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1

A comparative evaluation of the effect of internet-based CME delivery format on satisfaction, knowledge and confidence  

PubMed Central

Background Internet-based instruction in continuing medical education (CME) has been associated with favorable outcomes. However, more direct comparative studies of different Internet-based interventions, instructional methods, presentation formats, and approaches to implementation are needed. The purpose of this study was to conduct a comparative evaluation of two Internet-based CME delivery formats and the effect on satisfaction, knowledge and confidence outcomes. Methods Evaluative outcomes of two differing formats of an Internet-based CME course with identical subject matter were compared. A Scheduled Group Learning format involved case-based asynchronous discussions with peers and a facilitator over a scheduled 3-week delivery period. An eCME On Demand format did not include facilitated discussion and was not based on a schedule; participants could start and finish at any time. A retrospective, pre-post evaluation study design comparing identical satisfaction, knowledge and confidence outcome measures was conducted. Results Participants in the Scheduled Group Learning format reported significantly higher mean satisfaction ratings in some areas, performed significantly higher on a post-knowledge assessment and reported significantly higher post-confidence scores than participants in the eCME On Demand format that was not scheduled and did not include facilitated discussion activity. Conclusions The findings support the instructional benefits of a scheduled delivery format and facilitated asynchronous discussion in Internet-based CME.

2010-01-01

2

A comparative evaluation of the effect of internet-based CME delivery format on satisfaction, knowledge and confidence  

Microsoft Academic Search

BACKGROUND: Internet-based instruction in continuing medical education (CME) has been associated with favorable outcomes. However, more direct comparative studies of different Internet-based interventions, instructional methods, presentation formats, and approaches to implementation are needed. The purpose of this study was to conduct a comparative evaluation of two Internet-based CME delivery formats and the effect on satisfaction, knowledge and confidence outcomes. METHODS:

Vernon R Curran; Lisa J Fleet; Fran Kirby

2010-01-01

3

Rapid CME Cavity Formation and Expansion  

NASA Astrophysics Data System (ADS)

A cavity is supposed to be a general feature of well-developed CMEs at the stage they can be imaged by white-light coronagraphs (in the outer corona and solar wind). The cavity is interpreted as the cross section of the CME flux rope in the plane of sky. Preexisting cavities are observed around some quiescent erupting prominences, but usually not in active regions. Observations of CME cavities in the inner corona, where most of them appear to form, have become possible only with the STEREO and SDO missions. These reveal a very rapid formation and expansion of "EUV cavities" in fast and impulsively commencing eruptions early in the phase of main CME acceleration and impulsive flare rise. Different from the white-light observations, the EUV cavity initially appears to be larger than the CME flux rope. However, it evolves into the white-light cavity subsequently. MHD simulations of flux rope eruptions conform to this picture of initially larger cavity but subsequently approaching cavity and flux rope size. The initial expansion of ambient flux can be understood as a "reverse pinch effect", driven by decreasing flux rope current as the rope rises.

Kliem, Bernhard; Forbes, Terry G.; Patsourakos, Spiros; Vourlidas, Angelos

2014-06-01

4

CME Theory and Models  

Microsoft Academic Search

This chapter provides an overview of current efforts in the theory and modeling of CMEs. Five key areas are discussed: (1)\\u000a CME initiation; (2) CME evolution and propagation; (3) the structure of interplanetary CMEs derived from flux rope modeling;\\u000a (4) CME shock formation in the inner corona; and (5) particle acceleration and transport at CME driven shocks. In the section

T. G. Forbes; J. A. Linker; J. Chen; C. Cid; J. Kóta; M. A. Lee; G. Mann; Z. Mikic; M. S. Potgieter; J. M. Schmidt; G. L. Siscoe; R. Vainio; S. K. Antiochos; P. Riley

2006-01-01

5

Social Interaction and Participation: Formative Evaluation of Online CME Modules  

ERIC Educational Resources Information Center

Introduction: This exploratory study examines Canadian physicians' participation in online social activities and learning discussions, perceptions of online social closeness, barriers and motivators to participation, and perceptions of the impact of course duration and face-to-face meetings on learning. Methods: Formative evaluations were…

Guan, Jianfei; Tregonning, Sarah; Keenan, Louanne

2008-01-01

6

Formation and Properties of Magnetic Island Plasmoids in Large-Scale Current Sheets During CME Eruptions  

NASA Astrophysics Data System (ADS)

We present the continued analysis of the high-resolution 2.5D MHD simulations of sympathetic magnetic breakout eruptions from a pseudostreamer source region. We examine the generation of X- and O-type null points during the current sheet tearing and their evolution as reconnection progresses. There are three large-scale current sheets that we investigate in detail over the course of the simulation. We examine the properties of reconnection occurring within these current sheets including evolution of the current sheet lengths, Lundquist number, and reconnection rates. We also quantify the statistical and spectral properties of the fluctuations in the current sheets resulting from the resistive tearing and magnetic island plasmoid formation including the distribution of magnetic island width, flux content, and mass. We show that the temporal evolution of the spectral index of the magnetic energy density in our current sheets appears to reflect the transition from the linear to non-linear phase of the instability. Our results are in excellent agreement with recent dedicated reconnection simulations even though our current sheets’ formation, growth, and dynamics are both dictated by and in turn, govern the global evolution of sequential, sympathetic CME eruptions.

Lynch, Benjamin J.; Edmondson, Justin K

2014-06-01

7

CME Theory and Models  

NASA Astrophysics Data System (ADS)

This chapter provides an overview of current efforts in the theory and modeling of CMEs. Five key areas are discussed: (1) CME initiation; (2) CME evolution and propagation; (3) the structure of interplanetary CMEs derived from flux rope modeling; (4) CME shock formation in the inner corona; and (5) particle acceleration and transport at CME driven shocks. In the section on CME initiation three contemporary models are highlighted. Two of these focus on how energy stored in the coronal magnetic field can be released violently to drive CMEs. The third model assumes that CMEs can be directly driven by currents from below the photosphere. CMEs evolve considerably as they expand from the magnetically dominated lower corona into the advectively dominated solar wind. The section on evolution and propagation presents two approaches to the problem. One is primarily analytical and focuses on the key physical processes involved. The other is primarily numerical and illustrates the complexity of possible interactions between the CME and the ambient medium. The section on flux rope fitting reviews the accuracy and reliability of various methods. The section on shock formation considers the effect of the rapid decrease in the magnetic field and plasma density with height. Finally, in the section on particle acceleration and transport, some recent developments in the theory of diffusive particle acceleration at CME shocks are discussed. These include efforts to combine self-consistently the process of particle acceleration in the vicinity of the shock with the subsequent escape and transport of particles to distant regions.

Forbes, T. G.; Linker, J. A.; Chen, J.; Cid, C.; Kóta, J.; Lee, M. A.; Mann, G.; Miki?, Z.; Potgieter, M. S.; Schmidt, J. M.; Siscoe, G. L.; Vainio, R.; Antiochos, S. K.; Riley, P.

8

CME Theory and Models  

NASA Astrophysics Data System (ADS)

This chapter provides an overview of current efforts in the theory and modeling of CMEs. Five key areas are discussed: (1) CME initiation; (2) CME evolution and propagation; (3) the structure of interplanetary CMEs derived from flux rope modeling; (4) CME shock formation in the inner corona; and (5) particle acceleration and transport at CME driven shocks. In the section on CME initiation three contemporary models are highlighted. Two of these focus on how energy stored in the coronal magnetic field can be released violently to drive CMEs. The third model assumes that CMEs can be directly driven by currents from below the photosphere. CMEs evolve considerably as they expand from the magnetically dominated lower corona into the advectively dominated solar wind. The section on evolution and propagation presents two approaches to the problem. One is primarily analytical and focuses on the key physical processes involved. The other is primarily numerical and illustrates the complexity of possible interactions between the CME and the ambient medium. The section on flux rope fitting reviews the accuracy and reliability of various methods. The section on shock formation considers the effect of the rapid decrease in the magnetic field and plasma density with height. Finally, in the section on particle acceleration and transport, some recent developments in the theory of diffusive particle acceleration at CME shocks are discussed. These include efforts to combine self-consistently the process of particle acceleration in the vicinity of the shock with the subsequent escape and transport of particles to distant regions.

Forbes, T. G.; Linker, J. A.; Chen, J.; Cid, C.; Kóta, J.; Lee, M. A.; Mann, G.; Miki?, Z.; Potgieter, M. S.; Schmidt, J. M.; Siscoe, G. L.; Vainio, R.; Antiochos, S. K.; Riley, P.

2006-03-01

9

Global three-dimensional MHD simulation of a space weather event: CME formation, interplanetary propagation, and interaction with the magnetosphere  

NASA Astrophysics Data System (ADS)

A parallel adaptive mesh refinement (AMR) finite-volume scheme for predicting ideal MHD flows is used to simulate the initiation, structure, and evolution of a coronal mass ejection (CME) and its interaction with the magnetosphere-ionosphere system. The simulated CME is driven by a local plasma density enhancement on the solar surface with the background initial state of the corona and solar wind represented by a newly devised ``steady state'' solution. The initial solution has been constructed to provide a reasonable description of the time-averaged solar wind for conditions near solar minimum: (1) the computed magnetic field near the Sun possesses high-latitude polar coronal holes, closed magnetic field flux tubes at low latitudes, and a helmet streamer structure with a neutral line and current sheet; (2) the Archimedean spiral topology of the interplanetary magnetic field is reproduced; (3) the observed two-state nature of the solar wind is also reproduced with the simulation yielding fast and slow solar wind streams at high and low latitudes, respectively; and (4) the predicted solar wind plasma properties at 1 AU are consistent with observations. Starting with the generation of a CME at the Sun, the simulation follows the evolution of the solar wind disturbance as it evolves into a magnetic cloud and travels through interplanetary space and subsequently interacts with the terrestrial magnetosphere-ionosphere system. The density-driven CME exhibits a two-step release process, with the front of the CME rapidly accelerating following the disruption of the near-Sun closed magnetic field line structure and then moving at a nearly constant speed of ~560 km/s through interplanetary space. The CME also produces a large magnetic cloud (>100RS across) characterized by a magnetic field that smoothly rotates northward and then back again over a period of ~2 days at 1 AU. The cloud does not contain a sustained period with a strong southward component of the magnetic field, and, as a consequence, the simulated CME is somewhat ineffective in generating strong geo-magnetic activity at Earth. Nevertheless, the simulation results illustrate the potential, as well as current limitations, of the MHD-based space weather model for enhancing the understanding of coronal physics, solar wind plasma processes, magnetospheric physics, and space weather phenomena. Such models will provide the foundation for future, more comprehensive space weather prediction tools.

Groth, Clinton P. T.; De Zeeuw, Darren L.; Gombosi, Tamas I.; Powell, Kenneth G.

2000-11-01

10

CME - Coming At You  

NASA Video Gallery

An oldie but goody: The September 12, 2000 coronal mass ejection (CME), which moves directly from the sun's surface toward the viewer. This was recorded by the Solar and Heliospheric Observatory (S...

11

Getting Under a CME's Skin  

NASA Astrophysics Data System (ADS)

We present a new reconstruction technique for investigating the internal and global structure of a coronal mass ejection (CME). This technique, which we call CME Hull&Innards from Polarimetric Imaging (CHI-PI or ?–?), uses Thomson-scattered polarization measurements to locate CME structures in three-dimensional space, along with total brightness measurements to characterize the mass distribution of these structures. We apply ?–? reconstruction to the CME of 2008 December 12. Preliminary results clearly indicate sub-structure within the CME. There is also evidence for a lower-density cavity that may be associated with the CME's internal magnetic field.

de Koning, C. A.

2014-05-01

12

CME Group: Education  

NSDL National Science Digital Library

The CME Group is the world's largest futures and options exchange, and it was formed through the merger of the Chicago Mercantile Exchange, the Chicago Board of Trade, and the New York Mercantile Exchange. Everything from T-bonds to soybeans are traded as part of their daily operations, and the "Education" section of their website is a great way to learn about such matters. In this section, visitors can view featured videos created by the CME Group which cover topics like "Trading Techniques within the Gold Market" and "Energy's Role in National Security". Moving along, the "Education Resources" area includes areas with fact sheets, videos, and daily reports on "Commodities", "Energy", "Options", "Interest Rates", and ten other areas. For students of finance, economics, and business, this site will be an invaluable resource.

13

Multiwavelength CME observations  

NASA Astrophysics Data System (ADS)

We will present the results of several coordinated multi-wavelength and multi-instrument observing campaigns which produced good coverage of filament eruption related CME events. We obtained observations from spacescaft (Yohkoh, SOHO/MDI, EIT and LASCO, GOES, WIND/WAVES), as well as from ground-based observatories (THEMIS, VTT, Meudon, Mauna Loa, Nobeyama) providing magnetic, optical, EUV, X-ray and radio data. Such broad wavelength data coverage enabled us to analyze the initiation process of CMEs in the lower solar atmosphere including the filament activation process and the propagation of the CME through the upper solar atmosphere into the interplanetary space, during which we observed its interaction with other solar features. Such comprehensive observational analyzes can greatly benefit from modelling and MHD simulation studies of the observed events. We will show examples of such attempts.

Schmieder, B.; van Driel-Gesztelyi, L.; Poedts, S.

2003-04-01

14

Formation of hot channels in pre-CME coronal flux ropes and their role in the onset of eruptions  

NASA Astrophysics Data System (ADS)

Using 3D magneto-hydrodynamic simulations of the eruption of coronal flux ropes, we examine the thermal features produced by current sheet formation and the associated “tether-cutting” reconnections. We find that current sheets form along topological structures identified as quasi-separatrix layers (QSLs) during the pre-eruption stage. Tether-cutting reconnections in the current sheets produce a hot channel containing reconnected, twisted flux threading under the axis of the flux rope. This accumulation of twisted flux allows the flux rope to rise quasi-statically to the critical height for the onset of the torus instability, which leads to the dynamic eruption of the flux rope. The current sheet morphology and the hot channel that forms above it may explain the observed prominence “horns” enclosing a central cavity seen in AIA observations of coronal cavities. They may also be the cause of the X-ray emitting cores observed in some coronal cavities. We present a sequence of simulations to examine how the temperature and density of the hot channel depend on the properties of the coronal flux rope, and compare the results with multi-wavelength coronal observations of CMEs.

Fan, Yuhong; Chatterjee, P.

2013-07-01

15

CME Kinematics and Dynamics  

NASA Astrophysics Data System (ADS)

The goal of this study is to investigate the driving mechanisms of CMEs and to infer the magnetic field properties at the onset of the instability. We use EIT 195 Å images and LASCO white-light coronagraph data of a CME event that occurred on 17 December 2006. It was a long-duration event, and was associated with an occulted C2.1 class flare. To determine the driving mechanism, we quantitatively and qualitatively compared the observationally obtained kinematic evolution with that predicted by three CME models: the breakout model (BO, see Antiochos et al. 1999; Lynch et al. 2008; DeVore and Antiochos 2008), the catastrophe model (CM, see Priest and Forbes 2000), and the toroidal instability model (TI, see Chen 1989; Kliem and Török 2006). Our results indicate that this CME is best represented by the CM model. We infer that, at the onset of the instability, the Alfvén speed is approximately 120 km s-1 and the height of the flux rope is roughly 100-200Mm. These parameter values are related to the magnetic environment and the loop geometry and can be used to infer the magnetic condition at the onset of the eruption.We intend to submit the full analysis to A&A.

Lin, C.-H.; Gallagher, P. T.

16

CME Initiation and Reconnection  

NASA Technical Reports Server (NTRS)

Coronal mass ejections (CMEs) are the most massive explosions in the heliosphere, and the primary drivers of geoeffective space weather. This talk will be focused on fast CMEs, which travel at Alfvenic speeds as high as 2500 km/s. These ejections are associated with solar flares, prominence eruptions, and energetic particles accelerated near the Sun and in interplanetary space. CMEs require sufficient energy storage, in the form of magnetic stress, and rapid release of this energy. Although it is generally agreed that magnetic reconnection is the key to fast CME initiation, different models incorporate reconnection in different ways. One promising model --- the breakout scenario --- involves reconnection in two distinct yet interconnected locations: breakout reconnection ahead of the CME, and flare reconnect ion behind it. This model has been validated through 2D and 3D MHD simulations and favorable comparison with the observed properties of many fast CMEs. I will discuss what we have learned about the onset and evolution of breakout and flare reconnect ion from recent high-resolution 2D simulations of CME initiation with adaptive mesh refinement and numerical resistivity.

Karpen, Judy T.

2010-01-01

17

CME Plotting Activity  

NSDL National Science Digital Library

This is an activity about the movement of a coronal mass ejection. Learners will plot the path of two coronal mass ejections (CMEs), both the distance traveled and the increasing angular width, as they leave the Sun and travel outward through the Solar System. Then, they will sketch the path of the CMEs and identify the location on the Sun from which a CME would need to leave in order for it to hit Earth. This is the first activity in the Solar Storms and You: Exploring the Wind from the Sun educator guide.

18

The Flare/CME Connection  

NASA Technical Reports Server (NTRS)

We present evidence supporting the view that, while many flares are produced by a confined magnetic explosion that does not produce a CME, every CME is produced by an ejective magnetic explosion that also produces a flare. The evidence is that the observed heliocentric angular width of the full-blown CME plasmoid in the outer corona (at 3 to 20 solar radii) is about that predicted by the standard model for CME production, from the amount of magnetic flux covered by the co-produced flare arcade. In the standard model, sheared and twisted sigmoidal field in the core of an initially closed magnetic arcade erupts. As it erupts, tether-cutting reconnection, starting between the legs of the erupting sigmoid and continuing between the merging stretched legs of the enveloping arcade, simultaneously produces a growing flare arcade and unleashes the erupting sigmoid and arcade to become the low-beta plasmoid (magnetic bubble) that becomes the CME. The flare arcade is the downward product of the reconnection and the CME plasmoid is the upward product. The unleashed, expanding CME plasmoid is propelled into the outer corona and solar wind by its own magnetic field pushing on the surrounding field in the inner and outer corona. This tether-cutting scenario predicts that the amount of magnetic flux in the full-blown CME plasmoid nearly equals that covered by the full-grown flare arcade. This equality predicts (1) the field strength in the flare region from the ratio of the angular width of the CME in the outer corona to angular width of the full-grown flare arcade, and (2) an upper bound on the angular width of the CME in the outer corona from the total magnetic flux in the active region from which the CME explodes. We show that these predictions are fulfilled by observed CMEs. This agreement validates the standard model. The model explains (1) why most CMEs have much greater angular widths than their co-produced flares, and (2) why the radial path of a CME in the outer corona can be laterally far offset from the co-produced flare.

Moore, Ron; Falconer, David; Sterling, Alphonse

2008-01-01

19

Multi-protein delivery by nanodiamonds promotes bone formation.  

PubMed

Bone morphogenetic proteins (BMPs) are well-studied regulators of cartilage and bone development that have been Food and Drug Administration (FDA)-approved for the promotion of bone formation in certain procedures. BMPs are seeing more use in oral and maxillofacial surgeries because of recent FDA approval of InFUSE(®) for sinus augmentation and localized alveolar ridge augmentation. However, the utility of BMPs in medical and dental applications is limited by the delivery method. Currently, BMPs are delivered to the surgical site by the implantation of bulky collagen sponges. Here we evaluate the potential of detonation nanodiamonds (NDs) as a delivery vehicle for BMP-2 and basic fibroblast growth factor (bFGF). Nanodiamonds are biocompatible, 4- to 5-nm carbon nanoparticles that have previously been used to deliver a wide variety of molecules, including proteins and peptides. We find that both BMP-2 and bFGF are readily loaded onto NDs by physisorption, forming a stable colloidal solution, and are triggered to release in slightly acidic conditions. Simultaneous delivery of BMP-2 and bFGF by ND induces differentiation and proliferation in osteoblast progenitor cells. Overall, we find that NDs provide an effective injectable alternative for the delivery of BMP-2 and bFGF to promote bone formation. PMID:24045646

Moore, L; Gatica, M; Kim, H; Osawa, E; Ho, D

2013-11-01

20

Ensemble Modeling of CME Propagation  

NASA Astrophysics Data System (ADS)

The current progression toward solar maximum provides a unique opportunity to use multi-perspective spacecraft observations together with numerical models to better understand the evolution and propagation of coronal mass ejections (CMEs). Of interest to both the scientific and forecasting communities are the Earth-directed "halo" CMEs, since they typically produce the most geoeffective events. However, determining the actual initial geometries of halo CMEs is a challenge due to the plane-of-sky projection effects. Thus the recent 15 February 2011 halo CME event has been selected for this study. During this event the Solar TErrestrial RElations Observatory (STEREO) A and B spacecraft were fortuitously located ˜ 90° away from the Sun-Earth line such that the CME was viewed as a limb event from these two spacecraft, thereby providing a more reliable constraint on the initial CME geometry. These multi-perspective observations were utilized to provide a simple geometrical description that assumes a cone shape for a CME to calculate its angular width and central position. The event was simulated using the coupled Wang-Sheeley-Arge (WSA)-Enlil 3D numerical solar corona-solar wind model. Daily updated global photospheric magnetic field maps were used to drive the background solar wind. To improve our modeling techniques, the sensitivity of the modeled CME arrival times to the initial input CME geometry was assessed by creating an ensemble of numerical simulations based on multiple sets of cone parameters for this event. It was found that the accuracy of the modeled arrival times not only depends on the initial input CME geometry, but also on the accuracy of the modeled solar wind background, which is driven by the input maps of the photospheric field. To improve the modeling of the background solar wind, the recently developed data-assimilated magnetic field synoptic maps produced by the Air Force Data Assimilative Photospheric flux Transport (ADAPT) model were used. The ADAPT maps provide a more instantaneous snapshot of the global photospheric field distribution than that provided by traditional daily updated synoptic maps. Using ADAPT to drive the background solar wind, an ensemble set of eight different CME arrival times was generated, where the spread in the predictions was ˜ 13 hours and was nearly centered on the observed CME shock arrival time.

Lee, C. O.; Arge, C. N.; Odstr?il, D.; Millward, G.; Pizzo, V.; Quinn, J. M.; Henney, C. J.

2013-07-01

21

Haze activity of different barley trypsin inhibitors of the chloroform/methanol type (BTI-CMe).  

PubMed

Our previous study found that the critical protein in SE (silica eluted) proteins is BTI-CMe, and assumed that SE-ve malt for brewing may improve the haze stability in beer. In this study, we investigated the difference in gene sequence and corresponding amino acid sequence of BTI-CMe between SE+ve and SE-ve types. The results showed that there were 7 amino acid differences between Yerong (SE-ve) and Franklin (SE+ve). Two types BTI-CMe were expressed in vitro and purified successfully. By adding the purified BTI-CMe into commercial beer, we found that both original turbidity and alcohol chill haze degree of beer were increased. BTI-CMe of SE-ve haplotype showed a lower level of haze formation in beer than SE+ve haplotype. Response surface methodology (RSM) was conducted to determine the relationship between BTI-CMe and tannic acid, and their effects on haze formation. It was found that (1) higher content of BTI-CMe and/or tannic acid in beer would give rise to higher turbidity; (2) there was a significant interaction between BTI-CMe and tannic acid; (3) haze activity disparity of BTI-CMe between two types was significantly and positively correlated with the tannic acid concentration. PMID:25038664

Ye, Lingzhen; Huang, Lu; Huang, Yuqing; Wu, Dezhi; Hu, Hongliang; Li, Chengdao; Zhang, Guoping

2014-12-15

22

Solar Back-sided Halo CME  

NASA Video Gallery

The Sun erupted with several CMEs (coronal mass ejections) during a period just over a day (Nov. 8-9, 2012), the largest of which was a halo CME. This CME appears to have originated from an active ...

23

CME Autmatic Hammer Operations Bulletin.  

National Technical Information Service (NTIS)

This report is a summary of experience with the Central Mine Equipment (CME) automatic hammer is run by a hydraulic chain-cam lifting system, and the drop height of the hammer depends on the speed of the chain cam. This report addresses energy transmissio...

J. A. Farrar D. Chitwood

1999-01-01

24

Reflections on CME Congress 2012  

ERIC Educational Resources Information Center

This commentary reflects the author's impressions of Continuing Medical Education (CME) Congress 2012, a provocative international conference on professional development and quality improvement in the health professions that took place in Toronto, Ontario, last spring. The sessions he attended and conversations he had with other attendees were…

Knox, Alan B.

2013-01-01

25

Developing 3D CME Models  

NASA Astrophysics Data System (ADS)

We describe the development of CME models in three dimensions, including the energization of active regions and the initiation of eruptions via flux cancellation. We contrast the dynamics from idealized zero-beta models with more sophisticated models based on thermodynamic solutions. We explore the effect of the strength of the magnetic field in the active region (or, more appropriately, the amount of smoothing applied to the observed magnetic field), the profiles for transverse field emergence or applied shear, and the nature of the flux cancellation, on the dynamics of eruptions. In particular, our interest is in understanding which effects lead to fast CMEs.

Mikic, Zoran; Torok, Tibor; Titov, Viacheslav; Linker, Jon A.; Reeves, Kathy

2014-06-01

26

Statistical Distribution Of CME Velocity And Acceleration  

Microsoft Academic Search

We present a statistical study on the distribution of CME kinematic properties, including speed and acceleration with an emphasis on CME's dynamic evolution process in the inner corona. From 1996 to 2005, the Large Angle and Spectroscopic Coronagraph (LASCO) on SOHO spacecraft has observed about 10400 CMEs. The speed of these CMEs has a wide distribution from 20 km\\/s to

Jie Zhang

2007-01-01

27

Simvastatin-loaded ?-TCP drug delivery system induces bone formation and prevents rhabdomyolysis in OVX mice.  

PubMed

Bone formation and regeneration is a prolonged process that requires a slow drug release system to assist in the long-term recovery. A drug-delivery system is developed that allows for the controlled release of simvastin, without exhibiting the side effects associated with high concentrations of simvastatin, and is still capable of inducing constant bone formation. PMID:23184712

Chou, Joshua; Ito, Tomoko; Otsuka, Makoto; Ben-Nissan, Besim; Milthorpe, Bruce

2013-05-01

28

Recent Studies on CME-streamer Interactions  

NASA Astrophysics Data System (ADS)

Previous studies have shown the importance of streamers as a host of the CME progenitor with the magnetic energy to be released, as evidenced by observations of streamer blow-out and puff CMEs. Kinks along streamers and other coronal rays have been used to infer the dynamics of CME-driven coronal shocks. The CME-streamer interaction has also been suspected to be important for the generation of some type II radio bursts. Recent studies have discovered a new wave phenomenon dubbed as ''streamer wave', which is sometimes observed in the aftermath of CME-caused streamer deflection, and defined spectral bump and break morphological features of type II radio bursts, which are due to different transits of CME-driven shocks across a dense streamer structure. In this presentation, I will focus on these recent studies of CME-streamer interactions, and discuss how we can diagnose the coronal magnetic field strength and Alfven speed along the streamer plasma sheet with the streamer wave measurement, and infer the shock electron acceleration site as well as the shock geometry using specific features in the observed type II radio bursts. I will also discuss how a streamer-shock system forms an effective magnetic collapsing trap geometry, resulting in efficient electron acceleration to account for a special group of events termed as streamer type IIs.

CHEN, Y.

2012-12-01

29

Influence of infusion line compliance on drug delivery rate during acute line loop formation  

Microsoft Academic Search

Objective: To determine whether infusion line compliance contributes to irregular drug delivery during vertical displacement of syringe\\u000a pumps.?Design: Five different commercially available infusion lines were studied at infusion rates of 0.5, 1.0, and 1.5 ml\\/h. Zero drug\\u000a delivery time was measured after acute line loop formation (70 cm) using an electronic balance. Compliance of each infusion\\u000a line was calculated using

M. Weiss; O. Bänziger; Thomas Neff; S. Fanconi

2000-01-01

30

The abnomal increase of velocity of cme  

NASA Astrophysics Data System (ADS)

documentstyle 11pt article topmargin -2 3 cm textwidth 16 0 cm textheight 25 15 cm def baselinestretch author HAN JILING sl Beijing NormalUniversity PhysicsDepartment Beijing100875 China title The abnomal increase of velocity of cme UNDER RISING date begin document maketitle begin center bf ABSTRACT end center noindent Abstract In coronal plasma the velocity of a coronal mass ejection CME can again once be increased by accelerating of turbulence Alfven waves The change and the fluctuation of magnetic field as well as the anisotropy in ions temperature can all excite the Alfven wave turbulence The turbulence may become one-dimensional turbulence under the influence of the magnetic field of corona As the resonant condition of Alfven wave interacting with ejected particle of CME is satisfied the rising resonant particles can again once be accelerated by turbulence Alfven wave The turbulence further developing can turn into turbulence chaos And when plasma pressure parameter beta satisfies certain conditions may also form solitary kinetic Alfven wave SKAW Under similar resonant condition the resonant particles can more effectively be accelerated by SKAW The part particles acclerated will drop out its noumenon thus the distributions of the CME in velocity and mass will be changed noindent Key words CME turbulence Alfven waves again once accelerating end document

Han, Hanjl

31

Mechanism of Membranous Tunnelling Nanotube Formation in Viral Genome Delivery  

PubMed Central

In internal membrane-containing viruses, a lipid vesicle enclosed by the icosahedral capsid protects the genome. It has been postulated that this internal membrane is the genome delivery device of the virus. Viruses built with this architectural principle infect hosts in all three domains of cellular life. Here, using a combination of electron microscopy techniques, we investigate bacteriophage PRD1, the best understood model for such viruses, to unveil the mechanism behind the genome translocation across the cell envelope. To deliver its double-stranded DNA, the icosahedral protein-rich virus membrane transforms into a tubular structure protruding from one of the 12 vertices of the capsid. We suggest that this viral nanotube exits from the same vertex used for DNA packaging, which is biochemically distinct from the other 11. The tube crosses the capsid through an aperture corresponding to the loss of the peripentonal P3 major capsid protein trimers, penton protein P31 and membrane protein P16. The remodeling of the internal viral membrane is nucleated by changes in osmolarity and loss of capsid-membrane interactions as consequence of the de-capping of the vertices. This engages the polymerization of the tail tube, which is structured by membrane-associated proteins. We have observed that the proteo-lipidic tube in vivo can pierce the gram-negative bacterial cell envelope allowing the viral genome to be shuttled to the host cell. The internal diameter of the tube allows one double-stranded DNA chain to be translocated. We conclude that the assembly principles of the viral tunneling nanotube take advantage of proteo-lipid interactions that confer to the tail tube elastic, mechanical and functional properties employed also in other protein-membrane systems.

Peralta, Bibiana; Gil-Carton, David; Castano-Diez, Daniel; Bertin, Aurelie; Boulogne, Claire; Oksanen, Hanna M.; Bamford, Dennis H.; Abrescia, Nicola G. A.

2013-01-01

32

Automatic CME Detection from Coronagraph Image Pairs  

NASA Astrophysics Data System (ADS)

We have developed a technique for the automatic detection of coronal mass ejections using two sequential coronagraph images. The technique is based on tracking arc-like features from one image to the next; the feature's velocity is also determined. The method has been developed and tested using LASCO C2 and C3 data. The goal of this work is to develop an automatic CME detection algorithm that can be used on board the STEREO spacecraft to preferentially downlink data containing CMEs from an onboard "rotating" data buffer. Results for this detection technique compare very favorably with CMEs identified in the LASCO CME catalog (http://cdaw.gsfc.nasa.gov/CME_list/). For the periods when results were compared, no time periods with significant CMEs were missed using the automatic technique.

Liewer, P. C.; Dejong, E. M.; Hall, J. R.; Lorre, J. J.

2005-12-01

33

Parenting Interventions Implementation Science: How Delivery Format Impacts the Parenting Wisely Program  

ERIC Educational Resources Information Center

Objectives: This study examines the implementation and effectiveness of Parenting Wisely, an Internet-based parenting skills intervention. The study assesses whether parents benefit from Parenting Wisely participation and whether the delivery format influences program effectiveness. Method: This study uses a quasi-experimental design.…

Cotter, Katie L.; Bacallao, Martica; Smokowski, Paul R.; Robertson, Caroline I. B.

2013-01-01

34

CME Flux ropes: Origins, Characteristics and Consequences  

NASA Astrophysics Data System (ADS)

A CME flux rope is a magnetic structure propelled from the Sun during a solar eruption, which often includes a solar flare, a prominence disruption and the CME. CME flux ropes begin at the low corona over the polarity inversion lines (PILs) of the photospheric radial magnetic field. Solar eruptions have been explained as the loss of equilibrium of flux ropes held down by the coronal field. The flux ropes may be emerged from the solar interior or gradually formed in the low corona. Alternatively, the CME flux ropes form during the eruptions by magnetic reconnection under the sheared coronal arcades over the PILs. The source regions of CMEs can be large sunspot active regions with kilogauss magnetic field, quiescent prominences in decayed magnetic field and coronal streamers over the quiet Sun. After the initiation of the eruption, the CME flux ropes undergo acceleration (deceleration), expansion, rotation, distortion and interaction with the ambient solar wind during the propagation in the heliosphere. The internal plasma and magnetic field of the CME flux ropes are measured when the structure encounters a spacecraft in the solar wind. The interplanetary CMEs (ICMEs) at 1AU have radial dimension ranging 0.1 to 0.5 AU, speed ranging 300 to 1000 km/s, and internal magnetic field ranging 10 to 50 nT. A significant fraction of ICMEs are flux rope type or magnetic clouds (MCs), the field of which are quite consistent with the field produced by a cylindrical flux rope with various orientations. Most MCs produce out-of ecliptic plane magnetic field. When the MCs contain both northward and southward field, they are bipolar MCs. The polarity of the bipolar MCs has been found to have a solar cycle dependence and follows the solar dipole field. MCs containing extended strong southward field cause the most intense geomagnetic disturbances.

Li, Y.; Luhmann, J. G.; Lynch, B. J.; Kilpua, E.

2011-12-01

35

A CME approach to smoking cessation.  

PubMed

Overall, both project participants and project coordinators were very positive about their experiences and the outcomes of the projects. Several projects went beyond expectations, utilizing patient audits to determine outcomes and indicated changes in processes and behaviors to improve patient outcomes in smoking cessation. Many grantees indicated that their project was a catalyst for future programs and other policy changes. Finally, local CME coordinators acknowledged that this type of project with supporting evaluation and content assisted them in providing higher quality CME and meeting the new Accreditation Council for Continuing Medical Education requirements. PMID:21319662

Addleton, Robert L; Cohen, Adele B

2010-01-01

36

Space Weather Model of July 22-23, 2012 CME  

NASA Video Gallery

NASA's Space Weather Research Center modeled the July 23, 2012 CME using a modeling program called ENLIL. The CME can be seen to expand dramatically as it travels through space. By comparing how we...

37

Deflected Propagation ---- A Factor Deciding the Geoeffectiveness of A CME  

Microsoft Academic Search

To answer the question if a CME can cause a significant change of the states of geo-space, the first issue we have to address is whether or not the CME will intersect with the Earth or what the trajectory of the CME is. From several observational cases and statistical studies, we show that the deflected propagations of CMEs are a

Y. Wang; C. Shen; J. Liu; B. Gui; S. Wang

2010-01-01

38

Assessment of Barriers to Changing Practice as CME Outcomes  

ERIC Educational Resources Information Center

Introduction: Continuing medical education (CME) is meant to drive and support improvements in practice. To achieve this goal, CME activities must move beyond simply purveying knowledge, instead helping attendees to contextualize information and to develop strategies for implementing new learning. CME attendees face different barriers to…

Price, David W.; Miller, Elaine K.; Rahm, Alanna Kulchak; Brace, Nancy E.; Larson, R. Sam

2010-01-01

39

CME and Change in Practice: An Alternative Perspective.  

ERIC Educational Resources Information Center

Results of a study by the American College of Cardiology revealed that continuing medical education (CME) courses contain relatively little information that is new to the audience, that other influences on practice interact with CME content, and that change attributable to CME is subtle and often delayed. (JOW)

Wergin, Jon F.; And Others

1988-01-01

40

Learning to Collaborate: A Case Study of Performance Improvement CME  

ERIC Educational Resources Information Center

Introduction: Performance Improvement Continuing Medical Education (PI CME) is a mechanism for joining quality improvement (QI) in health care to continuing medical education (CME) systems together. Although QI practices and CME approaches have been recognized for years, what emerges from their integration is largely unfamiliar, because it…

Shershneva, Marianna B.; Mullikin, Elizabeth A.; Loose, Anne-Sophie; Olson, Curtis A.

2008-01-01

41

The CME Flare Arcade and the Width of the CME in the Outer Corona  

NASA Technical Reports Server (NTRS)

Moore, Sterling, & Suess (2007, ApJ, 668, 1221) present evidence that (1) a CME is typically a magnetic bubble, a low-beta gplasmoid with legs h having roughly the 3D shape of a light bulb, and (2) in the outer corona the CME plasmoid is in lateral pressure equilibrium with the ambient magnetic field. They present three CMEs observed by SOHO/LASCO, each from a very different source located near the limb. One of these CMEs came from a compact ejective eruption from a small part of a sunspot active region, another came from a large quiet-region filament eruption, and the third CME, an extremely large and fast one, was produced in tandem with an X20 flare arcade that was centered on a huge delta sunspot. Each of these CMEs had more or less the classic lightbulb silhouette and attained a constant heliocentric angular width in the outer corona. This indicates that the CME plasmoid attained lateral magnetic pressure balance with the ambient radial magnetic field in the outer corona. This lateral pressure balance, together with the standard scenario for CME production by the eruption of a sheared-core magnetic arcade, yields the following simple estimate of the strength B(sub Flare) of the magnetic field in the flare arcade produced together with the CME: B(sub Flare) 1.4(theta CME/theta Flare)sup 2 G, where theta (sub CME) is the heliocentric angular width of the CME plasmoid in the outer corona and theta (sub Flare) is the heliocentric angular width of the full-grown flare arcade. Conversely, theta (sub CME) approximately equal to (R(sub Sun)sup -1(phi(sub Flare)/1.4)sup 1/2 radians, where Flare is the magnetic flux covered by the full-grown flare arcade. In addition to presenting the three CMEs of Moore, Sterling, & Suess (2007) and their agreement with this relation between CME and Flare, we present a further empirical test of this relation. For CMEs that erupt from active regions, the co-produced flare arcade seldom if ever covers the entire active region: if AR is the total magnetic flux of the active region, Flare . AR, and we predict that CME. (R(sub Sun))sup -1(theta AR/1.4)sup 1/2 radians. For a random sample of 31 CMEs that erupted from active regions within 30 of the limb, for each CME we have measured CME from LASCO/C3 and have measured AR from a SOHO/MDI magnetogram of the source active region when it was within 30 of disk center. We find that each CME obeys the above predicted inequality, none having width greater than half of the upper bound given by theta(sub AR). Thus, an active region's magnetic flux content, together with its location on the solar disk, largely determines whether the active region can possibly produce a CME that is wide enough to intercept the Earth.

Moore, Ron; Falconer, David; Sterling, Alphonse

2008-01-01

42

CHARACTERISTICS OF KINEMATICS OF A CORONAL MASS EJECTION DURING THE 2010 AUGUST 1 CME-CME INTERACTION EVENT  

SciTech Connect

We study the interaction of two successive coronal mass ejections (CMEs) during the 2010 August 1 events using STEREO/SECCHI COR and heliospheric imager (HI) data. We obtain the direction of motion for both CMEs by applying several independent reconstruction methods and find that the CMEs head in similar directions. This provides evidence that a full interaction takes place between the two CMEs that can be observed in the HI1 field of view. The full de-projected kinematics of the faster CME from Sun to Earth is derived by combining remote observations with in situ measurements of the CME at 1 AU. The speed profile of the faster CME (CME2; {approx}1200 km s{sup -1}) shows a strong deceleration over the distance range at which it reaches the slower, preceding CME (CME1; {approx}700 km s{sup -1}). By applying a drag-based model we are able to reproduce the kinematical profile of CME2, suggesting that CME1 represents a magnetohydrodynamic obstacle for CME2 and that, after the interaction, the merged entity propagates as a single structure in an ambient flow of speed and density typical for quiet solar wind conditions. Observational facts show that magnetic forces may contribute to the enhanced deceleration of CME2. We speculate that the increase in magnetic tension and pressure, when CME2 bends and compresses the magnetic field lines of CME1, increases the efficiency of drag.

Temmer, Manuela; Rollett, Tanja; Bein, Bianca; Moestl, Christian; Veronig, Astrid M.; Flor, Olga [Kanzelhoehe Observatory-IGAM, Institute of Physics, University of Graz, Universitaetsplatz 5, A-8010 Graz (Austria); Vrsnak, Bojan; Zic, Tomislav [Hvar Observatory, Faculty of Geodesy, University of Zagreb, Kaciceva 26, HR-10000 Zagreb (Croatia); De Koning, Curt A. [NOAA Space Weather Prediction Center, Boulder, CO 80305 (United States); Liu, Ying [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Bosman, Eckhard [Space Research Institute, Austrian Academy of Sciences, A-8042 Graz (Austria); Davies, Jackie A.; Bothmer, Volker [Institut fuer Astrophysik, Goettingen University, Friedrich-Hund Platz 1, D-37077 Goettingen (Germany); Harrison, Richard [RAL Space, Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX (United Kingdom); Nitta, Nariaki [Solar and Astrophysics Laboratory, Lockheed Martin Advanced Technology Centre, Palo Alto, CA 94304-1191 (United States); Bisi, Mario [Institute of Mathematics and Physics, Aberystwyth University, Ceredigion SY23 3BZ (United Kingdom); Eastwood, Jonathan; Forsyth, Robert [The Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom); Odstrcil, Dusan, E-mail: mat@igam.uni-graz.at [Computational and Data Sciences, George Mason University/NASA Goddard Space Flight Center, Mail Code 674, Greenbelt, MD 20771 (United States)

2012-04-10

43

A Challenging Solar Eruptive Event of 18 November 2003 and the Causes of the 20 November Geomagnetic Superstorm. III. Catastrophe of the Eruptive Filament at a Magnetic Null Point and Formation of an Opposite-Handedness CME  

NASA Astrophysics Data System (ADS)

Our analysis in Papers I and II (Grechnev et al., Solar Phys. 289, 289, 2014b and Solar Phys. 289, 1279, 2014c) of the 18 November 2003 solar event responsible for the 20 November geomagnetic superstorm has revealed a complex chain of eruptions. In particular, the eruptive filament encountered a topological discontinuity located near the solar disk center at a height of about 100 Mm, bifurcated, and transformed into a large cloud, which did not leave the Sun. Concurrently, an additional CME presumably erupted close to the bifurcation region. The conjectures about the responsibility of this compact CME for the superstorm and its disconnection from the Sun are confirmed in Paper IV (Grechnev et al., Solar Phys. submitted, 2014a), which concludes about its probable spheromak-like structure. The present article confirms the presence of a magnetic null point near the bifurcation region and addresses the origin of the magnetic helicity of the interplanetary magnetic clouds and their connection to the Sun. We find that the orientation of a magnetic dipole constituted by dimmed regions with the opposite magnetic polarities away from the parent active region corresponded to the direction of the axial field in the magnetic cloud, while the pre-eruptive filament mismatched it. To combine all of the listed findings, we propose an intrinsically three-dimensional scheme, in which a spheromak-like eruption originates via the interaction of the initially unconnected magnetic fluxes of the eruptive filament and pre-existing ones in the corona. Through a chain of magnetic reconnections their positive mutual helicity was transformed into the self-helicity of the spheromak-like magnetic cloud.

Uralov, A. M.; Grechnev, V. V.; Rudenko, G. V.; Myshyakov, I. I.; Chertok, I. M.; Filippov, B. P.; Slemzin, V. A.

2014-04-01

44

Plasmoid instability in a large post-CME current sheet system  

NASA Astrophysics Data System (ADS)

Solar flares and CME that cause violent space weather change have been studied for years. The standard model suggests that there is a current sheet connecting the CME and the site of the post-CME flare after the eruption, but understanding of the detailed physical mechanism of dynamical processes in the current sheet remains incomplete. Recently, the secondary plasmoid instabilities of large scale current sheet in high Lundquist number environment such as solar corona and the change of magnetic topology in such a current sheet system has become a subject of great interest (Bhattacharjee et al. 2009). In our work, we study a post-CME current sheet via both observation and simulation. We use SOHO/LASCO observations of a fast halo CME as well as a slow CME. After the fast halo CME event on January 8, 2002, we observe a long, thin current sheet which connects the CME to a flare site on the surface of the sun. In this current sheet we identify over 60 bright plasmoid-like blobs in 39 hours. In the slow CME event on June 25, 2005, we observe 32 such blobs in 18 hours after the formation of the current sheet. We simulate both cases using high-Lundquist-number resistive MHD simulations of the model of Lin & Forbes (2000), and demonstrate that the distribution of plasmoid size in both cases appears to conform well to a distribution function that is independent of the Lundquist number and predicted by theory. The average observed plasmoid speed in both cases is a fraction of the typical Alfven speed, qualitatively consistent with the simulations. Thus, we propose that these observations can be plausibly accounted for by the plasmoid instability of the large-scale current sheet. The observed bright blobs are probably evidence of large-scale plasmoids, and their behavior appears to be qualitatively consistent with high-Lundquist-number MHD simulations.
observation case summary

Guo, L.; Bhattacharjee, A.; Huang, Y.; Center for Integrated Computation; Analysis of Reconnection; Turbulence

2011-12-01

45

Radio signatures of CME-streamer interaction  

NASA Astrophysics Data System (ADS)

Recent observational finding of streamer waves using the LASCO white light data presents us interesting physical consequence of CME-streamer interactions [1, 2, 3]. CME-streamer interactions can also manifest themselves in the Type-II-related radio dynamic spectra as recorded by the ground-based or space-borne instruments. A large body of studies exists revealing the possible roles of pre-existing helmet streamers in the radio emission during a solar eruption. In this presentation, we will summary our efforts in classifying the roles of streamers affecting Type-II radio emissions. Generally speaking, there exist two groups of CME-streamer-Type-II events. In the first group, the shock as well as the Type-II radio emission seems to exist prior to the CME-streamer interaction. The interaction can be clearly discerned from the well-defined bump of the Type-II radio dynamic spectra. The spectral bump is a direct result of plasma emissions when the radio emitting region traversing the denser streamer structure. In the other group of events, the Type-II burst is excited as a result of the CME-streamer interaction. Either the shock is formed and radio-emitting electrons are accelerated inside the streamer, or a prior non-emitting shock becomes radio aloud during the interacting process. A novel triangular-streamer-shock model is proposed to interpret the associated electron acceleration inside the streamer. Observational examples of CME-streamer-radio events corresponding to both cases will be presented. [1] Chen, Y., Song, H.Q., Li, B., Xia, L.D., Wu, Z., Fu, H., Li, X., 2010, Astrophys. J. 714, 644 [2] Chen, Y., Feng, S.W., Li, B., Song, H.Q., Xia, L.D., Kong, X.L., Li, X., 2011, Astrophys. J. 728, 147 [3] Feng S. W., Chen Y., Li B., Song H. Q., Kong X. L., Xia L. D., Feng, X. S., 2011, Sol. Phys., DOI 10.1007/s11207-011-9814-6

CHEN, Y.; Feng, S.; Kong, X.; Li, G.; Song, H.

2011-12-01

46

Understand CME Structures Near the Earth  

NASA Astrophysics Data System (ADS)

The geoeffectiveness of an interplanetary coronal mass ejection ICME) mainly depends on the length and/or duration of the presence of southward magnetic fields in its structure. The structure has two essential components, one the ICME ejecta itself , and the other the preceding sheath region often bounded by a shock in the front. We investigate the evolution process of a CME in the interplanetary space that leads to the geometric structure observed in the near-Earth space. We examine several CME-ICME events that are well tracked continuously from the Sun to the Earth by the twin STEREO spacecraft and in-situ instruments. We study the evolution of shock fronts and ICME fronts, thus the size of sheath regions. We also determine the bulk velocity and the expansion velocity of the ICMEs, thus their size evolution. This study will help us accurately predict the arrival time of ICMEs, and their potential geoeffectiveness as well.

Zhang, Jie; Hess, . Phillip

2012-07-01

47

Formation mechanism of the pressure zone at the tip of the melt delivery tube during the spray forming process  

Microsoft Academic Search

The gas pressures at the tip of the melt delivery tube in two typical atomizers are measured in this work. Gas dynamics is used to study the gas flow and pressure zone at the tip of the delivery tube, and a mechanism for the formation of pressurization and aspiration is proposed. The results show that the atomization efficiency of an

Chengsong Cui; Fuyang Cao; Qingchun Li

2003-01-01

48

Ly-alpha and white light observations of a CME during the Spartan 201-1 mission  

NASA Technical Reports Server (NTRS)

A coronal mass ejection (CME) near a large active region on the west limb was observed with the white light coronograph (WLC) and ultraviolet coronal spectrometer (UVCS) on the Spartan 201 satellite at 9:42 UT on 12 Apr. 1993. Soft X-ray images of the region below the CME were obtained out to 1.7 solar radii with the soft X-ray telescope (SXT) on Yohkoh. After the event, the formation of a new helmet streamer could be seen in the polarized brightness (pB) images from the Mk III coronograph at Mauna Loa. The CME was observed from Spartan 201 in two different pB images obtained 14 min apart using the WLC, and was observed moving through the field-of-view of the UVCS integrated intensity slit. Ly-alpha intensities in the same region of the corona were obtained one orbit earlier (prior to the CME) using the Ly-alpha profile slit of the UVCS. These are the first Ly-alpha observations of a CME and may help constrain models of the electron temperature on CME's.

Hassler, Don M.; Strachan, Leonard; Gardner, L. D.; Kohl, J. L.; Guhathakurta, Madhulika; Fisher, Richard R.; Strong, K.

1994-01-01

49

Desktop document delivery using portable document format (PDF) files and the Web.  

PubMed

Desktop access to electronic full-text literature was rated one of the most desirable services in a client survey conducted by the University of Washington Libraries. The University of Washington Health Sciences Libraries (UW HSL) conducted a ten-month pilot test from August 1996 to May 1997 to determine the feasibility of delivering electronic journal articles via the Internet to remote faculty. Articles were scanned into Adobe Acrobat Portable Document Format (PDF) files and delivered to individuals using Multipurpose Internet Mail Extensions (MIME) standard e-mail attachments and the Web. Participants retrieved scanned articles and used the Adobe Acrobat Reader software to view and print files. The pilot test required a special programming effort to automate the client notification and file deletion processes. Test participants were satisfied with the pilot test despite some technical difficulties. Desktop delivery is now offered as a routine delivery method from the UW HSL. PMID:9681165

Shipman, J P; Gembala, W L; Reeder, J M; Zick, B A; Rainwater, M J

1998-07-01

50

A statistical comparison of interplanetary shock and CME propagation models  

Microsoft Academic Search

We have compared the prediction capability of two types of Sun-Earth connection models: (1) ensemble of physics-based shock propagation models (STOA, STOA-2, ISPM, and HAFv.2) and (2) empirical CME propagation (CME-ICME and CME-IP shock) models. For this purpose, we have selected 38 near-simultaneous pairs of coronal mass ejections (CMEs) and metric type II radio bursts. By applying the adopted models

K.-S. Cho; Y.-J. Moon; M. Dryer; C. D. Fry; Y.-D. Park; K.-S. Kim

2003-01-01

51

CME-CME Interaction As Revealed by MHD Simulations and SECCHI Observations  

NASA Astrophysics Data System (ADS)

As we move towards solar maximum 24, immense progress can be expected in the forecasting and understanding of space weather and solar eruptions, thanks to the expanding fleet of satellites observing the Sun and the heliosphere (SOHO, Hinode, STEREO, SDO). As the frequency of coronal mass ejections (CMEs) increases to multiple eruptions per day, the interaction of successive CMEs in the inner heliosphere becomes more likely. CME-CME interaction is thought to be one major cause of intense and extreme geo-magnetic storms due to the compression of the magnetic field and the extended duration. In this talk, I will discuss how magneto-hydrodynamics (MHD) models and remote-sensing observations can shed light on the physical processes during CME-CME interaction and help explain complex in situ measurements at 1 AU. I will present some recent remote-sensing observations by STEREO/SECCHI of CMEs interacting in the heliosphere and discuss how knowledge gained from past numerical and observational studies may help us predict geo-effective events associated with multiple CMEs from remote-sensing observations.

Lugaz, Noé; Farrugia, Charles; Roussev, Ilia; Moestl, Christian; Davies, Jackie; Gombosi, Tamas

2012-07-01

52

A new interactive approach to Continuous Medical Education (CME) Journal CME  

PubMed Central

This article introduces the new Continuing Medical Education (CME) section of the interactive Journal of Radiology Case Reports. This section provides SA-CMEs which are a new requirement for Maintenance of Certification (MOC) by the American Board of Radiology (ABR) and other medical specialties.

Talanow, Roland

2014-01-01

53

pH-Sensitive Tubular Polymersomes: Formation and Applications in Cellular Delivery.  

PubMed

Optimizing the shape of a nanovector influences its interaction with a cell and determines the internalization kinetics. Block copolymer amphiphiles self-assemble into monodisperse structures in aqueous solutions and have been explored extensively as drug delivery vectors. However, the structure of self-assembled block copolymers has mainly been limited to spherical vesicles or spherical and worm-like micelles. Here we show the controlled formation and purification of tubular polymersomes, long cylindrical vesicles. Tubular polymersomes are purified from other structures, and their formation is manipulated by incorporating the biocompatible membrane components cholesterol and phospholipids. Finally we show that these tubular polymersomes have different cellular internalization kinetics compared with spherical polymersomes and can successfully encapsulate and deliver fluorescent bovine serum albumin protein intracellularly. PMID:24724711

Robertson, James D; Yealland, Guy; Avila-Olias, Milagros; Chierico, Luca; Bandmann, Oliver; Renshaw, Stephen A; Battaglia, Giuseppe

2014-05-27

54

Three-Dimensional Structure of Flux-Rope CME's: Theory and Observation  

Microsoft Academic Search

A recent program of direct comparison of model CME results and CME observations [1-4] has produced a coherent view of the geometry and the dynamics of a specific class of CME's, which we refer to as ``flux-rope CME's.'' We further support this view by presenting LASCO\\/EIT measurements and model results for 11 flux-rope CME events. Each CME is compared to

J. Krall; J. Chen; R. A. Howard; B. J. Thompson

2000-01-01

55

CME Earthward Direction as an Important Geoeffectiveness Indicator  

Microsoft Academic Search

Frontside halo coronal mass ejections (CMEs) are generally considered as potential candidates for producing geomagnetic storms, but there was no definite way to predict whether they will hit the Earth or not. Recently Moon et al. suggested that the degree of CME asymmetries, as defined by the ratio of the shortest to the longest distances of the CME front measured

R.-S. Kim; K.-S. Cho; K.-H. Kim; Y.-D. Park; Y.-J. Moon; Y. Yi; J. Lee; H. Wang; H. Song; M. Dryer

2008-01-01

56

Toward an empirical model of the CME-storm relationship  

Microsoft Academic Search

Solar and Space Weather group in KASI has been examining the physcial characteristics of geoeffective CMEs in order to develop an empirical model of the CME-storm relationship First we have presented the probablities of CME geoeffectiveness depending its solar surface location speed and earthward direction using front-side SOHO LASCO halo CMEs from 1997 to 2003 Second we have examined the

Y.-J. Moon; K.-S. Cho; R.-S. Kim; S.-M. Kang; Y.-H. Kim; K.-H. Kim; S.-C. Bong; Y. D. Park

2006-01-01

57

CME masses measured by the HELIOS spacecraft photometers  

NASA Technical Reports Server (NTRS)

We have cataloged 160 CMEs detected in the HELIOS 1 and 2 90 deg zodiacal light photometers observed from 1975-1985. The HELIOS 1 and 2 spacecraft orbited from 0.3 to 1.0 AU on 6-month orbits. From the photometer observations of Thomson-scattered light in the inner heliosphere, we have determined CME masses for these events using two methods: (1) by integration over the contours drawn between the three photometers at a given time; and (2) by integration of the mass flow over time past a given photometer. The second method, not readily available using coronagraph observations, is derived from CME speeds measured by using the timing of the peak CME brightness from the 16 deg to 31 deg sets of photometers. The two different HELIOS methods of determining CME mass are consistent with one another for individual CMEs. We find that the CME mass values range from 10(exp 15)g to nearly 10(exp 17)g. We compare the mass distributions of HELIOS-measured CMEs with those from coronagraphs and find that CMEs measured by HELIOS over the same time interval are generally more massive. The solar cycle variation of the total CME mass present in the heliosphere varies by over a factor of approximately 15 from solar minimum to solar maximum. Slightly more massive CMEs carry the bulk of the CME mass during maximum. The total CME mass at solar maximum is found to be near 15% of the total solar wind mass.

Jackson, B. V.; Webb, D. F.

1995-01-01

58

Improved Cardiovascular Prevention Using Best CME Practices: A Randomized Trial  

ERIC Educational Resources Information Center

Introduction: It was hypothesized that after a continuing medical education (CME) event, practice enablers and reinforcers addressing main clinical barriers to preventive care would be more effective in improving general practitioners' (GPs) adherence to cardiovascular guidelines than a CME event only. Methods: A cluster-randomized trial was…

Laprise, Rejean; Thivierge, Robert; Gosselin, Gilbert; Bujas-Bobanovic, Maja; Vandal, Sylvie; Paquette, Daniel; Luneau, Micheline; Julien, Pierre; Goulet, Serge; Desaulniers, Jean; Maltais, Paule

2009-01-01

59

Acceleration of Fast CME: A Parametric Study  

NASA Astrophysics Data System (ADS)

The analysis of LASCO/SOHO, Skylab and Solar Maximum Mission (SMM) observations show that there are many CMEs initiated with streamer and flux-rope magnetic topology (Dere et al. 1999; St. Cyr et al., 1999; Plunkett et al., 2000). Two types of CMEs have been distinguished with different kinematic characteristics (MacQueen and Fisher, 1983; Andrews and Howard, 2001). These are fast CMEs with high initial speeds (i.e. constant speed) and slow CMEs with low initial speeds but gradual acceleration (i.e. accelerated CMEs). Efforts have been made to probe the underlying physics responsible for these dual characteristics. Low and Zhang (2002) proposed that fast and slow CMEs result from initial topology of the magnetic field characterized by normal and inverse quiescent prominences, respectively. Liu et al. have successfully performed a numerical MHD simulation for this scenario. In this presentation, we explore other possible processes using a 2.5D, time-dependent streamer and flux-rope MHD model (Wu and Guo, 1997) to investigate the dual kinematic properties of the CMEs by specifying the different initiation processes with a particular magnetic topology (i.e. inverse quiescent prominence magnetic topology). Two typical initiation processes are tested; (1) injection of the magnetic flux into the flux-rope causes additional Lorentz force to destabilize the streamer launching a CME (Wu et al., 1997) resulting in a category slow CME and (2) draining the plasma from the flux-rope together with flux injection leads to a balloon instability due to the magnetic buoyancy force which results in a impulsive eruption and launches a fast CME. References Andrews, M.D. and Howard, R.A., Space Sci. Rev., 95, 147, 2001 Dere, K.P. et al., Ap. J., 529, 575, 1999 Lin, et al., Proceedings of ICSC 2003: Solar Variability as an Input to the Earth's Environemnt, ESA-SP-535, 2003 (in press). Low, B.C. and Zhang, M., Ap. J., 564, L53, 2002. MacQueen, R.M. and Fisher, R.R., Solar Phys. 89, 89, 1983. Plunket, S., et al., Solar Phys. 194, 321, 2000. St. Cry., O.C. et al., J. Geophys. Res., 104, 12493, 1999. Wu, S.T. and Guo, W.P. in Coronal Mass Ejection, Geophys. Monogr. Ser. 99, (N. Crooker, et al. eds.), AGU Washington, DC 1997. Wu, S.T. et al., Solar Phys., 175, 719, 1997.

Wu, S. T.; Zhang, T. X.; Tan, A.

2003-12-01

60

Plasma Radiation and Acceleration Effectiveness of CME-driven Shocks  

NASA Astrophysics Data System (ADS)

CME-driven shocks are effective radio radiation generators and accelerators for Solar Energetic Particles (SEPs). We present simulated 3 D time-dependent radio maps of second order plasma radiation generated by CME- driven shocks. The CME with its shock is simulated with the 3 D BATS-R-US CME model developed at the University of Michigan. The radiation is simulated using a kinetic plasma model that includes shock drift acceleration of electrons and stochastic growth theory of Langmuir waves. We find that in a realistic 3 D environment of magnetic field and solar wind outflow of the Sun the CME-driven shock shows a detailed spatial structure of the density, which is responsible for the fine structure of type II radio bursts. We also show realistic 3 D reconstructions of the magnetic cloud field of the CME, which is accelerated outward by magnetic buoyancy forces in the diverging magnetic field of the Sun. The CME-driven shock is reconstructed by tomography using the maximum jump in the gradient of the entropy. In the vicinity of the shock we determine the Alfven speed of the plasma. This speed profile controls how steep the shock can grow and how stable the shock remains while propagating away from the Sun. Only a steep shock can provide for an effective particle acceleration.

Gopalswamy, N.; Schmidt, J. M.

2008-05-01

61

Plasma radiation and acceleration effectiveness of CME-driven shocks  

NASA Astrophysics Data System (ADS)

CME-driven shocks are effective radio radiation generators and accelerators for Solar Energetic Particles (SEPs). We present simulated 3 D time-dependent radio maps of second order plasma radiation generated by CME-driven shocks. The CME with its shock is simulated with the 3 D BATS-R-US CME model developed at the University of Michigan. The radiation is simulated using a kinetic plasma model that includes shock drift acceleration of electrons and stochastic growth theory of Langmuir waves. We find that in a realistic 3 D environment of magnetic field and solar wind outflow of the Sun the CME-driven shock shows a detailed spatial structure of the density, which is responsible for the fine structure of type II radio bursts. We also show realistic 3 D reconstructions of the magnetic cloud field of the CME, which is accelerated outward by magnetic buoyancy forces in the diverging magnetic field of the Sun. The CME-driven shock is reconstructed by tomography using the maximum jump in the gradient of the entropy. In the vicinity of the shock we determine the Alfven speed of the plasma. This speed profile controls how steep the shock can grow and how stable the shock remains while propagating away from the Sun. Only a steep shock can provide for an effective particle acceleration.

Schmidt, Joachim

62

CME Interaction with Large-Scale Coronal Structures  

NASA Technical Reports Server (NTRS)

This talk presents some key observations that highlight the importance of CME interaction with other large scale structures such as CMEs and coronal holes . Such interactions depend on the phase of the solar cycle: during maximum, CMEs are ejected more frequently, so CME-CME interaction becomes dominant. During the rise phase, the polar coronal holes are strong, so the interaction between polar coronal holes and CMEs is important, which also leads to a possible increase in the number of interplanetary CMEs observed as magnetic clouds. During the declining phase, there are more equatorial coronal holes, so CMEs originating near these coronal holes are easily deflected. CMEs can be deflected toward and away from the Sun-Earth line resulting in interesting geospace consequences. For example, the largest geomagnetic storm of solar cycle 23 was due to a CME that was deflected towards the Sun-earth line from E22. CME deflection away from the Sun-Earth line diminishes the chance of a CME producing a geomagnetic storm. CME interaction in the coronagraphic field of view was first identified using enhanced radio emission, which is an indication of acceleration of low energy (approx.10 keV) electrons in the interaction site. CME interaction, therefore, may also have implications for proton acceleration. For example, solar energetic particle events typically occur with a higher intensity, whenever multiple CMEs occur in quick succession from the same source region. CME deflection may also have implications to the arrival of energetic particles to earth because magnetic connectivity may be changed by the interaction. I illustrate the above points using examples from SOHO, STEREO, Wind, and ACE data .

Gopalswarny, Nat

2012-01-01

63

Small-Angle Neutron Scattering and Spontaneous Formation of Unilamellar Vesicles: Potential Vehicles for Drug Delivery  

NASA Astrophysics Data System (ADS)

Unilamellar vesicles (ULVs) are single-bilayer shells with radii commonly between 10 and 100 nm, and are widely used as model membranes, drug delivery systems, microreactors and substrates for a variety of enzymes and proteins. A common method of making ULVs is the extrusion of multilamellar vesicles (MLVs) through synthetic membranes of known pore size. These extruded ULVs are invariably unstable and in due time, revert back to MLVs. Over the years there have been reports of the spontaneous formation of stable ULVs in surfactant, lipid, and lipid/detergent mixtures. These ULVs have sometimes been shown to be monodisperse and their radii were found, almost without exception, to vary with concentration. We have carried-out small-angle neutron scattering (SANS) experiments on a biomimetic system composed of the phospholipids dimyristoyl and dihexanoyl phosphorylcholine (DMPC and DHPC, respectively). Doping DMPC/DHPC multilamellar vesicles with either the negatively charged lipid dimyristoyl phosphorylglycerol (DMPG, net charge -1) or the divalent cation, calcium (Ca2+) leads to the spontaneous formation of monodisperse unilamellar vesicles whose radii are concentration independent, in contrast to previous experimental observations.

Katsaras, John

2004-03-01

64

The interplay of phase inversion and membrane formation in the drug release characteristics of a membrane-based delivery system  

Microsoft Academic Search

The interplay of phase inversion and membrane formation in the drug release characteristics of a cellulose acetate (CA) membrane-based delivery system has been examined. Drug encapsulated films were cast from solutions of naproxen (drug), CA (polymer), acetone (solvent), and water (nonsolvent). Membrane morphologies, drug release kinetics, and drug–polymer interactions were studied using scanning electron microscopy (SEM), USP apparatus 5 dissolution

Decheng Ma; Anthony J. McHugh

2007-01-01

65

Evaluation of a Thiolated Chitosan Scaffold for Local Delivery of BMP-2 for Osteogenic Differentiation and Ectopic Bone Formation  

PubMed Central

Thiolated chitosan (Thio-CS) is a well-established pharmaceutical excipient for drug delivery. However, its use as a scaffold for bone formation has not been investigated. The aim of this study was to evaluate the potential of Thio-CS in bone morphogenetic protein-2 (BMP-2) delivery and bone formation. In vitro study showed that BMP-2 interacted with the Thio-CS and did not affect the swelling behavior. The release kinetics of BMP-2 from the Thio-CS was slightly delayed (70%) within 7 days compared with that from collagen gel (Col-gel, 85%), which is widely used in BMP-2 delivery. The BMP-2 released from Thio-CS increased osteoblastic cell differentiation but did not show any cytotoxicity until 21 days. Analysis of the in vivo ectopic bone formation at 4 weeks of posttransplantation showed that use of Thio-CS for BMP-2 delivery induced more bone formation to a greater extent (1.8 fold) than that of Col-gel. However, bone mineral density in both bones was equivalent, regardless of Thio-CS or Col-gel carrier. Taken together, Thio-CS system might be useful for delivering osteogenic protein BMP-2 and present a promising bone regeneration strategy.

Bae, In-Ho; Jeong, Byung-Chul; Kim, Sun-Hun; Koh, Jeong-Tae

2013-01-01

66

Local delivery of FTY720 accelerates cranial allograft incorporation and bone formation  

PubMed Central

Endogenous stem cell recruitment to the site of skeletal injury is key to enhanced osseous remodeling and neovascularization. To this end, this study utilized a novel bone allograft coating of poly(lactic-co-glycolic acid) (PLAGA) to sustain the release of FTY720, a selective agonist for sphingosine 1-phosphate (S1P) receptors, from calvarial allografts. Uncoated allografts, vehicle-coated, low dose FTY720 in PLAGA (1:200 w:w) and high dose FTY720 in PLAGA (1:40) were implanted into critical size calvarial bone defects. The ability of local FTY720 delivery to promote angiogenesis, maximize osteoinductivity and improve allograft incorporation by recruitment of bone progenitor cells from surrounding soft tissues and microcirculation was evaluated. FTY720 bioactivity after encapsulation and release was confirmed with sphingosine kinase 2 assays. HPLC-MS quantified about 50% loaded FTY720 release of the total encapsulated drug (4.5 µg) after 5 days. Following 2 weeks of defect healing, FTY720 delivery led to statistically significant increases in bone volumes compared to controls, with total bone volume increases for uncoated, coated, low FTY720 and high FTY720 of 5.98, 3.38, 7.2 and 8.9 mm3, respectively. The rate and extent of enhanced bone growth persisted through week 4 but, by week 8, increases in bone formation in FTY720 groups were no longer statistically significant. However, micro-computed tomography (microCT) of contrast enhanced vascular ingrowth (MICROFIL®) and histological analysis showed enhanced integration as well as directed bone growth in both high and low dose FTY720 groups compared to controls.

Huang, Cynthia; Das, Anusuya; Barker, Daniel; Tholpady, Sunil; Wang, Tiffany; Cui, Quanjun; Ogle, Roy

2012-01-01

67

Frontiers in Nutrition and Cancer Prevention: Online CME Series - Registration  

Cancer.gov

Frontiers in Nutrition and Cancer Prevention: Online CME SeriesRegistration Form Is Curcumin the Spice of Life? A Look at Cancer Prevention Evidence Tuesday, May 17, 20111:00 – 2:30 pm EDT Registration is now closed.

68

CME Onset and Take-Off  

NASA Technical Reports Server (NTRS)

For understanding and eventually predicting coronal mass ejections/eruptive flares, two critical questions must be answered: What is the mechanism for eruption onset, and what is the mechanism for the rapid acceleration? We address these questions in the context of the breakout model using 2.5D MHD simulations with adaptive mesh refinement (AMR). The AMR capability allowed us to achieve ultra-high numerical resolution and, thereby, determine the influence of the effective Lundquist number on the eruption. Our calculations show that, at least, for the breakout model, the onset of reconnection external to the highly sheared filament channel is the onset mechanism. Once this reconnection turns on, eruption is inevitable. However, as long as this is the only reconnection in the system, the eruption remains slow. We find that the eruption undergoes an abrupt "take-off" when the flare reconnection below the erupting plasmoid develops significant reconnection jets. We conclude that in fast CMEs, flare reconnection is the primary mechanism responsible for both flare heating and CME acceleration. We discuss the implications of these results for SDO observations and describe possible tests of the model.

Antiochos, S. K.; Karpen, J. T.; DeVore, C. R.

2011-01-01

69

Translating a health behavior change intervention for delivery to 2-year college students: the importance of formative research.  

PubMed

Young adults are at risk for weight gain in the transition to independent adulthood; 2-year college students are at greater risk and understudied relative to 4-year students. This project conducted formative research for a randomized controlled weight gain prevention trial among 2-year college students, to ensure appropriateness of content and delivery of a curriculum originally developed for 4-year college students. Data were collected from community college students, faculty, and staff from October 2009 to August 2011. Work included focus groups and key informant interviews, curriculum pilot testing, and social network and support website beta testing. Based on focus groups and interviews, program content, course delivery modes, and communication channels were adjusted to meet population interests and preferences. The course was delivered successfully in pilot testing, and the website was received well by beta testers. Formative work successfully guided program adaptations to address population needs. PMID:24904699

Linde, Jennifer A; Sevcik, Sarah M; Petrich, Christine A; Gardner, Jolynn K; Laska, Melissa N; Lozano, Paula; Lytle, Leslie A

2014-06-01

70

Dendrimer-assisted formation of fluorescent nanogels for drug delivery and intracellular imaging.  

PubMed

Although, in general, nanogels present a good biocompatibility and are able to mimic biological tissues, their unstability and uncontrollable release properties still limit their biomedical applications. In this study, a simple approach was used to develop dual-cross-linked dendrimer/alginate nanogels (AG/G5), using CaCl2 as cross-linker and amine-terminated generation 5 dendrimer (G5) as a cocrosslinker, through an emulsion method. Via their strong electrostatic interactions with anionic AG, together with cross-linker Ca(2+), G5 dendrimers can be used to mediate the formation of more compact structural nanogels with smaller size (433 ± 17 nm) than that (873 ± 116 nm) of the Ca(2+)-cross-linked AG nanogels in the absence of G5. Under physiological (pH 7.4) and acidic (pH 5.5) conditions, the sizes of Ca(2+)-cross-linked AG nanogels gradually decrease probably because of their degradation, while dual-cross-linked AG/G5 nanogels maintain a relatively more stable structure. Furthermore, the AG/G5 nanogels effectively encapsulate the anticancer drug doxorubicin (Dox) with a loading capacity 3 times higher than that of AG nanogels. The AG/G5 nanogels were able to release Dox in a sustained way, avoiding the burst release observed for AG nanogels. In vitro studies show that the AG/G5-Dox NGs were effectively taken up by CAL-72 cells (a human osteosarcoma cell line) and maintain the anticancer cytotoxicity levels of free Dox. Interestingly, G5 labeled with a fluorescent marker can be integrated into the nanogels and be used to track the nanogels inside cells by fluorescence microscopy. These findings demonstrate that AG/G5 nanogels may serve as a general platform for therapeutic delivery and/or cell imaging. PMID:24432789

Gonçalves, Mara; Maciel, Dina; Capelo, Débora; Xiao, Shili; Sun, Wenjie; Shi, Xiangyang; Rodrigues, João; Tomás, Helena; Li, Yulin

2014-02-10

71

Can a halo CME from the limb be geoeffective?  

NASA Astrophysics Data System (ADS)

The probability for a halo coronal mass ejection (CME) to be geoeffective is assumed to be higher the closer the CME launch site is located to the solar central meridian. However, events far from the central meridian may produce severe geomagnetic storms, like the case in April 2000. In this work, we study the possible geoeffectiveness of full halo CMEs with the source region situated at solar limb. For this task, we select all limb full halo (LFH) CMEs that occurred during solar cycle 23, and we search for signatures of geoeffectiveness between 1 and 5 days after the first appearance of each CME in the LASCO C2 field of view. When signatures of geomagnetic activity are observed in the selected time window, interplanetary data are carefully analyzed in order to look for the cause of the geomagnetic disturbance. Finally, a possible association between geoeffective interplanetary signatures and every LFH CME in solar cycle 23 is checked in order to decide on the CME's geoeffectiveness. After a detailed analysis of solar, interplanetary, and geomagnetic data, we conclude that of the 25 investigated events, there are only four geoeffective LFH CMEs, all coming from the west limb. The geoeffectiveness of these events seems to be moderate, turning to intense in two of them as a result of cumulative effects from previous mass ejections. We conclude that ejections from solar locations close to the west limb should be considered in space weather, at least as sources of moderate disturbances.

Cid, C.; Cremades, H.; Aran, A.; Mandrini, C.; Sanahuja, B.; Schmieder, B.; Menvielle, M.; Rodriguez, L.; Saiz, E.; Cerrato, Y.; Dasso, S.; Jacobs, C.; Lathuillere, C.; Zhukov, A.

2012-11-01

72

Numerical Simulation of a Slow Streamer-Blowout CME  

NASA Astrophysics Data System (ADS)

We present a 3D numerical MHD simulation of the 2008 Jun 2 gradual streamer blowout CME that had virtually no identifiable low coronal signatures. We energize the field by simple footpoint shearing along the source region's polarity inversion line and model the background solar wind structure using an ?2MK isothermal wind and a low-order potential field source surface representation of the CR2070 synoptic magnetogram. Our results show that the CME ``initiation’’ is obtained by slowly disrupting the quasi-steady-state configuration of the helmet streamer, resulting in the standard eruptive flare picture that ejects the sheared fields, but very slowly, on a relatively large scale, and with very little magnetic energy release. We obtain a relatively slow CME eruption of order the background solar wind speed and argue that these slow streamer blowout CMEs (now also known as ``stealth CMEs’’) are simply at the lowest end of the CME energy distribution. We present comparisons of the CME propagation through the corona (?15Rs) in synthetic white-light images derived from the simulation density structure with multi-spacecraft coronagraph data from STEREO/SECCHI and SOHO/LASCO.

Lynch, Benjamin J.; Masson, Sophie; Li, Yan; DeVore, C. Richard; Luhmann, Janet; Antiochos, Spiro K.

2014-06-01

73

Reconnection Onset in the Breakout Model for CME Initiation  

NASA Technical Reports Server (NTRS)

Fast coronal mass ejections (CMEs) are the most massive explosions in the heliosphere, and the primary drivers of geoeffective space weather. Although it is generally agreed that magnetic reconnection is the key to fast CME initiation, different models incorporate reconnection in different ways. One promising model --- the breakout scenario --- involves reconnection in two distinct yet interconnected locations: breakout reconnection ahead of the CME, and flare reconnection behind it. We will discuss what we have learned about the early evolution of breakout and flare reconnection from recent high-resolution 2.5D adaptively refined MHD simulations of CME initiation, including the evolving properties of the breakout and flare current sheets, the conditions that trigger reconnection onset in each sheet, the ensuing positive feedback between breakout and flare reconnections, and implications for electron acceleration in flares.

Karpen, Judy T.; DeVore, C. R.; Antiochos, S. K.

2010-01-01

74

Sponsorship and conflicts of interests in CME: the Italian experience.  

PubMed

Pursuant to the Italian healthcare framework, sponsorship of Continuing Medical Education (CME) for healthcare professionals governs the relationship between the medical industry and the healthcare sector, as public institutions are directly involved in it. Sponsorship is based on a voluntarily sharing of mutual benefits between two contracting parties, namely the sponsor and the sponsorship beneficiary, whose interests are relevant to the same degree. To avoid conflicts of interests from occurring, sponsorship shall comply with two ethical standards: 1) the contracting parties shall verify if their interests about CME activities converge or conflict; 2) the sponsorship contract shall be published and advertised to disclose what kind of commitment the contracting parties undertook. When entering a CME sponsorship contract as sponsorship beneficiary, Italian local health authorities may rely on a code of conduct which lays down all principles, criteria and proceedings that shall apply. PMID:19705637

Villani, G

2009-03-01

75

Cme Evolution In The Interplanetary Space Based On Stereo Observations.  

NASA Astrophysics Data System (ADS)

STEREO/SECCHI observations help identify the true 3-D geometric structure of CMEs and track their true evolution in the inner heliosphere. Using STEREO observations, it is possible to obtain the true speed of CMEs, which is key in predicting the arrival time of CMEs at Earth (Gopalswamy et al. 2001). From the STEREO data, we are able to track and measure CMEs in 3-D by using Raytrace model (Thernisien et al 2006, 2009), which is free from projection effects and thus result in true CME velocities. Studied study 5 CME events, we found that the acceleration/deceleration of CMEs occur within 50 Rs from the Sun, after that the CME velocity converges to the narrow range (Poomvises et al 2010). Additionally, we found that expansion velocity of CMEs also converges to a narrow range after 50 Rs. The observations are consistent with the theoretical flux rope model. The CME evolution can be explained by different forces that act on the CME: Lorentz force, thermal pressure force, gravity force, aero-dynamic drag force, and the magnetic drag force. The drag coefficient typically varies between 2.5 to 3.0, which is much smaller than the factor of twelve suggested by earlier studies. Moreover, the value of the polytropic index has been found to be between 1.35 to 1.60. Therefore, we have been able to narrow down the range of values for the drag coefficient and the polytropic index, which help in improve the prediction of CME travel time.

Poomvises, Watanachak; Gopalswamy, N.; Zhang, J.

2011-05-01

76

Coronal Magnetic Reconnection Driven by CME Expansion—the 2011 June 7 Event  

NASA Astrophysics Data System (ADS)

Coronal mass ejections (CMEs) erupt and expand in a magnetically structured solar corona. Various indirect observational pieces of evidence have shown that the magnetic field of CMEs reconnects with surrounding magnetic fields, forming, e.g., dimming regions distant from the CME source regions. Analyzing Solar Dynamics Observatory (SDO) observations of the eruption from AR 11226 on 2011 June 7, we present the first direct evidence of coronal magnetic reconnection between the fields of two adjacent active regions during a CME. The observations are presented jointly with a data-constrained numerical simulation, demonstrating the formation/intensification of current sheets along a hyperbolic flux tube at the interface between the CME and the neighboring AR 11227. Reconnection resulted in the formation of new magnetic connections between the erupting magnetic structure from AR 11226 and the neighboring active region AR 11227 about 200 Mm from the eruption site. The onset of reconnection first becomes apparent in the SDO/AIA images when filament plasma, originally contained within the erupting flux rope, is redirected toward remote areas in AR 11227, tracing the change of large-scale magnetic connectivity. The location of the coronal reconnection region becomes bright and directly observable at SDO/AIA wavelengths, owing to the presence of down-flowing cool, dense (1010 cm-3) filament plasma in its vicinity. The high-density plasma around the reconnection region is heated to coronal temperatures, presumably by slow-mode shocks and Coulomb collisions. These results provide the first direct observational evidence that CMEs reconnect with surrounding magnetic structures, leading to a large-scale reconfiguration of the coronal magnetic field.

van Driel-Gesztelyi, L.; Baker, D.; Török, T.; Pariat, E.; Green, L. M.; Williams, D. R.; Carlyle, J.; Valori, G.; Démoulin, P.; Kliem, B.; Long, D. M.; Matthews, S. A.; Malherbe, J.-M.

2014-06-01

77

Prediction of Active-Region CME Productivity from Magnetograms  

NASA Technical Reports Server (NTRS)

We report results of an expanded evaluation of whole-active-region magnetic measures as predictors of active-region coronal mass ejection (CME) productivity. Previously, in a sample of 17 vector magnetograms of 12 bipolar active regions observed by the Marshall Space Flight Center (MSFC) vector magnetograph, from each magnetogram we extracted a measure of the size of the active region (the active region s total magnetic flux a) and four measures of the nonpotentiality of the active region: the strong-shear length L(sub SS), the strong-gradient length L(sub SG), the net vertical electric current I(sub N), and the net-current magnetic twist parameter alpha (sub IN). This sample size allowed us to show that each of the four nonpotentiality measures was statistically significantly correlated with active-region CME productivity in time windows of a few days centered on the day of the magnetogram. We have now added a fifth measure of active-region nonpotentiality (the best-constant-alpha magnetic twist parameter (alpha sub BC)), and have expanded the sample to 36 MSFC vector magnetograms of 31 bipolar active regions. This larger sample allows us to demonstrate statistically significant correlations of each of the five nonpotentiality measures with future CME productivity, in time windows of a few days starting from the day of the magnetogram. The two magnetic twist parameters (alpha (sub 1N) and alpha (sub BC)) are normalized measures of an active region s nonpotentially in that they do not depend directly on the size of the active region, while the other three nonpotentiality measures (L(sub SS), L(sub SG), and I(sub N)) are non-normalized measures in that they do depend directly on active-region size. We find (1) Each of the five nonpotentiality measures is statistically significantly correlated (correlation confidence level greater than 95%) with future CME productivity and has a CME prediction success rate of approximately 80%. (2) None of the nonpotentiality measures is a significantly better CME predictor than the others. (3) The active-region phi shows some correlation with CME productivity, but well below a statistically significant level (correlation confidence level less than approximately 80%; CME prediction success rate less than approximately 65%). (4) In addition to depending on magnetic twist, CME productivity appears to have some direct dependence on active-region size (rather than only an indirect dependence through a correlation of magnetic twist with active-region size), but it will take a still larger sample of active regions (50 or more) to certify this. (5) Of the five nonpotentiality measures, L(sub SG) appears to be the best for operational CME forecasting because it is as good or better a CME predictor than the others and it alone does not require a vector magnetogram; L(sub SG) can be measured from a line-of-sight magnetogram such as from the Michelson Doppler Imager (MDI) on the Solar and Heliospheric Observatory (SOHO).

Falconer, D. A.; Moore, R. L.; Gary, G. A.

2004-01-01

78

Obstetrician/Gynecologists and Postpartum Mental Health: Differences between CME Course Takers and Nontakers  

ERIC Educational Resources Information Center

Introduction: Continuing medical education (CME) courses are an essential component of professional development. Research indicates a continued need for understanding how and why physicians select certain CME courses, as well as the differences between CME course takers and nontakers. Purpose: Obstetrician-gynecologists (OB-GYNs) are health care…

Leddy, Meaghan A.; Farrow, Victoria A.; Joseph, Gerald F., Jr.; Schulkin, Jay

2012-01-01

79

Solar Flare and Cme Prediction From Photospheric Magnetic Field Measurements  

Microsoft Academic Search

The coronal mass ejection that associated with a solar flare produces powerful mag- netospheric disturbances. The numerical 3D MHD model for prediction of CME and flares is proposed. The photospheric magnetic measurements are used as boundary conditions. The scenario of vertical current sheet creation is demonstrated for several solar flares. The new version of the PERSVET code is developed for

A. I. Podgorny; I. M. Podgorny

2002-01-01

80

SECCHI View of CME Dynamics: Observations and Theory  

Microsoft Academic Search

LASCO observations in the region of 2--30 Rs established that CMEs can be understood as erupting magnetic flux ropes based on comparison with LASCO\\/EIT observations (Chen et al. 1997; Thernisien et al. 2006) and that the observed dynamics in this regime can be correctly described by the erupting flux rope (EFR) model (Chen 1996). Beyond 30 Rs, however, CME morphology

V. Kunkel; J. Chen

2008-01-01

81

A Special Flare-CME Event on April 21, 2002  

Microsoft Academic Search

The time and location of magnetic reconnection are indicated by radio (Nobeyama Radio Heliograph and Polarimeters, Hiraiso and Chinese radio spectrographs) and multi-wavelength (SOHO and TRACE satellites) data in a selected flare-CME event on April 21, 2002. Two hour radio burst started at high frequencies (maximum around 10 GHz). After that, a radio ejection at 17 GHz from one foot

Huang Guang-Li

2005-01-01

82

Improving CME: Using Participant Satisfaction Measures to Specify Educational Methods  

ERIC Educational Resources Information Center

Imagine having developed a continuing medical education (CME) initiative to educate physicians on updated guidelines regarding high cholesterol in adults. This initiative consisted of didactic presentations and case-based discussions offered in 5 major US cities, followed by a Web-based enduring component to distill key points of the live…

Olivieri, Jason J.; Regala, Roderick P.

2013-01-01

83

Which CME cone type is closer to observations?  

NASA Astrophysics Data System (ADS)

Recently, CME cone models are widely used for inferring three dimensional structures of CMEs and their propagation through the heliosphere, especially for the input parameters of CME propagation models. However, there has been no observational test which cone type is closer to observations. In this study, we investigate which cone model is proper for halo CME morphology using 33 CMEs which are identified as halo CMEs by one spacecraft and as limb CMEs by the other ones. These CMEs were taken by SOHO/LASCO and STEREO/SECCHI during the period from 2010 December to 2011 June when two spacecraft were separated by 90±10 degrees, which allow us to directly estimate their angular widths from observations. From geometrical parameters of these CMEs such as their front curvature, they are classified into two groups: shallow cone CMEs (5 events), whose curvature radius is equal to the distance of CME front from the center of the Sun, and near full-cone CMEs (28 events), whose front has a semi-circle shape. Noting that the previous cone models are based on flat cone or shallow cone shapes, our results imply that a cone model based on the full cone shape should be developed.

Na, Hyeonock; Jang, Soojeong; Lee, Jea-Ok; LEE, Harim; Moon, Yong-Jae

2014-06-01

84

Local Delivery of TGF-b Antibodies to Prevent Neointima Formation after Balloon Injury in a Pig Coronary Artery Model.  

PubMed

BACKGROUND: The formation of neointima after vessel injury results from smooth muscle cell proliferation and extracellular matrix secretion. This process is activated by multiple growth factor release. Among these, Transforming Growth Factor-b (TGF-b) has been shown to play an important role. We hypothesized that local delivery of TGF-b antibodies could reduce neointima formation after balloon angioplasty. METHODS AND RESULTS: Using autoperfusion double-balloon catheters (Baxter, Irvine, California), we infused polyclonal TGF-b antibodies in 30 minutes, immediately after oversized balloon angioplasty in pig coronary arteries. Eleven coronary arteries received 100 m anti-TGF-b and thirteen served as controls. Animals were sacrificed 10 weeks later; coronary segments were harvested and processed for histologic quantitative assessment of the neointima. The extent of injury was similar in treated versus control vessels (39% +/- 5% vs. 30% +/- 4%) and there was no difference in intimal thickening (0.63 +/- 0.19 mm for treated vs. 0.52 +/- 0.12 mm for controls). A previously validated restenosis injury index (ratio of neointimal area to total wall area over extent of injury) was also similar in both groups, 1.46 +/- 0.15 for treated versus 1.55 +/- 0.14 for controls. CONCLUSION: Local delivery of a single dose of TGF-b antibodies failed to demonstrate a benefit on neointima formation in a pig coronary artery model. PMID:10762824

Paiement; Bertrand; Scortichini; Meerkin; Cloutier; Methot; Leung; Bonan

1998-10-01

85

Formation of artificial multicompartment vesosome and dendrosome as prospected drug and gene delivery carriers.  

PubMed

Extensive studies in the last fifty years on the development of multifunctional liposomes have improved their drug delivery potential. Specifically, they fulfill to a significant degree the requirements which an effective drug carrier should exhibit, i.e. biocompatibility, biodegradability, drug encapsulation and protection of the drug, targeting to specific cells, reasonable stability in the biological milieu, transport through cell membranes and controlled drug release. However, despite these properties which have been achieved to a significant degree through molecular engineering of the liposome bilayers, a universal liposomal carrier has not yet been developed since it is rather difficult for the above properties to be simultaneously fulfilled. For this purpose a multicompartmentalization strategy was applied through which liposomes encapsulating smaller ones in their aqueous core were prepared. Multicompartment systems have also been prepared by encapsulation of dendrimers in the aqueous core of liposomes. In this manner drug delivery systems were prepared providing a double protection to drugs encapsulated inside the core of the small liposomes or incorporated in dendrimers. The external liposomal bilayer is also susceptible to multifunctionalization while their drug release can more effectively been tuned compared to single-compartment systems. Modular-type strategies have been employed for the preparation of these multicompartment systems. Thus, unilamellar liposomes and mono-dispersed dendrimers are selected as the drug delivery modules from which universal multifunctional and multicompartment drug delivery systems have been obtained i.e. vesosomes, which are liposomes encapsulating smaller liposomes and dendrosomes, which are liposomes encapsulating dendrimers. Examples of the application of drug and gene delivery employing vesosomes and dendrosomes as carriers are critically discussed. PMID:23707326

Paleos, Constantinos M; Tsiourvas, Dimitris; Sideratou, Zili; Pantos, Alexandros

2013-08-28

86

CME Topologies and Observed Flare Features: Extending the Standard Flare/CME Model to 3D  

NASA Astrophysics Data System (ADS)

We study the topology of erupting non-linear force-free configurations of five sigmoidal active regions observed with Hinode/XRT and SDO/AIA. The magnetic field models are computed using the flux rope insertion method and unstable models are utilized to represent the erupting configurations. Analysis of the topology shows that the quasi-separatrix layers (QSLs) in the chromosphere match well the flare ribbons observed in these regions. The evolution of the flare ribbons is captured by the a sequence of QSLs from unstable NLFFF solutions. Post-flare loops are fit well by field lines lying under the hyperbolic flux tube in the models. We show a correspondence in the evolution of the post-flare loops from a strong to weak sheared state and the behavior of the field lines as the flux rope expands in the model. We use this kind of topology analysis to extend the standard CME/flare model to full 3D in observed configurations and find implications to reconnection in 3D. In addition we compute the reconnected flux in one of the regions region and using information from the models constrain how much energy has been released during the event.

Savcheva, A. S.

2013-12-01

87

Methods and apparatuses for reagent delivery, reactive barrier formation, and pest control  

DOEpatents

A reagent delivery method includes positioning reagent delivery tubes in contact with soil. The tubes can include a wall that is permeable to a soil-modifying reagent. The method further includes supplying the reagent in the tubes, diffusing the reagent through the permeable wall and into the soil, and chemically modifying a selected component of the soil using the reagent. The tubes can be in subsurface contact with soil, including groundwater, and can be placed with directional drilling equipment independent of groundwater well casings. The soil-modifying reagent includes a variety of gases, liquids, colloids, and adsorbents that may be reactive or non-reactive with soil components. The method may be used inter alia to form reactive barriers, control pests, and enhance soil nutrients for microbes and plants.

Gilmore, Tyler [Pasco, WA; Kaplan, Daniel I [Aiken, SC; Last, George [Richland, WA

2002-07-09

88

Three-Dimensional CME Reconstruction Using Geometric and Polarimetric Localization  

NASA Astrophysics Data System (ADS)

The geometric localization technique [Pizzo and Biesecker, 2004] utilizes a series of lines-of-sight from two space-based coronagraphs to determine gross propagation characteristics of coronal mass ejections (CMEs) in three-dimensional space. The polarimetric localization technique [Moran and Davila, 2004] uses the percent polarization observed by a single coronagraph to obtain a three-dimensional reconstruction of a CME. We apply both techniques to STEREO/SECCHI/COR2 data to determine the speed and direction of propagation, as well as the size, shape, and orientation of some recent CMEs, including the event of 3 April 2010. The results obtained from this analysis can be used as inputs to the numerical MHD code, Enlil, which will track the evolution of the CME and its interaction with the solar wind.

de Koning, C. A.; Pizzo, V. J.

2010-12-01

89

Properties and processes that influence CME geo-effectiveness  

NASA Astrophysics Data System (ADS)

The geo-effectiveness of coronal mass ejections (CME) is determined by a complex chain of processes. This paper highlights this fact by first discussing the importance of CMEs intrinsic properties set at the Sun (e.g., trajectory, eruption process, orientation, etc.). We then review other key processes that may occur during propagation (e.g., shocks, compressions, magnetic flux erosion) and in the specific interaction with Earth's magnetosphere (e.g., magnetic properties, preconditioning mechanisms). These processes sequentially have a significant influence on the final geo-effectiveness of CMEs. Their relative importance is discussed. While the CME's trajectory, magnetic field orientation, velocity and their duration as set at the Sun certainly are key ingredients to geo-effectiveness, other processes and properties, that at first appear secondary, often may be as important.

Lavraud, Benoit; Rouillard, Alexis

2014-01-01

90

Controlled delivery of platelet-rich plasma-derived growth factors for bone formation.  

PubMed

Platelet-rich plasma (PRP) represents an autologous source of growth factors essential for bone regeneration. The clinical efficacy of PRP is, however, unpredictable, and this is likely due to the inefficient and inconsistent delivery of PRP-derived growth factors. Previous investigations have shown that current methods of PRP preparation result in a premature release of the relevant bone stimulatory factors. As successful bone regeneration requires multiple factors presented in a physiologic temporal and spatial cascade, the objective of this study is to control the bioavailability of PRP-derived growth factors using a hydrogel carrier system. Specifically, the release of platelet-derived growth factor, transforming growth factor beta-1, and insulin-like growth factor from two types of alginate carriers was compared over time. The effects of the released factors on the growth and alkaline phosphatase (ALP) activity of human osteoblast-like cells were also evaluated. It was found that factor release profiles varied as function of carrier type, and binding of growth factors to the alginate matrix also modulated their release. The bioactivity of released factors was maintained in vitro and they promoted cell proliferation and ALP activity. These results demonstrate the potential of this autologous multifactor delivery system for controlling the bioavailability of PRP-derived factors. Future studies will focus on optimizing this system to increase the clinical efficacy of PRP by matching the distribution and temporal sequencing of PRP-derived factors to the bone healing cascade. PMID:18181109

Lu, Helen H; Vo, Jennifer M; Chin, Hsin Sheila; Lin, Jeffrey; Cozin, Matthew; Tsay, Rick; Eisig, Sidney; Landesberg, Regina

2008-09-15

91

Suppression of FVIII Inhibitor Formation in Hemophilic Mice by Delivery of Transgene Modified Apoptotic Fibroblasts  

PubMed Central

The development of inhibitory antibodies to factor VIII (FVIII) is currently the most significant complication of FVIII replacement therapy in the management of patients with severe hemophilia A. Immune tolerance protocols for the eradication of inhibitors require daily delivery of intravenous FVIII for at least 6 months and are unsuccessful in 20–40% of treated patients. We hypothesize that tolerance can be induced more efficiently and reliably by delivery of FVIII antigen within autologous apoptotic cells (ACs). In this study, we demonstrated suppression of the T cell and inhibitor responses to FVIII by infusion of FVIII expression vector modified apoptotic syngeneic fibroblasts in both naive and preimmunized hemophilia A mice. ACs without FVIII antigen exerted modest generalized immune suppression mediated by anti-inflammatory signals. However, FVIII expressing apoptotic syngeneic fibroblasts produced much stronger antigen-specific immune suppression. Mice treated with these fibroblasts generated CD4+ T cells that suppressed the immune response to FVIII after adoptive transfer into naive recipients and antigen-specific CD4+CD25+ regulatory T cells (Tregs) that inhibited the proliferation of FVIII responsive effector T cells in vitro. These preclinical results demonstrate the potential for using FVIII vector modified autologous ACs to treat high-titer inhibitors in patients with hemophilia A.

Su, Rui-Jun; Epp, Angela; Latchman, Yvette; Bolgiano, Doug; Pipe, Steven W; Josephson, Neil C

2009-01-01

92

Formation of thermo-sensitive polyelectrolyte complex micelles from two biocompatible graft copolymers for drug delivery.  

PubMed

Thermo-sensitive polyelectrolyte complex (PEC) micelles assembled from two biocompatible graft copolymers chitosan-g-poly(N-isopropylacrylamide) (CS-g-PNIPAM) and carboxymethyl cellulose-g-poly(N-isopropylacrylamide) (CMC-g-PNIPAM) were prepared for delivery of 5-fluorouracil (5-FU). The PEC micelles showed a narrow size distribution with core-shell structure, in which the core formed from positively charged CS and negatively charged CMC by electrostatic interactions and the shell formed from thermo-sensitive PNIPAM. The synthesized PEC micelles have lower critical solution temperatures (LCST) in the region of 37°C, which is favorable for smart drug delivery applications. The hydrogen bondings between PEC micelles and 5-FU increased the drug loading. Changing temperature, pH or ionic strength, a sustained and controlled release was observed due to the deformation of PEC micelles. Adding glutaraldehyde, a chemical crosslinking reagent, was an efficient way to reinforce the micelles structure and decrease the initial burst release. Cytotoxicity assays showed that drug-loaded PEC micelles retained higher cell inhibition efficiency in HeLa cells. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2163-2172, 2014. PMID:23894021

Li, Guiying; Meng, Yanfeng; Guo, Lei; Zhang, Ting; Liu, Junshen

2014-07-01

93

Determination of the coefficient of moisture expansion (CME)  

NASA Astrophysics Data System (ADS)

A test facility for the measurement of the length variation of polymer composites due to moisture evaporation is described. The measurement method is based on commercial laser interferometers with a resolution of 10nm and working under vacuum conditions yields a total accuracy of 0,1?m. The high sensitivity and resolution of the test facility is shown by CTE experiments with copper and Invar samples. The CTE results are in the expected range although the considered temperature regime is very small. CME measurements were performed on simple lay ups - unidirectional and bidirectional material - of carbon fibre reinforced polymers, which were preconditioned in water at a temperature of 50°C. Two methods for the determination of ?m - determination of the initial and final sample weight (method 1) - online-measurement of the sample weight during outgassing under vacuum condition (method 2) are presented and a comparison of the CME results confirms the time effectiveness and reliability of the method 2. The CME values for the chosen material are in the range of 5E-6/% to 1E-2/%.

Poenninger, A.; Defoort, B.

2003-09-01

94

The Launch and Early Evolution of a CME Flux Rope  

NASA Astrophysics Data System (ADS)

We present a narrative of the launch and early evolution of a flux rope comprised within the coronal mass ejection (CME) that left the Sun on 12 December 2008. The two STEREO spacecraft were near quadrature at that time, so we were afforded a unique view of this flux rope from along its edge and down its barrel simultaneously using STEREO's EUVI cameras. We find that a sequence of seemingly separate CMEs observed in the corona and solar wind were actually manifestations of the same flux rope passing through the imagers' fields of view at different times. The launch begins with a small solar flare at the northern-most end of a pre-formed flux rope, which lifts off from this end first via the tether-cutting mechanism. Other segments of the flux rope follow this launch, and a filament is observed to roll over the top of these segments and pour back into the solar disk, thereby indicating the mass draining mechanism at play. The southern end of the flux rope remains fixed to the Sun, leading to an eventual stress-fracture and bisection of the flux rope. The severed southern end eventually disconnects from the Sun a day later via what appears to be the kink instability mechanism. This narrative, describing the interplay between three separate onset mechanisms for simple CME during a period of extremely low solar activity, demonstrates the complexity of the physics of CME onset.

Howard, Tim A.; DeForest, C.

2013-07-01

95

Type II Radio Bursts as an Indicator of CME Location  

NASA Astrophysics Data System (ADS)

We examined a subset of nine low-frequency radio events with type II radio bursts that drifted below 2 megahertz and were detected by the WAVES investigation on the WIND spacecraft. For each event, we identified the associated coronal mass ejection (CME) and derived the electron density using a model of solar wind plasma frequency (fp ? 9 * ne1/2, where fp is plasma frequency in kHz and ne is electron density in cm-3) . We also used the pb_inverter program in SolarSoft developed by Howard and Hayes to examine the electron density structure. Expanding on the Van De Hulst process of inverting polarized brightness measurements, the program inverts total brightness measurements from SOHO LASCO images to extract electron density information. From the electron density inferred from radio spectra, we derived the location of the CME using five standard electron density to height models (Leblanc, 1996; Saito, 1977; Bougeret, 1984; Alvarez, 1973; and Fainberg, 1971). Using images from the LASCO instrument on SOHO and the SECCHI instrument on STEREO, we extracted locations of the leading edge of the CME and compared the heights and velocities to those found using the frequency data. For the lowest frequency events, we also compared our results to the outputs of ENLIL, a time-dependent, three-dimensional, MHD model of the heliosphere hosted by the Community Coordinated Modeling Center (CCMC) at NASA Goddard Space Flight Center.

Quirk, C. A.; St Cyr, O. C.; Henning, C.; Xie, H.; Gilbert, H. R.; Orlove, M.; Gopalswamy, N.; Odstrcil, D.

2011-12-01

96

CME Reconstruction from Three Viewpoints Via Simulation Morphing  

NASA Astrophysics Data System (ADS)

The problem of reconstructing the three dimensional (3D) density distribution of a coronal mass ejection (CME) from three simultaneous coronagraph observations is timely in that the COR1 and COR2 coronagraphs on the dual-spacecraft STEREO mission complement the LASCO coronagraphs on the SOHO satellite and the Mk4 on Mauna Loa. While the separation angle between the STEREO spacecraft and the Earth depends on the time since the launch in 2006, the reconstruction problem is always severely under-informed. So far, all 3D reconstruction efforts have made use of relatively simple parameterized models in order to determine the 3D structure of the CME. Such approaches do not utilize the power of 3D MHD simulation to inform the reconstruction. This papers considers the situation in which a specific CME event observed in corongraphs from three viewpoints is later simulated by solving MHD equations. The reconstruction is then subjected to an invertible morphological morphing operator chosen so that morphed MHD simulation is most consistent with the 3-viewpoint coronagraph data. The morphological operations are explained mathematically and synthetic examples are given. The practical application to reconstructing CMEs from STEREO and SOHO data is discussed.

Frazin, R. A.

2012-12-01

97

Dependence of Geomagnetic Storms on Their Associated Halo CME Parameters  

NASA Astrophysics Data System (ADS)

We compare the geoeffective parameters of halo coronal mass ejections (CMEs). We consider 50 front-side full-halo CMEs (FFH CMEs), which are from the list of Michalek, Gopalswamy, and Yashiro ( Solar Phys. 246, 399, 2007), whose asymmetric-cone model parameters and earthward-direction parameter were available. For each CME we use its projected velocity [ V p], radial velocity [ V r], angle between cone axis and sky plane [ ?] from the cone model, earthward-direction parameter [ D], source longitude [ L], and magnetic-field orientation [ M] of its CME source region. We make a simple linear-regression analysis to find out the relationship between CME parameters and Dst index. The main results are as follows: i) The combined parameters [( V r D)1/2 and V r ?] have higher correlation coefficients [cc] with the Dst index than the other parameters [ V p and V r]: cc=0.76 for ( V r D)1/2, cc=0.70 for V r ?, cc=0.55 for V r, and cc=0.17 for V p. ii) Correlation coefficients between V r ? and Dst index depend on L and M; cc=0.59 for 21 eastern events [E], cc=0.80 for 29 western events [W], cc=0.49 for 17 northward magnetic-field events [N], and cc=0.69 for 33 southward magnetic-field events [S]. iii) Super geomagnetic storms (Dst?-200 nT) only appear in the western and southward magnetic-field events. The mean absolute Dst values of geomagnetic storms (Dst?-50 nT) increase with an order of E+N, E+S, W+N, and W+S events; the mean absolute Dst value (169 nT) of W+S events is significantly larger than that (75 nT) of E+N events. Our results demonstrate that not only do the cone-model parameters together with the earthward-direction parameter improve the relationship between CME parameters and Dst index, but also the longitude and the magnetic-field orientation of a FFH CME source region play a significant role in predicting geomagnetic storms.

Lee, Jae-Ok; Moon, Y.-J.; Lee, Kyoung-Sun; Kim, R.-S.

2014-06-01

98

Protein complexing in a methanogen suggests electron bifurcation and electron delivery from formate to heterodisulfide reductase.  

PubMed

In methanogenic Archaea, the final step of methanogenesis generates methane and a heterodisulfide of coenzyme M and coenzyme B (CoM-S-S-CoB). Reduction of this heterodisulfide by heterodisulfide reductase to regenerate HS-CoM and HS-CoB is an exergonic process. Thauer et al. [Thauer, et al. 2008 Nat Rev Microbiol 6:579-591] recently suggested that in hydrogenotrophic methanogens the energy of heterodisulfide reduction powers the most endergonic reaction in the pathway, catalyzed by the formylmethanofuran dehydrogenase, via flavin-based electron bifurcation. Here we present evidence that these two steps in methanogenesis are physically linked. We identify a protein complex from the hydrogenotrophic methanogen, Methanococcus maripaludis, that contains heterodisulfide reductase, formylmethanofuran dehydrogenase, F(420)-nonreducing hydrogenase, and formate dehydrogenase. In addition to establishing a physical basis for the electron-bifurcation model of energy conservation, the composition of the complex also suggests that either H(2) or formate (two alternative electron donors for methanogenesis) can donate electrons to the heterodisulfide-H(2) via F(420)-nonreducing hydrogenase or formate via formate dehydrogenase. Electron flow from formate to the heterodisulfide rather than the use of H(2) as an intermediate represents a previously unknown path of electron flow in methanogenesis. We further tested whether this path occurs by constructing a mutant lacking F(420)-nonreducing hydrogenase. The mutant displayed growth equal to wild-type with formate but markedly slower growth with hydrogen. The results support the model of electron bifurcation and suggest that formate, like H(2), is closely integrated into the methanogenic pathway. PMID:20534465

Costa, Kyle C; Wong, Phoebe M; Wang, Tiansong; Lie, Thomas J; Dodsworth, Jeremy A; Swanson, Ingrid; Burn, June A; Hackett, Murray; Leigh, John A

2010-06-15

99

STUDY OF THE 2007 APRIL 20 CME-COMET INTERACTION EVENT WITH AN MHD MODEL  

SciTech Connect

This study examines the tail disconnection event on 2007 April 20 on comet 2P/Encke, caused by a coronal mass ejection (CME) at a heliocentric distance of 0.34 AU. During their interaction, both the CME and the comet are visible with high temporal and spatial resolution by the STEREO-A spacecraft. Previously, only current sheets or shocks have been accepted as possible reasons for comet tail disconnections, so it is puzzling that the CME caused this event. The MHD simulation presented in this work reproduces the interaction process and demonstrates how the CME triggered a tail disconnection in the April 20 event. It is found that the CME disturbs the comet with a combination of a 180 deg. sudden rotation of the interplanetary magnetic field (IMF), followed by a 90 deg. gradual rotation. Such an interpretation applies our understanding of solar wind-comet interactions to determine the in situ IMF orientation of the CME encountering Encke.

Jia, Y. D.; Russell, C. T.; Jian, L. K. [IGPP, University of California, Los Angeles, CA 90095 (United States); Manchester, W. B.; Cohen, O.; Hansen, K. C.; Combi, M. R.; Gombosi, T. I. [CSEM, University of Michigan, Ann Arbor, MI, 48109 (United States); Vourlidas, A. [Solar Physics Branch, Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2009-05-01

100

Numerical Simulation of the January 2012 CME Event and its Propagation to the Earth Orbit  

NASA Astrophysics Data System (ADS)

The January 2012 coronal mass ejection (CME) was very strong, and produced colorful auroras and a strong geomagnetic storm, which was detected by the Wind spacecraft. We present the results of numerical investigation of the January 2012 CME propagation to the Earth orbit, where the plasma and magnetic field distribution are compared with the WIND data. The CME is launched at the solar surface. Adaptive mesh refinement technique allowed us to resolve fine details of the CME structure on its way toward 1 AU. In particular, the application of the level set method made it possible to track the CME surface. We also distinguished the complicated structure of the CME shock. Numerical simulation was performed with a Multi-Scale Fluid-Kinetic Simulation Suite (MS-FLUKSS) - a powerful tool for modeling discontinuous flows of partially ionized plasma in the presence of nonthermal ion components and turbulence.

Kryukov, I.; Borovikov, S. N.; Shen, F.; Pogorelov, N. V.; Wu, S.

2012-12-01

101

Evolution of two Flaring Active Regions With CME Association  

NASA Astrophysics Data System (ADS)

We study the coronal magnetic field structure of two active regions, one during solar activity minimum (June 2007) and another one during a more active time (January 2004). The temporal evolution was explored with the help of nonlinear force-free coronal magnetic field extrapolations of SOLIS/VSM and NAOJ/SFT photospheric vector magnetograms. We study the active region NOAA 10960 observed on 2007 June 7 with three SOLIS/VSM snapshots taken during a small C1.0 flare of time cadence 10 minutes and six snapshots during a quiet period. The total magnetic energy in the active region was approximately 3 × 1025 J. Before the flare the free magnetic energy was about 5~% of the potential field energy. A part of this excess energy was released during the flare, producing almost a potential configuration at the beginning of the quiet period. The return to an almost potential structure can be assigned to a CME as recorded by the SoHO/LASCO instrument on 2007 June 07 around 10 minutes after the flare peaked, so that whatever magnetic helicity was bodily removed from the structure. This was compared with active region 10540 observed on 2004 January 18 -- 21, which was analyzed with the help of vector magnetograph data from the Solar Flare Telescope in Japan of time cadence of about 1 day. The free energy was Efree? 66~% of the total energy which was sufficiently high to power a M6.1 flare on January 20, which was associated with a CME 20 minutes later. The activity of AR 10540 was significantly higher than for AR 10960, as was the total magnetic energy. Furthermore, we found the common feature that magnetic energy accumulates before the flare/CME and a significant part of the excess energy is released during the eruption.

Thalmann, J. K.; Wiegelmann, T.

2008-12-01

102

Particle Acceleration by CME-Driven Shock Waves  

NASA Technical Reports Server (NTRS)

In the largest solar energetic particle (SEP) events, acceleration occurs at shock waves driven out from the Sun by coronal mass ejections (CMEs). Peak particle intensities are a strong function of CME speed, although the intensities, spectra, and angular distributions of particles escaping the shock are highly modified by scattering on Alfven waves produced by the streaming particles themselves. Element abundances vary in complex ways because ions with different values of Q/A resonate with different parts of the wave spectrum, which varies with space and time. Just recently, we have begun to model these systematic variations theoretically and to explore other consequences of proton-generated waves.

Reames, Donald V.

1999-01-01

103

Sigmoid CME Source Regions at the Sun: Some Recent Results  

NASA Technical Reports Server (NTRS)

Identifying Coronal Mass Ejection (CME) precursors in the solar corona would be an important step in space weather forecasting, as well as a vital key to understanding the physics of CMEs. Twisted magnetic field structures are suspected of being the source of at least some CMEs. These features can appear sigmoid (S or inverse-S) shaped in soft X-ray (SXR) images. We review recent observations of these structures and their relation to CMEs, using soft X-ray (SXR) data from the Soft X-ray Telescope (SXT) on the Yohkoh satellite, and EUV data from the EUV Imaging Telescope (EIT) on the SOHO satellite. These observations indicate that the pre-eruption sigmoid patterns are more prominent in SXRs than in EUV, and that sigmoid precursors are present in over 50% of CMEs. These findings are important for CME research, and may potentially be a major component to space weather forecasting. So far, however, the studies have been subject to restrictions that will have to be relaxed before sigmoid morphology can be used as a reliable predictive tool. Moreover, some CMEs do not display a SXR sigmoid structure prior to eruption, and some others show no prominent SXR signature of any kind before or during eruption.

Sterling, Alphonse C.; Rose, M. Franklin (Technical Monitor)

2000-01-01

104

Sigmoid CME Source Regions at The Sun: Some Recent Results  

NASA Technical Reports Server (NTRS)

Identifying coronal mass ejection (CME) precursors in the solar corona would be an important step in space weather forecasting, as well as a vital key to understanding the physics of CMEs. Twisted magnetic field structures are suspected of being the source of at least some CMEs. These features can appear sigmoid (S or inverse-S) shaped in soft X-ray, (SXR) images. We review recent observations of these structures and their relation to CMEs. using SXR data from the Soft X-ray Telescope (SXT) on the Yohkoh satellite, and EUV data from the EUV Imaging Telescope (EIT) on the SOHO satellite. These observations indicate that the pre-eruption sigmoid patterns are more prominent in SXRs than in EUV, and that sigmoid precursors are present in over 50% of CMEs. These findings are important for CME research, and may potentially be a major component to space weather forecasting. So far, however, the studies have been subject to restrictions that will have to be relaxed before sigmoid morphology can be used as a reliable predictive too[. Moreover, some CMEs do not display a SXR sigmoid structure prior to eruption, and some others show no prominent SXR signature of any kind before or during eruption.

Sterling, Alphonse C.

2000-01-01

105

Homologous CME: a multispacecraft approach supported by simulations  

NASA Astrophysics Data System (ADS)

Using in situ and remote observations from multiple space crafts (STEREO, SDO and Venus Express) provides the opportunity to to study homologous CMEs. For example, on 7 August 2010, a halo CME originating from NOAA AR11093 was observed remotely by STEREO B. Seven days later this active region erupted again, and a halo CME was observed remotely by STEREO A on 14 August 2010. In this and in similar other examples, we show that multiple eruptions are associated with reverse S-shaped flux rope structures and display a number of typical large-scale features related to CMEs, including coronal dimmings and EUV waves. By combining remote sensing and in situ observations of the ejecta, we consider the structure and heliospheric evolution of these CMEs and their interplanetary counterparts. The work is complemented by a theoretical investigation where observed features are replicated and clarified by simulation. This work is part of the eHeroes project (www.eheroes.eu), funded by the European Commission, under the grant agreement eHeroes (project n° 284461)

Sanna, L.; Lapenta, G.; Steed, K.; Olshevsky, V.; Restante, A.

2012-12-01

106

CME Initiation Driven by Velocity-Shear Kinetic Reconnection Simulations  

NASA Astrophysics Data System (ADS)

In the standard model for coronal mass ejections (CME) and/or solar flares, the free energy for the event resides in the strongly sheared magnetic field of a filament channel. The pre-eruption force balance consists of an upward force due to the magnetic pressure of the sheared field countered by a downward tension due to overlying unsheared field. Magnetic reconnection is widely believed to be the mechanism that disrupts this force balance, leading to explosive eruption. For understanding CME/flare initiation, therefore, it is critical to model the onset of reconnection that is driven by the build-up of magnetic shear. In MHD simulations, the application of a magnetic-field shear is a trivial matter. However, kinetic effects are important in the diffusion region and thus, it is important to examine this process with PIC simulations as well. The implementation of such a driver in PIC methods is nontrivial, however, and indicates the necessity of a true multiscale model for such processes in the solar environment. The field must be sheared self-consistently and indirectly to prevent the generation of waves that destroy the desired system. In the work presented here, we discuss methods for applying a velocity shear perpendicular to the plane of reconnection in a system with open boundary conditions. This material is based upon work supported by the National Science Foundation under Award No. AGS-1331356.

Black, Carrie; Antiochos, Spiro K.; Karpen, Judith T.; DeVore, C. Richard; Germaschewski, Kai

2014-06-01

107

Effect on the Lunar Exosphere of a CME Passage  

NASA Technical Reports Server (NTRS)

It has long been recognized that solar wind bombardment onto exposed surfaces in the solar system will produce an energetic component to the exospheres about those bodies. Laboratory experiments have shown that the sputter yield can be noticeably increased in the case of a good insulating surface. It is now known that the solar wind composition is highly dependent on the origin of the particular plasma. Using the measured composition of the slow wind. fast wind. solar energetic particle (SEP) population. and coronal mass ejection (CME), broken down into its various components, we have estimated the total sputter yield for each type of solar wind. The heavy ion component, especially the He(++) component, greatly enhances the total sputter yield during times when the heavy ion population is enhanced, most notably during a coronal mass ejection. To simulate the etfect on the lunar exosphere of a CME passage past the Moon, we ran a Monte Carlo code for the species Na, K, Mg and Ca.

Killen, Roseamry M.; Hurley, Dana M.; Farrell, William M.; Sarantos, Menelaos

2011-01-01

108

Effect on the Lunar Exosphere of a CME Passage  

NASA Technical Reports Server (NTRS)

It has long been recognized that solar wind bombardment onto exposed surfaces in the solar system will produce an energetic component to the exospheres about those bodies. Laboratory experiments have shown that the sputter yield can be noticeably increased in the case of a good insulating surface. It is now known that the solar wind composition is highly dependent on the origin of the particular plasma. Using the measured composition of the slow wind, fast wind, solar energetic particle (SEP) population, and coronal mass ejection (CME), broken down into its various components, we have estimated the total sputter yield for each type of solar wind. The heavy ion component, especially the He++ component, greatly enhances the total sputter yield during times when the heavy ion population is enhanced, most notably during a coronal mass ejection. To simulate the effect on the lunar exosphere of a CME passage past the Moon, we ran a Monte Carlo code for the species Na, K, Mg and Ca.

Killen, Rosemary M.; Hurley, Dana M.; Farrell, William M.; Sarantos, Menelaos

2011-01-01

109

Effect of CME on Primary Care and OB/GYN Treatment of Breast Masses  

ERIC Educational Resources Information Center

Introduction: CME program planners are being asked to move beyond assessments of knowledge to assessing the impact of CME on practice and patient outcomes. Methods: We conducted a pre-post analysis of administrative data from 107 physicians, nurse practitioners (NPs), or physician's assistants (PAs) who attended one or two continuing medical…

Price, David W.; Xu, Stanley; McClure, David

2005-01-01

110

An empirical model for prediction of geomagnetic storms using initially observed CME parameters at the Sun  

Microsoft Academic Search

In this study, we discuss the general behaviors of geomagnetic storm strength associated with observed parameters of coronal mass ejection (CME) such as speed (V) and earthward direction (D) of CMEs as well as the longitude (L) and magnetic field orientation (M) of overlaying potential fields of the CME source region, and we develop an empirical model to predict geomagnetic

R.-S. Kim; K.-S. Cho; Y.-J. Moon; M. Dryer; J. Lee; Y. Yi; K.-H. Kim; H. Wang; Y.-D. Park; Yong Ha Kim

2010-01-01

111

Geoeffectiveness of the coronal mass ejection (CME) of April 4, 2000  

Microsoft Academic Search

As seen in SOHO\\/LASCO images a halo CME with a bright front began on April 04, 2000 at about 1632 UT. This appeared to be associated with C9 flare in AR 8933. With IPS observations at 103 MHz (these are recorded by an array radio telescope at Rajkot, India), we detected the effect of this CME at the line of

H. Vats; R. Jadhav; K. Iyer

2002-01-01

112

On radar cross-section of the Sun during earthward-directed CME  

Microsoft Academic Search

In order to design radar experiments for the study of the Sun, it is necessary to make some preliminary estimates. We report results of crude calculations of the solar radar cross section during the appearance of a geoeffective CME. For the calculations, we consider the CME to be a spherical expanding plasma shell with a constant mass moving towards the

Yu. I. Belov; S. M. Grach; P. Rodriguez; B. Thide; Yu. V. Tokarev

2003-01-01

113

Implications of CME Deflections on the Habitability of Planets Around M Dwarfs  

NASA Astrophysics Data System (ADS)

Solar coronal mass ejections (CMEs) are known to produce adverse space weather effects at Earth. These effects include geomagnetically induced currents and energetic particles accelerated by CME-driven shocks. Significant non-radial motions are observed for solar CMEs with the CME path deviating as much as 30 degrees within 20 solar radii. We have developed a model, Forecasting a CME's Altered Trajectory (ForeCAT), which predicts the deflected path of a CME according to the magnetic forces of the background solar wind. In Kay et al (2013), we show that these magnetic forces cause CMEs to deflect towards the region of minimum magnetic field strength. For the Sun, this magnetic minimum corresponds to the Heliospheric Current Sheet (HCS). We predict that the Earth is most likely to be impacted by a deflected CME when its orbit brings it near the HCS. M dwarfs can have magnetic field strengths several orders of magnitude larger than the Sun which will strongly affect CME deflections. We explore stellar CME deflections with ForeCAT. We present results for M4V star V374 Peg. We determine potential impacts caused by CME deflections for a planet located within the habitable zone of V374 Peg 20-40 solar radii). We discuss future extensions as including variations in solar cycle, capturing small structures such as active regions, and extensions for other M dwarf stars.

Kay, Christina; Opher, Merav

2014-06-01

114

Relation between CME Speed and Magnetic Helicity in Solar Source Regions  

NASA Astrophysics Data System (ADS)

Coronal mass ejections (CMEs) are thought to be powered by the free energy in the solar source regions. The magnetic helicity in the source regions is one of the indicators of this free energy. In order to see the relationship between the magnetic helicity of CME source regions and CME energy, we considered a set of 41 solar source regions (from solar cycle 23) from which CMEs erupted and ended up as magnetic clouds near Earth. Using EUV and magnetogram data from the Solar and Heliospheric Observatory (SOHO) mission, we determined the most probable linear force-free magnetic structure and its magnetic helicity for each CME source region. The magnetograms taken just prior to the CME eruption were used to compute the magnetic helicity. The CME speeds were obtained from the SOHO/LASCO CME catalog (http://cdaw.gsfc.nasa.gov). We found that the magnetic helicity is positively correlated with the speed of CMEs. This result suggests that the magnetic helicity of CME source regions maybe useful for predicting CME speed.

Jung, H.; Gopalswamy, N.; Akiyama, S.; Yashiro, S.; Xie, H.

2010-12-01

115

Promoting Free Online CME for Intimate Partner Violence: What Works at What Cost?  

ERIC Educational Resources Information Center

Introduction: There is a need to provide practicing physicians with training on the recognition and management of intimate partner violence (IPV). Online continuing medical education (CME) could help meet this need, but there is little information on the costs and effectiveness of promoting online CME to physicians. This lack of information may…

Harris, John M., Jr.; Novalis-Marine, Cheryl; Amend, Robert W.; Surprenant, Zita J.

2009-01-01

116

Academic podcasting: quality media delivery.  

PubMed

A video podcast of the CME-approved University of Utah Department of Biomedical Informatics seminar was created in order to address issues with streaming video quality, take advantage of popular web-based syndication methods, and make the files available for convenient, subscription-based download. An RSS feed, which is automatically generated, contains links to the media files and allows viewers to easily subscribe to the weekly seminars in a format that guarantees consistent video quality. PMID:17238744

Tripp, Jacob S; Duvall, Scott L; Cowan, Derek L; Kamauu, Aaron W C

2006-01-01

117

Tracking of Interplanetary CME/Shocks Using Type II Radio Observations  

NASA Astrophysics Data System (ADS)

Interplanetary Type II radio burst radiation results from the excitation of plasma waves in the ambient medium by shock waves driven by coronal mass ejections (CMEs). These radio emissions provide a means of remotely tracking CME/shocks. The aim of this work is to combine, by using WIND/WAVES and STEREO/SWAVES radio data, different techniques to estimate the speed evolution of CME/shocks associated with Type II radio bursts. Moreover, in order to illuminate the CME/shock propagation, it is included an analysis of coronographic and heliospheric images, in situ data, and an analytical model of CME/shock propagation, which provide complementary information on CME/shocks propagating through the entire Sun-Earth connected space.

Aguilar-Rodriguez, E.; Ontiveros-Hernandez, V.; Manuel-Hernandez, T.; Corona-Romero, P.; Gonzalez-Esparza, A.

2012-12-01

118

Transition of a traditional pharmacology course for dental students to an online delivery format: a pilot project.  

PubMed

The purpose of this report is to describe the rationale and subsequent transition of a pharmacology course for dental students from a traditional face-to-face lecture format to online delivery using a course management system (CMS). A dental school faculty member with dental and pharmacology degrees and a Ph.D. was asked to serve as course director and to develop and implement a nontraditional course using the Blackboard CMS technology, which houses asynchronous course content materials, study guides, and online resource materials. Respondus software was used to create, manage, and administer weekly online quizzes. A comprehensive midterm and final examination were conducted in a traditional face-to-face setting. A survey was used to capture student satisfaction with this self-directed introductory pharmacology course. Participants were second-year dental students (Classes of 2011 and 2012). There was a survey response rate of 91 percent (179/197). The Likert-style survey questions produced ordinal data from which the median and interquartile range were calculated. On a scale in which 1=Poor, 5=Excellent, the median evaluation for the instructor was 4 (IQR=1.5). On a global question that asked how students rate the course overall, the median score was 4 (IQR=1.0). Results show that a majority of students were positive about the online delivery of the introductory pharmacology course and for many students this was their first online course experience. Resistance to self-directed learning was a theme with those students who rated the course poorly. In a comparison of overall course grades from the previous year, student performance in this course was much stronger. As a result of student feedback seeking more interaction with the course director, it was determined that the next time the course is offered there will be additional opportunities for greater face-to-face time with the instructor. Ongoing evaluation will be important as new teaching technologies emerge and are adopted for teaching and learning. PMID:21546597

Gadbury-Amyot, Cynthia C; Brockman, William G

2011-05-01

119

Using multi-wavelength observations to constrain CME simulations  

NASA Astrophysics Data System (ADS)

The steady growth of computing power now provides the possibility to model coronal mass ejections (CMEs) at different levels of complexity. Present CME simulations range from relatively simple zero-beta calculations, which consider idealized configurations to isolate the basic physical mechanisms at work in CMEs, to semi-realistic "thermodynamic" MHD simulations of specific events that allow us to confront the model results directly with the observations. In this talk, we will discuss the respective benefits of these different approaches. As an example, we will consider the well-known sympathetic eruptions event on 2010, August 1, which our group has been modeling using various degrees of approximation. In particular, we will illustrate how we employed the observations (i) to set up the respective initial magnetic configurations and (ii) to validate the simulation results.

Torok, T.; Mikic, Z.; Titov, V. S.; Linker, J. A.; Downs, C.; Lionello, R.; Riley, P.

2012-12-01

120

Nozzle Driven Shocks in Post-CME Plasma  

NASA Astrophysics Data System (ADS)

Models of patchy reconnection allow for heating and acceleration of plasma along reconnected field lines but do not offer a mechanism for transport of energy and momentum across field lines. Here we present a simple 2D model in which a localized region of reconnected flux creates an apparent constriction in the surrounding layer of unreconnected field. The moving constriction acts as a de Laval nozzle and ultimately leads to shocks which can extend out to several times the diameter of the flux tube, altering the density and temperature of the plasma in that region. These findings have direct implications for observations in the solar corona, particularly in regard to such phenomena as wakes seen behind supra-arcade downflows and high temperatures in post-CME current sheets. This work was supported by a joint grant from the NSF and DOE.

Scott, Roger B.; Longcope, D. W.; McKenzie, D. E.

2012-05-01

121

CME Interaction with Coronal Holes and Their Interplanetary Consequences  

NASA Technical Reports Server (NTRS)

A significant number of interplanetary (IP) shocks (-17%) during cycle 23 were not followed by drivers. The number of such "driverless" shocks steadily increased with the solar cycle with 15%, 33%, and 52% occurring in the rise, maximum, and declining phase of the solar cycle. The solar sources of 15% of the driverless shocks were very close the central meridian of the Sun (within approx.15deg), which is quite unexpected. More interestingly, all the driverless shocks with their solar sources near the solar disk center occurred during the declining phase of solar cycle 23. When we investigated the coronal environment of the source regions of driverless shocks, we found that in each case there was at least one coronal hole nearby suggesting that the coronal holes might have deflected the associated coronal mass ejections (CMEs) away from the Sun-Earth line. The presence of abundant low-latitude coronal holes during the declining phase further explains why CMEs originating close to the disk center mimic the limb CMEs, which normally lead to driverless shocks due to purely geometrical reasons. We also examined the solar source regions of shocks with drivers. For these, the coronal holes were located such that they either had no influence on the CME trajectories. or they deflected the CMEs towards the Sun-Earth line. We also obtained the open magnetic field distribution on the Sun by performing a potential field source surface extrapolation to the corona. It was found that the CMEs generally move away from the open magnetic field regions. The CME-coronal hole interaction must be widespread in the declining phase, and may have a significant impact on the geoeffectiveness of CMEs.

Gopalswamy, N.; Makela, P.; Xie, H.; Akiyama, S.; Yashiro, S.

2008-01-01

122

A High-Speed Erupting-Prominence CME: A Bridge Between Types  

NASA Astrophysics Data System (ADS)

Several studies have indicated that there may be two distinct types of coronal mass ejections (CMEs); a high-velocity bright energetic type associated with flares, and a smaller slower less impressive type associated with erupting prominences. How valid is this distinction? We analyze a CME combining attributes of both types, a high-velocity bright CME associated with an erupting prominence. A study of this event and several others allows us to argue that the apparent differences separating the two types may be an observational effect. Our results are consistent with a single CME process for both flare-associated and filament-associated CMEs. This process consists of three stages. The initial stage is brought about by the emergence of new magnetic flux, which interacts with the pre-existing magnetic configuration and results in a slow rise of the magnetic structure, which later becomes the CME. The second stage is a fast reconnection phase with flaring and a sudden increase of the rise velocity of the magnetic structure. It also includes a rapidly increasing CME acceleration followed by a rapidly falling acceleration. The third stage or CME propagation stage shows only slow changes in the acceleration and finally the velocity becomes constant. LASCO observes only the third stage. The differences found between observed flare-associated and prominence-associated CME velocity behavior appear to be primarily due to the relative heights in the corona at which the erupting structures form.

Feynman, Joan; Ruzmaikin, Alexander

2004-02-01

123

A High-Speed Erupting Prominence CME:A Bridge Between Types  

NASA Astrophysics Data System (ADS)

Several studies have indicated that there may be two distinct types of Coronal Mass Ejections (CMEs): a high velocity bright energetic type associated with flares, and a smaller slower less impressive type associated with erupting prominences. How valid is this distinction? We analyze a CME combining attributes of both types, a high velocity bright CME associated with an erupting prominence. A study of this event and several others allows us to argue that the apparent differences separating the two types may be an observational effect. Our results are consistent with a single CME process for both flare associated and filament associated CMEs. This process consists of three stages. The initial stage is brought about by the emergence of new magnetic flux, which interacts with the pre-existing magnetic configuration and results in a slow rise of the magnetic structure, which later becomes the CME. The second stage is a fast reconnection phase with flaring and a sudden increase of the rise velocity of the magnetic structure. It also includes a rapidly increasing CME acceleration followed by a rapidly falling acceleration. The third stage or CME propagation stage shows only slow changes in the acceleration and finally the velocity becomes constant. LASCO observes only the third stage. The differences found between observed flare-associated and prominence-associated CME velocity behavior appears to be primarily due to the relative heights in the corona at which the erupting structures form.

Feynman, J.; Ruzmaikin, A.

2004-05-01

124

Analysis of Coronal Mass Ejection (CME) Ion Charge States Detected with ACE  

NASA Astrophysics Data System (ADS)

We describe a new modeling approach to develop a more quantitative understanding of the charge state distributions of the ions of various elements detected in situ during halo CME events by the Advanced Composition Explorer (ACE) satellite. Using a model CME hydrodynamic evolution based on observations of CMEs propagating in the plane of the sky and on theoretical models, we integrate time dependent equations for the ionization balance of various elements to compare with ACE data. We find that plasma in the CME "core" typically requires further heating following filament eruption, with thermal energy input similar to the kinetic energy input. This extra heating is presumably the result of post eruptive reconnection. Plasma corresponding to the CME "cavity" is usually not further ionized, since whether heated or not, the low density gives freeze-in close the the Sun. The current analysis is limited by ambiguities in the underlying model CME evolution. Such methods are likely to reach their full potential when applied to data to be acquired by STEREO when at optimum separation. CME evolution observed with one spacecraft may be used to intepret CME charge states detected by the other. This work has been supported by the NASA LWS and NSF SHINE Programs.

Laming, J. M.; Rakowski, C. E.; Lepri, S. T.

2007-05-01

125

The Width of a CME and the Source of the Driving Magnetic Explosion  

NASA Technical Reports Server (NTRS)

We show that the strength of the magnetic field in the area covered by the flare arcade following a CME-producing ejective solar eruption can be estimated from the final angular width of the CME in the outer corona and the final angular width of the flare arcade. We assume (1) the flux-rope plasmoid ejected from the flare site becomes the interior of the CME plasmoid, (2) in the outer corona the CME is roughly a "spherical plasmoid with legs" shaped like a light bulb, and (3) beyond some height in or below the outer corona the CME plasmoid is in lateral pressure balance with the surrounding magnetic field. The strength of the nearly radial magnetic field in the outer corona is estimated from the radial component of the interplanetary magnetic field measured by Ulysses. We apply this model to three well-observed CMEs that exploded from flare regions of extremely different size and magnetic setting. In each event, the estimated source-region field strength is appropriate for the magnetic setting of the flare. This agreement indicates via the model that CMEs (1) are propelled by the magnetic field of the CME plasmoid pushing against the surrounding magnetic field, and (2) can explode from flare regions that are laterally far offset from the radial path of the CME in the outer corona.

Moore, R. L.; Sterling, A. C.; Suess, S. T.

2007-01-01

126

Relationship between a CME-driven shock and a coronal metric type II burst  

NASA Astrophysics Data System (ADS)

It has been a long-standing controversy whether coronal metric type II bursts are generated by CME-driven shocks or flare blast waves. Using unprecedented high-cadence observations from STEREO/SECCHI, we investigate the relationship between a metric type II event and a shock driven by the 2007 December 31 CME. The CME occurs at the east limb and its evolution is observed from about 1.1 to several tens of solar radii. The existence of the CME-driven shock is indicated by the deflection of coronal structures before the CME impinges on them, the best evidence for shocks in imaging observations. The earliest deflection of distant coronal structures occurs at 00:51:22 UT, about 2.6 min before the metric type II onset. The CME- driven shock emerges from the corona and produces a break point in the streamer north of the CME, which allows us to follow the shock propagation in imaging observations for the first time. We also have a continuous frequency coverage of the radio dynamic spectrum by combining observations from STEREO/SWAVES, BIRS and Learmonth, which successfully establishes the connection between the metric and decametric-hectometric (DH) type II bursts. The CME speed is about 600 km/s at the time of the metric type II onset, larger than the Alfven speed 420 - 490 km/s determined from the band splitting of the metric type II burst. The shock height-time curve determined from the metric and DH type II bands is consistent with the shock propagation obtained from the streamer deflection. These results provide unambiguous evidence that the metric type II burst is caused by the CME-driven shock. Implications are also discussed for particle acceleration and space weather forecasting.

Liu, Y.; Luhmann, J.; Bale, S.; Lin, R.

2008-12-01

127

Effects of the 5 October 1996 CME at 4.4 AU: Ulysses observations  

SciTech Connect

The authors present observations from Ulysses associated with a large coronal mass ejection (CME) that lifted off the west limb of the Sun on 5 October, 1996. The study focuses on the effects of the interplanetary counterpart of the CME on the energetic particle populations at the location of Ulysses, in particular the effect on the sequence of corotating enhancements that had been observed prior to its arrival. They conclude that, despite its large spatial extent, the CME caused no permanent deformation of the heliospheric current sheet.

Marsden, R.G.; Desai, M.I.; Sanderson, T.R. [Estec, Noordwijk (Netherlands). Space Science Dept. of ESA; Forsyth, R.J. [Imperial Coll., London (United Kingdom); Gosling, J.T. [Los Alamos National Lab., NM (United States)

1997-09-01

128

Royal College's CME initiative focuses on lifelong, practice-integrated learning  

PubMed Central

An innovative continuing medical education (CME) initiative of the Royal College of Physicians and Surgeons of Canada is gaining worldwide attention. Emphasizing lifelong learning, the Maintenance of Competence Program gives college fellows an efficient, effective way to determine their educational needs, manage their CME activities and hone their clinical practice habits. More than half of college fellows are expected to join it by this summer. A spokesperson predicts that in 5 years bodies such as licensing authorities and hospital-privileges committees will require evidence of participation in a structured CME plan. Imagesp967-a

Berube, Brian

1995-01-01

129

The influence of collagen and hyaluronan matrices on the delivery and bioactivity of bone morphogenetic protein-2 and ectopic bone formation.  

PubMed

Bone morphogenetic protein-2 (BMP-2) is known to enhance fracture healing when delivered via a bovine collagen sponge. However, collagen rapidly releases BMP-2 with a high burst phase that is followed by a low sustained phase. As a result, supra-physiological doses of BMP-2 are often required to successfully treat bone defects. High BMP-2 dosing can introduce serious side effects that include edema, bone overgrowth, cyst-like bone formation and significant inflammation. As the release behavior of BMP-2 carriers significantly affects the efficacy of fracture healing, we sought to compare the influence of two BMP-2 delivery matrices with contrasting release profiles on BMP-2 bioactivity and ectopic bone formation. We compared a thiol-modified hyaluronan (Glycosil™) hydrogel that exhibits a low burst followed by a sustained release of BMP-2 to a collagen sponge for the delivery of three different doses of BMP-2, the bioactivities of released BMP-2 and ectopic bone formation. Analysis of bone formation by micro-computed tomography revealed that low burst followed by sustained release of BMP-2 from a hyaluronan hydrogel induced up to 456% more bone compared to a BMP-2 dose-matched collagen sponge that has a high burst and sustained release. This study demonstrates that BMP-2 released with a low burst followed by a sustained release of BMP-2 is more desirable for bone formation. This highlights the therapeutic potential of hydrogels, particularly hyaluronan-based, for the delivery of BMP-2 for the treatment of bone defects and may help abrogate the adverse clinical effects associated with high dose growth factor use. PMID:23871940

Bhakta, Gajadhar; Lim, Zophia X H; Rai, Bina; Lin, Tingxuan; Hui, James H; Prestwich, Glenn D; van Wijnen, Andre J; Nurcombe, Victor; Cool, Simon M

2013-11-01

130

Radio Tracking of a White-Light CME from Solar Corona to Interplanetary Medium  

NASA Technical Reports Server (NTRS)

We analyze the radio emissions associated with a flare/CME event on the sun. For this solar event there were type II radio emissions observed in both the metric and decametric to kilometric wavelength regimes. By comparing the dynamics of the CME with that implied by the frequencies and frequency-drift rates of the type II radio emissions, it is concluded that only the decametric/kilometric type II radio emissions are associated with the CME. We provide the first direct one-to-one comparison between a CME and the associated type II radio emissions. The dynamics implied by the metric type II radio emissions suggest a distinct coronal shock, associated with the flare, which only produces radio emissions in the low corona.

Reiner, M. J.; Kaiser, Michael L.; Plunkett, S. P.; Prestage, N. P.

1999-01-01

131

A CME-Driven Solar Wind Disturbance Observed at both Low and High Heliographic Latitudes  

NASA Technical Reports Server (NTRS)

A solar wind disturbance produced by a fast coronal mass ejection, CME, that departed from the Sun on February 20, 1994 was observed in the ecliptic plane at 1 AU by IMP 8 and at high heliographic latitudes at 3.53 AU by Ulysses. In the ecliptic the disturbance included a strong forward shock but no reverse shock, while at high latitudes the disturbance was bounded by a relatively weak forward-reverse shock pair. It is clear that the disturbance in the ecliptic plane was driven primarily by the relative speed between the CME and a slower ambient solar wind ahead, whereas at higher latitudes the disturbance was driven by expansion of the CME. The combined IMP 8 and Ulysses observations thus provide a graphic illustration of how a single fast CME can produce very different types of solar wind disturbances at low and high heliographic latitudes. Simple numerical simulations help explain observed differences at the two spacecraft.

Gosling, J. T.; McComas, D. J.; Phillips, J. L.; Pizzo, V. J.; Goldstein, B. E.; Forsyth, R. J.; Lepping, R. P.

1995-01-01

132

Geometric Localization and Polarimetric Localization: Space Weather Tools to Calculate CME Propagation Characteristics  

NASA Astrophysics Data System (ADS)

The geometric localization technique [Pizzo and Biesecker, 2004] utilizes a series of lines of sight from two space-based coronagraphs to determine gross propagation characteristics of coronal mass ejections (CMEs) in three-dimensional space. The polarimetric localization technique [Moran and Davila, 2004] uses the percent polarization observed by a single coronagraph to obtain a three-dimensional reconstruction of a CME. Both techniques can be used in near-real-time within an operational space weather forecast center. When these two independent techniques are used in conjunction with each other to analyze STEREO/Secchi/COR2 beacon data, they can provide significant constraints on the three-dimensional location and velocity, including speed and direction, for any Earth-directed CME. Here, we employ these techniques to the CME of 31 December 2007 and compare results on the speed and direction of propagation for this CME.

Pizzo, V. J.; de Koning, C. A.

2008-12-01

133

CME, Physicians, and Pavlov: Can We Change What Happens When Industry Rings the Bell?  

PubMed Central

Purpose To show how physicians’ conditioned response to “keeping up” has helped industry’s opportunistic funding of continuing medical education (CME) and to propose ways to counter the conditioned response to the benefit of patients and the public. Methods Review of the literature and commentary on it. Results The pharmaceutical and device industries (hereafter referred to as industry) have a long history of bribing physicians to prescribe and use their products. Increasing pressure from Congress and the public has been brought to bear on industry gifting. This pressure, coinciding with increasing financial problems for the providers of CME, provided industry with reason and opportunity to expand its role in the financing of CME. Industry’s incentive to make its CME funding appear to be an arm’s-length transaction has spawned medical education service supplier (MESS) companies. Industry makes “unrestricted grants” to the MESS, and the MESS puts on the CME program. Helped by these CME programs, industry is able to subtly “buy” physicians one at a time, so that under the cover of “education” they and their academic institutions and medical organizations lose sight of being CME pawns in industry’s sole objective: profit. Conclusions Despite a vast literature showing how physician integrity is easy prey to industry, the medical profession continues to allow industry to have a detrimental influence on the practice of medicine and on physician respectability. It will take resolute action to change the medical profession’s conditioned response to industry’s CME bell and its negative effect on patients and the public.

Lichter, Paul R.

2008-01-01

134

Observational Signatures of Ion Acceleration Near CME-Driven Interplanetary Shocks  

Microsoft Academic Search

Coronal Mass Ejection- or CME-driven interplanetary (IP) shocks are responsible for causing the so-called energetic storm particle (ESP) events observed at Earth. However, despite recent observational and theoretical advances, many important questions regarding such CME-associated particle events remain unanswered. This is because ESP events occur due to a confluence of numerous poorly understood physical effects all of whose contributions can

M. I. Desai; M. A. Dayeh; M. A. Lee; C. W. Smith; G. M. Mason; J. C. Kasper

2010-01-01

135

The SCEC Community Modeling Environment(SCEC\\/CME): A Collaboratory for Seismic Hazard Analysis  

Microsoft Academic Search

The SCEC Community Modeling Environment (SCEC\\/CME) Project is an NSF-supported Geosciences\\/IT partnership that is actively developing an advanced information infrastructure for system-level earthquake science in Southern California. This partnership includes SCEC, USC's Information Sciences Institute (ISI), the San Diego Supercomputer Center (SDSC), the Incorporated Institutions for Research in Seismology (IRIS), and the U.S. Geological Survey. The goal of the SCEC\\/CME

P. J. Maechling; T. H. Jordan; J. B. Minster; R. Moore; C. Kesselman

2005-01-01

136

CME-associated Radio Bursts from Satellite Observations  

NASA Astrophysics Data System (ADS)

Coronal mass ejections (CMEs) are closely associated with various types of radio bursts from the Sun. All radio bursts are due to nonthermal electrons, which are accelerated during the eruption of CMEs. Radio bursts at frequencies below about 15 MHz are of particular interest because they are associated with energetic CMEs that contribute to severe space weather. The low-frequency bursts need to be observed primarily from space because of the ionospheric cutoff. The main CME-related radio bursts are associated are: type III bursts due to accelerated electrons propagating along open magnetic field lines, type II bursts due to electrons accelerated in shocks, and type IV bursts due to electrons trapped in post-eruption arcades behind CMEs. This paper presents a summary of results obtained during solar cycle 23 primarily using the white-light coronagraphic observations from the Solar Heliospheric Observatory (SOHO) and the WAVES experiment on board Wind. Particular emphasis will be placed on what we can learn about particle acceleration in the coronal and interplanetary medium by analyzing the CMEs and the associated radio bursts.

Gopalswamy, Nat

2012-05-01

137

X-ray and EUV Observations of CME Eruption Onset  

NASA Technical Reports Server (NTRS)

Why Coronal Mass Ejections (CMEs) erupt is a major outstanding puzzle of solar physics. Signatures observable at the earliest stages of eruption onset may hold precious clues about the onset mechanism. We present observations from SOHO/EIT and from TRACE in EUV, and from Yohkoh/SXT in soft X-rays of the pre-eruption and eruption phases of CME expulsion, along with the eruption's magnetic setting found from SOHO/MDI magnetograms. Most of our events involve clearly-observable filament eruptions and multiple neutral lines, and we use the magnetic settings and motions of the filaments to help infer the geometry and behavior of the associated erupting magnetic fields. Pre-eruption and early-eruption signatures include a relatively slow filament rise prior to eruption, and intensity "dimmings" and brightenings, both in the immediate neighborhood of the "core" (location of greatest magnetic shear) of the erupting fields and at locations remote from the core. These signatures and their relative timings place observational constraints on eruption mechanisms; our recent work has focused on implications for the so-called "tether cutting" and "breakout" models, but the same observational constraints are applicable to any model.

Sterling, A. C.

2004-01-01

138

CME Eruption Onset Observations from EIT and SXT  

NASA Technical Reports Server (NTRS)

Why CMEs erupt is a major outstanding puzzle of solar physics. Signatures observable at the earliest stages of eruption onset may hold precious clues about the onset mechanism. We present observations in EUV from SOHO/EIT and in soft X-rays from Yohkoh/SXT of the re-eruption and eruption phases of CME expulsion, along with the eruption's magnetic setting found from SOHO/MDI magnetograms. Most of our events involve clearly-observable filament eruptions and multiple neutral lines, and we use the magnetic settings and motions of the filaments to help infer the geometry and behavior of the associated erupting magnetic fields. Pre-eruption and early-eruption signatures include a relatively slow filament rise prior to eruption, and intensity "dimmings" and brightenings, both in the immediate neighborhood of the "core" (location of greatest magnetic shear) of the erupting fields and at locations remote from the core. These signatures and their relative timings place observational constraints on eruption mechanisms; our recent work has focused on implications for the so-called "tether cutting" and "breakout" models, but the same observational constraints are applicable to any model.

Sterling, A. C.

2004-01-01

139

Kinematic Treatment of CME Evolution in the Solar Wind  

NASA Technical Reports Server (NTRS)

We present a kinematic study of the evolution of coronal mass ejections (CMEs) in the solar wind. Specifically, we consider the effects of: (1) spherical expansion; and (2) uniform expansion due to pressure gradients between the Interplanetary CME (ICME) and the ambient solar wind. We compare these results with an MHD model, which allows us to isolate these effects from the combined kinematic and dynamical effects, which are included in MHD models. They also provide compelling evidence that the fundamental cross section of so-called "force-free" flux ropes (or magnetic clouds) is neither circular or elliptical, but rather a convex-outward, "pancake" shape. We apply a force-free fitting to the magnetic vectors from the MHD simulation to assess how the distortion of the flux rope affects the fitting. In spite of these limitations, force-free fittings, which are straightforward to apply, do provide an important description of a number of parameters, including the radial dimension, orientation and chirality of the ICME.

Riley, Pete; Crooker, N. U.

2004-01-01

140

CME-Associated Radio Bursts from Satellite Observations  

NASA Technical Reports Server (NTRS)

Coronal mass ejections (CMEs) are closely associated with various types of radio bursts from the Sun. All radio bursts are due to nonthermal electrons, which are accelerated during the eruption of CMEs. Radio bursts at frequencies below about 15 MHz are of particular interest because they are associated with energetic CMEs that contribute to severe space weather. The low-frequency bursts need to be observed primarily from space because of the ionospheric cutoff. The main CME-related radio bursts are associated are: type III bursts due to accelerated electrons propagating along open magnetic field lines, type II bursts due to electrons accelerated in shocks, and type IV bursts due to electrons trapped in post-eruption arcades behind CMEs. This paper presents a summary of results obtained during solar cycle 23 primarily using the white-light coronagraphic observations from the Solar Heliospheric Observatory (SOHO) and the WAVES experiment on board Wind. Particular emphasis will be placed on what we can learn about particle acceleration in the coronal and interplanetary medium by analyzing the CMEs and the associated radio bursts.

Gopalswamy, Nat

2012-01-01

141

Correlations Between EUV Coronal Spectral Line Dimming and CME Kinetics  

NASA Astrophysics Data System (ADS)

Coronal dimming in several spectral lines of the extreme ultraviolet (EUV) during and after flares may be indicative of the kinetics of coronal mass ejections (CMEs). Data from the EUV Variability Experiment (EVE) onboard the Solar Dynamics Observatory (SDO) are used to characterize the coronal dimming in several of the cooler corona emission lines available (e.g. Fe IX through Fe XII in the 17-20 nm range). Data from the Large Angle and Spectrometric Coronagraph Experiment (LASCO) onboard the Solar and Heliospheric Observatory (SOHO) and the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) coronagraphs onboard the twin Solar TErrestrial RElations Observatory (STEREO) spacecraft are used for identifying CMEs and deriving their velocities. These coronagraph data and also in-situ data from the Advanced Composition Explorer (ACE) are used for estimating the CME mass. Using these data sets, correlations are drawn between EUV emissions and their time variation during coronal dimming and the mass and velocity of coronal mass ejections.

Mason, J. P.; Woods, T. N.; Caspi, A.

2012-12-01

142

The Relationship Between Solar X-Ray Flux and Coronal Mass Ejection (CME) Energy  

NASA Astrophysics Data System (ADS)

Solar flares and their associated CMEs are an integral part of solar weather that can have profound effects on Earth's atmosphere. The charged particles emitted by strong CMEs and strong x-ray fluxes produced by solar flares can cause damage to satellites, disrupt radio and GPS signals, and strain power grids. It is critical to understand how solar flare intensity influences the magnitude of CMEs so as to minimize and prevent these consequential negative effects. This study investigated the hypothesis that solar x-ray flux has a direct correlation to CME energy. Total daily x-ray flux was correlated with CME energy for the years 2000-2012. X-ray flux data consisted of background and solar flare flux obtained from the Geostationary Operational Environmental Satellites (GOES). CME energy was obtained by squaring the 2nd-order speed at 20 Rs (solar radii) and summing these squared values for each day of each year. CME speed data was obtained from the NASA Large Angle and Spectrometric Coronagraph (LASCO) located on the Solar and Heliospheric Observatory satellite (SOHO). Results indicate significant correlations between solar x-ray flux and CME energy for the various years. Other factors that influence CME energy were also investigated.

Hirschberger, M.; Damas, M. C.; O'Connell, M.; Mezzafonte, D.; Marchese, A.; Carbone, A.; Chen, K.; Marchese, P.

2013-12-01

143

Relation between Magnetic Helicity and CME Speed in Source Active Regions  

NASA Astrophysics Data System (ADS)

We report on a study linking the speed of coronal mass ejections (CMEs) to the magnetic helicity in the source active regions. The motivation comes from the fact that the CME speed may depend on the active region free magnetic energy, which in turn may be represented by the helicity, a proxy for the nonpotentiality. We selected a set of active regions from solar cycle 23, measured their helicity, and identified CMEs from the CME catalog (http://cdaw.gsfc.nasa.gov). Using EUV and magnetogram data from the Solar and Heliospheric Observatory (SOHO) mission, we measured the coronal helicity content before CME eruptions. We extrapolated the photospheric magnetic field to the corona to obtain the coronal helicity that fits a EUV image before each CME eruption. The CME speeds used here corresponds to the average speed within the SOHO coronagraphic field of view. We found that magnetic helicity is positively correlated with the speed of CME. We cross-checked the helicity values using the principle of magnetic helicity conservation connecting helicity obtained from the Local Correlation Tracking (LCT) method, the helicity of the associated magnetic clouds and the coronal helicity.

Jung, H.; Gopalswamy, N.; Akiyama, S.; Yashiro, S.

2009-12-01

144

On the identification of time interval threshold in the twin-CME scenario  

NASA Astrophysics Data System (ADS)

Recently it has been suggested that the "twin-CME" scenario may be a very effective mechanism in causing extreme solar energetic particle (SEP) events and, in particular, ground level enhancement (GLE) events. Ding et al. (2013) performed a statistical examination of the twin-CME scenario with a total of 126 fast and wide western coronal mass ejections (CMEs). They found that CMEs having a preceding CME with a speed > 300 km/s within 9 h from the same active region have larger probability of leading to large SEP events than CMEs that do not have preceding CMEs. The choice of 9 h being the time lag ? between the preceding CME and the main CME was based on some crude estimates of the decay time of the turbulence downstream of the shock driven by the preceding CME. In this work, we examine this choice. For the 126 fast wide CMEs examined in, we vary the time lag ? from 1 h to 24 h with an increment of 1 h. By considering three quantities whose values depend on the choice of this time lag ?, we show that the choice of 13 h for ? is more appropriate. Our study confirms our earlier result that twin CMEs are more likely to lead to large SEP events than single fast CMEs. The results shown here are of great relevance to space weather studies.

Ding, Liu-Guan; Li, Gang; Dong, Li-Hua; Jiang, Yong; Jian, Yi; Gu, Bin

2014-03-01

145

Conducting a University Career and Technical Education Degree Program through Multiple Technology Delivery Formats: A Working Model.  

ERIC Educational Resources Information Center

The Department of Industrial Technology Education (ITE) at Indiana State University offers approximately 20 courses per semester, split equally between undergraduate and graduate courses. Although all classes are offered on campus, almost half of the ITE courses are also taught using these three alternative simultaneous delivery methods: (1) for…

Zirkle, Chris

146

Dual growth factor delivery and controlled scaffold degradation enhance in vivo bone formation by transplanted bone marrow stromal cells  

Microsoft Academic Search

Supraphysiological concentrations of exogenous growth factors are typically required to obtain bone regeneration, and it is unclear why lower levels are not effective. We hypothesized that delivery of bone progenitor cells along with appropriate combinations of growth factors and scaffold characteristics would allow physiological doses of proteins to be used for therapeutic bone regeneration. We tested this hypothesis by measuring

Craig A. Simmons; Eben Alsberg; Susan Hsiong; Woo J. Kim; David J. Mooneya

2004-01-01

147

Stereoscopic observations of the effects of a halo CME on the solar coronal structure  

NASA Astrophysics Data System (ADS)

We investigated the substantial restructuring of the outer solar corona in the aftermath of the halo CME that occurred on 9 March 2012. To perform our analysis, we used SOHO/LASCO, STEREO/COR1 and SDO/AIA data, which provide observations from different viewpoints. In particular, we applied the polarization ratio technique to the COR1 calibrated images to derive the three-dimensional structure of the CME and determine its direction and speed of propagation. We also estimated the CME mass from a sequence of four observations of the event and obtained values of up to 2.2 × 1016 g. The COR1 images show a brightness decrease in the coronal sector where the CME propagates. We verified that this intensity reduction is due to a plasma depletion. Moreover, the combined analysis performed by the two STEREO satellites allowed us to deduce that a preexisting streamer is located along the propagation direction of the CME and disappears after the passage of the event. The coronal mass loss associated with the plasma depletion is much lower than the mass expelled from the Sun in the COR1-B data. Conversely, the COR1-A obsevations allowed us to infer that the mass of the streamer carried away from the outer corona corresponds to about half of the CME mass. The results highlight the importance of stereoscopic observations in the study of corona restructuring in the aftermath of a CME event. The movie associated with Fig. 3 is available in electronic form at http://www.aanda.org

Dolei, S.; Romano, P.; Spadaro, D.; Ventura, R.

2014-07-01

148

Medical Problems Referred to a Care of the Elderly Physician: Insight for Future Geriatrics CME  

PubMed Central

Purpose Family physicians provide the majority of elderly patient care in Canada. Many experience significant challenges in serving this cohort. This study aimed to examine the medical problems of patients referred to a care of the elderly physician, to better understand the geriatric continuing medical education (CME) needs of family doctors. Methods A retrospective chart review of patients assessed at an urban outpatient seniors’ clinic between 2003 and 2008 was conducted. Data from 104 charts were analyzed and survey follow-up with 28 of the referring family physicians was undertaken. Main outcomes include the type and frequency of medical problems actually referred to a care of the elderly physician. Clarification of future geriatric CME topics of need was also assessed. Results Preventive care issues were addressed with 67 patients. Twenty-four required discussion of advance directives. The most common medical problems encountered were osteoarthritis (42), hypertension (34), osteoporosis (32), and depression or anxiety (23). Other common problems encountered that have not been highly cited as being a target of CME included musculoskeletal and joint pain (41), diabetes (23), neck and back pain (20), obesity (11), insomnia (11), and neuropathic, fibromyalgia and “leg cramps” pain (10). The referring family physicians surveyed agreed that these were topics of need for future CME. Conclusions The findings support geriatric CME for the common medical problems encountered. Chronic pain, diabetes, obesity and insomnia continue to be important unresolved issues previously unacknowledged by physicians as CME topics of need. Future CME focusing more on process of geriatric care may also be relevant.

Lam, Robert; Gallinaro, Anna; Adleman, Jenna

2013-01-01

149

Forecast of geomagnetic storms using CME parameters and the WSA-ENLIL model  

NASA Astrophysics Data System (ADS)

Intense geomagnetic storms are caused by coronal mass ejections (CMEs) from the Sun and their forecast is quite important in protecting space- and ground-based technological systems. The onset and strength of geomagnetic storms depend on the kinematic and magnetic properties of CMEs. Current forecast techniques mostly use solar wind in-situ measurements that provide only a short lead time. On the other hand, techniques using CME observations near the Sun have the potential to provide 1-3 days of lead time before the storm occurs. Therefore, one of the challenging issues is to forecast interplanetary magnetic field (IMF) southward components and hence geomagnetic storm strength with a lead-time on the order of 1-3 days. We are going to answer the following three questions: (1) when does a CME arrive at the Earth? (2) what is the probability that a CME can induce a geomagnetic storm? and (3) how strong is the storm? To address the first question, we forecast the arrival time and other physical parameters of CMEs at the Earth using the WSA-ENLIL model with three CME cone types. The second question is answered by examining the geoeffective and non-geoeffective CMEs depending on CME observations (speed, source location, earthward direction, magnetic field orientation, and cone-model output). The third question is addressed by examining the relationship between CME parameters and geomagnetic indices (or IMF southward component). The forecast method will be developed with a three-stage approach, which will make a prediction within four hours after the solar coronagraph data become available. We expect that this study will enable us to forecast the onset and strength of a geomagnetic storm a few days in advance using only CME parameters and the physics-based models.

Moon, Y.; Lee, J.; Jang, S.; Na, H.; Lee, J.

2013-12-01

150

The CORIMP CME Catalogue: Automatically Detecting and Tracking CMEs in Coronagraph Data  

NASA Astrophysics Data System (ADS)

Studying CMEs in coronagraph data can be challenging due to their diffuse structure and transient nature, and user-specific biases may be introduced through visual inspection of the images. The large amount of data available from the SOHO and STEREO missions also makes manual cataloguing of CMEs tedious, and so a robust method of detection and analysis is required. This has led to the development of automated CME detection and cataloguing packages such as CACTus, SEEDS and ARTEMIS. Here we present the development of the CORIMP (coronal image processing) Catalogue: a new, automated, multiscale, CME detection and tracking catalogue, that overcomes many of the drawbacks of current catalogues. It works by first employing a dynamic CME separation technique to remove the static background, and then characterizing CME structure via a multiscale edge-detection algorithm. The detections are chained through time to determine the CME kinematics and morphological changes as it propagates across the plane-of-sky. The effectiveness of the method is demonstrated by its application to a selection of SOHO/LASCO and STEREO/SECCHI images, as well as to synthetic coronagraph images created from a model corona with a variety of CMEs. These algorithms are being applied to the whole LASCO and SECCHI datasets, and a CORIMP catalogue of results will soon be available to the community.

Byrne, Jason; Morgan, H.; Habbal, S. R.

2012-05-01

151

Crystal structure of the Campylobacter jejuni CmeC outer membrane channel.  

PubMed

As one of the world's most prevalent enteric pathogens, Campylobacter jejuni is a major causative agent of human enterocolitis and is responsible for more than 400 million cases of diarrhea each year. The impact of this pathogen on children is of particular significance. Campylobacter has developed resistance to many antimicrobial agents via multidrug efflux machinery. The CmeABC tripartite multidrug efflux pump, belonging to the resistance-nodulation-cell division (RND) superfamily, plays a major role in drug resistant phenotypes of C. jejuni. This efflux complex spans the entire cell envelop of C. jejuni and mediates resistance to various antibiotics and toxic compounds. We here report the crystal structure of C. jejuni CmeC, the outer membrane component of the CmeABC tripartite multidrug efflux system. The structure reveals a possible mechanism for substrate export. PMID:24753291

Su, Chih-Chia; Radhakrishnan, Abhijith; Kumar, Nitin; Long, Feng; Bolla, Jani Reddy; Lei, Hsiang-Ting; Delmar, Jared A; Do, Sylvia V; Chou, Tsung-Han; Rajashankar, Kanagalaghatta R; Zhang, Qijing; Yu, Edward W

2014-07-01

152

Multi-wavelength study of a CME-driven shock at 4.1 solar radii  

NASA Astrophysics Data System (ADS)

We report on the analysis of a peculiar fast CME-driven shock associated to the eruption of March 22, 2002. The event was observed by the SOHO/UVCS instrument at 4.1 solar radii, with the spectrometer slit placed in correspondence of the flank of the expanding CME. Signatures of a strong MHD shock are observed in radio data (where a type-II radio burst was observed), white light SOHO/LASCO images (where a spherical density gradient located above the expanding CME front was observed) and in SOHO/UVCS spectra (where strong line broadenings are observed). UVCS, LASCO and radio data have been coupled to estimate not only the shock compression ratio and the pre-and post-shock plasma temperatures, but also, by applying the Rankine-Hugoniot equations for the general case of an oblique shock, the strength of the involved coronal magnetic fields.

Bemporad, Alessandro; Mancuso, Salvatore

153

Triangulation of CME Source Region Locations on the Sun and Dependence on Spacecraft Observation Angles  

NASA Astrophysics Data System (ADS)

STEREO-A, STEREO-B, and LASCO/SOHO observe coronal mass ejections (CMEs) from three different vantage points. On the basis of the radial plane-of-sky (POS) measurements of a CME in these three projection planes, the CME source region (SR) location was determined using the triangulation method of Temmeretal2009. As this triangulation method needs distance-time measurements in one POS as reference input, the determined SR varies with the change of the reference system. In the present study we vary the reference system, which shows the dependence of the resulting SR location of a CME on the spacecraft observation angles, and also reveals the limitation of the radial POS measurements.

Preiss, S.; Temmer, M.; Hanslmeier, A.

154

Coronal Mass Ejection of 26 February 2000: Complete analysis of the three-part CME structure  

NASA Astrophysics Data System (ADS)

We analyze the kinematics and morphology of the limb coronal mass ejection (CME) of 26 February 2000, utilizing observations from Mauna Loa Solar Observatory (MLSO), the Solar and Heliospheric Observatory (SOHO) and the Geostationary Operational Environmental Satellite (GOES). Also, we analyze the relation between dynamics of the CME and the energy release in the associated flare. An intricate structure (prominence, prominence-like absorbing feature, cavity and bright overlying arcade) is clearly recognizable in the low corona during the pre-eruption phase of slow rise. This provided measurements of kinematics of verious features from the very beginning of the eruption up to the post-acceleration phase which was followed up to 32 solar radii. Such events are observed only occasionaly, and are of great importance for the comprehension of the nature of forces driving CMEs. The acceleration maximum was attained at the radial distance of 2.4 solar radii from the solar center and ceased beyond 12 solar radii. The time profiles of the acceleration of various features of CME are showing "self-similar" expansion and implying a common driver. The acceleration phase was synchronized to a certain degree with the impulsive phase of the associated two-ribbon flare. Observations provide clear evidence that CME eruption caused a global restructuring of the magnetic field in the outer and inner corona. Furthermore, kinematics and morphological properties of this CME show possibility that in some events the prominence can evolve into a structure which looks like three-part structure CME, i.e. where the frontal rim is just a part of helically twisted prominence.

Mari?i?, D.; Vršnak, B.; Roša, D.; Hržina, D.

2012-11-01

155

Enhancing Quality Improvements in Cancer Care Through CME Activities at a Nationally Recognized Cancer Center  

PubMed Central

Changing healthcare policy will undoubtedly affect the healthcare environment in which providers function. The current Fee for Service reimbursement model will be replaced by Value-Based Purchasing, where higher quality and more efficient care will be emphasized. Because of this, large healthcare organizations and individual providers must adapt to incorporate performance outcomes into patient care. Here, we present a Continuing Medical Education (CME)-based initiative at the City of Hope National Cancer Center that we believe can serve as a model for using CME as a value added component to achieving such a goal.

Uemura, Marc; Morgan, Robert; Mendelsohn, Mary; Kagan, Jean; Saavedra, Crystal; Leong, Lucille

2013-01-01

156

Role of Ambient Solar Wind Conditions in CME evolution (P21)  

NASA Astrophysics Data System (ADS)

ipsraj@yahoo.com Solar events are mainly responsible for producing storms at the Earth. Coronal Mass Ejection (CME) is a major cause for this. In this paper, Coronal Mass Ejections occurred during 1998-2004 are studied. Ambient solar wind does play some role in determining the effect of a CME. The effects produced at the Earth during the period 1999 2004 are considered and an attempt has been made to understand the role of ambient solar wind. This is to draw some conclusion about how some of the events become geo- effective.

Jadav, R.; Jadeja, A. K.; Iyer, K. N.

2006-11-01

157

The interplay of phase inversion, polymer membrane formation, and drug release in a membrane-based delivery system  

Microsoft Academic Search

The interplay between the dynamics of phase inversion, membrane formation, and drug release kinetics has been studied for solvent-cast films of a poly(n-butyl cyanoacrylate) (PBCA)–naproxen system. Films cast from solutions containing various amounts of polymer, solvent (acetone) and non-solvent (water) were analyzed via electron microscopy to determine optimal compositions and casting conditions leading to the formation of desired porous morphologies.

Aishuang Xiang; Decheng Ma; Anthony J. McHugh

2010-01-01

158

Interrater Reliability to Assure Valid Content in Peer Review of CME-Accredited Presentations  

ERIC Educational Resources Information Center

Introduction: The Accreditation Council for Continuing Medical Education (ACCME) provides guidelines for continuing medical education (CME) materials to mitigate problems in the independence or validity of content in certified activities; however, the process of peer review of materials appears largely unstudied and the reproducibility of…

Quigg, Mark; Lado, Fred A.

2009-01-01

159

Constraints on CME Evolution from in situ Observations of Ionic Charge States  

NASA Technical Reports Server (NTRS)

We present a novel procedure for deriving the physical properties of Coronal Mass Ejections (CMES) in the corona. Our methodology uses in-situ measurements of ionic charge states of C, O, Si and Fe in the heliosphere and interprets them in the context of a model for the early evolution of ICME plasma, between 2 - 5 R-solar. We find that the data can be fit only by an evolution that consists of an initial heating of the plasma, followed by an expansion that ultimately results in cooling. The heating profile is consistent with a compression of coronal plasma due to flare reconnect ion jets and an expansion cooling due to the ejection, as expected from the standard CME/flare model. The observed frozen-in ionic charge states reflect this time-history and, therefore, provide important constraints for the heating and expansion time-scales, as well as the maximum temperature the CME plasma is heated to during its eruption. Furthermore, our analysis places severe limits on the possible density of CME plasma in the corona. We discuss the implications of our results for CME models and for future analysis of ICME plasma composition.

Gruesbeck, Jacob R.; Lepri, Susan T.; Zurbuchen, Thomas H.; Antiochos, Spiro K.

2010-01-01

160

Webinar Speakers December 2, 2011 - Frontiers in Nutrition and Cancer Prevention: Online CME Series  

Cancer.gov

Frontiers in Nutrition and Cancer Prevention: Online CME Series Vitamin D and Cancer Prevention: Shining Light on the Current Research Friday, December 02, 2011 12:00 – 1:30 pm EST SPEAKERS Dietary Guidelines: How Much Is Enough? How Much Is Too Much? JoAnn

161

CME Parameter Input to ENLIL: LASCO halo cone versus STEREO measurements  

NASA Astrophysics Data System (ADS)

ENLIL is a well-known model in the solar-helio community (Odstrcil and Pizzo, 1999) and is frequently used to predict the arrival of coronal mass ejections (CMEs) at Earth based on observations from the SOHO LASCO coronagraphs. The halo CME parameters needed to drive ENLIL are the CME size, speed, and direction, and these are typically derived from fitting a "cone model" to the LASCO CME images to drive interplanetary disturbances through the inner heliosphere (Xie et al., 2004). But as seen from a single vantage point along the Sun-Earth line, it is difficult to determine these projected CME parameters unambiguously (e.g., Gopalswamy et al., 2009). Over the past few years we have been in the fortunate circumstance of having the twin STEREO spacecraft (Kaiser et al., 2008) at quadrature with the Sun-Earth line, so we can compare directly the validity of the cone model with actual measurements of the CMEs heading toward Earth. We report here on a comparison of more than twenty SOHO LASCO halo coronal mass ejections that were also observed by STEREO between 2008 and mid-2011.

St Cyr, O. C.; Orlove, M.; Xie, H.; Gilbert, H. R.; Odstrcil, D.; Gopalswamy, N.; Mays, M. L.; Quirk, C. A.; Henning, C.

2011-12-01

162

The Role of Coronal Holes in CME Deflection in the Lower Corona  

NASA Astrophysics Data System (ADS)

Coronal mass ejections (CMEs) are known to be deflected when ejected near a coronal hole (Gopalswamy et al. 2009). We present results from simulations of CMEs near a coronal hole (CH) using a 3D magnetohydrodymics model - the Space Weather Modeling Framework. We propose magnetic tension and pressure as a cause of the CME deflection from the disturbed magnetic field lines of the simulation coronal hole. The solar wind is driven via Alfven waves and Kolmogorov-like dissipation and surface Alfven wave damping are considered for the dissipation of the waves (Evans et al. 2011). The magnetic field at the inner boundary is specified with synoptic magnetogram data from Carrington Rotation 2029, which corresponds to April 21 to May 18, 2005. CMEs are generated by inserting an out of equilibrium modified Titov-Demoulin flux rope into active region (AR) 0758. Treating the CME as a solid body we calculate the expected deflection from the coronal hole field lines. We compare this value to the actual path of the simulated CMEs for which we define a deflection angle as the difference between the observed path and the radial vector connecting the center of the Sun and the CME launch site. Finally, we generalize the deflection by seeing how it scales with several physical parameters such as CME mass, velocity and the separation of the AR and CH as well as its intensity. We compare our simulated and estimated values with observed deflections (Gopalswamy et. al 2009)

Kay, C.; Opher, M.; Evans, R. M.; Gombosi, T. I.

2011-12-01

163

Forecast evaluation of the coronal mass ejection (CME) geoeffectiveness using halo CMEs from 1997 to 2003  

Microsoft Academic Search

In this study we have made a forecast evaluation of geoeffective coronal mass ejections (CMEs) by using frontside halo CMEs and the magnetospheric ring current index, Dst. This is the first time, to our knowledge, that an attempt has been made to construct contingency tables depending on the geoeffectiveness criteria as well as to estimate the probability of CME geoeffectiveness

R.-S. Kim; K.-S. Cho; Y.-J. Moon; Y.-H. Kim; Y. Yi; M. Dryer; Su-Chan Bong; Y.-D. Park

2005-01-01

164

Geoeffective CME-driven Shocks: Comparison Between Imaging Data and in-situ Observations  

Microsoft Academic Search

Fast Coronal Mass Ejections (CMEs) drive shock waves that can be recognized in the coronagraph images. Properties of the shock and the CME, such as density compression ratio, mass, kinetic energy, and the direction of propagation, can be measured from these images. The aim of this study is: (1) to compare these properties with in-situ measurements of the large scale

V. Ontiveros; A. Gonzalez-Esparza; A. Vourlidas

2009-01-01

165

Are CME 'interactions' Really Important for Accelerating Major Solar Energetic Particle Events?  

NASA Technical Reports Server (NTRS)

Recent studies have proposed that the presence or absence of an interaction with a preceding coronal mass ejection (CME) or other coronal structure within approximately 50R(sub s), of the Sun discriminates large, fast CMEs associated with major solar energetic particle (SEP) events from those that are not. We conclude that there is no compelling evidence that, if such interactions take place, they play an important role in SEP acceleration. Reasons include: The reported statistical results are consistent with a chance association between interacting CMEs and SEP events; Energetic SEPs are detected at Earth typically before or around the time when the primary CME enters the LASCO C2 field of view - interactions higher in the corona cannot play a role in acceleration of these particles; For approximately 60% of major SEP events in 1997-2001, the preceding CME fades into the background corona or is relatively narrow (less than 40 deg), suggesting any interaction will be weak; Radio signatures attributed to CME interaction occur after SEP acceleration has commenced.

Richardson, I. G.; Lawrence, G. R.; Haggerty, D. K.; Kucera, T.; Szabo, A.

2002-01-01

166

The Global Magnetic Topology of the Solar Corona Preceding CME Eruptions  

Microsoft Academic Search

Understanding coronal mass ejections (CMEs) is a key step to understanding and eventually predicting Space Weather. Three CME event periods have gained great interest lately due to the wide range of observations made before, during and after each event. These include the Halloween storms from October 2003, the eruption involving AR 8210 during CR 1935, and the May 12, 1997

S. A. Ledvina; J. G. Luhmann; Y. Li; B. Abbett; C. Arge

2005-01-01

167

Superposed epoch analyses of ion temperatures during CME- and CIR/HSS-driven storms  

NASA Astrophysics Data System (ADS)

Coronal mass ejections (CMEs) and corotating interaction regions associated with high speed solar wind streams (CIR/HSSs) drive geomagnetic storms in the terrestrial magnetosphere. Each type of storm driver yields different dynamics of storm evolution. We present results from comparative superposed epoch analyses of global ion temperatures calculated from TWINS energetic neutral atom (ENA) data and simulations using the comprehensive ring current model (CRCM). During the June 2008-April 2012 timeframe, 48 geomagnetic storms (minimum Dst?-40 nT) occurred. Of these, 21 storms were CME-driven and 15 were driven by CIR/HSSs. Superposed epoch analysis results demonstrate that ion temperatures increase during the recovery phase of CIR/HSS-driven storms, while ions are rapidly heated at the commencement of CME-driven storms then cool over the main phase, particularly for intense (minimum Dst?-78 nT) CME-driven storms. Higher energy ions are convected to lower L-shells during CME-driven storms, while CIR/HSS-driven storms tend to have average ion temperatures that are higher on the dayside than nightside.

Keesee, A. M.; Elfritz, J. G.; Fok, M.-C.; McComas, D. J.; Scime, E. E.

2014-08-01

168

Correlated Flare and CME Energies for the October/November 2003 Events  

NASA Technical Reports Server (NTRS)

We find a strong correlation between the kinetic energies (KEs) of the coronal mass ejections (CMEs) and the radiated energies of the associated solar flares for the events that occurred during the period of intense solar activity between 18 October and 08 November 2003. CME start times, speeds, mass, and KEs were taken from Gopalswamy et al. (2005), who used SOHO/LASCO observations. The GOES observations of the associated flares were analyzed to find the peak SXR flux, the radiated energy in SXRs (L(sub sxr)), and the radiated energy from the SXR emitting plasma across all wavelengths (L(sub hot)). RHESSI observations were also used to find the energy in non-thermal electrons, ions, and the plasma thermal energy for some events. For two events, SORCE/TIM observations of the total solar irradiance during a flare were also available to give the total radiated flare energy (L(sub total)). We find that the total flare energies of the larger events are of the same order of magnitude as the CME KE with a stronger correlation than has been found in the past for other time intervals. The following rule-of-thumb (good to an order of magnitude for the larger events} can be used to relate flare and CME energies: CME KE l(sub total) 10 L(sub hot) 100 L(sub SXR).

Dennis, Brian R.; Haga, Leah; Medlin, Drew; Tolbert, A. Kimberly

2006-01-01

169

Organizational Change in Management of Hepatitis C: Evaluation of a CME Program  

ERIC Educational Resources Information Center

Introduction: Effective treatment regimens exist for the hepatitis C virus (HCV); however, clinicians are often resistant to evaluation or treatment of patients with alcohol or substance abuse problems. We describe a continuing medical education (CME) program for clinicians in a nationwide health care system, with emphasis on current treatment…

Garrard, Judith; Choudary, Veena; Groom, Holly; Dieperink, Eric; Willenbring, Mark L.; Durfee, Janet M.; Ho, Samuel B.

2006-01-01

170

When to Recommend Compulsory versus Optional CME Programs? A Study to Establish Criteria.  

ERIC Educational Resources Information Center

A study designed to establish criteria for requiring continuing medical education (CME) for family physicians by analyzing 14 structured oral interviews (SOIs) with physicians. The SOI consists of 40 cases, focuses on 10 aspects of physician competence required to face critical practice issues. Judges determined from the interviews a number of…

Miller, Francois; Jacques, Andre; Brailovsky, Carlos; Sindon, Andre; Bordage, Georges

1997-01-01

171

Knowledge Gained After a Brief CME Module on Breast Cancer Diagnosis  

Microsoft Academic Search

Background. In developing countries, continuing medical education (CME) is lacking and physicians' knowledge of cancer control may also be lacking. Method. We evaluated knowl­ edge of 144 primary care physicians in Egypt and 50 in Tunisia regarding breast cancer (BC) and inflammatory BC (IBC) in particular. We invited the physicians to pretesting, presentation of an educational module, and posttesting. Results.

NAMRATA M. SHAH; AMR S. SOLIMAN; MOUSUMI BANERJEE; SOFIA D. MERAJVER; KADRY ISMAIL; IBRAHIM SEIFELDIN; AHMED HABLAS; ALI ZARZOUR; ATEF ABDEL-AZIZ; FARHAT BEN AYED; ROBERT M. CHAMBERLAIN

172

Reconciling CME Kinematics using Radio and White-light Observations from STEREO and SOHO  

NASA Astrophysics Data System (ADS)

We study the characteristics of nonthermal radio emission associated with coronal mass ejections (CMEs) observed by STEREO, SOHO, and Wind spacecraft. In particular, we examine three backside CMEs associated with type II radio bursts at frequencies below 16 MHz. These bursts are known to be excellent indicators of solar energetic particle events. We use the universal drift rate spectrum of type II radio bursts and the inferred density scale heights in the corona and interplanetary medium o estimate the speed of the shock waves that produce the type II radio bursts. We find that the radio bursts can provide an accurate estimate of the CME speeds. We consider three backside events and a cannibalism event to show the usefulness of radio dynamic spectrum in inferring CME kinematics. We use radio direction finding technique to show that CME-CME interaction results in enhanced nonthermal radio emission. The radio data also provide constraints on the particle acceleration mechanisms and the reason for the energetic particles observed at wide-ranging longitudes. Finally we infer the shape and extent of the shock associated with one of the biggest solar energetic particle events in the space era.

Gopalswamy, Nat; Yashiro, Seiji; Xie, Hong; Makela, Pertti; Akiyama, Sachiko; Reiner, Michael; MacDowall, Robert

2014-05-01

173

Local delivery of rolipram, a phosphodiesterase-4-specific inhibitor, augments bone morphogenetic protein-induced bone formation  

Microsoft Academic Search

Recombinant human bone morphogenetic protein (rhBMP) is a promising therapeutic cytokine for the induction of bone formation,\\u000a but a weak response in humans remains a major hurdle in its therapeutic application. We have previously reported an rhBMP-2-induced\\u000a increase in the bone mass of mice receiving systemic rolipram, a specific inhibitor of phosphodiesterase-4. To overcome the\\u000a side effects of systemic administration

Yoshio Tokuhara; Shigeyuki Wakitani; Yuuki Imai; Chizumi Nomura; Masatoshi Hoshino; Koichi Yano; Susumu Taguchi; Mitsunari Kim; Yoshinori Kadoya; Kunio Takaoka

2010-01-01

174

Competitive displacement of drugs from cyclodextrin inclusion complex by polypseudorotaxane formation with poloxamer: implications in drug solubilization and delivery.  

PubMed

The competitive interactions between the poly-[propylene oxide] (POO)-poly-[ethylene oxide] (PEO) block copolymer poloxamer 407 (Pluronic F127) and two drugs, triamcinolone acetonide and ciclopirox olamine, by the formation of inclusion complexes with two cyclodextrin hydrophilic derivatives, hydroxypropyl-?-cyclodextrin (HP?CD; molar substitution (MS) 0.65) and partially methylated-?-cyclodextrin (M?CD; MS 0.57), were studied by means of one-dimensional (1)H NMR, 2D ROESY experiments, solubility studies and drug release studies. 1D and 2D NMR and solubility studies indicate that both triamcinolone acetonide and ciclopirox olamine form stable inclusion complexes with the cyclodextrin derivatives. In the case of ciclopirox olamine the complex was more stable at pH 1. Effective complexation of poloxamer with the two cyclodextrins (CDs) was also evidenced by NMR analysis, and competitive displacement of the drugs from the CD cavity by the polymer was observed. Drug solubility in CD solutions was not modified by the addition of polymers, indicating that a decrease in solubility due to the competitive displacement is probably compensated by the solubilizing effect of polymer micellization. Finally, polypseudorotaxanes formation has a significant influence on the release of the drugs studied. Changes in the release rate depend on the stability of drug-CD inclusion complex and on cyclodextrin concentration in the bulk solution; so polypseudorotaxane formation can be employed to modulate drug controlled release from thermosensitive hydrogels. PMID:22182528

Nogueiras-Nieto, Luis; Sobarzo-Sánchez, Eduardo; Gómez-Amoza, José Luis; Otero-Espinar, Francisco J

2012-04-01

175

Induction of reparative dentin formation by ultrasound-mediated gene delivery of growth/differentiation factor 11.  

PubMed

Bone morphogenetic proteins (BMPs) are morphogens implicated in embryonic and regenerative odontogenic differentiation. Gene therapy has the potential to induce reparative dentin formation for potential pulp capping. We have optimized the gene transfer of Growth/differentiation factor 11 (Gdf11)/Bmp11 plasmid DNA into dental pulp stem cells by sonoporation in vivo. Dental pulp tissue treated with plasmid pEGFP or CMV-LacZ in 5-10% Optison (Molecular Biosystems Inc., San Diego, CA) and stimulated by ultrasound (1 MHz, 0.5 W/cm(2), 30 sec) showed significant efficiency of gene transfer and high level of protein production selectively in the local region, within 500 microm of the amputated site of the pulp tissue. The Gdf11 cDNA plasmid transferred into dental pulp tissue by sonoporation in vitro, induced the expression of dentin sialoprotein (Dsp), a differentiation marker for odontoblasts. The transfection of Gdf11 by sonoporation stimulated a large amount of reparative dentin formation on the amputated dental pulp in canine teeth in vivo. These results suggest the possible use of BMPs using ultrasound-mediated gene therapy for endodontic dental treatment. PMID:12718768

Nakashima, Misako; Tachibana, Katsuro; Iohara, Koichiro; Ito, Masataka; Ishikawa, Masaki; Akamine, Akifumi

2003-04-10

176

The SCEC Community Modeling Environment(SCEC/CME): A Collaboratory for Seismic Hazard Analysis  

NASA Astrophysics Data System (ADS)

The SCEC Community Modeling Environment (SCEC/CME) Project is an NSF-supported Geosciences/IT partnership that is actively developing an advanced information infrastructure for system-level earthquake science in Southern California. This partnership includes SCEC, USC's Information Sciences Institute (ISI), the San Diego Supercomputer Center (SDSC), the Incorporated Institutions for Research in Seismology (IRIS), and the U.S. Geological Survey. The goal of the SCEC/CME is to develop seismological applications and information technology (IT) infrastructure to support the development of Seismic Hazard Analysis (SHA) programs and other geophysical simulations. The SHA application programs developed on the Project include a Probabilistic Seismic Hazard Analysis system called OpenSHA. OpenSHA computational elements that are currently available include a collection of attenuation relationships, and several Earthquake Rupture Forecasts (ERFs). Geophysicists in the collaboration have also developed Anelastic Wave Models (AWMs) using both finite-difference and finite-element approaches. Earthquake simulations using these codes have been run for a variety of earthquake sources. Rupture Dynamic Model (RDM) codes have also been developed that simulate friction-based fault slip. The SCEC/CME collaboration has also developed IT software and hardware infrastructure to support the development, execution, and analysis of these SHA programs. To support computationally expensive simulations, we have constructed a grid-based scientific workflow system. Using the SCEC grid, project collaborators can submit computations from the SCEC/CME servers to High Performance Computers at USC and TeraGrid High Performance Computing Centers. Data generated and archived by the SCEC/CME is stored in a digital library system, the Storage Resource Broker (SRB). This system provides a robust and secure system for maintaining the association between the data seta and their metadata. To provide an easy-to-use system for constructing SHA computations, a browser-based workflow assembly web portal has been developed. Users can compose complex SHA calculations, specifying SCEC/CME data sets as inputs to calculations, and calling SCEC/CME computational programs to process the data and the output. Knowledge-based software tools have been implemented that utilize ontological descriptions of SHA software and data can validate workflows created with this pathway assembly tool. Data visualization software developed by the collaboration supports analysis and validation of data sets. Several programs have been developed to visualize SCEC/CME data including GMT-based map making software for PSHA codes, 4D wavefield propagation visualization software based on OpenGL, and 3D Geowall-based visualization of earthquakes, faults, and seismic wave propagation. The SCEC/CME Project also helps to sponsor the SCEC UseIT Intern program. The UseIT Intern Program provides research opportunities in both Geosciences and Information Technology to undergraduate students in a variety of fields. The UseIT group has developed a 3D data visualization tool, called SCEC-VDO, as a part of this undergraduate research program.

Maechling, P. J.; Jordan, T. H.; Minster, J. B.; Moore, R.; Kesselman, C.

2005-12-01

177

INVESTIGATION OF THE FORMATION AND SEPARATION OF AN EXTREME-ULTRAVIOLET WAVE FROM THE EXPANSION OF A CORONAL MASS EJECTION  

SciTech Connect

We address the nature of EUV waves through direct observations of the formation of a diffuse wave driven by the expansion of a coronal mass ejection (CME) and its subsequent separation from the CME front. The wave and the CME on 2011 June 7 were well observed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. Following the solar eruption onset, marked by the beginning of the rapid increasing of the CME velocity and the X-ray flux of accompanying flare, the CME exhibits a strong lateral expansion. During this impulsive expansion phase, the expansion speed of the CME bubble increases from 100 km s{sup -1} to 450 km s{sup -1} in only six minutes. An important finding is that a diffuse wave front starts to separate from the front of the expanding bubble shortly after the lateral expansion slows down. Also a type II burst is formed near the time of the separation. After the separation, two distinct fronts propagate with different kinematic properties. The diffuse front travels across the entire solar disk, while the sharp front rises up, forming the CME ejecta with the diffuse front ahead of it. These observations suggest that the previously termed EUV wave is a composite phenomenon and driven by the CME expansion. While the CME expansion is accelerating, the wave front is cospatial with the CME front, thus the two fronts are indiscernible. Following the end of the acceleration phase, the wave moves away from the CME front with a gradually increasing distance between them.

Cheng, X.; Ding, M. D. [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Zhang, J. [School of Physics, Astronomy and Computational Sciences, George Mason University, Fairfax, VA 22030 (United States); Olmedo, O. [NRC, Naval Research Laboratory, Washington, DC 20375 (United States); Vourlidas, A. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Liu, Y., E-mail: dmd@nju.edu.cn, E-mail: jzhang7@gmu.edu [Space Science Laboratory, University of California, Berkeley, CA 94720 (United States)

2012-01-20

178

Diversity of planetary systems in low-mass disks. Terrestrial-type planet formation and water delivery  

NASA Astrophysics Data System (ADS)

Context. Several studies, observational and theoretical, suggest that planetary systems with only rocky planets are the most common in the Universe. Aims: We study the diversity of planetary systems that might form around Sun-like stars in low-mass disks without gas-giant planets. We focus especially on the formation process of terrestrial planets in the habitable zone (HZ) and analyze their water contents with the goal to determine systems of astrobiological interest. In addition, we study the formation of planets on wide orbits because they can be detected with the microlensing technique. Methods: N-body simulations of high resolution were developed for a wide range of surface density profiles. A bimodal distribution of planetesimals and planetary embryos with different physical and orbital configurations was used to simulate the planetary accretion process. The surface density profile combines a power law for the inside of the disk of the form r-?, with an exponential decay to the outside. We performed simulations adopting a disk of 0.03 M? and values of ? = 0.5, 1 and 1.5. Results: All our simulations form planets in the HZ with different masses and final water contents depending on the three different profiles. For ? = 0.5, our simulations produce three planets in the HZ with masses ranging from 0.03 M? to 0.1 M? and water contents between 0.2 and 16 Earth oceans (1 Earth ocean =2.8 × 10-4 M?). For ? = 1, three planets form in the HZ with masses between 0.18 M? and 0.52 M? and water contents from 34 to 167 Earth oceans. Finally, for ? = 1.5, we find four planets in the HZ with masses ranging from 0.66 M? to 2.21 M? and water contents between 192 and 2326 Earth oceans. This profile shows distinctive results because it is the only one of those studied here that leads to the formation of water worlds. Conclusions: Since planetary systems with ? = 1 and 1.5 present planets in the HZ with suitable masses to retain a long-lived atmosphere and to maintain plate tectonics, they seem to be the most promising candidates to be potentially habitable. Particularly, these systems form Earths and Super-Earths of at least 3 M? around the snow line, which can be discovered by the microlensing technique.

Ronco, M. P.; de Elía, G. C.

2014-07-01

179

Effect of Autologous Bone Marrow Stromal Cell Seeding and Bone Morphogenetic Protein-2 Delivery on Ectopic Bone Formation in a Microsphere/Poly(Propylene Fumarate) Composite  

PubMed Central

A biodegradable microsphere/scaffold composite based on the synthetic polymer poly(propylene fumarate) (PPF) holds promise as a scaffold for cell growth and sustained delivery vehicle for growth factors for bone regeneration. The objective of the current work was to investigate the in vitro release and in vivo bone forming capacity of this microsphere/scaffold composite containing bone morphogenetic protein-2 (BMP-2) in combination with autologous bone marrow stromal cells (BMSCs) in a goat ectopic implantation model. Three composites consisting of 0, 0.08, or 8??g BMP-2?per mg of poly(lactic-co-glycolic acid) microspheres, embedded in a porous PPF scaffold, were combined with either plasma (no cells) or culture-expanded BMSCs. PPF scaffolds impregnated with a BMP-2 solution and combined with BMSCs as well as empty PPF scaffolds were also tested. The eight different composites were implanted subcutaneously in the dorsal thoracolumbar area of goats. Incorporation of BMP-2–loaded microspheres in the PPF scaffold resulted in a more sustained in vitro release with a lower burst phase, as compared to BMP-2–impregnated scaffolds. Histological analysis after 9 weeks of implantation showed bone formation in the pores of 11/16 composites containing 8??g/mg BMP-2–loaded microspheres with no significant difference between composites with or without BMSCs (6/8 and 5/8, respectively). Bone formation was also observed in 1/8 of the BMP-2–impregnated scaffolds. No bone formation was observed in the other conditions. Overall, this study shows the feasibility of bone induction by BMP-2 release from microspheres/scaffold composites.

Kempen, Diederik H.R.; Kruyt, Moyo C.; Lu, Lichun; Wilson, Clayton E.; Florschutz, Anthony V.; Yaszemski, Michael J.; Dhert, Wouter J.A.

2009-01-01

180

Three-dimensional global simulation of CME/ICME/Shock propagation from Sun to the heliosphere  

NASA Astrophysics Data System (ADS)

This study performs simulations of the propagation of coronal mass ejections from the Sun to the Earth through a realistic 3D solar wind structure. The famous solar event of 12 May 1997, described observationally by Thompson et al. [1998, 1999] and theoretically by Wu et al. [2001], is used as motivation for this simulation. The newly developed code, HAF+3DMHD combines two simulation codes, Hakamada-Akasofu-Fry code (HAF) version 2 (HAFv.2) [Fry et al., 2001] and a fully three-dimensional, time-dependent MHD simulation code [Han et al, 1988]. The solar wind structure is simulated, using the HAF code, out to 0.08 AU from source surface maps derived from solar magnetograms. The HAF simulation is then used as input for the lower boundary of a 3D MHD code to calculate the evolution of solar wind plasma beyond 18 solar radii (0.08 AU). A dynamic disturbance is delivered to this non-uniform structure to model the evolution and interplanetary propagation of a coronal mass ejection (ICME, including its shock). We also integrate the changing line-of-sight heliospheric density to compare to data observed by the LASCO instrument on SOHO, and we compare the derived ICME and shock structure at 1 AU to WIND solar wind data for this 12 May 1997 event. This new code provides a tool to link the general cases of ICME at 1 AU to their solar sources, as well as to identify the possible origins of shock formation due to CMEs and CME/CIR interactions. In the case of complex or interacting ejecta, model interpretation is often required to accurately determine the solar sources of the ejecta observed at 1 AU. Because this newly developed model incorporates 3D MHD, its results can be extended to simulate coronal and heliospheric observations, including the ambient medium's non-uniformity provided by the HAFv.2 model, from the upcoming STEREO mission. Reference: Fry et al., JGR, 106, 20985-21001, 2001. Han et al., Comp. and Fluids, 16, 81-103, 1988. Thompson et al., GRL, 25, 2465-2468, 1998. Thompson et al., AP. J. Lett., 517, L151-L155, 1999. Wu et al., JGR, 106, 25089-25102, 2001.

Wu, C.; Fry, C.; Thompson, B. J.; Wu, S.; Dryer, M.; Liou, K.

2005-12-01

181

43 CFR 11.42 - How does the authorized official apply the NRDAM/CME or NRDAM/GLE?  

Code of Federal Regulations, 2013 CFR

...the Interior NATURAL RESOURCE DAMAGE ASSESSMENTS Type A Procedures § 11.42...CME or NRDAM/GLE indicates damages in excess of $100,000, then...000; or (2) Compute all damages using type B procedures....

2013-10-01

182

Combining Models, Theory and Observations to Reconstruct CME and Shock Morphology and Create an Empirical Prediction Model  

NASA Astrophysics Data System (ADS)

There are many factors that contribute to the evolution and propagation of a Coronal Mass Ejection as well as associated shock waves in the interplanetary space, including both the initial characteristics of the CME as well as the physical quantities of the solar wind regime the CME will be encountering. No one data set contains enough information to constrain these parameters, but by combining a number of different data sets including in-situ solar wind measurements, remote sensing white light and EUV observations, numerical models and using a theoretical propagation model based on aerodynamic drag, the study of multiple events can lead to an empirical prediction model for the arrival of both the CME ejecta and shock at the Earth. The more events that are studied the more accurate the results will be as the forces governing CME acceleration/deceleration are better understood.

Hess, Phillip; Zhang, Jie

2014-06-01

183

Effects of Hysteresis Between Maximum CME Speed Index and Typical Solar Activity Indicators During Cycle 23  

NASA Astrophysics Data System (ADS)

Using the smoothed time series of maximum CME speed index for solar cycle 23, it is found that this index, analyzed jointly with six other solar activity indicators, shows a hysteresis phenomenon. The total solar irradiance, coronal index, solar radio flux (10.7 cm), Mg ii core-to-wing ratio, sunspot area, and H? flare index follow different paths for the ascending and the descending phases of solar cycle 23, while a saturation effect exists at the maximum phase of the cycle. However, the separations between the paths are not the same for the different solar activity indicators used: the H? flare index and total solar irradiance depict broad loops, while the Mg ii core-to-wing ratio and sunspot area depict narrow hysteresis loops. The lag times of these indices with respect to the maximum CME speed index are discussed, confirming that the hysteresis represents a clue in the search for physical processes responsible for changing solar emission.

Özgüç, A.; Kilcik, A.; Rozelot, J. P.

2012-12-01

184

Testing model for prediction system of 1-AU arrival times of CME-associated interplanetary shocks  

NASA Astrophysics Data System (ADS)

We test a model to predict arrival times of interplanetary shock waves associated with coronal mass ejections (CMEs) using a three-dimensional adaptive mesh refinement (AMR) code. The model is used for the prediction system we develop, which has a Web-based user interface and aims at people who is not familiar with operation of computers and numerical simulations or is not researcher. We apply the model to interplanetary CME events. We first choose coronal parameters so that property of background solar wind observed by ACE space craft is reproduced. Then we input CME parameters observed by SOHO/LASCO. Finally we compare the predicted arrival times with observed ones. We describe results of the test and discuss tendency of the model.

Ogawa, Tomoya; den, Mitsue; Tanaka, Takashi; Sugihara, Kohta; Takei, Toshifumi; Amo, Hiroyoshi; Watari, Shinichi

185

Critical Role of Multidrug Efflux Pump CmeABC in Bile Resistance and In Vivo Colonization of Campylobacter jejuni  

PubMed Central

CmeABC functions as a multidrug efflux pump contributing to the resistance of Campylobacter to a broad range of antimicrobials. In this study, we examined the role of CmeABC in bile resistance and its contribution to the adaptation of Campylobacter jejuni in the intestinal tract of the chicken, a natural host and a major reservoir for Campylobacter. Inactivation of cmeABC drastically decreased the resistance of Campylobacter to various bile salts. Addition of choleate (2 mM) in culture medium impaired the in vitro growth of the cmeABC mutants but had no effect on the growth of the wild-type strain. Bile concentration varied in the duodenum, jejunum, and cecum of chicken intestine, and the inhibitory effect of the intestinal extracts on the in vitro growth of Campylobacter was well correlated with the total bile concentration in the individual sections of chicken intestine. When inoculated into chickens, the wild-type strain colonized the birds as early as day 2 postinoculation with a density as high as 107 CFU/g of feces. In contrast, the cmeABC mutants failed to colonize any of the inoculated chickens throughout the study. The minimum infective dose for the cmeABC mutant was at least 2.6 × 104-fold higher than that of the wild-type strain. Complementation of the cmeABC mutants with a wild-type cmeABC allele in trans fully restored the in vitro growth in bile-containing media and the in vivo colonization to the levels of the wild-type strain. Immunoblotting analysis indicated that CmeABC is expressed and immunogenic in chickens experimentally infected with C. jejuni. Together, these findings provide compelling evidence that CmeABC, by mediating resistance to bile salts in the intestinal tract, is required for successful colonization of C. jejuni in chickens. Inhibition of CmeABC function may not only control antibiotic resistance but also prevent the in vivo colonization of pathogenic Campylobacter.

Lin, Jun; Sahin, Orhan; Overbye Michel, Linda; Zhang, Qijing

2003-01-01

186

Geoeffectiveness of CIR and CME Events: Factors Contributing to Their Differences  

Microsoft Academic Search

Recent work has shown that solar wind-magnetosphere coupling is moreefficient for CIR-driven events than for CME-driven events. The studyherein looks into the individual physical parameters of Corotating Interaction Regions (CIRs) and Coronal Mass Ejections (CMEs) and looks to isolate particular characteristics that leads to greater coupling ofenergy from the solar wind into the magnetosphere for certain classesof magnetic storms. While

Laura K. Laughlin; Niescja E. Turner; Elizabeth J. Mitchell

2008-01-01

187

GEOEFFECTIVENESS OF CIR AND CME EVENTS: FACTORS CONTRIBUTING TO THEIR DIFFERENCES  

Microsoft Academic Search

Recent work has shown that solar wind-magnetosphere coupling is more efficient for CIR-driven events than for CME-driven events. The study herein looks into the individual physical parameters of Corotating Interaction Regions (CIRs) and Coronal Mass Ejections (CMEs) and looks to isolate particular characteristics that leads to greater coupling of energy from the solar wind into the magnetosphere for certain classes

LAURA K. LAUGHLIN; NIESCJA E. TURNER

188

Suppression of Active-Region CME Production by the Presence of Other Active Regions  

NASA Technical Reports Server (NTRS)

From the SOHO mission s data base of MDI full-disk magnetograms spanning solar cycle 23, we have obtained a set of 40,000 magnetograms of 1,300 active regions, tracking each active region across the 30 degree central solar disk. Each active region magnetogram is cropped from the full-disk magnetogram by an automated code. The cadence is 96 minutes. From each active-region magnetogram, we have measured two whole-active-region magnetic quantities: (1) the magnetic size of the active region (the active region s total magnetic flux), and (2) a gauge of the active region s free magnetic energy (part of the free energy is released in the production of a flare and/or CME eruption). From NOAA Flare/CME catalogs, we have obtained the event (Flare/CME/SEP event) production history of each active region. Using all these data, we find that for each type of eruptive event, an active region s expected rate of event production increases as a power law of our gauge of active-region free magnetic energy. We have also found that, among active regions having nearly the same free energy, the rate of the CME production is less when there are many other active regions on the disk than when there are few or none, but there is no significant discernible suppression of the rate of flare production. This indicates that the presence of other active regions somehow tends to inhibit an active region s flare-producing magnetic explosions from becoming CMEs, contrary to the expectation from the breakout model for the production of CMEs.

Falconer, David; Moore, Ron; Barghouty, Abdulnasser; Khazanov, Igor

2009-01-01

189

The double-belt outer radiation belt during CME- and CIR-driven geomagnetic storms  

NASA Astrophysics Data System (ADS)

We have identified eight events with double-belt structure in the outer radiation belt from 110 coronal mass ejection (CME) driven magnetic storms and 223 corotating interaction regions (CIR) driven storms during 1994 to 2003 based on the SAMPEX data sets. Among them, three cases are related to CME-driven magnetic storms and five cases are related CIR-driven storms. All double-belt structure events in the outer radiation belt are found during the recovery phase of a magnetic storm for both CME- and CIR-related events—they usually start to form within 3-4 days after the onset of the magnetic storm. The preconditions needed to form a double-belt structure, for all the CME-related events, are found to be high solar wind dynamic pressure (Pdy) and southward interplanetary magnetic field Bz; nevertheless, for the CIR-related events, they are found to be associated with high-speed stream with southward interplanetary magnetic field, which is enhanced by a suitably orientated By component.It is further found that the flux distributions of the double-belt structure can be fitted well with a simply exponential decay function of L?. Based on the radiation belt content index, the proportion of the total number of 1.5-6.0 MeV electrons inside the position of maximum fluxes to that outside the maximum fluxes keeps rising during the double-belt period, which implies that the acceleration mainly occurs at regions inside the location of maximum fluxes. We suggest that the plasmapause and the strong wave-particle interactions with VLF and ULF waves near it play an important role in the development of the double-belt structures.

Yuan, Chongjing; Zong, Qiugang

2013-10-01

190

3D MHD Simulation of CME Propagation from Solar Corona to 1 AU  

Microsoft Academic Search

We present a three-dimensional (3D) numerical ideal magnetohydrodynamics (MHD) model describing the time-dependent expulsion of a CME from the solar corona propagating all the way to 1 A.U.. The simulations are performed using the BATS-R-US (Block Adaptive Tree Solarwind Roe Upwind Scheme) code. We begin by developing a global steady-state model of the corona that possesses high-latitude coronal holes and

W. B. Manchester; I. Roussev; M. Opher; T. Gombosi; D. Dezeeuw; G. Toth; I. Sokolov; K. Powell

2002-01-01

191

Charge state composition in coronal hole and CME related solar wind: Latitudinal variations observed by Ulysses and WIND  

NASA Technical Reports Server (NTRS)

Iron charge states in recurrent coronal hole-associated solar wind flows are obtained in the ecliptic by WIND/SMS, while measurements of iron and silicon from the polar coronal holes are available from Ulysses/SWICS. Ulysses/SWICS also provides ion composition of coronal mass ejection (CME)-related solar wind. Both coronal hole-associated and CME-related solar wind charge charges show heliographic latitudinal variations.

Galvin, A. B.; Gloeckler, G.

1997-01-01

192

Relating CME Shock Front Observations to their In-Situ Signatures  

NASA Astrophysics Data System (ADS)

When a fast Coronal Mass Ejection strikes the Earth, it will often be preceded by a shock front. By studying the propagation of these shock fronts in the Heliosphere and the evolution of the standoff distance between the ejecta front and the shock front using white light observations from the SOHO and STEREO Spacecrafts improvements can be made to predictions of shock and CME arrival at the Earth and to the theoretical modeling of how these shocks are driven. These results are further improved by comparing shock and CME propagation as measured in the Heliosphere to in-situ solar wind signatures at 1 AU obtained from the ACE satellite. For this study, multiple events have been tracked through the Heliosphere and linked with their arrival at the Earth. Of the events presented, the April 03, 2010 CME shows a particularly strong correlation in both arrival time and standoff distance as measured from observations and in-situ signatures showing that information obtained from white light images can be used to predict the arrival of shocks at the Earth, which has important implications for space weather forecasting.

Hess, Phillip; Zhang, J.

2012-05-01

193

CME-Sheath and Shock Heating by Surface Alfven Wave Dissipation in the Lower Corona  

NASA Astrophysics Data System (ADS)

We use the new solar corona component of the Space Weather Modeling Framework (van der Holst et al. 2010), in which the Alfven wave energy evolution is coupled self-consistently to the magnetohydrodynamic equations, to study the evolution of a coronal mass ejection (CME) and the shock it drives in the lower corona (2-8Rs). In this solar wind model, the wave pressure gradient accelerates the wind, and wave dissipation heats the wind. Kolmogorov-like dissipation and surface Alfven wave damping are considered for the dissipation of the waves (Evans et al. 2011). We use a modified Titov-Demoulin flux rope to initiate an eruption, and include magnetogram data from CR2029 (May 2005) as a boundary condition for the coronal magnetic field. Synthetic white light images from the simulation are used to determine the lateral expansion. We show that the expansion of the flux rope leads to the concentration of wave energy at the shock and in the sheath region. The expansion also creates a piled-up compression (PUC) region of plasma density at the back of the sheath, strongest at the flanks of the CME. The wave energy concentrated at the shock and sheath is dissipated by surface Alfven wave damping due to the density gradients, which heats the sheath. We present analysis of the momentum exchange between the solar wind and the waves, and discuss the effect of wave dissipation on the CME evolution.

Evans, R.; Opher, M.; van der Holst, B.

2011-12-01

194

Numerical Simulation of Multiple-CME Events in 2011-2013  

NASA Astrophysics Data System (ADS)

The ENLIL-based heliospheric modeling system enables faster-than-real time simulations of corotating and transient disturbances. This hybrid system does not simulate origin of coronal mass ejections (CMEs) but uses appearance in coronagraphs, its geometric and kinematic parameters, and launches a CME-like structure into the solar wind computed using the Wang-Sheeley-Arge (WSA) coronal model. Propagation and interaction in the heliosphere is solved by a 3-D magnetohydrodynamic (MHD) code. In this presentation, we introduce the recent improvements that support modeling of the evolving background solar wind and modeling of multiple-CME events. These enhancements are needed especially for simulations of complex scenarios of multiple-transients interacting with each other and with corotating solar wind stream structures. We simulated over 700 CMEs in 2011-2013 to validate and calibrate new modeling system, and we will show examples of multi-CME events during August 2010. March 2012, and July 2012 periods of enhanced solar activity. We will present results of numerical simulations and compare them with remote white-light observations, with in-situ measurements of plasma parameters, and with detection of solar energetic particles (SEPs) at various spacecraft.

Odstrcil, Dusan; Jian, Lan; Luhmann, Janet; Mays, Leila; Taktakishvili, Aleksandre; Xie, Hong

2014-05-01

195

Great Expectations: How STEREO Data Will Impact the Art of CME Modeling  

NASA Astrophysics Data System (ADS)

Driven by modern space-based solar and solar-wind observations, three-dimensional (3D) models of coronal mass ejections (CMEs), both numerical magnetohydrodynamic[1-4] and semi-analytical[5-7], have produced many exciting results. From among the current avenues of model-driven CME research, we shall highlight two areas where STEREO data might be expected to have a significant impact: 1) the near-sun geometrical relationship between the CME, the embedded prominence, and the underlying magnetic structure, and 2) the morphology and dynamics of erupting flux-ropes in the interplanetary medium, especially halo CMEs. We shall discuss the expected impact of STEREO data on "state of the art", model-driven CME research. Supported by ONR and NASA [1] Roussev et al. 2003, ApJ, 588, L45 [2] Amari et al. 2003, ApJ, 595, 1231 [3] Lynch et al. 2004, ApJ, 617, 589 [4] Manchester et al. 2004, JGR, 109, doi:10.1029/2003JA010150 [5] Chen 1996, JGR, 101, 27499 [6] Gibson and Low 2000, JGR, 105, 18187 [7] Chen and Krall 2003, JGR, 108, doi:10.1029/2003JA009849

Krall, J.

2005-05-01

196

Heliospheric ion energization due to emerging CME shocks  

NASA Astrophysics Data System (ADS)

Formation of inhomogeneous electromagnetic structures with gradients in magnetic field and intrinsic electric fields is commonly observed in magnetized plasmas. Heliospheric plasmas are susceptible to formation of localized, supersonically propagating electromagnetic inhomogeneities. Coronal relaxation may result in an emergence close to solar surface of a shock wave which traverses significant parts of the heliosphere. Shocks of solar origin may accelerate ions to high energies, and some of these ions can be trapped in quasi-stable orbits of planetary magnetospheres. The observationally deduced ion acceleration close to the Sun, at low Mach numbers and low turbulence levels, poses a dilemma regarding the energization mechanism. When the magnetic ramp of an obliquely propagating electromagnetic substructure narrows to a size of a fraction of ion skin depth, as conjectured during merging of successively propagating shocks, the trajectories of some ions exhibit strongly nonadiabatic characteristics. Subset of ions is energized while surfing along the shock due to the combined forces of magnetic fields and cross-shock electric potential gradient, forming a high-energy tail. This tail may be additionally accelerated after traversing the shock multiple times as a result of scattering and reflection due to Alfvenic wave diffusion. We follow the orbits of seed ions in a presence of a stationary, fluid-based, self-consistent model, and investigate their behavior for a variety of plasma parameters and geometries. The results indicate that (1) the energization of ions for low Mach numbers, as observed for emerging shocks close to the Sun, depends crucially on the narrowness of the electromagnetic structures, (2) the sufficiently narrow heliospheric structure can energize thermal protons and a subset of rare ions which were enriched due to impulsive coronal processes, (3) the energization is sensitive to the pitch angle of the seed population, indicating dependence on the geometry of the shock-plasma flow system, and (4) the preacceleration by surfing mechanism is a prerequisite for an additional energization due to diffusive shock acceleration. We conclude that the best configuration for an effective acceleration due to an emerging shock at small heliocentric distances and low Mach number consists of a narrow electromagnetic substructure which energizes heliospheric thermal protons directly from their thermal level, as well as trace elements which enrich the seed population due to previous coronal processes. The narrowness of the shock or its substructure and the surfing mechanism may help in explaining the observed energization when other mechanisms become inefficient due to an insufficient level of the turbulence. The energetic ion populations may have a direct profound impact on human space exploration.

Roth, I.; Bale, S. D.

2006-07-01

197

Quasi-periodic Fast-mode Magnetosonic Wave Trains Inside and Outside CME Bubbles Detected by SDO/AIA  

NASA Astrophysics Data System (ADS)

Quasi-periodic fast-mode magnetosonic wave trains both inside and outside expanding CME bubbles have recently been discovered by SDO/AIA (Liu et al. 2011, 2012; Shen & Liu 2012). In general, a wave train inside a CME bubble originates from a flare site and propagates along a funnel of coronal loops at typically 1000-2000 km/s (Ofman et al. 2011). A wave train outside a CME usually originates from a CME flank and propagates in the low corona along the solar surface following the leading front of a global EUV wave at typically 500-1000 km/s. The former is primarily seen in the cooler 171 Angstrom channel with a characteristic temperature of 0.8 MK, while the latter is pronounced in the hotter 193 and 211 Angstrom channels of typically 1.6-2.0 MK. What is the relationship between the two types of wave trains? Why do they appear differently in location and wavelength (temperature)? To answer these questions, we report here for the first time the evidence that the wave train beyond the CME bubble is the continuation of the same wave train along the funnel within the CME. The continuous deceleration of the waves is consistent with the expected decrease of the local fast-mode speed with distance from the active region (e.g., Ofman et al. 2011; Downs et al. 2012). There is an abrupt change of the wave speed at the topological interface where the expanding CME flank is located, indicative of contrasting magnetic and plasma conditions, which can give rise to different (fast-mode) speeds and wavelength (temperature) dependent appearances of these wave trains.Abstract (2,250 Maximum Characters): Quasi-periodic fast-mode magnetosonic wave trains both inside and outside expanding CME bubbles have recently been discovered by SDO/AIA (Liu et al. 2011, 2012; Shen & Liu 2012). In general, a wave train inside a CME bubble originates from a flare site and propagates along a funnel of coronal loops at typically 1000-2000 km/s (Ofman et al. 2011). A wave train outside a CME usually originates from a CME flank and propagates in the low corona along the solar surface following the leading front of a global EUV wave at typically 500-1000 km/s. The former is primarily seen in the cooler 171 Angstrom channel with a characteristic temperature of 0.8 MK, while the latter is pronounced in the hotter 193 and 211 Angstrom channels of typically 1.6-2.0 MK. What is the relationship between the two types of wave trains? Why do they appear differently in location and wavelength (temperature)? To answer these questions, we report here for the first time the evidence that the wave train beyond the CME bubble is the continuation of the same wave train along the funnel within the CME. The continuous deceleration of the waves is consistent with the expected decrease of the local fast-mode speed with distance from the active region (e.g., Ofman et al. 2011; Downs et al. 2012). There is an abrupt change of the wave speed at the topological interface where the expanding CME flank is located, indicative of contrasting magnetic and plasma conditions, which can give rise to different (fast-mode) speeds and wavelength (temperature) dependent appearances of these wave trains.

Liu, Wei; Ofman, L.; Downs, C.; Title, A. M.

2013-07-01

198

Delivery methods for LVSD systems  

NASA Astrophysics Data System (ADS)

In this paper we present formats and delivery methods of Large Volume Streaming Data (LVSD) systems. LVSD systems collect TBs of data per mission with aggregate camera sizes in the 100 Mpixel to several Gpixel range at temporal rates of 2 - 60 Hz. We present options and recommendations for the different stages of LVSD data collection and delivery, to include the raw (multi-camera) data, delivery of processed (stabilized mosaic) data, and delivery of user-defined region of interest windows. Many LVSD systems use JPEG 2000 for the compression of raw and processed data. We explore the use of the JPEG 2000 Interactive Protocol (JPIP) for interactive client/server delivery to thick-clients (desktops and laptops) and MPEG-2 and H.264 to handheld thin-clients (tablets, cell phones). We also explore the use of 3D JPEG 2000 compression, defined in ISO 15444-2, for storage and delivery as well. The delivery of raw, processed, and region of interest data requires different metadata delivery techniques and metadata content. Beyond the format and delivery of data and metadata we discuss the requirements for a client/server protocol that provides data discovery and retrieval. Finally, we look into the future as LVSD systems perform automated processing to produce "information" from the original data. This information may include tracks of moving targets, changes of the background, snap shots of targets, fusion of multiple sensors, and information about "events" that have happened.

Kasner, James H.; Brower, Bernard V.

2011-05-01

199

Magnetic Field Diffusion During the CME-Magnetosphere Interaction with Cluster Measurement on 6 November, 2001  

NASA Astrophysics Data System (ADS)

Intense geomagnetic storms are usually caused by the CME-magnetosphere interaction Up to now there are only very few in situ measurements with respect to the details of interactions of interplanetary CME ICME and magnetosphere In this paper we report such a fortuitous observation made by Cluster four spacecraft At 16 35 UT on Nov 4 2001 LASCO SOHO observed an Earth-direction halo CME The associated ICME caused an intense magnetic storm with Dst -300 nT on Nov 6-8 2001 During the process of ICME-magnetosphere interaction since 01 54 UT on Nov 6 the Cluster spacecraft located near in the near-tail dawn magnetopause -9 6 15 0 2 2 Re in GSM coordinates more than five hours meandering back and forth four times between the ICME and the magnetosphere The constellation observed part process of the interaction between the ICME and the flank of magnetosphere During the magnetopause inbound crossings after 02 26 UT the plasma temperature hot ion density and fluxes of energetic ionsalways varied sharply but the magnetic field varied continually and smoothly and almost kept the order of 100 nT The primary analysis shows that the large magnetic field structures are generated by the reconnection between ICME and magnetosphere and move anti-sunward with the solar wind driving It is very surprised that in this event contrary to the usually magnetic frozen-in frame the Cluster data shows that most part of the large magnetospheric magnetic field come from the ICME via magnetic diffusion in more than about half hours We estimated the time scale of magnetic

Xiao, C. J.; Song, L. T.; Pu, Z. Y.; Liu, Z. X.; Daly, P.; Balogh, A.; Reme, H.

200

Speed evolution of CME/shocks using multi-spacecraft observations of type II radio bursts: A case study  

NASA Astrophysics Data System (ADS)

We present a study which focuses on the speed evolution of a coronal mass ejection (CME)/shock associated with a type II radio burst observed on January 25, 2007. The type II burst feature had a multi-spacecraft coverage, being detected by the Wind/WAVES and the STEREO/WAVES radio instruments in the frequency range of 14 MHz to 90 kHz. The CME associated with the type II radio burst was observed by the SOHO/LASCO and the STEREO/SECCHI coronographs. Ground-based radio observations of the metric type II burst counterpart were obtained by the Bruny Island Radio Spectrometer (BIRS) in the frequency range of 40 MHz to 25 MHz. We analyzed the combined white-light and radio observations to infer the speed evolution of the CME/shock event. The CME/shock speed from the different data sets shows a significant deceleration near to the Sun followed by a slow and gradual deceleration in the interplanetary medium, which is consistent with the expected evolution of fast CME/shocks. Multi-spacecraft and combined white-light and radio observations are important to gain insight into the tracking of solar transients which propagate in the inner heliosphere.

Manuel-Hernandez, T.; Aguilar-Rodriguez, E.; Gonzalez-Esparza, J. A.; Ontiveros, V.

2013-06-01

201

The Driving Magnetic Field and Reconnection in CME/Flare Eruptions and Coronal Jets  

NASA Technical Reports Server (NTRS)

Signatures of reconnection in major CME (coronal mass ejection)/flare eruptions and in coronal X-ray jets are illustrated and interpreted. The signatures are magnetic field lines and their feet that brighten in flare emission. CME/flare eruptions are magnetic explosions in which: 1. The field that erupts is initially a closed arcade. 2. At eruption onset, most of the free magnetic energy to be released is not stored in field bracketing a current sheet, but in sheared field in the core of the arcade. 3. The sheared core field erupts by a process that from its start or soon after involves fast "tether-cutting" reconnection at an initially small current sheet low in the sheared core field. If the arcade has oppositely-directed field over it, the eruption process from its start or soon after also involves fast "breakout" reconnection at an initially small current sheet between the arcade and the overarching field. These aspects are shown by the small area of the bright field lines and foot-point flare ribbons in the onset of the eruption. 4. At either small current sheet, the fast reconnection progressively unleashes the erupting core field to erupt with progressively greater force. In turn, the erupting core field drives the current sheet to become progressively larger and to undergo progressively greater fast reconnection in the explosive phase of the eruption, and the flare arcade and ribbons grow to become comparable to the pre-eruption arcade in lateral extent. In coronal X-ray jets: 1. The magnetic energy released in the jet is built up by the emergence of a magnetic arcade into surrounding unipolar "open" field. 2. A simple jet is produced when a burst of reconnection occurs at the current sheet between the arcade and the open field. This produces a bright reconnection jet and a bright reconnection arcade that are both much smaller in diameter that the driving arcade. 3. A more complex jet is produced when the arcade has a sheared core field and undergoes an ejective eruption in the manner of a miniature CME/flare eruption. The jet is then a combination of a miniature CME and the products of more widely distributed reconnection of the erupting arcade with the open field than in simple jets.

Moore, Ronald L.

2010-01-01

202

Comparison of the WSA-ENLIL model with three CME cone types  

NASA Astrophysics Data System (ADS)

We have made a comparison of the CME-associated shock propagation based on the WSA-ENLIL model with three cone types using 29 halo CMEs from 2001 to 2002. These halo CMEs have cone model parameters as well as their associated interplanetary (IP) shocks. For this study we consider three different cone types (an asymmetric cone model, an ice-cream cone model and an elliptical cone model) to determine 3-D CME parameters (radial velocity, angular width and source location), which are the input values of the WSA-ENLIL model. The mean absolute error (MAE) of the arrival times for the asymmetric cone model is 10.6 hours, which is about 1 hour smaller than those of the other models. Their ensemble average of MAE is 9.5 hours. However, this value is still larger than that (8.7 hours) of the empirical model of Kim et al. (2007). We will compare their IP shock velocities and densities with those from ACE in-situ measurements and discuss them in terms of the prediction of geomagnetic storms.Abstract (2,250 Maximum Characters): We have made a comparison of the CME-associated shock propagation based on the WSA-ENLIL model with three cone types using 29 halo CMEs from 2001 to 2002. These halo CMEs have cone model parameters as well as their associated interplanetary (IP) shocks. For this study we consider three different cone types (an asymmetric cone model, an ice-cream cone model and an elliptical cone model) to determine 3-D CME parameters (radial velocity, angular width and source location), which are the input values of the WSA-ENLIL model. The mean absolute error (MAE) of the arrival times for the asymmetric cone model is 10.6 hours, which is about 1 hour smaller than those of the other models. Their ensemble average of MAE is 9.5 hours. However, this value is still larger than that (8.7 hours) of the empirical model of Kim et al. (2007). We will compare their IP shock velocities and densities with those from ACE in-situ measurements and discuss them in terms of the prediction of geomagnetic storms.

Jang, Soojeong; Moon, Y.; Na, H.

2013-07-01

203

Characteristics of Polar Cap Patches and Shear Flows Inferred from GPS Scintillation Spectra following the CME Impact on 22 January 2012  

NASA Astrophysics Data System (ADS)

Polar cap patches are localized enhancements in ionospheric density which originate from solar EUV ionization on the dayside, enter the polar cap at the dayside cusp, convect anti-sunward at km/s velocities, and then exit the polar cap near midnight to merge with sunward returning flow patterns. Plasma irregularities associated with patches are the leading cause of high-latitude scintillations at L-band, and fast shear flows near the dayside cusp are thought to be integral to patch formation. In this paper, we report on the characteristics of polar cap patches and fast flows inferred from the spectra of GPS scintillations recorded at Longyearbyen, Svalbard, following the CME impact on 22 January 2012. Following the CME impact, elevated GPS TEC values indicate the passage of patches through the cusp between 11-15 MLT, accompanied by significant GPS phase scintillations (?? ~ 0.5 radians) but minimal amplitude scintillations (S4 < 0.05). We demonstrate that the relative lack of amplitude scintillations is consistent with Fresnel filtering of the path integrated irregularity spectrum with a relatively high cutoff frequency (8 Hz). This filtering is consistent with weak scatter of the satellite signals by irregularities scanning past the ray path with a velocity approaching 3 km/s. We exploit the Fresnel filtering effect and introduce a technique to deduce the flow velocity by reconciling the phase and amplitude spectra with weak scatter theory. We apply this technique to investigate the noontime entrance of patches into the dayside cusp and the midnight exit of patches from the polar cap. The scan velocity increased from about 500-1000 m/s following the initial CME impact at ~6:00 UT, to sustained velocities between 1500-3000 m/s measured by GPS satellites whose ray paths intersected fast plasma flows near the cusp. In this sector, the phase spectral index (p) generally ranged between 2.4-2.8, with a tendency for somewhat larger values when the flow was faster. Weaker irregularities were detected in the outflow sector between 20-24 MLT, when p generally ranged from 2.6-3.0. The scan velocities measured in the outflow sector were slower, generally between 400-600 m/s. These velocity estimates compare favorably with ion drift measurements made by the DMSP satellites. Our analysis technique is automated and could potentially enable continuous monitoring of flow patterns in the polar cap using a relatively inexpensive GPS scintillation monitor. These measurements could then complement measurements from space-based platforms that sample the polar cap only intermittently and incoherent scatter radars which provide excellent diagnostics but cannot operate continuously.

Carrano, C. S.; Basu, S.; MacKenzie, E.; Groves, K. M.; Pedersen, T. R.; Holmes, J. M.

2012-12-01

204

The Width of a Solar Coronal Mass Ejection and the Source of the Driving Magnetic Explosion: A Test of the Standard Scenario for CME Production  

NASA Technical Reports Server (NTRS)

We show that the strength (B(sub F1are)) of the magnetic field in the area covered by the flare arcade following a CME-producing ejective solar eruption can be estimated from the final angular width (Final Theta(sub CME)) of the CME in the outer corona and the final angular width (Theta(sub Flare)) of the flare arcade: B(sub Flare) approx. equals 1.4[(Final Theta(sub CME)/Theta(sub Flare)] (exp 2)G. We assume (1) the flux-rope plasmoid ejected from the flare site becomes the interior of the CME plasmoid; (2) in the outer corona (R > 2 (solar radius)) the CME is roughly a "spherical plasmoid with legs" shaped like a lightbulb; and (3) beyond some height in or below the outer corona the CME plasmoid is in lateral pressure balance with the surrounding magnetic field. The strength of the nearly radial magnetic field in the outer corona is estimated from the radial component of the interplanetary magnetic field measured by Ulysses. We apply this model to three well-observed CMEs that exploded from flare regions of extremely different size and magnetic setting. One of these CMEs was an over-and-out CME, that is, in the outer corona the CME was laterally far offset from the flare-marked source of the driving magnetic explosion. In each event, the estimated source-region field strength is appropriate for the magnetic setting of the flare. This agreement (1) indicates that CMEs are propelled by the magnetic field of the CME plasmoid pushing against the surrounding magnetic field; (2) supports the magnetic-arch-blowout scenario for over-and-out CMEs; and (3) shows that a CME's final angular width in the outer corona can be estimated from the amount of magnetic flux covered by the source-region flare arcade.

Moore, Ronald L.; Sterling, Alphonse C.; Suess, Steven T.

2007-01-01

205

Observations and analysis of the April 9, 2008 CME using STEREO, Hinode TRACE and SoHO data  

NASA Astrophysics Data System (ADS)

On April 9, 2008 a CME originating from an active region behind the limb was well-observed by STEREO, Hinode, TRACE and SoHO. Several interesting features connected to this eruption were observed. (1) The interaction of the CME with open field lines from a nearby coronal hole appeared to cause an abrupt change in the direction of the CME ejecta. (2) The prominence material was heated, as evidenced by a change from absorption to emission in the EUV wavelengths. (3) Because the active region was behind the limb, the X-Ray Telescope on Hinode was able to take long enough exposure times to observe a faint current- sheet like structure, and it was able to monitor the dynamics of the plasma surrounding this structure. This event is also being studied in the context of activity that occurred during the Whole Heliosphere Interval (WHI).

Reeves, K. K.; Patsourakos, S.; Stenborg, G.; Miralles, M.; Deluca, E.; Forbes, T.; Golub, L.; Kasper, J.; Landi, E.; McKenzie, D.; Narukage, N.; Raymond, J.; Savage, S.; Su, Y.; van Ballegooijen, A.; Vourlidas, A.; Webb, D.

2008-12-01

206

Solar Source and CME Properties of Solar Cycle 23 Ground Level Enhancement Events  

NASA Technical Reports Server (NTRS)

Solar cycle 23 witnessed the most complete set of observations of coronal mass ejections (CMEs) associated with the Ground Level Enhancement (GLE) events. GLE events are extreme cases of solar energetic particle (SEP) events in that the energetic particles penetrate Earth's neutral atmosphere to be detected by neutron monitors. In this paper we present the CME and their source properties that seem to be equally extreme. These observations are consistent with the idea that the GLE particles are accelerated in the same way as the regular SEP events by CME-driven shocks. While we cannot rule out the possibility of the presence of a flare component during GLE events, we can definitely say that a shock component is present in all the GLE events. We provide additional information on the GLE-associated type II radio bursts, complex type III radio bursts, and soft X-ray flares, which are not very different from those associated with large SEP events. Finally we compare the properties of GLEassociated CMEs in cycle 23 with those in cycle 22.

Gopalswamy, Nat; Xie, H.; Yashiro, S.; Akiyama, S.; Makela, P.; Usoskin, I.

2010-01-01

207

CME - Solar Wind interaction using remote and in-situ observations  

NASA Astrophysics Data System (ADS)

Coronal mass ejections (CMEs) are the main drivers of Space Weather. Accurate forecasting of their likely geo-effectiveness requires accurate tracking of their morphological and kinematical evolution throughout the interplanetary medium. However, single view-point observations depend on strong assumptions to model the development of the CME; the most common hypotheses are those of radial propagation and self-similar expansion. The use of different view-points show that, at least for some cases, those assumptions may not be valid. Analyses of remote sensing and in-situ data show signatures of strong deflection, over-expansion and/or large deformation. These behaviors could hide effects as rotation, deviation from radial propagation, or interaction with other magnetic obstacles. Understanding the 3D development and evolution of CME features is therefore of utmost importance to help establish the connection between remote and in-situ observations, and hence improve forecasting of Space Weather. In this work, we present the analysis of a set of selected events exhibiting clear signatures of deflection. With the help of remote imaging observations provided by the SOHO, STEREO and SDO missions, and in-situ measurements recorded by Wind, ACE, and Messenger. We show that such signatures are evidence of hidden effects such as rotation, changes in the direction of propagation, and/or interaction with other magnetic obstacles.

Nieves-Chinchilla, T.; Stenborg, G.; Vourlidas, A.; Savani, N. P.; Hidalgo, M. A.; Vena, L.; Szabo, A.; Colaninno, R. C.

2013-05-01

208

A decade of coronagraphic and spectroscopic studies of CME-driven shocks  

NASA Astrophysics Data System (ADS)

Shocks driven by Coronal Mass Ejections (CMEs) are primary agents of space weather. They can accelerate particles to high energies and can compress the magnetosphere thus setting in motion geomagnetic storms. For many years, these shocks were studied only in-situ when they crossed over spacecraft or remotely through their radio emission spectra. Neither of these two methods provides information on the spatial structure of the shock nor on its relationship to its driver, the CME. In the last decade, we have been able to not only image shocks with coronagraphs but also measure their properties remotely through the use of spectroscopic and image analysis methods. Thanks to instrumentation on STEREO and SOHO we can now image shocks (and waves) from the low corona, through the inner heliosphere, to Earth. Here, we review the progress made in imaging and analyzing CME-driven shocks and show that joint coronagraphic and spectrscopic observations are our best means to understand shock physics close to the Sun.

Vourlidas, Angelos; Bemporad, Alessandro

2012-05-01

209

The Seed Population for Energetic Particles Accelerated by CME-Driven Shocks  

NASA Astrophysics Data System (ADS)

Understanding properties of solar energetic particle (SEP) events associated with coronal mass ejections has been identified as a key problem in solar-terrestrial physics. Although recent CME shock acceleration models are highly promising, detailed agreement between theoretical predictions and observations has remained elusive. Recent observations from ACE have shown substantial enrichments in the abundances of 3He and He+ ions which are extremely rare in the thermal solar wind plasma. Consequently, these ions act as tracers of their source material, i.e., 3He ions are flare suprathermals and He+ ions are interstellar pickup ions. The average heavy ion composition also exhibits unsystematic differences when compared with the solar wind values, but correlates significantly with the ambient suprathermal material abundances. Taken together these results provide compelling evidence that CME-driven shocks draw their source material from the ubiquitous but largely unexplored suprathermal tail rather than from the more abundant solar wind peak. However, the suprathermal energy regime has many more contributors and exhibits much larger variability than the solar wind, and as such needs to be investigated more thoroughly. Answers to fundamental new questions regarding the preferred injection of the suprathermal ions, the spatial and temporal dependence of the various sources, and the causes of their variability and their effects on the SEP properties are needed to improve agreement between the simulations and observations.

Desai, M. I.; Mason, G. M.; Mazur, J. E.; Dwyer, J. R.

2006-06-01

210

Superposed epoch analysis of ion temperatures during CME- and CIR/HSS-driven storms  

NASA Astrophysics Data System (ADS)

The NASA Two Wide-angle Imaging Neutral atom Spectrometers (TWINS) Mission provides a global view of the magnetosphere with near-continuous coverage. Utilizing a novel technique to calculate ion temperatures from the TWINS energetic neutral atom (ENA) measurements, we generate ion temperature maps of the magnetosphere. These maps can be used to study ion temperature evolution during geomagnetic storms. A superposed epoch analysis of the ion temperature evolution during 48 storms will be presented. Zaniewski et al. [2006] performed a superposed epoch analysis of ion temperatures by storm interval using data from the MENA instrument on the IMAGE mission, demonstrating significant dayside ion heating during the main phase. The TWINS measurements provide more continuous coverage and improved spatial and temporal resolution. Denton and Borovsky [2008] noted differences in ion temperature evolution at geosynchronous orbit between coronal mass ejection (CME)- and corotating interaction region (CIR)/high speed stream (HSS)- driven storms. Using our global ion temperature maps, we have found consistent results for select individual storms [Keesee et al., 2012]. We will present superposed epoch analyses for the subgroups of CME- and CIR/HSS-driven storms to compare global ion temperature evolution during the two types of storms.

Keesee, A. M.; Scime, E. E.

2012-12-01

211

The Divergence of CME and Sunspot Number Rates During Solar Cycle 24  

NASA Astrophysics Data System (ADS)

In the previous three solar cycles the frequency of occurrence of CMEs observed in white light has closely tracked the solar cycle in both phase and amplitude, varying by an order of magnitude over the cycle. LASCO has now observed the entire solar Cycle 23 and continues to observe through the current rise and maximum phases of Cycle 24. Cycle 23 had an unusually long decline and extended minimum. During this period we have been able to image and count CMEs in the heliosphere, and can determine rates from both LASCO and STEREO SECCHI (since 2007) coronagraphs and from the Solar Mass Ejection Imager (SMEI - since 2003) and the SECCHI Heliospheric Imagers in the heliosphere. Manual rates estimated by observers are now supplemented by counts from identifications made by automatic programs, such as contained in the SEEDS, CACTus and ARTEMIS catalogs. Since the cycle 23/24 minimum, the CME and sunspot number rates have diverged, with similar cycle 23/24 rise and peak CME rates but much lower SSN rates in this cycle. We will discuss these rate estimates and their implications for the evolution of the global solar magnetic field.

Webb, David F.; St. Cyr, Orville Chris; Xie, Hong; Kuchar, Thomas Andrew

2014-06-01

212

PROPAGATION AND EVOLUTION OF THE JUNE 1st 2008 CME IN THE INTERPLANETARY MEDIUM  

NASA Astrophysics Data System (ADS)

In this work we present a study of the coronal mass ejection (CME) of June 1st of 2008 in the interplanetary medium. This event has been extensively studied by others because of its favorable geometry and the possible consequences of its peculiar initiation for space weather forecasting. We show an analysis of the evolution of the CME in the interplanetary medium in order to shed some light on the propagation mechanism of the ICME. We have determined the typical shock associated characteristics of the ICME in order to understand the propagation properties. Using two different non force-free models of the magnetic cloud allows us to incorporate expansion of the cloud. We use in-situ measurements from STEREO B/IMPACT to characterize the ICME. In addition, we use images from STEREO A/SECCHI-HI to analyze the propagation and visual evolution of the associated flux rope in the interplanetary medium. We compare and contrast these observations with the results of the analytical models.

Nieves-Chinchilla, T.; Lamb, D. A.; Davila, J. M.; Vinas, A. F.; Moestl, C.; Hidalgo, M. A.; Farrugia, C. J.; Malandraki, O.; Dresing, N.; Gómez-Herrero, R.

2009-12-01

213

The Recovery of CME-Related Dimmings and the ICME's Enduring Magnetic Connection to the Sun  

NASA Astrophysics Data System (ADS)

It is generally accepted that transient coronal holes (TCHs, dimmings) correspond to the magnetic footpoints of CMEs that remain rooted in the Sun as the CME expands out into the interplanetary space. However, the observation that the average intensity of the 12 May 1997 dimmings recover to their pre-eruption intensity in SOHO/EIT data within 48 hours, whilst suprathermal unidirectional electron heat fluxes are observed at 1 AU in the related ICME more than 70 hours after the eruption, leads us to question why and how the dimmings disappear whilst the magnetic connectivity is maintained. We also examine two other CME-related dimming events: 13 May 2005 and 6 July 2006. We study the morphology of the dimmings and how they recover. We find that, far from exhibiting a uniform intensity, dimmings observed in SOHO/EIT data have a deep central core and a more shallow extended dimming area. The dimmings recover not only by shrinking of their outer boundaries but also by internal brightenings. We quantitatively demonstrate that the model developed by Fisk and Schwadron ( Astrophys. J. 560, 425, 2001) of interchange reconnections between “open” magnetic field and small coronal loops is a strong candidate for the mechanism facilitating the recovery of the dimmings. This process disperses the concentration of “open” magnetic field (forming the dimming) out into the surrounding quiet Sun, thus recovering the intensity of the dimmings whilst still maintaining the magnetic connectivity to the Sun.

Attrill, G. D. R.; van Driel-Gesztelyi, L.; Démoulin, P.; Zhukov, A. N.; Steed, K.; Harra, L. K.; Mandrini, C. H.; Linker, J.

2008-11-01

214

Ion acceleration at CME-driven shocks near the Earth and the Sun  

SciTech Connect

We compare the behavior of heavy ion spectra during an Energetic Storm Particle (ESP) event that exhibited clear evidence of wave excitation with that observed during an intense, large gradual Solar Energetic Particle (SEP) event in which the associated <0.2 MeV/nucleon ions are delayed >12 hr. We interpret that the ESP event is an example of the first-order Fermi acceleration process where enhancements in the magnetic field power spectral densities around local ion cyclotron frequency {nu}{sub pc} indicate the presence of Alfven waves excited by accelerated protons streaming away from the in-situ interplanetary shock. The softening or unfolding of the CNO energy spectrum below {approx}200 keV/nucleon and the systematic organization of the Fe and O spectral roll-overs with the E/q ratio during the ESP event are likely due to M/Q-dependent trapping and scattering of the heavy ions by the proton-excited waves. Based on striking similarities in the spectral behavior observed upstream of both, the ESP and the SEP event, we suggest that coupling between proton-generated Alfven waves and energetic ions is also operating at the distant CME shock during the large, gradual SEP event, thereby providing us with a new, powerful tool to remotely probe the roles of shock geometries and wave-particle interactions at near-Sun CME-driven shocks.

Desai, Mihir; Dayeh, Maher; Ebert, Robert; Smith, Charles; Mason, Glenn; Li, G. [Southwest Research Institute, 6220 Culebra Road, San Antonio, Texas, 78238 (United States); University of New Hampshire, Durham, New Hampshire, 03824 (United States); Applied Physics Laboratory, Johns Hopkins University, Laurel, Maryland, 20724 (United States); Center for Space Plasma and Aeronomic Research, University of Alabama, Huntsville, Al 35899 (United States)

2012-11-20

215

Physical differences between the initial phase of the formation of two types of coronal mass ejections  

NASA Astrophysics Data System (ADS)

Physical differences in the formation of "gradual" and "impulsive" coronal mass ejections (CMEs) at heights of h < 0.2 R ? just before and during the initial phase of their motion are studied using AIA/SDO ultraviolet data ( h is the altitude above the solar surface and R ? is the solar radius). The basic structure of a gradual CME is a magnetic rope located in the corona. During an hour or more preceding the initial phase, the magnetic rope demonstrates an increase in brightness and transverse size, first of the low, inner elements of the rope and then of elements in its outer envelope most distant from the Sun. The rope remains motionless during this time. The initial phase of a gradual CME begins from the motion of the magnetic rope's outer envelope, which further becomes the basis for the CME frontal structure. At this stage, the inner low elements of the rope remain almost motionless. The initial phase of an impulsive CME begins with the appearance near the photosphere of a cavity moving away from the Sun; the dynamics of this cavity probably correspond to a magnetic tube filled with cool plasma rising from beneath the photosphere. This magnetic tube collides with and drags arch structures, which initially block the tube's motion. These arch structures contribute to the CME formation, although the magnetic tube itself forms the basis of the CME.

Eselevich, V. G.; Eselevich, M. V.

2014-04-01

216

SCEC Community Modeling Environment (SCEC/CME) - Seismic Hazard Analysis Applications and Infrastructure  

NASA Astrophysics Data System (ADS)

The Southern California Earthquake Center (SCEC) has formed a Geoscience/IT partnership to develop an advanced information infrastructure for system-level earthquake science in Southern California. This SCEC/ITR partnership comprises SCEC, USC's Information Sciences Institute (ISI), the San Diego Supercomputer Center (SDSC), the Incorporated Institutions for Research in Seismology (IRIS), and the U.S. Geological Survey. This collaboration recently completed the second year in a five-year National Science Foundation (NSF) funded ITR project called the SCEC Community Modeling Environment (SCEC/CME). The goal of the SCEC/CME is to develop seismological applications and information technology (IT) infrastructure to support the development of Seismic Hazard Analysis (SHA) programs and other geophysical simulations. The SHA application programs developed by project collaborators include a Probabilistic Seismic Hazard Analysis system called OpenSHA [Field et al., this meeting]. OpenSHA computational elements that are currently available include a collection of attenuation relationships, and several Earthquake Rupture Forecasts (ERF's). Geophysicists in the collaboration have also developed Anelastic Wave Models (AWMs) using both finite-difference and finite-element approaches. Earthquake simulations using these codes have been run for a variety of earthquake sources. A Rupture Dynamic Model (RDM) has also been developed that couples a rupture dynamics simulation into an anelastic wave model. The collaboration has also developed IT software and hardware infrastructure to support the development, execution, and analysis of SHA programs. To support computationally expensive simulations, we have constructed a grid-based system utilizing Globus software [Kesselman et al., this meeting]. Using the SCEC grid, project collaborators can submit computations from the SCEC/CME servers to High Performance Computers at USC, NPACI and Teragrid High Performance Computing Centers. We have developed a SCEC Community Velocity Model server based on Internet standards (XML, SOAP, and WSDL) to provide access to the SCEC Community Velocity Model. We have also continued development of the SCEC Fault Information System (SCEC/FIS) to provide access to the SCEC Community Fault Model and the SCEC Fault Activity Database. Data generated and archived by the SCEC/CME is stored in a digital library system, the Storage Resource Broker (SRB) [Minster et al., this meeting]. This system provides a robust and secure system for maintaining the association between the data sets and their metadata. A browser-based computational pathway assembly web site has been developed [Gupta et al., this meeting]. Users can compose SHA calculations and call SCEC/CME computational programs to process the data and the output. By assembling a series of computational steps, users can develop complex computational pathways the validity of which can be verified with an ontology-based pathway assembly tool. Data visualization software developed by the collaboration to support analysis and validation of data sets includes 4D wave propagation visualization software based on OpenGL [Thiebaux et al., this meeting] and 3D Geowall-based visualization of earthquakes and faults.

Maechling, P. J.; Jordan, T. H.; Kesselman, C.; Moore, R.; Minster, B.; SCEC ITR Collaboration

2003-12-01

217

C-ME: A 3D Community-Based, Real-Time Collaboration Tool for Scientific Research and Training  

PubMed Central

The need for effective collaboration tools is growing as multidisciplinary proteome-wide projects and distributed research teams become more common. The resulting data is often quite disparate, stored in separate locations, and not contextually related. Collaborative Molecular Modeling Environment (C-ME) is an interactive community-based collaboration system that allows researchers to organize information, visualize data on a two-dimensional (2-D) or three-dimensional (3-D) basis, and share and manage that information with collaborators in real time. C-ME stores the information in industry-standard databases that are immediately accessible by appropriate permission within the computer network directory service or anonymously across the internet through the C-ME application or through a web browser. The system addresses two important aspects of collaboration: context and information management. C-ME allows a researcher to use a 3-D atomic structure model or a 2-D image as a contextual basis on which to attach and share annotations to specific atoms or molecules or to specific regions of a 2-D image. These annotations provide additional information about the atomic structure or image data that can then be evaluated, amended or added to by other project members.

Kolatkar, Anand; Kennedy, Kevin; Halabuk, Dan; Kunken, Josh; Marrinucci, Dena; Bethel, Kelly; Guzman, Rodney; Huckaby, Tim; Kuhn, Peter

2008-01-01

218

Relation Between the 3D-Geometry of the Coronal Wave and Associated CME During the 26 April 2008 Event  

NASA Technical Reports Server (NTRS)

We study the kinematical characteristics and 3D geometry of a large-scale coronal wave that occurred in association with the 26 April 2008 flare-CME event. The wave was observed with the EUVI instruments aboard both STEREO spacecraft (STEREO-A and STEREO-B) with a mean speed of approx 240 km/s. The wave is more pronounced in the eastern propagation direction, and is thus, better observable in STEREO-B images. From STEREO-B observations we derive two separate initiation centers for the wave, and their locations fit with the coronal dimming regions. Assuming a simple geometry of the wave we reconstruct its 3D nature from combined STEREO-A and STEREO-B observations. We find that the wave structure is asymmetric with an inclination toward East. The associated CME has a deprojected speed of approx 750 +/- 50 km/s, and it shows a non-radial outward motion toward the East with respect to the underlying source region location. Applying the forward fitting model developed by Thernisien, Howard, and Vourlidas we derive the CME flux rope position on the solar surface to be close to the dimming regions. We conclude that the expanding flanks of the CME most likely drive and shape the coronal wave.

Temmer, M.; Veronig, A. M.; Gopalswamy, N.; Yashiro, S.

2011-01-01

219

Evidence-based choices of physicians: a comparative analysis of physicians participating in Internet CME and non-participants  

PubMed Central

Background The amount of medical education offered through the Internet continues to increase, providing unprecedented access for physicians nationwide. However, the process of evaluating these activities is ongoing. This study is a continuation of an earlier report that found online continuing medical education (CME) to be highly effective in making evidence-based decisions. Methods To determine the effectiveness of 114 Internet CME activities, case vignette-based surveys were administered to U.S.-practicing physicians immediately following participation, and to a representative control group of non-participants. Survey responses were analyzed based on evidence presented in the content of CME activities. An effect size for each activity was calculated using Cohen's d to determine the amount of difference between the two groups in the likelihood of making evidence-based clinical decisions. Results In a sample of 17,142 U.S. physicians, of the more than 350,000 physicians who participated in 114 activities, the average effect size was 0.82. This indicates an increased likelihood of 48% that physicians participating in online activities were making clinical choices based on evidence. Conclusion Physicians who participated in online CME activities continue to be more likely to make evidence-based clinical choices than non-participants in response to clinical case vignettes.

2010-01-01

220

Comparison of CME radial velocities from a flux rope model and an ice cream cone model  

NASA Astrophysics Data System (ADS)

Coronal Mass Ejections (CMEs) on the Sun are the largest energy release process in the solar system and act as the primary driver of geomagnetic storms and other space weather phenomena on the Earth. So it is very important to infer their directions, velocities and three-dimensional structures. In this study, we choose two different models to infer radial velocities of halo CMEs since 2008 : (1) an ice cream cone model by Xue et al (2005) using SOHO/LASCO data, (2) a flux rope model by Thernisien et al. (2009) using the STEREO/SECCHI data. In addition, we use another flux rope model in which the separation angle of flux rope is zero, which is morphologically similar to the ice cream cone model. The comparison shows that the CME radial velocities from among each model have very good correlations (R>0.9). We will extending this comparison to other partial CMEs observed by STEREO and SOHO.

Kim, T.; Moon, Y.; Na, H.

2011-12-01

221

Long-term evaluation of recombinant human bone morphogenetic protein-2 induced bone formation with a biologic and synthetic delivery system  

Microsoft Academic Search

The efficacy of microspheres made of polylactic acid polyglycolic acid copolymer mixed with blood clot as a delivery system for recombinant human bone morphogenetic protein-2 (rhBMP-2) was evaluated and the long term behaviour of rhBMP-2 in rats was studied. Twenty micro grams of rhBMP-2 in 200 ?l carrier (blood coagulum and polylactic acid polyglycolic acid porous microspheres) were implanted subcutaneously

C Alpaslan; K Irie; K Takahashi; N Ohashi; H Sakai; T Nakajima; H Ozawa

1996-01-01

222

A solar type II radio burst from CME-coronal ray interaction:simultaneous radio and EUV imaging  

NASA Astrophysics Data System (ADS)

Simultaneous radio and extreme ultraviolet (EUV)/white-light imaging data are examined for a solar type II radio burst occurring on 2010 March 18 to deduce its source location. Using a bow-shock model, we reconstruct the 3-dimensional EUV wave front (presumably the type-II emitting shock) based on the imaging data of the two STEREO spacecraft. It is then combined with the Nan\\c{c}ay radio imaging data to infer the 3-dimensional position of the type II source. It is found that the type II source coincides with the interface between the CME EUV wave front and a nearby coronal ray structure, providing evidence that the type II emission is physically related to the CME-ray interaction. This result, consistent with those of previous studies, is based on simultaneous radio and EUV imaging data for the first time.

Chen, Yao; Du, Guohui

2014-06-01

223

Elemental composition before, during and after the January 6, 1997, CME event measured by CELIAS/SOHO  

NASA Technical Reports Server (NTRS)

Using solar wind particle data from the charge, element and isotope analysis system (CELIAS) experiment on the SOHO mission, densities of the elements O, Ne, Mg, Si, S, Ca, and Fe are derived, and their abundance is analyzed before, during and after the 6 Janaury 1997 coronal mass ejection event (CME). In the interstream and coronal hole regions before and after this event, typical solar wind abundances for the elements investigated were found. However, during the passage of the coronal mass ejection and during the passage of the erupted filament, the elemental composition differed markedly from typical solar wind. For the passage of the CME and for the passage of the erupted filament, a mass-dependent enhancement of the elements was found, with a monotonic increase towards heavier elements. Si/O and Fe/O ratios of the order of one during these time periods were observed.

Wurz, P.; Ipavich, F. M.; Galvin, A. B.; Bochsler, P.; Aellig, M. R.; Kallenbach, R.; Hovestadt, D.; Gruenwaldt, H.; Hilchenbach, M.; Axford, W. I.; Balsiger, H.; Buergi, A.; Coplan, M. A.; Geiss, J.; Gliem, F.; Gloeckler, G.; Hefti, S.; Hsieh, K. C.; Klecker, B.; Lee, M. A.

1997-01-01

224

Tracking the momentum flux of a CME and quantifying its influence on geomagnetically induced currents at Earth  

NASA Astrophysics Data System (ADS)

We investigate a CME propagating towards Earth on 29 March 2011. This event is specifically chosen for its predominately northward directed magnetic field, so that the influence from the momentum flux onto Earth can be isolated. We focus our study on understanding how a small Earth-directed segment propagates. Mass images are created from the white-light cameras onboard STEREO which are also converted into mass height-time maps (mass J-maps). The mass tracks on these J-maps correspond to the sheath region between the CME and its associated shock front as detected by in situ measurements at L1. A time-series of mass measurements from the STEREO COR-2A instrument are made along the Earth propagation direction. Qualitatively, this mass time-series shows a remarkable resemblance to the L1 in situ density series. The in situ measurements are used as inputs into a 3D magnetospheric space weather simulation from CCMC. These simulations display a sudden compression of the magnetosphere from the large momentum flux at the leading edge of the CME and predictions are made for the time-derivative of the magnetic field (dB/dt) on the ground. The predicted dB/dt were then compared with observations from specific equatorially-located ground stations and show notable similarity. This study of the momentum of a CME from the Sun down to its influence on magnetic ground stations on Earth is presented as preliminary proof of concept, such that future attempts may try to use remote sensing to create density and velocity time-series as inputs to magnetospheric simulations.

Savani, Neel; Vourlidas, Angelos; Pullkinen, Antti

2013-04-01

225

Tracking the momentum flux of a CME and quantifying its influence on geomagnetically induced currents at Earth  

NASA Astrophysics Data System (ADS)

We investigate a coronal mass ejection (CME) propagating toward Earth on 29 March 2011. This event is specifically chosen for its predominately northward directed magnetic field, so that the influence from the momentum flux onto Earth can be isolated. We focus our study on understanding how a small Earth-directed segment propagates. Mass images are created from the white-light cameras onboard STEREO which are also converted into mass height-time maps (mass J-maps). The mass tracks on these J-maps correspond to the sheath region between the CME and its associated shock front as detected by in situ measurements at L1. A time series of mass measurements from the STEREO COR-2A instrument is made along the Earth propagation direction. Qualitatively, this mass time series shows a remarkable resemblance to the L1 in situ density series. The in situ measurements are used as inputs into a three-dimensional (3-D) magnetospheric space weather simulation from the Community Coordinated Modeling Center. These simulations display a sudden compression of the magnetosphere from the large momentum flux at the leading edge of the CME, and predictions are made for the time derivative of the magnetic field (dB/dt) on the ground. The predicted dB/dt values were then compared with the observations from specific equatorially located ground stations and showed notable similarity. This study of the momentum of a CME from the Sun down to its influence on magnetic ground stations on Earth is presented as a preliminary proof of concept, such that future attempts may try to use remote sensing to create density and velocity time series as inputs to magnetospheric simulations.

Savani, N. P.; Vourlidas, A.; Pulkkinen, A.; Nieves-Chinchilla, T.; Lavraud, B.; Owens, M. J.

2013-05-01

226

Tracking the momentum flux of a CME and quantifying its influence on geomagnetically induced currents at Earth  

NASA Astrophysics Data System (ADS)

We investigate a CME propagating towards Earth on 29 March 2011. This event is specifically chosen for its predominately northward directed magnetic field, so that the influence from the momentum flux onto Earth can be isolated. We focus our study on understanding how a small Earth-directed segment propagates. Mass images are created from the white-light cameras onboard STEREO which are also converted into mass height-time maps (mass J-maps). The mass tracks on these J-maps correspond to the sheath region between the CME and its associated shock front as detected by in situ measurements at L1. A time-series of mass measurements from the STEREO COR-2A instrument are made along the Earth propagation direction. Qualitatively, this mass time-series shows a remarkable resemblance to the L1 in situ density series. The in situ measurements are used as inputs into a 3D magnetospheric space weather simulation from CCMC. These simulations display a sudden compression of the magnetosphere from the large momentum flux at the leading edge of the CME and predictions are made for the time-derivative of the magnetic field (dB/dt) on the ground. The predicted dB/dt were then compared with observations from specific equatorially-located ground stations and show notable similarity. This study of the momentum of a CME from the Sun down to its influence on magnetic ground stations on Earth is presented as preliminary proof of concept, such that future attempts may try to use remote sensing to create density and velocity time-series as inputs to magnetospheric simulations.

Savani, N. P.; Vourlidas, A.; Pulkkinen, A.; Nieves-Chinchilla, T.; Lavraud, B.; Owens, M. J.

2013-05-01

227

Three-dimensional propagation of coronal mass ejections in a structured solar wind flow 2. CME launched adjacent to the streamer belt  

Microsoft Academic Search

A three-dimensional (3-D) numerical hydrodynamic model is used to investigate the evolution of coronal mass ejections (CMEs) launched at several heliographic positions into a tilted-dipole ambient solar wind (SW) flow, which is appropriate around solar activity minimum and declining phase. The CME is injected as an overpressured plasma cloud. Results show that the motion and local appearance of a CME

D. Odstrcil; V. J. Pizzo

1999-01-01

228

Numerical experiments of magnetic reconnection in the solar flare and CME current sheet  

NASA Astrophysics Data System (ADS)

Magnetic reconnection plays a critical role in the energy conversion in the solar eruption. This paper performs a set of MHD experiments for the magnetic reconnection process in a current sheet formed in a disrupting magnetic configuration. The eruption results from the loss of equilibrium in the magnetic configuration that includes a current-carrying flux rope, which is used to model the filament floating in the corona. In order to study the fine structure and micro process inside the current sheet (CS), the mesh refinement technology is used to depress the numerical diffusion. A uniform physical diffusion is applied and results in a Lundquist number S=10^4 in the vicinity of CS. Because of the advantage of the foregoing setting, some features appear with high resolution, including plasmoids due to the tearing mode and the plasmoid instabilities, turbulence regions, and the slow mode shocks. Inside CS, magnetic reconnection goes through the Sweet-Parker and the fractal fashions, and eventually, it displays a time-dependent Petschek pattern. Our results seem to support the concept of fractal reconnection suggested by Shibata et al. (1995) and Shibata & Tanuma (2001). And our results suggest that the CS evolves through a Sweet-Parker reconnection prior to the fast reconnection stage. For the first time, the detailed features and/or fine structures inside the CME/flare CS in the eruption were investigated in this work.

Mei, Zhixing; Lin, Jun; Shen, Chengcai

2012-07-01

229

Post Alpbach-summerschool project: CARRINGTON MISSION FOR CME DETECTION TO IMPROVE SPACE WEATHER FORECAST  

NASA Astrophysics Data System (ADS)

The effects of solar activity, especially Coronal Mass Ejections (CMEs), on Earth- and satellite-based systems are well-known and can cause major damage to space-dependent infrastructure. The main problem in current space weather forecasting is the inability to determine necessary forecast parameters of CMEs and Corotating Interaction Regions (CIRs) early enough to react. We present the design for a novel space mission consisting of two spacecraft that is aimed to perform stereoscopic measurements on Earth-directed CMEs and in-situ measurements of CIRs. The magnetic field orientation and structure of CMEs will be measured close to the Sun, using spectro-polarimetry. Geoeffectiveness will be derived by remote sensing the CMEs magnetic field at 0.64AU from the Sun, determining the full magnetic field vector of a CME. This will be achieved by the novel concept of measuring its polarising effects on spacecraft to spacecraft laser beams based upon heterodyne interferometry. Overall structure and trajectory of CMEs will also be monitored by heliospheric imagers and in-situ plasma instruments. To achieve the mission objectives, the orbit is heliocentric at 1AU with a separation angle from the Earth of ±50°. The operational mission lifetime is 6 years with a proposed 6 year extension. If implemented, Carrington will serve as a forecast system which will significantly improve the minimum forecast time for the fastest CMEs with 2000 km/s, from 13 minutes based on current L1 satellites, to around 3 hours.

Scheucher, Markus; Urbar, Jaroslav; Musset, Sophie; Andersson, Viktor; Gini, Francesco; Gorski, Jedrzej; Jüstel, Peter; Kiefer, René; Lee, Arrow; Meskers, Arjan; Miles, Oscar; Perakis, Nikolas; Rußwurm, Michael; Scully, Stephen; Seifert, Bernhard; Sorba, Arianna

2014-05-01

230

CME-driven Shock Simulations and Observations: Variability of SEP Abundances, Mechanisms, and Validation  

NASA Astrophysics Data System (ADS)

In the past decade, much progress has been made by way of satellite observations regarding the origin and acceleration mechanisms of solar energetic particles (SEPs). In comparison, relatively little work has been done on the side of event-based simulations. In particular in the context of developing quantitative models of SEP fluxes and spectra, it is of great concern to understand their intrinsic possible variability, and to address the question whether the prevalence and efficiency of different contributing mechanisms can be estimated or predicted. Using ACE data, we have selected a number of characteristic "energetic storm particle" (ESP) events, i.e., SEP events in which the CME-driven shock passes the spacecraft, to compare observed local proton flux profiles with those obtained from large-scale hybrid simulations (kinetic ions, electron fluid). The events were selected for relatively undisturbed solar wind, isolation from other events, and flux profiles that clearly indicate local shock acceleration. Interestingly, in the sub-MeV range, we find very little variation of peak proton fluxes with shock normal angle. In our simulations we have investigated the role of seed particles, the acceleration processes at oblique shocks, and other effective mechanisms such as mirroring of energetic ions in downstream converging fields. In addition, shock curvature on various scales can play a role. Via direct comparison with the observed events, we discuss the pertinent acceleration mechanisms and the feasibility of predicting their respective, relative importance and occurrence.

Krauss-Varban, D.; Li, Y.; Luhmann, J. G.

2007-12-01

231

Solar Energetic Particle Events: Flares and CME-Driven Shock Waves  

NASA Astrophysics Data System (ADS)

During the past 15 years, a new paradigm has been developed for solar energetic particle (SEP) events in which the particles observed in space following solar activity are thought to be accelerated either in flares (small impulsive SEP events with high-Z abundance anomalies and high Fe charge states) or at CME-driven coronal/interplanetary shock waves (large gradual events with "normal" abundances and low Fe charge states). Observations from the Advanced Composition Explorer (ACE), however, have shown that at energies > 10 MeV/amu, certain large gradual events have event-averaged abundances and charge states that look remarkably impulsive (e.g., Cohen et al., GRL 26, 2697, 1999). Recently-analyzed large events observed by the IMP-8 spacecraft since 1973 exhibit similar behavior (Dietrich and Lopate, Proc. 27th ICRC, 8, 3120, 2001). I review the various suggestions that have been made to account for these "mixed" events in terms of propagation effects and/or seed particle populations.

Cliver, E. W.

2001-12-01

232

CME Mass Estimates via EVE Coronal Dimmings for X-class Flares  

NASA Astrophysics Data System (ADS)

The EVE instrument on SDO detects post-flare dimmings, mainly in the spectral regions of Fe IX-XII in its MEGS-A range, which is available for most of the 29 X-class flares that have occurred between SDO launch and the end of April 2014. Based upon earlier X-ray observations we interpret these dimmings as the result of CME mass ejection from the low corona. We estimate the masses involved in these dimmings by deriving a best pre-event temperature and emission measure in the dimmed region from EVE, and a source volume from AIA images. The dimming for SOL2011-02-15, the first of these events, "peaked"at -3.4% in Fe IX in terms of the pre-event emission from the whole Sun, with smaller relative depletions in higher ionization states of Fe. The "maximum" occurred more than one hour after GOES peak. The dimming signature is generally cleanly measurable in the EVE/MEGS-A spectral samples at10 s cadence, with the dominant source of uncertainty stemming from the "sun-as-a-star" integrations; for example flare-related excess emission at a given wavelength tends to compensate for the dimming,and in this sense the mass estimate must be considered a lower limit. We address these uncertainties for the solar case by appealing to the AIA images, but for analogous processes in stellar flares one would not have this luxury.

Hudson, Hugh S.; Hannah, Iain; Schrijver, Karel

2014-06-01

233

The storm-time plasma sheet at geosynchronous orbit : CME- and CIR-dominated solar wind  

NASA Astrophysics Data System (ADS)

The plasma sheet provides the primary source population for the storm-time ring current, and characteristic storm signatures are produced by the plasma sheet penetrating deep into the inner magnetosphere. Geosynchronous orbit offers an excellent vantage point from which to monitor the plasma sheet population that ultimately becomes the storm-time ring current. For well over a complete solar cycle, Los Alamos has been fielding magnetospheric plasma analyzers at geosynchronous orbit, creating an extensive multi-point database of plasma sheet conditions. Previous statistical analyses of these data have revealed important information about the access that the plasma sheet has to the inner magnetosphere. More recently, we have performed superposed epoch studies of the variation of plasma sheet properties as a function of storm phase. In the current study, we examine the storm-time behaviour for storms sorted according to the likely solar wind driver, i.e., CME-driven and CIR high-speed-stream-driven, and according to the phase of the solar cycle. We compare the geosynchronous data with data from the MENA instrument on-board the IMAGE satellite to investigate the global distribution of energetic ions in the inner magnetosphere during such events.

Denton, M. H.; Thomsen, M. F.; Skoug, R. M.; Borovsky, J. E.; Henderson, M. G.; McPherron, R. L.; Pollock, C.

2005-05-01

234

Why S, Not X, Marks the Spot for CME/Flare Eruptions  

NASA Technical Reports Server (NTRS)

For any major CME/flare eruption: I. The field that erupts is an arcade in which the interior is greatly sheared and twisted. Most of the free magnetic energy to be released: a) Is in the shear and twist of the interior field. b) Is Not due to a big current sheet. The eruption is unleashed by reconnection at a growing current sheet. The current sheet is still little when the reconnection turns on. The unleashed eruption then makes the current sheet much bigger by building it up faster than the reconnection can tear it down. II. Most X-ray jets work the opposite way: a) Tapped free energy is in the field of a pre-jet current sheet. b) Current sheet built by small arcade emerging into ambient field. c) Current sheet still much smaller than the arcade when reconnection turns on and tears it down, producing a jet. III. These rules reflect the low-beta condition in the eruptive magnetic field

Moore, Ronald L.; Sterling, Alphonse; Gary, Allen; Cirtain, Jonathan; Falconer, David

2010-01-01

235

The Solar Corona and a CME at the 2010 Total Eclipse  

NASA Astrophysics Data System (ADS)

The 11 July 2010 total solar eclipse was observed on the ground from French Polynesia and, 83 minutes later, from Easter Island, and near-simultaneous images were made with spacecraft instruments including AIA/SDO, HMI/SDO, EUVI/STEREO, SWAP/PROBA2, EIT/SOHO, and LASCO/SOHO. We report on changes in the corona detectable with high-resolution image processing of the ground-based eclipse coronal imaging, including two CME's that were seen to evolve. We compare with the spacecraft images to give a complete depiction of coronal structure at the time of the eclipse, which corresponded to a low but rising phase of the solar-activity cycle. We acknowledge the support of NASA's MSFC NNX10AK47A, NSF REU AST-1005024 with DoD ASSURE, VEGA 2/0098/10 of the Slovak Acad. Sci, 205/09/1469 of the Czech Science Foundation, PRODEX C90345 of ESA/BELSPO, FP7/2007-2013/218816 SOTERIA, Lockheed Martin; for equipment: Nikon Professional Services, ASTELCO Systems GmbH (Germany), and National Geographic Society's Photographic Division; and colleagues Y.-M. Wang (NRL), S. Habbal (U. Hawaii), H. Lanteires (Tatakoto), and J. Kern (Carnegie Obs.).

Pasachoff, Jay M.; Rusin, V.; Druckmüllerová, H.; Saniga, M.; Lu, M.; Malamut, C.; Seaton, D. B.; Golub, L.; Engell, A. J.; Hill, S. W.; Lucas, R.

2011-05-01

236

Kinetic Approaches to Shear-Driven Magnetic Reconnection for Multi-Scale Modeling of CME Initiation  

NASA Astrophysics Data System (ADS)

In the standard model for coronal mass ejections (CME) and/or solar flares, the free energy for the event resides in the strongly sheared magnetic field of a filament channel. The pre-eruption force balance, consisting of an upward force due to the magnetic pressure of the sheared field balanced by a downward tension due to overlying un-sheared field, is widely believed to be disrupted by magnetic reconnection. Therefore, understanding initiation of solar explosive phenomena requires a true multi-scale model of reconnection onset driven by the buildup of magnetic shear. While the application of magnetic-field shear is a trivial matter in MHD simulations, it is a significant challenge in a PIC code. The driver must be implemented in a self-consistent manner and with boundary conditions that avoid the generation of waves that destroy the applied shear. In this work, we describe drivers for 2.5D, aperiodic, PIC systems and discuss the implementation of driver-consistent boundary conditions that allow a net electric current to flow through the walls. Preliminary tests of these boundaries with a MHD equilibrium are shown. This work was supported, in part, by the NASA Living With a Star TR&T Program.

Black, C.; Antiochos, S. K.; DeVore, C.; Germaschewski, K.; Karpen, J. T.

2013-12-01

237

SMEI 3D RECONSTRUCTION OF A CORONAL MASS EJECTION INTERACTING WITH A COROTATING SOLAR WIND DENSITY ENHANCEMENT: THE 2008 APRIL 26 CME  

SciTech Connect

The Solar Mass Ejection Imager (SMEI) has recorded the brightness responses of hundreds of interplanetary coronal mass ejections (CMEs) in the interplanetary medium. Using a three-dimensional (3D) reconstruction technique that derives its perspective views from outward-flowing solar wind, analysis of SMEI data has revealed the shapes, extents, and masses of CMEs. Here, for the first time, and using SMEI data, we report on the 3D reconstruction of a CME that intersects a corotating region marked by a curved density enhancement in the ecliptic. Both the CME and the corotating region are reconstructed and demonstrate that the CME disrupts the otherwise regular density pattern of the corotating material. Most of the dense CME material passes north of the ecliptic and east of the Sun-Earth line: thus, in situ measurements in the ecliptic near Earth and at the Solar-TErrestrial RElations Observatory Behind spacecraft show the CME as a minor density increase in the solar wind. The mass of the dense portion of the CME is consistent with that measured by the Large Angle Spectrometric Coronagraph on board the Solar and Heliospheric Observatory spacecraft, and is comparable to the masses of many other three-dimensionally reconstructed solar wind features at 1 AU observed in SMEI 3D reconstructions.

Jackson, B. V.; Buffington, A.; Hick, P. P.; Clover, J. M.; Bisi, M. M. [Center for Astrophysics and Space Sciences, University of California at San Diego, 9500 Gilman Drive, 0424, La Jolla, CA 92093-0424 (United States); Webb, D. F. [Institute for Space Research, Boston College, Chestnut Hill, MA, 02467 (United States)

2010-12-01

238

Does an offer for a free on-line continuing medical education (CME) activity increase physician survey response rate? A randomized trial  

PubMed Central

Background Achieving a high response rate in a physician survey is challenging. Monetary incentives increase response rates but obviously add cost to a survey project. We wondered whether an offer of a free continuing medical education (CME) activity would be effective in improving survey response rate. Results As part of a survey of a national sample of physicians, we randomized half to an offer for a free on-line CME activity upon completion of a web-based survey and the other half to no such offer. We compared response rates between the groups. A total of 1214 out of 8477 potentially eligible physicians responded to our survey, for an overall response rate of 14.3%. The response rate among the control group (no offer of CME credit) was 16.6%, while among those offered the CME opportunity, the response rate was 12.0% (p < 0.0001). Conclusions An offer for a free on-line CME activity did not improve physician survey response rate. On the contrary, the offer for a free CME activity actually appeared to worsen the response rate.

2012-01-01

239

Low Temperature Hysteretic Behavior of the Interpenetrating 3-D Network Structured [Ru2(O2CMe)4]3[Fe(CN)6] Magnet  

SciTech Connect

The low temperature hysteretic behavior between 40 mK and 4.8 K was obtained for [Ru2(O2CMe)4]3[Fe(CN)6]. The unusual constricted hysteretic behavior reported for isomorphous [Ru2(O2CMe)4]3[Cr(CN)6] was not observed. Instead, the [Ru2(O2CMe)4]3-[Fe(CN)6] exhibits a single hysteresis loop and a temperature dependence of the coercivity atypical for a ferrimagnetic ordering transition. The coercive field, constant below ~0.3 K (1.06 kOe), shows a rapid initial decrease below 1 K, to continue decreasing at a slower rate up to at least 4.8 K. In contrast to [Ru2(O2CMe)4]3[Cr(CN)6] which has antiferromagnetic coupling of the ferrimagnetic lattices, due to the reduced spin on the [FeIII(CN)6]3-, [Ru2(O2CMe)4]3[Fe(CN)6] ferromagnetic coupling of the ferrimagnetic lattices dominates for [Ru2(O2CMe)4]3[Fe(CN)6].

Haque, F. [University of Central Florida; Del barco, Enrique [University of Central Florida; Fishman, Randy Scott [ORNL; Miller, Joel S. [University of Utah

2013-01-01

240

COLON TARGETED DRUG DELIVERY SYSTEMS  

Microsoft Academic Search

Colon targeted drug delivery systems have the potential to deliver drugs for the treatment of a variety of colonic diseases and to deliver proteins and peptides to the colon for their systemic absorption. In recent years, various pharmaceutical approaches have been developed for targeting the drugs to the colon include, formation of prodrugs, coating of pH-sensitive polymers, use of colon

Ceyda Tuba

241

Dioxygen activation by an organometallic Pd(II) precursor: formation of a Pd(IV)-OH complex and its C-O bond formation reactivity.  

PubMed

The complex (Me3tacn)Pd(II)(CH2CMe2C6H4) is readily oxidized by O2 or H2O2 to yield the Pd(IV)-OH complex [(Me3tacn)Pd(IV)(OH)(CH2CMe2C6H4)](+). Thermolysis of this product leads to the selective C(sp(2))-O reductive elimination of 2-tert-butylphenol, no C(sp(3))-O elimination product being detected. This system represents a rare example of selective C(sp(2))-O bond formation that is relevant to Pd-catalyzed aerobic C-H hydroxylation reactions. PMID:24509780

Qu, Fengrui; Khusnutdinova, Julia R; Rath, Nigam P; Mirica, Liviu M

2014-03-21

242

Use of Yohkoh SXT in Measuring the Net Current and CME Productivity of Active Regions  

NASA Astrophysics Data System (ADS)

In our investigation of the correlation of global nonpotentiality of active regions to their CME productivity (Falconer, D. A. 2001, JGR, in press, and Falconer, Moore, & Gary, 2000, EOS 82, 20 S323), we use Yohkoh SXT images for two purposes. The first use is to help resolve the 180o ambiguity in the direction of the observed transverse magnetic field. Resolution of the 180o ambiguity is important, since the net current, one of our measures of global nonpotentiality, is derived from integrating the dot product of the transverse field around a contour (IN = int BTcdot dl). The ambiguity results from the observed transverse field being determined from the linear polarization, which gives the plane of the direction, but leaves a 180o ambiguity. Automated methods to resolve the ambiguity ranging from the simple acute angle rule (Falconer, D. A. 2001) to the more sophisticated annealing method (Metcalf T. R. 1994). For many active regions, especially ones that are nearly potential these methods work well. But for very nonpotential active regions where the shear angle (the angle between the observed and potential transverse field) is near 90o throughout large swaths along the main neutral line, both methods can resolve the ambiguity incorrectly for long segments of the neutral line. By determining from coronal images, such as those from Yohkoh/SXT, the sense of shear along the main neutral line in the active region, these cases can be identified and corrected by a modification of the acute angle rule described here. The second use of Yohkoh/SXT in this study is to check for the cusped coronal arcades of long-duration eruptive flares. This signature is an excellent proxy for CMEs, and was used by Canfield, Hudson, and McKenzie (1999 GRL V26, 6, 627-630). This work is funded by NSF through the Space Weather Program and by NASA through the Solar Physics Supporting Research and Technology Program.

Falconer, D. A.; Moore, R. L.; Gary, G. A.

2002-01-01

243

May 12 1997 CME Event: A Simplified Model of the Pre-Eruptive Magnetic Structure  

NASA Astrophysics Data System (ADS)

A simple model of the coronal magnetic field prior to the CME eruption on May 12 1997 is developed. First, this field is constructed by superimposing a large-scale background field and a localized bipolar field to model the active region (AR) in the potential approximation. The background field is determined from the observed photospheric normal field averaged over the longitude of the Sun. The AR field is modeled by a subphotospheric dipole whose parameters are optimized to fit the magnetic field obtained from an MDI magnetogram. Second, this potential configuration is quasi-statically sheared by photospheric vortex motions applied to two flux concentrations of the AR. Third, the resulting force-free field is then evolved by canceling the photospheric flux with the help of a flow converging to the neutral line of the AR. To understand the structure of the modeled configuration, we use a field line mapping technique generalized to spherical geometry. It is demonstrated that the initial configuration contains a hyperbolic flux tube (HFT) consisting of two intersecting quasi-separatrix layers. This HFT provides a partition of the closed magnetic flux between the AR and global solar magnetic field. Such a partition is approximate since the entire flux distribution is perfectly continuous. The vortex motions applied to the AR interlock the coronal field lines to form additionally two new HFTs pinched into thin current layers (CLs). These CLs carry the return current shielding the twisted field of the AR from a nearly potential background field. Reconnection in these CLs helps redistribute the flux in the configuration during the cancellation phase. At this phase, a magnetic flux rope is formed together with a bald patch separatrix surface wrapping around the rope. Other important implications of the identified structural features of the modeled configuration are also discussed.

Titov, Viacheslav; Mikic, Z.; Linker, J. A.; Lionello, R.

2007-05-01

244

A Multi-Viewpoint Validation of CME Propagation Through a New MHD Turbulence Solar Wind Model  

NASA Astrophysics Data System (ADS)

On March 2011 March 7, a fast CME (> 2000 km/s) erupted in NOAA 11164. We present a multi-spacecraft validation study of a numerical simulation for this event as well as for the related ambient solar wind Carrington rotation 2107 using a new Alfven-wave turbulence solar wind model. We compare the simulated multi-wavelength EUV images with the SDO/AIA observations, differential emission measure tomography and in-situ measurements at 1 AU. The results are compared to remote as well as in-situ observation from SOHO, STEREOA/B, ACE, and WIND. Our result shows that the new model can reproduce most of the observed features near the Sun and in the heliosphere. Our new global solar wind model is developed within the Space Weather Modeling Framework (SWMF) and accounts for the different electron and ion temperatures. This model can simulate from the upper chromosphere up to 1AU. The realistic 3D magnetic field is simulated using the data from the photospheric magnetic field measurements. The solar wind is driven by the outward propagating Poynting flux emerging from the lower chromosphere that is carried by low frequency MHD waves. This turbulence and its non-linear dissipation is the only momentum and energy source for heating the coronal plasma and driving the solar wind. The model includes wave-energy injection, transmission, reflection due to large-scale plasma inhomogeneities and dissipation. The wave reflection leads to low-frequency cascade of Alfven waves due to small-scale nonlinearities. In closed field line regions, the dissipation is enhanced since different wave polarities can interact with equal amplitude, resulting in elevated temperatures. The electron heat conduction can subsequently transport this excess of energy deposition down to the chromosphere where it is lost by radiative cooling. The model does not impose open-closed magnetic field boundaries, those naturally develop from the photospheric magnetic fields.

van der Holst, Bart; Jin, Meng; Sokolov, Igor; Manchester, Ward B.; Oran, Rona; Gombosi, Tamas I.

2013-04-01

245

CME-Producing Precursors to the 2006 December 13 X-Flare  

NASA Technical Reports Server (NTRS)

We revisit one of the largest explosions observed during the Hinode era, the X4.3 class event of 2006 Dec 13. We gain insight into the main eruption through study of two sub-C-class precursor eruptions, occurring within 12 hours of and originating from the same (or nearby) neutral line as the X-flare. The precursors share some features in common with the main eruption, and their lower energy and consequent slower development renders interpretation of these features easier to decipher than in the rapidly explosive main eruption. In addition, because the weak precursors occurred in a magnetically strong region, magnetic connections indicated by soft X-ray loops are readily visible in these cases, while such connections can be much less apparent in weaker-region eruptions. Hinode/SOT magnetograms indicate that photospheric magnetic dynamic activity in the "magnetic core" is the likely ultimate source of the eruptions. All the eruptions, however, produce Coronal Mass Ejections (CMEs) that have wider spatial extent than the localized source region; this is a long-observed but puzzling phenomena, which can address directly here using the high-quality Hinode data. For the precursor eruptions, Hinode/XRT images show that the initial eruptions occur inside larger-scale magnetic structures that encompass the core. The exploding core field blows out this larger-scale structure, resulting in the CME having angular extent far exceeding that of the source-region core alone; this is the arch-arch-blowout scenario for CMEs of Moore & Sterling (2007). Similar processes occur in the main eruption, except that the much larger energy release in that eruption compared to the precursors results in much faster and larger-scale phenomena.

Sterling, Alphonse C.; Harra, Louise K.; Moore, Ronald L.

2008-01-01

246

Cationic liposomes for gene delivery.  

PubMed

Cationic liposome-DNA complexes (lipoplexes) constitute a potentially viable alternative to viral vectors for the delivery of therapeutic genes. This review will focus on various parameters governing lipoplex biological activity, from their mode of formation to in vivo behaviour. Particular emphasis is given to the mechanism of interaction of lipoplexes with cells, in an attempt to dissect the different barriers that need to be surpassed for efficient gene expression to occur. Aspects related to new trends in the formulation of lipid-based gene delivery systems aiming at overcoming some of their limitations will be covered. Finally, examples illustrating the potential of cationic liposomes in clinical applications will be provided. PMID:16296751

Simões, Sérgio; Filipe, Ana; Faneca, Henrique; Mano, Miguel; Penacho, Nuno; Düzgünes, Nejat; de Lima, Maria Pedroso

2005-03-01

247

The effect of the delivery of vascular endothelial growth factor and bone morphogenic protein-2 to osteoprogenitor cell populations on bone formation.  

PubMed

Regenerating bone tissue involves complex, temporal and coordinated signal cascades of which bone morphogenic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF(165)) play a prominent role. The aim of this study was to determine if the delivery of human bone marrow stromal cells (HBMSC) seeded onto VEGF(165)/BMP-2 releasing composite scaffolds could enhance the bone regenerative capability in a critical sized femur defect. Alginate-VEGF(165)/P(DL)LA-BMP-2 scaffolds were fabricated using a supercritical CO(2) mixing technique and an alginate entrapment protocol. Increased release of VEGF(165) (750.4+/-596.8 rho g/ml) compared to BMP-2 (136.9+/-123.4 r hog/ml) was observed after 7-days in culture. Thereafter, up till 28 days, an increased rate of release of BMP-2 compared to VEGF(165) was observed. The alginate-VEGF(165)/P(DL)LA-BMP-2+HBMSC group showed a significant increase in the quantity of regenerated bone compared to the alginate-VEGF(165)/P(DL)LA-BMP-2 and alginate/P(DL)LA groups respectively in a critical sized femur defect study as indices measured by microCT. Histological examination confirmed significant new endochondral bone matrix in the HBMSC seeded alginate-VEGF(165)/P(DL)LA-BMP-2 defect group in comparison to the other groups. These studies demonstrate the ability to deliver a combination of HBMSC with angiogenic and osteogenic factors released from biodegradable scaffold composites enhances the repair and regeneration of critical sized bone defects. PMID:19926128

Kanczler, Janos M; Ginty, Patrick J; White, Lisa; Clarke, Nicholas M P; Howdle, Steven M; Shakesheff, Kevin M; Oreffo, Richard O C

2010-02-01

248

Polytetrahydrofuran- and dendrimer- based novel sol-gel coatings for capillary microextraction (cme) providing parts per trillion (ppt) and parts per quadrillion (ppq) level detection limits in conjunction with gas chromatography and flame ionization detection (fid)  

Microsoft Academic Search

Sol-gel capillary microextraction (CME) is a new direction in solvent-free extraction and preconcentration of trace analytes. CME presents significant interest in environmental, pharmaceutical, petrochemical, biomedical, agricultural, food, flavor, and a host of other important areas. Sol-gel CME utilizes advanced material properties of organic-inorganic hybrid sol-gel polymers to perform efficient extraction and enrichment of target analytes from a variety of matrices.

Abuzar Kabir

2005-01-01

249

Coronal mass ejection (CME) activity of low mass M stars as an important factor for the habitability of terrestrial exoplanets. I. CME impact on expected magnetospheres of Earth-like exoplanets in close-in habitable zones.  

PubMed

Low mass M- and K-type stars are much more numerous in the solar neighborhood than solar-like G-type stars. Therefore, some of them may appear as interesting candidates for the target star lists of terrestrial exoplanet (i.e., planets with mass, radius, and internal parameters identical to Earth) search programs like Darwin (ESA) or the Terrestrial Planet Finder Coronagraph/Inferometer (NASA). The higher level of stellar activity of low mass M stars, as compared to solar-like G stars, as well as the closer orbital distances of their habitable zones (HZs), means that terrestrial-type exoplanets within HZs of these stars are more influenced by stellar activity than one would expect for a planet in an HZ of a solar-like star. Here we examine the influences of stellar coronal mass ejection (CME) activity on planetary environments and the role CMEs may play in the definition of habitability criterion for the terrestrial type exoplanets near M stars. We pay attention to the fact that exoplanets within HZs that are in close proximity to low mass M stars may become tidally locked, which, in turn, can result in relatively weak intrinsic planetary magnetic moments. Taking into account existing observational data and models that involve the Sun and related hypothetical parameters of extrasolar CMEs (density, velocity, size, and occurrence rate), we show that Earth-like exoplanets within close-in HZs should experience a continuous CME exposure over long periods of time. This fact, together with small magnetic moments of tidally locked exoplanets, may result in little or no magnetospheric protection of planetary atmospheres from a dense flow of CME plasma. Magnetospheric standoff distances of weakly magnetized Earth-like exoplanets at orbital distances

Khodachenko, Maxim L; Ribas, Ignasi; Lammer, Helmut; Griessmeier, Jean-Mathias; Leitner, Martin; Selsis, Franck; Eiroa, Carlos; Hanslmeier, Arnold; Biernat, Helfried K; Farrugia, Charles J; Rucker, Helmut O

2007-02-01

250

Transforming in-situ observations of CME-driven shock accelerated protons into the shock's reference frame.  

NASA Astrophysics Data System (ADS)

We examine the solar energetic particle event following solar activity from 14, 15 April 2001 which includes a "bump-on-the-tail" in the proton energy spectra at 0.99 AU from the Sun. We find this population was generated by a CME-driven shock which arrived at 0.99 AU around midnight 18 April. As such this population represents an excellent opportunity to study in isolation, the effects of proton acceleration by the shock. The peak energy of the bump-on-the-tail evolves to progressively lower energies as the shock approaches the observing spacecraft at the inner Lagrange point. Focusing on the evolution of this peak energy we demonstrate a technique which transforms these in-situ spectral observations into a frame of reference co-moving with the shock whilst making allowance for the effects of pitch angle scattering and focusing. The results of this transform suggest the bump-on-the-tail population was not driven by the 15 April activity but was generated or at least modulated by a CME-driven shock which left the Sun on 14 April. The existence of a bump-on-the-tail population is predicted by models in Rice et al. (2003) and Li et al. (2003) which we compare with observations and the results of our analysis in the context of both the 14 April and 15 April CMEs. We find an origin of the bump-on-the-tail at the 14 April CME-driven shock provides better agreement with these modelled predictions although some discrepancy exists as to the shock's ability to accelerate 100 MeV protons. Keywords. Solar physics, astrophysics and astronomy (Energetic particles; Flares and mass ejections) Space plasma physics (Transport processes)

Robinson, I. M.; Simnett, G. M.

2005-07-01

251

Comparison of the CME-associated shock arrival times at the earth using the WSA-ENLIL model with three cone models  

NASA Astrophysics Data System (ADS)

We have made a comparison of CME-associated shock arrival times at the earth based on the WSA-ENLIL model with three cone models using 29 halo CMEs from 2001 to 2002. These halo CMEs have cone model parameters from Michalek et al. (2007) as well as their associated interplanetary (IP) shocks. For this study we consider three different cone models (an asymmetric cone model, an ice-cream cone model and an elliptical cone model) to determine CME cone parameters (radial velocity, angular width and source location), which are used for input parameters of the WSA-ENLIL model. The mean absolute error (MAE) of the arrival times for the elliptical cone model is 10 hours, which is about 2 hours smaller than those of the other models. However, this value is still larger than that (8.7 hours) of an empirical model by Kim et al. (2007). We are investigating several possibilities on relatively large errors of the WSA-ENLIL cone model, which may be caused by CME-CME interaction, background solar wind speed, and/or CME density enhancement.

Jang, S.; Moon, Y.; Na, H.

2012-12-01

252

DNA amplification via polymerase chain reaction inside miniemulsion droplets with subsequent poly(n-butylcyanoacrylate) shell formation and delivery of polymeric capsules into mammalian cells.  

PubMed

There is a growing interest in the development of stable nanocapsules that could deliver the bioactive compounds within the living organism, and to release them without causing any toxic effects. Here the miniemulsion droplets were first used as "nanoreactors" for the amplification of single-molecule dsDNA template (476 and 790 base pairs) through PCR. Afterwards, each droplet was surrounded with a biodegradable PBCA shell by interfacial anionic polymerization, enabling therefore to deliver the PCR products into the cells. The size of the initial miniemulsion droplets and the final polymeric capsules was in the range of 250 and 320 nm, mainly depending on the type of the continuous phase and presence of dsDNA template molecules. The formation of PCR products was resolved with gel electrophoresis and detected with fluorescence spectroscopy in the presence of DNA specific dye (SYBRGreen). TEM studies were performed to prove the formation of the polymeric shell. The shell thickness was measured to be within 5-15 nm and the average molecular weight of the formed PBCA polymer was around 75000 g · mol(-1) . For the cell uptake experiments, the obtained nanocapsules were transferred from the organic phase into aqueous medium containing a water-soluble surfactant. The effect of the surfactant type (anionic, cationic or non-ionic) on the HeLa cell viability and nanocapsule uptake behavior was studied by CLSM and FACS. Confocal analysis demonstrated that nanocapsules stabilized with cationic (CTMA-Cl) and non-ionic (Lutensol AT50) surfactants show almost the same uptake, whereas capsules redispersed in anionic (SDS) surfactant possess a 30% higher uptake. The release of the encapsulated material within the cell was studied on the example of Cy5-labeled oligonucleotides showing the colocalization with mitochondria of MSCs cells. PMID:21557476

Baier, Grit; Musyanovych, Anna; Landfester, Katharina; Best, Andreas; Lorenz, Steffen; Mailänder, Volker

2011-08-11

253

43 CFR Appendix II to Part 11 - Format for Data Inputs and Modifications to the NRDAM/CME  

Code of Federal Regulations, 2013 CFR

...time of flood stage (i.e., rising tide) consisting ofâ An east-west (U...MD (310) 436-6990; and the Eldridge Tide and Pilot Book, Robert Eldridge White...Boston, MA (617) 742-3045.] Tides Hour of high tide on the day that...

2013-10-01

254

43 CFR Appendix II to Part 11 - Format for Data Inputs and Modifications to the NRDAM/CME  

Code of Federal Regulations, 2010 CFR

...in meters; and Whether the tide in the area affected by the...river flow, water density, and tides, that remains when all the...gravitational forces between the earth, moon, and sun. Tidal range...highest and lowest height of the tide. [61 FR 20612, May...

2009-10-01

255

43 CFR Appendix II to Part 11 - Format for Data Inputs and Modifications to the NRDAM/CME  

Code of Federal Regulations, 2010 CFR

...in meters; and Whether the tide in the area affected by the...river flow, water density, and tides, that remains when all the...gravitational forces between the earth, moon, and sun. Tidal range...highest and lowest height of the tide. [61 FR 20612, May...

2010-10-01

256

Decametric radio bursts associated with the 13 July 2004 CME event at frequencies 10-30 MHz  

NASA Astrophysics Data System (ADS)

We report on the observations of solar type IV burst and its precursors on the 13 of July 2004 at frequencies 10-30 MHz. The radio telescope UTR-2 observational data compiled from SOHO, WIND, NDA, RHESSI, GOES data were used. The main properties (frequency drift rate, duration, flux) of type IV burst and its precursors, namely solar type III and type II bursts, are analysed. We consider the type IV burst connected with appearance of the coronal mass ejection, which occurrence coincides with the type IV burst beginning. Several physical characteristics of this CME were estimated.

Boiko, A. I.; Melnik, V. N.; Konovalenko, A. A.; Abranin, E. P.; Dorovskyy, V. V.; Rucker, H. O.

2012-03-01

257

Real-Time CME Forecasting Using HMI Active-Region Magnetograms and Flare History  

NASA Technical Reports Server (NTRS)

We have recently developed a method of predicting an active region s probability of producing a CME, an X-class Flare, an M-class Flare, or a Solar Energetic Particle Event from a free-energy proxy measured from SOHO/MDI line-of-sight magnetograms. This year we have added three major improvements to our forecast tool: 1) Transition from MDI magnetogram to SDO/HMI magnetogram allowing us near-real-time forecasts, 2) Automation of acquisition and measurement of HMI magnetograms giving us near-real-time forecasts (no older than 2 hours), and 3) Determination of how to improve forecast by using the active region s previous flare history in combination with its free-energy proxy. HMI was turned on in May 2010 and MDI was turned off in April 2011. Using the overlap period, we have calibrated HMI to yield what MDI would measure. This is important since the value of the free-energy proxy used for our forecast is resolution dependent, and the forecasts are made from results of a 1996-2004 database of MDI observations. With near-real-time magnetograms from HMI, near-real-time forecasts are now possible. We have augmented the code so that it continually acquires and measures new magnetograms as they become available online, and updates the whole-sun forecast from the coming day. The next planned improvement is to use an active region s previous flare history, in conjunction with its free-energy proxy, to forecast the active region s event rate. It has long been known that active regions that have produced flares in the past are likely to produce flares in the future, and that active regions that are nonpotential (have large free-energy) are more likely to produce flares in the future. This year we have determined that persistence of flaring is not just a reflection of an active region s free energy. In other words, after controlling for free energy, we have found that active regions that have flared recently are more likely to flare in the future.

Falconer, David; Moore, Ron; Barghouty, Abdulnasser F.; Khazanov, Igor

2011-01-01

258

Using SOHO to Understand CME-Producing Quiet-Region Filament Eruptions  

NASA Technical Reports Server (NTRS)

In recent years we have been studying solar eruptions in an attempt to determine their primary initiation mechanism. We have focused on events involving filaments, because motions of the filaments just prior to their violent eruption are indicative of changes in the entire magnetic field system involved in the eruption. When the pre-eruption filament resides in a quiet region, the motions leading up to eruption are slower than in similar eruptions in active regions due to the weaker magnetic field strength and correspondingly lower Alfven velocities. These early motions manifest themselves in a slow rise (a few km/s) of the filament, in some cases lasting several hours. After this the filament and associated magnetic structures erupt rapidly, accelerating to speeds of a few 10 kmh over a few minutes. Because of their slow evolution, quiet-region eruptions such as these can be effectively studied in EUV with SOHO/EIT, with its regular cadence of about 12 min. For several cases we have combined EIT images with SOHO/MDI magnetograms and data from other other instruments, and compared our observations with predictions from various eruption scenarios, in particular the "breakout" (Antiochos 1998), "tether cutting" (e.g., Moore et al. 2001), and MHD instability mechanisms. Here we present a representative example of a quiet-region eruption involving a filament ejection, that occurred on 2001 February 28 in a magnetically quadrupolar region and produced a halo CME in SOHO/LASCO images. In addition to EIT and MDI, we analyzed spectral data from SOHO/CDS and soft X-ray (SXR) images from Yohkoh/SXT. We found that flux emergence occurred near one end of the filament, and that both this emergence and resulting microflaring in SXRs and EUV were temporally and spatially closely related to the start of the filament's slow rise. Intensity changes (dimmings and brightenings) in the EIT and SXT images indicate that fields far removed from the erupting core were involved in the eruption, and that breakout-type reconnection did occur. Our observations allow us to investigate whether breakout was the trigger of the eruption, or merely a consequence of a more fundamental eruption process such as tether cutting or MHD instability occurring in a complex magnetic environment.

Sterling, A. C.; Moore, R. L.; Harra, L. K.

2006-01-01

259

Substorms and polar cap convection: the 10 January 2004 interplanetary CME case  

NASA Astrophysics Data System (ADS)

The expansion-contraction model of Dungey cell plasma convection has two different convection sources, i.e. reconnections at the magnetopause and in the magnetotail. The spatial-temporal structure of the nightside source is not yet well understood. In this study we shall identify temporal variations in the winter polar cap convection structure during substorm activity under steady interplanetary conditions. Substorm activity (electrojets and particle precipitations) is monitored by excellent ground-satellite DMSP F15 conjunctions in the dusk-premidnight sector. We take advantage of the wide latitudinal coverage of the IMAGE chain of ground magnetometers in Svalbard - Scandinavia - Russia for the purpose of monitoring magnetic deflections associated with polar cap convection and substorm electrojets. These are augmented by direct observations of polar cap convection derived from SuperDARN radars and cross-track ion drift observations during traversals of polar cap along the dusk-dawn meridian by spacecraft DMSP F13. The interval we study is characterized by moderate, stable forcing of the magnetosphere-ionosphere system (EKL = 4.0-4.5 mV m-1; cross polar cap potential (CPCP), ? (Boyle) = 115 kV) during Earth passage of an interplanetary CME (ICME), choosing an 4-h interval where the magnetic field pointed continuously south-west (Bz < 0; By < 0). The combination of continuous monitoring of ground magnetic deflections and the F13 cross-track ion drift observations in the polar cap allows us to infer the temporal CPCP structure on time scales less than the ~10 min duration of F13 polar cap transits. We arrived at the following estimates of the dayside and nightside contributions to the CPCP (CPCP = CPCP/day + CPCP/night) under two intervals of substorm activity: CPCP/day ~110 kV; CPCP/night ~50 kV (45% CPCP increase during substorms). The temporal CPCP structure during one of the substorm cases resulted in a dawn-dusk convection asymmetry measured by DMSP F13 which is opposite to that expected from the prevailing negative By polarity of the ICME magnetic field, a clear indication of a nightside source.

Andalsvik, Y.; Sandholt, P. E.; Farrugia, C. J.

2012-01-01

260

Use of Yohkoh SXT in Measuring the Net Current and CME Productivity of Active Regions  

NASA Technical Reports Server (NTRS)

In our investigation of the correlation of global nonpotentiality of active regions to their CME productivity (Falconer, D.A. 2001, JGR, in press, and Falconer, Moore, & Gary, 2000, EOS 82, 20 S323), we use Yohkoh SXT images for two purposes. The first use is to help resolve the 180 degree ambiguity in the direction of the observed transverse magnetic field. Resolution of the 180 degree ambiguity is important, since the net current, one of our measures of global nonpotentiality, is derived from integrating the dot product of the transverse field around a contour (I(sub N)=(integral)BT(raised dot)dl). The ambiguity results from the observed transverse field being determined from the linear polarization, which gives the plane of the direction, but leaves a 180 degrees ambiguity. Automated methods to resolve the ambiguity ranging from the simple acute angle rule (Falconer, D.A. 2001) to the more sophisticated annealing method (Metcalf T.R. 1994). For many active regions, especially ones that are nearly potential these methods work well. But for very nonpotential active regions where the shear angle (the angle between the observed and potential transverse field) is near 90 degrees throughout large swaths along the main neutral line, both methods can resolve the ambiguity incorrectly for long segments of the neutral line. By determining from coronal images, such as those from Yohkoh/SXT, the sense of shear along the main neutral line in the active region, these cases can be identified and corrected by a modification of the acute angle rule described here. The second use of Yohkoh/SXT in this study is to check for the cusped coronal arcades of long-duration eruptive flares. This signature is an excellent proxy for CMEs, and was used by Canfield, Hudson, and McKenzie (1999 GRL V26, 6, 627-630). This work is funded by NSF through the Space Weather Program and by NASA through the Solar Physics Supporting Research and Technology Program.

Falconer, D. A.; Moore, R. L.; Gary, G. A.; Six, N. Frank (Technical Monitor)

2001-01-01

261

Comparison of chorus wave power during CIR versus CME-driven geomagnetic storms  

NASA Astrophysics Data System (ADS)

One of the major outstanding scientific problems in the field of heliophysics is understanding and quantifying the dominant source and loss processes that contribute to the variability of relativistic electron populations in the Earth's outer radiation belt. It is known that the dynamics of the outer belt is highly dependent on the driving solar wind conditions during and in the aftermath of geomagnetic storms. For example, geomagnetic storms driven by corotating interaction regions (CIRs) and the following high speed stream (HSS) are particularly efficient at coupling energy into the magnetosphere. Despite the fact that CIR/HSS-driven storms have on average a weaker Dst signature than storms driven by coronal mass ejections (CMEs), these storms typically result in significant outer belt flux enhancements. One process that is believed to play a major role in the evolution of the outer belt is cyclotron-resonant wave particle interactions involving whistler-mode chorus emissions. Chorus interactions can result in the precipitative loss of electrons over a wide range of energy as well as the acceleration of seed electrons (10's to 100's of keV) up to energies of an MeV or greater. Progress in quantifying the role of chorus in radiation belt dynamics requires knowledge of how the chorus wave power varies with time and space as a function of solar wind and magnetospheric conditions. While in situ measurements of chorus are relatively sparse during solar cycle 23, a large database of ground-based ELF/VLF observations from Antarctica exist for this period. Here we examine the variation of chorus activity observed on the ground during a set of geomagnetic storms from 2000 to 2010. We analyze data from Palmer Station, Antarctica (?=-50o) and South Pole Station, Antarctica (?=-74o) thus covering waves generated in the inner magnetosphere as well as in the dayside outer magnetosphere. We explore differences in the intensity, duration and spectral extent of chorus between CIR/HSS-driven storms and CME-driven storms, and we put the results in the context of the global magnetospheric response such as differences in substorm activity and plasmasheet density and temperature.

Spasojevic, M.; Golden, D. I.

2011-12-01

262

A Parametric Study of Erupting Flux Rope Rotation: Modeling the 'Cartwheel CME' on 9 April 2008  

NASA Technical Reports Server (NTRS)

The rotation of erupting filaments in the solar corona is addressed through a parametric simulation study of unstable, rotating flux ropes in bipolar force-free initial equilibrium. The Lorentz force due to the external shear-field component and the relaxation of tension in the twisted field are the major contributors to the rotation in this model, while reconnection with the ambient field is of minor importance, due to the field's simple structure. In the low-beta corona, the rotation is not guided by the changing orientation of the vertical field component's polarity inversion line with height. The model yields strong initial rotations which saturate in the corona and differ qualitatively from the profile of rotation vs. height obtained in a recent simulation of an eruption without preexisting flux rope. Both major mechanisms writhe the flux rope axis, converting part of the initial twist helicity, and produce rotation profiles which, to a large part, are very similar within a range of shear-twist combinations. A difference lies in the tendency of twist-driven rotation to saturate at lower heights than shear-driven rotation. For parameters characteristic of the source regions of erupting filaments and coronal mass ejections, the shear field is found to be the dominant origin of rotations in the corona and to be required if the rotation reaches angles of order 90 degrees and higher; it dominates even if the twist exceeds the threshold of the helical kink instability. The contributions by shear and twist to the total rotation can be disentangled in the analysis of observations if the rotation and rise profiles are simultaneously compared with model calculations. The resulting twist estimate allows one to judge whether the helical kink instability occurred. This is demonstrated for the erupting prominence in the "Cartwheel CME" on 9 April 2008, which has shown a rotation of approximately 115 deg. up to a height of 1.5 Solar R above the photosphere. Out of a range of initial equilibria which include strongly kink-unstable (Phi = 5 pi), weakly kink-unstable (Phi = 3.5 pi), and kink-stable (Phi = 2.5 pi) configurations, only the evolution of the weakly kink-unstable flux rope matches the observations in their entirety.

Kliem, B.; Toeroek, T.; Thompson, W. T.

2012-01-01

263

Typical CME-IP shock events during the ascending phase of Solar Cycle 24 and their arrival time predictions at Earth  

NASA Astrophysics Data System (ADS)

Predicting arrival times of interplanetary (IP) shocks at the near Earth space is an important ingredient of space weather forecasting because the passage of an IP shock at Earth will compress the magnetosphere and produce corresponding space weather effects. We have developed a new shock arrival time prediction model, called SPM2, based on 551 solar disturbance events during Solar Cycle 23. Here new shock events in Solar Cycle 24 will be used to check the predicting performance of SPM2. 35 typical CME-IP shock events during the ascending phase of Solar Cycle 24 (2009-2013) with near-simultaneous coronagraph observations of CMEs and metric type II radio bursts are adopted as the sample events. Comparisons between the initial shock speed calculated from the type II burst drifting rate and the CME speed derived from coronagraph observations are investigated. It is found that the multi-spacecraft coronagraph observations combined with appropriate CME leading edge fitting model can give a more reliable CME radial speed than the type II burst shock speed. Then, SPM2 and an empirical model, which input the type II shock speed and CME speed respectively, are used to give the arrival time prediction of the associated IP shocks at the Earth orbit. The predicting precision of the empirical model would become better if the CME is tracked to a larger helio-distance. The prediction of SPM2 gives a similar predicting accuracy even its input parameters contain larger uncertainties. On this sense, the potential capability of the SPM2 model is also discussed in terms of real-time shock arrival time forecasts.

Zhao, X.; Feng, X.

2013-12-01

264

Transcriptional Regulation of the CmeABC Multidrug Efflux Pump and the KatA Catalase by CosR in Campylobacter jejuni  

PubMed Central

CosR is an essential response regulator in Campylobacter jejuni, a major food-borne pathogen causing enteritis worldwide. A transcriptomic analysis performed in this study discovered 93 genes whose transcriptional levels were changed >2-fold due to the repression of CosR expression by antisense peptide nucleic acid. The identified CosR-regulated genes are involved in various cellular functions, such as energy production, protein synthesis and folding, flagellum biogenesis, and lipid metabolism. Interestingly, 17 of the 93 CosR-regulated genes (18.3%) are predicted essential genes, indicating that CosR may participate in the regulation of vital biological processes in C. jejuni. In particular, CosR knockdown increased the transcriptional levels of cmeA, cmeB, and cmeC genes, whose protein product (CmeABC) is an important determinant conferring multidrug resistance in Campylobacter. Negative regulation of cmeABC by CosR was verified by quantitative real-time PCR (qRT-PCR) and PcmeABC::lacZ assay. The results of electrophoretic mobility shift assays (EMSAs) and DNase I footprinting assays demonstrated that CosR directly binds to the cmeABC promoter. Another notable finding is that CosR regulates the transcription of katA, the sole catalase gene in C. jejuni. Further characterization with qRT-PCR, the catalase enzyme assay, EMSA, and DNase I footprinting assays successfully demonstrated that CosR affects the katA transcription and the catalase activity by direct interactions with the katA promoter. The findings in this study clearly demonstrated that CosR regulates resistance mechanisms in C. jejuni by controlling the expression of genes involved in oxidative stress defense and extrusion of toxic compounds out of the cell.

Hwang, Sunyoung; Zhang, Qijing; Ryu, Sangryeol

2012-01-01

265

Determination of coronal magnetic fields from 10 to 26 R ? using the density compression ratios of CME-driven shocks  

NASA Astrophysics Data System (ADS)

Recently, the estimation of coronal magnetic field using new methods, such as standoff distance method or density compression ratio method has been reported. In the present work, we utilized the density compression ratio of CME-driven shocks for 10 events at 29 different locations in the upper solar corona (10-26 R ?) and determined the coronal magnetic field for two different adiabatic indices ( ?=4/3 and 5/3). In addition, radial dependence of shock parameters in the corona is studied. It is found that the magnetic field estimated in the above range agree with the general trend. In addition, we obtained a radial profile of magnetic field [ B( R)=623 R -1.4] in the entire upper corona (3-30 R ?) by combining the magnetic field estimated by Kim et al. (Astrophys. J. 746:118, 2012) in the range 3-15 R ? and that estimated in the present study in the range (10-26 R ?). The power-law indices are nearly in agreement with recent results of CME-driven shocks reported in the literature. The results are discussed with the comparison of newly reported coronal magnetic field values obtained by different techniques and found that the power-law relation closely follow the literature values.

Shanmugaraju, A.; Suresh, K.; Moon, Y.-J.

2014-05-01

266

Cytosolic Delivery of Granzyme B by Bacterial Toxins: Evidence that Endosomal Disruption, in Addition to Transmembrane Pore Formation, Is an Important Function of Perforin  

PubMed Central

Granule-mediated cell killing by cytotoxic lymphocytes requires the combined actions of a membranolytic protein, perforin, and granule-associated granzymes, but the mechanism by which they jointly kill cells is poorly understood. We have tested a series of membrane-disruptive agents including bacterial pore-forming toxins and hemolytic complement for their ability to replace perforin in facilitating granzyme B-mediated cell death. As with perforin, low concentrations of streptolysin O and pneumolysin (causing <10% 51Cr release) permitted granzyme B-dependent apoptosis of Jurkat and Yac-1 cells, but staphylococcal alpha-toxin and complement were ineffective, regardless of concentration. The ensuing nuclear apoptotic damage was caspase dependent and included cleavage of poly(ADP-ribose) polymerase, suggesting a mode of action similar to that of perforin. The plasma membrane lesions formed at low dose by perforin, pneumolysin, and streptolysin did not permit diffusion of fluorescein-labeled proteins as small as 8 kDa into the cell, indicating that large membrane defects are not necessary for granzymes (32 to 65 kDa) to enter the cytosol and induce apoptosis. The endosomolytic toxin, listeriolysin O, also effected granzyme B-mediated cell death at concentrations which produced no appreciable cell membrane damage. Cells pretreated with inhibitors of endosomal trafficking such as brefeldin A took up granzyme B normally but demonstrated seriously impaired nuclear targeting of granzyme B when perforin was also added, indicating that an important role of perforin is to disrupt vesicular protein trafficking. Surprisingly, cells exposed to granzyme B with perforin concentrations that produced nearly maximal 51Cr release (1,600 U/ml) also underwent apoptosis despite excluding a 8-kDa fluorescein-labeled protein marker. Only at concentrations of >4,000 U/ml were perforin pores demonstrably large enough to account for transmembrane diffusion of granzyme B. We conclude that pore formation may allow granzyme B direct cytosolic access only when perforin is delivered at very high concentrations, while perforin’s ability to disrupt endosomal trafficking may be crucial when it is present at lower concentrations or in killing cells that efficiently repair perforin pores.

Browne, Kylie A.; Blink, Elizabeth; Sutton, Vivien R.; Froelich, Christopher J.; Jans, David A.; Trapani, Joseph A.

1999-01-01

267

Cytosolic delivery of granzyme B by bacterial toxins: evidence that endosomal disruption, in addition to transmembrane pore formation, is an important function of perforin.  

PubMed

Granule-mediated cell killing by cytotoxic lymphocytes requires the combined actions of a membranolytic protein, perforin, and granule-associated granzymes, but the mechanism by which they jointly kill cells is poorly understood. We have tested a series of membrane-disruptive agents including bacterial pore-forming toxins and hemolytic complement for their ability to replace perforin in facilitating granzyme B-mediated cell death. As with perforin, low concentrations of streptolysin O and pneumolysin (causing <10% (51)Cr release) permitted granzyme B-dependent apoptosis of Jurkat and Yac-1 cells, but staphylococcal alpha-toxin and complement were ineffective, regardless of concentration. The ensuing nuclear apoptotic damage was caspase dependent and included cleavage of poly(ADP-ribose) polymerase, suggesting a mode of action similar to that of perforin. The plasma membrane lesions formed at low dose by perforin, pneumolysin, and streptolysin did not permit diffusion of fluorescein-labeled proteins as small as 8 kDa into the cell, indicating that large membrane defects are not necessary for granzymes (32 to 65 kDa) to enter the cytosol and induce apoptosis. The endosomolytic toxin, listeriolysin O, also effected granzyme B-mediated cell death at concentrations which produced no appreciable cell membrane damage. Cells pretreated with inhibitors of endosomal trafficking such as brefeldin A took up granzyme B normally but demonstrated seriously impaired nuclear targeting of granzyme B when perforin was also added, indicating that an important role of perforin is to disrupt vesicular protein trafficking. Surprisingly, cells exposed to granzyme B with perforin concentrations that produced nearly maximal (51)Cr release (1,600 U/ml) also underwent apoptosis despite excluding a 8-kDa fluorescein-labeled protein marker. Only at concentrations of >4,000 U/ml were perforin pores demonstrably large enough to account for transmembrane diffusion of granzyme B. We conclude that pore formation may allow granzyme B direct cytosolic access only when perforin is delivered at very high concentrations, while perforin's ability to disrupt endosomal trafficking may be crucial when it is present at lower concentrations or in killing cells that efficiently repair perforin pores. PMID:10567584

Browne, K A; Blink, E; Sutton, V R; Froelich, C J; Jans, D A; Trapani, J A

1999-12-01

268

Transdermal drug delivery  

PubMed Central

Transdermal drug delivery has made an important contribution to medical practice, but has yet to fully achieve its potential as an alternative to oral delivery and hypodermic injections. First-generation transdermal delivery systems have continued their steady increase in clinical use for delivery of small, lipophilic, low-dose drugs. Second-generation delivery systems using chemical enhancers, non-cavitational ultrasound and iontophoresis have also resulted in clinical products; the ability of iontophoresis to control delivery rates in real time provides added functionality. Third-generation delivery systems target their effects to skin’s barrier layer of stratum corneum using microneedles, thermal ablation, microdermabrasion, electroporation and cavitational ultrasound. Microneedles and thermal ablation are currently progressing through clinical trials for delivery of macromolecules and vaccines, such as insulin, parathyroid hormone and influenza vaccine. Using these novel second- and third-generation enhancement strategies, transdermal delivery is poised to significantly increase impact on medicine.

Prausnitz, Mark R.; Langer, Robert

2009-01-01

269

A Novel 3D Supramolecular Network Constructed from (Cu(4,4?-bipyridine)(O2CMe)2)2 Molecular Ladders by Hydrogen Bonding  

Microsoft Academic Search

The title complex, {(Cu2(4,4?-bipyridine)2(µ-O2CMe)2(O2CMe)2)?H2O}n 1, was synthesized and structurally characterized by X-ray crystallography. It crystallizes in monoclinic, space group C2\\/c with a = 13.4474(5), b = 11.7566(2), c = 19.5380(6) Å, ? = 92.930(2)°, V = 3084.84(16) Å 3 , Z = 4, Cu2C28N4O9H30, Mr = 693.64, Dc = 1.494 g\\/cm 3 , F(000) = 1424 and µ(MoKa) = 1.436

YANG E; WANG Xiao-Qin; QIN Ye-Yan

270

An operational software tool for the analysis of coronagraph images: Determining CME parameters for input into the WSA-Enlil heliospheric model  

NASA Astrophysics Data System (ADS)

Coronal mass ejections (CMEs)—massive explosions of dense plasma that originate in the lower solar atmosphere and propagate outward into the solar wind—are the leading cause of significant space weather effects within Earth's environment. Computational models of the heliosphere such as WSA-Enlil offer the possibility of predicting whether a given CME will become geo-effective and, if so, the likely time of arrival at Earth. To be meaningful, such a forecast model is dependent upon accurately characterizing key parameters for the CME, notably its speed and direction of propagation, and its angular width. Studies by Zhao et al. (2002) and Xie et al. (2004) suggest that these key CME parameters can be deduced from geometric analysis of the elliptical "halo" forms observed in coronagraph images on spacecraft such as the Solar and Heliospheric Observatory (SOHO) and which result from a CME whose propagation is roughly toward or away from the observer. Both studies assume that the CME presents a circular cross-section and maintains a constant angular width during its radial expansion, the so called "cone model." Development work at the NOAA Space Weather Prediction Center (SWPC) has been concerned with building and testing software tools to allow forecasters to determine these CME parameters routinely within an operational context, a key aspect of transitioning the WSA-Enlil heliospheric model into operations at the National Weather Service. We find "single viewpoint" cone analysis, while a useful start, to be highly problematic in many real-world situations. In particular, it is extremely difficult to establish objectively the correct ellipse that should be applied to a given halo form and that small changes in the exact ellipse chosen can lead to large differences in the deduced CME parameters. The inaccuracies in the technique are particularly evident for analysis of the "nearly circular" elliptical forms which result from CMEs that are propagating directly toward the observer and are therefore the most likely to be geo-effective. In working to resolve this issue we have developed a new three-dimensional (3-D) graphics-based analysis system which seeks to reduce inaccuracies by analyzing a CME using coronagraph images taken concurrently by SOHO and also by the two Solar TErrestrial RElations Observatory (STEREO) spacecraft, which provide additional viewing locations well away from the Sun-Earth line. The resulting "three view" technique has led to the development of the CME Analysis Tool (CAT), an operational software system in routine use at the SWPC as the primary means to determine CME parameters for input into the WSA-Enlil model. Results from the operational WSA-Enlil system are presented: utilizing CAT to provide CME input parameters, we show that, during the first year of operations at SWPC, the WSA-Enlil model has forecasted the arrival of CMEs at Earth with an average error 7.5 h.

Millward, G.; Biesecker, D.; Pizzo, V.; Koning, C. A.

2013-02-01

271

The First Ground Level Enhancement Event of Solar Cycle 24: Direct Observation of Shock Formation and Particle Release Heights  

NASA Astrophysics Data System (ADS)

We report on the 2012 May 17 ground level enhancement (GLE) event, which is the first of its kind in solar cycle 24. This is the first GLE event to be fully observed close to the surface by the Solar Terrestrial Relations Observatory (STEREO) mission. We determine the coronal mass ejection (CME) height at the start of the associated metric type II radio burst (i.e., shock formation height) as 1.38 Rs (from the Sun center). The CME height at the time of GLE particle release was directly measured from a STEREO image as 2.32 Rs, which agrees well with the estimation from CME kinematics. These heights are consistent with those obtained for cycle-23 GLEs using back-extrapolation. By contrasting the 2012 May 17 GLE with six other non-GLE eruptions from well-connected regions with similar or larger flare sizes and CME speeds, we find that the latitudinal distance from the ecliptic is rather large for the non-GLE events due to a combination of non-radial CME motion and unfavorable solar B0 angle, making the connectivity to Earth poorer. We also find that the coronal environment may play a role in deciding the shock strength.

Gopalswamy, N.; Xie, H.; Akiyama, S.; Yashiro, S.; Usoskin, I. G.; Davila, J. M.

2013-03-01

272

Delivery Performance Indicators.  

National Technical Information Service (NTIS)

Delivery of equipment in accordance with the user's required schedule is essential to DARCOM's materiel readiness mission. However, DARCOM is experiencing increasing problems with delinquent deliveries. For DARCOM's major subordinate activities, delinquen...

H. F. Candy R. C. Brannon S. H. Carter

1977-01-01

273

Cloning of an auxin-responsive 1-aminocyclopropane-1-carboxylate synthase gene (CMe-ACS2) from melon and the expression of ACS genes in etiolated melon seedlings and melon fruits.  

PubMed

Two cDNA fragments (pCMe-ACS2 and 3) encoding auxin-responsive 1-aminocyclopropane-1-carboxylate synthase (ACS; EC.4.4.1.14) have been isolated from melon, and the expression patterns of the genes in etiolated melon seedlings and melon fruit have been determined by RT-PCR analysis. The deduced amino acid sequences of pCMe-ACS2 and 3 were homologous to those of AT-ACS6 and 4, which were auxin-responsive ACS genes of Arabidopsis. Both CMe-ACS2 and 3 were auxin-responsive ACS genes and their expressions in roots and hypocotyls were induced by treatment with indole acetic acid (IAA, 100 µM). The mRNA level of CMe-ACS2 in the fruit increased after pollination. Those of both CMe-ACS2 and 3 temporarily increased in the mesocarp tissues at the preclimacteric stage (from day 3 to day 5 after harvest) during ripening, while that of CMe-ACS3 was lower than that of CMe-ACS2. The increase in the mRNA level of CMe-ACS1 (wound- and ripening-induced gene, T. Miki, M. Yamamoto, N. Nakagawa, O. Ogura, H. Mori, H. Imaseki, T. Sato, Nucleotide sequence of a cDNA for 1-aminocyclopropane-1-carboxylate synthase from melon fruits, Plant Physiol. 107 (1995) 297-298.) in the mesocarp tissue was not observed until 5 days after harvest. A genomic DNA encoding CMe-ACS2 was isolated and its nucleotide sequence was determined. Nucleotide sequences resembling the auxin-responsive elements (AuxRE) D1 and D4 (the TGTCTC element) in the GH3 gene from soybean, and the auxin-responsive domain (AuxRD) B in PS-IAA4/5 from pea were found in the 5'-flanking region of the CMe-ACS2 gene. PMID:11074269

Ishiki; Oda; Yaegashi; Orihara; Arai; Hirabayashi; Nakagawa; Sato

2000-11-01

274

Articulating feedstock delivery device  

DOEpatents

A fully articulable feedstock delivery device that is designed to operate at pressure and temperature extremes. The device incorporates an articulating ball assembly which allows for more accurate delivery of the feedstock to a target location. The device is suitable for a variety of applications including, but not limited to, delivery of feedstock to a high-pressure reaction chamber or process zone.

Jordan, Kevin

2013-11-05

275

Effect of an efflux pump inhibitor on the function of the multidrug efflux pump CmeABC and antimicrobial resistance in Campylobacter.  

PubMed

CmeABC, a multidrug efflux pump, contributes to the resistance of Campylobacter to a broad range of antimicrobials. We hypothesize that an efflux pump inhibitor (EPI) may inhibit the function of CmeABC and control antibiotic resistance in Campylobacter. In this study, we examined the effect of EPI Phe-Arg beta-naphthyl-amide dihydrochloride (MC-207,110) on the susceptibility of Campylobacter to various antimicrobials. The presence of the EPI resulted in a 2- to 2048-fold reduction in the minimum inhibitory concentration (MIC) of antimicrobials known to be substrates of the CmeABC pump in all Campylobacter strains. Both intrinsic and acquired resistance of C. jejuni to erythromycin was decreased drastically (64- to 128-fold reduction in the MIC) in the presence of the EPI while the MICs of fluoroquinolones were only slightly decreased (2- to 4-fold). Examination of 57 Campylobacter isolates from various origins further demonstrated that MC-207,110 decreased the MICs of erythromycin (2- to 512-fold) in all isolates. Compared to wild-type strains, the isogenic CmeB mutants displayed smaller magnitudes of reduction in the MICs of antimicrobials in the presence of the EPI, indicating the inhibitory effect of the EPI is primarily CmeABC-dependent. The inhibitory effect of MC-207,110 was also dose-dependent, and as little as 0.5 microg/mL of the EPI resulted in a decreased MIC for erythromycin in C. jejuni. More importantly, the presence of MC-207,110 decreased the frequency of emergence of erythromycin-resistant mutants in C. jejuni (<10(11), well below the normal frequency of approximately 10(8)). Together, these findings indicate that EPI MC-207,110 inhibits the function of CmeABC efflux pump and potentiates the activity of antibiotics against Campylobacter. Inhibition of CmeABC by EPI is a promising approach in combating antibiotic resistance of Campylobacter in humans and animal reservoirs. PMID:17199521

Martinez, Ad'Lynn; Lin, Jun

2006-01-01

276

Correlation of the CME Productivity of Solar Active Regions with Measures of their Global Nonpotentiality from Vector Magnetograms: Baseline Results  

NASA Technical Reports Server (NTRS)

From conventional magnetograms and chromospheric and coronal images, it is known qualitatively that the fastest coronal mass ejections (CMEs) are magnetic explosions from sunspot active regions in which the magnetic field is globally strongly sheared and twisted from its minimum-energy potential configuration. In this paper, we present measurements from active-region vector magnetograms that begin to quantify the dependence of the CME productivity of an active region on the global nonpotentiality of its magnetic field. From each of 17 magnetograms of 12 bipolar active regions, we obtain a measure of the size of the active region (the magnetic flux content, phi) and three different measures of the global nonpotentiality (L(sub SS), the length of strong-shear, strong-field main neutral line; I(sub N), the net electric current arching from one polarity to the other; and alpha = muI(subN/phi), a flux-normalized measure of the field twist).

Falconer, David A.; Moore, Ron L.; Gary, G. Allen; Six, N. Frank (Technical Monitor)

2001-01-01

277

Conventional topical delivery systems.  

PubMed

Effective dermatologic therapy depends on both the active drug and the properties of the delivery system. A topical delivery system, or vehicle, is defined as the substance that carries a specific drug into contact with and through the skin. The challenge to topical drug delivery is the transport across the skin barrier. Depending on the delivery system, penetration of the active drug can be quite variable and this is largely due to the physiochemical properties of the constituent components of that vehicle. Selection of the appropriate drug delivery system will depend on the active, anatomic site of disease and patient preferences. PMID:22353153

Weiss, Stefan C

2011-01-01

278

Determination of the cobpoint evolution using 3D MHD simulations for the propagation of CME-driven shocks  

NASA Astrophysics Data System (ADS)

Particle flux profile of large solar energetic particle (SEP) events depends on several factors, such as the strength and geometry of the associated CME-driven shock, the relative position of the observer with respect to the leading direction of the travelling shock, the conditions for the particle acceleration, the injection and the transport throughout the interplanetary space, and the particle energy. In this study we focus on two of these factors: the influence of the shock and the relative position of the observer. We performed a 3D simulation of the propagation of a coronal/interplanetary CME-driven shock from the Sun up to 1 AU in the framework of ideal MHD using the Versatile Advection Code (Toth et al., 1996). Three spacecrafts are located at 1 AU at different longitudes with respect to the nose of the shock. We study the evolution of the plasma conditions in the shock front region magnetically connected to each spacecraft, that is, the region of the shock front scanned by the cobpoint (Heras et al., 1995) as the shock propagates away from the Sun. The conclusions about the influence of these changing conditions on the injection rate of shock-accelerated particles are presented. References Toth, G. A General Code for Modelling MHD flows on Parallel Computers: Versatile Advection Code, Astrophys. Lett. and Comm., 34, 245, 1996. Heras, A.M., Sanahuja, B., Lario, D., et al. Three low-energy particle events: modeling the influence of the parent interplanetary shock. Astrophys. J. 445, 497-508, 1995.

Rodriguez-Gasen, Rosa; Aran, Angels; Sanahuja, Blai; Jacobs, Carla; Poedts, Stefaan

279

The CME/ICME relationship for the 3-5 April 2010 and Aug 1-4 2010 events  

NASA Astrophysics Data System (ADS)

For two coronal mass ejections (CMEs) associated with interplanetary CMEs (ICMEs) causing moderate geomagnetic storms in 2010, we discuss properties such as interplanetary propagation, orientation and arrival time calculation. We study heliospheric images of the CMEs provided by STEREO / HI in combination with in situ observations by the Wind spacecraft near Earth. The 3-5 April 2010 event was the first fast (800 km/s) ICME including a magnetic cloud observed by both the STEREO/HI instruments and a near Earth spacecraft. During the subsequent geomagnetic storm (minimum Dst = -72 nT, maximum Kp = 8-), communication with the Galaxy 15 satellite was lost. Using forward modeling in combination with HI techniques and the in situ velocity, we show that the ICME did not decelerate much between Sun and Earth. Earth was not hit directly, but the ICME flank was responsible for a long storm growth phase. The magnetic cloud (MC) inside the ICME cannot be modeled with approaches assuming an invariant direction. These observations confirm the hypotheses that parts of ICMEs classified as (1) long-duration MCs or (2) magnetic-cloud-like (MCL) structures can be a consequence of a spacecraft trajectory through the ICME flank. The 1-4 Aug 2010 events consisted of several CMEs accompanied by multiple ICME signatures near Earth, responsible for a two-step geomagnetic storm. We discuss which of the ICMEs correspond to the flare/filaments/CMEs observed by STEREO/COR/HI and SDO HMI/AIA observed closer to the Sun. We apply reconstruction methods to estimate the local flux rope orientation and other properties. The ICME signatures are linked to HI observations of the CME fronts, which yields full CME kinematics between the Sun and Earth. STEREO Ahead HI1/2 images of the 3-5 April 2010 Earth-directed coronal mass ejection.

Moestl, C.; Temmer, M.; Rollett, T.; Kilpua, E. K.; Farrugia, C. J.; Veronig, A.; Galvin, A. B.; Biernat, H. K.

2010-12-01

280

Characteristics That Predict Physician Participation in a Web-Based CME Activity: The MI-Plus Study  

PubMed Central

Introduction Physician use of the Internet for practice improvement has increased dramatically over the last decade, but research shows that many physicians choose not to participate. The current study investigated the association of specific physician characteristics with enrollment rates and intensity of participation in a specific Internet-delivered educational intervention to improve care to post–myocardial infarction (MI) patients. Methods Primary-care physicians were recruited for participation in a randomized controlled trial designed to compare effectiveness of an intervention Web site versus a control Web site in the management of adult chronic disease. Physicians were informed that the intervention focused on ambulatory post–myocardial infarction patients. Physician characteristics were obtained from a commercial vendor with data merged from the American Medical Association and Alabama State Licensing Board. Enrollment and Web use were tracked electronically. Results Out of a sample of 1337 eligible physicians, 177 (13.2%) enrolled in the study. Enrollment was higher for physicians with more post-MI patients (?20 vs < 20 patients, 15.3% vs 9.3%, P = .002) and for those practicing in rural compared to urban areas (16.3% vs 12.1%, P = .046). Intensity of use of the Internet courses after initial enrollment was not predicted by physician characteristics in the current sample. Discussion Physicians with more post-MI patients and rural practice location were found to predict enrollment in an Internet-delivered continuing medical education (CME) intervention designed to improve care for post-MI patients. These factors predicted program interest but not program use. More research is needed to replicate these findings to investigate variables that determine physician engagement in Internet CME.

Schoen, Michael J.; Tipton, Edmond F.; Houston, Thomas K.; Funkhouser, Ellen; Levine, Deborah A.; Estrada, Carlos A.; Allison, Jeroan J.; Williams, O. Dale; Kiefe, Catarina I.

2011-01-01

281

Colon drug delivery.  

PubMed

Oral drug delivery to the colon has attracted significant attention during the past 20 years. Colon targeting is recognised to have several therapeutic advantages, such as the oral delivery of drugs that are destroyed by the stomach acid and/or metabolised by pancreatic enzymes. Sustained colonic release of drugs can be useful in the treatment of nocturnal asthma, angina and arthritis. Local treatment of colonic pathologies, such as ulcerative colitis, colorectal cancer and Crohn's disease, is more effective with the delivery of drugs to the affected area. Likewise, colonic delivery of vermicides and colonic diagnostic agents requires smaller doses. This article aims to provide an insight into the design and manufacturing considerations, and an evaluation of colonic drug delivery systems in order to understand why there are still few delivery technologies that have reached the market, despite intensive research in this field. For this purpose, various approaches to colon-specific drug delivery are discussed. PMID:16370944

Van den Mooter, Guy

2006-01-01

282

Intracochlear Drug Delivery Systems  

PubMed Central

Introduction Advances in molecular biology and in the basic understanding of the mechanisms associated with sensorineural hearing loss and other diseases of the inner ear, are paving the way towards new approaches for treatments for millions of patients. However, the cochlea is a particularly challenging target for drug therapy, and new technologies will be required to provide safe and efficacious delivery of these compounds. Emerging delivery systems based on microfluidic technologies are showing promise as a means for direct intracochlear delivery. Ultimately, these systems may serve as a means for extended delivery of regenerative compounds to restore hearing in patients suffering from a host of auditory diseases. Areas covered in this review Recent progress in the development of drug delivery systems capable of direct intracochlear delivery is reviewed, including passive systems such as osmotic pumps, active microfluidic devices, and systems combined with currently available devices such as cochlear implants. The aim of this article is to provide a concise review of intracochlear drug delivery systems currently under development, and ultimately capable of being combined with emerging therapeutic compounds for the treatment of inner ear diseases. Expert Opinion Safe and efficacious treatment of auditory diseases will require the development of microscale delivery devices, capable of extended operation and direct application to the inner ear. These advances will require miniaturization and integration of multiple functions, including drug storage, delivery, power management and sensing, ultimately enabling closed-loop control and timed-sequence delivery devices for treatment of these diseases.

Borenstein, Jeffrey T.

2011-01-01

283

Formation of slow shock pairs associated with coronal mass ejections  

NASA Astrophysics Data System (ADS)

The formation of a forward-reverse slow shock pair in the solar corona is presently simulated by an MHD model that uses the Rankine-Hugoniot solution to calculate the flow-property jumps at all shock crossings. The shocks divide the solution-domain into several continuous flow regions whose respective governing characteristics are solved by the method of characteristics. The plasma impact compresses the plasma near the front of the coronal mass ejection (CME); as the CME-associated slow shock pair moves outwards in interplanetary space, it evolves into a pair of fast shocks. All three phenomena are eventually manifested in interplanetary space as a magnetic cloud accompanied by a fast shock pair, with a forward shock preceding the cloud and a reverse shock appearing either within or behind the cloud.

Whang, Y. V.

284

Commercial Document Delivery Services "Challenged" as EBSCO Drops Service.  

ERIC Educational Resources Information Center

Discusses the EBSCO decision to stop its traditional commercial document delivery business. High prices for copyright clearance, government subsidized services, electronic formats available on the Internet, Web-based services, and consortium-based licensing activities are discussed as influencing the market for document delivery. (LRW)

Machovec, George S.

1998-01-01

285

Microfluidics for Drug Delivery  

Microsoft Academic Search

Drug delivery, i.e. the way a pharmacologically active substance is delivered to the body, has a significant impact on the\\u000a therapeutic value of medication. The paper gives an overview on different drug delivery schemes and describes the limitations\\u000a of the oral route, which is the current gold standard in the market. Following these limitations, plenty of alternative (parenteral)\\u000a drug delivery

S. Haeberle; D. Hradetzky; A. Schumacher; M. Vosseler; S. Messner; R. Zengerle

286

APPLICATIONS OF ELECTROSPINNING TECHNIQUE IN DRUG DELIVERY  

Microsoft Academic Search

Electrospinning has proven to be a simple, versatile, and useful technique for fabricating nanofibers from a rich variety of functional materials. In the past few years, we have witnessed tremendous research progress in understanding electrospinning mechanisms and their applications in controlled drug releasing and delivery. In this review, a brief description of the electrospinning process and fiber formation mechanisms is

Bochu Wang; Yazhou Wang; Tieying Yin; Qingsong Yu

2010-01-01

287

One Quiz File, Several Modes of Delivery  

ERIC Educational Resources Information Center

This report offers online course designers, particularly those keen on using Moodle CMSs, a means of diversifying accessibility to their educational materials via multiple modes of delivery that do not require the creation of numerous files and formats for just one activity. The author has made contributions to the development of an open source…

Herbert, John C.

2012-01-01

288

An Asynchronous Augmentation to Traditional Course Delivery.  

ERIC Educational Resources Information Center

Asynchronous augmentation facilitates distributed learning, which relies heavily on technology and self-learning. This paper reports the results of delivering a real estate principles course using an asynchronous course delivery format. It highlights one of many ways to enhance learning using technology, and it provides information concerning how…

Wolverton, Marvin L.; Wolverton, Mimi

289

Drug delivery systems.  

PubMed

New and emerging drug delivery systems for traditional drugs and the products of biotechnology are discussed, and the role of the pharmacist in ensuring the appropriate use of these systems is outlined. Advantages of advanced drug delivery systems over traditional systems are the ability to deliver a drug more selectively to a specific site; easier, more accurate, less frequent dosing; decreased variability in systemic drug concentrations; absorption that is more consistent with the site and mechanism of action; and reductions in toxic metabolites. Four basic strategies govern the mechanisms of advanced drug delivery: physical, chemical, biological, and mechanical. Oral drug delivery systems use natural and synthetic polymers to deliver the product to a specific region in the gastrointestinal tract in a timely manner that minimizes adverse effects and increases drug efficacy. Innovations in injectable and implantable delivery systems include emulsions, particulate delivery systems, micromolecular products and macromolecular drug adducts, and enzymatic-controlled delivery. Options for noninvasive drug delivery include the transdermal, respiratory, intranasal, ophthalmic, lymphatic, rectal, intravaginal, and intrauterine routes as well as topical application. Rapid growth is projected in the drug delivery systems market worldwide in the next five years. Genetic engineering has mandated the development of new strategies to deliver biotechnologically derived protein and peptide drugs and chemoimmunoconjugates. The role of the pharmacist in the era of advanced drug delivery systems will be broad based, including administering drugs, compounding, calculating dosages based on pharmacokinetic and pharmacodynamic monitoring, counseling, and research. The advent of advanced drug delivery systems offers pharmacists a new opportunity to assume an active role in patient care. PMID:1772110

Robinson, D H; Mauger, J W

1991-10-01

290

Adhesion Prevention in Patients With Multiple Cesarean Deliveries  

Microsoft Academic Search

Adhesion formation is a well-known complication of abdominal surgery. Although one-third of all deliveries in the US are by cesarean delivery (CD), little is known about adhesions in the obstetric setting. Various surgical techniques for reducing adhesion formation following CD have been investigated. The relative benefits of peritoneal closure and single-layer uterine closure are areas of continued research and debate.

Gordon Wright Bates; Stacy Shomento

291

Noninvasive drug delivery  

Microsoft Academic Search

Advances in biopharmaceutical technology have spawned new drug delivery devices and mechanisms. Noninvasive methods, including\\u000a iontophoresis and transmucosal drug delivery, have improved treatment of certain patient population. Their use is discussed\\u000a in the following paper.

Ruth Zimmer; Michael A. Ashburn

2001-01-01

292

Ocular drug delivery.  

PubMed

Ocular drug delivery has been a major challenge to pharmacologists and drug delivery scientists due to its unique anatomy and physiology. Static barriers (different layers of cornea, sclera, and retina including blood aqueous and blood-retinal barriers), dynamic barriers (choroidal and conjunctival blood flow, lymphatic clearance, and tear dilution), and efflux pumps in conjunction pose a significant challenge for delivery of a drug alone or in a dosage form, especially to the posterior segment. Identification of influx transporters on various ocular tissues and designing a transporter-targeted delivery of a parent drug has gathered momentum in recent years. Parallelly, colloidal dosage forms such as nanoparticles, nanomicelles, liposomes, and microemulsions have been widely explored to overcome various static and dynamic barriers. Novel drug delivery strategies such as bioadhesive gels and fibrin sealant-based approaches were developed to sustain drug levels at the target site. Designing noninvasive sustained drug delivery systems and exploring the feasibility of topical application to deliver drugs to the posterior segment may drastically improve drug delivery in the years to come. Current developments in the field of ophthalmic drug delivery promise a significant improvement in overcoming the challenges posed by various anterior and posterior segment diseases. PMID:20437123

Gaudana, Ripal; Ananthula, Hari Krishna; Parenky, Ashwin; Mitra, Ashim K

2010-09-01

293

Synopsis of Diet in Dermatology: A one day CME conducted by the Department of Dermatology, Kasturba Medical College, Manipal, March 3, 2013.  

PubMed

Food is intricately related to mind and body and is one of the elements sustaining life, in disease as well as in health. There are many myths and misgivings regarding partake of food and its medicinal properties. The Department of Dermatology, Kasturba Medical College (KMC), Manipal organized a continuing medical education (CME) on Diet in Dermatology on 3(rd) March 2013 focusing on pertinent issues regarding diet and medicinal use of food. PMID:24350027

Prabhu, Smitha S; Nayak, Sudhir Uk; Shenoi, Shrutakirthi Damodar; Pai, Sathish Ballambat

2013-10-01

294

Novel gene delivery systems  

PubMed Central

Gene therapy is an emerging field in medical and pharmaceutical sciences because of its potential in treating chronic diseases like cancer, viral infections, myocardial infarctions, and genetic disorders. Application of gene therapy is limited because of lack of suitable methods for proper introduction of genes into cells and therefore, this is an area of interest for most of the researchers. To achieve successful gene therapy, development of proper gene delivery systems could be one of the most important factors. Several nonviral and viral gene transfer methods have been developed. Even though the viral agents have a high transferring efficiency, they are difficult to handle due to their toxicity. To overcome the safety problems of the viral counterpart, several nonviral in vitro and in vivo gene delivery systems are developed. Out of these, the most promising and latest systems include polymer-based nonviral gene carriers, dendrimers, and physical means like electroporation, microinjection, etc., Shunning of possible immunogenicity and toxicity, and the feasibility of repeated administration are some of the merits of nonviral gene delivery systems over viral gene delivery. An ideal nonviral gene carrying system should possess all these merits without any compromise to its gene transferring efficiency. The viral gene delivery systems include lytic and nonlytic vectors for drug delivery. Inspite of its toxicity they are still preferred because of their long term expression, stability, and integrity. This review explores the recent developments and relevancy of the novel gene delivery systems in gene therapy.

Manjila, Steffy B; Baby, Jomon N; Bijin, Elambilan N; Constantine, Icey; Pramod, Kannissery; Valsalakumari, Janardhanan

2013-01-01

295

Microsponge delivery system.  

PubMed

Microsponges are polymeric delivery systems consisting of porous microspheres having a size range in between 5 to 300 microm depending upon the degree of smoothness or after feel required for the end formulations. Microsponge Delivery System MDS is a unique technology for controlled delivery of drug. The present review introduces Microsponge technology along with its synthesis, characterization, programmable parameters and release mechanism of MDS. Wide ranges of applications are also suggested to develop drug or cosmetic products with enhanced safety and efficacy. MDS can provide increased efficacy for topically active agents with enhanced safety, extended product stability and improved aesthetic properties in an efficient and novel manner. PMID:17456031

Chadawar, Vikrant; Shaji, Jessy

2007-04-01

296

Neurotrophin delivery using nanotechnology.  

PubMed

Deficits or overexpression of neurotrophins cause neurodegenerative diseases and psychiatric disorders. These proteins are required for the maintenance of the function, plasticity and survival of neurons in the central (CNS) and peripheral nervous systems. Significant efforts have been devoted to developing therapeutic delivery systems that enable control of neurotrophin dosage in the brain. Here, we suggest that nanoparticulate carriers favoring targeted delivery in specific brain areas and minimizing biodistribution to the systemic circulation should be developed toward clinical benefits of neuroregeneration. We also provide examples of improved targeted neurotrophin delivery to localized areas in the CNS. PMID:23891881

Angelova, Angelina; Angelov, Borislav; Drechsler, Markus; Lesieur, Sylviane

2013-12-01

297

EUV Dimmings: Formation Mechanisms and Associated Phenomena  

NASA Astrophysics Data System (ADS)

Large-scale coronal EUV dimmings, developing on timescales of minutes to hours in association with a flare or filament eruption, are known to exhibit a high correlation with coronal mass ejections. While most observations indicate that the decrease in emission in a dimming is due, at least in part, to a density decrease, a complete understanding requires us to examine at least four mechanisms that have been observed to cause darkened regions in the corona: 1) mass loss, 2) cooling, 3) heating, and 4) absorption/obscuration. Recent advances in automatic detection, observations with improved cadence and resolution, multi-viewpoint imaging, and spectroscopic studies have continued to shed light on dimming formation, evolution, and recovery. However, there are still some outstanding questions, including 1) Why do some CMEs show dimming and some do not? 2) What determines the location of a dimming? 3) What determines the temporal evolution of a dimming? 4) How does the post-eruption dimming connect to the ICME? 5) What is the relationship between dimmings and other CME-associated phenomena? The talk will emphasize the different formation mechanisms of dimmings and their relationship to CMEs and CME-associated phenomena.

Thompson, B. J.; Mays, M. L.; West, M. J.

2012-12-01

298

Insulin Delivery System.  

National Technical Information Service (NTIS)

Aspects of the disclosure generally relate to insulin delivery systems and compositions having a insulin secreting .beta. cell line or insulin secreting recombinant non-.beta. cells sequestered in a glucose-responsive material. The disclosed insulin deliv...

A. Sambanis S. Y. Cheng

2005-01-01

299

Implantable Insulin Delivery System.  

National Technical Information Service (NTIS)

An insulin delivery system suitable for experimental implants and external use has been developed to study glucose control for diabetics. The programmable system developed at Sandia National Laboratories, in conjunction with the University of New Mexico S...

J. T. Love J. I. Gaona

1981-01-01

300

Project Delivery Methods.  

ERIC Educational Resources Information Center

Describes project delivery methods that are replacing the traditional Design/Bid/Build linear approach to the management, design, and construction of new facilities. These variations can enhance construction management and teamwork. (SLD)

Dolan, Thomas G.

2003-01-01

301

Optically generated ultrasound for enhanced drug delivery  

DOEpatents

High frequency acoustic waves, analogous to ultrasound, can enhance the delivery of therapeutic compounds into cells. The compounds delivered may be chemotherapeutic drugs, antibiotics, photodynamic drugs or gene therapies. The therapeutic compounds are administered systemically, or preferably locally to the targeted site. Local delivery can be accomplished through a needle, cannula, or through a variety of vascular catheters, depending on the location of routes of access. To enhance the systemic or local delivery of the therapeutic compounds, high frequency acoustic waves are generated locally near the target site, and preferably near the site of compound administration. The acoustic waves are produced via laser radiation interaction with an absorbing media and can be produced via thermoelastic expansion, thermodynamic vaporization, material ablation, or plasma formation. Acoustic waves have the effect of temporarily permeabilizing the membranes of local cells, increasing the diffusion of the therapeutic compound into the cells, allowing for decreased total body dosages, decreased side effects, and enabling new therapies.

Visuri, Steven R. (Livermore, CA); Campbell, Heather L. (Baltimore, MD); Da Silva, Luiz (Danville, CA)

2002-01-01

302

EUTOX CME course: Progression in CKD and management of the risk factors in dialysis patients (Meeting Report).  

PubMed

(Full text is available at http://www.manu.edu.mk/prilozi). On September 8, 1991, Macedonian citizens voted unanimously to have an independent state and to separate from Yugoslavia. This year, on September 8, we celebrated 20 years of independent Republic of Macedonia. The Macedonian Academy of Sciences and Arts, the Macedonian Society of Nephrology, Dialysis, Transplantation and Artificial Organs (MSNDTAO) and the EUTOX group as an endorsed group at the European Renal Association on October 22, 2011 organized a one-day scientific meeting (as a continuous medical education - CME course) on the topic of Progression in CKD and Management of the Risk Factors in Dialysis Patients. The meeting was held in the Macedonian Academy of Sciences and Arts. The speakers at the meeting and the titles of their presentations were: Momir Polenakovic, Member of the Macedonian Academy of Sciences and Arts, Honorary President of MSNDTAO: Nephrology in the 20 years of the independent Republic of Macedonia, Harald MISCHAK, Professor at the University of Glasgow, proteomics research within the British Heart Foundation Glasgow Cardiovascular Research Centre, Chief Scientific Officer (CSO) of mosaiques diagnostics and therapeutics AG, Professor in the Department of Nephrology at the Medical School of Hannover, Germany: Do we have markers on CKD progression and possibilities on mass screening? Goce SPASOVSKI, Professor, Department of Nephrology, Medical Faculty, Ss. Cyril and Methodius University, Skopje, R. Macedonia, President of the MSNDTAO, Chairmen of the ERA-EDTA CME Committee: Ca and P in the progression of CKD, Raymond VANHOLDER, Professor of Medicine at the University of Ghent, Belgium, Head of the Nephrology Division of the Ghent University Hospital, Ghent, Belgium, Past President of ESAO, President of ERA-EDTA: Can we prevent CKD progression by various adsorbing methods? Andrzej WIECEK, Professor, Silesian Medical Academy, Director, Department of Nephrology, Katowice, Poland: Anaemia as a cause of CKD progression, Alessandra PERNA, Professor, Second University of Naples, First Division of Nephrology - Faculty of Medicine, Naples, Italy: The role of low protein diet in the progression of CKD, Philippe BRUNET, Professor, University Aix - Marseille and INSERM 608 Nephrology - Hospital Conception, Marseille, France: Vascular dysfunction in dialysis patients, Angel ARGILÉS, Professor, Research Director of CNRS RD - Nephrology, Montpellier, France: Vascular calcification as a risk factor in dialysis patients, Ziad A. MASSY, Professor, MD, PhD, Divisions of Clinical Pharmacology and Nephrology INSERM ERI-12, University of Picardie and Amiens University Hospital Avenue Rene Laennec, France: Vascular calcification management in CKD patients, Juan Mariano RODRIGUEZ-PORTILLO, Professor, University Hospital Reina Sofia, Research Unit, Cordoba, Spain: FGF23 and Klotho. 70 participants from the Republic of Macedonia and neighbouring countries attended the meeting. The lectures were interesting and were followed by lively discussion among the participants. At the end it was concluded that chronic kidney diseases and chronic kidney insufficiency are problems in the whole world as well as in the Republic of Macedonia; early diagnosis and prevention of kidney diseases are necessary, as well as a stimulation of scientific research in nephrology. PMID:22286636

Polenakovic, M; Spasovski, G

2011-12-01

303

Analysis of EIT/LASCO Observations Using Available MHD Models: Investigation of CME Initiation Propagation and Geoeffectiveness  

NASA Technical Reports Server (NTRS)

The Sun's activity drives the variability of geospace (i.e., near-earth environment). Observations show that the ejection of plasma from the sun, called coronal mass ejections (CMEs), are the major cause of geomagnetic storms. This global-scale solar dynamical feature of coronal mass ejection was discovered almost three decades ago by the use of space-borne coronagraphs (OSO-7, Skylab/ATM and P78-1). Significant progress has been made in understanding the physical nature of the CMEs. Observations show that these global-scale CMEs have size in the order of a solar radius (approximately 6.7 x 10(exp 5) km) near the sun, and each event involves a mass of about 10(exp 15) g and an energy comparable to that of a large flare on the order of 10(exp 32) ergs. The radial propagation speeds of CMEs have a wide range from tens to thousands of kilometers per second. Thus, the transit time to near earth's environment [i.e., 1 AU (astronomical unit)] can be as fast as 40 hours to 100 hours. The typical transit time for geoeffective events is approximately 60-80 h. This paper consists of two parts: 1) A summary of the observed CMEs from Skylab to the present SOHO will be presented. Special attention will be made to SOHO/ LASCO/ EIT observations and their characteristics leading to a geoeffectiv a CME 2) The chronological development of theory and models to interpret the physical nature of this fascinating phenomenon will be reviewed. Finally, an example will be presented to illustrate the geoeffectiveness of the CMEs by using both observation and model.

Wu, S. T.

2001-01-01

304

Reactivity of Zirconocene Azametallacyclobutenes: Insertion of Aldehydes, Carbon Monoxide, and Formation of alpha,beta-Unsaturated Imines. Formation and Trapping of [Cp(2)Zr=O] in a [4 + 2] Retrocycloaddition(1).  

PubMed

Azametallacyclobutene Cp(2)ZrN-t-BuCEt=CEt (1) underwent an insertion reaction with CO to form the acyl complex 2 (Cp(2)Zr(N-t-BuCEtCEtCO), 67% yield). The addition of acetone to azametallacyclobutene 3 (Cp(2)Zr(NArCMeCPh), Ar = 2,6-dimethylphenyl) yielded the N-bonded enamine and O-bonded enolate complex of zirconocene 4 (Cp(2)Zr(NArCMeCPhH)(OCMeCH(2)), 76% yield). The addition of aldehydes RCOH to metallacycle 3 resulted in the insertion of the aldehyde into the Zr-C bond to form complexes Cp(2)Zr(NArCMeCPhCRHO) (8a) and Cp(2)Zr(NArCMeCPhC(i-Pr)HO (9) in 85% (R = Ph) and 73% yields, respectively. Similarly, treatment of metallacycle 10 (Cp(2)Zr(NArCEtCEt)) with benzaldehyde yielded the insertion product 11 (Cp(2)Zr(NArCEtCEtCPhHO)) in 56% isolated yield. The structure of complex 11 was confirmed by an X-ray crystallographic study. Heating the insertion products 8a and 9 led to elimination of the alpha,beta-unsaturated imines 13 and 14a (ArN=CMeCPh=CRH) in 53% and 72% yields, respectively, and the formation of oxozirconocene oligomer (Cp(2)ZrO)(n)(). The oxozirconocene monomer was trapped by dimethylzirconocene, preventing the formation of oligomer and resulting in the isolation of product 15. A kinetic study of this retrocycloaddition produced the following activation parameters: DeltaH() = 26.5 kcal/mol, DeltaS() = 3.48 eu. A Hammett sigma/rho study showed that electron-donating groups alpha to the metallacycle oxygen accelerate the retrocycloaddition (rho = -0.8). PMID:11667377

Hanna, Tracy A.; Baranger, Anne M.; Bergman, Robert G.

1996-07-12

305

Community Digital Library Requirements for the Southern California Earthquake Center Community Modeling Environment (SCEC/CME)  

NASA Astrophysics Data System (ADS)

A community digital library provides support for ingestion, organization, description, preservation, and access of digital entities. The technologies that traditionally provide these capabilities are digital libraries (ingestion, organization, description), persistent archives (preservation) and data grids (access). We present a design for the SCEC community digital library that incorporates aspects of all three systems. Multiple groups have created integrated environments that sustain large-scale scientific data collections. By examining these projects, the following stages of implementation can be identified: \\begin{itemize} Definition of semantic terms to associate with relevant information. This includes definition of uniform content descriptors to describe physical quantities relevant to the scientific discipline, and creation of concept spaces to define how the uniform content descriptors are logically related. Organization of digital entities into logical collections that make it simple to browse and manage related material. Definition of services that are used to access and manipulate material in the collection. Creation of a preservation environment for the long-term management of the collection. Each community is faced with heterogeneity that is introduced when data is distributed across multiple sites, or when multiple sets of collection semantics are used, and or when multiple scientific sub-disciplines are federated. We will present the relevant standards that simplify the implementation of the SCEC community library, the resource requirements for different types of data sets that drive the implementation, and the digital library processes that the SCEC community library will support. The SCEC community library can be viewed as the set of processing steps that are required to build the appropriate SCEC reference data sets (SCEC approved encoding format, SCEC approved descriptive metadata, SCEC approved collection organization, and SCEC managed storage location). Each digital entity that is ingested into the SCEC community library is processed and validated for conformance to SCEC standards. These steps generate provenance, descriptive, administrative, structural, and behavioral metadata. Using data grid technology, the descriptive metadata can be registered onto a logical name space that is controlled and managed by the SCEC digital library. A version of the SCEC community digital library is being implemented in the Storage Resource Broker. The SRB system provides almost all the features enumerated above. The peer-to-peer federation of metadata catalogs is planned for release in September, 2003. The SRB system is in production use in multiple projects, from high-energy physics, to astronomy, to earth systems science, to bio-informatics. The SCEC community library will be based on the definition of standard metadata attributes, the creation of logical collections within the SRB, the creation of access services, and the demonstration of a preservation environment. The use of the SRB for the SCEC digital library will sustain the expected collection size and collection capabilities.

Moore, R.; Faerman, M.; Minster, J.; Day, S. M.; Ely, G.

2003-12-01

306

Formation of Opposite-Sign Magnetic Helicity by an Erupting Filament in a Coronal Mass Ejection  

NASA Astrophysics Data System (ADS)

It is unclear whether it is possible for magnetic helical fields of opposite signs to co-exist in a coronal mass ejection (CME). During filament eruption with high-cadence observations for the initial stage, evidence is found for the formation of right-handed helical fields in a rising dextral filament that is embedded in a CME with helical fields in a left-handed sense. The data include Mees multi-off-band H? observations with 16s cadence and TRACE 1600Å observations of 2s cadence. The filament material is ejected outward and is associated with the expanding CME, suggesting that both of the opposite-sign helical fields are injected into interplanetary space. In this paper, we consider the key observational features, including the formation of a coil-like structure (due to barb reconnections) and the alignment of reconnected field lines with the primary axis of the filament. It is found that they are consistent with the predicted changes during filament eruption by the filament model of Martin and McAllister. However, our results do not reject the filament model of Rust and Kumar. Moreover, a model that reconciles both of them seems to be more convenient for understanding the complicated observations. Therefore, the formation of opposite-sign helicity in an eruptive flux rope should be common for such types of filament eruptions.

Liu, Yu; Kurokawa, Hiroki

2004-06-01

307

Genetic-Biochemical Analysis and Distribution of the Ambler Class A ?-Lactamase CME-2, Responsible for Extended-Spectrum Cephalosporin Resistance in Chryseobacterium (Flavobacterium) meningosepticum  

PubMed Central

In vitro synergy between extended-spectrum cephalosporins and either clavulanic acid or cefoxitin was found for Chryseobacterium meningosepticum isolates during a double-disk assay on an agar plate. An extended-spectrum ?-lactamase (ESBL) gene from a C. meningosepticum clinical isolate was cloned and expressed in Escherichia coli DH10B. Its protein conferred resistance to most ?-lactams including extended-spectrum cephalosporins but not to cephamycins or to imipenem. Its activity was strongly inhibited by clavulanic acid, sulbactam, and tazobactam, as well as by cephamycins and imipenem. Sequence analysis of the cloned DNA fragment revealed an open reading frame (ORF) of 891 bp with a G+C content of 33.9%, which lies close to the expected range of G+C contents of members of the Chryseobacterium genus. The ORF encoded a precursor protein of 297 amino acids, giving a mature protein with a molecular mass of 31 kDa and a pI value of 9.2 in E. coli. This gene was very likely chromosomally located. Amino acid sequence comparison showed that this ?-lactamase, named CME-2 (C. meningosepticum ESBL), is a novel ESBL of the Ambler class A group (Bush functional group 2be), being weakly related to other class A ?-lactamases. It shares only 39 and 35% identities with the ESBLs VEB-1 from E. coli MG-1 and CBL-A from Bacteroides uniformis, respectively. The distribution of blaCME-2 among unrelated C. meningosepticum species isolates showed that blaCME-2-like genes were found in the C. meningosepticum strains studied but were absent from strains of other C. meningosepticum-related species. Each C. meningosepticum strain produced at least two ?-lactamases, with one of them being a noninducible serine ESBL with variable pIs ranging from 7.0 to 8.5.

Bellais, Samuel; Poirel, Laurent; Naas, Thierry; Girlich, Delphine; Nordmann, Patrice

2000-01-01

308

CME Expansion as the Driver of Metric Type II Shock Emission as Revealed by Self-consistent Analysis of High-Cadence EUV Images and Radio Spectrograms  

NASA Astrophysics Data System (ADS)

On 13 June 2010, an eruptive event occurred near the solar limb. It included a small filament eruption and the onset of a relatively narrow coronal mass ejection (CME) surrounded by an extreme ultraviolet (EUV) wave front recorded by the Solar Dynamics Observatory's (SDO) Atmospheric Imaging Assembly (AIA) at high cadence. The ejection was accompanied by a GOES M1.0 soft X-ray flare and a Type-II radio burst; high-resolution dynamic spectra of the latter were obtained by the Appareil de Routine pour le Traitement et l'Enregistrement Magnetique de l'Information Spectral (ARTEMIS IV) radio spectrograph. The combined observations enabled a study of the evolution of the ejecta and the EUV wave front and its relationship with the coronal shock manifesting itself as metric Type-II burst. By introducing a novel technique, which deduces a proxy of the EUV compression ratio from AIA imaging data and compares it with the compression ratio deduced from the band-split of the Type-II metric radio burst, we are able to infer the potential source locations of the radio emission of the shock on that AIA images. Our results indicate that the expansion of the CME ejecta is the source for both EUV and radio shock emissions. Early in the CME expansion phase, the Type-II burst seems to originate in the sheath region between the EUV bubble and the EUV shock front in both radial and lateral directions. This suggests that both the nose and the flanks of the expanding bubble could have driven the shock.

Kouloumvakos, A.; Patsourakos, S.; Hillaris, A.; Vourlidas, A.; Preka-Papadema, P.; Moussas, X.; Caroubalos, C.; Tsitsipis, P.; Kontogeorgos, A.

2014-06-01

309

Security methods for MP3 music delivery  

Microsoft Academic Search

The impetus for the work presented in this paper arose from the need to enable Internet-based secure audio delivery and protection of digitized music against illegal distribution. The approach described, provides protection for the widely accepted MPEG-1 Layer-3 audio encoding format, although it can easily be applied to any other perceptual audio coding (PAC) standard. During the process of MP3

Niels J. Thorwirth; P. Horvatic; Rudiger Weis; Jian Zhao

2000-01-01

310

Changes in Altitude Cause Unintended Insulin Delivery From Insulin Pumps  

PubMed Central

OBJECTIVE Children and adults with type 1 diabetes who receive insulin pump therapy have reported hypoglycemia during air travel. We studied the effects of atmospheric pressure on insulin pump delivery. RESEARCH DESIGN AND METHODS Ten insulin pumps were connected to capillary tubes. The effects of changes in ambient pressure on insulin delivery, bubble formation, bubble size, and cartridge plunger movement were analyzed. RESULTS During a flight (200 mmHg pressure decrease), excess insulin delivery of 0.623% of the cartridge volume occurred (P < 0.001, Student t test). In hypobaric chamber studies, bubbles developed in the insulin when the pressure decreased and displaced the insulin out of the cartridge. Pre-existing bubbles changed in size consistent with Boyle law. Cartridge plunger movement did not occur in normal flight conditions but did occur when catastrophic plane depressurization was mimicked. CONCLUSIONS Atmospheric pressure reduction causes predictable, unintended insulin delivery in pumps by bubble formation and expansion of existing bubbles.

King, Bruce R.; Goss, Peter W.; Paterson, Megan A.; Crock, Patricia A.; Anderson, Donald G.

2011-01-01

311

Cement composite delivery system.  

PubMed

Several new and innovative techniques have recently been introduced that purport to increase the strength of polymethyl methacrylate bone cement. One of these concepts is the use of carbon and polymer fibers to form a cement composite. Bone cement composites usually 1% fiber, are very difficult to use clinically. The composite is very sticky and viscous, which precludes effective hand packing or the use of conventional delivery systems. A new delivery system for very viscous materials is presented and examples of in vitro application are shown. PMID:3453485

Convery, F R; Devine, S D; Hollis, J M; Woo, S L

1986-09-01

312

Systems and Components Fuel Delivery System, Water Delivery System, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Systems and Components - Fuel Delivery System, Water Delivery System, Derrick Crane System, and Crane System Details - Marshall Space Flight Center, F-1 Engine Static Test Stand, On Route 565 between Huntsville and Decatur , Huntsville, Madison County, AL

313

Microemulsion-based media as novel drug delivery systems.  

PubMed

Microemulsions are clear, stable, isotropic mixtures of oil, water and surfactant, frequently in combination with a cosurfactant. These systems are currently of interest to the pharmaceutical scientist because of their considerable potential to act as drug delivery vehicles by incorporating a wide range of drug molecules. In order to appreciate the potential of microemulsions as delivery vehicles, this review gives an overview of the formation and phase behaviour and characterization of microemulsions. The use of microemulsions and closely related microemulsion-based systems as drug delivery vehicles is reviewed, with particular emphasis being placed on recent developments and future directions. PMID:11104900

Lawrence, M J; Rees, G D

2000-12-01

314

Italy. [CME Country Reports].  

ERIC Educational Resources Information Center

Ever since 1946, increased emigration in Italy has been paralleled by a slow but steady increase in educational activity. In 1971, Law No. 153 was adopted which provides for special educational arrangements to be made for migrant workers and their spouses adopted by the Italian Government are based on the need for Italian children to: (1) be…

Council of Europe, Strasbourg (France). Documentation Center for Education in Europe.

315

Luxembourg. [CME Country Reports].  

ERIC Educational Resources Information Center

The Luxembourg policy for providing education and training for migrant workers and their children is to offer the same opportunities as for nationals. The main difficulties so far are providing for children aged 9 and over and teaching students, especially those with a Latin language as their mother tongue, the languages used in the host schools…

Council of Europe, Strasbourg (France). Documentation Center for Education in Europe.

316

Implantable insulin delivery system  

SciTech Connect

An insulin delivery system suitable for experimental implants and external use has been developed to study glucose control for diabetics. The programmable system developed at Sandia National Laboratories, in conjunction with the University of New Mexico School of Medicine, employs miniature electronics and mechanical technologies developed for use in other Department of Energy programs.

Love, J.T.; Gaona, J.I. Jr.

1981-01-01

317

Knowledge Delivery Research.  

National Technical Information Service (NTIS)

The goal of knowledge delivery research is to create a technology of authorship by computer. Existing technology is all in the laboratory stage, and is limited to very small, rigidly constrained texts. This research project has focused on two kinds of dev...

W. C. Mann

1986-01-01

318

Microfabricated drug delivery devices  

Microsoft Academic Search

We review newest developments in the design and fabrication of drug delivery devices based on micropatterned structures. Electronic devices have now reached a stage of dimensions comparable to those of biological macromolecules. This raises exciting possibilities for combining microelectronics and biotechnology to develop new technologies with unprecedented power and versatility. While molecular electronics use the unique self-assembly, switching and dynamic

J. Zachary Hilt; Nicholas A. Peppas

2005-01-01

319

GENE DELIVERY TO BONE  

PubMed Central

Gene delivery to bone is useful both as an experimental tool and as a potential therapeutic strategy. Among its advantages over protein delivery are the potential for directed, sustained and regulated expression of authentically processed, nascent proteins. Although no clinical trials have been initiated, there is a substantial pre-clinical literature documenting the successful transfer of genes to bone, and their intraosseous expression. Recombinant vectors derived from adenovirus, retrovirus and lentivirus, as well as non-viral vectors, have been used for this purpose. Both ex vivo and in vivo strategies, including gene-activated matrices, have been explored. Ex vivo delivery has often employed mesenchymal stem cells (MSCs), partly because of their ability to differentiate into osteoblasts. MSCs also have the potential to home to bone after systemic administration, which could serve as a useful way to deliver transgenes in a disseminated fashion for the treatment of diseases affecting the whole skeleton, such as osteoporosis or osteogenesis imperfecta. Local delivery of osteogenic transgenes, particularly those encoding bone morphogenetic proteins, has shown great promise in a number of applications where it is necessary to regenerate bone. These include healing large segmental defects in long bones and the cranium, as well as spinal fusion and treating avascular necrosis.

Evans, C. H.

2012-01-01

320

Document Delivery Expert.  

ERIC Educational Resources Information Center

Describes the design of an expert system developed using VP-Expert for document delivery decision making in a law library. Presents methods used in knowledge acquisition and knowledge representation after a brief review of the literature on expert system use in libraries. An appendix includes the rules of the expert system. (Author/AEF)

Abate, Anne K.

1995-01-01

321

APOD: Anonymous Physical Object Delivery  

Microsoft Academic Search

Delivery of products bought online can violate consumers' privacy, although not in a straightforward way. In particular, delivery companies that have contracted with a website know the company selling the product, as well as the name and address of the online customer. To make matters worse, if the same delivery company has contracted with many websites, aggregated information per address

Elli Androulaki; Steven M. Bellovin

2009-01-01

322

Drug delivery to damaged brain  

Microsoft Academic Search

Drug delivery to the brain poses unique challenges. Specialized anatomic and physiological features of the cerebrovasculature and cerebral tissue fluids result in barriers which significantly restrict delivery of a wide range of possible therapeutic agents. In addition to these normal restrictions to brain drug delivery, pathophysiological features and sequelae of acute brain injury will also impact upon the efficiency of

Eng H. Lo; Aneesh B. Singhal; Vladimir P. Torchilin; N. Joan Abbott

2001-01-01

323

Peptide and protein delivery using new drug delivery systems.  

PubMed

Pharmaceutical and biotechnological research sorts protein drug delivery systems by importance based on their various therapeutic applications. The effective and potent action of the proteins/peptides makes them the drugs of choice for the treatment of numerous diseases. Major research issues in protein delivery include the stabilization of proteins in delivery devices and the design of appropriate target-specific protein carriers. Many efforts have been made for effective delivery of proteins/peptidal drugs through various routes of administrations for successful therapeutic effects. Nanoparticles made of biodegradable polymers such as poly lactic acid, polycaprolactone, poly(lactic-co-glycolic acid), the poly(fumaric-co-sebacic) anhydride chitosan, and modified chitosan, as well as solid lipids, have shown great potential in the delivery of proteins/peptidal drugs. Moreover, scientists also have used liposomes, PEGylated liposomes, niosomes, and aquasomes, among others, for peptidal drug delivery. They also have developed hydrogels and transdermal drug delivery systems for peptidal drug delivery. A receptor-mediated delivery system is another attractive strategy to overcome the limitation in drug absorption that enables the transcytosis of the protein across the epithelial barrier. Modification such as PEGnology is applied to various proteins and peptides of the desired protein and peptides also increases the circulating life, solubility and stability, pharmacokinetic properties, and antigenicity of protein. This review focuses on various approaches for effective protein/peptidal drug delivery, with special emphasis on insulin delivery. PMID:23662604

Jain, Ashish; Jain, Aviral; Gulbake, Arvind; Shilpi, Satish; Hurkat, Pooja; Jain, Sanjay K

2013-01-01

324

Transdermal drug delivery.  

PubMed

Transdermal drug delivery is a validated technology contributing significantly to global pharmaceutical care. Since 1980, impressive growth in this field has been observed with many commercial successes; importantly, a new chemical entity was recently developed and approved for transdermal administration without having first been given as an injectable or oral dosage form. The progress achieved has been based on the clearer understanding of skin barrier function, and of the physicochemical, pharmacokinetic and physiological factors which underpin the feasibility of transdermal administration. Novel, non-invasive approaches to enhance and control drug transport across the skin are under intensive investigation, and some technologies, e.g. iontophoresis, have reached true maturity. The "local", subcutaneous delivery of drugs (for example, to underlying muscle and other tissues) is gaining increasing acceptance, and new opportunities in this under-subscribed area may be envisaged. PMID:20217537

Guy, Richard H

2010-01-01

325

Fuel delivery system  

SciTech Connect

A engine fuel delivery system for vehicles under test, which effectively limits the quantity of fuel under pressurization at any given time during a test sequence of the vehicle`s engine. The system thus effectively reduces the magnitude of an explosion which may be caused by pressurization of fuel, and thus the scale of any damage, associated with any inadvertent detonation of pressurized engine fuel.

Escobar, M.J.

1996-12-31

326

Convection-Enhanced Delivery  

Microsoft Academic Search

Drug delivery is thought to be one of the limitations of therapies for brain tumors. Systemic administration of potential\\u000a drugs requires high dosages to achieve therapeutic levels within the tumor itself and in the surrounding brain tissue because\\u000a of the limited\\/selective flow across the blood-brain barrier. In spite of high systemic dosages, however, some of these drugs\\u000a not only fail

Andrew A. Kanner

327

Nanostructured materials for applications in drug delivery and tissue engineering*  

PubMed Central

Research in the areas of drug delivery and tissue engineering has witnessed tremendous progress in recent years due to their unlimited potential to improve human health. Meanwhile, the development of nanotechnology provides opportunities to characterize, manipulate and organize matter systematically at the nanometer scale. Biomaterials with nano-scale organizations have been used as controlled release reservoirs for drug delivery and artificial matrices for tissue engineering. Drug-delivery systems can be synthesized with controlled composition, shape, size and morphology. Their surface properties can be manipulated to increase solubility, immunocompatibility and cellular uptake. The limitations of current drug delivery systems include suboptimal bioavailability, limited effective targeting and potential cytotoxicity. Promising and versatile nano-scale drug-delivery systems include nanoparticles, nanocapsules, nanotubes, nanogels and dendrimers. They can be used to deliver both small-molecule drugs and various classes of biomacromolecules, such as peptides, proteins, plasmid DNA and synthetic oligodeoxynucleotides. Whereas traditional tissue-engineering scaffolds were based on hydrolytically degradable macroporous materials, current approaches emphasize the control over cell behaviors and tissue formation by nano-scale topography that closely mimics the natural extracellular matrix (ECM). The understanding that the natural ECM is a multifunctional nanocomposite motivated researchers to develop nanofibrous scaffolds through electrospinning or self-assembly. Nanocomposites containing nanocrystals have been shown to elicit active bone growth. Drug delivery and tissue engineering are closely related fields. In fact, tissue engineering can be viewed as a special case of drug delivery where the goal is to accomplish controlled delivery of mammalian cells. Controlled release of therapeutic factors in turn will enhance the efficacy of tissue engineering. From a materials point of view, both the drug-delivery vehicles and tissue-engineering scaffolds need to be biocompatible and biodegradable. The biological functions of encapsulated drugs and cells can be dramatically enhanced by designing biomaterials with controlled organizations at the nanometer scale. This review summarizes the most recent development in utilizing nanostructured materials for applications in drug delivery and tissue engineering.

GOLDBERG, MICHAEL; LANGER, ROBERT; JIA, XINQIAO

2010-01-01

328

Structures of AcrR and CmeR: insight into the mechanisms of transcriptional repression and multi-drug recognition in the TetR family of regulators.  

PubMed

The transcriptional regulators of the TetR family act as chemical sensors to monitor the cellular environment in many bacterial species. To perform this function, members of the TetR family harbor a diverse ligand-binding domain capable of recognizing the same series of compounds as the transporters they regulate. Many of the regulators can be induced by a wide array of structurally unrelated compounds. Binding of these structurally unrelated ligands to the regulator results in a conformational change that is transmitted to the DNA-binding region, causing the repressor to lose its DNA-binding capacity and allowing for the initiation of transcription. The multi-drug binding proteins AcrR of Escherichia coli and CmeR from Campylobacter jejuni are members of the TetR family of transcriptional repressors that regulate the expression of the multidrug resistant efflux pumps AcrAB and CmeABC, respectively. To gain insights into the mechanisms of transcriptional regulation and how multiple ligands induce the same physiological response, we determined the crystal structures of the AcrR and CmeR regulatory proteins. In this review, we will summarize the new findings with AcrR and CmeR, and discuss the novel features of these two proteins in comparison with other regulators in the TetR family. PMID:19130905

Routh, Mathew D; Su, Chih-Chia; Zhang, Qijing; Yu, Edward W

2009-05-01

329

Local magnetism in the molecule-based metamagnet [Ru2(O2CMe)4]3[Cr(CN)6] probed with implanted muons  

SciTech Connect

We present a muon-spin relaxation study of local magnetism in the molecule-based metamagnet [Ru2(O2CMe)4]3[Cr(CN)6]. We observe magnetic order with TN = 33 K, although above 25 K the sublattice spins become less rigid and a degree of static magnetic disorder is observed. The comparison of measurements in applied magnetic field with simulations allows us to understand the origin of the muon response across the metamagnetic transition and to map out the phase diagram of the material. Applied hydrostatic pressures of up to 6 kbar lead to an increase in the local magnetic field along with a complex change in the internal magnetic field distribution.

Lancaster, T. [University of Oxford; Pratt, F. L. [ISIS Facility, Rutherford Appleton Laboratory; Blundell, S. J. [University of Oxford; Steele, Andrew J. [University of Oxford; Baker, Peter J. [ISIS Facility, Rutherford Appleton Laboratory; Wright, Jack D. [University of Oxford; Fishman, Randy Scott [ORNL; Miller, Joel S. [University of Utah

2011-01-01

330

DELIVERY OF THERAPEUTIC PROTEINS  

PubMed Central

The safety and efficacy of protein therapeutics are limited by three interrelated pharmaceutical issues, in vitro and in vivo instability, immunogenicity and shorter half-lives. Novel drug modifications for overcoming these issues are under investigation and include covalent attachment of poly(ethylene glycol) (PEG), polysialic acid, or glycolic acid, as well as developing new formulations containing nanoparticulate or colloidal systems (e.g. liposomes, polymeric microspheres, polymeric nanoparticles). Such strategies have the potential to develop as next generation protein therapeutics. This review includes a general discussion on these delivery approaches.

Pisal, Dipak S.; Kosloski, Matthew P.; Balu-Iyer, Sathy V.

2009-01-01

331

Ultrasound-mediated drug delivery  

Microsoft Academic Search

Although ultrasound-based drug delivery has only seen limited clinical use for transdermal drug delivery, there has been considerable momentum in research aimed at using ultrasound for a wide variety of medical applications. Ultrasound-mediated gene therapy using sonoporation and targeted delivery has progressed from in vitro proof-of-concept studies to produce biological effects in angiogenesis and diabetes studies. These techniques have also

ERIC C. PUA; Pei Zhong

2009-01-01

332

Direct Evidence for a Fast Coronal Mass Ejection Driven by the Prior Formation and Subsequent Destabilization of a Magnetic Flux Rope  

NASA Astrophysics Data System (ADS)

Magnetic flux ropes play a central role in the physics of coronal mass ejections (CMEs). Although a flux-rope topology is inferred for the majority of coronagraphic observations of CMEs, a heated debate rages on whether the flux ropes pre-exist or whether they are formed on-the-fly during the eruption. Here, we present a detailed analysis of extreme-ultraviolet observations of the formation of a flux rope during a confined flare followed about 7 hr later by the ejection of the flux rope and an eruptive flare. The two flares occurred during 2012 July 18 and 19. The second event unleashed a fast (>1000 km s-1) CME. We present the first direct evidence of a fast CME driven by the prior formation and destabilization of a coronal magnetic flux rope formed during the confined flare on July 18.

Patsourakos, S.; Vourlidas, A.; Stenborg, G.

2013-02-01

333

MRI in ocular drug delivery  

PubMed Central

Conventional pharmacokinetic methods for studying ocular drug delivery are invasive and cannot be conveniently applied to humans. The advancement of MRI technology has provided new opportunities in ocular drug-delivery research. MRI provides a means to non-invasively and continuously monitor ocular drug-delivery systems with a contrast agent or compound labeled with a contrast agent. It is a useful technique in pharmacokinetic studies, evaluation of drug-delivery methods, and drug-delivery device testing. Although the current status of the technology presents some major challenges to pharmaceutical research using MRI, it has a lot of potential. In the past decade, MRI has been used to examine ocular drug delivery via the subconjunctival route, intravitreal injection, intrascleral injection to the suprachoroidal space, episcleral and intravitreal implants, periocular injections, and ocular iontophoresis. In this review, the advantages and limitations of MRI in the study of ocular drug delivery are discussed. Different MR contrast agents and MRI techniques for ocular drug-delivery research are compared. Ocular drug-delivery studies using MRI are reviewed.

Li, S. Kevin; Lizak, Martin J.; Jeong, Eun-Kee

2008-01-01

334

Photomechanical drug delivery  

NASA Astrophysics Data System (ADS)

Photomechanical waves (PW) are generated by Q-switched or mode-locked lasers. Ablation is a reliable method for generating PWs with consistent characteristics. Depending on the laser wavelength and target material, PWs with different parameters can be generated which allows the investigation of PWs with cells and tissue. PWs have been shown to permeabilize the stratum corneum (SC) in vivo and facilitate the transport of drugs into the skin. Once a drug has diffused into the dermis it can enter the vasculature, thus producing a systemic effect. Fluorescence microscopy of biopsies show that 40-kDa molecules can be delivered to a depth of > 300 micrometers into the viable skin of rats. Many important drugs such as insulin, and erythropoietin are smaller or comparable in size, making the PWs attractive for transdermal drug delivery. There are three possible pathways through the SC: Transappendageal via hair follicles or other appendages, transcellular through the corneocytes, and intercellular via the extracellular matrix. The intracellular route appears to be the most likely pathway of drug delivery through the SC.

Doukas, Apostolos G.; Lee, Shun

2000-05-01

335

The split delivery vehicle routing problem with minimum delivery amounts  

Microsoft Academic Search

In the vehicle routing problem, a fleet of vehicles must service the demands of customers in a least-cost way. By allowing multiple vehicles to service the same customer (i.e., splitting deliveries), substantial savings in travel costs are possible. However, split deliveries are often an inconvenience to the customer who would prefer to have demand serviced in a single visit. We

Damon Gulczynski; Bruce Golden; Edward Wasil

2010-01-01

336

Coordination Compounds of Strontium. Syntheses, Characterizations, and Crystal Structures of [Sr(u-ONc)(2)(HONc(4))]2 and Sr(5)(u(4)-O)(u(3)-ONep)(4)(u-ONep)(4)(HONep)(solv)(4) (ONc=O(2)CCH(2)CMe(3));Nep=CH(2)CMe(3); solv=tetrahydrofuran or 1-methyl-imida  

SciTech Connect

The authors have synthesized and characterized two novel Sr compounds: [Sr({mu}-ONc){sub 2}(HONc){sub 4}]{sub 2} (1, ONc = O{sub 2}CCH{sub 2}CMe{sub 3}), and Sr{sub 5}({mu}{sub 4}-O)({mu}{sub 3}-ONep){sub 4}({mu}-ONep){sub 4}(HONep)(solv){sub 4} [ONep = OCH{sub 2}CMe{sub 3}, solv = tetrahydrofuran (THF), 2a; 1-methyl-imidazole (MeIm), (2b)], that demonstrate increased solubility in comparison to the commercially available Sr precursors. The two metal centers of 1 share 4 unidentate bridging {mu}-ONc ligands and complete their octahedral geometry through the coordination of 4 monodentate terminal HONc ligands. The structure arrangement of the central core of 2a and b are identical, wherein 4 octahedral Sr atoms are arranged in a square geometry around a {mu}{sub 4}-O ligand. An additional 7-coordinated Sr atom sits directly atop the {mu}{sub 4}-O to form a square base pyramidal arrangement of the Sr atoms but the apical Sr-O distance is too long to be considered a bond. In solution, compound 1 is disrupted forming a monomer but 2a and b retain their structures.

Boyle, Timothy J.; Tafoya, Cory J.; Scott, Brian L.; Ziller, Joseph W.

1999-07-21

337

Nanotechnology-based drug delivery systems  

Microsoft Academic Search

Nanoparticles hold tremendous potential as an effective drug delivery system. In this review we discussed recent developments in nanotechnology for drug delivery. To overcome the problems of gene and drug delivery, nanotechnology has gained interest in recent years. Nanosystems with different compositions and biological properties have been extensively investigated for drug and gene delivery applications. To achieve efficient drug delivery

Sarabjeet Singh Suri; Hicham Fenniri; Baljit Singh

2007-01-01

338

Challenges in media delivery systems and servers  

NASA Astrophysics Data System (ADS)

Although multimedia compression formats and protocols to stream such content have been around for a long time, there has been limited success in the adoption of open standards for streaming over IP (Internet Protocol) networks. The elements of such an end-to-end system will be introduced outlining the responsibilities of each element. The technical and financial challenges in building a viable multimedia streaming end-to-end system will be analyzed in detail in this paper outlining some solutions and areas for further research. Also, recent migration to IP in the backend video delivery network infrastructures have made it possible to use IP based media streaming solutions in non-IP last mile access networks like cable and wireless networks in addition to the DSL networks. The advantages of using IP streaming solutions in such networks will be outlined. However, there is a different set of challenges posed by such applications. The real time constraints are acute in each element of the media delivery end-to-end system. Meeting these real time constraints in general purpose non real time server systems is quite demanding. Quality of service, resource management, session management, fail-over, reliability, and cost are some important but challenging requirements in such systems. These will also be analyzed with suggested solutions. Content protection and rights management requirements are also very challenging for open standards based multimedia delivery systems. Interoperability unfortunately interferes with security in most of the current day systems. Some approaches to solve the interoperability problems will also be presented. The requirements, challenges, and possible solutions for delivering broadcast, on demand, and interactive video delivery applications for IP based media streaming systems will be analyzed in detail.

Swaminathan, Viswanathan

2005-03-01

339

Economical ground data delivery  

NASA Technical Reports Server (NTRS)

Data delivery in the Deep Space Network (DSN) involves transmission of a small amount of constant, high-priority traffic and a large amount of bursty, low priority data. The bursty traffic may be initially buffered and then metered back slowly as bandwidth becomes available. Today both types of data are transmitted over dedicated leased circuits. The authors investigated the potential of saving money by designing a hybrid communications architecture that uses leased circuits for high-priority network communications and dial-up circuits for low-priority traffic. Such an architecture may significantly reduce costs and provide an emergency backup. The architecture presented here may also be applied to any ground station-to-customer network within the range of a common carrier. The authors compare estimated costs for various scenarios and suggest security safeguards that should be considered.

Markley, Richard W.; Byrne, Russell H.; Bromberg, Daniel E.

1994-01-01

340

Secondary fuel delivery system  

DOEpatents

A secondary fuel delivery system for delivering a secondary stream of fuel and/or diluent to a secondary combustion zone located in the transition piece of a combustion engine, downstream of the engine primary combustion region is disclosed. The system includes a manifold formed integral to, and surrounding a portion of, the transition piece, a manifold inlet port, and a collection of injection nozzles. A flowsleeve augments fuel/diluent flow velocity and improves the system cooling effectiveness. Passive cooling elements, including effusion cooling holes located within the transition boundary and thermal-stress-dissipating gaps that resist thermal stress accumulation, provide supplemental heat dissipation in key areas. The system delivers a secondary fuel/diluent mixture to a secondary combustion zone located along the length of the transition piece, while reducing the impact of elevated vibration levels found within the transition piece and avoiding the heat dissipation difficulties often associated with traditional vibration reduction methods.

Parker, David M. (Oviedo, FL) [Oviedo, FL; Cai, Weidong (Oviedo, FL) [Oviedo, FL; Garan, Daniel W. (Orlando, FL) [Orlando, FL; Harris, Arthur J. (Orlando, FL) [Orlando, FL

2010-02-23

341

Post caesarean section delivery.  

PubMed

Recent clinical attention has focused upon the rising rate of caesarean sections being performed and whether patients with a previous caesarean section should be allowed a vaginal delivery. In this paper, the worldwide trend of caesarean section and the role of trial of scar following single and multiple caesarean surgery is reviewed. The role of oxytocin and regional epidural analgesia is evaluated as well as perinatal and maternal mortality. On the basis of the available data, there is no justification for the current clinical practice of almost 99% prevalence of elective repeat caesarean section in some hospitals in the North America. Oxytocin and epidural analgesia, when carefully monitored, are safe and reasonable in these patients. Watchful waiting has always been an essential virtue in obstetric management and should not be replaced by hopeful expectancy. This aspect of the art of obstetrics would appear to require rejuvenation if we are to stem the rising tide of caesarean sections. PMID:8288013

Bolaji, I I; Meehan, F P

1993-10-29

342

Bioresponsive matrices in drug delivery  

Microsoft Academic Search

For years, the field of drug delivery has focused on (1) controlling the release of a therapeutic and (2) targeting the therapeutic to a specific cell type. These research endeavors have concentrated mainly on the development of new degradable polymers and molecule-labeled drug delivery vehicles. Recent interest in biomaterials that respond to their environment have opened new methods to trigger

Jin-Oh You; Dariela Almeda; George JC Ye; Debra T Auguste

2010-01-01

343

Adhesion barriers at cesarean delivery: advertising compared with the evidence.  

PubMed

Cesarean delivery, the most common surgery performed in the United States, is complicated by adhesion formation in 24-73% of cases. Because adhesions have potential sequelae, different synthetic adhesion barriers are currently heavily marketed as a means of reducing adhesion formation resultant from cesarean delivery. However, their use for this purpose has been studied in only two small, nonblinded and nonrandomized trials, both of which were underpowered and subject to bias. Neither demonstrated improvement in meaningful clinical outcomes. In the only cost-effectiveness analysis of adhesion barriers to date, the use of synthetic adhesion barriers was cost-effective only when the subsequent rate of small bowel obstruction was at least 2.4%, a rate far higher than that associated with cesarean delivery. In fact, intra-abdominal adhesions from prior cesarean delivery rarely cause maternal harm and have not been demonstrated to adversely affect perinatal outcome. Based on our review of the available literature, we think the use of adhesion barriers at the time of cesarean delivery would be ill-advised at the present time. PMID:21691174

Albright, Catherine M; Rouse, Dwight J

2011-07-01

344

Novel Delivery Strategies for Glioblastoma  

PubMed Central

Brain tumors—particularly glioblastoma multiforme (GBM)—pose an important public health problem in the US. Despite surgical and medical advances, the prognosis for patients with malignant gliomas remains grim: current therapy for is insufficient with nearly universal recurrence. A major reason for this failure is the difficulty of delivering therapeutic agents to the brain: better delivery approaches are needed to improve treatment. In this article, we summarize recent progress in drug delivery to the brain, with an emphasis on convection-enhanced delivery of nanocarriers. We examine the potential of new delivery methods to permit novel drug- and gene-based therapies that target brain cancer stem cells (BCSCs) and discuss the use of nanomaterials for imaging of tumors and drug delivery.

Zhou, Jiangbing; Atsina, Kofi-Buaku; Himes, Benjamin T.; Strohbehn, Garth W.; Saltzman, W. Mark

2012-01-01

345

Hydrogels for Lentiviral Gene Delivery  

PubMed Central

Introduction Gene delivery from hydrogel biomaterials provides a fundamental tool for a variety of clinical applications including regenerative medicine, gene therapy for inherited disorders and drug delivery. The high water content and mild gelation conditions of hydrogels support their use for gene delivery by preserving activity of lentiviral vectors and acting to shield vectors from any host immune response. Areas Covered Strategies to control lentiviral entrapment within and retention/release from hydrogels are reviewed. We discuss the ability of hydrogel design parameters to control the transgene expression profile and the capacity of hydrogels to protect vectors from (and even modulate) the host immune response. Expert Opinion Delivery of genetic vectors from scaffolds provides a unique opportunity to capitalize on the potential synergy between the biomaterial design for cell processes and gene delivery. Hydrogel properties can be tuned to directly control the events that determine the tissue response to controlled gene delivery, which include the extent of cell infiltration, preservation of vector activity and vector retention. While some design parameters have been identified, numerous opportunities for investigation are available in order to develop a complete model relating the biomaterial properties and host response to gene delivery.

Seidlits, Stephanie K.; Gower, R. Michael; Shepard, Jaclyn A.; Shea, Lonnie D.

2013-01-01

346

Cell-Mediated Drugs Delivery  

PubMed Central

INTRODUCTION Drug targeting to sites of tissue injury, tumor or infection with limited toxicity is the goal for successful pharmaceutics. Immunocytes (including mononuclear phagocytes (dendritic cells, monocytes and macrophages), neutrophils, and lymphocytes) are highly mobile; they can migrate across impermeable barriers and release their drug cargo at sites of infection or tissue injury. Thus immune cells can be exploited as trojan horses for drug delivery. AREAS COVERED IN THIS REVIEW This paper reviews how immunocytes laden with drugs can cross the blood brain or blood tumor barriers, to facilitate treatments for infectious diseases, injury, cancer, or inflammatory diseases. The promises and perils of cell-mediated drug delivery are reviewed, with examples of how immunocytes can be harnessed to improve therapeutic end points. EXPERT OPINION Using cells as delivery vehicles enables targeted drug transport, and prolonged circulation times, along with reductions in cell and tissue toxicities. Such systems for drug carriage and targeted release represent a novel disease combating strategy being applied to a spectrum of human disorders. The design of nanocarriers for cell-mediated drug delivery may differ from those used for conventional drug delivery systems; nevertheless, engaging different defense mechanisms into drug delivery may open new perspectives for the active delivery of drugs.

Batrakova, Elena V.; Gendelman, Howard E.; Kabanov, Alexander V.

2011-01-01

347

Why new delivery systems?  

PubMed

Although anesthetists have accomplished a remarkable safety record with commercially available anesthetic machines, these results have been obtained in spite of machine design, which could best be described as a nonsystem. In cases involving severely compromised patients, surgical procedures that severely alter patient physiology, and untoward events during "routine" anesthesia, it is a tribute to the flexibility and resourcefulness of anesthetists that more incidents do not occur. Industry has long sought precision, reliability, automatic control, and human-factors engineering in nonmedical applications, such as aircraft cockpit design, word-processing stations, and manufacturing processes. The relentless accretion of more and more nonintegrated gadgets onto an antiquated technology has exceeded the boundaries of proper function. Neither the patient nor the anesthetist is being served well by failure to implement state-of-the-art technology in anesthesic delivery systems. Anesthesiologists and others who are vitally interested in the welfare of their patients must insist that development of radically new integrated modular systems proceed at full speed. Their checkbooks can speak as loudly as the facts; it is time the manufacturers are aware that deep concern will be translated into purchasing decisions. PMID:6692678

Calkins, J M

1984-01-01

348

DEtonation gas delivery unit  

SciTech Connect

The detonation gas for gas-detonatable blasting charges used in surface mining and the like is supplied by a portable self-contained delivery unit connected to the blasting charges by a network of small flexible tubing, which unit blends pressurized fuel and oxidizing gases from separate supply sources in predetermined proportions and regulates the separate flows of such gases in response to the backpressure imposed by the tubing network to maintain such proportions in the gas blend delivered to the tubing network. The separate gas flows are controlled by servo-actuated flow control valves actuated by a control gas pressure which is applied or released in response to such backpressure. Preferably, the control gas pressure is regulated by a pair of pilot valves, one normally open and the other normally closed, connected in parallel between the servo actuators of such flow control valves and the control gas source and the atmosphere, respectively, the state of the pilot valves being reversed in response to the occurrence of a backpressure exceeding a predetermined maximum to disconnect the control gas from and release the existing gas pressure on the flow control valve servo actuators. A preferred safety feature assures complete filling of the tubing network before the gas therein can be ignited to initiate detonation of the explosive charges.

Emmett, G. C.

1984-12-04

349

Delivery of bone morphogenetic protein-2 and substance P using graphene oxide for bone regeneration  

PubMed Central

In this study, we demonstrate that graphene oxide (GO) can be used for the delivery of bone morphogenetic protein-2 (BMP-2) and substance P (SP), and that this delivery promotes bone formation on titanium (Ti) implants that are coated with GO. GO coating on Ti substrate enabled a sustained release of BMP-2. BMP-2 delivery using GO-coated Ti exhibited a higher alkaline phosphatase activity in bone-forming cells in vitro compared with bare Ti. SP, which is known to recruit mesenchymal stem cells (MSCs), was co-delivered using Ti or GO-coated Ti to further promote bone formation. SP induced the migration of MSCs in vitro. The dual delivery of BMP-2 and SP using GO-coated Ti showed the greatest new bone formation on Ti implanted in the mouse calvaria compared with other groups. This approach may be useful to improve osteointegration of Ti in dental or orthopedic implants.

La, Wan-Geun; Jin, Min; Park, Saibom; Yoon, Hee-Hun; Jeong, Gun-Jae; Bhang, Suk Ho; Park, Hoyoung; Char, Kookheon; Kim, Byung-Soo

2014-01-01

350

Variable delivery, fixed displacement pump  

DOEpatents

A variable delivery, fixed displacement pump comprises a plurality of pistons reciprocated within corresponding cylinders in a cylinder block. The pistons are reciprocated by rotation of a fixed angle swash plate connected to the pistons. The pistons and cylinders cooperate to define a plurality of fluid compression chambers each have a delivery outlet. A vent port is provided from each fluid compression chamber to vent fluid therefrom during at least a portion of the reciprocal stroke of the piston. Each piston and cylinder combination cooperates to close the associated vent port during another portion of the reciprocal stroke so that fluid is then pumped through the associated delivery outlet. The delivery rate of the pump is varied by adjusting the axial position of the swash plate relative to the cylinder block, which varies the duration of the piston stroke during which the vent port is closed.

Sommars, Mark F. (Sparland, IL)

2001-01-01

351

Systematic Delivery of Career Information.  

ERIC Educational Resources Information Center

Briefly surveyed are information analyses, delivery devices, and user services--the three staff activities necessary for successful operation of a system for career information. Also discussed are the organizational and financial components that enable them to function. (AF)

McKinlay, Bruce

1979-01-01

352

Driving delivery vehicles with ultrasound ?  

PubMed Central

Therapeutic applications of ultrasound have been considered for over 40 years, with the mild hyperthermia and associated increases in perfusion produced by ultrasound harnessed in many of the earliest treatments. More recently, new mechanisms for ultrasound-based or ultrasound-enhanced therapies have been described, and there is now great momentum and enthusiasm for the clinical translation of these techniques. This dedicated issue of Advanced Drug Delivery Reviews, entitled “Ultrasound for Drug and Gene Delivery,” addresses the mechanisms by which ultrasound can enhance local drug and gene delivery and the applications that have been demonstrated at this time. In this commentary, the identified mechanisms, delivery vehicles, applications and current bottlenecks for translation of these techniques are summarized.

Ferrara, Katherine W.

2009-01-01

353

Drug delivery to the ear.  

PubMed

Drug delivery to the ear is used to treat conditions of the middle and inner ear such as acute and chronic otitis media, Ménière's disease, sensorineural hearing loss and tinnitus. Drugs used include antibiotics, antifungals, steroids, local anesthetics and neuroprotective agents. A literature review was conducted searching Medline (1966-2012), Embase (1988-2012), the Cochrane Library and Ovid (1966-2012), using search terms 'drug delivery', 'middle ear', 'inner ear' and 'transtympanic'. There are numerous methods of drug delivery to the middle ear, which can be categorized as topical, systemic (intravenous), transtympanic and via the Eustachian tube. Localized treatments to the ear have the advantages of targeted drug delivery allowing higher therapeutic doses and minimizing systemic side effects. The ideal scenario would be a carrier system that could cross the intact tympanic membrane loaded with drugs or biochemical agents for the treatment of middle and inner ear conditions. PMID:23323784

Hoskison, E; Daniel, M; Al-Zahid, S; Shakesheff, K M; Bayston, R; Birchall, J P

2013-01-01

354

Telemedicine Health Care Delivery System.  

National Technical Information Service (NTIS)

The Interactive Telemedicine Systems (ITS) system was specifically developed to address the ever widening gap between our medical care expertise and our medical care delivery system. The frustrating reality is that as our knowledge of how to diagnose and ...

J. H. Sanders

1991-01-01

355

Cyclodextrins in nasal drug delivery.  

PubMed

Nasal drug delivery is an attractive approach for the systemic delivery of high potency drugs with a low oral bioavailability due to extensive gastrointestinal breakdown and high hepatic first-pass effect. For lipophilic drugs nasal delivery is possible if they can be dissolved in the dosage form. Peptide and protein drugs often have a low nasal bioavailability because of their large size and hydrophilicity, resulting in poor transport properties across the nasal mucosa. Cyclodextrins are used to improve the nasal absorption of these drugs by increasing their aqueous solubility and/or by enhancing their nasal absorption. With several cyclodextrins very efficient nasal drug absorption has been reported, but also large interspecies differences have been found. Studies concerning the safety of cyclodextrins in nasal drug formulations demonstrate the non-toxicity of the cyclodextrins and also clinical data show no adverse effects. Therefore, some cyclodextrins can be expected to become effective and safe excipients in nasal drug delivery. PMID:10837708

Merkus; Verhoef; Marttin; Romeijn; van der Kuy PH; Hermens; Schipper

1999-03-01

356

Controlled Release of Simvastatin from Biomimetic ?-TCP Drug Delivery System  

PubMed Central

Simvastatin have been shown to induce bone formation and there is currently a urgent need to develop an appropriate delivery system to sustain the release of the drug to increase therapeutic efficacy whilst reducing side effects. In this study, a novel drug delivery system for simvastatin by means of hydrothermally converting marine exoskeletons to biocompatible beta-tricalcium phosphate was investigated. Furthermore, the release of simvastatin was controlled by the addition of an outer apatite coating layer. The samples were characterized by x-ray diffraction analysis, fourier transform infrared spectroscopy, scanning electron microscopy and mass spectroscopy confirming the conversion process. The in-vitro dissolution of key chemical compositional elements and the release of simvastatin were measured in simulated body fluid solution showing controlled release with reduction of approximately 25% compared with un-coated samples. This study shows the potential applications of marine structures as a drug delivery system for simvastatin.

Chou, Joshua; Ito, Tomoko; Bishop, David; Otsuka, Makoto; Ben-Nissan, Besim; Milthorpe, Bruce

2013-01-01

357

Brian Barry: innovative contributions to transdermal and topical drug delivery.  

PubMed

Brian Barry published over 300 research articles across topics ranging from colloid science, vasoconstriction and the importance of thermodynamics in dermal drug delivery to exploring the structure and organisation of the stratum corneum barrier lipids and numerous strategies for improving topical and transdermal drug delivery, including penetration enhancers, supersaturation, coacervation, eutectic formation and the use of varied liposomes. As research in the area blossomed in the early 1980s, Brian wrote the book that became essential reading for both new and established dermal delivery scientists, explaining the background mathematics and principles through to formulation design. Brian also worked with numerous scientists, as collaborators and students, who have themselves taken his rigorous approach to scientific investigation into their own research groups. This paper can only describe a small fraction of the many significant contributions that Brian made to the field during his 40-year academic career. PMID:23921110

Williams, A C

2013-01-01

358

Liposomes for Pulmonary Drug Delivery  

Microsoft Academic Search

\\u000a Liposomes have been widely used in pulmonary drug delivery for ­multiple applications including solubilization, sustained\\u000a release, cellular and intracellular ­targeting, minimization of toxicity, and facilitation of absorption. In this chapter,\\u000a formulation aspects, aerosolization, and an extensive overview of the use of pulmonary drug delivery of liposomes for disease\\u000a and drug classes are provided. Specifically, this chapter examines liposomes from in

Janani Swaminathan; Carsten Ehrhardt

359

Development of insulin delivery systems.  

PubMed

Delivery system of insulin is vital for its acceptance and adherence to therapy for achieving the glycemic targets. Enormous developments have occurred in the delivery system of insulin during the last twenty years and each improvement was aimed at two common goals: patients convenience and better glycemic control. Till to date, the various insulin delivery systems are: syringes/vials, injection aids, jet injectors, transmucosal delivery, transdermal delivery, external insulin infusion pump, implantable insulin pumps, insulin pens and insulin inhalers. Syringe/vial is the oldest and conventional method, still widely used and relatively cheaper. Modern plastic syringes are disposable, light weight with microfine needle for patients convenience and comfort. Oral route could be the most acceptable and viable, if the barriers can be overcome and under extensive trial. Insulin pen device is an important milestone in the delivery system of insulin as it is convenient, discrete, painless, attractive, portable with flexible life style and improved quality of life. More than 80% of European diabetic patients are using insulin pen. Future digital pen will have better memory option, blood glucose monitoring system, insulin dose calculator etc. Insulin infusion pump is a good option for the children, busy patients with flexible lifestyle and those who want to avoid multiple daily injections. Pulmonary route of insulin delivery is a promising, effective, non-invasive and acceptable alternative method. Exubera, the world first insulin inhaler was approved by FDA in 28 January 2006. But due to certain limitations, it has been withdrawn from the market in October 2007. The main concern of inhaled insulin are: long term pulmonary safety issues, cost effectiveness and user friendly device. In future, more acceptable and cost effective insulin inhaler will be introduced. Newer avenues are under extensive trial for better future insulin delivery systems. PMID:18285745

Siddiqui, N I; Siddiqui, Ni; Rahman, S; Nessa, A

2008-01-01

360

Cellulose esters in drug delivery  

Microsoft Academic Search

Cellulose esters have played a vital role in the development of modern drug delivery technology. They possess properties that\\u000a are not only well-suited to the needs of pharmaceutical applications, but that enable construction of drug delivery systems\\u000a that address critical patient needs. These properties include very low toxicity, endogenous and\\/or dietary decomposition products,\\u000a stability, high water permeability, high T\\u000a g,

Kevin J. Edgar

2007-01-01

361

Radiation delivery system and method  

DOEpatents

A radiation delivery system and method are described. The system includes a treatment configuration such as a stent, balloon catheter, wire, ribbon, or the like, a portion of which is covered with a gold layer. Chemisorbed to the gold layer is a radiation-emitting self-assembled monolayer or a radiation-emitting polymer. The radiation delivery system is compatible with medical catheter-based technologies to provide a therapeutic dose of radiation to a lesion following an angioplasty procedure.

Sorensen, Scott A. (Overland Park, KS); Robison, Thomas W. (Los Alamos, NM); Taylor, Craig M. V. (Jemez Springs, NM)

2002-01-01

362

Gold nanoparticles for nucleic Acid delivery.  

PubMed

Gold nanoparticles provide an attractive and applicable scaffold for delivery of nucleic acids. In this review, we focus on the use of covalent and noncovalent gold nanoparticle conjugates for applications in gene delivery and RNA-interference technologies. We also discuss challenges in nucleic acid delivery, including endosomal entrapment/escape and active delivery/presentation of nucleic acids in the cell. PMID:24599278

Ding, Ya; Jiang, Ziwen; Saha, Krishnendu; Kim, Chang Soo; Kim, Sung Tae; Landis, Ryan F; Rotello, Vincent M

2014-06-01

363

Novel approaches to pediatric vaccine delivery  

Microsoft Academic Search

Although currently available vaccines represent an outstanding success story in modern medicine and have had a dramatic effect on morbidity and mortality worldwide, it is clear that improvements in vaccine delivery are required. Vaccine delivery improvements may include the addition of novel injectable adjuvants, or the use of novel routes of delivery, including mucosal immunization. Mucosal delivery may be required

Derek T. O'Hagan; Rino Rappuoli

2006-01-01

364

Advances in oral transmucosal drug delivery  

Microsoft Academic Search

The successful delivery of drugs across the oral mucosa represents a continuing challenge, as well as a great opportunity. Oral transmucosal delivery, especially buccal and sublingual delivery, has progressed far beyond the use of traditional dosage forms with novel approaches emerging continuously. This review highlights the physiological challenges as well as the advances and opportunities for buccal\\/sublingual drug delivery. Particular

Viralkumar F. Patel; Fang Liu; Marc B. Brown

2011-01-01

365

Mineralized cyclodextrin nanoparticles for sustained protein delivery.  

PubMed

The extensive therapeutic potential of protein drugs has been severely limited by their instability and short biological half-lives in vivo. To prolong their therapeutic effects, a sustained delivery system is required. In this study, cyclodextrin-based polymeric nanoparticles (CD-NPs), mineralized by calcium phosphate as the diffusion barrier, were developed as a carrier for sustained protein delivery. Spherical CD-NPs were readily prepared by a conjugate, composed of ?-CD as the protein-binding moiety and carboxymethyl dextran as the substrate for mineralization in a physiological solution. Owing to the presence of carboxylic acids in CD-NPs, they were effectively mineralized by sequential addition of calcium nitrate and ammonium phosphate. The physicochemical characteristics of mineralized CD-NPs were characterized using FT-IR, thermogravimetric analysis, transmission electron microscopy and energy dispersive X-ray photoelectron spectroscopy. Mineralization reduced CD-NP particle size from 310 nm to 121 nm in PBS (pH 7.4) indicating the formation of compact nanoparticles. Carbonic anhydrase B (CAB), chosen as the model protein, was loaded into the mineralized CD-NPs with a high loading efficiency (80%) by a simple dialysis method. In vitro release tests showed that CAB was completely released from bare CD-NPs in 3 days. Interestingly, the mineralized CD-NPs released CAB in a sustained manner for 21 days, which was due to the stable calcium phosphate barrier inhibiting CAB release. The enzymatic activity of CAB, which was released from the nanoparticles, did not significantly deteriorate compared to native CAB. Overall, mineralized CD-NPs could be a promising carrier for sustained protein delivery. PMID:23911496

Sivasubramanian, Maharajan; Thambi, Thavasyappan; Park, Jae Hyung

2013-09-12

366

Nanogels for Oligonucleotide Delivery to the Brain  

PubMed Central

Systemic delivery of oligonucleotides (ODN) to the central nervous system is needed for development of therapeutic and diagnostic modalities for treatment of neurodegenerative disorders. Macromolecules injected in blood are poorly transported across the blood–brain barrier (BBB) and rapidly cleared from circulation. In this work we propose a novel system for ODN delivery to the brain based on nanoscale network of cross-linked poly(ethylene glycol) and polyethylenimine (“nanogel”). The methods of synthesis of nanogel and its modification with specific targeting molecules are described. Nanogels can bind and encapsulate spontaneously negatively charged ODN, resulting in formation of stable aqueous dispersion of polyelectrolyte complex with particle sizes less than 100 nm. Using polarized monolayers of bovine brain microvessel endothelial cells as an in vitro model this study demonstrates that ODN incorporated in nanogel formulations can be effectively transported across the BBB. The transport efficacy is further increased when the surface of the nanogel is modified with transferrin or insulin. Importantly the ODN is transported across the brain microvessel cells through the transcellular pathway; after transport, ODN remains mostly incorporated in the nanogel and ODN displays little degradation compared to the free ODN. Using mouse model for biodistribution studies in vivo, this work demonstrated that as a result of incorporation into nanogel 1 h after intravenous injection the accumulation of a phosphorothioate ODN in the brain increases by over 15 fold while in liver and spleen decreases by 2-fold compared to the free ODN. Overall, this study suggests that nanogel is a promising system for delivery of ODN to the brain.

Vinogradov, Serguei V.; Batrakova, Elena V.; Kabanov, Alexander V.

2009-01-01

367

Sustained growth factor delivery in tissue engineering applications.  

PubMed

The beautifully orchestrated complexity of the temporal spatial growth factor gradients during embryogenesis offer a striking contrast to systemic bolus administration that lack tissue specificity and sustained protein localization, often requiring supraphysiological protein doses to produce the desired therapeutic dose. These attributes may be responsible for clinically observed dangerous tissue overgrowth, inflammation, and even tumor formation. Growth factor delivery within an implanted scaffold is a very attractive way to modulate cell behavior. For short term delivery, proteins can be non-specifically adsorbed to the material surface or simply entrapped within the bulk scaffold. For more sustained delivery, many researchers have turned to the ever increasing list of covalent immobilization methods that have profound applications in purification, biosensing, imaging, and drug discovery by tethering proteins, nucleic acids, carbohydrates, synthetic polymers, small molecules, nanotubes, and even whole cells. This review focuses on the use of covalent immobilization to achieve sustained growth factor delivery for tissue engineering. Covalent immobilization techniques will be reviewed in terms of design, protein bioactivity/stability, efficiency, and spatiotemporal distribution. Further, the biological response to sustained growth factor delivery will also be covered, such as cell interaction, cell responsiveness, proliferation, differentiation, extracellular matrix production, and tissue regeneration. This focused review is anticipated to inform investigators on the selection of optimal immobilization strategies for their specific applications. PMID:24318193

Reed, Stephanie; Wu, Benjamin

2014-07-01

368

Matrices and Scaffolds for DNA Delivery in Tissue Engineering  

PubMed Central

Regenerative medicine aims to create functional tissue replacements, typically through creating a controlled environment that promotes and directs the differentiation of stem or progenitor cells, either endogenous or transplanted. Scaffolds serve a central role in many strategies by providing the means to control the local environment. Gene delivery from the scaffold represents a versatile approach to manipulating the local environment for directing cell function. Research at the interface of biomaterials, gene therapy, and drug delivery has identified several design parameters for the vector and the biomaterial scaffold that must be satisfied. Progress has been made towards achieving gene delivery within a tissue engineering scaffold, though the design principles for the materials and vectors that produce efficient delivery require further development. Nevertheless, these advances in obtaining transgene expression with the scaffold have created opportunities to develop greater control of either delivery or expression and to identify the best practices for promoting tissue formation. Strategies to achieve controlled localized expression within the tissue engineering scaffold will have broad application to the regeneration of many tissues, with great promise for clinical therapies.

De Laporte, Laura; Shea, Lonnie D.

2007-01-01

369

Women's preference for cesarean delivery and differences between Taiwanese women undergoing different modes of delivery  

Microsoft Academic Search

BACKGROUND: The rate of cesarean delivery was 35% in 2007 in Taiwan. It is unclear how many of the cesarean deliveries were without medical indications. Women's preference for cesarean delivery during their course of pregnancy has rarely been studied and therefore our objectives were to examine rate of cesarean deliveries without medical indications, to explore women's preference for cesarean delivery

Kuei-Hui Chu; Chen-Jei Tai; Chun-Sen Hsu; Mei-Chiang Yeh; Li-Yin Chien

2010-01-01

370

Thiomers for oral delivery of hydrophilic macromolecular drugs.  

PubMed

In recent years thiolated polymers (thiomers) have appeared as a promising new tool in oral drug delivery. Thiomers are obtained by the immobilisation of thio-bearing ligands to mucoadhesive polymeric excipients. By the formation of disulfide bonds with mucus glycoproteins, the mucoadhesive properties of thiomers are up to 130-fold improved compared with the corresponding unmodified polymers. Owing to the formation of inter- and intramolecular disulfide bonds within the thiomer itself, matrix tablets and particulate delivery systems show strong cohesive properties, resulting in comparatively higher stability, prolonged disintegration times and a more controlled drug release. The permeation of hydrophilic macromolecular drugs through the gastrointestinal (GI) mucosa can be improved by the use of thiomers. Furthermore, some thiomers exhibit improved inhibitory properties towards GI peptidases. The efficacy of thiomers in oral drug delivery has been demonstrated by various in vivo studies. A pharmacological efficacy of 1%, for example, was achieved in rats by oral administration of calcitonin tablets comprising a thiomer. Furthermore, tablets comprising a thiomer and pegylated insulin resulted in a pharmacological efficacy of 7% after oral application to diabetic mice. Low-molecular-weight heparin embedded in thiolated polycarbophil led to an absolute bioavailability of > or = 20% after oral administration to rats. In these studies, formulations comprising the corresponding unmodified polymer had only a marginal or no effect. These results indicate drug carrier systems based on thiomers appear to be a promising tool for oral delivery of hydrophilic macromolecular drugs. PMID:16296722

Bernkop-Schnürch, Andreas; Hoffer, Martin H; Kafedjiiski, Krum

2004-11-01

371

Peptide nanocarriers for intracellular delivery of photosensitizers.  

PubMed

Previously we have shown that recombinantly produced amphiphilic oligopeptides with amino acid sequence Ac-Ala-Ala-Val-Val-Leu-Leu-Leu-Trp-Glu-Glu spontaneously assemble into nano-sized vesicles with an average diameter of 120 nm. Moreover, peptide vesicles could be stabilized by introducing multiple cysteine residues within the hydrophobic domain of these amphiphilic oligopeptides, allowing the formation of intermolecular disulfide bridges. In this study, the cellular association and internalization of peptide vesicles were assessed. Flow cytometry and confocal laser-scanning microscopy showed that peptide vesicles were internalized by cells predominantly via adsorptive macropinocytosis. Furthermore, the potential of these peptide vesicles as delivery system for photosensitizers was explored. Water-insoluble phthalocyanines could be quantitatively entrapped within the hydrophobic domains of these peptide vesicles. Confocal laser-scanning microscopy analysis showed that internalized peptides co-localized with the phthalocyanine, suggesting that peptide vesicles are internalized in their intact form. Upon illumination, the phthalocyanine-containing peptide vesicles showed an active photodynamic response towards the cells leading to effective cell killing. In contrast, the free phthalocyanine or empty peptide vesicles did not show any cytotoxicity. In conclusion, this is the first demonstration that peptide vesicles show promise as delivery systems for photosensitizers to be used in photodynamic therapy. PMID:19766680

van Hell, Albert J; Fretz, Marjan M; Crommelin, Daan J A; Hennink, Wim E; Mastrobattista, Enrico

2010-02-15

372

Transcutaneous immunization with Intercell's vaccine delivery system.  

PubMed

Transcutaneous immunization (TCI) has become an attractive alternate route of immunization due to increase understanding of the skin immune system and to recent technical innovations in skin patch delivery systems. Basic principles of TCI have been demonstrated in animal and human studies, covering a variety of bacterial, viral, and cancer diseases. At Intercell, we have advanced two major platforms of TCI: 1) a needle-free vaccine delivery patch (VDP) and 2) a vaccine enhancement patch (VEP). Simplified, the VDP contains an antigen with or without an adjuvant that is administered on the skin; while the VEP contains only the adjuvant and is used in combination with an injected vaccine. In many of our TCI studies, the VDP or VEP is routinely applied on pretreated skin, in which the stratum corneum has been partially removed by mild abrasion. Recently, we have achieved technical breakthroughs in formulating and stabilizing vaccines in a dry patch format. For instance, a microplate-based screening process has been implemented to rapidly identify excipients, singularly or in combination, to stabilize biological macromolecules in patch blend formulations. A second technical innovation is our nonwoven (patch) disc matrix-supported drying technology, which allows efficient drying of our patch formulation blend to produce dry stable dosage forms of VDP or VEP. The low cost and the facileness in the manufacturing of VDP (or VEP) combined with the development of thermostable dry patches should improve the supply chain efficiency and reduce the dependence on cold chain. PMID:22682290

Seid, Robert C; Look, Jee Loon; Ruiz, Christian; Frolov, Vladimir; Flyer, David; Schafer, Jason; Ellingsworth, Larry

2012-06-19

373

In Situ Forming Polymeric Drug Delivery Systems  

PubMed Central

In situ forming polymeric formulations are drug delivery systems that are in sol form before administration in the body, but once administered, undergo gelation in situ, to form a gel. The formation of gels depends on factors like temperature modulation, pH change, presence of ions and ultra violet irradiation, from which the drug gets released in a sustained and controlled manner. Various polymers that are used for the formulation of in situ gels include gellan gum, alginic acid, xyloglucan, pectin, chitosan, poly(DL-lactic acid), poly(DL-lactide-co-glycolide) and poly-caprolactone. The choice of solvents like water, dimethylsulphoxide, N-methyl pyrrolidone, triacetin and 2-pyrrolidone for these formulations depends on the solubility of polymer used. Mainly in situ gels are administered by oral, ocular, rectal, vaginal, injectable and intraperitoneal routes. The in situ gel forming polymeric formulations offer several advantages like sustained and prolonged action in comparison to conventional drug delivery systems. The article presents a detailed review of these types of polymeric systems, their evaluation, advancements and their commercial formulations. From a manufacturing point of view, the production of such devices is less complex and thus lowers the investment and manufacturing cost.

Madan, M.; Bajaj, A.; Lewis, S.; Udupa, N.; Baig, J. A.

2009-01-01

374

Controlled release polymeric ocular delivery of acyclovir.  

PubMed

The aim of the present study was to formulate and evaluate controlled release polymeric ocular delivery of acyclovir. Reservoir-type ocular inserts were fabricated by sandwiching hydroxypropyl methylcellulose (HPMC) matrix film containing acyclovir between two rate controlling membranes of cellulose acetate phthalate (CAP). The solubility and dissolution rate of poorly soluble acyclovir was enhanced by preparing binary systems with beta-cyclodextrin and then incorporated into HPMC matrix. Nine formulations (AB-1 to AB-9) with varying ratio of HPMC (drug matrix) and CAP (rate controlling membrane) were developed and sterilized by gamma radiation. The formulations were subjected to various physico-chemical evaluations. The in vitro release profile of all the formulations showed a steady, controlled drug release up to 20 h with non-Fickian diffusion behavior. A high correlation coefficient found between in vitro/in vivo release rate studies. Formation of acyclovir complex was confirmed by differential scanning calorimetry. In addition, dissolution rate studies revealed improved solubility of acyclovir when complexed with beta-cyclodextrin. Stability studies showed that the ocular inserts could be stored safely at study storage conditions. In conclusion, the present study demonstrated controlled release formulation of acyclovir inserts for ocular delivery using biodegradable polymers. PMID:19772377

Deshpande, Praful Balavant; Dandagi, Panchaxari; Udupa, Nayanabhirama; Gopal, Shavi V; Jain, Samata S; Vasanth, Surenalli G

2010-01-01

375

Organo hydrogel hybrids. Formation of reservoirs for protein delivery.  

PubMed

A biodegradable organo hydrogel hybrid material is presented, which is formed through the water uptake of a phosphoryl choline zwitterionomer (PC ionomer). The water uptake and subsequent swelling is induced by the phosphoryl choline (PC) end group functionality. The nonfunctional poly(trimethylene carbonate) is hydrophobic and as such does not absorb any water. Disks of the PC ionomer showed significant water uptake, typically above 90 wt % when fully swollen. This high water uptake triggered us to utilize the material for drug and protein loading and subsequent release. Fluorescein and fluorescein-labeled proteins were used as simple models for the loading and release characteristics of the material which was studied by fluorescence spectroscopy. The rate of release of the loaded molecules was compared, and it was shown that the release rate was similar for FITC and insulin but slightly slower for albumin. These results suggest that the PC ionomer may be used as a biodegradable and low elastic modulus material with an additional drug and/or protein release capacity. Such materials are of particular interest for use in a variety of applications in vivo, for example as drug eluting stents. PMID:16283731

Nederberg, Fredrik; Watanabe, Junji; Ishihara, Kazuhiko; Hilborn, Jöns; Bowden, Tim

2005-01-01

376

Therapeutic angiogenesis: controlled delivery of angiogenic factors  

PubMed Central

Therapeutic angiogenesis aims at treating ischemic diseases by generating new blood vessels from existing vasculature. It relies on delivery of exogenous factors to stimulate neovasculature formation. Current strategies using genes, proteins and cells have demonstrated efficacy in animal models. However, clinical translation of any of the three approaches has proved to be challenging for various reasons. Administration of angiogenic factors is generally considered safe, according to accumulated trials, and offers off-the-shelf availability. However, many hurdles must be overcome before therapeutic angiogenesis can become a true human therapy. This article will highlight protein-based therapeutic angiogenesis, concisely review recent progress and examine critical challenges. We will discuss growth factors that have been widely utilized in promoting angiogenesis and compare their targets and functions. Lastly, since bolus injection of free proteins usually result in poor outcomes, we will focus on controlled release of proteins.

Chu, Hunghao; Wang, Yadong

2013-01-01

377

Transdermal Insulin Delivery Using Microdermabrasion  

PubMed Central

Purpose Transdermal insulin delivery is an attractive needle-free alternative to subcutaneous injection conventionally used to treat diabetes. However, skin’s barrier properties prevent insulin permeation at useful levels. Methods We investigated whether microdermabrasion can selectively remove skin’s surface layers to increase skin permeability as a method to administer insulin to diabetic rats. We further assessed the relative roles of stratum corneum and viable epidermis as barriers to insulin delivery. Results Pretreatment of skin with microdermabrasion to selectively remove stratum corneum did not have a significant effect on insulin delivery or reduction in blood glucose level (BGL). Removal of full epidermis by microdermabrasion significantly reduced BGL, similar to the positive control involving subcutaneous injection of 0.1U insulin. Significant pharmacokinetic differences between microdermabrasion and subcutaneous injection were faster time to peak insulin concentration after injection and larger peak insulin concentration and area-under-the-curve after microdermabrasion. Conclusions Microdermabrasion can increase skin permeability to insulin at levels sufficient to reduce BGL. Viable epidermis is a barrier to insulin delivery such that removal of full epidermis enables significantly more insulin delivery than removal of stratum corneum alone.

Andrews, Samantha; Lee, Jeong Woo; Choi, Seong-O

2011-01-01

378

Breech deliveries and cesarean section.  

PubMed

Breech presentation is the most common malpresentation, with about 3-4% of singleton fetuses presenting breech at delivery. Management of breech presentation has been a contentious issue with a lowering threshold for cesarean section in recent years. Perinatal mortality and morbidity are estimated to be three times that of comparable infants with vertex presentation. Breech presentation is commonly associated with certain adverse maternal and fetal factors which inherently give rise to increased perinatal morbidity and mortality. At present, most obstetricians favor cesarean delivery for uncomplicated pre-term breech. Controlled prospective studies have shown that the outcome of breech fetuses weighing more than 1500 g was not dependent on the mode of delivery. A more recent review from the Cochrane database by Grant does not justify a policy of elective cesarean section for pre-term breech. Vaginal delivery is preferred if the following criteria are met: frank breech only, estimated fetal weight of 2500-3500 g, adequate pelvimetry without hyperextended head, normal progression of labor, no evidence of fetal hypoxia under continuous fetal monitoring, and maternal weight under 90 kg. Vaginal delivery of frank breech at term may be just as safe as cesarean section when careful selection criteria are used. If these criteria are not fulfilled, or fetal monitoring cannot be performed, cesarean section is advisable. PMID:14601264

Papp, Zoltán

2003-01-01

379

Microelectronic control of drug delivery.  

PubMed

Microelectronic control of drug delivery devices enables precise management of drug delivery profiles. Iontophoresis patches offer microelectronic control over delivery in a noninvasive manner, but these are limited to the administration of relatively small molecules at small doses. Infusion pumps are widely used for delivery of insulin and other drugs; however, they require an invasive catheter that many patients find inconvenient and can be a site of infection. Implanted pumps avoid these problems, but they require long-term commitment associated with surgical implantation. An alternative is an implanted microchip containing many protected reservoirs filled with drug powder that is selectively released under microelectronic control. This device offers the promise of long-term drug stability in the solid state and precise digital drug dosing. Building on more than 10 years of preclinical studies, this wirelessly controlled microchip technology recently underwent a first-in-human clinical study. The microchip was implanted subcutaneously in the abdomen of eight female patients with osteoporosis. A remote operator was able to establish a wireless link with the microchip to program the schedule of human parathyroid hormone dosing from the device. This study showed that the wireless microchips produced pharmacokinetics similar to those from subcutaneous injections of the drug and produced less variable drug levels in the blood. There were also no toxic or adverse events due to the microchip or drug. This study represents an important step towards more widespread use of microelectronic control of drug delivery to improve pharmaceutical therapies. PMID:22905837

Guo, Xin Dong; Prausnitz, Mark R

2012-07-01

380

Bladder Injury During Cesarean Delivery  

PubMed Central

Cesarean section is the most common surgery performed in the United States with over 30% of deliveries occurring via this route. This number is likely to increase given decreasing rates of vaginal birth after cesarean section (VBAC) and primary cesarean delivery on maternal request, which carries the inherent risk for intraoperative complications. Urologic injury is the most common injury at the time of either obstetric or gynecologic surgery, with the bladder being the most frequent organ damaged. Risk factors for bladder injury during cesarean section include previous cesarean delivery, adhesions, emergent cesarean delivery, and cesarean section performed at the time of the second stage of labor. Fortunately, most bladder injuries are recognized at the time of surgery, which is important, as quick recognition and repair are associated with a significant reduction in patient mortality. Although cesarean delivery is a cornerstone of obstetrics, there is a paucity of data in the literature either supporting or refuting specific techniques that are performed today. There is evidence to support double-layer closure of the hysterotomy, the routine use of adhesive barriers, and performing a Pfannenstiel skin incision versus a vertical midline subumbilical incision to decrease the risk for bladder injury during cesarean section. There is also no evidence that supports the creation of a bladder flap, although routinely performed during cesarean section, as a method to reduce the risk of bladder injury. Finally, more research is needed to determine if indwelling catheterization, exteriorization of the uterus, and methods to extend hysterotomy incision lead to bladder injury.

Tarney, Christopher M.

2013-01-01

381

Ultrasound-enhanced drug delivery for efficient cancer therapy  

Microsoft Academic Search

Poor penetration of anti-cancer drugs through tumor vasculature and cancer cell membrane as well as slow diffusion of the drugs in the interstitium limit efficacy of cancer chemo- and biotherapy. Recently we proposed to use ultrasound-induced cavitation (formation, growth, and collapse of microbubbles) to enhance anti-cancer drug delivery through these barriers. Cavitation can be selectively induced in tumors by using

I. V. Larina; B. M. Evers; C. Bartels; T. V. Ashitkov; K. V. Larin; R. O. Esenaliev

2002-01-01

382

Thrombininhibitor complexes in the blood during and after delivery  

Microsoft Academic Search

Activation of coagulation leads to generation of thrombin which in turn is inactivated by the formation of thrombin-antithrombin (TAT) complexes, and thrombin-heparin cofactor complexes (T-HCII). These complexes were measured in plasma by ELISA methods. During normal delivery, the median TAT level in ten women increased from 4.1 to 7.8 times the median normal reference level. There was great individual variation,

Terje Andersson; Bjørg Lorentzen; Heidi Høgdahl; Torun Clausen; Marie-Christine Mowinckel; Ulrich Abildgaard

1996-01-01

383

Maternal Nutrition and Preterm Delivery  

Microsoft Academic Search

\\u000a \\u000a \\u000a Key Points\\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a The rate of preterm delivery in the United States has increased by more than 25% in the past 20 yr.\\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a Low weight before pregnancy may be associated with increased risk for preterm delivery.\\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a Inadequate weight gain, particularly in the third trimester, may be associated with increased risk for preterm delivery.\\u000a \\u000a \\u000a \\u000a • \\u000a \\u000a \\u000a Fasting and intervals longer

Theresa O. Scholl

384

New Evidence for the Role of Emerging Flux in a Solar Filament's Slow Rise Preceding its CME-Producing Fast Eruption  

NASA Technical Reports Server (NTRS)

We observe the eruption of a large-scale (approx.300,000 km) quiet-region solar filament, leading to an Earth-directed "halo" coronal mass ejection (CME). We use coronal imaging data in EUV from the EUV Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO) satellite, and in soft X-rays (SXRs) from the Soft X-ray Telescope (SXT) on the Yohkoh satellite. We also use spectroscopic data from the Coronal Diagnostic Spectrometer (CDS), magnetic data from the Michelson Doppler Imager (MDI), and white-light coronal data from the Large Angle and Spectrometric Coronagraph Experiment (LASCO), all on SOHO. Initially the filament shows a slow (approx.1 km/s projected against the solar disk) and approximately constant-velocity rise for about 6 hours, before erupting rapidly, reaching a velocity of approx. 8 km/s over the next approx. 25 min. CDS Doppler data show Earth-directed filament velocities ranging from < 20 km/s (the noise limit) during the slow-rise phase, to approx. 100 km/s-1 early in the eruption. Beginning within 10 hours prior to the start of the slow rise, localized new magnetic flux emerged near one end of the filament. Near the start of and during the slow-rise phase, SXR microflaring occurred repeatedly at the flux-emergence site, in conjunction with the development of a fan of SXR illumination of the magnetic arcade over the filament. The SXR microflares, development of the SXR fan, and motion of the slow-rising filament are all consistent with "tether-weakening" reconnection occurring between the newly-emerging flux and the overlying arcade field containing the filament field. The microflares and fan structure are not prominent in EUV, and would not have been detected without the SXR data. Standard "twin dimmings" occur near the location of the filament, and "remote dimmings" and "brightenings" occur further removed from the filament.

Sterling, Alphonse C.; Harra, Louis K.; Moore, Ronald L.

2007-01-01

385

Predictions and observations of HF radio propagation in the northerly ionosphere: The effect of the solar flares and a weak CME in early January 2014.  

NASA Astrophysics Data System (ADS)

We have previously reported on a significant new multi-national project to provide improved predictions and forecasts of HF radio propagation for commercial aircraft operating on trans-polar routes. In these regions, there are limited or no VHF air-traffic control facilities and geostationary satellites are below the horizon. Therefore HF radio remains important in maintaining communications with the aircraft at all times. Space weather disturbances can have a range of effects on the ionosphere and hence HF radio propagation - particularly in the polar cap. While severe space weather effects can lead to a total loss of communications (i.e. radio blackout), less intense events can still cause significant disruption. In this paper we will present the effect of a series of M and X class solar flares and a relatively weak CME on HF radio performance from 6 to 13 January 2014. This is an interesting interval from the point of view of HF radio propagation because while the solar effects on the ionosphere are significant, except for an interval of approximately 12 hours duration, they are not so intense as to produce a complete radio blackout on all paths. Observations of the signal-to-noise ratio, direction of arrival, and time of flight of HF radio signals on six paths (one entirely within the polar cap, three trans-auroral, and two sub-auroral) will be presented together with riometer measurements of the ionospheric absorption. Global maps of D-region absorption (D-region absorption prediction, DRAP) inferred from satellite measurements of the solar wind parameters will be compared with the HF and riometer observations. In addition, a ray-tracing model using a realistic background ionosphere and including localised features found in the ionospheric polar cap (e.g. polar patches and arcs) will be used to model the expected and observed HF radio propagation characteristics.

Hallam, Jonathan; Stocker, Alan J.; Warrington, Mike; Siddle, Dave; Zaalov, Nikolay; Honary, Farideh; Rogers, Neil; Boteler, David; Danskin, Donald

2014-05-01

386

New Methods of Drug Delivery  

NASA Astrophysics Data System (ADS)

Conventional forms of drug administration generally rely on pills, eye drops, ointments, and intravenous solutions. Recently, a number of novel drug delivery approaches have been developed. These approaches include drug modification by chemical means, drug entrapment in small vesicles that are injected into the bloodstream, and drug entrapment within pumps or polymeric materials that are placed in desired bodily compartments (for example, the eye or beneath the skin). These techniques have already led to delivery systems that improve human health, and continued research may revolutionize the way many drugs are delivered.

Langer, Robert

1990-09-01

387

Fetal outcomes of elective delivery.  

PubMed

Retrospective observational studies have suggested that delivery at or beyond 39 weeks has numerous neonatal benefits including less need for respiratory support, fewer neurodevelopmental delays and lower health care costs. This has lead governmental agencies, and professional organizations to endorse a policy of limiting elective delivery prior to 39 weeks. Nonetheless, studies which have examined the implications of instituting such policies, have demonstrated mixed benefits and signaled some concerns about unintended outcomes, such as stillbirth. This chapter will detail the evidence that these policies have on certain neonatal outcomes and examine why the promise of such policies may remain unfilled. PMID:24709710

Hoffman, Matthew K; Merriam, Audrey A; Ehrenthal, Deborah B

2014-06-01

388

From service delivery to application delivery in the telecommunication industry  

Microsoft Academic Search

Currently, in the Telecom industry all over the world the move towards service oriented infrastructures based on IP, IP Multimedia Subsystem (IMS), Service Oriented Architectures (SOA) and Service Delivery Platforms (SDP) can be observed and Communication Service Providers are opening parts of their core infrastructure and interfaces to third party developers. But there is a gap between application developer communities

Christian Menkens

2010-01-01

389

Delivery System, 2003-2004.  

ERIC Educational Resources Information Center

This workshop guide for financial aid administrators provides training in the federal student financial aid delivery system. An introduction enables the participant to share some information about his or her responsibilities and to reflect on the relevance of the training to the job. Session 1, "Application Systems," identifies methods of applying…

Office of Federal Student Aid (ED), Washington, DC.

390

Delivery system for appetite suppressant  

US Patent & Trademark Office Database

The invention relates to a topical delivery system suitable for application to the lips, comprising at least one naturally occurring oil, at least one naturally occurring wax, and at least one naturally occurring diet aid. The invention also relates to a method for controlling weight in an individual by applying such a composition to the lips.

2007-07-24

391

Career Information Delivery Systems Inventory.  

ERIC Educational Resources Information Center

This inventory highlights similarities and differences between 19 computerized career information delivery systems (CIDS) so practitioners may make more informed choices concerning the adoption of such systems, and policymakers may monitor the developing scope of system features and costs. It was developed through a survey of computer products…

Olson, Gerald T.; Whitman, Patricia D.

392

Valuing a Document Delivery System.  

ERIC Educational Resources Information Center

Users of a search/document delivery service in a large engineering firm were surveyed to determine the amount and relevancy of information received, time saved by using the service, dollar value of information received, number of employees using or seeing the information, and any improvement in the firm's competitive position. (EM)

Estabrook, Leigh Stewart

1986-01-01

393

Multifunctional nanorods for gene delivery  

NASA Astrophysics Data System (ADS)

The goal of gene therapy is to introduce foreign genes into somatic cells to supplement defective genes or provide additional biological functions, and can be achieved using either viral or synthetic non-viral delivery systems. Compared with viral vectors, synthetic gene-delivery systems, such as liposomes and polymers, offer several advantages including ease of production and reduced risk of cytotoxicity and immunogenicity, but their use has been limited by the relatively low transfection efficiency. This problem mainly stems from the difficulty in controlling their properties at the nanoscale. Synthetic inorganic gene carriers have received limited attention in the gene-therapy community, the only notable example being gold nanoparticles with surface-immobilized DNA applied to intradermal genetic immunization by particle bombardment. Here we present a non-viral gene-delivery system based on multisegment bimetallic nanorods that can simultaneously bind compacted DNA plasmids and targeting ligands in a spatially defined manner. This approach allows precise control of composition, size and multifunctionality of the gene-delivery system. Transfection experiments performed in vitro and in vivo provide promising results that suggest potential in genetic vaccination applications.

Salem, Aliasger K.; Searson, Peter C.; Leong, Kam W.

2003-10-01

394

Hydrogel nanoparticles in drug delivery  

Microsoft Academic Search

Hydrogel nanoparticles have gained considerable attention in recent years as one of the most promising nanoparticulate drug delivery systems owing to their unique potentials via combining the characteristics of a hydrogel system (e.g., hydrophilicity and extremely high water content) with a nanoparticle (e.g., very small size). Several polymeric hydrogel nanoparticulate systems have been prepared and characterized in recent years, based

Mehrdad Hamidi; Amir Azadi; Pedram Rafiei

2008-01-01

395

TARGETED DELIVERY OF INHALED PROTEINS  

EPA Science Inventory

ETD-02-047 (Martonen) GPRA # 10108 TARGETED DELIVERY OF INHALED PROTEINS T. B. Martonen1, J. Schroeter2, Z. Zhang3, D. Hwang4, and J. S. Fleming5 1Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, Research Triangle Park...

396

Antisense oligonucleotides: strategies for delivery  

Microsoft Academic Search

The development of antisense oligonucleotides as therapeutic agents has progressed significantly over the past 10–15 years. In order for antisense oligodeoxynucleotides to become effective therapeutic agents, improvement in the delivery and distribution of these compounds must occur. In addition to therapeutic uses, antisense oligonucleotides should allow for the characterization of discrete receptor and enzyme subtypes and their splice variants—identified by

Keith J Miller; Sudip K Das

1998-01-01

397

Mathematical modeling of drug delivery.  

PubMed

Due to the significant advances in information technology mathematical modeling of drug delivery is a field of steadily increasing academic and industrial importance with an enormous future potential. The in silico optimization of novel drug delivery systems can be expected to significantly increase in accuracy and easiness of application. Analogous to other scientific disciplines, computer simulations are likely to become an integral part of future research and development in pharmaceutical technology. Mathematical programs can be expected to be routinely used to help optimizing the design of novel dosage forms. Good estimates for the required composition, geometry, dimensions and preparation procedure of various types of delivery systems will be available, taking into account the desired administration route, drug dose and release profile. Thus, the number of required experimental studies during product development can be significantly reduced, saving time and reducing costs. In addition, the quantitative analysis of the physical, chemical and potentially biological phenomena, which are involved in the control of drug release, offers another fundamental advantage: The underlying drug release mechanisms can be elucidated, which is not only of academic interest, but a pre-requisite for an efficient improvement of the safety of the pharmaco-treatments and for effective trouble-shooting during production. This article gives an overview on the current state of the art of mathematical modeling of drug delivery, including empirical/semi-empirical and mechanistic realistic models. Analytical as well as numerical solutions are described and various practical examples are given. One of the major challenges to be addressed in the future is the combination of mechanistic theories describing drug release out of the delivery systems with mathematical models quantifying the subsequent drug transport within the human body in a realistic way. Ideally, the effects of the design parameters of the dosage form on the resulting drug concentration time profiles at the site of action and the pharmacodynamic effects will become predictable. PMID:18822362

Siepmann, J; Siepmann, F

2008-12-01

398

The Cultural Geography of Health Care Delivery.  

ERIC Educational Resources Information Center

This article shows how health care delivery is related to cultural or human geography. This is accomplished by describing health care delivery in terms of 12 popular themes of cultural geography. (JDH)

Gesler, Wilbert M.

1987-01-01

399

Teletex Based Electronic Document Delivery (Project HERMES).  

ERIC Educational Resources Information Center

Project HERMES is characterized by participation of publishers, industrial and public libraries, and national government, and by use of Teletex for both document ordering and delivery. Provision of three facilities (electronic document ordering and delivery, automatic document delivery, electronic mail) to pilot group of 60 organizations is…

Amy, Susan J.

1985-01-01

400

MEMS based polymeric drug delivery system  

Microsoft Academic Search

In this paper, MEMS based polymeric drug delivery system for the treatment of cardiovascular disorder such as hypertension is presented. The major components of proposed system are drug delivery device, blood pressure sensor, flow sensor, electronic module, and power supply. Drug delivery device consists of piezoelectric actuator and reservoir integrated with side open polymeric microneedles. The in-depth theoretical and numerical

M. W. Ashraf; S. Tayyaba; N. Afzulpurkar

2010-01-01

401

Controlled Release Systems for DNA Delivery  

Microsoft Academic Search

Adapting controlled release technologies to the delivery of DNA has the potential to overcome extracellular barriers that limit gene therapy. Controlled release systems can enhance gene delivery and increase the extent and duration of transgene expression relative to more traditional delivery methods (e.g., injection). These systems typically deliver vectors locally, which can avoid distribution to distant tissues, decrease toxicity to

Angela K. Pannier; Lonnie D. Shea

2004-01-01

402

Nasal drug delivery: new developments and strategies  

Microsoft Academic Search

The use of the nasal route for the delivery of challenging drugs has created much interest in recent years in the pharmaceutical industry. Consequently, drug delivery companies are actively pursuing the development of novel nasal drug-delivery systems and the exploitation of these for administration of conventional generic drugs and peptides, both in-house and with partners in the pharmaceutical industry. This

Lisbeth Illum

2002-01-01

403

Cesarean delivery and anal sphincter injury  

Microsoft Academic Search

Objective: Cesarean delivery has been thought to prevent all obstetric anal sphincter damage. The objective of this study was to determine the relationship between the timing of cesarean during primiparous delivery and injury to the anal sphincter mechanism.Methods: A prospective observational study was conducted, using a continence questionnaire and anorectal physiology assessment before and six weeks after primiparous delivery. A

Michelle Fynes; Valerie S Donnelly; P. Ronan O’Connell; Colm O’Herlihy

1998-01-01

404

43 CFR 418.7 - Who may receive irrigation deliveries.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 false Who may receive irrigation deliveries. 418.7 Section 418.7...Water Delivery § 418.7 Who may receive irrigation deliveries. Project irrigation water deliveries may be made only to...

2013-10-01

405

Carboxymethyl starch and lecithin complex as matrix for targeted drug delivery: I. Monolithic mesalamine forms for colon delivery.  

PubMed

For drugs expected to act locally in the colon, and for successful treatment, a delivery device is necessary, in order to limit the systemic absorption which decreases effectiveness and causes important side effects. Various delayed release systems are currently commercialized; most of them based on pH-dependent release which is sensitive to gastrointestinal pH variation. This study proposes a novel excipient for colon delivery. This new preparation consists in the complexation between carboxymethyl starch (CMS) and Lecithin (L). As opposed to existing excipients, the new complex is pH-independent, inexpensive, and easy to manufacture and allows a high drug loading. FTIR, X-ray, and SEM structural analysis all support the hypothesis of the formation of a complex. By minor variation of the excipient content within the tablet, it is possible to modulate the release time and delivery at specific sites of the gastrointestinal tract. This study opens the door to a new pH-independent delivery system for mesalamine targeted administration. Our novel formulation fits well with the posology of mesalamine, used in the treatment of Inflammatory Bowel Disease (IBD), which requires repeated administrations (1g orally four times a day) to maintain a good quality of life. PMID:23562535

Mihaela Friciu, Maria; Canh Le, Tien; Ispas-Szabo, Pompilia; Mateescu, Mircea Alexandru

2013-11-01

406

Thiomers: potential excipients for non-invasive peptide delivery systems.  

PubMed

In recent years thiolated polymers or so-called thiomers have appeared as a promising alternative in the arena of non-invasive peptide delivery. Thiomers are generated by the immobilisation of thiol-bearing ligands to mucoadhesive polymeric excipients. By formation of disulfide bonds with mucus glycoproteins, the mucoadhesive properties of these polymers are improved up to 130-fold. Due to formation of inter- and intramolecular disulfide bonds within the thiomer itself, dosage forms such as tablets or microparticles display strong cohesive properties resulting in comparatively higher stability, prolonged disintegration times and a more controlled release of the embedded peptide drug. The permeation of peptide drugs through mucosa can be improved by the use of thiolated polymers. Additionally some thiomers exhibit improved inhibitory properties towards peptidases. The efficacy of thiomers in non-invasive peptide delivery could be demonstrated by various in vivo studies. Tablets comprising a thiomer and pegylated insulin, for instance, resulted in a pharmacological efficacy of 7% after