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Sample records for anchoring dendritic tips

  1. Targeting of RGS7/Gbeta5 to the dendritic tips of ON-bipolar cells is independent of its association with membrane anchor R7BP.

    PubMed

    Cao, Yan; Song, Hongman; Okawa, Haruhisa; Sampath, Alapakkam P; Sokolov, Maxim; Martemyanov, Kirill A

    2008-10-08

    Complexes of regulator of G-protein signaling (RGS) proteins with G-protein beta5 (Gbeta5) subunits are essential components of signaling pathways that regulate the temporal characteristics of light-evoked responses in vertebrate retinal photoreceptors and ON-bipolar cells. Recent studies have found that RGS/Gbeta5 complexes bind to a new family of adapter proteins, R9AP (RGS9 anchor protein) and R7 family binding protein (R7BP), that in case of the RGS9/Gbeta5 complex were shown to determine its precise subcellular targeting to either the outer segment of photoreceptors or postsynaptic structures of striatal neurons, respectively. In this study, we establish that another trimeric complex consisting of RGS7, Gbeta5, and R7BP subunits is specifically targeted to the dendritic tips of retinal bipolar cells. However, examination of the mechanisms of complex targeting in vivo surprisingly revealed that the delivery of RGS7/Gbeta5 to the dendrites of ON-bipolar cells occurs independently of its association with R7BP. These findings provide a new mechanism for adapter-independent targeting of RGS/Gbeta5 complexes.

  2. Tip selection in three-dimensional dendrites

    NASA Astrophysics Data System (ADS)

    Foster, M. R.; Tanveer, S.

    2004-11-01

    Dendrites are well-known to have a fully three-dimensional structure, often with four equally-spaced fins emanating from the steady parabolic tip, the pattern for which has now a good theoretical foundation.(McFadden, Coriell & Sekerka, J. Crys. Growth) 208 (2000) The four fins are of course related to four-fold crystalline anisotropy of quite small magnitude. We follow Tanveer(Tanveer, S. Phys. Rev. A) 40 (1989) in carefully exploring the matching of the inner solution in the neighborhood of the singularity nearest the real line to the small-surface-energy regular perturbation expansion, in order to obtain the (selected) tip radius and the amplitude of the fin. We consider the case for which the anisotropy parameter, α, is much larger than a dimensionless capillary length to the 4/7 power. We confirm what was already found in a slightly different parameter range(Ben Amar & Brener, Phys. Rev. Lett.) 71 (1993)--that the inner equation is essentially that of the two-dimensional case, with azimuthally-dependent parameters. We compare our results with those of Ben Amar & Brener.

  3. Fundamentals of dendritic solidification. I - Steady-state tip growth. II - Development of sidebranch structure

    NASA Technical Reports Server (NTRS)

    Huang, S.-C.; Glicksman, M. E.

    1981-01-01

    Systematic measurements of dendrite tip radius and growth velocity in succinonitrile reveal that consideration of dendrite tip stability should be incorporated into the heat transfer theory to determine the steady-state dendritic growth condition. The dendritic stability criterion measured is 2 alpha d0/VR squared = 0.0195, where V is the dendritic growth velocity, R is the dendritic tip radius, alpha is the liquid thermal diffusivity, and d0 is a capillary length defined in the text. Several dendritic stability models are reviewed and discussed in comparison to the present experimental results.

  4. Phase-field-crystal investigation of the morphology of a steady-state dendrite tip on the atomic scale.

    PubMed

    Tang, Sai; Wang, Jincheng; Li, Junjie; Wang, Zhijun; Guo, Yaolin; Guo, Can; Zhou, Yaohe

    2017-06-01

    Through phase-field-crystal (PFC) simulations, we investigated, on the atomic scale, the crucial role played by interface energy anisotropy and growth driving force during the morphological evolution of a dendrite tip at low growth driving force. In the layer-by-layer growth manner, the interface energy anisotropy drives the forefront of the dendrite tip to evolve to be highly similar to the corner of the corresponding equilibrium crystal from the aspects of atom configuration and morphology, and thus affects greatly the formation and growth of a steady-state dendrite tip. Meanwhile, the driving force substantially influences the part behind the forefront of the dendrite tip, rather than the forefront itself. However, as the driving force increases enough to change the layer-by-layer growth to the multilayer growth, the morphology of the dendrite tip's forefront is completely altered. Parabolic fitting of the dendrite tip reveals that an increase in the influence of interface energy anisotropy makes dendrite tips deviate increasingly from a parabolic shape. By quantifying the deviations under various interface energy anisotropies and growth driving forces, it is suggested that a perfect parabola is an asymptotic limit for the shape of the dendrite tips. Furthermore, the atomic scale description of the dendrite tip obtained in the PFC simulation is compatible with the mesoscopic results obtained in the phase-field simulation in terms of the dendrite tip's morphology and the stability criterion constant.

  5. Thermal and solutal conditions at the tips of a directional dendritic growth front

    NASA Technical Reports Server (NTRS)

    Mccay, T. D.; Mccay, Mary H.; Hopkins, John A.

    1991-01-01

    The line-of-sight averaged, time-dependent dendrite tip concentrations for the diffusion dominated vertical directional solidification of a metal model (ammonium chloride and water) were obtained by extrapolating exponentially fit diffusion layer profiles measured using a laser interferometer. The tip concentrations were shown to increase linearly with time throughout the diffusion dominated growth process for an initially stagnant dendritic array. The process was terminated for the cases chosen by convective breakdown suffered when the conditionally stable diffusion layer exceeded the critical Rayleigh criteria. The transient tip concentrations were determined to significantly exceed the values predicted for steady state, thus producing much larger constitutional undercoolings. This has ramifications for growth speeds, arm spacings and the dendritic structure itself.

  6. Effects of Applied Electric Current on the Tip Radius and the Universal Amplitude Coefficient of a Single Growing Dendrite

    NASA Astrophysics Data System (ADS)

    Nasresfahani, Mohammad Reza; Niroumand, Behzad; Kermanpur, Ahmad; Raeissi, Mehdi

    2016-09-01

    Modification of solidification structures by applying electric current has been the subject of interest in recent years. However, the exact relationships between the dendrite growth parameters and the current density are not yet clear. The dendrite tip geometry is an important growth parameter which can be characterized using the dendrite tip radius and the universal amplitude coefficient. In this paper, the dendrite tip shape was investigated in the absence and presence of an electric field using a transparent model material, i.e. the succinonitrile-acetone alloy. The results showed that both dendrite tip radius and universal amplitude coefficient increased by increasing the applied current density. The increase in the tip radius was attributed to the Joule heat produced at the solid-liquid interface which reduced the interface undercooling. The increase in the universal amplitude coefficient was postulated to be due to the changes in the distribution coefficient of the alloy system which would result in higher solute concentration in front of the solid-liquid interface. Owing to the increased universal amplitude coefficient, more prominent dendritic fins were observed at dendrites tips under electric current.

  7. Time Dependence of Tip Morphology during Cellular/Dendritic Arrayed Growth

    NASA Technical Reports Server (NTRS)

    Song, H.; Tewari, S. N.

    1996-01-01

    Succinonitrile-1.9 wt pct acetone has been directionally solidified in 0.7 X 0.7-cm-square cross section pyrex ampoules in order to observe the cell/dendrite tip morphologies, not influenced by the 'wall effects', which are present during growth in the generally used thin (about 200 gm) crucibles. The tips do not maintain a steady-state shape, as is generally assumed. Instead, they fluctuate within a shape envelope. The extent of fluctuation increases with decreasing growth speed, as the micro structure changes from the dendritic to cellular. The influence of natural convection has been examined by comparing these morphologies with those grown, without convection, in the thin ampoules.

  8. Robotic Single-Site Sacrocolpopexy Using Barbed Suture Anchoring and Peritoneal Tunneling Technique: Tips and Tricks.

    PubMed

    Guan, Xiaoming; Ma, Yingchun; Gisseman, Jordan; Kleithermes, Christopher; Liu, Juan

    2017-01-01

    To demonstrate the tips and tricks of a simpler technique for single-site sacrocolpopexy using barbed suture anchoring and retroperitoneal tunneling to make the procedure more efficient and reproducible. Step-by-step description of surgical tutorial using a narrated video (Canadian Task Force classification III). Academic tertiary care hospital. Patient with Stage III uterine prolapse. Sacrocolpopexy is increasing utilized since the FDA warning about complications of vaginal mesh surgery. It is the gold standard for repair of apical prolapse. However, there is great variation in the sacrocolpopexy procedure techniques and they have not been standardized. Traditional single-site laparoscopic sacrocolpopexy is very challenging as the procedure time is long and suturing is difficult. The advantages of suturing with wristed needle drivers in robotic single-site surgery simplify this complex procedure. Furthermore, using barbed suture anchoring and peritoneal tunneling technique potentially decreases the surgeon's learning curve and makes the procedure reproducible. In this video, we demonstrate a supracervial hysterectomy with a stepwise explanation of the correct technique for performing a robotic single incision sacrocolpopexy. Sacrocolpopexy is increasing used since the US Food and Drug Administration warning about complications of vaginal mesh surgery. It is the gold standard for repair of apical prolapse. However, a great variation exists in the sacrocolpopexy procedure techniques that need to be standardized. Traditional single-site laparoscopic sacrocolpopexy is very challenging because the procedure time is long and suturing is difficult. The advantages of suturing with wristed needle drivers in robotic single-site surgery simplify this complex procedure. Furthermore, using the barbed suture anchoring and peritoneal tunneling technique potentially decreases the surgeon's learning curve and makes the procedure reproducible. In this video, we demonstrate a

  9. Bone-anchored hearing aid (Baha) in patients with Treacher Collins syndrome: tips and pitfalls.

    PubMed

    Marsella, Pasquale; Scorpecci, Alessandro; Pacifico, Concettina; Tieri, Luigi

    2011-10-01

    Treacher Collins syndrome, also known as mandibulofacial dysostosis, is an autosomal dominant disorder of the cranio-facial morphogenesis affecting 1 of 50,000 live newborns. Most children with this disease present with bilateral, severe conductive hearing loss due to bilateral aural atresia. Auditory rehabilitation of these children can be effectively carried out with bone-anchored hearing aids (Baha). The aim of this retrospective study is to review the "Bambino Gesù" Children's Hospital's experience with Baha in Treacher Collins patients, highlighting the tips and pitfalls of Baha surgery in this particular population. The clinical charts were reviewed of all children with a Treacher Collins syndrome diagnosis receiving a Baha in the "Bambino Gesù" Children's Hospital from January 1995 to January 2010. Data were collected concerning patients' anagraphics and medical history, comorbidities, surgical technique, complications and functional outcome. 23 Treacher Collins children were included. A two-stage surgery was adopted in 51% (n=12) cases, while a one-stage approach was chosen in 49% (n=11). 2 children underwent 1st stage surgery as they were younger than 5. There were neither cases of osseointegration failure, nor cases of traumatic implant loss. Overall, the local complication rate was not different in the one-stage and in the two-stage group. The functional gain was significantly better with the Baha than with the conventional bone-conduction hearing aids (p<0.0002). There was no difference in terms of functional outcome between the 7 patients receiving Baha at an age younger than 5 years and the rest (p=0.23). Baha can provide effective auditory rehabilitation for children with Treacher Collins syndrome, as long as it is performed in a tertiary care center where a multidisciplinary approach to the frequent comorbidities is possible. The main challenge of Baha surgery in this population is the poor or irregular thickness of the patient's calvarial bone

  10. Tip Cells Act as Dynamic Cellular Anchors in the Morphogenesis of Looped Renal Tubules in Drosophila

    PubMed Central

    Weavers, Helen; Skaer, Helen

    2013-01-01

    Summary Tissue morphogenesis involves both the sculpting of tissue shape and the positioning of tissues relative to one another in the body. Using the renal tubules of Drosophila, we show that a specific distal tubule cell regulates both tissue architecture and position in the body cavity. Focusing on the anterior tubules, we demonstrate that tip cells make transient contacts with alary muscles at abdominal segment boundaries, moving progressively forward as convergent extension movements lengthen the tubule. Tip cell anchorage antagonizes forward-directed, TGF-β-guided tubule elongation, thereby ensuring the looped morphology characteristic of renal tubules from worms to humans. Distinctive tip cell exploratory behavior, adhesion, and basement membrane clearing underlie target recognition and dynamic interactions. Defects in these features obliterate tip cell anchorage, producing misshapen and misplaced tubules with impaired physiological function. PMID:24229645

  11. Localization of Cacna1s to ON Bipolar Dendritic Tips Requires mGluR6-Related Cascade Elements

    PubMed Central

    Tummala, Shanti R.; Neinstein, Adam; Fina, Marie E.; Dhingra, Anuradha; Vardi, Noga

    2014-01-01

    Purpose. L-type voltage gated calcium channels in retina localize primarily at the presynaptic active zones of photoreceptors and bipolar cells where they modulate glutamate release. However, the pore forming subunit Cacna1s of certain L-type channels is also expressed postsynaptically at the tips of ON bipolar cell dendrites where it colocalizes with mGluR6, but has an unknown function. At these dendritic tips, the components of the mGluR6 signaling cascade cluster together in a macromolecular complex, and each one's localization often depends on that of the others. Thus, we explored if Cacna1s is part of the mGluR6 complex. Methods. We determined Cacna1s expression by PCR using an ON bipolar library, by Western blotting, and by standard immunohistochemistry. Results. The PCR amplification confirmed expression of the transcript in ON bipolar cells, and Western blotting showed the expected bands. Immunostaining for Cacna1s was stronger in the dendritic tips of rod bipolar cells than in those of ON cone bipolar cells. This staining severely decreased in mice missing various mGluR6 cascade elements (Grm6−/−, Gnao1−/−, Gnb3−/−, Gng13−/−, and Trpm1−/−). During development, the ratio of the number of Cacna1s puncta to the number of presynaptic ribbons followed a sigmoidal pattern, rising rapidly from P13 to P17. The mGluR6 expression preceded that of Cacna1s and RGS11. Conclusions. Our results show that the localization and stability of Cacna1s depend on the expression of mGluR6 and its cascade components, and they suggest that Cacna1s is part of the mGluR6 complex. We hypothesize that Cacna1s contributes to light adaptation by permeating calcium. PMID:24519419

  12. AFM-induced amine deprotection: triggering localized bond cleavage by application of tip/substrate voltage bias for the surface self-assembly of nanosized dendritic objects.

    PubMed

    Fresco, Zachary M; Suez, Itai; Backer, Scott A; Fréchet, Jean M J

    2004-07-14

    An alpha,alpha-dimethyl-3,5-dimethoxybenzyloxycarbonyl (DDZ)-protected amine monolayer can be selectively deprotected by the application of a voltage bias from a conducting AFM tip to afford localized nanoscale patterns that can be visualized by self-assembly of dendritic molecular objects with terminal carboxylic acid groups and different aspect ratios.

  13. Dendrite

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Researchers have found that as melted metals and alloys (combinations of metals) solidify, they can form with different arrangements of atoms, called microstructures. These microstructures depend on the shape of the interface (boundary) between the melted metal and the solid crystal it is forming. There are generally three shapes that the interface can take: planar, or flat; cellular, which looks like the cells of a beehive; and dendritic, which resembles tiny fir trees. Convection at this interface can affect the interface shape and hide the other phenomena (physical events). To reduce the effects of convection, researchers conduct experiments that examine and control conditions at the interface in microgravity. Microgravity also helps in the study of alloys composed of two metals that do not mix. On Earth, the liquid mixtures of these alloys settle into different layers due to gravity. In microgravity, the liquid metals do not settle, and a solid more uniform mixture of both metals can be formed.

  14. LRIT3 is essential to localize TRPM1 to the dendritic tips of depolarizing bipolar cells and may play a role in cone synapse formation

    PubMed Central

    Neuillé, Marion; Morgans, Catherine W.; Cao, Yan; Orhan, Elise; Michiels, Christelle; Sahel, José-Alain; Audo, Isabelle; Duvoisin, Robert M.; Martemyanov, Kirill A.; Zeitz, Christina

    2016-01-01

    Mutations in LRIT3 lead to complete congenital stationary night blindness (cCSNB). The exact role of LRIT3 in ON-bipolar cell signaling cascade remains to be elucidated. Recently, we have characterized a novel mouse model lacking Lrit3 (no b-wave 6, (Lrit3nob6/nob6)), which displays similar abnormalities as patients with cCSNB with LRIT3 mutations. Here we compare the localization of components of the ON-bipolar cell signaling cascade in wild-type and Lrit3nob6/nob6 retinal sections by immunofluorescence confocal microscopy. An anti-LRIT3 antibody was generated. Immunofluorescent staining of LRIT3 in wild-type mice revealed a specific punctate labeling in the outer plexiform layer (OPL), which was absent in Lrit3nob6/nob6 mice. LRIT3 did not colocalize with ribeye or calbindin but colocalized with mGluR6. TRPM1 staining was severely decreased at the dendritic tips of all depolarizing bipolar cells in Lrit3nob6/nob6 mice. mGluR6, GPR179, RGS7, RGS11 and Gβ5 immunofluorescence was absent at the dendritic tips of cone ON-bipolar cells in Lrit3nob6/nob6 mice, while it was present at the dendritic tips of rod bipolar cells. Furthermore, PNA labeling was severely reduced in the OPL in Lrit3nob6/nob6 mice. This study confirmed the localization of LRIT3 at the dendritic tips of depolarizing bipolar cells in mouse retina and demonstrated the dependence of TRPM1 localization on the presence of LRIT3. Since tested components of the ON-bipolar cell signaling cascade and PNA revealed disrupted localization, an additional function of LRIT3 in cone synapse formation is suggested. These results point to a possibly different regulation of the mGluR6 signaling cascade between rod and cone ON-bipolar cells. PMID:25997951

  15. The accuracy of a 2D and 3D dendritic tip scaling parameter in predicting the columnar to equiaxed transition (CET)

    NASA Astrophysics Data System (ADS)

    Seredyński, M.; Rebow, M.; Banaszek, J.

    2016-09-01

    The dendrite tip kinetics model accuracy relies on the reliability of the stability constant used, which is usually experimentally determined for 3D situations and applied to 2D models. The paper reports authors' attempts to cure the situation by deriving 2D dendritic tip scaling parameter for aluminium-based alloy: Al-4wt%Cu. The obtained parameter is then incorporated into the KGT dendritic growth model in order to compare it with the original 3D KGT counterpart and to derive two-dimensional and three-dimensional versions of the modified Hunt's analytical model for the columnar-to-equiaxed transition (CET). The conclusions drawn from the above analysis are further confirmed through numerical calculations of the two cases of Al-4wt%Cu metallic alloy solidification using the front tracking technique. Results, including the porous zone-under-cooled liquid front position, the calculated solutal under-cooling and a new predictor of the relative tendency to form an equiaxed zone, are shown, compared and discussed two numerical cases. The necessity to calculate sufficiently precise values of the tip scaling parameter in 2D and 3D is stressed.

  16. A protein complex containing Epo1p anchors the cortical endoplasmic reticulum to the yeast bud tip

    PubMed Central

    Neller, Joachim; Dünkler, Alexander; Rösler, Reinhild

    2015-01-01

    The cortical endoplasmic reticulum (cER) of yeast underlies the plasma membrane (PM) at specific contact sites to enable a direct transfer of information and material between both organelles. During budding, directed movement of cER to the young bud followed by subsequent anchorage at its tip ensures the faithful inheritance of this organelle. The ER membrane protein Scs2p tethers the cER to the PM and to the bud tip through so far unknown receptors. We characterize Epo1p as a novel member of the polarisome that interacts with Scs2p exclusively at the cell tip during bud growth and show that Epo1p binds simultaneously to the Cdc42p guanosine triphosphatase–activating protein Bem3p. Deletion of EPO1 or deletion of BEM3 in a polarisome-deficient strain reduces the amount of cER at the tip. This analysis therefore identifies Epo1p as a novel and important component of the polarisome that promotes cER tethering at sites of polarized growth. PMID:25547157

  17. Selection criterion for the growing dendritic tip in a non-isothermal binary system under forced convective flow

    NASA Astrophysics Data System (ADS)

    Alexandrov, D. V.; Galenko, P. K.; Herlach, D. M.

    2010-07-01

    A free dendrite growth during solidification into external forced flow is analyzed using a sharp interface model. A criterion for selection of the stable growth mode is derived for the axisymmetric dendrite growing into non-isothermal binary system under convective flow. The criterion obtained rallies analytic results for dendrite growth under forced convection in a pure system [Ph. Bouissou, P. Pelce, Phys. Rev. A 40 (1989) 6673] and dendrite growth in a stagnant binary system [M. Ben Amar, P. Pelce, Phys. Rev. A 39 (1989) 4263].

  18. LRIT3 is essential to localize TRPM1 to the dendritic tips of depolarizing bipolar cells and may play a role in cone synapse formation.

    PubMed

    Neuillé, Marion; Morgans, Catherine W; Cao, Yan; Orhan, Elise; Michiels, Christelle; Sahel, José-Alain; Audo, Isabelle; Duvoisin, Robert M; Martemyanov, Kirill A; Zeitz, Christina

    2015-08-01

    Mutations in LRIT3 lead to complete congenital stationary night blindness (cCSNB). The exact role of LRIT3 in ON-bipolar cell signaling cascade remains to be elucidated. Recently, we have characterized a novel mouse model lacking Lrit3 [no b-wave 6, (Lrit3(nob6/nob6) )], which displays similar abnormalities to patients with cCSNB with LRIT3 mutations. Here we compare the localization of components of the ON-bipolar cell signaling cascade in wild-type and Lrit3(nob6/nob6) retinal sections by immunofluorescence confocal microscopy. An anti-LRIT3 antibody was generated. Immunofluorescent staining of LRIT3 in wild-type mice revealed a specific punctate labeling in the outer plexiform layer (OPL), which was absent in Lrit3(nob6/nob6) mice. LRIT3 did not co-localize with ribeye or calbindin but co-localized with mGluR6. TRPM1 staining was severely decreased at the dendritic tips of all depolarizing bipolar cells in Lrit3(nob6/nob6) mice. mGluR6, GPR179, RGS7, RGS11 and Gβ5 immunofluorescence was absent at the dendritic tips of cone ON-bipolar cells in Lrit3(nob6/nob6) mice, while it was present at the dendritic tips of rod bipolar cells. Furthermore, peanut agglutinin (PNA) labeling was severely reduced in the OPL in Lrit3(nob6/nob6) mice. This study confirmed the localization of LRIT3 at the dendritic tips of depolarizing bipolar cells in mouse retina and demonstrated the dependence of TRPM1 localization on the presence of LRIT3. As tested components of the ON-bipolar cell signaling cascade and PNA revealed disrupted localization, an additional function of LRIT3 in cone synapse formation is suggested. These results point to a possibly different regulation of the mGluR6 signaling cascade between rod and cone ON-bipolar cells.

  19. Influence of Electrolyte Modulus on the Local Current Density at a Dendrite Tip on a Lithium Metal Electrode

    SciTech Connect

    Harry, Katherine J.; Higa, Kenneth; Srinivasan, Venkat; Balsara, Nitash P.

    2016-08-10

    Understanding and controlling the electrochemical deposition of lithium is imperative for the safe use of rechargeable batteries with a lithium metal anode. Solid block copolymer electrolyte membranes are known to enhance the stability of lithium metal anodes by mechanically suppressing the formation of lithium protrusions during battery charging. Time-resolved hard X-ray microtomography was used to monitor the internal structure of a symmetric lithium-polymer cell during galvanostatic polarization. The microtomography images were used to determine the local rate of lithium deposition, i.e. local current density, in the vicinity of a lithium globule growing through the electrolyte. Measurements of electrolyte displacement enabled estimation of local stresses in the electrolyte. At early times, the current density was maximized at the globule tip, as expected from simple current distribution arguments. At later times, the current density was maximized at the globule perimeter. We show that this phenomenon is related to the local stress fields that arise as the electrolyte is deformed. The local current density, normalized for the radius of curvature, decreases with increasing compressive stresses at the lithium-polymer interface. To our knowledge, our study provides the first direct measurement showing the influence of local mechanical stresses on the deposition kinetics at lithium metal electrodes.

  20. Influence of Electrolyte Modulus on the Local Current Density at a Dendrite Tip on a Lithium Metal Electrode

    DOE PAGES

    Harry, Katherine J.; Higa, Kenneth; Srinivasan, Venkat; ...

    2016-08-10

    Understanding and controlling the electrochemical deposition of lithium is imperative for the safe use of rechargeable batteries with a lithium metal anode. Solid block copolymer electrolyte membranes are known to enhance the stability of lithium metal anodes by mechanically suppressing the formation of lithium protrusions during battery charging. Time-resolved hard X-ray microtomography was used to monitor the internal structure of a symmetric lithium-polymer cell during galvanostatic polarization. The microtomography images were used to determine the local rate of lithium deposition, i.e. local current density, in the vicinity of a lithium globule growing through the electrolyte. Measurements of electrolyte displacement enabledmore » estimation of local stresses in the electrolyte. At early times, the current density was maximized at the globule tip, as expected from simple current distribution arguments. At later times, the current density was maximized at the globule perimeter. We show that this phenomenon is related to the local stress fields that arise as the electrolyte is deformed. The local current density, normalized for the radius of curvature, decreases with increasing compressive stresses at the lithium-polymer interface. To our knowledge, our study provides the first direct measurement showing the influence of local mechanical stresses on the deposition kinetics at lithium metal electrodes.« less

  1. An earth anchor system: installation and design guide.

    Treesearch

    R.L. Copstead; D.D. Studier

    1990-01-01

    A system for anchoring the guylines and skylines of cable yarding equipment is presented. A description of three types of tipping plate anchors is given. Descriptions of the installation equipment and methods specific to each type are given. Procedures for determining the correct number of anchors to install are included, as are guidelines for installing the anchors so...

  2. Isothermal Dendritic Growth Experiment - PVA Dendrites

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The Isothermal Dendritic Growth Experiment (IDGE), flown on three Space Shuttle missions, is yielding new insights into virtually all industrially relevant metal and alloy forming operations. IDGE used transparent organic liquids that form dendrites (treelike structures) similar to those inside metal alloys. Comparing Earth-based and space-based dendrite growth velocity, tip size and shape provides a better understanding of the fundamentals of dentritic growth, including gravity's effects. Shalowgraphic images of pivalic acid (PVA) dendrites forming from the melt show the subtle but distinct effects of gravity-driven heat convection on dentritic growth. In orbit, the dendrite grows as its latent heat is liberated by heat conduction. This yields a blunt dendrite tip. On Earth, heat is carried away by both conduction and gravity-driven convection. This yields a sharper dendrite tip. In addition, under terrestrial conditions, the sidebranches growing in the direction of gravity are augmented as gravity helps carry heat out of the way of the growing sidebranches as opposed to microgravity conditions where no augmentation takes place. IDGE was developed by Rensselaer Polytechnic Institute and NASA/Glenn Research Center. Advanced follow-on experiments are being developed for flight on the International Space Station. Photo Credit: NASA/Glenn Research Center

  3. The N-terminus of IpaB provides a potential anchor to the Shigella type III secretion system tip complex protein IpaD

    PubMed Central

    Dickenson, Nicholas E.; Arizmendi, Olivia; Patil, Mrinalini K.; Toth, Ronald T.; Middaugh, C. Russell; Picking, William D.; Picking, Wendy L.

    2014-01-01

    The type III secretion system (T3SS) is an essential virulence factor for Shigella flexneri, providing a conduit through which host-altering effectors are injected directly into a host cell to promote uptake. The type III secretion apparatus (T3SA) is comprised of a basal body, external needle, and regulatory tip complex. The nascent needle is a polymer of MxiH capped by a pentamer of invasion plasmid antigen D (IpaD). Exposure to bile salts (e.g. deoxycholate) causes a conformational change in IpaD and promotes recruitment of IpaB to the needle tip. It has been proposed that IpaB senses contact with host cell membranes, recruiting IpaC and inducing full secretion of T3SS effectors. While the steps of T3SA maturation and their external triggers have been identified, details of specific protein interactions and mechanisms have remained difficult to study due to the hydrophobic nature of the IpaB and IpaC translocator proteins. Here we explored the ability for a series of soluble N-terminal IpaB peptides to interact with IpaD. We found that DOC is required for the interaction and that a region of IpaB between residues 11–27 is required for maximum binding, which was confirmed in vivo. Furthermore, intramolecular FRET measurements indicated that movement of the IpaD distal domain away from the protein core accompanied the binding of IpaB11-226. Together these new findings provide important new insight into the interactions and potential mechanisms that define the maturation of the Shigella T3SA needle tip complex and provide a foundation for further studies probing T3SS activation. PMID:24236510

  4. Free dendritic growth

    NASA Technical Reports Server (NTRS)

    Glicksman, M. E.

    1984-01-01

    Free dendritic growth refers to the unconstrained development of crystals within a supercooled melt, which is the classical 'dendrite problem'. Great strides have been taken in recent years in both the theoretical understanding of dendritic growth and its experimental status. The development of this field will be sketched, showing that transport theory and interfacial thermodynamics (capillarity theory) were sufficient ingredients to develop a truly predictive model of dendrite formation. The convenient, but incorrect, notion of 'maximum velocity' was used for many years to estimate the behavior of dendritic transformations until supplanted by modern dynamic stability theory. The proper combinations of transport theory and morphological stability seem to able to predict the salient aspects of dendritic growth, especially in the neighborhood of the tip. The overall development of cast microstructures, such as equiaxed zone formation, rapidly solidified microstructures, etc., also seems to contain additional non-deterministic features which lie outside the current theories discussed here.

  5. Free dendritic growth

    NASA Technical Reports Server (NTRS)

    Glicksman, M. E.

    1984-01-01

    Free dendritic growth refers to the unconstrained development of crystals within a supercooled melt, which is the classical 'dendrite problem'. Great strides have been taken in recent years in both the theoretical understanding of dendritic growth and its experimental status. The development of this field will be sketched, showing that transport theory and interfacial thermodynamics (capillarity theory) were sufficient ingredients to develop a truly predictive model of dendrite formation. The convenient, but incorrect, notion of 'maximum velocity' was used for many years to estimate the behavior of dendritic transformations until supplanted by modern dynamic stability theory. The proper combinations of transport theory and morphological stability seem to able to predict the salient aspects of dendritic growth, especially in the neighborhood of the tip. The overall development of cast microstructures, such as equiaxed zone formation, rapidly solidified microstructures, etc., also seems to contain additional non-deterministic features which lie outside the current theories discussed here.

  6. Transport Processes in Dendritic Crystallization

    NASA Technical Reports Server (NTRS)

    Glicksman, M. E.

    1984-01-01

    Free dentritic growth refers to the unconstrained development of crystals within a supercooled melt, which is the classical dendrite problem. The development of theoretical understanding of dendritic growth and its experimental status is sketched showing that transport theory and interfacial thermodynamics (capillarity theory) are insufficient ingredients to develop a truly predictive model of dendrite formation. The convenient, but incorrect, notion of maximum velocity was used for many years to estimate the behavior of dendritic transformations until supplanted by modern dynamic stability theory. The proper combinations of transport theory and morphological stability seem to be able to predict the salient aspects of dendritic growth, especially in the neighborhood of the tip.

  7. Anchor Modeling

    NASA Astrophysics Data System (ADS)

    Regardt, Olle; Rönnbäck, Lars; Bergholtz, Maria; Johannesson, Paul; Wohed, Petia

    Maintaining and evolving data warehouses is a complex, error prone, and time consuming activity. The main reason for this state of affairs is that the environment of a data warehouse is in constant change, while the warehouse itself needs to provide a stable and consistent interface to information spanning extended periods of time. In this paper, we propose a modeling technique for data warehousing, called anchor modeling, that offers non-destructive extensibility mechanisms, thereby enabling robust and flexible management of changes in source systems. A key benefit of anchor modeling is that changes in a data warehouse environment only require extensions, not modifications, to the data warehouse. This ensures that existing data warehouse applications will remain unaffected by the evolution of the data warehouse, i.e. existing views and functions will not have to be modified as a result of changes in the warehouse model.

  8. Equiaxed Dendritic Solidification Experiment (EDSE)

    NASA Technical Reports Server (NTRS)

    Beckermann, C.; Steinbach, I.; Karma, A.; deGroh, H. C., III

    1999-01-01

    The objective of the research is to quantitatively determine and understand the fundamental mechanisms that control the microstructural evolution during solidification of an assemblage of equiaxed dendritic crystals. A microgravity experiment will be conducted to obtain benchmark data on the transient growth and interaction of up to four equiaxed crystals of a pure and transparent metal analog (succinonitrile, SCN) under strictly diffusion dominated conditions. Of interest in the experiment are the transient evolution of the primary and secondary dendrite tip speeds, the dendrite morphology (i.e., tip radii, branch spacings, etc.) and solid fraction, the tip selection criterion, and the temperature field in the melt for a range of initial supercoolings and, thus, interaction "strengths" between the crystals. The experiment thus extends the microgravity measurements of Glicksman and coworkers for steady growth of a single dendrite [Isothermal Dendritic Growth Experiment (IDGE), first flown on USMP-2] to a case where growth transients are introduced due to thermal interactions between neighboring dendrites - a situation more close to actual casting conditions. Corresponding earth-based experiments will be conducted to ascertain the influence of melt convection. The experiments are supported by a variety of analytical models and numerical simulations. The data will primarily be used to develop and test theories of transient dendritic growth and the solidification of multiple interacting equiaxed crystals in a supercooled melt.

  9. Dendritic Growth Velocities in Microgravity

    NASA Technical Reports Server (NTRS)

    Glicksman, M. E.; Koss, M. B.; Winsa, E. A.

    1994-01-01

    We measured dendritic tip velocities in pure succinonitrile (SCN) in microgravity. using a sequence of telemetered binary images sent to Earth from the Space Shuttle Columbia (STS-62). Growth velocities were measured as a function of the supercooling over the range 0.05-1.5 K. Microgravity observations show that buoyancy-induced convection alters the growth kinetics of SCN dendrites at supercooling as high as 1.3 K. Also, the dendrite velocity data measured under microgravity agree well with the Ivantsov paraboloidal diffusion solution when coupled to a scaling constant of sigma(sup *) = 0.0157.

  10. Dendritic Growth Velocities in Microgravity

    NASA Technical Reports Server (NTRS)

    Glicksman, M. E.; Koss, M. B.; Winsa, E. A.

    1994-01-01

    We measured dendritic tip velocities in pure succinonitrile (SCN) in microgravity. using a sequence of telemetered binary images sent to Earth from the Space Shuttle Columbia (STS-62). Growth velocities were measured as a function of the supercooling over the range 0.05-1.5 K. Microgravity observations show that buoyancy-induced convection alters the growth kinetics of SCN dendrites at supercooling as high as 1.3 K. Also, the dendrite velocity data measured under microgravity agree well with the Ivantsov paraboloidal diffusion solution when coupled to a scaling constant of sigma(sup *) = 0.0157.

  11. Dendrite characteristics in directionally solidified Pb-8 pct Au and Pb-3 pct Pd alloys

    NASA Technical Reports Server (NTRS)

    Tewari, S. N.

    1986-01-01

    The dendritic microstructure and solute compression profiles for Pb-8 pct Au and Pb-3 pct Pd alloy samples are examined. Two groups of models, the minimum undercooled dendrite tip model of Burden and Hunt (1974) and Laxmanan (1974, 1984) and marginal stability at the dendrite tip models of Trivedi (1980) and Laxmanan (1974) are used to predict growth behavior of the alloy samples. The experimentally observed dendrite tip radius, primary arm spacing, and liquid composition at the dendrite tip are compared with theoretical predictions. It is observed that the modified minimum undercooling dendrite tip model and both of the marginal stability models accurately predict dendritic behavior. It is concluded that quantitative comparison of the primary arm spacing measurements can not form the basis for distinguishing among the various dendrite growth models in a positive temperature gradient.

  12. Equiaxed Dendritic Solidification Experiment (EDSE)

    NASA Technical Reports Server (NTRS)

    Beckermann, C.; Karma, A.; Steinbach, I.; deGroh, H. C., III

    2001-01-01

    The objective of the research is to quantitatively determine and understand the fundamental mechanisms that control the microstructural evolution during equiaxed dendritic solidification. A microgravity experiment will be conducted to obtain benchmark data on the transient growth and interaction of up to four equiaxed crystals of a pure and transparent metal analog (succinonitrile, SCN) under strictly diffusion-dominated conditions. Of interest in the experiment are the transient evolution of the primary and secondary dendrite tip speeds, the dendrite morphology and solid fraction, the tip selection criterion, and the temperature field in the melt for a range of interaction "strengths" between the crystals. The experiment extends the microgravity measurements of Glicksman and co-workers isothermal dendritic growth experiment (IDGE) for steady growth of a single dendrite to a case where growth transients are introduced due to thermal interactions between neighboring dendrites - a situation closer to actual casting conditions. Corresponding Earth-based experiments will be conducted to ascertain the influence of melt convection. The experiments are supported by a variety of analytical models and numerical simulations. The data will be used to develop and test theories of transient dendritic growth and the solidification of multiple interacting equiaxed crystals in a supercooled melt.

  13. Isothermal Dendritic Growth Experiment - SCN Dendrites

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Isothermal Dendritic Growth Experiment (IDGE), flown on three Space Shuttle missions, is yielding new insights into virtually all industrially relevant metal and alloy forming operations. IDGE used transparent organic liquids that form dendrites (treelike structures) similar to the crystals that form inside metal alloys. Comparing Earth-based and space-based dentrite growth velocity, tip size and shape provid a better understanding of the fundamentals of dentritic growth, including gravity's effects. These shadowgraphic images show succinonitrile (SCN) dentrites growing in a melt (liquid). The space-grown crystals also have cleaner, better defined sidebranches. IDGE was developed by Rensselaer Polytechnic Institude (RPI) and NASA/ Glenn Research Center(GRC). Advanced follow-on experiments are being developed for flight on the International Space Station. Photo gredit: NASA/Glenn Research Center

  14. Ultrasonic/Sonic Anchor

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Sherrit, Stewart

    2009-01-01

    The ultrasonic/sonic anchor (U/S anchor) is an anchoring device that drills a hole for itself in rock, concrete, or other similar material. The U/S anchor is a recent addition to a series of related devices, the first of which were reported in "Ultrasonic/Sonic Drill/Corers With Integrated Sensors"

  15. Microgravity Drill and Anchor System

    NASA Technical Reports Server (NTRS)

    Parness, Aaron; Frost, Matthew A.; King, Jonathan P.

    2013-01-01

    microspine toes that independently find holes and ledges on a rock to create an anchor. Once the system is anchored, a linear translation mechanism moves the drill axially into the surface while maintaining the proper WOB. The linear translation mechanism is composed of a ball screw and stepper motor that can translate a carriage with high precision and applied load. The carriage slides along rails using self-aligning linear bearings that correct any axial misalignment caused by bending and torsion. The carriage then compresses a series of springs that simultaneously transmit the load to the drill along the bit axis and act as a suspension that compensates for the vibration caused by percussive drilling. The drill is a compacted, modified version of an off-the-shelf rotary percussive drill, which uses a custom carbide-tipped coring bit. By using rotary percussive drilling, the drill time is greatly reduced. The percussive action fractures the rock debris, which is removed during rotation. The final result is a 0.75-in. (.1.9- cm) diameter hole and a preserved 0.5- in. (.1.3-cm) diameter rock core. This work extends microspine technology, making it applicable to astronaut missions to asteroids and a host of robotic sampling concepts. At the time of this reporting, it is the first instrument to be demonstrated using microspine anchors, and is the first self-contained drill/anchor system to be demonstrated that is capable of drilling in inverted configurations and would be capable of drilling in microgravity.

  16. Pattern selection in dendritic solidification

    NASA Technical Reports Server (NTRS)

    Ben-Jacob, E.; Goldenfeld, N.; Kotliar, B. G.; Langer, J. S.

    1984-01-01

    It is shown that the dynamically selected velocity and tip radius of dendrites in the boundary-layer model of solidification have the special values which permit the existence of steady-state needle-crystal solutions. This result, in conjunction with considerations of stability, provides new insight concerning the validity of the marginal-stability hypothesis.

  17. Progress in Modeling Nonlinear Dendritic Evolution in Two and Three Dimensions, and Its Mathematical Justification

    NASA Technical Reports Server (NTRS)

    Tanveer, S.; Foster, M. R.

    2002-01-01

    We report progress in three areas of investigation related to dendritic crystal growth. Those items include: 1. Selection of tip features dendritic crystal growth; 2) Investigation of nonlinear evolution for two-sided model; and 3) Rigorous mathematical justification.

  18. Dendrite preventing separator for secondary lithium batteries

    NASA Technical Reports Server (NTRS)

    Shen, David H. (Inventor); Surampudi, Subbarao (Inventor); Huang, Chen-Kuo (Inventor); Halpert, Gerald (Inventor)

    1993-01-01

    Dendrites are prevented from shorting a secondary lithium battery by use of a first porous separator, such as porous polypropylene, adjacent to the lithium anode that is unreactive with lithium and a second porous fluoropolymer separator between the cathode and the first separator, such as polytetrafluoroethylene, that is reactive with lithium. As the tip of a lithium dendrite contacts the second separator, an exothermic reaction occurs locally between the lithium dendrite and the fluoropolymer separator. This results in the prevention of the dendrite propagation to the cathode.

  19. Dendrite preventing separator for secondary lithium batteries

    NASA Technical Reports Server (NTRS)

    Shen, David H. (Inventor); Surampudi, Subbarao (Inventor); Huang, Chen-Kuo (Inventor); Halpert, Gerald (Inventor)

    1995-01-01

    Dendrites are prevented from shorting a secondary lithium battery by use of a first porous separator such as porous polypropylene adjacent the lithium anode that is unreactive with lithium and a second porous fluoropolymer separator between the cathode and the first separator such as polytetrafluoroethylene that is reactive with lithium. As the tip of a lithium dendrite contacts the second separator, an exothermic reaction occurs locally between the lithium dendrite and the fluoropolymer separator. This results in the prevention of the dendrite propagation to the cathode.

  20. Effect of Solute Diffusion on Dendrite Growth in the Molten Pool of Al-Cu Alloy

    NASA Astrophysics Data System (ADS)

    Zhan, Xiaohong; Gu, Cheng; Liu, Yun; Wei, Yanhong

    2017-10-01

    A cellular automaton (CA)-finite difference model is developed to simulate dendrite growth and solute diffusion during solidification process in the molten pool of Al-Cu alloy. In order to explain the interaction between the dendritic growth and solute distribution, a series of CA simulations with different solute diffusion velocity coefficients are carried out. It is concluded that the solute concentration increases with dendrite growing and solute accumulation in the dendrite tip. Converged value of the dendrite tip growth velocity is about 480 μm/s if the mesh size is refined to 2 μm or less. Growth of the primary dendrite and the secondary dendrite is mainly influenced by solute diffusion at the dendrite tips. And growth of secondary and tertiary dendrites is mainly influenced by solute diffusion at interdendrite.

  1. Dendritic solidification. III - Some further refinements to the model for dendritic growth under an imposed thermal gradient

    NASA Technical Reports Server (NTRS)

    Laxmanan, V.

    1985-01-01

    Some further refinements to a simple model for dendritic solidification in a binary alloy melt under an imposed positive thermal gradient are presented. Two new expressions for the dendrite tip undercooling have been obtained and shown to yield a limiting value of Delta T sub 0 and very small growth rates. Here Delta T sub 0 is the equilibrium solidification range of the alloy. At very large growth rates, all three tip undercooling expressions reach the same limiting value depending on the value of a dimensionless parameter lambda which is related to the effective diffusion distance ahead of the dendrite tip. The predicted tip undercoolings are, however, somewhat lower at intermediate growth rates. An improved calculation for the solute buildup at the dendrite tip due to curvature effects is also included.

  2. IDGE - A test of dendritic growth theory using space flight

    NASA Technical Reports Server (NTRS)

    Glicksman, M. E.; Koss, M. B.; Hahn, R. C.; Herbach, B. A.; Winsa, E. A.

    1993-01-01

    The isothermal Dendritic Growth Experiment (IDGE), to be performed on three of the United States Microgravity Payload (USMP) flights, starting with USMP-2, is designed to provide microgravity data on dendritic growth for a critical test of theory. Ground based test data using succinonitrile (SCN), from both a flight growth chamber and a laboratory growth chamber, are compared to theoretical calculations of dendritic tip velocities and radii. The comparison shows that the data from the flight chamber are consistent with the historical data and that dendritic growth in a microgravity environment should exhibit significant differences from the dendritic growth of SCN at g sub 0.

  3. Anchors for Education Reforms

    ERIC Educational Resources Information Center

    Alok, Kumar

    2012-01-01

    Education reforms, considering their significance, deserve better methods than mere "trial and error." This article conceptualizes a network of six anchors for education reforms: education policy, education system, curriculum, pedagogy, assessment, and teacher education. It establishes the futility to reform anchors in isolation and…

  4. Anchors for Education Reforms

    ERIC Educational Resources Information Center

    Alok, Kumar

    2012-01-01

    Education reforms, considering their significance, deserve better methods than mere "trial and error." This article conceptualizes a network of six anchors for education reforms: education policy, education system, curriculum, pedagogy, assessment, and teacher education. It establishes the futility to reform anchors in isolation and…

  5. Dendritic gold nanowire growth observed in liquid with transmission electron microscopy.

    PubMed

    Kraus, Tobias; de Jonge, Niels

    2013-07-02

    The growth of nanoscale gold dendrites was studied in situ in a thin liquid film with transmission electron microscopy (TEM) using a liquid cell with silicon nitride (SiN) windows. Gold nanoparticle seeds were covered by a thin liquid layer containing precursor solution. Dendrite nucleation was induced by the electron beam leading to an initial burst of growth. The growth then settled at tip velocities between 0.1 and 2.0 nm/s for different dendrites. Tip velocities fluctuated as different dendrite geometries grew from the tips. Those dendrites showing granularities in their structure experienced the largest growth speed. Comparison of the observed velocities with diffusion-limited growth rates suggests that dendrite growth in thin films at this scale is limited by diffusion. The described method may find application in research on the mechanisms behind dendrite growth and also to study other types of anisotropic growth of nanomaterials driven by crystal and twin geometries.

  6. Dendrite inhibitor

    DOEpatents

    Miller, William E.

    1989-01-01

    An apparatus for removing dendrites or other crystalline matter from the surface of a liquid in a matter transport process, and an electrolytic cell including such an apparatus. A notch may be provided to allow continuous exposure of the liquid surface, and a bore may be further provided to permit access to the liquid.

  7. Dendrite inhibitor

    DOEpatents

    Miller, W.E.

    1988-06-07

    An apparatus for removing dendrites or other crystalline matter from the surface of a liquid in a matter transport process, and an electrolytic cell including such an apparatus. A notch may be provided to allow continuous exposure of the liquid surface, and a bore may be further provided to permit access to the liquid. 2 figs.

  8. Anchor Trial Launch

    Cancer.gov

    NCI has launched a multicenter phase III clinical trial called the ANCHOR Study -- Anal Cancer HSIL (High-grade Squamous Intraepithelial Lesion) Outcomes Research Study -- to determine if treatment of HSIL in HIV-infected individuals can prevent anal canc

  9. Dendritic solidification. I - Analysis of current theories and models. II - A model for dendritic growth under an imposed thermal gradient

    NASA Technical Reports Server (NTRS)

    Laxmanan, V.

    1985-01-01

    A critical review of the present dendritic growth theories and models is presented. Mathematically rigorous solutions to dendritic growth are found to rely on an ad hoc assumption that dendrites grow at the maximum possible growth rate. This hypothesis is found to be in error and is replaced by stability criteria which consider the conditions under which a dendrite tip advances in a stable fashion in a liquid. The important elements of a satisfactory model for dendritic solidification are summarized and a theoretically consistent model for dendritic growth under an imposed thermal gradient is proposed and described. The model is based on the modification of an analysis due to Burden and Hunt (1974) and predicts correctly in all respects, the transition from a dendritic to a planar interface at both very low and very large growth rates.

  10. TIP list

    SciTech Connect

    Ludwig, M E

    2006-06-22

    Subcontractors and vendors providing services, including the installation of purchased goods, are required to complete a TIP List. This list does not include every Environment, Safety, and Health (ES&H) related concern at LLNL. It is intended to highlight major concerns common to most on-site service activities.

  11. Technology Tips

    ERIC Educational Resources Information Center

    Stohl, Hollylynne; Harper, Suzanne R.

    2004-01-01

    Some of the graphing capabilities of The Geometer's Sketchpad (GSP) in the "Technology Tips" are introduced. The new graphing features of GSP allow teachers to implement the software not only in geometry classrooms but also into their algebra, precalculus and calculus classes.

  12. Technology Tips

    ERIC Educational Resources Information Center

    Santos-Trigo, Manuel

    2004-01-01

    A dynamic program for geometry called Cabri Geometry II is used to examine properties of figures like triangles and make connections with other mathematical ideas like ellipse. The technology tip includes directions for creating such a problem with technology and suggestions for exploring it.

  13. Technology Tips

    ERIC Educational Resources Information Center

    Santos-Trigo, Manuel

    2004-01-01

    A dynamic program for geometry called Cabri Geometry II is used to examine properties of figures like triangles and make connections with other mathematical ideas like ellipse. The technology tip includes directions for creating such a problem with technology and suggestions for exploring it.

  14. The anchor integration model: A descriptive model of anchoring effects.

    PubMed

    Turner, Brandon M; Schley, Dan R

    2016-11-01

    Few experimental effects in the psychology of judgment and decision making have been studied as meticulously as the anchoring effect. Although the existing literature provides considerable insight into the psychological processes underlying anchoring effects, extant theories up to this point have only generated qualitative predictions. While these theories have been productive in advancing our understanding of the underlying anchoring process, they leave much to be desired in the interpretation of specific anchoring effects. In this article, we introduce the Anchor Integration Model (AIM) as a descriptive tool for the measurement and quantification of anchoring effects. We develop two versions the model: one suitable for assessing between-participant anchoring effects, and another for assessing individual differences in anchoring effects. We then fit each model to data from two experiments, and demonstrate the model's utility in describing anchoring effects. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Dendritic growth with the six-fold symmetry: Theoretical predictions and experimental verification

    NASA Astrophysics Data System (ADS)

    Alexandrov, D. V.; Galenko, P. K.

    2017-09-01

    A free dendrite growing in a pure substance is considered with the interfacial effect of anisotropy and convective flow. A stable mode of dendritic growth with the six-fold crystal symmetry is studied using the solvability theory. We demonstrate that the obtained selection criterion for a stable mode of dendritic growth is a function of surface energy stiffness, arbitrary values of Péclet numbers and convective flow intensity. To predict the dendrite tip velocity V and its tip radius R a model of dendrite growth with the six-fold symmetry is formulated. We show that the model equations can be reduced to the growth kinetics with the low Péclet numbers, which exhibit the explicit relationships ;tip velocity - undercooling;. The model predictions are compared with experimental data on ice dendrites grown from pure undercooled water on board of the International Space Station (under microgravitational conditions, μg) and on the Ground (under terrestrial conditions, 1 g).

  16. Ternary eutectic dendrites: Pattern formation and scaling properties.

    PubMed

    Rátkai, László; Szállás, Attila; Pusztai, Tamás; Mohri, Tetsuo; Gránásy, László

    2015-04-21

    Extending previous work [Pusztai et al., Phys. Rev. E 87, 032401 (2013)], we have studied the formation of eutectic dendrites in a model ternary system within the framework of the phase-field theory. We have mapped out the domain in which two-phase dendritic structures grow. With increasing pulling velocity, the following sequence of growth morphologies is observed: flat front lamellae → eutectic colonies → eutectic dendritesdendrites with target pattern → partitionless dendrites → partitionless flat front. We confirm that the two-phase and one-phase dendrites have similar forms and display a similar scaling of the dendrite tip radius with the interface free energy. It is also found that the possible eutectic patterns include the target pattern, and single- and multiarm spirals, of which the thermal fluctuations choose. The most probable number of spiral arms increases with increasing tip radius and with decreasing kinetic anisotropy. Our numerical simulations confirm that in agreement with the assumptions of a recent analysis of two-phase dendrites [Akamatsu et al., Phys. Rev. Lett. 112, 105502 (2014)], the Jackson-Hunt scaling of the eutectic wavelength with pulling velocity is obeyed in the parameter domain explored, and that the natural eutectic wavelength is proportional to the tip radius of the two-phase dendrites. Finally, we find that it is very difficult/virtually impossible to form spiraling two-phase dendrites without anisotropy, an observation that seems to contradict the expectations of Akamatsu et al. Yet, it cannot be excluded that in isotropic systems, two-phase dendrites are rare events difficult to observe in simulations.

  17. Ternary eutectic dendrites: Pattern formation and scaling properties

    SciTech Connect

    Rátkai, László; Szállás, Attila; Pusztai, Tamás; Mohri, Tetsuo; Gránásy, László

    2015-04-21

    Extending previous work [Pusztai et al., Phys. Rev. E 87, 032401 (2013)], we have studied the formation of eutectic dendrites in a model ternary system within the framework of the phase-field theory. We have mapped out the domain in which two-phase dendritic structures grow. With increasing pulling velocity, the following sequence of growth morphologies is observed: flat front lamellae → eutectic colonies → eutectic dendritesdendrites with target pattern → partitionless dendrites → partitionless flat front. We confirm that the two-phase and one-phase dendrites have similar forms and display a similar scaling of the dendrite tip radius with the interface free energy. It is also found that the possible eutectic patterns include the target pattern, and single- and multiarm spirals, of which the thermal fluctuations choose. The most probable number of spiral arms increases with increasing tip radius and with decreasing kinetic anisotropy. Our numerical simulations confirm that in agreement with the assumptions of a recent analysis of two-phase dendrites [Akamatsu et al., Phys. Rev. Lett. 112, 105502 (2014)], the Jackson-Hunt scaling of the eutectic wavelength with pulling velocity is obeyed in the parameter domain explored, and that the natural eutectic wavelength is proportional to the tip radius of the two-phase dendrites. Finally, we find that it is very difficult/virtually impossible to form spiraling two-phase dendrites without anisotropy, an observation that seems to contradict the expectations of Akamatsu et al. Yet, it cannot be excluded that in isotropic systems, two-phase dendrites are rare events difficult to observe in simulations.

  18. Sensitivity analysis of dendritic growth kinetics in a Bridgman furnace front tracking model

    NASA Astrophysics Data System (ADS)

    Mooney, R. P.; McFadden, S.

    2016-03-01

    A directional solidification experiment of a Ti-Al-Nb-B-C alloy by power down method is simulated using a Bridgman furnace front tracking model. The effect of varying the dendritic growth parameters; C, the columnar dendrite growth coefficient, and n, the undercooling exponent, is investigated. A matrix of growth coefficients and undercooling exponents - at three levels each, based around a growth law for Ti-46wt.%Al - is applied in simulations, and the effect on columnar dendrite tip temperature, tip velocity, and tip temperature gradient is observed. The simulation results show that the dendrite tip velocity and temperature gradient at the tip are practically unaffected by the use of different growth parameters. However, the predicted columnar dendrite tip undercooling did vary to give the required dendrite tip velocity. This finding has implications for the analysis of microstructural transitions, such as the Columnar to Equiaxed Transition (CET). In conclusion, it is suggested that, for transient solidification conditions, a CET prediction criterion based on tip undercooling is preferable to one that uses growth velocity.

  19. Anchoring the Deficit of the Anchor Deficit: Dyslexia or Attention?

    ERIC Educational Resources Information Center

    Willburger, Edith; Landerl, Karin

    2010-01-01

    In the anchoring deficit hypothesis of dyslexia ("Trends Cogn. Sci.", 2007; 11: 458-465), it is proposed that perceptual problems arise from the lack of forming a perceptual anchor for repeatedly presented stimuli. A study designed to explicitly test the specificity of the anchoring deficit for dyslexia is presented. Four groups, representing all…

  20. Recycling Suture Limbs from Knotless Suture Anchors for Arthroscopic Shoulder Stabilization.

    PubMed

    Johnson, Timothy S; DiPompeo, Christine M; Ismaeli, Zahra C; Porter, Polly A; Nicholson, Shannon L; Johnson, David C

    2014-06-01

    Recurrent shoulder instability often leads to labral abnormality that requires surgical intervention that may require fixation with suture anchors. The proposed surgical technique allows the surgeon to achieve 2 points of fixation around the labrum and/or capsule with a single suture secured to the glenoid with a knotless anchor. Instead of cutting and discarding the residual suture limbs after anchor insertion, this technique uses the residual suture limbs of the knotless anchor for a second suture pass. This technique (1) creates a more cost- and time-efficient surgical procedure than using multiple single-loaded anchors or double-loaded anchors, (2) decreases the known risk of glenoid fracture from the stress riser at the implant tips of multi-anchor repairs by reducing the number of anchors required for stabilization, (3) decreases the surgical time compared with the use of double-loaded anchors through simpler suture management and less knot tying, (4) allows for the secure reapproximation of the labrum to the glenoid while offering a convenient option for capsulorrhaphy without the need to insert another anchor, and (5) yields more points of soft-tissue fixation with fewer anchors drilled into the glenoid.

  1. Self-tapping ability of carbon fibre reinforced polyetheretherketone suture anchors.

    PubMed

    Feerick, Emer M; Wilson, Joanne; Jarman-Smith, Marcus; Ó'Brádaigh, Conchur M; McGarry, J Patrick

    2014-10-01

    An experimental and computational investigation of the self-tapping ability of carbon fibre reinforced polyetheretherketone (CFR-PEEK) has been conducted. Six CFR-PEEK suture anchor designs were investigated using PEEK-OPTIMA® Reinforced, a medical grade of CFR-PEEK. Experimental tests were conducted to investigate the maximum axial force and torque required for self-taping insertion of each anchor design. Additional experimental tests were conducted for some anchor designs using pilot holes. Computational simulations were conducted to determine the maximum stress in each anchor design at various stages of insertion. Simulations also were performed to investigate the effect of wall thickness in the anchor head. The maximum axial force required to insert a self-tapping CFR-PEEK suture anchor did not exceed 150 N for any anchor design. The maximum torque required to insert a self-tapping CFR-PEEK suture anchor did not exceed 0.8 Nm. Computational simulations reveal significant stress concentrations in the region of the anchor tip, demonstrating that a re-design of the tip geometry should be performed to avoid fracture during self-tapping, as observed in the experimental component of this study. This study demonstrates the ability of PEEK-OPTIMA Reinforced suture anchors to self-tap polyurethane foam bone analogue. This provides motivation to further investigate the self-tapping ability of CFR-PEEK suture anchors in animal/cadaveric bone. An optimised design for CFR-PEEK suture anchors offers the advantages of radiolucency, and mechanical properties similar to bone with the ability to self-tap. This may have positive implications for reducing surgery times and the associated costs with the procedure.

  2. The floating anchored craniotomy.

    PubMed

    Gutman, Matthew J; How, Elena; Withers, Teresa

    2017-01-01

    The "floating anchored" craniotomy is a technique utilized at our tertiary neurosurgery institution in which a traditional decompressive craniectomy has been substituted for a floating craniotomy. The hypothesized advantages of this technique include adequate decompression, reduction in the intracranial pressure, obviating the need for a secondary cranioplasty, maintained bone protection, preventing the syndrome of the trephined, and a potential reduction in axonal stretching. The bone plate is re-attached via multiple loosely affixed vicryl sutures, enabling decompression, but then ensuring the bone returns to its anatomical position once cerebral edema has subsided. From the analysis of 57 consecutive patients analyzed at our institution, we have found that the floating anchored craniotomy is comparable to decompressive craniectomy for intracranial pressure reduction and has some significant theoretical advantages. Despite the potential advantages of techniques that avoid the need for a second cranioplasty, they have not been widely adopted and have been omitted from trials examining the utility of decompressive surgery. This retrospective analysis of prospectively collected data suggests that the floating anchored craniotomy may be applicable instead of decompressive craniectomy.

  3. Anchored paired comparisons

    NASA Astrophysics Data System (ADS)

    Dalal, E. N.; Handley, J. C.; Wu, W.; Wang, J.

    2008-01-01

    The method of paired comparisons is often used in image quality evaluations. Psychometric scale values for quality judgments are modeled using Thurstone's Law of Comparative Judgment in which distance in a psychometric scale space is a function of the probability of preference. The transformation from psychometric space to probability is a cumulative probability distribution. The major drawback of a complete paired comparison experiment is that every treatment is compared to every other, thus the number of comparisons grows quadratically. We ameliorate this difficulty by performing paired comparisons in two stages, by precisely estimating anchors in the psychometric scale space which are spaced apart to cover the range of scale values and comparing treatments against those anchors. In this model, we employ a generalized linear model where the regression equation has a constant offset vector determined by the anchors. The result of this formulation is a straightforward statistical model easily analyzed using any modern statistics package. This enables model fitting and diagnostics. This method was applied to overall preference evaluations of color pictorial hardcopy images. The results were found to be compatible with complete paired comparison experiments, but with significantly less effort.

  4. Kinetic Anisotropy and Dendritic Growth in Electrochemical Deposition

    NASA Astrophysics Data System (ADS)

    Barkey, D.; Oberholtzer, F.; Wu, Q.

    1995-10-01

    It is shown that kinetic anisotropy stabilizes dendritic growth in electrochemical deposition of copper, and that in its absence the growth tips are unstable to splitting. The degree of anisotropy in the interfacial dynamics, which may be controlled through the chemistry of the electrolyte solution, was determined by the measurement of open-circuit potentials of single-crystal electrodes under nonequilibrium conditions. The experiments provide direct evidence that microscopic interfacial anisotropy in depositional growth stabilizes the dendritic morphology.

  5. Nak regulates localization of clathrin sites in higher-order dendrites to promote local dendrite growth.

    PubMed

    Yang, Wei-Kang; Peng, Yu-Huei; Li, Hsun; Lin, Hsiu-Chen; Lin, Yu-Ching; Lai, Tzu-Ting; Suo, Hsien; Wang, Chien-Hsiang; Lin, Wei-Hsiang; Ou, Chan-Yen; Zhou, Xin; Pi, Haiwei; Chang, Henry C; Chien, Cheng-Ting

    2011-10-20

    During development, dendrites arborize in a field several hundred folds of their soma size, a process regulated by intrinsic transcription program and cell adhesion molecule (CAM)-mediated interaction. However, underlying cellular machineries that govern distal higher-order dendrite extension remain largely unknown. Here, we show that Nak, a clathrin adaptor-associated kinase, promotes higher-order dendrite growth through endocytosis. In nak mutants, both the number and length of higher-order dendrites are reduced, which are phenocopied by disruptions of clathrin-mediated endocytosis. Nak interacts genetically with components of the endocytic pathway, colocalizes with clathrin puncta, and is required for dendritic localization of clathrin puncta. More importantly, these Nak-containing clathrin structures preferentially localize to branching points and dendritic tips that are undergoing active growth. We present evidence that the Drosophila L1-CAM homolog Neuroglian is a relevant cargo of Nak-dependent internalization, suggesting that localized clathrin-mediated endocytosis of CAMs facilitates the extension of nearby higher-order dendrites. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Numerical Simulation of Dendritic Growth of Continuously Cast High Carbon Steel

    NASA Astrophysics Data System (ADS)

    Wang, Weiling; Luo, Sen; Zhu, Miaoyong

    2015-01-01

    Considering the influence of the latent heat released during the solidification of high carbon liquid steel, a cellular automaton (CA) model coupled with the heat transfer was developed to investigate the growth of equiaxed dendrites which is controlled by the solute diffusion during the continuous casting process. Additionally, the growth of columnar dendrites and primary dendrite arm spacings were predicted and measured. The results show that the CA model is able to describe the growth behavior of equiaxed dendrites, especially at 5 K to 7 K melt undercoolings, and the approach adjusting the cooling medium temperature is reliable to keep the undercooling condition stable for equiaxed dendrites although its hysteresis is reinforced as the pre-set undercooling increases. With the increase of the melt undercooling, the growth of equiaxed dendrites becomes faster, and the thickness of dendritic arms increases slightly, however, the thickness of the diffusion layer in front of dendritic tips keeps constant. The growth of thin and tiny columnar dendrites will be confined due to the competition and absorbed by neighboring strong columnar dendrites, giving rise to the coarsening of columnar dendrites, which is observed both from the experimental observation and the numerical simulation. With the decrease of the cooling intensity, columnar dendrites get sparser, primary dendrite arm spacings increase, and secondary dendritic arms become undeveloped.

  7. The Isothermal Dendritic Growth Experiment (IDGE)

    NASA Technical Reports Server (NTRS)

    Glicksman, Martin E.; Koss, M. B.; Lupulescu, A. O.; LaCombe, J. C.; Frei, J. E.; Malarik, D. C.

    1999-01-01

    The Isothermal Dendritic Growth Experiment (IDGE) constituted a series of three NASA-supported microgravity experiments, all of which flew aboard the space shuttle, Columbia. This experimental space flight series was designed and operated to grow and record dendrite solidification in the absence of gravity-induced convective heat transfer, and thereby produce a wealth of benchmark-quality data for testing solidification scaling laws. The data and analysis performed on the dendritic growth speed and tip size in Succinontrie (SCN) demonstrates that although the theory yields predictions that are reasonably in agreement with experiment, there are significant discrepancies. However, some of these discrepancies can be explained by accurately describing the diffusion of heat. The key finding involves recognition that the actual three-dimensional shape of dendrites includes time-dependent side-branching and a tip region that is not a paraboloid of revolution. Thus, the role of heat transfer in dendritic growth is validated, with the caveat that a more realistic model of the dendrite then a paraboloid is needed to account for heat flow in an experimentally observed dendrite. We are currently conducting additional analysis to further confirm and demonstrate these conclusions. The data and analyses for the growth selection physics remain much less definitive. From the first flight, the data indicated that the selection parameter, sigma*, is not exactly a constant, but exhibits a slight dependence on the supercooling. Additional data from the second flight are being examined to investigate the selection of a unique dendrite speed, tip size and shape. The IDGE flight series is now complete. We are currently completing analyses and moving towards final data archiving. It is gratifying to see that the IDGE published results and archived data sets are being used actively by other scientists and engineers. In addition, we are also pleased to report that the techniques and IDGE

  8. Tips for Daily Living

    MedlinePlus

    ... Tips and Gadgets for Daily Activities Dressing Tips Shopping Tips Modifying the Bathroom Driving After Stroke Medication ... and resources. Find a group in your area . Online Support If there is not a support group ...

  9. Dendritic growth in a supercooled alloy melt

    NASA Technical Reports Server (NTRS)

    Laxmanan, V.

    1987-01-01

    A simple model which describes the growth of an 'array' of dendrites into a supercooled, binary, alloy melt is presented. Solute diffusion is calculated by superposing the solutions given by Flemings and Zener, and also, by superposing the solutions given by Ivantsov and Flemings. A general expression for the transport solution is suggested from which all other dendrite growth models presented earlier may be obtained as special cases. It is shown that both 'free' and 'constrained' growth may be described by a single transport solution, which indicates that (1) both thermal and solutal effects will be important during 'free' growth in dilute alloys, (2) only solutal effects are predominant during 'free' growth in concentrated alloys and during 'constrained' growth. An examination of the relevant dimensionless parameters also suggests that all dendrite growth models, regardless of the assumptions used to determine the tip radius (marginal stability, minimum undercooling, maximum velocity, minimum entropy production) should predict the experimentally observed extrema in tip radius and growth velocity in dilute alloys, during 'free' dendritic growth. Experimental data in binary H2O-NaCl and succinonitrile-acetone solutions are shown to be in good agreement with the model.

  10. Bellow seal and anchor

    DOEpatents

    Mansure, Arthur J.

    2001-01-01

    An annular seal is made of a collapsible bellows. The bellows can function as an anchor or a seal and is easily set into position using relative component movement. The bellows folds can be slanted and their outer sealing edges can have different profiles to meet expected conditions. The bellows is expanded for insertion to reduce its outer dimension and sets by compaction as a result of relative movement. The bellows can be straight or tapered and is settable with a minimal axial force.

  11. Quantitative phase-field modeling of dendritic electrodeposition

    NASA Astrophysics Data System (ADS)

    Cogswell, Daniel A.

    2015-07-01

    A thin-interface phase-field model of electrochemical interfaces is developed based on Marcus kinetics for concentrated solutions, and used to simulate dendrite growth during electrodeposition of metals. The model is derived in the grand electrochemical potential to permit the interface to be widened to reach experimental length and time scales, and electroneutrality is formulated to eliminate the Debye length. Quantitative agreement is achieved with zinc Faradaic reaction kinetics, fractal growth dimension, tip velocity, and radius of curvature. Reducing the exchange current density is found to suppress the growth of dendrites, and screening electrolytes by their exchange currents is suggested as a strategy for controlling dendrite growth in batteries.

  12. Career anchors of dentist leaders.

    PubMed

    Tuononen, Tiina; Lammintakanen, Johanna; Suominen, Anna Liisa

    2016-08-01

    The work of a health care leader is demanding; in order to cope, leaders need motivation and support. The occurrence of intrinsic factors called career anchors (combination of one's competence, motives and values) could be a contributing factor in dentist leaders' career decisions. The aim of our study was to identify dentist leaders' career anchors and their association to dentist leaders' retention or turnover of the leadership position. Materials were gathered in 2014 via an electronic questionnaire from 156 current (Leaders) or former (Leavers) Finnish dentist leaders. Career anchor evaluation was conducted by the questionnaire and scoring-table taken from Edgar Schein's Career Anchors Self-Assessment. Both the most and the least important career anchors were detected by the highest and lowest scores and their occurrence reported as percentages. Associations between career anchor scores and tendency to stay were analyzed with logistic regression. 'Technical/Functional Competence' and 'Lifestyle' were most frequently reported as the most important and 'Entrepreneurial Creativity' and 'General Managerial Competence' as the least important career anchors. However, a higher level of 'General Managerial Competence' anchor was most significantly associated with staying in a leadership position. Instead, 'Pure Challenge' and 'Lifestyle' decreased the odds to stay. The knowledge of the important and essential career anchors of dentist leaders' and individuals' could perform crucial part in career choices and also in planning education, work opportunities and human resource policies promoting retention of dentist leaders and probably also other health care leaders.

  13. Dendritic spikes veto inhibition.

    PubMed

    Stuart, Greg J

    2012-09-06

    How inhibition regulates dendritic excitability is critical to an understanding of the way neurons integrate the many thousands of synaptic inputs they receive. In this issue of Neuron, Müller et al. (2012) show that inhibition blocks the generation of weak dendritic spikes, leaving strong dendritic spikes intact. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Tips for Transition

    ERIC Educational Resources Information Center

    Kellems, Ryan, Comp.; Morningstar, Mary E., Comp.

    2009-01-01

    The Tips for Transition contains 134 Transition Tips submitted from all over the country by practitioners. The purpose of the Tips was to identify grassroots transition practices being used by practitioners. Tips are categorized into the following domains: (1) Transition Planning; (2) Student Involvement; (3) Family Involvement; (4) Curriculum and…

  15. Probe tip heating assembly

    SciTech Connect

    Schmitz, Roger William; Oh, Yunje

    2016-10-25

    A heating assembly configured for use in mechanical testing at a scale of microns or less. The heating assembly includes a probe tip assembly configured for coupling with a transducer of the mechanical testing system. The probe tip assembly includes a probe tip heater system having a heating element, a probe tip coupled with the probe tip heater system, and a heater socket assembly. The heater socket assembly, in one example, includes a yoke and a heater interface that form a socket within the heater socket assembly. The probe tip heater system, coupled with the probe tip, is slidably received and clamped within the socket.

  16. CHEMICAL SYNTHESIS OF GLYCOSYLPHOSPHATIDYLINOSITOL ANCHORS

    PubMed Central

    Swarts, Benjamin M.; Guo, Zhongwu

    2013-01-01

    Many eukaryotic cell-surface proteins and glycoproteins are anchored to the plasma membrane by glycosylphosphatidylinositols (GPIs), a family of glycolipids that are post-translationally attached to proteins at their C-termini. GPIs and GPI-anchored proteins play important roles in many biological and pathological events, such as cell recognition and adhesion, signal transduction, host defense, and acting as receptors for viruses and toxins. Chemical synthesis of structurally defined GPI anchors and GPI derivatives is a necessary step toward understanding the properties and functions of these molecules in biological systems and exploring their potential therapeutic applications. In the first part of this comprehensive article on the chemical synthesis of GPIs, classic syntheses of naturally occurring GPI anchors from protozoan parasites, yeast, and mammals are covered. The second part of the article focuses on recent diversity-oriented strategies for the synthesis of GPI anchors containing unsaturated lipids, “click chemistry” tags, and highly branched and modified structures. PMID:22794184

  17. Granular Simulation of NEO Anchoring

    NASA Technical Reports Server (NTRS)

    Mazhar, Hammad

    2011-01-01

    NASA is interested in designing a spacecraft capable of visiting a Near Earth Object (NEO), performing experiments, and then returning safely. Certain periods of this mission will require the spacecraft to remain stationary relative to the NEO. Such situations require an anchoring mechanism that is compact, easy to deploy and upon mission completion, easily removed. The design philosophy used in the project relies on the simulation capability of a multibody dynamics physics engine. On Earth it is difficult to create low gravity conditions and testing in low gravity environments, whether artificial or in space is costly and therefore not feasible. Through simulation, gravity can be controlled with great accuracy, making it ideally suited to analyze the problem at hand. Using Chrono::Engine [1], a simulation package capable of utilizing massively parallel GPU hardware, several validation experiments will be performed. Once there is sufficient confidence, modeling of the NEO regolith interaction will begin after which the anchor tests will be performed and analyzed. The outcome of this task is a study with an analysis of several different anchor designs, along with a recommendation on which anchor is better suited to the task of anchoring. With the anchors tested against a range of parameters relating to soil, environment and anchor penetration angles/velocities on a NEO.

  18. Granular Simulation of NEO Anchoring

    NASA Technical Reports Server (NTRS)

    Mazhar, Hammad

    2011-01-01

    NASA is interested in designing a spacecraft capable of visiting a Near Earth Object (NEO), performing experiments, and then returning safely. Certain periods of this mission will require the spacecraft to remain stationary relative to the NEO. Such situations require an anchoring mechanism that is compact, easy to deploy and upon mission completion, easily removed. The design philosophy used in the project relies on the simulation capability of a multibody dynamics physics engine. On Earth it is difficult to create low gravity conditions and testing in low gravity environments, whether artificial or in space is costly and therefore not feasible. Through simulation, gravity can be controlled with great accuracy, making it ideally suited to analyze the problem at hand. Using Chrono::Engine [1], a simulation package capable of utilizing massively parallel GPU hardware, several validation experiments will be performed. Once there is sufficient confidence, modeling of the NEO regolith interaction will begin after which the anchor tests will be performed and analyzed. The outcome of this task is a study with an analysis of several different anchor designs, along with a recommendation on which anchor is better suited to the task of anchoring. With the anchors tested against a range of parameters relating to soil, environment and anchor penetration angles/velocities on a NEO.

  19. The Evolution of Topologically Complex Structures: Coarsening of Dendritic Mixtures - Final Report.

    SciTech Connect

    K. Thornton; Peter W. Voorhees

    2009-10-08

    Dendrites frequently form during solidification into an undercooled melt. These dendrites possess secondary and sometimes even ternary arms. While the tip radius and tip velocity of the dendrite are set by the growth conditions, the side branches behind the tip undergo a coarsening process under nearly isothermal conditions. This coarsening process sets an arm thickness and distances between dendrite arms in the solidified structure that are almost independent of the length-scale given by the dendrite tip. Since there is a close relationship between the size scale of the dendrites and the mechanical properties of the material, the coarsening process in dendritic solid-liquid systems has received much attention. Despite the clear importance of the coarsening process, measurements of the morphology of the two-phase mixture during coarsening that capture the full three-dimensional nature of the structure are in their infancy. In addition, since calculations of the evolution of such topologically complex systems are challenging, existing models of this coarsening process involve significant simplifications of the microstructure. To address these deficiencies in our understanding of the coarsening process, we study the coarsening process in topologically complex systems using three-dimensional reconstructions of the microstructure in concert with phase-field calculations of the local interfacial velocities.

  20. Transition from a planar interface to cellular and dendritic structures during rapid solidification processing

    NASA Technical Reports Server (NTRS)

    Laxmanan, V.

    1986-01-01

    The development of theoretical models which characterize the planar-cellular and cell-dendrite transitions is described. The transitions are analyzed in terms of the Chalmers number, the solute Peclet number, and the tip stability parameter, which correlate microstructural features and processing conditions. The planar-cellular transition is examined using the constitutional supercooling theory of Chalmers et al., (1953) and it is observed that the Chalmers number is between 0 and 1 during dendritic and cellular growth. Analysis of cell-dendrite transition data reveal that the transition occurs when the solute Peclet number goes through a minimum, the primary arm spacings go through a maximum, and the Chalmers number is equal to 1/2. The relation between the tip stability parameter and the solute Peclet number is investigated and it is noted that the tip stability parameter is useful for studying dendritic growth in alloys.

  1. Transition from a planar interface to cellular and dendritic structures during rapid solidification processing

    NASA Technical Reports Server (NTRS)

    Laxmanan, V.

    1986-01-01

    The development of theoretical models which characterize the planar-cellular and cell-dendrite transitions is described. The transitions are analyzed in terms of the Chalmers number, the solute Peclet number, and the tip stability parameter, which correlate microstructural features and processing conditions. The planar-cellular transition is examined using the constitutional supercooling theory of Chalmers et al., (1953) and it is observed that the Chalmers number is between 0 and 1 during dendritic and cellular growth. Analysis of cell-dendrite transition data reveal that the transition occurs when the solute Peclet number goes through a minimum, the primary arm spacings go through a maximum, and the Chalmers number is equal to 1/2. The relation between the tip stability parameter and the solute Peclet number is investigated and it is noted that the tip stability parameter is useful for studying dendritic growth in alloys.

  2. Seals, Concrete Anchors, and Connections

    DTIC Science & Technology

    1989-02-01

    Plastic Anchors, Topline Nylon Nailins, and Topline Iamnmer Drive Anchors. Similar anchors are made by Rawl (Rawl Nylon Nailin, Rawl Zamac Nailin...Toggle Bolt GSA Specification FF-B-588C, • • • lype 1, Class A. Style 1. . Zamac Nailin GSA Specification FF-S-325. I K ,Group V Type;’ U. Clss3. Tested...instal[ No hole spotting, 3- Tpor’ block, brick fastener needed `1eAt X" 6" removable. 2 head styles. 30 sizes. Zamac Concrete, block. No other Zinc alloy

  3. In situ synchrotron X-ray studies of the coupled effects of thermal and solutal supercoolings on the instability of dendrite growth

    SciTech Connect

    Li, Faguo; Zhang, Jiao; Dong, Qing; Dai, Yongbing; Fu, Yanan; Xie, Honglan; Mi, J.; Yin, Fucheng; Sun, Baode

    2015-11-15

    Special growth pattern representing unique growth conditions is a vital clue to investigate the morphology evolution mechanism in metallic alloy solidification. The dendrite pattern and growth orientation of dendritic doublons in the hypoeutectic Al-Cu alloy have been studied by synchrotron radiation imaging technology and electron back scatter diffraction. The results show that this kind of doublon is two-dimensional and the secondary arms grow perpendicularly to the primary stem. This doublon morphology can appear as an equiaxed grain, columnar dendrite, or coexist with a regular dendrite. The growth directions of the dendritic doublon tips and the secondary arms are < 110 > and < 001 >, respectively. Rising cooling rate or Cu concentration in the alloys facilitates the formation of the doublonic structure. According to the kinetic morphology diagram of Al-Cu alloys (pattern-dimensionless supercooling-anisotropy) obtained from the experimental data, the dendritic doublon forming region was above the boundary of fractal dendrite and compact dendrite. - Highlights: • The morphology of dendritic doublon was found growing in equiaxed or columnar dendritic manner, or coexisting with regular stems in an equiaxed dendrite. • The growth orientations of dendritic doublon tip and secondary arms are < 110 > and < 001 >, respectively. • Doublon dendrite is considered a kind of transitional growth pattern; the variation of either Cu composition or cooling rate affects the formation probability of the doublon-type dendrite.

  4. Interfacial wave theory of dendrite growth - Global mode solution and quantum condition

    NASA Technical Reports Server (NTRS)

    Xu, Jian-Jun

    1990-01-01

    The signal feedback process at the edge of the dendrite tip is investigated, and the global instability mechanism of the system is derived. A mechanism is developed to describe a discrete set of unstable global modes for the system. Called WEASR, the method considers the wave emission at the turning point and signal reflections between the turning point and the front edge of the tip. It is shown that the method can obtain the asymptotic solutions for the unstable global modes and the quantum condition for the corresponding eigenvalues. A turning point called the pattern formation condition is shown to be crucial in the formation of dendritic structure and the choice of the final tip velocity. The wave emission process is outlined, and the importance of a signal feedback process at the edge of the dendrite tip is demonstrated. Parameters such as stability and surface tension can be analyzed in terms of their effects on WEASR modes.

  5. Interfacial wave theory of dendrite growth - Global mode solution and quantum condition

    NASA Technical Reports Server (NTRS)

    Xu, Jian-Jun

    1990-01-01

    The signal feedback process at the edge of the dendrite tip is investigated, and the global instability mechanism of the system is derived. A mechanism is developed to describe a discrete set of unstable global modes for the system. Called WEASR, the method considers the wave emission at the turning point and signal reflections between the turning point and the front edge of the tip. It is shown that the method can obtain the asymptotic solutions for the unstable global modes and the quantum condition for the corresponding eigenvalues. A turning point called the pattern formation condition is shown to be crucial in the formation of dendritic structure and the choice of the final tip velocity. The wave emission process is outlined, and the importance of a signal feedback process at the edge of the dendrite tip is demonstrated. Parameters such as stability and surface tension can be analyzed in terms of their effects on WEASR modes.

  6. Dendritic polyurea polymers.

    PubMed

    Tuerp, David; Bruchmann, Bernd

    2015-01-01

    Dendritic polymers, subsuming dendrimers as well as hyperbranched or highly branched polymers are well established in the field of polymer chemistry. This review article focuses on urea based dendritic polymers and summarizes their synthetic routes through both isocyanate and isocyanate-free processes. Furthermore, this article highlights applications where dendritic polyureas show their specific chemical and physical potential. For these purposes scientific publications as well as patent literature are investigated to generate a comprehensive overview on this topic.

  7. Slender tip laser scalpel

    DOEpatents

    Veligdan, James T.

    2004-01-06

    A laser scalpel includes a ribbon optical waveguide extending therethrough and terminating at a slender optical cutting tip. A laser beam is emitted along the height of the cutting tip for cutting tissue therealong.

  8. The three-dimensional morphology of growing dendrites

    DOE PAGES

    Gibbs, J. W.; Mohan, K. A.; Gulsoy, E. B.; ...

    2015-07-03

    The processes controlling the morphology of dendrites have been of great interest to a wide range of communities, since they are examples of an out-of-equilibrium pattern forming system, there is a clear connection with battery failure processes, and their morphology sets the properties of many metallic alloys. We determine the three-dimensional morphology of free growing metallic dendrites using a novel X-ray tomographic technique that improves the temporal resolution by more than an order of magnitude compared to conventional techniques. These measurements show that the growth morphology of metallic dendrites is surprisingly different from that seen in model systems, the morphologymore » is not self-similar with distance back from the tip, and that this morphology can have an unexpectedly strong influence on solute segregation in castings. As a result, these experiments also provide benchmark data that can be used to validate simulations of free dendritic growth.« less

  9. The three-dimensional morphology of growing dendrites

    SciTech Connect

    Gibbs, J. W.; Mohan, K. A.; Gulsoy, E. B.; Shahani, A. J.; Xiao, X.; Bouman, C. A.; De Graef, M.; Voorhees, P. W.

    2015-07-03

    The processes controlling the morphology of dendrites have been of great interest to a wide range of communities, since they are examples of an out-of-equilibrium pattern forming system, there is a clear connection with battery failure processes, and their morphology sets the properties of many metallic alloys. We determine the three-dimensional morphology of free growing metallic dendrites using a novel X-ray tomographic technique that improves the temporal resolution by more than an order of magnitude compared to conventional techniques. These measurements show that the growth morphology of metallic dendrites is surprisingly different from that seen in model systems, the morphology is not self-similar with distance back from the tip, and that this morphology can have an unexpectedly strong influence on solute segregation in castings. As a result, these experiments also provide benchmark data that can be used to validate simulations of free dendritic growth.

  10. The Three-Dimensional Morphology of Growing Dendrites

    PubMed Central

    Gibbs, J. W.; Mohan, K. A.; Gulsoy, E. B.; Shahani, A. J.; Xiao, X.; Bouman, C. A.; De Graef, M.; Voorhees, P. W.

    2015-01-01

    The processes controlling the morphology of dendrites have been of great interest to a wide range of communities, since they are examples of an out-of-equilibrium pattern forming system, there is a clear connection with battery failure processes, and their morphology sets the properties of many metallic alloys. We determine the three-dimensional morphology of free growing metallic dendrites using a novel X-ray tomographic technique that improves the temporal resolution by more than an order of magnitude compared to conventional techniques. These measurements show that the growth morphology of metallic dendrites is surprisingly different from that seen in model systems, the morphology is not self-similar with distance back from the tip, and that this morphology can have an unexpectedly strong influence on solute segregation in castings. These experiments also provide benchmark data that can be used to validate simulations of free dendritic growth. PMID:26139473

  11. Model anchor tests in cohesionless soil

    SciTech Connect

    Walker, G.R.; Taylor, R.J.

    1983-05-01

    Tandem (piggyback), parallel, and single model anchor tests have been performed in cohesionless soil. Tandem anchor arrangements have been found that result in a tandem system capacity that exceeds twice the capacity of a single anchor. These methods are operationally feasible and offer the potential for anchor weight savings.

  12. 100 Tips for Parents.

    ERIC Educational Resources Information Center

    Department of Education, Washington, DC.

    Noting that involved parents can improve their children's chances of succeeding in school, this packet of cards offers 100 tips created to help parents become more involved in their child's education. Following a card of general tips on becoming involved, tips are offered in the following topic areas: helping a child stay alcohol, tobacco, and…

  13. Child Transportation Safety Tips.

    ERIC Educational Resources Information Center

    National Highway Traffic Safety Administration (DOT), Washington, DC.

    This document presents nine tips regarding safe infant and child transportation, each tip explained in one to two pages. The tips are as follows: (1) quick safety seat checkup; (2) where should your child ride? (3) how to protect your new baby in the car; (4) what safety seat to use for a big baby or toddler? (5) how should preschool and school…

  14. Novel Technique for Proximal Bone Anchoring of Penile Prosthesis After Radial Forearm Free Flap Neophallus.

    PubMed

    Cohen, Andrew J; Bhanvadia, Raj R; Pariser, Joseph J; Hatcher, David M; Gottlieb, Lawrence J; Bales, Gregory T

    2017-02-02

    To describe outcomes of bone anchoring of penile implant in a neophallus with an accompanying video focusing on operative technique and salient tips for surgeons performing these procedures. Penile prosthesis insertion allows individuals with a neophallus to achieve erectile function. Lack of corporal bodies to accommodate cylinders makes anchoring of any prosthesis challenging. Anchoring the device to the pubic bone is one strategy to achieve proximal stabilization. A single-institution, retrospective chart review of 10 neophallus patients undergoing penile prosthesis placement from 2006 to 2015 was done. The pubic symphysis is exposed and corticotomy created for placement of the rear tip extender of the implant using a Stryker TPS bone drill. Anchoring sutures through the corticotomy defect, rear tip, and proximal cylinder seat the implant. The remainder of the implantation procedure mirrors that used in native tissue. The overall perioperative complication rate was 20%, with a mean follow-up of 49 months. Seventy percent of the patients required reoperation, with a mean of 1.4 prosthesis revision surgeries per patient. Primary causes of revision included infection, poor fixation of the rear tip, and prosthesis failure. Despite high revision rates, 80% of the patients have fully functioning prosthesis as of last follow-up. Limitations include retrospective study design and the small patient cohort. Penile prosthesis placement in the neophallus is feasible and effective. A bone-anchored rear tip is an option to provide proximal stabilization. Continued efforts to minimize the need for revisions are ongoing and necessary. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Analyzing paleomagnetic data: To anchor or not to anchor?

    NASA Astrophysics Data System (ADS)

    Heslop, David; Roberts, Andrew P.

    2016-11-01

    Paleomagnetic directions provide the basis for use of paleomagnetism in chronological and tectonic reconstructions and for constraining past geomagnetic field behavior over a variety of timescales. Crucial to paleomagnetic analysis is the separation and quantification of a characteristic remanent magnetization (ChRM), which relates to a process of interest, from other remanence components. Principal component analysis (PCA) of stepwise demagnetization data is employed routinely in these situations to estimate magnetic remanence directions and their uncertainties. A given ChRM is often assumed to trend toward the origin of a vector demagnetization diagram and prevailing data analysis frameworks allow remanence directions to be estimated based on PCA fits that are forced to pass through the origin of such diagrams, a process referred to as "anchoring." While this approach is adopted commonly, little attention has been paid to the effects of anchoring and the influence it has on both estimated remanence directions and their associated uncertainties. In almost all cases, anchoring produces an artificially low uncertainty estimation compared to an unanchored fit. Bayesian model selection demonstrates that the effects of anchoring cannot typically be justified from a statistical standpoint. We present an alternative to anchoring that constrains the best fit remanence direction to pass through the origin of a vector demagnetization diagram without unreasonably distorting the representation of the demagnetization data.

  16. Activity-Dependent Regulation of Dendritic Complexity by Semaphorin 3A through Farp1

    PubMed Central

    Cheadle, Lucas

    2014-01-01

    Dendritic arbors are complex neuronal structures that receive and process synaptic inputs. One mechanism regulating dendrite differentiation is Semaphorin/Plexin signaling, specifically through binding of soluble Sema3A to Neuropilin/PlexinA coreceptors. Here we show that the protein Farp1 [FERM, RhoGEF (ARHGEF), and pleckstrin domain protein 1], a Rac1 activator previously identified as a synaptogenic signaling protein, contributes to establishing dendrite tip number and total dendritic branch length in maturing rat neurons and is sufficient to promote dendrite complexity. Aiming to define its upstream partners, our results support that Farp1 interacts with the Neuropilin-1/PlexinA1 complex and colocalizes with PlexinA1 along dendritic shafts. Functionally, Farp1 is required by Sema3A to promote dendritic arborization of hippocampal neurons, and Sema3A regulates dendritic F-actin distribution via Farp1. Unexpectedly, Sema3A also requires neuronal activity to promote dendritic complexity, presumably because silencing neurons leads to a proteasome-dependent reduction of PlexinA1 in dendrites. These results provide new insights into how activity and soluble cues cooperate to refine dendritic morphology through intracellular signaling pathways. PMID:24899721

  17. Influence of lower frequency electromagnetic field on dendritic crystal growth in special alloys

    NASA Astrophysics Data System (ADS)

    Xu, Yu; Wang, Tao; Wang, Fei; Wang, Engang

    2017-06-01

    Based on a new developed chemical etching method to special alloys (e.g. Incoloy800H superalloy, GCr15 bearing steel and 1Cr13 stainless steel), the morphology of dendritic crystal growth and its transition to equiaxed crystal in the solidification structure with lower frequency electromagnetic fields were observed and investigated to understand the action mechanism of electromagnetic fields on the solidification of the special alloys. By applying a rotating electromagnetic field (REMF) in the casting of special alloys, the growth condition of dendritic crystals, such as the temperature gradient and concentration of elements in the front of dendritic crystals, have been changed by the forced convection of melt and bring the columnar dendrites to equiaxed dendrites. These phenomena are proved in the morphology observation of the Incoloy800H superalloy, GCr15 steel and 1Cr13 steel by the new developed chemical etching method, and the tips of dendritic crystals are changed from sharp to round. Meanwhile, with the application of REMF, the growing dendrites are broken in the front of dendritic crystals by the forced melt flow. Some of the dendrite fragments are partially remelted to become effective nuclei, and some of them are survived during the solidification process. Finally, a criterion for the dendrite fragmentation under REMF is derived based on the dendrite fragmentation theory of Campanella et al.

  18. Selected mode of dendritic growth with n-fold symmetry in the presence of a forced flow

    NASA Astrophysics Data System (ADS)

    Alexandrov, D. V.; Galenko, P. K.

    2017-07-01

    The effect of n-fold crystal symmetry is investigated for a two-dimensional stable dendritic growth in the presence of a forced convective flow. We consider dendritic growth in a one-component undercooled liquid. The theory is developed for the parabolic solid-liquid surface of dendrite growing at arbitrary growth Péclet numbers keeping in mind small anisotropies of surface energy and growth kinetics. The selection criterion determining the stable growth velocity of the dendritic tip and its stable tip diameter is found on the basis of solvability analysis. The obtained criterion includes previously developed theories of thermally and kinetically controlled dendritic growth with convection for the case of four-fold crystal symmetry. The obtained nonlinear system of equations (representing the selection criterion and undercooling balance) for the determination of dendrite tip velocity and dendrite tip diameter is analytically solved in a parametric form. These exact solutions clearly demonstrate a transition between thermally and kinetically controlled growth regimes. In addition, we show that the dendrites with larger crystal symmetry grow faster than those with smaller symmetry.

  19. Arctic climate tipping points.

    PubMed

    Lenton, Timothy M

    2012-02-01

    There is widespread concern that anthropogenic global warming will trigger Arctic climate tipping points. The Arctic has a long history of natural, abrupt climate changes, which together with current observations and model projections, can help us to identify which parts of the Arctic climate system might pass future tipping points. Here the climate tipping points are defined, noting that not all of them involve bifurcations leading to irreversible change. Past abrupt climate changes in the Arctic are briefly reviewed. Then, the current behaviour of a range of Arctic systems is summarised. Looking ahead, a range of potential tipping phenomena are described. This leads to a revised and expanded list of potential Arctic climate tipping elements, whose likelihood is assessed, in terms of how much warming will be required to tip them. Finally, the available responses are considered, especially the prospects for avoiding Arctic climate tipping points.

  20. Using the anchoring device of a comet lander to determine surface mechanical properties

    NASA Astrophysics Data System (ADS)

    Kömle, Norbert I.; Ball, Andrew J.; Kargl, Günter; Stöcker, Jakob; Thiel, Markus; Jolly, Harjinder S.; Dziruni, Masarapauya; Zarnecki, John C.

    1997-12-01

    Owing to the low surface gravity of the Rosetta target comet 46P/Wirtanen, a means of anchoring the Rosetta Lander to the cometary surface will be necessary. This task can be accomplished by firing an anchor into the cometary soil immediately after touchdown to prevent a rebound of the spacecraft from the surface or subsequent ejection by other forces, and to allow for mechanical activities (drilling, etc.) at the landing site. The rationale for anchoring is examined, based on estimates of the main forces likely to act on the spacecraft after landing. We report on the development of an anchoring device using a pyrotechnic gas generator as a power source and an instrumented anchor. In addition to the anchoring function, which is the primary purpose of this system, the integration of acceleration and temperature sensors into the tip offers the possibility to determine some important material properties of the cometary surface layer. The accelerometer is designed to measure the deceleration history of the projectile and is thus expected to give information on how the material properties (in particular strength) change within the penetrated layer(s), while the temperature sensor will measure temperature variations at the depth at which the anchor finally comes to rest. As the mechanical properties of the material are not known, it is difficult to predict the final depth of the anchor with any great certainty, but it may well be greater than that reached by any other of the lander's instruments. The instrumented anchor will be part of the MUPUS experiment, selected to form part of the Rosetta Lander payload. We report on results of laboratory simulations of anchor penetration performed at the Institut für Weltraumforschung, Graz, and compare these with models of projectile penetration. The value of the results expected from the penetrometry experiment in the context of an improved understanding of cometary processes is discussed.

  1. The correlation between dendritic microstructure and mechanical properties of directionally solidified hypoeutectic Al-Ni alloys

    NASA Astrophysics Data System (ADS)

    Canté, Manuel V.; Spinelli, José E.; Cheung, Noé; Garcia, Amauri

    2010-02-01

    Al-Ni hypoeutectic alloys were directionally solidified under upward transient heat flow conditions. The aim of the present study is to set up correlations between the as-cast microstructure and the resulting mechanical properties of these alloys. The dependence of primary and secondary dendrite arm spacing on the alloy solute content and on solidification thermal parameters is also analyzed. The results include transient metal/mold heat transfer coefficient, tip growth rate, cooling rate, dendrite arm spacing, ultimate tensile strength, yield tensile strength and elongation. Expressions relating dendrite spacing to solidification thermal parameters and mechanical properties to the scale of the dendritic microstructure have been determined. It was found that the ultimate tensile strength and the yield tensile strength increase with increasing alloy solute content and with decreasing primary and secondary dendrite arm spacing. In contrast, the elongation was found to be independent of both alloy composition and dendritic arrangement.

  2. Cellular and dendritic growth in a binary melt - A marginal stability approach

    NASA Technical Reports Server (NTRS)

    Laxmanan, V.

    1986-01-01

    A simple model for the constrained growth of an array of cells or dendrites in a binary alloy in the presence of an imposed positive temperature gradient in the liquid is proposed, with the dendritic or cell tip radius calculated using the marginal stability criterion of Langer and Muller-Krumbhaar (1977). This approach, an approach adopting the ad hoc assumption of minimum undercooling at the cell or dendrite tip, and an approach based on the stability criterion of Trivedi (1980) all predict tip radii to within 30 percent of each other, and yield a simple relationship between the tip radius and the growth conditions. Good agreement is found between predictions and data obtained in a succinonitrile-acetone system, and under the present experimental conditions, the dendritic tip stability parameter value is found to be twice that obtained previously, possibly due to a transition in morphology from a cellular structure with just a few side branches, to a more fully developed dendritic structure.

  3. Disdrometer and Tipping Bucket Rain Gauge Handbook

    SciTech Connect

    Bartholomew. MJ

    2009-12-01

    The Distromet disdrometer model RD-80 and NovaLynx tipping bucket rain gauge model 260-2500E-12 are two devices deployed a few meters apart to measure the character and amount of liquid precipitation. The main purpose of the disdrometer is to measure drop size distribution, which it does over 20 size classes from 0.3 mm to 5.4 mm. The data from both instruments can be used to determine rain rate. The disdrometer results can also be used to infer several properties including drop number density, radar reflectivity, liquid water content, and energy flux. Two coefficients, N0 and Λ, from an exponential fit between drop diameter and drop number density, are routinely calculated. Data are collected once a minute. The instruments make completely different kinds of measurements. Rain that falls on the disdrometer sensor moves a plunger on a vertical axis. The disdrometer transforms the plunger motion into electrical impulses whose strength is proportional to drop diameter. The rain gauge is the conventional tipping bucket type. Each tip collects an amount equivalent to 0.01 in. of water, and each tip is counted by a data acquisition system anchored by a Campbell CR1000 data logger.

  4. Causes of TIPS dysfunction.

    PubMed

    Cura, Marco; Cura, Alejandro; Suri, Rajeev; El-Merhi, Fadi; Lopera, Jorge; Kroma, Ghazwan

    2008-12-01

    Transjugular intrahepatic portosystemic shunt (TIPS) creation is an effective method to control portal hypertension. TIPS creations with bare stents have shown limited and unpredictable patency. In nearly all cases of rebleeding or recurrent ascites after TIPS creation, there is shunt stenosis or occlusion. The purpose of this article is to review the biologic and technical factors that predispose to TIPS failure and how the use of an expandable polytetrafluoroethylene (PTFE)-covered-stent has significantly improved TIPS patency. Biologic and technical factors may predispose to shunt failure. The combination of improved technique and expandable PTFE has significantly improved TIPS patency. The need for follow-up venography and secondary interventions has been reduced significantly as a result of improved shunt patency.

  5. Helicopter blade tips

    NASA Technical Reports Server (NTRS)

    Lyothier, R.

    1983-01-01

    Methods of improving helicopter performance and vibration level by proper shaping of helicopter blade tips are considered. The principle involved consists of reducing the extent of the supersonic zone above the advancing tip and of the turbulent interaction. For stationary and advancing flight, the influence of the rotor and the problems posed by blade tips are reviewed. The theoretical methods of dealing with the two types of flight are briefly stated, and the experimental apparatus is described, including model triple and quadruple rotors. Different blade tip shapes are shown and briefly discussed. The theoretical results include an advancing speed of 309 km/H and a blade tip rotational speed of 215 m/s. The experimental values are advancing speed of 302 km/h and blade tip Mach number 0.86 for both types of rotors.

  6. Dendrite Model Explained

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Angie Jackman, a NASA project manager in microgravity research, explains a model of a dendrite to a visitor to the NASA exhibit at AirVenture 2000 sponsored by the Experimental Aircraft Association in Oshkosh, WI. The model depicts microscopic dendrites that grow as molten metals solidify. NASA sponsored three experiments aboard the Space Shuttle that used the microgravity environment to study the formation of large (1 to 4 mm) dendrites without Earth's gravity disrupting their growth. Three advanced follow-on experiments, managed by Jackman, are being developed for the International Space Station (ISS).

  7. How anchoring proteins shape pain.

    PubMed

    Fischer, Michael J M; McNaughton, Peter A

    2014-09-01

    Cellular responsiveness to external stimuli can be altered by extracellular mediators which activate membrane receptors, in turn signalling to the intracellular space via calcium, cyclic nucleotides, membrane lipids or enzyme activity. These signalling events trigger a cascade leading to an effector which can be a channel, an enzyme or a transcription factor. The effectiveness of these intracellular events is enhanced when they are maintained in close proximity by anchoring proteins, which assemble complexes of signalling molecules such as kinases together with their targets, and in this way enhance both the speed and the precision of intracellular signalling. The A kinase anchoring protein (AKAP) family are adaptor proteins originally named for their ability to associate Protein Kinase A and its targets, but several other enzymes bound by AKAPs have now been found and a wide variety of target structures has been described. This review provides an overview of anchoring proteins involved in pain signalling. The key anchoring proteins and their ion channel targets in primary sensory neurons responding to painful stimuli (nociceptors) are discussed.

  8. ATHLETE : Double Auger Anchoring Mechanism

    NASA Technical Reports Server (NTRS)

    Shin, Joseph

    2011-01-01

    The All-Terrain Hex-Legged Extra-Terrestrial Explorer (ATHLETE) is a six-limbed robot designed to support surface explorations on Near Earth Objects, the Moon and Mars. ATHLETE can carry large payloads on its top deck and can carry a fully equipped pressurized habitat in low gravity. The robot has wheels on each of its six articulated limbs, allowing it to actively conform to terrain while driving and to walk when driving is impractical. With the use of a tool adapter, ATHLETE limbs can be equipped with end effectors to support various mission objectives. For work on Near Earth Objects and other microgravity environments, an anchoring mechanism is needed to keep the ATHLETE from floating off the surface. My goal for this spring session at JPL was to design and build a counter rotating, double auger, anchoring mechanism. The mechanism mates to the tool adapter and is driven off the wheel motor. The double auger anchoring mechanism will be tested in a regolith simulant that will determine the uplift capacity of the anchoring mechanism.

  9. ATHLETE : Double Auger Anchoring Mechanism

    NASA Technical Reports Server (NTRS)

    Shin, Joseph

    2011-01-01

    The All-Terrain Hex-Legged Extra-Terrestrial Explorer (ATHLETE) is a six-limbed robot designed to support surface explorations on Near Earth Objects, the Moon and Mars. ATHLETE can carry large payloads on its top deck and can carry a fully equipped pressurized habitat in low gravity. The robot has wheels on each of its six articulated limbs, allowing it to actively conform to terrain while driving and to walk when driving is impractical. With the use of a tool adapter, ATHLETE limbs can be equipped with end effectors to support various mission objectives. For work on Near Earth Objects and other microgravity environments, an anchoring mechanism is needed to keep the ATHLETE from floating off the surface. My goal for this spring session at JPL was to design and build a counter rotating, double auger, anchoring mechanism. The mechanism mates to the tool adapter and is driven off the wheel motor. The double auger anchoring mechanism will be tested in a regolith simulant that will determine the uplift capacity of the anchoring mechanism.

  10. High Velocity Implanting of Anchors

    DTIC Science & Technology

    1984-07-01

    easily by a direct rocket. The sponsors had suggested a water jet approach using cold high pressure gas to supply the energy, instead of propellant gas...development promises to be expensive and lengthy. Fortunately, the water jet does not share this problem. Its development should be timely, and costs should be reasonable. Keyword: Anchors (Marine).

  11. A critical examination of the dendrite growth models Comparison of theory with experimental data

    NASA Technical Reports Server (NTRS)

    Tewari, S. N.; Laxmanan, V.

    1987-01-01

    Three dendrite growth models for directionally solidified succinonitrile-acetone, succinonitrile-salol, aluminum-copper, and lead-paladium alloys are evaluated. The characteristics of the Burden and Hunt (1974) model, the Laxmanan (1985) model, and the Trivedi (1980) model are described. The dendrite tip temperature, tip radius, liquid composition, and primary arm spacing for the alloys are analyzed in terms of growth speed, alloy composition, and temperature gradient. It is observed that the Burden and Hunt model accurately predicts the proper behavior of the parameters, but does not provide good quantitative predictions. A good fit between the experimental data and the Trivedi and Laxmanan models is detected. The advantages of the Trivedi marginal stability analysis and the Laxmanan minimum dendrite tip undercooling approaches are discussed.

  12. A critical examination of the dendrite growth models Comparison of theory with experimental data

    NASA Technical Reports Server (NTRS)

    Tewari, S. N.; Laxmanan, V.

    1987-01-01

    Three dendrite growth models for directionally solidified succinonitrile-acetone, succinonitrile-salol, aluminum-copper, and lead-paladium alloys are evaluated. The characteristics of the Burden and Hunt (1974) model, the Laxmanan (1985) model, and the Trivedi (1980) model are described. The dendrite tip temperature, tip radius, liquid composition, and primary arm spacing for the alloys are analyzed in terms of growth speed, alloy composition, and temperature gradient. It is observed that the Burden and Hunt model accurately predicts the proper behavior of the parameters, but does not provide good quantitative predictions. A good fit between the experimental data and the Trivedi and Laxmanan models is detected. The advantages of the Trivedi marginal stability analysis and the Laxmanan minimum dendrite tip undercooling approaches are discussed.

  13. Dendritic Growth Investigators

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Representatives of NASA materials science experiments supported the NASA exhibit at the Rernselaer Polytechnic Institute's Space Week activities, April 5 through 11, 1999. From left to right are: Angie Jackman, project manager at NASA's Marshall Space Flight Center for dendritic growth experiments; Dr. Martin Glicksman of Rennselaer Polytechnic Instutute, Troy, NY, principal investigator on the Isothermal Dendritic Growth Experiment (IDGE) that flew three times on the Space Shuttle; and Dr. Matthew Koss of College of the Holy Cross in Worcester, MA, a co-investigator on the IDGE and now principal investigator on the Transient Dendritic Solidification Experiment being developed for the International Space Station (ISS). The image at far left is a dendrite grown in Glicksman's IDGE tests aboard the Shuttle. Glicksman is also principal investigator for the Evolution of Local Microstructures: Spatial Instabilities of Coarsening Clusters.

  14. OTEC Anchors: Selection and Plan for Development.

    DTIC Science & Technology

    1977-12-01

    Anchor systems capable of maintaining the Ocean Thermal Energy Conversion ( OTEC ) power plants on station were identified and compared. Deadweight...for OTEC , however, is probably not necessary because it is expected that such hard seafloor anchor sites are best avoided by OTEC plants. A plan for...structural analysis and design technique for the anchor, and finally a demonstration of a near prototype size OTEC free-fall deadweight anchor in early 1980. (Author)

  15. Anchors Aweigh: A Demonstration of Cross-Modality Anchoring and Magnitude Priming

    ERIC Educational Resources Information Center

    Oppenheimer, Daniel M.; LeBoeuf, Robyn A.; Brewer, Noel T.

    2008-01-01

    Research has shown that judgments tend to assimilate to irrelevant "anchors." We extend anchoring effects to show that anchors can even operate across modalities by, apparently, priming a general sense of magnitude that is not moored to any unit or scale. An initial study showed that participants drawing long "anchor" lines made higher numerical…

  16. 30 CFR 57.19002 - Anchoring.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Anchoring. 57.19002 Section 57.19002 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....19002 Anchoring. Hoists shall be anchored securely. ...

  17. 30 CFR 57.19002 - Anchoring.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Anchoring. 57.19002 Section 57.19002 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....19002 Anchoring. Hoists shall be anchored securely. ...

  18. 30 CFR 57.7032 - Anchoring.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Anchoring. 57.7032 Section 57.7032 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Drilling-Underground Only § 57.7032 Anchoring. Columns and the drills mounted on them shall be anchored...

  19. 30 CFR 57.19002 - Anchoring.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Anchoring. 57.19002 Section 57.19002 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....19002 Anchoring. Hoists shall be anchored securely. ...

  20. 30 CFR 56.19002 - Anchoring.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Anchoring. 56.19002 Section 56.19002 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Anchoring. Hoists shall be anchored securely. ...

  1. 30 CFR 56.19002 - Anchoring.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Anchoring. 56.19002 Section 56.19002 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Anchoring. Hoists shall be anchored securely. ...

  2. 30 CFR 57.7032 - Anchoring.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Anchoring. 57.7032 Section 57.7032 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Drilling-Underground Only § 57.7032 Anchoring. Columns and the drills mounted on them shall be anchored...

  3. 30 CFR 57.7032 - Anchoring.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Anchoring. 57.7032 Section 57.7032 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Drilling-Underground Only § 57.7032 Anchoring. Columns and the drills mounted on them shall be anchored...

  4. 30 CFR 57.19002 - Anchoring.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Anchoring. 57.19002 Section 57.19002 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....19002 Anchoring. Hoists shall be anchored securely. ...

  5. 30 CFR 56.19002 - Anchoring.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Anchoring. 56.19002 Section 56.19002 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Anchoring. Hoists shall be anchored securely. ...

  6. 30 CFR 57.7032 - Anchoring.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Anchoring. 57.7032 Section 57.7032 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Drilling-Underground Only § 57.7032 Anchoring. Columns and the drills mounted on them shall be anchored...

  7. 30 CFR 56.19002 - Anchoring.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Anchoring. 56.19002 Section 56.19002 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Anchoring. Hoists shall be anchored securely. ...

  8. 30 CFR 57.19002 - Anchoring.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Anchoring. 57.19002 Section 57.19002 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND....19002 Anchoring. Hoists shall be anchored securely. ...

  9. 30 CFR 56.19002 - Anchoring.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Anchoring. 56.19002 Section 56.19002 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Anchoring. Hoists shall be anchored securely. ...

  10. 33 CFR 401.15 - Stern anchors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Stern anchors. 401.15 Section 401... TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Condition of Vessels § 401.15 Stern anchors. (a) Every... equipped with a stern anchor. (b) Every integrated tug and barge or articulated tug and barge unit greater...

  11. 24 CFR 3285.401 - Anchoring instructions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... wind by use of anchor assembly type installations or by connecting the home to an alternative foundation system. See § 3285.301. (b) For anchor assembly type installations, the installation instructions... instructions and design for anchor type assemblies must be prepared by a registered professional engineer or...

  12. ADHD: Tips to Try

    MedlinePlus

    ... Right Sport for You Healthy School Lunch Planner ADHD: Tips to Try KidsHealth > For Teens > ADHD: Tips to Try Print A A A en español TDAH: Consejos que puedes probar ADHD , or attention deficit hyperactivity disorder, is a medical ...

  13. Total Telephone Tips.

    ERIC Educational Resources Information Center

    Corder, Lloyd E.; And Others

    This manual of telephone behavior tips for business and sales professionals offers ways to handle the disgruntled caller and makes suggestions on topics relevant to the telephone. The manual is divided into the following sections and subsections: (1) Common Courtesy (staff tips, answering the telephone, screening calls, transferring calls, taking…

  14. Southwestern Pine Tip Moth

    Treesearch

    Daniel T. Jennings; Robert E. Stevens

    1982-01-01

    The southwestern pine tip moth, Rhyacionia neomexicana (Dyar), injures young ponderosa pines (Pinus ponderosa Dougl. ex Laws) in the Southwest, central Rockies, and midwestern plains. Larvae feed on and destroy new, expanding shoots, often seriously reducing terminal growth of both naturally regenerated and planted pines. The tip moth is especially damaging to trees on...

  15. Macrosegregation During Dendritic Arrayed Growth of Hypoeutectic Pb-Sn Alloys: Influence of Primary Arm Spacing and Mushy Zone Length

    NASA Technical Reports Server (NTRS)

    Tewari, S. N.; Shah, R.

    1996-01-01

    Thermosolutal convection in the dendritic mushy zone occurs during directional solidification of hypoeutectic lead tin alloys in a positive thermal gradient, with the melt on the top and the solid below. This results in macrosegregation along the length of the solidified samples. The extent of macrosegregation increases with increasing primary dendrite spacings for constant mushy zone length. For constant primary spacings, the macrosegregation increases with decreasing mushy zone length. Presence of convection reduces the primary dendrite spacings. However, convection in the interdendritic melt has significantly more influence on the spacings as compared with that in the overlying melt, which is caused by the solutal buildup at the dendrite tips.

  16. Dendritic Growth with Fluid Flow for Pure Materials

    NASA Technical Reports Server (NTRS)

    Jeong, Jun-Ho; Dantzig, Jonathan A.; Goldenfeld, Nigel

    2003-01-01

    We have developed a three-dimensional, adaptive, parallel finite element code to examine solidification of pure materials under conditions of forced flow. We have examined the effect of undercooling, surface tension anisotropy and imposed flow velocity on the growth. The flow significantly alters the growth process, producing dendrites that grow faster, and with greater tip curvature, into the flow. The selection constant decreases slightly with flow velocity in our calculations. The results of the calculations agree well with the transport solution of Saville and Beaghton at high undercooling and high anisotropy. At low undercooling, significant deviations are found. We attribute this difference to the influence of other parts of the dendrite, removed from the tip, on the flow field.

  17. Biophysical characterization of the type III secretion tip proteins and the tip proteins attached to bacterium-like particles.

    PubMed

    Choudhari, Shyamal P; Chen, Xiaotong; Kim, Jae Hyun; Van Roosmalen, Maarten L; Greenwood, Jamie C; Joshi, Sangeeta B; Picking, William D; Leenhouts, Kees; Middaugh, C Russell; Picking, Wendy L

    2015-02-01

    Bacterium-like particles (BLPs), derived from Lactococcus lactis, offer a self-adjuvanting delivery vehicle for subunit protein vaccines. Proteins can be specifically loaded onto the BLPs via a peptidoglycan anchoring (PA) domain. In this study, the tip proteins IpaD, SipD, and LcrV belonging to type III secretion systems of Shigella flexneri, Salmonella enterica, and Yersinia enterocolitica, respectively, were fused to the PA and loaded onto the BLPs. Herein, we biophysically characterized these nine samples and condensed the spectroscopic results into three-index empirical phase diagrams (EPDs). The EPDs show distinctions between the IpaD/SipD and LcrV subfamilies of tip proteins, based on their physical stability, even upon addition of the PA. Upon attachment to the BLPs, the BLPs become defining moiety in the spectroscopic measurements, leaving the tip proteins to have a subtle yet modulating effect on the structural integrity of the tip proteins-BLPs binding. In summary, this work provides a comprehensive view of physical stability of the tip proteins and tip protein-BLPs and serves as a baseline for screening of excipients to increase the stability of the tip protein-BLPs for future vaccine formulation.

  18. Biophysical Characterization of the Type III Secretion Tip Proteins and the Tip Proteins Attached to Bacterium-Like Particles

    PubMed Central

    Choudhari, Shyamal P.; Chen, Xiaotong; Kim, Jae Hyun; van Roosmalen, Maarten L.; Greenwood, Jamie C.; Joshi, Sangeeta B.; Picking, William D.; Leenhouts, Kees; Middaugh, C. Russell; Picking, Wendy L.

    2014-01-01

    Bacterium-like particles (BLPs), derived from Lactococcus lactis, offer a self-adjuvanting delivery vehicle for subunit protein vaccines. Proteins can be specifically loaded onto the BLPs via a peptidoglycan anchoring domain (PA). In this study, the tip proteins IpaD, SipD and LcrV belonging to type three secretion systems of Shigella flexneri, Salmonella enterica and Yersinia enterocolitica, respectively, were fused to the PA and loaded onto the BLPs. Herein, we biophysically characterized these nine samples and condensed the spectroscopic results into three-index empirical phase diagrams (EPDs). The EPDs show distinctions between the IpaD/SipD and LcrV subfamilies of tip proteins, based on their physical stability, even upon addition of the PA. Upon attachment to the BLPs, the BLPs become defining moiety in the spectroscopic measurements, leaving the tip proteins to have a subtle yet modulating effect on the structural integrity of the tip proteins-BLPs binding. In summary, this work provides a comprehensive view of physical stability of the tip proteins and tip protein-BLPs and serves as a baseline for screening of excipients to increase the stability of the tip protein-BLPs for future vaccine formulation. PMID:24916512

  19. Shape Parameter for a Non-Axisymmetric Isothermal Dendrite

    NASA Technical Reports Server (NTRS)

    McFadden, G. B.; Coriell, S. R.; Sekerka, R. F.

    1999-01-01

    In previous work, we found approximate solutions for paraboloids having perturbations with four-fold axial symmetry in order to model dendritic growth in cubic materials. These solutions provide self-consistent corrections through second order in a shape parameter e to the Peclet number-supercooling relation of the Ivantsov solution. The parameter e is proportional to the amplitude of the four-fold correction to the dendrite shape, as measured from the Ivantsov paraboloid of revolution. We calculate e by comparing the dendrite tip shape to the portion of the equilibrium shape near the growth direction, (001), for anisotropic surface free energy, where the ni are components of the unit normal of the crystal surface. This comparison results in epsilon = -2(epsilon 4), independent of the Peclet number. From the experimental value of epsilon 4, we find epsilon approximately 0.011, in good agreement with the measured value epsilon approximately 0.008 of LaCombe et al.

  20. Shape Parameter for a Non-Axisymmetric Isothermal Dendrite

    NASA Technical Reports Server (NTRS)

    McFadden, G. B.; Coriell, S. R.; Sekerka, R. F.

    1999-01-01

    In previous work, we found approximate solutions for paraboloids having perturbations with four-fold axial symmetry in order to model dendritic growth in cubic materials. These solutions provide self-consistent corrections through second order in a shape parameter e to the Peclet number-supercooling relation of the Ivantsov solution. The parameter e is proportional to the amplitude of the four-fold correction to the dendrite shape, as measured from the Ivantsov paraboloid of revolution. We calculate e by comparing the dendrite tip shape to the portion of the equilibrium shape near the growth direction, (001), for anisotropic surface free energy, where the ni are components of the unit normal of the crystal surface. This comparison results in epsilon = -2(epsilon 4), independent of the Peclet number. From the experimental value of epsilon 4, we find epsilon approximately 0.011, in good agreement with the measured value epsilon approximately 0.008 of LaCombe et al.

  1. The ROSETTA Lander anchoring system

    NASA Astrophysics Data System (ADS)

    Thiel, Markus; Stöcker, Jakob; Rohe, Christian; Kömle, Norbert I.; Kargl, Günter; Hillenmaier, Olaf; Lell, Peter

    2003-09-01

    A major goal of the ESA cornerstone mission ROSETTA is to land a package of scientific instruments known as the ROSETTA Lander on the nucleus of a comet. Due to the low gravity a highly reliable fixation of the ROSETTA Lander to the target comet 67P/Churyumov-Gerasimenko (3rd) is essential. For that purpose a redundant Anchoring System, consisting of two pyrotechnically actuated Anchoring Harpoons and a redundant Control Electronics has been developed, built and qualified at the Max-Planck-Institut für extraterrestrische Physik (MPE), Garching. The pyrotechnical gas generator has been developed jointly by Pyroglobe GmbH and MPE, the procurement of the control electronics has been sub-contracted to Magson GmbH, Berlin. A study to obtain a suitable lubrication method for the commutator of a brushed DC motor has been conducted at the European Space Tribology Laboratory (ESTL; S. D. Lewis et al., 2003).

  2. Anchoring bias in online voting

    NASA Astrophysics Data System (ADS)

    Yang, Zimo; Zhang, Zi-Ke; Zhou, Tao

    2012-12-01

    Voting online with explicit ratings could largely reflect people's preferences and objects' qualities, but ratings are always irrational, because they may be affected by many unpredictable factors like mood, weather and other people's votes. By analyzing two real systems, this paper reveals a systematic bias embedding in the individual decision-making processes, namely people tend to give a low rating after a low rating, as well as a high rating following a high rating. This so-called anchoring bias is validated via extensive comparisons with null models, and numerically speaking, the extent of bias decays with voting interval in a logarithmic form. Our findings could be applied in the design of recommender systems and considered as important complementary materials to previous knowledge about anchoring effects on financial trades, performance judgments, auctions, and so on.

  3. Anchoring in Numeric Judgments of Visual Stimuli

    PubMed Central

    Langeborg, Linda; Eriksson, Mårten

    2016-01-01

    This article investigates effects of anchoring in age estimation and estimation of quantities, two tasks which to different extents are based on visual stimuli. The results are compared to anchoring in answers to classic general knowledge questions that rely on semantic knowledge. Cognitive load was manipulated to explore possible differences between domains. Effects of source credibility, manipulated by differing instructions regarding the selection of anchor values (no information regarding anchor selection, information that the anchors are randomly generated or information that the anchors are answers from an expert) on anchoring were also investigated. Effects of anchoring were large for all types of judgments but were not affected by cognitive load or by source credibility in either one of the researched domains. A main effect of cognitive load on quantity estimations and main effects of source credibility in the two visually based domains indicate that the manipulations were efficient. Implications for theoretical explanations of anchoring are discussed. In particular, because anchoring did not interact with cognitive load, the results imply that the process behind anchoring in visual tasks is predominantly automatic and unconscious. PMID:26941684

  4. Anchoring in Numeric Judgments of Visual Stimuli.

    PubMed

    Langeborg, Linda; Eriksson, Mårten

    2016-01-01

    This article investigates effects of anchoring in age estimation and estimation of quantities, two tasks which to different extents are based on visual stimuli. The results are compared to anchoring in answers to classic general knowledge questions that rely on semantic knowledge. Cognitive load was manipulated to explore possible differences between domains. Effects of source credibility, manipulated by differing instructions regarding the selection of anchor values (no information regarding anchor selection, information that the anchors are randomly generated or information that the anchors are answers from an expert) on anchoring were also investigated. Effects of anchoring were large for all types of judgments but were not affected by cognitive load or by source credibility in either one of the researched domains. A main effect of cognitive load on quantity estimations and main effects of source credibility in the two visually based domains indicate that the manipulations were efficient. Implications for theoretical explanations of anchoring are discussed. In particular, because anchoring did not interact with cognitive load, the results imply that the process behind anchoring in visual tasks is predominantly automatic and unconscious.

  5. Thermodynamic-kinetic simulation of constrained dendrite growth in steels

    SciTech Connect

    Miettinen, J.

    2000-04-01

    A model of constrained dendritic growth for steels, based on thermodynamic and kinetic theory, is presented. The model links thermodynamic chemical potential-equality equations to an existing, approximate treatment of constrained dendritic growth in multicomponent steels, taking into account the deviation from the local thermodynamic equilibrium of the phase interface caused by interface friction, capillarity, and solute trapping. Due to the thermodynamic approach, with a thermodynamic model and recently assessed data, the present treatment yields a more accurate determination of phase stabilities than the earlier methods. Depending on the steel composition and the growth conditions (growth rate and temperature gradient), the model determines the dendrite tip undercooling, the primary solid phase (ferrite or austenite), the stability of that phase, certain dimensions of the microstructure, and the solute accumulation ahead of the dendrite tip. A special optional calculations is that of the equally probable formation of ferrite and austenite in stainless steels. Calculations for testing the model and for validation it with experimental data are presented.

  6. Anchor for Fiberglas Guy Rod

    NASA Technical Reports Server (NTRS)

    Wilson, A. H.

    1982-01-01

    Solution to problem of anchoring fiberglas guy rods to install nut with threads on outer circumference, followed by aluminum sleeve. Sleeve has opening oval at upper and round at bottom end. End of rod is split so fiberglas wedge can be inserted to form V-shaped end. Spread end of rod fits into tapered hole in sleeve and threaded aluminum coupling is put over rod and sleeve.

  7. Holding Capacity of Plate Anchors

    DTIC Science & Technology

    1980-10-01

    Engineering Laboratory, Technical Note N-1545. Port Hueneme, Calif., Jan 1979. 4 safe arm device gun barrel reaction vessel Figure 1-2. CEL 20K propell...anchors in cohesive soils, Civil Engineering Laboratory, Technical Note N-1545. Port Hueneme, Calif., Jan 1979. Berger, W. H., and E. L. Winterer...NORTHWESTERN UNIV Z.P. Bazant Evanston IL NY CITY COMMUNITY COLLEGE BROOKLYN, NY (LIBRARY) NYS ENERGY OFFICE Library, Albany NY OREGON STATE UNIVERSITY (CE

  8. Independent control of polar and azimuthal anchoring.

    PubMed

    Anquetil-Deck, C; Cleaver, D J; Bramble, J P; Atherton, T J

    2013-07-01

    Monte Carlo simulation, experiment, and continuum theory are used to examine the anchoring exhibited by a nematic liquid crystal at a patterned substrate comprising a periodic array of rectangles that, respectively, promote vertical and planar alignment. It is shown that the easy axis and effective anchoring energy promoted by such surfaces can be readily controlled by adjusting the design of the pattern. The calculations reveal rich behavior: for strong anchoring, as exhibited by the simulated system, for rectangle ratios ≥2 the nematic aligns in the direction of the long edge of the rectangles, the azimuthal anchoring coefficient changing with pattern shape. In weak anchoring scenarios, however, including our experimental systems, preferential anchoring is degenerate between the two rectangle diagonals. Bistability between diagonally aligned and edge-aligned arrangement is predicted for intermediate combinations of anchoring coefficient and system length scale.

  9. Fluid flow and pattern selection in dendritic growth - Ground based in situ observation

    NASA Astrophysics Data System (ADS)

    Huang, Tao; Liu, Shan; Lu, Deyang; Zhou, Yaohe; Cheng, Gongshan

    1989-02-01

    Model experiments on fluid flow and pattern selection have been done by creating flow in liquid regions close to the growth fronts in dendritic growth of SCN-aceton dilute alloys. The kinetics and morphology of dendritic growth were measured as a function of thermal gradient, growth velocity, and flow velocity. The present paper provides the first study of convection effects on constrained dendritic and cellular growth which focuses on the tip morphology and develops a boundary layer analysis. All of the problems addressed have application to the interpretation of the experimental phenomena arising from solidification and fluid dynamics on earth and in a space laboratory.

  10. AKAP-anchored PKA maintains neuronal L-type calcium channel activity and NFAT transcriptional signaling.

    PubMed

    Murphy, Jonathan G; Sanderson, Jennifer L; Gorski, Jessica A; Scott, John D; Catterall, William A; Sather, William A; Dell'Acqua, Mark L

    2014-06-12

    L-type voltage-gated Ca2+ channels (LTCC) couple neuronal excitation to gene transcription. LTCC activity is elevated by the cyclic AMP (cAMP)-dependent protein kinase (PKA) and depressed by the Ca2+-dependent phosphatase calcineurin (CaN), and both enzymes are localized to the channel by A-kinase anchoring protein 79/150 (AKAP79/150). AKAP79/150 anchoring of CaN also promotes LTCC activation of transcription through dephosphorylation of the nuclear factor of activated T cells (NFAT). We report here that the basal activity of AKAP79/150-anchored PKA maintains neuronal LTCC coupling to CaN-NFAT signaling by preserving LTCC phosphorylation in opposition to anchored CaN. Genetic disruption of AKAP-PKA anchoring promoted redistribution of the kinase out of postsynaptic dendritic spines, profound decreases in LTCC phosphorylation and Ca2+ influx, and impaired NFAT movement to the nucleus and activation of transcription. Thus, LTCC-NFAT transcriptional signaling in neurons requires precise organization and balancing of PKA and CaN activities in the channel nanoenvironment, which is only made possible by AKAP79/150 scaffolding.

  11. AKAP-Anchored PKA Maintains Neuronal L-type Calcium Channel Activity and NFAT Transcriptional Signaling

    PubMed Central

    Murphy, Jonathan G.; Sanderson, Jennifer L.; Gorski, Jessica A.; Scott, John D.; Catterall, William A.; Sather, William A.; Dell’Acqua, Mark L.

    2014-01-01

    Summary In neurons, Ca2+ influx through L-type voltage-gated Ca2+ channels (LTCC) couples electrical activity to changes in transcription. LTCC activity is elevated by the cAMP-dependent protein kinase (PKA) and depressed by the Ca2+-dependent phosphatase calcineurin (CaN), with both enzymes localized to the channel by A-kinase anchoring protein (AKAP) 79/150. AKAP79/150 anchoring of CaN also promotes LTCC activation of transcription through dephosphorylation of the nuclear factor of activated T-cells (NFAT). We report here that genetic disruption of PKA anchoring to AKAP79/150 also interferes with LTCC activation of CaN-NFAT signaling in neurons. Disruption of AKAP-PKA anchoring promoted redistribution of the kinase out of dendritic spines, profound decreases in LTCC phosphorylation and Ca2+ influx, and impaired NFAT movement to the nucleus and activation of transcription. Our findings support a model wherein basal activity of AKAP79/150-anchored PKA opposes CaN to preserve LTCC phosphorylation, thereby sustaining LTCC activation of CaN-NFAT signaling to the neuronal nucleus. PMID:24835999

  12. Modeling of coupled motion and growth interaction of equiaxed dendritic crystals in a binary alloy during solidification

    NASA Astrophysics Data System (ADS)

    Qi, Xin Bo; Chen, Yun; Kang, Xiu Hong; Li, Dian Zhong; Gong, Tong Zhao

    2017-03-01

    Motion of growing dendrites is a common phenomenon during solidification but often neglected in numerical simulations because of the complicate underlying multiphysics. Here a phase-field model incorporating dendrite-melt two-phase flow is proposed for simulating the dynamically interacted process. The proposed model circumvents complexity to resolve dendritic growth, natural convection and solid motion simultaneously. Simulations are performed for single and multiple dendritic growth of an Al-based alloy in a gravity environment. Computing results of an isolated dendrite settling down in the convective supersaturated melt shows that solid motion is able to overwhelm solutal convection and causes a rather different growth morphology from the stationary dendrite that considers natural convection alone. The simulated tip growth dynamics are correlated with a modified boundary layer model in the presence of melt flow, which well accounts for the variation of tip velocity with flow direction. Polycrystalline simulations reveal that the motion of dendrites accelerates the occurrence of growth impingement which causes the behaviors of multiple dendrites are distinct from that of single dendrite, including growth dynamics, morphology evolution and movement path. These polycrystalline simulations provide a primary understanding of the sedimentation of crystals and resulting chemical homogeneity in industrial ingots.

  13. Modeling of coupled motion and growth interaction of equiaxed dendritic crystals in a binary alloy during solidification

    PubMed Central

    Qi, Xin Bo; Chen, Yun; Kang, Xiu Hong; Li, Dian Zhong; Gong, Tong Zhao

    2017-01-01

    Motion of growing dendrites is a common phenomenon during solidification but often neglected in numerical simulations because of the complicate underlying multiphysics. Here a phase-field model incorporating dendrite-melt two-phase flow is proposed for simulating the dynamically interacted process. The proposed model circumvents complexity to resolve dendritic growth, natural convection and solid motion simultaneously. Simulations are performed for single and multiple dendritic growth of an Al-based alloy in a gravity environment. Computing results of an isolated dendrite settling down in the convective supersaturated melt shows that solid motion is able to overwhelm solutal convection and causes a rather different growth morphology from the stationary dendrite that considers natural convection alone. The simulated tip growth dynamics are correlated with a modified boundary layer model in the presence of melt flow, which well accounts for the variation of tip velocity with flow direction. Polycrystalline simulations reveal that the motion of dendrites accelerates the occurrence of growth impingement which causes the behaviors of multiple dendrites are distinct from that of single dendrite, including growth dynamics, morphology evolution and movement path. These polycrystalline simulations provide a primary understanding of the sedimentation of crystals and resulting chemical homogeneity in industrial ingots. PMID:28361933

  14. Modeling of coupled motion and growth interaction of equiaxed dendritic crystals in a binary alloy during solidification.

    PubMed

    Qi, Xin Bo; Chen, Yun; Kang, Xiu Hong; Li, Dian Zhong; Gong, Tong Zhao

    2017-03-31

    Motion of growing dendrites is a common phenomenon during solidification but often neglected in numerical simulations because of the complicate underlying multiphysics. Here a phase-field model incorporating dendrite-melt two-phase flow is proposed for simulating the dynamically interacted process. The proposed model circumvents complexity to resolve dendritic growth, natural convection and solid motion simultaneously. Simulations are performed for single and multiple dendritic growth of an Al-based alloy in a gravity environment. Computing results of an isolated dendrite settling down in the convective supersaturated melt shows that solid motion is able to overwhelm solutal convection and causes a rather different growth morphology from the stationary dendrite that considers natural convection alone. The simulated tip growth dynamics are correlated with a modified boundary layer model in the presence of melt flow, which well accounts for the variation of tip velocity with flow direction. Polycrystalline simulations reveal that the motion of dendrites accelerates the occurrence of growth impingement which causes the behaviors of multiple dendrites are distinct from that of single dendrite, including growth dynamics, morphology evolution and movement path. These polycrystalline simulations provide a primary understanding of the sedimentation of crystals and resulting chemical homogeneity in industrial ingots.

  15. Molecular architecture of synaptic actin cytoskeleton in hippocampal neurons reveals a mechanism of dendritic spine morphogenesis.

    PubMed

    Korobova, Farida; Svitkina, Tatyana

    2010-01-01

    Excitatory synapses in the brain play key roles in learning and memory. The formation and functions of postsynaptic mushroom-shaped structures, dendritic spines, and possibly of presynaptic terminals, rely on actin cytoskeleton remodeling. However, the cytoskeletal architecture of synapses remains unknown hindering the understanding of synapse morphogenesis. Using platinum replica electron microscopy, we characterized the cytoskeletal organization and molecular composition of dendritic spines, their precursors, dendritic filopodia, and presynaptic boutons. A branched actin filament network containing Arp2/3 complex and capping protein was a dominant feature of spine heads and presynaptic boutons. Surprisingly, the spine necks and bases, as well as dendritic filopodia, also contained a network, rather than a bundle, of branched and linear actin filaments that was immunopositive for Arp2/3 complex, capping protein, and myosin II, but not fascin. Thus, a tight actin filament bundle is not necessary for structural support of elongated filopodia-like protrusions. Dynamically, dendritic filopodia emerged from densities in the dendritic shaft, which by electron microscopy contained branched actin network associated with dendritic microtubules. We propose that dendritic spine morphogenesis begins from an actin patch elongating into a dendritic filopodium, which tip subsequently expands via Arp2/3 complex-dependent nucleation and which length is modulated by myosin II-dependent contractility.

  16. Macrotransport-solidification kinetics modeling of equiaxed dendritic growth. Part 1: Model development and discussion

    SciTech Connect

    Nastac, L.; Stefanescu, D.M.

    1996-12-01

    An analytical model that describes solidification of equiaxed dendrites has been developed for use in solidification kinetics-macrotransport modeling. It relaxes some of the assumptions made in previous models, such as the Dustin-Kurz, Rappaz-Thevoz, and Kanetkar-Stefanescu models. It is assumed that nuclei grow as unperturbed spheres until the radius of the sphere becomes larger than the minimum radius of instability. Then, growth of the dendrites is related to morphological instability and is calculated as a function of melt undercooling around the dendrite tips, which is controlled by the bulk temperature and the intrinsic volume average concentration of the liquid phase. When the general morphology of equiaxed dendrites is considered, the evolution of the fraction of solid is related to the interdendritic branching and dynamic coarsening (through the evolution of the specific interfacial areas) and to the topology and movement of the dendrite envelope (through the tip growth velocity and dendrite shape factor). The particular case of this model is the model for globulitic an overall solute and thermal balance around a growing equiaxed dendrite grain within a spherical closed system. Overall solute balance in the integral form is obtained by a complete analytical solution of the diffusion field in both liquid and solid phases. The bulk temperature is obtained from the solution of the macrotransport-solidification kinetics problem.

  17. Root hairs aid soil penetration by anchoring the root surface to pore walls

    PubMed Central

    Bengough, A. Glyn; Loades, Kenneth; McKenzie, Blair M.

    2016-01-01

    The physical role of root hairs in anchoring the root tip during soil penetration was examined. Experiments using a hairless maize mutant (Zea mays: rth3–3) and its wild-type counterpart measured the anchorage force between the primary root of maize and the soil to determine whether root hairs enabled seedling roots in artificial biopores to penetrate sandy loam soil (dry bulk density 1.0–1.5g cm−3). Time-lapse imaging was used to analyse root and seedling displacements in soil adjacent to a transparent Perspex interface. Peak anchorage forces were up to five times greater (2.5N cf. 0.5N) for wild-type roots than for hairless mutants in 1.2g cm−3 soil. Root hair anchorage enabled better soil penetration for 1.0 or 1.2g cm−3 soil, but there was no significant advantage of root hairs in the densest soil (1.5g cm−3). The anchorage force was insufficient to allow root penetration of the denser soil, probably because of less root hair penetration into pore walls and, consequently, poorer adhesion between the root hairs and the pore walls. Hairless seedlings took 33h to anchor themselves compared with 16h for wild-type roots in 1.2g cm−3 soil. Caryopses were often pushed several millimetres out of the soil before the roots became anchored and hairless roots often never became anchored securely.The physical role of root hairs in anchoring the root tip may be important in loose seed beds above more compact soil layers and may also assist root tips to emerge from biopores and penetrate the bulk soil. PMID:26798027

  18. Active properties of neuronal dendrites.

    PubMed

    Johnston, D; Magee, J C; Colbert, C M; Cristie, B R

    1996-01-01

    Dendrites of neurons in the central nervous system are the principal sites for excitatory synaptic input. Although little is known about their function, two disparate perspectives have arisen to describe the activity patterns inherent to these diverse tree-like structures. Dendrites are thus considered either passive or active in their role in integrating synaptic inputs. This review follows the history of dendritic research from before the turn of the century to the present, with a primary focus on the hippocampus. A number of recent techniques, including high-speed fluorescence imaging and dendritic patch clamping, have provided new information and perspectives about the active properties of dendrites. The results support previous notions about the dendritic propagation of action potentials and also indicate which types of voltage-gated sodium and calcium channels are expressed and functionally active in dendrites. Possible roles for the active properties of dendrites in synaptic plasticity and integration are also discussed.

  19. Tips for Breastfeeding Moms

    MedlinePlus

    United States Department of Agriculture Tips for Breastfeeding Moms Making healthy food choices along with regular physical activity will keep you healthy while you breastfeed. Find Your Healthy Eating Style Choose ...

  20. Health Tips for Adults

    MedlinePlus

    ... clinical feasibility to large multi-center studies Funding Process Tips for applicants; grant review and management resources; and commonly used funding mechanisms, including diversity and small business programs Research Training & Career Development Grant programs for ...

  1. Eye Drop Tips

    MedlinePlus

    ... Involved News About Us Donate In This Section Eye Drop Tips en Español email Send this article ... the reach of children. Steps For Putting In Eye Drops: Start by tilting your head backward while ...

  2. Tips for Daily Life

    MedlinePlus

    ... date on the latest news and advances in Alzheimer's treatments, care and research. Get tips for living with ... What is dementia What is Alzheimer's Stages of Alzheimer's Treatments Contact us 24/7 Helpline: 1-800-272- ...

  3. Tips for Chronic Pain

    MedlinePlus

    Patient Education Sheet Tips for Chronic Pain The SSF thanks Stuart S. Kassan, MD, FACP, Clinical Professor of Medicine, University of Colorado Health Sciences Center, Denver, Colorado, for authoring ...

  4. Bed Bug Tips

    EPA Pesticide Factsheets

    How to deal with bed bugs in one printable page. Ten tips include ensuring correct insect identification, reducing clutter, understand integrated pest management, using mattress and box spring encasements, and heat treatment.

  5. Tips to Prevent Poisonings

    MedlinePlus

    ... and Resources STEADI Initiative for Health Care Providers Water-Related Injuries Get the Facts Publications Poisoning Tips ... containers. Do not use food containers such as cups, bottles, or jars to store chemical products such ...

  6. Tips from the Classroom.

    ERIC Educational Resources Information Center

    Epstein, Jim; Ashcraft, Nikki; Clarke, Paul M.; Wolf, Grant S.

    1999-01-01

    Four tips for use in the English-as-a-Second-Language classroom are highlighted: Mr. Bean in the Classroom; Defining Your Future; Coin Questions; Our Futures: Simple, Progressive, and Perfect. (Author/VWL)

  7. Tips for labor coaches

    MedlinePlus

    ... some tips for getting prepared. Before the big day Arrives Labor coaches should go to childbirth classes ... get through her labor and delivery. When the day Arrives You might be at the hospital for ...

  8. Insider conference tips

    NASA Astrophysics Data System (ADS)

    Tennant, Jill

    2012-01-01

    Attending an educator conference and its associated exhibit hall can be a rewarding experience for your brain. But if you keep in mind these insider's tips, your feet, arms, stomach, and wallet will also thank you.

  9. Dendritic Polymers for Theranostics

    PubMed Central

    Ma, Yuan; Mou, Quanbing; Wang, Dali; Zhu, Xinyuan; Yan, Deyue

    2016-01-01

    Dendritic polymers are highly branched polymers with controllable structures, which possess a large population of terminal functional groups, low solution or melt viscosity, and good solubility. Their size, degree of branching and functionality can be adjusted and controlled through the synthetic procedures. These tunable structures correspond to application-related properties, such as biodegradability, biocompatibility, stimuli-responsiveness and self-assembly ability, which are the key points for theranostic applications, including chemotherapeutic theranostics, biotherapeutic theranostics, phototherapeutic theranostics, radiotherapeutic theranostics and combined therapeutic theranostics. Up to now, significant progress has been made for the dendritic polymers in solving some of the fundamental and technical questions toward their theranostic applications. In this review, we briefly summarize how to control the structures of dendritic polymers, the theranostics-related properties derived from their structures and their theranostics-related applications. PMID:27217829

  10. Study of columnar-equiaxed transition and anaxial columnar dendrites growth of hypoeutectic alloy with synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Li, F. G.; Zhang, J.; Dong, Q.; Dai, Y. B.; Sun, B. D.; Xie, H. L.

    2013-10-01

    Among solidification processes, the columnar to equiaxed transition (CET) is critical component for formation either of microstructure or macrostructure. Directional solidification of Al-Cu alloy was performed at the BL13W beamline of Shanghai Synchrotron Radiation Facility (SSRF). The imaging results reveal that CET was provoked by external thermal disturbance. The fragment of dendrite tips were come from solute-rich-zone. And they floated to the mushy zone to form the equiaxed dendrites. As the conditions are suitable, a new dendrite morphology sprout and grow up, in which dendrites grow along <110> directions in a binary Al-Cu alloy. These dendrites have no obvious primary arms and were named anaxial columnar dendrites.

  11. Dendritic Release of Neurotransmitters.

    PubMed

    Ludwig, Mike; Apps, David; Menzies, John; Patel, Jyoti C; Rice, Margaret E

    2016-12-06

    Release of neuroactive substances by exocytosis from dendrites is surprisingly widespread and is not confined to a particular class of transmitters: it occurs in multiple brain regions, and includes a range of neuropeptides, classical neurotransmitters, and signaling molecules, such as nitric oxide, carbon monoxide, ATP, and arachidonic acid. This review is focused on hypothalamic neuroendocrine cells that release vasopressin and oxytocin and midbrain neurons that release dopamine. For these two model systems, the stimuli, mechanisms, and physiological functions of dendritic release have been explored in greater detail than is yet available for other neurons and neuroactive substances. © 2017 American Physiological Society. Compr Physiol 7:235-252, 2017.

  12. Lithium Dendrite Formation

    SciTech Connect

    2015-03-06

    Scientists at the Department of Energy’s Oak Ridge National Laboratory have captured the first real-time nanoscale images of lithium dendrite structures known to degrade lithium-ion batteries. The ORNL team’s electron microscopy could help researchers address long-standing issues related to battery performance and safety. Video shows annular dark-field scanning transmission electron microscopy imaging (ADF STEM) of lithium dendrite nucleation and growth from a glassy carbon working electrode and within a 1.2M LiPF6 EC:DM battery electrolyte.

  13. Isothermal Dendritic Growth Experiment Video

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This video, captured during the Isothermal Dendritic Growth Experiment (IDGE) flown on STS-87 as a part of the fourth United States Microgravity payload, shows the growth of a dendrite, and the surface solidification that occurred on the front and back windows of the growth chamber. Dendrites are tiny, tree like structures that form as metals solidify.

  14. Synaptogenesis and synaptic protein localization in the postnatal development of rod bipolar cell dendrites in mouse retina.

    PubMed

    Anastassov, Ivan A; Wang, Weiwei; Dunn, Felice A

    2017-05-25

    Retinal responses to photons originate in rod photoreceptors and are transmitted to the ganglion cell output of the retina through the primary rod bipolar pathway. At the first synapse of this pathway, input from multiple rods is pooled into individual rod bipolar cells. This architecture is called convergence. Convergence serves to improve sensitivity of rod vision when photons are sparse. Establishment of convergence depends on the development of a proper complement of dendritic tips and transduction proteins in rod bipolar cells. How the dendrites of rod bipolar cells develop and contact the appropriate number of rods is unknown. To answer this question we visualized individual rod bipolar cells in mouse retina during postnatal development and quantified the number of dendritic tips, as well as the expression of transduction proteins within dendrites. Our findings show that the number of dendritic tips in rod bipolar cells increases monotonically during development. The number of tips at P21, P30, and P82 exceeds the previously reported rod convergence ratios, and the majority of these tips are proximal to a presynaptic rod release site, suggesting more rods provide input to a rod bipolar cell. We also show that dendritic transduction cascade members mGluR6 and TRPM1 appear in tips with different timelines. These finding suggest that (a) rod bipolar cell dendrites elaborate without pruning during development, (b) the convergence ratio between rods and rod bipolar cells may be higher than previously reported, and (c) mGluR6 and TRPM1 are trafficked independently during development. © 2017 Wiley Periodicals, Inc.

  15. EBSD Characterization of Dendrites in Synthetic and Natural Rocks

    NASA Astrophysics Data System (ADS)

    Hammer, J. E.; Tiley, J.; Shiveley, A.; Knox, S.; Viswanathan, G.

    2011-12-01

    Arborescent crystals in igneous rocks are associated with extreme crystallization environments: the protoplanary disk (chondrules), Earth's ultramafic Archean mantle (komatiite), and terrestrial submarine-erupted lavas (pillow basalts), although the role of morphological instabilities in more mundane settings such as magma reservoirs of modern oceanic islands is increasingly appreciated (see Welsch et al., V16). Fundamentals of dendrite formation are presumably well understood: branching morphologies belie crystal growth conditions in which the driving force for solidification produces a kinetic roughening transition, transforming an atomically smooth crystal-liquid interface into a rough, adhesive interface capable of extremely rapid advancement. However, not since photomicrograhic advances made possible close observations of snow crystals (Nakaya 1936), has there been a more promising set of analytical tools to characterize dendrites in natural and synthetic materials in pursuit of new insights. We are investigating clinopyroxene (cpx) in the quenched top of Fe-rich tholeiitic lava (Munro Township, Northeast Ontario; Fig. 1) and a synthetic basalt of similar character (Hammer 2006) with electron backscatter diffraction (EBSD), 3D reconstruction of optical serial sections, and TEM. Here we report intriguing phenomena observed with EBSD common to both samples. Severe thinning of dendrite trunks and repeated tip splitting destroys the self-similarity associated with classical dendrites and instead presages 'seaweed' morphology. Split tips manifest incremental trajectory deflections, producing gently arched trunks (Fig. 1A) as well as tightly curved (r<10 um) trunks. Crystals progressively rotate clockwise about cpx <010>, producing distinctive misorientation maps and pole figures (Fig. 1C). Parallel branches exhibit similar rotational trajectories, carving parallel arcs in the <010> pole figure. The high incidence of side branching and tip splitting is consistent

  16. Mussel-inspired dendritic polymers as universal multifunctional coatings.

    PubMed

    Wei, Qiang; Achazi, Katharina; Liebe, Hendrik; Schulz, Andrea; Noeske, Paul-Ludwig Michael; Grunwald, Ingo; Haag, Rainer

    2014-10-20

    A rapid and universal approach for multifunctional material coatings was developed based on a mussel-inspired dendritic polymer. This new kind of polymer mimics not only the functional groups of mussel foot proteins (mfps) but also their molecular weight and molecular structure. The large number of catechol and amine groups set the basis for heteromultivalent anchoring and crosslinking. The molecular weight reaches 10 kDa, which is similar to the most adhesive mussel foot protein mfp-5. Also, the dendritic structure exposes its functional groups on the surface like the folded proteins. As a result, a very stable coating can be prepared on virtually any type of material surface within 10 min by a simple dip-coating method, which is as fast as the formation of mussel byssal threads in nature. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Data and Modeling of Dendrites Subject to A Step Change in Pressure (TDSE)

    NASA Technical Reports Server (NTRS)

    Koss, Matthew B.; LaCombe, J. C.; Glicksman, M. E.; Pines, V.; Chait, A.

    2003-01-01

    There is considerable interest in dendritic solidification because of the influence dendrites have in the determination of microstructure, and thereby in the physical properties of cast metals and alloys. Current theories and models of dendritic growth generally couple diffusion effects in the melt with the physics of the interface. Data and subsequent analysis prior of the tip growth speed and radii of thermal succinonitrile dendrites in the near-convection free, on-orbit, free-fall environment demonstrate that these theories yield predictions that are reasonably in agreement with the results of experiment. However, data and analysis for assessing the interfacial physics component of theory are not sufficiently detailed or definitive. To study fundamental aspects of dendritic interface stability, we are measuring and modeling the kinetics and morphology of dendrites as they evolve from one well-defined steady state at a pre-set supercooling, through a transient stage, to a different well-defined steady state. More specifically, we subject succinonitrile dendrites, growing under steady-state conditions, to a rapid change in pressure. This leads to a rapid change in thermal driving force from the corresponding change in both the equilibrium melting temperature due to the Clapeyron effect, and a change in the far-field temperature due to adiabatic temperature changes in the bulk liquid and solid. Subsequently, we observe transformations from a well-characterized initial state into a new steady-state. Initial data reveal that the dendrite tip velocity changes almost as fast as the pressure charges, while the tip radius changes occur more slowly, taking from 10 60 seconds depending on the size of the step change and the final supercooling. Computer modeling of this process shows both agreements and disagreements with the experimental data. In making these observations and measurements, we are gaining new understandings of interfacial dynamics and state

  18. Carbon-fiber tips for scanning probe microscopes and molecular electronics experiments.

    PubMed

    Rubio-Bollinger, Gabino; Castellanos-Gomez, Andres; Bilan, Stefan; Zotti, Linda A; Arroyo, Carlos R; Agraït, Nicolás; Cuevas, Juan Carlos

    2012-05-15

    We fabricate and characterize carbon-fiber tips for their use in combined scanning tunneling and force microscopy based on piezoelectric quartz tuning fork force sensors. An electrochemical fabrication procedure to etch the tips is used to yield reproducible sub-100-nm apex. We also study electron transport through single-molecule junctions formed by a single octanethiol molecule bonded by the thiol anchoring group to a gold electrode and linked to a carbon tip by the methyl group. We observe the presence of conductance plateaus during the stretching of the molecular bridge, which is the signature of the formation of a molecular junction.

  19. Carbon-fiber tips for scanning probe microscopes and molecular electronics experiments

    PubMed Central

    2012-01-01

    We fabricate and characterize carbon-fiber tips for their use in combined scanning tunneling and force microscopy based on piezoelectric quartz tuning fork force sensors. An electrochemical fabrication procedure to etch the tips is used to yield reproducible sub-100-nm apex. We also study electron transport through single-molecule junctions formed by a single octanethiol molecule bonded by the thiol anchoring group to a gold electrode and linked to a carbon tip by the methyl group. We observe the presence of conductance plateaus during the stretching of the molecular bridge, which is the signature of the formation of a molecular junction. PMID:22587692

  20. Intraoperative fracture of phacoemulsification tip.

    PubMed

    Angmo, Dewang; Khokhar, Sudarshan K; Ganguly, Anasua

    2014-01-01

    Phacoemulsification (phaco) is an established procedure for cataract extraction and has undergone a significant advances in techniques, machines and phaco tips. The Aspiration Bypass System (ABS) phaco tip was introduced for phacoemulsification in 1998. The ABS tip allows fluid to be drawn through the opening when the phaco tip is occluded by nuclear material. The ABS tip allowed the safe use of high vacuum and flow rates and improved chamber stability by decreasing surge and therefore reducing intraoperative complications. To date, no disadvantages of ABS tips have been reported. We report a unique case of an intraoperative break of an ABS phaco tip during routine cataract surgery.

  1. Intraoperative Fracture of Phacoemulsification Tip

    PubMed Central

    Angmo, Dewang; Khokhar, Sudarshan K.; Ganguly, Anasua

    2014-01-01

    Phacoemulsification (phaco) is an established procedure for cataract extraction and has undergone a significant advances in techniques, machines and phaco tips. The Aspiration Bypass System (ABS) phaco tip was introduced for phacoemulsification in 1998. The ABS tip allows fluid to be drawn through the opening when the phaco tip is occluded by nuclear material. The ABS tip allowed the safe use of high vacuum and flow rates and improved chamber stability by decreasing surge and therefore reducing intraoperative complications. To date, no disadvantages of ABS tips have been reported. We report a unique case of an intraoperative break of an ABS phaco tip during routine cataract surgery. PMID:24669153

  2. Molecular mechanisms of dendrite morphogenesis

    PubMed Central

    Arikkath, Jyothi

    2012-01-01

    Dendrites are key integrators of synaptic information in neurons and play vital roles in neuronal plasticity. Hence, it is necessary that dendrite arborization is precisely controlled and coordinated with synaptic activity to ensure appropriate functional neural network integrity. In the past several years, it has become increasingly clear that several cell intrinsic and extrinsic mechanisms contribute to dendritic arborization. In this review, we will discuss some of the molecular mechanisms that regulate dendrite morphogenesis, particularly in cortical and hippocampal pyramidal neurons and some of the implications of aberrant dendritic morphology for human disease. Finally, we will discuss the current challenges and future directions in the field. PMID:23293584

  3. Comparison of fixation properties between coil-type and screw-type anchors for rotator cuff repair: A virtual pullout testing using 3-dimensional finite element method.

    PubMed

    Sano, Hirotaka; Tokunaga, Masako; Noguchi, Moriyuki; Inawashiro, Takashi; Irie, Taichi; Abe, Hiroo; Abrassart, Sophie; Itoi, Eiji

    2016-07-01

    Pullout of inserted anchor constitutes one of the pathomechanisms of re-tearing after rotator cuff repair. The purpose of the present study was to investigate the fixation properties of suture anchors using 3-dimensional finite element method. The computer models of three types of anchors (TwinFix Ti, HEALICOIL PK and HEALICOIL RG) were inserted into the isotropic cube model that simulated cancellous bone. In the virtual pullout testing, a tensile load (500 N) along the long axis of the inserted anchor was applied to the site of suture thread attachment to simulate a traction force. The distribution of von Mises equivalent stress, the failure patterns of elements inside the cube and the anchor displacement were compared among the three anchors. In TwinFix Ti, the highest stress concentration was seen around the anchor threads close to the surface of the cube, which caused element failure at this site. On the other hand, both HEALICOIL PK and HEALICOIL RG demonstrated a high stress concentration as well as element failure around the anchor tip. Comparing the anchor displacement, HEALICOIL RG showed the smallest displacement among the three anchors. The tensile loads that required a 0.1-mm displacement for TwinFix Ti, HEALICOIL PK and HEALICOIL RG were 400 N, 370 N, and greater than 500 N, respectively. The bony structures close to the footprint surface may be damaged during surgery due to preparation for the bony bed as well as the insertion of anchors. Thus, we assumed that HEALICOIL RG represented the best initial fixation properties among the three anchors tested. Virtual pullout testing using 3-dimensional finite element method could reveal the detailed biomechanical characteristics of each suture anchor, which would be important for shoulder surgeons to improve the clinical outcomes of rotator cuff repair. Copyright © 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

  4. A lunar/Martian anchor emplacement system

    NASA Technical Reports Server (NTRS)

    Clinton, Dustin; Holt, Andrew; Jantz, Erik; Kaufman, Teresa; Martin, James; Weber, Reed

    1993-01-01

    On the Moon or Mars, it is necessary to have an anchor, or a stable, fixed point able to support the forces necessary to rescue a stuck vehicle, act as a stake for a tent in a Martian gale, act as a fulcrum in the erection of general construction poles, or support tent-like regolith shields. The anchor emplacement system must be highly autonomous. It must supply the energy and stability for anchor deployment. The goal of the anchor emplacement system project is to design and build a prototype anchor and to design a conceptual anchor emplacement system. Various anchors were tested in a 1.3 cubic meter test bed containing decomposed granite. A simulated lunar soil was created by adjusting the moisture and compaction characteristics of the soil. We conducted tests on emplacement torque, amount of force the anchor could withstand before failure, anchor pull out force at various angles, and soil disturbances caused by placing the anchor. A single helix auger anchor performed best in this test bed based on energy to emplace, and the ultimate holding capacity. The anchor was optimized for ultimate holding capacity, minimum emplacement torque, and minimum soil disturbance in sandy soils yielding the following dimensions: helix diameter (4.45 cm), pitch (1.27 cm), blade thickness (0.15 cm), total length (35.56 cm), shaft diameter (0.78 cm), and a weight of 212.62 g. The experimental results showed that smaller diameter, single-helix augers held more force than larger diameter augers for a given depth. The emplacement system consists of a flywheel and a motor for power, sealed in a protective box supported by four legs. The flywheel system was chosen over a gear system based on its increased reliability in the lunar environment.

  5. Ships at anchor, Gulf of Oman

    NASA Technical Reports Server (NTRS)

    1983-01-01

    These supertankers, riding at anchor off the coast of the United Arab Emirates, Gulf of Oman (25.5N, 56.5E) cast long shadows and eddy currents in the late afternoon sun. The ships are anchored just outside the Persian Gulf. Because of a surplus of supertankers in the world, many of them are simply moored in the Gulf of Oman where they can be safely anchored and yet be close to the oil ports when activated.

  6. Modification of dendritic development.

    PubMed

    Feria-Velasco, Alfredo; del Angel, Alma Rosa; Gonzalez-Burgos, Ignacio

    2002-01-01

    Since 1890 Ramón y Cajal strongly defended the theory that dendrites and their processes and spines had a function of not just nutrient transport to the cell body, but they had an important conductive role in neural impulse transmission. He extensively discussed and supported this theory in the Volume 1 of his extraordinary book Textura del Sistema Nervioso del Hombre y de los Vertebrados. Also, Don Santiago significantly contributed to a detailed description of the various neural components of the hippocampus and cerebral cortex during development. Extensive investigation has been done in the last Century related to the functional role of these complex brain regions, and their association with learning, memory and some limbic functions. Likewise, the organization and expression of neuropsychological qualities such as memory, exploratory behavior and spatial orientation, among others, depend on the integrity and adequate functional activity of the cerebral cortex and hippocampus. It is known that brain serotonin synthesis and release depend directly and proportionally on the availability of its precursor, tryptophan (TRY). By using a chronic TRY restriction model in rats, we studied their place learning ability in correlation with the dendritic spine density of pyramidal neurons in field CA1 of the hippocampus during postnatal development. We have also reported alterations in the maturation pattern of the ability for spontaneous alternation and task performance evaluating short-term memory, as well as adverse effects on the density of dendritic spines of hippocampal CA1 field pyramidal neurons and on the dendritic arborization and the number of dendritic spines of pyramidal neurons from the third layer of the prefrontal cortex using the same model of TRY restriction. The findings obtained in these studies employing a modified Golgi method, can be interpreted as a trans-synaptic plastic response due to understimulation of serotoninergic receptors located in the

  7. The role of the dendritic growth model dimensionality in predicting the Columnar to Equiaxed Transition (CET)

    NASA Astrophysics Data System (ADS)

    Seredyński, M.; Rebow, M.; Banaszek, J.

    2017-06-01

    The dendrite tip kinetics model accuracy relies on the reliability of the stability constant used, which is usually experimentally determined for 3D situations and applied to 2D models. The paper reports authors` attempts to cure the situation by deriving 2D dendritic tip scaling parameter for aluminium-based alloy: Al-4wt%Cu. The obtained parameter is then incorporated into the KGT dendritic growth model in order to compare it with the original 3D KGT counterpart and to derive two-dimensional and three-dimensional versions of the modified Hunt's analytical model for the columnar-to-equiaxed transition (CET). The conclusions drawn from the above analysis are further confirmed through numerical calculations of the two cases of Al-4wt%Cu metallic alloy solidification using the front tracking technique. Results, including the porous zone-under-cooled liquid front position, the calculated solutal under-cooling, the average temperature gradient at a front of the dendrite tip envelope and a new predictor of the relative tendency to form an equiaxed zone, are shown, compared and discussed for two numerical cases. The necessity to calculate sufficiently precise values of the tip scaling parameter in 2D and 3D is stressed.

  8. Anchored Instruction and Anchored Assessment: An Ecological Approach to Measuring Situated Learning.

    ERIC Educational Resources Information Center

    Young, Michael F.; Kulikowich, Jonna M.

    Anchored instruction and anchored assessment are described and illustrated through a mathematics problem from the Jasper problem solving series developed at Vanderbilt University in Nashville (Tennessee). Anchored instruction is instruction situated in a context complex enough to provide meaning and reasons for why information is useful. Problems…

  9. Magnet pole tips

    DOEpatents

    Thorn, Craig E.; Chasman, Chellis; Baltz, Anthony J.

    1984-04-24

    An improved magnet which more easily provides a radially increasing magnetic field, as well as reduced fringe field and requires less power for a given field intensity. The subject invention comprises a pair of spaced, opposed magnetic poles which further comprise a pair of pole roots, each having a pole tip attached to its center. The pole tips define the gap between the magnetic poles and at least a portion of each pole tip is separated from its associated pole root. The separation begins at a predetermined distance from the center of the pole root and increases with increasing radial distance while being constant with azimuth within that portion. Magnets in accordance with the subject invention have been found to be particularly advantageous for use in large isochronous cyclotrons.

  10. Magnet pole tips

    DOEpatents

    Thorn, C.E.; Chasman, C.; Baltz, A.J.

    1981-11-19

    An improved magnet more easily provides a radially increasing magnetic field, as well as reduced fringe field and requires less power for a given field intensity. The subject invention comprises a pair of spaced, opposed magnetic poles which further comprise a pair of pole roots, each having a pole tip attached to its center. The pole tips define the gap between the magnetic poles and at least a portion of each pole tip is separated from its associated pole root. The separation begins at a predetermined distance from the center of the pole root and increases with increasing radial distance while being constant with azimuth within that portion. Magnets in accordance with the subject invention have been found to be particularly advantageous for use in large isochronous cyclotrons.

  11. Evolving Indications for Tips.

    PubMed

    Smith, Mitchell; Durham, Janette

    2016-03-01

    Transjugular intrahepatic portosystemic shunt creation is a well-established therapy for refractory variceal bleeding and refractory ascites in patients who do not tolerate repeated large volume paracentesis. Experience and technical improvements including covered stents have led to improved TIPS outcomes that have encouraged an expanded application. Evidence for other less frequent indications continues to accumulate, including the indications of primary prophylaxis in patients with high-risk acute variceal bleeding, gastric and ectopic variceal bleeding, primary treatment of medically refractory ascites, recurrent refractory ascites following liver transplantation, hepatic hydrothorax, hepatorenal syndrome, Budd-Chiari syndrome, and portal vein thrombosis. Treatment of patients with high-risk acute variceal bleeding with early TIPS and using transjugular intrahepatic portosystemic shunts as a primary therapy rather than large volume paracentesis for refractory ascites would likely be the 2 circumstances that permit expansion in the frequency of TIPS procedures. The remaining populations discussed above are relatively rare.

  12. Free dendritic growth in viscous melts - Cyclohexanol

    NASA Technical Reports Server (NTRS)

    Singh, N. B.; Glicksman, M. E.

    1989-01-01

    Experiments were carried out to measure the growth speed, V, and dendritic tip radius, R, of highly purified cyclohexanol. The data show that VR-squared = constant over the entire experimentally observed supercooling range, Delta T is between 0.1 and 1 K. The stability parameter estimated from this result indicates that sigma(asterisk) = 0.027, a value in good agreement with the values of sigma(asterisk) found for the cubic plastic crystals succinonitrile pivalic acid. Cyclohexanol differs from other carefully measured plastic crystals in that the viscosity of its melt at the melting point is about 20 times higher, so gravity-induced convection remains weak even at small supercoolings.

  13. Free dendritic growth in viscous melts - Cyclohexanol

    NASA Technical Reports Server (NTRS)

    Singh, N. B.; Glicksman, M. E.

    1989-01-01

    Experiments were carried out to measure the growth speed, V, and dendritic tip radius, R, of highly purified cyclohexanol. The data show that VR-squared = constant over the entire experimentally observed supercooling range, Delta T is between 0.1 and 1 K. The stability parameter estimated from this result indicates that sigma(asterisk) = 0.027, a value in good agreement with the values of sigma(asterisk) found for the cubic plastic crystals succinonitrile pivalic acid. Cyclohexanol differs from other carefully measured plastic crystals in that the viscosity of its melt at the melting point is about 20 times higher, so gravity-induced convection remains weak even at small supercoolings.

  14. Characterization of Optical Lenses to be Considered for the Imaging of Crystal Dendrite Growth

    NASA Technical Reports Server (NTRS)

    Wing, Frank M.

    1999-01-01

    Dynamic fracture is a phenomenon that is extremely sensitive to small perturbations in system parameters. This phenomenon is, in some ways, similar to that of dendritic crystal growth, although it is governed by different physical principles. Crystal dendrite growth patterns are affected by parameters such as temperature, pressure, and gravity. By studying the behavior of crystal dendrites in a controlled, microgravity environment, a greater understanding of dynamic fracture could be revealed. A sealed cubical container contains four stingers, which facilitate the growth of crystal dendrites. The container has five windows and is emersed in a liquid, for thermal isolation. The tip of a dendrite can advance in any direction, therefore three-dimensional images of the process are desired. Furthermore, because of the rapid growth rate, a fast image frame rate is required for accurate tracking of dendrite tip velocity. In addition, optical parameters such as field of view, depth of focus, and resolution are examined, as well as the working distance between a lens and the target of observation.

  15. Characterization of Optical Lenses to be Considered for the Imaging of Crystal Dendrite Growth

    NASA Technical Reports Server (NTRS)

    Wing, Frank M.

    1999-01-01

    Dynamic fracture is a phenomenon that is extremely sensitive to small perturbations in system parameters. This phenomenon is, in some ways, similar to that of dendritic crystal growth, although it is governed by different physical principles. Crystal dendrite growth patterns are affected by parameters such as temperature, pressure, and gravity. By studying the behavior of crystal dendrites in a controlled, microgravity environment, a greater understanding of dynamic fracture could be revealed. A sealed cubical container contains four stingers, which facilitate the growth of crystal dendrites. The container has five windows and is emersed in a liquid, for thermal isolation. The tip of a dendrite can advance in any direction, therefore three-dimensional images of the process are desired. Furthermore, because of the rapid growth rate, a fast image frame rate is required for accurate tracking of dendrite tip velocity. In addition, optical parameters such as field of view, depth of focus, and resolution are examined, as well as the working distance between a lens and the target of observation.

  16. Dendritic Spikes in Sensory Perception.

    PubMed

    Manita, Satoshi; Miyakawa, Hiroyoshi; Kitamura, Kazuo; Murayama, Masanori

    2017-01-01

    What is the function of dendritic spikes? One might argue that they provide conditions for neuronal plasticity or that they are essential for neural computation. However, despite a long history of dendritic research, the physiological relevance of dendritic spikes in brain function remains unknown. This could stem from the fact that most studies on dendrites have been performed in vitro. Fortunately, the emergence of novel techniques such as improved two-photon microscopy, genetically encoded calcium indicators (GECIs), and optogenetic tools has provided the means for vital breakthroughs in in vivo dendritic research. These technologies enable the investigation of the functions of dendritic spikes in behaving animals, and thus, help uncover the causal relationship between dendritic spikes, and sensory information processing and synaptic plasticity. Understanding the roles of dendritic spikes in brain function would provide mechanistic insight into the relationship between the brain and the mind. In this review article, we summarize the results of studies on dendritic spikes from a historical perspective and discuss the recent advances in our understanding of the role of dendritic spikes in sensory perception.

  17. Dendritic Spikes in Sensory Perception

    PubMed Central

    Manita, Satoshi; Miyakawa, Hiroyoshi; Kitamura, Kazuo; Murayama, Masanori

    2017-01-01

    What is the function of dendritic spikes? One might argue that they provide conditions for neuronal plasticity or that they are essential for neural computation. However, despite a long history of dendritic research, the physiological relevance of dendritic spikes in brain function remains unknown. This could stem from the fact that most studies on dendrites have been performed in vitro. Fortunately, the emergence of novel techniques such as improved two-photon microscopy, genetically encoded calcium indicators (GECIs), and optogenetic tools has provided the means for vital breakthroughs in in vivo dendritic research. These technologies enable the investigation of the functions of dendritic spikes in behaving animals, and thus, help uncover the causal relationship between dendritic spikes, and sensory information processing and synaptic plasticity. Understanding the roles of dendritic spikes in brain function would provide mechanistic insight into the relationship between the brain and the mind. In this review article, we summarize the results of studies on dendritic spikes from a historical perspective and discuss the recent advances in our understanding of the role of dendritic spikes in sensory perception. PMID:28261060

  18. Observed Score Equating Using a Mini-Version Anchor and an Anchor with Less Spread of Difficulty: A Comparison Study

    ERIC Educational Resources Information Center

    Liu, Jinghua; Sinharay, Sandip; Holland, Paul; Feigenbaum, Miriam; Curley, Edward

    2011-01-01

    Two different types of anchors are investigated in this study: a mini-version anchor and an anchor that has a less spread of difficulty than the tests to be equated. The latter is referred to as a midi anchor. The impact of these two different types of anchors on observed score equating are evaluated and compared with respect to systematic error…

  19. 21 CFR 872.3130 - Preformed anchor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Preformed anchor. 872.3130 Section 872.3130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3130 Preformed anchor. (a) Identification. A...

  20. 21 CFR 872.3130 - Preformed anchor.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Preformed anchor. 872.3130 Section 872.3130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3130 Preformed anchor. (a) Identification. A...

  1. 21 CFR 872.3130 - Preformed anchor.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Preformed anchor. 872.3130 Section 872.3130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3130 Preformed anchor. (a) Identification. A...

  2. 21 CFR 872.3130 - Preformed anchor.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Preformed anchor. 872.3130 Section 872.3130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3130 Preformed anchor. (a) Identification. A...

  3. 21 CFR 872.3130 - Preformed anchor.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Preformed anchor. 872.3130 Section 872.3130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3130 Preformed anchor. (a) Identification. A...

  4. DSSC anchoring groups: a surface dependent decision.

    PubMed

    O'Rourke, C; Bowler, D R

    2014-05-14

    Electrodes in dye sensitised solar cells are typically nanocrystalline anatase TiO2 with a majority (1 0 1) surface exposed. Generally the sensitising dye employs a carboxylic anchoring moiety through which it adheres to the TiO₂ surface. Recent interest in exploiting the properties of differing TiO₂ electrode morphologies, such as rutile nanorods exposing the (1 1 0) surface and anatase electrodes with high percentages of the (0 0 1) surface exposed, begs the question of whether this anchoring strategy is best, irrespective of the majority surface exposed. Here we address this question by presenting density functional theory calculations contrasting the binding properties of two promising anchoring groups, phosphonic acid and boronic acid, to that of carboxylic acid. Anchor-electrode interactions are studied for the prototypical anatase (1 0 1) surface, along with the anatase (0 0 1) and rutile (1 1 0) surfaces. Finally the effect of using these alternative anchoring groups to bind a typical coumarin dye (NKX-2311) to these TiO₂ substrates is examined. Significant differences in the binding properties are found depending on both the anchor and surface, illustrating that the choice of anchor is necessarily dependent upon the surface exposed in the electrode. In particular the boronic acid is found to show the potential to be an excellent anchor choice for electrodes exposing the anatase (0 0 1) surface.

  5. Method of fabrication of anchored nanostructure materials

    DOEpatents

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2013-11-26

    Methods for fabricating anchored nanostructure materials are described. The methods include heating a nano-catalyst under a protective atmosphere to a temperature ranging from about 450.degree. C. to about 1500.degree. C. and contacting the heated nano-catalysts with an organic vapor to affix carbon nanostructures to the nano-catalysts and form the anchored nanostructure material.

  6. Anchoring and Publicity Effects in Clinical Judgment.

    ERIC Educational Resources Information Center

    Friedlander, Myrna L.; Stockman, Susan J.

    1983-01-01

    Tested anchoring and publicity effects in clinicians' (N=46) successive judgments of detailed interview notes. Results indicated significant anchoring in one case suggesting a clinical bias. Public justification was related neither to subjects' ratings, to reported confidence in their ratings, nor differentially by case. (JAC)

  7. Anchors of Religious Commitment in Adolescents

    ERIC Educational Resources Information Center

    Layton, Emily; Dollahite, David C.; Hardy, Sam A.

    2011-01-01

    This study explores adolescent religious commitment using qualitative data from a religiously diverse (Jewish, Christian, Muslim) sample of 80 adolescents. A new construct, "anchors of religious commitment," grounded in interview data, is proposed to describe what adolescents commit to as a part of their religious identity. Seven anchors of…

  8. 33 CFR 401.15 - Stern anchors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Stern anchors. 401.15 Section 401.15 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Condition of Vessels § 401.15 Stern anchors. (a) Every...

  9. Crossed ring anchored disk resonator for self-alignment of the anchor

    PubMed Central

    Baghelani, Masoud; Ghavifekr, Habib Badri; Ebrahimi, Afshin

    2013-01-01

    Misalignment is a problematic challenge in RF MEMS resonators. It causes asymmetry in the ultra symmetric radial contour mode disk resonators and degrades their performance by increasing the insertion loss and decreasing their quality factors (Q). Self-alignment method seems to be a good solution for misalignment problem, but it cannot be directly applied on high performance ring shape anchored resonators. This paper discusses misalignment effects for the ring shape anchored resonators and proposes a method for reconfiguring its anchor to be compatible with self-alignment process. Simulation results validate that the crossed ring anchor structure has the same resonance characteristics with the complete ring shape anchored resonator. PMID:25685477

  10. Magnetic and dendritic catalysts.

    PubMed

    Wang, Dong; Deraedt, Christophe; Ruiz, Jaime; Astruc, Didier

    2015-07-21

    The recovery and reuse of catalysts is a major challenge in the development of sustainable chemical processes. Two methods at the frontier between homogeneous and heterogeneous catalysis have recently emerged for addressing this problem: loading the catalyst onto a dendrimer or onto a magnetic nanoparticle. In this Account, we describe representative examples of these two methods, primarily from our research group, and compare them. We then describe new chemistry that combines the benefits of these two methods of catalysis. Classic dendritic catalysis has involved either attaching the catalyst covalently at the branch termini or within the dendrimer core. We have used chelating pyridyltriazole ligands to insolubilize catalysts at the termini of dendrimers, providing an efficient, recyclable heterogeneous catalysts. With the addition of dendritic unimolecular micelles olefin metathesis reactions catalyzed by commercial Grubbs-type ruthenium-benzylidene complexes in water required unusually low amounts of catalyst. When such dendritic micelles include intradendritic ligands, both the micellar effect and ligand acceleration promote faster catalysis in water. With these types of catalysts, we could carry out azide alkyne cycloaddition ("click") chemistry with only ppm amounts of CuSO4·5H2O and sodium ascorbate under ambient conditions. Alternatively we can attach catalysts to the surface of superparamagnetic iron oxide nanoparticles (SPIONs), essentially magnetite (Fe3O4) or maghemite (γ-Fe2O3), offering the opportunity to recover the catalysts using magnets. Taking advantage of the merits of both of these strategies, we and others have developed a new generation of recyclable catalysts: dendritic magnetically recoverable catalysts. In particular, some of our catalysts with a γ-Fe2O3@SiO2 core and 1,2,3-triazole tethers and loaded with Pd nanoparticles generate strong positive dendritic effects with respect to ligand loading, catalyst loading, catalytic activity and

  11. Silicon dendritic web material

    NASA Technical Reports Server (NTRS)

    Meier, D. L.; Campbell, R. B.; Sienkiewicz, L. J.; Rai-Choudhury, P.

    1982-01-01

    The development of a low cost and reliable contact system for solar cells and the fabrication of several solar cell modules using ultrasonic bonding for the interconnection of cells and ethylene vinyl acetate as the potting material for module encapsulation are examined. The cells in the modules were made from dendritic web silicon. To reduce cost, the electroplated layer of silver was replaced with an electroplated layer of copper. The modules that were fabricated used the evaporated Ti, Pd, Ag and electroplated Cu (TiPdAg/Cu) system. Adherence of Ni to Si is improved if a nickel silicide can be formed by heat treatment. The effectiveness of Ni as a diffusion barrier to Cu and the ease with which nickel silicide is formed is discussed. The fabrication of three modules using dendritic web silicon and employing ultrasonic bonding for interconnecting calls and ethylene vinyl acetate as the potting material is examined.

  12. Newsletter Design Tips.

    ERIC Educational Resources Information Center

    Welch, Sally

    This paper presents detailed tips on newsletter design. Following an overview, it discusses effective design, anatomy of a page, type, designing tools (organizational tools, text organizers, emphasizing tools, and graphics, presented with some do's and don'ts), and a list of other items to consider. Three appendixes contain a brief glossary of…

  13. Tips for Energy Savers.

    ERIC Educational Resources Information Center

    Department of Energy, Washington, DC.

    According to 1986 U.S. Department of Energy data, 48% of our residential energy is used to heat and cool our homes, 16% goes for heating water, 12% is used to refrigerators and freezers, and the remaining 24% goes into lighting, cooking, and running appliances. This booklet contains tips for saving energy, including sections on: (1) draft-proof…

  14. Taxicab tipping and sunlight

    PubMed Central

    2017-01-01

    Does the level of sunlight affect the tipping percentage in taxicab rides in New York City? We examined this question using data on 13.82 million cab rides from January to October in 2009 in New York City combined with data on hourly levels of solar radiation. We found a small but statistically significant positive relationship between sunlight and tipping, with an estimated tipping increase of 0.5 to 0.7 percentage points when transitioning from a dark sky to full sunshine. The findings are robust to two-way clustering of standard errors based on hour-of-the-day and day-of-the-year and controlling for day-of-the-year, month-of-the-year, cab driver fixed effects, weather conditions, and ride characteristics. The NYC cab ride context is suitable for testing the association between sunlight and tipping due to the largely random assignment of riders to drivers, direct exposure to sunlight, and low confounding from variation in service experiences. PMID:28594917

  15. Nantucket Pine Tip Moth

    Treesearch

    Harry O. III Yates; Nell A. Overgaard; Thomas W. Koerber

    1981-01-01

    The Nantucket pine tip moth, Rhyacionia frustrana (Comstock),4 is a major forest insect pest in the United States. Its range extends from Massachusetts to Florida and west to Texas. It was found in San Diego County, California, in 1971 and traced to infested pine seedlings shipped from Georgia in 1967. The moth has since spread north and east in California and is now...

  16. EcoTipping Points

    ERIC Educational Resources Information Center

    Marten, Gerald G.; Matthews, Catherine E.

    2009-01-01

    Contrary to what we often hear and teach, there is good news to be found on the environmental front. Environmental success stories show us not only that sustainability is possible, but also how people have made it happen. We can make these stories and their lessons accessible to students with help from the EcoTipping Points Project, which has…

  17. Tips from the Classroom.

    ERIC Educational Resources Information Center

    Benedetti, Teresa; De Gaetano, Yvonne; Weinstein-McShane, Ruth; Paez, Doris; McCarty, Laurie; Ehlers-Zavala, Fabiola; Bakken, Jeffrey P.

    1997-01-01

    This group of classroom tips discusses the benefits of peer coaching, peer group conversation about teachers' classroom experiences, using visual displays for collegial sharing, using cultural brokers in educational settings, and the role of picture books in developing literacy skills in diverse students with disabilities. (Author/CK)

  18. Taxicab tipping and sunlight.

    PubMed

    Devaraj, Srikant; Patel, Pankaj C

    2017-01-01

    Does the level of sunlight affect the tipping percentage in taxicab rides in New York City? We examined this question using data on 13.82 million cab rides from January to October in 2009 in New York City combined with data on hourly levels of solar radiation. We found a small but statistically significant positive relationship between sunlight and tipping, with an estimated tipping increase of 0.5 to 0.7 percentage points when transitioning from a dark sky to full sunshine. The findings are robust to two-way clustering of standard errors based on hour-of-the-day and day-of-the-year and controlling for day-of-the-year, month-of-the-year, cab driver fixed effects, weather conditions, and ride characteristics. The NYC cab ride context is suitable for testing the association between sunlight and tipping due to the largely random assignment of riders to drivers, direct exposure to sunlight, and low confounding from variation in service experiences.

  19. Guyline anchor design keys rig stability

    SciTech Connect

    Murphy, R.J.; Laguros, J.G.

    1983-09-01

    Inadequate design and field installation of ground anchors at lease well sites have frequently led to the collapse of well service rigs operating in high surface wind conditions (>50 mph). Such catastrophes incur significant equipment damage and injury to operating personnel. Although collapse of a well service rig can be attributed to inadequate strength in the guyline connection to the mast or anchor or to deformed or inadequate wire rope strength in the guyline itself, most failures result from improperly placed anchors not meeting API specifications to withstand 14,000 lb of force in tension. This article defines the length, diameter, and depth necessary (based on soil conditions) for a buried guyline anchor to meet API specifications. Deficiencies in guyline connection and strength can be alleviated by following the manufacturer's guidance on size of wire rope, its inspection, and size connection criteria in mounting guyline connectors to the mast and anchor.

  20. Dendritic Materials Systems

    DTIC Science & Technology

    2003-09-22

    2-hydroxyethyl)-e-caprolactone,” Macromolecules, 32, 6881-4, (1999). Yu, D.; Vladimirov, N.; Fréchet, J.M.J. “ MALDI - TOF in the Characterization of...Mat Sci. Eng., (1999). Yu, D.; Vladimirov, N.; Fréchet, J. M. J. “ MALDI - TOF Mass Spectrometry in the Characterization of Dendritic-Linear Block and...with long endgroups capable of chain entanglements providing uniform continuous films. We found that the surface properties of polyetherimide ( PEI

  1. Human dendritic cell subsets

    PubMed Central

    Collin, Matthew; McGovern, Naomi; Haniffa, Muzlifah

    2013-01-01

    Summary Dendritic cells are highly adapted to their role of presenting antigen and directing immune responses. Developmental studies indicate that DCs originate independently from monocytes and tissue macrophages. Emerging evidence also suggests that distinct subsets of DCs have intrinsic differences that lead to functional specialisation in the generation of immunity. Comparative studies are now allowing many of these properties to be more fully understood in the context of human immunology. PMID:23621371

  2. Silicon dendritic web growth

    NASA Technical Reports Server (NTRS)

    Duncan, S.

    1984-01-01

    Technological goals for a silicon dendritic web growth program effort are presented. Principle objectives for this program include: (1) grow long web crystals front continuously replenished melt; (2) develop temperature distribution in web and melt; (3) improve reproductibility of growth; (4) develop configurations for increased growth rates (width and speed); (5) develop new growth system components as required for improved growth; and (6) evaluate quality of web growth.

  3. The effect of accuracy motivation on anchoring and adjustment: do people adjust from provided anchors?

    PubMed

    Simmons, Joseph P; LeBoeuf, Robyn A; Nelson, Leif D

    2010-12-01

    Increasing accuracy motivation (e.g., by providing monetary incentives for accuracy) often fails to increase adjustment away from provided anchors, a result that has led researchers to conclude that people do not effortfully adjust away from such anchors. We challenge this conclusion. First, we show that people are typically uncertain about which way to adjust from provided anchors and that this uncertainty often causes people to believe that they have initially adjusted too far away from such anchors (Studies 1a and 1b). Then, we show that although accuracy motivation fails to increase the gap between anchors and final estimates when people are uncertain about the direction of adjustment, accuracy motivation does increase anchor-estimate gaps when people are certain about the direction of adjustment, and that this is true regardless of whether the anchors are provided or self-generated (Studies 2, 3a, 3b, and 5). These results suggest that people do effortfully adjust away from provided anchors but that uncertainty about the direction of adjustment makes that adjustment harder to detect than previously assumed. This conclusion has important theoretical implications, suggesting that currently emphasized distinctions between anchor types (self-generated vs. provided) are not fundamental and that ostensibly competing theories of anchoring (selective accessibility and anchoring-and-adjustment) are complementary.

  4. TIPS geometry influences patency.

    PubMed

    Klasen-Sansone, J; Bode, J; Lanzman, R S; Kubitz, R; Immig, S; Heusch, P; Antoch, G; Häussinger, D; Blondin, D

    2015-01-01

    The purpose of this study was to evaluate potential causes of Transjugular intrahepatic portosystemic shunt (TIPS) dysfunction. We retrospectively evaluated 26 patients who required TIPS revision (group I) and 24 patients who did not require any further intervention (group II) within the first two years following TIPS implantation. The distance of the distal end of the stent to the hepatocaval junction was measured. Furthermore, the angle between the stent and the portal vein (inflow) and the angle between the stent and the hepatic vein (outflow) were measured. Furthermore, the following data were evaluated: pre- and postinterventional portal pressure gradients, maximal postinterventional flow and blood values [C-reactive protein (CRP), bilirubin, glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT)]. Compared with control subjects, patients who required TIPS revision showed a significantly longer distance from the distal end of the stent to the hepatocaval junction (I: 17.3 ± 10 mm, II: 6.7 ± 5.7 mm, p < 0.001). There was a statistically significant correlation between the above named distance and the time to revision (Pearson's correlation coefficient, r = 0.5, p = 0.01). In addition, patients with TIPS revision had a significantly larger angle of portalvenous inflow (alpha angle) than the control group (I: 100.5 ± 31.5°, II: 64.5 ± 31.6°, p < 0.001). Our results show that the distance from the end of the stent to the hepatocaval junction and the angle of portalvenous inflow are technical factors that may influence the shunt's patency rate. Of these two, the distance to the hepatocaval junction can be influenced easily by the interventionalist. © Georg Thieme Verlag KG Stuttgart · New York.

  5. Web-dendritic ribbon growth

    NASA Technical Reports Server (NTRS)

    Hilborn, R. B., Jr.; Faust, J. W., Jr.

    1976-01-01

    A web furnace was constructed for pulling dendritic-web samples. The effect of changes in the furnace thermal geometry on the growth of dendritic-web was studied. Several attempts were made to grow primitive dendrites for use as the dendritic seed crystals for web growth and to determine the optimum twin spacing in the dendritic seed crystal for web growth. Mathematical models and computer programs were used to determine the thermal geometries in the susceptor, crucible melt, meniscus, and web. Several geometries were determined for particular furnace geometries and growth conditions. The information obtained was used in conjunction with results from the experimental growth investigations in order to achieve proper conditions for sustained pulling of two dendrite web ribbons. In addition, the facilities for obtaining the following data were constructed: twin spacing, dislocation density, web geometry, resistivity, majority charge carrier type, and minority carrier lifetime.

  6. 14. TIP TOP MINE. TAILINGS LOCATED DIRECTLY WEST FROM TIP ...

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

    14. TIP TOP MINE. TAILINGS LOCATED DIRECTLY WEST FROM TIP TOP HOUSE. ID-31-C-12 WOODEN STRUCTURE IS VISIBLE IN TOP LEFT. CABLES VISIBLE LEFT AND CENTER OF TAILINGS. HOUSE IS JUST OVER APEX OF TAILINGS. CAMERA POINTED EAST. - Florida Mountain Mining Sites, Tip Top Mine, West face Florida Mountain, approximately 150 feet below summit, Silver City, Owyhee County, ID

  7. Tipping off endothelial tubes: nitric oxide drives tip cells.

    PubMed

    Priya, Mani Krishna; Sahu, Giriraj; Soto-Pantoja, David R; Goldy, Naga; Sundaresan, Abaya Meenakshi; Jadhav, Vivek; Barathkumar, T R; Saran, Uttara; Jaffar Ali, B M; Roberts, David D; Bera, Amal Kanti; Chatterjee, Suvro

    2015-04-01

    Angiogenesis, the formation of new blood vessels from pre-existing vessels, is a complex process that warrants cell migration, proliferation, tip cell formation, ring formation, and finally tube formation. Angiogenesis is initiated by a single leader endothelial cell called "tip cell," followed by vessel elongation by "stalk cells." Tip cells are characterized by their long filopodial extensions and expression of vascular endothelial growth factor receptor-2 and endocan. Although nitric oxide (NO) is an important modulator of angiogenesis, its role in angiogenic sprouting and specifically in tip cell formation is poorly understood. The present study tested the role of endothelial nitric oxide synthase (eNOS)/NO/cyclic GMP (cGMP) signaling in tip cell formation. In primary endothelial cell culture, about 40% of the tip cells showed characteristic sub-cellular localization of eNOS toward the anterior progressive end of the tip cells, and eNOS became phosphorylated at serine 1177. Loss of eNOS suppressed tip cell formation. Live cell NO imaging demonstrated approximately 35% more NO in tip cells compared with stalk cells. Tip cells showed increased level of cGMP relative to stalk cells. Further, the dissection of NO downstream signaling using pharmacological inhibitors and inducers indicates that NO uses the sGC/cGMP pathway in tip cells to lead angiogenesis. Taken together, the present study confirms that eNOS/NO/cGMP signaling defines the direction of tip cell migration and thereby initiates new blood vessel formation.

  8. Ultra-fast in-situ X-ray studies of evolving columnar dendrites in solidifying steel weld pools

    NASA Astrophysics Data System (ADS)

    Mirihanage, W. U.; Di Michiel, M.; Mathiesen, R. H.

    2015-06-01

    High-brilliance polychromatic synchrotron radiation has been used to conduct in-situ studies of the solidification microstructure evolution during simulated welding. The welding simulations were realized by rapidly fusing ∼ 5 mm spot in Fe-Cr-Ni steel. During the solid- liquid-solid phase transformations, a section of the weld pool was placed in an incident 50-150 keV polychromatic synchrotron X-ray beam, in a near-horizontal position at a very low inclination angle. Multiple high-resolution 2D detectors with very high frame rates were utilized to capture time resolved X-ray diffraction data from suitably oriented solid dendrites evolving in the weld pool. Comprehensive analysis of the diffraction data revealed individual and overall dendritic growth characteristics and relevant melt and solid flow dynamics during weld pool solidification, which was completed within 1.5 s. Columnar dendrite tip velocities were estimated from the experimental data and during early stages of solidification were exceeded 4 mm/s. The most remarkable observation revealed through the time-resolved reciprocal space observations are correlated to significant tilting of columnar type dendrites at their root during solidification, presumably caused by convective currents in the weld pool. When the columnar dendrite tilting are transformed to respective metric linear tilting velocities at the dendrite tip; tilting velocities are found to be in the same order of magnitude as the columnar tip growth velocities, suggesting a highly transient nature of growth conditions.

  9. IDGE: Isothermal Dendritic Growth Experiment

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The Isothermal Dendritic Growth Experiment (IDGE) flew on STS-62 to study the microscopic, tree-like structures (dendrites) that form within metals as they solidify from molten materials. The size, shape, and orientation of these dendrites affect the strength and usefulness of metals. Data from this experiment will be used to test and improve the mathematical models that support the industrial production of metals.

  10. Compact seaweed growth of peritectic phase on confined, flat properitectic dendrites

    NASA Astrophysics Data System (ADS)

    Ludwig, A.; Mogeritsch, J.

    2016-12-01

    Peritectic alloys form a variety of different solidification morphologies at low growth rates. An alloy with a concentration that corresponds to the hyper-peritectic limit should show a cellular/dendritic solidification of the peritectic phase for growth velocities above the corresponding constitutional undercooling limit. However, due to nucleation retardation of the peritectic phase we observed growth of properitectic dendrites before cellular growth of the peritectic could established. The transition happened via an overgrowth of dendrites with a thin layer of peritectic phase. The observations were made using a transparent, metal-like solidifying peritectic system that was solidified directionally in thin samples. In the gap between the flat dendrites and the tubing walls, the peritectic phase grew with a compact seaweed morphology, whereas in the interdendritic spacing it formed small-curved bumps. At same distance behind the tip region, more and more polycrystalline-like objects appeared at the elongated traces of the compact seaweed morphology.

  11. Effect of convective flow on stable dendritic growth in rapid solidification of a binary alloy

    NASA Astrophysics Data System (ADS)

    Galenko, P. K.; Danilov, D. A.; Reuther, K.; Alexandrov, D. V.; Rettenmayr, M.; Herlach, D. M.

    2017-01-01

    A model for anisotropic growth of a dendritic crystal in a binary mixture under non-isothermal conditions is presented. A criterion for a stable growth mode is given for the dendrite tip as a function of the thermal Péclet number and the ratio between the velocities of dendrite growth and solute diffusion in the liquid bulk. Limiting cases of known criteria for anisotropic dendrite growth at low and high growth Péclet numbers are provided. The inclusion of forced convective flow extends the range of theoretical predictions, especially to low growth velocities, thus eliminating systematic discrepancies between earlier models and observed experimental data, as shown by a comparison of model predictions with measured growth velocities in Ti-55 at% Al alloys solidified under electromagnetic levitation.

  12. Tips to Prevent Mosquito Bites

    MedlinePlus

    ... Mosquito Control Contact Us Share Tips to Prevent Mosquito Bites Información relacionada disponible en español Using the ... Also see Tips to Prevent Tick Bites. Remove Mosquito Habitats Eliminate standing water in rain gutters, old ...

  13. Safety Tips: Baseball (For Parents)

    MedlinePlus

    ... by U.S.A. Little League and the American Sports Medicine Institute: 7-8 years old: 50 pitches a ... ON THIS TOPIC Signing Kids Up for Sports Sports Medicine Center Safety Tips: Hockey Safety Tips: Basketball Competitive ...

  14. Propeller tip vortex interactions

    NASA Technical Reports Server (NTRS)

    Johnston, Robert T.; Sullivan, John P.

    1990-01-01

    Propeller wakes interacting with aircraft aerodynamic surfaces are a source of noise and vibration. For this reason, flow visualization work on the motion of the helical tip vortex over a wing and through the second stage of a counterrotation propeller (CRP) has been pursued. Initially, work was done on the motion of a propeller helix as it passes over the center of a 9.0 aspect ratio wing. The propeller tip vortex experiences significant spanwise displacements when passing across a lifting wing. A stationary propeller blade or stator was installed behind the rotating propeller to model the blade vortex interaction in a CRP. The resulting vortex interaction was found to depend on the relative vortex strengths and vortex sign.

  15. In-Situ Fracture Observation and Fracture Toughness Analysis of Zr-Based Amorphous Alloys Containing Ductile Dendrites

    NASA Astrophysics Data System (ADS)

    Jeon, Changwoo; Kim, Choongnyun Paul; Lee, Sunghak

    2012-10-01

    Effects of dendrite size on fracture properties of Zr-based amorphous alloys containing ductile β dendrites were explained by directly observing microfracture processes using an in-situ loading stage installed inside a scanning electron microscope (SEM) chamber. Three amorphous alloy plates having different thicknesses were fabricated by varying cooling rates after vacuum arc melting. The effective size of β dendrites was varied from 14.7 to 30.1 μm in the alloy plates, while their volume fraction was almost constant. According to microfracture observation of the alloy containing fine β dendrites, shear bands initiated at the amorphous matrix were connected with the notch tip as they were deepened through dendrites, which led to abrupt crack propagation. In the alloy containing coarser β dendrites, shear bands were initiated at the amorphous matrix to form a crack near the notch tip region and were expanded over large matrix areas. The crack propagation was frequently blocked by β dendrites, and many shear bands are formed near or in front of the propagating crack, thereby resulting in stable crack growth, which could be confirmed by the fracture resistance curve ( R-curve) behavior. This increase in fracture resistance with increasing crack length could be explained by mechanisms of blocking of crack growth, multiple shear band formation, and crack blunting.

  16. Anchored nanostructure materials and method of fabrication

    DOEpatents

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2012-11-27

    Anchored nanostructure materials and methods for their fabrication are described. The anchored nanostructure materials may utilize nano-catalysts that include powder-based or solid-based support materials. The support material may comprise metal, such as NiAl, ceramic, a cermet, or silicon or other metalloid. Typically, nanoparticles are disposed adjacent a surface of the support material. Nanostructures may be formed as anchored to nanoparticles that are adjacent the surface of the support material by heating the nano-catalysts and then exposing the nano-catalysts to an organic vapor. The nanostructures are typically single wall or multi-wall carbon nanotubes.

  17. Sutures and suture anchors: update 2003.

    PubMed

    Barber, F Alan; Herbert, Morley A; Richards, David P

    2003-11-01

    The purpose of this study was to evaluate recently introduced sutures and suture anchors for single-pull load-to-failure strength and failure mode. Experimental laboratory biomechanical study. Using an established protocol in fresh porcine femurs, anchors were tested in diaphyseal cortex, metaphyseal cortex, and cancellous troughs after threading them with either steel sutures or strong synthetic material to reduce the likelihood of suture breakage as a mode of failure. An Instron machine (Instron, Canton, MA) applied tensile loads parallel to the axis of insertion at a rate of 12.5 mm/second until failure, and mean anchor failure strengths were calculated. Mode of failure was recorded (anchor pullout, suture eyelet cutout, or wire breakage). Anchors tested included the RotorloC (Smith & Nephew Endoscopy, Andover, MA), TwinFix Ti 3.5, TwinFix Ti 5.0, and TwinFix AB (Smith & Nephew Endoscopy), Super Revo and UltraSorb (Linvatec, Largo, FL), Duet (Bionx Implants, Blue Bell, PA), AlloAnchor RC (Regeneration Technologies, Alachua, FL), Opus Magnum anchor (Opus Medical, San Juan Capistrano, CA), and the BioCorkscrew 5.0 and BioCorkscrew 6.5 (Arthrex, Naples, FL). Sutures tested were No.2 and No. 5 Ethibond (Ethicon, Somerville, NJ), No. 2 Panacryl (Mitek, a division of Ethicon, Somerville, NJ), and Nos. 2, 5, and 2-0 Fiberwire (Arthrex, Naples, FL). The sutures all broke in the midpoint of their tested strand away from the grips. The No. 2 Ethibond failed at a mean of 21 lb (92 N); No. 5 Ethibond failed at a mean of 44 lb (193 N); No. 2, No. 5, and No. 2-0 Fiberwire at means of 44 lb (188 N), 112 lb (483N), and 19 lb (82 N), respectively; and No. 2 Panacryl at a mean of 22 lb (99 N). The suture anchors all failed at levels higher than the associated sutures. Screw anchors showed higher load to failure values than nonscrew designs, and the new biodegradable anchors showed failure loads lower than the anchors. All anchors were stronger than the suture for which they are

  18. Numerical modeling of solidification morphologies and segregation patterns in cast dendritic alloys

    SciTech Connect

    Nastac, L.

    1999-11-26

    A comprehensive stochastic model for simulating the evolution of dendritic crystals during the solidification of binary alloys was developed. The model includes time-dependent calculations for temperature distribution, solute redistribution in the liquid and solid phases, curvature, and growth anisotropy without further assumptions on the nucleation and growth of dendritic crystals. Stochastic procedures previously developed by Nastac and Stefanescu for simulating dendritic grains were used to control the nucleation and growth of dendrites. A numerical algorithm based on an Eulerian-Lagrangian approach was developed to explicitly track the sharp solid/liquid (S/L) interface on a fixed Cartesian grid. Two-dimensional mesoscopic calculations (i.e., at the dendrite tip length scale) were performed to simulate the evolution of columnar and equiaxed dendritic morphologies including the formation of the columnar-to-equiaxed transition. The effects of solutal and curvature undercoolings on the evolution of both the dendrite morphology and segregation patterns during the solidification of binary alloys were analyzed in detail.

  19. Anchoring Revisited: The Role of the Comparative Question

    PubMed Central

    Grau, Ina; Bohner, Gerd

    2014-01-01

    When people estimate a numeric value after judging whether it is larger or smaller than a high or low anchor value (comparative question), estimates are biased in the direction of the anchor. One explanation for this anchoring effect is that people selectively access knowledge consistent with the anchor value as part of a positive test strategy. Two studies (total N = 184) supported the alternative explanation that people access knowledge consistent with their own answer to the comparative question. Specifically, anchoring effects emerged when the answer to the comparative question was unexpected (lower than the low anchor or higher than the high anchor). For expected answers (lower than the high anchor or higher than the low anchor), however, anchoring effects were attenuated or reversed. The anchor value itself was almost never reported as an absolute estimate. PMID:24454953

  20. Developing dendrites demonstrate unexpected specificity.

    PubMed

    Chalupa, Leo M

    2006-11-22

    Our knowledge of how developing dendrites attain their mature state is still rudimentary. In this issue of Neuron, Mumm et al. rely on time-lapsed analysis of ingrowing dendrites of retinal ganglion cells in transgenic zebrafish to show that this process is much more specific than has been suspected.

  1. Robust Molecular Anchoring to Graphene Electrodes.

    PubMed

    Sadeghi, Hatef; Sangtarash, Sara; Lambert, Colin

    2017-08-09

    Recent advances in the engineering of picoscale gaps between electroburnt graphene electrodes provide new opportunities for studying electron transport through electrostatically gated single molecules. But first we need to understand and develop strategies for anchoring single molecules to such electrodes. Here, for the first time we present a systematic theoretical study of transport properties using four different modes of anchoring zinc-porphyrin monomer, dimer, and trimer molecular wires to graphene electrodes. These involve either amine anchor groups, covalent C-C bonds to the edges of the graphene, or coupling via π-π stacking of planar polyaromatic hydrocarbons formed from pyrene or tetrabenzofluorene (TBF). π-π stacked pyrene anchors are particularly stable, which may be advantageous for forming robust single-molecule transistors. Despite their planar, multiatom coupling to the electrodes, pyrene anchors can exhibit both destructive interference and different degrees of constructive interference, depending on their connectivity to the porphyrin wire, which makes them attractive also for thermoelectricity. TBF anchors are more weakly coupled to both the graphene and the porphyrin wires and induce negative differential conductance at finite source-drain voltages. Furthermore, although direct C-C covalent bonding to the edges of graphene electrodes yields the highest electrical conductance, electron transport is significantly affected by the shape and size of the graphene electrodes because the local density of states at the carbon atoms connecting the electrode edges to the molecule is sensitive to the electrode surface shape. This sensitivity suggests that direct C-C bonding may be the most desirable for sensing applications. The ordering of the low-bias electrical conductances with different anchors is as follows: direct C-C coupling > π-π stacking with the pyrene anchors > direct coupling via amine anchors > π-π stacking with TBF anchors. Despite

  2. Anchor-Less Secure Session Mobility

    NASA Astrophysics Data System (ADS)

    Zugenmaier, Alf; Laganier, Julien; Prasad, Anand; Slavov, Kristian

    Communication session mobility relates transferring one endpoint of a communication session including its state from one device to another. Current proposals to deal with this securely require an anchor. We propose an anchor-less solution that takes some ideas from the host identity protocol. We then show how the idea of transferring endpoints simultaneously can be tackled without introducing timeouts as the session initiation protocol currently does.

  3. On the Theory of Ground Anchors

    DTIC Science & Technology

    1975-01-01

    AD/A-O06 582 ON THE THEORY OF GROUND ANCHORS COLD REGIONS RESEARCH AND ENGINEERING LABORATORY JANUARY 1975 DISTRIBUTED BY: National Tocnical -Intonal...ANCHORS Austin Kovacs, Scott Bicuin Bruce McKelvy and Herman Colligan January 1975 PREPARED FOR U.S. ARMY MATERIL’ COMMAND DA PROJECT IT062112A 130...applications as the tie-backs for retaining walls and bulkheads and in foundations subjected to wind, explosions, earthquakes and thermally induced lateral

  4. Lash Transported Anchor for a Tanker Mooring.

    DTIC Science & Technology

    1980-09-01

    comparable catenary - moored terminal facility is estimated to require an installation time of about 14 days. A Single Anchor Leg Mooring for the OBFS...installing the anchor. A maximum horizontal force of 222 kips (from model tests) on a catenary moored 50,000-dwt tanker in 65 ft water depth with a 4...completed in less than 7 days. A comparable catenary -moored terminal facility is estimated to required an installation time of about 14 days

  5. Experimental and theoretical analysis of CFRP reinforced concrete beam anchored by CF anchors

    NASA Astrophysics Data System (ADS)

    Zhuang, Ning; Ma, Ye-ming; Dong, Hong-han; Chen, Da

    2017-04-01

    Carbon fiber-reinforced polymer (CFRP) sheets is used to strengthen RC members widely. However, in the actual projects, premature separation of the CFRP sheet from the concrete surface is observed frequently, key issue in CFRP application is the performance of the connection between the CFRP sheet and the peripheral RC members. This paper presented the results of an experimental study to investigate mechanical properties of carbon fiber (CF) anchor dowels, a new CFRP anchoring method, and based on the experimental results, obtained the bearing capacity calculation formula of concrete beam strengthened with CFRP anchoring by carbon fiber anchor dowels .

  6. Multi-scale needle-network model of complex dendritic microstructure formation

    NASA Astrophysics Data System (ADS)

    Tourret, Damien; Karma, Alain

    2012-07-01

    We present a novel multi-scale Dendritic Needle Network (DNN) approach in order to model well-developed highly-ramified dendritic microstructures on the coarser scale of several crystal grains while retaining a faithful quantitative description of the transient dynamics of individual dendritic branches. This approach is intended to bridge the scale gap between phase-field and cellular automaton methods. The dynamics of each needle-like branch, characterized by its tip velocity V and radius ρ, is fixed by two conditions: (i) on the inner tip scale, a standard microscopic solvability condition relates ρ2V to the strength of surface tension anisotropy, and (ii) on the outer diffusion length scale, a flux balance condition relates the product ρV2 to a flux intensity factor extracted from a contour integral analogous to the J-integral of fracture mechanics. The method is tested for low supersaturation and reproduces the analytical solutions for both early stage and steady state growth dynamics. The results are directly compared with a quantitative phase-field simulation for an experimentally relevant supersaturation. We present as well an illustrative simulation for highly branched polycrystalline growth. This model should permit to investigate the macroscale grain evolution through the dynamics of individual primary dendrites and higher-order branches, controlled by both the intragrain history-dependent selection and the intergrain dendrite interactions.

  7. Improving performance by anchoring movement and "nerves".

    PubMed

    Iso-Ahola, Seppo E; Dotson, Charles O; Jagodinsky, Adam E; Clark, Lily C; Smallwood, Lorraine L; Wilburn, Christopher; Weimar, Wendi H; Miller, Matthew W

    2016-10-01

    Golf's governing bodies' recent decision to ban all putting styles "anchoring one end of the club against the body" bridges an important practical problem with psychological theory. We report the first experiment testing whether anchoring provides technical and/or psychological advantage in competitive performance. Many "greats" of professional golf from Arnold Palmer and Jack Nicklaus to Tiger Woods have argued against anchoring, believing that it takes "nerves" out of competitive performance and therefore artificially levels the playing field. To shed more light on the issue, we tested participants' performance with anchored and unanchored putters under low and high pressure when controlling for the putter length. We found no statistically significant evidence for a technical advantage due to anchoring but a clear psychological advantage: participants who anchored their putters significantly outperformed unanchored counterparts under high, but not low, pressure. Results provide tentative evidence for the ban's justification from a competitive standpoint. However, before any definite conclusions can be made, more research is needed when using high-level golfers. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Anchoring effects on early autobiographical memories.

    PubMed

    Greenberg, Daniel L; Bishara, Anthony J; Mugayar-Baldocchi, Marino A

    2017-10-01

    Studies of childhood memory typically show that our earliest memories come from between three and four years of age. This finding is not universal, however. The age estimate varies across cultures and is affected by social influences. Research from the judgments and decision-making literature suggests that these estimates might also involve a judgment under uncertainty. Therefore, they might be susceptible to less social influences such as heuristics and biases. To investigate this possibility, we conducted two experiments that used anchoring paradigms to influence participants' estimates of their age during early autobiographical memories. In Experiment 1, participants answered either a high-anchor or a low-anchor question, and were warned that the anchor was uninformative; they went on to estimate their age during their earliest autobiographical memory. In Experiment 2, we replicated Experiment 1 and extended the design to examine additional early autobiographical memories. In both experiments, participants in the low-anchor condition gave earlier age estimates than those in the high-anchor condition. These results provide new insights into the methods used to investigate autobiographical memory. Moreover, they show that reports of early autobiographical memories can be influenced by a relatively light touch - a change to a single digit in a single question.

  9. A general entry to linear, dendritic and branched thiourea-linked glycooligomers as new motifs for phosphate ester recognition in water.

    PubMed

    Jiménez Blanco, José L; Bootello, Purificación; Ortiz Mellet, Carmen; Gutiérrez Gallego, Ricardo; García Fernández, José M

    2004-01-07

    A blockwise iterative synthetic strategy for the preparation of linear, dendritic and branched full-carbohydrate architectures has been developed by using sugar azido(carbamate) isothiocyanates as key templates; the presence of intersaccharide thiourea bridges provides anchoring points for hydrogen bond-directed molecular recognition of phosphate esters in water.

  10. 46 CFR 28.235 - Anchors and radar reflectors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Anchors and radar reflectors. 28.235 Section 28.235....235 Anchors and radar reflectors. (a) Each vessel must be fitted with an anchor(s) and chain(s), cable... rigged with gear that provides a radar signature from a distance of 6 miles, each nonmetallic hull vessel...

  11. 46 CFR 28.235 - Anchors and radar reflectors.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Anchors and radar reflectors. 28.235 Section 28.235....235 Anchors and radar reflectors. (a) Each vessel must be fitted with an anchor(s) and chain(s), cable... rigged with gear that provides a radar signature from a distance of 6 miles, each nonmetallic hull vessel...

  12. 46 CFR 28.235 - Anchors and radar reflectors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Anchors and radar reflectors. 28.235 Section 28.235....235 Anchors and radar reflectors. (a) Each vessel must be fitted with an anchor(s) and chain(s), cable... rigged with gear that provides a radar signature from a distance of 6 miles, each nonmetallic hull vessel...

  13. 46 CFR 28.235 - Anchors and radar reflectors.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Anchors and radar reflectors. 28.235 Section 28.235....235 Anchors and radar reflectors. (a) Each vessel must be fitted with an anchor(s) and chain(s), cable... rigged with gear that provides a radar signature from a distance of 6 miles, each nonmetallic hull vessel...

  14. 46 CFR 28.235 - Anchors and radar reflectors.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Anchors and radar reflectors. 28.235 Section 28.235....235 Anchors and radar reflectors. (a) Each vessel must be fitted with an anchor(s) and chain(s), cable... rigged with gear that provides a radar signature from a distance of 6 miles, each nonmetallic hull vessel...

  15. The Use of Comics-Based Cases in Anchored Instruction

    ERIC Educational Resources Information Center

    Kneller, Matthew F.

    2009-01-01

    The primary purpose of this research was to understand how comics fulfill the role of anchor in an anchored instruction learning environment. Anchored instruction addresses the inert knowledge problem through the use of realistic multimedia stories, or "anchors," that embed a problem and the necessary data to solve it within the narrative. In the…

  16. Further Study of the Choice of Anchor Tests in Equating

    ERIC Educational Resources Information Center

    Trierweiler, Tammy J.; Lewis, Charles; Smith, Robert L.

    2016-01-01

    In this study, we describe what factors influence the observed score correlation between an (external) anchor test and a total test. We show that the anchor to full-test observed score correlation is based on two components: the true score correlation between the anchor and total test, and the reliability of the anchor test. Findings using an…

  17. Further Study of the Choice of Anchor Tests in Equating

    ERIC Educational Resources Information Center

    Trierweiler, Tammy J.; Lewis, Charles; Smith, Robert L.

    2016-01-01

    In this study, we describe what factors influence the observed score correlation between an (external) anchor test and a total test. We show that the anchor to full-test observed score correlation is based on two components: the true score correlation between the anchor and total test, and the reliability of the anchor test. Findings using an…

  18. The Use of Comics-Based Cases in Anchored Instruction

    ERIC Educational Resources Information Center

    Kneller, Matthew F.

    2009-01-01

    The primary purpose of this research was to understand how comics fulfill the role of anchor in an anchored instruction learning environment. Anchored instruction addresses the inert knowledge problem through the use of realistic multimedia stories, or "anchors," that embed a problem and the necessary data to solve it within the narrative. In the…

  19. Catalyst-induced growth of carbon nanotubes on tips of cantilevers and nanowires

    DOEpatents

    Lee, James Weifu; Lowndes, Douglas H.; Merkulov, Vladimir I.; Eres, Gyula; Wei, Yayi; Greenbaum, Elias; Lee, Ida

    2004-06-29

    A method is described for catalyst-induced growth of carbon nanotubes, nanofibers, and other nanostructures on the tips of nanowires, cantilevers, conductive micro/nanometer structures, wafers and the like. The method can be used for production of carbon nanotube-anchored cantilevers that can significantly improve the performance of scaning probe microscopy (AFM, EFM etc). The invention can also be used in many other processes of micro and/or nanofabrication with carbon nanotubes/fibers. Key elements of this invention include: (1) Proper selection of a metal catalyst and programmable pulsed electrolytic deposition of the desired specific catalyst precisely at the tip of a substrate, (2) Catalyst-induced growth of carbon nanotubes/fibers at the catalyst-deposited tips, (3) Control of carbon nanotube/fiber growth pattern by manipulation of tip shape and growth conditions, and (4) Automation for mass production.

  20. Tipping point leadership.

    PubMed

    Kim, W Chan; Mauborgne, Renée

    2003-04-01

    When William Bratton was appointed police commissioner of New York City in 1994, turf wars over jurisdiction and funding were rife and crime was out of control. Yet in less than two years, and without an increase in his budget, Bratton turned New York into the safest large city in the nation. And the NYPD was only the latest of five law-enforcement agencies Bratton had turned around. In each case, he succeeded in record time despite limited resources, a demotivated staff, opposition from powerful vested interests, and an organization wedded to the status quo. Bratton's turnarounds demonstrate what the authors call tipping point leadership. The theory of tipping points hinges on the insight that in any organization, fundamental changes can occur quickly when the beliefs and energies of a critical mass of people create an epidemic movement toward an idea. Bratton begins by overcoming the cognitive hurdles that block organizations from recognizing the need for change. He does this by putting managers face-to-face with operational problems. Next, he manages around limitations on funds, staff, or equipment by concentrating resources on the areas that are most in need of change and that have the biggest payoffs. He meanwhile solves the motivation problem by singling out key influencers--people with disproportionate power due to their connections or persuasive abilities. Finally, he closes off resistance from powerful opponents. Not every CEO has the personality to be a Bill Bratton, but his successes are due to much more than his personality. He relies on a remarkably consistent method that any manager looking to turn around an organization can use to overcome the forces of inertia and reach the tipping point.

  1. Southern tip of Greenland

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Between the Arctic Ocean to the North and the Atlantic to the South, the island of Greenland remains covered in snow and ice throughout the year except for small portions of the coast line that thaw briefly in the summer. This true-color image from November 2, 2001, shows that even the southern tip of Greenland is back to winter, with even the rugged coastline snow-covered once again. About halfway up the western coastline, a phytoplankton bloom is occurring in the Davis Strait, coloring the water blue-green.

  2. Dendritic sidebranching in the three-dimensional symmetric model in the presence of noise

    NASA Technical Reports Server (NTRS)

    Langer, J. S.

    1987-01-01

    The time-dependent behavior of sidebranching deformations in the three-dimensional symmetric model of dendritic solidification is studied within a WKB approximation. Localized wave packets generated by pulses in the neighborhood of the tip are found to grow in amplitude and to spread and stretch as they move down the sides of the dendrite. This behavior is shown to imply that noise in the solidifying medium is selectively amplified in such a way as to produce a fluctuating train of sidebranches in qualitative agreement with experimental observations. A rough estimate indicates that purely thermal noise is probably not quite strong enough to fit the data.

  3. Regulation of Postsynaptic Structure and Function by an A-Kinase Anchoring Protein-Membrane Associated Guanylate Kinase Scaffolding Complex

    PubMed Central

    Robertson, Holly R.; Gibson, Emily S.; Benke, Timothy A.; Dell'Acqua, Mark L.

    2009-01-01

    A-kinase anchoring protein (AKAP) 79/150 is a scaffold protein found in dendritic spines that recruits the cAMP-dependent protein kinase (PKA) and protein phosphatase 2B-calcineurin (CaN) to membrane-associated guanylate kinase (MAGUK)-linked AMPA receptors (AMPAR) to control receptor phosphorylation and synaptic plasticity. However, AKAP79/150 may also coordinate regulation of AMPAR activity with spine structure directly through MAGUK binding and membrane-cytoskeletal interactions of its N-terminal targeting domain. In cultured hippocampal neurons, we observed that rat AKAP150 expression was low early in development but then increased coincident with spine formation and maturation. Overexpression of human AKAP79 in immature or mature neurons increased the number of dendritic filopodia and spines and enlarged spine area. However, RNAi knockdown of AKAP150 decreased dendritic spine area only in mature neurons. Importantly, AKAP79 overexpression in immature neurons increased AMPAR postsynaptic localization and activity. Neither the AKAP79 PKA nor CaN anchoring domain was required for increasing dendritic protrusion numbers, spine area or AMPAR synaptic localization; however, an internal region identified as the MAGUK binding domain was found to be essential as shown by expression of a MAGUK binding mutant that formed mainly filopodia and decreased AMPAR synaptic localization and activity. Expression of the AKAP79 N-terminal targeting domain alone also increased filopodia numbers but not spine area. Overall, these results demonstrate a novel structural role for AKAP79/150 where the N-terminal targeting domain induces dendritic filopodia and binding to MAGUKs promotes spine enlargement and AMPAR recruitment. PMID:19535604

  4. Anchors as Semantic Primes in Value Construction: An EEG Study of the Anchoring Effect.

    PubMed

    Ma, Qingguo; Li, Diandian; Shen, Qiang; Qiu, Wenwei

    2015-01-01

    Previous research regarding anchoring effects has demonstrated that human judgments are often assimilated to irrelevant information. Studies have demonstrated that anchors influence the economic valuation of various products and experiences; however, the cognitive explanations of this effect remain controversial, and its neural mechanisms have rarely been explored. In the current study, we conducted an electroencephalography (EEG) experiment to investigate the anchoring effect on willingness to accept (WTA) for an aversive hedonic experience and the role of anchors in this judgment heuristic. The behavioral results demonstrated that random numbers affect participants' WTA for listening to pieces of noise. The participants asked for higher pay after comparing their WTA with higher numbers. The EEG results indicated that anchors also influenced the neural underpinnings of the valuation process. Specifically, when a higher anchor number was drawn, larger P2 and late positive potential amplitudes were elicited, reflecting the anticipation of more intensive pain from the subsequent noise. Moreover, higher anchors induced a stronger theta band power increase compared with lower anchors when subjects listened to the noises, indicating that the participants felt more unpleasant during the actual experience of the noise. The levels of unpleasantness during both anticipation and experience were consistent with the semantic information implied by the anchors. Therefore, these data suggest that a semantic priming process underlies the anchoring effect in WTA. This study provides proof for the robustness of the anchoring effect and neural evidence of the semantic priming model. Our findings indicate that activated contextual information, even seemingly irrelevant, can be embedded in the construction of economic value in the brain.

  5. Anchors as Semantic Primes in Value Construction: An EEG Study of the Anchoring Effect

    PubMed Central

    Shen, Qiang; Qiu, Wenwei

    2015-01-01

    Previous research regarding anchoring effects has demonstrated that human judgments are often assimilated to irrelevant information. Studies have demonstrated that anchors influence the economic valuation of various products and experiences; however, the cognitive explanations of this effect remain controversial, and its neural mechanisms have rarely been explored. In the current study, we conducted an electroencephalography (EEG) experiment to investigate the anchoring effect on willingness to accept (WTA) for an aversive hedonic experience and the role of anchors in this judgment heuristic. The behavioral results demonstrated that random numbers affect participants’ WTA for listening to pieces of noise. The participants asked for higher pay after comparing their WTA with higher numbers. The EEG results indicated that anchors also influenced the neural underpinnings of the valuation process. Specifically, when a higher anchor number was drawn, larger P2 and late positive potential amplitudes were elicited, reflecting the anticipation of more intensive pain from the subsequent noise. Moreover, higher anchors induced a stronger theta band power increase compared with lower anchors when subjects listened to the noises, indicating that the participants felt more unpleasant during the actual experience of the noise. The levels of unpleasantness during both anticipation and experience were consistent with the semantic information implied by the anchors. Therefore, these data suggest that a semantic priming process underlies the anchoring effect in WTA. This study provides proof for the robustness of the anchoring effect and neural evidence of the semantic priming model. Our findings indicate that activated contextual information, even seemingly irrelevant, can be embedded in the construction of economic value in the brain. PMID:26439926

  6. Anticonical anchoring and surface transitions in a nematic liquid crystal.

    PubMed

    Faget, L; Lamarque-Forget, S; Martinot-Lagarde, Ph; Auroy, P; Dozov, I

    2006-11-01

    Recent works reported planar and conical azimuthally degenerated nematic anchorings. Here we predict an additional "anticonical" degenerated anchoring. Its energy presents two minima, parallel and perpendicular to the substrate plane, separated by a conical energy barrier. We realize this bistable anchoring on a grafted polymer brush and we observe temperature-driven transitions between the conical, planar, and anticonical degenerated anchorings. Under electric field we break the anticonical anchoring and switch between its bistable states.

  7. Anticonical anchoring and surface transitions in a nematic liquid crystal

    NASA Astrophysics Data System (ADS)

    Faget, L.; Lamarque-Forget, S.; Martinot-Lagarde, Ph.; Auroy, P.; Dozov, I.

    2006-11-01

    Recent works reported planar and conical azimuthally degenerated nematic anchorings. Here we predict an additional “anticonical” degenerated anchoring. Its energy presents two minima, parallel and perpendicular to the substrate plane, separated by a conical energy barrier. We realize this bistable anchoring on a grafted polymer brush and we observe temperature-driven transitions between the conical, planar, and anticonical degenerated anchorings. Under electric field we break the anticonical anchoring and switch between its bistable states.

  8. Sidebranching in the Dendritic Crystal Growth of Ammonium Chloride

    NASA Astrophysics Data System (ADS)

    Dougherty, Andrew

    2012-02-01

    We report measurements of the dendritic crystal growth of NH4Cl from supersaturated aqueous solution at small supersaturations. Sidebranch growth in this regime is challenging to model well, and the origin of the sidebranches is not fully understood. The early detection of sidebranches requires measurements of small deviations from the smooth steady state shape, but that shape is not well known at the intermediate distances relevant for sidebranch measurements. One model is that sidebranches result from the selective amplification of microscopic noise. We compare measurements of the sidebranch envelope with predictions of the noise-induced sidebranching model of Gonz'alez-Cinca, Ram'irez-Piscina, Casademunt, and Hern'andez-Machado [Phys Rev. E, 63, 051602 (2001)]. We find that the measured amplitude is somewhat larger than predicted, and the shape of the sidebranch envelope is also different. A second model is that sidebranches result from small oscillations of the tip. We have observed no such oscillations, but very small ones can not be ruled out. No measurement of the tip region can be completely free of contamination from early sidebranches, so it can be challenging to distinguish between an oscillating tip and a smooth tip with sidebranches starting nearby.

  9. Dendritic morphology of hippocampal and amygdalar neurons in adolescent mice is resilient to genetic differences in stress reactivity.

    PubMed

    Pillai, Anup G; de Jong, Danielle; Kanatsou, Sofia; Krugers, Harm; Knapman, Alana; Heinzmann, Jan-Michael; Holsboer, Florian; Landgraf, Rainer; Joëls, Marian; Touma, Chadi

    2012-01-01

    Many studies have shown that chronic stress or corticosterone over-exposure in rodents leads to extensive dendritic remodeling, particularly of principal neurons in the CA3 hippocampal area and the basolateral amygdala. We here investigated to what extent genetic predisposition of mice to high versus low stress reactivity, achieved through selective breeding of CD-1 mice, is also associated with structural plasticity in Golgi-stained neurons. Earlier, it was shown that the highly stress reactive (HR) compared to the intermediate (IR) and low (LR) stress reactive mice line presents a phenotype, with respect to neuroendocrine parameters, sleep architecture, emotional behavior and cognition, that recapitulates some of the features observed in patients suffering from major depression. In late adolescent males of the HR, IR, and LR mouse lines, we observed no significant differences in total dendritic length, number of branch points and branch tips, summated tip order, number of primary dendrites or dendritic complexity of either CA3 pyramidal neurons (apical as well as basal dendrites) or principal neurons in the basolateral amygdala. Apical dendrites of CA1 pyramidal neurons were also unaffected by the differences in stress reactivity of the animals; marginally higher length and complexity of the basal dendrites were found in LR compared to IR but not HR mice. In the same CA1 pyramidal neurons, spine density of distal apical tertiary dendrites was significantly higher in LR compared to IR or HR animals. We tentatively conclude that the dendritic complexity of principal hippocampal and amygdala neurons is remarkably stable in the light of a genetic predisposition to high versus low stress reactivity, while spine density seems more plastic. The latter possibly contributes to the behavioral phenotype of LR versus HR animals.

  10. Gas only nozzle fuel tip

    DOEpatents

    Bechtel, William Theodore; Fitts, David Orus; DeLeonardo, Guy Wayne

    2002-01-01

    A diffusion flame nozzle gas tip is provided to convert a dual fuel nozzle to a gas only nozzle. The nozzle tip diverts compressor discharge air from the passage feeding the diffusion nozzle air swirl vanes to a region vacated by removal of the dual fuel components, so that the diverted compressor discharge air can flow to and through effusion holes in the end cap plate of the nozzle tip. In a preferred embodiment, the nozzle gas tip defines a cavity for receiving the compressor discharge air from a peripheral passage of the nozzle for flow through the effusion openings defined in the end cap plate.

  11. Monitoring ground anchor using non-destructive ground anchor integrity test (NDT-GRANIT)

    SciTech Connect

    Robbany, Z. Handayani, G.

    2015-09-30

    Monitoring at ground anchor commonly uses a pull out test method, therefor we developing a non-destructive ground anchor integrity testing (NDT-GRANIT). NDT-GRANIT using the principle of seismic waves that have been modified into form of sweep signal, the signal will be demodulated, filtered, and Fourier transformation (inverse discrete Fourier transform) so the data can be interpreted reflected wave from the ground anchor. The method was applied to determine whether the ground anchor still gripped in the subsurface by looking the attenuation of the wave generated sources. From the result we can see that ground anchor does not grip. To validate the results of the comparison method of measurement used pile integrity test.

  12. Polymer's anchoring behavior in liquid crystal cells

    NASA Astrophysics Data System (ADS)

    Cui, Yue

    The current dissertation mainly discusses about the polymers anchoring behavior in liquid crystal cells in two aspects: surface interaction and bulk interaction. The goal of the research is to understand the fundamental physics of anchoring strength and apply the knowledge to liquid crystal display devices. Researchers proposed two main contributors to the surface anchoring strength: the micro grooves generated by external force and the polymer chain's alignment. Both of them has experimental proofs. In the current study, explorations were made to understand the mechanisms of surface anchoring strength and easy axis of surface liquid crystal provided by rubbed polymer alignment layer. The work includes not only the variation of the alignment layer itself such as thickness(Chapter 3) and polymer side chain (Chapter 5), but also the variation of external conditions such as temperature (Chapter 4) and rubbing condition (Chapter 6). To determine the polar and azimuthal anchoring strengths, Rapini-Papoular's expression was applied. However, it was discovered that higher order terms may be required in order to fit the experimental result or theoretically predict unique anchoring behaviors (Chapter 2, Chapter 6). SEM and AFM technologies were introduced to gather the actual structures of polymer alignment layer and extrapolate the alignment of liquid crystal in a micro scale. The result shows that the anchoring strength can be adjusted by the layer thickness, side chain structure, while the easy axis direction can be adjusted by a second rubbing direction. In addition, different anchoring conditions combined with liquid crystal's elastic energy can generate quite different forms of liquid crystals (Chapter 7). In the study of bulk alignment, the main contrition from the current dissertation is applying the understanding of anchoring behavior to optimizing actual switchable devices. Conventional PDLC performance can be tuned with the knowledge of the polymer and the liquid

  13. Benchmark experiments and numerical modelling of the columnar-equiaxed dendritic growth in the transparent alloy Neopentylglycol-(d)Camphor

    NASA Astrophysics Data System (ADS)

    Sturz, L.; Wu, M.; Zimmermann, G.; Ludwig, A.; Ahmadein, M.

    2015-06-01

    Solidification benchmark experiments on columnar and equiaxed dendritic growth, as well as the columnar-equiaxed transition have been carried out under diffusion-dominated conditions for heat and mass transfer in a low-gravity environment. The system under investigation is the transparent organic alloy system Neopentylglycol-37.5wt.-%(d)Camphor, processed aboard a TEXUS sounding rocket flight. Solidifications was observed by standard optical methods in addition to measurements of the thermal fields within the sheet like experimental cells of 1 mm thickness. The dendrite tip kinetic, primary dendrite arm spacing, temporal and spatial temperature evolution, columnar tip velocity and the critical parameters at the CET have been analysed. Here we focus on a detailed comparison of the experiment “TRACE” with a 5-phase volume averaging model to validate the numerical model and to give insight into the corresponding physical mechanisms and parameters leading to CET. The results are discussed in terms of sensitivity versus numerical parameters.

  14. GPI-anchor and GPI-anchored protein expression in PMM2-CDG patients

    PubMed Central

    2013-01-01

    Background Mutations in PMM2 impair phosphomannomutase-2 activity and cause the most frequent congenital disorder of glycosylation, PMM2-CDG. Mannose-1-phosphate, that is deficient in this disorder, is also implicated in the biosynthesis of glycosylphosphatidyl inositol (GPI) anchors. Objective To evaluate whether GPI-anchor and GPI-anchored proteins are defective in PMM2-CDG patients. Methods The expression of GPI-anchor and seven GPI-anchored proteins was evaluated by flow cytometry in different cell types from twelve PMM2-CDG patients. Additionally, neutrophil CD16 and plasma hepatic proteins were studied by Western blot. Transferrin glycoforms were evaluated by HPLC. Results Patients and controls had similar surface expression of GPI-anchor and most GPI-anchored proteins. Nevertheless, patients displayed a significantly diminished binding of two anti-CD16 antibodies (3G8 and KD1) to neutrophils and also of anti-CD14 (61D3) to monocytes. Interestingly, CD16 immunostaining and asialotransferrin levels significantly correlated with patients’ age. Analysis by flow cytometry of CD14 with MΦP9, and CD16 expression in neutrophils by Western blot using H-80 ruled out deficiencies of these antigens. Conclusions PMM2 mutations do not impair GPI-anchor or GPI-anchored protein expression. However, the glycosylation anomalies caused by PMM2 mutations might affect the immunoreactivity of monoclonal antibodies and lead to incorrect conclusions about the expression of different proteins, including GPI-anchored proteins. Neutrophils and monocytes are sensitive to PMM2 mutations, leading to abnormal glycosylation in immune receptors, which might potentially affect their affinity to their ligands, and contribute to infection. This study also confirms less severe hypoglycosylation defects in older PMM2-CDG patients. PMID:24139637

  15. Global up-regulation of microtubule dynamics and polarity reversal during regeneration of an axon from a dendrite.

    PubMed

    Stone, Michelle C; Nguyen, Michelle M; Tao, Juan; Allender, Dana L; Rolls, Melissa M

    2010-03-01

    Axon regeneration is crucial for recovery after trauma to the nervous system. For neurons to recover from complete axon removal they must respecify a dendrite as an axon: a complete reversal of polarity. We show that Drosophila neurons in vivo can convert a dendrite to a regenerating axon and that this process involves rebuilding the entire neuronal microtubule cytoskeleton. Two major microtubule rearrangements are specifically induced by axon and not dendrite removal: 1) 10-fold up-regulation of the number of growing microtubules and 2) microtubule polarity reversal. After one dendrite reverses its microtubules, it initiates tip growth and takes on morphological and molecular characteristics of an axon. Only neurons with a single dendrite that reverses polarity are able to initiate tip growth, and normal microtubule plus-end dynamics are required to initiate this growth. In addition, we find that JNK signaling is required for both the up-regulation of microtubule dynamics and microtubule polarity reversal initiated by axon injury. We conclude that regulation of microtubule dynamics and polarity in response to JNK signaling is key to initiating regeneration of an axon from a dendrite.

  16. Global Up-Regulation of Microtubule Dynamics and Polarity Reversal during Regeneration of an Axon from a Dendrite

    PubMed Central

    Stone, Michelle C.; Nguyen, Michelle M.; Tao, Juan; Allender, Dana L.

    2010-01-01

    Axon regeneration is crucial for recovery after trauma to the nervous system. For neurons to recover from complete axon removal they must respecify a dendrite as an axon: a complete reversal of polarity. We show that Drosophila neurons in vivo can convert a dendrite to a regenerating axon and that this process involves rebuilding the entire neuronal microtubule cytoskeleton. Two major microtubule rearrangements are specifically induced by axon and not dendrite removal: 1) 10-fold up-regulation of the number of growing microtubules and 2) microtubule polarity reversal. After one dendrite reverses its microtubules, it initiates tip growth and takes on morphological and molecular characteristics of an axon. Only neurons with a single dendrite that reverses polarity are able to initiate tip growth, and normal microtubule plus-end dynamics are required to initiate this growth. In addition, we find that JNK signaling is required for both the up-regulation of microtubule dynamics and microtubule polarity reversal initiated by axon injury. We conclude that regulation of microtubule dynamics and polarity in response to JNK signaling is key to initiating regeneration of an axon from a dendrite. PMID:20053676

  17. Modeling of convection, temperature distribution and dendritic growth in glass-fluxed nickel melts

    NASA Astrophysics Data System (ADS)

    Gao, Jianrong; Kao, Andrew; Bojarevics, Valdis; Pericleous, Koulis; Galenko, Peter K.; Alexandrov, Dmitri V.

    2017-08-01

    Melt flow is often quoted as the reason for a discrepancy between experiment and theory on dendritic growth kinetics at low undercoolings. But this flow effect is not justified for glass-fluxed melts where the flow field is weaker. In the present work, we modeled the thermal history, flow pattern and dendritic structure of a glass-fluxed nickel sample by magnetohydrodynamics calculations. First, the temperature distribution and flow structure in the molten and undercooled melt were simulated by reproducing the observed thermal history of the sample prior to solidification. Then the dendritic structure and surface temperature of the recalescing sample were simulated. These simulations revealed a large thermal gradient crossing the sample, which led to an underestimation of the real undercooling for dendritic growth in the bulk volume of the sample. By accounting for this underestimation, we recalculated the dendritic tip velocities in the glass-fluxed nickel melt using a theory of three-dimensional dendritic growth with convection and concluded an improved agreement between experiment and theory.

  18. Crossed receptive field components and crossed dendrites in cat sacrocaudal dorsal horn.

    PubMed

    Gladfelter, W E; Millecchia, R J; Pubols, L M; Sonty, R V; Ritz, L A; Covalt-Dunning, D; Culberson, J; Brown, P B

    1993-10-01

    The hypothesis that sacrocaudal dorsal horn neurons with crossed receptive field components on the tail have dendrites which cross to the contralateral dorsal horn was tested in a combined electrophysiological and morphological study. Dorsal horn cells in the sacrocaudal spinal cord of anesthetized cats were penetrated with horseradish peroxidase-filled microelectrodes. After mapping their low threshold mechanoreceptive fields, cells were iontophoretically injected with horseradish peroxidase. A sample of 16 well-stained cells was obtained in laminae III and IV. Cells with receptive fields crossing the dorsal midline of the tail (n = 8) had somata in the lateral ipsilateral dorsal horn, and some of these cells (5/8) had dendrites which crossed to the lateral contralateral dorsal horn. Cells with receptive fields spanning the ventral midline (n = 2) were located near the center of the fused dorsal horn, and one of these had bilateral dendrites in this region. Cells with receptive fields on the lateral tail, crossing neither the dorsal nor the ventral midline (n = 6), had cell bodies in the middle of the ipsilateral dorsal horn; half had only ipsilateral dendrites, and half had crossed dendritic branches. Although the relationship between cell receptive field (RF) location (RF center, expressed as distance from tips of toes) and mediolateral location of the cell body was statistically significant, the correlation between crossed RF components and crossed dendritic branches was not significant.

  19. Dendritic oligoguanidines as intracellular translocators.

    PubMed

    Chung, Hyun-Ho; Harms, Guido; Seong, Churl Min; Choi, Byung Hyune; Min, Changhee; Taulane, Joseph P; Goodman, Murray

    2004-01-01

    A series of polyguanidylated dendritic structures that can be used as molecular translocators have been designed and synthesized based on nonpeptide units. The dendritic oligoguanidines conjugated with fluorescein or with a green fluorescent protein (GFP) mutant as cargos were isolated and characterized. Quantification and time-course analyses of the cellular uptake of the conjugates using HeLa S3 and human cervical carcinoma cells reveal that the polyguanidylated dendrimers have comparable translocation efficiency to the Tat(49-57) peptide. Furthermore, the deconvolution microscopy image analysis shows that they are located inside the cells. These results clearly show that nonlinear, branched dendritic oligoguanidines are capable of translocation through the cell membrane. This work also demonstrates the potential of these nonpeptidic dendritic oligoguanidines as carriers for intracellular delivery of small molecule drugs, bioactive peptides, and proteins. Copyright 2004 Wiley Periodicals, Inc. Biopolymers (Pept Sci), 2004

  20. Optimal Current Transfer in Dendrites

    PubMed Central

    Bird, Alex D.

    2016-01-01

    Integration of synaptic currents across an extensive dendritic tree is a prerequisite for computation in the brain. Dendritic tapering away from the soma has been suggested to both equalise contributions from synapses at different locations and maximise the current transfer to the soma. To find out how this is achieved precisely, an analytical solution for the current transfer in dendrites with arbitrary taper is required. We derive here an asymptotic approximation that accurately matches results from numerical simulations. From this we then determine the diameter profile that maximises the current transfer to the soma. We find a simple quadratic form that matches diameters obtained experimentally, indicating a fundamental architectural principle of the brain that links dendritic diameters to signal transmission. PMID:27145441

  1. Can dendritic cells see light?

    NASA Astrophysics Data System (ADS)

    Chen, Aaron C.-H.; Huang, Ying-Ying; Sharma, Sulbha K.; Hamblin, Michael R.

    2010-02-01

    There are many reports showing that low-level light/laser therapy (LLLT) can enhance wound healing, upregulate cell proliferation and has anti-apoptotic effects by activating intracellular protective genes. In the field of immune response study, it is not known with any certainty whether light/laser is proinflammatory or anti-inflammatory. Increasingly in recent times dendritic cells have been found to play an important role in inflammation and the immunological response. In this study, we try to look at the impact of low level near infrared light (810-nm) on murine bone-marrow derived dendritic cells. Changes in surface markers, including MHC II, CD80 and CD11c and the secretion of interleukins induced by light may provide additional evidence to reveal the mystery of how light affects the maturation of dendritic cells as well how these light-induced mature dendritic cells would affect the activation of adaptive immune response.

  2. Anchoring in rhythmic in-phase and antiphase visuomotor tracking.

    PubMed

    Roerdink, Melvyn; Bank, Paulina J M; Peper, C E; Beek, Peter J

    2013-04-01

    Rhythmic limb movements are often anchored at particular points in the movement cycle. Anchoring may reveal essential task-specific information for motor control. We examined the effect of tracking mode (in-phase, antiphase) and gaze direction (left, right) on anchoring in visuomotor tracking with and without concurrent visual feedback of the hand movement. For in-phase tracking, anchoring was observed at the foveated reversal point whereas for antiphase tracking anchoring was observed at both reversals, suggesting the presence of two reference points instead of one. Anchoring at the foveated reversal reflected gaze anchoring (i.e., coalignment of hand and gaze) while anchoring at the nonfoveated reversal reflected visuomotor synchronization (i.e., the hand was steered to the nonfoveated reversal coincident with a target reversal at the point of gaze). We propose that the number and location of anchor points play a crucial role in the underlying control by providing reference values for error correction processes.

  3. Roles of actin cytoskeleton for regulation of chloroplast anchoring.

    PubMed

    Sakai, Yuuki; Takagi, Shingo

    2017-08-22

    Chloroplasts are known to maintain specific intracellular distribution patterns under specific environmental conditions, enabling the optimal performance of photosynthesis. To this end, chloroplasts are anchored in the cortical cytoplasm. In leaf epidermal cells of aquatic monocot Vallisneria, we recently demonstrated that the anchored chloroplasts are rapidly de-anchored upon irradiation with high-intensity blue light and that the process is probably mediated by the blue-light receptor phototropins. Chloroplast de-anchoring is a necessary step rendering the previously anchored chloroplasts mobile to allow their migration. In this article, based on the results obtained in Vallisneria together with those in other plant species, we briefly discussed possible modes of regulation of chloroplast anchoring and de-anchoring by actin cytoskeleton. The topics include roles of photoreceptor systems, actin-filament-dependent and -independent chloroplast anchoring, and independence of chloroplast de-anchoring from actomyosin and microtubule systems.

  4. Sidebranching in the Dendritic Crystal Growth of Ammonium Chloride

    NASA Astrophysics Data System (ADS)

    Dougherty, Andrew; Stinner, Franklin

    2010-03-01

    We report new measurements of the dendritic crystal growth of NH4Cl from supersaturated aqueous solution. We report the first measurement of the capillary length d0 to be approximately 2 x10-4 μm. For growth at small dimensionless supersaturations δ on the order of 0.005, we have estimated the stability constant &*circ; to be approximately 0.008. The origin of the sidebranches in dendritic growth is not fully understood, but one model is that they result from the selective amplification of microscopic noise. We will compare measurements of the sidebranch envelope with predictions of the noise-induced sidebranching model of Gonz'alez-Cinca, Ram'irez-Piscina, Casademunt, and Hern'andez-Machado [Phys Rev. E, 63, 051602 (2001)]. A second model is that sidebranches result from small oscillations of the tip. We have observed no such oscillations, but very small ones can not be ruled out. Given the finite experimental resolution, no measurement of the tip region can be completely free of contamination from early sidebranches. We will discuss this and other experimental challenges that need to be overcome before we can understand the origin of sidebranches.

  5. Priming and Anchoring Effects in Visualizations.

    PubMed

    Valdez, Andre Calero; Ziefle, Martina; Sedlmair, Michael

    2017-08-30

    We investigate priming and anchoring effects on perceptual tasks in visualization. Priming or anchoring effects depict the phenomena that stimulus might influence subsequent human judgements on a perceptual level, or on a cognitive level by providing a frame of reference. Using visual class separability in scatterplots as an example task, we performed a set of five studies to investigate the potential existence of priming and anchoring effects. Our findings show that-under certain circumstances-such effects indeed exist. In other words, humans judge class separability of the same scatterplot differently depending on the scatterplot(s) they have seen before. These findings inform future work on better understanding and more accurately modeling human perception of visual patterns.

  6. Fibre-Reinforced Adhesive for Structure Anchoring

    NASA Astrophysics Data System (ADS)

    Barnat, J.; Bajer, M.

    2015-11-01

    The topic of this paper is the glue-concrete interface of bonded anchors loaded by tension force. The paper is closely focused on bond strength experiments using high strength concrete up to class C50/60 or higher together with pure epoxy resin and fibre-reinforced resin. The goal of this research is to find the limits of the effective use of such glue types in high performance concrete, and also to verify the most commonly used design methods for bonded anchors. The presented research includes experimental analysis of the glue-concrete interface and the influence of its parameters on anchor behaviour. The presented analysis shows some problems of the 'separated failure modes' approach and also presents experimentally verified bond strength values obtained for the currently most widespread glue types. Results of fibre reinforced epoxy resin are also presented in this paper.

  7. Biomedical applications of glycosylphosphatidylinositol-anchored proteins

    PubMed Central

    Heider, Susanne; Dangerfield, John A.

    2016-01-01

    Glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) use a unique posttranslational modification to link proteins to lipid bilayer membranes. The anchoring structure consists of both a lipid and carbohydrate portion and is highly conserved in eukaryotic organisms regarding its basic characteristics, yet highly variable in its molecular details. The strong membrane targeting property has made the anchors an interesting tool for biotechnological modification of lipid membrane-covered entities from cells through extracellular vesicles to enveloped virus particles. In this review, we will take a closer look at the mechanisms and fields of application for GPI-APs in lipid bilayer membrane engineering and discuss their advantages and disadvantages for biomedicine. PMID:27542385

  8. The Isothermal Dendritic Growth Experiment

    NASA Technical Reports Server (NTRS)

    Glicksman, M. E.; Koss, M. B.; Malarik, D. C.

    1998-01-01

    The growth of dendrites is one of the commonly observed forms of solidification encountered when metals and alloys freeze under low thermal gradients, as occurs in most casting and welding processes. In engineering alloys, the details of the dendritic morphology directly relates to important material responses and properties. Of more generic interest, dendritic growth is also an archetypical problem in morphogenesis, where a complex pattern evolves from simple starting conditions. Thus, the physical understanding and mathematical description of how dendritic patterns emerge during the growth process are of interest to both scientists and engineers. The Isothermal Dendritic Growth Experiment (IDGE) is a basic science experiment designed to measure, for a fundamental test of theory, the kinetics and morphology of dendritic growth without complications induced by gravity-driven convection. The IDGE, a collaboration between Rensselaer Polytechnic Institute, in Troy NY, and NASA's Lewis Research Center (LeRC) was developed over a ten year period from a ground-based research program into a space flight experiment. Important to the success of this flight experiment was provision of in situ near-real-time teleoperations during the spaceflight experiment.

  9. Brilliant Writing Tips for Students

    ERIC Educational Resources Information Center

    Copus, Julia

    2010-01-01

    With tips on punctuation, style, grammar and essay structure, this handy guide provides succinct and practical guidance on students most common areas of concern in their written work. Each tip is supplemented by authentic examples of student writing, suggested re-writes, and appropriate self-help exercises. This book contains four parts. Part I:…

  10. Tips for Mental Health Interpretation

    ERIC Educational Resources Information Center

    Whitsett, Margaret

    2008-01-01

    This paper offers tips for working with interpreters in mental health settings. These tips include: (1) Using trained interpreters, not bilingual staff or community members; (2) Explaining "interpreting procedures" to the providers and clients; (3) Addressing the stigma associated with mental health that may influence interpreters; (4) Defining…

  11. The Macro - TIPS Course Package.

    ERIC Educational Resources Information Center

    Heriot-Watt Univ., Edinburgh (Scotland). Esmee Fairbairn Economics Research Centre.

    The TIPS (Teaching Information Processing System) Course Package was designed to be used with the Macro-Games Course Package (SO 011 930) in order to train college students to apply the tools of economic analysis to current problems. TIPS is used to provide feedback and individualized assignments to students, as well as information about the…

  12. Development of a simultaneous cryo-anchoring and radiofrequency ablation catheter for percutaneous treatment of mitral valve prolapse.

    PubMed

    Boronyak, Steven M; Merryman, W David

    2012-09-01

    Mitral valve prolapse (MVP) is one subtype of mitral valve (MV) disease and is often characterized by enlarged leaflets that are thickened and have disrupted collagen architecture. The increased surface area of myxomatous leaflets with MVP leads to mitral regurgitation, and there is need for percutaneous treatment options that avoid open-chest surgery. Radiofrequency (RF) ablation is one potential therapy in which resistive heating can be used to reduce leaflet size via collagen contracture. One challenge of using RF ablation to percutaneously treat MVP is maintaining contact between the RF ablation catheter tip and a functioning MV leaflet. To meet this challenge, we have developed a RF ablation catheter with a cryogenic anchor for attachment to leaflets in order to apply RF ablation. We demonstrate the effectiveness of the dual-energy catheter in vitro by examining changes in leaflet biaxial compliance, thermal distribution with infrared (IR) imaging, and cryogenic anchor strength. We report that 1250 J of RF energy with cryo-anchoring reduced the determinant of the deformation gradient tensor at systolic loading by 23%. IR imaging revealed distinct regions of cryo-anchoring and tissue ablation, demonstrating that the two modalities do not counteract one another. Finally, cryogenic anchor strength to the leaflet was reduced but still robust during the application of RF energy. These results indicate that a catheter having combined RF ablation and cryo-anchoring provides a novel percutaneous treatment strategy for MVP and may also be useful for other percutaneous procedures where anchored ablation would provide more precise spatial control.

  13. Multiple magnetic microrobot control using electrostatic anchoring

    NASA Astrophysics Data System (ADS)

    Pawashe, Chytra; Floyd, Steven; Sitti, Metin

    2009-04-01

    Addressing power and control to individual untethered microrobots is a challenge for small-scale robotics. We present a 250×130×100 μm3 magnetic robot wirelessly driven by pulsed external magnetic fields. An induced stick-slip motion results in translation speeds over 8 mm/s. Control of multiple robots is achieved by an array of addressable electrostatic anchoring pads on the surface, which selectively fixes microrobots, preventing translation. We demonstrate control of two microrobots in both uncoupled individual motion and coupled symmetric motion. An estimated anchoring force of 23.0 μN is necessary to effectively fix each microrobot.

  14. Pattern selection in a boundary-layer model of dendritic growth in the presence of impurities

    NASA Technical Reports Server (NTRS)

    Karma, A.; Kotliar, B. G.

    1985-01-01

    Presently analyzed, in the context of a boundary-layer model, is the problem of pattern selection in dendritic growth in a situation where impurities are present in the undercooled liquid. It is found that the tip-velocity selection criterion that has been proposed recently for the geometrical model and the boundary-layer model of a pure substance can be extended, in a nontrivial way, to this more complex situation where two coupled diffusion fields (temperature and solute) determine the interface dynamics. This model predicts a sharp enhancement of tip velocity in good qualitative agreement with experiment. This agreement is consistent with the conjecture that a solvability condition can be used to determine the operating point of the dendrite in the full nonlocal problem.

  15. Bond strength of glass fiber reinforced plastics (GFRP) grouted anchors

    SciTech Connect

    Bellavance, E.; Xu, H.; Benmokrane, B.

    1995-11-01

    This paper describes the results of laboratory and field pull-out tests on cement grouted glass fiber reinforced plastic (GFRP) anchors. As an alternative for grouted steel anchors, GFRP bars have many advantages over steel tendons, and can avoid corrosion and some difficulties in transportation, handling, and installation. Three types of 36 GFRP anchors and 20 steel anchors installed in three types of host media: steel pipe, concrete block, and rock mass were tested in the laboratory as well as in the field. The bond strength, load carrying capacity, load-displacement behavior, and critical bond length of cement grouted GFRP anchors were examined in comparison with conventional steel anchors.

  16. Involvement of SARA in Axon and Dendrite Growth.

    PubMed

    Arias, Cristina Isabel; Siri, Sebastián Omar; Conde, Cecilia

    2015-01-01

    SARA (Smad Anchor for Receptor Activation) plays a crucial role in Rab5-mediated endocytosis in cell lines localizing to early endosomes where it regulates morphology and function. Here, we analyzed the role of SARA during neuronal development and tested whether it functions as a regulator of endocytic trafficking of selected axonal and membrane proteins. Suppression of SARA perturbs the appearance of juxtanuclear endocytic recycling compartments and the neurons show long axons with large growth cones. Furthermore, surface distribution of the cell adhesion molecule L1 in axons and the fusion of vesicles containing transferring receptor (TfR) in dendrites were increased in neurons where SARA was silenced. Conversely, SARA overexpression generated large early endosomes and reduced neurite outgrowth. Taken together, our findings suggest a significant contribution of SARA to key aspects of neuronal development, including neurite formation.

  17. Involvement of SARA in Axon and Dendrite Growth

    PubMed Central

    Arias, Cristina Isabel; Siri, Sebastián Omar; Conde, Cecilia

    2015-01-01

    SARA (Smad Anchor for Receptor Activation) plays a crucial role in Rab5-mediated endocytosis in cell lines localizing to early endosomes where it regulates morphology and function. Here, we analyzed the role of SARA during neuronal development and tested whether it functions as a regulator of endocytic trafficking of selected axonal and membrane proteins. Suppression of SARA perturbs the appearance of juxtanuclear endocytic recycling compartments and the neurons show long axons with large growth cones. Furthermore, surface distribution of the cell adhesion molecule L1 in axons and the fusion of vesicles containing transferring receptor (TfR) in dendrites were increased in neurons where SARA was silenced. Conversely, SARA overexpression generated large early endosomes and reduced neurite outgrowth. Taken together, our findings suggest a significant contribution of SARA to key aspects of neuronal development, including neurite formation. PMID:26405814

  18. Follow-on Research Activities for the Rensselaer Isothermal Dendritic Growth Experiment (RIDGE)

    NASA Technical Reports Server (NTRS)

    LaCombe, J. C.; Koss, M. B.; Lupulescu, A. O.; Frei, J. E.; Giummarra, C.; Glicksman, M. E.

    2001-01-01

    The RIDGE effort continues the aegis of the earlier, NASA-sponsored, Isothermal Dendritic Growth Experiment (IDGE) series of experiments through the continued analysis of microgravity data acquired during these earlier space flights. The preliminary observations presented here demonstrate that there are significant differences between SCN and the more anisotropic PVA dendrites. The side branch structure becomes amplified only further behind the tip, and the interface shape is generally wider (i.e. more hyperbolic than parabolic) in PVA than in SCN. These characteristics are seen to affect the process of heat transport. Additionally, the dendrites grown during the fourth United States Microgravity Payload (USMP-4) exhibit time-dependent growth characteristics and may not always have reached steady-state growth during the experiment.

  19. Dendrite characteristics in directionally solidified Pb-8 pct Au and Pb-3 pct Pd alloys

    NASA Technical Reports Server (NTRS)

    Tewari, S. N.

    1986-01-01

    An investigation of Pb-8 pct Au and Pb-3 pct Pd alloy specimens which have been partially directionally solidified and then quenched is performed in order to characterize their dendritic microstructural details and solute composition profiles. A controlled sectioning technique is employed to measure dendrite tip radii. It is found that most of the observed behavior is predicted quite well by a modification of the Burden and Hunt (1974) model proposed by Laxmanan (1984), in addition to the models based on the marginal stability approach. Results indicate that quantitative comparison of the primary arm spacing measurements can not form the basis of distinguishing among the various dendrite growth models in a positive temperature gradient.

  20. Growth of 'dizzy dendrites' in a random field of foreign particles

    NASA Astrophysics Data System (ADS)

    Gránásy, László; Pusztai, Tamás; Warren, James A.; Douglas, Jack F.; Börzsönyi, Tamás; Ferreiro, Vincent

    2003-02-01

    Microstructure plays an essential role in determining the properties of crystalline materials. A widely used method to influence microstructure is the addition of nucleating agents. Observations on films formed from clay-polymer blends indicate that particulate additives, in addition to serving as nucleating agents, may also perturb crystal growth, leading to the formation of irregular dendritic morphologies. Here we describe the formation of these 'dizzy dendrites' using a phase-field theory, in which randomly distributed foreign particle inclusions perturb the crystallization by deflecting the tips of the growing dendrite arms. This mechanism of crystallization, which is verified experimentally, leads to a polycrystalline structure dependent on particle configuration and orientation. Using computer simulations we demonstrate that additives of controlled crystal orientation should allow for a substantial manipulation of the crystallization morphology.

  1. Ideal site for ventricular anchoring of artificial chordae in mitral regurgitation.

    PubMed

    Weber, Alberto; Hurni, Samuel; Vandenberghe, Stijn; Wahl, Andreas; Aymard, Thierry; Vogel, Rolf; Carrel, Thierry

    2012-04-01

    Surgical treatment of mitral leaflet prolapse using artificial neochordae shows excellent outcomes. Upcoming devices attempt the same treatment in a minimally invasive way but target the left ventricular apex as an anchoring point, rather than the tip of the corresponding papillary muscle. In this study, cine cardiac magnetic resonance imaging was used to compare these 2 different anchoring positions and their dynamic relationship with the mitral leaflets. Eleven healthy volunteers (mean age, 31 years; 6 female; mean ejection fraction, 62%) were examined by cardiac magnetic resonance imaging (3 Tesla, cine steady free precession technique with retrospective gating), whereby dedicated software enabled assessment of the physiologic distances among 3 anchoring sites (anterior papillary muscle, posterior papillary muscle, and apex) and the plane of the mitral annulus at the level of leaflet coaptation. These distances were measured in systole and diastole, and the performance of virtual neochordae was analyzed for the 3 potential anchoring sites. Length difference between systole and diastole for the 3 measured distances were 0.19 ± 0.11 cm (5.9% ± 3.4%) for the anterior papillary muscle, 0.19 ± 0.09 cm (6.7% ± 3.6%) for the posterior papillary muscle, and 1.52 ± 0.18 cm (17.8% ± 2.8%) for the left ventricular apex (P = .001). Virtual neochordae between the leaflet and the left ventricular apex were first adjusted in systole to achieve leaflet coaptation. Leaflet tear in diastole can only be avoided if the width of the attached leaflet is larger than the systole-diastole length difference. On the other hand, if virtual neochordae are adjusted in diastole to avoid leaflet tear, residual leaflet prolapse during systole can result. Because the systole-diastole length difference for papillary muscle anchored chordae is smaller than for apical chordae by a factor 10, there is a strongly reduced risk of prolapse or tearing and the leaflet width is unimportant

  2. Nanostructured Tip-Shaped Biosensors: Application of Six Sigma Approach for Enhanced Manufacturing.

    PubMed

    Kahng, Seong-Joong; Kim, Jong-Hoon; Chung, Jae-Hyun

    2016-12-23

    Nanostructured tip-shaped biosensors have drawn attention for biomolecule detection as they are promising for highly sensitive and specific detection of a target analyte. Using a nanostructured tip, the sensitivity is increased to identify individual molecules because of the high aspect ratio structure. Various detection methods, such as electrochemistry, fluorescence microcopy, and Raman spectroscopy, have been attempted to enhance the sensitivity and the specificity. Due to the confined path of electrons, electrochemical measurement using a nanotip enables the detection of single molecules. When an electric field is combined with capillary action and fluid flow, target molecules can be effectively concentrated onto a nanotip surface for detection. To enhance the concentration efficacy, a dendritic nanotip rather than a single tip could be used to detect target analytes, such as nanoparticles, cells, and DNA. However, reproducible fabrication with relation to specific detection remains a challenge due to the instability of a manufacturing method, resulting in inconsistent shape. In this paper, nanostructured biosensors are reviewed with our experimental results using dendritic nanotips for sequence specific detection of DNA. By the aid of the Six Sigma approach, the fabrication yield of dendritic nanotips increases from 20.0% to 86.6%. Using the nanotips, DNA is concentrated and detected in a sequence specific way with the detection limit equivalent to 1000 CFU/mL. The pros and cons of a nanotip biosensor are evaluated in conjunction with future prospects.

  3. Nanostructured Tip-Shaped Biosensors: Application of Six Sigma Approach for Enhanced Manufacturing

    PubMed Central

    Kahng, Seong-Joong; Kim, Jong-Hoon; Chung, Jae-Hyun

    2016-01-01

    Nanostructured tip-shaped biosensors have drawn attention for biomolecule detection as they are promising for highly sensitive and specific detection of a target analyte. Using a nanostructured tip, the sensitivity is increased to identify individual molecules because of the high aspect ratio structure. Various detection methods, such as electrochemistry, fluorescence microcopy, and Raman spectroscopy, have been attempted to enhance the sensitivity and the specificity. Due to the confined path of electrons, electrochemical measurement using a nanotip enables the detection of single molecules. When an electric field is combined with capillary action and fluid flow, target molecules can be effectively concentrated onto a nanotip surface for detection. To enhance the concentration efficacy, a dendritic nanotip rather than a single tip could be used to detect target analytes, such as nanoparticles, cells, and DNA. However, reproducible fabrication with relation to specific detection remains a challenge due to the instability of a manufacturing method, resulting in inconsistent shape. In this paper, nanostructured biosensors are reviewed with our experimental results using dendritic nanotips for sequence specific detection of DNA. By the aid of the Six Sigma approach, the fabrication yield of dendritic nanotips increases from 20.0% to 86.6%. Using the nanotips, DNA is concentrated and detected in a sequence specific way with the detection limit equivalent to 1000 CFU/mL. The pros and cons of a nanotip biosensor are evaluated in conjunction with future prospects. PMID:28025540

  4. Reconsideration of macrophage and dendritic cell classification.

    PubMed

    Kadowaki, Takeshi; Shimada, Misato; Inagawa, Hiroyuki; Kohchi, Chie; Hirashima, Mitsuomi; Soma, Gen-Ichiro

    2012-06-01

    It is well known that the activation of innate immune cells, especially antigen-presenting cells such as macrophages and dendritic cells, can ameliorate or exacerbate various diseases, including cancer. Currently, the macrophages and dendritic cells are categorized into several groups by their cell surface and intracellular molecules. However, the detailed classification of the differences between macrophages and dendritic cells has still not been established. Here, we summarized and reviewed the previous studies on the classification of macrophages and dendritic cells. In addition, the previous classification of monocytes, macrophages and dendritic cells is discussed based on our findings of macrophage activation, which has both conventional and plasmacytoid dendritic cell phenotype.

  5. Monogenean anchor morphometry: systematic value, phylogenetic signal, and evolution

    PubMed Central

    Soo, Oi Yoon Michelle; Tan, Wooi Boon; Lim, Lee Hong Susan

    2016-01-01

    Background. Anchors are one of the important attachment appendages for monogenean parasites. Common descent and evolutionary processes have left their mark on anchor morphometry, in the form of patterns of shape and size variation useful for systematic and evolutionary studies. When combined with morphological and molecular data, analysis of anchor morphometry can potentially answer a wide range of biological questions. Materials and Methods. We used data from anchor morphometry, body size and morphology of 13 Ligophorus (Monogenea: Ancyrocephalidae) species infecting two marine mugilid (Teleostei: Mugilidae) fish hosts: Moolgarda buchanani (Bleeker) and Liza subviridis (Valenciennes) from Malaysia. Anchor shape and size data (n = 530) were generated using methods of geometric morphometrics. We used 28S rRNA, 18S rRNA, and ITS1 sequence data to infer a maximum likelihood phylogeny. We discriminated species using principal component and cluster analysis of shape data. Adams’s Kmult was used to detect phylogenetic signal in anchor shape. Phylogeny-correlated size and shape changes were investigated using continuous character mapping and directional statistics, respectively. We assessed morphological constraints in anchor morphometry using phylogenetic regression of anchor shape against body size and anchor size. Anchor morphological integration was studied using partial least squares method. The association between copulatory organ morphology and anchor shape and size in phylomorphospace was used to test the Rohde-Hobbs hypothesis. We created monogeneaGM, a new R package that integrates analyses of monogenean anchor geometric morphometric data with morphological and phylogenetic data. Results. We discriminated 12 of the 13 Ligophorus species using anchor shape data. Significant phylogenetic signal was detected in anchor shape. Thus, we discovered new morphological characters based on anchor shaft shape, the length between the inner root point and the outer root

  6. Dendritic sidebranching with periodic localized perturbations: Directional solidification of pivalic acid--coumarin 152 mixtures

    SciTech Connect

    Williams, L.M.; Muschol, M.; Qian, X.; Losert, W.; Cummins, H.Z. )

    1993-07-01

    We have studied the response of the sidebranches of pivalic acid dendrites, growing by directional solidification, to localized periodic thermal perturbations. The perturbations were generated by a laser beam focused near the tip of a single dendrite growing in a glass capillary, with the pulse duration, repetition rate, and intensity controlled separately. The perturbation dramatically altered the sidebranch structure, producing ordered sidebranches of well-defined wavelength, synchronous with the perturbation, which were strongly correlated on the two sides of the dendrite. The dependencies of the sidebranch amplitude on the frequency of the perturbation and on the distance from the dendrite tip were compared to the predictions of Barber, Barbieri, and Langer [Phys. Rev. A 36, 3340 (1987)] and found to be in qualitative agreement. The value of the selection parameter [sigma] found from these fits to the theory is compared to a value obtained from material parameters also determined in this experiment, and to a value deduced from the initial Mullins-Sekerka instability of the planar crystal-melt interface.

  7. Finding Chemical Anchors in the Kitchen

    ERIC Educational Resources Information Center

    Haim, Liliana

    2005-01-01

    ''The Chemistry Kitchen'', a unit composed of five activities with kitchen elements for elementary students ages 9-11, introduces the children to the skills and chemical working ideas to be used later as anchors for chemical concepts. These activities include kitchen elements, determining the relative mass and so on.

  8. Weighing Anchor in the "Ragged Times"

    ERIC Educational Resources Information Center

    Perry, Tonya B.

    2012-01-01

    In today's middle school classroom, grouping is an essential learning tool that enhances students' ability to collaborate with others and deepen their own thinking. Implementing group work effectively, though, can be a challenge, especially since groups tend to end their work at "ragged" or staggered times. Creating "anchor activities"--respectful…

  9. 76 FR 30301 - Commercial Acquisition; Anchor Tenancy

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-25

    ... Competitiveness Act (CSCA) of 1992. NASA may enter into multi-year anchor tenancy contracts for commercial space... NASA's authority under Section 401 of the Commercial Space Competitiveness Act (CSCA) of 1992 (15 U.S.C... Competitiveness Act, 15 U.S.C. 5806, allows NASA, subject to appropriations, to enter into multi-year...

  10. A Description of the Anchor Test Study.

    ERIC Educational Resources Information Center

    Educational Testing Service, Princeton, NJ.

    The Anchor Test Study is described as to objectives, the need for the study, tests selected for the study, States' participation, renumeration of School Test Coordinator, teacher participation, schedule of activities, reports of test results, pupil personnel data needed, and the tests administered during the restandardization phase and equating…

  11. Anchoring the Panic Disorder Severity Scale

    ERIC Educational Resources Information Center

    Keough, Meghan E.; Porter, Eliora; Kredlow, M. Alexandra; Worthington, John J.; Hoge, Elizabeth A.; Pollack, Mark H.; Shear, M. Katherine; Simon, Naomi M.

    2012-01-01

    The Panic Disorder Severity Scale (PDSS) is a clinician-administered measure of panic disorder symptom severity widely used in clinical research. This investigation sought to provide clinically meaningful anchor points for the PDSS both in terms of clinical severity as measured by the Clinical Global Impression-Severity Scale (CGI-S) and to extend…

  12. Multimodality of Learning Through Anchored Instruction

    ERIC Educational Resources Information Center

    Love, Mary Susan

    2004-01-01

    Multimodality of learning results from the intertextual relationship between multimodal design and other meaning-making modes. Meaning making is becoming more multimodal because language is continually reshaped by new forms of communication media. This article examines anchored instruction from a multimodal perspective. The first section includes…

  13. International Lunar Network (ILN) Anchor Nodes

    NASA Technical Reports Server (NTRS)

    Cohen, Barbara A.

    2009-01-01

    This slide presentation reviews the United States' contribution to the International Lunar Network (ILN) project, the Anchor Nodes project. The ILN is an initiative of 9 national space agencies to establish a set of robotic geophysical monitoring stations on the surface of the Moon. The project is aimed at furthering the understanding of the lunar composition, and interior structure.

  14. 30 CFR 57.7032 - Anchoring.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Drilling and Rotary Jet Piercing Drilling-Underground Only § 57.7032 Anchoring. Columns and the drills mounted on them shall be...

  15. 24 CFR 3285.401 - Anchoring instructions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Anchorage Against Wind § 3285.401... wind by use of anchor assembly type installations or by connecting the home to an alternative... must require the home to be secured against the wind, as described in this section. The installation...

  16. 24 CFR 3285.401 - Anchoring instructions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Anchorage Against Wind § 3285.401... wind by use of anchor assembly type installations or by connecting the home to an alternative... must require the home to be secured against the wind, as described in this section. The installation...

  17. 24 CFR 3285.401 - Anchoring instructions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Anchorage Against Wind § 3285.401... wind by use of anchor assembly type installations or by connecting the home to an alternative... must require the home to be secured against the wind, as described in this section. The installation...

  18. 24 CFR 3285.401 - Anchoring instructions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Anchorage Against Wind § 3285.401... wind by use of anchor assembly type installations or by connecting the home to an alternative... must require the home to be secured against the wind, as described in this section. The installation...

  19. Anchoring the Panic Disorder Severity Scale

    ERIC Educational Resources Information Center

    Keough, Meghan E.; Porter, Eliora; Kredlow, M. Alexandra; Worthington, John J.; Hoge, Elizabeth A.; Pollack, Mark H.; Shear, M. Katherine; Simon, Naomi M.

    2012-01-01

    The Panic Disorder Severity Scale (PDSS) is a clinician-administered measure of panic disorder symptom severity widely used in clinical research. This investigation sought to provide clinically meaningful anchor points for the PDSS both in terms of clinical severity as measured by the Clinical Global Impression-Severity Scale (CGI-S) and to extend…

  20. Finding Chemical Anchors in the Kitchen

    ERIC Educational Resources Information Center

    Haim, Liliana

    2005-01-01

    ''The Chemistry Kitchen'', a unit composed of five activities with kitchen elements for elementary students ages 9-11, introduces the children to the skills and chemical working ideas to be used later as anchors for chemical concepts. These activities include kitchen elements, determining the relative mass and so on.

  1. Weighing Anchor in the "Ragged Times"

    ERIC Educational Resources Information Center

    Perry, Tonya B.

    2012-01-01

    In today's middle school classroom, grouping is an essential learning tool that enhances students' ability to collaborate with others and deepen their own thinking. Implementing group work effectively, though, can be a challenge, especially since groups tend to end their work at "ragged" or staggered times. Creating "anchor activities"--respectful…

  2. At the Tipping Point

    SciTech Connect

    Wiley, H. S.

    2011-02-28

    There comes a time in every field of science when things suddenly change. While it might not be immediately apparent that things are different, a tipping point has occurred. Biology is now at such a point. The reason is the introduction of high-throughput genomics-based technologies. I am not talking about the consequences of the sequencing of the human genome (and every other genome within reach). The change is due to new technologies that generate an enormous amount of data about the molecular composition of cells. These include proteomics, transcriptional profiling by sequencing, and the ability to globally measure microRNAs and post-translational modifications of proteins. These mountains of digital data can be mapped to a common frame of reference: the organism’s genome. With the new high-throughput technologies, we can generate tens of thousands of data points from each sample. Data are now measured in terabytes and the time necessary to analyze data can now require years. Obviously, we can’t wait to interpret the data fully before the next experiment. In fact, we might never be able to even look at all of it, much less understand it. This volume of data requires sophisticated computational and statistical methods for its analysis and is forcing biologists to approach data interpretation as a collaborative venture.

  3. Tipping the scales.

    PubMed

    1998-12-01

    In the US, the October 1998 murder of a physician who performed abortions was an outward manifestation of the insidious battle against legal abortion being waged by radical Christian social conservatives seeking to transform the US democracy into a theocracy. This movement has been documented in a publication entitled, "Tipping the Scales: The Christian Right's Legal Crusade Against Choice" produced as a result of a 4-year investigation conducted by The Center for Reproductive Law and Policy. This publication describes how these fundamentalists have used sophisticated legal, lobbying, and communication strategies to further their goals of challenging the separation of church and state, opposing family planning and sexuality education that is not based solely on abstinence, promoting school prayer, and restricting homosexual rights. The movement has resulted in the introduction of more than 300 anti-abortion bills in states, 50 of which have passed in 23 states. Most Christian fundamentalist groups provide free legal representation to abortion clinic terrorists, and some groups solicit women to bring specious malpractice claims against providers. Sophisticated legal tactics are used by these groups to remove the taint of extremism and mask the danger posed to US constitutional principles being posed by "a well-financed and zealous brand of radical lawyers and their supporters."

  4. Experimental measurements of sidebranching in thermal dendrites under terrestrial-gravity and microgravity conditions.

    PubMed

    Corrigan, D P; Koss, M B; LaCombe, J C; de Jager, K D; Tennenhouse, L A; Glicksman, M E

    1999-12-01

    We perform sidebranch measurements on pure succinonitrile dendrites grown in both microgravity and terrestrial-gravity conditions for a set of supercoolings within the range 0.1-1.0 K. Two distinct types of sidebranch regions, uniform and coarsening, exist, and are characterized by the distance from the tip at which the region began, D(i), and the average spacing of sidebranches within that region, lambda(i). There does not appear to be any significant dependence on either gravity level or supercooling when D(i) or lambda(i) are normalized with respect to the radius of curvature of the tip, R. The apparently constant normalized proportionality factor between D(i), lambda(i), and R, regardless of the relative importance of diffusion and convective heat transport, demonstrates self-similarity between dendrites of different length scales propagating under various heat transfer conditions. However, when the form of the sidebranch envelope is defined by a power law relating the amplitude and relative positions of the sidebranches normalized to the radius of the tip, the form is seen to have significant variations with supercooling between the terrestrial gravity and microgravity growth dendrites. Furthermore, both the amplitude coefficient and exponent from the power-law regressions of the microgravity data are statistically different (95% confidence level) than their terrestrial counterparts.

  5. Dendritic growth in the presence of convection. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Beaghton, Pantelis John

    1988-01-01

    The motion of the freezing front between a dendritic crystal and a supercooled liquid is studied using an interface evolution equation derived from a boundary integral transformation of the transient convective-diffusion equation. A new steady-state theory is introduced that incorporates the effects of convection in dendritic growth. It is shown that in the absence of capillary effects the shape of the crystal-melt interface is a paraboloid of revolution, similar to that found in situations where diffusion is the sole heat transfer mechanism. A relation between the supercooling, the product of the tip velocity and tip radius, and the strength of the flow is derived which reduces to the well-known Ivantsov theory in the absence of convection. A non-linear interface-tracking algorithm is developed and used to study the temporal and spatial evolution of the dendritic interface. The important role of capillarity and convection on the interface dynamics is established and the response of the interface to finite amplitude disturbances is examined for the first time. Tip splitting is identified as the dominant destabilization mechanism in the limit of zero surface tension. Finite surface tension leads to interface stabilization, irrespective of the magnitude and structure of the external perturbations. Finally, convection significantly decreases the magnitude of the freezing velocity.

  6. Dendritic growth in the presence of convection. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Beaghton, Pantelis John

    1988-01-01

    The motion of the freezing front between a dendritic crystal and a supercooled liquid is studied using an interface evolution equation derived from a boundary integral transformation of the transient convective-diffusion equation. A new steady-state theory is introduced that incorporates the effects of convection in dendritic growth. It is shown that in the absence of capillary effects the shape of the crystal-melt interface is a paraboloid of revolution, similar to that found in situations where diffusion is the sole heat transfer mechanism. A relation between the supercooling, the product of the tip velocity and tip radius, and the strength of the flow is derived which reduces to the well-known Ivantsov theory in the absence of convection. A non-linear interface-tracking algorithm is developed and used to study the temporal and spatial evolution of the dendritic interface. The important role of capillarity and convection on the interface dynamics is established and the response of the interface to finite amplitude disturbances is examined for the first time. Tip splitting is identified as the dominant destabilization mechanism in the limit of zero surface tension. Finite surface tension leads to interface stabilization, irrespective of the magnitude and structure of the external perturbations. Finally, convection significantly decreases the magnitude of the freezing velocity.

  7. Experimental measurements of sidebranching in thermal dendrites under terrestrial-gravity and microgravity conditions

    NASA Astrophysics Data System (ADS)

    Corrigan, D. P.; Koss, M. B.; Lacombe, J. C.; de Jager, K. D.; Tennenhouse, L. A.; Glicksman, M. E.

    1999-12-01

    We perform sidebranch measurements on pure succinonitrile dendrites grown in both microgravity and terrestrial-gravity conditions for a set of supercoolings within the range 0.1-1.0 K. Two distinct types of sidebranch regions, uniform and coarsening, exist, and are characterized by the distance from the tip at which the region began, Di, and the average spacing of sidebranches within that region, λi. There does not appear to be any significant dependence on either gravity level or supercooling when Di or λi are normalized with respect to the radius of curvature of the tip, R. The apparently constant normalized proportionality factor between Di, λi, and R, regardless of the relative importance of diffusion and convective heat transport, demonstrates self-similarity between dendrites of different length scales propagating under various heat transfer conditions. However, when the form of the sidebranch envelope is defined by a power law relating the amplitude and relative positions of the sidebranches normalized to the radius of the tip, the form is seen to have significant variations with supercooling between the terrestrial gravity and microgravity growth dendrites. Furthermore, both the amplitude coefficient and exponent from the power-law regressions of the microgravity data are statistically different (95% confidence level) than their terrestrial counterparts.

  8. Influence of Anchoring on Burial Depth of Submarine Pipelines.

    PubMed

    Zhuang, Yuan; Li, Yang; Su, Wei

    2016-01-01

    Since the beginning of the twenty-first century, there has been widespread construction of submarine oil-gas transmission pipelines due to an increase in offshore oil exploration. Vessel anchoring operations are causing more damage to submarine pipelines due to shipping transportation also increasing. Therefore, it is essential that the influence of anchoring on the required burial depth of submarine pipelines is determined. In this paper, mathematical models for ordinary anchoring and emergency anchoring have been established to derive an anchor impact energy equation for each condition. The required effective burial depth for submarine pipelines has then been calculated via an energy absorption equation for the protection layer covering the submarine pipelines. Finally, the results of the model calculation have been verified by accident case analysis, and the impact of the anchoring height, anchoring water depth and the anchor weight on the required burial depth of submarine pipelines has been further analyzed.

  9. 345. Caltrans, Photographer September 20, 1935 "WEST ANCHOR ARM"; DETAIL ...

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

    345. Caltrans, Photographer September 20, 1935 "WEST ANCHOR ARM"; DETAIL VIEW OF CANTILEVER TRUSS WEST ANCHOR ARM UNDER CONSTRUCTION. 7-1023 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  10. Influence of Anchoring on Burial Depth of Submarine Pipelines

    PubMed Central

    Zhuang, Yuan; Li, Yang; Su, Wei

    2016-01-01

    Since the beginning of the twenty-first century, there has been widespread construction of submarine oil-gas transmission pipelines due to an increase in offshore oil exploration. Vessel anchoring operations are causing more damage to submarine pipelines due to shipping transportation also increasing. Therefore, it is essential that the influence of anchoring on the required burial depth of submarine pipelines is determined. In this paper, mathematical models for ordinary anchoring and emergency anchoring have been established to derive an anchor impact energy equation for each condition. The required effective burial depth for submarine pipelines has then been calculated via an energy absorption equation for the protection layer covering the submarine pipelines. Finally, the results of the model calculation have been verified by accident case analysis, and the impact of the anchoring height, anchoring water depth and the anchor weight on the required burial depth of submarine pipelines has been further analyzed. PMID:27166952

  11. 63. ANCHOR WINDLASS ROOM AFT LOOKING FORWARD ON CENTERLINE ...

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

    63. ANCHOR WINDLASS ROOM - AFT LOOKING FORWARD ON CENTERLINE SHOWING LINE REELS, MAIN ANCHOR CHAIN, CHAIN STOPPERS, CAPSTAN AND CONTROLS. - U.S.S. HORNET, Puget Sound Naval Shipyard, Sinclair Inlet, Bremerton, Kitsap County, WA

  12. 9. CABLE ANCHORAGE DETAIL, NORTHWEST ABUTMENT (NOTE MOSSCOVERED CONCRETE ANCHOR ...

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

    9. CABLE ANCHORAGE DETAIL, NORTHWEST ABUTMENT (NOTE MOSS-COVERED CONCRETE ANCHOR LEFT OF ANCHOR BOLTS) - Nisqually Suspension Bridge, Spanning Nisqually River on Service Road, Longmire, Pierce County, WA

  13. Homophilic Dscam interactions control complex dendrite morphogenesis

    PubMed Central

    Hughes, Michael E.; Bortnick, Rachel; Tsubouchi, Asako; Bäumer, Philipp; Kondo, Masahiro; Uemura, Tadashi; Schmucker, Dietmar

    2007-01-01

    Summary The morphogenesis of complex dendritic fields requires highly specific patterning and dendrite-dendrite recognition mechanisms. Alternative splicing of the Drosophila cell surface receptor Dscam results in up to 38,016 different receptor isoforms and in vitro binding studies suggested that sequence variability in immunoglobulin-like ecto-domains determines the specificity of strictly homophilic interactions. We report that diverse Dscam receptors play an important role in controlling cell-intrinsic aspects of dendrite guidance. We examined the function of Dscam during morphogenesis of dendrite arborization neurons (“da” neurons) and found that loss of Dscam in single neurons causes abnormal dendritic fasciculation and a strong increase in self-crossing of dendritic branches of da neurons. Restriction of dendritic fields of neighboring class III neurons appeared intact in Dscam deficient neurons suggesting that dendritic self-avoidance but not hetero-neuronal tiling may depend on Dscam function. Over-expression of the same Dscam isoforms in two da neurons with normally overlapping dendritic fields forced a spatial segregation of the two dendritic fields. Taken together, our results suggest that dendritic branches of all four classes of da neurons use isoform-specific homophilic interactions of Dscam to ensure minimal overlap of dendrites. The large pool of Dscam’s extracellular recognition domains may allow the same ‘core’ repulsion mechanism to be used in every da neuron without interfering with hetero-neuronal interactions. PMID:17481395

  14. Coding and decoding with dendrites.

    PubMed

    Papoutsi, Athanasia; Kastellakis, George; Psarrou, Maria; Anastasakis, Stelios; Poirazi, Panayiota

    2014-02-01

    Since the discovery of complex, voltage dependent mechanisms in the dendrites of multiple neuron types, great effort has been devoted in search of a direct link between dendritic properties and specific neuronal functions. Over the last few years, new experimental techniques have allowed the visualization and probing of dendritic anatomy, plasticity and integrative schemes with unprecedented detail. This vast amount of information has caused a paradigm shift in the study of memory, one of the most important pursuits in Neuroscience, and calls for the development of novel theories and models that will unify the available data according to some basic principles. Traditional models of memory considered neural cells as the fundamental processing units in the brain. Recent studies however are proposing new theories in which memory is not only formed by modifying the synaptic connections between neurons, but also by modifications of intrinsic and anatomical dendritic properties as well as fine tuning of the wiring diagram. In this review paper we present previous studies along with recent findings from our group that support a key role of dendrites in information processing, including the encoding and decoding of new memories, both at the single cell and the network level. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Interpretation of Fracture Toughness and R-Curve Behavior by Direct Observation of Microfracture Process in Ti-Based Dendrite-Containing Amorphous Alloys

    NASA Astrophysics Data System (ADS)

    Jeon, Changwoo; Kim, Choongnyun Paul; Kim, Hyoung Seop; Lee, Sunghak

    2015-04-01

    Fracture properties of Ti-based amorphous alloys containing ductile β dendrites were explained by directly observing microfracture processes. Three Ti-based amorphous alloys were fabricated by adding Ti, Zr, V, Ni, Al, and Be into a Ti-6Al-4V alloy by a vacuum arc melting method. The effective sizes of dendrites varied from 63 to 104 μm, while their volume fractions were almost constant within the range from 74 to 76 pct. The observation of the microfracture of the alloy containing coarse dendrites revealed that a microcrack initiated at the amorphous matrix of the notch tip and propagated along the amorphous matrix. In the alloy containing fine dendrites, the crack propagation was frequently blocked by dendrites, and many deformation bands were formed near or in front of the propagating crack, thereby resulting in a zig-zag fracture path. Crack initiation toughness was almost the same at 35 to 36 MPa√m within error ranges in the three alloys because it was heavily affected by the stress applied to the specimen at the time of crack initiation at the crack tip as well as strength levels of the alloys. According to the R-curve behavior, however, the best overall fracture properties in the alloy containing fine dendrites were explained by mechanisms of blocking of the crack growth and crack blunting and deformation band formation at dendrites.

  16. Lysophosphatidic acid induces osteocyte dendrite outgrowth

    SciTech Connect

    Karagiosis, Sue A.; Karin, Norm J.

    2007-05-25

    A method was developed to measure dendrite formation in bone cells. Lysophosphatidic acid (LPA) was found to stimulate dendrite outgrowth. It is postulated that LPA plays a role in regulating the osteocyte network in vivo.

  17. 62. ANCHOR WINDLASS ROOM AFT LOOKING FORWARD STARBOARD ...

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

    62. ANCHOR WINDLASS ROOM - AFT LOOKING FORWARD - STARBOARD TO PORT SHOWING WINDLASS CONTROLS (HANDWHEELS) MAIN ANCHOR CHAIN, ANCHOR WINDLASS, LINE HEELS, AND LADDERWAY TO SECONDARY CONNING STATION OR PILOT HOUSE. - U.S.S. HORNET, Puget Sound Naval Shipyard, Sinclair Inlet, Bremerton, Kitsap County, WA

  18. Students' Anchoring Predisposition: An Illustration from Spring Training Baseball

    ERIC Educational Resources Information Center

    Mohrweis, Lawrence C.

    2014-01-01

    The anchoring tendency results when decision makers anchor on initial values and then make final assessments that are adjusted insufficiently away from the initial values. The professional literature recognizes that auditors often risk falling into the judgment trap of anchoring and adjusting (Ranzilla et al., 2011). Students may also be unaware…

  19. Gravitational effects in dendritic growth

    NASA Technical Reports Server (NTRS)

    Glicksman, M. E.; Singh, N. B.; Chopra, M.

    1983-01-01

    The theories of diffusion-controlled dendritic crystallization will be reviewed briefly, along with recently published critical experiments on the kinetics and morphology of dendritic growth in pure substances. The influence of the gravitational body force on dendrite growth kinetics will be shown to be highly dependent on the growth orientation with respect to the gravity vector and on the level of the thermal supercooling. In fact, an abrupt transition occurs at a critical supercooling, above which diffusional transport dominates the growth process and below which convective transport dominates. Our most recent work on binary mixtures shows that dilute solute additions influence the crystallization process indirectly, by altering the interfacial stability, rather than by directly affecting the transport mode. Directions for future studies in this field will also be discussed.

  20. Search Tips: MedlinePlus

    MedlinePlus

    ... of this page: https://medlineplus.gov/searchtips.html Search Tips To use the sharing features on this page, please enable JavaScript. How do I search MedlinePlus? The search box appears at the top ...

  1. Girlfriends' Health and Safety Tips

    MedlinePlus

    ... Special Needs: Caregiving Tips Intimate Partner Violence National Domestic Violence Hotline Prevention of Substance Abuse and Mental ... other health care you need. Manage stress from work, children, marriage, commuting, and life! Get enough sleep. ...

  2. Health Tips for Older Adults

    MedlinePlus

    ... clinical feasibility to large multi-center studies Funding Process Tips for applicants; grant review and management resources; and commonly used funding mechanisms, including diversity and small business programs Research Training & Career Development Grant programs for ...

  3. Problem Solving Tips for Teachers.

    ERIC Educational Resources Information Center

    O'Daffer, Phares G.

    1985-01-01

    The focus is on the problem-solving strategy of find a pattern, with a problem explored to illustrate how to use the strategy. Other tips concern classroom climate, checking skills, research, and type of problems. (MNS)

  4. Flu Prevention and Treatment Tips

    MedlinePlus

    Flu Prevention and Treatment Tips Expert Information from Healthcare Professionals Who Specialize in the Care of Older Adults Influenza, or the “flu,” is a contagious respiratory illness. It can cause ...

  5. Tips to Prevent Tick Bites

    EPA Pesticide Factsheets

    Using the right insect repellent and other preventive actions can discourage ticks, mosquitoes, and other biting insects from landing on you. Tips include avoiding tick habitats and minimizing exposed skin.

  6. Spinal Cord Injury Prevention Tips

    MedlinePlus

    ... knee and elbow pads, wrist braces, and gloves. Swimming/diving prevention tips • Do not dive in water ... all rules and warning signs at water parks, swimming pools, and public beaches. • The first time you ...

  7. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    MedlinePlus

    ... ray or ultrasound equipment, a stent, and a balloon-tipped catheter are used. The equipment typically used ... the stent is in the correct position, the balloon is inflated, expanding the stent into place. The ...

  8. Try These Time Management Tips.

    ERIC Educational Resources Information Center

    Bimrose, Jack J.

    1987-01-01

    Offers 12 time management tips for harried school administrators, including using a personal calendar, calling five-minute meetings with secretaries, mail-sorting, delegating or declining certain tasks, controlling visitors, screening phone calls, streamlining meetings, and other ideas. (MLH)

  9. Tips on Writing News Articles

    ERIC Educational Resources Information Center

    White, Shannon

    1975-01-01

    The author offers journalism tips to vocational agriculture teachers involved in public relations coverage through newspaper articles. Specific suggestions cover headlines, leading paragraphs, localization of the story, organization, and format of a news release. (EA)

  10. An Inverse Approach for Elucidating Dendritic Function

    PubMed Central

    Torben-Nielsen, Benjamin; Stiefel, Klaus M.

    2010-01-01

    We outline an inverse approach for investigating dendritic function–structure relationships by optimizing dendritic trees for a priori chosen computational functions. The inverse approach can be applied in two different ways. First, we can use it as a “hypothesis generator” in which we optimize dendrites for a function of general interest. The optimization yields an artificial dendrite that is subsequently compared to real neurons. This comparison potentially allows us to propose hypotheses about the function of real neurons. In this way, we investigated dendrites that optimally perform input-order detection. Second, we can use it as a “function confirmation” by optimizing dendrites for functions hypothesized to be performed by classes of neurons. If the optimized, artificial, dendrites resemble the dendrites of real neurons the artificial dendrites corroborate the hypothesized function of the real neuron. Moreover, properties of the artificial dendrites can lead to predictions about yet unmeasured properties. In this way, we investigated wide-field motion integration performed by the VS cells of the fly visual system. In outlining the inverse approach and two applications, we also elaborate on the nature of dendritic function. We furthermore discuss the role of optimality in assigning functions to dendrites and point out interesting future directions. PMID:21258425

  11. An inverse approach for elucidating dendritic function.

    PubMed

    Torben-Nielsen, Benjamin; Stiefel, Klaus M

    2010-01-01

    We outline an inverse approach for investigating dendritic function-structure relationships by optimizing dendritic trees for a priori chosen computational functions. The inverse approach can be applied in two different ways. First, we can use it as a "hypothesis generator" in which we optimize dendrites for a function of general interest. The optimization yields an artificial dendrite that is subsequently compared to real neurons. This comparison potentially allows us to propose hypotheses about the function of real neurons. In this way, we investigated dendrites that optimally perform input-order detection. Second, we can use it as a "function confirmation" by optimizing dendrites for functions hypothesized to be performed by classes of neurons. If the optimized, artificial, dendrites resemble the dendrites of real neurons the artificial dendrites corroborate the hypothesized function of the real neuron. Moreover, properties of the artificial dendrites can lead to predictions about yet unmeasured properties. In this way, we investigated wide-field motion integration performed by the VS cells of the fly visual system. In outlining the inverse approach and two applications, we also elaborate on the nature of dendritic function. We furthermore discuss the role of optimality in assigning functions to dendrites and point out interesting future directions.

  12. The Equiaxed Dendritic Solidification Experiment (EDSE)

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The Equiaxed Dendritic Solidification Experiment (EDSE) is a material sciences investigation under the Formation of Microstructures/pattern formation discipline. The objective is to study the microstructural evolution of and thermal interactions between several equiaxed crystals growing dendritically in a supercooled melt of a pure and transparent substance under diffusion controlled conditions. Dendrite irritator control for the EDSE in the Microgravity Development Lab (MDL).

  13. Large-scale organization of ribosomal DNA chromatin is regulated by Tip5.

    PubMed

    Zillner, Karina; Filarsky, Michael; Rachow, Katrin; Weinberger, Michael; Längst, Gernot; Németh, Attila

    2013-05-01

    The DNase I accessibility and chromatin organization of genes within the nucleus do correlate to their transcriptional activity. Here, we show that both serum starvation and overexpression of Tip5, a key regulator of ribosomal RNA gene (rDNA) repression, dictate DNase I accessibility, facilitate the association of rDNA with the nuclear matrix and thus regulate large-scale rDNA chromatin organization. Tip5 contains four AT-hooks and a TAM (Tip5/ARBP/MBD) domain, which were proposed to bind matrix-attachment regions (MARs) of the genome. Remarkably, the TAM domain of Tip5 functions as nucleolar localization and nuclear matrix targeting module, whereas AT-hooks do not mediate association with the nuclear matrix, but they are required for nucleolar targeting. These findings suggest a dual role for Tip5's AT-hooks and TAM domain, targeting the nucleolus and anchoring to the nuclear matrix, and suggest a function for Tip5 in the regulation of higher-order rDNA chromatin structure.

  14. Large-scale organization of ribosomal DNA chromatin is regulated by Tip5

    PubMed Central

    Zillner, Karina; Filarsky, Michael; Rachow, Katrin; Weinberger, Michael; Längst, Gernot; Németh, Attila

    2013-01-01

    The DNase I accessibility and chromatin organization of genes within the nucleus do correlate to their transcriptional activity. Here, we show that both serum starvation and overexpression of Tip5, a key regulator of ribosomal RNA gene (rDNA) repression, dictate DNase I accessibility, facilitate the association of rDNA with the nuclear matrix and thus regulate large-scale rDNA chromatin organization. Tip5 contains four AT-hooks and a TAM (Tip5/ARBP/MBD) domain, which were proposed to bind matrix-attachment regions (MARs) of the genome. Remarkably, the TAM domain of Tip5 functions as nucleolar localization and nuclear matrix targeting module, whereas AT-hooks do not mediate association with the nuclear matrix, but they are required for nucleolar targeting. These findings suggest a dual role for Tip5’s AT-hooks and TAM domain, targeting the nucleolus and anchoring to the nuclear matrix, and suggest a function for Tip5 in the regulation of higher-order rDNA chromatin structure. PMID:23580549

  15. Spastin, atlastin, and ER relocalization are involved in axon but not dendrite regeneration

    PubMed Central

    Rao, Kavitha; Stone, Michelle C.; Weiner, Alexis T.; Gheres, Kyle W.; Zhou, Chaoming; Deitcher, David L.; Levitan, Edwin S.; Rolls, Melissa M.

    2016-01-01

    Mutations in >50 genes, including spastin and atlastin, lead to hereditary spastic paraplegia (HSP). We previously demonstrated that reduction of spastin leads to a deficit in axon regeneration in a Drosophila model. Axon regeneration was similarly impaired in neurons when HSP proteins atlastin, seipin, and spichthyin were reduced. Impaired regeneration was dependent on genetic background and was observed when partial reduction of HSP proteins was combined with expression of dominant-negative microtubule regulators, suggesting that HSP proteins work with microtubules to promote regeneration. Microtubule rearrangements triggered by axon injury were, however, normal in all genotypes. We examined other markers to identify additional changes associated with regeneration. Whereas mitochondria, endosomes, and ribosomes did not exhibit dramatic repatterning during regeneration, the endoplasmic reticulum (ER) was frequently concentrated near the tip of the growing axon. In atlastin RNAi and spastin mutant animals, ER accumulation near single growing axon tips was impaired. ER tip concentration was observed only during axon regeneration and not during dendrite regeneration. In addition, dendrite regeneration was unaffected by reduction of spastin or atlastin. We propose that the HSP proteins spastin and atlastin promote axon regeneration by coordinating concentration of the ER and microtubules at the growing axon tip. PMID:27605706

  16. Growth of tertiary dendritic arms during the transient directional solidification of hypoeutectic Pb-Sb alloys

    NASA Astrophysics Data System (ADS)

    Freitas, Emmanuelle S.; Rosa, Daniel M.; Garcia, Amauri; Spinelli, José E.

    2011-12-01

    Despite the importance of a complete characterization of dendritic patterns in castings, the availability of studies on the development of tertiary dendrite arms is scarce in the literature. In the present study, the tip cooling rate, local solidification time, primary and tertiary dendrite arm spacings have been determined in Pb-Sb alloys castings directionally solidified under unsteady-state heat flow conditions. The alloys compositions experimentally examined are widely used in the as-cast condition for the manufacture of positive and negative grids of lead-acid batteries. The initial growth of tertiary dendritic arms from the secondary branches was found to occur only for a Pb-3.5 wt% Sb alloy at cooling rates in the range 0.4-0.2 K/s, with no evidence of this spacing pattern for Pb-Sb alloys having lower solute content. Tertiary dendritic branches have been observed along the entire casting lengths for alloys of the Pb-Sb hypoeutectic range having compositions higher than 4.0 wt% Sb. It is shown that a power function experimental law with a characteristic -0.55 exponent is able to characterize the tertiary spacing evolution with the solidification cooling rate for alloys compositions ≥4.0 wt% Sb. The only exception was the Pb-3.5 wt% Sb alloy for which λ 3 exhibited significant lower values when compared with the experimental values obtained for the other Pb-Sb alloys for a same solidification cooling rate.

  17. Dendrite-Free Lithium Deposition via Self-Healing Electrostatic Shield Mechanism

    SciTech Connect

    Ding, Fei; Xu, Wu; Graff, Gordon L.; Zhang, Jian; Sushko, Maria L.; Chen, Xilin; Shao, Yuyan; Engelhard, Mark H.; Nie, Zimin; Xiao, Jie; Liu, Xingjiang; Sushko, P. V.; Liu, Jun; Zhang, Jiguang

    2013-02-28

    Lithium metal batteries are called the “holy grail” of energy storage systems. However, lithium dendrite growth in these batteries has prevented their practical applications in the last 40 years. Here we show a novel mechanism which can fundamentally change the dendritic morphology of lithium deposition. A low concentration of the second cations (including ions of cesium, rubidium, potassium, and strontium) exhibits an effective reduction potential lower than the standard reduction potential of lithium ions when the chemical activities of these second cations are much lower than that of lithium ions. During lithium deposition, these second cations will form a self-healing electrostatic shield around the initial tip of lithium whenever it is formed. This shield will repel the incoming lithium ions and force them to deposit in the smoother region of the anode so a dendrite-free film is obtained. This mechanism is effective on dendrite prevention in both lithium metal and lithium ion batteries. They may also prevent dendrite growth in other metal batteries and have transformational impact on the smooth deposition in general electrodeposition processes.

  18. Composite materials formed with anchored nanostructures

    DOEpatents

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2015-03-10

    A method of forming nano-structure composite materials that have a binder material and a nanostructure fiber material is described. A precursor material may be formed using a mixture of at least one metal powder and anchored nanostructure materials. The metal powder mixture may be (a) Ni powder and (b) NiAl powder. The anchored nanostructure materials may comprise (i) NiAl powder as a support material and (ii) carbon nanotubes attached to nanoparticles adjacent to a surface of the support material. The process of forming nano-structure composite materials typically involves sintering the mixture under vacuum in a die. When Ni and NiAl are used in the metal powder mixture Ni.sub.3Al may form as the binder material after sintering. The mixture is sintered until it consolidates to form the nano-structure composite material.

  19. Electrochromic mirror using viologen-anchored nanoparticles

    SciTech Connect

    Kim, Han Na; Cho, Seong M.; Ah, Chil Seong; Song, Juhee; Ryu, Hojun; Kim, Yong Hae

    2016-10-15

    Highlights: • Three types of ECM device were fabricated using viologen-anchored ECDs. • The devices were investigated according to their optical structures. • The anti-reflection material affects the reflectance and the coloration efficiency. • The device design of ECMs is a crucial factor for clear reflected images. - Abstract: Electrochromic mirrors (ECMs) that are used in automobile mirrors need to have high reflectance, a high contrast ratio, and a clear image. In particular, it is critical that distortions of clear images are minimized for safety. Therefore, an ECM is fabricated using viologen-anchored nanoparticles and a magnesium fluoride (MgF{sub 2}) layer with an anti-reflection function. The ECM has approximately 30.42% in the reflectance dynamic range and 125 cm{sup 2}/C high coloration efficiency.

  20. Dendritic Growth Morphologies in Al-Zn Alloys—Part II: Phase-Field Computations

    NASA Astrophysics Data System (ADS)

    Dantzig, J. A.; Di Napoli, Paolo; Friedli, J.; Rappaz, M.

    2013-12-01

    In Part I of this article, the role of the Zn content in the development of solidification microstructures in Al-Zn alloys was investigated experimentally using X-ray tomographic microscopy. The transition region between dendrites found at low Zn content and dendrites found at high Zn content was characterized by textured seaweed-type structures. This Dendrite Orientation Transition (DOT) was explained by the effect of the Zn content on the weak anisotropy of the solid-liquid interfacial energy of Al. In order to further support this interpretation and to elucidate the growth mechanisms of the complex structures that form in the DOT region, a detailed phase-field study exploring anisotropy parameters' space is presented in this paper. For equiaxed growth, our results essentially recapitulate those of Haxhimali et al.[1] in simulations for pure materials. We find distinct regions of the parameter space associated with and dendrites, separated by a region where hyperbranched dendrites are observed. In simulations of directional solidification, we find similar behavior at the extrema, but in this case, the anisotropy parameters corresponding to the hyperbranched region produce textured seaweeds. As noted in the experimental work reported in Part I, these structures are actually dendrites that prefer to grow misaligned with respect to the thermal gradient direction. We also show that in this region, the dendrites grow with a blunted tip that oscillates and splits, resulting in an oriented trunk that continuously emits side branches in other directions. We conclude by making a correlation between the alloy composition and surface energy anisotropy parameters.

  1. International Lunar Network (ILN) Anchor Nodes

    NASA Technical Reports Server (NTRS)

    Cohen, Barbara A.

    2008-01-01

    This slide presentation reviews what we know about the interior and surface of the moon and the need to establish a robotic set of geophysical monitoring stations on the surface of the Moon for the purpose of providing significant scientific value to the exploration of the Moon. The ILN Anchor Nodes will provide the backbone of the network in a way that accomplishes new science and allows other nodes to be flexible contributors to the network.

  2. Anchoring in a novel bimanual coordination pattern.

    PubMed

    Maslovat, Dana; Lam, Melanie Y; Brunke, Kirstin M; Chua, Romeo; Franks, Ian M

    2009-02-01

    Anchoring in cyclical movements has been defined as regions of reduced spatial or temporal variability [Beek, P. J. (1989). Juggling dynamics. PhD thesis. Amsterdam: Free University Press] that are typically found at movement reversal points. For in-phase and anti-phase movements, synchronizing reversal points with a metronome pulse has resulted in decreased anchor point variability and increased pattern stability [Byblow, W. D., Carson, R. G., & Goodman, D. (1994). Expressions of asymmetries and anchoring in bimanual coordination. Human Movement Science, 13, 3-28; Fink, P. W., Foo, P., Jirsa, V. K., & Kelso, J. A. S. (2000). Local and global stabilization of coordination by sensory information. Experimental Brain Research, 134, 9-20]. The present experiment examined anchoring during acquisition, retention, and transfer of a 90 degrees phase-offset continuous bimanual coordination pattern (whereby the right limb lags the left limb by one quarter cycle), involving horizontal flexion about the elbow. Three metronome synchronization strategies were imposed: participants either synchronized maximal flexion of the right arm (i.e., single metronome), both flexion and extension of the right arm (i.e., double metronome within-limb), or flexion of each arm (i.e., double metronome between-limb) to an auditory metronome. In contrast to simpler in-phase and anti-phase movements, synchronization of additional reversal points to the metronome did not reduce reversal point variability or increase pattern stability. Furthermore, practicing under different metronome synchronization strategies did not appear to have a significant effect on the rate of acquisition of the pattern.

  3. Resisting anchoring effects: The roles of metric and mapping knowledge.

    PubMed

    Smith, Andrew R; Windschitl, Paul D

    2015-10-01

    The biasing influence of anchors on numerical estimates is well established, but the relationship between knowledge level and the susceptibility to anchoring effects is less clear. In two studies, we addressed the potential mitigating effects of having knowledge in a domain on vulnerability to anchoring effects in that domain. Of critical interest was a distinction between two forms of knowledge-metric and mapping knowledge. In Study 1, participants who had studied question-relevant information-that is, high-knowledge participants-were less influenced by anchors than were participants who had studied irrelevant information. The results from knowledge measures suggested that the reduction in anchoring was tied to increases in metric rather than mapping knowledge. In Study 2, participants studied information specifically designed to influence different types of knowledge. As we predicted, increases in metric knowledge-and not mapping knowledge-led to reduced anchoring effects. Implications for debiasing anchoring effects are discussed.

  4. Anchoring-driven spontaneous rotations in active gel droplets.

    PubMed

    Fialho, A R; Blow, M L; Marenduzzo, D

    2017-09-13

    We study the dynamics of an active gel droplet with imposed orientational anchoring (normal or planar) at its surface. We find that if the activity is large enough droplets subject to strong anchoring spontaneously start to rotate, with the sense of rotation randomly selected by fluctuations. Contractile droplets rotate only for planar anchoring and extensile ones only for normal anchoring. This is because such a combination leads to a pair of stable elastic deformations which creates an active torque to power the rotation. Interestingly, under these conditions there is a conflict between the anchoring promoted thermodynamically and that favoured by activity. By tuning activity and anchoring strength, we find a wealth of qualitatively different droplet morphologies and spatiotemporal patterns, encompassing steady rotations, oscillations, and more irregular trajectories. The spontaneous rotations we observe are fundamentally different from previously reported instances of rotating defects in active fluids as they require the presence of strong enough anchoring and entail significant droplet shape deformations.

  5. Intrinsic and extrinsic mechanisms of dendritic morphogenesis.

    PubMed

    Dong, Xintong; Shen, Kang; Bülow, Hannes E

    2015-01-01

    The complex, branched morphology of dendrites is a cardinal feature of neurons and has been used as a criterion for cell type identification since the beginning of neurobiology. Regulated dendritic outgrowth and branching during development form the basis of receptive fields for neurons and are essential for the wiring of the nervous system. The cellular and molecular mechanisms of dendritic morphogenesis have been an intensely studied area. In this review, we summarize the major experimental systems that have contributed to our understandings of dendritic development as well as the intrinsic and extrinsic mechanisms that instruct the neurons to form cell type-specific dendritic arbors.

  6. Regulation of dendrite morphogenesis by extrinsic cues.

    PubMed

    Valnegri, Pamela; Puram, Sidharth V; Bonni, Azad

    2015-07-01

    Dendrites play a central role in the integration and flow of information in the nervous system. The morphogenesis and maturation of dendrites is hence an essential step in the establishment of neuronal connectivity. Recent studies have uncovered crucial functions for extrinsic cues in the development of dendrites. We review the contribution of secreted polypeptide growth factors, contact-mediated proteins, and neuronal activity in distinct phases of dendrite development. We also highlight how extrinsic cues influence local and global intracellular mechanisms of dendrite morphogenesis. Finally, we discuss how these studies have advanced our understanding of neuronal connectivity and have shed light on the pathogenesis of neurodevelopmental disorders.

  7. Bone marrow-derived dendritic cells.

    PubMed

    Roney, Kelly

    2013-01-01

    While much is understood about dendritic cells and their role in the immune system, the study of these cells is critical to gain a more complete understanding of their function. Dendritic cell isolation from mouse body tissues can be difficult and the number of cells isolated small. This protocol describes the growth of large number of dendritic cells from the culture of mouse bone marrow cells. The dendritic cells grown in culture facilitate experiments that may require large number of dendritic cells without great expense or use of large number of mice.

  8. Electropermanent magnetic anchoring for surgery and endoscopy.

    PubMed

    Tugwell, Josef; Brennan, Philip; O'Shea, Conor; O'Donoghue, Kilian; Power, Timothy; O'Shea, Michael; Griffiths, James; Cahill, Ronan; Cantillon-Murphy, Padraig

    2015-03-01

    The use of magnets for anchoring of instrumentation in minimally invasive surgery and endoscopy has become of increased interest in recent years. Permanent magnets have significant advantages over electromagnets for these applications; larger anchoring and retraction force for comparable size and volume without the need for any external power supply. However, permanent magnets represent a potential hazard in the operating field where inadvertent attraction to surgical instrumentation is often undesirable. The current work proposes an interesting hybrid approach which marries the high forces of permanent magnets with the control of electromagnetic technology including the ability to turn the magnet OFF when necessary. This is achieved through the use of an electropermanent magnet, which is designed for surgical retraction across the abdominal and gastric walls. Our electropermanent magnet, which is hand-held and does not require continuous power, is designed with a center lumen which may be used for trocar or needle insertion. The device in this application has been demonstrated successfully in the porcine model where coupling between an intraluminal ring magnet and our electropermanent magnet facilitated guided insertion of an 18 Fr Tuohy needle for guidewire placement. Subsequent investigations have demonstrated the ability to control the coupling distance of the system alleviating shortcomings with current methods of magnetic coupling due to variation in transabdominal wall thicknesses. With further refinement, the magnet may find application in the anchoring of endoscopic and surgical instrumentation for minimally invasive interventions in the gastrointestinal tract.

  9. Short read DNA fragment anchoring algorithm.

    PubMed

    Wang, Wendi; Zhang, Peiheng; Liu, Xinchun

    2009-01-30

    The emerging next-generation sequencing method based on PCR technology boosts genome sequencing speed considerably, the expense is also get decreased. It has been utilized to address a broad range of bioinformatics problems. Limited by reliable output sequence length of next-generation sequencing technologies, we are confined to study gene fragments with 30 - 50 bps in general and it is relatively shorter than traditional gene fragment length. Anchoring gene fragments in long reference sequence is an essential and prerequisite step for further assembly and analysis works. Due to the sheer number of fragments produced by next-generation sequencing technologies and the huge size of reference sequences, anchoring would rapidly becoming a computational bottleneck. We compared algorithm efficiency on BLAT, SOAP and EMBF. The efficiency is defined as the count of total output results divided by time consumed to retrieve them. The data show that our algorithm EMBF have 3 - 4 times efficiency advantage over SOAP, and at least 150 times over BLAT. Moreover, when the reference sequence size is increased, the efficiency of SOAP will get degraded as far as 30%, while EMBF have preferable increasing tendency. In conclusion, we deem that EMBF is more suitable for short fragment anchoring problem where result completeness and accuracy is predominant and the reference sequences are relatively large.

  10. Advanced dendritic web growth development

    NASA Technical Reports Server (NTRS)

    Hopkins, R. H.

    1985-01-01

    A program to develop the technology of the silicon dendritic web ribbon growth process is examined. The effort is being concentrated on the area rate and quality requirements necessary to meet the JPL/DOE goals for terrestrial PV applications. Closed loop web growth system development and stress reduction for high area rate growth is considered.

  11. Turbine blade with contoured chamfered squealer tip

    SciTech Connect

    Lee, Ching-Pang

    2014-12-30

    A squealer tip formed from a pressure side tip wall and a suction side tip wall extending radially outward from a tip of the turbine blade is disclosed. The pressure and suction side tip walls may be positioned along the pressure sidewall and the suction sidewall of the turbine blade, respectively. The pressure side tip wall may include a chamfered leading edge with film cooling holes having exhaust outlets positioned therein. An axially extending tip wall may be formed from at least two outer linear surfaces joined together at an intersection forming a concave axially extending tip wall. The axially extending tip wall may include a convex inner surface forming a radially outer end to an inner cavity forming a cooling system. The cooling system may include one or more film cooling holes in the axially extending tip wall proximate to the suction sidewall, which promotes increased cooling at the pressure and suction sidewalls.

  12. Complications of bioabsorbable suture anchors in the shoulder.

    PubMed

    Dhawan, Aman; Ghodadra, Neil; Karas, Vasili; Salata, Michael J; Cole, Brian J

    2012-06-01

    The development of the suture anchor has played a pivotal role in the transition from open to arthroscopic techniques of the shoulder. Various suture anchors have been manufactured that help facilitate the ability to create a soft tissue to bone repair. Because of reported complications of loosening, migration, and chondral injury with metallic anchors, bioabsorbable anchors have become increasingly used among orthopaedic surgeons. In this review, the authors sought to evaluate complications associated with bioabsorbable anchors in or about the shoulder and understand these in the context of the total number of bioabsorbable anchors placed. In 2008, 10 bioabsorbable anchor-related complications were reported to the US Food and Drug Administration. The reported literature complications of bioabsorbable anchors implanted about the shoulder include glenoid osteolysis, synovitis, and chondrolysis. These potential complications should be kept in mind when forming a differential diagnosis in a patient in whom a bioabsorbable anchor has been previously used. These literature reports, which amount to but a fraction of the total bioabsorbable anchors implanted in the shoulder on a yearly basis, underscore the relative safety and successful clinical results with use of bioabsorbable suture anchors. Product development continues with newer composites such as PEEK (polyetheretherketone) and calcium ceramics (tricalcium phosphate) in an effort to hypothetically create a mechanically stable construct with and improve biocompatibility of the implant. Bioabsorbable anchors remain a safe, reproducible, and consistent implant to secure soft tissue to bone in and about the shoulder. Meticulous insertion technique must be followed in using bioabsorbable anchors and may obviate many of the reported complications found in the literature. The purpose of this review is to provide an overview of the existing literature as it relates to the rare complications seen with use of bioabsorbable

  13. Molecular and cellular mechanisms of dendritic morphogenesis

    PubMed Central

    Gao, Fen-Biao

    2008-01-01

    Summary Dendrites exhibit unique cell-type specific branching patterns and targeting specificity that are critically important for neuronal function and connectivity. Recent evidence indicates that highly complex transcriptional regulatory networks dictate various aspects of dendritic outgrowth, branching, and routing. In addition to other intrinsic molecular pathways such as membrane protein trafficking, interactions between neighboring dendritic branches also contribute to the final specification of dendritic morphology. Nonredundant coverage by dendrites of same type of neurons, known as tiling, requires the actions of the Tricornered/Furry (Sax-1/Sax-2) signaling pathway. However, the dendrites of a neuron do not cross over each other, a process called self-avoidance that is mediated by Down’s syndrome cell adhesion molecule (Dscam). Those exciting findings have enhanced significantly our understanding of dendritic morphogenesis and revealed the magnitude of complexity in the underlying molecular regulatory networks. PMID:17933513

  14. Robotic Ankle for Omnidirectional Rock Anchors

    NASA Technical Reports Server (NTRS)

    Parness, Aaron; Frost, Matthew; Thatte, Nitish

    2013-01-01

    Future robotic exploration of near-Earth asteroids and the vertical and inverted rock walls of lava caves and cliff faces on Mars and other planetary bodies would require a method of gripping their rocky surfaces to allow mobility without gravitational assistance. In order to successfully navigate this terrain and drill for samples, the grippers must be able to produce anchoring forces in excess of 100 N. Additionally, the grippers must be able to support the inertial forces of a moving robot, as well gravitational forces for demonstrations on Earth. One possible solution would be to use microspine arrays to anchor to rock surfaces and provide the necessary load-bearing abilities for robotic exploration of asteroids. Microspine arrays comprise dozens of small steel hooks supported on individual suspensions. When these arrays are dragged along a rock surface, the steel hooks engage with asperities and holes on the surface. The suspensions allow for individual hooks to engage with asperities while the remaining hooks continue to drag along the surface. This ensures that the maximum possible number of hooks engage with the surface, thereby increasing the load-bearing abilities of the gripper. Using the microspine array grippers described above as the end-effectors of a robot would allow it to traverse terrain previously unreachable by traditional wheeled robots. Furthermore, microspine-gripping robots that can perch on cliffs or rocky walls could enable a new class of persistent surveillance devices for military applications. In order to interface these microspine grippers with a legged robot, an ankle is needed that can robotically actuate the gripper, as well as allow it to conform to the large-scale irregularities in the rock. The anchor serves three main purposes: deploy and release the anchor, conform to roughness or misalignment with the surface, and cancel out any moments about the anchor that could cause unintentional detachment. The ankle design contains a

  15. Predictions of the Hunt-Lu array model compared with measurements for the growth undercooling of Al{sub 3}Fe dendrites in Al-Fe alloys

    SciTech Connect

    Liang, D.; Jones, H.

    1997-10-01

    Earlier contributions by the authors reported the first measurements of growth temperature as a function of growth velocity V and alloy concentration C{sub 0} for a dendritic intermetallic phase (Al{sub 3}Fe, in Al-rich Al-Fe alloys). Comparison with predictions of the model of Kurz, Giovanola and Trivedi (KGT model) of dendrite growth of a needle gave predicted {Delta}T a factor between 1.1 and 2.5 above the measured values. A subsequent paper presented evidence that the Al{sub 3}Fe dendrite tips were indeed needle-like under the conditions studied, as distinct from the plate-like morphology that develops behind the dendrite tips. The KGT model predicts T{sub G} and {Delta}T on the basis that marginal stability determines the operating condition at the dendrite tip. The present purpose is to compare the measurements with predictions of the more recently developed array model of Hunt and Lu.

  16. Anatomy Of A Better Tip

    NASA Astrophysics Data System (ADS)

    Webster, Wilton W.

    1989-08-01

    We have developed a unique electrode catheter which combines a deflectable tip with a high torque shaft. The control handle is at the proximal end of the catheter. The control handle and the electrical connector which extends out the back of it are symmetrical about the catheter axis for optimum control. The tip deflects to the desired curve when a piston at the distal end of the handle is pushed forward by a thumb ring, and straightens again when the piston is pulled back. I will talk today about how we have developed this catheter. Although this may seem far afield from an SPIE subject, remember that any catheter used for transferring electrical or laser energy inside the body must have some rather unique properties. The tip or delivery end of the catheter must be placed and controlled correctly from outside the body two or three feet proximal from the tip. This catheter is used by cardiac electrophysiologists to study the electrical conduction system of the heart. During the past ten years the science of electrophysiology (EP) has seen major advances. But the tools of the trade, the catheters for performing the studies, have not significantly improved. Our deflectable tip catheter is indeed a significant advancement.

  17. Evidence that dendritic mitochondria negatively regulate dendritic branching in pyramidal neurons in the neocortex.

    PubMed

    Kimura, Toshiya; Murakami, Fujio

    2014-05-14

    The precise branching patterns of dendritic arbors have a profound impact on information processing in individual neurons and the brain. These patterns are established by positive and negative regulation of the dendritic branching. Although the mechanisms for positive regulation have been extensively investigated, little is known about those for negative regulation. Here, we present evidence that mitochondria located in developing dendrites are involved in the negative regulation of dendritic branching. We visualized mitochondria in pyramidal neurons of the mouse neocortex during dendritic morphogenesis using in utero electroporation of a mitochondria-targeted fluorescent construct. We altered the mitochondrial distribution in vivo by overexpressing Mfn1, a mitochondrial shaping protein, or the Miro-binding domain of TRAK2 (TRAK2-MBD), a truncated form of a motor-adaptor protein. We found that dendritic mitochondria were preferentially targeted to the proximal portion of dendrites only during dendritic morphogenesis. Overexpression of Mfn1 or TRAK2-MBD depleted mitochondria from the dendrites, an effect that was accompanied by increased branching of the proximal portion of the dendrites. This dendritic abnormality cannot be accounted for by changes in the distribution of membrane trafficking organelles since the overexpression of Mfn1 did not alter the distributions of the endoplasmic reticulum, Golgi, or endosomes. Additionally, neither did these constructs impair neuronal viability or mitochondrial function. Therefore, our results suggest that dendritic mitochondria play a critical role in the establishment of the precise branching pattern of dendritic arbors by negatively affecting dendritic branching.

  18. Cancer targeting potential of some ligand-anchored poly(propylene imine) dendrimers: a comparison.

    PubMed

    Kesharwani, Prashant; Tekade, Rakesh K; Gajbhiye, Virendra; Jain, Keerti; Jain, Narendra K

    2011-06-01

    The present investigation was aimed at developing and comparing the cancer-targeting potential of ligand-anchored dendrimers. Folate-, dextran-, and galactose-anchored poly(propylene imine) dendrimers were synthesized and characterized. Dendritic formulations were evaluated for ex vivo cytotoxicity on HeLa and SiHa cell lines. Flow cytometry studies were performed on the HeLa cell line. An ex vivo MTT assay on HeLa cells indicated IC(50) values of 0.05, 0.2, 0.8, and 0.08 μM for folate, dextran, and galactose formulations, and for free paclitaxel (PTX), respectively. An analogous observation was carried out in SiHa cells, where IC(50) values of 0.6, 0.8, 10, and 6 μM were observed by folate, dextran, and galactose formulations, and free PTX, respectively. The outcome of the MTT assay and flow cytometry suggested the order of targeting potential of various ligands under investigation as folate > dextran > galactose. The outcome is deemed to be of scientific value and is believed to assist drug delivery scientists during selection of targeting ligands. The cancer targeting potential of folate, dextran and galactose functionalized polypropyleneimine (PPI) dendrimers was studied by this group of investigators, reporting the order of targeting potential as folate > dextran > galactose. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Multivalent anchored and crosslinked hyperbranched polyglycerol monolayers as antifouling coating for titanium oxide surfaces.

    PubMed

    Wei, Qiang; Krysiak, Stefanie; Achazi, Katharina; Becherer, Tobias; Noeske, Paul-Ludwig Michael; Paulus, Florian; Liebe, Hendrik; Grunwald, Ingo; Dernedde, Jens; Hartwig, Andreas; Hugel, Thorsten; Haag, Rainer

    2014-10-01

    A set of new catecholic monolayer coatings was developed to improve the antifouling performance of TiO2 surfaces. To solve the problem of the weak charge-transfer interaction between a single catechol anchor and TiO2, multiple catechol groups were combined with hyperbranched polyglycerol (hPG) which is a distinct dendritic scaffold that exposes its multivalent anchor groups on the surface. Thus, multivalent catecholic hPGs can be easily prepared for surface modification. The immobilization of the compounds was monitored by quartz crystal microbalance with dissipation monitoring. Surface properties of the coatings were analyzed by water contact angle, X-ray photoelectron spectroscopy, and atomic force microscopy. The antifouling ability and stability were investigated by protein adsorption and cell adhesion. By increasing the number of catechol groups on the hPG scaffold, the stability and surface coverage could be significantly enhanced. Moreover, the inner-layer crosslinking of the coatings by grafting and initiating vinyl groups clearly improved their long-term stability. As a result, hPG with a catecholic functional degree of 10% (hPG-Cat10) and hPG with both catecholic and vinylic functional degree of 5% (hPG-Cat5-V5) were identified as the best catecholic hPGs to prepare bioinert and stable monolayer coatings on TiO2.

  20. Anomalous Surface Distribution of Glycosyl Phosphatidyl Inositol–anchored Proteins in Neurons Lacking Acid Sphingomyelinase

    PubMed Central

    Galvan, Cristian; Camoletto, Paola G.; Cristofani, Flavio; Van Veldhoven, Paul P.

    2008-01-01

    Acid sphingomyelinase (ASM) converts sphingomyelin (SM) into ceramide. Mutations in the ASM gene cause the mental retardation syndrome Niemann Pick type A (NPA), characterized as a lysosomal disorder because of the SM accumulation in these organelles. We here report that neurons from mice lacking ASM (ASMKO) present increased plasma membrane SM levels evident in detergent-resistant membranes. Paralleling this lipidic alteration, GPI-anchored proteins show an aberrant distribution in both axons and dendrites instead of the axonal enrichment observed in neurons from wild-type mice. Trafficking analysis suggests that this is due to defective internalization from dendrites. Increasing the SM content in wild-type neurons mimics these defects, whereas SM reduction in ASMKO neurons prevents their occurrence. Moreover, expression of active RhoA, which membrane attachment is affected by SM accumulation, rescues internalization rates in ASMKO neurons. These data unveil an unexpected role for ASM in neuronal plasma membrane organization and trafficking providing insight on the molecular mechanisms involved. They also suggest that deficiencies in such processes could be key pathological events in NPA disease. PMID:18032586

  1. Management of thumb tip injuries.

    PubMed

    Germann, Günter; Sauerbier, Michael; Rudolf, Klaus D; Hrabowski, Manuel

    2015-03-01

    The management of thumb tip injuries has undergone great changes in recent years. The traditional armamentarium of flaps has been expanded and replaced by a wide variety of flaps with more versatility and less donor side morbidity. Parallel to the development of new flaps, the conservative treatment of thumb tip injuries with semi-occlusive dressing has gained ground in the treatment of these injuries. Although tedious and time-consuming, and requiring intensive communication with the patient to explain the look and occasionally fetid smell of the wound, this technique yields excellent results with respect to restoring contour and sensibility in pulp injuries. The article gives an update on the current options for treating thumb tip injuries including the most commonly applied flaps. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  2. Nanobits: customizable scanning probe tips

    NASA Astrophysics Data System (ADS)

    Rajendra Kumar, R. T.; Hassan, S. U.; Sardan Sukas, O.; Eichhorn, V.; Krohs, F.; Fatikow, S.; Boggild, P.

    2009-09-01

    We present here a proof-of-principle study of scanning probe tips defined by planar nanolithography and integrated with AFM probes using nanomanipulation. The so-called 'nanobits' are 2-4 µm long and 120-150 nm thin flakes of Si3N4 or SiO2, fabricated by electron beam lithography and standard silicon processing. Using a microgripper they were detached from an array and fixed to a standard pyramidal AFM probe or alternatively inserted into a tipless cantilever equipped with a narrow slit. The nanobit-enhanced probes were used for imaging of deep trenches, without visible deformation, wear or dislocation of the tips of the nanobit after several scans. This approach allows an unprecedented freedom in adapting the shape and size of scanning probe tips to the surface topology or to the specific application.

  3. Nanobits: customizable scanning probe tips.

    PubMed

    Rajendra Kumar, R T; Hassan, S U; Sardan Sukas, O; Eichhorn, V; Krohs, F; Fatikow, S; Boggild, P

    2009-09-30

    We present here a proof-of-principle study of scanning probe tips defined by planar nanolithography and integrated with AFM probes using nanomanipulation. The so-called 'nanobits' are 2-4 microm long and 120-150 nm thin flakes of Si(3)N(4) or SiO(2), fabricated by electron beam lithography and standard silicon processing. Using a microgripper they were detached from an array and fixed to a standard pyramidal AFM probe or alternatively inserted into a tipless cantilever equipped with a narrow slit. The nanobit-enhanced probes were used for imaging of deep trenches, without visible deformation, wear or dislocation of the tips of the nanobit after several scans. This approach allows an unprecedented freedom in adapting the shape and size of scanning probe tips to the surface topology or to the specific application.

  4. Histologic and morphologic evaluation of explanted bone anchors from bone-anchored hearing aids.

    PubMed

    Mlynski, Robert; Goldberg, Eva; Ebmeyer, Joerg; Scheich, Matthias; Gattenlöhner, Stefan; Schwager, Konrad; Hagen, Rudolf; Shehata-Dieler, Wafaa

    2009-05-01

    Bone-anchored hearing aids are a standard option in rehabilitation of patients with conductive or mixed hearing loss, and also CROS fitting. However, the skin-penetrating bone anchor repeatedly gives reason for discussion about the risk of infection of surrounding tissues as a major cause of malfunction. In the present study, explanted bone anchors with surrounding bone and soft tissue were examined and compared with the morphology of lost implants. The anchors originated from five patients. Two needed explantation due to deafness with the need of cochlea implantation. A third patient underwent explantation due to meningeal irritation by the bone anchor. Another patient lost the implant due to mechanical stress shortly after implantation. The last implant was lost in a child without apparent reason. All implants were clinically free of infection and had been stable for a median implantation period of 12 months. During the explantation procedure, the fixtures were recovered together with the attached soft tissue and bone. The specimens were examined by light microscopy or scanning electron microscopy (SEM). Sectioning for light microscopy was performed with a diamond-coated saw microtome. Histopathologic examination of the surrounding skin and subcutaneous soft tissue showed slight inflammation in one case only. The bone was regularly vital, presenting no signs of inflammation. The threads of the fixtures were filled with bone, with particularly strong attachment to the flank of traction. The SEM investigation exposed the ultrastructural interaction of bone with the implant surface. Filiform- and podocyte-like processes of osteocytes attach to the implant; lost implants did not reflect these features. Implant integration involves both osseointegration as well as soft tissue integration. Titanium oxide as the active implant surface promotes this integration even in unstable implants. The morphologic analysis exposed structural areas of the implant with weak bone

  5. Tipping Points in Texas Rivers

    NASA Astrophysics Data System (ADS)

    Phillips, Jonathan

    2016-04-01

    Anticipating geomorphic tipping points requires that we learn from the past. Major geomorphic changes in coastal plain rivers of Texas resulting in river metamorphosis or regime shifts were identified, and the major driving factors determined. Nine fluvial tipping points were identified from contemporary observations, historical records, and Quaternary reconstructions. Two of the tipping points (between general aggrading and degrading valley states) are associated with reversals in a fundamental system control (sea-level). One (stable or aggrading vs. degrading channels) is associated with an abrupt change in sediment supply due to dam construction, and two others (changes from meandering to anastomosing channel patterns, and different anastomosis styles) are similarly related to changes in sediment supply and/or transport capacity, but with additional elements of historical contingency. Three tipping points are related to avulsions. One, from a regime dominated to reoccupation of former channels to one dominated by progradation into flood basins, is driven by progressive long term filling of incised valleys. Another, nodal avulsions, are driven by disturbances associated with tectonics or listric faults. The third, avulsions and related valley metamorphosis in unfilled incised valleys, is due to fundamental dynamical instabilities within the fluvial system. This synthesis and analysis suggests that geomorphic tipping points are sometimes associated with general extrinsic or intrinsic (to the fluvial system) environmental change, independent of any disturbances or instabilities. Others are associated with natural (e.g., tectonic) or human (dams) disturbances, and still others with intrinsic geomorphic instabilities. This suggests that future tipping points will be equally diverse with respect to their drivers.

  6. [Technical Tips for Spinal Anesthesia].

    PubMed

    Shima, Takeshi

    2015-09-01

    Spinal anesthesia is a standard technique for all anesthesiologists and surgeons. This review deals with basic knowledge and tips for spinal anesthesia in an empirical manner. It is important to understand practical knowledge about specific character of each local anesthetic, spread patterns of the anesthetics in the subarachnoid space and relation between anesthesia level and puncture site. This review also introduces tips for subarachnoid puncture and divided administration method of isobaric local anesthetic solution based on the literature. Anesthesiologists and surgeons have to recognize that it is necessary to take enough time to perform precious and optimal spinal anesthesia.

  7. Research With Scanning Tip Microscopy

    DTIC Science & Technology

    1991-12-31

    08ro P noiwe bae?041Le Research With Scanning Tip Microscopy AFOSR-89-0498 V AUTHOS)i Professor Dror Sarid 7. PFOUImNG 00ANIZATION NAMEIS) AND...forces and (b) surfaces. UNCLASS UNCLASS UNCLASS UL FINAL REPORT TO THE AFOSR ൱-, to J4ti. r Aat io Research in Scanning Tip Microscopy Dror Sarid Dtst...microscopy have been used to investigate (a) forces and (b) surfaces. a. Forces 1. Dror Sarid , Douglas lams, Volker Weissenberger, and L. Stephen Bell

  8. Tip-alpha (hp0596 gene product) is a highly immunogenic Helicobacter pylori protein involved in colonization of mouse gastric mucosa.

    PubMed

    Godlewska, Renata; Pawlowski, Marcin; Dzwonek, Artur; Mikula, Michal; Ostrowski, Jerzy; Drela, Nadzieja; Jagusztyn-Krynicka, Elzbieta K

    2008-03-01

    A product of the Helicobacter pylori hp0596 gene (Tip-alpha) is a highly immunogenic homodimeric protein, unique for this bacterium. Cell fractionation experiments indicate that Tip-alpha is anchored to the inner membrane. In contrast, the three-dimensional model of the protein suggests that Tip-alpha is soluble or, at least, largely exposed to the solvent. hp0596 gene knockout resulted in a significant decrease in the level of H. pylori colonization as measured by real-time PCR assay. In addition, the Tip-alpha recombinant protein was determined to stimulate macrophage to produce IL-1alpha and TNF-alpha. Both results imply that Tip-alpha is rather loosely connected to the inner membrane and potentially released during infection.

  9. Detachment of secondary dendrite arm in a directionally solidified Sn-Ni peritectic alloy under deceleration growth condition

    NASA Astrophysics Data System (ADS)

    Peng, Peng; Li, Xinzhong; Li, Jiangong; Su, Yanqing; Guo, Jingjie; Fu, Hengzhi

    2016-06-01

    In order to better understand the detachment mechanism of secondary dendrite arm during peritectic solidification, the detachment of secondary dendrite arm from the primary dendrite arms in directionally solidified Sn-36at.%Ni peritectic alloys is investigated at different deceleration rates. Extensive detachment of secondary dendrite arms from primary stem is observed below peritectic reaction temperature TP. And an analytical model is established to characterize the detachment process in terms of the secondary dendrite arm spacing λ2, the root radius of detached arms and the specific surface area (SV) of dendrites. It is found that the detachment mechanism is caused by not only curvature difference between the tips and roots of secondary branches, but also that between the thicker secondary branches and the thinner ones. Besides, this detachment process is significantly accelerated by the temperature gradient zone melting (TGZM) effect during peritectic solidification. It is demonstrated that the reaction constant (f) which is used to characterize the kinetics of peritectic reaction is crucial for the determination of the detachment process. The value of f not only changes with growth rate but also with solidification time at a given deceleration rate. In conclusion, these findings help the better understanding of the detachment mechanism.

  10. Detachment of secondary dendrite arm in a directionally solidified Sn-Ni peritectic alloy under deceleration growth condition

    PubMed Central

    Peng, Peng; Li, Xinzhong; Li, Jiangong; Su, Yanqing; Guo, Jingjie; Fu, Hengzhi

    2016-01-01

    In order to better understand the detachment mechanism of secondary dendrite arm during peritectic solidification, the detachment of secondary dendrite arm from the primary dendrite arms in directionally solidified Sn-36at.%Ni peritectic alloys is investigated at different deceleration rates. Extensive detachment of secondary dendrite arms from primary stem is observed below peritectic reaction temperature TP. And an analytical model is established to characterize the detachment process in terms of the secondary dendrite arm spacing λ2, the root radius of detached arms and the specific surface area (SV) of dendrites. It is found that the detachment mechanism is caused by not only curvature difference between the tips and roots of secondary branches, but also that between the thicker secondary branches and the thinner ones. Besides, this detachment process is significantly accelerated by the temperature gradient zone melting (TGZM) effect during peritectic solidification. It is demonstrated that the reaction constant (f) which is used to characterize the kinetics of peritectic reaction is crucial for the determination of the detachment process. The value of f not only changes with growth rate but also with solidification time at a given deceleration rate. In conclusion, these findings help the better understanding of the detachment mechanism. PMID:27270334

  11. Dendritic cell analysis in primary immunodeficiency

    PubMed Central

    Bigley, Venetia; Barge, Dawn; Collin, Matthew

    2016-01-01

    Purpose of review Dendritic cells are specialized antigen-presenting cells which link innate and adaptive immunity, through recognition and presentation of antigen to T cells. Although the importance of dendritic cells has been demonstrated in many animal models, their contribution to human immunity remains relatively unexplored in vivo. Given their central role in infection, autoimmunity, and malignancy, dendritic cell deficiency or dysfunction would be expected to have clinical consequences. Recent findings Human dendritic cell deficiency disorders, related to GATA binding protein 2 (GATA2) and interferon regulatory factor 8 (IRF8) mutations, have highlighted the importance of dendritic cells and monocytes in primary immunodeficiency diseases and begun to shed light on their nonredundant roles in host defense and immune regulation in vivo. The contribution of dendritic cell and monocyte dysfunction to the pathogenesis of primary immunodeficiency disease phenotypes is becoming increasingly apparent. However, dendritic cell analysis is not yet a routine part of primary immunodeficiency disease workup. Summary Widespread uptake of dendritic cell/monocyte screening in clinical practice will facilitate the discovery of novel dendritic cell and monocyte disorders as well as advancing our understanding of human dendritic cell biology in health and disease. PMID:27755182

  12. Tail-anchored Protein Insertion in Mammals

    PubMed Central

    Cardani, Silvia; Maroli, Annalisa; Vitiello, Adriana; Soffientini, Paolo; Crespi, Arianna; Bram, Richard F.

    2016-01-01

    The GET (guided entry of tail-anchored proteins)/TRC (transmembrane recognition complex) pathway for tail-anchored protein targeting to the endoplasmic reticulum (ER) has been characterized in detail in yeast and is thought to function similarly in mammals, where the orthologue of the central ATPase, Get3, is known as TRC40 or Asna1. Get3/TRC40 function requires an ER receptor, which in yeast consists of the Get1/Get2 heterotetramer and in mammals of the WRB protein (tryptophan-rich basic protein), homologous to yeast Get1, in combination with CAML (calcium-modulating cyclophilin ligand), which is not homologous to Get2. To better characterize the mammalian receptor, we investigated the role of endogenous WRB and CAML in tail-anchored protein insertion as well as their association, concentration, and stoichiometry in rat liver microsomes and cultured cells. Functional proteoliposomes, reconstituted from a microsomal detergent extract, lost their activity when made with an extract depleted of TRC40-associated proteins or of CAML itself, whereas in vitro synthesized CAML and WRB together were sufficient to confer insertion competence to liposomes. CAML was found to be in ∼5-fold excess over WRB, and alteration of this ratio did not inhibit insertion. Depletion of each subunit affected the levels of the other one; in the case of CAML silencing, this effect was attributable to destabilization of the WRB transcript and not of WRB protein itself. These results reveal unanticipated complexity in the mutual regulation of the TRC40 receptor subunits and raise the question as to the role of the excess CAML in the mammalian ER. PMID:27226539

  13. Method of inhibiting dislocation generation in silicon dendritic webs

    DOEpatents

    Spitznagel, John A.; Seidensticker, Raymond G.; McHugh, James P.

    1990-11-20

    A method of tailoring the heat balance of the outer edge of the dendrites adjacent the meniscus to produce thinner, smoother dendrites, which have substantially less dislocation sources contiguous with the dendrites, by changing the view factor to reduce radiation cooling or by irradiating the dendrites with light from a quartz lamp or a laser to raise the temperature of the dendrites.

  14. Generation of dendrite fragments and their transport from within the mushy zone

    NASA Astrophysics Data System (ADS)

    Liu, Shan

    Five steps have been identified for the grain structure evolution of a casting by an intrinsic mechanism: (i) fragmentation of dendrites in the mushy region; (ii) transport of these dendrite fragments from within this region; (iii) their survival in the bulk liquid; (iv) growth of the survivors; and (v) blockage of the columnar crystal growth front and formation of the equiaxed grains in a casting. Of these, the first two steps remain unclear and are explored in this study. It is found that deceleration of the growth interface leads to fragmentation of side arms from primary stems. This process can be characterized by the Fragmentation Percentage which is related to the magnitude and range of the deceleration, time, and the alloy composition. With decelerations, though temperature gradient at the interface does not change, the dendrite array exhibits important microstructural variations: the dendrite, tip restabilizes rather rapidly (<10 min) and correlates well with the instantaneous tip velocity; and the primary arm spacing restabilization takes ˜5 times longer than the tip readjustment. The difference between the rates of restabilization of the tip radius and primary arm spacing causes slight solute enrichment in the interdendritic region, resulting in side arm detachment. Through a comparative study with the steady state growth process, the magnitude of this solute enrichment is estimated. Further analysis for the dissolution kinetics shows that the excessive solute can only cause a partial dissolution at the neck of a side arm, but this is sufficient to upset the curvature balance between the different sections of a dendritic structure and the continual dissolution at the neck is subsequently driven by the curvature difference until a side arm is detached from the primary stalk. The solidification interface of most castings generally proceeds in a decelerated manner; therefore dendrite fragments already exist in the mushy region. These dendrite fragments can

  15. Lipid dynamics at dendritic spines

    PubMed Central

    Dotti, Carlos Gerardo; Esteban, Jose Antonio; Ledesma, María Dolores

    2014-01-01

    Dynamic changes in the structure and composition of the membrane protrusions forming dendritic spines underlie memory and learning processes. In recent years a great effort has been made to characterize in detail the protein machinery that controls spine plasticity. However, we know much less about the involvement of lipids, despite being major membrane components and structure determinants. Moreover, protein complexes that regulate spine plasticity depend on specific interactions with membrane lipids for proper function and accurate intracellular signaling. In this review we gather information available on the lipid composition at dendritic spine membranes and on its dynamics. We pay particular attention to the influence that spine lipid dynamism has on glutamate receptors, which are key regulators of synaptic plasticity. PMID:25152717

  16. Lipid dynamics at dendritic spines.

    PubMed

    Dotti, Carlos Gerardo; Esteban, Jose Antonio; Ledesma, María Dolores

    2014-01-01

    Dynamic changes in the structure and composition of the membrane protrusions forming dendritic spines underlie memory and learning processes. In recent years a great effort has been made to characterize in detail the protein machinery that controls spine plasticity. However, we know much less about the involvement of lipids, despite being major membrane components and structure determinants. Moreover, protein complexes that regulate spine plasticity depend on specific interactions with membrane lipids for proper function and accurate intracellular signaling. In this review we gather information available on the lipid composition at dendritic spine membranes and on its dynamics. We pay particular attention to the influence that spine lipid dynamism has on glutamate receptors, which are key regulators of synaptic plasticity.

  17. Dendritic Spine Pathology in Schizophrenia

    PubMed Central

    Glausier, Jill R.; Lewis, David A.

    2012-01-01

    Schizophrenia is a neurodevelopmental disorder whose clinical features include impairments in perception, cognition and motivation. These impairments reflect alterations in neuronal circuitry within and across multiple brain regions that are due, at least in part, to deficits in dendritic spines, the site of most excitatory synaptic connections. Dendritic spine alterations have been identified in multiple brain regions in schizophrenia, but are best characterized in layer 3 of the neocortex, where pyramidal cell spine density is lower. These spine deficits appear to arise during development, and thus are likely the result of disturbances in the molecular mechanisms that underlie spine formation, pruning, and/or maintenance. Each of these mechanisms may provide insight into novel therapeutic targets for preventing or repairing the alterations in neural circuitry that mediate the debilitating symptoms of schizophrenia. PMID:22546337

  18. Dendritic cells in Graves' disease.

    PubMed

    Purnamasari, Dyah; Soewondo, Pradana; Djauzi, Samsuridjal

    2015-01-01

    Dendritic cells are major antigen-presenting cells (APC) that stimulate naive T cells, which induce adaptive immune responses. Graves' disease (GD) is an autoimmune disease characterized by the presence of autoantibodies against Thyroid Stimulating Hormone Receptor (TSHR). The autoantibodies bind with TSHR and stimulate thyroid hormone production. Dendritic cells are still the major APC in GD immune response although thyrocytes in GD can also express Major Histocompatibility Class (MHC) class II molecule. Studies about DC in GD have been conducted by isolating intra-thyroid DC or DC in peripheral circulation. Results of DC studies in GD are still controversial. Changes in number and profile of DC are found, which indicate altered immune response activity and defects of regulator T cell (Treg) in GD.

  19. Anchor Toolkit - a secure mobile agent system

    SciTech Connect

    Mudumbai, Srilekha S.; Johnston, William; Essiari, Abdelilah

    1999-05-19

    Mobile agent technology facilitates intelligent operation insoftware systems with less human interaction. Major challenge todeployment of mobile agents include secure transmission of agents andpreventing unauthorized access to resources between interacting systems,as either hosts, or agents, or both can act maliciously. The Anchortoolkit, designed by LBNL, handles the transmission and secure managementof mobile agents in a heterogeneous distributed computing environment. Itprovides users with the option of incorporating their security managers.This paper concentrates on the architecture, features, access control anddeployment of Anchor toolkit. Application of this toolkit in a securedistributed CVS environment is discussed as a case study.

  20. Growth and morphology control of carbon nanotubes at the apexes of pyramidal silicon tips

    NASA Astrophysics Data System (ADS)

    Edgeworth, J. P.; Burt, D. P.; Dobson, P. S.; Weaver, J. M. R.; Macpherson, J. V.

    2010-03-01

    We describe the development of catalysed chemical vapour deposition (cCVD) growth schemes suitable for the production of carbon nanotube atomic force microscopy (CNT-AFM) probes. Growth and sample processing conditions are utilized that both incorporate safety in the process, e.g. the use of ethanol (EtOH) vapour as a carbon feedstock and hydrogen at only 4% (flow proportion), and simplicity, e.g. no catalyst patterning is required. Cobalt is employed as the growth catalyst and thin films of aluminium on silicon as the substrate material. Purpose-fabricated silicon substrates containing large numbers of tip structures are used as models of AFM probes. This enables growth to be carried out on many tips at once, facilitating a thorough investigation of the effect of different growth schemes on yields. cCVD growth schemes are chosen which produce stabilizing high density networks of carbon nanotubes on the sidewalls of the pyramidal tips to aid in anchoring the apex protruding carbon nanotube(s) in place. This results in long-lasting AFM imaging tips. We demonstrate that through rational tailoring of cCVD conditions it is possible to tune the growth conditions such that CNTs which protrude straight from tip apexes can be obtained at yields of greater than or equal to 78%. Application of suitable growth schemes to CNT growth on commercially available AFM probes resulted in CNT-AFM probes which were found to be extremely useful for extended lifetime metrological profiling of complex structures.

  1. Scanning tip microwave near field microscope

    DOEpatents

    Xiang, Xiao-Dong; Schultz, Peter G.; Wei, Tao

    1998-01-01

    A microwave near field microscope has a novel microwave probe structure wherein the probing field of evanescent radiation is emitted from a sharpened metal tip instead of an aperture or gap. This sharpened tip, which is electrically and mechanically connected to a central electrode, extends through and beyond an aperture in an endwall of a microwave resonating device such as a microwave cavity resonator or a microwave stripline resonator. Since the field intensity at the tip increases as the tip sharpens, the total energy which is radiated from the tip and absorbed by the sample increases as the tip sharpens. The result is improved spatial resolution without sacrificing sensitivity.

  2. Scanning tip microwave near field microscope

    DOEpatents

    Xiang, X.D.; Schultz, P.G.; Wei, T.

    1998-10-13

    A microwave near field microscope has a novel microwave probe structure wherein the probing field of evanescent radiation is emitted from a sharpened metal tip instead of an aperture or gap. This sharpened tip, which is electrically and mechanically connected to a central electrode, extends through and beyond an aperture in an end wall of a microwave resonating device such as a microwave cavity resonator or a microwave stripline resonator. Since the field intensity at the tip increases as the tip sharpens, the total energy which is radiated from the tip and absorbed by the sample increases as the tip sharpens. The result is improved spatial resolution without sacrificing sensitivity. 17 figs.

  3. On the role of convective motion during dendrite growth: Experiments under variable gravity, revised

    NASA Technical Reports Server (NTRS)

    Hallett, J.; Cho, N.; Harrison, K.; Lord, A.; Wedum, E.; Purcell, R.; Saunders, C. P. R.

    1987-01-01

    Experiments show the effect of self induced convection on individual dendrite growth in uniformly supercooled samples and solidification of the resulting mush under conditions of high and low g. Convection is visualized by a Schlieren optical system or a Mach Zender interferometer. For ice crystals growing from the vapor in air, a slight reduction in linear growth rate occur under low g. For ice crystals growing from NaCl solution, dendrite tip velocities are unchanged, but subsequent mush solidification is enhanced through drainage channels under higher g. By contrast, sodium sulfate decahydrate dendrites growing from solution produce convective plumes which lead to higher tip growth rate only as the crystal growth direction approaches that of gravity. Convective plumes are laminar for small crystals under conditions of these experiments; the rise velocity of such plumes is greater than individual vortex rings under identical conditions. Convection effects are only present in solution under a critical supercooling less than about 5 C for sodium sulfate and 2 C for ice in NaCl since at higher supercooling the crystallization velocity, proportional to the square of the supercooling, exceeds the convective velocity, proportional to the square root of the supercooling. The role of convective velocity in bulk solidification is to give a large scale flow which under extreme cases may lead to extensive secondary crystal production, which alters the resulting crystal texture of the completely solidified melt.

  4. Influence of convection on free growth of dendrite crystals from solution

    NASA Technical Reports Server (NTRS)

    Hallett, J.; Wedum, E.

    1979-01-01

    The free growth of dendrites in a uniformly supercooled solution was examined using cine photography with a Schlieren optical system. Crystals were grown in the bulk of the solution from a centrally located capillary tube, nucleated at the interface with a liquid nitrogen cooled wire. Crystals propagated along the tube, the slower growing orientations eliminated, and emerged at the tip, usually growing parallel to the tube direction. For both sodium sulfate decahydrate from its solution and ice from sodium chloride solution, growth rate and fineness of dendrites increased with supercooling. In sodium sulfate, upward convection of the less dense depleted solution occurs; downward convection was observed for the rejected, more concentrated sodium chloride solution. In both cases, there was a spatial and temporal delay in the release of the convective plume from the moving dendrite tip. The role of this convection on the growth characteristics and the production of secondary crystals is examined. A proposed low-g experiment to examine differences in growth rate, crystal texture, and secondary nucleation in a reduced convective regime where molecular diffusion is the dominant transfer process is discussed.

  5. Mechanisms of dendritic growth investigated by in situ light microscopy during electrodeposition and dissolution of lithium

    NASA Astrophysics Data System (ADS)

    Steiger, Jens; Kramer, Dominik; Mönig, Reiner

    2014-09-01

    Batteries with metallic lithium anodes offer improved volumetric and gravimetric energy densities; therefore, future batteries including the promising lithium-sulfur and lithium-air systems would benefit from them. The electrodeposition of lithium metal - which is an unwanted incident in lithium ion systems - often results in fine filaments or moss, called dendritic lithium, which leads to strong capacity fading and the danger of internal short circuiting. To study the mechanisms of dendritic growth and the behavior during lithium dissolution, lithium deposits have been observed in situ in 1 M LiPF6 in EC:DMC by light microscopy. The high resolution optical microscopy provided information on the growth and electrodissolution of single lithium filaments. The growth areas could be identified in detail: The lithium wires can grow either from the substrate-lithium interface, at kinks or in a region at or close to the tip. Based on these observations, we suggest a growth model for lithium filaments predicated on defect-based insertion of lithium at the aforementioned locations. This type of growth is not compatible with previous models of dendritic growth, for example, it is hardly influenced by electric fields at the tip and does not depend on the direction of the electric field.

  6. Free Dendritic Growth of Succinonitrile-Acetone Alloys with Thermosolutal Melt Convection

    NASA Technical Reports Server (NTRS)

    Beckermann, Christoph; Li, Ben Q.

    2003-01-01

    A stagnant film model of the effects of thermosolutal convection on free dendritic growth of alloys is developed, and its predictions are compared to available earth-based experimental data for succinonitrileacetone alloys. It is found that the convection model gives excellent agreement with the measured dendrite tip velocities and radii for low solute concentrations. However, at higher solute concentrations the present predictions show some deviations from the measured data, and the measured (thermal) Peclet numbers tend to fall even below the predictions from diffusion theory. Furthermore, the measured selection parameter (sigma*) is significantly above the expected value of 0.02 and exhibits strong scatter. It is shown that convection is not responsible for these discrepancies. Some of the deviations between the predicted and measured data at higher supercoolings could be caused by measurement difficulties. The systematic disagreement in the selection parameter for higher solute concentrations and all supercoolings examined, indicates that the theory for the selection of the dendrite tip operating state in alloys may need to be reexamined.

  7. Turbine blade tip flow discouragers

    DOEpatents

    Bunker, Ronald Scott

    2000-01-01

    A turbine assembly comprises a plurality of rotating blade portions in a spaced relation with a stationery shroud. The rotating blade portions comprise a root section, a tip portion and an airfoil. The tip portion has a pressure side wall and a suction side wall. A number of flow discouragers are disposed on the blade tip portion. In one embodiment, the flow discouragers extend circumferentially from the pressure side wall to the suction side wall so as to be aligned generally parallel to the direction of rotation. In an alternative embodiment, the flow discouragers extend circumferentially from the pressure side wall to the suction side wall so as to be aligned at an angle in the range between about 0.degree. to about 60.degree. with respect to a reference axis aligned generally parallel to the direction of rotation. The flow discouragers increase the flow resistance and thus reduce the flow of hot gas flow leakage for a given pressure differential across the blade tip portion so as to improve overall turbine efficiency.

  8. [Management of patients with TIPS].

    PubMed

    Dailleau, Édith; Dos Santos, Sophie; Garçon, Adrien; Russeil, Cécile; Brajon, Stéphanie

    2015-01-01

    The Transjugular Intrahepatic Portosystemic Shunt (TIPS) procedure is now performed in almost twenty hospitals in France, including Tours university hospital. The aim is to reduce portal hypertension (PHT) by diverting the portal system to the caval system within the liver. The main cause of PHT is cirrhosis, which may be of alcoholic, viral, dysmetabolic or autoimmune origin.

  9. STRV Cryocooler Tip Motion Suppression

    NASA Technical Reports Server (NTRS)

    Glaser, R.; Ross, R. G., Jr.; Johnson, D. L.

    1994-01-01

    The Space Technology Research Vehicle (STRV-1b) scheduled to fly at the beginning of June 1994, has a cryocooler vibration suppression experiment aboard doing motion suppression of the tip of the coldfinger. STRV-1b is a bread box sized satellite to be launched on the next flight of the Ariane-4.

  10. Blade tip timing (BTT) uncertainties

    NASA Astrophysics Data System (ADS)

    Russhard, Pete

    2016-06-01

    Blade Tip Timing (BTT) is an alternative technique for characterising blade vibration in which non-contact timing probes (e.g. capacitance or optical probes), typically mounted on the engine casing (figure 1), and are used to measure the time at which a blade passes each probe. This time is compared with the time at which the blade would have passed the probe if it had been undergoing no vibration. For a number of years the aerospace industry has been sponsoring research into Blade Tip Timing technologies that have been developed as tools to obtain rotor blade tip deflections. These have been successful in demonstrating the potential of the technology, but rarely produced quantitative data, along with a demonstration of a traceable value for measurement uncertainty. BTT technologies have been developed under a cloak of secrecy by the gas turbine OEM's due to the competitive advantages it offered if it could be shown to work. BTT measurements are sensitive to many variables and there is a need to quantify the measurement uncertainty of the complete technology and to define a set of guidelines as to how BTT should be applied to different vehicles. The data shown in figure 2 was developed from US government sponsored program that bought together four different tip timing system and a gas turbine engine test. Comparisons showed that they were just capable of obtaining measurement within a +/-25% uncertainty band when compared to strain gauges even when using the same input data sets.

  11. Teaching Tips: Improving College Instruction.

    ERIC Educational Resources Information Center

    McGlynn, Angela Provitera

    Designed to help teachers improve instruction, this handbook provides tips gathered from focus groups of teachers and students at New Jersey's Mercer County Community College, as well as from other teaching resources. The first part focuses on the contribution of faculty-student interaction to student success, listing 21 suggestions for building…

  12. 99 Tips for Safe Schools.

    ERIC Educational Resources Information Center

    Kaufer, Steve

    This pamphlet highlights 99 tips for maintaining safe schools. Areas of interest include: alarm systems and control of access, vandalism, parent education, transportation, school design, personnel training, and graffiti. The majority of the pointers deal with maintaining and implementing various forms of electronic surveillance and strategies for…

  13. Assigning Effective Homework. Classroom Tips

    ERIC Educational Resources Information Center

    American Federation of Teachers (NJ), 2010

    2010-01-01

    Each new school year brings high hopes, great expectations and challenges for both new and seasoned educators. The American Federation of Teachers (AFT) has developed a series called "Classroom Tips" to help educators start the year right and anticipate the year ahead. Over the past 40 years, most research studies on homework have found that…

  14. Advanced Password Tips and Tricks

    MedlinePlus

    ... computer security . Tagged with: computer security , data breach , identity theft , online , online safety , password Blog Topics: Privacy, Identity & ... Security Blog Advanced password tips and tricks Video & Media Scam Alerts Get privacy and identity updates by email Looking for business guidance on ...

  15. Library Management Tips that Work

    ERIC Educational Resources Information Center

    Smallwood, Carol, Ed.

    2011-01-01

    There's no shortage of library management books out there--but how many of them actually tackle the little details of day-to-day management, the hard-to-categorize things that slip through the cracks of a larger handbook? "Library Management Tips that Work" does exactly that, addressing dozens of such issues facing library managers, including: (1)…

  16. Safe and Sound Cycling Tips.

    ERIC Educational Resources Information Center

    Garrett, Roberta L.

    1980-01-01

    Teachers at the Ludington (Michigan) Catholic School planned a week-long program on bicycle safety. This article describes some of the week's activities, presents safety tips from speakers, and includes copies of a bicycle safety quiz and a checklist for bicycle maintenance. (SJL)

  17. Library Management Tips that Work

    ERIC Educational Resources Information Center

    Smallwood, Carol, Ed.

    2011-01-01

    There's no shortage of library management books out there--but how many of them actually tackle the little details of day-to-day management, the hard-to-categorize things that slip through the cracks of a larger handbook? "Library Management Tips that Work" does exactly that, addressing dozens of such issues facing library managers, including: (1)…

  18. STRV Cryocooler Tip Motion Suppression

    NASA Technical Reports Server (NTRS)

    Glaser, R.; Ross, R. G., Jr.; Johnson, D. L.

    1994-01-01

    The Space Technology Research Vehicle (STRV-1b) scheduled to fly at the beginning of June 1994, has a cryocooler vibration suppression experiment aboard doing motion suppression of the tip of the coldfinger. STRV-1b is a bread box sized satellite to be launched on the next flight of the Ariane-4.

  19. Tips for Buying Exercise Equipment

    MedlinePlus

    ... Vea esta página en español Tips for Buying Exercise Equipment Related Items Weight Loss Challenge Free Trials ... altered photo? What to Do Before You Buy Exercise Equipment You’ve done your job and looked ...

  20. Engineered liquid crystal anchoring energies with nanopatterned surfaces.

    PubMed

    Gear, Christopher; Diest, Kenneth; Liberman, Vladimir; Rothschild, Mordechai

    2015-01-26

    The anchoring energy of liquid crystals was shown to be tunable by surface nanopatterning of periodic lines and spaces. Both the pitch and height were varied using hydrogen silsesquioxane negative tone electron beam resist, providing for flexibility in magnitude and spatial distribution of the anchoring energy. Using twisted nematic liquid crystal cells, it was shown that this energy is tunable over an order of magnitude. These results agree with a literature model which predicts the anchoring energy of sinusoidal grooves.

  1. Anchor-induced chondral damage in the hip.

    PubMed

    Matsuda, Dean K; Bharam, Srino; White, Brian J; Matsuda, Nicole A; Safran, Marc

    2015-01-01

    The purpose of this study is to investigate the outcomes from anchor-induced chondral damage of the hip, both with and without frank chondral penetration. A multicenter retrospective case series was performed of patients with chondral deformation or penetration during initial hip arthroscopic surgery. Intra-operative findings, post-surgical clinical courses, hip outcome scores and descriptions of arthroscopic treatment in cases requiring revision surgery and anchor removal are reported. Five patients (three females) of mean age 32 years (range, 16-41 years) had documented anchor-induced chondral damage with mean 3.5 years (range, 1.5-6.0 years) follow-up. The 1 o'clock position (four cases) and anterior and mid-anterior portals (two cases each) were most commonly implicated. Two cases of anchor-induced acetabular chondral deformation without frank penetration had successful clinical and radiographic outcomes, while one case progressed from deformation to chondral penetration with clinical worsening. Of the cases that underwent revision hip arthroscopy, all three had confirmed exposed hard anchors which were removed. Two patients have had clinical improvement and one patient underwent early total hip arthroplasty. Anchor-induced chondral deformation without frank chondral penetration may be treated with close clinical and radiographic monitoring with a low threshold for revision surgery and anchor removal. Chondral penetration should be treated with immediate removal of offending hard anchor implants. Preventative measures include distal-based portals, small diameter and short anchors, removable hard anchors, soft suture-based anchors, curved drill and anchor insertion instrumentation and attention to safe trajectories while visualizing the acetabular articular surface.

  2. Nonrotating, self-centering anchor assembly for anchoring a bolt in a borehole

    DOEpatents

    Bevan, John E.; King, Grant W.

    1998-01-01

    An expandable anchor assembly is provided for anchoring the threaded end portion of an elongated roof bolt in a borehole. The anchoring assembly includes a hollow outer sleeve in the form of a plurality of symmetrically arranged, longitudinal segmented wall portions with exterior gripping teeth and an inner expander sleeve in the form of a corresponding plurality of longitudinal wall portions symmetrically arranged about a central axis to define an inner threaded cylindrical section. The inner sleeve is captured within and moveable axially relative to the outer sleeve. As the threaded end portion of the elongated bolt is inserted into the inner threaded cylindrical section of the inner sleeve from the trailing end to the leading end thereof, the inner sleeve expands over and clamps around the threaded end portion of the elongated bolt. Thereafter, partial withdrawal of the elongated bolt from the borehole causes the inner sleeve to axially move relative to the outer sleeve from the leading end toward the trailing end of the outer sleeve in a wedging action to cause the outer sleeve to radially expand and force engagement of the gripping teeth against the sidewall of the borehole to thereby secure the expandable anchor assembly and therewith the threaded end portion of the elongated bolt within the borehole.

  3. Nonrotating, self-centering anchor assembly for anchoring a bolt in a borehole

    DOEpatents

    Bevan, J.E.; King, G.W.

    1998-12-08

    An expandable anchor assembly is provided for anchoring the threaded end portion of an elongated roof bolt in a borehole. The anchoring assembly includes a hollow outer sleeve in the form of a plurality of symmetrically arranged, longitudinal segmented wall portions with exterior gripping teeth and an inner expander sleeve in the form of a corresponding plurality of longitudinal wall portions symmetrically arranged about a central axis to define an inner threaded cylindrical section. The inner sleeve is captured within and moveable axially relative to the outer sleeve. As the threaded end portion of the elongated bolt is inserted into the inner threaded cylindrical section of the inner sleeve from the trailing end to the leading end thereof, the inner sleeve expands over and clamps around the threaded end portion of the elongated bolt. Thereafter, partial withdrawal of the elongated bolt from the borehole causes the inner sleeve to axially move relative to the outer sleeve from the leading end toward the trailing end of the outer sleeve in a wedging action to cause the outer sleeve to radially expand and force engagement of the gripping teeth against the sidewall of the borehole to thereby secure the expandable anchor assembly and therewith the threaded end portion of the elongated bolt within the borehole. 8 figs.

  4. Nonrotating, self-centering anchor assembly for anchoring a bolt in a borehole

    SciTech Connect

    Bevan, John E.; King, Grant W.

    1997-12-01

    An expandable anchor assembly is provided for anchoring the threaded end portion of an elongated roof bolt in a borehole. The anchoring assembly includes a hollow outer sleeve in the form of a plurality of symmetrically arranged, longitudinal segmented wall portions with exterior gripping teeth and an inner expander sleeve in the form of a corresponding plurality of longitudinal wall portions symmetrically arranged about a central axis to define an inner threaded cylindrical section. The inner sleeve is captured within and moveable axially relative to the outer sleeve. As the threaded end portion of the elongated bolt is inserted into the inner threaded cylindrical section of the inner sleeve from the trailing end to the leading end thereof, the inner sleeve expands over and clamps around the threaded end portion of the elongated bolt. Thereafter, partial withdrawal of the elongated bolt from the borehole causes the inner sleeve to axially move relative to the outer sleeve from the leading end toward the trailing end of the outer sleeve in a wedging action to cause the outer sleeve to radially expand and force engagement of the gripping teeth against the sidewall of the borehole to thereby secure the expandable anchor assembly and therewith the threaded end portion of the elongated bolt within the borehole.

  5. Predicting casualties implied by TIPs

    NASA Astrophysics Data System (ADS)

    Trendafiloski, G.; Wyss, M.; Wyss, B. M.

    2009-12-01

    When an earthquake is predicted, forecast, or expected with a higher than normal probability, losses are implied. We estimated the casualties (fatalities plus injured) that should be expected if earthquakes in TIPs (locations of Temporarily Increased Probability of earthquakes) defined by Kossobokov et al. (2009) should occur. We classified the predictions of losses into the categories red (more than 400 fatalities or more than 1,000 injured), yellow (between 100 and 400 fatalities), green (fewer than 100 fatalities), and gray (undetermined). TIPs in Central Chile, the Philippines, Papua, and Taiwan are in the red class, TIPs in Southern Sumatra, Nicaragua, Vanatu, and Honshu in the yellow class, and TIPs in Tonga, Loyalty Islands, Vanatu, S. Sandwich Islands, Banda Sea, and the Kuriles, are classified as green. TIPs where the losses depend moderately on the assumed point of major energy release were classified as yellow; TIPs such as in the Talaud Islands and in Tonga, where the losses depend very strongly on the location of the epicenter, were classified as gray. The accuracy of loss estimates after earthquakes with known hypocenter and magnitude are affected by uncertainties in transmission and soil properties, the composition of the building stock, the population present, and the method by which the numbers of casualties are calculated. In the case of TIPs, uncertainties in magnitude and location are added, thus we calculate losses for a range of these two parameters. Therefore, our calculations can only be considered order of magnitude estimates. Nevertheless, our predictions can come to within a factor of two of the observed numbers, as in the case of the M7.6 earthquake of October 2005 in Pakistan that resulted in 85,000 fatalities (Wyss, 2005). In subduction zones, the geometrical relationship between the earthquake source capable of a great earthquake and the population is clear because there is only one major fault plane available, thus the epicentral

  6. Distribution of the receptor-anchoring protein gephyrin in the rat dentate gyrus and changes following entorhinal cortex lesion.

    PubMed

    Simbürger, E; Plaschke, M; Kirsch, J; Nitsch, R

    2000-04-01

    We analyzed the distribution of the receptor-anchoring protein gephyrin in the normal and deafferented rat dentate gyrus to investigate whether the expression of this postsynaptic protein is altered in response to the formation of new synaptic contacts. Confocal microscopy and digital image analysis revealed that in normal dentate gyrus immunolabeling was most prominent in the outer molecular layer and decreased successively in the direction of the granule cell layer. Simultaneous immunolabeling for gephyrin and cell-specific markers showed that granule cells and parvalbumin-positive interneurons express gephyrin. Large, intensely stained, gephyrin-positive clusters were distributed along distinct dendrites, and most of them were positive for parvalbumin. Calbindin-immunostained dendrites were associated with smaller, gephyrin-positive clusters. Lesion of the medial entorhinal cortex leads to deafferentiation of the middle molecular layer which resulted in an increased gephyrin immunoreactivity. These changes were due to a significantly increased concentration of the very small gephyrin-positive clusters. Parvalbumin-positive dendrites did not display any increase in co-localizing gephyrin-positive structures. The altered immunolabeling pattern persisted until 12 weeks after lesion, a time when the process of synaptic reorganization is complete. Our findings suggest that synaptogenesis following deafferentiation results in a cell-specific redistribution of gephyrin immunoreactivity at specific inhibitory synapses.

  7. Cell-intrinsic drivers of dendrite morphogenesis.

    PubMed

    Puram, Sidharth V; Bonni, Azad

    2013-12-01

    The proper formation and morphogenesis of dendrites is fundamental to the establishment of neural circuits in the brain. Following cell cycle exit and migration, neurons undergo organized stages of dendrite morphogenesis, which include dendritic arbor growth and elaboration followed by retraction and pruning. Although these developmental stages were characterized over a century ago, molecular regulators of dendrite morphogenesis have only recently been defined. In particular, studies in Drosophila and mammalian neurons have identified numerous cell-intrinsic drivers of dendrite morphogenesis that include transcriptional regulators, cytoskeletal and motor proteins, secretory and endocytic pathways, cell cycle-regulated ubiquitin ligases, and components of other signaling cascades. Here, we review cell-intrinsic drivers of dendrite patterning and discuss how the characterization of such crucial regulators advances our understanding of normal brain development and pathogenesis of diverse cognitive disorders.

  8. Dendritic web silicon for solar cell application

    NASA Technical Reports Server (NTRS)

    Seidensticker, R. G.

    1977-01-01

    The dendritic web process for growing long thin ribbon crystals of silicon and other semiconductors is described. Growth is initiated from a thin wirelike dendrite seed which is brought into contact with the melt surface. Initially, the seed grows laterally to form a button at the melt surface; when the seed is withdrawn, needlelike dendrites propagate from each end of the button into the melt, and the web portion of the crystal is formed by the solidification of the liquid film supported by the button and the bounding dendrites. Apparatus used for dendritic web growth, material characteristics, and the two distinctly different mechanisms involved in the growth of a single crystal are examined. The performance of solar cells fabricated from dendritic web material is indistinguishable from the performance of cells fabricated from Czochralski grown material.

  9. Active Dendrites Enhance Neuronal Dynamic Range

    PubMed Central

    Gollo, Leonardo L.; Kinouchi, Osame; Copelli, Mauro

    2009-01-01

    Since the first experimental evidences of active conductances in dendrites, most neurons have been shown to exhibit dendritic excitability through the expression of a variety of voltage-gated ion channels. However, despite experimental and theoretical efforts undertaken in the past decades, the role of this excitability for some kind of dendritic computation has remained elusive. Here we show that, owing to very general properties of excitable media, the average output of a model of an active dendritic tree is a highly non-linear function of its afferent rate, attaining extremely large dynamic ranges (above 50 dB). Moreover, the model yields double-sigmoid response functions as experimentally observed in retinal ganglion cells. We claim that enhancement of dynamic range is the primary functional role of active dendritic conductances. We predict that neurons with larger dendritic trees should have larger dynamic range and that blocking of active conductances should lead to a decrease in dynamic range. PMID:19521531

  10. Dendritic web silicon for solar cell application

    NASA Technical Reports Server (NTRS)

    Seidensticker, R. G.

    1977-01-01

    The dendritic web process for growing long thin ribbon crystals of silicon and other semiconductors is described. Growth is initiated from a thin wirelike dendrite seed which is brought into contact with the melt surface. Initially, the seed grows laterally to form a button at the melt surface; when the seed is withdrawn, needlelike dendrites propagate from each end of the button into the melt, and the web portion of the crystal is formed by the solidification of the liquid film supported by the button and the bounding dendrites. Apparatus used for dendritic web growth, material characteristics, and the two distinctly different mechanisms involved in the growth of a single crystal are examined. The performance of solar cells fabricated from dendritic web material is indistinguishable from the performance of cells fabricated from Czochralski grown material.

  11. Dendritic Ion Channel Trafficking and Plasticity

    PubMed Central

    Shah, Mala M.; Hammond, Rebecca S.; Hoffman, Dax

    2010-01-01

    Dendrites, the elaborate processes emerging from neuronal cell bodies, receive most excitatory synaptic inputs. Voltage- and calcium-gated ion channels are abundant in dendrites and modify the shape, propagation and integration of synaptic signals. These ion channels also determine intrinsic dendritic excitability and are therfore important for the induction and manifestation of Hebbian and non-Hebbian plasticity. Revealingly, dendritic channels have distinct expression patterns and biophysical properties from those present in other neuronal compartments. Recent evidence suggests that dendritic ion channels are locally regulated, perhaps contributing to different forms of plasticity. In this review, we will discuss the implications of regulating dendritic ion channel function and trafficking in the context of plasticity and information processing. PMID:20363038

  12. Transcranial magnetic stimulation (TMS) inhibits cortical dendrites.

    PubMed

    Murphy, Sean C; Palmer, Lucy M; Nyffeler, Thomas; Müri, René M; Larkum, Matthew E

    2016-03-18

    One of the leading approaches to non-invasively treat a variety of brain disorders is transcranial magnetic stimulation (TMS). However, despite its clinical prevalence, very little is known about the action of TMS at the cellular level let alone what effect it might have at the subcellular level (e.g. dendrites). Here, we examine the effect of single-pulse TMS on dendritic activity in layer 5 pyramidal neurons of the somatosensory cortex using an optical fiber imaging approach. We find that TMS causes GABAB-mediated inhibition of sensory-evoked dendritic Ca(2+) activity. We conclude that TMS directly activates fibers within the upper cortical layers that leads to the activation of dendrite-targeting inhibitory neurons which in turn suppress dendritic Ca(2+) activity. This result implies a specificity of TMS at the dendritic level that could in principle be exploited for investigating these structures non-invasively.

  13. New Retrievable Coil Anchors: Preliminary In Vivo Experiences in Swine

    SciTech Connect

    Konya, A. Wright, K.C.

    2005-04-15

    Purpose. To design and test retrievable coil anchors to improve the safety and efficacy of coil embolization. Methods. Fifty-two 0.038-inch homemade retrievable stainless steel coils were equipped with one of four different pre-shaped nitinol anchors and tested in 38 pigs. All coils with the anchor were completely retrieved and redeployed 3-18 times (median 7 times) prior to release. Types 1 and 2 anchored coils were acutely deployed in the external iliac arteries (n = 10 each), and chronically tested (1 week) in the common carotid arteries (n = 6 each). Larger type 1 (n = 4), type 3 (n = 6), and type 4 (n = 4) anchored coils were acutely deployed in the abdominal aorta. The largest type 1 anchors (n = 6) were acutely tested in the inferior vena cava. Results. All anchored coils were successfully retrieved and repositioned several times. All but two coils formed a compact plug and there was no coil migration except with two mechanically defective type 3 anchors. Conclusion. The use of retrievable anchors allowed the coils to be retrieved and repositioned, prevented coil migration, and enabled compact coil configuration.

  14. Infrastructure anchor bolt inspection program with NDE applications

    NASA Astrophysics Data System (ADS)

    Fish, Philip E.

    1996-11-01

    In 1990, Wisconsin Department of Transportation found a high mast light pole with two of six anchor bolts failed. This failure along with published reports from Michigan DOT about anchor bolt failures on cantilever sign structures, raised concern about the quality and condition of anchor bolts on the Wisconsin DOT system. Wisconsin Department of Transportation implemented an Anchor Bolt Inspection Program in 1990 for cantilever sign structures, high mast light towers, interstate light towers, and signal masts. The program requires an experienced inspection team and a practical inspection approach. Inspection preparation includes review of all background information such as design plans, design computations, construction plans, shop plans, and maintenance history. An inspection plan is developed. Special emphasis is placed on determining material type, cut or rolled threads, and type of coating for anchor bolts. Inspection emphasis are on "hands on" and Nondestructive evaluation. Special emphasis is placed on visual conditions of anchor bolts (cut or rolled threads, straightness, corrosion, nut tension etc.) along with ultrasonic inspection. This program places a strong emphasis on Non Destructive Testing (NDT), especially ultrasonic. Procedures and inspection calibrations are developed from similar anchor bolt geometry and material type. Cut notches are placed in the anchor bolts at locations of possible failure. NDT inspection calibrations are performed from these bolts. Report documentation includes all design plans, pictorial documentation of structural deficiencies, sketches, nondestructive evaluation reports, conclusions, and recommendations. This program has been successful in locating failed anchor bolts and critical cracks before failure of an entire structure.

  15. Venue Recommendation and Web Search Based on Anchor Text

    DTIC Science & Technology

    2014-11-01

    experimented with the use of anchor text representations in the language modeling framework, and base our runs ei- ther on full ClueWeb12 or the subset of...anchor text representations in the language modeling framework, and base our runs ei- ther on full ClueWeb12 or the subset of touristic aggregators...ClueWeb12- full anchor text , and run our proposed model based on this dataset. This model is exactly the same as Model-Anchor, but based on the

  16. Inhibition of dendrite formation in mouse melanocytes transiently transfected with antisense DNA to myosin Va

    PubMed Central

    EDGAR, ALASDAIR J.; BENNETT, JONATHAN P.

    1999-01-01

    In mice a molecular motor of the myosin V class (designated myosin Va) is known to be the product of the dilute locus, where a mutation prevents melanosome transport in melanocytes. There is conflicting evidence about whether it has a role in dendrite outgrowth. We investigated its role by transiently transfecting antisense oligonucleotides to inhibit its expression in a melanocyte cell line. We demonstrated mRNA and protein expression of myosin Va in 3 mouse melanocyte lines and 1 human melanoma cell line, using RT-PCR and immunoblotting. Two splice variants were found in human cells whilst only the longer transcript, containing an additional exon, was present in mouse melanocyte lines. The shorter variant was detected in other mouse tissues. Myosin Va protein levels were similar in 3 melanocyte lines with differing amounts of pigmentation, indicating that expression of myosin Va is not tightly coupled to expression of melanin. Immunocytochemistry showed 2 types of myosin Va localisation. A punctate pattern of staining concentrated in the perinuclear region was indicative of organelle association, and the observation of occasional linear punctate staining aligned with F-actin bundles supported the idea that myosin Va has a role in transporting melanosomes along actin filaments. Staining was also intense at tips of dendrites and at sites of dendrite-cell contact, consistent with a possible role in dendrite growth. Transient transfection of antisense phosphorothioate oligodeoxynucleotides targeted against myosin Va mRNA reduced expression of myosin Va protein in cultured mouse melan-a melanocytes by over 70% 20 h after transfection whereas a control (shuffled sequence) oligonucleotide did not. Upon trypsinisation and replating these cells the capacity of the transfected cells to extend new dendrites was reduced in the cells containing the specific antisense oligonucleotides but unaffected by the control oligonucleotide. Image analysis confirmed that the effect of

  17. End-anchored polymers in good solvents from the single chain limit to high anchoring densities.

    PubMed

    Whitmore, Mark D; Grest, Gary S; Douglas, Jack F; Kent, Michael S; Suo, Tongchuan

    2016-11-07

    An increasing number of applications utilize grafted polymer layers to alter the interfacial properties of solid substrates, motivating refinement in our theoretical understanding of such layers. To assess existing theoretical models of them, we have investigated end-anchored polymer layers over a wide range of grafting densities, σ, ranging from a single chain to high anchoring density limits, chain lengths ranging over two orders of magnitude, for very good and marginally good solvent conditions. We compare Monte Carlo and molecular dynamics simulations, numerical self-consistent field calculations, and experimental measurements of the average layer thickness, h, with renormalization group theory, the Alexander-de Gennes mushroom theory, and the classical brush theory. Our simulations clearly indicate that appreciable inter-chain interactions exist at all simulated areal anchoring densities so that there is no mushroom regime in which the layer thickness is independent of σ. Moreover, we find that there is no high coverage regime in which h follows the predicted scaling, h ∼ Nσ(1/3), for classical polymer brushes either. Given that no completely adequate analytic theory seems to exist that spans wide ranges of N and σ, we applied scaling arguments for h as a function of a suitably defined reduced anchoring density, defined in terms of the solution radius of gyration of the polymer chains and N. We find that such a scaling approach enables a smooth, unified description of h in very good solvents over the full range of anchoring density and chain lengths, although this type of data reduction does not apply to marginal solvent quality conditions.

  18. End-anchored polymers in good solvents from the single chain limit to high anchoring densities

    NASA Astrophysics Data System (ADS)

    Whitmore, Mark D.; Grest, Gary S.; Douglas, Jack F.; Kent, Michael S.; Suo, Tongchuan

    2016-11-01

    An increasing number of applications utilize grafted polymer layers to alter the interfacial properties of solid substrates, motivating refinement in our theoretical understanding of such layers. To assess existing theoretical models of them, we have investigated end-anchored polymer layers over a wide range of grafting densities, σ, ranging from a single chain to high anchoring density limits, chain lengths ranging over two orders of magnitude, for very good and marginally good solvent conditions. We compare Monte Carlo and molecular dynamics simulations, numerical self-consistent field calculations, and experimental measurements of the average layer thickness, h, with renormalization group theory, the Alexander-de Gennes mushroom theory, and the classical brush theory. Our simulations clearly indicate that appreciable inter-chain interactions exist at all simulated areal anchoring densities so that there is no mushroom regime in which the layer thickness is independent of σ. Moreover, we find that there is no high coverage regime in which h follows the predicted scaling, h ˜ Nσ1/3, for classical polymer brushes either. Given that no completely adequate analytic theory seems to exist that spans wide ranges of N and σ, we applied scaling arguments for h as a function of a suitably defined reduced anchoring density, defined in terms of the solution radius of gyration of the polymer chains and N. We find that such a scaling approach enables a smooth, unified description of h in very good solvents over the full range of anchoring density and chain lengths, although this type of data reduction does not apply to marginal solvent quality conditions.

  19. The Equiaxed Dendritic Solidification Experiment (EDSE)

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The Equiaxed Dendritic Solidification Experiment (EDSE) is a material sciences investigation under the Formation of Microstructures/pattern formation discipline. The objective is to study the microstructural evolution of and thermal interactions between several equiaxed crystals growing dendritically in a supercooled melt of a pure and transparent substance under diffusion controlled conditions. Dendrites growing at .4 supercooling from a 2 stinger growth chamber for the EDSE in the Microgravity Development Lab (MDL).

  20. GABAAR-dependent synaptic transmission sculpts dendritic arbor structure in Xenopus tadpoles in vivo

    PubMed Central

    Shen, Wanhua; Da Silva, Jorge Santos; He, Haiyan; Cline, Hollis T.

    2009-01-01

    The emergence of dendritic arbor structure in vivo depends on synaptic inputs. We tested whether inhibitory GABAergic synaptic transmission regulates Xenopus optic tectal cell dendritic arbor development in vivo by expressing a peptide corresponding to an intracellular loop (ICL) of the γ2 subunit of GABAAR which is required to anchor GABAA receptors to the postsynaptic scaffold. GFP-tagged ICL (EGFP-ICL) was distributed in a punctate pattern at putative inhibitory synapses, identified by VGAT-immunoreactive puncta. ICL expression completely blocked GABAAR - mediated transmission in 36% of transfected neurons and significantly reduced GABAAR - mediated synaptic currents relative to AMPAR-mediated synaptic currents in the remaining transfected neurons without altering release probability or neuronal excitability. Further analysis of ICL-expressing neurons with residual GABAAR- mediated inputs showed that the capacity of benzodiazepine to enhance GABAergic synaptic responses was reduced in ICL-expressing neurons, indicating that they were likely depleted of γ2 subunit-containing GABAAR. Neurons expressing a mutant form of ICL were comparable to controls. In vivo time-lapse images showed that ICL-expressing neurons have more sparsely branched dendritic arbors which expand over larger neuropil areas than EGFP-expressing control neurons. Analysis of branch dynamics indicated that ICL expression affected arbor growth by reducing rates of branch addition. Furthermore, we found that decreasing GABAergic synaptic transmission with ICL expression blocked visual experience dependent dendritic arbor structural plasticity. Our findings establish an essential role for inhibitory GABAergic synaptic transmission in the regulation of dendritic structural plasticity in Xenopus in vivo. PMID:19369572

  1. Rigid rod anchored to infinite membrane.

    PubMed

    Guo, Kunkun; Qiu, Feng; Zhang, Hongdong; Yang, Yuliang

    2005-08-15

    We investigate the shape deformation of an infinite membrane anchored by a rigid rod. The density profile of the rod is calculated by the self-consistent-field theory and the shape of the membrane is predicted by the Helfrich membrane elasticity theory [W. Helfrich, Z. Naturforsch. 28c, 693 (1973)]. It is found that the membrane bends away from the rigid rod when the interaction between the rod and the membrane is repulsive or weakly attractive (adsorption). However, the pulled height of the membrane at first increases and then decreases with the increase of the adsorption strength. Compared to a Gaussian chain with the same length, the rigid rod covers much larger area of the membrane, whereas exerts less local entropic pressure on the membrane. An evident gap is found between the membrane and the rigid rod because the membrane's curvature has to be continuous. These behaviors are compared with that of the flexible-polymer-anchored membranes studied by previous Monte Carlo simulations and theoretical analysis. It is straightforward to extend this method to more complicated and real biological systems, such as infinite membrane/multiple chains, protein inclusion, or systems with phase separation.

  2. Intravital imaging of dendritic spine plasticity

    PubMed Central

    Sau Wan Lai, Cora

    2014-01-01

    Abstract Dendritic spines are the postsynaptic part of most excitatory synapses in the mammalian brain. Recent works have suggested that the structural and functional plasticity of dendritic spines have been associated with information coding and memories. Advances in imaging and labeling techniques enable the study of dendritic spine dynamics in vivo. This perspective focuses on intravital imaging studies of dendritic spine plasticity in the neocortex. I will introduce imaging tools for studying spine dynamics and will further review current findings on spine structure and function under various physiological and pathological conditions. PMID:28243511

  3. Orientations of dendritic growth during solidification

    NASA Astrophysics Data System (ADS)

    Lee, Dong Nyung

    2017-02-01

    Dendrites are crystalline forms which grow far from the limit of stability of the plane front and adopt an orientation which is as close as possible to the heat flux direction. Dendritic growth orientations for cubic metals, bct Sn, and hcp Zn, can be controlled by thermal conductivity, Young's modulus, and surface energy. The control factors have been elaborated. Since the dendrite is a single crystal, its properties such as thermal conductivity that influences the heat flux direction, the minimum Young's modulus direction that influences the strain energy minimization, and the minimum surface energy plane that influences the crystal/liquid interface energy minimization have been proved to control the dendritic growth direction. The dendritic growth directions of cubic metals are determined by the minimum Young's modulus direction and/or axis direction of symmetry of the minimum crystal surface energy plane. The dendritic growth direction of bct Sn is determined by its maximum thermal conductivity direction and the minimum surface energy plane normal direction. The primary dendritic growth direction of hcp Zn is determined by its maximum thermal conductivity direction and the minimum surface energy plane normal direction and the secondary dendrite arm direction of hcp Zn is normal to the primary dendritic growth direction.

  4. Orientations of dendritic growth during solidification

    NASA Astrophysics Data System (ADS)

    Lee, Dong Nyung

    2017-03-01

    Dendrites are crystalline forms which grow far from the limit of stability of the plane front and adopt an orientation which is as close as possible to the heat flux direction. Dendritic growth orientations for cubic metals, bct Sn, and hcp Zn, can be controlled by thermal conductivity, Young's modulus, and surface energy. The control factors have been elaborated. Since the dendrite is a single crystal, its properties such as thermal conductivity that influences the heat flux direction, the minimum Young's modulus direction that influences the strain energy minimization, and the minimum surface energy plane that influences the crystal/liquid interface energy minimization have been proved to control the dendritic growth direction. The dendritic growth directions of cubic metals are determined by the minimum Young's modulus direction and/or axis direction of symmetry of the minimum crystal surface energy plane. The dendritic growth direction of bct Sn is determined by its maximum thermal conductivity direction and the minimum surface energy plane normal direction. The primary dendritic growth direction of hcp Zn is determined by its maximum thermal conductivity direction and the minimum surface energy plane normal direction and the secondary dendrite arm direction of hcp Zn is normal to the primary dendritic growth direction.

  5. Precipitation dendrites in turbulent pipe flows

    NASA Astrophysics Data System (ADS)

    Angheluta, Luiza; Hawkins, Christopher; Hammer, Øyvind; Jamtveit, Bjørn

    2013-04-01

    Surface precipitation in pipelines, as well as freezing in water pipes is of great concern in many industrial applications where scaling phenomena becomes a control problem of pipe-clogging or an efficiency reduction in transport. Flow blockage often occurs even when only a small fraction is deposited non-uniformly on the walls in the form of dendrites. Dendritic patterns are commonly encountered in surface precipitation from supersaturated solutions, e.g. calcite dendrites, as well as in solidification from undercooled liquids, e.g. freezing of water into ice dendrites. We explore the mathematical similarities between precipitation and freezing processes and, in particular, investigate the effect of fluid flow on the precipitation dendrites on pipe walls. We use a phase field approach to model surface growth coupled with a lattice Boltzmann method that simulates a channel flow at varying Reynolds number. The dendrites orientation and shape depend non-trivially on the ratio between advection and diffusion, i.e. the Peclet number, as well as the Reynolds number. Roughness induced vortices near growing dendrites at high flow rates further affect the branch splitting of dendrites. We show how the transport rate in a pipeline may depend on the different dendritic morphologies, and provide estimates for the flow conditions that correspond to most efficient transport regimes.

  6. The renal microenvironment modifies dendritic cell phenotype.

    PubMed

    Chessa, Federica; Mathow, Daniel; Wang, Shijun; Hielscher, Thomas; Atzberger, Ann; Porubsky, Stefan; Gretz, Norbert; Burgdorf, Sven; Gröne, Hermann-Josef; Popovic, Zoran V

    2016-01-01

    Renal dendritic cells are a major component of the renal mononuclear phagocytic system. In the renal interstitium, these cells are exposed to an osmotic gradient, mainly sodium, whose concentration progressively increases towards inner medulla. Renal allograft rejection affects predominantly the cortex, suggesting a protective role of the renal medullary micromilieu. Whether osmolar variations can modulate the function of renal dendritic cells is currently undefined. Considering the central role of dendritic cells in promoting allorejection, we tested whether the biophysical micromilieu, particularly the interstitial osmotic gradient, influences their alloreactivity. There was a progressive depletion of leukocytes towards the medulla of homeostatic kidney. Only macrophages opposed this tendency. Flow cytometry of homeostatic and post-transplant medullary dendritic cells revealed a switch towards a macrophage-like phenotype. Similarly, bone marrow-derived dendritic cells developed ex vivo in sodium chloride-enriched medium acquired a M2-like signature. Microarray analysis of allotransplant dendritic cells posed a medullary downregulation of genes mainly involved in alloantigen recognition. Gene expression profiles of both medullary dendritic cells and bone marrow-derived dendritic cells matured in hyperosmolar medium had an overlap with the macrophage M2 signature. Thus, the medullary environment inhibits an alloimmune response by modulating the phenotype and function of dendritic cells.

  7. Tips for Postpartum Dads and Partners

    MedlinePlus

    ... Blues: Partners Interview with Wade Bowen Coping with Suicide & Loss Tips for Postpartum Dads and Partners Pregnancy and postpartum mood and anxiety disorders affect the whole family. Here are some tips that ...

  8. Tips for Reducing Pesticide Impacts on Wildlife

    EPA Pesticide Factsheets

    This Web page provides tips for pesticide users in residential and agricultural settings, as well as tips for certified pesticide applicators for ways to protect wildlife from potentially harmful effects of pesticides.

  9. Labyrinthine turbine-rotor-blade tip seal

    NASA Technical Reports Server (NTRS)

    Wagner, William R. (Inventor)

    1987-01-01

    Means for sealing the tip 18 of a rotor turbine blade 10 against tip leakage flow comprising a multiplicity of recesses 30 formed in the surface of the tip 18. The recesses 30 are preferably formed in a labyrinthine or slaggered pattern which interposes at least one recess 30 in every leakage flow path across the tip 18 from the pressure side 26 to the suction side 28 of the blade 10.

  10. Tip cap for a rotor blade

    NASA Technical Reports Server (NTRS)

    Kofel, W. K.; Tuley, E. N.; Gay, C. H., Jr.; Troeger, R. E.; Sterman, A. P. (Inventor)

    1983-01-01

    A replaceable tip cap for attachment to the end of a rotor blade is described. The tip cap includes a plurality of walls defining a compartment which, if desired, can be divided into a plurality of subcompartments. The tip cap can include inlet and outlet holes in walls thereof to permit fluid communication of a cooling fluid there through. Abrasive material can be attached with the radially outer wall of the tip cap.

  11. Numerical Simulation of Three-Dimensional Dendritic Growth of Alloy: Part I—Model Development and Test

    NASA Astrophysics Data System (ADS)

    Wang, Weiling; Luo, Sen; Zhu, Miaoyong

    2016-03-01

    To improve the computational efficiency of the three-dimensional (3D) cellular-automaton-finite-volume-method (CA-FVM) model for describing the dendritic growth of alloy, the block-correction technique (BCT) and the parallel computation approach are introduced. Accordingly, a serial of investigations on the efficiency of the optimized codes in dealing with the designed cases for the melt flow and the heat transfer problems is carried out. Moreover, the accuracy of the present codes is evaluated by the comparisons between the solution to the melt flow and the heat transfer problems and the results from analytical equations and the commercial software. Additionally, the capability of the present CA model is evaluated by comparing the steady growth parameters of the equiaxed dendritic tip and the morphology and the secondary dendrite arm spacing (SDAS) of columnar dendrites with the LGK analytical model and the experimental results of the unidirectional solidification of high-carbon steels. The results show that with the introduction of the 3D BCT, the iteration process of the serial tri-diagonal matrix algorithm (TDMA) code changes from the fluctuation type to the smooth one, and thus, the computational cost is reduced significantly. Moreover, the parallel Jacobi code with one two-dimensional (2D) iteration in 3D BCT is proved to be the most efficient one among the codes compiled in the present work, and therefore, accordingly it is employed to simulate the 3D dendritic growth of alloys. The calculated velocity distribution and temperature variation agree well with the results from the analytical equations and the commercial software. The predicted steady tip velocities agree with the LGK analytical model as the undercooling is 6 K to 7 K. Moreover, the predicted columnar dendritic morphology and SDAS of high-carbon Fe-C alloys during the unidirectional solidification agree with the experimental results.

  12. British Columbia Transfer TIPS: Facilitation Guide.

    ERIC Educational Resources Information Center

    British Columbia Council on Admissions and Transfer, Vancouver.

    This document is a guide for teachers, career counselors, community practitioners, and students to navigate the British Columbia (BC) Transfer TIPS (transfer information for post-secondary success), a handbook for students intending to transfer among institutions listed in the BC Transfer TIPS. Specifically, the BC Transfer TIPS is intended…

  13. Injector tip for an internal combustion engine

    DOEpatents

    Shyu, Tsu Pin; Ye, Wen

    2003-05-20

    This invention relates to a the tip structure of a fuel injector as used in a internal combustion engine. Internal combustion engines using Homogeneous Charge Compression Ignition (HCCI) technology require a tip structure that directs fuel spray in a downward direction. This requirement necessitates a tip design that is capable of withstanding mechanical stresses associated with the design.

  14. A localized multimeric anchor attaches the Caulobacter holdfast to the cell pole

    PubMed Central

    Hardy, Gail G.; Allen, Rebecca C.; Toh, Evelyn; Long, Maria; Brown, Pamela J. B.; Cole-Tobian, Jennifer L.; Brun, Yves V.

    2010-01-01

    Summary Caulobacter crescentus attachment is mediated by the holdfast, a complex of polysaccharide anchored to the cell by HfaA, HfaB and HfaD. We show that all three proteins are surface-exposed outer membrane (OM) proteins. HfaA is similar to fimbrial proteins and assembles into a high molecular weight (HMW) form requiring HfaD, but not holdfast polysaccharide. The HfaD HMW form is dependent on HfaA but not on holdfast polysaccharide. We show that HfaA and HfaD form homomultimers and that they require HfaB for stability and OM translocation. All three proteins localize to the late predivisional flagellar pole, remain at this pole in swarmer cells, and localize at the stalk tip after the stalk is synthesized at the same pole. Hfa protein localization requires the holdfast polysaccharide secretion proteins and the polar localization factor PodJ. A hfaB mutant is much more severely deficient in adherence and holdfast attachment than hfaA and hfaD mutants. A hfaA, hfaD double mutant phenocopies either single mutant, suggesting that HfaB is involved in holdfast attachment beyond secretion of HfaA and HfaD. We hypothesize HfaB secretes HfaA and HfaD across the outer membrane, and the three proteins form a complex anchoring the holdfast to the stalk. PMID:20233308

  15. Influence of diffusion and convective transport on dendritic growth in dilute alloys

    NASA Technical Reports Server (NTRS)

    Glicksman, M. E.; Singh, N. B.; Chopra, M.

    1982-01-01

    Experimentation has been carried out in which the kinetics and morphology of dendritic growth were measured as a function of thermal supercooling, solute concentration, and spatial orientation of the dendritic growth axis. The crystal growth system studied is succinonitrile, NC(CH2)2CN, with additions of argon (up to 0.1 mole percent). This system is especially useful as a model for alloy studies because kinetic data are available for high purity (7-9's) succinonitrile. The influence of the solute, at fixed thermal supercooling, is to increase the growth velocity and correspondingly decrease intrinsic crystal dimensions. Morphological measurements are described in detail relating tip size, perturbation wavelength, supercooling, and solute concentration. The analysis of these effects based on morphological stability theory is also discussed, and experiments permitting the separation of convective and diffusive heat transport during crystal growth of succinonitrile are described. The studies underscore the importance of gravitationally-induced buoyancy effects on crystal growth.

  16. Astronaut Akers with TIPS messages

    NASA Image and Video Library

    1996-09-22

    STS79-E-5246 (22 September 1996) --- Astronauts Thomas D. Akers and Shannon W. Lucid check the latest send-up of "mail" on the Space Shuttle Atlantis' mid deck, during Flight Day 7. The Thermal Imaging Printing System (TIPS) messages likely include information pertinent to the final day of joint activities with the Mir-22 crew members whom Lucid will leave behind for her return to Earth later this week.

  17. Adapting Roof Support Methods for Anchoring Satellites on Asteroids

    NASA Astrophysics Data System (ADS)

    Speer, Grant B.

    The use of anchorage in satellite and spacecraft design has been largely restricted to harpoon-inspired technology based on anticipated low strengths of cometary and asteroid material. Initial results from the Rosetta mission to comet 67P/Churyumov- Gerasimenko, however, have demonstrated both larger-than-expected compressive strengths of cometary materials and the importance of adequate anchorage to mitigate the risk of mission failure. The field of rock mechanics can provide unique insight into the design of these satellite and lander anchors by drawing on existing roof bolt technology. This study compared the behavior of tensioned point anchor and untensioned fully-grouted roof bolts with a polyurethane-anchored bolt under environmental conditions similar to those anticipated in space. These conditions include variation in possible material types as well as variations in regolith properties, anchorage length, and low operating temperatures. Using a Box-Behnken experimental design, this study first compared the effects of anchor depth and rock strength on each of the three anchorage types in a competent rock strength regime. The study then examined the effects of compaction, water content, and temperature on each anchor type in a regolith environment. The subsequent data analysis identified one anchor type as the overall best anchor for these environments. This finding has led to a preliminary design recommendation to advise space agencies on satellite anchor construction based on the target orbital body's anticipated environmental and "exogeologic" conditions.

  18. Using Anchored Instruction to Evaluate Mathematical Growth and Understanding

    ERIC Educational Resources Information Center

    Kurz, Terri L.; Batarelo, Ivana

    2005-01-01

    Anchored instruction is designed to present problems in a meaningful context to allow for investigations into real life environments. The Jasper Project was created to allow students to investigate mathematical dilemmas using anchored instruction techniques. This study uses case study methods to examine the perceptions that preservice teachers…

  19. 24 CFR 3285.402 - Ground anchor installations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... HOUSING AND URBAN DEVELOPMENT MODEL MANUFACTURED HOME INSTALLATION STANDARDS Anchorage Against Wind § 3285... anchoring. Manufactured homes must also be stabilized against wind in the longitudinal direction in all Wind Zones. Manufactured homes located in Wind Zones II and III must have longitudinal ground anchors...

  20. Retention of internal anchor tags by juvenile striped bass

    USGS Publications Warehouse

    Van Den Avyle, M.J.; Wallin, J.E.

    2001-01-01

    We marked hatchery-reared striped bass Morone saxatilis (145-265 mm total length) with internal anchor tags and monitored retention for 28 months after stocking in the Savannah River, Georgia and South Carolina. Anchor tags (with an 18-mm, T-shaped anchor and 42-mm streamer) were surgically implanted ventrally, and coded wire tags (1 mm long and 0.25 mm in diameter) were placed into the cheek muscle to help identify subsequent recaptures. The estimated probability of retention (SD) of anchor tags was 0.94 (0.05) at 4 months, 0.64 (0.13) at 16 months, and 0.33 (0.19) at 28 months. Of 10 fish recaptured with only coded wire tags, 5 showed an externally visible wound or scar near the point of anchor tag insertion. The incidence of wounds or scars, which we interpreted as evidence of tag shedding, increased to 50% in recaptures taken at 28 months (three of six fish). Our estimates for retention of anchor tags were generally lower than those in other studies of striped bass, possibly because of differences in the style of anchor or sizes of fish used. Because of its low rate of retention, the type of anchor tag we used may not be suitable for long-term assessments of stock enhancement programs that use striped bass of the sizes we evaluated.

  1. 30 CFR 56.9311 - Anchoring stationary sizing devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Anchoring stationary sizing devices. 56.9311 Section 56.9311 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Dumping Sites § 56.9311 Anchoring stationary sizing devices. Grizzlies and other stationary sizing devices...

  2. 107. View showing open caisson Pier 4 with anchor bolts ...

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

    107. View showing open caisson Pier 4 with anchor bolts placed ready for last pour of concrete. Also pile driver driving falsework piles for south anchor arm. Located at end of the old ferry landing slip at Crockett side of straits. - Carquinez Bridge, Spanning Carquinez Strait at Interstate 80, Vallejo, Solano County, CA

  3. 49 CFR 178.337-13 - Supporting and anchoring.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Supporting and anchoring. 178.337-13 Section 178.337-13 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS... Specifications for Containers for Motor Vehicle Transportation § 178.337-13 Supporting and anchoring. (a) A cargo...

  4. 30 CFR 56.9311 - Anchoring stationary sizing devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Anchoring stationary sizing devices. 56.9311 Section 56.9311 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Dumping Sites § 56.9311 Anchoring stationary sizing devices. Grizzlies and other stationary sizing devices...

  5. 49 CFR 178.337-13 - Supporting and anchoring.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Supporting and anchoring. 178.337-13 Section 178.337-13 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS... Specifications for Containers for Motor Vehicle Transportation § 178.337-13 Supporting and anchoring. (a) A cargo...

  6. 30 CFR 57.9311 - Anchoring stationary sizing devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Anchoring stationary sizing devices. 57.9311 Section 57.9311 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Dumping Sites § 57.9311 Anchoring stationary sizing devices. Grizzlies and other stationary sizing devices...

  7. 30 CFR 57.9311 - Anchoring stationary sizing devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Anchoring stationary sizing devices. 57.9311 Section 57.9311 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Dumping Sites § 57.9311 Anchoring stationary sizing devices. Grizzlies and other stationary sizing devices...

  8. 49 CFR 178.345-6 - Supports and anchoring.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Supports and anchoring. 178.345-6 Section 178.345-6 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS... Specifications for Containers for Motor Vehicle Transportation § 178.345-6 Supports and anchoring. (a) A cargo...

  9. 30 CFR 56.9311 - Anchoring stationary sizing devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Anchoring stationary sizing devices. 56.9311 Section 56.9311 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Dumping Sites § 56.9311 Anchoring stationary sizing devices. Grizzlies and other stationary sizing devices...

  10. 30 CFR 57.9311 - Anchoring stationary sizing devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Anchoring stationary sizing devices. 57.9311 Section 57.9311 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Dumping Sites § 57.9311 Anchoring stationary sizing devices. Grizzlies and other stationary sizing devices...

  11. Anchoring on Self and Others During Social Inferences.

    PubMed

    Willard, Daniel F X; Markman, Arthur B

    2017-07-01

    When making inferences about similar others, people anchor and adjust away from themselves (Tamir & Mitchell, 2013). However, research on relational self theory (Andersen & Chen, 2002) suggests the possibility of using knowledge about others as an anchor when they are more similar to a target. We investigated whether social inferences are made on the basis of significant other knowledge through an anchoring and adjustment process, and whether anchoring on a significant other is more effortful than anchoring on the self. Participants answered questions about their likes and habits, as well as the likes and habits of a significant other, a target similar to their significant other, and a yoked control. We found that prediction differences between the significant other and similar target led to longer response times, and we found the opposite effect for self and target differences, suggesting anchoring and adjustment from the significant other rather than the self. These effects were moderated by the source-relative salience of the dimension being evaluated. The evidence was mixed with respect to the question of whether anchoring on a significant other is more effortful than anchoring on the self. Copyright © 2017 Cognitive Science Society, Inc.

  12. 30 CFR 57.9311 - Anchoring stationary sizing devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Anchoring stationary sizing devices. 57.9311 Section 57.9311 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Dumping Sites § 57.9311 Anchoring stationary sizing devices. Grizzlies and other stationary sizing devices...

  13. 49 CFR 178.345-6 - Supports and anchoring.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Supports and anchoring. 178.345-6 Section 178.345-6 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS... Specifications for Containers for Motor Vehicle Transportation § 178.345-6 Supports and anchoring. (a) A cargo...

  14. 49 CFR 178.337-13 - Supporting and anchoring.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Supporting and anchoring. 178.337-13 Section 178.337-13 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS... Specifications for Containers for Motor Vehicle Transportation § 178.337-13 Supporting and anchoring. (a) A cargo...

  15. 49 CFR 178.337-13 - Supporting and anchoring.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Supporting and anchoring. 178.337-13 Section 178.337-13 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS... Specifications for Containers for Motor Vehicle Transportation § 178.337-13 Supporting and anchoring. (a) A cargo...

  16. 30 CFR 57.9311 - Anchoring stationary sizing devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Anchoring stationary sizing devices. 57.9311 Section 57.9311 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Dumping Sites § 57.9311 Anchoring stationary sizing devices. Grizzlies and other stationary sizing devices...

  17. 30 CFR 56.9311 - Anchoring stationary sizing devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Anchoring stationary sizing devices. 56.9311 Section 56.9311 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Dumping Sites § 56.9311 Anchoring stationary sizing devices. Grizzlies and other stationary sizing devices...

  18. 30 CFR 56.9311 - Anchoring stationary sizing devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Anchoring stationary sizing devices. 56.9311 Section 56.9311 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Dumping Sites § 56.9311 Anchoring stationary sizing devices. Grizzlies and other stationary sizing devices...

  19. Software Note: Using BILOG for Fixed-Anchor Item Calibration

    ERIC Educational Resources Information Center

    DeMars, Christine E.; Jurich, Daniel P.

    2012-01-01

    The nonequivalent groups anchor test (NEAT) design is often used to scale item parameters from two different test forms. A subset of items, called the anchor items or common items, are administered as part of both test forms. These items are used to adjust the item calibrations for any differences in the ability distributions of the groups taking…

  20. The Critical Role of Anchor Paper Selection in Writing Assessment

    ERIC Educational Resources Information Center

    Osborn Popp, Sharon E.; Ryan, Joseph M.; Thompson, Marilyn S.

    2009-01-01

    Scoring rubrics are routinely used to evaluate the quality of writing samples produced for writing performance assessments, with anchor papers chosen to represent score points defined in the rubric. Although the careful selection of anchor papers is associated with best practices for scoring, little research has been conducted on the role of…

  1. Understanding Rasch Measurement: Partial Credit Model and Pivot Anchoring.

    ERIC Educational Resources Information Center

    Bode, Rita K.

    2001-01-01

    Describes the Rasch measurement partial credit model, what it is, how it differs from other Rasch models, and when and how to use it. Also describes the calibration of instruments with increasingly complex items. Explains pivot anchoring and illustrates its use and describes the effect of pivot anchoring on step calibrations, item hierarchy, and…

  2. Using Anchored Instruction to Evaluate Mathematical Growth and Understanding

    ERIC Educational Resources Information Center

    Kurz, Terri L.; Batarelo, Ivana

    2005-01-01

    Anchored instruction is designed to present problems in a meaningful context to allow for investigations into real life environments. The Jasper Project was created to allow students to investigate mathematical dilemmas using anchored instruction techniques. This study uses case study methods to examine the perceptions that preservice teachers…

  3. 33 CFR 401.14 - Anchor marking buoys.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Anchor marking buoys. 401.14 Section 401.14 Navigation and Navigable Waters SAINT LAWRENCE SEAWAY DEVELOPMENT CORPORATION, DEPARTMENT OF TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Condition of Vessels § 401.14 Anchor...

  4. Electrically insulated MLI and thermal anchor

    SciTech Connect

    Kamiya, Koji; Furukawa, Masato; Murakami, Haruyuki; Kizu, Kaname; Tsuchiya, Katsuhiko; Koidea, Yoshihiko; Yoshida, Kiyoshi; Hatakenaka, Ryuta; Miyakita, Takeshi

    2014-01-29

    The thermal shield of JT-60SA is kept at 80 K and will use the multilayer insulation (MLI) to reduce radiation heat load to the superconducting coils at 4.4 K from the cryostat at 300 K. Due to plasma pulse operation, the MLI is affected by eddy current in toroidal direction. The MLI is designed to suppress the current by electrically insulating every 20 degree in the toroidal direction by covering the MLI with polyimide films. In this paper, two kinds of designs for the MLI system are proposed, focusing on a way to overlap the layers. A boil-off calorimeter method and temperature measurement has been performed to determine the thermal performance of the MLI system. The design of the electrical insulated thermal anchor between the toroidal field (TF) coil and the thermal shield is also explained.

  5. In vivo dendrite regeneration after injury is different from dendrite development

    PubMed Central

    Li, Tun; Jan, Lily Yeh; Jan, Yuh Nung

    2016-01-01

    Neurons receive information along dendrites and send signals along axons to synaptic contacts. The factors that control axon regeneration have been examined in many systems, but dendrite regeneration has been largely unexplored. Here we report that, in intact Drosophila larvae, a discrete injury that removes all dendrites induces robust dendritic growth that recreates many features of uninjured dendrites, including the number of dendrite branches that regenerate and responsiveness to sensory stimuli. However, the growth and patterning of injury-induced dendrites is significantly different from uninjured dendrites. We found that regenerated arbors cover much less territory than uninjured neurons, fail to avoid crossing over other branches from the same neuron, respond less strongly to mechanical stimuli, and are pruned precociously. Finally, silencing the electrical activity of the neurons specifically blocks injury-induced, but not developmental, dendrite growth. By elucidating the essential features of dendrites grown in response to acute injury, our work builds a framework for exploring dendrite regeneration in physiological and pathological conditions. PMID:27542831

  6. In vivo dendrite regeneration after injury is different from dendrite development.

    PubMed

    Thompson-Peer, Katherine L; DeVault, Laura; Li, Tun; Jan, Lily Yeh; Jan, Yuh Nung

    2016-08-01

    Neurons receive information along dendrites and send signals along axons to synaptic contacts. The factors that control axon regeneration have been examined in many systems, but dendrite regeneration has been largely unexplored. Here we report that, in intact Drosophila larvae, a discrete injury that removes all dendrites induces robust dendritic growth that recreates many features of uninjured dendrites, including the number of dendrite branches that regenerate and responsiveness to sensory stimuli. However, the growth and patterning of injury-induced dendrites is significantly different from uninjured dendrites. We found that regenerated arbors cover much less territory than uninjured neurons, fail to avoid crossing over other branches from the same neuron, respond less strongly to mechanical stimuli, and are pruned precociously. Finally, silencing the electrical activity of the neurons specifically blocks injury-induced, but not developmental, dendrite growth. By elucidating the essential features of dendrites grown in response to acute injury, our work builds a framework for exploring dendrite regeneration in physiological and pathological conditions.

  7. Dendritic Growth in Undercooled Melts

    NASA Technical Reports Server (NTRS)

    Glicksman, M. E.

    1985-01-01

    The kinetic and morphological behavior of systems solidifying at small undercooling were investigated with emphasis on the role of convective and diffusive transport and the influence of gravity. A data base was established for pure succinonitrile which permits a comprehensive check on diffusional dendrite growth theory and the development of scaling laws to extend the theory to other material systems. A departure from diffusional-controlled growth was observed which becomes more significant at smaller undercoolings. A shuttle experiment is prepared to test the theory at the low undercoolings where convective effects begin to dominate.

  8. [Disseminated interdigitating dendritic cell sarcoma].

    PubMed

    Santarelli, Ignacio M; Veltri, Mariano; Manzella, Diego J; Avagnina, María Alejandra; Pereyra, Pablo M; Chavín, Hernán C

    2017-01-01

    A 70 year-old woman was admitted to our hospital with a 3-month history of abdominal pain, weight loss and night sweats. On physical examination, she presented with a 5 cm diameter abdominal mass extended from epigastrium to the left flank, and at least three bilateral supraclavicular adenopathies. A disseminated interdigitating dendritic cell sarcoma was diagnosed through a biopsy of the abdominal mass. After that, a CHOP regime (cyclophosphamide, doxorubicin, vincristine and prednisone) was iniciated. She died after completion of the first cycle of treatment, six months after diagnosis.

  9. Coated fiber tips for optical instrumentation

    NASA Astrophysics Data System (ADS)

    Barton, John B.; Chanda, Sheetal; Locknar, Sarah A.; Carver, Gary E.

    2016-03-01

    Compact optical systems can be fabricated by integrating coatings on fiber tips. Examples include fiber lasers, fiber interferometers, fiber Raman probes, fiber based spectrometers, and anti-reflected endoscopes. These interference filters are applied to exposed tips - either connectorized or cleaved. Coatings can also be immersed within glass by depositing on one tip and connecting to another uncoated tip. This paper addresses a fiber spectrometer for multispectral imaging - useful in several fields including biomedical scanning, flow cytometry, and remote sensing. Our spectrometer integrates serial arrays of reflecting fiber tips, delay lines between these elements, and a single element detector.

  10. Anchoring submersible ultrasonic receivers in river channels with stable substrate

    USGS Publications Warehouse

    Bettoli, Phillip William; Scholten, G.D.; Hubbs, D.

    2010-01-01

    We developed an anchoring system for submersible ultrasonic receivers (SURs) that we placed on the bottom of the riverine reaches of three main-stem reservoirs in the upper Tennessee River. Each anchor consisted of a steel tube (8.9 x 35.6 cm) welded vertically to a round plate of steel (5.1 x 40.6 cm). All seven SURs and their 57-kg anchors were successfully deployed and retrieved three times over 547 d by a dive team employing surface air-breathing equipment and a davit-equipped boat. All of the anchors and their SURs remained stationary over two consecutive winters on the hard-bottom, thalweg sites where they were deployed. The SUR and its anchor at the most downriver site experienced flows that exceeded 2,100 m(3)/s and mean water column velocities of about 0.9 m/s.

  11. Lung dendritic cells and the inflammatory response.

    PubMed

    Grayson, Mitchell H

    2006-05-01

    To discuss the role of conventional and plasmacytoid dendritic cells in inducing and modulating immune responses in the lung. The primary literature and selected review articles studying the role of dendritic cells in both rodent and human lungs as identified via a PubMed/MEDLINE search using the keywords dendritic cell, antigen-presenting cell, viral airway disease, asthma, allergy, and atopy. The author's knowledge of the field was used to identify studies that were relevant to the stated objective. Dendritic cells are well positioned in the respiratory tract and other mucosal surfaces to respond to any foreign protein. These cells are crucial to the initiation of the adaptive immune response through induction of antigen specific T-cell responses. These cells also play an important role in the regulation of developing and ongoing immune responses, an area that is currently under intense investigation. This review discusses the various subsets of human and rodent dendritic cells and the pathways involved in antigen processing and subsequent immune regulation by dendritic cells in the lung using both viral and nonviral allergenic protein exposure as examples. Conventional and plasmacytoid dendritic cells are uniquely situated in the immune cascade to not only initiate but also modulate immune responses. Therapeutic interventions in allergic and asthmatic diseases will likely be developed to take advantage of this exclusive position of the dendritic cell.

  12. Effects of accuracy motivation and anchoring on metacomprehension judgment and accuracy.

    PubMed

    Zhao, Qin

    2012-01-01

    The current research investigates how accuracy motivation impacts anchoring and adjustment in metacomprehension judgment and how accuracy motivation and anchoring affect metacomprehension accuracy. Participants were randomly assigned to one of six conditions produced by the between-subjects factorial design involving accuracy motivation (incentive or no) and peer performance anchor (95%, 55%, or no). Two studies showed that accuracy motivation did not impact anchoring bias, but the adjustment-from-anchor process occurred. Accuracy incentive increased anchor-judgment gap for the 95% anchor but not for the 55% anchor, which induced less certainty about the direction of adjustment. The findings offer support to the integrative theory of anchoring. Additionally, the two studies revealed a "power struggle" between accuracy motivation and anchoring in influencing metacomprehension accuracy. Accuracy motivation could improve metacomprehension accuracy in spite of anchoring effect, but if anchoring effect is too strong, it could overpower the motivation effect. The implications of the findings were discussed.

  13. Advanced turbine blade tip seal system

    NASA Technical Reports Server (NTRS)

    Zelahy, J. W.

    1981-01-01

    An advanced blade/shroud system designed to maintain close clearance between blade tips and turbine shrouds and at the same time, be resistant to environmental effects including high temperature oxidation, hot corrosion, and thermal cycling is described. Increased efficiency and increased blade life are attained by using the advanced blade tip seal system. Features of the system include improved clearance control when blade tips preferentially wear the shrouds and a superior single crystal superalloy tip. The tip design, joint location, characterization of the single crystal tip alloy, the abrasive tip treatment, and the component and engine test are among the factors addressed. Results of wear testing, quality control plans, and the total manufacturing cycle required to fully process the blades are also discussed.

  14. Parametric tip effects for conformable rotor applications

    NASA Technical Reports Server (NTRS)

    Mantay, W. R.; Yeager, W. T., Jr.

    1983-01-01

    A research study was initiated to systematically determine the impact of selected blade tip geometric parameters on aeroelasticity conformable rotor performance and loads characteristics. The model articulated rotors included baseline and torsionally soft blades with interchangeable tips. Seven blade tip designs were evaluated on the baseline rotor and three tip designs were tested on the torsionally soft blades. The designs incorporated a systematic variation in three geometric parameters: sweep, taper, and anhedral. The rotors were evaluated in the NASA Langley Transonic Dynamics Tunnel at several advance ratios, lift and propulsive force values, and tip Mach numbers. Based on the test results, tip parameter variations generated significant rotor performance and loads difference for both baseline and torsionally soft blades. Azimuthal variation of elastic twist generated by the tip parameters strongly correlated with rotor performance and loads, but the magnitude of advancing blade elastic twist did not correlate.

  15. Convection and diffusion effects during dendritic solidification

    NASA Technical Reports Server (NTRS)

    Glicksman, M. E.; Huang, S.-C.

    1979-01-01

    A report is presented of the first quantitative measurements of dendritic growth at supercooling levels where convection instead of diffusion is the controlling heat transfer mechanism. Precautions similar to that used in an investigation conducted by Glicksman et al. (1976) were taken to insure 'free' dendritic growth conditions. Dendritic growth velocity was measured as a function of growth orientation at seventeen supercoolings which ranged from 0.043 C to 2 C. Selected but representative measurements of velocity versus orientation angle are shown in a graph. The relative growth velocity of a downward growing dendrite is found to be greater than that of a diffusion-limited dendrite. This result is consistent with that expected from the enhanced heat transfer arising from natural convection.

  16. Isolation and generation of human dendritic cells.

    PubMed

    Nair, Smita; Archer, Gerald E; Tedder, Thomas F

    2012-11-01

    Dendritic cells are highly specialized antigen-presenting cells (APC), which may be isolated or generated from human blood mononuclear cells. Although mature blood dendritic cells normally represent ∼0.2% of human blood mononuclear cells, their frequency can be greatly increased using the cell enrichment methods described in this unit. More highly purified dendritic cell preparations can be obtained from these populations by sorting of fluorescence-labeled cells. Alternatively, dendritic cells can be generated from monocytes by culture with the appropriate cytokines, as described here. In addition, a negative selection approach is provided that may be employed to generate cell preparations that have been depleted of dendritic cells to be used for comparison in functional studies.

  17. The plunging tip: analysis and surgical treatment.

    PubMed

    Kosins, Aaron M; Lambros, Val; Daniel, Rollin K

    2015-05-01

    The plunging tip refers to a deformity in which the nasal tip plunges on smiling. To understand the plunging tip, we have updated our series of 25 cosmetic rhinoplasty patients who complained of a plunging tip with a focus on the anatomic changes of the nose on smiling. Twenty-five female cosmetic primary rhinoplasty patients who complained of a nasal tip that plunged on smiling were photographed in static and smiling sequences preoperatively and one year postoperatively. Different nasal angles and landmarks were measured to study changes of the nose. Pre- and postoperatively, there was no statistically significant difference in the changes in the nasal angles and landmarks on smiling. At one year postoperatively, 2 patients had nasal tips that continued to plunge on smiling; these patients had requested no increase in tip rotation preoperatively. Only 2 patients had columellar base muscles cut for reasons other than treating the plunging tip. This is the first prospective, evidence-based study on the plunging tip. Measurements of the nose before and after surgery demonstrate that the nasal tip moves less than 1 mm and 1 degree on smiling. Treatment of the plunging tip illusion was effective by increasing the tip angle in repose. No columellar base muscles were cut to treat the plunging tip, and the nose moved just as much after surgery as before. Cutting or manipulating muscles is not necessary for treatment. To treat the illusion, the surgeon must increase tip rotation. © 2015 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

  18. Aspergillus nidulans ChiA is a glycosylphosphatidylinositol (GPI)-anchored chitinase specifically localized at polarized growth sites.

    PubMed

    Yamazaki, Harutake; Tanaka, Aya; Kaneko, Jun-ichi; Ohta, Akinori; Horiuchi, Hiroyuki

    2008-06-01

    It is believed that chitinases play important physiological roles in filamentous fungi since chitin is one of the major cell wall components in these organisms. In this paper we investigated a chitinase gene, chiA, of Aspergillus nidulans and found that the gene product of chiA consists of a signal sequence, a region including chitinase consensus motifs, a Ser/Thr/Pro-rich region and a glycosylphosphatidylinositol (GPI)-anchor attachment motif. Phosphatidylinositol-specific phospholipase C treatment of the fusion protein of ChiA and enhanced green fluorescent protein (EGFP)-ChiA-EGFP-caused a change in its hydrophobicity, indicating that ChiA is a GPI-anchored protein. ChiA-EGFP localized at the germ tubes of conidia, at hyphal branching sites and hyphal tips. chiA expression was specifically high during conidia germination and in the marginal growth regions of colonies. These results suggest that ChiA functions as a GPI-anchored chitinase at the sites where cell wall remodeling and/or cell wall maturation actively take place.

  19. Active dendrites, potassium channels and synaptic plasticity.

    PubMed Central

    Johnston, Daniel; Christie, Brian R; Frick, Andreas; Gray, Richard; Hoffman, Dax A; Schexnayder, Lalania K; Watanabe, Shigeo; Yuan, Li-Lian

    2003-01-01

    The dendrites of CA1 pyramidal neurons in the hippocampus express numerous types of voltage-gated ion channel, but the distributions or densities of many of these channels are very non-uniform. Sodium channels in the dendrites are responsible for action potential (AP) propagation from the axon into the dendrites (back-propagation); calcium channels are responsible for local changes in dendritic calcium concentrations following back-propagating APs and synaptic potentials; and potassium channels help regulate overall dendritic excitability. Several lines of evidence are presented here to suggest that back-propagating APs, when coincident with excitatory synaptic input, can lead to the induction of either long-term depression (LTD) or long-term potentiation (LTP). The induction of LTD or LTP is correlated with the magnitude of the rise in intracellular calcium. When brief bursts of synaptic potentials are paired with postsynaptic APs in a theta-burst pairing paradigm, the induction of LTP is dependent on the invasion of the AP into the dendritic tree. The amplitude of the AP in the dendrites is dependent, in part, on the activity of a transient, A-type potassium channel that is expressed at high density in the dendrites and correlates with the induction of the LTP. Furthermore, during the expression phase of the LTP, there are local changes in dendritic excitability that may result from modulation of the functioning of this transient potassium channel. The results support the view that the active properties of dendrites play important roles in synaptic integration and synaptic plasticity of these neurons. PMID:12740112

  20. Degenerate seaweed to tilted dendrite transition and their growth dynamics in directional solidification of non-axially oriented crystals: a phase-field study

    NASA Astrophysics Data System (ADS)

    Xing, Hui; Dong, Xianglei; Wu, Hongjing; Hao, Guanhua; Wang, Jianyuan; Chen, Changle; Jin, Kexin

    2016-05-01

    We report the results of a phase-field study of degenerate seaweed to tilted dendrite transition and their growth dynamics during directional solidification of a binary alloy. Morphological selection maps in the planes of (G, Vp) and (ε4, Vp) show that lower pulling velocity, weaker anisotropic strength and higher thermal gradient can enhance the formation of the degenerate seaweed. The tip undercooling shows oscillations in seaweed growth, but it keeps at a constant value in dendritic growth. The M-S instability on the tips and the surface tension anisotropy of the solid-liquid interface are responsible for the formation of the degenerate seaweed. It is evidenced that the place where the interfacial instability occurs determines the morphological transition. The transient transition from degenerate seaweed to tilted dendrite shows that dendrites are dynamically preferred over seaweed. For the tilted dendritic arrays with a large tilted angle, primary spacing is investigated by comparing predicted results with the classical scaling power law, and the growth direction is found to be less sensitive to the pulling velocity and the primary spacing. Furthermore, the effect of the initial interface wavelength on the morphological transition is investigated to perform the history dependence of morphological selection.