Coevolved Mutations Reveal Distinct Architectures for Two Core Proteins in the Bacterial Flagellar Motor

PubMed Central

Pandini, Alessandro; Kleinjung, Jens; Rasool, Shafqat; Khan, Shahid

2015-01-01

Switching of bacterial flagellar rotation is caused by large domain movements of the FliG protein triggered by binding of the signal protein CheY to FliM. FliG and FliM form adjacent multi-subunit arrays within the basal body C-ring. The movements alter the interaction of the FliG C-terminal (FliGC) “torque” helix with the stator complexes. Atomic models based on the Salmonella entrovar C-ring electron microscopy reconstruction have implications for switching, but lack consensus on the relative locations of the FliG armadillo (ARM) domains (amino-terminal (FliGN), middle (FliGM) and FliGC) as well as changes during chemotaxis. The generality of the Salmonella model is challenged by the variation in motor morphology and response between species. We studied coevolved residue mutations to determine the unifying elements of switch architecture. Residue interactions, measured by their coevolution, were formalized as a network, guided by structural data. Our measurements reveal a common design with dedicated switch and motor modules. The FliM middle domain (FliMM) has extensive connectivity most simply explained by conserved intra and inter-subunit contacts. In contrast, FliG has patchy, complex architecture. Conserved structural motifs form interacting nodes in the coevolution network that wire FliMM to the FliGC C-terminal, four-helix motor module (C3-6). FliG C3-6 coevolution is organized around the torque helix, differently from other ARM domains. The nodes form separated, surface-proximal patches that are targeted by deleterious mutations as in other allosteric systems. The dominant node is formed by the EHPQ motif at the FliMMFliGM contact interface and adjacent helix residues at a central location within FliGM. The node interacts with nodes in the N-terminal FliGc α-helix triad (ARM-C) and FliGN. ARM-C, separated from C3-6 by the MFVF motif, has poor intra-network connectivity consistent with its variable orientation revealed by structural data. ARM-C could be the convertor element that provides mechanistic and species diversity. PMID:26561852

The structure of TON1937 from archaeon Thermococcus onnurineus NA1 reveals a eukaryotic HEAT-like architecture.

PubMed

Jeong, Jae-Hee; Kim, Yi-Seul; Rojviriya, Catleya; Cha, Hyung Jin; Ha, Sung-Chul; Kim, Yeon-Gil

2013-10-01

The members of the ARM/HEAT repeat-containing protein superfamily in eukaryotes have been known to mediate protein-protein interactions by using their concave surface. However, little is known about the ARM/HEAT repeat proteins in prokaryotes. Here we report the crystal structure of TON1937, a hypothetical protein from the hyperthermophilic archaeon Thermococcus onnurineus NA1. The structure reveals a crescent-shaped molecule composed of a double layer of α-helices with seven anti-parallel α-helical repeats. A structure-based sequence alignment of the α-helical repeats identified a conserved pattern of hydrophobic or aliphatic residues reminiscent of the consensus sequence of eukaryotic HEAT repeats. The individual repeats of TON1937 also share high structural similarity with the canonical eukaryotic HEAT repeats. In addition, the concave surface of TON1937 is proposed to be its potential binding interface based on this structural comparison and its surface properties. These observations lead us to speculate that the archaeal HEAT-like repeats of TON1937 have evolved to engage in protein-protein interactions in the same manner as eukaryotic HEAT repeats. Copyright © 2013 Elsevier B.V. All rights reserved.

A numerical investigation of flow around octopus-like arms: near-wake vortex patterns and force development.

PubMed

Kazakidi, A; Vavourakis, V; Tsakiris, D P; Ekaterinaris, J A

2015-01-01

The fluid dynamics of cephalopods has so far received little attention in the literature, due to their complexity in structure and locomotion. The flow around octopuses, in particular, can be complicated due to their agile and dexterous arms, which frequently display some of the most diverse mechanisms of motion. The study of this flow amounts to a specific instance of the hydrodynamics problem for rough tapered cylinder geometries. The outstanding manipulative and locomotor skills of octopuses could inspire the development of advanced robotic arms, able to operate in fluid environments. Our primary aim was to study the hydrodynamic characteristics of such bio-inspired robotic models and to derive the hydrodynamic force coefficients as a concise description of the vortical flow effects. Utilizing computational fluid dynamic methods, the coefficients were computed on realistic morphologies of octopus-like arm models undergoing prescribed solid-body movements; such motions occur in nature for short durations in time, e.g. during reaching movements and exploratory behaviors. Numerical simulations were performed on translating, impulsively rotating, and maneuvering arms, around which the flow field structures were investigated. The results reveal in detail the generation of complex vortical flow structures around the moving arms. Hydrodynamic forces acting on a translating arm depend on the angle of incidence; forces generated during impulsive rotations of the arms are independent of their exact morphology and the angle of rotation; periodic motions based on a slow recovery and a fast power stroke are able to produce considerable propulsive thrust while harmonic motions are not. Parts of these results have been employed in bio-inspired models of underwater robotic mechanisms. This investigation may further assist elucidating the hydrodynamics underlying aspects of octopus locomotion and exploratory behaviors.

Immunohistochemical localization of two types of choline acetyltransferase in neurons and sensory cells of the octopus arm.

PubMed

Sakaue, Yuko; Bellier, Jean-Pierre; Kimura, Shin; D'Este, Loredana; Takeuchi, Yoshihiro; Kimura, Hiroshi

2014-01-01

Cholinergic structures in the arm of the cephalopod Octopus vulgaris were studied by immunohistochemistry using specific antisera for two types (common and peripheral) of acetylcholine synthetic enzyme choline acetyltransferase (ChAT): antiserum raised against the rat common type ChAT (cChAT), which is cross-reactive with molluscan cChAT, and antiserum raised against the rat peripheral type ChAT (pChAT), which has been used to delineate peripheral cholinergic structures in vertebrates, but not previously in invertebrates. Western blot analysis of octopus extracts revealed a single pChAT-positive band, suggesting that pChAT antiserum is cross-reactive with an octopus counterpart of rat pChAT. In immunohistochemistry, only neuronal structures of the octopus arm were stained by cChAT and pChAT antisera, although the pattern of distribution clearly differed between the two antisera. cChAT-positive varicose nerve fibers were observed in both the cerebrobrachial tract and neuropil of the axial nerve cord, while pChAT-positive varicose fibers were detected only in the neuropil of the axial nerve cord. After epitope retrieval, pChAT-positive neuronal cells and their processes became visible in all ganglia of the arm, including the axial and intramuscular nerve cords, and in ganglia of suckers. Moreover, pChAT-positive structures also became detectable in nerve fibers connecting the different ganglia, in smooth nerve fibers among muscle layers and dermal connective tissues, and in sensory cells of the suckers. These results suggest that the octopus arm has two types of cholinergic nerves: cChAT-positive nerves from brain ganglia and pChAT-positive nerves that are intrinsic to the arm.

Evidence for a Nascent Rift in South Sudan: Westward Extension of the East African Rift System?

NASA Astrophysics Data System (ADS)

Maceira, M.; Van Wijk, J. W.; Coblentz, D. D.; Modrak, R. T.

2013-12-01

Joint inversion of seismic and gravity data of eastern Africa reveals a low seismic wave velocity arm stretching from the southern Main Ethiopian rift westward in an east-west direction that has not been noticed in earlier work. The zone of low velocities is located in the upper mantle and is not overlain by a known structural rift expression. We analyzed the local pattern of seismicity and the stresses in the African plate to interpret this low velocity arm. The zone of low velocities is located within the Central African Fold Belt, which dissects the northern and southern portions of the African continent. It is seismically active with small to intermediate sized earthquakes occurring in the crust. Seven earthquake solutions indicate (oblique) normal faulting and low-angle normal faulting with a NS to NNW-SSE opening direction, as well as strike-slip faulting. This pattern of deformation is typically associated with rifting. The present day stress field in northeastern Africa reveals a tensional state of stress at the location of the low velocity arm with an opening direction that corresponds to the earthquake data. We propose that the South Sudan low velocity zone and seismic center are part of an undeveloped, nascent rift arm. The arm stretches from the East African Rift system westward.

Molecular clouds and galactic spiral structure

NASA Technical Reports Server (NTRS)

Dame, T. M.

1984-01-01

Galactic CO line emission at 115 GHz was surveyed in order to study the distribution of molecular clouds in the inner galaxy. Comparison of this survey with similar H1 data reveals a detailed correlation with the most intense 21 cm features. To each of the classical 21 cm H1 spiral arms of the inner galaxy there corresponds a CO molecular arm which is generally more clearly defined and of higher contrast. A simple model is devised for the galactic distribution of molecular clouds. The modeling results suggest that molecular clouds are essentially transient objects, existing for 15 to 40 million years after their formation in a spiral arm, and are largely confined to spiral features about 300 pc wide.

Conformational Dynamics of Mechanically Compliant DNA Nanostructures from Coarse-Grained Molecular Dynamics Simulations.

PubMed

Shi, Ze; Castro, Carlos E; Arya, Gaurav

2017-05-23

Structural DNA nanotechnology, the assembly of rigid 3D structures of complex yet precise geometries, has recently been used to design dynamic, mechanically compliant nanostructures with tunable equilibrium conformations and conformational distributions. Here we use coarse-grained molecular dynamics simulations to provide insights into the conformational dynamics of a set of mechanically compliant DNA nanostructures-DNA hinges that use single-stranded DNA "springs" to tune the equilibrium conformation of a layered double-stranded DNA "joint" connecting two stiff "arms" constructed from DNA helix bundles. The simulations reproduce the experimentally measured equilibrium angles between hinge arms for a range of hinge designs. The hinges are found to be structurally stable, except for some fraying of the open ends of the DNA helices comprising the hinge arms and some loss of base-pairing interactions in the joint regions coinciding with the crossover junctions, especially in hinges designed to exhibit a small bending angle that exhibit large local stresses resulting in strong kinks in their joints. Principal component analysis reveals that while the hinge dynamics are dominated by bending motion, some twisting and sliding of hinge arms relative to each other also exists. Forced deformation of the hinges reveals distinct bending mechanisms for hinges with short, inextensible springs versus those with longer, more extensible springs. Lastly, we introduce an approach for rapidly predicting equilibrium hinge angles from individual force-deformation behaviors of its single- and double-stranded DNA components. Taken together, these results demonstrate that coarse-grained modeling is a promising approach for designing, predicting, and studying the dynamics of compliant DNA nanostructures, where conformational fluctuations become important, multiple deformation mechanisms exist, and continuum approaches may not yield accurate properties.

Circularized Chromosome with a Large Palindromic Structure in Streptomyces griseus Mutants

PubMed Central

Uchida, Tetsuya; Ishihara, Naoto; Zenitani, Hiroyuki; Hiratsu, Keiichiro; Kinashi, Haruyasu

2004-01-01

Streptomyces linear chromosomes display various types of rearrangements after telomere deletion, including circularization, arm replacement, and amplification. We analyzed the new chromosomal deletion mutants Streptomyces griseus 301-22-L and 301-22-M. In these mutants, chromosomal arm replacement resulted in long terminal inverted repeats (TIRs) at both ends; different sizes were deleted again and recombined inside the TIRs, resulting in a circular chromosome with an extremely large palindrome. Short palindromic sequences were found in parent strain 2247, and these sequences might have played a role in the formation of this unique structure. Dynamic structural changes of Streptomyces linear chromosomes shown by this and previous studies revealed extraordinary strategies of members of this genus to keep a functional chromosome, even if it is linear or circular. PMID:15150216

How does a planet excite multiple spiral arms?

NASA Astrophysics Data System (ADS)

Bae, Jaehan; Zhu, Zhaohuan

2018-01-01

Protoplanetary disk simulations show that a single planet excites multiple spiral arms in the background disk, potentially supported by the multi-armed spirals revealed with recent high-resolution observations in some disks. The existence of multiple spiral arms is of importance in many aspects. It is empirically found that the arm-to-arm separation increases as a function of the planetary mass, so one can use the morphology of observed spiral arms to infer the mass of unseen planets. In addition, a spiral arm opens a radial gap as it steepens into a shock, so when a planet excites multiple spiral arms it can open multiple gaps in the disk. Despite the important implications, however, the formation mechanism of multiple spiral arms has not been fully understood by far.In this talk, we explain how a planet excites multiple spiral arms. The gravitational potential of a planet can be decomposed into a Fourier series, a sum of individual azimuthal modes having different azimuthal wavenumbers. Using a linear wave theory, we first demonstrate that appropriate sets of Fourier decomposed waves can be in phase, raising a possibility that constructive interference among the waves can produce coherent structures - spiral arms. More than one spiral arm can form since such constructive interference can occur at different positions in the disk for different sets of waves. We then verify this hypothesis using a suite of two-dimensional hydrodynamic simulations. Finally, we present non-linear behavior in the formation of multiple spiral arms.

Force-Induced Unfolding of Fibronectin in the Extracellular Matrix of Living Cells

PubMed Central

Smith, Michael L; Gourdon, Delphine; Little, William C; Kubow, Kristopher E; Eguiluz, R. Andresen; Luna-Morris, Sheila; Vogel, Viola

2007-01-01

Whether mechanically unfolded fibronectin (Fn) is present within native extracellular matrix fibrils is controversial. Fn extensibility under the influence of cell traction forces has been proposed to originate either from the force-induced lengthening of an initially compact, folded quaternary structure as is found in solution (quaternary structure model, where the dimeric arms of Fn cross each other), or from the force-induced unfolding of type III modules (unfolding model). Clarification of this issue is central to our understanding of the structural arrangement of Fn within fibrils, the mechanism of fibrillogenesis, and whether cryptic sites, which are exposed by partial protein unfolding, can be exposed by cell-derived force. In order to differentiate between these two models, two fluorescence resonance energy transfer schemes to label plasma Fn were applied, with sensitivity to either compact-to-extended conformation (arm separation) without loss of secondary structure or compact-to-unfolded conformation. Fluorescence resonance energy transfer studies revealed that a significant fraction of fibrillar Fn within a three-dimensional human fibroblast matrix is partially unfolded. Complete relaxation of Fn fibrils led to a refolding of Fn. The compactly folded quaternary structure with crossed Fn arms, however, was never detected within extracellular matrix fibrils. We conclude that the resting state of Fn fibrils does not contain Fn molecules with crossed-over arms, and that the several-fold extensibility of Fn fibrils involves the unfolding of type III modules. This could imply that Fn might play a significant role in mechanotransduction processes. PMID:17914904

Mononuclear Ni(II) complexes of Schiff base ligands formed from unsymmetrical tripodal amines of differing arm lengths: Spectral, X-ray crystal structural, antimicrobial and DNA cleavage activity

NASA Astrophysics Data System (ADS)

Keypour, Hassan; Shayesteh, Maryam; Rezaeivala, Majid; Dhers, Sébastien; Küp, Fatma Öztürk; Güllü, Mithat; Ng, Seikweng

2017-11-01

The synthesis of two unsymmetrical N-capped tripodal amines, 2-((4-aminobutyl)(pyridin-2-ylmethyl)amino)ethanol (3) and 3-((2-aminoethyl)(pyridin-2-ylmethyl)amino)propan-1-ol (4) is reported. They feature a longer, 3-hydroxypropyl or butylamino arm than that in the analogues previously employed. All four tripodal amines, 1-4, are equipped with a 2-methylpyridyl-arm, and either an ethylamino-arm (1 and 4), propylamino-arm (2) or butylamino-arm (3). The amines, 3 and 4, have been employed in one pot condensation reactions with salicylaldehyde and its derivatives in the presence of Ni(II) metal ion. A series of new mononuclear complexes, [NiIILaldi](ClO4) or [NiIILaldi(solvent)](ClO4) with different geometry, of Schiff base ligands were generated. X-ray crystal structure determinations of [NiIILOMe3(H2O)](ClO4)·2H2O and [NiIILOMe4](ClO4) revealed them to be mononuclear. The Ni(II) ion in [NiIILOMe4](ClO4) complex is in a distorted square-planar environment whilst this ion is in distorted octahedral environment in [NiIILOMe3(H2O)](ClO4)·2H2O complex despite the longer arm length of L3. While, in related systems in our previous work, they had led to dimeric complexes. These results clearly showed that the variation of the arm lengths of the ligands and metal ions has a remarkable impact on the formation and structure of the complexes. The cleavage of DNA by all synthesised complexes was examined using gel electrophoresis experiments. Also, the antibacterial effects of components were determined against the three Gram-positive bacteria, and against the three Gram-negative bacteria and against the three yeast Candida albicans ATCC 10231, Candida krusei ATCC 1424 and Candida tropicalis ATCC 13803.

Increasing cognitive load attenuates right arm swing in healthy human walking

NASA Astrophysics Data System (ADS)

Killeen, Tim; Easthope, Christopher S.; Filli, Linard; Lőrincz, Lilla; Schrafl-Altermatt, Miriam; Brugger, Peter; Linnebank, Michael; Curt, Armin; Zörner, Björn; Bolliger, Marc

2017-01-01

Human arm swing looks and feels highly automated, yet it is increasingly apparent that higher centres, including the cortex, are involved in many aspects of locomotor control. The addition of a cognitive task increases arm swing asymmetry during walking, but the characteristics and mechanism of this asymmetry are unclear. We hypothesized that this effect is lateralized and a Stroop word-colour naming task-primarily involving left hemisphere structures-would reduce right arm swing only. We recorded gait in 83 healthy subjects aged 18-80 walking normally on a treadmill and while performing a congruent and incongruent Stroop task. The primary measure of arm swing asymmetry-an index based on both three-dimensional wrist trajectories in which positive values indicate proportionally smaller movements on the right-increased significantly under dual-task conditions in those aged 40-59 and further still in the over-60s, driven by reduced right arm flexion. Right arm swing attenuation appears to be the norm in humans performing a locomotor-cognitive dual-task, confirming a prominent role of the brain in locomotor behaviour. Women under 60 are surprisingly resistant to this effect, revealing unexpected gender differences atop the hierarchical chain of locomotor control.

MOLECULAR GAS EVOLUTION ACROSS A SPIRAL ARM IN M51

DOE Office of Scientific and Technical Information (OSTI.GOV)

Egusa, Fumi; Scoville, Nick; Koda, Jin, E-mail: fegusa@ir.isas.jaxa.jp

We present sensitive and high angular resolution CO(1-0) data obtained by the Combined Array for Research in Millimeter-wave Astronomy observations toward the nearby grand-design spiral galaxy M51. The angular resolution of 0.''7 corresponds to 30 pc, which is similar to the typical size of giant molecular clouds (GMCs), and the sensitivity is also high enough to detect typical GMCs. Within the 1' field of view centered on a spiral arm, a number of GMC-scale structures are detected as clumps. However, only a few clumps are found to be associated with each giant molecular association (GMA) and more than 90% ofmore » the total flux is resolved out in our data. Considering the high sensitivity and resolution of our data, these results indicate that GMAs are not mere confusion with GMCs but plausibly smooth structures. In addition, we have found that the most massive clumps are located downstream of the spiral arm, which suggests that they are at a later stage of molecular cloud evolution across the arm and plausibly are cores of GMAs. By comparing with H{alpha} and Pa{alpha} images, most of these cores are found to have nearby star-forming regions. We thus propose an evolutionary scenario for the interstellar medium, in which smaller molecular clouds collide to form smooth GMAs at spiral arm regions and then star formation is triggered in the GMA cores. Our new CO data have revealed the internal structure of GMAs at GMC scales, finding the most massive substructures on the downstream side of the arm in close association with the brightest H II regions.« less

Deployable reflector structure

NASA Technical Reports Server (NTRS)

Mikulas, Martin, Jr. (Inventor); Hoberman, Charles (Inventor)

1993-01-01

A deployable reflector structure is presented. The structure has a number of movable reflector panels pivotably supported on rigid arms. Several such arms are pivotably connected to a central structure. The arm can move in starburst fashion from a packaged stage, where all arms are vertical, to a deployed stage, where all arms are horizontal. All of the movable reflector panels are maintained at a predetermined angle to an axis of the reflector structure when the arms are pivoted. The reflector panels are stacked tightly on top of each other in the packaged state of the reflector structure. Simple mechanisms are used for avoiding interference between panels on different arms in the packaged stage and for fitting the movable panels together like tiles in the deployed stage.

Models of Tidally Induced Gas Filaments in the Magellanic Stream

NASA Astrophysics Data System (ADS)

Pardy, Stephen A.; D’Onghia, Elena; Fox, Andrew J.

2018-04-01

The Magellanic Stream and Leading Arm of H I that stretches from the Large and Small Magellanic Clouds (LMC and SMC) and over 200° of the Southern sky is thought to be formed from multiple encounters between the LMC and SMC. In this scenario, most of the gas in the Stream and Leading Arm is stripped from the SMC, yet recent observations have shown a bifurcation of the Trailing Arm that reveals LMC origins for some of the gas. Absorption measurements in the Stream also reveal an order of magnitude more gas than in current tidal models. We present hydrodynamical simulations of the multiple encounters between the LMC and SMC at their first pass around the Milky Way, assuming that the Clouds were more extended and gas-rich in the past. Our models create filamentary structures of gas in the Trailing Stream from both the LMC and SMC. While the SMC trailing filament matches the observed Stream location, the LMC filament is offset. In addition, the total observed mass of the Stream in these models is underestimated by a factor of four when the ionized component is accounted for. Our results suggest that there should also be gas stripped from both the LMC and SMC in the Leading Arm, mirroring the bifurcation in the Trailing Stream. This prediction is consistent with recent measurements of spatial variation in chemical abundances in the Leading Arm, which show that gas from multiple sources is present, although its nature is still uncertain.

Electro-dynamic machine, system and method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ouyang, Wen; Ramanan, Varagur

One embodiment is a unique Vernier machine comprising a rotor and a stator. The rotor comprises a back portion and a plurality of permanent magnets. The stator comprises a plurality of ferromagnetic arm structures, a plurality of ferromagnetic pole structures extending from each of the ferromagnetic arm structures in a direction toward the permanent magnets, and a plurality of conductive windings disposed about respective ones of the plurality of ferromagnetic arm structures. The ferromagnetic pole structures are structured to collect magnetic flux from the permanent magnets. The ferromagnetic pole structures of each of said ferromagnetic arm structures are spaced apartmore » from one another according to a non-uniform pattern such that the ferromagnetic pole structures of a given ferromagnetic arm structure have substantially the same angular position relative to the permanent magnets radially opposite from the ferromagnetic pole structures of the given ferromagnetic arm structure.« less

Light production by the arm tips of the deep-sea cephalopod Vampyroteuthis infernalis.

PubMed

Robison, Bruce H; Reisenbichler, Kim R; Hunt, James C; Haddock, Steven H D

2003-10-01

The archaic, deep-sea cephalopod Vampyroteuthis infernalis occurs in dark, oxygen-poor waters below 600 m off Monterey Bay, California. Living specimens, collected gently with a remotely operated vehicle (ROV) and quickly transported to a laboratory ashore, have revealed two hitherto undescribed means of bioluminescent expression for the species. In the first, light is produced by a new type of organ located at the tips of all eight arms. In the second, a viscous fluid containing microscopic luminous particles is released from the arm tips to form a glowing cloud around the animal. Both modes of light production are apparently linked to anti-predation strategies. Use of the tip-lights is readily educed by contact stimuli, while fluid expulsion has a much higher triggering threshold. Coelenterazine and luciferase are the chemical precursors of light production. This paper presents observations on the structure and operation of the arm-tip light organs, the character of the luminous cloud, and how the light they produce is incorporated into behavioral patterns.

Spiral density waves in a young protoplanetary disk.

PubMed

Pérez, Laura M; Carpenter, John M; Andrews, Sean M; Ricci, Luca; Isella, Andrea; Linz, Hendrik; Sargent, Anneila I; Wilner, David J; Henning, Thomas; Deller, Adam T; Chandler, Claire J; Dullemond, Cornelis P; Lazio, Joseph; Menten, Karl M; Corder, Stuartt A; Storm, Shaye; Testi, Leonardo; Tazzari, Marco; Kwon, Woojin; Calvet, Nuria; Greaves, Jane S; Harris, Robert J; Mundy, Lee G

2016-09-30

Gravitational forces are expected to excite spiral density waves in protoplanetary disks, disks of gas and dust orbiting young stars. However, previous observations that showed spiral structure were not able to probe disk midplanes, where most of the mass is concentrated and where planet formation takes place. Using the Atacama Large Millimeter/submillimeter Array, we detected a pair of trailing symmetric spiral arms in the protoplanetary disk surrounding the young star Elias 2-27. The arms extend to the disk outer regions and can be traced down to the midplane. These millimeter-wave observations also reveal an emission gap closer to the star than the spiral arms. We argue that the observed spirals trace shocks of spiral density waves in the midplane of this young disk. Copyright © 2016, American Association for the Advancement of Science.

3D model for Cancerous Inhibitor of Protein Phosphatase 2A armadillo domain unveils highly conserved protein-protein interaction characteristics.

PubMed

Dahlström, Käthe M; Salminen, Tiina A

2015-12-07

Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A) is a human oncoprotein, which exerts its cancer-promoting function through interaction with other proteins, for example Protein Phosphatase 2A (PP2A) and MYC. The lack of structural information for CIP2A significantly prevents the design of anti-cancer therapeutics targeting this protein. In an attempt to counteract this fact, we modeled the three-dimensional structure of the N-terminal domain (CIP2A-ArmRP), analyzed key areas and amino acids, and coupled the results to the existing literature. The model reliably shows a stable armadillo repeat fold with a positively charged groove. The fact that this conserved groove highly likely binds peptides is corroborated by the presence of a conserved polar ladder, which is essential for the proper peptide-binding mode of armadillo repeat proteins and, according to our results, several known CIP2A interaction partners appropriately possess an ArmRP-binding consensus motif. Moreover, we show that Arg229Gln, which has been linked to the development of cancer, causes a significant change in charge and surface properties of CIP2A-ArmRP. In conclusion, our results reveal that CIP2A-ArmRP shares the typical fold, protein-protein interaction site and interaction patterns with other natural armadillo proteins and that, presumably, several interaction partners bind into the central groove of the modeled CIP2A-ArmRP. By providing essential structural characteristics of CIP2A, the present study significantly increases our knowledge on how CIP2A interacts with other proteins in cancer progression and how to develop new therapeutics targeting CIP2A. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Positive Darwinian Selection in the Piston That Powers Proton Pumps in Complex I of the Mitochondria of Pacific Salmon

PubMed Central

Garvin, Michael R.; Bielawski, Joseph P.; Gharrett, Anthony J.

2011-01-01

The mechanism of oxidative phosphorylation is well understood, but evolution of the proteins involved is not. We combined phylogenetic, genomic, and structural biology analyses to examine the evolution of twelve mitochondrial encoded proteins of closely related, yet phenotypically diverse, Pacific salmon. Two separate analyses identified the same seven positively selected sites in ND5. A strong signal was also detected at three sites of ND2. An energetic coupling analysis revealed several structures in the ND5 protein that may have co-evolved with the selected sites. These data implicate Complex I, specifically the piston arm of ND5 where it connects the proton pumps, as important in the evolution of Pacific salmon. Lastly, the lineage to Chinook experienced rapid evolution at the piston arm. PMID:21969854

Positive Darwinian selection in the piston that powers proton pumps in complex I of the mitochondria of Pacific salmon.

PubMed

Garvin, Michael R; Bielawski, Joseph P; Gharrett, Anthony J

2011-01-01

The mechanism of oxidative phosphorylation is well understood, but evolution of the proteins involved is not. We combined phylogenetic, genomic, and structural biology analyses to examine the evolution of twelve mitochondrial encoded proteins of closely related, yet phenotypically diverse, Pacific salmon. Two separate analyses identified the same seven positively selected sites in ND5. A strong signal was also detected at three sites of ND2. An energetic coupling analysis revealed several structures in the ND5 protein that may have co-evolved with the selected sites. These data implicate Complex I, specifically the piston arm of ND5 where it connects the proton pumps, as important in the evolution of Pacific salmon. Lastly, the lineage to Chinook experienced rapid evolution at the piston arm.

Gravity study of the Central African Rift system: A model of continental disruption 1. The Ngaoundere and Abu Gabra Rifts

NASA Astrophysics Data System (ADS)

Browne, S. E.; Fairhead, J. D.

1983-05-01

A regional compilation of published and unpublished gravity data for Central Africa is presented and reveals the presence of a major rift system, called here, the Central African Rift System. It is proposed that the junction area between the Ngaoundere and Abu Gabra rift arms in Western Sudan forms an incipient intraplate, triple-junction with the as yet unfractured, but domally uplifted and volcanically active, Darfur swell. It is only the Darfur swell that shows any similarities to the uplift and rift history of East Africa. The other two rifts arms are considered to be structurally similar to the early stages of passive margin development and thus reflect more closely the initial processes of continental fragmentation than the structures associated with rifting in East Africa.

Mapping the pericentric heterochromatin by comparative genomic hybridization analysis and chromosome deletions in Drosophila melanogaster

PubMed Central

He, Bing; Caudy, Amy; Parsons, Lance; Rosebrock, Adam; Pane, Attilio; Raj, Sandeep; Wieschaus, Eric

2012-01-01

Heterochromatin represents a significant portion of eukaryotic genomes and has essential structural and regulatory functions. Its molecular organization is largely unknown due to difficulties in sequencing through and assembling repetitive sequences enriched in the heterochromatin. Here we developed a novel strategy using chromosomal rearrangements and embryonic phenotypes to position unmapped Drosophila melanogaster heterochromatic sequence to specific chromosomal regions. By excluding sequences that can be mapped to the assembled euchromatic arms, we identified sequences that are specific to heterochromatin and used them to design heterochromatin specific probes (“H-probes”) for microarray. By comparative genomic hybridization (CGH) analyses of embryos deficient for each chromosome or chromosome arm, we were able to map most of our H-probes to specific chromosome arms. We also positioned sequences mapped to the second and X chromosomes to finer intervals by analyzing smaller deletions with breakpoints in heterochromatin. Using this approach, we were able to map >40% (13.9 Mb) of the previously unmapped heterochromatin sequences assembled by the whole-genome sequencing effort on arm U and arm Uextra to specific locations. We also identified and mapped 110 kb of novel heterochromatic sequences. Subsequent analyses revealed that sequences located within different heterochromatic regions have distinct properties, such as sequence composition, degree of repetitiveness, and level of underreplication in polytenized tissues. Surprisingly, although heterochromatin is generally considered to be transcriptionally silent, we detected region-specific temporal patterns of transcription in heterochromatin during oogenesis and early embryonic development. Our study provides a useful approach to elucidate the molecular organization and function of heterochromatin and reveals region-specific variation of heterochromatin. PMID:22745230

Recombination of an intrachromosomal paracentric insertion of chromosome 3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Best, R.G.; Burnett, W.J.; Brock, J.K.

1994-09-01

Cytogenetic studies were initiated on a newborn female due to multiple congenital anomalies including microcephaly, clinodactyly, abnormal positioning of hands, left facial palsy, heart defect, sacral dimple, and facial dysmorphic features. Facial features were described as low set rotated ears, nystagmus, and a small, flattened nose. A structural rearrangement of the long arm of chromosome 3 was observed with a complex banding pattern. Study of parental chromosomes revealed a normal male pattern for the father, and an intrachromosomal insertion on the long arm of chromosome 3 for the mother described as 46,XX,dir ins(3)(q21q23q26.2). Further characterization of the proband`s structurally abnormalmore » chromosome 3 revealed a karyotype best described as: 46,XX,rec(3),dupq23{r_arrow}q26.2::q21{r_arrow}q23,dir ins(3)(q21q23q26.2), which is a partial duplication of both the inserted segment as well as the intervening segment between the inserted segment and the insertion site. This would appear to be the result of a three-strand double cross-over within the insertion loop. Molecular cytogenetic studies are presently underway to further elucidate chromosome structure of the proband and her mother.« less

Structural Studies of Three-Arm Star Block Copolymers Exposed to Extreme Stretch Suggests a Persistent Polymer Tube

NASA Astrophysics Data System (ADS)

Mortensen, Kell; Borger, Anine L.; Kirkensgaard, Jacob J. K.; Garvey, Christopher J.; Almdal, Kristoffer; Dorokhin, Andriy; Huang, Qian; Hassager, Ole

2018-05-01

We present structural small-angle neutron scattering studies of a three-armed polystyrene star polymer with short deuterated segments at the end of each arm. We show that the form factor of the three-armed star molecules in the relaxed state agrees with that of the random phase approximation of Gaussian chains. Upon exposure to large extensional flow conditions, the star polymers change conformation resulting in a highly stretched structure that mimics a fully extended three-armed tube model. All three arms are parallel to the flow, one arm being either in positive or negative stretching direction, while the two other arms are oriented parallel, right next to each other in the direction opposite to the first arm.

Microscopic insight into the bilateral formation of carbon spirals from a symmetric iron core

PubMed Central

Shiozawa, Hidetsugu; Bachmatiuk, Alicja; Stangl, Andreas; Cox, David C.; Silva, S. Ravi P.; Rümmeli, Mark H.; Pichler, Thomas

2013-01-01

Mirrored carbon-spirals have been produced from pressured ferrocene via the bilateral extrusion of the spiral pairs from an iron core. A parametric plot of the surface geometry displays the fractal growth of the conical helix made with the logarithmic spiral. Electron microscopy studies show the core is a crystalline cementite which grows and transforms its shape from spherical to biconical as it extrudes two spiralling carbon arms. In a cross section along the arms we observe graphitic flakes arranged in a herringbone structure, normal to which defects propagate. Local-wave-pattern analysis reveals nanoscale defect patterns of two-fold symmetry around the core. The data suggest that the bilateral growth originates from a globular cementite crystal with molten surfaces and the nano-defects shape emerging hexagonal carbon into a fractal structure. Understanding and knowledge obtained provide a basis for the controlled production of advanced carbon materials with designed geometries. PMID:23670649

An intermediate along the recovery stroke of myosin VI revealed by X-ray crystallography and molecular dynamics.

PubMed

Blanc, Florian; Isabet, Tatiana; Benisty, Hannah; Sweeney, H Lee; Cecchini, Marco; Houdusse, Anne

2018-06-12

Myosins form a class of actin-based, ATPase motor proteins that mediate important cellular functions such as cargo transport and cell motility. Their functional cycle involves two large-scale swings of the lever arm: the force-generating powerstroke, which takes place on actin, and the recovery stroke during which the lever arm is reprimed into an armed configuration. Previous analyses of the prerecovery (postrigor) and postrecovery (prepowerstroke) states predicted that closure of switch II in the ATP binding site precedes the movement of the converter and the lever arm. Here, we report on a crystal structure of myosin VI, called pretransition state (PTS), which was solved at 2.2 Å resolution. Structural analysis and all-atom molecular dynamics simulations are consistent with PTS being an intermediate along the recovery stroke, where the Relay/SH1 elements adopt a postrecovery conformation, and switch II remains open. In this state, the converter appears to be largely uncoupled from the motor domain and explores an ensemble of partially reprimed configurations through extensive, reversible fluctuations. Moreover, we found that the free energy cost of hydrogen-bonding switch II to ATP is lowered by more than 10 kcal/mol compared with the prerecovery state. These results support the conclusion that closing of switch II does not initiate the recovery stroke transition in myosin VI. Rather, they suggest a mechanism in which lever arm repriming would be mostly driven by thermal fluctuations and eventually stabilized by the switch II interaction with the nucleotide in a ratchet-like fashion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du, Xinyu; Xu, Ye; Yang, Ji

The lack of arm tracers, especially remote tracers, is one of the most difficult problems preventing us from studying the structure of the Milky Way. Fortunately, with its high-sensitivity CO survey, the Milky Way Imaging Scroll Painting (MWISP) project offers such an opportunity. Since completing about one-third of its mission, an area of l = [100, 150]°, b = [−3, 5]° has nearly been covered. The Outer arm of the Milky Way first clearly revealed its shape in the second galactic quadrant in the form of molecular gas—this is the first time that the Outer arm has been reported inmore » such a large-scale mapping of molecular gas. Using the 115 GHz {sup 12}CO(1–0) data of MWISP at the LSR velocity ≃[−100, −60] km s{sup −1} and in the area mentioned above, we have detected 481 molecular clouds in total, and among them 332 (about 69%) are newly detected and 457 probably belong to the Outer arm. The total mass of the detected Outer arm clouds is ∼3.1 × 10{sup 6} M {sub ⊙}. Assuming that the spiral arm is a logarithmic spiral, the pitch angle is fitted as ∼13.°1. Besides combining both the CO data from MWISP and the 21 cm H i data from the Canadian Galactic Plane Survey (CGPS), the gas distribution, warp, and thickness of the Outer arm are also studied.« less

Patterns of arm muscle activation involved in octopus reaching movements.

PubMed

Gutfreund, Y; Flash, T; Fiorito, G; Hochner, B

1998-08-01

The extreme flexibility of the octopus arm allows it to perform many different movements, yet octopuses reach toward a target in a stereotyped manner using a basic invariant motor structure: a bend traveling from the base of the arm toward the tip (Gutfreund et al., 1996a). To study the neuronal control of these movements, arm muscle activation [electromyogram (EMG)] was measured together with the kinematics of reaching movements. The traveling bend is associated with a propagating wave of muscle activation, with maximal muscle activation slightly preceding the traveling bend. Tonic activation was occasionally maintained afterward. Correlation of the EMG signals with the kinematic variables (velocities and accelerations) reveals that a significant part of the kinematic variability can be explained by the level of muscle activation. Furthermore, the EMG level measured during the initial stages of movement predicts the peak velocity attained toward the end of the reaching movement. These results suggest that feed-forward motor commands play an important role in the control of movement velocity and that simple adjustment of the excitation levels at the initial stages of the movement can set the velocity profile of the whole movement. A simple model of octopus arm extension is proposed in which the driving force is set initially and is then decreased in proportion to arm diameter at the bend. The model qualitatively reproduces the typical velocity profiles of octopus reaching movements, suggesting a simple control mechanism for bend propagation in the octopus arm.

Design of a biomimetic robotic octopus arm.

PubMed

Laschi, C; Mazzolai, B; Mattoli, V; Cianchetti, M; Dario, P

2009-03-01

This paper reports the rationale and design of a robotic arm, as inspired by an octopus arm. The octopus arm shows peculiar features, such as the ability to bend in all directions, to produce fast elongations, and to vary its stiffness. The octopus achieves these unique motor skills, thanks to its peculiar muscular structure, named muscular hydrostat. Different muscles arranged on orthogonal planes generate an antagonistic action on each other in the muscular hydrostat, which does not change its volume during muscle contractions, and allow bending and elongation of the arm and stiffness variation. By drawing inspiration from natural skills of octopus, and by analysing the geometry and mechanics of the muscular structure of its arm, we propose the design of a robot arm consisting of an artificial muscular hydrostat structure, which is completely soft and compliant, but also able to stiffen. In this paper, we discuss the design criteria of the robotic arm and how this design and the special arrangement of its muscular structure may bring the building of a robotic arm into being, by showing the results obtained by mathematical models and prototypical mock-ups.

HOW SPIRALS AND GAPS DRIVEN BY COMPANIONS IN PROTOPLANETARY DISKS APPEAR IN SCATTERED LIGHT AT ARBITRARY VIEWING ANGLES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, Ruobing; Fung, Jeffrey; Chiang, Eugene, E-mail: rdong2013@berkeley.edu

2016-07-20

Direct imaging observations of protoplanetary disks at near-infrared (NIR) wavelengths have revealed structures of potentially planetary origin. Investigations of observational signatures from planet-induced features have so far focused on disks viewed face-on. Combining 3D hydrodynamics and radiative transfer simulations, we study how the appearance of the spiral arms and the gap produced in a disk by a companion varies with inclination and position angle in NIR scattered light. We compare the cases of a 3 M {sub J} and a 0.1 M {sub ⊙} companion, and make predictions suitable for testing with Gemini/GPI, Very Large Telescope/NACO/SPHERE, and Subaru/HiCIAO/SCExAO. We findmore » that the two trailing arms produced by an external perturber can have a variety of morphologies in inclined systems—they may appear as one trailing arm; two trailing arms on the same side of the disk; or two arms winding in opposite directions. The disk ring outside a planetary gap may also mimic spiral arms when viewed at high inclinations. We suggest potential explanations for the features observed in HH 30, HD 141569 A, AK Sco, HD 100546, and AB Aur. We emphasize that inclined views of companion-induced features cannot be converted into face-on views using simple and commonly practiced image deprojections.« less

Small-angle X-ray solution scattering study of the multi-aminoacyl-tRNA synthetase complex reveals an elongated and multi-armed particle.

PubMed

Dias, José; Renault, Louis; Pérez, Javier; Mirande, Marc

2013-08-16

In animal cells, nine aminoacyl-tRNA synthetases are associated with the three auxiliary proteins p18, p38, and p43 to form a stable and conserved large multi-aminoacyl-tRNA synthetase complex (MARS), whose molecular mass has been proposed to be between 1.0 and 1.5 MDa. The complex acts as a molecular hub for coordinating protein synthesis and diverse regulatory signal pathways. Electron microscopy studies defined its low resolution molecular envelope as an overall rather compact, asymmetric triangular shape. Here, we have analyzed the composition and homogeneity of the native mammalian MARS isolated from rabbit liver and characterized its overall internal structure, size, and shape at low resolution by hydrodynamic methods and small-angle x-ray scattering in solution. Our data reveal that the MARS exhibits a much more elongated and multi-armed shape than expected from previous reports. The hydrodynamic and structural features of the MARS are large compared with other supramolecular assemblies involved in translation, including ribosome. The large dimensions and non-compact structural organization of MARS favor a large protein surface accessibility for all its components. This may be essential to allow structural rearrangements between the catalytic and cis-acting tRNA binding domains of the synthetases required for binding the bulky tRNA substrates. This non-compact architecture may also contribute to the spatiotemporal controlled release of some of its components, which participate in non-canonical functions after dissociation from the complex.

KINEMATIC ANALYSIS OF NUCLEAR SPIRALS: FEEDING THE BLACK HOLE IN NGC 1097

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van de Ven, Glenn; Fathi, Kambiz, E-mail: glenn@mpia.d, E-mail: kambiz@astro.su.s

2010-11-01

We present a harmonic expansion of the observed line-of-sight velocity field as a method to recover and investigate spiral structures in the nuclear regions of galaxies. We apply it to the emission-line velocity field within the circumnuclear star-forming ring of NGC 1097, obtained with the GMOS-IFU spectrograph. The radial variation of the third harmonic terms is well described by a logarithmic spiral, from which we interpret that the gravitational potential is weakly perturbed by a two-arm spiral density wave with an inferred pitch angle of 52{sup 0} {+-} 4{sup 0}. This interpretation predicts a two-arm spiral distortion in the surfacemore » brightness, as hinted by the dust structures in central images of NGC 1097, and predicts a combined one-arm and three-arm spiral structure in the velocity field, as revealed in the non-circular motions of the ionized gas. Next, we use a simple spiral perturbation model to constrain the fraction of the measured non-circular motions that is due to radial inflow. We combine the resulting inflow velocity with the gas density in the spiral arms, inferred from emission-line ratios, to estimate the mass inflow rate as a function of radius, which reaches about 0.011 M{sub sun} yr{sup -1} at a distance of 70 pc from the center. This value corresponds to a fraction of about 4.2 x 10{sup -3} of the Eddington mass accretion rate onto the central black hole in this LINER/Seyfert1 galaxy. We conclude that the line-of-sight velocity can not only provide a cleaner view of nuclear spirals than the associated dust, but that the presented method also allows the quantitative study of these possibly important links in fueling the centers of galaxies, including providing a constraint on the mass inflow rate as a function of radius.« less

Enabling Rapid Integration of Combined Arms Teams into a Brigade Combat Team Organizational Structure

DTIC Science & Technology

2017-06-01

organizational structure , fixed vs. mobile forward operating base (FOB) synchronization, prior preparation, and unit capabilities. 5. Ideas to Improve...Technical Report 1356 Enabling Rapid Integration of Combined Arms Teams into a Brigade Combat Team Organizational Structure ...2012 - May 2014 4. TITLE AND SUBTITLE Enabling Rapid Integration of Combined Arms Teams into a Brigade Combat Team Organizational Structure

Dust-trapping Vortices and a Potentially Planet-triggered Spiral Wake in the Pre-transitional Disk of V1247 Orionis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kraus, Stefan; Kreplin, Alexander; Young, Alison K.

The radial drift problem constitutes one of the most fundamental problems in planet formation theory, as it predicts particles to drift into the star before they are able to grow to planetesimal size. Dust-trapping vortices have been proposed as a possible solution to this problem, as they might be able to trap particles over millions of years, allowing them to grow beyond the radial drift barrier. Here, we present ALMA 0.″04 resolution imaging of the pre-transitional disk of V1247 Orionis that reveals an asymmetric ring as well as a sharply confined crescent structure, resembling morphologies seen in theoretical models ofmore » vortex formation. The asymmetric ring (at 0.″17 = 54 au separation from the star) and the crescent (at 0.″38 = 120 au) seem smoothly connected through a one-armed spiral-arm structure that has been found previously in scattered light. We propose a physical scenario with a planet orbiting at ∼0.″3 ≈ 100 au, where the one-armed spiral arm detected in polarized light traces the accretion stream feeding the protoplanet. The dynamical influence of the planet clears the gap between the ring and the crescent and triggers two vortices that trap millimeter-sized particles, namely, the crescent and the bright asymmetry seen in the ring. We conducted dedicated hydrodynamics simulations of a disk with an embedded planet, which results in similar spiral-arm morphologies as seen in our scattered-light images. At the position of the spiral wake and the crescent we also observe {sup 12}CO(3-2) and H{sup 12}CO{sup +} (4-3) excess line emission, likely tracing the increased scale-height in these disk regions.« less

Dust-trapping Vortices and a Potentially Planet-triggered Spiral Wake in the Pre-transitional Disk of V1247 Orionis

NASA Astrophysics Data System (ADS)

Kraus, Stefan; Kreplin, Alexander; Fukugawa, Misato; Muto, Takayuki; Sitko, Michael L.; Young, Alison K.; Bate, Matthew R.; Grady, Carol; Harries, Tim T.; Monnier, John D.; Willson, Matthew; Wisniewski, John

2017-10-01

The radial drift problem constitutes one of the most fundamental problems in planet formation theory, as it predicts particles to drift into the star before they are able to grow to planetesimal size. Dust-trapping vortices have been proposed as a possible solution to this problem, as they might be able to trap particles over millions of years, allowing them to grow beyond the radial drift barrier. Here, we present ALMA 0.″04 resolution imaging of the pre-transitional disk of V1247 Orionis that reveals an asymmetric ring as well as a sharply confined crescent structure, resembling morphologies seen in theoretical models of vortex formation. The asymmetric ring (at 0.″17 = 54 au separation from the star) and the crescent (at 0.″38 = 120 au) seem smoothly connected through a one-armed spiral-arm structure that has been found previously in scattered light. We propose a physical scenario with a planet orbiting at ˜0.″3 ≈ 100 au, where the one-armed spiral arm detected in polarized light traces the accretion stream feeding the protoplanet. The dynamical influence of the planet clears the gap between the ring and the crescent and triggers two vortices that trap millimeter-sized particles, namely, the crescent and the bright asymmetry seen in the ring. We conducted dedicated hydrodynamics simulations of a disk with an embedded planet, which results in similar spiral-arm morphologies as seen in our scattered-light images. At the position of the spiral wake and the crescent we also observe 12CO(3-2) and H12CO+ (4-3) excess line emission, likely tracing the increased scale-height in these disk regions.

An Investigation of the Ionization Structure of the Carina Spiral Arm with WHAM

NASA Astrophysics Data System (ADS)

Benjamin, Robert A.; Krishnarao, Dhanesh; Haffner, L. Matthew

2018-01-01

Recent investigations of the Sagittarius-Carina spiral arm with the Wisconsin H-alpha Mapper (Krishnarao et al 2017) show the presence of ionized gas stretching up to three kiloparsecs above and below the Carina section of this spiral arm. This arm segment, which wraps outside the solar circle in the fourth quadrant of the Galactic disk, seems to be unusual when compared to the other Milky Way spiral arms measured with WHAM. We review the status of what is known about the vertical ionization structure of the spiral arms of the Milky Way Galaxy and relate the properties of this spiral arm section to recent investigations of midplane HII regions and star formation in the Milky Way disk. We discuss potential implications of this star formation and ionization for our understanding of Milky Way Galactic structure.

Simultaneous structure-activity studies and arming of natural products by C-H amination reveal cellular targets of eupalmerin acetate.

PubMed

Li, Jing; Cisar, Justin S; Zhou, Cong-Ying; Vera, Brunilda; Williams, Howard; Rodríguez, Abimael D; Cravatt, Benjamin F; Romo, Daniel

2013-06-01

Natural products have a venerable history of, and enduring potential for the discovery of useful biological activity. To fully exploit this, the development of chemical methodology that can functionalize unique sites within these complex structures is highly desirable. Here, we describe the use of rhodium(II)-catalysed C-H amination reactions developed by Du Bois to carry out simultaneous structure-activity relationship studies and arming (alkynylation) of natural products at 'unfunctionalized' positions. Allylic and benzylic C-H bonds in the natural products undergo amination while olefins undergo aziridination, and tertiary amine-containing natural products are converted to amidines by a C-H amination-oxidation sequence or to hydrazine sulfamate zwitterions by an unusual N-amination. The alkynylated derivatives are ready for conversion into cellular probes that can be used for mechanism-of-action studies. Chemo- and site-selectivity was studied with a diverse library of natural products. For one of these-the marine-derived anticancer diterpene, eupalmerin acetate-quantitative proteome profiling led to the identification of several protein targets in HL-60 cells, suggesting a polypharmacological mode of action.

Simultaneous structure-activity studies and arming of natural products by C-H amination reveal cellular targets of eupalmerin acetate

NASA Astrophysics Data System (ADS)

Li, Jing; Cisar, Justin S.; Zhou, Cong-Ying; Vera, Brunilda; Williams, Howard; Rodríguez, Abimael D.; Cravatt, Benjamin F.; Romo, Daniel

2013-06-01

Natural products have a venerable history of, and enduring potential for the discovery of useful biological activity. To fully exploit this, the development of chemical methodology that can functionalize unique sites within these complex structures is highly desirable. Here, we describe the use of rhodium(II)-catalysed C-H amination reactions developed by Du Bois to carry out simultaneous structure-activity relationship studies and arming (alkynylation) of natural products at ‘unfunctionalized’ positions. Allylic and benzylic C-H bonds in the natural products undergo amination while olefins undergo aziridination, and tertiary amine-containing natural products are converted to amidines by a C-H amination-oxidation sequence or to hydrazine sulfamate zwitterions by an unusual N-amination. The alkynylated derivatives are ready for conversion into cellular probes that can be used for mechanism-of-action studies. Chemo- and site-selectivity was studied with a diverse library of natural products. For one of these—the marine-derived anticancer diterpene, eupalmerin acetate—quantitative proteome profiling led to the identification of several protein targets in HL-60 cells, suggesting a polypharmacological mode of action.

Industrial dual arm robot manipulator for precise assembly of mechanical parts

NASA Astrophysics Data System (ADS)

Park, Chanhun; Kim, Doohyung; Park, Kyoungtaik; Choi, Youngjin

2007-12-01

A new structure of dual arm robot manipulator which consists of two industrial 6-DOF arms and one 2-DOF Torso is introduced. Each industrial 6-DOF arm is able to be used as a stand-alone industrial 6-DOF robot manipulator and as a part of dual arm manipulator at the same time. These structures help the robot maker which is willing to succeed in the emerging dual arm robot market in order to have high competition for the current industrial robot market at same time. Self-collision detection algorithm for multi-arm robot and kinematics algorithms for the developed dual arm robot manipulator which are implemented in our controller are introduced.

Interlocking Mechanism between Molecular Gears Attached to Surfaces.

PubMed

Zhao, Rundong; Zhao, Yan-Ling; Qi, Fei; Hermann, Klaus E; Zhang, Rui-Qin; Van Hove, Michel A

2018-03-27

While molecular machines play an increasingly significant role in nanoscience research and applications, there remains a shortage of investigations and understanding of the molecular gear (cogwheel), which is an indispensable and fundamental component to drive a larger correlated molecular machine system. Employing ab initio calculations, we investigate model systems consisting of molecules adsorbed on metal or graphene surfaces, ranging from very simple triple-arm gears such as PF 3 and NH 3 to larger multiarm gears based on carbon rings. We explore in detail the transmission of slow rotational motion from one gear to the next by these relatively simple molecules, so as to isolate and reveal the mechanisms of the relevant intermolecular interactions. Several characteristics of molecular gears are discussed, in particular the flexibility of the arms and the slipping and skipping between interlocking arms of adjacent gears, which differ from familiar macroscopic rigid gears. The underlying theoretical concepts suggest strongly that other analogous structures may also exhibit similar behavior which may inspire future exploration in designing large correlated molecular machines.

KSC-2009-5915

NASA Image and Video Library

2009-10-27

CAPE CANAVERAL, Fla. – Sunrise at Launch Pad 39B at NASA's Kennedy Space Center in Florida reveals the rotating service structure and the arms of the vehicle stabilization system have been retracted from around the Constellation Program's 327-foot-tall Ares I-X rocket for launch. The transfer of the pad from the Space Shuttle Program to the Constellation Program took place May 31. Modifications made to the pad include the removal of shuttle unique subsystems, such as the orbiter access arm and a section of the gaseous oxygen vent arm, and the installation of three 600-foot lightning towers, access platforms, environmental control systems and a vehicle stabilization system. The data returned from more than 700 sensors throughout the rocket will be used to refine the design of future launch vehicles and bring NASA one step closer to reaching its exploration goals. The Ares I-X flight test is targeted for Oct. 27. For information on the Ares I-X vehicle and flight test, visit http://www.nasa.gov/aresIX. Photo credit: NASA/Kim Shiflett

High precision detector robot arm system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shu, Deming; Chu, Yong

A method and high precision robot arm system are provided, for example, for X-ray nanodiffraction with an X-ray nanoprobe. The robot arm system includes duo-vertical-stages and a kinematic linkage system. A two-dimensional (2D) vertical plane ultra-precision robot arm supporting an X-ray detector provides positioning and manipulating of the X-ray detector. A vertical support for the 2D vertical plane robot arm includes spaced apart rails respectively engaging a first bearing structure and a second bearing structure carried by the 2D vertical plane robot arm.

Arm position influences the activation patterns of trunk muscles during trunk range-of-motion movements.

PubMed

Siu, Aaron; Schinkel-Ivy, Alison; Drake, Janessa Dm

2016-10-01

To understand the activation patterns of the trunk musculature, it is also important to consider the implications of adjacent structures such as the upper limbs, and the muscles that act to move the arms. This study investigated the effects of arm positions on the activation patterns and co-activation of the trunk musculature and muscles that move the arm during trunk range-of-motion movements (maximum trunk axial twist, flexion, and lateral bend). Fifteen males and fifteen females, asymptomatic for low back pain, performed maximum trunk range-of-motion movements, with three arm positions for axial twist (loose, crossed, abducted) and two positions for flexion and lateral bend (loose, crossed). Electromyographical data were collected for eight muscles bilaterally, and activation signals were cross-correlated between trunk muscles and the muscles that move the arms (upper trapezius, latissimus dorsi). Results revealed consistently greater muscle co-activation (higher cross-correlation coefficients) between the trunk muscles and upper trapezius for the abducted arm position during maximum trunk axial twist, while results for the latissimus dorsi-trunk pairings were more dependent on the specific trunk muscles (either abdominal or back) and latissimus dorsi muscle (either right or left side), as well as the range-of-motion movement. The findings of this study contribute to the understanding of interactions between the upper limbs and trunk, and highlight the influence of arm positions on the trunk musculature. In addition, the comparison of the present results to those of individuals with back or shoulder conditions may ultimately aid in elucidating underlying mechanisms or contributing factors to those conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Automated Quantification of Arbitrary Arm-Segment Structure in Spiral Galaxies

NASA Astrophysics Data System (ADS)

Davis, Darren Robert

This thesis describes a system that, given approximately-centered images of spiral galaxies, produces quantitative descriptions of spiral galaxy structure without the need for per-image human input. This structure information consists of a list of spiral arm segments, each associated with a fitted logarithmic spiral arc and a pixel region. This list-of-arcs representation allows description of arbitrary spiral galaxy structure: the arms do not need to be symmetric, may have forks or bends, and, more generally, may be arranged in any manner with a consistent spiral-pattern center (non-merging galaxies have a sufficiently well-defined center). Such flexibility is important in order to accommodate the myriad structure variations observed in spiral galaxies. From the arcs produced from our method it is possible to calculate measures of spiral galaxy structure such as winding direction, winding tightness, arm counts, asymmetry, or other values of interest (including user-defined measures). In addition to providing information about the spiral arm "skeleton" of each galaxy, our method can enable analyses of brightness within individual spiral arms, since we provide the pixel regions associated with each spiral arm segment. For winding direction, arm tightness, and arm count, comparable information is available (to various extents) from previous efforts; to the extent that such information is available, we find strong correspondence with our output. We also characterize the changes to (and invariances in) our output as a function of modifications to important algorithm parameters. By enabling generation of extensive data about spiral galaxy structure from large-scale sky surveys, our method will enable new discoveries and tests regarding the nature of galaxies and the universe, and will facilitate subsequent work to automatically fit detailed brightness models of spiral galaxies.

Hierarchical star formation across the grand-design spiral NGC 1566

NASA Astrophysics Data System (ADS)

Gouliermis, Dimitrios A.; Elmegreen, Bruce G.; Elmegreen, Debra M.; Calzetti, Daniela; Cignoni, Michele; Gallagher, John S., III; Kennicutt, Robert C.; Klessen, Ralf S.; Sabbi, Elena; Thilker, David; Ubeda, Leonardo; Aloisi, Alessandra; Adamo, Angela; Cook, David O.; Dale, Daniel; Grasha, Kathryn; Grebel, Eva K.; Johnson, Kelsey E.; Sacchi, Elena; Shabani, Fayezeh; Smith, Linda J.; Wofford, Aida

2017-06-01

We investigate how star formation is spatially organized in the grand-design spiral NGC 1566 from deep Hubble Space Telescope photometry with the Legacy ExtraGalactic UV Survey. Our contour-based clustering analysis reveals 890 distinct stellar conglomerations at various levels of significance. These star-forming complexes are organized in a hierarchical fashion with the larger congregations consisting of smaller structures, which themselves fragment into even smaller and more compact stellar groupings. Their size distribution, covering a wide range in length-scales, shows a power law as expected from scale-free processes. We explain this shape with a simple 'fragmentation and enrichment' model. The hierarchical morphology of the complexes is confirmed by their mass-size relation that can be represented by a power law with a fractional exponent, analogous to that determined for fractal molecular clouds. The surface stellar density distribution of the complexes shows a lognormal shape similar to that for supersonic non-gravitating turbulent gas. Between 50 and 65 per cent of the recently formed stars, as well as about 90 per cent of the young star clusters, are found inside the stellar complexes, located along the spiral arms. We find an age difference between young stars inside the complexes and those in their direct vicinity in the arms of at least 10 Myr. This time-scale may relate to the minimum time for stellar evaporation, although we cannot exclude the in situ formation of stars. As expected, star formation preferentially occurs in spiral arms. Our findings reveal turbulent-driven hierarchical star formation along the arms of a grand-design galaxy.

Imaging microscopic structures in pathological retinas using a flood-illumination adaptive optics retinal camera

NASA Astrophysics Data System (ADS)

Viard, Clément; Nakashima, Kiyoko; Lamory, Barbara; Pâques, Michel; Levecq, Xavier; Château, Nicolas

2011-03-01

This research is aimed at characterizing in vivo differences between healthy and pathological retinal tissues at the microscopic scale using a compact adaptive optics (AO) retinal camera. Tests were performed in 120 healthy eyes and 180 eyes suffering from 19 different pathological conditions, including age-related maculopathy (ARM), glaucoma and rare diseases such as inherited retinal dystrophies. Each patient was first examined using SD-OCT and infrared SLO. Retinal areas of 4°x4° were imaged using an AO flood-illumination retinal camera based on a large-stroke deformable mirror. Contrast was finally enhanced by registering and averaging rough images using classical algorithms. Cellular-resolution images could be obtained in most cases. In ARM, AO images revealed granular contents in drusen, which were invisible in SLO or OCT images, and allowed the observation of the cone mosaic between drusen. In glaucoma cases, visual field was correlated to changes in cone visibility. In inherited retinal dystrophies, AO helped to evaluate cone loss across the retina. Other microstructures, slightly larger in size than cones, were also visible in several retinas. AO provided potentially useful diagnostic and prognostic information in various diseases. In addition to cones, other microscopic structures revealed by AO images may also be of interest in monitoring retinal diseases.

A simulation of high energy cosmic ray propagation 2

NASA Technical Reports Server (NTRS)

Honda, M.; Kamata, K.; Kifune, T.; Matsubara, Y.; Mori, M.; Nishijima, K.

1985-01-01

The cosmic ray propagation in the Galactic arm is simulated. The Galactic magnetic fields are known to go along with so called Galactic arms as a main structure with turbulences of the scale about 30pc. The distribution of cosmic ray in Galactic arm is studied. The escape time and the possible anisotropies caused by the arm structure are discussed.

Topological analysis of long-chain branching patterns in polyolefins.

PubMed

Bonchev, D; Markel, E; Dekmezian, A

2001-01-01

Patterns in molecular topology and complexity for long-chain branching are quantitatively described. The Wiener number, the topological complexity index, and a new index of 3-starness are used to quantify polymer structure. General formulas for these indices were derived for the cases of 3-arm star, H-shaped, and B-arm comb polymers. The factors affecting complexity in monodisperse polymer systems are ranked as follows: number of arms > arm length > arm central position approximately equal to arm clustering > total molecular weight approximately equal to backbone molecular weight. Topological indices change rapidly and then plateau as the molecular weight of branches on a polyolefin backbone increases from 0 to 5 kD. Complexity calculations relate 2-arm or 3-arm comb structures to the corresponding 3-arm stars of equivalent complexity but much higher molecular weight. In a subsequent paper, we report the application of topological analysis for developing structure/property relationships for monodisperse polymers. While the focus of the present work is on the description of monodisperse, well-defined architectures, the methods may be extended to the description of polydisperse systems.

Visualizing Key Hinges and a Potential Major Source of Compliance in the Lever Arm of Myosin

DOE Office of Scientific and Technical Information (OSTI.GOV)

J Brown; V Senthil Kumar; E ONeall-Hennessey

2011-12-31

We have determined the 2.3-{angstrom}-resolution crystal structure of a myosin light chain domain, corresponding to one type found in sea scallop catch ('smooth') muscle. This structure reveals hinges that may function in the 'on' and 'off' states of myosin. The molecule adopts two different conformations about the heavy chain 'hook' and regulatory light chain (RLC) helix D. This conformational change results in extended and compressed forms of the lever arm whose lengths differ by 10 {angstrom}. The heavy chain hook and RLC helix D hinges could thus serve as a potential major and localized source of cross-bridge compliance during themore » contractile cycle. In addition, in one of the molecules of the crystal, part of the RLC N-terminal extension is seen in atomic detail and forms a one-turn alpha-helix that interacts with RLC helix D. This extension, whose sequence is highly variable in different myosins, may thus modulate the flexibility of the lever arm. Moreover, the relative proximity of the phosphorylation site to the helix D hinge suggests a potential role for conformational changes about this hinge in the transition between the on and off states of regulated myosins.« less

Visualizing key hinges and a potential major source of compliance in the lever arm of myosin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, J.H.; Robinson, H.; Senthil Kumar, V. S.

2011-01-04

We have determined the 2.3-{angstrom}-resolution crystal structure of a myosin light chain domain, corresponding to one type found in sea scallop catch ('smooth') muscle. This structure reveals hinges that may function in the 'on' and 'off' states of myosin. The molecule adopts two different conformations about the heavy chain 'hook' and regulatory light chain (RLC) helix D. This conformational change results in extended and compressed forms of the lever arm whose lengths differ by 10 {angstrom}. The heavy chain hook and RLC helix D hinges could thus serve as a potential major and localized source of cross-bridge compliance during themore » contractile cycle. In addition, in one of the molecules of the crystal, part of the RLC N-terminal extension is seen in atomic detail and forms a one-turn alpha-helix that interacts with RLC helix D. This extension, whose sequence is highly variable in different myosins, may thus modulate the flexibility of the lever arm. Moreover, the relative proximity of the phosphorylation site to the helix D hinge suggests a potential role for conformational changes about this hinge in the transition between the on and off states of regulated myosins.« less

Small-angle X-ray Solution Scattering Study of the Multi-aminoacyl-tRNA Synthetase Complex Reveals an Elongated and Multi-armed particle*

PubMed Central

Dias, José; Renault, Louis; Pérez, Javier; Mirande, Marc

2013-01-01

In animal cells, nine aminoacyl-tRNA synthetases are associated with the three auxiliary proteins p18, p38, and p43 to form a stable and conserved large multi-aminoacyl-tRNA synthetase complex (MARS), whose molecular mass has been proposed to be between 1.0 and 1.5 MDa. The complex acts as a molecular hub for coordinating protein synthesis and diverse regulatory signal pathways. Electron microscopy studies defined its low resolution molecular envelope as an overall rather compact, asymmetric triangular shape. Here, we have analyzed the composition and homogeneity of the native mammalian MARS isolated from rabbit liver and characterized its overall internal structure, size, and shape at low resolution by hydrodynamic methods and small-angle x-ray scattering in solution. Our data reveal that the MARS exhibits a much more elongated and multi-armed shape than expected from previous reports. The hydrodynamic and structural features of the MARS are large compared with other supramolecular assemblies involved in translation, including ribosome. The large dimensions and non-compact structural organization of MARS favor a large protein surface accessibility for all its components. This may be essential to allow structural rearrangements between the catalytic and cis-acting tRNA binding domains of the synthetases required for binding the bulky tRNA substrates. This non-compact architecture may also contribute to the spatiotemporal controlled release of some of its components, which participate in non-canonical functions after dissociation from the complex. PMID:23836901

Doxorubicin-loaded micelles based on multiarm star-shaped PLGA-PEG block copolymers: influence of arm numbers on drug delivery.

PubMed

Ma, Guilei; Zhang, Chao; Zhang, Linhua; Sun, Hongfan; Song, Cunxian; Wang, Chun; Kong, Deling

2016-01-01

Star-shaped block copolymers based on poly(D,L-lactide-co-glycolide) (PLGA) and poly(ethylene glycol) (PEG) (st-PLGA-PEG) were synthesized with structural variation on arm numbers in order to investigate the relationship between the arm numbers of st-PLGA-PEG copolymers and their micelle properties. st-PLGA-PEG copolymers with arm numbers 3, 4 and 6 were synthesized by using different cores such as trimethylolpropane, pentaerythritol and dipentaerythritol, and were characterized by nuclear magnetic resonance and gel permeation chromatography. The critical micelle concentration decreased with increasing arm numbers in st-PLGA-PEG copolymers. The doxorubicin-loaded st-PLGA-PEG micelles were prepared by a modified nanoprecipitation method. Micellar properties such as particle size, drug loading content and in vitro drug release behavior were investigated as a function of the number of arms and compared with each other. The doxorubicin-loaded 4-arm PLGA-PEG micelles were found to have the highest cellular uptake efficiency and cytotoxicity compared with 3-arm PLGA-PEG micelles and 6-arm PLGA-PEG micelles. The results suggest that structural tailoring of arm numbers from st-PLGA-PEG copolymers could provide a new strategy for designing drug carriers of high efficiency. Structural tailoring of arm numbers from star shaped-PLGA-PEG copolymers (3-arm/4-arm/6-arm-PLGA-PEG) could provide a new strategy for designing drug carriers of high efficiency.

Passive or simulated displacement of one arm (but not its mirror reflection) modulates the involuntary motor behavior of the other arm.

PubMed

Brun, C; Metral, M; Chancel, M; Kavounoudias, A; Luyat, M; Guerraz, M

2015-01-29

Recent studies of both healthy and patient populations have cast doubt on the mirror paradigm's beneficial effect on motor behavior. Indeed, the voluntary arm displacement that accompanies reflection in the mirror may be the determining factor in terms of the motor behavior of the contralateral arm. The objective of the present study was to assess the respective effects of mirror reflection and arm displacement (whether real or simulated) on involuntary motor behavior of the contralateral arm following sustained, isometric contraction (Kohnstamm phenomenon). Our results revealed that (i) passive displacement of one arm (displacement of the left arm via a motorized manipulandum moving at 4°/s) influenced the velocity of the Kohnstamm phenomenon (forearm flexion occurring shortly after the cessation of muscle contraction) in the contralateral arm and (ii) mirror vision had no effect. Indeed, the velocity of the Kohnstamm phenomenon tended to be adjusted to match the velocity of the passive displacement of the other arm. In a second experiment, arm displacement was simulated by vibrating the triceps at 25, 50 or 75 Hz. Results showed that the velocity of the Kohnstamm phenomenon in one arm increased with the vibration frequency applied to the other arm. Our results revealed the occurrence of bimanual coupling because involuntary displacement of one arm was regulated by muscle-related information generated by the actual or simulated displacement of the other arm. In line with the literature data on voluntary motor behavior, our study failed to evidence an additional impact of mirror vision on involuntary motor behavior. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Crystal structure of a fully glycosylated HIV-1 gp120 core reveals a stabilizing role for the glycan at Asn262

DOE PAGES

Kong, Leopold; Wilson, Ian A.; Kwong, Peter D.

2014-12-26

The crystal structure of a fully glycosylated HIV-1 gp120 core in complex with CD4 receptor and Fab 17b at 4.5-Å resolution reveals 9 of the 15 N-linked glycans of core gp120 to be partially ordered. The glycan at position Asn262 had the most extensive and well-ordered electron density, and a GlcNAc 2Man 7 was modeled. Lastly, the GlcNAc stem of this glycan is largely buried in a cleft in gp120, suggesting a role in gp120 folding and stability. Its arms interact with the stems of neighboring glycans from the oligomannose patch, which is a major target for broadly neutralizing antibodies.

Snapshot of the equilibrium dynamics of a drug bound to HIV-1 reverse transcriptase

NASA Astrophysics Data System (ADS)

Kuroda, Daniel G.; Bauman, Joseph D.; Challa, J. Reddy; Patel, Disha; Troxler, Thomas; Das, Kalyan; Arnold, Eddy; Hochstrasser, Robin M.

2013-03-01

The anti-AIDS drug rilpivirine undergoes conformational changes to bind HIV-1 reverse transcriptase (RT), which is an essential enzyme for the replication of HIV. These changes allow it to retain potency against mutations that otherwise would render the enzyme resistant. Here we report that water molecules play an essential role in this binding process. Femtosecond experiments and theory expose the molecular level dynamics of rilpivirine bound to HIV-1 RT. Two nitrile substituents, one on each arm of the drug, are used as vibrational probes of the structural dynamics within the binding pocket. Two-dimensional vibrational echo spectroscopy reveals that one nitrile group is unexpectedly hydrogen-bonded to a mobile water molecule, not identified in previous X-ray structures. Ultrafast nitrile-water dynamics are confirmed by simulations. A higher (1.51 Å) resolution X-ray structure also reveals a water-drug interaction network. Maintenance of a crucial anchoring hydrogen bond may help retain the potency of rilpivirine against pocket mutations despite the structural variations they cause.

HUBBLE REVEALS THE HEART OF THE WHIRLPOOL GALAXY

NASA Technical Reports Server (NTRS)

2002-01-01

New images from NASA's Hubble Space Telescope are helping researchers view in unprecedented detail the spiral arms and dust clouds of a nearby galaxy, which are the birth sites of massive and luminous stars. The Whirlpool galaxy, M51, has been one of the most photogenic galaxies in amateur and professional astronomy. Easily photographed and viewed by smaller telescopes, this celestial beauty is studied extensively in a range of wavelengths by large ground- and space-based observatories. This Hubble composite image shows visible starlight as well as light from the emission of glowing hydrogen, which is associated with the most luminous young stars in the spiral arms. M51, also known as NGC 5194, is having a close encounter with a nearby companion galaxy, NGC 5195, just off the upper edge of this image. The companion's gravitational pull is triggering star formation in the main galaxy, as seen in brilliant detail by numerous, luminous clusters of young and energetic stars. The bright clusters are highlighted in red by their associated emission from glowing hydrogen gas. This Wide Field Planetary Camera 2 image enables a research group, led by Nick Scoville (Caltech), to clearly define the structure of both the cold dust clouds and the hot hydrogen and link individual clusters to their parent dust clouds. Team members include M. Polletta (U. Geneva); S. Ewald and S. Stolovy (Caltech); R. Thompson and M. Rieke (U. of Arizona). Intricate structure is also seen for the first time in the dust clouds. Along the spiral arms, dust 'spurs' are seen branching out almost perpendicular to the main spiral arms. The regularity and large number of these features suggests to astronomers that previous models of 'two-arm' spiral galaxies may need to be revisited. The new images also reveal a dust disk in the nucleus, which may provide fuel for a nuclear black hole. The team is also studying this galaxy at near-infrared wavelengths with the NICMOS instrument onboard Hubble. At these wavelengths, the dusty clouds are more transparent and the true distribution of stars is more easily seen. In addition, regions of star formation that are obscured in the optical images are newly revealed in the near-infrared images. This image was composed by the Hubble Heritage Team from Hubble archival data of M51 and is superimposed onto ground-based data taken by Travis Rector (NOAO) at the 0.9-meter telescope at the National Science Foundation's Kitt Peak National Observatory (NOAO/AURA) in Tucson, AZ. Image Credit: NASA and The Hubble Heritage Team (STScI/AURA) Acknowledgment: N. Scoville (Caltech) and T. Rector (NOAO)

Genetic interrelations in the actinomycin biosynthetic gene clusters of Streptomyces antibioticus IMRU 3720 and Streptomyces chrysomallus ATCC11523, producers of actinomycin X and actinomycin C

PubMed Central

Crnovčić, Ivana; Rückert, Christian; Semsary, Siamak; Lang, Manuel; Kalinowski, Jörn; Keller, Ullrich

2017-01-01

Sequencing the actinomycin (acm) biosynthetic gene cluster of Streptomyces antibioticus IMRU 3720, which produces actinomycin X (Acm X), revealed 20 genes organized into a highly similar framework as in the bi-armed acm C biosynthetic gene cluster of Streptomyces chrysomallus but without an attached additional extra arm of orthologues as in the latter. Curiously, the extra arm of the S. chrysomallus gene cluster turned out to perfectly match the single arm of the S. antibioticus gene cluster in the same order of orthologues including the the presence of two pseudogenes, scacmM and scacmN, encoding a cytochrome P450 and its ferredoxin, respectively. Orthologues of the latter genes were both missing in the principal arm of the S. chrysomallus acm C gene cluster. All orthologues of the extra arm showed a G +C-contents different from that of their counterparts in the principal arm. Moreover, the similarities of translation products from the extra arm were all higher to the corresponding translation products of orthologue genes from the S. antibioticus acm X gene cluster than to those encoded by the principal arm of their own gene cluster. This suggests that the duplicated structure of the S. chrysomallus acm C biosynthetic gene cluster evolved from previous fusion between two one-armed acm gene clusters each from a different genetic background. However, while scacmM and scacmN in the extra arm of the S. chrysomallus acm C gene cluster are mutated and therefore are non-functional, their orthologues saacmM and saacmN in the S. antibioticus acm C gene cluster show no defects seemingly encoding active enzymes with functions specific for Acm X biosynthesis. Both acm biosynthetic gene clusters lack a kynurenine-3-monooxygenase gene necessary for biosynthesis of 3-hydroxy-4-methylanthranilic acid, the building block of the Acm chromophore, which suggests participation of a genome-encoded relevant monooxygenase during Acm biosynthesis in both S. chrysomallus and S. antibioticus. PMID:28435299

Genetic interrelations in the actinomycin biosynthetic gene clusters of Streptomyces antibioticus IMRU 3720 and Streptomyces chrysomallus ATCC11523, producers of actinomycin X and actinomycin C.

PubMed

Crnovčić, Ivana; Rückert, Christian; Semsary, Siamak; Lang, Manuel; Kalinowski, Jörn; Keller, Ullrich

2017-01-01

Sequencing the actinomycin ( acm ) biosynthetic gene cluster of Streptomyces antibioticus IMRU 3720, which produces actinomycin X (Acm X), revealed 20 genes organized into a highly similar framework as in the bi-armed acm C biosynthetic gene cluster of Streptomyces chrysomallus but without an attached additional extra arm of orthologues as in the latter. Curiously, the extra arm of the S. chrysomallus gene cluster turned out to perfectly match the single arm of the S. antibioticus gene cluster in the same order of orthologues including the the presence of two pseudogenes, scacmM and scacmN , encoding a cytochrome P450 and its ferredoxin, respectively. Orthologues of the latter genes were both missing in the principal arm of the S. chrysomallus acm C gene cluster. All orthologues of the extra arm showed a G +C-contents different from that of their counterparts in the principal arm. Moreover, the similarities of translation products from the extra arm were all higher to the corresponding translation products of orthologue genes from the S. antibioticus acm X gene cluster than to those encoded by the principal arm of their own gene cluster. This suggests that the duplicated structure of the S. chrysomallus acm C biosynthetic gene cluster evolved from previous fusion between two one-armed acm gene clusters each from a different genetic background. However, while scacmM and scacmN in the extra arm of the S. chrysomallus acm C gene cluster are mutated and therefore are non-functional, their orthologues saacmM and saacmN in the S. antibioticus acm C gene cluster show no defects seemingly encoding active enzymes with functions specific for Acm X biosynthesis. Both acm biosynthetic gene clusters lack a kynurenine-3-monooxygenase gene necessary for biosynthesis of 3-hydroxy-4-methylanthranilic acid, the building block of the Acm chromophore, which suggests participation of a genome-encoded relevant monooxygenase during Acm biosynthesis in both S. chrysomallus and S. antibioticus .

Tracing the Arms of our Milky Way Galaxy

NASA Image and Video Library

2015-06-03

Astronomers using data from NASA's Wide-field Infrared Survey Explorer, or WISE, are helping to trace the shape of our Milky Way galaxy's spiral arms. This illustration shows where WISE data revealed clusters of young stars shrouded in dust, called embedded clusters, which are known to reside in spiral arms. The bars represent uncertainties in the data. The nearly 100 clusters shown here were found in the arms called Perseus, Sagittarius-Carina, and Outer -- three of the galaxy's four proposed primary arms. Our sun resides in a spur to an arm, or a minor arm, called Orion Cygnus. http://photojournal.jpl.nasa.gov/catalog/PIA19341

Global enhancement and structure formation of the magnetic field in spiral galaxies

NASA Astrophysics Data System (ADS)

Khoperskov, Sergey A.; Khrapov, Sergey S.

2018-01-01

In this paper we study numerically large-scale magnetic field evolution and its enhancement in gaseous disks of spiral galaxies. We consider a set of models with the various spiral pattern parameters and the initial magnetic field strength with taking into account gas self-gravity and cooling and heating processes. In agreement with previous studies we find out that galactic magnetic field is mostly aligned with gaseous structures, however small-scale gaseous structures (spurs and clumps) are more chaotic than the magnetic field structure. In spiral arms magnetic field often coexists with the gas distribution, in the inter-arm region we see filamentary magnetic field structure. These filaments connect several isolated gaseous clumps. Simulations reveal the presence of the small-scale irregularities of the magnetic field as well as the reversal of magnetic field at the outer edge of the large-scale spurs. We provide evidences that the magnetic field in the spiral arms has a stronger mean-field component, and there is a clear inverse correlation between gas density and plasma-beta parameter, compared to the rest of the disk with a more turbulent component of the field and an absence of correlation between gas density and plasma-beta. We show the mean field growth up to >3-10 μG in the cold gas during several rotation periods (>500-800 Myr), whereas ratio between azimuthal and radial field is equal to >4/1. We find an enhancement of random and ordered components of the magnetic field. Mean field strength increases by a factor of >1.5-2.5 for models with various spiral pattern parameters. Random magnetic field component can reach up to 25% from the total strength. By making an analysis of the time-dependent evolution of the radial Poynting flux, we point out that the magnetic field strength is enhanced more strongly at the galactic outskirts which is due to the radial transfer of magnetic energy by the spiral arms pushing the magnetic field outward. Our results also support the presence of sufficient conditions for the development of magnetorotational instability at distances >11 kpc after >300 Myr of evolution.

Comparative Genome and Proteome Analysis of Anopheles gambiae and Drosophila melanogaster

NASA Astrophysics Data System (ADS)

Zdobnov, Evgeny M.; von Mering, Christian; Letunic, Ivica; Torrents, David; Suyama, Mikita; Copley, Richard R.; Christophides, George K.; Thomasova, Dana; Holt, Robert A.; Subramanian, G. Mani; Mueller, Hans-Michael; Dimopoulos, George; Law, John H.; Wells, Michael A.; Birney, Ewan; Charlab, Rosane; Halpern, Aaron L.; Kokoza, Elena; Kraft, Cheryl L.; Lai, Zhongwu; Lewis, Suzanna; Louis, Christos; Barillas-Mury, Carolina; Nusskern, Deborah; Rubin, Gerald M.; Salzberg, Steven L.; Sutton, Granger G.; Topalis, Pantelis; Wides, Ron; Wincker, Patrick; Yandell, Mark; Collins, Frank H.; Ribeiro, Jose; Gelbart, William M.; Kafatos, Fotis C.; Bork, Peer

2002-10-01

Comparison of the genomes and proteomes of the two diptera Anopheles gambiae and Drosophila melanogaster, which diverged about 250 million years ago, reveals considerable similarities. However, numerous differences are also observed; some of these must reflect the selection and subsequent adaptation associated with different ecologies and life strategies. Almost half of the genes in both genomes are interpreted as orthologs and show an average sequence identity of about 56%, which is slightly lower than that observed between the orthologs of the pufferfish and human (diverged about 450 million years ago). This indicates that these two insects diverged considerably faster than vertebrates. Aligned sequences reveal that orthologous genes have retained only half of their intron/exon structure, indicating that intron gains or losses have occurred at a rate of about one per gene per 125 million years. Chromosomal arms exhibit significant remnants of homology between the two species, although only 34% of the genes colocalize in small ``microsyntenic'' clusters, and major interarm transfers as well as intra-arm shuffling of gene order are detected.

Metallographic examination of the structure of the metal of cold arms of the nineteenth-early twentieth centuries made at the Zlatoust arms factory

NASA Astrophysics Data System (ADS)

Schastlivtsev, V. M.; Rodionov, D. P.; Gerasimov, V. Yu.; Khlebnikova, Yu. V.

2010-11-01

Data are given concerning the structure and the chemical composition of carbon steel used for making cold arms, which was produced at the Zlatoust arms factory in the nineteenth and early twentieth centuries. The results of the analysis of the structure of metal demonstrates the general trend of the development of metallurgy both at the Ural plants and in the world: from the creation of the crucible methods of production of cast steel to the mass production of cast steel by the Bessemer and Martin methods.

Robot arm system for automatic satellite capture and berthing

NASA Technical Reports Server (NTRS)

Nishida, Shinichiro; Toriu, Hidetoshi; Hayashi, Masato; Kubo, Tomoaki; Miyata, Makoto

1994-01-01

Load control is one of the most important technologies for capturing and berthing free flying satellites by a space robot arm because free flying satellites have different motion rates. The performance of active compliance control techniques depend on the location of the force sensor and the arm's structural compliance. A compliance control technique for the robot arm's structural elasticity and a consideration for an end-effector appropriate for it are presented in this paper.

Content and structure of knowledge base used for virtual control of android arm motion in specified environment

NASA Astrophysics Data System (ADS)

Pritykin, F. N.; Nebritov, V. I.

2018-01-01

The paper presents the configuration of knowledge base necessary for intelligent control of android arm mechanism motion with different positions of certain forbidden regions taken into account. The present structure of the knowledge base characterizes the past experience of arm motion synthesis in the vector of velocities with due regard for the known obstacles. This structure also specifies its intrinsic properties. Knowledge base generation is based on the study of the arm mechanism instantaneous states implementations. Computational experiments connected with the virtual control of android arm motion with known forbidden regions using the developed knowledge base are introduced. Using the developed knowledge base to control virtually the arm motion reduces the time of test assignments calculation. The results of the research can be used in developing control systems of autonomous android robots in the known in advance environment.

MC carbide structures in M(lc2)ar-M247. M.S. Thesis - Final Report

NASA Technical Reports Server (NTRS)

Wawro, S. W.

1982-01-01

The morphologies and distribution of the MC carbides in Mar-M247 ingot stock and castings were investigated using metallographic, X-ray diffraction and energy-dispersive X-ray analysis techniques. The MC carbides were found to form script structures during solidification. The script structures were composed of three distinct parts. The central cores and elongated arms of the MC carbide script structures had compositions (Ti, Cr, Hf, Ta, W)C and lattice parameters of 4.39 A. The elongated script arms terminated in enlarged, angular "heads". The heads had compositions (Ti, Hf, Ta, W)C and lattice parameters of approximately 4.50 A. The heads had a higher Hf content than the cores and arms. The size of the script structures, as well as the relative amount of head-type to core and arm-type MC carbide, was found to be determined by solidification conditions. No carryover of the MC carbides from the ingot stock to the remelted and cast material was observed.

A Decade of MWC 758 Disk Images: Where Are the Spiral-arm-driving Planets?

NASA Astrophysics Data System (ADS)

Ren, Bin; Dong, Ruobing; Esposito, Thomas M.; Pueyo, Laurent; Debes, John H.; Poteet, Charles A.; Choquet, Élodie; Benisty, Myriam; Chiang, Eugene; Grady, Carol A.; Hines, Dean C.; Schneider, Glenn; Soummer, Rémi

2018-04-01

Large-scale spiral arms have been revealed in scattered light images of a few protoplanetary disks. Theoretical models suggest that such arms may be driven by and corotate with giant planets, which has called for remarkable observational efforts to look for them. By examining the rotation of the spiral arms for the MWC 758 system over a 10 year timescale, we are able to provide dynamical constraints on the locations of their perturbers. We present reprocessed Hubble Space Telescope (HST)/NICMOS F110W observations of the target in 2005, and the new Keck/NIRC2 L‧-band observations in 2017. MWC 758's two well-known spiral arms are revealed in the NICMOS archive at the earliest observational epoch. With additional Very Large Telescope (VLT)/SPHERE data, our joint analysis leads to a pattern speed of 0\\buildrel{\\circ}\\over{.} {6}-0\\buildrel{\\circ\\over{.} 6}+3\\buildrel{\\circ\\over{.} 3} {yr}}-1 at 3σ for the two major spiral arms. If the two arms are induced by a perturber on a near-circular orbit, its best-fit orbit is at 89 au (0.″59), with a 3σ lower limit of 30 au (0.″20). This finding is consistent with the simulation prediction of the location of an arm-driving planet for the two major arms in the system.

Small supernumerary marker chromosome derived from proximal p-arm of chromosome 2: identification by fluorescent in situ hybridization.

PubMed

Lasan Trcić, Ruzica; Hitrec, Vlasta; Letica, Ljiljana; Cuk, Mario; Begović, Davor

2003-08-01

Conventional cytogenetics detected an interstitial deletion of proximal region of p-arm of chromosome 2 in a 6-month-old boy with a phenotype slightly resembling Down's syndrome. The deletion was inherited from the father, whose karyotype revealed a small ring-shaped marker chromosome, in addition to interstitial deletion. Fluorescence in situ hybridization identified the marker, which consisted of the proximal region of the p-arm of chromosome 2, including a part of its centromere. This case shows that molecular cytogenetic analysis can reveal the mechanism of the formation of the marker chromosome.

Load emphasizes muscle effort minimization during selection of arm movement direction

PubMed Central

2012-01-01

Background Directional preferences during center-out horizontal shoulder-elbow movements were previously established for both the dominant and non-dominant arm with the use of a free-stroke drawing task that required random selection of movement directions. While the preferred directions were mirror-symmetrical in both arms, they were attributed to a tendency specific for the dominant arm to simplify control of interaction torque by actively accelerating one joint and producing largely passive motion at the other joint. No conclusive evidence has been obtained in support of muscle effort minimization as a contributing factor to the directional preferences. Here, we tested whether distal load changes directional preferences, making the influence of muscle effort minimization on the selection of movement direction more apparent. Methods The free-stroke drawing task was performed by the dominant and non-dominant arm with no load and with 0.454 kg load at the wrist. Motion of each arm was limited to rotation of the shoulder and elbow in the horizontal plane. Directional histograms of strokes produced by the fingertip were calculated to assess directional preferences in each arm and load condition. Possible causes for directional preferences were further investigated by studying optimization across directions of a number of cost functions. Results Preferences in both arms to move in the diagonal directions were revealed. The previously suggested tendency to actively accelerate one joint and produce passive motion at the other joint was supported in both arms and load conditions. However, the load increased the tendency to produce strokes in the transverse diagonal directions (perpendicular to the forearm orientation) in both arms. Increases in required muscle effort caused by the load suggested that the higher frequency of movements in the transverse directions represented increased influence of muscle effort minimization on the selection of movement direction. This interpretation was supported by cost function optimization results. Conclusions While without load, the contribution of muscle effort minimization was minor, and therefore, not apparent, the load revealed this contribution by enhancing it. Unlike control of interaction torque, the revealed tendency to minimize muscle effort was independent of arm dominance. PMID:23035925

Chlamydomonas DYX1C1/PF23 is essential for axonemal assembly and proper morphology of inner dynein arms

PubMed Central

Yamamoto, Ryosuke; Alford, Lea M.; Ide, Takahiro; Owa, Mikito; Hwang, Juyeon; Inaba, Kazuo; James, Noliyanda; Ishikawa, Takashi

2017-01-01

Cytoplasmic assembly of ciliary dyneins, a process known as preassembly, requires numerous non-dynein proteins, but the identities and functions of these proteins are not fully elucidated. Here, we show that the classical Chlamydomonas motility mutant pf23 is defective in the Chlamydomonas homolog of DYX1C1. The pf23 mutant has a 494 bp deletion in the DYX1C1 gene and expresses a shorter DYX1C1 protein in the cytoplasm. Structural analyses, using cryo-ET, reveal that pf23 axonemes lack most of the inner dynein arms. Spectral counting confirms that DYX1C1 is essential for the assembly of the majority of ciliary inner dynein arms (IDA) as well as a fraction of the outer dynein arms (ODA). A C-terminal truncation of DYX1C1 shows a reduction in a subset of these ciliary IDAs. Sucrose gradients of cytoplasmic extracts show that preassembled ciliary dyneins are reduced compared to wild-type, which suggests an important role in dynein complex stability. The role of PF23/DYX1C1 remains unknown, but we suggest that DYX1C1 could provide a scaffold for macromolecular assembly. PMID:28892495

Clues to the Formation of Spiral Structure in M51 from the Ages and Locations of Star Clusters

NASA Astrophysics Data System (ADS)

Chandar, Rupali; Chien, L.-H.; Meidt, Sharon; Querejeta, Miguel; Dobbs, Clare; Schinnerer, Eva; Whitmore, Bradley C.; Calzetti, Daniela; Dinino, Daiana; Kennicutt, Robert C.; Regan, Michael

2017-08-01

We determine the spatial distributions of star clusters at different ages in the grand-design spiral galaxy M51 using a new catalog based on multi-band images taken with the Hubble Space Telescope (HST). These distributions, when compared with the spiral structure defined by molecular gas, dust, young and old stars, show the following sequence in the inner arms: dense molecular gas (and dust) defines the inner edge of the spiral structure, followed by an overdensity of old stars and then young stellar clusters. The offset between gas and young clusters in the inner arms is consistent with the expectations for a density wave. Clusters as old as a few hundred Myr remain concentrated close to the spiral arms, although the distributions are broader than those for the youngest clusters, which is also consistent with predictions from density wave simulations. The outermost portion of the west arm is different from the rest of the spiral structure in that it contains primarily intermediate-age (≈ 100{--}400 {Myr}) clusters; we believe that this is a “material” arm. We have identified four “feathers,” stellar structures beyond the inner arms that have a larger pitch angle than the arms. We do not find age gradients along any of the feathers, but the least coherent feathers appear to have the largest range of cluster ages.

Physical cryptographic verification of nuclear warheads

PubMed Central

Kemp, R. Scott; Danagoulian, Areg; Macdonald, Ruaridh R.; Vavrek, Jayson R.

2016-01-01

How does one prove a claim about a highly sensitive object such as a nuclear weapon without revealing information about the object? This paradox has challenged nuclear arms control for more than five decades. We present a mechanism in the form of an interactive proof system that can validate the structure and composition of an object, such as a nuclear warhead, to arbitrary precision without revealing either its structure or composition. We introduce a tomographic method that simultaneously resolves both the geometric and isotopic makeup of an object. We also introduce a method of protecting information using a provably secure cryptographic hash that does not rely on electronics or software. These techniques, when combined with a suitable protocol, constitute an interactive proof system that could reject hoax items and clear authentic warheads with excellent sensitivity in reasonably short measurement times. PMID:27432959

Physical cryptographic verification of nuclear warheads

NASA Astrophysics Data System (ADS)

Kemp, R. Scott; Danagoulian, Areg; Macdonald, Ruaridh R.; Vavrek, Jayson R.

2016-08-01

How does one prove a claim about a highly sensitive object such as a nuclear weapon without revealing information about the object? This paradox has challenged nuclear arms control for more than five decades. We present a mechanism in the form of an interactive proof system that can validate the structure and composition of an object, such as a nuclear warhead, to arbitrary precision without revealing either its structure or composition. We introduce a tomographic method that simultaneously resolves both the geometric and isotopic makeup of an object. We also introduce a method of protecting information using a provably secure cryptographic hash that does not rely on electronics or software. These techniques, when combined with a suitable protocol, constitute an interactive proof system that could reject hoax items and clear authentic warheads with excellent sensitivity in reasonably short measurement times.

Physical cryptographic verification of nuclear warheads.

PubMed

Kemp, R Scott; Danagoulian, Areg; Macdonald, Ruaridh R; Vavrek, Jayson R

2016-08-02

How does one prove a claim about a highly sensitive object such as a nuclear weapon without revealing information about the object? This paradox has challenged nuclear arms control for more than five decades. We present a mechanism in the form of an interactive proof system that can validate the structure and composition of an object, such as a nuclear warhead, to arbitrary precision without revealing either its structure or composition. We introduce a tomographic method that simultaneously resolves both the geometric and isotopic makeup of an object. We also introduce a method of protecting information using a provably secure cryptographic hash that does not rely on electronics or software. These techniques, when combined with a suitable protocol, constitute an interactive proof system that could reject hoax items and clear authentic warheads with excellent sensitivity in reasonably short measurement times.

Design considerations for an astronaut monorail system for large space structures and the structural characterization of its positioning arm

NASA Astrophysics Data System (ADS)

Watson, Judith J.

1992-08-01

An astronaut monorail system (AMS) is presented as a vehicle to transport and position EVA astronauts along large space truss structures. The AMS is proposed specifically as an alternative to the crew and equipment transfer aid for Space Station Freedom. Design considerations for the AMS were discussed and a reference configuration was selected for the study. Equations were developed to characterize the stiffness and frequency behavior of the AMS positioning arm. Experimental data showed that these equations gave a fairly accurate representation of the stiffness and frequency behavior of the arm. A study was presented to show trends for the arm behavior based on varying parameters of the stiffness and frequency equations. An ergonomics study was conducted to provide boundary conditions for tolerable frequency and deflection to be used in developing a design concept for the positioning arm. The feasibility of the AMS positioning arm was examined using equations and working curves developed in this study. It was found that a positioning arm of a length to reach all interior points of the space station truss structure could not be designed to satisfy frequency and deflection constraints. By relaxing the design requirements and the ergonomic boundaries, an arm could be designed which would provide a stable work platform for the EVA astronaut and give him access to over 75 percent of the truss interior.

Functional morphology of comminuting feeding structures of Trichodactylus borellianus (Brachyura, Decapoda, Trichodactylidae), an omnivorous freshwater crab.

PubMed

Carvalho, Débora de Azevedo; Viozzi, Maria Florencia; Collins, Pablo Agustín; Williner, Verónica

2017-07-01

Crustaceans exhibit great diversity of feeding structures with morphological traits that are useful to infer the general trophic habits of species. In this study, we analyzed the functional morphology of comminuting feeding structures (mandibles, chelipeds, gastric mill) of the freshwater crab Trichodactylus borellianus directly related with the food fragmentation. The heterochely and mechanical advantage (MA) of the chelae were also studied. In both analyses, we considered the relationship between morphology and the natural diet. We expected to find a consistent relation between feeding habits and morphological traits. In general, we found simple structures armed with uniform setal systems and feeding appendages without pronounced teeth or spines. Mandibles have primarily cutting functions, helping with the food anchoring and fragmentation with mandibular palps armed with pappose setae. Chelipeds were covered with spines and simple setae. Adult males exhibited right-handedness with high MA of the major chelae. The ingested, relatively large pieces of food are finally chewed by a gastric mill equipped with sharp cusps characteristic of decapods with low ingestion of crude fiber material. The morphology of the feeding apparatus revealed that it is well adapted to an omnivorous diet, being able to cope with dietary changes. Copyright © 2017 Elsevier Ltd. All rights reserved.

The MIA complex is a conserved and novel dynein regulator essential for normal ciliary motility

PubMed Central

Yamamoto, Ryosuke; Song, Kangkang; Yanagisawa, Haru-aki; Fox, Laura; Yagi, Toshiki; Wirschell, Maureen; Hirono, Masafumi; Kamiya, Ritsu; Nicastro, Daniela

2013-01-01

Axonemal dyneins must be precisely regulated and coordinated to produce ordered ciliary/flagellar motility, but how this is achieved is not understood. We analyzed two Chlamydomonas reinhardtii mutants, mia1 and mia2, which display slow swimming and low flagellar beat frequency. We found that the MIA1 and MIA2 genes encode conserved coiled-coil proteins, FAP100 and FAP73, respectively, which form the modifier of inner arms (MIA) complex in flagella. Cryo–electron tomography of mia mutant axonemes revealed that the MIA complex was located immediately distal to the intermediate/light chain complex of I1 dynein and structurally appeared to connect with the nexin–dynein regulatory complex. In axonemes from mutants that lack both the outer dynein arms and the MIA complex, I1 dynein failed to assemble, suggesting physical interactions between these three axonemal complexes and a role for the MIA complex in the stable assembly of I1 dynein. The MIA complex appears to regulate I1 dynein and possibly outer arm dyneins, which are both essential for normal motility. PMID:23569216

Altered Gene Regulation and Synaptic Morphology in "Drosophila" Learning and Memory Mutants

ERIC Educational Resources Information Center

Guan, Zhuo; Buhl, Lauren K.; Quinn, William G.; Littleton, J. Troy

2011-01-01

Genetic studies in "Drosophila" have revealed two separable long-term memory pathways defined as anesthesia-resistant memory (ARM) and long-lasting long-term memory (LLTM). ARM is disrupted in "radish" ("rsh") mutants, whereas LLTM requires CREB-dependent protein synthesis. Although the downstream effectors of ARM and LLTM are distinct, pathways…

Crystal Structure of FadA Adhesin from Fusobacterium nucleatum Reveals a Novel Oligomerization Motif, the Leucine Chain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nithianantham, Stanley; Xu, Minghua; Yamada, Mitsunori

2009-04-07

Many bacterial appendages have filamentous structures, often composed of repeating monomers assembled in a head-to-tail manner. The mechanisms of such linkages vary. We report here a novel protein oligomerization motif identified in the FadA adhesin from the Gram-negative bacterium Fusobacterium nucleatum. The 2.0 {angstrom} crystal structure of the secreted form of FadA (mFadA) reveals two antiparallel {alpha}-helices connected by an intervening 8-residue hairpin loop. Leucine-leucine contacts play a prominent dual intra- and intermolecular role in the structure and function of FadA. First, they comprise the main association between the two helical arms of the monomer; second, they mediate the head-to-tailmore » association of monomers to form the elongated polymers. This leucine-mediated filamentous assembly of FadA molecules constitutes a novel structural motif termed the 'leucine chain.' The essential role of these residues in FadA is corroborated by mutagenesis of selected leucine residues, which leads to the abrogation of oligomerization, filament formation, and binding to host cells.« less

Ergonomically neutral arm support system

DOEpatents

Siminovitch, Michael J; Chung, Jeffrey Y; Dellinges, Steven; Lafever, Robin E

2005-08-02

An ergonomic arm support system maintains a neutral position for the forearm. A mechanical support structure attached to a chair or other mounting structure supports the arms of a sitting or standing person. The system includes moving elements and tensioning elements to provide a dynamic balancing force against the forearms. The support structure is not fixed or locked in a rigid position, but is an active dynamic system that is maintained in equipoise by the continuous operation of the opposing forces. The support structure includes an armrest connected to a flexible linkage or articulated or pivoting assembly, which includes a tensioning element such as a spring. The pivoting assembly moves up and down, with the tensioning element providing the upward force that balances the downward force of the arm.

Sequence Composition and Gene Content of the Short Arm of Rye (Secale cereale) Chromosome 1

PubMed Central

Fluch, Silvia; Kopecky, Dieter; Burg, Kornel; Šimková, Hana; Taudien, Stefan; Petzold, Andreas; Kubaláková, Marie; Platzer, Matthias; Berenyi, Maria; Krainer, Siegfried; Doležel, Jaroslav; Lelley, Tamas

2012-01-01

Background The purpose of the study is to elucidate the sequence composition of the short arm of rye chromosome 1 (Secale cereale) with special focus on its gene content, because this portion of the rye genome is an integrated part of several hundreds of bread wheat varieties worldwide. Methodology/Principal Findings Multiple Displacement Amplification of 1RS DNA, obtained from flow sorted 1RS chromosomes, using 1RS ditelosomic wheat-rye addition line, and subsequent Roche 454FLX sequencing of this DNA yielded 195,313,589 bp sequence information. This quantity of sequence information resulted in 0.43× sequence coverage of the 1RS chromosome arm, permitting the identification of genes with estimated probability of 95%. A detailed analysis revealed that more than 5% of the 1RS sequence consisted of gene space, identifying at least 3,121 gene loci representing 1,882 different gene functions. Repetitive elements comprised about 72% of the 1RS sequence, Gypsy/Sabrina (13.3%) being the most abundant. More than four thousand simple sequence repeat (SSR) sites mostly located in gene related sequence reads were identified for possible marker development. The existence of chloroplast insertions in 1RS has been verified by identifying chimeric chloroplast-genomic sequence reads. Synteny analysis of 1RS to the full genomes of Oryza sativa and Brachypodium distachyon revealed that about half of the genes of 1RS correspond to the distal end of the short arm of rice chromosome 5 and the proximal region of the long arm of Brachypodium distachyon chromosome 2. Comparison of the gene content of 1RS to 1HS barley chromosome arm revealed high conservation of genes related to chromosome 5 of rice. Conclusions The present study revealed the gene content and potential gene functions on this chromosome arm and demonstrated numerous sequence elements like SSRs and gene-related sequences, which can be utilised for future research as well as in breeding of wheat and rye. PMID:22328922

Global Modeling of Spur Formation in Spiral Galaxies

NASA Astrophysics Data System (ADS)

Shetty, Rahul; Ostriker, Eve C.

2006-08-01

We investigate the formation of substructure in spiral galaxies using global MHD simulations, including gas self-gravity. Local modeling by Kim & Ostriker previously showed that self-gravity and magnetic fields cause rapid growth of overdensities in spiral arms; differential compression of gas flowing through the arms then results in the formation of sheared structures in the interarms. These sheared structures resemble features described as spurs or feathers in optical and IR observations of many spiral galaxies. Global modeling extends previous local models by including the full effects of curvilinear coordinates, a realistic log-spiral perturbation, self-gravitational contribution from five radial wavelengths of the spiral shock, and variation of density and epicyclic frequency with radius. We show that with realistic Toomre Q-values self-gravity and galactic differential rotation produce filamentary gaseous structures with kiloparsec-scale separations, regardless of the strength-or even presence-of a stellar spiral potential. However, a sufficiently strong spiral potential is required to produce true spurs, consisting of interarm structures emerging from gas concentrations in the main spiral arms. In models where Q is initially constant, filaments due to interarm self-gravity grow mainly in the outer regions, whereas true arm spurs grow only in the inner regions. For models with Q~R, outer regions are intrinsically more stable, so background interarm filaments do not grow, but arm spurs can develop if the spiral potential is strong. Unlike independently growing background filaments, the orientation of arm spurs depends on galactic location. Inside corotation, spurs emanate outward, on the convex side of the arm; outside corotation, spurs grow inward, on the concave side of the arm. Based on orientation and the relation to arm clumps, it is possible to distinguish true spurs that originate as instabilities in the arms from independently growing background filaments. We measure spur spacings of ~3-5 times the Jeans length in the arm and arm clump masses of ~107 Msolar. Finally, we have also studied models without self-gravity, finding that magnetic fields suppress a purely hydrodynamic instability recently proposed by Wada & Koda as a means of growing interarm spurs and feathers. Our models also suggest that magnetic fields are important in preserving grand-design spiral structure when gas in the arms fragments via self-gravity into GMCs.

Sample size determinations for group-based randomized clinical trials with different levels of data hierarchy between experimental and control arms.

PubMed

Heo, Moonseong; Litwin, Alain H; Blackstock, Oni; Kim, Namhee; Arnsten, Julia H

2017-02-01

We derived sample size formulae for detecting main effects in group-based randomized clinical trials with different levels of data hierarchy between experimental and control arms. Such designs are necessary when experimental interventions need to be administered to groups of subjects whereas control conditions need to be administered to individual subjects. This type of trial, often referred to as a partially nested or partially clustered design, has been implemented for management of chronic diseases such as diabetes and is beginning to emerge more commonly in wider clinical settings. Depending on the research setting, the level of hierarchy of data structure for the experimental arm can be three or two, whereas that for the control arm is two or one. Such different levels of data hierarchy assume correlation structures of outcomes that are different between arms, regardless of whether research settings require two or three level data structure for the experimental arm. Therefore, the different correlations should be taken into account for statistical modeling and for sample size determinations. To this end, we considered mixed-effects linear models with different correlation structures between experimental and control arms to theoretically derive and empirically validate the sample size formulae with simulation studies.

A novel subunit structure of Clostridium botulinum serotype D toxin complex with three extended arms.

PubMed

Hasegawa, Kimiko; Watanabe, Toshihiro; Suzuki, Tomonori; Yamano, Akihito; Oikawa, Tetsuo; Sato, Yasuhiko; Kouguchi, Hirokazu; Yoneyama, Tohru; Niwa, Koichi; Ikeda, Toshihiko; Ohyama, Tohru

2007-08-24

The botulinum neurotoxins (BoNTs) are the most potent toxins known in nature, causing the lethal disease known as botulism in humans and animals. The BoNTs act by inhibiting neurotransmitter release from cholinergic synapses. Clostridium botulinum strains produce large BoNTs toxin complexes, which include auxiliary non-toxic proteins that appear not only to protect BoNTs from the hostile environment of the digestive tract but also to assist BoNT translocation across the intestinal mucosal layer. In this study, we visualize for the first time a series of botulinum serotype D toxin complexes using negative stain transmission electron microscopy (TEM). The complexes consist of the 150-kDa BoNT, 130-kDa non-toxic non-hemagglutinin (NTNHA), and three kinds of hemagglutinin (HA) subcomponents: 70-kDa HA-70, 33-kDa HA-33, and 17-kDa HA-17. These components assemble sequentially to form the complex. A novel TEM image of the mature L-TC revealed an ellipsoidal-shaped structure with "three arms" attached. The "body" section was comprised of a single BoNT, a single NTNHA and three HA-70 molecules. The arm section consisted of a complex of HA-33 and HA-17 molecules. We determined the x-ray crystal structure of the complex formed by two HA-33 plus one HA-17. On the basis of the TEM image and biochemical results, we propose a novel 14-mer subunit model for the botulinum toxin complex. This unique model suggests how non-toxic components make up a "delivery vehicle" for BoNT.

Star formation and ISM morphology in tidally induced spiral structures

NASA Astrophysics Data System (ADS)

Pettitt, Alex R.; Tasker, Elizabeth J.; Wadsley, James W.; Keller, Ben W.; Benincasa, Samantha M.

2017-07-01

Tidal encounters are believed to be one of the key drivers of galactic spiral structure in the Universe. Such spirals are expected to produce different morphological and kinematic features compared to density wave and dynamic spiral arms. In this work, we present high-resolution simulations of a tidal encounter of a small mass companion with a disc galaxy. Included are the effects of gas cooling and heating, star formation and stellar feedback. The structure of the perturbed disc differs greatly from the isolated galaxy, showing clear spiral features that act as sites of new star formation, and displaying interarm spurs. The two arms of the galaxy, the bridge and tail, appear to behave differently; with different star formation histories and structure. Specific attention is focused on offsets between gas and stellar spiral features which can be directly compared to observations. We find that some offsets do exist between different media, with gaseous arms appearing mostly on the convex side of the stellar arms, though the exact locations appear highly time dependent. These results further highlight the differences between tidal spirals and other theories of arm structure.

Airfoil-Shaped Fluid Flow Tool for Use in Making Differential Measurements

NASA Technical Reports Server (NTRS)

England, John Dwight (Inventor); Kelley, Anthony R. (Inventor); Cronise, Raymond J. (Inventor)

2014-01-01

A fluid flow tool includes an airfoil structure and a support arm. The airfoil structure's high-pressure side and low-pressure side are positioned in a conduit by the support arm coupled to the conduit. The high-pressure and low-pressure sides substantially face opposing walls of the conduit. At least one measurement port is formed in the airfoil structure at each of its high-pressure side and low-pressure side. A first manifold, formed in the airfoil structure and in fluid communication with each measurement port so-formed at the high-pressure side, extends through the airfoil structure and support arm to terminate and be accessible at the exterior wall of the conduit. A second manifold, formed in the airfoil structure and in fluid communication with each measurement port so-formed at the low-pressure side, extends through the airfoil structure and support arm to terminate and be accessible at the exterior wall of the conduit.

Clinical comparison of automatic, noninvasive measurements of blood pressure in the forearm and upper arm with the patient supine or with the head of the bed raised 45 degrees: a follow-up study.

PubMed

Schell, Kathleen; Lyons, Denise; Bradley, Elisabeth; Bucher, Linda; Seckel, Maureen; Wakai, Sandra; Carson, Elizabeth; Waterhouse, Julie; Chichester, Melanie; Bartell, Deborah; Foraker, Theresa; Simpson, E Kathleen

2006-03-01

Noninvasive measurement of blood pressure in the forearm is used when the upper arm is inaccessible and/or when available blood pressure cuffs do not fit a patient's arm. Evidence supporting this practice is limited. To compare noninvasive measurements of blood pressure in the forearm and upper arm of medical-surgical inpatients positioned supine and with the head of the bed raised 45 degrees . Cuff size was selected on the basis of forearm and upper arm circumference and manufacturers' recommendations. With a Welch Allyn Vital Signs 420 Series monitor, blood pressures were measured in the forearm and then in the upper arm of 221 supine patients with their arms resting at their sides. Patients were repositioned with the head of the bed elevated 45 degrees and after 2 minutes, blood pressures were measured in the upper arm and then the forearm. Starting position was alternated on subsequent subjects. Paired t tests revealed significant differences between systolic and diastolic blood pressures measured in the upper arm and forearm with patients supine and with the head of the bed elevated 45 degrees . The Bland-Altman procedure revealed that the distances between the mean values and the limits of agreement were from 15 to 33 mm Hg for individual subjects. Noninvasive measurements of blood pressure in the forearm and upper arm cannot be interchanged in medical-surgical patients who are supine or in patients with the head of the bed elevated 45 degrees .

Sequential Versus Concurrent Trastuzumab in Adjuvant Chemotherapy for Breast Cancer

PubMed Central

Perez, Edith A.; Suman, Vera J.; Davidson, Nancy E.; Gralow, Julie R.; Kaufman, Peter A.; Visscher, Daniel W.; Chen, Beiyun; Ingle, James N.; Dakhil, Shaker R.; Zujewski, JoAnne; Moreno-Aspitia, Alvaro; Pisansky, Thomas M.; Jenkins, Robert B.

2011-01-01

Purpose NCCTG (North Central Cancer Treatment Group) N9831 is the only randomized phase III trial evaluating trastuzumab added sequentially or used concurrently with chemotherapy in resected stages I to III invasive human epidermal growth factor receptor 2–positive breast cancer. Patients and Methods Patients received doxorubicin and cyclophosphamide every 3 weeks for four cycles, followed by paclitaxel weekly for 12 weeks (arm A), paclitaxel plus sequential trastuzumab weekly for 52 weeks (arm B), or paclitaxel plus concurrent trastuzumab for 12 weeks followed by trastuzumab for 40 weeks (arm C). The primary end point was disease-free survival (DFS). Results Comparison of arm A (n = 1,087) and arm B (n = 1,097), with 6-year median follow-up and 390 events, revealed 5-year DFS rates of 71.8% and 80.1%, respectively. DFS was significantly increased with trastuzumab added sequentially to paclitaxel (log-rank P < .001; arm B/arm A hazard ratio [HR], 0.69; 95% CI, 0.57 to 0.85). Comparison of arm B (n = 954) and arm C (n = 949), with 6-year median follow-up and 313 events, revealed 5-year DFS rates of 80.1% and 84.4%, respectively. There was an increase in DFS with concurrent trastuzumab and paclitaxel relative to sequential administration (arm C/arm B HR, 0.77; 99.9% CI, 0.53 to 1.11), but the P value (.02) did not cross the prespecified O'Brien-Fleming boundary (.00116) for the interim analysis. Conclusion DFS was significantly improved with 52 weeks of trastuzumab added to adjuvant chemotherapy. On the basis of a positive risk-benefit ratio, we recommend that trastuzumab be incorporated into a concurrent regimen with taxane chemotherapy as an important standard-of-care treatment alternative to a sequential regimen. PMID:22042958

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du, Xinyu; Xu, Ye; Yang, Ji

Using the Purple Mountain Observatory Delingha (PMODLH) 13.7 m telescope, we report a 96 deg{sup 2} {sup 12}CO/{sup 13}CO/C{sup 18}O mapping observation toward the Galactic region of l  = [139.°75,149.°75], b  = [−5.°25, 5.°25]. The molecular structures of the Local Arm and Perseus Arm are presented. Combining H i data and part of the Outer Arm results, we obtain that the warp structure of both atomic and molecular gas is obvious, while the flare structure only exists in atomic gas in this observing region. In addition, five filamentary giant molecular clouds on the Perseus Arm are identified. Among them, four are newlymore » identified. Their relations with the Milky Way large-scale structure are discussed.« less

Analysis of Nidogen-1/Laminin γ1 Interaction by Cross-Linking, Mass Spectrometry, and Computational Modeling Reveals Multiple Binding Modes

PubMed Central

Lössl, Philip; Kölbel, Knut; Tänzler, Dirk; Nannemann, David; Ihling, Christian H.; Keller, Manuel V.; Schneider, Marian; Zaucke, Frank; Meiler, Jens; Sinz, Andrea

2014-01-01

We describe the detailed structural investigation of nidogen-1/laminin γ1 complexes using full-length nidogen-1 and a number of laminin γ1 variants. The interactions of nidogen-1 with laminin variants γ1 LEb2–4, γ1 LEb2–4 N836D, γ1 short arm, and γ1 short arm N836D were investigated by applying a combination of (photo-)chemical cross-linking, high-resolution mass spectrometry, and computational modeling. In addition, surface plasmon resonance and ELISA studies were used to determine kinetic constants of the nidogen-1/laminin γ1 interaction. Two complementary cross-linking strategies were pursued to analyze solution structures of laminin γ1 variants and nidogen-1. The majority of distance information was obtained with the homobifunctional amine-reactive cross-linker bis(sulfosuccinimidyl)glutarate. In a second approach, UV-induced cross-linking was performed after incorporation of the diazirine-containing unnatural amino acids photo-leucine and photo-methionine into laminin γ1 LEb2–4, laminin γ1 short arm, and nidogen-1. Our results indicate that Asn-836 within laminin γ1 LEb3 domain is not essential for complex formation. Cross-links between laminin γ1 short arm and nidogen-1 were found in all protein regions, evidencing several additional contact regions apart from the known interaction site. Computational modeling based on the cross-linking constraints indicates the existence of a conformational ensemble of both the individual proteins and the nidogen-1/laminin γ1 complex. This finding implies different modes of interaction resulting in several distinct protein-protein interfaces. PMID:25387007

Marker chromosome genomic structure and temporal origin implicate a chromoanasynthesis event in a family with pleiotropic psychiatric phenotypes.

PubMed

Grochowski, Christopher M; Gu, Shen; Yuan, Bo; Tcw, Julia; Brennand, Kristen J; Sebat, Jonathan; Malhotra, Dheeraj; McCarthy, Shane; Rudolph, Uwe; Lindstrand, Anna; Chong, Zechen; Levy, Deborah L; Lupski, James R; Carvalho, Claudia M B

2018-04-25

Small supernumerary marker chromosomes (sSMC) are chromosomal fragments difficult to characterize genomically. Here, we detail a proband with schizoaffective disorder and a mother with bipolar disorder with psychotic features who present with a marker chromosome that segregates with disease. We explored the architecture of this marker and investigated its temporal origin. Array comparative genomic hybridization (aCGH) analysis revealed three duplications and three triplications that spanned the short arm of chromosome 9, suggestive of a chromoanasynthesis-like event. Segregation of marker genotypes, phased using sSMC mosaicism in the mother, provided evidence that it was generated during a germline-level event in the proband's maternal grandmother. Whole-genome sequencing (WGS) was performed to resolve the structure and junctions of the chromosomal fragments, revealing further complexities. While structural variations have been previously associated with neuropsychiatric disorders and marker chromosomes, here we detail the precise architecture, human life-cycle genesis, and propose a DNA replicative/repair mechanism underlying formation. © 2018 Wiley Periodicals, Inc.

Computer-assisted image analysis of human cilia and Chlamydomonas flagella reveals both similarities and differences in axoneme structure.

PubMed

O'Toole, Eileen T; Giddings, Thomas H; Porter, Mary E; Ostrowski, Lawrence E

2012-08-01

In the past decade, investigations from several different fields have revealed the critical role of cilia in human health and disease. Because of the highly conserved nature of the basic axonemal structure, many different model systems have proven useful for the study of ciliopathies, especially the unicellular, biflagellate green alga Chlamydomonas reinhardtii. Although the basic axonemal structure of cilia and flagella is highly conserved, these organelles often perform specialized functions unique to the cell or tissue in which they are found. These differences in function are likely reflected in differences in structural organization. In this work, we directly compare the structure of isolated axonemes from human cilia and Chlamydomonas flagella to identify similarities and differences that potentially play key roles in determining their functionality. Using transmission electron microscopy and 2D image averaging techniques, our analysis has confirmed the overall structural similarity between these two species, but also revealed clear differences in the structure of the outer dynein arms, the central pair projections, and the radial spokes. We also show how the application of 2D image averaging can clarify the underlying structural defects associated with primary ciliary dyskinesia (PCD). Overall, our results document the remarkable similarity between these two structures separated evolutionarily by over a billion years, while highlighting several significant differences, and demonstrate the potential of 2D image averaging to improve the diagnosis and understanding of PCD. Copyright © 2012 Wiley Periodicals, Inc.

Structural and biophysical properties of h-FANCI ARM repeat protein.

PubMed

Siddiqui, Mohd Quadir; Choudhary, Rajan Kumar; Thapa, Pankaj; Kulkarni, Neha; Rajpurohit, Yogendra S; Misra, Hari S; Gadewal, Nikhil; Kumar, Satish; Hasan, Syed K; Varma, Ashok K

2017-11-01

Fanconi anemia complementation groups - I (FANCI) protein facilitates DNA ICL (Inter-Cross-link) repair and plays a crucial role in genomic integrity. FANCI is a 1328 amino acids protein which contains armadillo (ARM) repeats and EDGE motif at the C-terminus. ARM repeats are functionally diverse and evolutionarily conserved domain that plays a pivotal role in protein-protein and protein-DNA interactions. Considering the importance of ARM repeats, we have explored comprehensive in silico and in vitro approach to examine folding pattern. Size exclusion chromatography, dynamic light scattering (DLS) and glutaraldehyde crosslinking studies suggest that FANCI ARM repeat exist as monomer as well as in oligomeric forms. Circular dichroism (CD) and fluorescence spectroscopy results demonstrate that protein has predominantly α- helices and well-folded tertiary structure. DNA binding was analysed using electrophoretic mobility shift assay by autoradiography. Temperature-dependent CD, Fluorescence spectroscopy and DLS studies concluded that protein unfolds and start forming oligomer from 30°C. The existence of stable portion within FANCI ARM repeat was examined using limited proteolysis and mass spectrometry. The normal mode analysis, molecular dynamics and principal component analysis demonstrated that helix-turn-helix (HTH) motif present in ARM repeat is highly dynamic and has anti-correlated motion. Furthermore, FANCI ARM repeat has HTH structural motif which binds to double-stranded DNA.

A novel method for quantifying arm motion similarity.

PubMed

Zhi Li; Hauser, Kris; Roldan, Jay Ryan; Milutinovic, Dejan; Rosen, Jacob

2015-08-01

This paper proposes a novel task-independent method for quantifying arm motion similarity that can be applied to any kinematic/dynamic variable of interest. Given two arm motions for the same task, not necessarily with the same completion time, it plots the time-normalized curves against one another and generates four real-valued features. To validate these features we apply them to quantify the relationship between healthy and paretic arm motions of chronic stroke patients. Studying both unimanual and bimanual arm motions of eight chronic stroke patients, we find that inter-arm coupling that tends to synchronize the motions of both arms in bimanual motions, has a stronger effect at task-relevant joints than at task-irrelevant joints. It also revealed that the paretic arm suppresses the shoulder flexion of the non-paretic arm, while the latter encourages the shoulder rotation of the former.

Physical cryptographic verification of nuclear warheads

DOE PAGES

Kemp, R. Scott; Danagoulian, Areg; Macdonald, Ruaridh R.; ...

2016-07-18

How does one prove a claim about a highly sensitive object such as a nuclear weapon without revealing information about the object? This paradox has challenged nuclear arms control for more than five decades. We present a mechanism in the form of an interactive proof system that can validate the structure and composition of an object, such as a nuclear warhead, to arbitrary precision without revealing either its structure or composition. We introduce a tomographic method that simultaneously resolves both the geometric and isotopic makeup of an object. We also introduce a method of protecting information using a provably securemore » cryptographic hash that does not rely on electronics or software. Finally, these techniques, when combined with a suitable protocol, constitute an interactive proof system that could reject hoax items and clear authentic warheads with excellent sensitivity in reasonably short measurement times.« less

Synthesis, structure and antimicrobial evaluation of a new gossypol triazole conjugates functionalized with aliphatic chains and benzyloxy groups.

PubMed

Pyta, Krystian; Blecha, Marietta; Janas, Anna; Klich, Katarzyna; Pecyna, Paulina; Gajecka, Marzena; Przybylski, Piotr

2016-09-01

Synthetic limitations in the copper-catalyzed azide alkyne cycloaddition (CuAAC) on gossypol's skeleton functionalized with alkyne (2) or azide (3) groups have been indicated. Modified approach to the synthesis of new gossypol-triazole conjugates yielded new compounds (24-31) being potential fungicides. Spectroscopic studies of triazole conjugates 24-31 have revealed their structures in solution, i.e., the presence of enamine-enamine tautomeric forms and π-π stacking intramolecular interactions between triazole arms. Biological evaluation of the new gossypol-triazole conjugates revealed the potency of 30 and 31 derivatives, having triazole-benzyloxy moieties, comparable with that of miconazole against Fusarium oxysporum. The results of HPLC evaluation of ergosterol content in different fungi strains upon treatment of gossypol and its derivatives enabled to propose a mechanism of antifungal activity of these compounds. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fatigue Resistant Design Criteria for MD SHA Cantilevered Mast Arm Signal Structure

DOT National Transportation Integrated Search

2017-12-01

The fatigue design of the mast arm structures and connections vary significantly based on the Category of Importance factor adopted and the load cases for fatigue design loads. Consideration should include the cost and size of the structures for both...

Endophilin-A1 BAR domain interaction with arachidonyl CoA.

PubMed

Petoukhov, Maxim V; Weissenhorn, Winfried; Svergun, Dmitri I

2014-01-01

Endophilin-A1 belongs to the family of BAR domain containing proteins that catalyze membrane remodeling processes via sensing, inducing and stabilizing membrane curvature. We show that the BAR domain of endophilin-A1 binds arachidonic acid and molds its coenzyme A (CoA) activated form, arachidonyl-CoA into a defined structure. We studied low resolution structures of endophilin-A1-BAR and its complex with arachidonyl-CoA in solution using synchrotron small-angle X-ray scattering (SAXS). The free endophilin-A1-BAR domain is shown to be dimeric at lower concentrations but builds tetramers and higher order complexes with increasing concentrations. Extensive titration SAXS studies revealed that the BAR domain produces a homogenous complex with the lipid micelles. The structural model of the complexes revealed two arachidonyl-CoA micelles bound to the distal arms of an endophilin-A1-BAR dimer. Intriguingly, the radius of the bound micelles significantly decreases compared to that of the free micelles, and this structural result may provide hints on the potential biological relevance of the endophilin-A1-BAR interaction with arachidonyl CoA.

Hand to Mouth in a Neandertal: Right-Handedness in Regourdou 1

PubMed Central

Volpato, Virginie; Macchiarelli, Roberto; Guatelli-Steinberg, Debbie; Fiore, Ivana; Bondioli, Luca; Frayer, David W.

2012-01-01

We describe and analyze a Neandertal postcranial skeleton and dentition, which together show unambiguous signs of right-handedness. Asymmetries between the left and right upper arm in Regourdou 1 were identified nearly 20 years ago, then confirmed by more detailed analyses of the inner bone structure for the clavicle, humerus, radius and ulna. The total pattern of all bones in the shoulder and arm reveals that Regourdou 1 was a right-hander. Confirmatory evidence comes from the mandibular incisors, which display a distinct pattern of right oblique scratches, typical of right-handed manipulations performed at the front of the mouth. Regourdou's right handedness is consistent with the strong pattern of manual lateralization in Neandertals and further confirms a modern pattern of left brain dominance, presumably signally linguistic competence. These observations along with cultural, genetic and morphological evidence indicate language competence in Neandertals and their European precursors. PMID:22937134

Private sector involvement in times of armed conflict: What are the constraints for trading medical equipment?

PubMed

Schmidt, Georg

Today, healthcare facilities are highly dependent on the private sector to keep their medical equipment functioning. Moreover, private sector involvement becomes particularly important for the supply of spare parts and consumables. However, in times of armed conflict, the capacity of the corporate world appears to be seriously hindered. Subsequently, this study researches the influence of armed conflict on the private medical equipment sector. This study follows a qualitative approach by conducting 19 interviews with representatives of the corporate world in an active conflict zone. A semistructured interview guide, consisting of 10 questions, was used to examine the constraints of this sector. The results reveal that the lack of skilled personnel, complicated importation procedures, and a decrease in financial capacity are the major constraints faced by private companies dealing in medical equipment in conflict zones. Even when no official sanctions and embargoes for medical items exist, constraints for trading medical equipment are clearly recognizable. Countries at war would benefit from a centralized structure that deals with the importation procedures for medical items, to assist local companies in their purchasing procedures. A high degree of adaption is needed to continue operating, despite the emerging constraints of armed conflict. Future studies might research the constraints for manufacturers outside the conflict to export medical items to the country of war.

A simple integrated ratiometric wavelength monitor based on multimode interference structure

NASA Astrophysics Data System (ADS)

Hatta, Agus Muhamad; Farrell, Gerald; Wang, Qian

2008-09-01

Wavelength measurement or monitoring can be implemented using a ratiometric power measurement technique. A ratiometric wavelength monitor normally consists of a Y-branch splitter with two arms: an edge filter arm with a well defined spectral response and a reference arm or alternatively, two edge filters arms with opposite slope spectral responses. In this paper, a simple configuration for an integrated ratiometric wavelength monitor based on a single multimode interference structure is proposed. By optimizing the length of the MMI and the two output port positions, opposite spectral responses for the two output ports can be achieved. The designed structure demonstrates a spectral response suitable for wavelength measurement with potentially a 10 pm resolution over a 100 nm wavelength range.

Study of design and control of remote manipulators. Modeling manipulator arms with distributed flexibility for design and control

NASA Technical Reports Server (NTRS)

Book, W. J.

1974-01-01

The interactions of control system and distributed flexible structural dynamics is explored for mechanical arms. A modeling process using 4 x 4 transfer matrices is described which permits the closed loop response of many current arm configurations to be evaluated. Root locus, frequency response, modal shapes, and time impulse response have all been obtained from the digital computer implementation of this model, which is oriented to arm design and allows for easy variation of the arm configuration through data cards. The model corresponds with experimentally observed natural frequencies with an average error of less than 5% in the first three flexible modes in the seven cases considered. The model was used to explore the limits imposed by structural flexibility on a nondimensionalized two link arm with one and two joints for planar motion.

Dense cores of GMAs in M51

NASA Astrophysics Data System (ADS)

Egusa, Fumi; Koda, J.; Scoville, N. Z.

2010-01-01

We present sensitive and high angular resolution CO(1-0) data obtained by CARMA observations toward the nearby grand-design spiral galaxy M51. From the data, Giant Molecular Associations (GMAs) in a spiral arm are found to be resolved into a few small clumps with mass of 106 Msun and size of 40 pc. As the densities of these clumps are estimated to be larger than 300 cm-3, we regard them as dense cores of GMAs. If GMAs were just confusion of Giant Molecular Clouds (GMCs) whose typical mass and size are almost the same as those of the detected clumps, we should have detected tens or more of them per each GMA considering the sensitivity of our data. However, only one or two cores are found in each GMA, indicating that GMAs are not ensembles of GMCs but are discrete smooth structures. This result is consistent with the conclusion by Koda et al. (2009), who worked on lower resolution CO data of M51. In addition, we have found that these cores are located downstream of the spiral arm. This suggests that the core formation of GMAs and their evolution are triggered by the spiral structure, or density waves. Our high resolution data reveal the inner structure of GMAs and its relationships to the global structure for the first time in grand-design spiral galaxies.

The Orbit of the Companion to HD 100453A: Binary-driven Spiral Arms in a Protoplanetary Disk

NASA Astrophysics Data System (ADS)

Wagner, Kevin; Dong, Ruobing; Sheehan, Patrick; Apai, Dániel; Kasper, Markus; McClure, Melissa; Morzinski, Katie M.; Close, Laird; Males, Jared; Hinz, Phil; Quanz, Sascha P.; Fung, Jeffrey

2018-02-01

HD 100453AB is a 10 ± 2 Myr old binary whose protoplanetary disk was recently revealed to host a global two-armed spiral structure. Given the relatively small projected separation of the binary (1.″05, or ∼108 au), gravitational perturbations by the binary seemed to be a likely driving force behind the formation of the spiral arms. However, the orbit of these stars remained poorly understood, which prevented a proper treatment of the dynamical influence of the companion on the disk. We observed HD 100453AB between 2015 and 2017, utilizing extreme adaptive optics systems on the Very Large Telescope and the Magellan Clay Telescope. We combined the astrometry from these observations with published data to constrain the parameters of the binary’s orbit to a = 1.″06 ± 0.″09, e = 0.17±0.07, and i = 32.°5 ± 6.°5. We utilized publicly available ALMA 12CO data to constrain the inclination of the disk, {i}{{disk}}∼ 28^\\circ , which is relatively coplanar with the orbit of the companion and consistent with previous estimates from scattered light images. Finally, we input these constraints into hydrodynamic and radiative transfer simulations to model the structural evolution of the disk. We find that the spiral structure and truncation of the circumprimary disk in HD 100453 are consistent with a companion-driven origin. Furthermore, we find that the primary star’s rotation, its outer disk, and the companion exhibit roughly the same direction of angular momentum, and thus the system likely formed from the same parent body of material.

Effect of Knudsen thermal force on the performance of low-pressure micro gas sensor

NASA Astrophysics Data System (ADS)

Barzegar Gerdroodbary, M.; Ganji, D. D.; Taeibi-Rahni, M.; Vakilipour, Shidvash

2017-07-01

In this paper, Direct Simulation Monte Carlo (DSMC) simulations were applied to investigate the mechanism of the force generation inside a low-pressure gas sensor. The flow feature and force generation mechanism inside a rectangular enclosure with heat and cold arms as the non-isothermal walls are comprehensively explained. In addition, extensive parametric studies are done to study the effects of physical parameters on the performance and characteristics of this device in different operating conditions. In this research, the Knudsen number is varied from 0.1 to 4.5 (0.5 to 11torr) to reveal all the characteristics of the thermally driven force inside the MEMS sensor. In order to simulate a rarefied gas inside the micro gas detector, Boltzmann equations are applied to obtain high-precision results. The effects of ambient pressure and temperature difference of arms are comprehensively investigated. Our findings show that maximum force increases more than 7 times when the temperature difference of the cold and hot arms is increased from 10 to 100K. In addition, the results demonstrate that the thermal gradient at rarefied pressure induces complex structure, and the mechanism of force generation highly varies at different pressure conditions.

Hubble peeks at a spiral galaxy

NASA Image and Video Library

2015-07-10

This little-known galaxy, officially named J04542829-6625280, but most often referred to as LEDA 89996, is a classic example of a spiral galaxy. The galaxy is much like our own galaxy, the Milky Way. The disk-shaped galaxy is seen face on, revealing the winding structure of the spiral arms. Dark patches in these spiral arms are in fact dust and gas — the raw materials for new stars. The many young stars that form in these regions make the spiral arms appear bright and bluish. The galaxy sits in a vibrant area of the night sky within the constellation of Dorado (The Swordfish), and appears very close to the Large Magellanic Cloud — one of the satellite galaxies of the Milky Way. The observations were carried out with the high resolution channel of Hubble’s Advanced Camera for Surveys. Image credit: ESA/Hubble & NASA, Acknowledgement: Flickr user C. Claude NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Galaxy with a view

NASA Image and Video Library

2015-07-06

This little-known galaxy, officially named J04542829-6625280, but most often referred to as LEDA 89996, is a classic example of a spiral galaxy. The galaxy is much like our own galaxy, the Milky Way. The disc-shaped galaxy is seen face on, revealing the winding structure of the spiral arms. Dark patches in these spiral arms are in fact dust and gas — the raw materials for new stars. The many young stars that form in these regions make the spiral arms appear bright and bluish. The galaxy sits in a vibrant area of the night sky within the constellation of Dorado (The Swordfish), and appears very close to the Large Magellanic Cloud  — one of the satellite galaxies of the Milky Way. The observations were carried out with the high resolution channel of Hubble’s Advanced Camera for Surveys. This instrument has delivered some of the sharpest views of the Universe so far achieved by mankind. This image covers only a tiny patch of sky — about the size of a one cent euro coin held 100 metres away! A version of this image was entered into the Hubble’s Hidden Treasures image processing competition by flickr user c.claude.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baba, Junichi; Saitoh, Takayuki R.; Wada, Keiichi, E-mail: babajn@geo.titech.ac.jp

In order to understand the physical mechanisms underlying non-steady stellar spiral arms in disk galaxies, we analyzed the growing and damping phases of their spiral arms using three-dimensional N-body simulations. We confirmed that the spiral arms are formed due to a swing amplification mechanism that reinforces density enhancement as a seeded wake. In the damping phase, the Coriolis force exerted on a portion of the arm surpasses the gravitational force that acts to shrink the portion. Consequently, the stars in the portion escape from the arm, and subsequently they form a new arm at a different location. The time-dependent naturemore » of the spiral arms originates in the continual repetition of this nonlinear phenomenon. Since a spiral arm does not rigidly rotate, but follows the galactic differential rotation, the stars in the arm rotate at almost the same rate as the arm. In other words, every single position in the arm can be regarded as the corotation point. Due to interaction with their host arms, the energy and angular momentum of the stars change, thereby causing radial migration of the stars. During this process, the kinetic energy of random motion (random energy) of the stars does not significantly increase, and the disk remains dynamically cold. Owing to this low degree of disk heating, short-lived spiral arms can recurrently develop over many rotational periods. The resultant structure of the spiral arms in the N-body simulations is consistent with the observational nature of spiral galaxies. We conclude that the formation and structure of spiral arms in isolated disk galaxies can be reasonably understood by nonlinear interactions between a spiral arm and its constituent stars.« less

Synchrotron X-ray scattering characterization of the molecular structures of star polystyrenes with varying numbers of arms.

PubMed

Jin, Sangwoo; Higashihara, Tomoya; Jin, Kyeong Sik; Yoon, Jinhwan; Rho, Yecheol; Ahn, Byungcheol; Kim, Jehan; Hirao, Akira; Ree, Moonhor

2010-05-20

We have synthesized well-defined multiarmed star polystyrenes, with 6, 9, 17, 33, and 57 arms, and studied their molecular shapes and structural characteristics in a good solvent (tetrahydrofuran at 25 degrees C) and in a theta (Theta) solvent (cyclohexane at 35 degrees C) by small-angle X-ray scattering (SAXS) using a synchrotron radiation source. Analysis of the SAXS data provided a detailed characterization of the molecular shapes, including the contributions of the blob morphology of the arms, the radius of gyration, the paired distance distribution, the radial electron density distribution, and the Zimm-Stockmayer and Roovers g-factor, for the multiarmed star polystyrenes. In particular, the molecular shapes of the star polystyrenes were found to change from a fuzzy ellipsoid, for the 6-armed polystyrene, to a fuzzy sphere, for the 57-armed polystyrene, with an increasing number of arms. The ellipsoidal character of the star polystyrenes with fewer arms may originate from the extended anisotropically branched architecture at the center of the molecule. The arms of the star polystyrenes were found to be more extended than those of the linear polystyrenes. Furthermore, the degree of chain extension in the arms increased with the number of arms.

Our Milky Way Gets a Makeover

NASA Technical Reports Server (NTRS)

2008-01-01

[figure removed for brevity, see original site] [figure removed for brevity, see original site] Click on image for Fully Annotated Version Click on image for Poster Version

Like early explorers mapping the continents of our globe, astronomers are busy charting the spiral structure of our galaxy, the Milky Way. Using infrared images from NASA's Spitzer Space Telescope, scientists have discovered that the Milky Way's elegant spiral structure is dominated by just two arms wrapping off the ends of a central bar of stars. Previously, our galaxy was thought to possess four major arms.

This artist's concept illustrates the new view of the Milky Way, along with other findings presented at the 212th American Astronomical Society meeting in St. Louis, Mo. The galaxy's two major arms (Scutum-Centaurus and Perseus) can be seen attached to the ends of a thick central bar, while the two now-demoted minor arms (Norma and Sagittarius) are less distinct and located between the major arms. The major arms consist of the highest densities of both young and old stars; the minor arms are primarily filled with gas and pockets of star-forming activity.

The artist's concept also includes a new spiral arm, called the 'Far-3 kiloparsec arm,' discovered via a radio-telescope survey of gas in the Milky Way. This arm is shorter than the two major arms and lies along the bar of the galaxy.

Our sun lies near a small, partial arm called the Orion Arm, or Orion Spur, located between the Sagittarius and Perseus arms.

How do octopuses use their arms?

PubMed

Mather, J A

1998-09-01

A taxonomy of the movement patterns of the 8 flexible arms of octopuses is constructed. Components consist of movements of the arm itself, the ventral suckers and their stalks, as well as the relative position of arms and the skin web between them. Within 1 arm, combinations of components result in a variety of behaviors. At the level of all arms, 1 group of behaviors is described as postures, on the basis of the spread of all arms and the web to make a 2-dimensional surface whose position differs in the 3rd dimension. Another group of arm behaviors is actions, more or less coordinated and involving several to all arms. Arm control appears to be based on radial symmetry, relative equipotentiality of all arms, relative independence of each arm, and separability of components within the arm. The types and coordination of arm behaviors are discussed with relationship to biomechanical limits, muscle structures, and neuronal programming.

Dietary Intake Influences Adult Fertility and Offspring Fitness in Zebrafish.

PubMed

Newman, Trent; Jhinku, Noel; Meier, Michael; Horsfield, Julia

2016-01-01

The burden of malnutrition, including both over- and undernutrition, is a major public health concern. Here we used a zebrafish model of diet-induced obesity to analyze the impact of dietary intake on fertility and the phenotype of the next generation. Over an eight-week period, one group received 60 mg of food each day (60 mg arm), while another received 5 mg (5 mg arm). At the end of the diet, the body mass index of the 60 mg arm was 1.5 fold greater than the 5 mg arm. The intervention also had a marked impact on fertility; breeding success and egg production in the 60 mg arm were increased 2.1- and 6.2-fold compared to the 5 mg arm, respectively. Transcriptome analysis of eggs revealed that transcripts involved in metabolic biological processes differed according to dietary intake. The progeny from the differentially fed fish were more likely to survive when the parents had access to more food. An intergenerational crossover study revealed that while parental diet did not influence weight gain in the offspring, the progeny of well-fed parents had increased levels of physical activity when exposed again to high nutrient availability. We conclude that dietary intake has an important influence on fertility and the subsequent fitness of offspring, even prior to breeding.

Dietary Intake Influences Adult Fertility and Offspring Fitness in Zebrafish

PubMed Central

Jhinku, Noel; Meier, Michael; Horsfield, Julia

2016-01-01

The burden of malnutrition, including both over- and undernutrition, is a major public health concern. Here we used a zebrafish model of diet-induced obesity to analyze the impact of dietary intake on fertility and the phenotype of the next generation. Over an eight-week period, one group received 60 mg of food each day (60 mg arm), while another received 5 mg (5 mg arm). At the end of the diet, the body mass index of the 60 mg arm was 1.5 fold greater than the 5 mg arm. The intervention also had a marked impact on fertility; breeding success and egg production in the 60 mg arm were increased 2.1- and 6.2-fold compared to the 5 mg arm, respectively. Transcriptome analysis of eggs revealed that transcripts involved in metabolic biological processes differed according to dietary intake. The progeny from the differentially fed fish were more likely to survive when the parents had access to more food. An intergenerational crossover study revealed that while parental diet did not influence weight gain in the offspring, the progeny of well-fed parents had increased levels of physical activity when exposed again to high nutrient availability. We conclude that dietary intake has an important influence on fertility and the subsequent fitness of offspring, even prior to breeding. PMID:27870856

On the nature of motor planning variables during arm pointing movement: Compositeness and speed dependence.

PubMed

Vu, Van Hoan; Isableu, Brice; Berret, Bastien

2016-07-22

The purpose of this study was to investigate the nature of the variables and rules underlying the planning of unrestrained 3D arm reaching. To identify whether the brain uses kinematic, dynamic and energetic values in an isolated manner or combines them in a flexible way, we examined the effects of speed variations upon the chosen arm trajectories during free arm movements. Within the optimal control framework, we uncovered which (possibly composite) optimality criterion underlays at best the empirical data. Fifteen participants were asked to perform free-endpoint reaching movements from a specific arm configuration at slow, normal and fast speeds. Experimental results revealed that prominent features of observed motor behaviors were significantly speed-dependent, such as the chosen reach endpoint and the final arm posture. Nevertheless, participants exhibited different arm trajectories and various degrees of speed dependence of their reaching behavior. These inter-individual differences were addressed using a numerical inverse optimal control methodology. Simulation results revealed that a weighted combination of kinematic, energetic and dynamic cost functions was required to account for all the critical features of the participants' behavior. Furthermore, no evidence for the existence of a speed-dependent tuning of these weights was found, thereby suggesting subject-specific but speed-invariant weightings of kinematic, energetic and dynamic variables during the motor planning process of free arm movements. This suggested that the inter-individual difference of arm trajectories and speed dependence was not only due to anthropometric singularities but also to critical differences in the composition of the subjective cost function. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

The onset of spiral structure in the universe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elmegreen, Debra Meloy; Elmegreen, Bruce G.

2014-01-20

The onset of spiral structure in galaxies appears to occur between redshifts 1.4 and 1.8 when disks have developed a cool stellar component, rotation dominates over turbulent motions in the gas, and massive clumps become less frequent. During the transition from clumpy to spiral disks, two unusual types of spirals are found in the Hubble Ultra Deep Field that are massive, clumpy, and irregular like their predecessor clumpy disks, yet spiral-like or sheared like their descendants. One type is 'woolly' with massive clumpy arms all over the disk and is brighter than other disk galaxies at the same redshift, whilemore » another type has irregular multiple arms with high pitch angles, star formation knots, and no inner symmetry like today's multiple-arm galaxies. The common types of spirals seen locally are also present in a redshift range around z ∼ 1, namely grand design with two symmetric arms, multiple arm with symmetry in the inner parts and several long, thin arms in the outer parts, and flocculent, with short, irregular, and patchy arms that are mostly from star formation. Normal multiple-arm galaxies are found only closer than z ∼ 0.6 in the Ultra Deep Field. Grand design galaxies extend furthest to z ∼ 1.8, presumably because interactions can drive a two-arm spiral in a disk that would otherwise have a more irregular structure. The difference between these types is understandable in terms of the usual stability parameters for gas and stars, and the ratio of the velocity dispersion to rotation speed.« less

Full-scale investigation of wind-induced vibrations of mast-arm traffic signal structures.

DOT National Transportation Integrated Search

2014-08-01

Because of their inherent : fl : exibility and low damping ratios, cantilevered mast : - : arm : tra : ffi : c signal structures are suscepti : b : le to : wind : - : induced vibrations. : These vibrations : cause stru : ctural stresses and strains t...

Design and testing of a model CELSS chamber robot

NASA Astrophysics Data System (ADS)

Davis, Mark; Dezego, Shawn; Jones, Kinzy; Kewley, Christopher; Langlais, Mike; McCarthy, John; Penny, Damon; Bonner, Tom; Funderburke, C. Ashley; Hailey, Ruth

1994-08-01

A robot system for use in an enclosed environment was designed and tested. The conceptual design will be used to assist in research performed by the Controlled Ecological Life Support System (CELSS) project. Design specifications include maximum load capacity, operation at specified environmental conditions, low maintenance, and safety. The robot system must not be hazardous to the sealed environment, and be capable of stowing and deploying within a minimum area of the CELSS chamber facility. This design consists of a telescoping robot arm that slides vertically on a shaft positioned in the center of the CELSS chamber. The telescoping robot arm consists of a series of links which can be fully extended to a length equal to the radius of the working envelope of the CELSS chamber. The vertical motion of the robot arm is achieved through the use of a combination ball screw/ball spline actuator system. The robot arm rotates cylindrically about the vertical axis through use of a turntable bearing attached to a central mounting structure fitted to the actuator shaft. The shaft is installed in an overhead rail system allowing the entire structure to be stowed and deployed within the CELSS chamber. The overhead rail system is located above the chamber's upper lamps and extends to the center of the CELSS chamber. The mounting interface of the actuator shaft and rail system allows the entire actuator shaft to be detached and removed from the CELSS chamber. When the actuator shaft is deployed, it is held fixed at the bottom of the chamber by placing a square knob on the bottom of the shaft into a recessed square fitting in the bottom of the chamber floor. A support boot ensures the rigidity of the shaft. Three student teams combined into one group designed a model of the CELSS chamber robot that they could build. They investigated materials, availability, and strength in their design. After the model arm and stand were built, the class performed pre-tests on the entire system. A stability pre-test was used to determine whether the model robot arm would tip over on the stand when it was fully extended. Results showed the stand tipped when 50 Newtons were applied horizontally to the top of the vertical shaft while the arm was fully extended.

Design and testing of a model CELSS chamber robot

NASA Technical Reports Server (NTRS)

Davis, Mark; Dezego, Shawn; Jones, Kinzy; Kewley, Christopher; Langlais, Mike; Mccarthy, John; Penny, Damon; Bonner, Tom; Funderburke, C. Ashley; Hailey, Ruth

1994-01-01

A robot system for use in an enclosed environment was designed and tested. The conceptual design will be used to assist in research performed by the Controlled Ecological Life Support System (CELSS) project. Design specifications include maximum load capacity, operation at specified environmental conditions, low maintenance, and safety. The robot system must not be hazardous to the sealed environment, and be capable of stowing and deploying within a minimum area of the CELSS chamber facility. This design consists of a telescoping robot arm that slides vertically on a shaft positioned in the center of the CELSS chamber. The telescoping robot arm consists of a series of links which can be fully extended to a length equal to the radius of the working envelope of the CELSS chamber. The vertical motion of the robot arm is achieved through the use of a combination ball screw/ball spline actuator system. The robot arm rotates cylindrically about the vertical axis through use of a turntable bearing attached to a central mounting structure fitted to the actuator shaft. The shaft is installed in an overhead rail system allowing the entire structure to be stowed and deployed within the CELSS chamber. The overhead rail system is located above the chamber's upper lamps and extends to the center of the CELSS chamber. The mounting interface of the actuator shaft and rail system allows the entire actuator shaft to be detached and removed from the CELSS chamber. When the actuator shaft is deployed, it is held fixed at the bottom of the chamber by placing a square knob on the bottom of the shaft into a recessed square fitting in the bottom of the chamber floor. A support boot ensures the rigidity of the shaft. Three student teams combined into one group designed a model of the CELSS chamber robot that they could build. They investigated materials, availability, and strength in their design. After the model arm and stand were built, the class performed pre-tests on the entire system. A stability pre-test was used to determine whether the model robot arm would tip over on the stand when it was fully extended. Results showed the stand tipped when 50 Newtons were applied horizontally to the top of the vertical shaft while the arm was fully extended. This proved that it was stable. Another pre-test was the actuator slip test used to determine if there is an adequate coefficient of friction between the actuator drive wheels and drive cable to enable the actuator to fully extend and retract the arm. This pre-test revealed that the coefficient of friction was not large enough to prevent slippage. Sandpaper was glued to the drive wheel and this eliminated the slippage problem. The class preformed a fit test in the CELSS chamber to ensure that the completed robot arm is capable of reaching the entire working envelope. The robot was centered in the chamber and the arm was fully extended to the sides of the chamber. The arm was also able to retract to clear the drain pipes separating the upper and lower plant trays.

A four-way junction with triple-helical arms: design, characterization, and stability.

PubMed

Makube, N; Klump, H H

2000-05-01

The formation of the four-way junction containing four triple-helical arms has been demonstrated using chemical methods (polyacrylamide gel electrophoresis and chemical footprinting using OsO(4) as a probe) and physical methods (UV absorbance melting and DSC). The junction J(T1T3) was assembled from two 20-mer purine strands and two 44-mer pyrimidine strands. To determine the contribution of the different arms to the stability of the complete structure of J(T1T3), the junction was compared to two simplified substructures, J(T1) and J(T3), respectively. Common to these complexes is the underlying double-helical four-way junction Js. Addition of Na(+) had a profound effect on stabilizing and subsequently folding the junctions into the stacked X-structures. The following results support the structure present: (i) The native polyacrylamide electrophoresis exhibits only a single band(s) corresponding to one species present when all four single strands are mixed in equal amounts. (ii) OsO(4) modifications were investigated at pH 5.0 and in the presence of 10 mM Mg(2+) and 100 mM Na(+). There is no cleavage of thymine residues at the branch point and throughout the structure. (iii) The thermal unfolding of J(T1) and J(T3) illustrates that the triple-helical arms are more stable than the double-helical arms which are contained in these junctions and that J(T1T3) with four triple-helical arms is slightly more stable than J(T1) and J(T3). (iv) The calorimetric transition enthalpies determined for the arms of J(T1T3) are comparable to those associated with the unfolding of its corresponding arms in J(T1) and J(T3). The results also illustrate that the formation of the junctions is not restricted by the pH, [Na(+)], sequence composition of the arms, and/or the loop position. Copyright 2000 Academic Press.

Cryo-scanning electron microscopy investigation of the Octopus Vulgaris arm structures for the design of an octopus-like arm artefact.

PubMed

Minnocci, Antonio; Cianchetti, Matteo; Mazzolai, Barbara; Sebastiani, Luca; Laschi, Cecilia

2015-12-01

Octopus vulgaris is a cephalopod of the Octopodidae family. It has four pairs of arms and two rows of suckers which perform many functions, including bending and elongation. For this reason the octopus was chosen as model to develop a new generation of soft-body robots. In order to explain some of the fine structures of the octopus arm in relation to its specific ability, we examined the external and internal structures of O. vulgaris arms in a frozen-hydrated state using cryo-scanning electron microscopy. The arms showed skin with a very complex design that is useful to elongation, and a pore pattern distribution on their surface which is functional to cutaneous oxygen uptake. The analysis of freeze-fractured frozen-hydrated arm samples allowed us to describe the developmental differences in the relative proportion of the areas of axial nerve cord, intrinsic and extrinsic musculature, in relation to the growth of the arms and of the increase in functional capability. In the suckers, we analyzed the shedding mechanisms in the outer part of the infundibulum and described the outer and inner characteristics of the denticles, showing in detail their pore system, which is fundamental for their ability to explore the environment. These results are discussed by considering their possible application in the design of new octopus-like artefacts, which will be able to take advantage of some of these ultrastructure characteristics and achieve advanced bioinspired functionalities. © 2015 Wiley Periodicals, Inc.

Distinct roles of 1α and 1β heavy chains of the inner arm dynein I1 of Chlamydomonas flagella

PubMed Central

Toba, Shiori; Fox, Laura A.; Sakakibara, Hitoshi; Porter, Mary E.; Oiwa, Kazuhiro; Sale, Winfield S.

2011-01-01

The Chlamydomonas I1 dynein is a two-headed inner dynein arm important for the regulation of flagellar bending. Here we took advantage of mutant strains lacking either the 1α or 1β motor domain to distinguish the functional role of each motor domain. Single- particle electronic microscopic analysis confirmed that both the I1α and I1β complexes are single headed with similar ringlike, motor domain structures. Despite similarity in structure, however, the I1β complex has severalfold higher ATPase activity and microtubule gliding motility compared to the I1α complex. Moreover, in vivo measurement of microtubule sliding in axonemes revealed that the loss of the 1β motor results in a more severe impairment in motility and failure in regulation of microtubule sliding by the I1 dynein phosphoregulatory mechanism. The data indicate that each I1 motor domain is distinct in function: The I1β motor domain is an effective motor required for wild-type microtubule sliding, whereas the I1α motor domain may be responsible for local restraint of microtubule sliding. PMID:21148301

KSC-08pd0671

NASA Image and Video Library

2008-03-10

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 39A at NASA's Kennedy Space Center, rollback of the rotating service structure reveals space shuttle Endeavour atop the mobile launcher platform. First motion was at 8:23 a.m. and rollback was complete at 8:55 a.m. Above the orange external tank is seen the "beanie cap" at the end of the gaseous oxygen vent arm, extending from the fixed service structure. Vapors are created as the liquid oxygen in the external tank boil off. The hood vents the gaseous oxygen vapors away from the space shuttle vehicle. Below is the orbiter access arm with the White Room at the end, flush against the shuttle. The crew gains access into the orbiter through the White Room. On either side of the main engines and below the wings are the tail service masts, which provide several umbilical connections to the orbiter, including a liquid-oxygen line through one and a liquid-hydrogen line through another. The rotating structure provides protected access to the orbiter for changeout and servicing of payloads at the pad. The structure is supported by a rotating bridge that pivots about a vertical axis on the west side of the pad's flame trench. After the RSS is rolled back, the orbiter is ready for fuel cell activation and external tank cryogenic propellant loading operations. The pad is cleared to the perimeter gate for operations to fill the external tank with about 500,000 gallons of cryogenic propellants used by the shuttle’s main engines. This is done at the pad approximately eight hours before the scheduled launch. Endeavour and its crew will deliver the first section of the Japan Aerospace Exploration Agency's Kibo laboratory and the Canadian Space Agency's two-armed robotic system, Dextre. Launch is scheduled for 2:28 a.m. EDT March 11. Photo credit: NASA/Kim Shiflett

KSC-08pd0670

NASA Image and Video Library

2008-03-10

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 39A at NASA's Kennedy Space Center, rollback of the rotating service structure (at left) reveals space shuttle Endeavour atop the mobile launcher platform. First motion was at 8:23 a.m. and rollback was complete at 8:55 a.m. Above the orange external tank is seen the "beanie cap" at the end of the gaseous oxygen vent arm, extending from the fixed service structure. Vapors are created as the liquid oxygen in the external tank boil off. The hood vents the gaseous oxygen vapors away from the space shuttle vehicle. Below is the orbiter access arm with the White Room at the end, flush against the shuttle. The crew gains access into the orbiter through the White Room. On either side of the main engines and below the wings are the tail service masts, which provide several umbilical connections to the orbiter, including a liquid-oxygen line through one and a liquid-hydrogen line through another. The rotating structure provides protected access to the orbiter for changeout and servicing of payloads at the pad. The structure is supported by a rotating bridge that pivots about a vertical axis on the west side of the pad's flame trench. After the RSS is rolled back, the orbiter is ready for fuel cell activation and external tank cryogenic propellant loading operations. The pad is cleared to the perimeter gate for operations to fill the external tank with about 500,000 gallons of cryogenic propellants used by the shuttle’s main engines. This is done at the pad approximately eight hours before the scheduled launch. Endeavour and its crew will deliver the first section of the Japan Aerospace Exploration Agency's Kibo laboratory and the Canadian Space Agency's two-armed robotic system, Dextre. Launch is scheduled for 2:28 a.m. EDT March 11. Photo credit: NASA/Kim Shiflett

Structure of a headful DNA-packaging bacterial virus at 2.9 Å resolution by electron cryo-microscopy

PubMed Central

Zhao, Haiyan; Li, Kunpeng; Lynn, Anna Y.; Aron, Keith E.; Yu, Guimei; Jiang, Wen; Tang, Liang

2017-01-01

The enormous prevalence of tailed DNA bacteriophages on this planet is enabled by highly efficient self-assembly of hundreds of protein subunits into highly stable capsids. These capsids can stand with an internal pressure as high as ∼50 atmospheres as a result of the phage DNA-packaging process. Here we report the complete atomic model of the headful DNA-packaging bacteriophage Sf6 at 2.9 Å resolution determined by electron cryo-microscopy. The structure reveals the DNA-inflated, tensed state of a robust protein shell assembled via noncovalent interactions. Remarkable global conformational polymorphism of capsid proteins, a network formed by extended N arms, mortise-and-tenon–like intercapsomer joints, and abundant β-sheet–like mainchain:mainchain intermolecular interactions, confers significant strength yet also flexibility required for capsid assembly and DNA packaging. Differential formations of the hexon and penton are mediated by a drastic α–helix-to-β–strand structural transition. The assembly scheme revealed here may be common among tailed DNA phages and herpesviruses. PMID:28320961

Research regarding the influence of driving-wires length change on positioning precision of a robotic arm

NASA Astrophysics Data System (ADS)

Ciofu, C.; Stan, G.

2016-08-01

The paper emphasise positioning precision of an elephant's trunk robotic arm which has joints driven by wires with variable length while operating The considered 5 degrees of freedom robotic arm has a particular structure of joint that makes possible inner actuation with wire-driven mechanism. We analyse solely the length change of wires as a consequence due inner winding and unwinding on joints for certain values of rotational angles. Variations in wires length entail joint angular displacements. We analyse positioning precision by taking into consideration equations from inverse kinematics of the elephant's trunk robotic arm. The angular displacements of joints are considered into computational method after partial derivation of positioning equations. We obtain variations of wires length at about tenths of micrometers. These variations employ angular displacements which are about minutes of sexagesimal degree and, thus, define positioning precision of elephant's trunk robotic arms. The analytical method is used for determining aftermath design structure of an elephant's trunk robotic arm with inner actuation through wires on positioning precision. Thus, designers could take suitable decisions on accuracy specifications limits of the robotic arm.

Natural selection in the colloid world: active chiral spirals.

PubMed

Zhang, Jie; Granick, Steve

2016-10-06

We present a model system in which to study natural selection in the colloid world. In the assembly of active Janus particles into rotating pinwheels when mixed with trace amounts of homogeneous colloids in the presence of an AC electric field, broken symmetry in the rotation direction produces spiral, chiral shapes. Locked into a central rotation point by the centre particle, the spiral arms are found to trail rotation of the overall cluster. To achieve a steady state, the spiral arms undergo an evolutionary process to coordinate their motion. Because all the particles as segments of the pinwheel arms are self-propelled, asymmetric arm lengths are tolerated. Reconfiguration of these structures can happen in various ways and various mechanisms of this directed structural change are analyzed in detail. We introduce the concept of VIP (very important particles) to express that sustainability of active structures is most sensitive to only a few particles at strategic locations in the moving self-assembled structures.

Continuum robot arms inspired by cephalopods

NASA Astrophysics Data System (ADS)

Walker, Ian D.; Dawson, Darren M.; Flash, Tamar; Grasso, Frank W.; Hanlon, Roger T.; Hochner, Binyamin; Kier, William M.; Pagano, Christopher C.; Rahn, Christopher D.; Zhang, Qiming M.

2005-05-01

In this paper, we describe our recent results in the development of a new class of soft, continuous backbone ("continuum") robot manipulators. Our work is strongly motivated by the dexterous appendages found in cephalopods, particularly the arms and suckers of octopus, and the arms and tentacles of squid. Our ongoing investigation of these animals reveals interesting and unexpected functional aspects of their structure and behavior. The arrangement and dynamic operation of muscles and connective tissue observed in the arms of a variety of octopus species motivate the underlying design approach for our soft manipulators. These artificial manipulators feature biomimetic actuators, including artificial muscles based on both electro-active polymers (EAP) and pneumatic (McKibben) muscles. They feature a "clean" continuous backbone design, redundant degrees of freedom, and exhibit significant compliance that provides novel operational capacities during environmental interaction and object manipulation. The unusual compliance and redundant degrees of freedom provide strong potential for application to delicate tasks in cluttered and/or unstructured environments. Our aim is to endow these compliant robotic mechanisms with the diverse and dexterous grasping behavior observed in octopuses. To this end, we are conducting fundamental research into the manipulation tactics, sensory biology, and neural control of octopuses. This work in turn leads to novel approaches to motion planning and operator interfaces for the robots. The paper describes the above efforts, along with the results of our development of a series of continuum tentacle-like robots, demonstrating the unique abilities of biologically-inspired design.

The Chlamydomonas Dhc1 gene encodes a dynein heavy chain subunit required for assembly of the I1 inner arm complex.

PubMed Central

Myster, S H; Knott, J A; O'Toole, E; Porter, M E

1997-01-01

Multiple members of the dynein heavy chain (Dhc) gene family have been recovered in several organisms, but the relationships between these sequences and the Dhc isoforms that they encode are largely unknown. To identify Dhc loci and determine the specific functions of the individual Dhc isoforms, we have screened a collection of motility mutants generated by insertional mutagenesis in Chlamydomonas. In this report, we characterize one strain, pf9-3, in which the insertion event was accompanied by a deletion of approximately 13 kb of genomic DNA within the transcription unit of the Dhc1 gene. Northern blot analysis confirms that pf9-3 is a null mutation. Biochemical and structural studies of isolated axonemes demonstrate that the pf9-3 mutant fails to assemble the I1 inner arm complex, a two-headed dynein isoform composed of two Dhcs (1 alpha and 1 beta) and three intermediate chains. To determine if the Dhc1 gene product corresponds to one of the Dhcs of the I1 complex, antibodies were generated against a Dhc1-specific peptide sequence. Immunoblot analysis reveals that the Dhc1 gene encodes the 1 alpha Dhc subunit. These studies thus, identify the first inner arm Dhc locus to be described in any organism and further demonstrate that the 1 alpha Dhc subunit plays an essential role in the assembly of the I1 inner arm complex. Images PMID:9247642

A potential role for chondroitin sulfate/dermatan sulfate in arm regeneration in Amphiura filiformis.

PubMed

Ramachandra, Rashmi; Namburi, Ramesh B; Dupont, Sam T; Ortega-Martinez, Olga; van Kuppevelt, Toin H; Lindahl, Ulf; Spillmann, Dorothe

2017-05-01

Glycosaminoglycans (GAGs), such as chondroitin sulfate (CS) and dermatan sulfate (DS) from various vertebrate and invertebrate sources are known to be involved in diverse cellular mechanisms during repair and regenerative processes. Recently, we have identified CS/DS as the major GAG in the brittlestar Amphiura filiformis, with high proportions of di- and tri-O-sulfated disaccharide units. As this echinoderm is known for its exceptional regeneration capacity, we aimed to explore the role of these GAG chains during A. filiformis arm regeneration. Analysis of CS/DS chains during the regeneration process revealed an increase in the proportion of the tri-O-sulfated disaccharides. Conversely, treatment of A. filiformis with sodium chlorate, a potent inhibitor of sulfation reactions in GAG biosynthesis, resulted in a significant reduction in arm growth rates with total inhibition at concentrations higher than 5 mM. Differentiation was less impacted by sodium chlorate exposure or even slightly increased at 1-2 mM. Based on the structural changes observed during arm regeneration we identified chondroitin synthase, chondroitin-4-O-sulfotransferase 2 and dermatan-4-O-sulfotransferase as candidate genes and sought to correlate their expression with the expression of the A. filiformis orthologue of bone morphogenetic factors, AfBMP2/4. Quantitative amplification by real-time PCR indicated increased expression of chondroitin synthase and chondroitin-4-O-sulfotransferase 2, with a corresponding increase in AfBMP2/4 during regeneration relative to nonregenerating controls. Our findings suggest that proper sulfation of GAGs is important for A. filiformis arm regeneration and that these molecules may participate in mechanisms controlling cell proliferation. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Coordination of multiple robot arms

NASA Technical Reports Server (NTRS)

Barker, L. K.; Soloway, D.

1987-01-01

Kinematic resolved-rate control from one robot arm is extended to the coordinated control of multiple robot arms in the movement of an object. The structure supports the general movement of one axis system (moving reference frame) with respect to another axis system (control reference frame) by one or more robot arms. The grippers of the robot arms do not have to be parallel or at any pre-disposed positions on the object. For multiarm control, the operator chooses the same moving and control reference frames for each of the robot arms. Consequently, each arm then moves as though it were carrying out the commanded motions by itself.

Design and synthesis of diverse functional kinked nanowire structures for nanoelectronic bioprobes.

PubMed

Xu, Lin; Jiang, Zhe; Qing, Quan; Mai, Liqiang; Zhang, Qingjie; Lieber, Charles M

2013-02-13

Functional kinked nanowires (KNWs) represent a new class of nanowire building blocks, in which functional devices, for example, nanoscale field-effect transistors (nanoFETs), are encoded in geometrically controlled nanowire superstructures during synthesis. The bottom-up control of both structure and function of KNWs enables construction of spatially isolated point-like nanoelectronic probes that are especially useful for monitoring biological systems where finely tuned feature size and structure are highly desired. Here we present three new types of functional KNWs including (1) the zero-degree KNW structures with two parallel heavily doped arms of U-shaped structures with a nanoFET at the tip of the "U", (2) series multiplexed functional KNW integrating multi-nanoFETs along the arm and at the tips of V-shaped structures, and (3) parallel multiplexed KNWs integrating nanoFETs at the two tips of W-shaped structures. First, U-shaped KNWs were synthesized with separations as small as 650 nm between the parallel arms and used to fabricate three-dimensional nanoFET probes at least 3 times smaller than previous V-shaped designs. In addition, multiple nanoFETs were encoded during synthesis in one of the arms/tip of V-shaped and distinct arms/tips of W-shaped KNWs. These new multiplexed KNW structures were structurally verified by optical and electron microscopy of dopant-selective etched samples and electrically characterized using scanning gate microscopy and transport measurements. The facile design and bottom-up synthesis of these diverse functional KNWs provides a growing toolbox of building blocks for fabricating highly compact and multiplexed three-dimensional nanoprobes for applications in life sciences, including intracellular and deep tissue/cell recordings.

Piezoelectric micromotor based on the structure of serial bending arms.

PubMed

Tong, Jianhua; Cui, Tianhong; Shao, Peige; Wang, Liding

2003-09-01

This paper presents a new piezoelectric micromotor based on the structure of serial bending arms. Serial bending arms are composed of two piezoelectric bimorphs with one end fixed and the other end free, driven by two signals of a biased square wave with a phase difference of pi/2. The free end of a cantilever arm will move along an elliptic orbit so that the cantilever is used to drive a cylinder rotor. The rotor's end surface contacts the free end of the cantilever, resulting in the rotor's rotation. There are six serial bending arms anchored on the base. The driving mechanism of the micromotor is proposed and analyzed. A new micromotor prototype, 5 mm in diameter, has been fabricated and characterized. The maximum rotational speed reaches 325 rpm, and the output torque is about 36.5 microNm.

Worldwide Report, Arms Control

DTIC Science & Technology

1986-02-28

NACHRICHTEN , 18 Oct 85) 39 Presummit Polish Reporting on SDI Issues (Warsaw RZECZPOSPOLITA, 19-20 Oct 85; Warsaw ZYCIE WARSZAWY, 15 Oct 85) 42...28 February 1986 SDI AND SPACE ARMS MEETING REVEALS SOME SUPPORT FOR EUREKA LINK TO MILITARY Puesseldbrf VDI NACHRICHTEN in German 18 Oct 85 p 10

The relation between magnetic and material arms in models for spiral galaxies

NASA Astrophysics Data System (ADS)

Moss, D.; Beck, R.; Sokoloff, D.; Stepanov, R.; Krause, M.; Arshakian, T. G.

2013-08-01

Context. Observations of polarized radio emission show that large-scale (regular) magnetic fields in spiral galaxies are not fully axisymmetric, but generally stronger in interarm regions. In some nearby galaxies such as NGC 6946 they are organized in narrow magnetic arms situated between the material spiral arms. Aims: The phenomenon of magnetic arms and their relation to the optical spiral arms (the material arms) calls for an explanation in the framework of galactic dynamo theory. Several possibilities have been suggested but are not completely satisfactory; here we attempt a consistent investigation. Methods: We use a 2D mean-field dynamo model in the no-z approximation and add injections of small-scale magnetic field, taken to result from supernova explosions, to represent the effects of dynamo action on smaller scales. This injection of small scale field is situated along the spiral arms, where star-formation mostly occurs. Results: A straightforward explanation of magnetic arms as a result of modulation of the dynamo mechanism by material arms struggles to produce pronounced magnetic arms, at least with realistic parameters, without introducing new effects such as a time lag between Coriolis force and α-effect. In contrast, by taking into account explicitly the small-scale magnetic field that is injected into the arms by the action of the star forming regions that are concentrated there, we can obtain dynamo models with magnetic structures of various forms that can be compared with magnetic arms. These are rather variable entities and their shape changes significantly on timescales of a few 100 Myr. Properties of magnetic arms can be controlled by changing the model parameters. In particular, a lower injection rate of small-scale field makes the magnetic configuration smoother and eliminates distinct magnetic arms. Conclusions: We conclude that magnetic arms can be considered as coherent magnetic structures generated by large-scale dynamo action, and associated with spatially modulated small-scale magnetic fluctuations, caused by enhanced star formation rates within the material arms.

Crystal structure of the motor domain of a class-I myosin

PubMed Central

Kollmar, Martin; Dürrwang, Ulrike; Kliche, Werner; Manstein, Dietmar J.; Kull, F.Jon

2002-01-01

The crystal structure of the motor domain of Dictyostelium discoideum myosin-IE, a monomeric unconventional myosin, was determined. The crystallographic asymmetric unit contains four independently resolved molecules, highlighting regions that undergo large conformational changes. Differences are particularly pronounced in the actin binding region and the converter domain. The changes in position of the converter domain reflect movements both parallel to and perpendicular to the actin axis. The orientation of the converter domain is ∼30° further up than in other myosin structures, indicating that MyoE can produce a larger power stroke by rotating its lever arm through a larger angle. The role of extended loops near the actin-binding site is discussed in the context of cellular localization. The core regions of the motor domain are similar, and the structure reveals how that core is stabilized in the absence of an N-terminal SH3-like domain. PMID:12032065

Early whole brain radiotherapy in primary CNS lymphoma: negative impact on quality of life in the randomized G-PCNSL-SG1 trial.

PubMed

Herrlinger, Ulrich; Schäfer, Niklas; Fimmers, Rolf; Griesinger, Frank; Rauch, Michael; Kirchen, Heinz; Roth, Patrick; Glas, Martin; Bamberg, Michael; Martus, Peter; Thiel, Eckhard; Korfel, Agnieszka; Weller, Michael

2017-09-01

In the randomized G-PCNSL-SG-1 trial, the addition of whole brain radiotherapy (45 Gy) to high-dose methotrexate (HD-MTX)-based chemotherapy (early WBRT arm) did not prolong overall survival (OS) as compared to HD-MTX-based chemotherapy alone (no early WBRT arm) in primary CNS lymphoma (PCNSL) patients. To determine whether WBRT might lead to quality of life (QoL)-relevant late neurotoxicity, this trial prospectively monitored QoL. QoL measurements were performed using the EORTC-QLQ-C30 and BN20 questionnaires and combined with repeated Mini Mental State Examinations (MMSE). Exploratory data analysis included the 318 patients in the per-protocol population. In year 2 after randomization, cognitive functioning and global health status were reduced in the early WBRT arm as compared to the no early WBRT arm (p = 0.004 and p = 0.022, respectively). Also, fatigue (p = 0.037), appetite loss (p = 0.006) and hair loss (p = 0.002) were more intense in the early WBRT arm. MMSE testing revealed lower values (p = 0.002) in the early WBRT arm. A mixed model analysis of longitudinal data additionally showed differences favoring the no early WBRT arm in 15 of 26 dimensions of QoL. The analysis of subjective QoL questionnaires and objective MMSE testing revealed that QoL and cognition were conserved in the arm without early WBRT. Thus, even though it was an exploratory analysis, the results of G-PCNSL-SG1 challenge the place of WBRT in the primary therapy of PCNSL.

Feeding strategies as revealed by the section moduli of the humerus bones in bipedal theropod dinosaurs

NASA Astrophysics Data System (ADS)

Lee, Scott; Richards, Zachary

2015-03-01

The section modulus of a bone is a measure of its ability to resist bending torques. Carnivorous dinosaurs presumably had strong arm bones to hold struggling prey during hunting. Some theropods are believed to have become herbivorous and such animals would not have needed such strong arms. In this work, the section moduli of the humerus bones of bipedal theropod dinosaurs (from Microvenator celer to Tyrannosaurus rex) are studied to determine the maximum bending loads their arms could withstand. The results show that bending strength is not of uniform importance to these magnificent animals. The predatory theropods had strong arms for use in hunting. In contrast, the herbivorous dinosaurs had weaker arms.

FOREST unbiased Galactic plane imaging survey with the Nobeyama 45 m telescope (FUGIN). I. Project overview and initial results

NASA Astrophysics Data System (ADS)

Umemoto, Tomofumi; Minamidani, Tetsuhiro; Kuno, Nario; Fujita, Shinji; Matsuo, Mitsuhiro; Nishimura, Atsushi; Torii, Kazufumi; Tosaki, Tomoka; Kohno, Mikito; Kuriki, Mika; Tsuda, Yuya; Hirota, Akihiko; Ohashi, Satoshi; Yamagishi, Mitsuyoshi; Handa, Toshihiro; Nakanishi, Hiroyuki; Omodaka, Toshihiro; Koide, Nagito; Matsumoto, Naoko; Onishi, Toshikazu; Tokuda, Kazuki; Seta, Masumichi; Kobayashi, Yukinori; Tachihara, Kengo; Sano, Hidetoshi; Hattori, Yusuke; Onodera, Sachiko; Oasa, Yumiko; Kamegai, Kazuhisa; Tsuboi, Masato; Sofue, Yoshiaki; Higuchi, Aya E.; Chibueze, James O.; Mizuno, Norikazu; Honma, Mareki; Muller, Erik; Inoue, Tsuyoshi; Morokuma-Matsui, Kana; Shinnaga, Hiroko; Ozawa, Takeaki; Takahashi, Ryo; Yoshiike, Satoshi; Costes, Jean; Kuwahara, Sho

2017-10-01

The FUGIN project is one of legacy projects using a new multi-beam FOREST (four-beam receiver system on the 45 m telescope). This project aims to simultaneously investigate the distribution, kinematics, and physical properties of both diffuse and dense molecular gases in the Galaxy by observing 12CO, 13CO, and C18O J = 1-0 lines simultaneously. Mapping regions are parts of the first quadrant (10° ≤ l ≤ 50°, |b| ≤ 1°) and the third quadrant (198° ≤ l ≤ 236°, |b| ≤ 1°) of the Galaxy, where spiral arms, bar structure, and the molecular gas ring are included. This survey achieves the highest angular resolution to date (˜20″) for the Galactic plane survey in the CO J = 1-0 lines, which makes it possible to find dense clumps located farther away than the previous surveys. FUGIN will provide us an invaluable dataset for investigating the physics of the Galactic interstellar medium (ISM), particularly the evolution of interstellar gas covering galactic-scale structures to the internal structures of giant molecular clouds, such as small filaments/clumps/cores. We present an overview of the FUGIN project, the observation plan and initial results. These results reveal wide-field and detailed structures of molecular clouds, such as entangled filaments that have not been obvious in previous surveys, and large-scale kinematics of molecular gas, such as spiral arms.

The Mr 140,000 Intermediate Chain of Chlamydomonas Flagellar Inner Arm Dynein Is a WD-Repeat Protein Implicated in Dynein Arm Anchoring

PubMed Central

Yang, Pinfen; Sale, Winfield S.

1998-01-01

Previous structural and biochemical studies have revealed that the inner arm dynein I1 is targeted and anchored to a unique site located proximal to the first radial spoke in each 96-nm axoneme repeat on flagellar doublet microtubules. To determine whether intermediate chains mediate the positioning and docking of dynein complexes, we cloned and characterized the 140-kDa intermediate chain (IC140) of the I1 complex. Sequence and secondary structural analysis, with particular emphasis on β-sheet organization, predicted that IC140 contains seven WD repeats. Reexamination of other members of the dynein intermediate chain family of WD proteins indicated that these polypeptides also bear seven WD/β-sheet repeats arranged in the same pattern along each intermediate chain protein. A polyclonal antibody was raised against a 53-kDa fusion protein derived from the C-terminal third of IC140. The antibody is highly specific for IC140 and does not bind to other dynein intermediate chains or proteins in Chlamydomonas flagella. Immunofluorescent microscopy of Chlamydomonas cells confirmed that IC140 is distributed along the length of both flagellar axonemes. In vitro reconstitution experiments demonstrated that the 53-kDa C-terminal fusion protein binds specifically to axonemes lacking the I1 complex. Chemical cross-linking indicated that IC140 is closely associated with a second intermediate chain in the I1 complex. These data suggest that IC140 contains domains responsible for the assembly and docking of the I1 complex to the doublet microtubule cargo. PMID:9843573

DOE Office of Scientific and Technical Information (OSTI.GOV)

Solanki, Ashish K.; Rathore, Yogendra S.; Badmalia, Maulik D.

Asymmetric disposition of Fab arms in the structures solved for the broadly neutralizing monoclonal antibody (nmAb) IgG1 b12 raised the question of whether the unusual shape observed for b12 is common for all IgG1 mAbs or if there is a difference in the overall shape of nmAbs versus non-nmAbs. In this paper, we compared small angle x-ray scattering (SAXS) data-based models and limited proteolysis profiles of some IgG1 mAbs known to be having and lacking HIV-1 neutralizing potency. In non-nmAbs, the Fab arms were found to be symmetrically disposed in space relative to central Fc, but in most nmAbs, themore » Fab arms were asymmetrically disposed, as seen for IgG1 b12. The only exceptions were 2G12 and 4E10, where both Fab arms were closed above Fc, suggesting some Fab-Fc and/or Fab-Fab interaction in the nmAbs that constrained extension of the Fab-Fc linker. Interestingly, these observations were correlated with differential proteolysis profiles of the mAbs by papain. Under conditions when papain could cut both Fab arms of non-nmAbs, only one Fab arm could be removed from neutralizing ones (except for 2G12 and 4E10). Chromatography and small angle x-ray scattering results of papain-digested products revealed that 1) the Fab-Fc or Fab-Fab interactions in unliganded mAbs are retained in digested products, and 2) whereas anti-gp120 non-nmAbs could bind two gp120 molecules, nmAbs could bind only one gp120. Finally, additional experiments showed that except for 2G12 and 4E10, unopen shapes of nmAbs remain uninfluenced by ionic strength but can be reversibly opened by low pH of buffer accompanied by loss of ligand binding ability.« less

Global Shape and Ligand Binding Efficiency of the HIV-1-neutralizing Antibodies Differ from Those of Antibodies That Cannot Neutralize HIV-1*

PubMed Central

Solanki, Ashish K.; Rathore, Yogendra S.; Badmalia, Maulik D.; Dhoke, Reema R.; Nath, Samir K.; Nihalani, Deepak; Ashish

2014-01-01

Asymmetric disposition of Fab arms in the structures solved for the broadly neutralizing monoclonal antibody (nmAb) IgG1 b12 raised the question of whether the unusual shape observed for b12 is common for all IgG1 mAbs or if there is a difference in the overall shape of nmAbs versus non-nmAbs. We compared small angle x-ray scattering (SAXS) data-based models and limited proteolysis profiles of some IgG1 mAbs known to be having and lacking HIV-1 neutralizing potency. In non-nmAbs, the Fab arms were found to be symmetrically disposed in space relative to central Fc, but in most nmAbs, the Fab arms were asymmetrically disposed, as seen for IgG1 b12. The only exceptions were 2G12 and 4E10, where both Fab arms were closed above Fc, suggesting some Fab-Fc and/or Fab-Fab interaction in the nmAbs that constrained extension of the Fab-Fc linker. Interestingly, these observations were correlated with differential proteolysis profiles of the mAbs by papain. Under conditions when papain could cut both Fab arms of non-nmAbs, only one Fab arm could be removed from neutralizing ones (except for 2G12 and 4E10). Chromatography and small angle x-ray scattering results of papain-digested products revealed that 1) the Fab-Fc or Fab-Fab interactions in unliganded mAbs are retained in digested products, and 2) whereas anti-gp120 non-nmAbs could bind two gp120 molecules, nmAbs could bind only one gp120. Additional experiments showed that except for 2G12 and 4E10, unopen shapes of nmAbs remain uninfluenced by ionic strength but can be reversibly opened by low pH of buffer accompanied by loss of ligand binding ability. PMID:25331945

Global Shape and Ligand Binding Efficiency of the HIV-1-neutralizing Antibodies Differ from Those of Antibodies That Cannot Neutralize HIV-1

DOE PAGES

Solanki, Ashish K.; Rathore, Yogendra S.; Badmalia, Maulik D.; ...

2014-10-20

Asymmetric disposition of Fab arms in the structures solved for the broadly neutralizing monoclonal antibody (nmAb) IgG1 b12 raised the question of whether the unusual shape observed for b12 is common for all IgG1 mAbs or if there is a difference in the overall shape of nmAbs versus non-nmAbs. In this paper, we compared small angle x-ray scattering (SAXS) data-based models and limited proteolysis profiles of some IgG1 mAbs known to be having and lacking HIV-1 neutralizing potency. In non-nmAbs, the Fab arms were found to be symmetrically disposed in space relative to central Fc, but in most nmAbs, themore » Fab arms were asymmetrically disposed, as seen for IgG1 b12. The only exceptions were 2G12 and 4E10, where both Fab arms were closed above Fc, suggesting some Fab-Fc and/or Fab-Fab interaction in the nmAbs that constrained extension of the Fab-Fc linker. Interestingly, these observations were correlated with differential proteolysis profiles of the mAbs by papain. Under conditions when papain could cut both Fab arms of non-nmAbs, only one Fab arm could be removed from neutralizing ones (except for 2G12 and 4E10). Chromatography and small angle x-ray scattering results of papain-digested products revealed that 1) the Fab-Fc or Fab-Fab interactions in unliganded mAbs are retained in digested products, and 2) whereas anti-gp120 non-nmAbs could bind two gp120 molecules, nmAbs could bind only one gp120. Finally, additional experiments showed that except for 2G12 and 4E10, unopen shapes of nmAbs remain uninfluenced by ionic strength but can be reversibly opened by low pH of buffer accompanied by loss of ligand binding ability.« less

User interface development and metadata considerations for the Atmospheric Radiation Measurement (ARM) archive

NASA Technical Reports Server (NTRS)

Singley, P. T.; Bell, J. D.; Daugherty, P. F.; Hubbs, C. A.; Tuggle, J. G.

1993-01-01

This paper will discuss user interface development and the structure and use of metadata for the Atmospheric Radiation Measurement (ARM) Archive. The ARM Archive, located at Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, is the data repository for the U.S. Department of Energy's (DOE's) ARM Project. After a short description of the ARM Project and the ARM Archive's role, we will consider the philosophy and goals, constraints, and prototype implementation of the user interface for the archive. We will also describe the metadata that are stored at the archive and support the user interface.

Protective effects of Tualang honey on bone structure in experimental postmenopausal rats

PubMed Central

Zaid, Siti Sarah Mohamad; Sulaiman, Siti Amrah; Othman, Nor Hayati; Soelaiman, Ima-Nirwana; Shuid, Ahmad Nazrun; Mohamad, Norazlina; Muhamad, Norliza

2012-01-01

OBJECTIVE: The objective of this study was to evaluate the effects of Tualang honey on trabecular structure and compare these effects with those of calcium supplementation in ovariectomized rats. METHODS: Forty female, Sprague-Dawley rats were randomly divided into five groups (n = 8): four controls and one test arm. The control arm comprised a baseline control, sham-operated control, ovariectomized control, and ovariectomized calcium-treated rats (receiving 1% calcium in drinking water ad libitum). The test arm was composed of ovariectomized, Tualang honey-treated rats (received 0.2 g/kg body weight of Tualang honey). Both the sham-operated control and ovariectomized control groups received vehicle treatment (deionized water), and the baseline control group was sacrificed without treatment. RESULTS: All rats were orally gavaged daily for six weeks after day one post-surgery. The bone structural analysis of rats in the test arm group showed a significant increase in the bone volume per tissue volume (BV/TV), trabecular thickness (Tb.Th) and trabecular number (Tb.N) and a significant decrease in inter-trabecular space (Tb.Sp) compared with the ovariectomized control group. The trabecular thickness (Tb.Th) in the test arm group was significantly higher compared with the ovariectomized-calcium treated group, and the inter-trabecular space (Tb.Sp) in the test arm group was significantly narrower compared with the ovariectomized-calcium treated group. CONCLUSION: In conclusion, ovariectomized rats that received Tualang honey showed more improvements in trabecular bone structure than the rats that received calcium. PMID:22892923

Protective effects of Tualang honey on bone structure in experimental postmenopausal rats.

PubMed

Zaid, Siti Sarah Mohamad; Sulaiman, Siti Amrah; Othman, Nor Hayati; Soelaiman, Ima-Nirwana; Shuid, Ahmad Nazrun; Mohamad, Norazlina; Muhamad, Norliza

2012-07-01

The objective of this study was to evaluate the effects of Tualang honey on trabecular structure and compare these effects with those of calcium supplementation in ovariectomized rats. Forty female, Sprague-Dawley rats were randomly divided into five groups (n =8): four controls and one test arm. The control arm comprised a baseline control, sham-operated control, ovariectomized control, and ovariectomized calcium-treated rats (receiving 1% calcium in drinking water ad libitum). The test arm was composed of ovariectomized, Tualang honey-treated rats (received 0.2 g/kg body weight of Tualang honey). Both the sham-operated control and ovariectomized control groups received vehicle treatment (deionized water), and the baseline control group was sacrificed without treatment. All rats were orally gavaged daily for six weeks after day one post-surgery. The bone structural analysis of rats in the test arm group showed a significant increase in the bone volume per tissue volume (BV/TV), trabecular thickness (Tb.Th) and trabecular number (Tb.N) and a significant decrease in inter-trabecular space (Tb.Sp) compared with the ovariectomized control group. The trabecular thickness (Tb.Th) in the test arm group was significantly higher compared with the ovariectomized-calcium treated group, and the inter-trabecular space (Tb.Sp) in the test arm group was significantly narrower compared with the ovariectomized-calcium treated group. In conclusion, ovariectomized rats that received Tualang honey showed more improvements in trabecular bone structure than the rats that received calcium.

Karyotype differentiation of four Cestrum species (Solanaceae) revealed by fluorescent chromosome banding and FISH

PubMed Central

2009-01-01

The karyotypes of four South American species of Cestrum (C. capsulare,C. corymbosum,C. laevigatum and C. megalophylum) were studied using conventional staining, C-CMA/DAPI chromosome banding and FISH with 45S and 5S rDNA probes. The karyotypes showed a chromosome number of 2n = 2x = 16, with metacentric chromosomes, except for the eighth submeta- to acrocentric pair. Several types of heterochromatin were detected, which varied in size, number, distribution and base composition. The C-CMA+ bands and 45S rDNA were located predominantly in terminal regions. The C-CMA + /DAPI + bands appeared in interstitial and terminal regions, and the C-DAPI + bands were found in all chromosome regions. The 5S rDNA sites were observed on the long arm of pair 8 in all species except C. capsulare, where they were found in the paracentromeric region of the long arm of pair 4. The differences in band patterns among the species studied here, along with data from other nine species reported in the literature, suggest that the bands are dispersed in an equilocal and non-equilocal manner and that structural rearrangements can be responsible for internal karyotype diversification. However, it is important to point out that the structural changes involving repetitive segments did not culminate in substantial changes in the general karyotype structure concerning chromosome size and morphology. PMID:21637687

The Impact of Financial Sophistication on Adjustable Rate Mortgage Ownership

ERIC Educational Resources Information Center

Smith, Hyrum; Finke, Michael S.; Huston, Sandra J.

2011-01-01

The influence of a financial sophistication scale on adjustable-rate mortgage (ARM) borrowing is explored. Descriptive statistics and regression analysis using recent data from the Survey of Consumer Finances reveal that ARM borrowing is driven by both the least and most financially sophisticated households but for different reasons. Less…

Microporous structure with layered interstitial surface treatment, and method and apparatus for preparation thereof

NASA Technical Reports Server (NTRS)

Koontz, Steven L. (Inventor)

1994-01-01

A microporous structure with layered interstitial surface treatments, and method and apparatus for preparation thereof is presented. The structure is prepared by sequentially subjecting a uniformly surface-treated structure to atomic oxygen treatment to remove an outer layer of surface treatment to a generally uniform depth, and then surface treating the so exposed layer with another surface treating agent. The atomic oxygen/surface treatment steps may optionally be repeated, each successive time to a lesser depth, to produce a microporous structure having multilayered surface treatments. The apparatus employs at least one side arm from a main atomic oxygen-containing chamber. The side arm has characteristic relaxation times such that a uniform atomic oxygen dose rate is delivered to a specimen positioned transversely in the side arm spaced from the main gas chamber.

Microporous structure with layered interstitial surface treatment, and method and apparatus for preparation thereof

NASA Technical Reports Server (NTRS)

Koontz, Steven L. (Inventor)

1992-01-01

A microporous structure with layered interstitial surface treatments, and the method and apparatus for its preparation are disclosed. The structure is prepared by sequentially subjecting a uniformly surface treated structure to atomic oxygen treatment to remove an outer layer of surface treatment to a generally uniform depth, and then surface treating the so exposed layer with another surface treating agent. The atomic oxygen/surface treatment steps may optionally be repeated, each successive time to a lesser depth, to produce a microporous structure having multilayered surface treatments. The apparatus employs at least one side arm from a main oxygen-containing chamber. The side arm has characteristic relaxation times such that a uniform atomic oxygen dose rate is delivered to a specimen positioned transversely in the side arm spaced from the main gas chamber.

Star-Shaped Conjugated Molecules with Oxa- or Thiadiazole Bithiophene Side Arms.

PubMed

Kotwica, Kamil; Kostyuchenko, Anastasia S; Data, Przemyslaw; Marszalek, Tomasz; Skorka, Lukasz; Jaroch, Tomasz; Kacka, Sylwia; Zagorska, Malgorzata; Nowakowski, Robert; Monkman, Andrew P; Fisyuk, Alexander S; Pisula, Wojciech; Pron, Adam

2016-08-08

Star-shaped conjugated molecules, consisting of a benzene central unit symmetrically trisubstituted with either oxa- or thiadiazole bithiophene groups, were synthesized as promising molecules and building blocks for application in (opto)electronics and electrochromic devices. Their optical (Eg (opt)) as well as electrochemical (Eg (electro)) band gaps depended on the type of the side arm and the number of solubilizing alkyl substituents. Oxadiazole derivatives showed Eg (opt) slightly below 3 eV and by 0.2 eV larger than those determined for thiadiazole-based compounds. The presence of alkyl substituents in the arms additionally lowered the band gap. The obtained compounds were efficient electroluminophores in guest/host-type light-emitting diodes. They also showed a strong tendency to self-organize in monolayers deposited on graphite, as evidenced by scanning tunneling microscopy. The structural studies by X-ray scattering revealed the formation of supramolecular columnar stacks in which the molecules were organized. Differences in macroscopic alignment in the specimen indicated variations in the self-assembly mechanism between the molecules. The compounds as trifunctional monomers were electrochemically polymerized to yield the corresponding polymer network. As shown by UV/Vis-NIR spectroelectrochemical studies, these networks exhibited reversible electrochromic behavior both in the oxidation and in the reduction modes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Association of Lis1 with outer arm dynein is modulated in response to alterations in flagellar motility

PubMed Central

Rompolas, Panteleimon; Patel-King, Ramila S.; King, Stephen M.

2012-01-01

The cytoplasmic dynein regulatory factor Lis1, which induces a persistent tight binding to microtubules and allows for transport of cargoes under high-load conditions, is also present in motile cilia/flagella. We observed that Lis1 levels in flagella of Chlamydomonas strains that exhibit defective motility due to mutation of various axonemal substructures were greatly enhanced compared with wild type; this increase was absolutely dependent on the presence within the flagellum of the outer arm dynein α heavy chain/light chain 5 thioredoxin unit. To assess whether cells might interpret defective motility as a “high-load environment,” we reduced the flagellar beat frequency of wild-type cells through enhanced viscous load and by reductive stress; both treatments resulted in increased levels of flagellar Lis1, which altered the intrinsic beat frequency of the trans flagellum. Differential extraction of Lis1 from wild-type and mutant axonemes suggests that the affinity of outer arm dynein for Lis1 is directly modulated. In cytoplasm, Lis1 localized to two punctate structures, one of which was located near the base of the flagella. These data reveal that the cell actively monitors motility and dynamically modulates flagellar levels of the dynein regulatory factor Lis1 in response to imposed alterations in beat parameters. PMID:22855525

Exciton Transport Simulations in Phenyl Cored Thiophene Dendrimers

NASA Astrophysics Data System (ADS)

Kim, Kwiseon; Erkan Kose, Muhammet; Graf, Peter; Kopidakis, Nikos; Rumbles, Garry; Shaheen, Sean E.

2009-03-01

Phenyl cored 3-arm and 4-arm thiophene dendrimers are promising materials for use in photovoltaic devices. It is important to understand the energy transfer mechanisms in these molecules to guide the synthesis of novel dendrimers with improved efficiency. A method is developed to estimate the exciton diffusion lengths for the dendrimers and similar chromophores in amorphous films. The approach exploits Fermi's Golden Rule to estimate the energy transfer rates for an ensemble of bimolecular complexes in random orientations. Using Poisson's equation to evaluate Coulomb integrals led to efficient calculation of excitonic couplings between the transition densities. Monte-Carlo simulations revealed the dynamics of energy transport in the dendrimers. Experimental exciton diffusion lengths of the dendrimers range 10 ˜ 20 nm, increasing with the size of the dendrimer. Simulated diffusion lengths correlate well with experiments. The chemical structure of the chromophore, the shape of the transition densities and the exciton lifetime are found to be the most important factors that determine the exciton diffusion length in amorphous films.

KSC-2009-5917

NASA Image and Video Library

2009-10-27

CAPE CANAVERAL, Fla. – Daybreak at Launch Pad 39B at NASA's Kennedy Space Center in Florida reveals the rotating service structure rolled back from around the Constellation Program's 327-foot-tall Ares I-X rocket for launch. The transfer of the pad from the Space Shuttle Program to the Constellation Program took place May 31. Modifications made to the pad include the removal of shuttle unique subsystems, such as the orbiter access arm and a section of the gaseous oxygen vent arm, and the installation of three 600-foot lightning towers, access platforms, environmental control systems and a vehicle stabilization system. The data returned from more than 700 sensors throughout the rocket will be used to refine the design of future launch vehicles and bring NASA one step closer to reaching its exploration goals. The Ares I-X flight test is targeted for Oct. 27. For information on the Ares I-X vehicle and flight test, visit http://www.nasa.gov/aresIX. Photo credit: NASA/Kim Shiflett

Structural basis for complement evasion by Lyme disease pathogen Borrelia burgdorferi.

PubMed

Bhattacharjee, Arnab; Oeemig, Jesper S; Kolodziejczyk, Robert; Meri, Taru; Kajander, Tommi; Lehtinen, Markus J; Iwaï, Hideo; Jokiranta, T Sakari; Goldman, Adrian

2013-06-28

Borrelia burgdorferi spirochetes that cause Lyme borreliosis survive for a long time in human serum because they successfully evade the complement system, an important arm of innate immunity. The outer surface protein E (OspE) of B. burgdorferi is needed for this because it recruits complement regulator factor H (FH) onto the bacterial surface to evade complement-mediated cell lysis. To understand this process at the molecular level, we used a structural approach. First, we solved the solution structure of OspE by NMR, revealing a fold that has not been seen before in proteins involved in complement regulation. Next, we solved the x-ray structure of the complex between OspE and the FH C-terminal domains 19 and 20 (FH19-20) at 2.83 Å resolution. The structure shows that OspE binds FH19-20 in a way similar to, but not identical with, that used by endothelial cells to bind FH via glycosaminoglycans. The observed interaction of OspE with FH19-20 allows the full function of FH in down-regulation of complement activation on the bacteria. This reveals the molecular basis for how B. burgdorferi evades innate immunity and suggests how OspE could be used as a potential vaccine antigen.

Impedance hand controllers for increasing efficiency in teleoperations

NASA Technical Reports Server (NTRS)

Carignan, C.; Tarrant, J.

1989-01-01

An impedance hand controller with direct force feedback is examined as an alternative to bilateral force reflection in teleoperations involving force contact. Experimentation revealed an operator preference for direct force feedback which provided a better feel of contact with the environment. The advantages of variable arm impedance were also made clear in tracking tests where subjects preferred the larger hand controller inertias made possible by the acceleration feedback loop in the master arm. The ability to decouple the hand controller impedance from the slave arm dynamics is expected to be even more significant when the inertial properties of various payloads in the slave arm are considered.

An Analysis of Second-Tier Arms Producing Countries’ Offset Policies: Technology Transfer and Defense Industrial Base Establishment

DTIC Science & Technology

2008-03-01

38  39  ......................... 40  ......................... 42  42  Offsets in the Global Arms Market ...The Global Arms Market Structure .................................................. Increasing Globalization of Defense Industry...109  Overcapacity of the Defense Industry in a Declining Market ........................... 109 Economies of Scale

Rotational foot placement specifies the lever arm of the ground reaction force during the push-off phase of walking initiation.

PubMed

Erdemir, Ahmet; Piazza, Stephen J

2002-06-01

The lever arm of the ground reaction force (GRF) about the talocrural joint axis is a functionally important indicator of the nature of foot loading. Walking initiation experiments (ten subjects; age, 23-29 years) were completed to demonstrate that rotational foot placement is a possible strategy to specify the lever arm. Externally-rotated foot placement resulted in larger lever arms during push-off. A computer simulation of push-off revealed that a decreased lever arm reduces the plantarflexion moment necessary to maintain a constant forward velocity, while increasing the required plantarflexion velocity. Shortening of the foot thus diminishes the muscular force demand but also requires high muscle fiber shortening velocities that may limit the force generating capacity of plantar flexors. Decreased plantar flexion moment and slow walking previously noted in partial-foot amputees may result from shortened lever arms in this manner.

Prosthesis Prescription Protocol of the Arm (PPP-Arm): The implementation of a national prosthesis prescription protocol.

PubMed

Wijdenes, Paula; Brouwers, Michael; van der Sluis, Corry K

2018-02-01

In order to create more uniformity in the prescription of upper limb prostheses by Dutch rehabilitation teams, the development and implementation of a Prosthesis Prescription Protocol of the upper limb (PPP-Arm) was initiated. The aim was to create a national digital protocol to structure, underpin, and evaluate the prescription of upper limb prostheses for clients with acquired or congenital arm defects. Prosthesis Prescription Protocol of the Arm (PPP-Arm) was developed on the basis of the International Classification of Functioning and consisted of several layers. All stakeholders (rehabilitation teams, orthopedic workshops, patients, and insurance companies) were involved in development and implementation. A national project coordinator and knowledge brokers in each team were essential for the project. PPP-Arm was successfully developed and implemented in nine Dutch rehabilitation teams. The protocol improved team collaboration, structure, and completeness of prosthesis prescriptions and treatment uniformity and might be interesting for other countries as well. Clinical relevance A national protocol to prescribe upper limb prostheses can be helpful to create uniformity in treatment of patients with upper limb defects. Such a protocol improves quality of care for all patients in the country.

A Large Complement of the Predicted Arabidopsis ARM Repeat Proteins Are Members of the U-Box E3 Ubiquitin Ligase Family1[w

PubMed Central

Mudgil, Yashwanti; Shiu, Shin-Han; Stone, Sophia L.; Salt, Jennifer N.; Goring, Daphne R.

2004-01-01

The Arabidopsis genome was searched to identify predicted proteins containing armadillo (ARM) repeats, a motif known to mediate protein-protein interactions in a number of different animal proteins. Using domain database predictions and models generated in this study, 108 Arabidopsis proteins were identified that contained a minimum of two ARM repeats with the majority of proteins containing four to eight ARM repeats. Clustering analysis showed that the 108 predicted Arabidopsis ARM repeat proteins could be divided into multiple groups with wide differences in their domain compositions and organizations. Interestingly, 41 of the 108 Arabidopsis ARM repeat proteins contained a U-box, a motif present in a family of E3 ligases, and these proteins represented the largest class of Arabidopsis ARM repeat proteins. In 14 of these U-box/ARM repeat proteins, there was also a novel conserved domain identified in the N-terminal region. Based on the phylogenetic tree, representative U-box/ARM repeat proteins were selected for further study. RNA-blot analyses revealed that these U-box/ARM proteins are expressed in a variety of tissues in Arabidopsis. In addition, the selected U-box/ARM proteins were found to be functional E3 ubiquitin ligases. Thus, these U-box/ARM proteins represent a new family of E3 ligases in Arabidopsis. PMID:14657406

A large complement of the predicted Arabidopsis ARM repeat proteins are members of the U-box E3 ubiquitin ligase family.

PubMed

Mudgil, Yashwanti; Shiu, Shin-Han; Stone, Sophia L; Salt, Jennifer N; Goring, Daphne R

2004-01-01

The Arabidopsis genome was searched to identify predicted proteins containing armadillo (ARM) repeats, a motif known to mediate protein-protein interactions in a number of different animal proteins. Using domain database predictions and models generated in this study, 108 Arabidopsis proteins were identified that contained a minimum of two ARM repeats with the majority of proteins containing four to eight ARM repeats. Clustering analysis showed that the 108 predicted Arabidopsis ARM repeat proteins could be divided into multiple groups with wide differences in their domain compositions and organizations. Interestingly, 41 of the 108 Arabidopsis ARM repeat proteins contained a U-box, a motif present in a family of E3 ligases, and these proteins represented the largest class of Arabidopsis ARM repeat proteins. In 14 of these U-box/ARM repeat proteins, there was also a novel conserved domain identified in the N-terminal region. Based on the phylogenetic tree, representative U-box/ARM repeat proteins were selected for further study. RNA-blot analyses revealed that these U-box/ARM proteins are expressed in a variety of tissues in Arabidopsis. In addition, the selected U-box/ARM proteins were found to be functional E3 ubiquitin ligases. Thus, these U-box/ARM proteins represent a new family of E3 ligases in Arabidopsis.

LRRC6 Mutation Causes Primary Ciliary Dyskinesia with Dynein Arm Defects

PubMed Central

Horani, Amjad; Ferkol, Thomas W.; Shoseyov, David; Wasserman, Mollie G.; Oren, Yifat S.; Kerem, Batsheva; Amirav, Israel; Cohen-Cymberknoh, Malena; Dutcher, Susan K.; Brody, Steven L.; Elpeleg, Orly; Kerem, Eitan

2013-01-01

Despite recent progress in defining the ciliome, the genetic basis for many cases of primary ciliary dyskinesia (PCD) remains elusive. We evaluated five children from two unrelated, consanguineous Palestinian families who had PCD with typical clinical features, reduced nasal nitric oxide concentrations, and absent dynein arms. Linkage analyses revealed a single common homozygous region on chromosome 8 and one candidate was conserved in organisms with motile cilia. Sequencing revealed a single novel mutation in LRRC6 (Leucine-rich repeat containing protein 6) that fit the model of autosomal recessive genetic transmission, leading to a change of a highly conserved amino acid from aspartic acid to histidine (Asp146His). LRRC6 was localized to the cytoplasm and was up-regulated during ciliogenesis in human airway epithelial cells in a Foxj1-dependent fashion. Nasal epithelial cells isolated from affected individuals and shRNA-mediated silencing in human airway epithelial cells, showed reduced LRRC6 expression, absent dynein arms, and slowed cilia beat frequency. Dynein arm proteins were either absent or mislocalized to the cytoplasm in airway epithelial cells from a primary ciliary dyskinesia subject. These findings suggest that LRRC6 plays a role in dynein arm assembly or trafficking and when mutated leads to primary ciliary dyskinesia with laterality defects. PMID:23527195

SpArcFiRe: Scalable automated detection of spiral galaxy arm segments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, Darren R.; Hayes, Wayne B., E-mail: drdavis@uci.edu, E-mail: whayes@uci.edu

Given an approximately centered image of a spiral galaxy, we describe an entirely automated method that finds, centers, and sizes the galaxy (possibly masking nearby stars and other objects if necessary in order to isolate the galaxy itself) and then automatically extracts structural information about the spiral arms. For each arm segment found, we list the pixels in that segment, allowing image analysis on a per-arm-segment basis. We also perform a least-squares fit of a logarithmic spiral arc to the pixels in that segment, giving per-arc parameters, such as the pitch angle, arm segment length, location, etc. The algorithm takesmore » about one minute per galaxies, and can easily be scaled using parallelism. We have run it on all ∼644,000 Sloan objects that are larger than 40 pixels across and classified as 'galaxies'. We find a very good correlation between our quantitative description of a spiral structure and the qualitative description provided by Galaxy Zoo humans. Our objective, quantitative measures of structure demonstrate the difficulty in defining exactly what constitutes a spiral 'arm', leading us to prefer the term 'arm segment'. We find that pitch angle often varies significantly segment-to-segment in a single spiral galaxy, making it difficult to define the pitch angle for a single galaxy. We demonstrate how our new database of arm segments can be queried to find galaxies satisfying specific quantitative visual criteria. For example, even though our code does not explicitly find rings, a good surrogate is to look for galaxies having one long, low-pitch-angle arm—which is how our code views ring galaxies. SpArcFiRe is available at http://sparcfire.ics.uci.edu.« less

The ringlike structure of macular pigment in age-related maculopathy: results from the Muenster Aging and Retina Study (MARS).

PubMed

Dietzel, Martha; Zeimer, Meike; Heimes, Britta; Pauleikhoff, Daniel; Hense, Hans-Werner

2011-10-11

The role of macular pigment (MP) in age-related maculopathy (ARM) is still not clearly understood. Recent studies have reported on variations in the spatial distribution of MP optical density (MPOD) including a secondary peak ("ring") in the slope of the MPOD profile. The authors investigated in a cross-sectional manner the presence of ringlike structures, their determinants, and their relationship with ARM. In all, 369 participants of the Muenster Aging and Retina Study were examined using dual-wavelength analysis of autofluorescence images. ARM was graded using digital fundus photographs according to the International Classification System. A ringlike structure was observed in 73 (19.8%) study participants. The MP maximum of the ring was located on average at 0.85° and the minimum at 0.48° from the center of the fovea. Their concordance between pairs of eyes was highly significant. MPOD measured at eccentricities of 0°, 0.25°, and 0.5° from the fovea was significantly lower in eyes with ringlike structure, whereas it was significantly higher at 1.0° and 2.0° than that in eyes without the ring. Ringlike structures were significantly more common in females and never smokers and were found significantly less often in eyes with ARM than in healthy eyes, even after adjustment for influential factors (adjusted odds ratio, 0.347; 95% confidence interval, 0.196-0.617). Ringlike structures in the MP spatial profile are fairly common, show a high degree of bilaterality, and appeared inversely related with ARM.

Brain activation underlying threat detection to targets of different races.

PubMed

Senholzi, Keith B; Depue, Brendan E; Correll, Joshua; Banich, Marie T; Ito, Tiffany A

2015-01-01

The current study examined blood oxygen level-dependent signal underlying racial differences in threat detection. During functional magnetic resonance imaging, participants determined whether pictures of Black or White individuals held weapons. They were instructed to make shoot responses when the picture showed armed individuals but don't shoot responses to unarmed individuals, with the cost of not shooting armed individuals being greater than that of shooting unarmed individuals. Participants were faster to shoot armed Blacks than Whites, but faster in making don't shoot responses to unarmed Whites than Blacks. Brain activity differed to armed versus unarmed targets depending on target race, suggesting different mechanisms underlying threat versus safety decisions. Anterior cingulate cortex was preferentially engaged for unarmed Whites than Blacks. Parietal and visual cortical regions exhibited greater activity for armed Blacks than Whites. Seed-based functional connectivity of the amygdala revealed greater coherence with parietal and visual cortices for armed Blacks than Whites. Furthermore, greater implicit Black-danger associations were associated with increased amygdala activation to armed Blacks, compared to armed Whites. Our results suggest that different neural mechanisms may underlie racial differences in responses to armed versus unarmed targets.

Movement Structure in Young and Elderly Adults during Goal-Directed Movements of the Left and Right Arm

ERIC Educational Resources Information Center

Poston, Brach; Van Gemmert, Arend W. A.; Barduson, Beth; Stelmach, George E.

2009-01-01

Elderly adults often exhibit performance deficits during goal-directed movements of the dominant arm compared with young adults. Recent studies involving hemispheric lateralization have provided evidence that the dominant and non-dominant hemisphere-arm systems are specialized for controlling different movement parameters and that hemispheric…

Multi-Scale Modeling of an Integrated 3D Braided Composite with Applications to Helicopter Arm

NASA Astrophysics Data System (ADS)

Zhang, Diantang; Chen, Li; Sun, Ying; Zhang, Yifan; Qian, Kun

2017-10-01

A study is conducted with the aim of developing multi-scale analytical method for designing the composite helicopter arm with three-dimensional (3D) five-directional braided structure. Based on the analysis of 3D braided microstructure, the multi-scale finite element modeling is developed. Finite element analysis on the load capacity of 3D five-directional braided composites helicopter arm is carried out using the software ABAQUS/Standard. The influences of the braiding angle and loading condition on the stress and strain distribution of the helicopter arm are simulated. The results show that the proposed multi-scale method is capable of accurately predicting the mechanical properties of 3D braided composites, validated by the comparison the stress-strain curves of meso-scale RVCs. Furthermore, it is found that the braiding angle is an important factor affecting the mechanical properties of 3D five-directional braided composite helicopter arm. Based on the optimized structure parameters, the nearly net-shaped composite helicopter arm is fabricated using a novel resin transfer mould (RTM) process.

NOTE: On the need to revise the arm structure in stylized anthropomorphic phantoms in lateral photon irradiation geometry

NASA Astrophysics Data System (ADS)

Lee, Choonsik; Lee, Choonik; Lee, Jai-Ki

2006-11-01

Distributions of radiation absorbed dose within human anatomy have been estimated through Monte Carlo radiation transport techniques implemented for two different classes of computational anthropomorphic phantoms: (1) mathematical equation-based stylized phantoms and (2) tomographic image-based voxel phantoms. Voxel phantoms constructed from tomographic images of real human anatomy have been actively developed since the late 1980s to overcome the anatomical approximations necessary with stylized phantoms, which themselves have been utilized since the mid 1960s. However, revisions of stylized phantoms have also been pursued in parallel to the development of voxel phantoms since voxel phantoms (1) are initially restricted to the individual-specific anatomy of the person originally imaged, (2) must be restructured on an organ-by-organ basis to conform to reference individual anatomy and (3) cannot easily represent very fine anatomical structures and tissue layers that are thinner than the voxel dimensions of the overall phantom. Although efforts have been made to improve the anatomic realism of stylized phantoms, most of these efforts have been limited to attempts to alter internal organ structures. Aside from the internal organs, the exterior shapes, and especially the arm structures, of stylized phantoms are also far from realistic descriptions of human anatomy, and may cause dosimetry errors in the calculation of organ-absorbed doses for external irradiation scenarios. The present study was intended to highlight the need to revise the existing arm structure within stylized phantoms by comparing organ doses of stylized adult phantoms with those from three adult voxel phantoms in the lateral photon irradiation geometry. The representative stylized phantom, the adult phantom of the Oak Ridge National Laboratory (ORNL) series and two adult male voxel phantoms, KTMAN-2 and VOXTISS8, were employed for Monte Carlo dose calculation, and data from another voxel phantom, VIP-Man, were obtained from literature sources. The absorbed doses for lungs, oesophagus, liver and kidneys that could be affected by arm structures in the lateral irradiation geometry were obtained for both classes of phantoms in lateral monoenergetic photon irradiation geometries. As expected, those organs in the ORNL phantoms received apparently higher absorbed doses than those in the voxel phantoms. The overestimation is mainly attributed to the relatively poor representation of the arm structure in the ORNL phantom in which the arm bones are embedded within the regions describing the phantom's torso. The results of this study suggest that the overestimation of organ doses, due to unrealistic arm representation, should be taken into account when stylized phantoms are employed for equivalent or effective dose estimates, especially in the case of an irradiation scenario with dominating lateral exposure. For such a reason, the stylized phantom arm structure definition should be revised in order to obtain more realistic evaluations.

Joint cross-correlation analysis reveals complex, time-dependent functional relationship between cortical neurons and arm electromyograms

PubMed Central

Zhuang, Katie Z.; Lebedev, Mikhail A.

2014-01-01

Correlation between cortical activity and electromyographic (EMG) activity of limb muscles has long been a subject of neurophysiological studies, especially in terms of corticospinal connectivity. Interest in this issue has recently increased due to the development of brain-machine interfaces with output signals that mimic muscle force. For this study, three monkeys were implanted with multielectrode arrays in multiple cortical areas. One monkey performed self-timed touch pad presses, whereas the other two executed arm reaching movements. We analyzed the dynamic relationship between cortical neuronal activity and arm EMGs using a joint cross-correlation (JCC) analysis that evaluated trial-by-trial correlation as a function of time intervals within a trial. JCCs revealed transient correlations between the EMGs of multiple muscles and neural activity in motor, premotor and somatosensory cortical areas. Matching results were obtained using spike-triggered averages corrected by subtracting trial-shuffled data. Compared with spike-triggered averages, JCCs more readily revealed dynamic changes in cortico-EMG correlations. JCCs showed that correlation peaks often sharpened around movement times and broadened during delay intervals. Furthermore, JCC patterns were directionally selective for the arm-reaching task. We propose that such highly dynamic, task-dependent and distributed relationships between cortical activity and EMGs should be taken into consideration for future brain-machine interfaces that generate EMG-like signals. PMID:25210153

A multipurpose modular drone with adjustable arms produced via the FDM additive manufacturing process

NASA Astrophysics Data System (ADS)

Brischetto, Salvatore; Ciano, Alessandro; Ferro, Carlo Giovanni

2016-07-01

The present paper shows an innovative multirotor Unmanned Aerial Vehicle (UAV) which is able to easily and quickly change its configuration. In order to satisfy this feature, the principal structure is made of an universal plate, combined with a circular ring, to create a rail guide able to host the arms, in a variable number from 3 to 8, and the legs. The arms are adjustable and contain all the avionic and motor drivers to connect the main structure with each electric motor. The unique arm design, defined as all-in-one, allows classical single rotor configurations, double rotor configurations and amphibious configurations including inflatable elements positioned at the bottom of the arms. The proposed multi-rotor system is inexpensive because of the few universal pieces needed to compose the platform which allows the creation of a kit. This modular kit allows to have a modular drone with different configurations. Such configurations are distinguished among them for the number of arms, number of legs, number of rotors and motors, and landing capability. Another innovation feature is the introduction of the 3D printing technology to produce all the structural elements. In this manner, all the pieces are designed to be produced via the Fused Deposition Modelling (FDM) technology using desktop 3D printers. Therefore, an universal, dynamic and economic multi-rotor UAV has been developed.

Rotating mobile launcher

NASA Technical Reports Server (NTRS)

Gregory, T. J.

1977-01-01

Apparatus holds remotely piloted arm that accelerates until launching speed is reached. Then vehicle and counterweight at other end of arm are released simultaneously to avoid structural damage from unbalanced rotating forces.

Implications of hydrogen/halogen-bond in the stabilization of confined water and anion-water clusters by a cationic receptor

NASA Astrophysics Data System (ADS)

Hoque, Md. Najbul; Das, Gopal

2016-03-01

Anion complexation of benzene capped flexible tripodal receptor and solid state stabilization of discrete hybrid anion-water or infinite water clusters by various supramolecular interactions are reported here. The crystal structure of the receptor in protonated states shows all the three arms projected in one direction. We structurally demonstrate discrete fluoride-water cluster [F2-H2O]2- and square shaped chloride-water cluster [Cl2-(H2O)2]2- inside the cationic channel of the receptor. Structural analysis also reveals that these clusters are stabilized inside the channel through active participation of N/C/Ow‧H⋯Ow, N/C/Ow‧H⋯X- (X- = F-, Cl- and I-) H-bonds and electrostatic interactions. Moreover, C-H⋯π and π⋯π types weak intermolecular interactions appear to play crucial role in supramolecular assembly of receptor. Additionally, on treatment with hydroiodic acid (HI) L resulted zwitterionic iodide complex. Crystal structure reveals the presence of S···I halogen bonded dimer, I2···I halogen bond, 1D infinite water chain and neutral iodine molecules. It is comprehensible that ligand basal structure (benzene capped and N-bridge head in two tripodal) play crucial roles in the formation of diverse halide-water cluster. All structures were well examined by different techniques such as NMR, IR, TGA, DSC, PXRD and XRD.

The magnetic field in the central parsec of the Galaxy

NASA Astrophysics Data System (ADS)

Roche, P. F.; Lopez-Rodriguez, E.; Telesco, C. M.; Schödel, R.; Packham, C.

2018-05-01

We present a polarization map of the warm dust emission from the minispiral in the central parsec of the Galactic Centre. The observations were made at a wavelength of 12.5 μm with CanariCam mounted on the 10.4-m Gran Telescopio Canarias. The magnetic field traced by the polarized emission from aligned dust grains is consistent with previous observations, but the increased resolution of the present data reveals considerably more information on the detailed structure of the B field and its correspondence with the filamentary emission seen in both mid-infrared continuum emission and free-free emission at cm wavelengths. The magnetic field appears to be compressed and pushed by the outflows from luminous stars in the Northern Arm, but it is not disordered by them. We identify some magnetically coherent filaments that cross the Northern Arm at a position angle of ˜45°, and which may trace orbits inclined to the primary orientation of the Northern Arm and circumnuclear disc. In the east-west bar, the magnetic fields implied by the polarization in the lower intensity regions lie predominantly along the bar at a position angle of 130°-140°. In contrast to the Northern Arm, the brighter regions of the bar tend to have lower degrees of polarization with a greater divergence in position angle compared to the local diffuse emission. It appears that the diffuse emission in the east-west bar traces the underlying field and that the bright compact sources are unrelated objects presumably projected on to the bar and with different field orientations.

A reliability study on brain activation during active and passive arm movements supported by an MRI-compatible robot.

PubMed

Estévez, Natalia; Yu, Ningbo; Brügger, Mike; Villiger, Michael; Hepp-Reymond, Marie-Claude; Riener, Robert; Kollias, Spyros

2014-11-01

In neurorehabilitation, longitudinal assessment of arm movement related brain function in patients with motor disability is challenging due to variability in task performance. MRI-compatible robots monitor and control task performance, yielding more reliable evaluation of brain function over time. The main goals of the present study were first to define the brain network activated while performing active and passive elbow movements with an MRI-compatible arm robot (MaRIA) in healthy subjects, and second to test the reproducibility of this activation over time. For the fMRI analysis two models were compared. In model 1 movement onset and duration were included, whereas in model 2 force and range of motion were added to the analysis. Reliability of brain activation was tested with several statistical approaches applied on individual and group activation maps and on summary statistics. The activated network included mainly the primary motor cortex, primary and secondary somatosensory cortex, superior and inferior parietal cortex, medial and lateral premotor regions, and subcortical structures. Reliability analyses revealed robust activation for active movements with both fMRI models and all the statistical methods used. Imposed passive movements also elicited mainly robust brain activation for individual and group activation maps, and reliability was improved by including additional force and range of motion using model 2. These findings demonstrate that the use of robotic devices, such as MaRIA, can be useful to reliably assess arm movement related brain activation in longitudinal studies and may contribute in studies evaluating therapies and brain plasticity following injury in the nervous system.

Broad chromosomal domains of histone modification patterns in C. elegans

PubMed Central

Liu, Tao; Rechtsteiner, Andreas; Egelhofer, Thea A.; Vielle, Anne; Latorre, Isabel; Cheung, Ming-Sin; Ercan, Sevinc; Ikegami, Kohta; Jensen, Morten; Kolasinska-Zwierz, Paulina; Rosenbaum, Heidi; Shin, Hyunjin; Taing, Scott; Takasaki, Teruaki; Iniguez, A. Leonardo; Desai, Arshad; Dernburg, Abby F.; Kimura, Hiroshi; Lieb, Jason D.; Ahringer, Julie; Strome, Susan; Liu, X. Shirley

2011-01-01

Chromatin immunoprecipitation identifies specific interactions between genomic DNA and proteins, advancing our understanding of gene-level and chromosome-level regulation. Based on chromatin immunoprecipitation experiments using validated antibodies, we define the genome-wide distributions of 19 histone modifications, one histone variant, and eight chromatin-associated proteins in Caenorhabditis elegans embryos and L3 larvae. Cluster analysis identified five groups of chromatin marks with shared features: Two groups correlate with gene repression, two with gene activation, and one with the X chromosome. The X chromosome displays numerous unique properties, including enrichment of monomethylated H4K20 and H3K27, which correlate with the different repressive mechanisms that operate in somatic tissues and germ cells, respectively. The data also revealed striking differences in chromatin composition between the autosomes and between chromosome arms and centers. Chromosomes I and III are globally enriched for marks of active genes, consistent with containing more highly expressed genes, compared to chromosomes II, IV, and especially V. Consistent with the absence of cytological heterochromatin and the holocentric nature of C. elegans chromosomes, markers of heterochromatin such as H3K9 methylation are not concentrated at a single region on each chromosome. Instead, H3K9 methylation is enriched on chromosome arms, coincident with zones of elevated meiotic recombination. Active genes in chromosome arms and centers have very similar histone mark distributions, suggesting that active domains in the arms are interspersed with heterochromatin-like structure. These data, which confirm and extend previous studies, allow for in-depth analysis of the organization and deployment of the C. elegans genome during development. PMID:21177964

Conformational dynamics of Peb4 exhibit "mother's arms" chain model: a molecular dynamics study.

PubMed

Dantu, Sarath Chandra; Khavnekar, Sagar; Kale, Avinash

2017-08-01

Peb4 from Campylobacter jejuni is an intertwined dimeric, periplasmic holdase, which also exhibits peptidyl prolyl cis/trans isomerase (PPIase) activity. Peb4 gene deletion alters the outer membrane protein profile and impairs cellular adhesion and biofilm formation for C. jejuni. Earlier crystallographic study has proposed that the PPIase domains are flexible and might form a cradle for holding the substrate and these aspects of Peb4 were explored using sub-microsecond molecular dynamics simulations in solution environment. Our simulations have revealed that PPIase domains are highly flexible and undergo a large structural change where they move apart from each other by 8 nm starting at .5 nm. Further, this large conformational change renders Peb4 as a compact protein with crossed-over conformation, forms a central cavity, which can "cradle" the target substrate. As reported for other chaperone proteins, flexibility of linker region connecting the chaperone and PPIase domains is key to forming the "crossed-over" conformation. The conformational transition of the Peb4 protein from the X-ray structure to the crossed-over conformation follows the "mother's arms" chain model proposed for the FkpA chaperone protein. Our results offer insights into how Peb4 and similar chaperones can use the conformational heterogeneity at their disposal to perform its much-revered biological function.

Beyond the Borders of a Galaxy

NASA Technical Reports Server (NTRS)

2008-01-01

[figure removed for brevity, see original site] Side-by-Side Comparison Click on image for larger view

The outlying regions around the Southern Pinwheel galaxy, or M83, are highlighted in this composite image from NASA's Galaxy Evolution Explorer and the National Science Foundation's Very Large Array in New Mexico. The blue and pink pinwheel in the center is the galaxy's main stellar disk, while the flapping, ribbon-like structures are its extended arms.

The Galaxy Evolution Explorer is an ultraviolet survey telescope. Its observations, shown here in blue and green, highlight the galaxy's farthest-flung clusters of young stars up to 140,000 light-years from its center. The Very Large Array observations show the radio emission in red. They highlight gaseous hydrogen atoms, or raw ingredients for stars, which make up the lengthy, extended arms.

Astronomers are excited that the clusters of baby stars match up with the extended arms, because this helps them better understand how stars can be created out in the 'backwoods' of a galaxy.

In this image, far-ultraviolet light is blue, near-ultraviolet light is green and radio emission at a wavelength of 21 centimeters is red.

What Lies Beyond the Edge of a Galaxy The side-by-side comparison shows the Southern Pinwheel galaxy, or M83, as seen in ultraviolet light (right) and at both ultraviolet and radio wavelengths (left). While the radio data highlight the galaxy's long, octopus-like arms stretching far beyond its main spiral disk (red), the ultraviolet data reveal clusters of baby stars (blue) within the extended arms.

The ultraviolet image was taken by NASA's Galaxy Evolution Explorer between March 15 and May 20, 2007, at scheduled intervals. Back in 2005, the telescope first photographed M83 over a shorter period of time. That picture was the first to reveal far-flung baby stars forming up to 63,000 light-years from the edge of the main spiral disk. This came as a surprise to astronomers because a galaxy's outer territory typically lacks high densities of star-forming materials.

The newest picture of M83 from the Galaxy Evolution Explorer is shown at the right, and was taken over a longer period of time. In fact, it is one of the 'deepest,' or longest-exposure, images of a nearby galaxy in ultraviolet light. This deeper view shows more clusters of stars, as well as stars in the very remote reaches of the galaxy, up to 140,000 light-years away from its core.

The view at the left is a combination of the ultraviolet picture at the right and data taken by the telescopes of the National Science Foundation's Very Large Array in New Mexico. The radio data, colored here in red, reveal extended galactic arms of gaseous hydrogen atoms, which are raw ingredients for stars. Astronomers are excited that the remote clusters of baby stars match up with the extended arms, because this helps them better understand how stars can be created out in the boondocks of a galaxy.

M83 is located 15 million light-years away in the southern constellation Hydra.

In the Galaxy Evolution Explorer image on the right, near-ultraviolet light (or longer-wavelength ultraviolet light) is colored yellow and far-ultraviolet light is blue. In the combined image at the left, far-ultraviolet light is blue, near-ultraviolet light is green, and the radio emission at a wavelength of 21 centimeters is red.

Effects of star-shape poly(alkyl methacrylate) arm uniformity on lubricant properties

DOE PAGES

Robinson, Joshua W.; Qu, Jun; Erck, Robert; ...

2016-03-29

Star-shaped poly(alkyl methacrylate)s (PAMAs) were prepared and blended into an additive-free engine oil to assess the structure property relationship between macromolecular structure and lubricant performance. These additives were designed with a comparable number of repeating units per arm and the number of arms was varied between 3 and 6. Well-defined star-shaped PAMAs were synthesized by atom transfer radical polymerization (ATRP) via a core-first strategy from multi-functional headgroups. Observations of the polymer-oil blends suggest that stars with less than four arms are favorable as a viscosity index improver (VII), and molecular weight dominates viscosity-related effects over other structural features. Star-shaped PAMAs,more » as oil additives, effectively reduce the friction coefficient in both mixed and boundary lubrication regime. Several analogs outperformed commercial VIIs in both viscosity and friction performance. Furthermore, increased wear rates were observed for these star-shaped PAMAs in the boundary lubrication regime suggesting pressure-sensitive conformations may exist.« less

Lunar surface operations. Volume 3: Robotic arm for lunar surface vehicle

NASA Technical Reports Server (NTRS)

Shields, William; Feteih, Salah; Hollis, Patrick

1993-01-01

A robotic arm for a lunar surface vehicle that can help in handling cargo and equipment, and remove obstacles from the path of the vehicle is defined as a support to NASA's intention to establish a lunar based colony by the year 2010. Its mission would include, but not limited to the following: exploration, lunar sampling, replace and remove equipment, and setup equipment (e.g. microwave repeater stations). Performance objectives for the robotic arm include a reach of 3 m, accuracy of 1 cm, arm mass of 100 kg, and lifting capability of 50 kg. The end effectors must grip various sizes and shapes of cargo; push, pull, turn, lift, or lower various types of equipment; and clear a path on the lunar surface by shoveling, sweeping aside, or gripping the obstacle present in the desired path. The arm can safely complete a task within a reasonable amount of time; the actual time is dependent upon the task to be performed. The positioning of the arm includes a manual backup system such that the arm can be safely stored in case of failure. Remote viewing and proximity and positioning sensors are incorporated in the design of the arm. The following specific topic are addressed in this report: mission and requirements, system design and integration, mechanical structure, modified wrist, structure-to-end-effector interface, end-effectors, and system controls.

Shaped nanocrystal particles and methods for making the same

DOEpatents

Alivisatos, A Paul [Oakland, CA; Scher, Erik C [Menlo Park, CA; Manna, Liberato [Berkeley, CA

2011-11-22

Shaped nanocrystal particles and methods for making shaped nanocrystal particles are disclosed. One embodiment includes a method for forming a branched, nanocrystal particle. It includes (a) forming a core having a first crystal structure in a solution, (b) forming a first arm extending from the core having a second crystal structure in the solution, and (c) forming a second arm extending from the core having the second crystal structure in the solution.

Shaped nanocrystal particles and methods for making the same

DOEpatents

Alivisatos, A. Paul; Scher, Erik C; Manna, Liberato

2013-12-17

Shaped nanocrystal particles and methods for making shaped nanocrystal particles are disclosed. One embodiment includes a method for forming a branched, nanocrystal particle. It includes (a) forming a core having a first crystal structure in a solution, (b) forming a first arm extending from the core having a second crystal structure in the solution, and (c) forming a second arm extending from the core having the second crystal structure in the solution.

Shaped nanocrystal particles and methods for working the same

DOEpatents

Alivisatos, A. Paul; Sher, Eric C.; Manna, Liberato

2007-12-25

Shaped nanocrystal particles and methods for making shaped nanocrystal particles are disclosed. One embodiment includes a method for forming a branched, nanocrystal particle. It includes (a) forming a core having a first crystal structure in a solution, (b) forming a first arm extending from the core having a second crystal structure in the solution, and (c) forming a second arm extending from the core having the second crystal structure in the solution.

Shaped Nonocrystal Particles And Methods For Making The Same

DOEpatents

Alivisatos, A. Paul; Scher, Erik C.; Manna, Liberato

2005-02-15

Shaped nanocrystal particles and methods for making shaped nanocrystal particles are disclosed. One embodiment includes a method for forming a branched, nanocrystal particle. It includes (a) forming a core having a first crystal structure in a solution, (b) forming a first arm extending from the core having a second crystal structure in the solution, and (c) forming a second arm extending from the core having the second crystal structure in the solution.

Bilateral movements increase sustained extensor force in the paretic arm.

PubMed

Kang, Nyeonju; Cauraugh, James H

2018-04-01

Muscle weakness in the extensors poststroke is a common motor impairment. Unfortunately, research is unclear on whether bilateral movements increase extensor force production in the paretic arm. This study investigated sustained force production while stroke individuals maximally extended their wrist and fingers on their paretic arm. Specifically, we determined isometric force production in three conditions: (a) unilateral paretic arm, (b) unilateral nonparetic arm, and (c) bilateral (both arms executing the same movement simultaneously). Seventeen chronic stroke patients produced isometric sustained force by executing wrist and fingers extension in unilateral and bilateral contraction conditions. Mean force, force variability (coefficient of variation), and signal-to-noise ratio were calculated for each contraction condition. Analysis of two-way (Arm × Type of Condition: 2 × 2; Paretic or Nonparetic Arm × Unilateral or Bilateral Conditions) within-subjects ANOVAs revealed that the bilateral condition increased sustained force in the paretic arm, but reduced sustained force in the nonparetic arm. Further, although the paretic arm exhibited more force variability and less signal-to-noise ratio than the nonparetic arm during a unilateral condition, there were no differences when participants simultaneously executed isometric contractions with both arms. Our unique findings indicate that bilateral contractions transiently increased extensor force in the paretic arm. Implications for Rehabilitation Bilateral movements increased isometric wrsit extensor force in paretic arms and redcued force in nonparetic arms versus unilateral movements. Both paretic and nonparetic arms produced similar force variability and signal-to-noise ratio during bilateral movements. Increased sustained force in the paretic arm during the bilateral condition indicates that rehabilitation protocols based on bilateral movements may be beneficial for functional recovery.

3D structure of eukaryotic flagella in a quiescent state revealed by cryo-electron tomography

PubMed Central

Nicastro, Daniela; McIntosh, J. Richard; Baumeister, Wolfgang

2005-01-01

We have used cryo-electron tomography to investigate the 3D structure and macromolecular organization of intact, frozen-hydrated sea urchin sperm flagella in a quiescent state. The tomographic reconstructions provide information at a resolution better than 6 nm about the in situ arrangements of macromolecules that are key for flagellar motility. We have visualized the heptameric rings of the motor domains in the outer dynein arm complex and determined that they lie parallel to the plane that contains the axes of neighboring flagellar microtubules. Both the material associated with the central pair of microtubules and the radial spokes display a plane of symmetry that helps to explain the planar beat pattern of these flagella. Cryo-electron tomography has proven to be a powerful technique for helping us understand the relationships between flagellar structure and function and the design of macromolecular machines in situ. PMID:16246999

KSC-02pd0390

NASA Image and Video Library

2002-04-03

KENNEDY SPACE CENTER, FLA. -- Space Shuttle Atlantis is revealed as the Rotating Service Structure rolls back into launch position. The RSS provides protected access to the orbiter for changeout and servicing of payloads at the pad. The structure has access platforms at five levels to provide access to the payload bay. The Shuttle rests on the Mobile Launcher Platform (MLP), which straddles the flame trench below. The flame trench is part of the Flame Deflector System that insulates pad structures from the intense heat of the launch. Above the golden external tank is the vent hood (known as the "beanie cap") at the end of the gaseous oxygen vent arm. Vapors are created as the liquid oxygen in the external tank boil off. The hood vents the gaseous oxygen vapors away from the Space Shuttle vehicle. Mission STS-110 is scheduled to launch April 4 on its 11-day mission to the International Space Station

Micromirror structure actuated by TiNi shape memory thin films

NASA Astrophysics Data System (ADS)

Fu, Y. Q.; Luo, J. K.; Hu, M.; Du, H. J.; Flewitt, A. J.; Milne, W. I.

2005-10-01

TiNi films were deposited by co-sputtering TiNi and Ti targets. Results from differential scanning calorimetry and curvature measurement revealed martensitic transformation and shape memory effect upon heating and cooling. Two types of TiNi/Si micromirror structures with a Si mirror cap (40 µm thick) and TiNi/Si actuation beams were designed and fabricated. For the first design, a V-shaped cantilever based on the TiNi/Si bimorph structure was used as the actuation mechanism for the micromirror. In the second design, three elbow-shaped Si beams with TiNi electrodes were used as the arms to actuate the mirror. The TiNi/Si microbeams were flat at room temperature and bent up by applying voltage in the TiNi electrodes (due to phase transformation and shape memory effect), thus causing changes in angles of the micromirror.

HK022 Nun Requires Arginine-Rich Motif Residues Distinct from λ N

PubMed Central

Tawk, Caroline S.; Ghattas, Ingrid R.

2015-01-01

ABSTRACT Bacteriophage λ N protein binds boxB RNA hairpins in the nut (N utilization) sites of immediate early λ transcripts and interacts with host factors to suppress transcriptional termination at downstream terminators. In opposition to λ N, the Nun protein of HK022 binds the boxBs of coinfecting λ transcripts, interacts with a similar or identical set of host factors, and terminates transcription to suppress λ replication. Comparison of N-boxB and Nun-boxB nuclear magnetic resonance (NMR) structural models suggests similar interactions, though limited mutagenesis of Nun is available. Here, libraries of Nun's arginine-rich motif (ARM) were screened for the ability to exclude λ coinfection, and mutants were assayed for Nun termination with a boxB plasmid reporter system. Several Nun ARM residues appear to be immutable: Asp26, Arg28, Arg29, Arg32, Trp33, and Arg36. Asp26 and Trp33 appear to be unable to contact boxB and are not found at equivalent positions in λ N ARM. To understand if the requirement of Asp26, Trp33, and Arg36 indicated differences between HK022 Nun termination and λ N antitermination complexes, the same Nun libraries were fused to the activation domain of λ N and screened for clones able to complement N-deficient λ. Mutants were assayed for N antitermination. Surprisingly, Asp26 and Trp33 were still essential when Nun ARM was fused to N. Docking suggests that Nun ARM contacts a hydrophobic surface of the NusG carboxy-terminal domain containing residues necessary for Nun function. These findings indicate that Nun ARM relies on distinct contacts in its ternary complex and illustrate how protein-RNA recognition can evolve new regulatory functions. IMPORTANCE λ N protein interacts with host factors to allow λ nut-containing transcripts to elongate past termination signals. A competing bacteriophage, HK022, expresses Nun protein, which causes termination of λ nut transcripts. λ N and HK022 Nun use similar arginine-rich motifs (ARMs) to bind the same boxB RNAs in nut transcripts. Screening libraries of Nun ARM mutants, both in HK022 Nun and in a λ N fusion, revealed amino acids essential to Nun that could bind one or more host factors. Docking suggests that NusG, which is present in both Nun termination and N antitermination, is a plausible partner. These findings could help understand how transcription elongation is regulated and illustrate how subtle differences allow ARMs to evolve new regulatory functions. PMID:26350130

HK022 Nun Requires Arginine-Rich Motif Residues Distinct from λ N.

PubMed

Tawk, Caroline S; Ghattas, Ingrid R; Smith, Colin A

2015-11-01

Bacteriophage λ N protein binds boxB RNA hairpins in the nut (N utilization) sites of immediate early λ transcripts and interacts with host factors to suppress transcriptional termination at downstream terminators. In opposition to λ N, the Nun protein of HK022 binds the boxBs of coinfecting λ transcripts, interacts with a similar or identical set of host factors, and terminates transcription to suppress λ replication. Comparison of N-boxB and Nun-boxB nuclear magnetic resonance (NMR) structural models suggests similar interactions, though limited mutagenesis of Nun is available. Here, libraries of Nun's arginine-rich motif (ARM) were screened for the ability to exclude λ coinfection, and mutants were assayed for Nun termination with a boxB plasmid reporter system. Several Nun ARM residues appear to be immutable: Asp26, Arg28, Arg29, Arg32, Trp33, and Arg36. Asp26 and Trp33 appear to be unable to contact boxB and are not found at equivalent positions in λ N ARM. To understand if the requirement of Asp26, Trp33, and Arg36 indicated differences between HK022 Nun termination and λ N antitermination complexes, the same Nun libraries were fused to the activation domain of λ N and screened for clones able to complement N-deficient λ. Mutants were assayed for N antitermination. Surprisingly, Asp26 and Trp33 were still essential when Nun ARM was fused to N. Docking suggests that Nun ARM contacts a hydrophobic surface of the NusG carboxy-terminal domain containing residues necessary for Nun function. These findings indicate that Nun ARM relies on distinct contacts in its ternary complex and illustrate how protein-RNA recognition can evolve new regulatory functions. λ N protein interacts with host factors to allow λ nut-containing transcripts to elongate past termination signals. A competing bacteriophage, HK022, expresses Nun protein, which causes termination of λ nut transcripts. λ N and HK022 Nun use similar arginine-rich motifs (ARMs) to bind the same boxB RNAs in nut transcripts. Screening libraries of Nun ARM mutants, both in HK022 Nun and in a λ N fusion, revealed amino acids essential to Nun that could bind one or more host factors. Docking suggests that NusG, which is present in both Nun termination and N antitermination, is a plausible partner. These findings could help understand how transcription elongation is regulated and illustrate how subtle differences allow ARMs to evolve new regulatory functions. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Ligand regulation of a constitutively dimeric EGF receptor

NASA Astrophysics Data System (ADS)

Freed, Daniel M.; Alvarado, Diego; Lemmon, Mark A.

2015-06-01

Ligand-induced receptor dimerization has traditionally been viewed as the key event in transmembrane signalling by epidermal growth factor receptors (EGFRs). Here we show that the Caenorhabditis elegans EGFR orthologue LET-23 is constitutively dimeric, yet responds to its ligand LIN-3 without changing oligomerization state. SAXS and mutational analyses further reveal that the preformed dimer of the LET-23 extracellular region is mediated by its domain II dimerization arm and resembles other EGFR extracellular dimers seen in structural studies. Binding of LIN-3 induces only minor structural rearrangements in the LET-23 dimer to promote signalling. Our results therefore argue that EGFR can be regulated by allosteric changes within an existing receptor dimer--resembling signalling by insulin receptor family members, which share similar extracellular domain compositions but form covalent dimers.

Complex Spiral Structure in the HD 100546 Transitional Disk as Revealed by GPI and MagAO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Follette, Katherine B.; Macintosh, Bruce; Mullen, Wyatt

We present optical and near-infrared high-contrast images of the transitional disk HD 100546 taken with the Magellan Adaptive Optics system (MagAO) and the Gemini Planet Imager (GPI). GPI data include both polarized intensity and total intensity imagery, and MagAO data are taken in Simultaneous Differential Imaging mode at H α . The new GPI H -band total intensity data represent a significant enhancement in sensitivity and field rotation compared to previous data sets and enable a detailed exploration of substructure in the disk. The data are processed with a variety of differential imaging techniques (polarized, angular, reference, and simultaneous differentialmore » imaging) in an attempt to identify the disk structures that are most consistent across wavelengths, processing techniques, and algorithmic parameters. The inner disk cavity at 15 au is clearly resolved in multiple data sets, as are a variety of spiral features. While the cavity and spiral structures are identified at levels significantly distinct from the neighboring regions of the disk under several algorithms and with a range of algorithmic parameters, emission at the location of HD 100546 “ c ” varies from point-like under aggressive algorithmic parameters to a smooth continuous structure with conservative parameters, and is consistent with disk emission. Features identified in the HD 100546 disk bear qualitative similarity to computational models of a moderately inclined two-armed spiral disk, where projection effects and wrapping of the spiral arms around the star result in a number of truncated spiral features in forward-modeled images.« less

How do the outcomes of the DEKA Arm compare to conventional prostheses?

PubMed

Resnik, Linda J; Borgia, Matthew L; Acluche, Frantzy; Cancio, Jill M; Latlief, Gail; Sasson, Nicole

2018-01-01

Objectives were to 1) compare self-reported function, dexterity, activity performance, quality of life and community integration of the DEKA Arm to conventional prostheses; and 2) examine differences in outcomes by conventional prosthesis type, terminal device type and by DEKA Arm configuration level. This was a two-part study; Part A consisted of in-laboratory training. Part B consisted of home use. Study participants were 23 prosthesis users (mean age = 45 ± 16; 87% male) who completed Part A, and 15 (mean age = 45 ± 18; 87% male) who completed Parts A and B. Outcomes including self-report and performance measures, were collected at Baseline using participants' personal prostheses and at the End of Parts A and B. Scores were compared using paired t-tests. Wilcoxon signed-rank tests were used to compare outcomes for the full sample, and for the sample stratified by device and terminal device type. Analysis of outcomes by configuration level was performed graphically. At the End of Part A activity performance using the DEKA Arm and conventional prosthesis was equivalent, but slower with the DEKA Arm. After Part B, performance using the DEKA Arm surpassed conventional prosthesis scores, and speed of activity completion was equivalent. Participants reported using the DEKA Arm to perform more activities, had less perceived disability, and less difficulty in activities at the End of A and B as compared to Baseline. No differences were observed in dexterity, prosthetic skill, spontaneity, pain, community integration or quality of life. Comparisons stratified by device type revealed similar patterns. Graphic comparisons revealed variations by configuration level. Participants using the DEKA Arm had less perceived disability and more engagement of the prosthesis in everyday tasks, although activity performance was slower. After home use experience, activity performance was improved and activity speed equivalent to using conventional prostheses.

Constraints on arm selection processes when reaching: degrees of freedom and joint amplitudes interact to influence limb selection.

PubMed

Kim, Wondae; Buchanan, John; Gabbard, Carl

2011-01-01

With an interest in identifying the variables that constrain arm choice when reaching, the authors had 11 right-handed participants perform free-choice and assigned-limb reaches at 9 object positions. The right arm was freely selected 100% of the time when reaching to positions at 30° and 40° into right hemispace. However, the left arm was freely selected to reach to positions at -30° and -40° in left hemispace 85% of the time. A comparison between free- and assigned-limb reaching kinematics revealed that free limb selection when reaching to the farthest positions was constrained by joint amplitude requirements and the time devoted to limb deceleration. Differences between free- and assigned-arm reaches were not evident when reaching to the midline and positions of ±10°, even though the right arm was freely selected most often for these positions. Different factors contribute to limb selection as a function of distance into a specific hemispace.

Simultaneous transcriptome analysis of Colletotrichum gloeosporioides and tomato fruit pathosystem reveals novel fungal pathogenicity and fruit defense strategies.

PubMed

Alkan, Noam; Friedlander, Gilgi; Ment, Dana; Prusky, Dov; Fluhr, Robert

2015-01-01

The fungus Colletotrichum gloeosporioides breaches the fruit cuticle but remains quiescent until fruit ripening signals a switch to necrotrophy, culminating in devastating anthracnose disease. There is a need to understand the distinct fungal arms strategy and the simultaneous fruit response. Transcriptome analysis of fungal-fruit interactions was carried out concurrently in the appressoria, quiescent and necrotrophic stages. Conidia germinating on unripe fruit cuticle showed stage-specific transcription that was accompanied by massive fruit defense responses. The subsequent quiescent stage showed the development of dendritic-like structures and swollen hyphae within the fruit epidermis. The quiescent fungal transcriptome was characterized by activation of chromatin remodeling genes and unsuspected environmental alkalization. Fruit response was portrayed by continued highly integrated massive up-regulation of defense genes. During cuticle infection of green or ripe fruit, fungi recapitulate the same developmental stages but with differing quiescent time spans. The necrotrophic stage showed a dramatic shift in fungal metabolism and up-regulation of pathogenicity factors. Fruit response to necrotrophy showed activation of the salicylic acid pathway, climaxing in cell death. Transcriptome analysis of C. gloeosporioides infection of fruit reveals its distinct stage-specific lifestyle and the concurrent changing fruit response, deepening our perception of the unfolding fungal-fruit arms and defenses race. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Displacement and deformation measurement for large structures by camera network

NASA Astrophysics Data System (ADS)

Shang, Yang; Yu, Qifeng; Yang, Zhen; Xu, Zhiqiang; Zhang, Xiaohu

2014-03-01

A displacement and deformation measurement method for large structures by a series-parallel connection camera network is presented. By taking the dynamic monitoring of a large-scale crane in lifting operation as an example, a series-parallel connection camera network is designed, and the displacement and deformation measurement method by using this series-parallel connection camera network is studied. The movement range of the crane body is small, and that of the crane arm is large. The displacement of the crane body, the displacement of the crane arm relative to the body and the deformation of the arm are measured. Compared with a pure series or parallel connection camera network, the designed series-parallel connection camera network can be used to measure not only the movement and displacement of a large structure but also the relative movement and deformation of some interesting parts of the large structure by a relatively simple optical measurement system.

Detachment of Tertiary Dendrite Arms during Controlled Directional Solidification in Aluminum - 7 wt Percent Silicon Alloys: Observations from Ground-based and Microgravity Processed Samples

NASA Technical Reports Server (NTRS)

Grugel, Richard N.; Erdman, Robert; Van Hoose, James R.; Tewari, Surendra; Poirier, David

2012-01-01

Electron Back Scattered Diffraction results from cross-sections of directionally solidified aluminum 7wt% silicon alloys unexpectedly revealed tertiary dendrite arms that were detached and mis-oriented from their parent arm. More surprisingly, the same phenomenon was observed in a sample similarly processed in the quiescent microgravity environment aboard the International Space Station (ISS) in support of the joint US-European MICAST investigation. The work presented here includes a brief introduction to MICAST and the directional solidification facilities, and their capabilities, available aboard the ISS. Results from the ground-based and microgravity processed samples are compared and possible mechanisms for the observed tertiary arm detachment are suggested.

Enhanced bioactivity of internally functionalized cationic dendrimers with PEG cores

PubMed Central

Albertazzi, Lorenzo; Mickler, Frauke M.; Pavan, Giovanni M.; Salomone, Fabrizio; Bardi, Giuseppe; Panniello, Mariangela; Amir, Elizabeth; Kang, Taegon; Killops, Kato L.; Bräuchle, Christoph; Amir, Roey J.; Hawker, Craig J.

2012-01-01

Hybrid dendritic-linear block copolymers based on a 4-arm polyethylene glycol (PEG) core were synthesized using an accelerated AB2/CD2 dendritic growth approach through orthogonal amine/epoxy and thiol-yne chemistries. The biological activity of these 4-arm and the corresponding 2-arm hybrid dendrimers revealed an enhanced, dendritic effect with an exponential increase in cell internalization concomitant with increasing amine end-groups and low cytotoxicity. Furthermore, the ability of these hybrid dendrimers to induce endosomal escape combined with their facile and efficient synthesis makes them attractive platforms for gene transfection. The 4-arm-based dendrimer showed significantly improved DNA binding and gene transfection capabilities in comparison with the 2-arm derivative. These results combined with the MD simulation indicate a significant effect of both the topology of the PEG core and the multivalency of these hybrid macromolecules, on their DNA binding and delivery capablities. PMID:23140570

Structure and activation of pro-activin A

PubMed Central

Wang, Xuelu; Fischer, Gerhard; Hyvönen, Marko

2016-01-01

Activins are growth factors with multiple roles in the development and homeostasis. Like all TGF-β family of growth factors, activins are synthesized as large precursors from which mature dimeric growth factors are released proteolytically. Here we have studied the activation of activin A and determined crystal structures of the unprocessed precursor and of the cleaved pro-mature complex. Replacing the natural furin cleavage site with a HRV 3C protease site, we show how the protein gains its bioactivity after proteolysis and is as active as the isolated mature domain. The complex remains associated in conditions used for biochemical analysis with a dissociation constant of 5 nM, but the pro-domain can be actively displaced from the complex by follistatin. Our high-resolution structures of pro-activin A share features seen in the pro-TGF-β1 and pro-BMP-9 structures, but reveal a new oligomeric arrangement, with a domain-swapped, cross-armed conformation for the protomers in the dimeric protein. PMID:27373274

Astronauts Bob Behnken and Eric Boe walk the Crew Access Arm at

NASA Image and Video Library

2017-08-30

Astronauts Bob Behnken, left, and Eric Boe walk down the Crew Access Arm being built by SpaceX for Launch Complex 39A at NASA’s Kennedy Space Center in Florida. The access arm will be installed on the launch pad, providing a bridge between the launch tower it’s the Fixed Service Structure, as noted below, and SpaceX’s Dragon 2 spacecraft for astronauts flying to the International Space Station on the company’s Falcon 9 rocket as part of NASA’s Commercial Crew Program. The access arm is being readied for installation in early 2018. It will be installed 70 feet higher than the former space shuttle access arm on the launch pad’s Fixed Service Structure. SpaceX continues to modify the historic launch site from its former space shuttle days, removing more than 500,000 pounds of steel from the pad structure, including the Rotating Service Structure that was once used for accessing the payload bay of the shuttle. SpaceX also is using the modernized site to launch commercial payloads, as well as cargo resupply missions to and from the International Space Station for NASA. The first SpaceX launch from the historic Apollo and space shuttle site was this past February. NASA’s Commercial Crew Program is working with private companies, Boeing and SpaceX, with a goal of once again flying people to and from the International Space Station, launching from the United States.

Initial experiments in thrusterless locomotion control of a free-flying robot

NASA Technical Reports Server (NTRS)

Jasper, W. J.; Cannon, R. H., Jr.

1990-01-01

A two-arm free-flying robot has been constructed to study thrusterless locomotion in space. This is accomplished by pushing off or landing on a large structure in a coordinated two-arm maneuver. A new control method, called system momentum control, allows the robot to follow desired momentum trajectories and thus leap or crawl from one structure to another. The robot floats on an air-cushion, simulating in two dimensions the drag-free zero-g environment of space. The control paradigm has been verified experimentally by commanding the robot to push off a bar with both arms, rotate 180 degrees, and catch itself on another bar.

Revisiting the substrate specificity of mammalian α1,6-fucosyltransferase reveals that it catalyzes core fucosylation of N-glycans lacking α1,3-arm GlcNAc.

PubMed

Yang, Qiang; Zhang, Roushu; Cai, Hui; Wang, Lai-Xi

2017-09-08

The mammalian α1,6-fucosyltransferase (FUT8) catalyzes the core fucosylation of N -glycans in the biosynthesis of glycoproteins. Previously, intensive in vitro studies with crude extract or purified enzyme concluded that the attachment of a GlcNAc on the α1,3 mannose arm of N -glycan is essential for FUT8-catalyzed core fucosylation. In contrast, we have recently shown that expression of erythropoietin in a GnTI knock-out, FUT8-overexpressing cell line results in the production of fully core-fucosylated glycoforms of the oligomannose substrate Man 5 GlcNAc 2 , suggesting that FUT8 can catalyze core fucosylation of N -glycans lacking an α1,3-arm GlcNAc in cells. Here, we revisited the substrate specificity of FUT8 by examining its in vitro activity toward an array of selected N -glycans, glycopeptides, and glycoproteins. Consistent with previous studies, we found that free N -glycans lacking an unmasked α1,3-arm GlcNAc moiety are not FUT8 substrates. However, Man 5 GlcNAc 2 glycan could be efficiently core-fucosylated by FUT8 in an appropriate protein/peptide context, such as with the erythropoietin protein, a V3 polypeptide derived from HIV-1 gp120, or a simple 9-fluorenylmethyl chloroformate-protected Asn moiety. Interestingly, when placed in the V3 polypeptide context, a mature bi-antennary complex-type N -glycan also could be core-fucosylated by FUT8, albeit at much lower efficiency than the Man 5 GlcNAc 2 peptide. This study represents the first report of in vitro FUT8-catalyzed core fucosylation of N -glycans lacking the α1,3-arm GlcNAc moiety. Our results suggest that an appropriate polypeptide context or other adequate structural elements in the acceptor substrate could facilitate the core fucosylation by FUT8. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Creating Access Points to Instrument-Based Atmospheric Data: Perspectives from the ARM Metadata Manager

NASA Astrophysics Data System (ADS)

Troyan, D.

2016-12-01

The Atmospheric Radiation Measurement (ARM) program has been collecting data from instruments in diverse climate regions for nearly twenty-five years. These data are made available to all interested parties at no cost via specially designed tools found on the ARM website (www.arm.gov). Metadata is created and applied to the various datastreams to facilitate information retrieval using the ARM website, the ARM Data Discovery Tool, and data quality reporting tools. Over the last year, the Metadata Manager - a relatively new position within the ARM program - created two documents that summarize the state of ARM metadata processes: ARM Metadata Workflow, and ARM Metadata Standards. These documents serve as guides to the creation and management of ARM metadata. With many of ARM's data functions spread around the Department of Energy national laboratory complex and with many of the original architects of the metadata structure no longer working for ARM, there is increased importance on using these documents to resolve issues from data flow bottlenecks and inaccurate metadata to improving data discovery and organizing web pages. This presentation will provide some examples from the workflow and standards documents. The examples will illustrate the complexity of the ARM metadata processes and the efficiency by which the metadata team works towards achieving the goal of providing access to data collected under the auspices of the ARM program.

Awareness of and memory for arm weakness during intracarotid sodium amytal testing.

PubMed

Carpenter, K; Berti, A; Oxbury, S; Molyneux, A J; Bisiach, E; Oxbury, J M

1995-02-01

The traditional association between anosognosia for hemiplegia and the right hemisphere was investigated in 31 patients with unilateral temporal lobe pathology during intracarotid sodium amytal testing (ISA) before epilepsy surgery. Recall of arm weakness was examined by questioning at the end of the test, when memory for items presented during the hemiplegia was also examined. Significantly more patients were amnesic for left arm weakness than for right. Amnesia for right arm weakness (and speech arrest) was significantly associated with pathology in the temporal lobe on the non-injected side and with impaired recognition of the memory items. Amnesia for left arm weakness was independent of both. Examination of cases where injection was contralateral to a hemisphere without pathology, and which showed normal memory capacity under ISA conditions, revealed that 87% recalled right arm weakness, but only 22% recalled left arm weakness. Awareness of arm weakness during left hemiplegia was examined in nine patients. Five of them were not aware of the weakness. Three of the four others could not subsequently recall it. By inference from the generally unimpaired recall of right arm weakness, following left hemisphere inactivation by amytal, an intact right hemisphere is capable of both recognizing right arm weakness and mediating its subsequent recall. In contrast, the left hemisphere was aware of left arm weakness only in approximately 50% of cases and even when there had been awareness usually could not mediate its subsequent recall. The suggestion is made that the right hemisphere may have a specific mnestic function for arm weakness, and presumably for hemiplegia, additional to the gnostic function.

High-contrast imaging of the close environment of HD 142527. VLT/NaCo adaptive optics thermal and angular differential imaging

NASA Astrophysics Data System (ADS)

Rameau, J.; Chauvin, G.; Lagrange, A.-M.; Thébault, P.; Milli, J.; Girard, J. H.; Bonnefoy, M.

2012-10-01

Context. It has long been suggested that circumstellar disks surrounding young stars may be the signposts of planets, and even more so since the recent discoveries of embedded substellar companions. According to models, the planet-disk interaction may create large structures, gaps, rings, or spirals in the disk. In that sense, the Herbig star HD 142527 is particularly compelling, as its massive disk displays intriguing asymmetries that suggest the existence of a dynamical peturber of unknown nature. Aims: Our goal was to obtain deep thermal images of the close circumstellar environment of HD 142527 to re-image the reported close-in structures (cavity, spiral arms) of the disk and to search for stellar and substellar companions that could be connected to their presence. Methods: We obtained high-contrast images with the NaCo adaptive optics system at the Very Large Telescope in L'-band. We applied different analysis strategies using both classical PSF-subtraction and angular differential imaging to probe for any extended structures or point-like sources. Results: The circumstellar environment of HD 142527 is revealed at an unprecedented spatial resolution down to the subarcsecond level for the first time at 3.8 μm. Our images reveal important radial and azimuthal asymmetries that invalidate an elliptical shape for the disk. It instead suggests a bright inhomogeneous spiral arm plus various fainter spiral arms. We also confirm an inner cavity down to 30 AU and two important dips at position angles of 0 and 135 deg. The detection performance in angular differential imaging enables exploration of the planetary mass regime for projected physical separations as close as 40 AU. Use of our detection map together with Monte Carlo simulations sets stringent constraints on the presence of planetary mass, brown dwarf or stellar companions as a function of the semi-major axis. They severely limit any presence of massive giant planets with semi-major axis beyond 50 AU, i.e. probably within the large disk's cavity which extends radially up to 145 AU or even farther outside. Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere, Chile, ESO: run 087.C-0299A.Reduced images are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/546/A24

M825A1 White Phosphorous Malfunction Investigation Related to the M739/ M739A1 Safing and Arming Module

DTIC Science & Technology

1993-08-01

AD-A269 205 AD AD-E402 378 Technical Report ARAED-TR-92031 M825A1 WHITE PHOSPHOROUS MALFUNCTION INVESTIGATION RELATED TO THE M739 /M739A1 SAFING AND...Aug 1993 - 4. TITLE AND SUBTITLE 5 FUNDING NUMBERS M825A1 WHITE PHOSPHOROUS MALFUNCTION INVESTIGATION RELATED TO THE M739 /M739AI SAFING AND ARMING...LT). An investigation of the data revealed changes in the burster and the M739 /M739A1 safing and arming (S&A) module. The Armaments Research

A comparative study of the N-linked oligosaccharide structures of human IgG subclass proteins.

PubMed Central

Jefferis, R; Lund, J; Mizutani, H; Nakagawa, H; Kawazoe, Y; Arata, Y; Takahashi, N

1990-01-01

Quantitative oligosaccharide profiles were determined for each of 18 human IgG paraproteins representing the four subclasses. Each paraprotein exhibits a unique profile that may be substantially different from that observed for polyclonal IgG. The IgG2 and some IgG3 proteins analysed exhibit a predominance of oligosaccharide moieties having galactose on the Man(alpha 1----3) arm rather than the Man(alpha 1----6) arm; it was previously held that galactosylation of the Man(alpha 1----6) arm is preferred, as observed for IgG1, IgG4 and polyclonal IgG. An IgG4 protein is reported that has galactosylated Man(alpha 1----3) and Man(alpha 1----6) arms on both Fc-localized carbohydrate moieties; previous findings suggested that such fully glycosylated structures could not be accommodated within the internal space of the C gamma 2 domains. Unusual monoantennary oligosaccharides present in IgG2 and IgG3 proteins were isolated and their structures determined. Images Fig. 1. PMID:2363690

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinez-Medina, L. A.; Pichardo, B.; Moreno, E.

We present a dynamical study of the effect of the bar and spiral arms on the simulated orbits of open clusters in the Galaxy. Specifically, this work is devoted to the puzzling presence of high-altitude open clusters in the Galaxy. For this purpose we employ a very detailed observationally motivated potential model for the Milky Way and a careful set of initial conditions representing the newly born open clusters in the thin disk. We find that the spiral arms are able to raise an important percentage of open clusters (about one-sixth of the total employed in our simulations, depending onmore » the structural parameters of the arms) above the Galactic plane to heights beyond 200 pc, producing a bulge-shaped structure toward the center of the Galaxy. Contrary to what was expected, the spiral arms produce a much greater vertical effect on the clusters than the bar, both in quantity and height; this is due to the sharper concentration of the mass on the spiral arms, when compared to the bar. When a bar and spiral arms are included, spiral arms are still capable of raising an important percentage of the simulated open clusters through chaotic diffusion (as tested from classification analysis of the resultant high-z orbits), but the bar seems to restrain them, diminishing the elevation above the plane by a factor of about two.« less

What Shaped Elias 2-27's Disk?

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2017-04-01

The young star Elias 2-27 is surrounded by a massive disk with spectacular spiral arms. A team of scientists from University of Cambridges Institute of Astronomy has now examined what might cause this disks appearance.Top: ALMA 1.3-mm observations of Elias 2-27s spiral arms, processed with an unsharp masking filter. Two symmetric spiral arms, a bright inner ellipse, and two dark crescents are clearly visible. Bottom: a deprojection of the top image (i.e., what the system would look like face-on). [Meru et al. 2017]ALMA-Imaged Spiral ArmsWith the dawn of new telescopes such as the Atacama Large Millimeter/submillimeter Array, were now able to study the birth of young stars and their newly forming planetary systems in more detail than ever before. But these new images require new models and interpretations!Case in point: Elias 2-27 is a low-mass star thats only a million years old and is surrounded by an unusually massive disk of gas and dust. Recent spatially-resolved ALMA observations of Elias 2-27 have revealed the stunning structure of the stars disk: it contains two enormous, symmetric spiral arms, as well as additional features interior to the spirals.What caused the disk to develop this structure? Led by Farzana Meru, a group of Institute of Astronomy researchers has run a series of simulations that explore different ways that Elias 2-27s disk might have evolved into the shape we see today.Modeling a DiskMeru and collaborators performed a total of 72 three-dimensional smoothed particle hydrodynamics simulations tracking 250,000 gas particles in a model disk around a star like Elias 2-27. They then modeled the transfer of energy through these simulated disks and produced synthetic ALMA observations based on the outcomes.Left: Synthetic ALMA observations of disks shaped by an internal companion (top), an external companion (middle), and gravitational instability within the disk (bottom). Right: Deprojections of the images on the left. Scales are the same as in the actual observations above. The external companion and the gravitational instability scenarios match the actual ALMA observations of Elias 2-27 well. [Adapted from Meru et al. 2017]By comparing these synthetic observations to the true ALMA observations of Elias 2-27, the authors hoped to determine which of three possible scenarios could produce the disk shape we see: 1) a companion (a planet or star) internal to the spiral arms, 2) a companion external to the spirals, or 3) gravitational instabilities operating within the disk.Gravity or a Companion?Meru and collaborators find that two scenarios produce observations that are very similar to what ALMA imaged. In the first, the disk is so massive that it becomes gravitationally unstable. Self-gravity of the disk then forms the spiral structures. In the second scenario, the arms are formed by a planetary companion of up to 1013 Jupiter masses orbiting Elias 2-27 outside of the spiral arms, at a large distance roughly in the range of 300700 AU.Though the possible companion inside the spiral arms is ruled out, the scenarios of a gravitational instability or an external companion remain plausible. If the former is true, then Elias 2-27 would be one of the first examples of an observed self-gravitating disk. If the latter is true, then Elias 2-27s disk likely fragmented recently, forming the giant planet thatshapesthe disk. This would be the first evidence for a disk that has fragmented into planetary-mass objects.Future deep near-infrared imaging may offer the chance to distinguish between these scenarios by allowing us to search for the heat from the possible companion.CitationF. Meru et al 2017ApJL 839 L24. doi:10.3847/2041-8213/aa6837

KSC01pp0275

NASA Image and Video Library

2001-02-07

This closeup reveals Space Shuttle Atlantis after rollback of the Rotating Service Structure. Extended to the side of Atlantis is the orbiter access arm, with the White Room at its end. The White Room provides entry for the crew into Atlantis’s cockpit. Below Atlantis, on either side of the tail, are the tail service masts. They support the fluid, gas and electrical requirements of the orbiter’s liquid oxygen and liquid hydrogen aft T-0 umbilicals. Atlantis is carrying the U.S. Laboratory Destiny, a key module in the growth of the International Space Station. Destiny will be attached to the Unity node on the Space Station using the Shuttle’s robotic arm. Three spacewalks are required to complete the planned construction work during the 11-day mission. Launch is targeted for 6:11 p.m. EST and the planned landing at KSC Feb. 18 about 1:39 p.m. This mission marks the seventh Shuttle flight to the Space Station, the 23rd flight of Atlantis and the 102nd flight overall in NASA’s Space Shuttle program

KSC01padig054

NASA Image and Video Library

2001-02-06

KENNEDY SPACE CENTER, Fla. -- This closeup reveals Space Shuttle Atlantis after rollback of the Rotating Service Structure. Extended to the side of Atlantis is the orbiter access arm, with the White Room at its end. The White Room provides entry for the crew into Atlantis’s cockpit. Below Atlantis, on either side of the tail are the tail service masts. They support the fluid, gas and electrical requirements of the orbiter’s liquid oxygen and liquid hydrogen aft T-0 umbilicals. Atlantis is carrying the U.S. Laboratory Destiny, a key module in the growth of the International Space Station. Destiny will be attached to the Unity node on the Space Station using the Shuttle’s robotic arm. Three spacewalks are required to complete the planned construction work during the 11-day mission. Launch is targeted for 6:11 p.m. EST and the planned landing at KSC Feb. 18 about 1:39 p.m. This mission marks the seventh Shuttle flight to the Space Station, the 23rd flight of Atlantis and the 102nd flight overall in NASA’s Space Shuttle program

Chironomus group classification according to the mapping of polytene chromosomes

NASA Astrophysics Data System (ADS)

Salleh, Syafinaz; Kutty, Ahmad Abas

2013-11-01

Chironomus is one of the important genera in Chironomidae family since they are widely diverse and abundance in aquatic ecosystem. Since Chironomus is very diverse, taxonomic work on this genus is very difficult and incomplete. Objective of this study is to form group classification of Chironomus according to the polytene chromosome mapping. The specific characteristics of polytene chromosomes in the salivary gland appeared to be particularly promising for taxonomic diagnosis of chironomid species. Chironomid larvae were collected from pristine sites at Sg. Langat and cultured in laboratory to reach fourth instar stage. The salivary glands were removed from larvae and chromosomes were stained with aceto orcein. Results showed that polytene chromosomes of Chironomus comprise of three long metacentric or submetacentric arms (BF, CD and AE arms) and one short acrocentric (G arm). In regards to nucleolar organizing region (NOR), Balbiani ring (BR), puffings and chromosome rearrangement, a number of four groups of different banding patterns were found. Two groups called as G group A and B have common NOR on arm BF and BR on arm G. However, group A has rearrangement pattern on arm CD and not in group B. This makes group B separated from group A. Another two groups called as groups C and D do not have common NOR on arm BF and also BR on arm G. Groups C and D were separated using arms G and arm AE. At arm G, only group C rearrangement pattern at unit 23c whereas group D was found to have large NOR at arm G and as well as arm AE, only group D has rearrangement pattern at unit 12c. This study indicates that chromosome arrangement could aid in revealing Chironomus diversity.

Exploring the Minispiral at the Milky Way's Center

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2017-06-01

An image of the continuum emission from the galactic center minispiral, previously taken by ALMA at 100 GHz. This image labels the structures of the minispiral: a bar and multiple arcing arms, andthe black hole Sgr A* near the center. [Tsuboi et al. 2017]The region around Sgr A*, the 4-million-solar-mass black hole at the heart of our galaxy, is a complex and dynamic place. New Atacama Large Millimeter/submillimeter Array (ALMA) observations of the Milky Ways center now reveal more about this harsh, inhospitable environment.A New ViewOne of the prominent structures at the heart of the Milky Way is a bundle of ionized gas streams located surrounding Sgr A* within the close distance of 6.5 light-years. These streams take the form of a bar and a series of arms that make it look much like a tiny spiral galaxy earning it the name of the galactic center minispiral.Where did this gas come from? Whats happening to it now? And what can it tell us about the environment about Sgr A*? A team of scientists led by Masato Tsuboi (Japan Aerospace Exploration Agency) has now obtained new ALMA images of the minispiral that are helping us to answer these questions.Electron temperature in K (numbers in yellow) and density in cm-3 (numbers in red) from the new ALMA observations of the ionized gas streamers. [Tsuboi et al. 2017]Clues from GasTsuboi and collaborators imaged the gas within the galactic center minispiral and its surroundings as part of the first ALMA observation cycle. This powerful telescopes images allowed the team to observe the streamers of ionized gas within the arms of the minispiral and determine their velocities. The authors were then able to use these measurements to identify which gas components are related and the speeds and directions of motion for the different components.Besides tracking the dynamics of the ionized gas in the minispiral, the team also confirmed that the electron temperatures and densities in the streamers increase with proximity to Sgr A*. We would expect these increases to cause the arms to expand laterally closer to the black hole but thats not whats observed. Instead, the arms remain closely confined.This discrepancy tells us something about the environment around the minispiral: there must be surrounding, ambient ionized gas thats pushing on the streamers, providing the external pressure to keep them confined.An Explanation for ProplydsThe ALMA observations of ionized gas (top panel) line up nicely with the JVLA detections of candidate proplyds near Sgr A* (bottom panel, with the ionized gas emission from the top panel shown as contours). [Tsuboi et al. 2017]Lastly, Tsuboi and collaborators compare their ALMA observations of the ionized gas in the minispiral with previous observations of the galactic center made with the Jansky Very Large Array. The JVLA observations revealed the presence of compact half-shell-like structures that may be proplyds protostars being photoevaporated by the hot radiation coming from the central star cluster around Sgr A*.These candidate proplyds have posed an astronomical puzzle: between Sgr A*s strong tidal forces and the radiation being emitted from the central star cluster, conditions are extremely inhospitable to star formation. So how did these proplyds get there?Tsuboi and collaborators observations may shed some light on this. Lining up the new ALMA images with the old JVLA ones, its clear that the proplyds are all concentrated along the ionized gas streamer of the northeastern arm in the minispiral. This suggests that the protostars may have formed further away from Sgr A*, and they were brought to their present-day location as the streamer fell inwards toward the black hole.CitationMasato Tsuboi et al 2017 ApJ 842 94. doi:10.3847/1538-4357/aa74e3

Multicompartmental Microcapsules from Star Copolymer Micelles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Ikjun; Malak, Sidney T.; Xu, Weinan

2013-02-26

We present the layer-by-layer (LbL) assembly of amphiphilic heteroarm pH-sensitive star-shaped polystyrene-poly(2-pyridine) (PSnP2VPn) block copolymers to fabricate porous and multicompartmental microcapsules. Pyridine-containing star molecules forming a hydrophobic core/hydrophilic corona unimolecular micelle in acidic solution (pH 3) were alternately deposited with oppositely charged linear sulfonated polystyrene (PSS), yielding microcapsules with LbL shells containing hydrophobic micelles. The surface morphology and internal nanopore structure of the hollow microcapsules were comparatively investigated for shells formed from star polymers with a different numbers of arms (9 versus 22) and varied shell thickness (5, 8, and 11 bilayers). The successful integration of star unimers into themore » LbL shells was demonstrated by probing their buildup, surface segregation behavior, and porosity. The larger arm star copolymer (22 arms) with stretched conformation showed a higher increment in shell thickness due to the effective ionic complexation whereas a compact, uniform grainy morphology was observed regardless of the number of deposition cycles and arm numbers. Small-angle neutron scattering (SANS) revealed that microcapsules with hydrophobic domains showed different fractal properties depending upon the number of bilayers with a surface fractal morphology observed for the thinnest shells and a mass fractal morphology for the completed shells formed with the larger number of bilayers. Moreover, SANS provides support for the presence of relatively large pores (about 25 nm across) for the thinnest shells as suggested from permeability experiments. The formation of robust microcapsules with nanoporous shells composed of a hydrophilic polyelectrolyte with a densely packed hydrophobic core based on star amphiphiles represents an intriguing and novel case of compartmentalized microcapsules with an ability to simultaneously store different hydrophilic, charged, and hydrophobic components within shells.« less

Domain-averaged, Shallow Precipitation Measurements During the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA)

NASA Astrophysics Data System (ADS)

Lamer, K.; Luke, E. P.; Kollias, P.; Oue, M.; Wang, J.

2017-12-01

The Atmospheric Radiation Measurement (ARM) Climate Research Facility operates a fixed observatory in the Eastern North Atlantic (ENA) on Graciosa Island in the Azores. Straddling the tropics and extratropics, the Azores receive air transported from North America, the Arctic and sometimes Europe. At the ARM ENA site, marine boundary layer clouds are frequently observed all year round. Estimates of drizzle mass flux from the surface to cloud base height are documented using a combination of high sensitivity profiling 35-GHz radar and ceilometer observations. Three years of drizzle mass flux retrievals reveal that statistically, directly over the ENA site, marine boundary layer cloud drizzle rates tend to be weak with few heavy drizzle events. In the summer of 2017, this site hosted the first phase of the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA) field campaign, which is motivated by the need for comprehensive in situ characterization of boundary layer structure, low clouds and aerosols. During this phase, the 35-GHz scanning ARM cloud radar was operated as a surveillance radar, providing regional context for the profiling observations. While less sensitive, the scanning radar measurements document a larger number of heavier drizzle events and provide domain-representative estimates of shallow precipitation. A best estimate, domain averaged, shallow precipitation rate for the region around the ARM ENA site is presented. The methodology optimally combines the ability of the profiling observations to detect the weak but frequently occurring drizzle events with the scanning cloud radar's ability to capture the less frequent heavier drizzle events. The technique is also evaluated using high resolution model output and a sophisticated forward radar operator.

A real-time robot arm collision avoidance system

NASA Technical Reports Server (NTRS)

Shaffer, Clifford A.; Herb, Gregory M.

1992-01-01

A data structure and update algorithm are presented for a prototype real-time collision avoidance safety system simulating a multirobot workspace. The data structure is a variant of the octree, which serves as a spatial index. An octree recursively decomposes 3D space into eight equal cubic octants until each octant meets some decomposition criteria. The N-objects octree, which indexes a collection of 3D primitive solids is used. These primitives make up the two (seven-degrees-of-freedom) robot arms and workspace modeled by the system. As robot arms move, the octree is updated to reflect their changed positions. During most update cycles, any given primitive does not change which octree nodes it is in. Thus, modification to the octree is rarely required. Cycle time for interpreting current arm joint angles, updating the octree to reflect new positions, and detecting/reporting imminent collisions averages 30 ms on an Intel 80386 processor running at 20 MHz.

An Integrated Geophysical and Tectonic Study of the Structure and Evolution of the Crust in the Snake River Plain Region, Pacific Northwest

NASA Astrophysics Data System (ADS)

Keller, G. R.; Khatiwada, M.

2016-12-01

The Snake River Plain region in the Pacific Northwest of North America has been the target of a number of recent studies that have revealed further complexities in its structure and tectonic evolution. Based on surface morphology and Late Cenozoic volcanic activity, the Snake River Plain consists of an eastern and western arm (ESRP and WSRP) that are similar in many respects but also quite different in other respects. Thus, its origin, evolution, structural complexities, the role of extension and magmatism in its formation, and the tectonic drivers are still subjects of debate. Numerous seismic studies have specifically focused on the structure of the ESRP and Yellowstone area. However, crustal-scale studies of the WSRP are limited. We added new gravity data to the existing coverage in the WSRP region and undertook a regional, integrated analysis approach that included magnetic, seismic reflection and refraction profiling, receiver function results, geological and geospatial data, and interpreted well logs. Our integrated geophysical modeling focused on the structure of the WSRP. We generated two crustal models across it at locations where the most existing geophysical and geological constraints were available. We observed both differences and similarities in the structure of the WSRP and ESRP. Although, the shallow crustal structures are different, a mid-crustal mafic intrusion is a major source of the high gravity anomaly values. Within the context of recent studies in the surrounding region, the intersection of the two arms of the Snake River Plain emerges as a major element of a complex tectonic intersection that includes the High Lava Plains of eastern Oregon, the Northern Nevada Rift, a southwestern extension of the ESRP into northern Nevada, as well as, faulting and volcanism extending northwestward to connect with the Columbia River Basalts region.

Structure of Irreversibly Adsorbed Star Polymers

NASA Astrophysics Data System (ADS)

Akgun, Bulent; Aykan, Meryem Seyma; Canavar, Seda; Satija, Sushil K.; Uhrig, David; Hong, Kunlun

Formation of irreversibly adsorbed polymer chains on solid substrates have a huge impact on the wetting, glass transition, aging and polymer chain mobility in thin films. In recent years there has been many reports on the formation, kinetics and dynamics of these layers formed by linear homopolymers. Recent studies showed that by varying the number of polymer arms and arm molecular weight one can tune the glass transition temperature of thin polymer films. Using polymer architecture as a tool, the behavior of thin films can be tuned between the behavior of linear chains and soft colloids. We have studied the effect of polymer chain architecture on the structure of dead layer using X-ray reflectivity (XR) and atomic force microscopy. Layer thicknesses and densities of flattened and loosely adsorbed chains has been measured for linear, 4-arm, and 8-arm star polymers with identical total molecular weight as a function of substrate surface energy, annealing temperature and annealing time. Star polymers have been synthesized using anionic polymerization. XR measurements showed that 8-arm star PS molecules form the densest and the thickest dead layers among these three molecules.

Control strategy for cooperating disparate manipulators

NASA Technical Reports Server (NTRS)

Lew, Jae Young

1989-01-01

To manipulate large payloads typical of space construction, the concept of a small arm mounted on the end of a large arm is introduced. The main purposes of such a configuration are to increase the structural stiffness of the robot by bracing against or locking to a stationary frame, and to maintain a firm position constraint between the robot's base and workpieces by grasping them. Possible topologies for a combination of disparate large and small arms are discussed, and kinematics, dynamics, controls, and coordination of the two arms, especially when they brace at the tip of the small arm, are developed. The feasibility and improvement in performance are verified, not only with analytical work and simulation results but also with experiments on the existing arrangement Robotic Arm Large and Flexible and Small Articulated Manipulator.

A new neural net approach to robot 3D perception and visuo-motor coordination

NASA Technical Reports Server (NTRS)

Lee, Sukhan

1992-01-01

A novel neural network approach to robot hand-eye coordination is presented. The approach provides a true sense of visual error servoing, redundant arm configuration control for collision avoidance, and invariant visuo-motor learning under gazing control. A 3-D perception network is introduced to represent the robot internal 3-D metric space in which visual error servoing and arm configuration control are performed. The arm kinematic network performs the bidirectional association between 3-D space arm configurations and joint angles, and enforces the legitimate arm configurations. The arm kinematic net is structured by a radial-based competitive and cooperative network with hierarchical self-organizing learning. The main goal of the present work is to demonstrate that the neural net representation of the robot 3-D perception net serves as an important intermediate functional block connecting robot eyes and arms.

Intraoperative brachial plexus injury during emergence following movement with arms restrained: a preventable complication?

PubMed Central

Chandler, Mark H; DiMatteo, Laura; Hasenboehler, Erik A; Temple, Michael

2007-01-01

Background Despite considerable analysis and preventive strategies, brachial plexus injuries remain fairly common in the perioperative setting. These injuries range from brief periods of numbness or discomfort in the immediate postoperative period to, in rare cases, profound, prolonged losses of sensation and function. We present a case of an orthopedic surgery patient who suffered a brachial plexus injury while under anesthesia after trying to sit upright with his arms restrained. Case presentation After the uneventful placement of an intramedullary tibial nail, an 18 year old patient tried to sit upright with his arms restrained while still under the influence of anesthesia. In the immediate postoperative period, the patient complained of a profound loss of sensation in his left arm and an inability to flex his left elbow, suppinate his arm, or abduct and rotate his shoulder. Neurological examination and subsequent studies revealed a C5-6 brachial plexus injury. The patient underwent range of motion physical therapy and, over the next three months, regained the full function and sensation of his left arm. Conclusion Restraining arms during general anesthesia to prevent injury remains a wise practice. However, to avoid injuring the brachial plexus while the arms are restrained, extra caution must be used to prevent unexpected patient movement and to ensure gentle emergence. PMID:18271944

Dimensions of operational stress and forms of unacceptable risk taking with small arms and munitions.

PubMed

Ben-Shalom, Uzi

2015-01-01

Accidents with small arms and munitions during deployment is a significant safety concern for leaders and safety specialists in combat units. Operational stress may lead to forms of unacceptable risk taking with small arms that may underlie some of these accidents. The present research studied the correlation between two dimensions of operational stress, two forms of risk taking with small arms among combat unit soldiers and possible mediators. The dimensions of operational threat, negative affect and personality profile from the EPQ-R-S were predictors; "exaggerated preparedness" and "risky games with small arms and munitions" were dependent variables; safety climate of the platoon served as a mediator variable. The participants were 461 compulsory service combat soldiers in 31 companies. This field study was conducted during period of top security alert. The results reveal that perceived threat is indeed correlated with exaggerated operational preparedness whereas general emotional state was correlated with risky games with small arms. Safety climate mediated only the correlation between general emotional state and risky games with small arms and munitions. Preparedness and risky games were predicted by the interaction of Psychoticism and the Lie Scale from the EPQ-R-S. The results may enhance the efforts in reducing risk taking and prevention of accidents with small arms and munitions during and following deployment.

A large, short-armed, winged dromaeosaurid (Dinosauria: Theropoda) from the Early Cretaceous of China and its implications for feather evolution.

PubMed

Lü, Junchang; Brusatte, Stephen L

2015-07-16

The famous 'feathered dinosaurs' from the Early Cretaceous of Liaoning Province, northeastern China, include several dromaeosaurids, which are among the closest relatives of birds. Most of these are small-bodied taxa with long arms and broad wings comprised of vaned feathers, but a single specimen (the holotype of Tianyuraptor) belongs to a much larger individual with reduced forelimbs, which unfortunately lacks any preserved integument. We describe a new specimen of large-bodied, short-armed Liaoning dromaeosaurid, which we designate as a new genus and species, Zhenyuanlong suni. The integument is well preserved and provides the first evidence of feather morphologies and distribution in a short-armed (and probably non-volant) dromaeosaurid, indicating that these rare and aberrant taxa had large wings consisting of pennaceous feathers on the arms and long pennaceous feathers on the tail very similar to their smaller and longer-armed relatives, but potentially lacked vaned feathers on the legs. Zhenyuanlong adds yet more diversity to the Liaoning dromaeosaurid fauna, helps further reveal a distinct short-armed bauplan among dromaeosaurids, and illuminates previously-unrecognized homoplasy that complicates dromaeosaurid phylogeny and suggests that the Liaoning taxa may not have formed their own clade.

Simulation of aerodynamic noise and vibration noise in hard disk drives

NASA Astrophysics Data System (ADS)

Zhu, Lei; Shen, Sheng-Nan; Li, Hui; Zhang, Guo-Qing; Cui, Fu-Hao

2018-05-01

Internal flow field characteristics of HDDs are usually influenced by the arm swing during seek operations. This, in turn, can affect aerodynamic noise and airflow-induced noise. In this paper, the dynamic mesh method is used to calculate the flow-induced vibration (FIV) by transient structure analysis and the boundary element method (BEM) is utilized to predict the vibration noise. Two operational states are considered: the arm is fixed and swinging over the disk. Both aerodynamic noise and vibration noise inside drives increase rapidly with increase in disk rotation and arm swing velocities. The largest aerodynamic noise source is always located near the arm and swung with the arm.

The RSS rolls back revealing STS-102 Discovery on Launch Pad 39B

NASA Technical Reports Server (NTRS)

2001-01-01

KENNEDY SPACE CENTER, Fla. - With the Rotating Service Structure rolled back, Space Shuttle Discovery is revealed, poised for launch on mission STS-102 at 6:42 a.m. EST March 8. It sits on the Mobile Launcher Platform, which straddles the flame trench below that helps deflect the intense heat of launch. Made of concrete and refractory brick, the trench is 490 feet long, 58 feet wide and 40 feet high. Situated above the external tank is the Gaseous Oxygen Vent Arm with the '''beanie cap,''' a vent hood. On this eighth construction flight to the International Space Station, Discovery carries the Multi-Purpose Logistics Module Leonardo, the primary delivery system used to resupply and return Station cargo requiring a pressurized environment. Leonardo will deliver up to 10 tons of laboratory racks filled with equipment, experiments and supplies for outfitting the newly installed U.S. Laboratory Destiny.

Localization of human coagulation factor VIII (hFVIII) in transgenic rabbit by FISH-TSA: identification of transgene copy number and transmission to the next generation.

PubMed

Krylov, V; Tlapáková, T; Mácha, J; Curlej, J; Ryban, L; Chrenek, P

2008-01-01

For chromosomal localization of the hFVIII human transgene in F2 and F3 generation of transgenic rabbits, FISH-TSA was applied. A short cDNA probe (1250 bp) targeted chromosomes 3, 7, 8, 9 and 18 of an F2 male (animal 1-3-8). Two transgenic offspring (F3) revealed signal positions in chromosome 3 and chromosomes 3 and 7, respectively. Sequencing and structure analysis of the rabbit orthologous gene revealed high similarity to its human counterpart. Part of the sequenced cDNA (1310 bp) served as a probe for FISH-TSA analysis. The rabbit gene was localized in the q arm terminus of the X chromosome. This result is in agreement with reciprocal chromosome painting between the rabbit and the human. The presented FISH-TSA method provides strong signals without any interspecies reactivity.

Model of outgrowths in the spiral galaxies NGC 4921 and NGC 7049 and the origin of spiral arms

NASA Astrophysics Data System (ADS)

Carlqvist, Per

2013-02-01

NGC 4921 and 7049 are two spiral galaxies presenting narrow, distinct dust features. A detailed study of the morphology of those features has been carried out using Hubble Space Telescope archival images. NGC 4921 shows a few but well-defined dust arms midway to its centre while NGC 7049 displays many more dusty features, mainly collected within a ring-shaped formation. Numerous dark and filamentary structures, called outgrowths, are found to protrude from the dusty arms in both galaxies. The outgrowths point both outwards and inwards in the galaxies. Mostly they are found to be V-shaped or Y-shaped with the branches connected to dark arm filaments. Often the stem of the Y appears to consist of intertwined filaments. Remarkably, the outgrowths show considerable similarities to elephant trunks in H ii regions. A model of the outgrowths, based on magnetized filaments, is proposed. The model provides explanations of both the shapes and orientations of the outgrowths. Most important, it can also give an account for their intertwined structures. It is found that the longest outgrowths are confusingly similar to dusty spiral arms. This suggests that some of the outgrowths can develop into such arms. The time-scale of the development is estimated to be on the order of the rotation period of the arms or shorter. Similar processes may also take place in other spiral galaxies. If so, the model of the outgrowths can offer a new approach to the old winding problem of spiral arms.

Colloidosomes formed by nonpolar/polar/nonpolar nanoball amphiphiles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Hung-Yu; Sheng, Yu-Jane, E-mail: yjsheng@ntu.edu.tw, E-mail: hktsao@cc.ncu.edu.tw; Tu, Sheng-Hung

2014-08-07

Fullerene-based amphiphiles are able to form bilayer vesicles in aqueous solution. In this study, the self-assembly behavior of polymer-tethered nanoballs (NBs) with nonpolar/polar/nonpolar (n-p-n{sup ′}) motif in a selective solvent is investigated by dissipative particle dynamics. A model NB bears two hydrophobic polymeric arms (n{sup ′}-part) tethered on an extremely hydrophobic NB (n-part) with hydrophilic patch (p-part) patterned on its surface. Dependent on the hydrophobicity and length of tethered arms, three types of aggregates are exhibited, including NB vesicle, core-shell micelle, and segmented-worm. NB vesicles are developed for a wide range of hydrophobic arm lengths. The presence of tethered armsmore » perturbs the bilayer structure formed by NBs. The structural properties including the order parameter, membrane thickness, and area density of the inner leaflet decrease with increasing the arm length. These results indicate that for NBs with longer arms, the extent of interdigitation in the membrane rises so that the overcrowded arms in the inner corona are relaxed. The transport and mechanical properties are evaluated as well. As the arm length grows, the permeability increases significantly because the steric bulk of tethered arms loosens the packing of NBs. By contrast, the membrane tension decreases owing to the reduction of NB/solvent contacts by the polymer corona. Although fusion can reduce membrane tension, NB vesicles show strong resistance to fusion. Moreover, the size-dependent behavior observed in small liposomes is not significant for NB vesicles due to isotropic geometry of NB. Our simulation results are consistent with the experimental findings.« less

Arm classification and velocity gradients in spiral galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biviano, A.; Girardi, M.; Giuricin, G.

1991-08-01

On the basis of published rotation curves, velocity gradients are compiled for 94 galaxies. A significant correlation is found in this sample of galaxies between their gradients and arm classes (as given by Elmegreen and Elmegreen, 1982); galaxies with steeper curves tend to have a flocculent arm structure, and galaxies with flatter curves tend to have a grand design morphology. The correlation is true, since it is not induced by other correlations. The present result is in agreement with previous suggestions by Whitmore (1984) and with the recent result by Elmegreen and Elmegreen; it is also consistent with the predictionsmore » of density wave theory for the formation of the spiral structure. 89 refs.« less

Computer coordination of limb motion for locomotion of a multiple-armed robot for space assembly

NASA Technical Reports Server (NTRS)

Klein, C. A.; Patterson, M. R.

1982-01-01

Consideration is given to a possible robotic system for the construction of large space structures, which may be described as a multiple general purpose arm manipulator vehicle that can walk over the structure under construction to a given site for further work. A description is presented of the locomotion of such a vehicle, modeling its arms in terms of a currently available industrial manipulator. It is noted that for whatever maximum speed of operation is chosen, rapid changes in robot velocity create situations in which already-selected handholds are no longer practical. A step is added to the 'free gait' walking algorithm in order to solve this problem.

Spiral Arm Morphology of Nearby Galaxies

NASA Astrophysics Data System (ADS)

Ann, Hong Bae; Lee, Hyun-Rok

2013-06-01

We analyze the spiral structure of 1725 nearby spiral galaxies with redshift less than 0.02. We use the color images provided by the Sloan Digital Sky Survey. We determine the arm classes (grand design, multiple-arm, flocculent) and the broad Hubble types (early, intermediate, late) as well as the bar types (SA, SAB, SB) by visual inspection. We find that flocculent galaxies are mostly of late Hubble type while multiple-arm galaxies are likely to be of early Hubble type. The fractional distribution of grand design galaxies is nearly constant along the Hubble type. The dependence of arm class on bar type is not as strong as that of the Hubble type. However, there is about a three times larger fraction of grand design spirals in SB galaxies than in SA galaxies, with nearly constant fractions of multiple-arm galaxies. However, if we consider the Hubble type and bar type together, grand design spirals are more frequent in early types than in late types for SA and SAB galaxies, while they are almost constant along the Hubble type for SB galaxies. There are clear correlations between spiral structures and the local background density: strongly barred, early-type, grand design spirals favor high-density regions, while non-barred, late-type, flocculent galaxies are likely to be found in low-density regions.

Shaping of arm configuration space by prescription of non-Euclidean metrics with applications to human motor control

NASA Astrophysics Data System (ADS)

Biess, Armin

2013-01-01

The study of the kinematic and dynamic features of human arm movements provides insights into the computational strategies underlying human motor control. In this paper a differential geometric approach to movement control is taken by endowing arm configuration space with different non-Euclidean metric structures to study the predictions of the generalized minimum-jerk (MJ) model in the resulting Riemannian manifold for different types of human arm movements. For each metric space the solution of the generalized MJ model is given by reparametrized geodesic paths. This geodesic model is applied to a variety of motor tasks ranging from three-dimensional unconstrained movements of a four degree of freedom arm between pointlike targets to constrained movements where the hand location is confined to a surface (e.g., a sphere) or a curve (e.g., an ellipse). For the latter speed-curvature relations are derived depending on the boundary conditions imposed (periodic or nonperiodic) and the compatibility with the empirical one-third power law is shown. Based on these theoretical studies and recent experimental findings, I argue that geodesics may be an emergent property of the motor system and that the sensorimotor system may shape arm configuration space by learning metric structures through sensorimotor feedback.

Recovery in the Severely Impaired Arm Post-stroke after Mirror Therapy - a Randomized Controlled Study.

PubMed

Chan, Wing Chiu; Au-Yeung, Stephanie Suk Yin

2018-03-09

This study aimed to examine the effectiveness of mirror therapy (MT) on recovery in the severely impaired arm after stroke. Using single-blind randomized controlled design, patients with severely impaired arm within 1-month post-stroke were assigned to received MT (n=20) or control therapy (CT) (n=21), 30min. twice daily for 4 weeks in addition to conventional rehabilitation. During MT and CT, subjects practiced similar structured exercises in both arms, except that mirror reflection of the unaffected arm was the visual feedback for MT, but mirror was absent for CT so that subjects could watch both arms in exercise. Fugl-Meyer Assessment (FMA) and Wolf Motor Function Test (WMFT) were the outcome measurements. After the intervention, both MT and CT groups had significant arm recovery similarly in FMA (p=0.867), WMFT-Time (p=0.947) and WMFT-Functional Ability Scale (p=0.676). MT or CT which involved exercises concurrently for the paretic and unaffected arms during subacute stroke promoted similar motor recovery in the severely impaired arm.

Central command increases muscular oxygenation of the non-exercising arm at the early period of voluntary one-armed cranking.

PubMed

Ishii, Kei; Matsukawa, Kanji; Asahara, Ryota; Liang, Nan; Endo, Kana; Idesako, Mitsuhiro; Michioka, Kensuke; Sasaki, Yu; Hamada, Hironobu; Yamashita, Kaori; Watanabe, Tae; Kataoka, Tsuyoshi; Takahashi, Makoto

2017-04-01

This study aimed to examine whether central command increases oxygenation in non-contracting arm muscles during contralateral one-armed cranking and whether the oxygenation response caused by central command differs among skeletal muscles of the non-exercising upper limb. In 13 male subjects, the relative changes in oxygenated-hemoglobin concentration (Oxy-Hb) of the non-contracting arm muscles [the anterior deltoid, triceps brachii, biceps brachii, and extensor carpi radialis (ECR)] were measured during voluntary one-armed cranking (intensity, 35-40% of maximal voluntary effort) and mental imagery of the one-armed exercise for 1 min. Voluntary one-armed cranking increased ( P  <   0.05) the Oxy-Hb of the triceps, biceps, and ECR muscles to the same extent (15 ± 4% of the baseline level, 17 ± 5%, and 16 ± 4%, respectively). The greatest increase in the Oxy-Hb was observed in the deltoid muscle. Intravenous injection of atropine (10-15  μ g/kg) and/or propranolol (0.1 mg/kg) revealed that the increased Oxy-Hb of the arm muscles consisted of the rapid atropine-sensitive and delayed propranolol-sensitive components. Mental imagery of the exercise increased the Oxy-Hb of the arm muscles. Motor-driven passive one-armed cranking had little influence on the Oxy-Hb of the arm muscles. It is likely that central command plays a role in the initial increase in oxygenation in the non-contracting arm muscles via sympathetic cholinergic vasodilatation at the early period of one-armed cranking. The centrally induced increase in oxygenation may not be different among the distal arm muscles but may augment in the deltoid muscle. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

A structured tool to improve clinical outcomes of Type 2 diabetes mellitus patients: A randomised controlled trial.

PubMed

Ayadurai, Shamala; Sunderland, V Bruce; Tee, Lisa Bg; Md Said, Siti Norlina; Hattingh, H Laetitia

2018-06-07

A review of pharmacist diabetes intervention studies revealed lack of structured process in providing diabetes care which consequently produced varied results from increased to minimal improvements. This study aimed to determine the effectiveness of a structured clinical guidelines tool, the Simpler™ tool, in the delivery of diabetes care. The primary outcome was significant improvement in HbA1c (glycated haemoglobin). Secondary outcomes were improved lipid profiles and blood pressure (BP). A 6-month, parallel, multi-centre, two arms, randomised controlled trial involving 14 pharmacists at seven primary care clinics was conducted in Johor, Malaysia. Pharmacists without prior specialised diabetes training were trained to use the tool. Patients were randomised within each centre to: 1) Simpler™ care (SC), receiving care from pharmacists who applied the tool (n=55); 2) Usual care (UC), receiving usual care and dispensing services (n=69). SC reduced HbA1c significantly by 1.59% (95%CI: -2.2, -0.9) compared to 0.25% (95%CI: -0.62, 0.11), (P=<0.001) in UC. In addition, SC patients had significantly improved systolic BP: (-6.28 mmHg (95%CI: -10.5, 2.0), p=0.005). The proportion of patients who reached the Malaysian guideline treatment goals were significantly more in the SC arm (14.3% vs 1.5% for HbA1c, p=0.020; 80% vs 42% for systolic BP, p=0.001; 60.5% vs 40.4% for LDL cholesterol, p=0.046). Use of the Simpler™ tool facilitated delivery of comprehensive evidence-based diabetes management and significantly improved clinical outcomes. The Simpler™ tool supported pharmacists in providing enhanced structured diabetes care. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Multiple Sex-Associated Regions and a Putative Sex Chromosome in Zebrafish Revealed by RAD Mapping and Population Genomics

PubMed Central

Anderson, Jennifer L.; Rodríguez Marí, Adriana; Braasch, Ingo; Amores, Angel; Hohenlohe, Paul; Batzel, Peter; Postlethwait, John H.

2012-01-01

Within vertebrates, major sex determining genes can differ among taxa and even within species. In zebrafish (Danio rerio), neither heteromorphic sex chromosomes nor single sex determination genes of large effect, like Sry in mammals, have yet been identified. Furthermore, environmental factors can influence zebrafish sex determination. Although progress has been made in understanding zebrafish gonad differentiation (e.g. the influence of germ cells on gonad fate), the primary genetic basis of zebrafish sex determination remains poorly understood. To identify genetic loci associated with sex, we analyzed F2 offspring of reciprocal crosses between Oregon *AB and Nadia (NA) wild-type zebrafish stocks. Genome-wide linkage analysis, using more than 5,000 sequence-based polymorphic restriction site associated (RAD-tag) markers and population genomic analysis of more than 30,000 single nucleotide polymorphisms in our *ABxNA crosses revealed a sex-associated locus on the end of the long arm of chr-4 for both cross families, and an additional locus in the middle of chr-3 in one cross family. Additional sequencing showed that two SNPs in dmrt1 previously suggested to be functional candidates for sex determination in a cross of ABxIndia wild-type zebrafish, are not associated with sex in our AB fish. Our data show that sex determination in zebrafish is polygenic and that different genes may influence sex determination in different strains or that different genes become more important under different environmental conditions. The association of the end of chr-4 with sex is remarkable because, unique in the karyotype, this chromosome arm shares features with known sex chromosomes: it is highly heterochromatic, repetitive, late replicating, and has reduced recombination. Our results reveal that chr-4 has functional and structural properties expected of a sex chromosome. PMID:22792396

Electron Tomography of Cryofixed, Isometrically Contracting Insect Flight Muscle Reveals Novel Actin-Myosin Interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Shenping; Liu, Jun; Reedy, Mary C.

2010-10-22

Isometric muscle contraction, where force is generated without muscle shortening, is a molecular traffic jam in which the number of actin-attached motors is maximized and all states of motor action are trapped with consequently high heterogeneity. This heterogeneity is a major limitation to deciphering myosin conformational changes in situ. We used multivariate data analysis to group repeat segments in electron tomograms of isometrically contracting insect flight muscle, mechanically monitored, rapidly frozen, freeze substituted, and thin sectioned. Improved resolution reveals the helical arrangement of F-actin subunits in the thin filament enabling an atomic model to be built into the thin filamentmore » density independent of the myosin. Actin-myosin attachments can now be assigned as weak or strong by their motor domain orientation relative to actin. Myosin attachments were quantified everywhere along the thin filament including troponin. Strong binding myosin attachments are found on only four F-actin subunits, the 'target zone', situated exactly midway between successive troponin complexes. They show an axial lever arm range of 77{sup o}/12.9 nm. The lever arm azimuthal range of strong binding attachments has a highly skewed, 127{sup o} range compared with X-ray crystallographic structures. Two types of weak actin attachments are described. One type, found exclusively in the target zone, appears to represent pre-working-stroke intermediates. The other, which contacts tropomyosin rather than actin, is positioned M-ward of the target zone, i.e. the position toward which thin filaments slide during shortening. We present a model for the weak to strong transition in the myosin ATPase cycle that incorporates azimuthal movements of the motor domain on actin. Stress/strain in the S2 domain may explain azimuthal lever arm changes in the strong binding attachments. The results support previous conclusions that the weak attachments preceding force generation are very different from strong binding attachments.« less

Mechanical impedance and absorbed power of hand-arm under x(h)-axis vibration and role of hand forces and posture.

PubMed

Aldien, Yasser; Marcotte, Pierre; Rakheja, Subhash; Boileau, Paul-Emile

2005-07-01

The biodynamic responses of the hand-arm system under x(h)-axis vibration are investigated in terms of the driving point mechanical impedance (DPMI) and absorbed power in a laboratory study. For this purpose, seven healthy male subjects are exposed to two levels of random vibration in the 8-1,000 Hz frequency range, using three instrumented cylindrical handles of different diameters (30, 40 and 50 mm), and different combinations of grip (10, 30 and 50 N) and push (0, 25 and 50 N) forces. The experiments involve grasping the handle while adopting two different postures, involving elbow flexion of 90 degrees and 180 degrees, with wrist in the neutral position for both postures. The analyses of the results revealed peak DPMI magnitude and absorbed power responses near 25 Hz and 150 Hz, for majority of the test conditions considered. The frequency corresponding to the peak response increased with increasing hand forces. Unlike the absorbed power, the DPMI response was mostly observed to be insensitive to variations in the excitation magnitude. The handle diameter revealed obvious effects on the DPMI magnitude, specifically at frequencies above 250 Hz, which was not evident in the absorbed power due to relatively low velocity at higher frequencies. The influence of hand forces was also evident on the DPMI magnitude response particularly at frequencies. above 100 Hz, while the effect of hand-arm posture on the DPMI magnitude was nearly negligible. The magnitude of power absorbed within the hand and arm was observed to be strongly dependent upon the excitation level over the entire frequency range, while the influence of hand-arm posture on the total absorbed power was observed to be important. The effect of variations in the hand forces on the absorbed power was relatively small for the bent elbow posture, while an increase in either the grip or the push force coupled with the extended arm posture resulted in considerably higher energy absorption. The results suggested that the handle size, hand-arm posture and hand forces, produce coupled effect on the biodynamic response of the hand-arm system.

In-situ observation of switchable nanoscale topography for y-shaped binary brushes in fluids.

PubMed

Lin, Yen-Hsi; Teng, Jing; Zubarev, Eugene R; Shulha, Hennady; Tsukruk, Vladimir V

2005-03-01

Direct, in-fluid observation of the surface morphology and nanomechanical properties of the mixed brushes composed of Y-shaped binary molecules PS-PAA revealed nanoscale network-like surface topography formed by coexisting stretched soluble PAA arms and collapsed insoluble PS chains in water. Placement of Y-shaped brushes in different fluids resulted in dramatic reorganization ranging from soft repellent layer covered by swollen PS arms in toluene to an adhesive, mixed layer composed of coexisting swollen PAA and collapsed PS arms in water. These binary layers with the overall nanoscale thickness can serve as adaptive nanocoatings with stimuli-responsive properties.

Galaxy Zoo: star formation versus spiral arm number

NASA Astrophysics Data System (ADS)

Hart, Ross E.; Bamford, Steven P.; Casteels, Kevin R. V.; Kruk, Sandor J.; Lintott, Chris J.; Masters, Karen L.

2017-06-01

Spiral arms are common features in low-redshift disc galaxies, and are prominent sites of star formation and dust obscuration. However, spiral structure can take many forms: from galaxies displaying two strong 'grand design' arms to those with many 'flocculent' arms. We investigate how these different arm types are related to a galaxy's star formation and gas properties by making use of visual spiral arm number measurements from Galaxy Zoo 2. We combine ultraviolet and mid-infrared (MIR) photometry from GALEX and WISE to measure the rates and relative fractions of obscured and unobscured star formation in a sample of low-redshift SDSS spirals. Total star formation rate has little dependence on spiral arm multiplicity, but two-armed spirals convert their gas to stars more efficiently. We find significant differences in the fraction of obscured star formation: an additional ˜10 per cent of star formation in two-armed galaxies is identified via MIR dust emission, compared to that in many-armed galaxies. The latter are also significantly offset below the IRX-β relation for low-redshift star-forming galaxies. We present several explanations for these differences versus arm number: variations in the spatial distribution, sizes or clearing time-scales of star-forming regions (I.e. molecular clouds), or contrasting recent star formation histories.

Goal driven kinematic simulation of flexible arm robot for space station missions

NASA Technical Reports Server (NTRS)

Janssen, P.; Choudry, A.

1987-01-01

Flexible arms offer a great degree of flexibility in maneuvering in the space environment. The problem of transporting an astronaut for extra-vehicular activity using a space station based flexible arm robot was studied. Inverse kinematic solutions of the multilink structure were developed. The technique is goal driven and can support decision making for configuration selection as required for stability and obstacle avoidance. Details of this technique and results are given.

Controlled synthesis of multi-arm star polyether-polycarbonate polyols based on propylene oxide and CO2.

PubMed

Hilf, Jeannette; Schulze, Patricia; Seiwert, Jan; Frey, Holger

2014-01-01

Multi-arm star copolymers based on a hyperbranched poly(propylene oxide) polyether-polyol (hbPPO) as a core and poly(propylene carbonate) (PPC) arms are synthesized in two steps from propylene oxide (PO), a small amount of glycidol and CO2 . The PPC arms are prepared via carbon dioxide (CO2 )/PO copolymerization, using hbPPO as a multifunctional macroinitiator and the (R,R)-(salcy)CoOBzF5 catalyst. Star copolymers with 14 and 28 PPC arms, respectively, and controlled molecular weights in the range of 2700-8800 g mol(-1) are prepared (Mw /Mn = 1.23-1.61). Thermal analysis reveals lowered glass transition temperatures in the range of -8 to 10 °C for the PPC star polymers compared with linear PPC, which is due to the influence of the flexible polyether core. Successful conversion of the terminal hydroxyl groups with phenylisocyanate demonstrates the potential of the polycarbonate polyols for polyurethane synthesis. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

KSC-06pd0484

NASA Image and Video Library

2006-03-14

KENNEDY SPACE CENTER, FLA. - Inside the Orbiter Processing Facility bay 3 at NASA's Kennedy Space Center, workers lower Discovery's robotic arm onto a flat bed in a work area. The arm was removed from Discovery's payload bay. The arm was removed due to damage found on the arm after it was accidentally bumped by a bridge bucket in the payload bay. Ultrasound inspections revealed a small crack, measuring 1.25 inches by 0.015 inch deep. The arm will be sent back to the vendor for repair. The bucket was being used by technicians cleaning the area and was in the process of being stowed. A bridge bucket is a personnel transport device that is suspended from an overhead bridge that moves back and forth above the shuttle's mid-body. It allows workers to access the payload bay area without walking or standing on the payload bay floor or on the fixed platforms. Space Shuttle Discovery is scheduled for launch on mission STS-121 during a launch planning window of July 1-19. Photo credit: NASA/Kim Shiflett

Companions for ``Nessie'' in the Milky Way's Skeleton

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2015-12-01

The recent discovery of a purported bone of the Milky Way, a dark cloud nicknamed Nessie, has provided us with new clues for mapping out the spiral structure of our galaxy. It turns out that Nessie may not be alone: a follow-up study has identified more bones, potentially making up a skeleton of the Milky Way that traces out the densest parts of its spiral arms.Inconvenient Vantage PointHow many spiral arms does the Milky Way have? Where are they located? What does the structure look like between the arms? It may seem surprising that these fundamental questions dont yet have clear answers. But because were stuck in the galaxys disk, were forced to piece together our understanding of the Milky Ways structure based primarily on measurements of position and radial velocity of structures within the galactic plane.The discovery of Nessie presents an intriguing new tool to identify the layout of the galaxy. Nessie is a very long, thin, infrared-dark filament that runs along the modeled position of the Scutum-Centaurus arm and is believed therefore to trace the structure of the arm. In a new study led by Catherine Zucker (University of Virginia, Harvard-Smithsonian Center for Astrophysics), the authors have searched for additional bones like Nessie, hoping to use them to map out the skeleton of the Milky Way.New Bones DiscoveredIn this map of radial velocity vs. galactic longitude, the bone candidates are indicated by the numbered points. The colored lines indicate the positions of two of the galactic spiral arms, according to various models. Click for a closer look! [Zucker et al. 2015]Zucker and collaborators began by using World Wide Telescope, a tool that facilitates visualization of multiple layers of data at a variety of scales, to search through Spitzer infrared data for additional structures like Nessie. Searching specifically along the predicted positions of galactic arms, they found 15 initial bone candidates.Next, the team obtained radial-velocity data for the candidates from five separate radio surveys. Five of the candidates did not have radial velocities consistent with the galactic rotation curve at the predicted positions of the nearby arms.Hope for a SkeletonThe authors used the remaining ten candidates to construct rough criteria for an object to be a Milky Way bone:Largely continuous mid-infrared extinction featureParallel to the galactic plane, to within 30Position within 20 pc of the galactic mid-planeRadial velocity within 10 km/s of the predicted velocity of a Milky Way armNo abrupt shifts in velocity within the extinction featureProjected aspect ratio of 50:1Of the ten candidates, six meet all the criteria and are thought to mark the location of significant spiral features in the galaxy. The authors believe that this method may be used to identify hundreds of Milky Way bones in the future. Combining this skeleton with other tracers of galactic structure will ultimately help us to piece together a more accurate map of our galaxy.BonusCheck out this video, produced by the authors using World Wide Telescope, that shows the locations of the newly discovered bone candidates within Spitzer images of the Milky Way galactic plane. [Credit: Zucker et al. 2015]Click here to view the video on YouTube.CitationCatherine Zucker et al 2015 ApJ 815 23. doi:10.1088/0004-637X/815/1/23

Chromosome 2 short arm translocations revealed by M-FISH analysis of neuroblastoma cell lines.

PubMed

Van Roy, N; Van Limbergen, H; Vandesompele, J; Van Gele, M; Poppe, B; Laureys, G; De Paepe, A; Speleman, F

2000-12-01

M-FISH analysis was performed on 18 neuroblastoma cell lines, which were previously studied with cytogenetic, standard FISH and CGH data. One of the most striking findings of this study was the detection of chromosome 2 short arm rearrangements in 61% of the investigated cell lines. These rearrangements resulted from translocations with various partner chromosomes. All translocations, except one were unbalanced, leading to the consistent gain of chromosome segment 2pter-p22. A cryptic balanced translocation t(2;4) was observed with a breakpoint located in the vicinity of MYCN in cell line NBL-S. Combination of M-FISH results together with cytogenetic, standard FISH and CGH data yielded the most comprehensive description of chromosome 2 short arm rearrangements, leading to a consistent gain of chromosome 2 short arm material. Copyright 2000 Wiley-Liss, Inc.

Axillary reverse mapping with indocyanine green or isosulfan blue demonstrate similar crossover rates to radiotracer identified sentinel nodes.

PubMed

Foster, Deshka; Choy, Nicole; Porter, Catherine; Ahmed, Shushmita; Wapnir, Irene

2018-03-01

Sentinel lymph node (SLN) resection is imperative for breast cancer staging. Axillary reverse mapping (ARM) can preserve arm draining nodes and lymphatics during surgery. ARM is generally performed with isosulfan blue (ISB), restricting its use for concurrent SLN biopsy. Indocyanine green (ICG) could serve as an alternative to ISB for ARM procedures. SLN mapping and biopsy was performed via periareolar injection of 99 technetium-sulfur colloid ( 99m TcSc, TSC). ISB and ICG were injected in the upper arm. Blue-stained lymphatics or nodes were visualized in the axilla; ICG was identified using the SPY Elite® system. Twenty-three patients underwent SLN biopsy with or without axillary node dissection and ARM procedures. Twenty of these patients had at least one hot node; 12 patients had SLNs that were only hot, 6 hot/blue/fluorescent, and 2 hot/fluorescent. Overall, crossover of ARM agents with SLNs occurred in 8 cases. Inspection of the axillary cavity after SLN biopsy revealed fluorescent lymphatics and nodes remaining in 14 and 7 patients, respectively. Blue lymphatics and blue nodes were detected in fewer cases. Nearly one-third of patients showed crossover between breast and arm draining nodes, which provides insight as to why some patients develop lymphedema symptoms after SLN biopsy. ICG and ISB identify similar numbers of SLNs. As such ICG could substitute for ISB in ARM procedures. © 2017 Wiley Periodicals, Inc.

Effects of age, sex and arm on the precision of arm position sense—left-arm superiority in healthy right-handers

PubMed Central

Schmidt, Lena; Depper, Lena; Kerkhoff, Georg

2013-01-01

Position sense is an important proprioceptive ability. Disorders of arm position sense (APS) often occur after unilateral stroke, and are associated with a negative functional outcome. In the present study we assessed horizontal APS by measuring angular deviations from a visually defined target separately for each arm in a large group of healthy subjects. We analyzed the accuracy and instability of horizontal APS as a function of age, sex and arm. Subjects were required to specify verbally the position of their unseen arm on a 0-90° circuit by comparing the current position with the target position indicated by a LED lamp, while the arm was passively moved by the examiner. Eighty-seven healthy subjects participated in the study, ranging from 20 to 77 years, subdivided into three age groups. The results revealed that APS was not a function of age or sex, but was significantly better in the non-dominant (left) arm in absolute errors (AE) but not in constant errors (CE) across all age groups of right-handed healthy subjects. This indicates a right-hemisphere superiority for left APS in right-handers and neatly fits to the more frequent and more severe left-sided body-related deficits in patients with unilateral stroke (i.e. impaired APS in left spatial neglect, somatoparaphrenia) or in individuals with abnormalities of the right cerebral hemisphere. These clinical issues will be discussed. PMID:24399962

Effects of age, sex and arm on the precision of arm position sense-left-arm superiority in healthy right-handers.

PubMed

Schmidt, Lena; Depper, Lena; Kerkhoff, Georg

2013-01-01

Position sense is an important proprioceptive ability. Disorders of arm position sense (APS) often occur after unilateral stroke, and are associated with a negative functional outcome. In the present study we assessed horizontal APS by measuring angular deviations from a visually defined target separately for each arm in a large group of healthy subjects. We analyzed the accuracy and instability of horizontal APS as a function of age, sex and arm. Subjects were required to specify verbally the position of their unseen arm on a 0-90° circuit by comparing the current position with the target position indicated by a LED lamp, while the arm was passively moved by the examiner. Eighty-seven healthy subjects participated in the study, ranging from 20 to 77 years, subdivided into three age groups. The results revealed that APS was not a function of age or sex, but was significantly better in the non-dominant (left) arm in absolute errors (AE) but not in constant errors (CE) across all age groups of right-handed healthy subjects. This indicates a right-hemisphere superiority for left APS in right-handers and neatly fits to the more frequent and more severe left-sided body-related deficits in patients with unilateral stroke (i.e. impaired APS in left spatial neglect, somatoparaphrenia) or in individuals with abnormalities of the right cerebral hemisphere. These clinical issues will be discussed.

A phase II study of lapatinib in recurrent/metastatic squamous cell carcinoma of the head and neck.

PubMed

de Souza, Jonas A; Davis, Darren W; Zhang, Yujian; Khattri, Arun; Seiwert, Tanguy Y; Aktolga, Serdal; Wong, Stuart J; Kozloff, Mark F; Nattam, Sreenivasa; Lingen, Mark W; Kunnavakkam, Rangesh; Stenson, Kerstin M; Blair, Elizabeth A; Bozeman, Jeffrey; Dancey, Janet E; Vokes, Everett E; Cohen, Ezra E W

2012-04-15

This study sought to determine the efficacy and safety profile of lapatinib in patients with recurrent/metastatic squamous cell carcinoma of the head and neck (SCCHN). This phase II multiinstitutional study enrolled patients with recurrent/metastatic SCCHN into two cohorts: those without (arm A) and those with (arm B) before exposure to an epidermal growth factor receptor (EGFR) inhibitor. All subjects were treated with lapatinib 1,500 mg daily. Primary endpoints were response rate (arm A) and progression-free survival (PFS; arm B). The biologic effects of lapatinib on tumor growth and survival pathways were assessed in paired tumor biopsies obtained before and after therapy. Forty-five patients were enrolled, 27 in arm A and 18 in arm B. Diarrhea was the most frequent toxicity occurring in 49% of patients. Seven patients experienced related grade 3 toxicity (3 fatigue, 2 hyponatremia, 1 vomiting, and 1 diarrhea). In an intent-to-treat analysis, no complete or partial responses were observed, and stable disease was the best response observed in 41% of arm A (median duration, 50 days, range, 34-159) and 17% of arm B subjects (median, 163 days, range, 135-195). Median PFS was 52 days in both arms. Median OS was 288 (95% CI, 62-374) and 155 (95% CI, 75-242) days for arms A and B, respectively. Correlative analyses revealed an absence of EGFR inhibition in tumor tissue. Lapatinib as a single agent in recurrent/metastatic SCCHN, although well tolerated, appears to be inactive in either EGFR inhibitor naive or refractory subjects. ©2012 AACR.

Galaxy Zoo and SPARCFIRE: constraints on spiral arm formation mechanisms from spiral arm number and pitch angles

NASA Astrophysics Data System (ADS)

Hart, Ross E.; Bamford, Steven P.; Hayes, Wayne B.; Cardamone, Carolin N.; Keel, William C.; Kruk, Sandor J.; Lintott, Chris J.; Masters, Karen L.; Simmons, Brooke D.; Smethurst, Rebecca J.

2017-12-01

In this paper, we study the morphological properties of spiral galaxies, including measurements of spiral arm number and pitch angle. Using Galaxy Zoo 2, a stellar mass-complete sample of 6222 SDSS spiral galaxies is selected. We use the machine vision algorithm SPARCFIRE to identify spiral arm features and measure their associated geometries. A support vector machine classifier is employed to identify reliable spiral features, with which we are able to estimate pitch angles for half of our sample. We use these machine measurements to calibrate visual estimates of arm tightness, and hence estimate pitch angles for our entire sample. The properties of spiral arms are compared with respect to various galaxy properties. The star formation properties of galaxies vary significantly with arm number, but not pitch angle. We find that galaxies hosting strong bars have spiral arms substantially (4°-6°) looser than unbarred galaxies. Accounting for this, spiral arms associated with many-armed structures are looser (by 2°) than those in two-armed galaxies. In contrast to this average trend, galaxies with greater bulge-to-total stellar mass ratios display both fewer and looser spiral arms. This effect is primarily driven by the galaxy disc, such that galaxies with more massive discs contain more spiral arms with tighter pitch angles. This implies that galaxy central mass concentration is not the dominant cause of pitch angle and arm number variations between galaxies, which in turn suggests that not all spiral arms are governed by classical density waves or modal theories.

The effects of training group exercise class instructors to adopt a motivationally adaptive communication style.

PubMed

Ntoumanis, N; Thøgersen-Ntoumani, C; Quested, E; Hancox, J

2017-09-01

Drawing from self-determination theory (Deci & Ryan, 2002), we developed and tested an intervention to train fitness instructors to adopt a motivationally adaptive communication style when interacting with exercisers. This was a parallel group, two-arm quasi-experimental design. Participants in the intervention arm were 29 indoor cycling instructors (n = 10 for the control arm) and 246 class members (n = 75 for the control arm). The intervention consisted of face-to-face workshops, education/information video clips, group discussions and activities, brainstorming, individual planning, and practical tasks in the cycling studio. Instructors and exercisers responded to validated questionnaires about instructors' use of motivational strategies and other motivation-related variables before the first workshop and at the end of the third and final workshop (4 months later). Time × arm interactions revealed no significant effects, possibly due to the large attrition of instructors and exercisers in the control arm. Within-group analyses in the intervention arm showed that exercisers' perceptions of instructor motivationally adaptive strategies, psychological need satisfaction, and intentions to remain in the class increased over time. Similarly, instructors in the intervention arm reported being less controlling and experiencing more need satisfaction over time. These results offer initial promising evidence for the positive impact of the training. © 2016 The Authors Scandinavian Journal of Medicine & Science in Sports Published by John Wiley & Sons Ltd.

SpArcFiRe: morphological selection effects due to reduced visibility of tightly winding arms in distant spiral galaxies

NASA Astrophysics Data System (ADS)

Peng, Tianrui Rae; Edward English, John; Silva, Pedro; Davis, Darren R.; Hayes, Wayne B.

2018-03-01

The Galaxy Zoo project has provided a plethora of valuable morphological data on a large number of galaxies from various surveys, and their team have identified and/or corrected for many biases. Here we study a new bias related to spiral arm pitch angles, which first requires selecting a sample of spiral galaxies that show observable structure. One obvious way is to select galaxies using a threshold in spirality, which we define as the fraction of Galaxy Zoo humans who have reported seeing spiral structure. Using such a threshold, we use the automated tool SpArcFiRe (SPiral ARC FInder and REporter) to measure spiral arm pitch angles. We observe that the mean pitch angle of spiral arms increases linearly with redshift for 0.05 < z < 0.085. We hypothesize that this is a selection effect due to tightly-wound arms becoming less visible as image quality degrades, leading to fewer such galaxies being above the spirality threshold as redshift increases. We corroborate this hypothesis by first artificially degrading images of nearby galaxies, and then using a machine learning algorithm trained on Galaxy Zoo data to provide a spirality for each artificially degraded image. We find that SpARcFiRe's ability to accurately measure pitch angles decreases as the image degrades, but that spirality decreases more quickly in galaxies with tightly wound arms, leading to the selection effect. This new bias means one must be careful in selecting a sample on which to measure spiral structure. Finally, we also include a sensitivity analysis of SpArcFiRe's internal parameters.

Tailored Behavioral Intervention Among Blacks With Metabolic Syndrome and Sleep Apnea: Results of the MetSO Trial.

PubMed

Jean-Louis, Girardin; Newsome, Valerie; Williams, Natasha J; Zizi, Ferdinand; Ravenell, Joseph; Ogedegbe, Gbenga

2017-01-01

To assess effectiveness of a culturally and linguistically tailored telephone-delivered intervention to increase adherence to physician-recommended evaluation and treatment of obstructive sleep apnea (OSA) among blacks. In a two-arm randomized controlled trial, we evaluated effectiveness of the tailored intervention among blacks with metabolic syndrome, relative to those in an attention control arm (n = 380; mean age = 58 ± 13; female = 71%). The intervention was designed to enhance adherence using culturally and linguistically tailored OSA health messages delivered by a trained health educator based on patients' readiness to change and unique barriers preventing desired behavior changes. Analysis showed 69.4% of the patients in the intervention arm attended initial consultation with a sleep specialist, compared to 36.7% in the control arm; 74.7% of those in the intervention arm and 66.7% in the control arm completed diagnostic evaluation; and 86.4% in the intervention arm and 88.9% in the control arm adhered to PAP treatment based on subjective report. Logistic regression analyses adjusting for sociodemographic factors indicated patients in the intervention arm were 3.17 times more likely to attend initial consultation, compared to those in the control arm. Adjusted models revealed no significant differences between the two arms regarding adherence to OSA evaluation or treatment. The intervention was successful in promoting importance of sleep consultation and evaluation of OSA among blacks, while there was no significant group difference in laboratory-based evaluation and treatment adherence rates. It seems that the fundamental barrier to OSA care in that population may be the importance of seeking OSA care. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

Impact of electronic coupling, symmetry, and planarization on one- and two-photon properties of triarylamines with one, two, or three diarylboryl acceptors.

PubMed

Makarov, Nikolay S; Mukhopadhyay, Sukrit; Yesudas, Kada; Brédas, Jean-Luc; Perry, Joseph W; Pron, Agnieszka; Kivala, Milan; Müllen, Klaus

2012-04-19

We have performed a study of the one- and two-photon absorption properties of a systematically varied series of triarylamino-compounds with one, two, or three attached diarylborane arms arranged in linear dipolar, bent dipolar, and octupolar geometries. Two-photon fluorescence excitation spectra were measured over a wide spectral range with femtosecond laser pulses. We found that on going from the single-arm to the two- and three-arm systems, the peak in two-photon absorption (2PA) cross-section is suppressed by factors of 3-11 for the lowest excitonic level associated with the electronic coupling of the arms, whereas it is enhanced by factors of 4-8 for the higher excitonic level. These results show that the coupling of arms redistributes the 2PA cross-section between the excitonic levels in a manner that strongly favors the higher-energy excitonic level. The experimental data on one- and two-photon cross-sections, ground- and excited-state transition dipole moments, and permanent dipole moment differences between the ground and the lowest excited states were compared to the results obtained from a simple Frenkel exciton model and from highly correlated quantum-chemical calculations. It has been found that planarization of the structure around the triarylamine moiety leads to a sizable increase in peak 2PA cross-section for the lowest excitonic level of the two-arm system, whereas for the three-arm system, the corresponding peak was weakened and shifted to lower energy. Our studies show the importance of the interarm coupling, number of arms, and structural planarity on both the enhancement and the suppression of two-photon cross-sections in multiarm molecules. © 2012 American Chemical Society

Geophysical setting of the Wabash Valley fault system

USGS Publications Warehouse

Hildenbrand, T.G.; Ravat, D.

1997-01-01

Interpretation of existing regional magnetic and gravity data and new local high-resolution aeromagnetic data provides new insights on the tectonic history and structural development of the Wabash Valley Fault System in Illinois and Indiana. Enhancement of short-wavelength magnetic anomalies reveal numerous NW- to NNE-trending ultramafic dikes and six intrusive complexes (including those at Hicks Dome and Omaha Dome). Inversion models indicate that the interpreted dikes are narrow (???3 m), lie at shallow depths (500 km long and generally >50 km wide) and with deep basins (locally >3 km thick), the ancestral Wabash Valley faults express, in comparison, minor tectonic structures and probably do not represent a failed rift arm. There is a lack of any obvious relation between the Wabash Valley Fault System and the epicenters of historic and prehistoric earthquakes. Five prehistoric earthquakes lie conspicuously near structures associated with the Commerce geophysical lineament, a NE-trending magnetic and gravity lineament lying oblique to the Wabash Valley Fault System and possibly extending over 600 km from NE Arkansas to central Indiana.

Structure of a Protein Phosphatase 2A Holoenzyme: Insights into B55-Mediated Tau Dephosphorylation

PubMed Central

Xu, Yanhui; Chen, Yu; Zhang, Ping; Jeffrey, Philip D.; Shi, Yigong

2009-01-01

Summary Protein phosphatase 2A (PP2A) regulates many essential aspects of cellular physiology. Members of the regulatory B/B55/PR55 family are thought to play a key role in the dephosphorylation of Tau, whose hyperphosphorylation contributes to Alzheimer's disease. The underlying mechanisms of the PP2A-Tau connection remain largely enigmatic. Here, we report the complete reconstitution of a Tau dephosphorylation assay and the crystal structure of a heterotrimeric PP2A holoenzyme involving the regulatory subunit Bα. We show that Bα specifically and markedly facilitates dephosphorylation of the phosphorylated Tau in our reconstituted assay. The Bα subunit comprises a seven-bladed β propeller, with an acidic, substrate-binding groove located in the center of the propeller. The β propeller latches onto the ridge of the PP2A scaffold subunit with the help of a protruding β hairpin arm. Structure-guided mutagenesis studies revealed the underpinnings of PP2A-mediated dephosphorylation of Tau. PMID:18922469

Structural basis for drug-induced allosteric changes to human β-cardiac myosin motor activity

PubMed Central

Winkelmann, Donald A.; Forgacs, Eva; Miller, Matthew T.; Stock, Ann M.

2015-01-01

Omecamtiv Mecarbil (OM) is a small molecule allosteric effector of cardiac myosin that is in clinical trials for treatment of systolic heart failure. A detailed kinetic analysis of cardiac myosin has shown that the drug accelerates phosphate release by shifting the equilibrium of the hydrolysis step towards products, leading to a faster transition from weak to strong actin-bound states. The structure of the human β-cardiac motor domain (cMD) with OM bound reveals a single OM-binding site nestled in a narrow cleft separating two domains of the human cMD where it interacts with the key residues that couple lever arm movement to the nucleotide state. In addition, OM induces allosteric changes in three strands of the β-sheet that provides the communication link between the actin-binding interface and the nucleotide pocket. The OM-binding interactions and allosteric changes form the structural basis for the kinetic and mechanical tuning of cardiac myosin. PMID:26246073

Structural Basis for Molecular Discrimination by a 3',3'-cGAMP Sensing Riboswitch

DOE PAGES

Ren, Aiming; Wang, Xin  C.; Kellenberger, Colleen  A.; ...

2015-04-07

Cyclic dinucleotides are second messengers that target the adaptor STING and stimulate the innate immune response in mammals. Besides protein receptors, there are bacterial riboswitches that selectively recognize cyclic dinucleotides. We recently discovered a natural riboswitch that targets 3',3'-cGAMP, which is distinguished from the endogenous mammalian signal 2',3'-cGAMP by its backbone connectivity. Here, we report on structures of the aptamer domain of the 3',3'-cGAMP riboswitch from Geobacter in the 3',3'-cGAMP and c-di-GMP bound states. The riboswitch adopts a tuning forklike architecture with a junctional ligand-binding pocket and different orientations of the arms are correlated with the identity of the boundmore » cyclic dinucleotide. Subsequent biochemical experiments revealed that specificity of ligand recognition can be affected by point mutations outside of the binding pocket, which has implications for both the assignment and reengineering of riboswitches in this structural class.« less

Is the spiral morphology of the Elias 2-27 circumstellar disc due to gravitational instability?

NASA Astrophysics Data System (ADS)

Hall, Cassandra; Rice, Ken; Dipierro, Giovanni; Forgan, Duncan; Harries, Tim; Alexander, Richard

2018-06-01

A recent Atacama Large Millimeter/submillimeter Array (ALMA) observation of the Elias 2-27 system revealed a two-armed structure extending out to ˜300 au in radius. The protostellar disc surrounding the central star is unusually massive, raising the possibility that the system is gravitationally unstable. Recent work has shown that the observed morphology of the system can be explained by disc self-gravity, so we examine the physical properties of the disc necessary to detect self-gravitating spiral waves. Using three-dimensional smoothed particle hydrodynamics, coupled with radiative transfer and synthetic ALMA imaging, we find that observable spiral structure can only be explained by self-gravity if the disc has a low opacity (and therefore efficient cooling), and is minimally supported by external irradiation. This corresponds to a very narrow region of parameter space, suggesting that, although it is possible for the spiral structure to be due to disc self-gravity, other explanations, such as an external perturbation, may be preferred.

Heterochromatin protein 1: don't judge the book by its cover!

PubMed

Hediger, Florence; Gasser, Susan M

2006-04-01

The name heterochromatin protein 1 (HP1) suggests that this small nuclear factor plays a role in forming heterochromatic domains. It was noticed years ago, however, that the distribution of HP1 on polytene chromosomes was not restricted to chromocenters or telomeres. HP1 was also found, reproducibly, along the euchromatic arms. A possible function in euchromatic gene regulation was postulated. Now, a large body of data has blurred the definition of HP1 as a structural component of heterochromatin, revealing its two-faced nature. Not only do HP1 isoforms have specific binding sites in both heterochromatic and euchromatic domains but they might also participate in the repression and activation of transcription in both compartments.

Relationship between cognitive insight and attenuated delusional symptoms in individuals with at-risk mental state.

PubMed

Uchida, Tomohiro; Matsumoto, Kazunori; Ito, Fumiaki; Ohmuro, Noriyuki; Miyakoshi, Tetsuo; Ueno, Takashi; Matsuoka, Hiroo

2014-06-30

Cognitive insight, defined as the ability to evaluate and correct one׳s own distorted beliefs and misinterpretations, is hypothesized to contribute to the development of psychotic symptoms. We investigated cognitive insight in individuals with at-risk mental state (ARMS), which is associated with a clinically high risk of psychosis. Sixty individuals with ARMS were compared with 200 healthy controls in terms of cognitive insight measured using the Beck Cognitive Insight Scale. We also investigated the relationship between cognitive insight and attenuated delusional symptoms. In addition, we examined differences in the cognitive insight of individuals with ARMS with or without near-threshold delusional symptoms and differences in the cognitive insight of individuals with ARMS with or without later transition to psychosis. The results showed that individuals with ARMS exhibited higher self-certainty than healthy controls, indicating impairments in cognitive insight in the former. More importantly, our results revealed that self-certainty was correlated with attenuated delusional symptoms and that individuals with ARMS who had near threshold delusional symptoms had higher self-certainty. These findings indicate that overconfidence in one׳s own beliefs or judgments might be related to the formation and maintenance of attenuated delusions in individuals with ARMS. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Journey to the center of the galaxy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chaisson, E.

1980-08-01

The solar system is a member of the Orion Arm of the Milky Way, far from the center of the Galaxy. This article takes the reader on a hypothetical journey from the solar system to the center of the Galaxy. Results from radio and infrared studies are used to suggest what such a journey might reveal. Traveling from the solar system toward the center, one crosses the Cygnus Arm, then the Sagittarius Arm, and then the so-called Three-kiloparsec Arm. The Arms contain a mixture of young stars as well as lots of gas and dust. Radio studies show that themore » Three-kiloparsec Arm is more like a ring than an arm. Inside this ring, is another ring composed of giant molecular clouds. Radio and infrared astronomers have discovered that the heart of the Galaxy is composed of matter in most perplexing states. There are three regions known within this innermost thousand light-years. First, there is a large zone of thin, hot ionized gas. Within this, there is a whirlpool of dense, warm matter. And further embedded, there seems to be a small supermassive object at the center. Possibly this object could be a blackhole. Researchers are continuing to examine, monitor, and model this mysterious region, the galactic nuclei. (SC)« less

Classifying and modelling spiral structures in hydrodynamic simulations of astrophysical discs

NASA Astrophysics Data System (ADS)

Forgan, D. H.; Ramón-Fox, F. G.; Bonnell, I. A.

2018-05-01

We demonstrate numerical techniques for automatic identification of individual spiral arms in hydrodynamic simulations of astrophysical discs. Building on our earlier work, which used tensor classification to identify regions that were `spiral-like', we can now obtain fits to spirals for individual arm elements. We show this process can even detect spirals in relatively flocculent spiral patterns, but the resulting fits to logarithmic `grand-design' spirals are less robust. Our methods not only permit the estimation of pitch angles, but also direct measurements of the spiral arm width and pattern speed. In principle, our techniques will allow the tracking of material as it passes through an arm. Our demonstration uses smoothed particle hydrodynamics simulations, but we stress that the method is suitable for any finite-element hydrodynamics system. We anticipate our techniques will be essential to studies of star formation in disc galaxies, and attempts to find the origin of recently observed spiral structure in protostellar discs.

The Relationship Between Structural Racism and Black-White Disparities in Fatal Police Shootings at the State Level.

PubMed

Mesic, Aldina; Franklin, Lydia; Cansever, Alev; Potter, Fiona; Sharma, Anika; Knopov, Anita; Siegel, Michael

2018-04-01

The objective of this study was to discern the relationship between state-level structural racism and Black-White disparities in police shootings of victims not known to be armed. Using a Poisson regression, we evaluated the effect of structural racism on differences between states in Black-White disparities in fatal police shootings involving victims not known to be armed during the period from January 1, 2013 through June 30, 2017. We created a state racism index, which was comprised of five dimensions: (1) residential segregation; and gaps in (2) incarceration rates; (3) educational attainment; (4) economic indicators; and (5) employment status. After controlling for numerous state-level factors and for the underlying rate of fatal shootings of black victims in each state, the state racism index was a significant predictor of the Black-White disparity in police shooting rates of victims not known to be armed (incidence rate ratio: 1.24; 95% confidence interval, 1.02-1.50). For every 10-point increase in the state racism index, the Black-White disparity ratio of police shooting rates of people not known to be armed increased by 24%. These findings suggest that structural racism is an important predictor of the Black-White disparity in rates of police shootings of unarmed victims across states. Copyright © 2018 National Medical Association. Published by Elsevier Inc. All rights reserved.

Control and applications of cooperating disparate robotic manipulators relevant to nuclear waste management

NASA Technical Reports Server (NTRS)

Lew, Jae Young; Book, Wayne J.

1991-01-01

Remote handling in nuclear waste management requires a robotic system with precise motion as well as a large workspace. The concept of a small arm mounted on the end of a large arm may satisfy such needs. However, the performance of such a serial configuration lacks payload capacity which is a crucial factor for handling a massive object. Also, this configuration induces more flexibility on the structure. To overcome these problems, the topology of bracing the tip of the small arm (not the large arm) and having an end effector in the middle of the chain is proposed in this paper. Also, control of these cooperating disparate manipulators is accomplished in computer simulations. Thus, this robotic system can have the accuracy of the small arm, and at the same time, it can have the payload capacity and large workspace of the large arm.

The Reliability and Factor Structure of the Job Activity Preference Questionnaire (JAPQ) and the Job Behavior Experience Questionnaire (JBEQ)

DTIC Science & Technology

1982-01-01

different bits of information to fly his plane, etc.) 35. Analyzing information (interpreting financial reports, determining why an automobile engine...involvin- hand and arm movements, as might be used in repairing automobiles , packaging products, etc.) I48. liand-arm steadiness (steady hand and arm...devices (pianos, typewriters, adding Rating Scale machines, etc.) 0 None 100. Highway or rail vehicles ( automobiles , trucks, 1 Very limited buses, trains

Telepresence control of a dual-arm dexterous robot

NASA Technical Reports Server (NTRS)

Li, Larry; Cox, Brian; Shelton, Susan; Diftler, Myron

1994-01-01

Telepresence is an approach to teleoperation that provides egocentric, intuitive interactions between an operator and a remote environment. This approach takes advantage of the natural cognitive and sensory-motor skills of an on-orbit crew and effectively transfers them to a slave robot. A dual-arm dexterous robot operating under telepresence control has been developed and is being evaluated. Preliminary evaluation revealed several important observations that suggest the directions of future enhancement.

Prodomain–growth factor swapping in the structure of pro-TGF-β1

PubMed Central

Xu, Shutong; Dong, Xianchi; Lu, Chafen; Springer, Timothy A.

2018-01-01

TGF-β is synthesized as a proprotein that dimerizes in the endoplasmic reticulum. After processing in the Golgi to cleave the N-terminal prodomain from the C-terminal growth factor (GF) domain in each monomer, pro-TGF-β is secreted and stored in latent complexes. It is unclear which prodomain and GF monomer are linked before proprotein convertase cleavage and how much conformational change occurs following cleavage. We have determined a structure of pro-TGF-β1 with the proprotein convertase cleavage site mutated to mimic the structure of the TGF-β1 proprotein. Structure, mutation, and model building demonstrate that the prodomain arm domain in one monomer is linked to the GF that interacts with the arm domain in the other monomer in the dimeric structure (i.e. the prodomain arm domain and GF domain in each monomer are swapped). Swapping has important implications for the mechanism of biosynthesis in the TGF-β family and is relevant to the mechanism for preferential formation of heterodimers over homodimers for some members of the TGF-β family. Our structure, together with two previous ones, also provides insights into which regions of the prodomain–GF complex are highly structurally conserved and which are perturbed by crystal lattice contacts. PMID:29109152

A randomized phase 2 study comparing two doses of delafloxacin with tigecycline in adults with complicated skin and skin-structure infections.

PubMed

O'Riordan, William; Mehra, Purvi; Manos, Paul; Kingsley, Jeff; Lawrence, Laura; Cammarata, Sue

2015-01-01

A randomized, double-blind, multicenter trial was done to compare two doses of delafloxacin with tigecycline in patients with various complicated skin and skin-structure infections (wound infections following surgery, trauma, burns, or animal/insect bites, abscesses, and cellulitis). Patients were randomized 1:1:1 to receive delafloxacin 300mg intravenous (IV) every 12h, delafloxacin 450mg IV every 12h, or tigecycline 100mg IV×1, followed by 50mg IV every 12h; randomization was stratified by infection type. Duration of therapy was 5-14 days. The primary efficacy analysis, performed on the clinically evaluable (CE) population at the test-of-cure (TOC) visit (14-21 days after the final dose of study drug), compared clinical response rates in the delafloxacin and tigecycline arms. Clinical response rates in the two delafloxacin arms were also compared. Among CE patients, clinical cure rates at TOC visit were similar in the delafloxacin and tigecycline arms (94.3%, 92.5%, and 91.2%, respectively in delafloxacin 300-mg, delafloxacin 450-mg, and tigecycline arms). Overall, the most frequent adverse events were nausea, vomiting, and diarrhea; the 300-mg delafloxacin arm was the best-tolerated regimen. Delafloxacin was similarly effective as tigecycline for a variety of complicated skin and skin-structure infections and was well tolerated. (Clinicaltrials.gov NCT 0719810). Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Structure of eukaryotic prefoldin and of its complexes with unfolded actin and the cytosolic chaperonin CCT

PubMed Central

Martín-Benito, Jaime; Boskovic, Jasminka; Gómez-Puertas, Paulino; Carrascosa, José L.; Simons, C.Torrey; Lewis, Sally A.; Bartolini, Francesca; Cowan, Nicholas J.; Valpuesta, José M.

2002-01-01

The biogenesis of the cytoskeletal proteins actin and tubulin involves interaction of nascent chains of each of the two proteins with the oligomeric protein prefoldin (PFD) and their subsequent transfer to the cytosolic chaperonin CCT (chaperonin containing TCP-1). Here we show by electron microscopy that eukaryotic PFD, which has a similar structure to its archaeal counterpart, interacts with unfolded actin along the tips of its projecting arms. In its PFD-bound state, actin seems to acquire a conformation similar to that adopted when it is bound to CCT. Three-dimensional reconstruction of the CCT:PFD complex based on cryoelectron microscopy reveals that PFD binds to each of the CCT rings in a unique conformation through two specific CCT subunits that are placed in a 1,4 arrangement. This defines the phasing of the CCT rings and suggests a handoff mechanism for PFD. PMID:12456645

Phoenix Dodo Trench

NASA Image and Video Library

2008-06-04

This image was taken by NASA's Phoenix Mars Lander's Robotic Arm Camera (RAC) on the ninth Martian day of the mission, or Sol 9 (June 3, 2008). The center of the image shows a trench informally called "Dodo" after the second dig. "Dodo" is located within the previously determined digging area, informally called "Knave of Hearts." The light square to the right of the trench is the Robotic Arm's Thermal and Electrical Conductivity Probe (TECP). The Robotic Arm has scraped to a bright surface which indicated the Arm has reached a solid structure underneath the surface, which has been seen in other images as well. http://photojournal.jpl.nasa.gov/catalog/PIA10763

Patterns of Transfer of Adaptation Among Body Segments

NASA Technical Reports Server (NTRS)

Seidler, R. D.; Bloomberg, J. J.; Stelmach, George E.

2000-01-01

Two experiments were conducted in order to determine the patterns of transfer of visuomotor adaptation between arm and head pointing. An altered gain of display of pointing movements was used to induce a conflict between visual and somatosensory representations. Two subject groups participated in Experiment One: group 1 adapted shoulder pointing movements, and group 2 adapted wrist pointing movements to a 0.5 gain of display. Following the adaptation regimen, subjects performed a transfer test in which the shoulder group performed wrist movements and the wrist group performed shoulder movements. The results demonstrated that both groups displayed typical adaptation curves, initially undershooting the target followed by a return to baseline performance. Transfer tests revealed that both groups had high transfer of the acquired adaptation to the other joint. Experiment Two followed a similar design except that group 1 adapted head pointing movements and group 2 adapted arm pointing movements. The arm adaptation had high transfer to head pointing while the head adaptation had very little transfer to arm pointing. These results imply that, while the arm segments may share a common target representation for goal-directed actions, individual but functionally dependent target representations may exist for the control of head and arm movements.

STS-112 Flight Day 4 Highlights

NASA Astrophysics Data System (ADS)

2002-10-01

On the fourth day of STS-112, its crew (Jeffrey Ashby, Commander; Pamela Melroy, Pilot; David Wolf, Mission Specialist; Piers Sellers, Mission Specialist; Sandra Magnus, Mission Specialist; Fyodor Yurchikhin, Mission Specialist) onboard Atlantis and the Expedition 5 crew (Valery Korzun, Commander; Peggy Whitson, Flight Engineer; Sergei Treschev, Flight Engineer) onboard the International Space Station (ISS) are seen preparing for the installation of the S1 truss structure. Inside the Destiny Laboratory Module, Korzun and other crewmembers are seen as they busily prepare for the work of the day. Sellers dons an oxygen mask and uses an exercise machine in order to purge the nitrogen from his bloodstream, in preparation for an extravehicular activity (EVA). Whitson uses the ISS's Canadarm 2 robotic arm to grapple the S1 truss and remove it from Atlantis' payload bay, with the assistance of Magnus. Using the robotic arm, Whitson slowly maneuvers the 15 ton truss structure into alignment with its attachment point on the starboard side of the S0 truss structure, where the carefully orchestrated mating procedures take place. There is video footage of the entire truss being rotated and positioned by the arm, and ammonia tank assembly on the structure is visible, with Earth in the background. Following the completion of the second stage capture, the robotic arm is ungrappled from truss. Sellers and Wolf are shown exiting the the Quest airlock hatch to begin their EVA. They are shown performing a variety of tasks on the now attached S1 truss structure, including work on the Crew Equipment Translation Cart (CETA), the S-band Antenna Assembly, and umbilical cables that provide power and remote operation capability to cameras. During their EVA, they are shown using a foot platform on the robotic arm. Significant portions of their activities are shown from the vantage of helmet mounted video cameras. The video closes with a final shot of the ISS and its new S1 truss.

Fabrication of supramolecular star-shaped amphiphilic copolymers for ROS-triggered drug release.

PubMed

Zuo, Cai; Peng, Jinlei; Cong, Yong; Dai, Xianyin; Zhang, Xiaolong; Zhao, Sijie; Zhang, Xianshuo; Ma, Liwei; Wang, Baoyan; Wei, Hua

2018-03-15

Star-shaped copolymers with branched structures can form unimolecular micelles with better stability than the micelles self-assembled from conventional linear copolymers. However, the synthesis of star-shaped copolymers with precisely controlled degree of branching (DB) suffers from complicated sequential polymerizations and multi-step purification procedures, as well as repeated optimizations of polymer compositions. The use of a supramolecular host-guest pair as the block junction would significantly simplify the preparation. Moreover, the star-shaped copolymer-based unimolecular micelle provides an elegant solution to the tradeoff between extracellular stability and intracellular high therapeutic efficacy if the association/dissociation of the supramolecular host-guest joint can be triggered by the biologically relevant stimuli. For this purpose, in this study, a panel of supramolecular star-shaped amphiphilic block copolymers with 9, 12, and 18 arms were designed and fabricated by host-guest complexations between the ring-opening polymerization (ROP)-synthesized star-shaped poly(ε-caprolactone) (PCL) with 3, 4, and 6 arms end-capped with ferrocene (Fc) (PCL-Fc) and the atom transfer radical polymerization (ATRP)-produced 3-arm poly(oligo ethylene glycol) methacrylates (POEGMA) with different degrees of polymerization (DPs) of 24, 30, 47 initiated by β-cyclodextrin (β-CD) (3Br-β-CD-POEGMA). The effect of DB and polymer composition on the self-assembled properties of the five star-shaped copolymers was investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM), and fluorescence spectrometery. Interestingly, the micelles self-assembled from 12-arm star-shaped copolymers exhibited greater stability than the 9- and 18-arm formulations. The potential of the resulting supramolecular star-shaped amphiphilic copolymers as drug carriers was evaluated by an in vitro drug release study, which confirmed the ROS-triggered accelerated drug release from the doxorubicin (DOX)-loaded supramolecular star-shaped micelles due to the oxidation-induced dissociation of β-CD/Fc pair and the consequent loss of the colloidal stability of the star-shaped micelles. Studies of the delivery efficacy by an in vitro cytotoxicity study further indicated that higher DBs and longer hydrophilic arm compromised the therapeutic efficacy of the DOX-loaded supramolecular star-shaped micelles, resulting in significantly reduced cytotoxicity, as measured by increased IC 50 value. Overall, our results revealed that the screening of hydrophilic block by DB and MW for an optimized star-shaped copolymer should balance the stability versus therapeutic efficacy tradeoff for a comprehensive consideration. Therefore, the 12-arm star-shaped copolymer with POEGMA 30 is the best formulation tested. Copyright © 2017 Elsevier Inc. All rights reserved.

Muscle mania: the quest for the perfect body.

PubMed

Hameed, Maira; Sahu, Ajay; Johnson, Maria B

2016-12-01

We describe the case of a young man with repeated hospital presentations for a variety of symptoms related to excessive bodybuilding and associated behaviours. He presented to our department (radiology) with right arm pain and loss of function. Ultrasound showed complete triceps rupture, rare in young patients and multiple cystic areas within the muscles of the arm. MRI revealed these to be multiple proteinaceous lesions within the muscle bellies and the possibility of self-innoculation was raised by the reporting radiologist. The patient subsequently admitted to injecting coconut oil to improve muscle contour lost secondary to injury. A review of his hospital presentations was then made and revealed further concerning practices performed by the patient to enhance his muscular appearance. 2016 BMJ Publishing Group Ltd.

Floating wind turbine system

NASA Technical Reports Server (NTRS)

Viterna, Larry A. (Inventor)

2009-01-01

A floating wind turbine system with a tower structure that includes at least one stability arm extending therefrom and that is anchored to the sea floor with a rotatable position retention device that facilitates deep water installations. Variable buoyancy for the wind turbine system is provided by buoyancy chambers that are integral to the tower itself as well as the stability arm. Pumps are included for adjusting the buoyancy as an aid in system transport, installation, repair and removal. The wind turbine rotor is located downwind of the tower structure to allow the wind turbine to follow the wind direction without an active yaw drive system. The support tower and stability arm structure is designed to balance tension in the tether with buoyancy, gravity and wind forces in such a way that the top of the support tower leans downwind, providing a large clearance between the support tower and the rotor blade tips. This large clearance facilitates the use of articulated rotor hubs to reduced damaging structural dynamic loads. Major components of the turbine can be assembled at the shore and transported to an offshore installation site.

Comparison of microtweezers based on three lateral thermal actuator configurations

NASA Astrophysics Data System (ADS)

Luo, J. K.; Flewitt, A. J.; Spearing, S. M.; Fleck, N. A.; Milne, W. I.

2005-06-01

Thermal actuator-based microtweezers with three different driving configurations have been designed, fabricated and characterized. Finite element analysis has been used to model the device performance. It was found that one configuration of microtweezer, based on two lateral bimorph thermal actuators, has a small displacement (tip opening of the tweezers) and a very limited operating power range. An alternative configuration consisting of two horizontal hot bars with separated beams as the arms can deliver a larger displacement with a much-extended operating power range. This structure can withstand a higher temperature due to the wider beams used, and has flexible arms for increased displacement. Microtweezers driven by a number of chevron structures in parallel have similar maximum displacements but at a cost of higher power consumption. The measured temperature of the devices confirms that the device with the chevron structure can deliver the largest displacement for a given working temperature, while the bimorph thermal actuator design has the highest operating temperature at the same power due to its thin hot arm, and is prone to structural failure.

[Hand-arm vibration syndrome in a nurse carrying out gypsum cutting operations].

PubMed

Speziale, Martina; Picchiotti, E

2009-01-01

A professional nurse, employed mainly on gypsum cutting operations, developed a hand-arm vibration syndrome with Raynaud's phenomenon, neurosensitive disorders and impairment of the bone and joints apparatus of the hand and arm. The nurse underwent diagnostic investigations (cold test, X-ray of the upper limbs, blood tests); also the vibration levels transmitted from instrument were measured and the exposure times were established. Clinical investigations showed the presence of a hand-arm vibration syndrome with secondary Raynaud's phenomenon and environmental surveys revealed very high vibration levels, such as could be associated with the disease with a causal relationship. In the literature no reports exist of the vibration syndrome being associated with health care workers in orthopaedic departments. The case described in this study occurred because of peculiar organisational factors that most likely have never occurred in other hospitals or orthopaedic departments.

Extensive homology of chicken macrochromosomes in the karyotypes of Trachemys scripta elegans and Crocodylus niloticus revealed by chromosome painting despite long divergence times.

PubMed

Kasai, F; O'Brien, P C M; Martin, S; Ferguson-Smith, M A

2012-01-01

We report extensive chromosome homology revealed by chromosome painting between chicken (Gallus gallus domesticus, GGA, 2n = 78) macrochromosomes (representing 70% of the chicken genome) and the chromosomes of a turtle, the red-eared slider (Trachemys scripta elegans, TSC, 2n = 50), and the Nile crocodile (Crocodylus niloticus, CNI, 2n = 32). Our data show that GGA1-8 arms seem to be conserved in the arms of TSC chromosomes, GGA1-2 arms are separated and homologous to CNI1p, 3q, 4q and 5q. In addition to GGAZ homologues in our previous study, large-scale GGA autosome syntenies have been conserved in turtle and crocodile despite hundreds of millions of years divergence time. Based on phylogenetic hypotheses that crocodiles diverged after the divergence of birds and turtles, our results in CNI suggest that GGA1-2 and TSC1-2 represent the ancestral state and that chromosome fissions followed by fusions have been the mechanisms responsible for the reduction of chromosome number in crocodiles. Copyright © 2012 S. Karger AG, Basel.

On-chip beamsplitter operation on single photons from quasi-resonantly excited quantum dots embedded in GaAs rib waveguides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rengstl, U.; Schwartz, M.; Herzog, T.

2015-07-13

We present an on-chip beamsplitter operating on a single-photon level by means of a quasi-resonantly driven InGaAs/GaAs quantum dot. The single photons are guided by rib waveguides and split into two arms by an evanescent field coupler. Although the waveguides themselves support the fundamental TE and TM modes, the measured degree of polarization (∼90%) reveals the main excitation and propagation of the TE mode. We observe the preserved single-photon nature of a quasi-resonantly excited quantum dot by performing a cross-correlation measurement on the two output arms of the beamsplitter. Additionally, the same quantum dot is investigated under resonant excitation, wheremore » the same splitting ratio is observed. An autocorrelation measurement with an off-chip beamsplitter on a single output arm reveal the single-photon nature after evanescent coupling inside the on-chip splitter. Due to their robustness, adjustable splitting ratio, and their easy implementation, rib waveguide beamsplitters with embedded quantum dots provide a promising step towards fully integrated quantum circuits.« less

The observed spiral structure of the Milky Way

NASA Astrophysics Data System (ADS)

Hou, L. G.; Han, J. L.

2014-09-01

Context. The spiral structure of the Milky Way is not yet well determined. The keys to understanding this structure are to increase the number of reliable spiral tracers and to determine their distances as accurately as possible. HII regions, giant molecular clouds (GMCs), and 6.7 GHz methanol masers are closely related to high mass star formation, and hence they are excellent spiral tracers. The distances for many of them have been determined in the literature with trigonometric, photometric, and/or kinematic methods. Aims: We update the catalogs of Galactic HII regions, GMCs, and 6.7 GHz methanol masers, and then outline the spiral structure of the Milky Way. Methods: We collected data for more than 2500 known HII regions, 1300 GMCs, and 900 6.7 GHz methanol masers. If the photometric or trigonometric distance was not yet available, we determined the kinematic distance using a Galaxy rotation curve with the current IAU standard, R0 = 8.5 kpc and Θ0 = 220 km s-1, and the most recent updated values of R0 = 8.3 kpc and Θ0 = 239 km s-1, after velocities of tracers are modified with the adopted solar motions. With the weight factors based on the excitation parameters of HII regions or the masses of GMCs, we get the distributions of these spiral tracers. Results: The distribution of tracers shows at least four segments of arms in the first Galactic quadrant, and three segments in the fourth quadrant. The Perseus Arm and the Local Arm are also delineated by many bright HII regions. The arm segments traced by massive star forming regions and GMCs are able to match the HI arms in the outer Galaxy. We found that the models of three-arm and four-arm logarithmic spirals are able to connect most spiral tracers. A model of polynomial-logarithmic spirals is also proposed, which not only delineates the tracer distribution, but also matches the observed tangential directions. Appendix A is available in electronic form at http://www.aanda.orgFull Tables A.1-A.3 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/569/A125 and also at the authors' webpage: http://zmtt.bao.ac.cn/milkyway/

Nonparetic arm force does not overinhibit the paretic arm in chronic poststroke hemiparesis.

PubMed

Dimyan, Michael A; Perez, Monica A; Auh, Sungyoung; Tarula, Erick; Wilson, Matthew; Cohen, Leonardo G

2014-05-01

To determine whether nonparetic arm force overinhibits the paretic arm in patients with chronic unilateral poststroke hemiparesis. Case-control neurophysiological and behavioral study of patients with chronic stroke. Research institution. Eighty-six referred patients were screened to enroll 9 participants (N=9) with a >6 month history of 1 unilateral ischemic infarct that resulted in arm hemiparesis with residual ability to produce 1Nm of wrist flexion torque and without contraindication to transcranial magnetic stimulation. Eight age- and handedness-matched healthy volunteers without neurologic diagnosis were studied for comparison. Not applicable. Change in interhemispheric inhibition targeting the ipsilesional primary motor cortex (M1) during nonparetic arm force. We hypothesized that interhemispheric inhibition would increase more in healthy controls than in patients with hemiparesis. Healthy age-matched controls had significantly greater increases in inhibition from their active to resting M1 than patients with stroke from their active contralesional to resting ipsilesional M1 in the same scenario (20%±7% vs -1%±4%, F1,12=6.61, P=.025). Patients with greater increases in contralesional to ipsilesional inhibition were better performers on the 9-hole peg test of paretic arm function. Our findings reveal that producing force with the nonparetic arm does not necessarily overinhibit the paretic arm. Though our study is limited in generalizability by the small sample size, we found that greater active contralesional to resting ipsilesional M1 inhibition was related with better recovery in this subset of patients with chronic poststroke. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Enzymatic Synthesis of Self-assembled Dicer Substrate RNA Nanostructures for Programmable Gene Silencing.

PubMed

Jang, Bora; Kim, Boyoung; Kim, Hyunsook; Kwon, Hyokyoung; Kim, Minjeong; Seo, Yunmi; Colas, Marion; Jeong, Hansaem; Jeong, Eun Hye; Lee, Kyuri; Lee, Hyukjin

2018-06-08

Enzymatic synthesis of RNA nanostructures is achieved by isothermal rolling circle transcription (RCT). Each arm of RNA nanostructures provides a functional role of Dicer substrate RNA inducing sequence specific RNA interference (RNAi). Three different RNAi sequences (GFP, RFP, and BFP) are incorporated within the three-arm junction RNA nanostructures (Y-RNA). The template and helper DNA strands are designed for the large-scale in vitro synthesis of RNA strands to prepare self-assembled Y-RNA. Interestingly, Dicer processing of Y-RNA is highly influenced by its physical structure and different gene silencing activity is achieved depending on its arm length and overhang. In addition, enzymatic synthesis allows the preparation of various Y-RNA structures using a single DNA template offering on demand regulation of multiple target genes.

Self-perpetuating Spiral Arms in Disk Galaxies

NASA Astrophysics Data System (ADS)

D'Onghia, Elena; Vogelsberger, Mark; Hernquist, Lars

2013-03-01

The causes of spiral structure in galaxies remain uncertain. Leaving aside the grand bisymmetric spirals with their own well-known complications, here we consider the possibility that multi-armed spiral features originate from density inhomogeneities orbiting within disks. Using high-resolution N-body simulations, we follow the motions of stars under the influence of gravity, and show that mass concentrations with properties similar to those of giant molecular clouds can induce the development of spiral arms through a process termed swing amplification. However, unlike in earlier work, we demonstrate that the eventual response of the disk can be highly non-linear, significantly modifying the formation and longevity of the resulting patterns. Contrary to expectations, ragged spiral structures can thus survive at least in a statistical sense long after the original perturbing influence has been removed.

Telerobotic research at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Sliwa, Nancy E.

1987-01-01

An overview of Automation Technology Branch facilities and research is presented. Manipulator research includes dual-arm coordination studies, space manipulator dynamics, end-effector controller development, automatic space structure assembly, and the development of a dual-arm master-slave telerobotic manipulator system. Sensor research includes gravity-compensated force control, real-time monovision techniques, and laser ranging. Artificial intelligence techniques are being explored for supervisory task control, collision avoidance, and connectionist system architectures. A high-fidelity dynamic simulation of robotic systems, ROBSIM, is being supported and extended. Cooperative efforts with Oak Ridge National Laboratory have verified the ability of teleoperators to perform complex structural assembly tasks, and have resulted in the definition of a new dual-arm master-slave telerobotic manipulator. A bibliography of research results and a list of technical contacts are included.

New Exoskeleton Arm Concept Design And Actuation For Haptic Interaction With Virtual Objects

NASA Astrophysics Data System (ADS)

Chakarov, D.; Veneva, I.; Tsveov, M.; Tiankov, T.

2014-12-01

In the work presented in this paper the conceptual design and actuation of one new exoskeleton of the upper limb is presented. The device is designed for application where both motion tracking and force feedback are required, such as human interaction with virtual environment or rehabilitation tasks. The choice is presented of mechanical structure kinematical equivalent to the structure of the human arm. An actuation system is selected based on braided pneumatic muscle actuators. Antagonistic drive system for each joint is shown, using pulley and cable transmissions. Force/displacement diagrams are presented of two antagonistic acting muscles. Kinematics and dynamic estimations are performed of the system exoskeleton and upper limb. Selected parameters ensure in the antagonistic scheme joint torque regulation and human arm range of motion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

McKenzie, Kirk; Spero, Robert E.; Shaddock, Daniel A.

For the Laser Interferometer Space Antenna (LISA) to reach its design sensitivity, the coupling of the free-running laser frequency noise to the signal readout must be reduced by more than 14 orders of magnitude. One technique employed to reduce the laser frequency noise will be arm locking, where the laser frequency is locked to the LISA arm length. In this paper we detail an implementation of arm locking. We investigate orbital effects (changing arm lengths and Doppler frequencies), the impact of errors in the Doppler knowledge that can cause pulling of the laser frequency, and the noise limit of armmore » locking. Laser frequency pulling is examined in two regimes: at lock acquisition and in steady state. The noise performance of arm locking is calculated with the inclusion of the dominant expected noise sources: ultrastable oscillator (clock) noise, spacecraft motion, and shot noise. We find that clock noise and spacecraft motion limit the performance of dual arm locking in the LISA science band. Studying these issues reveals that although dual arm locking [A. Sutton and D. A. Shaddock, Phys. Rev. D 78, 082001 (2008)] has advantages over single (or common) arm locking in terms of allowing high gain, it has disadvantages in both laser frequency pulling and noise performance. We address this by proposing a modification to the dual arm-locking sensor, a hybrid of common and dual arm-locking sensors. This modified dual arm-locking sensor has the laser frequency pulling characteristics and low-frequency noise coupling of common arm locking, but retains the control system advantages of dual arm locking. We present a detailed design of an arm-locking controller and perform an analysis of the expected performance when used with and without laser prestabilization. We observe that the sensor phase changes beneficially near unity-gain frequencies of the arm-locking controller, allowing a factor of 10 more gain than previously believed, without degrading stability. With a time-delay error of 3 ns (equivalent of 1 m interspacecraft ranging error), time-delay interferometry (TDI) is capable of suppressing 300 Hz/{radical}(Hz) of laser frequency noise to the required level. We show that if no interspacecraft laser links fail, arm locking alone surpasses this noise performance for the entire mission. If one interspacecraft laser link fails, arm locking alone will achieve this performance for all but approximately 1 h per year, when the arm length mismatch of the two remaining arms passes through zero. Therefore, the LISA sensitivity can be realized with arm locking and time-delay interferometry only, without any form of prestabilization.« less

Extreme Asymmetry in the Polarized Disk of V1247 Orionis

NASA Technical Reports Server (NTRS)

Ohta, Yurina; Fukagawa, Misato; Sitko, Michael; Muto, Takayuki; Kraus, Stefan; Grady, Carol A.; Wisniewski, John A.; Swearingen, Jeremy R.; Shibai, Hiroshi; McElwain, Michael W.

2016-01-01

We present the first near-infrared scattered-light detection of the transitional disk around V1247 Ori, which was obtained using high-resolution polarimetric differential imaging observations with Subaru/HiCIAO. Our imaging in the H band reveals the disk morphology at separations of approx.0.14-0.86 (54-330 au) from the central star. The polarized intensity image shows a remarkable arc-like structure toward the southeast of the star, whereas the fainter northwest region does not exhibit any notable features. The shape of the arm is consistent with an arc of 0.28 +/- 0.09 in radius (108 au from the star), although the possibility of a spiral arm with a small pitch angle cannot be excluded. V1247 Ori features an exceptionally large azimuthal contrast in scattered, polarized light; the radial peak of the southeastern arc is about three times brighter than the northwestern disk measured at the same distance from the star. Combined with the previous indication of an inhomogeneous density distribution in the gap at 46 au, the notable asymmetry in the outer disk suggests the presence of unseen companions and/or planet-forming processes ongoing in the arc.

Spiral Structure and Differential Dust Size Distribution in the LkH(alpha) 330 Disk

NASA Technical Reports Server (NTRS)

Akiyama, Eiji; Hashimoto, Jun; Liu, Hauyu Baobabu; Li, Jennifer I-hsiu; Bonnefoy, Michael; Dong, Ruobing; Hasegawa, Yasuhiro; Henning, Thomas; Sitko, Michael L.; Janson, Markus;

Please mind the gap - Visual census and cryptic biodiversity assessment at central Red Sea coral reefs.

PubMed

Pearman, John K; Anlauf, Holger; Irigoien, Xabier; Carvalho, Susana

2016-07-01

Coral reefs harbor the most diverse assemblages in the ocean, however, a large proportion of the diversity is cryptic and, therefore, undetected by standard visual census techniques. Cryptic and exposed communities differ considerably in species composition and ecological function. This study compares three different coral reef assessment protocols: i) visual benthic reef surveys: ii) visual census of Autonomous Reef Monitoring Structures (ARMS) plates; and iii) metabarcoding techniques of the ARMS (including sessile, 106-500 μm and 500-2000 μm size fractions), that target the cryptic and exposed communities of three reefs in the central Red Sea. Visual census showed a dominance of Cnidaria (Anthozoa) and Rhodophyta on the reef substrate, while Porifera, Bryozoa and Rhodophyta were the most abundant groups on the ARMS plates. Metabarcoding, targeting the 18S rRNA gene, significantly increased estimates of the species diversity (p < 0.001); revealing that Annelida were generally the dominant phyla (in terms of reads) of all fractions and reefs. Furthermore, metabarcoding detected microbial eukaryotic groups such as Syndiniophyceae, Mamiellophyceae and Bacillariophyceae as relevant components of the sessile fraction. ANOSIM analysis showed that the three reef sites showed no differences based on the visual census data. Metabarcoding showed a higher sensitivity for identifying differences between reef communities at smaller geographic scales than standard visual census techniques as significant differences in the assemblages were observed amongst the reefs. Comparison of the techniques showed no similar patterns for the visual techniques while the metabarcoding of the ARMS showed similar patterns amongst fractions. Establishing ARMS as a standard tool in reef monitoring will not only advance our understanding of local processes and ecological community response to environmental changes, as different faunal components will provide complementary information but also improve the estimates of biodiversity in coral reef benthic communities. This study lays the foundations for further studies looking at integrating traditional reef survey methodologies with complementary approaches, such as metabarcoding, which investigate other components of the reef community. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

The Relationship of Throwing Arm Mechanics and Elbow Varus Torque: Within-Subject Variation for Professional Baseball Pitchers Across 82,000 Throws.

PubMed

Camp, Christopher L; Tubbs, Travis G; Fleisig, Glenn S; Dines, Joshua S; Dines, David M; Altchek, David W; Dowling, Brittany

2017-11-01

Likely due to the high level of strain exerted across the elbow during the throwing motion, elbow injuries are on the rise in baseball. To identify at-risk athletes and guide postinjury return-to-throw programs, a better understanding of the variables that influence elbow varus torque is desired. To describe the within-subject relationship between elbow varus torque and arm slot and arm rotation in professional baseball pitchers. Descriptive laboratory study. A total of 81 professional pitchers performed 82,000 throws while wearing a motusBASEBALL sensor and sleeve. These throws represented a combination of throw types, such as warm-up/catch, structured long-toss, bullpen throwing from a mound, and live game activity. Variables recorded for each throw included arm slot (angle of the forearm relative to the ground at ball release), arm speed (maximal rotational velocity of the forearm), arm rotation (maximal external rotation of the throwing arm relative to the ground), and elbow varus torque. Linear mixed-effects models and likelihood ratio tests were used to estimate the relationship between elbow varus torque and arm slot, arm speed, and arm rotation within individual pitchers. All 3 metrics-arm slot (χ 2 = 428, P < .001), arm speed (χ 2 = 57,683, P < .001), and arm rotation (χ 2 = 1392, P < .001)-were found to have a significant relationship with elbow varus torque. Within individual athletes, a 1-N.m increase in elbow varus torque was associated with a 13° decrease in arm slot, a 116 deg/s increase in arm speed, and an 8° increase in arm rotation. Elbow varus torque increased significantly as pitchers increased their arm rotation during the arm cocking phase, increased the rotational velocity of their arm during the arm acceleration phase of throwing, and decreased arm slot at ball release. Thus, shoulder flexibility, arm speed, and elbow varus torque (and likely injury risk) are interrelated and should be considered collectively when treating pitchers. It is well established that elbow varus torque is related to ulnar collateral ligament injuries in overhead throwers. This study describes the relationship of arm slot, arm speed, and arm rotation to elbow varus torque in an attempt to identify modifiable risk factors for injury.

The influence of polymer architecture on the assembly of poly(ethylene oxide) grafted C60 fullerene clusters in aqueous solution: a molecular dynamics simulation study.

PubMed

Hooper, Justin B; Bedrov, Dmitry; Smith, Grant D

2009-03-28

The effect of polymer architecture on the aggregation behavior of C60 fullerenes tethered with a single chain of poly(ethylene oxide) (PEO) in aqueous solution has been investigated using coarse-grained, implicit solvent molecular dynamics simulations. The PEO-grafted fullerenes were comprised of a single tether of 60 repeat units represented as a linear polymer, a three-arm star (20 repeat units/arm) or a six-arm star (10 repeat units/arm). Additionally, the influence of arm length on self-assembly of the PEO-fullerene conjugates was investigated for the three-arm stars. Self-assembly is driven by favorable fullerene-fullerene and fullerene-PEO interactions. Our simulations reveal that it should be possible to control the size and geometry of the self-assembled fullerene aggregates in water through variation of PEO architecture and PEO molecular weight. We found that aggregate size and shape could be understood qualitatively in terms of the packing parameter concept that has been employed for diblock polymer and surfactant self-assembly. Higher molecular weight PEO (longer arms) and more compact PEO (more arms for the same molecular weight) resulted in greater steric repulsion between fullerenes, engendering greater aggregate surface curvature and hence the formation of smaller, more spherically shaped aggregates. Finally, weak attractive interactions between PEO and the fullerenes were found to play an important role in determining aggregate shape, size and the dynamics of self-assembly.

Consecutive learning of opposing unimanual motor tasks using the right arm followed by the left arm causes intermanual interference

PubMed Central

Thürer, Benjamin; Stein, Thorsten

2017-01-01

Intermanual transfer (motor memory generalization across arms) and motor memory interference (impairment of retest performance in consecutive motor learning) are well-investigated motor learning phenomena. However, the interplay of these phenomena remains elusive, i.e., whether intermanual interference occurs when two unimanual tasks are consecutively learned using different arms. Here, we examine intermanual interference when subjects consecutively adapt their right and left arm movements to novel dynamics. We considered two force field tasks A and B which were of the same structure but mirrored orientation (B = -A). The first test group (ABA-group) consecutively learned task A using their right arm and task B using their left arm before being retested for task A with their right arm. Another test group (AAA-group) learned only task A in the same right-left-right arm schedule. Control subjects learned task A using their right arm without intermediate left arm learning. All groups were able to adapt their right arm movements to force field A and both test groups showed significant intermanual transfer of this initial learning to the contralateral left arm of 21.9% (ABA-group) and 27.6% (AAA-group). Consecutively, both test groups adapted their left arm movements to force field B (ABA-group) or force field A (AAA-group). For the ABA-group, left arm learning caused significant intermanual interference of the initially learned right arm task (68.3% performance decrease). The performance decrease of the AAA-group (10.2%) did not differ from controls (15.5%). These findings suggest that motor control and learning of right and left arm movements involve partly similar neural networks or underlie a vital interhemispheric connectivity. Moreover, our results suggest a preferred internal task representation in extrinsic Cartesian-based coordinates rather than in intrinsic joint-based coordinates because interference was absent when learning was performed in extrinsically equivalent fashion (AAA-group) but interference occurred when learning was performed in intrinsically equivalent fashion (ABA-group). PMID:28459833

Consecutive learning of opposing unimanual motor tasks using the right arm followed by the left arm causes intermanual interference.

PubMed

Stockinger, Christian; Thürer, Benjamin; Stein, Thorsten

2017-01-01

Intermanual transfer (motor memory generalization across arms) and motor memory interference (impairment of retest performance in consecutive motor learning) are well-investigated motor learning phenomena. However, the interplay of these phenomena remains elusive, i.e., whether intermanual interference occurs when two unimanual tasks are consecutively learned using different arms. Here, we examine intermanual interference when subjects consecutively adapt their right and left arm movements to novel dynamics. We considered two force field tasks A and B which were of the same structure but mirrored orientation (B = -A). The first test group (ABA-group) consecutively learned task A using their right arm and task B using their left arm before being retested for task A with their right arm. Another test group (AAA-group) learned only task A in the same right-left-right arm schedule. Control subjects learned task A using their right arm without intermediate left arm learning. All groups were able to adapt their right arm movements to force field A and both test groups showed significant intermanual transfer of this initial learning to the contralateral left arm of 21.9% (ABA-group) and 27.6% (AAA-group). Consecutively, both test groups adapted their left arm movements to force field B (ABA-group) or force field A (AAA-group). For the ABA-group, left arm learning caused significant intermanual interference of the initially learned right arm task (68.3% performance decrease). The performance decrease of the AAA-group (10.2%) did not differ from controls (15.5%). These findings suggest that motor control and learning of right and left arm movements involve partly similar neural networks or underlie a vital interhemispheric connectivity. Moreover, our results suggest a preferred internal task representation in extrinsic Cartesian-based coordinates rather than in intrinsic joint-based coordinates because interference was absent when learning was performed in extrinsically equivalent fashion (AAA-group) but interference occurred when learning was performed in intrinsically equivalent fashion (ABA-group).

Integration of Visual and Proprioceptive Limb Position Information in Human Posterior Parietal, Premotor, and Extrastriate Cortex.

PubMed

Limanowski, Jakub; Blankenburg, Felix

2016-03-02

The brain constructs a flexible representation of the body from multisensory information. Previous work on monkeys suggests that the posterior parietal cortex (PPC) and ventral premotor cortex (PMv) represent the position of the upper limbs based on visual and proprioceptive information. Human experiments on the rubber hand illusion implicate similar regions, but since such experiments rely on additional visuo-tactile interactions, they cannot isolate visuo-proprioceptive integration. Here, we independently manipulated the position (palm or back facing) of passive human participants' unseen arm and of a photorealistic virtual 3D arm. Functional magnetic resonance imaging (fMRI) revealed that matching visual and proprioceptive information about arm position engaged the PPC, PMv, and the body-selective extrastriate body area (EBA); activity in the PMv moreover reflected interindividual differences in congruent arm ownership. Further, the PPC, PMv, and EBA increased their coupling with the primary visual cortex during congruent visuo-proprioceptive position information. These results suggest that human PPC, PMv, and EBA evaluate visual and proprioceptive position information and, under sufficient cross-modal congruence, integrate it into a multisensory representation of the upper limb in space. The position of our limbs in space constantly changes, yet the brain manages to represent limb position accurately by combining information from vision and proprioception. Electrophysiological recordings in monkeys have revealed neurons in the posterior parietal and premotor cortices that seem to implement and update such a multisensory limb representation, but this has been difficult to demonstrate in humans. Our fMRI experiment shows that human posterior parietal, premotor, and body-selective visual brain areas respond preferentially to a virtual arm seen in a position corresponding to one's unseen hidden arm, while increasing their communication with regions conveying visual information. These brain areas thus likely integrate visual and proprioceptive information into a flexible multisensory body representation. Copyright © 2016 the authors 0270-6474/16/362582-08$15.00/0.

Synthesis and structural studies of two pyridine-armed reinforced cyclen chelators and their transition metal complexes.

PubMed

Wilson, Kevin R; Cannon-Smith, Desiray J; Burke, Benjamin P; Birdsong, Orry C; Archibald, Stephen J; Hubin, Timothy J

2016-08-16

Two novel pyridine pendant-armed macrocycles structurally reinforced by an ethyl bridge, either between adjacent nitrogens (for side-bridged) or non-adjacent nitrogens (for cross-bridged), have been synthesized and complexed with a range of transition metal ions (Co 2+ , Ni 2+ , Cu 2+ and Zn 2+ ). X-ray crystal structures of selected cross-bridged complexes were obtained which showed the characteristic cis-V configuration with potential labile cis binding sites. The complexes have been characterized by their electronic spectra and magnetic moments, which show the expected high spin divalent metal complex in most cases. Exceptions are the nickel side-bridged complex, which shows a mixture of high-spin and low spin, and the cobalt cross-bridged complex which has oxidized to cobalt(III). Cyclic voltammetry in acetonitrile was carried out to assess the potential future use of these complexes in oxidation catalysis. Selected complexes offer significant catalytic potential enhanced by the addition of the pyridyl arm to a reinforced cyclen backbone.

Adaptive control of dual-arm robots

NASA Technical Reports Server (NTRS)

Seraji, H.

1987-01-01

Three strategies for adaptive control of cooperative dual-arm robots are described. In the position-position control strategy, the adaptive controllers ensure that the end-effector positions of both arms track desired trajectories in Cartesian space despite unknown time-varying interaction forces exerted through the load. In the position-hybrid control strategy, the adaptive controller of one arm controls end-effector motions in the free directions and applied forces in the constraint directions, while the adaptive controller of the other arm ensures that the end-effector tracks desired position trajectories. In the hybrid-hybrid control strategy, the adaptive controllers ensure that both end-effectors track reference position trajectories while simultaneously applying desired forces on the load. In all three control strategies, the cross-coupling effects between the arms are treated as disturbances which are rejected by the adaptive controllers while following desired commands in a common frame of reference. The adaptive controllers do not require the complex mathematical model of the arm dynamics or any knowledge of the arm dynamic parameters or the load parameters such as mass and stiffness. The controllers have simple structures and are computationally fast for on-line implementation with high sampling rates.

Search For Star Cluster Age Gradients Across Spiral Arms of Three LEGUS Disk Galaxies

NASA Astrophysics Data System (ADS)

Shabani, F.; Grebel, E. K.; Pasquali, A.; D'Onghia, E.; Gallagher, J. S.; Adamo, A.; Messa, M.; Elmegreen, B. G.; Dobbs, C.; Gouliermis, D. A.; Calzetti, D.; Grasha, K.; Elmegreen, D. M.; Cignoni, M.; Dale, D. A.; Aloisi, A.; Smith, L. J.; Tosi, M.; Thilker, D. A.; Lee, J. C.; Sabbi, E.; Kim, H.; Pellerin, A.

2018-05-01

One of the main theories for explaining the formation of spiral arms in galaxies is the stationary density wave theory. This theory predicts the existence of an age gradient across the arms. We use the stellar cluster catalogues of the galaxies NGC 1566, M51a, and NGC 628 from the Legacy Extragalactic UV Survey (LEGUS) program. In order to test for the possible existence of an age sequence across the spiral arms, we quantified the azimuthal offset between star clusters of different ages in our target galaxies. We found that NGC 1566, a grand-design spiral galaxy with bisymmetric arms and a strong bar, shows a significant age gradient across the spiral arms that appears to be consistent with the prediction of the stationary density wave theory. In contrast, M51a with its two well-defined spiral arms and a weaker bar does not show an age gradient across the arms. In addition, a comparison with non-LEGUS star cluster catalogues for M51a yields similar results. We believe that the spiral structure of M51a is not the result of a stationary density wave with a fixed pattern speed. Instead, tidal interactions could be the dominant mechanism for the formation of spiral arms. We also found no offset in the azimuthal distribution of star clusters with different ages across the weak spiral arms of NGC 628.

One arm exercise induces significant interarm diastolic blood pressure difference.

PubMed

Hong, Dezhi; Wang, Jiwei; Su, Hai; Xu, Jingsong; Liu, Yanna; Peng, Qiang; Wang, Lijuan

2011-06-01

This study is designed to investigate the inducing effect of one arm exercise on interarm difference (IAD) in the blood pressure (BP). Fifty healthy young participants were included in the study. Three-minute exercises of the right arm elbow flexion and extension were performed. The bilateral brachial BP was simultaneously measured with two automatic BP measurement devices before (basic) and immediately 0, 5, 10, 15, 20, and 30 min after exercise. The absolute difference in the systolic BP (SBP) and diastolic BP (DBP) between the left and right BP of at least 10 mmHg was recognized as sIAD and dIAD. The baseline data of the SBP and DBP in left and right arms revealed no significant difference (SBP: 110 ± 10 vs. 111 ± 11 mmHg; DBP: 66 ± 8 vs. 66 ± 9 mmHg, both not significant). The prevalence of dIAD was 2% at the baseline. However, this prevalence increased to 80% at 0 min, as right arm exercise induced the right DBP decrease and left DBP increase, and then the prevalence decreased gradually within a 30-min recovery period. The prevalence of sIAD was zero at the baseline and the maximal prevalence was 8% during the 20-min postexercise period. One arm exercise can lead to a significant IAD in DBP. Any arm exercise should be avoided before BP measurement.

Radial ooids from Great Salt Lake (Utah) as paleoenvironmental archives: Insights from radiocarbon chronology and stable isotopes

NASA Astrophysics Data System (ADS)

Paradis, O. P.; Corsetti, F. A.; Bardsley, A.; Hammond, D. E.; Xu, X.; Walker, J. C.

2017-12-01

Ooids (laminated, carbonate coated grains) are ubiquitous in the geologic record in marine and lacustrine settings, and thus remain a common target for geochemical analysis to understand modern and ancient aqueous environments. However, the processes governing ooid formation remain unclear. Recently, radiocarbon dating has revealed that modern marine ooids grow slowly (Beaupre et al. 2015), and laboratory experiments have highlighted the importance of sediment transport and abrasion on net growth rates and ooid size (Trower et al. 2017). Ooid cortex structure includes micritic, tangential and/or radially oriented fabrics. Most modern marine ooids have tangential or micritic cortices, whereas many ancient ooids have radial cortices—thus, there is a need to understand how radial ooids in ancient rocks might inform us about their depositional environment. The Great Salt Lake (GSL), Utah, provides a unique environment to assess the growth rate of primary radial aragonitic ooids. Ooids collected near Antelope Island in the south arm of GSL were sieved, the 355-500 µm fraction was sequentially leached, and 14C of the evolved gas was analyzed to provide a time series of growth. The oldest inorganic carbon of this size fraction has an apparent 14C age of 6600 yr BP, with subsequent growth spanning over 6,000 years. Closed-basin lakes are particularly susceptible to a "reservoir effect" which results in anomalously old apparent radiocarbon ages. The 14C age of the modern dissolved inorganic carbon (DIC) of the south arm was measured to be 295 yr BP, a reservoir age comparable to estimates from lacustrine cave carbonates (McGee et al. 2012). Net growth rate of south arm ooids ranges between 0.01-0.025 µm per year. The δ13C of the outermost cortex suggests that the ooids resemble the modern DIC in the south arm water, suggesting ooids precipitate in equilibrium with lake water. Finer-scale structure in the δ13C of the ooid cortex through time suggests lake level changed in a relative sense, with evidence for a higher lake altitude around 2700 yr BP. We conclude that 1) 14C-dating using sequential leaching methods indicates ooids began forming in Great Salt Lake over 6,000 yr BP and have continued to the present; and 2) lacustrine ooids are robust high-resolution paleoenvironmental archives when paired with radiochronology.

Shedding lights on the flexible-armed porphyrins: Human telomeric G4 DNA interaction and cell photocytotoxicity research.

PubMed

Sun, Xiang-Yu; Zhao, Ping; Jin, Shu-Fang; Liu, Min-Chao; Wang, Xia-Hong; Huang, Yu-Min; Cheng, Zhen-Feng; Yan, Si-Qi; Li, Yan-Yu; Chen, Ya-Qing; Zhong, Yan-Mei

2017-08-01

DNA polymorphism exerts a fascination on a large scientific community. Without crystallographic structural data, clarification of the binding modes between G-quadruplex (G4) and ligand (complex) is a challenging job. In the present work, three porphyrin compounds with different flexible carbon chains (arms) were designed, synthesized and characterized. Their binding, folding and stabilizing abilities to human telomeric G4 DNA structures were comparatively researched. Positive charges at the end of the flexible carbon chains seem to be favorable for the DNA-porphyrin interactions, which were evidenced by the spectral results and further confirmed by the molecular docking calculations. Biological function analysis demonstrated that these porphyrins show no substantial inhibition to Hela, A549 and BEL 7402 cancer cell lines under dark while exhibit broad inhibition under visible light. This significantly enhanced photocytotoxicity relative to the dark control is an essential property of photochemotherapeutic agents. The feature of the flexible arms emerges as critical influencing factors in the cell photocytotoxicity. Moreover, an ROS-mediated mitochondrial dysfunction pathway was suggested for the cell apoptosis induced by these flexible-armed porphyrins. It is found that the porphyrins with positive charges located at the end of the flexible arms represent an exciting opportunity for photochemotherapeutic anti-cancer drug design. Copyright © 2017. Published by Elsevier B.V.

A real-time robot arm collision detection system

NASA Technical Reports Server (NTRS)

Shaffer, Clifford A.; Herb, Gregory M.

1990-01-01

A data structure and update algorithm are presented for a prototype real time collision detection safety system for a multi-robot environment. The data structure is a variant of the octree, which serves as a spatial index. An octree recursively decomposes 3-D space into eight equal cubic octants until each octant meets some decomposition criteria. The octree stores cylspheres (cylinders with spheres on each end) and rectangular solids as primitives (other primitives can easily be added as required). These primitives make up the two seven degrees-of-freedom robot arms and environment modeled by the system. Octree nodes containing more than a predetermined number N of primitives are decomposed. This rule keeps the octree small, as the entire environment for the application can be modeled using a few dozen primitives. As robot arms move, the octree is updated to reflect their changed positions. During most update cycles, any given primitive does not change which octree nodes it is in. Thus, modification to the octree is rarely required. Incidents in which one robot arm comes too close to another arm or an object are reported. Cycle time for interpreting current joint angles, updating the octree, and detecting/reporting imminent collisions averages 30 milliseconds on an Intel 80386 processor running at 20 MHz.

Risk-aware multi-armed bandit problem with application to portfolio selection

PubMed Central

Huo, Xiaoguang

2017-01-01

Sequential portfolio selection has attracted increasing interest in the machine learning and quantitative finance communities in recent years. As a mathematical framework for reinforcement learning policies, the stochastic multi-armed bandit problem addresses the primary difficulty in sequential decision-making under uncertainty, namely the exploration versus exploitation dilemma, and therefore provides a natural connection to portfolio selection. In this paper, we incorporate risk awareness into the classic multi-armed bandit setting and introduce an algorithm to construct portfolio. Through filtering assets based on the topological structure of the financial market and combining the optimal multi-armed bandit policy with the minimization of a coherent risk measure, we achieve a balance between risk and return. PMID:29291122

Risk-aware multi-armed bandit problem with application to portfolio selection.

PubMed

Huo, Xiaoguang; Fu, Feng

2017-11-01

Sequential portfolio selection has attracted increasing interest in the machine learning and quantitative finance communities in recent years. As a mathematical framework for reinforcement learning policies, the stochastic multi-armed bandit problem addresses the primary difficulty in sequential decision-making under uncertainty, namely the exploration versus exploitation dilemma, and therefore provides a natural connection to portfolio selection. In this paper, we incorporate risk awareness into the classic multi-armed bandit setting and introduce an algorithm to construct portfolio. Through filtering assets based on the topological structure of the financial market and combining the optimal multi-armed bandit policy with the minimization of a coherent risk measure, we achieve a balance between risk and return.

A numerical study of the effects of bell pulsation dynamics and oral arms on the exchange currents generated by the upside-down jellyfish Cassiopea xamachana.

PubMed

Hamlet, Christina; Santhanakrishnan, Arvind; Miller, Laura A

2011-06-01

Mathematical and experimental studies of the flows generated by jellyfish have focused primarily on mechanisms of swimming. More recent work has also considered the fluid dynamics of feeding from currents generated during swimming. Here we capitalize on the benthic lifestyle of the upside-down jellyfish (Cassiopea xamachana) to explore the fluid dynamics of feeding uncoupled from swimming. A two-dimensional mathematical model is developed to capture the fundamental characteristics of the motion of the unique concave bell shape. Given the prominence of the oral arms, this structure is included and modeled as a porous layer that perturbs the flow generated by bell contractions. The immersed boundary method is used to solve the fluid-structure interaction problem. Velocity fields obtained from live organisms using digital particle image velocimetry were used to validate the numerical simulations. Parameter sweeps were used to numerically explore the effects of changes in pulse dynamics and the properties of the oral arms independently. Numerical experiments allow the opportunity to examine physical effects and limits within and beyond the biologically relevant range to develop a better understanding of the system. The presence of the prominent oral arm structures in the field of flow increased the flux of new fluid from along the substrate to the bell. The numerical simulations also showed that the presence of pauses between bell expansion and the next contraction alters the flow of the fluid over the bell and through the oral arms.

The Mobile Base System, part of the Canadian arm, is revealed inside the container

NASA Technical Reports Server (NTRS)

2000-01-01

With the lid removed, the wrapped Mobile Base System (MBS) is revealed inside its transport container. The MBS is part of the Canadian Space Agency's Space Station Remote Manipulator System (SSRMS), which is part of the payload on mission STS-100 to the International Space Station.

KSC-07pd2923

NASA Image and Video Library

2007-10-22

KENNEDY SPACE CENTER, FLA. -- On Launch Pad 39A on NASA's Kennedy Space Center, space shuttle Discovery is fully revealed after rollback of the rotating service structure, at far left. Next to it is the fixed service structure, or FSS, with the 80-foot-tall lightning mast on top. Extending from the FSS to the golden external tank is the vent hood (known as the "beanie cap") at the end of the gaseous oxygen vent arm. Vapors are created as the liquid oxygen in the external tank boil off. The hood vents the gaseous oxygen vapors away from the space shuttle vehicle. Below it, also extending toward Discovery from the structure, is the orbiter access arm with the White Room at the end. The crew gains access into the orbiter through the White Room. Rollback of the RSS started at 3:34 p.m. EDT and was complete at 4:20 p.m. The RSS provides protected access to the orbiter for changeout and servicing of payloads at the pad. Rollback of the pad's RSS is one of the milestones in preparation for the launch of mission STS-120. Discovery is scheduled for liftoff at 11:38 a.m. EDT on Oct. 23. The mission will be the 23rd assembly flight to the International Space Station and the 34th flight for Discovery. Payload on the mission is the Italian-built U.S. Node 2, called Harmony. The 14-day mission will install Harmony and move the P6 solar arrays to their permanent position and deploy them. Discovery is expected to complete its mission and return home at 4:47 a.m. EST on Nov. 6. Photo credit: NASA/Kim Shiflett

KSC-08pd1503

NASA Image and Video Library

2008-05-30

CAPE CANAVERAL, Fla. -- Against the dark sky, lights bathe space shuttle Discovery, revealed after rollback of the rotating service structure in preparation for launch on the STS-124 mission. First motion was at 8:33 p.m. and rollback was complete at 9:07 p.m. The rotating structure provides protected access to the shuttle for changeout and servicing of payloads at the pad. It is supported by a rotating bridge that pivots on a vertical axis on the west side of the pad's flame trench. After the RSS is rolled back, the orbiter is ready for fuel cell activation and external tank cryogenic propellant loading operations. The pad is cleared to the perimeter gate for operations to fill the external tank with about 500,000 gallons of cryogenic propellants used by the shuttle’s main engines. This is done at the pad approximately eight hours before the scheduled launch. Above the orange external tank is the oxygen vent hood, called the "beanie cap," at the end of the gaseous oxygen vent arm extending from the fixed service structure. Vapors are created as the liquid oxygen in the external tank boil off. The hood vents the gaseous oxygen vapors away from the space shuttle vehicle. Below is the orbiter access arm with the White Room at the end, flush against the shuttle. The White Room provides access into the shuttle. The STS-124 mission is the second of three flights launching components to complete the Japan Aerospace Exploration Agency's Kibo laboratory. The shuttle crew will install Kibo's large Japanese Pressurized Module and its remote manipulator system, or RMS. The 14-day flight includes three spacewalks. Launch is scheduled for 5:02 p.m. May 31. Photo credit: NASA/Troy Cryder

Cathodoluminescence studies of chevron features in semi-polar (11 2 ¯ 2 ) InGaN/GaN multiple quantum well structures

NASA Astrophysics Data System (ADS)

Brasser, C.; Bruckbauer, J.; Gong, Y.; Jiu, L.; Bai, J.; Warzecha, M.; Edwards, P. R.; Wang, T.; Martin, R. W.

2018-05-01

Epitaxial overgrowth of semi-polar III-nitride layers and devices often leads to arrowhead-shaped surface features, referred to as chevrons. We report on a study into the optical, structural, and electrical properties of these features occurring in two very different semi-polar structures, a blue-emitting multiple quantum well structure, and an amber-emitting light-emitting diode. Cathodoluminescence (CL) hyperspectral imaging has highlighted shifts in their emission energy, occurring in the region of the chevron. These variations are due to different semi-polar planes introduced in the chevron arms resulting in a lack of uniformity in the InN incorporation across samples, and the disruption of the structure which could cause a narrowing of the quantum wells (QWs) in this region. Atomic force microscopy has revealed that chevrons can penetrate over 150 nm into the sample and quench light emission from the active layers. The dominance of non-radiative recombination in the chevron region was exposed by simultaneous measurement of CL and the electron beam-induced current. Overall, these results provide an overview of the nature and impact of chevrons on the luminescence of semi-polar devices.

Arm-in-Arm Response Regulator Dimers Promote Intermolecular Signal Transduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baker, Anna W.; Satyshur, Kenneth A.; Moreno Morales, Neydis

2016-02-01

ABSTRACT Bacteriophytochrome photoreceptors (BphPs) and their cognate response regulators make up two-component signal transduction systems which direct bacteria to mount phenotypic responses to changes in environmental light quality. Most of these systems utilize single-domain response regulators to transduce signals through unknown pathways and mechanisms. Here we describe the photocycle and autophosphorylation kinetics of RtBphP1, a red light-regulated histidine kinase from the desert bacteriumRamlibacter tataouinensis. RtBphP1 undergoes red to far-red photoconversion with rapid thermal reversion to the dark state. RtBphP1 is autophosphorylated in the dark; this activity is inhibited under red light. The RtBphP1 cognate response regulator, theR. tataouinensisbacteriophytochrome response regulatormore » (RtBRR), and a homolog, AtBRR fromAgrobacterium tumefaciens, crystallize unexpectedly as arm-in-arm dimers, reliant on a conserved hydrophobic motif, hFWAhL (where h is a hydrophobic M, V, L, or I residue). RtBRR and AtBRR dimerize distinctly from four structurally characterized phytochrome response regulators found in photosynthetic organisms and from all other receiver domain homodimers in the Protein Data Bank. A unique cacodylate-zinc-histidine tag metal organic framework yielded single-wavelength anomalous diffraction phases and may be of general interest. Examination of the effect of the BRR stoichiometry on signal transduction showed that phosphorylated RtBRR is accumulated more efficiently than the engineered monomeric RtBRR (RtBRR mon) in phosphotransfer reactions. Thus, we conclude that arm-in-arm dimers are a relevant signaling intermediate in this class of two-component regulatory systems. IMPORTANCEBphP histidine kinases and their cognate response regulators comprise widespread red light-sensing two-component systems. Much work on BphPs has focused on structural understanding of light sensing and on enhancing the natural infrared fluorescence of these proteins, rather than on signal transduction or the resultant phenotypes. To begin to address this knowledge gap, we solved the crystal structures of two single-domain response regulators encoded by a region immediately downstream of that encoding BphPs. We observed a previously unknown arm-in-arm dimer linkage. Monomerization via deletion of the C-terminal dimerization motif had an inhibitory effect on net response regulator phosphorylation, underlining the importance of these unusual dimers for signal transduction.« less

Simultaneous targeting of insulin-like growth factor-1 receptor and anaplastic lymphoma kinase in embryonal and alveolar rhabdomyosarcoma: a rational choice.

PubMed

van Gaal, J Carlijn; Roeffen, Melissa H S; Flucke, Uta E; van der Laak, Jeroen A W M; van der Heijden, Gwen; de Bont, Eveline S J M; Suurmeijer, Albert J H; Versleijen-Jonkers, Yvonne M H; van der Graaf, Winette T A

2013-11-01

Rhabdomyosarcoma (RMS) is an aggressive soft tissue tumour mainly affecting children and adolescents. Since survival of high-risk patients remains poor, new treatment options are awaited. The aim of this study is to investigate anaplastic lymphoma kinase (ALK) and insulin-like growth factor-1 receptor (IGF-1R) as potential therapeutic targets in RMS. One-hundred-and-twelve primary tumours (embryonal RMS (eRMS)86; alveolar RMS (aRMS)26) were collected. Expression of IGF-1R, ALK and downstream pathway proteins was evaluated by immunohistochemistry. The effect of ALK inhibitor NVP-TAE684 (Novartis), IGF-1R antibody R1507 (Roche) and combined treatment was investigated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays in cell lines (aRMS Rh30, Rh41; eRMS Rh18, RD). IGF-1R and ALK expression was observed in 72% and 92% of aRMS and 61% and 39% of eRMS, respectively. Co-expression was observed in 68% of aRMS and 32% of eRMS. Nuclear IGF-1R expression was an adverse prognostic factor in eRMS (5-year survival 46.9 ± 18.7% versus 84.4 ± 5.9%, p=0.006). In vitro, R1507 showed diminished viability predominantly in Rh41. NVP-TAE684 showed diminished viability in Rh41 and Rh30, and to a lesser extent in Rh18 and RD. Simultaneous treatment revealed synergistic activity against Rh41 and Rh30. Co-expression of IGF-1R and ALK is detected in eRMS and particularly in aRMS. As combined inhibition reveals synergistic cytotoxic effects, this combination seems promising and needs further investigation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Upper limb discomfort profile due to intermittent isometric pronation torque at different postural combinations of the shoulder-arm system.

PubMed

Mukhopadhyay, Prabir; O'Sullivan, Leonard W; Gallwey, Timothy J

2009-05-01

Twenty-seven right-handed male university students participated in this study, which comprised a full factorial model consisting of three forearm rotation angles (60% prone and supine and neutral range of motion), three elbow angles (45 degrees , 90 degrees and 135 degrees ), three upper arm angles (45 degrees flexion/extension and neutral), one exertion frequency (15 per min) and one level of pronation torque (20% maximum voluntary contraction (MVC) relative to MVC at each articulation). Discomfort rating after the end of each 5 min treatment was recorded on a visual analogue scale. Results of a repeated measures analysis of covariance on discomfort score, with torque endurance time as covariate, indicated that none of the factors was significant including torque endurance time (p = 0.153). An initial data collection phase preceded the main experiment in order to ensure that participants exerted exactly 20% MVC of the particular articulation. In this phase MVC pronation torque was measured at each articulation. The data revealed a significant forearm rotation angle effect (p = 0.001) and participant effect (p = 0.001). Of the two-way interactions, elbow*participant (p = 0.004), forearm*participant (p = 0.001) and upper arm*participant (p = 0.005) were the significant factors. Electromyographic activity of the pronator teres and biceps brachii muscles revealed no significant change in muscle activity in most of the articulations. Industrial jobs involving deviated upper arm postures are typical in industry but have a strong association with injury. Data from this study will enable better understanding of the effects of deviated upper arm postures on musculoskeletal disorders and can also be used to identify and control high-risk tasks in industry.

The effectiveness of thyme honey for the management of treatment-induced xerostomia in head and neck cancer patients: A feasibility randomized control trial.

PubMed

Charalambous, Andreas; Lambrinou, Ekaterini; Katodritis, Nicos; Vomvas, Dimitrios; Raftopoulos, Vasilios; Georgiou, Morpho; Paikousis, Lefkios; Charalambous, Melanie

2017-04-01

Radiation-induced xerostomia is one of the most common side effects that head and neck cancer patients experience during and after treatment. Despite the various methods for the prevention and treatment of radiation-induced xerostomia, it remains highly prevalent among patients treated for head and neck cancers negatively influencing their lives. The purpose of this study was to evaluate the effectiveness of thyme honey as a means for managing radiation-induced xerostomia. This was a parallel randomised controlled trial with two equal arms, the experimental arm (thyme honey) and the control arm (saline). 72 head and neck cancer patients receiving radiotherapy or/and chemotherapy or/and surgery were recruited in a specialised cancer centre. Patients in both arms followed the same administration protocol with thyme honey and saline respectively. Identical assessments at baseline, 1 month and 6 months following completion of the intervention were performed in both arms including the National Cancer Institute (NCI) xerostomia scale and the Xerostomia Questionnaire (XQ) additionally to weekly oral clinical assessments. The ClinicalTrials.gov Identifier for this study is NCT01465308. Linear Mixed Models revealed the statistically significant effect of the intervention on xerostomia (F = 8.474 p < 0.001) and overall quality of life (F = 13.158 p < 0.001). Moreover, Generalised Estimating Equations revealed a statistically significant effect on strong and unbearable pain (F = 10.524 p < 0.001) and dysphagia (F = 4.525 p = 0.033). The study has demonstrated the safety and efficacy findings of Thyme honey in head and neck cancer patients for the management of treatment induced xerostomia. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of biomotor structures on performance of competitive gymnastics elements in elementary school female sixth-graders.

PubMed

Delas, Suncica; Babin, Josip; Katić, Ratko

2007-12-01

In order to identify biomotor systems that determine performance of competitive gymnastics elements in elementary school female sixth-graders, factor structures of morphological characteristics and basic motor abilities were determined first, followed by relations of the morphological-motor system factors obtained with a set of criterion variables evaluating specific motor skills in competitive gymnastics in 126 female children aged 12 years +/- 3 months. Factor analysis of 17 morphological measures yielded three morphological factors: factor of mesoendomorphy and/or adipose body voluminosity; factor of longitudinal body dimensionality; and factor of transverse arm dimensionality. Factor analysis of 16 motor variables produced four motor factors: general motoricity factor (motor system); general speed factor; factor of explosive strength of throwing type (arm explosiveness); and factor of arm and leg flexibility. Three significant canonical correlations, i.e. linear combinations, explained the association between the set of seven latent variables of the morphological and basic motor system, and five variables evaluating the knowledge in competitive gymnastics. The first canonical linear combination was based on a favorable and predominant impact of the general motor factor (a system integrating whole body coordination, leg explosiveness, relative arm strength, arm movement frequency and body flexibility) on performance of gymnastics elements, cartwheel, handstand and backward pullover mount in particular, and to a lesser extent front scale and double leg pirouette for 180 degrees. The relation of the second pair of canonical factors additionally explained the role of transverse dimensionality of arm skeleton, arm flexibility and explosiveness in performing cartwheel and squat vault, whereas the relation of the third pair of canonical factors explained the unfavorable impact of adipose voluminosity on the performance of squat vault and backward pullover mount.

Design and simulation of an articulated surgical arm for guiding stereotactic neurosurgery

NASA Astrophysics Data System (ADS)

Kadi, A. Majeed; Zamorano, Lucia J.; Frazer, Matthew P.; Lu, Yi

1992-03-01

In stereotactic surgery, the need exists for means of relating intraoperatively the position and orientation of the surgical instrument used by the neurosurgeon to a known frame of reference. An articulated arm is proposed which would provide the neurosurgeon with on-line information for position, and orientation of the surgical tools being moved by the neurosurgeon. The articulated arm has six degrees of freedom, with five revolute and one prismatic joints. The design features include no obstruction to the field of view, lightweight, good balance against gravity, an accuracy of 1 mm spherical error probability (SEP), and a solvable kinematic structure making it capable of fitting the operating room environment. The arm can be mounted on either the surgical table or the stereotactic frame. A graphical simulation of the arm was created using the IGRIP simulation package created by Deneb Robotics. The simulation demonstrates the use of the arm, mounted on several positions of the ring reaching various target points within the cranium.

The Effect of Playing Different Musical Instruments on Arm Asymmetry

ERIC Educational Resources Information Center

Kaya, E. Erdem

2015-01-01

Between the two hemispheres of the brain, structural and functional differences are called cerebral lateralization that can affect the skill performance of both arms in a different way, which is called handedness. Approximately 90% of people are right-handed and they use the right hand for most skillful activities. Interestingly, recent studies…

[Incidence and severity of the digestive system diseases in the armed forces of Ukraine].

PubMed

Rozhkov, H S

2012-01-01

The paper presents an analysis of the level and structure of morbidity Armed Forces of Ukraine diseases of the digestive system. The highest rates of total incidence of disease in the class XI 2008-2011, recorded among conscripts, the lowest--in the military under the contract.

Simulating Macrosegregation in Var Ingots of Titanium Alloy During Solidification

DTIC Science & Technology

2006-06-01

spacings in Ti- 6Al - 4V were estimated. A summary-status of the use of software by VAR titanium -ingot producers in the USA is also given. In its...Ti- 6Al - 4V with a melting condition provided by RMI Titanium Company (Proposed Case 11). Two ingots are simulated; one is simulated assuming a...revealed a more intense band. Since primary arm spacings in titanium alloys are not available, primary dendrite arm spacings in Ti-6A1- 4V were

Polyphosphazene Based Star-Branched and Dendritic Molecular Brushes.

PubMed

Henke, Helena; Posch, Sandra; Brüggemann, Oliver; Teasdale, Ian

2016-05-01

A new synthetic procedure is described for the preparation of poly(organo)phosphazenes with star-branched and star dendritic molecular brush type structures, thus describing the first time it has been possible to prepare controlled, highly branched architectures for this type of polymer. Furthermore, as a result of the extremely high-arm density generated by the phosphazene repeat unit, the second-generation structures represent quite unique architectures for any type of polymer. Using two relativity straight forward iterative syntheses it is possible to prepare globular highly branched polymers with up to 30 000 functional end groups, while keeping relatively narrow polydispersities (1.2-1.6). Phosphine mediated polymerization of chlorophosphoranimine is first used to prepare three-arm star polymers. Subsequent substitution with diphenylphosphine moieties gives poly(organo)phosphazenes to function as multifunctional macroinitiators for the growth of a second generation of polyphosphazene arms. Macrosubstitution with Jeffamine oligomers gives a series of large, water soluble branched macromolecules with high-arm density and hydrodynamic diameters between 10 and 70 nm. © 2016 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Extravehicular activity translation arm (EVATA) study

NASA Technical Reports Server (NTRS)

Preiswerk, P. R.; Stammreich, J. R.

1978-01-01

The preliminary design of a deployable Extravehicular Activity Translation Arm (EVATA) assembly which will allow an EVA crewman to perform tasks in the vicinity of the External TNK (ET) umbilical doors and to inspect most of the underside of the shuttle spacecraft is reported. The concept chosen for the boom structure was the Astro Extendable Support Structure (ESS) which formed the main structure for the Synthetic Aperture Radar (SAR) Antenna System on the SEASAT A spacecraft. This structure is a deployable triangular truss. A comparison of the EVATA and the SEASAT A ESS is shown. The development of status of the ESS is shown. The satellite configuration, the stowed truss load path, and the envelope deployment sequence for the ESS are also shown.

Dendrites fragmentation induced by oscillating cavitation bubbles in ultrasound field.

PubMed

Wang, S; Kang, J; Zhang, X; Guo, Z

2018-02-01

The fragmentation of the dendrites of succinonitrile (SCN)-2-wt.% acetone organic transparent alloy caused by ultrasound-induced cavitation bubbles was studied by using ultra-high-speed digital camera with a rate of 40,000fps. Real-time imaging reveals that the vibrating cavitation bubbles can fragment not only secondary arms but also the primary ones under high ultrasound power. The secondary arms always broke at their roots as a result of stress concentration induced by oscillated cavitation bubble and then ripped off from their primary arms. Generally the fragment process takes tens of milliseconds from bending to breaking, while the break always occurs immediately in less than 25μs. Copyright © 2017. Published by Elsevier B.V.

Breakdown of the balanced lethals in Rhoeo: the structure of the Alethal Renner complex of the homozygotic stock of Rhoeo.

PubMed

Golczyk, H

2011-01-01

Fluorescence in situ hybridization, base-specific fluorescence, C-banding and silver-staining were performed to reveal the cyto-molecular constitution of the karyotype in the bivalent-forming Rhoeo spathacea concolor. It was shown that the genome of this form is almost identical to the β-complex of the ring-forming rhoeos. In spite of some modifications in the arrangement of a few distal rDNA sites and in the amount of pericentromeric AT-rich heterochromatin, the alethal genome of the bivalent-forming Rhoeo seems segmentally unaltered. Thus, the breakdown of balanced lethals in Rhoeo is most likely uncoupled from creating new chromosome arm combinations. Copyright © 2011 S. Karger AG, Basel.

The Carina Nebula and Gum 31 molecular complex - II. The distribution of the atomic gas revealed in unprecedented detail

NASA Astrophysics Data System (ADS)

Rebolledo, David; Green, Anne J.; Burton, Michael; Brooks, Kate; Breen, Shari L.; Gaensler, B. M.; Contreras, Yanett; Braiding, Catherine; Purcell, Cormac

2017-12-01

We report high spatial resolution observations of the H I 21cm line in the Carina Nebula and the Gum 31 region obtained with the Australia Telescope Compact Array. The observations covered ∼12 °^2 centred on l = 287.5°, b = -1°, achieving an angular resolution of ∼35 arcsec. The H I map revealed complex filamentary structures across a wide range of velocities. Several 'bubbles' are clearly identified in the Carina Nebula complex, produced by the impact of the massive star clusters located in this region. An H I absorption profile obtained towards the strong extragalactic radio source PMN J1032-5917 showed the distribution of the cold component of the atomic gas along the Galactic disc, with the Sagittarius-Carina and Perseus spiral arms clearly distinguishable. Preliminary calculations of the optical depth and spin temperatures of the cold atomic gas show that the H I line is opaque (τ ≳ 2) at several velocities in the Sagittarius-Carina spiral arm. The spin temperature is ∼100 K in the regions with the highest optical depth, although this value might be lower for the saturated components. The atomic mass budget of Gum 31 is ∼35 per cent of the total gas mass. H I self-absorption features have molecular counterparts and good spatial correlation with the regions of cold dust as traced by the infrared maps. We suggest that in Gum 31 regions of cold temperature and high density are where the atomic to molecular gas-phase transition is likely to be occurring.

Identification of nucleolus-associated chromatin domains reveals the role of the nucleolus in the 3D organisation of the A. thaliana genome

PubMed Central

Pontvianne, Frédéric; Carpentier, Marie-Christine; Durut, Nathalie; Pavlištová, Veronika; Jaške, Karin; Schořová, Šárka; Parrinello, Hugues; Rohmer, Marine; Pikaard, Craig S; Fojtová, Miloslava; Fajkus, Jiří; Saez-Vasquez, Julio

2017-01-01

The nucleolus is the site of ribosomal RNA (rRNA) gene transcription, rRNA processing and ribosome biogenesis. However, the nucleolus also plays additional roles in the cell. We isolated nucleoli by Fluorescence Activated Cell Sorting (FACS) and identified Nucleolus-Associated Chromatin Domains (NADs) by deep sequencing, comparing wild-type plants and null mutants for the nucleolar protein, NUCLEOLIN 1 (NUC1). NADs are primarily genomic regions with heterochromatic signatures and include transposable elements (TEs), sub-telomeric regions and mostly inactive protein-coding genes. However, NADs also include active ribosomal RNA genes, and the entire short arm of chromosome 4 adjacent to them. In nuc1 null mutants, which alter rRNA gene expression and overall nucleolar structure, NADs are altered, telomere association with the nucleolus is decreased and telomeres become shorter. Collectively, our studies reveal roles for NUC1 and the nucleolus in the spatial organization of chromosomes as well as telomere maintenance. PMID:27477271

Cloning of a new member of the insulin gene superfamily (INSL4) expressed in human placenta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chassin, D.; Laurent, A.; Janneau, J.L.

1995-09-20

A new member of the insulin gene superfamily was identified by screening a subtracted cDNA library of first-trimester human placenta and, hence, was tentatively named early placenta insulin-like peptide (EPIL). In this paper, we report the cloning and sequencing of the EPIL cDNA and the EPIL gene (INSL4). Comparison of the deduced amino acid sequence of the early placenta insulin-like peptide revealed significant overall and structural homologies with members of the insulin-like hormone superfamily. Moreover, the organization of the early placenta insulin-like gene, which is composed of two exons and one intron, is similiar to that of insulin and relaxin.more » By in situ hybridization, the INSL4 gene was assigned to band p24 of the short arm of chromosome 9. RT-PCR analysis of EPIL tissue distribution revealed that its transcripts are expressed in the placenta and uterus. 22 refs., 3 figs.« less

Loss-of-Function Mutations in a Human Gene Related to Chlamydomonas reinhardtii Dynein IC78 Result in Primary Ciliary Dyskinesia

PubMed Central

Pennarun, Gaëlle; Escudier, Estelle; Chapelin, Catherine; Bridoux, Anne-Marie; Cacheux, Valère; Roger, Gilles; Clément, Annick; Goossens, Michel; Amselem, Serge; Duriez, Bénédicte

1999-01-01

Summary Primary ciliary dyskinesia (PCD) is a group of heterogeneous disorders of unknown origin, usually inherited as an autosomal recessive trait. Its phenotype is characterized by axonemal abnormalities of respiratory cilia and sperm tails leading to bronchiectasis and sinusitis, which are sometimes associated with situs inversus (Kartagener syndrome) and male sterility. The main ciliary defect in PCD is an absence of dynein arms. We have isolated the first gene involved in PCD, using a candidate-gene approach developed on the basis of documented abnormalities of immotile strains of Chlamydomonas reinhardtii, which carry axonemal ultrastructural defects reminiscent of PCD. Taking advantage of the evolutionary conservation of genes encoding axonemal proteins, we have isolated a human sequence (DNAI1) related to IC78, a C. reinhardtii gene encoding a dynein intermediate chain in which mutations are associated with the absence of outer dynein arms. DNAI1 is highly expressed in trachea and testis and is composed of 20 exons located at 9p13-p21. Two loss-of-function mutations of DNAI1 have been identified in a patient with PCD characterized by immotile respiratory cilia lacking outer dynein arms. In addition, we excluded linkage between this gene and similar PCD phenotypes in five other affected families, providing a clear demonstration of locus heterogeneity. These data reveal the critical role of DNAI1 in the development of human axonemal structures and open up new means for identification of additional genes involved in related developmental defects. PMID:10577904

Complex distal 10q rearrangement in a girl with mild intellectual disability: follow up of the patient and review of the literature of non-acrocentric satellited chromosomes.

PubMed

Sarri, Catherine; Douzgou, Sofia; Gyftodimou, Yolanda; Tümer, Zeynep; Ravn, Kirstine; Pasparaki, Angela; Sarafidou, Theologia; Kontos, Harry; Kokotas, Haris; Karadima, Georgia; Grigoriadou, Maria; Pandelia, Effie; Theodorou, Virginia; Moschonas, Nicholas K; Petersen, Michael B

2011-11-01

We report on an intellectually disabled girl with a de novo satellited chromosome 10 (10qs) and performed a review of the literature of the non-acrocentric satellited chromosomes (NASC). Satellites and stalks normally occur on the short arms of acrocentric chromosomes; however, the literature cites several reports of satellited non-acrocentric chromosomes, which presumably result from a translocation with an acrocentric chromosome. This is, to our knowledge, the third report of a 10qs chromosome. The phenotype observed in the proband prompted a search for a structural rearrangement of chromosome 10q. By microsatellite analysis we observed a 4 Mb deletion on the long arm of chromosome 10, approximately 145 kb from the telomere. FISH and array CGH analyses revealed a complex rearrangement involving in range from the centromere to the telomere: A 9.64 Mb 10q26.11-q26.2 duplication, a 1.3 Mb region with no copy number change, followed by a 5.62 Mb 10q26.2-q26.3 deletion and a translocation of satellite material. The homology between the repeat sequences at 10q subtelomere region and the sequences on the acrocentric short arms may explain the origin of the rearrangement and it is likely that the submicroscopic microdeletion and microduplication are responsible for the abnormal phenotype in our patient. The patient presented here, with a 15-year follow-up, manifests a distinct phenotype different from the 10q26 pure distal monosomy and trisomy syndromes. Copyright © 2011 Wiley Periodicals, Inc.

Salmonid Chromosome Evolution as Revealed by a Novel Method for Comparing RADseq Linkage Maps

PubMed Central

Gosselin, Thierry; Normandeau, Eric; Lamothe, Manuel; Isabel, Nathalie; Audet, Céline; Bernatchez, Louis

2016-01-01

Whole genome duplication (WGD) can provide material for evolutionary innovation. Family Salmonidae is ideal for studying the effects of WGD as the ancestral salmonid underwent WGD relatively recently, ∼65 Ma, then rediploidized and diversified. Extensive synteny between homologous chromosome arms occurs in extant salmonids, but each species has both conserved and unique chromosome arm fusions and fissions. Assembly of large, outbred eukaryotic genomes can be difficult, but structural rearrangements within such taxa can be investigated using linkage maps. RAD sequencing provides unprecedented ability to generate high-density linkage maps for nonmodel species, but can result in low numbers of homologous markers between species due to phylogenetic distance or differences in library preparation. Here, we generate a high-density linkage map (3,826 markers) for the Salvelinus genera (Brook Charr S. fontinalis), and then identify corresponding chromosome arms among the other available salmonid high-density linkage maps, including six species of Oncorhynchus, and one species for each of Salmo, Coregonus, and the nonduplicated sister group for the salmonids, Northern Pike Esox lucius for identifying post-duplicated homeologs. To facilitate this process, we developed MapComp to identify identical and proximate (i.e. nearby) markers between linkage maps using a reference genome of a related species as an intermediate, increasing the number of comparable markers between linkage maps by 5-fold. This enabled a characterization of the most likely history of retained chromosomal rearrangements post-WGD, and several conserved chromosomal inversions. Analyses of RADseq-based linkage maps from other taxa will also benefit from MapComp, available at: https://github.com/enormandeau/mapcomp/ PMID:28173098

Feedback attitude sliding mode regulation control of spacecraft using arm motion

NASA Astrophysics Data System (ADS)

Shi, Ye; Liang, Bin; Xu, Dong; Wang, Xueqian; Xu, Wenfu

2013-09-01

The problem of spacecraft attitude regulation based on the reaction of arm motion has attracted extensive attentions from both engineering and academic fields. Most of the solutions of the manipulator’s motion tracking problem just achieve asymptotical stabilization performance, so that these controllers cannot realize precise attitude regulation because of the existence of non-holonomic constraints. Thus, sliding mode control algorithms are adopted to stabilize the tracking error with zero transient process. Due to the switching effects of the variable structure controller, once the tracking error reaches the designed hyper-plane, it will be restricted to this plane permanently even with the existence of external disturbances. Thus, precise attitude regulation can be achieved. Furthermore, taking the non-zero initial tracking errors and chattering phenomenon into consideration, saturation functions are used to replace sign functions to smooth the control torques. The relations between the upper bounds of tracking errors and the controller parameters are derived to reveal physical characteristic of the controller. Mathematical models of free-floating space manipulator are established and simulations are conducted in the end. The results show that the spacecraft’s attitude can be regulated to the position as desired by using the proposed algorithm, the steady state error is 0.000 2 rad. In addition, the joint tracking trajectory is smooth, the joint tracking errors converges to zero quickly with a satisfactory continuous joint control input. The proposed research provides a feasible solution for spacecraft attitude regulation by using arm motion, and improves the precision of the spacecraft attitude regulation.

Crystal structure of Pseudomonas aeruginosa bacteriophytochrome: Photoconversion and signal transduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Xiaojing; Kuk, Jane; Moffat, Keith

2008-11-12

Phytochromes are red-light photoreceptors that regulate light responses in plants, fungi, and bacteria via reversible photoconversion between red (Pr) and far-red (Pfr) light-absorbing states. Here we report the crystal structure at 2.9 {angstrom} resolution of a bacteriophytochrome from Pseudomonas aeruginosa with an intact, fully photoactive photosensory core domain in its dark-adapted Pfr state. This structure reveals how unusual interdomain interactions, including a knot and an 'arm' structure near the chromophore site, bring together the PAS (Per-ARNT-Sim), GAF (cGMP phosphodiesterase/adenyl cyclase/FhlA), and PHY (phytochrome) domains to achieve Pr/Pfr photoconversion. The PAS, GAF, and PHY domains have topologic elements in common andmore » may have a single evolutionary origin. We identify key interactions that stabilize the chromophore in the Pfr state and provide structural and mutational evidence to support the essential role of the PHY domain in efficient Pr/Pfr photoconversion. We also identify a pair of conserved residues that may undergo concerted conformational changes during photoconversion. Modeling of the full-length bacteriophytochrome structure, including its output histidine kinase domain, suggests how local structural changes originating in the photosensory domain modulate interactions between long, cross-domain signaling helices at the dimer interface and are transmitted to the spatially distant effector domain, thereby regulating its histidine kinase activity.« less

Extrinsic and intrinsic index finger muscle attachments in an OpenSim upper-extremity model.

PubMed

Lee, Jong Hwa; Asakawa, Deanna S; Dennerlein, Jack T; Jindrich, Devin L

2015-04-01

Musculoskeletal models allow estimation of muscle function during complex tasks. We used objective methods to determine possible attachment locations for index finger muscles in an OpenSim upper-extremity model. Data-driven optimization algorithms, Simulated Annealing and Hook-Jeeves, estimated tendon locations crossing the metacarpophalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints by minimizing the difference between model-estimated and experimentally-measured moment arms. Sensitivity analysis revealed that multiple sets of muscle attachments with similar optimized moment arms are possible, requiring additional assumptions or data to select a single set of values. The most smooth muscle paths were assumed to be biologically reasonable. Estimated tendon attachments resulted in variance accounted for (VAF) between calculated moment arms and measured values of 78% for flex/extension and 81% for ab/adduction at the MCP joint. VAF averaged 67% at the PIP joint and 54% at the DIP joint. VAF values at PIP and DIP joints partially reflected the constant moment arms reported for muscles about these joints. However, all moment arm values found through optimization were non-linear and non-constant. Relationships between moment arms and joint angles were best described with quadratic equations for tendons at the PIP and DIP joints.

ARM Tethered Balloon System & AALCO Activities at AMF3 Site at Oliktok Point, AK

NASA Astrophysics Data System (ADS)

Hardesty, J.; Dexheimer, D.; Mei, F.; Roesler, E. L.; Longbottom, C.; Hillman, B. R.

2017-12-01

Sandia National Laboratories (SNL) has operated the Atmospheric Radiation Measurement program's (ARM) third ARM Mobile Facility (AMF3) and the restricted airspace associated with it at Oliktok Point, Alaska, since October 2013. The site hosts ground-based instrumentation which collects a variety of continuous atmospheric measurements as well as user-conducted unmanned aircraft and tethered balloon campaigns. SNL has operated ARM's tethered balloon system (TBS) as part of the Inaugural Campaigns for ARM Research using Unmanned Systems (ICARUS) since 2016. AALCO (Aerial Assessment of Liquid in Clouds at Oliktok), is an ARM Intensive Operations Period conducted by SNL at the AMF3 since 2016. The operation of the TBS during ICARUS and AALCO to altitudes above 4,000' AGL in a variety of seasons and conditions is addressed. A Distributed Temperature Sensing (DTS) system and supercooled liquid water content (SLWC) sensors have been deployed under both campaigns. The performance of these sensors is discussed and results are presented. DTS measurements and their relationship to concurrent temperature measurements from unmanned aircraft and radiosondes are shown. SLWC sensor in situ measurements are compared with microwave radiometer and radiosonde-derived measurements. Preliminary analysis of using Large Eddy Simulations to compare with the SLWC measurements reveals three-dimensional properties of the observed clouds.

The Influence of Dopaminergic Striatal Innervation on Upper Limb Locomotor Synergies

PubMed Central

Isaias, Ioannis U.; Volkmann, Jens; Marzegan, Alberto; Marotta, Giorgio; Cavallari, Paolo; Pezzoli, Gianni

2012-01-01

To determine the role of striatal dopaminergic innervation on upper limb synergies during walking, we measured arm kinematics in 13 subjects with Parkinson disease. Patients were recruited according to several inclusion criteria to represent the best possible in vivo model of dopaminergic denervation. Of relevance, we included only subjects with normal spatio-temporal parameters of the stride and gait speed to avoid an impairment of upper limbs locomotor synergies as a consequence of gait impairment per se. Dopaminergic innervation of the striatum was measured by FP-CIT and SPECT. All patients showed a reduction of gait-associated arms movement. No linear correlation was found between arm ROM reduction and contralateral dopaminergic putaminal innervation loss. Still, a partition analysis revealed a 80% chance of reduced arm ROM when putaminal dopamine content loss was >47%. A significant correlation was described between the asymmetry indices of the swinging of the two arms and dopaminergic striatal innervation. When arm ROM was reduced, we found a positive correlation between upper-lower limb phase shift modulation (at different gait velocities) and striatal dopaminergic innervation. These findings are preliminary evidence that dopaminergic striatal tone plays a modulatory role in upper-limb locomotor synergies and upper-lower limb coupling while walking at different velocities. PMID:23236504

Feedforward motor control in developmental dyslexia and developmental coordination disorder: Does comorbidity matter?

PubMed

Cignetti, Fabien; Vaugoyeau, Marianne; Fontan, Aurelie; Jover, Marianne; Livet, Marie-Odile; Hugonenq, Catherine; Audic, Frédérique; Chabrol, Brigitte; Assaiante, Christine

2018-05-01

Feedforward and online controls are two facets of predictive motor control from internal models, which is suspected to be impaired in learning disorders. We examined whether the feedforward component is affected in children (8-12 years) with developmental dyslexia (DD) and/or with developmental coordination disorder (DCD) compared to typically developing (TD) children. Children underwent a bimanual unloading paradigm during which a load supported to one arm, the postural arm, was either unexpectedly unloaded by a computer or voluntary unloaded by the subject with the other arm. All children showed a better stabilization (lower flexion) of the postural arm and an earlier inhibition of the arm flexors during voluntary unloading, indicating anticipation of unloading. Between-group comparisons of kinematics and electromyographic activity of the postural arm revealed that the difference during voluntary unloading was between DD-DCD children and the other groups, with the former showing a delayed inhibition of the flexor muscles. Deficit of the feedforward component of motor control may particularly apply to comorbid subtypes, here the DD-DCD subtype. The development of a comprehensive framework for motor performance deficits in children with learning disorders will be achieved only by dissociating key components of motor prediction and focusing on subtypes and comorbidities. Copyright © 2018 Elsevier Ltd. All rights reserved.

The unstructured linker arms of Mlh1-Pms1 are important for interactions with DNA during mismatch repair

PubMed Central

Plys, Aaron J.; Rogacheva, Maria V.; Greene, Eric C.; Alani, Eric

2012-01-01

DNA mismatch repair (MMR) models have proposed that MSH proteins identify DNA polymerase errors while interacting with the DNA replication fork. MLH proteins (primarily Mlh1-Pms1 in baker’s yeast) then survey the genome for lesion-bound MSH proteins. The resulting MSH-MLH complex formed at a DNA lesion initiates downstream steps in repair. MLH proteins act as dimers and contain long (20 – 30 nanometers) unstructured arms that connect two terminal globular domains. These arms can vary between 100 to 300 amino acids in length, are highly divergent between organisms, and are resistant to amino acid substitutions. To test the roles of the linker arms in MMR, we engineered a protease cleavage site into the Mlh1 linker arm domain of baker’s yeast Mlh1-Pms1. Cleavage of the Mlh1 linker arm in vitro resulted in a defect in Mlh1-Pms1 DNA binding activity, and in vivo proteolytic cleavage resulted in a complete defect in MMR. We then generated a series of truncation mutants bearing Mlh1 and Pms1 linker arms of varying lengths. This work revealed that MMR is greatly compromised when portions of the Mlh1 linker are removed, whereas repair is less sensitive to truncation of the Pms1 linker arm. Purified complexes containing truncations in Mlh1 and Pms1 linker arms were analyzed and found to have differential defects in DNA binding that also correlated with the ability to form a ternary complex with Msh2-Msh6 and mismatch DNA. These observations are consistent with the unstructured linker domains of MLH proteins providing distinct interactions with DNA during MMR. PMID:22659005

Secreted frizzled related protein 3 (SFRP3) is required for tumorigenesis of PAX3-FOXO1-positive alveolar rhabdomyosarcoma

PubMed Central

Kephart, Julie J.G.; Tiller, Rosanne G.J.; Crose, Lisa E.S.; Slemmons, Katherine K.; Chen, Po-Han; Hinson, Ashley R.; Bentley, Rex C.; Chi, Jen-Tsan Ashley; Linardic, Corinne M.

2015-01-01

Purpose Rhabdomyosarcoma is a soft tissue sarcoma associated with the skeletal muscle lineage. Of the two predominant subtypes, known as embryonal (eRMS) and alveolar (aRMS), aRMS has the poorer prognosis, with a 5-year survival rate of <50%. The majority of aRMS tumors express the fusion protein PAX3-FOXO1. As PAX3-FOXO1 has proven chemically intractable, the current study aims to identify targetable proteins that are downstream from or cooperate with PAX3-FOXO1 to support tumorigenesis. Experimental Design Microarray analysis of the transcriptomes of human skeletal muscle myoblasts expressing PAX3-FOXO1 revealed alteration of several Wnt pathway gene members, including secreted frizzled related protein 3 (SFRP3), a secreted Wnt pathway inhibitor. Loss-of-function using shRNAs against SFRP3 were used to interrogate the role of SFRP3 in human aRMS cell lines in vitro and conditional murine xenograft systems in vivo. The combination of SFRP3 genetic suppression and the chemotherapeutic agent vincristine was also examined. Results In vitro, suppression of SFRP3 inhibited aRMS cell growth, reduced proliferation accompanied by a G1 arrest and induction of p21, and induced apoptosis. In vivo, doxycycline-inducible suppression of SFRP3 reduced aRMS tumor growth and weight by more than three-fold, in addition to increasing myogenic differentiation and β-catenin signaling. The combination of SFRP3 suppression and vincristine was more effective at reducing aRMS cell growth in vitro than either treatment alone, and ablated tumorigenesis in vivo. Conclusions SFRP3 is necessary for the growth of human aRMS cells both in vitro and in vivo and is a promising new target for investigation in aRMS. PMID:26071485

Secreted Frizzled-Related Protein 3 (SFRP3) Is Required for Tumorigenesis of PAX3-FOXO1-Positive Alveolar Rhabdomyosarcoma.

PubMed

Kephart, Julie J G; Tiller, Rosanne G J; Crose, Lisa E S; Slemmons, Katherine K; Chen, Po-Han; Hinson, Ashley R; Bentley, Rex C; Chi, Jen-Tsan Ashley; Linardic, Corinne M

2015-11-01

Rhabdomyosarcoma (RMS) is a soft tissue sarcoma associated with the skeletal muscle lineage. Of the two predominant subtypes, known as embryonal (eRMS) and alveolar (aRMS), aRMS has the poorer prognosis, with a five-year survival rate of <50%. The majority of aRMS tumors express the fusion protein PAX3-FOXO1. As PAX3-FOXO1 has proven chemically intractable, this study aims to identify targetable proteins that are downstream from or cooperate with PAX3-FOXO1 to support tumorigenesis. Microarray analysis of the transcriptomes of human skeletal muscle myoblasts expressing PAX3-FOXO1 revealed alteration of several Wnt pathway gene members, including secreted frizzled related protein 3 (SFRP3), a secreted Wnt pathway inhibitor. Loss-of-function using shRNAs against SFRP3 was used to interrogate the role of SFRP3 in human aRMS cell lines in vitro and conditional murine xenograft systems in vivo. The combination of SFRP3 genetic suppression and the chemotherapeutic agent vincristine was also examined. In vitro, suppression of SFRP3 inhibited aRMS cell growth, reduced proliferation accompanied by a G1 arrest and induction of p21, and induced apoptosis. In vivo, doxycycline-inducible suppression of SFRP3 reduced aRMS tumor growth and weight by more than three-fold, in addition to increasing myogenic differentiation and β-catenin signaling. The combination of SFRP3 suppression and vincristine was more effective at reducing aRMS cell growth in vitro than either treatment alone, and ablated tumorigenesis in vivo. SFRP3 is necessary for the growth of human aRMS cells both in vitro and in vivo and is a promising new target for investigation in aRMS. ©2015 American Association for Cancer Research.

Arm to leg coordination in elite butterfly swimmers.

PubMed

Chollet, D; Seifert, L; Boulesteix, L; Carter, M

2006-04-01

This study proposed the use of four time gaps to assess arm-to-leg coordination in the butterfly stroke at increasing race paces. Fourteen elite male swimmers swam at four velocities corresponding to the appropriate paces for, respectively, the 400-m, 200-m, 100-m, and 50-m events. The different stroke phases of the arm and leg were identified by video analysis and then used to calculate four time gaps (T1: time gap between entry of the hands in the water and the high break-even point of the first undulation; T2: time gap between the beginning of the hands' backward movement and the low break-even point of the first undulation; T3: time gap between the hands' arrival in a vertical plane to the shoulders and the high break-even point of the second undulation; T4: time gap between the hands' release from the water and the low break-even point of the second undulation), the values of which described the changing relationship of arm to leg movements over an entire stroke cycle. With increases in pace, elite swimmers increased the stroke rate, the relative duration of the arm pull, the recovery and the first downward movement of the legs, and decreased the stroke length, the relative duration of the arm catch phase and the body glide with arms forward (measured by T2), until continuity in the propulsive actions was achieved. Whatever the paces, the T1, T3, and T4 values were close to zero and revealed a high degree of synchronisation at key motor points of the arm and leg actions. This new method to assess butterfly coordination could facilitate learning and coaching by situating the place of the leg undulation in relation with the arm stroke.

Non-paretic arm force does not over-inhibit the paretic arm in chronic post-stroke hemiparesis

PubMed Central

Dimyan, Michael A.; Perez, Monica A.; Auh, Sungyoung; Tarula, Erick; Wilson, Matthew; Cohen, Leonardo G.

2014-01-01

Objective To determine whether non-paretic arm force over-inhibits the paretic arm in patients with chronic unilateral post-stroke hemiparesis. We hypothesized that interhemispheric inhibition would increase more in healthy controls than in hemiparetic patients. Design Case-control neurophysiologic and behavioral study of patients with chronic stroke. Setting Federal research institution, outpatient clinical research setting Participants Eighty-six referred patients were screened to enroll 9 participants with greater than 6 month history of one unilateral ischemic infarct that resulted in arm hemiparesis, with residual ability to produce 1Nm of wrist flexion torque, without contraindication to transcranial magnetic stimulation. 8 age- and handedness-matched healthy volunteers without neurologic diagnosis were studied for comparison. Interventions Not Applicable Main Outcome Measures Change in interhemispheric inhibition targeting the ipsilesional primary-motor-cortex (M1) during non-paretic arm force. Results Healthy age-matched controls had significantly greater increases in inhibition from their active to resting M1 than did stroke patients from their active contralesional to resting ipsilesional M1 in the same scenario (20% ±7 vs. −1% ±4, F1,12=6.61, p=0.0245). Patients with greater increases in contralesional to ipsilesional inhibition were better performers on the nine-hole-peg-test of paretic arm function. Conclusions Our findings reveal that producing force with the non-paretic arm does not necessarily over-inhibit the paretic arm. Though limited in generalizability by the small sample size, we found that greater active contralesional to resting ipsilesional M1 inhibition was related to better recovery in this subset of chronic post-stroke patients. PMID:24440364

Arm Dominance Affects Feedforward Strategy more than Feedback Sensitivity during a Postural Task

PubMed Central

Walker, Elise H. E.; Perreault, Eric J.

2015-01-01

Handedness is a feature of human motor control that is still not fully understood. Recent work has demonstrated that the dominant and nondominant arm each excel at different behaviors, and has proposed that this behavioral asymmetry arises from lateralization in the cerebral cortex: the dominant side specializes in predictive trajectory control, while the nondominant side is specialized for impedance control. Long-latency stretch reflexes are an automatic mechanism for regulating posture, and have been shown to contribute to limb impedance. To determine whether long-latency reflexes also contribute to asymmetric motor behavior in the upper limbs, we investigated the effect of arm dominance on stretch reflexes during a postural task that required varying degrees of impedance control. Our results demonstrated slightly but significantly larger reflex responses in the biarticular muscles of the nondominant arm, as would be consistent with increased impedance control. These differences were attributed solely to higher levels of voluntary background activity in the nondominant biarticular muscles, indicating that feedforward strategies for postural stability may differ between arms. Reflex sensitivity, which was defined as the magnitude of the reflex response for matched levels of background activity, was not significantly different between arms for a broad subject population ranging from 23–51 years of age. These results indicate that inter-arm differences in feedforward strategies are more influential during posture than differences in feedback sensitivity, in a broad subject population. Interestingly, restricting our analysis to subjects under 40 years of age revealed a small increase in long-latency reflex sensitivity in the nondominant arm relative to the dominant arm. Though our subject numbers were small for this secondary analysis, it suggests that further studies may be required to assess the influence of reflex lateralization throughout development. PMID:25850407

Arm dominance affects feedforward strategy more than feedback sensitivity during a postural task.

PubMed

Walker, Elise H E; Perreault, Eric J

2015-07-01

Handedness is a feature of human motor control that is still not fully understood. Recent work has demonstrated that the dominant and nondominant arm each excel at different behaviors and has proposed that this behavioral asymmetry arises from lateralization in the cerebral cortex: the dominant side specializes in predictive trajectory control, while the nondominant side is specialized for impedance control. Long-latency stretch reflexes are an automatic mechanism for regulating posture and have been shown to contribute to limb impedance. To determine whether long-latency reflexes also contribute to asymmetric motor behavior in the upper limbs, we investigated the effect of arm dominance on stretch reflexes during a postural task that required varying degrees of impedance control. Our results demonstrated slightly but significantly larger reflex responses in the biarticular muscles of the nondominant arm, as would be consistent with increased impedance control. These differences were attributed solely to higher levels of voluntary background activity in the nondominant biarticular muscles, indicating that feedforward strategies for postural stability may differ between arms. Reflex sensitivity, which was defined as the magnitude of the reflex response for matched levels of background activity, was not significantly different between arms for a broad subject population ranging from 23 to 51 years of age. These results indicate that inter-arm differences in feedforward strategies are more influential during posture than differences in feedback sensitivity, in a broad subject population. Interestingly, restricting our analysis to subjects under 40 years of age revealed a small increase in long-latency reflex sensitivity in the nondominant arm relative to the dominant arm. Though our subject numbers were small for this secondary analysis, it suggests that further studies may be required to assess the influence of reflex lateralization throughout development.

Atomic oxygen reactor having at least one sidearm conduit

NASA Technical Reports Server (NTRS)

Koontz, Steven L. (Inventor)

1994-01-01

An apparatus for treating a microporous structure with atomic oxygen is presented. The apparatus includes a main gas chamber for flowing gas in an axial direction and a source of gas, containing atomic oxygen, connected for introducing the gas into the main gas chamber. The apparatus employs at least one side arm extending from the main atomic oxygen-containing chamber. The side arm has characteristic relaxation times such that a uniform atomic oxygen dose rate is delivered to a specimen positioned transversely in the side arm spaced from the main gas chamber.

Neurobiology: motor control of flexible octopus arms.

PubMed

Sumbre, Germán; Fiorito, Graziano; Flash, Tamar; Hochner, Binyamin

2005-02-10

Animals with rigid skeletons can rely on several mechanisms to simplify motor control--for example, they have skeletal joints that reduce the number of variables and degrees of freedom that need to be controlled. Here we show that when the octopus uses one of its long and highly flexible arms to transfer an object from one place to another, it employs a vertebrate-like strategy, temporarily reconfiguring its arm into a stiffened, articulated, quasi-jointed structure. This indicates that an articulated limb may provide an optimal solution for achieving precise, point-to-point movements.

KSC-03pd0075

NASA Image and Video Library

2003-01-15

KENNEDY SPACE CENTER, FLA. -- After rollback of the Rotating Service Structure on Launch Pad 39A, the top of Space Shuttle Columbia's external tank and solid rocket booster are bathed in sunlight. Shadows from the Fixed Service Structure stretch across the Shuttle and landscape. Visible are the orbiter access arm with the White Room extended to Columbia's cockpit, and at the top, the gaseous oxygen vent arm and cap, called the "beanie cap." Columbia is scheduled for launch Jan. 16 at 10:39 a.m. EST on mission STS-107, a research mission.

High speed precision motion strategies for lightweight structures

NASA Technical Reports Server (NTRS)

Book, Wayne J.

1987-01-01

Work during the recording period proceeded along the lines of the proposal, i.e., three aspects of high speed motion planning and control of flexible structures were explored: fine motion control, gross motion planning and control, and automation using light weight arms. In addition, modeling the large manipulator arm to be used in experiments and theory has lead to some contributions in that area. These aspects are reported below. Conference, workshop and journal submissions, and presentations related to this work were seven in number, and are listed. Copies of written papers and abstracts are included.

Structural model of dodecameric heat-shock protein Hsp21: Flexible N-terminal arms interact with client proteins while C-terminal tails maintain the dodecamer and chaperone activity.

PubMed

Rutsdottir, Gudrun; Härmark, Johan; Weide, Yoran; Hebert, Hans; Rasmussen, Morten I; Wernersson, Sven; Respondek, Michal; Akke, Mikael; Højrup, Peter; Koeck, Philip J B; Söderberg, Christopher A G; Emanuelsson, Cecilia

2017-05-12

Small heat-shock proteins (sHsps) prevent aggregation of thermosensitive client proteins in a first line of defense against cellular stress. The mechanisms by which they perform this function have been hard to define due to limited structural information; currently, there is only one high-resolution structure of a plant sHsp published, that of the cytosolic Hsp16.9. We took interest in Hsp21, a chloroplast-localized sHsp crucial for plant stress resistance, which has even longer N-terminal arms than Hsp16.9, with a functionally important and conserved methionine-rich motif. To provide a framework for investigating structure-function relationships of Hsp21 and understanding these sequence variations, we developed a structural model of Hsp21 based on homology modeling, cryo-EM, cross-linking mass spectrometry, NMR, and small-angle X-ray scattering. Our data suggest a dodecameric arrangement of two trimer-of-dimer discs stabilized by the C-terminal tails, possibly through tail-to-tail interactions between the discs, mediated through extended I X V X I motifs. Our model further suggests that six N-terminal arms are located on the outside of the dodecamer, accessible for interaction with client proteins, and distinct from previous undefined or inwardly facing arms. To test the importance of the I X V X I motif, we created the point mutant V181A, which, as expected, disrupts the Hsp21 dodecamer and decreases chaperone activity. Finally, our data emphasize that sHsp chaperone efficiency depends on oligomerization and that client interactions can occur both with and without oligomer dissociation. These results provide a generalizable workflow to explore sHsps, expand our understanding of sHsp structural motifs, and provide a testable Hsp21 structure model to inform future investigations. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Acute bilateral painless radiculitis with abnormal Borrelia burgdorferi immunoblot.

PubMed

Almodovar, Jorge L; Hehir, Michael K; Nicholson, Katharine A; Stommel, Elijah W

2012-12-01

A 57-year-old woman with a history of hypertension and hypothyroidism presented with painless left arm weakness and numbness 2 weeks before evaluation. Nerve conduction studies of the left arm revealed normal motor and sensory responses. Needle examination revealed acute denervation changes in all myotomes of the affected extremity, including cervical paraspinals on the left, and several myotomes on the contralateral side. The laboratory evaluation revealed normal anti-GM1 antibodies and 3 IgM/5 IgG bands on Lyme Western Blot. The patient began treatment with 28 days of intravenous ceftriaxone. On follow-up, patient had regained full strength of her extremities with no sensory deficits. Inflammatory borrelia radiculitis usually presents with pain in the distribution of the affected nerves and nerve roots. The novelty of this case report rests on (1) the absence of primary borreliosis symptomatology preceding the radiculitis and (2) the painless and bilateral clinical presentation in a patient with suspected Lyme radiculitis.

Flat H Redundant Frangible Joint Development

NASA Technical Reports Server (NTRS)

Brown, Chris

2016-01-01

Orion and Commercial Crew Program (CCP) Partners have chosen to use frangible joints for certain separation events. The joints currently available are zero failure tolerant and will be used in mission safety applications. The goal is to further develop a NASA designed redundant frangible joint that will lower flight risk and increase reliability. FY16 testing revealed a successful design in subscale straight test specimens that gained efficiency and supports Orion load requirements. Approach / Innovation A design constraint is that the redundant joint must fit within the current Orion architecture, without the need for additional vehicle modification. This limitation required a design that changed the orientation of the expanding tube assemblies (XTAs), by rotating them 90deg from the standard joint configuration. The change is not trivial and affects the fracture mechanism and structural load paths. To address these changes, the design incorporates cantilevered arms on the break plate. The shock transmission and expansion of the XTA applies force to these arms and creates a prying motion to push the plate walls outward to the point of structural failure at the notched section. The 2014 test design revealed that parts could slip during functioning wasting valuable energy needed to separate the structure with only a single XTA functioning. Dual XTA functioning fully separated the assembly showing a discrepancy can be backed up with redundancy. Work on other fully redundant systems outside NASA is limited to a few patents that have not been subjected to functionality testing Design changes to prevent unwanted slippage (with ICA funding in 2015) showed success with a single XTA. The main goal for FY 2016 was to send the new Flat H RFJ to WSTF where single XTA test failures occurred back in 2014. The plan was to gain efficiency in this design by separating the Flat H RFJ with thicker ligaments with dimensions baselined in 2014. Other modifications included geometry changes to better disperse loads paths and to minimize air gaps. The design additionally added more structural strength to enhance the structural limits in static loads testing. The design also implemented a smoother load line through the assembly. Results / Knowledge Gained The new Flat H RFJ successfully fractured at WSTF with thicker ligaments and lower cord size. Where failure to separate occurred earlier, there is now excessive energy available for structural separation. The new challenge to provide some structural support to prevent secondary fracturing of the break plate remains to be completed. This future work is being funded by the JSC Engineering Directorate in 2017 to elevate the TRL on curved Flat H RFJs that configure with the Orion Service Panel Separation. Additional funding from JSC Engineering will provide new design testing to avoid secondary fracturing.

Soft-sediment deformation produced by tides in a meizoseismic area, Turnagain Arm, Alaska

USGS Publications Warehouse

Greb, S.F.; Archer, A.W.

2007-01-01

Turnagain Arm is a semidiurnal hypertidal estuary in southeastern Alaska with a recorded tidal range of 9 m. Contorted bedding and flow rolls preserved in tidal sediments within the estuary have previously been interpreted as resulting from the Mw 9.2 Great Alaskan earthquake of 1964. Horizons of flow rolls between undeformed beds in sediments and rock strata have been used to infer ancient earthquakes in other areas. Although many types of soft-sediment deformation structures can be formed by earthquakes, observations of sedimentation on tidal flats in the inner parts of Turnagain Arm in the summers of 2003 and 2004 show that a wide range of soft-sediment deformation structures, similar to those inferred to have been formed by earthquakes, can form in macrotidal estuaries in the absence of seismic shock. During sedimentation rate measurements in 2004, soft-sediment deformation structures were recorded that formed during one day's tide, either in response to overpressurization of tidal flats during rapid tidal drawdown or by shear stress exerted on the bed by the passage of a 1.8 m tidal bore. Structures consisted of How rolls, dish structures, flames, and small dewatering pipes in a bed 17 cm thick. In the future, if the flow rolls in Turnagain Arm were found in isolated outcrops across an area 11 km in length, in an estuary known to have been influenced by large-magnitude earthquakes, would they be interpreted as seismites? These examples show that caution is needed when using horizons of flow rolls to infer paleoseismicity in estuarine deposits because many of the mechanisms (tidal flux, tidal bores, slumping, flooding) that can cause deformation in rapidly deposited, unconsolidated silts and sands, are orders of magnitude more common than great earthquakes. ?? 2007 The Geological Society of America.

Prolonged training does not result in a greater extent of interlimb transfer following visuomotor adaptation.

PubMed

Lei, Yuming; Wang, Jinsung

2014-11-01

Learning a visumotor adaptation task with one arm typically facilitates subsequent performance with the other. The extent of transfer across the arms, however, is generally much smaller than that across different conditions within the same arm. This may be attributed to a possibility that intralimb transfer involves both algorithmic and instance-reliant learning, whereas interlimb transfer only involves algorithmic learning. Here, we investigated whether prolonged training with one arm could facilitate subsequent performance with the other arm to a greater extent, by examining the effect of varying lengths of practice trials on the extent of interlimb transfer. We had 18 subjects adapt to a 30° visuomotor rotation with the left arm first (training), then with the right arm (transfer). During the training session, the subjects reached toward multiple targets for 160, 320 or 400 trials; during the transfer session, all subjects performed the same task for 160 trials. Our results revealed substantial initial transfer from the left to the right arm in all three conditions. However, neither the amount of initial transfer nor the rate of adaptation during the transfer session was significantly different across the conditions, indicating that the extent of transfer was similar regardless of the length of initial training. Our findings suggest that interlimb transfer of visuomotor adaptation may only occur through algorithmic learning, which is effector independent, and that prolonged training may only have beneficial effects when instance-reliant learning, which is effector dependent, is also involved in the learning process. Copyright © 2014 Elsevier Inc. All rights reserved.

Initial information prior to movement onset influences kinematics of upward arm pointing movements

PubMed Central

Pozzo, Thierry; White, Olivier

2016-01-01

To elaborate a motor plan and perform online control in the gravity field, the brain relies on priors and multisensory integration of information. In particular, afferent and efferent inputs related to the initial state are thought to convey sensorimotor information to plan the upcoming action. Yet it is still unclear to what extent these cues impact motor planning. Here we examined the role of initial information on the planning and execution of arm movements. Participants performed upward arm movements around the shoulder at three speeds and in two arm conditions. In the first condition, the arm was outstretched horizontally and required a significant muscular command to compensate for the gravitational shoulder torque before movement onset. In contrast, in the second condition the arm was passively maintained in the same position with a cushioned support and did not require any muscle contraction before movement execution. We quantified differences in motor performance by comparing shoulder velocity profiles. Previous studies showed that asymmetric velocity profiles reflect an optimal integration of the effects of gravity on upward movements. Consistent with this, we found decreased acceleration durations in both arm conditions. However, early differences in kinematic asymmetries and EMG patterns between the two conditions signaled a change of the motor plan. This different behavior carried on through trials when the arm was at rest before movement onset and may reveal a distinct motor strategy chosen in the context of uncertainty. Altogether, we suggest that the information available online must be complemented by accurate initial information. PMID:27486106

Initial information prior to movement onset influences kinematics of upward arm pointing movements.

PubMed

Rousseau, Célia; Papaxanthis, Charalambos; Gaveau, Jérémie; Pozzo, Thierry; White, Olivier

2016-10-01

To elaborate a motor plan and perform online control in the gravity field, the brain relies on priors and multisensory integration of information. In particular, afferent and efferent inputs related to the initial state are thought to convey sensorimotor information to plan the upcoming action. Yet it is still unclear to what extent these cues impact motor planning. Here we examined the role of initial information on the planning and execution of arm movements. Participants performed upward arm movements around the shoulder at three speeds and in two arm conditions. In the first condition, the arm was outstretched horizontally and required a significant muscular command to compensate for the gravitational shoulder torque before movement onset. In contrast, in the second condition the arm was passively maintained in the same position with a cushioned support and did not require any muscle contraction before movement execution. We quantified differences in motor performance by comparing shoulder velocity profiles. Previous studies showed that asymmetric velocity profiles reflect an optimal integration of the effects of gravity on upward movements. Consistent with this, we found decreased acceleration durations in both arm conditions. However, early differences in kinematic asymmetries and EMG patterns between the two conditions signaled a change of the motor plan. This different behavior carried on through trials when the arm was at rest before movement onset and may reveal a distinct motor strategy chosen in the context of uncertainty. Altogether, we suggest that the information available online must be complemented by accurate initial information. Copyright © 2016 the American Physiological Society.

Compact waveguide circular polarizer

DOEpatents

Tantawi, Sami G.

2016-08-16

A multi-port waveguide is provided having a rectangular waveguide that includes a Y-shape structure with first top arm having a first rectangular waveguide port, a second top arm with second rectangular waveguide port, and a base arm with a third rectangular waveguide port for supporting a TE.sub.10 mode and a TE.sub.20 mode, where the end of the third rectangular waveguide port includes rounded edges that are parallel to a z-axis of the waveguide, a circular waveguide having a circular waveguide port for supporting a left hand and a right hand circular polarization TE.sub.11 mode and is coupled to a base arm broad wall, and a matching feature disposed on the base arm broad wall opposite of the circular waveguide for terminating the third rectangular waveguide port, where the first rectangular waveguide port, the second rectangular waveguide port and the circular waveguide port are capable of supporting 4-modes of operation.

OT2_tvelusam_4: Probing Galactic Spiral Arm Tangencies with [CII

NASA Astrophysics Data System (ADS)

Velusamy, T.

2011-09-01

We propose to use the unique viewing geometry of the Galactic spiral arm tangents , which provide an ideal environment for studying the effects of density waves on spiral structure. We propose a well-sampled map of the[C II] 1.9 THz line emission along a 15-degree longitude region across the Norma-3kpc arm tangential, which includes the edge of the Perseus Arm. The COBE-FIRAS instrument observed the strongest [C II] and [N II] emission along these spiral arm tangencies.. The Herschel Open Time Key Project Galactic Observations of Terahertz C+ (GOT C+), also detects the strongest [CII] emission near these spiral arm tangential directions in its sparsely sampled HIFI survey of [CII] in the Galactic plane survey. The [C II] 158-micron line is the strongest infrared line emitted by the ISM and is an excellent tracer and probe of both the diffuse gases in the cold neutral medium (CNM) and the warm ionized medium (WIM). Furthermore, as demonstrated in the GOTC+ results, [C II] is an efficient tracer of the dark H2 gas in the ISM that is not traced by CO or HI observations. Thus, taking advantage of the long path lengths through the spiral arm across the tangencies, we can use the [C II] emission to trace and characterize the diffuse atomic and ionized gas as well as the diffuse H2 molecular gas in cloud transitions from HI to H2 and C+ to C and CO, throughout the ISM. The main goal of our proposal is to use the well sampled (at arcmin scale) [C II] to study these gas components of the ISM in the spiral-arm, and inter-arm regions, to constrain models of the spiral structure and to understand the influence of spiral density waves on the Galactic gas and the dynamical interaction between the different components. The proposed HIFI observations will consist of OTF 15 degree longitude scans and one 2-degree latitude scan sampled every 40arcsec across the Norma- 3kpc Perseus Spiral tangency.

Experiments in thrusterless robot locomotion control for space applications. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Jasper, Warren Joseph

1990-01-01

While performing complex assembly tasks or moving about in space, a space robot should minimize the amount of propellant consumed. A study is presented of space robot locomotion and orientation without the use of thrusters. The goal was to design a robot control paradigm that will perform thrusterless locomotion between two points on a structure, and to implement this paradigm on an experimental robot. A two arm free flying robot was constructed which floats on a cushion of air to simulate in 2-D the drag free, zero-g environment of space. The robot can impart momentum to itself by pushing off from an external structure in a coordinated two arm maneuver, and can then reorient itself by activating a momentum wheel. The controller design consists of two parts: a high level strategic controller and a low level dynamic controller. The control paradigm was verified experimentally by commanding the robot to push off from a structure with both arms, rotate 180 degs while translating freely, and then to catch itself on another structure. This method, based on the computed torque, provides a linear feedback law in momentum and its derivatives for a system of rigid bodies.

The simulation of molecular clouds formation in the Milky Way

NASA Astrophysics Data System (ADS)

Khoperskov, S. A.; Vasiliev, E. O.; Sobolev, A. M.; Khoperskov, A. V.

2013-01-01

Using 3D hydrodynamic calculations we simulate formation of molecular clouds in the Galaxy. The simulations take into account molecular hydrogen chemical kinetics, cooling and heating processes. Comprehensive gravitational potential accounts for contributions from the stellar bulge, two- and four-armed spiral structure, stellar disc, dark halo and takes into account self-gravitation of the gaseous component. Gas clouds in our model form in the spiral arms due to shear and wiggle instabilities and turn into molecular clouds after t ≳ 100 Myr. At the times t ˜ 100-300 Myr the clouds form hierarchical structures and agglomerations with the sizes of 100 pc and greater. We analyse physical properties of the simulated clouds and find that synthetic statistical distributions like mass spectrum, `mass-size' relation and velocity dispersion are close to those observed in the Galaxy. The synthetic l-v (galactic longitude-radial velocity) diagram of the simulated molecular gas distribution resembles observed one and displays a structure with appearance similar to molecular ring of the Galaxy. Existence of this structure in our modelling can be explained by superposition of emission from the galactic bar and the spiral arms at ˜3-4 kpc.

Mental health service acceptability for the armed forces veteran community.

PubMed

Farrand, P; Jeffs, A; Bloomfield, T; Greenberg, N; Watkins, E; Mullan, E

2018-06-15

Despite developments in mental health services for armed forces veterans and family members, barriers to access associated with poor levels of acceptability regarding service provision remain. Adapting a Step 2 mental health service based on low-intensity cognitive behavioural therapy (CBT) interventions to represent a familiar context and meet the needs of the armed forces veteran community may serve to enhance acceptability and reduce help-seeking barriers. To examine acceptability of a Step 2 low-intensity CBT mental health service adapted for armed forces veterans and family members provided by a UK Armed Forces charity. Qualitative study using individual semi-structured interviews with armed forces veterans and family members of those injured or becoming unwell while serving in the British Armed Forces. Data analysis was undertaken using thematic alongside disconfirming case analysis. Adapting a Step 2 mental health service for armed forces veterans and family members enhanced acceptability and promoted help-seeking. Wider delivery characteristics associated with Step 2 mental health services within the Improving Access to Psychological Therapies (IAPT) programme also contributed to service acceptability. However, limitations of Step 2 mental health service provision were also identified. A Step 2 mental health service adapted for armed forces veterans and family members enhances acceptability and may potentially overcome help-seeking barriers. However, concerns remain regarding ways to accommodate the treatment of post-traumatic stress disorder and provide support for family members.

Kinematic decomposition and classification of octopus arm movements.

PubMed

Zelman, Ido; Titon, Myriam; Yekutieli, Yoram; Hanassy, Shlomi; Hochner, Binyamin; Flash, Tamar

2013-01-01

The octopus arm is a muscular hydrostat and due to its deformable and highly flexible structure it is capable of a rich repertoire of motor behaviors. Its motor control system uses planning principles and control strategies unique to muscular hydrostats. We previously reconstructed a data set of octopus arm movements from records of natural movements using a sequence of 3D curves describing the virtual backbone of arm configurations. Here we describe a novel representation of octopus arm movements in which a movement is characterized by a pair of surfaces that represent the curvature and torsion values of points along the arm as a function of time. This representation allowed us to explore whether the movements are built up of elementary kinematic units by decomposing each surface into a weighted combination of 2D Gaussian functions. The resulting Gaussian functions can be considered as motion primitives at the kinematic level of octopus arm movements. These can be used to examine underlying principles of movement generation. Here we used combination of such kinematic primitives to decompose different octopus arm movements and characterize several movement prototypes according to their composition. The representation and methodology can be applied to the movement of any organ which can be modeled by means of a continuous 3D curve.

Kinematic decomposition and classification of octopus arm movements

PubMed Central

Zelman, Ido; Titon, Myriam; Yekutieli, Yoram; Hanassy, Shlomi; Hochner, Binyamin; Flash, Tamar

2013-01-01

The octopus arm is a muscular hydrostat and due to its deformable and highly flexible structure it is capable of a rich repertoire of motor behaviors. Its motor control system uses planning principles and control strategies unique to muscular hydrostats. We previously reconstructed a data set of octopus arm movements from records of natural movements using a sequence of 3D curves describing the virtual backbone of arm configurations. Here we describe a novel representation of octopus arm movements in which a movement is characterized by a pair of surfaces that represent the curvature and torsion values of points along the arm as a function of time. This representation allowed us to explore whether the movements are built up of elementary kinematic units by decomposing each surface into a weighted combination of 2D Gaussian functions. The resulting Gaussian functions can be considered as motion primitives at the kinematic level of octopus arm movements. These can be used to examine underlying principles of movement generation. Here we used combination of such kinematic primitives to decompose different octopus arm movements and characterize several movement prototypes according to their composition. The representation and methodology can be applied to the movement of any organ which can be modeled by means of a continuous 3D curve. PMID:23745113

Agonist-Specific Recruitment of Arrestin Isoforms Differentially Modify Delta Opioid Receptor Function

PubMed Central

Perroy, Julie; Walwyn, Wendy M.; Smith, Monique L.; Vicente-Sanchez, Ana; Segura, Laura; Bana, Alia; Kieffer, Brigitte L.; Evans, Christopher J.

2016-01-01

Ligand-specific recruitment of arrestins facilitates functional selectivity of G-protein-coupled receptor signaling. Here, we describe agonist-selective recruitment of different arrestin isoforms to the delta opioid receptor in mice. A high-internalizing delta opioid receptor agonist (SNC80) preferentially recruited arrestin 2 and, in arrestin 2 knock-outs (KOs), we observed a significant increase in the potency of SNC80 to inhibit mechanical hyperalgesia and decreased acute tolerance. In contrast, the low-internalizing delta agonists (ARM390, JNJ20788560) preferentially recruited arrestin 3 with unaltered behavioral effects in arrestin 2 KOs. Surprisingly, arrestin 3 KO revealed an acute tolerance to these low-internalizing agonists, an effect never observed in wild-type animals. Furthermore, we examined delta opioid receptor–Ca2+ channel coupling in dorsal root ganglia desensitized by ARM390 and the rate of resensitization was correspondingly decreased in arrestin 3 KOs. Live-cell imaging in HEK293 cells revealed that delta opioid receptors are in pre-engaged complexes with arrestin 3 at the cell membrane and that ARM390 strengthens this membrane interaction. The disruption of these complexes in arrestin 3 KOs likely accounts for the altered responses to low-internalizing agonists. Together, our results show agonist-selective recruitment of arrestin isoforms and reveal a novel endogenous role of arrestin 3 as a facilitator of resensitization and an inhibitor of tolerance mechanisms. SIGNIFICANCE STATEMENT Agonists that bind to the same receptor can produce highly distinct signaling events and arrestins are a major mediator of this ligand bias. Here, we demonstrate that delta opioid receptor agonists differentially recruit arrestin isoforms. We found that the high-internalizing agonist SNC80 preferentially recruits arrestin 2 and knock-out (KO) of this protein results in increased efficacy of SNC80. In contrast, low-internalizing agonists (ARM390 and JNJ20788560) preferentially recruit arrestin 3 and, surprisingly, KO of arrestin 3 produces acute tolerance and impaired receptor resensitization to these agonists. Arrestin 3 is in pre-engaged complexes with the delta opioid receptor at the cell membrane and low-internalizing agonists promote this interaction. This study reveals a novel role for arrestin 3 as a facilitator of receptor resensitization. PMID:27013682

Altered gene regulation and synaptic morphology in Drosophila learning and memory mutants

PubMed Central

Guan, Zhuo; Buhl, Lauren K.; Quinn, William G.; Littleton, J. Troy

2011-01-01

Genetic studies in Drosophila have revealed two separable long-term memory pathways defined as anesthesia-resistant memory (ARM) and long-lasting long-term memory (LLTM). ARM is disrupted in radish (rsh) mutants, whereas LLTM requires CREB-dependent protein synthesis. Although the downstream effectors of ARM and LLTM are distinct, pathways leading to these forms of memory may share the cAMP cascade critical for associative learning. Dunce, which encodes a cAMP-specific phosphodiesterase, and rutabaga, which encodes an adenylyl cyclase, both disrupt short-term memory. Amnesiac encodes a pituitary adenylyl cyclase-activating peptide homolog and is required for middle-term memory. Here, we demonstrate that the Radish protein localizes to the cytoplasm and nucleus and is a PKA phosphorylation target in vitro. To characterize how these plasticity pathways may manifest at the synaptic level, we assayed synaptic connectivity and performed an expression analysis to detect altered transcriptional networks in rutabaga, dunce, amnesiac, and radish mutants. All four mutants disrupt specific aspects of synaptic connectivity at larval neuromuscular junctions (NMJs). Genome-wide DNA microarray analysis revealed ∼375 transcripts that are altered in these mutants, suggesting defects in multiple neuronal signaling pathways. In particular, the transcriptional target Lapsyn, which encodes a leucine-rich repeat cell adhesion protein, localizes to synapses and regulates synaptic growth. This analysis provides insights into the Radish-dependent ARM pathway and novel transcriptional targets that may contribute to memory processing in Drosophila. PMID:21422168

Fingerprints of nucleosynthesis in the local spiral arm

NASA Technical Reports Server (NTRS)

Knoedlseder, J.; Bennett, K.; Bloemen, H.; Diehl, R.; Hermsen, W.; Oberlack, U.; Ryan, J.; Schoenfelder, V.; vonBallmoos, P.

1997-01-01

The local spiral arm with its inherent massive star population is a natural site of recent nucleosynthesis activity. The features found in 1.8 MeV observation of candidate Al-26 sources situated in this structure are discussed. The emphasis is on Loop 1, a nearby superbubble which is possibly the site of a recent supernova explosion.

Cell elongation is an adaptive response for clearing long chromatid arms from the cleavage plane

PubMed Central

Kotadia, Shaila; Montembault, Emilie; Sullivan, William

2012-01-01

Chromosome segregation must be coordinated with cell cleavage to ensure correct transmission of the genome to daughter cells. Here we identify a novel mechanism by which Drosophila melanogaster neuronal stem cells coordinate sister chromatid segregation with cleavage furrow ingression. Cells adapted to a dramatic increase in chromatid arm length by transiently elongating during anaphase/telophase. The degree of cell elongation correlated with the length of the trailing chromatid arms and was concomitant with a slight increase in spindle length and an enlargement of the zone of cortical myosin distribution. Rho guanine-nucleotide exchange factor (Pebble)–depleted cells failed to elongate during segregation of long chromatids. As a result, Pebble-depleted adult flies exhibited morphological defects likely caused by cell death during development. These studies reveal a novel pathway linking trailing chromatid arms and cortical myosin that ensures the clearance of chromatids from the cleavage plane at the appropriate time during cytokinesis, thus preserving genome integrity. PMID:23185030

KSC-06pd0479

NASA Image and Video Library

2006-03-14

KENNEDY SPACE CENTER, FLA. - Inside the Orbiter Processing Facility bay 3 at NASA's Kennedy Space Center, workers attach an overhead crane to Discovery's robotic arm in the payload bay. The arm is being removed due to damage found on the arm after it was accidentally bumped by a bridge bucket in the payload bay. Ultrasound inspections revealed a small crack, measuring 1.25 inches by 0.015 inch deep. The arm will be sent back to the vendor for repair. The bucket was being used by technicians cleaning the area and was in the process of being stowed. A bridge bucket is a personnel transport device that is suspended from an overhead bridge that moves back and forth above the shuttle's mid-body. It allows workers to access the payload bay area without walking or standing on the payload bay floor or on the fixed platforms. Space Shuttle Discovery is scheduled for launch on mission STS-121 during a launch planning window of July 1-19. Photo credit: NASA/Kim Shiflett

Giant molecular filaments in the Milky Way. II. The fourth Galactic quadrant

NASA Astrophysics Data System (ADS)

Abreu-Vicente, J.; Ragan, S.; Kainulainen, J.; Henning, Th.; Beuther, H.; Johnston, K.

2016-05-01

Context. Filamentary structures are common morphological features of the cold, molecular interstellar medium (ISM). Recent studies have discovered massive, hundred-parsec-scale filaments that may be connected to the large-scale, Galactic spiral arm structure. Addressing the nature of these giant molecular filaments (GMFs) requires a census of their occurrence and properties. Aims: We perform a systematic search of GMFs in the fourth Galactic quadrant and determine their basic physical properties. Methods: We identify GMFs based on their dust extinction signatures in the near- and mid-infrared and the velocity structure probed by 13CO line emission. We use the 13CO line emission and ATLASGAL dust emission data to estimate the total and dense gas masses of the GMFs. We combine our sample with an earlier sample from literature and study the Galactic environment of the GMFs. Results: We identify nine GMFs in the fourth Galactic quadrant: six in the Centaurus spiral arm and three in inter-arm regions. Combining this sample with an earlier study using the same identification criteria in the first Galactic quadrant results in 16 GMFs, nine of which are located within spiral arms. The GMFs have sizes of 80-160 pc and 13CO-derived masses between 5-90 × 104M⊙. Their dense gas mass fractions are between 1.5-37%, which is higher in the GMFs connected to spiral arms. We also compare the different GMF-identification methods and find that emission and extinction-based techniques overlap only partially, thereby highlighting the need to use both to achieve a complete census. Table A.2 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/590/A131

Geometric Aspects and Testing of the Galactic Center Distance Determination from Spiral Arm Segments

NASA Astrophysics Data System (ADS)

Nikiforov, I. I.; Veselova, A. V.

2018-02-01

We consider the problem of determining the geometric parameters of a Galactic spiral arm from its segment by including the distance to the spiral pole, i.e., the distance to the Galactic center ( R 0). The question about the number of points belonging to one turn of a logarithmic spiral and defining this spiral as a geometric figure has been investigated numerically and analytically by assuming the direction to the spiral pole (to the Galactic center) to be known. Based on the results obtained, in an effort to test the new approach, we have constructed a simplified method of solving the problem that consists in finding the median of the values for each parameter from all possible triplets of objects in the spiral arm segment satisfying the condition for the angular distance between objects. Applying the method to the data on the spatial distribution of masers in the Perseus and Scutum arms (the catalogue by Reid et al. (2014)) has led to an estimate of R 0 = 8.8 ± 0.5 kpc. The parameters of five spiral arm segments have been determined from masers of the same catalogue. We have confirmed the difference between the spiral arms in pitch angle. The pitch angles of the arms revealed by masers are shown to generally correlate with R 0 in the sense that an increase in R 0 leads to a growth in the absolute values of the pitch angles.

Human arm stiffness and equilibrium-point trajectory during multi-joint movement.

PubMed

Gomi, H; Kawato, M

1997-03-01

By using a newly designed high-performance manipulandum and a new estimation algorithm, we measured human multi-joint arm stiffness parameters during multi-joint point-to-point movements on a horizontal plane. This manipulandum allows us to apply a sufficient perturbation to subject's arm within a brief period during movement. Arm stiffness parameters were reliably estimated using a new algorithm, in which all unknown structural parameters could be estimated independent of arm posture (i.e., constant values under any arm posture). Arm stiffness during transverse movement was considerably greater than that during corresponding posture, but not during a longitudinal movement. Although the ratios of elbow, shoulder, and double-joint stiffness were varied in time, the orientation of stiffness ellipses during the movement did not change much. Equilibrium-point trajectories that were predicted from measured stiffness parameters and actual trajectories were slightly sinusoidally curved in Cartesian space and their velocity profiles were quite different from the velocity profiles of actual hand trajectories. This result contradicts the hypothesis that the brain does not take the dynamics into account in movement control depending on the neuromuscular servo mechanism; rather, it implies that the brain needs to acquire some internal models of controlled objects.

Structures of the SER/THR linked variant oligosaccharides present in equine chorionic gonadotropin (eCG). beta. -subunit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bahl, O.P.; Anumula, K.R.

1986-05-01

eCG ..beta..-subunit contains more than 50% carbohydrate and constitutes about 72% of the hormone. O-linked carbohydrate (85%) was separated from the N-linked (15%) by gel filtration of the endoproteinase Lys-C digest. Six O-linked carbohydrate units were released by NaOH/NaB/sup 3/H/sub 4/ treatment. Oligosaccharides were fractionated by gel filtration and paper chromatography. Several oligosaccharides were obtained ranging in size from a sialyl di-saccharide to megalosaccharide with about 50 sugar residues. Methylation analyses and tlc examination of the oligosaccharides after endo- and exoglycosidase digestions and nitrous acid deamination and Smith degradation revealed a core structure of Gal..beta..1-4 GlcNAc..beta..1-6 (Gal ..beta..1-3) GalNAcH/sub 2/more » with poly-N-acetyllactosamine peripheral extensions. Nearly 50% of the oligosaccharides were large and were preferentially extended on 1,6 arm of the GalNAcH/sub 2/ by repeating N-acetyllactosamine units. Furthermore, these oligosaccharides contained branching 1,3,6-linked galactoses giving rise to tri, penta and multiantennary structures.« less

Ultra-thin ZnSe: Anisotropic and flexible crystal structure

NASA Astrophysics Data System (ADS)

Bacaksiz, C.; Senger, R. T.; Sahin, H.

2017-07-01

By performing density functional theory-based calculations, we investigate the structural, electronic, and mechanical properties of the thinnest ever ZnSe crystal [11]. The vibrational spectrum analysis reveals that the monolayer ZnSe is dynamically stable and has flexible nature with its soft phonon modes. In addition, a direct electronic band gap is found at the gamma point for the monolayer structure of ZnSe. We also elucidate that the monolayer ZnSe has angle dependent in-plane elastic parameters. In particular, the in-plane stiffness values are found to be 2.07 and 6.89 N/m for the arm-chair and zig-zag directions, respectively. The angle dependency is also valid for the Poisson ratio of the monolayer ZnSe. More significantly, the in-plane stiffness of the monolayer ZnSe is the one-tenth of Young modulus of bulk zb-ZnSe which indicates that the monolayer ZnSe is a quite flexible single layer crystal. With its flexible nature and in-plane anisotropic mechanical properties, the monolayer ZnSe is a good candidate for nanoscale mechanical applications.

Design and pilot validation of A-gear: a novel wearable dynamic arm support.

PubMed

Kooren, Peter N; Dunning, Alje G; Janssen, Mariska M H P; Lobo-Prat, Joan; Koopman, Bart F J M; Paalman, Micha I; de Groot, Imelda J M; Herder, Just L

2015-09-18

Persons suffering from progressive muscular weakness, like those with Duchenne muscular dystrophy (DMD), gradually lose the ability to stand, walk and to use their arms. This hinders them from performing daily activities, social participation and being independent. Wheelchairs are used to overcome the loss of walking. However, there are currently few efficient functional substitutes to support the arms. Arm supports or robotic arms can be mounted to wheelchairs to aid in arm motion, but they are quite visible (stigmatizing), and limited in their possibilities due to their fixation to the wheelchair. The users prefer inconspicuous arm supports that are comfortable to wear and easy to control. In this paper the design, characterization, and pilot validation of a passive arm support prototype, which is worn on the body, is presented. The A-gear runs along the body from the contact surface between seat and upper legs via torso and upper arm to the forearm. Freedom of motion is accomplished by mechanical joints, which are nearly aligned with the human joints. The system compensates for the arm weight, using elastic bands for static balance, in every position of the arm. As opposed to existing devices, the proposed kinematic structure allows trunk motion and requires fewer links and less joint space without compromising balancing precision. The functional prototype has been validated in three DMD patients, using 3D motion analysis. Measurements have shown increased arm performance when the subjects were wearing the prototype. Upward and forward movements were easier to perform. The arm support is easy to put on and remove. Moreover, the device felt comfortable for the subjects. However, downward movements were more difficult, and the patients would prefer the device to be even more inconspicuous. The A-gear prototype is a step towards inconspicuousness and therefore well-received dynamic arm supports for people with muscular weakness.

ATOMIC RESOLUTION CRYO ELECTRON MICROSCOPY OF MACROMOLECULAR COMPLEXES

PubMed Central

ZHOU, Z. HONG

2013-01-01

Single-particle cryo electron microscopy (cryoEM) is a technique for determining three-dimensional (3D) structures from projection images of molecular complexes preserved in their “native,” noncrystalline state. Recently, atomic or near-atomic resolution structures of several viruses and protein assemblies have been determined by single-particle cryoEM, allowing ab initio atomic model building by following the amino acid side chains or nucleic acid bases identifiable in their cryoEM density maps. In particular, these cryoEM structures have revealed extended arms contributing to molecular interactions that are otherwise not resolved by the conventional structural method of X-ray crystallography at similar resolutions. High-resolution cryoEM requires careful consideration of a number of factors, including proper sample preparation to ensure structural homogeneity, optimal configuration of electron imaging conditions to record high-resolution cryoEM images, accurate determination of image parameters to correct image distortions, efficient refinement and computation to reconstruct a 3D density map, and finally appropriate choice of modeling tools to construct atomic models for functional interpretation. This progress illustrates the power of cryoEM and ushers it into the arsenal of structural biology, alongside conventional techniques of X-ray crystallography and NMR, as a major tool (and sometimes the preferred one) for the studies of molecular interactions in supramolecular assemblies or machines. PMID:21501817

Uncovering the origins of spiral structure through the measurement of pattern speeds and their radial variation

NASA Astrophysics Data System (ADS)

Meidt, Sharon E.

At the intersection of galactic dynamics, evolution and global structure, unresolved issues in the nature and origin of spirals can be addressed through the characterization of the angular speeds of the patterns and their possible radial variation. In this thesis I describe the development, testing, and application of the Radial Tremaine-Weinberg (TWR) Method, a generalized version of the continuity-based TW method wherein the pattern speed is allowed to vary arbitrarily with radius. I will address the utility of, and caveats in applying, the TWR calculation together with a standard regularization technique in a series of tests on N- body simulations. The regularization, which smooths otherwise intrinsically noisy solutions based on a priori assumptions for the radial dependence of the pattern speed, proves to be essential for achieving the radial precision necessary for accurate measurement. I also present results from applications of the TWR method to observations of real galaxies, where the possible sources and sinks in the continuity equation are well understood. Using CO observations of the grand design galaxy M51, the TWR method reveals a heretofore un-measured inner spiral pattern speed for the bright two-armed spiral structure, with a value significantly higher than conventional estimates. In addition, the radial dependence implied in the TWR solution suggests a possible resonant link between the inner and outer regions of the bright spiral arms. These findings signify an advance in observational investigations into the nature and origin of grand-design spiral structure. By analyzing high-quality HI and CO data cubes available for four other spiral galaxies, the characteristic signatures of the processes that drive spiral structure are likewise identifiable; within this small sample, the first direct evidence for the presence of resonant coupling of multiple distinct patterns is found in some galaxies, while a simple single pattern speed is measured in others. I conclude with a summary of future avenues for investigation with the TWR method and propose additional modifications of the TW calculation with which the influence of bar and spiral structure on the evolution of galaxy disks can be directly characterized.

Anti-EGFR targeted therapy delivered before versus during radiotherapy in locoregionally advanced nasopharyngeal carcinoma: a big-data, intelligence platform-based analysis.

PubMed

Peng, Hao; Tang, Ling-Long; Liu, Xu; Chen, Lei; Li, Wen-Fei; Mao, Yan-Ping; Zhang, Yuan; Liu, Li-Zhi; Tian, Li; Guo, Ying; Sun, Ying; Ma, Jun

2018-03-27

Little is known about the prognostic difference of anti-EGFR therapy, cetuximab (CTX) or nimotuzumab (NTZ), concurrently with induction chemotherapy (IC, investigational arm) or RT (control arm) for patients with locoregionally advanced nasopharyngeal carcinoma (LA-NPC). We conducted this retrospective study to address this. We identified 296 patients with newly diagnosed LA-NPC at Sun Yat-Sen University Cancer Center between January 2012 and May 2015. Patients were treated by IC with CCRT or RT and CTX/NTZ was delivered during IC or radiotherapy. Survival outcomes and toxicities between different arms were compared. In total, there were 149 patients in the investigational arm and 147 in control arm. The 3-year disease-free survival, overall survival, distant metastasis-free survival and locoregional relapse-free survival rates for investigational arm vs. control arm were 84.3% vs. 74.3% (P = 0.027), 94.0% vs. 92.1% (P = 0.673), 88.0% vs. 81.8% (P = 0.147) and 93.3% vs. 88.0% (P = 0.093). Multivariate analysis revealed patients in the control arm achieved significantly worse disease-free survival (HR, 1.497; 95% CI, 1.016-2.206; P = 0.026) compared with those in the investigational arm; however, no significant difference was identified for other endpoints. Patients in the investigational arm experienced more grade 3-4 skin reaction (15.4% vs. 2.0%, P <  0.001) and mucositis (10.1% vs. 3.4%, P = 0.022) during induction phase, but less skin reaction (5.4% vs. 25.9%, P <  0.001) and mucositis (24.8% vs. 36.7%, P = 0.026) during RT. Our findings suggested that CTX/NTZ concurrently with IC may be a more effective and promising strategy for patients with LA-NPC receiving intensity-modulated radiotherapy.

Shadows cast on the transition disk of HD 135344B. Multiwavelength VLT/SPHERE polarimetric differential imaging

NASA Astrophysics Data System (ADS)

Stolker, T.; Dominik, C.; Avenhaus, H.; Min, M.; de Boer, J.; Ginski, C.; Schmid, H. M.; Juhasz, A.; Bazzon, A.; Waters, L. B. F. M.; Garufi, A.; Augereau, J.-C.; Benisty, M.; Boccaletti, A.; Henning, Th.; Langlois, M.; Maire, A.-L.; Ménard, F.; Meyer, M. R.; Pinte, C.; Quanz, S. P.; Thalmann, C.; Beuzit, J.-L.; Carbillet, M.; Costille, A.; Dohlen, K.; Feldt, M.; Gisler, D.; Mouillet, D.; Pavlov, A.; Perret, D.; Petit, C.; Pragt, J.; Rochat, S.; Roelfsema, R.; Salasnich, B.; Soenke, C.; Wildi, F.

2016-11-01

Context. The protoplanetary disk around the F-type star HD 135344B (SAO 206462) is in a transition stage and shows many intriguing structures both in scattered light and thermal (sub-)millimeter emission which are possibly related to planet formation processes. Aims: We aim to study the morphology and surface brightness of the disk in scattered light to gain insight into the innermost disk regions, the formation of protoplanets, planet-disk interactions traced in the surface and midplane layers, and the dust grain properties of the disk surface. Methods: We have carried out high-contrast polarimetric differential imaging (PDI) observations with VLT/SPHERE and obtained polarized scattered light images with ZIMPOL in the R and I-bands and with IRDIS in the Y and J-bands. The scattered light images and surface brightness profiles are used to study in detail structures in the disk surface and brightness variations. We have constructed a 3D radiative transfer model to support the interpretation of several detected shadow features. Results: The scattered light images reveal with unprecedented angular resolution and sensitivity the spiral arms as well as the 25 au cavity of the disk. Multiple shadow features are discovered on the outer disk with one shadow only being present during the second observation epoch. A positive surface brightness gradient is observed in the stellar irradiation corrected (r2-scaled) images in southwest direction possibly due to an azimuthally asymmetric perturbation of the temperature and/or surface density by the passing spiral arms. The disk integrated polarized flux, normalized to the stellar flux, shows a positive trend towards longer wavelengths which we attribute to large (2πa ≳ λ) aggregate dust grains in the disk surface. Part of the non-azimuthal polarization signal in the Uφ image of the J-band observation can be attributed to multiple scattering in the disk. Conclusions: The detected shadow features and their possible variability have the potential to provide insight into the structure of and processes occurring in the innermost disk regions. Possible explanations for the presence of the shadows include a 22° misaligned inner disk, a warped disk region that connects the inner disk with the outer disk, and variable or transient phenomena such as a perturbation of the inner disk or an asymmetric accretion flow. The spiral arms are best explained by one or multiple protoplanets in the exterior of the disk although no gap is detected beyond the spiral arms up to 1.''0. Based on observations collected at the European Southern Observatory, Chile, ESO No. 095.C-0273(A) and 095.C-0273(D).

Stereotypical reaching movements of the octopus involve both bend propagation and arm elongation.

PubMed

Hanassy, S; Botvinnik, A; Flash, T; Hochner, B

2015-05-13

The bend propagation involved in the stereotypical reaching movement of the octopus arm has been extensively studied. While these studies have analyzed the kinematics of bend propagation along the arm during its extension, possible length changes have been ignored. Here, the elongation profiles of the reaching movements of Octopus vulgaris were assessed using three-dimensional reconstructions. The analysis revealed that, in addition to bend propagation, arm extension movements involve elongation of the proximal part of the arm, i.e., the section from the base of the arm to the propagating bend. The elongations are quite substantial and highly variable, ranging from an average strain along the arm of -0.12 (i.e. shortening) up to 1.8 at the end of the movement (0.57 ± 0.41, n = 64 movements, four animals). Less variability was discovered in an additional set of experiments on reaching movements (0.64 ± 0.28, n = 30 movements, two animals), where target and octopus positions were kept more stationary. Visual observation and subsequent kinematic analysis suggest that the reaching movements can be broadly segregated into two groups. The first group involves bend propagation beginning at the base of the arm and propagating towards the arm tip. In the second, the bend is formed or present more distally and reaching is achieved mainly by elongation and straightening of the segment proximal to the bend. Only in the second type of movements is elongation significantly positively correlated with the distance of the bend from the target. We suggest that reaching towards a target is generated by a combination of both propagation of a bend along the arm and arm elongation. These two motor primitives may be combined to create a broad spectrum of reaching movements. The dynamical model, which recapitulates the biomechanics of the octopus muscular hydrostatic arm, suggests that achieving the observed elongation requires an extremely low ratio of longitudinal to transverse muscle force (<0.0016 for an average strain along the arm of around 0.5). This was not observed and moreover such extremely low value does not seem to be physiologically possible. Hence the assumptions made in applying the dynamic model to behaviors such as static arm stiffening that leads to arm extension through bend propagation and the patterns of activation used to simulate such behaviors should be modified to account for movements combining bend propagation and arm elongation.

A human body model for efficient numerical characterization of UWB signal propagation in wireless body area networks.

PubMed

Lim, Hooi Been; Baumann, Dirk; Li, Er-Ping

2011-03-01

Wireless body area network (WBAN) is a new enabling system with promising applications in areas such as remote health monitoring and interpersonal communication. Reliable and optimum design of a WBAN system relies on a good understanding and in-depth studies of the wave propagation around a human body. However, the human body is a very complex structure and is computationally demanding to model. This paper aims to investigate the effects of the numerical model's structure complexity and feature details on the simulation results. Depending on the application, a simplified numerical model that meets desired simulation accuracy can be employed for efficient simulations. Measurements of ultra wideband (UWB) signal propagation along a human arm are performed and compared to the simulation results obtained with numerical arm models of different complexity levels. The influence of the arm shape and size, as well as tissue composition and complexity is investigated.

Piezoelectric micromotor using a metal-ceramic composite structure.

PubMed

Koc, B; Bouchilloux, P; Uchino, K

2000-01-01

This paper presents a new piezoelectric micromotor design, in which a uniformly electroded piezoelectric ring bonded to a metal ring is used as the stator. Four inward arms at the inner circumference of the metal ring transfer radial displacements into tangential displacements. The rotor ends in a truncated cone shape and touches the tips of the arms. A rotation takes place by exciting coupled modes of the stator element, such as a radial mode and a second bending mode of the arms. The behavior of the free stator was analyzed using the ATILA finite element software. Torque vs. speed relationship was measured from the transient speed change with a motor load. A starting torque of 17 microNm was obtained at 20 Vrms. The main features of this motor are low cost and easy assembly because of a simple structure and small number of components.

Trying to Move Your Unseen Static Arm Modulates Visually-Evoked Kinesthetic Illusion

PubMed Central

Metral, Morgane; Blettery, Baptiste; Bresciani, Jean-Pierre; Luyat, Marion; Guerraz, Michel

2013-01-01

Although kinesthesia is known to largely depend on afferent inflow, recent data suggest that central signals originating from volitional control (efferent outflow) could also be involved and interact with the former to build up a coherent percept. Evidence derives from both clinical and experimental observations where vision, which is of primary importance in kinesthesia, was systematically precluded. The purpose of the present experiment was to assess the role of volitional effort in kinesthesia when visual information is available. Participants (n=20) produced isometric contraction (10-20% of maximal voluntary force) of their right arm while their left arm, which image was reflected in a mirror, either was passively moved into flexion/extension by a motorized manipulandum, or remained static. The contraction of the right arm was either congruent with or opposite to the passive displacements of the left arm. Results revealed that in most trials, kinesthetic illusions were visually driven, and their occurrence and intensity were modulated by whether volitional effort was congruent or not with visual signals. These results confirm the impact of volitional effort in kinesthesia and demonstrate for the first time that these signals interact with visual afferents to offer a coherent and unified percept. PMID:24348909

Next-generation sequencing analysis of the ARMS2 gene in Turkish exudative age-related macular degeneration patients.

PubMed

Bardak, H; Gunay, M; Ercalik, Y; Bardak, Y; Ozbas, H; Bagci, O

2017-01-23

Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries. It is a complex disease with both genetic and environmental risk factors. To improve clinical management of this condition, it is important to develop risk assessment and prevention strategies for environmental influences, and establish a more effective treatment approach. The aim of the present study was to investigate age-related maculopathy susceptibility protein 2 (ARMS2) gene sequences among Turkish patients with exudative AMD. In addition to 39 advanced exudative AMD patients, 250 healthy individuals for whom exome sequencing data were available were included as a control group. Patients with a history of known environmental and systemic AMD risk factors were excluded. Genomic DNA was isolated from peripheral blood and analyzed using next-generation sequencing. All coding exons of the ARMS2 gene were assessed. Three different ARMS2 sequence variations (rs10490923, rs2736911, and rs10490924) were identified in both the patient and control group. Within the control group, two further ARMS2 gene variants (rs7088128 and rs36213074) were also detected. Logistic regression analysis revealed a relationship between the rs10490924 polymorphism and AMD in the Turkish population.

Elucidating the role of transcription in shaping the 3D structure of the bacterial genome

NASA Astrophysics Data System (ADS)

Brandao, Hugo B.; Wang, Xindan; Rudner, David Z.; Mirny, Leonid

Active transcription has been linked to several genome conformation changes in bacteria, including the recruitment of chromosomal DNA to the cell membrane and formation of nucleoid clusters. Using genomic and imaging data as input into mathematical models and polymer simulations, we sought to explore the extent to which bacterial 3D genome structure could be explained by 1D transcription tracks. Using B. subtilis as a model organism, we investigated via polymer simulations the role of loop extrusion and DNA super-coiling on the formation of interaction domains and other fine-scale features that are visible in chromosome conformation capture (Hi-C) data. We then explored the role of the condensin structural maintenance of chromosome complex on the alignment of chromosomal arms. A parameter-free transcription traffic model demonstrated that mean chromosomal arm alignment can be quantitatively explained, and the effects on arm alignment in genomically rearranged strains of B. subtilis were accurately predicted. H.B. acknowledges support from the Natural Sciences and Engineering Research Council of Canada for a PGS-D fellowship.

Operator dynamics for stability condition in haptic and teleoperation system: A survey.

PubMed

Li, Hongbing; Zhang, Lei; Kawashima, Kenji

2018-04-01

Currently, haptic systems ignore the varying impedance of the human hand with its countless configurations and thus cannot recreate the complex haptic interactions. The literature does not reveal a comprehensive survey on the methods proposed and this study is an attempt to bridge this gap. The paper includes an extensive review of human arm impedance modeling and control deployed to address inherent stability and transparency issues in haptic interaction and teleoperation systems. Detailed classification and comparative study of various contributions in human arm modeling are presented and summarized in tables and diagrams. The main challenges in modeling human arm impedance for haptic robotic applications are identified. The possible future research directions are outlined based on the gaps identified in the survey. Copyright © 2018 John Wiley & Sons, Ltd.

Karyotypic analysis of the cotton boll weevil, Anthonomus grandis Boheman.

PubMed

McNally, L R; Beck, M L; Biggers, C J

2000-01-01

The diploid chromosome number of the cotton boll weevil, Anthonomus grandis Boheman, is 44. Both C- and N-banding techniques of mitotic cells demonstrated constitutive heterochromatin in the p arm of the eight largest chromosomes, the p arm of the X chromosome, and the centromeric region of autosomal groups A-D. Neither the y nor the group E autosomes appeared to contain constitutive heterochromatin. Supernumerary chromosomes were not found in the boll weevil. Restriction endonuclease banding of primary spermatocytes revealed a rod-shaped Xy tetrad in which the X and y were terminally associated. The p arm of the large, submetacentric X was C-band positive. While two of the autosomal tetrads were typically ring-shaped in primary spermatocytes, the remaining 19 autosomal tetrads were rod-shaped.

Genome-based insights into the resistome and mobilome of multidrug-resistant Aeromonas sp. ARM81 isolated from wastewater.

PubMed

Adamczuk, Marcin; Dziewit, Lukasz

2017-01-01

The draft genome of multidrug-resistant Aeromonas sp. ARM81 isolated from a wastewater treatment plant in Warsaw (Poland) was obtained. Sequence analysis revealed multiple genes conferring resistance to aminoglycosides, β-lactams or tetracycline. Three different β-lactamase genes were identified, including an extended-spectrum β-lactamase gene bla PER-1 . The antibiotic susceptibility was experimentally tested. Genome sequencing also allowed us to investigate the plasmidome and transposable mobilome of ARM81. Four plasmids, of which two carry phenotypic modules (i.e., genes encoding a zinc transporter ZitB and a putative glucosyltransferase), and 28 putative transposase genes were identified. The mobility of three insertion sequences (isoforms of previously identified elements ISAs12, ISKpn9 and ISAs26) was confirmed using trap plasmids.

Man-in-the-barrel. A case of cervical spinal cord infarction and review of the literature.

PubMed

Antelo, María José García; Facal, Teresa Lema; Sánchez, Tamara Pablos; Facal, María Soledad López; Nazabal, Eduardo Rubio

2013-01-01

Man-in-the-barrel syndrome was initially observed in patients with signs of serious cerebral hypoperfusion, in the border zone of the anterior and medial cerebral artery, but other causes were communicated later. a healthy 43-year-old woman who showed intense cervical pain, irradiating over both shoulders and arms. Physical examination on admission highlighted notable brachial diparesis, tacto-algesic hypoesthesia of both arms and sensory level C4-D9. cervical Magnetic Resonance Imaging (MRI) on admission revealed a hyperintense intramedullar lesion at C3-C7 level, due to a cervical cord infarction. our case reveals that conventional neurological consideration about the specific anatomical location of man-in-the-barrel syndrome in the brain should be extended to other locations such as the cervical column and not only the brain area.

REVIEW: Widespread access to predictive models in the motor system: a short review

NASA Astrophysics Data System (ADS)

Davidson, Paul R.; Wolpert, Daniel M.

2005-09-01

Recent behavioural and computational studies suggest that access to internal predictive models of arm and object dynamics is widespread in the sensorimotor system. Several systems, including those responsible for oculomotor and skeletomotor control, perceptual processing, postural control and mental imagery, are able to access predictions of the motion of the arm. A capacity to make and use predictions of object dynamics is similarly widespread. Here, we review recent studies looking at the predictive capacity of the central nervous system which reveal pervasive access to forward models of the environment.

Operation Sun Beam, Shot Small Boy. Project Officer's report - Project 7. 8. Arming and fuzing component test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taslitt, N.

1985-09-01

The objectives of this project were to (1) determine whether the radiation from a nuclear weapon can disable various arming and fuzing components by causing permanent damage; (2) determine whether transient nuclear radiation can induce an operating fuze to malfunction; and (3) compare nuclear weapon radiation effects with those produced by various radiation simulators. Data obtained revealed that none of the inertial components were detrimentally affected. The electronic components were severely degraded but would have satisfactorily accomplished their tactical functions. No electromagnetic effects were detected.

[The demand for blood transfusion agents and blood substitutes in the treatment of wounded patients].

PubMed

Zhiburt, E B; Danil'chenko, V V; Popova, N N; Vil'ianinov, V N

1999-09-01

Modern arms in combat tend to increase sanitary losses, change their structure and make combat traumas more severe. Blood transfusion therapy became a necessity in the wounds treatment. The recent armed conflicts made military medics move the blood transfusion service to the front lines. The authors present some data obtained in Afghanistan and Chechnya.

Attitude Control of Flexible Structures.

DTIC Science & Technology

1990-09-01

arm has been determined experimentally and compared with analytical * predictions obtained by using the GIFTS finite element analysis program. The...frequencies of the flexible arm have been determined experimentally and compared with analytical predictiens obtained by using the GIFTS finite element...exception of the first mode. Table V shows the difference between the frequencies obtained from the GIFTS program and the experimental values. TABLE

A History of Collisions Between the Magellanic Clouds

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-07-01

Recent deep observations of the Large Magellanic Cloud (LMC), a satellite galaxy of the Milky Way, have revealed a faint arc of stars extending from its northern outskirts. Was this stream created by the gravitational pull of the Milky Way? Or could it have a more violent source?The area surrounding the LMC. The stellar arc discovered with the Dark Energy Survey is shown in the region labeled A. The current study discovered additional asymmetric substructure in the region labeled C. [Besla et al. 2016]Searching for Spiral StructureWhen deep optical imaging by the Dark Energy Survey discovered this faint stream of stars extending eastward from the northern periphery of the LMC, scientists assumption was that this arm was created by the tidal pull of the Milky Way.But a team of authors led by Gurtina Besla (University of Arizona) argue for an alternate theory: what if this stellar stream was instead caused by repeated interactions between the LMC and the Small Magellanic Cloud (SMC)?One way to test these models is to look for a symmetrically corresponding arm in the south of the LMC extending west; such an arm would be expected if tidal forces from the Milky Way were acting globally on the LMC to create the northeast arm.The Dark Energy Surveys footprint doesnt cover the southern regions of the LMCs disk, but Besla and collaborators have an alternative: they performed their own wide-field survey using small robotic telescopes, which provide long exposures at low cost.Modeling Past and FutureInteractionsThe simulated interaction history of the LMC and SMC in isolation (i.e., without the Milky Way). The top left panel shows the SMCLMC separation as a function of time; the remaining panels show the system at different stages of the simulation. Only particles associated with the LMC are shown here; the SMCs position is indicated by a blue star. [Besla et al. 2016]The teams deep optical observations of the LMC and SMC fields confirmed the presence of asymmetric stellar arc structures in the northern outskirts of the LMC and they didnt find any corresponding structures in the southern region. This strongly supports the idea that the structures were caused by interactions between the LMC and the SMC, rather than by galactic tides.To further test this model, Besla and collaborators ran a series of simulations of interactions between LMC and SMC, first in isolation and then with the added tidal forces from the Milky Way.The simulations supported the conclusions drawn from the observations: while Milky Way tides may influence the final distribution of structures in the LMCs outskirts, close interactions between the LMC and the SMC appear to be the primary cause responsible for the asymmetric spiral structure found.As is shown in the authors simulations, the complete model of LMC/SMC interactions predicts that the two dwarfs will continue to interact until they eventually merge. Comparison of detailed simulations with future high-resolution observations of the LMC should help us further understand the interaction history of the LMC and SMC, thereby allowing us to better predict their eventual fate.BonusCheck out the gif below, cut from a video of the authors simulations. In these simulations, the SMC interacts with the LMC over the span of ~9 Gyr, passing through it several times before the LMC completely cannibalizes the SMC. You can visit the authors article to view the original video.CitationGurtina Besla et al 2016 ApJ 825 20. doi:10.3847/0004-637X/825/1/20

A new model for gravitational potential perturbations in disks of spiral galaxies. An application to our Galaxy

NASA Astrophysics Data System (ADS)

Junqueira, T. C.; Lépine, J. R. D.; Braga, C. A. S.; Barros, D. A.

2013-02-01

Aims: We propose a new, more realistic description of the perturbed gravitational potential of spiral galaxies, with spiral arms having Gaussian-shaped groove profiles. The aim is to reach a self-consistent description of the spiral structure, that is, one in which an initial potential perturbation generates, by means of the stellar orbits, spiral arms with a profile similar to that of the imposed perturbation. Self-consistency is a condition for having long-lived structures. Methods: Using the new perturbed potential, we investigate the stable stellar orbits in galactic disks for galaxies with no bar or with only a weak bar. The model is applied to our Galaxy by making use of the axisymmetric component of the potential computed from the Galactic rotation curve, in addition to other input parameters similar to those of our Galaxy. The influence of the bulge mass on the stellar orbits in the inner regions of a disk is also investigated. Results: The new description offers the advantage of easy control of the parameters of the Gaussian profile of its potential. We compute the density contrast between arm and inter-arm regions. We find a range of values for the perturbation amplitude from 400 to 800 km2 s-2 kpc-1, which implies an approximate maximum ratio of the tangential force to the axisymmetric force between 3% and 6%. Good self-consistency of arm shapes is obtained between the Inner Lindblad resonance (ILR) and the 4:1 resonance. Near the 4:1 resonance the response density starts to deviate from the imposed logarithmic spiral form. This creates bifurcations that appear as short arms. Therefore the deviation from a perfect logarithmic spiral in galaxies can be understood as a natural effect of the 4:1 resonance. Beyond the 4:1 resonance we find closed orbits that have similarities with the arms observed in our Galaxy. In regions near the center, elongated stellar orbits appear naturally, in the presence of a massive bulge, without imposing any bar-shaped potential, but only extending the spiral perturbation a little inward of the ILR. This suggests that a bar is formed with a half-size ~3 kpc by a mechanism similar to that of the spiral arms. Conclusions: The potential energy perturbation that we adopted represents an important step in the direction of self-consistency, compared to previous sine function descriptions of the potential. In addition, our model produces a realistic description of the spiral structure, which is able to explain several details that were not yet understood.

Feeding currents of the upside down jellyfish in the presence of background flow.

PubMed

Hamlet, Christina L; Miller, Laura A

2012-11-01

The upside-down jellyfish (Cassiopea spp.) is an ideal organism for examining feeding and exchange currents generated by bell pulsations due to its relatively sessile nature. Previous experiments and numerical simulations have shown that the oral arms play an important role in directing new fluid into the bell from along the substrate. All of this work, however, has considered the jellyfish in the absence of background flow, but the natural environments of Cassiopea and other cnidarians are dynamic. Flow velocities and directions fluctuate on multiple time scales, and mechanisms of particle capture may be fundamentally different in moving fluids. In this paper, the immersed boundary method is used to simulate a simplified jellyfish in flow. The elaborate oral arm structure is modeled as a homogenous porous layer. The results show that the oral arms trap vortices as they form during contraction and expansion of the bell. For constant flow conditions, the vortices are directed gently across the oral arms where particle capture occurs. For variable direction flows, the secondary structures change the overall pattern of the flow around the bell and appear to stabilize regions of mixing around the secondary mouths.

Gaseous spiral structure and mass drift in spiral galaxies

NASA Astrophysics Data System (ADS)

Kim, Yonghwi; Kim, Woong-Tae

2014-05-01

We use hydrodynamic simulations to investigate non-linear gas responses to an imposed stellar spiral potential in disc galaxies. The gaseous medium is assumed to be infinitesimally thin, isothermal, and unmagnetized. We consider various spiral-arm models with differing strength and pattern speed. We find that the extent and shapes of gaseous arms as well as the related mass drift rate depend rather sensitively on the arm pattern speed. In models where the arm pattern is rotating slow, the gaseous arms extend across the corotation resonance (CR) all the way to the outer boundary, with a pitch angle slightly smaller than that of the stellar counterpart. In models with a fast rotating pattern, on the other hand, spiral shocks are much more tightly wound than the stellar arms, and cease to exist in the regions near and outside the CR where mathcal {M}_perp /sin p_* gtrsim 25-40, with mathcal {M}_perp denoting the perpendicular Mach number of a rotating gas relative to the arms with pitch angle p*. Inside the CR, the arms drive mass inflows at a rate of ˜0.05-3.0 M⊙ yr-1 to the central region, with larger values corresponding to stronger and slower arms. The contribution of the shock dissipation, external torque, and self-gravitational torque to the mass inflow is roughly 50, 40, and 10 per cent, respectively. We demonstrate that the distributions of line-of-sight velocities and spiral-arm densities can be a useful diagnostic tool to distinguish if the spiral pattern is rotating fast or slow.

Designing Pattern Recognition-Based Method for Fast Visual Inspection of the Bucket Wheel Excavator Lattice Structure

NASA Astrophysics Data System (ADS)

Risteiu, M.; Lorincz, A.; Dobra, R.; Dasic, P.; Andras, I.; Roventa, M.

2017-06-01

The proposed paper shows some experimental results of a research in metallic structures inspection by using a high definition camera controller by high processing capabilities. The dedicated ARM Cortex-M4 initializes the ARM Cortex-M0 system for image acquiring. Then, by programming options, we are action for patterns (abnormal situations like metal cracks, or discontinuities) types and tuning, for enabling overexposure highlighting and adjusting camera brightness/exposure, to adjust minimum brightness, and to adjust the pattern’s teach threshold. The proposed system has been tested in normal lighting conditions from the typical site.

A Visual Analytics Approach to Structured Data Analysis to Enhance Nonproliferation and Arms Control Verification Activities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gillen, David S.

Analysis activities for Nonproliferation and Arms Control verification require the use of many types of data. Tabular structured data, such as Excel spreadsheets and relational databases, have traditionally been used for data mining activities, where specific queries are issued against data to look for matching results. The application of visual analytics tools to structured data enables further exploration of datasets to promote discovery of previously unknown results. This paper discusses the application of a specific visual analytics tool to datasets related to the field of Arms Control and Nonproliferation to promote the use of visual analytics more broadly in thismore » domain. Visual analytics focuses on analytical reasoning facilitated by interactive visual interfaces (Wong and Thomas 2004). It promotes exploratory analysis of data, and complements data mining technologies where known patterns can be mined for. Also with a human in the loop, they can bring in domain knowledge and subject matter expertise. Visual analytics has not widely been applied to this domain. In this paper, we will focus on one type of data: structured data, and show the results of applying a specific visual analytics tool to answer questions in the Arms Control and Nonproliferation domain. We chose to use the T.Rex tool, a visual analytics tool developed at PNNL, which uses a variety of visual exploration patterns to discover relationships in structured datasets, including a facet view, graph view, matrix view, and timeline view. The facet view enables discovery of relationships between categorical information, such as countries and locations. The graph tool visualizes node-link relationship patterns, such as the flow of materials being shipped between parties. The matrix visualization shows highly correlated categories of information. The timeline view shows temporal patterns in data. In this paper, we will use T.Rex with two different datasets to demonstrate how interactive exploration of the data can aid an analyst with arms control and nonproliferation verification activities. Using a dataset from PIERS (PIERS 2014), we will show how container shipment imports and exports can aid an analyst in understanding the shipping patterns between two countries. We will also use T.Rex to examine a collection of research publications from the IAEA International Nuclear Information System (IAEA 2014) to discover collaborations of concern. We hope this paper will encourage the use of visual analytics structured data analytics in the field of nonproliferation and arms control verification. Our paper outlines some of the challenges that exist before broad adoption of these kinds of tools can occur and offers next steps to overcome these challenges.« less

Adaptive Control Strategies for Flexible Robotic Arm

NASA Technical Reports Server (NTRS)

Bialasiewicz, Jan T.

1996-01-01

The control problem of a flexible robotic arm has been investigated. The control strategies that have been developed have a wide application in approaching the general control problem of flexible space structures. The following control strategies have been developed and evaluated: neural self-tuning control algorithm, neural-network-based fuzzy logic control algorithm, and adaptive pole assignment algorithm. All of the above algorithms have been tested through computer simulation. In addition, the hardware implementation of a computer control system that controls the tip position of a flexible arm clamped on a rigid hub mounted directly on the vertical shaft of a dc motor, has been developed. An adaptive pole assignment algorithm has been applied to suppress vibrations of the described physical model of flexible robotic arm and has been successfully tested using this testbed.

KSC-06pd2706

NASA Image and Video Library

2006-12-09

KENNEDY SPACE CENTER, FLA. -- On the morning of the second launch attempt, Space Shuttle Discovery is revealed after rollback of the rotating service structure. Seen above the golden external tank is the vent hood (known as the "beanie cap") at the end of the gaseous oxygen vent arm, extending from the fixed service structure. Vapors are created as the liquid oxygen in the external tank boil off. The hood vents the gaseous oxygen vapors away from the space shuttle vehicle. Below it, also extending toward Discovery from the FSS, is the orbiter access arm with the White Room at the end. The crew gains access into the orbiter through the White Room. Atop the FSS is the 80-foot-tall lightning mast. To the right of the shuttle is the water tower, containing 300 gallons of water used for sound suppression at liftoff. The first launch attempt of STS-116 Dec. 7 was postponed due a low cloud ceiling over Kennedy Space Center. The next launch attempt was scheduled for Saturday, Dec. 9, at 8:47 p.m. This will be Discovery's 33rd mission and the first night launch since 2002. The 20th shuttle mission to the International Space Station, STS-116 carries another truss segment, P5. It will serve as a spacer, mated to the P4 truss that was attached in September. After installing the P5, the crew will reconfigure and redistribute the power generated by two pairs of U.S. solar arrays. Landing is expected Dec. 19 at KSC. Photo credit: NASA/Ken Thornsley

LIFTING THE VEIL OF DUST TO REVEAL THE SECRETS OF SPIRAL GALAXIES

NASA Technical Reports Server (NTRS)

2002-01-01

Astronomers have combined information from the NASA Hubble Space Telescope's visible- and infrared-light cameras to show the hearts of four spiral galaxies peppered with ancient populations of stars. The top row of pictures, taken by a ground-based telescope, represents complete views of each galaxy. The blue boxes outline the regions observed by the Hubble telescope. The bottom row represents composite pictures from Hubble's visible- and infrared-light cameras, the Wide Field and Planetary Camera 2 (WFPC2) and the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). Astronomers combined views from both cameras to obtain the true ages of the stars surrounding each galaxy's bulge. The Hubble telescope's sharper resolution allows astronomers to study the intricate structure of a galaxy's core. The galaxies are ordered by the size of their bulges. NGC 5838, an 'S0' galaxy, is dominated by a large bulge and has no visible spiral arms; NGC 7537, an 'Sbc' galaxy, has a small bulge and loosely wound spiral arms. Astronomers think that the structure of NGC 7537 is very similar to our Milky Way. The galaxy images are composites made from WFPC2 images taken with blue (4445 Angstroms) and red (8269 Angstroms) filters, and NICMOS images taken in the infrared (16,000 Angstroms). They were taken in June, July, and August of 1997. Credits for the ground-based images: Allan Sandage (The Observatories of the Carnegie Institution of Washington) and John Bedke (Computer Sciences Corporation and the Space Telescope Science Institute) Credits for WFPC2 and NICMOS composites: NASA, ESA, and Reynier Peletier (University of Nottingham, United Kingdom)

Creating Time: Social Collaboration in Music Improvisation.

PubMed

Walton, Ashley E; Washburn, Auriel; Langland-Hassan, Peter; Chemero, Anthony; Kloos, Heidi; Richardson, Michael J

2018-01-01

Musical collaboration emerges from the complex interaction of environmental and informational constraints, including those of the instruments and the performance context. Music improvisation in particular is more like everyday interaction in that dynamics emerge spontaneously without a rehearsed score or script. We examined how the structure of the musical context affords and shapes interactions between improvising musicians. Six pairs of professional piano players improvised with two different backing tracks while we recorded both the music produced and the movements of their heads, left arms, and right arms. The backing tracks varied in rhythmic and harmonic information, from a chord progression to a continuous drone. Differences in movement coordination and playing behavior were evaluated using the mathematical tools of complex dynamical systems, with the aim of uncovering the multiscale dynamics that characterize musical collaboration. Collectively, the findings indicated that each backing track afforded the emergence of different patterns of coordination with respect to how the musicians played together, how they moved together, as well as their experience collaborating with each other. Additionally, listeners' experiences of the music when rating audio recordings of the improvised performances were related to the way the musicians coordinated both their playing behavior and their bodily movements. Accordingly, the study revealed how complex dynamical systems methods (namely recurrence analysis) can capture the turn-taking dynamics that characterized both the social exchange of the music improvisation and the sounds of collaboration more generally. The study also demonstrated how musical improvisation provides a way of understanding how social interaction emerges from the structure of the behavioral task context. Copyright © 2017 Cognitive Science Society, Inc.

Meiotic Cohesin SMC1β Provides Prophase I Centromeric Cohesion and Is Required for Multiple Synapsis-Associated Functions

PubMed Central

Biswas, Uddipta; Wetzker, Cornelia; Lange, Julian; Christodoulou, Eleni G.; Seifert, Michael; Beyer, Andreas; Jessberger, Rolf

2013-01-01

Cohesin subunit SMC1β is specific and essential for meiosis. Previous studies showed functions of SMC1β in determining the axis-loop structure of synaptonemal complexes (SCs), in providing sister chromatid cohesion (SCC) in metaphase I and thereafter, in protecting telomere structure, and in synapsis. However, several central questions remained unanswered and concern roles of SMC1β in SCC and synapsis and processes related to these two processes. Here we show that SMC1β substantially supports prophase I SCC at centromeres but not along chromosome arms. Arm cohesion and some of centromeric cohesion in prophase I are provided by non-phosphorylated SMC1α. Besides supporting synapsis of autosomes, SMC1β is also required for synapsis and silencing of sex chromosomes. In absence of SMC1β, the silencing factor γH2AX remains associated with asynapsed autosomes and fails to localize to sex chromosomes. Microarray expression studies revealed up-regulated sex chromosome genes and many down-regulated autosomal genes. SMC1β is further required for non-homologous chromosome associations observed in absence of SPO11 and thus of programmed double-strand breaks. These breaks are properly generated in Smc1β−/− spermatocytes, but their repair is delayed on asynapsed chromosomes. SMC1α alone cannot support non-homologous associations. Together with previous knowledge, three main functions of SMC1β have emerged, which have multiple consequences for spermatocyte biology: generation of the loop-axis architecture of SCs, homologous and non-homologous synapsis, and SCC starting in early prophase I. PMID:24385917

Voxel-based lesion-symptom mapping of stroke lesions underlying somatosensory deficits

PubMed Central

Meyer, Sarah; Kessner, Simon S.; Cheng, Bastian; Bönstrup, Marlene; Schulz, Robert; Hummel, Friedhelm C.; De Bruyn, Nele; Peeters, Andre; Van Pesch, Vincent; Duprez, Thierry; Sunaert, Stefan; Schrooten, Maarten; Feys, Hilde; Gerloff, Christian; Thomalla, Götz; Thijs, Vincent; Verheyden, Geert

2015-01-01

The aim of this study was to investigate the relationship between stroke lesion location and the resulting somatosensory deficit. We studied exteroceptive and proprioceptive somatosensory symptoms and stroke lesions in 38 patients with first-ever acute stroke. The Erasmus modified Nottingham Sensory Assessment was used to clinically evaluate somatosensory functioning in the arm and hand within the first week after stroke onset. Additionally, more objective measures such as the perceptual threshold of touch and somatosensory evoked potentials were recorded. Non-parametric voxel-based lesion-symptom mapping was performed to investigate lesion contribution to different somatosensory deficits in the upper limb. Additionally, structural connectivity of brain areas that demonstrated the strongest association with somatosensory symptoms was determined, using probabilistic fiber tracking based on diffusion tensor imaging data from a healthy age-matched sample. Voxels with a significant association to somatosensory deficits were clustered in two core brain regions: the central parietal white matter, also referred to as the sensory component of the superior thalamic radiation, and the parietal operculum close to the insular cortex, representing the secondary somatosensory cortex. Our objective recordings confirmed findings from clinical assessments. Probabilistic tracking connected the first region to thalamus, internal capsule, brain stem, postcentral gyrus, cerebellum, and frontal pathways, while the second region demonstrated structural connections to thalamus, insular and primary somatosensory cortex. This study reveals that stroke lesions in the sensory fibers of the superior thalamocortical radiation and the parietal operculum are significantly associated with multiple exteroceptive and proprioceptive deficits in the arm and hand. PMID:26900565

Embryonal rhabdomyosarcoma with a der(16)t(1;16) translocation.

PubMed

Kapels, Kayla M; Nishio, Jun; Zhou, Ming; Qualman, Stephen J; Bridge, Julia A

2007-04-01

Embryonal rhabdomyosarcoma (ERMS) is the most common subtype of RMS that predominantly involves the genitourinary tract and the head and neck regions in children younger than 10 years of age. Cytogenetically, ERMS is most frequently hyperdiploid, with extra copies of chromosomes 2, 7, 8, 11, 12, 13, and 20. No consistent structural chromosomal alteration has been identified in ERMS. In contrast, a t(2;13)(q35;q14) or t(1;13)(q36;q14) corresponding to PAX3-FOXO1A (previously FKHR) and PAX7-FOXO1A gene fusions are considered tumor-specific anomalies for alveolar RMS (ARMS). Occasionally, a recurrent secondary structural rearrangement involving chromosomes 1 and 16 is seen in translocation-positive ARMS, a der(16)t(1;16) resulting in an imbalance of 1q and 16q material. Conventional cytogenetic analysis of an ERMS arising in the urinary bladder of a 22-month-old male child revealed this nonrandom secondary chromosomal aberration, der(16)(1;16)(q22;q24), in a hyperdiploid complement with extra copies of chromosomes 2, 7, 8, 10, 12, 13, 19, and 20. Subsequent analyses showed tumor cells to be negative for FOXO1A, PAX3, or PAX7 gene locus rearrangements (by fluorescence in situ hybridization) and also negative for PAX3-FOXO1A and PAX7-FOXO1A fusion transcripts (by reverse transcriptase-polymerase chain reaction). These results suggest that the unbalanced t(1;16) translocation may be seen in RMSs lacking a primary genetic rearrangement.

Effects of arm truncation on the appearance of the halo artifact in 68Ga-PSMA-11 (HBED-CC) PET/MRI.

PubMed

Afshar-Oromieh, Ali; Wolf, Maya; Haberkorn, Uwe; Kachelrieß, Marc; Gnirs, Regula; Kopka, Klaus; Schlemmer, Heinz-Peter; Freitag, Martin T

2017-09-01

PSMA ligand imaging with hybrid PET/MRI scanners could be an integral part of the clinical routine in the future. However, the first study about this novel method revealed a severe photopenic artifact ("halo artifact") around the urinary bladder causing significantly reduced tumor visibility. The aim of this evaluation was to analyze the role of arm truncation on the appearance of the halo artifact in 68 Ga-PSMA-11 PET/MRI hypothesizing that this influences the appearance. Twenty-seven consecutive patients were subjected to 68 Ga-PSMA-11 PET/CT (1 h p.i.) followed by PET/MRI (3 h p.i.). PET/MRI was first started with scans of the abdomen to pelvis with arms positioned up above the head. Immediately thereafter, additional scans from the pelvis to abdomen were conducted with arms positioned down beside the trunk. All investigations were first analyzed separately and then compared with respect to tumor detection and tumor uptake (SUV) as well as the presence and intensity of the halo artifact. The Wilcoxon signed rank test was used to determine statistical differences including Bonferroni correction. The halo was significantly reduced if the arms were elevated. Lesions inside the halo artifact (n = 16) demonstrated significantly increased SUVmean (p = 0.0007) and SUVmax (p = 0.0024) with arms positioned up. The halo appearance and intensity was not dependent on the total activity and activity concentration of the urinary bladder. Positioning the arms down was shown to be significantly associated with the appearance of the halo artifact in PET/MRI. Positioning the arms up above the head can significantly reduce the halo artifact, thereby detecting more tumor lesions.

Structure and activity of the Cas3 HD nuclease MJ0384, an effector enzyme of the CRISPR interference

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beloglazova, Natalia; Petit, Pierre; Flick, Robert

Clustered regularly interspaced short palindromic repeats (CRISPRs) and Cas proteins represent an adaptive microbial immunity system against viruses and plasmids. Cas3 proteins have been proposed to play a key role in the CRISPR mechanism through the direct cleavage of invasive DNA. Here, we show that the Cas3 HD domain protein MJ0384 from Methanocaldococcus jannaschii cleaves endonucleolytically and exonucleolytically (3'-5') single-stranded DNAs and RNAs, as well as 3'-flaps, splayed arms, and R-loops. The degradation of branched DNA substrates by MJ0384 is stimulated by the Cas3 helicase MJ0383 and ATP. The crystal structure of MJ0384 revealed the active site with two boundmore » metal cations and together with site-directed mutagenesis suggested a catalytic mechanism. Our studies suggest that the Cas3 HD nucleases working together with the Cas3 helicases can completely degrade invasive DNAs through the combination of endo- and exonuclease activities.« less

Factor structure and longitudinal measurement invariance of PHQ-9 for specialist mental health care patients with persistent major depressive disorder: Exploratory Structural Equation Modelling.

PubMed

Guo, Boliang; Kaylor-Hughes, Catherine; Garland, Anne; Nixon, Neil; Sweeney, Tim; Simpson, Sandra; Dalgleish, Tim; Ramana, Rajini; Yang, Min; Morriss, Richard

2017-09-01

The Patient Health Questionnaire-9 (PHQ-9) is a widely used instrument for measuring levels of depression in patients in clinical practice and academic research; its factor structure has been investigated in various samples, with limited evidence of measurement equivalence/invariance (ME/I) but not in patients with more severe depression of long duration. This study aims to explore the factor structure of the PHQ-9 and the ME/I between treatment groups over time for these patients. 187 secondary care patients with persistent major depressive disorder (PMDD) were recruited to a randomised controlled trial (RCT) with allocation to either a specialist depression team arm or a general mental health arm; their PHQ-9 score was measured at baseline, 3, 6, 9 and 12 months. Exploratory Structural Equational Modelling (ESEM) was performed to examine the factor structure for this specific patient group. ME/I between treatment arm at and across follow-up time were further explored by means of multiple-group ESEM approach using the best-fitted factor structure. A two-factor structure was evidenced (somatic and affective factor). This two-factor structure had strong factorial invariance between the treatment groups at and across follow up times. Participants were largely white British in a RCT with 40% attrition potentially limiting the study's generalisability. Not all two-factor modelling criteria were met at every time-point. PHQ-9 has a two-factor structure for PMDD patients, with strong measurement invariance between treatment groups at and across follow-up time, demonstrating its validity for RCTs and prospective longitudinal studies in chronic moderate to severe depression. Copyright © 2017. Published by Elsevier B.V.

Helix-coil transition of a four-way DNA junction observed by multiple fluorescence parameters.

PubMed

Vámosi, György; Clegg, Robert M

2008-10-16

The thermal denaturation of immobile four-way DNA ("Holliday-") junctions with 17 base pair arms was studied via fluorescence spectroscopic measurements. Two arms of the molecule were labeled at the 5'-end with fluorescein and tetramethylrhodamine, respectively. Melting was monitored by the fluorescence intensity of the dyes, the fluorescence anisotropy of tetramethylrhodamine, and Forster resonance energy transfer (FRET) between fluorescein and rhodamine. To fit the thermal denaturation curves of the four-way junctions, two basic thermodynamic models were tested: (1) all-or-none transitions assuming a molecularity of one, two, or four and (2) a statistical "zipper" model. The all-or-none models correspond to reaction mechanisms assuming that the cooperative melting unit (that is, the structure changing from complete helix to complete coil) consists of (1) one arm, (2) two neighboring arms (which have one continuous strand common to the two arms), or (3) all four arms. In each case, the melting of the cooperative unit takes place in a single step. The tetramolecular reaction model (four-arm melting) yielded unrealistically low van't Hoff enthalpy and entropy values, whereas the monomolecular model (one-arm melting) resulted in a poor fit to the experimental data. The all-or-none bimolecular (two neighboring arm model) fit gave intermediate standard enthalpy change (Delta H) values between those expected for the melting of a duplex with a total length between the helix lengths of one and two arms (17 and 34 base pairs). Simulations according to the zipper model fit the experimental curves best when the length of the simulated duplex was assumed to be 34 base pairs, the length of a single strand. This suggests that the most important parameter determining the melting behavior of the molecule is the end-to-end distance of the strands (34 bases) rather than the length of the individual arms (17 base pairs) and that the equilibrium concentration of partially denatured intermediate states has to be taken into account. These findings are in good agreement with results obtained for three-way DNA junctions ( Stuhmeier, F. ; Lilley, D. M. ; Clegg, R. M. Biochemistry 1997, 36, 13539 ). An interesting result is that the extent-of-melting curves derived from the fluorescence intensity and anisotropy nearly agree, whereas the curve derived from the FRET data shows a change prior to the melting. This may be an indication of a conformational change leaving the double-stranded structure intact but changing the end-to-end distance of the different arms in a way consistent with the transition to the extended square configuration ( Clegg, R. M. ; Murchie, A. I. ; Lilley, D. M. Biophys. J. 1994, 66, 99 ) of this branched molecule.

Clinical and Genetic Aspects of Primary Ciliary Dyskinesia / Kartagener Syndrome

PubMed Central

Leigh, Margaret W.; Pittman, Jessica E.; Carson, Johnny L.; Ferkol, Thomas W.; Dell, Sharon D.; Davis, Stephanie D.; Knowles, Michael R.; Zariwala, Maimoona A.

2013-01-01

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder of motile cilia. Most of the disease-causing mutations identified to date involve the heavy (DNAH5) or intermediate (DNAI1) chain dynein genes in ciliary outer dynein arms, although a few mutations have been noted in other genes. Clinical molecular genetic testing for PCD is available for the most common mutations. The respiratory manifestations of PCD (chronic bronchitis leading to bronchiectasis, chronic rhino-sinusitis and chronic otitis media) reflect impaired mucociliary clearance owing to defective axonemal structure. Ciliary ultrastructural analysis in most patients (>80%) reveals defective dynein arms, although defects in other axonemal components have also been observed. Approximately 50% of PCD patients have laterality defects (including situs inversus totalis and, less commonly, heterotaxy and congenital heart disease), reflecting dysfunction of embryological nodal cilia. Male infertility is common and reflects defects in sperm tail axonemes. Most PCD patients have a history of neonatal respiratory distress, suggesting that motile cilia play a role in fluid clearance during the transition from a fetal to neonatal lung. Ciliopathies involving sensory cilia, including autosomal dominant or recessive polycystic kidney disease, Bardet-Biedl syndrome, and Alstrom syndrome, may have chronic respiratory symptoms and even bronchiectasis suggesting clinical overlap with PCD. PMID:19606528

KSC01PD1742

NASA Image and Video Library

2001-11-28

KENNEDY SPACE CENTER, Fla. -- Space Shuttle Endeavour is revealed after rollback of the Rotating Service Structure on Launch Pad 39B. Seen is one of the twin solid rocket boosters that flank the orange external tank. Above the external tank is the Gaseous Oxygen Vent Arm that vents gaseous oxygen vapors away from the Shuttle. The vent hood assembly at the end is often referred to as the "beanie cap." Stretching to the crew hatch on the side is the Orbiter Access Arm with its environmentally controlled White Room at the end. The Shuttle sits on the Mobile Launcher Platform with the two service tail masts on either side of the main engines. The tail masts support the fluid, gas and electrical requirements of the orbiter's liquid oxygen and liquid hydrogen aft T-0 umbilicals. Each tail mast is 31 feet (9.4 meters) high, 15 feet (4.6 meters) long and 9 feet (3.1 meters) wide. Endeavour is scheduled to launch on mission STS-108 Nov. 29 at 7:41 p.m. On this 12th flight to the International Space Station, known as a Utilization Flight, Endeavour will carry a crew of four plus the Expedition 4 crew, who will replace Expedition 3 aboard the ISS. The payload includes the Multi-Purpose Logistics Module Raffaello, filled with supplies, equipment and experiments

Localization and quantification of carbonic anhydrase activity in the symbiotic Scyphozoan Cassiopea xamachana.

PubMed

Estes, Anne M; Kempf, Stephen C; Henry, Raymond P

2003-06-01

The relationship between density and location of zooxanthellae and levels of carbonic anhydrase (CA) activity was examined in Cassiopea xamachana. In freshly collected symbiotic animals, high densities of zooxanthellae corresponded with high levels of CA activity in host bell and oral arm tissues. Bleaching resulted in a significant loss of zooxanthellae and CA activity. Recolonization resulted in full restoration of zooxanthellar densities but only partial restoration of CA activity. High levels of CA activity were also seen in structures with inherently higher zooxanthellar densities, such as oral arm tissues. Similarly, the oral epidermal layer of bell tissue had significantly higher zooxanthellar densities and levels of CA activity than did aboral bell tissues. Fluorescent labeling, using 5-dimethylaminonapthalene-1-sulfonamide (DNSA) also reflected this tight-knit relationship between the presence and density of zooxanthellae, as DNSA-CA fluorescence intensity was greatest in host oral epithelial cells directly overlying zooxanthellae. However, the presence and density of zooxanthellae did not always correspond with enzyme activity levels. A transect of bell tissue from the margin to the manubrium revealed a gradient of CA activity, with the highest values at the bell margin and the lowest at the manubrium, despite an even distribution of zooxanthellae. Thus, abiotic factors may also influence the distribution of CA and the levels of CA activity.

Use of a novel FISH assay on paraffin-embedded tissues as an adjunct to diagnosis of alveolar rhabdomyosarcoma.

PubMed

Nishio, Jun; Althof, Pamela A; Bailey, Jacqueline M; Zhou, Ming; Neff, James R; Barr, Frederic G; Parham, David M; Teot, Lisa; Qualman, Stephen J; Bridge, Julia A

2006-06-01

A valuable diagnostic adjunct and important prognostic parameter in alveolar rhabdomyosarcoma (ARMS) is the identification of translocations t(2;13)(q35;q14) and t(1;13)(p36;q14), and the associated PAX3-FKHR and PAX7-FKHR fusion transcripts, respectively. Most RMS fusion gene type studies have been based on reverse transcriptase-polymerase chain reaction (RT-PCR) detection of the fusion transcript, a technique limited by RNA quality and failure of devised primer sets to detect unusual variants. As an alternative approach, we developed a fluorescence in situ hybridization (FISH) assay that can: (1) distinguish between the two most common ARMS-associated fusion genes; (2) identify potential unusual variant translocations; (3) assess histologic components in mixed alveolar/embryonal RMS; and (4) be performed on paraffinized tissue. FISH analyses of 75 specimens (40 ARMS, 16 ERMS, 8 mixed ARMS/ERMS, and 11 non-RMS tumors) using selected cosmid clone, bacterial, P1-derived, and yeast artificial chromosome probe sets were successful in all but two cases. Among specimens with informative results for both FISH and RT-PCR or standard karyotyping, PAX/FKHR classification results were concordant in 94.6% (53/56). The three discordant cases included one exhibiting a t(2;13) by FISH that was subsequently confirmed by repeat RT-PCR, a second showing a rearrangement of the PAX3 locus only (consistent with the presence of a PAX3 variant translocation), and a third revealing a t(2;13) by FISH that lacked this translocation cytogenetically. Both alveolar and embryonal components of the mixed ARMS/ERMS subtype were negative for PAX3, PAX7, and FKHR rearrangements, a surprising finding confirmed by RT-PCR and/or conventional karyotyping. These data demonstrate that FISH with newly designed probe sets is a reliable and highly specific method of detecting t(1;13) and t(2;13) in routinely processed tissue and may be useful in differentiating ARMS from other small round cell tumors. The findings also suggest that FISH may be a more sensitive assay than RT-PCR in some settings, capable of revealing variant translocations.

Structural principles within the human-virus protein-protein interaction network

PubMed Central

Franzosa, Eric A.; Xia, Yu

2011-01-01

General properties of the antagonistic biomolecular interactions between viruses and their hosts (exogenous interactions) remain poorly understood, and may differ significantly from known principles governing the cooperative interactions within the host (endogenous interactions). Systems biology approaches have been applied to study the combined interaction networks of virus and human proteins, but such efforts have so far revealed only low-resolution patterns of host-virus interaction. Here, we layer curated and predicted 3D structural models of human-virus and human-human protein complexes on top of traditional interaction networks to reconstruct the human-virus structural interaction network. This approach reveals atomic resolution, mechanistic patterns of host-virus interaction, and facilitates systematic comparison with the host’s endogenous interactions. We find that exogenous interfaces tend to overlap with and mimic endogenous interfaces, thereby competing with endogenous binding partners. The endogenous interfaces mimicked by viral proteins tend to participate in multiple endogenous interactions which are transient and regulatory in nature. While interface overlap in the endogenous network results largely from gene duplication followed by divergent evolution, viral proteins frequently achieve interface mimicry without any sequence or structural similarity to an endogenous binding partner. Finally, while endogenous interfaces tend to evolve more slowly than the rest of the protein surface, exogenous interfaces—including many sites of endogenous-exogenous overlap—tend to evolve faster, consistent with an evolutionary “arms race” between host and pathogen. These significant biophysical, functional, and evolutionary differences between host-pathogen and within-host protein-protein interactions highlight the distinct consequences of antagonism versus cooperation in biological networks. PMID:21680884

Kinematics analysis on hinges of robot arm gripper for harmful chemical handling

NASA Astrophysics Data System (ADS)

Razali, Zol Bahri; Kader, Mohamed Mydin M. Abdul; Mustafa, Nurul Fahimah; Daud, Mohd Hisam

2017-09-01

The development of manufacturing industry is booming the application of industrial robot, and proportional to the use of robot arm. Some of the purpose of robot arm gripper is to sort things and place to the proper place. And some of the things are harmful to human, such as harmful chemical. By using robot arm to do picking and placing, it is expected to replace human tasks, as well as to reduce human from the harmful job. The problem of the robot arm gripper, most likely the problem of hinge, thus the analysis on the hinges of robot arm gripper to prevent claw is essential. By using robot arm, instead of human, is labored to do the harmful tasks and unexpected accident happen, costs and expenses in handling injured employee due to the harmful chemicals can be minimized. Thus the objective of this project is to make a kinematics analysis on the hinges of the robot arm gripper. Suitable material such as steel structure has also been selected for the construction of this hinges. This material has properties associated with compressive strength, fire resistance, corrosion and has a shape that is easy to move. Solid Works and ANSYS software is used to create animated movement on the design model and to detect deficiencies in the hinges. Detail methodology is described in this paper.

RM-10A robotic manipulator system

DOE Office of Scientific and Technical Information (OSTI.GOV)

White, J.R.; Coughlan, J.B.; Harvey, H.W.

1988-01-01

The REMOTE RM-10A is a man-replacement manipulator system that has been developed specifically for use in radioactive and other hazardous environments. It can be teleoperated, with man-in-the-loop, for unstructured tasks or programmed to perform routine tasks automatically much like robots in the automated manufacturing industry. The RM-10A is a servomanipulator utilizing a closed-loop, microprocessor-based control system. The system consists of a slave assembly, master control station, and interconnecting cabling. The slave assembly is the part of the system that enters the hostile environment. It is man-like is size and configuration with two identical arms attached to a torso structure. Eachmore » arm attaches to the torso using two captive screws and two guide pins. The guide pins position and stabilize an arm during removal and reinstallation and also align the two electrical connectors located in the arm support plate and torso. These features allow easy remote replacement of an arm, and commonality of the arms allow interchangeability. The water-resistant slave assembly is equipped with gaskets and O-ring seals in the torso and arm and camera assemblies. In addition, each slave arm's elbow, wrist, and tong are protected by replaceable polyurethane boots. An upper camera assembly, consisting of a color television (TV) camera, 6:1 zoom lens, and a pan/tilt unit, mount to the torso to provide remote viewing capability.« less

Kinematic imprints from the bar and spiral structures in the galatic disk

NASA Astrophysics Data System (ADS)

Figueras, F.; Antoja, T.; Valenzuela, O.; Romero-Gómez, M.; Pichardo, B.; Moreno, E.

2011-12-01

At 140 years of the discovery of the moving groups, these stellar streams are emerging as powerful tools to constrain the models for the spiral arms and the Galactic bar in the Gaia era. From the kinematic-age-metallicity analysis in the solar neighbourhood it is now well established that some of these kinematic structures have a dynamical origin, different from the classical cluster disruption hypothesis. Test particle simulations allow us to definitively establish that these local structures can be created by the dynamical resonances of material spiral arms and not exclusively by the Galactic bar. First studies to evaluate the capabilities of the future Gaia data to detect and characterize moving groups at 2-6 kpc from the solar neighborhood are discussed.

Definition of ground test for verification of large space structure control

NASA Technical Reports Server (NTRS)

Seltzer, S. M.; Doane, G. B., III

1985-01-01

Directions regarding the analytical models were received. A counter balance arm with weights was added at the top of the ASTROMAST to offset the arm with the gimbals. In addition to this model, three more models were requested from MSFC: structure as in the revised model with the addition of lumped masses at bays 46 and 91 of the ASTROMAST; cantilevered cruciform structure with lumped masses at bays 46 and 91, and an all up cruciform structure with lumped masses at bays 46 and 91. Figures for each model and their corresponding natural frequencies and general mode shapes associated with these frequencies are included. The drawbar in use in the cruciform models must be incorporated into the antenna and ASTROMAST models. The total tensile load carrying capability of the ASTROMAST is approximately 840 pounds.

Deciphering the Hidden Informational Content of Protein Sequences

PubMed Central

Liu, Ming; Hua, Qing-xin; Hu, Shi-Quan; Jia, Wenhua; Yang, Yanwu; Saith, Sunil Evan; Whittaker, Jonathan; Arvan, Peter; Weiss, Michael A.

2010-01-01

Protein sequences encode both structure and foldability. Whereas the interrelationship of sequence and structure has been extensively investigated, the origins of folding efficiency are enigmatic. We demonstrate that the folding of proinsulin requires a flexible N-terminal hydrophobic residue that is dispensable for the structure, activity, and stability of the mature hormone. This residue (PheB1 in placental mammals) is variably positioned within crystal structures and exhibits 1H NMR motional narrowing in solution. Despite such flexibility, its deletion impaired insulin chain combination and led in cell culture to formation of non-native disulfide isomers with impaired secretion of the variant proinsulin. Cellular folding and secretion were maintained by hydrophobic substitutions at B1 but markedly perturbed by polar or charged side chains. We propose that, during folding, a hydrophobic side chain at B1 anchors transient long-range interactions by a flexible N-terminal arm (residues B1–B8) to mediate kinetic or thermodynamic partitioning among disulfide intermediates. Evidence for the overall contribution of the arm to folding was obtained by alanine scanning mutagenesis. Together, our findings demonstrate that efficient folding of proinsulin requires N-terminal sequences that are dispensable in the native state. Such arm-dependent folding can be abrogated by mutations associated with β-cell dysfunction and neonatal diabetes mellitus. PMID:20663888

Detection of physical activities using a physical activity monitor system for wheelchair users.

PubMed

Hiremath, Shivayogi V; Intille, Stephen S; Kelleher, Annmarie; Cooper, Rory A; Ding, Dan

2015-01-01

Availability of physical activity monitors for wheelchair users can potentially assist these individuals to track regular physical activity (PA), which in turn could lead to a healthier and more active lifestyle. Therefore, the aim of this study was to develop and validate algorithms for a physical activity monitoring system (PAMS) to detect wheelchair based activities. The PAMS consists of a gyroscope based wheel rotation monitor (G-WRM) and an accelerometer device (wocket) worn on the upper arm or on the wrist. A total of 45 persons with spinal cord injury took part in the study, which was performed in a structured university-based laboratory environment, a semi-structured environment at the National Veterans Wheelchair Games, and in the participants' home environments. Participants performed at least ten PAs, other than resting, taken from a list of PAs. The classification performance for the best classifiers on the testing dataset for PAMS-Arm (G-WRM and wocket on upper arm) and PAMS-Wrist (G-WRM and wocket on wrist) was 89.26% and 88.47%, respectively. The outcomes of this study indicate that multi-modal information from the PAMS can help detect various types of wheelchair-based activities in structured laboratory, semi-structured organizational, and unstructured home environments. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.

The Effect of a Multi-Level Intervention on the Initiation of Antiretroviral Therapy (ART) among HIV-Infected Men Who Inject Drugs and Were Diagnosed Late in Thai Nguyen, Vietnam

PubMed Central

Zelaya, Carla E.; Le Minh, Nguyen; Lau, Bryan; Latkin, Carl A.; Viet Ha, Tran; Minh Quan, Vu; Mo, Thi Tran; Sripaipan, Teerada; Davis, Wendy W.; Celentano, David D.; Frangakis, Constantine; Go, Vivian F.

2016-01-01

Background In Vietnam, an estimated 256,000 people are living with HIV, and 58% of HIV-infections reported are among people who inject drugs (PWID). While antiretroviral therapy (ART) is widely available in Vietnam, marginalized hard-to-reach male PWID, demonstrate significantly reduced and delayed access to ART. Methods We investigated the effect of a randomized four-arm multi-level intervention trial on ART initiation among male PWID. Our analysis was conducted among a subset of trial participants (n = 136), who were newly diagnosed as HIV-infected, treatment naïve, and eligible for ART (baseline late diagnosis). The trial arms included: 1, standard of care (HIV testing and counseling); 2, structural-level intervention (door-to-door communications and community video screenings); 3, individual-level intervention (counseling plus group support); and 4, individual-level plus structural-level intervention. In a time-to-event analysis, we used a non-parametric approach for competing risks to estimate cumulative incidence function (CIF) for ART initiation (event of interest) by arm and the difference in CIF for each trial arm as compared to Arm 1. Follow-up was conducted at 6, 12, 18 and 24 months. Data collection occurred from 2009 to 2013. Findings By 24-months, 61.0% initiated ART, and 30.9% had died prior to ART initiation. In the first 6 months, participants in arm 4 (individual plus community intervention) had a 28% (95% confidence interval (CI): 6–50%) increased probability of initiating ART. Despite increasing coverage of ART in all arms throughout follow-up, participants in arm 4 retained a 31% (95% CI: 5–56%) increased probability of initiating ART. The individual and community components of the intervention were only effective when delivered together. Conclusions Marginalized, hard-to-reach men, who do not routinely engage in HIV services, and therefore come into care late, may benefit significantly from both individual counseling and group support, in combination with community-focused stigma reduction, when being referred and attempting to initiate urgently needed ART. PMID:27579772

The Effect of a Multi-Level Intervention on the Initiation of Antiretroviral Therapy (ART) among HIV-Infected Men Who Inject Drugs and Were Diagnosed Late in Thai Nguyen, Vietnam.

PubMed

Zelaya, Carla E; Le Minh, Nguyen; Lau, Bryan; Latkin, Carl A; Viet Ha, Tran; Minh Quan, Vu; Mo, Thi Tran; Sripaipan, Teerada; Davis, Wendy W; Celentano, David D; Frangakis, Constantine; Go, Vivian F

2016-01-01

In Vietnam, an estimated 256,000 people are living with HIV, and 58% of HIV-infections reported are among people who inject drugs (PWID). While antiretroviral therapy (ART) is widely available in Vietnam, marginalized hard-to-reach male PWID, demonstrate significantly reduced and delayed access to ART. We investigated the effect of a randomized four-arm multi-level intervention trial on ART initiation among male PWID. Our analysis was conducted among a subset of trial participants (n = 136), who were newly diagnosed as HIV-infected, treatment naïve, and eligible for ART (baseline late diagnosis). The trial arms included: 1, standard of care (HIV testing and counseling); 2, structural-level intervention (door-to-door communications and community video screenings); 3, individual-level intervention (counseling plus group support); and 4, individual-level plus structural-level intervention. In a time-to-event analysis, we used a non-parametric approach for competing risks to estimate cumulative incidence function (CIF) for ART initiation (event of interest) by arm and the difference in CIF for each trial arm as compared to Arm 1. Follow-up was conducted at 6, 12, 18 and 24 months. Data collection occurred from 2009 to 2013. By 24-months, 61.0% initiated ART, and 30.9% had died prior to ART initiation. In the first 6 months, participants in arm 4 (individual plus community intervention) had a 28% (95% confidence interval (CI): 6-50%) increased probability of initiating ART. Despite increasing coverage of ART in all arms throughout follow-up, participants in arm 4 retained a 31% (95% CI: 5-56%) increased probability of initiating ART. The individual and community components of the intervention were only effective when delivered together. Marginalized, hard-to-reach men, who do not routinely engage in HIV services, and therefore come into care late, may benefit significantly from both individual counseling and group support, in combination with community-focused stigma reduction, when being referred and attempting to initiate urgently needed ART.

Cannabis use and brain structural alterations of the cingulate cortex in early psychosis.

PubMed

Rapp, Charlotte; Walter, Anna; Studerus, Erich; Bugra, Hilal; Tamagni, Corinne; Röthlisberger, Michel; Borgwardt, Stefan; Aston, Jacqueline; Riecher-Rössler, Anita

2013-11-30

As cannabis use is more frequent in patients with psychosis than in the general population and is known to be a risk factor for psychosis, the question arises whether cannabis contributes to recently detected brain volume reductions in schizophrenic psychoses. This study is the first to investigate how cannabis use is related to the cingulum volume, a brain region involved in the pathogenesis of schizophrenia, in a sample of both at-risk mental state (ARMS) and first episode psychosis (FEP) subjects. A cross-sectional magnetic resonance imaging (MRI) study of manually traced cingulum in 23 FEP and 37 ARMS subjects was performed. Cannabis use was assessed with the Basel Interview for Psychosis. By using repeated measures analyses of covariance, we investigated whether current cannabis use is associated with the cingulum volume, correcting for age, gender, alcohol consumption, whole brain volume and antipsychotic medication. There was a significant three-way interaction between region (anterior/posterior cingulum), hemisphere (left/right cingulum) and cannabis use (yes/no). Post-hoc analyses revealed that this was due to a significant negative effect of cannabis use on the volume of the posterior cingulum which was independent of the hemisphere and diagnostic group and all other covariates we controlled for. In the anterior cingulum, we found a significant negative effect only for the left hemisphere, which was again independent of the diagnostic group. Overall, we found negative associations of current cannabis use with grey matter volume of the cingulate cortex, a region rich in cannabinoid CB1 receptors. As this finding has not been consistently found in healthy controls, it might suggest that both ARMS and FEP subjects are particularly sensitive to exogenous activation of these receptors. © 2013 Elsevier Ireland Ltd. All rights reserved.

High resolution immunoelectron microscopic localization of functional domains of laminin, nidogen, and heparan sulfate proteoglycan in epithelial basement membrane of mouse cornea reveals different topological orientations.

PubMed

Schittny, J C; Timpl, R; Engel, J

1988-10-01

Thin and ultrathin cryosections of mouse cornea were labeled with affinity-purified antibodies directed against either laminin, its central segments (domain 1), the end of its long arm (domain 3), the end of one of its short arms (domain 4), nidogen, or low density heparan sulfate proteoglycan. All basement membrane proteins are detected by indirect immunofluorescence exclusively in the epithelial basement membrane, in Descemet's membrane, and in small amorphous plaques located in the stroma. Immunoelectron microscopy using the protein A-gold technique demonstrated laminin domain 1 and nidogen in a narrow segment of the lamina densa at the junction to the lamina lucida within the epithelial basement membrane. Domain 3 shows three preferred locations at both the cellular and stromal boundaries of the epithelial basement membrane and in its center. Domain 4 is located predominantly in the lamina lucida and the adjacent half of the lamina densa. The low density heparan sulfate proteoglycan is found all across the basement membrane showing a similar uniform distribution as with antibodies against the whole laminin molecule. In Descemet's membrane an even distribution was found with all these antibodies. It is concluded that within the epithelial basement membrane the center of the laminin molecule is located near the lamina densa/lamina lucida junction and that its long arm favors three major orientations. One is close to the cell surface indicating binding to a cell receptor, while the other two are directed to internal matrix structures. The apparent codistribution of laminin domain 1 and nidogen agrees with biochemical evidence that nidogen binds to this domain.

Shamba Maisha: Pilot agricultural intervention for food security and HIV health outcomes in Kenya: design, methods, baseline results and process evaluation of a cluster-randomized controlled trial.

PubMed

Cohen, Craig R; Steinfeld, Rachel L; Weke, Elly; Bukusi, Elizabeth A; Hatcher, Abigail M; Shiboski, Stephen; Rheingans, Richard; Scow, Kate M; Butler, Lisa M; Otieno, Phelgona; Dworkin, Shari L; Weiser, Sheri D

2015-01-01

Despite advances in treatment of people living with HIV, morbidity and mortality remains unacceptably high in sub-Saharan Africa, largely due to parallel epidemics of poverty and food insecurity. We conducted a pilot cluster randomized controlled trial (RCT) of a multisectoral agricultural and microfinance intervention (entitled Shamba Maisha) designed to improve food security, household wealth, HIV clinical outcomes and women's empowerment. The intervention was carried out at two HIV clinics in Kenya, one randomized to the intervention arm and one to the control arm. HIV-infected patients >18 years, on antiretroviral therapy, with moderate/severe food insecurity and/or body mass index (BMI) <18.5, and access to land and surface water were eligible for enrollment. The intervention included: 1) a microfinance loan (~$150) to purchase the farming commodities, 2) a micro-irrigation pump, seeds, and fertilizer, and 3) trainings in sustainable agricultural practices and financial literacy. Enrollment of 140 participants took four months, and the screening-to-enrollment ratio was similar between arms. We followed participants for 12 months and conducted structured questionnaires. We also conducted a process evaluation with participants and stakeholders 3-5 months after study start and at study end. Baseline results revealed that participants at the two sites were similar in age, gender and marital status. A greater proportion of participants at the intervention site had a low BMI in comparison to participants at the control site (18% vs. 7%, p = 0.054). While median CD4 count was similar between arms, a greater proportion of participants enrolled at the intervention arm had a detectable HIV viral load compared with control participants (49% vs. 28%, respectively, p < 0.010). Process evaluation findings suggested that Shamba Maisha had high acceptability in recruitment, delivered strong agricultural and financial training, and led to labor saving due to use of the water pump. Implementation challenges included participant concerns about repaying loans, agricultural challenges due to weather patterns, and a challenging partnership with the microfinance institution. We expect the results from this pilot study to provide useful data on the impacts of livelihood interventions and will help in the design of a definitive cluster RCT. This trial is registered at ClinicalTrials.gov, NCT01548599.

Using shape to turn off blinking for two-colour multiexciton emission in CdSe/CdS tetrapods

NASA Astrophysics Data System (ADS)

Mishra, Nimai; Orfield, Noah J.; Wang, Feng; Hu, Zhongjian; Krishnamurthy, Sachidananda; Malko, Anton V.; Casson, Joanna L.; Htoon, Han; Sykora, Milan; Hollingsworth, Jennifer A.

2017-05-01

Semiconductor nanostructures capable of emitting from two excited states and thereby of producing two photoluminescence colours are of fundamental and potential technological significance. In this limited class of nanocrystals, CdSe/CdS core/arm tetrapods exhibit the unusual trait of two-colour (red and green) multiexcitonic emission, with green emission from the CdS arms emerging only at high excitation fluences. Here we show that by synthetic shape-tuning, both this multi-colour emission process, and blinking and photobleaching behaviours of single tetrapods can be controlled. Specifically, we find that the properties of dual emission and single-nanostructure photostability depend on different structural parameters--arm length and arm diameter, respectively--but that both properties can be realized in the same nanostructure. Furthermore, based on results of correlated photoluminescence and transient absorption measurements, we conclude that hole-trap filling in the arms and partial state-filling in the core are necessary preconditions for the observation of multiexciton multi-colour emission.

Beam rider for an Articulated Robot Manipulator (ARM) accurate positioning of long flexible manipulators

NASA Technical Reports Server (NTRS)

Malachowski, M. J.

1990-01-01

Laser beam positioning and beam rider modules were incorporated into the long hollow flexible segment of an articulated robot manipulator (ARM). Using a single laser beam, the system determined the position of the distal ARM endtip, with millimetric precision, in six degrees of freedom, at distances of up to 10 meters. Preliminary designs, using space rated technology for the critical systems, of a two segmented physical ARM, with a single and a dual degree of freedom articulation, were developed, prototyped, and tested. To control the positioning of the physical ARM, an indirect adaptive controller, which used the mismatch between the position of the laser beam under static and dynamic conditions, was devised. To predict the behavior of the system and test the concept, a computer simulation model was constructed. A hierarchical artificially intelligent real time ADA operating system program structure was created. The software was designed for implementation on a dedicated VME bus based Intel 80386 administered parallel processing multi-tasking computer system.

Using shape to turn off blinking for two-colour multiexciton emission in CdSe/CdS tetrapods

PubMed Central

Mishra, Nimai; Orfield, Noah J.; Wang, Feng; Hu, Zhongjian; Krishnamurthy, Sachidananda; Malko, Anton V.; Casson, Joanna L.; Htoon, Han; Sykora, Milan; Hollingsworth, Jennifer A.

2017-01-01

Semiconductor nanostructures capable of emitting from two excited states and thereby of producing two photoluminescence colours are of fundamental and potential technological significance. In this limited class of nanocrystals, CdSe/CdS core/arm tetrapods exhibit the unusual trait of two-colour (red and green) multiexcitonic emission, with green emission from the CdS arms emerging only at high excitation fluences. Here we show that by synthetic shape-tuning, both this multi-colour emission process, and blinking and photobleaching behaviours of single tetrapods can be controlled. Specifically, we find that the properties of dual emission and single-nanostructure photostability depend on different structural parameters—arm length and arm diameter, respectively—but that both properties can be realized in the same nanostructure. Furthermore, based on results of correlated photoluminescence and transient absorption measurements, we conclude that hole-trap filling in the arms and partial state-filling in the core are necessary preconditions for the observation of multiexciton multi-colour emission. PMID:28497776

Imaging Organ of Corti Vibration Using Fourier-Domain OCT

NASA Astrophysics Data System (ADS)

Choudhury, Niloy; Chen, Fangyi; Fridberger, Anders; Zha, Dingjun; Jacques, Steven L.; Wang, Ruikang K.; Nuttall, Alfred L.

2011-11-01

Measuring the sound stimulated vibration from various structures in the organ of Corti is important in understanding how the small vibrations are amplified and detected. In this study we examine the feasibility of using phase-sensitive Fourier domain optical coherence tomography (PSFD-OCT) to measure vibration of the cellular structures of the organ of Corti. PSFD-OCT is a low coherence interferrometry system where the interferrogram is detected as a function of wavelength. The phase of the Fourier transformation of the detected spectra contains path deference (between the sample arm and the reference arm) information of the interferometer. In PSFD-OCT this phase is measured as a function of time and thus any time dependent change in the path difference between the sample arm and the reference arm can be detected. In the experiment, we used an in vitro preparation of the guinea pig cochlea and made a surgical opening at the apical end to access the organ of Corti. By applying tones with different frequencies via the intact middle ear, we recorded the structural vibration inside the organ of Corti. Vibration amplitude and phase of different substructures were mapped on a cross-section view of the organ of Corti. Although the measurements were made at the apical turn of the cochlea, it will be possible to make vibration measurement from various turns of the cochlea. The noise floor of the system was 0.3 nm, calibrated using a piezo stack as a calibrator.

Association of objectively measured arm inclination with shoulder pain: A 6-month follow-up prospective study of construction and health care workers.

PubMed

Koch, Markus; Lunde, Lars-Kristian; Veiersted, Kaj Bo; Knardahl, Stein

2017-01-01

The aim was to determine the association of occupational arm inclination with shoulder pain in construction and health care workers. Arm inclination relative to the vertical was measured with an accelerometer placed on the dominant upper arm for up to four full days at baseline in 62 construction workers and 63 health care workers. The pain intensity in the shoulder and mechanical and psychosocial work factors were measured by self-reports at baseline and prospectively after 6 months. The associations between exposures and shoulder pain were analyzed with multilevel mixed-effects linear regressions. For the total study population working with the dominant arm at inclinations > 30° and >120° was associated with lower levels of shoulder pain both cross-sectionally and after 6 months. Associations were attenuated when adjusting for individual and social factors, psychological state, and exposure during leisure time, especially for the high inclination levels. Analyses, only including subjects with no pain at baseline revealed no significant associations. While stratified analysis showed negative associations in the construction worker group, there were no significant association in health care workers. Compared to the number of hypotheses tested, the number of significant findings was low. Adjustment by Bonferroni-correction made almost all findings insignificant. All analyses reflected a negative association between arm inclination and shoulder pain, but few analyses showed these associations to be statistically significant. If there is a relationship between arm inclination and shoulder pain, these findings could indicate that pain-avoidance may modify how workers perform their tasks.

Loss of 11q and 16q in Wilms tumors is associated with anaplasia, tumor recurrence, and poor prognosis.

PubMed

Wittmann, Stefanie; Zirn, Birgit; Alkassar, Muhannad; Ambros, Peter; Graf, Norbert; Gessler, Manfred

2007-02-01

Allele loss of chromosome arms 11q and 16q in Wilms tumors has been associated with different clinical parameters in prior studies. To substantiate these findings in a large collection of tumors treated according to the GPOH/SIOP protocol and to narrow down critical regions, we performed loss of heterozygosity (LOH) analyses of chromosome arms 11q and 16q on 225 Wilms tumors. On chromosome arm 11q an overall rate of allele loss of 19.6% (44 of 225 tumors) was found using eleven markers that were almost evenly distributed along the long arm. Chromosome arm 16q was analyzed with six markers selected from gene-rich regions that identified an LOH rate of 18.4% (41/223). Evaluation of LOH with respect to clinical data revealed significant associations of LOH 11q with histology: LOH 11q was 3-4 times more frequent in mixed type and diffuse anaplastic tumors. In contrast, epithelial as well as stromal type tumors never exhibited allele loss on 11q. Furthermore, a significant correlation with tumor recurrence and death was detected, but only for tumors that lost the entire long arm of chromosome 11. Similarly, LOH 16q was correlated with higher risks of later relapse, especially in tumors with complete loss of the long arm. Hence, analyses of LOH on 11q and 16q appear to be helpful to identify tumors with a higher risk of relapse and adverse outcome, which need adjusted therapeutic approaches. Copyright 2006 Wiley-Liss, Inc.

Association of objectively measured arm inclination with shoulder pain: A 6-month follow-up prospective study of construction and health care workers

PubMed Central

Koch, Markus; Lunde, Lars-Kristian; Veiersted, Kaj Bo; Knardahl, Stein

2017-01-01

Objectives The aim was to determine the association of occupational arm inclination with shoulder pain in construction and health care workers. Methods Arm inclination relative to the vertical was measured with an accelerometer placed on the dominant upper arm for up to four full days at baseline in 62 construction workers and 63 health care workers. The pain intensity in the shoulder and mechanical and psychosocial work factors were measured by self-reports at baseline and prospectively after 6 months. The associations between exposures and shoulder pain were analyzed with multilevel mixed-effects linear regressions. Results For the total study population working with the dominant arm at inclinations > 30° and >120° was associated with lower levels of shoulder pain both cross-sectionally and after 6 months. Associations were attenuated when adjusting for individual and social factors, psychological state, and exposure during leisure time, especially for the high inclination levels. Analyses, only including subjects with no pain at baseline revealed no significant associations. While stratified analysis showed negative associations in the construction worker group, there were no significant association in health care workers. Compared to the number of hypotheses tested, the number of significant findings was low. Adjustment by Bonferroni-correction made almost all findings insignificant. Conclusions All analyses reflected a negative association between arm inclination and shoulder pain, but few analyses showed these associations to be statistically significant. If there is a relationship between arm inclination and shoulder pain, these findings could indicate that pain-avoidance may modify how workers perform their tasks. PMID:29176761

Plasma BDNFs level initially and post treatment in acute mania: comparison between ECT and atypical antipsychotic treatment and healthy controls.

PubMed

Karamustafalioglu, Nesrin; Genc, Abdullah; Kalelioglu, Tevfik; Tasdemir, Akif; Umut, Gokhan; Incir, Said; Akkuş, Mustafa; Emul, Murat

2015-08-01

Inconsistent findings concerning brain-derived neurotrophic factor (BDNF) levels across different episodes in bipolar disorder have been reported, which is also in line with the treatment effects on BDNF levels in acute mania. We aimed to compare plasma BDNF level alterations after pure antipsychotic drug or ECT plus antipsychotic drug treatment in acute mania. Sixty-eight patients with mania were divided into two treatment arms: the antipsychotic treatment arm (AP) and electroconvulsive therapy (ECT)+AP arm. In addition, 30 healthy controls were included in the study. There was no significant statistical difference according to mean age, education level, marital and working status between patients and healthy controls. The initial serum BDNF level in patients with acute mania was significantly lower than healthy controls. The initial BDNF level between the ECT arm and AP arm was not significant. The BDNF level decreased significantly after reaching remission in patients with acute mania. The change in BDNF level in the AP arm was not significant while in the ECT arm it was significant after treatment. In this study, for the first time we revealed a significant decrease in BDNF levels after ECT sessions in acute manic patients. Besides clinical remission after treatment in acute mania, the decrement in BDNF levels does not seem to be related to clinical response. Thus cumulative effects of mood episodes for the ongoing decrease in BDNF levels might be borne in mind despite the achievement of remission and/or more time being required for an increase in BDNF levels after treatment. © The Author(s) 2015.

Modal kinematics for multisection continuum arms.

PubMed

Godage, Isuru S; Medrano-Cerda, Gustavo A; Branson, David T; Guglielmino, Emanuele; Caldwell, Darwin G

2015-05-13

This paper presents a novel spatial kinematic model for multisection continuum arms based on mode shape functions (MSF). Modal methods have been used in many disciplines from finite element methods to structural analysis to approximate complex and nonlinear parametric variations with simple mathematical functions. Given certain constraints and required accuracy, this helps to simplify complex phenomena with numerically efficient implementations leading to fast computations. A successful application of the modal approximation techniques to develop a new modal kinematic model for general variable length multisection continuum arms is discussed. The proposed method solves the limitations associated with previous models and introduces a new approach for readily deriving exact, singularity-free and unique MSF's that simplifies the approach and avoids mode switching. The model is able to simulate spatial bending as well as straight arm motions (i.e., pure elongation/contraction), and introduces inverse position and orientation kinematics for multisection continuum arms. A kinematic decoupling feature, splitting position and orientation inverse kinematics is introduced. This type of decoupling has not been presented for these types of robotic arms before. The model also carefully accounts for physical constraints in the joint space to provide enhanced insight into practical mechanics and impose actuator mechanical limitations onto the kinematics thus generating fully realizable results. The proposed method is easily applicable to a broad spectrum of continuum arm designs.

Origin of the Blytheville Arch, and long-term displacement on the New Madrid seismic zone, central United States

USGS Publications Warehouse

Pratt, Thomas L.; Williams, Robert; Odum, Jackson K.; Stephenson, William J.

2013-01-01

The southern arm of the New Madrid seismic zone of the central United States coincides with the buried, ~110 km by ~20 km Blytheville Arch antiform within the Cambrian–Ordovician Reelfoot rift graben. The Blytheville Arch has been interpreted at various times as a compressive structure, an igneous intrusion, or a sediment diapir. Reprocessed industry seismic-reflection profiles presented here show a strong similarity between the Blytheville Arch and pop-up structures, or flower structures, within strike-slip fault systems. The Blytheville Arch formed in the Paleozoic, but post–Mid-Cretaceous to Quaternary strata show displacement or folding indicative of faulting. Faults within the graben structure but outside of the Blytheville Arch also appear to displace Upper Cretaceous and perhaps younger strata, indicating that past faulting was not restricted to the Blytheville Arch and New Madrid seismic zone. As much as 10–12.5 km of strike slip can be estimated from apparent shearing of the Reelfoot arm of the New Madrid seismic zone. There also appears to be ~5–5.5 km of shearing of the Reelfoot topographic scarp at the north end of the southern arm of the New Madrid seismic zone and of the southern portion of Crowley's Ridge, which is a north-trending topographic ridge just south of the seismic zone. These observations suggest that there has been substantial strike-slip displacement along the Blytheville Arch and southern arm of the New Madrid seismic zone, that strike-slip extended north and south of the modern seismic zone, and that post–Mid-Cretaceous (post-Eocene?) faulting was not restricted to the Blytheville Arch or to currently active faults within the New Madrid seismic zone.

Phenotypic Mismatches Reveal Escape from Arms-Race Coevolution

PubMed Central

Hanifin, Charles T; Brodie, Edmund D; Brodie, Edmund D

2008-01-01

Because coevolution takes place across a broad scale of time and space, it is virtually impossible to understand its dynamics and trajectories by studying a single pair of interacting populations at one time. Comparing populations across a range of an interaction, especially for long-lived species, can provide insight into these features of coevolution by sampling across a diverse set of conditions and histories. We used measures of prey traits (tetrodotoxin toxicity in newts) and predator traits (tetrodotoxin resistance of snakes) to assess the degree of phenotypic mismatch across the range of their coevolutionary interaction. Geographic patterns of phenotypic exaggeration were similar in prey and predators, with most phenotypically elevated localities occurring along the central Oregon coast and central California. Contrary to expectations, however, these areas of elevated traits did not coincide with the most intense coevolutionary selection. Measures of functional trait mismatch revealed that over one-third of sampled localities were so mismatched that reciprocal selection could not occur given current trait distributions. Estimates of current locality-specific interaction selection gradients confirmed this interpretation. In every case of mismatch, predators were “ahead” of prey in the arms race; the converse escape of prey was never observed. The emergent pattern suggests a dynamic in which interacting species experience reciprocal selection that drives arms-race escalation of both prey and predator phenotypes at a subset of localities across the interaction. This coadaptation proceeds until the evolution of extreme phenotypes by predators, through genes of large effect, allows snakes to, at least temporarily, escape the arms race. PMID:18336073

Galactic Spiral Shocks with Thermal Instability in Vertically Stratified Galactic Disks

NASA Astrophysics Data System (ADS)

Kim, Chang-Goo; Kim, Woong-Tae; Ostriker, Eve C.

2010-09-01

Galactic spiral shocks are dominant morphological features and believed to be responsible for substructure formation within spiral arms in disk galaxies. They can also contribute a substantial amount of kinetic energy to the interstellar gas by tapping the (differential) rotational motion. We use numerical hydrodynamic simulations to investigate dynamics and structure of spiral shocks with thermal instability (TI) in vertically stratified galactic disks, focusing on environmental conditions (of heating and the galactic potential) similar to the Solar neighborhood. We initially consider an isothermal disk in vertical hydrostatic equilibrium and let it evolve subject to interstellar cooling and heating as well as a stellar spiral potential. Due to TI, a disk with surface density Σ0 >= 6.7 M sun pc-2 rapidly turns to a thin dense slab near the midplane sandwiched between layers of rarefied gas. The imposed spiral potential leads to a vertically curved shock that exhibits strong flapping motions in the plane perpendicular to the arm. The overall flow structure at saturation is comprised of the arm, postshock expansion zone, and interarm regions that occupy typically 10%, 20%, and 70% of the arm-to-arm distance, in which the gas resides for 15%, 30%, and 55% of the arm-to-arm crossing time, respectively. The flows are characterized by transitions from rarefied to dense phases at the shock and from dense to rarefied phases in the postshock expansion zone, although gas with too-large postshock-density does not undergo this return phase transition, instead forming dense condensations. If self-gravity is omitted, the shock flapping drives random motions in the gas, but only up to ~2-3 km s-1 in the in-plane direction and less than 2 km s-1 in the vertical direction. Time-averaged shock profiles show that the spiral arms in stratified disks are broader and less dense compared to those in unstratified models, and that the vertical density distribution is overall consistent with local effective hydrostatic equilibrium. Inclusion of self-gravity increases the dense gas fraction by a factor of ~2 and raises the in-plane velocity dispersion to ~5-7 km s-1. When the disks are massive enough, with Σ0 >= 5 M sun pc-2, self-gravity promotes formation of bound clouds that repeatedly collide with each other in the arm and break up in the postshock expansion zone.

PPP2R1A regulated by PAX3/FOXO1 fusion contributes to the acquisition of aggressive behavior in PAX3/FOXO1-positive alveolar rhabdomyosarcoma.

PubMed

Akaike, Keisuke; Suehara, Yoshiyuki; Kohsaka, Shinji; Hayashi, Takuo; Tanabe, Yu; Kazuno, Saiko; Mukaihara, Kenta; Toda-Ishii, Midori; Kurihara, Taisei; Kim, Youngji; Okubo, Taketo; Hayashi, Yasuhide; Takamochi, Kazuya; Takahashi, Fumiyuki; Kaneko, Kazuo; Ladanyi, Marc; Saito, Tsuyoshi

2018-05-18

To better characterize the oncogenic role of the PAX3-FOXO1 fusion protein in the acquisition of aggressive behavior in ARMS, we employed a proteomic approach using a PAX3-FOXO1 knockdown system in ARMS cell lines. This approach revealed a protein list consisting of 107 consistently upregulated and 114 consistently downregulated proteins that were expected to be regulated by PAX3-FOXO1 fusion protein. Furthermore, we identified 16 upregulated and 17 downregulated critical proteins based on a data-mining analysis. We also evaluated the function of PPP2R1A in ARMS cells. The PPP2R1A expression was upregulated at both the mRNA and protein levels by PAX3-FOXO1 silencing. The silencing of PPP2R1A significantly increased the cell growth of all four ARMS cells, suggesting that PPP2R1A still has a tumor suppressive function in ARMS cells; however, the native expression of PPP2R1A was low in the presence of PAX3-FOXO1. In addition, the activation of PP2A-part of which was encoded by PPP2R1A -by FTY720 treatment in ARMS cell lines inhibited cell growth. On the human phospho-kinase array analysis of 46 specific Ser/Thr or Tyr phosphorylation sites on 39 selected proteins, eNOS, AKT1/2/3, RSK1/2/3 and STAT3 phosphorylation were decreased by FTY-720 treatment. These findings suggest that PPP2R1A is a negatively regulated by PAX3-FOXO1 in ARMS. The activation of PP2A-probably in combination with kinase inhibitors-may represent a therapeutic target in ARMS. We believe that the protein expression profile associated with PAX3-FOXO1 would be valuable for discovering new therapeutic targets in ARMS.

Myofascial Induction Effects on Neck-Shoulder Pain in Breast Cancer Survivors: Randomized, Single-Blind, Placebo-Controlled Crossover Design.

PubMed

Castro-Martín, Eduardo; Ortiz-Comino, Lucía; Gallart-Aragón, Tania; Esteban-Moreno, Bernabé; Arroyo-Morales, Manuel; Galiano-Castillo, Noelia

2017-05-01

To (1) investigate the immediate effects of myofascial induction (MI), with placebo electrotherapy as a control, on perceived pain, cervical/shoulder range of motion (ROM), and mood state in breast cancer survivors (BCSs) with shoulder/arm morbidity; and (2) examine the relationships between pain modifications and cervical/shoulder ROM on the side affected by breast cancer. Randomized, single-blind, placebo-controlled crossover study. Physical therapy laboratory. BCSs (N=21) who had a diagnosis of stage I-IIIA breast cancer and had completed adjuvant therapy (except hormonal treatment). During each session, the BCSs received either an MI (fascial unwinding) intervention focused on the upper limb area following the Pilat approach or placebo pulsed shortwave therapy (control group). Each session lasted 30 minutes, and an adequate washout period of 4 weeks between sessions was established. The visual analog scale (VAS) for pain and anxiety, shoulder-cervical goniometry for ROM, the Profile of Mood States for psychological distress, and the Attitudes Towards Massage Scale were used. An analysis of covariance (ANCOVA) revealed significant time × group interactions for VAS affected arm (P=.031) but not for VAS cervical (P=.332), VAS nonaffected arm (P=.698), or VAS anxiety (P=.266). The ANCOVA also revealed significant interactions for affected shoulder flexion (P<.001), abduction (P<.001), external rotation (P=.004), and internal rotation (P=.001). Significant interactions for affected cervical rotation (P=.022) and affected cervical lateral flexion (P=.038) were also found. A significant negative correlation was found between changes in VAS affected arm and shoulder/arm internal rotation ROM (r=-.46; P=.03). A single MI session decreases pain intensity and improves neck-shoulder ROM to a greater degree than placebo electrotherapy for BCSs experiencing pain. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Curiosity Leaves Its Mark

NASA Image and Video Library

2012-08-29

This image shows a close-up of track marks from the first test drive of NASA Curiosity rover. The rover arm is visible in the foreground. A close inspection of the tracks reveals a unique, repeating pattern: Morse code for JPL.

ARM AND INTERARM STAR FORMATION IN SPIRAL GALAXIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foyle, K.; Rix, H.-W.; Walter, F.

2010-12-10

We investigate the relationship between spiral arms and star formation in the grand-design spirals NGC 5194 and NGC 628 and in the flocculent spiral NGC 6946. Filtered maps of near-IR (3.6 {mu}m) emission allow us to identify 'arm regions' that should correspond to regions of stellar mass density enhancements. The two grand-design spirals show a clear two-armed structure, while NGC 6946 is more complex. We examine these arm and interarm regions, looking at maps that trace recent star formation-far-ultraviolet (GALEX NGS) and 24 {mu}m emission (Spitzer SINGS)-and cold gas-CO (HERACLES) and H I (THINGS). We find the star formation tracersmore » and CO more concentrated in the spiral arms than the stellar 3.6 {mu}m flux. If we define the spiral arms as the 25% highest pixels in the filtered 3.6 {mu}m images, we find that the majority (60%) of star formation tracers occur in the interarm regions; this result persists qualitatively even when considering the potential impact of finite data resolution and diffuse interarm 24 {mu}m emission. Even with a generous definition of the arms (45% highest pixels), interarm regions still contribute at least 30% to the integrated star formation rate (SFR) tracers. We look for evidence that spiral arms trigger star or cloud formation using the ratios of SFR (traced by a combination of FUV and 24 {mu}m emission) to H{sub 2} (traced by CO) and H{sub 2} to H I. Any enhancement of SFR/M(H{sub 2}) in the arm region is very small (less than 10%) and the grand-design spirals show no enhancement compared to the flocculent target. Arm regions do show a weak enhancement in H{sub 2}/H I compared to the interarm regions, but at a fixed gas surface density there is little clear enhancement in the H{sub 2}/H I ratio in the arm regions. Thus, it seems that spiral arms may only act to concentrate the gas to higher densities in the arms.« less

Multi-organ dysfunction in bodybuilding possibly caused by prolonged hypercalcemia due to multi-substance abuse: case report and review of literature.

PubMed

Schäfer, C N; Guldager, H; Jørgensen, H L

2011-01-01

A 26-year-old male bodybuilder was admitted to the surgical department of a Danish community hospital for hematemesis. During the clinical interview, he revealed that he had recently finished a course of anabolic steroids and erythropoietin. The patient also had a previous history of infections and chronic ulcers due to paraffin-oil injections in both upper arms one year before. Over the course of the next few hours, the patient developed signs of multi-organ dysfunction, including pancreatitis, hemorrhagic gastritis, nephropathy with temporary anuria, and respiratory insufficiency, and was transferred to the ICU. After manometric monitoring on the patient's upper arms proved difficult, invasive blood pressure monitoring was used and revealed that the patient was in a state of hypertensive crisis. This case of multi-organ dysfunction was possibly caused by multi-substance-induced hypercalcemia. © Georg Thieme Verlag KG Stuttgart · New York.

Man-In-The-Barrel. A Case of Cervical Spinal Cord Infarction and Review of the Literature

PubMed Central

Antelo, María José García; Facal, Teresa Lema; Sánchez, Tamara Pablos; Facal, María Soledad López; Nazabal, Eduardo Rubio

2013-01-01

Introduction: Man-in-the-barrel syndrome was initially observed in patients with signs of serious cerebral hypoperfusion, in the border zone of the anterior and medial cerebral artery, but other causes were communicated later. Methods: a healthy 43-year-old woman who showed intense cervical pain, irradiating over both shoulders and arms. Physical examination on admission highlighted notable brachial diparesis, tacto-algesic hypoesthesia of both arms and sensory level C4-D9. Results: cervical Magnetic Resonance Imaging (MRI) on admission revealed a hyperintense intramedullar lesion at C3-C7 level, due to a cervical cord infarction. Conclusions: our case reveals that conventional neurological consideration about the specific anatomical location of man-in-the-barrel syndrome in the brain should be extended to other locations such as the cervical column and not only the brain area. PMID:23407685

Elucidation of the mechanism of homozygous deletion of 3p12-13 in the U2020 cell line reveals the unexpected involvement of other chromosomes.

PubMed

Heppell-Parton, A C; Nacheva, E; Carter, N P; Bergh, J; Ogilvie, D; Rabbitts, P H

1999-06-01

Homozygous deletions in tumor cells have been useful in the localization and validation of tumor suppressor genes. We have described a homozygous deletion in a lung cancer cell line (U2020) which is located within the most proximal of the three regions on the short arm of chromosome 3 believed to be lost in lung cancer development. Construction of a YAC contig map indicates that the deletion spans around 8 Mb, but no large deletion was apparent on conventional cytogenetic analysis of the cell line. To investigate this paradox, whole chromosome, arm-specific, and regional paints have been used. This analysis has revealed that genetic loss has occurred by complex rearrangements of chromosomes 3, rather than simple interstitial deletion. These studies emphasize the power of molecular cytogenetics to disclose unsuspected tumor-specific translocations within the extremely complex karyotypes characteristic of solid tumors.

Stochastic Estimation of Arm Mechanical Impedance During Robotic Stroke Rehabilitation

PubMed Central

Palazzolo, Jerome J.; Ferraro, Mark; Krebs, Hermano Igo; Lynch, Daniel; Volpe, Bruce T.; Hogan, Neville

2009-01-01

This paper presents a stochastic method to estimate the multijoint mechanical impedance of the human arm suitable for use in a clinical setting, e.g., with persons with stroke undergoing robotic rehabilitation for a paralyzed arm. In this context, special circumstances such as hypertonicity and tissue atrophy due to disuse of the hemiplegic limb must be considered. A low-impedance robot was used to bring the upper limb of a stroke patient to a test location, generate force perturbations, and measure the resulting motion. Methods were developed to compensate for input signal coupling at low frequencies apparently due to human–machine interaction dynamics. Data was analyzed by spectral procedures that make no assumption about model structure. The method was validated by measuring simple mechanical hardware and results from a patient's hemiplegic arm are presented. PMID:17436881

Simulation of cooperating robot manipulators on a mobile platform

NASA Technical Reports Server (NTRS)

Murphy, Stephen H.; Wen, John Ting-Yung; Saridis, George N.

1991-01-01

The dynamic equations of motion are presented for two or more cooperating manipulators on a freely moving mobile platform. The system of cooperating robot manipulators forms a closed kinematic chain where the force of interaction must be included in the formulation of robot and platform dynamics. The formulation includes the full dynamic interactions from arms to platform and arm tip to arm tip, and the possible translation and rotation of the platform. The equations of motion are shown to be identical in structure to the fixed-platform cooperative manipulator dynamics. The number of DOFs of the system is sufficiently large to make recursive dynamic calculation methods potentially more efficient than closed-form solutions. A complete simulation with two 6-DOF manipulators of a free-floating platform is presented along a with a multiple-arm controller to position the common load.

Phoenix's 'Dodo' Trench

NASA Technical Reports Server (NTRS)

2008-01-01

This image was taken by NASA's Phoenix Mars Lander's Robotic Arm Camera (RAC) on the ninth Martian day of the mission, or Sol 9 (June 3, 2008). The center of the image shows a trench informally called 'Dodo' after the second dig. 'Dodo' is located within the previously determined digging area, informally called 'Knave of Hearts.' The light square to the right of the trench is the Robotic Arm's Thermal and Electrical Conductivity Probe (TECP). The Robotic Arm has scraped to a bright surface which indicated the Arm has reached a solid structure underneath the surface, which has been seen in other images as well.

The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

The Effects of Disaster on Women's Reproductive Health in Developing Countries

PubMed Central

Swatzyna, Ronald J.; Pillai, Vijayan K.

2013-01-01

The objective of this study is to empirically test the effects of disasters which include natural as well as human made disasters such as armed conflict on women's reproductive health in developing countries. Data from 128 developing countries are used. It was found that average number of deaths from natural disasters and armed conflict in the East Asia and Pacific region was not significantly different from the rest of the developing world. The data are examined using structural equation analysis. This study finds that ‘armed conflict’ in developing countries presents significant reproductive health risks. The implications are discussed. PMID:23777727

Real-Time Decentralized Neural Control via Backstepping for a Robotic Arm Powered by Industrial Servomotors.

PubMed

Vazquez, Luis A; Jurado, Francisco; Castaneda, Carlos E; Santibanez, Victor

2018-02-01

This paper presents a continuous-time decentralized neural control scheme for trajectory tracking of a two degrees of freedom direct drive vertical robotic arm. A decentralized recurrent high-order neural network (RHONN) structure is proposed to identify online, in a series-parallel configuration and using the filtered error learning law, the dynamics of the plant. Based on the RHONN subsystems, a local neural controller is derived via backstepping approach. The effectiveness of the decentralized neural controller is validated on a robotic arm platform, of our own design and unknown parameters, which uses industrial servomotors to drive the joints.

Differentiation and Evolution of the W Chromosome in the Fish Species of Megaleporinus (Characiformes, Anostomidae).

PubMed

Caetano de Barros, Lucas; Piscor, Diovani; Parise-Maltempi, Patricia P; Feldberg, Eliana

2018-06-08

The W chromosome of Megaleporinus trifasciatus was isolated in order to analyze its behavior in the karyotype of this and other species of the family, including forms with differentiated and undifferentiated sex chromosomes. The chromosome was microdissected, and the WMt probe was prepared for the chromosome painting procedure. M. trifasciatus was also cross-hybridized (cross-FISH) using existing probes available for M. macrocephalus (WMm) and M. elongatus (WMe). Two Leporinus species and Semaprochilodus taeniurus, representing a clade close to the Anostomidae, were also cross-hybridized with the objective to better understand the evolution of the sex chromosomes. In the metaphase of female M. trifasciatus, the WMt probe highlighted the whole long arm of the W chromosome and a small, distal portion of the long arm of the Z chromosome. In males, the probe highlighted the distal portion of the long arm of the Z chromosomes. The hybridization of female M. trifasciatus with the WMe and WMm probes revealed a pattern similar to that encountered using the WMt probe. The WMt, WMm, and WMe probes revealed broad similarities among the species of the genus Megaleporinus, which has a ZZ/ZW system of sex chromosomes, with only minor alterations becoming apparent when analyzed separately. © 2018 S. Karger AG, Basel.

Cryptic insertion of 3'FOXO1 into inverted chromosome arm 2q in the presence of two normal chromosome 13s and 13 small interstitial duplications in a patient with alveolar rhabdomyosarcoma.

PubMed

Hackman, Sarah; Calvey, Laura; Bernreuter, Kristen; Mark, Mengya Wang; Starnes, Sarah; Batanian, Jacqueline R

2015-09-01

Alveolar rhabdomyosarcoma (ARMS) is a pediatric soft tissue neoplasm with a characteristic translocation, t(2;13)(q35;q14), which is detected in 70-80% of cases. This well-described translocation produces the gene fusion product PAX3-FOXO1. Cryptic rearrangements of this fusion have never before been reported in ARMS. Here we describe a patient with ARMS that showed, by fluorescence in situ hybridization and G-banded chromosomes, a cryptic insertion of 3'FOXO1 into inverted chromosome 2q. The inversion breakpoints were depicted by array comparative genomic hybridization as two small interstitial duplications, one of which involved the PAX3 gene. In addition, the array comparative genomic hybridization results revealed 1q gain, 16q loss, and 11 more small duplications, with one of them involving the FOXO1 gene. Although the pathogenesis in classic ARMS cases is thought to be driven by the 5'PAX3-3'FOXO1 fusion on derivative chromosome 13, here we report a novel cryptic insertion of 3'FOXO1 resulting in a pathogenic fusion with 5'PAX3 on inverted chromosome 2q. Copyright © 2015 Elsevier Inc. All rights reserved.

Reliability of Achilles Tendon Moment Arm Measured In Vivo Using Freehand Three-Dimensional Ultrasound.

PubMed

Obst, Steven J; Barber, Lee; Miller, Ashton; Barrett, Rod S

2017-08-01

This study investigated reliability of freehand three-dimensional ultrasound (3DUS) measurement of in vivo human Achilles tendon (AT) moment arm. Sixteen healthy adults were scanned on 2 separate occasions by a single investigator. 3DUS scans were performed over the free AT, medial malleolus, and lateral malleolus with the ankle passively positioned in maximal dorsiflexion, mid dorsiflexion, neutral, mid plantar flexion and maximal plantar flexion. 3D reconstructions of the AT, medial malleolus, and lateral malleolus were created from manual segmentation of the ultrasound images and used to geometrically determine the AT moment arm using both a straight (straight AT MA ) and curved (curved AT MA ) tendon line-of-action. Both methods were reliable within- and between-session (intra-class correlation coefficients > 0.92; coefficient of variation < 2.5 %) and revealed that AT moment arm increased by ∼ 7 mm from maximal dorsiflexion (∼ 41mm) to maximal plantar flexion (∼ 48 mm). Failing to account for tendon curvature led to a small overestimation (< 2 mm) of AT moment arm that was most pronounced in ankle plantar flexion, but was less than the minimal detectable change of the method and could be disregarded.

The Hexamer Structure of the Rift Valley Fever Virus Nucleoprotein Suggests a Mechanism for its Assembly into Ribonucleoprotein Complexes

PubMed Central

Ferron, François; Li, Zongli; Danek, Eric I.; Luo, Dahai; Wong, Yeehwa; Coutard, Bruno; Lantez, Violaine; Charrel, Rémi; Canard, Bruno; Walz, Thomas; Lescar, Julien

2011-01-01

Rift Valley fever virus (RVFV), a Phlebovirus with a genome consisting of three single-stranded RNA segments, is spread by infected mosquitoes and causes large viral outbreaks in Africa. RVFV encodes a nucleoprotein (N) that encapsidates the viral RNA. The N protein is the major component of the ribonucleoprotein complex and is also required for genomic RNA replication and transcription by the viral polymerase. Here we present the 1.6 Å crystal structure of the RVFV N protein in hexameric form. The ring-shaped hexamers form a functional RNA binding site, as assessed by mutagenesis experiments. Electron microscopy (EM) demonstrates that N in complex with RNA also forms rings in solution, and a single-particle EM reconstruction of a hexameric N-RNA complex is consistent with the crystallographic N hexamers. The ring-like organization of the hexamers in the crystal is stabilized by circular interactions of the N terminus of RVFV N, which forms an extended arm that binds to a hydrophobic pocket in the core domain of an adjacent subunit. The conformation of the N-terminal arm differs from that seen in a previous crystal structure of RVFV, in which it was bound to the hydrophobic pocket in its own core domain. The switch from an intra- to an inter-molecular interaction mode of the N-terminal arm may be a general principle that underlies multimerization and RNA encapsidation by N proteins from Bunyaviridae. Furthermore, slight structural adjustments of the N-terminal arm would allow RVFV N to form smaller or larger ring-shaped oligomers and potentially even a multimer with a super-helical subunit arrangement. Thus, the interaction mode between subunits seen in the crystal structure would allow the formation of filamentous ribonucleocapsids in vivo. Both the RNA binding cleft and the multimerization site of the N protein are promising targets for the development of antiviral drugs. PMID:21589902

Randomized controlled trial of a dose consolidation program.

PubMed

Delate, Thomas; Fairman, Kathleen A; Carey, Shelly M; Motheral, Brenda R

2004-01-01

To evaluate the effectiveness and financial impact of a drug dose consolidation (optimization) program using letter intervention. This pilot program in a large, mid-Atlantic health plan utilized a randomized controlled trial research design. A review of adjudicated pharmacy claims records was performed monthly for 3 consecutive months from November 2002 through February 2003 to identify inefficient (i.e., >once-daily) regimens for any one of 68 dosage strengths of 37 single-source maintenance drugs with once-daily dosing recommendations. Prescribers who had prescribed one or more inefficient regimens were identified and randomized to one of the 2 intervention arms or a control arm. Prescribers in both intervention arms were sent personalized letters with information on their patients. inefficient regimens and suggested dose consolidation options. Patients of prescribers in one intervention arm received a complementary, patient-oriented letter. Pharmacy claims for patients in all arms were examined at 180 days after the date of the letter mailing for conversion to an efficient (once-daily) regimen. Financial modeling analysis calculated net savings as changes in pharmacy expenditures minus administrative costs. A total of 2,614 inefficient regimens, representing 6.7% of claims for the targeted medications, were identified. The rate of consolidation to a suggested dosing option was lower for the Physician Letter arm (7.3%) than for the Physician/Member Letter arm (10.2%) (P = 0.046). Both intervention arms had higher consolidation rates than the Control arm (3.9%) (P = 0.018 and P = 0.000, respectively.). Approximately 30% of the regimens in each study arm were never refilled after being targeted. Financial modeling indicated that a dose consolidation intervention could save 0.03 dollars to 0.07 dollars per member per month (PMPM) in 2003 dollars with full medication compliance but only 0.02 dollars to 0.03 dollars PMPM when savings were calculated with realistic, partial compliance rates. Subanalyses performed at the drug therapy class level revealed few opportunities to justify implementing a dose consolidation program. After taking into consideration program administrative costs, high rates of refill discontinuation, and dose consolidation that occurs naturally without intervention, the results indicated that a letter-based dose consolidation program did not appreciably decrease pharmacy expenditures.

Gaming and Conventional Exercises for Improvement of Arm Function After Stroke: A Randomized Controlled Pilot Study.

PubMed

Kottink, Anke I R; Prange, Gerdienke B; Krabben, Thijs; Rietman, Johan S; Buurke, Jaap H

2014-06-01

The use of new technologies in rehabilitation, such as virtual reality and/or computerized gaming exercises, may be useful to enable patients to practice intensively in a motivating way. The objective of the present randomized controlled pilot study was to compare the effect of reach training using a target group specific-designed rehabilitation game to time-matched standardized conventional reach training on arm function after stroke. Twenty chronic stroke patients were randomized to either the rehabilitation game group or the conventional training group. Both groups received three arm training sessions of 30 minutes each week, during a period of 6 weeks. Arm (the upper extremity part of Fugl-Meyer [FM] assessment) and hand (the Action Research Arm [ARA] test) functions were tested 1 week before (T0) and 1 week after (T1) training. A follow-up measurement was performed at 1 month after T1 (T2). ARA and FM scores improved significantly within both groups. Post hoc comparisons revealed significant increases in test scores between T0 and T1 and between T0 and T2 for both ARA and FM, but not for changes from T1 to T2. There were no significant differences between both groups for either clinical test. The present randomized controlled pilot study showed that both arm and hand function improved as much after training with a rehabilitation game as after time-matched conventional training.

Armed-conflict risks enhanced by climate-related disasters in ethnically fractionalized countries.

PubMed

Schleussner, Carl-Friedrich; Donges, Jonathan F; Donner, Reik V; Schellnhuber, Hans Joachim

2016-08-16

Social and political tensions keep on fueling armed conflicts around the world. Although each conflict is the result of an individual context-specific mixture of interconnected factors, ethnicity appears to play a prominent and almost ubiquitous role in many of them. This overall state of affairs is likely to be exacerbated by anthropogenic climate change and in particular climate-related natural disasters. Ethnic divides might serve as predetermined conflict lines in case of rapidly emerging societal tensions arising from disruptive events like natural disasters. Here, we hypothesize that climate-related disaster occurrence enhances armed-conflict outbreak risk in ethnically fractionalized countries. Using event coincidence analysis, we test this hypothesis based on data on armed-conflict outbreaks and climate-related natural disasters for the period 1980-2010. Globally, we find a coincidence rate of 9% regarding armed-conflict outbreak and disaster occurrence such as heat waves or droughts. Our analysis also reveals that, during the period in question, about 23% of conflict outbreaks in ethnically highly fractionalized countries robustly coincide with climatic calamities. Although we do not report evidence that climate-related disasters act as direct triggers of armed conflicts, the disruptive nature of these events seems to play out in ethnically fractionalized societies in a particularly tragic way. This observation has important implications for future security policies as several of the world's most conflict-prone regions, including North and Central Africa as well as Central Asia, are both exceptionally vulnerable to anthropogenic climate change and characterized by deep ethnic divides.

Interface evaluation for soft robotic manipulators

NASA Astrophysics Data System (ADS)

Moore, Kristin S.; Rodes, William M.; Csencsits, Matthew A.; Kwoka, Martha J.; Gomer, Joshua A.; Pagano, Christopher C.

2006-05-01

The results of two usability experiments evaluating an interface for the operation of OctArm, a biologically inspired robotic arm modeled after an octopus tentacle, are reported. Due to the many degrees-of-freedom (DOF) for the operator to control, such 'continuum' robotic limbs provide unique challenges for human operators because they do not map intuitively. Two modes have been developed to control the arm and reduce the DOF under the explicit direction of the operator. In coupled velocity (CV) mode, a joystick controls changes in arm curvature. In end-effector (EE) mode, a joystick controls the arm by moving the position of an endpoint along a straight line. In Experiment 1, participants used the two modes to grasp objects placed at different locations in a virtual reality modeling language (VRML). Objective measures of performance and subjective preferences were recorded. Results revealed lower grasp times and a subjective preference for the CV mode. Recommendations for improving the interface included providing additional feedback and implementation of an error recovery function. In Experiment 2, only the CV mode was tested with improved training of participants and several changes to the interface. The error recovery function was implemented, allowing participants to reverse through previously attained positions. The mean time to complete the trials in the second usability test was reduced by more than 4 minutes compared with the first usability test, confirming the interface changes improved performance. The results of these tests will be incorporated into future versions of the arm and improve future usability tests.

Armed-Conflict Risks Enhanced by Climate-Related Disasters in Ethnically Fractionalized Countries

NASA Astrophysics Data System (ADS)

Donner, R. V.; Schleussner, C. F.; Donges, J. F.; Schellnhuber, J.

2016-12-01

Social and political tensions keep on fueling armed conflicts around the world. Although each conflict is the result of an individual context-specific mixture of interconnected factors, ethnicity appears to play a prominent and almost ubiquitous role in many of them. This overall state of affairs is likely to be exacerbated by anthropogenic climate change and in particular climate-related natural disasters. Ethnic divides might serve as predetermined conflict lines in case of rapidly emerging societal tensions arising from disruptive events like natural disasters. Here, we hypothesize that climate-related disaster occurrence enhances armed-conflict outbreak risk in ethnically fractionalized countries. Using event coincidence analysis, we test this hypothesis based on data on armed-conflict outbreaks and climate-related natural disasters for the period 1980-2010. Globally, we find a coincidence rate of 9% regarding armed-conflict outbreak and disaster occurrence such as heat waves or droughts. Our analysis also reveals that, during the period in question, about 23% of conflict outbreaks in ethnically highly fractionalized countries robustly coincide with climatic calamities. Although we do not report evidence that climate-related disasters act as direct triggers of armed conflicts, the disruptive nature of these events seems to play out in ethnically fractionalized societies in a particularly tragic way. This observation has important implications for future security policies as several of the world's most conflict-prone regions, including North and Central Africa as well as Central Asia, are both exceptionally vulnerable to anthropogenic climate change and characterized by deep ethnic divides.

Map of Moessbauer Placement

NASA Technical Reports Server (NTRS)

2004-01-01

This elevation map of a soil target called 'Peak' was created from images taken by the microscopic imager located on the Mars Exploration Rover Spirit's instrument deployment device or 'arm.' The image reveals the various high and low points of this spot of soil after the Moessbauer spectrometer, another instrument on the rover's arm, was gently placed down on it. The blue areas are farthest away from the instrument; the red areas are closest. The variation in distance between blue and red areas is only 2 millimeters, or .08 of an inch. The images were acquired on sol 39 (February 11, 2004).

Dynamic model of the octopus arm. I. Biomechanics of the octopus reaching movement.

PubMed

Yekutieli, Yoram; Sagiv-Zohar, Roni; Aharonov, Ranit; Engel, Yaakov; Hochner, Binyamin; Flash, Tamar

2005-08-01

The octopus arm requires special motor control schemes because it consists almost entirely of muscles and lacks a rigid skeletal support. Here we present a 2D dynamic model of the octopus arm to explore possible strategies of movement control in this muscular hydrostat. The arm is modeled as a multisegment structure, each segment containing longitudinal and transverse muscles and maintaining a constant volume, a prominent feature of muscular hydrostats. The input to the model is the degree of activation of each of its muscles. The model includes the external forces of gravity, buoyancy, and water drag forces (experimentally estimated here). It also includes the internal forces generated by the arm muscles and the forces responsible for maintaining a constant volume. Using this dynamic model to investigate the octopus reaching movement and to explore the mechanisms of bend propagation that characterize this movement, we found the following. 1) A simple command producing a wave of muscle activation moving at a constant velocity is sufficient to replicate the natural reaching movements with similar kinematic features. 2) The biomechanical mechanism that produces the reaching movement is a stiffening wave of muscle contraction that pushes a bend forward along the arm. 3) The perpendicular drag coefficient for an octopus arm is nearly 50 times larger than the tangential drag coefficient. During a reaching movement, only a small portion of the arm is oriented perpendicular to the direction of movement, thus minimizing the drag force.

ShouldeRO, an alignment-free two-DOF rehabilitation robot for the shoulder complex.

PubMed

Dehez, Bruno; Sapin, Julien

2011-01-01

This paper presents a robot aimed to assist the shoulder movements of stroke patients during their rehabilitation process. This robot has the general form of an exoskeleton, but is characterized by an action principle on the patient no longer requiring a tedious and accurate alignment of the robot and patient's joints. It is constituted of a poly-articulated structure whose actuation is deported and transmission is ensured by Bowden cables. It manages two of the three rotational degrees of freedom (DOFs) of the shoulder. Quite light and compact, its proximal end can be rigidly fixed to the patient's back on a rucksack structure. As for its distal end, it is connected to the arm through passive joints and a splint guaranteeing the robot action principle, i.e. exert a force perpendicular to the patient's arm, whatever its configuration. This paper also presents a first prototype of this robot and some experimental results such as the arm angular excursions reached with the robot in the three joint planes. © 2011 IEEE

Cylindrical surface profile and diameter measuring tool and method

NASA Technical Reports Server (NTRS)

Currie, James R. (Inventor); Kissel, Ralph R. (Inventor); Smith, Earnest C. (Inventor); Oliver, Charles E. (Inventor); Redmon, John W., Sr. (Inventor); Wallace, Charles C. (Inventor); Swanson, Charles P. (Inventor)

1987-01-01

A tool is shown having a cross beam assembly made of beams joined by a center box structure. The assembly is adapted to be mounted by brackets to the outer end of a cylindrical case. The center box structure has a vertical shaft rotatably mounted therein and extending beneath the assembly. Secured to the vertical shaft is a radius arm which is adapted to rotate with the shaft. On the longer end of the radius arm is a measuring tip which contacts the cylindrical surface to be measured and which provides an electric signal representing the radius of the cylindrical surface from the center of rotation of the radius arm. An electric servomotor rotates the vertical shaft and an electronic resolver provides an electric signal representing the angle of rotation of the shaft. The electric signals are provided to a computer station which has software for its computer to calculate and print out the continuous circumference profile of the cylindrical surface, and give its true diameter and the deviations from the ideal circle.

Fatigue risks in the connections of sign support structures.

DOT National Transportation Integrated Search

2013-05-01

This research effort develops a reliability-based approach for prescribing inspection intervals for mast-arm sign support : structures corresponding to user-specified levels of fatigue-induced fracture risk. The resulting level of risk for a : partic...

[Terata catydidymus dicephalus: description of a case].

PubMed

Alò, P L; Trombetta, G; Marcone, P; De Quarto, A; Memeo, L; Di Tondo, U

1997-10-01

Conjoined twinning is the result of an abnormal developmental process of "twinning" in which two similar weighted and sized twins are partially conjoined and show a total symmetry independently from the pattern of conjunction. They are classified in three groups: Terata Catydidymus, Terata Anadidyma and Terata Anacatadidyma. Among Terata Catydidymus the dicephalus subtype is a rare abnormality with a severe prognosis compared to other subtypes as: diprosopus, pyophagus and ischiopagus. We report the case of a fetus at the 15th weeks of pregnancy. The external examination revealed severe diffuse somatic malformations consisting of dicephalia with a double neck in conjunction to a single chest, a single abdomen, a double spine conjoined distally near the sacrum, buds of ribs in between the two spines with mid clavicular and scapular fusion following the major axis of the two bones. Arms and legs revealed no abnormalities. Central nervous system structures were normally developed and the two hemispheres seemed completely separated and independent one to the other. We believe that the case described is interesting being Terata Catydidymus a rare phenomenon, being the dicephalus subtype still lesser frequent and its occurrence in males quite exceptional.

Identification of Nucleolus-Associated Chromatin Domains Reveals a Role for the Nucleolus in 3D Organization of the A. thaliana Genome.

PubMed

Pontvianne, Frédéric; Carpentier, Marie-Christine; Durut, Nathalie; Pavlištová, Veronika; Jaške, Karin; Schořová, Šárka; Parrinello, Hugues; Rohmer, Marine; Pikaard, Craig S; Fojtová, Miloslava; Fajkus, Jiří; Sáez-Vásquez, Julio

2016-08-09

The nucleolus is the site of rRNA gene transcription, rRNA processing, and ribosome biogenesis. However, the nucleolus also plays additional roles in the cell. We isolated nucleoli using fluorescence-activated cell sorting (FACS) and identified nucleolus-associated chromatin domains (NADs) by deep sequencing, comparing wild-type plants and null mutants for the nucleolar protein NUCLEOLIN 1 (NUC1). NADs are primarily genomic regions with heterochromatic signatures and include transposable elements (TEs), sub-telomeric regions, and mostly inactive protein-coding genes. However, NADs also include active rRNA genes and the entire short arm of chromosome 4 adjacent to them. In nuc1 null mutants, which alter rRNA gene expression and overall nucleolar structure, NADs are altered, telomere association with the nucleolus is decreased, and telomeres become shorter. Collectively, our studies reveal roles for NUC1 and the nucleolus in the spatial organization of chromosomes as well as telomere maintenance. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Curiosity Brushwork on Martian Bonanza King Target

NASA Image and Video Library

2014-08-18

NASA Curiosity Mars rover used the Dust Removal Tool on its robotic arm to brush aside reddish, more-oxidized dust, revealing a gray patch of less-oxidized rock material at a target called Bonanza King, visible from the rover Mastcam.

The 1994 Louisiana Maneuvers: Is Back to the Future What Our Army Needs?

DTIC Science & Technology

1992-05-26

can link current operational level training to future Combined Arms Training Strategies ( CATS ). The Army Chief of Staff s 1994 Louisiana Maneuver...tactical Combined Arms Training Strategy ( CATS ). An examination of Army tactical training strategies will reflect that operational forces can benefit...from both a CATS structure, and participation in an operational level Battle Command Training Program (BCTP) similar to division and corps BCTP’s

ASEAN and Indochina: A Strategy for Regional Stability in the 1980’s.

DTIC Science & Technology

1984-12-01

regional powers. The resultant regional balance of power is precarious, unstable, and ever threatens to deteriorate into armed conflict. The unequal...an armed force that is capable of large scale defense. Ironically, while ostensibly defensively motivated, these efforts have resulted in a war machine... resulted in the atmosphere of tense uncertainty in Southeast Asia today. In contrast to Vietnamese motivations for their force -- structure, the other

An arms race between producers and scroungers can drive the evolution of social cognition

PubMed Central

2014-01-01

The “social intelligence hypothesis” states that the need to cope with complexities of social life has driven the evolution of advanced cognitive abilities. It is usually invoked in the context of challenges arising from complex intragroup structures, hierarchies, and alliances. However, a fundamental aspect of group living remains largely unexplored as a driving force in cognitive evolution: the competition between individuals searching for resources (producers) and conspecifics that parasitize their findings (scroungers). In populations of social foragers, abilities that enable scroungers to steal by outsmarting producers, and those allowing producers to prevent theft by outsmarting scroungers, are likely to be beneficial and may fuel a cognitive arms race. Using analytical theory and agent-based simulations, we present a general model for such a race that is driven by the producer–scrounger game and show that the race’s plausibility is dramatically affected by the nature of the evolving abilities. If scrounging and scrounging avoidance rely on separate, strategy-specific cognitive abilities, arms races are short-lived and have a limited effect on cognition. However, general cognitive abilities that facilitate both scrounging and scrounging avoidance undergo stable, long-lasting arms races. Thus, ubiquitous foraging interactions may lead to the evolution of general cognitive abilities in social animals, without the requirement of complex intragroup structures. PMID:24822021

A Randomized Controlled Trial of Two Syntactic Treatment Procedures With Cantonese-Speaking, School-Age Children With Language Disorders.

PubMed

To, Carol K S; Lui, Hoi Ming; Li, Xin Xin; Lam, Gary Y H

2015-08-01

In this study, we aimed to evaluate the efficacy of sentence-combining (SC) and narrative-based (NAR) intervention approaches to syntax intervention using a randomized-controlled-trial design. Fifty-two Cantonese-speaking, school-age children with language impairment were assigned randomly to either the SC or the NAR treatment arm. Seven children did not receive treatment as assigned. Intervention in both arms targeted the same complex syntactical structures. The SC group focused on sentence combination training, whereas the NAR group made use of narratives in which the target structures were embedded. Pretest and posttest performances measured using a standardized language assessment were subjected to analyses of covariance mixed-effect-model analyses of variance. Children in both treatment arms demonstrated significant growth after 4 months of intervention. The main effect between treatment arms and time was not significant after controlling the pretest performance, suggesting that both treatment approaches showed similar effects. The main effect of time was significant. This study provided evidence to support language intervention in the school years in Cantonese-speaking children. However, neither approach was shown to be more efficacious than the other. Future researchers could examine the effects of a longer treatment period and include functional outcome measures.

Polyplex formation between four-arm poly(ethylene oxide)-b-poly(2-(diethylamino)ethyl methacrylate) and plasmid DNA in gene delivery.

PubMed

He, E; Yue, C Y; Simeon, F; Zhou, L H; Too, H P; Tam, K C

2009-12-01

Amphiphilic polyelectrolytes comprising cationic and uncharged hydrophilic segments condensed negatively charged DNA to form a core-shell structure stabilized by a layer of hydrophilic corona chains. At physiological pH, four-arm star-shaped poly(ethylene oxide)-b-poly(2-(diethylamino)ethyl methacrylate) (four-arm PEO-b-PDEAEMA) block copolymer possessed positively charged amine groups that interacted with negatively charged plasmid DNA to form polymer/DNA complexes. The mechanism and physicochemical properties of the complex formation were investigated at varying molar ratio of amine groups on polymer chains and phosphate group on plasmid DNA segments (N/P ratio). The capability of the star block copolymer to condense DNA was demonstrated through gel electrophoresis and ethidium bromide exclusion assay. In the absence of salt, the hydrodynamic radius of polyplexes was about 94 nm at low polymer/DNA ratio, and it decreased to about 34 nm at large N/P ratios, forming a compact spherical structure with a weighted average molecular weight of 4.39 +/- 0.22 x 10(6) g/mol. Approximately 15 polymeric chains were required to condense a plasmid DNA. The addition of monovalent salt to the polyplexes significantly altered the size of the complexes, which would have an impact on cell transfection. Because of the electrostatic interaction induced by the diffusion of small ions, the polyplex increased in size to about 53 nm with a less compact structure. In vitro cytotoxicty of polymer and polymer/pDNA complexes were evaluated, and the polyplexes exhibited low toxicity at low N/P ratios. At N/P ratio of 4.5, the four-arm PEO-b-PDEAEMA showed the highest level of transfection in Neuro-2A cells. These observations showed that the star-shaped multi-arm polymers offers interesting properties in self-association and condensation ability for plasmid DNA and can serve as a nonviral DNA delivery system. Copyright 2008 Wiley Periodicals, Inc.

Solution NMR analyses of the anticodon arms of proteinogenic and non-proteinogenic tRNAGly

PubMed Central

Chang, Andrew T.; Nikonowicz, Edward P.

2012-01-01

Although the fate of most tRNA molecules in the cell is aminoacylation and delivery to the ribosome, some tRNAs are destined to fulfill other functional roles. In addition to their central role in translation, tRNA molecules participate in processes such as regulation of gene expression, bacterial cell wall biosynthesis, viral replication, antibiotic biosynthesis, and suppression of alternative splicing. In bacteria, glycyl-tRNA molecules with anticodon sequences GCC and UCC exhibit multiple extra-translational functions including transcriptional regulation and cell wall biosynthesis. We have determined the high-resolution structures of three glycyl-tRNA anticodon arms with anticodon sequences GCC and UCC. Two of the tRNA molecules are proteinogenic (tRNAGly,GCC and tRNAGly,UCC) and the third is non-proteinogenic (np-tRNAGly,UCC) and participates in cell wall biosynthesis. The UV-monitored thermal melting curves show that the anticodon arm of tRNAGly,UCC with a loop-closing C-A+ base pair melts at a 10 °C lower temperature than those of tRNAGly,GCC or np-tRNAGly,UCC. U-A and C-G pairs close the loops of the later two molecules and enhance stem stability. Mg2+ stabilizes the tRNAGly,UCC anticodon arm and lessens the Tm differential. The structures of the three tRNAGly anticodon arms exhibit small differences between one another, but none of them form the classical U-turn motif. The anticodon loop of tRNAGly,GCC becomes more dynamic and disordered in the presence of multivalent cations, whereas metal ion coordination in the anticodon loops of tRNAGly,UCC and np-tRNAGly,UCC establishes conformational homogeneity. The conformational similarity of the molecules is greater than their functional differences might suggest. Because aminoacylation of the full-length tRNA molecules is accomplished by one tRNA synthetase, the similar structural context of the loop may facilitate efficient recognition of each of the anticodon sequences. PMID:22468768

Coupling of Lever Arm Swing and Biased Brownian Motion in Actomyosin

PubMed Central

Nie, Qing-Miao; Togashi, Akio; Sasaki, Takeshi N.; Takano, Mitsunori; Sasai, Masaki; Terada, Tomoki P.

2014-01-01

An important unresolved problem associated with actomyosin motors is the role of Brownian motion in the process of force generation. On the basis of structural observations of myosins and actins, the widely held lever-arm hypothesis has been proposed, in which proteins are assumed to show sequential structural changes among observed and hypothesized structures to exert mechanical force. An alternative hypothesis, the Brownian motion hypothesis, has been supported by single-molecule experiments and emphasizes more on the roles of fluctuating protein movement. In this study, we address the long-standing controversy between the lever-arm hypothesis and the Brownian motion hypothesis through in silico observations of an actomyosin system. We study a system composed of myosin II and actin filament by calculating free-energy landscapes of actin-myosin interactions using the molecular dynamics method and by simulating transitions among dynamically changing free-energy landscapes using the Monte Carlo method. The results obtained by this combined multi-scale calculation show that myosin with inorganic phosphate (Pi) and ADP weakly binds to actin and that after releasing Pi and ADP, myosin moves along the actin filament toward the strong-binding site by exhibiting the biased Brownian motion, a behavior consistent with the observed single-molecular behavior of myosin. Conformational flexibility of loops at the actin-interface of myosin and the N-terminus of actin subunit is necessary for the distinct bias in the Brownian motion. Both the 5.5–11 nm displacement due to the biased Brownian motion and the 3–5 nm displacement due to lever-arm swing contribute to the net displacement of myosin. The calculated results further suggest that the recovery stroke of the lever arm plays an important role in enhancing the displacement of myosin through multiple cycles of ATP hydrolysis, suggesting a unified movement mechanism for various members of the myosin family. PMID:24762409

Coupling of lever arm swing and biased Brownian motion in actomyosin.

PubMed

Nie, Qing-Miao; Togashi, Akio; Sasaki, Takeshi N; Takano, Mitsunori; Sasai, Masaki; Terada, Tomoki P

2014-04-01

An important unresolved problem associated with actomyosin motors is the role of Brownian motion in the process of force generation. On the basis of structural observations of myosins and actins, the widely held lever-arm hypothesis has been proposed, in which proteins are assumed to show sequential structural changes among observed and hypothesized structures to exert mechanical force. An alternative hypothesis, the Brownian motion hypothesis, has been supported by single-molecule experiments and emphasizes more on the roles of fluctuating protein movement. In this study, we address the long-standing controversy between the lever-arm hypothesis and the Brownian motion hypothesis through in silico observations of an actomyosin system. We study a system composed of myosin II and actin filament by calculating free-energy landscapes of actin-myosin interactions using the molecular dynamics method and by simulating transitions among dynamically changing free-energy landscapes using the Monte Carlo method. The results obtained by this combined multi-scale calculation show that myosin with inorganic phosphate (Pi) and ADP weakly binds to actin and that after releasing Pi and ADP, myosin moves along the actin filament toward the strong-binding site by exhibiting the biased Brownian motion, a behavior consistent with the observed single-molecular behavior of myosin. Conformational flexibility of loops at the actin-interface of myosin and the N-terminus of actin subunit is necessary for the distinct bias in the Brownian motion. Both the 5.5-11 nm displacement due to the biased Brownian motion and the 3-5 nm displacement due to lever-arm swing contribute to the net displacement of myosin. The calculated results further suggest that the recovery stroke of the lever arm plays an important role in enhancing the displacement of myosin through multiple cycles of ATP hydrolysis, suggesting a unified movement mechanism for various members of the myosin family.

Investigating early-type galaxy evolution with a multiwavelength approach. II. The UV structure of 11 galaxies with Swift-UVOT

NASA Astrophysics Data System (ADS)

Rampazzo, R.; Mazzei, P.; Marino, A.; Uslenghi, M.; Trinchieri, G.; Wolter, A.

2017-06-01

Context. GALEX detected a significant fraction of early-type galaxies, in particular S0s, showing far-UV bright structures, sometimes involving an entire galaxy out to its outskirts. These features suggest the presence of either recent ongoing and/or prolonged star formation episodes, shedding new light on the evolution of these systems. Aims: We aim at understanding the evolutionary path[s] of these early-type galaxies and the mechanisms at the origin of their UV-bright structures. We investigate with a multiwavelength approach the link between the inner and outer galaxy regions of a set of 11 early-type galaxies that were selected because of their nearly passive stage of evolution in the nuclear region. Methods: This paper, second of a series, focuses on the information coming from the comparison between UV features detected by Swift-UVOT, which trace recent star formation, and the galaxy optical structure, which maps older stellar populations. We performed a surface photometric study of these early-type galaxies, observed with the Swift-UVOT UV filters W2 2030 Å λ0, M2 2231 Å λ0, W1 2634 Å λ0 and the UBV bands. BVRI photometry from other sources in the literature was also used. Our integrated magnitude measurements were analyzed and compared with corresponding values in the literature. We characterize the overall galaxy structure that best fits the UV and optical luminosity profiles using a single Sérsic law. Results: The galaxies NGC 1366, NGC 1426, NGC 3818, NGC 3962, and NGC 7192 show featureless luminosity profiles. Excluding NGC 1366, which has a clear edge-on disk (n ≈ 1-2), and NGC 3818, the remaining three galaxies have Sérsic's indices n ≈ 3-4 in the optical and a lower index in the UV. Bright ring- or arm-like structures are revealed by UV images and luminosity profiles of NGC 1415, NGC 1533, NGC 1543, NGC 2685, NGC 2974, and IC 2006. The ring- or arm-like structures differ from galaxy to galaxy. Sérsic indices of UV profiles for these galaxies are in the range n = 1.5-3 both in S0s and in galaxies classified as bona fide ellipticals, such as NGC 2974 and IC 2006. We note that in our sample optical Sérsic indices are usually higher than in the UV indices. (M2-V) color profiles are bluer in ring- or arm-like structures than in the galaxy body. Conclusions: The lower values of Sérsic indices in the UV bands with respect to optical bands, suggesting the presence of a disk, point out that the role of the dissipation cannot be neglected in recent evolutionary phases of these early-type galaxies. Full Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/602/A97

Separate effects of sex hormones and sex chromosomes on brain structure and function revealed by high-resolution magnetic resonance imaging and spatial navigation assessment of the Four Core Genotype mouse model.

PubMed

Corre, Christina; Friedel, Miriam; Vousden, Dulcie A; Metcalf, Ariane; Spring, Shoshana; Qiu, Lily R; Lerch, Jason P; Palmert, Mark R

2016-03-01

Males and females exhibit several differences in brain structure and function. To examine the basis for these sex differences, we investigated the influences of sex hormones and sex chromosomes on brain structure and function in mice. We used the Four Core Genotype (4CG) mice, which can generate both male and female mice with XX or XY sex chromosome complement, allowing the decoupling of sex chromosomes from hormonal milieu. To examine whole brain structure, high-resolution ex vivo MRI was performed, and to assess differences in cognitive function, mice were trained on a radial arm maze. Voxel-wise and volumetric analyses of MRI data uncovered a striking independence of hormonal versus chromosomal influences in 30 sexually dimorphic brain regions. For example, the bed nucleus of the stria terminalis and the parieto-temporal lobe of the cerebral cortex displayed steroid-dependence while the cerebellar cortex, corpus callosum, and olfactory bulbs were influenced by sex chromosomes. Spatial learning and memory demonstrated strict hormone-dependency with no apparent influence of sex chromosomes. Understanding the influences of chromosomes and hormones on brain structure and function is important for understanding sex differences in brain structure and function, an endeavor that has eventual implications for understanding sex biases observed in the prevalence of psychiatric disorders.

Tensile testing of thin-film microstructures

NASA Astrophysics Data System (ADS)

Greek, Staffan; Johansson, Stefan A. I.

1997-09-01

The mechanical properties of thin film microstructures depend on size and shape and on the film manufacturing process. Hence, the test structures that are used to measure mechanical properties should have dimensions of the same order of magnitude as an application structure. The microstructures are easily monitored in a scanning electron microscope (SEM), but to be handled and tested in situ a micromanipulator was developed. The parts of the micromanipulator essential to the tests are two independently moveable tables driven by electric motors. The test structures and a testing unit are mounted on the tables. A testing unit was designed to measure force and displacement with high resolution. The testing unit consists of an arm actuated by a piezoelectric element and equipped with a probe. An optical encoder measures the movement of the arm, while strain gauges measure the force in the arm. Test structures consist typically of a released beam fixed at one end with a ring at the other. The micromanipulator is used to position the probe of the testing unit in the ring. The testing unit then executed a tensile test of the beam. Test structures of polysilicon films produced under various process conditions were used to verify the possibility of measuring Young's modulus with an accuracy of +/- 5 percent, as well as fracture strength.Young's modulus is calculated using the difference in elongation for different beam lengths. The fracture strength of the beams was evaluated with Weibull statistics.

Compensation of non-ideal beam splitter polarization distortion effect in Michelson interferometer

NASA Astrophysics Data System (ADS)

Liu, Yeng-Cheng; Lo, Yu-Lung; Liao, Chia-Chi

2016-02-01

A composite optical structure consisting of two quarter-wave plates and a single half-wave plate is proposed for compensating for the polarization distortion induced by a non-ideal beam splitter in a Michelson interferometer. In the proposed approach, the optimal orientations of the optical components within the polarization compensator are determined using a genetic algorithm (GA) such that the beam splitter can be treated as a free-space medium and modeled using a unit Mueller matrix accordingly. Two implementations of the proposed polarization controller are presented. In the first case, the compensator is placed in the output arm of Michelson interferometer such that the state of polarization of the interfered output light is equal to that of the input light. However, in this configuration, the polarization effects induced by the beam splitter in the two arms of the interferometer structure cannot be separately addressed. Consequently, in the second case, compensator structures are placed in the Michelson interferometer for compensation on both the scanning and reference beams. The practical feasibility of the proposed approach is introduced by considering a Mueller polarization-sensitive (PS) optical coherence tomography (OCT) structure with three polarization controllers in the input, reference and sample arms, respectively. In general, the results presented in this study show that the proposed polarization controller provides an effective and experimentally-straightforward means of compensating for the polarization distortion effects induced by the non-ideal beam splitters in Michelson interferometers and Mueller PS-OCT structures.

Composite body movements modulate numerical cognition: evidence from the motion-numerical compatibility effect

PubMed Central

Cheng, Xiaorong; Ge, Hui; Andoni, Deljfina; Ding, Xianfeng; Fan, Zhao

2015-01-01

A recent hierarchical model of numerical processing, initiated by Fischer and Brugger (2011) and Fischer (2012), suggested that situated factors, such as different body postures and body movements, can influence the magnitude representation and bias numerical processing. Indeed, Loetscher et al. (2008) found that participants’ behavior in a random number generation task was biased by head rotations. More small numbers were reported after leftward than rightward head turns, i.e., a motion-numerical compatibility effect. Here, by carrying out two experiments, we explored whether similar motion-numerical compatibility effects exist for movements of other important body components, e.g., arms, and for composite body movements as well, which are basis for complex human activities in many ecologically meaningful situations. In Experiment 1, a motion-numerical compatibility effect was observed for lateral rotations of two body components, i.e., the head and arms. Relatively large numbers were reported after making rightward compared to leftward movements for both lateral head and arm turns. The motion-numerical compatibility effect was observed again in Experiment 2 when participants were asked to perform composite body movements of congruent movement directions, e.g., simultaneous head left turns and arm left turns. However, it disappeared when the movement directions were incongruent, e.g., simultaneous head left turns and arm right turns. Taken together, our results extended Loetscher et al.’s (2008) finding by demonstrating that their effect is effector-general and exists for arm movements. Moreover, our study reveals for the first time that the impact of spatial information on numerical processing induced by each of the two sensorimotor-based situated factors, e.g., a lateral head turn and a lateral arm turn, can cancel each other out. PMID:26594188

A Short and Distinct Time Window for Recovery of Arm Motor Control Early After Stroke Revealed With a Global Measure of Trajectory Kinematics.

PubMed

Cortes, Juan C; Goldsmith, Jeff; Harran, Michelle D; Xu, Jing; Kim, Nathan; Schambra, Heidi M; Luft, Andreas R; Celnik, Pablo; Krakauer, John W; Kitago, Tomoko

2017-06-01

Studies demonstrate that most arm motor recovery occurs within three months after stroke, when measured with standard clinical scales. Improvements on these measures, however, reflect a combination of recovery in motor control, increases in strength, and acquisition of compensatory strategies. To isolate and characterize the time course of recovery of arm motor control over the first year poststroke. Longitudinal study of 18 participants with acute ischemic stroke. Motor control was evaluated using a global kinematic measure derived from a 2-dimensional reaching task designed to minimize the need for antigravity strength and prevent compensation. Arm impairment was evaluated with the Fugl-Meyer Assessment of the upper extremity (FMA-UE), activity limitation with the Action Research Arm Test (ARAT), and strength with biceps dynamometry. Assessments were conducted at: 1.5, 5, 14, 27, and 54 weeks poststroke. Motor control in the paretic arm improved up to week 5, with no further improvement beyond this time point. In contrast, improvements in the FMA-UE, ARAT, and biceps dynamometry continued beyond 5 weeks, with a similar magnitude of improvement between weeks 5 and 54 as the one observed between weeks 1.5 and 5. Recovery after stroke plateaued much earlier for arm motor control, isolated with a global kinematic measure, compared to motor function assessed with clinical scales. This dissociation between the time courses of kinematic and clinical measures of recovery may be due to the contribution of strength improvement to the latter. Novel interventions, focused on the first month poststroke, will be required to exploit the narrower window of spontaneous recovery for motor control.

Reduced activation in the ventral striatum during probabilistic decision-making in patients in an at-risk mental state

PubMed Central

Rausch, Franziska; Mier, Daniela; Eifler, Sarah; Fenske, Sabrina; Schirmbeck, Frederike; Englisch, Susanne; Schilling, Claudia; Meyer-Lindenberg, Andreas; Kirsch, Peter; Zink, Mathias

2015-01-01

Background Patients with schizophrenia display metacognitive impairments, such as hasty decision-making during probabilistic reasoning — the “jumping to conclusion” bias (JTC). Our recent fMRI study revealed reduced activations in the right ventral striatum (VS) and the ventral tegmental area (VTA) to be associated with decision-making in patients with schizophrenia. It is unclear whether these functional alterations occur in the at-risk mental state (ARMS). Methods We administered the classical beads task and fMRI among ARMS patients and healthy controls matched for age, sex, education and premorbid verbal intelligence. None of the ARMS patients was treated with antipsychotics. Both tasks request probabilistic decisions after a variable amount of stimuli. We evaluated activation during decision-making under certainty versus uncertainty and the process of final decision-making. Results We included 24 AMRS patients and 24 controls in our study. Compared with controls, ARMS patients tended to draw fewer beads and showed significantly more JTC bias in the classical beads task, mirroring findings in patients with schizophrenia. During fMRI, ARMS patients did not demonstrate JTC bias on the behavioural level, but showed a significant hypoactivation in the right VS during the decision stage. Limitations Owing to the cross-sectional design of the study, results are constrained to a better insight into the neurobiology of risk constellations, but not pre-psychotic stages. Nine of the ARMS patients were treated with antidepressants and/or lorazepam. Conclusion As in patients with schizophrenia, a striatal hypoactivation was found in ARMS patients. Confounding effects of antipsychotic medication can be excluded. Our findings indicate that error prediction signalling and reward anticipation may be linked to striatal dysfunction during prodromal stages and should be examined for their utility in predicting transition risk. PMID:25622039

Dissecting the Role of CHITINASE-LIKE1 in Nitrate-Dependent Changes in Root Architecture1[C][W

PubMed Central

Hermans, Christian; Porco, Silvana; Vandenbussche, Filip; Gille, Sascha; De Pessemier, Jérôme; Van Der Straeten, Dominique; Verbruggen, Nathalie; Bush, Daniel R.

2011-01-01

The root phenotype of an Arabidopsis (Arabidopsis thaliana) mutant of CHITINASE-LIKE1 (CTL1), called arm (for anion-related root morphology), was previously shown to be conditional on growth on high nitrate, chloride, or sucrose. Mutants grown under restrictive conditions displayed inhibition of primary root growth, radial swelling, proliferation of lateral roots, and increased root hair density. We found here that the spatial pattern of CTL1 expression was mainly in the root and root tips during seedling development and that the protein localized to the cell wall. Fourier-transform infrared microspectroscopy of mutant root tissues indicated differences in spectra assigned to linkages in cellulose and pectin. Indeed, root cell wall polymer composition analysis revealed that the arm mutant contained less crystalline cellulose and reduced methylesterification of pectins. We also explored the implication of growth regulators on the phenotype of the mutant response to the nitrate supply. Exogenous abscisic acid application inhibited more drastically primary root growth in the arm mutant but failed to repress lateral branching compared with the wild type. Cytokinin levels were higher in the arm root, but there were no changes in mitotic activity, suggesting that cytokinin is not directly involved in the mutant phenotype. Ethylene production was higher in arm but inversely proportional to the nitrate concentration in the medium. Interestingly, eto2 and eto3 ethylene overproduction mutants mimicked some of the conditional root characteristics of the arm mutant on high nitrate. Our data suggest that ethylene may be involved in the arm mutant phenotype, albeit indirectly, rather than functioning as a primary signal. PMID:21949212

Attractiveness of Host Plant Volatile Extracts to the Asian Citrus Psyllid, Diaphorina citri, is Reduced by Terpenoids from the Non-Host Cashew.

PubMed

Fancelli, Marilene; Borges, Miguel; Laumann, Raul A; Pickett, John A; Birkett, Michael A; Blassioli-Moraes, Maria C

2018-04-01

Diaphorina citri is a vector of the bacterial causative agent of Huanglongbing (HLB = Citrus greening), a severe disease affecting citrus crops. As there is no known control for HLB, manipulating insect behaviour through deployment of semiochemicals offers a promising opportunity for protecting citrus crops. The behavioural responses of D. citri to plant volatiles, and the identity of these plant volatiles were investigated. Volatiles were collected from host plants Murraya paniculata, Citrus sinensis, C. reshni, C. limettioides, Poncirus trifoliata, and from non-host plants Psidium guajava, Mangifera indica, Anacardium occidentale. In behavioural assays, female D. citri spent more time in the arms containing volatiles from either M. paniculata or C. sinensis compared to the control arms. When D. citri was exposed to volatiles collected from A. occidentale, they preferred the control arm. Volatiles emitted from the other studied plants did not influence the foraging behaviour of D. citri. Chemical analyses of volatile extracts from C. sinensis, M. paniculata, and A. occidentale revealed the presence of the terpenoids (E)-4,8-dimethylnona-1,3,7-triene (DMNT) and (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT) in higher amounts in A. occidentale. In further behavioural bioassays, female D. citri spent less time in arms containing a synthetic blend of DMNT and TMTT compared to the control arms. Female D. citri also spent less time in arms containing the synthetic blend in combination with volatile extracts from either M. paniculata or C. sinensis compared to the control arms. Results suggest that higher release of the two terpenoids by A. occidentale make this species unattractive to D. citri, and that the terpenoids could be used in reducing colonisation of citrus plants and therefore HLB infection.

Comparison between free-hand and O-arm-based navigated posterior lumbar interbody fusion in elderly cohorts with three-level lumbar degenerative disease.

PubMed

Wang, Yucheng; Chen, Kangwu; Chen, Hao; Zhang, Kai; Lu, Jian; Mao, Haiqing; Yang, Huilin

2018-06-06

This retrospective cohort study aims to evaluate the effects of introducing the O-arm-based navigation technique into the traditional posterior lumbar interbody fusion (PLIF) procedure treating elderly patients with three-level lumbar degenerative diseases. Forty-one consecutive elderly patients were enrolled according to the criteria. There were 21 patients in the free-hand group and 20 patients in the O-arm group. Both two groups underwent the PLIF with or without the O-arm-based navigation technique. The demographic features, clinical data and outcomes, and radiological information were collected for further analysis. The average follow-up time was 18.3 (range, 12-28) months in the free-hand group and 16.7 (range, 12-24) months in the O-arm group. Comparison between two groups revealed no significant difference regarding demographic features. The operation time took in the navigation group was significantly less than that in the free-hand group (222.55 ± 38.00 mins versus 255.19 ± 40.26 mins, P < 0.05). Both VAS and ODI were improved post-operatively in two groups while comparison between groups showed no difference. The accuracy rate of pedicle screw positioning was 88.7% in the free-hand group to 96.9% in the O-arm group (P < 0.05). The O-arm-based navigation is an efficacious auxiliary technique which could significantly improve the accuracy of pedicle screw insertion, especially in cases of patients with complex anatomic degenerative diseases, without sacrificing the feasibility and reliable outcome of traditional PLIF.

Reduced activation in the ventral striatum during probabilistic decision-making in patients in an at-risk mental state.

PubMed

Rausch, Franziska; Mier, Daniela; Eifler, Sarah; Fenske, Sabrina; Schirmbeck, Frederike; Englisch, Susanne; Schilling, Claudia; Meyer-Lindenberg, Andreas; Kirsch, Peter; Zink, Mathias

2015-05-01

Patients with schizophrenia display metacognitive impairments, such as hasty decision-making during probabilistic reasoning - the "jumping to conclusion" bias (JTC). Our recent fMRI study revealed reduced activations in the right ventral striatum (VS) and the ventral tegmental area (VTA) to be associated with decision-making in patients with schizophrenia. It is unclear whether these functional alterations occur in the at-risk mental state (ARMS). We administered the classical beads task and fMRI among ARMS patients and healthy controls matched for age, sex, education and premorbid verbal intelligence. None of the ARMS patients was treated with antipsychotics. Both tasks request probabilistic decisions after a variable amount of stimuli. We evaluated activation during decision-making under certainty versus uncertainty and the process of final decision-making. We included 24 AMRS patients and 24 controls in our study. Compared with controls, ARMS patients tended to draw fewer beads and showed significantly more JTC bias in the classical beads task, mirroring findings in patients with schizophrenia. During fMRI, ARMS patients did not demonstrate JTC bias on the behavioural level, but showed a significant hypoactivation in the right VS during the decision stage. Owing to the cross-sectional design of the study, results are constrained to a better insight into the neurobiology of risk constellations, but not prepsychotic stages. Nine of the ARMS patients were treated with antidepressants and/or lorazepam. As in patients with schizophrenia, a striatal hypoactivation was found in ARMS patients. Confounding effects of antipsychotic medication can be excluded. Our findings indicate that error prediction signalling and reward anticipation may be linked to striatal dysfunction during prodromal stages and should be examined for their utility in predicting transition risk.

ARM Cloud Radar Simulator Package for Global Climate Models Value-Added Product

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yuying; Xie, Shaocheng

It has been challenging to directly compare U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility ground-based cloud radar measurements with climate model output because of limitations or features of the observing processes and the spatial gap between model and the single-point measurements. To facilitate the use of ARM radar data in numerical models, an ARM cloud radar simulator was developed to converts model data into pseudo-ARM cloud radar observations that mimic the instrument view of a narrow atmospheric column (as compared to a large global climate model [GCM] grid-cell), thus allowing meaningful comparison between model outputmore » and ARM cloud observations. The ARM cloud radar simulator value-added product (VAP) was developed based on the CloudSat simulator contained in the community satellite simulator package, the Cloud Feedback Model Intercomparison Project (CFMIP) Observation Simulator Package (COSP) (Bodas-Salcedo et al., 2011), which has been widely used in climate model evaluation with satellite data (Klein et al., 2013, Zhang et al., 2010). The essential part of the CloudSat simulator is the QuickBeam radar simulator that is used to produce CloudSat-like radar reflectivity, but is capable of simulating reflectivity for other radars (Marchand et al., 2009; Haynes et al., 2007). Adapting QuickBeam to the ARM cloud radar simulator within COSP required two primary changes: one was to set the frequency to 35 GHz for the ARM Ka-band cloud radar, as opposed to 94 GHz used for the CloudSat W-band radar, and the second was to invert the view from the ground to space so as to attenuate the beam correctly. In addition, the ARM cloud radar simulator uses a finer vertical resolution (100 m compared to 500 m for CloudSat) to resolve the more detailed structure of clouds captured by the ARM radars. The ARM simulator has been developed following the COSP workflow (Figure 1) and using the capabilities available in COSP wherever possible. The ARM simulator is written in Fortran 90, just as is the COSP. It is incorporated into COSP to facilitate use by the climate modeling community. In order to evaluate simulator output, the observational counterpart of the simulator output, radar reflectivity-height histograms (CFAD) is also generated from the ARM observations. This report includes an overview of the ARM cloud radar simulator VAP and the required simulator-oriented ARM radar data product (radarCFAD) for validating simulator output, as well as a user guide for operating the ARM radar simulator VAP.« less