot parameters can then be derived with reasonable...

  16. Stellar Magnetic Dynamos and Activity Cycles

    Wright, Nicholas J

    2013-01-01

    Using a new uniform sample of 824 solar and late-type stars with measured X-ray luminosities and rotation periods we have studied the relationship between rotation and stellar activity that is believed to be a probe of the underlying stellar dynamo. Using an unbiased subset of the sample we calculate the power law slope of the unsaturated regime of the activity -- rotation relationship as $L_X/L_{bol}\\propto Ro^\\beta$, where $\\beta=-2.70\\pm0.13$. This is inconsistent with the canonical $\\beta = -2$ slope to a confidence of 5$\\sigma$ and argues for an interface-type dynamo. We map out three regimes of coronal emission as a function of stellar mass and age, using the empirical saturation threshold and theoretical super-saturation thresholds. We find that the empirical saturation timescale is well correlated with the time at which stars transition from the rapidly rotating convective sequence to the slowly rotating interface sequence in stellar spin-down models. This may be hinting at fundamental changes in the ...

  17. Loss of Dnmt1 catalytic activity reveals multiple roles for DNA methylation during pancreas development and regeneration

    Anderson, Ryan M.; Bosch, Justin A.; Goll, Mary G.; Hesselson, Daniel; Dong, P. Duc Si; Shin, Donghun; Chi, Neil C.; Shin, Chong Hyun; Schlegel, Amnon; Halpern, Marnie; Stainier, Didier Y.R.

    2009-01-01

    Developmental mechanisms regulating gene expression and the stable acquisition of cell fate direct cytodifferentiation during organogenesis. Moreover, it is likely that such mechanisms could be exploited to repair or regenerate damaged organs. DNA methyltransferases (Dnmts) are enzymes critical for epigenetic regulation, and are used in concert with histone methylation and acetylation to regulate gene expression and maintain genomic integrity and chromosome structure. We carried out two forwa...

  18. Designing a magnet for magnetic refrigeration

    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 helicity and energy spectra of a solar active region

    Zhang, Hongqi; Sokoloff, D D

    2013-01-01

    We compute magnetic helicity and energy spectra of the solar active region NOAA 11158 during 11-15 February 2011 at 20 degr southern heliographic latitude using observational photospheric vector magnetograms. We adopt the isotropic representation of the Fourier-transformed two-point correlation tensor of the magnetic field. The sign of magnetic helicity turns out to be predominantly positive at all wavenumbers. This sign is consistent with what is theoretically expected for the southern hemisphere. The relative magnetic helicity is around 8% and strongest at intermediate wavenumbers of k ~ 0.4 Mm^{-1}, corresponding to a scale of 2 pi/k ~ 16 Mm. The same sign and a somewhat smaller value is also found for the relative current helicity evaluated in real space based on the vertical components of magnetic field and current density. The current helicity spectrum is estimated from the magnetic helicity spectrum and its modulus shows a k^{-5/3} spectrum at large wavenumbers. A similar power law is also obtained for...

  20. Dynamics of an active magnetic particle in a rotating magnetic field.

    Cēbers, A; Ozols, M

    2006-02-01

    The motion of an active (self-propelling) particle with a permanent magnetic moment under the action of a rotating magnetic field is considered. We show that below a critical frequency of the external field the trajectory of a particle is a circle. For frequencies slightly above the critical point the particle moves on an approximately circular trajectory and from time to time jumps to another region of space. Symmetry of the particle trajectory depends on the commensurability of the field period and the period of the orientational motion of the particle. We also show how our results can be used to study the properties of naturally occurring active magnetic particles, so-called magnetotactic bacteria. PMID:16605340

  1. Edge Adapted Wavelets, Solar Magnetic Activity, and Climate Change

    Johnson, Robert W

    2009-01-01

    The continuous wavelet transform is adapted to account for signal truncation through renormalization and by modifying the shape of the analyzing window. Comparison is made of the instant and integrated wavelet power with previous algorithms. The edge adapted and renormalized admissible wavelet transforms are used to estimate the level of solar magnetic activity from the sunspot record. The solar activity is compared to Oerlemans' temperature reconstruction and to the Central England Temperatu...

  2. Disruption of nuclear factor (erythroid-derived-2)-like 2 antioxidant signaling: a mechanism for impaired activation of stem cells and delayed regeneration of skeletal muscle.

    Shelar, Sandeep Balu; Narasimhan, Madhusudhanan; Shanmugam, Gobinath; Litovsky, Silvio Hector; Gounder, Sellamuthu S; Karan, Goutam; Arulvasu, Cinnasamy; Kensler, Thomas W; Hoidal, John R; Darley-Usmar, Victor M; Rajasekaran, Namakkal S

    2016-05-01

    Recently we have reported that age-dependent decline in antioxidant levels accelerated apoptosis and skeletal muscle degeneration. Here, we demonstrate genetic ablation of the master cytoprotective transcription factor, nuclear factor (erythroid-derived-2)-like 2 (Nrf2), aggravates cardiotoxin (CTX)-induced tibialis anterior (TA) muscle damage. Disruption of Nrf2 signaling sustained the CTX-induced burden of reactive oxygen species together with compromised expression of antioxidant genes and proteins. Transcript/protein expression of phenotypic markers of muscle differentiation, namely paired box 7 (satellite cell) and early myogenic differentiation and terminal differentiation (myogenin and myosin heavy chain 2) were increased on d 2 and 4 postinjury but later returned to baseline levels on d 8 and 15 in wild-type (WT) mice. In contrast, these responses were persistently augmented in Nrf2-null mice suggesting that regulation of the regeneration-related signaling mechanisms require Nrf2 for normal functioning. Furthermore, Nrf2-null mice displayed slower regeneration marked by dysregulation of embryonic myosin heavy chain temporal expression. Histologic observations illustrated that Nrf2-null mice displayed smaller, immature TA muscle fibers compared with WT counterparts on d 15 after CTX injury. Improvement in TA muscle morphology and gain in muscle mass evident in the WT mice was not noticeable in the Nrf2-null animals. Taken together these data show that the satellite cell activation, proliferation, and differentiation requires a functional Nrf2 system for effective healing following injury.-Shelar, S. B., Narasimhan, M., Shanmugam, G., Litovsky, S. H., Gounder, S. S., Karan, G., Arulvasu, C., Kensler, T. W., Hoidal, J. R., Darley-Usmar, V. M., Rajasekaran, N. S. Disruption of nuclear factor (erythroid-derived-2)-like 2 antioxidant signaling: a mechanism for impaired activation of stem cells and delayed regeneration of skeletal muscle. PMID:26839378

  3. Solar Magnetism and the Activity Telescope at HSOS

    Hong-Qi Zhang; Ya-Nan Wang; Qi-Qian Hu; Jun-Sun Xue; Hai-Tian Lu; Hou-Kun Ni; Han-Liang Chen; Xiao-Jun Zhou; Qing-Sheng Zhu; Lü-Jun Yuan; Yong Zhu; Dong-Guang Wang; Yuan-Yong Deng; Ke-Liang Hu; Jiang-Tao Su; Jia-Ben Lin; Gang-Hua Lin; Shi-Mo Yang; Wei-Jun Mao

    2007-01-01

    A new solar telescope system is described, which has been operating at Huairou Solar Observing Station (HSOS), National Astronomical Observatories, Chinese Academy of Sciences (CAS), since the end of 2005. This instrument, the Solar Magnetism and Activity Telescope (SMAT), comprises two telescopes which respectively make measurements of full solar disk vector magnetic field and Hα observation. The core of the full solar disk video vector magnetograph is a birefringent filter with 0.1(A) bandpass, installed in the tele-centric optical system of the telescope. We present some preliminary observational results of the full solar disk vector magnetograms and Hα filtergrams obtained with this telescope system.

  4. Bone regeneration with active angiogenesis by basic fibroblast growth factor gene transfected mesenchymal stem cells seeded on porous β-TCP ceramic scaffolds

    Large segmental bone defect repair remains a clinical and scientific challenge with increasing interest focused on combining gene transfer with tissue engineering techniques. Basic fibroblast growth factor (bFGF) is one of the most prominent osteogenic growth factors that has the potential to accelerate bone healing by promoting the proliferation and differentiation of mesenchymal stem cells (MSCs) and the regeneration of capillary vasculature. However, the short biological half-lives of growth factors may impose severe restraints on their clinical usefulness. Gene-based delivery systems provide a better way of achieving a sustained high concentration of growth factors locally in the defect and delivering a more biologically active product than that achieved by exogenous application of recombinant proteins. The objective of this experimental study was to investigate whether the bFGF gene modified MSCs could enhance the repair of large segmental bone defects. The pcDNA3-bFGF gene transfected MSCs were seeded on biodegradable porous β tricalcium phosphate (β-TCP) ceramics and allografted into the 15 mm critical-sized segmental bone defects in the radius of 18 New Zealand White rabbits. The pcDNA3 vector gene transfected MSCs were taken as the control. The follow-up times were 2, 4, 6, 8, 10 and 12 weeks. Scanning electron microscopic, roentgenographic, histologic and immunohistological studies were used to assess angiogenesis and bone regeneration. In vitro, the proliferation and differentiation of bFGF gene transfected MSCs were more active than that of the control groups. In vivo, significantly more new bone formation accompanied by abundant active capillary regeneration was observed in pores of the ceramics loaded with bFGF gene transfected MSCs, compared with control groups. Transfer of gene encoding bFGF to MSCs increases their osteogenic properties by enhancing capillary regeneration, thus providing a rich blood supply for new bone formation. This new b

  5. Chromospheric magnetic fields of an active region filament

    Xu, Z.; Solanki, S.; Lagg, A.

    2012-06-01

    Vector magnetic fields of an active region filament are co-spatially and co-temporally mapped in photosphere and upper chromosphere, by using spectro-polarimetric observations made by Tenerife Infrared Polarimeter (TIP II) at the German Vacuum Tower Telescope (VTT). A Zeeman-based ME inversion is performed on the full Stokes vectors of both the photospheric Si I 1082.7 nm and the chromospheric He I 1083.0 nm lines. We found that the strong magnetic fields, with the field strength of 600 - 800 G in the He I line formation height, are not uncommon among AR filaments. But such strong magnetic field is not always found in AR filaments.

  6. Magnetic field structures in active compact radio sources

    The analysis of simultaneous multifrequency linear polarimetry data between 1.4 GHz and 90 GHz for about 20 active, compact radio sources at six epochs from 1977 December 10 1980 July is presented. In addition, monthly 8 Ghz polarization data on the same sources were examined. The general polarization characteristics of these sources can be well described in terms of magnetic fields which are largely turbulent and slightly anisotropic. The magnetic field symmetry axes are generally aligned with the source structural axes on the milli-arcsecond scale (OJ 287 is a notable exception.) Monte Carlo calculations indicate that observed polarization variations and in particular rotator polarization events can be produced in this model as a consequence of random walks generated through evolution of the turbulent magnetic field. 43 references

  7. Plant regeneration: cellular origins and molecular mechanisms.

    Ikeuchi, Momoko; Ogawa, Yoichi; Iwase, Akira; Sugimoto, Keiko

    2016-05-01

    Compared with animals, plants generally possess a high degree of developmental plasticity and display various types of tissue or organ regeneration. This regenerative capacity can be enhanced by exogenously supplied plant hormones in vitro, wherein the balance between auxin and cytokinin determines the developmental fate of regenerating organs. Accumulating evidence suggests that some forms of plant regeneration involve reprogramming of differentiated somatic cells, whereas others are induced through the activation of relatively undifferentiated cells in somatic tissues. We summarize the current understanding of how plants control various types of regeneration and discuss how developmental and environmental constraints influence these regulatory mechanisms. PMID:27143753

  8. Detailed design of a resonantly enhanced axion-photon regeneration experiment

    A resonantly enhanced photon-regeneration experiment to search for the axion or axionlike particles is described. This experiment is a shining light through walls study, where photons traveling through a strong magnetic field are (in part) converted to axions; the axions can pass through an opaque wall and convert (in part) back to photons in a second region of strong magnetic field. The photon regeneration is enhanced by employing matched Fabry-Perot optical cavities, with one cavity within the axion generation magnet and the second within the photon-regeneration magnet. Compared to simple single-pass photon regeneration, this technique would result in a gain of (F/π)2, where F is the finesse of each cavity. This gain could feasibly be as high as 1010, corresponding to an improvement in the sensitivity to the axion-photon coupling, gaγγ, of order (F/π)1/2∼300. This improvement would enable, for the first time, a purely laboratory experiment to probe axion-photon couplings at a level competitive with, or superior to, limits from stellar evolution or solar axion searches. This report gives a detailed discussion of the scheme for actively controlling the two Fabry-Perot cavities and the laser frequencies, and describes the heterodyne signal detection system, with limits ultimately imposed by shot noise.

  9. The Magnetic Classification of Solar Active Regions 1992 - 2015

    Jaeggli, Sarah A.; Norton, Aimee A.

    2016-01-01

    The purpose of this letter is to address a blind-spot in our knowledge of solar active region statistics. To the best of our knowledge there are no published results showing the variation of the Mount Wilson magnetic classifications as a function of solar cycle based on modern observations. We show statistics for all active regions reported in the daily Solar Region Summary from 1992 January 1 to 2015 December 31. We find that the $\\alpha$ and $\\beta$ class active regions (including all sub-g...

  10. Regeneration of Activated Carbon with Toluene by Microwave Radiation%微波辐照再生载甲苯活性炭

    宁平; 田森林; 等

    2001-01-01

    本文提出了一种运用微波辐照再生吸附有甲苯废气活性炭的新再生方法。通过正交试验,探讨了活性炭在微波辐照条件下脱附率与活性炭量、微波功率、载气线速度及再生时间等因素的关系;得出了再生的优化条件;测定了解吸速率曲线;对影响活性炭损耗的各因素进行了分析;并对再生后甲苯的冷凝回收法进行了探索。%This paper presents a new method of regenerat ing activated carbon with toluene by microwave radiation.By orthogonal experimen t,the connections between ratio of deadsorption and influencing factors:quantity act ivated carbon,power of microwave,surface speed of carrier gas and regeneration t ime are staudied.Optimized conditions of regeneration are summarized.Velocity c urve of regene ration is determined.Factors,which affect Activated carbon ullage,are analyzed.R ecovering process of toluene is researched also.

  11. FINE MAGNETIC FEATURES AND CHIRALITY IN SOLAR ACTIVE REGION NOAA 10930

    In this paper, we present fine magnetic features near the magnetic inversion line in the solar active region NOAA 10930. The high-resolution vector magnetograms obtained by Hinode allow detailed analyses around magnetic fibrils in the active region. The analyses are based on the fact that the electric current density can be divided into two components: the shear component caused by the magnetic inhomogeneity and the twist component caused by the magnetic field twist. The relationships between magnetic field, electric current density, and its two components are examined. It is found that the individual magnetic fibrils are dominated by the current density component caused by the magnetic inhomogeneity, while the large-scale magnetic region is generally dominated by the electric current component associated with the magnetic twist. The microstructure of the magnetic field in the solar atmosphere is far from the force-free field. The current mainly flows around the magnetic flux fibrils in the active regions.

  12. Phenyl-functionalized magnetic palm-based powdered activated carbon for the effective removal of selected pharmaceutical and endocrine-disruptive compounds.

    Wong, Kien Tiek; Yoon, Yeomin; Snyder, Shane A; Jang, Min

    2016-06-01

    Triethoxyphenylsilane (TEPS)-functionalized magnetic palm-based powdered activated carbon (MPPAC-TEPS) was prepared and characterized using various spectroscopic methods, and then tested for the removal of bisphenol A, carbamazepine, ibuprofen and clofibric acid. Magnetite film on MPPAC-TEPS was homogeneously coated on the outer surface of palm-based powdered activated carbon (PPAC) through a hydrothermal co-precipitation technique. Followed by silanization of phenyl-functionalized organosilane on MPPAC's magnetic film. As results, micro/mesopore surface area and volume increased without significant pore clogging and iron (Fe) dissolution under the acidic conditions was greatly decreased. The unique structural and chemical features of MPPAC-TEPS were found to be the main reasons for the enhanced adsorption rates and removal capacities of POPs. The presence of electrolytes and different pH values greatly affected the sorption efficiencies. The dominant sorption mechanism of POPs by MPPAC-TEPS was determined to be π-π interaction (physisorption), based on thermodynamic (ΔG°) and differential scanning calorimetry (DSC). Thermal regeneration at a low temperature (350 °C) was an effective method to desorb the retained POPs and enabled to reactivate MPPAC-TEPS with sustained sorption rates and capacities, whereas PPAC was largely exhausted. As a new type of sorbent for POPs, MPPAC-TEPS has operational advantages, such as magnetic separation and stable regeneration. PMID:26963238

  13. Glutathione transferases P1/P2 regulate the timing of signaling pathway activations and cell cycle progression during mouse liver regeneration.

    Pajaud, J; Ribault, C; Ben Mosbah, I; Rauch, C; Henderson, C; Bellaud, P; Aninat, C; Loyer, P; Morel, F; Corlu, A

    2015-01-01

    Glutathione transferases (GST) are phase II enzymes catalyzing the detoxification of endogenous noxious compounds and xenobiotics. They also regulate phosphorylation activities of MAPKinases in a catalytic-independent manner. Previous studies have demonstrated the regulation of JNK-dependent pathway by GSTP1/2. Considering the crucial role of JNK in the early steps of the hepatocyte cell cycle, we sought to determine whether GSTP1/2 were essential for hepatocyte proliferation following partial hepatectomy (PH). Using a conventional double knockout mouse model for the Gstp1 and Gstp2 genes, we found that the lack of GSTP1/P2 reduced the rate of DNA replication and mitotic index during the first wave of hepatocyte proliferation. The lowered proliferation was associated with the decrease in TNFalpha and IL-6 plasma concentrations, reduced hepatic HGF expression and delayed and/or altered activation of STAT3, JNK and ERK1/2 signaling pathways. In addition, the expression and/or activation of cell cycle regulators such as Cyclin D1, CDK4, E2F1 and MCM7 was postponed demonstrating that the absence of GSTP1/2 delayed the entry into and progression through the G1 phase of the cell cycle and impaired the synchrony of proliferation in hepatocytes following PH. Furthermore, while JNK and its downstream targets c-Jun and ATF2 were activated during the early steps of the liver regeneration in wild-type animals, the constitutively active JNK found in the quiescent liver of Gstp1/2 knockout mice underwent a decrease in its activity after PH. Transient induction of antioxidant enzymes and nitric oxide synthase were also delayed or repressed during the regenerative response. Altogether our results demonstrate that GSTP1/2 are a critical regulators of hepatocyte proliferation in the initial phases of liver regeneration. PMID:25590808

  14. Towards age/rotation/magnetic activity relation with seismology

    Mathur Savita

    2015-01-01

    Full Text Available The knowledge of stellar ages directly impacts the characterization of a planetary system as it puts strong constraints on the moment when the system was born. Unfortunately, the determination of precise stellar ages is a very difficult task. Different methods can be used to do so (based on isochrones or chemical element abundances but they usually provide large uncertainties. During its evolution a star goes through processes leading to loss of angular momentum but also changes in its magnetic activity. Building rotation, magnetic, age relations would be an asset to infer stellar ages model independently. Several attempts to build empirical relations between rotation and age (namely gyrochronology were made with a focus on cluster stars where the age determination is easier and for young stars on the main sequence. For field stars, we can now take advantage of high-precision photometric observations where we can perform asteroseismic analyses to improve the accuracy of stellar ages. Furthermore, the variability in the light curves allow us to put strong constraints on the stellar rotation and magnetic activity. By combining these precise measurements, we are on the way of understanding and improving relations between magnetic activity, rotation, and age, in particular at different stages of stellar evolution. I will review the status on gyrochronology relationships based on observations of young cluster stars. Then I will focus on solar-like stars and describe the inferences on stellar ages, rotation, and magnetism that can be provided by high-quality photometric observations such as the ones of the Kepler mission, in particular through asteroseismic analyses.

  15. MAGNETIC FLUX PARADIGM FOR RADIO LOUDNESS OF ACTIVE GALACTIC NUCLEI

    We argue that the magnetic flux threading the black hole (BH), rather than BH spin or Eddington ratio, is the dominant factor in launching powerful jets and thus determining the radio loudness of active galactic nuclei (AGNs). Most AGNs are radio quiet because the thin accretion disks that feed them are inefficient in depositing magnetic flux close to the BH. Flux accumulation is more likely to occur during a hot accretion (or thick disk) phase, and we argue that radio-loud quasars and strong emission-line radio galaxies occur only when a massive, cold accretion event follows an episode of hot accretion. Such an event might be triggered by the merger of a giant elliptical galaxy with a disk galaxy. This picture supports the idea that flux accumulation can lead to the formation of a so-called magnetically choked accretion flow. The large observed range in radio loudness reflects not only the magnitude of the flux pressed against the BH, but also the decrease in UV flux from the disk, due to its disruption by the ''magnetosphere'' associated with the accumulated flux. While the strongest jets result from the secular accumulation of flux, moderate jet activity can also be triggered by fluctuations in the magnetic flux deposited by turbulent, hot inner regions of otherwise thin accretion disks, or by the dissipation of turbulent fields in accretion disk coronae. These processes could be responsible for jet production in Seyferts and low-luminosity AGNs, as well as jets associated with X-ray binaries.

  16. Host cell and expression engineering for development of an E. coli ketoreductase catalyst: Enhancement of formate dehydrogenase activity for regeneration of NADH

    Mädje Katharina

    2012-01-01

    Full Text Available Abstract Background Enzymatic NADH or NADPH-dependent reduction is a widely applied approach for the synthesis of optically active organic compounds. The overall biocatalytic conversion usually involves in situ regeneration of the expensive NAD(PH. Oxidation of formate to carbon dioxide, catalyzed by formate dehydrogenase (EC 1.2.1.2; FDH, presents an almost ideal process solution for coenzyme regeneration that has been well established for NADH. Because isolated FDH is relatively unstable under a range of process conditions, whole cells often constitute the preferred form of the biocatalyst, combining the advantage of enzyme protection in the cellular environment with ease of enzyme production. However, the most prominent FDH used in biotransformations, the enzyme from the yeast Candida boidinii, is usually expressed in limiting amounts of activity in the prime host for whole cell biocatalysis, Escherichia coli. We therefore performed expression engineering with the aim of enhancing FDH activity in an E. coli ketoreductase catalyst. The benefit resulting from improved NADH regeneration capacity is demonstrated in two transformations of technological relevance: xylose conversion into xylitol, and synthesis of (S-1-(2-chlorophenylethanol from o-chloroacetophenone. Results As compared to individual expression of C. boidinii FDH in E. coli BL21 (DE3 that gave an intracellular enzyme activity of 400 units/gCDW, co-expression of the FDH with the ketoreductase (Candida tenuis xylose reductase; XR resulted in a substantial decline in FDH activity. The remaining FDH activity of only 85 U/gCDW was strongly limiting the overall catalytic activity of the whole cell system. Combined effects from increase in FDH gene copy number, supply of rare tRNAs in a Rosetta strain of E. coli, dampened expression of the ketoreductase, and induction at low temperature (18°C brought up the FDH activity threefold to a level of 250 U/gCDW while reducing the XR activity by

  17. The development of an axial active magnetic bearing / R. Gouws

    Gouws, Rupert

    2004-01-01

    In this dissertation, the author presents the operation and development of active magnetic bearings (AMBs) , with specific focus on axial M s . The project objective is the development of an axial AMB system. The electromagnetic design, inductive sensor design, dSpace controller model design and actuating amplifier design are aspects discussed in this dissertation. The physical model constitutes two electromagnets positioned above and beneath a 2 kg steel disc with an air gap o...

  18. Condition monitoring of active magnetic bearing systems / Rupert Gouws

    Gouws, Rupert

    2007-01-01

    In this thesis, the author contextualises condition monitoring of active magnetic bearing (AMB) systems and proposes the real-time condition monitoring of AMB systems. Three real-time fault detection, diagnosis, correction and identification schemes for vibration forces on the rotor of a rotational AMB system are proposed. Two AMB systems were used to conduct this research. The one was a fully suspended 250 kW water cooling AMB pump from which historical fault data was obtained and the oth...

  19. Repetitive transcranial magnetic stimulation activates specific regions in rat brain

    Ji, Ru-Rong; Schlaepfer, Thomas E.; Aizenman, Carlos D.; Epstein, Charles M.; Qiu, Dike; Huang, Justin C.; Rupp, Fabio

    1998-01-01

    Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive technique to induce electric currents in the brain. Although rTMS is being evaluated as a possible alternative to electroconvulsive therapy for the treatment of refractory depression, little is known about the pattern of activation induced in the brain by rTMS. We have compared immediate early gene expression in rat brain after rTMS and electroconvulsive stimulation, a well-established animal model for electroconvulsive ther...

  20. On the filament motion in magnetic field of active regions

    The study of filament motion in magnetic field of active regions is fulfiled. Filament movement can possibly be presented as a drift in the crossed fields, but there exist fast movements that cannot be described as a drift. For very fast motion, with acceleration greater than that of free fall, it is sometimes necessary to assume, that the motion is carried out due to the filament's own electric current. A model, describing filament motion data, given by Mouradian M. is presented

  1. Fault Diagnosis in a Centrifugal Pump Using Active Magnetic Bearings

    Nordmann Rainer; Aenis Martin

    2004-01-01

    The number of rotors running in active magnetic bearings (AMBs) has increased over the last few years. These systems offer a great variety of advantages compared to conventional systems. The aim of this article is to use the AMBs together with a developed built-in software for identification, fault detection, and diagnosis in a centrifugal pump. A single-stage pump representing the turbomachines is investigated. During full operation of the pump, the AMBs are used as actuators to generate def...

  2. On the Magnetic Field Strength of Active Region Filaments

    Kuckein, C; Pillet, V Martinez; Casini, R; Sainz, R Manso; Shimizu, T

    2009-01-01

    We study the vector magnetic field of a filament observed over a compact Active Region Neutral Line. Spectropolarimetric data acquired with TIP-II (VTT, Tenerife, Spain) of the 10830 \\AA spectral region provide full Stokes vectors which were analyzed using three different methods: magnetograph analysis, Milne-Eddington inversions and PCA-based atomic polarization inversions. The inferred magnetic field strengths in the filament are of the order of 600 - 700 G by all these three methods. Longitudinal fields are found in the range of 100 - 200 G whereas the transverse components become dominant, with fields as large as 500 - 600 G. We find strong transverse fields near the Neutral Line also at photospheric levels. Our analysis indicates that strong (higher than 500 G, but below kG) transverse magnetic fields are present in Active Region filaments. This corresponds to the highest field strengths reliably measured in these structures. The profiles of the Helium 10830 \\AA lines observed in this Active Region filam...

  3. Graphene Oxide-Copper Nanocomposite-Coated Porous CaP Scaffold for Vascularized Bone Regeneration via Activation of Hif-1α.

    Zhang, Wenjie; Chang, Qing; Xu, Ling; Li, Guanglong; Yang, Guangzheng; Ding, Xun; Wang, Xiansong; Cui, Daxiang; Jiang, Xinquan

    2016-06-01

    Graphene has been studied for its in vitro osteoinductive capacity. However, the in vivo bone repair effects of graphene-based scaffolds remain unknown. The aqueous soluble graphene oxide-copper nanocomposites (GO-Cu) are fabricated, which are used to coat porous calcium phosphate (CaP) scaffolds for vascularized bone regeneration. The GO-Cu nanocomposites, containing crystallized CuO/Cu2 O nanoparticles of ≈30 nm diameters, distribute uniformly on the surfaces of the porous scaffolds and maintain a long-term release of Cu ions. In vitro, the GO-Cu coating enhances the adhesion and osteogenic differentiation of rat bone marrow stem cells (BMSCs). It is also found that by activating the Erk1/2 signaling pathway, the GO-Cu nanocomposites upregulate the expression of Hif-1α in BMSCs, resulting in the secretion of VEGF and BMP-2 proteins. When transplanted into rat with critical-sized calvarial defects, the GO-Cu-coated calcium phosphate cement (CPC) scaffolds (CPC/GO-Cu) significantly promote angiogenesis and osteogenesis. Moreover, it is observed via histological sections that the GO-Cu nanocomposites are phagocytosed by multinucleated giant cells. The results suggest that GO-Cu nanocomposite coatings can be utilized as an attractive strategy for vascularized bone regeneration. PMID:26945787

  4. Edge Adapted Wavelets, Solar Magnetic Activity, and Climate Change

    Johnson, Robert W

    2009-01-01

    The continuous wavelet transform is adapted to account for signal truncation through renormalization and by modifying the shape of the analyzing window. Comparison is made of the instant and integrated wavelet power with previous algorithms. The edge adapted and renormalized admissible wavelet transforms are used to estimate the level of solar magnetic activity from the sunspot record. The solar activity is compared to Oerlemans' temperature reconstruction and to the Central England Temperature record. A correlation is seen for years between 1610 and 1990, followed by a strong deviation as the recently observed temperature increases.

  5. Development of a He{sup 3}−He{sup 4} sub Kelvin active magnetic regenerative refrigerator (AMRR) with no moving parts

    Jahromi, A. E. [Ph.D. student, University of Wisconsin -1500 Engineering Drive, 1335 ERB, Madison, WI, 53706 (United States); Miller, F. K. [Assistant Professor of Mechanical Engineering, University of Wisconsin - 1500 Engineering Drive, 1341 ERB Madison, WI 53706 (United States)

    2014-01-29

    Current state of the art particle and photon detectors such as Transition Edge Sensors (TES) and Microwave Kinetic Inductance Detectors (MKID) use large arrays of sensors or detectors for space science missions. As the size of these space science detectors increases, future astrophysics missions will require sub-Kelvin cooling over larger areas. This leads to not only increased cooling power requirements, but also a requirement for distributed sub-Kelvin cooling. We propose an active Magnetic Regenerative Refrigerator (AMRR) that uses a Superfluid Magnetic Pump (SMP) to circulate liquid He{sup 3}−He{sup 4} through a magnetic regenerator to provide the necessary cooling at sub-Kelvin temperatures. Such system will be capable of distributing the cooling load to a relatively large array of objects. One advantage of using a fluid for heat transfer in such systems is to isolate components such as the superconducting magnets from detectors that are sensitive to magnetic fields. Another advantage of the proposed tandem AMRR is that it does not need Gas Gap Heat Switches (GGHS) to transfer heat during various stages of the magnetic cooling. Our proposed system consists of four superconducting magnets, one superleak, and three heat exchangers. It will operate continuously with no moving parts and it will be capable of providing the necessary cooling at sub-Kelvin temperatures for future space science applications.

  6. The Relationship between Magnetic Gradient and Magnetic Shear in Five Super Active Regions Producing Great Flares

    Hai-Min Wang; Hui Song; Ju Jing; Vasyl Yurchyshyn; Yuan-Yong Deng; Hong-Qi Zhang; David Falconer; Jing Li

    2006-01-01

    We study the magnetic structure of five well-known active regions that produced great flares (X5 or larger). The six flares under investigation are the X12 flare on 1991 June 9in AR 6659, the X5.7 flare on 2000 July 14 in AR 9077, the X5.6 flare on 2001 April 6 in AR 9415, the X5.3 flare on 2001 August 25 in AR 9591, the X17 flare on 2003 October 28 and the X10 flare on 2003 October 29, both in AR 10486. The last five events had corresponding LASCO observations and were all associated with Halo CMEs. We analyzed vector magnetograms from Big Bear Solar Observatory, Huairou Solar Observing Station, Marshall Space Flight Center and Mees Solar Observatory. In particular, we studied the magnetic gradient derived from line-of-sight magnetograms and magnetic shear derived from vector magnetograms, and found an apparent correlation between these two parameters at a level of about 90%. We found that the magnetic gradient could be a better proxy than the shear for predicting where a major flare might occur: all six flares occurred in neutral lines with maximum gradient. The mean gradient of the flaring neutral lines ranges from 0.14 to 0.50 G km-1, 2.3to 8 times the average value for all the neutral lines in the active regions. If we use magnetic shear as the proxy, the flaring neutral line in at least one, possibly two, of the six events would be mis-identified.

  7. MAGNETIC ACTIVITY CYCLES IN THE EXOPLANET HOST STAR {epsilon} ERIDANI

    Metcalfe, T. S.; Mathur, S. [Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 (United States); Buccino, A. P.; Mauas, P. J. D.; Petrucci, R. [Instituto de Astronomia y Fisica del Espacio (CONICET), C.C. 67 Sucursal 28, C1428EHA-Buenos Aires (Argentina); Brown, B. P. [Department of Astronomy and Center for Magnetic Self-Organization, University of Wisconsin, Madison, WI 53706-1582 (United States); Soderblom, D. R. [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Henry, T. J. [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30302 (United States); Hall, J. C. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Basu, S. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States)

    2013-02-01

    The active K2 dwarf {epsilon} Eri has been extensively characterized both as a young solar analog and more recently as an exoplanet host star. As one of the nearest and brightest stars in the sky, it provides an unparalleled opportunity to constrain stellar dynamo theory beyond the Sun. We confirm and document the 3-year magnetic activity cycle in {epsilon} Eri originally reported by Hatzes and coworkers, and we examine the archival data from previous observations spanning 45 years. The data show coexisting 3-year and 13-year periods leading into a broad activity minimum that resembles a Maunder minimum-like state, followed by the resurgence of a coherent 3-year cycle. The nearly continuous activity record suggests the simultaneous operation of two stellar dynamos with cycle periods of 2.95 {+-} 0.03 years and 12.7 {+-} 0.3 years, which, by analogy with the solar case, suggests a revised identification of the dynamo mechanisms that are responsible for the so-called 'active' and 'inactive' sequences as proposed by Boehm-Vitense. Finally, based on the observed properties of {epsilon} Eri, we argue that the rotational history of the Sun is what makes it an outlier in the context of magnetic cycles observed in other stars (as also suggested by its Li depletion), and that a Jovian-mass companion cannot be the universal explanation for the solar peculiarities.

  8. Bone morphogenetic proteins: Periodontal regeneration

    Subramaniam M Rao

    2013-01-01

    Full Text Available Periodontitis is an infectious inflammatory disease that results in attachment loss and bone loss. Regeneration of the periodontal tissues entails de novo formation of cementum, periodontal ligament, and alveolar bone. Several different approaches are currently being explored to achieve complete, reliable, and reproducible regeneration of periodontal tissues. The therapeutic management of new bone formation is one of the key issues in successful periodontal regeneration. Bone morphogenetic proteins form a unique group of proteins within the transforming growth factor superfamily of genes and have a vital role in the regulation in the bone induction and maintenance. The activity of bone morphogenetic proteins was first identified in the 1960s, but the proteins responsible for bone induction were unknown until the purification and cloning of human bone morphogenetic proteins in the 1980s, because of their osteoinductive potential. Bone morphogenetic proteins have gained a lot of interest as therapeutic agents for treating periodontal defects. A systematic search for data related to the use of bone morphogenetic proteins for the regeneration of periodontal defects was performed to recognize studies on animals and human (PUBMED, MEDLINE, COCHRANE, and Google search. All the studies included showed noticeable regeneration of periodontal tissues with the use of BMP.

  9. Developments in the field of active magnetic bearings at EDF

    The studies carried out by EDF concerning the evaluation of the active magnetic bearing technology for their possible application to rotating machinery in electrical plants, and especially the 900 MW ''CP2'' turbogenerators which appear to have very little damping and vibrate noticeably during transients. Using a 4 tons test bench, the good quality of simulation applied to both permanent and transient conditions have been verified. Then, using a 10 tons test bench, the dimensioning concerns of the CP2 application were more precisely evaluated. It has been especially demonstrated that the accessible levels of force and damping were compatible with the application constraints. In a final 30 tons project, some innovative technological components have been used and the benefits from an optimization of the design of the magnetic parameters were determined. Specifications for a full-scale implementation have been therefore defined to enable the manufacturer to make a commercial offer. After a disappointing analysis of the offer, CP2 computations and studies were stopped but subsidiary studies were conducted: estimation of the damage risk under alternative bending of the CP2 rotors during their lifetime, prospective analysis of other possible applications of active magnetic bearings in power plants, development of a new vibratory test method through electromagnetic excitation. 5 figs., 6 refs

  10. Active split-ring metamaterial slabs for magnetic resonance imaging

    Lopez, Marcos A; Freire, Manuel J; Behr, Volker C; Jakob, Peter M; Marques, Ricardo

    2011-01-01

    In this work, it is analyzed the ability of split-ring metamaterial slabs with zero/high permeability to reject/confine the radiofrequency magnetic field in magnetic resonance imaging systems. Using an homogenization procedure, split-ring slabs have been designed and fabricated to work in a 1.5T system. Active elements consisting of pairs of crossed diodes are inserted in the split-rings. With these elements, the permeability of the slabs can be automatically switched between a unity value when interacting with the strong excitation field of the transmitting body coil, and zero or high values when interacting with the weak field produced by protons in tissue. Experiments are shown for different configurations where these slabs can help to locally increase the signal-to-noise-ratio.

  11. Towards age/rotation/magnetic activity relation with seismology

    Mathur, Savita

    2015-01-01

    The knowledge of stellar ages directly impacts the characterization of a planetary system as it puts strong constraints on the moment when the system was born. Unfortunately, the determination of precise stellar ages is a very difficult task. Different methods can be used to do so (based on isochrones or chemical element abundances) but they usually provide large uncertainties. During its evolution a star goes through processes leading to loss of angular momentum but also changes in its magnetic activity. Building rotation, magnetic, age relations would be an asset to infer stellar ages model independently. Several attempts to build empirical relations between rotation and age (namely gyrochronology) were made with a focus on cluster stars where the age determination is easier and for young stars on the main sequence. For field stars, we can now take advantage of high-precision photometric observations where we can perform asteroseismic analyses to improve the accuracy of stellar ages. Furthermore, the variab...

  12. Optimisation Of An Integrated Planar Magnetic For Active Antenna Panels

    Strixner, E.; Godzik, S.; Drechsler, E., , Dr.

    2011-10-01

    The envisaged German Space Missions HRWS and TerraSAR-X follow-on have triggered the development of a new generation of low voltage DC power supplies for active antennas at Astrium GmbH. The basic approachis tointegrate all power, digital, RF electronics and RF radiators required for one antenna tile into one common unit. Due to the high number of electronic boxes needed for one antenna it is essential to optimise cost, volume, efficiency and weight. The development of an integrated planar magnetic for power conversion is one contribution to this overall optimisation process. The focus of this presentation is the development of an integrated planar magnetic used for a half-bridge forward converter with secondary side synchronous current doubler. The converter is supplied from a 100 V power bus and delivers a total average output power of 280W for the drain supply of the pulsed RF power stages.

  13. Activation of sweeping magnets in Tevatron II standardized target piles

    As designs of the primary targeting schemes for the new Tevatron II slow spill beams progress, it is becoming clear that a standardized form for these schemes is emerging. The general form consists of a production target (usually about 30 cm of beryllium having a diameter from 0.64 to 1.27 cm) followed by from one to three of the new Tevatron II H frame magnets recently developed by D. Eartly. These magnets sweep the unused primary proton beam onto a massive steel beam dump containing a core of material capable of dispersing the energy of the beam along with a hole for transmitting the secondary beam desired at experimental targets. Typical primary proton intensities at such production targets are planned to be in the range of 3 x 1012 to 5 x 1012 protons per spill. If one assumes such operation during a run of 4000 hours per year, 60 spills per hour, the integrated beam is seen to be approximately 1 x 1018 per year targetted at a rate of 7/0 x 1010 protons/sec during the run. It is clear, from experience, that such beam intensities require that the water used to cool the beam dump must be in a closed loop system both to protect personnel during operations from the external radiation exposure rate due to short lived radionuclides (e.g., 11C and 7Be) and to protect against release of significant activities of tritium into surface waters. It is not certain that a closed loop system is required for the sweeping magnets. This TM reports on a calculation designed to evaluate this potential problem, the expected dose rates external to such magnets, and the total activity which will be contained in them and the target

  14. MAGNETIC FLUX PARADIGM FOR RADIO LOUDNESS OF ACTIVE GALACTIC NUCLEI

    Sikora, Marek [Copernicus Astronomical Center, Polish Academy of Sciences, ul. Bartycka 18, 00-716 Warsaw (Poland); Begelman, Mitchell C., E-mail: sikora@camk.edu.pl, E-mail: mitch@jila.colorado.edu [JILA, University of Colorado and National Institute of Standards and Technology, 440 UCB, Boulder, CO 80309 (United States)

    2013-02-20

    We argue that the magnetic flux threading the black hole (BH), rather than BH spin or Eddington ratio, is the dominant factor in launching powerful jets and thus determining the radio loudness of active galactic nuclei (AGNs). Most AGNs are radio quiet because the thin accretion disks that feed them are inefficient in depositing magnetic flux close to the BH. Flux accumulation is more likely to occur during a hot accretion (or thick disk) phase, and we argue that radio-loud quasars and strong emission-line radio galaxies occur only when a massive, cold accretion event follows an episode of hot accretion. Such an event might be triggered by the merger of a giant elliptical galaxy with a disk galaxy. This picture supports the idea that flux accumulation can lead to the formation of a so-called magnetically choked accretion flow. The large observed range in radio loudness reflects not only the magnitude of the flux pressed against the BH, but also the decrease in UV flux from the disk, due to its disruption by the ''magnetosphere'' associated with the accumulated flux. While the strongest jets result from the secular accumulation of flux, moderate jet activity can also be triggered by fluctuations in the magnetic flux deposited by turbulent, hot inner regions of otherwise thin accretion disks, or by the dissipation of turbulent fields in accretion disk coronae. These processes could be responsible for jet production in Seyferts and low-luminosity AGNs, as well as jets associated with X-ray binaries.

  15. Optimization of magnetic powdered activated carbon for aqueous Hg(II) removal and magnetic recovery.

    Faulconer, Emily K; von Reitzenstein, Natalia V Hoogesteijn; Mazyck, David W

    2012-01-15

    Activated carbon is known to adsorb aqueous Hg(II). MPAC (magnetic powdered activated carbon) has the potential to remove aqueous Hg to less than 0.2 μg/L while being magnetically recoverable. Magnetic recapture allows simple sorbent separation from the waste stream while an isolated waste potentially allows for mercury recycling. MPAC Hg-removal performance is verified by mercury mass balance, calculated by quantifying adsorbed, volatilized, and residual aqueous mercury. The batch reactor contained a sealed mercury-carbon contact chamber with mixing and constant N(2) (g) headspace flow to an oxidizing trap. Mercury adsorption was performed using spiked ultrapure water (100 μg/L Hg). Mercury concentrations were obtained using EPA method 245.1 and cold vapor atomic absorption spectroscopy. MPAC synthesis was optimized for Hg removal and sorbent recovery according to the variables: C:Fe, thermal oxidation temperature and time. The 3:1 C:Fe preserved most of the original sorbent surface area. As indicated by XRD patterns, thermal oxidation reduced the amorphous characteristic of the iron oxides but did not improve sorbent recovery and damaged porosity at higher oxidation temperatures. Therefore, the optimal synthesis variables, 3:1 C:Fe mass ratio without thermal oxidation, which can achieve 92.5% (± 8.3%) sorbent recovery and 96.3% (± 9%) Hg removal. The mass balance has been closed to within approximately ± 15%. PMID:22104766

  16. MAGNET

    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...

  17. Optimization of magnetic powdered activated carbon for aqueous Hg(II) removal and magnetic recovery

    Faulconer, Emily K., E-mail: emily.faulconer@yahoo.com [Department of Environmental Engineering Sciences, University of Florida, 217 Black Hall, P.O. Box 116450, Gainesville, FL 32611-645 (United States); Hoogesteijn von Reitzenstein, Natalia V.; Mazyck, David W. [Department of Environmental Engineering Sciences, University of Florida, 217 Black Hall, P.O. Box 116450, Gainesville, FL 32611-645 (United States)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Thermal oxidation of MPAC decreased the amorphous characteristic of iron oxides. Black-Right-Pointing-Pointer Thermal oxidation did not influence magnetic recovery or Hg removal performance. Black-Right-Pointing-Pointer At all thermal oxidation temperatures, the 3:1 MPAC achieved the highest Hg removal. - Abstract: Activated carbon is known to adsorb aqueous Hg(II). MPAC (magnetic powdered activated carbon) has the potential to remove aqueous Hg to less than 0.2 {mu}g/L while being magnetically recoverable. Magnetic recapture allows simple sorbent separation from the waste stream while an isolated waste potentially allows for mercury recycling. MPAC Hg-removal performance is verified by mercury mass balance, calculated by quantifying adsorbed, volatilized, and residual aqueous mercury. The batch reactor contained a sealed mercury-carbon contact chamber with mixing and constant N{sub 2} (g) headspace flow to an oxidizing trap. Mercury adsorption was performed using spiked ultrapure water (100 {mu}g/L Hg). Mercury concentrations were obtained using EPA method 245.1 and cold vapor atomic absorption spectroscopy. MPAC synthesis was optimized for Hg removal and sorbent recovery according to the variables: C:Fe, thermal oxidation temperature and time. The 3:1 C:Fe preserved most of the original sorbent surface area. As indicated by XRD patterns, thermal oxidation reduced the amorphous characteristic of the iron oxides but did not improve sorbent recovery and damaged porosity at higher oxidation temperatures. Therefore, the optimal synthesis variables, 3:1 C:Fe mass ratio without thermal oxidation, which can achieve 92.5% ({+-}8.3%) sorbent recovery and 96.3% ({+-}9%) Hg removal. The mass balance has been closed to within approximately {+-}15%.

  18. Magnetic refrigerator for hydrogen liquefaction

    Matsumoto, K; Kondo, T [Department of Physics, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 (Japan); Yoshioka, S; Kamiya, K; Numazawa, T [Tsukuba Magnet Laboratory, National Institute for Materials Science, 3-13 Sakura, Tsukuba 305-0003 (Japan)], E-mail: kmatsu@kenroku.kanazawa-u.ac.jp

    2009-02-01

    Magnetic refrigeration which is based on the magnetocaloric effect of solids has the potential to achieve high thermal efficiency for hydrogen liquefaction. We have been developing a magnetic refrigerator for hydrogen liquefaction which cools down hydrogen gas from liquid natural gas temperature and liquefies at 20 K. The magnetic liquefaction system consists of two magnetic refrigerators: Carnot magnetic refrigerator (CMR) and active magnetic regenerator (AMR) device. CMR with Carnot cycle succeeded in liquefying hydrogen at 20K. Above liquefaction temperature, a regenerative refrigeration cycle should be necessary to precool hydrogen gas, because adiabatic temperature change of magnetic material is reduced due to a large lattice specific heat of magnetic materials. We have tested an AMR device as the precooling stage. It was confirmed for the first time that AMR cycle worked around 20 K.

  19. Magnetic refrigerator for hydrogen liquefaction

    Magnetic refrigeration which is based on the magnetocaloric effect of solids has the potential to achieve high thermal efficiency for hydrogen liquefaction. We have been developing a magnetic refrigerator for hydrogen liquefaction which cools down hydrogen gas from liquid natural gas temperature and liquefies at 20 K. The magnetic liquefaction system consists of two magnetic refrigerators: Carnot magnetic refrigerator (CMR) and active magnetic regenerator (AMR) device. CMR with Carnot cycle succeeded in liquefying hydrogen at 20K. Above liquefaction temperature, a regenerative refrigeration cycle should be necessary to precool hydrogen gas, because adiabatic temperature change of magnetic material is reduced due to a large lattice specific heat of magnetic materials. We have tested an AMR device as the precooling stage. It was confirmed for the first time that AMR cycle worked around 20 K.

  20. Regeneration of neural crest derivatives in the Xenopus tadpole tail

    Slack Jonathan MW

    2007-05-01

    Full Text Available Abstract Background After amputation of the Xenopus tadpole tail, a functionally competent new tail is regenerated. It contains spinal cord, notochord and muscle, each of which has previously been shown to derive from the corresponding tissue in the stump. The regeneration of the neural crest derivatives has not previously been examined and is described in this paper. Results Labelling of the spinal cord by electroporation, or by orthotopic grafting of transgenic tissue expressing GFP, shows that no cells emigrate from the spinal cord in the course of regeneration. There is very limited regeneration of the spinal ganglia, but new neurons as well as fibre tracts do appear in the regenerated spinal cord and the regenerated tail also contains abundant peripheral innervation. The regenerated tail contains a normal density of melanophores. Cell labelling experiments show that melanophores do not arise from the spinal cord during regeneration, nor from the mesenchymal tissues of the skin, but they do arise by activation and proliferation of pre-existing melanophore precursors. If tails are prepared lacking melanophores, then the regenerates also lack them. Conclusion On regeneration there is no induction of a new neural crest similar to that seen in embryonic development. However there is some regeneration of neural crest derivatives. Abundant melanophores are regenerated from unpigmented precursors, and, although spinal ganglia are not regenerated, sufficient sensory systems are produced to enable essential functions to continue.

  1. Control of active liquid crystals with a magnetic field.

    Guillamat, Pau; Ignés-Mullol, Jordi; Sagués, Francesc

    2016-05-17

    Living cells sense the mechanical features of their environment and adapt to it by actively remodeling their peripheral network of filamentary proteins, known as cortical cytoskeleton. By mimicking this principle, we demonstrate an effective control strategy for a microtubule-based active nematic in contact with a hydrophobic thermotropic liquid crystal. By using well-established protocols for the orientation of liquid crystals with a uniform magnetic field, and through the mediation of anisotropic shear stresses, the active nematic reversibly self-assembles with aligned flows and textures that feature orientational order at the millimeter scale. The turbulent flow, characteristic of active nematics, is in this way regularized into a laminar flow with periodic velocity oscillations. Once patterned, the microtubule assembly reveals its intrinsic length and time scales, which we correlate with the activity of motor proteins, as predicted by existing theories of active nematics. The demonstrated commanding strategy should be compatible with other viable active biomaterials at interfaces, and we envision its use to probe the mechanics of the intracellular matrix. PMID:27140604

  2. Evolution of the Magnetic Field Distribution of Active Regions

    Dacie, Sally; van Driel-Gesztelyi, Lidia; Long, David; Baker, Deb; Janvier, Miho; Yardley, Stephanie; Pérez-Suárez, David

    2016-01-01

    Aims. Although the temporal evolution of active regions (ARs) is relatively well understood, the processes involved continue to be the subject of investigation. We study how the magnetic field of a series of ARs evolves with time to better characterise how ARs emerge and disperse. Methods. We examine the temporal variation in the magnetic field distribution of 37 emerging ARs. A kernel density estimation plot of the field distribution was created on a log-log scale for each AR at each time step. We found that the central portion of the distribution is typically linear and its slope was used to characterise the evolution of the magnetic field. Results. The slopes were seen to evolve with time, becoming less steep as the fragmented emerging flux coalesces. The slopes reached a maximum value of ~ -1.5 just before the time of maximum flux before becoming steeper during the decay phase towards the quiet Sun value of ~ -3. This behaviour differs significantly from a classical diffusion model, which produces a slope...

  3. Photocatalytically active titanium dioxide nanopowders: Synthesis, photoactivity and magnetic separation

    Two approaches were used to obtain nanocrystalline titanium dioxide (TiO2) photocatalyst powders. Firstly, low-temperature synthesis method and secondly liquid flame spraying. The structural properties of the produced powders were determined with X-ray diffraction, transmission electron microscopy and nitrogen adsorption tests. The photocatalytic properties of the powders were studied with methylene blue (MB) discoloration tests. After discolorations tests, TiO2 was coagulated with magnetite particles using FeCl3·6 H2O at a fixed pH value. Magnetic separation of coagulated TiO2 and magnetite was carried out by a permanent magnet. The obtained results showed that the particle size of the powders synthesized at low-temperature was very small and the specific surface area high. The phase content of the powder was also shown to depend greatly on the acidity of the synthesis solution. Powder synthesized by liquid flame spraying was mixture of anatase and rutile phases with essentially larger particle size and lower specific surface area than those of low-temperature synthesized powders. The MB discoloration test showed that photocatalytic activity depends on the phase structure as well as the specific surface area of the synthesized TiO2 powder. The magnetic separation of TiO2–magnetite coagulate from solution proved to be efficient around pH:8

  4. Solar activity, magnetic storms and their effects on biological systems

    Full text: In the present time much attention is spent on the electromagnetic waves, solar radiation and magnetic storms on biological systems, including on person. However, there are few publications describing the mechanism of these influences on human. First of all it is necessary to point out that electromagnetic waves, the flow of particles in space and magnetic storms, acting on person human-all is connected with biophysical processes. So approach to influence of these factors on organism follows the processes of influence of these waves on bio system. Magnetic storms are phenomena continuously connected with solar activity. Investigation of cosmic space has intensified the practical importance of the problem of interaction with natural factors of external ambience. Much attention deserves the cosmic radiation, geomagnetic field, elements of climate and weathers. However the mechanism of bio tropic action of these factors is not enough studied. Beginning XXI century was already signified the successes in investigation of Mars. The Space shuttles 'Spirit' and 'Opportunity' successfully have carried out some work on examining and finding of water on Mars. A flight of person to Mars is being considered. One of the important mechanisms of influence on human organism is, in our opinion, the rising of the resonance at coincidence of frequencies and their more important factor is a phenomena of electromagnetic induction and forming the radicals in the organism

  5. Three-axis active magnetic attitude control asymptotical study

    Ovchinnikov, M. Yu.; Roldugin, D. S.; Penkov, V. I.

    2015-05-01

    Active magnetic attitude control system providing given inertial attitude is considered. Control algorithm is constructed on the basis of a planar motion model. It decreases attitude discrepancy. Alternative approach is based on the PD-controller design. System behavior is analyzed for specific motion cases and sometimes for specific inertia tensor (axisymmetrical satellite) using averaging technique. Overall satellite angular motion is covered. Necessary attitude is found to be accessible for some control parameters. Stability is proven and optimal algorithm parameters are obtained. Floquet-based analysis is performed to verify and broaden analytical results.

  6. Failure Mode and Effect Analysis of Active Magnetic Bearings

    K.P. Lijesh

    2016-03-01

    Full Text Available In the present research work Failure Mode and Effect Analysis (FMEA of an Active Magnetic Bearing (AMB has been presented. Various possible failures modes of AMBs and the corresponding effects of those failures on performance of AMBs have been identified. The identified failure modes of AMBs will facilitate designer to incorporate necessary design features that would prevent the occurrence of the failure. The severity, occurrence and detection of the failures modes are determined based on a rating scale of 1 to 5 to quantify the Risk Priority Number (RPN of the failure modes. The methods to eliminate or reduce the high-risk-failure modes are proposed.

  7. Photometric magnetic-activity metrics tested with the Sun: Application to Kepler M dwarfs

    Mathur, S; Garcia, R A; Ceillier, T

    2014-01-01

    The Kepler mission has been providing high-quality photometric data leading to many breakthroughs in the exoplanet search and in stellar physics. Stellar magnetic activity results from the interaction between rotation, convection, and magnetic field. Constraining these processes is important if we want to better understand stellar magnetic activity. Using the Sun, we want to test a magnetic activity index based on the analysis of the photo- metric response and then apply it to a sample of M dwarfs observed by Kepler. We estimate a global stellar magnetic activity index by measuring the standard deviation of the whole time series, Sph. Because stellar variability can be related to convection, pulsations, or magnetism, we need to ensure that this index mostly takes into account magnetic effects. We define another stellar magnetic activity index as the average of the standard deviation of shorter subseries which lengths are determined by the rotation period of the star. This way we can ensure that the measured p...

  8. Contribution to magnetic refrigeration study at liquid helium study

    An experimental prototype of magnetic refrigerator operates, following a Carnot cycle, with gallium gadolinium garnet, from liquid helium at 4.20K. Analysis of the cyle and heat exchanges allowed to improve performance up to get more than 50% of Carnot yield at 1.80K and nearly 80% at 2.10K. Operation conditions of a regenerator refrigerator between 4 and 200K are studied. The association of a magnetic refrigerator and a gas refrigerator is analyzed. Among different ways to realize the magnetic stage, an active regenerator cycle is chosen. An experimental device is described

  9. The Helioseismic and Magnetic Imager (HMI) Vector Magnetic Field Pipeline: SHARPs -- Space-weather HMI Active Region Patches

    Bobra, Monica G; Hoeksema, J Todd; Turmon, Michael J; Liu, Yang; Hayashi, Keiji; Barnes, Graham; Leka, K D

    2014-01-01

    A new data product from the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) called Space-weather HMI Active Region Patches (SHARPs) is now available. SDO/HMI is the first space-based instrument to map the full-disk photospheric vector magnetic field with high cadence and continuity. The SHARP data series provide maps in patches that encompass automatically tracked magnetic concentrations for their entire lifetime; map quantities include the photospheric vector magnetic field and its uncertainty, along with Doppler velocity, continuum intensity, and line-of-sight magnetic field. Furthermore, keywords in the SHARP data series provide several parameters that concisely characterize the magnetic-field distribution and its deviation from a potential-field configuration. These indices may be useful for active-region event forecasting and for identifying regions of interest. The indices are calculated per patch and are available on a twelve-minute cadence. Quick-look data are avail...

  10. Regeneration performance of CO2-rich solvents by using membrane vacuum regeneration technology: Relationships between absorbent structure and regeneration efficiency

    Highlights: ► MVR may be viable to successfully use less valuable heat to replace high grade steam. ► Increasing OH and amine groups will increase the regeneration efficiency. ► Absorbents with a four carbon chain length will be more attractive to MVR. ► Amino acid salts will be more appropriate for MVR. ► HRM conducted at ambient pressure and low temperature is inferior to MVR. -- Abstract: In order to give a better understanding for the selection of suitable absorbents for the novel membrane vacuum regeneration technology (MVR) which has the potential to reduce CO2 energy requirement by utilizing the waste heat or low-grade energy, an experimental study to determine the relationships between chemical structure and vacuum regeneration behavior of CO2 absorbents at 70 °C and 10 kPa was performed. Eleven typical absorbents with different functional groups in their chemical structures were investigated in terms of vacuum regeneration efficiencies. Results showed that the regeneration efficiency decreased with an increase of number of activated hydrogen atom in amine group and decreased with the number of hydroxyl group. Especially, more attention should be paid to these alkanolamines with one hydrogen atom in amine group and two or more hydroxyl groups in the structures due to their better comprehensive performance in regeneration, absorbent loss and CO2 absorption aspects. Increasing the carbon chain length and amine groups in the absorbent structure contributed to the improvement of regeneration performance and reduction of absorbent volatile loss. These absorbents with a four carbon chain length bonded at amine group might be more attractive to MVR. Furthermore, polyamines were superior to monoamines in terms of higher regeneration efficiencies and lower absorbent losses. Additionally, the individual effects of the potassium carboxylate group and hydroxymethylene group were also compared in this study. Results showed that amino acid salts were more

  11. The Magnetic Classification of Solar Active Regions 1992-2015

    Jaeggli, S. A.; Norton, A. A.

    2016-03-01

    The purpose of this Letter is to address a blindspot in our knowledge of solar active region (AR) statistics. To the best of our knowledge, there are no published results showing the variation of the Mount Wilson magnetic classifications as a function of solar cycle based on modern observations. We show statistics for all ARs reported in the daily Solar Region Summary from 1992 January 1 to 2015 December 31. We find that the α and β class ARs (including all sub-groups, e.g., βγ, βδ) make up fractions of approximately 20% and 80% of the sample, respectively. This fraction is relatively constant during high levels of activity however, an increase in the α fraction to about 35% and and a decrease in the β fraction to about 65% can be seen near each solar minimum and are statistically significant at the 2σ level. Over 30% of all ARs observed during the years of solar maxima were appended with the classifications γ and/or δ, while these classifications account for only a fraction of a percent during the years near the solar minima. This variation in the AR types indicates that the formation of complex ARs may be due to the pileup of frequent emergence of magnetic flux during solar maximum, rather than the emergence of complex, monolithic flux structures.

  12. Observational evidence for enhanced magnetic activity of superflare stars.

    Karoff, Christoffer; Knudsen, Mads Faurschou; De Cat, Peter; Bonanno, Alfio; Fogtmann-Schulz, Alexandra; Fu, Jianning; Frasca, Antonio; Inceoglu, Fadil; Olsen, Jesper; Zhang, Yong; Hou, Yonghui; Wang, Yuefei; Shi, Jianrong; Zhang, Wei

    2016-01-01

    Superflares are large explosive events on stellar surfaces one to six orders-of-magnitude larger than the largest flares observed on the Sun throughout the space age. Due to the huge amount of energy released in these superflares, it has been speculated if the underlying mechanism is the same as for solar flares, which are caused by magnetic reconnection in the solar corona. Here, we analyse observations made with the LAMOST telescope of 5,648 solar-like stars, including 48 superflare stars. These observations show that superflare stars are generally characterized by larger chromospheric emissions than other stars, including the Sun. However, superflare stars with activity levels lower than, or comparable to, the Sun do exist, suggesting that solar flares and superflares most likely share the same origin. The very large ensemble of solar-like stars included in this study enables detailed and robust estimates of the relation between chromospheric activity and the occurrence of superflares. PMID:27009381

  13. The Magnetic Classification of Solar Active Regions 1992 - 2015

    Jaeggli, Sarah A

    2016-01-01

    The purpose of this letter is to address a blind-spot in our knowledge of solar active region statistics. To the best of our knowledge there are no published results showing the variation of the Mount Wilson magnetic classifications as a function of solar cycle based on modern observations. We show statistics for all active regions reported in the daily Solar Region Summary from 1992 January 1 to 2015 December 31. We find that the $\\alpha$ and $\\beta$ class active regions (including all sub-groups e.g. $\\beta\\gamma$, $\\beta\\delta$) make up fractions of approximately 20% and 80% of the sample respectively. This fraction is relatively constant during high levels of activity, however, an increase in the $\\alpha$ fraction to about 35% and and a decrease in the $\\beta$ fraction to about 65% can be seen near each solar minimum and is statistically significant at the 2-$\\sigma$ level. Over 30% of all active regions observed during the years of solar maxima were appended with the classifications $\\gamma$ and/or $\\del...

  14. Magnetic Activity Cycles in the Exoplanet Host Star epsilon Eridani

    Metcalfe, T S; Brown, B P; Mathur, S; Soderblom, D R; Henry, T J; Mauas, P J D; Petrucci, R; Hall, J C; Basu, S

    2012-01-01

    The active K2 dwarf epsilon Eri has been extensively characterized, both as a young solar analog and more recently as an exoplanet host star. As one of the nearest and brightest stars in the sky, it provides an unparalleled opportunity to constrain stellar dynamo theory beyond the Sun. We confirm and document the 3 year magnetic activity cycle in epsilon Eri originally reported by Hatzes and coworkers, and we examine the archival data from previous observations spanning 45 years. The data show coexisting 3 year and 13 year periods leading into a broad activity minimum that resembles a Maunder minimum-like state, followed by the resurgence of a coherent 3 year cycle. The nearly continuous activity record suggests the simultaneous operation of two stellar dynamos with cycle periods of 2.95+/-0.03 years and 12.7+/-0.3 years, which by analogy with the solar case suggests a revised identification of the dynamo mechanisms that are responsible for the so-called "active" and "inactive" sequences as proposed by Bohm-V...

  15. Desulfurization sorbent regeneration

    Jalan, V.M.; Frost, D.G.

    1982-07-07

    A spent solid sorbent resulting from the removal of hydrogen sulfide from a fuel gas flow is regenerated with a steam-air mixture. The mixture of steam and air may also include additional nitrogen or carbon dioxide. The gas mixture contacts the spent sorbent containing metal sulfide at a temperature above 500/sup 0/C to regenerate the sulfide to metal oxide or carbonate. Various metal species including the period four transition metals and the lanthanides are suitable sorbents that may be regenerated by this method. In addition, the introduction of carbon dioxide gas permits carbonates such as those of strontium, barium and calcium to be regenerated. The steam permits regeneration of spent sorbent without formation of metal sulfate. Moreover, the regeneration will proceed with low oxygen concentrations and will occur without the increase in temperature to minimize the risk of sintering and densification of the sorbent. This method may be used for high-temperature fuel cells.

  16. Stirling convertor regenerators

    Ibrahim, Mounir B

    2011-01-01

    Stirling Convertor Regenerators addresses the latest developments and future possibilities in the science and practical application of Stirling engine regenerators and technology. Written by experts in the vanguard of alternative energy, this invaluable resource presents integral scientific details and design concepts associated with Stirling converter regenerators. Content is reinforced with novel insights and remarkable firsthand experience that the authors and their colleagues acquired while working at the National Aeronautics and Space Administration (NASA) and other leading organizations.

  17. Modulation of tissue repair by regeneration enhancer elements.

    Kang, Junsu; Hu, Jianxin; Karra, Ravi; Dickson, Amy L; Tornini, Valerie A; Nachtrab, Gregory; Gemberling, Matthew; Goldman, Joseph A; Black, Brian L; Poss, Kenneth D

    2016-04-14

    How tissue regeneration programs are triggered by injury has received limited research attention. Here we investigate the existence of enhancer regulatory elements that are activated in regenerating tissue. Transcriptomic analyses reveal that leptin b (lepb) is highly induced in regenerating hearts and fins of zebrafish. Epigenetic profiling identified a short DNA sequence element upstream and distal to lepb that acquires open chromatin marks during regeneration and enables injury-dependent expression from minimal promoters. This element could activate expression in injured neonatal mouse tissues and was divisible into tissue-specific modules sufficient for expression in regenerating zebrafish fins or hearts. Simple enhancer-effector transgenes employing lepb-linked sequences upstream of pro- or anti-regenerative factors controlled the efficacy of regeneration in zebrafish. Our findings provide evidence for 'tissue regeneration enhancer elements' (TREEs) that trigger gene expression in injury sites and can be engineered to modulate the regenerative potential of vertebrate organs. PMID:27049946

  18. ON MAGNETIC ACTIVITY BAND OVERLAP, INTERACTION, AND THE FORMATION OF COMPLEX SOLAR ACTIVE REGIONS

    McIntosh, Scott W. [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307 (United States); Leamon, Robert J., E-mail: mscott@hao.ucar.edu [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

    2014-11-20

    Recent work has revealed a phenomenological picture of the how the ∼11 yr sunspot cycle of the Sun arises. The production and destruction of sunspots is a consequence of the latitudinal-temporal overlap and interaction of the toroidal magnetic flux systems that belong to the 22 yr magnetic activity cycle and are rooted deep in the Sun's convective interior. We present a conceptually simple extension of this work, presenting a hypothesis on how complex active regions can form as a direct consequence of the intra- and extra-hemispheric interaction taking place in the solar interior. Furthermore, during specific portions of the sunspot cycle, we anticipate that those complex active regions may be particularly susceptible to profoundly catastrophic breakdown, producing flares and coronal mass ejections of the most severe magnitude.

  19. Inertia Wheel on Low-Noise Active Magnetic Suspension

    Carabelli, S.; Genta, G.; Silvagni, M.; Tonoli, A.

    2002-01-01

    Magnetic bearings are particularly suited for space applications for a number of reasons: - they are ideally suited for vacuum applications; - the lack of lubrication and wear enhances the reliability and guaranties a long maintenance-free operation - the low drag torque decreases power consumption and reduces the torque exerted on the stator of the machine. - the possibility of insulating actively the spacecraft from the excitation due to unbalance of the rotating system In the case of reaction wheels, a well designed magnetic suspension allows high speed operation with a very low power consumption and vibration level. Conversely, microgravity (and possibly vacuum) operation is an advantage for magnetic bearings. The absence of static forces allows to operate with low current levels, thus reducing electrical noise and allowing to reach even lower vibration levels than in Earth applications of magnetic bearings. Active magnetic bearings (AMB) allow to adapt the working characteristics of the system to the operating needs: it is possible to use the actuators to lock the system during launch (absence of grabbers) and to stiffen the suspension when the spacecraft is accelerated (impulsive phases), while working in conditions optimised for microgravity when this is needed. Magnetic suspension systems designed for microgravity environment cannot be correctly tested on the ground. Testing in ground conditions results in the need of grossly overdesigning the levitation device; furthermore, in some cases ground testing is completely impossible, if not by introducing devices which compensate for the Earth gravitational field. If the compensation for the gravitational force is supplied by the same actuators used for microgravity operation, the actuators and the power amplifiers must be overdesigned and in some cases the suspension can be altogether impossible. They work in conditions which are much different from nominal ones and, above all, it is impossible to reach the

  20. Roles of superconducting magnetic bearings and active magnetic bearings in attitude control and energy storage flywheel

    Compared with conventional energy storage flywheel, the rotor of attitude control and energy storage flywheel (ACESF) used in space not only has high speed, but also is required to have precise and stable direction. For the presented superconducting magnetic bearing (SMB) and active magnetic bearing (AMB) suspended ACESF, the rotor model including gyroscopic couples is established originally by taking the properties of SMB and AMB into account, the forces of SMB and AMB are simplified by linearization within their own neighbors of equilibrium points. For the high-speed rigid discal rotor with large inertia, the negative effect of gyroscopic effect of rotor is prominent, the radial translation and tilting movement of rotor suspended by only SMB, SMB with equivalent PMB, or SMB together with PD controlled AMB are researched individually. These analysis results proved originally that SMB together with AMB can make the rotor be stable and make the radial amplitude of the vibration of rotor be small while the translation of rotor suspended by only SMB or SMB and PM is not stable and the amplitude of this vibration is large. For the stability of the high-speed rotor in superconducting ACESF, the AMB can suppress the nutation and precession of rotor effectively by cross-feedback control based on the separated PD type control or by other modern control methods.

  1. Expressing Constitutively Active Rheb in Adult Dorsal Root Ganglion Neurons Enhances the Integration of Sensory Axons that Regenerate Across a Chondroitinase-Treated Dorsal Root Entry Zone Following Dorsal Root Crush.

    Wu, Di; Klaw, Michelle C; Kholodilov, Nikolai; Burke, Robert E; Detloff, Megan R; Côté, Marie-Pascale; Tom, Veronica J

    2016-01-01

    While the peripheral branch of dorsal root ganglion neurons (DRG) can successfully regenerate after injury, lesioned central branch axons fail to regrow across the dorsal root entry zone (DREZ), the interface between the dorsal root and the spinal cord. This lack of regeneration is due to the limited regenerative capacity of adult sensory axons and the growth-inhibitory environment at the DREZ, which is similar to that found in the glial scar after a central nervous system (CNS) injury. We hypothesized that transduction of adult DRG neurons using adeno-associated virus (AAV) to express a constitutively-active form of the GTPase Rheb (caRheb) will increase their intrinsic growth potential after a dorsal root crush. Additionally, we posited that if we combined that approach with digestion of upregulated chondroitin sulfate proteoglycans (CSPG) at the DREZ with chondroitinase ABC (ChABC), we would promote regeneration of sensory axons across the DREZ into the spinal cord. We first assessed if this strategy promotes neuritic growth in an in vitro model of the glial scar containing CSPG. ChABC allowed for some regeneration across the once potently inhibitory substrate. Combining ChABC treatment with expression of caRheb in DRG significantly improved this growth. We then determined if this combination strategy also enhanced regeneration through the DREZ after dorsal root crush in adult rats in vivo. After unilaterally crushing C4-T1 dorsal roots, we injected AAV5-caRheb or AAV5-GFP into the ipsilateral C5-C8 DRGs. ChABC or PBS was injected into the ipsilateral dorsal horn at C5-C8 to digest CSPG, for a total of four animal groups (caRheb + ChABC, caRheb + PBS, GFP + ChABC, GFP + PBS). Regeneration was rarely observed in PBS-treated animals, whereas short-distance regrowth across the DREZ was observed in ChABC-treated animals. No difference in axon number or length between the ChABC groups was observed, which may be related to intraganglionic inflammation induced by the

  2. Fgf regulates dedifferentiation during skeletal muscle regeneration in adult zebrafish.

    Saera-Vila, Alfonso; Kish, Phillip E; Kahana, Alon

    2016-09-01

    Fibroblast growth factors (Fgfs) regulate critical biological processes such as embryonic development, tissue homeostasis, wound healing, and tissue regeneration. In zebrafish, Fgf signaling plays an important role in the regeneration of the spinal cord, liver, heart, fin, and photoreceptors, although its exact mechanism of action is not fully understood. Utilizing an adult zebrafish extraocular muscle (EOM) regeneration model, we demonstrate that blocking Fgf receptor function using either a chemical inhibitor (SU5402) or a dominant-negative transgenic construct (dnFGFR1a:EGFP) impairs muscle regeneration. Adult zebrafish EOMs regenerate through a myocyte dedifferentiation process, which involves a muscle-to-mesenchyme transition and cell cycle reentry by differentiated myocytes. Blocking Fgf signaling reduced cell proliferation and active caspase 3 levels in the regenerating muscle with no detectable levels of apoptosis, supporting the hypothesis that Fgf signaling is involved in the early steps of dedifferentiation. Fgf signaling in regenerating myocytes involves the MAPK/ERK pathway: inhibition of MEK activity with U0126 mimicked the phenotype of the Fgf receptor inhibition on both muscle regeneration and cell proliferation, and activated ERK (p-ERK) was detected in injured muscles by immunofluorescence and western blot. Interestingly, following injury, ERK2 expression is specifically induced and activated by phosphorylation, suggesting a key role in muscle regeneration. We conclude that the critical early steps of myocyte dedifferentiation in EOM regeneration are dependent on Fgf signaling. PMID:27267062

  3. Deciphering solar magnetic activity. I. On the relationship between the sunspot cycle and the evolution of small magnetic features

    Sunspots are a canonical marker of the Sun's internal magnetic field which flips polarity every ∼22 yr. The principal variation of sunspots, an ∼11 yr variation, modulates the amount of the magnetic field that pierces the solar surface and drives significant variations in our star's radiative, particulate, and eruptive output over that period. This paper presents observations from the Solar and Heliospheric Observatory and Solar Dynamics Observatory indicating that the 11 yr sunspot variation is intrinsically tied to the spatio-temporal overlap of the activity bands belonging to the 22 yr magnetic activity cycle. Using a systematic analysis of ubiquitous coronal brightpoints and the magnetic scale on which they appear to form, we show that the landmarks of sunspot cycle 23 can be explained by considering the evolution and interaction of the overlapping activity bands of the longer-scale variability.

  4. Effect of Magnetic Field on Enzyme Activities in Main Soils of Northeast China

    LIUXIAOYI; YIYANLI; 等

    1996-01-01

    Soil enzyme activities as affected by applied magnetic field were studied with three main soils (brown soil,black soil and albic soil) collected from Northeast China,Appropriate intensities of magnetic field could obviously enhance the activities of hydrogen peroxidases,invertases,amylases and phosphatases in the three soils,although the effect varied with types and water regimes of the soils.Increasing times of magnetic treatment could multiple its good effect on the activities of hydrogen peroxidases in soils.

  5. Thermal activation-induced sweep-rate dependence of magnetic switching astroid

    We examine the sweep-rate dependence of magnetic switching field, Hs, in submicron magnetic tunnel junctions where shape anisotropy is dominant. Experimental data support the use of a single-domain thermal activation model for description of activated magnetic reversal in junctions 0.2 by 0.5 μm or less in size. A scaling law is obtained for the thermal activation energy which varies as the cube of junction size. [copyright] 2001 American Institute of Physics

  6. Financing Property's Contribution to Regeneration

    Alastair Adair; Jim Berry; Stanley McGreal

    2003-01-01

    Attracting investment and finance into inner-city and other renewal areas poses particular difficulties and is frequently reliant on strong public-sector commitment through special incentives or other mechanisms to provide the conditions to lever private-sector activity. This paper initially links the concept of market failure and the rationale for regeneration and examines policy responses from UK, European and US perspectives, followed by a consideration of public- and private-sector financ...

  7. Asymmetric magnetic disorder observed in thermally activated magnetization reversal of exchange-biased IrMn/CoFe films

    We report an asymmetry of magnetic disorder in exchange-biased IrMn(tIrMn=5–20 nm)/CoFe(50 nm) films observed by means of a Kerr microscope, capable of direct domain observation. From the correlation between the magnetization half-reversal time and applied magnetic field, we find that the magnetization switching in all the films occurs via a thermally activated reversal mechanism for both branches of hysteresis loops. Surprisingly, in the forward branch reversal where the applied magnetic field is antiparallel to the direction of exchange-bias field, degree of magnetic disorder decreases as exchange-bias field increases, which is definitely contrasted with the case of backward branch reversal. This result is likely ascribed to the fact that the local values of exchange-bias field and coercive field are oppositely fluctuating with each other in the film. - Highlights: ► Quite different “magnetic disorder” in the same structural-disordered system. ► Elucidation of magnetization reversal mechanism via direct domain observation. ► The simple model which explains the origin of asymmetric magnetic disorder.

  8. Heterogeneous adsorption and catalytic oxidation of benzene, toluene and xylene over spent and chemically regenerated platinum catalyst supported on activated carbon

    Shim, Wang Geun; Kim, Sang Chai

    2010-06-01

    The heterogeneous adsorption and catalytic oxidation of benzene, toluene and o-xylene (BTX) over the spent platinum catalyst supported on activated carbon (Pt/AC) as well as the chemically treated spent catalysts were studied to understand their catalytic and adsorption activities. Sulfuric aqueous acid solution (0.1N, H 2SO 4) was used to regenerate the spent Pt/AC catalyst. The physico-chemical properties of the catalysts in the spent and chemically treated states were analyzed by using nitrogen adsorption-desorption isotherm and elemental analysis (EDX). The gravimetric adsorption and the light-off curve analysis were employed to study the BTX adsorption and oxidation on the spent catalyst and its modified Pt/AC catalysts. The experimental results indicate that the spent Pt/AC catalyst treated with the H 2SO 4 aqueous solution has a higher toluene adsorption and conversion ability than that of the spent Pt/AC catalyst. A further studies of H 2SO 4 treated Pt/AC catalyst on their catalytic and heterogeneous adsorption behaviours for BTX revealed that the activity of the H 2SO 4 treated Pt/AC catalyst follows the sequence of benzene > toluene > o-xylene. The adsorption equilibrium isotherms of BTX on the H 2SO 4 treated Pt/AC were measured at different temperatures ranging from 120 to 180 °C. To correlate the equilibrium data and evaluate their adsorption affinity for BTX, the two sites localized Langmuir (L2m) isotherm model was employed. The heterogeneous surface feature of the H 2SO 4 treated Pt/AC was described in detail with the information obtained from the results of isosteric enthalpy of adsorption and adsorption energy distributions. Furthermore, the activity of H 2SO 4 treated Pt/AC about BTX was found to be directly related to the Henry's constant, isosteric enthalpy of adsorption and adsorption energy distribution functions.

  9. Formation of Solar Delta Active Regions:Twist and Writhe of Magnetic Ropes

    Hong-Qi Zhang

    2004-01-01

    We analyze the process of formation of delta configuration in some well-known super active regions based on photospheric vector magnetogram observations. It is found that the magnetic field in the initial developing stage of some delta active regions shows a potential-like configuration in the solar atmosphere,the magnetic shear develops mainly near the magnetic neutral line with magnetic islands of opposite polarities, and the large-scale photospheric twisted field forming gradually later. Some results are obtained: (1) The analysis of magnetic writhe of whole active regions cannot be limited in the strong field of sunspots, because the contribution of the fraction of decayed magnetic field is non-negligible. (2) The magnetic model of kink magnetic ropes, supposed to be generated in the subatmosphere,is not consistent with the evolution of large-scale twisted photospheric transverse magnetic field and not entirely consistent with the relationship with magnetic shear in some delta active regions. (3) The proposition is that the large-scale delta active regions are formed from contribution by small-scale non-potential magnetic flux bundles generated in the subatmosphere.

  10. Activity Analyses for Solar-Type Stars Observed With Kepler. I. Proxies of Magnetic Activity

    He, Han; Yun, Duo

    2016-01-01

    Light curves of solar-type stars often show gradual fluctuations due to rotational modulation by magnetic features (starspots and faculae) on stellar surfaces. Two quantitative measures of modulated light curves are employed as the proxies of magnetic activity for solar-type stars observed with Kepler telescope. The first is named autocorrelation index $i_{AC}$, which describes the degree of periodicity of the light curve, the second is the effective fluctuation range of the light curve $R_{eff}$, which reflects the depth of rotational modulation. The two measures are complementary and depict different aspects of magnetic activities on solar-type stars. By using the two proxies $i_{AC}$ and $R_{eff}$, we analyzed activity properties of two carefully selected solar-type stars observed with Kepler (Kepler ID: 9766237 and 10864581), which have distinct rotational periods (14.7 vs. 6.0 days). We also applied the two measures to the Sun for a comparative study. The result shows that both the measures can reveal cy...

  11. Bone marrow stromal/stem cell-derived extracellular vesicles regulate osteoblast activity and differentiation in vitro and promote bone regeneration in vivo

    Yunhao Qin; Lian Wang; Zhengliang Gao; Genyin Chen; Changqing Zhang

    2016-01-01

    Emerging evidence suggests that extracellular vesicles (EVs) are secreted by diverse tissues and play important roles in cell-cell communication, organ interactions and tissue homeostasis. Studies have reported the use of EVs to stimulate tissue regeneration, such as hepatic cell regeneration, and to treat diseases, such as pulmonary hypertension. However, little is known about the osteogenic effect of EVs. In this study, we explore the role of bone marrow stromal cell-derived EVs in the regu...

  12. Pulp Regeneration: Current Approaches and Future Challenges

    Yang, Jingwen; Yuan, Guohua; Chen, Zhi

    2016-01-01

    Regenerative endodontics aims to replace inflamed/necrotic pulp tissues with regenerated pulp-like tissues to revitalize teeth and improve life quality. Pulp revascularization case reports, which showed successful clinical and radiographic outcomes, indicated the possible clinical application of pulp regeneration via cell homing strategy. From a clinical point of view, functional pulp-like tissues should be regenerated with the characterization of vascularization, re-innervation, and dentin deposition with a regulated rate similar to that of normal pulp. Efficient root canal disinfection and proper size of the apical foramen are the two requisite preconditions for pulp regeneration. Progress has been made on pulp regeneration via cell homing strategies. This review focused on the requisite preconditions and cell homing strategies for pulp regeneration. In addition to the traditionally used mechanical preparation and irrigation, antibiotics, irrigation assisted with EndoVac apical negative-pressure system, and ultrasonic and laser irradiation are now being used in root canal disinfection. In addition, pulp-like tissues could be formed with the apical foramen less than 1 mm, although more studies are needed to determine the appropriate size. Moreover, signaling molecules including stromal cell derived factor (SDF-1α), basic Fibroblast Growth Factor (bFGF), Platelet Derived Growth Factor (PDGF), stem cell factor (SCF), and Granulocyte Colony-Stimulating Factor (G-CSF) were used to achieve pulp-like tissue formation via a cell homing strategy. Studies on the cell sources of pulp regeneration might give some indications on the signaling molecular selection. The active recruitment of endogenous cells into root canals to regenerate pulp-like tissues is a novel concept that may offer an unprecedented opportunity for the near-term clinical translation of current biology-based therapies for dental pulp regeneration. PMID:27014076

  13. Evolution of Magnetic Helicity and Energy Spectra of Solar Active Regions

    Zhang, Hongqi; Sokoloff, D D

    2015-01-01

    We adopt an isotropic representation of the Fourier-transformed two-point correlation tensor of the magnetic field for estimating magnetic energy and helicity spectra as well as current helicity spectra of individual active regions and the change of their spectral indices with the solar cycle. The departure of the spectral index of current helicity from 5/3 is analyzed, and it is found that it is lower than that of magnetic energy. There is no obvious relationship between the change of the normalized magnetic helicity and the integral scale of the magnetic field for individual active regions. The evolution of the spectral index reflects the development and distribution of various scales of magnetic structures in active regions. It is found that around solar maximum the magnetic energy and helicity spectra are steeper.

  14. Electrospun magnetic nanofibre mats – A new bondable biomaterial using remotely activated magnetic heating

    Zhong, Yi [Department of Materials Engineering, University of British Columbia, Vancouver (Canada); Key Laboratory of Science & Technology of Eco-Textile, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai (China); Leung, Victor; Yuqin Wan, Lynn [Department of Materials Engineering, University of British Columbia, Vancouver (Canada); Dutz, Silvio [Institut für Biomedizinische Technik und Informatik, Technische Universität Ilmenau (Germany); Department of Nano Biophotonics, Leibniz Institute of Photonic Technology, Jena (Germany); Ko, Frank K., E-mail: frank.ko@ubc.ca [Department of Materials Engineering, University of British Columbia, Vancouver (Canada); Häfeli, Urs O., E-mail: urs.hafeli@ubc.ca [Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver (Canada)

    2015-04-15

    A solvothermal process was adopted to produce hydrophilic magnetite (Fe{sub 3}O{sub 4}) nanoparticles which were subsequently emulsified with a chloroform/methanol (70/30 v/v) solution of poly(caprolactone) (PCL) and then electrospun into a 0.2 mm thick PCL mat. The magnetic heating of the mats at a field amplitude of 25 kA/m and frequency of 400 kHz exhibited promising efficiency for magnetic hyperthermia, with a specific absorption rate of about 40 W/g for the magnetic mat. The produced heat was used to melt the magnetic mat onto the surrounding non-magnetic polymer mat from within, without destroying the nanostructure of the non-magnetic polymer more than 0.5 mm away. Magnetic nanofibre mats might thus be useful for internal heat sealing applications, and potentially also for thermotherapy.

  15. Electrospun magnetic nanofibre mats - A new bondable biomaterial using remotely activated magnetic heating

    Zhong, Yi; Leung, Victor; Yuqin Wan, Lynn; Dutz, Silvio; Ko, Frank K.; Häfeli, Urs O.

    2015-04-01

    A solvothermal process was adopted to produce hydrophilic magnetite (Fe3O4) nanoparticles which were subsequently emulsified with a chloroform/methanol (70/30 v/v) solution of poly(caprolactone) (PCL) and then electrospun into a 0.2 mm thick PCL mat. The magnetic heating of the mats at a field amplitude of 25 kA/m and frequency of 400 kHz exhibited promising efficiency for magnetic hyperthermia, with a specific absorption rate of about 40 W/g for the magnetic mat. The produced heat was used to melt the magnetic mat onto the surrounding non-magnetic polymer mat from within, without destroying the nanostructure of the non-magnetic polymer more than 0.5 mm away. Magnetic nanofibre mats might thus be useful for internal heat sealing applications, and potentially also for thermotherapy.

  16. Electrospun magnetic nanofibre mats – A new bondable biomaterial using remotely activated magnetic heating

    A solvothermal process was adopted to produce hydrophilic magnetite (Fe3O4) nanoparticles which were subsequently emulsified with a chloroform/methanol (70/30 v/v) solution of poly(caprolactone) (PCL) and then electrospun into a 0.2 mm thick PCL mat. The magnetic heating of the mats at a field amplitude of 25 kA/m and frequency of 400 kHz exhibited promising efficiency for magnetic hyperthermia, with a specific absorption rate of about 40 W/g for the magnetic mat. The produced heat was used to melt the magnetic mat onto the surrounding non-magnetic polymer mat from within, without destroying the nanostructure of the non-magnetic polymer more than 0.5 mm away. Magnetic nanofibre mats might thus be useful for internal heat sealing applications, and potentially also for thermotherapy

  17. De Novo Kidney Regeneration with Stem Cells

    Shinya Yokote

    2012-01-01

    Full Text Available Recent studies have reported on techniques to mobilize and activate endogenous stem-cells in injured kidneys or to introduce exogenous stem cells for tissue repair. Despite many recent advantages in renal regenerative therapy, chronic kidney disease (CKD remains a major cause of morbidity and mortality and the number of CKD patients has been increasing. When the sophisticated structure of the kidneys is totally disrupted by end stage renal disease (ESRD, traditional stem cell-based therapy is unable to completely regenerate the damaged tissue. This suggests that whole organ regeneration may be a promising therapeutic approach to alleviate patients with uncured CKD. We summarize here the potential of stem-cell-based therapy for injured tissue repair and de novo whole kidney regeneration. In addition, we describe the hurdles that must be overcome and possible applications of this approach in kidney regeneration.

  18. Modulation of cortical oscillatory activity during transcranial magnetic stimulation.

    Brignani, Debora; Manganotti, Paolo; Rossini, Paolo M; Miniussi, Carlo

    2008-05-01

    Transcranial magnetic stimulation (TMS) can transiently modulate cortical excitability, with a net effect depending on the stimulation frequency ( or =5 Hz facilitation, at least for the motor cortex). This possibility has generated interest in experiments aiming to improve deficits in clinical settings, as well as deficits in the cognitive domain. The aim of the present study was to investigate the on-line effects of low frequency (1 Hz) TMS on the EEG oscillatory activity in the healthy human brain, focusing particularly on the outcome of these modulatory effects in relation to the duration of the TMS stimulation. To this end, we used the event-related desynchronization/synchronization (ERD/ERS) approach to determine the patterns of oscillatory activity during two consecutive trains of sham and real TMS. Each train of stimulation was delivered to the left primary motor cortex (MI) of healthy subjects over a period of 10 min, while EEG rhythms were simultaneously recorded. Results indicated that TMS induced an increase in the power of brain rhythms that was related to the period of the stimulation, i.e. the synchronization of the alpha band increased with the duration of the stimulation, and this increase was inversely correlated with motor-evoked potentials (MEPs) amplitude. In conclusion, low frequency TMS over primary motor cortex induces a synchronization of the background oscillatory activity on the stimulated region. This induced modulation in brain oscillations seems to increase coherently with the duration of stimulation, suggesting that TMS effects may involve short-term modification of the neural circuitry sustaining MEPs characteristics. PMID:17557296

  19. Significance of magnetic resonance imaging for early rheumatoid arthritis activity

    E Y Pogozeva

    2009-01-01

    Full Text Available Objective. To assess possibility of magnetic resonance image (MRI application for rheu- matoid arthritis (RA activity and severity assessment.Material and methods. 100 pts with RA who fulfilled the 1987 ACR criteria with disease duration less than 12 months were included. Standard clinical examination with evaluation of tender and swollen joint counts, acute phase markers, hand and foot X-ray and hand MRI with 0,2 T Artoscan apparatus (ESAOTE Biomedica, Italy were performed.Results. MRI showed hand joint synovitis in 94,5%, erosions – in 67,3% of cases. X-ray examination revealed erosions in only 20,8% of pts. Localization of erosions revealed by X-ray and MRI coincided in 36,4% of cases and in 61,8% of pts erosions were detected only by MRI. MRI confirmed clinical conclusion about presence or absence of metacarpophalangeal and wrist joint synovitis in 64,5% and 74,5% of cases respectively. In8,2% and 21,8% MRI revealed signs of synovitis in clinically intact joints. MRI synovitis score correlated with clinical and laboratory measures of disease activity – DAS 28 (r=0,37, p=0,001, CRP(r=0,30, p=0,001, ESR (r=0,42, p=0,001, HAQ (r=0,24, p=0,001. Weak correlation was revealed between ESR and presence of erosions (r=0,29, CRP, ESR and MRI signs of bone marrow edema (r=0,27, p=0,005 and r=0,29, p=0,002 respectively. Relationship between laboratory and clinical features was weaker and referred only to CRP level and swollen joint count (p=0,05.Conclusion. MRI signs may be used as additional and independent measures of inflammatory activity (particularly synovitis score and severity of RA

  20. A tunnel regenerated coupled multi-active-region large optical cavity laser with a high quality beam

    Cui Bi-Feng; Guo Wei-Ling; Du Xiao-Dong; Li Jian-Jun; Zou De-Shu; Shen Guang-Di

    2012-01-01

    A novel coupled multi-active-region large optical cavity structure cascaded by a tunnel junction is proposed to solve the problems of facet catastrophic optical damage (COD) and the large vertical divergence caused by the thin emitting area in conventional laser diodes.For a laser with three active regions,a slope efficiency as high as 1.49 W/A,a vertical divergence angle of 17.4°,and a threshold current density of 271 A/cm2 are achieved.By optimizing the structural parameters,the beam quality is greatly improved,and the level of the COD power increases by more than two times compared with that of the conventional laser.

  1. Strategies for lung regeneration

    Thomas H. Petersen

    2011-05-01

    Full Text Available Due to the limited ability of the adult lung to regenerate and the frequency of lung disease, the lung is a tissue that can especially benefit from regenerative medicine. Prospects for lung regeneration have made great strides in the past year. In this review, we summarize recent progress and key challenges for approaches in lung regenerative medicine. With a focus on the matrix components critical for the development of regenerative lung tissues, we discuss possible cell sources for lung regeneration, key matrix effects on cell repopulation, and physical stimuli that will aid in the growth of lung tissues in vitro.

  2. Magnetic cooling at Risoe DTU

    Nielsen, Kaspar Kirstein; Bjørk, Rasmus; Jensen, Jesper Buch;

    2009-01-01

    , 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 DTU with emphasis on the numerical modeling of an existing AMR test machine. A 2D numerical heat......-transfer and fluid-flow model that represents the experimental setup is presented. Experimental data of both no-heat load and heat load situations are compared to the model. Moreover, results from the numerical modeling of the permanent magnet design used in the system are presented.......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...

  3. The combined removal of methyl mercaptan and hydrogen sulfide via an electro-reactor process using a low concentration of continuously regenerable Ag(II) active catalyst

    Highlights: → Simultaneous removal of H2S and CH3SH was achieved at electro-reactor. → Active catalyst Ag(II) perpetually regenerated in HNO3 medium by electrochemical cell. → CH3SH destruction follows two reaction pathways. → H2S induced destruction of CH3SH has identified. → Low concentration of active Ag(II) (12.5 x 10-4 mol L-1) is enough for complete destruction. - Abstract: In this study, an electrocatalytic wet scrubbing process was developed for the simultaneous removal of synthetic odorous gases namely, methyl mercaptan (CH3SH) and hydrogen sulfide (H2S). The initial process consists of the absorption of CH3SH and H2S gases by an absorbing solution, followed by their mediated electrochemical oxidation using a low concentration of active Ag(II) in 6 M HNO3. Experiments were conducted under different reaction conditions, such as CH3SH and H2S loadings, active Ag(II) concentrations and molar flow rates. The cyclic voltammetry for the oxidation of CH3SH corroborated the electro-reactor results, in that the silver in the 6 M HNO3 reaction solution significantly influences the oxidation of CH3SH. At a low active Ag(II) concentration of 0.0012 M, the CH3SH removal experiments demonstrated that the CH3SH degradation was steady, with 100% removal at a CH3SH loading of 5 g m-3 h-1. The electro-reactor and cyclic voltammetry results indicated that the removal of H2S (100%) follows a mediated electrocatalytic oxidation reaction. The simultaneous removal of 100% of the CH3SH and H2S was achieved, even with a very low active Ag(II) concentration (0.0012 M), as a result of the high efficiency of the Ag(II). The parallel cyclic voltammetry results demonstrated that a process of simultaneous destruction of both CH3SH and H2S follows an H2S influenced mediated electrocatalytic oxidation. The use of a very low concentration of the Ag(II) mediator during the electro-reactor process is promising for the complete removal of CH3SH and H2S.

  4. The Maximum Free Magnetic Energy Allowed in a Solar Active Region

    Moore, Ronald L.; Falconer, David A.

    2009-01-01

    Two whole-active-region magnetic quantities that can be measured from a line-of-sight magnetogram are (sup L) WL(sub SG), a gauge of the total free energy in an active region's magnetic field, and sup L(sub theta), a measure of the active region's total magnetic flux. From these two quantities measured from 1865 SOHO/MDI magnetograms that tracked 44 sunspot active regions across the 0.5 R(sub Sun) central disk, together with each active region's observed production of CMEs, X flares, and M flares, Falconer et al (2009, ApJ, submitted) found that (1) active regions have a maximum attainable free magnetic energy that increases with the magnetic size (sup L) (sub theta) of the active region, (2) in (Log (sup L)WL(sub SG), Log(sup L) theta) space, CME/flare-productive active regions are concentrated in a straight-line main sequence along which the free magnetic energy is near its upper limit, and (3) X and M flares are restricted to large active regions. Here, from (a) these results, (b) the observation that even the greatest X flares produce at most only subtle changes in active region magnetograms, and (c) measurements from MSFC vector magnetograms and from MDI line-of-sight magnetograms showing that practically all sunspot active regions have nearly the same area-averaged magnetic field strength: =- theta/A approximately equal to 300 G, where theta is the active region's total photospheric flux of field stronger than 100 G and A is the area of that flux, we infer that (1) the maximum allowed ratio of an active region's free magnetic energy to its potential-field energy is 1, and (2) any one CME/flare eruption releases no more than a small fraction (less than 10%) of the active region's free magnetic energy. This work was funded by NASA's Heliophysics Division and NSF's Division of Atmospheric Sciences.

  5. Ionospheric trough observation probability dependence on the season, local time, longitude and magnetic activity level

    Probability of different ionospheric trough observation for Kosmos satellite data (about 3000 circuits) is analysed. Trough appearance probability variations with the season, longitude, local time and magnetic activity are discriminated and investigated. It is shown that trough production probability depends on the magnetic activity and background ionization. The last is determined by illumination variations and neutral wind

  6. An Index (PC) Aimed at Monitoring the (P)olar (C)ap for Magnetic Activity

    National Oceanic and Atmospheric Administration, Department of Commerce — PC is an index for magnetic activity in the (P)olar (C)ap. It is based on data from a single nearpole station, and aimed to monitor the polar cap magnetic activity...

  7. Determination of the Topology Skeleton of Magnetic Fields in a Solar Active Region

    Hui Zhao; Jing-Xiu Wang; Jun Zhang; Chi-Jie Xiao; Hai-Min Wang

    2008-01-01

    Magnetic topology has been a key to the understanding of magnetic energy re-lease mechanism. Based on observed vector magnetograms, we have determined the three-dimensional (3D) topology skeleton of the magnetic fields in the active region NOAA 10720.The skeleton consists of six 3D magnetic nulls and a network of corresponding spines, fans,and null-null lines. For the first time, we have identified a spiral magnetic null in Sun's corona.The magnetic lines of force twisted around the spine of the null, forming a 'magnetic wreath'with excess of free magnetic energy and resembling observed brightening structures at extra-ultraviolet (EUV) wavebands. We found clear evidence of topology eruptions which are re-ferred to as catastrophic changes of topology skeleton associated with a coronal mass ejection(CME) and an explosive X-ray flare. These results shed new lights on the structural complex-ity and its role in explosive magnetic activity. The concept of flux rope has been widely used in modelling explosive magnetic activity, although their observational identity is rather ob-scure or, at least, lacking of necessary details up to date. We suggest that the magnetic wreath associated with the 3D spiral null is likely an important class of the physical entity of flux ropes.

  8. Enhancement of a magnetic nanofibrous composite scaffold for bone regeneration%磁性纳米纤维复合材料原位诱导体内成骨的研究

    许振; 孟洁; 张宇; 常晓; 边焱焱; 孔桦; 顾宁; 许海燕

    2011-01-01

    目的:研究一种新型顺磁性的纳米纤维复合支架γ-Fe2O3/nHAP/PDLLA在弱磁场下体内诱导新骨形成的功效.方法:纳米纤维复合材料支架通过电纺丝方法制成,支架内部的微观结构用扫描电镜(SEM)进行表征.将支架植入兔横突根部骨缺损处并在12周后处死动物,应用组织学方法研究支架在动物体内原位诱导新骨形成和胶原蛋白沉积的情况.结果:与对照的nHAP/PDLLA纳米纤维支架相比,磁性纳米纤维复合支架上有更多的Ⅰ型胶原沉积,新骨的生成量也明显增加.结论:磁性纳米纤维复合支架能够促进骨缺损部位的新骨生成,在引导骨组织再生与修复方面具有应用潜能.%Objective: To investigate the function of inducing bone regeneration of a novel paramagnetic nanofibrous composite scaffold of γ-Fe2O3/nHAP/PDLLA in vivo under a weak applied magnetic field.Methods: The scaffold was fabricated with the composite by electrospinning technique.The microstructure of the scaffold was characterized by scanning electron microscopy.The scaffold was implanted in defects at the root segment of the lumbar transverse process on a rabbit model.Bone tissue samples were collected after 12 weeks of implant surgery.New bone formation in the defects was assessed using histological analysis in reference to a control nanofibrous composite of nHAP/PDLLA.Deposition of type Ⅰ collagen fibers were examined by Sirius red staining.Results: There was new bone formation observed in the scaffold.Type Ⅰ collagen was deposited abundantly on the scaffold.Together all, the bone regeneration was enhanced obviously in comparison with that induced by control scaffold of nHAP/PDLLA.Conclusion: The scaffold of γ-Fe2O3/nHAP/PDLLA enhanced osteogenesis under a weak static magnetic field, and exhibited promising potential for use in bone repair.

  9. Optimization of Regenerators for AMRR Systems

    Nellis, Gregory [University of Wisconsin, Madison, WI (United States); Klein, Sanford [University of Wisconsin, Madison, WI (United States); Brey, William [University of Wisconsin, Madison, WI (United States); Moine, Alexandra [University of Wisconsin, Madison, WI (United States); Nielson, Kaspar [University of Wisconsin, Madison, WI (United States)

    2015-06-18

    Active Magnetic Regenerative Refrigeration (AMRR) systems have no direct global warming potential or ozone depletion potential and hold the potential for providing refrigeration with efficiencies that are equal to or greater than the vapor compression systems used today. The work carried out in this project has developed and improved modeling tools that can be used to optimize and evaluate the magnetocaloric materials and geometric structure of the regenerator beds required for AMRR Systems. There has been an explosion in the development of magnetocaloric materials for AMRR systems over the past few decades. The most attractive materials, based on the magnitude of the measured magnetocaloric effect, tend to also have large amounts of hysteresis. This project has provided for the first time a thermodynamically consistent method for evaluating these hysteretic materials in the context of an AMRR cycle. An additional, practical challenge that has been identified for AMRR systems is related to the participation of the regenerator wall in the cyclic process. The impact of housing heat capacity on both passive and active regenerative systems has been studied and clarified within this project. This report is divided into two parts corresponding to these two efforts. Part 1 describes the work related to modeling magnetic hysteresis while Part 2 discusses the modeling of the heat capacity of the housing. A key outcome of this project is the development of a publically available modeling tool that allows researchers to identify a truly optimal magnetocaloric refrigerant. Typically, the refrigeration potential of a magnetocaloric material is judged entirely based on the magnitude of the magnetocaloric effect and other properties of the material that are deemed unimportant. This project has shown that a material with a large magnetocaloric effect (as evidenced, for example, by a large adiabatic temperature change) may not be optimal when it is accompanied by a large hysteresis

  10. Magnetic graphene oxide-polystyrene and magnetic activated carbon-polystyrene nanocomposites as sorbents for bisphenol A.

    Rekos, Kyriazis; Kampouraki, Zoi Christina; Samanidou, Victoria; Deliyanni, Eleni

    2016-04-01

    Magnetic graphene oxide-polystyrene and magnetic activated carbon-polystyrene nanocomposites as sorbents for bisphenol A. Kyriazis Rekos1, Zoi Christina Kampouraki1, Victoria Samanidou2, Eleni Deliyanni1 1 Laboratory of General and Inorganic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece 2 Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece The aim of this work was to prepare and characterize novel composites of magnetic activated carbon or magnetic graphene oxide with polystyrene (GO/PSm), through one step simple and effective route. Μagnetite nanoparticles, prepared in the laboratory, were dispersed in the presence of activated carbon (C) or graphene oxide (GO) in a polystyrene (PS) solution in dimethylformamide, at elevated temperature, for the fabrication of the magnetite-Carbon-PS (C-PSm) and magnetite- Graphene Oxide-PS (GO-PSm) hybrid-nanoparticles. For comparison, C-PS and GO-PS composites were also prepared in the same route. The nanocomposites were tested for their sorption ability for an endocrine disruptor, bisphenol A. The effect of solution pH, initial concentration, contact time and temperature were examined. The magnetic graphite oxide-polystyrene presented higher adsorption capacity (100 mg/g) than the non magnetic composites (70 mg/g), as well as than initial graphite oxide (20 mg/g). FTIR, XRD, BET, TGA, VSM and SEM were performed in order to investigate the role of the PS on the better adsorption performance of the mGO-PS nanocomposites. The characterization with these techniques revealed the possible interactions of the surface functional groups of activated carbon and/or graphite oxide with polystyrene that resulted in the better performance of the magnetic nanocomposites for bisphenol A adsorption.

  11. MAGNET

    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...

  12. Effects of o-aminoazotoluene on liver regeneration and p53 activation in mice susceptible and resistant to hepatocarcinogenesis

    The susceptibility to hepatocellular carcinoma (HCC) varies greatly within human populations in response to environmental risk agents. The mechanisms underlying differential susceptibility are still largely unknown and need to be clarified to improve HCC chemoprevention and therapeutic treatment. Inbred rodent strains with established predispositions for hepatocarcinogenesis offer the opportunity to identify intrinsic susceptibility and resistance factors. Previously, we have characterized mouse strains showing differential susceptibility to o-aminoazotoluene (OAT) and established that susceptibility does not result from OAT metabolism or genotoxicity in the livers of resistant and susceptible mice. In this study we have found that OAT differently affects hepatocyte proliferation in mice after partial hepatectomy (PH). OAT inhibited hepatocyte proliferation by 60-80% in the livers of susceptible mice, whereas resistant mice showed less than 15% inhibition. The inhibition resulted in significant delay of hepatic mass recovery in susceptible mice. OAT induced p53 stabilization and transcriptional activation in response to carcinogen treatment to the same degree in both, susceptible and resistant mice. Taken together, our data support inhibition of hepatocyte proliferation as a major cause for increased mouse susceptibility to hepatocarcinogenesis, and acceleration of functional liver recovery may offer a way to increase resistance to hepatic neoplasms. These results may have relevance to clinical observations of HCCs and implications for HCC chemoprevention and treatment

  13. Treadmill Training Promotes Axon Regeneration in Injured Peripheral Nerves

    Sabatier, Manning J.; Redmon, Natalie; Schwartz, Gail; English, Arthur W.

    2008-01-01

    Physical activity after spinal cord injury promotes improvements in motor function, but its effects following peripheral nerve injury are less clear. Although axons in peripheral nerves are known to regenerate better than those in the CNS, methods of accelerating regeneration are needed due to the slow overall rate of growth. Therefore we studied the effect of two weeks of treadmill locomotion on the growth of regenerating axons in peripheral nerves following injury. The common fibular nerves...

  14. Hedgehog Signaling Is Required for Effective Regeneration of Exocrine Pancreas

    Fendrich, Volker; Esni, Farzad; GARAY, MARIA VERONICA R.; Feldmann, Georg; Habbe, Nils; Jensen, Jan Nygaard; Dor, Yuval; Stoffers, Doris; Jensen, Jan; Leach, Steven D.; Maitra, Anirban

    2008-01-01

    Although both endocrine and the exocrine pancreas display a significant capacity for tissue regeneration and renewal, the existence of progenitor cells in the adult pancreas remains uncertain. Using a model of cerulein-mediated injury and repair, we demonstrate that mature exocrine cells, defined by expression of an Elastase1 promoter, actively contribute to regenerating pancreatic epithelium through formation of metaplastic ductal intermediates. Acinar cell regeneration is associated with ac...

  15. Magnetic bearing momentum wheels with magnetic gimballing capability for 3-axis active attitude control and energy storage

    Sindlinger, R. S.

    1977-01-01

    Magnetic bearings used for the suspension of momentum wheels provide conclusive advantages: the low friction torques and the absence of abrasion allow the realization of lightweight high speed wheels with high angular momentum and energy storage capacity and virtually unlimited lifetime. The use of actively controlled bearings provides a magnetic gimballing capability by applying the external signals to the two servo loops controlling the rotational degrees of freedom. Thus, an attitude control system can be realized by using only one rotating mass for 3-axis active satellite stabilization.

  16. Silymarin Accelerates Liver Regeneration after Partial Hepatectomy

    Jia-Ping Wu

    2015-01-01

    Full Text Available Partial hepatectomy (PHx is a liver regeneration physiological response induced to maintain homeostasis. Liver regeneration evolved presumably to protect wild animals from catastrophic liver loss caused by toxins or tissue injury. Silymarin (Sm ability to stimulate liver regeneration has been an object of curiosity for many years. Silymarin has been investigated for use as an antioxidant and anticarcinogen. However, its use as a supportive treatment for liver damage is elusive. In this study, we fed silymarin (Sm, 25 mg/kg to male Sprague-Dawley rats for 7 weeks. Surgical 2/3 PHx was then conducted on the rats at 6 hrs, 24 hrs, and 72 hrs. Western blot and RT-PCR were conducted to detect the cell cycle activities and silymarin effects on hepatic regeneration. The results showed that silymarin enhanced liver regeneration by accelerating the cell cycle in PHx liver. Silymarin led to increased G1 phase (cyclin D1/pRb, S phase (cyclin E/E2F, G2 phase (cyclin B, and M phase (cyclin A protein and mRNA at 6 hrs, 24 hrs, and 72 hrs PHx. HGF, TGFα, and TGFβ1 growth factor expressions were also enhanced. We suggest that silymarin plays a crucial role in accelerated liver regeneration after PHx.

  17. Activation of satellite cells and the regeneration of human skeletal muscle are expedited by ingestion of nonsteroidal anti-inflammatory medication

    Mackey, Abigail L; Rasmussen, Lotte K; Kadi, Fawzi; Schjerling, Peter; Helmark, Ida C; Ponsot, Elodie; Aagaard, Per; Durigan, João Luiz Q; Kjaer, Michael

    2016-01-01

    With this study we investigated the role of nonsteroidal anti-inflammatory drugs (NSAIDs) in human skeletal muscle regeneration. Young men ingested NSAID [1200 mg/d ibuprofen (IBU)] or placebo (PLA) daily for 2 wk before and 4 wk after an electrical stimulation-induced injury to the leg extensor...... muscles of one leg. Muscle biopsies were collected from the vastus lateralis muscles before and after stimulation (2.5 h and 2, 7, and 30 d) and were assessed for satellite cells and regeneration by immunohistochemistry and real-time RT-PCR, and we also measured telomere length. After injury, and compared...

  18. Expression and localization of regenerating gene I in a rat liver regeneration model

    Regenerating gene (Reg) I has been identified as a regenerative/proliferative factor for pancreatic islet cells. We examined Reg I expression in the regenerating liver of a rat model that had been administered 2-acetylaminofluorene and treated with 70% partial hepatectomy (2-AAF/PH model), where hepatocyte and cholangiocyte proliferation was suppressed and the hepatic stem cells and/or hepatic progenitor cells were activated. In a detailed time course study of activation of hepatic stem cells in the 2-AAF/PH model, utilizing immunofluorescence staining with antibodies of Reg I and other cell-type-specific markers, we found that Reg I-expressing cells are present in the bile ductules and increased during regeneration. Reg I-expressing cells were colocalized with CK19, OV6, and AFP. These results demonstrate that Reg I is significantly upregulated in the liver of the 2-AAF/PH rat model, accompanied by the formation of bile ductules during liver regeneration.

  19. Research on Attitude System of Active Magnetic Control Small Satellite

    Zhaowei, Sun; Di, Yang

    1998-01-01

    When enter orbit, small satellite often tumble as a result of disturbance. How to capture it promptly with finite magnetic torque is an important problem. Because of the coupling of dynamics and control, the small satellite control system is a nonlinear attitude control system with bounds. For high direction and steady precision, an effective method must be found. In this paper, combining with the bound conditions of magnetic torque, two methods are researched. The first is energy method. It ...

  20. Dependence of Stellar Magnetic Activity Cycles on Rotational Period in a Nonlinear Solar-type Dynamo

    Pipin, V. V.; Kosovichev, A. G.

    2016-06-01

    We study the turbulent generation of large-scale magnetic fields using nonlinear dynamo models for solar-type stars in the range of rotational periods from 14 to 30 days. Our models take into account nonlinear effects of dynamical quenching of magnetic helicity, and escape of magnetic field from the dynamo region due to magnetic buoyancy. The results show that the observed correlation between the period of rotation and the duration of activity cycles can be explained in the framework of a distributed dynamo model with a dynamical magnetic feedback acting on the turbulent generation from either magnetic buoyancy or magnetic helicity. We discuss implications of our findings for the understanding of dynamo processes operating in solar-like stars.

  1. Dependence of stellar magnetic activity cycles on rotational period in nonlinear solar-type dynamo

    Pipin, Valery

    2016-01-01

    We study turbulent generation of large-scale magnetic fields using nonlinear dynamo models for solar-type stars in the range of rotational periods from 14 to 30 days. Our models take into account non-linear effects of dynamical quenching of magnetic helicity, and escape of magnetic field from the dynamo region due to magnetic buoyancy. The results show that the observed correlation between the period of rotation and the duration of activity cycles can be explained in the framework of a distributed dynamo model with a dynamical magnetic feedback acting on the turbulent generation either from magnetic buoyancy or magnetic helicity. We discuss implications of our findings for the understanding of dynamo processes operating in solar-like stars.

  2. Differential activation of nerve fibers with magnetic stimulation in humans

    Olree Kenneth S

    2006-07-01

    Full Text Available Abstract Background Earlier observations in our lab had indicated that large, time-varying magnetic fields could elicit action potentials that travel in only one direction in at least some of the myelinated axons in peripheral nerves. The objective of this study was to collect quantitative evidence for magnetically induced unidirectional action potentials in peripheral nerves of human subjects. A magnetic coil was maneuvered to a location on the upper arm where physical effects consistent with the creation of unidirectional action potentials were observed. Electromyographic (EMG and somatosensory evoked potential (SEP recordings were then made from a total of 20 subjects during stimulation with the magnetic coil. Results The relative amplitudes of the EMG and SEP signals changed oppositely when the current direction in the magnetic coil was reversed. This effect was consistent with current direction in the coil relative to the arm for all subjects. Conclusion A differential evocation of motor and sensory fibers was demonstrated and indicates that it may be possible to induce unidirectional action potentials in myelinated peripheral nerve fibers with magnetic stimulation.

  3. Flare activity, sunspot motions, and the evolution of vector magnetic fields in Hale region 17244

    Neidig, Donald F.; Hagyard, Mona J.; Machado, Marcos E.; Smith, Jesse B., Jr.

    1986-01-01

    The magnetic and dynamical circumstances leading to the 1B/M4 flare of November 5, 1980 are studied, and a strong association is found between the buildup of magnetic shear and the onset of flare activity within the active region. The development of shear, as observed directly in vector magnetograms, is consistent in detail with the dynamical history of the active region and identifies the precise location of the optical and hard-X-ray kernels of the flare emission.

  4. Irradiation inhibits the regeneration of aneurogenic limbs. [X radiation

    Wallace, H.; Maden, M.

    1976-03-01

    The developing arms of axolotl larvae from the 2-digit stage onward and the aneurogenic arms of surgically denervated larvae maintained in parabiosis are able to regenerate after amputation. Such regeneration is uniformly inhibited by local irradiation of the arm, whether innervated or not. This demonstration refutes a recent hypothesis that x-rays interfere with a special activity of nerves required for regeneration, and supports the earlier concept that x-rays act directly on those cells which must proliferate to form the regenerated tissues.

  5. Regeneration of guinea PIG facial nerve: the effect of hypergravity

    Rosenzweig, E.; Horodiceanu, E.; Ishay, J. S.

    Exposure to moderate hypergravity improves the regenerative capacity of sectioned guinea-pig facial nerve. The improvement in regeneration is tri-directional as follows: a) an average 1.7 fold increase in rate of regeneration in guinea pigs subjected to hypergravity; b) a 25% enhancement of facial muscle activity following the exposure to hypergravity; and c) improvement in the quality of regeneration from an esthetic standpoint. A good correlation was recorded between the histological structure of the severed nerve at the end of the regeneration and the clinical results.

  6. Thermally-Activated Magnetic Reversal Induced by a Spin-Polarized Current

    Myers, E. B.; Albert, F. J.; Saneky, J. C.; Bonet, E.; Buhrman, R. A.; Ralph, D. C.

    2002-01-01

    We have measured the statistical properties of magnetic reversal in nanomagnets driven by a spin-polarized current. Like reversal induced by a magnetic field, spin-transfer-driven reversal near room temperature exhibits the properties of thermally-activated escape over an effective barrier. However, the spin-transfer effect produces qualitatively different behaviors than an applied magnetic field. We discuss an effective current vs. field phase diagram. If the current and field are tuned so t...

  7. Toward Modelling Topsoil Magnetic Susceptibility for Demining Activities

    Hannam, J. A.; Dearing, J. A.

    2003-12-01

    The Landmine Monitor estimates that landmines cause up to 20,000 fatalities and casualties worldwide every year, in over 100 countries affected by landmine contamination. Although detection technologies have become more sophisticated, the metal detector still remains the most widely employed detection system in landmine affected regions. With increased use of minimum metal mines, the performance and sensitivity of metal detectors are increasingly challenged. In addition to mine constituents, depth of burial and orientation, soil properties significantly affect metal detection capabilities. Soils with high magnetic susceptibility, in particular those dominated by viscous components, interfere with the response signal in both frequency and time domain metal detection systems. Using Bosnia and Herzegovina (BiH) as a pilot region, we created an expert system to predict topsoil susceptibility from environmental information within a SOTER data base. Initially, the knowledge base is constructed from published relationships of environmental parameters and magnetic susceptibility and knowledge of experts in the field of soil magnetism. The knowledge base is underpinned by environmental conditions that are known to enhance or reduce magnetic susceptibility in topsoils. Where semi-quantitative data exists, transfer-functions are used to provide first approximations of susceptibility classes and offer a basis for a probability score for the susceptibility class. As a first approximation, susceptibility values are categorized into five continuous classes delimited by published magnetic susceptibility ranges in topsoils. The predicted susceptibility maps result in regional contrasts, delineated by the spatial scale of the environmental information. Further development of the model using a Baysean rule-based system with fuzzy boundaries is anticipated. Validation of the model is proposed using archived soil survey samples from BiH. In addition to providing essential data for

  8. Numerical modelling and analysis of a room temperature magnetic refrigeration system

    Petersen, Thomas Frank

    This thesis presents a two-dimensional mathematical model of an Active Magnetic Regenerator (AMR) system which is used for magnetic refrigeration at room temperature. The purpose of the model is to simulate a laboratory-scale AMR constructed at Risø National Laboratory. The AMR model geometry...... comprises a regenerator made of parallel plates, which are separated by channels of a heat transfer fluid. The time-dependent model solves the momentum and continuity equations of the flow of the heat transfer fluid and the coupled energy equations of the heat transfer in the regenerator and the fluid. The...... AMR performs a cyclic process, and to simulate the AMR refrigeration cycle the model starts from an initial temperature distribution in the regenerator and fluid channel and takes time steps forward in time until the cyclical steady-state is obtained. The model can therefore be used to study both...

  9. Changes seen on magnetic resonance imaging in the intervertebral disc space after chemonucleosis: a hypothesis concerning regeneration of the disc after chemonucleosis

    Kato, F.; Mimatsu, K.; Kawakami, N.; Miura, T. (Dept. of Orthopaedic Surgery, School of Medicine, Nagoya Univ. (Japan))

    1992-08-01

    Measurements of the intervertebral disc space were made by magnetic resonance imaging and plain film examinations over a period of 2 years in 26 patients who had undergone chemonucleolysis. The height of the posterior portion of the disc decreased after 3 months and never recovered; the height of the anterior portion also decreased but recovered slightly over the same period. The angle of lordosis and the range of motion in the treated segment were decreased, but recovered. Marked decrease in signal from the disc was observed after 2 weeks which did not recover till 2 years after chemonucleolysis. We suspect that the disc degenerated markedly after chemonucleolysis and changed into a type of scar tissue, maturation of which could stabilize the affected segment. (orig.).

  10. Changes seen on magnetic resonance imaging in the intervertebral disc space after chemonucleosis: a hypothesis concerning regeneration of the disc after chemonucleosis

    Measurements of the intervertebral disc space were made by magnetic resonance imaging and plain film examinations over a period of 2 years in 26 patients who had undergone chemonucleolysis. The height of the posterior portion of the disc decreased after 3 months and never recovered; the height of the anterior portion also decreased but recovered slightly over the same period. The angle of lordosis and the range of motion in the treated segment were decreased, but recovered. Marked decrease in signal from the disc was observed after 2 weeks which did not recover till 2 years after chemonucleolysis. We suspect that the disc degenerated markedly after chemonucleolysis and changed into a type of scar tissue, maturation of which could stabilize the affected segment. (orig.)

  11. Active magnetic bearings: As applied to centrifugal pumps

    Nelik, Lev; Cooper, Paul; Jones, Graham; Galecki, Dennis; Pinckney, Frank; Kirk, Gordon

    1992-01-01

    Application of magnetic bearings to boiler feed pumps presents various attractive features, such as longer bearing life, lower maintenance costs, and improved operability through control of the rotordynamics. Magnetic bearings were fitted to an eight-stage, 600 hp boiler feed pump, which generates 2600 ft of heat at 680 gpm and 3560 rpm. In addition to the varied and severe operating environment in steady state operation of this pump in a power plant, it is also subjected to transient loads during frequent starts and stops. These loads can now be measured by the in-built instrumentation of the magnetic bearings. Following site installation, a follow-up bearing tune-up was performed, and pump transient response testing was conducted. The bearing response was completely satisfactory, ensuring trouble-free pump operation even in the range of reduced load. The experience gained so far through design and testing proves feasibility of magnetic bearings for boiler feed pumps, which sets the stage for application of even higher energy centrifugal pumps equipped with magnetic bearings.

  12. Time scheduling of magnetic surveys in mid-latitudes with respect to forecasting geomagnetic activity

    Hejda, Pavel; Bochníček, Josef; Horáček, Josef; Nejedlá, Jaroslava

    2006-01-01

    Roč. 58, č. 6 (2006), s. 735-740. ISSN 1343-8832 R&D Projects: GA AV ČR IAA3012105 Institutional research plan: CEZ:AV0Z30120515 Keywords : magnetic surveys * repeat stations * geomagnetic activity Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 0.954, year: 2006

  13. Control of Active Axial Magnetic Bearings for Flywheel-based Energy Storage System

    Morís Gómez, Juan

    2014-01-01

    This thesis deals with the design and implementation of the control system for a Flywheel-based Energy Storage System (FESS) with active magnetic bearings. The thesis focuses on the construction of realistic model of the system according to experimental tests. The simulation model will be used to control the thrust magnetic bearings in order to withstand the flywheel in levitation.

  14. Employing Magnetic Levitation to Monitor Reaction Kinetics and Measure Activation Energy

    Benz, Lauren; Cesafsky, Karen E.; Le, Tran; Park, Aileen; Malicky, David

    2012-01-01

    This article describes a simple and inexpensive undergraduate-level kinetics experiment that uses magnetic levitation to monitor the progress and determine the activation energy of a condensation reaction on a polymeric solid support. The method employs a cuvette filled with a paramagnetic solution positioned between two strong magnets. The…

  15. Iodine laser with repeated use of a regenerated mixture

    Gavrilina, L.K.; Katulin, V.A.; Korzhavina, N.N.; Leonov, Y.S.; Morozov, Y.I.; Nosach, V.Y.; Petrov, A.L.

    1979-07-01

    An iodine laser is described, pumped by radiation from an open high-current discharge and having a system for regenerating the spent mixture. The regeneration system makes it possible to reuse the SF/sub 6/ buffer gas many times, and it can be included in a closed cycle for replacing the active mixture in the laser chamber with a multiple discharge system.

  16. Magnetically Active and Coated Gadolinium-Filled Carbon Nanotubes

    Fidiani, Elok

    2013-08-15

    Gd-filled carbon nanotubes (which include the so-called gadonanotubes(1)) have been attracting much interest due to their potential use in medical diagnostic applications. In the present work, a vacuum filling method was performed to confine gadolinium(III) iodide in carbon nanotubes (CNTs). Filling yields in excess of 50% were obtained. Cleaning and dosing of the external walls was undertaken, as well as the study of the filled CNT magnetic properties. Overall, we found that the encapsulating procedure can lead to reduction of the lanthanide metal and induce disorder in the initial GdI3-type structure. Notwithstanding, the magnetic response of the material is not compromised, retaining a strong paramagnetic response and an effective magnetic moment of similar to 6 mu B. Our results may entice further investigation into whether an analogous Gd3+ to Gd2+ reduction takes place in other Gd-filled CNT systems.

  17. TRANSIENT TEMPERATURE FIELD IN ACTIVE THRUST MAGNETIC BEARING

    Sun Shouqun; Geng Haipeng; Guo Keqian

    2005-01-01

    A transient temperature field model in a thrust magnetic bearing is built in which the heat resources come mainly from the eddy-current loss of solid cores and the copper loss of coils. The transient temperature field, system temperature rise and the thermo-equilibrium state during the rotor starting-up are calculated considering only the copper loss and the eddy-current loss. The numerical results indicate that the temperatures in coils and in magnets rise rapidly, their thermo-equilibrium states are formed within a short time. The temperatures in a thrust-disk and in a rotor rise slowly, their thermo-equilibrium states are formed after a long period time. The temperatures of the thrust-disk and the rotor are far higher than the temperatures of coils and/or magnets after the thermo-equilibrium state has come into being.

  18. Magnetic resonance imaging as a tool for extravehicular activity analysis

    Dickenson, R.; Lorenz, C.; Peterson, S.; Strauss, A.; Main, J.

    1992-01-01

    The purpose of this research is to examine the value of magnetic resonance imaging (MRI) as a means of conducting kinematic studies of the hand for the purpose of EVA capability enhancement. After imaging the subject hand using a magnetic resonance scanner, the resulting 2D slices were reconstructed into a 3D model of the proximal phalanx of the left hand. Using the coordinates of several landmark positions, one is then able to decompose the motion of the rigid body. MRI offers highly accurate measurements due to its tomographic nature without the problems associated with other imaging modalities for in vivo studies.

  19. Regeneration under shelterwood

    Erefur, Charlotta

    2007-01-01

    The objectives of this work were to quantify the effects of stand stem density (SSD), orientation and distance with respect to shelter tree, and fertilisation on the establishment of Pinus sylvestris L. and Picea abies (L.) Karst. regenerated by direct seeding and planting at different soil preparations. The field experiments were performed on South (64°14ʼN, 19°46ʼE, 225 m a.s.l.) and North (64°09ʼN, 19°36ʼE, 274 m a.s.l.) slopes in boreal Sweden. Regeneration and early growth in three stand ...

  20. Auroral Electrojet Index Designed to Provide a Global Measure, Hourly Intervals, of Auroral Zone Magnetic Activity

    National Oceanic and Atmospheric Administration, Department of Commerce — The Auroral Electrojet (AE) index is designed to provide a global quantitative measure of auroral zone magnetic activity produced by enhanced ionospheric currents...

  1. Low-latitude coronal holes, decaying active regions and global coronal magnetic structure

    Petrie, Gordon

    2013-01-01

    We study the relationship between decaying active region magnetic fields, coronal holes and the global coronal magnetic structure using Global Oscillations Network Group (GONG) synoptic magnetograms, Solar Terrestrial RElations Observatory (STEREO) extreme ultra-violet (EUV) synoptic maps and coronal potential-field source-surface (PFSS) models. We analyze 14 decaying regions and associated coronal holes occurring between early 2007 and late 2010, four from cycle 23 and 10 from cycle 24. We investigate the relationship between asymmetries in active regions' positive and negative magnetic intensities, asymmetric magnetic decay rates, flux imbalances, global field structure and coronal hole formation. Whereas new emerging active regions caused changes in the large-scale coronal field, the coronal fields of the 14 decaying active regions only opened under the condition that the global coronal structure remained almost unchanged. This was because the dominant slowly-varying, low-order multipoles prevented opposin...

  2. Evaluating the effect of magnetocaloric properties on magnetic refrigeration performance

    Engelbrecht, Kurt; Bahl, Christian Robert Haffenden

    2010-01-01

    Active magnetic regenerator (AMR) refrigerators represent an alternative to vapor compression technology that relies on the magnetocaloric effect in a solid refrigerant. Magnetocaloric materials are in development and properties are reported regularly. Recently, there has been an emphasis on developing materials with a high entropy change with magnetization while placing lower emphasis on the adiabatic temperature change. This work uses model magnetocaloric materials and a numerical AMR model...

  3. Statistical study of free magnetic energy and flare productivity of solar active regions

    Photospheric vector magnetograms from the Helioseismic and Magnetic Imager on board the Solar Dynamic Observatory are utilized as the boundary conditions to extrapolate both nonlinear force-free and potential magnetic fields in solar corona. Based on the extrapolations, we are able to determine the free magnetic energy (FME) stored in active regions (ARs). Over 3000 vector magnetograms in 61 ARs were analyzed. We compare FME with the ARs' flare index (FI) and find that there is a weak correlation (<60%) between FME and FI. FME shows slightly improved flare predictability relative to the total unsigned magnetic flux of ARs in the following two aspects: (1) the flare productivity predicted by FME is higher than that predicted by magnetic flux and (2) the correlation between FI and FME is higher than that between FI and magnetic flux. However, this improvement is not significant enough to make a substantial difference in time-accumulated FI, rather than individual flare, predictions.

  4. Statistical study of free magnetic energy and flare productivity of solar active regions

    Su, J. T.; Jing, J.; Wang, S.; Wang, H. M. [Space Weather Research Laboratory, New Jersey Institute of Technology, University Heights, Newark, NJ 07102-1982 (United States); Wiegelmann, T., E-mail: sjt@bao.ac.cn [Max-Planck-Institut fur Sonnensystemforschung, Max-Planck-Strasse 2, D-37191 Katlenburg-Lindau (Germany)

    2014-06-20

    Photospheric vector magnetograms from the Helioseismic and Magnetic Imager on board the Solar Dynamic Observatory are utilized as the boundary conditions to extrapolate both nonlinear force-free and potential magnetic fields in solar corona. Based on the extrapolations, we are able to determine the free magnetic energy (FME) stored in active regions (ARs). Over 3000 vector magnetograms in 61 ARs were analyzed. We compare FME with the ARs' flare index (FI) and find that there is a weak correlation (<60%) between FME and FI. FME shows slightly improved flare predictability relative to the total unsigned magnetic flux of ARs in the following two aspects: (1) the flare productivity predicted by FME is higher than that predicted by magnetic flux and (2) the correlation between FI and FME is higher than that between FI and magnetic flux. However, this improvement is not significant enough to make a substantial difference in time-accumulated FI, rather than individual flare, predictions.

  5. Statistical study of free magnetic energy and flare productivity of solar active regions

    Su, J T; Wang, S; Wiegelmann, T; Wang, H M

    2014-01-01

    Photospheric vector magnetograms from Helioseismic and Magnetic Imager on board the Solar Dynamic Observatory are utilized as the boundary conditions to extrapolate both non-linear force-free and potential magnetic fields in solar corona. Based on the extrapolations, we are able to determine the free magnetic energy (FME) stored in active regions (ARs). Over 3000 vector magnetograms in 61 ARs were analyzed. We compare FME with ARs' flare index (FI) and find that there is a weak correlation ($<60\\%$) between FME and FI. FME shows slightly improved flare predictability relative to total unsigned magnetic flux of ARs in the following two aspects: (1) the flare productivity predicted by FME is higher than that predicted by magnetic flux and (2) the correlation between FI and FME is higher than that between FI and magnetic flux. However, this improvement is not significant enough to make a substantial difference in time-accumulated FI, rather than individual flare, predictions.

  6. Study of magnetic field expansion using a plasma generator for space radiation active protection

    JIA Xiang-Hong; JIA Shao-Xia; XU Feng; BAI Yan-Qiang; WAN Jun; LIU Hong-Tao; JIANG Rui

    2013-01-01

    There are many active protecting methods including Electrostatic Fields,Confined Magnetic Field,Unconfined Magnetic Field and Plasma Shielding etc.for defending the high-energy solar particle events (SPE) and Galactic Cosmic Rays (GCR) in deep space exploration.The concept of using cold plasma to expand a magnetic field is the best one of all possible methods so far.The magnetic field expansion caused by plasma can improve its protective efficiency of space particles.One kind of plasma generator has been developed and installed into the cylindrical permanent magnet in the eccentric.A plasma stream is produced using a helical-shaped antenna driven by a radio-frequency (RF) power supply of 13.56 MHz,which exits from both sides of the magnet and makes the magnetic field expand on one side.The discharging belts phenomenon is similar to the Earth's radiation belt,but the mechanism has yet to be understood.A magnetic probe is used to measure the magnetic field expansion distributions,and the results indicate that the magnetic field intensity increases under higher increments of the discharge power.

  7. Long-term variation in the Sun's activity caused by magnetic Rossby waves in the tachocline

    Zaqarashvili, T V; Hanslmeier, A; Carbonell, M; Ballester, J L; Gachechiladze, T; Usoskin, I G

    2015-01-01

    Long-term records of sunspot number and concentrations of cosmogenic radionuclides (10Be and 14C) on the Earth reveal the variation of the Sun's magnetic activity over hundreds and thousands of years. We identify several clear periods in sunspot, 10Be, and 14C data as 1000, 500, 350, 200 and 100 years. We found that the periods of the first five spherical harmonics of the slow magnetic Rossby mode in the presence of a steady toroidal magnetic field of 1200-1300 G in the lower tachocline are in perfect agreement with the time scales of observed variations. The steady toroidal magnetic field can be generated in the lower tachocline either due to the steady dynamo magnetic field for low magnetic diffusivity or due to the action of the latitudinal differential rotation on the weak poloidal primordial magnetic field, which penetrates from the radiative interior. The slow magnetic Rossby waves lead to variations of the steady toroidal magnetic field in the lower tachocline, which modulate the dynamo magnetic field ...

  8. Magnetic Nonpotentiality in Photospheric Active Regions as a Predictor of Solar Flares

    Yang, Xiao; Lin, GangHua; Zhang, Hongqi; Mao, Xinjie

    2013-01-01

    Based on several magnetic nonpotentiality parameters obtained from the vector photospheric active region magnetograms obtained with the Solar Magnetic Field Telescope at the Huairou Solar Observing Station over two solar cycles, a machine learning model has been constructed to predict the occurrence of flares in the corresponding active region within a certain time window. The Support Vector Classifier, a widely used general classifier, is applied to build and test the prediction models. Seve...

  9. Magnetic field changes activate the trigeminal brainstem complex in a migratory bird

    Heyers, Dominik; Zapka, Manuela; Hoffmeister, Mara; Wild, John Martin; Mouritsen, Henrik

    2010-01-01

    The upper beak of birds, which contains putative magnetosensory ferro-magnetic structures, is innervated by the ophthalmic branch of the trigeminal nerve (V1). However, because of the absence of replicable neurobiological evidence, a general acceptance of the involvement of the trigeminal nerve in magnetoreception is lacking in birds. Using an antibody to ZENK protein to indicate neuronal activation, we here document reliable magnetic activation of neurons in and near the principal (PrV) and ...

  10. Variability in foF2 at an equatorial station and the influence of magnetic activity

    Variability in foF2 is investigated for an equatorial station in the African region. Variability during the day time at high solar activity varies between 10 and 30 percent. It varies between 10 and 20 percent at high solar activity. Magnetic storms increase the variability at both solar activity periods. (author)

  11. Infection and Pulp Regeneration

    Sahng G. Kim

    2016-03-01

    Full Text Available The regeneration of the pulp-dentin complex has been a great challenge to both scientists and clinicians. Previous work has shown that the presence of prior infection may influence the characteristics of tissues formed in the root canal space after regenerative endodontic treatment. The formation of ectopic tissues such as periodontal ligament, bone, and cementum has been observed in the root canal space of immature necrotic teeth with apical periodontitis, while the regeneration of dentin and pulp has been identified in previously non-infected teeth. The current regenerative endodontic therapy utilizes disinfection protocols, which heavily rely on chemical irrigation using conventional disinfectants. From a microbiological point of view, the current protocols may not allow a sufficiently clean root canal microenvironment, which is critical for dentin and pulp regeneration. In this article, the significance of root canal disinfection in regenerating the pulp-dentin complex, the limitations of the current regenerative endodontic disinfection protocols, and advanced disinfection techniques designed to reduce the microorganisms and biofilms in chronic infection are discussed.

  12. The effects of clenbuterol on satellite cell activation and the regeneration of skeletal muscle: an autoradiographic and morphometric study of whole muscle transplants in mice.

    Roberts, P; McGeachie, J K

    1992-01-01

    The beta-2 agonist clenbuterol was tested for its effect on the proliferation of satellite cells in transplanted skeletal muscles. Using autoradiographic techniques it was found that satellite cells in clenbuterol treated transplants began proliferating earlier than in control animals. The effect of clenbuterol on the growth of regenerating muscle fibres was also examined using morphometric techniques, which manifested itself as hypertrophy of the fibres when compared with the controls.

  13. The evaluation of the activity of medicinal remedies of plant and animal origin on the regeneration of the earthworms’ tail segments

    Viktor Alexandrovich Bybin; Daevard Iosifovich Stom

    2015-01-01

    Now, in the global community there is enough hard recommendation to replace the vertebrate test animals into simpler organisms at the development, testing, and evaluation of the quality pharmaceuticals. The feature of planarian to regenerate in new individual planarian from a piece, which is only 1/7 of the original animal, allowed to create the alternative methods of testing of drugs, dietary supplements, water quality, influence of electromagnetic fields, and other radiations. The tests on ...

  14. Quantifying the Topology and Evolution of a Magnetic Flux Rope Associated with Multi-flare Activities

    Yang, Kai; Ding, M D

    2016-01-01

    Magnetic flux rope (MFR) plays an important role in solar activities. A quantitative assessment of the topology of an MFR and its evolution is crucial for a better understanding of the relationship between the MFR and the associated activities. In this paper, we investigate the magnetic field of active region 12017 from 2014 March 28 to 29, where 12 flares were triggered by the intermittent eruptions of a filament (either successful or confined). Using the vector magnetic field data from the Helioseismic and Magnetic Imager on board the \\textit{Solar Dynamics Observatory}, we calculate the magnetic energy and helicity injection in the active region, and extrapolate the 3D magnetic field with a nonlinear force-free field model. From the extrapolations, we find an MFR that is cospatial with the filament. We further determine the configuration of this MFR by a closed quasi-separatrix layer (QSL) around it. Then, we calculate the twist number and the magnetic helicity for the field lines composing the MFR. The re...

  15. Regenerated Fe is tasty!

    Nuester, J.; Twining, B. S.

    2012-12-01

    Bioavailability of nutrients is an essential factor controlling primary productivity in the ocean. In addition to macronutrients such as nitrogen and phosphorous, availability of the trace element iron unequivocally affects growth rates and community structure of phytoplankton and thereby primary productivity in many ocean regions. External sources of iron such as Aeolian dust, upwelling of Fe-rich waters, and hydrothermal are reduced in high-nutrient low-chlorophyll regions, and most Fe used by phytoplankton has been regenerated by zooplankton. While zooplankton regeneration of Fe was first shown two decades ago, major factors controlling this process such as chemical composition of prey and grazer taxonomy are not well constrained. As pH varies significantly in digestive systems between protozoa and mesozooplankton, we hypothesize that the extent and the bioavailability of regenerated Fe is a function of the digestive physiology. Furthermore, major element components such as silica for diatoms and calcium carbonate for cocolithophores may be able to buffer the pH of digestive systems of different grazer taxa. Such effects may further influence the magnitude and bioavailability of regenerated Fe. In order to constrain the effect of grazer taxonomy and chemical composition of prey on Fe bioavailability, 55Fe-labeled phytoplankton were fed to different grazers and unlabeled phytoplankton were subsequently inoculated to the filtrate of the grazing experiment in the regrowth phase of the experiment, and the uptake of 55Fe into the phytoplankton biomass was monitored over time. A parallel uptake experiment using inorganic 55Fe was used to compare the bioavailability of regenerated and inorganic Fe to the same phytoplankton species. Furthermore, some samples of the inorganic and the regenerated uptake experiments were treated with an oxalate rinse to remove any adsorbed Fe. This allowed us to estimate the adsorption of 55Fe from either source to the cell walls of

  16. Simulation of magnetic active polymers for versatile microfluidic devices

    Binder Claudia; Kataeva Nadezhda; Bance Simon; Exl Lukas; Reichel Franz; Fischbacher Johann; Özelt Harald; Gusenbauer Markus; Brückl Hubert; Schrefl Thomas

    2013-01-01

    We propose to use a compound of magnetic nanoparticles (20-100 nm) embedded in a flexible polymer (Polydimethylsiloxane PDMS) to filter circulating tumor cells (CTCs). The analysis of CTCs is an emerging tool for cancer biology research and clinical cancer management including the detection, diagnosis and monitoring of cancer. The combination of experiments and simulations lead to a versatile microfluidic lab-on-chip device. Simulations are essential to understand the influence of the embedde...

  17. Highly active antibody-modified magnetic polyelectrolyte capsules.

    Valdepérez, Daniel; Del Pino, Pablo; Sánchez, Lourdes; Parak, Wolfgang J; Pelaz, Beatriz

    2016-07-15

    Polyelectrolyte hollow capsules are versatile platforms typically used for encapsulation of a wide variety of macromolecules in their cavity. The polymer shell of these capsules as composed by alternating layers of oppositely charged polyelectrolytes also allows for adding additional functionalities. The properties of the shell can be for example engineered by trapping different nanoparticles in-between the shell layers and/or by attaching bioactive molecules such as antibodies to the outermost layer. Herein, iron oxide NPs were inmobilized into the shell of polyelectrolyte capsules and the outermost layer of the shell was covalently modified with anti peroxidase antibodies. These capsules act as prototype model system, aiming to obtain a microstructure with the potential capability to specifically recognize and separate macromolecules. Due to the magnetic nanoparticles in the capsule shell, the capsules together with the attached target might be extracted by magnetic field gradients. Here we verified this approach by extracting horseradish peroxidase from a solution through magnetic separation with capsules bearing antibodies against horseradish peroxidase. The bioactivity of the capsules and the high degree of specific antibody functionalization were confirmed and quantified through an enzymatic reaction mediated by the extracted horseradish peroxidase. PMID:27089014

  18. MAGNET

    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 ...

  19. Effect of Static Magnetic Field on α-Amylase Activity and Enzymatic Reaction

    JIA Shaoyi; LIU Yong; WU Songhai; WANG Zhibin

    2009-01-01

    The effect of magnetic field on α-amylase was studied. Under the experimental conditions, α-amylase solution was treated by 0.15 T, 0.30 T and 0.45 T static magnetic fields for a known period of time, then the activ-ity, kinetic parameters, and the secondary conformation were investigated. The results showed that there was a con-siderable effect of the magnetic exposure on the α-amylase. The activity was increased by 27%, 34.1%, 37.8% compared with the control. It was also found that both kinetic parameters Km and Vm could be decreased due to the increasing magnetic field, Km decreased from 2.20×102 to 0.87×102, whereas Vm decreased from 2.0×103 g/min to 1.1×103g/min. At the same time, there were some irregular changes in α-amylase secondary conformation.

  20. Functional magnetic resonance imaging evaluation of visual cortex activation in patients with anterior visual pathway lesions

    Xiufeng Song; Guohua Wang; Tong Zhang; Lei Feng; Peng An; Yueli Zhu

    2012-01-01

    The aim of this study was to examine the secondary visual cortex functional disorder in patients with glaucoma and large pituitary adenoma by functional magnetic resonance imaging, and to determine the correlation between visual field defect and primary visual cortex activation. Results showed that single eye stimulation resulted in bilateral visual cortex activation in patients with glaucoma or large pituitary adenoma. Compared with the normal control group, the extent and intensity of visual cortex activation was decreased after left and right eye stimulation, and functional magnetic resonance imaging revealed a correlation between visual field defects and visual cortex activation in patients with glaucoma and large pituitary adenoma. These functional magnetic resonance imaging data suggest that anterior optic pathway lesions can cause secondary functional disorder of the visual cortex, and that visual defects are correlated with visual cortex activation.

  1. Radio wavelength observations of magnetic fields on active dwarf M, RS CVn and magnetic stars

    Lang, Kenneth R.

    1986-01-01

    The dwarf M stars, YZ Canis Minoris and AD Leonis, exhibit narrow-band, slowly varying (hours) microwave emission that cannot be explained by conventional thermal radiation mechanisms. The dwarf M stars, AD Leonis and Wolf 424, emit rapid spikes whose high brightness temperatures similarly require a nonthermal radiation process. They are attributed to coherent mechanisms such as an electron-cyclotron maser or coherent plasma radiation. If the electron-cyclotron maser emits at the second or third harmonic gyrofrequency, the coronal magnetic field strength equals 250 G or 167 G, and constraints on the plasma frequency imply an electron density of 6 x 10 to the 9th/cu cm. Radio spikes from AD Leonis and Wolf 424 have rise times less than or equal to 5 ms, indicating a linear size of less than or equal to 1.5 x 10 to the 8th cm, or less than 0.005 of the stellar radius. Although Ap magnetic stars have strong dipole magnetic fields, they exhibit no detectable gyroresonant radiation, suggesting that these stars do not have hot, dense coronae. The binary RS CVn star UX Arietis exhibits variable emission at 6 cm wavelength on time scales ranging from 30 s to more than one hour.

  2. Biomaterials for cardiac regeneration

    Ruel, Marc

    2015-01-01

    This book offers readers a comprehensive biomaterials-based approach to achieving clinically successful, functionally integrated vasculogenesis and myogenesis in the heart. Coverage is multidisciplinary, including the role of extracellular matrices in cardiac development, whole-heart tissue engineering, imaging the mechanisms and effects of biomaterial-based cardiac regeneration, and autologous bioengineered heart valves. Bringing current knowledge together into a single volume, this book provides a compendium to students and new researchers in the field and constitutes a platform to allow for future developments and collaborative approaches in biomaterials-based regenerative medicine, even beyond cardiac applications. This book also: Provides a valuable overview of the engineering of biomaterials for cardiac regeneration, including coverage of combined biomaterials and stem cells, as well as extracellular matrices Presents readers with multidisciplinary coverage of biomaterials for cardiac repair, including ...

  3. Bionanomaterials for skin regeneration

    Leonida, Mihaela D

    2016-01-01

    This book gives a concise overview of bionanomaterials with applications for skin regeneration. The advantages and challenges of nanoscale materials are covered in detail, giving a basic view of the skin structure and conditions that require transdermal or topical applications. Medical applications, such as wound healing, care for burns, skin disease, and cosmetic care, such as aging of the skin and photodamage, and how they benefit from bionanomaterials, are described in detail. A final chapter is devoted to the ethical and social issues related to the use of bionanomaterials for skin regeneration. This is an ideal book for researchers in materials science, medical scientists specialized in dermatology, and cosmetic chemists working in formulations. It can also serve as a reference for nanotechnologists, dermatologists, microbiologists, engineers, and polymer chemists, as well as students studying in these fields.

  4. Delayed liver regeneration after partial hepatectomy in adiponectin knockout mice

    We previously demonstrated that adiponectin has anti-fibrogenic and anti-inflammatory effects in the liver of mouse models of various liver diseases. However, its role in liver regeneration remains unclear. The aim of this study was to determine the role of adiponectin in liver regeneration. We assessed liver regeneration after partial hepatectomy in wild-type (WT) and adiponectin knockout (KO) mice. We analyzed DNA replication and various signaling pathways involved in cell proliferation and metabolism. Adiponectin KO mice exhibited delayed DNA replication and increased lipid accumulation in the regenerating liver. The expression levels of peroxisome proliferator-activated receptor (PPAR) α and carnitine palmitoyltransferase-1 (CPT-1), a key enzyme in mitochondrial fatty acid oxidation, were decreased in adiponectin KO mice, suggesting possible contribution of altered fat metabolism to these phenomena. Collectively, the present results highlight a new role for adiponectin in the process of liver regeneration.

  5. Activation of Reg gene, a gene for insulin-producing β-cell regeneration: Poly(ADP-ribose) polymerase binds Reg promoter and regulates the transcription by autopoly(ADP-ribosyl)ation

    Akiyama, Takako; Takasawa, Shin; Nata, Koji; Kobayashi, Seiichi; Abe, Michiaki; Shervani, Nausheen J.; Ikeda, Takayuki; NAKAGAWA, Kei; Unno, Michiaki; Matsuno, Seiki; Okamoto, Hiroshi

    2000-01-01

    The regeneration of pancreatic islet β cells is important for the prevention and cure of diabetes mellitus. We have demonstrated that the administration of poly(ADP-ribose) synthetase/polymerase (PARP) inhibitors such as nicotinamide to 90% depancreatized rats induces islet regeneration. From the regenerating islet-derived cDNA library, we have isolated Reg (regenerating gene) and demonstrated that Reg protein induces β-cell replication via the Reg receptor and ame...

  6. Activity of an enzyme immobilized on superparamagnetic particles in a rotational magnetic field

    Mizuki, Toru; Watanabe, Noriyuki; Nagaoka, Yutaka [Bio-Nano Electronics Research Centre, Toyo University, Saitama 350-8585 (Japan); Fukushima, Tadamasa [Shimadzu GLC Ltd., Phenomenex Support Centre, Tokyo 110-0016 (Japan); Morimoto, Hisao; Usami, Ron [Bio-Nano Electronics Research Centre, Toyo University, Saitama 350-8585 (Japan); Maekawa, Toru, E-mail: maekawa@toyonet.toyo.ac.jp [Bio-Nano Electronics Research Centre, Toyo University, Saitama 350-8585 (Japan)

    2010-03-19

    We immobilize {alpha}-amylase extracted from Bacillus Iicheniformis on the surfaces of superparamagnetic particles and investigate the effect of a rotational magnetic field on the enzyme's activity. We find that the activity of the enzyme molecules immobilized on superparamagnetic particles increases in the rotational magnetic field and reaches maximum at a certain frequency. We clarify the effect of the cluster structures formed by the superparamagnetic particles on the activity. Enzyme reactions are enhanced even in a tiny volume of solution using the present method, which is very important for the development of efficient micro reactors and micro total analysis systems ({mu}-TAS).

  7. Control of Surge in Centrifugal Compressors by Active Magnetic Bearings Theory and Implementation

    Yoon, Se Young; Allaire, Paul E

    2013-01-01

    Control of Surge in Centrifugal Compressors by Active Magnetic Bearings sets out the fundamentals of integrating the active magnetic bearing (AMB) rotor suspension technology in compressor systems, and describes how this relatively new bearing technology can be employed in the active control of compressor surge. The authors provide a self-contained and comprehensive review of rotordynamics and the fundamentals of the AMB technology. The active stabilization of compressor surge employing AMBs in a machine is fully explored, from the modeling of the instability and the design of feedback controllers, to the implementation and experimental testing of the control algorithms in a specially-constructed, industrial-size centrifugal compression system. The results of these tests demonstrate the great potential of the new surge control method developed in this text. This book will be useful for engineers in industries that involve turbocompressors and magnetic bearings, as well as for researchers and graduate students...

  8. Bone regeneration in dentistry

    Tonelli, Paolo; Duvina, Marco; Barbato, Luigi; Biondi, Eleonora; Nuti, Niccolò; Brancato, Leila; Rose, Giovanna Delle

    2011-01-01

    The edentulism of the jaws and the periodontal disease represent conditions that frequently leads to disruption of the alveolar bone. The loss of the tooth and of its bone of support lead to the creation of crestal defects or situation of maxillary atrophy. The restoration of a functional condition involves the use of endosseous implants who require adequate bone volume, to deal with the masticatory load. In such situations the bone need to be regenerated, taking advantage of the biological p...

  9. Determinants of axonal regeneration

    Frisén, J

    1997-01-01

    Axons often regrow to their targets and lost functions may be restored after an injury in the peripheral nervous system. In contrast, axonal regeneration is generally very limited after injuries in the central nervous system, and functional impairment is usually permanent. The regenerative capacity depends on intrinsic neuronal factors as weil as the interaction of neurons with other cells. Glial cells may, in different situations, either support or inhibit axo...

  10. Processing and characterization of activated carbon coated magnetic particles for biomedical applications

    Ramanujan, R.V. [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore)]. E-mail: ramanujan@ntu.edu.sg; Purushotham, S. [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Chia, M.H. [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2007-05-16

    Synthesis and characterization of Magnetically Targeted Carrier (MTC) powders consisting of activated carbon coated iron particles were carried out. Powders with activated carbon content of 5% by weight (Fe5C) and 35% by weight (Fe35C) were studied. Powders were synthesized via the high energy ball milling route, and the influence of milling time on the morphology, magnetic properties and drug adsorption and desorption characteristics was investigated. Physical and structural characterization included electron microscopy, size analysis, and X-ray diffraction. The magnetic properties, and theophylline adsorption and desorption characteristics were studied. Fe35C milled for 10 h was found to be a suitable candidate for MTC applications with fine size, stable magnetic properties, and superior drug adsorption and desorption behavior.

  11. Long-term variation in the Sun's activity caused by magnetic Rossby waves in the tachocline

    Zaqarashvili, T. V.; Oliver, R.; Hanslmeier, A.; Carbonell, M.; Ballester, J. L.; Gachechiladze, T.; I. G. Usoskin

    2015-01-01

    Long-term records of sunspot number and concentrations of cosmogenic radionuclides (10Be and 14C) on the Earth reveal the variation of the Sun's magnetic activity over hundreds and thousands of years. We identify several clear periods in sunspot, 10Be, and 14C data as 1000, 500, 350, 200 and 100 years. We found that the periods of the first five spherical harmonics of the slow magnetic Rossby mode in the presence of a steady toroidal magnetic field of 1200-1300 G in the lower tachocline are i...

  12. Temperature dependence of the activation energy at low magnetic induction in high-Tc superconductors

    The activation energy U0 has been measured for melt-textured YBa2Cu3O7 samples at low magnetic induction B parallel c. The data indicate that U0 has a nearly linear temperature dependence in a certain temperature regime (congruent 10--60 K) and is insensitive to magnetic induction. In terms of the collective-pinning ideas and taking into account the modification due to the thermal fluctuation of the flux-line lattice, we propose a possible theoretical explanation. Meanwhile, the critical current Jc, which depends upon the magnetic induction B as Jc∝1/ √B , was obtained

  13. Magnetic Fusion Energy Technology Fellowship Program: Summary of program activities for calendar year 1985

    This report summarizes the activities of the US Department of Energy (DOE) Magnetic Fusion Energy Technology Fellowship program (MFETF) for the 1985 calendar year. The MFETF program has continued to support the mission of the Office of Fusion Energy (OFE) and its Division of Development and Technology (DDT) by ensuring the availability of appropriately trained engineering manpower needed to implement the OFE/DDT magnetic fusion energy agenda. This program provides training and research opportunities to highly qualified students at DOE-designated academic, private sector, and government magnetic fusion energy institutions. The objectives of the Magnetic Fusion Energy Technology Fellowship program are: (1) to provide support for graduate study, training, and research in magnetic fusion energy technology; (2) to ensure an adequate supply of appropriately trained manpower to implement the nation's magnetic fusion energy agenda; (3) to raise the visibility of careers in magnetic fusion energy technology and to encourage students to pursue such careers; and (4) to make national magnetic fusion energy facilities available for manpower training

  14. A Comprehensive Transcriptomic and Proteomic Analysis of Hydra Head Regeneration.

    Petersen, Hendrik O; Höger, Stefanie K; Looso, Mario; Lengfeld, Tobias; Kuhn, Anne; Warnken, Uwe; Nishimiya-Fujisawa, Chiemi; Schnölzer, Martina; Krüger, Marcus; Özbek, Suat; Simakov, Oleg; Holstein, Thomas W

    2015-08-01

    The cnidarian freshwater polyp Hydra sp. exhibits an unparalleled regeneration capacity in the animal kingdom. Using an integrative transcriptomic and stable isotope labeling by amino acids in cell culture proteomic/phosphoproteomic approach, we studied stem cell-based regeneration in Hydra polyps. As major contributors to head regeneration, we identified diverse signaling pathways adopted for the regeneration response as well as enriched novel genes. Our global analysis reveals two distinct molecular cascades: an early injury response and a subsequent, signaling driven patterning of the regenerating tissue. A key factor of the initial injury response is a general stabilization of proteins and a net upregulation of transcripts, which is followed by a subsequent activation cascade of signaling molecules including Wnts and transforming growth factor (TGF) beta-related factors. We observed moderate overlap between the factors contributing to proteomic and transcriptomic responses suggesting a decoupled regulation between the transcriptional and translational levels. Our data also indicate that interstitial stem cells and their derivatives (e.g., neurons) have no major role in Hydra head regeneration. Remarkably, we found an enrichment of evolutionarily more recent genes in the early regeneration response, whereas conserved genes are more enriched in the late phase. In addition, genes specific to the early injury response were enriched in transposon insertions. Genetic dynamicity and taxon-specific factors might therefore play a hitherto underestimated role in Hydra regeneration. PMID:25841488

  15. THE EXPERIMENTAL TESTING OF AN ACTIVE MAGNETIC BEARING/ROTOR SYSTEM UNDERGOING BASE EXCITATION

    Clements, Joshua Ryan

    2000-01-01

    Active Magnetic Bearings (AMB) are a relatively recent innovation in bearing technology. Unlike conventional bearings, which rely on mechanical forces originating from fluid films or physical contact to support bearing loads, AMB systems utilize magnetic fields to levitate and support a shaft in an air-gap within the bearing stator. This design has many benefits over conventional bearings. The potential capabilities that AMB systems offer are allowing this new technology to be considered f...

  16. Engineering of Iron-Based Magnetic Activated Carbon Fabrics for Environmental Remediation

    Hai Haham; Judith Grinblat; Moulay-Tahar Sougrati; Lorenzo Stievano; Shlomo Margel

    2015-01-01

    Magnetic Fe3O4, Fe and Fe/Pd nanoparticles embedded within the pores of activated carbon fabrics (ACF) were prepared by impregnation of the ACF in iron acetylacetanoate (Fe(acac)3) ethanol solution, followed by thermal decomposition of the embedded iron precursor at 200, 400 and 600 °C in an inert atmosphere. The effect of the annealing temperature on the chemical composition, shape, crystallinity, surface area, pore volume, and magnetic properties of the various functionalized ACF was elucid...

  17. Magnetic activation of bipolar plasmas in HgTe-CdTe superlattices

    Meyer, J. R.; Hoffman, C. A.; Bartoli, F. J.; Wojtowicz, T.; Dobrowolska, M.; Furdyna, J. K.; Chu, X.; Faurie, J. P.; Ram-Mohan, L. R.

    1991-08-01

    It is shown theoretically that in semimetallic HgTe-CdTe superlattices, there is a critical magnetic field above which minority carriers with density proportional to B-Bcrit are expected to coexist with majority carriers in the zero-temperature limit. Experimental confirmation of the magnetically activated bipolar plasma is provided by low-temperature magneto-optical data showing the emergence of minority holes in an n-type superlattice whenever B>Bcrit.

  18. Strong geomagnetic activity forecast by neural networks under dominant southern orientation of the interplanetary magnetic field

    Valach, F.; Bochníček, Josef; Hejda, Pavel; Revallo, M.

    2014-01-01

    Roč. 53, č. 4 (2014), s. 589-598. ISSN 0273-1177 R&D Projects: GA AV ČR(CZ) IAA300120608; GA MŠk OC09070 Institutional support: RVO:67985530 Keywords : geomagnetic activity * interplanetary magnetic field * artificial neural network * ejection of coronal mass * X-ray flares Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 1.358, year: 2014

  19. On Asymmetry of Magnetic Helicity in Emerging Active Regions: High Resolution Observations

    Tian, Lirong; Démoulin, Pascal; Alexander, David; Zhu, Chunming

    2011-01-01

    We employ the DAVE (differential affine velocity estimator, Schuck 2005; 2006) tracking technique on a time series of MDI/1m high spatial resolution line- of-sight magnetograms to measure the photospheric flow velocity for three newly emerging bipolar active regions. We separately calculate the magnetic helicity injection rate of the leading and following polarities to confirm or refute the magnetic helicity asymmetry, found by Tian & Alexander (2009) using MDI/96m low spatial resolution magn...

  20. Coupling of the solar wind to measures of magnetic activity

    The technique of linear prediction filtering has been used to generate empirical response functions relating the solar wind electric field to the most frequently used magnetic indices, AL, AU, Dst and ASYM. Two datasets, one from 1967-1968 and one from 1973-1974, provided the information needed to calculate the empirical response functions. These functions have been convolved with solar wind observations obtained during the IMS to predict the indices. These predictions are compared with the observed indices during two, three-day intervals studied extensively by participants in the CDAW-6 workshop. Differences between the observed and predicted indices are discussed in terms of the linear assumption and in terms of physical processes other than direct solar wind-magnetosphere interaction

  1. Antibacterial activity of magnetic iron oxide nanoparticles synthesized by laser ablation in liquid

    Ismail, Raid A., E-mail: raidismail@yahoo.com [Laser Physics Division, Applied Science Department, University of Technology, Baghdad (Iraq); Sulaiman, Ghassan M. [Biotechnology Division, Applied Science Department, University of Technology, Baghdad (Iraq); Abdulrahman, Safa A. [Laser Physics Division, Applied Science Department, University of Technology, Baghdad (Iraq); Marzoog, Thorria R. [Biotechnology Division, Applied Science Department, University of Technology, Baghdad (Iraq)

    2015-08-01

    In this study, (50–110 nm) magnetic iron oxide (α-Fe{sub 2}O{sub 3}) nanoparticles were synthesized by pulsed laser ablation of iron target in dimethylformamide (DMF) and sodium dodecyl sulfate (SDS) solutions. The structural properties of the synthesized nanoparticles were investigated by using Fourier Transform Infrared (FT-IR) spectroscopy, UV–VIS absorption, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). The effect of laser fluence on the characteristics of these nanoparticles was studied. Antibacterial activities of iron oxide nanoparticles were tested against Gram-positive; Staphylococcus aureus and Gram-negative; Escherichia coli, Pseudomonas aeruginosa and Serratia marcescens. The results showed a noteworthy inhibition on both bacterial strains. The preparation conditions were found to affect significantly the antibacterial activity of these nanoparticles. The synthesized magnetic nanoparticles were used to capture rapidly S. aureus bacteria under the magnetic field effect. - Highlights: • Synthesis magnetic iron oxide nanoparticles by pulsed laser ablation • Antibacterial activity against Gram-positive and Gram-negative bacteria • Captured magnetic nanoparticles by S. aureus bacteria under effect of magnetic field.

  2. Magnetic Flux Transport and the Long-term Evolution of Solar Active Regions

    Ugarte-Urra, Ignacio; Upton, Lisa; Warren, Harry P.; Hathaway, David H.

    2015-12-01

    With multiple vantage points around the Sun, Solar Terrestrial Relations Observatory (STEREO) and Solar Dynamics Observatory imaging observations provide a unique opportunity to view the solar surface continuously. We use He ii 304 Å data from these observatories to isolate and track ten active regions and study their long-term evolution. We find that active regions typically follow a standard pattern of emergence over several days followed by a slower decay that is proportional in time to the peak intensity in the region. Since STEREO does not make direct observations of the magnetic field, we employ a flux-luminosity relationship to infer the total unsigned magnetic flux evolution. To investigate this magnetic flux decay over several rotations we use a surface flux transport model, the Advective Flux Transport model, that simulates convective flows using a time-varying velocity field and find that the model provides realistic predictions when information about the active region's magnetic field strength and distribution at peak flux is available. Finally, we illustrate how 304 Å images can be used as a proxy for magnetic flux measurements when magnetic field data is not accessible.

  3. Regenerable Fe-Mn-ZnO/SiO2 sorbents for room temperature removal of H2S from fuel reformates: performance, active sites, Operando studies.

    Dhage, Priyanka; Samokhvalov, Alexander; Repala, Divya; Duin, Evert C; Tatarchuk, Bruce J

    2011-02-14

    Fe- and Mn-promoted H(2)S sorbents Fe(x)-Mn(y)-Zn(1-x-y)O/SiO(2) (x, y = 0, 0.025) for desulfurization of model fuel reformates at room temperature were prepared, tested and characterized. Sulfur uptake capacity at 25 °C significantly exceeds that of both commercial unsupported ZnO sorbents and un-promoted supported ZnO/SiO(2) sorbents. Sulfur capacity and breakthrough characteristics remain satisfactory after multiple (∼10) cycles of adsorption/regeneration, with regeneration performed by a simple and robust heating in air. XRD shows that both "calcined" and "spent" sorbents contain nano-dispersed ZnO, and XPS confirms conversion of ZnO to ZnS. "Calcined" sorbent contains Fe(3+) and Mn(3+) that are reduced to Mn(2+) upon reaction with H(2)S, but not with H(2). Operando ESR is used for the first time to study dynamics of reduction of Mn(3+) promoter sites simultaneously with measuring sulfidation dynamics of the Fe(x)-Mn(y)-Zn(1-x-y)O/SiO(2) sorbent. Fe cations are believed to occupy the surface of supported ZnO nanocrystallites, while Mn cations are distributed within ZnO. PMID:21132188

  4. Using Magnetic Helicity Diagnostics to Determine the Nature of Solar Active-Region Formation

    Georgoulis, Manolis K.

    Employing a novel nonlinear force-free (NLFF) method that self-consistently infers instantaneous free magnetic-energy and relative magnetic-helicity budgets from single photospheric vector magnetograms, we recently constructed the magnetic energy-helicity (EH) diagram of solar active regions. The EH diagram implies dominant relative helicities of left-handed or right-handed chiralities for the great majority of active regions. The amplitude (budget) of these helicities scales monotonically with the free magnetic energy. This constructive, strongly preferential accumulation of a certain sense of magnetic helicity seems to disqualify recently proposed mechanisms relying on a largely random near-surface convection for the formation of the great majority of active regions. The existing qualitative formation mechanism for these regions remains the conventional Omega-loop emergence following a buoyant ascension from the bottom of the convection zone. However, exceptions to this rule include even eruptive active regions: NOAA AR 11283 is an obvious outlier to the EH diagram, involving significant free magnetic energy with a small relative magnetic helicity. Relying on a timeseries of vector magnetograms of this region, our methodology shows nearly canceling amounts of both senses of helicity and an overall course from a weakly left-handed to a weakly right-handed structure, in the course of which a major eruption occurs. For this and similarly behaving active regions the latest near-surface formation scenario might conceivably be employed successfully. Research partially supported by the EU Seventh Framework Programme under grant agreement No. PIRG07-GA-2010-268245 and by the European Union Social Fund (ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) - Research Funding Program: Thales. Investing in knowledge society through the European Social Fund.

  5. EVOLUTION OF RELATIVE MAGNETIC HELICITY AND CURRENT HELICITY IN NOAA ACTIVE REGION 11158

    Both magnetic and current helicities are crucial ingredients for describing the complexity of active-region magnetic structure. In this Letter, we present the temporal evolution of these helicities contained in NOAA active region 11158 during five days from 2011 February 12 to 16. The photospheric vector magnetograms of the Helioseismic and Magnetic Imager on board the Solar Dynamic Observatory were used as the boundary conditions for the coronal field extrapolation under the assumption of nonlinear force-free field, from which we calculated both relative magnetic helicity and current helicity. We construct a time-altitude diagram in which altitude distribution of the magnitude of current helicity density is displayed as a function of time. This diagram clearly shows a pattern of upwardly propagating current helicity density over two days prior to the X2.2 flare on February 15 with an average propagation speed of ∼36 m s–1. The propagation is synchronous with the emergence of magnetic flux into the photosphere, and indicative of a gradual energy buildup for the X2.2 flare. The time profile of the relative magnetic helicity shows a monotonically increasing trend most of the time, but a pattern of increasing and decreasing magnetic helicity above the monotonic variation appears prior to each of two major flares, M6.6 and X2.2, respectively. The physics underlying this bump pattern is not fully understood. However, the fact that this pattern is apparent in the magnetic helicity evolution but not in the magnetic flux evolution makes it a useful indicator in forecasting major flares.

  6. Magnetic properties and adsorptive performance of manganese–zinc ferrites/activated carbon nanocomposites

    Owing to the unique microstructure and high specific surface area, activated carbon (AC) could act as an excellent adsorbent for wastewater treatment and good carrier for functional materials. In this paper, manganese–zinc ferrites (Mn0.5Zn0.5Fe2O4: MZF) were anchored into AC by hydrothermal method, resulting in the excellent magnetic response for AC nanocomposites in wastewater treatment. All results demonstrated the magnetic nanoparticles presented a spinel phase structure and existed in the pores of AC. The saturation magnetization (Ms) of MZF/AC nanocomposites increased with the ferrites content, while the pore volume and specific surface area declined. The Sample-5 possessed the specific surface area of 1129 m2 g−1 (close to 1243 m2 g−1 of AC) and Ms of 3.96 emu g−1. Furthermore, the adsorptive performance for organic dyes was studied and 99% methylene blue was adsorbed in 30 min. The magnetic AC nanocomposites could be separated easily from solution by magnetic separation technique. - Graphical abstract: The Sample-5 presented both good magnetic response and high BET surface area up to 1129 m2 g−1 (close to AC of 1243 m2 g−1), which could be separated completely for about 60 s. MZF/AC nanocomposites (Sample-3, 4, 5) in our work could be used as the magnetic absorbents, which could be separated easily by an outer magnet after the MB adsorption. - Highlights: • Mn0.5Zn0.5Fe2O4 (MZF) as few as possible was implanted into activated carbon (AC) for the higher surface area. • Sample-5 possessed the high specific surface area (1129 m2 g−1) and the suitable Ms (3.96 emu g−1). • Methylene blue was adsorbed almost completely by MZF/AC nanocomposites in 30 min. • MZF/AC nanocomposites were separated easily from solution by magnetic separation technique

  7. Magnetic Nonpotentiality in Photospheric Active Regions as a Predictor of Solar Flares

    Yang, Xiao; Zhang, HongQi; Mao, XinJie

    2013-01-01

    Based on several magnetic nonpotentiality parameters obtained from the vector photospheric active region magnetograms obtained with the Solar Magnetic Field Telescope at the Huairou Solar Observing Station over two solar cycles, a machine learning model has been constructed to predict the occurrence of flares in the corresponding active region within a certain time window. The Support Vector Classifier, a widely used general classifier, is applied to build and test the prediction models. Several classical verification measures are adopted to assess the quality of the predictions. We investigate different flare levels within various time windows, and thus it is possible to estimate the rough classes and erupting times of flares for particular active regions. Several combinations of predictors have been tested in the experiments. The True Skill Statistics are higher than 0.36 in 97% of cases and the Heidke Skill Scores range from 0.23 to 0.48. The predictors derived from longitudinal magnetic fields do perform ...

  8. Stellar magnetic activity and their influence on the habitability of exoplanets

    Lüftinger, T; Johnstone, C P

    2015-01-01

    Stellar magnetism, explorable via polarimetry, is a crucial driver of activity, ionization, photodissociation, chemistry and winds in stellar environments. Thus it has an important impact on the atmospheres and magnetospheres of surrounding planets. Modeling of stellar magnetic fields and their winds is extremely challenging, both from the observational and the theoretical points of view, and only recent ground breaking advances in observational instrumentation - as were discussed during this Symposium - and a deeper theoretical understanding of magnetohydrodynamic processes in stars enable us to model stellar magnetic fields and winds and the resulting influence on surrounding planets in more and more detail. We have initiated a national and international research network (NFN): 'Pathways to Habitability - From Disks to Active Stars, Planets to Life', to address questions on the formation and habitability of environments in young, active stellar/planetary systems. In this contribution we discuss the work we ...

  9. A Comparison Between Global Proxies of the Sun's Magnetic Activity Cycle: Inferences from Helioseismology

    Broomhall, A -M

    2015-01-01

    The last solar minimum was, by recent standards, unusually deep and long. We are now close to the maximum of the subsequent solar cycle, which is relatively weak. In this article we make comparisons between different global (unresolved) measures of the Sun's magnetic activity, to investigate how they are responding to this weak-activity epoch. We focus on helioseismic data, which are sensitive to conditions, including the characteristics of the magnetic field, in the solar interior. Also considered are measures of the magnetic field in the photosphere (sunspot number and sunspot area), the chromosphere and corona (10.7cm radio flux and 530.3nm green coronal index), and two measures of the Sun's magnetic activity closer to Earth (the interplanetary magnetic field and the galactic cosmic-ray intensity). Scaled versions of the activity proxies diverge from the helioseismic data around 2000, indicating a change in relationship between the proxies. The degree of divergence varies from proxy to proxy with sunspot a...

  10. Proton magnetic resonance spectroscopy reflects cellular proliferative activity in astrocytomas

    We examined whether proton magnetic resonance spectroscopy (MRS) could provide accurate information on histological grade and cell proliferation in astrocytomas. We studied 23 patients with astrocytomas: five grade II, 10 grade III and eight with grade IV (glioblastoma multiforme). We performed proton MRS and determined the Ki-67 labeling index (LI), a tumour proliferation marker, in the same areas of the astrocytomas, and examined the statistical relationship between proton MRS and Ki-67 LI. The N-acetylaspartate (NAA)/creatine-phosphocreatine (Cr) and NAA/choline (Cho)-containing compound ratios were always significantly lower and the Cho/Cr ratios significantly higher than those for normal brain. The Cho/Cr ratio correlated positively and the NAA/Cho ratio inversely with Ki-67 LI. These findings suggest that the Cho signal in proton MRS reflects cellular proliferation. In Kaplan-Meier survival analysis, there was no significant difference between high (> 2.0, 14 cases) and low (< 2.0, 9 cases) Cho/cr ratio groups. (orig.)

  11. Effect of the active damper coil system on the lateral displacement of the magnetically levitated bogie

    Ohashi, S.; Ohsaki, H.; Masada, E.

    1999-09-01

    Numerical simulation of the superconducting magnetically levitated bogie (JR Maglev) has been studied. The active damper coil system is introduced. In this levitation system, the interaction between levitation and guidance is strong. This active damper coil system is designed for reducing the vertical vibration of the bogie. Using the numerical simulation, its effect on the lateral displacement of the bogie is assessed. The active damper coil system for the vertical vibration is shown to works as a passive damper for the lateral vibration.

  12. Workshop Physics Activity Guide, Module 4: Electricity and Magnetism

    Laws, Priscilla W.

    2004-05-01

    The Workshop Physics Activity Guide is a set of student workbooks designed to serve as the foundation for a two-semester calculus-based introductory physics course. It consists of 28 units that interweave text materials with activities that include prediction, qualitative observation, explanation, equation derivation, mathematical modeling, quantitative experiments, and problem solving. Students use a powerful set of computer tools to record, display, and analyze data, as well as to develop mathematical models of physical phenomena. The design of many of the activities is based on the outcomes of physics education research. The Workshop Physics Activity Guide is supported by an Instructor's Website that: (1) describes the history and philosophy of the Workshop Physics Project; (2) provides advice on how to integrate the Guide into a variety of educational settings; (3) provides information on computer tools (hardware and software) and apparatus; and (4) includes suggested homework assignments for each unit. Log on to the Workshop Physics Project website at http://physics.dickinson.edu/ Workshop Physics is a component of the Physics Suite--a collection of materials created by a group of educational reformers known as the Activity Based Physics Group. The Physics Suite contains a broad array of curricular materials that are based on physics education research, including: Understanding Physics, by Cummings, Laws, Redish and Cooney (an introductory textbook based on the best-selling text by Halliday/Resnick/Walker) RealTime Physics Laboratory Modules Physics by Inquiry (intended for use in a workshop setting) Interactive Lecture Demonstration Tutorials in Introductory Physics Activity Based Tutorials (designed primarily for use in recitations)

  13. Neutral-Line Magnetic Shear and Enhanced Coronal Heating in Solar Active Regions

    Falconer, D. A.; Moore, R. L.; Porter, J. G.; Gary, G. A.; Shimizu, T.

    1997-01-01

    By examining the magnetic structure at sites in the bright coronal interiors of active regions that are not flaring but exhibit persistent strong coronal heating, we establish some new characteristics of the magnetic origins of this heating. We have examined the magnetic structure of these sites in five active regions, each of which was well observed by both the Yohkoh SXT and the Marshall Space Flight Center Vector Magnetograph and showed strong shear in its magnetic field along part of at least one neutral line (polarity inversion). Thus, we can assess whether this form of nonpotential field structure in active regions is a characteristic of the enhanced coronal heating and vice versa. From 27 orbits' worth of Yohkoh SXT images of the five active regions, we have obtained a sample of 94 persistently bright coronal features (bright in all images from a given orbit), 40 long (greater than or approximately equals 20,000 km) neutral-line segments having strong magnetic shear throughout (shear angle greater than 45 deg), and 39 long neutral-line segments having weak magnetic shear throughout (shear angle less than 45 deg). From this sample, we find that: (1) all of our persistently bright coronal features are rooted in magnetic fields that are stronger than 150 G; (2) nearly all (95%) of these enhanced coronal features are rooted near neutral lines (closer than 10,000 km); (3) a great majority (80%) of the bright features are rooted near strong-shear portions of neutral lines; (4) a great majority (85%) of long strong-shear segments of neutral lines have persistently bright coronal features rooted near them; (5) a large minority (40%) of long weak-shear segments of neutral lines have persistently bright coronal features rooted near them; and (6) the brightness of a persistently bright Coronal feature often changes greatly over a few hours. From these results, we conclude that most persistent enhanced heating of coronal loops in active regions: (1) requires the

  14. Approaches Towards Endogenous Pancreatic Regeneration

    Banerjee, Meenal; Kanitkar, Meghana; Bhonde, Ramesh R.

    2005-01-01

    The phenomenon of pancreatic regeneration in mammals has been well documented. It has been shown that pancreatic tissue is able to regenerate in several species of mammal after surgical insult. This tissue is also known to have the potential to maintain or increase its β-cell mass in response to metabolic demands during pregnancy and obesity. Since deficiency in β-cell mass is the hallmark of most forms of diabetes, it is worthwhile understanding pancreatic regeneration in the context of this...

  15. URBAN REGENERATION PROCESSES IN RIGA

    Guntis Šolks

    2013-01-01

    URBAN REGENERATION PROCESSES IN RIGA ANNOTATION Urban regeneration is characterized by various forms and implications and it is an important research issue for modern urban geography. Riga also has experienced various transformations since the reestablishment of the independence of Latvia. Urban regeneration have an important role in the urban transformation processes, what are providing the revitalization and reuse of urban brownfields, thus contributing to sustainable u...

  16. Stochastic non-circular motion and outflows driven by magnetic activity in the Galactic bulge region

    Suzuki, Takeru K.; Fukui, Yasuo; Torii, Kazufumi; Machida, Mami; Matsumoto, Ryoji

    2015-12-01

    By performing a global magnetohydrodynamical simulation for the Milky Way with an axisymmetric gravitational potential, we propose that spatially dependent amplification of magnetic fields possibly explains the observed noncircular motion of the gas in the Galactic centre region. The radial distribution of the rotation frequency in the bulge region is not monotonic in general. The amplification of the magnetic field is enhanced in regions with stronger differential rotation, because magnetorotational instability and field-line stretching are more effective. The strength of the amplified magnetic field reaches ≳0.5 mG, and radial flows of the gas are excited by the inhomogeneous transport of angular momentum through turbulent magnetic field that is amplified in a spatially dependent manner. In addition, the magnetic pressure-gradient force also drives radial flows in a similar manner. As a result, the simulated position-velocity diagram exhibits a time-dependent asymmetric parallelogram-shape owing to the intermittency of the magnetic turbulence; the present model provides a viable alternative to the bar-potential-driven model for the parallelogram shape of the central molecular zone. This is a natural extension into the central few 100 pc of the magnetic activity, which is observed as molecular loops at radii from a few 100 pc to 1 kpc. Furthermore, the time-averaged net gas flow is directed outward, whereas the flows are highly time dependent, which we discuss from a viewpoint of the outflow from the bulge.

  17. Performance of biological magnetic powdered activated carbon for drinking water purification.

    Lompe, Kim Maren; Menard, David; Barbeau, Benoit

    2016-06-01

    Combining the high adsorption capacity of powdered activated carbon (PAC) with magnetic properties of iron oxide nanoparticles (NPs) leads to a promising composite material, magnetic PAC or MPAC, which can be separated from water using magnetic separators. We propose MPAC as an alternative adsorbent in the biological hybrid membrane process and demonstrate that PAC covered with magnetic NPs is suitable as growth support for heterotrophic and nitrifying bacteria. MPAC with mass fractions of 0; 23; 38 and 54% maghemite was colonized in small bioreactors for over 90 days. Although the bacterial community composition (16s rRNA analysis) was different on MPAC compared to PAC, NPs neither inhibited dissolved organic carbon and ammonia biological removals nor contributed to significant adsorption of these compounds. The same amount of active heterotrophic biomass (48 μg C/cm(3)) developed on MPAC with a mass fraction of 54% NPs as on the non-magnetic PAC control. While X-ray diffraction confirmed that size and type of iron oxides did not change over the study period, a loss in magnetization between 10% and 34% was recorded. PMID:27017574

  18. The evolution of magnetic activity on V711 Tauri and evidence for a significant facular contribution

    Dorren, J. D.; Guinan, E. F.

    1990-01-01

    The nature of the long-term evolution of magnetic activity in the RS CVn binary V711 Tauri is investigated using the complete set of available archival IUE SWP low-dispersion spectra of V711 Tau for the period covering August 1978 - December 1984. An analysis of the spectra confirmed the pattern of a long-term smooth variation of chromospheric and transition region emission found previosly by Dorren et al. (1986). An explanation of the relationship between the different facets of the magnetic activity on V711 Tau is presented.

  19. Tissue Regeneration in Urodela on Foton-M3

    Grigoryan, E. N.; Poplinskaya, V. A.; Domaratskaya, E. I.; Novikova, Y. P.; Aleinikova, K. S.; Dvorochkin, N.; Almeida, E. A. C.

    2008-06-01

    In the experiment "Regeneration" flown on Foton-M3 in 2007 we continued our study of tissue and organ regeneration in Urodela. Special attention was given to the regulatory mechanisms that could induce peculiarities of regeneration during the spaceflight. The results obtained showed that lens regeneration in space-flown animals was synchronized and about 0.5 to 1 stage more advanced than in synchronous 1g controls. In both groups of animals cytokine FGFb expression increased in parallel with lens cell mitotic activity and was localized in the growth zone and iris of regenerating eyes. Lens regeneration was also accompanied by an increase of stress protein (HSP90) expression in retinal macroglia. Evaluation of HSP90 and FGFb expression by immuno-staining showed that it was higher in the eyes of space-flown animals than in synchronous controls. BrdU assay demonstrated incorporation of the precursor into populations of DNA synthesizing cells in both animal groups and mirrored cell growth in regenerating tissues. Tail regeneration in space-flown and synchronous control animals reached the stages IV to V. Computer morphometry showed that tail size parameters were similar though the tail area was slightly decreased in the space-flown newts. In contrast, remarkable changes in tail tip morphology were found between animal groups: flight and aquarium-control tail regenerates were identical in shape, while synchronous controls developed distinct dorsoventral asymmetry. Histological examinations suggested that morphogenetic differences were caused by different rates of epidermal cell growth in tail regenerates of newts exposed to microgravity and 1 g.

  20. MAGNET

    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...

  1. MAGNET

    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...

  2. MAGNET

    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...

  3. Hyperactivated Stat3 boosts axon regeneration in the CNS.

    Mehta, Saloni T; Luo, Xueting; Park, Kevin K; Bixby, John L; Lemmon, Vance P

    2016-06-01

    Axonal regeneration after spinal cord injury (SCI) is intrinsically and extrinsically inhibited by multiple factors. One major factor contributing to intrinsic regeneration failure is the inability of mature neurons in the central nervous system (CNS) to activate regeneration-associated transcription factors (TFs) post-injury. A prior study identified TFs overexpressed in neurons of the peripheral nervous system (PNS) compared to the CNS; some of these could be involved in the ability of PNS neurons to regenerate. Of these, signal transducer and activator of transcription 3 (STAT3), as well its downstream regeneration-associated targets, showed a significant upregulation in PNS neurons relative to CNS neurons, and a constitutively active variant of Stat3 (Stat3CA) promoted neurite growth when expressed in cerebellar neurons (Lerch et al., 2012; Smith et al., 2011). To further enhance STAT3's neurite outgrowth enhancing activity, Stat3CA was fused with a viral activation domain (VP16). VP16 hyperactivates TFs by recruiting transcriptional co-factors to the DNA binding domain (Hirai et al., 2010). Overexpression of this VP16-Stat3CA chimera in primary cortical neurons led to a significant increase of neurite outgrowth as well as Stat3 transcriptional activity in vitro. Furthermore, in vivo transduction of retinal ganglion cells (RGCs) with AAV constructs expressing VP16-Stat3CA resulted in regeneration of optic nerve axons after injury, to a greater degree than for those expressing Stat3CA alone. These findings confirm and extend the concept that overexpression of hyperactivated transcription factors identified as functioning in PNS regeneration can promote axon regeneration in the CNS. PMID:27060489

  4. Simulation of magnetic active polymers for versatile microfluidic devices

    Binder Claudia

    2013-01-01

    Full Text Available We propose to use a compound of magnetic nanoparticles (20–100 nm embedded in a flexible polymer (Polydimethylsiloxane PDMS to filter circulating tumor cells (CTCs. The analysis of CTCs is an emerging tool for cancer biology research and clinical cancer management including the detection, diagnosis and monitoring of cancer. The combination of experiments and simulations lead to a versatile microfluidic lab-on-chip device. Simulations are essential to understand the influence of the embedded nanoparticles in the elastic PDMS when applying a magnetic gradient field. It combines finite element calculations of the polymer, magnetic simulations of the embedded nanoparticles and the fluid dynamic calculations of blood plasma and blood cells. With the use of magnetic active polymers a wide range of tunable microfluidic structures can be created. The method can help to increase the yield of needed isolated CTCs.

  5. Rapid eye movement-related brain activation in human sleep: a functional magnetic resonance imaging study.

    Wehrle, Renate; Czisch, Michael; Kaufmann, Christian; Wetter, Thomas C; Holsboer, Florian; Auer, Dorothee P; Pollmächer, Thomas

    2005-05-31

    In animal models, ponto-geniculo-occipital waves appear as an early sign of rapid eye movement sleep and may be functionally significant for brain plasticity processes. In this pilot study, we use a combined polysomnographic and functional magnetic resonance imaging approach, and show distinct magnetic resonance imaging signal increases in the posterior thalamus and occipital cortex in close temporal relationship to rapid eye movements during human rapid eye movement sleep. These findings are consistent with cell recordings in animal experiments and demonstrate that functional magnetic resonance imaging can be utilized to detect ponto-geniculo-occipital-like activity in humans. Studying intact neuronal networks underlying sleep regulation is no longer confined to animal models, but has been shown to be feasible in humans by a combined functional magnetic resonance imaging and electroencephalograph approach. PMID:15891584

  6. Active region filaments might harbor weak magnetic fields

    Baso, C J Díaz; Ramos, A Asensio

    2016-01-01

    Recent spectropolarimetric observations of active region filaments have revealed polarization profiles with signatures typical of the strong field Zeeman regime. The conspicuous absence in those observations of scattering polarization and Hanle effect signatures was then pointed out by some authors. This was interpreted either as a signature of mixed "turbulent" field components or as a result of optical thickness. In this article, we present a natural scenario to explain these Zeeman-only spectro-polarimetric observations of active region filaments. We propose a two-component model, one on top of the other. Both components have horizontal fields, the azimuth difference between them being close to 90 degrees. The component that lies lower in the atmosphere is permeated by a strong field of the order of 600 G, while the upper component has much weaker fields, of the order of 10 G. The ensuing scattering polarization signatures of the individual components have opposite signs, so that its combination along the ...

  7. Photospheric activity, rotation and magnetic interaction in LHS 6343 A

    Herrero, E; Ribas, I; Jordi, C; Morales, J C

    2013-01-01

    Context. The Kepler mission has recently discovered a brown dwarf companion transiting one member of the M4V+M5V visual binary system LHS 6343 AB with an orbital period of 12.71 days. Aims. The particular interest of this transiting system lies in the synchronicity between the transits of the brown dwarf C component and the main modulation observed in the light curve, which is assumed to be caused by rotating starspots on the A component. We model the activity of this star by deriving maps of the active regions that allow us to study stellar rotation and the possible interaction with the brown dwarf companion. Methods. An average transit profile was derived, and the photometric perturbations due to spots occulted during transits are removed to derive more precise transit parameters. We applied a maximum entropy spot model to fit the out-of-transit optical modulation as observed by Kepler during an uninterrupted interval of 500 days. It assumes that stellar active regions consist of cool spots and bright facul...

  8. TWIST AND CONNECTIVITY OF MAGNETIC FIELD LINES IN THE SOLAR ACTIVE REGION NOAA 10930

    Twist and connectivity of magnetic field lines in the flare-productive active region NOAA 10930 are investigated in terms of the vector magnetograms observed by the Solar Optical Telescope on board the Hinode satellite and the nonlinear force-free field (NLFFF) extrapolation. First, we show that the footpoints of magnetic field lines reconstructed by the NLFFF correspond well to the conjugate pair of highly sheared flare ribbons on the Ca II images, which were observed by Hinode as an X3.4 class flare on 2006 December 13. This demonstrates that the NLFFF extrapolation may be used to analyze the magnetic field connectivity. Second, we find that the twist of magnetic field lines anchored on the flare ribbons increased as the ribbons moved away from the magnetic polarity inversion line in the early phase of the flare. This suggests that magnetic reconnection might commence from a region located below the most strongly twisted field. Third, we reveal that the magnetic flux twisted more than a half turn and gradually increased during the last one day prior to the onset of the flare, and that it quickly decreased for two hours after the flare. This is consistent with the store-and-release scenario of magnetic helicity. However, within this active region, only a small fraction of the flux was twisted by more than one full turn and the field lines that reconnected first were twisted less than one turn. These results imply that the kink mode instability could hardly occur, at least before the onset of flare. Based on our results, we discuss the trigger process of solar flares.

  9. Results of Russian geomagnetic observatories in the 19th century: magnetic activity, 1841–1862

    L. Häkkinen

    2010-04-01

    Full Text Available Hourly (spot readings magnetic data (H- and D-components were digitized from Russian yearbook tables for the years 1850–1862 from four observatories. The pdf pictures for digitization were taken by a normal digital camera. The database obtained consists of about 900 000 single data points. The time series of hourly magnetic values reveal slow secular variations (declination only as well as transient and regular geomagnetic variations of external origin. The quality and homogeneity of the data is satisfactory. Daily Ak-indices were calculated using the index algorithm that has been earlier applied to 19th century data from Helsinki (Finland as well as modern magnetic observatory recordings. The activity index series derived from the Russian data is consistent with earlier activity index series for 1850–1862. The digitized index data series derived in this study was extended back to 1841 by including magnetic C9 activity index data available from a Russian observatory (St. Petersburg. Magnetic data rescued here is well suitable for various reconstructions for studies of the long-term variation of the space weather in the 19th century.

  10. MAGNETIC ENERGY AND HELICITY IN TWO EMERGING ACTIVE REGIONS IN THE SUN

    Liu, Y. [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305-4085 (United States); Schuck, P. W. [Space Weather Laboratory, Code 674, Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2012-12-20

    The magnetic energy and relative magnetic helicity in two emerging solar active regions, AR 11072 and AR 11158, are studied. They are computed by integrating over time the energy and relative helicity fluxes across the photosphere. The fluxes consist of two components: one from photospheric tangential flows that shear and braid field lines (shear term), the other from normal flows that advect magnetic flux into the corona (emergence term). For these active regions: (1) relative magnetic helicity in the active-region corona is mainly contributed by the shear term, (2) helicity fluxes from the emergence and the shear terms have the same sign, (3) magnetic energy in the corona (including both potential energy and free energy) is mainly contributed by the emergence term, and (4) energy fluxes from the emergence term and the shear term evolved consistently in phase during the entire flux emergence course. We also examine the apparent tangential velocity derived by tracking field-line footpoints using a simple tracking method. It is found that this velocity is more consistent with tangential plasma velocity than with the flux transport velocity, which agrees with the conclusion by Schuck.

  11. Magnetic Energy and Helicity in Two Emerging Active Regions in the Sun

    Liu, Y.; Schuck, P. W.

    2012-01-01

    The magnetic energy and relative magnetic helicity in two emerging solar active regions, AR 11072 and AR 11158,are studied. They are computed by integrating over time the energy and relative helicity fluxes across the photosphere. The fluxes consist of two components: one from photospheric tangential flows that shear and braid field lines (shear term), the other from normal flows that advect magnetic flux into the corona (emergence term). For these active regions: (1) relative magnetic helicity in the active-region corona is mainly contributed by the shear term,(2) helicity fluxes from the emergence and the shear terms have the same sign, (3) magnetic energy in the corona (including both potential energy and free energy) is mainly contributed by the emergence term, and(4) energy fluxes from the emergence term and the shear term evolved consistently in phase during the entire flux emergence course.We also examine the apparent tangential velocity derived by tracking field-line footpoints using a simple tracking method. It is found that this velocity is more consistent with tangential plasma velocity than with the flux transport velocity, which agrees with the conclusion by Schuck.

  12. ADSORPTION PROPERTIES OF NICKEL-BASED MAGNETIC ACTIVATED CARBON PREPARED BY PD-FREE ELECTROLESS PLATING

    Boyang Jia

    2011-02-01

    Full Text Available Nickel-based magnetic activated carbon was synthesized from coconut shell activated carbon by electroless plating with palladium-free activation. The effect of plating solution volume on metallic ratio and adsorption capacity were evaluated. The effect of metallic ratio on specific area, pore volume, and magnetic properties were investigated. The morphologies of activated carbon before and after plating were observed by SEM, and the composition of the layer was analyzed by EDS analysis. The results showed that the metallic ratio was increased with the increase of the plating solution volume. The magnetic activated carbon showed high adsorption capacity for methylene blue and a high iodine number. Those values reached 142.5 mg/g and 1035 mg/g, respectively. The specific area and pore volume decreased from 943 m2/g to 859 m2/g and 0.462 ml/g to 0.417 ml/g, respectively. And the layer was more compact and continuous when the metallic ratio reached 16.37 wt.%. In the layer, there was about 97 wt.% nickel and 3 wt.% phosphorus, which indicates that the layer was a low-phosphorus one. At the same time, magnetism was enhanced, making the product suitable for some special applications.

  13. Visual activation in infants and young children studied by functional magnetic resonance imaging

    Born, Alfred Peter; Leth, H; Miranda Gimenez-Ricco, Maria Jo;

    1998-01-01

    The purpose of this study was to determine whether visual stimulation in sleeping infants and young children can be examined by functional magnetic resonance imaging. We studied 17 children, aged 3 d to 48 mo, and three healthy adults. Visual stimulation was performed with 8-Hz flickering light...... through the sleeping childs' closed eyelids. Functional magnetic resonance imaging was performed with a gradient echoplanar sequence in a l.5-T magnetic resonance scanner. Six subjects were excluded because of movement artifacts; the youngest infant showed no response. In 10 children, we could demonstrate...... flow during activation. The different response patterns in young children and adults can reflect developmental or behavioral differences. Localization of the activation seemed to be age-dependent. In the older children and the adults, it encompassed the whole length of the calcarine sulcus, whereas it...

  14. Magnetic plasmonic Metamaterials in actively pumped Host Medium and Plasmonic Nanolaser

    Sarychev, A K; Sarychev, Andrey K.; Tartakovsky, Gennady

    2006-01-01

    We consider plasmonic nanoantennas immersed in active host medium. Specifically shaped metal nanoantennas can exhibit strong magnetic properties in the optical spectral range due to the excitation of Magnetic Plasmon Resonance (MPR). A case when a metamaterial comprising such nanoantennas can demonstrate both "left-handiness" and negative permeability in the optical range is considered. We show that high losses predicted for optical "left- handed" materials can be compensated in the gain medium. Gains required to achieve local generation in such magnetic active metamaterials are calculated for real metals. We propose plasmonic nanolaser, where the metal nanoantenna operates like a resonator. The size of the proposed plasmonic laser is much smaller than the wavelength. Therefore, it can serve as a very compact source of EM radiation.

  15. Active Region Filaments Might Harbor Weak Magnetic Fields

    Díaz Baso, C. J.; Martínez González, M. J.; Asensio Ramos, A.

    2016-05-01

    Recent spectropolarimetric observations of active region filaments have revealed polarization profiles with signatures typical of the strong field Zeeman regime. The conspicuous absence in those observations of scattering polarization and Hanle effect signatures was then pointed out by some authors. This was interpreted as either a signature of mixed “turbulent” field components or as a result of optical thickness. In this article, we present a natural scenario to explain these Zeeman-only spectropolarimetric observations of active region (AR) filaments. We propose a two-component model, one on top of the other. Both components have horizontal fields, with the azimuth difference between them being close to 90°. The component that lies lower in the atmosphere is permeated by a strong field of the order of 600 G, while the upper component has much weaker fields, of the order of 10 G. The ensuing scattering polarization signatures of the individual components have opposite signs, so its combination along the line of sight reduces—and even can cancel out—the Hanle signatures, giving rise to an apparent Zeeman-only profile. This model is also applicable to other chromospheric structures seen in absorption above ARs.

  16. MAGNET

    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 ...

  17. MAGNET

    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...

  18. MAGNET

    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 ...

  19. The role of the liver in liver regeneration

    Liver regeneration has been studied almost exclusively in the rat model, and the characteristic response after partial hepatectomy is well established. Large animals have been used to a limited extent, mainly because the measurement of regeneration has been prohibitively expensive. A suitable index of liver regeneration was sought in order to be able to utilise the advantages of a large animal like the pig. Activity of thymidine kinase, which phosphorylates thymidine prior to its incorporation into DNA, was evaluated by comparing it to 14C-thymidine incorporation after partial hepatectomy in the rat model. The changes in thymidine kinase activity correlated well with those in 14C-thymidine incorporation, thus validating use of the former as an index of liver regeneration. This study details a simple and reproducible model - that of 50% partial hepatectomy in the pig - and describes the regenerative response, using thymidine kinase activity as the index of regeneration. Enzyme activity increased on the second and reached a peak on the third post-operative day. The role of the liver in liver regeneration was also investigated by transplanting either a partially hepatectomised or an intact auxiliary liver in such a way that blood flowed through the transplanted liver and into the host liver

  20. Magnetoreception: activated cryptochrome 1a concurs with magnetic orientation in birds

    Nießner, Christine; Denzau, Susanne; Stapput, Katrin; Ahmad, Margaret; Peichl, Leo; Wiltschko, Wolfgang; Wiltschko, Roswitha

    2013-01-01

    The radical pair model proposes that the avian magnetic compass is based on radical pair processes in the eye, with cryptochrome, a flavoprotein, suggested as receptor molecule. Cryptochrome 1a (Cry1a) is localized at the discs of the outer segments of the UV/violet cones of European robins and chickens. Here, we show the activation characteristics of a bird cryptochrome in vivo under natural conditions. We exposed chickens for 30 min to different light regimes and analysed the amount of Cry1a labelled with an antiserum against an epitope at the C-terminus of this protein. The staining after exposure to sunlight and to darkness indicated that the antiserum labels only an illuminated, activated form of Cry1a. Exposure to narrow-bandwidth lights of various wavelengths revealed activated Cry1a at UV, blue and turquoise light. With green and yellow, the amount of activated Cry1a was reduced, and with red, as in the dark, no activated Cry1a was labelled. Activated Cry1a is thus found at all those wavelengths at which birds can orient using their magnetic inclination compass, supporting the role of Cry1a as receptor molecule. The observation that activated Cry1a and well-oriented behaviour occur at 565 nm green light, a wavelength not absorbed by the fully oxidized form of cryptochrome, suggests that a state other than the previously suggested Trp•/FAD• radical pair formed during photoreduction is crucial for detecting magnetic directions. PMID:23966619

  1. Noninvasive transcranial focused ultrasonic-magnetic stimulation for modulating brain oscillatory activity

    Yuan, Yi; Chen, Yudong; Li, Xiaoli

    2016-02-01

    A novel technique, transcranial focused ultrasonic-magnetic stimulation (tFUMS), has been developed for noninvasive brain modulation in vivo. tFUMS has a higher spatial resolution (stimulation on the neuromodulation. The results demonstrate that tFUMS can modulate brain oscillatory activities by stimulating brain tissues.

  2. Cylindrical active coated nano-particles excited by electric and magnetic line sources

    Arslanagic, Samel; Liu, Y.; Malureanu, Radu;

    2011-01-01

    Cylindrical active coated nano-particles comprised of a silica nano-cylinder core covered with a plasmonic nano-shell are investigated with regard to their near- and far-field properties. The source of excitation is taken to be an electric or a magnetic line current, while three different plasmonic...

  3. Molecular Imaging of Activated Platelets Allows the Detection of Pulmonary Embolism with Magnetic Resonance Imaging.

    Heidt, Timo; Ehrismann, Simon; Hövener, Jan-Bernd; Neudorfer, Irene; Hilgendorf, Ingo; Reisert, Marco; Hagemeyer, Christoph E; Zirlik, Andreas; Reinöhl, Jochen; Bode, Christoph; Peter, Karlheinz; von Elverfeldt, Dominik; von Zur Muhlen, Constantin

    2016-01-01

    Early and reliable detection of pulmonary embolism (PE) is critical for improving patient morbidity and mortality. The desire for low-threshold screening for pulmonary embolism is contradicted by unfavorable radiation of currently used computed tomography or nuclear techniques, while standard magnetic resonance imaging still struggles to provide sufficient diagnostic sensitivity in the lung. In this study we evaluate a molecular-targeted contrast agent against activated platelets for non-invasive detection of murine pulmonary thromboembolism using magnetic resonance imaging. By intravenous injection of human thrombin, pulmonary thromboembolism were consistently induced as confirmed by immunohistochemistry of the lung. Magnetic resonance imaging after thrombin injection showed local tissue edema in weighted images which co-localized with the histological presence of pulmonary thromboembolism. Furthermore, injection of a functionalized contrast agent targeting activated platelets provided sensitive evidence of focal accumulation of activated platelets within the edematous area, which, ex vivo, correlated well with the size of the pulmonary embolism. In summary, we here show delivery and specific binding of a functionalized molecular contrast agent against activated platelets for targeting pulmonary thromboembolism. Going forward, molecular imaging may provide new opportunities to increase sensitivity of magnetic resonance imaging for detection of pulmonary embolism. PMID:27138487

  4. Progesterone and peripheral nerve regeneration

    Fei Fan; Haichao Li; Yuwei Wang; Yanglin Zheng; Lianjun Jia; Zhihui Wang

    2006-01-01

    OBJECTIVE: To explore the effect of progesterone on peripheral nerve regeneration.DATA SOURCES: An online search of Medline and OVID databases was under taken to identify articles about progesterone and peripheral nerve regeneration published in English between January 1990 and June 2004 by using the keywords of "peripheral nerve, injury, progesterone, regeneration".STUDY SELECTION: The data were primarily screened, those correlated with progesterone and peripheral nerve regeneration were involved, and their original articles were further searched, the repetitive studies or reviews were excluded.DATA EXTRACTION: Totally 59 articles about progesterone and peripheral nerve regeneration were collected, and 26 of them were involved, the other 33 excluded ones were the repetitive studies or reviews.DATA SYNTHESIS: Recent researches found that certain amount of progesterone could be synthetized in peripheral nervous system, and the expression of progesterone receptor could be found in sensory neurons and Schwann cells. After combined with the receptor, endogenous and exogenous progesterone can accelerate the formation of peripheral nerve myelin sheath, also promote the axonal regeneration.CONCLUSION: Progesterone plays a role in protecting neurons, increasing the sensitivity of nerve tissue to nerve growth factor, and accelerating regeneration of nerve in peripheral nerve regeneration, which provides theoretical references for the treatment of demyelinated disease and nerve injury, as well as the prevention of neuroma, especially that the in vivo level of progesterone should be considered for the elderly people accompanied by neuropathy and patients with congenital luteal phase defect, which is of positive significance in guiding the treatment.

  5. Activity and magnetic field structure of the Sun-like planet-hosting star HD 1237

    Alvarado-Gómez, J. D.; Hussain, G. A. J.; Grunhut, J.; Fares, R.; Donati, J.-F.; Alecian, E.; Kochukhov, O.; Oksala, M.; Morin, J.; Redfield, S.; Cohen, O.; Drake, J. J.; Jardine, M.; Matt, S.; Petit, P.; Walter, F. M.

    2015-10-01

    We analyse the magnetic activity characteristics of the planet-hosting Sun-like star, HD 1237, using HARPS spectro-polarimetric time-series data. We find evidence of rotational modulation of the magnetic longitudinal field measurements that is consistent with our ZDI analysis with a period of 7 days. We investigate the effect of customising the LSD mask to the line depths of the observed spectrum and find that it has a minimal effect on the shape of the extracted Stokes V profile but does result in a small increase in the S/N (~7%). We find that using a Milne-Eddington solution to describe the local line profile provides a better fit to the LSD profiles in this slowly rotating star, which also affects the recovered ZDI field distribution. We also introduce a fit-stopping criterion based on the information content (entropy) of the ZDI map solution set. The recovered magnetic field maps show a strong (+90 G) ring-like azimuthal field distribution and a complex radial field dominating at mid latitudes (~45 degrees). Similar magnetic field maps are recovered from data acquired five months apart. Future work will investigate how this surface magnetic field distribution affeccts the coronal magnetic field and extended environment around this planet-hosting star.

  6. Photospheric and Coronal Observations of Abrupt Magnetic Restructuring in Two Flaring Active Regions

    Petrie, Gordon

    2016-05-01

    For two major X-class flares observed by the Solar Dynamics Observatory (SDO) and the Solar TErrestrial RElations Observatory Ahead (STEREO-A) spacecraft when they were close to quadrature, we compare major, abrupt changes in the photospheric magnetic vector field to changes in the observed coronal magnetic structure during the two flares. The Lorentz force changes in strong photospheric fields within active regions are estimated from time series of SDO Helioseismic and Magnetic Imager (HMI) vector magnetograms. These show that the major changes occurred in each case near the main neutral line of the region and in two neighboring twisted opposite-polarity sunspots. In each case the horizontal parallel field strengthened significantly near the neutral line while the azimuthal field in the sunspots decreased, suggesting that a flux rope joining the two sunspots collapsed across the neutral line with reduced magnetic pressure because of a reduced field twist component. At the same time, the coronal extreme ultraviolet (EUV) loop structure was observed by the Atmospheric Imaging Assembly (AIA) onboard SDO and the Extreme Ultraviolet Imager (EUVI) on STEREO-A to decrease significantly in height during each eruption, discontinuous changes signifying ejection of magnetized plasma, and outward-propagating continuous but abrupt changes consistent with loop contraction. An asymmetry in the observed EUV loop changes during one of the flares matches an asymmetry in the photospheric magnetic changes associated with that flare. The observations are discussed in terms of the well-known tether-cutting and breakout flare initiation models.

  7. Palladium Activated Self-Assembled Monolayer for Magnetics on Silicon Applications

    Anthony, Ricky; Mathúna, Cian Ó.; Rohan, James F.

    Magnetic thin films such as Permalloy (Py) have been extensively used as core material in integrated power magnetic components (micro-inductors and transformers) for their excellent soft magnetic properties. Existing core electrodeposition technology requires sputtered permalloy seed layer. This seed layer etches slowly compared to the electroplated core during magnetic core patterning. In this work, a new electroless deposition process has been developed where samples are activated by palladium to realize a thin catalytic layer on SiO2. Up to 1 μm thick permalloy (∼22% ±3% Fe and ∼78%±3% Ni) is deposited from an in-house developed borane based bath to achieve ∼ 30-35 μOhm-cm resistivities. The magnetic properties of permalloy deposits reveal distinct hysteresis loop with coercivity (∼4.5 Oe). The electroless permalloy over-etch (12 μm) compared with sputtered permalloy seed is found to be negligible (2 μm). This demonstrates the applicability of permalloy electroless deposition as a seed for high yield batch fabrication of magnetics on silicon devices.

  8. Understanding Urban Development Land: Accelerating Regeneration

    Myers, D.; W. Mike; Peter, W

    2003-01-01

    Prolific urbanisation in Europe has lead to phenomenal growth in the geographical size and land use density of towns and cities. Inevitably, over time, the fabric (buildings and infrastructure) of the built environment becomes obsolete and needs replacing. This gives rise to debates relating to regeneration. It has become a political imperative in the UK, and Europe as a whole, to focus development activity on the previously developed sites within existing urban areas. In the UK this is known...

  9. Retinal synaptic regeneration via microfluidic guiding channels

    Ping-Jung Su; Zongbin Liu; Kai Zhang; Xin Han; Yuki Saito; Xiaojun Xia; Kenji Yokoi; Haifa Shen; Lidong Qin

    2015-01-01

    In vitro culture of dissociated retinal neurons is an important model for investigating retinal synaptic regeneration (RSR) and exploring potentials in artificial retina. Here, retinal precursor cells were cultured in a microfluidic chip with multiple arrays of microchannels in order to reconstruct the retinal neuronal synapse. The cultured retinal cells were physically connected through microchannels. Activation of electric signal transduction by the cells through the microchannels was demon...

  10. Role of Transcription Factors in Peripheral Nerve Regeneration

    Patodia, Smriti; Raivich, Gennadij

    2012-01-01

    Following axotomy, the activation of multiple intracellular signaling cascades causes the expression of a cocktail of regeneration-associated transcription factors which interact with each other to determine the fate of the injured neurons. The nerve injury response is channeled through manifold and parallel pathways, integrating diverse inputs, and controlling a complex transcriptional output. Transcription factors form a vital link in the chain of regeneration, converting injury-induced str...

  11. Somatotopical relationships between cortical activity and reflex areas in reflexology: A functional magnetic resonance imaging study

    Nakamaru, Tomomi; MIURA, NAOKI; Fukushima, Ai; Kawashima, Ryuta

    2008-01-01

    We examined the somatotopical relationship between cortical activity and sensory stimulation of reflex areas in reflexology using functional magnetic resonance imaging. Three reflex areas on the left foot, relating to the eye, shoulder, and small intestine were stimulated during the experiment. A statistical analysis showed that reflexological stimulation of the foot reflex areas corresponding to the eye, shoulder, and small intestine activated not only the somatosensory areas corresponding t...

  12. Research of Air-Magnet Active Vibration Isolation System Based on H∞ Control

    Wen Xianglong

    2015-01-01

    Full Text Available Considering the uncertainty of air-magnet active vibration isolation system (AMAVIS, passive vibration isolation was combined with active vibration isolation, which adopted H∞ control strategies. System identification method was used to get the channel model. By adopting mixed sensitivity design strategy, weighting functions were chosen and H∞ controller was designed. Both simulation results and experimental results show AMAVIS based on H∞ control had satisfying effect of vibration reduction in assigned frequency band.

  13. Could a change in magnetic field geometry cause the break in the wind-activity relation?

    Vidotto, A A; Jardine, M; See, V; Petit, P; Boisse, I; Saikia, S Boro; Hebrard, E; Jeffers, S V; Marsden, S C; Morin, J

    2015-01-01

    Wood et al suggested that mass-loss rate is a function of X-ray flux ($\\dot{M} \\propto F_x^{1.34}$) for dwarf stars with $F_x \\lesssim F_{x,6} \\equiv 10^6$ erg cm$^{-2}$ s$^{-1}$. However, more active stars do not obey this relation. These authors suggested that the break at $F_{x,6}$ could be caused by significant changes in magnetic field topology that would inhibit stellar wind generation. Here, we investigate this hypothesis by analysing the stars in Wood et al's sample that had their surface magnetic fields reconstructed through Zeeman-Doppler Imaging (ZDI). Although the solar-like outliers in the $\\dot{M}$ -- $F_x$ relation have higher fractional toroidal magnetic energy, we do not find evidence of a sharp transition in magnetic topology at $F_{x,6}$. To confirm this, further wind measurements and ZDI observations at both sides of the break are required. As active stars can jump between states with highly toroidal to highly poloidal fields, we expect significant scatter in magnetic field topology to exi...

  14. Analytical-HZETRN Model for Rapid Assessment of Active Magnetic Radiation Shielding

    Washburn, S. A.; Blattnig, S. R.; Singleterry, R. C.; Westover, S. C.

    2014-01-01

    The use of active radiation shielding designs has the potential to reduce the radiation exposure received by astronauts on deep-space missions at a significantly lower mass penalty than designs utilizing only passive shielding. Unfortunately, the determination of the radiation exposure inside these shielded environments often involves lengthy and computationally intensive Monte Carlo analysis. In order to evaluate the large trade space of design parameters associated with a magnetic radiation shield design, an analytical model was developed for the determination of flux inside a solenoid magnetic field due to the Galactic Cosmic Radiation (GCR) radiation environment. This analytical model was then coupled with NASA's radiation transport code, HZETRN, to account for the effects of passive/structural shielding mass. The resulting model can rapidly obtain results for a given configuration and can therefore be used to analyze an entire trade space of potential variables in less time than is required for even a single Monte Carlo run. Analyzing this trade space for a solenoid magnetic shield design indicates that active shield bending powers greater than 15 Tm and passive/structural shielding thicknesses greater than 40 g/cm2 have a limited impact on reducing dose equivalent values. Also, it is shown that higher magnetic field strengths are more effective than thicker magnetic fields at reducing dose equivalent.

  15. Ulysses observations of electron and proton components in a magnetic cloud and related wave activity

    Osherovich, V. A.; Fainberg, J.; Stone, R. G.; MacDowall, R. J.; Phillips, J. L.; Balogh, A.

    1995-01-01

    In addition to a smooth rotation of the magnetic field vector, magnetic clouds have a low proton temperature T(sub p). Their expansion in the solar wind leads to depletion and therefore the ion component cools down. It has been shown recently that the electron component in magnetic clouds behaves differently: when the cloud expands, electron temperature Te anti correlates with density and therefore Te increases in the cloud, creating favorable conditions for the rise of ion-acoustic waves. For the magnetic cloud observed by Ulysses on June 10 - 12, 1993 at 4.64 AU at S 32.5 deg, we present observations for both electron and proton components and related plasma wave activity. Our results confirm the anti correlation between T(sub e) and electron density and also exhibit a high ratio of T(sub e)/T(sub P) in the cloud. Since Landau damping is not effective for T(sub e)/T(sub p) much greater than 1, Doppler shifted ion acoustic waves are expected in the cloud. Calculation of ion acoustic wave frequencies in the cloud and comparison with observed wave activity confirm this expectation. As in our previous work, we show that the electron component in the cloud obeys a polytropic law with gamma is less than 1 (gamma approximately equals 0.3-0.4). The dynamics of the magnetic cloud are determined to a large degree by the dominating electron pressure.

  16. A new shunt DC active filter of power supply in a steady high magnetic field facility

    A DC active power filter is an indispensable part in a high power and high stability power supply system, especially in the power supply system of the Steady High Magnetic Field Facility, which requires that the current ripple should be limited to 50 parts per million. In view of the disadvantages of the series DC active power filter and shunt Pulse Width Modulation DC active filter, this paper puts forward a novel DC active filter by combining the advantages of the transistor regulator and the shunt type. The structure and principle of the new shunt linear active filter are introduced. Meanwhile, the design of several key components that construct the new shunt linear active filter is also analyzed. The simulation model and an experimental prototype of the shunt linear active filter are developed, and the results verify that the parameter design is reasonable and the shunt active filter has a good filter effect. (authors)

  17. Regulation of Microtubule Dynamics in Axon Regeneration: Insights from C. elegans [version 1; referees: 3 approved

    Ngang Heok Tang

    2016-04-01

    Full Text Available The capacity of an axon to regenerate is regulated by its external environment and by cell-intrinsic factors. Studies in a variety of organisms suggest that alterations in axonal microtubule (MT dynamics have potent effects on axon regeneration. We review recent findings on the regulation of MT dynamics during axon regeneration, focusing on the nematode Caenorhabditis elegans. In C. elegans the dual leucine zipper kinase (DLK promotes axon regeneration, whereas the exchange factor for Arf6 (EFA-6 inhibits axon regeneration. Both DLK and EFA-6 respond to injury and control axon regeneration in part via MT dynamics. How the DLK and EFA-6 pathways are related is a topic of active investigation, as is the mechanism by which EFA-6 responds to axonal injury. We evaluate potential candidates, such as the MT affinity-regulating kinase PAR-1/MARK, in regulation of EFA-6 and axonal MT dynamics in regeneration.

  18. State of the art of control for magnetic levitation and magnetic bearing and control theory. Active control seigyo riron oyo no saisentan

    Nonami, K. (Chiba University, Chiba (Japan). Faculty of Engineering)

    1993-04-10

    From the viewpoint of control theory which was made known mainly through the papers presented in the international active magnetic bearing conference, survey was made of the latest state of active magnetic levitation and bearing system technology. The active magnetic bearing control system is applied to turbo-molecular pumps. They are analog PID-controlled rigid rotor pumps. Many of them are commonly characterized by five-axis controlled suction type active magnetic bearing. For heightening its performance, a further progress is being made in the following items of R and D: Transition from analog control to digital control using the digital signal processor. Transition from PID-controlled stabilization control to advanced control applying the modern control theory, robust control theory, learning control theory, and disturbance compensation control and other system designs. Active magnetic bearing control system with flexible rotors passing through the high order elastic mode. Active magnetic sensorless bearing by which the control is made by assuming the rotor displacement by the observer theory from the electric current in exciting coil. 37 refs., 11 figs.

  19. MAGNET

    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....

  20. Engineered Theranostic Magnetic Nanostructures: Role of Composition and Surface Coating on Magnetic Resonance Imaging Contrast and Thermal Activation.

    Nandwana, Vikas; Ryoo, Soo-Ryoon; Kanthala, Shanthi; De, Mrinmoy; Chou, Stanley S; Prasad, Pottumarthi V; Dravid, Vinayak P

    2016-03-23

    Magnetic nanostructures (MNS) have emerged as promising functional probes for simultaneous diagnostics and therapeutics (theranostic) applications due to their ability to enhance localized contrast in magnetic resonance imaging (MRI) and heat under external radio frequency (RF) field, respectively. We show that the "theranostic" potential of the MNS can be significantly enhanced by tuning their core composition and architecture of surface coating. Metal ferrite (e.g., MFe2O4) nanoparticles of ∼8 nm size and nitrodopamine conjugated polyethylene glycol (NDOPA-PEG) were used as the core and surface coating of the MNS, respectively. The composition was controlled by tuning the stoichiometry of MFe2O4 nanoparticles (M = Fe, Mn, Zn, ZnxMn1-x) while the architecture of surface coating was tuned by changing the molecular weight of PEG, such that larger weight is expected to result in longer length extended away from the MNS surface. Our results suggest that both core as well as surface coating are important factors to take into consideration during the design of MNS as theranostic agents which is illustrated by relaxivity and thermal activation plots of MNS with different core composition and surface coating thickness. After optimization of these parameters, the r2 relaxivity and specific absorption rate (SAR) up to 552 mM(-1) s(-1) and 385 W/g were obtained, respectively, which are among the highest values reported for MNS with core magnetic nanoparticles of size below 10 nm. In addition, NDOPA-PEG coated MFe2O4 nanostructures showed enhanced biocompatibility (up to [Fe] = 200 μg/mL) and reduced nonspecific uptake in macrophage cells in comparison to other well established FDA approved Fe based MR contrast agents. PMID:26936392

  1. Design and Analysis of a Nested Halbach Permanent Magnet Magnetic Refrigerator

    Tura, Armando

    A technology with the potential to create efficient and compact refrigeration devices is an active magnetic regenerative refrigerator (AMRR). AMRRs exploit the magnetocaloric effect displayed by magnetic materials whereby a reversible temperature change is induced when the material is exposed to a change in applied magnetic field. By using the magnetic materials in a regenerator as the heat storage medium and as the means of work input, one creates an active magnetic regenerator (AMR). Although several laboratory devices have been developed, no design has yet demonstrated the performance, reliability, and cost needed to compete with traditional vapor compression refrigerators. There are many reasons for this and questions remain as to the actual potential of the technology. The objective of the work described in this thesis is to quantify the actual and potential performance of a permanent magnet AMR system. A specific device configuration known as a dual-nested-Halbach system is studied in detail. A laboratory scale device is created and characterized over a wide range of operating parameters. A numerical model of the device is created and validated against experimental data. The resulting model is used to create a cost-minimization tool to analyze the conditions needed to achieve specified cost and efficiency targets. Experimental results include cooling power, temperature span, pumping power and work input. Although the magnetocaloric effect of gadolinium is small, temperature spans up to 30 K are obtained. Analysis of power input shows that the inherent magnetic work is a small fraction of the total work input confirming the assumption that potential cycle efficiencies can be large. Optimization of the device generates a number of areas for improvement and specific results depend upon targeted temperature spans and cooling powers. A competitive cost of cooling from a dual-nested-Halbach configuration is challenging and will depend on the ability to create

  2. Prunetin signals via G-protein-coupled receptor, GPR30(GPER1): Stimulation of adenylyl cyclase and cAMP-mediated activation of MAPK signaling induces Runx2 expression in osteoblasts to promote bone regeneration.

    Khan, Kainat; Pal, Subhashis; Yadav, Manisha; Maurya, Rakesh; Trivedi, Arun Kumar; Sanyal, Sabyasachi; Chattopadhyay, Naibedya

    2015-12-01

    Prunetin is found in red clover and fruit of Prunus avium (red cherry). The effect of prunetin on osteoblast function, its mode of action and bone regeneration in vivo were investigated. Cultures of primary osteoblasts, osteoblastic cell line and HEK293T cells were used for various in vitro studies. Adult female rats received drill-hole injury at the femur diaphysis to assess the bone regenerative effect of prunetin. Prunetin at 10nM significantly (a) increased proliferation and differentiation of primary cultures of osteoblasts harvested from rats and (b) promoted formation of mineralized nodules by bone marrow stromal/osteoprogenitor cells. At this concentration, prunetin did not activate any of the two nuclear estrogen receptors (α and β). However, prunetin triggered signaling via a G-protein-coupled receptor, GPR30/GPER1, and enhanced cAMP levels in osteoblasts. G15, a selective GPR30 antagonist, abolished prunetin-induced increases in osteoblast proliferation, differentiation and intracellular cAMP. In osteoblasts, prunetin up-regulated runt-related transcription factor 2 (Runx2) protein through cAMP-dependent Erk/MAP kinase activation that ultimately resulted in the up-regulation of GPR30. Administration of prunetin at 0.25mg/kg given to rats stimulated bone regeneration at the site of drill hole and up-regulated Runx2 expression in the fractured callus and the effect was comparable to human parathyroid hormone, the only clinically used osteogenic therapy. We conclude that prunetin promotes osteoinduction in vivo and the mechanism is defined by signaling through GPR30 resulting in the up-regulation of the key osteogenic gene Runx2 that in turn up-regulates GPR30. PMID:26345541

  3. Identifying parameters in active magnetic bearing system using LFT formulation and Youla factorization

    Lauridsen, Jonas; Sekunda, André Krabdrup; Santos, Ilmar;

    2015-01-01

    In this paper, a method for identifying uncertain parameters in a rotordynamic system composed of a flexible rotating shaft, rigid discs and two radial active magnetic bearings is presented. Shaft and disc dynamics are mathematically described using a Finite Element (FE) model while magnetic...... of the system matrix A of the full FE model while it is represented as several elements spread over multiple rows and columns of the system matrix of the reduced model. The parametric uncertainty, for both the full and reduced FE model, is represented using Linear Fractional Transformation (LFT). In...

  4. Recent development in noninvasive brain activity measurement by functional magnetic resonance imaging (fMRI)

    fMRI (functional magnetic resonance imaging) is a non-invasive brain imaging technique with which the distribution of neural activity is estimated by measuring local blood flow changes. Blood-oxygenation-level-dependent (BOLD) method measures changes in the density of deoxidized hemoglobin in blood caused by blood flow changes, while other methods have been developed to measure the blood flow changes directly. Effort has been expended to realize a submillimeter spatial resolution by using higher static magnetic field. fMRI has been carried out with various mental tasks, and many important findings have been made on the localization of higher brain functions. (author)

  5. Bucking Coil Implementation on PMT for Active Cancelling of Magnetic Field

    Gogami, T; Bono, J; Baturin, P; Chen, C; Chiba, A; Chiga, N; Fujii, Y; Hashimoto, O; Kawama, D; Maruta, T; Maxwell, V; Mkrtchyan, A; Nagao, S; Nakamura, S N; Reinhold, J; Shichijo, A; Tang, L; Taniya, N; Wood, S A; Ye, Z

    2013-01-01

    Aerogel and water Cerenkov detectors were employed to tag kaons for a lambda hypernuclear spectroscopic experiment which used the (e,e'K+) reaction in experimental Hall C at Jefferson Lab (JLab E05-115). Fringe fields from the kaon spectrometer magnet yielded ~5 Gauss at the photomultiplier tubes (PMT) for these detectors which could not be easily shielded. As this field results in a lowered kaon detection efficiency, we implemented a bucking coil on each photomultiplier tubes to actively cancel this magnetic field, thus maximizing kaon detection efficiency.

  6. The role of active region coronal magnetic field in determining coronal mass ejection propagation direction

    Wang, Rui; Dai, Xinghua; Yang, Zhongwei; Huang, Chong; Hu, Huidong

    2015-01-01

    We study the role of the coronal magnetic field configuration of an active region in determining the propagation direction of a coronal mass ejection (CME). The CME occurred in the active region 11944 (S09W01) near the disk center on 2014 January 7 and was associated with an X1.2 flare. A new CME reconstruction procedure based on a polarimetric technique is adopted, which shows that the CME changed its propagation direction by around 28$^\\circ$ in latitude within 2.5 R$_\\odot$ and 43$^\\circ$ in longitude within 6.5 R$_\\odot$ with respect to the CME source region. This significant non-radial motion is consistent with the finding of M$\\ddot{o}$stl et al. (2015). We use nonlinear force-free field (NLFFF) and potential field source surface (PFSS) extrapolation methods to determine the configurations of the coronal magnetic field. We also calculate the magnetic energy density distributions at different heights based on the extrapolations. Our results show that the active region coronal magnetic field has a strong ...

  7. Magnetic Flux Transport and the Long-Term Evolution of Solar Active Regions

    Ugarte-Urra, Ignacio; Warren, Harry P; Hathaway, David H

    2015-01-01

    With multiple vantage points around the Sun, STEREO and SDO imaging observations provide a unique opportunity to view the solar surface continuously. We use He II 304 A data from these observatories to isolate and track ten active regions and study their long-term evolution. We find that active regions typically follow a standard pattern of emergence over several days followed by a slower decay that is proportional in time to the peak intensity in the region. Since STEREO does not make direct observations of the magnetic field, we employ a flux-luminosity relationship to infer the total unsigned magnetic flux evolution. To investigate this magnetic flux decay over several rotations we use a surface flux transport model, the Advective Flux Transport (AFT) model, that simulates convective flows using a time-varying velocity field and find that the model provides realistic predictions when information about the active region's magnetic field strength and distribution at peak flux is available. Finally, we illust...

  8. Nanocomposites and bone regeneration

    James, Roshan; Deng, Meng; Laurencin, Cato T.; Kumbar, Sangamesh G.

    2011-12-01

    This manuscript focuses on bone repair/regeneration using tissue engineering strategies, and highlights nanobiotechnology developments leading to novel nanocomposite systems. About 6.5 million fractures occur annually in USA, and about 550,000 of these individual cases required the application of a bone graft. Autogenous and allogenous bone have been most widely used for bone graft based therapies; however, there are significant problems such as donor shortage and risk of infection. Alternatives using synthetic and natural biomaterials have been developed, and some are commercially available for clinical applications requiring bone grafts. However, it remains a great challenge to design an ideal synthetic graft that very closely mimics the bone tissue structurally, and can modulate the desired function in osteoblast and progenitor cell populations. Nanobiomaterials, specifically nanocomposites composed of hydroxyapatite (HA) and/or collagen are extremely promising graft substitutes. The biocomposites can be fabricated to mimic the material composition of native bone tissue, and additionally, when using nano-HA (reduced grain size), one mimics the structural arrangement of native bone. A good understanding of bone biology and structure is critical to development of bone mimicking graft substitutes. HA and collagen exhibit excellent osteoconductive properties which can further modulate the regenerative/healing process following fracture injury. Combining with other polymeric biomaterials will reinforce the mechanical properties thus making the novel nano-HA based composites comparable to human bone. We report on recent studies using nanocomposites that have been fabricated as particles and nanofibers for regeneration of segmental bone defects. The research in nanocomposites, highlight a pivotal role in the future development of an ideal orthopaedic implant device, however further significant advancements are necessary to achieve clinical use.

  9. Physiological basis and image processing in functional magnetic resonance imaging: Neuronal and motor activity in brain

    Sharma Rakesh

    2004-05-01

    Full Text Available Abstract Functional magnetic resonance imaging (fMRI is recently developing as imaging modality used for mapping hemodynamics of neuronal and motor event related tissue blood oxygen level dependence (BOLD in terms of brain activation. Image processing is performed by segmentation and registration methods. Segmentation algorithms provide brain surface-based analysis, automated anatomical labeling of cortical fields in magnetic resonance data sets based on oxygen metabolic state. Registration algorithms provide geometric features using two or more imaging modalities to assure clinically useful neuronal and motor information of brain activation. This review article summarizes the physiological basis of fMRI signal, its origin, contrast enhancement, physical factors, anatomical labeling by segmentation, registration approaches with examples of visual and motor activity in brain. Latest developments are reviewed for clinical applications of fMRI along with other different neurophysiological and imaging modalities.

  10. Static magnetic field changes the activity of venom phospholipase of Vipera Lebetina snakes

    The effect of the static magnetic field (SMF) on the phospholipid activity of the class-A snake venom is studied. The Vipera Lebetina snake venom was subjected during 10 days to 30 minute impact of the CMF daily. It is established that increase in the phospholipase A1 and A2 approximately by 21 and 32 % correspondingly and in the phosphodiesterase C - by 33 % was observed. The decrease in the total protein level of the snake venom by 31.6 ± 2.2 % was noted thereby. It may be assumed that the described phospholipase and phosphoesterase changes may lead to essential shifts in the total metabolic activity of cells and organism as a whole. The activity index of these ferments may serve as an indicator of changes in the environmental magnetic field

  11. Analysis on Dynamic Performance for Active Magnetic Bearing—Rotor System

    YANHui-yan; WANGXi-ping; 等

    2001-01-01

    In the application of active magnetic bearings(AMB),one of the key problems to be solved is the safety and stabiltiy in the sense of rotor dynamics,The project related to the present paper deals with the method for analyzing bearing rotor systems with high rotation speed and specially supported by active magnetic bearings,and studies its rotor dynamics performance,including calculation of the natural frequencies with their distribution characteristics,and the critical speeds of the system.one of the targets of this project is to formulate a theory and method valid for the analysis of the dynamic performance of the active magntic bearing-rotor systemby combining the traditional theory and method of rotor dynamics with the analytical theory and design method based on modern control theory of the AMB system.

  12. Effect of solar and magnetic activity on VHF scintillations near the equatorial anomaly crest

    R. P. Singh

    2004-09-01

    Full Text Available The VHF amplitude scintillation recorded during the period January 1991 to December 1993 in the declining phase of a solar cycle and April 1998 to December 1999 in the ascending phase of the next solar cycle at Varanasi (geogr. lat.=25.3°, long.=83.0°, dip=37°N have been analyzed to study the behavior of ionospheric irregularities during active solar periods and magnetic storms. It is shown that irregularities occur at arbitrary times and may last for <30min. A rise in solar activity increases scintillations during winter (November-February and near equinoxes (March-April; September-October, whereas it depresses the scintillations during the summer (May-July. In general, the role of magnetic activity is to suppress scintillations in the pre-midnight period and to increase it in the post-midnight period during equinox and winter seasons, whilst during summer months the effect is reversed. The pre-midnight scintillation is sometimes observed when the main phase of Dst corresponds to the pre-midnight period. The annual variation shows suppression of scintillations on disturbed days, both during pre-midnight and post-midnight period, which becomes more effective during years of high solar activity. It is observed that for magnetic storms for which the recovery phase starts post-midnight, the probability of occurrence of irregularities is enhanced during this time. If the magnetic storm occurred during daytime, then the probability of occurrence of scintillations during the night hours is decreased. The penetration of magnetospheric electric fields to the magnetic equator affects the evolution of low-latitude irregularities. A delayed disturbance dynamo electric field also affects the development of irregularities.

  13. Specific capture of the hydrolysate on magnetic beads for sensitive detecting plant vacuolar processing enzyme activity.

    Zhou, Jun; Cheng, Meng; Zeng, Lizhang; Liu, Weipeng; Zhang, Tao; Xing, Da

    2016-05-15

    Conventional plant protease detection always suffers from high background interference caused by the complex coloring metabolites in plant cells. In this study, a bio-modified magnetic beads-based strategy was developed for sensitive and quantitative detection of plant vacuolar processing enzyme (VPE) activity. Cleavage of the peptide substrate (ESENCRK-FITC) after asparagine residue by VPE resulted in the 2-cyano-6-amino-benzothiazole (CABT)-functionalized magnetic beads capture of the severed substrate CRK-FITC via a condensation reaction between CABT and cysteine (Cys). The catalytic activity was subsequently obtained by the confocal microscopy imaging and flow cytometry quantitative analysis. The sensor system integrated advantages of (i) the high efficient enrichment and separation capabilities of magnetic beads and (ii) the catalyst-free properties of the CABT-Cys condensation reaction. It exhibited a linear relationship between the fluorescence signal and the concentration of severed substrate in the range of 10-600 pM. The practical results showed that, compared with normal growth conditions, VPE activity was increased by 2.7-fold (307.2 ± 25.3 μM min(-1)g(-1)) upon cadmium toxicity stress. This platform effectively overcame the coloring metabolites-caused background interference, showing fine applicability for the detection of VPE activity in real samples. The strategy offers great sensitivity and may be further extended to other protease activity detection. PMID:26797250

  14. Computer aided design of digital controller for radial active magnetic bearings

    Cai, Zhong; Shen, Zupei; Zhang, Zuming; Zhao, Hongbin

    1992-01-01

    A five degree of freedom Active Magnetic Bearing (AMB) system is developed which is controlled by digital controllers. The model of the radial AMB system is linearized and the state equation is derived. Based on the state variables feedback theory, digital controllers are designed. The performance of the controllers are evaluated according to experimental results. The Computer Aided Design (CAD) method is used to design controllers for magnetic bearings. The controllers are implemented with a digital signal processing (DSP) system. The control algorithms are realized with real-time programs. It is very easy to change the controller by changing or modifying the programs. In order to identify the dynamic parameters of the controlled magnetic system, a special experiment was carried out. Also, the online Recursive Least Squares (RLS) parameter identification method is studied. It can be realized with the digital controllers. Online parameter identification is essential for the realization of an adaptive controller.

  15. The magnetic fields at the surface of active single G-K giants

    Aurière, M.; Konstantinova-Antova, R.; Charbonnel, C.; Wade, G. A.; Tsvetkova, S.; Petit, P.; Dintrans, B.; Drake, N. A.; Decressin, T.; Lagarde, N.; Donati, J.-F.; Roudier, T.; Lignières, F.; Schröder, K.-P.; Landstreet, J. D.; Lèbre, A.; Weiss, W. W.; Zahn, J.-P.

    2015-02-01

    Aims: We investigate the magnetic field at the surface of 48 red giants selected as promising for detection of Stokes V Zeeman signatures in their spectral lines. In our sample, 24 stars are identified from the literature as presenting moderate to strong signs of magnetic activity. An additional 7 stars are identified as those in which thermohaline mixing appears not to have occured, which could be due to hosting a strong magnetic field. Finally, we observed 17 additional very bright stars which enable a sensitive search to be performed with the spectropolarimetric technique. Methods: We use the spectropolarimeters Narval and ESPaDOnS to detect circular polarization within the photospheric absorption lines of our targets. We treat the spectropolarimetric data using the least-squares deconvolution method to create high signal-to-noise ratio mean Stokes V profiles. We also measure the classical S-index activity indicator for the Ca ii H&K lines, and the stellar radial velocity. To infer the evolutionary status of our giants and to interpret our results, we use state-of-the-art stellar evolutionary models with predictions of convective turnover times. Results: We unambiguously detect magnetic fields via Zeeman signatures in 29 of the 48 red giants in our sample. Zeeman signatures are found in all but one of the 24 red giants exhibiting signs of activity, as well as 6 out of 17 bright giant stars. However no detections were obtained in the 7 thermohaline deviant giants. The majority of the magnetically detected giants are either in the first dredge up phase or at the beginning of core He burning, i.e. phases when the convective turnover time is at a maximum: this corresponds to a "magnetic strip" for red giants in the Hertzsprung-Russell diagram. A close study of the 16 giants with known rotational periods shows that the measured magnetic field strength is tightly correlated with the rotational properties, namely to the rotational period and to the Rossby number Ro

  16. Magnet Architectures and Active Radiation Shielding Study - SR2S Workshop

    Westover, Shane; Meinke, Rainer; Burger, William; Ilin, Andrew; Nerolich, Shaun; Washburn, Scott

    2014-01-01

    Analyze new coil configurations with maturing superconductor technology -Develop vehicle-level concept solutions and identify engineering challenges and risks -Shielding performance analysis Recent advances in superconducting magnet technology and manufacturing have opened the door for re-evaluating active shielding solutions as an alternative to mass prohibitive passive shielding.Publications on static magnetic field environments and its bio-effects were reviewed. Short-term exposure information is available suggesting long term exposure may be okay. Further research likely needed. center dotMagnetic field safety requirements exist for controlled work environments. The following effects have been noted with little noted adverse effects -Magnetohydrodynamic (MHD) effects on ionized fluids (e.g. blood) creating an aortic voltage change -MHD interaction elevates blood pressure (BP) center dot5 Tesla equates to 5% BP elevation -Prosthetic devises and pacemakers are an issue (access limit of 5 gauss).

  17. Magnetic Properties and Activity of Pt-Er/γ-Al2O3 Catalysts

    2006-01-01

    A series of Pt-Er/γ-Al2O3 catalysts containing 0.5%(mass fraction) platinum and 0.05%-1.5% Er were prepared by impregnation of γ-Al2O3 supported with different concentrations of erbium chloride solution. The surface properties of the catalysts were studied by methods of temperature programmed reduction and temperature programmed desorption. The magnetic behavior of Pt-Er-γ-Al2O3 catalysts were studied with a Faraday magnetic balance and the results show that the addition of Er can affect the surface properties, the catalytic activities, and magnetic behavior of the reforming catalysts. It is found that there is a corresponding relationship between the susceptibility and selectivity of Pt-Er-γ-Al2O3 catalysts. The experimental results show that Er plays the role of electron promoter.

  18. Design optimization of a 0.1-ton/day active magnetic regenerative hydrogen liquefier

    Zhang, L.; Sherif, S. A.; DeGregoria, A. J.; Zimm, C. B.; Veziroglu, T. N.

    2000-04-01

    A design optimization procedure of a 0.1-ton/day active magnetic regenerative (AMR) hydrogen liquefier model is described. The liquefier is proposed for the industrial liquid hydrogen market with overall efficiency being the primary measure of performance. This performance is described here in terms of particle size, bed length, and inter-stage temperature. Efficiency comparable to larger gas cycle plants is predicted. The magnetic liquefier may be modified to operate as a two-stage magnetic refrigerator between 77 and 20 K with high efficiency. The paper describes an optimization method as applied to the design of a two-stage AMR hydrogen liquefier and presents the associated results. A five-parameter optimization process is performed since there are five changeable parameters; the low- and high-stage particle sizes, the low- and high-stage bed lengths, and the inter-stage temperature. Model results are presented and compared with experimental results of an actual liquefier.

  19. Recent perspectives in solar physics - Elemental composition, coronal structure and magnetic fields, solar activity

    Newkirk, G., Jr.

    1975-01-01

    Elemental abundances in the solar corona are studied. Abundances in the corona, solar wind and solar cosmic rays are compared to those in the photosphere. The variation in silicon and iron abundance in the solar wind as compared to helium is studied. The coronal small and large scale structure is investigated, emphasizing magnetic field activity and examining cosmic ray generation mechanisms. The corona is observed in the X-ray and EUV regions. The nature of coronal transients is discussed with emphasis on solar-wind modulation of galactic cosmic rays. A schematic plan view of the interplanetary magnetic field during sunspot minimum is given showing the presence of magnetic bubbles and their concentration in the region around 4-5 AU by a fast solar wind stream.

  20. Remote activation of the Wnt/β-catenin signalling pathway using functionalised magnetic particles.

    Michael Rotherham

    Full Text Available Wnt signalling pathways play crucial roles in developmental biology, stem cell fate and tissue patterning and have become an attractive therapeutic target in the fields of tissue engineering and regenerative medicine. Wnt signalling has also been shown to play a role in human Mesenchymal Stem Cell (hMSC fate, which have shown potential as a cell therapy in bone and cartilage tissue engineering. Previous work has shown that biocompatible magnetic nanoparticles (MNP can be used to stimulate specific mechanosensitive membrane receptors and ion channels in vitro and in vivo. Using this strategy, we determined the effects of mechano-stimulation of the Wnt Frizzled receptor on Wnt pathway activation in hMSC. Frizzled receptors were tagged using anti-Frizzled functionalised MNP (Fz-MNP. A commercially available oscillating magnetic bioreactor (MICA Biosystems was used to mechanically stimulate Frizzled receptors remotely. Our results demonstrate that Fz-MNP can activate Wnt/β-catenin signalling at key checkpoints in the signalling pathway. Immunocytochemistry indicated nuclear localisation of the Wnt intracellular messenger β-catenin after treatment with Fz-MNP. A Wnt signalling TCF/LEF responsive luciferase reporter transfected into hMSC was used to assess terminal signal activation at the nucleus. We observed an increase in reporter activity after treatment with Fz-MNP and this effect was enhanced after mechano-stimulation using the magnetic array. Western blot analysis was used to probe the mechanism of signalling activation and indicated that Fz-MNP signal through an LRP independent mechanism. Finally, the gene expression profiles of stress response genes were found to be similar when cells were treated with recombinant Wnt-3A or Fz-MNP. This study provides proof of principle that Wnt signalling and Frizzled receptors are mechanosensitive and can be remotely activated in vitro. Using magnetic nanoparticle technology it may be possible to modulate

  1. MAGNET

    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...

  2. MAGNET

    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...

  3. Tissue regenerating functions of coagulation factor XIII

    Soendergaard, C; Kvist, P H; Seidelin, J B;

    2013-01-01

    The protransglutaminase factor XIII (FXIII) has recently gained interest within the field of tissue regeneration, as it has been found that FXIII significantly influences wound healing by exerting a multitude of functions. It supports haemostasis by enhancing platelet adhesion to damaged endothel......The protransglutaminase factor XIII (FXIII) has recently gained interest within the field of tissue regeneration, as it has been found that FXIII significantly influences wound healing by exerting a multitude of functions. It supports haemostasis by enhancing platelet adhesion to damaged...... endothelium, and by its cross-linking activity it stabilizes the formed fibrin clot. Furthermore, FXIII limits bacterial dissemination from the wound and incorporates macromolecules of importance for cellular infiltration supporting cell migration and survival. FXIII-mediated complex formation of the VEGF...

  4. MAGNETIC STRUCTURE PRODUCING X- AND M-CLASS SOLAR FLARES IN SOLAR ACTIVE REGION 11158

    We study the three-dimensional magnetic structure of the solar active region 11158, which produced one X-class and several M-class flares on 2011 February 13-16. We focus on the magnetic twist in four flare events, M6.6, X2.2, M1.0, and M1.1. The magnetic twist is estimated from the nonlinear force-free field extrapolated from the vector fields obtained from the Helioseismic and Magnetic Imager on board the Solar Dynamic Observatory using the magnetohydrodynamic relaxation method developed by Inoue et al. We found that strongly twisted lines ranging from half-turn to one-turn twists were built up just before the M6.6 and X2.2 flares and disappeared after that. Because most of the twists remaining after these flares were less than a half-turn twist, this result suggests that the buildup of magnetic twist over the half-turn twist is a key process in the production of large flares. On the other hand, even though these strong twists were also built up just before the M1.0 and M1.1 flares, most of them remained afterward. Careful topological analysis before the M1.0 and M1.1 flares shows that the strongly twisted lines were surrounded mostly by the weakly twisted lines formed in accordance with the clockwise motion of the positive sunspot, whose footpoints are rooted in strong magnetic flux regions. These results imply that these weakly twisted lines might suppress the activity of the strongly twisted lines in the last two M-class flares.

  5. On the Current Solar Magnetic Activity in the Light of Its Behaviour During the Holocene

    Inceoglu, F.; Simoniello, R.; Knudsen, M. F.; Karoff, C.; Olsen, J.; Turck-Chièze, S.

    2016-01-01

    Solar modulation potential (SMP) reconstructions based on cosmogenic nuclide records reflect changes in the open solar magnetic field and can therefore help us obtain information on the behaviour of the open solar magnetic field over the Holocene period. We aim at comparing the Sun's large-scale magnetic field behaviour over the last three solar cycles with variations in the SMP reconstruction through the Holocene epoch. To achieve these objectives, we use the IntCal13 14C data to investigate distinct patterns in the occurrences of grand minima and maxima during the Holocene period. We then check whether these patterns might mimic the recent solar magnetic activity by investigating the evolution of the energy in the Sun's large-scale dipolar magnetic field using the Wilcox Solar Observatory data. The cosmogenic radionuclide data analysis shows that {≈} 71 % of grand maxima during the period from 6600 BC to 1650 AD were followed by a grand minimum. The characteristics of the occurrences of grand maxima and minima are consistent with the scenario in which the dynamical non-linearity induced by the Lorentz force leads the Sun to act as a relaxation oscillator. This finding implies that the probability for these events to occur is non-uniformly distributed in time, as there is a memory in their driving mechanism, which can be identified via the back-reaction of the Lorentz force.

  6. On the current solar magnetic activity in the light of its behaviour during the Holocene

    Inceoglu, F; Knudsen, M F; Karoff, C; Olsen, J; Turck-Chièze, S

    2015-01-01

    Solar modulation potential (SMP) reconstructions based on cosmogenic nuclide records reflect changes in the open solar magnetic field and can therefore help us obtain information on the behaviour of the open solar magnetic field over the Holocene period. We aim at comparing the Sun's large-scale magnetic field behaviour over the last three solar cycles with variations in the SMP reconstruction through the Holocene epoch. To achieve these objectives, we use the IntCal13 $^{14}$C data to investigate distinct patterns in the occurrences of grand minima and maxima during the Holocene period. We then check whether these patterns might mimic the recent solar magnetic activity by investigating the evolution of the energy in the Sun's large-scale dipolar magnetic field using the Wilcox Solar Observatory data. The cosmogenic radionuclide data analysis shows that $\\sim$71\\% of grand maxima during the period from 6600 BC to 1650 AD were followed by a grand minimum. The occurrence characteristics of grand maxima and mini...

  7. Muscle regeneration in mitochondrial myopathies

    Krag, T O; Hauerslev, S; Jeppesen, T D;

    2013-01-01

    Mitochondrial myopathies cover a diverse group of disorders in which ragged red and COX-negative fibers are common findings on muscle morphology. In contrast, muscle degeneration and regeneration, typically found in muscular dystrophies, are not considered characteristic features of mitochondrial...... myopathies. We investigated regeneration in muscle biopsies from 61 genetically well-defined patients affected by mitochondrial myopathy. Our results show that the perturbed energy metabolism in mitochondrial myopathies causes ongoing muscle regeneration in a majority of patients, and some were even affected...

  8. Axonal regeneration through arterial grafts.

    Anderson, P. N.; Turmaine, M.

    1986-01-01

    The left common peroneal nerves of adult inbred mice were severed and allowed to regenerate through the lumina of Y-shaped tubes comprising grafts of abdominal aorta and its bifurcation. Very little regeneration took place within the grafts unless the distal nerve stump was inserted into one limb of the Y-tube. Using syngeneic grafts virtually all the axons regenerating through the lumen grew down the limb of the Y-tube containing the distal nerve. Using non-syngeneic grafts, however, a subst...

  9. NiFe2O4/activated carbon nanocomposite as magnetic material from petcoke

    Nickel ferrite (NiFe2O4) was supported on activated carbon (AC) from petroleum coke (petcoke). Potassium hydroxide (KOH) was employed with petcoke to produce activated carbon. NiFe2O4 were synthesized using PEG-Oleic acid assisted hydrothermal method. The structural and magnetic properties were determined using thermogravimetric and differential thermal analysis (TGA–DTA), X-ray diffraction (XRD), Fourier Transform Infrared (IR-FT), surface area (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). XRD analysis revealed the cubic spinel structure and ferrite phase with high crystallinity. IR-FT studies showed that chemical modification promoted the formation of surface oxygen functionalities. Morphological investigation by SEM showed conglomerates of spherical nanoparticles with an average particle size of 72 nm and TEM showed the formation of NiFe2O4/carbon nanofibers. Chemical modification and activation temperature of 800 °C prior to activation dramatically increased the BET surface area of the resulting activated carbon to 842.4 m2/g while the sulfur content was reduced from 6 to 1%. Magnetic properties of nanoparticles show strong dependence on the particle size. - Highlights: • TEM showed the formation of NiFe2O4/carbon nanofibers. • Nanoparticles were supported on the activated carbon from petcoke. • Activation dramatically increased the BET surface area to 842 m2/g. • Magnetic properties show strong dependence on the particle size. • Sulphur content was reduced from 6 to 1% with the petcoke activation

  10. Minimalist coupled evolution model for stellar X-ray activity, rotation, mass loss, and magnetic field

    Blackman, Eric G.; Owen, James E.

    2016-05-01

    Late-type main-sequence stars exhibit an X-ray to bolometric flux ratio that depends on {tilde{R}o}, the ratio of rotation period to convective turnover time, as {tilde{R}o}^{-ζ } with 2 ≤ ζ ≤ 3 for {tilde{R}o} > 0.13, but saturates with |ζ| rates and X-ray activity. The unsaturated stars have magnetic fields and rotation speeds that scale roughly with the square root of their age, though possibly flattening for stars older than the Sun. The connection between faster rotators, stronger fields, and higher activity has been established observationally, but a theory for the unified time-evolution of X-ray luminosity, rotation, magnetic field and mass loss that captures the above trends has been lacking. Here we derive a minimalist holistic framework for the time evolution of these quantities built from combining a Parker wind with new ingredients: (1) explicit sourcing of both the thermal energy launching the wind and the X-ray luminosity via dynamo produced magnetic fields; (2) explicit coupling of X-ray activity and mass-loss saturation to dynamo saturation (via magnetic helicity build-up and convection eddy shredding); (3) use of coronal equilibrium to determine how magnetic energy is divided into wind and X-ray contributions. For solar-type stars younger than the Sun, we infer conduction to be a subdominant power loss compared to X-rays and wind. For older stars, conduction is more important, possibly quenching the wind and reducing angular momentum loss. We focus on the time evolution for stars younger than the Sun, highlighting what is possible for further generalizations. Overall, the approach shows promise towards a unified explanation of all of the aforementioned observational trends.

  11. Self-Assembled Complexes of Horseradish Peroxidase with Magnetic Nanoparticles Showing Enhanced Peroxidase Activity

    Corgié, Stéphane C.

    2012-02-15

    Bio-nanocatalysts (BNCs) consisting of horseradish peroxidase (HRP) self-assembled with magnetic nanoparticles (MNPs) enhance enzymatic activity due to the faster turnover and lower inhibition of the enzyme. The size and magnetization of the MNPs affect the formation of the BNCs, and ultimately control the activity of the bound enzymes. Smaller MNPs form small clusters with a low affinity for the HRP. While the turnover for the bound fraction is drastically increased, there is no difference in the H 2O 2 inhibitory concentration. Larger MNPs with a higher magnetization aggregate in larger clusters and have a higher affinity for the enzyme and a lower substrate inhibition. All of the BNCs are more active than the free enzyme or the MNPs (BNCs > HRP ≤laquo; MNPs). Since the BNCs show surprising resilience in various reaction conditions, they may pave the way towards new hybrid biocatalysts with increased activities and unique catalytic properties for magnetosensitive enzymatic reactions. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Magnetic Systems Triggering the M6.6-class Solar Flare in NOAA Active Region 11158

    Toriumi, Shin; Bamba, Yumi; Kusano, Kanya; Imada, Shinsuke; Inoue, Satoshi

    2013-01-01

    We report a detailed event analysis on the M6.6-class flare in the active region (AR) NOAA 11158 on 2011 February 13. AR 11158, which consisted of two major emerging bipoles, showed prominent activities including one X- and several M-class flares. In order to investigate the magnetic structures related to the M6.6 event, particularly the formation process of a flare-triggering magnetic region, we analyzed multiple spacecraft observations and numerical results of a flare simulation. We observed that, in the center of this quadrupolar AR, a highly sheared polarity inversion line (PIL) was formed through proper motions of the major magnetic elements, which built a sheared coronal arcade lying over the PIL. The observations lend support to the interpretation that the target flare was triggered by a localized magnetic region that had an intrusive structure, namely a positive polarity penetrating into a negative counterpart. The geometrical relationship between the sheared coronal arcade and the triggering region w...

  13. Design and implement for control system of active magnetic bearings based on DSP

    Cao, Jie; Cao, Lihong

    2005-12-01

    Magnetic-bearings, which support shafts with magnetic levitation rather than mechanical contact, have been in industrial use for decades. Recent technological developments, especially in digital processing and control, have made magnetic bearings a more-robust and cost-effective design solution than ever. The dynamic characteristic of electromagnetic bearing depends upon adopted controller; the active control can makes the electromagnetic bearings to realize complex control and special control. With the development of signal processing technology and modern control theory, the main parts of the control system are the digital signal-processing (DSP) electronics, a power supply, and amplifiers. An Active Magnetic Bearing (AMB) controller is mainly discussed in the paper, which is to be solved to realize this flexible control by hardware design based on DSP using TMS320C32 processor. It is proved by experiment that this kind of controller can optimize for this system, improve its stability and also have a very important referential value on the further study of AMB system.

  14. Lightweight Magnetic Cooler With a Reversible Circulator

    Chen, Weibo; McCormick, John

    2011-01-01

    A design of a highly efficient and lightweight space magnetic cooler has been developed that can continuously provide remote/distributed cooling at temperatures in the range of 2 K with a heat sink at about 15 K. The innovative design uses a cryogenic circulator that enables the cooler to operate at a high cycle frequency to achieve a large cooling capacity. The ability to provide remote/distributed cooling not only allows flexible integration with a payload and spacecraft, but also reduces the mass of the magnetic shields needed. The active magnetic regenerative refrigerator (AMRR) system is shown in the figure. This design mainly consists of two identical magnetic regenerators surrounded by their superconducting magnets and a reversible circulator. Each regenerator also has a heat exchanger at its warm end to reject the magnetization heat to the heat sink, and the two regenerators share a cold-end heat exchanger to absorb heat from a cooling target. The circulator controls the flow direction, which cycles in concert with the magnetic fields, to facilitate heat transfer. Helium enters the hot end of the demagnetized column, is cooled by the refrigerant, and passes into the cold-end heat exchanger to absorb heat. The helium then enters the cold end of the magnetized column, absorbing heat from the refrigerant, and enters the hot-end heat exchanger to reject the magnetization heat. The efficient heat transfer in the AMRR allows the system to operate at a relatively short cycle period to achieve a large cooling power. The key mechanical components in the magnetic cooler are the reversible circulator and the magnetic regenerators. The circulator uses non-contacting, self-acting gas bearings and clearance seals to achieve long life and vibration- free operation. There are no valves or mechanical wear in this circulator, so the reliability is predicted to be very high. The magnetic regenerator employs a structured bed configuration. The core consists of a stack of thin

  15. Enhanced regeneration of degraded polymer solar cells by thermal annealing

    The degradation and thermal regeneration of poly(3-hexylethiophene) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and P3HT:indene-C60 bisadduct (ICBA) polymer solar cells, with Ca/Al and Ca/Ag cathodes and indium tin oxide/poly(ethylene-dioxythiophene):polystyrene sulfonate anode have been investigated. Degradation occurs via a combination of three primary pathways: (1) cathodic oxidation, (2) active layer phase segregation, and (3) anodic diffusion. Fully degraded devices were subjected to thermal annealing under inert atmosphere. Degraded solar cells possessing Ca/Ag electrodes were observed to regenerate their performance, whereas solar cells having Ca/Al electrodes exhibited no significant regeneration of device characteristics after thermal annealing. Moreover, the solar cells with a P3HT:ICBA active layer exhibited enhanced regeneration compared to P3HT:PCBM active layer devices as a result of reduced changes to the active layer morphology. Devices combining a Ca/Ag cathode and P3HT:ICBA active layer demonstrated ∼50% performance restoration over several degradation/regeneration cycles

  16. 新型微波技术再生载甲苯活化秸秆炭%Regeneration of toluene using microwave heating method on wheat straw activated biochar

    冒海燕; 周定国; Zaher Hashisho; 汪孙国; 陈恒; 王海燕

    2012-01-01

    Wheat straw activated biochar prepared by the microwave heating was used as the ad- sorbent in this study, with generation rate above 99% a comparison of microwave and conductive heating methods on heating time, generation rate and energy consumption for the regeneration of toluene from wheat straw activated biochar was conducted. Experimental results show that the adsorption capacity is unchanged (33 %) compared with original wheat straw activated biochar for both microwave and conductive heating over 5 cycles. Microwave heating with constant power consumes the shortest heating time of 1 rain for toluene, while the time for microware heating with constant temperature and conductive heating is 10 min and 120 min respectively. The energy consumption of microwave heating with constant power of 600 W and constant temperature of 150 ℃ is only 4.5 kJ/g and 9.0 kJ/g respectively but 36 kJ/g for conductive heating method. The microwave heating method could be an energy-efficient, resourceful and efficient regeneration technique for wheat straw activated biochar. 4 tabs, 3 figs, 11 refs.%采用微波加热制备的活化秸秆炭作为吸附剂,通过微波法和电加热法对载甲苯活化秸秆炭进行再生。在确保再生率99%以上的前提下,测定了这两种方法的加热时间、再生效率和能耗等参数。结果表明:经过5次吸附-微波辐射再生之后,吸附量基本保持原有新鲜活化秸秆炭吸附量的为33%;恒功率微波加热法、恒温微波加热法和电加热法所需要的时间分别为1、10和120min;从能耗角度看,微波再生法恒功率(600W)和恒温(150℃)的能耗分别为4.5和9.0kJ/g,而电加热法的能耗则为36kJ/g。因此,微波再生法是一种节能、环保和高效的再生方法,为工业化应用奠定了基础数据。

  17. Regenerable Contaminant Removal System Project

    National Aeronautics and Space Administration — The Regenerable Contaminant Removal System (RCRS) is an innovative method to remove sulfur and halide compounds from contaminated gas streams to part-per-billion...

  18. MAGNET

    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...

  19. MAGNET

    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 ...

  20. Impact of frequency switching on the efficiency of a fully suspended active magnetic bearing system

    Gouws, Rupert

    2012-01-01

    Due to the rising energy (and electricity) cost it is essential that an active magnetic bearing (AMB) system is operated as efficiently as possible. Frequency switching caused by an external source can cause an AMB system to operate at a higher than expected energy level and lower than expected efficiency. The purpose of this paper is therefore to investigate the impact of frequency switching (caused by an external source) on the efficiency of a fully suspended AMB system. The shaft of the fu...